Overview

General comment

Production covered

Package-on-package stack: a wire-bonded memory package is reflowed onto a flip-chip processor package, joined through vias formed in the lower mold cap. Functional unit is one package STARTED: the reference flow is a single package entering assembly, and the activities listed run through completed assembly and final test of that package.

Modelling choices

By the count-once yield-ownership convention, the gross-up from packages started to good packages is carried by the consuming IC or component dataset, not here.

Technology: PoP
Geography: Global average data from equipment vendor specifications and industry literature

System boundary

The figure groups this dataset's unit processes by class. It is not a count of manufacturing steps — each process runs over as many passes as the flow requires, and those pass counts ship with the dataset.

Download this figure (SVG)

Data quality and references

Composite DQI 1.9 Very good

Reliability

2.8

Completeness

2.1

Temporal

1.3

Geographic

2.0

Technological

1.4

Pedigree scores follow the ecoinvent data-quality matrix: 1 is the best attainable, 5 the weakest. The composite is their aggregate.

Sampling procedure: Equipment vendor specifications, academic papers, industry literature
Coverage status: Partial
Pedigree-scored source files: 23 — the source records behind this dataset's manufacturing operations. Each carries the five pedigree axes above; the composite DQI aggregates them.

Technosphere inputs

34 flows. Quantities are not published; they ship with the dataset on Circa.

CF₄ production Process gasg · -49.2% / +69.5%

Derivation basis: No retrievable public document identified

No source is attached to this row.
Source citations: Not stated
Upstream REEL dataset: Carbon tetrafluoride (CF4)
Background dataset: Modelled by REEL; see the upstream dataset above.
Uncertainty: -49.2% / +69.5% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

SF₆ production Process gasg · -49% / +53.1%

Derivation basis: No retrievable public document identified

No source is attached to this row.
Source citations: Not stated
Upstream REEL dataset: Sulfur hexafluoride (SF6)
Background dataset: Modelled by REEL; see the upstream dataset above.
Uncertainty: -49% / +53.1% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

ArF Photoresist Process chemicalg · -33.4% / +66.6%

Source citations: microsi.com (date not recorded). Flack, W.W., Nguyen, H.-A. (Ultratech), Capsuto, E. (Shin-Etsu MicroSi), Abreau, K. (STEAG Hamatech USA), "Characterization of 100 Micron Thick Positive Photoresist on 300 mm Wafers", SPIE 2005 #5753-103. PDF document.
nrf.aux.eng.ufl.edu (date not recorded). AZ 9260 PHOTORESIST (520CPS) (US) Material Safety Data Sheet, substance key SXR109902, revision date 03/03/2010. PDF document.
Upstream REEL dataset: ArF Photoresist (193nm)
Background dataset: Modelled by REEL; see the upstream dataset above.
Uncertainty: -33.4% / +66.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

TMAH Developer (2.38% solution) Process chemicalg · ±33.3%

Derivation basis: Developer usage

No source is attached to this row.
Source citations: Not stated
Upstream REEL dataset: TMAH Developer (2.38% solution) (N(CH3)4OH (aq))
Background dataset: Modelled by REEL; see the upstream dataset above.
Uncertainty: ±33.3% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Water supply (municipal) Waterm3 · -54.8% / +72.4%

Derivation basis: Calculated from process-water and ultrapure-water demand across all manufacturing operations, plus facility water allocated to each finished unit. The fresh intake shown is that demand less the share reused under the water-recycling scenario this dataset assumes, and wastewater follows the same balance.

No source is attached to this row.
Source citations: Not stated
Upstream REEL dataset: Water Supply (Municipal)
Background dataset: Modelled by REEL; see the upstream dataset above.
Notes: Net fresh-water intake, supplied as municipal water
Uncertainty: -54.8% / +72.4% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: m3

Electricity, Taiwan (TW) ElectricitykWh · -66.3% / +145.7%

Derivation basis: Calculated from equipment energy across all manufacturing operations. It also includes the assembly site's facility overhead: air handling and cleanroom conditioning, chilled water, compressed dry air, exhaust and dust collection, wastewater treatment and uninterruptible power.
REEL derivation: engineering estimate of per-package laser-marking energy from the marker system power rating and line throughput; no single published document reports this per-package value

The sources below come from the manufacturing operations behind this row.
Sources (inherited): Inherited, rolled up from the contributing process steps:

advantest.com (2024). Advantest Unveils New Ultra-High-Current Power Supply for V93000 EXA Scale SoC Test System. Web page.

teradyne.com. Titan HP | Teradyne.

directindustry.es (date not recorded). Sistema de prueba para la industria electrónica - Titan HP - Teradyne - para semiconductores / modular / de alta potencia. Web page.

electronics360.globalspec.com (date not recorded). Chip complexity drives surge in system-level testing | Electronics360. Web page.

teradyne.com (date not recorded). Titan System Level Test. Web page.

sst.semiconductor-digest.com (date not recorded). Semiconductor Digest - Package-on-package (PoP) with Through-mold Vias (2008). Trade press article.

directindustry.com (date not recorded). DirectIndustry - Kulicke & Soffa IConn (ProCu) PLUS wire bonder listing (1.5 kVA nominal / 2.6 kVA max).

c2mi.ca (date not recorded). C2MI - IConn ProCu Plus LA equipment listing.

electronicspecifier.com (date not recorded). electronicspecifier - ASMPT unveils latest wire bonder (Eagle AERO, up to 24 2-mm connections/s), 26 Sep 2022. Trade press article.

Hu et al. (2019). Analysis of energy efficiency improvement of high-tech fabrication plants. International Journal of Low-Carbon Technologies. DOI: 10.1093/ijlct/ctz041.

LPKF Laser & Electronics, MicroLine 5000 UV laser system product flyer (system rating 6.5 kVA). REEL derivation of a per-package energy from that published rating and the system via rate, applied to the via count this process declares; no published document reports a per-package TMV-expose energy

Guste, Marinas & Ong, Machines 12 (2024) 467, Table 3; Besi Datacon 2200 evo product page
Background data: ecoinvent 3.12
Background dataset: electricity, medium voltage
Uncertainty: -66.3% / +145.7% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kWh

Ar Process gasg · -72% / +82.8%

Derivation basis: No retrievable public document identified

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: argon, liquid
Uncertainty: -72% / +82.8% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

N₂ Process gasg · -21.5% / +24.8%

Source citations: uwaterloo.ca (date not recorded). A. Pequegnat, J. Persic, M. Mayer, Y. Zhou, J. Hong, K. Ahn, "Effect of gas type and flow rate on Cu free air ball formation in thermosonic wire bonding", Microelectronics Reliability 51 (2011) 43-52, doi 10.1016/j.microrel.2010.02.023. PDF document.
Alfred Yeung, Ivy Sutiono, Jochen Milke (Heraeus Materials Technology), "Optimization of Free Air Ball Formation of Copper and Palladium Coated Copper Bonding Wires", Proceedings of IMAPS 2010, 43rd International Symposium on Microelectronics, pp. 000661 ff
Background data: ecoinvent 3.12
Background dataset: nitrogen, liquid
Uncertainty: -21.5% / +24.8% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

H₂ Process gasg · -40.1% / +80.1%

Derivation basis: No retrievable public document identified

The sources for this row are listed below.
Source citations: uwaterloo.ca (date not recorded). A. Pequegnat, J. Persic, M. Mayer, Y. Zhou, J. Hong, K. Ahn, "Effect of gas type and flow rate on Cu free air ball formation in thermosonic wire bonding", Microelectronics Reliability 51 (2011) 43-52, doi 10.1016/j.microrel.2010.02.023. PDF document.
Alfred Yeung, Ivy Sutiono, Jochen Milke (Heraeus Materials Technology), "Optimization of Free Air Ball Formation of Copper and Palladium Coated Copper Bonding Wires", Proceedings of IMAPS 2010, 43rd International Symposium on Microelectronics, pp. 000661 ff
Background data: ecoinvent 3.12
Background dataset: hydrogen, gaseous, low pressure
Uncertainty: -40.1% / +80.1% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Compressed air (tool) Process gasg · -33.4% / +66.6%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: compressed air, 700 kPa gauge
Uncertainty: -33.4% / +66.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Compressed air Process gasg · -1.2% / +1.7%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources below come from the manufacturing operations behind this row.
Source citations (specific to this process): Inherited, rolled up from the contributing process steps:

Hu et al. (2019). Analysis of energy efficiency improvement of high-tech fabrication plants. International Journal of Low-Carbon Technologies. DOI: 10.1093/ijlct/ctz041.
Background data: ecoinvent 3.12
Background dataset: compressed air, 700 kPa gauge
Uncertainty: -1.2% / +1.7% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

O₂ Process gasg · -60% / +100%

Derivation basis: No retrievable public document identified

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: oxygen, liquid
Uncertainty: -60% / +100% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Copper sulfate pentahydrate (electroless) Process chemicalg · -16.5% / +33%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: copper sulfate
Uncertainty: -16.5% / +33% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Copper anodes (pattern plating) Process chemicalg · -12.8% / +14.9%

Derivation basis: No retrievable public document identified (metric clarification; per-substrate mass derivation retained in notes)

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: copper, cathode
Uncertainty: -12.8% / +14.9% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Formaldehyde solution Process chemicalg · -24.9% / +25.6%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: formaldehyde
Uncertainty: -24.9% / +25.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Palladium chloride Process chemicalg · -45.5% / +36.4%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: proxy-mapped
Background dataset: palladium
Notes: Proxy mapping uses 60% of the material mass.
Uncertainty: -45.5% / +36.4% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Nickel sulfate hexahydrate Process chemicalg · -20% / +19.8%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: nickel sulfate
Uncertainty: -20% / +19.8% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Sodium hypophosphite Process chemicalg · ±25%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: proxy-mapped
Background dataset: sodium phosphate
Uncertainty: ±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Gold potassium cyanide Process chemicalg · -15.1% / +13.2%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: proxy-mapped
Background dataset: gold
Notes: Proxy mapping uses 68.4% of the material mass.
Uncertainty: -15.1% / +13.2% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Potassium permanganate Process chemicalg · -40.2% / +19.8%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: potassium permanganate
Uncertainty: -40.2% / +19.8% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Dry film photoresist Process chemicalg · ±25%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: proxy-mapped
Background dataset: methyl methacrylate
Uncertainty: ±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Cu plating bath (CuSO₄ + H₂SO₄) Process chemicalg · -33.3% / +50%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: proxy-mapped
Background dataset: copper sulfate
Uncertainty: -33.3% / +50% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Flux (no-clean) Process chemicalg · -60% / +100%

Derivation basis: Typical flux application

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: flux, for wave soldering
Uncertainty: -60% / +100% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Capillary underfill (epoxy) Process chemicalg · -33.3% / +50%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: epoxy resin insulator, SiO2
Uncertainty: -33.3% / +50% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Flux (water soluble) Process chemicalg · -40% / +100%

Derivation basis: Flux type for FOWLP solder ball attach

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: flux, for wave soldering
Uncertainty: -40% / +100% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Stencil cleaner (IPA) Process chemicalg · -50% / +100%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: isopropanol
Uncertainty: -50% / +100% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

BT resin (4-layer FC-BGA) Materialkg

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources for this row are listed below.
Source citations (dataset-level): Analog Devices. "Wafer Level Chip Scale Package (WLCSP)." AN-617
Yole Group. "Amkor's Advanced Packaging: A Closer Look." 2017
Keser, B., et al. "Board level reliability and surface mount assembly of 0.35mm and 0.3mm pitch wafer level packages." IEEE ECTC
Sharma, G., et al. "Solutions Strategies for Die Shift Problem in Wafer Level Compression Molding."
Medium. "Why is Fan-Out Wafer-Level Packaging (FOWLP) the Future." 2025
Strategic Market Research. "Semiconductor Packaging Industry Statistics."
Background data: proxy-mapped
Background dataset: glass fibre reinforced plastic, polyester resin, hand lay-up
Uncertainty: No range defined.
Unit: kg

Molding Compound Materialkg

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources for this row are listed below.
Source citations (dataset-level): Analog Devices. "Wafer Level Chip Scale Package (WLCSP)." AN-617
Yole Group. "Amkor's Advanced Packaging: A Closer Look." 2017
Keser, B., et al. "Board level reliability and surface mount assembly of 0.35mm and 0.3mm pitch wafer level packages." IEEE ECTC
Sharma, G., et al. "Solutions Strategies for Die Shift Problem in Wafer Level Compression Molding."
Medium. "Why is Fan-Out Wafer-Level Packaging (FOWLP) the Future." 2025
Strategic Market Research. "Semiconductor Packaging Industry Statistics."
Background data: ecoinvent 3.12
Background dataset: epoxy resin insulator, SiO2
Uncertainty: No range defined.
Unit: kg

Solder Balls Materialkg

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources for this row are listed below.
Source citations (dataset-level): Analog Devices. "Wafer Level Chip Scale Package (WLCSP)." AN-617
Yole Group. "Amkor's Advanced Packaging: A Closer Look." 2017
Keser, B., et al. "Board level reliability and surface mount assembly of 0.35mm and 0.3mm pitch wafer level packages." IEEE ECTC
Sharma, G., et al. "Solutions Strategies for Die Shift Problem in Wafer Level Compression Molding."
Medium. "Why is Fan-Out Wafer-Level Packaging (FOWLP) the Future." 2025
Strategic Market Research. "Semiconductor Packaging Industry Statistics."
Background data: composite
Background dataset: Modelled as a composite of its constituent materials.
Uncertainty: No range defined.
Unit: kg

Silver Materialkg · -7.2% / +50%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources for this row are listed below.
Source citations (dataset-level): Analog Devices. "Wafer Level Chip Scale Package (WLCSP)." AN-617
Yole Group. "Amkor's Advanced Packaging: A Closer Look." 2017
Keser, B., et al. "Board level reliability and surface mount assembly of 0.35mm and 0.3mm pitch wafer level packages." IEEE ECTC
Sharma, G., et al. "Solutions Strategies for Die Shift Problem in Wafer Level Compression Molding."
Medium. "Why is Fan-Out Wafer-Level Packaging (FOWLP) the Future." 2025
Strategic Market Research. "Semiconductor Packaging Industry Statistics."
Background data: ecoinvent 3.12
Background dataset: silver
Notes: From Silver-filled conductive epoxy (84.5% silver)
Uncertainty: -7.2% / +50% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Epoxy resin, liquid Materialkg · -7.2% / +50%

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources for this row are listed below.
Source citations (dataset-level): Analog Devices. "Wafer Level Chip Scale Package (WLCSP)." AN-617
Yole Group. "Amkor's Advanced Packaging: A Closer Look." 2017
Keser, B., et al. "Board level reliability and surface mount assembly of 0.35mm and 0.3mm pitch wafer level packages." IEEE ECTC
Sharma, G., et al. "Solutions Strategies for Die Shift Problem in Wafer Level Compression Molding."
Medium. "Why is Fan-Out Wafer-Level Packaging (FOWLP) the Future." 2025
Strategic Market Research. "Semiconductor Packaging Industry Statistics."
Background data: ecoinvent 3.12
Background dataset: epoxy resin, liquid
Notes: From Silver-filled conductive epoxy (15.5% epoxy)
Uncertainty: -7.2% / +50% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

BT resin (2-layer) Materialkg

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources for this row are listed below.
Source citations (dataset-level): Analog Devices. "Wafer Level Chip Scale Package (WLCSP)." AN-617
Yole Group. "Amkor's Advanced Packaging: A Closer Look." 2017
Keser, B., et al. "Board level reliability and surface mount assembly of 0.35mm and 0.3mm pitch wafer level packages." IEEE ECTC
Sharma, G., et al. "Solutions Strategies for Die Shift Problem in Wafer Level Compression Molding."
Medium. "Why is Fan-Out Wafer-Level Packaging (FOWLP) the Future." 2025
Strategic Market Research. "Semiconductor Packaging Industry Statistics."
Background data: proxy-mapped
Background dataset: glass fibre reinforced plastic, polyester resin, hand lay-up
Uncertainty: No range defined.
Unit: kg

Cu wire Materialkg

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources for this row are listed below.
Source citations (dataset-level): Analog Devices. "Wafer Level Chip Scale Package (WLCSP)." AN-617
Yole Group. "Amkor's Advanced Packaging: A Closer Look." 2017
Keser, B., et al. "Board level reliability and surface mount assembly of 0.35mm and 0.3mm pitch wafer level packages." IEEE ECTC
Sharma, G., et al. "Solutions Strategies for Die Shift Problem in Wafer Level Compression Molding."
Medium. "Why is Fan-Out Wafer-Level Packaging (FOWLP) the Future." 2025
Strategic Market Research. "Semiconductor Packaging Industry Statistics."
Background data: ecoinvent 3.12
Background dataset: copper, cathode
Uncertainty: No range defined.
Unit: kg

PoP Underfill Materialkg

Derivation basis: Calculated from per-operation consumption, operation counts, and manufacturing yield.

The sources for this row are listed below.
Source citations (dataset-level): Analog Devices. "Wafer Level Chip Scale Package (WLCSP)." AN-617
Yole Group. "Amkor's Advanced Packaging: A Closer Look." 2017
Keser, B., et al. "Board level reliability and surface mount assembly of 0.35mm and 0.3mm pitch wafer level packages." IEEE ECTC
Sharma, G., et al. "Solutions Strategies for Die Shift Problem in Wafer Level Compression Molding."
Medium. "Why is Fan-Out Wafer-Level Packaging (FOWLP) the Future." 2025
Strategic Market Research. "Semiconductor Packaging Industry Statistics."
Background data: ecoinvent 3.12
Background dataset: epoxy resin insulator, SiO2
Uncertainty: No range defined.
Unit: kg

Outputs and waste

Wastewater Wastewaterm3 · -54.8% / +72.4%

Derivation basis: Calculated from the water balance: fresh-water input minus evaporation.

No source is attached to this row.
Source citations: Not stated
Background data: carried, no background dataset
Background dataset: No treatment route recorded for this output.
Uncertainty: -54.8% / +72.4% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: m3

Copper in wastewater-treatment sludge/recovery Solid wasteg · -2.9% / +3.1%

Source citations (dataset-level): mee.gov.cn (date not recorded). GB 39731-2020, Emission standard of water pollutants for the electronics industry (official MEE PDF) - Table 1 item 13 total copper 0.5 direct / 2.0 indirect mg/L; Table 2 benchmark effluent volumes per wafer / per m2 PCB / per package. Standard.
gazette.nat.gov.tw (date not recorded). Executive Yuan Gazette Vol. 030 No. 237, 2024-12-18 - amendment to Taiwan Effluent Standards; Attached Table 1 (wafer/semiconductor) and Table 5 (basic metal / surface treatment / electroplating / PCB) copper ladder 3.0 -> 2.0 -> 1.5 -> 1.0 mg/L by vintage and permitted flow. PDF document.
epa.gov (date not recorded). U.S. EPA Office of Water, "Preliminary Study of the Electrical and Electronic Components Point Source Category", EPA-821-R-22-005, DCN 11197 (2022) - Table 12 indirect Cu median 0.05 / mean 0.213 / max 5.64 / min 0.00015 mg/L (67 facilities, 1,309 results, 996 detects); Table 13 direct; Table 6 named-facility treatment trains; sec. 1.2.3.1 post-1983 process additions. Government report.
Source citations (dataset-level): Inherited from this dataset's own bibliography, not tied to this row:

epa.gov (date not recorded). U.S. EPA Office of Water, "Preliminary Study of the Electrical and Electronic Components Point Source Category", EPA-821-R-22-005, DCN 11197 (2022) - Table 12 indirect Cu median 0.05 / mean 0.213 / max 5.64 / min 0.00015 mg/L (67 facilities, 1,309 results, 996 detects); Table 13 direct; Table 6 named-facility treatment trains; sec. 1.2.3.1 post-1983 process additions. Government report.

mee.gov.cn (date not recorded). GB 39731-2020, Emission standard of water pollutants for the electronics industry (official MEE PDF) - Table 1 item 13 total copper 0.5 direct / 2.0 indirect mg/L; Table 2 benchmark effluent volumes per wafer / per m2 PCB / per package. Standard.

gazette.nat.gov.tw (date not recorded). Executive Yuan Gazette Vol. 030 No. 237, 2024-12-18 - amendment to Taiwan Effluent Standards; Attached Table 1 (wafer/semiconductor) and Table 5 (basic metal / surface treatment / electroplating / PCB) copper ladder 3.0 -> 2.0 -> 1.5 -> 1.0 mg/L by vintage and permitted flow. PDF document.
Background data: ecoinvent 3.12 treatment route
Background dataset: market for copper scrap, sorted, pressed
Uncertainty: -2.9% / +3.1% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Spent dry film resist Solid wasteg · ±25%

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of waste plastic, mixture, municipal incineration
Uncertainty: ±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Manganate desmear sludge Solid wasteg · -40% / +35%

Source citations (dataset-level): rsc.org. Heterointerfacial adhesion failure mechanism of ultrahigh filler loading containing epoxy composite films for chip substrates.
tekhpolis.ru (date not recorded). S7439 PROCESS GUIDELINES. PDF document.
Source citations (dataset-level): Inherited from this dataset's own bibliography, not tied to this row:

rsc.org. Heterointerfacial adhesion failure mechanism of ultrahigh filler loading containing epoxy composite films for chip substrates.

tekhpolis.ru (date not recorded). S7439 PROCESS GUIDELINES. PDF document.
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, underground deposit
Uncertainty: -40% / +35% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Solder mask develop sludge (unpolymerized resin) Solid wasteg · -34.8% / +30.4%

Derivation basis: No retrievable public document identified

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of waste plastic, mixture, municipal incineration
Uncertainty: -34.8% / +30.4% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Phosphorus in wastewater-treatment sludge Solid wasteg · -47% / +46.6%

Derivation basis: Derived: elemental phosphorus balance, the phosphorus reaching treatment less the post-treatment residual

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, underground deposit
Uncertainty: -47% / +46.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Spent photoresist (liquid spin-off) Solid wasteg · -33.8% / +386.5%

Source citations: microsi.com (date not recorded). Flack, W.W., Nguyen, H.-A. (Ultratech), Capsuto, E. (Shin-Etsu MicroSi), Abreau, K. (STEAG Hamatech USA), "Characterization of 100 Micron Thick Positive Photoresist on 300 mm Wafers", SPIE 2005 #5753-103. PDF document.
nrf.aux.eng.ufl.edu (date not recorded). AZ 9260 PHOTORESIST (520CPS) (US) Material Safety Data Sheet, substance key SXR109902, revision date 03/03/2010. PDF document.
epa.gov (date not recorded). US EPA, Emission Inventory Improvement Program (EIIP) Volume II, Chapter 6: Preferred and Alternative Methods for Estimating Air Emissions from Semiconductor Manufacturing, 2/24/99. PDF document.
rcrapublic.epa.gov (date not recorded). US EPA RCRA Online RO 11249, memorandum 9444.1987(18), letter to Mr. Frank Czigler, S & W Waste Inc., dated MAY 20 1987. PDF document.
pmc.ncbi.nlm.nih.gov (date not recorded). Ni, J., Zhang, Q., Zhang, X., Sun, Z., Bao, D., "Detection Method and Common Characteristics of Waste Solvent from Semiconductor Industry", Molecules 28(16):5992, 2023. Journal article.
epa.gov (date not recorded). US EPA, "Defining Hazardous Waste: Listed, Characteristic and Mixed Radiological Wastes".
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, hazardous waste incineration, with energy recovery
Uncertainty: -33.8% / +386.5% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Photoresist solids in NMP strip bath Solid wasteg · -33.2% / +66.8%

Source citations: microsi.com (date not recorded). Flack, W.W., Nguyen, H.-A. (Ultratech), Capsuto, E. (Shin-Etsu MicroSi), Abreau, K. (STEAG Hamatech USA), "Characterization of 100 Micron Thick Positive Photoresist on 300 mm Wafers", SPIE 2005 #5753-103. PDF document.
nrf.aux.eng.ufl.edu (date not recorded). AZ 9260 PHOTORESIST (520CPS) (US) Material Safety Data Sheet, substance key SXR109902, revision date 03/03/2010. PDF document.
rcrapublic.epa.gov (date not recorded). US EPA RCRA Online RO 11249, memorandum 9444.1987(18), letter to Mr. Frank Czigler, S & W Waste Inc., dated MAY 20 1987. PDF document.
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, hazardous waste incineration, with energy recovery
Uncertainty: -33.2% / +66.8% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Mixed process waste Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

EMC debris Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

Grinding slurry Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

The sources below come from the manufacturing operations behind this row.
Source citations (specific to this process): Inherited, rolled up from the contributing process steps:

Hu et al. (2019). Analysis of energy efficiency improvement of high-tech fabrication plants. International Journal of Low-Carbon Technologies. DOI: 10.1093/ijlct/ctz041.

Alfred Yeung, Ivy Sutiono, Jochen Milke (Heraeus Materials Technology), "Optimization of Free Air Ball Formation of Copper and Palladium Coated Copper Bonding Wires", Proceedings of IMAPS 2010, 43rd International Symposium on Microelectronics, pp. 000661 ff

uwaterloo.ca (date not recorded). A. Pequegnat, J. Persic, M. Mayer, Y. Zhou, J. Hong, K. Ahn, "Effect of gas type and flow rate on Cu free air ball formation in thermosonic wire bonding", Microelectronics Reliability 51 (2011) 43-52, doi 10.1016/j.microrel.2010.02.023. PDF document.

IPCC 2019 Guidelines Vol 3 Ch 6

EPA 40 CFR Part 98 Subpart I (2024)
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, underground deposit
Uncertainty: No range defined.
Unit: g

EMC flash/cull Solid wasteg

Derivation basis: Calculated from material efficiency

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

Flux residue on stencil Solid wasteg

Derivation basis: Calculated from the mass balance of spent materials and consumables, with treatment selected from the waste classification.

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, hazardous waste incineration, with energy recovery
Uncertainty: No range defined.
Unit: g

Broken dies Solid wasteg

Derivation basis: Engineering estimate based on yield loss

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

Uncured Ag-filled die-attach epoxy (dispense loss) Solid wasteg · -72.2% / +500%

Source citations: seipi.org.ph (date not recorded). Amalin, M.S. (STMicroelectronics Calamba), "Challenging the Process and Material Characteristic to Address the High Epoxy Usage/Consumption of VI Power Packages", 32nd ASEMEP National Technical Symposium. Symposium paper.
musashi-engineering.de (date not recorded). Musashi Engineering, "SuperSigma CM IV" fully digital controlled dispenser catalogue, CAT. No.SuperSigmaCMIV-12231-E-COPY (Nov 2023). Vendor catalogue.
irjaes.com (date not recorded). Capili, M.D. (STMicroelectronics Calamba), "Comparative Analysis for Die Attach Dispensing Methods", Int. Research Journal of Advanced Engineering and Science, Vol.4 Issue 4, pp.170-172, 2019. PDF document.
datasheets.tdx.henkel.com (date not recorded). Henkel, LOCTITE ABLESTIK 84-1LMI Technical Data Sheet, Oct 2014. Technical data sheet.
datasheets.tdx.henkel.com (date not recorded). Henkel, LOCTITE ABLESTIK ABP 2025DNP Technical Data Sheet, Jan 2025. Technical data sheet.
seipi.org.ph (date not recorded). Cantos, Lopez & Wagan (STMicroelectronics Calamba OPS2), "A Six Sigma Approach to Address High PPM at Die Attach Due to Epoxy Related Rejects", 34th ASEMEP National Technical Symposium. Symposium paper.
Machine Capability Enhancement to Address Lacking Epoxy Coverage During Die Attach Process of QFN Packages", J. Engineering Research and Reports ms JERR_88623, publisher-hosted preprint (UNDER PEER REVIEW watermark)
seipi.org.ph (date not recorded). Villarico, De La Rosa & Cuchapin (Texas Instruments Philippines, Baguio), "Automated Dispense Nozzle Cleaning Machine: TI Inside", 31st ASEMEP National Technical Symposium. Symposium paper.
mm.digikey.com (date not recorded). Henkel, SDS LOCTITE ABLESTIK 2902-R (TRA-DUCT 2902-R), issue 11/11/2019. Safety data sheet.
caplinq.com (date not recorded). Henkel, SDS LOCTITE ABLESTIK 3888 TPK, SDS No. 542703 V003.0, revision 17.04.2020 (Caplinq-hosted). Safety data sheet.
Background data: ecoinvent 3.12 treatment route
Background dataset: market for precious metal from electronics scrap, in anode slime
Uncertainty: -72.2% / +500% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Emissions to air

8 elementary flows released to air by this dataset's own operations. Quantities are not published; they ship with the dataset on Circa.

Volatile organic compounds (VOCs) Emission to airg

Derivation basis: Calculated as an air release, from a mass balance on the process gases going in, with the destruction or removal efficiency of any point-of-use abatement applied.

No source is attached to this row.
Source citations: Not stated
Compartment: Air (non-urban air or from high stacks)
ecoinvent 3.12 elementary flow: NMVOC, non-methane volatile organic compounds
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

HCHO Emission to airg

Derivation basis: Calculated as an air release, from a mass balance on the process gases going in, with the destruction or removal efficiency of any point-of-use abatement applied.

No source is attached to this row.
Source citations: Not stated
Compartment: Air (non-urban air or from high stacks)
CAS number: 50-00-0
ecoinvent 3.12 elementary flow: Formaldehyde
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Flux volatiles Emission to airg

Derivation basis: Calculated as an air release, from a mass balance on the process gases going in, with the destruction or removal efficiency of any point-of-use abatement applied.

No source is attached to this row.
Source citations: Not stated
Compartment: Air (non-urban air or from high stacks)
ecoinvent 3.12 elementary flow: NMVOC, non-methane volatile organic compounds
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

VOCs (from underfill cure) Emission to airg

Derivation basis: Calculated as an air release, from a mass balance on the process gases going in, with the destruction or removal efficiency of any point-of-use abatement applied.

No source is attached to this row.
Source citations: Not stated
Compartment: Air (non-urban air or from high stacks)
ecoinvent 3.12 elementary flow: NMVOC, non-methane volatile organic compounds
Uncertainty: No range defined.
Unit: g

Particulates (EMC ablation) Emission to airg

Derivation basis: Calculated as an air release, from a mass balance on the process gases going in, with the destruction or removal efficiency of any point-of-use abatement applied.

No source is attached to this row.
Source citations: Not stated
Compartment: Air (non-urban air or from high stacks)
ecoinvent 3.12 elementary flow: Particulate Matter, < 2.5 um
Uncertainty: No range defined.
Unit: g

VOCs (from epoxy cure) Emission to airg

Source citations: etd.gsfc.nasa.gov (date not recorded). NASA Goddard Space Flight Center, Engineering and Technology Directorate, "Outgassing Data for Selecting Spacecraft Materials" online database, complete CSV export (13,582 records; ASTM E595 total mass loss, collected volatile condensable material and water vapour regained by material, manufacturer and application).
etd.gsfc.nasa.gov (date not recorded). NASA Goddard Space Flight Center, Engineering and Technology Directorate, "Outgassing Database - User Guide" (ASTM E595 apparatus and conditions, TML / CVCM / WVR definitions, and the low-outgassing pass criteria).
Compartment: Air (non-urban air or from high stacks)
ecoinvent 3.12 elementary flow: NMVOC, non-methane volatile organic compounds
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

VOCs (from EMC cure) Emission to airg

Derivation basis: Engineering estimate based on EMC composition

No source is attached to this row.
Source citations: Not stated
Compartment: Air (non-urban air or from high stacks)
ecoinvent 3.12 elementary flow: NMVOC, non-methane volatile organic compounds
Uncertainty: No range defined.
Unit: g

Particulates (marking fume) Emission to airg

Derivation basis: Estimated from mold compound ablation

No source is attached to this row.
Source citations: Not stated
Compartment: Air (non-urban air or from high stacks)
ecoinvent 3.12 elementary flow: Particulate Matter, < 2.5 um
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Emissions to water

7 elementary flows released to water by this dataset's own operations. Quantities are not published; they ship with the dataset on Circa.

Cu2+ Emission to waterg

Source citations: mee.gov.cn (date not recorded). GB 39731-2020, Emission standard of water pollutants for the electronics industry (official MEE PDF) - Table 1 item 13 total copper 0.5 direct / 2.0 indirect mg/L; Table 2 benchmark effluent volumes per wafer / per m2 PCB / per package. Standard.
epa.gov (date not recorded). U.S. EPA Office of Water, "Preliminary Study of the Electrical and Electronic Components Point Source Category", EPA-821-R-22-005, DCN 11197 (2022) - Table 12 indirect Cu median 0.05 / mean 0.213 / max 5.64 / min 0.00015 mg/L (67 facilities, 1,309 results, 996 detects); Table 13 direct; Table 6 named-facility treatment trains; sec. 1.2.3.1 post-1983 process additions. Government report.
gazette.nat.gov.tw (date not recorded). Executive Yuan Gazette Vol. 030 No. 237, 2024-12-18 - amendment to Taiwan Effluent Standards; Attached Table 1 (wafer/semiconductor) and Table 5 (basic metal / surface treatment / electroplating / PCB) copper ladder 3.0 -> 2.0 -> 1.5 -> 1.0 mg/L by vintage and permitted flow. PDF document.
Compartment: Water (surface water)
Formula: Cu
CAS number: 7440-50-8
ecoinvent 3.12 elementary flow: Copper ion
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Ni Emission to waterg

Derivation basis: Calculated as a release to water, from a contaminant mass balance on the process chemistry.

No source is attached to this row.
Source citations: Not stated
Compartment: Water (surface water)
Formula: Ni2+
CAS number: 14701-22-5
ecoinvent 3.12 elementary flow: Nickel II
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

CN- Emission to waterg

Derivation basis: Calculated as a release to water, from a contaminant mass balance on the process chemistry.

No source is attached to this row.
Source citations: Not stated
Compartment: Water (surface water)
CAS number: 57-12-5
ecoinvent 3.12 elementary flow: Cyanide
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Phosphorus (from hypophosphite) Emission to waterg

Source citations: EU STM BREF 2006 §2.13.1.13 and §4.16.9.2; EPA E&EC Study Report 2022 Table 13
Compartment: Water (surface water)
Formula: P
CAS number: 7723-14-0
ecoinvent 3.12 elementary flow: Phosphorus
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Sn2+ Emission to waterg

Source citations: p2infohouse.org (date not recorded). Florida Pollution Prevention Program - Electroplating Tip Sheet: Drag-Out Reduction (2000). Report.
p2infohouse.org (date not recorded). Florida Pollution Prevention Program - Electroplating Tip Sheet: Rinse Water Reduction (2000). Report.
Park et al. - Effects of the degradation of methane sulfonic acid electrolyte on the collapse failure of Sn-Ag alloy solders for flip-chip interconnections, RSC Advances, 2017
Compartment: Water (surface water)
Formula: Sn
CAS number: 7440-31-5
ecoinvent 3.12 elementary flow: Tin ion
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Ammonium Emission to waterg

Source citations: p2infohouse.org (date not recorded). Florida Pollution Prevention Program - Electroplating Tip Sheet: Drag-Out Reduction (2000). Report.
p2infohouse.org (date not recorded). Florida Pollution Prevention Program - Electroplating Tip Sheet: Rinse Water Reduction (2000). Report.
Park et al. - Effects of the degradation of methane sulfonic acid electrolyte on the collapse failure of Sn-Ag alloy solders for flip-chip interconnections, RSC Advances, 2017
Compartment: Water (surface water)
Formula: NH4+
CAS number: 14798-03-9
ecoinvent 3.12 elementary flow: Ammonium
Notes: TMAH biodegrades in WWTP; NH4+ mass fraction 18.04/91.15
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Dissolved organics (COD) Emission to waterg

Source citations: p2infohouse.org (date not recorded). Florida Pollution Prevention Program - Electroplating Tip Sheet: Drag-Out Reduction (2000). Report.
p2infohouse.org (date not recorded). Florida Pollution Prevention Program - Electroplating Tip Sheet: Rinse Water Reduction (2000). Report.
Park et al. - Effects of the degradation of methane sulfonic acid electrolyte on the collapse failure of Sn-Ag alloy solders for flip-chip interconnections, RSC Advances, 2017
Compartment: Water (surface water)
ecoinvent 3.12 elementary flow: COD, Chemical Oxygen Demand
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

Flows not quantified

1 flow is recorded for this dataset but carries no quantity — cut off below the significance threshold, or with no background dataset available. It remains inside the declared system boundary; each is listed with its reason.

Cut off - below the significance threshold (1)

SnAg plating bath (MSA-based) Process chemicalg · -40% / +60%

Derivation basis: Solder plating bath

No source is attached to this row.
Source citations: Not stated
Background data: cut off
Background dataset: Not applicable: this flow is not quantified in the inventory.
Reason: The tin-silver plating bath is consumed in trace quantity and its formulation is complex, recorded in this inventory. This row covers the bath chemistry alone; the tin and silver the bath deposits onto the package are not carried on it. Where this dataset lists no separate deposited-solder material row, the deposited tin and silver are absent from the dataset altogether rather than accounted for elsewhere, and whether they belong inside this boundary is an open question this record does not settle. The bath chemistry falls below the declared cut-off threshold, so no upstream production dataset is attached.
Uncertainty: -40% / +60% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Limitations and unquantified flows (5)

Limits this dataset declares about itself: first any limit stated in its own description, then any limit it declares flow by flow, grouped by channel. Each entry below is the model's own disclosure.

The die-attach adhesive on this dataset is booked from the retained mass declared for the stacked memory dies of the upper package, grossed up by the dispense loss its die-attach process file records, and split into silver and epoxy by the composition the material registry holds for silver-filled paste. Two limitations follow. The declared retained mass is an engineering estimate stated for the pair of dies together rather than derived from their area and their bond line. And the silver fraction applied is the registry's own for this class of paste, not the fraction this bill states beside the mass, so the split between the metal and the resin is the registry's rather than this package's.
The nitrogen, compressed air and ultrapure water used by the through-mould-via exposure step are engineering estimates with no supporting source. They were reviewed on 1 September 2026 alongside that step's electricity, which was re-derived from a published laser system rating; no comparable figure could be found for the gases or the rinse water, so their values were left unchanged rather than replaced by a guess, and their quality rating was lowered instead. They are a large share of this dataset's compressed air in particular. Treat all three as indicative.
These materials are used at a step of the modelled flow and are also carried by this dataset's own material list. Each is counted once, on that list, and the step does not book it again: AP die bump (flip-chip) uses Copper (anode or replenishment) and SnAg solder; Ball attach (bottom) uses SAC305 solder balls; Wire bonding uses Copper wire (Cu); Ball attach (top-side) uses SAC305 solder balls; PoP reflow uses SAC305 solder balls; DRAM die attach uses Die attach epoxy (Ag-filled conductive); Top package mold uses Epoxy Mold Compound (EMC).
Where the process record behind a step offers a choice of material, the modelled flow takes the one this dataset's own material list carries, and the entries it does not select are not added: Wire bonding takes copper wire from that list, not Gold wire (Au).
Some consumable pulls referenced by the modelled process steps did not resolve to an inventory row and are absent from this dataset. They are itemised in the dataset's own export audit.

The flows above are this dataset's own records. What follows are the scope rules set once for the whole database in the methodology report, repeated here so every dataset page carries them.

Database-wide boundary policy — applies to every REEL dataset

These boundaries are set once for the whole database, in Chapter 2 of the methodology report, and apply to this dataset wherever they are relevant to it. The excluded flows listed above are specific to this dataset.

Use phase: Product operation is outside the cradle-to-gate scope.
End-of-life treatment: Recycling and disposal are outside the cradle-to-gate scope.
Distribution and retail: The gate is a finished component ready for integration into a higher-level assembly.
Inbound transport of raw materials: Transport of purchased raw materials to the manufacturing facility is already inside the upstream "market for" datasets that users link to a background database, so it is not modelled a second time here. This does not cover freight between REEL production stages, which is modelled where a dataset authors it.
Returnable shipping containers: Where freight between production stages is modelled, the mass moved is the product itself. The shipping container (FOSB, SEMI M31) is returnable capital equipment whose per-trip share is unsourced, so its tare is excluded from the transport effort.
Photomask fabrication: A mask set's embodied burden is amortised across a high-volume production run and is not attributed per wafer. Users assessing low-volume production should add mask fabrication separately; the methodology report gives the basis for the exclusion.
Employee transport, administration and R&D overhead: Employee transportation, facility administration and R&D/pilot-production overhead are outside scope.
Capital goods: Manufacturing equipment, cleanroom construction and facility infrastructure are excluded, on the grounds of absent public data on equipment embodied energy, uncertainty in equipment lifetime and allocation, common practice in electronics LCA, and a focus on the operational inventory. Future versions may include capital goods when sufficient public data becomes available.
Precious metal recovery credits: Scrap recovery credits for precious metals are excluded pending data availability.
Wafer reclaim: Test wafers and scrap are outside the system boundary.

Inside the boundary, linked rather than modelled

Silicon ingot growth and wafer slicing: Inside the cradle-to-gate scope, but treated as upstream material inputs linked to background databases rather than modelled as REEL processes.
Freight between production stages: Where a dataset's product moves between REEL production stages - wafer fabrication to the packaging site, for example - that leg is authored as a transport service and linked to an ecoinvent freight activity. It is measured as a transport effort in tonne-kilometres, not as a mass. Route distances are authored per route class with a stated band; a lower bound of zero is a modelling statement that the two sites can be co-located, not a missing value.

Cut-off criteria

A flow is excluded from a process inventory when it contributes less than 1 % of the total mass of inputs to that unit process, or less than 1 % of its total energy input. The denominator is total process inputs, not product mass. That distinction matters in semiconductor manufacturing, where the input mass of water, chemicals and gases greatly exceeds the product mass, so the threshold removes only genuinely minor flows.

Included regardless of the cut-off

Perfluorocarbons (CF4, C2F6, SF6, NF3) - high GWP, EPA regulated
Heavy metals (Pb, Cd, Hg, Cr(VI)) - RoHS regulated, high toxicity
Volatile organics (photoresist solvents, PGMEA) - air quality
Precious metals (Au, Ag, Pd, Pt) - high embodied impacts
Ozone-depleting substances (legacy CFCs, HCFCs) - Montreal Protocol