Overview

General comment

Production covered

System boundary: covers TSV formation, stacking, molding, and stack-level test of the memory stack itself. Silicon interposer, 2.5D redistribution, and organic package substrate are deliberately excluded - owned by the consuming 2.5D-packaging dataset under the count-once convention. Accelerator/module-level assembly is outside this boundary and is not modeled in REEL v1.0. 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.

This variant represents an 8-high die stack.

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: HBM3-TSV, 3D stacked memory
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 2.1 Good

Reliability

2.4

Completeness

2.7

Temporal

2.1

Geographic

2.2

Technological

1.3

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: 13 — the source records behind this dataset's manufacturing operations. Each carries the five pedigree axes above; the composite DQI aggregates them.

Technosphere inputs

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

SF₆ production Process gasg · ±33.6%

Derivation basis: Calculated from SF6 etch flow and TSV etch energy per wafer

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: ±33.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

C₄F₈ production Process gasg · ±33.5%

Derivation basis: Calculated from C4F8 passivation flow and TSV etch energy per wafer

No source is attached to this row.
Source citations: Not stated
Upstream REEL dataset: Octafluorocyclobutane (c-C4F8)
Background dataset: Modelled by REEL; see the upstream dataset above.
Uncertainty: ±33.5% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

CMP Slurry (Copper) Process chemicalg · -27.8% / +33.2%

Derivation basis: Calculated from barrier removal rate

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:

link.springer.com (date not recorded). Approaches to Sustainability in CMP: A Review. Journal article. DOI: 10.1007/s40684-021-00406-8.

nccavs-usergroups.avs.org (2024). Reducing CMP Process Mass Intensity. PDF document.

sciencedirect.com. Silica-Based Slurry - an overview.

pall.com (date not recorded). Wastewater Treatment in Semiconductor Industry. PDF document.
Upstream REEL dataset: Copper CMP Slurry
Background dataset: Modelled by REEL; see the upstream dataset above.
Uncertainty: -27.8% / +33.2% 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% / +32.9%

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% / +32.9% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Water supply (municipal) Waterm3 · -34.3% / +52.7%

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: -34.3% / +52.7% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: m3

Electricity, Taiwan (TW) ElectricitykWh · -58.3% / +94.8%

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.

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

limitekltd.com (date not recorded). EBARA F-REX 300S - Limitek used-equipment listing (EB023), including photographs of the tool rating plate. PDF document.

fabsurplus.com (date not recorded). EBARA CMP SPEC <F-REX300S> - Ebara-authored configuration/checklist sheet, SDI (fabsurplus) catalogue item 82844.

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.

Disco Corporation DFD6361 dicing saw specifications (blade-dicing process power and wafer throughput)
Background data: ecoinvent 3.12
Background dataset: electricity, medium voltage
Uncertainty: -58.3% / +94.8% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kWh

Ar Process gasg · -40% / +60.1%

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: argon, liquid
Uncertainty: -40% / +60.1% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

N₂ Process gasg · ±17.9%

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: nitrogen, liquid
Uncertainty: ±17.9% 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 · -40% / +60%

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: -40% / +60% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Copper (TSV electroplated fill) Process chemicalg · -30% / +40%

Derivation basis: Calculated from copper fill for through-silicon vias per wafer

No source is attached to this row.
Source citations: Not stated
Background data: ecoinvent 3.12
Background dataset: copper, cathode
Uncertainty: -30% / +40% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Cu plating bath (CuSO₄ + H₂SO₄) Process chemicalg · -33.3% / +50.1%

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% / +50.1% 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

SAC305 Materialkg · -29.4% / +282.4%

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: composite
Background dataset: Modelled as a composite of its constituent materials.
Uncertainty: -29.4% / +282.4% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Outputs and waste

Wastewater Wastewaterm3 · -34.3% / +52.7%

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: -34.3% / +52.7% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: m3

CMP slurry waste Solid wasteg · -27.8% / +33.2%

Derivation basis: Copper bulk, barrier and buff slurry (the dispensed-volume input rows on this record)

The sources below are this dataset's own bibliography. They are not tied to this row.
Source citations (dataset-level): Inherited from this dataset's own bibliography, not tied to this row:

link.springer.com (date not recorded). Approaches to Sustainability in CMP: A Review. Journal article. DOI: 10.1007/s40684-021-00406-8.

nccavs-usergroups.avs.org (2024). Reducing CMP Process Mass Intensity. PDF document.

sciencedirect.com. Silica-Based Slurry - an overview.

pall.com (date not recorded). Wastewater Treatment in Semiconductor Industry. PDF document.
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, underground deposit
Uncertainty: -27.8% / +33.2% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Copper in wastewater-treatment sludge/recovery Solid wasteg

Source citations (dataset-level): 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.
Background data: ecoinvent 3.12 treatment route
Background dataset: market for copper scrap, sorted, pressed
Uncertainty: No range defined.
Unit: g

Spent CMP pads Solid wasteg · -51.8% / +678.7%

Derivation basis: REEL derivation: CMP pad mass from pad geometry and polyurethane density

The sources for this row are listed below.
Source citations: Pureon AG (2024). Pureon IC1000 and IC1010 CMP Polishing Pads - Product Datasheet. Pureon product datasheet; IC1000 and IC1010 are DuPont trademarks.
Chu-An Lee; Hui-Chi Huang; Peng-Chung Jangjian (2013). US 8,367,429 B2: Adaptive endpoint method for pad life effect on chemical mechanical polishing. United States Patent and Trademark Office.
Technological Breakthrough in Pad Life Improvement and its Impact on CMP CoC.
pmc.ncbi.nlm.nih.gov (date not recorded). Approaches to Sustainability in Chemical Mechanical Polishing (CMP): A Review. Journal article.
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of hazardous waste, underground deposit
Uncertainty: -51.8% / +678.7% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Mixed process waste Solid wasteg · -0.8% / +0.9%

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
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: -0.8% / +0.9% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Spent photoresist (liquid spin-off) Solid wasteg · -33.8% / +385.1%

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% / +385.1% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Photoresist solids in NMP strip bath Solid wasteg · -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.
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: -33.4% / +66.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Silicon Kerf Solid wasteg · ±25%

Source citations: Semiconductor Digest, reported blade-dicing kerf width
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: ±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Silicon Cake From Treatment Solid wasteg

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
Background data: ecoinvent 3.12 treatment route
Background dataset: treatment of inert waste, sanitary landfill
Uncertainty: No range defined.
Unit: g

Grinding slurry waste 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 inert waste, sanitary landfill
Uncertainty: ±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

EMC flash/excess Solid wasteg · ±33.3%

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: ±33.3% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Release film 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 inert waste, sanitary landfill
Uncertainty: ±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Emissions to air

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

SF₆ Emission to airg

Derivation basis: Calculated from the sulfur hexafluoride purchased for this step and the central gas-fate utilisation and destruction-removal efficiency for thermal abatement

No source is attached to this row.
Source citations: Not stated
Compartment: Air (non-urban air or from high stacks)
CAS number: 2551-62-4
ecoinvent 3.12 elementary flow: Sulfur hexafluoride
Uncertainty: A minimum-maximum range is defined for this flow. Bounds ship with the dataset on Circa.
Unit: g

C₄F₈ Emission to airg

Derivation basis: Calculated from the octafluorocyclobutane purchased for this step and the central gas-fate utilisation and destruction-removal efficiency for thermal abatement

No source is attached to this row.
Source citations: Not stated
Compartment: Air (non-urban air or from high stacks)
CAS number: 115-25-3
ecoinvent 3.12 elementary flow: Tetrafluoromethane
Notes: Proxied to CF4 (Tetrafluoromethane) for ecoinvent linking. The two substances are not equivalent: this one has the substantially greater warming effect of the pair, so any characterization performed through this proxy link understates it. Use the substance's own factor rather than the proxy's.
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

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: No range defined.
Unit: g

Emissions to water

5 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: 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.
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

Si 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)
CAS number: 7440-21-3
ecoinvent 3.12 elementary flow: Silicon
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

2 flows are recorded for this dataset but carry no quantity — cut off below the significance threshold, or with no background dataset available. They remain 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

Not quantified - no background dataset available (1)

Release film 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: no background dataset
Background dataset: Not applicable: this flow is not quantified in the inventory.
Reason: A single-use polymer film laid between the stack and the bonding tool so the two release cleanly, discarded after one use. No release-film production activity exists in the background database used for linkage, no supporting publication for this consumable was identified, and no material composition was found for it, so nothing is asserted about what it is made of. A protective liner for thermal pads is mapped in this inventory and is the nearest thing to it, but the two are not confirmed to be the same film, and attaching one product's burden to another on a resemblance would state more than is known. It is carried as a declared gap instead.
Uncertainty: ±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Limitations and unquantified flows (3)

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 uncertainty range on this dataset's abated fluorinated-gas emissions to air is the range of the incoming gas, carried through in proportion. It does not widen for how much of the gas is consumed in the reaction, or for how completely the abatement destroys what is left; both of those are held at their central values on this dataset. Wafer datasets do carry those two through into the range, so the range published here is narrower than the one a wafer dataset publishes for the same kind of emission.
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: Cu pillar + SnAg cap plating, non-UBM remainder (allocated per stack) uses SnAg solder; Ball attach and reflow uses SAC305 solder balls.
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