Overview

General comment

Production covered

Fan-out wafer-level package: dies are placed face-down on a carrier and molded into a reconstituted wafer, on which the redistribution wiring and solder balls are then built. 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: FOWLP
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 1.7 Very good

Reliability

2.7

Completeness

1.7

Temporal

1.3

Geographic

2.0

Technological

1.2

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

Technosphere inputs

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

TMAH Developer (2.38% solution) Process chemicalg · -40% / +50%

Derivation basis: Equipment vendor typical

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: -40% / +50% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Water supply (municipal) Waterm3 · -33.3% / +55.1%

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: -33.3% / +55.1% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: m3

Electricity, Taiwan (TW) ElectricitykWh · -49.6% / +60.6%

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:

CAE Online: Teradyne Catalyst Specifications

EE Journal: "Advantest Unveils New Ultra-High-Current Power Supply" (2024)

4Semi: TEL Precio Wafer Prober Specifications

FormFactor Summit 11000/12000 Facility Planning Guide

3D InCites: "ERS Electronic Introduces High Power Dissipation Thermal Chuck" (2023)

Abachy: "How Much Energy and Water Are Required for Wafer Fabrication" (2025)

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: -49.6% / +60.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kWh

N₂ Process gasg · -37.2% / +43.9%

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: -37.2% / +43.9% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Compressed air Process gasg · -30.2% / +39.5%

Source citations: CAE Online: Teradyne Catalyst Specifications
EE Journal: "Advantest Unveils New Ultra-High-Current Power Supply" (2024)
4Semi: TEL Precio Wafer Prober Specifications
FormFactor Summit 11000/12000 Facility Planning Guide
3D InCites: "ERS Electronic Introduces High Power Dissipation Thermal Chuck" (2023)
Abachy: "How Much Energy and Water Are Required for Wafer Fabrication" (2025)
Background data: ecoinvent 3.12
Background dataset: compressed air, 700 kPa gauge
Uncertainty: -30.2% / +39.5% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Ar Process gasg · ±76.5%

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: ±76.5% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Cu plating bath (CuSO₄ + H₂SO₄) Process chemicalg · -33.3% / +33.4%

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: copper sulfate
Uncertainty: -33.3% / +33.4% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Photoresist stripper (NMP-based) Process chemicalg · -40% / +60%

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: N-methyl-2-pyrrolidone
Uncertainty: -40% / +60% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Flux (water soluble) Process chemicalg · -40% / +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: flux, for wave soldering
Uncertainty: -40% / +100% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

EMC Added 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

RDL Cu 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

Solder Balls Materialkg · -31.9% / +40.5%

Source citations: thor.inemi.org (date not recorded). IPC/EIA J-STD-032, Performance Standard for Ball Grid Array Balls, Table 1, October 2000. Industry standard.
Background data: composite
Background dataset: Modelled as a composite of its constituent materials.
Uncertainty: -31.9% / +40.5% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: kg

Outputs and waste

Wastewater Wastewaterm3 · -33.3% / +55.1%

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: -33.3% / +55.1% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: m3

Spent adhesive 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, underground deposit
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

EMC flash/excess Solid wasteg · -24.7% / +25.3%

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: -24.7% / +25.3% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Release film Solid wasteg · -24.7% / +25.3%

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: -24.7% / +25.3% around the published quantity. The bounds themselves ship with the dataset on Circa.
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 hazardous waste, underground deposit
Uncertainty: ±25% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Silicon cake (from DBGW filtration) Solid wasteg · -90.6% / +300%

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 inert waste, sanitary landfill
Uncertainty: -90.6% / +300% 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

Dicing slurry (Si/EMC/Cu particles) Solid wasteg

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 hazardous waste, underground deposit
Uncertainty: No range defined.
Unit: g

Emissions to air

3 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 (VOC) Emission to airg

Source citations: web.mit.edu (date not recorded). HD MicroSystems Product Selection Guide, revised December 2013 (MIT-hosted copy). Vendor datasheet.
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

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

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

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

Si Emission to waterg

Derivation basis: No retrievable public document identified

No source is attached to this row.
Source citations: Not stated
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

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

Flows not quantified

3 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)

Adhesive solvent Process chemicalg · -50.2% / +99.7%

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: cut off
Background dataset: Not applicable: this flow is not quantified in the inventory.
Reason: A generic adhesive solvent, typically isopropanol or similar, consumed in small amounts. Isopropanol is already tracked in the main processes, so no separate upstream production dataset is attached here.
Uncertainty: -50.2% / +99.7% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Not quantified - no background dataset available (2)

Cu seed etchant (persulfate or H₂O₂/H₂SO₄) Process chemicalg · -33.3% / +66.7%

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: The etchant that removes the copper seed layer after pattern plating. It is bought as a formulation - either a persulfate bath or a peroxide-and-sulfuric-acid mix - and which one a line uses is process-dependent, so no single background dataset represents it, although each constituent chemistry is available separately. The quantity is recorded here as the formulation and its upstream production is left unlinked.
Uncertainty: -33.3% / +66.7% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Ti seed etchant (dilute HF) Process chemicalg · -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: no background dataset
Background dataset: Not applicable: this flow is not quantified in the inventory.
Reason: The dilute hydrofluoric-acid etchant that removes the titanium seed and barrier layer after copper plating. Hydrofluoric acid itself is mapped in this inventory, but the dilute working formulation sold as an etchant has no equivalent in the background database used for linkage. The quantity is recorded here as the formulation and its upstream production is left unlinked.
Uncertainty: -33.4% / +66.6% around the published quantity. The bounds themselves ship with the dataset on Circa.
Unit: g

Limitations and unquantified flows (2)

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.

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: Ball attach 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