How to Clean Metal Off Wafers After EUV Chipmaking
This patent describes a specialized system and cleaning fluid used to precisely remove tiny metal bits from silicon wafers after they've been patterned using extreme ultraviolet light for making advanced computer chips.
Original patent title: “Metal-compound-removing solvent and method in lithography”
This patent describes a specialized system and cleaning fluid used to precisely remove tiny metal bits from silicon wafers after they've been patterned using extreme ultraviolet light for making advanced computer chips. Owned by Taiwan Semiconductor Manufacturing Co TSMC with 23 claims, and it is expected to expire in 2045.
Coverage
What does this patent actually cover?
This patent describes a system and method for cleaning semiconductor wafers after they've been processed using Extreme Ultraviolet (EUV) lithography. The system includes a chamber to coat a wafer with a "metal-containing photoresist material" (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1). After patterning, "first nozzles" apply a "cleaning fluid" specifically designed to remove "metal contaminants" that come from this photoresist (Claim 1). The cleaning fluid contains a solvent with specific "Hansen solubility parameters" (delta D between 13-25, delta P between 3-25, delta H between 4-30) and an acid or base with a defined "acid dissociation constant" (Claim 2). "Second nozzles" then apply a "purging fluid" to further help remove these contaminants (Claim 1). The system can also spin the wafer (Claim 3) and spray fluids onto its backside or edges (ClaimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more → 6-9). For example, after an EUV exposure step, a wafer might have trace amounts of tin (Sn) from the photoresist, which this system's specialized cleaning fluid and process would remove to ensure the chip's quality.
The gap
What does this patent NOT cover?
- Cleaning processes that do not use a metal-containing photoresist material in the EUV lithography step.
- Cleaning fluids that do not meet the specified Hansen solubility parameters (delta D, P, H ranges).
- Cleaning fluids that do not contain an acid with a pKa between -11 and 4, or a base with a pKa between 9 and 40.
- Systems that do not include both distinct cleaning fluid nozzles and distinct purging fluid nozzles.
- The use of non-EUV lithography processes for patterning the photoresist.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The noveltynoveltyThe requirement that an invention be different from anything publicly known before its priority date.Read more → lies in precisely defining the chemical properties of the cleaning solvent using "Hansen solubility parameters" (delta D, P, H) in combination with a specific acid or base strength (acid dissociation constant). This allows for highly selective and efficient removal of specific metal contaminants, which is crucial for the extremely demanding purity requirements of EUV lithography.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Advanced semiconductor fabrication plants
EUV lithography process lines
Manufacturing of leading-edge CPUs
Production of high-density memory chips
Why it matters
The bigger picture
As computer chips get smaller, the features printed on them become incredibly tiny, requiring advanced techniques like Extreme Ultraviolet (EUV) lithography. This process often uses photoresists that contain metals, which can leave behind minute metal contaminants. These contaminants can ruin the delicate chip structures, leading to defects. This patent addresses a critical step in manufacturing advanced semiconductors, ensuring the purity and performance of next-generation microprocessors and memory chips.
Filed
January 17, 2025
Market context
Who's building on this
Companies in this space
Taiwan Semiconductor Manufacturing Co (TSMC), the assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, is a global leader in semiconductor manufacturing and is heavily invested in EUV technology. Other major foundries and integrated device manufacturers (IDMs) like Samsung Foundry and Intel also operate advanced fabs that would utilize similar sophisticated cleaning processes. Equipment suppliers like ASML (for EUV scanners) and various chemical suppliers also contribute to this ecosystem.
Market impact
This patent addresses a critical bottleneck in the production of advanced semiconductors using EUV lithography. By providing a specific solution for removing metal contaminants, it helps improve manufacturing yields and enables the continued scaling of chip features. This directly impacts the ability to produce faster, more powerful, and more energy-efficient processors for everything from smartphones to data centers, maintaining the rapid pace of innovation in the electronics industry.
Claim 1 — Plain English
What this patent covers
This patent describes a system and method for cleaning semiconductor wafers after they've been processed using Extreme Ultraviolet (EUV) lithography. The system includes a chamber to coat a wafer with a "metal-containing photoresist material" (Claim 1). After patterning, "first nozzles" apply a "cleaning fluid" specifically designed to remove "metal contaminants" that come from this photoresist (Claim 1). The cleaning fluid contains a solvent with specific "Hansen solubility parameters" (delta D between 13-25, delta P between 3-25, delta H between 4-30) and an acid or base with a defined "acid dissociation constant" (Claim 2). "Second nozzles" then apply a "purging fluid" to further help remove these contaminants (Claim 1). The system can also spin the wafer (Claim 3) and spray fluids onto its backside or edges (Claims 6-9). For example, after an EUV exposure step, a wafer might have trace amounts of tin (Sn) from the photoresist, which this system's specialized cleaning fluid and process would remove to ensure the chip's quality.
The clever bit
The novelty lies in precisely defining the chemical properties of the cleaning solvent using "Hansen solubility parameters" (delta D, P, H) in combination with a specific acid or base strength (acid dissociation constant). This allows for highly selective and efficient removal of specific metal contaminants, which is crucial for the extremely demanding purity requirements of EUV lithography.
What it does not cover
- Cleaning processes that do not use a metal-containing photoresist material in the EUV lithography step.
- Cleaning fluids that do not meet the specified Hansen solubility parameters (delta D, P, H ranges).
- Cleaning fluids that do not contain an acid with a pKa between -11 and 4, or a base with a pKa between 9 and 40.
- Systems that do not include both distinct cleaning fluid nozzles and distinct purging fluid nozzles.
- The use of non-EUV lithography processes for patterning the photoresist.
Patent timeline
Application submitted to the patent office
Patent enters public domain
PatentBrief Score
Impact Score
Limited data
Citation count
0/40
No citations yet
Claim breadth
15/20
Broad claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$29K – $94K
Midpoint $59K · 18.5 yr remaining · industry ×1.5
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
The original legal language
Original claims
23 claims as filed with the patent office.
Concepts involved
Cite this patent
Cheng, J., Chang, C., & Zi, A. How to Clean Metal Off Wafers After EUV Chipmaking (U.S. Patent No. 20,250,172,879). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/20250172879/metal-compound-removing-solvent-and-method-in-lithography
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How to Clean Metal Off Wafers After EUV Chipmaking cover?
This patent describes a specialized system and cleaning fluid used to precisely remove tiny metal bits from silicon wafers after they've been patterned using extreme ultraviolet light for making advanced computer chips.
Who owns patent US 20250172879?
This patent is owned by Taiwan Semiconductor Manufacturing Co TSMC.
When does this patent expire?
This patent is expected to expire on January 17, 2045, when the invention enters the public domain.
What problem does this patent solve?
As computer chips get smaller, the features printed on them become incredibly tiny, requiring advanced techniques like Extreme Ultraviolet (EUV) lithography. This process often uses photoresists that contain metals, which can leave behind minute metal contaminants. These contaminants can ruin the delicate chip structures, leading to defects. This patent addresses a critical step in manufacturing advanced semiconductors, ensuring the purity and performance of next-generation microprocessors and memory chips.
What does this patent NOT cover?
Cleaning processes that do not use a metal-containing photoresist material in the EUV lithography step.
Same assignee
More from Taiwan Semiconductor Manufacturing Co TSMC
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