Load-Lock Particle Shielding for Cleaner Wafer Transfer

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Solution Overview

Problem

The transfer of wafer substrates between high and low pressure environments in load-lock chambers used for EUV photolithography is prone to particle contamination due to wear at the gate valve seal and seat, leading to reduced wafer yield and increased maintenance requirements.

Innovation Solution

Incorporating one or more movable shields within the load-lock chamber to protect wafer substrates from particles generated during the closing of gate valves, thereby reducing contamination and maintaining high wafer quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If gate valves are used to transfer wafers between pressure environments, then wafer transfer is enabled, but particle contamination occurs due to seal and seat wear

Engineering Contradiction:

Improvepressure environment transfer capabilityVSAvoidparticle contamination

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

A shield is introduced as an intermediary component between the gate valve and the wafer. The shield intercepts particles generated by gate valve seal and seat wear before they can contaminate the wafer surface, enabling continuous operation without compromising wafer quality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful function of particle generation at the gate valve is separated from the wafer transfer process by positioning the shield to intercept particles at their source, extracting the contamination problem from the critical wafer processing zone

Inventive Principle:

Principle #2Taking out (Extraction)

2Duration of action of stationary object

If gate valve seal and seat wear is allowed to occur, then maintenance intervals are extended, but particle contamination increases

Engineering Contradiction:

Improvegate valve service lifeVSAvoidparticle contamination

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The shield is positioned in advance to intercept particles before they reach the wafer. This protective measure allows the gate valve to operate through normal wear cycles without compromising wafer quality, effectively cushioning against the harmful effects of seal and seat degradation

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If shields are added to protect wafers from particles, then wafer yield increases, but device complexity increases

Engineering Contradiction:

Improvewafer qualityVSAvoidload-lock chamber structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The shield is implemented as a thin, simple barrier component that provides effective particle protection without adding significant structural complexity. The shield can be made from conventional materials and integrated into the existing load-lock chamber design with minimal modification

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS20250164899A1Apparatuses and methods for reducing particle contamination of wafers during transfer

Publication Date: 2025.05.22 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A load-lock chamber with reduced particle contamination is disclosed. At least one movable particle shield is placed between the gate valve and a wafer location. Particles which can be generated due to contact between the gate valve door and its seat are blocked or inhibited by the particle shield from landing in the wafer location, reducing particle contamination. Methods for operating the load-lock chamber are also disclosed.