Load-Lock Gas Diffuser Layout for Faster Wafer Pressurization
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Solution Overview
Problem
Existing load-lock chamber designs face challenges in reducing flow-induced particle contamination during the pressurization process in semiconductor wafer inspection, which can lead to defects and decreased yield, while also compromising system throughput due to slow pressurization operations.
Innovation Solution
A low-volume load-lock chamber design with a ceiling-mounted gas vent and a plate positioned between the gas vent and the wafer, optimized to divert gas flow perpendicular to the wafer, reducing flow-induced contamination and accelerating the pressurization process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas is vented into the load-lock chamber during pressurization, then the chamber pressure increases and throughput improves, but particle contamination occurs on the wafer surface
Solution Approach 1:
A gas diffuser is introduced as an intermediary component between the gas vent and the wafer. The diffuser disperses the gas flow into multiple smaller streams, reducing the direct impact velocity and preventing particles from being deposited onto the wafer surface during pressurization, thereby resolving the contradiction between fast pressurization and contamination prevention
Solution Approach 2:
The gas flow parameters are changed by using a diffuser structure that transforms a single high-velocity gas jet into multiple lower-velocity streams. This parameter change reduces the kinetic energy of the gas flow, preventing particle contamination while maintaining the overall pressurization rate needed for high throughput
2Loss of time
If the load-lock chamber volume is reduced to accelerate pressurization, then pressurization time decreases and throughput increases, but the chamber may not accommodate standard wafer sizes
Solution Approach 1:
The load-lock chamber is designed with non-uniform volume distribution - the region above the wafer is minimized to reduce pressurization time, while the overall chamber volume is sufficient to accommodate standard wafer sizes. This local optimization allows fast pressurization without compromising wafer accommodation
Solution Approach 2:
The gas venting strategy is optimized by directing gas flow in specific patterns and using a diffuser to distribute flow in multiple directions. This dimensional approach to gas flow management allows efficient pressurization of a compact chamber volume while maintaining compatibility with standard wafer dimensions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively minimizes particle contamination and reduces pressurization time from 30 seconds to 15 seconds, maintaining high throughput and reducing the risk of defects, thereby improving the yield and robustness of the charged-particle inspection apparatus.
Implementation Method 1
a gas vent arranged at a ceiling of the chamber and configured to vent gas into the chamber with a flow rate of at least twenty normal liters per minute
Implementation Method 2
a plate fixed to the ceiling between the gas vent and the wafer
Data Source
AI summary
A load-lock system may include a chamber enclosing a supporting structure configured to support a wafer; a gas vent arranged at a ceiling of the chamber and configured to vent gas into the chamber with a flow rate of at least twenty normal liters per minute; and a plate fixed to the ceiling between the gas vent and the wafer.