Throttle Valve Stabilization for First-Wafer Deposition Uniformity
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Solution Overview
Problem
The first wafer effect in semiconductor manufacturing, where the first few wafers of a batch exhibit suboptimal qualities such as non-confirming film thickness, uneven film thickness, and poor material properties when switching between different process recipes, leading to waste and increased operational costs due to dummying processes.
Innovation Solution
Implementing a throttle valve stabilization step that determines the throttle valve position to satisfy a criterion corresponding to the current process recipe before proceeding with the deposition process, ensuring the chamber environment is stabilized before each step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a deposition process is initiated without throttle valve stabilization, then the process can proceed quickly, but the first few wafers exhibit suboptimal qualities such as non-confirming film thickness and uneven film thickness
Solution Approach 1:
The patent applies preliminary action by implementing a throttle valve stabilization step before the deposition process begins. The system determines whether the throttle valve position satisfies a criterion corresponding to the current process recipe, and only proceeds with deposition when the criterion is met. This preliminary stabilization action ensures that the chamber environment is properly conditioned before film deposition, eliminating the first wafer effect and ensuring consistent film thickness across all wafers including the first one.
2Manufacturing precision
If dummying processes are used to handle the first wafer effect, then film thickness uniformity can be ensured for subsequent wafers, but waste generation increases and operational costs increase
Solution Approach 1:
The patent applies self-service by enabling the deposition process itself to produce consistent results from the first wafer without requiring separate dummying processes. The throttle valve stabilization step automatically ensures proper chamber conditions before each deposition, allowing the process to serve itself and eliminate the need for sacrificial dummy wafers. This eliminates waste generation while maintaining film thickness uniformity.
3Loss of time
If the throttle valve position is not stabilized before deposition, then the process cycle time is reduced, but the chamber environment remains unstable causing poor material properties
Solution Approach 1:
The patent applies feedback by implementing a criterion-checking mechanism that continuously monitors the throttle valve position and determines whether it satisfies the required criterion for the current process recipe. The system uses this feedback information to decide when to proceed with the deposition process, ensuring that the chamber environment is stable and material properties will be consistent. This feedback-controlled approach maintains reliability without significantly extending process cycle time.
Data Source
AI summary
Technologies related to throttle valve (TV) endpoint control of a deposition process are described. A deposition process may be initialized. During the deposition process, a throttle valve stabilization step may be performed. This throttle valve stabilization step may include determining a throttle valve position for a throttle valve coupled to an exhaust port of the processing chamber and determining whether the throttle valve position satisfies a throttle valve position criterion. The deposition process may proceed to a next step of the deposition process and depositing a film on a substrate in response to determining that the throttle valve position satisfies the throttle valve position criterion.