PECVD Chamber Gap Calibration for Wafer Thickness Consistency
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Solution Overview
Problem
Existing plasma-enhanced chemical vapor deposition (PECVD) equipment fails to maintain consistent wafer-to-showerhead spacing due to surface deposits, leading to inconsistent film thickness across wafers in different batches or process locations.
Innovation Solution
A process chamber with integrated distance measuring modules and drive sources to adjust the carrying platform's position, ensuring real-time gap calibration and maintaining consistent film thickness by measuring and correcting the gap between the wafer and showerhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional inter-wafer gap measurement system is used for calibration, then initial gap accuracy can be achieved, but gap consistency cannot be maintained during processing due to surface deposits
Solution Approach 1:
The patent applies preliminary action by performing gap calibration before processing begins. The distance measuring module measures the gap between the wafer and showerhead, and the drive source adjusts the carrying platform position to achieve the target gap value before deposition starts. This preliminary calibration ensures accurate initial gap setting, though the patent acknowledges that re-calibration may be needed during processing due to surface deposits accumulating on the carrying plate or showerhead.
2Device complexity
If carrying platform position is fixed after assembly calibration, then device complexity is reduced, but film thickness consistency deteriorates due to gap fluctuations
Solution Approach 1:
The patent implements feedback by using the distance measuring module to continuously monitor the gap between the wafer and showerhead during processing. When the measured gap deviates from the target value, the control system activates the drive source to adjust the carrying platform position, creating a closed-loop feedback control system. This feedback mechanism maintains film thickness consistency by compensating for gap fluctuations caused by surface deposits, though it increases device complexity compared to fixed position systems.
3Measurement precision
If multiple manual measurements are performed to ensure gap accuracy, then measurement precision improves, but productivity decreases due to repeated chamber openings
Solution Approach 1:
The patent applies continuity of useful action by implementing continuous gap monitoring during processing using the distance measuring module. Instead of requiring repeated chamber openings for manual measurements, the system continuously measures the gap between wafer and showerhead and automatically adjusts the carrying platform position to maintain the target gap value throughout the deposition process. This continuous automated monitoring eliminates production interruptions while maintaining measurement precision.
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
Ensures consistent film thickness across wafers by providing real-time gap calibration, eliminating the need for repeated chamber measurements and improving production efficiency.
Implementation Method 1
at least one first distance measuring module disposed on the spray assembly for measuring a first distance between the module and the wafer on the carrying platform
Data Source
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AI summary
The present disclosure provides a calibration method for a process chamber, semiconductor processing device, and a carrying platform. The process chamber includes a chamber body and at least one process station disposed within the chamber body. Each process station includes a carrying platform movably connected to the chamber body and a spray assembly disposed directly above the carrying platform. The process chamber also includes: at least one first distance measuring module disposed on the spray assembly, which is used to measure a first distance between itself and a wafer on the carrying platform; and a first drive source connected to the carrying platform, which is used to drive the carrying platform to move up and down according to the first distance. The present disclosure can calibrate the gap value in real time to ensure film thickness consistency between wafers in different batches or at different workstations.