Wafer Positioning via Backside Z Height Double Derivative Detection
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Solution Overview
Problem
Conventional wafer positioning methods in semiconductor manufacturing are inefficient and inaccurate, particularly under high temperature conditions, as they require chamber temperature reduction for visibility and fail to maintain precise positioning due to temperature-induced changes in gas flow and temperature fields.
Innovation Solution
A method involving the detection of the backside Z height double derivative (BZDD) distribution of a wafer surface after thin film processing to determine its positioning accuracy and adjust the positioning of subsequent wafers to achieve ideal center alignment during the thin film process, using a semiconductor manufacturing apparatus with a processor and executable program instructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the chamber light is turned on to enable visual observation for wafer positioning, then the positioning can be conducted, but the chamber must be turned off and temperature decreased, causing manufacturing delays
Solution Approach 1:
The patent replaces the mechanical/optical observation system (requiring chamber light and visual inspection) with a sensor-based detection system. Sensors detect wafer position, thickness distribution, or temperature fields directly under process conditions, eliminating the need to stop production for visual inspection and enabling continuous manufacturing without compromising positioning accuracy.
Solution Approach 2:
The patent changes the detection parameter from visual observation (requiring room temperature and light) to physical field detection (temperature field, thickness distribution, or sensor signals) that can be measured under high temperature process conditions. This allows positioning to be performed without changing chamber temperature or stopping the manufacturing process.
2Ease of operation
If wafer positioning is performed under room temperature conditions, then visual observation is possible, but the positioning accuracy deteriorates under high temperature process conditions due to changes in gas flow and temperature fields
Solution Approach 1:
The patent replaces room temperature visual observation with in-situ sensor detection that operates under high temperature process conditions. The sensors measure physical parameters (position, thickness, temperature) directly during the epitaxial process, providing accurate positioning data that reflects actual process conditions without requiring temperature changes or visual inspection.
Solution Approach 2:
The patent implements a feedback mechanism where sensors continuously detect wafer position or thickness distribution under process temperature, and this information is used to adjust or confirm positioning in real-time. This closed-loop approach ensures positioning accuracy under actual high temperature conditions rather than relying on room temperature predictions.
Data Source
AI summary
The invention provides a method for positioning a wafer and a semiconductor manufacturing apparatus, which are applied to thin film processes. The method includes: Step S1: Obtain the state distribution of the first surface of the first wafer after the thin film process is performed on the first wafer, wherein the first surface is the surface opposite to a surface that the thin film formed thereon in the thin film process; Step S2: Determine whether the first wafer is located at the ideal positioning center according to the state distribution of the first surface, when the first wafer is not located at the ideal positioning center, according to the state distribution of the first surface adjusts the positioning position of the second wafer to be subjected to the thin film process, so that the second wafer is positioned at the ideal positioning center during the thin film process. According to the present invention, the wafer is positioned at the ideal positioning center during the thin film process, thereby improving the quality of the thin film layer and the entire wafer (epitaxial wafer) after the thin film process, and improving the effect of the thin film process.