Polishing Head Pressure Control for Wafer Film Thickness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional substrate polishing devices require extensive time and multiple wafers to accurately obtain the response characteristic under varying polishing conditions, and measurement errors occur due to wafer movement during polishing, making it difficult to achieve uniform polishing forces and precise film thickness control.
Innovation Solution
A substrate processing apparatus with a polishing head, pressure control unit, film thickness measurement unit, and response characteristic acquisition unit that individually controls pressure chambers, measures film thickness distribution, and acquires the response characteristic by changing preset pressures during polishing, allowing for real-time measurement and standardization of polishing rates to reduce temporal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple wafers are polished under different pressure conditions to acquire response characteristic data, then the accuracy of the response characteristic is improved, but the time required and wafer consumption increase significantly
Solution Approach 1:
The patent applies preliminary action by measuring the film thickness distribution at the start of polishing (before polishing occurs) and using this initial measurement as the basis for calculating the polishing rate. This eliminates the need to wait for the polishing process to complete and measure the final film thickness, thereby significantly reducing the time required to acquire response characteristic data while maintaining measurement accuracy.
2Measurement precision
If film thickness is measured after polishing to determine polishing rate, then the measurement can be performed with standard equipment, but measurement errors occur due to wafer movement during polishing
Solution Approach 1:
The patent measures the film thickness distribution at the beginning of the polishing process (before the wafer is subjected to polishing forces that cause movement). By capturing the film thickness in this stable, pre-polishing state, the system eliminates measurement errors caused by wafer movement during polishing while still being able to calculate the polishing rate through comparison with post-polishing measurements.
3Adaptability or versatility
If multiple pressure conditions are tested with multiple wafers to obtain comprehensive response characteristic data, then the completeness of the response characteristic is improved, but the device complexity and operational complexity increase
Solution Approach 1:
The patent implements feedback by using the measured film thickness distribution and calculated polishing rate to determine the appropriate pressure conditions for subsequent polishing operations. The system automatically adjusts pressure chamber settings based on the measured response characteristics, eliminating the need for manual testing of multiple pressure conditions with multiple wafers. This reduces operational complexity while maintaining comprehensive response characteristic data through automated feedback-based optimization.
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
Enables accurate and simplified acquisition of the response characteristic in a single polishing cycle, reducing the influence of temporal changes and measurement errors, thus improving the efficiency and accuracy of substrate polishing.
Implementation Method 1
The pressure control unit is configured to perform pressure feedback control by individually controlling pressures in the pressure chambers
Implementation Method 2
The film thickness measurement unit is configured to measure a film thickness distribution of the substrate that is being polished
Implementation Method 3
the surface of the wafer is brought into sliding contact with the polishing surface in the presence of polishing liquid
Implementation Method 4
the surface of the wafer is pressed against the polishing surface of the polishing pad... the surface of the wafer is polished
Data Source
AI summary
A substrate processing apparatus includes a polishing head defining plural pressure chambers D1 to D5 for pressing a wafer W on a polishing pad 42, a pressure control unit performing pressure feedback control by individually controlling pressures in the pressure chambers D1 to D5, a film thickness measurement unit measuring a film thickness distribution of the wafer W being polished, a storage unit storing multiple pieces of information on a preset pressure of the pressure chambers D1 to D5, and a response characteristic acquisition unit changing the preset pressure every time a predetermined condition is satisfied during polishing of the wafer W, measuring a polishing rate applied to the wafer W, and acquiring a response characteristic of the polishing of the wafer W. The response characteristic indicates responsiveness of the polishing of the wafer W to the pressure feedback. The response characteristic is acquired based on the obtained polishing rates.