Substrate Polishing Control for Uniform Radial Cleaning
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Solution Overview
Problem
Existing substrate processing apparatuses face challenges in uniformly polishing substrates across their radial direction without causing scratches, as the scanning speed and rotation speed of the polishing brush decrease from the center to the edge, leading to inadequate cleaning and polishing in peripheral areas.
Innovation Solution
A substrate processing apparatus with a controller that divides the substrate into radial areas, controls the supply of cleaning liquid, and manages the scanning of a polishing head in a way that stops liquid supply during scanning, preventing excessive friction and ensuring a consistent polishing pressure, speed, and rotation speed across different areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the polishing brush scans from the center to the edge of the substrate while rotating, then the center area can be polished, but the scanning speed and rotation speed decrease in peripheral areas leading to inadequate polishing
Solution Approach 1:
The substrate surface is divided into multiple radial areas (first, second, third areas) with different polishing conditions. Each area receives customized polishing parameters including rotation speed, scanning speed, and cleaning liquid supply, allowing the center and peripheral areas to be polished independently with optimal parameters for each region.
Solution Approach 2:
Different polishing conditions are applied to different radial positions on the substrate. The center area uses one set of parameters while peripheral areas use different parameters to compensate for the natural decrease in linear velocity, ensuring uniform polishing quality across the entire substrate surface.
2Object-generated harmful factors
If cleaning liquid is continuously supplied during polishing, then debris can be removed, but excessive friction occurs leading to substrate cutting
Solution Approach 1:
The cleaning liquid supply is controlled in periodic cycles: supplied during polishing to remove debris, then stopped during a pause period to reduce friction. This periodic supply and interruption prevents continuous friction that would cause cutting while still effectively removing polishing debris through the liquid film.
Solution Approach 2:
The cleaning liquid acts as an intermediary substance that mediates between the polishing brush and substrate. It provides lubrication to reduce friction and prevent cutting, while also carrying away polishing debris. The controlled interruption of this intermediary allows friction to be reduced when debris removal is less critical.
3Productivity
If the polishing head scans at high speed, then productivity increases, but the liquid film becomes too thin causing scratches on the substrate
Solution Approach 1:
The system alternates between polishing periods with high scanning speed for productivity and pause periods where the polishing head retracts or stops. During pause periods, cleaning liquid is supplied to maintain an adequate liquid film thickness, preventing scratches while allowing high-speed polishing to occur during the active periods.
Solution Approach 2:
Before high-speed polishing begins, cleaning liquid is supplied in advance to establish an adequate liquid film on the substrate surface. This preliminary lubrication prevents scratches that would occur during subsequent high-speed scanning, allowing productivity to increase without compromising surface quality.
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
This approach allows for uniform polishing across the substrate's radial direction, reducing scratches and ensuring effective cleaning and polishing, while maintaining the appropriate thickness of the liquid film to prevent cutting and remove debris efficiently.
Implementation Method 1
a liquid supply part configured to supply a cleaning liquid to a main surface of the substrate
Implementation Method 2
a polishing head configured to polish the main surface of the substrate; a moving part configured to scan the polishing head in a radial direction of the substrate while pressing the polishing head against the main surface of the substrate
Implementation Method 3
a rotating part configured to rotate the holding part to rotate the substrate together with the holding part
Data Source
AI summary
A substrate processing apparatus includes: a holding part for holding a substrate; a rotating part for rotating the holding part to rotate the substrate together with the holding part; a liquid supply part for supplying a cleaning liquid to a main surface of the substrate; a polishing head for polishing the main surface; a moving part for scanning the polishing head in a radial direction of the substrate while pressing the polishing head against the main surface; and a controller for controlling the rotating part, the liquid supply part, and the moving part. The controller sets a division line that divides the main surface into plural areas in the radial direction, and controls the liquid supply part to supply the cleaning liquid for each area and controls the moving part to scan the polishing head for each area while a subsequent supply of the cleaning liquid is stopped.