Elastic Membrane Substrate Holding for Polishing Release
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Solution Overview
Problem
The wafer release process in semiconductor polishing apparatuses can cause instantaneous drying of the wafer surface, leading to defects due to the injection of gases like nitrogen gas between the membrane and the wafer.
Innovation Solution
The apparatus employs a substrate holding member with a pressure chamber and release nozzles, where the pressure chamber is pressurized to create a higher pressure at the center, and a pressurized fluid is injected between the membrane and the substrate to control the release, minimizing surface drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas is injected between the membrane and the wafer to release the wafer, then the wafer release process is achieved, but the wafer surface is instantaneously dried causing defects
Solution Approach 1:
The patent applies preliminary action by pressurizing the entire elastic membrane before injecting gas at the center location. This sequence ensures the membrane is fully swollen and ready for release before the drying-causing gas injection begins, allowing controlled release while minimizing surface drying defects
Solution Approach 2:
The patent applies local quality by injecting gas specifically at the center location of the membrane-wafer contact area rather than uniformly across the entire surface. This localized injection approach enables selective release from the center outward, reducing instantaneous drying of the entire wafer surface while maintaining effective release
2Reliability
If pressure is applied to the membrane to hold the wafer, then the wafer is securely held, but the release process requires additional complexity
Solution Approach 1:
The patent applies segmentation by dividing the pressure chamber into multiple independently controllable regions (center region and peripheral regions). This allows separate control of holding pressure and release gas injection, simplifying the release process while maintaining secure wafer holding through coordinated pressure management in different zones
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 method effectively suppresses wafer surface drying during release, reducing the occurrence of defects and improving the reliability of the polishing process.
Implementation Method 1
a pressure chamber, which are made of an elastic membrane, wherein the pressure chamber has a plurality of areas arranged concentrically and a substrate is pressed against the polishing pad by a pressure in the pressure chamber
Implementation Method 2
one or a plurality of release nozzles configured to inject a pressurized fluid
Implementation Method 3
a substrate holding member having a substrate holding surface and a pressure chamber, which are made of an elastic membrane
Data Source
AI summary
One object is to suppress a substrate from being dried in the course of releasing the substrate from a substrate holding member in an apparatus for polishing. There is provided the apparatus for polishing, comprising: a polishing table configured to support a polishing pad; a substrate holding member having a substrate holding surface and a pressure chamber, which are made of an elastic membrane, wherein the pressure chamber has a plurality of areas arranged concentrically and a substrate is pressed against the polishing pad by a pressure in the pressure chamber; a pressure regulator configured to regulate a pressure of a gas that is supplied to the pressure chamber of the substrate holding member; one or a plurality of release nozzles configured to inject a pressurized fluid; and a control device configured to perform a substrate release process of releasing the substrate from the elastic membrane, the substrate release process controlling the pressure regulator to pressurize entirety of the elastic membrane by pressurizing all the areas in the pressure chamber and subsequently pressurize a center portion of the elastic membrane by pressurizing the pressure chamber such as to make a pressure in one or multiple areas on a center side, which include an area at a center of the pressure chamber, higher than pressures in other areas, wherein meanwhile the substrate release process controls the one or plurality of release nozzles to inject the pressurized fluid to a contact location between the elastic membrane and the substrate.