Elastic Film Top Ring for Uniform Substrate Pressing
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Solution Overview
Problem
Existing top rings for substrate processing apparatuses face challenges in uniformly pressing substrates against polishing pads due to manufacturing tolerances, leading to tilted surfaces and non-parallel contact, which hinders effective polishing.
Innovation Solution
A top ring design incorporating a base member coupled to a rotary shaft, an elastic film forming a pressurization chamber, and a substrate suction member with a porous member and shielding member, allowing for vacuum suction and pressure adjustment to ensure parallel contact and uniform pressing despite tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the suction plate is fitted in the opening of the flange, then the structure is simple and compact, but the substrate cannot be uniformly pressed against the polishing pad when tilted
Solution Approach 1:
The patent introduces an elastic film between the suction plate and the polishing pad. This elastic film acts as a flexible element that can deform to compensate for tilting, allowing the suction plate to remain firmly attached to the polishing pad while maintaining uniform contact pressure across the substrate surface even when the top ring is tilted.
Solution Approach 2:
The patent changes the physical state of the connection between suction plate and polishing pad from rigid to elastic. By introducing the elastic film, the system transitions from a fixed geometric relationship to one that allows dynamic adjustment through elastic deformation, enabling compensation for manufacturing tolerances and tilting.
2Manufacturing precision
If the suction plate is connected via an elastic film to compensate for tilting, then uniform pressing is achieved, but the plane size increases due to space limitations for vacuum passages
Solution Approach 1:
The patent routes the vacuum passages through the thickness dimension of the top ring rather than through the planar area. By utilizing the vertical space and routing passages through the body of the top ring, the design eliminates the need for enlarged planar dimensions while still providing adequate space for vacuum passage routing.
3Manufacturing precision
If manufacturing tolerance is minimized to achieve parallel contact, then uniform pressing is achieved, but the cost and complexity increase
Solution Approach 1:
The elastic film serves a dual function: it maintains the suction connection while automatically compensating for tilting and non-parallelism. The system uses its own elastic deformation capability to correct manufacturing imperfections, eliminating the need for high-precision manufacturing or additional adjustment mechanisms.
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
The design ensures uniform pressing of substrates against polishing pads, preventing slipping and damage, while maintaining a compact size by routing vacuum passages efficiently, thus enhancing polishing efficiency and preventing substrate loss.
Implementation Method 1
This top ring is configured to suction the substrate via micropores of the suction plate by vacuum suction
Implementation Method 2
the suction plate can be aligned with the polishing surface of the polishing pad by the elasticity of the elastic film
Data Source
AI summary
Provided is a top ring that ensures uniformly pressing a substrate against a polishing pad. A top ring 302 for holding a substrate WF includes a base member 301 coupled to a top ring shaft 18, an elastic film 320 that is mounted to the base member 301 and forms a pressurization chamber 322 for pressurizing the substrate WF between the base member 301 and the elastic film 320, a substrate suction member 330 that includes a porous member 334 including a substrate suction surface 334a for suctioning the substrate WF and a pressure reducing portion 334b communicating with a pressure reducing unit 31. The substrate suction member 330 is held to the elastic film 320.