Substrate Processing Rollers and Bernoulli Chucks for Flat Wafer Polishing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing substrate processing apparatuses face challenges in achieving uniform polishing rates across the entire surface of a wafer due to bending issues caused by uneven polishing loads, which are exacerbated by the structural limitations of Bernoulli chucks in supporting the polishing process.
Innovation Solution
The apparatus employs a configuration with two rollers positioned adjacent to the pressing member, located radially outward and supporting the pressing force, combined with Bernoulli chucks to support the substrate in a non-contact manner, to reduce bending and ensure uniform polishing across the wafer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the polishing load of the outer pressing member is increased to achieve uniform polishing rate, then the polishing rate uniformity is improved, but the wafer bends upward causing non-uniform polishing
Solution Approach 1:
The patent introduces Bernoulli chucks that generate upward suction force to counterbalance the downward pressing force applied by the outer pressing member. This counterbalancing prevents wafer bending while maintaining the necessary polishing pressure, resolving the contradiction between achieving uniform polishing rate and maintaining wafer flatness.
Solution Approach 2:
The patent changes the physical state by introducing fluid pressure fields through Bernoulli chucks. By controlling the fluid pressure parameters, the system dynamically adjusts the support force to match the polishing load, enabling uniform polishing without wafer deformation.
2Shape
If Bernoulli chucks are positioned closer to the polishing point, then the wafer bending is reduced, but the structural complexity increases due to roller and drive mechanism constraints
Solution Approach 1:
The patent positions Bernoulli chucks in the radial direction at specific distances from the center, utilizing the radial dimension to optimize their location. This dimensional approach allows the chucks to be positioned at an optimal distance that provides sufficient support force while avoiding interference with the roller and drive mechanism in the tangential direction.
3Shape
If the polishing load is reduced to prevent wafer bending, then the wafer flatness is maintained, but the overall polishing rate decreases
Solution Approach 1:
By introducing Bernoulli chucks that generate upward suction force as a counterbalancing force, the system can apply higher downward polishing pressure without causing wafer bending. The counterbalancing effect allows the outer pressing member to maintain high polishing load while the wafer remains flat, thus preserving both productivity and shape integrity.
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 configuration allows for uniform application of pressing force, achieving a target removal rate and uniform polishing across the entire substrate surface while minimizing upward bending.
Implementation Method 1
Bernoulli chucks 508 are disposed on the back surface of the wafer W, as shown in FIGS. 15 and 16. Each Bernoulli chuck 508 is configured to generate suction force by discharging fluid and to attract the back surface of the wafer W downward.
Data Source
AI summary
The present invention relates to a substrate processing apparatus for processing a substrate, such as a wafer, and more particularly to a substrate processing apparatus for processing a surface of a substrate by pressing a processing tool against the surface of the substrate while holding a circumferential portion of the substrate with rotating rollers. The substrate processing apparatus includes a plurality of rollers (11A to 11D) arranged around a reference central point (CP) and configured to contact the circumferential portion of the substrate W, a processing tool (3) configured to press a pressing member (21A) against a periphery of the substrate W, and an actuator (22A) configured to apply a pressing force to the pressing member (21A). Two (11A, 11B) of the plurality of rollers (11A to 11D) are arranged adjacent to the pressing member (21A) and located at both sides of the pressing member (21A).