Wafer Holder Shape Control for Uniform Brush Cleaning
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Solution Overview
Problem
The existing substrate processing apparatuses face inefficiencies in cleaning the wafer surfaces due to curvature caused by weight and applied loads, leading to reduced contact area and frequency of cleaning, especially when the brush is pressed against the center portion from below.
Innovation Solution
A substrate processing apparatus with a substrate holder that controls the center portion's displacement upward or downward during processing, using pressers and grippers to adjust forces and distance, and a displacement sensor to maintain optimal substrate shape, ensuring efficient cleaning by varying the contact surface with the cleaner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the brush is pressed against the back-surface center portion of the wafer from below to clean it, then the cleaning force is improved, but the center portion of the wafer is displaced upwardly and the lower surface becomes curved, reducing the contact area between the brush and wafer
Solution Approach 1:
The patent makes the wafer dynamically deformable by controlling the suction force applied by the spin chuck. By adjusting the suction force, the wafer can be returned to a flat state after being pressed by the brush, enabling repeated cleaning cycles with maintained contact area. This dynamic control resolves the contradiction between applying cleaning force and maintaining contact area.
Solution Approach 2:
The patent changes the physical state of the wafer by controlling the suction force parameter. By varying the suction force, the wafer's curvature is controlled, allowing it to return to a flat state after brush contact. This parameter change enables the system to overcome the displacement issue and maintain effective cleaning contact.
2Ease of operation
If the peripheral portion of the wafer is held by suction pads to enable cleaning, then the wafer can be processed, but the center portion is displaced downwardly due to weight and the lower surface becomes curved, reducing cleaning effectiveness
Solution Approach 1:
The patent dynamically adjusts the suction force during the cleaning process. Initially, suction pads hold the wafer periphery for stable handling, then during cleaning, the suction force is increased to flatten the wafer surface, ensuring maximum contact area between the brush and wafer throughout the cleaning operation.
Solution Approach 2:
The patent applies preliminary action by pre-adjusting the suction force before cleaning begins. The suction force is controlled in advance to maintain the wafer in a flat state during brush contact, preventing curvature development that would reduce cleaning effectiveness.
3Stability of the object's composition
If the wafer is held firmly during cleaning to prevent movement, then positioning stability is improved, but the contact area between the brush and wafer is reduced due to curvature from applied loads
Solution Approach 1:
The patent employs dynamic control of suction force to simultaneously achieve positioning stability and maintain wafer flatness. By adjusting the suction force parameter, the system maintains the wafer in a stable yet flat state, ensuring both positioning stability and maximum brush contact area during cleaning.
Data Source
AI summary
A substrate processing apparatus includes a substrate holder that holds an outer peripheral end of a substrate, a processor that processes a front surface or a back surface of the substrate, and a holding controller that controls the substrate holder such that a center portion of the substrate is displaced in an upward direction or a downward direction in a period during which the substrate is processed by the processor.