Wafer Support Plate Structure for Low Thermal Mass and Clean Handling
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Solution Overview
Problem
Existing semiconductor wafer supports for high-temperature heat treatment in vertical furnaces often cause contamination and slip due to contact with hole edges and inadequate stress relief, leading to production issues like photolithography overlay failures and yield losses.
Innovation Solution
A wafer support system featuring a plate with a smooth, hole-free support surface and a recessed surface with slots that reduce thermal mass and stress, preventing contamination and slip by distributing thermal gradients evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If holes are provided in the support plate to reduce thermal mass, then thermal mass is reduced, but wafer contamination occurs due to contact with hole edges
Solution Approach 1:
The plate is segmented into multiple regions: a support surface region that contacts the wafer and is free of holes, and a recessed surface region that contains holes for stress relief. This segmentation allows the plate to simultaneously reduce thermal mass through holes while preventing contamination by keeping the support surface hole-free.
Solution Approach 2:
Different regions of the plate have different properties: the support surface is solid and hole-free to prevent contamination, while the recessed surface contains holes to reduce thermal mass and relieve stress. This local differentiation of properties resolves the contradiction between reducing thermal mass and preventing contamination.
2Stress or pressure
If holes are provided in the support plate to relieve stress, then stress relief is improved, but wafer slip occurs due to inadequate support
Solution Approach 1:
The plate is divided into a support surface region without holes for stable wafer support and a recessed surface region with holes for stress relief. This segmentation allows simultaneous achievement of wafer stability and stress relief.
Solution Approach 2:
The holes are positioned in a recessed surface that is vertically spaced from the support surface, creating a three-dimensional structure. This dimensional separation allows the holes to relieve stress without compromising the two-dimensional support stability at the wafer contact level.
3Object-affected harmful factors
If the support surface is made solid to prevent contamination, then contamination is prevented, but thermal mass increases leading to excessive thermal stress
Solution Approach 1:
The plate structure is segmented into a solid support surface for contamination prevention and a recessed surface with holes for stress relief, allowing both objectives to be achieved simultaneously.
Solution Approach 2:
The support surface is locally optimized to be solid and hole-free for contamination prevention, while the recessed surface is locally optimized to contain holes for stress relief, resolving the contradiction between contamination prevention and stress management.
4Strength
If the plate thickness is increased to improve mechanical stability, then mechanical stability is improved, but thermal mass increases causing excessive thermal stress
Solution Approach 1:
The plate is designed as a thin structure with a recessed surface containing holes, reducing overall thermal mass while maintaining mechanical stability through optimized geometry and support structure rather than increased thickness.
Solution Approach 2:
The plate incorporates a porous structure with holes in the recessed surface, reducing thermal mass and thermal stress while maintaining adequate mechanical stability for wafer support.
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 solution effectively prevents contamination and slip during high-temperature processing, enhancing wafer stability and increasing throughput by up to 50% without compromising quality, while maintaining mechanical stability and reducing manufacturing costs.
Implementation Method 1
A plate for supporting the semiconductor wafer includes top and bottom surfaces. The top surface includes a support surface and a recessed surface spaced vertically from the support surface. The plate includes a plurality of holes that extend from the recessed surface to the bottom surface.
Implementation Method 2
The support surface is free of holes to inhibit contamination of the wafer
Implementation Method 3
A plurality of holes extends from the recessed surface, and the support surface is free of holes to inhibit contamination of the wafer
Data Source
AI summary
A support for a semiconductor wafer includes a plate having a support surface for supporting the wafer and a recessed surface spaced from the support surface and spaced from the wafer. A plurality of holes extends from the recessed surface, and the support surface is free of holes to inhibit contamination of the wafer.