Wafer Support Protrusions for Particle Reduction
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Solution Overview
Problem
Conventional wafer-supporting devices in semiconductor-processing chambers face issues with particle accumulation and film uniformity due to contact between the wafer's reverse side and the susceptor, with existing emboss and dimple types not fully addressing these problems.
Innovation Solution
A wafer-supporting device with protrusions having rounded tips is designed, where the number and height of protrusions are optimized to minimize contact area, using the inequities (−0.5N+40)≤H≤53 and 5≤N≤100, to ensure point contact and reduce particle accumulation while maintaining film quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If protrusions are provided on the wafer-supporting device to reduce contact area, then particle accumulation is reduced, but wafer sagging occurs between contact points
Solution Approach 1:
The invention applies local quality by creating specific protrusions with rounded tips at determined positions on the wafer-supporting device. These protrusions provide localized contact points that reduce overall contact area while maintaining adequate support. The rounded tip geometry concentrates contact to small areas, minimizing particle accumulation zones while the strategic positioning ensures sufficient support to prevent wafer sagging between contact points.
Solution Approach 2:
The invention implements preliminary action by pre-determining the optimal number and positions of protrusions before wafer processing. The protrusions are arranged in advance to provide both particle reduction and sagging prevention functions. This pre-planned configuration ensures that when a wafer is placed on the device, the contact points are already optimally positioned to balance particle accumulation reduction with wafer support stability.
2Object-generated harmful factors
If protrusions with rounded tips are used to reduce contact area, then particle accumulation is reduced, but film stress increases
Solution Approach 1:
The invention applies parameter changes by carefully controlling the geometric parameters of the protrusions, specifically the tip radius and height. The tip radius is optimized to be small enough to reduce contact area and particle accumulation, but not so small that it creates excessive stress concentration. The height of protrusions is also controlled to provide adequate support while limiting stress transmission to the film. These parameter optimizations balance particle reduction with film stress management.
3Object-generated harmful factors
If protrusions are provided to reduce contact area, then particle accumulation is reduced, but film thickness uniformity deteriorates
Solution Approach 1:
The invention applies segmentation by dividing the support function into multiple discrete protrusions rather than using a continuous support surface. This segmentation reduces the contact area to specific points, minimizing particle accumulation zones. The protrusions are strategically positioned to segment the support function while maintaining adequate coverage across the wafer surface, ensuring both particle reduction and film uniformity.
Solution Approach 2:
The invention implements preliminary action by pre-determining the optimal number and positions of protrusions before wafer processing. The protrusions are arranged in advance to provide both particle reduction and sagging prevention functions. This pre-planned configuration ensures that when a wafer is placed on the device, the contact points are already optimally positioned to balance particle accumulation reduction with wafer support stability.
Data Source
AI summary
A wafer-supporting device for supporting a wafer thereon adapted to be installed in a semiconductor-processing apparatus includes: a base surface; and protrusions protruding from the base surface and having rounded tips for supporting a wafer thereon. The rounded tips are such that a reverse side of a wafer is supported entirely by the rounded tips by point contact. The protrusions are disposed substantially uniformly on an area of the base surface over which a wafer is placed, wherein the number (N) and the height (H [μm]) of the protrusions as determined in use satisfy the following inequities per area for a 300-mm wafer:(−0.5N+40)≤H≤53;5≤N≤100.