Flat Pocket Susceptor Venting for Wafer Temperature Uniformity
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Solution Overview
Problem
Existing semiconductor susceptor designs cause temperature non-uniformity across substrates due to non-uniform heat transfer, leading to reduced quality of deposited layers, particularly near the edges and center of the substrate.
Innovation Solution
A susceptor with a patterned top surface featuring substrate support features separated by venting channels, reducing the contacting surface area and incorporating radial bumps to center the substrate, thereby enhancing thermal uniformity by minimizing conductive heat transfer and promoting radiant heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the susceptor has a large contacting surface area with the substrate, then conductive heat transfer is enhanced, but temperature non-uniformity increases and hot spots form near the edges and center
Solution Approach 1:
The susceptor surface is segmented into discrete support features (legs, posts, or pillars) rather than a continuous flat surface. This segmentation reduces the total contacting surface area while maintaining substrate support, thereby minimizing conductive heat transfer paths that cause hot spots and improving temperature uniformity across the substrate.
Solution Approach 2:
The susceptor design transitions from uniform contact across the entire surface to localized contact only at specific support feature locations. This local quality approach allows different regions of the susceptor to have different functions: the support features provide mechanical support and minimal conductive heating, while the recessed pocket provides radiant heating coverage, resulting in improved overall temperature uniformity.
2Temperature
If the susceptor uses a flat continuous surface, then manufacturing is simple, but temperature non-uniformity occurs across the substrate
Solution Approach 1:
The susceptor is manufactured with segmented support features using techniques such as machining, molding, or additive manufacturing. While this increases fabrication complexity compared to a simple flat surface, it enables precise control over contact locations and areas, ultimately improving temperature uniformity during substrate processing.
Solution Approach 2:
The susceptor design adds vertical dimensionality by creating recessed pockets and elevated support features, transforming a two-dimensional flat surface into a three-dimensional structured surface. This dimensional change allows the susceptor to provide both mechanical support and controlled thermal characteristics, improving temperature uniformity despite increased manufacturing complexity.
3Temperature
If the susceptor has minimal contact points, then temperature uniformity is improved, but substrate positioning and support stability may be compromised
Solution Approach 1:
The susceptor employs multiple discrete support features distributed across the recessed pocket to provide both minimal contact area for temperature uniformity and sufficient support points for substrate stability. The segmented design allows optimization of both thermal and mechanical performance simultaneously.
Solution Approach 2:
The support features are designed to distribute the substrate weight evenly across multiple contact points within the recessed pocket, creating a stable support configuration. This equipotential distribution of mechanical load ensures substrate positioning accuracy and processing reliability while maintaining minimal total contact area for improved temperature uniformity.
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 improves thermal uniformity across the substrate, reduces hot spots, and enhances the quality of deposited layers by increasing the number of contact points while minimizing the contacting surface area, leading to better temperature control and processing results.
Implementation Method 1
The heated susceptor can then transfer heat to the substrate, primarily by radiation emitted by the susceptor
Implementation Method 2
reducing the contacting surface area between the susceptor and the substrate... minimizing conductive heat transfer
Data Source
AI summary
Embodiments of the present disclosure generally relate to a susceptor for thermal processing of semiconductor substrates. In one embodiment, the susceptor includes an inner region having a pattern formed in a top surface thereof, the pattern including a plurality of substrate support features separated by a plurality of venting channels. The susceptor includes a rim surrounding and coupled to the inner region, wherein the inner region is recessed relative to the rim to form a recessed pocket configured to receive a substrate. The susceptor includes a plurality of bumps extending radially inward from an inner diameter of the rim, the plurality of bumps configured to contact an outer edge of a substrate supported by the plurality of substrate support features for positioning the substrate within the recessed pocket.