Susceptor Contact Structure for Uniform Substrate Heating
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Solution Overview
Problem
Existing susceptors for semiconductor substrates fail to maintain uniform temperature profiles across the substrate surface during thermal processing, leading to reduced quality of deposited layers due to temperature non-uniformities near the edges and center.
Innovation Solution
The susceptor design incorporates structures such as wedges, bumps, and insulating separators to reduce the contacting surface area between the substrate and the susceptor, primarily by using elevated features and thermally insulating materials to minimize conductive heat transfer and enhance radiant heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the susceptor uses a large contacting surface area to support the substrate, then the substrate is well-supported, but temperature non-uniformities occur across the substrate surface
Solution Approach 1:
The susceptor surface is segmented into discrete contact points (protrusions) rather than a continuous large surface, reducing the total contacting area while maintaining support functionality. This segmentation prevents excessive heat conduction from creating temperature non-uniformities while still providing adequate mechanical support for the substrate.
Solution Approach 2:
The susceptor design implements local quality by creating specific elevated protrusion structures at predetermined locations rather than using a uniform surface. These localized contact points provide targeted support while minimizing the overall contact area, thereby reducing conductive heat transfer and improving temperature uniformity across the substrate.
2Temperature
If the susceptor heating power is increased to maintain uniform temperature, then temperature uniformity improves, but hotspots form near the edges and center
Solution Approach 1:
The invention extracts or removes the harmful conductive heat transfer pathway by reducing the contacting surface area between susceptor and substrate. By taking out the excessive contact interface, the harmful effect of conductive heating that causes hotspots is eliminated, allowing the substrate to be heated more uniformly through radiation without localized overheating.
Solution Approach 2:
The invention converts the harmful effect of conductive heat transfer into a beneficial reduction of hotspot formation. By deliberately reducing the contact area, the design uses the reduction in conductive heating (which would normally be harmful) to prevent hotspot formation and achieve more uniform temperature distribution across the substrate surface.
3Temperature
If the contacting surface area is reduced to prevent hotspots, then temperature uniformity improves, but substrate support stability may be compromised
Solution Approach 1:
The susceptor protrusions are designed with specific geometric characteristics (height, width, spacing) that create an optimal balance between support and thermal isolation. The dynamic geometry of these structures allows them to provide adequate mechanical support while maintaining minimal contact area for heat transfer.
Solution Approach 2:
The invention changes the physical parameters of the susceptor-substrate interface by reducing contact area through protrusion structures. By adjusting parameters such as protrusion height, width, and spacing, the design achieves optimal balance between support stability and temperature uniformity, preventing both excessive contact (hotspots) and insufficient contact (poor 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
This design improves thermal uniformity by reducing conductive heating, preventing hotspots, and ensuring more uniform temperature control, thereby enhancing the quality of deposited layers on semiconductor substrates.
Implementation Method 1
The heated susceptor can then transfer heat to the substrate, primarily by radiation emitted by the susceptor
Implementation Method 2
Each quartz insulating separator contacting two wedges and the inner edge of the outer rim
Data Source
AI summary
In one embodiment, a susceptor for thermal processing is provided. The susceptor includes an outer rim surrounding and coupled to an inner dish, the outer rim having an inner edge and an outer edge. The susceptor further includes one or more structures for reducing a contacting surface area between a substrate and the susceptor when the substrate is supported by the susceptor. At least one of the one or more structures is coupled to the inner dish proximate the inner edge of the outer rim.