Diode Laser Spot Heating for Epitaxial Wafer Uniformity
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Solution Overview
Problem
Semiconductor substrates experience temperature non-uniformity during processing, leading to film thickness non-uniformity due to valleys formed at certain locations, despite precise heating control.
Innovation Solution
A thermal process chamber with a high-energy radiant source assembly that provides localized heating to cold regions on the substrate, using a combination of heating elements and a movable high-energy radiant source assembly to improve temperature uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heating lamps are used to heat the substrate, then the substrate can be heated to required temperature, but temperature non-uniformity occurs causing valleys at certain locations
Solution Approach 1:
The patent introduces a movable high-energy radiant source assembly that provides localized heating to specific regions of the substrate. This assembly can be positioned to target cold spots or valleys where additional heating is needed, creating non-uniform heating distribution that compensates for the uniform heating pattern of traditional lamps, thereby improving film thickness uniformity
Solution Approach 2:
The high-energy radiant source assembly is made movable along a track, allowing dynamic adjustment of its position to different locations on the substrate. This dynamic capability enables the system to adaptively heat different regions as needed, transforming the static heating pattern into a flexible, adjustable one that can eliminate temperature non-uniformity
2Measurement precision
If precise control over heating source is implemented, then substrate temperature can be controlled within strict tolerances, but valleys still form at certain locations
Solution Approach 1:
Even with precise overall temperature control, localized valleys form due to geometric or process factors. The movable high-energy radiant source assembly addresses this by providing targeted local heating to specific valleys or cold spots, allowing the system to maintain precise overall temperature control while simultaneously correcting local non-uniformities that affect deposition uniformity
3Manufacturing precision
If a high-energy radiant source assembly is added to provide localized heating, then temperature uniformity is improved, but device complexity increases
Solution Approach 1:
The high-energy radiant source assembly is designed to move along a track rather than requiring multiple fixed sources. This dynamic approach reduces system complexity compared to having multiple stationary heating elements, as a single movable source can service the entire substrate area sequentially, achieving temperature uniformity improvement with minimal additional components
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 reduces temperature non-uniformity and film thickness variations, enhancing deposition uniformity and substrate quality by focusing energy on specific areas during rotation.
Implementation Method 1
a high-energy radiant source assembly disposed over the first plurality of heating elements... provides localized heating to cold regions on the substrate
Implementation Method 2
a first plurality of heating elements disposed over the first dome... the first dome is disposed between the first plurality of heating elements and the substrate support
Data Source
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AI summary
A process chamber, comprising: a first transmissive member (112); a second transmissive member (114); a substrate support (102) disposed between the first transmissive member (112) and the second transmissive member (114); a first plurality of heating elements (104) disposed over the first transmissive member (112), wherein the first transmissive member (112) is disposed between the first plurality of heating elements (104) and the substrate support (102); a lid (116) disposed over the first plurality of heating elements (104); a support member (132) disposed on the lid (116); a support block (614) disposed on the support member (132); and a spot heating source assembly (108) disposed on the support block (614), wherein the spot heating source assembly (108) comprises a radiant spot heating source pointed at the substrate support (102).