Induction Heating Susceptor Segmentation for Wafer Uniformity
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Solution Overview
Problem
Existing induction heating systems face challenges in uniformly heating large-diameter wafers, particularly with batch-type heating systems, where heat generation is uneven due to the skin effect, making it difficult to achieve efficient and precise heat treatment.
Innovation Solution
The induction heating apparatus employs a solenoid coil with inductive-heating target members arranged perpendicularly to its core axis, housed in a holder with magnetic permeability and heat conductivity, and configured with varying diameters and thicknesses to stabilize heat distribution, using different frequencies for the electric current to optimize heat generation across the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a lateral batch-type induction heating coil is used to heat large wafers, then heating efficiency is improved, but uniform heating deteriorates due to skin effect causing excessive heat at outer edges and insufficient heat at center
Solution Approach 1:
The susceptor is divided into multiple segments with different thicknesses: a first susceptor portion with smaller thickness at the outer edge region and a second susceptor portion with larger thickness at the center region. This segmentation allows the outer edge to generate more heat (compensating for skin effect) while the center generates less heat, achieving uniform temperature distribution across the wafer surface.
Solution Approach 2:
Different regions of the susceptor are given different local properties through variable thickness design. The outer edge region has reduced thickness to decrease heat generation, while the center region has increased thickness to enhance heat generation. This local quality variation directly addresses the non-uniform heating problem caused by skin effect.
2Manufacturing precision
If a single-wafer heating system is used, then heating uniformity is improved, but processing efficiency deteriorates
Solution Approach 1:
The susceptor is segmented into multiple heating zones corresponding to different radial positions on the wafer. Each segment can be independently optimized for its local heating requirements, enabling uniform heating across the entire wafer surface even when processing multiple wafers simultaneously in a batch configuration.
Solution Approach 2:
The invention transitions from a single-layer susceptor to a multi-layer stacked configuration where multiple susceptors are arranged in the vertical dimension. This allows batch processing of multiple wafers while maintaining uniform heating through the vertically stacked susceptor structure with varying thicknesses at different radial positions.
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 configuration enables high-precision uniform heating of large-diameter wafers by adjusting heat generation rates and capacities, effectively addressing the uneven heating issues in batch-type systems.
Implementation Method 1
heats an inductive-heating target member using a magnetic flux generated from a solenoid coil
Implementation Method 2
heats the wafer using a radiation heat of the inductive-heating target member
Implementation Method 3
a path for transmitting a magnetic flux emitted from the induction heating coil is provided on a plate surface of the heat generator
Implementation Method 4
heats a wafer using a radiation heat of the inductive-heating target member
Data Source
AI summary
To provide an induction heating apparatus that employs a batch-type heating system for heating a large-diameter wafer and can perform uniform heating with a high precision, an induction heating apparatus (10) that heats an inductive-heating target member using a magnetic flux generated from a solenoid-type induction heating coil (18) and heats a wafer (40) using the heat generated from the inductive-heating target member, wherein a plurality of inductive-heating target members 14 (14a, 14b, and 14c) of which principal surface is arranged perpendicularly to a core axis direction of the induction heating coil (18) are interspersed. In the induction heating apparatus (10) described above, a susceptor (12) may be configured by housing the inductive-heating target member (14) in a single holder (16) made of a member having magnetic permeability and heat conductivity.