Wafer Guide and Susceptor Heating for Uniform Vapor Phase Growth
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Solution Overview
Problem
Existing vapor phase growth apparatuses face issues with film thickness variation, carrier concentration variation, and temperature inconsistencies during film formation on wafers due to problems like wafer offset and temperature variations, leading to degraded film formation accuracy.
Innovation Solution
The apparatus includes a susceptor with a wafer support portion and guide support portion, temperature sensors, and controlled heating elements to maintain temperature uniformity and prevent wafer offset, using a control unit to adjust heating based on temperature measurements from multiple sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single heating portion is used to heat the susceptor, then the device complexity is reduced, but the temperature uniformity across the wafer deteriorates
Solution Approach 1:
The heating portion is divided into multiple independent heating elements (first heating portion and second heating portion) positioned at different radial locations. Each heating element can be independently controlled to compensate for temperature variations across the wafer surface, thereby improving temperature uniformity without significantly increasing overall device complexity.
Solution Approach 2:
Different regions of the susceptor are heated by dedicated heating portions located at corresponding radial positions. The first heating portion heats the outer region while the second heating portion heats the inner region, creating localized heating zones that collectively achieve uniform temperature distribution across the entire wafer surface.
2Manufacturing precision
If the wafer guide is positioned close to the wafer edge, then the film formation accuracy is improved, but the risk of wafer offset increasing deteriorates
Solution Approach 1:
The wafer guide is positioned to extend slightly beyond the wafer edge in the radial direction, creating a preliminary mechanical constraint that prevents the wafer from offsetting during rotation. This preventive positioning ensures the wafer remains properly aligned throughout the film formation process, maintaining both film formation accuracy and preventing wafer offset.
3Measurement precision
If multiple temperature sensors and heating portions are used, then the temperature control precision is improved, but the device complexity increases
Solution Approach 1:
The temperature control system is segmented into multiple independent sensing and heating units positioned at different radial locations. Each temperature sensor monitors its local region and works with its corresponding heating portion, allowing distributed temperature control that improves measurement precision while keeping each control unit relatively simple.
Solution Approach 2:
Temperature sensors provide real-time feedback about the thermal state at different radial positions, which is used to dynamically adjust the heating portions. This feedback mechanism enables precise temperature control across the wafer surface, with each heating portion responding to local temperature conditions measured by its corresponding sensor.
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 maintains film thickness uniformity and carrier concentration consistency, preventing wafer offset and enhancing film formation accuracy by controlling temperature differences across the wafer surface.
Implementation Method 1
a first heating portion and a second heating portion capable of heating the susceptor
Implementation Method 2
a first temperature sensor and a second temperature sensor capable of measuring a temperature of the wafer
Data Source
AI summary
A vapor phase growth apparatus of an embodiment has a susceptor supporting a wafer, and a ring-shaped wafer guide surrounding the wafer. The susceptor has a wafer support portion supporting the wafer from below, a guide support portion supporting the wafer guide from below, and an inward portion positioned on an inward side in a radial direction from the wafer support portion. An upper surface of the inward portion is positioned below a wafer contact surface of the wafer support portion. The wafer contact surface is positioned above a guide contact surface of the guide support portion. During film formation processing, a control unit measures a temperature of a part in the wafer overlapping the wafer support portion by a first temperature sensor, measures a temperature of a part in the wafer overlapping the inward portion by a second temperature sensor.