Susceptor Support Shaft Design for Epitaxial Film Uniformity
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Solution Overview
Problem
Conventional single-wafer epitaxial growth apparatuses face challenges in achieving uniform in-plane resistivity distribution of epitaxial films due to susceptor deflection, which affects temperature uniformity and accuracy in temperature detection, leading to reduced wafer quality.
Innovation Solution
A susceptor support shaft with a support column, radially extending arms, and an arm connecting member, featuring four or more support pins for stable susceptor support while maintaining a smaller number of arms to ensure accurate temperature detection, thereby reducing susceptor deflection and enhancing resistivity uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of support pins is increased to suppress susceptor deflection, then manufacturing precision of epitaxial film is improved, but device complexity increases
Solution Approach 1:
The support function is segmented into multiple support pins (4 or more) distributed around the susceptor perimeter, with each pin providing localized support to prevent deflection at different locations. This segmentation allows the system to achieve uniform support without requiring a single complex support structure.
Solution Approach 2:
Support pins are strategically positioned at locations where deflection is most likely to occur (peripheral portions of the susceptor). The arm connecting member is designed to provide rigidity only where needed for support while maintaining transparency in the pyrometer detection path.
2Manufacturing precision
If the number of arms is increased to support more support pins, then manufacturing precision is improved, but measurement precision of temperature detection deteriorates
Solution Approach 1:
The support function is extracted from the arms and transferred to the support pins mounted on the arm connecting member. This allows the arms to be reduced in number (to 3 or fewer) to clear the pyrometer path, while the support pins (4 or more) provide the necessary support stability. The support function is taken out of the rotational arms and placed on the stationary arm connecting member.
Solution Approach 2:
The support structure transitions from a planar arm-based support to a three-dimensional configuration where support pins are mounted on the arm connecting member in a position that provides both mechanical support and clearance for pyrometer detection. The support pins extend radially outward to contact the susceptor while the arm connecting member remains in a plane that allows pyrometer access.
3Productivity
If rotation speed is increased to improve productivity, then susceptor deflection worsens due to centrifugal force, but manufacturing precision deteriorates
Solution Approach 1:
The support pins are positioned and configured to counteract the centrifugal force generated during rotation. By having 4 or more support pins distributed around the susceptor, the system creates a balanced support structure that compensates for the outward centrifugal force, preventing deflection even at high rotation speeds required for high productivity.
Solution Approach 2:
The support structure is designed to dynamically respond to rotational forces. The arm connecting member with multiple support pins provides flexible yet stable support that adapts to the centrifugal forces during rotation, maintaining susceptor flatness across a wide range of rotation speeds from slow heating to fast epitaxial growth.
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 suppresses in-plane resistance variation and ensures accurate temperature detection, resulting in high-quality epitaxial wafers with uniform resistivity distribution and improved temperature control during the epitaxial growth process.
Implementation Method 1
a plurality of halogen lamps 206 as heating sources are radially disposed in each of an upper region and a lower region of the chamber 201
Implementation Method 2
the susceptor support shaft 203 is rotated around the support column 207 as a central axis to rotate the susceptor 202 and the semiconductor wafer W
Implementation Method 3
a carrier gas, a growth source gas, a dopant gas, and the like are introduced as process gases from the supply port 204, such that the process gases flow in a laminar flow state along a surface of the semiconductor wafer W
Implementation Method 4
The recessed portions 211 are engaged with the support pins 210 of the arms 208, so that the susceptor 202 is positioned with respect to the susceptor support shaft 203
Data Source
AI summary
A susceptor support shaft for an epitaxial growth apparatus capable of forming a high quality epitaxial film by suppressing in-plane resistance variation of the epitaxial film due to deflection of a susceptor, wherein the susceptor support shaft supports a susceptor at an underneath portion of the susceptor in an epitaxial growth apparatus. The susceptor support shaft includes a support column located substantially coaxial with a center of the susceptor; a plurality of arms extending radially from the support column to positions under a peripheral portion of the susceptor; an arm connecting member connecting tips of the arms next to each other; and support pins extending from the arm connecting member, thereby supporting the susceptor.