Wafer Susceptor Groove Structure for Uniform III-V Nitride Heating
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Solution Overview
Problem
Existing graphite discs in MOCVD devices experience uneven heating of wafers due to centrifugal forces, leading to poor heating uniformity and wavelength variations in III-V group nitride wafers, which affect the quality and yield of semiconductor manufacturing.
Innovation Solution
A wafer susceptor with a groove bottom design that includes a first region close to the center and a second region away from the center, featuring a convex structure with a curved surface and an uncovered area, adjusted to maintain a consistent gap with the wafer, reducing the impact of centrifugal forces and ensuring even thermal distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a convex groove is used to match the convexity of the epitaxial wafer, then the wafer can be securely held during rotation, but the gap between the wafer and groove bottom becomes large away from the center, causing uneven heating
Solution Approach 1:
The groove bottom is divided into multiple regions with different convex structure heights. The first region (near center) has a first average height while the second region (away from center) has a second average height that is greater than the first. This local differentiation compensates for the centrifugal force effect at different radial positions, maintaining uniform heating across the entire wafer surface while preserving secure holding during rotation.
2Ease of manufacture
If the groove bottom is made flat to simplify manufacturing, then production cost decreases, but the wafer experiences uneven heating due to centrifugal force during high-speed rotation
Solution Approach 1:
Instead of a completely flat groove bottom, the invention introduces convex structures with varying heights in different radial regions. This localized modification maintains manufacturing feasibility while effectively compensating for centrifugal force-induced uneven heating, achieving a balance between manufacturing simplicity and thermal uniformity.
3Temperature
If the convex structure height is increased away from the center to compensate for centrifugal force, then heating uniformity improves, but the manufacturing precision requirements increase
Solution Approach 1:
The groove bottom features different convex structure heights at different radial positions. The first region (near center) has a first average height and the second region (away from center) has a second average height greater than the first. This graduated height distribution naturally compensates for centrifugal force variations while maintaining reasonable manufacturing precision requirements through systematic design.
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 design improves heating uniformity and wavelength uniformity of epitaxial wafers, enhancing the quality and yield of semiconductor manufacturing by maintaining stable temperature and airflow, thus addressing the issues of uneven heating and centrifugal force-induced gaps.
Implementation Method 1
a graphite disc with a substrate is heated by radiation using a heating wire in a MOCVD reaction chamber
Implementation Method 2
since the wafer susceptor rotates at a high speed in a growth process of the wafer, the wafer is affected by a centrifugal force, and the wafer moves in a direction away from a center C of the wafer susceptor
Data Source
AI summary
Disclosed is a wafer susceptor. A groove bottom of the wafer susceptor is divided by a first dividing line passing through a center of a groove into a first region close to a center of the wafer susceptor and a second region away from the center of the wafer susceptor. The groove bottom includes a groove bottom surface and a convex structure formed on the groove bottom surface. An average height of the convex structure located in the second region is greater than that of the convex structure located in the first region. A design structure of the groove bottom of the wafer susceptor well matches a warped III-V group nitride wafer in an active region epitaxial process.