Nitride Semiconductor Substrate Warpage Control
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Solution Overview
Problem
Nitride semiconductor substrates with non-uniform warpage shapes pose challenges in adhesion to substrate holders, leading to non-uniform temperature distribution and film thickness during epitaxial growth, which affects the quality of the grown films and increases manufacturing costs.
Innovation Solution
The introduction of a specific warpage parameter in the diameter direction, where the difference between the maximum and minimum warpage values (Hmax−Hmin) is set to be 30 μm or less, ensures improved adhesion and uniform temperature distribution by using a substrate holder with a symmetrical warpage shape matching the substrate's warpage, thereby achieving uniform film thickness and improved device production yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a nitride semiconductor substrate with non-uniform warpage is used, then the substrate can be obtained from conventional growth processes, but the adhesion to the substrate holder deteriorates and temperature distribution becomes non-uniform
Solution Approach 1:
The patent applies parameter changes by controlling the warpage characteristics of the substrate within specific ranges (maximum warpage amount of 10μm or less, and warpage difference between center and peripheral portions of 5μm or less). This quantitative parameter control ensures both manufacturability and uniform temperature distribution during epitaxial growth, resolving the contradiction between ease of manufacture and manufacturing precision.
2Device complexity
If the substrate warpage is not controlled, then the substrate can be produced with less manufacturing complexity, but the film thickness uniformity during epitaxial growth deteriorates
Solution Approach 1:
The patent establishes specific parameter ranges for substrate warpage (maximum warpage ≤10μm, peripheral-warpage difference ≤5μm) that can be achieved through conventional growth processes. By controlling these parameters, the patent ensures uniform film thickness during epitaxial growth without requiring complex substrate production methods, thus resolving the contradiction between device complexity and manufacturing precision.
3Ease of manufacture
If a substrate holder with uniform warpage shape is used, then the holder can be manufactured with symmetrical design, but the adhesion to substrates with non-uniform warpage deteriorates
Solution Approach 1:
The patent enables the use of substrate holders with uniform warpage shapes by controlling the substrate warpage parameters to specific ranges. This parameter control allows symmetrical holder design for ease of manufacture while ensuring reliable adhesion, as the controlled substrate warpage falls within the acceptable range for uniform holders, resolving the contradiction between ease of manufacture and reliability.
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 approach enhances the adhesion of the substrate to the holder, ensures a uniform temperature distribution, and results in uniform film thickness characteristics, improving the yield and quality of nitride semiconductor devices.
Implementation Method 1
ensures a uniform temperature distribution by using a substrate holder with a symmetrical warpage shape matching the substrate's warpage
Implementation Method 2
causing epitaxial growth on a base substrate, by using vapor-phase deposition methods such as a metal-organic vapor phase (MOVPE)
Data Source
AI summary
To improve an adhesion to a substrate holder, and improve a device production yield by uniformizing a temperature distribution in a surface of a substrate and uniformizing characteristics such as a film thickness. When a concave warpage is set to be negative on a substrate front side, and a convex warpage is set to be positive on the substrate front side, then a line segment is drawn from one end of a substrate rear surface to the other end of the substrate rear surface, passing through a substrate center line, and a substrate is sliced by this line segment in a substrate thickness direction, a maximum value of shortest values of a distance from an arbitrary point on the drawn line segment to a rear side outline in a sliced surface, is defined as warpage H in a diameter direction, and when the warpage H in the diameter direction is obtained in a substrate peripheral direction, with its maximum value set to be Hmax, and its minimum value set to be Hmin, the warpage H in the diameter direction is defined to satisfy Hmax−Hmin≦30 μm.