SiC Wafer Separation Process for Warpage-Suppressed Device Fabrication
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Solution Overview
Problem
SiC semiconductor devices are affected by warpage due to internal stress in SiC single crystal wafers, leading to production challenges such as patterning difficulties, adsorption errors, and cracking, which are not adequately addressed by existing methods.
Innovation Solution
A method involving a growth step to form a growth layer on SiC single crystals, followed by a device formation step to create a portion of the semiconductor device, and a separation step to separate this portion from the wafer, while incorporating heat treatment in Si and C atmospheres to suppress warpage-related defects like strain, crystal defects, and basal plane dislocations, and using laser irradiation for separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If SiC single crystal wafers with larger thickness are used to suppress warpage, then wafer stability is improved, but material loss increases and economic efficiency deteriorates
Solution Approach 1:
The invention divides the thick SiC wafer into multiple thinner wafers by introducing a separation layer at a predetermined depth. This segmentation allows each resulting wafer to have reduced thickness and suppressed warpage while minimizing overall material loss compared to using uniformly thick wafers.
Solution Approach 2:
The separation layer is formed in advance during the crystal growth process using laser irradiation before the wafers are fully processed. This preliminary action enables subsequent easy separation into multiple thin wafers, preventing warpage issues before they affect production.
2Manufacturing precision
If heat treatment is performed in atmosphere containing Si and C elements, then crystal quality is improved, but process complexity increases
Solution Approach 1:
The invention combines multiple functions into the heat treatment process: warpage suppression, crystal defect elimination, and separation layer formation are all achieved in a single heat treatment step with Si and C elements, rather than requiring separate processes for each function.
Solution Approach 2:
The heat treatment process utilizes controlled changes in temperature, atmosphere composition (Si and C elements), and time parameters to achieve multiple objectives simultaneously. By optimizing these parameters, the process improves crystal quality while managing complexity through systematic control.
3Manufacturing precision
If warpage is suppressed through proper wafer thickness control, then device production quality is improved, but productivity decreases due to thicker wafers requiring longer processing
Solution Approach 1:
By segmenting thick wafers into multiple thinner wafers, each wafer can be processed more quickly while maintaining quality standards. The segmentation enables parallel processing of multiple thin wafers, improving overall productivity compared to processing fewer thick wafers.
Solution Approach 2:
The separation layer is created in advance during crystal growth, allowing subsequent separation into optimally thick wafers that balance quality and processing speed. This preliminary action enables faster processing without compromising the quality improvements gained from controlled thickness.
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 method enables the production of high-quality SiC semiconductor devices with suppressed warpage, reducing material loss and enhancing economic efficiency by repeated production of high-quality wafers with improved characteristics.
Implementation Method 1
the workpiece is heat-treated in an atmosphere containing Si and C elements
Implementation Method 2
using laser irradiation for separation
Data Source
AI summary
An object of the present invention is to provide a high-quality SiC semiconductor device. In order to solve the above problem, the present invention comprises a method for producing a SiC semiconductor device, comprising a growth step of forming a growth layer on a workpiece comprising SiC single crystals, a device formation step of forming at least a portion of a SiC semiconductor device in the growth layer, and a separation step of separating at least a portion of the SiC semiconductor device from the workpiece.