InP Single-Crystal Substrate Etching to Reduce Slicing Cracks
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Solution Overview
Problem
Existing methods for manufacturing group III-V compound semiconductor single crystal substrates face challenges in reducing the cracking defect rate during the slicing process.
Innovation Solution
The method involves growing a group III-V compound semiconductor single crystal using a crystal growth apparatus with a crucible and a heating element, where the interface between the crystalline solid and the raw material melt has a crossing angle of less than 90 degrees with respect to the crucible axis, and subjecting the substrate to a specific etching treatment to create a ripple-like pattern without positioning the wave source on the main surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional slicing process is used to manufacture group III-V compound semiconductor single crystal substrates, then the manufacturing process is simple, but the cracking defect rate is high
Solution Approach 1:
The patent applies preliminary action by performing etching treatment on the substrate surface before slicing. The etching process creates a ripple-like pattern that pre-releases residual stress in the crystal structure. This preliminary stress relief prevents cracking during the subsequent slicing process, thereby reducing the cracking defect rate without significantly complicating the manufacturing workflow
Solution Approach 2:
The patent changes the physical-chemical parameters of the substrate surface through etching treatment. By controlling etching time, temperature, and chemical composition, the surface morphology is modified to create a ripple-like pattern. This parameter change alters the stress distribution in the crystal, making it more resistant to cracking during slicing while maintaining manufacturing feasibility
2Reliability
If the interface between crystalline solid and raw material melt has a crossing angle of less than 90 degrees, then the cracking defect rate decreases, but the crystal growth control becomes more difficult
Solution Approach 1:
The patent introduces asymmetry by setting the interface crossing angle between the crystalline solid and raw material melt to less than 90 degrees relative to the crucible axis. This asymmetric angle creates a specific stress distribution pattern during crystal growth that reduces residual stress in the final substrate. The asymmetric geometry is carefully controlled to achieve stress relief while maintaining adequate crystal growth control through adjusted pulling speed and temperature gradients
3Manufacturing precision
If etching treatment is applied to create a ripple-like pattern, then the substrate quality improves, but the treatment time and process complexity increase
Solution Approach 1:
The patent optimizes etching parameters including chemical composition, temperature, and time to achieve the desired ripple-like pattern within a reasonable timeframe. By adjusting these parameters, the etching process efficiently creates the stress-relieving surface morphology without excessive treatment time. The specific etching conditions are tuned to balance substrate quality improvement with manufacturing efficiency
Solution Approach 2:
The patent applies etching treatment to create a ripple-like pattern that extends beyond the minimum required for stress relief. This partial excessive action ensures comprehensive coverage and uniform stress distribution across the substrate surface, guaranteeing quality improvement while the etching parameters are optimized to prevent excessive time consumption
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 effectively decreases the cracking defect rate during the slicing process and achieves a substrate with improved electrical and optical properties.
Implementation Method 1
a heating element that heats the crucible
Implementation Method 2
growing a crystalline solid on the raw material melt side of the seed crystal
Implementation Method 3
causes a reflection type incandescent electric lamp of 500 W to radiate light toward the main surface... and causes a reflection type incandescent electric lamp of 500 W to radiate light toward the main surface
Data Source
AI summary
This group III-V compound semiconductor single crystal substrate has a circular main surface, is an indium phosphide single crystal substrate, and has a ripple-like pattern visually recognized on the main surface by being subjected to designated treatment. The ripple-like pattern is a pattern corresponding to a part of ripples which concentrically spread from a wave source, and the wave source is not positioned on the main surface.