Indium Phosphide Substrate Edge Polishing for Residue Control
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Solution Overview
Problem
The surface roughness of indium phosphide substrates' edge parts is high, leading to contamination from residual grinding abrasives and polishing fluids, which can cause yield loss and degrade surface quality during epitaxial growth.
Innovation Solution
The indium phosphide substrate is manufactured with a surface roughness of 0.15 μm or less at the edge parts, achieved by chamfering and polishing with a #4000 grit size polishing film, followed by etching, to prevent residue migration and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the edge part is machined with conventional grinding and polishing methods, then the edge shape is formed, but the surface roughness becomes large causing residue accumulation and contamination
Solution Approach 1:
The patent changes the polishing parameters by using a finer grit size (#4000 or finer) and controlling the polishing pressure and speed to achieve a surface roughness Sq of 0.15 μm or less. This parameter optimization resolves the contradiction by enabling both proper edge shaping and low surface roughness that prevents residue accumulation.
Solution Approach 2:
The patent applies preliminary polishing treatment to the edge part before final cleaning processes. By pre-polishing the edge surface to low roughness, the subsequent cleaning processes become more effective at removing residues, and the edge surface itself becomes less prone to accumulating grinding abrasives and polishing fluids.
2Reliability
If polishing is performed to reduce surface roughness, then contamination is suppressed, but the processing time and complexity increase
Solution Approach 1:
The patent optimizes polishing parameters including using #4000 grit size or finer, controlling polishing pressure within specific ranges, and setting appropriate polishing speeds. These optimized parameters achieve the required surface roughness Sq ≤ 0.15 μm in a efficient manner, balancing contamination suppression with reasonable processing time.
Solution Approach 2:
The polished edge surface with low roughness has self-cleaning properties where residues are less likely to accumulate and easier to remove during standard cleaning processes. This reduces the need for additional specialized cleaning steps, thereby suppressing contamination while minimizing additional processing time.
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 suppresses contamination, improving the surface quality and yield of indium phosphide substrates and semiconductor epitaxial wafers by ensuring a smooth edge surface, enhancing the reliability of epitaxial growth processes.
Implementation Method 1
a surface roughness of an edge part of the substrate has a root mean square height Sq of 0.15 μm or less, as measured by a laser microscopy on the entire surface of the edge part
Implementation Method 2
a process of polishing the entire surface of the edge part of the indium phosphide wafer after the chamfering with a polishing film of #4000 grit size
Data Source
AI summary
Provided is an indium phosphide substrate, a method for manufacturing indium phosphide substrate, and a semiconductor epitaxial wafer capable of suppressing an occurrence of contamination of the surface of the indium phosphide substrate caused by residues at the edge part. An indium phosphide substrate, wherein a surface roughness of an edge part of the substrate has a root mean square height Sq of 0.15 μm or less, as measured by a laser microscopy on the entire surface of the edge part.