Group III Nitride Crystal Substrate Polishing
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Solution Overview
Problem
Existing methods for processing group III nitride crystal substrates fail to adequately remove abrasive grains and impurities from the surface after polishing, leading to residual contamination, particularly when using slurry with abrasive grains other than SiO2 and Al2O3.
Innovation Solution
A method involving multiple stages of polishing with either basic or acidic polishing liquids, each with specific pH and oxidation reduction potential ranges, to effectively remove impurities from the group III nitride crystal surface, including the use of chelates to capture metallic ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polishing is performed with a slurry containing abrasive grains, then the surface of the group III nitride crystal can be mechanically polished, but abrasive grains and residues remain on the surface as impurities
Solution Approach 1:
The invention extracts and removes the harmful abrasive grains and residues from the crystal surface through chemical dissolution using acidic or basic polishing liquids, separating the polishing function from the contamination problem
Solution Approach 2:
The invention introduces an intermediary substance (acidic or basic polishing liquid) that mediates between the mechanical polishing process and the crystal surface, chemically dissolving and removing abrasive grains and residues that mechanical polishing alone cannot eliminate
2Object-generated harmful factors
If polishing liquid is used to remove abrasive grains, then surface cleanliness improves, but multiple polishing steps increase processing time
Solution Approach 1:
The invention merges the mechanical polishing function and chemical cleaning function into a single integrated process by using polishing liquids that simultaneously provide mechanical abrasion and chemical dissolution, eliminating the need for separate polishing and cleaning steps
Solution Approach 2:
The invention creates a universal polishing liquid that performs multiple functions: mechanical polishing, chemical dissolution of abrasive grains, and surface cleaning, thereby reducing the total number of processing steps and overall 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 method significantly reduces residual impurities on the surface of group III nitride crystal substrates, enhancing their purity and suitability for semiconductor devices by ensuring a cleaner interface for epitaxial growth and improved device performance.
Implementation Method 1
polishing with a basic polishing liquid that does not contain abrasive grains
Implementation Method 2
polishing with an acidic polishing liquid
Implementation Method 3
the basic polishing liquid can further include a chelate
Data Source
AI summary
There is provided a method of processing a surface of a group III nitride crystal, that includes the steps of: polishing a surface of a group III nitride crystal with a polishing slurry containing abrasive grains; and thereafter polishing the surface of the group III nitride crystal with a polishing liquid at least once, and each step of polishing with the polishing liquid employs a basic polishing liquid or an acidic polishing liquid as the polishing liquid. The step of polishing with the basic or acidic polishing liquid allows removal of impurity such as abrasive grains remaining on the surface of the group III nitride crystal after it is polished with the slurry containing the abrasive grains.