Silicon Wafer Laminated Material Removal via Abrasive Blasting
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Solution Overview
Problem
Conventional methods for removing laminated materials from silicon wafers are inefficient, environmentally harmful, and cause damage to the substrate, making them costly and time-consuming.
Innovation Solution
A method involving the use of an abrasive with a density of 2.0 g/cm3 to 3.0 g/cm3 and a Mohs hardness of 9 to 11, such as boron carbide, is sprayed onto the silicon wafer using a blasting machine to forcibly peel off the laminated materials, while minimizing damage to the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If etching using alkaline and acidic agents is performed to remove laminated materials, then the laminated materials can be removed, but the process takes a long time, causes environmental problems, and erodes the silicon wafer substrate
Solution Approach 1:
The patent replaces chemical etching with mechanical blasting using abrasive particles. Compressed air propels abrasive grains (such as aluminum oxide or silicon carbide) at high speed to mechanically remove laminated materials from the silicon wafer surface, eliminating the need for chemical agents and significantly reducing processing time while improving productivity
Solution Approach 2:
The patent utilizes pneumatic power (compressed air) to drive the abrasive blasting process. The compressed air system propels abrasive particles through a nozzle onto the silicon wafer surface, enabling efficient mechanical removal of laminated materials without chemical erosion, thus solving both the efficiency and environmental problems
2Shape
If direct polishing is performed on the silicon wafer surface, then the surface can be smoothed, but the laminated materials with various hardnesses cannot be uniformly removed
Solution Approach 1:
The patent changes the removal mechanism from mechanical polishing (surface contact) to pneumatic abrasive blasting (projectile impact). By controlling abrasive particle size, compressed air pressure, and blasting duration, the process achieves uniform removal of various hard materials (SiO2, SiC, Si3N4, metals) while maintaining surface smoothness, solving the uniformity problem
3Manufacturing precision
If conventional sand blasting with alumina or silicon carbide is used, then laminated materials can be removed, but the apparatus is complex and the process is costly
Solution Approach 1:
The patent extracts and utilizes readily available compressed air (already present in semiconductor manufacturing facilities) to power the abrasive blasting process. This eliminates the need for complex chemical etching systems or specialized blasting equipment, simplifying the apparatus while maintaining effective laminated material removal
Solution Approach 2:
The patent uses consumable abrasive grains (alumina, silicon carbide) that are inexpensive and can be continuously supplied via compressed air. These disposable abrasives replace expensive chemical etchants and complex reusable equipment, reducing overall process cost while maintaining removal effectiveness
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 efficiently removes laminated materials from silicon wafers at a low cost, with minimal environmental impact and without causing significant damage to the substrate, thereby improving the reuse of intermediately discharged silicon wafers.
Implementation Method 1
spraying an abrasive having a density of 2.0 g/cm3 or more and less than 3.0 g/cm3 and a Mohs hardness of 9 or more and less than 11 to the surface of the intermediately discharged silicon wafer to forcibly peel off the laminated material
Implementation Method 2
spraying an abrasive... to forcibly peel off the laminated material on the surface
Data Source
AI summary
Provided is a method for removing a laminated material on a surface of a silicon wafer capable of considerably efficiently removing a laminated material on a surface of a silicon wafer at a low cost with a simple apparatus without a negative effect on environment or a serious damage on the silicon wafer as a substrate. A blasting process was performed by spraying boron carbide (B4C) having a particle size of #220 as an abrasive on a laminate surface of a laminated material of an intermediately discharged silicon wafer using a blasting machine (dry type that sprays a dry abrasive, and a gravity type that sprays the abrasive fallen from a tank of the abrasive due to gravity on a compressed air) under spray conditions of a spray distance=120 mm and a spray pressure=0.2 MPa for five seconds.