Plasma Dicing Silicon Carbide Etch Stop Layer
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Solution Overview
Problem
Conventional sawing techniques are inadequate for dicing silicon carbide wafers due to their hardness, leading to defects, tool wear, and high costs, and are slow and generate heat, making them unsuitable for mass production of silicon carbide dies.
Innovation Solution
A method involving plasma dicing of silicon carbide substrates using an etch stop layer that is plasma etched through, allowing for the separation of individual dies by cleaving the etch stop layer, which is supported by a ceramic stabilization layer and metallization layers, and utilizing an interhalogen gas chemistry for efficient etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional sawing techniques are used to dice silicon carbide wafers, then the dicing process can be performed, but the tool wears quickly, generates heat, and produces defects due to the hardness of silicon carbide
Solution Approach 1:
The patent replaces the mechanical sawing system with a plasma-based etching system. Instead of using physical saw blades that mechanically cut through the silicon carbide, the invention uses plasma to chemically etch and separate the dies. This substitution eliminates the mechanical contact that causes tool wear, heat generation, and defects, while maintaining high dicing speed and producing defect-free results.
Solution Approach 2:
The patent changes the physical and chemical parameters of the dicing process by using plasma etching with specific chemistries (such as fluorocarbon-based plasmas) that have high etch rates for silicon carbide. The plasma parameters (power, pressure, gas flow) are optimized to achieve fast etching while maintaining clean, defect-free surfaces. This parameter change enables both high productivity and high reliability.
2Ease of manufacture
If conventional sawing techniques are used to dice silicon carbide wafers, then the dicing process can be performed, but tool wear is significant and costs are high
Solution Approach 1:
The patent replaces the mechanical sawing system with a plasma-based etching system. Instead of using physical saw blades that mechanically cut through the silicon carbide, the invention uses plasma to chemically etch and separate the dies. This substitution eliminates the mechanical contact that causes tool wear, heat generation, and defects, while maintaining high dicing speed and producing defect-free results.
3Productivity
If conventional sawing techniques are used to dice silicon carbide wafers, then the dicing process can be performed, but heat is generated making it unsuitable for mass production
Solution Approach 1:
The patent replaces the mechanical sawing system with a plasma-based etching system. Instead of using physical saw blades that mechanically cut through the silicon carbide, the invention uses plasma to chemically etch and separate the dies. This substitution eliminates the mechanical contact that causes tool wear, heat generation, and defects, while maintaining high dicing speed and producing defect-free results.
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 high-rate, low-cost, and defect-free dicing of silicon carbide wafers with vertical sidewalls, reducing tool wear and heat generation, facilitating mass production of silicon carbide dies.
Implementation Method 1
plasma dicing the silicon carbide substrate from the second side. The plasma dicing etches through the silicon carbide substrate
Implementation Method 2
etching through the silicon carbide substrate to expose the ceramic stabilization layer using an etch chemistry comprising an interhalogen compound comprising chlorine and fluorine
Data Source
AI summary
A method of forming a semiconductor device includes forming an active region in a first side of a silicon carbide substrate, the silicon carbide substrate having a second side opposite the first side and forming a contact pad at the first side. The contact pad is coupled to the active region. The method further includes forming an etch stop layer over the contact pad and plasma dicing the silicon carbide substrate from the second side. The plasma dicing etches through the silicon carbide substrate and stops on the etch stop layer. The diced silicon carbide substrate is held together by the etch stop layer. The diced silicon carbide substrate is attached on a carrier. The diced silicon carbide substrate is separated into silicon carbide dies by cleaving the etch stop layer.