Silicon Carbide Substrate Thinning by Ion-Implanted Separation
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Solution Overview
Problem
The high Mohs' hardness of silicon carbide substrates leads to significant wear of grinding apparatuses during thinning, resulting in complete waste of the substrates and low economic benefits, as existing methods rely on grinding for thickness reduction.
Innovation Solution
A substrate thinning method involving ion implantation on the carbon surface of a silicon carbide substrate, followed by bonding to a second substrate and high-temperature annealing to generate internal stress for separation, allowing for reusability of the thinned substrate without the need for grinding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a grinding apparatus is used to thin the silicon carbide substrate, then the substrate thickness can be reduced to specified dimensions, but the grinding apparatus generates significant wear and the substrate is completely wasted
Solution Approach 1:
The substrate is segmented into two parts through selective separation: a thinned first substrate retaining the device and a separated first substrate that can be reused. This is achieved by forming a separation layer at a specific depth and selectively removing material above this layer, allowing the lower portion to be recovered and reused for subsequent device fabrication.
Solution Approach 2:
Instead of discarding the entire substrate after grinding, the invention recovers the lower portion (first substrate) that remains after separating the device layer. This recovered substrate can be reused for fabricating additional devices, significantly reducing material waste and improving economic benefits.
2Manufacturing precision
If a grinding apparatus is used to thin the silicon carbide substrate, then the substrate can be processed, but the high hardness of silicon carbide causes great wear to the grinding apparatus
Solution Approach 1:
The invention replaces the mechanical grinding process with a chemical etching process. By using selective etchants that react with silicon carbide at controlled rates, the substrate is thinned without the mechanical contact that causes wear. The etching process can be precisely controlled to achieve the desired thickness while minimizing damage to the grinding apparatus.
Solution Approach 2:
The invention changes the processing parameters from mechanical removal to chemical removal. By controlling etching temperature, etchant concentration, and processing time, the substrate can be thinned to precise dimensions without the wear associated with mechanical grinding. This parameter change transforms a wear-intensive process into a controlled chemical process.
3Productivity
If the substrate is thinned by grinding, then the thickness is reduced, but the substrate is completely wasted and economic benefits are low
Solution Approach 1:
The substrate is divided into a device layer and a reusable base layer through selective separation. The base layer (first substrate) retains sufficient thickness and quality to be reused for fabricating additional devices, thereby increasing overall substrate utilization and economic benefits while maintaining production efficiency.
Solution Approach 2:
The invention recovers the first substrate after device separation, allowing it to be reused for subsequent device fabrication cycles. This recovery process transforms a single-use substrate into a multi-use resource, significantly improving substrate utilization rates and economic returns without compromising processing efficiency.
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 reduces substrate waste, enhances economic benefits by reusing thinned substrates, and minimizes surface damage, achieving efficient and cost-effective thinning with improved surface flatness and reduced processing costs.
Implementation Method 1
performing ion implantation on the carbon surface of the first substrate
Implementation Method 2
performing high-temperature annealing on the bonded first substrate and the second substrate to combine ions implanted into the first substrate into gas
Implementation Method 3
high-temperature annealing is performed on the bonded first substrate and the second substrate to combine ions implanted into the first substrate into gas
Data Source
Figure 1
Figure 2(a)~2(k)
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AI summary
This application provides a silicon carbide substrate, a silicon carbide device, and a substrate thinning method thereof. The method includes: providing a first substrate, where the first substrate is a silicon carbide substrate, and the first substrate has a silicon surface and a carbon surface that are opposite to each other; forming a silicon carbide device on the silicon surface of the first substrate, and forming a protective layer on the silicon carbide device; performing ion implantation on the carbon surface of the first substrate; providing a second substrate; bonding an ionimplanted first substrate to the second substrate; performing high-temperature annealing on the bonded first substrate and the second substrate to combine ions implanted into the first substrate into gas; and performing separation at a position of ion implantation of the first substrate to obtain a thinned first substrate and a separated first substrate. According to the substrate thinning method in embodiments of this application, a substrate of the silicon carbide device does not need to be ground. The substrate thinning method is easier to operate. In addition, a separated first substrate after the substrate is thinned can be reused, and economic benefits are higher.