Laser Modified Support Substrate for SAW Device Cutting
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Solution Overview
Problem
The existing methods for fabricating acoustic wave devices, such as surface acoustic wave (SAW) devices, result in oblique break and chipping of the piezoelectric substrate due to the cutting process, leading to reduced productivity and increased costs.
Innovation Solution
A method involving bonding a support substrate to a piezoelectric substrate, forming a modified region in the support substrate using a laser beam, and cutting both substrates in this modified region, where the distance from the boundary face to the edge of the modified region is optimized between 20 μm and 69 μm to minimize chipping and enhance cutting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cutting process is performed on the piezoelectric substrate, then the substrate can be separated into individual chips, but oblique break and chipping occur reducing manufacturing precision
Solution Approach 1:
A modified region is formed in advance within the support substrate at the intended cutting location using laser irradiation. This preliminary modification creates a predetermined cutting path that guides subsequent cutting, ensuring accurate separation without chipping or oblique breaks while maintaining high productivity
Solution Approach 2:
A support substrate is introduced as an intermediary layer between the piezoelectric substrate and the cutting tool. The modified region in the support substrate acts as a mediator that enables clean cutting by preventing direct contact between the cutting tool and the fragile piezoelectric substrate, thereby eliminating chipping
2Productivity
If the modified region is formed too close to the boundary face, then cutting efficiency increases, but chipping occurs at the boundary
Solution Approach 1:
The distance parameter from the boundary face to the modified region is optimized to a specific range (20-69 μm). This parameter change balances cutting efficiency with boundary integrity, allowing fast cutting while preventing chipping at the boundary face through controlled laser modification depth
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 significantly reduces chipping and oblique break rates, increases processing speed, and lowers the cost of SAW device production by ensuring the support substrate is easily cut while maintaining substrate strength, with chipping rates reduced to less than 2.5% when the distance is within the specified range.
Implementation Method 1
forming a modified region in the support substrate by irradiation of a laser beam
Data Source
AI summary
A method of fabricating an acoustic wave device includes: bonding a support substrate to a piezoelectric substrate on which an IDT is to be formed; forming a modified region in the support substrate by irradiation of a laser beam; and cutting the support substrate and the piezoelectric substrate in the modified region, wherein a distance from a boundary face between the support substrate and the piezoelectric substrate to an edge portion of the modified region at the boundary face side is greater than or equal to 20 μm and less than 69 μm.