Chip Dicing of Hard Substrates With Ultrasonic Pre-Grooving
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Solution Overview
Problem
Existing methods struggle to efficiently cut workpieces with substrates harder than monocrystalline Si substrates, such as SiC or sapphire, leading to increased chippings and inefficiencies due to clogging on the reverse side of the workpiece.
Innovation Solution
A method involving a first cutting blade that vibrates at an ultrasonic frequency to form a partial cut groove from the surface to short of the opposite surface, followed by a second cutting blade with smaller abrasive grains to complete the cut and divide the workpiece into chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cutting blade with small abrasive grain diameter is used to reduce chippings on the face side, then chippings on the face side are reduced, but the cutting blade clogs and becomes less efficient on the reverse side
Solution Approach 1:
The cutting process is divided into two separate stages: first forming cut grooves that terminate short of the reverse side, then performing the final dividing cut. This segmentation allows different cutting blades with optimized characteristics to be used for each stage, resolving the contradiction between face side precision and reverse side efficiency
Solution Approach 2:
The first cutting blade performs preliminary cutting to form grooves that stop before reaching the reverse side, creating a prepared state for the second blade. This preliminary action removes material in a controlled manner, reducing the burden on the second blade and preventing clogging while maintaining face side quality
2Manufacturing precision
If a cutting blade with small abrasive grain diameter is used to cut harder substrates, then chippings are reduced, but the blade becomes clogged and less efficient
Solution Approach 1:
The cutting operation is segmented into two distinct phases using two different blades. The first blade with smaller grains creates grooves without penetrating fully, while the second blade completes the cut. This segmentation prevents the single blade from becoming clogged while maintaining precision
Solution Approach 2:
The first cutting blade performs a partial cut that stops short of completing the division, creating grooves that terminate before reaching the opposite surface. This partial action allows the use of small-grain blades for precision work without requiring them to complete the full cutting path, thereby preventing clogging
3Productivity
If full-cutting method is used to divide workpiece, then division is completed in one pass, but chippings occur on both face and reverse sides
Solution Approach 1:
The single-pass full cutting method is segmented into two sequential operations: first forming grooves that terminate short of the reverse side, then performing the final dividing cut from the reverse side. This segmentation eliminates chippings on both surfaces by ensuring the first blade does not reach the reverse side and the second blade cuts through pre-formed grooves
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
Reduces the number and size of chippings on both sides of the workpiece by utilizing a vibratory first blade and a second blade with smaller abrasive grains, effectively dividing harder substrates like SiC into chips.
Implementation Method 1
cutting the workpiece along each of the projected dicing lines with a first cutting blade as it is vibrating at a frequency in an ultrasonic band, to form a cut groove in the workpiece
Implementation Method 2
cutting off an uncut residual portion from the workpiece along each of the projected dicing lines with a second cutting blade different from the first cutting blade
Data Source
AI summary
A method of manufacturing a plurality of chips by dividing a workpiece having a substrate harder than a monocrystalline Si substrate includes a cut groove forming step of, while holding the workpiece on a holding table with a surface of the workpiece being exposed, cutting the workpiece along each of projected dicing lines with a first cutting blade as it is vibrating at a frequency in the ultrasonic band, to form a cut groove in the workpiece such that the cut groove extends from the surface of the workpiece and terminates short of another surface of the workpiece, and a dividing step of, while holding the workpiece on the holding table with the other surface of the workpiece being exposed, cutting off an uncut residual portion from the workpiece along each of the lines with a second cutting blade to divide the workpiece into a plurality of chips.