Laser Processing Silicon Wafer Cutting Force and Particle Control
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Solution Overview
Problem
Conventional laser processing methods can cause particle formation and require significant external force to cut objects, especially when cutting through metal film surfaces.
Innovation Solution
A laser processing method that forms weakened regions of predetermined depth on the opposite face of the object along the cutting line, using multiphoton absorption to prevent particle occurrence and facilitate cutting with minimal external force by creating modified regions within the object, such as semiconductor substrates, which can be cut accurately using these weakened regions as a starting point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the modified region is formed closest to the other face (metal film surface) to enable cutting with small external force, then the cutting force is reduced, but particles occur from the modified region
Solution Approach 1:
A weakened region is formed in advance on the metal film surface before cutting, creating a predetermined separation path that guides the cutting process and prevents particle generation from modified regions
Solution Approach 2:
The function of creating a cutting start point is extracted from the modified region and implemented separately through a weakened region formed on the metal film surface, allowing the modified region to be positioned optimally without causing particle occurrence
2Manufacturing precision
If multiple rows of modified regions are formed within the semiconductor substrate, then cutting precision is improved, but the complexity of the processing increases
Solution Approach 1:
The cutting process is segmented into two distinct functions: modified regions formed within the semiconductor substrate to provide precision, and a weakened region formed on the metal film surface to enable clean separation, dividing the complex process into manageable stages
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
Prevents particle formation and allows for precise cutting of objects with reduced external force, maintaining control over the cutting process and minimizing damage to the front face.
Implementation Method 1
Each modified region is formed by generating multiphoton absorption or other kinds of optical absorption within the object by irradiating the object with laser light
Data Source
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AI summary
While six rows of molten processed regions 131, 132 to become a cutting start point are formed within a silicon wafer 11 along a line to cut 5, a weakened region 18 is formed in a rear face 21 of an object to be processed 1 along the line to cut 5 when forming the molten processed region 131 closest to the rear face 21. Since the molten processed regions 131, 132 are thus formed within the silicon wafer 11, particles can be prevented from occurring from the molten processed regions 131, 132. Also, since the weakened region 18 having a predetermined depth is formed on the rear face 21 of the object 1 along the line to cut 5, the object 1 can be cut along the line to cut 5 with a relatively small external force.