Porous Sheet Laser Processing Suction Table Biting
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Solution Overview
Problem
In laser processing methods, the holding member directly secured onto a suction table can cause strong bending stress when separated, leading to unwanted cutting of objects along the line to cut from the modified region, resulting in particle formation from rubbing cut sections.
Innovation Solution
A porous sheet with a lower Young's modulus than the suction table is interposed between the holding member and the suction table to reduce the biting effect, allowing for accurate formation of a modified region as a cutting start point without excessive bending stress, and the sheet's lower friction, light absorption, and higher transmittance or reflectance properties prevent damage and maintain object flatness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the holding member is directly secured onto the suction table by suction, then the object can be held firmly for laser processing, but the holding member bites into the fine pores of the suction table, causing strong bending stress when separated, which cuts the object along the line to cut from the modified region
Solution Approach 1:
A porous sheet is introduced as an intermediary layer between the holding member and the suction table. This sheet allows suction to hold the object firmly during processing while preventing the holding member from biting into the suction table's fine pores. When separation occurs, the sheet reduces the bending stress transmitted to the object, preventing unwanted cutting along the modified region.
2Ease of operation
If the holding member is directly secured onto the suction table, then suction securing is effective, but when forcibly separated, the cut sections rub against each other producing particles
Solution Approach 1:
The porous sheet serves as a mediator that enables effective suction securing during laser processing while facilitating cleaner separation. The sheet's structure allows the holding member to be secured firmly during processing, and upon release, it reduces the friction and contact between cut sections, thereby minimizing particle generation from rubbing.
3Object-affected harmful factors
If a porous sheet with lower Young's modulus is interposed between the holding member and suction table, then bending stress is reduced preventing unwanted cutting, but additional components increase device complexity
Solution Approach 1:
A porous sheet is introduced as an intermediary layer between the holding member and the suction table. This sheet allows suction to hold the object firmly during processing while preventing the holding member from biting into the suction table's fine pores. When separation occurs, the sheet reduces the bending stress transmitted to the object, preventing unwanted cutting along the modified region.
4Object-affected harmful factors
If the sheet has lower friction coefficient than the suction table, then the holding member bites less into the sheet, but the sheet may slip during processing
Solution Approach 1:
The sheet's friction coefficient is optimized to balance two requirements: low enough to reduce the biting effect on the holding member, yet high enough to maintain sufficient grip during laser processing. This parameter optimization prevents both excessive biting and slippage, achieving stable object positioning throughout the process.
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 the object from being cut along the line to cut from the modified region acting as a cutting start point, maintaining object flatness and preventing particle formation by minimizing bending stress and ensuring accurate cutting.
Implementation Method 1
the sheet has a Young's modulus lower than that of the suction table
Implementation Method 2
securing a holding member holding a wafer-like object to be processed onto a suction table of a vacuum chuck by suction
Implementation Method 3
irradiating the object with laser light while locating a converging point within the object, so as to form a modified region to become a cutting start point within the object along a line to cut in the object
Implementation Method 4
The modified region to become a cutting start point is formed by irradiating the object with laser light while locating a converging point within the object so as to generate optical absorption such as multiphoton absorption within the object
Implementation Method 5
the sheet has a coefficient of friction lower than that of the suction table
Data Source
AI summary
A laser processing method which can prevent an object to be processed from being cut along a line to cut from a modified region acting as a cutting start point when separating a suction table and a holding member from each other is provided. An expandable tape 23 holding an object to be processed 1 while being stuck to a frame 51 is secured by suction onto a suction table 52 of a vacuum chuck with a porous sheet 53 interposed therebetween. Since the sheet 53 has a Young's modulus lower than that of the table 52, the tape 23 is restrained from biting into fine pores of the sheet 53. As a consequence, even when the table 52 and tape 23 are separated from each other by releasing the suction securing after forming a modified region 7, no strong bending stress acts on the object 1. This can prevent the object 1 from being cut along a line to cut from the modified region 7 acting as a cutting start point when separating the table 52 and tape 23 from each other.