Laser Modification Layers for Wafer Thinning and Eccentric Edge Trimming
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Solution Overview
Problem
Conventional wafer thinning and edge trimming processes are inefficient due to frequent whetstone replacement and high water consumption, leading to increased running costs and potential wafer damage from sharp edge formation.
Innovation Solution
A substrate processing apparatus and method that uses laser-based peripheral and internal modification layers to facilitate efficient removal of the wafer's peripheral portion and thinning, eliminating the need for frequent whetstone replacement and water usage by forming modification layers to guide the removal process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional grinding methods using whetstones are used for wafer thinning and edge trimming, then processing can be performed, but frequent whetstone replacement is required and water consumption is high
Solution Approach 1:
The patent replaces the mechanical grinding system (whetstone contact method) with a laser-based system. The laser beam performs both thinning and edge trimming through optical energy rather than mechanical abrasion, eliminating the need for whetstone replacement and reducing maintenance frequency while maintaining processing efficiency
Solution Approach 2:
The patent changes the processing parameter from mechanical force to laser energy parameters. By controlling laser power, pulse duration, and scanning speed, the system achieves precise material removal without mechanical contact, solving the contradiction between processing efficiency and maintenance requirements
2Loss of substance
If conventional grinding methods are used for wafer processing, then material removal is achieved, but water consumption increases and disposal issues arise
Solution Approach 1:
The laser-based system replaces water-cooled mechanical grinding with a dry optical process. Material removal is achieved through laser ablation without requiring cooling water, thereby eliminating water consumption and associated disposal problems while maintaining effective material removal capability
Solution Approach 2:
The patent converts the laser's thermal energy, which could potentially cause damage, into a beneficial tool for precise material removal. By controlling the laser parameters, the thermal effect is harnessed to vaporize material cleanly without requiring water cooling, turning a potential harm into a benefit
3Manufacturing precision
If mechanical grinding is used for edge trimming, then peripheral removal is achieved, but sharp edges may form causing wafer damage
Solution Approach 1:
The laser system replaces mechanical grinding with optical ablation for edge trimming. This produces rounded edges through controlled material vaporization rather than mechanical cutting, eliminating sharp edges that could cause wafer damage while maintaining precise dimensional control
Solution Approach 2:
The patent uses laser parameter control (power, pulse width, scanning speed) to precisely control the edge trimming process. By adjusting these parameters, the system achieves smooth, rounded edges without the sharp edges produced by mechanical grinding, thereby preventing wafer damage while maintaining manufacturing precision
4Ease of manufacture
If laser-based processing is used for wafer thinning and edge trimming, then maintenance frequency is reduced and water disposal issues are eliminated, but new processing challenges arise
Solution Approach 1:
The laser system performs multiple functions (thinning and edge trimming) with a single device, simplifying the overall manufacturing process. The same laser beam, with adjusted parameters, handles both operations, reducing maintenance frequency and eliminating water disposal issues while maintaining operational simplicity
Solution Approach 2:
The patent implements feedback control to manage the complexity of laser processing. By monitoring processing results and adjusting laser parameters in real-time, the system maintains precise control over thinning and edge trimming operations, converting processing control complexity into manageable feedback loops that ensure consistent quality
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
The laser-based method reduces maintenance frequency, eliminates water disposal issues, and lowers operational costs while ensuring precise and efficient wafer processing.
Implementation Method 1
a peripheral modifying device forms a peripheral modification layer by radiating a laser beam for periphery to an inside of the first substrate along a boundary between a peripheral portion of the first substrate as a removing target and a central portion
Implementation Method 2
an internal modifying device forms an internal modification layer by radiating a laser beam for internal surface to an inside of the first substrate
Data Source
AI summary
A substrate processing apparatus includes a holder configured to hold a combined substrate; a peripheral modifying device configured to form a peripheral modification layer to an inside of a first substrate along a boundary between a peripheral portion and a central portion; an internal modifying device configured to form an internal modification layer to the inside of the first substrate along a plane direction; a holder moving mechanism configured to move the holder in a horizontal direction. The peripheral modifying device radiates laser light for periphery to the inside of the first substrate while moving the holder to perform eccentricity correction. The internal modifying device radiates laser light for internal surface without performing the eccentricity correction at least at a center portion of the inside of the first substrate.