Semiconductor Dicing via Laser-Induced Cracks and Metal Film Removal
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Solution Overview
Problem
Existing dicing methods for semiconductor wafers with metal films on the bottom surface face issues such as burrs, metal dust clogging, high operational costs, and the need for expensive etching devices, particularly when using cutting blades, diamond wheels, or pulse laser beams.
Innovation Solution
A dicing method that involves removing the metal film using a diamond tool and then performing pulse laser beam irradiation, with precise control over the pulse laser beam to form cracks in the substrate, allowing for efficient dicing while minimizing the formation of burrs and dust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cutting blade is used to cut the semiconductor wafer, then the wafer can be divided into individual chips, but burrs appear on the bottom surface and metal dust clogs the blade
Solution Approach 1:
The patent replaces the mechanical cutting blade system with a laser beam system to perform dicing. The laser beam ( wavelength of 532 nm or 1064 nm) is focused onto the dicing line to form an altered layer in the substrate, which then allows clean separation without mechanical contact. This eliminates burr formation and metal dust generation while maintaining high dicing throughput.
2Productivity
If a diamond wheel or diamond blade is used for dicing, then the substrate can be divided, but the diamond tool becomes worn and needs frequent replacement
Solution Approach 1:
The patent replaces mechanical diamond tools with a laser beam system for dicing. The laser beam forms altered layers in the substrate along the dicing line through optical energy concentration, enabling separation without mechanical contact. This eliminates diamond tool wear and extends tool service life indefinitely, while maintaining high dicing throughput.
3Ease of manufacture
If a laser beam is used to melt or vaporize the metal film, then the metal can be removed, but processing dust and debris are generated
Solution Approach 1:
The patent changes the laser parameters (wavelength, pulse duration, power density) to selectively modify the substrate material rather than vaporize the metal film. By using wavelengths (532 nm or 1064 nm) and controlling pulse duration, the laser forms altered layers in the substrate below the metal film, causing the substrate to crack and separate along the dicing line. This parameter optimization eliminates processing dust generation while achieving effective metal film removal.
4Ease of manufacture
If an etching device is used to remove the metal film before dicing, then the metal film can be removed, but expensive equipment is required
Solution Approach 1:
The patent replaces expensive chemical etching devices with a laser beam system. The laser beam (532 nm or 1064 nm wavelength) is focused onto the substrate to form altered layers that enable dicing through crack propagation. This substitution eliminates the need for expensive etching equipment while achieving effective metal film removal and clean dicing separation.
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 method achieves high throughput and excellent dicing properties with low costs by removing the metal film through a metal processing operation and subsequent pulse laser beam irradiation, reducing the need for expensive equipment and minimizing product degradation.
Implementation Method 1
emitting a pulse laser beam synchronized with the clock signal to the groove portion of the substrate to be processed
Implementation Method 2
forming cracks in the substrate to be processed, the cracks reaching the substrate surface
Implementation Method 3
forming a groove portion by removing the metal film through a metal processing operation with a diamond tool
Data Source
AI summary
The present invention provides a dicing method that achieves excellent dicing properties at low costs by removing a metal film through a metal processing operation with a diamond tool and then performing pulse laser beam irradiation. The dicing method is a method of dicing a substrate to be processed, devices being formed in the substrate to be processed, a metal film being formed on one surface of the substrate to be processed. The dicing method includes: placing the substrate to be processed onto a first stage; forming a groove portion by removing the metal film through a metal processing operation with a diamond tool; placing the substrate to be processed onto a second stage; generating a clock signal; emitting a pulse laser beam synchronized with the clock signal to the groove portion of the substrate to be processed; moving the substrate to be processed and the pulse laser beam relative to each other; switching the pulse laser beam between irradiation and non-irradiation of the substrate to be processed on a light pulse basis by controlling passing and blocking of the pulse laser beam with a pulse picker in synchronization with the clock signal; and forming cracks in the substrate to be processed, the cracks reaching the substrate surface.