Semiconductor Wafer Dicing via Laser-Mechanical Hybrid Cutting
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Solution Overview
Problem
Conventional semiconductor wafer dicing methods, such as sawing, often result in chipping and cracking due to the mechanical stress involved, while laser cutting methods face challenges in precision and efficiency.
Innovation Solution
A method that combines laser cutting with mechanical sawing, where a laser cut is applied to the lateral boundaries of a saw street or a partial volume of the substrate, reducing the thickness to be cut by the saw and minimizing stress, thereby preventing chipping and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a saw is used to dice the substrate, then the substrate can be divided, but chipping and cracking occur on both sides of the sawing line
Solution Approach 1:
A laser cut is performed before mechanical sawing to create a starting point region and pre-fracture the substrate along the intended cut line. This preliminary action reduces the mechanical stress required during subsequent sawing, preventing chipping and cracking while enabling clean division of the substrate.
Solution Approach 2:
An expansion film is attached to the rear face of the substrate and used as an intermediary to apply controlled stress during the laser cutting process. The film expands to generate a fracture from the starting point region through the substrate, facilitating clean separation without direct mechanical contact that would cause damage.
2Manufacturing precision
If laser cutting is used to divide the substrate, then chipping and cracking are reduced, but the cutting speed and efficiency are insufficient
Solution Approach 1:
The cutting process is segmented into two distinct stages: first, a laser cut creates a starting point region and initiates a fracture; second, a mechanical saw completes the division. This segmentation allows each method to perform its optimal function - laser for precision and stress reduction, mechanical saw for speed and completion.
Solution Approach 2:
The invention merges laser cutting technology with mechanical sawing in a sequential hybrid process. The laser cut prepares the substrate by creating a controlled fracture path, and the mechanical saw follows to complete the division, combining the advantages of both methods to achieve high speed and high quality simultaneously.
3Productivity
If the saw cuts through the entire substrate, then complete division is achieved, but the risk of chipping and cracking increases
Solution Approach 1:
The laser cut performs a preliminary action by creating a starting point region and initiating a fracture that propagates through the substrate thickness. This pre-fracture reduces the mechanical stress required during sawing, enabling complete division while maintaining structural integrity and preventing chipping and cracking.
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 approach allows for smooth cutting faces, reduces the risk of chipping and cracking, and enables higher sawing speeds compared to conventional methods, particularly effective for thicker wafers.
Implementation Method 1
applying a laser cut to the substrate
Implementation Method 2
irradiation with laser light, which generates a starting point region for cutting within the wafer
Implementation Method 3
By attaching an expansion film to the rear face and expanding the film, a fracture is generated from the starting point region to the front and rear surfaces of the wafer
Data Source
AI summary
The method comprises providing a substrate like a semiconductor wafer (1), applying a laser cut (4) of the substrate, and subsequently applying a saw to divide the substrate from a main surface (10). The laser cut (4) may be used to cut along boundaries of saw streets (7).