Wafer Dicing Method Using Laser Stealth Processing Before Grinding
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Solution Overview
Problem
In laser stealth dicing of wafers, the need for a high light transmittance dicing tape to reduce laser attenuation leads to increased costs, as the laser must pass through the tape during processing.
Innovation Solution
The method involves performing laser stealth dicing on the back surface of the wafer before grinding and thinning, followed by applying a dicing tape, and then separating the wafer into chips using an expansion process, which allows the laser to directly impact the wafer surface, thereby reducing the need for high light transmittance tape and lowering costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dicing tape is used during laser stealth dicing from the back surface of the wafer, then the wafer is protected during processing, but the laser experiences attenuation requiring expensive high light transmittance tape
Solution Approach 1:
The method performs laser stealth dicing processing on the back surface of the wafer before applying the dicing tape. By reversing the sequence of operations, the laser processing is completed first when the wafer surface is directly accessible, eliminating laser attenuation. The dicing tape is then applied for the subsequent separation process, maintaining its protective function without interfering with laser energy transmission.
2Loss of energy
If high light transmittance dicing tape is used to reduce laser attenuation, then laser processing effectiveness is improved, but the cost of the dicing tape increases
Solution Approach 1:
The invention performs the laser stealth dicing processing before applying the dicing tape. This sequence reversal eliminates the need for expensive high light transmittance tape, as the laser directly processes the wafer back surface without any tape interference. The dicing tape is applied afterward for the mechanical separation process, where its optical properties are irrelevant, thus significantly reducing overall process costs.
3Reliability
If laser stealth dicing is performed from the back surface with dicing tape already applied, then wafer protection is maintained, but the laser must pass through the tape causing energy loss
Solution Approach 1:
The method performs laser stealth dicing processing on the back surface of the wafer before applying the dicing tape. This reverses the traditional sequence, allowing the laser to directly process the wafer surface without passing through the tape. The dicing tape is then applied for the separation process, maintaining wafer protection during handling while eliminating unnecessary laser energy consumption.
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 alleviates laser attenuation and reduces the requirements for expensive high light transmittance dicing tapes, lowering costs while maintaining effective wafer separation.
Implementation Method 1
a first group of laser beams is imposed on a back surface of the wafer along a first dicing path to form a first modified layer
Implementation Method 2
performing laser stealth dicing processing on a wafer from a back surface of the wafer
Implementation Method 3
sticking a dicing tape on the back surface of the wafer after performing the grinding and thinning processing
Implementation Method 4
performing expansion processing on the dicing tape after fixing the wafer on a support platform, where in a process of performing the expansion processing on the dicing tape, the wafer is separated into multiple chips
Data Source
AI summary
This disclosure provides wafer dicing methods, and relates to the field of semiconductor technologies. Implementations of the dicing method may include: performing laser stealth dicing processing on a wafer from a back surface of the wafer; performing grinding and thinning processing on the back surface of the wafer after performing the laser stealth dicing processing; sticking a dicing tape on the back surface of the wafer after performing the grinding and thinning processing; and performing separation processing on the wafer after sticking the dicing tape. In some implementations, stealth dicing (SD) is performed before grinding, so that a laser is directly imposed on a back surface of a wafer, thereby alleviating a laser attenuation problem and lowering requirements on light transmittance of a dicing tape.