Wafer Dicing with Hardened Protection Sheet
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Solution Overview
Problem
Existing methods for dicing thin silicon wafers face challenges such as chipping, internal stress, and reduced yield due to the brittleness and fragility of thin wafers, especially when the thickness is less than 0.1 mm, leading to instability during the dicing process and potential damage from grindstones or laser heat.
Innovation Solution
A method involving the application of a protection sheet with a Vickers hardness of 2 or more, formed using thermosetting or ultraviolet curing resin, is applied to the wafer to increase its rigidity and stability during dicing, allowing for stable advancement of the grindstone along dicing lines, and using a grindstone with processed abrasive grains to reduce chipping and enhance dicing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a thin wafer (thickness less than 0.1 mm) is diced directly without additional support, then the dicing process can be simpler and faster, but the wafer is prone to chipping, internal stress, and instability during dicing
Solution Approach 1:
A protection sheet with Vickers hardness of 2 or more is introduced as an intermediary layer between the grindstone and the thin wafer. This protection sheet provides mechanical support to the wafer during dicing, preventing chipping and instability while allowing high-speed dicing to proceed. The protection sheet acts as a mediator that transfers the cutting force from the grindstone to the wafer in a controlled manner.
2Manufacturing precision
If a protection sheet with high hardness (Vickers hardness of 2 or more) is applied to the wafer, then chipping is reduced and dicing stability is improved, but the process complexity increases due to additional preparation steps
Solution Approach 1:
The protection sheet's hardness parameter (Vickers hardness of 2 or more) is specifically controlled to provide optimal protection. This parameter change ensures the sheet is hard enough to prevent chipping during high-speed dicing but not so hard that it causes excessive wear to the grindstone or makes removal difficult. The hardness parameter is the key physical property that balances protection effectiveness with process simplicity.
3Productivity
If a grindstone with processed abrasive grains is used, then chipping is reduced and dicing efficiency is enhanced, but the cost and complexity of grindstone preparation increases
Solution Approach 1:
The abrasive grains on the grindstone are processed in advance before actual dicing operations. This preliminary processing creates optimally shaped abrasive grains that reduce chipping during dicing. By performing this preparation beforehand, the actual dicing process can proceed at high speed without interruption, and the grindstone can be reused multiple times with consistent performance.
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 significantly reduces chipping and improves the yield and productivity of dicing thin wafers, enabling high-speed dicing with reduced damage to the chips and economic advantages by avoiding the need for expensive laser devices.
Implementation Method 1
forming a protection sheet tightly on one side of the wafer, the protection sheet having a Vickers hardness of 2 or more
Implementation Method 2
dicing the wafer by a grindstone, the wafer having the protection sheet thereon
Data Source
AI summary
The method for dicing a wafer including the steps of: reducing a thickness of a wafer to at least 0.1mm or less; forming a protection sheet tightly on one side of the wafer, the protection sheet having a Vickers hardness of 2 or more; and dicing the wafer by a grindstone, the wafer having the protection sheet thereon.