Wafer Dicing Before Grinding for Thin Die Integrity
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Solution Overview
Problem
Existing methods for fabricating semiconductor articles face challenges in reducing wafer thickness without causing chip breakage and cracking during dicing, and lack a method to remove adhesive sheets from wafers without peeling them off.
Innovation Solution
The method involves dicing the wafer before grinding and using a combination of thermal tape, UV tape, and dicing tape to separate wafer dies from a carrier by applying adequate pressure and heat to the adhesive sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the wafer thickness is reduced to 50-100 μm or less by grinding, then the integrated circuit package thickness is reduced, but chip breakage and cracking occur during dicing
Solution Approach 1:
The patent applies preliminary dicing before grinding to reduce wafer thickness. By performing the dicing operation first when the wafer still has sufficient thickness (around 350 μm), the structural integrity is maintained during cutting. Subsequently, the wafer is ground down to the target thickness of 50-100 μm, eliminating the risk of breakage that would occur if dicing were performed on already-thinned wafers.
Solution Approach 2:
The patent inverts the conventional sequence of operations by performing dicing before grinding instead of grinding before dicing. This reversal of the process order allows the wafer to maintain its mechanical strength during the dicing operation, while still achieving the desired thin final thickness through the subsequent grinding step.
2Ease of manufacture
If adhesive sheets are peeled from the wafer surface, then the wafer can be processed, but mechanical damage and contamination occur
Solution Approach 1:
The patent utilizes thermal phase transition to remove adhesive sheets. By heating the adhesive layer to its transition temperature, the adhesive properties change, allowing the sheet to be released from the wafer surface without mechanical peeling. This thermal approach eliminates the mechanical stresses and contamination risks associated with traditional peeling methods.
Solution Approach 2:
The patent replaces the mechanical peeling process with a thermal release mechanism. Instead of applying mechanical force to peel off the adhesive sheet, which causes damage, the system uses controlled heating to induce a phase transition in the adhesive, enabling non-contact or minimal-contact removal that preserves wafer integrity.
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 reduces the risk of backside chipping, improves wafer die strength, and allows for the removal of adhesive sheets without peeling, enhancing the reliability and efficiency of the semiconductor fabrication process.
Implementation Method 1
a heated plate is pressed onto said adhesive sheet thereafter
Implementation Method 2
sticking a surface protective sheet to a circuit surface of a wafer
Data Source
AI summary
The present invention discloses a method for fabricating semiconductor articles comprising the steps of partially cutting a wafer, applying one or more layers of adhesive sheet onto a carrier, transferring the partially cut wafer onto the adhesive sheet on the carrier; grinding a backside of the wafer to a desired thickness to form separated dies, and removing the separated dies from the carrier, wherein the separated dies are removed from the carrier by adhering another layer of adhesive sheet to the backside of the separated dies, in which a heated plate is pressed onto said adhesive sheet thereafter.