Wafer Transfer via UV-Reduced Tape Adhesion
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Solution Overview
Problem
Existing wafer transferring methods often damage the wafer during the process of switching from one tape to another, particularly when cutting the tape along the outer diameter.
Innovation Solution
A method involving a second tape pressure-bonded to a second frame with a smaller outer diameter than the first frame, followed by cutting the first tape along the outer periphery of the second frame, reducing the pressure-bonding force using ultraviolet rays, and peeling the first tape off the wafer, allowing for safe transfer without damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tape is cut along the outer diameter of the wafer to transfer it from one tape to another, then the wafer can be transferred, but the wafer may be damaged
Solution Approach 1:
The patent applies preliminary action by reducing the pressure-bonding force of the first tape before cutting it. This is achieved by heating the first tape to a temperature below its glass transition temperature, which decreases the adhesive strength. By performing this softening step before cutting, the tape can be separated without damaging the wafer, thus resolving the contradiction between wafer integrity and ease of manufacture
Solution Approach 2:
The patent changes the temperature parameter of the first tape from room temperature to a elevated temperature (below glass transition temperature). This parameter change reduces the pressure-bonding force of the tape, allowing it to be cut and removed without damaging the wafer. This resolves the technical contradiction by modifying the physical state of the tape to enable safe cutting
2Reliability
If a second tape with smaller outer diameter is used, then the wafer can be transferred safely, but the pressure-bonding force of the first tape must be reduced
Solution Approach 1:
The patent changes the temperature parameter of the first tape to reduce its pressure-bonding force. By heating the tape to a temperature below its glass transition temperature, the adhesive properties are modified, allowing the tape to be easily removed after the second tape is in place. This resolves the contradiction by using parameter change to control the bonding force
Solution Approach 2:
The patent employs periodic action through a multi-step process: first bonding the wafer to the first tape, then introducing the second tape, heating to reduce bonding force, cutting the first tape, and finally removing it. This sequential periodic process allows safe wafer transfer while managing the pressure-bonding force at appropriate stages
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
Enables the transfer of a wafer from one tape to another without damaging it, ensuring the wafer's integrity for subsequent processing steps.
Implementation Method 1
the first tape is an ultraviolet (UV) curing type tape, and the pressure-bonding force lowering is carried out by applying ultraviolet rays to the first tape
Data Source
AI summary
A wafer is positioned in an opening of a first frame. The wafer is pressure-bonded at one surface thereof to a first tape together with the first frame, onto a second tape pressure-bonded to a second frame. The wafer is processed by pressure-bonding the second tape, which is pressure-bonded to the second frame having an outer diameter smaller than an inner diameter of the opening of the first frame, to another surface of the wafer, cutting the first tape along an outer periphery of the second frame, imparting an external stimulus to the first tape to lower a pressure-bonding force with which the first tape is pressure-bonded to the one surface of the wafer, and peeling off the first tape from the one surface of the wafer pressure-bonded to the second tape.