Wafer-Level Die Transfer Using Adhesive Tape and Roller Contact
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Solution Overview
Problem
Existing die-transfer tools and methods are inefficient and prone to die damage during the transfer process, particularly when handling multiple dies simultaneously, as they often rely on pick-and-place techniques that are slow and can cause stress on the semiconductor wafers.
Innovation Solution
A die-transfer tool and method utilizing a source frame stage and a target frame stage with a second tape of higher adhesive strength, where the dies are transferred from a first tape to a second tape using a roller to ensure all dies are transferred simultaneously, reducing stress and damage by using a double-sided sawing process and a pre-debonding process to enhance adhesive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pick-and-place tools are used to transfer dies, then individual die transfer is achieved, but transfer speed is slow and die damage occurs
Solution Approach 1:
The patent merges multiple individual die transfer operations into a single wafer-level transfer operation. The entire wafer is transferred simultaneously from the source frame to the target frame in one action, rather than picking and placing each die individually. This combining of operations dramatically increases transfer speed while eliminating the repeated mechanical stress that causes die damage in traditional pick-and-place methods.
Solution Approach 2:
The patent segments the transfer process into distinct phases: (1) wafer-level simultaneous transfer using adhesive tapes, and (2) subsequent individual die separation at the target location. This segmentation allows the high-speed wafer transfer to occur without the mechanical stress of individual die handling, while still achieving individual die placement eventually. The stress of separation is applied after transfer, not during the critical transfer phase.
2Productivity
If traditional die transfer methods are used, then individual die handling is achieved, but transfer efficiency is low
Solution Approach 1:
The patent enables continuous wafer-level transfer by maintaining adhesive contact between the wafer and transfer tape throughout the transfer process. The entire wafer is transferred in one continuous motion without stopping to handle individual dies, eliminating the time losses associated with sequential pick-and-place operations. The adhesive mechanism allows the transfer to proceed continuously at high speed.
Solution Approach 2:
Multiple die transfer operations are merged into a single wafer-level transfer action. Instead of performing N individual die transfers for N dies on a wafer, the system performs one collective transfer operation that moves all dies simultaneously, dramatically improving transfer efficiency and reducing total transfer time.
3Reliability
If adhesive strength is increased to prevent die detachment, then transfer reliability improves, but die damage from stress increases
Solution Approach 1:
The patent segments the adhesive interaction into two distinct phases: (1) strong adhesive bonding during the transfer phase to prevent die detachment, and (2) controlled adhesive release at the target location using heat or solvent. This segmentation allows the adhesive to provide strong holding force during transfer without causing permanent damage, as the adhesive bond is designed to be reversible under specific release conditions.
Solution Approach 2:
The patent changes the physical or chemical parameters of the adhesive system to control its strength characteristics. By adjusting adhesive composition, temperature, or other parameters, the system achieves optimal adhesion during transfer while ensuring gentle, controllable release at the destination. Parameter changes allow the adhesive to provide strong bonding when needed and easy release when needed, without causing die damage.
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
The method enables efficient, simultaneous transfer of wafer-level dies with reduced damage, improving yield and efficiency compared to traditional pick-and-place tools by using a double-sided sawing process and pre-debonding to minimize stress and collisions during the transfer.
Implementation Method 1
The second tape has greater adhesive strength than the first tape
Data Source
AI summary
A die-transfer tool includes a source frame stage, a target frame stage, a roller, and a driving mechanism. The source frame stage is configured to secure a first tape. The target frame stage is configured to secure a second tape, wherein the second tape has an adhesive surface facing the source frame stage when the second tape is mounted on the target frame stage. The roller is configured to move laterally over the non-adhesive surface of the second tape opposite the adhesive surface when a plurality of dies is between the first tape and the adhesive surface of the second tape. The driving mechanism is configured to vertically drive the target frame stage to adjust the relative position of the target frame stage above the source frame stage.