Thin Subject Assisted Debonding of Semiconductor Wafers
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Solution Overview
Problem
Current mechanical and laser debonding methods for semiconductor wafers in semiconductor packaging face challenges such as high stress leading to device damage, incomplete debonding, and residual adhesive issues, making them unreliable for high-volume production.
Innovation Solution
The introduction of a thin subject that applies a wedging or shear force to the adhesive layer during debonding, either in conjunction with mechanical peeling or after laser ablation, to facilitate uniform separation and remove residual adhesives, using a blade or wire with specific cross-sectional profiles in a reciprocating saw motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical debonding is used to separate the adhesive bonded carrier-workpiece pair, then the debonding process can be performed without additional equipment, but high stress is applied to the adhesive and device wafer causing localized device wafer damage
Solution Approach 1:
A thin subject (intermediary tool) is introduced between the peeling device and the adhesive bonded pair. This thin subject acts as a mediator that distributes the mechanical stress uniformly across the debonding interface, preventing localized high stress concentrations that would damage the device wafer, while still enabling mechanical debonding to proceed
2Measurement precision
If laser debonding is used to separate the adhesive bonded carrier-workpiece pair, then the debonding process can be performed with high precision, but the laser can damage the adhesive and device wafer due to misfocus or nonuniformity in the release layer
Solution Approach 1:
The thin subject serves as an intermediary that protects the adhesive and device wafer from direct laser exposure. It allows the laser to ablate the release layer with high precision while preventing laser energy from concentrating and damaging the underlying adhesive and wafer structures
3Productivity
If conventional debonding methods are used, then the process can be completed with standard equipment, but residual adhesive remains and results in incomplete debonding or thinned wafer damage
Solution Approach 1:
The thin subject acts as an intermediary tool that mechanically scrapes or wipes the debonding interface during or after separation. This ensures complete removal of residual adhesive from both the carrier and workpiece surfaces, achieving thorough debonding without damaging the thinned wafer
Solution Approach 2:
The patent replaces conventional mechanical peeling with a hybrid approach that combines controlled laser ablation of the release layer with mechanical action of the thin subject to remove adhesives, substituting pure mechanical stress with a more sophisticated mechanism that achieves cleaner separation
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 enhances debonding efficiency, reduces defects, and eliminates residual adhesive issues, improving throughput and reliability in semiconductor wafer processing.
Implementation Method 1
The introduction of a thin subject that applies a wedging or shear force to the adhesive layer during debonding
Implementation Method 2
actuating an external device into direct physical contact with the adhesive layer without the use of any additional mechanical or electromagnetic forces
Implementation Method 3
using a blade or wire with specific cross-sectional profiles in a reciprocating saw motion
Data Source
AI summary
Disclosed is a thin subject assisted debonding method for separating temporarily bonded workpiece-carrier pair. The thin subject can be a thin wire, or thin filament, or thin blade. The thin subject can be applied between the workpiece and carrier pair in association with laser debonding or mechanical debonding to provide well controlled and targeted wedging function to the delaminating temporary adhesive and its adjacent substrate to which it is separating from. The workpiece can be a semiconductor wafer that has been thinned and processed, and the carrier can be a semiconductor non-device wafer or any other rigid substrate such as a glass wafer or panel. The application of a thin subject between the workpiece and carrier during debonding provides the advantage of high throughput and low defect rate.