Flexible Substrate Assembly Adhesive CTE Mismatch
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Solution Overview
Problem
Flexible substrates experience significant distortion due to thermal expansion mismatch when coupled with carrier substrates during processing, leading to handling errors and defects in electronic circuits.
Innovation Solution
A method involving a cross-linking adhesive is used to couple a flexible substrate to a carrier substrate, with the adhesive being configured to outgas at a controlled rate and applied in a specific thickness to minimize distortion, and the substrates are laminated together with a protective template to stabilize the assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a flexible substrate is temporarily mounted to a carrier substrate during processing, then the flexible substrate can be moved through process steps, but significant distortion occurs due to CTE mismatch
Solution Approach 1:
A specialized adhesive layer is introduced as an intermediary between the flexible substrate and carrier substrate. This adhesive has a coefficient of thermal expansion specifically matched to bridge the CTE mismatch between the flexible substrate and carrier, thereby mediating the thermal expansion differences and reducing distortion during temperature excursions
Solution Approach 2:
The coefficient of thermal expansion of the adhesive layer is specifically selected and controlled to match that of the flexible substrate. By changing and optimizing this physical parameter of the adhesive, the system compensates for the CTE mismatch between components, reducing thermal distortion during processing
2Strength
If a typical adhesive is used to couple flexible substrate to carrier substrate, then the substrates can be bonded, but significant distortion and handling errors occur
Solution Approach 1:
The adhesive's coefficient of thermal expansion is specifically selected to match the flexible substrate, and the adhesive layer thickness is controlled within a specific range (0.5-5 micrometers). By optimizing these parameters, the adhesive provides both strong bonding and minimal distortion, eliminating handling errors and defects
Solution Approach 2:
The system uses a composite structure consisting of the flexible substrate, a specifically formulated adhesive layer with matched CTE, and the carrier substrate. This composite approach combines materials with different properties to achieve both strong bonding and minimal thermal distortion
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 effectively reduces distortion and handling errors, enabling the fabrication of semiconductor devices with minimal defects and improved alignment accuracy.
Implementation Method 1
the adhesive being configured to outgas at a controlled rate
Implementation Method 2
coupling the carrier substrate to the flexible substrate using the cross-linking adhesive
Implementation Method 3
the substrates are laminated together with a protective template to stabilize the assembly
Data Source
AI summary
Some embodiments include a method of preparing a flexible substrate assembly. Other embodiments of related methods and structures are also disclosed.