Substrate Debonding by Solvent-Swollen Adhesive Bending
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for debonding thermocompression-bonded chips, especially at fine-pitch spacings, risk damaging the chips due to the high heat required to melt gold and break bonds, and lack efficient mechanisms for selective detachment in three-dimensional integrated systems.
Innovation Solution
A method involving the application of an adhesive layer to a substrate, which swells upon solvent absorption, causing localized stress concentrations and bending that breaks thermocompression bonds between substrates, allowing for selective debonding without heat, using a handle and solvent like acetone to induce radial swelling and row-by-row bond disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high heat is applied to melt gold and break thermocompression bonds, then bond breaking is achieved, but chip damage risk increases significantly
Solution Approach 1:
The patent replaces the thermal field (heat) with a mechanical field (bending force) to achieve bond breaking. By applying bending force to the substrate, the thermocompression bonds are mechanically disrupted without requiring high temperatures, thus avoiding thermal damage to the chip while achieving the desired debonding effect.
Solution Approach 2:
The patent changes the physical parameter used for bond breaking from temperature (thermal parameter) to mechanical stress (mechanical parameter). Instead of increasing temperature to melt the bonding material, the method applies controlled bending stress to mechanically break the bonds, fundamentally changing the operating parameter from thermal to mechanical domain.
2Force
If direct pulling force is applied to debond chips, then separation is achieved, but debonding forces are excessively high causing damage
Solution Approach 1:
The patent applies bending force locally at specific regions of the substrate rather than applying uniform pulling force across the entire bonded area. This localized mechanical action concentrates the stress at the bond interface, enabling effective debonding with much lower overall forces compared to direct pulling methods.
Solution Approach 2:
Instead of applying force in the vertical direction (direct pulling perpendicular to the bond interface), the patent applies force in the lateral dimension by bending the substrate. This dimensional change transforms the debonding mechanism from direct tensile separation to bending-induced interface disruption, significantly reducing the required force magnitude.
3Stability of the object's composition
If uniform debonding force is applied across the bonded area, then complete separation is achieved, but stress distribution is inefficient and forces are high
Solution Approach 1:
The patent segments the debonding process by creating multiple localized stress concentration points along the bond interface through bending. Rather than applying a single uniform force, the bending action generates distributed stress concentrations at different locations, enabling progressive and efficient bond breaking across the entire interface with reduced overall force requirements.
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 enables low-force, low-risk debonding of thermocompression-bonded chips, minimizing chip damage and allowing for reworkable processes, with localized stress distributions effectively unzipping bond interfaces, reducing debonding forces by approximately 100 times compared to direct pulling methods.
Implementation Method 1
absorbing a solvent into the adhesive layer
Implementation Method 2
swelling the adhesive layer in response to the absorbing of the solvent
Implementation Method 3
the swelling includes moving the swelling of the adhesive layer radially inward over time as the solvent is absorbed further into the adhesive layer
Implementation Method 4
The breaking includes generating a plurality of localized stress concentrations at the plurality of thermocompression bonds in response to the bending
Data Source
AI summary
A method for debonding a bonded part includes attaching a handle to a third side of a first substrate of the bonded part with an adhesive layer. The bonded part has a plurality of inter-substrate bond structures that couple a first side of the first substrate to a second side of a second substrate. The third side of the first substrate is opposite the first side. The first substrate and the second substrate have different thicknesses. The method includes absorbing a solvent into the adhesive layer, swelling the adhesive layer in response to the absorbing of the solvent, bending the first substrate in response to the swelling, and breaking a plurality of thermocompression bonds between the plurality of inter-substrate bond structures and the second side of the second substrate in response to the bending to debond the first substrate.