Reversible Thermocompression Bonding With Gas-Actuated Debonding
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Solution Overview
Problem
Current thermocompression bonding methods for three-dimensional integration in computing systems risk damaging chips due to high heat required for debonding, which can cause thermal damage.
Innovation Solution
A reversable attachment system with a gas-permeable layer and extension actuator that allows for debonding at lower temperatures by absorbing gas, enabling reversible thermocompression bonding without melting the bond metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermocompression bonding is used to achieve strong inter-chip connections, then bond strength is improved, but chip damage risk increases due to high heat required for debonding
Solution Approach 1:
The bonding structure is segmented into multiple functional layers: a first bond layer for initial bonding, a gas-permeable layer for controlled gas transmission, and a second bond layer for final bonding. This segmentation allows the gas-permeable layer to expand independently when exposed to gas, creating fractures that enable debonding without requiring high heat that would damage the chips.
Solution Approach 2:
The invention changes the physical-chemical parameters of the bonding system by introducing a gas-permeable layer that undergoes parameter change when exposed to gas. The layer absorbs gas and expands, changing its volume and creating mechanical stress that fractures the bond. This parameter change enables debonding at lower temperatures, avoiding chip damage from high heat.
2Ease of repair
If high heat is applied to melt gold and debond chips, then debonding capability is improved, but thermal damage to chips increases
Solution Approach 1:
The invention replaces the thermal field (heat-based debonding) with a mechanical field (gas-induced expansion and fracture). Instead of using high heat to melt gold and debond chips, the gas-permeable layer absorbs gas and expands mechanically, creating fractures that enable debonding. This substitution eliminates the need for high-temperature processing during debonding, preventing thermal damage to the chips.
Solution Approach 2:
The gas-permeable layer undergoes a phase transition when exposed to gas, absorbing the gas and expanding in volume. This phase change from a compact state to an expanded state creates the mechanical force needed to fracture the bond and enable debonding, providing a non-thermal mechanism for achieving ease of repair without thermal damage.
3Ease of manufacture
If conventional thermocompression bonding is used, then manufacturing simplicity is maintained, but reworkability is lost due to permanent bonding
Solution Approach 1:
The bonding system transitions from a static permanent bond to a dynamic reversible bond. The gas-permeable layer can be exposed to gas to expand and create fractures for debonding, then the gas can be removed and the layer returns to its original state, allowing the bonding process to be repeated. This dynamic behavior enables reworkability while maintaining manufacturing simplicity, as the same basic thermocompression bonding process can be applied multiple times.
Solution Approach 2:
The gas-permeable layer is temporarily modified by gas absorption to enable debonding, then the gas is removed and the layer recovers its original state. This discarding of the gas (temporary modification) and recovery of the layer (restoration) allows the bonding interface to be reset for rework, providing adaptability and versatility without complicating the manufacturing process.
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 reversible attachment and detachment of substrates without high heat, preserving chip integrity and facilitating reworkable inter-substrate connections.
Implementation Method 1
The extension actuator is configured to expand in response to an absorption of a gas
Implementation Method 2
The outer gas-permeable layer is configured to expand and create a fracture in the inter-substrate bond structure in response to another absorption of the gas
Implementation Method 3
The inter-substrate bond structure is configured to form an initial thermocompression bond with the mating layer in response to an applied pressure and an applied heat
Data Source
AI summary
A reversable attachment system includes an adhesion layer, an inter-substrate bond structure, a mating layer and an extension actuator. The adhesion layer is configured to attach to a first substrate. The inter-substrate bond structure is coupled to the adhesion layer. The mating layer is configured to attach to a second substrate. The extension actuator is configured to attach to the second substrate and expand in response to an absorption of a gas. The inter-substrate bond structure is configured to form an initial thermocompression bond with the mating layer in response to an applied pressure and an applied heat. The expansion of the extension actuator in response to absorbing the gas detaches the inter-substrate bond structure from the mating layer.