Chip Package Thermal Interface Bonding Without Organic Adhesive
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Solution Overview
Problem
Existing thermal interface materials in electronic component packaging require organic adhesives, which increase production costs, affect heat dissipation performance, and create voids due to residue, leading to reduced reliability.
Innovation Solution
The use of indentation bonding to directly fix thermal interface material onto the chip or heat sink without organic adhesives, ensuring temporary positioning and direct contact for improved heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic adhesive is used to bond thermal interface material to chip or heat sink, then the thermal interface material can be fixed in position, but production cost increases and heat dissipation performance deteriorates due to residue voids
Solution Approach 1:
The patent extracts and eliminates the organic adhesive from the bonding process. Instead of using adhesive to bond the thermal interface material (indium) to the chip or heat sink, the invention relies on direct mechanical contact and pressure through indentation bonding, completely removing the adhesive layer that causes voids and performance degradation.
Solution Approach 2:
The patent uses indentation (depression) as an intermediary mechanism to enable bonding. By creating indentations on the surface of the chip or heat sink and pressing the thermal interface material into these indentations, the bonding is achieved through mechanical interlocking rather than chemical adhesion, eliminating the need for organic adhesive.
2Reliability
If organic adhesive is used to bond thermal interface material, then temporary positioning is achieved, but voids form due to residue reducing reliability
Solution Approach 1:
The patent removes the organic adhesive component entirely from the bonding system. By eliminating the adhesive, the source of residue and void formation is completely removed, preventing the harmful effects on reliability while still achieving secure bonding through indentation mechanical interlocking.
Solution Approach 2:
The thermal interface material itself serves the dual function of both bonding agent and thermal interface. The indium material bonds to the chip or heat sink through indentation mechanical interlocking while simultaneously providing the thermal interface function, eliminating the need for separate adhesive layers that create voids.
3Ease of manufacture
If traditional thermal interface material bonding is used, then assembly is achieved, but process complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the positioning and bonding functions into a single indentation bonding step. The indentations are created during chip fabrication, and the same indentation process serves both to position the thermal interface material and to bond it securely, eliminating separate adhesive application and curing steps.
Solution Approach 2:
The indentations are prepared in advance during chip fabrication before the thermal interface material is applied. This preliminary creation of bonding features simplifies the subsequent assembly process, as the bonding interface is already prepared and no additional adhesive application steps are needed.
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
Eliminates the need for organic adhesives, reduces production costs, enhances heat dissipation performance, and increases reliability by preventing void formation.
Implementation Method 1
The main function of thermal interface material is to fill the contact gaps between two materials, to increase the heat dissipation performance of the system, and to effectively reduce the thermal impedance
Implementation Method 2
disposing a thermal interface material onto the chip or the heat sink via indentation bonding
Data Source
AI summary
A package structure includes a substrate, a chip disposed on the substrate and having a backside surface away from the substrate, a heat sink disposed above the substrate and having a surface facing the back side surface, and a thermal interface material disposed between the chip and the heat sink. There is no organic adhesive between the chip and the heat sink. A method for forming the package structure is also provided.