Metal TIM Package Structure to Reduce Thermal Cycling Delamination
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Solution Overview
Problem
Existing semiconductor device packaging structures face challenges in heat dissipation and reliability due to stress on metal thermal interface materials (TIM) during thermal cycling, leading to potential delamination and reduced package reliability.
Innovation Solution
A novel metal lid attachment approach using a thermal compression bonding process with a metal TIM, where heat and pressure are applied to change the thickness and lateral sidewall shape of the TIM, reducing stress and the risk of delamination, and allowing direct bonding of the metal lid to the semiconductor device without an adhesive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metal thermal interface material (TIM) is used to bond the metal lid to the semiconductor device, then heat dissipation is improved, but stress during thermal cycling causes delamination and reduces reliability
Solution Approach 1:
The patent divides the TIM into multiple layers: a first TIM layer with a first thermal conductivity and a second TIM layer with a second thermal conductivity. This segmentation allows each layer to handle different thermal and mechanical stresses, improving overall heat dissipation while reducing delamination risk during thermal cycling.
Solution Approach 2:
The patent uses composite TIM structure combining different materials with distinct thermal conductivities. The first TIM layer (higher thermal conductivity) optimizes heat transfer, while the second TIM layer (lower thermal conductivity) provides mechanical compliance and stress relief, creating a composite solution that balances thermal performance and reliability.
2Strength
If adhesive layer is used to attach metal lid to package substrate, then bonding is achieved, but device complexity and manufacturing steps increase
Solution Approach 1:
The patent merges the bonding function into the TIM itself. The TIM layers serve dual purposes: thermal management (heat dissipation) and mechanical bonding (attaching metal lid to semiconductor device). This eliminates the need for separate adhesive layers, reducing package complexity and manufacturing steps while maintaining bonding strength.
Solution Approach 2:
The TIM is designed to perform multiple functions simultaneously: it provides thermal conduction for heat dissipation, mechanical bonding between components, and stress relief during thermal cycling. This multi-functionality replaces what would traditionally require separate adhesive and thermal interface materials, simplifying the overall package structure.
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 the reliability of the semiconductor device package by improving heat dissipation and reducing the risk of TIM delamination, thereby increasing the package's overall reliability and potentially lowering costs by omitting the need for an adhesive layer.
Implementation Method 1
a metal thermal interface material (TIM) interposed between the metal lid and the semiconductor device
Implementation Method 2
A novel metal lid attachment approach using a thermal compression bonding process with a metal TIM, where heat and pressure are applied to change the thickness and lateral sidewall shape of the TIM
Data Source
AI summary
A semiconductor device package is provided, including a package substrate, a semiconductor device, a metal lid, and a metal thermal interface material (TIM). The package substrate has a first surface. The semiconductor device is disposed over the first surface of the package substrate. The metal lid is disposed over the semiconductor device and the package substrate. The metal TIM is interposed between the metal lid and the top surface of the semiconductor device for bonding the metal lid and the semiconductor device. A shape of the lateral sidewall of the metal TIM in a longitudinal section is concave arc, and the outermost point of the lateral sidewall is within the boundary of the semiconductor device.