Lid Engineered Features Enhance Adhesion and Heat Transfer
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Solution Overview
Problem
Conventional chip package assemblies experience delamination of the lid from the IC die due to thermal expansion, leading to reduced adhesion and altered heat transfer rates, affecting device performance and reliability.
Innovation Solution
The introduction of engineered features on the lid's surface, such as recesses or protrusions, enhances adhesion by increasing the surface area contact with the adhesive, thereby improving the mechanical interlock and heat transfer between the lid and the IC die.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lid is heated during installation and operation, then the lid can be mounted and functions to protect the die, but thermal expansion causes the lid to deform and delaminate from the die
Solution Approach 1:
The lid is designed with non-uniform thickness, having a first thickness in a first region and a second thickness in a second region. This local variation in geometry compensates for thermal expansion effects, maintaining lid planarity and adhesion to the die during temperature changes
Solution Approach 2:
The lid's physical parameters (thickness distribution) are specifically engineered to change in response to thermal conditions. The varying thickness profile allows the lid to accommodate thermal expansion while maintaining stable adhesion and planarity across different operating temperatures
2Strength
If the lid is made thicker to improve strength and protection, then the die is better protected, but the lid becomes more prone to delamination due to increased thermal stress
Solution Approach 1:
Rather than uniformly increasing thickness, the lid employs localized thickness variations - thicker in regions requiring protection and structural integrity, thinner in regions where thermal stress accumulation would cause delamination. This selective thickening maintains both strength and adhesion
3Ease of manufacture
If conventional adhesive bonding is used to attach the lid to the die, then the process is simple, but the adhesion is insufficient under thermal cycling conditions
Solution Approach 1:
The adhesive bonding parameters are optimized for the specific thermal cycling conditions. The adhesive layer thickness, composition, and curing parameters are specifically tuned to maintain strong adhesion while accommodating thermal expansion differences between the lid and die
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
The enhanced adhesion reduces the likelihood of lid delamination, maintains consistent heat transfer, and improves device performance across a wider range of operating conditions with reduced manufacturing complexity and cost.
Implementation Method 1
The engineered features have a geometry selected to enhance adhesion of the lid to the IC die
Implementation Method 2
the delamination of the lid from the die changes the rate of heat transfer between the die and lid
Data Source
AI summary
A method and apparatus are provided which improve the adhesion of a lid to an IC die of an IC (chip) package. In one embodiment, a chip package assembly is provided that includes an IC die, a package substrate and a lid. The IC die is coupled to the package substrate. The lid has a first surface and a second surface. The second surface of the lid faces away from the first surface and towards the IC die. The second surface of the lid has a plurality of engineered features. The adhesive couples the plurality of engineered features of the lid to the IC die.