Chip Package Lid Gutter for Thermal Interface Material Containment
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Solution Overview
Problem
Conventional chip packaging schemes face issues with thermal interface material (TIM) spreading out of the intended area, leading to contamination and potential electrical shorts due to its expansion under compressive stress and high temperatures.
Innovation Solution
A chip package design incorporating a lid with a gutter feature on its bottom surface to manage the spread of TIM, allowing it to be contained within the desired region between the lid and IC die, thereby reducing contamination and shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sufficient amounts of TIM are used to achieve full contact area coverage between the lid and IC die, then thermal contact is improved, but TIM spreads into unintended areas causing contamination and potential electrical shorts
Solution Approach 1:
A lid structure acts as an intermediary between the TIM application area and the surrounding environment. The lid includes a receiving area that intercepts and contains TIM before it can spread to contaminate the socket or PCB components, thus protecting the system while maintaining sufficient TIM for thermal contact
Solution Approach 2:
The patent converts the harmful spreading of TIM into a beneficial containment process. The receiving area on the lid captures TIM that would otherwise be harmful debris, and the adhesive layer then secures this captured TIM in place, transforming the contamination problem into a controlled thermal interface solution
2Temperature
If TIM is allowed to expand under compressive stress and high temperatures, then thermal transfer is maintained, but TIM contacts unintended areas and becomes debris
Solution Approach 1:
The patent captures the TIM expansion that occurs under thermal and compressive stress and redirects it into a beneficial containment process. The receiving area on the lid intercepts the expanding TIM, and the adhesive layer secures it, converting what would be harmful debris into a controlled thermal interface material that maintains heat transfer without contamination
3Object-affected harmful factors
If precise TIM application is required to prevent spreading, then contamination is reduced, but manufacturing complexity and cleanup costs increase
Solution Approach 1:
The lid structure with its receiving area and adhesive layer performs the function of TIM containment automatically during the assembly process. The TIM naturally spreads and is captured by the receiving area, then secured by the adhesive layer without requiring external intervention or precise application techniques, thus simplifying manufacturing while preventing contamination
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 gutter design maintains effective heat transfer while minimizing TIM contact with unintended areas, reducing contamination and electrical risks, and eliminating the need for precise TIM application and costly cleanup procedures.
Implementation Method 1
A thermal interface material (TIM) is often used between the lid and IC die to promote heat transfer therebetween. TIM generally has a heat transfer material having a conductivity of at least about 0.3 W/m·K.
Implementation Method 2
Since TIM can expand out from between the IC die and lid due to compressive stress as well as exposure to high temperatures
Data Source
AI summary
A method and apparatus are provided which manages the movement of thermal interface material (TIM) squeezed out from between a lid and an IC die of an IC (chip) package. In one embodiment, a chip package is provided that includes an IC die mounted on a substrate and covered by a lid. A bottom surface of the lid has a die overlapped region facing a top surface of the IC die. The bottom surface of the lid has a first gutter formed therein. An outer sidewall of the first gutter is formed outward of the first die overlapped region as to receive TIM squeezed out from between a lid and an IC die.