IC Package Lid Retention for Thermal Interface Metal Reflow
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Solution Overview
Problem
The semiconductor industry faces challenges in packaging integrated circuit dies due to issues with heat dissipation, where metal overflow during the heat clamp or reflow process can lead to shorting of components and voids in the heat dissipation structure, affecting the reliability and performance of integrated circuit packages.
Innovation Solution
A retaining structure is formed on the package substrate adjacent to the heat dissipation structure, which contains any subsequent bleeding or reflow of metal, such as indium, during the heat clamp or reflow process, preventing overflow and void formation by physically contacting the lid and underfill, thereby enhancing package reliability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heat clamp or reflow process is performed to attach lid and heat dissipation structure, then bonding strength is improved, but metal overflow and voids occur causing shorting and reliability issues
Solution Approach 1:
A retaining structure is formed on the package substrate before the heat clamp or reflow process. This retaining structure pre-establishes physical barriers that contain the metal material within the heat dissipation structure during subsequent heating processes, preventing metal overflow that would cause shorting while allowing the bonding process to proceed effectively
2Temperature
If heat dissipation structure is attached during heat clamp process, then thermal management is improved, but metal bleeding causes shorting of package components
Solution Approach 1:
The retaining structure is formed in advance on the package substrate, creating containment barriers before the heat clamp process begins. These barriers prevent metal material from bleeding out of the heat dissipation structure during the high-temperature bonding process, eliminating the harmful shorting effect while maintaining effective heat dissipation
3Reliability
If reflow process is used to bond thermal interface material, then bonding reliability is improved, but metal reflow creates voids in heat dissipation structure
Solution Approach 1:
The retaining structure is pre-formed on the package substrate to establish containment boundaries. During the reflow process, these boundaries restrict metal material movement, preventing void formation within the heat dissipation structure while still allowing sufficient metal flow to achieve reliable bonding of the thermal interface material
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 retaining structure effectively prevents metal overflow and voids in the heat dissipation structure, improving the reliability and performance of integrated circuit packages by containing the metal reflow, thus ensuring reliable electrical connections and thermal pathways.
Implementation Method 1
performing a bonding process to bond the thermal interface material to the back-side metal layer and the lid, the bonding process being performed at a temperature greater than the melting point of the thermal interface material
Data Source
AI summary
An embodiment is a device including a package component including an integrated circuit die and conductive connectors connected to the integrated circuit die, the conductive connectors disposed at a first side of the package component. The device also includes a metal layer on a second side of the package component, the second side being opposite the first side. The device also includes a thermal interface material on the metal layer. The device also includes a lid on the thermal interface material. The device also includes a retaining structure on sidewalls of the package component and the thermal interface material. The device also includes a package substrate connected to the conductive connectors, the lid being adhered to the package substrate.