Semiconductor Package Lid Interface Using Intermetallic TIM
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Solution Overview
Problem
The challenge in semiconductor packaging is the formation of voids between semiconductor dies and lids during reflow processes, which affects heat transfer efficiency and package performance and reliability.
Innovation Solution
A composite metal feature comprising intermetallic compounds is formed by reacting a metal feature with a melted thermal interface material (TIM) layer, converting it to improve heat transfer efficiency by preventing void formation during reflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a thermal interface material (TIM) layer is used between semiconductor dies and lid, then heat transfer efficiency is improved, but voids form during reflow process which reduces reliability
Solution Approach 1:
The patent changes the physical and chemical parameters of the TIM layer by converting it into an intermetallic compound through controlled reaction with a metal feature during reflow. This parameter transformation eliminates void formation while preserving thermal conductivity, as the intermetallic compound has superior bonding characteristics and no voids compared to the original TIM material.
Solution Approach 2:
The patent utilizes phase transition during the reflow process where the TIM layer undergoes chemical transformation into an intermetallic compound. This phase change occurs at controlled temperatures during reflow, converting the TIM from its original state to a more stable intermetallic state that prevents void formation and ensures reliable bonding between the semiconductor die and lid.
2Ease of manufacture
If reflow process is performed to attach lid to substrate, then package assembly is completed, but voids form between semiconductor dies and lid reducing heat transfer
Solution Approach 1:
The patent applies preliminary action by pre-positioning a metal feature adjacent to the TIM layer before the reflow process. This metal feature is strategically placed to react with the TIM during reflow, converting it to an intermetallic compound that prevents void formation. The preliminary placement of this reactive metal feature ensures that when reflow occurs, the TIM is already positioned to undergo the beneficial transformation.
Solution Approach 2:
The patent introduces a metal feature as an intermediary substance that mediates the bonding process between the semiconductor die and lid. This intermediary metal feature reacts with the TIM layer during reflow to form an intermetallic compound, which acts as a superior bonding interface that eliminates voids while maintaining thermal conductivity. The intermediary transformation converts a potentially problematic TIM layer into a beneficial bonding 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 method enhances heat transfer efficiency and improves the performance and reliability of semiconductor packages by reducing the risk of voids between semiconductor dies and lids.
Implementation Method 1
a first metal feature and a second metal feature react to generate a third metal feature
Implementation Method 2
improve heat transfer efficiency by preventing void formation during reflow
Data Source
AI summary
A semiconductor package and the method of forming the same are provided. The semiconductor package may include a substrate, a semiconductor package component having a semiconductor die bonded to the substrate, a lid attached to the substrate, and a first composite metal feature between the semiconductor package component and the lid. The first composite metal feature may include a first metal feature having a first material and a second metal feature having a second material. The first material may be an intermetallic compound. The second material may be different from the first material.