Channeled Die Attach Material for Void-Free Transistor Packaging
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Solution Overview
Problem
Silver Sintered die attach materials used in semiconductor packaging often form voids during curing, which inhibit heat transfer and can lead to packaging failures, especially in large area semiconductor dies like MMICs and GaN HEMTs, due to the random outgassing of volatile organics that become trapped under active transistor areas.
Innovation Solution
Incorporating channels in the die attach material that allow gases to escape to the edges before the material hardens, reducing void formation under critical areas and improving adhesion of protective materials by providing a structured path for outgassing and enhancing thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Silver Sintered die attach material is used to attach semiconductor die to support, then strong mechanical bond and high thermal conductivity are achieved, but voids form during curing that inhibit heat transfer and can lead to packaging failures
Solution Approach 1:
The die attach material is designed with a porous structure containing channels that allow volatile organics to escape during curing. This porous structure prevents void formation while maintaining the material's mechanical bond strength and thermal conductivity properties.
Solution Approach 2:
The invention extracts or removes the harmful byproduct (volatile organics) from the system by providing escape paths through channels. This prevents the accumulation of gas bubbles that would otherwise form voids and compromise heat transfer reliability.
2Ease of manufacture
If volatile organics are present in die attach material for low cost packaging, then cost is reduced, but gas bubbles are generated during curing that become trapped under active transistor areas
Solution Approach 1:
The invention converts the harmful effect of volatile organics (gas bubble formation) into a beneficial process by designing channels that guide the outgassing. The volatile organics are allowed to escape through controlled paths, preventing random void formation while maintaining the cost advantage of using organic-based die attach materials.
Solution Approach 2:
The channels act as an intermediary structure between the die attach material and the external environment, providing a designated path for volatile organics to escape. This mediator prevents direct interaction between the gas bubbles and the semiconductor die, eliminating the harmful effect while preserving the low-cost material composition.
3Reliability
If channels are incorporated in die attach material to allow gas escape, then void formation is reduced and heat transfer is improved, but material structure becomes more complex
Solution Approach 1:
The die attach material is segmented into regions with channels integrated throughout its structure. This segmentation creates multiple escape paths for volatile organics, ensuring that gas bubbles can exit from various locations rather than becoming trapped, thereby improving heat transfer reliability without requiring a completely new material design.
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 significantly reduces voids under active transistor areas, enhancing heat transfer and robustness of the semiconductor package, eliminating the need for costly screening processes and improving yield, while maintaining low-cost packaging solutions.
Implementation Method 1
During the curing of such die attach materials made of metal particles and volatile organics, such as plastic, polymer or resin, the volatile organics outgas, that is to say they generate gas bubbles that become frozen in the die attach material as it hardens
Implementation Method 2
The die attach material provides a high thermal conductivity path to both dissipate high power through the material and also a strong mechanical bond to the package that the die is attached within
Data Source
AI summary
A package includes a circuit that includes at least one active area and at least one secondary device area, a support configured to support the circuit, and a die attach material. The circuit being mounted on the support using the die attach material and the die attach material including at least one channel configured to allow gases generated during curing of the die attach material to be released from the die attach material.