Die Attach Channels for Void-Free High-Power Transistor Packaging
Find Innovative SolutionsGenerate Solutions
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 to allow gases generated during curing to escape, reducing the formation of voids under active transistor areas by directing them to the edges of the material before it hardens, thereby improving thermal conductivity and mechanical bonding.
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 applied to the support structure before the semiconductor die is mounted, creating a prepared adhesive layer with controlled geometry. This preliminary application allows the material to be positioned and shaped (including forming channels) before curing, ensuring proper alignment and reducing void formation under the die during subsequent attachment
Solution Approach 2:
The die attach material incorporates channels or void pathways that allow trapped gases to escape during curing. These intentional porous structures prevent gas bubbles from becoming frozen in the material, eliminating voids that would otherwise inhibit heat transfer and compromise packaging reliability
2Power
If large area semiconductor die are used for high power dissipation applications, then power handling capability is improved, but void concentration increases in the central area under active transistor regions
Solution Approach 1:
The die attach material is divided into functional zones: a central region under the active transistor area and peripheral regions toward the die edges. Channels are strategically positioned to guide gas escape from the central high-power area to the periphery, segmenting the flow path and preventing void accumulation in critical regions
Solution Approach 2:
The die attach material exhibits different properties in different regions: the central area under active transistors has optimized channel density and geometry to facilitate gas escape, while peripheral areas have different characteristics. This local differentiation ensures that gas flows away from critical heat transfer zones without compromising overall attachment strength
3Reliability
If die attach material with channels is used to allow gas escape, then void formation is reduced and heat transfer is improved, but device complexity increases
Solution Approach 1:
Channels are incorporated into the die attach material as planar features within the adhesive layer, adding a two-dimensional flow pathway network to the otherwise uniform material. This dimensional approach allows gas to escape laterally through the adhesive layer rather than requiring vertical voids or complex three-dimensional structures, simplifying the overall design while maintaining effectiveness
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 void formation under active transistor areas, enhancing heat transfer and mechanical robustness, and eliminates the need for costly screening processes, improving yield and reliability in high-power semiconductor packaging.
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.