Sinter Bonding Sheet With Controlled Cavities for Thermal Cycling
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Solution Overview
Problem
The existing sinter bonding sheets fail to maintain reliable bonding between adherends when subjected to repetitive temperature changes, leading to partial separation and cracking, which degrades the bonding reliability of semiconductor devices.
Innovation Solution
A sinter bonding sheet with a sinter bonding layer containing conductive metal particles and an organic binder, where the maximum cavity size on the surface is 100 µm or less and the cavity area proportion is 5% or less, ensuring stable bonding even under temperature fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sinter bonding layer contains large cavities, then the manufacturing process is simpler, but the bonding reliability degrades under repetitive temperature changes
Solution Approach 1:
The patent applies parameter changes by strictly controlling the maximum cavity size to 100 µm or less and the cavity area proportion to 5% or less. This quantitative parameter control transforms the cavity structure from a potential defect into a controlled feature that maintains bonding reliability under thermal cycling while preserving the simplicity of the manufacturing process.
Solution Approach 2:
The patent applies local quality by allowing cavities to exist in the sinter bonding layer but restricting their size and distribution to specific limits. This creates a non-uniform structure where small cavities are permitted (maintaining manufacturing simplicity) but large cavities are eliminated (ensuring bonding reliability), thus resolving the contradiction between manufacturing ease and product reliability.
2Productivity
If the sinter bonding layer is subjected to repetitive temperature changes, then the sintering process can be completed, but partial separation and cracking occur at the interface
Solution Approach 1:
The patent applies beforehand cushioning by pre-controlling the cavity structure before sintering occurs. By limiting cavity size to 100 µm or less and area proportion to 5% or less, the structure is prepared in advance to withstand thermal stress during sintering and subsequent thermal cycling, preventing interface separation and cracking that would otherwise occur during the sintering process.
3Ease of manufacture
If larger cavities are present in the sinter bonding layer, then the organic binder removal is easier, but cracks form inside the layer during thermal cycling
Solution Approach 1:
The patent applies parameter changes by establishing specific thresholds for cavity size (100 µm or less) and area proportion (5% or less). These parameter changes optimize the balance between organic binder removal ease and internal structural integrity, allowing sufficient porosity for binder evacuation while preventing crack formation during thermal cycling through controlled cavity dimensions.
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 sinter bonding sheet effectively maintains bonding between the sinter bonding layer and adherends during repetitive temperature changes, preventing partial separation and cracking, thus enhancing the reliability of semiconductor devices.
Implementation Method 1
The intermediate product of the semiconductor device is subjected to sintering treatment in which the intermediate product of the semiconductor device is heated at a temperature at which sinterable particles in the sinter bonding layer can be sintered to each other
Implementation Method 2
heated at a temperature at which sinterable particles in the sinter bonding layer can be sintered to each other, to thereby at least partially eliminate the organic binder from the sinter bonding layer
Data Source
Figure 1~2A
Figure 2B~2D
Figure 3A~3B
AI summary
Provided is a sinter bonding sheet including a sinter bonding layer that includes: sinterable particles containing a conductive metal; and an organic binder, in which a maximum size among sizes of cavities observed in an observation image of a surface of the sinter bonding layer at a magnification of 100 times is 100 µm or less.