Transient Liquid Phase Bonding Area Wettability Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing transient liquid phase (TLP) bonding process faces challenges with the unintended expansion of melted materials beyond the bonding area, leading to inconsistent bonding, potential electrical shorts, and production issues due to unpredictable and uncontrolled flow of metal.
Innovation Solution
The solution involves creating a bonding area with high wettability characteristics and a non-bonding area with lower wettability characteristics, using materials like cadmium sulfide for the non-bonding area to restrict the flow of melted metal, thereby confining it within the bonding area, and employing techniques such as plasma exposure or surface treatments to differentiate the wettability of the materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard TLP bonding process is used, then bonding is achieved through melting and diffusion of the third material, but the melted material expands beyond the bonding area causing electrical shorts and inconsistent bonding
Solution Approach 1:
The bonding area is given different wettability characteristics compared to the non-bonding area. The bonding area has high wettability to the bonding material, while the non-bonding area has low wettability, creating a local property difference that confines the melted material within the bonding area during TLP bonding process
Solution Approach 2:
The wettability parameter of the bonding area is changed to be highly wettable by the bonding material, while the non-bonding area maintains low wettability. This parameter change in surface properties creates a barrier that prevents metal overflow without affecting the bonding process
2Reliability
If the bonding area is made highly wettable to ensure good bonding, then bonding quality improves, but the melted material flows more easily into non-bonding areas
Solution Approach 1:
Different regions of the substrate are assigned different wettability characteristics: the bonding area has high wettability to promote bonding material adhesion, while the non-bonding area has low wettability to resist metal flow. This local differentiation allows both good bonding and flow control to coexist
3Quantity of substance
If additional bonding material is added to account for losses, then material coverage is improved, but production cost increases and material waste increases
Solution Approach 1:
The low wettability of the non-bonding area, which initially appears to be a barrier, is converted into a beneficial feature that prevents material loss. By making the non-bonding area resistant to metal flow, the process naturally confines the bonding material where needed, eliminating the need to add extra material to compensate for overflow losses
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 ensures reliable and consistent bonding, maintains electrical and thermal conductivity, reduces dependency on fabrication conditions, and allows for flexible application across various materials and bonding types, preventing metal overflow and ensuring device performance.
Implementation Method 1
a non-bonding area formed of a material having a lower wettability characteristic than the bonding area material which limits the melted metal from flowing into the non-bonding area
Data Source
AI summary
Devices, methods and systems are disclosed herein to describe the wettability characteristics of the material forming a bonding area, a non-bonding area, and a melted bonding material. The melted bonding material may have a high degree of cohesion and may result in a very high contact angle (e.g., between 90°- 180°) in the non-bonding area thereby preventing or limiting the flow of a melted material into the non-bonding area, which often results when the melted bonding material forms a low contact angle (e.g., between 0°-90°) in the bonding area. In other words, by choosing a material for the non-bonding area to have low wettability characteristics when compared to the melted materials of the bonding area or by treating the material forming the non-bonding area to have much lower wettability characteristics, the melted materials of the bonding area may be prevented from flowing into the non-bonding area.