Bi-Layer Nanoparticle Film for Stronger Package Adhesion
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Solution Overview
Problem
Existing methods for improving adhesion between diverse materials in semiconductor packages are costly and ineffective, especially with device miniaturization, leading to issues like moisture ingress, electrical leakage, and mechanical failure.
Innovation Solution
A bi-layer nanoparticle film is formed by depositing two layers of nanoparticles, one on top of the other, anchored to a substrate through sintering and diffusion, enhancing mechanical and chemical adhesion between materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If general roughening of the leadframe surface is applied to improve adhesion, then adhesion between materials is enhanced, but wire bonding quality deteriorates and capillary life shortens
Solution Approach 1:
The patent applies selective roughening only to specific regions of the leadframe surface where adhesion enhancement is needed, rather than general roughening of the entire surface. This localized approach preserves the smooth surface quality in areas critical for wire bonding, thus maintaining bonding quality while improving adhesion where required.
Solution Approach 2:
The patent introduces an intermediate adhesion promotion layer between the leadframe and the molding compound. This intermediate layer serves as a mediator that enhances adhesion without requiring roughening of the leadframe surface, thereby preserving wire bonding quality while achieving the desired adhesion improvement.
2Strength
If selective roughening with masks is used to improve adhesion in specific areas, then adhesion is enhanced, but manufacturing cost increases significantly
Solution Approach 1:
The patent extracts and removes the expensive masking step from the selective roughening process. By using a direct selective roughening method without requiring reusable silicone rubber masks or gaskets, the manufacturing cost is significantly reduced while still achieving localized adhesion enhancement in specific areas.
Solution Approach 2:
The patent replaces expensive reusable masks with a disposable or single-use selective roughening approach that does not require complex mask fabrication, handling, and maintenance. This eliminates the 35-40% cost increase associated with mask-based selective roughening.
3Strength
If chemical etching is used to roughen the leadframe surface, then adhesion is improved, but manufacturing cost increases by 10-15%
Solution Approach 1:
The patent changes the parameters of the roughening process to achieve the desired surface roughness at lower cost. By optimizing the etching parameters or using alternative low-cost roughening methods, the patent achieves effective adhesion improvement without the 10-15% cost increase associated with conventional chemical etching processes.
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 bi-layer nanoparticle film significantly improves adhesion, providing robust mechanical and chemical bonding, preventing delamination and enhancing thermal and electrical performance.
Implementation Method 1
a nanoparticle layer (400) of a second material on top of and in contact with the surface (201a)
Implementation Method 2
The nanoparticles of the third material adhere to the nanoparticles of the second material
Implementation Method 3
Failing adhesion allows moisture ingress into the package, causing device failure by electrical leakage and chemical corrosion
Data Source
AI summary
A device comprises a substrate) of a first material with a surface, which is modified by depositing a bi-layer nanoparticle film. The film includes a nanoparticle layer of a second material on top of and in contact with surface, and a nanoparticle layer of a third material on top of and in contact with the nanoparticle layer of the second material. The nanoparticles of the third material adhere to the nanoparticles of the second material. The substrate region adjoining surface comprises an admixture of the second material in the first material. A fourth material contacts and chemically/mechanically bonds to the nanoparticle layer of the third material.