Nickel-Layer Chip Package Structure for Bump Adhesion and Electromigration
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable packages with high integration density due to the decreasing feature sizes of semiconductor devices, which complicates the fabrication processes and adhesion between components.
Innovation Solution
A chip package structure is formed using a wiring substrate with a conductive adhesive layer and a nickel layer to improve adhesion between solder structures and polymer layers, and a nickel layer is used to prevent material migration during high current density operations, enhancing the reliability of conductive bumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If feature sizes are reduced to improve integration density, then more components can be integrated into a given area, but fabrication processes become more difficult and adhesion between components deteriorates
Solution Approach 1:
The patent divides the conductive adhesive layer into multiple discrete conductive bumps rather than using a continuous layer. This segmentation allows each bump to be independently formed and positioned, improving precision and adhesion while facilitating easier fabrication control at reduced feature sizes.
Solution Approach 2:
The patent transitions from a two-dimensional continuous conductive adhesive layer to a three-dimensional array of discrete conductive bumps with controlled height and spacing. This dimensional change enables better stress distribution and improved adhesion to the underlying polymer layer, addressing fabrication difficulties at smaller feature sizes.
2Quantity of substance
If feature sizes are reduced to improve integration density, then more components can be integrated into a given area, but adhesion between solder structures and polymer layers deteriorates
Solution Approach 1:
The patent applies different material compositions and structural properties to different regions of the conductive bumps. The bumps have a specific height range (5-20 micrometers) and are formed with controlled spacing from the polymer layer (0-5 micrometers), creating optimal local adhesion conditions that improve overall reliability while maintaining high integration density.
Solution Approach 2:
The patent uses a composite structure consisting of conductive bumps formed from conductive adhesive material with specific material properties. The composite nature of the bumps (combining adhesion promoters, conductive materials, and structural support) enables simultaneous improvement of adhesion and integration density.
3Reliability
If nickel layer is added to prevent material migration, then reliability of conductive bumps is improved, but device complexity increases
Solution Approach 1:
The nickel layer serves as an intermediary barrier between the conductive adhesive bumps and the underlying structure. This intermediate layer prevents direct contact and potential material migration while maintaining electrical conductivity and mechanical integrity, thus improving reliability without significantly complicating the overall device structure.
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 solution improves the yield and reliability of conductive bumps by balancing tensile stresses and reducing electromigration issues, resulting in more stable and efficient chip package structures.
Implementation Method 1
a nickel layer is used to prevent material migration during high current density operations, enhancing the reliability of conductive bumps
Implementation Method 2
A chip package structure is formed using a wiring substrate with a conductive adhesive layer and a nickel layer to improve adhesion between solder structures and polymer layers
Data Source
AI summary
A chip package structure is provided. The chip package structure includes a wiring substrate having a pad and a conductive adhesive layer over the pad and having a first inner wall, a second inner wall, a first sidewall, and a second sidewall. The first inner wall and the second inner wall face each other, and the first sidewall and the second sidewall are opposite to each other. The chip package structure also includes a nickel layer over the conductive adhesive layer, and the nickel layer covers the first inner wall, the second inner wall, the first sidewall, and the second sidewall of the conductive adhesive layer. The chip package structure further includes a chip over the wiring substrate and a conductive bump connected between the nickel layer and the chip.