Gold Bump Protrusions for Semiconductor Connection Reliability
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Solution Overview
Problem
The reliability of electrical connections between semiconductor devices and printed circuit boards is low due to the small surface area of conventional gold bumps, which results in fractured anisotropic conductive film granules and reduced connectivity.
Innovation Solution
A semiconductor device with a protective layer having protrusions over contacts, where under bump metallurgy (UBM) pads and gold bumps are formed with corresponding bulges, increasing the effective connection area and reliability by evenly distributing pressure on anisotropic conductive film granules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional gold bumps with small surface area are used, then the device complexity is reduced, but the reliability of electrical connection deteriorates
Solution Approach 1:
The gold bump is segmented into multiple regions with different heights, creating a multi-level structure. The first gold bump layer has a first height, while the second gold bump layer has a second height greater than the first height, dividing the single bump into structured zones that enhance connection reliability
Solution Approach 2:
The invention transitions from a conventional single-plane gold bump to a multi-layered three-dimensional structure. By stacking gold bumps in multiple layers with different heights and positions, the effective connection area is expanded vertically, increasing reliability without proportionally increasing device footprint
2Reliability
If the surface area of gold bumps is increased, then the reliability of electrical connection is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The protective layer with openings is formed beforehand, establishing precise registration marks and alignment references before gold bump deposition. This preliminary structuring enables accurate positioning of multi-layer gold bumps, reducing manufacturing precision requirements for the subsequent bump formation steps
Solution Approach 2:
The protective layer acts as an intermediary structure that facilitates precise alignment and positioning of gold bumps. The openings in the protective layer serve as registration features that guide the placement of each gold bump layer, enabling high precision manufacturing through a mediating alignment mechanism
3Reliability
If the surface area of gold bumps is increased, then the reliability of electrical connection is improved, but the device complexity increases
Solution Approach 1:
Different regions of the gold bump structure have different local properties - the first and second gold bump layers have different heights and positions, with the second layer providing enhanced connection area at specific locations. This local differentiation optimizes electrical connection reliability without requiring uniform complexity throughout the entire 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 increased surface area of the gold bumps enhances the reliability of electrical connections between semiconductor devices and printed circuit boards by ensuring consistent fracture of the anisotropic conductive film's insulating exterior, leading to more stable conductive contacts.
Implementation Method 1
The insulating exterior of the granules 252 at where pressure is being applied is fractured by the protrusions Q on the gold bumps 140 and the terminals 210 for the die 110 exposing the conductive interior
Implementation Method 2
Subsequent to electroplating gold in these openings, a plurality of gold bumps 140 is formed on the die 110
Data Source
AI summary
A semiconductor device including a circuit structure and a protective layer is provided. The circuit structure has multiple contacts. The protective layer is located on the circuit structure and has multiple openings and multiple protrusions, wherein the contacts are exposed by the openings and the protrusions are located on the contacts.