Solder Pad Trench Design for Wire Bonding Deformation
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Solution Overview
Problem
Conventional semiconductor packaging structures suffer from short-circuit phenomena due to the deformation of aluminum solder pads during the wire bonding process, where copper bonding wires apply high force, causing the pads to extend and connect with surrounding devices.
Innovation Solution
A packaging structure and fabrication method that includes a base substrate with a solder pad body region and a trench region around it, a passivation layer exposing these regions, and a main body solder pad with trenches between the passivation layer and the pad, allowing for a bonding conductive wire connection. The trench region accommodates the deformation of the solder pad during wire bonding, preventing short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is performed with copper bonding wires applying high force, then reliable electrical connection is achieved, but solder pads deform and extend to connect with surrounding devices causing short circuits
Solution Approach 1:
The solder pad structure is segmented into a main body portion and a tail portion, with the tail portion extending into the trench region. This segmentation allows the tail to absorb deformation forces during wire bonding, preventing the pad from deforming into surrounding devices and causing short circuits, while maintaining reliable electrical connection.
Solution Approach 2:
The trench region acts as an intermediary space that accommodates the tail portion of the solder pad. This intermediate structure provides a dedicated zone for pad deformation during wire bonding, isolating the deformation from surrounding devices and preventing harmful short circuit effects.
2Reliability
If solder pads are made larger to accommodate deformation, then wire bonding reliability improves, but the risk of short circuits with surrounding devices increases
Solution Approach 1:
The solder pad is divided into a compact main body and an extended tail portion located in the trench region. This segmentation allows the pad to have sufficient length for reliable wire bonding while confining the deformation-prone tail portion to an isolated trench area, preventing short circuits with surrounding devices.
Solution Approach 2:
The trench region provides a localized environment with different properties - it is an isolated space that specifically accommodates pad deformation. This local quality change allows the pad tail to extend and deform without affecting surrounding devices, resolving the contradiction between pad size and short circuit risk.
3Object-affected harmful factors
If trenches are added around solder pads to accommodate deformation, then short circuit prevention improves, but manufacturing complexity increases
Solution Approach 1:
The trench structure segments the substrate into isolated regions around each solder pad. This segmentation approach prevents short circuits by providing dedicated deformation zones, while the trench design itself is simple and can be integrated into existing manufacturing processes, balancing effectiveness with manufacturing complexity.
Solution Approach 2:
The trench structure introduces a vertical dimension (depth) to solve the horizontal short circuit problem. By creating downward-extending isolation structures, the patent prevents lateral deformation into surrounding devices while maintaining a relatively simple planar layout, reducing the perceived complexity.
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 method effectively prevents short circuits between solder pads and surrounding devices by providing a space for the solder pad deformation, maintaining the integrity of the packaging structure and avoiding electrical connections with adjacent pads.
Implementation Method 1
the deformation of aluminum solder pads during the wire bonding process, where copper bonding wires apply high force, causing the pads to extend
Implementation Method 2
pressure-welding the small ball onto the first solder joint; pressure-welding the other end of the lead wire onto the second solder joint
Data Source
AI summary
Method for fabricating A packaging structure is provided. The packaging structure includes a base substrate including a solder pad body region and a trench region adjacent to and around the solder pad body region. The packaging structure includes a passivation layer on the base substrate and exposing the solder pad body region and the trench region. The packaging structure includes a main body solder pad on the solder pad body region of the base substrate, and one or more trenches on the trench region of the base substrate and between the passivation layer and the main body solder pad. The packaging structure includes a bonding conductive wire having one end connected to the main body solder pad.