Bonding Wire Barriers for Solder Spread in Semiconductor Packages
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Solution Overview
Problem
Existing semiconductor device manufacturing methods face challenges in preventing solder spread, which can lead to stress on insulating substrates and potential cracks, and affect electrical characteristics, while also increasing manufacturing costs and complexity.
Innovation Solution
The semiconductor device incorporates wire members made of materials like aluminum, which are repellent to bonding materials, strategically placed between electronic components and the edges of metal patterns to prevent solder or bonding material from reaching the edges, thereby reducing stress on substrates and improving reliability without adding new manufacturing steps or increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solder-repellent insulating film is formed on the metal layer around the mounting position, then solder spread is suppressed, but manufacturing cost increases due to additional process steps
Solution Approach 1:
A wire member made of solder-repellent material (such as aluminum) is introduced as an intermediary element between the mounting position and the edge of the metal layer. This wire member physically blocks solder from spreading to the edge, achieving the same protective function as an insulating film but using a simpler, more cost-effective material that can be integrated into the existing wire bonding process
2Reliability
If a slit is formed in the metal layer around the mounting position, then solder spread is suppressed, but electrical characteristics are affected due to disruption of current paths
Solution Approach 1:
Instead of forming a slit that disrupts the metal layer and affects electrical characteristics, a wire member is placed on top of the continuous metal layer. This intermediary approach blocks solder spread while preserving the integrity and electrical continuity of the metal layer underneath
Solution Approach 2:
The solder spread prevention function is segmented from the metal layer structure itself and implemented as a separate wire member element. This allows the metal layer to remain continuous for electrical purposes while the wire member provides the blocking function
3Ease of manufacture
If wire members are used to prevent solder spread, then manufacturing cost is reduced by using existing wire bonding process, but device structure becomes more complex
Solution Approach 1:
The wire bonding process, traditionally used solely for electrical connections, is given a dual function by also placing wire members for solder spread prevention. This multi-functional use of the same process and material reduces overall device complexity despite adding the prevention function
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 configuration effectively prevents solder spread to the edges of metal patterns, reducing the risk of substrate cracking and maintaining electrical integrity while keeping manufacturing costs low by using the same wire bonding process for both wiring and wire members.
Implementation Method 1
wire members 203 and 204, which contain a material repellent to the bonding material 162, are formed between the external connection terminal 182 and each of the edges 155a and 155b
Data Source
Figure 1
Figure 2
Figure 3(A)~3(B)
AI summary
Reliability is improved while curbing manufacturing cost. A semiconductor device (100) includes a substrate (110), an insulating substrate (141 and 142) mounted on the substrate (110), a metal pattern (152 and 155) formed on the insulating substrate (141 and 142), an electronic part mounted on the metal pattern (152 and 155) across a bond, and a wire member (201 to 206), separate from a wiring wire, which contains a material repellent to the bond and is formed on the metal pattern (152 and 155) and around the electronic part.