Semiconductor Lead Distal End Surface Design for Solder Containment
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Solution Overview
Problem
Existing semiconductor devices face issues with improper electrical connections due to misalignment of semiconductor elements and the spreading of solder paste during the bonding process, leading to unreliable bonding between electrodes and leads.
Innovation Solution
The semiconductor device design includes a first lead with a distal end surface that faces the electrode, a rising portion extending away from the electrode, and a conductive bonding material that stays within the rising portion's vicinity, preventing the solder from spreading and ensuring reliable bonding by aligning the distal end surface with the electrode and using a method that involves rotating the lead to position the distal end surface correctly during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder paste is applied to bond the electrode and lead, then electrical connection is achieved, but the solder paste may spread beyond the electrode causing improper connection to exposed conductive portions
Solution Approach 1:
The patent applies a solder resist pattern to the substrate before applying solder paste. This preliminary protective layer prevents solder paste from spreading beyond the electrode area during the bonding process, thereby eliminating the harmful effect of solder migration while maintaining reliable electrical connection.
Solution Approach 2:
The solder resist pattern acts as an intermediary barrier between the solder paste and the substrate. It selectively allows solder to bond to the electrode while blocking excess solder from reaching exposed conductive portions, thus mediating the bonding process to prevent improper connections.
2Adaptability or versatility
If the semiconductor element is largely misaligned during bonding, then positioning flexibility is maintained, but improper electrical connection occurs due to solder paste moving beyond the electrode
Solution Approach 1:
The solder resist pattern is pre-applied to define the exact bonding area before the semiconductor element is positioned. This preliminary structure guides precise alignment while still allowing flexibility in the bonding process, as the resist pattern clearly marks where solder should be applied regardless of minor positioning variations.
Solution Approach 2:
The solder resist pattern provides localized protection only in areas where solder spreading would cause problems, while leaving the electrode area exposed for bonding. This localized approach maintains manufacturing precision by protecting critical areas without restricting overall positioning flexibility.
3Object-affected harmful factors
If the distal end surface of the lead is made smaller than the electrode, then solder containment is improved, but bonding area is reduced
Solution Approach 1:
The solder resist pattern serves as an intermediary that compensates for the smaller distal end surface area. By providing a protective barrier around the electrode, it effectively contains solder within the bonding region, allowing the use of a smaller lead surface without risking solder spread to adjacent areas.
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 enhances the reliability of bonding between the semiconductor element's electrodes and leads, preventing misalignment and unintended electrical connections, while allowing for a more compact and efficient semiconductor device with improved manufacturing precision.
Implementation Method 1
The solder is formed, for example, by softening a solder paste through heating and then curing the solder paste.
Data Source
AI summary
A semiconductor device includes: a semiconductor element having an electrode facing a first direction; a first lead having a conductive distal end surface facing the electrode, and a rising portion which is connected to the distal end surface to extend away from the electrode; a conductive bonding material bonding the electrode of the semiconductor element to the distal end surface of the first lead; and a sealing resin covering the semiconductor element, at least a portion of the first lead, and the conductive bonding material.