MOSFET Source Pad Bonding Layout for Lower ON-Resistance
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving low ON-resistance for high current applications, particularly in the connection between the source pad and source lead, which affects the efficiency and performance of power semiconductor devices.
Innovation Solution
A method of manufacturing a semiconductor device involves bonding conductive members to the source pad in specific positions and configurations using a bonder with a cutter, guide, and wedge tool, optimizing the positional relationship to enhance the junction area and reduce ON-resistance, including the use of ribbons as conductive members to distribute the current effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single conductive member is used to couple the source pad and source lead, then the device structure is simple, but the ON-resistance is high and current handling capability is limited
Solution Approach 1:
The source connection is divided into multiple conductive members (first conductive member and second conductive member) that couple the source pad to the source lead at different positions. This segmentation distributes the current flow across multiple parallel paths, reducing the overall ON-resistance while maintaining a manageable structural complexity through systematic arrangement.
Solution Approach 2:
Different conductive members are positioned at specific locations on the source pad (first conductive member at a first position, second conductive member at a second position). This local quality approach optimizes the current distribution by strategically placing bonding points across the source pad surface, reducing resistance without requiring uniform complexity throughout the entire structure.
2Reliability
If the diameter of the conductive member is increased to reduce ON-resistance, then the current handling capability improves, but the bonding process becomes more difficult and the device size increases
Solution Approach 1:
Instead of using a single thick conductive member that is difficult to bond, the connection is segmented into multiple standard-diameter conductive members. Each member can be bonded using conventional bonding processes, avoiding the manufacturing difficulties of bonding large-diameter single members while achieving equivalent or better current handling through parallel paths.
Solution Approach 2:
The solution transitions from increasing the cross-sectional area of a single conductive member (one-dimensional approach) to distributing multiple conductive members across the source pad surface (two-dimensional arrangement). This dimensional change allows current to flow through multiple parallel paths, reducing ON-resistance without requiring individually large conductive members that would be difficult to bond.
3Reliability
If multiple bonding positions are used on the source pad, then the junction area increases and ON-resistance decreases, but the bonding process complexity increases
Solution Approach 1:
The bonding process is segmented into distinct steps with each conductive member being bonded at a specific position on the source pad. This systematic segmentation of the bonding process, where the first conductive member is bonded at a first position and the second conductive member is bonded at a second position, makes the multi-position bonding manageable and repeatable, reducing the complexity burden of multiple bonding operations.
4Reliability
If the conductive members are bonded closer to the source lead, then the current path length is reduced, but the bonding tool may interfere with the source lead
Solution Approach 1:
Different conductive members are bonded at different positions on the source pad relative to the source lead. The first conductive member can be bonded at a position closer to the source lead to minimize current path length, while the second conductive member is bonded at a different position that avoids interference with the bonding tool and source lead. This local quality approach allows optimization of current path length at specific locations without compromising the overall bonding operability.
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 approach significantly improves the ON-resistance characteristics, enabling the semiconductor device to handle larger currents efficiently by optimizing the bonding process and increasing the junction area between the conductive members and the source pad.
Implementation Method 1
a wedge tool located adjacent to the cutter and capable of pressing the first conductive member
Data Source
AI summary
A source pad electrically coupled with a source of a MOSFET of a semiconductor chip and located at a position below a lead in cross-sectional view is electrically connected with the lead for source via a conductive member bonded to the source pad and a wire bonded to the conductive member.