Lead Surface Wettability Layout to Prevent Sealing Resin Peeling
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Solution Overview
Problem
Existing semiconductor devices face issues with peeling of the sealing resin due to unintended spreading of the conductive bonding material during the manufacturing process, which compromises the bonding state and integrity of the semiconductor device.
Innovation Solution
The semiconductor device incorporates leads with a metal layer on the obverse surface that has better wettability to the conductive bonding material, featuring an uneven region and a smooth region to control the spread of the bonding material, ensuring strong adhesion with the sealing resin and preventing peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductive bonding material is applied to bond the semiconductor element to the lead, then electrical bonding is achieved, but the bonding material spreads unintentionally causing peeling of the sealing resin
Solution Approach 1:
The obverse surface of the lead is divided into two regions with different surface properties: a first region with higher wettability to the conductive bonding material and a second region with lower wettability. This local differentiation allows the bonding material to spread controllably only in the first region, preventing unintended spreading and peeling while maintaining reliable bonding.
2Strength
If the wettability of the lead surface to conductive bonding material is increased, then bonding strength is improved, but the bonding material spreads excessively causing peeling
Solution Approach 1:
Different regions of the lead's obverse surface are assigned different wettability characteristics. The first region has higher wettability to ensure strong adhesion, while the second region has lower wettability to contain the bonding material and prevent excessive spreading. This spatial differentiation resolves the contradiction between bonding strength and spreading control.
Solution Approach 2:
The obverse surface is segmented into functionally distinct regions: a first region optimized for bonding material adhesion and a second region optimized for containing the bonding material. This segmentation allows each region to perform its specific function without interfering with the other, achieving both strong bonding and controlled spreading.
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 suppresses peeling of the sealing resin while maintaining an appropriate bonding state, enhancing the reliability and durability of the semiconductor device.
Implementation Method 1
a material of the metal layer has better wettability to the conductive bonding material in a molten state than a material of the lead body
Data Source
AI summary
A semiconductor device includes: a semiconductor element; a lead; a bonding target; a conductive bonding material that electrically bonds the bonding target and the lead; and a sealing resin that covers the bonding target and the lead. The lead includes a lead body including an obverse surface facing the bonding target, and a metal layer disposed on the obverse surface. A material of the metal layer has better wettability to the conductive bonding material in a molten state than a material of the lead body. The conductive bonding material is bonded to the metal layer. The obverse surface includes an uneven region spaced apart from the metal layer in plan view, and a smooth region located between the metal layer and the uneven region.