Lead Bonding Structure for Warpage-Tolerant Semiconductor Assembly
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Solution Overview
Problem
In semiconductor devices with direct lead bonding (DLB) structures, warpage caused by differing linear expansion coefficients of materials during bonding leads to gaps or insufficient bonding areas between lead parts and semiconductor elements, reducing reliability.
Innovation Solution
A semiconductor device design featuring a lead part with a plate shape and a bonding component that includes an opening with step parts, where the bonding component is bonded to the semiconductor element with a first material and to the lead body with a second material, allowing for movement during warpage to maintain contact and secure bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct lead bonding is performed with conventional structures, then bonding process is simple, but warpage causes gaps or insufficient bonding area reducing reliability
Solution Approach 1:
The lead part is divided into multiple functional sections: a lead body with an opening part, and a bonding component with step parts that fits within the opening. This segmentation allows the bonding component to move independently to compensate for warpage while maintaining bonding contact, thus improving bonding reliability without overly complicating the overall structure.
Solution Approach 2:
The bonding component is designed to be movable relative to the lead body within the opening part. This dynamic structure enables the bonding component to adjust its position in response to warpage during bonding, ensuring continuous contact with the semiconductor element and maintaining sufficient bonding area, thereby resolving the reliability issue caused by rigid conventional structures.
2Reliability
If warpage compensation structures are added to maintain bonding contact, then bonding reliability improves, but manufacturing complexity increases
Solution Approach 1:
The bonding component features step parts with different heights created through localized processing. This local quality variation allows the bonding component to adapt to warpage-induced height differences at specific bonding locations while maintaining a relatively simple overall manufacturing process using conventional forming and bonding techniques.
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 design enhances bonding reliability by ensuring stable contact between the lead part and semiconductor element, even with warpage, and improves assemblability by maintaining a sufficient bonding area.
Implementation Method 1
The bonding component is bonded at a lower surface thereof to the semiconductor element by a first bonding material
Implementation Method 2
bonded at an outer peripheral part thereof to an inner periphery of the opening part by a second bonding material
Data Source
AI summary
A semiconductor device includes a semiconductor element and a lead part. The semiconductor element is mounted on a circuit pattern provided on an insulating substrate. The lead part has a plate shape and is bonded to the semiconductor element with a first bonding material interposed therebetween. The lead part includes a lead body and a bonding component. The lead body includes an opening part provided corresponding to a mounting position of the semiconductor element. The bonding component is provided in the opening part and on the semiconductor element. The bonding component is bonded at a lower surface thereof to the semiconductor element by the first bonding material and bonded at an outer peripheral part thereof to an inner periphery of the opening part by a second bonding material.