Lead Frame Cutout Layout for Reliable Semiconductor Bonding

Solution Overview

Problem

The existing semiconductor modules face issues with scattering failure of bonding members like solder, which affects the reliability of connections between the semiconductor chip and the lead frame, leading to potential failures in the semiconductor module's operation.

Innovation Solution

The semiconductor module incorporates a lead frame with a chip connection portion that includes a center portion and cut-out portions to reduce voids and scattering of the bonding member, ensuring a secure and reliable connection by minimizing contact areas with protective films, thereby suppressing solder scattering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the chip connection portion is designed with a conventional structure, then the bonding process is simple, but solder scattering occurs and bonding reliability deteriorates

Engineering Contradiction:

Improvebonding reliabilityVSAvoidchip connection portion structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The chip connection portion is divided into multiple functional regions: a center portion covering the center of the transverse protective film, first and second cut-out portions extending from opposite end sides toward the center, and first and second bonding portions positioned between the cut-out portions. This segmentation allows each region to serve specific functions in preventing solder scattering while maintaining bonding effectiveness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the chip connection portion are designed with distinct characteristics: the center portion provides coverage over the protective film center to prevent solder scattering, the cut-out portions create spacing to further contain solder, and the bonding portions provide adequate bonding area. This local differentiation optimizes each region's contribution to overall bonding reliability.

Inventive Principle:

Principle #3Local quality

2Reliability

If the chip connection portion contacts the transverse protective film extensively, then bonding area is sufficient, but solder scattering increases

Engineering Contradiction:

Improvebonding reliabilityVSAvoidsolder scattering

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The chip connection portion is divided into multiple functional regions: a center portion covering the center of the transverse protective film, first and second cut-out portions extending from opposite end sides toward the center, and first and second bonding portions positioned between the cut-out portions. This segmentation allows each region to serve specific functions in preventing solder scattering while maintaining bonding effectiveness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cut-out portions are designed to extend from the end sides toward the center, creating predetermined spacing regions that actively prevent solder from scattering toward the end sides before the bonding process occurs. This preliminary anti-action structure counteracts the potential harmful effect of solder scattering.

Inventive Principle:

Principle #9Preliminary anti-action

3Reliability

If the chip connection portion is designed with center portion and cut-out portions, then solder scattering is suppressed, but manufacturing complexity increases

Engineering Contradiction:

Improvebonding reliabilityVSAvoidchip connection portion fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The chip connection portion is divided into multiple functional regions: a center portion covering the center of the transverse protective film, first and second cut-out portions extending from opposite end sides toward the center, and first and second bonding portions positioned between the cut-out portions. This segmentation allows each region to serve specific functions in preventing solder scattering while maintaining bonding effectiveness.

Inventive Principle:

Principle #1Segmentation

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 the reliability of the bonding process, reducing the likelihood of solder scattering and maintaining the integrity of connections between the semiconductor chip and the lead frame, ensuring stable module performance.

Implementation Method 1

a wiring member such as a lead frame and the semiconductor chip are bonded via solder which is a bonding material

Methodology Applied

Scientific EffectSoldering: Soldering

Data Source

PatentUS11894280B2Semiconductor module

Publication Date: 2024.02.06 FUJI ELECTRIC CO LTD

AI summary

Provided is a semiconductor module comprising a semiconductor chip, a lead frame including a chip connection portion configured to connect the lead frame to the semiconductor chip, and a bonding member configured to connect the chip connection portion and the semiconductor chip, wherein the semiconductor chip includes a semiconductor substrate, an active portion provided on the semiconductor substrate, and a transverse protective film provided above the active portion and provided to traverse the active portion in a top view, wherein the chip connection portion includes a center portion which covers a center of the transverse protective film in a top view and a first cut-out portion provided from a first end side of the chip connection portion towards the center portion.