Recessed Lead Semiconductor Package for Crack-Resistant Solder Joints

Solution Overview

Problem

The reliability of semiconductor packages is compromised due to cracks occurring at the soldered areas where leads with flat surfaces are connected to package substrates, leading to reduced durability.

Innovation Solution

A semiconductor package design featuring leads with recesses on their surfaces, covered by a plating layer of tin and bismuth, and a connecting structure body that is securely attached within these recesses, enhancing the attachment area and minimizing gaps for improved durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If leads with flat surfaces are used for soldering to package substrates, then the manufacturing process is simple, but cracks occur at the soldered area reducing reliability

Engineering Contradiction:

ImprovereliabilityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies curvature by forming a recess (concave surface) on the lead surface instead of using a flat surface. This curved/recessed structure allows the connecting structure body to fit into the recess, creating a mechanical interlock that prevents cracks at the soldered area while maintaining manufacturing feasibility through standard molding processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The connecting structure body is nested within the recess of the lead, creating a nested configuration where one component (connecting structure body) is placed inside another (recess). This nesting increases the attachment area and improves reliability by preventing cracks, while the overall structure remains integrated and manufacturable.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If the attachment area of the connecting structure body is increased, then durability against environmental stresses is improved, but the manufacturing process becomes more complex

Engineering Contradiction:

ImprovedurabilityVSAvoidmanufacturing ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The recess is formed on the lead surface before the connecting structure body is attached. This preliminary action of creating the recessed structure in advance allows for increased attachment area and improved durability, while the recess can be formed using standard molding processes that integrate smoothly into existing manufacturing workflows.

Inventive Principle:

Principle #10Preliminary action

3Strength

If a recess is formed on the lead surface to increase attachment area, then crack resistance is improved, but the manufacturing process requires additional steps

Engineering Contradiction:

Improvecrack resistanceVSAvoidprocess complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The recess is formed on the lead surface before the connecting structure body is attached. This preliminary action of creating the recessed structure in advance allows for increased attachment area and improved durability, while the recess can be formed using standard molding processes that integrate smoothly into existing manufacturing workflows.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies curvature by forming a recess (concave surface) on the lead surface instead of using a flat surface. This curved/recessed structure allows the connecting structure body to fit into the recess, creating a mechanical interlock that prevents cracks at the soldered area while maintaining manufacturing feasibility through standard molding processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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

The design increases the attachment area of the connecting structure body, reduces the likelihood of cracks, and enhances the semiconductor package's durability against environmental stresses such as heat, mechanical shock, and electrostatic discharge.

Implementation Method 1

a plating layer, comprising tin (Sn), conformally disposed on the second surface and recess of each of the first lead and the second lead

Methodology Applied

Scientific EffectConformal deposition: Deposition (physical)

Implementation Method 2

a first connecting structure body comprising tin (Sn) and bismuth (Bi), a portion of the first connecting structure body disposed in the recess of the first lead and is connected to and in contact with the plating layer

Methodology Applied

Scientific EffectSoldering: Soldering

Data Source

PatentUS20260026367A1Semiconductor package and method of manufacturing the same

Publication Date: 2026.01.22 SAMSUNG ELECTRONICS CO LTD

AI summary

A semiconductor package including a first lead comprising a first surface and a second surface that is opposite to the first surface, at least one semiconductor chip that is placed on the first surface of the first lead, a connecting structure body that is connected to the first lead, and a molding layer configured to cover the first lead and the semiconductor chip. The first lead comprises a recess that is formed on the second surface of the lead, and the connecting structure body is placed in the recess. The semiconductor chip, the first lead, and the connecting structure body are electrically connected to each other.