Semiconductor Package Lead Layout to Prevent Lead Entanglement

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Solution Overview

Problem

Semiconductor packages often become entangled during manufacturing and testing due to interleaved contact leads, causing manufacturing delays and equipment jams in high-volume production.

Innovation Solution

The external leads of semiconductor packages are designed with alternating T-shaped or Z-shaped cross-sections, where adjacent leads have opposite orientations, allowing for unrestrained movement and preventing entanglement by creating spaces that prevent locking between packages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If external leads are arranged in parallel configuration, then manufacturing and testing can proceed, but packages become entangled and jam equipment

Engineering Contradiction:

Improvemanufacturing throughputVSAvoidentanglement and equipment jamming

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by giving adjacent external leads different cross-sectional shapes (e.g., T-shaped vs. inverted T-shaped, or L-shaped vs. reverse L-shaped). This asymmetric design prevents symmetrical interlocking between leads of adjacent packages, eliminating entanglement while maintaining parallel configuration for high-volume production

Inventive Principle:

Principle #4Asymmetry

2Ease of manufacture

If lead cross-section is uniform, then manufacturing is simpler, but adjacent leads can interlock and cause entanglement

Engineering Contradiction:

Improvelead fabrication simplicityVSAvoidlead interlocking and entanglement

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by varying the cross-sectional shape at specific locations along the lead length. The leads have different cross-sections (T-shaped, inverted T-shaped, L-shaped, reverse L-shaped) at different positions, creating localized geometric features that prevent interlocking while maintaining overall manufacturing feasibility through standardized processes

Inventive Principle:

Principle #3Local quality

3Volume of moving object

If leads are spaced closely for compact packages, then package size is reduced, but leads can still become entangled

Engineering Contradiction:

Improvepackage sizeVSAvoidentanglement

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent maintains compact package size by using asymmetric cross-sectional shapes on closely spaced leads. The alternating T-shaped and inverted T-shaped (or L-shaped and reverse L-shaped) configurations prevent interlocking even when leads are in close proximity, enabling compact packaging without sacrificing anti-entanglement performance

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS20250006599A1Alternating Lead Configuration for Semiconductor Package

Publication Date: 2025.01.02 TEXAS INSTRUMENTS INC

AI summary

A semiconductor package comprises a leadframe segment having a plurality of external leads. The external leads each have a first cross-section shape or a second cross-section shape. A semiconductor die is electrically coupled to the leadframe segment. An encapsulant covers the semiconductor die and a portion of the leadframe segment. External leads are exposed from the encapsulant on at least one side of the semiconductor package. The exposed external leads are arranged so that adjacent leads alternate between the first cross-section shape and the second cross-section shape. The second cross-section shape is a mirror image of the first cross-section shape.