3D Printed Lead Frame Routing for Complex Pad Layouts

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Solution Overview

Problem

Conventional lead frame production technologies face limitations in design flexibility, compatibility with different package types, and material removal processes, which restrict the adaptation of lead configurations to complex pad layouts and increase wire length and surface roughness.

Innovation Solution

The use of 3D printing (additive manufacturing) to create electrically conductive lead frames with overlapping surfaces and gaps for insulation, allowing for customized designs and reduced material usage without plastic deformation, enabling flexible routing and improved adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional material removal processes (etching, stamping) are used to produce lead frames, then manufacturing precision can be achieved, but design flexibility is reduced and adaptation to complex pad layouts is limited

Engineering Contradiction:

Improvelead frame design flexibilityVSAvoidprocess complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent inverts the conventional approach by using additive manufacturing (3D printing) instead of subtractive processes (etching, stamping). This allows leads to be built layer by layer with complete design freedom, enabling complex three-dimensional routing and crossing patterns that cannot be achieved with traditional material removal methods.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent transitions from two-dimensional lead frame designs to three-dimensional structures by utilizing vertical stacking and overlapping leads with gaps for insulation. This dimensional change enables complex routing patterns and signal crossings without requiring additional planar space, significantly increasing design flexibility.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If photolithographic etching is used to create lead frames, then geometric patterns can be transferred with precision, but routing flexibility and lead crossing capability are restricted

Engineering Contradiction:

Improverouting flexibilityVSAvoidpattern transfer precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Instead of using photolithographic patterning to define lead shapes, the patent uses direct 3D printing to build leads layer by layer. This eliminates the constraints of planar pattern transfer while maintaining manufacturing precision through controlled material deposition and curing processes.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent enables three-dimensional routing by stacking leads in the vertical dimension, allowing signals to cross underneath or above other leads. This eliminates the need for complex planar routing workarounds and enables direct implementation of complex routing patterns.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If standard lead frame designs are used, then manufacturing simplicity is maintained, but compatibility with different package types is reduced

Engineering Contradiction:

Improvepackage type compatibilityVSAvoidmanufacturing simplicity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent enables dynamic adaptation of lead frame designs to different package types by using 3D printing parameters (layer thickness, infill patterns, support structures) that can be easily modified for each application. This allows the same manufacturing process to produce optimized designs for various package configurations without requiring dedicated tooling for each package type.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The 3D printing process itself becomes a universal manufacturing platform that can produce lead frames for different package types (QFP, BGA, CSP, etc.) with a single system, eliminating the need for multiple specialized manufacturing lines and tooling sets.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If wire bonding is used to manage signal crossings, then electrical insulation can be achieved, but wire length increases and wire sweeping occurs

Engineering Contradiction:

Improveelectrical insulationVSAvoidwire length

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent eliminates the need for wire bonding by implementing signal crossings directly in the lead frame structure through three-dimensional routing. Leads can pass underneath or above each other with built-in gaps for insulation, allowing signals to cross without adding external wire length or creating wire sweeping issues.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent uses insulating gaps and supporting structures as intermediaries to achieve electrical isolation between crossing leads, replacing the need for wire bonding as the isolation mechanism. This integrated approach maintains reliability while eliminating the drawbacks of additional wire length.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10074596B2Method of fabricating a lead frame by additive process

Publication Date: 2018.09.11 STMICROELECTRONICS SRL

AI summary

An electronic component, such as an integrated circuit, includes at least one circuit having coupled therewith electrical connections including a lead frame of electrically conductive material. The lead frame is produced by an additive process of conductive material, e.g., by 3D printing, by forming a three-dimensional structure of leads having overlapping surfaces with a gap therebetween.