Lead Frame Manufacturing Using Embedded Conductive Members

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Solution Overview

Problem

Conventional methods for manufacturing microelectronic package lead frames result in significant material waste and high costs due to the removal of excess material from metal sheets, which is inefficient and costly.

Innovation Solution

The method involves using elongated members made of electrically conductive material, which are partially embedded in a non-conductive filling material to create a lead frame element, reducing waste and costs by eliminating the need for material removal, and allowing for efficient electrical contact through exposed conductive surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If a metal sheet is used to manufacture a lead frame by removing portions, then the lead frame can be obtained with required structural integrity, but approximately ten times the sheet surface is thrown away as waste

Engineering Contradiction:

Improvemetal sheet wasteVSAvoidmanufacturing process complexity

Core Design Contradiction:

Loss of substanceVSEase of manufacture

Solution Approach 1:

Instead of starting with a complete metal sheet and removing excess material, the invention inverts the approach by providing only the necessary elongated conductive members in the final configuration and embedding them directly in the carrier substrate. This eliminates the need for material removal and reduces waste from 90% to near zero.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The lead frame is segmented into discrete elongated conductive members rather than being formed from a continuous metal sheet. Each member is positioned independently and embedded in the carrier substrate, allowing precise material placement only where needed for electrical connection.

Inventive Principle:

Principle #1Segmentation

2Loss of substance

If elongated members are provided and embedded in non-conductive filling material, then material waste is significantly reduced, but the manufacturing process requires precise positioning and embedding steps

Engineering Contradiction:

Improvematerial wasteVSAvoidmanufacturing process steps

Core Design Contradiction:

Loss of substanceVSDevice complexity

Solution Approach 1:

The invention merges multiple functions into the non-conductive filling material: it serves as the carrier substrate material, provides mechanical support, ensures electrical insulation between conductive members, and fixes the elongated members in their predetermined positions. This consolidation simplifies the overall manufacturing process despite the precise positioning requirement.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The non-conductive filling material automatically performs multiple functions simultaneously: it embeds and secures the conductive members, provides electrical insulation, and forms the structural carrier substrate. This self-service approach reduces the need for additional manufacturing steps and complex assembly processes.

Inventive Principle:

Principle #25Self-service

3Ease of manufacture

If conventional metal sheet methods are used, then manufacturing is straightforward, but costs are high due to material waste

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidmaterial consumption

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The invention changes the fundamental parameter of material form from bulk metal sheets to thin elongated members (wires or narrow strips). This parameter change enables precise material placement and eliminates the need for excessive material consumption, reducing waste while maintaining manufacturing feasibility through standardized wire drawing and embedding processes.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8138596B2Method for manufacturing an element having electrically conductive members for application in a microelectronic package

Publication Date: 2012.03.20 UNITED MICROELECTRONICS CORP

AI summary

A microelectronic package (31) has a microelectronic device, which is encapsulated in a quantity of material (27), and a lead frame element (15) for enabling the microelectronic device to be electrically contacted from outside of the package (31). The lead frame element (15) comprises at least two elongated members (11) comprising electrically conductive material and a filling material (12) comprising electrically insulating material, wherein the members (11) are partially embedded in the filling material (12). The lead frame element (15) is manufactured by providing elongated members (11), positioning the members (11) according to a predetermined configuration, providing filling material (12) to spaces (13) which are present between the members (11), and possibly removing portions of the filling material (12) and the members (11) in order to expose the electrically conductive material of the members (11). An important advantage of manufacturing the lead frame element (15) on the basis of elongated members (11) and a filling material (12) is that no waste or only a small quantity of waste is produced.