Tiered Lead IC Packaging for Circuitry Density

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Solution Overview

Problem

Existing integrated circuit packaging systems face challenges in maximizing circuitry density, reducing package size, and minimizing lead lengths while maintaining connectivity and manufacturing efficiency, particularly when stacking multiple chips, as leads are often restricted to the lower half of the package, limiting the number of chips that can be accommodated and increasing wire lengths.

Innovation Solution

The solution involves forming leads with a first tip, a second tip, and a connect area between, along with tier sections, where the top component assembly is mounted over the connect area, and an encapsulant is applied to expose the first tip while covering the second tip, allowing for flexible component placement and reduced wire lengths without increasing package size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If leads are restricted to the lower half of the package, then manufacturing is simplified, but the number of chips that can be accommodated is limited and wire lengths increase

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidcircuitry density

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The lead structure transitions from a two-dimensional planar arrangement to a three-dimensional configuration with vertical tiers. The first tier section connects to the bottom component assembly while the second tier section connects to the top component assembly, utilizing vertical space to accommodate multiple chips without increasing package footprint.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The lead is divided into distinct functional sections: a first tip for external connection, a connect area for component attachment, first and second tier sections for different connection levels, and a second tip for encapsulation. This segmentation allows each section to serve its specific function optimally.

Inventive Principle:

Principle #1Segmentation

2Volume of moving object

If multiple chips are stacked vertically, then package size is reduced, but lead length to reach all chips increases

Engineering Contradiction:

Improvepackage sizeVSAvoidlead length

Core Design Contradiction:

Volume of moving objectVSLength of moving object

Solution Approach 1:

The lead structure utilizes vertical dimension with tiered sections at different heights. The first tier section is positioned to connect with the bottom component assembly while the second tier section is positioned to connect with the top component assembly, minimizing horizontal wire lengths across the package.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If leads are extended with downset extensions, then connection to lower chips is improved, but chip placement is restricted to the lower half

Engineering Contradiction:

Improveconnectivity flexibilityVSAvoidchip placement flexibility

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

Instead of extending leads horizontally with downset extensions, the invention utilizes vertical dimension by forming tiered sections at different heights within the package. The first tier section serves the bottom component assembly while the second tier section serves the top component assembly, enabling chip placement throughout the entire package volume.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Rather than extending leads downward to reach lower chips, the invention inverts the approach by creating upward-tiered sections that reach from the bottom toward the top of the package, allowing top component assemblies to be positioned over the connect area.

Inventive Principle:

Principle #13The other way round (Inversion)

4Productivity

If component assemblies are placed throughout the package, then circuitry density increases, but manufacturing complexity increases

Engineering Contradiction:

Improvecircuitry densityVSAvoidmanufacturing complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The lead is segmented into distinct functional sections (first tip, connect area, first tier section, second tier section, second tip) that can be formed in a systematic manner. This segmentation provides a clear manufacturing roadmap for assembling multiple component assemblies at different levels.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The tiered lead structure serves multiple functions: providing mechanical support for both top and bottom component assemblies, establishing electrical connections at different vertical levels, and enabling flexible chip placement throughout the package volume without requiring separate lead structures for each chip.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7919360B1Integrated circuit packaging system with circuitry stacking and method of manufacture thereof

Publication Date: 2011.04.05 STATS CHIPPAC LTD

AI summary

A method of manufacture of an integrated circuit packaging system includes: forming a lead to include a first tip at one end, a second tip on the end opposite from the first tip with a connect area between each end located above the first tip, and a first tier section or a second tier section located between the connect area and the second tip; connecting a bottom component assembly to the first tier section or the second tier section; connecting a top component assembly over the connect area; and applying an encapsulant over and under the connect area with the first tip exposed.