Insulated Leadframe Tips for Large Die Integration

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Solution Overview

Problem

The integration of older, larger-footprint IC dies into smaller contemporary package configurations is hindered by the smaller size of modern leadframes, leading to size, design, and cost penalties due to the inability of modern packages to accommodate larger dies effectively.

Innovation Solution

The method involves electrically insulating the leadtips of leadfingers in leadframes using non-conductive materials, allowing older-style IC dies to be positioned and connected without direct electrical contact, thereby enabling their integration into smaller packages by creating space through notches and non-conductive support, facilitating stable wire bonding and encapsulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If smaller contemporary package configurations are used, then device size is reduced, but older larger-footprint IC dies cannot be accommodated effectively

Engineering Contradiction:

Improvepackage sizeVSAvoidcompatibility with older IC dies

Core Design Contradiction:

Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The leadframe is segmented into multiple leadfingers with electrically insulated leadtips, allowing the die to be supported at multiple discrete points rather than requiring continuous contact. This segmentation enables the die to be positioned on insulated leadtips while maintaining electrical connection through other means (wire bonds, solder bumps), resolving the conflict between small package size and compatibility with larger dies.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Electrically insulating material is introduced as an intermediary between the leadtips and the IC die. This intermediary layer prevents direct electrical contact while still allowing mechanical support and positioning of the die, enabling older larger dies to be mounted in smaller contemporary packages without electrical interference or short circuits.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If direct electrical contact is made between leadtips and IC die, then electrical connection is established, but positioning and support of larger dies is compromised

Engineering Contradiction:

Improveelectrical connectionVSAvoiddie positioning and support

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The electrical connection function is segmented from the mechanical support function. Leadtips are electrically insulated to provide mechanical support and positioning, while separate connection mechanisms (wire bonds, solder bumps) establish electrical connection. This functional segmentation resolves the contradiction between reliable electrical connection and ease of die positioning.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Electrically insulating material serves as an intermediary that decouples the electrical connection requirement from the mechanical support function. The insulating layer on leadtips provides mechanical support and positioning without creating unwanted electrical contact, while electrical connection is established through dedicated bonding interfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7700404B2Large die package structures and fabrication method therefor

Publication Date: 2010.04.20 STATS CHIPPAC LTD

AI summary

A method for fabricating large die package structures is provided wherein at least portions of the leadtips of at least a plurality of leadfingers of a leadframe are electrically insulated. A die is positioned on the electrically insulated leadtips. The die is electrically connected to at least a plurality of the leadfingers.