IC Package Wire Bond Layout Using a Connecting Tie Bar

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Solution Overview

Problem

Existing integrated circuit (IC) packages face challenges with wire bond failures due to contact with epoxy bleed-out during the mounting process, which can lead to increased likelihood of failure and reduced die pad utilization.

Innovation Solution

Incorporating a wire bond that connects the die to a connecting tie bar, avoiding direct contact with the die pad and epoxy bleed-out, thereby providing a reliable current path and allowing for larger die sizing without increasing failure risk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wire bonds are attached directly to the die pad, then the current path is established, but the wire bonds contact with epoxy bleed-out causing increased likelihood of failure

Engineering Contradiction:

Improvewire bond reliabilityVSAvoidepoxy bleed-out contact

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A connecting tie bar is introduced as an intermediary element between the die pad and the wire bond. The tie bar extends from the die pad and provides a dedicated bonding surface for the wire bond, preventing direct contact between the wire bond and epoxy bleed-out. This intermediary structure isolates the wire bond from the harmful epoxy while maintaining the current path functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If die pad area is increased to accommodate wire bonds, then wire bond placement is facilitated, but the die pad utilization efficiency decreases

Engineering Contradiction:

Improvewire bond placementVSAvoiddie pad area

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The die pad structure is segmented into two functional zones: the die pad area for mounting the die, and the connecting tie bar extending from it for wire bond attachment. This segmentation allows the wire bond to be attached to the tie bar rather than requiring additional space on the die pad itself, thereby maintaining die pad utilization efficiency while facilitating wire bond placement.

Inventive Principle:

Principle #1Segmentation

3Area of stationary object

If wire bonds are positioned closer to die edges, then die pad area utilization is improved, but the risk of wire bond failure increases

Engineering Contradiction:

Improvedie pad area utilizationVSAvoidwire bond failure risk

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The connecting tie bar serves as a mediator that decouples the wire bond position from the die pad boundaries. By extending the tie bar toward the die edges and attaching the wire bond to the tie bar rather than directly to the die pad, the design enables closer positioning to die edges for better area utilization while the tie bar protects the wire bond from failure risks associated with edge proximity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20240162121A1Integrated circuit package with wire bond

Publication Date: 2024.05.16 TEXAS INSTRUMENTS INC

AI summary

An integrated circuit (IC) package includes an interconnect. The interconnect has a connecting tie bar and a die pad. The IC package also includes a die mounted on the die pad of the interconnect. The IC package further includes a wire bond coupled to the die and the connecting tie bar to provide a current path between the die and the connecting tie bar.