Insulated Bond Wire Brace for Multi-Tier Semiconductor Devices

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Solution Overview

Problem

Semiconductor devices with multiple tiers of bond wires often experience wire sagging and shorting issues due to the length and loop height differences of the wires, particularly when there is only one row of leads, leading to potential electrical failures.

Innovation Solution

Incorporating an insulated bond wire as a brace between the tiers of bond wires, extending from dummy leads or pads to prevent sagging and contact between the longer and shorter bond wires, thereby maintaining electrical connectivity and preventing short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple tiers of bond wires are used to connect bond pads to leads, then the electrical connectivity is improved, but wire sagging and shorting occur due to wire length differences

Engineering Contradiction:

Improveelectrical connectivityVSAvoidwire sagging and shorting

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An insulated wire is introduced as an intermediary element between the first and second sets of bond wires. This insulated wire acts as a brace that prevents the longer second set of bond wires from sagging and contacting the first set of bond wires, thereby eliminating shorting while maintaining electrical connectivity through the multiple tiers of wires.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Length of moving object

If longer bond wires are used to extend from in-board bond pads to outer leads, then the connectivity range is improved, but wire sagging increases

Engineering Contradiction:

Improvebond wire lengthVSAvoidwire stability

Core Design Contradiction:

Length of moving objectVSStability of the object's composition

Solution Approach 1:

The insulated wire serves as a supporting intermediary that spans between dummy leads and provides mechanical support to the longer second set of bond wires. This prevents excessive sagging and maintains wire stability while allowing the necessary wire length to reach from in-board bond pads to outer leads.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulated wire is positioned in advance to counteract the gravitational force that causes wire sagging. By establishing this supporting structure before the wire sags occur, the system prevents the harmful effect of sagging rather than correcting it after it happens.

Inventive Principle:

Principle #9Preliminary anti-action

3Device complexity

If only one row of leads is used, then the device complexity is reduced, but wire shorting becomes more problematic

Engineering Contradiction:

Improvelead structureVSAvoidwire shorting risk

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

When only one row of leads is used, the insulated wire becomes critical as an intermediary separator between the first and second sets of bond wires. It physically separates wires that would otherwise converge on the same lead, preventing shorting while maintaining the simplified single-row lead structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8680660B1Brace for bond wire

Publication Date: 2014.03.25 NXP USA INC

AI summary

In a semiconductor device having multiple tiers of bond wires extending in a first direction, dummy insulated bond wires extend in a second direction orthogonal to the first direction and between the wire tiers to support the wires in an upper tier to prevent them from sagging and contacting wires in a lower tier.