Leadframe Spacer Structure for Thin-Lead Wire Bonding Support

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Solution Overview

Problem

Semiconductor manufacturing processes often compromise between cost reduction and performance/reliability, with existing technologies failing to adequately support leadframe structures during wire bonding operations, leading to reduced yields and reliability.

Innovation Solution

A semiconductor device with a leadframe spacer structure, where a non-conductive, rigid spacer is attached to the inner portion of half-etched leads using an adhesive, providing reinforcement and support during manufacturing, particularly during wire bonding, by ensuring the bottom surfaces of the leads and spacer are coplanar and exposed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If the leads are made thinner to reduce material usage and cost, then manufacturing cost is reduced, but the leads become weaker and more prone to damage during wire bonding operations

Engineering Contradiction:
Improvematerial usageVSAvoidlead strength
Core Design Contradiction:
Loss of substanceVSStrength

Solution Approach 1:

The patent applies composite materials by combining the metal lead with a non-conductive spacer material to form a composite structure. The spacer is integrated with the lead to create a reinforced composite that maintains mechanical strength while allowing the metal portion to remain thin, thus reducing material usage while preventing lead damage during wire bonding operations

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The non-conductive spacer acts as an intermediary element that supports the thin metal lead during manufacturing operations. The spacer provides the necessary mechanical strength and support during wire bonding without interfering with the electrical function of the lead, effectively mediating between the need for thin leads and the need for structural strength

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If conventional manufacturing processes are used without spacer structures, then device complexity is reduced, but lead damage during wire bonding increases resulting in lower yields

Engineering Contradiction:
Improvemanufacturing yieldVSAvoidstructure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The spacer structure is attached to the leads in advance, before the wire bonding operation takes place. This preliminary action of reinforcing the leads with spacers ensures that the leads are protected during subsequent manufacturing steps, preventing damage and improving manufacturing yield without requiring complex modifications during the wire bonding process itself

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances the reliability and yield of semiconductor devices by reinforcing the leads during manufacturing operations, such as wire bonding, resulting in improved overall performance and reliability.

Implementation Method 1

The spacer structure is attached at a bottom side of the inner portion of the leads by way of an adhesive material

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP4485529A1Semiconductor device with leadframe spacer and method therefor
Publication Date: 2025.01.01 NXP BV
  • EP4485529A1 patent drawingFigure 1
  • EP4485529A1 patent drawingFigure 2
  • EP4485529A1 patent drawingFigure 3

AI summary

A method of manufacturing a semiconductor device is provided. The method includes affixing a spacer structure to a bottom side of a plurality of leads of a leadframe. A semiconductor die is attached to a top side of a die pad of the leadframe. The semiconductor die, the leadframe, and the spacer structure are encapsulated with an encapsulant. Portions of the spacer structure and portions of the leads of the plurality of leads are exposed at a bottom side of the encapsulant.