Wedge Bonding Tool Groove Geometry for Stable Wire Stacking

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing wedge bonding tools lack the necessary features to ensure stable stacking of wire bonds, which affects the electrical cross-sectional area and maximum current carried by the wire bond.

Innovation Solution

The wedge bonding tool features a tip portion with two opposing walls and an adjoining surface that includes a flat area or a convex portion, defining a groove configured to receive a wire. The flat area has a width of at least 20% of the groove's width at the working end, providing a stable surface for stacking wire bonds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional wedge bonding tools without groove modifications are used, then the structure is simple, but the stability and reliability of stacked wire bonds is insufficient

Engineering Contradiction:

Improvestability of stacked wire bondsVSAvoidcomplexity of wedge bonding tool structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by introducing specific geometric features (flat areas, protrusions, recesses) only at the groove bottom of the wedge bonding tool tip, while keeping the rest of the tool structure conventional. This localized modification improves wire bond stability without significantly increasing overall device complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The groove bottom is segmented into multiple functional zones including flat areas, protrusions, and recesses. Each segment serves a specific function in wire positioning and bonding stability, allowing the tool to handle complex bonding requirements through divided functional regions rather than a single uniform structure.

Inventive Principle:

Principle #1Segmentation

2Reliability

If wire size or bond pad dimensions are increased, then electrical cross-sectional area and current carrying capacity increase, but the device dimensions and complexity increase

Engineering Contradiction:

Improveelectrical cross-sectional area and current carrying capacityVSAvoidwire size and bond pad dimensions

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent changes the geometric parameters of the groove (flat area width, protrusion height, recess depth) to optimize wire bonding characteristics. These parameter adjustments improve electrical cross-sectional area and current carrying capacity through better wire configuration and contact, without requiring larger wire diameters or bond pad dimensions.

Inventive Principle:

Principle #35Parameter changes

3Force

If the groove width at the working end is reduced, then better wire grip is achieved, but the flat area width must be sufficiently large for stability

Engineering Contradiction:

Improvewire grip strengthVSAvoidflat area width

Core Design Contradiction:

ForceVSArea of moving object

Solution Approach 1:

The groove exhibits asymmetric geometry where the overall groove width is narrow for strong wire grip, but the flat area at the groove bottom has sufficient width for stability. This asymmetric design allows the groove walls to provide gripping force while the flat bottom area provides a stable base, resolving the contradiction between grip strength and stability area.

Inventive Principle:

Principle #4Asymmetry

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

The improved wedge bonding tool enhances the stability of stacked wire bonds, allowing for increased electrical cross-sectional area without requiring larger wire sizes, different materials, or larger bond pad sizes.

Implementation Method 1

The primary methods of forming wire bonds are ball bonding and wedge bonding. In forming wire bonds between (a) the ends of the wire loop and (b) the bond site (e.g., a die pad, a lead, etc.) varying types of bonding energy may be used, including, for example, ultrasonic energy

Methodology Applied

Scientific EffectUltrasonic energy: Ultrasonic Vibration

Implementation Method 2

varying types of bonding energy may be used, including, for example, ultrasonic energy, thermosonic energy

Methodology Applied

Scientific EffectThermosonic energy:

Implementation Method 3

varying types of bonding energy may be used, including, for example, ultrasonic energy, thermosonic energy, thermocompressive energy

Methodology Applied

Scientific EffectThermocompressive energy:

Data Source

PatentUS20250125303A1Wedge bonding tools and methods of forming wire bonds

Publication Date: 2025.04.17 KULICKE & SOFFA IND INC

AI summary

A wedge bonding tool is provided. The wedge bonding tool includes a body portion including a tip portion, the tip portion terminating at a working end of the wedge bonding tool. The tip portion includes (i) two opposing walls, and (ii) an adjoining surface between the two opposing walls. The adjoining surface includes a flat area. The two opposing walls and the flat area define a groove configured to receive a wire. The flat area has a width of at least 20% of a width of the groove at the working end.