Wire Interconnect Structure Cutting for Uniform Bond Tail Control
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Solution Overview
Problem
Conventional wire bonding techniques suffer from inconsistency in wire interconnect structures, such as height and shape, and face challenges in managing space constraints, leading to potential interference between adjacent structures.
Innovation Solution
A method involving a wire bonding tool with a through hole and a tapered tip portion featuring a cutting edge, which partially severs the wire during the bonding process, allowing for improved control and consistency in forming wire interconnect structures by varying the wire diameter and using a cutting feature to create a precise cut in the wire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wire bonding techniques are used, then wire interconnect structures can be formed, but inconsistency in height and shape occurs
Solution Approach 1:
The patent applies parameter changes by modifying the wire bonding tool tip geometry (tapered angle, cutting edge configuration) and controlling wire parameters (diameter, material properties) to achieve consistent wire interconnect structures. The tapered tip portion with specific angles and the cutting edge design enable precise control over wire severing, producing uniform wire tails in height and shape across multiple bonds.
2Productivity
If conventional wire bonding techniques are used, then wire loops can be formed, but space constraints lead to interference between adjacent structures
Solution Approach 1:
The patent extracts the excess wire length by introducing a cutting feature that partially severs the wire during the bonding process. This creates wire interconnect structures with controlled, reduced wire tail lengths, eliminating the need for long wire loops and reducing the space occupied by each interconnect structure, thereby preventing interference between adjacent structures.
3Ease of operation
If conventional wire bonding techniques are used, then wire bonds can be formed, but lack of control over wire tail length occurs
Solution Approach 1:
The patent implements self-service by integrating the cutting function directly into the wire bonding tool tip. The cutting edge automatically severs the wire during the bonding operation itself, eliminating the need for separate wire cutting steps. This maintains operational simplicity while achieving precise wire tail length control through the geometric design of the tapered tip and cutting edge.
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 method enhances the consistency of wire interconnect structures in height and shape, increases production efficiency, and allows for more precise control over wire tail lengths, addressing the issues of inconsistency and space constraints in conventional techniques.
Implementation Method 1
In forming the bonds between (a) the ends of the wire loop and (b) the bond sites (e.g., die pads, leads, etc.), varying types of bonding energy may be used including, for example, ultrasonic energy
Implementation Method 2
In forming the bonds between (a) the ends of the wire loop and (b) the bond sites (e.g., die pads, leads, etc.), varying types of bonding energy may be used including, for example, ultrasonic energy, thermosonic energy
Implementation Method 3
In forming the bonds between (a) the ends of the wire loop and (b) the bond sites (e.g., die pads, leads, etc.), varying types of bonding energy may be used including, for example, ultrasonic energy, thermosonic energy, thermo-compressive energy
Data Source
AI summary
A method of forming a wire interconnect structure includes the steps of: (a) forming a wire bond at a bonding location on a substrate using a wire bonding tool; (b) extending a length of wire, continuous with the wire bond, to a position above the wire bond; (c) moving the wire bonding tool to contact the length of wire, at a position along the length of wire, to partially sever the length of wire at the position along the length of wire; and (d) separating the length of wire from a wire supply at the position along the length of wire, thereby providing a wire interconnect structure bonded to the bonding location.