Titanium Nitride Interlayer for Crack Prevention in Semiconductor Wire Bonding
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Solution Overview
Problem
Conventional semiconductor devices face issues with cracks occurring under bonding pads due to ultrasonic wave intensity during wire joining, leading to potential short circuits and reduced reliability.
Innovation Solution
A semiconductor device design featuring a titanium nitride layer with a thickness of 800 Å or more between the pad metal and lower layer wiring pattern, which prevents cracks by distributing ultrasonic energy effectively and using copper bonding wires for improved conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ultrasonic waves are applied to join wire to bonding pad, then wire joining is achieved, but cracks occur under the bonding pad leading to short circuits
Solution Approach 1:
A titanium nitride layer with a thickness of 800 Å or more is introduced as an intermediary between the pad metal and the lower layer wiring pattern. This intermediate layer absorbs and distributes the ultrasonic energy during wire joining, preventing direct transmission of mechanical stress to the wiring pattern and thereby preventing cracks while maintaining effective wire bonding.
2Productivity
If region directly under bonding pad is utilized for wiring, then wiring space is effectively used, but crack susceptibility increases
Solution Approach 1:
The titanium nitride layer serves as a protective intermediary that enables the placement of wiring directly under the bonding pad by absorbing ultrasonic energy. This allows effective utilization of the region under the bonding pad for wiring purposes while the titanium nitride layer prevents crack propagation to the wiring, thus maintaining both high wiring space utilization and reliability.
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 solution effectively prevents cracks under the pad metal, enhancing the reliability of semiconductor devices and allowing the use of copper bonding wires for efficient electrical conduction, replacing gold wires.
Implementation Method 1
Depending on the intensity of ultrasonic waves on joining a wire to the bonding pad, a crack may appear in the vicinity of the bonding pad... the titanium nitride layer having the thickness of 800 Å or more, and a pad metal disposed on the titanium nitride layer
Data Source
AI summary
The semiconductor device of the present invention includes a semiconductor substrate provided with semiconductor elements, a lower layer wiring pattern which includes first wiring and second wiring, the first wiring and the second wiring disposed separately so as to be flush with each other, and the first wiring and the second wiring being fixed at a mutually different potential, an uppermost interlayer film disposed on the lower layer wiring pattern, a titanium nitride layer disposed on the uppermost interlayer film so as to cover the first wiring and the second wiring, and the titanium nitride having the thickness of 800 Å or more, and a pad metal disposed on the titanium nitride layer.