Via Contact Resistance Control via Opposite Gouging
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Solution Overview
Problem
The challenge in semiconductor circuits is to improve via contact conductivity without damaging the dielectric surface, as conventional via gouging processes increase contact resistance but degrade the dielectric and metallurgy layers, affecting interconnect reliability.
Innovation Solution
Creating an 'opposite gouging feature' in the metal line with a protuberant, convex shape that increases the contact area for via connectors, formed using a non-perpendicular sputtering process, which enhances conductance without damaging the dielectric surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If via gouging process is used to improve contact resistance, then contact area between via and metal line is increased, but dielectric surface is damaged and metallurgy layers are degraded
Solution Approach 1:
Instead of removing material from the metal line to create a gouge (conventional approach), the invention inverts the approach by depositing additional metal material to create a protuberant feature that extends upward. This opposite approach achieves increased contact area without the harmful side effects of material removal and dielectric damage
Solution Approach 2:
The invention changes the parameter of metal line topology from flat to protuberant by controlling the sputtering deposition angle. By using non-perpendicular sputtering at specific angles, the metal deposits in a way that creates upward-extending features, transforming the contact geometry to improve contact resistance without damaging surrounding structures
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 approach improves the conductance of the via-to-metal line interface and overall interconnect structure reliability by increasing the contact area while minimizing damage to the dielectric and metallurgy layers.
Implementation Method 1
the plasma sputtering typically used to produce the feature
Data Source
AI summary
A first dielectric layer on a substrate is provided. The first dielectric layer has a first level metal line embedded in the dielectric. An opposite gouging feature is created in a top surface of the first level metal line. The opposite gouging feature has a protuberant shape relative to the first level metal line. A second dielectric layer is formed over the first dielectric layer. A compound recess is formed in the second dielectric layer. A first portion of the recess is for a via connector positioned over the opposite gouging feature. A second portion of the recess for a second level metal line. In another aspect of the invention, a device is produced using the method.