Self-Aligned Contact Openings for Short-Resistant Semiconductor Contacts
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Solution Overview
Problem
The challenge in semiconductor manufacturing is forming contact features between adjacent conductive features without causing short circuits, as the reduced distance between them increases the likelihood of electrical shorts.
Innovation Solution
A method involving the formation of a void in a dielectric layer, allowing for the self-aligned creation of contact features beyond the limitations of patterning processes, using a void to align and fill contact holes with conductive material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the distance between adjacent conductive features is decreased to increase functional density, then production efficiency is improved and costs are lowered, but the possibility of shorting contact features significantly increases
Solution Approach 1:
The patent introduces a spacer layer that extends laterally beyond the conductive feature, creating a three-dimensional structure. This lateral extension in the horizontal dimension provides electrical isolation between adjacent contact features, resolving the shorting problem that arises when vertical scaling reduces the distance between conductive features.
Solution Approach 2:
The spacer layer acts as an intermediary structure between adjacent conductive features. It provides a physical and electrical barrier that prevents shorting while allowing the conductive features to be positioned closer together, thus enabling higher functional density without compromising reliability.
2Manufacturing precision
If the distance between contact features is decreased to match the decreased distance between conductive features, then functional density is increased, but manufacturing precision requirements become more challenging
Solution Approach 1:
The spacer layer is formed using a self-aligned process where the spacer material automatically positions itself relative to the conductive feature through conformal deposition. This self-alignment mechanism eliminates the need for additional lithography and patterning steps, significantly reducing manufacturing complexity while maintaining precise positioning of contact features.
Solution Approach 2:
The spacer layer is formed in advance before the contact holes are etched. This preliminary formation of the spacer structure provides a pre-defined template that guides subsequent processing steps, ensuring that contact features are correctly positioned and isolated before the actual contact hole formation begins.
Data Source
AI summary
A method of fabricating a semiconductor device includes recessing an upper portion of a first dielectric layer disposed over a conductive feature. The method includes filling the recessed upper portion with a second dielectric layer to form a void embedded in the second dielectric layer. The method includes etching the second dielectric layer and the first dielectric layer to form a contact opening that exposes at least a portion of the conductive feature using the void to vertically align at least a lower portion of the contact opening with the conductive feature. The method includes filling the contact opening with a conductive material to form a contact feature electrically coupled to the conductive feature.