Bottom Conductive Structure With Dielectric Spacer Contact Limit
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Solution Overview
Problem
Conventional subtractive metal patterning schemes face challenges in achieving dielectric material fill without voids or seams in patterned metal features and in forming a top contact structure with a sufficient process window, especially as metal pitch decreases.
Innovation Solution
A dielectric spacer is formed laterally adjacent to a bottom conductive structure to limit the contact area for a top contact structure, which can contact the topmost surface and upper sidewall surfaces of the bottom conductive structure, ensuring precise and void-free interconnects and memory structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional subtractive metal patterning is used to reduce metal pitch, then resistance benefits are improved, but dielectric material fill without voids or seams becomes challenging
Solution Approach 1:
The patent applies preliminary action by forming the dielectric spacer structure before the top contact structure is deposited. The spacer is formed laterally adjacent to the bottom conductive structure, establishing a predefined contact area limitation that guides subsequent material deposition and prevents void formation in the dielectric fill.
Solution Approach 2:
The dielectric spacer acts as an intermediary element between the bottom conductive structure and the top contact structure. It mediates the contact interface by providing a controlled lateral boundary that ensures proper dielectric material fill while maintaining the electrical connection through the defined contact area.
2Device complexity
If conventional subtractive metal patterning is used, then no metal liner is needed, but the process window for forming a top contact structure becomes challenging
Solution Approach 1:
The dielectric spacer is formed in advance as a preliminary structure that defines the contact area boundaries before top contact deposition. This preliminary action establishes clear process windows by providing a physical template that guides the formation of the top contact structure, making the manufacturing process more controllable despite the reduced metal liner approach.
3Reliability
If the top contact structure contacts a limited area of the bottom conductive structure, then void-free interconnects are achieved, but manufacturing precision requirements increase
Solution Approach 1:
The dielectric spacer serves as a precise intermediary that defines the contact area boundaries. It mediates between the manufacturing process and the final contact structure by providing a physical template that ensures the top contact structure contacts only the intended limited area of the bottom conductive structure, achieving both reliability and precision.
Solution Approach 2:
The invention applies local quality by creating a spatially differentiated structure where the dielectric spacer provides localized contact area limitation. The spacer is positioned specifically laterally adjacent to the bottom conductive structure, creating a defined zone that controls the contact interface locally while allowing other areas to maintain their structural integrity.
Data Source
AI summary
A dielectric spacer is formed laterally adjacent to a bottom conductive structure. The dielectric spacer is configured to limit the area in which a subsequently formed top contact structure can contact the bottom conductive structure. In some embodiments, only a topmost surface of the bottom conductive structure is contacted by the top contact structure. In other embodiments, a topmost surface and an upper sidewall surface of the bottom conductive structure is contacted by the top contact structure.