MIM Capacitor Interconnect Structure for Low Contact Resistance
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Solution Overview
Problem
Conventional semiconductor devices face challenges with high contact resistance and manufacturing instability due to small contact areas between vias and elements, and the need to form via holes that can lead to material etching and variations in contact resistance.
Innovation Solution
A semiconductor device design where a connecting portion is formed over the lower interconnect and the end portion of a conductive layer, in contact with the upper and side faces of the element, eliminating the need for via holes that penetrate through the element, thereby ensuring a larger contact area and stable manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If via holes are formed to penetrate through the element to connect upper and lower interconnects, then the connection between interconnects is achieved, but the contact area between via and element is small leading to high contact resistance
Solution Approach 1:
The connecting portion extends not only vertically but also horizontally along the side face of the conductive layer, transforming a one-dimensional via structure into a three-dimensional structure that contacts both the upper face and side face of the conductive layer, thereby increasing the contact area and reducing contact resistance
Solution Approach 2:
The connecting portion is divided into multiple contact regions: one contact region contacting the upper face of the conductive layer and another contact region contacting the side face of the conductive layer, allowing each region to contribute to the overall contact area and reduce contact resistance
2Ease of manufacture
If via holes penetrate through the element, then interconnect connection is achieved, but the element material is etched during via formation causing variations in contact resistance
Solution Approach 1:
The connecting portion is extracted from the element structure itself and formed as a separate conductive structure that contacts the element, eliminating the need to form via holes through the element and preventing etching of the element material
Solution Approach 2:
The connecting portion acts as an intermediary structure between the upper and lower interconnects, providing a stable connection point that does not require penetration through the element, thereby preventing element material etching and contact resistance variations
3Volume of moving object
If small via holes are used to connect interconnects, then the device structure is compact, but the contact area is insufficient leading to high contact resistance
Solution Approach 1:
The connecting portion utilizes the side face of the conductive layer to extend the contact area in the horizontal dimension while maintaining a compact vertical profile, allowing sufficient contact area without increasing the overall device footprint
Data Source
AI summary
A semiconductor device includes an upper interconnect, a lower interconnect, insulating layers interposed between the upper interconnect and the lower interconnect, a connecting portion that is formed in the insulating layers and connects the upper interconnect and the lower interconnect, and an element that is placed in one of the insulating layers and has a conductive layer connected to the connecting portion. The connecting portion is formed over the lower interconnect and the end portions of the conductive layer of the element, and is in contact with the upper face of the lower interconnect and the upper faces and side faces of the end portions of the conductive layer of the element.