Semiconductor Contact Pad Protrusion for Reduced Resistance
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Solution Overview
Problem
As semiconductor devices become more highly integrated, the reduced size of contact pads increases contact resistance and reduces the align margin between the contact pad and the capacitor's lower electrode, leading to inefficiencies in electrical connections.
Innovation Solution
The implementation of a semiconductor device design that includes an insulation interlayer, an etch stop layer, and a pad spacer, where the second contact pad protrudes from the etch stop layer and is connected to a lower electrode, which surrounds the upper portion of the contact pad, thereby increasing the contact area and reducing resistance, and a landing pad with a greater cross-sectional area to ensure proper alignment and prevent shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the contact pad size is reduced to achieve higher integration, then the device density increases, but the contact resistance between the contact pad and lower electrode increases significantly
Solution Approach 1:
The contact pad structure transitions from a planar 2D configuration to a 3D protruding structure that extends vertically from the etch stop layer. This dimensional change allows the contact pad to maintain a smaller footprint area while increasing its effective contact surface area through vertical extension, thereby reducing contact resistance without sacrificing integration density
Solution Approach 2:
The lower electrode is designed to surround the protruding upper portion of the contact pad, creating a nested configuration where the electrode envelops the contact pad structure. This nesting increases the contact interface area between the electrode and contact pad, effectively reducing contact resistance while maintaining compact device dimensions
2Productivity
If the contact pad size is reduced to achieve higher integration, then the device density increases, but the align margin between the contact pad and lower electrode decreases
Solution Approach 1:
By extending the contact pad vertically in the third dimension, the design decouples the horizontal alignment requirements from the vertical contact formation. The protruding structure provides a larger vertical target area for the lower electrode to contact, increasing the effective align margin in the vertical direction while maintaining small horizontal footprint for high integration
Solution Approach 2:
The lower electrode surrounds the protruding contact pad in a nested arrangement, which provides inherent alignment tolerance. The enveloping structure ensures that as long as the electrode partially overlaps the contact pad vertically, electrical connection is achieved, thereby increasing the effective align margin and reducing sensitivity to lateral alignment variations
3Productivity
If the contact pad size is reduced, then the device integration increases, but the risk of short circuits between the contact pad and surrounding structures increases
Solution Approach 1:
The pad spacer is introduced as an intermediary insulating structure positioned between the protruding contact pad and the insulation interlayer. This spacer maintains an appropriate gap that prevents direct contact between conductive elements, eliminating short circuit risk while allowing the contact pad to protrude for improved electrical connection
Solution Approach 2:
The harmful effect of potential short circuits is addressed by extracting the insulation function into a separate dedicated component (the pad spacer). This spacer is specifically designed to provide electrical isolation between the contact pad and surrounding conductive structures, allowing the contact pad to be optimized for low resistance without compromising device reliability
Data Source
AI summary
A semiconductor device includes an insulation interlayer and an etch stop layer sequentially stacked on a substrate wherein a lower structure including a first contact pad is formed. A second contact pad penetrates the insulation interlayer and the etch stop layer and is connected to the first contact pad. The second contact pad protrudes from the etch stop layer. A pad spacer is provided between the second contact pad and the insulation interlayer. A lower electrode is provided on the etch stop layer and is connected to the second contact pad. A dielectric layer and an upper electrode are sequentially provided on the lower electrode.