Integrated Thin Film Resistor With Buffer Contact Sidewalls
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Solution Overview
Problem
Existing thin film resistors in semiconductor systems face misalignment and punch-through issues during etching processes, leading to alignment and contact resistance problems when integrated with metal-insulator-metal capacitors.
Innovation Solution
The integration of a thin film resistor structure with buffer contacts on the same wiring level as the capacitor plates, where the resistive film contacts the sidewalls of these buffer contacts, avoiding direct contact with electrical contacts to prevent punch-through and extending the contact area, thereby reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photolithography and etching processes are used to form electrical contacts to the resistive film, then electrical contact can be established, but misalignment and punch-through issues occur leading to alignment problems and increased contact resistance
Solution Approach 1:
The patent introduces an intermediary structure (the resistive film itself configured to wrap around the buffer contact) between the buffer contact and the electrical contact. This intermediary design allows the electrical contact to land on the buffer contact without directly etching through the resistive film, thereby preventing punch-through while ensuring reliable electrical connection. The resistive film wraps around the buffer contact to provide both mechanical support and electrical pathway.
Solution Approach 2:
The buffer contact is formed preliminary before the electrical contact formation step. The buffer contact serves as a pre-established landing area that guides the subsequent electrical contact formation process, ensuring proper alignment without requiring high-precision etching. This preliminary structure prevents misalignment issues by providing a robust target for the electrical contact.
2Reliability
If electrical contacts directly contact the resistive film to establish electrical connection, then contact resistance can be reduced, but punch-through of the resistive layer occurs during etching
Solution Approach 1:
The buffer contact acts as an intermediary element that the electrical contact lands on instead of directly etching through the resistive film. The resistive film is configured to wrap around the buffer contact, creating a structure where the electrical contact establishes connection through the buffer contact while the resistive film provides a protective barrier that prevents etching punch-through.
Solution Approach 2:
The buffer contact serves as a cushioning structure formed beforehand to absorb the mechanical and chemical stress of the etching process. By providing this preliminary protective layer, the design prevents direct exposure of the resistive film to the etching process, thereby preventing punch-through defects while maintaining electrical connectivity.
3Area of stationary object
If the resistive film contact area with electrical contacts is minimized, then device area is reduced, but contact resistance increases
Solution Approach 1:
The resistive film is configured to wrap around the buffer contact in a three-dimensional manner, extending along the sidewalls of the buffer contact. This dimensional transformation from a planar contact to a wraparound contact increases the effective contact area without significantly increasing the planar footprint of the device. The wraparound configuration provides multiple contact paths, reducing contact resistance while maintaining compact device area.
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to an integrated thin film resistor with a metal-insulator-metal capacitor and methods of manufacture. The structure includes: a first buffer contact on a substrate; a second buffer contact on the substrate, the second buffer contact being on a same wiring level as the first buffer contact; a resistive film contacting the first buffer contact and the second buffer contact, the resistive film extending on the substrate between the first buffer contact and the second buffer contact; and electrical contacts landing on both the first buffer contact and the second buffer contact, but not directly contacting with the resistive film.