SiCr Ring Resistor Structure for Low-TCR Chip Reliability
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Solution Overview
Problem
Polysilicon resistors in integrated chips face issues such as high temperature coefficient of resistance (TCR) leading to resistance changes over time, especially in high voltage applications, resulting in device failure due to high heat accumulation and low breakdown voltage.
Innovation Solution
A resistor structure using silicon chromium (SiCr) with a reduced TCR, fabricated using a method that reduces the number of patterning processes, including forming a resistive layer, conductive contact layer, and dielectric structure, with ring structures that laterally enclose and isolate resistor segments, concurrently forming conductive vias and ring structures to simplify fabrication and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polysilicon resistors are used in integrated chips, then fabrication is simpler, but temperature coefficient of resistance increases leading to resistance changes over time
Solution Approach 1:
The patent changes the material parameter from polysilicon to silicon chromium (SiCr) to achieve a lower temperature coefficient of resistance. This material substitution directly addresses the resistance stability issue while maintaining compatibility with standard semiconductor fabrication processes, thus resolving the contradiction between ease of manufacture and reliability.
2Device complexity
If polysilicon resistors are used in high voltage applications, then device complexity is reduced, but heat accumulation increases causing device failure
Solution Approach 1:
The patent employs silicon chromium (SiCr) as a composite material that combines the benefits of low temperature coefficient of resistance with improved thermal management properties. This composite material approach allows the resistor to handle high voltage applications better by reducing heat accumulation while maintaining structural simplicity.
3Manufacturing precision
If conventional patterning processes are used for resistor fabrication, then manufacturing precision is maintained, but fabrication time and complexity increase
Solution Approach 1:
The patent merges the formation of conductive vias and ring structures into a single fabrication step. By combining these previously separate patterning processes into one concurrent operation, the patent reduces fabrication time and complexity while maintaining the required manufacturing precision for resistor structures.
Data Source
AI summary
Various embodiments of the present disclosure are directed towards a method for forming an integrated chip. The method includes depositing a resistive layer over a substrate. A conductive structure is formed over the resistive layer. A first etch process is performed on the resistive layer to define a resistor segment of the resistive layer and a peripheral region of the resistive layer. The resistor segment is laterally separated from the peripheral region of the resistive layer. The peripheral region continuously laterally wraps around an outer perimeter of the resistor segment.