Programmable Resistive Element for Integrated Circuit Trimming
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Solution Overview
Problem
Existing resistor trimming methods in semiconductor integrated circuits face challenges such as large polysilicon resistors, difficulty in scaling down transistor size, and the need for separate non-volatile memory to store trim information, which complicates the tuning process and increases complexity.
Innovation Solution
The use of programmable resistive elements formed during the back-end-of-line (BEOL) process, which are small, can stack over front-end-of-line (FEOL) devices, store trim information non-volatilely, and adjust electrical characteristics without requiring additional memory, allowing for precise tuning of voltage or current reference generation circuits and mismatch cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polysilicon resistors are used for trimming, then resistance tuning can be achieved, but the resistors become large and transistor size cannot be scaled down
Solution Approach 1:
The patent combines the trimming function with the interconnect structure by forming programmable resistive elements directly in the BEOL wiring layers. This merging eliminates the need for separate large polysilicon resistors while maintaining trimming capability, as the programmable resistive elements are integrated into the existing interconnect path.
Solution Approach 2:
The patent transitions from planar trimming elements to three-dimensional stacked structures. By forming programmable resistive elements in vertical stacks within the BEOL layers, the solution achieves high-density integration and scaling while maintaining precise resistance control through programmable states.
2Reliability
If separate non-volatile memory is used to store trim information, then trim settings can be retained, but device complexity increases
Solution Approach 1:
The patent merges the trim storage function directly into the interconnect structure by using programmable resistive elements that inherently retain their programmed resistance states. This eliminates the need for separate non-volatile memory circuits while ensuring trim information is preserved through the non-volatile nature of the resistive elements themselves.
Solution Approach 2:
The programmable resistive elements serve dual functions: they provide the trimming capability and simultaneously store the trim information non-volatily. Each resistive element is self-sufficient, requiring no external memory support, which simplifies the overall device architecture.
3Manufacturing precision
If large polysilicon resistors are used, then resistance tuning is achievable, but transistor size must be larger to maintain matching
Solution Approach 1:
The patent changes the fundamental parameter of resistance implementation from fixed polysilicon resistor values to programmable resistive states. This allows precise resistance control and matching to be achieved through programming rather than physical dimension scaling, enabling transistor size reduction while maintaining matching precision.
Solution Approach 2:
The patent replaces the mechanical/physical approach of using large polysilicon resistors with electrical programming of resistive states. Instead of relying on physical resistor size for precision, the solution uses programmable resistance values, substituting physical scaling with electrical control.
Data Source
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AI summary
The present disclosure provides circuit and method embodiments for calibrating a signal of an integrated circuit. A programmable resistive element (110) is coupled in series with a node of the integrated circuit, where at least part of the integrated circuit is formed in at least one front end of line (FEOL) device level. The programmable resistive element (110) is formed in at least one back end of line (BEOL) wiring level, and the programmable resistive element is in a non-volatile resistive state that is variable across a plurality of non-volatile resistive states in response to a program signal applied to the programmable resistive element.