Spacer-Aligned Interconnect Layout to Prevent Electrical Shorting
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Solution Overview
Problem
The challenge of forming high-density interconnect features in integrated circuits is exacerbated by increased scaling, leading to higher chances of electrical shorting between adjacent features due to unintended shifts during the formation process.
Innovation Solution
The use of spacers composed of a first dielectric material, which are etch selective to the interlayer dielectric material, to laterally separate interconnect features, preventing electrical shorting by maintaining a wider recess for precise masking and etching, and ensuring the spacers remain intact during the formation of subsequent recesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If interconnect features are scaled down to increase density, then productivity is improved, but manufacturing precision deteriorates due to increased risk of electrical shorting
Solution Approach 1:
A spacer layer is introduced as an intermediary structure between adjacent interconnect features. This spacer layer physically separates the features and maintains precise spacing during subsequent etching and fabrication processes, preventing electrical shorting while enabling higher density interconnect formation.
Solution Approach 2:
The spacer layer is formed in advance before the interconnect features are fully defined. This preliminary structure establishes the spacing boundaries early in the fabrication process, ensuring that subsequent etching and material deposition maintain the required precision even as features are scaled down.
2Productivity
If spacing between interconnect features is reduced to increase density, then productivity is improved, but reliability deteriorates due to increased electrical shorting risk
Solution Approach 1:
The spacer layer serves as a protective intermediary that maintains electrical isolation between closely spaced interconnect features. By physically separating the features and controlling the spacing, it enables high density while preventing electrical shorting, thus maintaining reliability.
Solution Approach 2:
The spacer layer provides a protective buffer zone between interconnect features before any potential electrical shorting can occur. This pre-established physical barrier compensates for the reduced spacing, ensuring that even with higher density, the electrical isolation is maintained throughout the fabrication and operation processes.
3Device complexity
If conventional etching processes are used without spacers, then device complexity is reduced, but manufacturing precision deteriorates due to unintended shifts during formation
Solution Approach 1:
The spacer layer acts as a reference structure that defines the boundaries for subsequent etching processes. By having this physical barrier in place, the etching process can be precisely controlled to stop at the spacer edges, preventing unintended shifts and ensuring accurate feature alignment even though the overall device complexity increases.
Solution Approach 2:
The spacer layer is formed as a preliminary structure that establishes the geometric constraints for subsequent processing steps. This pre-defined structure serves as a template that guides the etching and material deposition processes, ensuring that features are formed with the correct alignment and spacing without requiring complex real-time control mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the chances of electrical shorting by maintaining precise spacing and process margins, allowing for the formation of high-density interconnect features with improved reliability and reduced manufacturing defects.
Implementation Method 1
The use of spacers composed of a first dielectric material, which are etch selective to the interlayer dielectric material, to laterally separate interconnect features
Data Source
AI summary
An integrated circuit includes a first conductive structure, a second conductive structure, and a first spacer and a second spacer each comprising a first dielectric material. The integrated circuit further includes a layer comprising a second dielectric material that is compositionally different from the first dielectric material. The integrated circuit further includes a first interconnect feature above and at least partially landed on the first conductive structure. In an example, the first interconnect feature is laterally between the first spacer and the second spacer. The integrated circuit further includes a second interconnect feature above and at least partially landed on the second conductive structure. In an example, the second interconnect feature is laterally between the second spacer and the layer comprising the second dielectric material.