CPODE Fin Etching for Leakage Path Isolation
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Solution Overview
Problem
Integrated circuits face challenges in reducing leakage current through continuous poly on diffusion edge (CPODE) structures due to difficulties in controlling etching between closely spaced fins, leading to extra material that forms a leakage path and increases parasitic capacitance.
Innovation Solution
A method involving the formation of a CPODE structure by etching away fins and forming trenches in the substrate using alternating etchants to remove extra material, followed by filling these trenches with a dielectric material to isolate neighboring active device regions, thereby reducing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If alternating etchants are used to remove extra material between fins, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The etching process is segmented into multiple alternating steps using different etchants. The first etchant selectively removes material from specific regions while the second etchant removes material from other regions, allowing precise control over the etching between closely spaced fins without requiring complex single-step processes
Solution Approach 2:
The patent employs periodic alternating etching cycles where the first etchant and second etchant are applied in repeated sequences. This periodic action enables progressive removal of extra material between fins while maintaining control over the etching depth and pattern, improving manufacturing precision through iterative refinement
2Object-generated harmful factors
If trenches are formed to remove extra material, then leakage current is reduced, but processing time increases
Solution Approach 1:
Trenches are formed in advance before final device assembly to pre-remove extra material between fins. This preliminary action eliminates the formation of leakage paths early in the manufacturing process, preventing leakage current issues before they affect device performance and reducing the need for subsequent corrective processing steps
Solution Approach 2:
The patent extracts and removes the harmful extra material between fins by forming trenches that selectively eliminate this material. By taking out the problematic regions that would create leakage paths, the device achieves better electrical isolation and reduced leakage current without requiring complex post-processing
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
The method effectively reduces leakage current and parasitic capacitance by eliminating the conductive channel between fins, enhancing processing speed and electrical isolation.
Implementation Method 1
A first etch is performed with a first etchant to etch away exposed portions of a pair of fins located on opposite sides of a leakage path. A second etch is performed with plasma to remove any byproducts of the first etch. Cycling between the first etch and the second etch continues until a pair of trenches is formed in a substrate
Data Source
AI summary
Methods for forming a CPODE structure with reduced leakage current are disclosed herein. The CPODE structure is formed by etching away a pair of fins and forming a pair of trenches in the substrate where the pair of fins was originally located. A leakage path may be present in the area between the pair of fins. The etching is performed by cycling continuously plasma etch until the trenches are formed. The plasma etch removes any byproducts that may be formed during the fin etch which could reduce or stop the etching of the fins, the area between the pair of fins, and the substrate.