Gate Isolation Structure for Critical Dimension Control
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Solution Overview
Problem
The semiconductor industry faces challenges in reducing device size and improving performance while minimizing defects, particularly in forming isolation structures for gate electrodes and semiconductor devices, due to limitations in controlling critical dimensions and managing scum production during etching processes.
Innovation Solution
The method involves forming a conformal layer over a gate structure using atomic layer deposition (ALD) or plasma-enhanced ALD, which narrows the opening and provides better control over critical dimensions, and using materials with high or low etch selectivity to the gate structure to reduce defects and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used to form isolation structures, then processing speed is maintained, but critical dimension control deteriorates and scum production increases
Solution Approach 1:
A conformal layer is deposited over the gate structure before the etching process to pre-narrow the opening. This preliminary action allows the subsequent etch to achieve better critical dimension control without requiring excessive etching time, thus resolving the contradiction between precision and productivity.
Solution Approach 2:
The conformal layer acts as an intermediary element that modifies the opening geometry before the etch process. By introducing this intermediate structure, the etching process can proceed more efficiently with improved dimension control and reduced scum production, balancing both precision and productivity requirements.
2Manufacturing precision
If conformal layer is deposited to narrow the opening, then critical dimension control improves, but device complexity increases
Solution Approach 1:
The conformal layer serves multiple functions: it narrows the opening for better critical dimension control, acts as a protective layer during etching, and reduces scum production. By combining multiple functions into a single layer, the process complexity increase is minimized while achieving significant precision improvements.
3Manufacturing precision
If materials with high etch selectivity are used, then manufacturing precision improves, but material selection and process complexity increase
Solution Approach 1:
The invention changes the material parameter of the conformal layer to have high etch selectivity relative to the gate structure. This parameter change enables precise control of the opening geometry while the selected materials (such as silicon nitride or silicon oxide) are standard semiconductor materials that do not significantly complicate the manufacturing process.
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 device defects, improves performance, and allows for smaller feature sizes by controlling critical dimensions and minimizing scum production, thereby enhancing the integration density of electronic components.
Implementation Method 1
forming a conformal layer over the gate structure using atomic layer deposition (ALD) or plasma-enhanced ALD
Implementation Method 2
forming a conformal layer over the gate structure using atomic layer deposition (ALD) or plasma-enhanced ALD
Data Source
AI summary
Improved methods for forming gate isolation structures between portions of gate electrodes and semiconductor devices formed by the same are disclosed. In an embodiment, a method includes forming a channel structure over a substrate; forming a first isolation structure extending in a direction parallel to the channel structure; forming a dummy gate structure over the channel structure and the first isolation structure; depositing a hard mask layer over the dummy gate structure; etching the hard mask layer to form a first opening through the hard mask layer over the first isolation structure; conformally depositing a first dielectric layer over the hard mask layer, in the first opening, and over the dummy gate structure; etching the first dielectric layer to extend the first opening and expose the dummy gate structure; and etching the dummy gate structure to extend the first opening and expose the first isolation structure.