Gas Spacer Formation for Selective Gate Spacer Etching
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Solution Overview
Problem
As semiconductor devices continue to shrink in feature size, the integration of electronic components becomes more challenging, leading to issues such as device defects and reduced performance due to the complexity of forming gas spacers in the manufacturing process.
Innovation Solution
The process involves using an etching method at a temperature less than 0°C with an etchant like hydrogen fluoride and a catalyst such as water or ethanol to selectively remove dummy gate spacers, improving etch selectivity and reducing device defects, and replacing traditional spacers with gas spacers that have a low dielectric constant to decrease parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional etching processes are used to remove dummy gate spacers, then the manufacturing process can proceed, but etch selectivity is insufficient leading to device defects
Solution Approach 1:
The patent applies parameter changes by conducting the etching process at sub-zero temperatures (below 0°C) and adjusting etchant composition (using hydrogen fluoride with water or ethanol catalysts). These parameter modifications enhance etch selectivity for dummy gate spacer removal while preventing damage to surrounding structures, directly resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The patent introduces intermediary substances (water or ethanol catalysts) into the etching process. These catalysts facilitate selective etching of dummy gate spacers by enhancing the chemical reaction specificity, thereby improving both etch selectivity and device reliability without requiring more complex manufacturing steps.
2Speed
If traditional solid spacers are used, then the manufacturing process is simpler, but parasitic capacitance increases reducing circuit speed
Solution Approach 1:
The patent replaces traditional solid dielectric spacers with gas-filled spacers (vacuum or inert gas). This pneumatic approach significantly reduces parasitic capacitance between adjacent conductive structures, thereby increasing circuit speed. The gas spacer structure, while slightly more complex to manufacture, provides substantial performance benefits that justify the increased device complexity.
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 enhances the selectivity of the etching process, reduces device defects, and improves the performance of semiconductor devices by lowering parasitic capacitance and increasing circuit speed and reliability.
Implementation Method 1
removing the second gate spacer using an etching process to form a first opening, the etching process being performed at a temperature less than 0° C.
Implementation Method 2
an etchant like hydrogen fluoride and a catalyst such as water or ethanol to selectively remove dummy gate spacers
Data Source
AI summary
A method of forming a gas spacer in a semiconductor device and a semiconductor device including the same are disclosed. In accordance with an embodiment, a method includes forming a gate stack over a substrate; forming a first gate spacer on sidewalls of the gate stack; forming a second gate spacer on sidewalls of the first gate spacer; removing the second gate spacer using an etching process to form a first opening, the etching process being performed at a temperature less than 0° C., the etching process using an etching solution including hydrogen fluoride; and depositing a dielectric layer over the first gate spacer and the gate stack, the dielectric layer sealing a gas spacer in the first opening.