Cut Metal Gate Air Spacer Formation Without Etchant Penetration
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Solution Overview
Problem
As semiconductor devices continue to shrink in feature size, challenges arise in integrating more components into a given area, including issues with forming air spacers and maintaining process window efficiency during the cut metal gate process, which affects the manufacturing yield and efficiency.
Innovation Solution
A method involving the formation of air spacers by removing residual oxygen between the fill material and the interlayer dielectric layer, preventing etchant penetration and allowing for a wider process window, includes steps like patterning hard masks, depositing and etching masking layers, and using cyclical etching processes to cut metal gates and remove oxide materials, ultimately capping voids to form air spacers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used to remove oxide materials during the cut metal gate process, then oxide removal is achieved, but etchant penetration causes damage and limits process window
Solution Approach 1:
The patent applies preliminary action by removing residual oxygen from the interface between the fill material and interlayer dielectric layer before performing the etching process. This pre-treatment step creates a controlled environment that prevents etchant penetration damage during subsequent oxide removal, thereby widening the process window and improving manufacturing precision
Solution Approach 2:
The patent implements preliminary anti-action by eliminating residual oxygen that would otherwise facilitate harmful etchant penetration. By removing this harmful element beforehand, the process prevents potential damage during the etching operation, allowing for more precise oxide removal with a wider process margin
2Quantity of substance
If feature sizes are reduced to increase integration density, then more components can be integrated into a given area, but process window efficiency and manufacturing yield deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the chemical environment at the fill material-dielectric interface through residual oxygen removal. This parameter modification enables precise etching at reduced feature sizes without compromising manufacturing yield, thereby supporting higher integration density while maintaining productivity
3Ease of manufacture
If residual oxygen is present between fill material and interlayer dielectric layer, then conventional processes can proceed, but etchant penetration and process window limitations occur
Solution Approach 1:
The patent performs preliminary action by removing residual oxygen before the etching process. This additional preparatory step, while slightly increasing process complexity, dramatically improves reliability by preventing etchant penetration and widening the process window, ensuring robust manufacturing
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 manufacturing efficiency and yield by preventing unwanted etchant penetration and damage, widening the process window for spacer removal and improving the integration of air spacers in semiconductor devices.
Implementation Method 1
removing the oxide is performed at least in part with a mixture of hydrogen fluoride and ammonia
Implementation Method 2
filling a region between the first metal gate and the second metal gate with a dielectric material
Implementation Method 3
using cyclical etching processes to cut metal gates and remove oxide materials
Data Source
AI summary
A conductive gate over a semiconductor fin is cut into a first conductive gate and a second conductive gate. An oxide is removed from sidewalls of the first conductive gate and a dielectric material is applied to the sidewalls. Spacers adjacent to the conductive gate are removed to form voids, and the voids are capped with a dielectric material to form air spacers.