DRAM Capacitor Silicon Nitride Etching With HF Temperature Control
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Solution Overview
Problem
Existing etching methods for silicon-containing films in DRAM capacitors face challenges in achieving precise control over etching selectivity and preventing bowing of openings, particularly when using hydrogen fluoride gas.
Innovation Solution
An etching method involving a substrate temperature set to 10°C or higher, using a first processing gas comprising hydrogen fluoride gas and a carbon-containing gas, followed by a second processing gas to etch different silicon-containing films, with controlled temperature adjustments for each etching step.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen fluoride gas is used for etching silicon-containing films, then etching capability is improved, but control over etching selectivity and prevention of opening bowing deteriorates
Solution Approach 1:
The patent applies parameter changes by adjusting substrate temperature to 10°C or higher during hydrogen fluoride-based etching. This temperature parameter modification enables better control over etching selectivity between different silicon-containing films while preventing opening bowing, thus resolving the contradiction between maintaining high etching capability and improving manufacturing precision.
Solution Approach 2:
The patent implements local quality by creating different etching conditions for different regions of the substrate. By controlling temperature distribution and gas flow, the etching process achieves high selectivity for specific silicon-containing films while maintaining overall etching efficiency, thereby improving precision without sacrificing productivity.
2Productivity
If hydrogen fluoride gas is used for etching silicon-containing films, then etching capability is improved, but prevention of opening bowing deteriorates
Solution Approach 1:
The patent changes the temperature parameter to 10°C or higher during etching with hydrogen fluoride gas. This parameter adjustment prevents opening bowing by controlling the etching rate uniformity across the film thickness, while still maintaining the high etching capability provided by hydrogen fluoride gas.
3Manufacturing precision
If substrate temperature is increased to 10°C or higher, then etching selectivity is improved, but process complexity increases
Solution Approach 1:
The patent implements a straightforward temperature parameter change to 10°C or higher, which can be achieved through simple substrate heating mechanisms. This single parameter adjustment provides significant improvement in etching selectivity without requiring complex multi-parameter control systems, thus minimizing the increase in 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
Improves etching selectivity and reduces bowing of openings in silicon nitride films, enhancing the precision and effectiveness of DRAM capacitor manufacturing.
Implementation Method 1
etching the single-layer film using a plasma formed from a first processing gas
Implementation Method 2
etching the single-layer film using a plasma formed from a first processing gas including a hydrogen fluoride gas
Implementation Method 3
setting a temperature of the substrate support or the substrate to 10° C. or higher
Data Source
AI summary
An etching method includes (a) providing a substrate on a substrate support in a chamber, the substrate including a film stack including two or more different silicon-containing films, a single-layer film on the two or more different silicon-containing films, the single-layer film including silicon and nitrogen, and a mask on the single-layer film, the mask having a side wall defining an opening; (b) setting a temperature of the substrate support or the substrate to 10° C. or higher; and (c) etching the single-layer film using a plasma formed from a first processing gas, the first processing gas including a hydrogen fluoride gas.