Plasma Processing Method for Mask Pattern Protection
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Solution Overview
Problem
In semiconductor device manufacturing, the miniaturization of line-and-space intervals leads to protective films blocking mask patterns during plasma etching, preventing effective plasma access and hindering etching processes.
Innovation Solution
A plasma processing method using a mixed gas of silicon, oxygen, nitrogen, and hydrogen elements to form a protective film that prevents deposition in the direction parallel to the substrate surface, allowing for improved pattern processing in narrow spaces by controlling the power modulation and gas composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective film is deposited using plasma in conventional methods, then the mask is protected during etching, but the protective film blocks the opening of the mask pattern when the space interval between mask patterns is narrowed
Solution Approach 1:
The patent changes the chemical composition parameters of the plasma gas from conventional single-component gases (SF6, CF4) to a mixed gas containing silicon-based gas (SiF4, SiCl4), oxygen-based gas, nitrogen-based gas, and hydrogen-based gas. This parameter change modifies the deposition characteristics of the protective film to reduce lateral growth and prevent blocking of narrow mask pattern openings while maintaining mask protection functionality.
Solution Approach 2:
The patent uses a composite gas mixture comprising multiple components (silicon-based gas, oxygen-based gas, nitrogen-based gas, and hydrogen-based gas) to generate plasma. This composite approach creates a protective film with modified properties that combines the benefits of protection with reduced lateral deposition, solving the contradiction between mask protection and pattern accessibility.
2Area of moving object
If the space interval between mask patterns is reduced for miniaturization, then device density increases, but the protective film deposited in the lateral direction blocks the mask pattern opening
Solution Approach 1:
By changing the gas composition parameters to a mixed gas system, the patent controls the deposition anisotropy to minimize lateral film growth. This allows narrower space intervals to be maintained without blocking, enabling continued device miniaturization while preserving plasma access to mask openings.
3Manufacturing precision
If a protective film is formed on the mask, then etching selectivity is improved, but the plasma cannot enter the space due to protective film deposition in the opening
Solution Approach 1:
The composite gas mixture creates a protective film that maintains etching selectivity benefits while avoiding the blocking problem. The synergistic combination of silicon-based, oxygen-based, nitrogen-based, and hydrogen-based gases produces a film with controlled deposition characteristics that preserves plasma penetration capability.
Solution Approach 2:
The modified gas composition parameters alter the film deposition kinetics to reduce lateral growth rate, ensuring that the protective film forms adequately on mask surfaces for selectivity while not accumulating in the openings to block plasma access and maintain etching efficiency.
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 method effectively prevents protective film deposition in mask pattern openings, enabling efficient etching even in narrow spaces and improving pattern processing selectivity.
Implementation Method 1
supplying a silicon-based gas containing at least SiF4 gas or SiCl4 gas and a processing gas containing oxygen gas or nitrogen gas into the processing chamber to generate plasma
Implementation Method 2
forming a silicon oxide film or a silicon nitride film as a protective film on the silicon carbide substrate
Data Source
AI summary
An object of the invention is to provide a plasma processing method capable of preventing a protective film from being deposited in a direction parallel to a substrate surface to block an opening of a mask pattern and improving pattern processing even in a narrow space.The plasma processing method according to the invention is a plasma processing method for plasma-etching an etching target film using a protective film formed on a mask, and includes a step of forming the protective film on the mask using plasma generated by a mixed gas of a silicon element-containing gas, an oxygen element-containing gas, a nitrogen element-containing gas, and a hydrogen element-containing gas.The hydrogen element-containing gas is H2 gas, HBr gas, or CH4 gas. The oxygen element-containing gas is O2 gas, CO gas, CO2 gas, COS gas, or SO2 gas.