Plasma Etching Cycles for Shape-Controlled Recess Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing plasma etching methods for silicon-containing films often result in shape abnormalities due to uncontrolled etching processes, leading to dimensional inaccuracies and inefficiencies in substrate processing.
Innovation Solution
A method involving a plasma processing apparatus that periodically alternates between high and low power supply cycles for source and bias power, using a first processing gas for etching and a second processing gas with silylation agents or acid components to adsorb onto the substrate, thereby controlling etching direction and suppressing shape abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous plasma etching is performed using a single processing gas, then etching speed is improved, but shape abnormalities occur due to uncontrolled etching direction
Solution Approach 1:
The patent applies periodic action by alternating between a first processing gas (for etching) and a second processing gas (for adsorption) in time-separated cycles. The first processing gas is supplied during etching periods to maintain high etching speed, while the second processing gas is supplied during adsorption periods to control etching direction by forming a protective layer on the film surface. This periodic switching resolves the contradiction by enabling both fast etching and shape control at different time intervals.
Solution Approach 2:
The patent employs preliminary action by supplying the second processing gas before the etching step to pre-adsorb protective species on the film surface. This preliminary adsorption creates a controlled interface that guides subsequent etching direction, preventing shape abnormalities before they occur. The protective layer is formed in advance during the adsorption period, ensuring proper etching morphology from the start of each etching cycle.
2Productivity
If high power is continuously supplied for etching, then etching efficiency is improved, but temperature control becomes difficult leading to process instability
Solution Approach 1:
The patent uses periodic action by switching between high power supply during etching periods and low or zero power supply during adsorption periods. This periodic power modulation allows the system to achieve high average etching efficiency while providing temperature relaxation intervals during adsorption phases. The alternating power cycles prevent continuous thermal accumulation, maintaining stable process temperature despite high instantaneous etching power requirements.
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 effectively reduces shape abnormalities by controlling etching direction and temperature, enhancing the precision and efficiency of the etching process, particularly in forming recesses with minimal dimensional differences.
Implementation Method 1
the etching target film is etched by a first plasma generated from a first processing gas supplied into the chamber
Implementation Method 2
a second processing gas supplied into the chamber is adsorbed onto the etching target film
Data Source
AI summary
An etching method includes: (a) providing a substrate having an etching target film and a mask on the etching target film to a substrate support in a plasma processing apparatus including a chamber, the substrate support, a plasma generator supplied with source power, and a bias electrode supplied with bias power; and (b) forming a recess by etching the etching target film. In (b), the source power and the bias power are periodically supplied in a cycle that includes a first period and a second period. In the first period, the etching target film is etched, and in the second period, the second processing gas is adsorbed onto the etching target film.