Amorphous TiN PEALD Deposition With Variable-Frequency RF Plasma
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Solution Overview
Problem
The existing methods for forming titanium nitride (TiN) spacer films on patterned substrates result in crystalline TiN films with high impurity levels, leading to difficulties in removing impurities and potential damage to underlying layers due to high temperature plasma exposure.
Innovation Solution
A method involving the formation of an amorphous TiN film with low impurities by using a variable frequency RF power in a reaction chamber, where a titanium-containing gas and a nitrogen-containing gas are activated to form a TiN film with impurity levels of 25% or less, primarily composed of oxygen and carbon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the TiN film is formed at high temperature over 300°C and exposed to plasma for a long time to remove impurities, then the impurity removal is improved, but the sublayer such as hard mask is damaged and the reactor temperature increases leading to film quality deterioration
Solution Approach 1:
The patent changes the process parameters by forming TiN film at low temperature (100-250°C) instead of high temperature (over 300°C), and uses variable frequency RF power (13-30 MHz) to optimize plasma conditions. This parameter change allows impurity removal without damaging the sublayer or causing reactor overheating
Solution Approach 2:
The patent employs periodic action by using variable frequency RF power with frequency switching between 13-30 MHz. The RF power is applied in a controlled manner with specific timing (RF-ON for 1.0-3.0 seconds) during the film formation process, creating optimal plasma conditions for impurity removal while preventing excessive heating
2Productivity
If conventional plasma treatment is used to remove impurities from TiN film, then the process time is reduced, but the impurity removal efficiency is insufficient and the film requires long exposure time
Solution Approach 1:
The patent changes the plasma generation parameters by using variable frequency RF power (13-30 MHz) instead of conventional fixed frequency. This creates more effective plasma that removes impurities faster, achieving both reduced process time and high impurity removal efficiency within 1-3 seconds of RF-ON time
Solution Approach 2:
The patent replaces the conventional mechanical/thermal plasma treatment approach with a controlled variable frequency RF plasma field. This substitution allows precise control of energy delivery to the film, achieving rapid and efficient impurity removal without the need for prolonged exposure
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
The method effectively produces an amorphous TiN film with reduced impurity levels, improving the selectivity and quality of the spacer film, while avoiding the damage and quality issues associated with high temperature plasma exposure.
Implementation Method 1
supplying a second gas to the reaction chamber, and activating the second gas by applying a power to the reaction chamber, wherein a frequency of the power may be a variable frequency
Implementation Method 2
A method involving the formation of an amorphous TiN film with low impurities by using a variable frequency RF power in a reaction chamber, where a titanium-containing gas and a nitrogen-containing gas are activated to form a TiN film
Data Source
AI summary
Provided is a substrate processing method using a PEALD method in which an amorphous TiN film is formed on the substrate. The substrate processing method comprises providing the substrate to a reaction chamber, supplying a first gas to the reaction chamber, supplying a second gas to the reaction chamber, and applying a power to the reaction chamber, wherein a frequency of the power is a variable frequency, wherein the second gas is activated by the power.