Two-Stage Oxide Film Formation for Low-Heat-Resistance Targets
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Solution Overview
Problem
Existing ALD film formation methods using high-concentration ozone gas or ozone and unsaturated hydrocarbon gas radicals for low-heat-resistance film targets face inefficiencies and potential deformation or denaturation issues, especially when forming thicker oxide films at low temperatures.
Innovation Solution
A two-stage oxide film formation method involving a first film formed using high-concentration ozone gas for ALD and a second film formed using radicals from the reaction between ozone and unsaturated hydrocarbon gas, allowing for efficient film growth on low-heat-resistance targets without significant deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If oxygen plasma is used as oxidizer to lower film formation temperature, then film formation temperature is reduced to about 100°C to 150°C, but the film formation target may undergo deformation and/or denaturation due to high reactivity for ashing
Solution Approach 1:
The invention changes the chemical composition parameter of the oxidizer from pure oxygen plasma to a mixed gas containing ozone and unsaturated hydrocarbon gas. This parameter change allows the generation of oxygen radicals at lower temperatures while reducing the harmful ashing effect on the film formation target, thus resolving the contradiction between temperature reduction and target protection.
Solution Approach 2:
The invention uses ozone, a strong oxidant, to generate oxygen radicals that enable low-temperature film formation. The unsaturated hydrocarbon gas enhances the radical generation efficiency, allowing effective oxidation at lower temperatures without requiring the high reactivity of pure oxygen plasma that causes target deformation.
2Temperature
If high-concentration ozone gas is used as oxidizer for ALD on low-heat-resistance targets, then film formation temperature can be set at or below 100°C with low reactivity for ashing, but film formation time increases and film formation efficiency decreases especially for thicker oxide films
Solution Approach 1:
The invention introduces unsaturated hydrocarbon gas to enhance the oxidation capability through radical reactions. This accelerates the oxide film formation rate while maintaining the low temperature condition and low ashing reactivity provided by ozone, thus resolving the contradiction between temperature control and formation efficiency.
3Temperature
If radicals yielded by radical reaction between ozone and unsaturated hydrocarbon gas are used as oxidizer, then film formation temperature is reduced and film formation speed is maintained fast, but the radicals are more reactive for ashing and may considerably deform or denature low-heat-resistance film formation target
Solution Approach 1:
The invention optimizes the concentration ratio of ozone to unsaturated hydrocarbon gas to control radical generation. By maintaining ozone as the dominant component with controlled amounts of unsaturated hydrocarbon gas, the system achieves sufficient radical activity for low-temperature formation while limiting excessive ashing reactivity that would deform the target.
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 achieves intended film characteristics and efficiency by suppressing deformation and denaturation of low-heat-resistance targets, even at low temperatures, through staged film formation using ozone and radical reactions.
Implementation Method 1
The first oxidizer supply process includes supplying ozone gas of 80 volume % or higher to the inside of the chamber and oxidizing the first adsorption layer
Implementation Method 2
employing both of high-concentration ozone gas and unsaturated hydrocarbon gas as oxidizers for ALD or CVD and performing film formation with utilization of oxidation power of radicals (i.e., OH radicals) yielded by a radical reaction between the high-concentration ozone gas and the unsaturated hydrocarbon gas
Data Source
AI summary
An oxide film formed on a film formation surface of a film formation target housed in a chamber includes a first film formed on the film formation surface and a second film formed on a first film surface. The first film is formed on the film formation surface of the film formation target by an ALD first film formation method that uses only an at least 80 volume % ozone gas as an oxidizing agent. The second film is formed on the first film surface by an ALD or CVD second film formation method that is different from the first film formation method. The second film formation method uses OH radicals generated by a radical reaction between high-concentration ozone gas and unsaturated hydrocarbon gas as an oxidizing agent and makes use of the oxidizing power of the radicals to form the oxide film.