Metal Film Deposition With Sacrificial Cap Layer Protection
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Solution Overview
Problem
When forming a second metal film on a surface of a first metal film, such as a tungsten film on a titanium nitride film, the surface etching by film-forming gases can deteriorate the film properties, particularly affecting the barrier performance and oxidation resistance of the first metal film.
Innovation Solution
A substrate processing method involving the formation of a cap film containing a Group 13 or Group 14 element on the first metal film, followed by the deposition of a second metal film while removing part of the cap film using a gas containing the second metal element and a reactive gas, to improve film properties and suppress oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a second metal film is formed on a first metal film using film-forming gas, then the second metal film can be deposited, but the surface of the first metal film is etched and film properties deteriorate
Solution Approach 1:
A cap film containing Group 13 or Group 14 elements is introduced as an intermediary layer between the first metal film and the second metal film. This cap film serves as a protective mediator that prevents direct contact and harmful interaction between the film-forming gas and the first metal film surface, while still allowing controlled removal of the cap film to enable second metal film formation.
Solution Approach 2:
The cap film is formed in advance on the first metal film before the second metal film deposition process. This preliminary action creates a protective barrier that prevents surface etching of the first metal film during subsequent processing, and the cap film can be selectively removed only when needed for second metal film formation.
2Reliability
If the surface of the first metal film is etched by film-forming gas, then the second metal film can be formed, but the barrier performance and oxidation resistance of the first metal film deteriorate
Solution Approach 1:
The cap film acts as a protective intermediary that shields the first metal film from oxidation during the second metal film formation process. By preventing direct exposure to oxidizing environments, the cap film maintains the barrier performance and oxidation resistance of the first metal film throughout processing.
Solution Approach 2:
The cap film is formed preliminarily on the first metal film to establish protective coverage before any oxidation-prone processes occur. This advance protection ensures that the first metal film's barrier properties and oxidation resistance are maintained throughout subsequent processing steps.
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 enhances the barrier properties and reduces resistivity of the second metal film while preventing the etching and oxidation of the first metal film, thereby improving overall film quality.
Implementation Method 1
forming a third film containing a second metal element on the substrate while removing at least part of the second film by performing: (a) supplying a gas containing the second metal element to the substrate; and (b) supplying a first reactive gas to the substrate
Data Source
AI summary
According to the present disclosure, there is provided a technique capable of improving film properties. According to one aspect of the technique of the present disclosure, there is provided a substrate processing method including: preparing a substrate comprising a first film containing a first metal element and a second film containing a Group 13 element or a Group 14 element and formed on the first film; and forming a third film containing a second metal element on the substrate while removing at least part of the second film by performing: supplying a gas containing the second metal element to the substrate; and supplying a first reactive gas to the substrate.