Selective Carbon Deposition for Etching Protection
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Solution Overview
Problem
In substrate processing, amorphous hard mask (AHM) films used for etching protection face challenges such as substrate bowing due to increased weight from thicker films and difficulty in reducing feature pitch with photoresist films, necessitating improved carbon deposition techniques for extended etching protection without initial thickness increase.
Innovation Solution
The method involves selective carbon deposition using atomic layer deposition (ALD) onto existing carbon films, redepositing carbon only on the AHM film during etching, and using a carbon seed layer to extend etching protection without increasing the initial film thickness, employing precursor gases like carbon tetrabromide and tribromomethane, and controlling the RF plasma generating system to manage the deposition process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If thicker carbon films are deposited to extend etching protection, then etching protection duration is improved, but substrate bowing occurs due to increased weight
Solution Approach 1:
The carbon film is deposited in multiple thin layers rather than one thick layer. The process involves alternating deposition and etching steps where carbon is deposited in thin increments (e.g., 1-10 nm per step) and then etched selectively, repeating this cycle to achieve the required total thickness. This segmentation prevents substrate bowing by avoiding the weight accumulation of a single thick deposit while still providing extended etching protection through the cumulative effect of multiple thin layers.
Solution Approach 2:
The deposition process uses periodic alternating steps of carbon deposition and selective etching. Carbon is deposited in thin layers, then selectively etched in specific regions, and this cycle repeats multiple times. This periodic action allows the carbon film to be rebuilt in manageable increments, extending protection duration without the harmful weight effect of a single thick deposit that would cause substrate bowing.
2Manufacturing precision
If photoresist films are used to reduce feature pitch, then manufacturing precision is improved, but the process complexity increases
Solution Approach 1:
A carbon film serves as an intermediary layer between the pattern definition step and the final etching step. The carbon film is deposited conformally over the patterned substrate, then selectively removed or modified in subsequent steps to transfer the pattern with improved precision. This intermediary carbon layer enables precise feature pitch reduction by providing an additional degree of freedom in pattern transfer, avoiding the need for more complex photoresist-based approaches.
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 extends etching protection for deeper etching periods without substrate bowing and allows for precise pitch reduction, maintaining the initial film thickness while ensuring adequate protection for features during etching.
Implementation Method 1
a radio frequency (RF) plasma generating system configured to generate plasma in the processing chamber
Implementation Method 2
supplying at least one carbon-containing precursor gas into the processing chamber in a dosing step
Data Source
AI summary
A method for depositing carbon on a substrate in a processing chamber includes arranging the substrate on a substrate support in the processing chamber. The substrate includes a carbon film having a first thickness formed on at least one underlying layer of the substrate. The method further includes performing a first etching step to etch the substrate to form features on the substrate, remove portions of the carbon film, and decrease the first thickness of the carbon film, selectively depositing carbon onto remaining portions of the carbon film, and performing at least one second etching step to etch the substrate to complete the forming of the features on the substrate.