Bottom-Up Carbon Gapfill Using Coetaneous Deposition-Etch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional chemical vapor deposition techniques struggle with voids and seams in high aspect ratio structures due to overgrowth and lack of precise control over carbon deposition, especially when filling gaps with varying critical dimensions and aspect ratios.
Innovation Solution
A coetaneous deposition and etch process using RF plasma with controlled flux ratios of hydrocarbon precursor and etchant gases to form a carbon gapfill layer, allowing for a bottom-up growth approach.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CVD techniques are used to fill high aspect ratio gaps, then material deposition occurs, but overgrowth at the top creates voids and seams before the gap is completely filled
Solution Approach 1:
The patent inverts the conventional deposition approach by using a low deposition rate that allows etching to remove material faster than it deposits, creating a net removal effect that prevents top-hat overgrowth and enables complete gap filling without voids or seams
Solution Approach 2:
The patent changes the deposition rate parameter to be sufficiently low (controlled by precursor flow rate and RF power) so that the deposition process does not outpace the etching process, thereby preventing overgrowth at the gap opening while maintaining gap filling
2Productivity
If deposition rate is increased to fill gaps faster, then productivity improves, but voids and seams form due to premature cutoff of depositing material
Solution Approach 1:
The patent maintains continuous coetaneous deposition and etching throughout the process, ensuring that material is continuously removed from the gap opening at the same rate it deposits, preventing premature cutoff and ensuring uniform filling throughout the gap duration
Solution Approach 2:
The etching process acts as a feedback mechanism that continuously removes excess material from the gap opening, sensing and correcting overgrowth tendencies in real-time to maintain uniform deposition throughout the gap region
3Device complexity
If single deposition process is used to fill multiple gaps with varying CDs and aspect ratios, then process simplicity is maintained, but uniform deposition across different geometries becomes difficult
Solution Approach 1:
The patent creates a universal deposition-etching process that simultaneously handles multiple gap geometries (different CDs and aspect ratios) with a single process, where the coetaneous deposition and etching mechanism adapts to fill various gap sizes uniformly without requiring separate process 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 ensures void-free and seam-free filling of trenches with varying CDs and aspect ratios, providing uniform deposition rates and planarity, reducing the need for subsequent polishing processes.
Implementation Method 1
generating an RF plasma in the processing volume to form a deposition species from the hydrocarbon precursor gas and an etch species from the etchant gas
Implementation Method 2
coetaneous deposition and etch processes... generating a RF plasma in the processing volume from the hydrocarbon precursor gas and the etchant gas to form the carbon gapfill layer
Data Source
AI summary
A method for forming a carbon gapfill layer on a substrate is provided. The method includes positioning a substrate with at least one feature disposed thereon in a processing volume of a process chamber, flowing a hydrocarbon precursor gas into the processing volume at a precursor flow rate, flowing an etchant gas into the processing volume at an etchant flow rate, and generating a RF plasma in the processing volume from the hydrocarbon precursor gas and the etchant gas to form the carbon gapfill layer in the at least one feature.