Self-Planarizing Carbon Gapfill Across Varying Feature Geometries
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Solution Overview
Problem
Conventional chemical vapor deposition techniques struggle to fill gaps between semiconductor structures with varying widths and aspect ratios without creating voids or seams, especially as device geometries shrink and thermal budgets are reduced.
Innovation Solution
A method using dual-frequency radiofrequency (RF) plasma enhanced chemical vapor deposition (PECVD) with a high frequency RF power of 10-40 MHz to concurrently deposit and etch a carbon gapfill layer, ensuring uniform coverage across features with varying critical dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CVD techniques are used to fill gaps between semiconductor structures, then deposition occurs, but material overgrowth at the top creates voids and seams before complete filling
Solution Approach 1:
The patent changes the RF frequency parameter from conventional low frequency (e.g., 13.56 MHz) to high frequency (10-40 MHz range). This parameter change fundamentally alters the plasma chemistry and deposition kinetics, enabling simultaneous deposition and etching that prevents top surface overgrowth and eliminates voids/seams in the gapfill layer
Solution Approach 2:
The patent implements continuous concurrent deposition and etching throughout the gapfill process. The high frequency plasma maintains ongoing material deposition while simultaneously etching deposited species, creating a continuous self-regulating process that prevents void formation and ensures complete gap filling without interruption or sequential steps
2Adaptability or versatility
If a single device has multiple gaps with varying widths and aspect ratios, then filling all gaps is required, but conventional processes cannot fill gaps with different CDs and aspect ratios uniformly
Solution Approach 1:
The high frequency plasma process provides universal gapfilling capability that works across multiple gap geometries simultaneously. The concurrent deposition-etching mechanism adapts to different critical dimensions and aspect ratios without requiring process parameter changes, making the single process universally applicable to varying gap structures on the same device
Solution Approach 2:
The patent utilizes high RF frequency (10-40 MHz) as a key parameter change that enables the plasma to automatically adapt to different gap geometries. This frequency parameter creates plasma conditions where deposition and etching rates self-regulate according to local geometry, allowing uniform gapfill across varying widths and aspect ratios
3Manufacturing precision
If device geometries shrink and thermal budgets are reduced, then gap filling becomes more difficult, but conventional CVD cannot achieve void-free filling in high aspect ratio structures
Solution Approach 1:
The patent replaces thermal-driven conventional CVD with a plasma-driven chemical process operating at lower temperatures. The high frequency plasma provides the necessary reaction activation through ion bombardment and reactive species rather than thermal energy, enabling gapfilling in high aspect ratio structures within reduced thermal budgets while achieving void-free filling
Solution Approach 2:
The patent changes from thermal-based deposition to plasma-based deposition by using high frequency RF power. This parameter change enables the process to operate at lower substrate temperatures while maintaining effective gapfilling capability in high aspect ratio structures, achieving void-free filling within reduced thermal budgets
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 a self-planarizing carbon gapfill layer that is substantially uniform across features with varying critical dimensions, reducing pattern loading effects and eliminating the need for subsequent polishing processes.
Implementation Method 1
A hydrocarbon precursor gas is flowed into the processing volume at a precursor flow rate for providing a deposition species. A high frequency radio frequency (RF) power is provided to the processing volume to generate and maintain a RF plasma in the processing volume, wherein the high frequency RF power comprises a frequency of about 10 MHz to about 40 MHz. A carbon gapfill layer is formed over the at least two features by using the RF plasma to concurrently deposit the deposition species on the substrate
Implementation Method 2
An etchant gas is flowed into the processing volume at an etchant flow rate for providing an etch species. A carbon gapfill layer is formed over the at least two features by using the RF plasma to concurrently deposit the deposition species on the substrate and etch the deposited deposition species using the etch species
Data Source
AI summary
The present disclosure provides methods for forming a carbon gapfill layer. The methods include positioning a substrate having a top surface with at least two features disposed thereon on a substrate support in a processing volume. A hydrocarbon precursor gas is flowed into the processing volume. An etchant gas is flowed into the processing volume. A high frequency radio frequency (RF) power is provided to generate and maintain a RF plasma in the processing volume, where the high frequency RF power includes a frequency of about 10 MHz to about 40 MHz. A carbon gapfill layer is formed over the at least two features by using the RF plasma to concurrently deposit the deposition species on the substrate and etch the deposited deposition species using the etch species.