Planar Amorphous Carbon Layer Formation via Dynamic Hydrogen Flow
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Solution Overview
Problem
Existing methods for forming amorphous carbon layers on patterned substrates often result in non-planar surfaces, leading to yield loss due to lack of etch selectivity and potential damage to underlying layers, especially when using metal, silicon oxide, or silicon nitride hardmasks.
Innovation Solution
The method involves introducing a hydrogen-containing precursor at a high ratio relative to a hydrocarbon into a substrate processing region and applying local plasma power to form a planar amorphous carbon layer, with an increasing atomic flow ratio of hydrogen to carbon, which preferentially etches high points, ensuring a more even deposition and improved planarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional PECVD is used to form amorphous carbon layers, then deposition can be achieved, but the surface becomes non-planar causing yield loss
Solution Approach 1:
The patent changes the hydrogen-to-carbon atomic flow ratio parameter during deposition. By increasing this ratio over time, the process transitions from initial deposition to planarization, allowing the same PECVD process to achieve both film formation and surface flattening without requiring additional processing steps
Solution Approach 2:
The patent employs dynamic adjustment of process parameters during deposition. The hydrogen-to-carbon ratio is not held constant but is increased over time, enabling the process to adapt from depositing material to preferentially etching high points, thereby achieving planar surfaces while maintaining productivity
2Reliability
If metal, silicon oxide, or silicon nitride hardmasks are used, then pattern transfer can be achieved, but etch selectivity is poor and underlying layers may be damaged
Solution Approach 1:
The patent introduces amorphous carbon as an intermediary hardmask layer between the pattern transfer process and the underlying sensitive layers. This carbon layer provides the necessary etch selectivity for reliable pattern transfer while protecting the underlying metal, silicon oxide, or silicon nitride layers from damage during the etching process
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 enhances manufacturing yield by creating a more planar top surface of the amorphous carbon layer, reducing the risk of damage to underlying layers and avoiding the need for complex hardware or chemical mechanical polishing, thereby increasing the efficiency and cost-effectiveness of integrated circuit production.
Implementation Method 1
applying plasma power to the substrate processing region. The methods further include forming a plasma from a combination of the hydrogen-containing precursor and the hydrocarbon precursor in the substrate processing region
Implementation Method 2
Plasma enhanced chemical vapor deposition (PECVD) has been used to form amorphous carbon layers as an alternative to traditional techniques
Implementation Method 3
increasing an atomic flow rate ratio from the first atomic flow rate ratio to a second atomic flow rate ratio (H:C) greater than two... Forming a second portion of a carbon layer having a second top interface. The second top interface may be more planar than the first top interface
Data Source
AI summary
Aspects of the disclosure pertain to methods of forming planar amorphous carbon layers on patterned substrates. Layers formed according to embodiments outlined herein have may improve manufacturing yield by making the top surface of an amorphous carbon layer more planar despite underlying topography or stoichiometric variations. The amorphous carbon layers may comprise carbon and hydrogen, may consist of carbon and hydrogen or may comprise or consist of carbon, hydrogen and nitrogen in embodiments. Methods described herein may comprise introducing a hydrogen-containing precursor at a relatively high ratio relative to a hydrocarbon into a substrate processing region and concurrently applying a local plasma power capacitively to the substrate processing region to form the planar layer. Alternatively an atomic flow ratio of hydrogen:carbon may begin low and increase discretely or smoothly during formation of the amorphous carbon layer.