Diamond-Like Carbon Hardmask Film Stress Reduction
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Solution Overview
Problem
Carbon-containing hardmasks formed by plasma-enhanced chemical vapor deposition often exhibit internal stress, leading to deformation and line warpage issues during etch operations, which degrade device performance.
Innovation Solution
A method involving the deposition of a diamond-like carbon (DLC) layer followed by a plasma treatment using a non-reactive gas and radio frequency (RF) bias power to reduce film stress, with the RF power ranging from 100 W to 10,000 W, is employed to mitigate internal stress in the hardmask layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon-containing hardmasks are formed by PECVD, then etch selectivity and mechanical properties are improved, but internal stress causes deformation and line warpage
Solution Approach 1:
A release layer is deposited between the substrate and the hardmask layer during the PECVD process. This release layer is specifically designed to counteract the internal stress that develops in the carbon-containing hardmask, preventing deformation and line warpage before they occur during etch operations
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers: a substrate, a release layer with specific stress characteristics, and a carbon-containing hardmask layer. This composite approach allows the release layer to compensate for the internal stress in the hardmask, maintaining shape integrity while preserving etch selectivity
2Ease of manufacture
If hardmask material includes internal stress, then film formation is achieved, but the hardmask material deforms during etch operations
Solution Approach 1:
The release layer acts as a counterweight to the internal stress in the hardmask layer. By carefully controlling the stress characteristics of the release layer, it provides an opposing force that balances the internal stress, preventing film deformation while allowing the hardmask to maintain its structural integrity during manufacturing
3Stress or pressure
If plasma treatment with RF bias power is applied, then film stress is reduced, but process complexity increases
Solution Approach 1:
The patent applies plasma treatment with controlled RF bias power to modify the physical and chemical parameters of the hardmask layer. By adjusting parameters such as RF power, gas composition, and treatment duration, the internal stress is reduced while maintaining the hardmask's functional properties, achieving stress reduction through parameter optimization rather than process complexity
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 plasma treatment effectively reduces film stress in the DLC layer, preventing deformation and maintaining refractive index and uniformity, thereby improving the shape integrity and performance of the hardmasks.
Implementation Method 1
generating a plasma from the non-reactive gas in the processing volume to treat the DLC layer
Implementation Method 2
applying a radio frequency (RF) bias power of about 100 W to about 10,000 W
Data Source
AI summary
Embodiments of the present disclosure generally relate to methods of forming hardmasks. Embodiments described herein enable, e.g., formation of carbon-containing hardmasks having reduced film stress. In an embodiment, a method of processing a substrate is provided. The method includes positioning a substrate in a processing volume of a processing chamber and depositing a diamond-like carbon (DLC) layer on the substrate. After depositing the DLC layer, the film stress is reduced by performing a plasma treatment, wherein the plasma treatment comprises applying a radio frequency (RF) bias power of about 100 W to about 10,000 W.