Atomic Layer Etch With Rapid Thermal Activation for Carbon Films
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Solution Overview
Problem
Existing atomic layer etching methods are not effective for carbon-containing films and other low dielectric materials, as they are less reactive to ion bombardment and require higher temperatures, leading to long etching cycles with limited control.
Innovation Solution
A process involving exposure to reactive species generated by a plasma source, filtered to exclude ion bombardment, combined with rapid thermal cycles to incrementally increase the temperature above the activation temperature for etching, allowing for precise control of the etch process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ion bombardment atomic layer etching is used, then silicon-containing films can be etched effectively, but carbon-containing films and low dielectric materials cannot be etched successfully
Solution Approach 1:
The invention changes the activation mechanism from ion bombardment to thermal activation. By heating the substrate to temperatures between 50°C and 200°C, the reactive species gain sufficient energy to react with carbon-containing films and low dielectric materials, expanding material compatibility while maintaining etching effectiveness
Solution Approach 2:
The invention replaces the mechanical ion bombardment mechanism with a thermal field mechanism. Instead of using kinetic energy from ion impact to break bonds and enable etching, the invention uses thermal energy to activate the reactive species, allowing chemical reactions to proceed on materials that are insensitive to ion bombardment
2Reliability
If higher temperatures are used to enable etching of carbon-containing films, then etching can occur, but the etching cycles become very long with little control
Solution Approach 1:
The invention uses periodic pulsed heating instead of continuous high-temperature processing. Short heating pulses activate the etching reaction for a controlled duration, then the substrate is cooled to stop the reaction. This periodic action enables precise control over etch depth and significantly reduces total cycle time compared to continuous high-temperature etching
Solution Approach 2:
The invention implements feedback control by monitoring the etching process in real-time and adjusting heating pulse parameters accordingly. This allows dynamic optimization of etching rate and precision, ensuring consistent results while minimizing cycle time through adaptive process control
3Manufacturing precision
If ion bombardment is used for atomic layer etching, then the process can be controlled, but sub-surface damage occurs and uniformity is limited by plasma uniformity
Solution Approach 1:
The invention replaces mechanical ion bombardment with thermal activation, eliminating the harmful mechanical impact that causes sub-surface damage. The thermal field uniformly heats the entire substrate surface, enabling controlled chemical reactions without the localized damage associated with ion impact
Solution Approach 2:
The invention changes the reaction activation mechanism from kinetic energy-driven (ion bombardment) to thermal energy-driven. This parameter change enables uniform activation across the substrate surface through thermal conduction, achieving better etch uniformity that is independent of plasma distribution variations
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 enables precise and controlled etching of carbon-containing films and other low dielectric materials, improving etch uniformity and reducing sub-surface damage, while allowing for fine-tuned control over the etched amount.
Implementation Method 1
A plasma is generated from an etchant gas. The plasma contains a reactive species.
Implementation Method 2
the temperature of the layer is increased by exposing the layer to rapid thermal cycles. The rapid thermal cycles, for instance, can be produced by one or more pulsating lamps.
Data Source
AI summary
A process for etching a film layer on a semiconductor wafer is disclosed. The process is particularly well suited to etching carbon containing layers, such as hardmask layers, photoresist layers, and other low dielectric films. In accordance with the present disclosure, a reactive species generated from a plasma is contacted with a surface of the film layer. Simultaneously, the substrate or semiconductor wafer is subjected to rapid thermal heating cycles that increase the temperature past the activation temperature of the reaction in a controlled manner.