Plasma Atomic Layer Etching with Rapid Thermal Activation
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Solution Overview
Problem
Traditional atomic layer etching methods are ineffective for carbon-containing films and low dielectric materials due to low reactivity to ion bombardment, leading to inefficient and uncontrollable etching processes.
Innovation Solution
A process involving exposure to reactive species generated by a plasma source, filtered to exclude charged particles, combined with rapid thermal cycles to incrementally increase the temperature of the film layer above the activation temperature for precise etching, allowing controlled etching of carbon-containing films without ion bombardment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If ion bombardment is used for atomic layer etching, then silicon-containing films can be etched effectively, but carbon-containing films and low dielectric materials cannot be etched due to low reactivity
Solution Approach 1:
The patent changes the activation method from ion bombardment to thermal activation by rapid thermal processing (RTP). This parameter change enables the etching process to work on carbon-containing films and low dielectric materials that are not reactive to ion bombardment, thereby improving material compatibility while maintaining etch effectiveness through temperature-controlled chemical reactions
Solution Approach 2:
The patent replaces the mechanical ion bombardment system with a thermal field system (RTP). Instead of using kinetic energy from ion impact to activate the etching reaction, the system uses thermal energy to activate chemical reactions between reactive species and the film, enabling effective etching of materials like carbon-containing films that are insensitive to ion bombardment
2Adaptability or versatility
If higher temperatures are used to enable etching of carbon-containing films, then etching can occur, but etching cycles become very long and process control is lost
Solution Approach 1:
The patent employs periodic rapid thermal processing cycles to incrementally increase the temperature above the activation threshold only during specific time intervals. This periodic heating enables controlled chemical reactions for etching carbon-containing films while limiting the total time at high temperature, thus maintaining productivity and process control
Solution Approach 2:
The patent applies preliminary thermal activation using RTP to prepare the film surface and activate chemical reactions before introducing reactive species. This preliminary action enables the etching process to proceed at lower temperatures with better control, reducing cycle time and improving productivity compared to sustained high-temperature processing
3Productivity
If plasma is used to generate reactive species, then etching can be performed, but ion bombardment causes sub-surface damage and reduces precision
Solution Approach 1:
The patent extracts only the beneficial reactive neutral species from the plasma while excluding the harmful ions. By using a filter structure that allows reactive neutrals to pass through while blocking ions, the system maintains etching capability through chemical reactions while eliminating ion bombardment damage, thereby improving surface quality and manufacturing precision
Solution Approach 2:
The patent introduces a filter structure as an intermediary between the plasma source and the substrate. This intermediary selectively transmits reactive neutral species while blocking ions, enabling the system to achieve etching through chemical reactions without the damaging effects of ion bombardment, thus preserving surface integrity and precision
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
Enables precise and controlled etching of carbon-containing films with improved uniformity and etch rate control, suitable for semiconductor manufacturing, enhancing the performance of underlying devices.
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.