Multi-Source Plasma Processing for Substrate Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current plasma technologies for semiconductor surface processing face challenges such as non-uniformity of active species density, high costs, complexity, and lack of selectivity, particularly when processing larger substrates and sensitive materials like silicon nitride and silicon oxide layers, leading to damage and performance degradation in integrated circuits.
Innovation Solution
A plasma processing system with multiple independent subassemblies generating chemically distinct plasmas, each controlled by specific radiofrequency power and gas flow rates, allowing for selective processing of composite objects with different materials by alternating or overlapping plasma steps to achieve high selectivity and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single plasma source is used for processing large substrates, then the device complexity is reduced, but the uniformity of active species density across the substrate surface deteriorates
Solution Approach 1:
The plasma source is divided into multiple independent plasma sources (first plasma source and second plasma source) that can be controlled separately. Each plasma source processes a specific region of the substrate, allowing independent optimization of plasma parameters for different areas to achieve uniform processing across the entire large substrate surface.
Solution Approach 2:
Different plasma sources are configured with different gas compositions and flow rates to create locally optimized plasma conditions. The first plasma source uses a first gas composition while the second plasma source uses a second gas composition, allowing each region to have the specific plasma characteristics needed for optimal processing uniformity.
2Productivity
If high radiofrequency power is applied to achieve high processing speed, then the productivity increases, but the selectivity between different materials deteriorates
Solution Approach 1:
The processing is divided into multiple sequential steps, each using a different plasma source with optimized parameters for that specific step. This allows high processing speed in each step while maintaining material selectivity through tailored gas compositions and power levels specific to each material being processed.
Solution Approach 2:
The gas composition and radiofrequency power are changed between processing steps to optimize for different materials. The first plasma source uses a first gas composition and power level optimized for one material, while the second plasma source uses a second gas composition and power level optimized for another material, maintaining selectivity while achieving high overall processing speed.
3Ease of operation
If conventional plasma processing is used on composite materials, then the processing simplicity is maintained, but the selectivity and material damage control deteriorate
Solution Approach 1:
The processing system is segmented into multiple independently controllable plasma sources, each optimized for specific materials. While the system is more complex, the automated control and standardized interfaces maintain ease of operation, while the selective plasma parameters provide excellent material discrimination and damage control.
Solution Approach 2:
Each plasma source is configured with specific gas compositions and parameters optimized for processing particular materials in the composite structure. This local optimization provides high selectivity and controlled material interaction while the integrated system maintains operational simplicity through automated sequencing.
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 system achieves high selectivity and processing speed while ensuring uniformity across large substrates, reducing material loss and damage, and enhancing the performance of integrated circuits by independently controlling the etching of target and non-target materials.
Implementation Method 1
each plasma source of a subassembly being supplied independently by radiofrequency power Pi and by a flow-rate ni of gas i
Implementation Method 2
A plasma is a partially ionized gas containing electrically charged species (ions and electrons) as well as electrically neutral but very chemically active species, free radicals
Implementation Method 3
By means of these radicals and/or ions and of a controlled vacuum environment, the plasma offers unique possibilities for the depositing, etching and removal of materials
Data Source
AI summary
A system for treating an object with plasma includes a vacuum processing chamber having a holder on which the object to be treated is placed, at least two subassemblies each including at least one plasma source able to generate a plasma and being supplied with radio-frequency power Pi and with a gas i of independent flow rate ni. The plasma generated by one of the subassemblies is a partially ionized gas or gas mixture of different chemical nature from the plasma generated by the other subassembly or subassemblies. A process for selectively treating a composite object employing such a device is described.