Plasma Processing Resist Modification Electron Injection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional capacitively coupled plasma etching methods face challenges in improving the etching resistance of ArF resist patterns, leading to issues like resist pattern collapse, surface roughness, and poor line edge roughness due to low plasma resistance, which affects the accuracy and stability of thin film processing in semiconductor and flat panel display manufacturing.
Innovation Solution
A plasma processing method that injects high-energy electrons into the resist pattern using a negative DC voltage in the same processing chamber, enhancing the etching resistance of the resist pattern by modifying it before the etching process, allowing for improved selectivity and accuracy without requiring additional equipment or altering the existing etching apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional resist modification methods (electron beam irradiation, UV irradiation, H2 or HBr plasma irradiation, ion beam irradiation) are used to improve etching resistance of ArF resist, then etching resistance is enhanced, but apparatus cost increases and throughput decreases due to requiring exclusive processing vessels
Solution Approach 1:
The patent combines the resist modification function and etching function into a single capacitively coupled plasma processing apparatus. The modification electrode and substrate electrode work together in the same chamber, allowing resist modification and subsequent etching to be performed sequentially without transferring wafers between different apparatus, thereby maintaining high etching resistance while preserving production throughput.
Solution Approach 2:
The capacitively coupled plasma processing apparatus is designed to perform multiple functions: it can modify the resist pattern using plasma generated at the modification electrode, and then perform the etching process using plasma generated at the substrate electrode. This multi-functionality eliminates the need for separate dedicated modification apparatus, reducing cost while maintaining etching resistance.
2Stability of the object's composition
If electron beam irradiation or UV irradiation is used before exposure to light, then resist film quality is improved, but light transmissivity of the resist pattern changes, deteriorating exposure performance
Solution Approach 1:
The resist modification is performed after the resist pattern is formed by lithography but before the etching process. This timing ensures that the resist pattern structure is already established, and the plasma modification enhances etching resistance without affecting light transmissivity during exposure, as the modification occurs in the plasma phase rather than during photolithography.
3Reliability
If ion beam irradiation is used after exposure to light, then resist pattern can be modified, but the resist pattern is easily damaged by ion impact
Solution Approach 1:
The patent uses plasma modification instead of direct ion beam irradiation. Plasma contains reactive species and electrons that can modify the resist chemistry without the high-energy ion impact that causes physical damage. The plasma parameters (power, pressure, gas composition) are controlled to achieve effective modification while minimizing harmful effects on the resist pattern structure.
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 method effectively increases the etching resistance of the resist pattern, reducing deformation and improving the accuracy of the trimming process, resulting in highly accurate and stable thin film processing with reduced line edge roughness and line width roughness.
Implementation Method 1
generating a plasma of the first processing gas in the processing space by applying a radio frequency power to the first electrode or the second electrode
Implementation Method 2
a plasma is generated by a high frequency discharge between the electrodes
Implementation Method 3
applying a negative DC voltage to the first electrode exposed to the plasma of the second processing gas, thereby accelerating electrons from the first electrode into the resist pattern
Implementation Method 4
electrons discharged from the first electrode are injected into the resist pattern on the substrate to thereby improve an etching resistance of the resist pattern
Data Source
AI summary
A plasma etching method includes disposing first electrode and second electrodes; preparing a part in a processing chamber; supporting a substrate by the second electrode to face the first electrode; vacuum-evacuating the processing chamber; supplying a first processing gas containing an etchant gas into a processing space between the first electrode and the second electrode; generating a plasma of the first processing gas in the processing space by applying a radio frequency power to the first electrode or the second electrode; and etching a film on the substrate by using the plasma. Further, a resist modification process includes vacuum-evacuating the processing chamber; supplying a second processing gas into the processing space; generating a plasma; and applying a negative DC voltage to the part, the part being disposed away from the substrate in the processing chamber and injecting electrons discharged from the part into the resist pattern on the substrate.