Plasma Processing Apparatus Electrode Spacing for Resist Mask Transcription
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Solution Overview
Problem
In semiconductor manufacturing, the miniaturization of patterns on target objects and the need to reduce non-uniformity in pattern dimensions require improved transcription accuracy of resist masks onto hard masks, which is hindered by the low etching resistance of conventional resist masks against etchant gases and plasmas.
Innovation Solution
A method involving exposure of resist masks to hydrogen active species generated by exciting plasma of a hydrogen-containing gas, followed by etching of the hard mask layer in a plasma processing apparatus, where the distance between electrodes is adjusted to enhance the exposure and etching processes, improving dimensional accuracy and maintaining resist mask thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the resist mask is exposed to hydrogen active species to improve dimensional accuracy, then the transcription accuracy improves, but the curing process time increases
Solution Approach 1:
The patent changes the physical parameters of plasma exposure by adjusting hydrogen gas flow rate, plasma power, and exposure time to optimize the curing process. By controlling these parameters, the patent achieves adequate resist mask curing with reduced exposure time, resolving the contradiction between transcription accuracy and process time
Solution Approach 2:
The patent applies preliminary hydrogen plasma exposure to the resist mask before the main etching process. This preliminary action pre-cures the resist mask, improving its dimensional stability and transcription accuracy during subsequent etching, while the pre-treatment approach reduces the total time required during critical etching steps
2Manufacturing precision
If the plasma exposure time is increased to improve curing, then the dimensional accuracy improves, but the etching resistance decreases
Solution Approach 1:
The patent optimizes plasma exposure parameters including hydrogen gas flow rate (5-50 sccm), plasma power (50-500 W), and exposure time (1-60 seconds) to achieve the desired balance. By carefully controlling these parameters, the patent cures the resist mask sufficiently to improve dimensional accuracy while preventing excessive exposure that would compromise etching resistance
Solution Approach 2:
The patent applies a controlled amount of hydrogen plasma exposure that is sufficient to cure the resist mask and improve dimensional accuracy, but deliberately limited to avoid excessive exposure. This partial action approach ensures adequate curing while preserving the etching resistance needed for the subsequent hard mask etching process
3Productivity
If the distance between upper electrode and mounting table is reduced to enhance plasma exposure, then the curing efficiency improves, but the etching uniformity deteriorates
Solution Approach 1:
The patent employs dynamic adjustment of the distance between the upper electrode and mounting table based on the processing step. During hydrogen plasma exposure, the distance is reduced to enhance curing efficiency. During subsequent etching processes, the distance is increased to improve etching uniformity. This dynamic repositioning resolves the contradiction between curing efficiency and etching uniformity
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 enhances the transcription accuracy of resist masks onto hard masks, reduces non-uniformity in pattern dimensions, and shortens the curing process time, thereby minimizing the impact of long etching times on the hard mask layer.
Implementation Method 1
exposing the resist mask to active species of hydrogen generated by exciting plasma of a hydrogen-containing gas
Implementation Method 2
by exposing the resist mask to the active species of hydrogen, the resist mask can be modified, that is, hardened
Implementation Method 3
etching the hard mask layer by exciting plasma of an etchant gas within the processing vessel
Implementation Method 4
The plasma of the hydrogen-containing gas and the plasma of the etchant gas are excited by generating a high frequency electric field between an upper electrode and a lower electrode
Data Source
AI summary
A method of processing a target object includes (a) exposing a resist mask to active species of hydrogen generated by exciting plasma of a hydrogen-containing gas within a processing vessel while the target object is mounted on a mounting table provided in the processing vessel; and (b) etching a hard mask layer by exciting plasma of an etchant gas within the processing vessel after the exposing of the resist mask to the active species of hydrogen. The plasma is excited by applying of a high frequency power for plasma excitation to an upper electrode. In the method, a distance between the upper electrode and the mounting table in the etching of the hard mask layer ((b) process) is set to be larger than a distance between the upper electrode and the mounting table in the exposing of the resist mask to the active species of hydrogen ((a) process).