Pulsed VUV Light Source for SAM Patterning
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Solution Overview
Problem
Vacuum ultra violet (VUV) light irradiation in atmospheric air leads to ozone generation, causing oxidative decomposition reactions that result in enlarged etching widths and pattern defects in self-assembled monolayers (SAMs) due to the inability to effectively suppress ozone etching during patterning processes.
Innovation Solution
A VUV light source device emitting pulsed light with a duty ratio of 0.00001 to 0.01, combined with a flash lamp having an arc tube with a xenon gas and a short inter-electrode distance, and a light irradiation device with an inert gas-purged enclosure to minimize ozone generation and promote oxidative decomposition reactions in the presence of oxygen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If VUV light is emitted in atmospheric air, then oxygen is activated for oxidative decomposition reactions, but ozone is generated causing enlarged etching widths and pattern defects
Solution Approach 1:
The patent applies periodic pulsed light emission with duty ratios of 0.00001 to 0.01, where the light is emitted in short bursts followed by longer intervals. This periodic action allows oxygen activation during the pulse for decomposition reactions while the intervals permit ozone decomposition, thereby maintaining patterning speed while improving pattern resolution by reducing ozone-related defects
Solution Approach 2:
The patent changes the temporal parameters of light emission by controlling the duty ratio within the range of 0.00001 to 0.01. This parameter change transforms continuous light emission into pulsed emission, enabling dynamic control over the balance between oxygen activation (for productivity) and ozone accumulation (for precision), thus resolving the contradiction between patterning speed and pattern resolution
2Illumination intensity
If conventional lamps with long light emitting length are used, then sufficient VUV light intensity is achieved, but light wraparound occurs limiting pattern line width to approximately 100 μm
Solution Approach 1:
The patent extracts only the essential function of VUV light emission while eliminating the harmful wraparound effect by using a flash lamp with sufficiently short light emitting length. This extraction approach selects a light source that provides adequate VUV intensity for oxygen activation while its compact size prevents light wraparound, enabling pattern line widths finer than 100 μm without sacrificing illumination intensity
3Manufacturing precision
If pulsed light with very low duty ratio is used to suppress ozone generation, then pattern resolution improves, but total light energy delivered decreases
Solution Approach 1:
The patent optimizes the duty ratio parameter within the specific range of 0.00001 to 0.01, finding the optimal balance point where pulsed emission sufficiently suppresses ozone generation for improved pattern resolution while maintaining adequate total light energy delivery for effective oxygen activation and decomposition reactions
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 solution effectively suppresses ozone generation and etching, enabling precise patterning of SAMs with improved resolution and reduced defects by converting oxygen into active species for enhanced decomposition reactions.
Implementation Method 1
emits, as the light containing vacuum ultra violet light, light that is pulsed light and has a duty ratio of light emission equal to or greater than 0.00001 and equal to or less than 0.01
Implementation Method 2
suppress an amount of ozone generated with an oxygen molecule in an atmosphere containing oxygen, such as an atmospheric air, absorbing ultra violet light
Implementation Method 3
By combining the above mentioned flash lamp with a paraboloid mirror to be used, it makes it possible to achieve a light source device that is capable of extracting light that is the VUV light and also parallel or substantially parallel light
Implementation Method 4
focuses attention on the oxidative decomposition removal reaction of the SAM with the VUV light
Implementation Method 5
converting oxygen into active species for enhanced decomposition reactions
Implementation Method 6
the VUV light only performs the direct decomposition (dissociation) of the SAM
Data Source
AI summary
Disclosed herein a vacuum ultra violet light source device that is capable of suppressing an amount of ozone generation when the vacuum ultra violet light is emitted into an atmosphere containing oxygen, a light irradiation device incorporating the vacuum ultra violet light device, and a method of patterning a self-assembled monolayer employing the light irradiation device. The light irradiation device is configured to irradiate a self-assembled monolayer (SAM) formed on a workpiece with light containing vacuum ultra violet light through a mask M on which a prescribed pattern is formed so as to perform a patterning process of the SAM. The light containing the vacuum ultra violet light to be irradiated onto the SAM is light that is pulsed light and has a duty ratio of light emission equal to or greater than 0.00001 and equal to or less than 0.01.