Laser Adhesive Removal for Semiconductor Masks
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Solution Overview
Problem
The existing methods for removing the adhesive layer between a mask and a pellicle in semiconductor manufacturing are inefficient and can damage the mask, particularly when using wet chemical processes like sulfuric acid or organic compounds.
Innovation Solution
A device and method utilizing a laser beam to remove the adhesive layer, with controlled wavelength, waveform, and energy density, monitored by an imaging unit to ensure precise and safe removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wet chemical removing method (sulfuric acid or organic chemical) is used to remove mask adhesive, then the adhesive can be removed, but the mask may be damaged and the removing process becomes very difficult
Solution Approach 1:
The patent replaces wet chemical removing methods with a laser-based removing method. The laser beam irradiates the adhesive layer to generate local heating and ablation, effectively removing the adhesive without using corrosive chemicals that can damage the mask. This substitution of chemical process with optical/thermal process eliminates the harmful effect of mask damage while maintaining removal effectiveness.
Solution Approach 2:
The patent controls and optimizes laser parameters including wavelength (193-290 nm), pulse width (10-100 ns), and energy density (25-1000 mJ/cm²) to achieve effective adhesive removal. By precisely adjusting these parameters, the laser energy is concentrated on the adhesive layer to enable selective removal while preventing damage to the mask structure.
2Object-affected harmful factors
If laser beam is irradiated to remove adhesive layer, then the adhesive can be removed with reduced mask damage risk, but excessive irradiation may still damage the mask
Solution Approach 1:
The patent incorporates an imaging unit that monitors the adhesive removal process in real-time. The imaging unit captures images of the adhesive layer before and during laser irradiation, allowing the control unit to adjust laser parameters dynamically based on the actual removal progress. This feedback mechanism prevents excessive irradiation that could damage the mask while ensuring complete adhesive removal.
Solution Approach 2:
The patent uses pulsed laser irradiation with controlled pulse widths (10-100 ns) and repetition rates (10-100 Hz). The periodic pulsing allows the mask to dissipate heat between pulses, preventing thermal accumulation that could cause damage. This periodic action enables effective adhesive removal while maintaining mask integrity.
3Productivity
If conventional wet chemical methods are used, then adhesive removal can be achieved, but the process is time-consuming and complex
Solution Approach 1:
The patent replaces time-consuming wet chemical processes with a rapid laser-based removing method. The laser beam directly ablates the adhesive layer through photodissociation and vaporization, eliminating the need for prolonged chemical soaking and multiple cleaning steps. This substitution reduces the overall removing process duration significantly while maintaining effectiveness.
Solution Approach 2:
The patent utilizes phase transition of the adhesive layer through laser heating. The laser energy rapidly heats the adhesive, causing it to transition from solid to vapor phase through ablation and evaporation. This phase transition occurs much faster than chemical dissolution methods, dramatically improving productivity and reducing process time.
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 laser-based method effectively removes the adhesive layer with reduced risk of damaging the mask, allowing for faster and more controlled processing while preventing excessive irradiation.
Implementation Method 1
a laser irradiating unit configured to irradiate a laser beam to an adhesive layer formed between the mask and the pellicle; a controller configured to control a wavelength, a waveform, and an energy density of the laser beam, so as to remove the adhesive layer through emission of the laser beam
Implementation Method 2
remove the adhesive layer through emission of the laser beam
Data Source
AI summary
Provided is an adhesive removing device for removing an adhesive for adhering a mask and a pellicle from the mask. The adhesive removing device includes: a laser irradiating unit configured to irradiate a laser beam to an adhesive layer formed between the mask and the pellicle; a controller configured to control a wavelength, a waveform, and an energy density of the laser beam, so as to remove the adhesive layer through emission of the laser beam; and an imaging unit configured to monitor a region to which the laser beam is irradiated.