Excimer lasers interact with their surrounding system through electrical, optical, thermal and gas interfaces. Stable operation requires that these interfaces meet defined engineering constraints.
The specifications and integration parameters described in this section refer to standard MLI compact excimer laser systems.
Integrating an excimer laser into a system requires more than electrical connection and beam delivery. Process stability and performance depend on how well supporting systems such as gas handling, cooling, and optics are aligned with the laser’s operating conditions.
This section provides a structured overview of the most relevant integration parameters and checks. It connects system requirements with real-world operation, helping to ensure reliable performance from initial setup through continuous use.
Material processing with excimer lasers depends on fluence (energy per area) delivered to the surface.
Fluence equation
Where:
Example (MLI lasers)
Typical beam dimensions:
6 mm × 3 mm
Beam area:
A = 0.6 × 0.3 = 0.18 cm²
Pulse energy:
7 mJ = 0.007 J
Result:
Excimer material processing typically occurs between:
0.05 – 2 J/cm²
depending on wavelength and material.
Excimer processing often uses mask projection optics.
The projected feature size depends on the optical demagnification ratio.
Projection equation
Where
M = projection magnification
Typical projection ratios: 0.1 – 0.5
Example
Mask opening: 1 mm
Projection ratio: 0.2
Feature size: 200 µm
Beam divergence determines beam expansion along the optical path.
Beam expansion
Where
D₀ = initial beam size
θ = divergence angle
z = propagation distance
MLI beam parameters
| Parameter | Value |
| Beam size | 6 × 3 mm |
| Beam divergence | 2 × 1 mrad (FWHM) |
Example
Distance: 500 mm
Vertical divergence: 2 mrad
Beam expansion: 0.002×500mm=1mm
This must be considered when placing:
Deep UV radiation is strongly absorbed by oxygen and contaminants.
For 193 nm, beam paths should be nitrogen purged.
Purge gas requirement
| Parameter | Specification |
| Gas | Nitrogen |
| Purity | ≥ 5.5 |
Purpose
For 248 nm, purging the beam paths is not considered mandatory.
| Parameter | Standard configuration | High power configuration |
| Supply voltage | 230 V | 230 V |
| Frequency | 50/60 Hz | 50/60 Hz |
| Power consumption | ≤ 2 kVA | ≤ 2.3 kVA |
| Connector | IEC 60320 C14 | IEC 60320 C14 |
Stable grounding and low electrical noise improve discharge stability.
Air cooling
| Parameter | Value |
| Airflow | 400 m³/h |
| Exhaust hose diameter | 158 mm |
Duty cycle limits (air cooled)
| Max. Repetition Rate | Duty cycle |
| 200 Hz | 100 % |
| 500 Hz | 40 % (max 10 min) |
| 1000 Hz | 20 % (max 5 min) |
Water cooling
Water cooling enables continuous 100% duty cycle operation.
| Parameter | Requirement |
| Flow rate | ≥ 2 l/min |
| Cooling capacity | ≥ 1000 W |
| Temperature stability | ±2 °C |
| Supply temperature | 30 – 40 °C |
| Pressure | < 5 bar |
Laser tube parameters
| Parameter | Value |
| Tube volume | 6.5 l (standard) |
| Tube volume HP | 6.3 l |
| Operating pressure | 5 – 6 bar @20°C |
Gas inlet pressures
| Gas | Pressure |
| Premix | 7 – 9 bar absolute |
| Flush gas | 1.5 – 3 bar absolute |
Connectors
Excimer lasers require precisely defined gas mixtures to ensure stable discharge behavior and consistent output performance. Gas quality and purity have a direct impact on lifetime and stability. For optimal results, MLase provides recommendations on qualified gas sources.
ArF mixture (193 nm)
| Component | Fraction | Purity |
| F₂ | 0.133 % | 2.8 |
| Ar | 1.80 % | 5.5 |
| Ne | balance | 4.8 |
KrF mixture (248 nm)
| Component | Fraction | Purity |
| F₂ | 0.150 % | 2.8 |
| Kr | 1.25 % | 5.5 |
| He | 2.534 % | 6.0 |
| Ne | balance | 4.8 |
Service gases
| Application | Gas | Purity |
| Optics exchange | Helium | 5.0 |
| Beam path purge | Nitrogen | 5.5 |
Optics lifetime
| Laser | Energy | Typical Lifetime |
| ArF | 4–6 mJ | 500 – 1000 million pulses |
| ArF HP | 8 mJ | 300 – 600 million pulses |
| KrF | 7 mJ | 500 – 1500 million pulses |
| KrF HP | 12 mJ | 300 – 700 million pulses |
Active gas lifetime
| Laser | Energy | Typical Lifetime |
| ArF | 4 mJ | 50 – 80 million pulses |
| ArF | 6 mJ | 30 – 50 million pulses |
| ArF HP | 8 mJ | 20 – 40 million pulses |
| KrF | 7 mJ | 60 – 90 million pulses |
| KrF HP | 12 mJ | 30 – 50 million pulses |
Additional component lifetimes
| Component | Typical Lifetime |
| Laser tube | 2 – 4 billion pulses |
| High voltage circuitry | 4 – 8 billion pulses |
| Electronics | 4 – 10 billion pulses |
| Gas filter | ~200 gas exchanges |
Passive gas lifetime
| Condition | Typical Lifetime |
| Idle gas stability | 1–3 months |
MLase excimer lasers are designed for modular service and low field service requirements. A defined consumables concept and exchange tube architecture allow replacement of lifetime-limited components, avoiding full system replacement and reducing operational downtime.
Operating effort in excimer systems primarily scales with total pulse count. Over time, generated pulses directly determine gas consumption, optics degradation and component replacement intervals.
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