ASML IR1-NIR Module 4022.639.86644 (ELEC‑I‑1001=8F25)

General Description

The ASML IR1-NIR module, part number 4022.639.86644 (also designated ELEC‑I‑1001=8F25), is an optoelectronic sensor assembly that operates in the infrared (IR) and near‑infrared (NIR) spectral bands. It is used in advanced photolithography systems for non‑contact wafer alignment, overlay measurement, and film thickness monitoring. The module combines a broadband IR source, a tunable filter, and a high‑sensitivity detector in a compact housing.

Optical and Electrical Specifications

• Wavelength Range: 900 nm – 1700 nm (NIR) and 3 – 5 µm (IR)

• Source Type: Tungsten‑halogen lamp with 5000 hour lifetime

• Detector: InGaAs photodiode (NIR) and thermopile (IR), each with preamplifier

• Filter Tunability: Motorized grating monochromator, resolution 2 nm

• Output Signal: 0‑10 V analog, 16‑bit digital via SPI

• Supply Voltage: 24 V DC @ 1.2 A (includes lamp driver)

• Optical Input: SMA‑905 connector for fiber‑coupled measurement

• Dimensions: 150 mm x 80 mm x 60 mm

Functional Principle

The IR1-NIR module operates in transmission or reflection mode. In alignment applications, the IR beam is directed through the wafer’s silicon substrate, which is transparent at NIR wavelengths. The transmitted light is collected by a detector array, and the resulting intensity pattern reveals the position of buried alignment marks. For film thickness measurement, the module uses interferometric reflectance; the reflected spectrum is analyzed to compute the thickness of photoresist or oxide layers with sub‑nm precision. The built‑in monochromator allows the system to select the optimal wavelength for each measurement.

Integration with ASML Systems

The module communicates with the system controller via a dedicated interface board using a 50‑pin ribbon cable. The analog outputs are connected to the main data acquisition card, while the SPI bus provides digital readout and filter position feedback. The module is typically mounted on the metrology frame above the wafer stage, with optical fibers routed to the measurement head. A calibration routine is executed at system start‑up, using a reference mirror to normalize the detector response.

Installation and Calibration

Mount the module on a vibration‑isolated bracket using the three M5 threaded holes. Connect the power cable, the analog interface, and the SPI cable. Insert the fiber optic cable into the SMA connector and secure it with the thumbscrew. After power‑up, the module performs a self‑calibration: it sweeps the monochromator from 900 nm to 1700 nm and records the baseline spectrum. This baseline is stored in the module’s EEPROM. For field calibration, a certified reflectance standard is measured; the system software adjusts the gain coefficients accordingly. Calibration should be repeated every three months or whenever the lamp is replaced.

Maintenance and Troubleshooting

The lamp has a typical lifetime of 5000 hours; the system tracks the operating hours and alerts the user when replacement is due. To replace the lamp, power off the module, remove the four screws on the top cover, and swap the lamp cartridge. Avoid touching the new lamp with bare fingers; use a lint‑free cloth. The detector window should be cleaned with lens tissue and methanol annually. Common fault symptoms: low signal (check lamp and fiber connection), noisy output (check grounding and cable shielding), and filter jamming (lubricate the monochromator worm gear with a small amount of PTFE grease). If the SPI communication fails, verify the cable continuity and the Vcc level.

Ordering and Compatibility

This module is compatible with ASML systems that support the ELEC‑I‑1001 interface. The part number 4022.639.86644 includes the complete assembly with lamp, monochromator, and detector. Replacement lamps and fiber cables are available as separate items. When ordering, specify the same revision to ensure firmware compatibility.