Research Devices MAS-500B IR Visible Mask Aligner Wafer Alignment System

Research Devices MAS-500B IR Visible Mask Aligner Wafer Alignment System

The Research Devices MAS-500B is an Infrared/Visible Mask Aligner designed for front-to-back alignment of semiconductor wafers. It operates across a wavelength range of 0.4 to 1.8 microns, enabling alignment in both IR reflection and IR transmission modes. The system allows an operator to simultaneously view a pattern on an inverted wafer and the corresponding pattern on a mask, making precise front-to-back registration possible through near-infrared illumination.

Specifications & What's Included

• Manufacturer: Research Devices
• Model: MAS-500B
• Type: Infrared/Visible Mask Aligner
• Operating wavelength range: 0.4 – 1.8 microns (near infrared to visible)
• Alignment modes: IR reflection, IR transmission, and reflection/transmission combination
• Power: 110V AC
• Air supply: 40 – 100 PSI
• Control console with front-panel push-button controls included
• Optical column and wafer stage assembly
• Operator manual included

Applications

The MAS-500B was developed for photolithography process steps that require precise alignment between features on opposite sides of a semiconductor wafer — a technique commonly called front-to-back or backside alignment. Many compound and elemental semiconductor materials, including silicon, gallium arsenide, cadmium telluride, and indium phosphide, are transparent in the near-infrared range. This transparency makes it possible to illuminate an inverted wafer with IR light and simultaneously image both the front-side wafer pattern and the mask pattern underneath, allowing the operator to overlay them with high precision before exposure. The IR transmission mode offers high contrast for most standard mask materials, while the reflection mode is especially useful when working with materials such as iron oxide masks that are themselves transparent in the near IR — in that case, a reflection or combined reflection/transmission approach is used to make the mask features visible. Equipment of this type was a staple of compound semiconductor research and production facilities from the 1970s through the 1990s and continues to be used in research labs, university cleanrooms, and specialty semiconductor fabs where compound semiconductor or MEMS device work demands backside alignment capability that standard UV contact aligners cannot provide.