56mm Beam Splitter Double Prism Optical Assembly Mask Aligner Lithography

56mm Beam Splitter Double Prism Optical Assembly Mask Aligner Lithography

This is a 56mm beam splitter double prism optical assembly designed for use in mask aligner and photolithography systems. The assembly consists of two bonded prism elements housed in a black anodized metal frame with a stainless steel cylindrical top mount featuring three threaded holes. Circular apertures are cut into opposing faces of the housing, allowing light to pass through the prism stack. Multiple optical coatings are visible on the prism faces — pale blue, amber/yellow, and pink/red — consistent with multi-layer UV and visible-spectrum anti-reflection or beam-splitting coatings used in lithography illumination optics.

Specifications & What's Included

• Type: Beam splitter / double prism optical assembly
• Aperture size: 56mm
• Housing: Black anodized metal frame
• Top mount: Stainless steel cylindrical mount with 3 threaded holes
• Aperture style: Circular aperture on two opposing faces
• Prism configuration: Two bonded prism elements (double prism / beam splitter cube)
• Optical coatings: Multi-layer coatings visible — pale blue, amber/yellow, and pink/red on respective faces
• Condition: Sold AS-IS — unable to test; see condition block below
• Includes: Optical prism assembly only — no mounting hardware, cables, or system components

Applications

Beam splitter prism assemblies of this type are core optical components in mask aligner and contact/proximity photolithography systems used in semiconductor wafer fabrication and MEMS manufacturing. In a mask aligner, the beam splitter divides and redirects UV illumination — typically from a mercury arc lamp — to expose photoresist on a wafer through a patterned photomask. The double-prism (cube) configuration splits or combines beams at a defined ratio while the multi-layer coatings optimize transmission and reflection at the specific UV wavelengths used in lithography (commonly 365nm i-line, 405nm h-line, or 436nm g-line). Equipment of this type was central to the production of integrated circuits, MEMS devices, and flat-panel display substrates from the 1970s through to the present day, and is found in systems such as those manufactured by Karl Suss (SUSS MicroTec), Canon, Nikon, and similar mask aligner platforms. Replacement or spare optical subassemblies like this one are sought by labs maintaining older mask aligner systems where original parts are no longer commercially available.