Photoresist is an organic polymer which becomes soluble when exposed to ultraviolet light. It contains a light-sensitive substance whose properties allow image transfer onto a PCB board. It is used in many applications within various industries such as semiconductor, biomedical engineering, holographic, electronics, and nanofabrication. As an example, photoresist is used to help define circuit patterns during chip fabrication in the semiconductor industry. Using photoresist prevents etching or plating of the area it covers (this is also known as resist).

International Light supplies several instruments to assist in the measurement of Photoresist "A" (wide) response and Photoresist "B" (narrow) response. Consult your photoresist manufacturer to determine whether the 'A' or 'B' response is appropriate for your application.

Unique to our radiometer systems is the ability to autorange during exposure integrations. Our proprietary floating current-to-current amplification technology permits autoranging without any gain changes, for real-time integration without data loss.

The IL1440-A Photoresist Radiometer system was designed for direct measurement of the UV and blue visible irradiance used for exposing photoresist coated substrates in test and production environments. The low profile (12.5 mm high) XRL probe can be placed right inside most exposure systems.

The IL1740-A Photoresist Research Radiometer provides unmatched versatility and power for photoresist research. Interchangeable filters and multiple sensitivity factors, as well as a variety of I/O options, makes this system ideal for researchers and development engineers of photoresist equipment.

The IL1440-B Photoresist Radiometer and the IL1740-B Research Radiometer systems employ UV filtering designed specifically for photoresist applications requiring a peak sensitivity in the UVA and subdued response in the blue. The 'B' response is also useful for isolating the 365 mm mercury line.


The IL1741 and IL1441 Photoresist Radiometer systems include the new "Super Slim" UV Probe, for use in very low profile applications, such as printed circuit board and printing plate exposure assemblies. The probe is a mere 2 mm thick, the thickness of a printed circuit board.

The "Super Slim" probe offers broad UV sensitivity from 260 nm to 400 nm. Since Mylar and glass do not transmit UV below 320 nm, the use of these materials in vacuum chambers blocks UVB, creating an effective spectral response quite similar to the IL1740-B response.