LITHOPROTECT^® YELLOW LIGHT PRODUCTS

Requirements for suitable yellow films

The spectral sensitivity of most photoresists is not only in the near ultraviolet (wavelengths > 320 nm) spectral range, but also extends into the visible range of the spectrum. Even at 435 nm (g-line), most photoresists still absorb very strongly and this absorption lies in the middle of the blue range of the spectrum and falls off towards longer wavelengths without a sharp edge.
In order to ensure that a coated substrate can be exposed to yellow light for several hours without the resist layer being exposed unintentionally, wavelengths < 500 nm must be blocked below the detection limit by appropriate optical filters (yellow film) .
At the same time, yellow films should be as transparent as possible above a wavelength of 540 nm, i.e. in the range of the sensitivity maximum of the human eye. With these conditions, a yellow space can be brightly illuminated with reasonable energy expenditure without influencing the photoresist processing .

Lithoprotect^_® Properties

Lithoprotect^_® UV protection products have been specially developed for UV photosensitive applications and reliably block UV radiation below 520 nm. Lithoprotect^_® UV protection products are made of yellow through-coloured cellulose triacetate. Due to the through-colouring, reliable UV protection below 520 nm can be guaranteed even for demanding applications. The UV blocking filter is used in photolithography, printed circuit board and microelectronics production, printing plate and photoresist production as well as when handling photoresists and diazo films. Our films are even used in pharmaceutical research, development and production.
The Lithoprotect^_® yellow film Y520 is waterproof and resistant to oils, greases, petrol and aliphatic hydrocarbons. The yellow film is dissolved or swollen by chlorinated hydrocarbons, ketones and aromatic solvents. This can impair the optical properties. The UV protection film is not resistant to concentrated acids and alkalis. The film is attacked in these substances.

Lithoprotect^_® Areas of application

Lithoprotect^_® UV protection yellow film Y520 can be processed like paper. It can be applied to windows, privacy screens, room dividers, lamps and in front of openings using double-sided adhesive tape. For large window applications, we recommend our Lithoprotect^_® UV protection yellow film YSA520 self-adhesive. The Lithoprotect ^_® UV protection yellow film YSA520 self- adhesive can be applied easily and bubble-free to any smooth and solid surface using the mounting fluid DXMF301.

For filtering fluorescent tubes, durXtreme offers you special polycarbonate sleeves (Y520 T5 and Y520 T8) into which the Lithoprotect^_® UV blocking filter is incorporated, allowing you to produce UV-free light sources (yellow light) from normal fluorescent tubes at low cost.

We recommend the Lithoprotect^_® products for filtering short-wave radiation for the processing of photochemicals, which are divided into film (self-adhesive and non-self-adhesive) and sleeves for fluorescent tubes fitted with filter film.

The listed Lithoprotect^_® products are available from our partner company durXtreme GmbH.