The Effect of X-ray Irradiation on the Photoresist with Novella Resin

As a result of the rapid development of lithography, it enables semiconductor technology to design more devices in the same area, which therefore makes electronic products faster and more functional, and holds more components. The photoresist, playing an important role in lithography, constantly develops with light wavelength used for exposure from early entire wavelengths to present optical and non-optical lithography. The light sources of optical lithography have moved from the early 436 nm and 365 nm wavelengths to short-wavelength light gradually. It is a big issue to find a suitable photo resist under the exposure of 0.578 nm X-Ray light source. In this paper we first proposed to use DNQ /Novolak photo resist sold in the market for the 0.578 nm X-Ray lithography. In the experiment, it is discovered that the exposure amount of X-Ray can determine if the photoresist is positive or negative type, in low doses, when the photoresist film thickness is increased with the reduced exposure time until a critical level is reached, the Novolak liquid will become positive photo resist after it is exposed in certain time. The high-dose X-Ray beam will make Novolak resin bond break and result in free radicals, which, through resin cross linking, can improve the internal strength and reduce developer solubility so the Novolak liquid can become a negative photoresist. By using synthesized DNQ/Novolak photoresist under X-Ray exposure, we can reduce the process line width, and explore principles of photo resist imaging analysis under the different exposure doses.