Film Photomask is a master plate used for integrated circuit wafer manufacturing, carrying relevant information of the integrated circuit design layout. In the wafer manufacturing process, the pattern on the Film Photomask is transferred to the exposed substrate material through a series of processes such as photoresist coating, exposure, and development to achieve pattern transfer.
The light is diffracted through the transparent part of the Film Photomask, and the light intensity will diverge to the nearby opaque area. The projection lens collects these rays and converges the light to project onto the surface of the wafer for imaging. If you want to distinguish two adjacent transparent apertures on the Film Photomask, the light intensity of the dark area between them must be much smaller than the light intensity of the transparent area. This pursuit of high resolution is not only reflected in the continuous improvement of the light source wavelength and photoresist, but also in the continuous updating of the types of photomasks and the materials used.
The current photomasks used in semiconductor manufacturing mainly include binary Film Photomask, phase-shift Film Photomask, and EUV Film Photomask.
Synthetic quartz is prepared by gas phase axial deposition. It is a block of quartz glass formed by a series of chemical reactions in a hydrogen-oxygen flame to generate silicon dioxide particles. Among them, the silicon compound can be SiCl4, SiHCl3, SiH2Cl2 or even SiH4. Synthetic quartz must have high light transmittance of more than 99%, strong light resistance, low thermal expansion rate, high quality, high flatness, high surface accuracy, strong plasma resistance and acid and alkali resistance, high insulation and other characteristics.
Film Photomask substrate, also known as blank photomask substrate, refers to a quartz substrate on which functional materials such as Cr and MoSi have been deposited, and then anti-reflective coating and photoresist are deposited. After exposure, etching, stripping, cleaning, inspection and other processes, Film Photomask is prepared. Film Photomask substrate accounts for about 90% of the raw material cost of Film Photomask products and is a key factor in the cost of Film Photomask products. As Film Photomask users continue to increase their requirements for the quality of their final products, Film Photomask companies are constantly pursuing breakthroughs in product quality, and the quality of Film Photomask substrates has a significant impact on the quality of Film Photomask final products. The key indicators of Film Photomask substrates include flatness, performance and thickness of surface deposited materials, cleanliness, etc. As the technology nodes of integrated circuit manufacturing continue to shrink, the requirements for these technical indicators are becoming more and more stringent.
Film Photomask protective film is a 1µm thick transparent film pasted on an aluminum alloy frame. The use of Film Photomask protective film has two main functions. One is to ensure that dust or particles attached to the Film Photomask will not be imaged on the chip during the exposure process; the other is to maintain the cleanliness of the photomask, reduce the wear of the Film Photomask during use, and improve the production efficiency of semiconductor manufacturing.
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