Application of photoinitiator and photoresist in semiconductor industry

Photoresist is a mixture of liquid sensitive to light. Photoresist components include: photoinitiator (including photosensitizer, photoacid producing agent), photoresist resin, monomer, solvent and other auxiliaries. Photoresist can transfer the required fine graphics from the mask to the substrate to be processed through photochemical reaction, exposure, development and other lithographic processes. The substrate to be machined here can be integrated circuit material, display panel material or printed circuit board, depending on the application scenario. Photolithography can be divided into PCB photolithography, display panel photolithography, semiconductor photolithography and other photolithography according to the application field.

Benefiting from the trend of semiconductor, display panel and PCB industries moving eastward, the growth rate of China's local photoresist supply has reached 11% since 2011, higher than the global average growth rate of 5%. In 2019, the sales scale of local enterprises in China's photoresist market was about 7 billion yuan, accounting for about 10% of the global market, with huge development space. At present, China's local photoresist mainly PCB photoresist, flat panel display, semiconductor photoresist supply accounted for a very low proportion. Photoresist is an important material in integrated circuit manufacturing. The quality and performance of photoresist are the key factors that affect the performance, yield and reliability of integrated circuits. The photolithography process costs about 35% of the entire chip manufacturing process and takes about 40-50% of the time of the entire chip manufacturing process. Photoresist materials account for about 4% of the total cost of IC manufacturing materials. Therefore, photoresist is the core material of semiconductor integrated circuit manufacturing.

After the use of deep ultraviolet (DUV) light source in semiconductor integrated circuit lithography, chemical amplification (CAR) technology has gradually become the mainstream of industry applications. In chemical amplification photoresist, the resin is polyethylene protected by chemical groups and thus difficult to dissolve. Chemical amplified photoresist uses a photoacidogenic agent (PAG) as a photoinitiator.