2023 The Complete Guide To Photoresist
Photoresist, also known as photoresist, is a light-sensitive mixed liquid. It consists of photoinitiator, photoresist resin, monomer, solvent and other additives. Photoresist is a kind of graphic transfer medium, which can be used to transfer the mask version graphic to the substrate with different solubility after light reaction. At present, photoresist is widely used in the fabrication of fine graphic lines in the optoelectronic information industry. It is one of the key materials in the field of electronics manufacturing.
According to the wavelength of light, photoresist can be divided into ultraviolet (300-450nm) photoresist, deep ultraviolet (160-280nm) photoresist, extreme ultraviolet (EUV, 13.5nm) photoresist, electron beam photoresist, ion beam photoresist, X-ray photoresist, etc. Generally speaking, the shorter the wavelength, the better the processing resolution under the same process method.
According to the different applications, photoresists can be divided into photoresists for printed circuit boards (PCBs), liquid crystal displays (LCDs), semiconductors and other applications. The technical barriers of PCB photoresists are relatively low compared to the other two categories, while semiconductor photoresists represent the most advanced technology level of photoresists.
By chemical structure; photoresists can be divided into photopolymeric, photolytic, photocross-linked and chemically exaggerated. Photopolymeric photoresists use alkene monomers to generate free radicals under the action of light, which further triggers the polymerization of monomers and finally generates polymers. Photolytic photoresists use diazoquinones (DQN) as photoreceptors, which can be made into positive photoresists by photolytic reaction after illumination; photocross-linked photoresists use polyvinyl laurate as photosensitive materials, which can be made into negative photoresists by forming an insoluble mesh structure under the action of light and resisting corrosion. After the use of deep ultraviolet (DUV) light sources in semiconductor integrated circuit lithography, chemical amplification (CAR) technology has gradually become the mainstream of industry applications. In CAR technology, the resin is a polyethylene that is protected by chemical groups and therefore difficult to dissolve. Chemically amplified photoresists use photoacids (PAGs) as photoinitiators. When the photoresist is exposed, an acid is produced by the PAG in the exposed area. This acid acts as a catalyst during the post-heat baking process and will remove the resin’s protective groups, making the resin readily soluble. Chemically amplified photoresists are 10 times faster than DQN photoresists and have good optical sensitivity to deep UV light sources, high contrast, and high resolution.
Photoresist is an important material for IC manufacturing: the quality and performance of photoresist is a key factor affecting IC performance, yield and reliability, the cost of the photolithography process is about 35% of the entire chip manufacturing process, and takes about 40-50% of the time of the entire chip process, the cost of photoresist accounts for about 4% of the total cost of IC manufacturing materials, the market is huge. According to the third-party institution Wisdom Research Consulting, the global photoresist market size is expected to be nearly $9 billion in 2019, with a CAGR of about 5.4% since 2010 to date. The market is expected to continue to grow at an average annual rate of 5% in the next three years, and the global photoresist market size will exceed USD 10 billion by 2022. The photoresist industry has very high industry barriers, so the industry is an oligopoly situation in the global scope. The photoresist industry has been monopolized by Japanese and American professional companies for many years. At present, the top five manufacturers occupy 87% of the global photoresist market, and the industry is highly concentrated. Among them, the market share of Japan JSR, Tokyo E&C, Japan Shin-Etsu and Fuji Electronic Materials combined reaches 72%. And the core technology of high-resolution KrF and ArF semiconductor photoresists is basically monopolized by Japanese and American companies, and most of the products come from Japanese and American companies, such as DuPont, JSR Corporation, Shin-Etsu Chemical, Tokyo Chemical Industry, Fujifilm, and Korea Dongjin. The whole photoresist market pattern, Japan is the giant gathering place of photoresist industry. At present, mainland China is highly dependent on foreign countries for electronic materials, especially photoresists. Therefore, it is an inevitable trend to replace the domestic production in semiconductor materials.