UV wide spectrum photoresist：High pressure mercury lamp full spectrum exposure; Suitable for process line widths above 2um; Main applications: discrete devices, LED devices, MEMS (Micro Electro Mechanical), advanced packaging.

• characteristic：Using phenolic resin as the film-forming resin and diazonaphthoquinone compound as the photosensitive material, the resolution is relatively low (>5um), the process tolerance is large, and the wet etching resistance is excellent.

G-line photoresist：436nm wavelength ultraviolet exposure light source; Suitable for process line widths above 0.5um; Main applications: LCD、 Discrete components, LED devices, integrated circuits, advanced packaging.

• Features: Phenolic resin is used as the film-forming resin, diazonaphthoquinone compound is used as the photosensitive material, with strong absorption at 436nm and a resolution of about 1.0um. Compared with UV broad-spectrum photoresist, G-line photoresist has larger exposure latitude (Exposure Latitude L) and depth of focus (DOF), better etching resistance, and stricter control of metal ion content due to changes in exposure mode.

I-line photoresist：365nm wavelength ultraviolet exposure light source; Suitable for 0.5-0.35um and 0.25um process line widths; Main applications: integrated circuits, LED devices, advanced packaging.

• Features: Phenolic resin is used as the film-forming resin, diazonaphthoquinone compound is used as the photosensitive material, and the photosensitive agent has strong absorption at 365nm. I-line photoresist can be divided into three categories: one is ordinary I-line photoresist with a resolution of 0.5um, used for non critical layer lithography processes; The second is high-resolution I-line photoresist with a resolution of 0.35um, which is used in key layer lithography processes. The application of chemical amplification type I-lines can increase the resolution to 0.25um; The third is thick film photoresist (with a film thickness of (3-5um), used for passivation layer lithography process. Some special processes require a film thickness of up to 8um.

KrF photoresist：KrF excimer laser light source; Suitable for 0.25-0.13um and 0.11um; Main application: Integrated circuits.

• characteristic：KrF photoresist is the first photoresist to use chemical amplification technology, using poly (p-hydroxystyrene) and its derivatives as film-forming resins, and sulfonium or sulfonium salts as photo induced acid generators. Due to the use of chemical amplification technology, the photosensitive rate is fast (30-50mj) and the resolution is high, which can be applied to 0.25-0.13um process line widths. Combined with Resolution Enhancement Technique (RET), it can be further applied to process linewidths ranging from 0.11um to 90nm.

ArF（193nm）photoresist：Divided into dry ArF photoresist and ArFi immersion photoresist; Dry type is suitable for 130-65nm, ArFi immersion type is suitable for 45-7nm; Main application: Integrated circuits.

• Features: ArF photoresist adopts chemical amplification technology, using polyester cyclic acrylic ester and its copolymers as film-forming resins, and sulfonium or sulfonium salts as photo induced acid generators. ArF dry photoresist applied to 90-65nm process line width; ArFi immersion exposure technology fills water between the lens and photoresist, utilizing the high refractive index of water to improve the resolution of the photolithography process. ArFi immersion photoresist requires corresponding calibration in the presence of photo acid generators and additives, and a top coating is used to prevent the components in the photoresist from being dissolved by water during application. Immersion lithography technology, assisted by phase-shifting photomask, optical proximity effect correction and other resolution enhancement techniques, combined with multiple exposure technology, can be applied to 45-7m process linewidth.

EUV photoresist：13.5nm wavelength extreme ultraviolet exposure light source; Suitable for 7nm and below; Main application: Integrated circuits.

• Characteristics: There are currently three types of EUV photoresist in the research and development stage: (1) traditional chemical amplification. This type of lithography has the characteristic of high light sensitivity and is suitable for EUV lithography technology where the exposure power is limited by the light source capability. However, there are problems such as blurred boundaries between the exposed and non exposed areas caused by acid diffusion, and difficulty in meeting the requirements for resolution and line width roughness. (2) Molecular glass type. This type of photoresist tape is a small molecule organic material with protective groups. This material can be prepared into uniform and disordered amorphous thin films using spin coating technology. The film needs to have a certain degree of thermal stability (Tg of about 150 ° C). However, molecular glass materials tend to collapse and deform severely when the line width decreases, making it difficult to achieve higher resolution. (3) Metal oxide type. This photoresist has a high density and EUV absorption cross-sectional area, with low gas release during exposure and no pollution to optical components. The material itself has excellent etching resistance during pattern transfer, but requires a high exposure energy density.

New photoresist

• Electron beam photoresist: As the name suggests, electron beam photoresist is a photoresist used for electron beam direct writing, mainly composed of poly (methyl methacrylate). This type of photoresist can undergo chain breakage reaction under electron beam bombardment, generating substances that are easily soluble in the developing solution and achieving patterning. Electron beam has fine spots, short wavelengths, and concentrated energy, which can achieve extremely high resolution. It is used for the production of photomasks, but is limited by the slow speed of electron beam direct writing and is not suitable for the production of large-scale integrated circuit chips. Currently, research on multi beam electron beam lithography technology is being carried out internationally in order to improve the production capacity of electron beam lithography. Therefore, although electron beam photoresist is an early developed product, it is still classified as a new type of photoresist here.

• Nanoimprint photoresist: Nanoimprint photoresist mainly includes two types: thermosetting and UV curable. Thermosetting nanoimprint photoresist defines the pattern with the help of an imprint template and is heated and cured. After cooling and demolding, the pattern is transferred to the substrate through etching; UV curable nanoimprint photoresist defines the pattern using a transparent quartz imprint template, and solidifies the photoresist pattern through UV irradiation. After demolding, the pattern is transferred to the substrate through etching. Nanoimprint photoresist is made by mixing acrylic resin, initiator, crosslinking agent, additives, etc. The nanoimprint process is susceptible to defects in the imprint template, which limits its application in integrated circuit processes.

• Directed Self Assembly (DSA) photoresist is a next-generation photoresist material that utilizes the different properties of different segments of block copolymers to spontaneously arrange and achieve pattern transfer. In directional self-assembly technology, block copolymers formed by the polymerization of two or more monomers with different chemical properties are used as raw materials. Under certain conditions, microphase separation occurs to form nanoscale patterns, inducing the patterns to become regularly arranged nanowire or nanopore arrays. Based on the difference in etching rates of different segments, the purpose is similar to photolithography. The size of microphase separation is related to the molecular weight of the block copolymer. The smaller the molecular weight, the smaller the size of the periodic structure formed. Therefore, directional self-assembled photoresist can break away from traditional lithography technology and achieve control over the lithography pattern and size through material design and control. Directional self-assembled photoresist has the advantages of low cost and high resolution. Its application fields include chip manufacturing, hard disk magnetic head manufacturing, photonic products, and other fields, which have been a hot research topic in recent years.

• Polyimide photoresist: Polyimide photoresist, also known as photosensitive polyimide resin (PSPI), is an organic polymer material generated by the condensation reaction and imidization reaction of organic dianhydride monomers and organic diamine monomers in organic solvents. It has both the photolithography characteristics of ordinary photoresist and unique properties such as thermal stability, electrical insulation, low dielectric constant, and dielectric loss. In the manufacturing and packaging process of integrated circuits, it is applied to surface passivation layers and stress buffering absorption layers, interlayer insulation films for multi-layer interconnect circuits, as well as liquid crystal alignment layer films for liquid crystal displays (LCDs) and insulation layers for organic light-emitting devices (OLEDs). The production of a passivation layer on the surface of a chip is achieved by coating polyimide resin or its precursor onto the surface of the device and curing it through high-temperature baking. The polyimide resin used for chip passivation layer includes standard polyimide resin and photosensitive polyimide resin. Standard polyimide resin can be used to create three-dimensional patterns or through holes through photolithography process with the help of photoresist. The process steps are complex and the device yield is relatively low; The photosensitive polyimide resin can be directly exposed/developed to complete the required pattern or opening production. After photolithography, it undergoes high-temperature condensation to complete the ring closing process, with relatively few process steps and relatively high device yield. The interlayer insulation film of multi-layer interconnect circuits is formed by coating a polyimide photosensitive resin (PSPI) solution on the substrate surface. After UV (I or G line) exposure, the solubility difference between the photomask blocking resin and the non blocking resin increases, and then using a developing solution to remove the easily soluble resin to obtain a three-dimensional photolithography pattern. The polyimide resin forming the photolithography pattern undergoes high-temperature curing to complete the imidization reaction and form a polyimide cured layer.