A semiconductor is a substance whose conductivity is between that of an insulator and a conductor. It has specific electrical properties and can be used to make diodes, integrated circuits (ICs), and transistors. Semiconductors are sometimes also called ICs or microchips in a broad sense, while semiconductor manufacturing is the process of preparing ICs from semiconductor materials, in which photolithography is a key step. The photoresists used in the semiconductor industry are collectively referred as semiconductor photoresists. As a key material for photolithography, they are also indispensable in semiconductor manufacturing.
The most common classification method for semiconductor photoresists is according to the wavelength range of exposure. G-line resists (436 nm), I-line resists (365 nm), KrF resists (248 nm), and ArF resists (193 nm) are available in Alfa Chemistry. The first two are collectively referred to as G/I-line resists, which belong to ultraviolet photoresists, while KrF and ArF resists belong to deep UV photoresists. Among them, G/I-line resists are mainly used in the photolithography process of high-pressure mercury lamp light sources, while KrF and ArF resists are mainly used in the photolithography process of KrF and ArF laser light sources.
Applications in Semiconductor Fabrication
Semiconductor fabrication converts raw materials into functional electronic components through a series of complex and highly specialized steps. When it comes to semiconductor fabrication, semiconductor photoresists play a vital role, especially during the photolithography process. To better comprehend the role of photoresists, it is necessary to have a brief understanding of the semiconductor fabrication process. The fabrication process can be summarized in the following steps:
- Deposition: Thin films of conductive, insulating, or semiconducting materials are deposited on silicon wafers using physical vapor deposition (PVD), chemical vapor deposition (CVD), or atomic layer deposition (ALD).
- Photolithography: The steps of photolithography involves coating the photoresist on the wafer surface, drawing patterns on the mask, and aligning the mask with the photoresist. Under light at a specific wavelength, the photoresist undergoes a chemical reaction, resulting in patterns transferred to the photoresist.
- Etching: Etching refers to the selective removal of unnecessary parts using a liquid or gaseous etchant until the desired circuit pattern remains on the wafer surface.
- Ion impact: Dopants are implanted into specific regions of the semiconductor component in the form of ions. The current is controlled to adjust the conductive characteristics of some patterns so that the device can obtain precise electronic characteristics.
- Packaging and testing: Electronic packaging protects the final product from the surrounding environment, while product testing ensures its quality.
