Crosses questions Microscale part

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Domande socrative microscale: DOMANDE SOCRATIVE 1. Photolithography is: a. The most widely used microfabrication technique in IC industry b. A particular type of lithography, requiring light to transfer a pattern onto a surface. c. Allows to deposit a thin film of materials through the use of light d. Is based on the use of photoresist (special photosensitive formulation of silicon) 2. In a cleanroom: a. The pressure is slightly below the atmospheric one to avoid the contamination of the external world. b. The environment is characterized by low level of environmental pollutants c. The air control occurs through HEPA or ULPA filters, which keep the environment sterile d. The standard level is defined by the count of particles of specific size e. The light is always yellow/orange to minimize the presence of UV components f. Airlocks are rooms interpose between the clean environment and the external world, where users are allowed to wear special suits, goggles, gloves. 3. Wafer cleaning is performed at the beginning of the process to remove dirt and oxidation, thus enhancing the adhesion of photoresists: 4. A photoresist: a. Is a resin characterized by its ability to crosslink when exposed to light b. Is composed by 3 components: polymer, sensitizer and solvent c. Can be either positive and negative d. If positive requires a negative mask to be properly transferred though photolithography 5. Spincoating a. is a process used to deposit a photoresist on a wafer controlling the spreading diameter (i.e. the covered area) b. is a process used to deposit a photoresist on a wafer controlling the thickness of the coating c. consists in the dispensing the photoresist on a wafer, enabling its spreading and accelerating to the desired rotation speed for a fixed amount of time d. of…