A semiconductor substrate carrier is a device capable of holding a plurality of semiconductor substrates. The semiconductor substrate carrier is typically one of two types: a semiconductor boat (boat) or a semiconductor cassette (cassette). The boat is typically used in high temperature applications, wherein the temperature is greater than about 200 degrees Celsius. The cassette is typically used in applications below about 200 degrees Celcius. Many cassettes comprise a plastic material, such as polypropylene or a perfluoroalkoxy fluorocarbon (Teflon.RTM. PFA), for example.
Currently, three methods of transporting a cassette are commonly used. The cassette may be transported by hand, using a ring handle, or using an elevator that is typically part of a mechanical cassette transporting system. When a person transports the cassette by holding the cassette in his or her hand, particles or sodium from the person's hand may transferred to the substrates. Particles typically increase defect density and lower the substrate yield, and sodium typically makes a metal-insulator-semiconductor device unreliable. A cassette may have flanges adjacent the top of the cassette. A ring handle 10 as shown in FIG. 1 includes the ring 11 and hooks 12 that may be slid along the flanges and over any substrates that are within the cassette. Liquids or particles on the handle may be transferred to the substrates when the handle is in contact with the cassette or when the handle is being placed on or removed from the cassette. In addition, the cassette typically must be touched by a person's hand while the ring handle is being placed on or removed from the cassette and may cause particle or sodium contamination. The ring handle 10 cannot be used to load many types of equipment including many dryers that are used to remove liquids from the surface of the substrate. Individual pieces of equipment may have a mechanical cassette transporting system including an elevator that includes fork members, but the fork members are typically not interchangeable between different types of elevators throughout the substrate fabrication area.
USPTO Backgrounds
USPTO Backgrounds