基恩士测量仪多少钱:帮忙翻译~

One of the procedures used in making monolithic integrated circuits which overcomes this problem is photolithography based on photoresists. However, in recent years electron beam lithography based on electron resists has been used as an alternative method for cases in which resolution is desired. The lithographic process involves coating of the substrate, e.g.silicon dioxide,with resist and its exposure to light through a mask( image boundaries). Images can be produced by solvent development followed by etching and stripping of the resist. Resists must be capable of forming uniform pinhole-free films on a substrate by a simple process such as spinning, dip-coating or spraying, be of a high degree of purity, i.e. contain only low levels of ions to achieve no electrical properties, be easily removed by solvent dissolution, be thermally stable up to 150 centigrade to withstand the burn-in temperatures used for hybrid circuits, cause no stress on fine-wire bonds and no deleterious effects on active devices and be compatible with the devices and wire bonds of high density circuits.
Usually polymers are the only materials which fulfill these requirements. The interaction of organic polymers with energetic electrons or ultraviolet light results in structurally changed molecules which may either be broken down to smaller fragments or link together to form larger molecules. Interaction that causes a break in the main polymer chain and results in irradiated material having a lower average molecular weight than un-irradiated material allows positive-working resists to be formulated. Clearly the successful removal of irradiation-degraded polymer without affecting the un-irradiated material in the development process will occur if the original polymer has the highest possible molecular weight and is irradiated by moderate doses of electrons or ultraviolet light. Moreover, a polymer with a low glass transition temperature can easily be deformed and the resolution of fine patterns developed in a film of such a polymer may be impaired. Thus good positive resists should have a glass transition temperature above the highest temperature to which the resist will be subjected after development of the irradiated pattern in it.