Patent Number: 047486465
Section: summary

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an X-ray exposure system, and more particularly, to an X-ray lithography system in which X-rays from a synchrotron radiation source are irradiated through a beryllium window onto the masked semiconductor wafer. 2. Description of the Related Art In a lithography system, a semiconductor wafer or chip coated with a resist is exposed to beam radiation. Recently, in such lithographic radiation, an X-ray beam taken from synchrotron radiation has been used, in which X-rays from a synchrotron radiation source are irradiated through a beryllium window onto a masked semiconductor wafer, as disclosed in J. Vac. Sci. Technol. B 1(4), Oct.-Dec. 1983, pages 1262-1266. The beryllium window is installed between a vacuum chamber for transmitting the X-ray beam and an atmospheric exposure chamber for accommodating wafers, and therefore, is subjected to a pressure, as will be mentioned hereinafter in detail. The beryllium window must, therefore, have sufficient mechanical strength to withstand a pressure, but on the other hand, if the thickness of the beryllium window could be reduced, the intensity of the X-ray beam transmitted therethrough would be increased, as also mentioned hereinafter in detail. Therefore, it would be advantageous if the thickness of the beryllium window were reduced. SUMMARY OF THE INVENTION An object of the present invention is to provide an X-ray lithography system using synchrotron radiation, capable of overcoming the drawbacks mentioned above with reference to the related art. Another object of the present invention is to provide an X-ray lithography system using synchrotron radiation, wherein the thickness of a beryllium window is reduced, but X-ray exposure on a large-sized wafer is ensured. According to the present invention, there is provided an X-ray lithography system comprising: an X-ray generation source including means for separating an X-ray beam from synchrotron radiation beams; a vacuum chamber for defining a passage of the X-ray beam; a scanning mirror arranged in one section of the vacuum chamber for reflecting the X-ray beam; means for oscillating the scanning mirror so as to vertically scan the reflected X-ray beam; a beryllium window defined as a part of the vacuum chamber, through which the X-ray beam is irradiated into an exposure chamber in which is arranged a work to be exposed to the X-ray radiation; and, means for vertically oscillating the beryllium window in such a manner that the beryllium window is shifted up and down in synchronization with the scanning operation of the X-ray beam at a position of the beryllium window. In a preferred embodiment of this invention, the beryllium window is relatively wide in the horizontal direction, but narrow in the vertical direction, for example, a size of 50 mm.times.5 mm, and the thickness thereof is relatively thin, for example, 10 .mu.m. According to the present invention, it is possible to increase the intensity of an X-ray beam transmitted through the beryllium window, since a beryllium window having a relatively thin thickness can be used and, therefore, any decrement or loss of the X-ray beam is relatively small, compared to a beryllium window in a conventionally known X-ray lithography system. Further, due to the scanning operation of the X-ray beam, a wide exposure area can be maintained.