Patent Number: 050200836
Section: summary

BACKGROUND OF THE INVENTION This Invention relates to manufacture of semiconductor chips using X-rays, and particularly to the fabrication of patterned membrane X-ray masks and their use. Forming patterned images on semiconductor chips with X-rays through X-ray masks offers a number of advantages. X-rays can form more precise images than visible or ultra-violet light because they do not suffer as much diffraction as the latter. X-ray images are thus more precise than other images and avoid the imperfections that can ruin a chip. As is known, a single imperfection can ruin a semiconductor chip, and the use of X-rays increases the statistical yields of perfect chips. X-rays also may make increased packing densities possible. Patterned X-ray membrane masks are used to form images with X-rays. In the past, such patterned X-ray membrane masks have been manufactured by depositing X-ray absorbing materials such as tantalum, gold, tungsten, etc. on the surfaces of silicon membranes. While such patterned membrane X-ray masks have proven successful for many applications, they exhibit a number of disadvantages, both in fabrication and use. OBJECTS AND SUMMARY OF THE INVENTION An object of the invention is to improve X-ray masks, their fabrication, and use. According to a feature of this invention, these objects are attained in whole or in part, by fabricating the masks so that the X-ray absorbing materials penetrate into the X-ray transparent silicon membrane. These and other features of the invention are pointed out in the claims. Other objects and advantages of the invention will become evident from the following detailed description when read in light of the accompanying drawings.