| 摘要 |
In electron beam testing systems wherein high energy, high resolution electron beams are used to test lithographic masks, a technique and apparatus are described for discharging electrons which are left on the surface of the mask, and which alter the input trajectory of the electron beam. The materials used in these masks are such that induced photoconductivity and photoemissivity are extremely low and are incapable of providing sufficient electron discharge. A thin, low work function coating is applied over the entire mask surface, the coating being transparent to the radiation which will later be incident upon the mask when it is used in a fabrication process. Due to induced photoemission in the thin coating layer, enough photoemitted electrons will be produced to balance the buildup of electrons from the electron beam, thereby discharging the surface of the mask. The electron beam is a high energy beam, having energies greater than about 5000 eV, and a resolution less than about 1 micrometer.
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