Apparatus for inspecting mask

#The present invention relates to a technical method that an electronic beam transmitting through a mask is detected by means of a detector, in which a plurality of elements is aligned in a plurality of lines, as well as transferred synchronously with movement of the mask, so that it would be achieved to inspect a mask with high resolution at high speed. The invention also relates to a technical method that, in scanning in a straight line at right angles to a direction of the plural elements of a CCD sensor with an electronic beam illuminating the mask, an electronic beam is scanned in a straight line with the extremely high accuracy without zigzag scan when a stage with an easy structure is used.

#Conventionally, inspection of a mask (reticle mask) for exposing an LSI circuit pattern or such on a wafer is carried out by illuminating a mask entirely by light, measuring the strength of the light transmitting through the mask so as to obtain its image, and then, referring to a circuit diagram. In the inspection by means of light, resolution is limited by a wavelength of the light, and the current highest resolution is around 0.1 mm.

#On the other hand, a scan type of electronic microscope (referred to SEM, hereinafter) is used for scanning an electronic beam narrowed down and radiated on a circuit pattern of a wafer after exposure and development with a mask so that a second electron, which is generated in the above scan, is detected to be used for inspecting a detailed structure of the above circuit pattern. A thin film forming a pattern in a stencil mask, however, has a thickness of around 2 to 20 mm, and when it is assumed that a minimum size of an opening portion of the pattern be 0.4 mm, an aspect ratio would be 5 to 50, which is extremely large compared with that of a usual structure of a surface of a wafer. Thus, the second electron generated in the opening portion cannot be taken to the outside even when the usual SEM is used to radiate an electronic beam narrowed down for scanning, and it causes a problem that the inside of the above opening cannot be inspected practically.

#FIG. 1 is a structural diagram of a system according to the invention.

#FIG. 2 shows an example of a detector according to the invention.

#FIG. 3 illustrates a structural diagram of a system of an integral part according to the invention.

#Embodiments and operations according to the invention will be described one by one in detail with reference to FIGS. 1 to 5.

#FIG. 1 illustrates a structure of a system according to the invention.

#In FIG. 1, a mask 1 is provided for undergoing a transmission type of inspection.