Method for exposing a pattern on an object by a charged particle beam

A method for exposing a device pattern on an object by selectively deflecting a beam of charged particles through apertures of a beam shaping mask, based upon design data that represents said device pattern to be exposed, said device pattern comprising a plurality of elemental patterns, said method comprising the steps of:

• defining a minimum size threshold of said plurality of elemental patterns corresponding to and defined by said design data;
• extracting, from the design data, fine exposure data comprising exposure data corresponding to and defining fine elemental patterns having a size smaller than said minimum size threshold;
• extracting, from the design data, mask data indicative of a plurality of apertures including an elongated aperture having a width smaller than said minimum size threshold;
• fabricating the beam shaping mask with the elongated aperture having the width smaller than said minimum size threshold, based on the mask data;
• and
• directing said beam at two intersecting edges of said elongated aperture formed in said beam shaping mask in accordance with the fine exposure data such that said beam passes through said elongated aperture, said beam being shaped by two opposing edges that form said elongated aperture in order for said beam to have an elongated cross section extending along said elongated aperture with a variable length.

A method of fabricating a mask used in exposing a device pattern on an object by passing a beam of charged particles through the mask based upon design data, the design data defining the device pattern in accordance with a plurality of elemental patterns and comprising plural elemental pattern design data defining respective, plural elemental patterns of different respective configurations and sizes and mask data defining the location and size in the device pattern of each of the elemental patterns and the number of times each elemental pattern is used in the design pattern, the method comprising:

• defining a first threshold relative to the number of times each elemental pattern is used in the device pattern, each elemental pattern which exceeds the first threshold being designated as a block elemental pattern and each elemental pattern which does not exceed the first threshold being designated as a variable elemental pattern;
• defining a second threshold relative to the range of respective sizes of each elemental pattern;
• extracting, from the design data, block elemental pattern design data defining the block elemental patterns;
• extracting, from the design data, variable elemental pattern design data defining the variable elemental patterns which exceed the second threshold;
• extracting, from the design data, the variable elemental pattern design data defining the variable elemental patterns which do not exceed the second threshold;
• extracting, from the design data, the mask data defining the location in the device pattern of each of the elemental patterns in the device pattern and the number of times each elemental pattern is used;
• and
• fabricating a mask in accordance with:
• forming an individual block elemental pattern aperture respectively corresponding to each block elemental pattern defined by said extracted block elemental pattern design data at a location on the mask designated by the mask data,
• forming an aperture in the mask having first and second transverse dimensions each of which exceeds the corresponding first and second transverse dimensions of the variable elemental patterns which exceed the second threshold, and
• for each variable elemental pattern which does not exceed the second threshold, forming a corresponding aperture in which the smaller of the first and second dimensions is the same as the smaller dimension of the variable elemental pattern which does not exceed the second threshold.

A method of forming a mask to be used for exposing, on an object, a device pattern comprising a plurality of different elemental patterns by selectively deflecting a beam of charged particles through a plurality of exposure apertures in the mask, the exposure apertures being of respective, different sizes and shapes corresponding to the plurality of different elemental patterns and being formed at respective, different locations in the mask, the beam being selectively deflected in accordance with design data representing the device pattern and the plurality of elemental patterns thereof and the design data further comprising mask data defining the plurality of apertures, the respective, different sizes and shapes thereof and the different locations thereof in the mask, said method comprising the steps of:

• extracting, from said design data, block exposure data corresponding to and defining a set of selected elemental patterns of said plurality of elemental patterns, each selected elemental pattern corresponding to a block exposure aperture to be formed in the mask and through which the selectively deflected beam passes and is shaped, thereby to expose the corresponding elemental pattern on the object in accordance with the device pattern;
• extracting, from said design data, variable exposure data corresponding to and defining the remaining elemental patterns, other than said set of selected elemental patterns, to be exposed on the object in accordance with the device pattern;
• defining a minimum size threshold of the remaining elemental patterns;
• separating said variable exposure data into fine exposure data corresponding to and defining fine elemental patterns having a size smaller than said minimum size threshold and coarse exposure data corresponding to and defining coarse elemental patterns having a size larger than said minimum size threshold, the fine elemental patterns corresponding to fine exposure apertures and the coarse elemental patterns corresponding to coarse exposure apertures to be formed in the mask and through which the selectively deflected beam passes thereby to expose the corresponding elemental pattern on the object in accordance with the device pattern, each coarse exposure aperture having two intersecting edges and the beam being selectively deflected for passing therethrough and for adjusting the extent of overlapping of the beam and the coarse exposure aperture, relatively to the respective two intersecting edges thereof, for shaping of the beam;
• extracting, from said design data, mask data indicative of the locations, the sizes and the shapes, respectively, of the block exposure apertures, the coarse exposure apertures and the fine exposure apertures to be formed in said beam shaping mask, respectively corresponding to, and to be used for shaping said beam of charged particles thereby to expose, the selected elemental patterns, the coarse elemental patterns and the fine elemental patterns;
• and
• fabricating the beam shaping mask, including forming at the respective locations therein, said block exposure apertures, said coarse exposure apertures and said fine exposure apertures of the respective sizes and shapes thereof, based upon said extracted mask data.

A method for exposing, on an object, a device pattern comprising a plurality of different elemental patterns by selectively deflecting a beam of charged particles through a plurality of exposure apertures in a mask, the exposure apertures being of respective, different sizes and shapes corresponding to the plurality of different elemental patterns and being formed at respective, different locations in the mask, the beam being selectively deflected in accordance with design data representing the device pattern and the plurality of elemental patterns thereof and the design data further comprising mask data defining the plurality of apertures, the respective, different sizes and shapes thereof and the different locations thereof in the mask, said method comprising the steps of:

• processing the design data in accordance with the steps of:
• extracting, from said design data, block exposure data corresponding to and defining a set of selected elemental patterns of said plurality of elemental patterns, each selected elemental pattern corresponding to a block exposure aperture to be formed in the mask and through which the selectively deflected beam passes and is shaped, thereby to expose the corresponding elemental pattern on the object in accordance with the device pattern,
• extracting, from said design data, variable exposure data corresponding to and defining the remaining elemental patterns, other than said set of selected elemental patterns, to be exposed on the object in accordance with the device pattern.
• defining a minimum size threshold of the remaining elemental patterns,
• separating said variable exposure data into fine exposure data corresponding to and defining fine elemental patterns having a size smaller than said minimum size threshold and coarse exposure data corresponding to and defining coarse elemental patterns having a size larger than said minimum size threshold, the fine elemental patterns corresponding to fine exposure apertures and the coarse elemental patterns corresponding to coarse exposure apertures to be formed in the mask and through which the selectively deflected beam passes thereby to expose the corresponding elemental pattern on the object in accordance with the device pattern, each coarse exposure aperture having two intersecting edges and the beam being selectively deflected for passing therethrough and for adjusting the extent of overlapping of the beam and the coarse exposure aperture, relatively to the respective two intersecting edges thereof, for shaping of the beam, and
• extracting, from said design data, mask data indicative of the locations, the sizes and the shapes, respectively, of the block exposure apertures, the coarse exposure apertures and the fine exposure apertures to be formed in said beam shaping mask, respectively corresponding to, and to be used for shaping said beam of charged particles thereby to expose, the selected elemental patterns, the coarse elemental patterns and the fine elemental patterns;
• and
• fabricating the beam shaping mask, including forming at the respective locations therein, said block exposure apertures, said coarse exposure apertures and said fine exposure apertures of the respective sizes and shapes thereof, based upon said extracted mask data;
• and
• exposing said device pattern on the object by selectively passing said beam through said block exposure apertures, said coarse exposure apertures and said fine exposure apertures, based upon said corresponding and extracted block exposure data, coarse exposure data and fine exposure data, respectively, and said corresponding and extracted mask data indicating the respective locations thereof.