Rectangle/lattice data conversion method for charged particle beam exposure mask pattern and charged particle beam exposure method

A charged particle beam exposure method with performing proximity effect correction by adjusting widths of a plurality of patterns of a mask for collectively exposing by a charged particle projection method, said method comprising the steps of:

• (a) selecting a representative pattern from said plurality of patterns to determine a reference exposure intensity Eth on the basis of said representative pattern;
• (b) determining a backscattering intensity distribution Fb of said plurality of patterns;
• and
• (c) adjusting a pattern width W of each pattern such that a width of a forward scattering intensity distribution at a slice level (Eth−Fb) becomes equal to a design width W0i.

A rectangle-to-lattice data conversion method for a charged particle beam exposure mask pattern that, when a rectangular pattern or a rectangle of part thereof is actually or imaginarily formed as a first rectangular pattern on a sensitive substrate by charged particle beam exposure, converts a second rectangular pattern on a mask corresponding to said first rectangular pattern to a lattice pattern including plural pattern subshapes in order to reduce an exposure dose, wherein if a width of a pattern subshape is W, a space width between pattern subshapes is S, an area density of a lattice pattern is αp, the minimum value of a forward scattering intensity in the first rectangular pattern is Ffmin×αp and a position assuming the minimum value is P, the method comprises the steps of:

• (a) obtaining a function D(W,S) representing said area density αp on the basis of a geometric relation of said lattice pattern, and obtaining a function E(P:
• W, S) representing a forward scattering intensity at said position P by surface-integration of a forward scattering term of an energy intensity distribution function;
• and
• (b) obtaining said pattern subshape width W and said space width S satisfying relations D(W, S)=αp and E(P:
• W, S)=Ffmin×αp, given both of an area density αp and a forward scattering intensity reduction ratio Ffmin.

A rectangle-to-lattice data conversion method that, when a rectangular pattern or a rectangle of part thereof is actually or imaginarily formed as a first rectangular pattern on a sensitive substrate by charged particle beam exposure, converts a second rectangular pattern on a mask corresponding to said first rectangular patter to a lattice pattern including plural pattern subshapes in order to reduce an exposure dose, wherein if a width of a pattern subshape is W, a space width between pattern subshapes is S, an area density of said lattice pattern is αp, the minimum value of a forward scattering intensity in said first rectangular pattern is Ffmin×αp and a position assuming the minimum value is P, the method comprises the steps of:

• (a) obtaining a function D(W, S) representing said area density αp on the basis of a geometric relation of said lattice pattern, and obtaining a function E(P:
• W, S) representing a forward scattering intensity at said position P by surface-integration of a forward scattering term of an energy intensity distribution function;
• (b) determining values of said pattern subshape width W and said space width S on the basis of said function D(W, S)=αp, and values of said pattern subshape width W and said space width S or a value of a relation formula of S and W, given all of an area density αp, an allowable lower limit Ffmin of a forward scattering intensity reduction ratio Ffmin, a common allowable lower limit value Lmin of both said pattern subshape width W and said space width S, and the values of said pattern subshape width W and said space width S or the value of the relation formula of S and W;
• and
• (c) adopting the values of said pattern subshape width W and said space width S as parameters to determine said lattice pattern in a case where a condition is satisfied that W≧Lmin, S≧Lmin and E(P:
• W, S)=Ffmin×αp.

A rectangle-to-lattice data conversion method for a charged particle beam exposure mask pattern that, when a rectangular pattern or a rectangle of part thereof is actually or imaginarily formed as a first rectangular pattern on a sensitive substrate by charged particle beam exposure, converts a second rectangular pattern on a mask corresponding to said first rectangular pattern to a first lattice pattern in order to reduce an exposure dose, comprising the steps of:

• (a) dividing said second rectangular pattern into plural rectangular regions;
• (b) grouping said plural rectangular regions such that adjacent rectangular regions are included into first and second complementary patterns, respectively, complementary to each other in order to form said first lattice pattern using two masks complementary to each other;
• (c) converting each of said plural rectangular regions to a second lattice pattern;
• and
• (d) performing a boundary processing on each of said second lattice patterns such that at least one side of each peripheral subshape thereof is in contact with a side of a rectangular region corresponding to each of the second lattice patterns.