Patent Number: 
Section: claims

1. A charged-particle beam writing method for deflecting a charged-particle beam and writing each pattern onto a sample placed on a stage, comprising the steps of:calculating a charge amount distribution in an irradiation region of the charged-particle beam and a charge amount distribution in a non-irradiation region thereof, using an exposure distribution of the charged-particle beam applied onto the sample, and a fogging electron amount distribution;calculating a distribution of a position displacement amount of the charged-particle beam on the sample, based on the charge amount distributions in the irradiation and non-irradiation regions; anddeflecting the charged-particle beam, based on the distribution of the position displacement amount and writing each pattern onto the sample. 2. The charged-particle beam writing method according to claim 1, further including a step for calculating the fogging electron amount distribution, based on the exposure distribution and a spread distribution of fog electrons expanded from the irradiation region of the sample irradiated with the charged-particle beam to the non-irradiation region. 3. The charged-particle beam writing method according to claim 2, the fogging electron amount distribution is calculated by convolution the exposure distribution and integral of the spread distribution function. 4. The charged-particle beam writing method according to claim 1, further including a step for calculating a dose distribution, based on a pattern density distribution set for every predetermined region of the sample, anda step for calculating the exposure distribution, based on the pattern density distribution and the dose distribution. 5. The charged-particle beam writing method according to claim 4, the dose distribution is calculated using a proximity effect correction equation of backscattered electrons. 6. The charged-particle beam writing method according to claim 1, wherein the charge amount distribution in the non-irradiation region is calculated using a function CF(F) expressed in the following equation (a):CF(F)=−c1×Fα  (a)(where F: fogging electron amount distribution, c1: constant, and 0<α<1), and wherein the charge amount distribution in the irradiation region is calculated using a function CE(E,F) expressed in the following equation (b):CE(E,F)=CE(E)+CFe(F)=c0−c1×Fα  (b)(where E: exposure distribution, F: fogging electron amount distribution, c0 and c1: constants, and 0<α<1). 7. The charged-particle beam writing method according to claim 6, wherein 0.3≦α≦0.4 in the equations (a) and (b). 8. The charged-particle beam writing method according to claim 1, wherein the charge amount distribution in the non-irradiation region is calculated using a function CF(F) expressed in the following equation (a):CF(F)=−c1×Fα  (a)(where F: fogging electron amount distribution, c1: constant, and 0<α<1). 9. The charged-particle beam writing method according to claim 8, wherein 0.3≦−α≦0.4 in the equation (a). 10. The charged-particle beam writing method according to claim 1, wherein the charge amount distribution in the irradiation region is calculated using a function CE(E,F) expressed in the following equation (b):CE(E,F)=CE(E)+CFe(F)=c0−c1×Fα  (b)(where E: exposure distribution, F: fogging electron amount distribution, c0 and c1: constants, and 0≦α≦1). 11. The charged-particle beam writing method according to claim 10, wherein 0.3≦α≦0.4 in the equation (b). 12. The charged-particle beam writing method according to claim 1, wherein the charge amount distribution in the irradiation region is calculated using a polynomial function of pattern density distribution, the dose distribution, the exposure distribution and the fogging electron amount distribution, and wherein the charge amount distribution in the non-irradiation region is calculated using a polynomial function of the fogging electron amount distribution. 13. The charged-particle beam writing method according to claim 1, wherein the charge amount distribution in the irradiation region is calculated using a polynomial function expressed in the following equation (c):C(E,F)=(d0+d1×ρ+d2×D+d3×E)+(e1×F+e2×F2+e3×F3)  (c)(where ρ: pattern density distribution, D: dose distribution, E: exposure distribution, F: fogging electron amount distribution, and d0, d1, d2, d3, e1, e2 and e3: constants). 14. The charged-particle beam writing method according to claim 1, wherein the charge amount distribution in the non-irradiation region is calculated using a polynomial function expressed in the following equation (d):CF(F)=f1×F+f2×F2+f3×F3  (d)(where F: fogging electron amount distribution, and f1, f2 and f3: constants). 15. The charged-particle beam writing method according to claim 1, wherein the charge amount distribution in the irradiation region is calculated using a polynomial function expressed in the following equation (c):C(E,F)=(d0+d1×ρ+d2×D+d3×E)+(e1×F+e2×F2+e3×F3)  (c)(where ρ: pattern density distribution, D: dose distribution, E: exposure distribution, F: fogging electron amount distribution, and d0, d1, d2, d3, e1, e2 and e3: constants), andwherein the charge amount distribution in the non-irradiation region is calculated using a polynomial function expressed in the following equation (d):CF(F)=f1×F+f2×F2+f3×F3  (d)(where F: fogging electron amount distribution, and f1, f2 and f3: constants). 16. A charged-particle beam writing apparatus for deflecting a charged-particle beam by a deflector and writing each pattern onto a sample placed on a stage, comprising:position displacement amount distribution calculating means for calculating a distribution of a position displacement amount of the charged-particle beam lying on the sample, based on a charge amount distribution in an irradiation region of the sample irradiated with the charged-particle beam, and a charge amount distribution in a non-irradiation region unirradiated therewith; anddeflector control means for controlling the deflector based on the distribution of the position displacement amount. 17. The charged-particle beam writing apparatus according to claim 16, further including charge amount distribution calculating means for calculating the charge amount distributions in the irradiation and non-irradiation regions using an exposure distribution of the charged-particle beam applied onto the sample and a fogging electron amount distribution. 18. The charged-particle beam writing apparatus according to claim 17, further including fogging electron amount distribution calculating means for calculating the fogging electron amount distribution, based on the exposure distribution and a spread distribution of fog electrons expanded from the irradiation region irradiated to the non-irradiation region. 19. The charged-particle beam writing apparatus according to claim 18, further including exposure distribution calculating means for calculating the exposure distribution, based on a pattern density distribution and a dose distribution set for every predetermined region of the sample. 20. The charged-particle beam writing apparatus according to claim 19, further including dose distribution calculating means for calculating the dose distribution, based on the pattern density distribution.