Topography simulation apparatus, topography simulation method, and topography simulation program

1. A topography simulation apparatus comprising a processor and a memory connected to the processor, the memory storing instructions executable by the processor to:

set a function indicating a position relationship between a point in a calculation region and a material surface in the calculation region;

determine whether or not a particle moving in the calculation region collides with the material surface, wherein the particle simulates a molecule or an ion; and

update a value of the function, responsive to determining that the particle collides with the material surface.

2. The apparatus according to claim 1 ,

wherein the memory further stores instructions executable by the processor to determine whether or not a topography of the material surface changes due to the particle, responsive to determining that the particle collides with the material surface,

wherein the instructions to update the value of the function include instructions executable by the processor to update the value of the function, responsive to determining that the particle collides with the material surface and the topography of the material surface changes due to the particle.

3. The apparatus according to claim 1 ,

wherein the instructions to determine whether or not the particle moving in the calculation region collides with the material surface include instructions executable by the processor to calculate a trajectory of the particle by a direct simulation Monte Carlo (DSMC) method.

4. The apparatus according to claim 1 ,

wherein the instructions to update the value of the function include instructions executable by the processor to update the value of the function such that a surface moving distance of the material each time the particle collides is constant.

5. The apparatus according to claim 1 ,

wherein the calculation region includes a plurality of cells obtained by dividing the calculation region, and a plurality of lattice points constituting each cell.

6. The apparatus according to claim 5 ,

wherein the instructions to determine whether or not the particle moving in the calculation region collides with the material surface include instructions executable by the processor to specify a cell which is located in a collision position of the particle, and

wherein the instructions to update the value of the function include instructions executable by the processor to update the value of the function at lattice points constituting the cell which is located in the collision position of the particle.

7. The apparatus according to claim 6 ,

wherein the instructions to determine whether or not the particle moving in the calculation region collides with the material surface include instructions executable by the processor to specify the cell which is located in the collision position of the particle, based on values of the function at lattice points constituting a cell which is located in the material surface.

8. The apparatus according to claim 5 ,

wherein each cell has characteristic information indicating characteristics of a material in the cell, and

wherein the instructions to update the value of the function include instructions executable by the processor to update the value of the function, based on the characteristic information.

9. A non-transitory computer-readable storage medium storing instructions as a topography simulation program executable by a processor to:

set a function indicating a position relationship between a point in a calculation region and a material surface in the calculation region;

determine whether or not a particle moving in the calculation region collides with the material surface wherein the particle simulates a molecule or an ion; and

update a value of the function, responsive to determining that the particle collides with the material surface.

10. The non-transitory computer-readable storage medium according to claim 9 ,

wherein the medium further stores instructions executable by the processor to determine whether or not a topography of the material surface changes due to the particle, responsive to determining that the particle collides with the material surface,

wherein the instructions to update the value of the function include instructions executable by the processor to update the value of the function, responsive to determining that the particle collides with the material surface and the topography of the material surface changes due to the particle.

11. The non-transitory computer-readable storage medium according to claim 9 ,

wherein the instructions to determine whether or not the particle moving in the calculation region collides with the material surface include instructions executable by the processor to calculate a trajectory of the particle by a direct simulation Monte Carlo (DSMC) method.

12. The non-transitory computer-readable storage medium according to claim 9 ,

wherein the instructions to update the value of the function include instructions executable by the processor to update the value of the function such that a surface moving distance of the material each time the particle collides is constant.

13. The non-transitory computer-readable storage medium according to claim 9 ,

wherein the calculation region includes a plurality of cells obtained by dividing the calculation region, and a plurality of lattice points constituting each cell.

14. The non-transitory computer-readable storage medium according to claim 13 ,

wherein the instructions to determine whether or not the particle moving in the calculation region collides with the material surface include instructions executable by the processor to specify a cell which is located in a collision position of the particle, and

wherein the instructions to update the value of the function include instructions executable by the processor to update the value of the function at lattice points constituting the cell which is located in the collision position of the particle.

15. A topography simulation method comprising:

setting a function indicating a position relationship between a point in a calculation region and a material surface in the calculation region;

determining that a particle moving in the calculation region collides with the material surface, wherein the particle simulates a molecule or an ion;

updating a value of the function, responsive to determining that the particle collides with the material surface; and

outputting a changed topography of the material surface based on the updated value of the function.

16. The method according to claim 15 , wherein the calculation region includes a plurality of cells obtained by dividing the calculation region, and a plurality of lattice points constituting each cell.

17. The method according to claim 16 ,

wherein the determining that the particle moving in the calculation region collides with the material surface includes specifying a cell which is located in a collision position of the particle, and

wherein the updating the value of the function includes updating the value of the function at lattice points constituting the cell which is located in the collision position of the particle.

18. The method according to claim 16 ,

wherein each cell has characteristic information indicating characteristics of a material in the cell, and

wherein the updating the value of the function includes updating the value of the function, based on the characteristic information.