Patent ID: 6753540
Filing Date: 2004-06-22
Classification: B82Y,H01J

Abstract:
A lithographic method using a variable-area electron-beam lithography machine having first and second baffle plates, each of said first and second baffle plates having an aperture, said lithographic method comprising the steps of:passing an electron beam through said first baffle plate having the aperture with four right-angled corners; directing the electron beam emerging from the aperture in said first baffle plate at said second baffle plate; and directing the electron beam emerging from the aperture in said second baffle plate at a material to be written, wherein said electron-beam lithography machine is capable of shaping a cross section of the electron beam emerging from the aperture in the second baffle plate into a rectangle with four right-angled corners and right-angled isosceles triangles, wherein when a trapezoidal graphical figure having a top base, a bottom base, and two legs is to be written on said material, a sequence of operations is performed, and wherein said sequence of operations consists of performing a first step consisting of making a decision as to whether the angle made between one of the legs and the normal to the bottom base is 45 degrees and whether the angle made between the other leg and the normal to the bottom base is 45 or 0 degrees, performing a second step consisting of making a decision as to whether it is necessary to divide the trapezoidal graphical figure in the height direction if the result of the decision made in the first step is YES, performing a third step consisting of dividing the trapezoidal graphical figure in the height direction using a unit division length equal to the length of the bottom base of the trapezoidal graphical figure, separating portions including legs from resulting figure parts, and writing the separated portions including the legs by the right-angled isosceles triangles of the cross section of the beam if the result of the decision made in the second step is YES, performing a fourth step consisting of separating the portions including the legs of the trapezoidal graphical figure and writing the separated portions including the legs by the right-angled isosceles triangles of the cross section of the beam if the result of the decision made in the second step is NO, performing a fifth step consisting of making a decision as to whether it is necessary to separate the portions including the legs if the result of the decision made in the first step is NO, and performing a sixth step consisting of separating the portions including the legs if the result of the decision made in the fifth step is YES, and writing the portions including the legs by the right-angled isosceles triangles of the cross section of the beam if the angle made between the leg of each separated portion and the bottom base is 45 degrees.