JP3277746B2 - Electron beam drawing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam drawing apparatus .

[0002]

2. Description of the Related Art In a conventional electron beam lithography apparatus, as shown in FIG. 2, there is a limit in a deflection area 204 for projecting an electron beam onto a sample surface to perform writing. Is repeated by moving the sample stage to the next deflection area and performing writing.If a mask is set on the sample stage, it is assumed that the mask is always horizontal to the ideal horizontal plane for writing. The sample stage was moved at a constant moving pitch amount 205.

However, in practice, the mask on the sample stage is mounted on a cassette 202 used for movement from the outside of the apparatus to set the sample stage on the sample stage with four-point support using springs. The cassette is pushed up to a predetermined position by the four points supported by the spring, and the inclination of the mask due to the variation between these four points of the spring pressure and the variation of the height of the cassette reference plane at the four points cause the mask to be drawn with respect to the ideal horizontal plane. Tilt occurs.

As shown in FIG. 3, when the mask is set horizontally with respect to the ideal drawing horizontal plane, the movement pitch amount 304 of the mask itself is the same as the movement pitch amount 303 of the sample stage. In the case where the mask is set to be inclined with respect to the ideal drawing horizontal plane, the movement pitch amount 305 of the mask itself becomes larger than the movement amount of the sample stage. For this reason, when the sample stage is moved from the first electron beam deflection region to the next electron beam deflection region, when the mask is tilted and set on the sample stage, the movement pitch amount 305 of the mask itself and the sample stage The difference in the moving pitch amount 303 exists as an error factor of the writing position.

[0005]

An object of the present invention is to perform drawing with high accuracy by correcting a drawing position error caused by the inclination of a mask generated when the mask is loaded.

[0006]

In order to solve the above problems, the height of the mask surface set on the sample stage is measured by a detector before writing, and the X and Y directions of the mask are determined from the difference in height. The electron beam lithography system in which the sample stage is moved by calculating the amount of inclination of each and correcting the moving pitch amounts in the X and Y directions.

[0007]

Before the writing, the height of the mask surface set on the sample stage is measured by a detector, and the amount of tilt in the X and Y directions of the mask is calculated from the difference in height, thereby obtaining an error caused by the tilt. Since the sample stage is moved and drawn by correcting the moving pitch amounts in the X and Y directions, a highly accurate circuit pattern can be created.

[0008]

FIG. 1 shows an embodiment of the present invention. Here, the mask is inclined with respect to the ideal drawing horizontal plane only in the X direction. First, a mask is mounted on a cassette and set on a sample stage of an electron beam lithography apparatus, and four corners 101A, 101B, 101C, 10C of the mask are detected by a detector as shown in FIG.
The height of 1D is measured, and between 101A-101D in the Y direction, 1
The height average between 01B and 101C is calculated by the following formula (101A-101D).

[0009]

(1A + 101D) / 2 (1) (101B-101C)

[0010]

(101B + 101C) / 2 (Equation 2) Next, as shown in FIG. 1, 102A is the distance in the X direction between the points at which the heights are measured, and is the distance between 101A and 101B or between 101C and 101D. Becomes 102B is the difference in height in the X direction, (Equation 1) and (Equation 2).

[0011]

102B = {(101A + 101D) / 2} − {(101B + 101C) / 2} (Equation 3) 102C is the amount of movement of the sample stage required to move 102A, which is the distance between measurement points on the mask,

[0012]

(Equation 4)

## EQU1 ##

In FIG. 1, reference numeral 103C denotes a moving pitch amount of the sample stage, and 103A denotes a moving pitch amount of the mask inclined with respect to the ideal drawing horizontal plane.
It is necessary to correct the moving pitch amount 103C of the sample stage so that 3A becomes the same as the electron beam deflection area. So 103C is proportional to 102A and 103A, and 102C and 103C,

[0015]

103C = 102C × 103A / 102A (Equation 5) This is the moving pitch in the X direction of the sample stage to be corrected in order to move the inclined mask by the deflection area.

The movement pitch of the sample stage in the Y direction can be calculated in the same manner. Therefore, (Equation 5)
By correcting the amount of movement of the sample stage from the amount of tilt of the mask, and by moving the sample stage in the X and Y directions, a circuit pattern can be drawn at a desired position and a highly accurate mask can be created. Will be possible.

In addition, as an application example of the present invention, a method in which the stage movement pitch is fixed based on the amount of tilt of the mask, and the center position of the electron beam deflection area is corrected for drawing is performed. There is a method in which the tilt amount is measured by dividing the sample stage and the moving pitch amount of the sample stage is corrected for each block.

[0018]

According to the present invention, highly accurate drawing of a circuit pattern on a mask can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a sample stage movement pitch correction based on the present invention.

FIG. 2 is an explanatory diagram of a sample stage moving method.

FIG. 3 is an explanatory diagram of a moving pitch amount in a horizontal / tilted state of a mask.

[Explanation of symbols]

101A to 101D: height measurement points, 102A: distance between height measurement points, 102B: height between measurement points due to the inclination of the mask, 102C: movement amount of the sample stage necessary for moving 102A, 103A: inclination state Mask moving pitch amount, 103C ... Sample stage moving pitch amount.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-309627 (JP, A) JP-A-7-37777 (JP, A) JP-A-5-299330 (JP, A) JP-A-61- 34935 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/027

Claims (1)

(57) [Claims] 1. An electron gun for generating an electron beam, an electron optical system for projecting an electron beam emitted from the electron gun onto a sample surface, and a deflection control system for scanning the electron beam on the sample surface. A detector for measuring the height of a mask fixed to the sample surface; and the electron optical system, the deflection control system,
In an electron beam lithography apparatus comprising the signal processing system and a stage control system for moving the sample, the height of a mask surface set on a sample stage is measured by the detector to determine the X and Y directions of the mask. An electron beam lithography apparatus for calculating a tilt amount in a direction and correcting a drawing position error caused by the tilt to perform drawing.