JPH0194619A - Shot control circuit for electron beam lithography equipment - Google Patents

Abstract

PURPOSE:To improve printing throughput without deteriorating printing accuracy, by providing are electronic beam printing apparatus with a shot dividing circuit for dividing an ordinary single shot into several shots while adapting it such that the position of a stage is corrected in every shot. CONSTITUTION:A variable-shape electronic beam Bi' is unblanked so that a beam shot is given to a material 11 disposed on a stage 12 for a predetermined period of time, and such beam shots are performed in series to produce a pattern. An electron ic beam printing apparatus constructed in this manner is provided with a shot dividing circuit 18 for dividing one shot into several shots, and is adapted such that an ordinary one shot is divided by the circuit 18 into several shots while the position of the stage is corrected in every shot. According to ar embodiment, a deflection correcting circuit 20 receives graphical data of the divided shots and a deflection correcting value, and outputs graphical data in which the error of the position of the stage has been corrected. A DAC amplifier 21 converts the graphical data into an analogue signal and drives a positioning deflecting system 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a shot control circuit for an electron beam lithography system, and more specifically, a shot control circuit for an electron beam lithography system that suppresses blurring of figures as much as possible. Regarding.

(Prior Art) Electron beam lithography apparatuses have been attracting attention in the IC manufacturing field in recent years because they can directly expose a pattern to a lithography material placed on a material stage. Specifically, a resist is applied onto a material (wafer), and a beam based on drawing data is irradiated onto the material surface coated with this resist, thereby obtaining an exposure pattern based on the drawing data.

In this type of electron beam drawing apparatus, when drawing a pattern, the drawing position is determined by a deflector.

Normally, when writing with an electron beam on a material placed on a material stage, the current position of the material stage is usually different from the ideal position (planned position). Therefore, the position of the material stage (hereinafter simply referred to as stage) is measured with high precision using a laser length measuring device, and the error amount (hereinafter abbreviated as LBC value) from the determined ideal position is fed back to the deflector to determine the drawing position. Corrections are being made.

By the way, electron beam lithography equipment uses a method that continuously scans and exposes a material with a finely focused beam, and an unblanking method that uses a shaping aperture to form a beam with a certain width into a rectangular shape. There is a method in which the beam is shot for a predetermined period of time. The present invention relates to the latter type of electron beam lithography apparatus that shoots a variable shaped electron beam onto a material and connects the shots to create a pattern.

(Problem to be Solved by the Invention) In the step-and-repeat (S/R) stage movement drawing method, shot drawing is performed after the stage is moved by a predetermined amount, and when all drawings at that position are completed, the stage is moved again. In this method, the target pattern is obtained on the entire surface of the material by repeating shot drawing by moving a predetermined number of times. With this method, vibrations remain after the stage stops.

Therefore, if drawing is performed immediately after the stage stops, the vibration of the stage during one shot will cause the shot figure to become blurred as shown in FIG. In FIG. 2, Q is a shot figure, and B is a blurred area generated around the shot figure Q. In FIG. This blur area varies depending on the sensitivity of the resist applied to the material.

For example, in order to suppress the width of such blur to 0.01 μm or less, if one shot time is 10 μSEC, the stage movement speed should be 0.01 μm/10 μSEC.
-1m/SEC or less. If the writing is postponed until the vibration after the stage stops becomes less than 1111/SEC, the writing throughput will be reduced.

The continuous stage movement method is a method in which shot drawing is repeated while the stage is moved by a predetermined amount to obtain a desired pattern on the entire surface of the material. In this method, for example, 1μ
The shape blur is o, oi for the shot time of SEC.
In order to keep it below μm, the stage should be 0.01μII
The movement speed must be less than /1μSEC-10m/SEC.

As explained above, in the conventional method, for medium- to low-sensitivity resists, the stage movement speed must be restricted from the viewpoint of preventing blurring of shot figures rather than the pattern density. Therefore, in order to achieve high-precision drawing, the drawing throughput had to be reduced.

The present invention has been made in view of these points, and
The purpose is to realize a shot control circuit for an electron beam lithography system that can increase the lithography throughput without reducing the lithography quality.

(Means for Solving the Problems) The present invention solves the above problems by unblanking a variable-shaped electron beam and performing a beam shot on a material placed on a stage for a predetermined period of time. In an electron beam lithography system that creates a pattern by connecting beam shots, a shot dividing circuit is installed to receive externally set shot time information and divide one shot into multiple shots. 1
The present invention is characterized in that one shot is divided into a plurality of shots, and the stage position is corrected for each shot.

(Function) The conventional one shot is divided into multiple shots.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In the figure, 1 is an electron gun that emits an electron beam Bi;
is a blanking electrode that controls on/off of the emitted electron beam Bi. The blanking electrode 2 sharply deflects the electron beam B1 so that it collides with the shielding plate 3, thereby preventing the electron beam B1 from passing through the opening 3a formed in the center of the shielding plate 3. When the voltage applied to the blanking electrode 2 is reduced to 0, the deflected electron beam Bi comes to pass through the aperture 3a again.

4 is a converging lens that converges the electron beam 3i that has passed through the aperture 3a; 5 is a first shaping aperture for creating a rectangular beam;
Similarly, 6 is a second molded aperture. An opening 5 formed in the center of these first and second molded apertures 5 and 6
By adjusting the positions of a and 5a, a rectangular beam Bi' of a desired size can be obtained. 7 is a shaping deflector which is arranged between the first and second shaping apertures 5.6 and determines the dimensions of the beam, and 8 is an electron lens which focuses the charged beam Bi that has passed through the shaping deflector 7.

9 is a rectangular beam B that has passed through the second molding aperture 6:・
10 is a positioning deflector for positioning the rectangular beam BiI.

11 is a material to which the rectangular beam BHz is irradiated; 12 is a stage on which the material 11 is placed; and 13 is a stage drive mechanism for moving the stage 12 in a predetermined direction. 14 is a laser length measuring device for measuring the position of the stage 12, and a laser mirror 15 is attached to the side of the stage 12.
A laser beam is applied to the stage 12, and the position of the stage 12 is determined by receiving the reflected light and utilizing light interference.

Reference numeral 16 designates a figure decomposition circuit that receives the output of the laser length measuring device and performs various arithmetic and control operations.A CPU 117 receives pattern data from the CPU 16 and decomposes it into small figures that can be formed using electro-optical methods.

Reference numeral 18 denotes a shot dividing circuit which receives externally set shot time information (shot dividing number, shot time) and shot figure data given from the figure decomposition circuit 17 and generates a set number of shot pulses, and its output. is applied to the blanking electrode 2 via the drive amplifier 19.

Reference numeral 20 denotes a deflection correction circuit for data relating to shot positions in the pattern data, to which the LBC value is given from CPLJ16. 21 is a DAC that converts the output of the deflection correction circuit 20 into an analog signal and drives the positioning deflector 10;
It's an amplifier. And the stage drive aSt structure 13 has a C
A stage drive signal is given from PL116. The operation of the circuit of the present invention using the device configured as described above will be explained as follows.

When a stage drive signal is applied from the CPL 116 to the stage drive mechanism 13, the stage drive mechanism 13 moves the stage 12 by a predetermined amount in a predetermined direction. The stage position after the movement and subsequent changes in the stage position are constantly measured by the laser length measuring device 14 and sent to the CPL 116.

The CPL 116 calculates the difference between the actual measured position of the stage 12 and the ideal position based on the measured value of the laser length measuring device 14 to obtain a deflection correction value (LBC value) based on the position error. and,
The pattern data to be drawn and the LBC value at that time are output.

Among the outputs of the CPU 16, pattern data enters a figure decomposition circuit 17 and is decomposed into small figures that can be formed by an electron optical system. The decomposed small figures enter the shot dividing circuit 18. On the other hand, shot time information is supplied from the outside to the shot division circuit 18, and the shot division circuit 18 divides the shot figure data supplied from the figure decomposition circuit 17 into a given number of shots, It is output to the deflection correction circuit 20.

The deflection correction circuit 20 uses this shot figure data and the LBC
correction based on the position error of the drawing data ((
IH direction correction). As a result, the deflection correction circuit 20 is placed at the stage Ii! Shot figure data with corrected errors is output. The DAC amplifier 21 converts this small figure data into an analog signal, and then drives the positioning deflector 10. As a result, the rectangular beam 81' is accurately shot onto the material 11 placed on the stage 12.

For example, if the shot time information given externally is a shot time of 10μSEC and a division number of 10,
This is generated by repeating 1 μSEC shots 10 times. As a result, the electron beam 3i is unblanked 10 times, and the small figure data is also given to the deflection correction circuit 20 10 times together with the LBC value. In this way, the blanking operation and the deflection operation are performed synchronously. According to the present invention, one normal shot is divided into a plurality of shots and a plurality of shots are performed. Therefore, the ratio of the blurred area to one shot becomes extremely small, and the blurred area to the normal one shot area becomes extremely small.

By performing such an operation, stage position correction is performed for each shot, and deflection correction is also performed for each 1 μSEC, so that the allowable stage movement speed can be increased. That is, in the case of the SZR method, it is possible to start drawing without the vibrations stopping after the stage movement stops, and in the case of the continuous movement method, the stage movement speed can be increased. In any of the above cases, the drawing throughput can be improved.

In the above description, the shot division circuit is provided after the graphic decomposition circuit, but the present invention is not limited to this. It may also be provided before the graphic decomposition circuit. Furthermore, in the above embodiment, the number of shot divisions and the shot time of the divided shots are set from the outside, but the upper limit of the shot time and the total shot time (the shot time before division) can be set from the outside. The number of divisions and the shot time after division may be calculated internally.

(Effects of the Invention) As explained in detail above, according to the present invention, the conventional one
It is possible to realize a shot control circuit for an electron beam lithography system that can increase the lithography throughput without reducing lithography accuracy by dividing a shot into multiple shots and simultaneously correcting the deflection of the stage. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a shot drawing state. 1...Electron gun 2...Blanking electrode 3
... Shielding plate 3a, 5a, 5a... Opening 4
...Focusing lens 5...First molded aperture 6
...Second molding aperture...Molding-inner device 8.9...Electronic lens 10
...Positioning deflector 11...Material 12...Stage 13...
・Stage drive circuit 14...Laser length measuring device 15...Laser mirror 16
...CPU 17...Graphic decomposition circuit 18.
... Shot division circuit 19 ... Drive amplifier 20 ... Deflection correction circuit 21
...DAC amplifier 3i...Electron beam BHz...
・Rectangular beam patent applicant JEOL Ltd. representative
Person Patent attorney Fuji Ijima 1 person outside the jurisdiction A 2nd box

Claims (1)

[Claims] In an electron beam lithography device that unblanks a variable-shaped electron beam, performs beam shots on a material placed on a stage for a predetermined period of time, and creates a pattern by connecting these beam shots.
It is characterized by a shot division circuit that divides one shot into multiple shots, which divides a normal single shot into multiple shots, and also performs stage position correction for each shot. A shot control circuit for an electron beam lithography system.