JP2778586B2 - Electron beam lithography system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electron beam drawing apparatus used for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art In an electron beam lithography apparatus, when an external magnetic field fluctuates during writing on an object to be processed, the trajectory of the electron beam is bent, making it impossible to draw a desired pattern at a desired position. Becomes Usually, an electron beam lithography apparatus is installed in an environment where the external magnetic field fluctuation is extremely small in order to suppress unexpected positional deviation of the electron beam. However, when a magnetic object moves in the vicinity or a large current flows in the nearby power cable, the magnetic field around the electron beam writing device is disturbed, affecting the trajectory of the electron beam and causing drawing defects. I do. However, in an electron beam lithography system that repeatedly performs lithography in a minute area, it is difficult to specify a defective lithography portion even using an inspection device. Although it is conceivable to positively feed back the external magnetic field fluctuation to the deflector, this is an unrealistic technique in view of the operation speed of the electric circuit.

FIG. 4 is a block diagram showing a configuration of a conventional electron beam writing apparatus. Conventionally, an electron beam writing apparatus performs an electron gun 1 for outputting an electron beam 9, a first aperture 2 for forming the electron beam 9 in a rectangular shape, and a rotation correction, a distortion correction, and a deflection of an electron beam passing through the first aperture 2. The shaping lens 3 to be formed, the second aperture 4 for generating a desired beam shape by cutting with the first aperture, the objective lens 5 for reducing and irradiating the object 7 with the electron beam, and the electron beam 9 A column including an electron optical system including a deflector 6 for deflecting the workpiece 7 to a predetermined position, and a stage 8 for mounting and moving the workpiece 7;
A stage controller having a laser interferometer 10 for controlling the laser beam 11 for recognizing the position of the stage 8, and a drawing control for processing a signal from the laser interferometer 10 and applying a desired deflection voltage to the deflector 6 It has a system 12.

Next, the operation will be described. An electron beam 9 emitted from the electron gun 1 is shaped and deflected by the first aperture 2 and the shaping lens 3 to illuminate a desired area of the second aperture 4. Electron beam 9 after passing through second aperture 4
Is reduced by the objective lens 5 and the object 7 on the stage 8 is irradiated by the deflector 6. The position of the electron beam 9 on the workpiece 7 is determined by the signal of the laser interferometer 10 and the deflector 6.
Is calculated by the drawing control system 12 from the applied voltage (or the coordinate data of the deflection position of the electron beam). The drawing control system 12 controls the movement of the stage 8 and the applied voltage of the deflector 6 (corresponding to the deflection position of the electron beam) in order to irradiate the electron beam 9 to a desired position on the workpiece 7.

[0005]

In this conventional electron beam writing apparatus, a stage and a deflector are controlled by a writing control system, and the electron beam writing apparatus has a function of irradiating an electron beam to a desired position on an object to be processed. However, there is no means for recognizing a drawing failure caused by unintended deflection of the electron beam due to an external magnetic field fluctuation. At that time, the drawing failure must be confirmed by checking the operation of the product. Naturally, rework is impossible and the yield of the product is significantly reduced. Further, when performing a drawing failure inspection, it is extremely difficult to specify a drawing failure location due to an external magnetic field fluctuation. In particular, in a product in which a fine pattern is drawn on the entire surface, an appearance inspection or the like is impossible. In order to proactively suppress drawing defects,
The method of feeding back the external magnetic field fluctuation to the deflector is an unrealistic technique in view of the operation speed of the electric circuit and has a problem that it is not realized.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electron beam writing apparatus provided with means for facilitating checking of a writing defect due to an external magnetic field fluctuation.

[0007]

An electron beam writing apparatus according to the present invention includes an electron optical system for generating, shaping, deflecting, and irradiating an object to be processed with an electron beam, and a stage for mounting the object to be processed. A column, a stage controller that detects and moves the position of the stage, and a drawing control system that controls the electron optical system and the stage controller to perform electron beam drawing on the object to be processed. Means for detecting a change in the external magnetic field around the column to generate a signal, and receiving the detection signal of the change in the external magnetic field, calculating the position information and the deflection position information of the stage from the drawing control system. A drawing position calculator that receives and stores the coordinate data of the beam irradiation target position on the workpiece.

In this case, means may be provided for the drawing position calculator to perform a predetermined conversion on the coordinate data of the beam irradiation target position and output the coordinate data for the external inspection apparatus.

The drawing position calculator may receive the coordinate data and the drawing data of the beam irradiation target position from the drawing control system and store them.

Further, it is possible to provide a means for the drawing position calculator to perform a predetermined conversion on the coordinate data of the beam irradiation target position and the drawing data, respectively, and to output them as coordinate data and recognition data for the external inspection apparatus.

[0011] Based on the coordinate data of the beam irradiation target position, it is possible to check for a writing defect due to an external magnetic field variation on the workpiece.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the electron beam writing apparatus according to the first embodiment of the present invention.

In this embodiment, an electron gun 1 for outputting an electron beam 9, a first aperture 2 for forming the electron beam 9 in a rectangular shape, and an electron beam 9 having passed through the first aperture 2
Forming lens 3 for performing rotation correction, distortion correction and deflection of the laser beam, second aperture 4 for generating a desired beam shape by engagement with the first aperture, and electron beam 9 to be processed 7
An electron optical system composed of an objective lens 5 for reducing and irradiating an electron beam 9 and a deflector 6 for deflecting the electron beam 9 to a predetermined position on the processing object 7, and a stage 8 for moving the processing object 7 A stage control system having a built-in column, a laser interferometer 10 for controlling a laser beam 11 for recognizing the position of the stage 8, a signal from the laser interferometer 10, and a deflector 6 Drawing control system 12 for applying voltage, magnetometer 13 for recognizing external magnetic field fluctuation, signal of magnetometer 13 and drawing control system 1
Drawing position calculator 1 that outputs external output information from the information of item 2
4

Next, the operation will be described. An electron beam 9 emitted from the electron gun 1 is shaped and deflected by the first aperture 2 and the shaping lens 3 to illuminate a desired area of the second aperture 4. Electron beam 9 after passing through second aperture 4
Is reduced by the objective lens 5 and the object 7 on the stage 8 is irradiated by the deflector 6. The position of the electron beam 9 on the workpiece 7 (beam irradiation target position) is determined from the signal of the laser interferometer 10 and the applied voltage of the deflector 6 (or the coordinate data of the deflection position of the electron beam).
It is calculated by 2. The drawing control system 12 moves the stage 8 and controls the applied voltage of the deflector 6 in order to irradiate the electron beam 9 to a desired position on the workpiece 7. The magnetometer 13 constantly monitors the external magnetic field, and inputs its output to the drawing position calculator 14. The drawing position calculator 14 receives the signal from the magnetometer, and when a magnetic field fluctuation exceeding a preset allowable value occurs, the current position of the electron beam on the workpiece 7 calculated by the drawing control system 12 is calculated. Record and store the coordinate data (drawing position information) at the position 9.
The drawing position information recorded and stored by the drawing position calculator 14 is converted into stage coordinate data of an external inspection device (not shown) and then output. The external inspection device performs an appearance inspection and a measurement inspection according to the stage coordinate data obtained from the drawing position calculator 14.

FIG. 2 is a flowchart showing a processing procedure of a drawing operation using the present embodiment. First, in step 100, the electron beam lithography apparatus is started, an object to be processed such as a mask material is loaded on the stage 8, and a product operation is started. Upon receiving an instruction to start product work, the magnetometer 13
Starts outputting the external magnetic field signal to the drawing position calculator (step 101). The drawing control system 12 starts outputting the drawing position information to the drawing position calculator 14 simultaneously with the start of the drawing (step 102). The drawing position calculator 14
An external magnetic field signal is compared with a reference value to monitor whether or not the external magnetic field fluctuates. If the external magnetic field signal exceeds the reference value, it is determined that there is an external magnetic field fluctuation exceeding an allowable value (step 1).
03), the writing position information at that time (coordinate data of the beam irradiation target position; the actual beam irradiation position is deviated from this by the influence of the fluctuation of the external magnetic field) is recorded and stored (step 104). Steps 103, 10 until the drawing end instruction is issued from the drawing control system 12.
Continue with 4. When the drawing control system 12 stops (step 106), the monitoring of the external magnetic field fluctuation ends (step 107). After the drawing is completed, the drawing position calculator 1 converts the already recorded and stored drawing position coordinates into coordinate data conforming to the coordinate system of the external inspection device (step 108). The converted coordinate data is output to the external inspection apparatus as inspection target coordinate data (step 10).
9). Finally, the work is finished by removing the workpiece from the column (step 110).

From the above operation, the defective drawing position due to the fluctuation of the external magnetic field can be specified to some extent in the electron beam drawing apparatus for each object to be processed, and the range in which the external inspection apparatus performs the appearance inspection and the measurement inspection can be narrowed. Drawing defects can be easily found. As a result, even if the product has an extremely fine pattern, it is possible to determine the reprocessing of the product processing, and the yield of the product is improved as the standard becomes stricter.

Specifically, the above-described drawing failure occurs even when a ball-point pen is used near the lens barrel (column) of the electron beam drawing apparatus, or when a train or track is used far away from the outside. At least in such an environment,
Product defects can be avoided.

Next, a second embodiment of the present invention will be described.

In the present embodiment, the drawing position calculator 14 shown in FIG. 1 handles not only the coordinate data (drawing position information) of the beam irradiation target position when the external magnetic field fluctuation exceeds the allowable value but also the drawing position information. The drawing data to be processed is also received from the drawing control system 12 and stored. Others are the same as in the first embodiment.

That is, the magnetometer 13 constantly monitors the external magnetic field and inputs its output to the drawing position calculator 14. The drawing position calculator 14 receives the signal of the magnetometer and, when a magnetic field fluctuation exceeding a preset allowable value occurs,
The current coordinate data of the target position of the electron beam irradiation on the workpiece 7 calculated by the drawing control system 12 is recorded and stored. At the same time, the drawing data corresponding to the drawing position information is also recorded and stored. The drawing position information recorded and stored by the drawing position calculator 14 is converted into stage coordinates of an external inspection device (not shown), and at the same time, the drawing data is also converted into recognition data of the inspection device. Is output. The external inspection apparatus uses the stage coordinates and the recognition data obtained from the drawing position calculator 14 to automatically compare the drawing result with the drawing data.

FIG. 3 is a flowchart showing a processing procedure of a drawing operation using the second embodiment of the present invention.

Instruction to start product work (step 100)
Thereafter, the magnetometer 13 and the writing control system 12 output the external magnetic field signal and the writing position information to the writing position calculator 14 (steps 101 and 102A). When the fluctuation of the external magnetic field exceeds a preset allowable value (Step 10
3) The recording and storage of the drawing position information and the drawing data are performed by the drawing position calculator 13 (steps 104-1, 104).
-2). After the drawing is completed, the drawing position calculator 13 converts the already recorded and stored drawing position coordinates into coordinate data conforming to the coordinate system of the external inspection device (step 10).
8). At the same time, the drawing data is converted into a data format understood by the external measuring instrument (step 111). The converted coordinate data is output to the external inspection apparatus as inspection target coordinate data, and similarly, drawing data corresponding to the inspection target coordinate data is output as a drawing database (recognition data) for comparison inspection (step 109A). The external inspection apparatus specifies an inspection location from the inspection target coordinate data and compares the inspection location with a virtual pattern obtained from the comparative inspection drawing data.

From the above operation, the electron beam lithography apparatus can identify a drawing defect portion due to an external magnetic field fluctuation for each object to be processed, and the appearance inspection and the measurement inspection of the portion where the drawing defect is expected by connecting to an external inspection device. Is more easily performed. As a result, even if the product has an extremely fine pattern, it is possible to determine the reprocessing of the product processing, and the yield of the product is improved as the standard becomes stricter.

[0024]

As described above, the electron beam writing apparatus according to the present invention has a magnetic field measuring device for monitoring an external magnetic field and a writing position for recording, storing, and outputting to an external inspection apparatus the writing position when the external magnetic field fluctuates. By having a computer, a drawing failure location due to an external magnetic field fluctuation can be specified for each workpiece, and an external inspection device can easily perform an appearance inspection and a measurement inspection of a location where a rendering failure is expected. As a result, even if the product has an extremely fine pattern, it is possible to determine the reprocessing of the product processing, and the yield of the product is improved as the standard is more severe.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electron beam writing apparatus according to the present invention.

FIG. 2 is a flowchart illustrating a processing procedure of a drawing operation using the first embodiment of the present invention.

FIG. 3 is a flowchart showing a processing procedure of a drawing operation using the second embodiment of the present invention.

FIG. 4 is a block diagram showing a conventional electron beam writing apparatus.

[Explanation of symbols]

Reference Signs List 1 electron gun 2 first aperture 3 forming lens 4 second aperture 5 objective lens 6 deflector 7 workpiece 8 stage 9 electron beam 10 laser interferometer 11 laser beam 12 drawing control system 13 magnetometer 14 drawing position calculator 100 to 100 111, 102A, 104-1, 104-2,
109A Step number

Claims (4)

(57) [Claims] An electron optical system for generating, shaping, deflecting, and irradiating an object to be processed with an electron beam and a column having a stage on which the object is mounted, and a stage for detecting and moving the position of the stage A controller, and an electron beam drawing apparatus having a drawing control system that controls the electron optical system and the stage controller to perform electron beam drawing on the object to be processed, by detecting a change in an external magnetic field around the column. Means for generating a signal, and receiving the detection signal of the external magnetic field fluctuation, calculating coordinate data of a beam irradiation target position on the workpiece to be calculated from the position information and deflection position information of the stage from the drawing control system. An electron beam drawing apparatus, comprising: a drawing position calculator for receiving and storing. 2. The electron beam writing apparatus according to claim 1, further comprising means for performing a predetermined conversion on the coordinate data of the beam irradiation target position and outputting the coordinate data as coordinate data for an external inspection apparatus. 3. The electron beam drawing apparatus according to claim 1, wherein the drawing position calculator receives the coordinate data of the beam irradiation target position and the drawing data from the drawing control system and stores them. 4. The apparatus according to claim 3, further comprising means for performing a predetermined conversion on the coordinate data of the beam irradiation target position and the drawing data, respectively, and outputting the coordinate data and the recognition data for the external inspection apparatus. Electron beam drawing equipment.