JPS59152623A - Method of charged particle ray exposure - Google Patents

Abstract

PURPOSE:To enable highly accurate exposure by a method wherein a mark of a desired shape is formed on a material by contamination, which mark is then scanned with the titled ray, thus detecting the generated informational signal, and performing the focus positioning of said ray. CONSTITUTION:An electron beam draws a cross on the material by scanning a fixed range with said beam by switching to the directions X and Y at every period of a blanking signal from a mask pattern generating circuit 9. This cross scanning with said beam is performed at many times, resulting in the deposit of contaminations, according to the times of scanning, at the part of this material irradiated with said beam, and accordingly the cross mark is formed. The secondary electrons generated accompanied with the scanning are supplied to a cathode ray tube 19 as a brightness signal, after being detected by a detector 17. Then, the microscopic image of scanning electrons at the desired region including the mark is displayed. The amount of focus deviation is obtained, and the power source 20 for an objective lens 4 is controlled in order to correct it.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a charged particle beam exposure method, and particularly relates to a charged particle beam exposure method that is optimal for exposing ultra-fine patterns. For example, when exposing an ultra-fine pattern using an electron beam exposure device, the temperature of the electron beam 11 on the material to be exposed is 0.
It is necessary to set it to about 01-. In order to obtain such a narrow beam diameter, the r of the final stage electron lens and the material must be adjusted. 1
The distance must be narrowed, but this widens the aperture angle of the electron beam and shallows the depth of focus. Normally, the surface of the material to be exposed has a displacement in the height direction of an amount of several J11. Therefore, when focusing on one point of the shrine, considerable blurring occurs on other white areas. What is the result?C
Exposed lees melon gets worse. In order to eliminate this problem, it is necessary to place uneven marks in the vicinity of each exposed area in advance (preparation). (Although it is fine to focus, the material has a concave and convex hole (J-(Also, the mark is covered by the lens I~, so there is a concave part on the mark))・The last is good. Obtain scanning electron microscopy images,
It will be difficult to match the A-marks with C's scratches.
Assigning marks and numbers to j in advance requires a great deal of effort.

[Objective] The present invention has been made in view of the above-mentioned points, and is to provide a vrJ particle beam exposure method that can easily focus a charged particle beam and perform high-precision exposure. With the goal.

[Structure of the Invention] The charged particle beam exposure method based on the present invention irradiates the surface of a material to be exposed in the vicinity of the area to be exposed with a charged particle beam many times to prevent contamination on the surface of the C core material. After forming the mark, the charged particle beam is scanned in the mark portion, an information signal generated from the portion is detected based on the scanning, and the charged particle beam is detected based on the detection signal. The method is characterized in that the lines are focused, and after the focusing, the area is exposed.

Embodiment J An embodiment of the present invention will be described in detail below with reference to the attached 14 drawings.

FIG. 1 shows an example of an electron beam exposure apparatus for implementing the present invention, and 1 is an electron gun.

The electron beam generated by the electron gun 1 is passed through a focusing lens 2.
3 and an objective lens 4, the light is narrowly focused onto the surface of the material to be exposed 6 placed on the stage 5. The electron beam is irradiated onto the material 6 in response to a blanking signal supplied to the blanking electrode 7, or its irradiation is blocked, and further in response to a deflection signal supplied to an electrostatic deflector 8. The irradiation position on the material is varied.

The blanking electrode 7 includes a mark pattern generation circuit 9.
．． Scanning signal generation circuit for scanning electron microscope 10. The blanking double amount from any one of the exposure pattern generation circuits 11 is selected by the first switch circuit 12 by -C and is supplied via the amplifier 13. The electrostatic deflector 8 includes the mark pattern generation circuit 9. Scanning signal generation circuit for scanning electron microscope 10. A deflection signal from one of the exposure pattern generation circuits 11 is selected by the second switch circuit 14.

It is supplied via an amplifier 15. Part 1. The second switch circuit 12.14 is switched by (N'W'i) from the control device 16, such as an electronic computer.
2 generated from the material when irradiated with an electron beam
The secondary electrons are detected by a detector 17, and the detection signal is amplified by an amplifier 18 and then supplied to a cathode ray tube 19 as a monitor means and to the control device 16. The control device 16 also sends control signals to the excitation power source 2o of the objective lens 4 and the power source 22 of the motor 21 for moving the stage 5.

We supply “.

In the configuration as described above, first, a control signal is supplied from the control device 16 to the motor power source 22, and the stage 5 is moved a desired distance by the motor 21 to form an area (field) on the material where an ultrafine pattern is to be exposed. is distributed on the electron beam optical axis.Next, signals are supplied from the control device to the first and second switch circuits 12 and 14, and the blanking signal and deflection signal from the mark pattern generation circuit 9 are output. The switch circuits are switched so that the signals are supplied to the electrodes 7 and the deflector 8. FIG. 2 shows the blanking signal (Δ), the X-direction scanning signal (B), and The Y-direction scanning signal (C) is shown, and since the electron beam scans a predetermined range by switching between the X direction and the Y direction every cycle of the blanking signal, the electron beam draws a cross on the material. The cross-shaped scanning of the electron beam on the material is performed many times, and as a result, contamination is deposited on the electron beam irradiated part of the material according to the number of scans, and a cross-shaped mark is formed. After the cross-shaped mark is formed due to the contamination, the switch circuit 12.1 is sent from the control device 16.
The blanking signal and the scanning signal from the scanning signal generating circuit 10 for a scanning electron microscope are supplied to the electric F.
i! 7 and a deflector 8. This scanning signal is
This is two-dimensional scanning in the direction, and the secondary electrons generated along with the scanning are detected by the detector 17 and then supplied as a brightness signal to the cathode ray tube 19 to which the scanning signal is supplied. Therefore, a scanning electron microscope image of a desired area including the mark is displayed on the cathode ray tube. The secondary electron detection signal is also supplied to the control device 16, and the control device determines the amount of focus shift based on the supplied signal, and adjusts the objective lens 4 to correct the focus shift. The power supply 20 of the controller is controlled. Note that this focus correction may be performed manually by the operator while observing the scanning electron microscope image displayed on the cathode ray tube 19. After the focus is corrected, the control device 16 switches the switch circuits 12 and 14, so that the signal from the exposure pattern generation circuit 11 is supplied to the electrode 7 and the deflector 8.

The exposure pattern generation circuit stores information on how to develop an ultra-fine pattern within the field, and a writing signal corresponding to the pattern is sent to the electrodes 7. The field is supplied to a deflector 8 and a desired pattern is exposed within the field. In this pattern exposure, the electron beam irradiated on the material is 74
- It is narrowed down with the waste together - (because it is,
This can be done with extremely high precision. After the field has been exposed, the controller 16 sends a signal to the motor power supply 22 to drive the motor to move the material to expose the next field on the material. When the next field is exposed, one-two formation due to contamination that has passed through the MFf and focus adjustment using a scanning electron microscope image are performed.

Note that the present invention is not limited to the embodiments described above, and can be modified in many ways. For example, J
Although the marks are formed in the shape of a cross, the marks may have other shapes such as a straight line. In addition, it is not necessary to form a mark by tampering and perform focusing using the mark for each field, but it may be performed for multiple fields depending on the permissible area. , Separate circuits were installed to acquire the scanning electron microscope image and expose the desired pattern, but it would take a long time to do all of the above using an electronic recording machine.Furthermore, only when the first mark arrives, Do not reduce the vacuum around the exposed material.
It is possible to create an atmosphere where contamination is likely to occur. Further, in the above-mentioned embodiments, an electron beam exposure apparatus was explained as an example, but the present invention can also be applied to an ion beam exposure apparatus.

[Effects] As detailed above, the charged particle beam exposure method based on the present invention can perform the desired exposure by adjusting the focus for each field even if there is a displacement in the height direction on the material surface. In fact, it is possible to perform highly accurate exposure of ultra-fine patterns. Further, in the present invention, there is no need to take the trouble of making a large number of marks on the material in advance. Furthermore, the mark used in the present invention is placed on the lens 1- by contamination! Unlike the marks attached to the material, they are not covered by the resist, making it possible to obtain a scanning electron microscope image with good contrast of the mark part, and accurate focusing.
can be done. Furthermore, the mark provided on the lens 1- can be removed together with the resist in the upper stage of resist peeling, and the part to which the mark is attached can be used for providing other circuits, etc. .

/4, Brief explanation of the drawings Fig. 1 shows an example of an electron beam exposure apparatus for carrying out the charged particle beam exposure method based on the present invention, and Fig. 2 shows a cross mark 4-J. FIG. 2 is a diagram showing a blanking signal and a scanning signal of FIG.

1... Electron gun 4... Objective lens 5... Stage 6... Material to be exposed 7.・・・・・・Blanking electrode 8・・・・・・
... Electrostatic deflector 9 ... Mark pattern generation circuit 10 ...
. . . Scanning signal generation circuit for scanning electron microscope 11 . . . Exposure pattern generation circuit 12.1
4...Switch circuit 16...
...Control device 17...Secondary electron detector 19...
...Cathode ray tube -2, O...Objective lens power supply 21...
...Motor 22 ...Motor power supply patent applicant JEOL Ltd. Representative 9 Fuji - Husband

Claims (1)

[Claims] on the surface of the exposed material in the vicinity of the area to be exposed,
A mark of a desired shape is formed on the material F by contamination by irradiating the charged particle beam many times, and after the mark is formed, the charged particle beam C is scanned over the marked portion, and based on the scanning, the portion is・Detect information signals generated from
A charged particle beam exposure method, wherein the charged particle beam is focused U based on the detection signal, and the area is exposed after the focusing.