JPS58212134A - Evaluating method for characteristics of specimen base for charged beam exposure apparatus - Google Patents

Abstract

PURPOSE:To enable to measure as it is efficiency in a short time at the operating time by loading the position data of a specimen base in a computer memory with the output signal of a reference clock generator as a reference from the specimen base position measuring unit of a charged beam exposure apparatus, and calculating. CONSTITUTION:A start command is simultaneously applied to a specimen base drive controller 42 and a reference clock generator 44. The specimen base of the specified axis starts moving in the specified direction, and a time counter in the generator 44 starts counting simultaneously. Subsequently, a computer 41 receives an interrupt signal from the generator 44, and when a sampling interrupt signal is applied, data sampling from a measuring unit 43 is executed, and when a motor stop interrupt signal is applied, a motor stop command is applied to the controller 42, thereby stopping the base. When receiving both the motor stop interrupt signal and the sampling end interrupt signal, a stop command is applied to the generator 44. When the times for the start of the sampling, the stop of the motor, and the end of the sampling are variously varied and set, data in the transient state and normal running state of the base are obtained.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for evaluating the characteristics of a sample stand for a charged beam exposure apparatus, which measures and evaluates and analyzes the characteristics of a charged beam gjt and a high-precision sample stand used in the apparatus. Regarding.

[Technical background of the invention and its problems] In order to draw high-precision patterns on masks, wafers, etc. using a charged beam exposure device at high speed, a sample stage is required.
1. It is necessary to meet strict riding conditions in terms of constant running characteristics, vibration characteristics, etc.

For this reason, it is essential to measure and evaluate these characteristics of the sample stage for adjustment at the time of starting up the charged beam exposure apparatus, maintenance after the start of operation, and the like.

Conventionally, measuring instruments such as accelerometers, electric micrometers, and spectrum analyzers are used to measure the characteristics of a sample stage of a charged beam exposure apparatus. During measurement, these measuring instruments and sensors are directly fixed to a sample stage in a sample chamber whose walls are maintained at a height of approximately 10-' (torr).

For convenience, it is possible to attach it to the drive mechanism outside the sample chamber, but in this case, there is a possibility that the mechanical characteristics will change from the sample table via the transmission mechanism or bellows, so it is preferable to attach it directly to the sample table. is generally taken. There were three problems with the above-mentioned method of directly attaching measuring instruments and sensors. The first is that in order to attach measuring instruments and sensors, the vacuum in the sample chamber must be broken and the sample stage must be opened. It's what I have to do. This usually involves work that simulates manual labor, such as disassembling and removing the charged beam irradiation system barrel. In addition, it takes a lot of time to restore the sample chamber to a high vacuum state after the measurement is completed.
In some cases, it may become necessary to measure and adjust the zolar meters involved in the charged beam irradiation system.

Second, because conventional measuring instruments such as accelerometers, electric micrometers, and spectrum analyzers are single-function types, each measuring instrument must be prepared according to the measurement item, and preparations must be made prior to measuring the rectangle. It is necessary to aim for Characteristic evaluation of the sample stage of a charged beam exposure apparatus requires measurement of many types of items, so it takes a lot of manpower and time to collect and prepare measuring instruments. The above two problems directly lead to the problem of prolonging the downtime of the charged beam light binding device due to poor maintenance efficiency and reducing the operating rate.

Third, the QU atmosphere changes during measurements using conventional measuring instruments, making it difficult to evaluate the characteristics as they are when the sample stage is in operation. When the sample chamber is disassembled and exposed to the atmosphere, and the charged beam irradiation system barrel is completely removed, the sample stage is in a high vacuum and is different from the state in which the charged beam irradiation system barrel is placed in the sample chamber. Show characteristics. Therefore, in conventional measurements, it has not been possible to strictly evaluate the characteristics of the sample stage in the operating state.

[Purpose of the invention]

The purpose of the present invention is to solve the problem that the characteristic evaluation of a sample stage using conventional measuring instruments requires labor and time for measurement and preparation, making it impossible to perform measurements under the same conditions as during operation. An object of the present invention is to provide a method for evaluating the characteristics of a sample stage for a charged beam exposure apparatus, which enables measurement as it is during operation.

[Key points of invention]

The present invention continuously detects the sample stage at specified time intervals from the sample stage position measuring section of a charged beam exposure apparatus, which is equipped with a sample stage drive control section that drives and controls the sample stage and a sample stage position measuring section that measures the position of the sample stage. The position 7'' of the sample stage is based on the output signal of a reference clock generator that generates a clock signal at
- Extract data in time series and store it in computer memory,
In this method, the position data information stored in the memory is processed to obtain characteristic analysis data in the time domain and frequency domain of the sample stage.

〔Effect of the invention〕

According to the present invention, the following effects (1) to (7) can be obtained.

(2) Since the length measurement system (Reede interferometer, Moiré fringes, etc.) of the charged beam exposure device can be used as is, no other measuring equipment is required. There is no need to prepare a measuring equipment or prepare for measurement. .

(2) Since the sub-length system built into the charged beam exposure device is used, manual and time-consuming operations such as disassembling the sample chamber and disassembling the electron irradiation system column are unnecessary.

(3) Characteristics of the entire length measurement system built into the charged beam exposure apparatus can be correctly evaluated in the operating state without changing the measurement environment.

(4) Data is input into computer memory and processed, so the same data can be used repeatedly for multiple interpretations.

(5) Because the software GLODARAM performs data processing, it has a wide range of processing functions and is very flexible, and it is easy to expand and change the processing functions.

(6) Characteristics of the sample stage can be evaluated with the high resolution of the length measurement system of the charged beam exposure device.

(7) A wide range of computer peripherals can be used to display graphs and create recording files.

[Embodiments of the invention]

FIG. 1 is a block diagram showing the configuration around a sample stage of a charged beam exposure apparatus. Note that parts not related to the invention are omitted. Total J! The X sample stand drive control section 3 and the YE sample stand drive control circuit 4, which are connected to the machine via the interface 2t, control the start and stop of the X motor 5 and Y motor 6, respectively, and control the X-Y sample stand 7. Money moves.

The movement of the sample stage 7 is monitored in real time by a position measuring thread consisting of a Rede interferometer. A laser beam emitted from a Rade oscillator (not shown) is reflected by mirrors 8 and 9 and enters an interferometer 10.11 to create interference light, which is received by an X receiver 12 and a Y receiver 13 to generate an original 1g The signal is converted into an electrical signal and sent to the X sample stage position measurement circuit 14 and the Y sample stage position measurement circuit j5, where it is converted into position information. Some charged beam exposure apparatuses use a moiré effect for a position measurement system, and a sample stage drive control circuit is shared between X and Y and is switched to control each motor.

However, the present invention can control the movement of the sample stage,
If a circuit that has the function of monitoring all positions has an interface with a dF calculator and can be controlled by a computer, it can be applied to all configurations regardless of the method or means used.
Kill. Therefore, in the following explanation, the X, Y sample stage drive control circuit 3, 4, 14°1
5 and related equipment are collectively called the sample stage position measurement section.

FIG. 2 is a block diagram showing a schematic configuration of the external reference clock generator. The oscillator 27 (O8C) receives a start command from the computer and outputs a /4' pulse signal. The time counter 22 (CTR) receives this input and starts counting. Since the start command to the oscillator 2 is issued at the same time as the motor start command to the sample stage drive control circuit, the time counter 22tl indicates the elapsed time from the start of the motor.

The motor stop time register zs (MST) records the time at which a motor stop command should be issued to the sample stage drive control circuit, and when it matches the contents of the time counter 22, the
! Rator,? 4 (CMP) Motor stop positive interrupt signal A is issued from 7jx. The sampling start time register 2.5 (SST) records the time to start data sampling from the sample stage 1-value foot measurement circuit, and when it matches the contents of the time counter 22, the comparator ze; (CMP) 7 The count energy (
5T) Signal CE is issued. Sampling end time ・2
The time at which r-ta sampling from the sample stage position measuring circuit is completed is recorded in the star 9s (SET), and when it matches the content of the time counter CRT 22, the controller is
! A crow/glyph end interrupt signal B is issued to the controller 29 (CMP), and at the same time a count disable signal CD is issued to the sampling period counter 27. The sampling period register 27 inputs the output signal of the oscillator 21, starts counting when the counter/toenable signal CE comes from the co/gillator 26, and the contents of the counter are stored in the sampling period register s o (SIT).
When it becomes equal to , a clear signal CLR is output from the comparator s J (CMP) and the sampling period counter 27
is cleared to 0, and at the same time a sampling interrupt signal C is issued.

Further, when the count dispersion signal CD is received from the comparator 29, the counting is stopped.

Therefore, the comparator 3 continuously outputs the sampling interrupt signal at the sampling period of the sampling period register 30 from the sampling start time set in the sampling start time register 25 to the sampling end time set in the sampling end time register 28. will occur. When the computer issues a stop command,
The oscillator 21 stops outputting the pulse signal and all operations stop. In the above description, all interrupt signals are sent to the computer.

FIG. 3 is a block diagram for explaining the principle of a method according to an embodiment of the present invention. As already mentioned, the computer 41 sends commands to the sample stage drive control section 42 to control the movement of the sample stage, and inputs data from the sample stage position measurement section 43 to know the entire position of the sample stage. Reference clock generator 44 also has the functions described above. First, the computer 41 sets the sampling start time, motor stop time, stop/bring end time, and sampling cycle values in each register in the reference clock generator 44. Next, the sample stage drive control section 4
Make the necessary settings for the drive axis (X or Y, etc.), direction (forward or backward, etc.) for 2. Complete the necessary initial settings for the sample stage position measuring section 43. All preliminary preparations are completed. Then, a motor start command is issued to the sample stage drive control unit 42, and at the same time a start command is issued to the reference clock generator 44.The sample stage on the specified axis begins to move in the specified direction, and at the same time the time in the reference clock generator 44 starts to move. The counter starts counting.After this, the computer 41 receives an interrupt signal from the reference clock generator 44, and when a sampling interrupt signal comes, it executes data sampling from the sample stage position measuring section 43, and interrupts the motor stop interrupt. When a signal is received, a motor stop command is issued to the sample stage drive control unit 42 to stop the sample stage.When both the morph stop side input signal and the bling end side input signal are received, a reference clock is generated. Vessel 44
I put out a strug beat zero.

By performing the above operations and setting the sampling start time, motor stop time, and sampling end time variously, data can be obtained in a transient state and a steady running state of the sample stage.

An example of this is shown in FIG. 4 as a diagram of speed per hour.

In Fig. 4(a), the entire running state rdl(
ts=0゜tB + t, 1 < t t + t *
) t'', (b) is in the Karo speed state (tx = 0
+ ta (ts < tl ), (e) shows the constant speed driving state (ta < tt < ts < tx ), and (d) shows the deceleration state (tl < tl , ts + td < tt ).
are r-tasanged, respectively. However, the time series r-t in each state obtained in this way is converted into velocity and acceleration data by a calculator 41 and then converted to data of velocity and acceleration.

11:1.

This can be seen in the graph of the relative position. If, for example, the X and Y r-axis are taken at the same time during sampling, the meandering seen from the other direction when one sample stage is continuously moved can be measured. Next, it is possible to examine the same wave number characteristics by Fourier transforming these r-wavelengths.After the Fourier transform, if we leave only the amplitude of the specific frequency component and perform the 7-tier inverse transform, we can obtain information about the ruru specific band in the time domain. It is possible to selectively measure signals with frequency components.Furthermore, if a special instrument is installed in the length measurement system in advance, it is also possible to measure the pitching and yawing characteristics of the sample stage.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified as shown in FIG. 5, for example.

Here, the computer 41 specifies the drive axis and drive direction to the sample stage drive control unit 42, but commands to start and stop the motor are issued from the reference clock generator 44. That is, the computer 41
When a start command is issued to the reference clock generator 44, this signal is sent to the sample stage drive control section 42 to start the motor. A motor stop interrupt signal from the reference clock generator 44 is input to the sample stage drive control section 42 to stop the motor. Further, the sampling interrupt signal of the reference clock generator 44 is sent to the sample stage position measuring section 43 and used as a signal for latching the rotor. This latch data is later read into the dt calculator 41. Normally, the sample stage drive control unit 42 and the sample stage position measurement unit 43 are designed to be controlled by a computer through the path of the total n machines 41, so as shown in FIG. In order to configure the modified application example, it is necessary to newly provide a terminal for manually inputting the control signals of these circuits as external signals. However, if this configuration is realized, it has the advantage of simplifying computer processing during data sampling.

Further, a modified application example using the configuration shown in FIG. 6 as a reference clock generator can be considered.

Here, the output of the oscillator 61 is converted to the Sansol period counter 62.
Count with . The count value is sandal period register 6
Each time it matches the same number of J (SIT), the controller 64 operates, clearing the counter 621kO, and
Sampling interrupt signal c4--sent to computer. The computer counts the number of sampling interruptions from the motor startup time and always records the current time. Then, when the current time matches the start time of sampling, data sampling is started, and sampling is started! This operation stops when it matches the ring end time. If the time matches the motor stop time, a motor stop command is issued. The time and interval at which the data sampling is executed does not necessarily have to match the contents of the sampling period register 63, and may be executed every n number of interruptions. In this modified example, the computer records the current time and compares it with the start and end times of the ringing, so the software processing tends to be complicated. There are advantages that can be applied.

In addition, various modifications can be made without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the sample stage and surroundings of a charged beam exposure apparatus, FIG. 2 is a block diagram showing a schematic configuration of a reference clock generator, and FIG. 3 is for explaining the principle of a method according to an embodiment of the present invention. , wJ4 Figures (a) to (C) are diagrams for explaining the operation of the above embodiment, and Figures 5 and 6 are block diagrams for explaining modified examples, respectively. 1...! ! -is machine, 2...interface, 3...
・XK sample stage drive control circuit, 4...Y sample stage drive control circuit, 5...X motor, 6...Y motor, 7...X
-Y sample stage, g, g, ·, mirror, 10.11 ·
...Interferometer, 12...X receiver, 13
...X receiver, 14...X sample stage position measurement circuit,
15...X sample stage position measurement circuit, 2...Oscillator,
22...Time counter, 23...Motor stop time register, 24.26.29.31...Controller 7 and rater, 25...Sampling start time register, 27...
- Sampling period counter, 28... Sampling end time register, 30. ...Sangri jig interval register 1: "ll'lゝ1 star, 41... Total J1 machine, 42... Sample stage drive control unit, 43... Sample stage position measurement unit, 44... Reference clock Generator, 6... Oscillator, 62... Sampling period counter, 63... Sampling period register, 64... Controller 7 regulator. Applicant's representative Patent attorney Takehiko Suzue■, Case display Japanese Patent Application No. 57-12301 2, Title of the invention: Method for evaluating characteristics of a sample stage for an enhanced beam exposure device 3, Relationship with the person making the amendment case Patent applicant (307) Tokyo Shibaura Electric Co., Ltd. 4, Agent Address: 17th Mori Building, 1-chome-5, Toranomon, Minato-ku, Tokyo June 28B, 1981, Day 7 Contents of amendment (a> Line 16N2 of the description: "Figure 4 (a) - ≠") It says, ``Figure 4 (a) ~ (hitting the ball with June. ・1.. ・・： 142

Claims (1)

[Claims] It is equipped with a sample stand drive control unit that drives and controls the sample stand and a sample stand position measurement unit that measures the position of the sample stand. Based on the output signal of a reference clock generator that generates a clock signal, the position of the sample stage is taken into a computer memory in chronological order, and the position data information taken into the memory is subjected to arithmetic processing. A method for evaluating characteristics of a sample stage for a charged beam light binding device, characterized in that characteristic analysis data of the time domain and frequency domain of the sample stage is obtained by using the method.