JP2000182561A - Electron beam drawing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically perform the operation from carry-in to carry-out while smoothly adjusting a focal point and smoothly correcting a carrying arm trajectory by irradiating the light from a side of a sample even in front of a vacuum sample chamber on the way of the carrying of the sample with a carrying arm, and confirming the thickness of the sample with an optical device. SOLUTION: Rough positioning of a glass board 8 to be carried out of a stocker 22 by a carrying arm 26G is previously performed by a centering mechanism 24 before setting the glass board 8 on a pallet inside of a vacuum container. A condition that the carrying arm 26b and the glass board 8 supported by the carrying arm do not interfere with other mechanism part on a point of shape is maintained, and the glass board 8 achieves a sample thickness detecting unit 25, and the strip monochromatic light is input from a side surface in parallel with a surface of the glass board 8, and received by a CCD element light receiver arranged at a corresponding position of the other side surface, and thickness of a sample is measured by using a voltage value or a current value. Thickness of the sample can be measured without generating a contact, and adhesion of the dust to the surface of the glass board 8 is thereby prevented, and drawing is performed. Since this measurement is performed before carrying a holder 7 to a preparatory air discharge chamber 9, sample exchanging time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to semiconductor manufacturing, and more particularly to an electron beam lithography apparatus for producing a mask and a reticle for an optical exposure apparatus with high accuracy.

[0002]

2. Description of the Related Art An electron beam drawing apparatus is an apparatus for placing a semiconductor sample of a specific size in a vacuum chamber and writing a pattern on the semiconductor sample by an electron beam. The electron beam used for writing must be focused on the sample surface. A technique for accurately setting this focus on the sample surface is disclosed in Japanese Patent Application Laid-Open No. 9-45605. This publication discloses a technique of measuring the height of a sample and correcting a focal position based on the result of the height measurement. A technique for correcting the focal length of an electron beam by detecting a change in the height of a sample as described above is also disclosed in Japanese Patent Application Laid-Open No. 56-52826.

[0003] On the other hand, there are various sizes of samples to be drawn by an electron beam lithography apparatus in addition to a general fixed sample, and an electron beam lithography apparatus capable of flexibly coping with these samples is required. Have been. For such a desire,
According to the technique disclosed in JP-A-64-635, a sample is placed at a position remote from an electron beam lithography apparatus, and a sample holder for transferring the sample to a sample chamber of the electron beam lithography apparatus is provided.
There is disclosed a technique of providing a reference pin that moves up and down in accordance with the thickness of a sample so that samples of various thicknesses can be arranged, and adjusting the height of the sample to be always constant regardless of the thickness of the sample. ing.

Japanese Utility Model Publication No. Hei 7-135141 discloses a technique for changing an electrostatic chuck substrate according to the size of a sample.

[0005]

As described above, there are various sizes of samples to be drawn by the electron beam lithography apparatus, and it is required to provide an electron beam lithography apparatus which can flexibly correspond to the samples. . On the other hand, recent semiconductor manufacturing equipment
There is a demand for automation of the apparatus from the viewpoint of improving the throughput. That is, a series of operations from sample introduction to electron beam drawing to sample unloading are performed without human intervention.

All of the techniques disclosed in the above-mentioned known examples are techniques for performing electron beam lithography on samples of various sizes, but they are not sufficient in terms of automation.

According to the present invention, in an electron beam lithography apparatus for performing electron beam lithography on samples of various sizes, a series of operations from loading of the sample to electron beam lithography or unloading the sample are automatically performed. It is an object of the present invention to provide a suitable electron beam lithography apparatus.

Another object of the present invention is to provide an electron beam lithography apparatus suitable for performing electron beam lithography on transparent substrates of various sizes.

[0009]

According to the present invention, there is provided an electron source, an electron lens for converging an electron beam emitted from the electron source, and an electron beam converged by the electron lens. In an electron beam lithography apparatus that irradiates a pattern on the sample by irradiating the sample, a vacuum sample chamber for arranging the sample to be written and, while supporting the sample, in the sample chamber while supporting the sample, A transfer arm for transferring the sample in at least a part of the movement trajectory of the sample, and irradiating light from a side of the sample into the transfer trajectory of the sample of the transfer arm to detect the thickness of the sample The present invention provides an electron beam lithography apparatus characterized by comprising a sample thickness detector for performing the above.

According to such a configuration, the thickness of the sample can be confirmed during the transfer of the sample, so that the subsequent focus adjustment and correction of the trajectory of the transfer arm for transferring the sample can be performed smoothly. Will be possible. Further, since the thickness is detected by the optical device, the lifting of dust and the like due to the operation of the mechanical detecting means can be minimized.

Further, since the thickness can be detected in front of the vacuum sample chamber, it is possible to reduce the number of components of the apparatus in the sample chamber which constantly maintains vacuum. In addition, since the thickness of the sample can be known in advance before introducing the sample into the vacuum sample chamber,
Focus correction can be performed immediately after introduction into the vacuum sample chamber, which also contributes to an improvement in throughput.

Further, in an apparatus in which a plurality of sample mounting pallets are provided in the sample exchange chamber and the pallets are formed for each sample size, at least the thickness is checked before the sample is introduced into the sample exchange chamber. Therefore, the pallet can be appropriately selected based on the confirmation, and it takes time to select the pallet, and it is possible to prevent an accident in the apparatus due to an incorrect selection.

Further, the sample thickness detector of the present invention is arranged except for a place where the light beam emitted from the light source can be caught most strongly. With this configuration, even if the substrate is a transparent glass substrate, the difference between the sample and the portion other than the sample can be remarkable, and the thickness can be accurately detected.

According to another aspect of the present invention, there is provided an electron beam writing apparatus for irradiating an electron beam emitted from the electron source onto a sample to draw a pattern.
A vacuum sample chamber for irradiating the sample with an electron beam, and a sample exchange chamber connected to the sample chamber and including a plurality of pallets for mounting the sample, wherein the pallet has a size of the sample. And / or an electron beam lithography apparatus provided with a plurality of types according to the thickness.

According to such a configuration, a sample stage having a standard corresponding to the size and thickness of the sample to be mounted is selected. For example, as shown in JP-A-64-635, pins such as pins are used. There is no need to adjust standards. Further, it is not necessary to consider a positioning error of these pins and the like. Further, even if the thickness and size of the sample are different, they can be arranged at the irradiation position of the electron beam under the same conditions, so that the drawing accuracy is improved.

In addition, since a pallet appropriately determined according to the thickness and size of the sample is used, the accuracy of positioning the sample is improved.

In order to solve the above-mentioned problems, the present invention provides an electron source and an electron beam lithography apparatus for irradiating a sample with an electron beam emitted from the electron source to draw a pattern.
A vacuum sample chamber for irradiating the sample with an electron beam, and a recognition unit for recognizing a size and / or a thickness of the sample,
A transfer arm for transferring the sample on at least a part of a movement trajectory of the sample from the outside to the vacuum sample chamber, the arm having a size of the sample recognized by the recognition unit, and / or An electron beam lithography apparatus having a function of adjusting a movement trajectory of the transfer arm according to a thickness is provided.

According to such a configuration, even if samples of various sizes are introduced, breakage of the samples at the time of transfer to the sample exchange chamber or the pallet can be prevented.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to FIG.
This will be described with reference to FIG.

FIG. 3 shows a configuration diagram of the whole electron beam drawing apparatus and a method of controlling an electron beam at the time of drawing. The electron beam emitted from the electron gun 1 is shaped into a required spot by the apertures 2a and 2b and the deflector 3a. The shaped electron beam is irradiated onto the sample (glass substrate 8) by the objective lens 4. The above components are installed in a vacuum column maintained at a high vacuum in order to constantly generate and control a stable electron beam.

The irradiation position of the electron beam is set on the sample stage 5.
And the deflector 3b. Accurate positioning of the sample stage 5 is measured by a reflector installed on the sample stage 5 and the laser interference system 13.

The sample stage 5 is set in the vacuum sample chamber 6 and has an exchange chamber 11 containing a sample exchange device for exchanging samples.
Is installed adjacent to the sample chamber 6, and a preliminary exhaust chamber 9 partitioned by a separate valve 10 is installed adjacent to the sample chamber 6. The evacuation device 12 evacuates each vacuum vessel.

The above-mentioned components are controlled by the high-voltage power supply 1
4, a lens power supply 15, a deflection control system 16, a stage / loader control system 18, a signal processing system 17, and an exhaust control system 19, and overall control is performed by a CPU 20. Here, the glass substrate 8 is a glass substrate, and the surface of the glass substrate 8 is coated with a compound whose properties change by electron beam exposure. The glass substrate is mechanically fixed to a dedicated holder 7 corresponding to its size and thickness on the main body side in a state where a predetermined drawing accuracy can be realized, and is conveyed onto the sample stage 5.

FIG. 1 is a schematic diagram of a sample transport system.

The interior of the sample exchange chamber 11 is configured so that a plurality of holders can be arranged and accommodated in a vertical direction without mutual interference, and provided in the preliminary exhaust chamber 9 and the partition wall of the sample exchange chamber 11. The holder height coincides with the height of the holder separate valve section 10 and the height that can pass through the separate valve section 37 provided on the partition wall of the vacuum sample chamber 6 and the sample exchange chamber 11. 2 arm 23b
Accordingly, a holder holding portion having a mechanism capable of raising and lowering the individual holder accommodating positions up to a position where the holder can be carried out / in without causing any shape interference with the partition wall portion is provided.

For this reason, the total number of the pre-evacuated chamber 9 and the sample exchange chamber 11 evacuated and the inside of the vacuum sample chamber 6 are total
The number of pallets equal to the number of pallets stored in the sample exchange chamber is stored. For example, if there are three stages of holder storage positions, three types of pallets will be stored.

The CPU 20 shown in FIG. 3 receives, in addition to the drawing data, information such as the size and thickness of the glass substrate 8 obtained by each of the methods described below. Control such as coincidence / non-coincidence of each holder and the type of sample is also performed.

For example, A, B, C
When three types of holders are accommodated, the preliminary exhaust chamber 9
Assuming that the type A holder has been carried out, the CPU 20 recognizes this, and thereafter determines the size and thickness of the sample to be mounted on the holder, and mounts the sample on the holder if all the elements match. Then, the subsequent operation is continued, but when the type of the holder and the sample do not match, an error is displayed and the next operation is stopped to control the apparatus to be in a standby state.

If the sample matches one of the holders B and C and there is no sample on the holder, the holder carried out into the pre-evacuation chamber 9 is replaced with a compatible holder in the sample exchange chamber, and the sample is reloaded. Perform mounting. Thus, the adjustment of the degree of vacuum in the sample exchange chamber and the preliminary exhaust chamber is not wastefully performed, and the time can be reduced.

To determine the type of the holder, for example, in the preliminary exhaust chamber 9 into which the holder is first loaded, a method of determining the combination of a plurality of holes provided on the lower surface of the holder and the protrusion pins is used. It is determined whether or not the type has been carried in, and is associated with position information indicating where in the sample exchange chamber 11 to be conveyed, the position has been accommodated.
It is possible to always monitor which type of holder has been carried out to the vacuum sample chamber 6 and the sample exchange chamber 11 in the subsequent work.

Further, the principle of sample introduction of the apparatus according to the embodiment of the present invention will be described with reference to FIG. The glass substrate 8 is taken out by the transport unit 26 from the stocker 22 storing a plurality of glass substrates in the loader 21 installed in a clean atmosphere at atmospheric pressure. At this time, for example, as shown in FIG. 12, a transfer arm 26b having a stepped sample holding unit according to the size of the glass substrate is provided on the transfer unit 26a. The trajectory of the transfer arm 26b is determined on the basis of information on the size determination of the glass substrate based on the outer shape of the stocker 22, and at the position corresponding to the size of each glass substrate in the stepped portion on the transfer arm 26b, For example, it is fixed to the transfer arm 26b by a suction chuck and transferred. In the suction chuck, the size of the glass substrate is reconfirmed by the suction sensor at the position where the suction is applied, and at the same time, it is confirmed that the transfer arm 26b and the glass substrate are securely fixed by suction. The substrate can be prevented from falling off. In order to make the size of the sample correspond to the storage position on the stocker, for example, an operation of bringing the suction chuck portion of the transfer arm into contact with all the samples in the stocker is performed in advance, and the suction sensor is operated to thereby operate the sample size. It is also possible to determine the presence and absence of a sample on the stocker. From this result, the size of the sample can be associated with the coordinates of the sample container on the stocker in the apparatus main body CPU.

Note that the size of the glass substrate is the width in the horizontal direction, and a glass substrate usually used as an exposure mask for an LSI pattern is a square having a side of about 5 inches to 8 inches. The size of the glass substrate is selected in accordance with the diameter of the wafer for LSI manufacturing in which pattern exposure is performed using the glass substrate as a mask and the type of circuit pattern. Therefore, various sizes can be considered depending on the size and type of the drawing pattern.

The size of the glass substrate using the stocker is determined by, for example, a combination of a pin-shaped contact sensor 29 and a hole (not shown) provided in the stocker 22 as shown in FIG. And so on.

A plurality of contact sensors 29 protrude from the surface of the stocker mounting table 28. When the stocker 22 is placed in this state, the contact sensor 29 where there is a hole in the bottom of the stocker 22 remains as it is, and the contact sensor 29 where there is no hole is left as it is.
Is depressed and sensed by the sensor 30. If there are a plurality of combinations of signals output from the sensors at the sensed positions, the types of stockers can be determined by the number of combinations. When the type of the stocker 22 and the size of the glass substrate 8 correspond one to one, the size of the glass substrate is indirectly determined. Although the discrimination using the protruding pin has been described as an example, a signal for discriminating whether light is blocked or transmitted using an optical sensor may be used instead of pushing the pin.

As shown in FIG. 1, the glass substrate 8 carried out of the stocker 22 by the transfer arm 26b is coarsely aligned by the centering mechanism 24 before being set on the pallet in the vacuum vessel. The centering mechanism 24 responds to the change in the size of the glass substrate by increasing or decreasing the moving distance of the pressed portion of the centering mechanism 24.

The size of the glass substrate 8 is determined by the stocker 2
Although the determination is made according to the two types, the thickness is not determined.

In order to determine the thickness of the glass substrate 8 on the stocker 22, the thickness of the sample is indirectly determined due to, for example, restrictions on the outer shape or dimensions of the stocker 22. As shown in FIG.
When a stocker having a structure capable of accommodating a plurality of types of samples in the same stocker 22 is adopted by changing the interval between the columns 27 in the middle according to the size of the glass substrate, the shape of the notch of the column 27 is changed. By designing in accordance with the sample thickness, a structure in which a thicker glass substrate 8 that does not fit the shape cannot be stored and only a sample with a thickness smaller than the set thickness can be stored can be obtained.

It is also possible to determine the type of the stocker by using the above-mentioned hole or the like provided on the outer peripheral portion of the stocker, and indirectly determine in advance the place where the samples having different thicknesses are stored. It is possible to adjust the trajectory data such as the moving height of the unloading arm 26b at the time of unloading the sample in accordance with the type of the glass substrate 8 by previously discriminating the positions where the samples having different thicknesses or different sizes are accommodated. Becomes

In order to determine the thickness of the glass substrate 8, the thickness is measured while the sample is being transferred on the transfer unit 26b or the sample is placed on a stage for measuring the thickness. For example, as shown in FIG. 13, the sample is lifted to a position where there is no interference with other mechanical components while the sample is being sucked by the transfer arm 26b and transferred from the stocker, and measurement is performed in that state. Alternatively, as shown in FIG. 14, a sample is temporarily set on a thickness measurement stage, and the thickness is measured in that state.

When judging the size and thickness of the glass substrate 8, it is necessary to pay attention to the following. The size of the LSI pattern tends to be finer as the integration and function of the LSI become higher. At present, an LSI having a wiring width of at least about 0.3 μm has been commercialized, but the width of the LSI is 0.3 μm.
In many cases, the formation of a pattern of about m 2 is performed by an optical image reduction technique. On the other hand, in the electron beam lithography apparatus to which the present invention is applied, since the target is to create a pattern having a width of 0.2 μm or less and 0.1 μm or less, work in an atmosphere with less dust is required. In particular, it is necessary to manage the prevention of dust from adhering to the surface of the glass substrate.

Therefore, it is necessary to adopt a structure which is not in contact with the measurement of the thickness of the glass substrate and which minimizes the adhesion of dust to the surface of the glass substrate 8 on which drawing is performed.

For this purpose, for example, a thickness measuring method using light listed below can be considered.

First, the trajectory of the transfer arm 26b is adjusted while the glass substrate 8 is attracted to the transfer arm 26b.
The transfer arm 26b and the glass substrate 8 supported by the transfer arm 26b are
While maintaining a state that does not interfere with other mechanical parts in shape,
Move to a measurement position set for the purpose of thickness measurement or to a stage dedicated to measurement. In this state, a band of monochromatic light is input from one side surface of the glass substrate 8 in parallel with the surface of the glass substrate 8. On the other side, a photoreceptor such as one using CCD elements arranged at a fine pitch is provided at a position corresponding to the band-like light beam.

In the thickness measurement using a pair of the light receiving portion and the light projecting portion, the light is output from the sensor corresponding to the CCD element at the position where the light is reduced or the light quantity is reduced or linearly changed. Voltage value or current value. Since the glass substrate to be measured this time is transparent and light rays are incident perpendicularly to the end face, most of the light passes through the portion other than the chamfered portion of the ridge line portion, and the thickness cannot be measured. Therefore, measurement is performed by a method using refraction of light by a glass substrate.

As shown in FIG. 15, a planar monochromatic light having a class 1 level and a peak wavelength of about 780 nm having a sufficient margin with respect to the thickness and the supporting height of the measured object has a refractive index of 1.4.
When the light is incident on the glass substrate 8 of about 6 degrees, an incident angle of 10 ° to 15 ° or more is given to the end face of the substrate, so that a planar light beam is refracted inside the substrate and changes its direction. Is not reached by the light transmitted through the.
As a result, a state equivalent to light shielding by the opaque body occurs on the light receiving unit side, and the thickness of the transparent glass substrate can be measured.

For the purpose of reducing the incident angle, a slit having a width within a range that can secure a light amount sufficient to detect a sufficient thickness on the light receiving side may be mounted on the light emitting side to reduce the thickness of the light beam surface. it can. At this time, it is more suitable to use monochromatic light as a light source because light diffusion hardly occurs. As the monochromatic light, laser light of the above-mentioned JIS standard class 1 level can be used.
It is also possible to use monochromatic light generated by the above method. The chamfer of about 45 ° applied to the upper ridge portion of the glass substrate 8 also has a refraction effect and gives refraction in a direction different from that of the refracted light at the end face in the thickness direction. Since the refraction occurs in a direction different from that of the sensor light receiving unit in the same manner as the deflection caused by the refraction of the light, the thickness measurement value is hardly affected. Furthermore, even if the deposited metal film made of metal such as chromium applied to the glass substrate surface is unevenly attached to the end face in the thickness direction, only a direct light-shielding portion without refraction is created. Has almost no effect on the measurement.

The distance between the light receiving portion and the light projecting portion of the sensor is preferably set to be about 250 mm to 350 mm in accordance with the size of the glass substrate in order to prevent interference with the mechanism around the transport unit.

In the measurement of the thickness of the glass substrate by this method,
An error may occur due to the inclination angle of the glass substrate with respect to the optical axis as shown in FIG. 16 due to the positional relationship between the sensor and the sample. To reduce this as much as possible, reduce the length of light transmitted through the glass substrate. By doing so, it is possible to reduce Δt (measurement error) = L (transmitted optical path length) · tnaβ due to the inclination angle β in FIG.

In the case of using this method, the position where light is transmitted is not necessarily limited to the part of the glass substrate 8 alone. For example, as shown in FIG. 15B, when light is transmitted through a portion including a support such as a transfer arm, an initial state is first set in a state including a light-shielding width of a portion of the transfer arm 26b. By setting the measured thickness to zero, it is possible to measure only the thickness increment while the glass substrate 8 is supported.

For measuring the thickness of the glass substrate 8, white light may be used instead of monochromatic light. Since the angle of refraction differs like a prism according to the wavelength included in the white light, a state of total refraction (total light blocking) does not occur, and some light beams can reach the light receiving side sensor. For this reason, it is also possible to detect the thickness by setting, as a threshold value, a state in which the transmitted light has changed by a certain amount, instead of determining whether the irradiation is light-shielded. However, in this method, there is a case where there is an influence of a shadow due to the glass substrate support or interference of a chromium vapor deposition film on the surface of the glass substrate wrapping around the end surface in the thickness direction of the glass substrate.

Contrary to the above-described detection of night vision mounting (light-shielding portion) with respect to the bright field (transmitted light portion), area comparison by image recognition using a CCD camera and a light source with a limited irradiation width is used. If there is, it becomes possible to detect the thickness of the glass substrate as a bright field in a dark field. A specific example will be described with reference to FIG. By setting the CCD camera 33 at an angle at which the incident light beam is derived and at a position where the light source 32 does not become the background, from the refractive angle θ determined from the refractive index of the glass substrate 8 and the wavelength of the incident light, Only light having a width that has passed through the glass substrate and has been refracted will reach the light-receiving part against a background of no dark field, so the thickness of the glass substrate can be detected by detecting this bright field. it can. In FIG. 17, the diameter of the field of view of the CCD camera 33 is denoted by b, the irradiation width of the light source 32 is denoted by a, the length of one side of the glass substrate is denoted by 1, the refraction angle is denoted by θ, and the inclination angle of the glass substrate is denoted by β.

Between these, b ≦ a and b = (l · sin
θ) / cos (β−θ).
When the distance from the center axis of the CCD camera to the end face of the light source is e, there is a constraint of (b / 2) ≦ e ≦ (ab−2).

This method is used when the end face of the glass substrate 8 is cut off at a right angle and is flat. If there is a chamfer at the ridge line, it will be affected by the refraction due to the chamfer angle, and dark areas will be formed around the images on the upper and lower surfaces of the glass substrate. Has an error on the minus side. If absolute glass substrate thickness detection is required, some correction is required.

When image recognition is used, a light-shielding object is placed on the side where the light source is disposed, instead of detecting the transmitted refracted light, so that the refraction image of the light-shielding object is used as a bright part with the bright field of the light source as a background. It can also be detected as shown in FIG. At this time, the width of the light shield 34 is a, the width of the light source is b, the length of one side of the glass substrate is 1, the refraction angle is θ, the inclination angle of the glass substrate is β,
Assuming that the diameter of the field of view of the CCD camera is b, b ≦ (a cos β) and b = (l · sin θ) / cos (β−θ) and the relation of (b + a · cos β) ≦ B as in the case of detecting refracted light. Holds. The CCD camera 33 is arranged under the condition of (b / 2) ≦ e ≦ (acosβ−b / 2), where e is the distance from the end face of the light shielding object 34 to the center axis of the CCD camera 33.

In the method of detecting the thickness of the glass substrate as a dark field in a bright field using the refraction transmission image of the light-shielding member 34, the influence of the refraction of the chamfer at the ridge portion of the glass substrate 8 or the metal substrate made of metal such as chrome is used. It is possible to avoid the influence of the light-shielding of the deposited film wrapping around the end surface of the glass substrate, and the thickness of the glass substrate 8 is measured in the same manner as in the case of thickness measurement by refraction of a monochromatic planar light beam and light using a CCD light receiving sensor. Can be detected as an absolute value.

In the method using image recognition, a light source 32 is further disposed on the side where the CCD camera 33 is disposed as shown in FIG. 19, and a light beam emitted from the light source 32 is reflected on an end face of the glass substrate 8 to form a bright portion. Alternatively, a method of detecting a bright portion by reflection in a dark field of the background may be used.

In addition to using an optical sensor, it is also possible to use an ultrasonic reflection sensor disposed on the upper surface of the glass substrate to measure the thickness based on the glass substrate support portion on the upper surface of the transport unit. However, in this case, it is necessary to take measures against the generation of dust from the sensor and the drop of the dust onto the glass substrate. This means that if the apparatus is installed in a down-flow type clean chamber as shown in FIG. 20, the dust cover provided on the glass substrate 8 and the ultrasonic source 3
5 creates an airflow having a slow wind velocity in a range that does not affect the reflected ultrasonic wave by the downflow deflector 36 provided around the opening, and separates the dust generated from the ultrasonic source 35 before it falls on the glass substrate. There is a method of flowing to a different position.

As in the apparatus according to the embodiment of the present invention, if the discrimination of the size and thickness of the mask is performed before the mask is carried into the pre-evacuation chamber 9 of the holder, it is possible to minimize the sample exchange time. Becomes This is because the process time required for vacuum evacuation from the atmospheric pressure in the preliminary evacuation is different from other unloading /
This is because this is performed by a minimum number of times, which is relatively long as compared with a step of carrying in or the like.

In order to reduce the step of increasing the pressure in the pre-evacuation chamber 9, for example, as shown in the flow chart of FIG. 22, after drawing on one sample is completed, the glass substrate 8 is moved between the sample exchange chamber 11 and the vacuum sample chamber 6. There is also a method of changing the step of exchanging the set holder 7 and subsequently performing drawing on another sample. However, in this case, the sample exchange chamber 11
Samples must be set on all internal pallets.

If the sample is set in a plurality of holders in the sample exchange chamber, for example, if a sample having a different size is set in a plurality of holders in the sample exchange chamber, it may have a common drawing pattern. For example, if the relative position on the sample is changed, it becomes possible to share at least a part of the drawing data for samples of different sizes.

Instead of providing the above-mentioned sensor outside and measuring the thickness of the sample, a method using the weight and area of the sample may be considered. For example, there is a method in which a sensor such as a strain gauge is mounted on the carry-out unit, the deflection of the carry-out unit is detected by this, and the thickness is calculated from the size of the sample determined at a stage earlier than this. However, in the method using this weight, when a sample having a small difference in thickness is determined, a case may occur in which the accuracy of strain detection is not sufficient to determine the two.

As described above, in addition to directly discriminating the thickness of the sample when the sample is present on the transport unit and when the sample is present on the stage dedicated to thickness measurement, a sample thickness detector as shown in FIG. 25 is attached to the periphery of the stocker 22, and the stocker 2
The presence / absence and thickness of the glass substrate 8 in the stocker 22 can also be detected by raising or lowering the glass substrate 2 or scanning the sample thickness detector 25 in the vertical direction. When the number of sheets to be used accommodated in the stocker increases, a large vertical movement of the stocker and the sensor is required, so that the load on the device design increases.

The thickness of the glass substrate is determined by the above method, and this information is input to the CPU 20. Thereafter, the information is compared with the information on the type of the holder in the vacuum vessel. Is displayed, and display is performed on the display system in that state. At this time, the recovery of the next operation from the preliminary exhaust chamber to the atmospheric pressure is stopped. In addition to displaying the error, the operator is asked whether or not to continue the operation, and if desired, the transport operation can be forcibly continued. Normally, an operation of returning the glass substrate to the stocker is performed by the transport unit after the user confirms the error display.

When the holder and the sample do not match, it is possible to select a method of replacing the holder carried out into the preliminary exhaust chamber with an appropriate product corresponding to the type of the sample. In this case, for example, as shown in the flowchart of FIG. 21, an error is displayed when it is determined that the shapes of the sample and the holder do not match, and after the operation of confirming whether or not to continue the operation with the user, the holder is replaced. The user performs a selection confirmation operation of whether to exchange the sample or the sample, and performs the next operation of exchanging the holder or exchanging the sample according to the user's selection at this time. Further, the apparatus can determine in advance whether or not there is an object corresponding to the sample in the holder accommodated in the apparatus, thereby automatically returning the sample to the stocker.

When the information on the thickness and size of the glass substrate matches the information on the type of the holder in the vacuum vessel, the pressure in the pre-evacuation chamber is increased from vacuum to almost the atmospheric pressure, and the pressure in the holder 7 in the pre-evacuation chamber 9 is increased. The glass substrate 8 is transported. The glass substrate 8 is positioned and held in the holder 7 by a glass substrate clamping mechanism mounted on the holder 7, and contacts two places on the sample on the holder by two electrically insulated grounding contacts. Is done. After applying a constant voltage between the ground contacts and confirming that the connection has been made reliably with a current value equal to or greater than the specified current, the preliminary exhaust chamber 9 is evacuated. When the evacuation is completed, the separate valve 10 is opened, the holder 7 holding the glass substrate 8 is transferred to the exchange chamber 11 by the first arm 23a, and the correspondence between the holder 7 and the drawing data is determined. If it is, it is transferred to the sample stage 5 inside the vacuum reference chamber by the second arm 23b. Here, a high voltage is supplied to the electrostatic chuck installed on the sample stage 5, and the holder 7 is held on the sample stage 5. The earth pin is pressed against the glass substrate by a cantilevered spring, but if a glass substrate thicker than the pallet type is installed, the cantilever-shaped spring for pressing the ground pin will protrude beyond a predetermined height. In some cases, interference occurs at the entrance of the replacement chamber around the separator valve. However, if the above-described discrimination function between the glass substrate and the holder is provided, this interference can be avoided.

FIG. 21 shows a flowchart for measuring the size and thickness of the sample by each method and controlling the transport / unloading operation.

An embodiment of the thickness detecting method is shown in FIGS.

In FIG. 6, a laser, a red LED, a CCD or the like is obliquely incident, transmitted through the glass substrate 8 by a glass substrate thickness detector 25, and the thickness of the glass substrate is determined based on an output value. In FIG. 7, the glass substrate 8 is reflected by a sample thickness detector 25 using a laser, a red LED, an ultrasonic wave, a CCD, or the like, and the thickness of the sample is determined based on an output value.

FIG. 8 shows a method of irradiating the same method from the oblique direction of the glass substrate 8.

FIG. 9 illuminates a light source such as a wide laser, red LED, or ultrasonic wave from the side in the thickness direction of the glass substrate 8, and determines the thickness of the sample based on the output value.

One embodiment of the thickness detection method in FIG. 2 is shown in FIG.
11 to FIG.

FIG. 10 shows a state in which the glass substrate 8 mounted on the stocker 22 is reflected on the side surface by a sample thickness detector 25 using a laser, a red LED, a CCD, an ultrasonic wave or the like. The detector 25 is scanned at a constant vertical speed to determine the thickness of the sample based on the length of the reflection time.

The same applies when the detector 25 is fixed and the stocker 22 is moved up and down.

FIG. 11 shows that the glass substrate 8 mounted on the stocker 22 is transmitted from the side in the thickness direction of the glass substrate 8 by a sample thickness detector 25 using a laser, a red LED, a CCD having a wide width, and the output value is obtained. To determine the thickness of the sample.

The detector 25 moves stepwise in the vertical direction so as to stop right beside the glass substrate 8.

Further, the detector 25 is fixed, and the stocker 22 is fixed.
It is the same even if is moved up and down.

[0077]

According to the present invention, in an electron beam lithography apparatus for performing electron beam lithography on samples of various sizes, a series of operations from loading of the sample to electron beam lithography or unloading of the sample are automatically performed. It is possible to realize the provision of an electron beam lithography apparatus that is suitable for performing the method.

[Brief description of the drawings]

FIG. 1 is a schematic view of a sample transfer system of an electron beam lithography apparatus of the present invention (detection of sample thickness on a transfer unit).

FIG. 2 is a schematic view of a sample transport system of the electron beam lithography apparatus of the present invention.
(Detection of sample thickness on stocker).

FIG. 3 is a schematic diagram of a control system of the electron beam drawing apparatus of the present invention.

FIG. 4 is a diagram showing an embodiment of a stocker according to the present invention.

FIG. 5 is a diagram illustrating an embodiment of a sample discriminating method based on a stocker outer shape according to the present invention.

FIG. 6 is a diagram showing an embodiment of a sample thickness determination method according to the present invention.

FIG. 7 is a diagram showing an embodiment of a method for determining a sample thickness according to the present invention (reflection sensor).

FIG. 8 is a diagram showing an embodiment of a method for determining the thickness of a sample according to the present invention (oblique incidence).

FIG. 9 is a diagram showing one embodiment of a sample thickness determination method of the present invention (transmission type sensor).

FIG. 10 is a diagram illustrating an embodiment of a sample thickness determination method according to the present invention (a reflection type detection sensor in a stocker is scanned vertically).

FIG. 11 is a diagram illustrating an embodiment of a sample thickness determination method according to the present invention (a transmission type detection sensor in a stocker portion is vertically scanned).

FIG. 12 shows an embodiment of a method for adsorbing a sample in a transport unit.

FIGS. 13A and 13B are schematic diagrams of a sample thickness measurement state by changing the upward / downward trajectory of the transfer unit, FIG. 13A is a top view, and FIG.

FIG. 14 is an embodiment of a case where a sample thickness measuring stage is provided on the apparatus.

FIG. 15 is a schematic diagram of thickness measurement by oblique light input to a sample end face and transmitted and refracted light, (a) a top view, and (b) a side view.

FIG. 16 is a schematic diagram of a tilt error of a central axis of thickness with respect to an optical axis.

FIG. 17 is a schematic diagram of a method of detecting a thickness by image recognition (bright field detection in a dark field).

FIG. 18 is a schematic view of a method of detecting a thickness by image recognition (dark field detection in a bright field).

FIG. 19 is a schematic diagram of a method for detecting a thickness by image recognition (detection of a bright field in a dark field by reflected light).

FIG. 20 is a schematic diagram illustrating an installation state of an ultrasonic sensor and a downflow drift plate.

FIG. 21 is a schematic flowchart of a function added to the device and a device operation using the function.

[Explanation of symbols]

1 ... electron gun, 2a, 2b ... stop, 3a, 3b ... deflector,
4 Objective lens 5 Sample stage 6 Vacuum sample chamber
7: holder, 8: glass substrate, 9: preliminary exhaust chamber, 10 ...
Separator valve, 11: Sample exchange chamber, 12: Vacuum exhaust device, 13: Laser interference system, 14: High voltage power supply, 1
5: lens power supply, 16: deflection control system, 17: signal processing system, 18: stage / loader control system, 19: exhaust control system, 20: CPU, 21: loader, 22: stocker, 2
3a: first arm, 23b: second arm, 24: centering mechanism, 25: sample thickness detector, 26: transport unit, 27: support column, 28: stocker mounting table, 29: contact sensor, 30: sensor, 31 ... Thickness measuring stage, 31
... thickness measuring stage, 32 ... light source, 33 ... CCD camera, 34 ... light shield, 35 ... ultrasonic source, 36 ... downflow deflector.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Tsunoda 882 Momo, Oaza-shi, Hitachinaka-shi, Ibaraki Pref. Inside the Measuring Instruments Division, Hitachi, Ltd. F-term (Reference) in the Measurement Division of Hitachi, Ltd. 2H097 AA03 BA01 BA06 CA16 DA06 LA10 5C001 AA01 AA03 CC06 5C034 BB02 BB05 BB07 BB10 5F056 AA01 BA08 BA10

Claims (11)

[Claims] An electron source, an electron lens for converging an electron beam emitted from the electron source, and an electron beam lithography for irradiating the sample with the electron beam converged by the electron lens to draw a pattern on the sample In the apparatus, a vacuum sample chamber for arranging the sample to be drawn, and supporting the sample, the sample in at least a part of the movement trajectory of the sample to reach the sample chamber while supporting the sample, An electron beam lithography apparatus comprising: a transfer arm for transferring; and a sample thickness detector for irradiating light from a side of the sample into the transfer trajectory of the transfer arm to detect a thickness of the sample. . 2. The sample according to claim 1, wherein the light source for irradiating the light from a side of the sample and the sample thickness detector are arranged along a surface direction of the sample with a movement trajectory of the sample interposed therebetween. An electron beam lithography apparatus, wherein the sample thickness detector is arranged at a position different from a direction in which the light source irradiates light. 3. The sample according to claim 1, wherein the light source for irradiating the light from the side of the sample and the sample thickness detector are arranged along a surface direction of the sample across a movement trajectory of the sample. An electron beam lithography apparatus, wherein each of the constituent elements is arranged so as to be formed on a straight line inclined with respect to the moving direction of the sample. 4. The sample transfer device according to claim 1, wherein the transfer arm is in a direction parallel to a surface direction of the sample, and one side of the sample is inclined with respect to a transfer direction of the sample. An electron beam lithography apparatus, which transports an electron beam. 5. A light source for irradiating the light from a side of the sample according to claim 4, wherein one side of the sample is
An electron beam lithography apparatus arranged to emit light from an oblique direction. 6. The sample thickness detector according to claim 1, wherein a line connecting a light source for irradiating the light from the side of the sample and the sample thickness detector is parallel to a surface of the sample. The light source and the sample thickness detector are located at a position where light from the light source detected by a detector is weaker than when the light source and the sample thickness detector are linearly arranged. An electron beam drawing apparatus, wherein the electron beam drawing apparatus is arranged. 7. An electron beam drawing apparatus for irradiating an electron beam emitted from the electron source onto a sample to draw a pattern, wherein a vacuum sample chamber for irradiating the sample with an electron beam is provided. A sample exchange chamber connected to the sample chamber and including a plurality of pallets for mounting the sample, wherein a plurality of pallets are provided according to the size and / or thickness of the sample; Characteristic electron beam lithography system. 8. An electron beam lithography apparatus according to claim 7, further comprising a transfer means for transferring said pallet between said vacuum sample chamber and said sample exchange chamber. 9. An electron beam lithography apparatus according to claim 7, further comprising a spare chamber connected to said sample exchange chamber and for transferring said sample to and from said pallet. 10. An electron beam lithography apparatus according to claim 7, further comprising a detecting means for detecting a size and / or a thickness of said sample before said sample is placed on said pallet. . 11. An electron beam source, and an electron beam lithography system for irradiating an electron beam emitted from the electron source onto a sample to draw a pattern, wherein: a vacuum sample chamber for irradiating the sample with an electron beam; Recognition means for recognizing the size and / or thickness of the sample, and a transfer arm for transferring the sample on at least a part of the movement trajectory of the sample from the outside to the vacuum sample chamber, An electron beam lithography apparatus, wherein the arm has a function of adjusting the movement trajectory of the transfer arm according to the size and / or thickness of the sample recognized by the recognition means.