JPS61292322A - Electron beam transfer equipment - Google Patents

Abstract

PURPOSE:To improve the pattern transfer accuracy by forming the size of a hole of a light incident window smaller than the size of a photoelectric mask, thereby preventing the window from being charged. CONSTITUTION:When a light source 24 is fired and a shutter 25 is opened, photoelectrons in response to the pattern of a photoelectric mask 14 are discharged. The photoelectrons are focused by a magnetic field and an electric field between a sample 13 and the mask to arrive at the sample 13, thereby exposing a resist on the sample 13. Since the hole 22 of a light incident window is formed smaller than the mask 14, negative ions and electrons which arrive at an ultraviolet light passing window 23 can be extremely reduced to prevent the window 23 from being charged. Thus, a high voltage can be applied between the mask and the sample without a Penning discharge, thereby improving the pattern transfer accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electron beam transfer device that transfers a fine pattern onto a sample using a photoelectric mask.

[Technical background of the invention and its problems]

In recent years, with the increasing density of integrated circuits, the limitations of photolithography, which has been the mainstream technology for forming fine patterns, have been pointed out, and electron beam and
New line lithography is rapidly progressing. Recently, photoelectrons emitted by irradiating ultraviolet light onto a photoelectric mask placed parallel to the sample are focused onto the sample using uniform electric and magnetic fields between the sample and the mask, and the pattern on the mask is An electron beam transfer device that performs batch transfer has been developed. This device has high productivity because it is capable of high-speed transfer, the mask structure is similar to a photomask so conventional technology can be used, and the depth of focus is deep so it can transfer onto substrates with steps. It has practical advantages such as, and is extremely promising for submicron fine pattern processing. The effectiveness of such devices has been demonstrated, for example, in the literature (R. Ward, J. Vac.
Sci.

TeClIn0IOCIV, 1b (b);
Nov/Dec, 1979).

FIG. 5 is a schematic configuration diagram showing an example of the above-mentioned electron beam transfer apparatus, in which 51 is a vacuum container, 52 is a vacuum pump, 53 is a sample, 54 is a photoelectric mask, 57 is a mask support, and 58 is an insulator. 59 is a DC high voltage power supply, 60 is a focusing magnet, 61 is a magnet excitation power supply, 63 is an ultraviolet light transmitting window, and 64 is a light source. In this device, when a photoelectric mask 54 is irradiated with ultraviolet light from a light source 64, photoelectrons corresponding to the mask pattern are emitted from the mask 54, and these photoelectrons are focused by the magnetic field and electric field and placed on the sample 54.
3. As a result, the resist on the sample 53 is exposed.

In this way, the mask pattern can be transferred all at once onto the sample 53, providing the advantages described above.

By the way, in the electron beam transfer apparatus, in order to accelerate the photoelectrons emitted from the photoelectric mask 54 as described above, a negative high voltage is applied to the photoelectric mask 54 or the sample 53 is
A high positive voltage is applied to. The actual high voltage is 10-5
It is about 0 [KV]. According to experiments conducted by the present inventors, when a high negative voltage is applied to the photoelectric mask 54, a magnetic field is generated above the photoelectric mask 54, that is, in the space between the photoelectric mask 54 and the ultraviolet light transmitting window 63. It has been found that a peculiar Penning discharge is likely to occur during the test. The discharge principle of Penning discharge is described, for example, in the literature (F, M, Penning: Phys.
sica4 (1937) 71>.

FIG. 6 shows a schematic diagram of a Penning vacuum gauge that utilizes the Penning discharge principle. In the figure, 71 is a cathode, 72 is an anode, 73 is a high-voltage N source, and 74 is an arrow indicating the direction of magnetic field application. In the electron beam transfer device, electrons emitted from the support base 57 of the photoelectric mask 54 serving as a cathode ionize gas molecules in the vacuum container 51 to generate ions. Of these, the negative ions and electrons collide with the ultraviolet light transmitting window 63 and charge the window 63 negatively. If we consider the mask support stand 57 and the negatively charged window 63 to be a cathode, and the wall surface of the vacuum chamber 51 to be an anode, an electrode structure very similar to the Penning vacuum gauge shown in FIG. It will be served. This situation is shown in FIG. Penning discharge mainly occurs in the shaded area in FIG.

Furthermore, Penning discharge occurs even at a voltage lower than the voltage for accelerating electrons, for example, about 5 to 7 [KV].

When Penning discharge occurs, normal pattern transfer cannot be performed. Therefore, between the sample and the photoelectric mask,
The voltage required to obtain a pattern with good resolution (several 10
There was a problem in that it was not possible to apply KV).

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and its purpose is to prevent the occurrence of Penning discharge and to stably supply a high voltage between the mask and the sample. An object of the present invention is to provide an electron beam transfer device capable of improving pattern transfer accuracy.

[Summary of the invention]

The gist of the present invention is to prevent the light introduction window from being charged in order to create a structure in which Penning discharge does not occur.

That is, the present invention provides a vacuum container that accommodates a sample to be subjected to electron beam transfer and a photoelectric mask that is placed facing the sample and emits photoelectrons in a desired pattern when irradiated with light; A window for introducing light into the container and irradiating the photoelectric mask onto the photoelectric mask, and a means for applying a magnetic field and an electric field along a direction in which the sample and the photoelectric mask face each other, the light is applied to the photoelectric mask. An electron beam transfer device that transfers the pattern of the mask onto the sample by irradiating the sample, wherein the size of the opening of the window portion is formed to be approximately equal to or smaller than the size of the photoelectric mask. be.

〔Effect of the invention〕

According to the present invention, it is possible to extremely reduce the number of electrons emitted from the support portion of the photoelectric mask and the like reaching the window material (light transmitting plate, etc.) constituting the light introduction window portion. Therefore, it is possible to prevent the light introduction window from being charged, and it is possible to prevent Penning discharge from occurring. Therefore, a high voltage can be stably supplied between the photoelectric mask and the sample, and pattern transfer accuracy can be improved.

[Embodiments of the invention]

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a schematic configuration diagram showing an electron beam transfer apparatus according to an embodiment of the present invention. In the figure, 11 is a vacuum container, and the inside of this container 11 is evacuated by a vacuum pump 12. Inside the container 11, a sample 13 to be subjected to electron beam transfer and a photoelectric mask 14 are arranged facing each other. The sample 13 is placed on a conductive sample support 15, and the sample support 15 is fixed to the bottom of the container 11 via a support 16. As shown in FIG. 2, the photoelectric mask 14 includes a transparent plate 14a made of quartz or the like, a mask pattern 14b made of a light shielding material such as Cr formed on the lower surface of the transparent plate 14a, and a photoelectric film 14G made of Cs1 or the like deposited on the lower surface of the mask pattern 14b. The sample 13 is placed on a conductive mask support 17 having an opening approximately the same size as the sample 13. The mask support stand 17 is
The insulation is fixed to the earthen wall of the container 11 via the stone 18.

Between each of the above support stands 15 and 17, there is a DC voltage 8119
A high voltage is applied from the sample 13 to the photoelectric mask 14, thereby applying an electric field along the direction in which the sample 13 and the photoelectric mask 14 face each other. Further, a focusing magnet 20 is provided outside the container 11.

An excitation power source 21 is connected to this magnet 20, and a magnetic field is applied in the same direction as the above electric field application direction by excitation of the magnet 2o.

On the other hand, an opening 22 is provided in the clay wall of the container 11, and this opening 22 is closed to provide an ultraviolet transmitting window (light transmitting plate).
23 are provided. A light introducing window portion is formed from these openings 22 and windows 23. Here, the size of the opening of the window, that is, the size of the opening 22 is 13 in diameter.
5[awl] The photoelectric mask 14 has a diameter of 150 [#I11] for the sample 13 with a diameter of 125 [m].
It becomes.

In addition, in FIG. 1, 25 is a shutter that selectively blocks the light from the light source 24, 26 is a vibration-proof stand that holds the container 11, and 2 is a shutter that selectively blocks light from the light source 24;
Reference numeral 7 indicates a detector for detecting the relative positional relationship between the sample 13 and the photoelectric mask 14.

Next, the operation of the apparatus configured as described above will be explained.

The principle of pattern transfer is exactly the same as the conventional device. That is, when the light source 24 is turned on and the shutter 25 is opened with the sample 13 and the photoelectric mask 14 arranged as shown in FIG. 1, photoelectrons corresponding to the pattern are emitted from the photoelectric mask 14. These photoelectrons are focused by the magnetic field and electric field between the sample and the mask, reach the sample 13, and expose the resist and the like on the sample 13. As a result, the pattern of the photoelectric mask 14 is transferred onto the sample 13.

On the other hand, the principle by which Penning discharge does not occur is as follows.

Above the mask support stand 17, negative ions and electrons are generated by ionization of gas molecules, similar to the conventional apparatus. In the conventional device, negative ions and electrons generated by ionization of gas molecules above the mask support base 17 reach the ultraviolet transmitting window 23 and charge the window 23 . On the other hand, in this device, the opening 22 of the light introduction window is connected to the photoelectric mask 14 as shown in FIG.
Since the ultraviolet light transmitting window 23 is made smaller, most of the electrons reach the side wall surface of the vacuum container 11 or the periphery of the ultraviolet light transmitting window 23 (the earthen wall of the container 11). In addition, the seventh
Considering the region where Penning discharge occurs in the figure, negative ions and electrons hardly ever reach the window 23 in the structure of this device. In other words, the amount of negative ions and electrons that reach the window 23 is extremely small. Therefore, the window 23 will not be negatively charged, and the window will not serve as a cathode in the Penning vacuum gauge. Therefore, the photoelectric mask 14 is operated by the high voltage power supply 19 without causing Penning discharge.
can stably supply high voltage to the

In this way, according to this device, since the opening 22 of the light introduction window is formed smaller than the photoelectric mask 14, the amount of negative ions and electrons that reach the ultraviolet light transmitting window 23 can be extremely reduced. Therefore, charging of the window 23 can be prevented. Therefore, high voltage can be applied between the mask and the sample without causing Penning discharge.
Thereby, pattern transfer accuracy can be improved. Another advantage is that it can be easily realized simply by making the opening 22 of the light introduction window smaller than the photoelectric mask 14.

FIG. 4 is a schematic configuration diagram showing another embodiment of the present invention. Note that the same parts as in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

This embodiment differs from the previously described embodiments in that a conductive member is provided and the negative ions and electrons are transmitted through ultraviolet light.
The goal is to more reliably prevent this from happening. That is,
Immediately below the ultraviolet light transmission window 23, a conductive member 41 is provided which is formed of a cylindrical body and seven flanges projecting outward at one end of the cylindrical body. This conductive member 41 is made of aluminum, and the inner wall surface of the cylindrical body is a mirror surface. The opening (second opening) of the conductive member 41, that is, the inner diameter of the cylindrical body, is the opening 2 provided in the upper wall of the container 11.
2 (first opening), which was 130 [m]. In this case, the second opening acts as an opening of the light introduction window.

With this configuration, most of the negative ions and electrons generated by ionization of gas molecules above the mask support stand 17 reach the side wall surface of the vacuum container 11 and the conductive member 41, and the ultraviolet light transmitting window It will never reach 23. For this reason,
Window 23 is never negatively charged and does not act as a cathode in a Penning vacuum gauge.

Therefore, high voltage can be stably supplied to the photoelectric mask 14 by the high voltage power supply 19 without causing Penning discharge, and the same effects as in the previous embodiment can be obtained. Further, in this embodiment, ultraviolet light is reflected by the inner wall surface of the cylindrical body of the conductive member 41, so that the illuminance of the light irradiated onto the photoelectric mask 14 can be increased.

Note that the present invention is not limited to the embodiments described above. For example, the size of the opening of the light introduction window can be variously selected depending on the size of the charging mask used, the voltage applied between the mask and the sample, the focusing magnetic field, etc. In order to prevent the light transmitting plate from being charged, it is sufficient that the size is the same as that of the photoelectric mask or smaller than that of the photoelectric mask. However, if it is made too small, the amount of light irradiated onto the photoelectric mask will decrease, so it is only necessary to set it within a range where the amount of light necessary for electron beam transfer is irradiated onto the photoelectric mask. Further, in the embodiment shown in FIG. 4, if the opening (first opening) in the upper wall of the container is smaller than the photoelectric mask, the opening (second opening) in the conductive member is larger than the first opening. Good too. in this case,
The opening of the light introduction window is defined by the first opening. Furthermore, the material and shape of the conductive member are not limited to aluminum or circular, but other metals and other shapes can be used. In addition, various modifications can be made without departing from the gist of the present invention.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an electron beam transfer device according to an embodiment of the present invention, FIG. 2 is a sectional view showing the specific structure of a photoelectric mask used in the above device, and FIG. 3 is an operation of the above device. FIG. 4 is a schematic diagram showing another embodiment of the present invention, FIG. 5 is a schematic diagram showing a conventional electron beam transfer device, and FIG. 6 is a Penning vacuum gauge. FIG. 7 is a schematic diagram for explaining Penning discharge occurring in a conventional electron beam transfer device in comparison with a Penning vacuum gauge. 11... Vacuum container, 12... Vacuum pump, 13...
- Sample, 14... Photoelectric mask, 15... Sample support stand, 17... Mask support stand, 18... Insulating insulator, 1
9... High voltage power supply, 20... Focusing magnet, 21
... Magnet excitation power supply, 22 ... Container opening (first opening), 23 ... Ultraviolet transmission window (light transmission plate), 24
...Light source, 41... Conductive member. Applicant's representative Patent attorney Takehiko Suzue Figure 2 Figure 3 Figure 6 Figure 7

Claims (5)

[Claims] (1) A vacuum container that houses a sample to be subjected to electron beam transfer and a photoelectric mask that is placed facing the sample and emits photoelectrons in a desired pattern when irradiated with light; a window for introducing light into the photoelectric mask to irradiate the photoelectric mask; and a means for applying a magnetic field and an electric field along a direction in which the sample and the photoelectric mask face each other. In the electron beam transfer device for transferring the pattern of the mask onto the sample, the size of the opening of the window portion is formed to be approximately equal to or smaller than the size of the photoelectric mask. Electron beam transfer device. (2) The window section is formed from an opening provided in the wall surface of the container and a light transmitting plate that closes this opening, and the opening of the window section is defined by the opening in the wall surface. An electron beam transfer device according to claim 1. (3) The window portion includes a first opening provided in the wall of the container, a light transmitting plate that closes this opening, and a second opening disposed between the light transmitting plate and the photoelectric mask. 2. The electron beam transfer device according to claim 1, wherein the electron beam transfer device is formed of a conductive member having a conductive member, and an opening of the window portion is defined by a second opening of the conductive member. (4) The conductive member is formed of a plate having the second opening and a cylinder connected to the opening of the plate, and the inner surface of the cylinder reflects the irradiated light. 4. The electron beam transfer device according to claim 3, wherein the electron beam transfer device is formed to have a mirror surface. (5) Claim 3, wherein the conductive member is electrically connected to the container and grounded.
The electron beam transfer device described in Section 1.