JPH10261560A - Method for carrying in/out sample and device supporting carry-in/out of sample - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for carrying in and out a sample that can carry in a sample into a treatment room that is maintained in a vacuum atmosphere through a preliminary room in which pressure can be adjusted without causing a foreign object to be adhered to the sample and for example, can contribute to the realization of the local cleaning of a system for producing a mask that is used in a process for manufacturing a semiconductor device. SOLUTION: A container 24 for carrying a sample where a ventilation property is secured by a filter for eliminating dust/dirt is used, and a sample 23 is accommodated in the container 24 for carrying a sample in an atmosphere 22 that is maintained to be clean when carrying the sample 23 into a treatment room 7. After the container 24 for carrying the sample is carried into a preliminary room 3, the inside of the preliminary room 3 is evacuated to a vacuum atmosphere and then the sample 23 is taken out of the container 24 for carrying a sample and is carried into the treatment room 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for carrying a sample into and out of a treatment room maintained in a vacuum atmosphere via a preparatory chamber capable of adjusting the pressure. The present invention relates to a device for supporting implementation.

[0002]

2. Description of the Related Art As is well known, a lithography technique for transferring a mask pattern drawn on a quartz mask onto a wafer is used in a manufacturing process of a semiconductor device. In general, a charged beam drawing apparatus is used for forming a mask pattern on a mask. In this charged beam drawing apparatus, an electron beam emitted from an electron gun is shaped and reduced in a vacuum atmosphere into a desired shape, and deflection and irradiation are repeated according to pattern data with the shaped electron beam to form a pattern on a mask. Form.

[0003] In recent years, the degree of integration of semiconductor devices has been rapidly increasing, and accordingly, mask patterns used in lithography have become smaller. As described above, when the pattern size is reduced and the pattern density is increased, the amount of pattern data required for forming the mask pattern also increases. For this reason, the throughput of the charged beam drawing apparatus tends to deteriorate. In order to prevent such a decrease in throughput, it is conceivable to improve the performance of the charged beam writing apparatus, but this is not easy. Therefore, instead, efforts have been made to improve the yield of masks. That is, the idea is to secure the throughput of the entire mask production system by increasing the number of good masks with few pattern defects.

[0004] Defects in the mask pattern are caused by various causes, but are often caused by adhesion of dust. In other words, when drawing a mask with a charged beam drawing apparatus, if dust or the like, which is a shadow of the charged beam, adheres to an exposed portion on a mask substrate coated with a photosensitive agent at a time before drawing, there is a possibility that there is It becomes an unexposed part and generates a pattern defect. After the pattern is formed, the defect inspection device knows the location of the defect, the number of defects, and the like, and the pattern is corrected using the correction device based on this information. It takes a long time to perform the defect inspection again, and is therefore discarded as a defective product.

Therefore, in order to effectively improve the yield of the mask, dust or other dust adheres to the exposed portion from the time when the photosensitive agent is applied on the substrate serving as the mask to the time when drawing by the charged beam. There is a need to establish techniques and methods to avoid this.

[0006] Examples of dust that can be considered include dust floating in the air, organic substances such as skin that peels off when a mask is handled by a human, and metal powder generated from a sliding portion of the apparatus.

For this reason, in a conventional mask production site, the cleanliness of the clean room in which the mask production equipment is installed is from class 100 (100 dust per cubic meter of 0.3 μm dust) to class 10 (0.
3 μm dust is reduced to 10 or less per cubic meter). In addition, the mask coated with the photosensitive agent is applied to a foreign matter inspection device to confirm that there is no dust on the mask surface. Further, before setting the mask on the drawing device, light is obliquely applied to the mask drawing surface so that there is no foreign matter. Oblique light inspections are also being conducted to confirm this.

By the way, recently, IG (giga) DRAM
The emergence of considerable semiconductor devices is desired. In a semiconductor device having such a very high degree of integration, the width of a pattern drawn on a wafer is 0.15 μm or less. Then, when the mask pattern is actually transferred onto the wafer, a method is employed in which the mask pattern is reduced to one fourth and transferred. Therefore, the required mask pattern size is O.D. It is expected to be 6 μm or less.

When a pattern having such a size is drawn on a mask, the cleanness of the clean room is class 1
0 (0.3 μm dust per 10 cubic meters)
Is insufficient, class 1 (0.1 μm dust
Class 0.1 (0.1 per cubic meter)
An environment of about 1 μm dust per cubic meter) is required.

However, it is technically and economically difficult to realize such an environment for the entire clean room. Therefore, it is conceivable that technical and economical problems can be solved by keeping only a target minimum environment clean instead of improving the cleanness of the entire clean room. In addition, by using a foreign object inspection device with higher sensitivity and higher precision and eliminating operations such as oblique light inspection by humans, it is possible to reduce the possibility that foreign objects adhere to the mask.

However, since the charged beam drawing apparatus needs to draw a pattern on a mask in a vacuum atmosphere, the charged beam drawing apparatus is provided with a spare chamber which repeats vacuuming and atmosphericization. Is separated from the building by a seismic isolation device. For this reason, it is difficult to locally clean the space between the preliminary chamber and the external mask supply / recovery device, and the mask coated with the photosensitive agent while transporting the mask from the external mask supply / recovery device to the preliminary room. Foreign matter may adhere to the drawing surface. It is also conceivable that foreign matter is mixed in the preliminary chamber while the mask is being carried into the preliminary chamber, and when the preparatory chamber is evacuated, it flies and adheres to the drawing surface of the mask.

[0012]

As described above, the IGDR
A good quality mask is indispensable for the appearance of a semiconductor device equivalent to AM. To obtain this mask, at the time of mask production,
It is necessary to handle the mask in a cleaner atmosphere. In this case, it is not advisable to improve the cleanliness of the entire clean room, and it is desirable to adopt a so-called local cleaning method that keeps only the minimum environment to be cleaned, but it is used for pattern drawing on a mask. Since the charged beam lithography system is equipped with a preliminary chamber that repeats vacuuming and atmosphericization, this preliminary chamber and an external mask supply and
There has been a problem that it is difficult to locally clean the space between the collecting device and the collecting device.

Therefore, according to the present invention, a sample can be carried into a treatment room maintained in a vacuum atmosphere via a preparatory chamber capable of adjusting pressure without adhering foreign matter to a sample. It is an object of the present invention to provide a sample loading / unloading method and a sample loading / unloading support device that can contribute to the realization of a local cleaning method for a system for producing a mask to be used.

[0014]

In order to achieve the above object, in the method for loading and unloading a sample according to the present invention, a sample is transferred to a treatment room maintained in a vacuum atmosphere via a pressure-adjustable spare room. When loading and unloading the sample from the treatment room, use a sample transport container that is air permeable by a filter for dust removal.When loading the sample into the treatment room, keep the sample in a clean atmosphere. The sample is accommodated in the sample transport container, the sample transport container is loaded into the preliminary chamber, and then the preliminary chamber is evacuated to a vacuum atmosphere, and then the sample is removed from the sample transport container in a vacuum atmosphere. It is taken out and carried into the treatment room.

Further, in order to achieve the above object, the present invention provides a method for carrying a sample into and out of a treatment room maintained in a vacuum atmosphere via a pressure-adjustable spare room. In the supporting device, a sample transport container having a gas permeability secured by a filter for removing dust, a unit for storing the sample in the sample transport container in a clean atmosphere, and a sample Means for loading or unloading the accommodated sample transport container or the sample transport container accommodating a sample in the spare chamber into or from the spare chamber.

It is preferable that the filter of the sample transport container is provided detachably with respect to the container body. The treatment room may be a drawing room in a charged beam drawing device, and the sample may be a mask on which a pattern is drawn by the drawing device.

In the sample loading / unloading method according to the present invention and the apparatus for supporting the implementation of the method, when transporting the sample, the sample transporting container is used in which the gas permeability is ensured by the dust removal filter. I have. In the sample transport container having such a structure, it is possible to evacuate the inside of the container through a filter while keeping the sample in the sample transport container, or to set the inside of the container to atmospheric pressure. Further, even if the pressure in the container is changed as described above, since the filter is protected by the filter, dust does not enter the container from outside.

In the sample loading / unloading method according to the present invention, the sample transporting container having the above-described characteristics is used, and when the sample is loaded into the treatment room, the sample is loaded into the sample transporting container in a clean atmosphere. After the sample transport container is carried into the preliminary chamber, the preliminary chamber is evacuated to a vacuum atmosphere. Thereafter, the sample is taken out of the sample transport container in the vacuum atmosphere and transported to the treatment room.

Therefore, there is no problem even in a normal air space between the spare room and the clean air atmosphere for accommodating the sample in the sample transport container. When the sample transport container containing the sample is accommodated in the preliminary chamber and the preliminary chamber is evacuated to a vacuum atmosphere, the sample transport container is also evacuated at the same time. Of possible conditions can be produced automatically. In this case, if dust adheres to the outer surface of the sample transport container during the process of loading the sample transport container into the preliminary chamber, the attached dust also enters the preliminary chamber together with the container. However, the condition for opening the sample transport container in the preparatory chamber is when the preparatory chamber is kept in a vacuum atmosphere. In such a vacuum atmosphere, even if dust adheres to the outer surface of the container, a phenomenon that the attached dust soars due to the opening operation of the container or the like hardly occurs. Therefore, dust adhered to the outer surface of the sample transport container does not adhere to the sample in the preparatory room, and, in the end, the dust can be locally cleaned while preventing the dust and the like from adhering to the sample. .

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual view of a loading / unloading support apparatus for carrying out a sample loading / unloading method according to the present invention, and here is a conceptual view of an apparatus for supporting loading / unloading of a mask with respect to a charged beam drawing apparatus.

In FIG. 1, reference numeral 1 denotes a charged beam drawing apparatus. The charged beam lithography apparatus 1 is used to load a lithography apparatus main body 2 and a mask which is attached to the lithography apparatus main body 2 and which is a sample to the lithography apparatus main body 2, and to carry out a mask from the lithography apparatus main body 2. Spare room 3 used
And an anti-vibration device 5 provided between the charged beam drawing apparatus 1 and the floor 4 for separating the entire charged beam drawing apparatus 1 from an external vibration source.

The writing apparatus main body 2 generates an electron beam in a vacuum atmosphere, and sends the electron beam from the charged beam control chamber 6 which holds and holds a sample as a charged beam control chamber 6 for shaping and deflecting the electron beam. And a drawing room 7 as a treatment room for irradiating the charged beam to the mask.

The preliminary chamber 3 has a sample transport container 2 to be described later.
A space 8 in which the sample chamber 4 is placed, an opening / closing mechanism 9 for opening and closing the sample transfer container 24, and a gate valve 10 provided at the boundary between the drawing chamber 7 and the vacuum chamber 7 for always maintaining a vacuum atmosphere.
And a gate valve 1 provided at the boundary between the atmosphere side and a mask, that is, a sample transfer container 24 for delivery.
1 is provided. And the pressure in the preliminary chamber 3 is
A pressure control device (not shown) selectively controls the vacuum atmosphere and the atmospheric pressure to the same degree as those of the drawing chamber 7.

On the other hand, reference numeral 21 in the drawing denotes a sample carrying-in / transporting assisting device. The carry-in / transport support device 21 accommodates a local clean space device 22 having a clean air flow of class 0.1 and a mask 23 which is a sample in the local clean space device 22 in a sample transfer container 24. And a sample transport container 2 in which a mask 23 is stored.
4 is carried into the preliminary chamber 3 through the gate valve 11, or the sample transport container 24 in the preliminary chamber 3 is connected to the gate valve 1.
1 and a transfer robot 26 for transferring it to the outside.

As shown in FIG. 2, the sample transport container 24 includes a container body 28 having an opening directed downward in this example,
A lid 29 for selectively closing the opening of the container body 28 to cover the opening. The container body 28 and the lid 2
A joint (not shown) made of resin, silicone rubber, or the like is provided with a ring seal or a gasket (not shown) at the joint portion with the nozzle 9 to ensure airtightness. In addition, 4 of the container body 28
As shown in FIG. 2, holes 30 are formed in the two side walls, and a filter device 31 is detachably fixed by screws 32 so as to close these holes 30. The filter device 31 includes a fixing jig 33 and an air filter 34 supported by the fixing jig 33 and having a function of removing foreign substances having a size of, for example, 0.1 μm or more and securing air permeability. Note that, instead of the screw 32, a structure in which the filter device 31 is fixed to the container body 28 by a pressing force of a spring may be employed.

Next, an operation example of the carry-in / carrying-out support device 21 configured as described above will be described. First, when the mask 23 coated with the photosensitive agent is carried into the preliminary chamber 3, the following operation is performed.

The application of the photosensitive agent to the mask 23 is performed in a local clean space device 22 having a clean air flow of about class 0.1. Mask 23 coated with photosensitive agent
Is the sample transfer container 24 in the local clean space device 22.
Inside. Subsequently, the opening of the container body 28 in the sample transfer container 24 is hermetically closed by the lid 29. These operations are performed by the accommodation mechanism 25.

Next, the sample transfer container 24 containing the mask 23 is transferred by the transfer robot 26 to a position near the preliminary chamber 3. At this time, the gate valve 11 of the preliminary chamber 3
Is open, and the inside of the preliminary chamber 3 is at atmospheric pressure. The transfer robot 26 carries the sample transfer container 24 containing the mask 23 into the space 8 in the preliminary chamber 3.

When the sample transfer container 24 is placed in the preparatory chamber 3, the gate valve 11 on the atmosphere side is closed and the preparatory chamber 3 is closed.
Exhaust of the inside is started. Since the air permeability of the sample transport container 24 is maintained by the filter device 31, the inside of the sample transport container 24 is also evacuated. At this time, foreign matter in the preliminary chamber 3 does not enter the sample transport container 24.
Further, if the inside of the preliminary chamber 3 is evacuated, it is unlikely that the foreign matter floats. Therefore, even if the sample transport container 24 is opened, the foreign matter does not adhere to the mask 23.

The removed mask 23 is sent into the drawing chamber 7 via the gate valve 10. Then, the gate valve 10 is closed, and the mask 23 is patterned in the drawing chamber 7 by the charged beam. After the drawing, the mask 23 is accommodated in the sample transport container 24 and carried out of the preliminary chamber 3 to the outside according to a procedure reverse to the conventional procedure.
It is sent to the development and etching process.

As can be seen from the above-mentioned operation, in this example, the mask 23 is accommodated and transported in the sample transporting container 24, which is kept air-permeable by the filter device 31, so that the local clean space device is used. 22 can be used. Furthermore, since there is no need to worry about the sowing of foreign matter during the evacuation and atmosphericization in the preliminary chamber 3, there is no need to slowly perform the evacuation and atmosphericization so that the foreign matter does not soar. For this reason, when the preliminary chamber 3 is evacuated, it can be evacuated in a shorter time than in the prior art. As a result, FIG. 3 shows the change in the mask temperature when the preparatory chamber 3 is evacuated by the conventional method (broken line A) and the change in the mask temperature when the preparatory chamber 3 is evacuated by the method of this example (solid line B). As shown in comparison, in this example, the time during which the temperature of the mask 23 changes along with the adiabatic expansion is shorter <, so that the degree of temperature decrease of the mask 23 can be reduced.

When static electricity is generated on the mask surface due to the flow of air when the preliminary chamber 3 is evacuated or evacuated, there is a possibility that foreign matter is adsorbed. By installing a static eliminator or the like that emits soft X-rays or the like in the preparatory chamber 3 and evacuating and opening the sample transport container, static elimination can be performed to prevent foreign matter from adhering. Further, the method of loading and unloading the sample shown in FIGS. 1 and 2 is not limited to a charged beam drawing apparatus, and the method is carried out to a treatment room maintained in a vacuum atmosphere via a pressure-adjustable preliminary chamber. The present invention can be applied to all systems that need to carry in a sample and carry out a sample from a treatment room.

FIG. 4 shows an example of the configuration of the stage driving mechanism for moving the mask in the XY directions in the drawing chamber 7 described above. That is, a stage drive mechanism for moving the mask in the X and Y directions is provided in the drawing chamber 7, and even when dust is generated from the sliding portion of the stage drive mechanism,
It is necessary to prevent this dusting substance from adhering to the drawing area of the mask.

When dust is generated from a sliding part such as a drive transmission device or a guide mechanism operating in a vacuum atmosphere, a lubricant is conventionally applied to the sliding part in order to suppress the diffusion of the dust-producing substance. A method has been proposed. For example, Fomblin oil manufactured by Ausimont Co., Ltd. has a very low vapor pressure of 5 × 10 ⁻¹³ Torr or less / 20 ° C. when the grade can be used as a lubricating seal for ultra-high vacuum. There is oil.

Therefore, conventionally, such a low-vapor-pressure oil is thinly applied to a sliding portion of a drive transmission device or a guide mechanism to form a lubricant film to improve the slip. However, since the thickness of the formed lubricant is as thin as several molecules or the amount of oil consumed by evaporation or the like is not zero, the lubrication effect may partially be lost with time. There is. For this reason, oil is applied every time empirically obtained to compensate for the loss.

However, when lubricating oil is regularly supplemented,
If the timing of applying the oil is too late, there is a possibility that dust will be generated from the portion where the lubricating layer has been lost. If the timing of applying the oil is too early, the total amount of the lubricant added to the mechanism may be too large, and the surplus may be scattered into the drawing chamber with the operation of the mechanism.

As described above, in the method using the lubricating oil, the surplus may scatter to various parts of the drawing chamber, and it is difficult to apply the surplus amount.
A maintenance-free drive transmission device, a guide mechanism, and the like, in which a solid lubricating film such as silver, lead, or MoS _{2 is} formed by plating, vapor deposition, or sputtering, have appeared. However, such a drive transmission device and a guide mechanism using the solid lubricating film have a problem in actual use because the adhesive force of the lubricating film is weak and the life is extremely short.

The stage drive mechanism shown in FIG. 4 solves this problem. In FIG. 4, reference numeral 2 denotes the charged beam control room described in the previous example, and reference numeral 7 denotes the drawing room described in the previous example.

X in the drawing chamber 7 for holding a mask
A Y stage 41 is provided. Around the drawing chamber 7, lubricating oil reservoirs 43 and 44 are provided adjacent to the drawing chamber 7, and in these lubricating oil reservoirs 43 and 44, the XY stage 41 is independently driven in the XY directions. Drive mechanism 45,
46 (however, the drive mechanism 46 is not shown) are provided so as to be immersed in lubricating oil 47 having a low vapor pressure.

The driving mechanisms 45 and 46 include an LM guide 49 for restricting the moving direction of the stage 48, a motor 50 as a driving source operating in the atmosphere, and a motor for transmitting a rotating torque from the motor 50 to a vacuum. For example, a magnetic fluid seal 51 as a vacuum seal portion and a magnetic fluid seal 5
For example, a ball screw 52 serving as a feed screw mechanism that converts the rotational torque transmitted via the motor 1 into a linear driving force and transmits it to the stage 48, a position above the liquid level of the lubricating oil 47, and the drawing chamber 7. And a transmission mechanism 55 for transmitting the movement of the stage 48 to the XY stage 41 through a narrow passage 54 provided in a boundary wall 53 existing between the two.

As described above, when the sliding portions of the drive mechanisms 45 and 46 are used by always immersing them in the low vapor pressure lubricating oil 47, the lubrication of the sliding portions is always maintained satisfactorily. It is possible to prevent dust from being generated from the sliding portion for a long time. Further, since the entire sliding portion is immersed in the lubricating oil 47, it is possible to prevent the surplus portion of the lubricating oil 47 from scattering into the vacuum atmosphere by the operation of the sliding portion. Therefore, it is possible to prevent the occurrence of a mask defect caused by the drive system that drives the XY stage.

[0042]

As described above, according to the present invention,
The sample can be carried into the treatment room in a state where dust and the like are prevented from adhering to the sample, which can contribute to the realization of local cleanliness.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an example in which a sample loading / unloading method according to the present invention is applied to loading / unloading of a mask with respect to a charged beam drawing apparatus.

FIG. 2 is an exploded perspective view of a sample transport container used for carrying out the loading / unloading method.

FIG. 3 is a diagram showing a relationship between a speed at which a preliminary chamber is evacuated and a temperature change of a sample in comparison with a conventional example

FIG. 4 is a diagram for explaining an improved drive system of an XY stage provided in a drawing room.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Charge beam drawing apparatus 2 ... Drawing apparatus main body 3 ... Preliminary room 5 ... Seismic isolation apparatus 6 ... Charge beam control room 7 ... Drawing room 9 ... Opening / closing mechanism 10, 11 ... Gate valve 21 ... Carry-in / transport support apparatus 22 ... Local clean Spatial device 23 ... Mask 24 ... Sample transport container 25 ... Housing mechanism 26 ... Transport robot 28 ... Container body 29 ... Lid 31 ... Filter device 32 ... Screw 33 ... Fixing jig 34 ... Air filter 41 ... XY stage 43, 44 ... Lubricant reservoir 45,46 ... Drive mechanism 47 ... Lubricant

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Makoto Kanda 4-2-1-11 Ginza, Chuo-ku, Tokyo Inside Toshiba Machine Co., Ltd. (72) Ryoichi Hirano 4-2-1-11 Ginza, Chuo-ku, Tokyo Toshiba Inside Machine Co., Ltd. (72) Inventor Yoshiaki Tada Inside Toshiba Machine Co., Ltd. 4-2-1 Ginza, Chuo-ku, Tokyo

Claims (4)

[Claims] When a sample is carried into and out of a treatment room maintained in a vacuum atmosphere via a pressure-adjustable spare room, a filter for removing dust is used to remove air from the treatment room. Using the secured sample transport container,
When loading the sample into the treatment room, the sample is stored in the sample transport container in the atmosphere kept clean,
After loading the sample transport container into the preliminary chamber, the preliminary chamber is evacuated to a vacuum atmosphere, and then the sample is taken out of the sample transport container in the vacuum atmosphere and transported to the treatment room. Loading / unloading method of sample. 2. A filter for supporting the transfer of a sample into and out of a treatment room maintained in a vacuum atmosphere through a pressure-adjustable spare room, the filter for removing dust. A sample transport container having air permeability ensured by the means, means for accommodating a sample in the sample transport container in the air kept clean, and the sample transport container or Means for loading and unloading the sample transport container accommodating the sample in the room into or from the preliminary chamber. 3. The sample loading / unloading support device according to claim 2, wherein the filter of the sample transporting container is provided detachably with respect to the container body. 4. The apparatus according to claim 2, wherein the treatment room is a drawing chamber in a charged beam drawing apparatus, and the sample is a mask on which a pattern is drawn by the drawing apparatus. .