JP2005086092A - Exposure mask container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure mask container which prevents a trouble caused by misplacement of the mask container and improves the productivity of a semiconductor fabrication system by attaching a bar code to manage an exposure mask used for the semiconductor fabrication system directly to the mask not to the mask container. <P>SOLUTION: The exposure mask container 20 which holds the exposure mask 50 comprises an upper lid part 22, a lower lid part 21 that is connected to the upper lid portion so that space may be formed inside, a sealing means to seal the upper lid part 22 and the lower lid part 21, and holding means 23, 24, 27 provided at the upper lid part 22 or the lower lid part 22 to hold the exposure mask at a predetermined position. A transparent part through which the bar code 52 attached to the exposure mask 50 is read from an outside is provided on at least either the upper lid part or the lower lid part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exposure mask container for storing an exposure mask, and more particularly to an exposure mask container for holding an exposure mask used in an electron beam exposure apparatus in a vacuum state.

  The degree of integration of a semiconductor integrated circuit is defined by a fine processing technique, and higher performance is required for the fine processing technique. In particular, in the exposure technique, a technical limit of photolithography used for a stepper or the like is expected, and further miniaturization is difficult. Electron beam exposure technology has attracted attention as a technology that breaks this limit.

  The electron beam exposure needs to be performed in a vacuum, and is shaped by passing the electron beam through the opening pattern of the exposure mask. Therefore, an exposure mask is indispensable.

  Electron beam exposure generally has a problem of low throughput. In Patent Document 1 below, a sample (wafer) coated with a photosensitive agent (resist) is placed close to a stencil mask having the same opening pattern as the exposure pattern, and the mask is scanned with a large-sized electron beam. A proximity exposure type electron beam exposure technique that completes exposure in a short time is disclosed. The present invention is not limited to an exposure method as long as it is an exposure mask used in an electron beam exposure apparatus, but here, an electron beam exposure technique of a proximity exposure method will be described as an example.

  FIG. 4 is a view showing a basic configuration of a proximity exposure type electron beam exposure apparatus disclosed in Patent Document 1. In FIG. As shown in FIG. 1, in the column 2, an electron gun unit 112 including an electron beam source 114 that generates an electron beam 115, a shaping aperture 116, and an irradiation lens 118 that converts the electron beam 115 into a parallel beam. , Including a pair of main deflectors 122 and 124, a scanning means 121 for scanning an electron beam in parallel with the optical axis, a mask 50 having an opening corresponding to a pattern to be exposed, and a sample having a resist layer 101 formed on the surface ( Semiconductor wafer) 100 is provided.

  The mask 50 has a thin film with an opening pattern formed in the center in the thick outer edge portion, and the sample 100 is arranged so that the surface is close to the mask. In this state, when an electron beam is irradiated perpendicularly to the mask, the resist layer 101 on the surface of the sample 100 is irradiated with the electron beam that has passed through the opening of the mask. When the electron beam 115 is deflected by the scanning means 121 (A, B, and C in the figure indicate beams deflected in three places) and the entire surface of the thin film on the mask 50 is scanned, all the opening patterns of the mask 50 are scanned. Will be exposed.

  The scanning means is provided with sub-deflectors 151 and 152 for slightly tilting the electron beam. The alignment of the mask 50 and the sample 100 and the displacement of the exposure position due to the mask distortion and the sample distortion. Used to correct.

  Here, the opening of the exposure mask is very fine, and if particles or dirt (contamination) adheres, the electron beam is interrupted to cause an exposure defect, or when these particles or dirt are irradiated with the electron beam. The mask 50 is charged up or damaged. For this reason, the mask 50 is normally accommodated in a highly clean vacuum container or the like until it is used.

Japanese Patent No. 2951947

  In the electron beam exposure apparatus as described above, it is necessary to match the mask to be used for exposure with the mask that is actually set in the exposure apparatus. Cannot be seen. In addition, the exposure conditions in which individual exposure masks are used vary, and it is complicated for the operator to set appropriate exposure conditions in the exposure apparatus each time. Furthermore, it is necessary to record a history such as the number of times the exposure mask is used.

Therefore, conventionally, mask management is performed by attaching a bar code or a transponder in which an identification code of each exposure mask accommodated in the container is attached to the above-described container accommodating the exposure mask.
That is, by reading the barcode attached to the container, the individual masks contained in the container are identified, and the exposure conditions suitable for the mask corresponding to the identification code are extracted from the database and automatically set. In addition, management such as recording in a database based on an identification code obtained by reading the use history of the mask is performed.

  However, since the barcode or the like, which is a conventional identifier, is attached not to the exposure mask itself to be identified but to the storage container thereof, there is a high possibility of trouble caused by an erroneous insertion of the exposure mask into the storage container.

  In view of the above circumstances, an object of the present invention is to directly manage an exposure mask to prevent troubles caused by mistakes in inserting a mask and improve the productivity of a semiconductor manufacturing apparatus such as the exposure apparatus.

  In order to achieve the above object, in the present invention, a management barcode is attached to the exposure mask itself, and the exposure mask container is provided with a transparent portion capable of reading the barcode attached to the exposure mask from the outside. I will do it.

  That is, the exposure mask container of the present invention includes an upper lid portion, a lower lid portion coupled to the upper lid portion so as to form a space therein, a sealing means for sealing the upper lid portion and the lower lid portion, and an upper lid portion Or a holding means that is provided on at least one of the lower lid portions and holds the exposure mask at a predetermined position in the space, and accommodates at least one of the upper lid portion and the lower lid portion. A transparent part that can read the barcode attached to the exposure mask from the outside is provided.

  The transparent portion for reading the barcode may be configured by making all of the upper lid portion or the lower lid portion a transparent member, but at least one of the upper lid portion or the lower lid portion, It is good also as providing the reading window which enables reading a barcode from the outside.

  In addition, when the reading window is provided in at least one of the upper lid portion and the lower lid portion, the reading window is provided so that the barcode can be read from the outside in order to maintain the sealing property of the exposure mask container. It is preferable to provide an opening, a transparent member provided in the opening, and a sealing means for sealing the transparent member and the lid.

  The reading window is arranged so that the bar code can be read from the center of the exposure mask so that the bar code can be read even if the exposure mask is received by changing the relative angle between the exposure mask with the normal direction of the mask surface as the rotation axis and the exposure mask container. It is preferable that the exposure mask region having a radius up to the code position is provided at least in a size that can be read.

  Alternatively, it is preferable that the container is provided with mask angle determining means for determining the relative angle to be a predetermined angle so that the relative angle between the exposure mask and the exposure mask container is always stored at a predetermined angle.

  As described above, by providing the exposure mask container with a transparent portion capable of reading the barcode attached to the exposure mask from the outside, it is possible to directly manage the exposure mask with the barcode attached thereto. It is possible to prevent troubles caused by mistakes in inserting the mask and improve the productivity of the semiconductor manufacturing apparatus that handles the exposure mask.

  In addition, by configuring the transparent portion as a reading window that allows the barcode to be read from the outside, the strength of the exposure mask container can be increased.

  In addition, by setting the size of the reading window so that the area of the exposure mask having a radius from the center of the exposure mask to the position of the barcode can be read, the exposure mask has the exposure mask and the exposure mask container. Even if the relative angle is changed and stored, the barcode can be read reliably.

  Furthermore, by providing a mask angle determining means for determining the relative angle between the exposure mask and the exposure mask container to a predetermined angle, it is possible to provide a reading window as small as the size of the barcode, and to accommodate the exposure mask. The strength of the vessel can be further increased. In addition, since the exposure mask is accommodated at a fixed angle at all times, it is possible to improve workability when taking out the mask.

  Hereinafter, an exposure mask container according to the present invention will be described with reference to the accompanying drawings. The present invention can be applied to any exposure mask used in a vacuum, but is particularly suitable for accommodating a mask for an electron beam proximity exposure apparatus of a proximity exposure system.

  FIG. 1 is a block diagram of an exposure mask container (mask cassette) according to a first embodiment of the present invention, FIG. 1 (A) is a side sectional view thereof, and FIG. 1 (B) is a bottom view thereof. is there.

  As shown in the drawing, the mask cassette 20 is similar to the conventional mask cassette described above with reference to FIG. 6, and the upper lid 22 and the lower lid 21 coupled to the upper lid so as to form an internal space 26 between the upper lid 22 and the upper lid 22. The O-ring 25, which is a seal member that seals the internal space 26 formed by the upper lid 22 and the lower lid 21, and the upper lid 22 and the lower lid 21, respectively, are provided to support the exposure mask 50 at three points from above and below. Support members 23, 24. In FIG. 1, one of the three support members 23 and 24 is omitted for convenience.

  Here, the exposure mask 50 has a two-dimensional barcode 52 attached to its lower surface. Correspondingly, the mask cassette 20 is provided with a reading window 30 in the lower lid 21 that allows the two-dimensional barcode 52 to be read from the outside of the mask cassette 20.

  In the two-dimensional barcode 52, for example, an identification code unique to each exposure mask is recorded in order to identify the exposure mask 50 from other exposure masks. In addition, various information such as the manufacturer, the manufacturer, the product name used, the date used, the exposure date used, the number of times of use, etc. may be recorded on the two-dimensional barcode as necessary. .

The two-dimensional barcode 52 is preferably stamped by means such as edging during the manufacturing process of the exposure mask 50, or is stamped by means such as a laser marker after the manufacturing process.
In this specification, the two-dimensional barcode 52 is described as an example. However, the present invention is not limited to any identifier as long as it is an optically readable identifier such as another one-dimensional barcode. Even the exposure mask 50 is applicable.

  Further, in the present embodiment, the reading window 30 is provided on the lower lid 21 corresponding to the exposure mask 50 having the lower surface with the two-dimensional barcode 52 attached thereto, but the two-dimensional barcode 52 is attached to the upper surface of the exposure mask 50. If it is supplied, it is provided on the upper lid 22. Further, the reading window 30 may be provided on both the lower lid 21 and the upper lid 22 so that the two-dimensional barcode 52 can be applied to any surface of the exposure mask 50.

  The mask cassette 20 accommodates the exposure mask 50 in the mask cassette 20 on the mask surface (horizontal plane) so that the reading window 30 can always read the two-dimensional barcode 52 attached to the exposure mask 50. A position determining member 27 for determining the position to a predetermined position is provided.

With this position determining member 27, it is possible to set the accommodation position of the exposure mask 50 at a fixed position. However, the exposure mask 50 is accommodated in the mask cassette 20 at various relative angles with the normal direction of the mask surface as the rotation axis. It is thought that it is done.
Accordingly, even when the reading window 30 is accommodated with the relative angle changed, the reading window 30 is provided with an exposure mask having a radius from the center of the exposure mask 50 to the position of the barcode 52 so that the barcode 52 can always be read. The circular area portion is provided at least at a position and size that can be read. That is, it is preferable to provide this region so as to include a region projected on the lower lid portion 21 or the upper lid portion 22 in the mask surface vertical line direction.

  Further, as illustrated, the two-dimensional barcode 52 is preferably provided in the vicinity of the mask transfer region 51 where the transfer pattern on the exposure mask 50 is provided. This is because, in the vicinity of the mask transfer area 51, a two-dimensional bar code 52 is provided in this area in order to avoid the area and contact the exposure mask 50 when the robot arm as a mask transfer device holds the exposure mask 50. This is because the two-dimensional barcode 52 can be prevented from being covered or soiled. Therefore, the reading window 30 can be used to optically read the area near the mask transfer area 51 where the transfer pattern on the exposure mask 50 is provided, so that this area can be read in the direction perpendicular to the mask surface. It is preferable to provide so as to include the region projected on the portion 22.

The reading window 30 supports the opening 31 provided in the lower lid 21, the transparent member 32 made of a material such as glass provided in the opening 31, and the transparent member 32 so as not to drop off from the lower lid 21. A support member 35 attached to the lower lid 21, an O-ring 34 that seals the transparent member 32 and the lower lid 21, and an O-ring 33 that seals the transparent member 32 and the support member 35.
The support member 35 is provided with an opening like the opening 31 of the lower lid 21 so that the barcode can be read from the outside.

  By configuring the reading window 30 as described above, the barcode 52 attached to the lower surface of the exposure mask 50 can be visually read from the outside through the transparent member 32. Further, the airtightness of the mask cassette 20 can be maintained.

Next, reading of the barcode 52 of the exposure mask 50 housed in the mask cassette 20 will be described.
FIG. 2 is a view showing a configuration of a proximity exposure type electron beam exposure apparatus in which an exposure mask accommodated in the mask cassette 20 of the embodiment of the present invention is used. Although an actual exposure apparatus is provided with a wafer transfer mechanism, it is omitted in FIG. 2 for simplicity.

  In FIG. 2, solid arrows indicate the exposure mask transport path. Reference numeral 1 denotes a vacuum chamber, which is provided with an electron beam optical system as shown in FIG. The inside of the vacuum chamber 1 is maintained in a high vacuum state, and a moving mechanism for moving the wafer to be exposed is provided. The wafer held on the stage is moved directly under the exposure mask of the electron optical column 2, and when the exposure mask is operated with a large electron beam, the wafer is irradiated with the electron beam that has passed through the opening of the exposure mask, and has the same pattern as the mask. Are exposed.

The exposure mask 50 is accommodated in the mask cassette 20 and set in a portion indicated by the mask stocker 9. The mask cassette 20 is maintained in a vacuum state and at a high class of cleanliness, and is transferred to the exposure mask input / output mechanism 3 by the cassette transfer mechanism 8.
The exposure mask 50 is output from the mask cassette 20 by the exposure mask input / output mechanism 3 and is carried into a vacuum chamber inside the exposure mask input / output mechanism 3. The exposure mask 50 carried in is adjusted in position and rotational position by the mask aligner 6 by the mask transport mechanism 5, then the gate 7 is opened, transported to the lower part of the electro-optical column 2, and fixed by the electrostatic chuck. Then, the used exposure mask 50 is returned to the mask cassette 20 through the reverse path.

  Although the inside of the mask cassette and the inside of the mask transport mechanism 5 are in a vacuum state, here, the portion of the electron optical column 2 is maintained in a high vacuum state and a high cleanliness state, and for the safety of the apparatus, the gate 4 and 7 is provided. With the mask set as described above, the wafer is transferred onto the stage and exposure of the wafer is started.

  The barcode 52 of the exposure mask 50 is read by providing an imaging means such as a CCD camera below the path through which the exposure mask 50 passes at any location on the exposure mask 50 conveyance path shown in FIG. Can do. However, in order to increase the conveyance speed, it is preferable to read in advance when the mask is set on the mask stocker 9 before the conveyance is started.

  FIG. 3 is a schematic configuration diagram of the mask stocker 9. The mask stocker 9 is carried out by raising and lowering the locker 61, a case 60, a locker 61 that can move up and down in the case 61, a plurality of shelves 62 on which the mask cassette 20 is placed in the locker 61, and the locker 61. A locker elevating mechanism 63 for selecting the mask cassette 20 and positioning the mask cassette 20 at the unloading position by the cassette conveying mechanism 8 is provided.

  Each shelf 62 of the locker 61 has a reading window for optically reading the two-dimensional barcode 52 attached to the lower surface of the exposure mask 50 through the reading window 30 provided in the lower lid 21 of the mask cassette 20. Below 30, an opening 64, a CCD camera 65 which is an image pickup means, and a support means 66 for supporting the CCD camera 65 and fixing it to the shelf 62 are provided.

The CCD camera 65 images the two-dimensional barcode 52 attached to the lower surface of the exposure mask 50 through the opening 64 and the reading window 30, and outputs the image signal to a signal processing means (not shown). By this signal processing means, the image signal of the two-dimensional barcode 52 is converted into digital information such as an identification code.
The electron beam exposure apparatus identifies each mask set in the mask stocker 9 based on this identification code. Furthermore, using this identification code, various data relating to each mask (exposure conditions, product, etc., usable number of times, number of times of use, etc.) are extracted from the available mask information database.

  In the above example, each shelf 62 of the locker 61 is illustrated as having a configuration in which an opening 64 for optically reading the barcode 52 is provided below the reading window 30. However, the configuration of each shelf 62 is as follows. As long as the CCD camera 65 can optically read the barcode 52 through the reading window 30, any configuration may be used.

FIG. 4 is a block diagram of an exposure mask container (mask cassette) according to the second embodiment of the present invention, FIG. 4 (A) is a side sectional view thereof, and FIG. 4 (B) is a bottom view thereof. is there.
The mask cassette 20 shown in FIG. 4 determines the mask angle for preventing the exposure mask 50 from being stored at various relative angles with the mask surface normal direction as the rotation axis when the exposure mask 50 is stored in the mask cassette 20. The lower lid 21 is provided with a protrusion 28 as a means.
The protrusion 28 hooks the exposure mask 50 so that the relative angle between the exposure mask 50 and the mask cassette 20 becomes a predetermined angle by being hooked on the outer peripheral flat portion 53 of the exposure mask 50. The lower lid 21 is also provided with a position determining member 27 for positioning the exposure mask 50 at a predetermined position on the mask surface in the mask cassette 20.

Therefore, if the position of the barcode 52 on the exposure mask 50 is known, the barcode 52 attached to the exposure mask 50 accommodated in the mask cassette 20 by the projection 28 and the position determining member 27 is changed to the mask cassette 20. You can determine exactly where you are inside.
As a result, as shown in FIG. 4, the reading window 30 can be provided so as to be adapted to the position of the barcode 52 in the mask cassette 20, and the reading window 30 can be provided as small as the barcode 52. Thus, the strength of the mask cassette 20 can be further increased.

  By utilizing the present invention, it becomes possible to directly read an identifier such as a barcode attached to an exposure mask accommodated in an exposure mask container and directly manage the exposure mask, thereby preventing troubles caused by mistakes in inserting the mask. Thus, the productivity of the semiconductor manufacturing apparatus such as the exposure apparatus can be improved.

It is a block diagram of the mask cassette which concerns on 1st Example of this invention. It is a figure explaining the mask conveyance of an electron beam exposure apparatus. It is a block diagram of a mask stocker. It is a block diagram of the mask cassette which concerns on 2nd Example of this invention. It is a basic block diagram of an electron beam proximity exposure apparatus. It is a block diagram of the conventional mask cassette.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Mask cassette 21 ... Lower lid 22 ... Upper lid 23, 24 ... Support member 25, 33, 34 ... O-ring 27 ... Position determining member 30 ... Reading window part 31 ... Opening part 32 ... Transparent member 35 ... Support member 50 ... Mask 52 ... Two-dimensional barcode

Claims (5)

An exposure mask container for storing an exposure mask,
An upper lid,
A lower lid portion coupled to the upper lid portion so as to form a space therein;
Sealing means for sealing the upper lid portion and the lower lid portion;
A holding means provided on at least one of the upper lid and the lower lid, and holding the exposure mask at a predetermined position in the space;
At least one of the upper lid part and the lower lid part has a transparent part capable of reading a barcode attached to an exposure mask to be accommodated from the outside.   2. The exposure according to claim 1, wherein the transparent portion is a reading window provided on at least one of the upper lid portion and the lower lid portion and capable of reading the barcode from the outside. Mask container. The upper lid portion and the lower lid portion are sealed by a first sealing means,
The reading window includes an opening provided in at least one of the upper lid and the lower lid so that the barcode can be read from the outside, a transparent member provided in the opening, and the transparent The exposure mask container according to claim 2, further comprising: a second sealing unit that seals a member and the lid.   4. The reading window is provided in a size that allows at least a region of the exposure mask having a radius from the center of the exposure mask to the position of the barcode to be read. Exposure mask container.   The holding means includes mask angle determining means for determining a relative angle between the exposure mask and the exposure mask container having a normal direction of the exposure mask surface as a rotation axis to a predetermined angle. Item 4. The exposure mask container according to Item 2 or 3.

Images