JPH07201725A - X-ray mask manufacturing device, x-ray mask manufactured by this device and semiconductor device manufacturing method using this x-ray mask - Google Patents

Abstract

PURPOSE:To provide a mask manufacturing device capable of improving the positional precision of X-ray mask and pattern precision as well as coping with the mass productivity having sufficient resolving power and fit for industrial production. CONSTITUTION:A master reticle 1 is held by suction in vertical state on one axial stage 2 capable of shifting in arrow A direction. Likewise, a working mask 4 (X ray mask) is held by suction in vertical state on a working mask chuck while a stage 6 for working mask mounting this working mask chuck is in one axial stage capable of shifting in the same direction (arrow B direction) as the reticle stage 2. In such a constitution, the fitting attitude in the manufacturing time of X-ray mask is shifted from horizontal to vertical state furthermore, the alignment method of the X-ray mask is equalized with that in the X-ray aligner so that the loading requirements for the X-ray mask in the manufacturing time and exposure time may be equalized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray mask producing apparatus used in an X-ray exposure apparatus using synchrotron radiation as a light source, and an X-ray mask produced by the X-ray mask producing apparatus.

[0002]

2. Description of the Related Art The minimum line width of the next generation 64M DRAM is 0.
For the exposure apparatus corresponding to 4 μm, a stepper that uses a conventionally used light source as an i-line and a combination of a phase shift method and a modified illumination method, or an excimer laser (for example, KrF or ArF) is used as a light source. There is a device that improves the resolution. In addition, while the conventional stepper exposure method is based on the batch exposure method, an exposure apparatus that employs a reduced mirror projection / step & scan exposure method, which performs exposure while scanning both the reticle and the wafer, has also attracted attention. There is. Further, it is expected that an electron beam (EB) exposure apparatus having a weak point in throughput will be used in a form according to the purpose such as ASIC.

However, the next generation of 256M
Although an improved version of the above-mentioned exposure apparatus can be considered as an exposure apparatus after the DRAM, an X-ray exposure apparatus using an X-ray having a short wavelength is most effective due to the limitation of the resolution performance determined by the wavelength and the lens NA. It is a candidate.

FIG. 6 is a conceptual diagram of X-ray lithography using a synchrotron radiation light having high brightness and high directivity as a light source. In the figure, a mirror 405 whose reflection surface is processed into a convex shape is arranged between an SOR light source 401 having a band-like light spread in the horizontal direction and an X-ray mask 402, and the SOR light source 401 is arranged by this mirror 405. 2 shows a batch exposure method in which X-rays 404 in the form of sheet beams from No. 3 are vertically expanded to simultaneously irradiate the entire exposure area with the X-rays 404 in the vertical direction. Thereby, the X-ray mask 402
Pattern is transferred to the wafer 403 after alignment. Both the X-ray mask 402 and the wafer 403 are held in a mask chuck and a wafer chuck (not shown) in a substantially vertical state. Regarding this suction holding method, the mask chuck is a vacuum suction method or an electromagnetic suction method, and the wafer chuck is a vacuum chuck. Adsorption method or electrostatic adsorption method is used.

As shown in FIGS. 7 and 8, the X-ray mask 402 has mask patterns 501 and 6 made of Si crystal.
The mask substrates 502 and 602 having No. 01 and the support frames 503 and 603 supporting the mask substrates 502 and 602 are bonded to each other. Two to three positioning pins 504 indicated by broken lines
The X-ray mask 402 comes into contact with 604 by its own weight and is positioned at a predetermined position of an X-ray exposure apparatus (not shown).

On the other hand, in order to position this X-ray lithography as the next-generation lithography, it is necessary to practically break through some of the problematic technologies industrially. Among them, small industrial SOR
Many developments have been made in the ring both in Japan and overseas, but the X-ray mask, which is another key technology, is aimed at a stable supply, but the current situation is that it has not yet achieved sufficient results. 2. Description of the Related Art Conventionally, an electron beam (EB) exposure method is often used for patterning because pattern line width and positioning accuracy have been required to be extremely high in manufacturing an X-ray mask. In this electron beam (EB) exposure method, mask fabrication (patterning) is performed while positioning and holding the X-ray mask in a horizontal state. In this method,
It has the following features.

(1) Although the depth of focus becomes shallower as the wavelength of the light source becomes shorter, the flatness of the pattern surface of the X-ray mask substrate is so high that it does not cause any particular problem. Since the wafer is subjected to step-and-repeat exposure, the entire surface of the wafer does not necessarily have high flatness, so that stable resolution cannot be obtained.

(2) Since the circuit pattern can be transferred by one exposure, no alignment device is required.

[0009]

However, the above-mentioned conventional example has the following problems.

(1) As shown in FIG. 6, in an X-ray exposure apparatus using synchrotron radiation, an X-ray mask and a wafer are positioned and held in a substantially vertical state for exposure. On the other hand, this X-ray mask is as described above.
In an electron beam exposure apparatus, mask production (patterning) is performed while positioning and holding in a horizontal state. As described above, since the mounting postures (chucking state) at the time of X-ray exposure and the patterning at the time of patterning are different from each other due to the configuration of the exposure apparatus, distortion due to self-weight deformation of the X-ray mask, which does not pose a problem at the time of patterning, causes a problem at the time of X-ray exposure. It has become. That is, in the exposure area, the positional accuracy differs in the vertical direction and the horizontal direction.

(2) Patterning by an electron beam (EB) exposure apparatus has a problem of proximity effect correction due to electron beam scattering and charge-up. In addition, since the thermal distortion due to the local temperature rise adversely affects the pattern accuracy at the drawing start time and the drawing end time, different pattern accuracy is provided in one mask.

The above-mentioned two points are the main problems to be solved by the present invention. As a conventional important problem concerning the manufacture of X-ray masks, a manufacturing technique for mass production which has sufficient resolution and can withstand industrial production. Also needs to be resolved.

That is, the present invention has been made in view of the above-mentioned problems, and the position accuracy and pattern accuracy of the X-ray mask are improved, and the mask has a sufficient resolving power and can withstand industrial production and can be mass-produced. An object is to provide a manufacturing apparatus.

[0014]

The present invention for achieving the above object comprises a master reticle having a line width accuracy N times the minimum pattern size, a master reticle stage on which the master reticle is mounted, and 1 / N. A master mask, a working mask stage on which the working mask is mounted, and an optical system which is provided between the master reticle stage and the working mask stage and reduces to 1 / N. Exposure is performed while scanning the reticle stage and the working mask stage.

Further, the loading condition applied to the working mask at the time of patterning the working mask is made substantially the same as the loading condition at the time of exposure by an X-ray exposure apparatus using synchrotron radiation as a light source.

Still another aspect of the present invention is an X-ray mask produced by scanning exposure using the X-ray mask producing apparatus of the present invention.

In still another invention, a master reticle N times as large as the minimum pattern size produced by an electron beam drawing apparatus is produced, and 1 / N is obtained by scanning exposure using the X-ray mask producing apparatus of the present invention. Of the X-ray mask of the present invention,
This X-ray mask uses synchrotron radiation as a light source X
It is a method of manufacturing a semiconductor device manufactured in a transfer process using a line exposure apparatus.

[0018]

In the present invention configured as described above, exposure is performed while scanning the master reticle stage on which the master reticle is mounted and the working mask stage on which the working mask is mounted. Does not occur and a highly accurate circuit pattern is transferred to the working mask, and the pattern accuracy of the X-ray mask is improved.

Further, the position of the X-ray mask is set by making the load condition applied to the working mask at the time of manufacturing the X-ray mask almost the same as the load condition at the time of exposure by the X-ray exposure apparatus using the synchrotron radiation as a light source. Accuracy is improved.

As a result of these, it becomes possible to manufacture a highly accurate X-ray mask.

[0021]

Embodiments of the present invention will now be described with reference to the drawings.

(First Embodiment) FIG. 1 shows a method of manufacturing an X-ray mask by a reduction mirror projection scan type photolithography apparatus, which best represents the features of the first embodiment of the mask manufacturing apparatus of the present invention. That is, FIG. 1 shows an outline of an X-ray mask manufacturing apparatus that realizes a large-area exposure field by scan exposure using a reduction mirror optical system with little chromatic aberration.

As shown in FIG. 1, the master reticle 1
Has a line width accuracy N times as large as the minimum pattern size drawn by an electron beam (EB) exposure apparatus or the like, and the master reticle 1 has a plurality of positioning pins 3a, 3b, 3c on the reticle stage 2. While contacting, it is adsorbed and held in a vertical state by a reticle chuck (not shown). It is a uniaxial stage that can move in the direction of arrow A of the reticle stage 2 that mounts this reticle chuck. On the other hand, like the master reticle 1, the working mask 4 (X-ray mask) is also held in a vertical state by a working mask chuck (not shown) while being in contact with a positioning pin (not shown). The stage 6 is also a uniaxial stage that can move in the same direction as the reticle stage 2 (direction of arrow B). The working mask stage 6 is configured to have the same moving direction as the moving direction of the image of the master reticle 1 formed by the optical system, has a large stroke in the scanning direction, and has a large stroke in the scanning direction. And a tilt direction moving mechanism having a small stroke in a right angle direction. The working mask 4 is an X-ray mask used in an X-ray exposure apparatus.

Regarding the structure of the catadioptric system provided between the working mask stage 6 and the reticle stage 2, the bending mirror 7 bends the exposure light passing through the master reticle 1 by 90 degrees, and the bending mirror 7 is placed downstream of the bending mirror. The lens group 8, the beam splitter 9, and the concave reflecting mirror 10 are sequentially provided. Reference numeral 11 is a lens group provided between the beam splitter 9 and the working mask stage 6.

In the mask manufacturing apparatus having the above structure,
The reticle stage 2 and the working mask stage 6 are brought to a 4: 1 ratio through a catadioptric system which is reduced to 4: 1.
A highly accurate circuit pattern is transferred to the working mask 4 by performing exposure while scanning at a ratio of.

In this embodiment, the X-ray mask is manufactured by changing the mounting posture during the production of the X-ray mask from horizontal to vertical and by using the same X-ray mask positioning method as that of the X-ray exposure apparatus. Since the load conditions applied to the X-ray mask are the same during the fabrication of the mask and the exposure (see FIG. 6), highly accurate mask fabrication and highly reproducible lithography that equalizes the strain due to its own weight become possible.

(Second Embodiment) FIG. 2 shows a method for manufacturing an X-ray mask by a reduction projection scan type optical exposure apparatus which is a second embodiment of the mask manufacturing apparatus of the present invention. That is, FIG. 2 shows an outline of an X-ray mask manufacturing apparatus that realizes a large-area exposure field by scan exposure by using a reduction projection optical system in an exposure area of a slit image with little image distortion. In the figure, the description of the same parts as those in FIG. 1 is omitted.

As shown in FIG. 2, a reduction projection lens 12 as an optical system having a high NA is provided between the master reticle 1 and the working mask 4. The working mask 4 is a working mask stage 6
It is adsorbed and held while being in contact with the upper three positioning pins 3a, 3b, 3c. Working mask stage 6
Is a uniaxial stage capable of scanning in the same direction as the reticle stage 2, and the arrow C
As shown by, it has a mechanism capable of rotating the entire stage by 90 °. Reference numeral 14 conveys the working mask 4,
It is a hand that can be positioned with respect to the working mask stage 6.

With the above structure, the working mask 4 is transferred by the hand 14 to the working mask stage 6 indicated by the chain double-dashed line in a substantially vertical state. Since the working mask 4 is sucked and held in this state, the vertical strain due to its own weight is held even after it is rotated by 90 ° to the exposure device after passing and becomes horizontal. After positioning the master reticle 1, as in the first embodiment, scanning exposure is performed while controlling the speeds of the reticle stage 2 and the working mask stage 6 in accordance with the reduction ratio of the reduction projection lens 12, thereby achieving high accuracy. Different circuit patterns are transferred to the working mask 4.

In the present embodiment, the patterning by scan exposure is performed in the first embodiment because the working mask serving as the X-ray mask is positioned and sucked and held in a substantially vertical state even when the working mask is mounted in a horizontal state. Similar to the example, the load conditions applied to the X-ray mask are the same during the production of the X-ray mask and during the exposure (see FIG. 6).

(Third Embodiment) FIG. 3 shows a method of manufacturing an X-ray mask by a reduction projection scan type optical exposure apparatus, which is a characteristic of the third embodiment of the present invention. The method of exposing with a slit image is as described in the second embodiment. Also in this figure, description of the same components as those described above with reference to FIGS. 1 and 2 will be omitted.

As shown in FIG. 3, the working mask 4 is a circular mask as shown in FIG. 8. The working mask 4 has two positioning pins 3 (one positioning) on the stage 6 for working mask. The pins are held by suction on the working mask stage 6 while contacting the pins (not shown). In this embodiment, the working mask 4 in the exposure apparatus is mounted in a horizontal position, and the transfer to the exposure position is also horizontal. By the way, as another method of reproducing the self-weight deformation of the X-ray mask in the vertical state in the horizontal state, in this embodiment, the working mask 4 is newly provided with a mechanism for applying an external force corresponding to its own weight. Is. That is, the pressing member 17 presses two points on the outer peripheral portion of the support frame of the working mask 4. The pressing member 17 is provided with two elastic hinge portions, and strain gauges 5a and 5b are attached thereto. The outputs from the strain gauges 5a and 5b are compared and calculated by the control circuit 15, and the control circuit 15 controls the air cylinder 16 to apply an external force corresponding to its own weight to the working mask 4. A voice coil motor may be used as an actuator replacing the air cylinder 16.

In this embodiment, it is possible to manufacture an X-ray mask by transferring a circuit pattern with high accuracy. However, even when the X-ray mask inspection is performed by an electron beam measuring device or the like, a similar external force is applied. Can be done in different forms.

Next, a device manufacturing method in which the X-ray mask described above is applied to an X-ray exposure apparatus will be described.

FIG. 4 shows a manufacturing flow of a reduction device (semiconductor chip such as IC or LSI, liquid crystal panel, CCD, thin film magnetic head, micromachine, etc.). Step S1
In (Circuit design), the circuit of the semiconductor device is designed. In step S2 (mask manufacturing), a mask having the designed circuit pattern is manufactured. On the other hand, in step S3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step S4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by the lithography technique using the mask and the wafer prepared above. Next, step S5 (assembly) is called a post-process, which is a process of forming a semiconductor chip using the wafer manufactured in step S4, and an assembly process (dicing,
Bonding), packaging process (chip encapsulation), etc. are included. In step S6 (inspection), step S5
Inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in 1. are performed. Through these steps, the semiconductor device is completed and shipped (step S7).

FIG. 5 shows a detailed flow of the wafer process. In step S11 (oxidation), the surface of the wafer is oxidized. In step S12 (CVD), an insulating film is formed on the wafer surface. In step S13 (electrode formation), electrodes are formed on the wafer by vapor deposition. Step S14
In (ion implantation), ions are implanted in the wafer. In step S15 (resist process), a photosensitive agent is applied to the wafer. In step S16 (exposure), the circuit pattern of the X-ray mask described above is transferred onto the wafer by the X-ray exposure apparatus. In step S17 (development), the exposed wafer is developed. In step S18 (etching), parts other than the developed resist image are scraped off. Step S
In 19 (resist peeling), the unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer. By using the manufacturing method of this embodiment, it is possible to manufacture a highly integrated semiconductor device, which has been difficult to manufacture in the past.

[0037]

As described above, according to the present invention, it is noted that the X-ray mask chucking state (mounting posture) during X-ray exposure is in a substantially vertical state. Whether the chucking state (mounting posture) of the X-ray mask is vertical or horizontal, by making the load condition of the X-ray mask the same as that at the time of the X-ray exposure, manufacturing of the X-ray mask with high position accuracy Will be possible.

By performing exposure while scanning the master reticle stage and the working mask stage, a high-precision circuit pattern is transferred to the working mask without causing thermal distortion due to a local temperature rise, and X-rays are transferred. The pattern accuracy of the mask is improved.

Further, according to the present invention, the X-ray mask manufacturing apparatus adopting the scan exposure system can improve the resolution and enable future large-area exposure field, and realize stable supply of the X-ray mask which can endure mass production.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of an X-ray mask manufacturing apparatus of the present invention.

FIG. 2 is a perspective view of a second embodiment of the X-ray mask manufacturing apparatus of the present invention.

FIG. 3 is a perspective view of a third embodiment of the X-ray mask manufacturing apparatus of the present invention.

FIG. 4 is a manufacturing flow of a semiconductor device.

5 is a detailed flow of the wafer process of FIG.

FIG. 6 is a conceptual diagram of X-ray lithography using synchrotron radiation in the X-ray exposure apparatus.

FIG. 7 is an external view of an X-ray mask.

FIG. 8 is an external view of another X-ray mask.

[Explanation of symbols]

 1 Master Reticle 2 Reticle Stage 3, 3a, 3b, 3c Positioning Pin 4 Working Mask (X-ray Mask) 5a, 5b Strain Gauge 6 Working Mask Stage 7 Bending Mirror 8 Lens Group 9 Beam Splitter 10 Concave Reflector 11 Lens Group 12 Reduction projection lens 13 Indexer 14 Hand 15 Control device 16 Air cylinder 17 Pressing member S1 to S7, S11 to S19 Step

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location 7352-4M 531 S

Claims (4)

[Claims] 1. A master reticle having a line width accuracy N times the minimum pattern size, a master reticle stage on which the master reticle is mounted, a working mask reduced to 1 / N, and a working on which the working mask is mounted. A mask stage, and an optical system provided between the master reticle stage and the working mask stage for reducing to 1 / N, and performing exposure while scanning the master reticle stage and the working mask stage X Line mask making device. 2. The load condition applied to the working mask at the time of patterning the working mask is substantially the same as the load condition at the time of exposure by an X-ray exposure apparatus using synchrotron radiation as a light source. The described X-ray mask manufacturing apparatus. 3. An X-ray mask manufactured by scanning exposure using the X-ray mask manufacturing apparatus according to claim 1. 4. A master reticle N times as large as a minimum pattern size produced by an electron beam drawing apparatus is produced, and 1 / N is obtained by scanning exposure using the X-ray mask producing apparatus according to claim 1. An X-ray mask according to claim 3 is produced,
This X-ray mask uses synchrotron radiation as a light source X
A method for manufacturing a semiconductor device manufactured by a transfer process using a line exposure apparatus.