JPH06349802A - Precision cleaning device for substrate - Google Patents

Abstract

(57) [Summary] [Purpose] Both organic and inorganic contaminants can be removed in a short time without the need for safety equipment required for the IPA vapor drying method. The purpose is to provide a small-sized precision cleaning device. A substrate precision cleaning apparatus according to the present invention comprises an ultraviolet irradiation means 11 for irradiating the surface of a substrate 14 with ultraviolet rays in a clean air atmosphere to remove foreign matters on the surface, and ice particles or ice particles on the surface of the substrate. An ice scrubbing means 12 for injecting dry ice particles to remove foreign matter on the surface,
The ultraviolet irradiation means and the ice scrub means operate simultaneously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for precisely cleaning a substrate, and more particularly to removing foreign matter (fine dust, stains or oil) attached to a glass substrate such as a reticle or photomask used in a semiconductor manufacturing process. A cleaning device for removing.

[0002]

2. Description of the Related Art If foreign substances such as dust adhered to a glass substrate such as a reticle or a photomask are left as they are, these foreign substances are transferred onto the wafer and cause defects in the manufactured wafer. Since various kinds of contaminants adhere to the substrate, various cleaning methods have been proposed according to the kind of adhered contaminants.

For example, an ultraviolet irradiation method is known as a method for removing organic contaminants such as fats and oils (see, for example, Japanese Patent Laid-Open No. 3-101223). According to this method, the surface of the substrate is irradiated with ultraviolet rays in a clean air atmosphere. Due to the action of light energy of ultraviolet rays, clean air is converted into ozone (O ₃ ) and active oxygen atoms (O ^* ). The generated active oxygen atoms react with the organic substance on the substrate, and the chemical action can remove the organic substance-based foreign matter adhering to the substrate surface.

On the other hand, as a method for removing inorganic contaminants such as metal oxides and dust, a brush scrubbing method using a pair of rotating brushes and an ice scrubbing method in which clean ice particles are sprayed onto the substrate surface under pressure (for example, a special method). Kaihei No. 3-1683
2). In either method, in principle, contaminants on the substrate surface are directly removed by physical action.

As described above, the ultraviolet irradiation method is effective for organic contaminants, and the brush scrub method and ice scrub method are effective for inorganic contaminants. In general, both organic substances and inorganic substances adhere to the surface of the substrate as contaminants, so that a plurality of cleaning devices for carrying out various cleaning methods have been used intermittently. That is, the substrate is cleaned by sequentially using a plurality of cleaning devices individually. However, in the conventional method in which a plurality of cleaning apparatuses are sequentially used in this way, since the work of transporting the substrate is added between each cleaning apparatus, foreign substances may adhere during transportation, and the substrate that has already been cleaned may be removed. It was difficult to maintain the cleanliness of the surface. In addition, it is not preferable from the viewpoints of work efficiency and work time.

Therefore, there has been proposed a cleaning device in which the above-described plurality of cleaning devices are incorporated in one chamber. FIG. 4 is a diagram schematically showing the configuration of the proposed cleaning device. The illustrated cleaning device includes a chamber 6 that is maintained in a clean atmosphere. In the cleaning chamber 6, an ultraviolet treatment tank 2, a brush scrubbing tank 3, an ultrasonic cleaning tank 4 and an IP
A steam drying tank 5 is provided individually. The substrate 1 carried into the cleaning chamber 6 by an appropriate transfer means is sequentially cleaned in each processing tank in the cleaning chamber 6 in which a clean atmosphere is maintained.

In the illustrated apparatus combination, the ultrasonic cleaning step is not an essential constituent element and can be omitted if necessary. However, in the scrubbing process using the brush scrubbing method or the ice scrubbing method, the surface of the substrate after cleaning is in a wet state, and thus a drying process is essential. As a drying method, IPA (isopropyl alcohol) vapor drying as illustrated is widely used.

[0008]

In the conventional substrate cleaning apparatus as described above, various cleaning methods are applied individually and sequentially, and the substrate cleaning can be performed in a short time. There was an inconvenience that the throughput was low. Further, since it is necessary to individually accommodate a plurality of processing tanks for carrying out various cleaning methods, there is a disadvantage that the apparatus becomes large and the occupied space becomes large. Furthermore, when the IPA vapor drying method is used for the drying process of the substrate, there is a disadvantage that the safety equipment required because IPA is a combustible substance becomes large-scale, and thus the apparatus becomes large-scale. . Further, since the cleaning using photochemistry by the ultraviolet irradiation method and the cleaning by physical action by the scrub method are separately performed, the cleaning effect beyond the individual cleaning ability cannot be obtained.

The present invention has been made in view of the above-mentioned problems, and can remove organic contaminants and inorganic contaminants with high cleaning ability in a short time, and thus IPA can be removed. An object of the present invention is to provide a small-sized precision cleaning device that does not require the safety equipment required for the steam drying method.

[0010]

In order to solve the above-mentioned problems, in the present invention, ultraviolet irradiation means for irradiating the surface of a substrate with ultraviolet rays in a clean air atmosphere to remove foreign matters on the surface, An ice scrub means for ejecting ice particles or dry ice particles onto the surface of the substrate to remove foreign matter on the surface is provided, and the ultraviolet irradiation means and the ice scrub means operate simultaneously on the same substrate. A substrate precision cleaning device is provided.

According to a preferred aspect, the ultraviolet irradiation means continues to operate for a predetermined period even after the ice scrub means has stopped operating. Further, according to a further preferable aspect, an ionized gas spraying unit for spraying the ionized gas onto the surface of the substrate is provided.

[0012]

In the substrate precision cleaning apparatus of the present invention, the ultraviolet irradiation means and the ice scrubbing means can be operated simultaneously on the same substrate. Therefore, since the conventional work of transferring the substrate between the cleaning treatment tanks is eliminated, the cleaning efficiency is significantly improved. Further, since the sequential and intermittent processing work of each conventional cleaning process is replaced by a continuous and single cleaning process, the cleaning process time is significantly shortened. In addition,
In this specification, an ice scrub method for ejecting ice particles onto a surface of a substrate to remove foreign matters and a dry ice scrub method for ejecting dry ice particles to remove foreign matters are collectively referred to as “ice scrub” method. .

On the other hand, from the viewpoint of the chemical action of the present invention on the substrate surface, even if the inorganic contaminants are too strong to be removed by the ordinary scrubbing treatment, The combined use of the ultraviolet irradiation according to the present invention and ice scrubbing enables removal. That is, the bonds of the atoms forming the inorganic contaminants are broken by the action of the light energy of the irradiated ultraviolet rays, but the broken interatomic bonds are recombined when it takes time until the next scrubbing process as in the conventional case. . However, in the present invention, the atomic force can be cut by the ultraviolet irradiation method and at the same time the physical force of scrubbing can be applied to the surface of the substrate, so that it is possible to reliably remove the inorganic contaminants having a strong adhesive force. In other words, the synergistic effect of the chemical action of UV energy and the physical action of ice scrub can be utilized.

Further, according to a preferred aspect of the present invention, the operation of the ultraviolet irradiation means can be continued for a predetermined period even after the operation of the ice scrub means is stopped. Therefore,
In the cleaning process, the substrate surface is dried only by stopping the ice scrubbing means prior to the ultraviolet irradiation means, and it is not necessary to provide a special drying tank such as the conventional IPA vapor drying tank, and the safety equipment is also provided. Need not be attached.

Furthermore, according to a preferred aspect of the present invention, ionized clean air can be blown onto the surface of the substrate. Therefore, it is possible to prevent the substrate from being charged during the cleaning process. In this way, it is possible to prevent the inorganic contaminants physically removed from the substrate surface during the scrubbing process from reattaching to the substrate surface due to the action of static electricity. Furthermore, by spraying ionized clean air onto the surface of the substrate even in the drying process by ultraviolet irradiation, the possibility that foreign substances will adhere from the atmosphere during the substrate transfer process after the cleaning process is minimized and formed on the substrate. It is possible to prevent electrostatic destruction of the formed pattern.

[0016]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically illustrating the configuration of a substrate precision cleaning apparatus according to an embodiment of the present invention. Also, FIG.
FIG. 3 is a view of a cross section taken along line II-II of the device of FIG. 1 as seen from the direction III (Z direction) of FIG. The apparatus of FIG. 1 includes a cleaning chamber 7 provided with an opening / closing shutter 8 slidable in the X direction by a drive unit (not shown) and a clean air supply port 9. A substrate 14 to be cleaned is supported in the cleaning chamber 7 by a supporting means 17 (see FIG. 3) so that its surface is substantially parallel to the YZ plane. Board 1
A pair of lamps 11 (11A, 11B) for irradiating ultraviolet rays are arranged so as to face the surface of No. 4. As shown in FIG. 1, each ultraviolet lamp 11 has a rectangular shape slightly larger than the substrate 14 as a whole, and is positioned so that the irradiation surface thereof is substantially parallel to the surface of the substrate 14 facing the irradiation surface.

The apparatus of FIG. 1 further includes eight ice particle jet nozzles 12 arranged on both sides of the surface of the substrate 14. Each ice particle injection nozzle 12 is connected to a device (not shown) that pressurizes and feeds ice particles formed by solidifying pure water. The device for feeding ice particles under pressure has a mixing portion for making water into small water droplets by the action of N ₂ and a chamber for ice particles, and the water droplets from the mixing portion are fed under pressure and enter the ice particle chamber. Then, the water droplets become ice particles in the chiller (cooler), and the ice particles are ejected from the nozzle under the pressure of N ₂ . The pressure-fed ice particles are ejected toward the surface of the substrate 14 in a conical shape through the ice particle ejection nozzle 12, as shown in FIG. Each ice particle injection nozzle 12 has two nozzles 12a arranged at positions corresponding to the upper two corners of the ultraviolet lamp 11A and two nozzles 12a arranged at positions corresponding to the lower two corners of the ultraviolet lamp 11A. Four nozzles including a nozzle 12b, two nozzles 12a arranged at positions corresponding to the upper two corners of the ultraviolet lamp 11B and a position corresponding to two lower corners of the ultraviolet lamp 11B. It has four nozzles consisting of two nozzles 12b. With the total of eight ice particle injection nozzles 12, the substrate 1
It is positioned so that it can be sprayed with ice particles over the entire surface of 4.

A pair of ionized air outlets 13 are arranged so as to face the side end faces of the substrate 14 (the faces substantially perpendicular to the YZ plane).
Is provided. Each ionized air outlet 13 is connected to a device (not shown) that ionizes clean air and supplies it to the substrate 14. The ionized air outlet 13 has an X
Has a longitudinal direction. Ionized air is supplied from the outlet 13 to the substrate 14 by an ionized air feeder (not shown).
Will be supplied to. At this time, in order to blow the ionized air sufficiently and uniformly, the blowout port 13 in FIG.
Is sufficiently larger than the substrate 14 when viewed in the ZX plane. The ionized air that has been sent out flows out substantially parallel to the substrate 14 (YZ plane) via the outlet 13 and acts on the surface thereof. Although FIG. 2 shows the two outlets 13 arranged side by side in the Y direction, the number of outlets 13 may be one. The cleaning chamber 7 is further provided with an exhaust port 10 for discharging the air in the chamber and a drain port 15 for discharging the liquid generated in the chamber in the lower region of the cleaning chamber 7.

FIG. 3 schematically shows the structure of the substrate supporting means and the conveying means. The transfer means shown in FIG.
An arm 16 is provided for gripping or pinching the upper side surface portion of No. 4 from both sides. The arm 16 is movable in the Y direction by a driving unit (not shown), and can reciprocate between the cleaning chamber 7 and a substrate cassette that stores a substrate to be cleaned. Further, the supporting means 17 for supporting the substrate 14 at a predetermined position in the cleaning chamber 7 is provided with a groove for receiving the substrate 14 from the transfer means, and in the groove, the lower end surface of the substrate 14 and It is designed to support the lower side surface. Support means 17
Is configured to be able to reciprocate in the vertical direction (Z direction) by an appropriate drive means (not shown).

The operation of the apparatus of this embodiment will be described below with reference to FIGS. For example, the reticle substrate 14 stored in the reticle cassette (not shown) is moved to the arm 16
It is conveyed to the cleaning chamber 7 while being gripped by. Next, the opening / closing shutter 8 of the cleaning chamber 7 is opened, and the substrate 14 is loaded into the cleaning chamber 7. On the other hand, in the cleaning chamber 7, the supporting means 17 is raised to a predetermined position for receiving the substrate 14. When the arm 16 is sufficiently close to the support means 17, the substrate 14 being gripped is released, and the substrate 14 is released.
Is placed in the groove of the supporting means 17. The supporting means 17 having received the substrate 14 descends to a predetermined position for the cleaning process, that is, a position where each surface of the substrate 14 faces the ultraviolet lamp 11. Thus, the surface of the substrate 14 is supported substantially parallel to the vertical direction.

The arm 16 having released the substrate 14 retracts to the outside of the cleaning chamber 7, and the opening / closing shutter 8 is closed. When the opening / closing shutter 8 is closed, clean air is supplied into the cleaning chamber 7 through the clean air supply port 9 and exhausted through the exhaust port 10 to form a clean air atmosphere in the cleaning chamber 7. . Next, a pair of ultraviolet lamps 1
1 is operated to irradiate the surface of the substrate 14 with ultraviolet rays, and at the same time, ice particles are conically ejected toward the surface of the substrate 14 via eight ice particle ejection nozzles 12 which are appropriately arranged.

When the surface of the substrate 14 is irradiated with ultraviolet rays in a clean air atmosphere by the pair of ultraviolet lamps 11,
Due to the action of light energy of ultraviolet rays, clean air is converted into ozone (O ₃ ) and active oxygen atoms (O ^* ). The generated active oxygen atoms react with the organic substance on the substrate, and the chemical action can remove the organic substance-based foreign matter adhering to the substrate surface. On the other hand, the ice particles ejected in a conical shape through the ice particle ejecting nozzle 12 act on the entire surface of the substrate 14. By the synergistic action of the physical action of the ice particles colliding with the surface of the substrate 14 and the chemical action of the energy of the irradiation ultraviolet light (cutting the bond of the inorganic atom), the inorganic foreign matter adhering to the substrate surface is surely removed. be able to.

The foreign matter removed by the ice scrubbing is discharged through the drainage port 15 provided in the lower portion of the cleaning chamber 7 together with the water in which the ice particles that have collided with the surface of the substrate 14 are melted. In this way, the surface of the substrate 14 becomes wet by ice scrubbing. Board 14
Since it is supported in the vertical direction, it is possible to prevent water droplets from accumulating on the surface, but a forced drying step is required. Therefore, it is preferable to stop the ice scrubbing and continue the ultraviolet irradiation for a certain time while keeping the clean air atmosphere to dry the substrate 14.

Further, the ionized clean air is supplied into the cleaning chamber 7 through the ionized air outlet 13 to supply the substrate 14
It is preferable to act on the surface of. The ionized clean air is clean air containing positively and negatively charged ions, and has the action of removing static electricity on the surface of the substrate 14 and preventing static charge. The ionized clean air may be supplied only during the cleaning step by scrubbing, but it is more preferable to continue to achieve sufficient static elimination during the drying step by ultraviolet irradiation. This is because if the supply of ionized air is stopped immediately after the ice scrub ends, it may be considered that the static electricity is not completely removed. Therefore, it is preferable to continue the supply of ionized air also in the subsequent drying step.

Substrate 1 which has been cleaned and dried
Since No. 4 is carried out of the cleaning chamber 7 according to a procedure almost reverse to the procedure for carrying in the substrate, detailed description thereof will be omitted. The above steps are repeated for the next substrate to be cleaned. In the present embodiment, the present invention has been described by taking the scrubbing process of spraying ice particles as an example, but it is clear that the same effect can be obtained even if the scrubbing process of spraying dry ice particles is adopted. .
In this case, since the dry ice particles are melted and immediately vaporized, the drying step is omitted, and there is an advantage that stains caused by water droplets hardly remain on the substrate surface.

Further, in this embodiment, the substrate is supported in the vertical direction, but supporting it in the horizontal direction does not impair the basic operation and effect of the present invention. Furthermore, in this embodiment, the ice particles sprayed through the spray nozzle are configured to act on the entire surface of the substrate, but the supported substrate is appropriately moved in the vertical direction and / or the horizontal direction. The injection may be performed while appropriately moving. In this case, it becomes possible to reduce the required number of ice particle injection nozzles.

[0027]

As described above, in the substrate precision cleaning apparatus of the present invention, the ultraviolet irradiation means for irradiating the surface of the substrate with ultraviolet rays in a clean air atmosphere to remove foreign matters on the surface, and the surface of the substrate And ice scrub means for ejecting ice particles or dry ice particles to remove foreign matter on the surface, and the ultraviolet irradiation means and the ice scrub means operate simultaneously on the same substrate. Therefore, the cleaning efficiency is significantly improved and the cleaning processing time is significantly shortened. Also, because the synergistic effect of the chemical action of ultraviolet energy and the physical action of ice scrub can be used,
Inorganic contaminants with strong adhesiveness can be reliably removed.

[Brief description of drawings]

FIG. 1 is a diagram schematically illustrating a configuration of a substrate precision cleaning apparatus according to an embodiment of the present invention.

2 is a cross-sectional view of the device of FIG. 1 along line II-II.

FIG. 3 is a diagram schematically showing a configuration of a substrate supporting means and a conveying means.

FIG. 4 is a diagram schematically illustrating a configuration of a conventional substrate cleaning apparatus.

[Explanation of symbols]

 7 Cleaning Chamber 8 Opening / Closing Shutter 9 Clean Air Supply Port 10 Exhaust Port 11 Ultraviolet Lamp 12 Ice Particle Jetting Port 13 Ionized Air Blowing Port 14 Substrate 15 Drainage Port 16 Arm 17 Supporting Means

Claims (9)

[Claims] 1. An ultraviolet irradiation means for irradiating the surface of a substrate with ultraviolet rays in a clean air atmosphere to remove foreign matters on the surface, and ice particles or dry ice particles for injecting ice particles or dry ice particles onto the surface of the substrate. And a scrubbing means for removing foreign matter, wherein the ultraviolet irradiation means and the ice scrubbing means operate simultaneously on the same substrate. 2. The ultraviolet irradiation means is provided so as to face the surface of the substrate and a clean air supply means for supplying the clean air into the chamber in which the substrate is housed to form the clean air atmosphere. The apparatus according to claim 1, wherein the apparatus comprises a pair of ultraviolet irradiation lamps. 3. The ice scrubbing means comprises a plurality of spray nozzles for spraying the ice particles or the dry ice particles in a conical shape, and the plurality of spray nozzles act over the entire surface of the substrate. Device according to claim 1 or 2, characterized in that it is positioned as follows. 4. The ice scrubbing means comprises a plurality of injection nozzles for pressurizing and spraying the ice particles or the dry ice particles in a conical shape, and the plurality of injection nozzles act on the entire surface of the substrate. The apparatus according to claim 1 or 2, further comprising a substrate supporting means for moving the substrate. 5. The apparatus according to claim 1, wherein the ultraviolet irradiation means continues to operate for a predetermined period even after the ice scrubbing means stops operating. 6. The apparatus according to claim 1, further comprising ionized gas spraying means for spraying the ionized gas onto the surface of the substrate. 7. The apparatus according to claim 6, wherein the gas is clean air. 8. A device according to claim 6 or 7, wherein the spraying means operates synchronously with the ice scrubbing means. 9. The apparatus according to claim 6, wherein the spraying unit operates in synchronization with the ultraviolet irradiation unit.