KR20030013708A - Substrate cleaning system - Google Patents

Abstract

PURPOSE: A system for cleaning a substrate is provided to effectively clean the substrate by eliminating a problem caused by a brush scrubber or an ice scrubber that may contaminate the substrate or break down a device. CONSTITUTION: An ice particle fabricating apparatus(2) fabricates ice particles(1b) by using water as a raw material. A cleaning slurry fabricating apparatus(5) mixes the ice particles with a cleaning solution(3) that has a solidifying point lower than that of water and is kept as a temperature lower than that of the solidifying point of water, so that cleaning slurry(4) is fabricated. The substrate(6) is maintained in a cleaning process chamber(7). A cleaning slurry injecting apparatus(9) injects the cleaning slurry to the substrate maintained in the process chamber so that the injected cleaning slurry collides against the substrate.

Description

Substrate cleaning system {SUBSTRATE CLEANING SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate cleaning system for cleaning substrates such as semiconductor wafers, electronic device substrates, liquid crystal substrates, photomasks, and glass substrates, and removing particles (fine particles serving as substrate contamination sources) attached thereto.

Substrate cleaning, such as semiconductor wafers, is generally performed by a brush scrubber that removes particles adhering to the substrate by wiping the surface of the substrate with a brush made of 100 to 300 µm diameter mohair (angora chlorine), nylon, or the like. . However, in the cleaning of the substrate by such a brush scrubber, the substrate is adhered to the surface of the substrate while the brush is rotated, and the foreign matter is wiped off by the frictional force. Therefore, the substrate contamination source is caused by the collision between the brushes and the step of the substrate wiring. Particles, which become fine particles, are generated and reattached to the substrate, thereby reducing the cleaning effect of the substrate.

In recent years, an ice scrubber has been proposed in which fine ice particles are sprayed and collided with a substrate by a carrier gas to clean the substrate. According to such an ice scrubber, since a board | substrate is wash | cleaned, a board | substrate washing | cleaning can be performed effectively, without particle | grains generate | occur | producing and reattaching.

However, in substrate scrubbing with an ice scrubber, ice particles are caused to rush at high speed to the substrate by gas (carrier gas), which may cause damage to the substrate. In addition, ice particles after colliding with the substrate are scattered, and the removed particles are blown around the substrate and the substrate may be recontaminated. In order to prevent these particles from blowing up, it is necessary to rinse the substrate with pure water or the like with the injection of ice particles. The problem arises.

An object of the present invention is to provide a substrate cleaning system which can clean a substrate well and effectively without causing a problem caused by such an ice scrubber.

1 is a system diagram showing an embodiment of a substrate cleaning system according to the present invention.

(Explanation of the sign)

1: Raw material water (pure water) 1a: Spray particle (fine grain)

1b: Copper Freezing (Ice Particles) 2: Copper Freezing Manufacturing Equipment

3: cleaning solution 4: cleaning slurry

5: cleaning slurry manufacturing apparatus 6: substrate

7: Cleaning process room 8: Carrier gas

9: Slurry spraying device for cleaning 10: Copper granulation container

11: Raw water supply mechanism 21: Cleaning liquid storage container

22: Refrigerator (cooling mechanism) 23: Mixed stirring mechanism

24: bubbling gas 34: injection gun

In order to achieve the above object, the present invention, in particular, the freezing granulation device for producing fine freezing granules with water as a raw material, and the freezing granules produced by the freeze granulation production device as a liquid having a lower freezing point than water as a lower temperature than the freezing point of water A cleaning slurry production apparatus for mixing the cleaning liquid held by the production of the cleaning slurry to produce the cleaning slurry, a cleaning processing chamber for holding the substrate, and a cleaning slurry prepared by the cleaning slurry production apparatus with a carrier gas to be retained in the cleaning processing chamber. It is proposed a substrate cleaning system comprising a cleaning slurry spraying device for spraying and colliding toward a formed substrate.

In such a substrate cleaning system, pure water or the like is used as a raw material (raw material water) of the frozen granules. As the cleaning liquid, it is preferable to use a liquid which does not adversely affect the substrate. For example, it is preferable to use isopropyl alcohol, methyl alcohol, ethyl alcohol, acetone, or a mixture of any of these and water. It is preferable to use isopropyl alcohol or a mixture of ethyl alcohol and water. Moreover, it is preferable that content of the freeze granules in a washing | cleaning slurry is 1-20 wt (washing liquid: 99-80 wt%).

In a preferred embodiment, the freeze granulation production apparatus includes a freeze granulation production vessel whose interior is kept at a cold air atmosphere and a raw material water supply mechanism for supplying the raw water as fine granules in this container, and having 1 to 150 µm. It is configured to produce a spherical freeze granule of. In addition, the cleaning slurry production apparatus is connected to the freezing granulation vessel, and the storage liquid storage vessel in which the freezing grain is dropped from the freezing granulation vessel, and the cooling mechanism for cooling and keeping the cleaning liquid in the vessel at -5 to -40 ° C. And a mixing and stirring mechanism for mixing and stirring the cleaning liquid and the freezing granules in the cleaning liquid storage container to uniformly disperse the freezing granules in the cleaning liquid. In addition, it is preferable that a cleaning residual water mechanism for recovering the cleaning slurry used for cleaning the substrate from the cleaning processing chamber to the cleaning slurry manufacturing apparatus (for example, the cleaning solution storage container) is provided so as to reuse the frozen granules or the cleaning solution. Do.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described concretely based on FIG.

As shown in Fig. 1, the substrate cleaning system according to the present invention includes a freeze granulation manufacturing apparatus 2 for producing fine freeze granules 1b using water 1 as a raw material, and a freeze granules 1b. To a cleaning slurry production apparatus 5 for mixing the cleaning liquid 3 with the cleaning liquid 3 to produce the cleaning slurry 4, a cleaning processing chamber 7 for holding a substrate 6 such as a semiconductor wafer to be cleaned, The slurry 4 spraying apparatus 9 which sprays and collides the slurry 4 toward the board | substrate 6 hold | maintained in the washing process chamber 7 by the carrier gas 8 is provided.

The freeze granulation production apparatus (2) uses a cryolip production vessel (10), which is a hermetic sealed container kept in a cold air atmosphere, and the raw water (1) (for example, pure water) in the container (10) as fine granules (1a). The raw material water supply mechanism 11 to supply is provided. In the container 10, a coolant such as liquid nitrogen or a coolant gas 13 is ejected from the spray nozzle 12 provided above the circumferential wall, thereby lowering the freezing point of the water 1 (for example, about -80 ° C). ) Is maintained in the cold atmosphere. The raw material water supply mechanism 11 includes a spray nozzle 14 installed at the ceiling of the container 10, a sealed raw material water tank 15 for storing the raw water 1, and a liquid portion of the raw water tank 15. And a gas supply pipe (18) connected to the spray nozzle (14) and a gas supply pipe (18) from the gas tank (17) to the gas phase of the raw water tank (15). The pressurized gas 18a is supplied to pressurize the inside of the raw water tank 15 to pressurize and feed the raw water 1 from the raw water supply pipe 16 to the spray nozzle 14, and to finely feed the raw water 1. As 1a, it is comprised so that the container 10 may be sprayed.

The fine grains 1a sprayed from the spray nozzles 14 are immediately frozen by heat exchange with the refrigerant 13 in a spherical form by the surface tension, and are frozen granules (ice) 1b having a fine spherical uniform diameter. Is manufactured. This freezing lip 1b is settled inside the container 10 to the bottom wall of an inverted shape, and falls out of the container 10 from the freezing lip extraction tube 19 formed in the center of the bottom wall. In addition, the raw material water supply pipe 16 is provided with a pressure and flow rate regulator 20 so that the spraying pressure from the spray nozzle 14 can be adjusted. Although the diameter of the spray particle 1a, ie, the freezing granule 1b, is determined by the spray pressure and the spray hole diameter of the spray nozzle 14, in general, the spray conditions such as spray pressure have a spherical shape of 1 to 150 mu m. It is preferable to set so that the frozen lip 1b may be obtained. However, although the diameter of the freezing lip 1b is set according to the type of the substrate 6, in general, when the particle size is less than 1 µm, it is difficult to remove large particles. This is because the ability to remove particles by colliding with details decreases.

The cleaning slurry production apparatus 5 cools and insulates the cleaning liquid storage container 21, which is a sealed container located directly under the cryoliptical production container 10, and the cleaning liquid 3 accommodated in the container 21 at a predetermined temperature. Cooling mechanism 22 to be mixed with a mixing and stirring mechanism 23 for uniformly dispersing the freezing granules 1b into the washing liquid 3 by mixing and stirring the cleaning liquid 3 and the freezing granules 1b in the container 21. do.

The cleaning liquid storage container 21 is connected to the freezing granulation container 10 by connecting the lower end of the freezing granules extraction pipe 19 to its ceiling, and the freezing granules 1b made of the cryogenic granulation container 10 are manufactured. ) Is supplied to the cleaning liquid 3 in the cleaning liquid storage container 21 from the freezing lip extraction tube 19, and the cleaning liquid is a mixture of the frozen particles 1b and the cleaning liquid 3 in the container 21. The slurry 4 is prepared. As the cleaning liquid 1b, a liquid having a lower freezing point than the water 1, which is a raw material of the freezing granule 1b, and which does not adversely affect the substrate 6 is used, but in general, alcohols are preferably used. For example, isopropyl alcohol (mp = -89.5 ° C: bp = 82.4 ° C), methyl alcohol (mp = -97.78 ° C; bp = 64.65 ° C), ethyl alcohol (mp = -114.1 ° C; bp = 78.3 ° C), ethyl A mixture of alcohol (95 vol%) and water (bp = 78.2 ° C.), acetone (-94.82 ° C .; bp = 56.5 ° C.), a mixture of acetone (50 vol%) and water (50 vol%), and the like are used.

The cooling mechanism 22 is a refrigerator, and the refrigerator 22 causes the cleaning liquid 3 in the container 21 to be lower than the freezing point of the raw material water 1 and higher than the freezing point of the cleaning liquid 3 (generally, , -5 to -40 deg. C) is cooled and insulated at a predetermined temperature, so that the freezing granules 1b do not dissolve in the container 21 and the solid solution is properly mixed without the washing liquid 3 solidifying. A slurry (washing slurry) 4 is secured. For example, in the case where isopropyl alcohol is used as the cleaning liquid 3, the freezing granules are cooled and kept in the range of -5 to -15 ° C so that the solubility of the freezing granules (ice) 1 is washed. The slurry 4 which does not produce the coagulation | solidification of propyl alcohol) 3 is obtained.

The mixing and stirring mechanism 23 supplies the bubbling gas 24, such as nitrogen gas, into the cleaning liquid 3 or the cleaning slurry 4 in the container 21, thereby purifying the cleaning liquid storage container from the freezing lip extraction tube 19. 21. The freezing lip 1b drop-fed to 21 is rapidly mixed with the washing liquid 3 so as to be uniformly dispersed in the washing liquid 3, that is, a uniform ice concentration at which the freezing grain 1b is uniformly dispersed in the washing liquid 3 It is comprised so that the washing | cleaning slurry 4 may be obtained. The amount of production of the freezing granules 1b by the freezing granulator 2 is applied to the cleaning slurry 4 in the container 21 during the ejection of the cleaning slurry 4 by the cleaning slurry spraying device 9 described later. The frozen lip 1b and the washing | cleaning liquid 3 in it are adjusted so that a fixed compounding ratio may be maintained. Specifically, the cleaning slurry 4 is adjusted to be a mixed liquid of 1 to 20 wt% of the freezing granules 1 b and 99 to 80 wt% of the cleaning liquid 3. However, if the freeze lip 1b is less than 1 wt%, foreign matter adhering to the substrate 6 cannot be sufficiently cleaned and removed. If the freeze lip 1b exceeds 20 wt%, the inside of the pipe of the cleaning slurry spraying device 9 to be described later is This is because damage such as closing them occurs. Moreover, the exhaust port 25 is formed in the upper part (weather part) of the container 21. In addition, both the containers 10 and 21 integrally connected by the freeze lip extraction tube 19 are arranged in the heat insulation region surrounded by the heat insulation wall 26.

The cleaning processing chamber 7 is formed of an inclined surface inclined downwardly to the cleaning residue outlet 27 provided in the cleaning processing chamber. The substrate 6 such as a semiconductor wafer is disposed on the back surface of the cleaning processing chamber 7. The support shaft 28 which supports the center of rotation in a horizontally rotatable manner, the drive source (motor, etc.) 29 which rotates and drives it, and the cleaning slurry 4 used for cleaning the substrate from the cleaning processing chamber 7 In the slurry manufacturing apparatus 5, the washing residue water-retaining mechanism 30 which is collect | recovered is provided. The cleaning slurry used for cleaning the substrate, that is, freeze granules or cleaning liquid (hereinafter referred to as "cleaning residue") 4a flows down the bottom wall 7a of the cleaning processing chamber 7 to the cleaning residue outlet 27, and the outlet It discharges out of the cleaning process chamber 7 from (27). The cleaning residual water mechanism 30 includes a recovery pipe 31 guided from the cleaning residue outlet 27 to the cleaning liquid storage container 21, a recovery pump 32 provided on the recovery pipe 31, and a downstream filter 33 thereof. And a particle contained in the cleaning residue 4a by the filter 33 after the cleaning residue 4a discharged from the cleaning residue outlet 27 is removed from the cleaning residue discharge port 27. 21). That is, the freezing lip 1b to the cleaning liquid 3 (and its cold heat) injected into the cleaning processing chamber 7 from the cleaning slurry spraying device 9 described later are recovered and reused in the cleaning slurry manufacturing apparatus 5. Consists of. Moreover, although not shown in the upstream side of the filter 33 to the pump 32 in the recovery pipe 31, the appropriate heat exchanger for ice-collecting the freezing lip | rip 1b collect | recovered in liquid phase is provided.

The cleaning slurry spraying device 9 is constructed from a pair of upper and lower spray guns 34 and 34 arranged to face each other at a front and rear surface of the substrate 6 in the cleaning processing chamber 7 and the cleaning liquid storage container 21. A slurry supply pipe (35) guided and branched to the injection guns (34, 34) and a slurry supply pipe (35) are installed in the slurry supply pipe (35) through the supply pipe (35) from the cleaning liquid storage container (21) to the injection gun (35). Supply pumps 36 for supplying to the 34 and 34, and the carrier guns 8, such as nitrogen gas, are supplied to the injection guns 34 and 34 from the gas tank 37 to the injection guns 34 and 34. It is provided with a gas supply pipe 38 to supply the cleaning slurry 4 and the carrier gas 8 to the injection guns 34 and 34, thereby accelerating the injection of the cleaning slurry 40 by the carrier gas (8) The guns 34 and 34 are sprayed and collided with the front and back surfaces of the substrate 6. That is, from the guns 34 and 34, solids (freezing particles 1b) and liquids (cleaning liquid 3) , Gas (carrier gas The three-phase mixed fluid of (8) is sprayed on the front and back surfaces of the substrate 6.

According to the substrate cleaning system configured as described above, the cleaning slurry 4, which is a mixed fluid of the freezing lip 1b and the cleaning liquid 3, is accelerated by the carrier gas 8, and is discharged from the injection guns 34, 34. The substrate is cleaned and sprayed on the front and back surfaces of the substrate 6 by a very good and effective process. That is, unlike the case where the freezing lip (ice particles) are accelerated by the carrier gas and collide with the substrate like the ice scrubber described above, the mixed fluid of the freezing lip 1b and the cleaning liquid 3 collides with the substrate 6. The impact applied to the substrate surface due to the collision of the freeze lip 1b is mitigated by the cleaning liquid 3. That is, the liquid (cleaning liquid 3) which is high in viscosity compared with gas (carrier gas) functions as a liquid film buffer material at the time of the collision of the freezing granule 1b. Therefore, the front and back surfaces of the board | substrate 6 can be wash | cleaned favorably, reliably preventing damage to the board | substrate 6 by the collision of the freezing lip 1b. In addition, since the frozen lip 1b does not fly after the collision and the particles removed by the collision of the frozen lip 1b are washed off by the cleaning liquid 3, the removed particles may recontaminate the substrate 6. There is no concern, and a full pollution prevention effect is exhibited.

Moreover, since the washing | cleaning slurry 4 is a mixed fluid of the freezing granule 1b and the washing | cleaning liquid 3 which is a low temperature liquid which does not melt | dissolve it, that is, it is a low temperature fluid below 0 degreeC, it adheres to the board | substrate 6 Organic substances, such as a resist film, are easy to solidify and shrink | contract and remove, and the washing | cleaning effect further improves. In addition, since the cleaning slurry 4 is a low temperature fluid and has a low vapor pressure, there is no fear of fire, and the substrate can be safely cleaned. In particular, when an organic compound such as isoprop alcohol is used as the cleaning liquid 3, unlike the case where water is used, a natural oxide film is not formed on the substrate 6. In addition, even when the cleaning liquid 3 is an organic compound containing water, such as a mixture of acetone and water, the increase in the film thickness of the natural oxide film can be effectively suppressed compared with the case where water is used alone.

In the injection guns 34 and 34, a three-phase mixed fluid of solid (copper granules 1b, liquid (cleaning liquid 3) and gas (carrier gas 8) is sprayed on the front and back surfaces of the substrate 6; By adjusting these mixing ratios, the cleaning power can be easily controlled, and optimal cleaning can be performed according to the properties of the substrate 6.

In addition, since the freezing granulation container 10 and the cleaning liquid storage container 21 are directly connected to each other, and the cleaning slurry 4 is a low temperature fluid, the used freezing granules 1b to low temperature liquid, which are cleaning residues, are used. In addition to recovering the cleaning liquid 3 to the cleaning liquid storage container 21, waste from the cleaning system and excess cooling heat can be recovered and used effectively, and the running cost can be reduced. In addition, not only the cleaning effect by the freezing lip 1b but also the cleaning effect by the cleaning liquid 3 are exerted, so that freezing is required as compared to an ice scrubber which cleans only with the freezing lip (ice particles) described above. The number of rips is greatly reduced, whereby the running cost of the freeze-lip manufacturing apparatus 1 and the entire cleaning system can be further reduced.

In addition, this invention is not limited to said embodiment, It can improve suitably and change in the range which does not deviate from the basic principle of this invention.

For example, as the raw material water supply mechanism 11 is disclosed in Japanese Patent Application Laid-Open No. 3-52369 or Japanese Patent Application Laid-Open No. 5-144794, the raw material water 1 is freeze granulated production vessel 10. It can be configured to spray supply indirectly to. In addition to using the above-mentioned freezer, the cooling mechanism 22 can be configured to directly cool the cleaning liquid storage container 21 by cooling with liquid nitrogen or the like. In addition, depending on the cooling temperature of the storage cleaning liquid 3 required, the cooling heat in the freezing granulation vessel 10 directly connected to the cleaning liquid storage container 21 may be used.

In addition, if necessary, a rinse facility using pure water or the like can be provided in the cleaning treatment chamber 7, and research is performed to reliably prevent recontamination by particles by rinsing after the main cleaning by the cleaning slurry 4. It is possible. As a result of being washed by the cleaning liquid 3, the substrate 6 is difficult to reattach the removed particles, but, for example, even if the removed particles are reattached, their adhesion is weak, so that the above-mentioned rinsing is easily performed. Removed.

In the case where the cleaning system has been used for cleaning, the filter 33 in the cleaning residual water mechanism 30 does not need this particularly.

As can be easily understood from the above description, according to the substrate cleaning system of the present invention, the same problems as those caused by the brush scrubber or the ice scrubber described earlier (for example, the secondary contamination of the substrate or the destruction of the element, etc.) The substrate can be cleaned well and effectively without generating.

Claims (7)

A freezing granules manufacturing device for producing fine freeze granules using water as a raw material, and a freezing granules prepared by the freeze granulation device are mixed with a liquid having a freezing point lower than water as a liquid having a lower temperature than the freezing point of water to prepare a cleaning slurry. And a cleaning slurry spraying device for spraying and colliding the cleaning slurry produced by the cleaning slurry manufacturing apparatus toward the substrate held in the cleaning processing chamber. Substrate cleaning system. The substrate cleaning system according to claim 1, wherein the cleaning liquid is a liquid which does not adversely affect the substrate. The substrate cleaning system according to claim 2, wherein the cleaning liquid is isopropyl alcohol, methyl alcohol, ethyl alcohol, acetone, or a mixture of any of these and water. The substrate cleaning system according to claim 1, wherein the cleaning slurry contains 1 to 20 wt% of freezing granules. The freeze granulation production apparatus according to claim 1, wherein the freezing granulation production apparatus includes a freezing granulation production vessel in which the inside is held in a cold air atmosphere, and a raw water supply mechanism for supplying the raw water as fine granules in the container. A substrate cleaning system, characterized in that it is configured to manufacture a frozen lip. 6. The cleaning slurry production apparatus according to claim 5, wherein the cleaning slurry production apparatus is connected to the freezing granulation production vessel, and the cleaning liquid storage container in which the freezing granules are dropped and supplied from the freezing granulation production vessel, and the cleaning liquid in the vessel is cooled to -5 to -40 deg. And a cooling mechanism to keep warm, and a mixing and stirring mechanism to mix and stir the cleaning liquid and the freezing granules in the cleaning liquid storage container to uniformly disperse the frozen granules in the cleaning liquid. The cleaning residual water mechanism for recovering the cleaning slurry used for cleaning the substrate from the cleaning processing chamber to the cleaning slurry manufacturing apparatus is provided so as to reuse the frozen granules or the cleaning liquid. Substrate cleaning system, characterized in that.