JP2003117499A - Ultra-precision cleaning apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultra-precision cleaning apparatus which does not use a chemical at all and can remove not only formerly unremovable foreign matters with a particle size of 0.01 μm order but also a metal contaminant of an atomic/ molecular level. SOLUTION: This ultra-precision cleaning apparatus is equipped with a pair of or a plurality of pairs of high-pressure nozzles 2 for jetting ultrapure water which are arranged in a cleaning tank 1 filled with ultrapure water at mirror image symmetry positions so that a cleaning area is secured between the nozzles; a wafer drive mechanism 4 which, while holding the edge of a flat object 3 to be cleaned (e.g. a semiconductor wafer), supplies the object in such a way as to traverse the cleaning area and recovers it after cleaning; and a circulation system 7 which jets ultrapure water from the high-pressure nozzles to both the surfaces of the object while controlling the pressure balance to the both surfaces of the object, cleans the object by generating a high-speed shear flow of ultrapure water jetted from the high-pressure nozzles at the vicinity of the surface of the object, removes fine particles dissolved in ultrapure water in the cleaning tank with a filter, and returns the ultrapure water again to the cleaning tank.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to cleaning semiconductor wafers (Si, GaAs, etc.), cleaning liquid crystal substrates, cleaning optical disks, magneto-optical disks, thin-film magnetic heads, etc., precision cleaning of ultra-precision optical parts, next generation. Related to the ultra-precision cleaning equipment capable of ultra-precision cleaning compatible with highly integrated semiconductor wafers. More specifically, it is possible to realize removal of foreign particles and particles of various impurities with a particle size of 0.01 μm order on the surface to be cleaned. Ultra precision cleaning equipment.

[0002]

2. Description of the Related Art With the high integration of semiconductor devices and the sophistication of microelectronics technology, in the field of manufacturing semiconductor wafers and liquid crystal substrates, in the field of manufacturing electronic devices, etc. The introduction of cleaning technology is required. Today, even foreign particles with a diameter of 0.1 μm or less adhering to the substrate have to be removed, and various methods have been tried, but chemical cleaning using a high-concentration chemical solution and 1 MHz or more Although the combined use of physical cleaning such as ultrasonic cleaning using the above high frequency has also been promoted, the present situation is that the removal rate is insufficient or defects are introduced on the surface of the object to be cleaned.

The chemical cleaning using a high-concentration chemical liquid such as CFC has a problem that the cleaning liquid has a great influence on the environment. Further, it is said that the high frequency ultrasonic cleaning which is often used at present is not the cleaning by cavitation unlike the conventional ultrasonic cleaning, and thus the damage on the wafer surface is small. However, in view of the practical removal rate, the removal of fine particles having a particle size of at most about 0.3 μm is the limit. In addition, although a cleaning technology using an ultrapure water jet flow has been recently developed, it is inevitable to introduce defects on the cleaning surface because it utilizes the mechanical impact of an air jet flow. Supply pressure to the nozzle is at most 5
Only one of about 0 atm has been developed. In addition, these cleaning methods cannot remove metal contaminants.

Under these circumstances, it goes without saying that great expectations are placed on the development of new cleaning techniques capable of solving these problems. The inventors of the present invention used ultrapure water to remove metal contamination, etc.
We have developed a technology to pressurize ultra high pressure of 000 atm or more (Japanese Patent Laid-Open No. 2001-73930). We have developed a technology to stably generate a pure water shear flow (velocity gradient of several tens of m / sec · μm) and demonstrated that it is possible to remove fine particles on the surface of the order of 0.01 μm ( JP 2000-1
73965 publication). Also, by applying the catalyst technology, we succeeded in producing extremely high concentration OH ⁻ ions in ultrapure water without adding chemicals, and transporting these OH ⁻ ions to the surface to be cleaned by an external electric field, and various ionization. It has been found that it is possible to completely remove fine metal impurities, which were difficult to remove by conventional ultrasonic cleaning or the like, by using the chemical elution reaction with the metal atom together (Japanese Patent 20
00-173970). Moreover, the metal contaminants once removed by the above-mentioned high-speed shearing flow can be prevented from reattaching to the surface of the object to be cleaned, and the cleaning can be efficiently performed. Also,
A high-concentration slurry refining system for removing fine particles dissolved in ultrapure water and recycling it has already been developed (Japanese Patent Laid-Open No. 2000-15012). In this high-concentration slurry refining system, a high-speed shear flow is generated on the filter membrane surface to prevent the accumulation of fine particles on the membrane surface and enable efficient filtration.

As described above, the present cleaning technique proposes a completely new cleaning technique that combines these chemical action and physical action, and is unprecedented in the conventional cleaning technique. In addition, this high-speed shear flow on the cleaned surface is extremely effective for precision cleaning of functional materials such as electronic materials without giving a mechanical impact to the cleaned surface. It is also worth noting that it is a new technology that is extremely clean and eco-friendly without using it.

[0006]

DISCLOSURE OF THE INVENTION In order to remove the impurity metal attached to the surface of the object to be cleaned accompanied by a chemical bond, the inventors of the present invention apply a shear flow of a predetermined strength or more to the surface of the object to be cleaned. It is theoretically predicted and confirmed in experiments that it is necessary, that is, that a certain velocity gradient of the shear flow is required, and chemical elution of hydroxide ions and impurity metals in ultrapure water is performed. It was found that it is effective to use the reaction in combination.

In view of the above situation, the present invention intends to solve the problems by combining the physical action of high-speed shear flow of ultrapure water with the electrochemical action of OH ⁻ ions in ultrapure water. By using the technology that can obtain an ultra-clean surface, no chemicals are used, and not only the removal of foreign substances with a particle size on the order of 0.01 μm, which was impossible in the past, but also the atomic and molecular level metal contamination It is an object of the present invention to provide an ultra-precision cleaning device that can be removed.

[0008]

In order to solve the above problems, the present invention provides a single or a plurality of high pressure nozzles for injecting high pressure ultrapure water into a cleaning area in a cleaning tank filled with ultrapure water. And a wafer drive mechanism for holding the edge of the object to be cleaned and supplying the object to be cleaned so as to cross the cleaning area and recovering after cleaning, and a high-pressure nozzle near the surface of the object to be cleaned. Generated by high-speed shear flow of ultrapure water injected from
An ultra-precision cleaning device was provided with a circulation system for removing fine particles dissolved in ultrapure water in the cleaning tank with a filter and supplying again to the cleaning tank. Thereby, by the high-speed shear flow in the vicinity of the surface of the object to be cleaned made by the ultrapure water injected from the high-pressure nozzle, the fine foreign matter adhering to the surface of the object to be cleaned is removed by cutting the bond with the surface, The removed foreign matter was prevented from reattaching to the surface by the flow of high-speed shear flow.

Further, according to the present invention, a cleaning tank filled with ultrapure water is provided with a pair of or a plurality of pairs of high-pressure nozzles for injecting ultrapure water of high pressure, and a cleaning region is provided between them to arrange them in a mirror image symmetrical position. A wafer drive mechanism that holds the edge of a flat object to be cleaned such as a semiconductor wafer and supplies the object to be cleaned so as to cross the cleaning region and recovers the object after cleaning. An ultra-precision cleaning apparatus was constructed by injecting ultrapure water from the high-pressure nozzle onto both sides of the object to be cleaned while controlling the pressure balance with respect to. As a result, both sides of the flat object to be cleaned such as a semiconductor wafer can be efficiently cleaned.

Further, by placing an ion exchange material or a catalyst material for increasing hydroxide ions in the cleaning tank or in the ultrapure water circulation system, the hydroxide ion concentration in ultrapure water can be dramatically increased. The fine impurity metal adhering to the surface of the object to be cleaned can be efficiently separated from the surface of the object to be cleaned by the chemical elution reaction with hydroxide ions and the high-speed shear flow.

Further, an electrode for ion transport having a potential lower than the potential of the object to be cleaned is arranged in the cleaning tank to form a potential gradient between the surface of the object to be cleaned and the electrode for ion transportation, It is also preferable to introduce the oxide ions to the surface of the object to be cleaned and the hydrogen ions to the ion transport electrode.
In practice, the cleaning tank is grounded and a voltage is applied between the object to be cleaned and the electrode for ion transport so that the object to be cleaned has a positive potential and the electrode for ion transport has a negative potential. The oxide ions are attracted to the object to be cleaned.

Further, in the present invention, the injection direction of ultrapure water from the high-pressure nozzle can be adjusted to an angle of 0 to 90 degrees with respect to the surface of the object to be cleaned. By making the jet direction of ultrapure water have an inclination angle with respect to the surface of the object to be cleaned, a high-speed shear flow along the surface of the object to be cleaned can be stably formed, and the separated fine foreign matter is made to flow to the downstream side. Since it can be quickly removed from the surface, it is effective in preventing redeposition on the surface.

Here, if the jet port of the high-pressure nozzle is a slit hole, the surface of the object to be cleaned can be cleaned in a line, and the cleaning efficiency can be improved.

Further, in the present invention, as the wafer drive mechanism, a two-system belt drive system in which an endless belt having a groove for fitting an edge portion of the object to be cleaned is formed on the outer periphery is stretched by a plurality of pulleys. And having linear portions of both belts arranged parallel to each other on both sides of the cleaning region, and elastically holding the edge of the object to be cleaned in the grooves of the linear portions of both belts, and at least one of the belt drive systems. One pulley is used as a drive pulley and is rotated by a motor, and both belts are driven to supply or recover the object to be cleaned to the cleaning area.

Here, if the rotational speeds of the drive pulleys of the belt drive systems can be set independently, both belts are driven in the same direction by synchronizing the feed speeds of their linear portions to be cleaned. An object is supplied to the cleaning area in a non-rotating state or is recovered from the cleaning area, or both belts are driven by non-synchronizing the feed speeds of their linear portions to supply the object to be cleaned while rotating the object to be cleaned, or It is possible to rotate the object to be cleaned at a fixed position by recovering it from the cleaning area or by driving both belts in the opposite directions by synchronizing the feed speeds of their linear portions.

Further, as the wafer driving mechanism of another structure, a pair of arms, which are spaced apart from each other and can be moved in parallel, are fitted to the insides of the tips of the arms at the edges of the object to be cleaned. The holding members having grooves are stretched in parallel with each other, the edges of the object to be cleaned are elastically held in the grooves of both holding members, and both arms are synchronized and driven in the same direction to perform the cleaning. It is also preferable to employ a product obtained by supplying an object to the cleaning region or recovering it from the cleaning region.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows the cleaning principle of the present invention, and FIGS. 2 to 5 show the outline of an ultra-precision cleaning apparatus according to the present invention. In the drawing, reference numeral 1 is a cleaning tank, 2 is a high pressure nozzle, 3 is a semiconductor wafer, and 4 is a semiconductor wafer. Is a wafer drive mechanism, 5 is an ion exchange material, 6 is an ion transport electrode, and 7 is a circulation system of ultrapure water. In the following embodiments, the cleaning of the semiconductor wafer 3 will be described, but the present invention is not limited to the removal of the contaminant metal adhering to the surface of the semiconductor wafer 3,
It is naturally effective in removing other particles and organic pollutants. Furthermore, the present invention uses S as a cleaning target.
Not limited to semiconductor wafers such as i-wafers, but widely used for electronic device substrates including liquid crystal substrates, optical discs, magneto-optical discs, thin-film magnetic heads, and other ultra-precision optical components, and the surface of next-generation highly integrated semiconductor wafers. It can be applied to cleaning.

As shown in FIGS. 1 and 2, the semiconductor wafer ultra-precision cleaning apparatus of the present invention comprises a pair or a plurality of pairs for injecting high-pressure ultrapure water into a cleaning tank 1 filled with ultrapure water. The high-pressure nozzles 2 and 2 are provided in a mirror image symmetrical position with a cleaning region C provided therebetween, and the semiconductor wafer 3 is supplied and cleaned so as to cross the cleaning region C while holding the edge of the semiconductor wafer 3. A wafer drive mechanism 4 for post-collection is provided, and the high pressure nozzles 2 are provided on both sides of the semiconductor wafer 3 while controlling the pressure balance on both sides of the semiconductor wafer 3.
Ultrapure water is sprayed from 2 to generate a high-speed shear flow of ultrapure water sprayed from the high-pressure nozzle 2 in the vicinity of the surface of the semiconductor wafer 3 for cleaning, and fine particles dissolved in the ultrapure water in the cleaning tank 1 Is removed by a filter (not shown) and supplied again into the cleaning tank 1 with a circulation system 7.

The cleaning principle of the present invention is as shown in FIG.
Hydroxide ions generated by spraying ultrapure water from the high-pressure nozzles 2 and 2 onto the surface of the semiconductor wafer 3 placed in the ultrapure water in the cleaning tank 1 to decompose the water molecules a of the ultrapure water. b is supplied to the surface, and the reactant f generated by the reaction of the pollutant metal e (metal atoms or agglomerated fine metal lumps) adhering to the constituent atoms d of the semiconductor wafer with the hydroxide ion b is ultrapure water. The surface of the semiconductor wafer 3 is eluted by the flow of ultrapure water along the surface of the semiconductor wafer 3. It is washed by removing it from the.

As is well known, in ultrapure water,
Hydroxide ion (OH ^-) Is small (25 ℃
At 10^-7mol / l) but present. Only
However, since the amount of hydroxide ion in ultrapure water is very small, it is practical
In some way, a hydroxide
The on-density must be increased. In the present invention,
Increase hydroxide ion b without adding the solution of
Therefore, the ion exchange material 5 or the catalyst material is placed in ultrapure water.
Then, increase the hydroxide ion density in ultrapure water,
Try to wash the material in a clean environment
There is.

Further, an ion transporting electrode 6 is arranged so as to face the semiconductor wafer 3, and the ion transporting electrode 6 is set to a potential lower than the potential of the semiconductor wafer 3 so that the surface of the semiconductor wafer 3 and the ions are A potential gradient is formed between the transport electrodes 6 to guide the hydroxide ions b to the surface of the semiconductor wafer 3 and hydrogen ions c to the ion transport electrodes 6.
To improve the cleaning efficiency. actually,
The cleaning tank 1 is grounded so that the semiconductor wafer 3 has a positive potential and the ion transport electrode 6 has a negative potential.
By applying a voltage between the ion transport electrode 6 and the ion transport electrode 6, hydroxide ions are attracted to the semiconductor wafer by the Coulomb force. When the impurity metal is in the positive ion state, the electric repulsive force is used to make the semiconductor wafer 3
It is also possible to promote the separation of the impurity metal from the surface.

Next, it was estimated how much shear flow strength (velocity gradient) is required on the surface of the semiconductor wafer in order to remove the fine particles attached to the surface of the semiconductor wafer along with chemical bonds. When ZrO ₂ fine particles with a particle diameter of 0.1 μm are adsorbed on the Si (100) surface in ultrapure water and a shear flow of ultrapure water of various strengths is applied to this surface, the particles are removed from the Si surface. The state of removal was observed with an optical microscope. As a result, it was found that effective removal of fine particles proceeds when the velocity gradient of about 5 m / sec · μm is exceeded. From this result, it was found that the cleaning requires a shear flow with a certain velocity gradient or more, but the lower limit thereof is expected to change depending on the material of the semiconductor wafer and the type and particle size of the adhered fine particles. However, by using the high-speed shear flow by the high-pressure nozzle 2 and the above-mentioned means for increasing the hydroxide ion density by the ion exchange material 5 and the means for applying a voltage with the semiconductor wafer as the anode, the required shear flow rate can be obtained. It is possible to reduce the slope.

Here, the force exerted by the jet of ultrapure water ejected from the high pressure nozzle on the surface of the semiconductor wafer 3 will be estimated. As described in JP-A-2000-173970, when high pressure ultrapure water of 1000 atm is jetted from a nozzle having a diameter of 0.1 mmφ at right angles to the surface of the object to be cleaned, the nozzle and the object to be cleaned are It has been confirmed by simulation that when the gap distance between the surfaces is several mm, the flow velocity is approximately constant (400 to 450 m / s) up to about 100 μm from the surface of the object to be cleaned. Therefore, assuming that the supply pressure of the high-pressure ultrapure water is 1000 atm and the pressure loss is minimized, the slit hole of the high-pressure nozzle has a width of 15 mm.
Assuming that the flow rate is 0 mm and the vertical width is 50 μm, the angle is 30 degrees with respect to the surface of the semiconductor wafer, and the flow velocity is 450 m / s in the vicinity of the surface, the total surface area of the semiconductor wafer is 37.5 kg in the vertical direction. Will be applied. Therefore, as the angle to the semiconductor wafer surface increases, the balance of the high pressure nozzles on both sides of the semiconductor wafer becomes very important. In addition, flow velocity 1
If the other conditions are the same at 00 m / s, the force is a little less than 2 kg. However, when the angle of the high-pressure nozzle with respect to the surface of the object to be cleaned (semiconductor wafer) is small, the force applied in the direction perpendicular to the surface of the object to be cleaned is small, and there is no restriction on the pressure balance on both sides. It is possible to clean only one side of the object to be cleaned by disposing a high pressure nozzle on one side of the object to be cleaned.

Further, when water pressurized to 1000 atm is jetted into water from a nozzle having a diameter of 0.1 mm and irradiated onto a solid surface, a strong shear flow exceeding several tens of m / sec.μm can be generated on the surface. Is shown by theoretical calculation. Furthermore, it has very strong adhesion to the Si wafer surface.
It has been experimentally shown that even when ZrO ₂ fine particles (diameter of 0.01 μm) are attached, it can be removed by a shear flow of about 10 m / sec · μm, and high-speed shear created by the jet flow in ultrapure water. It has been confirmed that the stream is extremely effective as the basic technology of the new ultra-precision cleaning technology. Furthermore, in the comparison by the flow analysis simulation in the case of the nozzle shape of the circular hole and the slit hole, the slit-shaped nozzle is slower in the attenuation of the high-speed flow even if the discharge speed is slower, and it is necessary to remove the fine particles in a wider range. It has been proved by experiments that it can generate a strong surface shear flow and is more effective as a cleaning head. Moreover, the generation of bubbles (cavitation) near the nozzle damages the surface to be cleaned, but the mechanism was also analyzed and countermeasures were examined. That is, it is found that bubbles are more likely to occur as the velocity gradient of the discharge flow in the immediate vicinity of the high pressure nozzle is larger,
The shape of the discharge port and the internal flow path were examined, and the effect was verified by experiments.

According to the present invention, the physical action of high-speed shearing flow and the chemical elution reaction of hydroxide ion and impurity ion in ultrapure water are used together for cleaning. In order to promote this, it is important to increase the OH ⁻ ion density near the surface to be cleaned. The present inventors have already analyzed the ionization reaction of H ₂ O molecules by a catalyst material (for example, a sulfonic acid group) by a simulation, and in order to effectively cause the ionization reaction and increase the OH ⁻ ion density, Experiments have demonstrated that the optimal structure of the active site carrier is important. For example, normal PTFE
Even when resin is used as catalyst carrier, but without catalyst
It was found that a current of 10000 times as much as (theoretical value in the case of only ultrapure water) flows, and when a graft-polymerized fiber is used as a carrier, a current of 100 to 1000 times that current flows. We have found promising development of catalyst units as carriers.

As described above, according to the present invention, the high pressure nozzle has 10
Ultrapure water of 0 to 1000 atm is supplied to generate ultrahigh-speed flow of 100 m / sec or more without cavitation in ultrapure water, and high-speed shear flow of several tens of m / sec · μm or more is applied to the surface of the object to be cleaned. generate. At this time, in order to generate a stable shear flow without cavitation, it is very important to use the discharge flow into ultrapure water instead of the air and to optimize the nozzle shape. Then, at the position where the maximum shear flow is generated on the object to be cleaned, for example, a polymer fiber having a sulfonic acid group is arranged, which serves as a catalyst to promote the dissociation of water molecules, and the electric field applied to the same position. O on the surface to be cleaned
Due to the electrochemical action of H ⁻ ions and the physical action of the high-speed shearing flow, atomic and molecular metal adsorbates on the object to be cleaned can be promptly removed, and can be removed together with foreign particles on the order of 0.01 μm.

In the ultra-precision cleaning apparatus of the present invention, ultra-high-pressure ultra-pure water pressurized to about 100 to 1000 atm by a pressurizing apparatus is supplied to the high-pressure nozzle 2 and discharged from the cleaning tank 1 to avoid contamination An ultrapure water circulation system 7 is provided to remove impurities from the pure water by a microfiltration device and supply the purified water again to the pressurizing device. Here, the pressurizing device and the microfiltration device have already been developed.

The high-pressure nozzle 2 has a slit-shaped discharge port, and even a large object to be cleaned can be cleaned by one-way scanning. And large liquid crystal and large diameter Si
In order to clean wafers and the like, the size is set to allow cleaning of the substrate within the actual wafer size width. In this apparatus, two high-pressure nozzles 2 and 2 are arranged to face each other in ultrapure water, and an object to be cleaned (semiconductor wafer) can be moved between the two nozzles. At this time, it is taken into consideration that the once removed metal contaminants and foreign particles are not reattached to the surface of the semiconductor wafer due to the downflow flow in the ultrapure water.

More specifically, the structure of each part will be described with reference to FIGS. The wafer driving mechanism 4 has a V-shaped groove 10 that fits the edge of the semiconductor wafer 3 on the outer circumference.
The endless belt 9 having the above-mentioned structure is stretched by a plurality of pulleys 11, ..., and has two systems of belt drive systems 8, 8 and linear portions 9A, 9A of both belts 9, 9 are provided on both sides of the cleaning area. The belts 9 and 9 are arranged in parallel to each other and are straight portions 9A and 9
The edges of the semiconductor wafer 3 are elastically held in the grooves 10, 10 of A, and at least one pulley of each belt drive system 8, 8 is rotated by a motor 13 as a drive pulley 12, so that both belts 9, 9 are rotated. Is driven to supply or recover the semiconductor wafer 3 to or from the cleaning region.

Here, the belt 9 is made of a non-swelling material such as polyurethane or tetrafluoroethylene resin. Further, in order to increase the tensile strength of the belt 9, it is also effective to embed a reinforcing core such as a metal wire, carbon fiber or glass fiber inside.

The belt drive system 8 has one end fixed to the outside of the cleaning tank 1 and is provided on a belt holding member 14 extending from the upper portion of the cleaning tank 1 into ultrapure water.
Driven pulleys 11A and 11B are arranged on the upper and lower sides of the cleaning area, the portion of the belt 9 between the driven pulleys 11A and 11B forms the linear portion 9A, and the drive pulley 12 is arranged on the upper outer side, The belt 9 between the drive pulley 12 and the driven pulley 11B below is pressed to press the belt 9.
Is provided with a tension pulley 11C for maintaining the tension at a predetermined tension. Here, the upper and lower driven pulleys 11A, 1
1B is adapted to be able to change the position in the horizontal direction, so that the linear portions 9A of both belt drive systems 8 and 8,
The distance of 9 A can be adjusted according to the diameter of the semiconductor wafer 3. Along with this, the tension pulley 11C can also be changed in position. However, when cleaning the semiconductor wafer 3 having a predetermined size, the driven pulleys 11A and 11B may be fixed.

.. and drive pulley 12
Is immersed in ultrapure water, a fluid bearing mechanism is adopted so that particles and organic impurities are not generated from the bearing portion thereof, and the rotary shaft 1 of the drive pulley 12 is used.
The motor 5 arranged outside the cleaning tank 1 is completely cut off, and the rotation is transmitted by the magnetic coupling 16.

The high-pressure nozzle 2 has one end held outside the cleaning tank 1 and is provided at the lower end of a nozzle holding member 17 extending from the upper portion of the cleaning tank 1 into ultrapure water. The direction in which the high-pressure nozzle 2 jets ultrapure water is changed to the semiconductor wafer 3
It can be adjusted to an angle of 0 to 90 degrees with respect to the surface of (the object to be cleaned). Each of the nozzle holding members 17, 17 provided with the high-pressure nozzle 2 is attached to the cleaning tank 1 via a linear drive mechanism 18 arranged outside the cleaning tank 1 so that the distance between the nozzles can be adjusted. . Here, the linear drive mechanism 18 includes a linear guide and an air cylinder or a ball screw feeder.

Here, the rotational speeds of the drive pulleys 12, 12 of the belt drive systems 8, 8 can be independently set, and the two belts 9, 9 are synchronized with the feed speed of the linear portions 9A, 9A. Then, the semiconductor wafer 3 (object to be cleaned) is supplied to the cleaning area in a non-rotating state or recovered from the cleaning area by driving in the same direction, or both belts 9 and 9 are fed at their linear portions 9A and 9A. The semiconductor wafer 3 (object to be cleaned) is supplied to the cleaning area or recovered from the cleaning area by rotating the semiconductor wafer 3 (object to be cleaned) by rotating the belts 9 and 9 at the feed rate of the linear portions 9A and 9A. It is possible to rotate the semiconductor wafer 3 (object to be cleaned) at a fixed position by synchronizing and driving in the opposite direction.

Since the semiconductor wafer 3 has a cut portion for positioning on the outer periphery, cleaning while rotating the semiconductor wafer 3 does not mean that the semiconductor wafer 3 is rotated completely once but the direction of the high-speed shear flow. It means that the cleaning is performed by changing the direction of the cleaning surface. Needless to say, it is necessary to clean the object to be cleaned while rotating it only when the cleaning effect is better than when cleaning the object to be cleaned in the non-rotating state.

The high-pressure nozzle 2 is shown in detail in FIGS. This high-pressure nozzle 2 is designed to withstand ultra-high pressure up to 1000 atm, and has a slit-shaped discharge port 19 with a width of 150 mm and a length of 50 μm at the tip.
Is provided. The high-pressure nozzle 2 has a flow passage 21 extending from the side to the tip side inside a main body 20 made of a block body made of SUS, and two outlets 22 and 22 are superposed on the outlet portion of the flow passage 21. In this state, it is fixed to the main body 20 with the fixing metal fitting 23, and the discharge port 19 is formed between the caps 22 and 22. Therefore, the dimensions of the discharge port 19 can be changed by exchanging the caps 22, 22. The high pressure nozzle 2 is attached to the nozzle holding member 17 so that the angle can be changed, and the pressurized ultrapure water supply system 24 is provided.
It is connected to the.

As described above, the high-pressure ultrapure water is jetted from the discharge ports 19, 19 of the pair of high-pressure nozzles 2 arranged in the ultrapure water in the cleaning tank 1, and the wafer driving mechanism is provided in the cleaning area between them. The semiconductor wafer 3 whose edges are elastically held is supplied to the linear portions 9A and 9A of both belts 4 and 9 of No. 4, and both surfaces thereof are simultaneously cleaned. The ultrapure water after cleaning is
It is discharged from the lower part of the washing tank 1 that has a backflow prevention structure,
The ultrapure water circulation system 7 is sent to perform microfiltration, pressurizes it to a predetermined pressure by a pressurizing device, and ejects it again from the high-pressure nozzle 2 through the pressurized ultrapure water supply system 24.

9 to 12 show a second embodiment of the ultra-precision cleaning device of the present invention. The ultra-precision cleaning apparatus of this embodiment employs a wafer drive mechanism 4 having a structure different from that of the first embodiment. That is, the wafer drive mechanism 4 has a groove 27 on the inner surface side for fitting the edge portion of the semiconductor wafer 3 inside the respective tip end portions of the pair of arms 25, 25 which are spaced apart from each other and can be moved in parallel. The formed holding members 26 are stretched in parallel with each other, and both holding members 26, 26
The edges of the semiconductor wafer 3 are elastically held in the grooves 27, 27, and both arms 25, 25 are synchronized and driven in the same direction to supply the semiconductor wafer 3 to or from the cleaning area. It is a structure to collect.

More specifically, the horizontal linear drive mechanism 30 is attached to the movable portion 29 of the vertical linear drive mechanism 28 attached to the outer upper portion of the cleaning tank 1, and the upper end portion of the arm 25 is fixed to the movable portion 31. ing. Therefore, the two horizontal linear drive mechanisms 30, 30 are driven in the directions in which they approach each other, and the holding members 26, 2 stretched on the tips of the arms 25, 25.
The semiconductor wafer 3 is sandwiched between 6 and then both vertical linear drive mechanisms 28, 28 are synchronized and driven downward, so that the semiconductor wafer 3 is supplied to the cleaning region between both high pressure nozzles 2, 2. Further, in order to collect the semiconductor wafer 3 after cleaning, both vertical linear drive mechanisms 28, 28 are synchronized and driven upward, and both horizontal linear drive mechanisms 30,
The semiconductor wafer 3 is removed by driving the 30 away from each other.

In order to adjust the angle of the high pressure nozzle 2, the main body 20 of the high pressure nozzle 2 is rotatably attached to the tip of the nozzle holding member 17, and the high pressure nozzle 2 is connected via a link mechanism 32. It is driven by the angle adjusting mechanism 33.

[0041]

The ultra-precision cleaning apparatus of the present invention as described above does not use chemicals or the like, and does not use metal ions adhering to flat objects to be cleaned such as semiconductor wafers in a clean environment of only ultrapure water. It is possible to remove foreign particles having a particle size of 0.01 μm order. As an application, for example, not only can it be expected as an ultra-precision cleaning apparatus for semiconductor wafers, especially as a standard ultra-precision cleaning apparatus for highly integrated semiconductor wafers in the future, but also as a synchroton radiation mirror and an ultra-high performance X
It can also be expected as a cleaning device for ultra-precision optical components such as line mirrors. Further, this technique can be applied to a cleaning process for liquid crystals, magnetic thin films, and the like. Furthermore, cleaning technology is essential in almost all fields of various manufacturing industries, and is very effective from the environmental aspect, which has recently been regarded as a problem.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the cleaning principle of the present invention.

FIG. 2 is a conceptual diagram of an ultra-precision cleaning device according to the first embodiment.

FIG. 3 is a partially vertical front view of the same.

FIG. 4 is likewise a partial vertical cross-sectional side view.

FIG. 5 is a plan view of the same.

FIG. 6 is a side view of a high pressure nozzle.

FIG. 7 is a plan view of the same high pressure nozzle.

FIG. 8 is a front view of the same high pressure nozzle.

FIG. 9 is a partial vertical sectional front view of the ultra-precision cleaning device of the second embodiment.

FIG. 10 is a partial vertical sectional side view of the same.

FIG. 11 is a plan view of the same.

FIG. 12 is a partially enlarged front view showing a state in which a semiconductor wafer is held between the tips of both arms.

[Explanation of symbols]

1 cleaning tank 2 high pressure nozzle 3 Semiconductor wafer (object to be cleaned) 4 Wafer drive mechanism 5 Ion exchange material 6 Ion transport electrodes 7 Ultrapure water circulation system 8 Belt drive system 9 belt 9A Belt straight section 10 grooves 11 pulley 11A, 11B driven pulley 11C tension pulley 11C tension pulley 12 Drive pulley 13 motor 14 Belt holding member 15 rotation axis 16 Magnet coupling 17 Nozzle holding member 18 Linear drive mechanism 19 outlets 20 body 21 channel 22 Clasp 23 Fixing bracket 24 pressurized ultrapure water supply system 25 arms 26 Holding member 27 grooves 28 Vertical linear drive mechanism 29 Moving part 30 Horizontal linear drive mechanism 31 Moving part 32 link mechanism 33 Angle adjustment mechanism

Claims (9)

[Claims] 1. A single or a plurality of high-pressure nozzles for injecting high-pressure ultrapure water into a cleaning region is provided in a cleaning tank filled with ultrapure water, and the edge of an object to be cleaned is held. A wafer drive mechanism that supplies the object to be cleaned across the cleaning area and recovers the object after cleaning is provided, and a high-speed shear flow of ultrapure water injected from a high-pressure nozzle is generated near the surface of the object to be cleaned for cleaning. An ultra-precision cleaning device comprising a circulation system for removing fine particles dissolved in ultrapure water in a cleaning tank with a filter and supplying the particles again into the cleaning tank. 2. A semiconductor wafer in which a cleaning tank filled with ultrapure water is provided with a pair or a plurality of pairs of high-pressure nozzles for injecting high-pressure ultrapure water, and a cleaning region is provided between them in a mirror image symmetrical position. A wafer drive mechanism that holds the edge of a flat object to be cleaned and supplies the object to be cleaned so as to cross the cleaning area and recovers the object after cleaning is provided. The ultra-precision cleaning device according to claim 1, wherein ultra-pure water is sprayed from both the high-pressure nozzles onto both surfaces of the object to be cleaned while controlling. 3. The ultraprecision cleaning device according to claim 1, wherein an ion exchange material or a catalyst material for increasing hydroxide ions is arranged in the cleaning tank or in a circulation system of ultrapure water. 4. An ion transport electrode having a potential lower than the potential of the object to be cleaned is arranged in the cleaning tank to form a potential gradient between the surface of the object to be cleaned and the electrode for ion transportation, The ultraprecision cleaning device according to any one of claims 1 to 3, wherein the oxide ions are guided to the surface of the object to be cleaned and the hydrogen ions are guided to the electrode for ion transport. 5. The ultra-precision cleaning device according to claim 1, wherein the jet direction of the ultra-pure water of the high-pressure nozzle can be adjusted to an angle of 0 to 90 degrees with respect to the surface of the object to be cleaned. 6. The ultraprecision cleaning device according to claim 1, wherein the ejection port of the high-pressure nozzle is a slit hole. 7. The wafer drive mechanism has a two-system belt drive system in which an endless belt having a groove for fitting an edge portion of the object to be cleaned is formed on the outer periphery by a plurality of pulleys. Linear parts of both belts are arranged parallel to each other on both sides of the cleaning area, and the edges of the object to be cleaned are elastically held in the grooves of the linear parts of both belts, and at least one pulley of each belt drive system is provided. 7. The drive pulley is rotated by a motor and both belts are driven to supply or recover the object to be cleaned into the cleaning area.
The ultra-precision cleaning device according to any one of claims. 8. The rotational speed of the drive pulley of each belt drive system can be set independently, and both belts are driven in the same direction by synchronizing the feed speeds of their linear portions to drive the object to be cleaned. It is supplied to the cleaning area in a non-rotating state or is recovered from the cleaning area, or both belts are driven by non-synchronizing the feed speeds of their linear portions to supply the cleaning object while rotating the object to be cleaned or the cleaning area. 8. The ultra-precision cleaning device according to claim 7, wherein the object to be cleaned is rotated at a fixed position by recovering from the belt or driving both belts in the opposite directions by synchronizing the feed speeds of the linear portions thereof. 9. The wafer drive mechanism has a pair of arms, which are arranged in parallel with each other and are spaced apart from each other, and each of which has a pair of arms formed with a groove formed on an inner surface thereof so as to fit an edge portion of the object to be cleaned, inside each tip portion. Holding members are stretched in parallel with each other, the edges of the object to be cleaned are elastically held in the grooves of both holding members, and both arms are synchronized and driven in the same direction to wash the object to be cleaned. The ultra-precision cleaning device according to any one of claims 1 to 6, wherein the ultra-precision cleaning device is supplied to or recovered from the cleaning area.