JPH0938605A - Method for rinsing and drying substrate and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently assure the cleanliness on the surface of a substrate with a small amt. of the gas to be blown by regulating the fig velocity of high- purity gaseous flow and the rising speed of the substrate in such a manner that the liquid surface of a rinsing liquid is in contact with the substrate builds up in the leeward of the substrate. SOLUTION: The wafer 8 is set in a rinsing vessel and is subjected to final rinsing and, thereafter, ultrapure water is so supplied that the rinsing liquid is movable in a direction X over the entire part of the liquid surface 26 at the time of drying the wafer 8. The flow rate and flow velocity of the high- purity gas to be introduced from a piping 22 into the rinsing vessel, the temp. of a gas heater and the pulling up speed of the wafer 8 are respectively set. Such conditions under which liquid surface 26 forms the part 27 building up in the leeward of the wafer 8 at the time of pulling up the wafer 8, i.e., at the time the wafer 8 rises through and above the liquid surface 26 are determined. The wafer 8 is thereafter held by holding jigs 14 and is pulled up so as to be taken outside the rinsing vessel when the wafer 8 arrives at the prescribed position according to rising of the carrier 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for rinsing and drying a substrate for an electronic device requiring an ultraclean surface, and more particularly to a final rinsing and drying of a substrate after wet cleaning.

[0002]

2. Description of the Related Art Electronic industrial substrates such as semiconductor wafers and glass for liquid crystals require cleaning for sufficiently removing the adhesion of fine particles on the surface and chemical contamination in the device manufacturing process. Since liquid treatment is the most effective method for removing fine particles, so-called wet cleaning is usually an indispensable cleaning method. Originally, wet cleaning mainly uses chemicals to remove chemical pollutants. From the viewpoint of productivity, dozens of substrates are often placed in a carrier for cleaning, but large area of the substrate is required. Along with this, the processing of single-wafers is being attempted. After this chemical treatment, a rinse with ultrapure water is generally performed, and the cleaning process is completed by drying.

The degree of cleanliness of the substrate required in the electronic device manufacturing process is extremely high, and the degree of cleanliness must be sufficiently maintained even during drying. Particularly in the case of semiconductor devices, silicon wafers are required to have extremely strict cleanliness against fine particles and harmful metal impurities.
As a drying method that satisfies such requirements, two conventional methods have been mainly used.

One is a centrifugal drying method in which the carrier is rotated at a high speed so that the substrate surface becomes a rotating surface and the adhering water is blown off by centrifugal force. Another is an organic solvent with a hydrophilic substrate and a low latent heat of vaporization (usually isopropyl alcohol is used).
Is a vapor drying method in which the solvent is first condensed and dropped on a substrate to remove the adhering water by a solvent, and after dehydration, drying is performed by heating with a solvent vapor. The former is more productive,
Although it is desirable from the economical point of view, there is a risk of secondary contamination due to scattered mist and dust particles inside the equipment due to static electricity, and there is a risk of chipping at the wafer peripheral edge due to mechanical stress. However, it is disadvantageous for substrates that tend to have a larger diameter. The latter is advantageous in terms of re-contamination and mechanical stress because it does not operate at high speed and is less likely to generate static electricity, but it requires the use of a high-purity solvent, and therefore it is difficult to manage due to cost and management, as well as hydrophilic solvent vapor. There is a common fire risk problem. Further, since solvent molecules are adsorbed on the surface of the substrate, it cannot always be said that a clean surface is obtained.

Therefore, a drying method in which only water is used as a solvent and the wafer does not need to be operated at high speed has been attempted. As one of them, there is a method called a hot water pull-up method in which in order to accelerate the drying speed and lower the surface tension of the liquid, the substrate surface is gradually pulled up vertically from the hot water and the substrate is separated from the water surface and dried at the same time. In addition, the clean gas that has passed through a high-performance pleats-type dust removal filter such as a HEPA filter is heated and sprayed almost parallel to the vertical substrate surface that has been lifted from the rinse water. Then, there is a method called a hot air drying method in which this is evaporated and dried.

[0006]

The hot water pulling method is advantageous for drying a large-diameter substrate in that the mechanical stress on the wafer is small, and there is no problem in safety. However, although this method has some experience in the semiconductor field, it has hardly been put to practical use. It has weaknesses in terms of maintenance, such as weakness in vibration and difficulty in managing bubbles and particles in warm water.

In the hot water pulling method, in order to obtain a satisfactory clean surface with few fine particles, it is necessary to perform a rinse with warm ultrapure water with a sufficient amount of liquid for a sufficient time. However, after alkaline treatment such as ammonia-hydrogen peroxide cleaning, which is effective for removing fine particles, a trace amount of heavy metals, even though it is ultrapure water, is immersed in room temperature water in a wafer immersed in warm ultrapure water. The present inventor has found that it is easier to adsorb than the case. For example, when 0.1 ppb of Fe labeled with the radioactive isotope ⁵⁹ Fe is added to ultrapure water at 50 ° C. and the silicon wafer after alkali treatment is immersed for 10 minutes, the adsorption of Fe on the surface is 3 × 10 ¹⁰ atoms / It has been confirmed by the tracer method that it reaches cm ² . This amount cannot be ignored in the semiconductor device manufacturing process. Fe in ultrapure water can usually be controlled to 0.01 ppb or less,
The general purity standard for metal elements in ultrapure water production equipment is 0.1 pp
However, there is no guarantee that the Fe concentration will not deteriorate to about 0.1 ppb. Cu, Al, Zn, etc. in ultrapure water are F
It tends to be adsorbed on the silicon surface as much as or more than e. Thus, the immersion rinse with hot water is more likely to cause chemical contamination than room temperature water.

The method of removing water adhering to an object to be dried by blowing hot air is one of the most general methods for drying. However, this method is rarely used for drying semiconductor wafers. Even though semiconductors have very high requirements for cleanliness against fine particle contamination, the conventionally proposed hot air dryer uses quarter-micron level haze, which is called haze, even when a ULPA filter with higher performance than HEPA is used to remove gas dust. Ultrafine particles are frequently generated, and even contamination with a stripe pattern that is visible to the naked eye is likely to occur. Such pollution is reduced by increasing the speed of the hot air blown, but at least 8 to 1 is required to obtain this effect.
A wind speed of 0 m / sec is required. However, the HEPA filter was originally made for a clean room, and the optimum wind speed is 0.5.
It is about 1 m / sec. 8 digits faster than this
When a gas stream with a wind speed of 10 m / sec is passed for a long time, HE
Since the PA filter has a folding structure of thin fiber cloth, the reliability of dust removal is reduced. Further, such a filter structure may cause a leak when there is a sudden change in the wind pressure, and therefore, continuous use is required. If this happens, the amount of gas used will be enormous.

Further, according to the research conducted by the present inventor, even if the flow rate of hot air is 10 m / sec, unless the gas is high-purity nitrogen or oxygen derived from liquefied gas or air mixed with these, fine particles on the wafer surface are used. The level of can't be reduced to a satisfactory level. The atmosphere could not be used for ultra-clean hot air drying, no matter how high-performance filters were used to remove dust. Such a drying method that requires a large amount of highly clean gas is difficult to put into practical use in terms of economy.

Therefore, according to the present invention, the quality of the gas cleanliness and the method of spraying are used when the substrate to which the chemical is adhered, such as after chemical cleaning, is immersed in the liquid at room temperature and then sprayed with a gas to dry. It is an object of the present invention to provide a drying method and apparatus that can obtain a surface of sufficient cleanliness for the electronic industry even if the amount of gas sprayed is small. Normally, the surface that is well wetted by the rinse liquid is likely to be striped by hot air drying,
Particularly, it is possible to dry the substrate with good cleanliness for such a substrate.

[0011]

Means for Solving the Problems In order to achieve the above object, the present invention is to bring a substrate into contact with a rinse liquid, and then to bring the substrate from the liquid surface of the rinse liquid into the air in a state where the substrate surface is vertical. The surface of the rinsing liquid in contact with it in the leeward part of the substrate by gradually raising the surface of the substrate and spraying a high-purity gas flow parallel to the surface of the substrate and crawling over the liquid surface during the raising. There is provided a substrate drying method after rinsing, which comprises adjusting the flow rate of the high-purity gas flow and the rising speed of the substrate so that the substrate rises.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Substrate Examples of substrates to be dried in the present invention include semiconductors such as silicon and gallium arsenide, glass for liquid crystal devices, glass for photomasks, synthetic resins for circuit boards, etc. for the electronic industry. It includes those of the cleaning stage in the process of commercialization over the whole substrate.

[0013] as a rinse rinsing solution, ultrapure water is generally used. In the present invention, since it is necessary to raise the liquid level in the leeward portion of the substrate as described above, in the case of a substrate which is poorly wetted with water, an organic solvent having a small surface tension, such as isopropyl alcohol, methyl alcohol, acetone, dichloromethane or Freon. Among them, a solvent having a low boiling point, low toxicity, and nonflammability, such as dichloromethane, is preferable. Alternatively, the rinse ultrapure water is replaced with an organic solvent rinse solution before use. Specifically, for example, after rinsing with ultrapure water, the ultrapure water is once replaced with methanol, and then methanol is replaced with a dichloromethane rinse solution. Use of an organic solvent is generally disadvantageous in terms of economy, but by attaching a distillation purification device to the drying device used and circulating and using the organic solvent while distilling and refining it, economic difficulties are reduced. it can.

The purity of the rinsing liquid at the time of raising the substrate must be sufficiently purified to the extent that no harmful amount of residue or adsorption on the production of electronic devices is generated on the substrate. As far as ultrapure water is used, it can be used as long as it has a purity that satisfies the SEMI standard of 1986. But,
Since there is a possibility of contamination from the piping inside the device, it is desirable to inspect the residue on the highly clean substrate in advance for the purpose of checking the cleanliness of the environmental atmosphere during the use in order to evaporate and dry the droplets.

Substrate Raising and High-Purity Gas Flow According to the method of the present invention, the leeward portion of the substrate rising from the rinse liquid surface is adjusted by adjusting the substrate raising speed and the wind velocity of the high-purity gas flow. Make sure that the liquid surface rises. That is, the rising speed and the wind speed of the high-purity gas flow are controlled with the occurrence of this rise as an index. For example, when a standard silicon wafer with a diameter of 6 inches and a thickness of 650 μm is raised from ultrapure water, if the rise is too large, for example, 50 to 60 mm, If the surface is wet, it rises easily to cause surface contamination, and if it is too small, it becomes difficult to adjust the rising speed and the airflow velocity. Therefore 10-30
The degree of mm is preferable, and 10 to 20 mm is particularly preferable.

As the rinsing liquid, a solvent that wets the substrate is selected as described above, so if the pulling speed of the substrate is too fast or the velocity of the blowing airflow is too slow, the rise of the liquid surface becomes too large. The substrate is separated from the surface of the rinse liquid without being completely dried, and the drying is left to be naturally dried in the atmosphere. As a result, the cleanliness of the dried part is reduced. If the substrate is pulled up too fast, the fine particles in the rinse solution tend to remain on the substrate surface. This is because it is actually extremely difficult to completely remove the fine particles in the rinse liquid, and thus some fine particles are present, but most of these fine particles are present on the liquid surface due to surface tension. This is because the rinse liquid rises as a liquid film on the substrate surface due to the surface tension, and the liquid film also accompanies fine particles. However, in the present invention, since the pulling speed of the substrate is controlled as described above, there is no such inconvenience. On the other hand, if the pulling speed of the substrate is too slow, the productivity is lowered, which is not preferable.

In order to realize such an appropriate pulling rate, in the present invention, high-purity gas is sprayed so as to crawl on the liquid surface, and vaporization on the surface of the substrate that appears in the vapor phase after passing through the liquid surface is carried out. Facilitate. As the high-purity gas to be blown, it is practically possible to use high-purity nitrogen or oxygen from liquefied gas as a raw material, or air mixed with these. This is because, as mentioned above, since the rise of the liquid surface in the leeward portion of the substrate is used as an index for adjusting the flow velocity of the high-purity gas flow,
This is because the amount of the high-purity gas may be much smaller than that in the conventional hot air drying method. However, it is most preferable from the viewpoint of running cost to accelerate a part of the circulating clean air flow, which will be described later, and guide it as the high-purity gas flow for use.

If the high-purity gas stream blown onto the substrate is heated, the substrate can be dried more quickly, and the rise of the liquid surface at the leeward portion of the substrate becomes very small. The temperature of the gas flow is preferably room temperature to 200 ° C. depending on the type of rinse liquid. More specifically, when the rinse liquid is ultrapure water, 70 ° C. to 100 ° C. is preferable, and when the rinse liquid is a low boiling point highly volatile organic solvent such as dichloromethane, the room temperature to It is preferably the boiling point of the organic solvent.

When water having a large heat of vaporization is used as the rinse liquid, if the high-purity gas stream used for spraying is heated, a liquid film that crawls from the liquid surface onto the substrate even if the substrate pulling speed is increased. The height of can be minimized to a range that cannot be visually observed. According to the method of the present invention, the pulling speed of the substrate, the wind velocity of the high-purity gas flow, and the temperature thereof are optimized so that the rise of the liquid surface at the leeward side of the substrate occurs with an appropriate size. Can be easily performed visually.

Preferred Embodiments When the substrate after being dried by the method of the present invention is put into a step in which the adsorbed water remaining on the surface has a bad influence, for example, when it is put into a polycrystalline silicon film growing step. In order to ensure dehydration by drying, when the substrate is separated from the liquid surface, the substrate is continuously heated to, for example, 110 ° C.
It is effective to apply heating at 200 ° C.

Further, in the method of the present invention, it is desirable that the rinse liquid moves on the liquid surface in the direction of the high-purity gas flow. This is because in the method of simply overflowing the rinse liquid from the liquid tank, the liquid surface rises at the center of the rinse tank due to the surface tension, and the fine particles do not collect and overflow there, so that they easily adhere to the substrate to be pulled up. However, when the rinse liquid moves as described above, the fine particles on the liquid surface are flushed out, so that the concentration of the fine particles on the liquid surface is kept at the minimum level and the adhesion of the fine particles to the substrate is suppressed.

Further, in the method of the present invention, a flow rate is passed through a purification system comprising a filter for removing acidic gas, a filter for removing basic gas, an activated carbon filter for removing organic substances, and a dust removal filter. 0.2
It is preferably carried out in a stream of clean air circulating at ~ 2.0 m / sec.

As a filter for removing acid gas,
Pleated structure with low pressure loss made of anion-exchange fiber cloth or alkali-impregnated cloth impregnated with activated carbon, and as a filter for removing basic gas, cation-exchange fiber cloth or activated carbon impregnated with zinc chloride, etc. A pleated structure made of impregnated cloth, etc. with less pressure loss, an activated carbon filter for removing organic substances is made of activated carbon impregnated cloth or activated carbon fiber cloth, etc. with less pressure loss, and a dust removal filter is HEPA
Alternatively, a ULPA filter can be used. Since these filters with little pressure loss can be circulated and used in series, it is possible for each of the above gas molecules to produce a clean air flow of 0.1 ppb or less, and the present invention is most effective under such a clean environment. Exert. The reason is as follows.

A typical acid cleaning for making the surface of a silicon wafer hydrophilic is a hydrochloric acid / hydrogen peroxide cleaning agent (called SC-2, the standard composition is 1 volume of hydrochloric acid + 1 volume of hydrogen peroxide). +
Water 5 volume) and sulfuric acid / hydrogen peroxide detergent (standard composition is 1 volume sulfuric acid + 3 volume hydrogen peroxide). The present inventor washed the former hydrochloric acid with a cleaning agent labeled with a radioisotope ³⁶ Cl, then rinsed with ultrapure water of 18 MΩcm for 15 minutes and dried, and adsorbed on the surface from the amount of radioactivity remaining on the wafer. When the amount of hydrochloric acid was calculated, it was found that there were about 5 × 10 ¹⁴ molecules (30 ng) / cm ² . Also, with the latter detergent, when sulfuric acid was washed with a detergent labeled with ³⁵ S of radioisotope and rinsed with ultrapure water in the same manner, it was found that the adsorption power was 10 ¹⁴ molecules (20 ng) / cm ² or more. It was Ammonia / hydrogen peroxide cleaner (SC-1), which produces a strongly hydrophilic surface with a typical alkaline cleaner, has a standard composition of 1 volume of ammonia + 1 volume of hydrogen peroxide + 5 volumes of water. ) Even 10 ¹⁴ molecules (10 ng) / cm ²
It was found by ultra-pure water elution / ion chromatography analysis that the above adsorption occurred. On the other hand, in a clean room of a normal semiconductor factory, fine particles are thoroughly cleaned, but depending on the location, acidic molecules such as sulfuric acid, hydrochloric acid, and nitrogen dioxide reach several tens of ppb, and ammonia and Alkaline molecules such as amines can reach dozens of ppb to over 100 ppb in some places. Also, the number of organic molecules reaches several tens of ppb. That is, such a molecule is present in several tens to one hundred and several tens ng in 1 L of air in the atmosphere. Therefore, if hot-air drying is performed on the substrate after the above-described rinsing in such an atmosphere, the molecules in the hot-air very easily dissolve into the liquid film on the substrate immediately before drying, and the acid or ammonia remaining on the surface is removed. Also reacts. As the liquid dries, this solute crystallizes on the surface as salt fine particles.
Some organic substances in the atmosphere may adsorb such fine particles as nuclei, and the fine particles become larger.
Wafer-like contamination, called haze, is a collection of ultrafine particles at the quarter micron level. Assuming that such fine particles are spheres having a specific gravity of 2 and a diameter of 0.1 μm, the weight thereof is 10 ⁻⁶ ng. Therefore, it is considered that a large amount of fine particle groups are generated by the mechanism as described above and this haze is generated.

Using a chemical filter as described above,
Since the drying is performed in an atmosphere in which molecules of acid, alkali, and organic substances are removed to 0.1 ppb or less, or in a high-purity gas of the same level made from liquefied gas, salt crystallization by the above-mentioned reaction occurs. It won't happen. Therefore, a clean surface substrate having a low particle concentration can be obtained.

Apparatus The above-described rinsing and drying method of the present invention includes, for example, means for bringing the substrate into contact with the rinse liquid, holding the substrate in a state where the substrate surface is vertical, and removing the rinse liquid from the liquid surface. Means for gradually raising into the gas phase, means for spraying a high-purity gas stream parallel to the substrate surface and raising the surface of the rinse liquid when raising the substrate, and further, at least the above, Performed by an apparatus for rinsing and drying the substrate, which has a container means for isolating the vapor phase on the liquid surface, which is brought into contact with the pulled-up substrate, from the external environment, and which supplies a purified gas to the vapor phase. be able to. The apparatus may further include a transport means for receiving the dried substrate and unloading it to the outside of the apparatus, and / or a means for gripping the transported substrate and loading it on a required transport carrier.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method and apparatus of the present invention will be described in detail below with reference to the accompanying drawings. All the examples show the case of single-wafer treatment. The first embodiment is also applicable to a batch type in which a plurality of substrates are processed, but the drawing is complicated only by changing the substrate holding device for a plurality of substrates, and its structure is not related to the essence of the present invention. This is because Examples 2 and 3 are dedicated to single-wafer processing. In the following, a vertical cross-sectional view seen from a direction perpendicular to the substrate surface will be called a front cross-sectional view, and a vertical cross-sectional view seen from a direction parallel to the substrate surface will be called a side cross-sectional view. Further, in order to facilitate the description of the moving direction of the substrate, the direction of the high-purity gas flow is X, the opposite direction is X ', the frontward direction perpendicular to the substrate surface is Y, the opposite direction is Y', and the upward direction. Is Z, and the direction is Z '.

Embodiment 1 FIG. 1 shows an example of the rinsing / drying apparatus of the present invention. A silicon wafer stored in ultrapure water after finishing a chemical solution treatment such as SC-1 treatment of a standard composition to obtain a hydrophilic surface and further rinsing with ultrapure water is finally rinsed with this device. And the example which dried is demonstrated. FIG.
(B) is a front sectional view of the device, and FIG. 1 (a) shows the direction in FIG. 1 (a). FIG. 2B is a side sectional view of the device as viewed in the X ′ direction from the X side in FIG. 1B, and FIG. 2A shows the direction in the device. An automatic mechanism is preferable for loading the wafer into the apparatus, but it may be manually operated.

This apparatus is provided with a quartz glass square tank 1 as a means for bringing the substrate into contact with the rinse liquid, that is, a rinse means. This is suitable for processing a large number of wafers at the same time, that is, for batch processing, in which the immersed wafer moves over the overflowing liquid surface to the upper vapor phase and is dried in the process. . The liquid is supplied from the bottom of the tank, and an auxiliary liquid supply port is provided near the liquid surface so that the liquid surface can quietly flow along the substrate surface.

More specifically, each tank is a tank that fills the ultrapure water 2 for performing the final overflow rinse, and a part of the side wall 3 on one side is slightly cut so that the ultrapure water flows only from there. It is made to overflow. The tank 1 has a first supply means 4 of ultrapure water at the bottom, and the liquid flows in the direction X over the entire surface of the rinse liquid 2 on the upper side of the side wall 5 facing the side wall 3 (just below the upper end). Thus, there is the second ultrapure water supply means 6. In this embodiment, the first ultrapure water supply means 4 is a pipe which is introduced from the outside of the tank 1 and has holes 7 formed at equal intervals in the upper portion thereof. It is composed of an open pipe joined to the upper part of the.

The rinsed wafer is carried into the tank 1, but the carrying-in means is not shown. Such a loading mechanism needs to be an automatic mechanism. Wafer 6
In this embodiment, a carrier 9 for loading the wafer 8 is provided as a means for holding the wafer so that its surface is vertical and lifting it from the rinse liquid. The carrier 9 is a wafer 8
It comprises a grip portion 10 for holding the so that its surface is vertical and a handle 11 for supporting it. The end 11a of the handle 11 is connected to a column 13 that is vertically driven by a vertical movement drive mechanism 12. The carrier 9 can be optionally raised and lowered by the vertical movement drive mechanism 12. This device includes:
Means for receiving and carrying the wafer 8 pulled up in the Z direction by the vertical movement drive mechanism 12 from the carrier 9 is provided. The means is a sandwiching jig 14 and a driving mechanism 15 therefor.
(Omitted in FIG. 1B). In this embodiment, the jig 14 has a nipping surface 16 which is curved in an arc shape and conforms to the circumference of the disk-shaped wafer 8, and holds the wafer 8 by nipping it, and further holds the wafer 8 in the Z and Z'directions and the X direction. Direction and X'direction can be freely moved.

Above the quartz glass tank 1, there is provided a hood 17 whose walls are made of quartz glass plates on all four sides and whose upper and lower parts are open. The four side walls of the hood 17 are approximately at the upper ends of the side walls of the quartz tank 1. It is joined. Furthermore, handle 11 of carrier 9
A slit 18 is provided on the side wall in the Y'direction so that the support column 13 for supporting the wafer can be vertically moved up and down by the power of the movement drive mechanism 12, and a slit 19 is provided so that the wafer gripping means 14 can similarly be vertically moved. Is provided on the side wall in the direction. Further, by means of 15, a hole 20 is opened on the side wall in the X direction so that the sandwiching jig 14 holding the wafer can take out the wafer from the hood 17, and is closed by a window cover 21 made of a fluororesin when unnecessary. Has been done.

The means for spraying the high-purity gas flow is, for example,
A gas outlet is provided at a position slightly higher than the liquid surface in a direction parallel to the substrate surface and facing upwind. It is desirable to provide a vertically long slit at the blowout port so that the blown out gas flow becomes a laminar flow. With such blowing means,
A thick laminar flow along the surface of the substrate can be generated to crawl over the liquid surface. In the case of this embodiment, the quartz hood 17
A glass pipe 22 is connected to and opened at the bottom of the side wall in the X'direction of the gas outlet 23 to introduce a high-purity gas flow.
Is provided, and an exhaust port 24 for the gas flow is opened at a position opposite to the gas outlet on the side wall in the X direction, that is, a cover 25 for the exhaust port is provided. The outlet 2
3 has a plurality of vertical slits 2 to make the air flow laminar.
3a is provided.

All of the above mechanisms are housed in an air-return type clean booth equipped with the following filter groups. That is, above the upper opening of the hood 17, K
A cloth filter containing activated carbon impregnated with I and KOH, a pleated cation exchange fiber cloth filter and a cloth filter containing pleated activated carbon are stacked in this order from the top, and the air from which gaseous impurities have been removed is placed under the filter. And is supplied to the ULPA filter 26 for removing fine particles. The air that has passed through these filters flows through the inside and outside of the above mechanism in the closed space in the clean booth, and then most of it returns to the filter group.

After the apparatus was constructed in this way, the air in the apparatus was analyzed by the Impinger ion chromatography method. Cl, SO ₂ , NO ₂ , SO ₄ and NH ₃ are all 0.1 ppb or less, and the contact angle of water droplets hardly changes after leaving the hydrophilic wafer in the equipment for 24 hours, which is harmful. The equipment was put into operation after confirming that the organic matter was at a harmless level.

A quartz glass gas heater (not shown) having a double tube structure is directly fused to the pipe 22 forming the gas outlet 23. The gas heater has a double tube structure made of quartz glass, and a heating element is contained in the inner tube to heat the gas passing between the inner tube and the outer tube. High-purity nitrogen for semiconductor device manufacture, which has passed through a precision ceramic dust filter for 0.01 μm size, can be introduced into the hood from the gas outlet 23 after heating with a gas heater. The gas blown out in this way flows parallel to the surface of the wafer 8, that is, along the liquid surface in the X direction.

An example of wafer drying by this apparatus will be shown below. After the wafer is set in the rinsing tank 1 as shown in FIG. 1A and the final rinsing is performed, the ultrapure water is rinsed from the second ultrapure water supply means 6 over the entire liquid surface.
Supply so that it can be visually confirmed to move in the direction. After this, with the numerical value confirmed in the preliminary wafer pull-up test,
Gas flow (put a flow meter in front of the filter),
The temperature of the gas heater and the wafer pulling speed are set. Wafers cleaned by the same method when pulling a preliminary wafer,
In this case, a SC-1 treated wafer is used, and when the wafer is pulled up, that is, when the wafer rises above the liquid surface,
As shown in (b), the liquid level 26 is 2 at the leeward part of the wafer.
Find a condition that makes you excited like 7. A standard composition SC of a P (100) wafer with a diameter of 6 inches and a thickness of 650 μm is used.
With respect to a wafer that has been cleaned at 70 ° C. for 10 minutes under standard conditions of −1, in this device, if the heater set temperature of the gas heater is 300 ° C. and the nitrogen is 30 L / min, the pulling rate is 5 to 13 cm. A favorable rise was obtained at / min.
Therefore, the pulling speed was set to 10 cm / min and the heater temperature was set to 30 cm.
The temperature was 0 ° C. and the gas flow rate was 30 L / min. In this case, the gas temperature at the outlet 23 was 90 ° C.

At the same time when the wafer pulling is started, the driving mechanism 15 is operated to open the wafer holding jig 14 and lower it to the lowest position (the position of the virtual line 14a). When the center of the wafer reaches the midpoint between the two sandwiching tools, the lifting of the wafer carrier 9 is stopped and the drive mechanism 1 is immediately stopped.
5 is moved to sandwich the edge of the already dried wafer 8a with the sandwiching jig 14, and pulling is continuously performed at the same speed as the carrier rising speed. When the wafer leaves the liquid surface, the ascent is stopped for 20 seconds, the water droplets occasionally remaining on the lower end of the wafer are surely dried, and then the jig 14 is moved to the highest position (the jig 14 is shown by a solid line and the wafer is shown by an imaginary line 8a). Position). By opening the window 21 and moving the jig 14 in the X direction, the dried wafer can be taken out.

The thus dried wafer was compared with a wafer surface (comparative example) which was similarly SC-1 washed and then centrifugally dried in a conventional type clean room equipped only with an ULPA filter. The oblique test in the dark room showed no significant difference between the two in terms of haze and particle concentration. Further, as a result of immersing the wafer of this comparative example in ultrapure water and performing an ion chromatographic analysis of the solution, SO ₄ ions on the wafer surface were 3 × 10 ¹³ / c.
m ² and Cl ions were detected at 5 × 10 ¹² / cm ^2, and when this solution was analyzed by a TOC (total organic carbon) measuring device, 100 ng / cm ² or more was detected, whereas In the example wafer, detection limit is 5 for any ion
× 10 ¹¹ / cm ² or less, and TOC detection limit 1
It was 0 ng / cm ² or less.

Example 2 As the diameter of the Si wafer is increased from 8 inches to 12 inches, and further to 16 inches, cleaning is inevitably single-wafer. As a matter of course, the single-wafer is also preferable for the drying, and therefore, the mechanism dedicated to the single-wafer is provided in this embodiment. In this case as well, the mechanism for receiving the wafer is the same as that in the first embodiment, and therefore the description of this mechanism and its operation will be omitted. Therefore, the description mainly depends on how the liquid level and the rising of the wafer are configured. Therefore, a side sectional view of this portion is shown in FIG. 3 (b), and a plan view from above is shown in FIG. 5 (b). The directions in each case are shown in FIG. 4 (a) and FIG. 5 (a).

A slit-shaped opening 42 through which the wafer 8 can pass is formed at the center of the bottom of a quartz glass square tank 41 having a depth of 20 mm.
And a plurality of ultrapure water supply ports 43 for rinsing are provided at the bottom of the quartz tank.
To combine. The wafer 8 is rinsed with the ultrapure water 49.

After the wafer 8 is put into the carrier 45 and the chemical solution treatment and the rinsing are completed, the vertically expandable column 47 connected to the mechanism 46 for vertically moving the carrier 45 (at the lowest position at the start). Place on top and secure.
In the X'direction, a gas outlet 48 that creates a gas flow that crawls on the liquid surface
Is provided. A high-purity gas stream 50 parallel to the wafer 8 is blown out from the outlet 48.

Except for those described here, the sandwiching jig and its driving mechanism, the air circulation system, and the gas heating / filtering mechanism are all the same as those in the first embodiment. However, an air blower was installed in front of the ceramic filter to take in the air directly below the ULPA filter and send it to the air outlet. At this time, a small water droplet was placed on the clean wafer, and a test was conducted to dry it within 1 minute with this heated gas, and it was confirmed in advance that no residue remained.

An example of rinsing and drying by this mechanism will be shown below. After cleaning the wafer with standard composition SC-2 at 70 ° C. for 10 minutes and rinsing with ultrapure water for 10 minutes on the support 47, ultrapure water was introduced from all supply ports 43,
The ultrapure water 48 in the quartz tank is allowed to slightly and almost uniformly overflow from the edge. If the width of the slit 42 is 3 mm and the wafer is 8 inches, the total amount of ultrapure water introduced from all supply ports may be about 5 L / min. The liquid surface is kept almost horizontal,
Most of the ultrapure water supplied falls from the slit 42,
It flows along the hydrophilic wafer surface and the final rinse proceeds.

As in the first embodiment, hot air is made to flow from the air outlet 48 to the liquid surface under the condition that the liquid can rise in the downstream portion of the wafer surface, and the wafer is pulled up. After the wafer leaves the liquid surface, the same procedure as in Example 1 is performed. When the rinsed and dried wafer surface was compared with the rinsed and dried wafer surface in Example 1 and the haze and fine particle concentration by oblique light inspection in a dark room, both were clearly inferior to those in Example 1. Was there. So 1M
An ultrapure water shower nozzle to which Hz ultrasonic waves were added was provided below the bottom of the quartz glass tank, and a cleaning treatment was added for 2 minutes before the final rinse. .

Next, by the same surface analysis as in Example 1,
The NH ₃ ion was compared between the wafer surface that was centrifugally dried in a conventional type clean room after SC-2 cleaning and that of this example. 5 × 10 ^{12 for} centrifugally dried wafers
/ Cm ² was detected, but in this embodiment, the detection limit was 5
It was × 10 ¹¹ / cm ² or less.

Example 3 As an example in the case where surface adsorption of water is not desirable, a TFT of a flat panel display in which the chlorofluorocarbon cleaning is most effective
At the time of cleaning before applying polyimide in the cell process, the following cleaning was performed instead of Freon. FIG. 6B is a bird's-eye view from above of the rinse means of the used apparatus.
(A) shows the direction in it. The quartz glass pipes 61 and 62 whose both ends are sealed have liquid ejection holes 63 in a row on the sides facing each other, and a liquid supply pipe 64 is connected to each of them.
Liquid is introduced as indicated at 6. The TFT substrate 67 was allowed to pass from below between the rows of ejection holes facing each other at a distance of several mm from the ejection holes. Further, the gas outlet 65 is installed in the X ′ direction.

The polyimide pre-coated substrate immediately before flon cleaning was set to a large size similar to the vertical mechanism of the previous Example 46, and was positioned below the center of the gap of the quartz tube. As a supply liquid, a non-flammable dichloromethane distillate that had been microfiltered was used, and it was made to flow out from a jet port to rinse the substrate and start the rise of the substrate. When the upper surface of the substrate reaches the position of the quartz tube,
The jet flow is slightly wavy, but creates a substantially horizontal liquid surface with the substrate surface. At this point, high-purity nitrogen at room temperature is blown from the blow-out port at 5
The flow rate was 0 L / min, and the substrate was raised while adjusting the rising speed so that a slight rise was observed on the leeward side of the substrate. Since this example was a preliminary experiment, at the final stage of raising, the substrate was clamped and supported manually and pulled up.
The product thus dried was subjected to the steps after the polyimide coating, and the white spots, black spots, image unevenness, and the like were compared with the chlorofluorocarbon-cleaned product, but there was almost no difference.

[0049]

According to the present invention, since mechanical stress is not applied, there is little risk of damage. Since the liquid used is at room temperature and the flow rate of the high-purity gas is relatively low, it is economical and the maintenance of the device is easy. Moreover, there is no danger of vapor cleaning of flammable organic solvent. In addition to a low level of particulate deposition comparable to the conventional major drying methods, the level of surface organics and non-metal ion contamination can be significantly reduced compared to the prior art. Therefore, it is possible to meet the trend of increasing the sophistication of electronic devices and increasing the area of substrates, and it is highly practical.

[Brief description of drawings]

FIG. 1 (a) shows a direction in (b), and (b) is a front sectional view of an apparatus of the present invention.

FIG. 2 (a) shows the direction in (b), and (b) is a side sectional view of the same device.

FIG. 3A is a view showing a direction in FIG. 3B, and FIG. 3B is an explanatory view showing a rising state of a wafer and a liquid surface which are bidding from the rinse liquid surface.

FIG. 4A is a front sectional view showing a direction in FIG. 4B, and FIG. 4B is a front view showing a state in which a wafer in another apparatus of the present invention is brought into contact with a rinse liquid and bid up from the rinse liquid.

5 (a) shows the direction in (b), and FIG. 5 (b) is a side sectional view of a part of the same device as in FIG.

FIG. 6 (a) shows a direction in (b), and FIG. 6 (b) is a plan view of a means for bringing a wafer into contact with a rinse liquid in another apparatus of the present invention.

[Explanation of symbols]

 1 Quartz Glass Square Tank 2 Ultrapure Water 6 Second Ultrapure Water Supply Means 8 Wafer 12 Vertical Movement Drive Mechanism 14 Clamping Jig 15 Drive Mechanism 17 Hood 23 Gas Blowout Port 24 Exhaust Port 26 ULPA Filter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Noriyuki Saito, 3-7-1, Nishishinbashi, Minato-ku, Tokyo Toshiba Plant Construction Co., Ltd. (72) Naomi Kato, 3-7 Nishishinbashi, Minato-ku, Tokyo No. 1 in Toshiba Plant Construction Co., Ltd. (72) Inventor Mitsunobu Masuda 1-32, Dojimahama, Kita-ku, Osaka-shi, Osaka Prefecture No. 23 Takuma Co., Ltd. (72) Naoki Irie 1-chome, Dojimahama, Kita-ku, Osaka-shi, Osaka 3-23 No. 23 Takuma Co., Ltd. (72) Inventor Yuji Fukasawa No. 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Incorporated Corporate Research and Development Center, Toshiba (72) Inventor Hisashi Muraoka 3 Mihigaoka, Aoba-ku, Yokohama, Kanagawa -15-2

Claims (8)

[Claims] 1. A substrate is brought into contact with a rinsing liquid, and then the substrate is gradually raised from the liquid surface of the rinsing liquid into the vapor phase with the substrate surface vertical, and the substrate surface is raised during the raising. In a method of rinsing and drying a substrate in which a high-purity gas stream is sprayed in parallel and along the liquid surface, the flow rate of the high-purity gas stream so that the liquid surface of the rinse liquid in contact with it in the leeward portion of the substrate rises. A method for drying a substrate after rinsing, which comprises adjusting the rising speed of the substrate. 2. The method according to claim 1, wherein the substrate comprises a semiconductor wafer, glass for liquid crystal devices, glass for photomasks, and synthetic resin plate for circuit boards. 3. A filter for removing an acidic gas, a filter for removing a basic gas, an activated carbon filter for removing an organic substance, and a dust remover for lifting the substrate from the rinse liquid and spraying a high-purity gas flow. Flow rate of 0.2-2.0m through a purification system equipped with a filter for
1) performed in a clean air stream circulating at 1 / sec.
Or the second method. 4. The high purity gas stream is heated.
The method according to claim 1. 5. The method of claim 3 wherein said high purity gas stream is introduced by accelerating a portion of said circulating clean air stream. 6. The method according to claim 1, further comprising heating after the substrate is completely pulled up from the surface of the rinse liquid. 7. A means for bringing a substrate into contact with a rinse liquid, a means for holding the substrate in a state where the surface of the substrate is vertical and gradually rising from the liquid surface of the rinse liquid into the vapor phase, A means capable of spraying a high-purity gas stream parallel to the substrate surface at the time of raising and so as to crawl on the liquid surface of the rinse liquid, and further, at least on the liquid surface, the pulled substrate is in contact with A device for rinsing and drying a substrate, which has a container means for isolating the vapor phase from the external environment and supplying a purified gas to the vapor phase. 8. A purification system in which the container means includes a filter for removing an acidic gas, a filter for removing a basic gas, an activated carbon filter for removing organic substances, and a dust removal filter inside the container means. The apparatus according to claim 7, further comprising: a clean air flow passing through the system and circulating at a flow rate of 0.2 to 2.0 m / sec, to the gas phase in the container.