JP2000223466A - Method and system for drying wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a system for drying a wafer in which drying efficiency can be enhanced while shortening the drying time. SOLUTION: Nitrogen gas is ejected into a space above the liquid level of pure water in a drying chamber where a wafer is immersed and, at the same time, liquid-phase isopropyl alcohol is ejected at a temperature higher than that of the wafer in the vicinity of an opening for ejecting nitrogen gas thus spraying mist-like IPA(isopropyl alcohol) into the space. When the wafer is exposed from the liquid level of pure water in the drying chamber, pure water adhering to the opposite sides of the wafer is substituted by mist-like IPA and evaporated thus drying the wafer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer drying apparatus and method for drying a wafer surface without contacting oxygen when a wafer immersed in pure water is taken out of the pure water.

[0002]

2. Description of the Related Art Conventionally, in a drying apparatus disclosed in Japanese Patent Publication No. 6-103686, nitrogen gas is used as a carrier and IPA (isopropyl alcohol) is used as a vapor.
The wafer is supplied into an upper space in a wafer processing tank which is treated with an etching treatment liquid and then washed with pure water. Then, the pure water in the processing tank is drained to expose the wafer in the processing tank, and the IPA vapor supplied to the upper space of the processing tank is replaced with water droplets adhering to the exposed surface of the wafer, thereby removing the wafer surface. Is allowed to dry without touching oxygen and naturally oxidizing.

[0003]

However, in the above-mentioned structure, the same temperature as the normal temperature of the wafer, that is, the normal temperature IPA vapor is supplied into the processing tank to be replaced. There is a problem that the drying time until the surface of the wafer evaporates and the surface of the wafer dries becomes longer, and the drying efficiency is poor. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, and to replace water droplets attached to the surface of a wafer with a mist-like IPA at a temperature higher than the temperature of the wafer, so that the IPA can be removed from the surface of the wafer. It is an object of the present invention to provide a wafer drying apparatus and method which can dry quickly, shorten the drying time, and increase the drying efficiency.

[0004]

In order to achieve the above object, the present invention is configured as follows. According to the first aspect of the present invention, a drying chamber in which a wafer can be immersed in pure water, and nitrogen gas is injected into a space above the liquid surface of the pure water in the drying chamber, and simultaneously a liquid phase isopropyl alcohol And a mist spraying device for spraying mist-like isopropyl alcohol into the space at a temperature higher than the temperature of the wafer and near the spray opening of the nitrogen gas, and discharging the pure water from the drying chamber. Or by raising the wafer in the drying chamber, when the wafer is exposed above the liquid level from the pure water in the drying chamber, the pure water adhering to the front and back surfaces of the wafer becomes mist-like. The isopropyl alcohol is replaced by the isopropyl alcohol, and thereafter, the isopropyl alcohol is evaporated from both the front and back surfaces of the wafer to be dried. To provide a wafer drying apparatus that.

According to a second aspect of the present invention, the mist of isopropyl alcohol is sprayed at a temperature at least 5 ° C. higher than the temperature of the wafer and in the vicinity of the nitrogen gas spray opening. The wafer drying apparatus according to the first aspect, in which the wafer is sprayed into the space, is provided.

According to a third aspect of the present invention, there is provided the wafer drying apparatus according to the first or second aspect, wherein the wafer is at room temperature and the mist is approximately 30 ° C. or higher.

According to a fourth aspect of the present invention, the mist-like isopropyl alcohol is in any one of the first to third aspects wherein the isopropyl alcohol itself is floating alone in the nitrogen gas. 3. A wafer drying apparatus according to item 1.

According to a fifth aspect of the present invention, the isopropyl alcohol is sprayed in a mist at a temperature higher by 5 ° C. to 60 ° C. than the temperature of the wafer.
The present invention provides a wafer drying apparatus according to any one of the above aspects.

According to a sixth aspect of the present invention, a wafer is immersed in pure water in a drying chamber, and nitrogen gas is injected into a space above the liquid level of the pure water in the drying chamber. Is sprayed at a temperature higher than the temperature of the wafer and in the vicinity of the nitrogen gas injection opening to spray mist-like isopropyl alcohol into the space, and then discharge the pure water from the drying chamber. Or by raising the wafer in the drying chamber,
When the wafer is exposed above the liquid level from the pure water in the drying chamber, the pure water attached to both the front and back surfaces of the wafer is replaced by the mist-like isopropyl alcohol, and then from both the front and back surfaces of the wafer. A method for drying a wafer, characterized in that the isopropyl alcohol is dried by evaporation.

According to a seventh aspect of the present invention, the liquid isopropyl alcohol is injected at a temperature at least 5 ° C. higher than the temperature of the wafer and near the injection opening of the nitrogen gas to remove mist-like isopropyl alcohol. A wafer drying method according to a sixth aspect, wherein the wafer is sprayed into the space.

According to an eighth aspect of the present invention, there is provided the wafer drying method according to the sixth or seventh aspect, wherein the wafer is at room temperature, and the mist is approximately 30 ° C. or higher.

[0012] According to a ninth aspect of the present invention, the mist-like isopropyl alcohol is any one of the sixth to eighth aspects, wherein the isopropyl alcohol itself is floating alone in the nitrogen gas. The method for drying a wafer according to the item 1 is provided.

According to a tenth aspect of the present invention, the isopropyl alcohol is sprayed in a mist at a temperature higher by 5 ° C. to 60 ° C. than the temperature of the wafer. A method for drying a wafer is provided.

According to an eleventh aspect of the present invention, the mist spraying device includes a first injection hole for injecting the nitrogen gas,
A second injection hole that is disposed near the injection hole and injects the liquid phase isopropyl alcohol;
Inject the nitrogen gas from the injection hole and simultaneously
The wafer drying apparatus according to any one of the first to fifth aspects, wherein the mist-like isopropyl alcohol is sprayed into the space by spraying the liquid-phase isopropyl alcohol from a spray hole.

According to a twelfth aspect of the present invention, the mist spraying device includes a first passage for supplying the nitrogen gas to a rectangular solid body made of a porous fluororesin having high water repellency; A second passage disposed closer to the wafer-facing surface of the main body than the passage and for supplying the liquid-phase isopropyl alcohol; supplying the nitrogen gas to the first passage and simultaneously supplying the liquid to the second passage. Isopropyl alcohol in a liquid phase is supplied and the liquid phase isopropyl alcohol is sprayed together with the nitrogen gas from the wafer facing surface of the porous rectangular parallelepiped main body to spray the mist-shaped isopropyl alcohol into the space. The wafer drying apparatus according to any one of the first to fifth aspects is provided. According to a thirteenth aspect of the present invention, the temperature of the wafer is equal to or higher than the temperature of the wafer and is 60 ° C.
The wafer drying apparatus according to any one of the first to fifth, eleventh, and twelfth aspects, wherein the nitrogen gas is injected at a high temperature in a range up to and including: According to a fourteenth aspect of the present invention, the nitrogen gas is injected at a temperature higher than the temperature of the wafer by 5 ° C. to 60 ° C.
, A wafer drying apparatus according to any one of aspects 5, 11, and 12. According to a fifteenth aspect of the present invention, there is provided the sixth to tenth aspects, wherein the nitrogen gas is injected at a high temperature equal to or higher than the temperature of the wafer or up to 60 ° C. over the temperature of the wafer. A method for drying a wafer according to any one of the aspects is provided. According to a sixteenth aspect of the present invention, the wafer drying method according to any one of the sixth to tenth aspects, wherein the nitrogen gas is injected at a temperature higher than the temperature of the wafer by 5 ° C. to 60 ° C. Provide a way. According to another aspect of the present invention, the mist spraying device uses a liquid phase IP by electric energy such as ultrasonic waves.
Instead of atomizing A, without using electric energy, nitrogen gas is injected into a space above the liquid surface of the pure water in the drying chamber, and at the same time, isopropyl alcohol in the liquid phase is applied to the wafer. The first to fifth and eleventh to fourteenth aspects, in which mist-like isopropyl alcohol is sprayed into the space by spraying at a temperature higher than the temperature and near the spray opening of the nitrogen gas. The described wafer drying apparatus can also be provided. According to another aspect of the present invention, the mist spraying device is arranged in a pair, and the pair of mist spraying devices is opposed to each other in a space above the level of the pure water in the drying chamber. Spraying isopropyl alcohol into the space, or the mist spraying device is arranged in a pair,
The pair of mist sprayers sprays the mist-like isopropyl alcohol downward in the space above the pure water level in the drying chamber toward the pure water level in the space, The wafer drying apparatus according to the aspect can also be provided. According to still another aspect of the present invention, when spraying the mist, instead of using liquid energy IPA to mist by electric energy such as ultrasonic waves, without using electric energy, At the same time, a nitrogen gas is injected into a space above the liquid surface of the pure water in the drying chamber, and simultaneously, isopropyl alcohol in a liquid phase is injected at a temperature higher than the temperature of the wafer and near the injection opening of the nitrogen gas to form a mist. It is also possible to provide the wafer drying method according to any one of the sixth to tenth and fifteenth to sixteenth aspects, wherein the isopropyl alcohol is sprayed into the space. According to still another aspect of the present invention, when the mist is sprayed, the mist-like isopropyl alcohol is sprayed into the space from opposite sides in a space above the liquid level of the pure water in the drying chamber. Or, in any of the above aspects, the mist-like isopropyl alcohol is sprayed downward in the space above the pure water level in the drying chamber toward the pure water level in the space. The described wafer drying method can also be provided.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, the wafer drying apparatus according to the first embodiment of the present invention immerses the wafer 2 in pure water 40 for cleaning the wafer 2 supported by a known carrier (not shown). At the same time that nitrogen gas is injected into the drying chamber 1 that can be dried after washing and the space 4 on the liquid surface of the pure water 40 in the drying chamber 1, liquid-phase isopropyl alcohol (hereinafter simply referred to as IPA). ) At a temperature higher than the temperature of the wafer 2 (for example, room temperature), preferably higher than the temperature of the wafer 2 by at least 5 ° C., more preferably higher than the temperature of the wafer 2 in the range of 5 ° C. to 60 ° C. A mist spraying device 3 for spraying mist-like IPA into the space 4 to discharge the pure water 40 in the drying chamber 1 or to raise the wafer 2 in the drying chamber 1 thing When the wafer 2 is exposed above the liquid level from the pure water 40 in the drying chamber 1, the mist spraying devices 3 and 3 apply IPA to the front and back surfaces of the wafer 2 in a mist state, that is, transfer nitrogen to the carrier. Instead, the IPA itself is continuously sprayed in a state of being suspended in the nitrogen gas alone, so that the pure water 40 attached to the front and back surfaces of the wafer 2 is replaced by the mist-like IPA. I have to.

Each of the mist spraying devices 3 is shown in FIG.
As shown in (B), a nitrogen gas passage 3a and a liquid phase IPA passage 3c are formed in a rectangular parallelepiped main body made of a fluororesin so as to penetrate along the longitudinal direction. And a narrow nitrogen gas ejection passage having an ejection hole 3e extending from the opening 2 and opened substantially toward the wafer 2 (specifically, toward the space between the adjacent wafers 2 and 2 and corresponding to the center of the wafer 2). 3b and a plurality of nitrogen gas ejection passages 3 extending from the IPA passages 3c.
injection hole 3f opened toward injection hole 3e at the open end of b
Are provided with a large number of thin IPA ejection passages 3d. Therefore, the nitrogen gas is injected from the injection holes 3e of the nitrogen gas injection passage 3b, and at the same time, the injection holes 3d of the IPA injection passage 3d.
The mist-like IPA can be sprayed into the space 4 by injecting the liquid phase IPA from f. The injection holes 3e of the nitrogen gas ejection passage 3b and the injection holes 3f of the IPA ejection passage 3d constitute a set of mist spray nozzles, and each set of mist spray nozzles is arranged at a predetermined interval. In addition, for example, about 50 wafers 2,..., 2 are disposed so as to face the space between adjacent wafers 2 and 2, and mist spray nozzles are also provided outside the wafers 2 at both ends in the drying chamber 1. By arranging, the mist of the IPA can be sprayed from the mist spray nozzle onto both the front and back surfaces of all the wafers 2.

On the other hand, the nitrogen gas may be used at room temperature or on the wafer 2.
Or at a temperature higher than room temperature (for example, room temperature or a high temperature ranging from the temperature of the wafer 2 to 60 ° C.), preferably at least 5 ° C. or higher than room temperature or the temperature of the wafer 2 It is supplied at a high temperature, more preferably at a normal temperature or a temperature higher than the temperature of the wafer 2 by 5 ° C. to 60 ° C.
The mist sprayers 3 and 3 arranged on the left and right in FIG. 1 are supplied via manual valves 20 and 21, respectively. It is preferable that the first air operated valve 18 automatically adjusts the flow rate of the nitrogen gas based on the flow rate of the nitrogen gas detected by the flow meter 19. The manual valves 20 and 21 are disposed in the left and right mist spraying devices 3 and 3 respectively, and by manually adjusting the degree of opening and closing of the manual valves 20 and 21, the left and right mist spraying devices 3 and 3 are provided in the drying chamber 1. When the mist is sprayed into the space 4 on the liquid surface of the pure water 40, the balance between the left and right mist spray states can be adjusted. As a result, the temperature of the mist is higher than the room temperature or the temperature of the wafer 2, preferably at least 5 ° C. or higher than the room temperature or the temperature of the wafer 2, and more preferably in the range of 5 ° C. to 60 ° C. Sprayed at high temperatures. When the nitrogen gas is supplied to each of the left and right mist spraying devices 3, 3, the nitrogen gas is supplied into the nitrogen gas passage 3 a in one direction from one end of each mist spraying device 3 toward the other end closing portion. It should be done. This has the advantage that the structure is simple. However, when pressure loss occurs in the nitrogen gas passage 3a and it is not possible to uniformly inject nitrogen gas from the injection holes 3e of all the nitrogen gas ejection passages 3b, one end of each mist spray device 3 is If nitrogen gas is supplied into the nitrogen gas passage 3a from both of the other ends simultaneously toward the middle between the two, pressure loss can be prevented in the nitrogen gas passage 3a, and nitrogen gas can be supplied. Injection can be made uniformly from the injection holes 3e.

In addition, the IPA sends nitrogen gas separately from the above into the IPA pumping tank 5 through the pressure reducing valve 10 and the second air operated valve 11, and the IPA in the IPA pumping tank 5 is pressurized by the pressure of the nitrogen gas. The liquid 6 is supplied to a third air operated valve 13, a flow meter 14, and manual valves 15 and 16.
Mist spray devices 3, 3 arranged on the left and right of FIG.
Respectively. Reference numeral 12 denotes a relief valve for the IPA pressure feeding tank. Third air operated valve 13
Preferably, the flow rate of the IPA liquid is automatically adjusted based on the flow rate of the IPA liquid detected by the flow meter 14. The manual valves 15 and 16 are disposed in the left and right mist spraying devices 3 and 3, respectively, and the opening and closing degrees of the manual valves 15 and 16 are adjusted to allow the left and right mist spraying devices 3 and 3 to operate in the drying chamber 1. When the mist is sprayed into the space 4 above the liquid surface of the pure water 40, the balance between the left and right mist spray states can be adjusted. When supplying the IPA liquid to each of the left and right mist spraying devices 3 and 3,
What is necessary is just to supply the IPA liquid into the IPA passage 3c in one direction from one end side of each mist spray device 3 to the other end closing portion. This has the advantage that the structure is simple. However, pressure loss occurs in the IPA passage 3c, and the injection holes 3 of all the IPA ejection passages 3d
If it is not possible to spray the IPA liquid uniformly from f and spray a uniform mist of IPA, the IPA liquid is simultaneously directed from both one end side and the other end side of each mist spraying device 3 toward the middle between the two. By supplying the IPA into the IPA passage 3c, pressure loss can be prevented in the IPA passage 3c, and the IPA liquid is uniformly ejected from the ejection holes 3f to spray a uniform IPA mist. Can be.

In order to prevent the pressure in the space 4 above the level of the pure water 40 in the drying chamber 1 from abnormally increasing, a discharge passage 44 is provided, and a manual operation for adjusting the discharge flow rate is performed. A valve 8 and a fourth air operated valve 9 for starting or stopping discharge are provided. It is also possible to arrange a pressure sensor in the space 4 and automatically open and close the fourth air operated valve 9 according to the pressure in the space 4 detected by the pressure sensor. Further, a discharge passage 45 for discharging the pure water 40 is provided at the bottom of the drying chamber 1, and a fifth air operated valve 7 is provided in the discharge passage 45 to adjust the discharge flow rate.

The first air operated valve 18, the second air operated valve 11, the third air operated valve 13, the fourth air operated valve 9, and the fifth air operated valve 7 are connected to a control device 41,
The drying room 1 is automatically set based on a predetermined program.
The flow rates of the nitrogen gas and the IPA liquid to be supplied into the chamber, the spray state of the IPA mist, the amount of exhaust from the space 4 in the drying chamber 1 and the amount of pure water 40 discharged can be controlled. ing.

According to the above configuration, the pure water 40 is supplied into the drying chamber 1 with the exhaust passage 44 closed, and when the wafer 2 is immersed in the supplied pure water 40, the mist sprayers 3, 3 At the same time, the IPA liquid is injected near the injection opening of the nitrogen gas to spray a mist of the IPA into the space 4 at, for example, about 2 cc / min. The direction in which the mist is sprayed is a slightly downward direction that is substantially directed toward the wafer 2 in the pure water 40 (specifically, a direction that is directed to a space between the adjacent wafers 2 and 2 and a position corresponding to the center of the wafer 2). It is preferable that the mist is uniformly held on the liquid surface of the pure water 40. At this time, when the pressure in the space 4 of the drying chamber 1 becomes abnormally high, it is preferable to open the discharge passage 44 to reduce the pressure.

In the state where the mist is continuously sprayed so that the liquid level of the pure water 40 in the space 4 is covered with the mist of the IPA, the fifth control is performed by the control device 41. The air operated valve 7 is opened, and the pure water 40 is gradually discharged from the drying chamber 1. As an example of the discharge speed, when the mist is sprayed at about 2 cc / min, for example, when the liquid level of the pure water 40 is 2
mm.

As a result, the upper portion of the wafer 2 is exposed from the pure water 40, but the surface of the wafer is not sprayed with oxygen and spontaneously oxidized, and is continuously sprayed uniformly on the liquid surface of the pure water 40. The mist of the IPA is immediately replaced with pure water adhering to the front and back surfaces of the wafer 2. Further, the temperature of the mist of the IPA is higher than the temperature of the wafer 2, that is, normal temperature (for example, higher than the temperature of the wafer 2, that is, higher than normal temperature up to 60 ° C.), preferably at least 5 ° C. or more, more preferably 5 ° C. If the temperature is raised in the range of from 60 ° C. to 60 ° C., it is dried quickly. Thereafter, the IPA spontaneously evaporates from the front and back surfaces of the wafer 2, thereby drying the front and back surfaces of the wafer 2. When the wafer 2 is at room temperature, the IPA or nitrogen gas or the IPA and nitrogen gas are set to a temperature higher than room temperature in the range of 5 ° C. to 60 ° C.
It is possible to dry more quickly if spraying is performed, for example, it is possible to dry less than 10 minutes for 50 wafers.

According to the first embodiment, the mist of IPA is always kept on the liquid surface of the pure water in which the wafer 2 is immersed, so that the upper part of the wafer 2 is exposed from the pure water 40. That is, the IPA mist uniformly supplied to the liquid surface of the pure water 40 immediately replaces the pure water adhering to the front and back surfaces of the wafer 2 without the wafer surface being exposed to oxygen and naturally oxidizing. Is done. If the temperature of the IPA is higher than the temperature of the wafer 2, that is, higher than room temperature, preferably at least 5 ° C. or higher, and more preferably in the range of 5 ° C. to 60 ° C., the IPA is condensed on both the front and back surfaces of the wafer 2. The wafer 2 is easily attached, is easily replaced by pure water adhering to the front and back surfaces of the wafer 2, and the front and back surfaces of the wafer 2 are quickly dried. Therefore, after replacing the pure water on the surface of the normal-temperature wafer with the normal-temperature IPA, the drying time is earlier than in the conventional case of drying the normal-temperature IPA, and the drying efficiency can be improved. In addition, pure water 40
Therefore, the consumption of IPA can be greatly reduced as compared with the conventional case where IPA is supplied by steam. When IPA is supplied by steam, it is necessary to cover the outside of the pipe with a heat insulating material in order to maintain the vapor state. However, in the first embodiment, for example, the IPA of the liquid phase at room temperature is simply Since it suffices to supply the mist to the mist spraying devices 3 and 3, it is not necessary to cover the pipe with a heat insulating material, and the device is simplified. In addition, although energy for heating is required when evaporating IPA, in the first embodiment, it is sufficient if there is energy enough to inject nitrogen gas and IPA from the mist spraying device 3 and it is inexpensive. The mist of IPA can be formed with a simple and simple device configuration. In this way, it is possible to inject the liquid phase IPA at the same time as injecting the nitrogen gas from the side opposite to each other, and to fill the IPA mist into the space of the drying chamber, and apply the IPA mist to both the front and back surfaces of the wafer. I
The PA mist can be sprayed, and the IPA mist can be supplied to the entire front and back surfaces of the wafer.
In addition, the liquid phase I
Rather than using PA as a mist, without using electrical energy, by injecting IPA from the IPA injection nozzle near the nitrogen gas injection hole, it is possible to mist the liquid phase IPA, The spraying operation of the IPA mist can be performed more safely and more stably with respect to the highly flammable IPA.

The present invention is not limited to the first embodiment, but can be implemented in various other modes. For example, the mist spray device 3 is not limited to the one shown in FIG. 2, but may be a mist spray device 23 as shown in FIG. FIG. 3 shows a rectangular parallelepiped main body 2 made of porous fluororesin.
4, one nitrogen gas passage 23a and two IPA passages 23c, 23c are respectively formed, and the surface of the rectangular parallelepiped main body 24 excluding the surface facing the wafer 2 is made of porous material. No ordinary fluororesin coating 2
The coating with 5 prevents nitrogen gas and IPA from being emitted from the surface coated with the coating 25. Since the rectangular parallelepiped main body 24 is porous, the nitrogen gas is passed through the nitrogen gas passage 23a disposed at a position close to the surface opposite to the surface 23e on the ejection surface 23e not covered with the covering member 25. When is ejected from the ejection surface 23e, the IPA liquid is ejected from the ejection surface 23e also from the IPA passages 23c and 23c disposed closer to the ejection surface 23e than the nitrogen gas passage 23a, as shown in FIG. Mist can be sprayed in almost the same way. In this example, instead of spraying the mist at predetermined intervals, the mist can be sprayed from substantially the entire ejection surface 23 e facing the wafer 2. When supplying the nitrogen gas and the IPA liquid to each of the left and right mist spraying devices 3 and 3, respectively, from one end of each mist spraying device 3 toward the other end closing portion and from the other end toward the one end closing portion. The nitrogen gas and the IPA liquid may be supplied in one direction into the nitrogen gas passage 23a and the IPA passage 23c. This has the advantage that the structure is simple. However, pressure loss occurs in the nitrogen gas passage 23a and the IPA passage 23c, and all the nitrogen gas ejection passages 23a and the IPA
When the nitrogen gas and the IPA liquid cannot be sprayed uniformly from the passage 23c, the nitrogen gas passage 23a and the IPA passage 23c are formed so as to penetrate along the longitudinal direction of the rectangular parallelepiped main body 24, respectively. Nitrogen gas and IPA liquid are simultaneously supplied from both one end side and the other end side of the mist spraying device 3 toward the middle between the two sides, and the nitrogen gas passage 23a.
And the IPA passage 23c, pressure loss can be prevented in the nitrogen gas passage 3a and the IPA passage 23c.
The liquid can be sprayed uniformly.

According to the above embodiment, in addition to the functions and effects of the above embodiment, since the rectangular parallelepiped main body 24 is made of porous fluororesin, the rectangular parallelepiped main body 24 has strong water repellency. Even when immersed in pure water, the pure water does not penetrate into the inside, and the IPA of the liquid phase before the mist state is formed.
Does not mix with the pure water in the drying chamber 1 which is the washing water. Further, since the entire surface is porous, the mist can be sprayed from substantially the entire surface of the ejection surface 23 e facing the wafer 2, and the mist can be more uniformly sprayed on the wafer 2. In addition, as in the first embodiment, the mist spraying device 3 is not limited to the device in which the mist spraying device 3 is jetted from the side as shown in FIG. As a second embodiment of the present invention, as shown in FIG. The other configuration is the same as that of the first embodiment, and the description is omitted.
With such a configuration, simultaneously with injecting nitrogen gas downward, liquid-phase IPA can be ejected, and the IPA mist can be sprayed from the top to the bottom on both front and back surfaces of the wafer. IPA mist can be supplied to the whole of the front and back surfaces.

Instead of discharging the pure water 40 from the drying chamber 1, the wafer 2 is raised in the drying chamber 1 and the wafer 2 is separated from the pure water 40 in the drying chamber 1. You may make it expose above a surface.

[0030]

According to the present invention, the mist of IPA, that is, nitrogen is not used as a carrier, but the IPA itself floats alone in the nitrogen gas on the liquid surface of the pure water in which the wafer is immersed. Is maintained at all times, so that the top of the wafer is exposed from pure water.However, the surface of the wafer is uniformly supplied to the liquid surface of the pure water without being exposed to oxygen and naturally oxidized. The mist of the IPA is immediately replaced with pure water adhering to the front and back surfaces of the wafer. Further, if the temperature of the mist of IPA is higher than the temperature of the wafer, that is, normal temperature, preferably higher by at least 5 ° C., and more preferably in the range of 5 ° C. to 60 ° C.,
IPA easily adheres to the front and back surfaces of the wafer, and is easily replaced with pure water attached to the front and back surfaces of the wafer, and the front and back surfaces of the wafer dry quickly.

Therefore, after replacing the pure water on the surface of the wafer at room temperature with the IPA at room temperature, the drying time is earlier than in the conventional case of drying the IPA at room temperature, and the drying efficiency can be improved. Further, since the pure water is sprayed on the liquid surface in a mist state, the consumption of IPA can be significantly reduced as compared with the conventional case where IPA is supplied by steam. Further, when IPA is supplied by steam, it is necessary to cover the outside of the pipe with a heat insulating material or the like in order to maintain the vapor state. Since it is only necessary to supply IPA to each of the mist spraying devices, there is no need to cover the piping with a heat insulating material.
The device becomes simple. Further, when IPA is vaporized, energy for heating is required. However, in the present invention, it is sufficient if there is energy enough to inject nitrogen gas and IPA, and the apparatus is inexpensive and has a simple device configuration. A mist of IPA can be formed.

If the rectangular parallelepiped main body of the mist spraying device is made of a porous fluororesin, the rectangular parallelepiped main body has high water repellency, and even when immersed in pure water, pure water enters into the inside. Therefore, the IPA in the liquid phase before the mist state is not mixed with the pure water in the drying chamber, which is the washing water. Further, since the entire surface is porous, the mist can be sprayed from substantially the entire ejection surface facing the wafer, and the mist can be more uniformly sprayed on the wafer. Also, instead of using liquid energy IPA as mist by electric energy such as ultrasonic waves, the IPA is injected from the IPA injection nozzle near the nitrogen gas injection hole without using electric energy. , Liquid phase I
Since PA can be converted to mist, I
The PA can perform the spraying operation of the IPA mist more safely and more stably.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a wafer drying apparatus according to a first embodiment of the present invention.

FIGS. 2A and 2B are a plan view and a cross-sectional view, respectively, of a mist spraying device of the wafer drying device of FIG. 1;

FIGS. 3A and 3B are a plan view and a cross-sectional view, respectively, of a mist spraying device of the wafer drying device according to a modification of the embodiment.

FIG. 4 is a schematic configuration diagram of a wafer drying apparatus according to a second embodiment of the present invention.

[Explanation of symbols]

1. Drying chamber, 2. Wafer, 3. Mist sprayer, 3a ...
Nitrogen gas passage, 3b ... Nitrogen gas ejection passage, 3c ... I
PA passage, 3d IPA ejection passage, 3e, 3f injection hole, 4 space, 5 IPA pumping tank, 6 liquid, 7
... Fifth air operated valve, 8 ... Manual valve, 9 ... Fourth
Air operated valve, 10: pressure reducing valve, 11: second air operated valve, 12: relief valve for IPA pressure feeding tank, 13: third air operated valve, 14: flow meter, 15, 16: manual valve, 17: pressure reducing valve , 18 ... 1st
Air operated valve, 19 ... flow meter, 20, 21 ...
Manual valve, 23: Mist spraying device, 23a: Nitrogen gas passage, 23c: IPA passage, 23e: Spout surface, 24: Porous fluororesin rectangular parallelepiped body, 40: Pure water, 4
1. Control device, 44 discharge passage, 45 discharge passage.

Claims (16)

[Claims] A nitrogen gas is injected into a drying chamber (1) in which a wafer (2) can be immersed in pure water (40), and a space (4) in the drying chamber above the level of the pure water. At the same time, a mist spraying device (3, 23) for injecting isopropyl alcohol in a liquid phase at a temperature higher than the temperature of the wafer and near the injection opening of the nitrogen gas to spray mist-like isopropyl alcohol into the space. Either by discharging the pure water in the drying chamber or by raising the wafer in the drying chamber, when the wafer is exposed above the liquid level from the pure water in the drying chamber,
Pure water adhering to the front and back surfaces of the wafer is replaced by the mist-like isopropyl alcohol, and thereafter,
A wafer drying apparatus wherein the isopropyl alcohol is dried by evaporation from both the front and back surfaces of the wafer. 2. The mist-like isopropyl alcohol is sprayed into the space by injecting the isopropyl alcohol in the liquid phase at a temperature higher than the temperature of the wafer by at least 5 ° C. and in the vicinity of an injection opening of the nitrogen gas. 2. The wafer drying apparatus according to 1. 3. The wafer drying apparatus according to claim 1, wherein the wafer is at room temperature, and the mist is approximately 30 ° C. or higher. 4. The wafer drying apparatus according to claim 1, wherein the mist-like isopropyl alcohol is a state in which the isopropyl alcohol itself is floating alone in the nitrogen gas. 5. The wafer drying apparatus according to claim 1, wherein the isopropyl alcohol is sprayed in a mist at a temperature higher by 5 ° C. to 60 ° C. than the temperature of the wafer. 6. A wafer (2) is immersed in pure water (40) in a drying chamber (1), and nitrogen gas is injected into a space (4) above the pure water level in the drying chamber. At the same time, isopropyl alcohol in the liquid phase is sprayed at a temperature higher than the temperature of the wafer and near the spray opening of the nitrogen gas to spray mist-like isopropyl alcohol into the space. By discharging the water or raising the wafer in the drying chamber, when the wafer is exposed above the liquid level from the pure water in the drying chamber, the pure water attached to the front and back surfaces of the wafer is Replaced by the mist-like isopropyl alcohol,
Thereafter, the wafer is dried by evaporation of the isopropyl alcohol from both front and back surfaces of the wafer. 7. The mist of isopropyl alcohol is sprayed into the space by injecting the isopropyl alcohol in the liquid phase at a temperature at least 5 ° C. higher than the temperature of the wafer and near the injection opening of the nitrogen gas. 7. The wafer drying method according to 6. 8. The wafer drying method according to claim 6, wherein the wafer is at room temperature, and the mist is approximately 30 ° C. or higher. 9. The wafer drying method according to claim 6, wherein the mist-like isopropyl alcohol is a state in which the isopropyl alcohol itself is floating alone in the nitrogen gas. 10. The temperature of the wafer is 5 ° C. to 60 ° C.
10. The wafer drying method according to claim 6, wherein the isopropyl alcohol is sprayed in a mist at a high temperature. 11. The mist spraying device (23) includes a first injection hole (3e) for injecting the nitrogen gas, and a second injection arranged near the injection hole and for injecting the liquid isopropyl alcohol. A hole (3f);
Inject the nitrogen gas from the injection hole and simultaneously
The wafer drying apparatus according to any one of claims 1 to 5, wherein the mist-like isopropyl alcohol is sprayed into the space by spraying the liquid-phase isopropyl alcohol from a spray hole. 12. The mist spraying device (23) has a rectangular parallelepiped main body (2) made of porous fluororesin having high water repellency.
4) a first passage (23a) for supplying the nitrogen gas;
And a second passage (23c) that is disposed closer to the wafer-facing surface of the main body than the first passage and supplies the liquid isopropyl alcohol, and supplies the nitrogen gas to the first passage. At the same time, the liquid-phase isopropyl alcohol is supplied to the second passage, and the liquid-phase isopropyl alcohol is injected together with the nitrogen gas from the wafer-facing surface of the porous rectangular parallelepiped main body to form the mist-like isopropyl alcohol. The wafer drying apparatus according to any one of claims 1 to 5, wherein the apparatus is a device that sprays alcohol into the space. 13. The method according to claim 1, wherein the nitrogen gas is injected at a high temperature equal to or higher than the temperature of the wafer or up to 60 ° C. over the temperature of the wafer.
13. The wafer drying device according to any one of 11 and 12. 14. The temperature of the wafer is 5 ° C. to 60 ° C.
The wafer drying apparatus according to any one of claims 1 to 5, wherein the nitrogen gas is injected at a high temperature in a range up to. 15. The method according to claim 6, wherein the nitrogen gas is injected at a high temperature equal to or higher than the temperature of the wafer or up to 60 ° C. over the temperature of the wafer.
The method for drying a wafer according to any one of the above. 16. The temperature of the wafer is 5 ° C. to 60 ° C.
The wafer drying method according to any one of claims 6 to 10, wherein the nitrogen gas is jetted at a high temperature in a range up to.