Drying and gas or vapor contact with solids – Process – With nondrying treating of material
Reexamination Certificate
1999-11-23
2001-04-24
Gravini, Stephen (Department: 3749)
Drying and gas or vapor contact with solids
Process
With nondrying treating of material
C034S404000, C034S405000, C034S076000, C034S079000, C034S202000, C034S221000
Reexamination Certificate
active
06219936
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a wafer drying apparatus and method for drying the surface of the wafer immersed in pure water without causing the wafer to contact oxygen when the wafer is taken out from the pure water.
Conventionally, as in a drying apparatus disclosed in Japanese Patent Publication No. 6-103686, with nitrogen gas used as a carrier, IPA (isopropyl alcohol) is supplied in the form of vapor into an upper space in a wafer treating bath which contains a wafer treated with an etching liquid and cleaned with pure water. Then, the pure water in the treating bath is drained so that the wafer is exposed in the treating bath, whereby the IPA vapor supplied to the upper space of the treating bath is replaced with water drops held to the surface of the wafer, and so that the surface of the wafer is enabled to dry without naturally oxidizing due to contact with oxygen.
With an apparatus of the above mentioned construction, however, usually an IPA vapor of an ordinary temperature, equal to the wafer temperature that is an ordinary temperature, is supplied into the treating bath for replacement, and this involves long drying time from the evaporation of the IPA of the ordinary temperature to the drying of the wafer surface, which poses an issue of poor drying efficiency.
SUMMARY OF THE INVENTION
Therefore, the present invention is intended to solve the above mentioned issue. To this end the object of the present invention is to provide a wafer drying apparatus and method which enable fast drying of mist-form IPA from the surface of a wafer at a higher temperature than the temperature of the wafer, thereby to reduce the amount of time required for drying by replacing water drops held to the surface of the wafer by the mist-form IPA, thus enhancing drying efficiency.
In order to accomplish the above mentioned object, the present invention has the following constructions.
According to a first aspect of the present invention, there is provided a wafer drying apparatus comprising: a drying chamber capable of immersing a wafer in pure water; and a mist spraying device for jetting nitrogen gas into a space on a liquid level of the pure water in the drying chamber and, simultaneously therewith, injecting isopropyl alcohol of liquid-phase into the space at a temperature higher than a temperature of the wafer and in the vicinity of an opening for jetting the nitrogen gas, thus spraying isopropyl alcohol of mist-form in the space. When the wafer is exposed above from the liquid level of the pure water in the drying chamber by discharging the pure water in the drying chamber from the drying chamber or elevating the wafer in the drying chamber, the pure water held on the front and rear surfaces of the wafer is replaced by the isopropyl alcohol of mist-form. Then the isopropyl alcohol is evaporated from the front and rear surfaces of the wafer whereby the wafer is dried.
According to a second aspect of the present invention, there is provided a wafer drying apparatus as defined in the first aspect, wherein the isopropyl alcohol of the liquid phase is injected at a temperature higher by at least 5° C. or more than the temperature of the wafer in the vicinity of the nitrogen gas injection opening so that the isopropyl alcohol of mist-form is sprayed into the space.
According to a third aspect of the present invention, there is provided a wafer drying apparatus as defined in the first or second a spect, wherein the wafer is of an ordinary temperature and the temperature of the mist is of generally not less than 30° C.
According to a fourth aspect of the present invention, there is provided a wafer drying apparatus as defined in any one of the first through third aspects, wherein the isopropyl alcohol of mist-form is of such a state that the isopropyl alcohol per se is suspended alone in the nitrogen gas.
According to a fifth aspect of the present invention, there is provided a wafer drying apparatus as defined in any one of the first through fourth aspects, wherein the isopropyl alcohol is sprayed in mist-form at a temperature 5° to 60° C. higher than the temperature of the wafer.
According to a sixth aspect of the present invention, there is provided a wafer drying method comprising: immersing a wafer in pure water in a drying chamber; jetting nitrogen gas into a space at a liquid level of the pure water in the drying chamber, and simultaneously thereupon spraying isopropyl alcohol of liquid phase at a temperature higher than a temperature of the wafer and in the vicinity of an opening for jetting the nitrogen gas, thus spraying isopropyl alcohol of mist-form in the space. When the wafer is exposed above from the liquid level of the pure water in the drying chamber by discharging the pure water in the drying chamber from the drying chamber or elevating the wafer in the drying chamber, the pure water held on front and rear surfaces of the wafer is replaced by the isopropyl alcohol of mist-form. Then the isopropyl alcohol is evaporated from the front and rear surfaces of the wafer whereby drying the wafer.
According to a seventh aspect of the present invention, there is provided a wafer drying method as defined in the sixth aspect, wherein the isopropyl alcohol of liquid phase is jetted at a temperature at least 5° C. higher than the temperature of the wafer in the vicinity of the jetting opening of the nitrogen gas to spray the isopropyl alcohol of mist-form into the space.
According to an eighth aspect of the present invention, there is provided a wafer drying method as defined in the sixth or seventh aspect, wherein the wafer is of an ordinary temperature and the temperature of the mist is generally not less than 30° C.
According to a ninth aspect of the present invention, there is provided a wafer drying method as defined in any one of the sixth through eighth aspects, wherein the isopropyl alcohol of mist-form is of such a state that the isopropyl alcohol per se is suspended alone in the nitrogen gas.
According to a tenth aspect of the present invention, there is provided a wafer drying method as defined in any one of the sixth through ninth aspects, wherein the isopropyl alcohol is sprayed in mist-form at a temperature 5° C. to 60° C. higher than the temperature of the wafer.
According to an eleventh aspect of the present invention, there is provided a wafer drying apparatus as defined in any one of the first through fifth aspects, wherein the mist spraying device includes a first jetting hole for jetting the nitrogen gas, and a second jetting hole disposed adjacent to the first jetting hole, for jetting the isopropyl alcohol of liquid-phase, whereby simultaneously with nitrogen gas jetting from the first jetting hole, the isopropyl alcohol of liquid-phase is jetted from the second jetting hole, thereby spraying the isopropyl alcohol of mist-form in the space.
According to a twelfth aspect of the present invention, there is provided a wafer drying apparatus as defined in any one of the first through fifth aspects, wherein the mist spraying device includes: a first passage for supplying the nitrogen gas to a rectangular parallelopiped porous fluoroplastic body having high water repellency; and a second passage provided nearer to a wafer-facing side of the body than the first passage, for supplying the isopropyl alcohol of liquid-phase. In the mist spraying device, simultaneously with the nitrogen gas being supplied to the first passage, the isopropyl alcohol of liquid phase is supplied to the second passage, whereby the nitrogen gas and the isopropyl alcohol of liquid phase are jetted together from wafer-facing surfaces of the rectangular parallelopiped porous body, thereby spraying the mist-form isopropyl alcohol into the space.
According to a thirteenth aspect of the present invention, there is provided a wafer drying apparatus as defined in any one of the first through fifth, eleventh, and twelfth aspects, wherein the nitrogen gas is jetted at a temperature equal to the temperature of the wafer or a temperature higher than the temperature of the wafer wi
Kedo Yutaka
Matsuda Susumu
Takemura Yoshio
Gravini Stephen
Toho Kasei Co., Ltd.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Wafer drying device and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Wafer drying device and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wafer drying device and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2522752