KR20050006717A - Method and apparatus for wafer drying - Google Patents

Abstract

PURPOSE: An apparatus for drying a wafer is provided to minimize wafer contamination caused by remnants and maximize a water particle eliminating effect on the surface of a wafer by rapidly exhausting N2 gas and the remnants during a dry process. CONSTITUTION: A wafer guide(120) is placed in a process bath(111). Injection holes for injecting dry gas to the process bath are provided to eliminate the water remaining on a wafer. An exhaust part exhausts the remnants including the dry gas injected to the inside of the process bath and the vapor evaporated by the dry gas. The exhaust position of the remnants is not varied in the exhaust part during a process.

Description

Wafer Drying Apparatus and Method {METHOD AND APPARATUS FOR WAFER DRYING}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing apparatus used in a wafer cleaning process, and more particularly, to a wafer drying apparatus and method for drying a wafer after cleaning the wafer.

Background Art With the high integration of semiconductor devices, the technology for cleaning wafers in semiconductor manufacturing processes is becoming more diversified, and their importance is increasing. Particularly in the manufacturing process of semiconductor devices having a microstructure, static electricity, watermarks, line particles, etc., as well as particles adhered to the wafer after the wafer cleaning process have a great influence on subsequent processes. Therefore, the necessity of the drying process of a wafer further increases.

The wafer drying apparatus used for the manufacture of semiconductor devices has developed in various directions. They are as follows. One is a spin dryer for drying the wafer using centrifugal force, and the other is a drying device for drying the wafer using a low vapor pressure of isopropyl alcohol (IPA) (hereinafter referred to as IPA drying device). to be. However, the spin dryer and the IPA vapor dryer cannot completely remove the water mark between the wafer surface and the pattern. Therefore, recently, a Marangoni type drying apparatus using the difference between the surface tension and the vapor pressure of IPA and water is mainly used. This marangoni-type drying apparatus is a method in which the surface tension of water, the density of IPA, and the surface tension are different, and a wafer is dried by floating an IPA layer having a drying effect on the water.

Briefly looking at the drying process using this marangoni principle, the wafer is first cleaned with deionized water. When cleaning of the wafer is completed, dry gas (IPA, nitrogen gas) is injected into the treatment tank while draining deionized water to remove moisture from the surface of the wafer. When the deionized water in the treatment tank is completely drained, hot nitrogen gas is injected to evaporate the deionized water remaining in the form of fine particles on the wafer surface with water vapor.

However, the drying apparatus using this marangoni principle has the following problems.

Conventionally, since the exhaust port is located in the upper part of the treatment tank, when the water level of the treatment tank is lowered, structural problems in which residues (including evaporated water vapor and particles) generated during the drying process cannot escape quickly (smoothly) to the outside Have As a result, these residues, together with the dry gas injected from the top of the treatment tank, form an irregular flow (turbulence) inside the treatment tank. Therefore, the surface drying of the wafer is not uniform, and in particular, drying defects such as more water remain at the lower end than the upper end of the wafer occur.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a wafer drying apparatus and method capable of quickly evacuating residues remaining on the water surface during a drying process. Another object of the present invention is to provide a drying apparatus that can increase the drying efficiency. Another technical problem to be achieved by the present invention is to provide a drying apparatus and method capable of preventing turbulent flow in the treatment tank.

1 is a view for explaining a wafer drying apparatus according to a preferred embodiment of the present invention;

2 to 3 show that the position where the residues are exhausted is changed according to the change in the water level of the treatment tank in FIG. 1;

4 illustrates a modified example of the variable exhaust unit illustrated in FIG. 1.

5 and 6 are views for explaining a modified wafer drying apparatus according to a preferred embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

111: treatment tank 112: inner tank

114: the outer tank 116: cover

120: wafer guide 130: gas distributor

142: distribution pipe 152a: first drain pipe

154: control valve 180,200: variable exhaust

182: exhaust port 184: door

186 control unit 188 detection sensor

In order to achieve the above technical problem, the present invention and the processing tank is placed; Injection holes for injecting dry gas into the processing tank to remove water remaining on the wafer; Provided is a drying apparatus having a drying gas injected into the treatment tank and a variable exhaust portion whose exhaust position of the residues is changed during the process.

In the present invention, the exhaust portion is gradually or stepwise changed in accordance with the change of the level of the cleaning liquid so that the residues are exhausted near the surface of the cleaning liquid of the treatment tank.

In the present invention, the exhaust portion and the exhaust port is provided at a predetermined height in the treatment tank; A door installed at the exhaust port and for opening and closing the exhaust port; It includes a control unit for operating the door for opening and closing at least one exhaust port in accordance with the level of the cleaning liquid.

In the present invention, the exhaust ports are provided on at least one side of the treatment tank.

At least one moving tube having an exhaust port and installed in the treatment tank in the present invention; And a moving member for elevating the moving tube according to the level of the cleaning liquid. The exhaust part further includes a sensor for checking the level of the cleaning liquid. The exhaust port is a wafer drying apparatus, characterized in that the slot form.

Another aspect of the present invention is to supply a cleaning liquid into the treatment tank to clean the substrate; Spraying a dry gas while discharging the liquid in the treatment tank so that the substrate is gradually exposed on the surface of the cleaning liquid; And exhausting the drying gas and residues including water vapor at a height corresponding to the change in the level of the cleaning liquid.

In the present invention, the step of evacuating the residues comprises: checking the level of the cleaning liquid; Changing the positions of the exhaust ports through which residues are exhausted according to the change in the level of the cleaning liquid.

In the present invention, the step of evacuating the residues comprises: checking the level of the cleaning liquid; Selectively opening at least one exhaust port closest to the surface of the cleaning liquid according to a change in the level of the cleaning liquid.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed subject matter is thorough and complete, and that the spirit of the present invention to those skilled in the art will fully convey. Portions denoted by like reference numerals denote like elements throughout the specification.

1 is a view showing a wafer drying apparatus according to a preferred embodiment of the present invention.

Referring to FIG. 1, the wafer drying apparatus 100 according to the present invention includes a chamber 110, a gas distributor 130, a liquid flow system, and a variable exhaust unit 180.

The chamber 110 has a treatment tank 111 and a cover 116. The treatment tank 111 is composed of an inner tank 112 for immersing and cleaning the substrate W and an outer tank 114 surrounding the inner tank. The inner tank 112 of the treatment tank 111 has a bottom 112a and sidewalls 112b and provides a space surrounded by them. The treatment tank 111 has an exhaust port 113 extending from the bottom of the inner tank. The treatment tank 111 has an open shape toward the upper portion, the opening of the treatment tank 111 is opened and closed by the cover 116. An o-ring for sealing is installed at the contact portion of the cover 116 and the treatment tank 111.

The wafers w in the processing tank 111 are supported by the wafer guide 120. The wafer guide 120 may be composed of at least three bars 122a and 122b disposed in parallel with a direction crossing the wafers w. For example, the wafer guide 120 is composed of one center bar 122a and two side bars 122b positioned at both sides of the center bar 122a. The wafer guide 120 may be connected to a lift (not shown) that raises or lowers the wafers W. FIG.

The gas distributor 130 is installed in the cover 116. The gas distributor 130 includes a plurality of nozzles. The gas distributor 130 uniformly supplies IPA and inert gas such as nitrogen gas at room temperature or heated to the inside of the treatment tank 111 from the upper portion of the treatment tank 111.

The liquid flow system has means for continuously supplying liquid into the treatment tank 111 and means for continuously discharging the liquid from the treatment tank 111. These means control the level and discharge of the liquid in the treatment tank 111. The supply means has a distribution pipe 142 which is installed in the longitudinal direction of the wafer guide 120 and formed with a plurality of injection holes 144 under the processing tank 111. The distribution pipe 142 receives liquid from an external liquid supply source through a liquid supply pipe.

The discharge means includes first and second drain pipes 152a and 152b connected to the discharge port 113 of the treatment tank 111, and on / off valves 154a and second drain pipes installed in the first drain pipe. It includes an open and close adjustable flow valve 154b. For example, the second drain pipe 152b includes a device (flow control valve) or a metering pump for draining at a desired speed (1-2 mm / s). Control of the liquid level in the treatment tank 111 is achieved by adjustment of the valve 154b.

Here, the liquid is used to carry out the washing process. The cleaning process corresponds to a process of cleaning the wafers w or a process of rinsing the wafers w. Therefore, when the cleaning process corresponds to the cleaning process, the liquid may be a chemical solution suitable for removing contaminants such as particles or natural oxide film remaining on the wafers w. In addition, when the cleaning process corresponds to the rinse process, it may be deionized water suitable for removing the chemical solution remaining on the wafers (w).

The wafer drying apparatus has a variable exhaust unit 180 through which residues including dry gases IPA and N2 injected into the processing tank and water vapor evaporated by the dry gases are exhausted.

In the variable exhaust unit 180, the exhaust positions of the residues vary according to the level of the cleaning liquid. The variable exhaust unit 180 has a structural feature in which the exhaust position of the residues is changed according to a change in the level of the cleaning liquid so that the residues can be exhausted near the surface of the cleaning liquid of the treatment tank 111.

Referring to FIG. 1, the variable exhaust unit 180 has four exhaust ports 182 formed on both sides of the inner tank 112, and the exhaust holes 182 are spaced at a side of the inner tank 112. Is formed with. Each exhaust port 182 is provided with a door 184, the opening and closing of the door 184 is controlled by the control unit 186. The variable exhaust unit 180 has sensors 188 for detecting the level of the inner tank 112, and the controller 186 receives a detection signal from the detection sensors 188. The control unit 186 operates the door 184 to open at least one exhaust port 182 according to the level of the cleaning liquid. For example, it is preferable to open the exhaust port closest to the surface of the cleaning liquid.

As shown in Figs. 2 and 3, the wafer drying apparatus 100 is one in which residues can be exhausted quickly and reliably through the exhaust port 182 closest to the surface of the cleaning liquid (exhaust flow of residues). With arrows).

FIG. 4 is a diagram for describing a modification of the variable exhaust unit illustrated in FIG. 1.

The wafer drying apparatus 100a shown in FIG. 4 has the same configuration as the apparatus shown in FIG. However, without installing a door in the exhaust port 202 of the variable exhaust unit 200, an exhaust line 204 is connected to each of the exhaust ports 202, and the exhaust line 204 uses a shutoff valve 206. It has a structural feature to open and close. Reference numeral 208 denotes a water level sensor, and reference numeral 210 denotes a control unit.

Next, a drying method in the wafer drying apparatus shown in FIG. 1 will be described.

First, the wafers w are loaded into the processing tank 111. Deionized water is supplied into the treatment tank 111 through the distribution pipe 142. The deionized water is continuously supplied and discharged through the supply means and the discharge means to rinse the wafers w. After rinsing the wafers w, while supplying IPA and nitrogen gas to the upper portion of the deionized water in the treatment tank 111, the deionized water in the treatment tank 111 is gradually passed through the second drain pipe 152b. Discharge it. Accordingly, a drying process of removing deionized water remaining on the surfaces of the wafers w is performed.

Meanwhile, the variable exhaust unit 180 opens and closes the exhaust ports 182 according to the change in the water level in the treatment tank, and opens the exhaust port 182 adjacent to the water surface, thereby allowing the gas (N2, IPA) and fume used to dry the wafer. Residues, including fumes, are quickly exhausted through the vents 182. As such, the residues are rapidly exhausted through the exhaust pipes 182 closest to the water surface of the treatment tank 111, thereby preventing the occurrence of turbulence in the treatment tank 111. That is, the gas flow inside the treatment tank 111 may be maintained to be stable during the drying process. If an unstable air flow phenomenon such as vortex occurs inside the treatment tank during the drying process, it is difficult to obtain a water particle drying effect on the wafer surface by hot N 2 gas injection. Therefore, it is very important for the drying process to maintain the gas flow in the treatment tank 111 to be stabilized and quickly evacuated during the drying process. As a result, during the drying process, the N2 gas and the residues are quickly exhausted through the first exhaust pipe 172, and new N2 gas is provided to the wafer surface, thereby reducing wafer contamination by the residues. Minimize and maximize the effect of removing water particles on the wafer surface.

When the deionized water discharge in the treatment tank 111 is completed, the final wafer drying process is performed in the following process. This final wafer drying process removes deionized water remaining in the form of fine particles on the wafer surface using heated nitrogen gas.

5 and 6 show a wafer drying apparatus according to a modified embodiment.

The wafer drying apparatus 100 ′ shown in FIGS. 5 and 6 has a chamber 110, a gas distributor 130, a liquid flow system, and the like having the same configuration and function as the wafer drying apparatus shown in FIG. 1, Description of these has been described in detail above, so it will be omitted in this modification. However, in the present embodiment, it has a structural feature having a variable exhaust unit 190 which is elevated according to the level of the cleaning liquid.

As shown in FIGS. 5 and 6, the variable exhaust unit 190 has a moving tube 192 having one exhaust port 193. The moving tube 192 is installed on both sides of the treatment tank 111 to correspond to each other, the moving tube 192 is moved by the moving member 194 in accordance with the change in the level of the cleaning liquid. The moving member includes a wire 195 connected to the moving tube, a reel 196 on which the wire is wound, and a motor 197 for rotating the reel. The variable exhaust unit 190 may have a guide rail 198 for guiding the lifting and lowering of the moving tube 192 on the inner surface of the treatment tank. For example, the residues are introduced into the moving tube 192 through the exhaust port 193 and are exhausted through the exhaust line 199 connected to the moving tube 192. Reference numeral 194 denotes a water level sensor, and 191 denotes a control unit for controlling the motor. In some cases, the reel and the motor may be installed outside the treatment tank.

Another example of the moving member 194 may be a cylinder device using hydraulic pressure or a moving device using a motor and a gear.

In the above, the configuration and operation of the wafer drying apparatus according to the present invention have been shown in accordance with the above description and drawings, but this is merely described by way of example, and various changes and modifications can be made without departing from the technical spirit of the present invention. Of course.

As described above, according to the present invention, during the drying process, the N 2 gas and the residues are rapidly exhausted, thereby minimizing wafer contamination by the residues and maximizing the water particle removal effect on the wafer surface. .

Claims (10)

In the wafer drying apparatus: A processing tank in which the wafer guide is placed; Injection holes for injecting dry gas into the processing tank to remove water remaining on the wafer; And an exhaust portion through which residues including dry gas injected into the treatment tank and water vapor evaporated by the dry gas are exhausted; And wherein the exhaust portion is changed in the exhaust position of the residues during the process. The method of claim 1, The exhaust part And the exhaust position is gradually changed in accordance with the change in the level of the cleaning liquid so that the residues are exhausted near the surface of the cleaning liquid of the processing tank. The method of claim 2, The exhaust part Exhaust vents provided at predetermined heights in the treatment tank; A door installed at the exhaust port and for opening and closing the exhaust port; Wafer drying apparatus comprising a control unit for operating the door for opening and closing at least one exhaust port in accordance with the level of the cleaning liquid. The method of claim 3, wherein The exhaust port is a wafer drying apparatus, characterized in that installed on at least one side of the processing tank. The method of claim 2, The exhaust part At least one moving tube having an exhaust port and installed in the treatment tank; And a movable member for elevating the movable tube in accordance with the level of the cleaning liquid. The method of claim 2, The exhaust part Wafer drying apparatus further comprises a sensor for checking the level of the cleaning liquid. The method according to claim 3 or 5, The exhaust port is a wafer drying apparatus, characterized in that the slot form. In a method of drying a semiconductor substrate: Supplying a cleaning liquid into the treatment tank to clean the substrate; Spraying a dry gas while discharging the liquid in the treatment tank so that the substrate is gradually exposed on the surface of the cleaning liquid; And And drying the drying gas and the residues including water vapor at a height corresponding to a change in the level of the cleaning liquid. The method of claim 8, The evacuation of the residues Checking the level of the cleaning liquid; And changing the positions of the exhaust ports through which residues are exhausted according to the change in the level of the cleaning liquid. The method of claim 8, The evacuation of the residues Checking the level of the cleaning liquid; Selectively opening at least one exhaust port closest to the surface of the cleaning liquid according to a change in the level of the cleaning liquid.