KR100841995B1 - Apparatus and method for single wafer cleaning - Google Patents

Abstract

A single-type wafer cleaning apparatus and a method are provided to prevent re-absorption of pollution particles by performing a cleaning process in a sealed space under ozone atmosphere. A body(10) consists of dome-shaped upper and lower half-bodies, and a wafer mounting unit(60) is installed in the body to mount and rotate the wafer in the body. An ozone gas line(21) supplies an ozone gas in the body, and a nitrogen/inert gas line(40) supplies a nitrogen gas and an inert gas in the body. Plural gas spraying nozzles(20) are provided on upper and lower round surfaces of the body, and are selectively supplied with the ozone gas, the nitrogen gas and the inert gas. A cleaning solution spraying nozzle(50) sprays a cleaning solution onto the surface of the wafer, and a vacuum pump(70) drains the gas from the body. The body has an outer body(11) and an inner body(12), in which a gas layer(13) is formed between the outer body and the inner body.

Description

Single wafer cleaning apparatus and cleaning method {Apparatus and method for single wafer cleaning}

1 is a schematic cross-sectional view of a single wafer cleaning apparatus according to the present invention.

FIG. 2 is a schematic cross-sectional view of the upper cleaning liquid jet nozzle of the single wafer cleaning apparatus of FIG. 1 spaced apart from the outer circumference of the wafer. FIG.

3 is a flowchart of a single wafer cleaning method according to the present invention.

* Description of symbols on the main parts of the drawings *

10: main body 51: upper cleaning liquid jet nozzle

11: Outer Body Part 52: Lower Cleaning Liquid Injection Nozzle

12: internal main body 60: wafer mounting part

13: gas layer 70: vacuum pump

20: gas injection nozzle 71: pressure regulating valve

30: infrared lamp 80: drain valve

40: nitrogen and inert gas line W: wafer

50: cleaning liquid injection nozzle

The present invention relates to a single wafer cleaning apparatus and a cleaning method, and more particularly, to a single wafer cleaning apparatus and a cleaning method which prevents contaminants from being resorbed on the wafer surface by a process in an ozone gas atmosphere. .

In general, during the wafer manufacturing process, metal contaminants adhere to the surface of the wafer or foreign matter in the air is deposited in the form of particles. As a process for removing the metal contaminants and particles, a cleaning process using pure water or a chemical solution is used.

The wafer cleaning apparatus used in the cleaning process is largely classified into a batch cleaning process and a single sheet cleaning process. The batch cleaning apparatus is provided with a cleaning tank capable of processing 25 or 50 wafers at a time. The use of a batch cleaning device has the advantage that the top and bottom of the wafer can be cleaned at the same time and can process a large volume of wafers at the same time. However, in the batch cleaning apparatus, the size of the cleaning tank increases as the size of the wafer is larger than 300 mm, which increases the size of the cleaning apparatus and the amount of chemicals used. There is a possibility of cross contamination.

In recent years, single wafer cleaning apparatuses have attracted attention due to the large diameter of wafers. The single wafer cleaning apparatus fixes the wafer in a small chamber capable of processing a single wafer, and then rotates the wafer by a motor while flowing the chemical liquid or pure water through the nozzle on the wafer, and thus the chemical liquid or Pure water or the like is spread over the wafer to remove foreign substances. The single sheet cleaning apparatus has an advantage that the size of the apparatus is smaller than that of the batch cleaning apparatus and has a homogeneous cleaning effect.

However, in the conventional single wafer cleaning apparatus, the process was performed under atmospheric pressure, and thus, there was a limit in removing metal contaminants and particles adhering to the wafer surface and cleaning the wafer surface.

 The present invention is an improvement of the conventional single wafer cleaning apparatus and cleaning method, and an object thereof is to provide a single wafer cleaning apparatus and a cleaning method which perform wafer cleaning more effectively.

In order to achieve the above object, the present invention is a main body portion formed by combining the upper / lower portions are each formed in a dome shape and can be separated from each other; A wafer mounting unit installed at an approximately center in the main body to mount and horizontally rotate the wafer loaded into the main body; An ozone gas line for supplying ozone gas into the main body; A nitrogen and inert gas line for supplying nitrogen and an inert gas into the body portion; A plurality of upper and lower curved surfaces are formed in the main body, and the ozone gas, the nitrogen and the inert gas line are selectively supplied with the ozone gas, the nitrogen and the inert gas, and injected into the main body. Spray nozzles; A cleaning liquid spray nozzle spraying the cleaning liquid onto the wafer surface; And a vacuum pump for evacuating the gas inside the main body portion.

In addition, the present invention, in order to achieve the above object, a single wafer cleaning method using the above-described single wafer cleaning device, the step of loading the wafer to be cleaned in the wafer mounting portion; Injecting ozone gas into the body portion through a gas injection nozzle to make the inside of the body portion into an ozone atmosphere; Rotating the wafer by rotating the wafer mount; Supplying dilute hydrofluoric acid through a cleaning liquid jet nozzle to remove native oxide film and contaminants from the wafer surface; Discontinuing the supply of dilute hydrofluoric acid; Spraying ultrapure water onto the wafer surface through the cleaning liquid spray nozzle to remove the diluted hydrofluoric acid; Drying the wafer; Exhausting the ozone gas by depressurizing the inside of the main body to a vacuum by using a vacuum pump; Boosting the pressure inside the main body to atmospheric pressure by injecting nitrogen or an inert gas into the main body through the gas injection nozzle; And removing the wafer. The method also provides a wafer type wafer cleaning method comprising: a wafer;

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 disclosed below, but may be implemented in various forms. It is provided to give. Like numbers refer to like elements throughout.

FIG. 1 is a schematic cross-sectional view of a single wafer cleaning apparatus according to the present invention, and FIG. 2 is a schematic cross-sectional view of an upper cleaning liquid jet nozzle of the single wafer cleaning apparatus of FIG. 1 spaced apart from the outer circumference of the wafer.

1 and 2, the sheet type wafer cleaning apparatus according to the present invention includes a main body 10, a gas injection nozzle 20, an infrared lamp 30, a cleaning liquid injection nozzle 50, and a wafer mounting unit 60. And a vacuum pump 70.

The main body 10 is formed by dividing the upper portion 10_a and the lower portion 10_b. Each of the upper part 10_a and the lower part 10_b is formed in a dome shape, and the main body part 10 is formed by combining the upper part 10_a and the lower part 10_b. The single wafer cleaning method of the present invention proceeds in a state where the inside of the main body portion 10 is formed in an ozone atmosphere, wherein the pressure inside the main body portion 10 maintains a pressure slightly higher than atmospheric pressure. In addition, the step of changing the pressure inside the body portion 10 to a vacuum or atmospheric pressure is included. At this time, the dome shape provides a structure that can most stably withstand changes in pressure. The main body 10 is formed in a double structure including an outer main body 11 and an inner main body 12. A gas layer 13 is formed between the outer main body 11 and the inner main body 12 so that ozone gas, nitrogen, and an inert gas can be injected, so that the ozone gas having a uniform pressure inside the main body 10, Nitrogen, an inert gas, etc. can be injected.

The gas injection nozzles 20 are formed in plural on curved surfaces of the upper portion 10_a and the lower portion 10_b inside the body portion 10. Ozone gas, nitrogen and inert gas are selectively supplied to the gas layer 13 through the ozone gas line 21 and the nitrogen and inert gas line 40, and the ozone gas or nitrogen and the inert gas supplied to the gas layer 13 It is injected into the main body 10 through the gas injection nozzle (20).

A plurality of infrared lamps 30 are formed on the curved surface of the upper portion 10_a and the lower portion 10_b inside the main body 10. The infrared lamp 30 serves to dry the surface of the wafer W by irradiating the surface of the wafer W with infrared rays.

The cleaning liquid spray nozzle 50 sprays the cleaning liquid to clean the surface of the wafer (W). Here, the cleaning solution includes dilute hydrofluoric acid, dilute ammonia, ultrapure water, and SC1 (Standard Cleaning 1) cleaning solution. Here, SC1 cleaning liquid is ammonia (NH ₄ OH) aqueous solution of hydrogen peroxide (H ₂ O _2), the cleaning solution of strong alkali mixed solution of pure water. The cleaning liquid jet nozzle 50 includes an upper cleaning liquid jet nozzle 51 for injecting a cleaning liquid onto the upper surface of the wafer W, and a lower cleaning liquid jet nozzle 52 for injecting a cleaning liquid into the lower portion of the wafer W. The upper cleaning liquid injection nozzle 51 is advanced in the outer circumference of the wafer W when the cleaning liquid is injected, and is formed so as to retract out of the outer circumference of the wafer W when the cleaning liquid injection is completed. The lower cleaning liquid injection nozzle 52 sprays the cleaning liquid in a fixed state.

The wafer mounting unit 60 is installed inside the main body unit 10. The wafer mounting unit 60 is, for example, triangular in shape, and each triaxial end is formed to fix an edge portion of the wafer W. The wafer mounting unit 60 mounts the wafer W loaded into the main body 10 and is connected to a rotating means (not shown), for example, a motor to rotate the wafer W horizontally. However, the shape of the wafer mounting unit 60 and the wafer fixing method are not limited thereto, and may be modified as much as possible.

The vacuum pump 70 is controlled by the pressure regulating valve 71 to serve to exhaust the gas inside the main body 10 or to reduce the vacuum pressure.

Hereinafter, the operation of the single wafer cleaning apparatus having the above structure and the cleaning method using the same will be described.

3 is a flowchart of a single wafer cleaning method according to the present invention.

First, a process (S1) of loading the wafer W into the body part 10 through a body part inlet 14 located on the front of the body part 10 using a robot (not shown) is performed. . When the wafer W is loaded, ozone gas is supplied from the ozone gas line 21 to the gas layer 13. The ozone gas in the gas layer 13 is injected into the main body 10 through the gas injection nozzle 20. By injecting ozone gas, an oxide film is formed on the surface of the wafer W, thereby making the surface of the wafer W hydrophilic and preventing the particles from resorbing contaminants after the cleaning process.

As described above, a process (S3) of spraying dilute hydrofluoric acid onto the surface of the wafer (W) through the cleaning liquid injection nozzle 50 is performed while maintaining the inside of the main body portion 10 in an ozone atmosphere. When the dilute hydrofluoric acid is injected, the upper cleaning liquid injection nozzle 51 is advanced into the outer circumference of the wafer W. The upper cleaning liquid jet nozzle 51 sprays dilute hydrofluoric acid simultaneously onto the upper surface of the wafer W, and the lower cleaning liquid jet nozzle 52 simultaneously onto the lower surface of the wafer W.

When the dilute hydrofluoric acid is injected, the wafer mount unit 60 is rotated horizontally by a motor (not shown), and the wafer W fixed to the wafer mount unit 60 is also rotated. Diluted hydrofluoric acid injected onto the wafer W is cleaned while spreading evenly on the surface of the wafer W by the rotational force of the wafer, that is, the centrifugal force. When a predetermined amount of diluted hydrofluoric acid is injected, the cleaning liquid injection nozzle 50 stops the injection of the diluted hydrofluoric acid (S4). At this time, the upper cleaning liquid injection nozzle 51 is retracted out of the outer circumference of the wafer W. At this time, if the upper cleaning liquid jet nozzle 51 is not retracted out of the outer circumference of the wafer W, the dilute hydrofluoric acid remaining inside the upper cleaning liquid jet nozzle 51 falls on the wafer W, so that a water mark or the like is dropped. There is a concern that the cleaning may be uneven due to the formation of. In order to alleviate this concern, when spraying dilute hydrofluoric acid, the upper cleaning liquid injection nozzle 51 is advanced into the outer periphery of the wafer W. On the contrary, when the dilute hydrofluoric acid is not sprayed, the upper cleaning liquid injection nozzle 51 is advanced. Prevent dilute hydrofluoric acid from falling on the surface.

The spraying step S3 and the stopping step S4 of the dilute hydrofluoric acid may be repeated until the surface of the wafer W is completely cleaned.

Dilute hydrofluoric acid removes the native oxide film formed on the surface of the wafer W and removes metal contaminants. The surface of the wafer W cleaned by dilute hydrofluoric acid was hydrophobic. In the single wafer cleaning apparatus according to the present invention, since the cleaning process is performed in an ozone atmosphere, an oxide film is formed on the surface of the wafer W which is hydrophobic due to dilute hydrofluoric acid at the same time as the cleaning. Accordingly, the wafer W surface is exposed to the atmosphere at the same time as the cleaning process by dilute hydrofluoric acid is stopped to prevent contaminant particles from reattaching, and the wafer surface is converted to hydrophilic.

When the cleaning processes S3 and S4 by dilute hydrofluoric acid are completed, in order to remove the dilute hydrofluoric acid remaining on the surface of the wafer W, a step S5 of spraying ultrapure water is performed. Ultrapure water is supplied through the cleaning liquid injection nozzle (50). This is similar to the dilute hydrofluoric acid injection step S3. When the upper cleaning liquid injection nozzle 51 is advanced into the outer circumference of the wafer W and ultrapure water is injected onto the surface of the wafer W, the wafer is rotated by the wafer mounting portion 60. (W) Dilute hydrofluoric acid is removed from the wafer (W) surface while ultrapure water is spread throughout the surface.

After this process, the process of spraying dilute ammonia (S6) may further proceed. At this time, it can also wash using SC1 washing | cleaning liquid instead of dilution ammonia. The diluted ammonia and the SC1 cleaning liquid are sprayed through the cleaning liquid spray nozzle 50, and the process is the same as the diluted hydrofluoric acid spray process S3 or the ultrapure water spray process S5. When the dilute ammonia is sprayed (S6), the charge on the surface of the wafer (W) is converted to negative (-) to generate repulsive forces with particles having a normal negative charge, thereby preventing resorption. In addition, it is possible to remove particles that may remain.

After the step S6 of cleaning the surface of the wafer W with dilute ammonia or SC1 cleaning liquid, the steps S3 and S4 of cleaning with dilute hydrofluoric acid can be repeated. This is an optional step that allows the user to determine whether or not to proceed by looking at the cleaning progress of the wafer. When the step (S6) of cleaning the surface of the wafer (W) with dilute ammonia or SC1 cleaning liquid is completed, the step (S7) of removing the diluted ammonia or SC1 cleaning liquid from the surface of the wafer (W) using ultrapure water is performed. Also the same as step (S5) in which the dilute hydrofluoric acid is removed by ultrapure water.

When the above cleaning process is completed, the drying process S8 is started. Drying process S8 advances drying by centrifugal force by rotating a wafer by the rotation of the wafer mounting part 60. At this time, drying of the wafer W may be accelerated by injecting nitrogen or an inert gas through the cleaning liquid injection nozzle 50.

In the drying process S8, the infrared lamp 30 may be used to directly heat the wafer W to promote drying of the cleaning liquid and ultrapure water remaining on the surface of the wafer W. In this case, a plurality of infrared lamps 30 are formed on the curved surface of the upper portion 10_a and the lower portion 10_b inside the main body 10. If the heating temperature of the wafer W using the infrared lamp 30 is too high, damage to the surface of the wafer W is caused, so that the heat generation amount of the infrared lamp 30 is appropriately adjusted.

When the drying step (S8) is completed, a step (S9) of reducing the pressure in a vacuum state using a vacuum pump 70 to exhaust the ozone gas in the body portion 10 is performed. The vacuum pump 70 is controlled by the pressure control valve 71. When the ozone gas and the foreign matter inside the main body 10 are removed by the vacuum pump 70, nitrogen and an inert gas are injected into the main body 10 to extract the wafer W, thereby reducing the pressure of the main body 10. Step S10 of boosting to atmospheric pressure is performed.

Then, the cleaning process using the sheet type wafer cleaning apparatus and cleaning method according to the present invention is completed by taking out the wafer W through the main body portion inlet 14 using a robot (not shown).

In the above, the present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications are possible by those skilled in the art within the technical idea of the present invention. Is obvious.

According to the single wafer cleaning apparatus and the cleaning method according to the present invention, since the cleaning process is performed while maintaining an ozone atmosphere in a dome-shaped enclosed space, the hydrophobic wafer surface is hydrophilized by ozone without exposure directly to the atmosphere. As a result, resorption of contaminant particles can be prevented and a clean wafer surface can be obtained.

In addition, during cleaning, when the cleaning approaches the outer periphery of the wafer and the cleaning is completed, non-uniform cleaning due to the falling of the cleaning liquid can be prevented by using a cleaning liquid jet nozzle spaced out of the wafer outer periphery.

Claims (10)

Body parts each formed in a dome shape and formed by combining the upper and lower parts that can be separated from each other; A wafer mounting unit installed inside the main body to mount and rotate horizontally the wafer loaded into the main body; An ozone gas line for supplying ozone gas into the main body; A nitrogen and inert gas line for supplying nitrogen and an inert gas into the body portion; A plurality of upper and lower curved surfaces are formed in the main body, and the ozone gas, the nitrogen and the inert gas line are selectively supplied with the ozone gas, the nitrogen and the inert gas, and injected into the main body. Spray nozzles; A cleaning liquid spray nozzle spraying the cleaning liquid onto the wafer surface; And In the single wafer cleaning apparatus comprising: a vacuum pump for exhausting the gas inside the main body portion, The main body portion, the single wafer type cleaning device, characterized in that the outer body portion and the inner body portion is formed in duplicate so that a gas layer is formed between the outer body portion and the inner body portion. delete The method of claim 1, And an infrared lamp for promoting drying of the wafer, wherein the plurality of infrared lamps are formed on upper and lower curved surfaces inside the main body. The method of claim 1, The cleaning liquid injection nozzle An upper cleaning liquid injection nozzle for spraying a cleaning liquid on the upper surface of the wafer; And A lower cleaning liquid injection nozzle for spraying a cleaning liquid on the lower surface of the wafer; And the upper cleaning liquid injection nozzle approaches the outer circumference of the wafer when spraying the cleaning liquid, and is spaced out of the outer circumference of the wafer when the spraying of the cleaning liquid is stopped. The method of claim 1, The cleaning liquid is a single wafer cleaning apparatus, characterized in that the dilute hydrofluoric acid, dilute ammonia, ultrapure water and SC1 (Standard Cleaning 1) cleaning liquid. As a single wafer cleaning method using a single wafer cleaning apparatus according to claim 1, Loading a wafer to be cleaned into a wafer mount; Injecting ozone gas into the body portion through a gas injection nozzle to make the inside of the body portion into an ozone atmosphere; Rotating the wafer by rotating the wafer mount; Supplying dilute hydrofluoric acid through a cleaning liquid jet nozzle to remove native oxide film and contaminants from the wafer surface; Discontinuing the supply of dilute hydrofluoric acid; Spraying ultrapure water onto the wafer surface through the cleaning liquid spray nozzle to remove the diluted hydrofluoric acid; Drying the wafer; Exhausting the ozone gas by depressurizing the inside of the main body to a vacuum by using a vacuum pump; Boosting the pressure inside the main body to atmospheric pressure by injecting nitrogen or an inert gas into the main body through the gas injection nozzle; And Removing the wafer; Single wafer cleaning method comprising a. The method of claim 6, Drying the wafer comprises the step of supplying nitrogen or an inert gas through the cleaning liquid injection nozzle to promote the drying of the wafer. The method of claim 6, Drying the wafer comprises using an infrared lamp to facilitate drying of the wafer. The method of claim 6, After washing with ultrapure water to remove the diluted hydrofluoric acid Supplying diluted ammonia or SC1 cleaning liquid to clean the wafer; And Washing with ultrapure water to remove the diluted ammonia or SC1 cleaning liquid; Single wafer cleaning method comprising a further. The method of claim 6, Single wafer cleaning method characterized in that for repeating the step of supplying the diluted hydrofluoric acid and the step of stopping the supply of the diluted hydrofluoric acid.

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