JP2000262995A - Aerosol cleaning apparatus and multi-stage cleaning method using the same - Google Patents

Abstract

(57) [Problem] To improve a cleaning performance and a throughput by enabling a multi-step cleaning by a single series of cleaning operations. SOLUTION: When cleaning the surface of a wafer 10 with an aerosol 24 blown out from an aerosol nozzle 20, it is possible to switch cleaning parameters during a series of cleaning operations. And multi-step cleaning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aerosol cleaning apparatus and a multi-step cleaning method using the same.
An aerosol cleaning apparatus, which can be used in combination with a plurality of types of cleaning in a series of cleaning operations and is suitable for use in cleaning the surface of a substrate such as a semiconductor wafer, and Related to the multi-stage cleaning method.

[0002]

2. Description of the Related Art Fine particles (particles) and dirt on the surface of a semiconductor wafer or the surface of a liquid crystal (LCD) or a solar cell in an LSI manufacturing process greatly reduce the yield of a final product. Surface cleaning is very important.

Therefore, various surface cleaning methods have been conventionally proposed. In the case of semiconductor production, for example, pure water cleaning using ultrasonic waves and chemical solutions (for example, ammonia hydrogen peroxide solution and sulfuric acid peroxide solution) in pure water are proposed. A wet cleaning method is used in which an object to be cleaned is immersed in a solution to which a (hydrogen solution) is added, and the object is cleaned.

However, this type of wet cleaning system is
There is a problem that the installation area of various facilities is large, and waste liquid treatment is required.

On the other hand, as a dry cleaning method using no liquid, there is dry cleaning using a chemical reaction by adding a gas, but there is a problem that contaminants on particles cannot be removed.

Further, it has been considered that particles such as dry ice, ice, and solid argon are made to collide with the surface of the object to be cleaned to remove particles. The surface may be damaged, and when dry ice is used, there is a problem of impurity contamination since dry ice itself is contaminated, especially in a commercial product using waste gas from steel or petroleum refinery.

On the other hand, Japanese Unexamined Patent Publication No.
And the method described in JP-A-6-295895, in which an aerosol containing argon solid fine particles (referred to as an argon aerosol) is collided in a reduced-pressure, zero-atmosphere atmosphere to clean the surface, the above problem does not exist. .

FIG. 1 is a pipeline diagram showing the overall structure of an example of a wafer cleaning apparatus using this argon aerosol, and FIG. 2 is a plan view thereof.

In this example, the argon gas and the nitrogen gas, the flow rates of which are controlled by the mass flow controllers 30 and 32, pass through a filter 34 and then enter, for example, a heat exchanger 38 using a helium (He) cryo refrigerator 36. After being cooled in the aerosol nozzle 20, the aerosol 24 is sprayed from a large number of fine nozzle holes 22 opened in the aerosol nozzle 20 into a cleaning chamber 42 for wafer cleaning, which is evacuated by the vacuum pump 40.

The wafer 10 is placed on a process hand (also referred to as an XY scan stage) 46 which is scanned in the X-axis direction and the Y-axis direction by a wafer scanning mechanism 44, and the entire surface of the wafer can be cleaned.

The acceleration nozzle 56 is used to improve the cleaning power.
Is supplied to the acceleration nozzle 56 via the mass flow controller 52 and the filter 54, and nitrogen gas (referred to as an acceleration gas 58) blown out from the nozzle hole is ejected from the aerosol nozzle 20. The aerosol 24 is accelerated.

For the purpose of preventing particles from re-adhering to the wafer surface, nitrogen gas flowing from one end (left end in FIG. 2) of the cleaning chamber 42 through the mass flow controller 62 and the filter 64 is used as a purge gas 66. Cleaning room 42
It is also considered to be supplied inside.

As shown in FIG. 2, the two wafers 10 in the cassette chamber 70 which are evacuated to a vacuum for loading the wafers 10 stored in the cassette 72 from the outside of the apparatus, which are provided for two cassette exchanges, The gate valve 74 is moved by a robot hand 86 attached to the tip of a robot arm 84 of a vacuum transfer robot (called a vacuum robot) 82 provided in a robot chamber (also called a transfer chamber) 80 for handling the wafer 10. , 76 to transfer the wafer 10 to the cleaning chamber 42
0 is transferred onto the process hand 46.

The wafer 10 carried on the process hand 46 driven by the wafer scanning mechanism 44 is scanned in the Y-axis direction and the X-axis direction below the aerosol nozzle 20.

The wafer 10 whose entire surface has been cleaned in this way is returned to the cassette chamber 70 by following the path carried into the buffer chamber 90 in reverse.

The cleaning ability of such an argon wafer cleaning apparatus is evaluated based on the cleaning power (impurity removal rate) and the number of reattachments of impurities. As shown in FIG. 3, the cleaning parameters for determining the cleaning performance include an argon gas flow rate, a nitrogen gas flow rate, a purge gas flow rate, an acceleration gas flow rate, a nozzle temperature, a scanning method (Y-axis cleaning as shown in FIG. 4, or
(X-axis cleaning as shown in FIG. 5), etc., and the setting is made by a process recipe. Also, the number of cleanings of the cleaning recipe of the teaching (parameter setting tab) (for example, in the Y-axis cleaning shown in FIG. 4,
(One round trip in the X-axis direction, two times, going and returning, and in the X-axis cleaning shown in FIG. 5, once after idling, returning once in the Y-axis direction.)
Make the settings for

In FIG. 3, the cryo frequency is set in accordance with the flow rate of the argon gas. Parameters.

Next, the aerosol 24 is generated according to the cleaning parameters set in the recipe, and cleaning is performed.

Normally, in an argon wafer cleaning apparatus, particles having a strong adhesive force are removed by accelerated cleaning using an accelerating gas 58 (the cleaning force is strong, but there are many re-adhesions), and a particle having a weak adhesive force or accelerated cleaning is used. The particles re-adhered by the above are removed by ordinary cleaning using a small amount of accelerating gas (the cleaning ability is weak, but the re-adhesion is small). Therefore, two types of cleaning, that is, accelerated cleaning and normal cleaning, are performed on one wafer.

FIG. 6 shows an example of the relationship between the cleaning chamber pressure and the impurity removal rate when a wafer to which impurities are adhered by means of a 0.2 μm alumina slurry is cleaned by changing the flow rates of an acceleration gas and a purge gas.

[0021]

However, conventionally,
In order to perform two types of cleaning, a series of parameter settings and a cleaning operation must be performed in two steps, and there is a problem in throughput.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to make it possible to perform a multi-stage cleaning by combining a plurality of types of cleaning having different cleaning parameters in a series of cleaning operations. I do.

[0023]

SUMMARY OF THE INVENTION The present invention provides an aerosol cleaning apparatus for cleaning the surface of an object to be cleaned with aerosol blown out from an aerosol nozzle, by enabling switching of cleaning parameters during a series of cleaning operations. This has solved the above-mentioned problem.

Further, in the aerosol cleaning device, a plurality of types of cleaning having different cleaning parameters are combined to perform multi-stage cleaning in a series of cleaning operations.

In addition, the plurality of types of cleaning include accelerated cleaning and normal cleaning.

[0026]

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

In this embodiment, since the cleaning parameters are switched during a series of cleaning operations, the number of times of cleaning switching is added to the cleaning parameters as shown in FIG. Acceleration gas flow 2 is added.

At the time of cleaning, these additional cleaning parameters are set in a recipe. Then, after the cleaning frequency reaches the cleaning switching frequency, the purge gas flow rate 1 of the cleaning parameter is changed to the purge gas flow rate 2, and the acceleration gas flow rate 1 is changed to the acceleration gas flow rate 2. Therefore, combined cleaning of accelerated cleaning and normal cleaning can be performed by one series of cleaning operations.

The cleaning parameters can be set, for example, as follows.

Argon gas flow: 60 [l / m] Nitrogen gas flow: 6 [l / m] Purge gas flow 1: 30 [l / m] Purge gas flow 2: 150 [l / m] Acceleration gas flow 1: 100 [l / m] 1 / m] Accelerated gas flow rate 2: 30 [l / m] Nozzle temperature: 92 [K] Number of times of washing change: 1 [times]

The cleaning recipe is set as follows by setting the teaching parameters.

Y cleaning_number of cleaning: 2 [times]

Here, the reason why the purge gas flow rate 1 during the accelerated cleaning is set to be much smaller than the purge gas flow rate 2 during the normal cleaning is to prevent the pressure in the cleaning chamber 42 from increasing and to increase the cleaning power. It is to strengthen.

An aerosol is prepared by controlling the argon gas flow rate and the nitrogen gas flow rate according to the recipe settings, and the number of times of Y cleaning—the number of cleanings: the first time, the accelerated cleaning is performed using the purge gas flow rate 1 and the acceleration gas flow rate 1. Done, Y cleaning _
Number of cleanings: In the second cleaning, normal cleaning is performed by switching to purge gas flow rate 2 and acceleration gas flow rate 2.

In the above description, accelerated cleaning is performed first, and then normal cleaning is performed. However, the type, order, and combination of cleaning are not limited to this. According to the object to be cleaned, it is possible to perform a combination of strong cleaning corresponding to rubbing and weak cleaning corresponding to rinsing. The type of cleaning and the number of times of switching are not limited to those in the above-described embodiment, and three or more types of cleaning can be performed by switching two or more times, or two types of cleaning can be repeatedly performed.

In the above embodiment, the present invention
Although the present invention has been applied to cleaning of semiconductor wafers, the application of the present invention is not limited to this, and other objects to be cleaned such as semiconductor masks, flat panel substrates, magnetic disk substrates, and flying head substrates can be used. Obviously, cleaning is equally applicable.

[0037]

According to the present invention, in a single series of cleaning operations, a plurality of types of cleaning with different cleaning parameters can be combined to perform multi-stage cleaning. Therefore, a single series of cleaning operations. The cleaning performance in is improved. In addition, the parameter setting and the cleaning operation have to be performed a plurality of times in order to obtain the same cleaning performance in the past.

[Brief description of the drawings]

FIG. 1 is a pipeline diagram showing an overall configuration of an example of an aerosol-based wafer cleaning apparatus to which the present invention is applied.

FIG. 2 is a plan view of the same.

FIG. 3 is a table showing an example of conventional cleaning parameters.

FIG. 4 is a plan view showing a scan state during Y-axis cleaning, which is one of the cleaning methods.

FIG. 5 is a plan view showing a scan state during X-axis cleaning.

FIG. 6 is a diagram showing an example of a relationship between a cleaning chamber pressure and an impurity removal rate when the flow rates of an acceleration gas and a purge gas are used as parameters;

FIG. 7 is a table showing an example of cleaning parameters according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Wafer (object to be cleaned) 22 ... Aerosol nozzle 24 ... Aerosol 36 ... Refrigerator 30, 32, 52, 62 ... Mass flow controller 40 ... Vacuum pump 42 ... Cleaning chamber 44 ... Wafer scanning mechanism 46 ... Process hand 56 ... Acceleration nozzle 58 ... Acceleration gas 66 ... Purge gas

Claims (3)

[Claims] 1. An aerosol cleaning apparatus for cleaning a surface of an object to be cleaned with aerosol blown out from an aerosol nozzle, wherein a cleaning parameter can be changed during a series of cleaning operations. 2. A multi-stage cleaning of an aerosol cleaning apparatus, wherein a plurality of types of cleaning with different cleaning parameters are combined and cleaned in a series of cleaning operations using the aerosol cleaning apparatus according to claim 1. Method. 3. The method according to claim 2, wherein said plurality of types of cleaning include accelerated cleaning and normal cleaning.