JPH10223600A - Method and device for cleaning - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove foreign matters adhering to the surface of a semiconductor wafer, without breaking a wafer. SOLUTION: A cleaning device comprises a cleaning container 4 for receiving a cleaning solution 3 used for cleaning a semiconductor wafer 1 and a compressor 5 which pressurizes the cleaning solution 3 contained in the container 4. Particles 2 adhering to the wafer 1 are removed by activating the movement of molecules 3a of the cleaning solution 3 by pressurizing the solution 3 with a compressed N2 gas 6 by using the compressor 5, while the solution 3 is contained in the container 4 and the wafer 1 is dipped in the solution 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning technique for a semiconductor wafer in a semiconductor manufacturing technique, and more particularly to a cleaning method and an apparatus for improving the efficiency of removing foreign substances adhering to a semiconductor wafer while preventing damage to the semiconductor wafer.

[0002]

2. Description of the Related Art The technology described below studies the present invention,
Upon completion, they were examined by the inventor, and the outline is as follows.

[0003] In a semiconductor manufacturing process, NH ₄ OH (ammonium hydroxide) is used as a method of cleaning a semiconductor wafer to remove particles (foreign matter) attached to the semiconductor wafer.
H ₂ O ₂ (hydrogen peroxide) and H ₂ O cleaning method using a cleaning solution obtained by mixing (water) is known as.

In the cleaning method using this cleaning liquid,
In order to improve the particle removal efficiency, processing such as heating the cleaning liquid to a high temperature or applying ultrasonic waves is performed.

[0005] Regarding the semiconductor wafer cleaning technology, for example, “Monthly Seminar” published by Press Journal Inc.
Conductor World ", March 1995, February 20, 1995, pp. 88-95.

[0006]

However, in the above-described technique, when the cleaning liquid is heated, there is a problem that the etching amount in the film to be etched increases.

[0007] Further, when ultrasonic waves are applied to the cleaning liquid, there is a problem that the ultrasonic waves break fine patterns formed on the semiconductor wafer.

An object of the present invention is to provide a cleaning method and an apparatus for improving the efficiency of removing foreign substances adhering to a semiconductor wafer while preventing damage to the semiconductor wafer.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0010]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, in the cleaning method according to the present invention, a step of preparing a cleaning container containing a cleaning liquid for cleaning a semiconductor wafer; a step of dipping the semiconductor wafer in the cleaning liquid stored in the cleaning container; Pressurizing the cleaning liquid in which the semiconductor wafer is immersed in a cleaning container, and pressurizing the cleaning liquid to activate the movement of molecules of the cleaning liquid to remove foreign substances attached to the semiconductor wafer. Is what you do.

Thus, the motion of the molecules of the cleaning liquid can be activated, and the kinetic energy of the molecules of the cleaning liquid can be increased.

That is, since the movement of the molecules of the cleaning solution can be increased, the interaction between the molecules of the cleaning solution and the foreign molecules can be increased.

Therefore, the foreign matter can be moved, and as a result, the foreign matter can be removed from the semiconductor wafer.

In the cleaning method according to the present invention, the cleaning liquid is pressurized by gas.

Further, in the cleaning method according to the present invention, an inert gas is used as the gas.

Further, the cleaning apparatus according to the present invention has a cleaning container for storing a cleaning liquid for cleaning a semiconductor wafer, and pressurizing means for pressurizing the cleaning liquid stored in the cleaning container, wherein the cleaning container stores the cleaning liquid in the cleaning container. The cleaning liquid in which the semiconductor wafer is immersed is pressurized by the pressurizing means, thereby activating the movement of the molecules of the cleaning liquid to remove foreign substances attached to the semiconductor wafer.

[0018]

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

FIG. 1 is a conceptual view showing the structure of a cleaning apparatus according to an embodiment of the present invention.

The cleaning apparatus according to the present embodiment removes particles 2 (foreign matter) adhered to the semiconductor wafer 1 using the cleaning liquid 3 without performing high-temperature heating or application of ultrasonic waves.

The structure of the cleaning device will be described.
A cleaning container 4 containing a cleaning liquid 3 for cleaning the semiconductor wafer 1 and a compressor 5 serving as a pressurizing means for pressurizing the cleaning liquid 3 contained in the cleaning container 4 are provided. By using a compressor 5 and pressurizing the cleaning liquid 3 impregnated with the gas compressed by the compressor 5, the movement of the molecules 3 a of the cleaning liquid 3 is activated to remove the particles 2 attached to the semiconductor wafer 1. Things.

In this embodiment, the case where the pressurizing means is the compressor 5 for compressing a gas and the cleaning liquid 3 is pressurized by the gas compressed by the compressor 5 will be described.

Further, a case where an inert gas is used as the gas will be described. In the present embodiment, a case where an N ₂ gas 6 is used among the inert gases will be described.

Here, a gas supply unit 7 for supplying N ₂ gas 6 to the cleaning container 4 is connected via a gas supply system 8, and a compressor 5 is provided in the gas supply system 8. .

The supply of the N ₂ gas 6 to the cleaning container 4 is performed in a clearance 4 b formed above the cleaning liquid 3 in the cleaning container 4.

That is, the N ₂ gas supplied from the gas supply unit 7
The gas 6 is compressed by the compressor 5, and the pressure at this time is used to apply pressure to the cleaning liquid 3 by the N ₂ gas 6.

The cleaning container 4 can be removed when the semiconductor wafer 1 is carried in and out and when the cleaning liquid 3 is supplied, and can be attached during the cleaning process.
A detachable lid member 4a capable of sealing the inside is provided.

Since a large pressure is also applied to the cover member 4a during the cleaning process, it is preferable to use screws or the like to fix the cover member 4a.

The cleaning liquid 3 in the present embodiment is
It is a mixture of NH ₄ OH (ammonium hydroxide), H ₂ O ₂ (hydrogen peroxide) and H ₂ O (water).

This is because the ammonia of NH ₄ OH constituting the cleaning liquid 3 has an etching action and an action of preventing the substance to be etched from being reattached at this time. It is preferable to use a mixture.

However, the cleaning liquid 3 is not limited to this mixed liquid, but may be any other chemical using hydrofluoric acid, for example, as long as it is used in the cleaning step of the semiconductor wafer 1. Good.

The gas used in the present embodiment is N ₂
Although the gas 6 is used, the gas may be another inert gas such as an argon gas, or may be dry air other than the inert gas.

However, it is preferable to use, as the gas, an inert gas containing a very small amount of impurities.

The cleaning container 4 is provided with a pressure gauge 9 for detecting the internal pressure.

The cleaning method according to the present embodiment will be described.

The cleaning method uses the cleaning apparatus of the present embodiment, and the cleaning liquid 3 (a mixed liquid of NH ₄ OH, H ₂ O ₂ and H ₂ O) in which the semiconductor wafer 1 is immersed. Is applied to remove particles 2 (foreign matter) attached to the semiconductor wafer 1.

Therefore, also in the above-mentioned cleaning method, a case will be described in which the cleaning liquid 3 is pressurized with a gas and the gas uses an N ₂ gas 6 which is an example of an inert gas.

First, a cleaning liquid 3 for cleaning the semiconductor wafer 1
Prepare a washing container 4 in which is stored.

Subsequently, the lid member 4a of the washing container 4 is opened,
A predetermined amount of the cleaning liquid 3 is supplied into the cleaning container 4.

At this time, the clearance 4b
Is supplied to such an extent that is formed.

That is, in the cleaning container 4, the cleaning liquid 3 is supplied to such a depth that the cleaning liquid 3 does not reach the location where the gas supply system 8 is connected.

Thus, when the supply of the cleaning liquid 3 is completed, a gap 4b is formed in the cleaning container 4 above the cleaning liquid 3, as shown in FIG.

However, the volume of the gap 4b is equal to the N ₂ gas 6
Any size can be used as long as it can supply the same.

Subsequently, the semiconductor wafer 1 is carried into the cleaning container 4, and the semiconductor wafer 1 is immersed in the cleaning liquid 3 contained in the cleaning container 4.

Thereafter, the cover member 4a of the washing container 4 is securely attached by screws so as not to come off.
Keep the inside closed.

Further, N ₂ gas 6 is sent from the gas supply unit 7 to the gap 4 b of the cleaning container 4 via the gas supply system 8, and the pressure inside the cleaning container 4 is checked while the pressure of the cleaning container 4 is checked by the pressure gauge 9. The N ₂ gas 6 is continuously sent until the pressure reaches a predetermined pressure.

After the pressure in the cleaning container 4 reaches a predetermined pressure, the cleaning liquid 3 in which the semiconductor wafer 1 is immersed in the cleaning container 4 is pressurized.

That is, after the pressure in the cleaning container 4 reaches a predetermined pressure, pressure is applied to the gap 4b of the cleaning container 4 using the compressor 5 installed in the gas supply system 8.

At this time, since the cleaning container 4 is in a sealed state, the cleaning liquid 3 is filled with the N ₂ gas 6 filled in the gap 4b.
Can be pressurized.

Thus, the kinetic energy of the molecules 3a in the pressurized cleaning liquid 3 increases.

That is, the pressurized NH ₄ O
The movement of each molecule 3a in H, H ₂ O ₂ and H ₂ O is activated, whereby the kinetic energy of each molecule 3a is increased and each molecule 3a moves actively.

As a result, the molecule 3a and the semiconductor wafer 1
Interaction with particles 2 (foreign matter) such as particles such as silicon and carbon attached to the semiconductor wafer 1 becomes large, whereby the particles 2 attached to the semiconductor wafer 1 can be moved.

When the cleaning liquid 3 is pressurized by the N ₂ gas 6, the pressure inside the cleaning container 4 is not set to a predetermined pressure, but the compressor 5 is pressurized from the beginning. The N ₂ gas 6 is supplied to the gap 4 b of the cleaning container 4,
Thereby, the cleaning liquid 3 may be pressurized.

According to the cleaning method and apparatus of the present embodiment, the following operational effects can be obtained.

That is, the semiconductor wafer 1 in the cleaning container 4
By pressurizing the cleaning liquid 3 impregnated with, the movement of the molecules 3a of the cleaning liquid 3 can be activated.

That is, by pressurizing the cleaning liquid 3,
The kinetic energy of the molecules 3a of the cleaning liquid 3 can be increased.

As a result, the movement of the molecules 3a of the cleaning liquid 3 can be increased, so that the interaction between the molecules 3a of the cleaning liquid 3 and foreign particles, that is, the particles 2, can be increased.

As a result, since the particles 2 can be moved from the semiconductor wafer 1, the particles 2 can be removed from the semiconductor wafer 1.

Therefore, it is possible to remove the particles 2 adhered to the semiconductor wafer 1 while preventing the fine pattern formed on the semiconductor wafer 1 from being damaged.
The removal efficiency of the particles 2 can be improved.

That is, since the semiconductor wafer 1 is washed without heating the semiconductor wafer 1 to a high temperature and without applying ultrasonic waves, the amount of film scraping during etching or the fine pattern formed on the semiconductor wafer 1 is increased. The removal efficiency of the particles 2 attached to the semiconductor wafer 1 can be improved while preventing damage to the semiconductor wafer 1.

Thus, the yield of the semiconductor wafer 1 in the cleaning step can be improved.

Although the invention made by the inventor has been specifically described based on the embodiments of the present invention, the present invention is not limited to the embodiments of the invention, and does not depart from the gist of the invention. It is needless to say that various changes can be made.

For example, in the cleaning method and apparatus described in the above embodiment, the case where the cleaning liquid 3 is pressurized by gas (N ₂ gas 6) has been described, but the method of pressurizing the cleaning liquid 3 is not limited to this. Alternatively, other pressing methods such as various pressing mechanisms may be used.

Here, the cleaning apparatus according to another embodiment shown in FIGS. 2 and 3 pressurizes the cleaning liquid 3 by using a pressurizing mechanism, and is a movable sealing device capable of sealing the inside of the cleaning container 4. The member 4c is used. The sealing member 4 c is, for example, a plate-shaped member, and has an outer shape enough to lightly contact the inner peripheral wall of the cleaning container 4.

That is, the surface of the cleaning liquid 3 is pressurized by the sealing member 4c, whereby the cleaning liquid 3 is pressurized.

In the cleaning apparatus shown in FIG. 2, the pressurizing means includes a sealing member 4c for sealing the cleaning container 4, a screw member 10 serving as a load applying member for applying a load to the sealing member 4c, and a cleaning container. 4 and a load applying member supporting member 11 that supports the screw member 10. The load applying member support member 11 is, for example, a support member such as a plate or a prism.

When the screw member 10 is rotated in a predetermined direction, the load applying member supporting member 11 that is screw-coupled to the screw member 10 is attached to the cleaning container 4, so that the screw member 10 can be moved. it can.

That is, by rotating the screw member 10 in a predetermined direction, the screw member 10 is pressed against the sealing member 4c, and the surface of the cleaning liquid 3 can be pressurized by the sealing member 4c.

In the cleaning apparatus shown in FIG. 3, the pressurizing means includes a sealing member 4c for sealing the cleaning container 4, an elastic member 12 serving as a load applying member for applying a load to the sealing member 4c, and a cleaning container. 4 and a load applying member supporting member 11 that supports the elastic member 12.

Here, the elastic member 12 is, for example, a spring member having a high spring constant and applies a desired load to the sealing member 4c. The member 4c presses the surface of the cleaning liquid 3.

In the cleaning apparatus according to the other embodiment shown in FIGS. 2 and 3, the same operation and effect as those of the cleaning apparatus described in the above embodiment can be obtained.

Further, as the load applying member, not only the elastic member 12 such as the screw member 10 or the spring member but also a gear member may be used.

[0073]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1). By pressurizing the cleaning liquid in which the semiconductor wafer is immersed in the cleaning container, it becomes possible to activate the movement of molecules of the cleaning liquid. Thereby, the kinetic energy of the molecules of the cleaning liquid can be increased, and the movement of the molecules of the cleaning liquid can be increased.

As a result, the interaction between the molecules of the cleaning liquid and the foreign matter molecules can be increased, and the foreign matter can be removed from the semiconductor wafer.

(2). According to the above (1), since the semiconductor wafer is cleaned without heating the semiconductor wafer to a high temperature and without applying ultrasonic waves, the amount of film scraping at the time of etching is increased or a fine pattern formed on the semiconductor wafer is damaged. And the efficiency of removing foreign matter (particles) attached to the semiconductor wafer can be improved.

(3). The yield of semiconductor wafers can be improved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating an example of an embodiment of a structure of a cleaning apparatus according to the present invention.

FIG. 2 is a conceptual view showing the structure of a cleaning apparatus according to another embodiment of the present invention.

FIG. 3 is a conceptual diagram illustrating a structure of a cleaning apparatus according to another embodiment of the present invention.

[Explanation of symbols]

1 semiconductor wafer 2 particle (foreign matter) 3 washing solution 3a molecules 4 washing container 4a lid member 4b clearance 4c sealing member 5 compressor (pressurizing means) 6 N ₂ gas (gas) 7 gas supply part 8 gas supply system 9 pressure gauge Reference Signs List 10 Screw member (load applying member) 11 Load applying member support member 12 Elastic member (load applying member)

Claims (9)

[Claims] 1. A cleaning method for removing foreign matter adhering to a semiconductor wafer, comprising: preparing a cleaning container containing a cleaning liquid for cleaning the semiconductor wafer; A step of immersing the semiconductor wafer; and a step of pressurizing the cleaning liquid in which the semiconductor wafer is immersed in the cleaning container. By pressurizing the cleaning liquid, the movement of the molecules of the cleaning liquid is activated. A cleaning method, wherein the foreign matter attached to the semiconductor wafer is removed. 2. The cleaning method according to claim 1, wherein the cleaning liquid is pressurized with a gas. 3. The cleaning method according to claim 2, wherein an inert gas is used as the gas. 4. The cleaning method according to claim 1, wherein the surface of the cleaning liquid is pressurized by a sealing member for sealing the cleaning container to pressurize the cleaning liquid. 5. A cleaning apparatus for removing foreign matter adhering to a semiconductor wafer, comprising: a cleaning container for storing a cleaning liquid for cleaning the semiconductor wafer; and a pressurizing unit for pressurizing the cleaning liquid stored in the cleaning container. By pressurizing the cleaning liquid contained in the cleaning container and impregnated with the semiconductor wafer by the pressurizing means, the movement of the molecules of the cleaning liquid is activated and the cleaning liquid adheres to the semiconductor wafer. A cleaning device for removing foreign matter. 6. The cleaning apparatus according to claim 5, wherein the pressurizing means is a compressor for compressing a gas, and the cleaning liquid is pressurized by the gas compressed using the compressor. Cleaning equipment. 7. The cleaning device according to claim 6, wherein an inert gas is used as the gas. 8. The cleaning apparatus according to claim 5, wherein the pressurizing means is attached to the cleaning container, a sealing member for sealing the cleaning container, a load applying member for applying a load to the sealing member. And a load applying member supporting member for supporting the load applying member. 9. The cleaning device according to claim 8, wherein the load applying member is a screw member or an elastic member.