JP5039457B2 - Substrate cleaning device - Google Patents

Description

The present invention relates to a substrate cleaning apparatus for cleaning a bevel portion of a substrate such as a semiconductor wafer.

In the photolithography process in the manufacture of semiconductor devices, a resist coating process for applying a resist solution as a coating liquid on a substrate such as a semiconductor wafer to form a resist film, and a pre-baking process for heating the substrate after the coating process ( PAB), an exposure process for exposing the resist film to a predetermined pattern, a post-exposure baking process (PEB) for promoting a chemical reaction in the resist film after exposure, a development process for developing the exposed resist film, etc. A predetermined resist pattern is formed on the substrate to be processed.
Among these, the processes other than the exposure process are performed by the coating and developing apparatus, and the substrate is exchanged with the exposure apparatus that performs the exposure process.

In recent years, circuit patterns of semiconductor devices have rapidly become thinner, finer, and more highly integrated, and accordingly, it has become necessary to improve exposure resolution performance. Therefore, while development of exposure technology using extreme ultraviolet light (EUVL) or fluorine dimer (F ₂ ) is being promoted, for example, exposure technology using argon fluoride (ArF) or krypton fluoride (KrF) has been improved. In order to improve resolution performance, a method of performing exposure in a state where a liquid layer that transmits light is formed on the surface of a substrate (hereinafter referred to as immersion exposure) is often used. This exposure technique is a technique in which a lens and a semiconductor wafer are filled with a liquid such as pure water, and light is transmitted therethrough. For example, the ArF wavelength of 193 nm is 134 nm in pure water. We are using.
A substrate processing method for performing the immersion exposure processing is described in Patent Document 1.
JP 2006-49757 A

  By the way, in the photolithography process, a resist film is formed on the entire surface of the semiconductor wafer in the resist film forming process before the exposure process. Since the resist film formed on the peripheral edge of the wafer is unnecessary, the resist film on the peripheral edge of the wafer is removed in the edge remover unit after the resist film is formed.

  However, the processing in the edge remover unit is intended to remove a resist in a predetermined area on the wafer surface in the peripheral edge of the wafer, and is formed on a bevel portion (wafer end surface and its peripheral inclined portion) that is a substrate end. The resist film was not sufficiently removed. In that case, the resist film remains on the bevel portion in a state where it can be easily peeled off.When the resist film is peeled off, it becomes a foreign substance such as a particle.In particular, in the immersion exposure process, the foreign substance moves in the wafer surface in the liquid and the resolution performance is improved. There was a problem of getting worse.

Further, after the pattern etching with the etching apparatus, a process of removing the resist film used for the mask is performed, but the removed deposit remains in the bevel portion, and contamination by the deposit in the subsequent photolithography process. There was a problem that occurred.
In that case, there is a problem that it leads to a defect of the semiconductor device and causes a decrease in yield.

The present invention has been made under the circumstances as described above, and by cleaning the bevel portion of the substrate , it is possible to prevent the occurrence of contamination due to foreign matters generated at the bevel portion of the substrate and suppress the decrease in yield. An object of the present invention is to provide a substrate cleaning apparatus capable of performing the above.

In order to solve the above-described problems, a substrate cleaning apparatus according to the present invention is a substrate cleaning apparatus that cleans a bevel portion of a substrate, holds the substrate in a substantially horizontal posture, and can freely rotate the substrate about a vertical axis. And a substrate holding means, and the cleaning liquid is ejected laterally and tangentially to the bevel portion of the substrate held by the substrate holding means and rotating at a predetermined rotational speed, in the direction opposite to the rotation direction of the substrate. A cleaning liquid ejecting means; a suction means provided around the cleaning liquid ejecting means, for sucking in a side and tangential direction with respect to the bevel portion of the substrate and from a direction opposite to the rotation direction of the substrate; and the cleaning liquid ejecting The means is characterized in that vapor or aerosol-like cleaning liquid is jetted from the side to the bevel portion of the substrate, and the suction means sucks the atmosphere near the tip of the cleaning liquid jetting means.

With this configuration, the cleaning liquid can be directly applied to the rotating bevel portion of the substrate, so that the resist film and foreign matter on the bevel portion of the substrate can be effectively removed.
In particular, since the cleaning liquid is in a vapor state, it effectively penetrates into the resist film formed on the bevel portion of the substrate and the resist film is easily peeled off. The cleaning liquid is directly applied to the substrate bevel portion at a predetermined pressure. Therefore, the resist film can be easily peeled off.
Therefore, in subsequent substrate processing, contamination due to foreign matters attached to the bevel portion of the substrate can be prevented, and a decrease in yield can be suppressed.

It is preferable that the apparatus further includes a surface cleaning unit that supplies the cleaning liquid to the surface of the substrate that is held by the substrate holding unit and rotates at a predetermined rotation speed.
By configuring in this way, it is possible to wash away the cleaning liquid and foreign matters adhering to the substrate surface when cleaning the bevel portion of the substrate.

According to the present invention, by cleaning the bevel portion of the substrate , it is possible to obtain a substrate cleaning apparatus that can prevent the occurrence of contamination due to the foreign matter generated in the bevel portion of the substrate and suppress the yield reduction. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a coating and developing apparatus 100 including a substrate cleaning apparatus according to the present invention.
As shown in FIG. 1, the coating and developing apparatus 100 includes, for example, a cassette station 20 that loads and unloads 25 wafers W (substrates to be processed) from the outside in units of cassettes, and loads and unloads wafers W to and from the cassette C. A processing station 30 in which a plurality of processing units for performing predetermined processing in a single wafer type in the photolithography process are arranged in multiple stages, and provided adjacent to the processing station 30 to perform immersion exposure processing. It has a configuration in which an interface unit 40 that transfers a wafer to and from the immersion exposure apparatus 50 is integrally connected.

  In the coating and developing apparatus 100, in the processing station 30 that has received the wafer W from the cassette station 20, the wafer W is first transported along the arrow A and subjected to resist coating processing, pre-baking processing, and the like. Next, the wafer W is subjected to exposure processing by the immersion exposure apparatus 50 via the interface unit 40, and then delivered to the processing station 30 via the interface unit 40 again. The exposed wafer W is transported along the arrow B, and post exposure baking processing, development processing, and the like are sequentially performed to form a predetermined resist pattern on the wafer W.

The substrate cleaning apparatuses 1A and 1B according to the present invention are provided in, for example, the processing station 30 and the interface unit 40 as shown in FIG.
The substrate cleaning apparatus 1A provided in the interface unit 40 cleans the bevel part (wafer end part) of the wafer W on which a resist film is formed as a pre-process transferred to the exposure apparatus 50.
In addition, the substrate cleaning apparatus 1B provided in the processing station 30 applies a bevel portion (wafer edge) to the wafer W transferred from the etching apparatus (not shown) to the coating and developing apparatus 100 before the photolithography process in the coating and developing apparatus 100. Part).
The substrate cleaning apparatuses 1A and 1B have the same apparatus configuration, but a similar apparatus may be provided on the etching apparatus side to perform bevel portion cleaning after the etching process.

The substrate cleaning apparatuses 1A and 1B will be described with reference to FIG.
The substrate cleaning apparatuses 1A and 1B include a spin chuck 2 (substrate holding means) that holds the wafer W in a substantially horizontal posture as shown in the figure, and the spin chuck 2 is driven by a drive unit 3 disposed at the base end portion thereof. It is configured to be rotatable around the vertical axis and to be able to move up and down.
Further, the negative pressure generated by the decompression device 4 acts on the dish-shaped chuck portion formed at the upper end portion through a conduction tube (not shown) formed in the shaft of the spin chuck 2, and thereby the wafer W Is vacuum-adsorbed at the upper end of the spin chuck 2.
Further, around the spin chuck 2, a cup member 5 which is a container provided to accommodate the spin chuck 2 is provided. After collecting the cleaning liquid used for cleaning the bevel portion of the wafer W in the container, It is comprised so that it can drain from the drain pipe 6.

Further, around the wafer W held by the spin chuck 2, one or a plurality (two in the figure) of cleaning liquid spraying units 7 (cleaning liquid spraying means) for spraying the cleaning liquid toward the beveled portion of the wafer W are provided. Is provided. The cleaning liquid injection unit 7 includes a pure water supply unit 8 that supplies pure water as a cleaning liquid, and a pressurization unit 9 that pressurizes the pure water supplied from the pure water supply unit 8 with N ₂ gas and jets the pure water. The heater 10 that heats pure water pressurized by the pressurizing unit 9 to form a vapor, and the inner peripheral edge formed on the upper end of the cup member 5 by the vaporized cleaning liquid heated by the heater 10 The nozzle 11 for injecting toward the bevel part W1 from 5a vicinity is provided.

As shown in the plan view of FIG. 3, the nozzle 11 of the cleaning liquid ejecting unit 7 is disposed on the side of the wafer W, and is disposed in a normal direction to the bevel portion W <b> 1 (a direction perpendicular to a tangent to the circumference of the wafer W). Alternatively, they are arranged in the tangential direction of the circumference of the wafer W as shown in the plan view of FIG. Thereby, it is possible to directly apply the vapor-like cleaning liquid to the bevel portion W1, and the resist film on the bevel portion W1 can be effectively removed.
The nozzle 11 may be provided with a vacuum mechanism 15 around the nozzle 11 as shown in FIG. The vacuum mechanism 15 is, for example, a suction unit 16 including a suction pump, a recovery mechanism, and the like, and a suction pipe 16 that is provided around the nozzle 11 and sucks the atmosphere near the tip of the nozzle 11 by the suction force of the suction unit 16. With. By providing this vacuum mechanism 15, the cleaning liquid scattered on the bevel portion W <b> 1 can be collected, and the re-attachment of the cleaning liquid already used for cleaning to the wafer W can be prevented.
Further, when the nozzle 11 is arranged in the tangential direction of the circumference of the wafer W, as shown in FIG. 4, if the cleaning liquid is sprayed in the direction opposite to the rotation direction of the wafer W, the cleaning pressure for the bevel portion W1 is improved. preferable.

Further, as shown in FIG. 2, the wafer W held on the spin chuck 2 is sprayed in the form of vapor onto the bevel W1 by the cleaning liquid sprayer 7 and attached to the surface of the wafer W after use. In order to wash away the cleaning liquid, a surface cleaning unit 12 (surface cleaning means) is provided.
The surface cleaning unit 12 includes a nozzle 13 for discharging a cleaning liquid such as pure water onto the surface of the wafer W, and a cleaning liquid supply unit 14 for supplying the cleaning liquid to the nozzle 13.

Subsequently, a process of cleaning the bevel portion W1 of the wafer W in the substrate cleaning apparatuses 1A and 1B configured as described above will be described based on the flow of FIG.
First, the spin chuck 2 is driven upward by the drive unit 3 with respect to the wafer W carried into the substrate cleaning apparatuses 1A and 1B, and the wafer W is held on the spin chuck 2 by the negative pressure generated by the decompression device 4 (FIG. 6 step S1).

Next, the spin chuck 2 is rotationally driven around the vertical axis by the drive unit 3, and the wafer W rotates at a predetermined rotational speed (for example, 400 rpm) (step S2 in FIG. 6).
Next, a predetermined amount of cleaning liquid is discharged onto the surface of the rotating wafer W by the surface cleaning unit 12 for a predetermined time (for example, 60 seconds) (step S3 in FIG. 6). Thereby, the surface of the wafer W1 and the bevel portion W1 become wet with the cleaning liquid, and in the subsequent cleaning of the bevel portion W1, scattering of foreign matters to the wafer surface due to the cleaning pressure is suppressed.

  After the surface cleaning unit 12 stops discharging the cleaning liquid onto the wafer W, the cleaning liquid spraying unit 7 applies a cleaning liquid in a vapor state (for example, 80 ° C. to 250 ° C.) to the bevel portion W1 of the rotating wafer W at a predetermined pressure (0 .4 MPa) for a predetermined time (for example, 60 sec). In this process, since the cleaning liquid is in a vapor state, it effectively penetrates into the resist film formed on the bevel portion W1 and the resist film is easily peeled off. The cleaning liquid is directly applied to the bevel portion at a predetermined pressure. Since it hits W1, the resist solution is easily peeled off (step S4 in FIG. 6).

  When the cleaning liquid injection to the bevel W1 by the cleaning liquid injection unit 7 is completed, a predetermined amount of cleaning liquid is again discharged onto the surface of the rotating wafer W by the surface cleaning unit 12 for a predetermined time (step S5 in FIG. 6). As a result, the cleaning liquid or foreign matter adhering to the wafer surface at the time of cleaning the bevel in the previous step S4 is washed away into the cup member 5.

  After the surface cleaning unit 12 stops discharging the cleaning liquid onto the wafer surface, the wafer W is rotated at a predetermined rotation speed (for example, 2000 rpm) for a predetermined time (for example, 15 seconds), subjected to a shake-off drying process, and the bevel part cleaning process is performed. The process ends (step S6 in FIG. 6).

As described above, according to the embodiment of the substrate cleaning apparatus and the substrate cleaning method of the present invention, since the cleaning liquid can be directly applied to the bevel portion W1 of the rotating wafer, the bevel portion W1 can be effectively applied. The resist film and foreign matter can be removed.
In particular, since the cleaning liquid is in a vapor state, it effectively penetrates into the resist film formed on the bevel portion W1 and the resist film is easily peeled off. The cleaning liquid directly hits the bevel portion W1 at a predetermined pressure. Therefore, the resist film can be easily peeled off.
Therefore, in the subsequent substrate processing, contamination due to the foreign matter attached to the bevel portion W1 can be prevented, and a decrease in yield can be suppressed.

In the above-described embodiment, the vaporized pure water is described as an example of the cleaning liquid sprayed to the bevel portion W1, but the present invention is not limited to this.
For example, the cleaning liquid may be a vapor containing a chemical liquid. The vapor containing the chemical liquid may be a vapor of the chemical liquid itself (chemical liquid vapor), or may be a mixture of the chemical liquid vapor in a carrier gas such as an inert gas. As the chemical solution, a chemical solution containing an acid such as hydrofluoric acid, nitric acid, acetic acid, hydrochloric acid, or sulfuric acid, or a chemical solution containing an alkali such as ammonia can be employed. Moreover, the said chemical | medical solution may be the liquid mixture which added organic solvents, such as oxidizing agents, such as hydrogen peroxide water and ozone, or methanol, to these acids or alkalis.

Alternatively, the cleaning liquid may be a vapor containing a chemical gas. The vapor containing chemical gas may be a mixture of chemical gas and water vapor, or may be a mixture of chemical gas and vapor of organic solvent such as methanol. It may be mixed in a carrier such as an active gas. In addition, as the chemical gas, for example, a gas containing any one of anhydrous hydrofluoric acid gas, ammonia gas, hydrogen chloride gas, nitrogen dioxide gas, and SO ₃ gas, or two or more of these gases The mixed gas can be employed.
In addition, the cleaning liquid ejected from the nozzle 11 of the cleaning liquid ejecting unit 7 is in a vapor state, but is not limited to the vapor state, and may be in an aerosol form.

  In the present invention, the substrate that can be cleaned is not limited to a semiconductor wafer, and an LCD substrate, a glass substrate, a photomask, a printed substrate, and the like are also possible.

  The present invention can be applied to a substrate cleaning apparatus for cleaning a substrate end portion (bevel portion) of a semiconductor wafer or the like, and can be suitably used in the semiconductor manufacturing industry, the electronic device manufacturing industry, and the like.

FIG. 1 is a schematic configuration diagram of a coating and developing apparatus provided with a substrate cleaning apparatus according to the present invention. FIG. 2 is a schematic configuration diagram of a substrate cleaning apparatus according to the present invention. FIG. 3 is a plan view for explaining an arrangement example of the nozzles of the cleaning liquid ejecting unit. FIG. 4 is a plan view for explaining another arrangement example of the nozzles of the cleaning liquid ejecting unit. FIG. 5 is a diagram showing another form of the cleaning liquid ejecting unit. FIG. 6 is a flowchart showing an operation process of the substrate cleaning apparatus of FIG.

Explanation of symbols

1A, 1B Substrate cleaning device 2 Spin chuck (substrate holding means)
3 Drive unit 4 Pressure reducing device 5 Cup member 6 Drain pipe 7 Cleaning liquid injection unit (cleaning liquid injection means)
8 Pure water supply unit 9 Pressurizing unit 10 Heater 11 Nozzle 12 Surface cleaning unit (surface cleaning means)
13 Nozzle 14 Cleaning liquid supply unit 20 Cassette station 30 Processing station 40 Interface unit 50 Immersion exposure apparatus W Semiconductor wafer (substrate)

Claims (2)

A substrate cleaning apparatus for cleaning a bevel portion of a substrate,
A substrate holding means for holding the substrate in a substantially horizontal posture, and rotating the substrate about a vertical axis;
Cleaning liquid ejecting means for ejecting the cleaning liquid laterally and tangentially to the bevel portion of the substrate held by the substrate holding means and rotating at a predetermined rotational speed , and in the direction opposite to the rotation direction of the substrate ;
A suction means provided around the cleaning liquid ejecting means, for sucking from a side and a tangential direction with respect to the bevel portion of the substrate and from a direction opposite to the rotation direction of the substrate ;
The cleaning liquid spraying unit sprays a vapor or aerosol cleaning liquid from the side to the bevel portion of the substrate,
The substrate cleaning apparatus, wherein the suction means sucks an atmosphere in the vicinity of the tip of the cleaning liquid ejecting means. 2. The substrate cleaning apparatus according to claim 1 , further comprising surface cleaning means for supplying a cleaning liquid to the surface of the substrate held by the substrate holding means and rotating at a predetermined rotation speed.

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