JP6368145B2 - Substrate cleaning method and substrate cleaning apparatus - Google Patents

Description

  The present invention relates to a substrate cleaning method and a substrate cleaning apparatus.

  In cleaning systems for silicon wafers, photomasks, glass disks, III-V semiconductors, etc., a cleaning tool that applies external stress to release solid foreign matter and organic substances adhering to the surface of the object to be cleaned Is often used.

  As a typical cleaning tool, an ultrasonic cleaner (for example, refer to Patent Document 1) that radiates ultrasonic waves into a liquid, a one-fluid nozzle that jets liquid onto a substrate at high speed, and a two-fluid nozzle that mixes gas and liquid (See, for example, Patent Document 2).

Further, brush cleaning using a brush using resinous fibers is often used.
In addition, cleaning is also used in which fine particles such as carbon dioxide gas, ice, and argon solidified by cooling are sprayed onto the substrate (see, for example, Patent Document 3).

JP 2011-165911 A JP 2012-212032 A JP 2006-140201 A

  However, since the ultrasonic cleaning, nozzle cleaning, and brush cleaning described above have a characteristic of cleaning by applying external stress to the foreign matter on the substrate, external stress is applied to the substrate itself along with removal of the foreign matter. There has been a problem that the substrate surface material and the internal material may be damaged or broken.

  In addition, since the cleaning method used in the current semiconductor manufacturing process uses a large amount of cleaning liquid and cleaning gas, the chemical processing cost and environmental burden are increasing, and a cleaning method that considers reducing the amount of chemical used is proposed. Was necessary.

  The present invention has been made in view of the above problems, and can remove foreign substances without applying external stress to the substrate itself, and can reduce the amount of cleaning liquid and cleaning gas used. It is an object of the present invention to provide a substrate cleaning method and a substrate cleaning apparatus.

  In order to achieve the above object, the present invention provides a method for cleaning a substrate using a cleaning liquid, the step of introducing the substrate into a chamber, the step of reducing the pressure in the chamber, and the cleaning liquid in the chamber. There is provided a method for cleaning a substrate, comprising a step of supplying the substrate and a step of freezing a cleaning liquid adhering to the surface of the substrate.

  In this way, by freezing the cleaning liquid adhering to the substrate surface, the cleaning liquid expands and a stress acts on the substrate upward, and the foreign substance on the substrate surface can be released by the stress. The foreign matter can be removed with little stress applied, and the amount of cleaning liquid or cleaning gas used can be reduced.

At this time, it is preferable to further include a step of cooling the inside of the chamber to 0 ° C. or lower before the step of introducing the substrate.
In this way, if the inside of the chamber is cooled to 0 ° C. or lower in advance, the cleaning liquid is cooled in the chamber before reaching the substrate, thereby shortening the time until the cleaning liquid attached to the substrate surface is frozen. be able to.

At this time, it is preferable to freeze the cleaning liquid adhering to the substrate surface by cooling the substrate.
With such a configuration, the cleaning liquid adhering to the substrate surface can be efficiently frozen.

At this time, it is preferable that the substrate is cooled by a support that supports the substrate and has a Peltier element that can be temperature-controlled by current control.
With such a configuration, the cleaning liquid adhering to the substrate surface can be suitably frozen.

At this time, after the step of freezing the cleaning liquid, the substrate may be further heated by thawing the frozen cleaning liquid and drying the substrate.
With such a configuration, the cleaned substrate can be transported out of the chamber.

At this time, it is preferable that the substrate is heated by a support tool that supports the substrate and has a Peltier element that can be temperature-controlled by current control.
With such a configuration, the frozen cleaning liquid on the substrate surface can be thawed efficiently.

At this time, it is preferable to repeat the freezing of the cleaning liquid adhering to the substrate and the thawing of the frozen cleaning liquid a plurality of times.
With such a configuration, foreign substances on the substrate surface can be more effectively separated.

At this time, the cleaning liquid includes ultrapure water, inorganic acid, inorganic alkali, organic acid, organic alkali, and ozone water to which at least one of O ₃ gas, NH ₃ gas, F ₂ gas, and Ar gas is excessively added. Gas dissolved water, electrolyzed water, those obtained by adding a surfactant to these, or those obtained by mixing two or more of these are preferable.
By using such a cleaning liquid, organic substances on the surface of the substrate can be efficiently decomposed.

At this time, it is preferable to add at least one of O ₃ gas, NH ₃ gas, F ₂ gas, Ar gas, CO ₂ gas, He gas, and N ₂ gas to the atmosphere when the cleaning liquid is frozen.
With such a configuration, decomposition of organic substances on the substrate surface and cooling of the cleaning liquid attached to the substrate surface can be promoted.

At this time, in the step of supplying the cleaning liquid into the chamber, the cleaning liquid is preferably supplied into the chamber in a mist form.
With such a configuration, the cleaning liquid before reaching the substrate can be efficiently cooled.

At this time, in the step of supplying the cleaning liquid into the chamber, it is preferable that the mist-like cleaning liquid is sucked from an exhaust suction port provided in a downward direction of the substrate in the chamber.
With such a configuration, the mist-like cleaning liquid can be supplied to the substrate more uniformly.

At this time, it is preferable to cool or heat the inside of the chamber by a Peltier element that is temperature-controllable by current control provided on the wall surface of the chamber.
With such a configuration, the inside of the chamber can be efficiently cooled or heated.

At this time, as the substrate, any one of a photomask, a glass disk, a Si wafer, a Ge wafer, a GaAs wafer, and a SiC wafer, or a substrate used in a manufacturing process of a flat panel or a multilayer ceramic is used. it can.
As the substrate to which the cleaning method of the present invention is applied, those described above can be suitably used.

  The present invention is also a substrate cleaning apparatus that uses a cleaning liquid, and is connected to the chamber, a cleaning liquid line that supplies the cleaning liquid into the chamber, and the chamber and an exhaust line, and depressurizes the inside of the chamber. A vacuum pump; a support provided in the chamber for supporting the substrate; and a cooling mechanism for cooling the substrate; and the cleaning liquid is supplied to the cleaning liquid line in a state where the pressure in the chamber is reduced by the vacuum pump. A substrate cleaning apparatus, wherein the substrate is supplied to the substrate supported by the support in the chamber, and the cleaning liquid attached to the substrate is frozen by the cooling mechanism to clean the substrate. provide.

  With such a configuration, freezing the cleaning liquid attached to the substrate surface expands the cleaning liquid, and stress acts on the substrate in the upward direction. A foreign substance can be removed with almost no external stress applied, and a cleaning apparatus that can reduce the amount of cleaning liquid and cleaning gas used can be provided.

At this time, it is preferable that the cooling mechanism is a first Peltier element that is temperature-controllable by current control provided on the support.
With such a configuration, the cleaning liquid adhering to the substrate surface can be efficiently frozen.

At this time, it is preferable to further include a second Peltier element provided on the wall surface of the chamber and capable of temperature control by current control.
With such a configuration, the inside of the chamber can be efficiently cooled or heated.

At this time, it is preferable to further have a heating mechanism for heating the substrate.
With such a configuration, the frozen cleaning liquid can be thawed efficiently.

At this time, it is preferable that the first Peltier element and the second Peltier element are used as the heating mechanism.
As described above, the first Peltier element provided on the support and the second Peltier element provided on the wall surface of the chamber can be suitably used as the substrate heating mechanism.

At this time, it is preferable that the cleaning liquid line has a function of supplying the cleaning liquid into the chamber in a mist form.
With such a configuration, the cleaning liquid before reaching the substrate can be efficiently cooled.

At this time, it is preferable that an exhaust suction port of the exhaust line is provided below the substrate in the chamber to suck the mist-like cleaning liquid from the exhaust suction port.
With such a configuration, the mist-like cleaning liquid can be supplied to the substrate more uniformly.

At this time, the cleaning liquid includes ultrapure water, inorganic acid, inorganic alkali, organic acid, organic alkali, and ozone water to which at least one of O ₃ gas, NH ₃ gas, F ₂ gas, and Ar gas is excessively added. Gas dissolved water, electrolyzed water, those obtained by adding a surfactant to these, or those obtained by mixing two or more of these are preferable.
By using the cleaning liquid as described above, organic substances on the substrate surface can be efficiently decomposed.

At this time, the chamber further includes a gas line for supplying a gas, and the gas supplied by the gas line includes an O ₃ gas, an NH ₃ gas, an F ₂ gas, an Ar gas, a CO ₂ gas, a He gas, It is preferably at least one of N ₂ gas.
With this configuration, at least one of O ₃ gas, NH ₃ gas, F ₂ gas, Ar gas, CO ₂ gas, He gas, and N ₂ gas can be added to the atmosphere when the cleaning liquid is frozen. Decomposition of organic substances on the substrate surface and cooling of the cleaning liquid adhering to the substrate surface can be promoted.

At this time, the substrate may be a photomask, a glass disk, a Si wafer, a Ge wafer, a GaAs wafer, a SiC wafer, or a substrate used in a manufacturing process of a flat panel or a multilayer ceramic. preferable.
As the substrate to be cleaned by the cleaning apparatus of the present invention, the above can be suitably used.

As described above, according to the substrate cleaning method of the present invention, by freezing the cleaning liquid adhering to the substrate surface, the cleaning liquid expands and a stress acts on the substrate, and the stress causes foreign matter on the substrate surface. Can be removed, foreign matter can be removed with almost no external stress applied to the substrate itself, and the amount of cleaning liquid or cleaning gas used can be reduced.
In addition, according to the substrate cleaning apparatus of the present invention, the cleaning liquid that adheres to the substrate surface is frozen, so that the cleaning liquid expands and a stress acts on the substrate, and the foreign substance on the substrate surface is released by the stress. In addition, a foreign substance can be removed with little external stress applied to the substrate itself, and a cleaning apparatus that can reduce the amount of cleaning liquid or cleaning gas used can be provided.

It is a flowchart which shows an example of the embodiment of the washing | cleaning method of the board | substrate of this invention. It is a figure which shows the molecular model of a washing | cleaning liquid. It is a figure which shows the molecular model of the washing | cleaning liquid at the time of freezing. It is a figure which shows the molecular model at the time of freezing of the ozone water which ozone melt | dissolved excessively. It is sectional drawing which shows an example of the embodiment of the washing | cleaning apparatus of the board | substrate of this invention. It is a graph which shows the repetition frequency dependence of the particle | grain (foreign material) removal rate of 0.1 micrometer or more in an Example, the comparative example 1-1, the comparative example 1-2, and the comparative example 3. FIG. 5 is a graph showing a removal rate of particles (foreign matter) of 0.1 μm or more after 3 cycles in Examples, Comparative Example 1-1, Comparative Example 1-2, and Comparative Example 3.

Hereinafter, the present invention will be described in detail as an example of an embodiment with reference to the drawings, but the present invention is not limited thereto.
As described above, as a typical cleaning tool, an ultrasonic cleaner that emits ultrasonic waves into a liquid, a one-fluid nozzle that jets liquid onto a substrate at high speed, and a two-fluid nozzle that mixes gas and liquid are known. In many cases, brush cleaning using a brush using resinous fibers is also used. However, ultrasonic cleaning, nozzle cleaning, and brush cleaning are performed by applying external stress to foreign matter on the substrate. Therefore, there is a problem that external stress is applied to the substrate itself along with the removal of foreign matters, and the substrate surface material and internal material may be damaged or broken.
In addition, since the cleaning method used in the current semiconductor manufacturing process uses a large amount of cleaning liquid and cleaning gas, the chemical processing cost and environmental burden are increasing, and a cleaning method that considers reducing the amount of chemical used is proposed. Was necessary.

Accordingly, the inventors have made extensive studies on a method for cleaning a substrate that can remove foreign matter without applying external stress to the substrate itself and can reduce the amount of cleaning liquid and cleaning gas used. .
As a result, by freezing the cleaning liquid adhering to the substrate surface, the cleaning liquid expands and a stress acts on the substrate upward, and the foreign substance on the substrate surface can be detached by the stress. It has been found that foreign substances can be removed with little stress applied, and that the amount of cleaning liquid and cleaning gas used can be reduced, leading to the present invention.
That is, as shown in FIG. 2, the pure water used as the cleaning liquid is intermolecularly connected by hydrogen bonds bonded between the element oxygen element and the hydrogen element, and the hydrogen bond is an interatomic distance between oxygen and hydrogen. Is formed at 0.176 nm and 0.096 nm, and exists in a molecular state with a high degree of freedom, but the cooled pure water becomes solid ice as shown in FIG. And hydrogen form crystals by forming two covalent bonds and two hydrogen bonds in the tetrahedral direction.
As described above, the liquid state has a degree of freedom. However, it has a structure with many gaps (the filling ratio of water molecules is 32%) in which the crystal orientation is prioritized with crystallization, and the volume increases. It has been.
Accordingly, due to the solidification of the liquid, the liquid on the substrate surface is subjected to an upward stress due to the expansion phenomenon, and the surface foreign matter is detached by the stress (see FIG. 3).

Hereinafter, an example of an embodiment of the substrate cleaning apparatus of the present invention will be described with reference to FIG.
As shown in FIG. 5, the cleaning apparatus 10 is connected via a chamber 11, a cleaning liquid line 17 that supplies cleaning liquids 19 and 20 into the chamber 11, and the chamber 11 and an exhaust line 23, and depressurizes the inside of the chamber 11. A vacuum pump 26, a support (plate) 12 provided in the chamber 11 for supporting the substrate 14 to be cleaned, and a cooling mechanism for cooling the substrate 14 are provided. In this state, the cleaning liquid is supplied to the substrate 14 supported by the support 12 in the chamber 11 through the cleaning liquid line 17 and the substrate 14 is cleaned by freezing the cleaning liquid 20 attached to the substrate 14 by the cooling mechanism. .
An exhaust valve 24 can be provided between the exhaust line 23 and the vacuum pump 26.
Further, the wall surface of the chamber 11 is preferably made of SUS404 (thermal conductivity: 27.2 W / m · K) or aluminum material (thermal conductivity: approximately 200 W / m · K) having high thermal conductivity.
Further, the substrate fixing pin 15 may be provided on the support (plate) 12.

  With this configuration, freezing the cleaning liquid attached to the substrate surface expands the cleaning liquid, and stress acts on the substrate in the upward direction. A foreign substance can be removed without applying external stress, and a cleaning apparatus that can reduce the amount of cleaning liquid or cleaning gas used can be provided.

The cooling mechanism may be, for example, the first Peltier element 13 that can be temperature-controlled by current control provided on the support 12.
By adopting such a cooling mechanism for cooling the substrate 14, the cleaning liquid 20 adhering to the surface of the substrate 14 can be efficiently frozen.

The cleaning apparatus 10 can further include a second Peltier element 16 that is provided on the wall surface of the chamber 11 and can be temperature-controlled by current control.
With such a configuration, the inside of the chamber can be efficiently cooled or heated.

The cleaning apparatus 10 can further include a heating mechanism that heats the substrate 14.
With such a configuration, the frozen cleaning solution can be thawed.

As the heating mechanism, it is preferable to use the first Peltier element 13 and the second Peltier element 16.
Thus, as the heating mechanism for the substrate 14, the first Peltier element 13 provided on the support 12 and the second Peltier element 16 provided on the wall surface of the chamber 11 can be suitably used.

It is preferable that the cleaning liquid line 17 has a function of supplying the cleaning liquid 19 into the chamber 11 in a mist form.
With such a configuration, the cleaning liquid 19 before reaching the substrate 14 can be efficiently cooled.

The exhaust suction port 25 of the exhaust line 23 is preferably provided below the substrate 14 in the chamber 11 and sucks the mist-like cleaning liquid 19 from the exhaust suction port 25.
With such a configuration, the mist-like cleaning liquid 19 can be supplied to the substrate 14 more uniformly.

The cleaning liquids 19 and 20 are not particularly limited, but ultrapure water, inorganic acid, inorganic alkali, organic acid, organic alkali, ozone, to which at least one of O ₃ gas, NH ₃ gas, F ₂ gas, and Ar gas is excessively added. It is preferably any of water-containing gas-dissolved water, electrolyzed water, those obtained by adding a surfactant to these, or those obtained by mixing two or more of these.
By using the cleaning liquid as described above, the organic substances on the surface of the substrate 11 can be efficiently decomposed.

The cleaning apparatus 10 further includes a gas line 18 for supplying gas to the chamber 11, and the gas supplied by the gas line 18 is not particularly limited, but is O ₃ gas, NH ₃ gas, F ₂ gas, Ar gas, CO 2 It is preferably at least one of ₂ gas, He gas, and N ₂ gas.
With this configuration, at least one of O ₃ gas, NH ₃ gas, F ₂ gas, Ar gas, CO ₂ gas, He gas, and N ₂ gas can be added to the atmosphere when the cleaning liquid is frozen. Decomposition of organic substances on the substrate surface and cooling of the cleaning liquid adhering to the substrate surface can be promoted.

Although it does not specifically limit as the board | substrate 14, It is set as the board | substrate used for the manufacturing process of either a photomask, a glass disk, Si wafer, Ge wafer, GaAs wafer, SiC wafer or any of a flat panel and a multilayer ceramic. be able to.
As the substrate 14 to be cleaned by the cleaning apparatus 10, the above can be suitably used.

The cleaning device 10 preferably has a chamber temperature detector 21 that detects the temperature of the chamber 11.
With such a configuration, the temperature of the chamber 11 can be managed with high accuracy.

Further, the cleaning device 10 preferably has a transfer shutter 22.
With such a configuration, the substrate 14 can be easily carried out / in by opening and closing the conveyance shutter 22.

Next, an example of an embodiment of the substrate cleaning method of the present invention will be described with reference to FIGS.
The substrate cleaning method of the present invention can be performed using the cleaning apparatus 10 of FIG.
First, a substrate 14 that is an object to be cleaned is introduced into the chamber 11 (see step S11 in FIG. 1).
For example, the transfer shutter 22 is opened, and the substrate 14 transferred by the robot is placed on the plate (support) 12.
After the conveyance, the conveyance shutter 22 is closed.

Next, the pressure inside the chamber 11 is reduced (see step S12 in FIG. 1).
For example, the exhaust valve 24 is opened, and the inside of the chamber 11 is depressurized by the vacuum pump 26 connected to the chamber 11 through the exhaust line 23.

Next, the cleaning liquid is supplied to the substrate 14 in the chamber 11 (see step S13 in FIG. 1).
For example, the cleaning liquid is supplied to the substrate 14 in the chamber 11 by the cleaning liquid line 17 provided in the chamber 11.

Next, the cleaning liquid 20 attached to the substrate 14 is frozen (see step S14 in FIG. 1).
For example, the cleaning liquid 20 attached to the substrate 14 can be frozen by cooling the substrate 14.

  In this way, by freezing the cleaning liquid adhering to the substrate surface, the cleaning liquid expands, and a stress acts on the substrate in the upward direction. Foreign matter can be removed with almost no external stress applied. In addition, the amount of cleaning liquid or cleaning gas used can be reduced as compared with the case of dipping or pouring.

Note that it is preferable to further include a step of cooling the chamber 11 to 0 ° C. or lower before the step of introducing the substrate 14.
For example, upon receiving a signal of 0 ° C. or less output from the chamber temperature detector 21, the transfer shutter 22 may be opened, and the substrate 14 transferred by the robot may be placed on the plate (support) 12.
In this way, if the inside of the chamber is cooled to 0 ° C. or lower in advance, the cleaning liquid is cooled in the chamber before reaching the substrate, thereby shortening the time until the cleaning liquid attached to the substrate surface is frozen. be able to.

Moreover, it is preferable to cool the said board | substrate with the support tool which supports the board | substrate 14 and has the Peltier element 13 which can control temperature by electric current control.
With such a configuration, the cleaning liquid 20 attached to the surface of the substrate 11 can be suitably frozen.

In addition, after the step of freezing the cleaning liquid, the substrate 14 may be heated to further defrost the frozen cleaning liquid 20 and the substrate 14 may be dried.
With such a configuration, the cleaned substrate can be quickly transported out of the chamber.

At this time, it is preferable to heat the substrate with the support 12 having the Peltier element 13 that supports the substrate 14 and can be temperature-controlled by current control.
With such a configuration, the frozen cleaning liquid 20 on the surface of the substrate 14 can be thawed efficiently.

Further, it is preferable to repeat the freezing of the cleaning liquid 20 attached to the substrate 14 and the thawing of the frozen cleaning liquid 20 a plurality of times.
With such a configuration, foreign substances on the surface of the substrate 14 can be more effectively separated.

The cleaning liquids 19 and 20 are made of ultrapure water, inorganic acid, inorganic alkali, organic acid, organic alkali, or ozone water to which at least one of O ₃ gas, NH ₃ gas, F ₂ gas, and Ar gas is excessively added. It is preferable that it is either the dissolved gas containing water, electrolyzed water, what added these to these, or what mixed these 2 or more types.
By using such a cleaning liquid, organic substances on the surface of the substrate can be efficiently decomposed.
For example, as shown in FIG. 4, by cooling ultrapure water (O ₃ gas concentration: approximately 100 ppm) in which O ₃ gas is excessively dissolved, ozone gas is filled in the crystal structure empty package simultaneously with crystallization. The
Accordingly, simultaneously with the removal of the foreign matter by the expansion action, it becomes possible to promote the oxidative decomposition of the ozone gas sealed in the ice into the organic substance existing on the substrate surface. That is, in the conventional SC1 cleaning (cleaning using a mixed solution of hydrogen peroxide and ammonia), the physical separation action and the organic substance decomposition action are simultaneously performed. In the present invention, the organic substance is dissolved in the ice. The same effect can also be shown by filling a strong gas.

Further, it is preferable to add at least one of O ₃ gas, NH ₃ gas, F ₂ gas, Ar gas, CO ₂ gas, He gas, and N ₂ gas to the atmosphere when the cleaning liquid 20 is frozen.
With such a configuration, decomposition of organic substances on the surface of the substrate 14 and cooling of the cleaning liquid 20 attached to the surface of the substrate 14 can be promoted.

In the step of supplying the cleaning liquid 19 into the chamber 11, it is preferable to supply the cleaning liquid 19 into the chamber in a mist form.
With such a configuration, the cleaning liquid 19 before reaching the substrate can be efficiently cooled.

In the step of supplying the cleaning liquid into the chamber, it is preferable that the mist-like cleaning liquid is sucked from an exhaust suction port provided in a downward direction of the substrate in the chamber.
With such a configuration, the mist-like cleaning liquid can be supplied to the substrate more uniformly.

Moreover, it is preferable to cool or heat the inside of the chamber by a Peltier element that is temperature-controllable by current control provided on the wall surface of the chamber.
With such a configuration, the inside of the chamber can be efficiently cooled or heated.

Further, as the substrate 14, any of a photomask, a glass disk, a Si wafer, a Ge wafer, a GaAs wafer, and a SiC wafer, or a substrate used in a manufacturing process of a flat panel or a multilayer ceramic can be used. .
As the substrate to which the cleaning method of the present invention is applied, those described above can be suitably used.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these.

(Example)
A prescribed particle was applied to a wafer having a diameter of 200 mm to produce a contaminated wafer.
A wafer prepared on 300 mm square dry ice was placed in an FFU (Fan Filter Unit: a unit in which a fan and a filter were incorporated in a housing) environment, and the wafer was cooled.
Thereafter, about 50 mL of ultrapure water was supplied as a cleaning liquid onto the wafer and left for 15 minutes until the cleaning liquid was frozen.
After the cleaning solution was frozen, the wafer was removed from the dry ice, and the wafer was placed on a spin table and left for 15 minutes to allow the cleaning solution to thaw naturally.
After thawing, rinsing and spin drying were performed.
The washing process was repeated for 3 cycles.

Number of wafer particles before the cleaning process, number of wafer particles (foreign matter) after the cleaning process in the first cycle, number of wafer particles after the cleaning process in the second cycle, and after the cleaning process in the third cycle The number of particles on the wafer was measured, and the particle removal rate after the above-described cleaning treatment in the first to third cycles was determined. The result is shown in FIG.
FIG. 7 shows the particle removal rate after the above-described cleaning treatment in the third cycle.
Table 1 shows the amount of liquid and the amount of gas used per wafer in the examples.

(Comparative Example 1)
Using a conventional cleaning tool, the amount of liquid used and the amount of gas used per wafer of an ultrasonic nozzle type (a type in which a cleaning liquid on which ultrasonic waves were placed were sprayed) were examined. The results are shown in Table 1.
In the same manner as in the example, prescribed particles were applied to a wafer having a diameter of 200 mm to produce a contaminated wafer.
The application conditions of ultrasonic waves in the ultrasonic nozzle type were set to the following two levels, and the cleaning treatment was repeated three cycles for each.
Level 1 ... 1.5 MHz, 100 W (Comparative Example 1-1)
Level 2 ... 3.0 MHz, 48 W (Comparative Example 1-2)
The number of wafer particles before the cleaning process, the number of wafer particles after the cleaning process in Comparative Example 1-1 and Comparative Example 1-2 in the first cycle, and the Comparative Example 1-1 and Comparative Example 1-2 in the second cycle The number of wafer particles after the cleaning process and the number of wafer particles after the cleaning process of Comparative Example 1-1 and Comparative Example 1-2 in the third cycle were measured, and Comparative Example 1-1 in the first to third cycles. And the particle removal rate after the washing process of Comparative Example 1-2 was determined. The result is shown in FIG.
Moreover, the particle removal rate after the cleaning process of Comparative Example 1-1 and Comparative Example 1-2 in the third cycle is shown in FIG.

(Comparative Example 2)
Using a conventional cleaning tool, the amount of liquid used and the amount of gas used per wafer of an ultrasonic Dip type (type immersed in a cleaning liquid to which ultrasonic waves were applied) were examined. The results are shown in Table 1.

(Comparative Example 3)
Using a conventional cleaning tool, the amount of liquid and the amount of gas used per wafer of a two-fluid nozzle type (type in which pure water and nitrogen gas are injected from the nozzle) were examined. The results are shown in Table 1.
In the same manner as in the example, prescribed particles were applied to a wafer having a diameter of 200 mm to produce a contaminated wafer.
The cleaning process using a two-fluid nozzle type cleaning tool was repeated three cycles.
The number of wafer particles before the cleaning process, the number of wafer particles after the first cleaning process, the number of wafer particles after the second cleaning process, and the number of wafer particles after the third cleaning process. The particle removal rate after the cleaning treatment of the first to third cycles was measured. The result is shown in FIG.
Moreover, the particle removal rate after the cleaning process of the 3rd cycle is shown in FIG.

  As can be seen from Table 1, in the examples, the amount of cleaning liquid used is small compared to Comparative Example 1-2, which is a conventional cleaning tool, and compared with Comparative Example 3, which is a conventional cleaning tool. Since the amount of gas used is small, the environmental load can be reduced.

  As can be seen from FIGS. 6-7, when attention is paid to the particle (foreign matter) removal rate after 3 cycles, in the example, Comparative Example 1-1, Comparative Example 1-2, and Comparative Example, which are conventional cleaning tools, are used. Compared with 3, a particle (foreign matter) removal rate equal to or higher than that is obtained.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

10 ... Cleaning device, 11 ... Chamber, 12 ... Plate (support),
13 ... Peltier element (first Peltier element), 14 ... Substrate, 15 ... Substrate fixing pin,
16 ... Peltier element (second Peltier element), 17 ... Cleaning liquid line,
18 ... gas line, 19 ... cleaning solution, 20 ... cleaning solution adhering to the substrate surface,
21 ... Chamber temperature detector, 22 ... Transfer shutter, 23 ... Exhaust line,
24 ... Exhaust valve, 25 ... Exhaust suction port, 26 ... Vacuum pump.

Claims (24)

A method for cleaning a substrate using a cleaning liquid,
Introducing the substrate into a chamber;
Reducing the pressure in the chamber;
Supplying the cleaning liquid to the substrate in the chamber;
And a step of freezing the cleaning liquid adhering to the surface of the substrate.   The substrate cleaning method according to claim 1, further comprising a step of cooling the chamber to 0 ° C. or lower before the step of introducing the substrate.   The substrate cleaning method according to claim 1 or 2, wherein the cleaning liquid adhering to the substrate surface is frozen by cooling the substrate.   The substrate cleaning method according to claim 3, wherein the substrate is cooled by a support that supports the substrate and includes a Peltier element that can be temperature-controlled by current control. After the step of freezing the washing liquid,
Thawing the frozen cleaning solution by heating the substrate;
The substrate cleaning method according to claim 1, further comprising a step of drying the substrate.   6. The method of cleaning a substrate according to claim 5, wherein the substrate is heated by a support that supports the substrate and has a Peltier element that can be temperature-controlled by current control.   The method for cleaning a substrate according to claim 5 or 6, wherein freezing of the cleaning liquid adhering to the substrate and thawing of the frozen cleaning liquid are repeated a plurality of times. The cleaning liquid is gas-dissolved water containing ultrapure water, inorganic acid, inorganic alkali, organic acid, organic alkali, and ozone water to which at least one of O ₃ gas, NH ₃ gas, F ₂ gas, and Ar gas is excessively added. The substrate according to any one of claims 1 to 7, wherein the substrate is one of electrolyzed water, electrolyzed water, a surfactant added thereto, or a mixture of two or more thereof. Cleaning method. _{2. At} least one of O ₃ gas, NH ₃ gas, F ₂ gas, Ar gas, CO ₂ gas, He gas, and N ₂ gas is added to the atmosphere when freezing the cleaning liquid. The method for cleaning a substrate according to claim 8.   10. The substrate cleaning method according to claim 1, wherein in the step of supplying the cleaning liquid into the chamber, the cleaning liquid is supplied in the chamber in a mist form. 11.   The method of claim 10, wherein in the step of supplying the cleaning liquid into the chamber, the mist-shaped cleaning liquid is sucked from an exhaust suction port provided in a downward direction of the substrate in the chamber. Substrate cleaning method.   12. The substrate cleaning according to claim 1, wherein the inside of the chamber is cooled or heated by a Peltier element that is temperature-controllable by current control provided on a wall surface of the chamber. Method.   As the substrate, any one of a photomask, a glass disk, a Si wafer, a Ge wafer, a GaAs wafer, and a SiC wafer, or a substrate used in a manufacturing process of a flat panel or a multilayer ceramic is used. The method for cleaning a substrate according to any one of claims 1 to 12. A substrate cleaning apparatus using a cleaning liquid,
A chamber;
A cleaning liquid line for supplying the cleaning liquid into the chamber;
A vacuum pump connected to the chamber via an exhaust line and depressurizing the chamber;
A support provided in the chamber and supporting the substrate;
A cooling mechanism for cooling the substrate,
The cleaning liquid is supplied to the substrate supported by the support in the chamber through the cleaning liquid line in a state where the pressure in the chamber is reduced by the vacuum pump, and the cleaning liquid attached to the substrate is frozen by the cooling mechanism. A substrate cleaning apparatus for cleaning the substrate.   15. The substrate cleaning apparatus according to claim 14, wherein the cooling mechanism is a first Peltier element that is temperature-controllable by current control provided in the support.   16. The substrate cleaning apparatus according to claim 14, further comprising a second Peltier element provided on a wall surface of the chamber and capable of temperature control by current control.   The substrate cleaning apparatus according to any one of claims 14 to 16, further comprising a heating mechanism for heating the substrate. Examples heating mechanism, a substrate washing apparatus according to claim 17, characterized in that using a Peltier element.   19. The substrate cleaning apparatus according to claim 14, wherein the cleaning liquid line has a function of supplying the cleaning liquid into the chamber in a mist form.   The exhaust suction port of the exhaust line is provided below the substrate in the chamber, and sucks the mist-like cleaning liquid from the exhaust suction port. Substrate cleaning equipment. The cleaning liquid is gas-dissolved water containing ultrapure water, inorganic acid, inorganic alkali, organic acid, organic alkali, and ozone water to which at least one of O ₃ gas, NH ₃ gas, F ₂ gas, and Ar gas is excessively added. 21. The substrate according to any one of claims 14 to 20, wherein the substrate is one of electrolyzed water, electrolyzed water, a surfactant added thereto, or a mixture of two or more thereof. Cleaning device.   The apparatus for cleaning a substrate according to any one of claims 14 to 20, further comprising a gas line for supplying a gas into the chamber. The gas supplied by the gas line is at least one of O ₃ gas, NH ₃ gas, F ₂ gas, Ar gas, CO ₂ gas, He gas, and N ₂ gas. The substrate cleaning apparatus as described.   The substrate is any one of a photomask, a glass disk, a Si wafer, a Ge wafer, a GaAs wafer, and a SiC wafer, or a substrate used in a manufacturing process of a flat panel or a multilayer ceramic. The substrate cleaning apparatus according to any one of claims 14 to 23.

Images