KR102003361B1 - Method and apparatus for in-situ dry clean processing - Google Patents

Abstract

The present invention relates to a dry cleaning method for removing oxides or nitrides formed on a silicon substrate, comprising the steps of: supplying a reaction gas, which reacts with the silicon oxide or the silicon nitride, A step of producing a reaction product in which at least a part of the silicon nitride is changed to ammonium hexafluorosilicate ((NH ₄ ) ₂ SiF ₆ ) and a step of supplying a heated heat transfer gas to the silicon substrate on which the ammonium hexafluorosilicate is formed, And a reaction product removing step of removing ammonium silicate.
According to the present invention, in order to remove silicon oxide or silicon nitride formed on the substrate, a process of generating and removing ammonium hexafluorosilicate in one chamber can be performed, and productivity and hardware stability can be improved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an in-

The present invention relates to an in situ dry cleaning method and apparatus. More specifically, the present invention is directed to a process for producing and removing ammonium hexafluorosilicate in one chamber to remove silicon oxide or silicon nitride formed on a substrate, which process can improve productivity and hardware stability, To an in-situ dry cleaning method and apparatus.

As semiconductor device circuits become increasingly highly integrated and highly refined, etching and cleaning techniques that exhibit high selectivity between hetero patterns such as polysilicon, silicon oxide and nitride have been desired.

Generally, the wet etching technique has excellent particle removal characteristics, but it has a low selectivity ratio for low etching ability due to the surface tension in the high aspect ratio pattern and fine etching of the atomic level. I have a difficult problem. In addition, since the dry etching technique generates a damage layer on the wafer surface after etching due to ion bombardment incident on the wafer, there is a problem in that a subsequent process for removing the damage layer is required.

The recent years, as an alternative technique to solve this problem, the gas reaction or a radical (Radical) and hexafluoro-silicon oxide or a nitride by reacting silicic acid ammonium _{((NH 4) 2 SiF 6} ) changes into a solid layer, thus generating A dry scrubbing technique has been introduced to heat and remove the ammonium hexafluorosilicate solid layer.

However, in the case of removing the thin film having a thickness equal to or more than a certain thickness due to a low removal rate compared with other techniques, the dry cleaning technique needs to be repeatedly carried out in a reaction step of producing ammonium hexafluorosilicate and a heat treatment step of removing ammonium hexafluorosilicate, As a result, the productivity is significantly lowered compared with the conventional wet etching and dry etching.

1 is a view for explaining a conventional Ex-situ dry cleaning technique.

Referring to FIG. 1, a conventional Ex-situ dry cleaning technique is a method in which ammonium hexafluorosilicate is produced in a reaction chamber, the substrate is transferred to a heat treatment chamber and placed in a chuck heated to 120 degrees or more, According to this technology, a bottleneck phenomenon of the transfer device during repeated processes to remove oxides or nitrides of a certain thickness or more can be prevented by evaporating and removing ammonium hexafluorosilicate at a temperature using heat conduction to the substrate. There is a problem that productivity is lowered.

2 is a view for explaining a conventional in-situ dry cleaning technique.

Referring to FIG. 2, a conventional in-situ dry cleaning technique is a technique for simultaneously performing a reaction for producing ammonium hexafluorosilicate in one chamber and a heat treatment for removing ammonium hexafluorosilicate, The bottleneck problem is improved over the Ex-situ method, but since the process of bringing the chuck close to the heated showerhead for heat treatment has to be carried out, the limitation of the moving speed due to the weight of the lower module including the chuck, (UPH) and Mean Time Between Failure (MTBF), which are caused by a failure due to a failure due to a failure or the like.

Korean Patent Laid-Open Publication No. 10-2009-0071368 (Published Date: July 01, 2009, titled: substrate processing method, substrate processing apparatus and storage medium) Korean Registered Patent No. 10-0784661 (Registered Date: December 05, 2007, name: METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE)

In order to remove silicon oxide or silicon nitride formed on a substrate, the present invention can perform a process of producing and removing ammonium hexafluorosilicate in one chamber, -situ) dry cleaning method and apparatus.

Specifically, the present invention is directed to a method of manufacturing a semiconductor device, comprising: injecting a heat transfer gas heated through a showerhead onto a silicon substrate in a state where a chuck is fixed, thereby vaporizing and removing ammonium hexafluorosilicate to thereby increase the process speed, And to provide an in-tube dry cleaning method and apparatus capable of reducing deterioration and hardware instability.

According to an aspect of the present invention, there is provided a dry cleaning method for removing an oxide or nitride formed on a silicon substrate, the method comprising: supplying a reactive gas, which reacts with the silicon oxide or the silicon nitride, Oxide or silicon nitride is changed to ammonium hexafluorosilicate ((NH ₄ ) ₂ SiF ₆ ), and a step of supplying a heated heat transfer gas to the silicon substrate on which the ammonium hexafluorosilicate is formed, And a reaction product removing step of removing ammonium hexafluorosilicate.

In the dry cleaning method according to the present invention, the heat transfer gas may include at least H ₂ O.

In the dry cleaning method according to the present invention, the heating temperature of the heat transfer gas is 200-1000 ° C.

In the dry cleaning method according to the present invention, the reaction product generation step may include the steps of disposing the silicon substrate in a chuck inside the chamber, plasma processing the first reaction gas containing at least NF ₃ , And supplying the second reaction gas containing at least NH ₃ to the silicon substrate without plasma processing.

In the dry cleaning method according to the present invention, the second reaction gas is supplied in a heated state, and the heating temperature of the second reaction gas is 100-1000 ° C.

In the dry cleaning method according to the present invention, in the reaction product removing step, a gas containing N ₂ or Ar is supplied through a path independent of the heated heat transfer gas supply path supplied through the showerhead provided in the chamber Is supplied.

In the dry cleaning method according to the present invention, the temperature of the chuck is controlled at a normal temperature of -100 ° C.

In the dry cleaning method according to the present invention, the heating temperature of the showerhead is 100-200 占 폚.

In the dry cleaning method according to the present invention, the heating temperature of the inner wall surface of the chamber is 80-100 ° C.

In the dry cleaning method according to the present invention, the reaction product producing step and the reaction product removing step are continuously performed in an in-situ manner in one chamber.

The present invention relates to a dry cleaning apparatus for removing silicon oxide or silicon nitride formed on a silicon substrate, comprising: a chuck provided in a chamber and on which a silicon substrate to be processed is disposed; a chuck heating unit for heating the chuck; An RF electrode to which an RF power source is applied and has a first gas supply path, a second electrode connected to the ground terminal of the RF power source and spaced apart from the RF electrode via a plasma generation region, A showerhead having a third gas supply path physically separated from the gas supply path, and a gas heating unit for heating the gas supplied to the shower head, wherein the silicon substrate is heated by the heating temperature of the chuck heated by the chuck heating unit , And the first reaction gas including at least NF ₃ that has passed through the first gas supply path is heated by the RF power source And a second reaction gas containing at least NH ₃ is supplied to the silicon substrate in a state that the second reaction gas is not subjected to plasma treatment through the third gas supply path to be supplied to the silicon substrate through the second gas supply path, Wherein at least a part of the oxide or the silicon nitride is changed to ammonium hexafluorosilicate ((NH ₄ ) ₂ SiF ₆ ), and the heat transfer gas heated by the gas heating unit is transferred to the silicon substrate And the ammonium hexafluorosilicate is removed.

In the dry scrubber according to the present invention, the heat transfer gas may include at least H ₂ O.

In the dry cleaning apparatus according to the present invention, the heating temperature of the heat transfer gas is 200-1000 ° C.

In the dry cleaning apparatus according to the present invention, the second reaction gas is supplied in a heated state, and the heating temperature of the second reaction gas is 100-1000 ° C.

In the dry scrubbing apparatus according to the present invention, it is preferable that, in the shower head, the first gas supply passage and the second gas supply passage are provided independently of the supply path of the heated heat transfer gas supplied through the third gas supply passage of the showerhead N _2, or Ar.

In the dry cleaning apparatus according to the present invention, the temperature of the chuck is controlled at a normal temperature of -100 ° C.

According to the present invention, in order to remove silicon oxide or silicon nitride formed on a substrate, it is possible to perform a process of generating and removing ammonium hexafluorosilicate in one chamber, The present invention provides an in-situ dry cleaning method and apparatus.

Specifically, by injecting the heat transfer gas heated through the showerhead in a state where the chuck is fixed directly onto the silicon substrate to vaporize and remove ammonium hexafluorosilicate, the process speed can be increased and the failure occurrence rate can be reduced, There is provided an in-tub-type cleaning method and apparatus capable of improving instability.

FIG. 1 is a view for explaining a conventional dry cleaning technique of an Ex-situ system,
2 is a view for explaining a conventional in-situ dry cleaning technique, and FIG.
3 is a view illustrating a dry cleaning method according to an embodiment of the present invention,
FIG. 4 is a view illustrating a dry cleaning apparatus according to an embodiment of the present invention,
5 and 6 are views for explaining exemplary operations of the dry cleaning method and apparatus according to an embodiment of the present invention.

It is to be understood that the specific structural or functional description of embodiments of the present invention disclosed herein is for illustrative purposes only and is not intended to limit the scope of the inventive concept But may be embodied in many different forms and is not limited to the embodiments set forth herein.

The embodiments according to the concept of the present invention can make various changes and can take various forms, so that the embodiments are illustrated in the drawings and described in detail herein. It should be understood, however, that it is not intended to limit the embodiments according to the concepts of the present invention to the particular forms disclosed, but includes all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example, without departing from the scope of the right according to the concept of the present invention, the first element may be referred to as a second element, The component may also be referred to as a first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Other expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like are used to specify that there are features, numbers, steps, operations, elements, parts or combinations thereof described herein, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning of the context in the relevant art and, unless explicitly defined herein, are to be interpreted as ideal or overly formal Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a view showing a dry cleaning method according to an embodiment of the present invention, FIG. 4 is a view showing an exemplary structure of an apparatus in which a dry cleaning method according to an embodiment of the present invention is performed, and FIGS. 5 and 6 6 are views for explaining an exemplary operation of the dry cleaning method according to an embodiment of the present invention.

3 to 6, a dry cleaning method according to an embodiment of the present invention is a method for removing silicon oxide or silicon nitride formed on a silicon substrate 40, including a reaction product generation step (S100) and a reaction product removal Step S300.

In the reaction product production step (S100), a reaction gas which reacts with silicon oxide or silicon nitride is supplied to the silicon substrate (40) disposed in the chamber (10) to induce the reaction so that at least a part of the silicon oxide or silicon nitride Ammonium hexafluorosilicate ((NH ₄ ) ₂ SiF ₆ ) is performed. That is, after the reaction product production step (S100) is performed, all or part of the silicon oxide or silicon nitride existing on the surface of the silicon substrate 40 is replaced with the ammonium hexafluorosilicate solid layer.

For example, the reaction product generation step (S100) may include steps S110, S120, S130, S140, and S150.

In step S110, the process of disposing the silicon substrate 40 on the chuck 20 inside the chamber 10 is performed. For example, the silicon substrate 40 can be transferred to the chuck 20 inside the chamber 10 by a transfer device (not shown). The chuck 20 on which the silicon substrate 40 is disposed may be heated to a temperature of -100 DEG C at a temperature between room temperature and 100 DEG C by using the chuck heating unit 30, As shown in Fig. Since the silicon substrate 40 is placed in contact with the chuck 20, the silicon substrate 40 is heated to a temperature corresponding to the heating temperature of the chuck 20. [

In step S120, a process of injecting the first reaction gas into the plasma generation region is performed. For example, the first reaction gas may include at least NF ₃ , and more specifically, NF ₃ , O ₂ , He, and Ar. For example, the first reaction gas may be injected from the top of the chamber 10 into the plasma generation region, and for this purpose, the RF electrode 60 disposed in the upper region of the chamber 10 is supplied with the first reaction gas A first gas supply path 62 for providing an injection path may be provided.

In step S130, a process of generating a plasma in the plasma generation region by applying the RF power source 50 is performed. For example, the RF electrode 60 may be disposed on the upper side of the chamber 10, and the showerhead 70 may be disposed on the lower side of the chamber 10 with the plasma generation region interposed therebetween. May be electrically connected to the RF electrode 60 and the cathode may be electrically connected to the showerhead 70. When the RF power source 50 is applied, the first reaction gas injected into the RF electrode 60 and the showerhead 70 is radiated by the plasma reaction and is supplied to the second gas supply path 72 to the silicon substrate 40.

In step S140, a process of directly injecting the second reaction gas into the showerhead 70 without plasma processing and supplying the second reaction gas to the silicon substrate 40 is performed. For example, in addition to the second gas supply path 72 for providing a path through which the radicalized first reaction gas passes, the showerhead 70 disposed below the plasma generation region may further include a second reaction gas, And the third gas supply path 72 and the third gas supply path 74 may be provided with a path that is physically separated from the first gas supply path 72. [ . For example, the second reaction gas may comprise at least NH ₃ , and more specifically NH ₃ , H ₂ .

For example, the second reaction gas may be configured to be supplied in a heated state at a temperature of 100-1000 占 폚. The reason for such a configuration will be described as follows. Generally, in order to remove silicon oxide or silicon nitride formed on a silicon substrate, NF ₃ and an inert gas are injected into a plasma reaction region to generate fluorine radicals, and NH ₃ or H ₂ gas is supplied to the silicon To the substrate. At this time, the degree of activation of hydrogen is influenced by the fluorine radical. This method has a problem of low hydrogen activation efficiency and difficult control. 6, an embodiment of the present invention provides a method for controlling the level of hydrogen activation required for the formation of an ammonium hexafluorosilicate solid layer by controlling the temperature of a second reaction gas, such as NH ₃ or H ₂ , And it is possible to perform precise control through fine temperature variation.

In step S150, the process in which the plasma-treated first reaction gas and the non-plasma-treated second reaction gas react with silicon oxide or silicon nitride formed on the silicon substrate 40 to produce ammonium hexafluorosilicate as a reaction product . For example, ammonium hexafluorosilicate may be produced as a solid layer, and all or a portion of the silicon oxide or silicon nitride present on the surface of the silicon substrate 40 may be replaced by an ammonium hexafluorosilicate solid layer .

For example, in the case where silicon oxide is formed on the silicon substrate 40, by the reaction of the radical components contained in the first reaction gas supplied by the plasma treatment and the gas components of the second reaction gas supplied without plasma treatment The process by which the silicon oxide is changed to ammonium hexafluorosilicate is described as follows.

2 NH ₄ F (g) + ₄ HF (g) + SiO ₂ = (NH ₄ ) ₂ SiF ₆ (g) + 2H ₂ O

In the reaction product removing step (S300), a process of removing ammonium hexafluorosilicate by supplying a heated heat transfer gas to the silicon substrate 40 on which ammonium hexafluorosilicate is formed is performed.

For example, the heat transfer gas may comprise a H ₂ 0 at least the heating can be more specifically, includes a heating H ₂ 0, N _2.

The heating temperature of the heat transfer gas may be 200-1000 캜. By structuring the heating temperature of the heat transfer gas in this manner, ammonium hexafluorosilicate can be effectively vaporized and removed.

For example, in the reaction product removing step S300, a reaction gas containing N ₂ or Ar is supplied through a path which is independent of the supply path of the heated heat transfer gas supplied through the showerhead 70 provided in the chamber 10 Gas can be supplied.

The process of vaporizing and removing ammonium hexafluorosilicate by the heated heat transfer gas is described as follows.

_{(NH 4) 2 SiF 6 (} g) = SiF 4 (g) + 2NH 3 (g) + 2HF (g)

The conventional Ex-situ dry cleaning technique described with reference to FIG. 1 is a method in which ammonia hexafluorosilicate is produced in a reaction chamber, the substrate is transferred to a heat treatment chamber, and placed in a chuck heated to 120 ° C or higher, According to this technique, a bottleneck of the transfer device during repeated processes to remove oxides or nitrides of a certain thickness or more can be prevented. In addition, the present invention relates to a technique for removing ammonium hexafluorosilicate at a temperature using heat conduction from a chuck to a substrate, There is a problem that productivity is lowered due to occurrence of a phenomenon.

The conventional in-situ dry cleaning technique described with reference to FIG. 2 is a technique for simultaneously performing a reaction for generating ammonium hexafluorosilicate in one chamber and a heat treatment for removing ammonium hexafluorosilicate, The bottleneck problem is improved over the conventional Ex-situ method, but since the process of bringing the chuck close to the heated showerhead for heat treatment has to be performed, the limitation of the moving speed due to the weight of the lower module including the chuck, There is a problem that the overall productivity is deteriorated including the unit per hour (UPH) and the mean time between failure (MTBF) due to the failure due to the progress.

However, according to an embodiment of the present invention, a process of generating and removing ammonium hexafluorosilicate in one chamber is performed, and a heat transfer gas heated through a showerhead is sprayed onto the silicon substrate while the chuck is fixed, Since ammonium fluorosilicate is removed, the process speed is increased and the rate of occurrence of faults is remarkably reduced, which can improve productivity and hardware instability of the prior art.

For example, in the process of removing ammonium hexafluorosilicate, the chuck 20 with which the silicon substrate 40 is placed in contact may be in a heated state, Since it is heated to a temperature corresponding to the heating temperature, the removal efficiency of ammonium hexafluorosilicate can be increased.

For example, the heating temperature of the showerhead 70 may be 100-200 占 폚, and the heating temperature of the inner wall of the chamber 10 may be 80-100 占 폚.

As described above, according to one embodiment of the present invention, the reaction product production step (S100) and the reaction product removal step (S300) can be continuously performed in an in-situ manner in one chamber.

FIG. 4 is a view showing a dry cleaning apparatus according to an embodiment of the present invention, and FIGS. 5 and 6 are views for explaining an exemplary operation of a dry cleaning apparatus according to an embodiment of the present invention.

4 to 6, an embodiment of the present invention is a dry cleaning apparatus for removing silicon oxide or silicon nitride formed on a silicon substrate 40, including a chamber 10, a chuck 20, a chuck heating unit 30, an RF electrode 60, a showerhead 70, and a gas heating unit 80. 4 to 6, other components may be included in the dry scrubbing apparatus, but components that are not relevant to the features of the present invention are omitted from FIGS. 4 to 6. FIG. Further, it is to be noted that the dry cleaning apparatus according to an embodiment of the present invention is an exemplary apparatus configuration for performing the dry cleaning method described in detail above, and description of the method can be applied to the apparatus.

The chamber 10 provides a space in which the entire process of removing silicon oxide or silicon nitride formed on the silicon substrate 40 is performed.

The chuck 20 is a component which is provided inside the chamber 10 and on which the silicon substrate 40 to be processed is disposed.

The chuck heating section 30 is a component that heats the chuck 20.

The RF electrode 60 is disposed in an upper region of the chamber 10 and is provided with a first gas supply path 62 to which an RF power source 50 for generating plasma is applied.

The showerhead 70 is electrically connected to the ground terminal of the RF power supply 50 and is spaced apart from the RF electrode 60 with the plasma generation region therebetween. The second gas supply path 72 and the second gas supply path And a third gas supply passage 74 that is physically separated from the second gas supply passage 72. [ Since the showerhead 70 is connected to the ground terminal of the RF power source 50 and is grounded, only the reactive radical component can pass through while suppressing the ion component injected into the silicon substrate 40 as much as possible.

When the RF power source 50 is applied, the first reaction gas injected into the RF electrode 60 and the showerhead 70 is radiated by the plasma reaction and is supplied to the second gas supply path 72 to the silicon substrate 40.

The gas heating unit 80 is a component for heating the gas supplied to the shower head 70.

The silicon substrate 40 is heated in response to the heating temperature of the chuck 20 heated by the chuck heating section 30. In this case,

The first reaction gas including at least NF ₃ that has passed through the first gas supply path 62 is plasma-treated by the RF power supply 50 and is supplied to the silicon substrate 40 through the second gas supply path 72 And a second reaction gas containing at least NH ₃ is supplied to the silicon substrate 40 without being subjected to the plasma treatment through the third gas supply path 74 so that at least a part of the silicon oxide or silicon nitride is oxidized by the hexafluoro is changed into ammonium silicate _{((NH 4) 2 SiF 6} ).

Further, the heat transfer gas heated by the gas heating unit 80 is injected into the silicon substrate 40 through the third gas supply path 74, and ammonium hexafluorosilicate is vaporized and removed.

For example, the first gas supply path 62 and the second gas supply path (not shown) may be provided independently of the supply path of the heated heat transfer gas supplied through the third gas supply path 74 of the shower head 70 72 may be supplied with a gas containing N ₂ or Ar that has not been subjected to plasma treatment.

As described in detail above, according to the present invention, it is possible to perform a process of generating and removing ammonium hexafluorosilicate in one chamber in order to remove silicon oxide or silicon nitride formed on a substrate, There is an effect that an in-situ dry cleaning method and apparatus capable of improving the cleaning efficiency can be provided.

Specifically, by injecting the heat transfer gas heated through the showerhead in a state where the chuck is fixed directly onto the silicon substrate to vaporize and remove ammonium hexafluorosilicate, the process speed can be increased and the failure occurrence rate can be reduced, There is provided an in-tub-type cleaning method and apparatus capable of improving instability.

10: chamber
20: chuck
30: chuck heating section
40: silicon substrate
50: RF power
60: RF electrode
62: a first gas supply path
70: Shower head
72: second gas supply path
74: third gas supply path
80: gas heating section
S100: reaction product production step;
S200: reaction product removal step

Claims (16)

delete delete delete delete delete delete delete delete delete delete 1. A dry cleaning apparatus for removing silicon oxide or silicon nitride formed on a silicon substrate,
A chuck fixed in the chamber and having a silicon substrate to be processed disposed therein;
A chuck heating section for heating the chuck;
An RF electrode to which a RF power source for plasma generation is applied and has a first gas supply path;
And a third gas supply path which is separated from the RF electrode and is physically separated from the second gas supply path and the second gas supply path while being connected to the ground terminal of the RF power supply, Shower head; And
And a gas heating unit for heating the gas supplied to the showerhead from the outside of the chamber,
The silicon substrate is heated in response to a heating temperature of the chuck to be heated by the chuck heating unit,
Claim that the first reaction gas containing at least NF ₃ having passed through a first gas supply wherein the plasma processing by the RF power is supplied to the silicon substrate via a second gas supply, comprising at least NH ₃ 2 reaction gas is heated outside the chamber by the gas heating unit and supplied to the silicon substrate without being plasma-treated through the third gas supply path so that at least a part of the silicon oxide or the silicon nitride is hexafluorosilicic acid Ammonium ((NH ₄ ) ₂ SiF ₆ )
A heat transfer gas heated from the chamber by the gas heating unit is injected to the silicon substrate through the third gas supply path to remove the ammonium hexafluorosilicate,
Wherein the step of changing at least a part of the silicon oxide or the silicon nitride to the ammonium hexafluorosilicate and the step of removing the ammonium hexafluorosilicate are carried out in a single chamber by using an In- situ manner. < / RTI > 12. The method of claim 11,
The heat-conducting gas, the dry cleaning apparatus comprises at least H ₂ 0. 12. The method of claim 11,
Wherein the heating temperature of the heat transfer gas is 200-1000 ° C. 12. The method of claim 11,
Wherein the heating temperature of the second reaction gas is 100-1000 占 폚. 12. The method of claim 11,
A gas containing N ₂ or Ar is supplied through the first gas supply path and the second gas supply path independently of the supply path of the heated heat transfer gas supplied through the third gas supply path of the shower head Wherein the cleaning device is a dry cleaning device. 12. The method of claim 11,
Wherein the temperature of the chuck is controlled at a normal temperature of -100 ° C.

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