KR0145032B1 - Mounting apparatus for cryogenic aerosol cleaning - Google Patents

Abstract

An apparatus for mounting a tool having a surface to be cleaned to generate an aerosol for cleaning the surface from a substance includes a flange for mounting a tool having a surface to be cleaned. The flange is equipped with a nozzle for accommodating the substance. In order to solidify at least a substantial portion of the substance to produce the surface cleaning aerosol, the substance is subjected to a first pressure. at least one exit opening to allow passage of the material so that it can expand from a first pressure to a second pressure lower than the first pressure. And condensation preventing means for preventing the formation of condensation on the surface of the object to be cleaned, wherein condensation preventing means is provided. Then it is provided with contamination prevention means (contamination preventing means) for preventing contamination of the re-contaminate the surface.

Description

Tool mounting and aerosol generator

1 is an overall schematic diagram of an aerosol cleaner

2 is a partial cross-sectional view of a heat exchanger according to the present invention.

3 is a partial cross-sectional view of the heat exchanger of FIG.

4 is a cross-sectional view of the insulation used in the heat exchanger of FIG.

5 is a cross-sectional view of an embodiment of a surface cleaning apparatus according to the present invention.

6 is a front partial cross-sectional view of a nozzle tip according to the present invention.

7a-b are different views of the nozzle tip of FIG.

8 is a cross-sectional view of another embodiment of a surface cleaning apparatus according to the present invention.

9 is a plan view of the surface cleaning apparatus of FIG.

FIG. 10 is a bottom view of the surface cleaning apparatus of FIG.

11 is a cross-sectional view of a nozzle tip in accordance with the present invention.

12A-C illustrate exemplary nozzles that may be used in accordance with the present invention.

13 is a cross-sectional view of another embodiment of a surface cleaning apparatus according to the present invention.

14 is a plan view of the surface cleaning apparatus of FIG.

* Explanation of symbols for main parts of the drawings

15, 102, 202, 330: Nozzle 20: Surface to be cleaned

210,305: Tool chamber 222: Gloves

223: valve 225: cover

2330,300 Flange 240,310 Purification port

242,315: Purified gas supply part 245, 320: Outlet port

247,325 vacuum pump 249,326 pressure regulator

260: supply line 264, 340: swivel joint

275,345: Access opening

The present invention relates to the preparation of cryogenic aerosol, and more particularly to a surface cleaning apparatus using a low temperature aerosol.

Surface contamination is of broad interest in various industries. Such surface contamination may lead to the production of inferior or non-operating products or may result in significantly lower production rates. For example, as a specific example, surface contamination is a problem that often occurs in the microelectronics processing industry, and may appear in the form of undesirable particles, films, molecules, and the like; Surfaces that may be contaminated include surfaces such as semiconductor wafers, displays, and microelectronic components. Such surface contamination can cause various types of defects, especially short circuits, open circuits and stacking faults, among others, which can adversely affect the circuit and ultimately This can cause failure of the entire chip.

Other types of surfaces with contaminants that need to be removed include walls of tool or process chambers, such as plasma etching and chemical neutralization reactors. Reaction residues and / or polymers generated during semiconductor fabrication tend to deposit on the chamber walls. Such residues and / or polymers may then fall onto or under the product being manufactured. In order to prevent a decrease in production rate caused by such a mechanism, it is necessary to periodically dismantle and clean or wipe the manufacturing process chamber. The current practice is to break down fixtures inside the chamber every week and wipe down all surfaces with a mixture of alcohol and water. Such periodic mechanical disassembly, wiping and fabrication operations, and the long pump-down times required for surface drying after cleaning, severely degrade the manufacturing and reliability of processing equipment. In addition, the acidic fumes formed when the deposited material reacts with water often pose a risk to the health of the cleaning personnel.

United States Patent No. 5,108,512, issued to goffnett et al. On April 28, 1992, relates to cleaning a chemical vapor deposition reactor used for the production of polycrystalline silicon by impinging on carbon dioxide pellets. will be. This US patent discloses the transfer of carbon dioxide gas to a pelletizer where it is compressed to form solid carbon dioxide pellets. This pellet is sent to the nozzle with an accelerant gas to increase its speed. This nozzle is a venturi nozzle that maximizes the speed of pellets being discharged there. Moreover, this nozzle is mounted on a conveyor arm that allows movement of the nozzle. The drawbacks of this US patent cleaning device include the need for a pelletizer and the need to mount the nozzle on the conveyor arm in order to move the nozzle. In particular, the conveyor arm arrangement limits the mobility of the nozzle because the nozzle can only be moved according to the structure of the conveyor arm.

Another type of cleaning method is a chemical cleaning method used to clean particulate and / or film contaminants from surfaces such as wafers and substrates. This chemical cleaning method involves the use of a solvent or liquid cleaning agent to dissolve or transfer contaminants from the surface to be cleaned. The drawback of this chemical cleaning method is that the cleaning agent must be maintained at a high degree of cieanliness and purity. Therefore, a high quality cleaning agent is required, and the cleaning agent needs to be replaced periodically because the contamination gradually increases during cleaning. Replaced chemicals must be disposed of, causing environmental pollution. Therefore, it is difficult and expensive to implement chemical cleaning methods properly and efficiently.

U.S. Patent No. 5,062,898, issued to Nov. 5, 1991 by MC Dermott et al. And co-assigned to the applicant, discloses microelectronics using an aerosol of at least approximately solid argon particles impinging on the surface to be cleaned. And to clean the surface of the device.

Pending US patent application Ser. No. 07 / 970,346, filed November 2, 1992 and co-assigned to the applicant, discloses microelectronic device surfaces using an aerosol of at least approximately solid argon or nitrogen particles impinging on the surface to be cleaned. It is about cleaning.

United States patent application Ser. No. 07 / 958,417, filed Oct. 9, 1992, patented Dec. 14, 1992, and shared with the present applicant is disclosed in U.S. Patent No. 5,062,898 or United States Patent Application No. 07 / 970,346. Low temperature as

The present invention relates to an apparatus capable of performing a cleaning method with an aerosol.

In general, the present invention relates to an apparatus for producing a surface aerosol from a substance, as well as mounting a tool having a surface to be cleaned. The apparatus has a flange for mounting a tool having a surface to be cleaned. The flange is equipped with a nozzle for receiving the material. The nozzle is adapted to solidify at least a substantial portion of the material to produce the surface cleaning aerosol, wherein the material is from a first pressure to a second pressure lower than the first pressure. It has at least one exit opening that allows passage of the material so that it can expand. Condensation preventing means are provided for preventing condensation from forming on the surface of the device and the surface of the object to be cleaned, and after removal of the contaminants from the surface, the contaminants recontaminate the surface. Contamination preventing means are provided to prevent this.

These and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the invention and will be better understood.

In general, aerosol cleaning of contaminated surfaces is performed through a process of colliding cryogenic particles at high speed with the surface to be cleaned. These low temperature aerosol particles collide with contaminating particles, films and molecules on the surface. This collision imparts sufficient energy to the contaminant so that the pollutant is released from its surface. Emitted pollutants enter and exit the gas stream. The gaseous phase of the aerosel strikes and flows across the surface to form a thin boundary layer. This contaminant is usually present in the low speed boundary layer. Thus, this gaseous aerosol alone does not remove small contaminants because of its insufficient shear force. However, low temperature aerosol particles have a significant inertia and can therefore cross the surface through the boundary layer.

Low temperature aerosol particles tend to slow down as they pass through the boundary layer towards the surface. In order to cause the cleaning, aerosol particles must hit the surface across the boundary layer. As a simple model, suppose that the gas flow produces a boundary layer of thickness h with a negligible normal component of velocity. To hit the surface, the solidified low temperature aerosol particles must enter the boundary layer within a normal velocity component equal to at least h / t. The particle relaxation time t is given by the following equation.

Where a is the radius of the low temperature aerosol particles, ρ _p is the particle density, u is the dynamic viscosity of the gas, and C is the Strokes-Kuningham slip correction factor defined by the equation cunningham slip correction factor.

In this equation, is the mean free path of the gas molecules inversely proportional to the gas pressure.

The above analysis shows that the efficiency of the cleaning process depends on the size of the low temperature aerosol particles. This cleaning process is more efficient for low temperature aerosol particles with large masses or high initial rates. However, large aerosol particles are likely to damage fragile structures on the surface being cleaned, such damages may include fitting, cracking, dislocations and stresses. have. Furthermore, when the low temperature aerosol particles become large, these particles cannot penetrate into the depression areas or trenches of the structure in order to efficiently remove contaminants.

Low temperature aerosol particles are formed during the expansion process. Temperature drops associated with expansion nucleate and condense gaseous or liquid species into at least nearly solid particles. This nucleation occurs when the gas / liquid vapor is saturated and the partial pressure exceeds the equilibrium vapor pressure. The stable size of the nucleus formed during this process is given by the following equation.

Where is the surface tension; v ₁ is the molecular volume of the nucleated kind; k is the boltzmann constant; T is the temperature at which nucleation occurred. S is the saturation ratio of the condensable species reached during expansion and cooling. At the same time, rapid condensation and growth from diffusion into the nuclei of the vapor molecules occur, thereby enhancing the size of the low temperature aerosol particles.

The above analysis controls the expansion parameters such as pressure and temperature of gaseous or liquid species before and after expansion to produce the desired low temperature aerosol particles to achieve damage-free cleaning performance. It proves important to do.

Inert materials that have been shown to be effective in producing low temperature aerosols for cleaning various surfaces include carbon dioxide, argon and nitrogen.

Referring to FIG. 1, a device capable of producing low temperature aerosols for cleaning or sand blasting a contaminated surface has a source 5 of gas, liquid or gas / liquid, which aerosols It is produced from gas, liquid or gas / liquid. The material supplied from this source 5 should be a material that is not harmful to the surface 20 to be cleaned and produces an aerosol having a degree of purity according to the required cleanliness of the surface 20. Should be. For example, wafers for manufacturing microelectronics require very clean, so cleaning of such wafers may require very pure aerosols; plasma tool chambers may not require high cleanliness, Aerosols used to clean the chamber may not require as high a purity as those used for wafer cleaning.

Generally, aerosols generated from gaseous liquids or gas / liquids can clean various contaminated surfaces, but it is desirable to produce aerosols from gases when high purity aerosols are needed, and liquids or when aerosols of relatively low purity are required It is desirable to produce an aerosol from gas / liquid. In this regard, a heat exchanger 10 is required when producing aerosol from gas, but no heat exchanger is needed to generate aerosol from low temperature liquid or gas / liquid. Thus, it is generally cheaper to produce aerosols from cold liquids or gases / liquids.

As mentioned above, inert materials that have been found to be effective in producing aerosols for cleaning various surfaces include carbon dioxide, argon and nitrogen. For example, at least nearly solid argon particle containing aerosols produced from argon gas have proven to be efficient for cleaning silicon wafers. Argon gas may be used alone or in combination with ultrapure nitrogen gas, in the latter case nitrogen gas may be made to remain in the gas phase and a carrier which imparts a high velocity to the solid argon particles to be produced. It serves as. Mixing nitrogen and argon increases the expansion rate, thus increasing the joule-Thompson effect and improving cooling. This nitrogen gas may serve as a diluent to produce argon aerosol particles of different sizes when it is mixed with argon before expansion. Such gases may be mixed and optionally filtered and / or cooled to some extent before being sent to the heat exchanger for further cooling.

As another example, aerosols generated from carbon dioxide liquids, argon liquids, or nitrogen liquids have been found to be effective for cleaning plasma tool chambers. When producing an aerosol from a liquid or gas / liquid, it is important that this material is fed directly to the nozzle 15, ie without passing through the heat exchanger 10.

When producing an aerosol from the gas, the gas is supplied from the source 5 to the heat exchanger 10. This will be described later in more detail. In general, the heat exchanger 10 is responsible for bringing the gas into the vicinity of a liquefaction or solidification, i.e. within about 5-20 above the liquid and / or solid transition temperature of the gas. Cool to temperature. However, it is important that most of the gas be kept in a gaseous state upon passage of the heat exchanger 10. This heat exchanger 10 may also serve as an impurity trap to remove condensable impurities from the gas passing therethrough. Typically, a cooled gas, such as argon gas, has a temperature of about -190 ° F to -300 ° F at a pressure of about 20 psig to 690 psgi, preferably about -250 ° F to -300 ° F and about 20 psig. To 100 psig.

Thereafter, the cooled gas that has passed through the heat exchanger 10 or a substance which may be a liquid or a gas / liquid supplied directly from the source 15 is supplied to the nozzle 15. In this nozzle the material is adiabatically expanded to a lower pressure, causing at least a substantial portion of the material to solidify and orient towards the surface to be cleaned 20. The nozzle 15 will be described in more detail below. The pressure of the expanded material may be possible from a high vacuum to a range above atmospheric pressure. This expansion leads to Joule-Thompson cooling of the substance, which preferably results in the solidification of the material and thus the formation of aerosols. However, although solidification of the material preferably occurs, some of the material may instead be liquefied or remain liquid. In this regard, the surface 20 can be efficiently cleaned even if at least a substantial portion of the material is formed of solid particles and the remainder of the material remains liquid.

If the gas is compressed below its triple point it will form solid particles directly without first forming liquid droplets. If this gas is not compressed below its triple point, the gas will be liquid. It may be condensed into droplets and retained as a liquid, or may be frozen into solid particles if the pressure drop is appropriate. In an example, the triple point of argon gas is -308.9 to 9.99 psia. Moreover, the liquid will form solid particles if sufficient cooling is achieved.

Referring to FIG. 2, there is shown a heat exchanger 10 that can provide cooling conditions as outlined above. The heat exchanger 10 has a cryogenic reservoir 25 mounted in the housing 30. Since the cold storage container 25 can be mounted in the housing 30 by a number of conventional means, such conventional means are not shown and will not be described in detail. However, in order to maximize efficiency, it is preferable that the low temperature storage container 25 is not in contact with the inner wall of the housing 30. In this regard, the low temperature reservoir 25 can be separated from the inner wall of the housing 30 by placing a suitable insulating material therebetween.

The cold storage container 25 preferably comprises a solid material, which is efficient and efficient for the heat exchanger 10 to accurately control the gas temperature to within, for example, 2-3 ° F. of the desired temperature. In order to be able, the low temperature storage container 25 should have a high thermal conductivity, a relatively large specific heat value and a suitable size or weight. Consideration should be given to problems related to manufacturing rates, for example brazing. The type of material used and the mass it requires is determined by the allowable temperature fluctuation and cooling energy conditions of the cold storage container 25 during the manufacture of the aerosol. For example, it has been found that a copper block weighing approximately 2391bs has the necessary properties to serve as the cold storage container 25 in some applications. The temperature at which the cold reservoir 25 is to be maintained is a function of the operating pressure of the gas. Typically, the cold reservoir 25 is maintained at a temperature of about -260 ° F to -300 ° F. The higher the operating pressure of the gas, the higher the temperature at which the cold storage container 25 should be maintained, and vice versa. Four heat sensors 31-34 are positioned along the length of the cold storage container 25 to monitor the temperature of the cold storage container 25, and the temperature monitored from the heat sensor controls the temperature of the gas. Used to adjust.

The gas to be cooled enters the inlet 40 and passes through a cooling tubing 45, where the cooled gas is discharged to the outlet 50. It must have a suitable length and a suitable diameter to properly cool down to the required temperature when it reaches. In one embodiment, the tube 45 may comprise stainless steel or other suitable material and may have an outer diameter of 3/8 inch and a length of about 32 feet, the gas first being within 24 feet of the tube 45. It has been found that the cooling can be cooled to within about 2-3 ° F. of the low temperature storage vessel 925. The gas is maintained at this temperature as it passes through the remaining length of the tube 45.

Moreover, the inner surface of the tube 45 must be sufficiently cleaned so that the gas passing through it is not contaminated. For example, the inner surface of the tube 45 may be chemically cleaned and electropolished by conventional methods.

The tube 45 must have sufficient thermal contact with the low temperature storage container 25 so that the cooling energy of the low temperature storage container 25 can be efficiently and efficiently transferred to the gas via the tube 45. In this regard, in order to carry out the transfer of cooling energy, at least a portion of the tube 45 is placed in physical contact with or at least physically close to the cold storage 25 along the entire length of the tube, so that the tube 45 It is desirable to allow the gas passing through) to be in physical proximity to the cold storage container 25. Accordingly, the heat energy of the gas is exchanged with the cooling energy of the cold storage container 25 through the tube 45, so that the gas is cooled.

3 illustrates one embodiment of how the tube 45 can be positioned and positioned to provide sufficient thermal contact with the cold reservoir 25. In particular, a spiral radial groove 55 is machined in and around the cold reservoir 25. This helical groove 55 has a suitable dimension to accommodate the tube 45 so that a substantial portion of the tube 45 contacts or solders the cold reservoir 25 within the groove 55. You must be able to contact them. In some cases, through cutting, a notch 60 can be formed in the groove along the entire length of the groove 55.

During assembly, a brazing wire is placed in the notch 60 and the tube 45 is swung in the groove 55 around the cold storage container 25. Thereafter, another soldering wire is placed along the length of the tube 45 on the outside of the groove 55. The low temperature reservoir 25 is then placed together with the tube 45 and the soldering wire in a vacuum curing oven, for example, to bond the tube 45 to the low temperature reservoir 25. Melt the solder wire to form. In particular, the solder wire in notch 60 melts to provide adhesion of tube 45 by filling notch 60; Solder wires located along the length of the tube 45 on the outside of the grooves 55 melt and flow between the tube 45 and the inside of the grooves 55 to form an adhesive therebetween. The tube 45 is sufficiently in contact with the low temperature storage container 25 so that sufficient thermal contact with the low temperature storage container 25 is achieved, and thus the efficient exchange of cooling energy from the storage container 25 to the gas through the tube 45. Or delivery must occur.

In order to achieve the required temperature and stability as described above, the low temperature reservoir 25 and the tube 45 and the gas in the tube 45 are insulated by suitable insulating means 30. It is located within) and is isolated from the conduction and conduction heat input and radiation heat load, or protected from cold energy loss. For example, the insulation means may comprise layered insulation means surrounding the element in the housing 30 and / or the housing 30 itself; the insulation means removes molecules from the housing 30. It may further include a vacuum insulation means.

In one embodiment, the layered insulation means comprises a material surrounding the housing 30 or wrapped around the housing 30. The material should then be able to serve as a barrier to reduce the influx of radiant heat and to prevent conduction. In a preferred embodiment, in order to construct the layered insulation means of the present invention, WBoroski, J.D. Gonczy of Fermi National Accelerator Laboratory and Researched by rcniemann and presented by J. D. Gonchi at the International Industrial Symposium on the Super Collider in New Orleans, Louisiana, February 8-10, 1989. And the concept disclosed in the article Multilayer Insulation (MLI) in the Superconduction Super Collider-a Practical Engineering Approach to Physical Parameters Governing MLIThermal Performance, published in March 1989. According to this concept, the layered insulation means may comprise a multilayered blanket 85, a part of the planar cross-sectional view of the blanket shown in FIG. The multilayer blanket 85 has alternating layers of reflective layers 90 and spacer layers 95, and the multilayer blanket 85 starts with a spacer layer 95 and then a spacer layer. Ends with 95. Each reflective layer 90 has an intermediate portion 92 comprising a material having a low emissivity to serve as a barrier to conduction. The middle portion 92 of each reflective layer 90 is sandwiched between two end layers 93 and 94. Each end layer 93, 94 includes a material capable of reflecting thermal energy. The spacer layer 95 serves to space the reflective layers 90 apart from each other, and thus surrounds the end layers 93 and 93 so that heat is not transferred directly from one reflective layer 90 to the other reflective layer 90. The specific total number of alternating reflective and spacer layers needed for the multilayer blanket 85 to function effectively depends on the particular application in which the multilayer blanket is used. In general, the heat flux passing through the multi-faceted blanket 85 varies inversely to the number of reflective layers 90 implemented, and the density or number of reflective layers 90 per unit thickness of the blanket 85. Function. In a particular embodiment, in order to provide an efficient blanket 85 for functioning as a layered thermal insulation means for generating aerosols in the specific temperature ranges described above, 21 spacer layers 95 are interposed between the 20 reflective layers 90. Stitched together alternately, each reflecting layer 90 has an emissivity of less than about 0.03 and a thickness of about 1/4 mil, and the middle portion 92 of each reflecting layer contains polyester, The monolayers 93 and 94 comprise an aluminized metal coating having a thickness of about 350 Angstroms, each spacer layer 95 having a thickness of about 4 mils and a density of about 0.5 oz / yd ² . It has been found suitable to include polyethylene terephthalate or spunbonded polyester.

By way of example, a pump 65 may be provided to evacuate gas molecules from the housing 30 to form a high vacuum in the housing 30, for example about 1 × 10 ⁻⁴ torr. The pump 65 may be a Turbo-V60 Turbomolecular Pump, No. 969-9002, commercially available from varian vacuum product of Lexington, Massachusetts. However, other commercially available pumps may be used to achieve the desired vacuum level. Furthermore, in order to increase the cooling efficiency, the pump 65 is mounted on a 90 degree elbow 70 so that the mouth of the pump 65 is directed toward the inside of the housing 30. It may be possible to avoid direct orientation. In this regard, an elbow at 90 degrees minimizes the transfer of all heat into the housing 30 that may be generated by the pump 65 during operation.

In order to cool the cold storage container 25 to a desired temperature, a cooling element extends into the housing 30 and preferably extends into the cold storage container 25 and / or in contact with the cold storage container 25. Cooling means 75, such as a cold head, with elements 77 are provided. This cooling means 75 may be any commercially available cooling device capable of cooling the cold storage container 25 at a constant rate until the desired temperature is reached. For example, the Balzers Model 150 Cryogenic Refrigerator, commercially available from Balzers, Hudson, New Hampshire, USA, is a closed cycle refrigerator capable of transmitting 200 watts of power at 77 ° K. to be. According to this cooling means, the low temperature storage container 25 containing 239 pounds of copper blocks can be cooled from room temperature to 77 ° K in approximately 9 hours, and the minimum temperature is about 24 ° K. This heat exchanger 10 allows a large heat loads of gas to be maintained within a small deviation of the desired low temperature. For example, for a process heat load of about 1200 Watts / minute, it has been found that the output temperature of the gas can be maintained and controlled within +/- 1 ° F of the desired temperature.

Furthermore, in order to maintain the low temperature storage container 25 accurately at the desired temperature, a heating rod extending into the housing 30 and preferably extending into the low temperature storage container 25 or in contact with the low temperature storage container 25 ( Heating means, such as conventional heat worms (not shown), with heating rods 80 may be provided. The cold head and / or heat source may be turned on and off periodically to achieve that goal. In this regard, the low temperature reservoir 25 can be maintained at a desired temperature without heating means by turning the cooling head on and off at appropriate intervals.

In addition, the heat exchanger 10 of the present invention can be used as a heating device in place of the cooling device when the heating means is used instead of the cooling means 75. Currently commercially available heat sources can be used to achieve this purpose. In such a case, the low temperature storage container 25 may be referred to as a heating storage container rather than a low temperature storage container.

Moreover, the apparatus of the present invention can function as a heat exchanger and / or purifier or an impurity collector. While the temperature of the gas is reduced to a lower temperature in the tube 45, all impurities contained in the gas having a transition temperature above the holding temperature will condense on the inner wall of the tube 45. This also applies to the liquid passing through the tube 45 as well. In this regard, it should be noted that in the case of serving as an impurity collector, regeneration means must be included to remove impurities condensed on the inner wall of the tube 45. In this regard, heating means such as a conventional heat source (not shown) with a heating rod 80 extending into the housing 30 can be used to raise the temperature of the cold storage container 25 above the transition temperature of impurities. And the impurities removed at that time can be removed from the tube 45.

Following cooling by the heat exchanger 10, the gas is sent to a nozzle 15, which produces an aerosol and directs the aerosol to the surface 20 to be cleaned. This nozzle 15 should be able to efficiently provide the required Joule-Thomson cooling of the gas so as to solidify at least a substantial portion of the gas to produce the aerosol. According to the invention, various means for mounting the nozzle 15 may be implemented differently depending on the particular application and the surface to be cleaned.

5-7, in one embodiment, a nozzle apparatus having a nozzle 102 includes a surface 20 to be cleaned, for example a process chamber 105 having a wafer located therein. It is mounted on. This surface 20 can be moved under the nozzle 102 using, for example, a chuck 110 on which the surface rests. Thus, the resulting aerosol is oriented to the surface 20, and the surface 20 is cleaned because it moves under the nozzle 102. Moreover, when the surface 20 is cleaned, a curtain made of, for example, nitrogen Gas or carrier gas may flow through the process chamber 105 as indicated by arrow 115. Particles cleaned from the surface 20 can be carried away by the curtain gas. Moreover, the curtain gas may function to minimize the formation of moisture, icing or impurity condensation on the surface 20 due to the aerosol oriented to the surface 20. The formation of moisture or freezing can cause inadequate cleaning of the surface 20. The surface 20 may also be heated by conventional heating means to keep it dry.

As shown, the nozzle 102 is connected to one end of a delivery line 120. The other end of the transfer line 120 is connected to the tube 45 from the heat exchanger 10; or, if the substance does not require cooling prior to transfer to the nozzle 102, a substance supply and Can be connected directly. The feed line 120 is housed in a vacuum feedthrough assembly 125. One end of the vacuum application assembly 125 is mounted to the heat exchanger 10; The other end of the vacuum application assembly 125 is mounted to a chamber cover 130 of the process chamber 105. This chamber cover 130 has a nozzle housing 135 extending into the process chamber 105. The vacuum application assembly 125 is in communication with the heat exchanger 10, the nozzle housing 135 of the chamber cover 130 is in communication with the vacuum application assembly 125, and formed in the housing 30 of the heat exchanger 10. It is desirable for the vacuum to be realized in the vacuum application assembly 125 and also to be realized in the nozzle housing 135. Thus, the vacuum application assembly 125 is hermetically mounted to the housing 130 such that the pump 65 can be used to create a vacuum in the vacuum application assembly 125 and the nozzle housing 135 as well as the housing 30. The chamber cover 130 of the process chamber 105 should be sealingly mounted to the vacuum application assembly 125. Such mounting and sealing can be accomplished by conventional means and will not be further described in the present invention. The vacuum level of the vacuum application assembly 125 and the nozzle housing 135 may be maintained at about the same as the vacuum level in the housing 30, for example at approximately 1 × 10 ⁻⁴ torr. In order to insulate and / or isolate the conveying line 120 and the nozzle 102 from the atmosphere, a vacuum is provided in the vacuum application assembly 125 and the nozzle housing 135 to provide a tube of the heat exchanger 10. The temperature of the gas transferred from 45 to nozzle 102 via transfer line 120 can be maintained relatively close to its transition temperature.

In addition, by providing a vacuum in the vacuum application assembly 125 and the nozzle housing 135, no condensate, moisture or other impurities are formed on the transfer line 120 and / or the nozzle 102. Formation of condensate on transfer line 120 and / or nozzle 102 may interfere with the production of aerosols and may also lead to unstable aerosol jets. When the condensate is formed after the transfer line 120 and the nozzle 102 are cooled, the condensation process generates heat to raise the temperature. This rise in temperature may prevent the gas from being maintained at the desired temperature, and thus no aerosol may be formed. Thus, the process state may become unstable and / or the process time from the standby temperature to the operating temperature may become long or impossible to achieve the operating temperature.

As shown more specifically in FIGS. 6-7, the nozzle 102 has an upper distribution manifold 140 and a lower distribution manifold 145. These manifolds 140 and 145 have dimensions suitable for a particular application, for example, when cleaning an 8 inch wafer, the upper distribution manifold 140 may have a length L1 of about 8.125 inches and a lower side. Dispensing manifold 145 may have a length L2 of about 8.610 inches.

The material selected to form the manifolds 140 and 145 must be able to withstand EROSION due to the pressure of the gas passing through the manifold and also be able to withstand low operating temperatures without breaking. Other factors to consider in selecting a material include ease of processing or manufacturability and cost. Materials that may be used include ceramics, glass, stainless steel, copper, aluminum, plastics, alloys and the like.

The interface 155 between the upper distribution manifold 140 and the lower distribution manifold 145 is provided with a plurality of balancing openings or holes 152, 153, which are manifolds. Do not generate low pressure points in the chamber. These balancing holes 152 and 150 perform a uniform distribution of the gas so that the pressure of the gas passing from the upper distribution manifold 140 to the lower distribution manifold 145 is equalized. If a low pressure point occurs, a change in gas pressure will cause the transition temperature of the gas to change, so a non-uniform aerosol may be generated downstream of the nozzle 102. In addition, non-uniform pressure distribution in the nozzle may cause liquefaction and / or solidification of the gas inside the nozzle and thus may lead to unstable aerosol jets. To avoid the occurrence of such low pressure points in the manifold with the specified length described above, if about six balance holes 150, 152 in a row are evenly spaced at a distance of about 1.333 inches from the center of the adjacent balance holes 150, 152, It has been found that the occurrence of low pressure points can be prevented. Since the gas delivered into the nozzle 102 is oriented towards the balancing hole 150, these balancing holes 150 are larger than those realized in the balancing hole 152 located closest to the distal end of the connection 155. It should be noted that pressure will be realized. Thus, the balancing hole 150 for realizing a higher gas pressure is made smaller than the balancing hole 152 for realizing a lower gas pressure. For example, the flattening holes 152 and 152 may each have a diameter of 0.1 inch to 0.25 inch. In one embodiment, the balancing holes 150 each have a diameter of about 0.125 inches and the balancing holes 152 each have a diameter of about 0.1875 inches.

To increase efficiency, the distribution manifolds 140 and 145 of the nozzle 102 include thin walls, ie walls having a small cross section, for example about 0.030 inches to about 0.05 inches. In this regard, the thin wall allows the distribution manifolds 140, 145 to cool rapidly to the desired operating temperature. This minimizes the cycle time of the nozzle 102 going from standby temperature to processing temperature and also minimizes cooling loss of the gas prior to expansion.

The lower wall 160 of the lower distribution manifold 145 is inclined, which lower row 160 forms a row of exit openings that form aerosols and orient them towards the surface 20 to be cleaned ( 165). This exit can be any detective, for example a round hole or slits. The inclination of the lower wall 160 allows efficient cleaning of the surface 20 by orienting the aerosol in an inclined manner relative to the surface. In this regard, the aerosol jet generated from the outlet 165 is oriented at an angle of 0-90 degrees with respect to the surface 20, preferably at an angle of 45 degrees. Moreover, the outlets 165 should be spaced apart from one another, and this outlet 165 may also be formed as a solid curtain at a predetermined distance from the surface 20 as the gas exits through the outlet 165. It should be sized to allow gas overlap. This allows the entire surface 20 to be covered by the aerosol and cleaned. In addition, the diameter of the outlet 165 must be small enough so that the material can expand sufficiently to a pressure low enough that at least a substantial portion of the material can solidify due to Joule-Thomson cooling of the material to produce an aerosol. In this regard, the diameter of the outlet 165 is a function of the pressure of the material being conveyed to the nozzle 102. The higher the pressure of the conveyed material, the larger the allowable outlet 165 is, and vice versa. For example, when argon gas is being delivered at a pressure of about 70 psig, each outlet 165 may be a hole having a diameter of about 0.005 inches to about 0.1 inches. Moreover, these outlets 165 may be spaced about 0.0625 inches from the center of the next adjacent outlet 165, so that about 128 outlets 165 in the lower distribution manifold 145 having a length of approximately 8.610 inches. Can be deployed.

In this embodiment, the nozzle 102 has mounting segments 170 and 175 that are used to mount the nozzle 102 to the nozzle housing 135 of the chamber cover 130. These mounting segments 170 and 175 may be attached or secured to the nozzle housing 135 by conventional means, such as welding. As shown in FIG. 5, to minimize thermal conduction, the nozzle 102 It is to be noted that the silver is supported within the nozzle housing 135 by simply attaching the mounting segments 170 and 175 to the nozzle housing 135, and the main surface of the nozzle 102 is surrounded by a vacuum. In addition, to further minimize thermal conductivity, the connections 180, 185 between the nozzles 102 and portions of the mounting segments 170, 175 attached to the nozzle housing 135 may be thinned to minimize the cross-sectional area of the connections 180, 185. have. Thus, the connections 180, 185 serve as thermal barriers between the nozzle 102 and the nozzle housing 135. For example, connectors 180 and 185 may be thinned to a thickness of about 0.005 inches.

In another embodiment, as shown in FIGS. 8 to 11, a nozzle apparatus having a nozzle 202 includes a nozzle 202 having a nozzle-mounted enclosure, a housing or a chamber 205. Mounted to extend or suspend in a maneuverable or movable manner therefrom. This nozzle mounting chamber 205 may then be mounted to the tool chamber 210, or any processing equipment or part thereof, that needs to be cleaned. The nozzle 202 is then oriented towards the tool chamber 210, for example, to clean the inner wall of the tool chamber 210 with the aerosol generated from the nozzle 202. Since the nozzle 202 of this embodiment is not attached to the housing as in the above-described embodiment, this nozzle 202 does not require a mounting segment and also between the nozzle 202 and a supporting structure. Note that there is no connection. Thus, in this embodiment, no thermal barriers such as the thin connections 180 and 185 described above are required.

At least sidewall 215 of nozzle-mounted chamber 205 includes a clear material, such as a clear plastic, to allow a user to see the interior of tool chamber 210 being cleaned. In addition, it is preferable to allow the user to observe the nozzle device in the nozzle mounting chamber 205. Sidewall 215 is located between cover 225 and a flange 230, which cover and flange extend through, for example, nozzle mounting chamber 205 and cover 225 and flange ( It is held together using four steel rods 235 attached to 230.

Flange 230 may be temporarily detachably mounted to tool chamber 210 by conventional means, such as bolt 212. In a particular embodiment, the device of the present invention is mounted on an inner wall of an AME5000 plasma tool chamber manufactured by Applied Materials, Inc., Santa Clara, CA, to efficiently clean the inner wall. Found that it can.

The nozzle-mounted chamber 205 further includes a purge port 240 and an exit port 245. This purge port 240 has a purge gas source 242 connected thereto. This purge gas is introduced into the nozzle-mounted chamber 205, which includes the nozzle-mounted chamber 205, the cover 225, the flange 230, the inner surface of the tool chamber 210, or the surface to be cleaned, including the members. Prevents condensate or impurities from forming on the surface of the components included therein. For example, the purge gas should have a purity of at least about 99%, for example the purge gas may comprise dry nitrogen gas. The outlet port 245 is connected with an exhaust and / or vacuum pump 247. The purge gas source and the exhaust / vacuum pump are arranged such that contaminants or particles cleaned from the surface of the tool chamber 210 can be removed through the outlet port 245 to prevent recontamination of the tool chamber 210. do. For example, arranging a purge gas source and an exhaust / vacuum pump to set positive pressure in the chambers 205 and 210 is a technique for accomplishing this task.

Pressure controller 249 may be added on the cleaning line and / or on the exhaust / vacuum pump. This pressure regulator 249 allows the pressure in the nozzle-mounted chamber 205 to be regulated, and the pressure in the nozzle-mounted chamber can remain constant regardless of whether or not the aerosol is being produced. The pressure controller 249 may be connected to the purge gas supply side and / or the exhaust / vacuum pump side according to a pressure balance desigbn, which is shown here as being connected to the exhaust / vacuum pump side. . In addition, a gauge 250 may be included to monitor the pressure within the nozzle-mounted chamber 205.

A gas and / or / liquid supply used to generate the aerosol is sent to an inlet 255 for delivery to a supply line 260 in the nozzle mounting chamber 205. ). As mentioned above, the particular material transferred and its type, i.e. gas, liquid or gas / liquid, depend on the surface and purity requirements of the object being cleaned. In general, other factors to consider in selecting a material include surface damage caused by the material, the type of particles to be cleaned, the work environment, the usefulness of the material, and environmental hazards caused by the material. have. For example, carbon dioxide liquids have been found to be effective for cleaning tool chambers. In this regard, carbon dioxide aerosols are good for removing deposits of an organic nature.

According to the above-described details, the inlet 255 should be connected with the tube 45 of the heat exchanger 10 if cooling is necessary before expansion by the nozzle 202, ie when generating aerosol from gas. However, where low temperature liquids or gases / liquids are used and such cooling is not required, inlet 255 may be directly connected with a supply of liquids or gases / liquids.

In order to produce an aerosol for cleaning the interior of the tool chamber 210, the material is transferred to the nozzle 202 via the supply line 260. One end of the supply line 260 is attached to the cover 225, and the other end of the supply line 260 is connected to the nozzle by conventional means such as a stainless steel collar 263 or by welding. 202 is associated with. Thus, the nozzle 202 is suspended by the supply line 260. The length of the supply line 260 depends on the dimensions of the tool chamber 210 to be cleaned and the area of the tool chamber 2210 that needs to approach the aerosol. In this regard, supply line 260 may have a length such that nozzle 202 may extend beyond flange 230 as shown, or supply line 260 may have nozzle 202 mounted with a nozzle. It may be shortened to be located in the chamber 205.

The nozzle 202 of this embodiment may have a protective coating 265 thereon or may have only one exit opening 270. The protective coating 265 prevents damage that may occur on the inner surface of the tool chamber 210 by accidental contact with the nozzle 202 and all materials suitable for that purpose, such as Teflon (poly) The DuPont Company's name for tetrafluoroethylene).

Although the outlet 270 is shown in the figure as being located at the end of the nozzle 202, the outlet 270 may be located anywhere on the nozzle 202 which may be convenient for orienting the cleaning aerosol. For example, the outlet 270 may be located on one side of the nozzle 202. Moreover, although only one outlet 270 is shown in the figures, it is possible to provide as many outlets 270 arranged in any pattern on the nozzle 202 as necessary for sufficient cleaning. The quantity of outlets 270 to be included depends on the surface area of the surface to be cleaned. It has been found that a single circular opening of the tip of the nozzle 202 with a diameter of about 0.02 inches can produce an aerosol that is efficient for cleaning certain tool chambers. Examples of arrangement of various outlets 270 of nozzles 202 are shown in FIGS. 12A-C. In this regard, the nozzle 202 can be made detachable and interchangeable to suit many cleaning requirements.

If a relatively large number of outlets 270 are required, then the upper and lower distribution manifold arrangements as described above may need to be implemented as the problem of low pressure points may occur. Of course, there is no problem of pressure balance when using only one outlet 270. In addition, as discussed above, the dimensions of the outlet 270 will depend on the transport pressure of the material, but should be small enough to allow adequate expansion for the production of aerosols. Accordingly, the nozzle 202 is made to be detachable conveniently by mounting with conventional screws, pins, clamps, and the like, so that replacement nozzles having variously positioned openings can be used interchangeably.

In order for the aerosol to be able to access and clean all contaminated surfaces of the tool chamber 210, means must be provided for manipulating or manipulating the nozzle 202 to orient the aerosol to such contaminated surfaces. In this regard, supply line 260 may include materials that remain sufficiently flexible during cleaning at the required low temperatures. The supply line 260 may be steered to orient the nozzle 202 towards the surface of the object to be cleaned. For example, plastic and certain metal structures may be used in the structure of the supply line 260 to achieve the required flexibility. As a specific example, it has been found that stainless steel braided tubing with an outer diameter of about 0.125 inch maintains sufficient flexibility to produce aerosol from carbon dioxide liquid delivered at room temperature and at a pressure of about 800 psig. It was.

Other means for providing maneuverability include, for example, a swivel-type joint connecting the supply line 260 with the cover 225. This supply line 260 may be pivoted in a swivel joint 264 to orient the nozzle 202 towards the surface to be cleaned.

In order to control the steering, a conventional automatic steering means such as a robotic arm may be provided, or a manual steering means may be provided. As shown, for manual maneuvering, the housing 205 may have an access opening 275, for example one or more gloves 222 via this access opening 275. It may be entered into the nozzle mounting chamber 205. This access opening 275 may have a frame 280 made of, for example, stainless steel, which accommodates the glove 222 and maintains the nozzle mounting chamber 205 with proper sealing from the atmosphere. I am suitable to do it. The user's hand is inserted into the glove 222 to manually manipulate the nozzle 202. Moreover, a nozzle grip 220 for use as a handle at a predetermined position in front of the nozzle 202 along the supply line 260 for easier and / or more convenient handling. May be provided. This nozzle gripping portion 220 may comprise, for example, Teflon (the commercial name of The DuPont Company for Polytetrafluoroethylene). For more convenience and safety, a valve 223 may be provided along the supply line 260 to control or regulate the transfer of material to the nozzle 202.

13 and 14, in another embodiment of the present invention, the flange 300 is adapted to be mounted directly to the tool chamber 305 to clean the tool chamber 305. The flange 300 is typically mounted to the tool chamber 305 as described above and can also be made permanently mounted or temporarily mounted during cleaning. As shown, the flange 300 has a purging port 310 to which the flue gas supply unit 315 is connected, and an outlet port 320 to which an exhaust and / or vacuum pump 325 is connected; and a pressure regulator 326. Is connected to the exhaust / vacuum pump line. Moreover, the nozzle 330 is mounted to the flange 300. The nozzle 330 is movable / steerably mounted or fixedly mounted, and the supply is directly connected to the inlet 335 of the nozzle 330. As described above, a swivel joint 340 may be provided to connect the nozzle 330 to the flange 300, and an access opening in the flange 300 to allow steering of the nozzle 330. opening 345 may be provided. Also. The purge gas supply and exhaust / vacuum means provides a positive pressure in the tool chamber 305, prevents condensate or moisture or impurities from forming inside the tool chamber 305, and also prevents recontamination of the tool chamber 305. prevent.

Although the present invention has been described in connection with specific embodiments, it will be apparent to those skilled in the art that modifications, changes and variations may be made in light of the above description. Accordingly, the invention is intended to embrace all such modifications, changes and variations that fall within the scope and spirit of the invention and the appended claims.

Claims (25)

Apparatus for mounting a tool having a surface to be cleaned, as well as for generating the surface aerosol from a substance, comprising: mounting a tool having a surface to be cleaned A flange for; A second lower than the first pressure from a first pressure to mount at the flange to receive the material and to solidify at least a substantial portion of the material to produce the surface cleaning aerosol A nozzle having at least one exit opening to allow passage of the material so as to expand at a second pressure; Condensation preventing means for preventing condensation from forming on the surface of the device and the surface of the cleaning object; And contamination preventing means for preventing contaminants from recontaminating the surface after removal of contaminants from the surface. The apparatus of claim 1, wherein the anti-condensation means and the anti-contamination means set a positive pressure in the tool to be cleaned. The apparatus of claim 1 wherein said anti-condensation means comprises purge means. 4. The apparatus of claim 3 wherein said purifying means comprises a purge port and a purge gas source. 5. The apparatus of claim 4, wherein the purge gas source comprises a nitrogen gas source. The apparatus of claim 1 wherein said contamination prevention means comprises an exit port and a pump. The apparatus of claim 1 further comprising a pressure regulator for regulating the pressure in the tool to be cleaned. 2. The apparatus of claim 1 further comprising maneuvering means associated with the nozzle to allow steering of the nozzle. 9. The apparatus of claim 8, wherein the steering means comprises a flexible supply line connected to transfer the material to the nozzle. The apparatus of claim 8, wherein the steering means comprises a swivel-type joint. 9. An apparatus according to claim 8, wherein said steering means has an access opening in said flange. 12. The apparatus of claim 11 further comprising at least one glove introduced through the access opening and adapted to allow a user's hand to control the steering means. The apparatus of claim 1, further comprising an enclosure located between a cover and the flange. 14. The apparatus of claim 13, wherein the anti-condensation means and the anti-contamination means are within the seal and of the cleaning object; Device for setting static pressure in the tool. The apparatus of claim 13, wherein the closure comprises a clear material. The apparatus of claim 13, wherein the closure has maneuvering means for manipulating the nozzle. 17. The apparatus of claim 16, wherein the steering means has a flexible supply line disposed in the enclosure, the flexible supply line having one end adapted to receive the material, Device with the other end being mounted. 18. The apparatus of claim 17, further comprising a valve in the flexible supply line to control the transfer of material to the nozzle. 17. The apparatus of claim 16 wherein the steering means comprises a swivel-type joint. 17. The apparatus of claim 16 wherein the steering means includes an access opening in the closure. 21. The apparatus of claim 20, further comprising at least one glove introduced into the enclosure through the access opening and adapted to allow a user's hand to control the steering means. Device. The apparatus of claim 13, wherein the nozzle is disposed within the enclosure. The apparatus of claim 13, wherein the nozzle extends past the flange to be inserted into the tool to be cleaned. 14. The apparatus of claim 13, wherein the cover has a purge port and an exit port. The apparatus of claim 1, wherein the nozzle is replaceable.