Abstract:
A plurality of nozzles and treating liquid supplying tubes are supported by rigid support arms forming part of temperature control piping for contacting the tubes to maintain treating liquids in the tubes to a constant temperature. The support arms are pivotable about a pivot axis located sideways from a substrate, such that the nozzles are movable between a dispensing position and a standby position displaced from above the substrate. A drive arm engages and swings a selected one of the support arms to move the nozzle attached to the selected support arm, between the dispensing position and standby position. With this construction, a nozzle selected from the plurality of nozzles is reliably moved in a predetermined posture to a predetermined position, while allowing sufficient temperature control of treating liquids by the temperature controlling piping, and avoiding inadvertent dripping of the treating liquids due to deformations of the treating liquid supplying tubes.

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates to a treating liquid supplying apparatus for a substrate spin treating apparatus for supplying photoresist or other surface treating liquids to substrates, such as semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays or substrates for optical disks, to effect a surface treatment thereof. Specifically, such a treating liquid supplying apparatus has a plurality of nozzles for supplying the treating liquids to a substrate supported for a spinning motion, a plurality of tubes for connecting the nozzles to treating liquid storages, temperature control piping for contacting the tubes to maintain the treating liquids therein at a constant temperature, and a nozzle moving device for moving a selected one of the nozzles to a dispensing position above the substrate under treatment. 
     (2) Description of the Related Art 
     With this type of spin treating apparatus, it is desired that a plurality of treating liquid supplying systems be provided for one such apparatus in order selectively to supply plural types of treating liquids having different components or different degrees of viscosity. For this purpose, a known apparatus, as disclosed in Japanese Utility Model Publication No. 4-52990, for example, includes a transfer arm for gripping and moving a selected one of a plurality of nozzles arranged in a standby position to a dispensing position above a substrate. 
     The known apparatus, however, has the following drawbacks: 
     (1) When the transfer arm grips and moves one of the nozzles, the hardness of a tube connected to this nozzle imparts a resistance to vary a nozzle posture. Such a resistance places the nozzle in an unsteady dispensing posture upon arrival at the dispensing position above the substrate, e.g. displaced from the predetermined dispensing position, or tilted instead of facing directly downward. As a result, the nozzle applies the treating liquid to inappropriate regions of the substrate. Generally, precision in the order of 0.1 mm is required for positions of the substrate to which the treating liquid is applied, in order to effect a uniform treatment. Such misapplication of the treating liquid results in a low quality treatment. 
     (2) The tube connecting each nozzle to its treating liquid source is displaced to a large extent when the nozzle is moved between standby position and dispensing position. Consequently, where the treating liquid supplying tube extends through temperature control piping for maintaining the treating liquid at a constant temperature, it is difficult to make a piping arrangement because of the rigidity of such a multiple pipe structure. 
     Conversely, where such temperature control piping is formed of a thin, flexible material to give priority to the piping arrangement, a temperature controlling fluid may flow through the pipes only in an insufficient quantity. Then, the treating liquid supplying tubes cannot receive a uniform temperature control peripherally thereof, which results in a reduced precision of temperature control. 
     (3) The tube is subjected to a considerable bending and twisting deformation, resulting in volume variations within the pipe. With such volume variations, the treating liquid tends to fall in large drops from the nozzle to the substrate. 
     SUMMARY OF THE INVENTION 
     A primary object of the present invention is to provide a treating liquid supplying apparatus for reliably moving a selected one of a plurality of nozzles in a predetermined posture to a predetermined position, while allowing sufficient temperature control of treating liquids by means of temperature control piping, and avoiding inadvertent dripping of the treating liquids due to deformations of treating liquid supplying tubes. 
     It is also an object of the invention to move a selected one of the nozzles without entailing impurities or particles of dust to substrates. 
     Other objects of the invention will be apparent from the preferred embodiments described hereinafter. 
     The above objects are fulfilled, according to the present invention, by a treating liquid supplying apparatus for a substrate spin treating apparatus comprising a plurality of nozzles each for supplying a treating liquid to a substrate supported for a spinning motion; a plurality of tubes for connecting the nozzles to respective treating liquid storages, otherwise known as supplies or reservoirs; temperature control piping for contacting the tubes to maintain the treating liquids in the tubes to a constant temperature; and a nozzle moving device for selecting and moving one of the nozzles to a dispensing position above the substrate; wherein sets of one nozzle and one tube each are supported by rigid support arms, respectively; the nozzle moving device including an arm support device for supporting each of the support arms to be pivotable about a pivot axis displaced from above the nozzles, such that a selected one of the nozzles is movable between the dispensing position and a standby position displaced from above the substrate; and an arm swing device for selectively engaging and swinging the support arms to move the selected nozzle between the dispensing position and the standby position. 
     In the treating liquid supplying apparatus according to the present invention, each set of one nozzle and one tube is supported by an individual rigid support arm, and the arm swing device is operated to engage the support arm supporting a desired set of nozzle and tube. When the arm swing device causes the support arm to pivot about the pivot axis established by the arm support device, the desired nozzle supported by the above support arm moves to a predetermined position. 
     Thus, the movement of the nozzle is controlled to be a pivotal movement about the pivotal axis established by the arm support device, with a distance of the nozzle from the pivot axis established by the support arm. As a result, a selected nozzle may be moved accurately to a predetermined position through a pivotal movement having a fixed center and radius. 
     Since this support arm supports a tube as well as a nozzle, forces resulting from any deformation of the tube during the movement are received by the support arm, without being applied to the nozzle. Consequently, there arises no possibility of the nozzle being subjected to an unsteady posture or deviating from a treating liquid dripping position. 
     As noted above, each set of one nozzle and one tube is supported by a support arm, and the arm swing device is operated to engage the support arm supporting a desired set of nozzle and tube. The desired nozzle is moved to the predetermined position through a pivotal movement about the pivot axis established by the arm support device. Thus, the movement of the nozzle is a controlled movement having a fixed center and radius, which assures an accurate transfer of the nozzle to the predetermined position. Further, since the support arm supports a tube as well as a nozzle, forces resulting from any deformation of the tube during the movement are received by the support arm, without being applied to the nozzle. This enables the nozzle to move to the predetermined dispensing position reliably in a predetermined posture, to enhance treating precision. 
     Moreover, the feature that a selected support arm is swung about a predetermined pivot axis imposes little restriction to the piping arrangement. The treating liquid supplying tubes and the temperature control piping for contacting the tubes may have thicknesses as desired and may be formed of a wide variety of materials, thereby to effect excellent temperature control for the treating liquids. 
     The deformation of the tubes resulting from pivotal movement of the support arms is limited to a twisting deformation about the pivot axis. Compared with the prior construction in which the tubes undergo both bending and twisting deformations, less volume variations take place inside the tubes according to the present invention. This is effective to avoid inadvertent dripping of the treating liquids due to such deformation of the treating liquid supplying tubes. 
     In another aspect of the invention, the foregoing objects are fulfilled by a treating liquid supplying apparatus for a substrate spin treating apparatus comprising a plurality of nozzles each for supplying a treating liquid to a substrate supported for a spinning motion; a plurality of tubes for connecting the nozzles to treating liquid storages, respectively; temperature control piping for contacting the tubes to maintain the treating liquids in the tubes to a constant temperature; and a nozzle moving device for selecting and moving one of the nozzles to a dispensing position above the substrate; wherein sets of one nozzle and one tube each are supported by rigid support arms, respectively; the nozzle moving device including arm swing supports for pivotally supporting the support arms, respectively; an arm selecting and moving device for moving a selected one of the arm swing supports to a predetermined position located sideways from the substrate; an aligning and engaging device for engaging the selected support arm moved to the predetermined position by the arm selecting and moving device, to render the selected support arm pivotable about a pivot axis displaced from above the nozzles; and an arm swing device for engaging and swinging the selected support arm aligned by the aligning and engaging device, to move the nozzle supported by the selected support arm between the dispensing position and a standby position displaced from above the substrate. 
     According to this treating liquid supplying apparatus, each set of one nozzle and one tube is supported by a support arm, and the arm selecting and moving device is operable to move the support arm supporting a desired set of nozzle and tube to a predetermined position located sideways from the substrate. After the aligning and engaging device establishes a pivot axis, the arm swing device is placed in engagement with this support arm. Then the arm swing device is operated to swing the support arm about the pivot axis established by the aligning and engaging device. As a result, the nozzle supported by this support arm moves to a predetermined position. 
     Thus, the movement of the nozzle is controlled to be a pivotal movement about the pivotal axis established by the aligning and engaging device, with a distance of the nozzle from the pivot axis established by the support arm. As a result, a selected nozzle may be moved accurately to a predetermined position through a pivotal movement having a fixed center and radius. 
     Since this support arm supports a tube as well as a nozzle, forces resulting from any deformation of the tube during the movement are received by the support arm, without being applied to the nozzle. Consequently, there arises no possibility of the nozzle being subjected to an unsteady posture or deviating from a treating liquid dripping position. 
     As in the preceding treating liquid supplying apparatus according to the present invention, the nozzle may be moved to the predetermined dispensing position reliably in a predetermined posture to enhance treating precision. In the second aspect of the invention, excellent temperature control may also be effected for the treating liquids, while avoiding inadvertent dripping of the treating liquids due to deformation of the treating liquid supplying tubes. 
     In addition, the arm swing device engages a selected support arm in the position located sideways from the substrate, i.e. displaced from above the substrate, and swings the support arm between the dispensing position and standby position. As a result, the nozzle is moved without entailing impurities or particles of dust to the substrate. This assures a still higher level treating quality. 
     In a further aspect of the invention, the foregoing objects are fulfilled by a treating liquid supplying apparatus for a substrate spin treating apparatus comprising a plurality of nozzles each for supplying a treating liquid to a substrate supported for a spinning motion; a plurality of tubes for connecting the nozzles to treating liquid storages, respectively; temperature control piping for contacting the tube to maintain the treating liquids in the tubes to a constant temperature; and a nozzle moving device for selecting and moving one of the nozzles to a dispensing position above the substrate; wherein sets of one nozzle and one tube each are supported by rigid support arms, respectively; the nozzle moving device including arm swing supports for supporting the support arms to be pivotable about different predetermined pivot axes located sideways from the substrates, respectively; an arm selecting device movable from one of the support arms to another to engage a selected support arm; and an arm swing device for swinging the selected support arm engaged by the arm selecting device in a position displaced sideways from the substrate, to move the nozzle supported by the selected support arm between the dispensing position and a standby position displaced from above the substrate. 
     According to this treating liquid supplying apparatus, each set of one nozzle and one tube is supported by a support arm, and a plurality of such support arms are in turn supported by the arm swing supports to be pivotable about different pivot axes located sideways from the substrate, respectively. The arm selecting device is operable to engage the support arm supporting a desired set of nozzle and tube and to swing this support arm about the pivot axis established by the arm swing support. As a result, the nozzle supported by this support arm moves to a predetermined position. 
     Thus, the movement of the nozzle is controlled to be a pivotal movement about the pivotal axis established by the arm swing support, with a distance of the nozzle from the pivot axis established by the support arm. As a result, a selected nozzle may be moved accurately to a predetermined position through a pivotal movement having a fixed center and radius. 
     Since this support arm supports a tube as well as a nozzle, forces resulting from any deformation of the tube during the movement are received by the support arm, without being applied to the nozzle. Consequently, there arises no possibility of the nozzle being subjected to an unsteady posture or deviating from a treating liquid dripping position. 
     As in the preceding treating liquid supplying apparatus according to the present invention, the nozzle may be moved to the predetermined dispensing position reliably in a predetermined posture to enhance treating precision. In the third aspect of the invention, excellent temperature control may also be effected for the treating liquids, while avoiding inadvertent dripping of the treating liquids due to deformation of the treating liquid supplying tubes. 
     In addition, the arm selecting device engages the selected support arm in the position located sideways from the substrate, i.e. displaced from above the substrate, and swings the support arm between the dispensing position and standby position. As a result, the nozzle is moved without entailing impurities or particles of dust to the substrate. This assures a still higher level treating quality. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For the purpose of illustrating the invention, there are shown in the drawings several forms which are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. 
     FIG. 1 is a side view, partly in section, of a first embodiment of the invention. 
     FIG. 2 is a plan view of the first embodiment. 
     FIG. 3 is a side view, partly in section, of a principal portion of the first embodiment. 
     FIG. 4 is a side view, partly in section, of the first embodiment with a support arm placed in an engaged position. 
     FIG. 5 is a side view, partly in section, of the first embodiment with the support arm placed in a raised position. 
     FIG. 6 is a side view, partly in section, of a second embodiment of the invention. 
     FIG. 7 is a side view, partly in section, of a third embodiment of the invention. 
     FIG. 8 is a plan view of the third embodiment. 
     FIG. 9 is a sectional view of a principal portion of the third embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention will be described hereinafter with reference to the drawings. The first embodiment (FIGS. 1-5) of treating liquid supplying apparatus constructed according to this invention includes a plurality of nozzles 1 each for supplying a photoresist solution, which is one example of treating liquids, to a semiconductor wafer W (FIG. 2) supported for a spinning motion. Each nozzle 1 is connected to a treating liquid storage T through a tube 2 (FIG. 3). The tube 2 is covered by temperature control piping 3 for circulating constant temperature water to maintain the treating liquid in the tube 2 at a constant temperature. The apparatus further includes a nozzle moving mechanism for moving a selected one of the nozzles 1 between a dispensing position adjacent and above the center of spinning of wafer W, and a standby position retracted from above the wafer W. 
     Each nozzle 1 is attached to a distal end of a highly rigid metal pipe 3a acting as part of the temperature control piping 3, with a forward portion of the tube 2 supported in the metal pipe 3a. The metal pipe 3a houses a return tube 5 as well. The constant temperature water supplied to the interior of the metal pipe 3a is recovered through the return tube 5 after heating the treating liquid in the tube 2 to the constant temperature. The constant temperature water may flow in a direction opposite to the above, i.e. may be supplied through the return tube 5 to the interior of the temperature control piping 3. 
     The metal pipe 3a is rigidly attached at a proximal end thereof to a support block 6, and a tubular shaft 7 formed of metal is secured to one end of the support block 6. The metal pipe 3a, support block 6 and tubular shaft 7 constitute a rigid support arm 4 for supporting the nozzle 1 and tube 2. The temperature control piping 3 includes the metal pipe 3a, support block 6, tubular shaft 7 and return tube 5. A constant temperature water supply tube 8 is connected to a lower end of the tubular shaft 7 to form part of the temperature control piping 3. The treating liquid supply tube 2 and return tube 5 extend through the constant temperature water supply tube 8. This water supply tube 8 is connected to a constant temperature water source not shown. 
     The tubular shaft 7 of each support arm 4 is supported by an arm swinging support 9 to be rotatable about the axis of the tubular shaft 7. This and other arm swinging supports 9 are juxtaposed in a direction perpendicular to the plane of FIG. 1 and supported by a common movable frame 10 to be vertically slidable along respective guide rails 11. 
     The movable frame 10 is supported by a stationary frame 12 of the substrate spin treating apparatus to be movable horizontally along a guide rail 13. The movable frame 10 carries a rack 14 meshed with a pinion 16 driven by an electric motor 15 rotatable in both directions. Thus, the arm swinging supports 9 are movable along the direction perpendicular to the plane of FIG. 1 by the electric motor 15 being rotated in both the directions. 
     A lift frame 18 is disposed laterally of the arm swinging supports 9 to be vertically movable by a pair of air cylinders 17a and 17b in series connection. The lift frame 18 includes a movable bracket 20 vertically movable by an air cylinder 19. The movable bracket 20 includes a support shaft 21a mounted in an upper portion thereof to be rotatable about a pivot axis P located in a predetermined position. A drive arm 21 is attached to a lower end of the support shaft 21a to be pivotable about the pivot axis P. 
     The support block 6 of each support arm 4 has a conical engaging recess 22 formed in an upper surface thereof and located on the axis of the tubular shaft 7. The support block 6 also has an engaging pin 23 projecting from a position thereof spaced from the recess 22 toward the nozzle 1. 
     On the other hand, the drive arm 21 has a conical engaging projection 24 formed on a lower surface thereof and located on the pivot axis P, and an engaging bore 25 spaced from the pivot axis P and opposed to the engaging pin 23. A selected one of the support arms 4 is movable by an arm selecting and moving mechanism including the movable frame 10 and electric motor 15, to a predetermined position to place the axis of the tubular shaft 7 directly under the pivot axis P of the drive arm 21. When one of the support arms 4 is moved to this position, the drive arm 21 is lowered to have engaging projection 24 and engaging bore 25 of the drive arm 21 engage with the engaging recess 22 and engaging pin 23 of the support arm 4, respectively. Thus, an engaging and aligning mechanism is provided to position and maintain the drive arm 21 and support arm 4 in a firmly engaged state, with the axis of the tubular shaft 7 aligned to the pivot axis P of the drive arm 21. The construction for engaging the engaging projection 24 and engaging bore 25 of the drive arm 21 with the engaging recess 22 and engaging pin 23 of the support arm 4, respectively, to maintain the drive arm 21 and support arm 4 in the firmly engaged state is called herein an engaging mechanism. 
     The support shaft 21a supporting the drive arm 21 is operatively connected through a timing belt 27 to an electric motor 26 secured to the movable bracket 20 and rotatable in both directions. Thus, an arm swing mechanism is provided to swing, with the electric motor 26 being rotated in both the directions, the support arm 4 engaged with the drive arm 21 as noted above, about the pivot axis P set to the predetermined position. Consequently, the nozzle 1 on this support arm 4 is moved between the standby position displaced sideways or outboard from the wafer W and the dispensing position adjacent the center of the wafer W. 
     An operation of the foregoing construction for supplying the treating liquid will be described next. 
     (1) In an initial state, as shown in solid lines in FIGS. 1 and 2, all the nozzles 1 are retracted to the standby position displaced sideways or outboard from the wafer W, with the arm swinging supports 9 standing by in a lower position (L). Each arm swinging support 9 in the lower position (L) is set to a predetermined posture through engagement between a positioning projection 28 formed on a lower surface of the support block 6 and a positioning recess 29 formed in an upper surface of the movable frame 10. 
     In this standby state, each nozzle 1 is dipped in a wet atmosphere contained in a fixed anti-drying cup 30. 
     (2) For supplying the treating liquid, the electric motor 15 is operated first to drive the movable frame 10, whereby the support arm 4 of a selected nozzle 1 is brought to a position under the pivot axis P or drive arm 21. 
     (3) Next, as shown in FIG. 4 which is a partly sectional side view, the air cylinder 19 is extended to lower the movable bracket 20, thereby lowering the drive arm 21 into engagement with the support arm 4. Consequently, the tubular shaft 7, about which the support arm 4 is pivotable to move the selected nozzle 1 to the dispensing position above the wafer W, is aligned to the pivot axis P of the drive arm 21. 
     (4) Subsequently, the air cylinders 17a and 17b are both extended (FIG. 5) to raise the lift frame 18. In an early stage of this ascent, a contact portion 31 of the lift frame 18 moves up against a lug 32 projecting from an upper end of the arm swinging support 9. As a result, the support arm 4 is vertically clamped between the drive arm 21 and the contact portion 31 of the lift frame 18. In the clamping state, the lift frame 18 is raised further to raise both the support arm 4 and arm swinging support 9 to an upper limit (H) as shown in FIG. 5. 
     (5) Next, the electric motor 26 is rotated forward, causing the drive arm 21 to pivot a predetermined angle clockwise in FIG. 2, thereby to swing the nozzle 1 to the predetermined dispensing position above the wafer W. 
     (6) Then, one of the air cylinders 17a and 17b is contracted to lower the nozzle 1 to a predetermined liquid feeding level (F) over the wafer W. In this state, a predetermined quantity of treating liquid is allowed to drip onto the wafer W prior to a spin or while wafer W has started spinning at low speed. Immediately thereafter, the wafer W is spun at high speed so that the treating liquid may be spread uniformly thereon. 
     (7) Upon completion of the treating liquid supplying step, the contracted air cylinder is extended again to retract the support arm 4 and nozzle 1 up to the predetermined height (H) over the wafer W. Then, the electric motor 26 is rotated backward to swing the support arm 4 back to the standby position. With the support arm 4 now lying in the standby position, both the air cylinders 17a and 17b are contracted to lower the lift frame 18 to its lower limit. The air cylinder 19 also is contracted to raise the movable bracket 20 and drive arm 21, thereby disengaging the drive arm 21 from the support arm 4. For using a different one of nozzles 1, the movable frame 10 is suitably driven to select a corresponding support arm 4 for engagement with the drive arm 21, which is followed by the above sequence of operation. 
     FIG. 6 is a side view showing a treating liquid supplying apparatus for a substrate spin treating apparatus in a second embodiment of the invention. This embodiment differs from the first embodiment as follows. 
     In this embodiment, a connecting arm 40 is attached to a lower end of the tubular shaft 7 of each support arm 4, and this connecting arm 40 is engageable with a drive arm 21 for alignment. The tubular shaft 7 is clamped by the drive arm 21 and a contact element 41 independently driven up and down by an air cylinder 42 mounted on a lift frame 20. The other aspects are the same as in the first embodiments, and like reference numerals are used to identify like parts which will not be described again. 
     FIGS. 7-9 illustrate an embodiment of treating liquid supplying apparatus according to this invention for a substrate spin treating apparatus. This third embodiment differs from the first embodiment in the following aspects. 
     In this embodiment, a plurality of support arms 4 each supporting a nozzle 1 and a tube 2 are juxtaposed to be pivotable about pivot axes Q1, Q2 and Q3 set to different predetermined positions, respectively. Each support arm 4 is connected at a proximal end thereof to a tubular shaft 7 rotatably supported in an arm swinging support 9. The support 9 is supported by an apparatus frame 50 to be vertically movable along a guide rail 51. A drive arm 21 is disposed laterally of these support arms 4 to be pivotable about a predetermined axis R for selecting a nozzle 1 to be used. 
     Each support arm 4 is pivotable about the pivot axis Q1, Q2 or Q3 extending vertically, such that a length from its pivot axis Q1, Q2 or Q3 to the nozzle 1, in plan view, equals a distance between the pivot axis Q1, Q2 or Q3 and the center of wafer W or the treating liquid dispensing position of the nozzle 1. 
     The drive arm 21 is connected at a proximal end thereof to a support shaft 52 supported by a lift frame 18 to be rotatable about the axis R. The lift frame 18 is vertically movable by a pair of air cylinders 17a and 17b in series connection. An arm 53 extending from the support shaft 52 is operatively connected through a linkage 54 to an electric motor 26 mounted on the lift frame 18 and rotatable in both directions. By the electric motor 26 being rotated in both the directions, the drive arm 21 is movable over and traversing the plurality of support arms 4. 
     A V-groove roller 55 is mounted adjacent and above the proximal end of each support arm 4 to be rotatable about a vertical axis. The drive arm 21 has a pair of right and left guide rails 57 mounted on a lower surface thereof to be extendible and retractable longitudinally of the drive arm 21 by an air cylinder 56. The roller 55 is engageable with the guide rails 57 when the latter are extended forward and cooperate therewith to constitute a lost motion driving connection between drive arm 21 and the selected support arm. The other aspects are the same as in the first embodiments, and like reference numerals are used to identify like parts which will not be described again. 
     The third embodiment is operable as follows: 
     (1) The drive arm 21 is swung over the support arms 4 standing by in the lower position (L) to select the support arm 4 of a nozzle 1 to be used. The guide rails 57 are advanced to engage and support the roller 55 of the selected support arm 4. 
     (2) Both of the air cylinders 17a and 17b are extended to raise the lift frame 18 and move the selected support arm 4 to the upper limit (H). 
     (3) Next, the drive arm 21 is swung to move the nozzle 1 on the engaged support arm 4 to the dispensing position over the wafer W. At this time, the difference in the center of pivotal movement between the support arm 4 and drive arm 21 is absorbed by a relative movement between the guide rails 57 and roller 55. 
     (4) Subsequently, one of the air cylinders 17a is contracted to lower the support arm 4 a predetermined amount, thereby to set the support arm 4 to a predetermined liquid feeding height (F) relative to the wafer W. 
     In the first to third embodiments described hereinbefore, each metal pipe 3a forming part of the temperature control piping 3 is used also as part of the support arm 4 for supporting the nozzle 1 and tube 2. Thus, the tube 2 is enclosed in the metal pipe 3a, i.e. in the support arm 4. Instead of this construction, a support arm may be provided separately from the temperature control piping 3 and exclusively for supporting the nozzle 1 and tube 2. 
     The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.