Abstract:
The invention relates to a device for the vaporization of materials with a vaporizer tube or the like, which includes at least one discharge port for the vaporized material. The vaporizer tube is connected with a vapor distributor and comprises at least two separately heatable vaporizer units. In the vaporizer tube are provided an upper and a lower piston, which are separated by a gap. The at least two separate vaporizer units encompass at least the lower and/or the upper piston in the form of tongs.

Description:
TECHNICAL FIELD  
       [0001]     A device for vaporizing materials is described.  
       BACKGROUND  
       [0002]     The electronic device industry can today no longer be imagined without coating processes for the application of layers on substrates as a fabrication technique. The layers applied on these substrates can serve for example as protective layers or only as decorative layers.  
         [0003]     An example of such a coating process is the vaporization process. In a vaporization process materials are introduced into a vaporizer device and subsequently converted to the gaseous phase. These gaseous materials subsequently move in the direction toward a substrate where they are deposited and form a highly uniform layer. It is understood that after such a first layer has been applied, further layers can be applied in this manner such that it is also possible to apply multilayer systems onto a substrate.  
         [0004]     For example, a coating process is known in which a substrate is coated in a vacuum chamber with vaporous organic material (EP 1 401 036 A2). The coating chamber includes several vaporizer sources, disposed one next to the other, which are connected with a vapor outlet provided with nozzles, via which the vapor can migrate in the direction toward the substrate in order to be deposited thereon. Between each vaporizer source and the vapor outlet a valve is provided with which the quantity of the outflowing vapor can be adjusted.  
         [0005]     A vaporizer device for coating a substrate is furthermore known, which includes a coating chamber (US 2005/0241585 A1). This vaporizer device further comprises at least two vaporizer sources disposed separately from one another, which include means with which the quantity of vapor flowing into the coating chamber can be individually controlled.  
         [0006]     A vaporizer device is further known with several vaporizer sources (U.S. Pat. No. 6,770, 562 B2) placed separately next to one another. Above these vaporizer sources is located a coating chamber in which the substrate is disposed. The coating chamber is partitioned into several sections through which the substrate passes successively. Each of these sections is connected to one vaporizer source each, such that the substrate is coated successively by the vapor leaving the vaporizer sources. A valve disposed between the sections and the vaporizer sources serves for controlling the quantity of outflowing vapor.  
       SUMMARY  
       [0007]     In one aspect, a device for vaporizing materials is described. The device includes a vaporizer tube or the like, which includes at least one discharge port for the vaporized material. The vaporizer tube is connected with a vapor distributor and comprises at least two separately heatable vaporizer units. In the vaporizer tube are provided an upper and a lower piston separated by a gap. The at least two separate vaporizer units encompass at least partially the lower and/or the upper piston in the form of tongs.  
         [0008]     One potential advantage is reducing the thermal loading of the material to be vaporized in spite of a long service life of the device for the vaporization of material.  
         [0009]     Another potential advantage is that materials which do not remain thermally stable over a relatively long time period can also be vaporized. The material is for this purpose can be vaporized in small portions. Additional material can be only made available when the previous portion has been vaporized. The material to be vaporized can thereby only be exposed to the vaporization temperature for a short time.  
         [0010]     Another potential advantage is that the adjacent vaporizers can be driven steplessly, whereby the vaporization can run continuously without interruption. 
     
    
     DESCRIPTION OF DRAWINGS  
       [0011]      FIG. 1 a  segment of a device for vaporizing material with a vaporizer tube located outside of the vacuum chamber,  
         [0012]      FIG. 2 a  segment of the vaporizer tube depicted in  FIG. 1  according to section along B-B and C-C through this vaporizer tube,  
         [0013]      FIG. 3 a  perspective view of a vaporizer unit,  
         [0014]      FIG. 4 a  top view onto the segment of the vaporizer tube depicted in  FIG. 2 ,  
         [0015]      FIG. 5 a  section through the segment of the vaporizer tube depicted in  FIG. 2  along D-D,  
         [0016]      FIG. 6 a  partial segment of the vaporizer tube depicted in  FIG. 5  after the section has also been carried out through the vaporizer units. 
     
    
     DETAILED DESCRIPTION  
       [0017]      FIG. 1  depicts a segment of a device  1  for the vaporization of material with a vaporizer tube  3  located outside a vacuum chamber  2 . This vaporizer tube  3  is connected via a connection tube  4  with a distributor  5  disposed within the vacuum chamber  2 . For the sake of clarity, only a segment of the vacuum chamber  2  with the vacuum chamber wall  6  is shown, the vacuum chamber  2  being structured, for example, corresponding to the vacuum chamber described in DE 101 28 091 C1.  
         [0018]     In order for a pressure to be maintained once it is established in the vacuum chamber  2 , the vacuum chamber wall  6  completely encompasses the connection tube  4 . However, it is also possible that, as also depicted in  FIG. 1 , sealing material  7  is additionally applied around the connection tube  4 . Thereby the pressure obtained in the vacuum chamber  2  can be maintained. The sealing material  7  includes, for example, a rubber-type elastic material impermeable to gas.  
         [0019]     The vaporizer tube  3  is sealed off at both ends  8 ,  9  with closures  10 ,  11 , for example with caps  10 ,  11 . These caps  10 ,  11  preferably include at least one connection. Thus cap  11 , as shown in  FIG. 1 , includes two connections  12 ,  13 . To one of these connections  12 , for example, a heater can be connected which, however, is not shown here. With this heater the material in the vaporizer tube can be vaporized. To the other connection  13  can be attached a temperature sensor, with which the temperature conditions occurring in the vaporizer tube  3  can be monitored. The temperature sensor is, however, not shown here.  
         [0020]     Slots can be provided in the vaporizer tube  3  for the connections of the heating and the cooling systems of the vaporizer units. The connections at the vaporizer units can be effected as rigid connections, and the external supply lines can be effected as flexible.  
         [0021]     The cap  10  also includes several connections  14 ,  15 . Via the connection  14 , the vaporizer tube  3  is connected with a control. At the connection  15  a vacuum pump may be attached with which a vacuum can be generated in the vaporizer tube  3  such that, before the vaporization process, a pressure can be obtained which corresponds to that in the vacuum chamber  2 . A vacuum pump, however, is not shown for the sake of clarity.  
         [0022]     The vaporizer tube  3  may also include several connections. Thus, in  FIG. 1  two connections  16 ,  17  are evident which are disposed directly on the vaporizer tube  3 . These connections  16 ,  17  serve the purpose of providing the vaporizer tube  3  with a coolant, for example water, when needed. The connection  16  serves herein for example as coolant outlet and connection  17  as coolant inlet.  
         [0023]     Like the vaporizer tube  3 , the distributor  5  is also closed at its two ends  18 ,  19 . This can be accomplished for example with closures  20 ,  21 , for example caps  20 ,  21 . These caps  20 ,  21  can also be provided with connections, only two connections  22 ,  23  being shown in  FIG. 1 , which are disposed on cap  20 . Via these connections  22 ,  23  the distributor  5  can, for example, be connected with a heater, such that in the distributor  5  a temperature is obtained, for example, which corresponds to the temperature obtained in the vaporizer tube  3 . However, the connections  22 ,  23  may also be utilized for the coolant supply or for applying a temperature sensor. Heater, temperature sensor or coolant supply are not shown in  FIG. 1 .  
         [0024]     The distributor  5  includes at least one opening, preferably several openings disposed in a row, which, however, are not evident in  FIG. 1 . Through these openings the vapor reaches the substrate  24  located in the vacuum chamber  2 . This substrate  24  is moved past the at least one opening of the distributor, such that the vapor moves toward the substrate  24  and is here deposited. The substrate shown in  FIG. 1  is therein moved into or also out of the plane of drawing. Such a movement of the substrate past the distributor is described for example in DE 101 28 091 C1, the disclosure of which is incorporated by reference.  
         [0025]      FIG. 2  shows a segment of the vaporizer tube  3  depicted in  FIG. 1  after section through this vaporizer tube  3  along B-B and C-C. In the interior of the vaporizer tube  3  with its wall  25  is disposed a cylinder  26  which is directly in contact on the wall  25 . A vaporizer unit  27  in the form of a ring is disposed on the cylinder  26 , and between this vaporizer unit  27  and the cylinder  26  is located an insulating layer  28 . The vaporizer unit  27 , the cylinder  26  as well as the insulating layer  28  are open in a region  29  in the direction toward the connection tube  4 .  
         [0026]     Through the vaporizer unit  27 , as well as the region  29  open in the direction toward the connection tube  4 , extends an inner piston, which is divided into an upper and a lower piston. Only the upper piston  30  is evident in  FIG. 2 . In contrast to the upper piston  30 , cylinder  26  with the insulating layer  28  as well as the vaporizer unit  27  are not fixedly disposed in the vaporizer tube  3 , but are movable along a guide rod  31 . The movement is therein controlled via the control connected to the connection  14  ( FIG. 1 ).  
         [0027]     Since the vaporizer unit  27  is disposed directly on the upper piston  30 , the upper piston  30  also serves as a guide element. The disposition comprised of vaporizer unit  27 , cylinder  26  as well as insulating layer  28  can consequently be moved along the upper piston  30 .  
         [0028]      FIG. 3  shows a perspective view of a vaporizer unit  32 , which corresponds to the vaporizer unit  27 , without showing the insulating layer  28  encompassing it and without the cylinder  26 . The vaporizer unit  32 , which has the form of a ring open toward one side, includes on the outside  33  an indentation  34 , in which an encircling heater  35  is disposed. This heater  35  may be for example a heating filament.  
         [0029]     However, it is also conceivable that a heating filament is disposed in the interior of the vaporizer unit  32  and that a cooling system is located in the indentation  34 . As the cooling means can serve water, which, it is understood, must be removed during heating operation. The vaporizer unit includes at its internal side  36  a tub  37  for receiving the material  38  to be vaporized and with which the substrate is to be coated. The vaporizer unit  32  further comprises at its top side  39  three openings  40 ,  41 ,  42 . Since the vaporizer unit  32  is preferably comprised of a material which has good thermal conductivity, via the heater  35  consequently the entire vaporizer unit  32  is brought to a temperature at which the material  38  to be vaporized is converted into the gaseous state.  
         [0030]      FIG. 4  depicts a top view onto the segment shown in  FIG. 2  of the vaporizer tube  3 . Evident are the wall  25  of the vaporizer tube  3  as well as the cylinder  26  disposed thereon with the insulating layer  28  and the vaporizer unit  27 . The vaporizer unit  27  includes on its top side  39  several openings  40  to  42 . These openings  40  to  42  serve for fixing the insulating layer  50 ,  71  to  79  of the vaporizer units on one another by means of rods. These vaporizer units could become turned out of position as soon as they are in operation and the pistons  30 ,  80  are not available as guides.  
         [0031]     Evident is also the tub  37  of vaporizer unit  27 , in which is located the material  38  to be vaporized. The vaporizer unit, open in the direction toward region  29 , encompasses the upper piston  30 . Along the guide rod  31  it is possible to move the vaporizer unit  27  disposed on cylinder  26  with the insulating layer  28  along the upper piston  30 . The upper piston  30  consequently serves as a guide element.  
         [0032]      FIG. 5  shows a section through the segment depicted in  FIG. 2 , of the vaporizer tube  3  along D-D, the section only being completed through wall  25 , cylinder  26  as well as the insulating layer  28 . The section is not carried out through the vaporizer units  27 ,  51  to  60 . Visible is the wall  25  of vaporizer tube  3 . On the inside of wall  25  rests the cylinder  26  with the insulating layer  28 . The cylinder  26  is therein disposed on the guide rod  31 .  
         [0033]     On the insulating layer  28  vaporizer units  27 ,  51  to  60  are directly disposed, each of which includes heating elements  49 ,  61  to  70 , which are applied on the outer sides of  27 ,  51  to  60 . Between each of the vaporizer units  27 ,  51  to  60  is placed in each instance one insulating layer  50 ,  71  to  79 .  
         [0034]     Each vaporizer unit  27 ,  51  to  60  comprises a tub in which is located the material to be vaporized. However, only tub  37  of vaporizer unit  27  can be seen, in which the material  38  to be vaporized is made available. The vaporizer units  27 ,  51  to  60  are in contact on the upper piston  30  and on the lower piston  80 . Both pistons  30 ,  80  serve as guide elements for the vaporizer units  27 ,  51  to  60 . Cylinder  25  can consequently be moved together with the vaporizer units  27 ,  51  to  60  along the guide rod  31  either in the direction of the upper piston  30  or the lower piston  80 .  
         [0035]     The upper and lower piston  30 ,  80  are each provided with a heater  81 ,  82 , which are separated from the upper or the lower piston  30 ,  80  through an insulation  83 ,  84 . Between the heater  82  of the upper piston  30  and the heater  81  of the lower piston  80  can be seen a gap  85  through which the vaporized material reaches via the open region  29  the connection tube  4 , and lastly via the distributor  5 —as shown in  FIG. 1 —arrives on the substrate  24 .  
         [0036]     The lower piston  80  and the heater  81  disposed thereon can be moved back and forth in the direction of the upper piston  30  so that the size of the gap  85  can be varied.  
         [0037]     The vaporizer units are disposed parallel one above the other and are displaceable relative to one another along an imaginary common axis.  
         [0038]     In  FIG. 6  is shown a partial segment of the vaporizer tube  3  depicted in  FIG. 5 , with its wall  25  as well as the connection tube  4  with its wall  86 , the section also being carried out through the vaporizer units  27 ,  51  to  60 . Evident are only the vaporizer units  52  to  56 . The cylinder  26  extends through the guide rod  31  such that in  FIG. 6  the cylinder  26  is not visible.  
         [0039]     On guide rod  31  are disposed the insulating layer  28  and directly thereon the vaporizer units  52  to  56 . The vaporizer units  52  to  56  disposed on the cylinder  26  can thus be moved in the direction of the upper piston  30  or of the lower piston  80 . Each of the vaporizer units  52  to  56  include tubs  92  to  96 , in which is the material  87  to  91  to be vaporized.  
         [0040]     Although the vaporizer units  52  to  56  have been referred to as rings with tubs  92  to  96 , these vaporizer units  52  to  56  can also have a different shape. It is only important that these in that case also have a facility for receiving the material to be vaporized as well as include a heater.  
         [0041]     Since the vaporizer units  52  to  56  are each provided with a heater as well as possibly a cooling device, and thereby that the vaporizer units  52  to  56  are separated through insulating layer  72  to  76  from one another, each vaporizer unit  52  to  56  can be heated separately. In this way it is possible to vaporize only the material  89  located in the tub  94  of the vaporizer unit  54 . This vaporized material subsequently reaches through the gap  85  into region  29 . From this region  29  the vapor can lastly migrate through the distributor  5  ( FIG. 1 ) in the direction toward substrate  24 . The heaters  81 ,  82  of the upper piston  30  and of the lower piston  80  prevent the vapor from already condensing there on these pistons.  
         [0042]     Although not shown, it is understood that the connection tube  4  can also be equipped with heating elements in order to prevent there the condensation of the vapor.  
         [0043]     The vaporizer units  52  to  56  can be directly in contact on the upper or lower piston  30 ,  80  and insulating material can be disposed between the vaporizer units, so that the vapor can only escape through the gap  85  in the direction of the connection tube  4 .  
         [0044]     If not only the material  89  is to be vaporized from the tub  94  of the vaporizer unit  54 , the lower piston  80  can be moved in the direction of arrow  97 , such that the gap  85  is enlarged. If the lower piston  80  is moved for example by a length D in the direction of arrow  97 , with D corresponding to the inner diameter of the connection tube  4 , the material  90  of the vaporizer unit  55  can also escape from the gap now enlarged by D. It is advantageous for each vaporizer unit  52  to  56  to include its own heater. Thus, the vaporizer units can be heated individually, and specifically only those vaporizer units which are in the proximity of gap  86 .  
         [0045]     Consequently, the entire material located in the vaporizer tube  3  need not be heated, but only the material in those vaporizer units which are directly located on the gap. In addition, the material is available in portions and is therefore also only heated in portions. This has the advantage that material which cannot withstand long thermal loading, and consequently breaks down due to this loading, is only exposed to high temperature for a short time.  
         [0046]     As is evident in  FIG. 6 , it is possible that only the material  89  in tub  94  of the vaporizer unit  54  is vaporized. When the material  89  has been vaporized, another vaporizer unit, in which there is still material, is moved into the position of the vaporizer unit  54  and the material located in this vaporizer unit is vaporized.  
         [0047]     It is advantageous not to wait until the material  89  from vaporizer unit  54  has been completely vaporized. In order to ensure a continuous process with constant vaporizer rate, a measuring instrument is preferably utilized with which the vaporization rate can be determined.  
         [0048]     It is for example possible to determine through IR measurement the concentration of the vaporized material by having the connection tube  4  serve as a measuring cell, wherein the connection tube  4  comprises two opposing windows  98 ,  99  through which IR light radiation is transmitted. Utilizing the mathematical method of chemometry, the concentration of the vaporous material can subsequently be determined.  
         [0049]     If the concentration falls below a certain value, another vaporizer unit is brought into the position of the vaporizer unit  54  and the material located in this vaporizer unit is vaporized.  
         [0050]     If the vaporizer rate is to be increased, this is possible, for one, by raising the vaporization temperature and, for another, by enlarging the gap  85 . By enlarging gap  85  additional vaporizer units are located in the proximity of gap  85 , whereby the material located in these vaporizer units can also be vaporized. Depending on the size of the gap, a different number of vaporizer units are also selected and therewith also the quantity of material to be vaporized, whereby a finely graduated rate regulation is possible.  
         [0051]     Due to these vaporizer units with only a certain quantity of material, it is not necessary to vaporize the entire material located in the vaporizer tube  3 . Thus the portioned quantities of material in the particular vaporizer units are only exposed to the high temperatures for a relatively short time, whereby the material is vaporized before is can break down due to the thermal loading.  
         [0052]     Through the large number of vaporizer units which can be brought into the position correct for the vaporization of material via the guide element, material can be continuously made available to the vaporization process. As a result a constant vaporization rate can be continuously ensured. The service life of the total installation is accordingly also long enough in order to be able to coat large areas also.  
         [0053]     In principle, two movements, independently of one another, relative to the vaporizer tube  3  fixed on the installation must be differentiated.  
         [0054]     In the one movement, which relates to the piston  30  or the piston  80 , one of the two pistons is fixed on the vaporizer tube  3 . The other piston is for example driven via a vacuum-tight linear slide guide from outside of the vacuum. Which of the two pistons  30 ,  80  is fixed and which is movable does not affect the function.  
         [0055]     The other movement, regarding the movement of the vaporizer units, can also take place via vacuum-tight slide guides which are driven from outside of the vacuum. The vaporizer units are connected with rods in openings  40  to  42  to form a unit, including the insulations.  
         [0056]     Various embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.