Patent Publication Number: US-2010126418-A1

Title: Gas shower module

Description:
FIELD OF THE INVENTION 
     The present invention relates to a gas shower module, and more particularly, to a gas shower module for gas deposition chamber. 
     BACKGROUND OF THE INVENTION 
     With the advance of chemical vapor deposition (CVD) coating technology, the importance of the gas shower module for uniformly delivering a gas into a process region of a CVD deposition chamber is increasing. 
     Please refer to  FIG. 1 , which is a schematic view of a conventional gas shower module. In  FIG. 1 , there is a carrier  11  configured in a chamber  10  that is used for carrying and heating a substrate  12 . Accordingly, there is a gas channel  100  formed inside the chamber at a position corresponding to the substrate  12  while enabling the gas channel  100  to be connected to a gas shower module  13 . The gas shower module  13  is conventionally formed as a metal panel having a plurality of holes symmetrically distributed thereon, and is designed for enabling a gas that is being fed into the chamber  10  through the gas channel  100  to be distributed evenly onto the substrate  12 . 
     However, the degree of uniformity resulting from the aforesaid gas shower module is usually not satisfactory, and thus it is common to configure a buffer zone  14  in the chamber  10  at a position between the gas channel  100  and the gas shower module  13 , by that the gas being fed into the gas shower module  13  through the gas channel  100  will be directed to the buffer zone  14  whereby the inflowing of the gas can be buffered and stabilized before being fed into the gas shower module  13  for discharging, as another embodiment of the invention shown in  FIG. 2 . 
     The use of the aforesaid buffer zone is only suitable for low flow situation, and when it is used in a coating process requiring a high-flow gas, the resulting degree of uniformity is still not satisfactory even though the inflowing gas is distributed by the cooperation of the signal-layered buffer zone and the gas shower module. The reasoning is that: as the intake area of a signal central gas inlet designed in the gas shower module  13  is fixed, there will exist an unavoidable time lag between the gases that exist near the center of the gas shower module  13  and those existing at the outer perimeter when the gases are inflowing at a high speed in high flow situation. As shown in  FIG. 3 , there will be non-uniform gas concentrations around the center of the substrate  12  which may adversely affect the deposition of the high-flow coating process. 
     There are already many devices be provided for improving the aforesaid disadvantages. One of which is a gas distribution system disclosed in U.S. Pat. No. 6,921,437. As in the aforesaid gas distribution system, gases will be mixed in the showerhead of the system before they are discharged therefrom so that it is not suitable for discharging gases that are mutually reactive. Moreover, since the gas distribution network formed inside the aforesaid system is very complex that not only it is difficult but also it can be very expensive to fabricate. 
     Another such device is disclosed in U.S. Pat. No. 6,478,872, which describes a method of delivering gas into reaction chamber and shower head used to deliver gas. Although the aforesaid method and showerhead are quite capable of delivering gases with satisfactory degree of uniformity, its structure is still very complex and can be very expensive to manufacture. 
     Yet, another such device is disclosed in U.S. Pub. No. 2007/0163440, which is a gas separation type showerhead. Despite the aforesaid showerhead is able to prevent gases from mixing and reacting with each other before it is distributed and can deliver the mixed gas with satisfactory degree of uniformity, its structure is still very complex and can be very expensive to manufacture. 
     Except for the aforesaid shortcomings, those conventional gas shower module are usually formed as a circular disc, as the one shown in  FIG. 4 , which might be suitable for coating large-sized substrate. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a gas shower module for gas deposition chamber with gas channel, which comprises: at least a distributor, configured with at least one diffusion cell positioned therein along a first axial direction and a plurality of inlets respectively connecting to the gas channel and the diffusion cell; and a shower, further comprising: at least one shower channel positioned therein along a second axial direction; a plurality of gas-inlet passages, connected to the diffusion cell and the shower channel; and a plurality of gas-outlet passages, connected to the shower channel and the gas deposition chamber; wherein the distributor is connected to the shower for enabling the diffusion cell to communicate with the shower channel through the gas-inlet passages, and the first axial direction is not be parallel to the second axial direction. 
     Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein: 
         FIG. 1  is a schematic view of a conventional gas shower system. 
         FIG. 2  is a schematic view of another conventional gas shower system. 
         FIG. 3  is a schematic diagram showing gases are non-uniformly concentrated around the center of the substrate by the gas shower system of  FIG. 2 . 
         FIG. 4  shows a disc-shaped showerhead used in a conventional gas shower system. 
         FIG. 5  is a cross sectional view of a gas shower module for gas deposition chamber according to the present invention. 
         FIG. 6  is a three-dimensional diagram showing a gas shower module according to an embodiment of the invention relating to how its distributor and shower are assembled. 
         FIG. 7  is a top view of a gas shower module of the invention. 
         FIG. 8  is a bottom view of a gas shower module of the invention. 
         FIG. 9  is a three-dimensional diagram showing a gas shower module of the invention without cool blocks. 
         FIG. 10  is a C-C′ sectional view of  FIG. 7 . 
         FIG. 11  is an A-A′ sectional view of  FIG. 7 . 
         FIG. 12  is a D-D′ sectional view of  FIG. 7 . 
         FIG. 13  is a B-B′ sectional view of  FIG. 7 . 
         FIG. 14  is a three-dimensional view of a distributor of the invention as it is viewed from the top thereof. 
         FIG. 15  is a three-dimensional view of a distributor of the invention as it is viewed from the bottom thereof. 
         FIG. 16  is a bottom view of a distributor according to an embodiment of the invention. 
         FIG. 17  is a bottom view of a distributor according to another embodiment of the invention. 
         FIG. 18  is a top view of a shower of the invention. 
         FIG. 19  is an X-ray view of a shower of the invention. 
         FIG. 20  is an X-ray view of a gas shower module of the invention as the distributor and the shower are assembled. 
         FIG. 21  is a partial enlarged view of  FIG. 20 . 
         FIG. 22  is a X-directional pressure distribution diagram of a workpiece in a gas deposition chamber. 
         FIG. 23  is a Y-directional pressure distribution diagram of a workpiece in a gas deposition chamber. 
     
    
    
     DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     For your esteemed members of reviewing committee to further understand and recognize the fulfilled functions and structural characteristics of the invention, several exemplary embodiments cooperating with detailed description are presented as the follows. 
     Please refer to  FIG. 5 , which is a cross sectional view of a gas shower module for gas deposition chamber according to the present invention. As shown in  FIG. 5 , there is a carrier  21  disposed in a chamber  20  in a manner that one side of the carrier is provided for carrying a substrate  22  for processing and heating while another side of the carrier  21  is connected to a lifting device  210  for adjusting the height of the carrier  21 . The chamber  20  is composed of a rectangular-shaped tank  31  and a cap  32 , in which there are a distributor  23  and a shower  24  disposed over the substrate  22  while being connected with each other. The distributor is configured with a first inlet  230   a  and a second inlet  230   b  in that the first inlet  230   a  is connected with a gas channel  200  while the second inlet  230   b  is connected with another gas channel  201 . The two gas channels  200 ,  201  are further connected to intake holes formed on the cap  32  so that a first gas and a second gas can be introduced therefrom is respective without mixing, i.e. there are two different gases being introduced into the system respectively through the two gas channels  200 ,  201 . 
     Please refer to  FIG. 6 ,  FIG. 7  and  FIG. 8 , which are respectively a three-dimensional diagram showing a gas shower module according to an embodiment of the invention relating to how its distributor and shower are assembled, and a top view and a bottom view thereof. In this embodiment, the gas shower module is composed of two distributors  23  and a shower  24 . Similarly, each distributor  23  is configured with two inlets  230   a,    230   b  while enabling the two inlet  230   a,    230   b  to be connected respectively to two gas channels  200 ,  201  in a gas deposition chamber. Moreover, there are two cooling blocks  25  being attached respectively to two sides of the shower  24  whereas the each cooling block  25  is formed with a cooling water conduit  250  therein in a manner that one cooling water conduit  250  in one of the two cooling block  25  is selected to be used for allowing cooling water to flow into the system therefrom and thus another cooling water conduit  250  in another cooling block  25  is used for allowing cooling water to flow out of the system therefrom. As shown in  FIG. 9 , there are a plurality of shower channel  242  and a plurality of cooling passages  251  formed inside the shower  24 . Moreover, the two ends of each cooling passage  251  are connected respectively to the two cooling water conduits  250  of the two cooling blocks  25  so that a cooling water flowing in one cooling water conduit  250  of one of the two cooling block  25  can be guided to flow in and out of the shower  24  through the cooling passages  251  and thus into another cooling water conduit  250  of another cooling block  25  where it is discharged. In this embodiment, there are a plurality of screw holes formed at positions surrounding the circumference of the diffusion cell in the distributor  23  for enabling the distributor  23  to be assembled with the shower  24  by screwing screws n into corresponding screw holes. In addition, for achieving air tight, a rubber pad is sandwiched between the distributor  23  and the shower  24 . Similarly, as there can are also a plurality of screw holes formed at positions surrounding the circumference of the cooling passages in the each cooling block  25  so that each cooling block  25  can be attached to the shower  24  by screwing, also for achieving air tight, there is a rubber pad being disposed between the cooling block  25  and the shower  24 . 
     Please refer to  FIG. 10 , which is a C-C′ sectional view of  FIG. 7 . As shown in  FIG. 10 , there are two distributors  23  disposed on top of the shower  24  while the shower  24  has two cooling blocks  25  attached to the two sides thereof; and the two cooling water conduit formed inside the two cooling block  25  as elongated holes are used for allowing cooling water to flow in and out of the shower  24 . 
     Please refer to  FIG. 11 , which is an A-A′ sectional view of  FIG. 7  without showing the two cooling blocks. As shown in  FIG. 11 , each distributor  23  is formed with two inlets  230   a  and  230   b  to be used for allowing two different gases filled in different gas channels to flow into the two diffusion cells  231  of the distributor  23  in respective, by that the flow of the two different gases, i.e. the first gas and the second gas, can be buffered in the two diffusion cells  231  and thus spread therein. In addition, the shower  24  is formed with at least a shower channel  242  that each is connected to one of the diffusion cells  231  by gas-inlet passages  243  for allowing the gas in the corresponding diffusion cell  231  to flow into the shower channel  242  therethrough. Moreover, the shower channel  242  is further connected to gas-outlet passages  240  so that the gas in the shower channel  232  can be sprayed into the gas deposition chamber therethrough. 
     Please refer to  FIG. 12 , which is a D-D′ sectional view of  FIG. 7 . Since the two cooling blocks are attached to the two sides of the shower  24 , the shower  24  is not visible in  FIG. 12 . As shown in  FIG. 12 , each cooling block  25  is fixed to the shower  24  by screwing screws n into the screw holes  241 . 
     Please refer to  FIG. 13 , which is a B-B′ sectional view of  FIG. 7 . For distributing gas evenly, the distribution of the shower channels  242  is arranged in a dense-sparse-dense manner in  FIG. 13 . However, it can also be distributed in an equidistant manner. Moreover, the shower channels  242  are connected to the diffusion cells in an alternating manner that each shower channel  242  can allow only one gas to flow therein. In addition, the cooling passages  251  and the shower channels  242  are disposed parallel with each other in the shower  24 . 
     Please refer to  FIG. 14  and  FIG. 15 , which are respectively a three-dimensional view of a distributor of the invention as it is viewed from the top thereof and a three-dimensional view of the same viewed from the bottom thereof. As shown in  FIG. 15 , there are sunken areas formed at one side of the distributor  23  to be used as diffusion cells  231 , and for achieving airtight, the distributor  23  is formed with a groove  232  at a position surrounding the circumference of each diffusion cell  231  for receiving a sealing member like an  0 -ring therein. It is noted that the side of the distributor  23  where the sunken areas are formed should be positioned facing toward the shower  24  for assembling the two. 
     Please refer to  FIG. 16  and  FIG. 17 , which are respectively the bottom views of two distributors according to different embodiments of the invention. In  FIG. 16 , there are two independent diffusion cells  231  formed on the distributor  23  in a manner that the two diffusion cells are surrounded by their corresponding grooves  232  and connected to their corresponding inlets  230   a,    230   b  in respective for separating the two completely from each other. Thereby, the distributor of  FIG. 16  is suitable for a coating process that requires gases to be prevented from mutually reacting before discharging. However, in the distributor  23  shown in  FIG. 17 , there is only a single diffusion cell  231  formed therein that is also surrounded by a groove  232  and connected to two inlets  230   a,    230   b.  Therefore, it is suitable for a coating process that requires gases to be mutually reacting before discharging. 
     Please refer to  FIG. 18 , which is a top view of a shower of the invention. As shown in  FIG. 18 , the gas-inlet passages  243  are formed on the shower  24  at a side thereof facing toward the distributor  23  while enabling the same to be disposed alternatively at positions corresponding to the shower channel of the shower  24 . It is noted that except for the alternating disposition as those shown in  FIG. 18 , the gas-inlet passages  243  can be distributed evenly. 
     Please refer to  FIG. 19 , which is an X-ray view of a shower of the invention. In  FIG. 19 , the plural shower channels  242  can be formed inside the shower  24  by drilling as the shower  24  is generally a metal block. In this embodiment of  FIG. 19 , the shower channels  242   a  and  242   b  are grouped as one shower channel  242  for example. Thereafter, there are holes being formed on the shower channels  242  while enabling the holes relating to one side of the shower  24  to be used as the gas-inlet passages  243  and those relating to the opposite side of the shower  24  to be used as the gas-outlet passages  240 . Moreover, for preventing the shower  24  itself from being coated and thus clogged by the gas flowing therein when the gas is overheated, there are cooling passages  251  formed inside the shower  24  for allowing a cooling water to flow therein. As there are two cooling block  25  attached to the two sides of the shower  24  and the cooling water conduits  251  of the two cooling blocks  25  are connected respectively to the two ends of each cooling passages  251 , the cooling water is able to flow in and out the shower  24  for lower its temperature. 
     Please refer to  FIG. 20  and  FIG. 21 , which are respectively an X-ray view of a gas shower module of the invention as the distributor and the shower are assembled, and is a partial enlarged view of  FIG. 20 . As shown in the figures, the exemplary shower channel  242   a  and shower channel  242   b,  being grouped as one shower channel  242 , are connected respectively to the two diffusion cells  231   a  and  231   b  as the two diffusion cells  231   a,    231   b  are filled with two mutually reactive different gases that should not be mixed before spraying. When the distributor  23  is assembled with the shower  24 , the gas-inlet passages  243   a  will connected the diffusion cell  231  a to the shower channel  242   a  for allowing one of the two gases to flow into the shower channel  242   a,  and similarly, the gas-inlet passages  243   b  will connected the diffusion cell  231   b  to the shower channel  242   b  for allowing one of the two gases to flow into the shower channel  242   b.  Moreover, as the gas-inlet passages  243   a  and the gas-inlet passages  243   b  are alternatively disposed, such arrangement can facilitating the gases to be uniformly mixed after being sprayed. In addition, as the gases used in this embodiment are filled into their corresponding diffusion cells  231  of the distributor  23  in a first axial direction, and then they are guided to flow into the shower channel  242  of the shower  24  in a second axial direction, not only the gases can be distributed evenly on the whole planar surface for spraying, but also the gases can be separated from each other when they are flowing in the distributor  23  and the shower  24  but only can encounter with each other after being sprayed out of the shower  24 . Although there are only two distributors  23  in this embodiment, there can be only one distributor  23 , or more than three distributors  23  used in the gas shower module of the invention. 
     Please refer to  FIG. 22  and  FIG. 23 , which are a X-directional pressure distribution diagram of a workpiece in a gas deposition chamber and a Y-directional pressure distribution diagram of the same. It is noted from the aforesaid  FIG. 22  and  FIG. 23  that the ratio between the maximum pressure and minimum pressure that are exerted on the substrate in the vapor deposition chamber by the gas shower module of the invention in both X direction and Y direction are about 1.02 with 2.3% error, indicating that the gas shower module of the invention is quite capable of distributing gas uniformly on the substrate. 
     In the embodiments of the invention, the axial direction, i.e. referred as the X direction, along the extending of the diffusion cell is perpendicular and orthogonal to the axial direction, i.e. referring as the Y direction, along the extending of the shower channel. However, it is not limited thereby and can be varied by users according to actual requirement. But they shall not be arranged against the following principle, that is, the extending axial direction of the diffusion cell is never parallel with the extending axial direction of the shower channel. Moreover, there can be more than one inlet being formed in the distributor  23  despite that there is only one inlet used in the embodiments of the invention. Taking the embodiment shown in  FIG. 5  for instance, it is possible to guide a gas flowing in one gas channel to flow into more than two sub-channels simply by fitting a joint to the cap  32 , and thereby, guide the gas to be filled into a same diffusion cell  231  through more than one inlets respectively connected to those sub-channels. Nevertheless, the amount of the diffusion cell is determined according to whether the gases used in a coating process should be mixed before spraying and also according to actual requirement of users. For example, there can be two inlets for one diffusion cell, or two inlets for two independent diffusion cells, and so on. It is noted that the gas shower module is also applicable for those coating process requiring the use of more than three different gases. 
     For preventing the gas to flow directly into the shower channel through the gas-inlet passages and then being also directly sprayed out of the same through the gas-outlet passages, the gas-inlet passages and the gas-outlet passages not disposed directly in correspondence to one another. Moreover, the diameter of each gas-outlet passages should be ranged between 0.1 centimeter and 2 centimeters. 
     In the embodiments of the invention, the cooling passages in the distributor are linear tubes that are disposed parallel with the shower channel. However, it is not limited thereby and thus can be disposed unparallel to the shower channel. One embodiment is by placing the cooling passage and the shower channel in a stacking manner so that the two can be disposed unparallel with each other. However, the stacking arrangement will result a thicker, heavier, larger distributor that not only it is not practical, but also is more costly in manufacture. 
     From the above description, it is noted that the gas shower module not only can mix and distribute gases evenly on the whole spraying surface, but also since it can be manufactured by common processing means of drill and mill, it is comparatively easy and cheap to manufacture as well as it is easy to assembled. In addition, if it is required to perform two different coating processes in one gas deposition chamber as one of the two processes requiring its gases to be separated for preventing mutually reacting before discharging and another process requiring its gases to be mutually reacting before spraying, such two different coating processes can be performed simply by changing the distributor in the gas shower module accordingly. 
     With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.