Patent Publication Number: US-2011073038-A1

Title: Gas distribution plate and apparatus using the same

Description:
FIELD OF THE INVENTION 
     The present invention relates to a gas supply technique, and more particularly, to a gas distribution plate and the apparatuses using the same that is capable of supplying at least two reaction gases. 
     BACKGROUND OF THE INVENTION 
     With rapid advance and popularity of using means of chemical vapor deposition (CVD) in thin film coating process, it is becoming more and more important to have a gas distribution module capable of spraying gases into its corresponding reaction chamber uniformly. 
     Please refer to  FIG. 1 , which shows the arrangement of a common gas distribution module. As shown in  FIG. 1 , there is a carrier  11  being arranged inside a chamber  10  for carrying a substrate  12  to be processed while enabling the substrate  12  to be located at a position corresponding to an inlet channel  100  of the chamber  10 . Moreover, the inlet channel  100  is connected with a gas distribution module  13 , whereas the gas distribution module  13  can be a metal circular plate having a plurality of hole formed therein in a symmetrical manner so as to enable the gases entering into the chamber  10  through the inlet channel  100  to be sprayed uniformly onto the substrate  12 . However, the uniformity resulting from the aforesaid conventional gas distribution module  13  is usually not satisfactory that it is common to have a buffer zone  14  arranged between the inlet channel  100  and the gas distribution module  13  for improvement, by that the gases entering from the gas distribution module can first be stabilized by the buffering of the buffer zone  14  before it is sprayed inside the chamber  10  through the gas distribution module  13 , as shown in  FIG. 2 . 
     Nevertheless, the aforesaid arrangement is only proper for thin film coating process using low-flow gas, but is not capable of handling those thin film coating processes using high-flow gas since the use of simply only a layer of buffer zone  14  and the gas distribution module  13  is not sufficient. As shown in  FIG. 3 , when the gas entering area is fixed, the larger the flow is, the faster the gas is going to flow, by that the gas flowing through the center of the gas distribution module  13  will flow faster than those through the sides thereof, and thus more gas is going to accumulate at the center of the substrate  12  while causing the coating process with prove uniformity. 
     There are already many studies relating to the improvement of the gas distribution module. One of which is a gas distribution module disclosed in U.S. Pat. No. 6,921,437. In this gas distribution module, since the gases to be used in a coating process will be mixed in advance, not only it is unsuitable for those coating processes requiring the use of more than one gases that can not be mixed in advance for preventing they from reacting with each other, but also it can not be achieved without the use of some very complex piping arrangement and thus it can be very difficult to build and very costly as well. 
     Another such study 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. However, although the aforesaid gas distribution design is capable of enabling gases to be mixed and spray with sufficient uniformity, it is still very difficult and costly to build since its structure is very complex. 
     One another such study is disclosed in U.S. Pub. No. 2007/0163440, which describes a gas separation type showerhead. Although the aforesaid showerhead is capable of delivering gases with sufficient uniformity without having the gases to be mixed in advance, it is still disadvantageous in that: the showerhead can be very difficult and costly to build since its structure is very complex. 
     Furthermore, another such study is disclosed in U.S. Pat. No. 6,148,761, which describes a dual channel gas distribution plate. The dual channel gas distribution plate, being provided as a portion of a gas delivery system to a process chamber, has at least two sets of gas pathways disposed therein for allowing at least two separate gases to be delivered independently into a process chamber. In one embodiment, a first gas pathway, which includes a first set of vertical channels, is formed through the gas distribution plate, and a second gas pathway, which includes a second set of vertical channels, is formed through a portion of the gas distribution plate and connected to a set of interconnecting horizontal channels in the gas distribution plate, where the second gas pathway maintains fluidic separation from the first gas pathway, prior to the gases entering the process chamber. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a gas distribution plate and the apparatuses using the same that is capable of supplying at least two gases into a process chamber through their corresponding independent gas flowing channels while maintaining fluidic separation between the gas flowing channels prior to the gases entering the process chamber. 
     Another object of the invention is to provide a gas distribution apparatus, configured with tapered openings connected to the independent gas flowing channels of its gas distribution plate, by that the flow speeds of the gases are reduced so as to diffuse them and thus enable the same to be mixed completely prior to the gases entering the process chamber. 
     In one embodiment of the invention, the present invention provides a gas distribution plate, which comprises: a frame, having a recess formed at the center thereof; a first channel, connected to the recess by an end thereof while enabling another end thereof to penetrate the frame; a tapered opening, capable of communicating with the first channel; and at least a second channel, formed on the frame while enabling the same to communicate with the tapered opening. 
     In another embodiment of the invention, the present invention provides a gas distribution apparatus, which comprises: a gas guidance section, for guiding the flow of a first gas; a gas distribution plate, connected to the gas guidance section and comprising: a frame, having a recess formed at the center thereof; a plurality of first channels, each being configured for enabling the same to communicate with the gas guidance section so as to received the first gas therefrom; a plurality of second channels, being arranged in a manner that there is at least one such second channels disposed at a side of each first channel to be used for guiding the flow of a second gas; and a plurality of tapered openings, each being formed for enabling the same to communicate with one corresponding first channel and the at least one second channels disposed at the side of the corresponding first channel. 
     Furthermore, in another embodiment of the invention, the present invention provides a gas distribution plate, comprising: a frame with a first surface and a second surface, having a recess formed at the center thereof; a first channel, being formed penetrating through the recess of the frame; a second channel, formed inside the frame while allowing the center axis of the second channel to align parallel with the first surface; and a third channel, formed on the second surface of the frame while allowing the same to communicate with the second channel; wherein, the first channel further has a first tapered opening located on the second surface, and the third channel further has a second tapered opening located on the second surface. 
     In addition, in another embodiment of the invention, the present invention provides a gas distribution apparatus, comprising: a gas guidance section, for guiding the flow of a first gas; a gas distribution plate, connected to the gas guidance section and comprising: a frame with a first surface and a second surface, having a recess formed at the center thereof; a plurality of first channels, each being formed penetrating through the recess of the frame to be used for guiding the flow of a second gas; a plurality of second channels, each being formed inside the frame while allowing the center axis of each second channel to align parallel with the first surface so as to be used for guiding the flow of the first gas; and a plurality of third channel, formed on the second surface of the frame while allowing the same to communicate with their corresponding second channels; wherein, each first channel further has a first tapered opening located on the second surface, and each third channel further has a second tapered opening located on the second surface. 
     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  to  FIG. 3  show the arrangement of a common gas distribution module and the operation thereof as well. 
         FIG. 4A  is a top view of a gas distribution plate according to a first embodiment of the invention. 
         FIG. 4B  is an A-A sectional view of  FIG. 4A . 
         FIG. 5A  and  FIG. 5B  are schematic diagrams showing respectively the arrangement of a second channel and a first channel. 
         FIG. 6  is a schematic diagram showing a gas distribution apparatus according to a first embodiment of the invention. 
         FIG. 7A  and  FIG. 7B  are respectively a top view and an A-A sectional view of a first frame used in the embodiment of  FIG. 6 . 
         FIG. 7C  is a schematic diagram showing a first frame according to another embodiment of the invention. 
         FIG. 8  is a sectional view of a gas distribution apparatus using the gas distribution plate of  FIG. 4A . 
         FIG. 9  is a schematic diagram showing how a first gas and a second gas are flowing in a gas distribution plate of the invention. 
         FIG. 10A  and  FIG. 10B  are respectively a top view and a D-D sectional view of a gas distribution plate according to a second embodiment of the invention. 
         FIG. 11  is a schematic diagram showing a gas distribution apparatus according to a second embodiment of the invention. 
         FIG. 12A  and  FIG. 12B  are respectively a top view and a sectional view of a first frame used in the embodiment of  FIG. 11 . 
         FIG. 13A  and  FIG. 13B  are schematic diagrams showing how a first gas and a second gas are mixed with and without the formation of tapered openings in respective. 
     
    
    
     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. 4A  and  FIG. 4B , which is a top view of a gas distribution plate according to a first embodiment of the invention and an A-A sectional view of  FIG. 4A . As shown in  FIG. 4A  and  FIG. 4B , the gas distribution plate  20  comprises: a frame  200 , a plurality of first channel  201 , a plurality of tapered openings  202 , and a plurality of second channel  203 . It is noted that the front end of each first channel  201  is formed as a straight hole while allowing the rear end of each first channel  202  to connect to its corresponding tapered opening  202 . Moreover, the frame  200 , being formed with a first surface  2000  and a second surface  2001 , is configured with a recess  2002  at the center thereof as the recess  2002  can be formed by a means selected from the group consisting of: a means for performing a mechanical process upon the center of the frame  200 , and a means for welding pieces of the frame  200  together while allowing the recess  2002  to be formed at the center thereof. In addition, there is at least one gas supply channel  2003  formed on the sidewall of the recess  2002  at a position where can be selected at will. In this embodiment, there are two gas supply channels  2003  being arranged respectively at the two sidewalls of the recess  2002 . However, the amount of such gas supply channels  2003  capable of being formed on each sidewall is not limited thereby and thus there can be more than two such gas supply channels  2003  being formed on each sidewall as required. 
     In this embodiment, each first channel  201  is configured boring through the bottom of the recess  2002  and the second surface  2001  so as to connect an end of the referring first channel  20  with the recess  2002 . In addition, for each first channel  201 , there is at least one second channel  203  formed at a side thereof. It is note that the amount of such second channel  203  for each first channel  201  can be determined at will, nevertheless, there are six second channel  203  for each first channel  201  that is disposed surrounding the tapered opening  202  of the referring first channel  201  while enabling each second channel  203  to connect with referring first channel  201  by an end thereof and simultaneously connect with the recess  2002  by another end thereof. Please refer to  FIG. 5A  and  FIG. 5B , which are schematic diagrams showing respectively the arrangement of a second channel and a first channel. In  FIG. 5A , the center axis  90  of the second channel  203  is arranged parallel with the center axis  91  of the first channel  201 . However, in  FIG. 5B , the first and the second channels  201 ,  203  are arranged for forming an included angle θ between the center axis  90  of the second channel  203  and the center axis  91  of the first channel  201 . 
     Please refer to  FIG. 6 , which is a schematic diagram showing a gas distribution apparatus according to a first embodiment of the invention. The gas distribution apparatus  2  employs the gas distribution plate of  FIG. 4  as its gas distribution mechanism for enabling two separate gases to be delivered independently into a process chamber. In this embodiment, the gas distribution apparatus  2  is disposed on a process chamber  3 , whereas the process chamber  3  can be a process chamber designed for performing chemical vapor deposition (CVD) process, or for physical vapor deposition (PVD) process, or for an etching process, but is not limited thereby. It is noted that there is a carrier  30  being arranged inside the process chamber  3  for carrying a substrate  31  to be processed and the substrate  31  can be a silicon substrate or a glass substrate, but is not limited thereby. Moreover, the gas distribution apparatus  2  further comprises: a gas guidance section  21 ; and a gas distribution plate  20 , being arranged connecting to the gas guidance section  21 ; in which the gas guidance section  21  is coupled to a first gas source  22  for guiding the flow of a first gas from the first gas source  22  to the gas distribution plate  20 ; and the gas distribution plate  20  is further composed of: a first frame  210 , a second frame  211  and a third frame  212  in a manner that the first frame is disposed on the first surface  2000  of the frame  200 . 
     Please refer to  FIG. 7A  and  FIG. 7B , which are respectively a top view and an A-A sectional view of a first frame used in the embodiment of  FIG. 6 . As shown in  FIG. 7A  and  FIG. 7B , the first frame  210  has a first recess  2100  formed on a top side thereof and a plurality of protruding tubes  2101  at a bottom side thereof opposite to the top side while enabling each tube to communicate with the first recess  2100  by an end thereof as each is further capable of communicate with its corresponding first channel  210  through another end thereof. Similarly, the second frame  211  has an air hole  2110  which is connected with the first gas source so as to be used for the first gas to flow therethrough; and the third frame  212 , being sandwiching between the first frame  210  and the second frame  211 , is configured with a second recess  2120  in a manner that there are a plurality of via holes  2121  formed on the bottom of the second recess  2120  while enabling the plural via holes  2121  to communicate with the first recess  2100 . In another embodiment as shown in  FIG. 8 , there is a gas distribution apparatus that is designed without the third frame and thus covering the second frame  211  directly on the first frame  210 . It is noted that the gas distribution apparatus  20  shown in  FIG. 6  is structurally the same as the one shown in  FIG. 4 , in that the second surface  2001  of the gas distribution apparatus  20  is connected to the process chamber  3  while allowing the at least one gas supply channel  2003  formed on the sidewall of the recess  2002  on the gas distribution apparatus  20  to communicate with the second gas source  23  so as to receive the flow of a second gas therefrom. 
     Please refer to  FIG. 7C , which is a schematic diagram showing a first frame according to another embodiment of the invention. As shown in  FIG. 7C , the first frame  210   a  is composed of a plate  2100   a  and the plural tubes  2101   a , in that the plate  2100   a  is formed with a first recess  2102   a  having a plurality of via holes  2103   a  formed therein while allowing the plural protruding tubes  2101   a  to be fitted to their corresponding via holes  2103   a . Different from that the first frame  210  and the plural protruding tubes  2101  are integrally formed or being assembled by welding, the first frame  210   a  and the plural protruding tubes  2101   a  shown in  FIG. 7C  can be assembled by screwing, or by tightly engagement, but is not limited thereby. Thereby, each of the plurality protruding tubes can be replaced independently when damaged without having to replace the whole first frame  210   a  so that not only the lifespan of the first frame  210   a  is prolonged, but also the maintenance cost is reduced. 
     Operationally, as soon as the first gas and the second gas, provided separately from the first gas source  22  and the second gas source  23 , are fed into the gas distribution apparatus  2 , the second gas will flow into the recess  2002  through the gas supply channel  2003 , and then from the recess  2002  into the second channel  203  as the recess is designed communicating with the second channel  203 ; and simultaneously, the first gas will flow into the second recess  2120  of the third frame  212  through the gas supply channel  2110  of the second frame  211 . Moreover, as there are via holes  2121  being formed on the bottom of the second recess  2120  that are designed communicating with the first recess  2100 , the first gas after being uniformly distributed in the second recess  2120  can be guided to flow into the first recess  2100  uniformly where the first gas is able to flow into the first channel  201  through the protruding tubes  2101 . 
     Please refer to  FIG. 9 , which is a schematic diagram showing how a first gas and a second gas are flowing in a gas distribution plate of the invention. When the first gas  92  flows into the tapered opening  202  of the first channel  201  through the protruding tubes  211 , the covering range of the air curtain  920  resulting from the spraying of the first gas  92  will becoming larger and larger in proportion to the distance of the first gas  92  being spraying away from the tapered opening  202 . It is because that the tapering of the tapered opening  202  will cause the flowing speed of the first gas  92  to slow down which is going to cause the spreading of the first gas  92 . At the same time, the air curtain  930  resulting from the spraying of the second gas  93  into the tapered opening  202  through the second channel  203  will come into contact with the spreading air curtain  920  of the first gas  92  and thereafter mixed with the first gas  92  at the region close to the frame  20 , so that the first gas  92  and the second gas  93  can be mixed in the early stage of their spreading and thus enabling the two the be mixed completely inside the process chamber  3  for enhancing the process efficiency of the process chamber  3 . However, if there is no such design as the tapered opening  202 , because of the flowing speeds of the first gas  92  and the second gas  93 , the two gases will not spread and mix with each other until they are being sprayed away from the frame  20  for a conceivable distance which will cause the process efficiency of the process chamber  3  to drop. Hence, by the tapered opening  202 , the first gas and the second gas can be mixed with each other properly after being sprayed away from the frame  20  so that process efficiency of the process chamber  3  is enhanced. 
     Please refer to  FIG. 10A  and  FIG. 10B , which are respectively a top view and a D-D sectional view of a gas distribution plate according to a second embodiment of the invention. In this embodiment, the gas distribution plate  40  has a frame  400 , a plurality of first channels  401 , a plurality of second channels, and a plurality of third channels  403 . The frame  400  is configured with a first surface  4000  and a second surface  4001  in a manner that there is a recess  4002  formed on the central area of the first surface  4000  by a means selected from the group consisting of: a means for performing a mechanical process upon the center of the frame  400 , and a means for welding pieces of the frame  400  together while allowing the recess  4002  to be formed at the center thereof. In addition, there is a groove  4003  disposed surrounding the periphery of the recess  4002  to be used for receiving air-tightness components. Moreover, the plural first channels  401  are formed inside the recess  4002  while enabling them to penetrate the recess  4002  and the second surface  4001 . Each of the plural first channels  401  has a first tapered opening  4010  formed at an end thereof close to the second surface  4001 . The plural second channels  402  are formed inside the frame  40  while enabling each of the plural second channels  402  to be arranged perpendicular to the first gas supply channel  405 . For the arrangement of the plural third channels  403 , there are more than one third channels  403  being formed on each of the plural second channels  402  on the second surface  4001  while allowing the same to communicate with their corresponding second channels  402 . Moreover, each third channel  403  is configured with a second tapered opening  404  as the tapered opening  404  is being located on the second surface  4001 . In addition, there is at least one first gas supply channel  405  formed in an area between the wall of the recess  4002  and the side of the frame  40  in a direction defined by the Y-axis of  FIG. 10A , while allowing each of the at least one first gas supply channel  405  to extend from its corresponding opening  4050  located on the first surface  4000  into the frame  40  and thus communicate with the second channel  402 . Moreover, there is at least one second gas supply channel  406  formed in an area between the wall of the recess  4002  and the side of the frame  40  in a direction defined by the X-axis of  FIG. 10A , while allowing each the at least one second gas supply channel  406  to be arranged boring through the frame from its third side  4004  to the fourth side  4005  and thus communicate with the recess  4002  through the opening formed on the sidewall of the recess  4002 . It is noted that the amounts of the first gas supply channel  405  and the second gas supply channels  406  are determined according to actual requirement and can be selected at will that they are not limited by those demonstrated in the embodiments of the invention, not to mention the locations of the openings relating to those gas supply channels. 
     Please refer to  FIG. 11 , which is a schematic diagram showing a gas distribution apparatus according to a second embodiment of the invention. The gas distribution apparatus employs the gas distribution plate of  FIG. 10A  as its gas distribution mechanism for enabling two separate gases to be delivered independently into a process chamber. In this embodiment, the gas distribution apparatus  4  is disposed on a process chamber  3 , which is characteristically the same as the aforesaid embodiment and thus will not describe further herein. The gas distribution apparatus  4  of  FIG. 11  comprises: a gas guidance section  41 ; and a gas distribution plate  40 , being arranged connecting to the gas guidance section  41 ; in which the gas guidance section  41  is coupled to a first gas source  42  for guiding the flow of a first gas from the first gas source  42  to the gas distribution plate  40 ; and the gas distribution plate  40  is further composed of: a first frame  410 , and a second frame  411 . Please refer to  FIG. 12A  and  FIG. 12B , which are respectively a top view and a sectional view of a first frame used in the embodiment of  FIG. 11 . The first frame  410  is disposed covering the first surface  4000  of the gas distribution plate  40  whereas the first frame  410  is configured with a first recess  4100  at the center thereof and the recess  4100  can be formed by a means selected from the group consisting of: a means for performing a mechanical process upon the center of the first frame  410 , and a means for welding pieces of the frame  410  together while allowing the recess  4100  to be formed at the center thereof. In addition, there is at least one guidance channel  4101  formed on the two sidewalls of the recess  4100  while enabling each to communicate with the first gas supply channel  405 . In this embodiment, there are three guidance channels  4104  formed on each sidewall of the recess  4100 , but it is not limited thereby. Moreover, for enhancing air tightness, there is a groove  4102  to be formed surrounding the periphery of the first recess  4100  to be used for receiving air-tightness components. Each first gas supply channel  405  is disposed boring inside the first frame  410  from an opening thereof located at a sidewall of the recess  4100  toward another opening located at the bottom of the first frame  410  while allowing the same to communicate with its corresponding first channel. In addition, the second frame  411 , being disposed covering on the top surface of the first frame  410 , is configured with a via hole  4110  capable of communicating with the first recess  4100  to be used for the first gas to flow therethrough. 
     As shown in  FIG. 10A  and  FIG. 11 , the via hole  4110  is connect to the first gas source  42  so as to guide the first gas of the first gas source  42  to flow into the first recess  4100  where it is further guided to enter the first gas supply channel  405  through the guidance channels  4101  and thus into the process channel through the second channels  402  and the third channels  403 . By the arrangement of the aforesaid first frame  410 , the gas first is distributed inside the first recess  4100  of the first frame  410 , and then is further being enabled to distribute uniformly as it is being guided into the second channels  402  of the frame  400  through the guidance channels  4101  before it is fed into the process chamber  3  through the third channels  403 . The second gas source  43  is connected to the second gas supply channel  406  formed on a side of the frame  40  to be used for providing the second gas, by that the second gas is guide to flow into the recess  4002  of the frame  40  through the second gas supply channel  406  and then is fed into the process chamber through the first channel  401 . With the aforesaid arrangement, the gas distribution apparatus  4  can allow two separate gases to be delivered independently into a process chamber  3  while enabling the gases to be mixed completely after entering the processing chamber  3 . Please refer to  FIG. 13A  and  FIG. 13B , which are schematic diagrams showing how a first gas and a second gas are mixed with and without the formation of tapered openings in respective. As shown in  FIG. 13A , there are tapered openings  404 ,  4010  formed in the frame  40  of the gas distribution apparatus  4 , by that the speeds of the gases flowing inside the gas channels are to slow down and thus cause those gases to spread, that is, it is going to cause the first gas  92  and the second gas  93  to mix with each other rapidly and uniformly. However, for the gas distribution apparatus  4  shown in  FIG. 13B , the first gas  92  and the second gas  93  will leave the gas distribution plate at a comparatively higher speed in respective that the two gases  92 ,  93  will not spread and mix until they are at certain distances away from the frame  40  since there is not tapered openings. 
     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.