Patent Publication Number: US-2006011298-A1

Title: Showerhead with branched gas receiving channel and apparatus including the same for use in manufacturing semiconductor substrates

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This patent application is related to and claims priority from Korean Patent Application 2004-55131, filed on Jul. 15, 2004, the contents of which are hereby incorporated by reference in their entirety.  
     BACKGROUND OF THE INVENTION  
      The present invention relates to showerheads and apparatus for manufacturing integrated circuit devices, and more particularly, to apparatus for processing a semiconductor substrate.  
      Manufacturing of semiconductor (integrated circuit) devices generally involves a plurality of processes, such as deposition, photolithography, etching, and ion implantation. A chemical vapor deposition method typically used in manufacturing semiconductor devices operates by permeating a selected source gas into a reaction chamber, where the pressure and temperature of the reaction chamber are maintained uniformly to deposit a desired thin film on the surface of a semiconductor wafer positioned in the chamber.  
      A typical chemical vapor deposition apparatus has a chamber that may be well purged/vacated. The chamber generally has a supporting stand on which a wafer is placed and a shower head for supplying source gases onto the wafer. The shower head typically includes an internal space defined by injection plates. Receiving channels are generally formed in top wall of the shower head, through which gases are received into the space from external sources. Pluralities of holes for injecting the gases received in the space onto the wafer are typically formed in the shower head.  
      In a typical shower head, as the receiving channels through which gases are received are formed in the centers of the top walls, the gases are non-uniformly distributed in the space. As a result, a thin film that is deposited on the wafer may have a central portion that is thicker than at the edge. Such a non-uniformity problem may become more severe as the diameter of the wafer increases.  
      When a PZT thin film is deposited on the wafer, the gases used as source gases generally include a metal organic source gas having a large atomic weight. Such gases generally do not stay in the space of the shower head for a long time due to the weight thereof. As such, they may be, essentially, directly injected onto the wafer. Therefore, the source gases may not be uniformly distributed in the space of the shower head and deposition uniformity may deteriorate. In addition, a heater block for heating the source gases received in the shower head is sometimes provided around the shower head. It may be difficult to control the temperature of the source gases when the source gases only stay in the shower head for a short time.  
      Such deposition shower heads are also commonly made of stainless steel. Source gases for forming the PZT thin film may react to the stainless steel in the region close to the injection plate of the shower head. As a result, particles may be generated and introduced into the chamber.  
     SUMMARY OF THE INVENTION  
      Embodiments of the present invention provide showerheads for use in an apparatus for manufacturing a semiconductor substrate. The showerheads include an injection plate defining a bottom face of a gas receiving space in the showerhead and a gas receiving channel extending within the injection plate. A plurality of exhausting holes in the injection plate are coupled to the gas receiving channel. The exhausting holes are configured to exhaust gas from the gas receiving channel to the bottom face of the gas receiving space. A plurality of channels extend through the injection plate from the bottom face of the gas receiving space configured to flow gas from the bottom face of the gas receiving space out of the space.  
      In other embodiments of the present invention, the showerhead is configured to be received in a chamber of the apparatus and a portion of the gas receiving channel is defined by an air gap defined by a side wall of the chamber and an outer wall of the injection plate positioned adjacent thereto. The gas receiving channel may be a branched channel including a plurality of respective division lines extending to respective ones of the plurality of exhausting holes. The division lines may be symmetrically arranged extending through the injection plate. A single receiving line configured to receive a gas into the gas receiving channel may be to the gas receiving channel and the division lines may be arranged with respect to the receiving line. A plurality of the division lines may include curved line portions extending in an arc circumferentially around the injection plate.  
      In further embodiments of the present invention, substrate treating apparatus for manufacturing a semiconductor substrate are provided including a showerhead as described above. The apparatus further includes a chamber and a supporting stand positioned in the chamber and configured to receiver a semiconductor wafer substrate thereon. The gas receiving channel may include a receiving line configured to receive a gas from outside the chamber, exhausting lines extending to the exhausting holes, and connection lines that branch from the receiving line and connect to the exhausting lines. The connection lines may include two connection lines and the connection lines may be symmetrically arranged with respect to the receiving line.  
      In other embodiments of the present invention, each of the connection lines includes a first division line divided from the receiving line and two second division lines divided from each of the first division lines. Each pair of the second division lines may be symmetrically arranged with respect to the associated one of the first division line. Each of the first division lines may include a curved line portion extending in an arc circumferentially around the injection plate and a straight line portion that extends from the curved line portion in an inward radial direction of the injection plate to define a straight line of a predetermined length. The curved line portion of each of the first division line may be an arc having a central angle of about 90° such that the straight line portions of each of the first division lines are arranged on a straight line. Each of the two second division lines divided from one of the first division lines may include a curved line portion that extends in an arc circumferentially around the injection plate and a straight line portion that extends from the curved line portion of the second division line in the radial direction of the injection plate in the inward radial direction to define a straight line of predetermined length, where the curved line portion of the second division line may be an arc having a central angle of about 45°. The curved line portion of the first division line may be an air gap formed between a side wall of the process chamber and an outer wall of the first injection plate.  
      In yet further embodiments of the present invention, the connection lines are arranged in the apparatus so that gas flows horizontally therein and the exhausting lines are arranged in the apparatus so that gas flows vertically therein. The connection lines connecting the receiving line to the exhausting lines may be arranged in a repeating pattern of dividing one line into two lines and of dividing each of the divided lines into two lines again a plurality of times between the receiving line and the exhausting lines. The connection lines may be configured to provide a substantially uniform pressure of gas injected from each of the plurality of exhausting holes.  
      In other embodiments of the present invention, the shower head further includes a second injection plate defining a bottom face of a second gas receiving space configured to receive a second gas. The second injection plate is positioned proximate the first injection plate and the second injection plate includes a second gas receiving channel configured to flow the second gas therein to the second space and a plurality of second channels extending through the second injection plate from the bottom face of the second gas receiving space configured to flow gas from the bottom face of the second gas receiving space out of the second gas receiving space. The first gas receiving space may be defined by a groove formed in a top surface of the first injection plate that defines a bottom face of the first gas receiving space, and the second gas receiving space may be formed by a groove formed in a top surface of the second injection plate that defines the bottom face of the second gas receiving space.  
      In further embodiments of the present invention, projections having a gas passage therein extend from the second injection plate to outlets of the plurality of channels extending through the first injection plate. The shower head may further include a first side wall arranged to surround the first injection plate and protrude above the first injection plate. A second side wall may be arranged to surround the second injection plate and protrude above the second injection plate and the projections may be insertion pipes. The second gas receiving channel may include a receiving line configured to connect to a gas supplying pipe, exhausting lines connected to a plurality of exhausting holes in the second injection plate that are configured to exhaust gas into the second gas receiving space and connection lines extending from the receiving line to the exhausting lines that are arranged in a repeating pattern of dividing one line into two lines and of dividing each of the divided lines into two lines again a plurality of times between the receiving line and the exhausting lines.  
      In yet other embodiments of the present invention, the substrate treating apparatus is a deposition apparatus. The first gas may be a material having larger atomic weight than an atomic weight of a material that comprises the second gas. The first gas may be a metal organic source gas. The first gas may be lead (Pb), zirconium (Zr), and/or titanimum (Ti), and the second gas may be oxygen. The second injection plate may be aluminum.  
      In further embodiments of the present invention, a substrate treating apparatus for performing a deposition process of forming a thin film on a substrate includes a chamber and a supporting stand arranged in the chamber such that a substrate is placed thereon. A shower head is arranged in the chamber to supply a gas onto the substrate placed on the supporting stand. The shower head includes injection plates arranged to form a plurality of layers such that spaces to which the gas is received are formed on the top surfaces of the injection plates. Each of the respective injection plates includes a gas receiving channel through which the gas is supplied to the space formed in the top surface thereof and holes that are channels through which the gas is exhausted from the space.  
      In yet other embodiments of the present invention, the gas receiving channel includes a receiving line connected to an outer supplying pipe and exhausting lines connected to the exhausting holes formed on the bottom of the second space. Connection lines are divided from the receiving line to be connected to the exhausting lines. The gas receiving line includes the two connection lines and the connection lines are symmetrical with each other based on the receiving line. The connection lines may be formed by repeating processes of dividing one line into two lines from the receiving line and of dividing each of the divided lines into two lines symmetrical with each other again at least once. The shower head may include a first injection plate arranged in the upper portion and a second injection plate arranged below the first injection plate. Protrusions inserted into the holes formed in the first injection plate and having holes inside are formed on the top surface of the second injection plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate example embodiments of the present invention and, together with the description, serve to explain principles of the present invention. In the drawings:  
       FIG. 1  is a cross-sectional view illustrating a deposition apparatus according to some embodiments of the present invention;  
       FIG. 2  is an exploded perspective view illustrating a first injection plate and a first side wall according to some embodiments of the present invention;  
       FIG. 3  is a perspective view illustrating the first injection plate of  FIG. 2  in a shower head according to some embodiments of the present invention;  
       FIG. 4  is an exploded perspective view illustrating a second injection plate and a second side wall according to some embodiments of the present invention;  
       FIG. 5  is a plan view of the first injection plate of  FIG. 2 ;  
       FIG. 6  is a plan view of the second injection plate of  FIG. 4 ;  
       FIG. 7  is a cross-sectional view illustrating source gas flow direction in the deposition apparatus of  FIG. 1  according to some embodiments of the present invention;  
       FIG. 8  is a perspective view illustrating a first injection plate in a shower head according to further embodiments of the present invention;  
       FIG. 9  is a cross-sectional view illustrating a deposition apparatus including a shower head according to further embodiments of the present invention;  
       FIG. 10  is a perspective view of the first injection plate of  FIG. 9  according to some embodiments of the present invention;  
       FIG. 11  is a perspective view of the second injection plate of  FIG. 9  according to some embodiments of the present invention; and  
       FIG. 12  is a cross-sectional view illustrating a deposition apparatus according to other embodiments of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      The invention is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity.  
      It will be understood that when an element or layer is referred to as being “on”, “connected to” or “coupled to” another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. Like numbers refer to like elements throughout. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.  
      It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.  
      Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.  
      The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.  
      Embodiments of the present invention are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments of the present invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the present invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an etched region illustrated as a rectangle will, typically, have rounded or curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region of a device and are not intended to limit the scope of the present invention.  
      Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.  
      Various embodiments of the present invention will now be described with reference to the figures. In some described embodiments, a shower head is used in an apparatus for performing a deposition process by way of example. However, in other embodiments, the shower head can be used in apparatus for performing various other semiconductor fabricating processes, such as an etching process. In addition, in some described embodiments, a metal organic chemical vapor deposition (MOCVD) apparatus is described by way of example. However, the shower head can be used with a variety of different types of chemical vapor deposition apparatuses in various embodiments of the present invention.  
       FIG. 1  is a sectional view of a metal organic chemical vapor deposition (MOCVD) apparatus according to some embodiments of the present invention. As shown in the embodiments of  FIG. 1 , the MOCVD apparatus includes a chamber  100  defining a space that may provide an environmentally controlled environment. An exhaust pipe  126  may be connected to an external pump. The exhaust pipe  126  is shown coupled through a wall of the chamber  100  so that the inside of the chamber  100  may be maintained at a desired pressure selected for a deposition process and so that reaction byproducts generated in the chamber  100  may be exhausted.  
      A supporting stand  120  is shown on which a semiconductor substrate, such as a wafer, may be placed. The supporting stand  120  is positioned at a bottom of the chamber  100  and supported by a support shaft  122 . The supporting stand  120  may be disk shaped. A heater  124  is positioned in the supporting stand  120  to resolve source gases supplied to the upper portion of the heater  124  and to supply heat to the inside of the chamber  100  to facilitate smooth deposition of the source gases onto a wafer W. Thus, the heater  124  may be used to control heating of the wafer W to a temperature suitable to activate deposition of the source gas delivered material on the wafer W.  
      In the embodiments of  FIG. 1 , ring-shaped liners  140  are arranged between an inner surface of sidewalls of the chamber  100  and the supporting stand  120  so as to surround the supporting stand  120 . The liners  140  may limit or prevent reacting of the inner surface of the sidewalls of the chamber  100  with the source gases and deposition of reaction byproducts on the inner surface of the walls of the chamber  100 .  
      A shower head  200 , configured to supply the source gases onto the wafer W on the supporting stand  120 , is positioned in the upper portion of the chamber  100 . The shower head  200  is shown facing the supporting stand  120 . Heaters  160  may be positioned around the shower head  200  to heat the source gases received in the shower head  200  so that the source gases are maintained at a selected temperature suitable for a deposition process. The heaters  160  may also operate to control liquefying or resolving of the source gases while the source gases are still in the shower head  200 , particularly when the source gases are metal organic precursor gases.  
      A source gas supplying portion configured to supply the source gases to the shower head  200  is arranged outside the chamber  100 . The source gas supplying portion in the embodiments of  FIG. 2  includes a first gas supplying portion  420  configured to supply a first source gas to the shower head  200  and a second gas supplying portion  440  configured to supply a second source gas to the shower head  200 . For example, the first source gas may include a metal organic precursor gas that has a low vapor pressure and is liquid/solid at room temperature and is supplied in a vapor state. The second source gas may be gaseous at room temperature and may react with the first source gas. For example, when a PZT film is deposited on the wafer W, the first source gas may include lead (Pb), zirconium (Zr), and titanium (Ti) and the second source gas may include oxygen (O). The illustrated first gas supplying portion  420  includes a gas supplying pipe  422  provided with a vaporizer  424  that supplies the metal organic precursor gas to the shower head  200 . A pipe  426  is coupled to the gas supplying pipe  422  at a selected location. The pipe  426  supplies a carrier gas that carries the vaporized metal organic precursor gas. An additional pipe (not shown) may also be coupled to the gas supplying pipe  422  to supply a fudge (e.g. purge/inert) gas. The second gas supplying portion  440  in the embodiments of  FIG. 1  includes a gas supplying pipe  442  that supplies a gas including O to the shower head  200 . Opening and closing valves  422   a,    426   a,  and  442   a  for opening and closing inner channels are shown in the respective pipes. The valves  422   a,    426   a  and  442   a  may also be configured to control an a flow rate or separate flow rate control valves may be provided in the respective pipes.  
      The shower head  200  of  FIG. 1  has a cylindrical body that defines therein a first space  202  in which the first source gas is received and a second space  204  in which the second source gas is received. The first space  202  and the second space  204  are surrounded by a top wall  290 , an injection plate  240  that defines a top wall of the second space  204  and a bottom wall of the first space  202 , an injection plate  260  that defines a bottom wall of the second space  204  and respective side walls  250  and  270  and are partitioned by layers. The injection plate  240  operates as an injection plate of the first space  202  and, at the same time, may function as the top wall of the second space  204 . The injection plate  240  separating the first and second space  202 ,  204  may be referred to herein as the first injection plate  240 . The injection plate  260  may be referred to as the second injection plate  260 . The top wall  290  of the first space  202  may be a separate part from the chamber  100  and the side wall  250  as illustrated in  FIG. 1 . However, the top wall of the chamber  100  may be used as the top wall of the first space  202  in other embodiments.  
      A metal organic source gas is generally much heavier than other gases used in semiconductor deposition processes. As a result, when the first source gas including the metal organic source gas is injected from the top to the bottom as shown in  FIG. 1 , the first source gas may not be well diffused through a wide region in the first space  202  but, instead, may be substantially directly injected from the shower head  200 . As such, the first source gas may be non-uniformly deposited across different regions of the wafer W and it is difficult to control the temperature of the first source gas in the shower head  200 . In some embodiments of the present invention, as illustrated in  FIG. 3 , the first source gas is injected from the bottom of the first space  202  to the first space  202  through a first gas receiving channel  300 . As the first source gas is received to the first space  202  while being diffused like a jet flow in such embodiments, the first source gas may be more uniformly supplied to a wide region. It is also generally more difficult to control the temperature of the first source gas than the temperature of the second source gas. Therefore, the first space  202  may be arranged above the second space  204 , such that the first source gas may stay in the shower head  200  for a longer time.  
      The first gas receiving channel  300  in the embodiments of  FIG. 3  includes a receiving portion, a dividing portion, and an exhausting portion. The receiving portion receives the first source gas from outside the shower head  200  and has a receiving line connected to the gas supplying pipe  422 . The exhausting portion exhausts the first source gas received in the shower head  200  to the first space  202  and has a plurality of exhausting lines in the illustrated embodiments of  FIG. 3 . The exhausting lines may be separated from each other at uniform intervals such that gases can be more uniformly received in the first space  202 . The dividing portion is divided from the receiving line and has connection lines for connecting the receiving line and the exhausting lines to each other.  
      Each of the connection lines may have a plurality of division (branch) lines. For example, each of the connection lines may include a first division line divided from (branching off of) the receiving line and the exhausting lines may be connected to the first division lines. However, each of the connection lines may further include a plurality of second division (branch) lines divided from the first division lines and the exhausting lines may be connected to respective ones of the second division lines. In addition, each of the connection lines may further include a plurality of third division (branch) lines divided from the second division lines and the exhausting lines may be connected to respective ones of the third division lines. That is, each of the connection lines may include a first division line, second division lines, . . . , (k−1)&#39;th division lines, . . . , nth division lines and one nth division line may be connected to one exhausting line. In some embodiments, the connection lines are formed so that the first source gas flows horizontally and that the exhausting lines are formed so that the first source gas flows vertically. However, the connection lines and/or the exhausting lines may be formed to provided inclined (angled) flow of the first source gas.  
      The first source gas in some embodiments is exhausted from the exhausting lines under the substantially same pressure so that the gas can be uniformly received into the first space  202 . When three or more k&#39;th division lines are divided from one (k−1)&#39;th division line and/or the k&#39;th division lines are not symmetrical with each other based on the (k−1)&#39;th division line, the pressure of the gas that flows inside the k&#39;th division lines may vary. As such, in some embodiments, the number of connection lines divided from the receiving line is two and the connection lines are symmetrical with each other relative to the receiving line. In some embodiments, two k&#39;th division lines are divided from one (k−1)&#39;th division line, the k&#39;th division lines are divided so as to be symmetrical with each other relative to the (k−1)&#39;the division line, and the exhausting lines are symmetrical with each other relative to the injection plate  240 .  
      One receiving line or a plurality of receiving lines may be provided in various embodiments. However, in some embodiments, when a plurality of receiving lines are provided, a plurality of gas supplying pipes are also provided, which may result in more complicated equipment and the pressure and the temperature of the first source gas that flows through the gas supplying pipe  422  may be non-uniform. In other embodiments, only a single receiving line is provided in the shower head  200 .  
      When the number of exhausting lines is too small, it may be difficult to uniformly supply the first source gas to the entire first space  202 . When the number of exhausting lines is too large, the number of exhausting lines in the injection plate may increase to a point where it is difficult to manufacture the injection plate and division/branching of the lines becomes so many times that the gas may not flow smoothly. Therefore, in some embodiments, where up to nth division are lines formed in the injection plate, n may be selected dependent on the area of the injection plate (generally corresponding to the size of the wafer to be processed in the apparatus). In particular embodiments, where a deposition process is to be performed on the wafer of 300 mm, n is 2 and/or 3.  
       FIG. 2  is an exploded perspective view illustrating the first injection plate  240  and the first side wall  250  according to some embodiments of the present invention.  FIG. 3  is a perspective view illustrating part of the first gas receiving channel  300  formed in the first injection plate  240  according to some embodiments of the present invention. The gas receiving and exhausting lines discussed generally above will now be described with reference to the particular illustrated embodiments of  FIGS. 2 and 3 . The illustrated gas receiving channel  300  includes a receiving line  320 , connection lines  340 , and four exhausting lines  360 . The receiving line  320  is illustrated as a horizontal straight line and is divided into two connection lines  340 . Note that, in  FIG. 3 , numbering is only shown with reference to a first one of the connection lines  340 , with the second portion of the distribution network (on the top as seen in  FIG. 3 ) shown as being symmetrical to the numbered portion. The receiving line  320  may be formed by a hole extending through a side wall of the chamber  100  and the first side wall  250  of the shower head. The exhausting lines  360  are connected to exhausting holes  362  ( FIG. 2 ) formed on a face of the injection plate  240  defining the bottom of the first space  202 .  
      As noted above, the two connection lines  340  are illustrated as formed to be symmetrical with each other about a line defined by the receiving line  320 . The connection lines  340  are shown as defining two first division lines  342  divided from the receiving line  320  and two second division lines  344  divided from the first division lines  342 . Each of the first division lines  342  includes a curved portion  342   a  that is an arc and a straight line portion  342   b  that extends from the curved line portion  342   a  toward the inside in the radial direction of the injection plate  240  to form a straight line of predetermined length. The curved line portion  342   a  of each of the first division lines  342  may be an arc having a central angle of about 90° so that the straight line portions  342   b  of the two first division lines  342  divided from the receiving line  320  are arranged along the same straight line, which may pass through a midpoint of the injection plate  240 . The illustrated two second division lines  344  branching from each straight line portion  342   b  are divided from the first division lines  342 , respectively, so as to be symmetrical with each other. Each of the second division lines  344  is illustrated as including a curved line portion  344   a  that is an arc and a straight line portion  344   b  that extends from the curved line portion  344   a  toward the inside in the radial direction of the injection plate  240  to form a straight line of predetermined length. The curved line portion  344   a  of each of the second division lines  344  may be an arc having a central angle of about 45°. The exhausting lines  360  in the illustrated embodiments connect to the first space  202  from the ends of the second division lines  344 . In some embodiments, the connection lines  340  are formed on a horizontal plane and the exhausting lines  360  are perpendicular to the connection lines  340 .  
      As seen in  FIGS. 1 and 2 , the first side wall  250  is arranged to surround the first injection plate  240  and extend above the top end of the first injection plate  240 . The first side wall  250  in the illustrated embodiments can be attached to and detached from the first injection plate  240  and may be coupled to the first injection plate  240  by conventional connection means, such as screws. The first side wall  250  associated with the first injection plate  240  may be formed so that an air gap  341  ( FIGS. 1 and 3 ) is formed between the first injection plate  240  and the first side wall  250  when the first injection plate  240  and the first side wall  250  are positioned in adjacent relationship to each other. The air gap  341  may be used as one of the above described division lines for receiving gas.  FIG. 3  illustrates some embodiments of the structure of the injection plate  240  to form the air gap  341 .  
      Referring again to the embodiments of  FIG. 2 , the inside of the first side wall  250  is formed to have a plurality of steps and the side surface of the first injection plate  240  has a plurality of steps formed to be engaged with the steps formed in the first side wall  250 . An intermediate step  245  of the first injection plate  240  is shown as being formed only over half of the circumference of the first injection plate  240 . Therefore, when the first injection plate  240  and the first side wall  250  are combined with each other, the air gap  341  of  FIG. 3  may be formed between the first injection plate  240  and the first side wall  250  (where the step  245  would otherwise extend). The receiving line  320  may be formed in the first side wall  250 , the air gap  341  may be provided as the curved portions  342   a  of the first division lines  342 , and the straight line portions  342   b  of the first division lines, the second division lines  344 , and the exhausting lines  360  may be formed as holes in the first injection plate  240 .  
      In some embodiments, the arrangement, the length, and the structure of the first division lines  342  and the second division lines  344  and the arrangement of the exhausting lines  360  may operate to maintain the first source gas at substantially the same pressure in the exhausting lines  360 . However, the arrangement, the length, and the structure of the first division lines  342  and the second division lines  344  and the arrangement of the exhausting lines  360  may take various other forms in further embodiments of the present invention.  
      In some embodiments of the present invention, the shower head is arranged so the second source gas be substantially uniformly injected downward into the shower head  200 . As seen in the embodiments of  FIG. 4 , a gas receiving channel  300 ′, which is a channel through which gases are transmitted to the second space  204 , is formed in the second injection plate  260 .  FIG. 4  is an exploded perspective view illustrating the second injection plate  260  and the second side wall  270 . Because the gas receiving channel  300 ′ formed in the second injection plate  260  for the embodiments illustrated in  FIG. 4  has substantially the same structure as the gas receiving channel  300  formed in the first injection plate  240 , detailed description thereof will be omitted herein. The gas receiving channel  300 ′ formed in the second injection plate  260  may be arranged on the opposite side of the gas receiving channel  300  formed in the first injection plate  240 , such that the arrangement of the gas supplying pipes  422  and  442  of  FIG. 1  may be simplified by providing separation therebetween. For example, if the gas receiving channel  300  is formed on the right side of the first injection plate  240 , the gas receiving channel  300 ′ may be formed on the left side of the second injection plate  260 . The gas receiving channel  300 ′ formed in the second injection plate  260  may further be arranged so as to face the gas receiving channel  300  formed in the first injection plate  240 .  
       FIGS. 5 and 6  are plan views of the first injection plate  240  and the second injection plate  260 , respectively, according to some embodiments of the present invention. As seen in the embodiments of  FIGS. 5 and 6 , a plurality of first holes  244   a  are formed in the first injection plate  240  and a plurality of second holes  264   a  and a plurality of third holes  264   b  are formed in the first injection plate  240 . The third holes  264   b  are formed so as to face the first holes  244   a  in an up and down direction and the first holes  244   a  and the third holes  264   b  that face each other are connected to each other by an insertion pipe  280  ( FIG. 1 ). The first holes  244   a  may be arranged at uniform intervals throughout the first injection plate  240  and the second holes  264   a  may be formed between the third holes  264   b  arranged at uniform intervals over the first injection plate  240 .  
      In some embodiments, the first injection plate  250  and the second injection plate  260  are made of a material that is substantially non-reactive with the source gases and the first side wall is made of a material that is substantially not transformed thereby. For example, the first injection plate  240  and the second injection plate  260  may be made of aluminum and the first side wall and the second side wall may be made of stainless steel. In particular embodiments, where a gas including Pb, Zr, and Ti and a gas including O are intended to coexist in the region under the shower head  200 , the inner plate  264  of the second injection plate  260  may be made of aluminum, which is generally not reactive with to these gases.  
       FIG. 7  illustrates the direction in which the source gases flow in the apparatus of  FIG. 1  according to some embodiments of the present invention. As seen in the embodiments of  FIG. 7 , the first source gas is exhausted to the first space  202  through the first gas receiving channel  300  formed in the first injection plate  240  and is substantially uniformly diffused into the first space  202 . The first source gas is then injected downward from the first space  202  in the shower head  200  through the insertion pipe  280 . The second source gas is exhausted to the second space  204  through the second gas receiving channel  300 ′ formed in the second injection plate  260  and is substantially uniformly diffused into the second space  204 . The second source gas is then injected downward from the second space  204  in the shower head  200  through the second holes  264   a.  As a result, when a deposition process is performed using a chemical vapor deposition method, the first source gas and the second source gas may be simultaneously supplied to a wafer W during the deposition process. When the deposition process is performed using an atomic layer deposition method, the first source gas and the second source gas may be sequentially supplied to the wafer W.  
      For some embodiments of the present invention using two kinds of source gas in the deposition process, both of the spaces  202  and  204  are formed in the shower head  200 . When three or more source gases are used for the process, three or more spaces may be formed in the shower bead  200 . Furthermore, when the process is performed using the atomic layer deposition method, a shower head  200  having the above-described multi-space structure may be used or a single space may be formed in the shower head  200  and the first source gas, the fudge gas (i.e., purging gas), and the second source gas may be sequentially supplied to the space. In such embodiments, the first division line  342   a  may be defined by a space between the first side wall  242  of the injection plate and the first injection plate  240 . Alternatively, as illustrated in  FIG. 8 , the first division lines  342   a  may be formed in the first injection plate  240 , like the other division lines, as holes.  
       FIG. 9  is a cross-sectional view illustrating a deposition apparatus including the shower head  200  according to further embodiments of the present invention.  FIG. 10  is a perspective view illustrating the first injection plate  240  according to some embodiments of the present invention.  FIG. 11  is a perspective view illustrating the second injection plate  260  according to some embodiments of the present invention. In the apparatus of the embodiments of  FIG. 9 , various of the features, excluding the structure of the shower head  200 , are substantially the same as the corresponding features illustrated in  FIG. 1  and detailed description thereof will be omitted. Also, as the shape, the structure, and the arrangement of the second gas receiving channel  300 ′ are substantially the same as the shape, the structure, and the arrangement of the first gas receiving channel  300 , detailed description thereof will be omitted. The apparatus illustrated in  FIG. 9  will now be described primarily with reference to differences between the apparatus illustrated in  FIG. 9  and the apparatus illustrated in  FIG. 1 .  
      Referring to the embodiments of FIGS.  9  to  11 , the shower head  200  includes the first injection plate  240  and the second injection plate  260 . The first injection plate  240  and the second injection plate  260  are arranged to be laminated in an up and down direction (as shown in the figures). A groove for providing the first space  202  is formed in the top surface of the first injection plate  240 . A groove for providing the second space  204  is formed in the top surface of the second injection plate  260 . In the inside wall of the chamber  100 , the portion with which the shower head  200  will contact is formed to have steps. The shower head  200  of the embodiments of  FIGS. 9-11  does not include the first side wall  250  and the second side wall  270  of the embodiments of  FIG. 1 . The first injection plate  240  and the second injection plate  260  may be directly combined with the chamber  100 .  
      The receiving line  320 ″ of the first gas receiving channel  300  and the second gas receiving channel  300 ″ are illustrated formed on the side wall of the chamber  100 . The curved line portions  344   a  of the respective first and second gas first division lines  344  (see  FIG. 3 ) are formed by air gap  341 ′ formed between the first injection plate  240  and the side wall of the chamber  100  and by air gap  341 ″ formed between the second injection plate  260  and the side wall of the chamber  100 , respectively. O-rings  170  are shown provided up and down the air gaps, which may limit or even prevent the gases received in the air gaps  341 ′,  341 ″ from being exhausted to the outside.  
      For some embodiments, the first holes  244   a  ( FIG. 10 ) are formed in the first injection plate  240  and the second holes  264   a  and the third holes  264   b  ( FIG. 11 ) are formed in the second injection plate  260 . Protrusions  266 , inserted into the first holes  244   a,  are formed on the top surface of the second injection plate  260  and the above-described third holes  264   b  are aligned with the protrusions  266 . The first source gas received in the first space  202  is injected downwardly through the protrusions  266  and the third holes  264   b.  The second source gas received in the second space  204  is injected downwardly through the second holes  264   a.    
      The second injection plate  260  may be made of aluminum, which may not react to the first source gas and/or the second source gas. The first injection plate  240  may be made of aluminum and/or stainless steel.  
       FIG. 12  illustrates a modification of the apparatus of  FIG. 9  according to further embodiments of the present invention. The first space  202  and the second space  204  in these illustrated embodiments may have enough height so that the gases received to the first space  202  and the second space  204  can be substantially uniformly diffused into the respective spaces. In particular, the first space  202 , where a metal organic precursor gas may be received as first source gas, may have a height selected to accommodate and distribute such a source gas. To provide a greater height, the embodiments of  FIG. 12  include a groove formed in the top surface of the chamber  100  that provides in combination with the first injection plate  240 , a first space  202  with an increased height as compared to the embodiments of  FIG. 9 .  
      With some embodiments of the present invention, as gases may be more uniformly injected from a shower head onto a wafer as compared with a conventional apparatus, a thin film may be more uniformly deposited on the entire target region of the wafer. In some embodiments, where a metal organic source gas may stay in the shower head for a long time, it may be possible to readily control the temperature of the source gases. The lowermost injection plate among the injection plates of the shower head may be made of aluminum in some embodiments, which may limit or prevent the injection plate from reacting to the source gases in the deposition chamber.  
      The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.