Abstract:
An apparatus for forming a thin film on a substrate includes a chamber having a gas inlet, an upper electrode in the chamber, the upper electrode having a plurality of nozzles, a lower electrode in the chamber for supporting the substrate thereon, the lower electrode being spaced apart from the upper electrode, and a selective injection plate above the upper electrode, the selective injection plate including a selective injection valve for selectively concentrating a gas supplied through the gas inlet onto a portion of the upper electrode.

Description:
[0001]     The present invention claims the benefit of Korean Patent Application No. 2004-0049527 filed in Korea on Jun. 29, 2004, which is hereby incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an apparatus and a method thereof for forming a thin film, and more particularly, to an apparatus for forming a thin film on a substrate and a liquid crystal display device manufactured using the same.  
         [0004]     2. Discussion of the Related Art  
         [0005]     Due to rapid development in information technology, display devices have to display large amounts of information. Although cathode ray tube (CRT) devices have been commonly used as display devices, flat panel display devices that are thin, light weight, and low in power consumption have been actively developed. Among these, liquid crystal display (LCD) devices have been widely used in notebook computer monitors, personal computer monitors, office automation instruments such as photocopiers, and handheld devices such as cellular phones and pagers, because of their superior image resolution, color image display, and display image quality.  
         [0006]     An LCD device includes an upper substrate, a lower substrate, and a liquid crystal material layer disposed between the upper and lower substrates. The LCD device uses optical anisotropy and birefringence characteristics of liquid crystal molecules in the liquid crystal material layer to produce image data by controlling an electric field applied to the liquid crystal material layers, thereby altering an arrangement of the liquid crystal molecules and varying light transmittance thereof.  
         [0007]     An LCD device also includes a thin film transistor that functions as a switching element. Such an LCD device that includes the thin film transistor is commonly referred to as an active matrix liquid crystal display (AMLCD) device. An AMLCD device has high image resolution and can display moving images.  
         [0008]     In general, an AMLCD device is manufactured through processes of cleaning substrates, forming patterns on the substrates, forming alignment layers, attaching the substrates, forming a liquid crystal layer between the substrates, and packaging circuits. The process of cleaning the substrates may be performed before and after the process of forming the patterns on the substrates, and particles on the substrates are removed by cleaning agents during the process of cleaning the substrates.  
         [0009]     In addition, the process of forming patterns on the substrates is divided into a process of forming patterns on an upper substrate and a process of forming patterns on a lower substrate. During the process of forming patterns on the upper substrate, a color filter layer, a black matrix and a common electrode are formed on the upper substrate. During the process of forming patterns on the lower substrate, gate lines and data lines crossing each other to define pixel regions, a thin film transistor connected to each crossing of the gate and data lines, a pixel electrode connected to the thin film transistor in each pixel region are formed on the lower substrate.  
         [0010]     Further, alignment layers are coated on respective substrates after patterns are formed thereon and are rubbed. Next, a sealant may be formed on the lower substrate to attach the lower and upper substrates. Liquid crystal then is injected between the attached substrates through an injection hole to form a liquid crystal layer, and the injection hole is sealed.  
         [0011]     Moreover, the attached substrates including the liquid crystal layer therebetween passes through another cleaning process and a grinding process to form a liquid crystal panel. Integrated circuits are attached to the liquid crystal panel.  
         [0012]     Apparatuses for manufacturing a liquid crystal display device include airtight chambers so that the processes are performed under high vacuum. A cluster chamber, which can treat a plurality of substrates in a short time, has been widely used. A cluster chamber includes process chambers, a load lock chamber, and a transfer chamber. In particular, in the process chambers, processes for directly treating substrates are performed. The transfer chamber stores the substrates and transfers the substrates into or out of the process chambers. The process chambers include a chamber for a plasma enhanced chemical vapor deposition (PECVD) apparatus and a chamber for a dry etch apparatus.  
         [0013]      FIG. 1  is a cross-sectional view illustrating a dry etching apparatus for manufacturing a liquid crystal display device according to the related art, and  FIG. 2  is a plan view illustrating an upper electrode of the dry etching apparatus shown in  FIG. 1 . As shown in  FIG. 1 , a dry etching apparatus includes a gas inlet  12  formed in an upper side of a chamber  10  and a gas outlet  11  formed in a lower side of the chamber  10 . Gases are injected into the chamber  10  through the gas inlet  12  from a gas-storing unit (not shown) and exhausted from the chamber  10  through the gas outlet  11 .  
         [0014]     In addition, the chamber  10  includes a lower electrode  21  and an upper electrode  31  spaced apart from each other. A substrate  22 , which includes a thin film to be patterned, is loaded on the lower electrode  21  inside the chamber  10 . In particular, the lower electrode  21  is connected to an outer power supplier  13 , which applies a radio frequency (RF) power to the lower electrode  21 .  
         [0015]     Further, the space between the lower electrode  21  and the upper electrode  31  often is referred to a reaction region. In particular, the upper electrode  31  is grounded and has a plurality of holes  32 . As shown in  FIG. 2 , the holes  32  are arranged in a matrix manner across the upper electrode  31 .  
         [0016]     Referring back to  FIG. 1 , the chamber  10  further includes gas injection plates,  41 ,  42  and  43 , disposed over the upper electrode  31  for evenly distributing the gases injected through the gas inlet  12 . The number of gas injection plates,  41 ,  42  and  43 , may vary based on demands. Thus, the gases are uniformly injected and provided to the upper electrode  31 . Then, the gases are spread into the reaction region between the upper electrode  31  and the lower electrode  21  through the plurality of holes  32  of the upper electrode  31 .  
         [0017]     Moreover, the chamber  10  includes lower and upper shields  23  and  33  formed around the lower electrode  21  and the upper electrode  31 , respectively. A part of the upper shield  33  extends into the reaction region, so that a density of plasma increases in an area corresponding to the substrate  22 .  
         [0018]     However, it becomes difficult for the dry etch apparatus of the related art to uniformly spread gases onto the entire surface of the substrate as the size of the substrate increases. In addition, the dry etch apparatus according to the relate art does not provide different etch rates for a center portion and an edge portion of the substrate even when a layer should be differently etched across the surface of the substrate. For example, an active layer is further etched in the edge portion of the substrate, while a passivation layer is further etched in the center portion of the substrate.  
       SUMMARY OF THE INVENTION  
       [0019]     Accordingly, the present invention is directed to an apparatus for manufacturing a liquid crystal display device and a liquid crystal display device manufactured using the same that substantially obviate one or more of the problems due to limitations and disadvantages of the related art.  
         [0020]     An object of the present invention is to provide an apparatus for manufacturing a liquid crystal display device that selectively treats regions of a substrate and a liquid crystal display device manufactured using the same.  
         [0021]     Another object of the present invention is to provide an apparatus for manufacturing a liquid crystal display device that selectively provides gases across the surface of a substrate and deposits/etches a thin film at a varying rate across the surface of the substrate according to positions, and a liquid crystal display device manufactured using the same.  
         [0022]     Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.  
         [0023]     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, an apparatus for forming a thin film on a substrate includes a chamber having a gas inlet, an upper electrode in the chamber, the upper electrode having a plurality of nozzles, a lower electrode in the chamber for supporting the substrate thereon, the lower electrode being spaced apart from the upper electrode, and a selective injection plate above the upper electrode, the selective injection plate including a selective injection valve for selectively concentrating a gas supplied through the gas inlet onto a portion of the upper electrode.  
         [0024]     In another aspect, a liquid crystal display device includes a first substrate, a second substrate, one of the first and second substrates having a thin film formed by an apparatus for forming a thin film on a substrate includes a chamber having a gas inlet, an upper electrode in the chamber, the upper electrode having a plurality of nozzles, a lower electrode in the chamber for supporting the substrate thereon, the lower electrode being spaced apart from the upper electrode, and a selective injection plate above the upper electrode, the selective injection plate including a selective injection valve for selectively concentrating a gas supplied through the gas inlet onto a portion of the upper electrode, and a liquid crystal layer between the first and second substrates.  
         [0025]     In yet another aspect, a method for forming a thin film on a substrate includes supplying a gas into a chamber, selectively moving a selective injection valve of a selective injection plate in the chamber, channeling the gas through the selective injection plate, selectively concentrating the gas onto a portion of an upper electrode inside the chamber using the selective injection valve, and injecting the gas across the substrate supported by a lower electrode at a varying gas injection rate across a surface of the substrate, the upper and lower electrodes spaced apart from each other.  
         [0026]     In another aspect, a liquid crystal display device includes a first substrate, a second substrate, one of the first and second substrates having a thin film formed by a method for forming a thin film on a substrate includes supplying a gas into a chamber, selectively moving a selective injection valve of a selective injection plate in the chamber, channeling the gas through the selective injection plate, selectively concentrating the gas onto a portion of an upper electrode inside the chamber using the selective injection valve, and injecting the gas across the substrate supported by a lower electrode at a varying gas injection rate across a surface of the substrate, the upper and lower electrodes spaced apart from each other, and a liquid crystal layer between the first and second substrates.  
         [0027]     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:  
         [0029]      FIG. 1  is a cross-sectional view illustrating a dry etching apparatus for manufacturing a liquid crystal display device according to the related art;  
         [0030]      FIG. 2  is a plan view illustrating an upper electrode of the dry etching apparatus shown in  FIG. 1 ;  
         [0031]      FIG. 3  is a cross-sectional schematic view illustrating an apparatus for manufacturing a liquid crystal display device according to an embodiment of the present invention; and  
         [0032]      FIGS. 4A and 4B  are cross-sectional views illustrating an injection plate of an apparatus according to an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.  
         [0034]      FIG. 3  is a cross-sectional schematic view illustrating an apparatus for manufacturing a liquid crystal display device according to an embodiment of the present invention. In  FIG. 3 , an apparatus  50  includes a chamber  52 . A gas inlet  54  is formed in an upper side of the chamber  52 , and a gas outlet  56  is formed in a lower side of the chamber  52 . Gases are injected into the chamber  52  through the gas inlet  54  from a gas-storing unit (not shown) and exhausted from the chamber  52  through the gas outlet  56 . The apparatus  50  may be a dry etching apparatus or a plasma etching apparatus. Further, the apparatus  50  may be a chemical vapor deposition (CVD) apparatus or a plasma enhanced chemical vapor deposition (PECVD) apparatus.  
         [0035]     In addition, the chamber  52  includes a lower electrode  62  and an upper electrode  58  spaced apart from each other. A substrate  64  is loaded on the lower electrode  62  inside the chamber  52 , and the substrate  64 , for example, may include a thin film to be patterned by an etching process. In particular, the lower electrode  62  is connected to an outer power supplier  63 , which may be located outside the chamber  52  and may apply a radio frequency (RF) power to the lower electrode  62 .  
         [0036]     Further, the space between the lower electrode  62  and the upper electrode  58  often is referred to a reaction region. In particular, the upper electrode  58  is grounded and includes a plurality of injection nozzles  60  for injecting the gases provided through the gas inlet  54 . The injection nozzles  60  may be arranged in a matrix manner across the upper electrode  58 .  
         [0037]     The chamber  52  further includes gas injection plates,  65 ,  66  and  67 , disposed over the upper electrode  58 . In particular, each of the gas injection plates,  65 ,  66  and  67 , includes a plurality of nozzles (not shown) for evenly distributing the gases injected through the gas inlet  54 . The number of gas injection plates,  65 ,  66  and  67 , may vary based on demands, such that the apparatus  50  may have at least one gas injection plate.  
         [0038]     Moreover, the chamber  52  includes a selective injection plate  70  disposed between the upper electrode  58  and the gas injection plates,  65 ,  66 , and  67 . In particular, the selective injection plate  70  controls the gas distribution across the upper electrode  58  by using a selective injection valve  76 . Accordingly, the gases injected through the gas inlet  54  are selectively spread across the substrate  64  through the nozzles of the gas injection plates  65 ,  66  and  67 , through the selective injection valve  76 , and then through the injection nozzles  60  of the upper electrode  58 .  
         [0039]      FIGS. 4A and 4B  are cross-sectional views illustrating an injection plate of an apparatus according to an embodiment of the present invention. In  FIGS. 4A and 4B , a selective injection plate  70  includes at lease one first injection hole  72  and at least one second injection hole  74 . The first injection hole  72  may correspond to a center portion of an upper electrode  58  (shown in  FIG. 3 ) for concentrating gases onto a center portion of a substrate  64  (shown in  FIG. 3 ). In addition, the second injection hole  74  may correspond to an edge portion of the upper electrode  58  (shown in  FIG. 3 ) for concentrating gases onto an edge portion of the substrate  64  (shown in  FIG. 3 ).  
         [0040]     The selective injection plate  70  further includes a selective injection valve  76  in the center of the selective injection plate  70  for selectively injecting gases through either the first injection hole  72  or the second injection hole  74 . The selective injection valve  76  may independently move up and down controlled by a control system outside the chamber  52 . In particular, the selective injection valve  76  includes a first hole  76   a  and a second hole  76   b.  The first hole  76   a  and the second hole  76   b  may connect to one another. The first hole  76   a  also may have an opening at an upper surface of the selective injection valve  76 , and the second hole  76   b  may have an opening at a side surface of the selective injection valve  76 . For example, the first hole  76   a  and the second hole  76   b  may be connected to one another and may form an inverted “T” shape.  
         [0041]     As shown in  FIG. 4A , when the selective injection valve  76  is moved to a lower position, the second hole  76   b  may be connected to the first injection hole  72  for injecting gases through the first injection hole  72 . Accordingly, when the second hole  76   b  of the selective injection valve  76  corresponds to the first injection hole  72 , gases supplied through the gas injection plates  65 ,  66  and  67  (shown in  FIG. 3 ) pass through the first hole  76   a,  the second hole  76   b  and then the first injection hole  72  to the center portion of the upper electrode  58  (shown in  FIG. 3 ).  
         [0042]     As shown in  FIG. 4B , when the selective injection valve  76  is moved to an upper position, the second hole  76   b  may be connected to the second injection hole  74  for injecting gases through the second injection hole  74 . Accordingly, when the second hole  76   b  of the selective injection valve  76  corresponds to the second injection hole  74 , gases supplied through the gas injection plates  65 ,  66  and  67  (shown in  FIG. 3 ) pass through the first hole  76   a,  the second hole  76   b  and then the second injection hole  74  to the edge portion of the upper electrode  58  (shown in  FIG. 3 ).  
         [0043]     Further, although not shown, a solenoid may be equipped for selectively moving the selective injection valve  76  up and down. Therefore, the selective injection valve  76  moves according to control signals applied to the solenoid from an outer system (not shown).  
         [0044]     Moreover, although not shown, the selective injection valve  76  may include more than first and second injection holes and may be moved to a position other than the upper and lower positions, thereby more minutely controlling the gases distribution. For example, the selective injection valve  76  may include first, second and third injections holes for respectively concentrating gases onto the center, the middle and the edge portion of the upper electrode  58  (shown in  FIG. 3 ). As a result, by moving the selective injection valve  76 , gases are selectively injected through either the first injection hole  72  or the second injection hole  74 . Thus, the gas injection rate may be varying.  
         [0045]     Accordingly, the gases injected through the gas inlet  54  (shown in  FIG. 3 ) are selectively spread across the substrate  64  (shown in  FIG. 3 ) through the nozzles of the gas injection plates  65 ,  66  and  67  (shown in  FIG. 3 ), through the first and second holes  76   a  and  76   b  of the selective injection valve  76 , one of the first and second injection holes  72  and  74 , and then through the injection nozzles  60  of the upper electrode  58 .  
         [0046]     Therefore, the apparatus according to an embodiment of the present invention includes a selective injection plate for selectively concentrating gases onto at least a center portion and an edge portion of an upper electrode. Thus, the apparatus according to an embodiment of the present invention selectively treats regions of a substrate and selectively controls a gas injection rate across the surface of the substrate, thereby depositing/etching a thin film across the surface of the substrate at variable rates.  
         [0047]     Although not shown, the apparatus according to an embodiment of the present invention may be used for depositing/etching a thin film on any type of substrate, for example, an insulative substrate or a semiconductor substrate.  
         [0048]     It will be apparent to those skilled in the art that various modifications and variations can be made in the apparatus for manufacturing a liquid crystal display device and a liquid crystal display device manufactured using the same of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.