Abstract:
An apparatus for depositing atomic layers coats first and second reaction layers alternately on a substrate by repeating injection of source precursor and purge gas from a showerhead with the showerhead moving forward and injection of reactant precursor and the purge gas from the showerhead with the showerhead moving backward. The precursors and purge gas injected are exhausted in real time through the showerhead. Mixing of the source and reactant precursors is prevented by the alternate injections of the source and reactant precursors. Throughput is improved by the simultaneous injections of the precursor and the purge gas. By minimizing a moving distance of the showerhead, a footprint is reduced and the apparatus can be used for large size substrates. It is also possible to deposit the atomic layers selectively on a specific selected region.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is entitled to the benefit of KR Patent Application Ser. Nos. 10-2012-0065954 filed on Jun. 20, 2012, 10-2012-0068196 filed on Jun. 25, 2012, 10-2012-0074317 filed on Jul. 9, 2012, and 10-2012-0080232 filed on Jul. 23, 2012, which are all incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The invention relates generally to a thin film deposition apparatus, and more particularly to an apparatus and a method for depositing atomic layers on semiconductor substrates. 
       BACKGROUND OF THE INVENTION 
       [0003]    Atomic layer deposition is widely used to deposit thin films on semiconductor wafers and its application is extended to deposit thin films on CIGS solar cells, Si solar cells and OLED displays. Typical atomic layer deposition process consists of the following four steps. 
         [0004]    At the first step, source precursor such as TMA trimethyl-aluminum is injected to the substrate. The source precursor reacts with the surface of the substrate and coats the surface with a first reaction layer. 
         [0005]    At the second step, which is a purge step, the source precursor which is adsorbed physically on the surface of the substrate is removed by injecting inert gas such as nitrogen to the substrate. 
         [0006]    At the third step, reactant precursor such as H 2 O is injected to the substrate. The reactant precursor reacts with the first reaction layer and coats the substrate with a second reaction layer. 
         [0007]    At the fourth step, which is the purge step, the reactant precursor which is adsorbed physically on the surface of the substrate is removed by injecting the inert gas. Through the cycle, a single layer of thin film consisting of the first and second reaction layers, for example Al 2 O 3  thin film, is deposited on the substrate. To get a thin film with a desired thickness the cycle is repeated. 
         [0008]    Deposition speed of the thin film by the atomic layer deposition process is determined by the time required to complete the cycle of the four steps. Therefore the atomic layer deposition has a disadvantage that the deposition speed is slow because the supplies of the source precursor, the purge gas, the reactant precursor and the purge gas must be sequential. 
         [0009]    Referring to  FIGS. 1 and 2 , another ALD (atomic layer deposition) method, so called space-divided ALD, is described.  FIGS. 1 and 2  are side and top views of an ALD apparatus according to the space-divided ALD, respectively. In the space-divided ALD, the second, first and second reaction layers are sequentially coated on the substrate  50  by moving the substrate  50  through a shower head  20  having a hole for injecting the reactant precursor  21 , a hole for exhaust  22 , a hole for injecting the purge gas  23 , a hole for exhaust  24 , a hole for injecting the source precursor  25 , a hole for exhaust  26 , a hole for injecting the purge gas  27 , a hole for exhaust  28 , and a hole for injecting the reactant precursor  29 . 
         [0010]    The source precursor injected from the hole  25  is exhausted through its neighboring holes for exhaust  24  and  26 . The reactant precursor injected from the holes  21  and  29  is exhausted through the respective neighboring holes  22  and  28 . The purge gas injected from the hole  23  is exhausted through its neighboring holes for exhaust  22  and  24 . The purge gas injected from the hole  27  is exhausted through its neighboring holes for exhaust  27  and  94 . 
         [0011]    The space-divided ALD has problems that a moving distance of the substrate or the showerhead is long and a footprint of the apparatus is large because the substrate  50  must be moved completely to the opposite side of the showerhead  20  through the showerhead  20  as shown in  FIG. 2  in order to get a uniform film thicknesses on both of the edge region  50   a  and the central region  50   b  of the substrate  50 . 
         [0012]    The space-divided ALD also has a problem that the substrate must move back and forth  52  at high speed a distance equal to the widths of the substrate  52   w  and the showerhead  20   w  in order to deposit the thin film at high speed. 
         [0013]    This problem becomes more remarkable as the widths of the substrate  50   w  and the showerhead  20   w  become greater. For example, a minimum moving distance for CIGS solar cell substrate is over 600 mm as its size is 1200 mm×600 mm. For another example, a minimum moving distance for 5.5 generation OLED display substrate is over 1300 mm as its size is 1500 mm×1300 mm. 
         [0014]    In addition, the moving speed of the substrate  50  and the design of the showerhead  20  can be also limited because particles can be generated if the source and reactant precursors are mixed during the high speed moving. 
         [0015]    In order to prevent mixing of the source and reactant precursors, the showerhead  20  must be disposed as close as possible to the substrate. For example, the gap between the substrate  50  and the showerhead  20  must be less than 1 mm. 
         [0016]    When it needs to deposit the atomic layers on a selected region of the substrate, the conventional ALD uses a shadow mask. By placing the shadow mask on the substrate the atomic layers are deposited only on the regions which are not shadowed by the shadow mask. The shadow mask must be replaced periodically because the atomic layers are also deposited on the shadow mask. It is also inconvenient to load and unload the shadow mask to and from the surface of the substrate whenever the substrates are changed. 
         [0017]    As described above, ALD requires an apparatus and methods that are designed to provide a short cycle time and a short back and forth moving distance of the substrate or the showerhead. ALD requires an apparatus and methods that are designed such that the source and reactant precursors are not mixed and therefore particles are not generated. 
         [0018]    ALD requires also an apparatus and methods that are designed to deposit the atomic layers on selected region of the substrate without using the shadow mask. 
       SUMMARY OF THE INVENTION 
       [0019]    An atomic layer deposition apparatus and a method according to an embodiment of the invention provide the short cycle time and the short moving distance of the substrate or the showerhead. The atomic layer deposition apparatus and method according to an embodiment of the invention prevent of mixing of the source and reactant precursors and the particle generation. 
         [0020]    In addition, an atomic layer deposition apparatus and method according to an embodiment of the invention provide selective deposition of the atomic layers on the selected region of the substrate without using the shadow mask. 
         [0021]    An apparatus for depositing atomic layers according to an embodiment of the invention injects source precursor to the whole surface of the substrate with the substrate or the showerhead moving forward and reactant precursor to the whole surface of the substrate with the substrate or the showerhead moving backward. The apparatus can prevent mixing of the source and reactant precursors as the source and reactant precursors are injected with the time interval. 
         [0022]    An apparatus for depositing atomic layers according to an embodiment of the invention injects purge gas through the showerhead simultaneously when the source and reactant precursors are injected to the substrate. The apparatus exhausts the purge gas, the source precursor and the reactant precursor through the showerhead immediately after they are injected. The apparatus can provide a reduced cycle time. 
         [0023]    An apparatus for depositing atomic layers according to an embodiment of the invention has a moving distance of the showerhead or the substrate as short as a pitch of injection units. For example, the pitch is between 30 mm to 100 mm. Therefore the apparatus can provide a greater throughput and a reduced footprint. 
         [0024]    An apparatus for depositing atomic layers according to an embodiment of the invention may deposit the atomic layers selectively on a selected region of the substrate without using a shadow mask by controlling the moving distance of the showerhead or the substrate. 
         [0025]    An apparatus for depositing atomic layers according to an embodiment of the invention comprises a showerhead disposed about the substrate and having an injection surface comprising a hole for injecting first materials, a hole for injecting second materials, a hole for injecting purge gas and a hole for exhaust, a moving mechanism configured to move the substrate support or the showerhead back and forth between first and second locations along a first direction, and a control mechanism to control supplies of the first materials injected through the hole for injecting the first materials, the second materials injected through the hole for injecting the second materials, the purge gas injected through the hole for injecting purge gas and the exhaust supplied to the substrate through the hole for exhaust. The control mechanism is configured not to supply the first and second materials to the substrate at the same time and further configured to supply the purge gas and the exhaust to the substrate while the first and second materials are supplied to the substrate through the respective holes for injecting the first and second materials. 
         [0026]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the injection surface comprises at least one injection unit which is disposed along the first direction and extends to a direction perpendicular to the first direction. Each of the injection unit of the apparatus comprises a hole array for injecting the first materials, a hole array for injecting the second materials and at least one hole array for the exhaust. 
         [0027]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the at least one hole array for the exhaust comprises first and second hole arrays for the exhaust. The apparatus is further configured such that the hole array for injecting the first materials is disposed between the first and second hole arrays for the exhaust and the hole array for injecting the second materials is disposed between the hole array for injecting the first materials and the second hole array for the exhaust. 
         [0028]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the first and second materials are exhausted through the first and second hole arrays for the exhaust, respectively. 
         [0029]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the injection unit comprises a first hole array for injecting the purge gas which is disposed between the hole arrays for injecting the first and second materials. 
         [0030]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that a third hole array for the exhaust is disposed between the hole array for injecting the first materials and the first hole array for injecting the purge gas. The apparatus is further configured such that a fourth hole array for the exhaust is disposed between the hole array for injecting the second materials and the first hole array for injecting the purge gas. 
         [0031]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that a first hole array for injecting the purge gas is disposed between the hole array for injecting the first materials and the first hole array for the exhaust, a second hole array for injecting the purge gas is disposed between the hole array for injecting the first materials and the third hole array for the exhaust, a third hole array for injecting the purge gas is disposed between the hole array for injecting the second materials and a fourth hole array for the exhaust, and a fourth hole array for injecting the purge gas is disposed between the hole array for injecting the second materials and the second hole array for the exhaust. 
         [0032]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the first materials is exhausted through the first and third hole arrays for the exhaust and the second materials is exhausted through the second and fourth hole arrays for the exhaust. 
         [0033]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that a hole array for injecting the purge gas is disposed between the at least one injection units. 
         [0034]    An apparatus for depositing atomic layers according to an embodiment of the invention may be configured such that the injection surface comprises a purge gas injection surface extending from an end of the injection surface to the opposite end of the injection surface along the first direction. The purge gas injection surface of the apparatus does not comprise holes for injecting the first and second materials. The purge gas injection surface may comprise a hole for injecting the purge gas. The purge gas injection surface may comprise a hole for the exhaust. The purge gas injection surface may not comprise any holes for the purge gas and the exhaust. The apparatus does not deposit atomic layers on a surface of the substrate corresponding to the purge gas injection surface. 
         [0035]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that both ends of the injection surface have arc shapes in case that the substrate is circular. 
         [0036]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the moving mechanism comprises a guide block coupled to the showerhead and a track coupled to a showerhead support configured to support the showerhead. The guide block is slidibly coupled to the track such that the showerhead moves back and forth on the track. 
         [0037]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the moving mechanism comprises a rotator of a linear motor coupled to the showerhead and a stator of the linear motor coupled to the showerhead support. 
         [0038]    An apparatus for depositing atomic layers according to an embodiment of the invention comprises a hole for injecting clean or inert gas towards the showerhead and the substrate support. The hole is disposed under the showerhead support. 
         [0039]    An apparatus for depositing atomic layers according to an embodiment of the invention comprises a first chamber coupled to the showerhead support and configured to approach to the showerhead and the substrate support through an opening of the first chamber such that the first chamber surrounds the showerhead and the showerhead support. 
         [0040]    An apparatus for depositing atomic layers according to an embodiment of the invention comprises a hole for exhaust, which is disposed about the substrate support and a side wall of the first chamber. 
         [0041]    An apparatus for depositing atomic layers according to an embodiment of the invention comprises a second chamber which is configured to isolate the showerhead support, the showerhead, the substrate support and the hole for exhaust from the environment. 
         [0042]    An apparatus for depositing atomic layers according to an embodiment of the invention comprises a first frame, a second frame, shafts whose one ends are coupled to the first frame and other ends are coupled to the second frame, a showerhead support movably coupled to the shafts, and a moving mechanism configured to move the showerhead support between the first and second frames. 
         [0043]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the at least one injection units are disposed at the same interval X along the first direction. The apparatus is further configured such that the hole array for injecting the first materials of the at least one injection units is disposed a certain distance X1 away from the hole array for injecting the second materials of the at least one injection unit. 
         [0044]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the at least one injection unit comprises a first injection unit disposed at a first end of the injection surface and a second injection unit disposed at an opposite end of the first end of the injection surface. The apparatus is further configured such that, when the showerhead is located at the first location, a first end of the substrate placed on the substrate support is located between a hole array  80   b  of the first injection unit for injecting the second materials and a hole array  80   a  of a third injection unit, which is disposed next to the first injection unit, for injecting the first materials, and a second end of the substrate which is opposite to the first end of the substrate is located between a hole array  80   b  of the second injection unit for injecting the second materials and a location which is X-X1 distance away along the first direction from the hole array  80   b  of the second injection unit for injecting the second materials. The first end of the substrate may be aligned to the hole array  80   b  of the first injection unit for injecting the second materials, and the second end of the substrate may be aligned to a location X-X1 distance away along the first direction from the hole array  80   b  of the second injection unit for injecting the second materials. 
         [0045]    The apparatus is further configured such that, when the showerhead is located at the second location, the first end of the substrate is located between the hole array  80   a  of the first injection unit for injecting the first materials and a location which is X-X1 distance away along a reverse direction of the first direction from the hole array  80   a  of the first injection unit for injecting the first materials, and the second end of the substrate is located between the hole array  80   a  of the second injection unit for injecting the first materials and the hole array  80   b  of a fourth injection unit, which is disposed next to the second injection unit, for injecting the second materials. The first end of the substrate may be aligned to a location which is X-X1 distance away along the reverse direction of the first direction from the hole array  80   a  of the first injection unit for injecting the first materials, and the second end of the substrate may be aligned to the hole array  80   a  of the second injection unit for injecting the first materials. 
         [0046]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the at least one injection units comprise a first injection unit disposed at a first end of the injection surface and a second injection unit disposed at an opposite end of the first end. The apparatus is further configured such that the showerhead further comprises an injection unit for injecting the first materials, which is disposed next to the second injection unit. The apparatus is also configured such that the injection unit for injecting the first materials comprises a hole array for injecting the first materials and hole arrays for the exhaust. The hole array for injecting the first materials is disposed at a location which is a certain distance X away from the hole array  80   a  of the second injection unit for injecting the first materials. The hole arrays for the exhaust are disposed before and after the hole array for injecting the first materials. 
         [0047]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that, when the showerhead is located at the first location, the first end of the substrate placed on the substrate support is located between the hole array  80   b  of the first injection unit for injecting the second materials and a hole array  80   a  of a third injection unit, which is disposed next to the first injection unit, for injecting the first materials, and the second end of the substrate which is opposite to the first end of the substrate is located between a hole array  80   a  of the first injection unit for injecting the first materials and a location which is X1 distance away along the first direction from the hole array  80   a  of the first injection unit for injecting the first materials. The first end of the substrate may be aligned to the hole array  80   b  of the first injection unit for injecting the second materials and the second end of the substrate may be aligned to a location which is X1 distance away along the first direction from the hole array  80   a  of the first injection unit for injecting the first materials. 
         [0048]    The apparatus is further configured such that, when the showerhead is located at the second location, the first end of the substrate is located between the hole array  80   a  of the first injection unit for injecting the first materials and a location which is X-X1 distance away along the reverse direction of the first direction from the hole array  80   a  of the first injection unit for injecting the first materials, and the second end of the substrate is located between the hole array  80   a  of the second injection unit for injecting the first materials and the hole array  80   b  of the second injection unit for injecting the second materials. The first end of the substrate may be aligned to a location which is X-X1 distance away along the reverse direction of the first direction from the hole array  80   a  of the first injection unit for injecting the first materials, and the second end of the substrate may be aligned to the hole array  80   b  of the second injection unit for injecting the second materials. 
         [0049]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the moving mechanism can pivot the showerhead between first and second angular locations about a first axis instead of moving the showerhead back and forth linearly. 
         [0050]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the showerhead which can be pivoted about the first axis by the moving mechanism comprises a single injection unit. 
         [0051]    An apparatus for depositing atomic layers according to an embodiment of the invention is configured such that the moving mechanism pivots the showerhead between the first and second angular locations about the first axis and the first and second angular axes correspond to the first and second locations respectively. 
         [0052]    A method for depositing atomic layers according to an embodiment of the invention comprises a disposing step to dispose a substrate on a substrate support; a disposing step to dispose about the substrate a showerhead having an injection surface which comprises a hole for injecting first materials, a hole for injecting second materials which reacts with the first materials to form an atomic layer, a hole for injecting purge gas and a hole for exhaust pump; a first moving step to move the substrate support or the showerhead from a first location to a second location along a first direction; an injecting and exhausting step to inject the first materials and the purge gas to the substrate through the hole for injecting the first materials and the hole for injecting the purge gas respectively and to exhaust the first materials and the purge gas through the hole for exhaust during the first moving step; a second moving step to move the substrate support or the showerhead from the second location to the first location along a reverse direction of the first direction; and an injecting and exhausting step to inject the second materials and the purge gas to the substrate through the hole for injecting the second materials and the hole for injecting the purge gas respectively and to exhaust the second materials and the purge gas through the hole for exhaust during the second moving step. The method does not inject the first and second materials during the second and first moving steps, respectively. 
         [0053]    A method for depositing atomic layers according to an embodiment of the invention uses the injection surface which comprises at least one injection unit that is disposed along the first direction and extends to a direction perpendicular to the first direction. The method uses the injection unit, each of which comprises a hole array for injecting the first materials, a hole array for injecting the second materials, a hole array for injecting the purge gas and at least one hole array for exhaust. 
         [0054]    A method for depositing atomic layers according to an embodiment of the invention does not inject the first and second materials while the showerhead is moving from the first location to a third location during the first moving step. The method does not inject the second materials but inject the first materials while the showerhead is moving from the third location to the second location. 
         [0055]    A method for depositing atomic layers according to an embodiment of the invention has the third location between the first and second locations, which is closer to or coincides with the first location. 
         [0056]    A method for depositing atomic layers according to an embodiment of the invention does not inject the first and second materials while the showerhead is moving from the second location to a fourth location during the second moving step. The method does not inject the first materials but inject the second materials while the showerhead is moving from the fourth location to the first location. 
         [0057]    A method for depositing atomic layers according to an embodiment of the invention has the fourth location between the first and second locations, which is closer to or coincides with the second location. 
         [0058]    A method for depositing atomic according to an embodiment of the invention may use different moving speeds of the showerhead during the first and second moving steps. For example, the method may use the greater moving speed during the first moving step than during the second moving step. 
         [0059]    A method for depositing atomic layers according to an embodiment of the invention further comprises a first purge step after the first moving step is completed and before the second moving step begins. During the first purge step the method does not inject the first and second materials but injects and exhausts the purge gas. 
         [0060]    A method for depositing atomic layers according to an embodiment of the invention further comprises a second purge step after the second moving step is completed and before the first moving step begins. During the second purge step the method does not inject the first and second materials but injects and exhausts the purge gas. 
         [0061]    A method for depositing atomic layers according to an embodiment of the invention may use different times to purge during the first and second purge steps. 
         [0062]    A method for depositing atomic layers according to an embodiment of the invention uses a distance, which is similar to the distance between holes for injecting the first materials of the adjacent injection units, as a distance between the first and second locations. 
         [0063]    A method for depositing atomic layers according to an embodiment of the invention uses a distance, which is smaller than the distance between the holes for injecting the first materials of the adjacent injection units, as the distance between the first and second locations. The method does not deposit atomic layers on the whole surface of the substrate but on a specific. 
         [0064]    A method for depositing atomic layers according to an embodiment of the invention exhausts the first and second materials through first and second holes of the at least one holes for exhaust, respectively. 
         [0065]    A method for depositing atomic layers according to an embodiment of the invention injects the purge gas through the hole for injecting the second materials during the first moving step and injects the purge gas through the hole for injecting the first materials during the second moving step. 
         [0066]    A method for depositing atomic layers according to an embodiment of the invention, a method comprises the disposing step to dispose the substrate on the substrate support; the disposing step to dispose about the substrate the showerhead having the injection surface comprising the hole for injecting first materials, the hole for injecting the second materials which reacts with the first materials to form the atomic layer, the hole for injecting the purge gas and the hole for exhaust; the first moving step to move the substrate support or the showerhead from the first location to the second location along the first direction; the injecting and exhausting step to inject the first materials and the purge gas to the substrate through the hole for injecting the first materials and the hole for injecting the purge gas respectively and to exhaust the first materials and the purge gas through the hole for exhaust during the first moving step; the second moving step to move the substrate support or the showerhead from the second location to the first location along the reverse direction of the first direction; an injecting and exhausting step to inject and exhaust the purge gas during the second moving step; a third moving step to move the substrate support or the showerhead from the first location to the second location along the first direction; and an injecting and exhausting step to inject the second materials and the purge gas to the substrate through the hole for injecting the second materials and the hole for injecting the purge gas respectively and to exhaust the second materials and the purge gas through the hole for exhaust during the third moving step. The method does not inject the second materials during the first and second moving steps and the first materials during the second and third moving steps. 
         [0067]    A method for depositing atomic layers according to an embodiment of the invention uses the injection surface which comprise the at least one injection unit that is disposed along the first direction and extends to the direction perpendicular to the first direction. The method uses the injection unit, each of which comprises the hole array for injecting the first materials, the hole array for injecting the second materials, the hole array for injecting the purge gas and the at least one hole array for exhaust. 
         [0068]    A method for depositing atomic according to an embodiment of the invention may use different moving speeds of the showerhead during the first, second and third moving steps. 
         [0069]    A method for depositing atomic layers according to an embodiment of the invention uses the distance, which is similar to the distance between the holes for injecting the first materials of the adjacent injection units as the distance between the first and second locations. 
         [0070]    A method for depositing atomic layers according to an embodiment of the invention uses the distance, which is smaller than the distance between the holes for injecting the first materials of the adjacent injection units, as the distance between the first and second locations. The method does not deposit atomic layers on the whole surface of the substrate but on a specific region of the substrate. 
         [0071]    A method for depositing atomic layers according to an embodiment of the invention exhausts the first and second materials through the first and second holes of the at least one holes for exhaust, respectively. 
         [0072]    A method for depositing atomic layers according to an embodiment of the invention injects the purge gas through the hole for injecting the second materials during the first moving step and injects the purge gas through the hole for injecting the first materials during the third moving step. 
         [0073]    A method for depositing atomic layers according to an embodiment of the invention exhausts the purge gas through the hole for exhaust during the second moving step. 
         [0074]    A method for depositing atomic layers according to an embodiment of the invention injects the purge gas through the holes for injecting the first and second materials during the second moving step. 
         [0075]    Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrated by way of example of the principles of the invention. 
       ADVANTAGE OF THE INVENTION 
       [0076]    According to the invention, the apparatus and the method provide a reduced cycle time, a short reciprocating distance of the substrate or the showerhead, and a reduced footprint of the apparatus. According to the invention the source and reactant precursors are not mixed and therefore particle generation is controlled. According to the invention, the apparatus and the method provide selective atomic layer deposition on a selected region of the substrate without the shadow mask. 
         [0077]    According to the invention, the apparatus and the method provide selective deposition of the atomic layers on the selected region of the substrate without using the shadow mask. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0078]      FIG. 1  is a side view of an atomic layer deposition apparatus according to a conventional technology. 
           [0079]      FIG. 2  is a top view of the atomic layer deposition apparatus according to the conventional technology. 
           [0080]      FIG. 3  is a side view of an atomic layer deposition apparatus according to an embodiment of an invention. 
           [0081]      FIG. 4  is a front view of the atomic layer deposition apparatus according to an embodiment of the invention. 
           [0082]      FIG. 5  is a front view of the atomic layer deposition apparatus according to an embodiment of the invention. 
           [0083]      FIG. 6  is a front view of the atomic layer deposition apparatus according to an embodiment of the invention. 
           [0084]      FIG. 7  is a front view of the atomic layer deposition apparatus according to an embodiment of the invention. 
           [0085]      FIG. 8  is a bottom view of a showerhead according to an embodiment of the invention. 
           [0086]      FIG. 9  is a cross sectional view of the showerhead illustrated in  FIG. 8 . 
           [0087]      FIG. 10  is a cross sectional view of the showerhead illustrated in  FIG. 8 . 
           [0088]      FIG. 11  is a bottom view of the showerhead according to an embodiment of the invention. 
           [0089]      FIG. 12  is a bottom view of an injection unit according to an embodiment of the invention. 
           [0090]      FIG. 13  is a bottom view of the showerhead according to an embodiment of the invention. 
           [0091]      FIG. 14  is a bottom view of the injection unit according to an embodiment of the invention. 
           [0092]      FIG. 15  is a top view of the substrate support according to an embodiment of the invention. 
           [0093]      FIG. 16  is a top view of the substrate support and the showerhead according to an embodiment of the invention. 
           [0094]      FIG. 17  is a three dimensional view of a protecting chamber according to an embodiment of the invention. 
           [0095]      FIG. 18  is a cross sectional view of the atomic layer deposition apparatus according to an embodiment of the invention. 
           [0096]      FIG. 19  is a bottom view of the showerhead according to an embodiment of the invention. 
           [0097]      FIG. 20  is a top of the atomic layer deposition apparatus according to an embodiment of the invention. 
           [0098]      FIG. 21  is a cross sectional view of the atomic layer deposition apparatus according to an embodiment of the invention. 
           [0099]      FIG. 22  is a bottom view of the showerhead according to an embodiment of the invention. 
           [0100]      FIG. 23  is a bottom view of the showerhead according to an embodiment of the invention. 
           [0101]      FIG. 24  is a top view of the substrate comprising the atomic layers deposited by an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0102]    With reference to the figures attached, embodiments according to the invention are described. 
         [0103]      FIGS. 3 and 4  are side and front views of an atomic layer deposition apparatus according to an embodiment of the invention. Referring to  FIGS. 3 and 4 , the ALD apparatus  100  may comprise a lower frame  102 , an upper frame  104 , shafts  103 , a substrate support  110 , a showerhead support  106 , a showerhead  120 , a showerhead reciprocating mechanism  121 , a showerhead vertical moving mechanism  140  and a gas supply control system  170 . To heat the substrate support  100  the ALD  100  may comprise a heating element not illustrated) such as a lamp heater disposed below the substrate support  110  or a heating wire embedded in the substrate support  110 . 
         [0104]    One ends of the shafts  103  are coupled to the lower frame  102  and the opposite ends are coupled to the upper frame  104 . The showerhead support  106  is coupled to the shafts  103  such that it moves vertically between the upper frame  104  and the substrate support  110 . 
         [0105]    The showerhead  120  is supported by the showerhead support  106  by being coupled to an overhead track  124  by guide blocks  122 . One ends of the guide blocks  122  are coupled to a top surface of the showerhead  120  and the opposite ends are movably coupled to the overhead track  124 , which is coupled to a bottom surface of the showerhead support  106 . The guide blocks  122  and the overhead track  124  are elements of the showerhead reciprocating mechanism  121 . A non-contact type magnetic levitation track can be used instead of the overhead track  124  and the guide block  122 . 
         [0106]    A linear motor can be comprised as another element of the showerhead reciprocating mechanism  121 . The linear motor consists of a rotator  130  and a stator  132 . The stator  132  is coupled to the bottom surface of the showerhead support  106  such that its has the same direction with the overhead track  124 . The rotator  130  is coupled to the top surface of the showerhead  120  such that it faces the stator  132 . A permanent magnet can be used as the rotator  130  and an electrical coil connected to a source of electricity can be used as the stator  132 . The showerhead  120  connected to the stator  130  can be moved back and forth between first and second positions along a first direction by applying attractive or repulsive force to the rotator  130  by electromagnetic force induced when the electricity flows along the coil. The first direction is the direction parallel to the substrate  50  or the substrate support  110 . 
         [0107]    The showerhead vertical moving mechanism  140  comprises a servo motor  141  coupled to the upper frame  104 , a screw  142  rotated by the servo motor  141 , and a female screw  144  whose one end is coupled to the top surface of the showerhead support  106  and other end is movably coupled to the screw  142 . The showerhead support  106  and therefore the showerhead  120  supported by the showerhead support  106  can be moved vertically by rotating the screw  142  by the servo motor  141 . 
         [0108]    The vertical location of the showerhead  120  illustrated in  FIGS. 3 and 4  is the location for loading and unloading the substrate  50 . At the loading and unloading location, a substrate transporter not illustrated can transfer the substrate with the substrate support  110  as the substrate  50  is exposed from showerhead  120 . 
         [0109]      FIG. 5  is a side view of the ALD apparatus  100  after the showerhead  120  is moved down to a deposition location. At the deposition location the showerhead  120  approaches to the substrate support  110  and the substrate  50  and surrounds the substrate  50 . When the showerhead  120  is located at the deposition location, an injection surface  120   a  of the showerhead  120  may be positioned 0.2˜3 mm apart from the surface of the substrate. According to an embodiment, the injection surface  120   a  may be located 0.1˜30 mm apart from the substrate. The distance between the injection surface  120   a  and the substrate at the deposition location may be adjusted by the showerhead vertical moving mechanism  140 . 
         [0110]    The ALD apparatus  100  when the showerhead  120  is located at first and second locations  70  and  72  is illustrated in  FIGS. 6 and 7 , respectively.  FIGS. 6 and 7  are side views of the ALD apparatus  100  when the showerhead  120  is located at the first and second locations  70  and  72  respectively. The first and second locations  70  and  72  are locations for depositing atomic layers. 
         [0111]    The ALD  100  is configured to coat the substrate  50  with a first reaction layer by injecting source precursor and purge gas at the same time while the showerhead  120  is moved from the first location  70  to the second location  72 . The ALD  100  is further configured to coat the first reaction layer with a second reaction layer by injecting reactant precursor and the purge gas at the same time while the showerhead  120  is moved from the second location  72  to the first location  70 . The showerhead  120  deposits a desired thickness or a desired number of atomic layers by reciprocating repeatedly between the first and second locations  70  and  72  and coating the surface of the substrate  50  alternately with the first and second reaction layers. The ALD apparatus  100  may be configured such that the source and reactant precursors and the purge gas which were injected to the substrate  50  are exhausted in real time through the showerhead  120 . 
         [0112]    Turning back to  FIGS. 3 and 4 , gas injection holes  150  may be disposed at a lower part of the showerhead support  106 . The gas injection holes  150  are connected to a source of inert gas such as nitrogen gas or a source of filtered-particle-free clean air. The gas injection holes  150  are configured to inject purge gas such as the inert gas or the clean air. The injected purge gas purges particles, which can be generated from the showerhead reciprocating mechanism  121  when the showerhead  120  moves back and forth, to outside of the ALD apparatus  100 . 
         [0113]    The gas supply control system  170  is configured to control supplies of the source precursor, the reactant precursor, the purge gas and the exhaust which are supplied to the showerhead  120  through respective supply conduits  162  from sources of the source precursor, the reactant precursor and the purge gas and an exhaust pump, respectively. The exhaust is used to exhaust the source precursor, the reactant precursor and the purge gas. It is noted that the gas supply control system  170  is configured not to supply the source and reactant precursors simultaneously. The gas supply control system  170  may be configured to supply the source precursor and the purge gas simultaneously, the reactant precursor and the purge gas simultaneously, or only the purge gas. The gas supply control system  170  may be configured to supply the exhaust to the showerhead  120  while the source and reactant precursors and the purge gas are supplied. Even though a single conduit  162  is illustrated in  FIGS. 3 and 4 , respective conduits are connected to the showerhead to supply the source precursor, the reactant precursor, the purge gas and the exhaust separately. 
         [0114]    Flexible stainless steel hoses such as FM series of Swagelok Company may be used as the conduits for the source and reactant precursors. Alternately tubes consisting of a stainless steel liner wrapped by a heat conducing plastic materials may be used. 
         [0115]    A conduit to supply cooling water to cool down the showerhead  120  may be embedded in the showerhead  120 . The conduit to supply the cooling water is connected to a source of the cooling water not illustrated. The cooling water controls the temperature of the showerhead  120  by circulating the source of the cooling water and the showerhead  120 . 
         [0116]    Referring to  FIGS. 8 ,  9  and  10 , the showerhead  120  is described.  FIG. 8  is a bottom view of the showerhead  120  and  FIGS. 9 and 10  are cross sections of  300   a  and  300   b , respectively, illustrated in  FIG. 8 . The showerhead  120  comprises first, second, third and fourth inner surfaces  122   a ˜ 122   d , first, second, third and fourth outer surfaces  123   a ˜ 123   d , and a peripheral bottom surface  120   b . The first, second, third and fourth inner surfaces  122   a ˜ 122   d  forms an inner sidewall of a chamber of the showerhead and the first, second, third and fourth outer surfaces  123   a ˜ 123   d  forms an outer sidewall of the showerhead  120 . The peripheral bottom surface  120   a  is the surface extended from the injection surface  120   a.    
         [0117]    On the peripheral bottom surface  120   b  of the showerhead, holes  90 X for injecting the purge gas can be disposed such that they surround the injection surface  120   a . On the injection surface  120   a  adjacent to the first, second, third and fourth inner surfaces  122   a ˜ 122   d  holes  90   y  for injecting the purge gas can be disposed such that the holes  90   y  surround the injection surface  120   a.    
         [0118]    Referring to  FIG. 11 , the injection surface  120   a  of the showerhead  120  according to an embodiment of the invention is described.  FIG. 11  is a bottom view of the showerhead  120 . The showerhead  120  comprises n injection units on the injection surface  120   a , which are SU( 1 ), SU( 2 ), . . . SU(n). The injection units extend along a direction perpendicular to the first direction. SU( 1 ) and SU(n) are disposed at the both ends of the injection surface  120   a  respectively and the other injection units are disposed serially along the first direction between SU( 1 ) and SU(n). 
         [0119]    The injection units may be disposed at a constant interval X along the first direction. A width along the first direction of the injection unit may be, for example, between 30 mm and 200 mm. A hole array  90   c  for injecting the purge gas, which extends along the direction perpendicular to the first direction, may be disposed between the injection units. 
         [0120]    Each of the injection units (SU) comprises first and second hole arrays  92   a  and  92   b  for exhaust, which extend along the perpendicular direction and are disposed before and after the respective injection unit. Between the hole arrays  92   a  and  92   b  for exhaust, hole arrays  80   a  and  80   b  for injecting the source and reactant precursors respectively are disposed such that they extend parallel to the hole arrays  92   a  and  92   b.    
         [0121]    The first and second hole arrays  92   a  and  92   b  for exhaust are connected to the source of exhaust pump. The respective exhaust may be controlled individually by the gas supply control system  170 . 
         [0122]    While the source precursor is injected through the hole array  80   a  but injection of the reactant precursor through the hole array  80   b  is stopped, for example, the first hole array  92   a  for exhaust, which is adjacent to the hole array  80   a  for injecting the source precursor, is open to the source of exhaust to exhaust the source precursor through the hole array  92   a  but the connection of the second hole array  92   b , which is adjacent to the hole array  80   b  for injecting the reactant precursor, with the source of exhaust is cut off to stop exhaust through the hole array  92   b . In a similar manner, while the reactant precursor is injected through the hole array  80   b  but injection of the source precursor through the hole array  80   a  is stopped, the second hole array  92   b  for exhaust, which is adjacent to the hole array  80   b  for injecting the reactant precursor, is open to the source of exhaust to exhaust the reactant precursor through the hole array  92   b  but the connection of the first hole array  92   a , which is adjacent to the hole array  80   a  for injecting the source precursor, with the source of exhaust is cut off to stop exhaust through the hole array  92   a . Therefore the first and second hole arrays  92   a  and  92   b  can be used to exhaust the source and reactant precursors, respectively. 
         [0123]    Referring to  FIG. 11 , between the hole array  80   a  for injecting the source precursor and the hole array  80   b  for injecting the reactant precursor, a hole array  90   t  for injecting the purge gas may be disposed such that it extends parallel to the hole arrays  80   a  and  80   b.    
         [0124]    Between the hole array  80   a  for injecting the source precursor and the hole array  90   t  for injecting the purge gas, a third hole array  92   c  for exhaust may be disposed such that it extends parallel to the hole arrays  80   a  and  90   t . Between the hole array  80   b  for injecting the reactant precursor and the hole array  90   t  for injecting the purge gas, a fourth hole array  92   d  for exhaust may be disposed such that it extends parallel to the hole arrays  80   b  and  90   t.    
         [0125]    The third and fourth hole arrays  90   c  and  90   d  for exhaust are connected to source of exhaust pump. The respective exhaust may be controlled individually by the gas supply control system  170 . 
         [0126]    While the source precursor is injected through the hole array  80   a  but injection of the reactant precursor through the hole array  80   b  is stopped, for example, the first and third hole arrays  92   a  and  92   c  for exhaust, which are adjacent to the hole array  80   a  for injecting the source precursor, are open to the source of exhaust to exhaust the source precursor through the hole arrays  92   a  and  92   c  but the connection of the second and fourth hole arrays  92   b  and  92   d , which are adjacent to the hole array  80   b  for injecting the reactant precursor, with the source of exhaust is cut off to stop exhaust through the hole arrays  92   b  and  92   d . In a similar manner, while the reactant precursor is injected through the hole array  80   b  but injection of the source precursor through the hole array  80   a  is stopped, the second and fourth hole arrays  92   b  and  92   d  for exhaust, which are adjacent to the hole array  80   b  for injecting the reactant precursor, are open to the source of exhaust to exhaust the reactant precursor through the hole arrays  92   b  and  92   d  but the connection of the first and third hole arrays  92   a  and  92   c , which are adjacent to the hole array  80   a  for injecting the source precursor, with the source of exhaust is cut off to stop exhaust through the hole arrays  92   a  and  92   c . Therefore the first and third hole arrays  92   a  and  92   c  and the second and fourth hole arrays  92   b  and  92   d  can be used to exhaust the source and reactant precursors, respectively. 
         [0127]    Even though each of the hole arrays  80   a ,  80   b ,  90   s ,  90   t ,  92  illustrated in  FIG. 11  consists of the discrete holes, the holes may be connected to have a slit structure as illustrated in  FIG. 12 .  FIG. 12  is a bottom view of the injection unit comprising the slit structure which can be used in the showerhead illustrated in  FIG. 11 . 
         [0128]    Turning back to  FIG. 11 , the showerhead  120  is further described. When the showerhead  120  is located at the first location  70 , a first end of the substrate  50 , not illustrated in  FIG. 11  is located at a location  21   a , which is between a hole array  80   b  of the first injection unit SU( 1 ) for injecting the reactant precursor and a hole array  80   a  of a second injection unit SU( 2 ) for injecting the source precursor. A second end of the substrate is located at a location  21   b , which is between a hole array  80   b  of the n&#39;th injection unit SU(n) for injecting the reactant precursor and a location which is X-X1 distance away along the first direction from the hole array  80   b  of the n&#39;th injection unit SU(n) for injecting the reactant precursor. The first end of the substrate may be aligned to the hole array  80   b  of the first injection unit SU( 1 ) for injecting the reactant precursor, and the second end of the substrate may be aligned to the location which is X-X1 distance away along the first direction from the hole array  80   b  of the n&#39;th injection unit SU(n) for injecting the reactant precursor. 
         [0129]    When the showerhead  120  is located at the second location, the first end of the substrate is located at a location  22   a , which is between the hole array  80   a  of the first injection unit SU( 1 ) for injecting the source precursor and a location which is X-X1 distance away along the reverse direction of the first direction from the hole array  80   a  for injecting the source precursor. The second end of the substrate is located at a location  22   b , which is between a hole array  80   b  of the (n−1)&#39;th injection unit SU(n−1) for injecting the reactant precursor and the hole array  80   a  of the n&#39;th injection unit SU(n) for injecting the source precursor. 
         [0130]    The first end of the substrate may be aligned to the location which is X-X1 distance away along the reverse direction of the first direction from the hole array  80   a  of the first injection unit SU( 1 ) for injecting the source precursor, and the second end of the substrate may be aligned to the hole array  80   a  of the n&#39;th injection unit SU(n) for injecting the source precursor and the second end of the substrate. 
         [0131]    Referring to  FIG. 13 , a showerhead  420  according to an embodiment according of the invention is described,  FIG. 13  is a bottom view of the showerhead  420 . The showerhead  420  further comprises an injection unit SU(n+1) for injecting the source precursor. The added injection unit SU(n+1) is disposed on an end of the showerhead  420  such that it is adjacent to the n&#39;th injection unit SU(n). The injection unit SU(n+1) comprises a hole array  80   a  for injecting the source precursor, which extends to the direction perpendicular to the first direction. The injection unit SU(n+1) may further comprise hole arrays  92   a  and  92   b  for exhaust, which are disposed before and after the hole array  80   a , respectively. The hole array  80   a  for injecting the source precursor of the injection unit SU(n+1) may be disposed at a location which is a certain distance X away from the hole array  80   a  of the n&#39;th injection unit SU(n). 
         [0132]    When the showerhead  420  is located at the first location, the first end of the substrate  50  not illustrated in  FIG. 13  is located at a location  21   a , which is between the hole array  80   b  of the first injection unit SU( 1 ) and the hole array  80   a  of the second injection unit SU( 2 ). The second end of the substrate is located at a location  23   b , which is between the hole array  80   a  of the n+1&#39;th injection unit SU(n+1) and a location which is X1 distance away along the first direction from the hole array  80   a  of the n+1&#39;th injection unit SU(n+1). The first end of the substrate may be aligned to the hole array  80   b  of the first injection unit SU( 1 ), and the second end may be aligned to the location which is X1 distance away along the first direction from the hole array  80   a  of the n+1&#39;th injection unit SU(n+1). 
         [0133]    When the showerhead  420  is located at the second location, the first end of the substrate is located at a location  22   a , which is between the hole array  80   a  of the first injection unit SU( 1 ) and a location which is X-X1 distance away along the reverse direction of the first direction from the hole array  80   a  of the first injection unit SU( 1 ). The second end of the substrate is located at a location  24   b , which is between the hole array  80   a  of the n&#39;th injection unit SU(n) and the hole array  80   b  of the n&#39;th injection unit SU(n). The first end of the substrate may be aligned to a location which is X-X1 distance away along the reverse direction of the first direction from the hole array  80   a  of the first injection unit SU( 1 ), and the second end of the substrate may be aligned to the hole array  80   b  of the n&#39;th injection unit SU(n). 
         [0134]    Turning back to  FIG. 11 , a method for depositing atomic layers with the showerhead  120  according to an embodiment of the invention comprises the following steps. A method for depositing atomic layers with the showerhead  420  comprises the same steps. 
         [0135]    (1) a first moving step wherein the showerhead  120  is moved from the first location  70  to the second location  72 , 
         [0136]    (2) a source precursor injection step during the first moving step wherein the source precursor is injected to the substrate  50  through the hole array  80   a  of the injection units (SU) but supply of the reactant precursor through the hole array  80   b  is cut off, 
         [0137]    (3) a purge step during the first moving step wherein the purge gas is injected to the substrate  50  through the at least one hole arrays  90   s  and  90   t,    
         [0138]    (4) an exhaust step during the first moving step wherein the source precursor and the purge gas are exhausted through one of the at least one hole arrays  92   a - 92   d  for exhaust of the injection unit SU, 
         [0139]    (5) a second moving step wherein the showerhead  120  is moved back from the second location  72  to the first location  70  along the reverse direction of the first direction, 
         [0140]    (6) a reactant precursor injection step during the second moving step wherein the reactant precursor is injected to the substrate  50  through the hole arrays  80   b  of the injection units (SU) but supply of the source precursor through the hole array  80   a  is cut off, 
         [0141]    (7) a purge step during the second moving step wherein the purge gas is injected to the substrate  50  through the at least one hole arrays  90   s  and  90   t , and 
         [0142]    (8) an exhaust step during the second moving step wherein the reactant precursor and the purge gas are exhausted through one of the at least one hole arrays  92   a - 92   d  for exhaust of the injection unit SU, 
         [0143]    According to an embodiment of the invention, moving speeds of the showerhead  120  at the first and second moving steps may be different. For example, the speed at the first moving step is greater than the speed at the second moving step. Injection times of the source and reactant precursors can be controlled individually by using the different moving speeds. 
         [0144]    According to an embodiment of the invention, a first purge step can be added after the first moving step is completed and before the second moving step begins. During the first purge step, the source and reactant precursors are not injected and only the purge gas is injected and exhausted. 
         [0145]    According to an embodiment of the invention, a second purge step can be added after the second moving step is completed and before the first moving step begins. During the second purge step, the source and reactant precursors are not injected and only the purge gas is injected and exhausted. 
         [0146]    Purge times at the first and second purge steps can be controlled individually. It is possible to purge longer time for the precursor which is not purged well out of the source and reactant precursors. 
         [0147]    According to an embodiment of the invention, the purge gas can be injected during the first moving step through the hole array  80   b  for injecting the reactant precursor. 
         [0148]    According to an embodiment of the invention, during the first moving step, the source precursor and the purge gas are exhausted by connecting at least one of the first and third hole arrays  92   a  and  92   c  for exhaust to the source of exhaust. The second and fourth hole arrays  92   b  and  92   d  are, however, cut off from the source of exhaust. According to the embodiment, the first and third arrays  92   a  and  92   c  are used to exhaust the source precursor and the second and fourth exhausts  92   b  and  92   d  are not used to exhaust the source precursor. 
         [0149]    According to an embodiment of the invention, the purge gas can be injected during the second moving step through the hole array  80   b  for injecting the reactant precursor. 
         [0150]    According to an embodiment of the invention, during the second moving step, the reactant precursor and the purge gas are exhausted by connecting at least one of the second and fourth hole arrays  92   b  and  92   d  to the source of exhaust. The first and third hole arrays  92   a  and  92   c  are, however, cut off from the source of exhaust. According to the embodiment, the second and fourth hole arrays  92   b  and  92   d  are used to exhaust the reactant precursor and the first and third exhausts  92   a  and  92   c  are not used to exhaust the reactant precursor. 
         [0151]    According to an embodiment of the invention, a moving distance of the showerhead between the first and second locations  70  and  72  at the first and second moving steps is similar to the distance X between neighboring hole arrays  80   a  for injecting the source precursor or the pitch X of the injection units SU. It is possible to inject the source and reactant precursors and the purge gas by moving the showerhead at the distance of the distance X or the pitch X. According to the embodiment, atomic layers are deposited on the whole surface of the substrate. 
         [0152]    According to an embodiment of the invention, atomic layers can be deposited on a specific region of the substrate instead of the whole surface of the substrate by injecting the source and reactant precursors selectively on the specific region of the substrate. In case of depositing atomic layers on the specific region, the source precursor injection step (2) which is the second step of the embodiment described above is replaced with the following step (2-1). 
         [0153]    Referring to  FIG. 11 , the step (2-1) is described as below. 
         [0154]    (2-1) a source precursor injection step wherein supplies of the source and reactant precursors through the respective hole arrays  80   a  and  80   b  of the injection units (SU) are cut off while the showerhead  120  is moved from the first location  70  to the third location  74 , and the source precursor is injected through the hole array  80   a  but the supply of the reactant precursor through the hole array  80   b  is still cut off while the showerhead  120  is moved from the third location  74  to the second location  72 . 
         [0155]    The third location  74  is disposed between the first and second locations  70  and  72  such that it is closer to the first location  70 . The third location  74  may coincide with the first location  70 . 
         [0156]    In case of depositing atomic layers on the specific region, the reactant precursor injection step (6) which is the sixth step of the embodiment described above is replaced with the following step (6-1). 
         [0157]    (6-1) a reactant precursor injection step wherein supplies of the source and reactant precursors through the respective hole arrays  80   a  and  80   b  of the injection units (SU) are cut off while the showerhead  120  is moved from the second location  72  to the fourth location  74 , and the reactant precursor is injected through the hole array  80   b  but the supply of the source precursor through the hole array  80   a  is still cut off while the showerhead  120  is moved from the fourth location  76  to the first location  70 . 
         [0158]    The fourth location  76  is disposed between the first and second locations  70  and  72  such that it is closer to the second location  72 . The fourth location may coincide with the second location  72 . 
         [0159]    In the embodiment of the invention, it is possible to inject the source and reactant precursors on a part of the substrate instead of the whole surface of the substrate by making the moving distance of the showerhead  120 , that is the distance between the first and second locations  70  and  72 , smaller than the distance X between the neighboring hole arrays  80   a  or the pitch X of the injection units SU. Atomic layers are deposited only on the part of the substrate which is exposed to both of the source and reactant precursors. 
         [0160]    In the embodiment of the invention, it is possible to inject the source and reactant precursors on the part of the substrate instead of the whole surface of the substrate by making the distance between the third and fourth locations  74  and  76  smaller than the distance X between the neighboring hole arrays  80   a  or the pitch X of the injection units SU. 
         [0161]    A method of depositing the atomic layers by using the showerhead  120  according to an embodiment of the invention comprises the following steps. 
         [0162]    (1) the first moving step wherein the showerhead  120  is moved from the first location  70  to the second location  72 , 
         [0163]    (2) the source precursor injection step during the first moving step wherein the source precursor is injected to the substrate  50  through the hole array  80   a  of the injection units (SU) but the supply of the reactant precursor through the hole array  80   b  is cut off, 
         [0164]    (3) the purge step during the first moving step wherein the purge gas is injected to the substrate  50  through the at least one hole arrays  90   s  and  90   t,    
         [0165]    (4) the exhaust step during the first moving step wherein the source precursor and the purge gas are exhausted through at least one of the hole arrays  92   a - 92   d  for exhaust of the injection unit SU, 
         [0166]    (5) the second moving step wherein the showerhead  120  is moved back from the second location  72  to the first location  70  along the reverse direction of the first direction, 
         [0167]    (6) a purge step during the second moving step wherein the supplies of the source and reactant precursors through the respective hole arrays  80   a  and  80   b  of the injection units (SU) are cut off but the purge gas is injected through the at least of the hole arrays  90   s  and  90   t  for injecting the purge gas, 
         [0168]    (7) an exhaust step during the second moving step wherein the purge gas is exhausted through the at least one hole arrays  92   a - 92   d  of the injection unit SU, 
         [0169]    (8) a third moving step wherein the showerhead  120  is moved from the first location  70  to the second location  72 , 
         [0170]    (9) a reactant precursor injection step during the third moving step wherein the reactant precursor is injected to the substrate  50  through the hole array  80   b  of the injection units (SU) but the supply of the source precursor through the hole arrays  80   a  is cut off, 
         [0171]    (10) a purge step during the third moving step wherein the purge gas is injected to the substrate  50  through the at least one hole arrays  90   s  and  90   t , and 
         [0172]    (11) an exhaust step during the third moving step wherein the reactant precursor and the purge gas are exhausted through the at least one hole arrays  92   a - 92   d  for exhaust of the injection unit SU. 
         [0173]    According to an embodiment of the invention, the purge gas can be injected during the first moving step through the hole array  80   b  for injecting the reactant materials. 
         [0174]    According to an embodiment of the invention, during the first moving step, the source precursor and the purge gas are exhausted by connecting at least one of the first and third hole arrays  92   a  and  92   c  for exhaust to the source of exhaust. The second and fourth hole arrays  92   b  and  92   d  are, however, cut off from the source of exhaust. According to the embodiment, the first and third arrays  92   a  and  92   c  are used to exhaust the source precursor and the second and fourth exhausts  92   b  and  92   d  are not used to exhaust the source precursor. 
         [0175]    According to an embodiment of the invention, the purge gas can be injected during the third moving step through the hole array  80   b  for injecting the reactant materials. 
         [0176]    According to an embodiment of the invention, during the third moving step, the reactant precursor and the purge gas are exhausted by connecting at least one of the second and fourth hole arrays  92   b  and  92   d  to the source of exhaust. The first and third hole arrays  92   a  and  92   c  are, however, cut off from the source of exhaust. According to the embodiment, the second and fourth hole arrays  92   b  and  92   d  are used to exhaust the reactant precursor and the first and third exhausts  92   a  and  92   c  are not used to exhaust the reactant precursor. 
         [0177]    According to an embodiment of the invention, during the second moving step, the hole arrays  92   a - 92   d  for exhaust are cut off from the source of exhaust. In the embodiment, the purge gas injected from the hole arrays  90   s  and  90   t  may be exhausted through the hole for exhaust  112   a  of  FIG. 15  disposed on the substrate support  110  or through the hole for exhaust  109  of  FIG. 18  disposed about the substrate support. 
         [0178]    According to an embodiment of the invention, the purge gas can be injected during the second moving step through the hole arrays  80   a  and  80   b.    
         [0179]    According to an embodiment of the invention, moving speeds of the showerhead  120  at the first, second and third moving steps may be different. 
         [0180]    According to an embodiment of the invention, the moving distance of the showerhead between the first and second locations  70  and  72  at the first, second and third moving steps is similar to the distance X between neighboring hole arrays  80   a  for injecting the source precursor or the pitch X of the injection units SU. It is possible to inject the source and reactant precursors and the purge gas to the whole surface of the substrate by moving the showerhead at the distance of the distance X or the pitch X. According to the embodiment, atomic layers are deposited on the whole surface of the substrate. 
         [0181]    In the embodiment of the invention, it is possible to inject the source and reactant precursors on the part of the substrate instead of the whole surface of the substrate by making the moving distance of the showerhead  120 , that is the distance between the first and second locations  70  and  72 , smaller than the distance X between the neighboring hole arrays  80   a  or the pitch X of the injection units SU. 
         [0182]    According to an embodiment of the invention, at least one of first, second, third and fourth hole arrays  90   a - 90   d  for injecting the purge gas may be added to the injection unit (SU) described with reference to  FIG. 11 .  FIG. 14  is a bottom view of the injection unit (SU) with the additional hole arrays  90   a - 90   d  for injecting the purge gas. The first hole array  90   a  is disposed between the first hole array  92   a  for exhaust and the hole array  80   a  for injecting the first materials, the second hole array  90   b  is disposed between the third hole array  92   c  for exhaust and the hole array  80   a  for injecting the first materials, the third hole array  90   c  is disposed between the fourth hole array  92   d  for exhaust and the hole array  80   b  for injecting the second materials, and the fourth hole array  90   d  is disposed between the second hole array  92   b  for exhaust and the hole array  80   b  for injecting the second materials. 
         [0183]    The first materials injected from the hole array  80   a  is exhausted through at least one of the first and third hole arrays  92   a  and  92   c  together with the purge gas injected from the hole arrays  90   a  and  90   b  which are adjacent to the hole array  80   a . The second materials injected from the hole array  80   b  is exhausted through at least one of the second and fourth hole arrays  92   b  and  92   d  together with the purge gas injected from the hole arrays  90   c  and  90   d  which are adjacent to the hole array  80   b . The purge gas injected from the hole array  90   t  is exhausted through at least one of the third and fourth hole arrays  92   c  and  92   d.    
         [0184]    The injection unit (SU) described with reference to  FIG. 14  can be used at the showerhead  120  and  420  described with reference to  FIGS. 11 and 13 . 
         [0185]    Referring to  FIGS. 15 and 16 , the substrate support  110  according to an embodiment of the invention is described.  FIG. 15  is a top view of the substrate support  110  without the showerhead  120 .  FIG. 16  is a top view of the substrate support  110  with the showerhead  120  located at the first location  70 . 
         [0186]    The substrate support  110  comprise a first region inside of  110   a  which the substrate  50  is placed on and is in contact with the substrate, a second region outside of  110   a  and inside of  110   b  which is covered by the showerhead  120  while the showerhead  120  is moved between the first and second locations  70  and  72 , and a third region outside of  110   b  and inside of  110   c  which is not covered by the showerhead  120 . The heating element to heat the substrate may be embedded in the first region of the substrate support  110  and the cooling line may be embedded in the second and third regions to cool down the second and third regions. 
         [0187]    A hole array  112   a  for exhaust may be disposed on the third region along the boundary with the second region such that the hole array  112   a  surrounds the second region. The hole array  112   a  is configured to exhaust foreign materials which can come into inside of the showerhead  120  from outside of the showerhead  120  or the source and reactant precursors which can leak from the showerhead  120  to outside of the showerhead  120 . 
         [0188]    A hole array  112   b  for exhaust may be disposed adjacent to the third boundary on the second region along the boundary with the third region. A hole array  112   c  for exhaust can be disposed on the other region of the second region. The hole arrays  112   b  and  112   c  are configured to exhaust the source and reactant precursors which can leak from the showerhead  120  to outside of the showerhead  120 . 
         [0189]    According to an embodiment of the invention, the hole array  112   b  for exhaust disposed on the second region may be replaced with a hole array for injecting the purge gas. The purge gas injected from the hole array  112   b  may supply the purge gas required by the showerhead  120  or can be used to prevent the second region of the substrate support  110  from being contaminated with the source and reactant precursors. 
         [0190]    According to an embodiment of the invention, the hole array  112   c  for exhaust disposed on the second region may be replaced with a hole array for injecting the purge gas. The purge gas injected from the hole array  112   c  may supply the purge gas required by the showerhead  120  or can be used to prevent the second region of the substrate support  110  from being contaminated with the source and reactant precursors. 
         [0191]    Referring to  FIGS. 17 and 18 , a protecting chamber  190  to protect the showerhead  120  and the substrate support  110  is described.  FIG. 17  is a perspective three dimensional view of the protecting chamber  190 .  FIG. 18  is a cross sectional view of the ALD apparatus  100  with the protecting chamber  190 . 
         [0192]    The protecting chamber  190  is coupled to the showerhead support  106 . The protecting chamber  190  comprises a side wall, which extends from the showerhead support  106  towards the substrate support  110 . A bottom face of the protecting chamber  190  is open to the substrate support  110 . The protecting chamber  190  coupled to the showerhead support  106  can move vertically as the showerhead support  106  moves vertically. The protecting chamber  190  can approach to the showerhead  120  and the substrate support  110  through the opened bottom face. 
         [0193]    As illustrated in  FIG. 18 , the protecting chamber  190  may be configured to move down such that the lower end of the protecting chamber  190  is located about or inside the hole array  109  for exhaust which is disposed between the lower frame  102  of the ALD apparatus  100  and the substrate support  110 . The hole for exhaust  109  is disposed along the surroundings of the substrate support  110  and connected to a vacuum pump. The purge gas injected from the hole  150  for injecting the gas is isolated from the outside by the protecting chamber  190  and the purge gas is exhausted through the hole  109  for exhaust. 
         [0194]    The ALD apparatus  100  may further comprise an outer chamber  105  as illustrated in  FIG. 18 . The outer chamber provides a closed space between the upper frame  104  and the lower frame  102 . The substrate support  110 , the shafts  103 , the showerhead support  106  and the showerhead  120  are disposed inside the outer chamber  105 . A door not illustrated may be disposed at the outer chamber  105  for transferring the substrate. 
         [0195]    Although specific embodiments of the invention have been described and illustrated, the invention is not to be limited to the specific forms or arrangements of parts so described and illustrated. The scope of the invention is to be defined by the claims appended hereto and their equivalents. For example, the invention can be used to deposit the atomic layers on other objects as well as the semiconductor substrate. Although the invention has been described to deposit the atomic layers on a rectangular substrate, the invention can be used for substrate having other shapes. In case that the substrate is circular, for example, both ends  120   r  of the showerhead  120  or the injection surface  120   a  may be configured to have arc shape as illustrated in  FIG. 19 , which is a bottom view of the showerhead  120  configured to deposit the atomic layers on the circular substrate  50 . Even though the hole array  92  for exhaust and the hole array  90  for injecting the purge gas have not been illustrated in the injection unit (SU) used in the showerhead  120  of  FIG. 19 , the injection unit (SU) described with reference to  FIGS. 11 and 14  may be used as the injection unit (SU) in the showerhead  120  of  FIG. 19 . 
         [0196]    The invention has been described to deposit the atomic layers with the showerhead  120  moving back and forth linearly. However, the atomic layers can be also deposited by pivoting the showerhead  120  back and forth instead of the linear moving. 
         [0197]    Referring to  FIGS. 20 and 21 , an apparatus and a method to deposit the atomic layers by the pivoting back and forth motions are described.  FIG. 20  is a top view of the ALD apparatus  500  comprising a pivoting back and forth mechanism.  FIG. 21  is a cross sectional view of the cross section  510  of the ALD apparatus illustrated in  FIG. 20 . The ALD apparatus  500  comprises a pivoting showerhead  520 , which is disposed over the substrate support  110 . One end  520   a  of the pivoting showerhead  520  is coupled to a shaft  524  and the shaft  524  is pivotably coupled to a frame of the ALD apparatus  500  such as the lower frame  102 . The shaft  524  is coupled to a pivoting device not illustrated in  FIGS. 20 and 21  such that the shaft  524  can pivot about a vertical axis  530 . 
         [0198]    The opposite end  520   b  of the showerhead  520  extends from the shaft  524  through an edge of the substrate close to the shaft  524  to about an opposite edge of the substrate. Therefore a length between the both ends of the showerhead  520  is configured to be greater than a diameter or a width of the substrate  50 . 
         [0199]    An injection surface  120   a  is disposed on a bottom surface of the showerhead  520 . On the injection surface  120   a , at least one injection unit (SU) described with reference to  FIG. 14  is disposed. A bottom view of the showerhead  520  having the injection unit described with reference to  FIG. 14  is illustrated in  FIG. 22 . The injection unit (SU) is disposed on the injection surface  120   a  such that hole arrays of the injection unit (SU) are disposed along the length direction of the showerhead  520 . The injection unit (SU) is connected to the gas injection control system  170 , the source and reactant precursors  172 , the purge gas  172  and the exhaust pump  172 , which were described with reference to  FIGS. 3 and 4 . 
         [0200]    The showerhead  520  can be reciprocated between first and second angular locations  530   a  and  530   b  by pivoting the shaft  524  about the vertical axis  530 . An angle between the first and second angular locations may be smaller than 90 degrees. The first angular location  530   a  is the location where the source precursor injected from the hole array  80   a  of the showerhead  520  and the reactant precursor injected from the hole array  80   b  of the showerhead  520  can coat an edge  50   a  of the substrate  90 . The second angular location  530   b  is the location where the source precursor injected from the hole array  80   a  of the showerhead  520  and the reactant precursor injected from the hole array  80   b  of the showerhead  520  can coat an opposite edge  50   b  of the substrate  90 . At the first angular location  520   a , the hole array  80   a  or the hole array  80   b  may be aligned to the edge  50   a . At the second angular location  520   b , the hole array  80   a  or the hole array  80   b  may be aligned to the edge  50   b.    
         [0201]    Around the substrate support  110  of the ALD apparatus  500 , multiple holes  112   a  for exhaust are disposed. The holes  112   a  for exhaust are configured to exhaust the source and reactant precursors and the purge gas injected from the injection surface  120   a  of the showerhead  520 . The pivoting showerhead  520  may be disposed such that a gap between the surface of the substrate  50  and the injection surface  120   a  of the showerhead  520  is between 0.1 mm and 30 mm. The substrate support  110  and the pivoting showerhead  520  may be disposed in the chamber  105  as illustrated in  FIG. 21 . 
         [0202]    Referring to  FIGS. 20 and 22 , a method of depositing the atomic layers by using the showerhead  520  comprises the following steps. 
         [0203]    (1) a first pivoting step wherein the showerhead  520  is pivoted from the first angular location  520   a  to the second angular location  520   b,    
         [0204]    (2) a source precursor injection step during the first pivoting step wherein the source precursor is injected to the substrate  50  through the hole array  80   a  of the showerhead  520  but supply of the reactant precursor through the hole array  80   b  of the showerhead  520  is cut off, 
         [0205]    (3) a purge step during the first pivoting step wherein the purge gas is injected to the substrate  50  through at least one hole array  90   t  of the showerhead  520 , 
         [0206]    (4) an exhaust step during the first pivoting step wherein the source precursor and the purge gas are exhausted through at least one of the hole arrays  92   a - 92   d  for exhaust of the showerhead  520 , 
         [0207]    (5) a second pivoting step wherein the showerhead  520  is pivoted back from the second angular location  520   b  to the first angular location  520   a,    
         [0208]    (6) a reactant precursor injection step during the second pivoting step wherein the reactant precursor is injected to the substrate  50  through the hole array  80   b  of the showerhead  520  but supply of the source precursor through the hole array  80   a  of the showerhead  520  is cut off, 
         [0209]    (7) a purge step during the second pivoting step wherein the purge gas is injected to the substrate  50  through the at least one hole array  90   t  of the showerhead  520 , and 
         [0210]    (8) an exhaust step during the second pivoting step wherein the reactant precursor and the purge gas are exhausted through the at least one of the hole arrays  92   a - 92   d  for exhaust of the showerhead  520 , 
         [0211]    Another method of depositing the atomic layers by using the showerhead  520  comprises the following steps. 
         [0212]    (1) the first pivoting step wherein the showerhead  520  is pivoted from the first angular location  520   a  to the second angular location  520   b,    
         [0213]    (2) the source precursor injection step during the first pivoting step wherein the source precursor is injected to the substrate  50  through the hole array  80   a  of the showerhead  520  but the supply of the reactant precursor through the hole array  80   b  of the showerhead  520  is cut off, 
         [0214]    (3) the purge step during the first pivoting step wherein the purge gas is injected to the substrate  50  through the at least one hole array  90   t  of the showerhead  520 , 
         [0215]    (4) the exhaust step during the first pivoting step wherein the source precursor and the purge gas are exhausted through the at least one of the hole arrays  92   a - 92   d  for exhaust of the showerhead  520 , 
         [0216]    (5) the second pivoting step wherein the showerhead  520  is pivoted back from the second angular location  520   b  to the first angular location  520   a,    
         [0217]    (6) a purge step during the second pivoting step wherein the purge gas is injected to the substrate  50  through the at least one hole array  90   t  but the supplies of the source and reactant precursors through the hole array  80   a  and  80   b  of the showerhead  520  are cut off, 
         [0218]    (7) an exhaust step during the second pivoting step wherein the purge gas is exhausted through at least one of the hole arrays  92   a - 92   d  for exhaust of the showerhead  520 , 
         [0219]    (8) a third pivoting step wherein the showerhead  520  is pivoted again from the first angular location  520   a  to the second angular location  520   b,    
         [0220]    (9) a reactant precursor injection step during the third pivoting step wherein the reactant precursor is injected to the substrate  50  through the hole array  80   b  of the showerhead  520  but the supply of the source precursor through the hole array  80   a  of the showerhead  520  is cut off, 
         [0221]    (10) a purge step during the third pivoting step wherein the purge gas is injected to the substrate  50  through the at least one hole array  90   t  of the showerhead  520 , and 
         [0222]    (11) an exhaust step during the third pivoting step wherein the reactant precursor and the purge gas are exhausted through the at least one of the hole arrays  92   a - 92   d  for exhaust of the showerhead  520 . 
         [0223]    The showerhead  120  described with reference to  FIG. 11  may comprise at least one purge gas injection surface  120   n  as illustrated in  FIG. 23 .  FIG. 23  is a bottom view of the showerhead  120   x  comprising the purge gas injection surface  120   n . The purge gas injection surface  120   n  is disposed on the injection surface  120   a  such that it extends along the first direction from an edge of the injection surface  120   a  to the opposite end. The purge gas injection surface comprises a hole  90   x  for injecting the purge gas and does not comprise holes for injecting the source and reactant precursors. The purge gas injection surface may further comprise a hole  92   x  for exhaust. The hole array  92   x  for exhaust may be disposed along the periphery of the purge gas injection surface  120   n  parallel to the first direction. The hole array  90 X for injecting the purge gas may be disposed between the hole arrays  92   x  for exhaust. 
         [0224]    The atomic layers are not deposited on a surface of the substrate corresponding to the purge gas injection surface  120   n  because the source and reactant precursors are not injected to the surface. It is possible not to deposit the atomic layers on a specific region  50   a  of the substrate  50  not illustrated in  FIG. 23  by disposing the purge gas injection unit  120   n  such that it is aligned to the specific region. 
         [0225]    According to an embodiment of the invention, the purge gas injection surface  120   n  may be configured not to inject any gas by not comprising the hole  90   x  for injecting the purge gas and the hole  92   x  for exhaust. 
         [0226]    According to an embodiment of the invention, the purge gas injection surface  120   n  may be configured to comprise only the hole  92   x  for exhaust. 
         [0227]    A width, a location and a number of the purge gas injection surface  120   n  may be adjusted according to a shape and a location of the specific region  50   a.    
         [0228]    Turning back to  FIG. 23 , an embodiment of the invention to deposit the atomic layers by using the showerhead  120   x  comprises the following steps. 
         [0229]    (1) a first moving step wherein the showerhead  120   x  is moved along the first direction from the first location  70  to the second location  72 , 
         [0230]    (2) a source precursor injection step during the first moving step wherein the supplies of the source and reactant precursors through the hole arrays  80   a  and  80   b  of the injection units (SU) are cut off while the showerhead  120   x  is moved from the first location  70  to the third location  74 , and wherein the source precursor is injected through the hole array  80   a  but the supply of the reactant precursor through the hole array  80   b  is still cut off while the showerhead  120  is moved from the third location  74  to the second location  72 . 
         [0231]    (3) a purge step during the first moving step wherein the purge gas is injected to the substrate  50  through the at least one hole array  90   s  and  90   t  of the injection units SU, 
         [0232]    (4) an exhaust step during the first moving step wherein the source precursor and the purge gas are exhausted through at least one of the hole arrays  92   a - 92   d  for exhaust of injection units SU, 
         [0233]    (5) a second moving step wherein the showerhead  120   x  is moved from the second location  72  to the first location  70 , 
         [0234]    (6) a reactant precursor injection step during the second moving step wherein the supplies of the source and reactant precursors through the hole arrays  80   a  and  80   b  of the injection units (SU) are cut off while the showerhead  120   x  is moved from the second location  72  to the fourth location  76 , and wherein the reactant precursor is injected through the hole array  80   b  but the supply of the source precursor through the hole array  80   a  is still cut off while the showerhead  120  is moved from the fourth location  76  to the first location  70 . 
         [0235]    (7) a purge step during the second moving step wherein the purge gas is injected to the substrate  50  through the at least one hole array  90   s  and  90   t  of the injection units SU, 
         [0236]    (8) an exhaust step during the second moving step wherein the reactant precursor and the purge gas are exhausted through the at least one of the hole arrays  92   a - 92   d  for exhaust of injection units SU, 
         [0237]    According to the embodiment, the atomic layers are deposited only when the showerhead  120   x  is located between the third and fourth locations  74  and  76 . The atomic layers are not deposited when the showerhead  120   x  is located between the first and third locations  70  and  74  or between the second and fourth locations  72  and  76  because both of the source and reactant precursors are required to deposit the atomic layers. 
         [0238]    According to the embodiment, the third location  74  is between the first and second locations  70  and  72 . It may be closer to the first location  70  or coincides with the first location  70 . 
         [0239]    According to the embodiment, the fourth location  76  is between the first and second locations  70  and  72 . It may be closer to the second location  72  or coincides with the second location  72 . 
         [0240]    According to the embodiment, it is possible to inject the source and reactant precursors to a part of the substrate instead of the whole surface by making the moving distance of the showerhead  120   x , which is the distance between the first and second locations  70  and  72 , smaller than the distance X between the neighboring hole arrays  80   a  for injecting the source precursor of the injection units SU. 
         [0241]    According to the embodiment, the purge gas can be injected through the purge gas injection surface  120   n  but the source and reactant precursors are not injected. 
         [0242]    According to the embodiment, only the exhaust is carried out through the purge gas injection surface  120   n  but the source and reactant precursors are not injected. 
         [0243]    According to the embodiment, the purge gas can be injected and the exhaust can be carried out through the purge gas injection surface  120   n  but the source and reactant precursors are not injected. 
         [0244]    Referring to  FIG. 24 , a shape of the atomic layers which can be deposited on the substrate  50  by using the showerhead  120   x  illustrated in  FIG. 23  is described.  FIG. 24  is a top view of the substrate  50 . 
         [0245]    On the substrate  50 , a first region  210 ( 1 ) deposited by the first injection unit SU( 1 ) of the showerhead  120   x , a second region  210 ( 2 ) deposited by the second injection unit SU( 2 ) of the showerhead  120   x , . . . , a (n−1)&#39;th region  210 ( n −1) deposited by the (n−1)&#39;th injection unit SU(n−1) of the showerhead  120   x , and a n&#39;th region  210 ( n ) deposited by the n&#39;th injection unit SU(n) of the showerhead  120   x  are formed. For example, only the first region  210 ( 1 ) is formed in case that the showerhead  120   x  comprises only the first injection unit SU( 1 ). 
         [0246]    A width  240  of the atomic layers  210  along the first direction is determined by the distance between the third and fourth locations  74  and  76  which were described with reference to  FIG. 23 . The regions  210  are separated each other. The separation  220  along the first direction is the separation made by the embodiment described with reference to  FIG. 23  and the separation  230  along the direction perpendicular to the first direction is the separation made by the purge gas injection surface  120   n  of the showerhead  120   x . The separation  220  along the first direction can be controlled by adjusting the distance between the third and fourth locations  74  and  76 . The separation  230  along the perpendicular direction can be controlled by adjusting the width, configuration and shape of the purge gas injection surface  120   n  of the showerhead  120   x . According to the embodiment, it is possible to deposit the atomic layers selectively on the specific regions of the substrate  50  without using the shadow mask. 
         [0247]    Although specific embodiments of the invention have been described and illustrated, the invention is not to be limited to the specific forms or arrangements of parts so described and illustrated. The scope of the invention is to be defined by the claims appended hereto and their equivalents.