Abstract:
Provided is a thin-film thickness measurement apparatus including a light output unit including a light emitter configured to emit light onto a target. A light receiving unit is configured to receive light reflected from the target. A blowing unit is configured to eject a gas around the light emitter.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2015-0139105, filed on Oct. 2, 2015, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
         [0002]    1. Technical Field 
         [0003]    One or more exemplary embodiments of the present invention relate to a thin-film thickness measurement apparatus, and more particularly to a thin-film deposition apparatus including the same. 
         [0004]    2. Discussion of Related Art 
         [0005]    During a thin-film manufacturing process for forming a thin-film of an organic light-emitting display apparatus, a deposition process may be used to attach the thin-film on a substrate surface by supplying a deposition source. 
         [0006]    Uniformity of a light-emitting characteristic of the organic light-emitting display apparatus may be obtained by maintaining an accurate thickness. Thus, it may be desirable to have a thin-film thickness measurement apparatus for measuring the thickness of the thin-film that is maintained in a relatively uncontaminated state even after being used for a relatively long period of time. 
       SUMMARY 
       [0007]    One or more exemplary embodiments of the present invention may include a thin-film thickness measurement apparatus, which may reduce or eliminate a deterioration of measurement accuracy of the thin-film thickness measurement apparatus and a thin-film deposition apparatus including the thin-film thickness measurement apparatus. The deterioration of the measurement accuracy of the thin-film thickness measurement apparatus may result from contamination of the thin-film thickness measurement apparatus. 
         [0008]    According to one or more exemplary embodiments of the present invention, a thin-film thickness measurement apparatus includes a light output unit including a light emitter configured to emit light onto a target. A light receiving unit is configured to receive light reflected from the target. A blowing unit is configured to eject a gas around the light emitter. 
         [0009]    The light output unit may include a housing including a light source. An optical fiber may project from the housing to radiate light from the light source towards the target. 
         [0010]    The blowing unit may include an ejecting block ejecting a gas towards a front end of the optical fiber facing the target. A sucking block may collect the gas ejected from the ejecting block. 
         [0011]    The blowing unit may be configured to create air circulation including the gas from the ejecting block to the sucking block around the front end of the optical fiber. 
         [0012]    The ejecting block and the sucking block may be coupled to the housing. An inflow line connected to the ejecting block and a discharge line connected to the sucking block may be disposed in the housing. 
         [0013]    The ejecting block and the sucking block may include an acetal material. 
         [0014]    The gas may include nitrogen. 
         [0015]    According to one or more exemplary embodiments of the present invention, a thin-film deposition apparatus includes a deposition chamber configured to house a target. A deposition source supplier is configured to supply a source of a thin-film to be deposited on the target. A thin-film thickness measurement apparatus is configured to measure a thickness of the thin-film deposited on the target. The thin-film thickness measurement apparatus includes a light output unit including a light emitter configured to emit light onto the target. A light receiving unit is configured to receive light reflected from the target. A blowing unit is configured to eject a gas around the light emitter. 
         [0016]    The light output unit may include a housing including a light source. An optical fiber may project from the housing to radiate light from the light source towards the target. 
         [0017]    The blowing unit may include an ejecting block ejecting a gas towards a front end of the optical fiber facing the target. A sucking block may collect the gas ejected from the ejecting block. 
         [0018]    The blowing unit may be configured to create air circulation including the gas from the ejecting block to the sucking block around the front end of the optical fiber. 
         [0019]    The ejecting block and the sucking block may be coupled to the housing. An inflow line connected to the ejecting block and a discharge line connected to the sucking block may be disposed in the housing. 
         [0020]    The ejecting block and the sucking block may include an acetal material. 
         [0021]    The gas may include nitrogen. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The above and other features of the present invention will become more apparent by describing in detail exemplary embodiments thereof, with reference to the accompanying drawings, in which: 
           [0023]      FIG. 1  is a diagram schematically illustrating a structure of a thin-film deposition apparatus including a thin-film thickness measurement apparatus, according to an exemplary embodiment of the present invention; 
           [0024]      FIG. 2  is a front view of the thin-film thickness measurement apparatus of  FIG. 1 ; 
           [0025]      FIG. 3  is a diagram depicting an air circulation formed by a blowing unit of the thin-film thickness measurement apparatus of  FIG. 2 ; 
           [0026]      FIG. 4  is a graph showing a light quantity decreasing state of the thin-film thickness measurement apparatus of  FIG. 2  according to time, together with a comparative example; and 
           [0027]      FIG. 5  is a cross-sectional view of an organic light-emitting display apparatus as an example of a target for performing deposition by using the thin-film deposition apparatus of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. In this regard, the exemplary embodiments may have different forms and should not be construed as being limited to the exemplary embodiments of the present invention described herein. 
         [0029]    In the specification and drawings, like reference numerals may refer to like elements. 
         [0030]    Sizes of elements in the drawings may be exaggerated for clarity of description. 
         [0031]    A specific process order according to exemplary embodiments of the present invention may be performed differently from the described order. 
         [0032]      FIG. 1  is a diagram schematically illustrating a structure of a thin-film deposition apparatus including a thin-film thickness measurement apparatus, according to an exemplary embodiment of the present invention. 
         [0033]    Referring to  FIG. 1 , a thin-film deposition apparatus  100  according to an exemplary embodiment of the present invention may include a deposition source supplier  30  supplying a source of a thin-film towards a substrate  20 . The substrate  20  may be a deposition target inside a deposition chamber  40 . A thin-film thickness measurement apparatus  10  may measure a thickness of the thin-film formed on the substrate  20  in the chamber  40 . 
         [0034]    Thus, when the deposition source supplier  30  supplies the source of the thin-film inside the deposition chamber  40 , the thin-film may be deposited on the substrate  20  to form the thin-film having a certain thickness. 
         [0035]    A mask having a pattern of the thin-film may be disposed between the deposition source supplier  30  and the substrate  20 . 
         [0036]    The thin-film thickness measurement apparatus  10  may be an apparatus measuring a thickness of a thin-film deposited on the substrate  20 , and may have a structure shown in  FIG. 2 . 
         [0037]      FIG. 2  is a front view of the thin-film thickness measurement apparatus  10  of  FIG. 1 . Referring to  FIG. 2 , the thin-film thickness measurement apparatus  10  may include a light output unit  11  radiating light for measuring a thickness of a thin-film on the substrate  20 , and a light receiving unit  12  receiving light that is radiated from the light output unit  11  and reflected from the substrate  20 . The thickness of the thin-film may be calculated as the light receiving unit  12  receives the light radiated from the light output unit  11  and reflected from the substrate  20 . The light receiving unit  12  may measure a change of a polarization state of the light. For example, the thickness of the thin-film may be measured according to substantially the same principle as an ellipsometer. 
         [0038]    The thin-film thickness measurement apparatus  10  may include a blowing unit  13  that directly ejects and circulates a clean nitrogen gas to a light emitter of the light output unit  11 . The blowing unit  13  may increase measurement accuracy of the thin-film thickness measurement apparatus  10  and may increase productivity of a deposition process. 
         [0039]    The light output unit  11  may include a housing  11   c  including a light source  11   b,  and an optical fiber  11   a  projecting from the housing  11   c.  The optical fiber  11   a  may transmit light from the light source  11   b  to the substrate  20 . Thus, light radiated from the light source  11   b  may be emitted from a front end of the optical fiber  11   a  facing the substrate  20  and onto the substrate  20 . If the front end of the optical fiber  11   a  is contaminated, light output quantity may be reduced, and thus measurement accuracy of the thin-film deposited on the substrate  20  may be reduced. The light output unit  11  may be disposed in the chamber  40  in which a deposition process is performed, and thus the front end of the optical fiber  11   a  may be contaminated by the source of the thin-film. When the front end of the optical fiber  11   a  is contaminated and the light output quantity is reduced, the thickness of the thin-film might not be accurately measured. Thus, the deposition process may be stopped periodically, and a process of cleaning the front end of the optical fiber  11   a  after opening the deposition chamber  40  may be performed, which may reduce productivity. 
         [0040]    When the blowing unit  13  is used, the front end of the optical fiber  11   a  may be maintained in a relatively clean state even while the deposition process is performed. Thus, periodic stopping of the deposition process to clean the front end of the optical fiber  11   a  may be reduced or eliminated. 
         [0041]    The blowing unit  13  may include an ejecting block  13   a  ejecting a clean external nitrogen gas to the front end of the optical fiber  11   a,  a sucking block  13   b  collecting the ejected nitrogen gas, an inflow line  13   c  transferring the clean external nitrogen gas outside the deposition chamber  40  to the ejecting block  13   a,  and a discharge line  13   d  discharging the nitrogen gas collected by the sucking block  13   b.  The ejecting block  13   a  and the sucking block  13   b  may be disposed on the housing  11   c,  and the inflow line  13   c  and the discharge line  13   d  may pass through inside the housing  11   c.    
         [0042]      FIG. 3  is a diagram depicting an air circulation formed by a blowing unit of the thin-film thickness measurement apparatus of  FIG. 2 . Referring to  FIG. 3 , the air circulation of a clean nitrogen gas supplied from the blowing unit  13  may be formed around the front end of the optical fiber  11   a.  The clean nitrogen gas may be introduced from outside the deposition chamber  40  through the inflow line  13   c  and may be ejected towards the front end of the optical fiber  11   a  through the ejecting block  13   a.  The ejected nitrogen gas may be sucked through the sucking block  13   b,  and then discharged through the discharge line  13   d.  Thus, the clean nitrogen gas may circulate around the front end of the optical fiber  11   a.    
         [0043]    The inside of the deposition chamber  40  in which the deposition process is performed may have a nitrogen gas atmosphere. As the deposition process is performed, the nitrogen gas atmosphere may change to a contaminated gas state in which the source of the thin-film is mixed into the atmosphere in the deposition chamber  40 . When the clean nitrogen gas circulates around the front end of the optical fiber  11   a,  the front end coming into contact with a contaminated gas inside the deposition chamber  40  may be reduced or eliminated. Thus, the front end may continuously maintain a clean state even when a separate cleaning operation is not performed. 
         [0044]      FIG. 4  is a graph showing a light quantity decreasing state of the thin-film thickness measurement apparatus of  FIG. 2  according to time, together with a comparative example. Referring to  FIG. 4 , the graph shows a decreasing degree of a light output quantity when the blowing unit  13  is activated, together with a comparative example L2. In the comparative example L2 in which a deposition operation is performed without the blowing unit  13 , a light quantity may decrease relatively rapidly according to time. In an example L1 according to an exemplary embodiment of the present invention in which the blowing unit  13  is activated, a light quantity may decrease relatively slowly. 
         [0045]    The front end of the optical fiber  11   a  in the comparative example L2 may be cleaned once in two weeks, and the front end of the optical fiber  11   a  in the example L1 may be be cleaned once in four months to maintain measurement accuracy. 
         [0046]    The thin-film deposition apparatus  100  may include the thin-film thickness measurement apparatus  10  according to an exemplary embodiment of the present invention. A method of using the thin-film deposition apparatus will be described in more detail below. 
         [0047]    The substrate  20  may be disposed inside the deposition chamber  40  including the deposition source suppler  30  and the thin-film thickness measurement apparatus  10 . 
         [0048]    When the source of the thin-film is supplied from the deposition source supplier  30 , the thin-film may be formed on the substrate  20 , and the thin-film thickness measurement apparatus  10  may measure the thickness of the thin-film in substantially real-time. The thin-film thickness measurement apparatus  10  may provide the thickness measurement back to the thin-film deposition apparatus  100 . 
         [0049]    The blowing unit  13  may be activated in the thin-film thickness measurement apparatus  10  to circulate clean nitrogen at the front end of the optical fiber  11   a.  Thus, the thickness of the thin-film may be accurately measured even if the deposition process is performed for a relatively long period of time. 
         [0050]    The thin-film deposition apparatus  100  may be used, for example, to form a pattern of an organic film or a counter electrode of an organic light-emitting display apparatus. 
         [0051]      FIG. 5  is a cross-sectional view of an organic light-emitting display apparatus as an example of a target for performing deposition by using the thin-film deposition apparatus of  FIG. 1 . The substrate illustrated in  FIG. 5  may be substantially the same as the substrate  20  of the organic light-emitting display apparatus illustrated in  FIG. 1 . 
         [0052]    Referring to  FIG. 5 , a buffer layer  20   a  may be disposed on the substrate  20 , and a thin-film transistor TFT may be disposed on the buffer layer  20   a.    
         [0053]    The thin-film transistor TFT may include a semiconductor active layer  21 , a gate insulating film  20   b  covering the semiconductor active layer  21 , and a gate electrode  22  disposed on the gate insulating film  20   b.    
         [0054]    An interlayer insulating film  20   c  may cover the gate electrode  22 , and a source electrode  24  and a drain electrode  23  may be disposed on the interlayer insulating film  20   c.    
         [0055]    The source electrode  24  and the drain electrode  23  may respectively contact a source region and a drain region of the semiconductor active layer  21  through contact holes formed in the gate insulating film  20   b  and the interlayer insulating film  20   c.    
         [0056]    A pixel electrode  25  of an organic light-emitting device OLED may be connected to the drain electrode  23 . The pixel electrode  25  may be disposed on a planarization film  20   d,  and a pixel-defining layer  20   e  may cover the pixel electrode  25 . An opening may be formed in the pixel-defining layer  20   e.  An organic film  26  of the organic light-emitting device OLED may be disposed in the opening. A counter electrode  27  may be disposed on the organic film  26 . 
         [0057]    When the thin-film deposition apparatus  100  according to an exemplary embodiment of the present invention is used to form the organic film  26  or the counter electrode  27 , a thin film having a precise thickness may be formed as described above, and a maintenance time for cleaning may be reduced, thus increasing productivity. 
         [0058]    Thus, by using the thin-film thickness measurement apparatus  10  and the thin-film deposition apparatus  100 , the light emitter of the thin-film thickness measurement apparatus  10  including the clean nitrogen gas circulation may be maintained in a relatively clean state. Thus, measurement accuracy of a thickness of a deposited thin-film may increase, and a separate maintenance time for cleaning the light emitter of the thin-film thickness measurement apparatus  10  may be reduced or eliminated, thus increasing productivity of a deposition process. 
         [0059]    The ejecting block  13   a  and the sucking block  13   b  of the blowing unit  13  may include an acetal material. Thus, the blowing unit  13  may have a relatively strong structure and an undesired leakage of gas may be reduced or eliminated. 
         [0060]    While the present invention has been shown and described with reference to the exemplary embodiments thereof, it will be apparent to those of ordinary skill in the art that various changes in form and detail may be made thereto without departing from the spirit and scope of the present invention.