Abstract:
An electrostatic chucking apparatus and a method for manufacturing the same is disclosed, which is capable of enabling the increase of lifetime of an electrostatic chuck and realizing a uniform temperature gradient in an entire substrate by preventing an insulating material from being etched, the electrostatic chucking apparatus comprising a base member; and an electrostatic chuck, loaded onto the base member, for chucking a substrate by an electrostatic force, wherein the electrostatic chuck comprises an insulating member formed on the base member and provided with a plurality of first insulating sheets of aluminum nitride; a heater for heating the substrate, the heater positioned among the plurality of first insulating sheets; a direct current electrode formed on at least one first insulating sheet provided above the heater among the plurality of first insulating sheets, the DC electrode electrically connected with a direct current power source; and an insulator etch stopping layer, formed of aluminum oxide on an entire surface of the insulating member, for preventing the insulating member from being etched.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the Korean Patent Application No. P2008-0105949, filed on Oct. 28, 2008, which is hereby incorporated by reference as if fully set forth herein. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an electrostatic chuck and a method for manufacturing the same, and more particularly, to an electrostatic chucking apparatus which is capable of enabling the increase of lifetime of an electrostatic chuck and realizing a uniform temperature gradient in an entire substrate by preventing an insulating material from being etched, and a method for manufacturing the same. 
         [0004]    2. Discussion of the Related Art 
         [0005]    Generally, a semiconductor device, a flat display device or a solar cell can be manufactured by oxidization, deposition and etching processes. These processes are carried out under such circumstance a substrate is fixedly loaded onto a chamber. For fixedly loading the substrate onto the chamber, a mechanical method or a vacuum chucking method has been used widely. In recent, an electrostatic chucking apparatus using an electrostatic force is more preferred. 
         [0006]    The electrostatic chucking apparatus can be applied to entire steps for manufacturing the semiconductor device, for example, chemical vapor deposition, etching, sputtering, and ion implantation steps. 
         [0007]    The electrostatic chucking apparatus chucks the substrate by Coulombic Force and Johnson-Rahbeck Force generated in an insulating layer positioned between an electrode and the substrate. 
         [0008]      FIG. 1  illustrates a related art electrostatic chucking apparatus. 
         [0009]    Referring to  FIG. 1 , the related art electrostatic chucking apparatus includes a base member  10  and an electrostatic chuck  20 . The base member  10  is formed of an aluminum material, and the electrostatic chuck  20  is formed on the base member  10 . 
         [0010]    The base member  10  includes a passage  12  for heating a substrate (not shown), chucked to the electrostatic chuck  20 , to a predetermined temperature. According as an externally-provided fluid  15  with a high temperature passes through the passage  12 , the base member  10  transmits heat of the fluid  15  to the substrate, whereby the substrate electrostatic-chucked to the electrostatic chuck  20  is heated to the predetermined temperature. 
         [0011]    The electrostatic chuck  20  includes an insulating member  22 , and a direct current electrode (DC electrode)  24  formed inside the insulating member  22 . As the electrostatic chuck  20  supplies a direct current power source to the DC electrode  24 , an electrostatic force is generated in the insulating member  22 , whereby the substrate (not shown) is electrostatic-chucked to the electrostatic chuck  20 . Also, the electrostatic chuck  20  heats the substrate, which is electrostatic-chucked to the insulating member  22 , to the predetermined temperature by using the heat of the fluid  15  transmitted from the base member  10 . 
         [0012]    However, the related art electrostatic chucking apparatus has the following disadvantages. 
         [0013]    In the related art electrostatic chucking apparatus, the insulating member  22  may be etched by plasma (or etching gas) when cleaning a chamber by etching during or after the process, whereby a lifetime of the electrostatic chuck  20  may be shortened. Due to the short lifetime of the electrostatic chuck  20 , the electrostatic chuck  20  has to be frequently replaced so that a yield is lowered and a maintenance cost is increased. 
         [0014]    Since the base member  10  is different from the insulating member  22  of the electrostatic chuck  20  in thermal conductivity, and the passage  15  is distant from the substrate, it is difficult to realize a uniform temperature in the entire substrate. Furthermore, due to the imprecise temperature adjustment in the substrate, it is difficult to realize a uniform temperature gradient in the entire substrate. 
       SUMMARY OF THE INVENTION 
       [0015]    Accordingly, the present invention is directed to a an electrostatic chucking apparatus and a method for manufacturing the same that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
         [0016]    An object of the present invention is to provide an electrostatic chucking apparatus which is capable of enabling the increase of lifetime of an electrostatic chuck and realizing a uniform temperature gradient in an entire substrate by preventing an insulating material from being etched, and a method for manufacturing the same. 
         [0017]    Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
         [0018]    To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, an electrostatic chucking apparatus comprises a base member; and an electrostatic chuck, loaded onto the base member, for chucking a substrate by an electrostatic force, wherein the electrostatic chuck comprises an insulating member formed on the base member and provided with a plurality of first insulating sheets of aluminum nitride; a heater for heating the substrate, the heater positioned among the plurality of first insulating sheets; a direct current electrode formed on at least one first insulating sheet provided above the heater among the plurality of first insulating sheets, the DC electrode electrically connected with a direct current power source: and an insulator etch stopping layer, formed of aluminum oxide on an entire surface of the insulating member, for preventing the insulating member from being etched. 
         [0019]    At this time, the insulating member comprises a first insulating layer on the base member, the first insulating layer comprising at least one first insulating sheet being in contact: a second insulating layer on the first insulating layer under such circumstances that the heater is interposed therebetween, the second insulating layer comprising at least one first insulating sheet being in contact; and a third insulating layer on the second insulating layer under such circumstances that the DC electrode is interposed therebetween, the third insulating layer comprising at least one first insulating sheet being in contact. 
         [0020]    Also, the insulator etch stopping layer comprises at least one second insulating sheet of aluminum oxide being in contact with the insulating member. 
         [0021]    The heater comprises an internal heater heated by a first heater source and positioned at the central portion of the first insulating layer; and an external heater heated by a second heater source and positioned in the margin of the first insulating layer. 
         [0022]    In addition, the electrostatic chucking apparatus further comprises a focus ring covering lateral sides of the electrostatic chuck, the focus ring formed on the base member. 
         [0023]    The focus ring is formed of aluminum oxide. 
         [0024]    In another aspect of the present invention, a method for manufacturing an electrostatic chucking apparatus comprises forming a first insulating layer of a first insulating material; providing a heater on the first insulating layer; forming a second insulating layer of the first insulating material on the first insulating layer under such circumstances that the heater is interposed between the first and second insulating layers; forming a direct current electrode on the second insulating layer, the DC electrode electrically connected with a direct current power source; forming a third insulating layer of the first insulating material on the DC electrode; forming an insulator etch stopping layer on the third insulating layer, wherein the insulator etch stopping layer is formed of a second insulating material which is different from the first insulating material; manufacturing an electrostatic chuck by adhering the first to third insulating layers including the heater and the DC electrode to the insulator etch stopping layer; and loading the electrostatic chuck onto the base member. 
         [0025]    Each of the first to third insulating layers is formed of at least one first insulating sheet of the first insulating material. 
         [0026]    The first insulating material is aluminum nitride. 
         [0027]    The second insulating material is aluminum oxide. 
         [0028]    The process of providing the heater on the first insulating layer comprises providing an internal heater heated by a first heater source at the central portion of the first insulating layer; and providing an external heater heated by a second heater source in the margin of the first insulating layer. 
         [0029]    In addition, the method further comprises forming a focus ring covering lateral sides of the electrostatic chuck on the base member. 
         [0030]    The focus ring is formed of aluminum oxide. 
         [0031]    It is to be understood that both the foregoing general description and the following detailed description of the present invention arc exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
           [0033]      FIG. 1  illustrates a related art electrostatic chucking apparatus; 
           [0034]      FIG. 2  illustrates an electrostatic chucking apparatus according to one embodiment of the present invention; 
           [0035]      FIG. 3  illustrates an electrostatic chucking apparatus according to another embodiment of the present invention; and 
           [0036]      FIGS. 4A to 41  are cross section views illustrating a method for manufacturing the electrostatic chucking apparatus according to the embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]    Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
         [0038]    Hereinafter, an electrostatic chucking apparatus according to the present invention and a method for manufacturing the same will be described with reference to the accompanying drawings. 
         [0039]      FIG. 2  illustrates an electrostatic chucking apparatus according to one embodiment of the present invention. 
         [0040]    Referring to  FIG. 2 , the electrostatic chucking apparatus according to one embodiment of the present invention includes a base member  200  and an electrostatic chuck  300 . 
         [0041]    The base member  200  is made of a metal material. For example, the base member  200  may be made of aluminum (Al). The base member  200  may include an additional extending portion onto which the electrostatic chuck  300  is loaded. 
         [0042]    The electrostatic chuck  300  includes an insulating member  310 , a heater  320 , a direct current electrode (DC electrode)  330 , and an insulator etch stopping layer  340 . 
         [0043]    The insulating member  310  may include first, second, and third insulating layers  312 ,  314 , and  316 . 
         [0044]    The first insulating layer  312  is deposited on the base member  200 . 
         [0045]    The second insulating layer  314  is deposited on the first insulating layer  312  under such circumstances that the heater  312  is interposed between the second insulating layer  314  and the first insulating layer  312 . 
         [0046]    The third insulating layer  316  is deposited on the second insulating layer  314  under such circumstances that the DC electrode  330  is interposed between the third insulating layer  316  and the second insulating layer  314 . 
         [0047]    Each of the first, second, and third insulating layers  312 ,  314 , and  316  is formed of at least one first insulating sheet  312   a  which is made of aluminum nitride (AIN) having a thermal conductivity of 90 W/mk or above. 
         [0048]    The heater  320  includes an internal heater  320   a  and an external heater  320   b,  wherein both the internal and external heaters  320   a  and  320   b  are positioned between the first and second insulating layers  312  and  314 . 
         [0049]    The internal heater  320   a  is formed in the central portion of the first insulating layer  312 . The internal heater  320   a  is heated by an externally-provided first heater source, and then the internal heater  320   a  heats the central portion of the electrostatic chuck  300  to a predetermined temperature. In this case, the internal heater  320   a  may be formed to have a concentric-circle shape. 
         [0050]    The external heater  320   b  is formed in the margin of the first insulating layer  312 . The external heater  320   b  is heated by an externally-provided second heater source, and then the external heater  320   b  heats the margin of the electrostatic chuck  300  to a predetermined temperature. In this case, the external heater  320   b  may be formed to have a concentric-circle shape outside the external heater  320   a.    
         [0051]    In order to realize a simplified process for manufacturing the electrostatic chuck  300 , each of the internal and external heaters  320   a  and  320   b  may be inserted into a heater insertion groove (not shown) which is formed at each corresponding portion on the surface of the first insulating layer  312 . 
         [0052]    The heater  320  including the separately-operable internal and external heaters  320   a  and  320   b  enables to realize a precise temperature control for the substrate, whereby a temperature can be selectively controlled on corresponding partial portions of the entire substrate, thereby realizing a uniform temperature gradient in the substrate. 
         [0053]    The DC electrode  330  is formed in an electrode sheet positioned on the second insulating layer  314 . The DC electrode  330  generates an electrostatic force by an externally-provided direct current, and the electrostatic force generated by the DC electrode  330  enables to chuck the substrate to the entire surface of the electrostatic chuck  300 . In order to realize a simplified process for manufacturing the electrostatic chuck  300 , the DC electrode  330  may be inserted into an electrode insertion groove (not shown) which is formed at a corresponding portion on the surface of the second insulating layer  314 . 
         [0054]    The DC electrode  330  and the insulating member  310  may be formed of materials which are similar in thermal expansions and qualities. For example, the DC electrode  330  may be made of titan (Ti), tungsten (W), or tantalum (Ta). The DC electrode  330  may be formed by any one method of pressurizing, screen printing, doctor blade, and tape casting. 
         [0055]    The insulator etch stopping layer  340  is formed on an entire surface of the third insulating layer  316 . Preferably, the insulator etch stopping layer  340  is made of a material which has a great thermal conductivity for efficiently transmitting the heat generated by the heater  320  to the substrate, and also has a high etch resistance by plasma. For this, the insulator etch stopping layer  340  is formed of at least one second insulating sheet of aluminum oxide (Al 2 O 3 ) having a thermal conductivity of 18 W/mk or above. The insulator etch stopping layer  340  may be formed on the third insulating layer  316  under high temperature and high pressure. In this case, the insulator etch stopping layer  340  is thinner than the insulating member  310  so as to realize the smooth electrostatic chucking and the good thermal conductivity for the substrate. For example, the insulator etch stopping layer  340  has a thickness of about 7 mm preferably. 
         [0056]    During or after a process for manufacturing a semiconductor device, the insulator etch stopping layer  340  can prevent the third insulating layer  316  from being etched by plasma (or etching gas) when cleaning a chamber by etching. 
         [0057]    The aforementioned electrostatic chucking apparatus according to the present invention discloses that the insulator etch stopping layer  340  of aluminum oxide is formed on the insulating member  310  of aluminum nitride so as to prevent the insulating member  310  from being etched by plasma. Accordingly, the aforementioned electrostatic chucking apparatus according to the present invention enables to extend the lifetime of the electrostatic chuck  300 , to reduce a maintenance cost owing to the extended period of replacing the electrostatic chuck  300 , and to improve the yield in process for manufacturing the semiconductor device. 
         [0058]    In the aforementioned electrostatic chucking apparatus according to the present invention, since the insulator etch stopping layer  340  is relatively thinner than the insulating member  310 , the heat generated by the heater  320  is uniformly transmitted to the insulating member  310  having the high thermal conductivity, thereby enabling the uniform surface temperature of the electrostatic chuck  300 . Also, the high thermal conductivity of the insulating member  310  enables to rapidly control heating and cooling of the electrostatic chuck  300 , so that it is possible to improve the yield in process for manufacturing the semiconductor device. 
         [0059]      FIG. 3  illustrates an electrostatic chucking apparatus according to another embodiment of the present invention, which includes an additionally-provided focus ring  400 . 
         [0060]    The focus ring  400 , which covers lateral sides of an electrostatic chuck  300 , is formed on a base member  200 . In this case, the focus ring  400  may be formed of the same material as that of an insulator etch stopping layer  340 . 
         [0061]    The focus ring  400  protects lateral sides of the insulator etch stopping layer  340  as well as lateral sides of an insulating member  310  from plasma. Even though the insulator etch stopping layer  340  protects the insulating member  310  of the electrostatic chuck  300 , the lateral sides of the insulating member  310  are exposed to plasma. In this respect, the focus ring  400  is provided to protect the lateral sides of the electrostatic chuck  300  from plasma. 
         [0062]    Also, the focus ring  400  is provided to concentrate plasma on a predetermined portion for loading the substrate during the process for manufacturing the semiconductor device using plasma. 
         [0063]      FIGS. 4A to 41  are cross section views illustrating a method for manufacturing the electrostatic chucking apparatus according to the embodiment of the present invention. 
         [0064]    A method for manufacturing the electrostatic chucking apparatus according to embodiment of the present invention will be explained with reference to  FIGS. 4A to 41 . 
         [0065]    First, as shown in  FIG. 4A , the first insulating layer  312  is formed of at least one first insulating sheet  312   a  of aluminum nitride. 
         [0066]    As shown in  FIG. 4B , the heater  320  including the internal and external heaters  320   a  and  320   b  is deposited on the first insulating layer  312 . 
         [0067]    At this time, the heater  320  includes the internal heater  320   a  and the external heater  320   b.  The internal heater  320   a  is formed at the central portion of the first insulating layer  312 , and the internal heater  320   a  is heated by the externally-provided first heater source. Also, the external heater  320   b  is formed in the margin of the first insulating layer  312 , and the external heater  320   b  is heated by the second heater source. In order to simplify the process for manufacturing the electrostatic chuck  300 , each of the internal and external heaters  320   a  and  320   b  may be inserted into the heater insertion groove (not shown) which is provided at each corresponding portion on the surface of the first insulating layer  312 . 
         [0068]    As shown in  FIG. 4C , the second insulating layer  314  is formed on the heater  320 , wherein the second insulating layer  314  is formed of at least one first insulating sheet  312   a.    
         [0069]    As shown in  FIG. 4D , the DC electrode  330  is formed on the second insulating layer  314 . For simplifying the process for manufacturing the electrostatic chuck  300 , the DC electrode  330  may be inserted into the electrode insertion groove (not shown) which is formed at the corresponding portion on the surface of the second insulating layer  314 . 
         [0070]    The DC electrode  330  may be formed on an additional electrode sheet positioned above the second insulating layer  314 . 
         [0071]    As shown in  FIG. 4E , the third insulating layer  316  is formed on the second insulating layer  314  under such circumstances that the DC electrode  330  is interposed between the third insulating layer  316  and the second insulating layer  314 , wherein the third insulating layer  316  is formed of at least one first insulating sheet  312   a.    
         [0072]    As shown in  FIG. 4F , the insulator etch stopping layer  340  is formed on the third insulating layer  316 , wherein the insulator etch stopping layer  340  is formed of at least one second insulating sheet of aluminum oxide. 
         [0073]    As shown in  FIG. 4G , the insulator etch stopping layer  340  and the first to third insulating layers  312 ,  314 , and  316  including the heater  320  and the DC electrode  330  are formed under the high temperature and high pressure, thereby manufacturing the electrostatic chuck  300 . 
         [0074]    As shown in  FIG. 4H , the manufactured electrostatic chuck  300  is loaded onto the base member  200 , thereby manufacturing the electrostatic chucking apparatus. 
         [0075]    In the method for manufacturing the electrostatic chucking apparatus according to the embodiment of the present invention, as shown in  FIG. 41 , the focus ring  400  covering the lateral sides of the electrostatic chuck  300  is formed on the base member  200 . At this time, the focus ring  400  may be made of the same material as that of the insulator etch stopping layer  340 . 
         [0076]    Accordingly, the electrostatic chucking apparatus according to the present invention and the method for manufacturing the same have the following advantages. 
         [0077]    As the insulator etch stopping layer  340  of aluminum oxide is formed on the insulating member  310  of aluminum nitride, it is possible to prevent the insulating member  310  from being etched by plasma. Thus, the increased lifetime of the electrostatic chuck  300  enables to extend the period of replacing the electrostatic chuck  300 , to reduce the maintenance cost, and to improve the yield in the process for manufacturing the semiconductor device. 
         [0078]    Since the insulator etch stopping layer  340  is relatively thinner than the insulating member  310 , the heat generated by the heater  320  is uniformly transmitted to the insulating member  310  having the high thermal conductivity, thereby enabling the uniform surface temperature of the electrostatic chuck  300 . Also, the high thermal conductivity of the insulating member  310  enables to rapidly control heating and cooling of the electrostatic chuck  300 , so that it is possible to improve the yield in process for manufacturing the semiconductor device. 
         [0079]    It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.