Patent Publication Number: US-2013240492-A1

Title: Apparatus For Generating Hollow Cathode Plasma And Apparatus For Treating Large Area Substrate Using Hollow Cathode Plasma

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This non-provisional application is a divisional under 35 U.S.C. 121 of U.S. application Ser. No. 12/457,280, filed on Jun. 5, 2009, which claims priority under 35 U.S.C. §119 to Korean Application No. 10-2008-0067664, filed on Jul. 11, 2008, the entire contents of each of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     The present disclosure relates to an apparatus for treating a substrate using plasma, and more particularly, to an apparatus for generating hollow cathode plasma and an apparatus for treating a large area substrate using the hollow cathode plasma, in which ashing, cleaning, and etching processes can be performed on a substrate such as a semiconductor wafer or a glass substrate using the plasma. 
     In general, various processes such as an etching process, an ashing process, and a cleaning process are required in order to manufacture a semiconductor device. Recently, the above-described processes are being performed using plasma. 
     An inductively coupled plasma source and a remote plasma source are being selectively used as a plasma source. 
       FIG. 1  is a cross-sectional view of an inductively coupled plasma (ICP) dry etching apparatus. In an ICP method, when a circular or spiral antenna  12  is installed on a chamber  11  and a high frequency power  13  is applied to the antenna  12 , a current flows along a coil to generate an electric field around the coil. As a result, an induced electric field is generated inside the chamber  11  due to the electric field, and electrons are accelerated to generate plasma. 
     According to the ICP method, the plasma may be generated at a very low pressure, and thus, it is a great advantage to etch a fine pattern. In addition, a bias power  14  may be applied to a wafer electrode to very finely adjust an etching rate. 
     However, it is difficult to control a radical density at a high pressure in the ICP method. Thus, the fine pattern formation process may be performed at only a low pressure. 
     In recent, as a semiconductor substrate increases in size, it is required to uniformly distribute a process gas on the substrate. However, it is difficult to etch a large area and control plasma at a high pressure in a plasma etching apparatus using an inductively coupled plasma source. 
       FIG. 2  is a cross-sectional view of a remote plasma ashing apparatus. Referring to  FIG. 2 , in a remote plasma ashing apparatus, a remote plasma generator  22  is installed in a reaction gas inlet port disposed outside a chamber  21 . Due to the remote plasma generator  22 , energy is provided to a reaction gas to activate the reaction gas. The activated reaction gas is injected into the chamber  21  through a gas injection tube  23  to perform deposition and etching processes. 
     It is difficult to treat a large area substrate, and a plasma density is low in the ashing apparatus using such a remote plasma source. 
     SUMMARY 
     The present disclosure provides an apparatus for generating hollow cathode plasma. 
     The present disclosure also provides an apparatus for treating a large area substrate using hollow cathode plasma, in which a substrate treatment process can be efficiently performed using plasma. 
     The present disclosure also provides an apparatus for treating a large area substrate using hollow cathode plasma, in which a plasma density can increase. 
     The present disclosure also provides an apparatus for treating a large area substrate using hollow cathode plasma, in which plasma uniformity can be improved. 
     The object of the present disclosure is not limited to the aforesaid, but other objects not described herein will be clearly understood by those skilled in the art from descriptions below. 
     Embodiments of the present disclosure provide apparatuses for generating hollow cathode plasma including: a hollow cathode in which a plurality of lower grooves where plasma is generated is defined in a bottom surface thereof; an electrode disposed to be spaced from the hollow cathode; and a power supply source connected to at least one of the hollow cathode and the electrode, wherein an inflow hole passing and extending from an upper end of each of the lower grooves up to a top surface of the hollow cathode is defined in a portion of the lower grooves. 
     In some embodiments, the inflow hole may be tapered so that the inflow hole gradually increases in cross-sectional area from a lower portion toward an upper portion. 
     In other embodiments, each of the lower grooves may be tapered so that the lower groove gradually increases in cross-sectional area from an upper portion toward a lower portion. 
     In still other embodiments, the inflow hole may be provided in only the portion of the lower grooves. 
     In even other embodiments, the lower grooves in which the inflow hole is provided among the lower grooves may be respectively disposed between the lower grooves in which the inflow hole is not provided. 
     In other embodiments of the present disclosure, apparatuses for treating a large area substrate using hollow cathode plasma include: a process chamber for providing a space in which a substrate treatment process is performed, the process chamber including an exhaust hole for exhausting a gas; a gas supply member for supplying the gas into the process chamber; a substrate support member disposed inside the process chamber, the substrate support member supporting the substrate; a hollow cathode in which a plurality of lower grooves where plasma is generated is defined in a bottom surface thereof, the hollow cathode being disposed inside the process chamber; a baffle in which a plurality of injection holes is defined, the baffle being disposed below the hollow cathode; and a power supply source for applying a power to the hollow cathode. 
     In some embodiments, the substrate support member may further include a lower electrode, and the power supply source may apply the power to at least one of the hollow cathode, the lower electrode, and the baffle. 
     In other embodiments, the hollow cathode may further include an inflow hole extending from an upper end of each of the lower grooves to pass up to a top surface of the hollow cathode. 
     In still other embodiments, each of the lower grooves may have a cross-sectional area greater than that of the inflow hole. 
     In even other embodiments, the inflow hole may have a circular section and a diameter ranging from about 0.5 mm to about 3 mm. 
     In yet other embodiments, the inflow hole may be tapered so that the inflow hole gradually increases in cross-sectional area from a lower portion toward an upper portion. 
     In further embodiments, each of the lower grooves may be tapered so that the lower groove gradually increases in cross-sectional area from an upper portion toward a lower portion. 
     In still further embodiments, each of the lower grooves may have a circular section, a diameter ranging from about 1 mm to about 10 mm, and a height ranging from once to twice its diameter. 
     In even further embodiments, the inflow hole may be provided in only a portion of the lower grooves. 
     In yet further embodiments, the lower grooves in which the inflow hole is provided among the lower grooves may be respectively disposed between the lower grooves in which the inflow hole is not provided. 
     In yet further embodiments, the hollow cathode may be coated with any one of an oxide layer, a nitride layer, and a dielectric coating. 
     In yet further embodiments, the power supply source may be respectively connected to the hollow cathode and the lower electrode, and the baffle may be grounded. 
     In yet further embodiments, the hollow cathode may be disposed in an inner upper portion of the process chamber, the baffle may be disposed below the hollow cathode, the gas supply member may be disposed in a lateral surface of the process chamber to supply the gas between the hollow cathode and the baffle, and the substrate support member may be disposed below the baffle. 
     In yet further embodiments, the gas supply member may be disposed in an inner upper portion of the process chamber, the hollow cathode may be disposed below the gas supply member, the baffle may be disposed below the hollow cathode, and the substrate support member is disposed below the baffle. 
     In still other embodiments of the present disclosure, apparatuses for treating a large area substrate using hollow cathode plasma include: a process chamber for providing a space in which a substrate treatment process is performed; a gas inflow part for introducing a gas into the process chamber; a first plasma generating part for discharging the gas by a hollow cathode effect to generate plasma; and a second plasma generating part for equalizing a density of the gas passing through the first plasma generating part. 
     In some embodiments, the first plasma generating part may include a hollow cathode in which a power is applied and a plurality of lower grooves is defined in a bottom surface thereof. 
     In other embodiments, the second plasma generating part may include a baffle in which a plurality of injection holes is defined and a lower electrode provided in a substrate support member on which the substrate is mounted. 
     In still other embodiments, the hollow cathode may further include an inflow hole extending from an upper end of each of the lower grooves to pass up to a top surface of the hollow cathode. 
     In even other embodiments, each of the lower grooves may have a cross-sectional area greater than that of the inflow hole. 
     In yet other embodiments, the inflow hole may have a circular section and a diameter ranging from about 0.5 mm to about 3 mm. 
     In further embodiments, the inflow hole may be tapered so that the inflow hole gradually increases in cross-sectional area from a lower portion toward an upper portion. 
     In still further embodiments, each of the lower grooves may be tapered so that the lower groove gradually increases in cross-sectional area from an upper portion toward a lower portion. 
     In even further embodiments, the inflow hole may be provided in only a portion of the lower grooves. 
     In yet further embodiments, the lower grooves in which the inflow hole is provided among the lower grooves may be respectively disposed between the lower grooves in which the inflow hole is not provided. 
     In even other embodiments of the present disclosure, apparatuses for treating a large area substrate using hollow cathode plasma include: a process chamber for providing a space in which a substrate treatment process is performed, the process chamber including an exhaust hole for exhausting a gas; a gas supply member for supplying the gas into the process chamber; a substrate support member disposed in an lower portion of the process chamber, the substrate support member supporting the substrate; a hollow cathode in which a plurality of lower grooves where plasma is generated is defined in a bottom surface thereof, the hollow cathode being disposed in an upper portion of the process chamber; a lower electrode provided in the substrate support member; and a power supply source for respectively applying a power to the hollow cathode and the lower electrode. 
     In some embodiments, the hollow cathode may further include an inflow hole extending from an upper end of each of the lower grooves to pass up to a top surface of the hollow cathode. 
     In other embodiments, each of the lower grooves may have a cross-sectional area greater than that of the inflow hole. 
     In still other embodiments, the inflow hole may be tapered so that the inflow hole gradually increases in cross-sectional area from a lower portion toward an upper portion. 
     In even other embodiments, each of the lower grooves may be tapered so that the lower groove gradually increases in cross-sectional area from an upper portion toward a lower portion. 
     In yet other embodiments, the inflow hole may be provided in only a portion of the lower grooves. 
     In further embodiments, the lower grooves in which the inflow hole is provided among the lower grooves may be respectively disposed between the lower grooves in which the inflow hole is not provided. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The accompanying figures are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate example embodiments and, together with the description, serve to explain principles of the present disclosure. In the figures: 
         FIG. 1  is a cross-sectional view of an inductively coupled plasma etching apparatus; 
         FIG. 2  is a cross-sectional view of a remote plasma ashing apparatus; 
         FIG. 3  is a cross-sectional view of a hollow cathode plasma generator according to the present disclosure; 
         FIG. 4  is a cross-sectional view of an apparatus for treating a large area substrate using hollow cathode plasma according to a first embodiment of the present disclosure; 
         FIG. 5  is a cross-sectional view of an apparatus for treating a large area substrate using hollow cathode plasma according to a second embodiment of the present disclosure; 
         FIG. 6  is a cross-sectional view of an apparatus for treating a large area substrate using hollow cathode plasma according to a third embodiment of the present disclosure; 
         FIG. 7  is a cross-sectional view of an apparatus for treating a large area substrate using hollow cathode plasma according to a fourth embodiment of the present disclosure; 
         FIG. 8  is a cross-sectional view of an apparatus for treating a large area substrate using hollow cathode plasma according to a fifth embodiment of the present disclosure; and 
         FIGS. 9A to 9D  are cross-sectional views of a hollow cathode according to embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments of the present disclosure will be described below in more detail with reference to the accompanying drawings. The present disclosure may, however, be embodied in different forms and should not be constructed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. In the figures, the shapes of the elements may have been exaggerated to facilitate an understanding of the present disclosure. 
     A hollow cathode plasma generator according to the present disclosure will now be described. 
       FIG. 3  is a cross-sectional view of a hollow cathode plasma generator according to the present disclosure. Referring to  FIG. 3 , a hollow cathode plasma generator includes a hollow cathode  40 , an electrode  50 , and power supply sources  61  and  62 . 
     The hollow cathode  40  has a circular plate shape. A plurality of lower grooves  41  and a plurality of inflow holes  42  are defined in the hollow cathode  40 . 
     The lower grooves  41  are defined in a bottom surface of the hollow cathode  40 . The lower grooves  41  are spaces in which plasma is generated by a hollow cathode effect. The inflow holes  42  extending from an upper end of each of the lower grooves  41  and passing up to a top surface of the hollow cathode  40  is defined in the lower grooves  41 , respectively. 
     Although details are described later, each of the inflow holes  42  may be tapered so that the inflow hole  42  gradually increases in cross-sectional area from a lower portion toward an upper portion. Each of the lower grooves  41  may be tapered so that the lower groove  41  gradually increases in cross-sectional area from an upper portion toward a lower portion. Also, the inflow holes  42  may be provided in only a portion of the lower grooves  41 . The lower grooves  41  in which the inflow holes  42  are provided may be disposed between the lower grooves  41  in which the inflow holes  42  are not provided, respectively. 
     The electrode  50  is spaced from the hollow cathode  40 . A heater  51  may be provided inside the electrode  50  to heat the substrate. 
     The power supply sources  61  and  62  are connected to at least one of the hollow cathode  40  and the electrode  50  to supply a power thereto. Specifically, a frequency of the power applied to the hollow cathode  40  of the present disclosure may be used at a frequency ranging from several hundred kHz up to several ten MHz. 
     An apparatus for treating a large area substrate using hollow cathode plasma according to the present disclosure will be described below. 
     The apparatus for treating the large area substrate using the hollow cathode plasma according to the present disclosure may be applicable to various processes such as an etching process, an ashing process, a cleaning process, and a surface modification process using the plasma. For reference, first to fourth embodiments of the present disclosure relate to a remote plasma source, and a fifth embodiment relates to an in-situ plasma source. 
     An apparatus for treating a large area substrate using hollow cathode plasma according to a first embodiment of the present invention will now be described. 
       FIG. 4  is a cross-sectional view of an apparatus for treating a large area substrate using hollow cathode plasma according to a first embodiment of the present disclosure. Referring to  FIG. 4 , a substrate treatment apparatus  100  of the present disclosure includes a process chamber  110 , a gas supply member  120 , a substrate support member  130 , a hollow cathode  140 , a baffle  150 , and a power supply source  170 . 
     The process chamber  110  provides a space in which a substrate treatment process is performed. An exhaust hole  111  for exhausting gases is defined in a bottom surface of process chamber  110 . The exhaust hole  111  is connected to an exhaust line in which a pump is installed to exhaust reaction by-products generated inside the process chamber  110  and maintain a process pressure in the process chamber  110 . The gas supply member  120  supplies gases required for the substrate treatment process into the process chamber  110 . 
     The substrate support member  130  supports a substrate W and is disposed inside the process chamber  110 . The substrate support member  130  may include an electrostatic chuck and a mechanical chuck. According to the first embodiment, a heater  160  may be provided such that the substrate support member  130  can serve as a heating chuck. The power supply source  170  supplies a power to only the hollow cathode  140 , and it is not necessary to supply a separate power to the substrate support member  130 . 
     The substrate support member  130  may be selectively fixed or rotate or be vertically moved with respect to a horizontal surface. The substrate support member  130  includes a support plate  131 , a drive shaft  132 , and a driver  133  to support the substrate W. The substrate W is disposed on the support plate  131  and parallel to the support plate  131 . The drive shaft  132  has one end connected to a lower portion of the support plate  131  and the other end connected to the driver  133 . 
     A rotation force generated by the driver  133  is transmitted to the drive shaft  132 , and the drive shaft  132  rotates together with the support plate  131 . 
     The hollow cathode  140  is disposed inside the process chamber  110 . A plurality of lower grooves  141  in which plasma is generated is defined in a bottom surface of the hollow cathode  140 . 
     The baffle  150  is spaced from the hollow cathode  150 . A plurality of injection holes  151  is defined in the baffle  150 . 
     The gas supply member  120  is disposed above the process chamber  110 . The hollow cathode  140  is disposed below the gas supply member  120 , and the baffle  150  is disposed below the hollow cathode  140 . The substrate support member  130  is disposed below the baffle  150 . 
     The gas supply member  120  supplies a gas toward the hollow cathode  140 . At this time, the hollow cathode  140  functions as a cathode electrode, and the baffle  150  functions as an anode electrode. The introduced gas is discharged by a hollow cathode effect through the hollow cathode  140  to generate the plasma. 
     The generated plasma is injected through the injection holes  151  of the baffle  150 . The injected plasma reacts with the substrate W heated by the heating chuck  160  to perform the substrate treatment process. The heating chuck  160  may be heated at a temperature of about 250° C. 
     In case where the process chamber  110  has a generally cylindrical shape, the hollow cathode  140  and the baffle  150  may have circular plate shapes, respectively. To generate the plasma, a distance d 1  spaced between the hollow cathode  140  and the baffle  150  may range from about 10 mm to about 100 mm. The hollow cathode  140  is coated with any one of an oxide layer, a nitride layer, and a dielectric coating. 
     According to the first embodiment, the supplied gas is discharged in the lower grooves  141  defined in the hollow cathode  140  by the hollow cathode effect to generate the plasma, and reaction plasma in which a density of the gas passing through the hollow cathode  140  is uniform is generated by the baffle  150 . 
     Hereinafter, an operation of the baffle  150  will be described. 
     Two elements with respect to a process using the plasma among elements contained in the plasma generated by the hollow cathode  140  are free radicals and ions. The free radicals have an incomplete bonding and are electroneutrality. Thus, the free radicals have a very high reactivity due to the incomplete bonding. The free radicals perform a process through mainly chemical reaction with a material disposed on the substrate W. However, since the ions have an electric charge, the ions are accelerated in a certain direction according to an electric potential difference. Thus, the ions perform a process through mainly physical reaction with the material disposed on the substrate W. 
     The free radicals and the ions are contained also in the plasma generated by the hollow cathode  140 . The free radicals are moved toward an upper portion of the substrate W to chemically react with a resist disposed on the substrate W. On the other hand, the ions having a predetermined electric charge are accelerated toward the substrate W to collide with the resist disposed on the substrate W, and thus to physically react with the resist. At this time, in case where the ions accelerated toward the substrate W collide with patterns of the resist, the fine patterns may be damaged due to the collision. The patterns disposed on the substrate W has a previously set electric charge for a next process. However, in case where the ions collide with the patterns of the substrate W, an amount of the previously set electric charge may be changed to have an effect on the next process. 
     The baffle  150  prevents the amount of the previously set electric charge from being changed. The free radicals of the plasma moved toward an upper portion of the baffle  150  are moved onto the substrate W through the injection holes  151  defined in the baffle  150 . On the other hand, since the ions are blocked by the grounded baffle  150 , the ions are not moved onto the substrate W. Thus, since only the free radicals of the plasma reach onto the substrate W, it can prevent the patterns of the substrate W from being damaged by the ions. 
     The baffle  150  may be formed of a metal material or formed by coating the metal material with a nonmetal material. For example, the baffle  150  may be formed of an aluminum material or an anodized aluminum material. The baffle  150  includes the plurality of injection holes  151  disposed to be spaced a predetermined distance from each other on a concentric circumference in order to uniformly supply the radicals. In case where each of the plurality of injection holes  151  defined in the baffle  150  has a circular shape in section, the injection hole  151  has a diameter ranging from about 0.5 mm to about 3 mm. The baffle  150  is fixed to the upper portion of the process chamber  110  by a plurality of coupling members such as bolts at an edge portion thereof. As described above, the high frequency power is applied to the hollow cathode  140 , and the baffle  150  is grounded. The plasma generated in the hollow cathode  140  passes through the injection holes  151  defined in the baffle  150  and is moved toward the substrate W disposed on the substrate support member  130 . At this time, the charged particles such as electrons or ions are not introduced toward a lower portion of the baffle  150  by the baffle  150  formed of the aluminum material or the anodized aluminum material. Only neutral particles that do not have the electric charge such as oxygen radicals reach the substrate W disposed on the substrate support member  130  to treat the substrate W according to their purpose. 
     Hereinafter, the hollow cathode  140  according to embodiments will be described with reference to  FIGS. 9A to 9D . 
     Referring to  FIG. 9 , the hollow cathode  140  further includes inflow holes  142  extending from an upper end of each of the lower grooves  141  and passing up to a top surface thereof. Each of the lower grooves  141  has a cross-sectional area wider than that of each of the inflow holes  142 . 
     That is, in case where the lower groove  141  has a circular section, the circular section has a diameter ranging from about 1 mm to about 10 mm. The lower groove  141  may have a height ranging from once to twice its diameter. 
     Also, in case where the inflow hole  142  has a circular section, the inflow hole  142  may have a diameter d 2  ranging from about 0.5 mm to about 3 mm such that the inflow hole  142  does not have an effect on the hollow cathode effect. 
     Although the lower groove  141  and the inflow hole  142  have the circular sections, respectively, the present disclosure is not limited thereto. For example, the lower groove  141  and the inflow hole  142  may have various sectional shapes, respectively. 
     Referring to  FIG. 9B , the hollow cathode  140  includes the plurality of lower grooves  141 . The inflow holes  142  extending from an upper end of each of the lower grooves and passing up to a top surface thereof are provided in a portion of the lower grooves  141 , respectively. At this time, lower grooves  141   b  in which the inflow holes  142  are respectively provided are disposed between the lower grooves  141   a  in which the inflow holes  142  are not provided, respectively. 
     The gas introduced through the previously described gas supply member  120  is plasma-discharged firstly in the lower grooves  141   b  in which the inflow holes  142  are respectively provided. Thereafter, the gas introduced through the gas supply member  120  is plasma-discharged in the lower grooves  141   a  in which the inflow holes  142  are not provided. 
     Each of the lower grooves  141  has a cross-sectional area wider than that of each of the inflow holes  142 . In case where the lower groove  141  has a circular section, the circular section has a diameter ranging from about 1 mm to about 10 mm. The lower groove  141  may have a height ranging from once to twice its diameter. 
     Also, in case where the inflow hole  142  has a circular section, the inflow hole  142  may have a diameter d 2  ranging from about 0.5 mm to about 3 mm such that the inflow hole  142  does not have an effect on the hollow cathode effect. 
     Although the lower groove  141  and the inflow hole  142  have the circular sections, respectively, the present disclosure is not limited thereto. For example, the lower groove  141  and the inflow hole  142  may have various sectional shapes, respectively. Referring to  FIG. 9C , the inflow hole  142  may be tapered so that the inflow hole  42  gradually increases in cross-sectional area from a lower portion toward an upper portion, thereby easily introducing the gas through the inflow hole  142 . 
     Referring to  FIG. 9D , the lower groove  141  may be tapered so that the lower groove  141  gradually increases in cross-sectional area from an upper portion toward a lower portion, thereby widely spreading the generated plasma. 
     Of course, the configurations of the lower groove  141  and the inflow hole  142  may be variously combined with each other. 
     An apparatus for treating a large area substrate using hollow cathode plasma according to a second embodiment of the present disclosure will now be described. 
       FIG. 5  is a cross-sectional view of an apparatus for treating a large area substrate using hollow cathode plasma according to a second embodiment of the present disclosure. Referring to  FIG. 5 , an apparatus  200  for treating a large area substrate using hollow cathode plasma of the present disclosure includes a process chamber  210 , a gas supply member  220 , a substrate support member  230 , a hollow cathode  240 , a baffle  250 , a lower electrode  260 , and power supply sources  271  and  272 . 
     The process chamber  210  provides a space in which a substrate treatment process is performed. An exhaust hole  211  for exhausting gases is defined in a bottom surface of process chamber  210 . The exhaust hole  211  is connected to an exhaust line in which a pump is installed to exhaust reaction by-products generated inside the process chamber  210  and maintains a process pressure in the process chamber  210 . The gas supply member  220  supplies gases required for the substrate treatment process into the process chamber  210 . 
     The substrate support member  230  supports a substrate W and is disposed inside the process chamber  210 . The lower electrode  260  is provided in the substrate support member  230  and may further include an electrostatic chuck and a mechanical chuck. 
     The substrate support member  230  may be selectively fixed or rotate or be vertically moved with respect to a horizontal surface. The substrate support member  230  includes a support plate  231 , a drive shaft  232 , and a driver  233  to support the substrate W. The substrate W is disposed on the support plate  231  and parallel to the support plate  231 . The drive shaft  232  has one end connected to a lower portion of the support plate  231  and the other end connected to the driver  233 . A rotation force generated by the driver  233  is transmitted to the drive shaft  232 , and the drive shaft  132  rotates together with the support plate  231 . 
     The hollow cathode  240  is disposed inside the process chamber  210 . A plurality of lower grooves  241  in which plasma is generated is defined in a bottom surface of the hollow cathode  240 . 
     The baffle  250  is spaced from the hollow cathode  250 . A plurality of injection holes  251  is defined in the baffle  250 . Unlike the first embodiment, the substrate treatment apparatus  200  includes the upper power supply source  271  and the lower power supply source  272  in the second embodiment. The upper power supply source  271  applies a power to the hollow cathode  240 , and the lower power supply source  272  applies the power to the lower electrode  260 . 
     The gas supply member  220  is disposed above the process chamber  210 . The hollow cathode  240  is disposed below the gas supply member  220 , and the baffle  250  is disposed below the hollow cathode  240 . The substrate support member  230  is disposed below the baffle  250 . 
     The gas supply member  220  supplies a gas to a gas inflow portion A. The gas inflow portion A is a space between a top surface of the process chamber and the hollow cathode  240  disposed in an inner upper portion of the process chamber  210  as illustrated in  FIG. 3 . 
     A space between the hollow cathode  240  and the baffle  250  refers to as a first plasma generating portion B. At this time, the hollow cathode  240  functions as a cathode electrode, and the baffle  250  functions as an anode electrode. The gas introduced into the gas inflow portion A is discharged by the hollow cathode effect through the hollow cathode  240  to generate plasma. The first plasma generating portion B includes spaces provided by the lower grooves  241  of the hollow cathode  240  and the space between the hollow cathode  240  and the baffle  250 . 
     A space between the baffle  250  and the substrate support member  230  refers to as a second plasma generating portion C. The plasma gas generated in the first plasma generating portion B is generated again by the baffle  250  and the lower electrode  260  (This is an important difference that distinguishes the second embodiment from the first embodiment). At this time, a plasma density of the gas passing through the first plasma generating portion B is further high and uniform in the second plasma generating portion C. 
     In case where the process chamber  210  has a generally cylindrical shape, the hollow cathode  240  and the baffle  250  may have circular plate shapes, respectively. To generate the plasma, a distance d 1  spaced between the hollow cathode  240  and the baffle  250  may range from about 10 mm to about 100 mm. The hollow cathode  240  is coated with any one of an oxide layer, a nitride layer, and a dielectric coating. 
     According to the second embodiment, the supplied gas is discharged in the lower grooves  241  defined in the hollow cathode  240  by the hollow cathode effect to generate the plasma, and reaction plasma in which a density of the gas passing through the hollow cathode  240  is uniform is generated by an operation of the baffle  250  and the lower electrode  260  serving as a capacitive coupled plasma (CCP) source. 
     As described above, the high frequency power is applied to the hollow cathode  240  and the lower electrode  260 , and the baffle  250  is grounded. The plasma generated in the hollow cathode  240  passes through the injection holes  251  defined in the baffle  250  and is moved toward the substrate W disposed on the substrate support member  230 . At this time, by an above-described additional function of the baffle  250 , the charged particles such as electrons or ions are not introduced into the second plasma generating portion C by the baffle  250  formed of an aluminum material or an anodized aluminum material. Only neutral particles that do not have the electric charge such as oxygen radicals reach the substrate W disposed on the substrate support member  230  to treat the substrate W according to their purpose. 
     Since a configuration of the hollow cathode  240  according to the second embodiment is equal to that of the hollow cathode  140  of the first embodiment described with reference to  FIGS. 9A and 9D , duplicate descriptions will be omitted. 
     An apparatus for treating a large area substrate using hollow cathode plasma according to a third embodiment of the present disclosure will now be described. 
       FIG. 6  is a cross-sectional view of an apparatus for treating a large area substrate using hollow cathode plasma according to a third embodiment of the present disclosure. Referring to  FIG. 6 , an apparatus  300  of treating a large area substrate using hollow cathode plasma includes a process chamber  310 , a gas supply member  320 , a substrate support member  330 , a hollow cathode  340 , a baffle  350 , a lower electrode  360 , and power supply sources  371  and  372 . 
     The process chamber  310  provides a space in which a substrate treatment process is performed. 
     An exhaust hole  311  for exhausting gases is defined in a bottom surface of process chamber  310 . The gas supply member  320  supplies the gases into the process chamber  310 . 
     The substrate support member  330  supports a substrate W, and the lower electrode  260  is provided inside the substrate support member  330 . A configuration of the substrate support member  330  according to this embodiment is equal to that of the substrate support member  230  according to the second embodiment. The substrate support member  330  is disposed in an inner lower portion of the process chamber  310 . The hollow cathode  340  is disposed in an inner upper portion of the process chamber  310 . A plurality of lower grooves  341  in which plasma is generated is defined in a bottom surface of the hollow cathode  340 . 
     The baffle  350  is spaced from the hollow cathode  350  and disposed above the substrate support member  330 . A plurality of injection holes  351  is defined in the baffle  350 . The upper power supply source  371  applies a power to the hollow cathode  340 , and the lower power supply source  372  applies the power to the lower electrode  360 . 
     The gas supply member  320  is disposed in a lateral surface of the process chamber  310  to supply a gas between the hollow cathode  340  and the baffle  350 . 
     According to the third embodiment, the supplied gas is discharged in the lower grooves  341  defined in the hollow cathode  340  by a hollow cathode effect to generate plasma, and reaction plasma in which a density of the gas passing through the hollow cathode  340  is uniform is generated due to an operation of the baffle  350  and the lower electrode  360  serving as a CCP source. 
     Since a configuration of the baffle  350  according to this embodiment is equal to that of the baffle  250  according to the second embodiment, duplicate descriptions will be omitted. 
     The lower grooves  341  defined in the hollow cathode  340  serve as places in which the gas introduced through the gas supply member  320  is plasma-discharged. Unlike the first and second embodiments, in the third embodiment, since the gas flows from the lateral surface of the process chamber  310 , separate injection holes need not be provided in the lower grooves  341 . In case where each of the lower grooves  341  has a circular section, the circular section has a diameter ranging from about 1 mm to about 10 mm. Also, each of the lower grooves  341  may have a height ranging from once to twice its diameter. Although the lower grooves  341  have the circular sections, respectively, the present disclosure is not limited thereto. For example, the lower grooves  341  may have various sectional shapes, respectively. The lower groove  341  may be tapered so that the lower groove  341  gradually increases in cross-sectional area from an upper portion toward a lower portion. The hollow cathode  340  is coated with any one of an oxide layer, a nitride layer, and a dielectric coating. 
     The hollow cathode  340  and the baffle  350  may have circular plate shapes, respectively. A distance d 1  spaced between the hollow cathode  340  and the baffle  350  may range from about 10 mm to about 100 mm. 
     An apparatus for treating a large area substrate using hollow cathode plasma according to a fourth embodiment of the present disclosure will now be described. 
       FIG. 7  is a cross-sectional view of an apparatus for treating a large area substrate using hollow cathode plasma according to a fourth embodiment of the present disclosure. Referring to  FIG. 7 , an apparatus  400  of treating a large area substrate using hollow cathode plasma includes a process chamber  410 , first and second gas supply members  420  and  420 ′, a substrate support member  430 , a hollow cathode  440 , a baffle  450 , a lower electrode  460 , and power supply sources  471  and  472 . 
     The process chamber  410  provides a space in which a substrate treatment process is performed. An exhaust hole  411  for exhausting gases is defined in a bottom surface of process chamber  410 . The first and second gas supply members  420  supply the gases into the process chamber  410 . 
     The substrate support member  430  supports a substrate W and is disposed inside the process chamber  410 . A configuration of the substrate support member  430  according to this embodiment is equal to that of the substrate support member  230  according to the second embodiment. The hollow cathode  440  is disposed inside the process chamber  410 . A plurality of lower grooves  441  in which plasma is generated is defined in a bottom surface of the hollow cathode  440 . 
     The baffle  450  is spaced from the hollow cathode  450 . A plurality of injection holes  451  is defined in the baffle  450 . The lower electrode  460  is provided in the substrate support member  430 . The upper power supply source  471  applies a power to the hollow cathode  440 , and the lower power supply source  472  applies the power to the lower electrode  460 . 
     In the fourth embodiment, the gas supply member includes the first gas supply member  420  disposed in an inner upper portion of the process chamber  410  and the second gas supply member  420 ′ disposed in a lateral surface of the process chamber  410  to supply the a gas between the hollow cathode  440  and the baffle  450 . The hollow cathode  440  is disposed below the first gas supply member  420 , and the baffle  450  is disposed below the hollow cathode  440 . The substrate support member  430  is disposed below the baffle  450 . 
     Similarly to the first embodiment, the hollow cathode  440  and the baffle  450  may have circular plate shapes, respectively. A distance d 1  spaced between the hollow cathode  440  and the baffle  450  may range from about 10 mm to about 100 mm. The hollow cathode  440  is coated with any one of an oxide layer, a nitride layer, and a dielectric coating. 
     Since configurations of the hollow cathode  440  and the baffle  450  according to this embodiment are similar to those of the hollow cathode  140  according to the first embodiment and the baffle  250  according to the second embodiment, duplicate descriptions will be omitted. 
     An apparatus for treating a large area substrate using hollow cathode plasma according to a fifth embodiment of the present disclosure will now be described. 
       FIG. 8  is a cross-sectional view of an apparatus for treating a large area substrate using hollow cathode plasma according to a fifth embodiment of the present disclosure. Referring to  FIG. 8 , an apparatus  500  of treating a large area substrate using hollow cathode plasma of the present disclosure includes a process chamber  510 , a gas supply member  520 , a substrate support member  530 , a hollow cathode  540 , a lower electrode  560 , and power supply sources  571  and  572 . 
     The process chamber  510  provides a space in which a substrate treatment process is performed. An exhaust hole  511  for exhausting gases is defined in a bottom surface of process chamber  510 . The exhaust hole  511  is connected to an exhaust line in which a pump is installed to exhaust reaction by-products generated inside the process chamber  510  and maintains a process pressure in the process chamber  510 . The gas supply member  520  supplies gases required for the substrate treatment process into the process chamber  510 . 
     The substrate support member  530  supports a substrate W and is disposed inside the process chamber  510 . The lower electrode  560  is provided in the substrate support member  530  and may further include an electrostatic chuck and a mechanical chuck. Of course, a heater  561  may be further provided inside the substrate support member  530  as necessary. 
     The substrate support member  530  may be selectively fixed or rotate or be vertically moved with respect to a horizontal surface. The substrate support member  530  includes a support plate  531 , a drive shaft  532 , and a driver  533  to support the substrate W. 
     The hollow cathode  540  is disposed inside the process chamber  510 . A plurality of lower grooves  541  in which plasma is generated is defined in a bottom surface of the hollow cathode  540 . 
     Unlike the first to fourth embodiments, a baffle is not provided in the fifth embodiment. The upper power supply source  571  applies a power to the hollow cathode  540 , and the lower power supply source  572  applies the power to the lower electrode  560 . 
     The gas supply member  520  is disposed above the process chamber  510 . The hollow cathode  540  is disposed below the gas supply member  520 , and the substrate support member  530  is disposed in an inner lower portion of the process chamber  510 . 
     The gas supply member  520  supplies a gas to the hollow cathode  540 . The gas introduced from the gas supply member  520  is discharged by a hollow cathode effect through the hollow cathode  540  to generate plasma. 
     In case where the process chamber  510  has a generally cylindrical shape, the hollow cathode  540  has a circular plate shape. The hollow cathode  540  is coated with any one of an oxide layer, a nitride layer, and a dielectric coating. 
     According to the fifth embodiment, the supplied gas is discharged in the lower grooves  541  defined in the hollow cathode  540  by the hollow cathode effect to generate the plasma. 
     Since a configuration of the hollow cathode  540  according to the fifth embodiment is equal to that of the hollow cathode  140  of the first embodiment described with reference to  FIGS. 9A and 9D , duplicate descriptions will be omitted. 
     According to the method of generating the hollow cathode plasma and the method of treating the large area substrate using the hollow cathode plasma, the plasma having the high density can be provided by the hollow cathode effect due to the hollow cathode in which the lower grooves are defined. 
     The plasma can be generated with two times by the hollow cathode and the injection holes of the baffle to provide the uniform plasma having the high density. 
     Since the plasma can be uniformly provided over a large area, it can be applicable to the semiconductor process for treating the large area substrate. 
     The above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true spirit and scope of the present disclosure. Thus, to the maximum extent allowed by law, the scope of the present disclosure is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.