Patent Publication Number: US-2022223384-A1

Title: Apparatus for manufacturing a semiconductor device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 USC § 119 to Japanese Patent Application No. 2021-004114, filed on Jan. 14, 2021 and Korean Patent Application No. 10-2021-0117507, filed on Sep. 3, 2021 in the Korean Intellectual Property Office (KIPO), the contents of which are herein incorporated by reference in their entirety. 
     BACKGROUND 
     1. Field 
     Example embodiments relate to an apparatus for manufacturing a semiconductor device. 
     2. Description of the Related Art 
     A plasma-processing apparatus for manufacturing a semiconductor device may function to etch with a high etching rate or a high etching selectivity by maintaining a low temperature of a wafer. For example, a relation between an etching selectivity of Si/resist and a temperature of the wafer may be disclosed. The etching selectivity may be improved at a temperature of no more than about −50° C. 
     When a merit of the etching at a low temperature may be caused by a coagulation of plasma, it may be advantageous to provide the wafer with the low temperature. In this case, risks such as a short, a damage, etc., may be generated by a dew condensation at a high voltage used in an electrostatic chuck (ESC). However, there may exist a limit for providing a gas with a low dew point. Because the gas having the low dew point and a dry air may be expensive, it may be required to invest a high cost. Further, the gas having the low dew point capable of responding a cooling at a temperature of no more than about −100° C. Thus, dew condensation may be frequently generated in the apparatus. 
     Further, technologies and apparatuses for cooling the wafer to the low temperature may be dawning. Thus, responses of the risks may be required on all such occasions. 
     The ESC may be used in the apparatus for supporting the wafer. The apparatus may include a high frequency power supply. Thus, when a short may be generated between a high voltage terminal and an RD plate by the ESC, functions of the ESC may be disappeared. The short may damage the apparatus. 
     When any action may not be taken on a low region of a cooled portion, an under structure of the apparatus may also have the low temperature so that the dew condensation may be generated at a portion contacted with an outside air. Further, because the apparatus may include a plurality of cables, an electric leakage may be generated. 
     In order to remove the risk by the dew condensation, a high temperature may be provided to a base plate contacted with the outside air to reduce or prevent the electric leakage. In order to reduce or prevent the dew condensation causing the short, an inner space of the apparatus may be isolated from an outside. A moisture amount in the apparatus may be minimally decreased. 
     Conventional art may disclose an apparatus for reducing or preventing a dew condensation. When plasma may be generated to heat an upper electrode of the apparatus, the upper electrode may be cooled. 
     However, it may not be sufficient to cool the wafer and perform a dry-etching process using the apparatus. Thus, when the dew condensation may be generated, a short may be generated between a high voltage terminal and an RF electrode. Further, when an air current or a moisture amount may not be considered, the dew condensation may also be generated by a local cooling of a gas. 
     SUMMARY 
     Example embodiments provide an apparatus for manufacturing a semiconductor device that may be capable of reducing or preventing a dew condensation. 
     According to example embodiments, there may be provided an apparatus for manufacturing a semiconductor device. The apparatus may include a vacuum chamber, an electrostatic chuck (ESC), a cooler, an RF plate, a casing, a base plate and a gas supplier. The ESC may be arranged in the vacuum chamber. The cooler may be configured to cool the ESC. The RF plate may be arranged under the cooler. The casing may be configured to support the cooler. The base plate may be opposite to the RF plate to form an inner space together with the casing. The gas supplier may supply a gas having a low dew point to the inner space. 
     According to example embodiments, the apparatus may reduce or prevent dew condensation and/or damage caused by a short. 
     In example embodiments, the casing may include at least two parts. O-rings may be interposed between the cooler and the casing, between the parts of the casing and between the casing and the base plate. 
     According to example embodiments, the inner space filled with the gas and a vacuum region may be sealed. 
     In example embodiments, the apparatus may further include an RF cable configured to supply a power for generating plasma in the vacuum chamber. O-rings may be interposed between the RF cable and the base plate and between the RF cable and the vacuum chamber. 
     According to example embodiments, the inner space filled with the gas and an outside air may be sealed. 
     In example embodiments, the gas supplier may include a gas-supplying member configured to supply the gas having the low dew point into the inner space with a constant pressure. 
     According to example embodiments, the inner space may be maintained under a positive pressure and the inner space may be filled with the gas having the low dew point. Thus, the outside air including moisture may not infiltrate into the vacuum chamber. 
     In example embodiments, the O-ring may include a very low temperature-corresponding seal member configured to cover both surfaces of a plasma-resistant seal material. The very low temperature-corresponding seal member may be received in a groove formed at the parts of the casing. The plasma-resistant seal material may be interposed between a gap between the parts of the casing. 
     According to example embodiments, wear of the O-ring caused by the plasma may be reduced or suppressed. Further, a sealing capacity may be secured at the very low temperature. 
     In example embodiments, the O-ring may include a flange formed at the plasma-resistant seal material. The flange may have a width wider than a width of a groove in the O-ring. 
     According to example embodiments, infiltration of the plasma into the groove of the groove may be reduced or prevented to reduce or prevent a damage of the very low temperature-corresponding seal member. 
     In example embodiments, the apparatus may further include a trap configured to trap moisture in the inner space. 
     According to example embodiments, the moisture in the inner space may be trapped to reduce or prevent dew condensation. 
     In example embodiments, the trap may function as to decrease a temperature of a gas in a gap between the RF plate and a block configured to providing a cooling fluid of the cooler to induce the moisture into the trap. 
     In example embodiments, the apparatus may further include a pipe connected to the block in the inner space. The pipe may be branched from a passage to induce the moisture into the trap. 
     According to example embodiments, the moisture in the inner space may be trapped to reduce or prevent dew condensation. Further, the moisture adjacent to the ESC or the RF plate may be sufficiently removed. 
     In example embodiments, the apparatus may further include an acoustic emission (AE) sensor arranged in the inner space of the casing. A friction, a wear, a crack and/or a fracture of the casing may be detected based on amplitude of a vibration and a shape of a vibration waveform detected by the AE sensor. 
     According to example embodiments, when the casing may be exposed to a high temperature, the casing may be damaged by a temperature difference between the casing and the RF plate. The AE sensor may previously detect the damage of the casing to reduce or prevent a damage of the apparatus. 
     According to example embodiments, the generation of the dew condensation at the very low temperature may be reduced or prevented. Thus, a damage caused by a short, which may be generated by the dew condensation, may also be reduced or prevented. Further, a damage of the O-ring caused by the plasma may be reduced or prevented to maintain the vacuum. Furthermore, a damage of the casing caused by the temperature difference may also be reduced or prevented. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Example embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.  FIGS. 1 to 12  represent non-limiting, example embodiments as described herein. 
         FIG. 1  is a cross-sectional view illustrating an apparatus for manufacturing a semiconductor device in accordance with example embodiments; 
         FIG. 2  is a contour diagram illustrating a temperature distribution when a gas circulates in an inner space by a pump; 
         FIG. 3  is a contour diagram illustrating a temperature distribution of a gap between an inner surface of an RF plate and a block of a casing; 
         FIG. 4  is a contour diagram illustrating a temperature distribution of a gap between an outer surface of an RF plate and a block of a casing; 
         FIG. 5  is a contour diagram illustrating a temperature distribution when a gas not circulates in an inner space by a pump; 
         FIG. 6  is a contour diagram illustrating a temperature distribution of the gap between the inner surface of the RF plate and the block of the casing in  FIG. 5 ; 
         FIG. 7  is a contour diagram illustrating a temperature distribution of the gap between the outer surface of the RF plate and the block of the casing in  FIG. 5 ; 
         FIG. 8  is a cross-sectional view illustrating an O-ring of a semiconductor fabrication apparatus in accordance with example embodiments; 
         FIG. 9  is a cross-sectional view illustrating an apparatus for manufacturing a semiconductor device in accordance with example embodiments; 
         FIG. 10  is a cross-sectional view illustrating an apparatus for manufacturing a semiconductor device in accordance with example embodiments; 
         FIG. 11  is a graph showing an AE wave form in a friction and wear condition; and 
         FIG. 12  is a graph showing an AE waveform in a crack and fracture condition. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Hereinafter, example embodiments will be explained in detail with reference to the accompanying drawings. 
       FIG. 1  is a cross-sectional view illustrating an apparatus for manufacturing a semiconductor device in accordance with example embodiments. 
     Referring to  FIG. 1 , an apparatus  100  for manufacturing a semiconductor device may include a vacuum chamber  101 , an electrostatic chuck (ESC)  102 , a cooler  103 , a base plate  105 , a casing  106 , a gas supplier  107 , an O-ring  108 , a reaction gas supplier  109  and/or a focus ring  110 . 
     Plasma may be generated in a vacuum space  160  over the ESC  102 . The apparatus  100  may include an upper electrode. The casing  106  may include at least one part. 
     The vacuum chamber  101  may be configured to receive the ESC  102 , the cooler  103 , the base plate  105  and the casing  106 . The vacuum chamber  101  may have a vacuum space  160 . A heater  113  may heat the vacuum chamber  101 . An exhaust apparatus  112  may be configured to provide the vacuum space  160  with vacuum. The exhaust apparatus  112  may include a vacuum pump connected to the vacuum space  160 . 
     The ESC  102  may be configured to fix a substrate  10 . The ESC  102  may be arranged in the vacuum chamber  101 . A DC power  121  and an HV terminal  122  may be connected to the ESC  102 . The DC power may supply a high voltage for fixing the substrate to the ESC  102 . The ESC  102  may be positioned on the cooler  103  using an adhesive. The ESC  102  may include an optical fiber thermometer  123 . 
     The cooler  103  may be configured to cool the ESC  102 . The cooler  103  may include a cooling plate  131  and a chiller  132 . The cooling plate  131  may include a cooling passage  133  through which a cooling fluid may circulate. The chiller  131  may generate the cooling fluid circulating the cooling passage  133 . 
     An RF plate  141  may be opposite to the upper electrode. Thus, the RF plate  141  may function as a lower electrode. The RF plate  141  may be electrically connected with an alternate current power supply  142  through an RF cable  142 . The RF power supply  142  may generate a high frequency for generating the plasma. The RF cable  142  may supply the power to the vacuum space  160 . The plasma may be generated in the vacuum space  160  over the substrate  10  by supplying the power from through the RF cable  142 . 
     The base plate  105  may be opposite to the RF plate  141 . The base plate  105  may form an inner space  161  together with the casing  106 . The base plate  105  and a block  111  of the casing  106  may be configured to seal a region under the cooling plate  131 . 
     The casing  106  may be configured to support the RF plate  141  for supporting the cooler  103 . The casing  106  may make contact with the cooler  103  and the base plate  105  to form the inner space  161 . In order to isolate the RF plate  141  and the base plate  105  from each other, the casing  106  may include ceramic. 
     The gas supplier  107  may include a gas-supplying member  171 . The gas supplier  107  may further include a thermometer  172  and a pump  173 . The gas-supplying member  171  may supply a gas having a low dew point to the inner space  161  to provide the inner space  161  with a positive pressure. The thermometer  172  may measure a dew point of the inner space  161 . The pump  173  may circulate the gas between the inner space  116  and the thermometer  172 . The gas-supplying member  171  may control a pressure of the inner space  161 . When the pressure of the inner space  161  may be no more than a predetermined or alternatively, desired value, the gas-supplying member  171  may automatically supply the gas into the inner space  161 . Further, when a leakage may be generated, the gas-supplying member  171  may constantly supply the gas to continuously provide the inner space  161  with the positive pressure. 
     The reaction gas supplier  109  may be configured to supply a reaction gas between the substrate  10  and the ESC  102 . The reaction gas supplier  109  may include a nozzle  191  and a controller  192 . The nozzle  191  may be electrically connected to the controller  192 . The nozzle  191  may inject the reaction gas to the ESC  102 . The controller  192  may supply the reaction gas to the nozzle  191 . 
     Hereinafter, simulation results of the cooling by the apparatus  100  may be illustrated in detail. 
       FIGS. 2 to 4  show temperature distributions when the pump  183  in the inner space  161  is operated.  FIG. 2  is a contour diagram illustrating a temperature distribution of the gas passing through the block  111  in the inner space  161 . In  FIG. 2 , temperatures are shown by light and shade of a color. Referring to  FIG. 2 , “−6.522528E-03” may indicate “−6.522528×10 −3 ”. 
       FIG. 3  is a contour diagram illustrating a temperature distribution of a gap between an inner surface of the RF plate and the block of the casing. In  FIG. 3 , temperatures are shown by light and shade of a color. Further, a left may be oriented toward a central portion and a right may be oriented toward the block  111 .  FIG. 4  is a contour diagram illustrating a temperature distribution of a gap between an outer surface of the RF plate and the block of the casing. In  FIG. 4 , temperatures are shown by light and shade of a color. Further, a left may be oriented toward the block  111  and a right may be oriented toward the casing  106 . 
       FIGS. 5 to 7  show temperature distributions when the pump  183  in the inner space  161  is not operated.  FIG. 5  is a contour diagram illustrating a temperature distribution of the gas passing through the block  111  in the inner space  161 . In  FIG. 5 , temperatures are shown by light and shade of a color.  FIG. 6  is a contour diagram illustrating a temperature distribution of the gap between the inner surface of the RF plate and the block of the casing in  FIG. 5 . In  FIG. 6 , temperatures are shown by light and shade of a color. Further, a left may be oriented toward a central portion and a right may be oriented toward the block  111 .  FIG. 7  is a contour diagram illustrating a temperature distribution of the gap between the outer surface of the RF plate and the block of the casing in  FIG. 5 . In  FIG. 7 , temperatures are shown by light and shade of a color. Further, a left may be oriented toward the block  111  and a right may be oriented toward the casing  106 . 
     Referring to  FIGS. 2 to 4 , it can be noted that when the gas may forcibly circulate in the inner space  161  by the pump  183 , a temperature of the gas at a high voltage portion in the inner space  161  may not be decreased. Further, it can be noted that the gas flowing through the labyrinth structure between the RF plate  141  and the block  111  may have a minimum temperature to function as a trap for inducing the dew concentration. 
     In contrast, referring to  FIGS. 5 to 7 , it can be noted that a temperature of the gas at a high voltage portion in the inner space  161  may not be decreased although a natural convection. Further, it can be noted that the gas flowing through the labyrinth structure between the RF plate  141  and the block  111  may have a minimum temperature to function as a trap for inducing the dew concentration. 
     The apparatus  100  may be applied to a dry etching apparatus using the plasma. When the apparatus  100  may include the dry etching apparatus, the wafer on the ESC  102  may be maintained at a very low temperature. The cooler  103  may be positioned adjacent to the ESC  102 . That is, in order to maintain the very low temperature, the cooling plate  131  may be positioned beneath the ESC  102 . The cooling fluid may circulate through the cooling passage  133  to cool the heat. 
     Further, in order to reduce an expansion of the cooling passage  133  in the inner space  161 , the casing  106  may include ceramic. The block  111  may be connected with the cooling plate  131  through the O-ring  108 . 
     Furthermore, a pipe may be connected to the block  111  to previously remove the moisture. 
     The ESC  102  may be coupled to the HV terminal  122 . The RF plate  141  may be arranged under the cooling plate  131 . The cooling plate  131  may be coupled to the alternate current power supply  142  through the RF cable  142 . In order to isolate the inner space  161  from the outside air, the base plate  105  may be positioned under the RF plate  141 . Outer connections may be sealed. 
     When the block  111  may make contact with the RF plate  141  or the cooling plate  131 , the RF plate  141  may be cooled to accelerate the dew concentration of the RF plate  141 . Thus, the O-ring  108  may be interposed between the block  111  and the RF plate  141  and between the block  111  and the cooling plate  131 . Because a temperature of the O-ring  108  may be decreased to a temperature of the block  111 , the O-ring  108  may include a material usable at the temperature of the block  111 . 
     In order to reduce or prevent the dew concentration between the base plate  105  and the outside, a heater may be installed under the base plate  105  to maintain the high temperature of the base plate  105 . Alternatively, a heating element  113  in the vacuum chamber  101  may heat the base plate  105 . Thus, the dew concentration of the base plate  105  may be reduced or prevented by maintaining the high temperature of the base plate  105 . As a result, an electric leakage caused by a water drop on a cable under the base plate  105  may also be reduced or prevented. 
     When the dew concentration may be generated in the inner space  161 , a pump  173  may circulate a fluid to reduce or prevent temperatures of portions in the inner space  161  from being decreased under a dew point. Further, in order to reduce or prevent a direct contact between the fluid from the pump  173  and the RF plate  141 , a diffusion plate may be arranged at an inlet to assist the flow in the inner space  161 . The pump  173  may provide the fluid to improve a measurement accuracy of the thermometer  172 . 
     Further, before a low temperature process, the inner space  161  may be purged by the gas having the low dew point from the gas-supplying member  171 . The inner space  161  may be maintained at the positive pressure. That is, because the temperature of the inner space  161  may be decreased under the low temperature process to drop the pressure of the inner space  161 , the pressure of the inner space  161  may be controlled to provide the inner space  161  with the positive pressure. 
     According to example embodiments, the inner space  161  may be filled with the gas having the low dew point and the inner space  161  may have the positive pressure. Thus, the outside air may not infiltrate into the apparatus. The trap may remove the tiny moisture in the inner space  161  to reduce or prevent the dew concentration. 
       FIG. 8  is a cross-sectional view illustrating an O-ring of a semiconductor fabrication apparatus in accordance with example embodiments. 
     Referring to  FIG. 8 , the O-ring  108  may include an O-ring  801 , an O-ring  802  and/or an O-ring  803 . The O-ring  801  may include a plasma-resistant material. Further, the O-ring  801  may include a wear-resistant material so that particles including a metal may not be generated from the O-ring  803 . 
     The O-ring  802  and the O-ring  803  may include a material having elasticity for maintaining the vacuum at a temperature of about −110° C. 
     The O-ring  801  may be positioned between the O-ring  802  and the O-ring  803 . 
     In order to attach the O-rings  801  to the casing  106 , a dovetail groove may be formed at the two parts of the casing  106 . 
     Generally, a low temperature-resistant material may have a low radical-resistant property and high plasma consumption. When the O-rings  801 ,  802  and  803  may be exposed to the very low temperature, although the O-ring  801  may be inwardly contracted, the O-ring  802  may be expanded by the contraction of the O-ring  801 , because the O-ring  802  may have the very low temperature-resistant property, to have the sealing capacity. 
     Further, the O-ring  801  may include a flange  811 . The flange  811  may have a width wider than a width of the O-ring  801 . When the O-ring  801  may be exposed to the plasma, the flange  811  may block the infiltration of the plasma into the O-ring  802  to reduce or prevent the O-ring  802  from being exposed to the plasma. 
     According to example embodiments, the plasma-resistant seal material may be arranged at a position from the gap to which the plasma may reach. The very low temperature-corresponding seal member may cover the plasma-resistant material at a position from the gap to which the plasma may not reach. Thus, the wear of the O-ring caused by the plasma may be suppressed to secure the sealing capacity at the very low temperature. 
       FIG. 9  is a cross-sectional view illustrating an apparatus for manufacturing a semiconductor device in accordance with example embodiments. In  FIG. 9 , the same reference numerals may refer to the same elements and any further illustrations with respect to the same elements may be omitted herein for brevity. 
     Referring to  FIG. 9 , an apparatus  900  for manufacturing a semiconductor device may include a vacuum chamber  101 , an ESC  102 , a cooler  103 , a base plate  105 , a casing  106 , a gas supplier  107 , an O-ring  108 , a reaction gas supplier  109 , a focus ring  110  and/or a trap  901 . 
     Plasma may be generated in a vacuum space  160  over the ESC  102 . The apparatus  900  may include an upper electrode. The casing  106  may include at least one part. 
     The trap  901  may be configured to trap tiny moisture in the inner space  161 . The trap  901  may be connected to the cooling passage  133  from the cooler  103  through a pipe. The trap  901  may function as to trap the moisture on a surface exposed to the inner space  161  at a minimum temperature. 
     According to example embodiments, the trap may trap the moisture in the inner space to reduce the moisture in the inner space. The temperature of the gas in the gap between the RF plate  141  and the block  111  may be decreased to trap the moisture, which may be caused by the dew concentration, in the trap  901 . Further, the pipe branched from the cooling passage  133  may be connected to the block  111  to trap the moisture in the trap  901 . 
       FIG. 10  is a cross-sectional view illustrating an apparatus for manufacturing a semiconductor device in accordance with example embodiments. In  FIG. 10 , the same reference numerals may refer to the same elements and any further illustrations with respect to the same elements may be omitted herein for brevity. 
     Referring to  FIG. 10 , an apparatus  1000  for manufacturing a semiconductor device may include a vacuum chamber  101 , an ESC  102 , a cooler  103 , a base plate  105 , a casing  106 , a gas supplier  107 , an O-ring  108 , a reaction gas supplier  109 , a focus ring  110 , an AE sensor  1001  and/or an AE sensor circuit  1002 . 
     Plasma may be generated in a vacuum space  160  over the ESC  102 . The apparatus  1000  may include an upper electrode. The casing  106  may include at least one part. 
     The AE sensor  1001  may convert amplitude of a vibration of the casing into an electrical signal. The AE sensor  1001  may then output the electrical signal to the AE sensor circuit  1002 . 
     The AE sensor circuit  1002  may detect an electrical signal generated by a friction and a wear between the two pars of the casing  106  from the amplitude detected by the AE sensor  1001 . Further, the AE sensor circuit  1002  may detect an electrical signal for predicting a fracture of the casing  106 . 
       FIG. 11  is a graph showing an AE waveform in a friction and wear condition, and  FIG. 12  is a graph showing an AE waveform in a crack and fracture condition. In  FIGS. 11 and 12 , a horizontal axis may represent a time and a vertical axis may represent amplitude. 
     When the AE sensor circuit  1002  may detect an AE waveform in  FIG. 11  or  FIG. 12 , the AE sensor circuit  1002  may output the detected results. A friction, a wear, a crack and/or a fracture of the casing  106  may be detected based on amplitude of a vibration and a shape of a vibration waveform detected by the AE sensor  1001 . 
     According to example embodiments, when the casing may be exposed to a high temperature, the casing may be damaged by a temperature difference between the casing and the RF plate. The AE sensor may previously detect the damage of the casing to reduce or prevent a damage of the apparatus. Further, a controller may analyze the shape of the AE waveform. The controller may notice the phenomenon in the vacuum chamber  101  such as an alarm. 
     The present inventive concepts may not be restricted within the above-mentioned example embodiments. For example, the above-mentioned example embodiments may be variously combined with each other. 
     Further, the temperature of the example embodiments may be a temperature for generating the dew concentration with respect to a room air. For example, because the gas having the low dew point may not be easily secured, the functions of the example embodiments may be exhibited at a temperature of no more than about −60° C. However, because the seal member may have a restricted cold resistance, the functions of the example embodiments may not be exhibited at a temperature of −110° C. 
     One or more of the elements disclosed above may include or be implemented in one or more processing circuitries such as hardware including logic circuits; a hardware/software combination such as a processor executing software; or a combination thereof. For example, the processing circuitries more specifically may include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, application-specific integrated circuit (ASIC), etc. 
     The foregoing is illustrative of example embodiments and is not to be construed as limiting thereof. Although example embodiments have been described, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from the novel teachings and/or advantages of the present inventive concepts. Accordingly, all such modifications are intended to be included within the scope of the present inventive concepts as defined in the claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Therefore, it is to be understood that the foregoing is illustrative of various example embodiments and is not to be construed as limited to the specific example embodiments disclosed, and that modifications to the disclosed example embodiments, as well as other example embodiments, are intended to be included within the scope of the appended claims.