Abstract:
A temperature control apparatus of a gas pipe heating jacket prevents a heat transfer through a pipe having unreactive residual gas and maintains the temperature of the gas in the event that a first hot wire in the heating jacket is damaged or otherwise inoperable through the use of a second hot wire. By maintaining the temperature of the gas flowing through the pipe, crystallization due to heat differences is avoided thereby preventing pipe blockage and subsequent process errors. The temperature control apparatus includes a controller, a power supply controller, first and second hot wires, a relay, a temperature sensor and a display. The first and second hot wires heat the gas pipe with AC power supplied from power supply controller. The relay selectively supplies the AC power to the first or second hot wire in response to the relay switching signal from the controller. The temperature sensor senses a heating temperature of the gas pipe. A display individually indicates drive states of the first and second hot wires in response to the control signal from the controller.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to gas pipe heating jackets, and more particularly, to a temperature control apparatus of a gas pipe heating jacket, which is capable of preventing a heat transfer through a pipe, in a gas pipe having unreactive residual gas, and of constantly maintaining temperature of the gas. 
         [0003]    This application claims priority under 35 U.S.C. §119 from Korean Patent Application 10-2006-0052415, filed on Jun. 12, 2006, the entire contents of which are hereby incorporated by reference. 
         [0004]    2. Discussion of Related Art 
         [0005]    In general, semiconductor devices are manufactured using many fabrication steps or processes. Many of these processes use various types of gases in a high-vacuum state. Typically, a process chamber is coupled to a vacuum device through an exhaust pipe in order to form a vacuum state of a reaction chamber in which the processes are performed on a semiconductor substrate. The vacuum device controls a pressure of the process chamber and is used to discharge reactive gas remaining within the chamber, reactive by-products and unreactive gases generated during the particular process. 
         [0006]    A gas pipe is used to discharge the unreactive gas and reactive by-products from the chamber. This gas pipe may be blocked due to a temperature difference between the interior and exterior of the chamber. Because of this temperature difference, the unreactive gas and reactive by-products may crystallize into a solid state, such as a powder, at a low temperature. The solid crystals may adhere to the interior of the gas pipe and block gases from being discharged from the chamber during manufacturing. 
         [0007]      FIG. 1  illustrates a temperature control apparatus of a conventional gas pipe that includes a rectifying unit  10  for receiving an AC power source which drops a voltage and outputs a DC power source. A microprocessor unit (MPU)  12  receives DC power supplied from rectifying unit  12  and outputs a control signal to heat a hot wire  20  to a predetermined temperature in response to a digital temperature sense signal. A power supply controller  14  constructed of an SSR (Solid State Relay), supplies or cuts-off the AC power in response to the control signal from MPU  12 . Hot wire  20  surrounds and heats gas pipe  16  using AC power supplied from power supply controller  14 . A temperature sensor  22  senses the temperature of hot wire  20  and A/D converter  24  converts the temperature sensed by temperature sensor  22  into a digital signal and provides it to MPU  12 . A temperature display  26  indicates a temperature value in response to the control signal from MPU  12 . Heating jacket  18  may be configured to include hot wire  20  and temperature sensor  22 . 
         [0008]      FIG. 2A  illustrates an assembled heating jacket  18  and  FIG. 2B  illustrates a disassembled heating jacket  18  shown in  FIG. 1 . The heating jacket  18  includes a first insulation layer  30  that surrounds gas pipe  16  and provides electrical insulation between gas pipe  16  and the hot wire. A second insulation layer  32  surrounds hot wire  20  and provides electrical insulation therefore. A fixation layer  34  surrounds second insulation layer  32  and prevents displacement of this insulation layer. First insulation layer  30  surrounds the girth of gas pipe  16 . Hot wire  20  is wound around first insulation layer  30  and second insulation layer  32  surrounds hot wire  20 . In this heating jacket  18  configuration, the temperature of the gas flowing in gas pipe  16  is heated to a predetermined temperature by hot wire  20 . In particular, power is supplied and a voltage is dropped and rectified in rectifying unit  10 . This DC voltage is applied to MPU  12  and temperature display  26 . The MPU  12  turns on power supply controller  14  to supply AC power to hot wire  20  which heats gas pipe  16 . The gas flowing in pipe  16  is in turn heated such that the gas does not adhere in a solid state to gas pipe  16 . 
         [0009]    A temperature sensor  22  senses the temperature of gas pipe  16  and applies the sensed temperature to A/D converter  24  which converts the sensed temperature into a digital signal and supplies it to MPU  12 . MPU  12  compares the sensed digital temperature with a predetermined temperature. If the sensed temperature is lower than the predetermined temperature, power supply controller  14  is turned on to supply AC power to hot wire  20  to heat gas pipe  16 . If the sensed temperature is higher than the predetermined temperature, power supply controller  14  cuts-off AC power supplied to hot wire  20 . 
         [0010]    A drawback associated with such a temperature control apparatus is that if hot wire  20  is damaged or otherwise not functioning properly, the temperature of heating jacket  18  may become lower than the predetermined temperature. The gas flowing through the pipe cools and changes to a solid crystalline state, such as powder, and adheres to the interior of gas pipe  16  thereby blocking gas flow and causing process errors. 
       SUMMARY OF THE INVENTION 
       [0011]    Exemplary embodiments of the present invention are directed to a temperature control apparatus of a gas pipe heating jacket to control the temperature of gas flowing in a pipe during a semiconductor manufacturing process where the heating jacket includes first and second hot wires. The apparatus includes a temperature sensor configured to sense the temperature of the first and second hot wires and a controller. The controller receives the sensed temperature signal and outputs a control signal to heat the first or second hot wires to a predetermined temperature in response to the sensed temperature signal. The controller further outputs a relay switching signal to heat the first or second hot wires when the sensed temperature does not reach an associated predetermined temperature within a predetermined time period. A display is also utilized to indicate drive states of the first and second hot wires in response to the control signal. In this manner, if the first hot wire is damaged or is otherwise inoperable, a second hot wire heats the gas pipe thereby avoiding solids from forming within the pipe. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  illustrates the configuration of temperature control apparatus of a conventional gas pipe; 
           [0013]      FIG. 2A  illustrates an assembled state of heating jacket shown in  FIG. 1 ; 
           [0014]      FIG. 2B  illustrates a disassembled state of the heating jacket shown in  FIG. 1 ; 
           [0015]      FIG. 3  illustrates the configuration of a temperature control apparatus of a gas pipe according to an embodiment of the invention; 
           [0016]      FIG. 4A  illustrates an assembled state of heating jacket shown in  FIG. 3 ; 
           [0017]      FIG. 4B  illustrates a disassembled state of the heating jacket shown in  FIG. 3 ; 
           [0018]      FIG. 5  is a flowchart of a process to switch from one hot wire to another hot wire in accordance with an embodiment of the invention; 
           [0019]      FIG. 6  illustrates the configuration of a temperature control apparatus of a gas pipe according to an embodiment of the invention; and 
           [0020]      FIG. 7  is a flowchart of a process to switch to a hot wire when another hot wire is damaged, according to an embodiment of the invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0021]    The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention, however, may be embodied in many different forms and should not be construed 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 invention to those skilled in the art. In the drawings, like numbers refer to like elements throughout. 
         [0022]      FIG. 3  illustrates a temperature control apparatus in combination with gas pipe  56  including a heater control board  64  and a heating jacket  62  having first and second hot wires  50  and  52 . Heater control board  64  includes a rectifying unit  40 , an MPU  42 , a power supply controller  46 , A/D converter  44  and relay  48 . Rectifying unit  40  receives AC power, drops a voltage, rectifies it and outputs DC power to MPU  42 . MPU  42  outputs a control signal to heat heating jacket  62  to a predetermined temperature in response to a digital temperature sense signal. MPU  42  also outputs a relay switching signal when the temperature of heating jacket  62  does not reach a predetermined temperature within a predetermined time period. 
         [0023]    Power supply controller  46 , constructed of an SSR(Solid State Relay), supplies or cuts-off the supply of AC power to hot wires  50  and  52  in response to the control signal from MPU  42 . Relay  48  selectively supplies AC power provided by power supply controller  46  to first or second hot wires  50 ,  52  in response to a relay switching signal from MPU  42 . Temperature sensor  54  senses the temperature of first and second hot wires  50  and  52 . A/D converter  44  converts the temperature sensed by temperature sensor  54  into a digital signal and provides it to MPU  42 . Heater control board  64  also includes first and second LEDs  58  and  60  which indicate a drive state of the first and second hot wires  50  and  52  in response to the control signal from MPU  42 . First hot wire  50  and temperature sensor  54  may be included in heating jacket  62 . 
         [0024]      FIG. 4A  illustrates an assembled state of heating jacket  62  and  FIG. 4B  illustrates heating jacket  62  in a disassembled state. A first insulation layer  70  surrounds gas pipe  56  and provides electrical insulation between gas pipe  56  and first and second hot wires  50  and  52 . First and second hot wires  50  and  52  heat gas pipe  56  and are wound around first insulation layer  70 . Second insulation layer  72  surrounds first and second hot wires  50  and  52  to provide electrical insulation therefore. Fixation layer  74  surrounds and securely retains the second insulation layer  72  in place. 
         [0025]    In operation, power is supplied by the AC unit and a voltage is dropped and rectified in rectifying unit  40  thereby providing a DC voltage to MPU  42 . MPU  42  turns on power supply controller  46  and supplies AC power to relay  48  which selects first hot wire  50  in response to the relay switching signal from MPU  42 . Power supply controller  46  supplies AC power to first hot wire  50  which heats gas pipe  56 . When first hot wire  50  reaches a predetermined temperature within a predetermined time, MPU  42  lights up first LED  60  with a particular color, such as green. When hot wire  50  is not at the predetermined temperature, MPU  42  lights up the first LED  60  with a different color, for example red. When gas pipe  56  is heated, gas flowing in gas pipe  56  is likewise heated preventing gas from crystallizing and adhering to pipe  56 . When gas pipe  56  is heated by first hot wire  50 , temperature sensor  54  senses the temperature of the first and second hot wires  50  and  52  and supplies the temperature reading to A/D converter  44 . A/D converter  44  converts the sensed temperature into a digital signal and applies it to MPU  42  which compares this digital temperature with a predetermined temperature. If the measured temperature is lower than the predetermined temperature, power supply controller  46  is turned on to supply AC power to first hot wire  50  so as to heat gas pipe  56 . If the measured temperature is higher than the predetermined temperature, power supply controller  46  turns off AC power to first hot wire  50 . In the event that the temperature sensed by temperature sensor  54  does not reach the predetermined temperature within a predetermined time, MPU  42  determines that first hot wire  50  is damaged and provides a relay switching signal to relay  48 . Relay  48  receives this relay switching signal from MPU  42  and supplies AC power to second hot wire  52  via power supply controller  46 . In this manner, the temperature of gas pipe  56  is controlled by second hot wire  52 . MPU  42  lights up second LED  60  to indicate a temperature control state of gas pipe  56  through second hot wire  52 . That is, when second hot wire  52  reaches a predetermined temperature within a predetermined time, second LED  62  lights up with a color, for example green, to indicate a normal state. If the predetermined temperature is not reached, second LED  62  lights up with a different color, such as red, to indicate a failed state. 
         [0026]      FIG. 5  is a flowchart illustrating a method of switching from first hot wire  50  to second hot wire  52  by MPU  42  when the first hot wire is damaged or otherwise not operating properly. In step  101 , MPU  42  resets first hot wire  50  to an active state and is verified at step  102 . In step  103 , MPU  42  outputs a first switching signal to supply AC power through power supply controller  46  to first hot wire  50  so as to heat the first hot wire  50 . In step  104 , MPU  42  checks whether or not temperature of the first hot wire  50  sensed by temperature sensor  54  and received through A/D converter  44  reaches a predetermined temperature within a predetermined time. If the predetermined temperature is reached, MPU  42  turns on first LED  58  to indicate a drive state of first hot wire  50  at step  105 . If first hot wire  50  does not reach the predetermined temperature within the predetermined time, hot wire  50  is in a fail state and second hot wire  52  is set to an active state at step  113 . Also at step  113 , a switching signal selects second hot wire  52  and relay  48  supplies AC power through power supply controller  46  to second hot wire  52  to heat the second hot wire. 
         [0027]    At step  102 , a determination is made whether or not first hot wire  50  is in an active state. If first hot wire is not in an active state, MPU  42  outputs second switching signal to apply AC power through power supply controller  46  to second hot wire  52  so as to heat the second hot wire  52  at step  106 . In step  107 , MPU  42  checks whether or not the temperature of second hot wire  52  sensed by temperature sensor  54  and received through A/D converter  44  reaches a predetermined temperature within a predetermined time. If second hot wire  52  reaches a predetermined temperature within a predetermined time, MPU  42  turns on the second LED  60  in the step  108  to indicate a drive state of second hot wire  52 . If second hot wire  52  does not reach the predetermined temperature within a predetermined time, hot wire  52  is in a fail state and first hot wire  52  is set to an active state at step  109  and outputs a switching signal to select first hot wire  50 . A determination is made at step  110  whether the first and second hot wires  50  and  52  are in a fail state. If the hot wires are in a fail state, MPU  42  turns on first and second LEDs  58  and  60  with a particular color, for example red, at step  111 . If one of the first and second hot wires  50  and  52  are not in a fail state, at step  112  MPU  42  lights up the LED not indicating the fail state with a particular color, for example, green and the LED indicating the fail state with a particular color, for example green, and the process returns to step  102 . For example, if first hot wire  50  is in a fail state, first LED  58  lights up with the color red and second LED  60  lights up with green. 
         [0028]      FIG. 6  illustrates rectifying unit  40  which receives AC power, drops a voltage, rectifies it and outputs DC power. MPU  42  receives DC power source supplied from rectifying unit  40  and outputs a control signal to heat first and second hot wires  50  and  52  to a predetermined temperature in response to a sensed temperature value. If the sensed temperature does not reach a predetermined temperature within a predetermined time period, MPU  42  outputs a relay switching signal and outputs a control signal to indicate a normal or fail state of first and second hot wires  50  and  52 . Power supply controller  46  provides or cuts-off AC power in response to the control signal from MPU  42 . First and second hot wires  50  and  52  surround gas pipe  56  and are heated by AC power supplied from power supply controller  46 . Relay  48  selectively supplies power from power supply controller  46  to first or second hot wire  50  or  52  in response to relay switching signal from MPU  42 . Temperature sensor  54  senses the temperature of first and second hot wires  50  and  52 . A/D converter  44  converts the sensed temperature by temperature sensor  54  into a digital signal and provides it to MPU  42 . A display  66  indicates the temperature and a normal or fail state of first and second hot wires  50  and  52 . Display  66  also provides an active or standby state of first and second hot wires  50  and  52  in response to a control signal from MPU  42 . Rectifying unit  40 , MPU  42 , A/D converter  44 , power supply controller  46  and relay  48  may be included in heater control board  64 . Power supply controller  46  may be constructed of a solid state relay (SSR). 
         [0029]      FIG. 7  is a flowchart illustrating a control flow of MPU  42  to switch from one hot wire to another when a hot wire is damaged or otherwise not functioning properly. In step  201 , MPU  42  resets first hot wire  50  to an active state and MPU  42  checks whether first hot wire  50  is in an active state at step  202 . If first hot wire  50  is in an active state, MPU  42  outputs a first switching signal to enable relay  48  to provide AC power to first hot wire  50  via power supply controller  46  at step  203 . In step  204 , MPU  42  checks whether or not the temperature of first hot wire  50 , sensed by temperature sensor  54  and received through A/D converter  44 , reaches a predetermined temperature within a predetermined time. If first hot wire  50  reaches the predetermined temperature, MPU  42  indicates that first hot wire  50  is in a normal state via an exemplary message, for example “Normal” or “Active”. If the temperature of first hot wire  50  does not reach the predetermined temperature within the predetermined time, step  206  decides that first hot wire  50  is in a fail state and sets second hot wire  52  to an active state. 
         [0030]    If first hot wire  50  is not in an active state as determined at step  202 , MPU  42  outputs second switching signal to relay  48  to supply AC power to second hot wire  52  via power supply controller  46  to heat second hot wire  52  in step  206 . In step  207 , MPU  42  checks whether or not the temperature of second hot wire  52 , sensed by temperature sensor  54  and received through A/D converter  44 , reaches a predetermined temperature within a predetermined time. Display  66  indicates that second hot wire  52  is in a normal state via display of a character or text message, for example, “Normal, Active” at step  208 . When second hot wire  52  does not reach the predetermined temperature within a predetermined time, second hot wire  52  is in a failed state and first hot wire  50  is set to an active state at step  209 . In step  210 , MPU  42  checks whether both first and second hot wires  50  and  52  are in a fail state. If both first and second hot wires  50  and  52  are in a fail state, display  66  indicates this condition and returns to step  202 . If one of the first or second hot wires  50  or  52  is not in a fail state, step  212  is performed in which MPU  42  indicates a normal state for the hot wire not in a fail state and indicates a fail state for the hot wire not in the normal state and returns to step  202 . For example, if first hot wire  50  is in a fail state, display  66  indicates such condition by displaying, for example “Normal, Active”. If second hot wire  52  is in a fail state, display  66  indicates such condition by displaying, for example “Fail, Standby”. 
         [0031]    In this manner, a temperature control apparatus utilizes first and second hot wires to heat a gas pipe during semiconductor manufacturing. When one hot wire having an active state does not reach a predetermined temperature within a predetermined time, the apparatus switches to the other hot wire which is in a standby state to heat the gas pipe. By providing a plurality of hot wires to heat the gas pipe, crystallization of gas within the pipe is avoided thereby preventing pipe blockage which may produce semiconductor process errors. 
         [0032]    Although the present invention has been described in connection with the embodiment of the present invention illustrated in the accompanying drawings, it is not limited thereto. It will be apparent to those skilled in the art that various substitutions, modifications and changes may be thereto without departing from the scope and spirit of the invention.