Abstract:
The present invention provides an injector robot for replacing a gas injector in a running furnace, which is still running and without any cooling and reheating action. According to the present invention, the injector robot is arranged and mounted upon a boat elevator, which is originally used to transport a boat with wafers into the furnace. The replacement of the gas injector could be executed precisely and safely by the assistant means and will not affect the predetermined procedure of the furnace.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a mechanistic apparatus used for replacing a tubular means, and more particularly relates to an injector robot used for replacing a gas injector in a furnace. 
     2. Description of the Prior Art 
     FIG. 1 illustrates a schematic structure of a vertical furnace  100 . The vertical furnace  100  is equipped with a thermal insulating cover  102  within. Within the internal area of the thermal insulating cover  102 , an outer quartz tube  104 , an inner quartz tube  106  and a plurality of heaters  108  are arranged to form a process tube  110  with a cylindrical space. Various reaction gases used in the process tube  110  are introduced by gas supply conduits  112  and gas injectors  116  and are finally discharged by gas exhaust conduits  114 . The gas injector  116  is used to conduct the reaction gas and release it at the designate position in the process tube  110 . Plurality of semiconductor substrates such as silicon wafer is housed in a quartz-made boat  120 , which is mounted on a platform  118  of a boat elevator  120 . Hence, during a thermal oxidation process, wafers carried by the boat  120  will be moved upward into the process tube  110  and finally moved downward from the process tube  110  by the supporting of the boat elevator  120  in the vertical furnace  100 . 
     After a certain amount of thermal chemical processing deposition, the gas injector  116  must be dropped from the vertical furnace  100  and replaced by a new one. In a conventional gas injector replacing process, the temperature within the process tube  110  must be cooled down to about 400-500° C., then an operator that wearing heat-insulating gloves can pull out the gas injector  116  from the gas supply conduit  114 . Afterward, to the contrary of the above-described operation, a new gas injector  116  with same or different specification is provided and inserted into the gas supply conduit  114 , then the process tube  110  will be heated up to the normal operating temperature (ex. usually about 600° C.). But during the replacing process, an unexpected-breaking gas injector  116  will probably scald the furnace operator standing below the process tube  110 . Alternatively, another method for replacing the gas injector is adopted to stop the operation of the vertical furnace  100  until the temperature, within the process tube  110 , is cooled to room temperature for lowering the danger to the furnace operator. But it will take about 4-5 hours for the cooling and reheating steps and delay the predetermined program of the vertical furnace  100 . 
     In the two above conventional gas injector replacing processes, frequently cooling and reheating processes executed in the vertical furnace  100  will chap the reactive film coated on the wall of the process tube  110 , thus particle pollution will occur in the vertical furnace  100 . Besides, the above manual operations for replacing the gas injectors  116  are difficult to control because the length of the gas injectors  116  always exceed over 1 meter, and the furnace operator can not guarantee that he/she could insert the gas injector  116  into the gas supply conduit  112  with a parallel and unsloping angle. 
     Therefore, a mechanistic assistant apparatus is proved necessary for the operator to replace the gas injector  116  in the vertical furnace  100 , which is still running and without any cooling and reheating action. Then the replacement of the gas injector  116  could be executed precisely and safely by the assistant means and will not affect the predetermined procedure of the vertical furnace  100 . 
     SUMMARY OF THE INVENTION 
     As above descriptions, one object of the present invention is providing an injector robot for replacing a gas injector in a furnace precisely and safely and will not delay the predetermined procedure of the furnace. 
     Another object of the present invention is providing an injector robot and mounting it on a boat elevator in a furnace, without spending extra money to assemble other assistant elevator. Hence, the injector robot could be moved smoothly in the vertical direction by the supporting of the boat elevator in the furnace. 
     According to the above objects, the present invention is providing an injector robot for replacing a gas injector in a furnace. The injector robot is composed of a base placed on the boat elevator, a slide rail arranged on the base, and a support stand mounted to the slide rail. The top of the support stand is provided with a notch structure used to hold the gas injector, and then a chuck fixed to the support stand will help to stabilize the gas injector. In addition, the slide rail is used to provide a horizontal-moving track for the support stand. Hence, by the above designs and the utilization of the boat elevator, the injector robot could execute the gas injector replacement process in the furnace, and which is still running and without any cooling and reheating action as in the conventional replacement processes. 
     Additional objects and advantages of this invention will be apparent from the following detailed description of a preferred embodiment thereof that proceeds with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a schematic structure of a vertical furnace. 
     FIG. 2 illustrates a schematic structure of an injector robot arranged in a vertical furnace. 
     FIG.  3 A and FIG. 3B illustrate the schematic solid structure of another injector robot arranged to pull out a gas injector from a gas supply. 
     FIG. 3C illustrates a top view of another injector robot. 
     FIG. 3D illustrates a solid structure of an upper support arm. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference is now made to FIG. 2, which is a schematic structure of an injector robot arranged in a vertical furnace  200  in accordance with one embodiment of the present invention. The vertical furnace  200  is equipped with a thermal insulating cover  202  in it. Within the internal space of the thermal insulating cover  202 , an outer quartz tube  204 , an inner quartz tube  206  and a plurality of heaters  208  are arranged to form a process tube  210  with a cylindrical space. Various reaction gases used in the process tube  210  are introduced by gas supply conduits  212  and gas injectors  216  and finally are discharged by gas exhaust conduits  214 . 
     As shown in FIG. 2, the injector robot is mounted on a platform  218  of the boat elevator  220 , which is used for transporting the boat in the vertical furnace  200 . Hence, in this preferred embodiment, the injector robot will be able to move vertically by the assistance of the boat elevator  220 . But according to the present invention, other elevators (not shown) with the ability to transport the injector robot moving vertically could also be arranged in the present invention. The injector robot is composed of a base  224  placed on the platform  228 , a slide rail  234  arranged on the base  224 , and a support stand  236  mounted to the slide rail  234 . The slide rail  234  is used to provide a horizontal-moving track for the support stand  236 . A notch structure is provided on the upper section of the support stand  236 , it is used to hold the partial section of the gas injector  216 . In this embodiment, the gas injector is a L-shape structure, hence, a L-shape notch structure is provided on the upper section of the supporting stand  236  and then the corner section of the gas injector  216  will be held within the L-shape notch structure of the top section of the supporting stand  236 . After the combination of the gas injector  216  and the support stand  236 , a chuck  246 , fixed on the supporting stand  236  with a fixing means such as hexagon bolt  248 , is provided with a stabilizing baffle to prevent the gas injector  216  escaping from the support stand  236 . 
     Reference is now made to FIG.  3 A and FIG. 3B, which illustrate the schematic solid structure of an injector robot arranged to pull out a gas injector  316  from a gas supply conduit  312  in a furnace (not shown) in accordance with another embodiment of the present invention. First, referring to FIG. 3A, the injector robot, mounted on a platform  318  of the boat elevator (not shown), is composed of a level-adjusting means  326 , a base  324 , an rotary disk  332 , a slide rail  334  and a support stand  336  from bottom to top. In this embodiment, the level-adjusting means  326  is used to avoid the injector robot having a sloping tendency by controlling the relative length of three adjusting screws  328 , and the three adjusting screws  328  are arranged between a connection disk  330  and the base  324 . But other adjusting mechanisms could also be utilized to correct the level of the injector robot according to the present invention. Besides, the connection disk  330  mounted on the platform  318 , is not only arranged to make a fixed connection with the platform  318 , according to the present invention, but, the connection disk  330  could be arranged to become a rotary disk by the assistance of a cylindrical-shape structure of the platform  318 . 
     Referring to FIG. 3A, the slide rail  334  is arranged to provide a horizontal-moving track for the support stand  336 , and the rotary disk  332  will be controlled to rotate the slide rail  334  toward a specific direction for pulling out the gas injector  316  from the gas supply conduits  312  in the furnace. Hence, the injector robot could execute the replacement of the gas injector  316  precisely by the cooperation of the boat elevator, the slide rail  334 , the rotary disk  332  and the level-adjusting means  326 . In this embodiment, the support stand  336  is composed of a support arm  342  and a support base  338 . The support base  338  is mounted on the slide rail  334 , and a fixing means such as hexagon bolt  340  could be used to fix the support base  338  with the slide rail  334 . And the bottom of the support arm  342  is fixed with the support base  338  by another fixing means such as screws  344 . Hence, by the separable design of the support base  338  and the support arm  342 , the support stand  336  could be applied to various specifications of the gas injector  316  by exchanging other proper support arms  342 . 
     Before taking the gas injector  316  apart from the gas supply conduit  312 , the boat elevator is operated to transport the injector robot upward to a predetermined height and the rotary disk  332  is operated to rotate the slide rail  334  paralleling the gas supply conduit  312 . Referring to FIG. 3A, the corner section of the gas injector  316  is held in the L-shape notch structure of the upper support arm  342 A by a proper horizontal movement of the support base  338 . However, the L-shape notch structure of the upper support arm  342 A is only arranged to hold the gas injector  316  so that a chuck (not shown) provided with a stabilizing baffle is used to prevent the gas injector  316  from escaping from the notch structure of the upper support arm  342 A according to the present invention. 
     FIG. 3B illustrates the separated situation between the gas injector  316  and the gas supply conduit  312 . The gas injector  316 , held by the upper support arm  342 A and blocked by a horizontal baffle and a vertical baffle of a chuck  346 , is pulled out horizontally from the gas supply conduit  312 . The chuck  346  is fixed on the sidewall of the support arm  342  by a fixing means such as hexagon bolts  348 . Afterwards, the boat elevator will be operated to transport the injector robot downward to the original height. Hence, a new gas injector could be arranged to insert into the gas supply conduit  312  in reverse order as in the above description. 
     In this embodiment, the L-shape notch structure of the upper support arm  342 A and the horizontal and vertical baffles of the chuck  346  are arranged to stabilize the gas injector  316  in them, but other fixing mechanisms of the upper support arm  342 A and the chuck  346  could also be arranged in the injector robot to fix the gas injector according to the present invention. Comparing with the circular-arc profile of the L-shape notch structure of the upper support arm  342 A, FIG. 3D illustrates a solid structure of a rectangular profile of the L-shape notch structure of another upper support arm  342 B. Besides, according to the present invention, the relative positions of the base  324 , the level-adjusting means  326  and the rotary disk  332  are not limited as in this preferred embodiment. 
     A top view of the injector robot according to this embodiment is shown in FIG.  3 C. In this embodiment, a scale  350  could be provided on the rotary disk  332  and parallel with the slide rail  334  for measuring the horizontal movement distance of the support base  338 . Besides, two levels  352 , one is parallel with the slide rail  334  and another is perpendicular to the slide rail  334 , are also could be provided on the rotary disk  332  as a correct reference for monitoring the sloping tendency of the injector robot. 
     Skilled workers will further recognize that many changes may be made to the details of the above-described embodiments of this invention without departing from the underlying principles thereof. The scope of the present invention should, therefore, be determined only by the following claims.