Abstract:
The invention aims to provide substrate treatment equipment that can automatically collect a substrate in a normal condition without needing manual operation. The equipment includes a substrate holder  26  for holding substrates  12  in a multistage manner and a substrate transfer unit  34  for transferring the substrates  12  into the substrate holder  26 , wherein a substrate holding condition of the substrate holder  26  is sensed by a sensing section  60 . The sensing section  60  has photo-sensors  64   a ,  64   b , and sensing waveforms sensed by the photo-sensors  64   a ,  64   b  are compared with a normal waveform. A control section  66  is provided, which controls a substrate transfer unit  34  such that substrates  12  other than at least a substrate  12  that was determined to be abnormal are transferred by the unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a Continuation of application Ser. No. 10/570,156 filed Mar. 27, 2006, which in turn is a National Phase Application of PCT/JP2004/013791 filed Sep. 22, 2004. This application claims the benefit of Japanese Patent Application No. JP 2003-333664, filed Sep. 25, 2003. The entire disclosures of the prior applications are hereby incorporated by reference herein in its entirety. 
     
    
     BACKGROUND 
       [0002]    The invention relates to substrate treatment equipment for treating a substrate of a semiconductor device or the like, and a manufacturing method of the substrate. 
         [0003]    As is generally known, there is equipment as this type of substrate treatment equipment, which has a substrate holder for holding substrates in a multistage manner and a transfer unit for transferring the substrates into the substrate holder, and treats the substrates in a treatment furnace while holding a number of substrates in the substrate holder. 
       SUMMARY 
       [0004]    When the substrates are heated in the treatment furnace, or removed from the treatment furnace and then cooled, abnormal phenomena such as cracks or warps may occur in the substrates due to thermal stress. When the cracks or warps are in such a level that they result in disabling automatic carrying of the substrates by an automatic substrate carrying mechanism, tweezers for taking in and out the substrates may collide with the substrates, and push down the substrate holder, leading to a serious accident such as damage of a quartz component. 
         [0005]    To solve this, a mechanism for sensing a condition of the substrates can be considered to be provided. For example, the sensing mechanism has a photo-sensor provided on the transfer unit, and senses the substrates in the substrate holder by moving the photo-sensor using a vertical shaft of the transfer unit. 
         [0006]    Portions where light is intercepted by the substrates and portions where light is transmitted between the substrates are recorded, and a shift level of the vertical shaft and sensing data of the photo-sensor are used to find whether a substrate pitch is normal with respect to a pitch of the substrate holder which has been known. 
         [0007]    When a substrate drops from a support slot on the support holder due to cracking of the substrate or transfer errors, discrepancy may occur between interception/transmission data of light by the photo-sensor and the recorded data, and a substrate on a support slot at which the discrepancy appeared is determined to be in an abnormal transfer condition. 
         [0008]    Moreover, when the substrate completely drops from a support slot and consequently the substrate does not lie on the support slot on which the substrate is essentially to be held, since light is not intercepted, the substrate can be sensed as a lost substrate. 
         [0009]    After a substrate condition is sensed by the substrate sensing mechanism, a substrate that has been transferred onto the support slot at which an error occurred is manually collected by an operator who has entered the equipment. 
         [0010]    Furthermore, after the substrate has been visually confirmed to be safe, it is automatically transferred by the automatic substrate carrying mechanism. 
         [0011]    Currently, it is an issue to realize a mini-environment by using an L/L device (load/lock device), a N 2  purge device, and an organic filter and the like in order to avoid entering of moisture or particles contained in the air and thus reduce contamination of the substrate in substrate treatment equipment. When an abnormal substrate is manually collected after an abnormal phenomenon is sensed by the substrate condition sensing mechanism as describe above, particles generated from a human body may have adverse effects on a substrate in a normal condition at high possibility. In substrate treatment equipment using the N 2  purge device, an atmosphere within the equipment must be returned to the air to reset the environment such that the operator can enter the equipment. In such a situation, a natural oxidation film on a surface of the substrate can not be reduced, consequently a substrate that has been normally transferred also has a problem in process. 
         [0012]    An object of the invention is to provide substrate treatment equipment that can automatically collect a substrate in a normal condition without needing manual operation. 
         [0013]    To solve the problem, a first feature of the invention is substrate treatment equipment having a substrate treatment chamber, a substrate holder that can be inserted into the substrate treatment chamber and holds substrates in a multistage manner in a substantially vertical direction, a substrate transfer unit for transferring the substrates onto the substrate holder, and a sensing device for sensing a holding condition of the substrate held in the substrate holder; which includes a control device that, in transfer of the substrates, senses the holding condition of the substrates using the sensing device, and controls the substrate transfer unit such that substrates other than a substrate which was determined to be in an abnormal substrate holding condition are transferred by the substrate transfer unit. 
         [0014]    A second feature of the invention is substrate treatment equipment having a substrate treatment chamber, a substrate holder that can be inserted into the substrate treatment chamber and holds substrates in a multistage manner in a substantially vertical direction, a substrate transfer unit for transferring the substrates onto the substrate holder, and a sensing device for sensing a holding condition of the substrate held in the substrate holder; which includes a control device that, in transfer of the substrates, senses the holding condition of the substrates using the sensing device, and controls the substrate transfer unit such that substrates other than a substrate which was determined to be in an abnormal substrate holding condition are transferred by the substrate transfer unit; wherein the control device controls the substrate transfer unit such that substrates other than the substrate determined to be abnormal and at least one of substrates held on and under the substrate determined to be abnormal are transferred by the substrate transfer unit. 
         [0015]    A third feature of the invention is a manufacturing method of a substrate having a step of inserting a substrate holder in which substrates are held in a multistage manner in a substantially vertical direction into a substrate treatment chamber, a step of performing heat treatment to the substrates in the substrate treatment chamber, a step of sensing a holding condition of the substrates held in the substrate holder, and a step of transferring substrates other than a substrate that was determined to be in an abnormal substrate holding condition by a substrate transfer unit. 
         [0016]    A fourth feature of the invention is a manufacturing method of a substrate having a step of inserting a substrate holder in which substrates are held in a multistage manner in a substantially vertical direction into a substrate treatment chamber, a step of performing heat treatment to the substrates in the substrate treatment chamber, a step of sensing a holding condition of the substrates held in the substrate holder, and a step of transferring substrates other than a substrate that was determined to be in an abnormal substrate holding condition by a substrate transfer unit; wherein the substrates are transferred in such a manner that substrates are carried for each of several predetermined number of substrates, and when all the predetermined number of substrates to be carried are determined to be in a normal substrate holding condition, all the predetermined number of substrates are carried together, and when at least one of the substrates is determined to be in an abnormal substrate holding condition, substrates other than the substrate that was determined to be abnormal in the predetermined number of substrates are carried one at a time. 
         [0017]    While control means may control the transfer unit such that all the substrates other than the substrate that was determined to be abnormal are transferred by the transfer unit, it preferably controls the transfer unit such that substrates other than the substrate that was determined to be abnormal and at least one of substrates on and under the substrate are transferred by the transfer unit. 
         [0018]    According to the substrate treatment equipment of the invention, in transfer of substrates, the holding condition of the substrates is sensed, and the transfer unit is controlled such that substrates other than at least a substrate that was determined to be abnormal are transferred by the transfer unit, therefore substrates in a normal condition can be automatically collected, and entering of particles into the equipment or oxidation on the substrates can be prevented. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a perspective view generally showing substrate treatment equipment according to an embodiment of the invention; 
           [0020]      FIG. 2  is a cross section view generally showing the substrate treatment equipment according to the embodiment of the invention; 
           [0021]      FIG. 3  is a cross section view showing a treatment furnace used in the substrate treatment equipment according to the embodiment of the invention and the periphery of the furnace; 
           [0022]      FIG. 4  is a side view showing a substrate transfer unit used in the substrate treatment equipment according to the embodiment of the invention; 
           [0023]      FIG. 5  is a side view showing a substrate holder used in the substrate treatment equipment according to the embodiment of the invention; 
           [0024]      FIG. 6  is views for illustrating an abnormal condition of substrate holding in the substrate treatment equipment according to the embodiment of the invention, wherein (a) is a plane view showing a normal condition, (b) is a front view showing a condition of cracking in a substrate, (c) is a front view showing the substrate holder, and (d) is a side view of the substrate holder; 
           [0025]      FIG. 7  is views for illustrating a sensing method when an abnormal condition of substrate holding is found in the substrate treatment equipment according to the embodiment of the invention, wherein (a) is an illustrative view showing a relation between the abnormal condition of substrate holding and a sensing waveform, and (b) is a plane view of the substrate transfer unit; and 
           [0026]      FIG. 8  is a flowchart showing operation of substrate sensing in the substrate treatment equipment according to the embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0027]    Next, an embodiment of the invention is described according to drawings. 
         [0028]      FIG. 1  and  FIG. 2  show substrate treatment equipment  10  according to the embodiment of the invention. The substrate treatment equipment  10  is vertical-type one for performing diffusion treatment or CVD treatment to a substrate. In the substrate treatment equipment  10 , a load/unload stage  18  for inserting a pod  14  accommodating substrates  12  formed from silicon and the like from the outside into a housing  16  is fixed on a front face of the housing  16 . A cassette shelf  22  for storing the inserted pod  14  is provided within the housing  16 . Moreover, an N 2  purge chamber  24  is provided within the housing  16 . The N 2  purge chamber  24  acts as a carrying area of the substrates  12 , or a space for carrying in and out a substrate holder (boat)  26 . When treatment of the substrate  12  is performed, the N 2  purge chamber  24  is filled with inert gas such as N 2  gas to prevent a natural oxidation film from being formed on the substrate  12 . 
         [0029]    FOUP is used for the pod  14 , and the substrate  12  can be carried while being isolated from the air by covering an opening provided in a side face of the pod  14  by a cap (not shown), and the substrate  12  can be taken in and out into/from the pod  14  by removing the cap. For example,  25  substrates  12  are stored in the pod  14 . A pod opener  28  is provided in a front face of the N 2  purge chamber  24  so that the cap of the pod  14  is removed to communicate the atmosphere within the pod  14  with the atmosphere within the N 2  purge chamber  24 . The pod  14  is carried among the pod opener  28 , cassette shelf  22  and load/unload stage  18  by the cassette transfer unit  30 . Air cleaned by a clean unit (not shown) provided on the housing  16  is flowed through a space for carrying the pod  14  by the cassette transfer unit  30 . 
         [0030]    Within the N 2  purge chamber  24 , a substrate holder  26  for loading a plurality of substrates  12  in a multistage manner, a substrate alignment device  32  for aligning a notch (or an orientation flat) of the substrate  12  to an optional position, and a substrate transfer unit  34  for carrying the substrate  12  between the pod  14  on the pod opener  28  and the substrate alignment device  32  are provided. A treatment furnace  36  for treating the substrates  12  is provided in an upper part of the N 2  purge chamber  24 , and the substrate holder  26  is loaded into the treatment furnace  36  by a boat elevator  38  as elevating means, or unloaded from the treatment furnace  36  by it. The treatment furnace  36  has a furnace port which is closed by a furnace port shutter  40  during except for a period during treating the substrate  12 . 
         [0031]    Next, operation of the substrate processing equipment  10  according to the embodiment is described. 
         [0032]    First, the pod  14  carried from the outside of the housing  16  by AGV or OHT is set on the load/unload stage  18 . The pod  14  set on the load/unload stage  18  is directly carried onto the pod opener  28 , or stocked temporarily on the cassette shelf  22  and then carried onto the pod opener  28  by the cassette transfer unit  30 . When the pod  14  is carried onto the pod opener  28 , the cap of the pod  14  is removed by the pod opener  28 , and thereby the atmosphere within the pod  14  is communicated with the atmosphere within the N 2  purge chamber  24 . 
         [0033]    Then, a substrate  12  is removed from the pod  14  in a condition of being communicated with the atmosphere within the N 2  purge chamber  24  by the substrate transfer unit  34 . The removed substrate  12  is aligned by the substrate alignment device  32  such that the notch or the orientation flat is fixed in an optional position, and after that carried onto the substrate holder  26 . 
         [0034]    When the substrates  12  have been carried into the substrate holder  26 , the furnace port shutter  40  of the treatment furnace  36  is opened, and then the substrate holder  26  having the substrates  12  mounted therein is loaded into the treatment furnace  36  by the boat elevator  38 . 
         [0035]    After loading, predetermined treatment is performed to the substrates  12  in the treatment furnace  36 , and after the treatment, the substrates  12  and the pod  14  are ejected to the outside of the housing  16  in the reverse order of the above procedure. 
         [0036]      FIG. 3  shows a peripheral configuration of the treatment furnace  36 . The treatment furnace  36  has an outer tube  42  formed from a heat resistant material such as quartz (SiO 2 ). The outer tube  42  is in a cylindrical shape that is closed at an upper end and has an opening at a lower end. An inner tube  44  is disposed concentrically within the outer tube  42 . A heater  46  as heating means is disposed concentrically on the outer circumference of the outer tube  42 . The heater  46  is held on the housing  16  via a heater base  48 . 
         [0037]    As shown in  FIG. 4  and  FIG. 5 , in the substrate holder  26 , for example, three poles  50  formed from, quartz, silicon carbide and the like are disposed parallel in a vertical direction, and the substrates  12  are held by support slots  52  formed on the poles  50 . The substrate transfer unit  34  has a transfer unit body  54  that moves vertically and rotates, and a main tweezers body  56  that moves reciprocally on the transfer unit body  54 . For example, four tweezers  58   a ,  58   b ,  58   c  and  58   d  are fixed to the main tweezers body  56  in a manner of extending parallel to one another. Moreover, sub tweezers body  57  is provided on the transfer unit body  54  such that it can reciprocally move either along with or independently of the main tweezers body  56 . Tweezers  58   e  are fixed to the sub tweezers body  57  at a position below the four tweezers  58   a  to  58   d  and parallel to them. Therefore, as shown in  FIG. 4 , the substrate transfer unit  34  can collectively transfer five substrates  12  using the five tweezers  58   a  to  58   e , and can transfer one monitor substrate (sheet transfer) using the tweezers  58   e  at the lowermost stage. When the monitor substrate is transferred, as shown in  FIG. 5 , a space corresponding to one slot is opened between sets of collectively transferred, five substrates  12 , and a monitor substrate  59  is extracted from a pod different from a pod for typical substrates  12 , and inserted between the sets of the five substrates. 
         [0038]    For example,  25  substrates  12  are accommodated in the pod  14 , and in the case that the substrates  12  are transferred into or collected from the substrate holder  26  by the substrate transfer unit  34 , when there is no abnormal substrate in five slots (slot group), five substrates  12  are collectively transferred or collected using the five tweezers  58   a  to  58   e , and when there is an abnormal substrate in the slot group, only normal substrates are collected using the tweezers  58   e  at the lowermost stage. The monitor substrate may be collected one at a time as in insertion. 
         [0039]    A sensing section  60  as sensing means is provided on the transfer unit body  54 . The sensing section  60  has parallel, two arms  62   a ,  62   b , and is provided such that the arms  62   a ,  62   b  can be turned on a side face of the transfer body  54 . Near front ends of the arms  62   a ,  62   b , transmission-type photo-sensors  64   a ,  64   b  are provided, and one of the photo-sensors is a light emitting element, and the other is a light receiving element. When a holding condition of the substrates  12  transferred into the substrate holder  26  is sensed, the arms  62   a ,  62   b  are turned and fixed to a side of the substrate holder  26  so that light axes of the photo-sensors  64   a ,  64   b  run through the substrates  12 , and then sensing output of the photo-sensors  64   a ,  64   b  is monitored while the substrate transfer unit  34  is moved from a lower end to an upper end of the substrate holder  26 . On the other hand, when the substrates  12  are transferred into the substrate holder  26  by the substrate transfer unit  34 , the arms  62   a ,  62   b  are turned to a side opposite to the substrate holder side to prevent the arms  62   a ,  62   b  from being interfered with the substrates  12  or the substrate holder  26 . 
         [0040]    As shown in  FIG. 3 , analog signals outputted from the photo-sensors  64   a ,  64   b  are outputted to a control section  66  including a computer. The control section  66  controls the substrate transfer unit  34  via a driver section  68  such as a motor. 
         [0041]    Next, sensing of the abnormal condition of the substrates  12  is described. 
         [0042]    As shown in  FIG. 6(   a ), it is assumed that the light emitting element  64   a  is situated at the right side, and the light receiving element  64   b  is situated at the left side in a view from a top of the substrate holder  26 , and the light emitting element  64   a  and the light receiving element  64   b  are disposed at a front face side of the substrate holder  26 . As shown in  FIG. 6(   b ), the substrate  12  may crack while being held in the substrate holder  26  or drop from the support slot  52  of the substrate holder  26 , resulting in falling into abnormal condition. As shown in  FIG. 6(   c ) and  FIG. 6(   d ), the abnormal conditions of the substrate  12  are given as follows. 
         [0043]    A. drop/in pairs 
         [0044]    B. drop/light-emitting side drop (left face drop) 
         [0045]    C. drop/light-receiving side drop (right face drop) 
         [0046]    D. drop/rear drop (back face drop) 
         [0047]    E. drop/front drop (front face drop) 
         [0048]    F. cracking/center cracking 
         [0049]    G. cracking/front cracking 
         [0050]    H. cracking/rear cracking 
         [0051]    J. no substrate 
         [0052]    A substrate  12 , which is in the normal condition, is supported parallel to a support slot  52 . 
         [0053]      FIG. 7(   a ) shows a relation of signal output from the photo-sensors  64   a ,  64   b  to the abnormal condition. A positional relation between the substrate holder  26  and the photo-sensors  64   a ,  64   b  is assumed that the photo-sensors  64   a ,  64   b  are at a front side, and a side opposed to the photo-sensors is a back side as shown in  FIG. 7(   b ). 
         [0054]    When the holding condition of the substrates  12  is normal, waveforms outputted from the photo-sensors  64   a ,  64   b  are regular. For example, when a left or right surface of the substrate  12  drops, sensing waveforms of the photo-sensors  64   a ,  64   b  are gradually spread at left and right of a peak compared with a normal waveform, consequently width at a reference line is increased. When the substrate  12  completely drops from the support slot  52 , sensing output of the photo-sensors  64   a ,  64   b  disappears at that support slot  52  from which the substrate has dropped. When the substrate  12  drops from the support slot  52  at the back, the peak is shifted to the upper side compared with the normal waveform. When the substrate  12  drops from the support slot  52  at the front, the peak is shifted to the lower side compared with the normal waveform. The case that the substrate  12  has cracked can be also sensed. 
         [0055]      FIG. 8  shows an example of substrate sensing operation by the control section in a flowchart. 
         [0056]    First, in step S 10 , drive of the substrate transfer unit and the photo-sensors is started. That is, as previously shown in  FIG. 3 , the arms  62   a ,  62   b  are rotationally fixed to the side of the substrate holder  26 , and then a transfer condition of the substrates  12  is sensed by the photo-sensors  64   a ,  64   b  while the substrate transfer unit  34  is raised from the lowermost end of the substrate holder  26  at a constant speed. The quantity of light of light emitting/receiving of the photo-sensors  64   a ,  64   b  is inputted into the control section  66  as analog signals. 
         [0057]    In next step S 12 , the analog signals inputted from the photo-sensors  64   a ,  64   b  are converted into digital signals to analyze detection output from the photo-sensors  64   a ,  64   b . In this analysis of output from the photo-sensors  64   a ,  64   b , the sensing waveforms from the photo-sensors  64   a ,  64   b  are recorded and then compared with the normal waveform so that an abnormal slot is specified and thus an abnormal slot list is prepared. 
         [0058]    In next step S 14 , whether before or after heat treatment is determined. When determination is made as before heat treatment, the operation is advanced to step  16  to determine whether an abnormal slot is found or not, and when it is determined that the abnormal slot is not found, the operation is advanced to step S 18  in which the substrate supporter  26  is carried into the treatment furnace  36 , and then heat treatment is carried out. On the other hand, when determination is made as after heat treatment in the step S 14 , or when it is determined in the step S 16  that the abnormal slot is found, the operation is advanced to step S 20  in which collection of the substrates  12  is started. As described before, the collection of the substrates  12  is performed for each of slot groups, and it is begun at a first slot group and ended at a fifth slot group that is a final slot group. In next step S 22 , whether all the five substrates in the slot group to be collected are transferred in the normal condition (not found in the abnormal slot list) is determined. When all the five substrates are determined to be in the normal condition in the step S 22 , the operation is advanced to step S 24  in which all the five substrates are collected together. On the other hand, when it is determined that there is a substrate in the abnormal condition in the five substrates  12  in an objective slot group (found in the abnormal slot list) in the step S 22 , the operation is advanced to step S 26  in which only the substrates in the normal condition are collected in a manner of sheet transfer. When collection is not completed for all the slot groups in the step S 28 , the operation is returned to processing for a next slot group, and when collection is completed for all the slot groups, the operation is finished. 
         [0059]    In the embodiment, when a substrate in the abnormal condition is found, the substrate in the abnormal condition is remained in the substrate holder, and all the substrates in the normal condition are returned into the pod, however, the invention is not necessarily limited to this. When the substrate in the abnormal condition is found, a substrate on or under the substrate may receive a kind of damage. Thus, it is also acceptable that at least one of substrates on and under the substrate in the abnormal condition is also remained in the substrate holder, and other substrates in the normal condition are returned into the pod. 
       INDUSTRIAL APPLICABILITY 
       [0060]    The invention can be used for substrate treatment equipment that automatically collects substrates.