Abstract:
A wafer inspection system is provided. The wafer inspection system comprises: a transfer region in which a transfer device is arranged; an inspection region in which test heads for inspecting a substrate are arranged; and a maintenance region in which the test heads are maintained. The inspection region is located between the transfer region and the maintenance region, a plurality of inspection rooms accommodating the test heads are adjacent to each other in the inspection region, and the test heads are configured to be unloaded from the inspection region to the maintenance region.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This is a divisional application of U.S. patent application Ser. No. 14/525,431, filed on Oct. 28, 2014 which claims the benefit of Japanese Patent Application No. 2013-224460 filed on Oct. 29, 2013, the entire disclosures of which are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The embodiments described herein pertain generally to a wafer inspection system, a wafer inspection apparatus and a prober. 
       BACKGROUND 
       [0003]    There has been used a prober as a wafer inspection apparatus to perform an electrical characteristic test on each of multiple semiconductor devices formed on a semiconductor wafer (hereinafter, simply referred to as “wafer”). The prober includes a probe card facing the wafer, and the probe card includes multiple contact probes as a multiple number of column-shaped contact terminals (see, for example, Patent Document 1). In this prober, a test signal is outputted to a semiconductor device connected to an electrode pad or a solder bump through each of the contact probes of the probe card, so that a conducting state of an electrical circuit of the semiconductor devices can be inspected. 
         [0004]    A test signal is sent to each of the contact probes of the probe card from a test head having a main board as a test circuit. Recently, in order to improve wafer test efficiency, there has been developed a wafer inspection apparatus which includes multiple test heads each having a probe card and inspects a semiconductor device of a wafer with a single test head while the wafer is transferred to another test head. In this wafer inspection apparatus, from the viewpoint of reduction in footprint, cells each accommodating multiple test heads are stacked at multiple levels. 
         [0005]    Since a main board of each test head is a kind of consumables, the main board needs to be regularly replaced. In order to replace the main board, the test head needs to be unloaded from the wafer inspection apparatus to above a maintenance carriage. 
         [0006]    Patent Document 1: Japanese Patent Laid-open Publication No. 2012-063227 
         [0007]    However, the test head has a weight of about 70 kgf and is supported by a slide rail. Thus, it is difficult to move the test head in other directions than in an unloading direction. Therefore, it is necessary to correctly adjust a position of the maintenance carriage to a position of the test head. However, since the maintenance carriage includes a lift device or the like and has a high weight, it is difficult to fine control the position thereof. As a result, it is difficult to unload the test head. 
       SUMMARY 
       [0008]    In view of the foregoing, example embodiments provide a maintenance carriage for a wafer inspection apparatus capable of easily unloading a test head and a maintenance method for the wafer inspection apparatus. 
         [0009]    In one example embodiment, a wafer inspection system is provided. The wafer inspection system comprises: a transfer region in which a transfer device is arranged; an inspection region in which test heads for inspecting a substrate are arranged; and a maintenance region in which the test heads are maintained. The inspection region is located between the transfer region and the maintenance region, a plurality of inspection rooms accommodating the test heads are adjacent to each other in the inspection region, and the test heads are configured to be unloaded from the inspection region to the maintenance region. 
         [0010]    A maintenance carriage which is movable and is configured to support the unloaded test heads may be arranged in the maintenance region. The maintenance carriage may be configured to accommodate the test heads and has a case which is movable up and down, and the case may be allowed to directly face one of the inspection rooms by moving the maintenance carriage and by moving the case up and down. 
         [0011]    A position of the maintenance carriage and a position of the case may be configured to be fixed. A guide rail configured to control a moving direction of the maintenance carriage may be arranged in the inspection region. Each of the plurality of inspection rooms may have an opening facing the maintenance region, and each of the test heads may be configured to be unloaded to the maintenance region via the opening. 
         [0012]    In another example embodiment, a wafer inspection apparatus is provided. The wafer inspection apparatus comprises: a plurality of inspection rooms comprising test heads to be maintained for inspecting a substrate on which a semiconductor device is formed and a guide rail for unloading the test heads to be maintained to a maintenance region; and a loader configured to transfer the substrate into one of the inspection rooms. The plurality of inspection rooms are arranged at a cell tower between the loader and the maintenance region, and the loader and the maintenance region are arranged at opposite sides of the cell tower. 
         [0013]    In another example embodiment, a wafer inspection apparatus is provided. The wafer inspection apparatus comprises: a plurality of inspection rooms comprising test heads to be maintained for inspecting a substrate on which a semiconductor device is formed and a guide rail for unloading the test heads to be maintained to a maintenance region; and a loader configured to transfer the substrate into one of the inspection rooms. The plurality of inspection rooms are arranged between the loader and the maintenance region, and the loader and the maintenance region are facing to each other across the plurality of inspection rooms. 
         [0014]    In another example embodiment, there is provided a prober for inspecting electrical characteristics of a semiconductor device formed on a substrate. The prober comprises: a probe card facing the substrate and having a plurality of probes; test heads arranged at an opposite side of the substrate with respect to the probe card; a lifting device configured to move the test heads up and down in a vertical direction; and a guide rail configured to unload the test heads in a direction perpendicular to the vertical direction. 
         [0015]    In accordance with the example embodiments, after a position of the carriage base is fixed and the case is moved up to a position of the test head to be maintained to be fixed, the position of the case can be fine controlled in the horizontal direction. Therefore, the case can directly face the test head to be maintained. As a result, it is possible to easily unload the test head toward the case. 
         [0016]    The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    In the detailed description that follows, embodiments are described as illustrations only since various changes and modifications will become apparent to those skilled in the art from the following detailed description. The use of the same reference numbers in different figures indicates similar or identical items. 
           [0018]      FIG. 1  is a perspective view schematically showing a configuration of a wafer inspection apparatus to which a maintenance carriage is applied in accordance with an example embodiment; 
           [0019]      FIG. 2A  and  FIG. 2B  show components included in each cell of a cell tower of  FIG. 1 , and to be specific,  FIG. 2A  is a perspective view of a test head, and  FIG. 2B  is a front view illustrating an arrangement of the test head, a pogo frame, and a probe card in each cell; 
           [0020]      FIG. 3A  and  FIG. 3B  schematically illustrate a configuration of the maintenance carriage in accordance with the present example embodiment, and to be specific,  FIG. 3A  is a side view thereof, and  FIG. 3B  is a front view thereof; 
           [0021]      FIG. 4A  and  FIG. 4B  schematically illustrate configurations of a lifter and a test head case of  FIG. 3A  and  FIG. 3B , and to be specific,  FIG. 4A  is a side view thereof, and  FIG. 4B  is a front view thereof; 
           [0022]      FIG. 5  is a partially enlarged view showing a movable fit between a guide unit and a guide rail; 
           [0023]      FIG. 6A  and  FIG. 6B  are side views schematically illustrating a configuration of a simple maintenance carriage, and to be specific,  FIG. 6A  illustrates a case where maintenance is conducted on a test head of a first-level cell in the cell tower, and  FIG. 6B  illustrates a case where maintenance is conducted on a test head of a second-level cell in the cell tower; 
           [0024]      FIG. 7A  to  FIG. 7C  are process diagrams for explaining a maintenance method for a wafer inspection apparatus with the maintenance carriage of  FIG. 3A  and  FIG. 3B ; and 
           [0025]      FIG. 8  is a front view illustrating a modification example of arrangement of the maintenance carriage of  FIG. 3A  and  FIG. 3B . 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    In the following detailed description, reference is made to the accompanying drawings, which form a part of the description. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. Furthermore, unless otherwise noted, the description of each successive drawing may reference features from one or more of the previous drawings to provide clearer context and a more substantive explanation of the current example embodiment. Still, the example embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings, may be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein. 
         [0027]    A maintenance carriage for a wafer inspection apparatus in accordance with the present example embodiment will be explained first. 
         [0028]      FIG. 1  is a perspective view schematically showing a configuration of a wafer inspection apparatus to which a maintenance carriage is applied in accordance with the example embodiment. 
         [0029]    A wafer inspection apparatus  10  of  FIG. 1  includes a cell tower  12  in which multiple inspection rooms (cells)  11  are arranged at multiple levels, for example, at four levels; and a loader  13  which is arranged to be adjacent to the cell tower  12  and configured to load and unload wafers with respect to respective cells  11  with a transfer device (not illustrated) provided therein. Each of the cell tower  12  and the loader  13  has a rectangular parallelepiped having a height of, for example, 2.4 m. 
         [0030]    In the wafer inspection apparatus  10 , at an opposite side (hereinafter, referred to as “outside”) to a surface of the cell tower  12  adjacent to the loader  13 , a space available for maintenance of each cell  11  by an operator is secured, and a maintenance carriage  27  to be described later is arranged therein. 
         [0031]      FIG. 2A  and  FIG. 2B  show components included in each cell of the cell tower of  FIG. 1 , and to be specific,  FIG. 2A  is a perspective view of a test head, and  FIG. 2B  is a front view illustrating an arrangement of the test head, a pogo frame, and a probe card in each cell. 
         [0032]    A test head  15  depicted in  FIG. 2A  includes a main body  16  formed of a rectangular parallelepiped housing and a flange  17  protruding from an upper portion of a side surface of the main body  16  in a longitudinal direction thereof toward the side direction thereof. The main body  16  accommodates a main board (not illustrated) as a test circuit. 
         [0033]    Further, as depicted in  FIG. 2B , in each cell  11 , the test head  15 , a probe card  18 , and a pogo frame  19  configured to support a pogo pin (not illustrated) electrically connecting the probe card  18  and the main board are provided. Sealing members  20  and  21  are arranged between the probe card  18  and the pogo frame  19  and between the pogo frame  19  and the test head  15 , respectively. Since spaces surrounded by the sealing members  20  and  21  are depressurized, the probe card  18  and the pogo frame  19  are vacuum-attracted and attached to the test head  15 . 
         [0034]    The probe card  18  includes a circular plate-shaped main body  24  and multiple contact probes  25  as a multiple number of column-shaped contact terminals arranged to protrude from a lower surface of the main body  24  toward a lower side in the drawing. When a wafer (not illustrated) is brought into contact with the probe card  18 , each of the contact probes  25  is brought into contact with an electrode pad or a solder bump (not illustrated) of each semiconductor device formed on the wafer. 
         [0035]    Returning back to  FIG. 1 , a maintenance opening  26  is formed the outside of each cell  11 , and the test head  15  is unloaded through this maintenance opening  26 . The operator may unload a used main board from the unloaded test head  15  and provide a new main board to the test head  15 . 
         [0036]    Since the test head  15  has a weight of about 70 kgf, it is difficult for the operator alone to handle the test head  15 . Therefore, the test head  15  is supported via the flange  17  by a slide rail (not illustrated) provided along a longitudinal direction of the test head  15  (hereinafter, simply referred to as “longitudinal direction”) within the cell  11  and unloaded in the longitudinal direction by multiple balls provided on an upper surface of the slide rail. 
         [0037]    In order for the operator to easily replace a main board in the wafer inspection apparatus  10 , a supporting device to support the unloaded test head  15  is needed. Therefore, as the supporting device, the maintenance carriage  27  to be described below is provided in the present example embodiment. 
         [0038]      FIG. 3A  and  FIG. 3B  are provided to schematically illustrate a configuration of the maintenance carriage in accordance with the present example embodiment, and to be specific,  FIG. 3A  is a side view thereof, and  FIG. 3B  is a front view thereof. 
         [0039]    The maintenance carriage  27  depicted in  FIG. 3A  and  FIG. 3B  includes a carriage base  29  configured to be supported and moved by multiple rollers  28  (wheels); a lift device  30  provided uprightly from the carriage base  29 ; and a test head case  31  (case) that has a housing shape and accommodates the test head  15 . 
         [0040]    The carriage base  29  is provided with a handle  32 , and the operator can move the maintenance carriage  27  by pushing or pulling the handle  32 . Each roller  28  is formed of a pair of wheels and configured to readily change a direction, so that it is possible to improve the degree of freedom of movement of the maintenance carriage  27 . 
         [0041]    The lift device  30  includes a supporting column  33  extending from the carriage base  29  toward an upper side in the drawing; a lifter  34  provided at the supporting column  33  and configured to move along an extension direction of the supporting column  33 , i.e., in the vertical direction in the drawing; and a motor (not illustrated) configured to move the lifter  34 . 
         [0042]    Further, each roller  28  of the carriage base  29  includes brake (not illustrated), and this brake is unlocked only when the lifter  34  is positioned at the lowermost position in the vertical direction. 
         [0043]      FIG. 4A  and  FIG. 4B  schematically illustrate configurations of the lifter and the test head case of  FIG. 3A  and  FIG. 3B , and to be specific,  FIG. 4A  is a side view thereof, and  FIG. 4B  is a front view thereof. For simple explanation, in  FIG. 4A  and  FIG. 4B , the test head  15  is indicated by dashed lines, and in  FIG. 4B , a slide rail cover  40  to be described later is indicated with a dashed dotted line and the slide rail cover  40  is illustrated in a see-through view. 
         [0044]    As depicted in  FIG. 4A  and  FIG. 4B , the test head case  31  has a rectangular parallelepiped shape, and both ends of the test head case  31  in a longitudinal direction are opened. When the test head  15  is unloaded from the cell  11 , any one of the openings faces the maintenance opening  26  of the cell  11 . The unloaded test head  15  passes through the maintenance opening  26  and is accommodated within the test head case  31 . Further, an upper portion of the test head case  31  is also opened. Therefore, the operator can access the test head  15  accommodated in the test head case  31  through the open upper portion of the test head case  31  and replace a main board through this upper portion. 
         [0045]    The test head case  31  is supported by the lifter  34  via a horizontal position adjusting stage  35 . The horizontal position adjusting stage  35  includes a base  35   a  and a moving part  35   b,  which are as circular plate-shaped members and are vertically overlapped. Between the base  35   a  and the moving part  35   b,  multiple ball bearings (not illustrated) are arranged. Thus, the moving part  35   b  can be horizontally moved on the base  35   a.  The base  35   a  is connected with the lifter  34 , and the moving part  35   b  is connected with the test head case  31 . Therefore, the horizontal position adjusting stage  35  can move the test head case  31  horizontally with respect to the lifter  34 . 
         [0046]    Further, in the horizontal position adjusting stage  35 , the moving part  35   b  can be fixed to the base  35   a  by engaging a part of the base  35   a  with a part of the moving part  35   b  by supplying air from the outside. 
         [0047]    Since the moving part  35   b  is moved on the multiple ball bearings, great strength is not required to move the moving part  35   b.  As a result, the test head case  31  can be horizontally and easily moved by the operator. Further, a plate-shaped stopper  36  protrudes from a lower surface of the test head case  31  toward the lower side, and when a horizontal moving amount of the test head case  31  reaches a preset level, the stopper  36  is brought into contact with the base  35   a  of the horizontal position adjusting stage  35 , so that the horizontal moving amount of the test head case  31  can be regulated. 
         [0048]    At both upper portions of side surfaces of the test head case  31  in the longitudinal direction, there is provided a slide rail  37  formed of multiple balls. The slide rail  37  is configured to support the flange  17  of the test head  15  accommodated in the test head case  31 , and the test head  15  is slid on the slide rail  37  in a longitudinal direction of the test head case  31 . 
         [0049]    Further, at both ends of the upper portions of the side surface of the test head case  31  in the longitudinal direction, there are provided stopper units  38  (fixing units). The stopper unit  38  includes a protrudable protrusion-shaped contactor  39 , and when the contactor  39  protrudes to be brought into contact with the flange  17  of the test head  15 , a position of the test head  15  is fixed with respect to the test head case  31 . Further, in the lift device  30 , when the test head  15  is accommodated in the test head case  31 , if the contactor  39  is not brought into contact with the flange  17 , the lifter  34  cannot be vertically moved. 
         [0050]    When the test head  15  is slid in the longitudinal direction of the test head case  31 , the operator may be at risk of getting his/her hand, particularly finger, caught between the flange  17  and the slide rail  37 . Therefore, the slide rail  37  is covered with the slide rail cover  40 . 
         [0051]    In the maintenance carriage  27 , the lift device  30  can fix a position of the test head case  31  at a height where the slide rail  37  of the test head case  31  directly faces the flange  17  of the test head  15  accommodated within a first-level cell  11 , a height where the same slide rail  37  directly faces the flange  17  of the test head  15  accommodated within a second-level cell  11 , a height where the same slide rail  37  directly faces the flange  17  of the test head  15  accommodated within a third-level cell  11 , and a height where the same slide rail  37  directly faces the flange  17  of the test head  15  accommodated within a fourth-level cell  11 . 
         [0052]    Returning to  FIG. 1 , a guide rail  41  is provided at a lower portion of the outside of the cell tower  12 . The guide rail  41  is provided along the longitudinal direction of the cell tower  12  and has a tube-shaped body having a rectangular cross section. At a side wall  41   a  of the guide rail  41  which is opposite to the cell tower  12 , a slit  42  is formed. As depicted in  FIG. 3B , the maintenance carriage  27  includes guide units  43  provided at the carriage base  29 . 
         [0053]    As depicted in  FIG. 5 , the guide unit  43  includes a bracket  43   a  protruding from the carriage base  29  toward an outside thereof; and a roller  43   b  provided at a front end of the bracket  43   a  and configured to be horizontally rotated. The bracket  43   a  enters into the guide rail  41  through the slit  42  of the guide rail  41 , and the roller  43   b  is accommodated within the guide rail  41 . That is, the guide unit  43  is in the movable fit with the guide rail  41 , and in this case, the side wall  41   a  of the guide rail  41  is positioned between the roller  43   b  and the carriage base  29 . 
         [0054]    The above-described maintenance carriage  27  is used to unload the entire of the test head  15 . In performing the maintenance of the test head  15 , there may be no need to unload the entire of the test head  15 . In this case, a simple maintenance carriage  44  configured to mount a part of the test head  15  may be used instead of the maintenance carriage  27  in the wafer inspection apparatus  10 . 
         [0055]      FIG. 6A  and  FIG. 6B  are side views schematically illustrating a configuration of a simple maintenance carriage, and to be specific,  FIG. 6A  illustrates a case where maintenance is conducted to a test head of a first-level cell in the cell tower, and  FIG. 6B  illustrates a case where maintenance is conducted to a test head of a second-level cell in the cell tower. 
         [0056]    As depicted in  FIG. 6A  and  FIG. 6B , the simple maintenance carriage  44  includes a main frame  46  having multiple rollers  45  at a bottom portion thereof; and a maintenance table  47  configured to be vertically moved with respect to the main frame  46 . The maintenance table  47  includes a slide rail  48  formed of multiple balls, and the slide rail  48  is configured to support the flange  17  of the test head  15  of which a part is unloaded. The maintenance table  47  may be fixed at a first height where the slide rail  48  directly faces the flange  17  of the test head  15  accommodated within the first-level cell  11  and a second height where the slide rail  48  directly faces the flange  17  of the test head  15  accommodated within the second-level cell  11 . 
         [0057]    The simple maintenance carriage  44  is greatly simplified and lightweight as compared with the maintenance carriage  27 , and also includes the multiple rollers  45  provided at the bottom portion of the main frame  46 . Thus, the operator can easily adjust a position of the simple maintenance carriage  44 , so that the slide rail  48  of the maintenance table  47  can accurately face the flange  17  of the test head  15  accommodated within the first-level or second-level cell  11 . As a result, it is possible to unload a part of the test head  15  from the first-level or second-level cell  11 . 
         [0058]      FIG. 7A  to  FIG. 7C  are process diagrams for explaining a maintenance method for the wafer inspection apparatus with the maintenance carriage of  FIG. 3A  and  FIG. 3B . 
         [0059]    First, the rollers  43   b  of the guide units  43  are inserted within the guide rail  41  at the end portion of the guide rail  41 . Then, while the rollers  43   b  are inserted within the guide rail  41 , the maintenance carriage  27  is moved approximately to a position of the cell  11  accommodating the test head  15  to be maintained. Thereafter, by operating the brakes of the respective rollers  28  of the carriage base  29 , the maintenance carriage  27  is fixed at the position ( FIG. 7A ). 
         [0060]    Then, the lift device  30  raises the test head case  31  to a height where the slide rail  37  of the test head case  31  directly faces the flange  17  of the test head  15  to be maintained, and a position of the test head case  31  is fixed ( FIG. 7B ). 
         [0061]    Thereafter, the position of the test head case  31  is fine controlled in the horizontal direction by the horizontal position adjusting stage  35  in order for the slide rail  37  to accurately face the flange  17  of the test head  15  to be maintained ( FIG. 7C ), and the present maintenance method is ended. 
         [0062]    In the maintenance carriage  27  in accordance with the present example embodiment, the horizontal position adjusting stage  35  is provided between the lifter  34  of the lift device  30  arranged uprightly from the movable carriage base  29  and the test head case  31  configured to accommodate the test head  15 , and the test head case  31  is horizontally moved with respect to the lifter  34  through the horizontal position adjusting stage  35 . Accordingly, the position of the carriage base  29  is first fixed. Then, the test head case  31  is moved up to the position of the test head  15  to be maintained, and the position of the test head case  31  is fixed. Thereafter, the position of the test head case  31  can be fine controlled in the horizontal direction such that the slide rail  37  can accurately face the flange  17  of the test head  15  to be maintained. As a result, it is possible to easily unload the test head  15  toward the test head case  31 . 
         [0063]    In the above-described maintenance carriage  27 , at the upper portions of the side surfaces of the test head case  31  in the longitudinal direction, there is provided the slide rail  37  on which the test head  15  is slid in the longitudinal direction of the test head case  31 . Further, the slide rail  37  includes the stopper units  38  configured to fix the position of the test head  15 . Thus, the test head  15  accommodated within the test head case  31  can be moved to a desired position within the test head case  31  and fixed at the position. Therefore, it is possible to improve maintenance efficiency of the test head  15 . 
         [0064]    Further, the above-described maintenance carriage  27  further includes the guide unit  43  which is in the movable fit with the guide rail  41  provided at the lower side of the cell tower  12 . Thus, the maintenance carriage  27  can be accurately moved along the cell tower  12 . Therefore, it is possible to reduce a time for adjusting the position of the maintenance carriage  27 . 
         [0065]    Furthermore, in the above-described maintenance carriage  27 , the side wall  41   a  of the guide rail  41  is positioned between the carriage base  29  and the roller  43   b  provided at the front end of the bracket  43   a  protruding from the carriage base  29  toward the side direction thereof. Thus, even if the maintenance carriage  27  is tilted, since the roller  43   b  is engaged with the side wall  41   a  of the guide rail  41 , the maintenance carriage  27  can be suppressed from turning over. 
         [0066]    Although the present disclosure has been explained with reference to the above example embodiments, the present disclosure is not limited thereto. 
         [0067]    By way of example, the above-described maintenance carriage  27  is provided only at the outside of the single cell tower  12 . However, as depicted in  FIG. 8 , two cell towers  12  may be arranged such that outsides thereof face each other, and the maintenance carriage  27  may be provided between the two cell towers  12 . In this case, the test head case  31  of the maintenance carriage  27  has the openings at both ends in the longitudinal direction, and each opening faces the maintenance opening  26  of each cell  11  of the wafer inspection apparatus  10 . Thus, all of the test heads  15  of the wafer inspection apparatus  10  can be accommodated within the test head case  31 . Therefore, it is possible to improve maintenance efficiency of the test head  15 . 
         [0068]    From the foregoing, it will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims.