Abstract:
A transfer device of a handler for testing semiconductor devices is provided in which a pitch between each of a plurality of picker heads may be adjusted without replacing a cam plate. The transfer device may include a base part, a plurality of picker heads movably mounted on the base part, and a cam plate movably mounted on the base part and having a plurality of inclined cam grooves formed therein. Each picker head is connected to a corresponding cam groove by a connection part extending therebetween, with an end of each connection part movably coupled to its respective cam groove. A driving unit reciprocates the cam plate so that, as the ends of the connection parts move within the cam grooves, a position of the picker heads may be varied.

Description:
This application claims the benefit of the Patent Korean Application No. P2004-101753, filed on Dec. 6, 2004 which is hereby incorporated by reference as if fully set forth herein. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a handler, and more particularly, to a transfer device of a handler for testing semiconductor device in which a pitch of each head of picker heads for absorbing and transferring semiconductors may be adjusted easily and variously. 
   2. Discussion of the Related Art 
   Generally, Module ICs including memory or non-memory semiconductors on one substrate circuitously and appropriately are released after various steps when manufactured. A handler is a device which automatically transfers the Module ICs such as semiconductors to a process and then tests them. 
   Commonly, after a handler re-installs semiconductors, contained in each user tray of a loading part, in a test tray using a transfer device, a handler transfers the test trays to a test site and then performs a testing. In succession, the handler re-contains the tested semiconductors in user trays of an unloading part according to the test results. 
   However, since pitches between each semiconductor lining up in the user tray are different from pitches between each semiconductor lining up in the test tray, pitches between each head of the picker heads should be varied. 
   That is, in a transfer device, the pitches between each picker head should be varied each into the pitches between each semiconductor in the user tray and/or the pitches between each semiconductor in the test tray. 
   The applicant of the present invention developed a transfer device capable of precisely and rapidly adjusting distances of picker heads in a simple structure without using a complex link. In Korea Patent First Publication 10-0248704 (date of publication: Mar. 15, 2000) is disclosed a device for adjusting each semiconductor pitch of a semiconductor tester wherein a cam shaft or a cam plate having a plurality of cam grooves formed inclined therein is installed and some part of each picker head is relative-movably connected to each cam groove of the cam shaft or the cam plate. In the device for adjusting each semiconductor pitch, when rotating the cam shaft by using a rotatory cylinder or rectilinearly moving the cam plate by a pneumatic cylinder, each picker head relatively moves along each cam groove of the cam shaft, thereby adjusting the pitch between each picker head performed. 
   More specifically, in the device for adjusting each semiconductor pitch there are two pitch adjusting steps. In a first step, when an end of a picker head is located at a first end of a cam shaft or a cam groove of a cam plate, the pitch between each picker head is minimized. In a second step, when a cam shaft is rotated by a rotatory cylinder or a pneumatic cylinder, or a cam plate rectilinearly moves and then an end of a picker head moves into a second end of a cam groove, the pitch between each picker head is maximized 
   However, since a conventional device for adjusting each semiconductor pitch includes only two steps of the maximum distance and the minimum distance for adjusting the pitch between each picker head, the cam shaft or the cam plate should be replaced to the ones corresponding with each semiconductor in case that the kinds and sizes of the semiconductors are varied. 
   In other words, when the kinds or the sizes of the semiconductors to be tested are varied, the pitches between the semiconductors in the user trays and the test trays are also varied. Thus, in case that the cam shaft or the cam plate is not replaced with the one suitable for the semiconductors, pitches between the semiconductors in the user tray and the semiconductors in the test tray do not accord with the pitches between the picker heads, thereby the test not being performed. 
   As a result, conventionally whenever the kinds and/or the sizes of the semiconductors to be tested are varied, the cam shaft or the cam plate is replaced with the one suitable for the semiconductors. Therefore, the replacing process is so complex and difficult that it takes much time and may cause a problem of deteriorating work efficiency and productivity. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention is directed to a transfer device of a handler for testing semiconductor device that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
   An object of the present invention is to provide a transfer device of a handler for testing semiconductor device capable of adjusting a pitch between each picker head absorbing semiconductors as wanted without replacing a cam plate. 
   Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
   To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a transfer device of a handler for testing semiconductor device for detachably securing a plurality of semiconductors and transferring them to a preset location is provided with a base part; a plurality of picker heads for securing/detaching the semiconductors; a cam plate movably mounted in the base part, wherein a plurality of cam grooves is formed inclined; connecting parts for connecting each picker heads with each cam groove, wherein a first side thereof is secured to each picker and a second side thereof is relative-movably connected to each cam groove; and a driving unit for reciprocating the cam plate so as that each connecting part is alternately located in a first discretionary position or a second discretionary position and then each picker head may be varied to a first discretionary position or a second discretionary position. 
   According to an embodiment of the present invention, the driving unit comprises a motor mounted in the base part, being capable of controlling a discretionary location, a power transmission part for converting a power of the motor to a reciprocating motion of the cam plate, and a guide member for guiding the reciprocating motion of the cam plate. 
   according to the present invention, in case that a pitch between each picker head should be adjusted because the kinds or the sizes of the semiconductors tested in a handler are varied, a control signal of a motor driving a cam plate is varied without replacing a cam plate, so that the location of the cam plate may be discretionarily varied, thereby capable of adjusting the pitch of each picker head to a discretionary distance as wanted. 
   It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
       FIG. 1  illustrates a perspective front view showing a structure of an embodiment of a transfer device according to the present invention. 
       FIG. 2  illustrates a rear perspective view of the transfer device in  FIG. 1 . 
       FIG. 3  illustrates a sectional view of key parts of the transfer device in  FIG. 1 . 
       FIG. 4  illustrates a plan view of the transfer device in  FIG. 1 . 
       FIG. 5  illustrates a partial perspective view showing a partial structure of the transfer device in  FIG. 1 . 
       FIGS. 6 to 9  illustrate diagrams each showing an operation example of a transfer device according to the present invention. 
       FIGS. 10 and 11  illustrate front perspective views each showing another embodiment of a transfer device according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
   Referring to  FIGS. 1 through 5 , the detailed description of an embodiment of a transfer device according to the present invention is the following. 
   As shown in  FIGS. 1 through 4 , a transfer device according to the present invention comprises a base part  10  installed movable horizontally to a first to a third shaft of a X-Y gentry robot (not shown) mounted on a body (not shown) of a handler, a plurality of picker heads  20  installed in the base part  10  for absorbing semiconductors by means of a vacuous pressure. The picker heads  20  are arranged in a front and a rear portion of the base part  10 , each comprising eight in two rows. 
   The base part  10  comprises a reciprocating block  11  mounted movably upward/downward on the X-Y gentry robot (not shown), two side plates  12 ,  13  connected perpendicularly in both side ends of the reciprocating block  11 , facing each other, and two base plates  14 ,  15  installed parallel with a predetermined distance there between, both ends thereof connected to the side plates  12 ,  13 . 
   A cam plate  30  is installed movably upward/downward between the base plates  14 ,  15  for adjusting a pitch between each picker head  20 . On the cam plate  30 , a plurality of cam grooves  32  (eight cam grooves in an embodiment) is formed inclined in a diffuse direction from an upper side to a lower side. Cam grooves  32   a  are formed on a front surface of the cam plate  30 . as shown in  FIG. 1 , and cam grooves  32   b  are formed on a rear surface of the cam plate  30 , as shown in  FIG. 2 . 
   Also, a first to a fourth linear motion (LM) guide rail  41  to  44  leading the motion of each picker head  20  in horizontal direction are horizontally mounted on an upside and an downside of each base plate  14 ,  15  in a predetermined distance. Linear motion (LM) blocks  45 ,  46  respectively connected to the picker heads  20  are connected with the LM guide rails  41  to  44  for moving along the LM guide rails. 
   The LM blocks  45  connected with the picker heads  20  uneven numbered from a first side are connected with a first and a third LM guide  41 ,  43  of the LM guide rails, and the LM blocks  46  connected with the picker heads  20  even numbered from a first side are connected with a second and a fourth LM guide rails  42 ,  44  of the LM guide rails. 
   The reason why the LM blocks  45 ,  46  connected with each picker head  20  are alternately connected with the upper sides and the lower sides of the LM guide rails  41  to  44  is to prevent the sizes of the LM blocks  45 ,  46  from interfering adjusting a minimum pitch between each picker head  20 . 
   In other words, just like an embodiment, if the LM blocks  45 ,  46  are connected to the same LM guide rails  41  to  44  in line, the LM blocks  45 ,  46  may be collided each other when adjusting the minimum pitch of each picker head  20 , thereby adjusting the minimum pitch of each picker head  20  not performed, because the width of each LM block  45 ,  46  is bigger than the width of each picker head  20 . 
   Of course, in case that the width of each LM block  45 ,  46  is smaller than the width of each picker head  20 ; only one or two LM guide rail(s) may be used and the LM blocks connected to each picker head  20  may be connected to the same LM guide rails in line. 
   The LM guide rails  35  are installed in an upward and downward direction on both sides of the cam plate  30  for reciprocating the cam plate  30  upward/downward. 
   For reciprocating the cam plate  30  upward/downward, LM guide rails  35  are installed in both sides of the cam plate  30  and a LM blocks  36  wherein the LM guide rails  35  are movably connected are installed in inner sides of the side plates  12 ,  13 . 
   Thus, when an outside power is generated in the cam plate  30  in an upward/downward direction, the LM guide rails  35  receive leading of the LM blocks  36 , thereby the cam plate  30  reciprocating upward/downward smoothly. 
   Also, a servo motor  51  is installed in a first side of the reciprocating block  11  so as to generate a driving power reciprocating the cam plate  30  upward/downward. A power transmission shaft  53  is rotatably installed in an upper end of the reciprocating block  11 . A driving pulley  54  engaged with a shaft  52  of the servo motor  51  by the medium of a belt  55  for receiving a power is installed at a first end of the power transmission shaft  53 . Also, a first upper pulley  56  is connected to a first side of the driving pulley  54  on the same shaft  53  and a second upper pulley  57  is also connected to the opposite side of the first upper pulley  56  on the same shaft  53 . 
   A first lower pulley  58  and a second lower pulley  59  each engaged with the first upper pulley  56  and the second upper pulley  57  are rotatably installed in both sides of a lower end of the reciprocating block  11  by the medium of the first and second power transmission belts  61 ,  62 . 
   The fist and second power transmission belt  61 ,  62  are each connected to both sides of the cam plate  30  by pieces  63 ,  64  of a first and a sccond ball screw  152 . 
   Thus, when a signal is applied to the servo motor  51  and a shaft  52  is rotated in one direction, a power is transmitted to a driving pulley  54  by a belt  55  and then a power transmission shaft  53  and the first and a second upper pulley  56 ,  57  engaged with the power transmission shaft  53  are rotated. Thus, the first and second transmission belts  61 ,  62  reciprocate upward/downward and a cam plate reciprocates upward/downward by means of leading of a LM blocks  36 . 
   As shown in  FIG. 5 , guide holes  14 a are formed as elongated hole shapes in a right-and-left direction on a center portion of the base plates  14 ,  15 . Also, bars  25  of a ball screw (not shown in  FIG. 5 ; see  FIGs. 10-11 ) connected to cam grooves  32  of the cam plate  30  through the guide holes  14 a are connected with each picker head  20 . Rollers  26  are roll- movably installed at the end of each bar  25  for facilitating the relative movement between the cam grooves  32  and the bars  25 . 
   The bars  25  connected to the picker heads  20  of a front of the base part  10  and the connection bars  25  connected to the picker heads  20  of a rear are connected together to the cam grooves  32  of the cam plate  30 , and relatively move synchronously each other, thereby adjusting each pitch between the picker heads  20  uniformly. 
   Unlike an embodiment, cam grooves are formed in both sides of a cam plate to have an opposite phase difference each other, so that adjusting the pitch between each picker head of a front picker head row and each picker head of a rear picker head row may be performed reversely each other. 
   An operation method of a transfer device will be described. 
   Shown in  FIG. 6 , connecting bars  25  connected to each picker head  20  located in a first preset position (P 1 ) of an upper end of cam grooves  32  of a cam plate  30  and then a pitch between each picker head  20  is supposed to maintain the minimum distance (D 1 ). In this state, each picker head  20  of a transfer device vacuously absorbs semiconductors (not shown) on a user tray (not shown) and transfers the semiconductors to the position of a test tray (not shown). 
   In the middle of the transfer device moving, a preset control signal is applied to the servo motor  51  (referring to  FIG. 1 ) through a control part of a handler, and then the servo motor  51  operates. As described above, the power is transmitted to the driving pulley  54  (referring to  FIG. 1 ) by the means of the operation of the servo motor  51  and then the power transmission shaft  53  (referring to  FIG. 1 ) is rotated and in succession the driving of the first and the second power transmission belt  61 ,  62  (referring to  FIG. 1 ) reciprocates the cam plate  30  upward/downward. 
   As shown in  FIG. 7 , connection bars  25  are getting widen along a path of each cam groove  32  according as the cam plate  30  is moving upward to a second preset position P 2 . Thus, each picker head  20  connected to the connection bars  25  is getting widen in a right-left direction along a first to a fourth LM guide rails  41  to  44 , thereby the pitch between each picker head adjusted to the maximum distance D 2 . At that time, the pitch of each picker head  20  is equivalent to the pitch in which the semiconductors in a test tray (not shown) are deposited. 
   Hence, in the state when the pitch between each picker head  20  is adjusted to get widen, a transfer device moves and deposits semiconductors absorbed by the picker heads  20  to the test tray, or when unloading a transfer device vacuously absorbs the semiconductors tested completely in the test tray and transfers them to a user tray for unloading. 
   Thus, in case that the transfer device moves from a test tray position to a user tray position, a predetermined control signal is applied to a servo motor  51  and then the servo motor  51  operates as opposed to the operation described above. As the servo motor  51  operates as opposed, the first and the second power transmission belt  61 ,  62  also operate as opposed. Thus, the cam plate  30  is moving downward to a first preset position P 1  again and then the connection bars  25  are getting narrowed along the path of each cam groove  32 , as shown in  FIG. 6 . 
   Hence, each picker head  20  moves horizontally, thereby the pitch between each picker head  20  adjusted to the minimum distance. 
   When kinds and sizes of semiconductors which will be tested are varied, the pitch between each semiconductor in a user tray and the pitch between each semiconductor in a test tray are also varied. Also, the pitch between each picker head  20  is require to be changed according to each pitch varied. At this time, the user inputs a new control order of a servo motor  51  into a control part according to the kinds of each semiconductor without replacing a cam plate  30 , and then newly converts the operation range of the servo motor  51 , thereby setting up a new distance between each picker head  20 . 
   As shown in  FIG. 8 , when a new control signal is applied to a servo motor  51  the servo motor  51  is driven as opposed to the operation range described above and then the cam plate  30  moves to a third preset position P 3 . 
   Thus, connection bars  25  connected to the picker heads  20  are located not at the highest ends of the cam grooves  32  but at a little lower ends of the cam grooves  32  than the highest. Accordingly, each picker heads  20  may have a different minimum distance D 3  between each other from the one described above. 
   Also, as shown in  FIG. 9 , when another different signal is applied to the servo motor  51  and the cam plate  30  is moving upward to a fourth preset position P 4 , the connection bars  25  of each picker head  20  is located in another different position. At this time, the pitch between each picker head  20  is adjusted to a different maximum distance D 4  from the one described above. 
   In case that each pitch between picker heads  20  is needed to be adjusted again due to the change of the kind and/or the size of the semiconductors which will be tested, the user converts a control signal of the servo motor  51  without replacing a cam plate. Hence, the user discretionarily adjusts a moving position of the cam plate, in other words, a relative position between the connection bars  25  and the cam grooves  32 , thereby capable of adjusting the pitch between the picker heads  20  into the discretionary pitch he/she wants. 
   In the embodiment of the transfer device described above, a servo motor  51 , a plurality of pulleys  56  to  59 , power transmission belts  61 ,  62  are employed as a driving means for reciprocating the cam plate  30  upward/downward, but the cam plate  30  may be reciprocated upward/downward by means of using a linear motor of a rectilineal figure having a mover and a stator. 
   Also, power transmission belts and pulleys as described above are employed as a power transmission system for transmitting the power of the servo motor  51 , but ball screws also may be employed. 
     FIGS. 10 and 11  are showing an embodiment of a transfer device using a ball screw as a power transmission system. LM guide rails  141  and LM blocks  142  are installed on a rear base plate  111  for guiding the rightward and leftward motion of a plurality of picker heads  120 . 
   A front base plate  112  of a square frame shape with a center thereof opened is installed parallel spaced apart in front of the rear base plate  111 . A cam plate  130  is installed movable upward/downward in rear of the front base plate  112 . A plurality of cam grooves  132  is formed on the cam plate  130 , extended inclined in a diffuse direction from an upper side to a lower side. 
   In each cam groove  132 , rollers  126  connected correspondingly to each picker head  120  are installed. The rollers  126  roll and contact an inner circumferential surface of each cam groove  132 . 
   In an upper portion of the front base plate  112 , a servo motor  151  is installed capable of controlling a position to a discretionary position. Also, in a front portion of the front base plate  112 , a ball screw  152  is installed in an upward and downward direction. A nut part  153  moving along the ball screw  152  by means of rotation of the ball screw  152  is connected to the ball screw  152 . The nut part  153  is connected to the front side of the cam plate  130  through the opening of the front base plate  112 . The upper end of the ball screw  152  is connected to a servo motor  151  by a belt  155  to receive the power. 
   Hence, when a predetermined signal is applied to the servo motor  151 , the power is transmitted to the ball screw  152  by the belt  155 , after that the ball screw  152  is rotated at a predetermined amount and then the nut part  153  reciprocates upward/downward along the ball screw  152 , thereby reciprocating the cam plate  130  upward/downward. 
   Each picker head  120  moves leftward/rightward along each LM guide rail  141  and the pitch between each picker head  120  is varied. The pitch adjustment of each picker head  120  by means of the cam plate  130  reciprocating upward/downward is almost the same as that of the described embodiment, thereby omitting the detailed description. 
   According to the present invention, in case that the distance between each picker head  120  is required to be adjusted, because the kinds or the sizes of the semiconductors tested in one handler are varied, the position of the cam plate may be varied by means of varying a control signal of a motor driving the cam plate without replacing the cam plate. Therefore, the pitch of each picker head may be adjusted to the discretionary pitch as wanted. 
   Accordingly, the working time loss caused by replacing the cam plate may be removed and the productivity may be enhanced drastically. 
   It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.