Abstract:
A semiconductor device handler is provided, in which a test temperature deviation of a semiconductor device caused by heat produced by the semiconductor device itself during testing is compensated for, allowing a test of the semiconductor device to be carried out at an exact temperature, or within an exact temperature range. The semiconductor device handler includes at least one enclosed chamber, a heating/cooling apparatus configured to bring an inside of the at least one chamber to a low or high temperature state, a pushing unit provided within the at least one chamber and configured to push a plurality of semiconductor devices mounted on a test tray into test sockets of a test board located within the at least one chamber for testing, a cooling fluid supplying apparatus configured to supply cooling fluid, a nozzle assembly configured to spray cooling fluid received from the cooling fluid supplying apparatus onto the semiconductor devices fitted to the test sockets, and a control unit configured to control spraying of cooling fluid onto the semiconductor devices during testing to compensate for temperature changes of the semiconductor devices that occur during testing.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to a handler for use in testing semiconductor devices, and more particularly, to a device for compensating for a test temperature deviation in a semiconductor device handler. 
   2. Background of the Related Art 
   In general, memory, or non-memory semiconductor devices, or modules each having memory, and/or non-memory semiconductor devices arranged on a substrate to form a circuit, are subjected to various tests after fabrication before shipment. The semiconductor device handler (hereafter referred to as “handler”) is an apparatus for automatic transportation of the semiconductor devices or the modules during testing. The handler carries out a process in which, when a loading stacker receives trays having the semiconductor devices or modules held therein, a picker robot transports the semiconductor devices or modules to be tested to a test site, fits them into test sockets, carries out required tests, transports the tested semiconductor devices or modules to an unloading stacker, and unloads the semiconductor devices or modules on designated trays according to a result of the test in order to classify the semiconductor devices or the modules. 
   In general, many handlers have a system for carrying out, not only general performance tests at room temperature, but also tests at high or low temperatures in which an extreme high or low temperature environment is formed by providing an electric heater, or a liquefied gas spray system, within an enclosed chamber. The semiconductor devices or modules are tested to determine if the semiconductor devices or modules can carry out regular performance under the extreme temperature condition. 
   However, in carrying out a test using a handler which facilitates the temperature test of the semiconductor device, the semiconductor device itself generates heat during the time the semiconductor device electrically connected to the test socket is tested. This added heat impedes conducting a test at an exact preset temperature. This is a problem that must be solved for both test and actual application environments as the semiconductor devices become smaller and packing density increases. 
   For example, in a high temperature test, if a user sets a temperature of an inside of the chamber to 80° C. for the test, if there is no heat generated by the semiconductor device itself, the test can be carried out at the set temperature of 80° C. However, if heat is generated by the semiconductor device during the test, causing a test temperature deviation of approx. 15° C. results, the test is carried out at 95° C. instead of at the desired temperature of 80° C. 
   Accordingly, the test of the semiconductor device is carried out at a temperature higher than the set temperature. This results in a drop in yield and reliability as the test at the desired exact temperature or within the desired temperature range failed. 
   SUMMARY OF THE INVENTION 
   An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter. 
   Accordingly, the invention is directed to a device for compensating for a test temperature deviation in a handler that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
   To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a semiconductor device handler is provided which includes at least one enclosed chamber, a heating/cooling apparatus configured to bring an inside of the at least one chamber to a low or high temperature state, a pushing unit provided within the at least one chamber and configured to push a plurality of semiconductor devices mounted on a test tray into test sockets of a test board located within the at least one chamber for testing, a cooling fluid supplying apparatus configured to supply cooling fluid, a nozzle assembly configured to spray cooling fluid received from the cooling fluid supplying apparatus onto the semiconductor devices fitted to the test sockets, and a control unit configured to control spraying of cooling fluid onto semiconductor devices during testing to compensate for temperature changes of the semiconductor devices that occur during testing. 
   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 objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements and wherein: 
       FIG. 1  is a schematic plan view of a handler having a device for compensating a test temperature deviation in accordance with an embodiment of the invention; 
       FIGS. 2A and 2B  are schematic side sectional views of a test site of the handler of  FIG. 1 ; 
       FIG. 3  is a block diagram of a device for compensating for a test temperature deviation in accordance with the invention; 
       FIG. 4  is a schematic front view of a mixer in a device for compensating for a test temperature deviation in accordance with an embodiment of the invention; 
       FIG. 5  is a schematic perspective view of the mixer of  FIG. 4 ; 
       FIG. 6  is a schematic sectional view of the mixer of  FIG. 4  explaining operation of the mixer; 
       FIG. 7  is a schematic front view of the atomizing member in the mixer of  FIG. 4 ; 
       FIG. 8  is a schematic sectional view of a mixer in a device for compensating for a test temperature deviation in accordance with another embodiment of the invention; 
       FIG. 9  is a schematic front view of the atomizing member in the mixer of  FIG. 8 ; 
       FIG. 10  is a schematic sectional view of a filter assembly in a device for compensating for a test temperature deviation in accordance with an embodiment of the invention; 
       FIG. 11  is a schematic sectional view of a filter assembly in a device for compensating for a test temperature deviation in accordance with another embodiment of the invention; and 
       FIG. 12  is a schematic sectional view of a filter assembly in a device for compensating for a test temperature deviation in accordance with another embodiment of the invention. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings.  FIG. 1  is a schematic plan view of a handler having a device for compensating a test temperature deviation in accordance with the invention.  FIGS. 2A and 2B  are schematic side sectional views of a test site of the handler of FIG.  1 . 
   The handler and its operation will be explained as follows. 
   The handler shown in  FIG. 1  includes a loading unit  10  in a front portion of the handler  1 , in which user trays may be loaded, and an unloading unit  20  to one side of the loading unit  10 , in which tested semiconductor devices may be loaded on the user trays, with the tested semiconductor devices classified according to a result of the test(s). 
   Buffer units  40  are provided on both sides of a middle position of the handler  1 . The buffer units  40  temporarily retain the semiconductor devices transported from the loading unit  10 . An exchange unit  50  is provided between the buffer units  40 . The exchange unit  50  takes the semiconductor devices to be tested from the buffer units  40  and places them in a test tray T. The exchange unit  50  also returns the tested semiconductor devices from the test tray T to the buffer units  40 . 
   One or more first picker robot(s)  31  and second picker robot(s)  32  are provided between the front portion of the handler  1  having the loading unit  10  and the unloading unit  20 , and the middle portion of the handler  1  having the exchange unit  50  and the buffer units  40 . Each picker unit  31 ,  32  is linearly movable in the X-Y axes directions and picks up the semiconductor devices. The first picker robot(s)  31  move(s) between the loading unit  10 , the unloading unit  20 , and the buffer units  40  to transport the semiconductor devices. The second picker robot(s)  32  move(s) between the buffer units  40  and the exchange unit  50  to transport the semiconductor devices. 
   A chamber unit  70  is provided in a rear portion of the handler  1  and includes sealed chambers. One or more of the chambers may be fitted with an electric heater or a liquefied gas spraying system (not shown) to form a high or low temperature environment for testing semiconductor devices, which are placed within the respective chamber on the tray T and which are then subjected to testing in the respective high or low temperature environment. 
   In the embodiment of  FIG. 1 , the chamber  70  includes a pre-heat chamber  71 , a test chamber  72 , and a defrost chamber  73 . In the pre-heat chamber  71 , the test trays T transported from the exchange unit  50  are heated or cooled to a preset temperature while being moved step by step from a front portion thereof to a rear portion thereof. In the test chamber  72 , the semiconductor device(s) positioned on the test trays T are fitted to test sockets  86  on a test board  85  (called a Hi-Fix) connected to an external test apparatus  80  and are then tested at the preset temperature. In the defrosting chamber  73 , which is at one side of the test chamber  72 , the tested semiconductor device(s) are restored to an initial room temperature. The pre-heat chamber may heat or cool the test trays T to a preset temperature while moving the test trays through the test chamber  72  step by step from a rear part thereof to a front part thereof. 
   As shown in  FIGS. 2A and 2B , a pushing unit  90  is provided in the test chamber  72  for pushing the semiconductor device(s) attached to a carrier C on the test tray T toward the test board  85  for fitting/removing the semiconductor device(s) to/from the test socket  86 . The pushing unit  90  includes a nozzle assembly  170  fixed thereto for spraying a cooling fluid mixture of dry air and liquid gas, such as liquid nitrogen. As shown in  FIGS. 2A ,  2 B, and  3 , the nozzle assembly  170  includes a plurality of nozzles  170 A which may be individually controllable. The cooling fluid compensates for any temperature deviation by cooling the semiconductor device(s) under test. 
   Moreover, heat sink(s)  180 , such as aluminum heat sinks, may be provided adjacent to the test sockets  86  of the test board  85 . Alternatively, the heat sinks may be provided on the test tray T. The heat sink(s)  180  are brought into surface to surface contact with the semiconductor device(s) S to cool down the semiconductor device(s), thereby compensating for test temperature deviation together with the nozzle assembly  170 . 
   The heat sink(s)  180  may have a built-in temperature sensor  181 . The temperature sensor  181  detects and transmits a temperature to a control unit  190  (see FIG.  3 ). Alternatively, the temperature sensor may be provided on or in the carrier C, the test tray T, the pushing unit  90 , or any other location in which it can sense a temperature, temperature change and/or temperature change rate of a semiconductor device before, during, or after testing. The temperature sensor may also be provided on or as part of the test board  85 . In one embodiment, the heat sink(s)  180  each include a heat pipe (not shown) filled with refrigerant for heat dissipation. 
     FIG. 3  is a schematic diagram of a device for compensating for a test temperature deviation in accordance with an embodiment of the invention. Referring to  FIG. 3 , the device  100  includes a fluid source  110  that supplies liquid gas, such as liquid nitrogen LN 2 , a dry air source  120  that supplies dry air, a mixer  130  connected both to the liquefied gas source  110  and the dry air source  120 . The mixer  130  mixes the liquefied gas and the dry air uniformly to form a cooling fluid, and supplies the cooling fluid to the nozzle assembly  170 . 
   A first solenoid valve  150  is provided on a flow line connecting the liquid gas source  110  and the mixer  130 . The first solenoid valve  150  controls a flow of the liquid gas supplied to the mixer  130 . A second solenoid valve  160  is provided on a flow line connecting the dry air source  120  to the mixer  130 . The second solenoid valve  160  controls a flow of dry air to the mixer  130 . The first and second solenoid valves  150  and  160  are operated by the control unit  190  which electrically controls operation of the handler. The control unit  190  may control spraying of cooling fluid by controlling the spray rate of cooling fluid, a period of time that cooling fluid is sprayed, and/or the proportions of gases in the cooling fluid. 
   Referring to  FIGS. 4-6 , the mixer  130  includes a liquefied gas distribution header  131  connected to an end of a supply tube  161  connected to the liquefied gas source  110 , for receiving a liquefied gas, such as liquefied nitrogen, four solenoid valves  132  and four liquefied gas guide tubes  133 , and a mixer body  134  connected to ends of the liquefied gas guide tubes  133 . The solenoid valve  132  controls a flow rate of the liquefied gas supplied from the liquefied gas distribution header  131  to the mixer body  134  through the liquefied gas guide tubes  33 . 
   In the exemplary embodiment shown in  FIG. 4 , there are four dry air supply tubes  162  connected between the dry air source  120  and the mixer body  134 . The dry air supply tubes  162  supply dry air to the mixer body  134  through the dry air supply tube  152 . There are also four dry air flow passages  136  in the mixer body  134 . Each dry air supply passage  136  has an inlet connected to a dry air supply tube  162  for receiving the dry air, and an outlet connected to a cooling fluid supply tube  163  (see  FIG. 3 ) connected to the filter assembly  140  (see FIG.  3 ). In this embodiment, there are four dry air supply tubes  162  and four dry air supply passages  136 . However, in other embodiments, other numbers of dry air supply tubes and dry air supply passages may also be appropriate. 
   As shown in  FIG. 5 , the liquefied gas guide tube  133  penetrates one side of the dry air flow passage  136  perpendicular thereto at one side of the mixer body  134  such that an end of the liquefied gas guide tube  133  is positioned within the dry air flow passage  136 . A liquefied gas outlet  138  is formed at one end and faces a flow direction of the dry air. The liquefied gas discharge outlet  138  is formed only in the back side of the liquefied gas guide tube  133 , and utilizes a pressure drop region A, i.e., a low pressure region, in the back side of the end of the liquefied gas guide tube  133  caused by the dry air flowing through the dry air flow passage  136 . 
   An atomizing member  139  is fitted across the liquefied gas guide tube  133 . The atomizing member  139  atomizes liquid phase grain of the liquefied gas and includes a plurality of pass through holes  139   b  forming a circular perforated plate  139   a , as shown in FIG.  7 . 
   The atomizing member may be fitted, not to the liquefied gas guide tube  133 , but to the outlet of the dry air flow passage  136 . In that case, the atomizing member may be a net  239   a , as shown in  FIGS. 8 and 9 . This configuration assures smooth flow of the cooling fluid, atomizing the liquefied gas. 
   In the case the atomizing member  139  is fitted, not to the liquefied gas guide tube  133 , but to the outlet of the dry air flow passage  136 , when a supply pressure of the liquefied gas flowing through the liquefied gas guide tube  133  does not drop, the liquefied gas can flow into the dry air flow passage smoothly, facilitating a more uniform mixing of the liquefied gas with the dry air. In the meantime, the filter assembly  140  atomizes large grains of the liquefied gas that pass through the atomizing member  139  or  239  in the mixer  130 , preventing the liquefied gas from being sprayed through the nozzle assembly  170  and stuck to the semiconductor device(s). 
   Referring to  FIG. 10 , the filter assembly  140  includes a substantially cylindrical housing  141 , a cooling fluid inlet  142  and a cooling fluid outlet  143 , which are both provided in a top surface of the housing  141  and connected to cooling fluid supply tubes  163  and  164 , respectively, and a conical gas-liquid separating member  144  provided with the housing  141 . 
   The gas-liquid separating member  144  is attached to a support part  145  at a central portion of an inside floor of the housing  141 , forming a space SP between a bottom portion of the gas-liquid separating member  144  and a floor of the housing  141 . The liquefied gas still in a liquid phase falls down along the gas-liquid separating member  144  into the space SP, as shown in FIG.  10 . 
   The operation of a device for compensating for a test temperature deviation according to an embodiment of the invention will be explained as follows. 
   Upon putting the handler into operation, the inside of the test chamber  72  is brought to a temperature state by the heating/cooling device, such as an electric heater, or a liquefied gas spraying system. Then, when a test tray T having semiconductor device(s) S is transported into the test chamber  72  and is placed between the pushing unit  90  and the test board  85 , the pushing unit  90  moves toward the test board  85 , pushing the semiconductor device(s) S fitted to the carrier C of the test tray T to the test socket  86 , thereby starting the test. 
   In this instance, the semiconductor device(s) S are brought into surface to surface contact with the heat sink(s)  180  of the test socket  86 , and are cooled down. As the semiconductor device test is started, liquefied gas and dry air are supplied from the liquefied gas source  110  and the dry air source  120  to the mixer  130 . The dry air supplied to the mixer  130  is introduced into the dry air flow passage  136  through the dry air supply tube  162 . At the same time, the liquefied gas, supplied from the liquefied gas source  110  via the liquefied gas supply tube  161  passes the liquefied gas distribution header  131  of the mixer, is subjected to flow rate control at the solenoid valves  132 , and is supplied to the liquefied gas guide tube  133 , where, if the atomizing member  139  is fitted on the liquefied gas guide tube  133 , liquid phase grains of the liquefied gas are atomized into fine particles as the liquefied gas passes through pass through holes  139   b , and is guided toward the liquefied gas outlet  138 . 
   As the end of the liquefied gas guide tube  133  is positioned in the dry air flow passage  136 , the end of the liquefied gas guide tube  133  acts as an obstacle against the dry air flow, such that the dry air forms stream lines around the liquefied gas guide tube  133  and a low pressure region A is formed in the vicinity of the back side of the liquefied gas guide tube  133 , i.e., in the vicinity of the liquefied gas outlet  138 , having a low pressure. The atomized liquefied gas supplied to the liquefied gas guide tube  133  flows through the liquefied gas outlet smoothly and is mixed with the dry air due to the pressure difference in the lower pressure region A. 
   In another words, if the low pressure region is not formed at an outer side of the liquefied gas outlet  138 , the supply of the liquefied gas can not smoothly flow due to the pressure of the dry air, which hinders uniform mixing of the cooling fluid. However, since the liquefied gas outlet  138  is formed at the back side of the liquefied gas guide tube  133  in the dry air flow direction, the low pressure region A is formed in the vicinity of the outlet  138 , permitting smooth discharge of the relatively high pressure liquefied gas through the liquefied gas outlet  138  and mixing with the dry air. 
   Eventually, the liquefied gas and the dry air mixed in the dry air flow passage  136  are supplied to the filter assembly  140  through the cooling fluid supply tube  163  connected to the outlet of the dry air flow passage  136 . In this case, if the atomizing member  239  is fitted to the outlet of the dry air flow passage  136 , the cooling fluid flowing through the dry air flow passage  136  is atomized as it passes through the net  239   a  of the atomizing member  239 , before being supplied to the filter assembly  140 . 
   The cooling fluid discharged from the mixer  130  flows through the cooling fluid supply tube  163 , and is introduced into the housing  141  through the inlet  142  to the filter assembly  140 . In the filter assembly  140 , gas and very fine liquid gas particles, which are lightest in the cooling fluid are directly discharged to the cooling fluid supply tube  164  through the outlet  143 , which is a low pressure region, without reaching the gas-liquid separating member  144 , as the gas and very fine liquid particles of the liquefied gas have low kinetic energy. However, the liquid phase of the liquefied gas, with a large grain size, come into contact with the gas-liquid separating member  144  and flow down, as the liquefied gas has a high kinetic energy. 
   The liquid phase of the liquefied gas, which flows down along the gas-liquid separating member  144 , is collected in a collecting part  146 , vaporized slowly, and is then discharged to the cooling fluid supply tube  164  through the outlet  143 . Accordingly, most of the cooling fluid discharged to the cooling fluid supply tube  164  through the filter assembly  140  is gaseous liquefied gas and dry air, and even if a liquid phase of the liquefied gas is contained therein, the particle size is very fine. 
   The cooling fluid of liquefied gas and dry air discharged in fine particles through the filter assembly  140  is sprayed through the nozzle assembly  170  toward the semiconductor device(s) S being tested, and cools down the semiconductor device(s) S. 
   During testing, while the semiconductor device(s) are cooled down by the heat sink(s)  180  and the nozzle assembly  170 , the temperature sensor(s)  181  in the heat sink(s)  180  detect the temperature and transmits the detected temperature to the control unit  190 . The control unit  190  calculates a temperature of the semiconductor device(s) according to a given experimental equation from the temperature transmitted from the temperature senor  181 , and provides a control signal to the first solenoid valve  150  and the second solenoid valve  155 . 
   The first solenoid valve  150  and the second solenoid valve  155 , which are controlled by the control signal from the control unit  190 , control a flow rate of the cooling fluid sprayed from the nozzle assembly  170  by controlling flow rates of the liquefied gas and the dry air supplied to the mixer  130 , thereby maintaining the test temperature of the semiconductor device(s) at an appropriate level. In the meantime, though the dry air flow passage  136 , connected to the dry air source  120 , is built into the mixer body  134  in the foregoing embodiment, alternatively, an exposed dry air guide pipe (not shown) may be provided for flow of the dry air without a case like the mixer body, with the end of the liquefied gas guide tube having the liquefied gas outlet formed therein inserted therein. 
     FIGS. 11 and 12  illustrate another embodiment of the filter assembly. The filter assembly  240  in  FIG. 11  has a bottom of the conical gas-liquid separating member  224  unified with a floor of the housing  241 , and a collecting part  245  in a form of a groove in the floor of the housing  241  on an outer side of a lower portion of the gas-liquid separating part  244  for collecting liquefied gas. 
   Accordingly, like the foregoing filter assembly  140  of the cooling fluid introduced into the housing  241  through the inlet  242 , light gaseous cooling fluid is discharged to the cooling fluid supply tube  164  through the outlet  243 . On the other hand, relatively heavier liquid phase of liquefied gas flows down along an outside surface of the gas-liquid separating member  244 , and is collected in the collecting part  245 , vaporized, and discharged to the cooling fluid supply tube  164  through the outlet  243 . 
   The filter assembly  340  of the embodiment illustrated in  FIG. 12  includes a housing  341  having on one side an inlet  342  connected to the cooling fluid supply tube  163  for introducing the cooling fluid thereto, and a top portion of the other side having an outlet  343  connected to the cooling fluid supply tube  164  for discharging the cooling fluid. The housing  341  is in the form of a diffuser enlarged from the inlet side  342  to the outlet side  343 . 
   When the cooling fluid of mixed dry air and liquefied gas are discharged into the housing  341  through the inlet  342 , fine particles of the liquid phase of the liquefied gas is vaporized as the discharged cooling fluid expands, and is then discharged through the outlet  343  together with the dry air directly. The liquid phase of liquefied gas which is not vaporized due to a large grain size is collected in a lower part of the housing  341 , vaporized as time passes, and is then discharged through the outlet in the upper side. 
   The filter assembly  140 ,  240 , or  340  filters liquid phase of liquefied gas while not interfering with flow of the cooling fluid supplied to the nozzle assembly  170 , and thus does not increase a pressure inside the tube and maintains a fixed pressure, permitting discharge of gaseous cooling fluid through the nozzle assembly  170  at a fixed pressure. 
   As will be evident to those of ordinary skill in the art, the device for compensating a test temperature deviation in a handler, in which a temperature rise caused by heat generation at the semiconductor device itself is suppressed, all tests to be carried out at a user desired exact temperature or within a user desired exact temperature range. 
   Thus, the device for compensating for a test temperature deviation in a semiconductor device handler according to the invention suppresses heat generation by the semiconductor device itself during testing, and allows testing in a desired temperature range resulting in improved test reliability and yield, because cooling fluid of the liquefied gas and the dry air is supplied to the semiconductor device and a heat sink comes into surface to surface contact with the semiconductor device during the semiconductor test, for cooling the semiconductor device. 
   The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the invention. The present teaching can be readily applied to other types of apparatuses. The description of the invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures.