CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 of Korean Patent Application No. 2006-55560, filed on Jun. 20, 2006, the entire contents of which are hereby incorporated by reference. 
     
     BACKGROUND OF THE INVENTION 
       [0002]    The present disclosure relates to a semiconductor test system and, more particularly, to a semiconductor test system capable of performing a virtual test and a semiconductor test method thereof. 
         [0003]    The semiconductor test system is used to detect defects of a semiconductor device through an electrical test process. The semiconductor test system includes a tester and a prober, or, alternatively, a tester and a handler. 
         [0004]    The semiconductor test system including the tester and the prober is used to remove an initial defect after a wafer manufacturing process. Typically, the prober is a wafer transferring device. The prober transfers the wafer so as to accurately deliver a test signal from the tester into a chip inside the wafer. 
         [0005]    On the other hand, the semiconductor test system including the tester and the handler is used to remove defects after an assembling process. Typically, the handler is a package transferring device. The handler receives a test signal from the tester, and examines a packaged chip. 
         [0006]      FIG. 1  is a block diagram of a conventional semiconductor test system. Referring to  FIG. 1 , a semiconductor test system  10  includes a tester  1  land a prober  12 . The tester  11  generates a test signal for testing a wafer (not shown). The tester  11  provides the test signal into the prober  12 . The prober  12  is a wafer transferring device, and transfers the next wafer when a test for one wafer is completed during a test operation. 
         [0007]    The tester  11  drives the prober  12  to perform a wafer test operation. After reading a wafer test result, the tester  11  needs to be connected to the prober  12  to give an appropriate command depending on the wafer test result. The tester  11  and the prober  12  communicate with each, other through a general purpose interface bus (GPIB) or RS232 (not shown). 
         [0008]    When the tester  11  is not actually connected to the prober  12 , no operation is possible. According to a conventional semiconductor test system, when the tester is developed or the test program is updated, the prober needs to be set up and be connected to the tester. 
       SUMMARY OF THE INVENTION 
       [0009]    Exemplary embodiments of the present invention provide a semiconductor test system capable of a virtual test operation without connecting a prober to a tester, and a semiconductor test method thereof. 
         [0010]    Exemplary embodiments of the present invention provide semiconductor test systems capable of performing a virtual, test without a prober, the semiconductor test systems including: a tester providing a test signal; and an emulator providing a virtual test result to the tester in response to the test signal. The emulator includes virtual prober software to obtain the virtual test result. 
         [0011]    In exemplary embodiments, the emulator further includes test software receiving the test signal and generating a test command, the test software providing the test command to the virtual prober software. The test software and the virtual prober software communicate with each other through the Ethernet. The emulator further includes: a buffer memory storing a virtual test result and an error condition corresponding to the test command; and a monitor notifying a user of an error occurring during a virtual test operation. 
         [0012]    In exemplary embodiments, the virtual prober software includes: an input/output unit receiving the test command and outputting the virtual test result; a process unit performing a virtual test operation in response to the test command; and a control unit controlling the buffer memory and the monitor during the virtual test operation. The control unit controls the monitor to notify a user of an error when there is an error in the test command, or in the virtual test result. The control unit also controls the monitor to notify a user of an error when there is an error in an application program of the virtual prober software, 
         [0013]    According to exemplary embodiments of the present invention, semiconductor test systems include: a tester providing a test signal; a prober performing a wafer test operation; and an emulator performing a virtual test operation through virtual prober software. The emulator controls the prober to perform the wafer test operation in response to the test signal, or controls the virtual prober software to perform the virtual test operation. 
         [0014]    In exemplary embodiments, the emulator further includes test software receiving the test signal and generating a test command, the test software selectively providing the test command to the prober or to the virtual prober software. The test software provides the test command to the virtual prober software when the virtual prober software is enabled. The prober communicates with the emulator through a GPIB (general purpose interface bus). The prober communicates with the emulator through the RS232 standard for serial binary data connection. The test software and the virtual software communicate with each, other through the Ethernet. 
         [0015]    In exemplary embodiments, the emulator further includes: a buffer memory storing a virtual test result and an error condition corresponding to the test command; and a monitor notifying a user of an error occurring during a virtual test operation. The virtual prober software includes; an input/output unit receiving the test command and outputting the virtual test result: a process unit performing a virtual test operation in response to the test command; and a control unit controlling the buffer memory and the monitor during tire virtual test operation. The control unit controls the monitor to notify a user of an error when there is an error in the test command, or in the virtual test result. The control unit also controls the monitor to notify a user of an error when there is an error in an application program of the virtual prober software. 
         [0016]    Exemplary embodiments of the present invention provide semiconductor test methods performing a virtual test operation without a prober, the methods including: generating a test signal by a tester; determining whether virtual prober software is enabled or not; performing a virtual test operation, through the virtual prober software in response to the test signal when the virtual prober software is enabled; and providing a virtual test result to the tester. 
         [0017]    In exemplary embodiments, the method further includes performing a wafer test operation through a prober when the virtual prober software is disabled. 
         [0018]    According to exemplary embodiments, the performing of the virtual test operation includes: confirming an input of the test signal; analyzing the test signal to determine whether there is an error or not; and performing the virtual test operation when there is no error. The method further includes notifying a user of an error when there is an error. 
     
     
       BRIEF DESCRIPTION OF THE FIGURES  
         [0019]    Exemplary embodiments of the present invention will be understood in more detail from the following descriptions taken in conjunction with the accompanying figures, in which; 
           [0020]      FIG. 1  is a block diagram of a conventional semiconductor test system; 
           [0021]      FIG. 2  is a block diagram of a semiconductor test system according to an exemplary embodiment of the present invention; 
           [0022]      FIG. 3  is a block diagram of an operation of virtual prober software used in the system of  FIG. 2 ; 
           [0023]      FIG. 4  is a flowchart of a semiconductor test method according to an exemplary embodiment of the present invention; 
           [0024]      FIG. 5  is a flow-chart illustrating an operation of determining whether there is error in an application program, of virtual prober software in operation S 320  of  FIG. 4 ; and 
           [0025]      FIG. 6  is a flowchart illustrating an operation determining whether there is an error in a virtual test result in operation S 320  of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0026]    Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those of ordinary skill in the art. 
         [0027]      FIG. 2  is a block diagram of a semiconductor test system according to an exemplary embodiment of the present invention. Referring to  FIG. 2 , a semiconductor test system.  100  includes a tester  110 , a prober  120 , and an emulator  130 . According to the semiconductor test system  100 , although the tester  110  does not include the prober  120  therein, it can operate as if connected to the prober  120 . 
         [0028]    The tester  110  in the form of hardware (H/W) applies an electric signal to a semiconductor chip placed on a wafer (not shown) to test electric characteristics of the semiconductor chip. The prober  120  in the form of hardware (H/W) operating as a wafer transferring device places a wafer on an appropriate point of a chuck (not shown). Generally, an electric signal of the tester  110  is transferred into the wafer of the prober  120 , and the tester  110  reads a test result from the prober  120  to determine whether there is a defect on the wafer or not. 
         [0029]    The tester drives the prober  120 , and needs to be actually connected to the prober  120  to examine defects of the wafer. That is, the tester  110  can not read data without the prober  120 , such that it can not perform a normal test operation. The semiconductor test system  100  of this exemplary embodiment of the present invention, however, includes the emulator  130  and can perform a virtual test operation as if there is the prober  120 . 
         [0030]    Referring to  FIG. 2 , the emulator  130  includes a first interface  131  for the tester  110 , and a second interface  132  for the prober  120 . In this exemplary embodiment, the second interface  132  uses a communication method such as a general purpose interface bus (GPIB) or the RS232 standard for serial binary data connection. The emulator  130  further comprises test software  210  (S/W), virtual prober software  210  (S/W), a buffer memory  230 , and a monitor  240 . 
         [0031]    The test software  210  is an operating system software of the tester  110 . The test software  210  receives an electric signal from the tester  110  through the first interface  131 . The test software  210  generates a test command by using the electric signal of the tester  110 . The test command is provided to the prober  120  through the second interface  132  or to the virtual prober software  220 . 
         [0032]    In an exemplary embodiment the test software  210  provides a test command to the virtual prober software  220  when the virtual prober software  220  is in an enable state. In this case, a virtual test operation is performed. When the virtual prober software  220  is in a disable state, however, the test software  210  provides a test command to the prober  120 . In this case, a real test operation is performed. 
         [0033]    The prober software  220  is connected to the test software  210  through the Ethernet. Besides the Ethernet, the prober software  220  may also be connected to the test software  210  through semaphores, a local area network, and a message queue. 
         [0034]    The virtual prober software  220  receives a test command from the test software  210  during a virtual test operation. The virtual prober software  220  performs a virtual test operation in response to the test command. The virtual test result is delivered into the test software  210  again. The virtual prober software  220  emulates the prober  120  as if an actual prober  120  operates. The virtual prober software  220  virtually generates data identical to that from the actual prober  120  and then sends the data into the test software  210 . 
         [0035]    Since the tester  110  determines testing of a device by using data, it can not distinguish an actual test result outputted from the actual prober  120  from a virtual test result outputted from the emulator  130 . A buffer memory  230  of the emulator  130  includes a plurality of commands corresponding to various test signals of the tester  110  and their processed results, such that the emulator  130  emulates the actual prober  120 . 
         [0036]      FIG. 3  is a block diagram of an operation of the virtual prober software  220  of  FIG. 2 . Referring to  FIG. 3 , the virtual prober software  220  includes an input/output unit  221 , a process unit  222 , and a control unit  223 . 
         [0037]    The process unit  221  analyzes the test command inputted through the input/output unit  221 . That is, the process unit  221  determines whether a new test command is inputted from tire input/output unit  221 , and whether the inputted test command is suitable for a predetermined format. The process unit  221  delivers the virtual test result into the input/output unit  221 . 
         [0038]    The control unit  222  controls the buffer memory  230  or the monitor  240  according to the processed result of the process unit  221 . The control unit  222  notifies a user of an error situation when there is an error in an inputted test command or when there is an error in the virtual test result. Although a monitor  240  is illustrated in  FIGS. 2 and 3 , it is apparent to those of ordinary skill in the art that other means, such as an alarm, a printer, and the like can be used for notification. On the other hand, the buffer memory  230  includes various test commands, virtual test process results for respective test commands, and expected error situations. 
         [0039]      FIG. 4  is a flowchart of a semiconductor test method according to an exemplary embodiment of the present invention. Referring to  FIG. 4 , a test method of a semiconductor test system is divided into an actual prober test operation in S 200  and a virtual test operation in S 300 . 
         [0040]    First, the test software  210  of  FIG. 2  will be described. In operation S 110 , the test software  210  receives a test signal from the tester  110  of  FIG. 2 . In operation S 120 , the test software  210  generates a test command in response to the test signal. In operation S 130 , it is determined whether the virtual prober software  220  of  FIG. 2  is in an enable state. 
         [0041]    When the virtual prober software  220  is not in the enable state, that is, No, a test command is applied to the actual prober  120  of  FIG. 2 . In this case, the actual prober operation is performed in operation S 200 . When the virtual prober software  220  is in the enable state, that is, Yes, a test command is applied to the virtual prober software  220 . In this case, a virtual prober test operation is performed in operation S 300 . 
         [0042]    Next an operation of the virtual prober software  220  is described. In operation S 310 , the virtual prober software  220  determines whether a test command is inputted from the test software  210 . An operation S 310  repeats until the test command is inputted, and it proceeds to an operation S 320  when the test command is inputted, 
         [0043]    In operation S 320 , the process unit  222  of  FIG. 3  of the virtual prober software  220  analyzes the test command. The process unit  222  compares the test command stored in the buffer memory  230  of  FIG. 3  to a new inputted test command to verify whether there is an error in the test command itself. 
         [0044]    In this exemplary embodiment, the process unit  222  detects the test result stored in the buffer memory  230  in response to the test command. The process unit  222  verifies whether there is an error in the virtual test result. This will be described in more detail with reference to  FIG. 6 . On the other hand, it is determined whether there is an error in an operating system of the virtual prober software in operation S 320 . This will be described in more detail with reference to  FIG. 5 . 
         [0045]    In operation S 330 , the virtual prober software  220  determines whether there was an error in operation S 320 . When there is an error in operation S 320 , that is, Yes, the control unit  223  of  FIG. 3  sends an error message to the monitor  240 , or whatever other device is used to inform the user. The monitor  240  notifies the user of an error situation, in response to the error message. When there is no error, that is, No, however, the process unit  222  performs the virtual prober test operation S 340 , and sends the virtual test results into the test software  210 . 
         [0046]    In operation S 140 , the test software  210  sends the actual test result provided from the actual prober  120  or tire virtual test result provided from the virtual prober software  220  into the tester  110  and ends. 
         [0047]      FIG. 5  is a flowchart illustrating an operation determining whether there is error in an application program of a virtual prober software in operation S 320  of  FIG. 4 . In operation S 410 , parameters such as test and prober operating methods, commands in use, and error situations are stored in the buffer memory  230  of  FIG. 2 . In operation S 420 , an application program of the virtual prober software that processes data as if there is the prober  120  is debugged. In operation S 430 , the application program of the debugged virtual prober software operates. In operation S 440 , it is confirmed whether the application program of the debugged virtual prober software is compatible. 
         [0048]      FIG. 6  is a flowchart illustrating an operation of determining whether there is an error in a virtual test result in operation S 320  of  FIG. 4 . In operation S 510 , commands of the prober, their processing methods, and their processed results are examined. In operation S 520 , the examined prober results are stored in the buffer memory  230  of  FIG. 2 . In operation S 530 , the compatibility of the virtual test result is confirmed. 
         [0049]    A conventional semiconductor test system requires an actual prober for driving tests. Additionally, a wafer is loaded in the actual prober. Accordingly, when conventionally developing a test or a test program, the prober needs to be set up. The semiconductor test system of the exemplary embodiment of the present invention, however, outputs a virtual test result as if the actual prober is installed without actually doing so. According to exemplary embodiments of the present invention, the inconvenience such as an actual prober setup during test or test program development and connection for the test may be resolved. 
         [0050]    The semiconductor test system of the exemplary embodiment of the present invention outputs a test result as if the actual prober is installed, without the actual prober having to be installed. According to the exemplary embodiment of the present invention, an actual prober setup during test or test program development can be eliminated. 
         [0051]    The above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other exemplary embodiments, which fall within the true spirit and scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.
A semiconductor test system capable of performing a virtual test and a semiconductor test method thereof. The semiconductor test system includes a tester providing a test signal and an emulator providing a virtual test result to the tester in response to the test signal. The emulator includes virtual prober software to obtain the virtual test result.