Abstract:
Semiconductor memory devices are provided. The semiconductor memory device includes an input/output (I/O) drive controller, a data I/O unit and a data transmitter. The input/output (I/O) drive controller generates drive control signals and an input control signal for driving first and second global I/O lines in a first test mode or a second test mode. The data I/O unit drives the first global I/O line in response to an input data when a write operation is executed in the first test mode and to drive the first and second global I/O lines in response to the drive control signals when the write operation is executed in the second test mode. The data transmitter transfers the data on the first global I/O line onto first and second local I/O lines to store the data on the first global I/O line in a memory cell array portion when the write operation is executed in the first test mode. The data transmitter also transfers the data on the first and second global I/O lines onto the first and second local I/O lines to store the data on the first and second global I/O lines in the memory cell array portion when the write operation is executed in the second test mode. Related methods are also provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    The present application is a divisional application of U.S. application Ser. No. 13/845,173, filed on Mar. 18, 2013, and claims priority under 35 U.S.C. 119(a) to Korean Application No. 10-2012-0139861, filed on Dec. 4, 2012, in the Korean Intellectual Property Office, which is incorporated herein by reference in its entirety as set forth in full. 
     
    
     BACKGROUND 
       [0002]    Various Embodiments of the present disclosure generally relate to semiconductor memory devices and methods of testing open failures thereof. 
         [0003]    Semiconductor integrated circuit devices may be fabricated using a plurality of unit processes and may be classified into good chips or failed chips through a function test. The function test may be performed to evaluate functions of peripheral circuits and memory cells constituting the semiconductor integrated circuit devices. Most of the semiconductor integrated circuit devices may tend to exhibit single bit fails more than dual bit fails. Accordingly, as the semiconductor integrated circuit devices increases a density of integration, test time of the highly integrated semiconductor integrated circuit devices have been more increased. Hence, a parallel test has been proposed to reduce the test time. The parallel test may be performed by simultaneously writing the same data into a plurality of memory cells of the semiconductor memory device and by simultaneously reading out the data stored in the plurality of memory cells. Thus, the parallel test may reduce the test time. 
         [0004]    In general, test input/output (I/O) lines in addition to global I/O lines may be required to perform the parallel test. That is, when a read operation is executed in the parallel test mode, the data stored in the memory cells may be loaded on a plurality of test I/O lines and the data levels on the plurality of test I/O lines may be detected or sensed to discriminate whether at least one of the memory cells normally operate or not. That is, when the parallel test is performed, the data stored in the memory cells may be outputted through the test I/O lines instead of the global I/O lines through which the data stored in the memory cells are outputted in a normal read mode. 
       SUMMARY 
       [0005]    According to an embodiment, a semiconductor memory device includes an input/output (I/O) drive controller, a data I/O unit and a data transmitter. The input/output (I/O) drive controller is configured to generate drive control signals and an input control signal for driving first and second global I/O lines in a first test mode or a second test mode. The data I/O unit is configured to drive the first global I/O line in response to an input data when a write operation is executed in the first test mode and to drive the first and second global I/O lines in response to the drive control signals when the write operation is executed in the second test mode. The data transmitter is configured to transfer data on the first global I/O line onto first and second local I/O lines to store the data on the first global I/O line in a memory cell array portion when the write operation is executed in the first test mode. The data transmitter is also configured to transfer data on the first and second global I/O lines onto the first and second local I/O lines to store the data on the first and second global I/O lines in the memory cell array portion when the write operation is executed in the second test mode. 
         [0006]    According to an embodiment, a semiconductor memory device includes an input/output (I/O) drive controller, a data I/O unit and a data transmitter. The input/output (I/O) drive controller is configured to generate drive control signals and an input control signal for driving first and second global I/O lines in response to a write command signal and a read command signal in a test mode. The input/output (I/O) drive controller is also configured to generate a comparison signal by comparing data on a first test line with data on a second test line in the test mode. The data I/O unit is configured to drive the first and second global I/O lines in response to the drive control signals when a write operation is executed in the test mode. The data I/O unit is also configured to output the data on the first and second global I/O lines when a read operation is executed in the test mode. The data transmitter is configured to transfer data on the first and second global I/O lines to first and second local I/O lines to store the data on the first and second global I/O lines in a memory cell array portion when the write operation is executed in the test mode. The data transmitter is also configured to transfer the data outputted from the memory cell array portion through the first and second local I/O lines to the first and second global I/O lines and the first and second test lines when the read operation is executed in the test mode. 
         [0007]    According to an embodiment, the I/O drive controller includes a selection signal generator, a drive control signal generator, a write controller and a comparison signal generator. The selection signal generator configured to generate a selection signal enabled in the test mode in response to a parallel test signal and a line test signal. The drive control signal generator configured to generate the drive control signals selectively enabled in response to the write command signal and the read command signal in the test mode. The write controller configured to generate an input control signal enabled in response to the write command signal and the read command signal when the write operation is executed in the test mode. The comparison signal generator configured to transfer the comparison signal to the first global I/O line when the read operation is executed in the test mode, wherein the drive control signals include first to fourth drive control signals. 
         [0008]    According to an embodiment, the parallel test signal is enabled to activate the test mode that stores the data generated by driving the first and second global I/O lines in the memory cell array portion and outputs the data stored in the memory cell array portion through the first and second global I/O lines to evaluate failures of the first and second global I/O lines, wherein the line test signal is enabled to activate the test mode, and the data I/O unit operates without reception of input data when the write operation is executed in the test mode. 
         [0009]    According to an embodiment, the data I/O unit drives the first and second global I/O lines to a first level in response to the drive control signals at a time that the write operation begins in the test mode. 
         [0010]    According to an embodiment, the data I/O unit drives the first and second global I/O lines to a second level in response to the drive control signals after a predetermined period elapses from the time that the write operation begins in the test mode. 
         [0011]    According to an embodiment, the data I/O unit includes a first input driver, a second input driver, a first output driver and a second output driver. The first input driver configured to transfer a first input data to the first global I/O line in response to the line test signal or to drive the first global I/O line according to the first to fourth drive control signals. The second input driver configured to transfer a second input data to the second global I/O line in response to the line test signal or to drive the second global I/O line according to the first to fourth drive control signals. The first output driver configured to generate a first output data in response to data loaded on the first global I/O line when the read operation is executed in the test mode. The second output driver configured to generate a second output data in response to data loaded on the second global I/O line when the read operation is executed in the test mode. 
         [0012]    According to an embodiment, the first input driver includes a first input unit, a first driver, a first transfer unit and a second driver. The first input unit configured to transfer the first input data to a first node in response to the line test signal. The first driver configured to drive the first node in response to the first and second drive control signals. The first transfer unit configured to transfer a signal of the first node to a second node connected to the first global I/O line in response to the input control signal. The second driver configured to drive the second node in response to the third and fourth drive control signals. 
         [0013]    According to an embodiment, the second input driver includes a second input unit, a third driver, a logic unit, a second transfer unit and a fourth driver. The second input unit configured to transfer the second input data to a third node in response to the line test signal. The third driver configured to drive the third node in response to the first and second drive control signals. The logic unit configured to generate a control signal enabled according to the input control signal and the selection signal when the write operation is executed in the test mode. The second transfer unit configured to transfer a signal of the third node to a fourth node connected to the second global I/O line in response to the control signal. The fourth driver configured to drive the fourth node in response to the third and fourth drive control signals. 
         [0014]    According to an embodiment, the data transmitter includes a transmitter, a first write driver, a selection transmitter, a second write driver, a first sense amplifier and a second sense amplifier. The transmitter configured to transfer data loaded on the first global I/O line to a first transmission line when the write operation is executed in the test mode. The first write driver configured to drive the first local I/O line in response to data on the first transmission line to store the data on the first transmission line in a first memory cell block of the memory cell array portion. The selection transmitter configured to transfer data loaded on the first global I/O line to a second transmission line in response to the selection signal or to transfer data loaded on the second global I/O line to the second transmission line when the write operation is executed in the test mode. The second write driver configured to drive the second local I/O line in response to data on the second transmission line to store the data on the second transmission line in a second memory cell block of the memory cell array portion. The first sense amplifier configured to drive the first global I/O line and the first test line in response to data on the first local I/O line when the read operation is executed in the test mode. The second sense amplifier configured to drive the second global I/O line and the second test line in response to data on the second local I/O line when the read operation is executed in the test mode. 
         [0015]    According to an embodiment, the selection transmitter includes a third driver and a fourth driver. The third driver configured to transfer data loaded on the first global I/O line to the second transmission line when the selection signal is disabled. The fourth driver configured to transfer data loaded on the second global I/O line to the second transmission line when the selection signal is enabled. 
         [0016]    According to an embodiment, the comparison signal generator includes a comparator and a transfer unit. The comparator configured to compare data loaded on the first test line with data on the second test line to generate the comparison signal. The transfer unit configured to transfer the comparison signal to the first global I/O line in response to an enablement signal enabled when the read operation is executed in the test mode. 
         [0017]    According to an embodiment, a method of testing a semiconductor memory device includes a step of writing data in a first memory cell block and a second memory cell block and a step of reading out data stored in the first and second memory cell blocks. Writing the data in the first and second memory cell blocks includes driving first and second global I/O lines in response to drive control signals generated in a test mode for evaluating failures of the first and second global I/O lines, storing the data on the first global I/O line in the first memory cell block, and storing the data on the second global I/O line in the second memory cell block. Reading out the data includes driving the first global I/O line and a first test line in response to data outputted from the first memory cell block and driving the second global I/O line and a second test line in response to data outputted from the second memory cell block. 
         [0018]    According to an embodiment, the step of writing the data further comprises the step of blocking input data to be provided to the first and second global I/O lines. 
         [0019]    According to an embodiment, wherein the step of writing the data further comprises the steps of driving the first and second global I/O lines to a first level in response to the drive control signals and driving the first and second global I/O lines to a second level in response to the drive control signals. 
         [0020]    According to an embodiment, wherein the step of reading out the data further comprises a step of outputting a comparison signal generated by comparing the data on the first test line with the data on the second test line to the first global I/O line. 
         [0021]    According to an embodiment, wherein the step of reading out the data further comprises the steps of generating a first output data in response to the data on the first global I/O line and generating a second output data in response to the data on the second global I/O line. 
         [0022]    According to an embodiment, a semiconductor integrated circuit device, comprises a first test mode configured to test a plurality of memory cells by writing and reading data through a plurality of data lines; and a second test mode configured to test the plurality of data lines by driving the plurality of data lines. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    Embodiments of the inventive concept will become more apparent in view of the attached drawings and accompanying detailed description, in which: 
           [0024]      FIG. 1  is a block diagram illustrating a configuration of a semiconductor memory device according to an embodiment; 
           [0025]      FIG. 2  is a circuit diagram illustrating a selection signal generator of a I/O drive controller included in the semiconductor memory device shown in  FIG. 1 ; 
           [0026]      FIG. 3  is a block diagram illustrating a comparison signal generator of the I/O drive controller included in the semiconductor memory device shown in  FIG. 1 ; 
           [0027]      FIG. 4  is a circuit diagram illustrating a first input driver of a data I/O unit included in the semiconductor memory device shown in  FIG. 1 ; 
           [0028]      FIG. 5  is a circuit diagram illustrating a second input driver of a data I/O unit included in the semiconductor memory device shown in  FIG. 1 ; 
           [0029]      FIG. 6  is a circuit diagram illustrating a selection transmitter of a data transmitter included in the semiconductor memory device shown in  FIG. 1 ; 
           [0030]      FIG. 7  is a timing diagram illustrating a first test mode of the semiconductor memory device according to an embodiment; and 
           [0031]      FIG. 8  is a timing diagram illustrating a second test mode of the semiconductor memory device according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0032]    Example embodiments of the inventive concept will be described hereinafter with reference to the accompanying drawings. However, the example embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the inventive concept. 
         [0033]    As illustrated in  FIG. 1 , a semiconductor integrated circuit, for example, a semiconductor memory device  100  may be configured to include an input/output (I/O) drive controller  10 , a data I/O unit  20 , a data transmitter  30  and a memory cell array portion  40 . 
         [0034]    The I/O drive controller  10  may be configured to include a selection signal generator  11 , a drive control signal generator  12 , a write controller  13  and a comparison signal generator  14 . 
         [0035]    The selection signal generator  11  may be configured to generate a selection signal SELB in response to a parallel test signal TPARA and a line test signal TLINE. The selection signal SELB is enabled during a second test mode. The semiconductor memory device  100  enters the second test mode when the parallel test signal TPARA and the line test signal TLINE are enabled. The parallel test signal TPARA may be enabled to store data loaded on a first global I/O line GIO 1  in the memory cell array portion  40 . The semiconductor memory device  10  may enter a first test by the parallel test signal TPARA. The first test compares the data stored in the memory cell array portion  40  with each other to evaluate failures of a plurality of memory cells. Further, the parallel test signal TPARA may be enabled to store data generated by driving the data loaded on the first global I/O line GIO 1  and a second global I/O line GIO 2  in the memory cell array portion  40  and to activate the second test mode that outputs the data stored in the memory cell array portion  40  through the first and second global I/O lines GIO 1  and GIO 2  to evaluate open failures of the first and second global I/O lines GIO 1  and GIO 2 . The line test signal TLINE may be enabled to activate the second test mode. That is, the semiconductor memory device  100  may operate in the first test mode when the parallel test signal TPARA is enabled and the line test signal TLINE is disabled, and the semiconductor memory device  100  may operate in the second test mode when both the parallel test signal TPARA and the line test signal TLINE are enabled. 
         [0036]    The drive control signal generator  12  may be configured to generate a plurality of drive control signals DRVCON&lt;1:4&gt; in response to the parallel test signal TPARA, the line test signal TLINE, a write command signal WT and a read command signal RD. First and second drive control signals DRVCON&lt;1:2&gt; of the plurality of drive control signals DRVCON&lt;1:4&gt; are selectively enabled when both the parallel test signal TPARA and the line test signal TLINE are enabled to activate the second test mode and when a write operation is executed in response to a write command signal WT and a read command signal RD. Third and fourth drive control signals DRVCON&lt;3:4&gt; of the plurality of drive control signals DRVCON&lt;1:4&gt; are enabled after predetermined periods from a beginning of the write operation. 
         [0037]    The write controller  13  may be configured to receive the write command signal WT and the read command signal RD and generate an input control signal DINDRV when the write operation is executed in the first or second test mode. 
         [0038]    The comparison signal generator  14  may be configured to receive an enablement signal EN to output a comparison signal COMP. The comparison signal is generated by comparing the data on a first test line TGIO 1  with the data on a second test line TGIO 2  and outputted through the first global I/O line GIO 1  when the read operation is executed in the first or second test mode. For example, if the enablement signal EN is enabled, the comparison signal COMP may be outputted onto the first global I/O line GIO 1  when the read operation is executed in the first or second test mode. 
         [0039]    The data I/O unit  20  may be configured to include a first input driver  21 , a second input driver  22 , a first output driver  23  and a second output driver  24 . 
         [0040]    The first input driver  21  may be configured to receive a first input data DIN&lt;1&gt; to drive the first global I/O line GIO 1  when the write operation is executed in a normal mode or the first test mode. Further, the first input driver  21  may configured to receive the line test signal TLINE and block an input the first input data DIN&lt;1&gt; when the write operation is executed in the second test mode. Further, the first input driver  21  may configured to receive the first and second drive control signals DRVCON&lt;1:2&gt; and drive the first global I/O line GIO 1  when the write operation is executed in the second test mode. In addition, the first input driver  21  may configured to receive the third and fourth drive control signals DRVCON&lt;3:4&gt; and drive the first global I/O line GIO 1  after a predetermined period from a beginning of the write operation. 
         [0041]    The second input driver  22  may be configured to receive a second input data DIN&lt;2&gt; to drive the second global I/O line GIO 2  when the write operation is executed in the normal mode. The second input driver  22  may not drive the second global I/O line GIO 2  when the write operation is executed in the first test mode. Further, when the write operation is executed in the second test mode, the second input driver  22  may be configured to receive the line test signal TLINE and block an inputting of the second input data DIN&lt;2&gt;. Further, the second input driver  22  may be configured to drive the second global I/O line GIO 2  in response to the first and second drive control signals DRVCON&lt;1:2&gt;. In addition, the second input driver  22  may be configured to drive the data loaded on the second global I/O line GIO 2  in response to the third and fourth drive control signals DRVCON&lt;3:4&gt; after a predetermined period from a beginning of the write operation begins, thereby driving the second global I/O line GIO 2 . 
         [0042]    The first output driver  23  may be configured to receive the data loaded on the first global I/O line GIO 1  to generate a first output data DOUT&lt;1&gt; when the read operation is executed in the normal mode, the first test mode or the second test mode. 
         [0043]    The second output driver  24  may receive the data loaded on the second global I/O line GIO 2  to generate a second output data DOUT&lt;2&gt; when the read operation is executed in the normal mode or the second test mode. The second output driver  24  may not operate when the read operation is executed in the first test mode. 
         [0044]    The data transmitter  30  may be configured to include a transmitter  31 , a first write driver  32 , a selection transmitter  33 , a second write driver  34 , a first sense amplifier  35  and a second sense amplifier  36 . 
         [0045]    The transmitter  31  may be configured to transfer the data loaded on the first global I/O line GIO 1  to a first transmission line WGIO 1  when the write operation is executed in the normal mode, the first test mode or the second test mode. 
         [0046]    The first write driver  32  may be configured to receive the data loaded on the first transmission line WGIO 1  and provide the data of the first transmission line WGIO 1  to the memory cell array portion  40  through a first local I/O line LIO 1 , to store the data on the first transmission line WGIO 1  into a first memory cell block  41  when the write operation is executed in the normal mode, the first test mode or the second test mode. 
         [0047]    The selection transmitter  33  may be configured to transfer the data loaded on the second global I/O line GIO 2  to a second transmission line WGIO 2  in response to the selection signal SELB when the write operation is executed in the normal mode or the second test mode. 
         [0048]    The second write driver  34  may be configured to receive the data loaded on the second transmission line WGIO 2  and provide the data of the second transmission line WGIO 2  to the memory cell array portion  40  through a second local I/O line LIO 2  to store the data on the second transmission line WGIO 2  into a second memory cell block  42  when the write operation is executed in the normal mode, the first test mode or the second test mode. 
         [0049]    The first sense amplifier  35  may be configured to receive the data on the first local I/O line LIO 1  and drive the first global I/O line GIO 1  when the read operation is executed in the normal mode. Further the first sense amplifier  35  may be configured to receive the data loaded on the first local I/O line LIO 1 , drive the first global I/O line GIO 1  and the first test line TGIO 1  when the read operation is executed in the first or second test mode. 
         [0050]    The second sense amplifier  36  may be configured to receive the data loaded on the second local I/O line LIO 2 , drive the second global I/O line GIO 2  when the read operation is executed in the normal mode. Further the second sense amplifier  36  may be configured to receive the data loaded on the second local I/O line LIO 2 , drive the second test line TGIO 2  when the read operation is executed in the first test mode. In addition, the second sense amplifier  36  may be configured to receive the data loaded on the second local I/O line LIO 2 , drive the second global I/O line GIO 2  and the second test line TGIO 2  when the read operation is executed in the second test mode. 
         [0051]    The memory cell array portion  40  may be configured to include a first memory cell block  41  having a plurality of memory cells and a second memory cell block  42  having a plurality of memory cells. The first memory cell block  41  may be configured to receive the data through the first local I/O line LIO 1  and the second memory cell block  42  may be configured to receive the data through the second local I/O line LIO 2 . 
         [0052]    A configuration of the selection signal generator  11  will be described more fully hereinafter with reference to  FIG. 2 . 
         [0053]    Referring to  FIG. 2 , the selection signal generator  11  may be configured to include an inverter IV 10  inversely buffering the line test signal TLINE, a NAND gate ND 10  executing a NAND operation of an output signal of the inverter IV 10  and the parallel test signal TPARA, and an inverter IV 11  inversely buffering an output signal of the NAND gate ND 10  to generate the selection signal SELB. That is, the selection signal generator  11  may receive the parallel test signal TPARA and the line test signal TLINE to generate the selection signal SELB which is enabled in the normal mode or the second test mode. 
         [0054]    A configuration of the comparison signal generator  14  will be described more fully hereinafter with reference to  FIG. 3 . 
         [0055]    Referring to  FIG. 3 , the comparison signal generator  14  may be configured to include a comparator  140  comparing the data on the first test line TGIO 1  with the data on the second test line TGIO 2  to generate the comparison signal COMP and a transfer unit  141  transferring the comparison signal COMP onto the first global I/O line GIO 1  in response to the enablement signal EN. That is, the comparison signal generator  14  may transfer the comparison signal COMP, which is generated by comparing the data on the first test line TGIO 1  with the data on the second test line TGIO 2 , to the first global I/O line GIO 1  when the read operation is executed in the first or second test mode. For example, the comparator  140  may be an exclusive NOR gate. 
         [0056]    A configuration of the first input driver  21  will be described more fully hereinafter with reference to  FIG. 4 . 
         [0057]    Referring to  FIG. 4 , the first input driver  21  may be configured to include a first input unit  210 , a first driver  211 , a first transfer unit  212  and a second driver  213 . 
         [0058]    The first input unit  210  may be configured to transfer the first input data DIN&lt;1&gt; to a first node ND 40  according to the line test signal TLINE. For example, the first input unit  210  may be a transfer gate. 
         [0059]    The first driver  211  may be configured to pull up the first node ND 40  when the first drive control signal DRVCON&lt;1&gt; is enabled and pull down the first node ND 40  when the second drive control signal DRVCON&lt;2&gt; is enabled. 
         [0060]    The first transfer unit  212  may be configured to output a signal on the first node ND 40  to a second node ND 41  electrically connected to the first global I/O line GIO 1  when the input control signal DINDRV is enabled. 
         [0061]    The second driver  213  may be configured to pull up the second node ND 41  when the fourth drive control signal DRVCON&lt;4&gt; is enabled and pull down the second node ND 41  when the third drive control signal DRVCON&lt;3&gt; is enabled. That is, the first input driver  21  may transfer the first input data DIN&lt;1&gt; to the first global I/O line GIO 1  when the write operation is executed in the normal mode or the first test mode and may drive the first global I/O line GIO 1  without reception of the first input data DIN&lt;1&gt; when the write operation is executed in the second test mode. 
         [0062]    A configuration of the second input driver  22  will be described more fully hereinafter with reference to  FIG. 5 . 
         [0063]    Referring to  FIG. 5 , the second input driver  22  may be configured to include a second input unit  220 , a third driver  221 , a logic unit  222 , a second transfer unit  223 , and a fourth driver  224   
         [0064]    The second input unit  2210  may be transferred the second input data DIN&lt;2&gt; to a third node ND 42  according to the line test signal TLINE. 
         [0065]    The third driver  221  may be configured to pull up the third node ND 42  when the first drive control signal DRVCON&lt;1&gt; is enabled and pull down the third node ND 42  when the second drive control signal DRVCON&lt;2&gt; is enabled. 
         [0066]    The logic unit  222  may be configured to generate a control signal CONB in response to the input control signal DINDRV and the selection signal SELB. For example, the logic unit  222  may include a inverter for inverting the selection signal SELB and a NAND gate for NAND operating the inversed selection signal SELB and the input control signal DINDRV. 
         [0067]    The second transfer unit  223  may be configured to output a signal on the third node ND 42  to a fourth node ND 43  electrically connected to the second global I/O line GIO 2  when the control signal CONB is enabled. 
         [0068]    The fourth driver  224  may be configured to pull up the fourth node ND 43  when the fourth drive control signal DRVCON&lt;4&gt; is enabled and pull down the fourth node ND 43  when the third drive control signal DRVCON&lt;3&gt; is enabled. That is, the second input driver  22  may transfer the second input data DIN&lt;2&gt; to the second global I/O line GIO 2  when the write operation is executed in the normal mode and may not transfer the second input data DIN&lt;2&gt; to the second global I/O line GIO 2  when the write operation is executed in the first test mode. Further, the second input driver  22  may drive the second global I/O line GIO 2  without reception of the second input data DIN&lt;2&gt; when the write operation is executed in the second test mode. 
         [0069]    A configuration of the selection transmitter  33  will be described more fully hereinafter with reference to  FIG. 6 . 
         [0070]    Referring to  FIG. 6 , the selection transmitter  33  may be configured to include a third driver  330  and the fourth driver  331 . The third driver  330  may be configured to operate when the selection signal SELB is disabled to transfer the data on the first global I/O line GIO 1  to the second transmission line WGIO 2 . The fourth driver  331  may be configured to operate when the selection signal SELB is enabled to transfer the data on the second global I/O line GIO 2  to the second transmission line WGIO 2 . That is, the selection transmitter  33  may transfer the data on the first global I/O line GIO 1  to the second transmission line WGIO 2  when the write operation is executed in the first test mode. In addition, the selection transmitter  33  may transfer the data on the second global I/O line GIO 2  to the second transmission line WGIO 2  when the write operation is executed in the normal mode or the second test mode. 
         [0071]    An operation of the semiconductor memory device in the first test mode which is capable of sorting failed memory cells will be described in conjunction with an example that both the first and second input data DIN&lt;1:2&gt; have a logic “high” level with reference to  FIG. 7 . 
         [0072]    Referring to  FIG. 7 , at a time T 1 , the selection signal generator  11  of the I/O drive controller  10  may receive the parallel test signal TPARA enabled to have a logic “high” level and the line test signal TLINE disabled to have a logic “low” level, to generate the selection signal SELB disabled to have a logic “high” level in order to enter the first test mode. 
         [0073]    Subsequently, if the write operation is executed at a time T 2 , the drive control signal generator  12  of the I/O drive controller  10  may receive the write command signal WT in the first test mode, thus stop to generate the first to fourth drive control signals DRVCON&lt;1:4&gt;. The write controller  13  may receive the write command signal WT in the first test mode to generate the input control signal DINDRV which is enabled to have a logic “high” level. 
         [0074]    The first input driver  21  of the data I/O unit  20  may provide the first input data DIN&lt;1&gt; to the first global I/O line GIO 1  in response to the line test signal TLINE having a logic “low” level. The second input driver  22  of the data I/O unit  20  may provide the second input data DIN&lt;2&gt; to the second global I/O line GIO 2  in response to the line test signal TLINE having a logic “low” level. 
         [0075]    The transmitter  31  of the data transmitter  30  may receive the data of a logic “high” level on the first global I/O line GIO 1  and may transfer the data of a logic “high” level on the first global I/O line GIO 1  to the first transmission line WGIO 1 . The first write driver  32  may drive the first local I/O line LIO 1  in response to the data loaded on the first transmission line WGIO 1  to store the data on the first transmission line WGIO 1  into the first memory cell block  41 . The selection transmitter  33  may transfer the data loaded on the first global I/O line GIO 1  to the second transmission line WGIO 2  in response to the selection signal SELB having a logic “high” level. In such a case, the selection transmitter  33  may not receive the data on the second global I/O line GIO 2  because the selection signal SELB has a logic “high” level. 
         [0076]    The second write driver  34  may drive the second local I/O line LIO 2  in response to the data loaded on the second transmission line WGIO 2  to store the data on the second transmission line WGIO 2  into the second memory cell block  42 . 
         [0077]    Next, if the read operation is executed at a time T 3 , the first sense amplifier  35  of the data transmitter  30  may receive the data having a logic “high” level outputted from the first memory cell block  41  through the first local I/O line LIO 1  to drive the first test line TGIO 1  to a logic “high” level. The second sense amplifier  36  of the data transmitter  30  may receive the data having a logic “high” level outputted from the second memory cell block  42  through the second local I/O line LIO 2  to drive the second test line TGIO 2  to a logic “high” level. The comparator  140  of the comparison signal generator  14  may compare the data on the first test line TGIO 1  with the data on the second test line TGIO 2  to generate the comparison signal COMP having a logic “high” level. 
         [0078]    Subsequently, if the enablement signal EN is enabled at a time T 4 , the transfer unit  141  may transmit the comparison signal COMP having a logic “high” level to the first global I/O line GIO 1 . The first output driver  23  of the data I/O unit  20  may receive the signal having a logic “high” level on the first global I/O line GIO 1  to generate the first output data DOUT&lt;1&gt; having a logic “high” level. Since the first output data DOUT&lt;1&gt; has a logic “high” level and the first and second input data DIN&lt;1:2&gt; have a logic “high” level, no failed memory cells may exist in the first and second memory cell blocks  41  and  42 . 
         [0079]    As described above, the first test mode may be used to evaluate whether failed memory cells exist in the memory cell array portion  40 . 
         [0080]    Now, an operation of the semiconductor memory device in the second test mode which is capable of evaluating open failures of the global I/O lines will be described in conjunction with an example that the first global I/O line GIO 1  has an open failure and has a logic “high” level with reference to  FIG. 8 . 
         [0081]    Referring to  FIG. 8 , at a time T 10 , the selection signal generator  11  of the I/O drive controller  10  may generate the selection signal SELB enabled to have a logic “low” level in order to enter the second test mode in response to the parallel test signal TPARA and the line test signal TLINE which are enabled to have a logic “high” level. 
         [0082]    Subsequently, if the write operation is executed at a time T 11 , the drive control signal generator  12  of the I/O drive controller  10  may receive the write command signal WT in the second test mode to generate the first drive control signal DRVCON&lt;1&gt; which is enabled to have a logic “high” level. The write controller  13  may receive the write command signal WT in the second test mode to generate the input control signal DINDRV which is enabled to have a logic “high” level. 
         [0083]    The first input driver  21  of the data I/O unit  20  may pull up the first node ND 40  in response to the first drive control signal DRVCON&lt;1&gt; having a logic “high” level to drive the first global I/O line GIO 1  to a logic “high” level. The second input driver  22  of the data I/O unit  20  may pull up the third node ND 42  in response to the first drive control signal DRVCON&lt;1&gt; having a logic “high” level to drive the second global I/O line GIO 2  to a logic “high” level. 
         [0084]    The transmitter  31  of the data transmitter  30  may transfer the data of a logic “high” level on the first global I/O line GIO 1  to the first transmission line WGIO 1 . The first write driver  32  may drive the first local I/O line LIO 1  in response to the data on the first transmission line WGIO 1  to store the data on the first transmission line WGIO 1  into the first memory cell block  41 . The selection transmitter  33  may transfer the data of a logic “high” level on the second global I/O line GIO 2  to the second transmission line WGIO 2  in response to the selection signal SELB having a logic “low” level. In such a case, the selection transmitter  33  may not receive the data on the first global I/O line GIO 1  because the selection signal SELB has a logic “low” level. The second write driver  34  may drive the second local I/O line LIO 2  in response to the data loaded on the second transmission line WGIO 2  to store the data on the second transmission line WGIO 2  into the second memory cell block  42 . 
         [0085]    Next, the drive control signal generator  12  of the I/O drive controller  10  may generate the third drive control signal DRVCON&lt;3&gt; which is enabled to have a logic “high” level at a time T 12  that a predetermined period elapses from the time T 11  that the write operation begins. The first input driver  21  of the data I/O unit  20  may pull down the second node ND 41  in response to the third drive control signal DRVCON&lt;3&gt; having a logic “high” level to drive the first global I/O line GIO 1  to a logic “low” level. The second input driver  22  of the data I/O unit  20  may pull down the fourth node ND 43  in response to the third drive control signal DRVCON&lt;3&gt; having a logic “high” level to drive the second global I/O line GIO 2  to a logic “low” level. However, when the second global I/O line GIO 2  has an open failure, the second global I/O line GIO 2  may not be driven to a logic “low” level even though the second input driver  22  pulls down the fourth node ND 43 . 
         [0086]    If the read operation is executed at a time T 13 , the first sense amplifier  35  of the data transmitter  30  may receive the data having a logic “high” level outputted from the first memory cell block  41  through the first local I/O line LIO 1  to drive the first test line TGIO 1  and the first global I/O line GIO 1  to a logic “high” level. The second sense amplifier  36  of the data transmitter  30  may receive the data having a logic “high” level outputted from the second memory cell block  42  through the second local I/O line LIO 2  to drive the second test line TGIO 2  and the second global I/O line GIO 2  to a logic “high” level. The comparator  140  of the comparison signal generator  14  may compare the data on the first test line TGIO 1  with the data loaded on the second test line TGIO 2  to generate the comparison signal COMP having a logic “high” level. 
         [0087]    Subsequently, if the enablement signal EN is enabled at a time T 14 , the transfer unit  141  of the comparison signal generator  14  may transmit the comparison signal COMP having a logic “high” level to the first global I/O line GIO 1 . The first output driver  23  of the data I/O unit  20  may generate the first output data DOUT&lt;1&gt; having a logic “high” level in response to the signal having a logic “high” level on the first global I/O line GIO 1 . The second output driver  24  may receive to generate the second output data DOUT&lt;2&gt; having a logic “high” level, in response to the signal on the second global I/O line GIO 2 . The levels of the first and second output data DOUT&lt;1:2&gt; may be sensed or detected to evaluate whether an open failure exists in the global I/O lines GIO 1  and GIO 2 . However, since the second global I/O line GIO 2  has a logic “high” level due to an open failure, the second output data DOUT&lt;2&gt; may be generated to have a logic “high” level. Thus, the second global I/O line GIO 2  may be evaluated as being normal without any open failures. Accordingly, the first and second global I/O lines GIO 1  and GIO 2  may be driven to a logic “low” level to execute the write operation and the read operation again. 
         [0088]    Hereinafter, an operation of driving the first and second global I/O lines GIO 1  and GIO 2  to a logic “low” level will be described. 
         [0089]    First, if the write operation is executed at a time T 15 , the drive control signal generator  12  of the I/O drive controller  10  may receive the write command signal WT in the second test mode to generate the second drive control signal DRVCON&lt;2&gt; which is enabled to have a logic “high” level and the write controller  13  may receive the write command signal WT in the second test mode to generate the input control signal DINDRV which is enabled to have a logic “high” level. 
         [0090]    The first input driver  21  of the data I/O unit  20  may pull down the first node ND 40  in response to the second drive control signal DRVCON&lt;2&gt; having a logic “high” level to drive the first global I/O line GIO 1  to a logic “low” level. The second input driver  22  of the data I/O unit  20  may pull down the third node ND 42  in response to the second drive control signal DRVCON&lt;2&gt; having a logic “high” level to drive the second global I/O line GIO 2  to a logic “low” level. However, since the second global I/O line GIO 2  has an open failure, the second global I/O line GIO 2  may not be driven to a logic “low” level even though the second input driver  22  pulls down the third node ND 42 . 
         [0091]    The transmitter  31  of the data transmitter  30  may transfer the data of a logic “low” level on the first global I/O line GIO 1  to the first transmission line WGIO 1 . The first write driver  32  may drive the first local I/O line LIO 1  in response to the data loaded on the first transmission line WGIO 1  to store the data on the first transmission line WGIO 1  into the first memory cell block  41 . The selection transmitter  33  may transfer the data of a logic “high” level on the second global I/O line GIO 2  to the second transmission line WGIO 2  in response to the selection signal SELB having a logic “low” level. In such a case, the selection transmitter  33  may not receive the data on the first global I/O line GIO 1  because the selection signal SELB has a logic “low” level. The second write driver  34  may drive the second local I/O line LIO 2  in response to the data on the second transmission line WGIO 2  to store the data on the second transmission line WGIO 2  into the second memory cell block  42 . 
         [0092]    Next, the drive control signal generator  12  of the I/O drive controller  10  may generate the fourth drive control signal DRVCON&lt;4&gt; which is enabled to have a logic “high” level at a time T 16  that a predetermined period elapses from the time T 15  that the write operation begins. The first input driver  21  of the data I/O unit  20  may pull up the second node ND 41  in response to the fourth drive control signal DRVCON&lt;4&gt; having a logic “high” level to drive the first global I/O line GIO 1  to a logic “high” level. The second input driver  22  of the data I/O unit  20  may pull up the fourth node ND 43  in response to the fourth drive control signal DRVCON&lt;4&gt; having a logic “high” level to drive the second global I/O line GIO 2  to a logic “high” level. 
         [0093]    If the read operation is executed at a time T 17 , the first sense amplifier  35  of the data transmitter  30  may receive the data having a logic “low” level outputted from the first memory cell block  41  through the first local I/O line LIO 1  to drive the first test line TGIO 1  and the first global I/O line GIO 1  to a logic “low” level. The second sense amplifier  36  of the data transmitter  30  may receive the data having a logic “high” level outputted from the second memory cell block  42  through the second local I/O line LIO 2  to drive the second test line TGIO 2  and the second global I/O line GIO 2  to a logic “high” level. The comparator  140  of the comparison signal generator  14  may compare the data on the first test line TGIO 1  with the data on the second test line TGIO 2  to generate the comparison signal COMP having a logic “low” level. 
         [0094]    Subsequently, if the enablement signal EN is enabled at a time T 18 , the transfer unit  141  of the comparison signal generator  14  may transmit the comparison signal COMP having a logic “low” level to the first global I/O line GIO 1 . The first output driver  23  of the data I/O unit  20  may generate the first output data DOUT&lt;1&gt; having a logic “low” level in response to the signal having a logic “low” level on the first global I/O line GIO 1 . The second output driver  24  may generate the second output data DOUT&lt;2&gt; having a logic “high” level in response to the signal on the second global I/O line GIO 2  to. The levels of the first and second output data DOUT&lt;1:2&gt; may be sensed or detected to evaluate whether an open failure exists in the global I/O lines GIO 1  and GIO 2 . Since the second global I/O line GIO 2  is not driven to a logic “low” level due to an open failure during the write operation, the second output data DOUT&lt;2&gt; may be generated to have a logic “high” level during the read operation. Thus, the second global I/O line GIO 2  may be evaluated as being abnormal with an open failure. 
         [0095]    As described above, the semiconductor memory device according to the embodiments may be configured to find out open failures of the global I/O lines in the second test mode. 
         [0096]    The example embodiments of the inventive concept have been disclosed above for illustrative purposes. Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the inventive concept as disclosed in the accompanying claims.