Patent Publication Number: US-8981808-B2

Title: Semiconductor device and test method thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a semiconductor device and a test method thereof, and more particularly relates to a semiconductor device that includes a plurality of core chips and an interface chip for controlling the core chips and a test method thereof. 
     2. Description of the Related Art 
     A memory capacity that is required in a semiconductor memory device such as a DRAM (Dynamic Random Access Memory) are increasing every year. Increasing a memory capacity of a memory chip may use finer processing being performed on the memory chip. Therefore, in recent years, a memory device that is called a multi-chip package where plural memory chips are laminated is suggested to satisfy the required memory capacity (see Japanese Patent Application Laid-Open (JP-A) No. 2002-305283). However, since the memory chip used in the multi-chip package is a common memory chip capable of operating even though the memory chip is a single chip, a so-called front end unit that performs a function of an interface with an external device is included in each memory chip. For this reason, it is difficult to greatly increase a memory capacity for each chip. 
     In addition, a circuit that constitutes the front end unit is manufactured at the same time as a back end unit including a memory core, regardless of the circuit being a circuit of a logic system. It may be difficult to speed up the front end unit. 
     As a method to resolve the above problem, a method that detaches the front end unit from each memory chips and integrate them in one interface chip and laminates these chips, thereby constituting one semiconductor memory device, is suggested (see JP-A No. 2007-157266 or JP-A No. 2006-313607). According to this method, with respect to memory chips (Hereafter, a memory chip whose front end unit was detached is called ‘a core chip’.), it becomes possible to increase a memory capacity for each chip because an occupied area assignable for the memory core increases. Meanwhile, with respect to an interface chip that is integrated with the front end unit, it becomes possible to form its circuit with a high-speed transistor because the interface chip can be manufactured using a process different from that of the memory core. In addition, since the plural core chips can be allocated to one interface chip, it becomes possible to provide a semiconductor memory device that has a large memory capacity and a high operation speed as a whole. 
     As a test method of a semiconductor device, a “parallel test” has been known, in which a plurality of bit data (bit data to be stored in more memory cells than memory cells simultaneously activated at the time of normal operation) are output at the same time, and a result of comparing their outputs is output to outside as a test result (see Japanese Patent Application Laid-open No. H11-339499). A test time can be shortened by performing the parallel test. 
     However, in the above conventional multichip package or a semiconductor device including a plurality of core chips and an interface chip, there has been a problem that it takes a long time to perform a test. This problem is explained in detail below with the latter case as an example. 
     In the semiconductor device including a plurality of core chips and an interface chip, a data terminal of each of the core chips is connected to an external data terminal provided on the interface chip via a through silicon via that is commonly connected to the core chips and the interface chip. Because the test result is also output as a type of data, it is output to outside via the through silicon via. Therefore, the test results cannot be output from the core chips in a simultaneous manner, requiring them to be output in a sequential manner, thus taking a long time to perform the test. 
     Therefore, it has been desired to shorten the time required for a test of the above conventional multichip package or the semiconductor device including a plurality of core chips and an interface chip. 
     SUMMARY 
     In one embodiment, there is provided a semiconductor device comprising: a plurality of memory chips laminated to each other; and a plurality of current paths penetrating through the memory chips, wherein each of the memory chips includes a memory cell array and a first test circuit that outputs a layer test result signal generated based on test data read from a corresponding one of the memory cell array to a different one of the current paths. 
     In another embodiment, there is provided a test method of a semiconductor device comprising: providing the semiconductor device including a plurality of memory chips laminated to each other, each including a memory cell array, and a plurality of current paths penetrating through the memory chips; writing test data into each of the memory cell arrays; reading the test data from each of the memory cell arrays; generating layer test result signals in each of the memory ships based on the test data read from the memory cell arrays; and outputting each of the layer test result signals to a different one of the current paths for each of the memory chips. 
     According to the present invention, because test data are output from different current paths that vary from one memory chip to another, it is possible to output the test data of a plurality of memory chips at the same time. Therefore, it is possible to shorten the time required for the test of the above conventional multichip package or the semiconductor device including a plurality of core chips and an interface chip. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above features and advantages of the present invention will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a schematic cross-sectional view provided to explain the structure of a semiconductor memory device  10  according to the preferred embodiment of the present invention; 
         FIGS. 2A to 2C  are diagram showing the various types of TSV provided in a core chip; 
         FIG. 3  is a cross-sectional view illustrating the structure of the through silicon via of the type shown in  FIG. 2A ; 
         FIG. 4  is a block diagram illustrating the circuit configuration of the semiconductor memory device according the first embodiment of the present invention; 
         FIG. 5  is a schematic cross section of a circuit including the through silicon via group (a spirally-connected through silicon via group) connecting the test circuits provided in the core chips and the test circuit provided in the interface chip; 
         FIG. 6  is a block diagram showing functional blocks of the test circuits provided in the core chips; 
         FIG. 7  is a block diagram showing an example of the comparison circuit units provided in the core chips; 
         FIG. 8  is a block diagram showing an example of the test output control units provided in the core chips; 
         FIG. 9  is a schematic block diagram showing another example of the test output control units provided in the core chips; 
         FIG. 10  is a schematic block diagram showing functional blocks of the test circuit provided in the interface chip; 
         FIG. 11  is a schematic block diagram showing an example of the test output control unit provided in the interface chip; 
         FIG. 12  is a flowchart showing a process flow of the post-assembly test; and 
         FIG. 13  is a block diagram showing the configuration of a data processing system using the semiconductor memory device according to the preferred embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Preferred embodiments of the present invention will be explained below in detail with reference to the accompanying drawings. 
       FIG. 1  is a schematic cross-sectional view provided to explain the structure of a semiconductor memory device  10  according to the preferred embodiment of the present invention. 
     As shown in  FIG. 1 , the semiconductor memory device  10  according to this embodiment has the structure where 8 core chips CC 0  to CC 7  that have the same function and structure and are manufactured using the same manufacture mask, an interface chip IF that is manufactured using a manufacture mask different from that of the core chips and an interposer IP are laminated. The core chips CC 0  to CC 7  and the interface chip IF are semiconductor chips using a silicon substrate and are electrically connected to adjacent chips in a vertical direction through plural through silicon vias TSV penetrating the silicon substrate. Meanwhile, the interposer IP is a circuit board that is made of a resin, and plural external terminals (solder balls) SB are formed in a back surface IPb of the interposer IP. 
     Each of the core chips CC 0  to CC 7  is a semiconductor chip which consists of circuit blocks other than a so-called front end unit (front end function) performing a function of an interface with an external device through an external terminal among circuit blocks included in a 1 Gb DDR3 (Double Data Rate 3)-type SDRAM (Synchronous Dynamic Random Access Memory). The SDRAM is a well-known and common memory chip that includes both of the front end unit and a so-called back end unit having a plural memory cells and accessing to the memory cells. The SDRAM operates even as a single chip and is capable to communicate directly with a memory controller. That is, each of the core chips CC 0  to CC 7  is a semiconductor chip where only the circuit blocks belonging to the back end unit are integrated in principle. As the circuit blocks that are included in the front end unit, a parallel-serial converting circuit (data latch circuit) that performs parallel/serial conversion on input/output data between a memory cell array and a data input/output terminal and a DLL (Delay Locked Loop) circuit that controls input/output timing of data are exemplified, which will be described in detail below. The interface chip IF is a semiconductor chip in which only the front end unit is integrated. Accordingly, an operation frequency of the interface chip is higher than an operation frequency of the core chip. Since the circuits that belong to the front end unit are not included in the core chips CC 0  to CC 7 , the core chips CC 0  to CC 7  cannot be operated as the single chips, except for when the core chips are operated in a wafer state for a test operation in the course of manufacturing the core chips. The interface chip IF is needed to operate the core chips CC 0  to CC 7 . Accordingly, the memory integration of the core chips is denser than the memory integration of a general single chip. In the semiconductor memory device  10  according to this embodiment, the interface chip has a front end function for communicating with the external device at a first operation frequency, and the plural core chips have a back end function for communicating with only the interface chip at a second operation frequency lower than the first operation frequency. Accordingly, each of the plural core chips includes a memory cell array that stores plural information, and a bit number of plural read data for each I/O (DQ) that are supplied from the plural core chips to the interface chip in parallel is plural and associated with a one-time read command provided from the interface chip to the core chips. In this case, the plural bit number corresponds to a prefetch data number to be well-known. 
     The interface chip IF functions as a common front end unit for the eight core chips CC 0  to CC 7 . Accordingly, all external accesses are performed through the interface chip IF and inputs/outputs of data are also performed through the interface chip IF. In this embodiment, the interface chip IF is disposed between the interposer IP and the core chips CC 0  to CC 7 . However, the position of the interface chip IF is not restricted in particular, and the interface chip IF may be disposed on the core chips CC 0  to CC 7  and may be disposed on the back surface IPb of the interposer IP. When the interface chip IF is disposed on the core chips CC 0  to CC 7  in a face-down manner or is disposed on the back surface IPb of the interposer IP in a face-up manner, the through silicon via TSV does not need to be provided in the interface chip IF. The interface chip IF may be disposed to be interposed between the two interposers IP. 
     The interposer IP functions as a rewiring substrate to increase an electrode pitch and secures mechanical strength of the semiconductor memory device  10 . That is, an electrode  101  that is formed on a top surface IPa of the interposer IP is drawn to the back surface IPb via a through-hole electrode  102  and the pitch of the external terminals SB is enlarged by the rewiring layer  103  provided on the back surface IPb. In  FIG. 1 , only the two external terminals SB are shown. In actuality, however, three or more external terminals are provided. The layout of the external terminals SB is the same as that of the DDR3-type SDRAM that is determined by the regulation. Accordingly, the semiconductor memory device can be treated as one DDR3-type SDRAM from the external controller. 
     As shown in  FIG. 1 , a top surface of the uppermost core chip CC 0  is covered by an NCF (Non-Conductive Film)  104  and a lead frame  105 . Gaps between the core chips CC 0  to CC 7  and the interface chip IF are filled with an underfill  106  and surrounding portions of the gaps are covered by a sealing resin  107 . Thereby, the individual chips are physically protected. 
     When most of the through silicon vias TSV provided in the core chips CC 0  to CC 7  are two-dimensionally viewed from a lamination direction, that is, viewed from an arrow A shown in  FIG. 1 , the through silicon vias TSV are short-circuited from the through silicon vias TSV of other layers provided at the same position. That is, as shown in  FIG. 2A , the vertically disposed through silicon vias TSV 1  that are provided at the same position in plan view are short-circuited, and one wiring line (a current path) is configured by the through silicon vias TSV 1 . This connecting configuration of the through silicon vias TSV is called ‘straight connection’. The through silicon vias TSV 1  that are provided in the core chips CC 0  to CC 7  are connected to internal circuits  4  in the core chips, respectively. Accordingly, input signals (command signal, address signal, etc.) that are supplied from the interface chip IF to the through silicon vias TSV 1  shown in  FIG. 2A  are commonly input to the internal circuits  4  of the core chips CC 0  to CC 7 . Output signals (data etc.) that are supplied from the core chips CC 0  to CC 7  to the TSV 1  are wired-ORed and input to the interface chip IF. 
     Meanwhile, as shown in  FIG. 2B , the a part of through silicon vias TSV are not directly connected to the through silicon via TSV 2  of other layers provided at the same position in plain view but are connected to the through silicon via TSV 2  of other layers through the internal circuits  5  provided in the core chips CC 0  to CC 7 . That is, the internal circuits that are provided in the core chips CC 0  to CC 7  are cascade-connected through the through silicon vias TSV 2 . This kind of through silicon vias TSV 2  is used to sequentially transmit predetermined information to the internal circuits  5  provided in the core chips CC 0  to CC 7 . As this information, layer address information to be described below is exemplified. 
     Another through silicon via TSV group is short-circuited from the through silicon via TSVs of other layer provided at the different position in plan view, as shown in  FIG. 2C . With respect to this kind of through silicon via TSV group  3 , internal circuits  6  of the core chips CC 0  to CC 7  are connected to the TSV 3   a  provided at the predetermined position P in plan view. This connecting configuration of the through silicon vias TSV is called ‘spiral connection’ and described in detail later. The spiral connection results in that internal circuits  6  provided in each of the core chips is connected to the interface chip IF via different current paths from each other. Thereby, information can be selectively input to the core chips from the interface chip IF. As this information, defective chip information, test layer activation signals TLSE, and layer test result signals output from a test circuit  67  is exemplified. Details of these examples are described later. 
     As such, as types of the through silicon vias TSV provided in the core chips CC 0  to CC 7 , three types (TSV 1  to TSV 3 ) shown in  FIGS. 2A to 2C  exist. As described above, most of the through silicon vias TSV are of a type shown in  FIG. 2A , and an address signal, a command signal, and a clock signal are supplied from the interface chip IF to the core chips CC 0  to CC 7 , through the through silicon vias TSV 1  of the type shown in  FIG. 2A . Read data and write data are also input to and output from the interface chip IF through the through silicon vias TSV 1  of the type shown in  FIG. 2A . Meanwhile, the through silicon vias TSV 2  and through silicon vias TSV 3  of the types shown in  FIGS. 2B and 2C  are used to provide individual information to the core chips CC 0  to CC 7  having the same structure. 
       FIG. 3  is a cross-sectional view illustrating the structure of the through silicon via TSV 1  of the type shown in  FIG. 2A . 
     As shown in  FIG. 3 , the through silicon via TSV 1  is provided to penetrate a silicon substrate  90  and an interlayer insulating film  91  provided on a surface of the silicon substrate  90 . Around the through silicon via TSV 1 , an insulating ring  92  is provided. Thereby, the through silicon via TSV 1  and a transistor region are insulated from each other. In an example shown in  FIG. 3 , the insulating ring  92  is provided double. Thereby, capacitance between the through silicon via TSV 1  and the silicon substrate  90  is reduced. 
     An end  93  of the through silicon via TSV 1  at the back surface of the silicon substrate  90  is covered by a back surface bump  94 . The back surface bump  94  is an electrode that contacts a surface bump  95  provided in a core chip of a lower layer. The surface bump  95  is connected to an end  96  of the through silicon via TSV 1 , through plural pads P 0  to P 3  provided in wiring layers L 0  to L 3  and plural through-hole electrodes TH 1  to TH 3  connecting the pads to each other. Thereby, the surface bump  95  and the back surface bump  94  that are provided at the same position in plan view are short-circuited. Connection with internal circuits (not shown in the drawings) is performed through internal wiring lines (not shown in the drawings) drawn from the pads P 0  to P 3  provided in the wiring layers L 0  to L 3 . 
       FIG. 4  is a block diagram illustrating the circuit configuration of the semiconductor memory device  10 . 
     As shown in  FIG. 4 , the external terminals that are provided in the interposer IP include clock terminals  11   a  and  11   b , an clock enable terminal  11   c , command terminals  12   a  to  12   e , an address terminal  13 , a data input/output terminal  14 , data strobe terminals  15   a  and  15   b , a calibration terminal  16 , and power supply terminals  17   a  and  17   b . All of the external terminals are connected to the interface chip IF and are not directly connected to the core chips CC 0  to CC 7 , except for the power supply terminals  17   a  and  17   b.    
     First, a connection relationship between the external terminals and the interface chip IF performing the front end function and the circuit configuration of the interface chip IF will be described. 
     The clock terminals  11   a  and  11   b  are supplied with external clock signals CK and /CK, respectively, and the clock enable terminal  11   c  is supplied with a clock enable signal CKE. The external clock signals CK and /CK and the clock enable signal CKE are supplied to a clock generating circuit  21  provided in the interface chip IF. A signal where “/” is added to a head of a signal name in this specification indicates an inversion signal of a corresponding signal or a low-active signal. Accordingly, the external clock signals CK and /CK are complementary signals. The clock generating circuit  21  generates an internal clock signal ICLK, and the generated internal clock signal ICLK is supplied to various circuit blocks in the interface chip IF and is commonly supplied to the core chips CC 0  to CC 7  through the through silicon vias TSV. 
     A DLL circuit  22  is included in the interface chip IF and an input/output clock signal LCLK is generated by the DLL circuit  22 . The input/output clock signal LCLK is supplied to an input/output buffer circuit  23  included in the interface chip IF. A DLL function is used to control the front end unit by using the signal LCLK synchronized with a signal of the external device, when the semiconductor memory device  10  communicates with the external device. Accordingly, DLL function is not needed for the core chips CC 0  to CC 7  as the back end. 
     The command terminals  12   a  to  12   e  are supplied with a row-address strobe signal /RAS, a column address strobe signal /CAS, a write enable signal /WE, a chip select signal /CS, and an on-die termination signal ODT. These command signals are supplied to a command input buffer  31  that is provided in the interface chip IF. The command signals supplied to the command input buffer  31  are further supplied to a command decoder/control logic circuit  32 . The command decoder/control logic circuit  32  is a circuit that holds, decodes, and counts the command signals in synchronization with the internal clock ICLK and generates various internal commands ICMD. The generated internal command ICMD is supplied to the various circuit blocks in the interface chip IF and is commonly supplied to the core chips CC 0  to CC 7  through the through silicon vias TSV. 
     The address terminal  13  is a terminal to which address signals A 0  to A 15  and BA 0  to BA 2  are supplied, and the supplied address signals A 0  to A 15  and BA 0  to BA 2  are supplied to an address input buffer  41  provided in the interface chip IF. An output of the address input buffer  41  is commonly supplied to the core chips CC 0  to CC 7  through the through silicon vias TSV. The address signals A 0  to A 15  are supplied to a mode register  42  provided in the interface chip IF, when the semiconductor memory device  10  enters a mode register set. The address signals BA 0  to BA 2  (bank addresses) are decoded by an address decoder (not shown in the drawings) provided in the interface chip IF, and a bank selection signal B that is obtained by the decoding is supplied to a data latch circuit  25 . This is because bank selection of the write data is performed in the interface chip IF. 
     The data input/output terminal  14  is used to input/output read data or write data DQ 0  to DQ 15 . The data strobe terminals  15   a  and  15   b  are terminals that are used to input/output strobe signals DQS and /DQS. The data input/output terminal  14  and the data strobe terminals  15   a  and  15   b  are connected to the input/output buffer circuit  23  provided in the interface chip IF. The input/output buffer circuit  23  includes an input buffer IB and an output buffer OB, and inputs/outputs the read data or the write data DQ 0  to DQ 15  and the strobe signals DQS and /DQS in synchronization with the input/output clock signal LCLK supplied from the DLL circuit  22 . If an internal on-die termination signal IODT is supplied from the command decoder/control logic circuit  32 , the input/output buffer circuit  23  causes the output buffer OB to function as a termination resistor. An impedance code DRZQ is supplied from the calibration circuit  24  to the input/output buffer circuit  23 . Thereby, impedance of the output buffer OB is designated. The input/output buffer circuit  23  includes a well-known FIFO circuit. 
     The calibration circuit  24  includes a replica buffer RB that has the same circuit configuration as the output buffer OB. If the calibration signal ZQ is supplied from the command decoder/control logic circuit  32 , the calibration circuit  24  refers to a resistance value of an external resistor (not shown in the drawings) connected to the calibration terminal  16  and performs a calibration operation. The calibration operation is an operation for matching the impedance of the replica buffer RB with the resistance value of the external resistor, and the obtained impedance code DRZQ is supplied to the input/output buffer circuit  23 . Thereby, the impedance of the output buffer OB is adjusted to a desired value. 
     The input/output buffer circuit  23  is connected to a data latch circuit  25 . The data latch circuit  25  includes a FIFO circuit (not shown in the drawings) that realizes a FIFO function which operates by latency control realizing the well-known DDR function and a multiplexer MUX (not shown in the drawings). The input/output buffer circuit  23  converts parallel read data, which is supplied from the core chips CC 0  to CC 7 , into serial read data, and converts serial write data, which is supplied from the input/output buffer, into parallel write data. Accordingly, the data latch circuit  25  and the input/output buffer circuit  23  are connected in serial and the data latch circuit  25  and the core chips CC 0  to CC 7  are connected in parallel. In this embodiment, each of the core chips CC 0  to CC 7  is the back end unit of the DDR3-type SDRAM and a prefetch number is 8 bits. The data latch circuit  25  and each banks of the core chips CC 0  to CC 7  are connected respectively, and the number of banks that are included in each of the core chips CC 0  to CC 7  is 8. Accordingly, connection of the data latch circuit  25  and the core chips CC 0  to CC 7  becomes 64 bits (8 bits×8 banks) for each DQ. 
     Parallel data, not converted into serial data, is basically transferred between the data latch circuit  25  and the core chips CC 0  to CC 7 . That is, in a common SDRAM (in the SDRAM, a front end unit and a back end unit are constructed in one chip), between the outside of the chip and the SDRAM, data is input/output in serial (that is, the number of data input/output terminals is one for each DQ). However, in the core chips CC 0  to CC 7 , an input/output of data between the interface chip IF and the core chips is performed in parallel. This point is the important difference between the common SDRAM and the core chips CC 0  to CC 7 . However, all of the prefetched parallel data do not need to be input/output using the different through silicon vias TSV, and partial parallel/serial conversion may be performed in the core chips CC 0  to CC 7  and the number of through silicon vias TSV that are needed for each DQ may be reduced. For example, all of data of 64 bits for each DQ do not need to be input/output using the different through silicon vias TSV, and 2-bit parallel/serial conversion may be performed in the core chips CC 0  to CC 7  and the number of through silicon vias TSV that are needed for each DQ may be reduced to ½ (32). 
     To the data latch circuit  25 , a function for enabling a test in an interface chip unit is added. The interface chip does not have the back end unit. For this reason, the interface chip cannot be operated as a single chip in principle. However, if the interface chip never operates as the single chip, an operation test of the interface chip in a wafer state may not be performed. This means that the semiconductor memory device  10  cannot be tested in case an assembly process of the interface chip and the plural core chips is not executed, and the interface chip is tested by testing the semiconductor memory device  10 . In this case, when a defect that cannot be recovered exists in the interface chip, the entire semiconductor memory device  10  is not available. In consideration of this point, in this embodiment, a portion of a pseudo back end unit for a test is provided in the data latch circuit  25 , and a simple memory function is enabled at the time of a test. 
     The power supply terminals  17   a  and  17   b  are terminals to which power supply potentials VDD and VSS are supplied, respectively. The power supply terminals  17   a  and  17   b  are connected to a power-on detecting circuit  43  provided in the interface chip IF and are also connected to the core chips CC 0  to CC 7  through the through silicon vias TSV. The power-on detecting circuit  43  detects the supply of power. On detecting the supply of power, the power-on detecting circuit activates a layer address control circuit  45  on the interface chip IF. 
     The layer address control circuit  45  changes a layer address due to the I/O configuration of the semiconductor device  10  according to the present embodiment. As described above, the semiconductor memory device  10  includes 16 data input/output terminals  14 . Thereby, a maximum I/O number can be set to 16 bits (DQ 0  to DQ 15 ). However, the I/O number is not fixed to 16 bits and may be set to 8 bits (DQ 0  to DQ 7 ) or 4 bits (DQ 0  to DQ 3 ). The address allocation is changed according to the I/O number and the layer address is also changed. The layer address control circuit  45  changes the address allocation according to the I/O number and is commonly connected to the core chips CC 0  to CC 7  through the through silicon vias TSV. 
     The interface chip IF is also provided with a layer address setting circuit  44 . The layer address setting circuit  44  is connected to the core chips CC 0  to CC 7  through the through silicon vias TSV. The layer address setting circuit  44  is cascade-connected to the layer address generating circuit  46  of the core chips CC 0  to CC 7  using the through silicon via TSV 2  of the type shown in  FIG. 2B , and reads out the layer addresses set to the core chips CC 0  to CC 7  at testing. 
     The interface chip IF is also provided with a defective chip information holding circuit  33 . When a defective core chip that does not normally operates is discovered after an assembly, the defective chip information holding circuit  33  holds its chip number. The defective chip information holding circuit  33  is connected to the core chips CC 0  to CC 7  through the through silicon vias TSV. The defective chip information holding circuit  33  is connected to the core chips CC 0  to CC 7  while being shifted, using the through silicon via TSV 3  of the type shown in  FIG. 2C . 
     The interface chip IF further includes a test mode register  34  and a test circuit  35 . Each of the test mode register  34  and the test circuit  35  is connected to the core chips CC 0  to CC 7  with the through silicon via TSV 3  of the type shown in  FIG. 2C  while being shifted. 
     The test mode register  34  receives a test mode signal TM (IF) and a test layer activation signal TLA from the command decoder/control logic  32  and the mode register  42 . These signals are input from the command terminals  12   a  to  12   e  and the address terminal  13  as the command signal and the address signal, respectively. 
     The test mode signal TM (IF) is a signal that indicates whether the semiconductor memory device  10  is set in a parallel test mode set and whether the parallel test outputs its test result in one bit or a plurality of bits. The test mode register  34  generates various test control signals (an on-chip comparison test signal TOCCIF, a parallel test signal TPARADTIF, and a multibit output parallel test signal TPARAPIF) in response to the test mode signal TM (IF), and supplies the test control signals to the test circuit  35 . Details of the test control signals are described later. 
     The test layer activation signal TLA is a signal that designates one or a plurality of core chips to be subject to the parallel test. The test mode register  34  generates test layer activation signals TLSE&lt; 0 &gt; to TLSE&lt; 7 &gt; respectively corresponding to the core chips CC 0  to CC 7  in response to the test layer activation signal TLA. The test mode register  34  then outputs the test layer activation signals TLSE&lt; 0 &gt; to TLSE&lt; 7 &gt; to a layer address comparison circuit  47  (described later) of each of the core chips via the through silicon via TSV 3  of the type shown in  FIG. 2C . 
     Details of the test circuit  35  are described later. 
     The above description is the outline of the connection relationship between the external terminals and the interface chip IF and the circuit configuration of the interface chip IF. Next, the circuit configuration of the core chips CC 0  to CC 7  will be described. 
     As shown in  FIG. 4 , memory cell arrays  50  that are included in the core chips CC 0  to CC 7  performing the back end function are divided into eight banks. A bank is a unit that can individually receive a command. That is, the individual banks can be independently and exclusively controlled. From the outside of the semiconductor memory device  10 , each back can be independently accessed. For example, a part of the memory cell array  50  belonging to the bank  1  and another part of the memory cell array  50  belonging to the bank  2  are controlled nonexclusively. That is, word lines WL and bit lines BL corresponding to each banks respectively are independently accessed at same period by different commands one another. For example, while the bank  1  is maintained to be active (the word lines and the bit lines are controlled to be active), the bank  2  can be controlled to be active. However, the banks shares the external terminals (for example, plural control terminals and plural I/O terminals) of the semiconductor memory device  10 . In the memory cell array  50 , the plural word lines WL and the plural bit lines BL intersect each other, and memory cells MC are disposed at intersections thereof (in  FIG. 4 , only one word line WL, one bit line BL, and one memory cell MC are shown). The word line WL is selected by a row decoder  51 . The bit line BL is connected to a corresponding sense amplifier SA in a sense circuit  53 . The sense amplifier SA is selected by a column decoder  52 . 
     The row decoder  51  is controlled by a row address supplied from a row control circuit  61 . The row control circuit  61  includes an address buffer  61   a  that receives a row address supplied from the interface chip IF through the through silicon via TSV, and the row address that is buffered by the address buffer  61   a  is supplied to the row decoder  51 . The address signal that is supplied through the through silicon via TSV is supplied to the row control circuit  61  through the input buffer B 1 . The row control circuit  61  also includes a refresh counter  61   b . When a refresh signal is issued by a control logic circuit  63 , a row address that is indicated by the refresh counter  61   b  is supplied to the row decoder  51 . 
     The column decoder  52  is controlled by a column address supplied from a column control circuit  62 . The column control circuit  62  includes an address buffer  62   a  that receives the column address supplied from the interface chip IF through the through silicon via TSV, and the column address that is buffered by the address buffer  62   a  is supplied to the column decoder  52 . The column control circuit  62  also includes a burst counter  62   b  that counts the burst length. 
     The sense amplifier SA selected by the column decoder  52  is connected to the data control circuit  54  through a data amplifier  56  and sub-amplifiers which are not shown in the drawings. Thereby, read data of 8 bits (=prefetch number) for each I/O (DQ) is output from the data control circuit  54  at reading, and write data of 8 bits is input to the data control circuit  54  at writing. The data control circuit  54  and the interface chip IF are connected in parallel through the through silicon via TSV. 
     The control logic circuit  63  receives an internal command ICMD supplied from the interface chip IF through the through silicon via TSV and controls the row control circuit  61  and the column control circuit  62 , based on the internal command ICMD. In other words, the control logic circuit  63  is a circuit that controls read/write operation to memory cell array  50  in response to the clock signal, the address signal, and the control signal. 
     The control logic circuit  63  is connected to a layer address comparing circuit (chip information comparing circuit)  47 . The layer address comparing circuit  47  detects whether the corresponding core chip is target of access, and the detection is performed by comparing a SEL (chip selection information) which is a part of the address signal supplied from the interface chip IF through the through silicon via TSV or test layer activation signal TLSE and a layer address LID (chip identification information) set to the layer address generating circuit  46 . 
     In the layer address generating circuit  46 , unique layer addresses are set to the core chips CC 0  to CC 7 , respectively, at initialization. A method of setting the layer addresses is as follows. First, after the semiconductor memory device  10  is initialized, a minimum value (0, 0, 0) as an initial value is set to the layer address generating circuits  46  of the core chips CC 0  to CC 7 . The layer address generating circuits  46  of the core chips CC 0  to CC 7  are cascade-connected using the through silicon vias TSV of the type shown in  FIG. 2B , and have increment circuits provided therein. The layer address (0, 0, 0) that is set to the layer address generating circuit  46  of the core chip CC 0  of the uppermost layer is transmitted to the layer address generating circuit  46  of the second core chip CC 1  through the through silicon via TSV and is incremented. As a result, a different layer address (0, 0, 1) is generated. Hereinafter, in the same way as the above case, the generated layer addresses are transmitted to the core chips of the lower layers and the layer address generating circuits  46  in the core chips increment the transmitted layer addresses. A maximum value (1, 1, 1) as a layer address is set to the layer address generating circuit  46  of the core chip CC 7  of the lowermost layer. Thereby, the unique layer addresses are set to the core chips CC 0  to CC 7 , respectively. 
     The layer address generating circuit  46  is provided with a defective chip signal DEF supplied from the defective chip information holding circuit  33  of the interface chip IF, through the through silicon via TSV. As the defective chip signal DEF is supplied to the individual core chips CC 0  to CC 7  using the through silicon via TSV 3  of the type shown in  FIG. 2C , the defective chip signals DEF can be supplied to the core chips CC 0  to CC 7 , individually. The defective chip signal DEF is activated when the corresponding core chip is a defective chip. When the defective chip signal DEF is activated, the layer address generating circuit  46  transmits, to the core chip of the lower layer, a non-incremented layer address, not an incremented layer address. The defective chip signal DEF is also supplied to the control logic circuit  63 . When the defective chip signal DEF is activated, the control logic circuit  63  is completely halted. Thereby, the defective core chip performs neither read operation nor write operation, even though an address signal or a command signal is input from the interface chip IF. 
     An output of the control logic circuit  63  is also supplied to a mode register  64 . When an output of the control logic circuit  63  shows a mode register set, the mode register  64  is updated by an address signal. Thereby, operation modes of the core chips CC 0  to CC 7  are set. 
     Each of the core chips CC 0  to CC 7  has an internal voltage generating circuit  70 . The internal voltage generating circuit  70  is provided with power supply potentials VDD and VSS. The internal voltage generating circuit  70  receives these power supply potentials and generates various internal voltages. As the internal voltages that are generated by the internal voltage generating circuit  70 , an internal voltage VPERI (≈VDD) for operation power of various peripheral circuits, an internal voltage VARY (&lt;VDD) for an array voltage of the memory cell array  50 , and an internal voltage VPP (&gt;VDD) for an activation potential of the word line WL are included. In each of the core chips CC 0  to CC 7 , a power-on detecting circuit  71  is also provided. When the supply of power is detected, the power-on detecting circuit  71  resets various internal circuits. 
     Each of the core chips CC 0  to CC 7  further includes a test mode register  66  and a test circuit  67 . The test mode register  66  receives a test mode signal TM (Core) from the mode register  64 . The test mode signal TM (Core) is a signal that is input from the address terminal  13  as the address signal, indicating a parallel test mode set, similar to the test mode signal TM (IF), and whether to output the test result in one bit or a plurality of bits. The test mode register generates various test control signals (an on-chip comparison test signal TOCC, a parallel test signal TPARADT, and a multibit output parallel test signal TPARAP) in response to the test mode signal TM (Core), and supplies the test control signals to the test circuit  67 . Details of the test control signals are described later. 
     The test circuit  67  is connected to the test circuit  35  in the interface chip IF via the through silicon via TSV 3  of the type shown in  FIG. 2C . The test circuit  67 , at the time of a parallel test, has a function of reading test data written in advance in a plurality of memory cells to be tested from the data amplifier  56  and comparing the data and a function of outputting a comparison result (a layer test result signal) through different current paths that vary from one core chip to another (a through silicon via path constituted by a plurality of through silicon vias TSV). 
     The peripheral circuits in the core chips CC 0  to CC 7  operates in synchronization with the internal clock signal ICLK that is supplied from the interface chip IF through the through silicon via TSV. The internal clock signal ICLK supplied through the through silicon via TSV is supplied to the various peripheral circuits through the input buffer B 2 . 
     The above description is the basic circuit configuration of the core chips CC 0  to CC 7 . In the core chips CC 0  to CC 7 , the front end unit for an interface with the external device is not provided. Therefore the core chip cannot operate as a single chip in principle. However, if the core chip never operates as the single chip, an operation test of the core chip in a wafer state may not be performed. This means that the semiconductor memory device  10  cannot be tested, before the interface chip and the plural core chips are fully assembled. In other words, the individual core chips are tested when testing the semiconductor memory device  10 . When unrecoverable defect exists in the core chips, the entire semiconductor memory device  10  is led to be unavailable. In this embodiment, in the core chips CC 0  to CC 7 , a portion of a pseudo front end unit, for testing, that includes some test pads TP and a test front end unit of a test command decoder  65  is provided, and an address signal or a command signal can be input from the test pads TP. It is noted that the test front end unit is provided for a simple test in a wafer test, and does not have all of the front end functions in the interface chip. For example, since an operation frequency of the core chips is lower than an operation frequency of the front end unit, the test front end unit can be simply realized with a circuit that performs a test with a low frequency. 
     The test pads TP include a test pad TP 1  supplied with the clock signal, a test pad TP 2  supplied with the address signal, test pads TP 3  supplied with the command signal, a test pad TP 4  for performing input/output of test data, a test pad TP 5  for performing input/output of data strobe signal, test pads  6  for supplying power-supply voltages, test pads TP 7  for drawing output data of test circuit  67 , and a test pad TP 8  for supplying a signal PWB indicating a wafer test mode set to the test circuit  67 . A wafer test output buffer  68  is provided between the test pads TP 7  and the test circuit  67 . 
     A common external command (not decoded) is input at testing. Therefore, the test command decoder  65  is also provided in each of the core chips CC 0  to CC 7 . Because serial test data is input and output at testing, a test input/output circuit  55  is also provided in each of the core chips CC 0  to CC 7 . 
     This is the entire configuration of the semiconductor memory device  10 . Because in the semiconductor memory device  10 , the 8 core chips of 1 Gb are laminated, the semiconductor memory device  10  has a memory capacity of 8 Gb in total. Because the chip selection signal /CS is input to one terminal (chip selection terminal), the semiconductor memory device is recognized as a single DRAM having the memory capacity of 8 Gb, in view of the controller. 
       FIG. 5  is a schematic cross section of a circuit including the through silicon via group TSV 3  that constitutes current paths C 0  to C 7  connecting the test circuit  35  and the test circuit  67 . As shown in  FIG. 5 , through silicon vias for parallel test TSVPTm&lt;n&gt; provided in each of the core chips are included in the through silicon via TSV group  3 , where m and n are integers from 0 to 7. In a similar manner, there may be a case that it is indicated that a structure corresponds to a core chip CCn by attaching &lt;n&gt;. 
     The through silicon vias for parallel test TSVPTm&lt;n&gt; are arranged at the same position in a planar view for each of the value m. In each core chip CCn, the through silicon vias for parallel test TSVPTm&lt;n&gt; are arranged at regular intervals in the order from the through silicon via for parallel test TSVPT 0 &lt;n&gt; to the through silicon via for parallel test TSVPT 7 &lt;n&gt; from the left in  FIG. 5 . The test circuits  67 &lt;n&gt; arranged in the core chip CCn are respectively connected to the through silicon vias for parallel test TSVPT 0 &lt;n&gt;. 
     The through silicon via for parallel test TSVPTm&lt; 0 &gt; (m=0 to 6) provided on the core chip CC 0  is connected to a through silicon vias for parallel test TSVPT(m+1)&lt; 1 &gt; provided on the core chip CC 1  that is located right below the core chip CC 0 , respectively. The through silicon via for parallel test TSVPT 7 &lt; 0 &gt; is connected to the through silicon via for parallel test TSVPT 0 &lt; 1 &gt;. The same is true for the through silicon vias for parallel test TSVPTm&lt;n&gt; provided on the core chips CC 1  to CC 6 . 
     The interface chip IF includes through silicon via terminals for parallel test TTSVPT 0  to TTSVPT 7 . The through silicon via terminals for parallel test TTSVPT 0  to TTSVPT 7  are respectively connected to the through silicon vias for parallel test TSVPT 0 &lt; 7 &gt; to TSVPT 7 &lt; 7 &gt; provided on the core chip CC 7 . 
     The above connections are summarized as: the through silicon via terminal for parallel test TTSVPT 0 , the through silicon via for parallel test TSVPT 0 &lt; 7 &gt;, the through silicon via for parallel test TSVPT 7 &lt; 6 &gt;, through silicon via for parallel test TSVPT 6 &lt; 5 &gt;, the through silicon via for parallel test TSVPT 5 &lt; 4 &gt;, the through silicon via for parallel test TSVPT 4 &lt; 3 &gt;, the through silicon via for parallel test TSVPT 3 &lt; 2 &gt;, the through silicon via for parallel test TSVPT 2 &lt; 1 &gt;, and the through silicon via for parallel test TSVPT 1 &lt; 0 &gt; are sequentially connected, by which the current path C 0  is constituted. The current path  0  is connected to the test circuit  67 &lt; 7 &gt; via the through silicon vias for parallel test TSVPT 0 &lt; 7 &gt;. The same is true for the other current paths C 1  to C 7 , in which the current paths C 1  to C 7  are respectively connected to the test circuits  67 &lt; 6 &gt; to  67 &lt; 0 &gt; via the through silicon vias for parallel test TSVPT 0 &lt; 6 &gt; to TSVPT 0 &lt; 0 &gt;. 
     In this manner, by constituting the current paths C 0  to C 7  that connect the test circuit  35  and the test circuit  67  with the spirally-connected through silicon via TSV group, the test circuits  67  of the core chips can output the test data from different current paths from each other. Therefore, it is possible to output the layer test result signals of the core chips all together, shortening the time required for the test, as compared to the case of sequentially outputting the test data. In addition, employing the spiral connection makes it possible to take the same configuration for each of the core chips. 
       FIG. 6  is a block diagram showing functional blocks of the test circuit  67 . As shown in  FIG. 6 , the test circuit  67  includes a plurality of comparison circuit units  80 [ 0 ] to  80 [ 7 ] (eight units in the example shown in  FIG. 6 ) and a test output control unit  81 . 
     To each of the comparison circuit units  80 , test data stored in a predetermined number of memory cells designated in advance are supplied from the data amplifier  56 , and the parallel test signal TPARADT is supplied from the test mode register  66 . The parallel test signal TPARADT is a signal that is in an activated (hereinafter called ‘ACT’) state while the parallel test is being executed, and in a non-activated (hereinafter called ‘NAT’) state otherwise. When the parallel test signal TPARADT is in the ACT state, each of the comparison circuit units  80  compresses the data amount of a plurality of test data readout from a memory cell by replacing the test data with one comparison result, and eventually outputs the compressed data to the test output control unit  81  as data of a predetermined number of bits. On the other hand, when the parallel test signal TPARADT is in the NAT state, an output of each of the comparison circuit units  80  becomes a predetermined value regardless of the test data, for example, the high level. 
       FIG. 7  is a block diagram showing an example of the comparison circuit unit  80 . As shown in  FIG. 7 , the comparison circuit unit  80  compares a plurality of test data supplied from the memory cell array via the data amplifier  56  at multiple stages. 
     When performing the parallel test, a predetermined test data pattern is written in advance in a memory cell to be tested. In this example, a data pattern in which all data are the same (high level or low level) is used as the test data pattern. The comparison circuit unit  80  includes Y 2 -/Y 2  comparing units  82 , Y 1 -Y 0  comparing units  83 , Y 11 -/Y 11  comparing units  84 , and an X 13 -/X 13  comparing unit  85 , and performs a 4-stage comparing operation using these comparing units. 
     Each of the Y 2 -/Y 2  comparing units  82  compares data (Data 1  (Y 2 ) and Data 2  (/Y 2 )) stored in two memory cells designated in advance. Specifically, each of the Y 2 -/Y 2  comparing units  82  compares the data (Data 1  (Y 2 ) and Data 2  (/Y 2 )) stored in memory cells in which only a predetermined bit (Y 2 ) of a column address is different. A specific configuration of the Y 2 -/Y 2  comparing unit  82  includes, as shown in  FIG. 7 , a NOR circuit  82   a  and a NAND circuit  82   b  to which the Data 1  (Y 2 ) and the Data 2  (/Y 2 ) are supplied, respectively, a NOT circuit  82   c  to which the parallel test signal TPARADT is supplied, a NOR circuit  82   d  to which an output of the NOR circuit  82   a  and an output of the NOT circuit  82   c  are supplied, and a NAND circuit  82   e  to which an output of the NAND circuit  82   b  and an output of the NOR circuit  82   d  are supplied. By operations of these circuits, an output of the Y 2 -/Y 2  comparing unit  82  (an output of the NAND circuit  82   e ) is non-activated only when the parallel test signal TPARADT is activated and the Data 1  (Y 2 ) and the Data 2  (/Y 2 ) are different from each other, and activated otherwise. 
     Among outputs of the Y 2 -/Y 2  comparing units  82 , outputs in which a predetermined bit of a column address (Y 1  and Y 0 ) is different from each other are compared in the Y 1 -Y 0  comparing units  83  at the second stage. Among outputs of the Y 1 -Y 0  comparing units  83 , outputs in which a predetermined bit of a column address (Y 11 ) is different from each other are compared in the Y 11 -/Y 11  comparing units  84  at the third stage. Outputs of the Y 11 -/Y 11  comparing units  84  are further compared in the X 13 -/X 13  comparing unit  85  at the fourth stage. Finally, a comparison result of the X 13 -/X 13  comparing unit  85  becomes an output TRDATA[k] (k=0 to 7) of the comparison circuit unit  80 . The comparison result TRDATA is a 1-bit data. 
     The comparison circuit unit  80  is arranged at a rate of one per two 1/2 banks, which makes a total of eight comparison circuit units  80  per core chip. 
     Referring back to  FIG. 6 , the on-chip comparison test signal TOCC, the parallel test signal TPARADT, the multibit output parallel test signal TPARAP, and a signal PWB that indicates a wafer test mode set are input to the test output control unit  81 , as well as comparison results TRDATA[ 0 ] to TRDATA[ 7 ] (total of 8-bit data) output from the comparison circuit units  80 [ 0 ] to  80 [ 7 ]. The on-chip comparison test signal TOCC is a signal that is, for example, in the ACT state while a test (a 1-bit output test) in which the test result is output in one bit, such as a burn-in test, is being executed and in the NAT state while a test (a multibit output test) in which the test result is output in a plurality of bits is being executed. On the other hand, the multibit output parallel test signal TPARAP is a signal that is in the NAT state while the 1-bit output test is being executed and in the ACT state while the multibit output test is being executed. The signal PWB is a signal that is in the ACT state when performing a wafer test of each of the core chips and in the NAT state when performing a post-assembly test. 
     When the signal PWB is in the ACT state (the wafer test), the test output control unit  81  generates layer test result signals TDRD[ 0 ] to TDRD[ 7 ] based on the comparison results TRDATA[ 0 ] to TRDATA[ 7 ] of the comparison circuit units  80 [ 0 ] to  80 [ 7 ]. At this time, if the on-chip comparison test signal TOCC is in the NAT state (the multibit output test) and if the multibit output parallel test signal TPARAP is in the ACT state (the multibit output test), the test output control unit  81  assigns the comparison results TRDATA[ 0 ] to TRDATA[ 7 ] to the layer test result signals TDRD[ 0 ] to TDRD[ 7 ], respectively. On the other hand, if the on-chip comparison test signal TOCC is in the ACT state (the 1-bit output test) and if the multibit output parallel test signal TPARAP is in the NAT state (the 1-bit output test), the test output control unit  81  generates a 1-bit layer test result signal based on the comparison results TRDATA[ 0 ] to TRDATA[ 7 ], and assigns this layer test result signal to all the layer test result signals TDRD[ 0 ] to TDRD[ 7 ]. Therefore, in this case, the layer test result signals TDRD[ 0 ] to TDRD[ 7 ] become the same data. The test output control unit  81  outputs the layer test result signals TDRD[ 0 ] to TDRD[ 7 ] generated in the above manner to the test pad TP 7  via the wafer test output buffer  68 . 
     On the other hand, when the signal PWB is in the NAT state (the post-assembly test), the test output control unit  81  generates a 1-bit layer test result signal TRDATAL&lt;n&gt; based on the comparison results TRDATA[ 0 ] to TRDATA[ 7 ] of the comparison circuit units  80  [ 0 ] to  80 [ 7 ], and outputs the layer test result signal TRDATAL&lt;n&gt; to the through silicon vias for parallel test TSVPT 0 &lt;n&gt;. 
       FIG. 8  is a block diagram showing an example of the test output control unit  81 . In this example, the on-chip comparison test signal TOCC and the parallel test signal TPARADT are high-active signals and the multibit output parallel test signal TPARAP and the signal PWB are low-active signals. 
     As shown in  FIG. 8 , the test output control unit  81  includes an AND circuit  81   a  to which the comparison results TRDATA[ 0 ] to TRDATA[ 7 ] are supplied, a D-Latch circuit  81   b  to which an output of the AND circuit  81   a  and the on-chip comparison test signal TOCC are input, a NOT circuit  81   c  to which the multibit output parallel test signal TPARAP is supplied, NAND circuits  81   d [ 0 ] to  81   d [ 7 ] to which an output of the NOT circuit  81   c , the parallel test signal TPARADT, and inverted data of the comparison results TRDATA[ 0 ] to TRDATA[ 7 ] are respectively supplied, AND circuits  81   e [ 0 ] to  81   e [ 7 ] to which an output TRCOMPT (1DQ) of the D-Latch circuit  81   b  and outputs of the NAND circuits  81   d [ 0 ] to  81   d [ 7 ] are respectively supplied, an RDFIFO  81   f  to which each of output signals TDRD[ 0 ] to TDRD[ 7 ] of the AND circuits  81   e [ 0 ] to  81   e [ 7 ] is supplied, and an AND circuit  81   g  to which each of the output signals TDRD[ 0 ] to TDRD[ 7 ] of the AND circuits  81   e [ 0 ] to  81   e [ 7 ] and the signal PWB are supplied. Among these circuits, the D-Latch circuit  81   b  is a circuit that outputs a high level signal when the on-chip comparison test signal TOCC is the low level (the NAT state) and an output of the AND circuit  81   a  when the on-chip comparison test signal TOCC is the high level (the ACT state). The RDFIFO  81   f  is a circuit that is synchronized with rising and falling of the internal clock signal ICLK, converts the output signals TDRD[ 0 ] to TDRD[ 7 ] into 4DQ data, and outputs the converted data. 
     Table 1 shows a relation between the signal PWB, the on-chip comparison test signal TOCC, the parallel test signal TPARADT, the multibit output parallel test signal TPARAP, an output destination of the layer test result signal, and the number of output bits. When performing a multibit output wafer test, the signal PWB, the on-chip comparison test signal TOCC, the parallel test signal TPARADT, and the multibit output parallel test signal TPARAP are set to low, low, high, and low, respectively. This allows the RDFIFO  81   f  to output the layer test result signals TDRD[ 0 ] to TDRD[ 7 ] to which the comparison results TRDATA[ 0 ] to TRDATA[ 7 ] are assigned, respectively, to the wafer test output buffer  68 . In this case, the data amount of the layer test result signal is 8 bits. When performing a 1-bit output wafer test, the signal PWB, the on-chip comparison test signal TOCC, the parallel test signal TPARADT, and the multibit output parallel test signal TPARAP are set to low, high, high, and high, respectively. This allows the RDFIFO  81   f  to output the layer test result signals TDRD[ 0 ] to TDRD[ 7 ] that are the same data to the wafer test output buffer  68 . In this case, the data amount of the layer test result signal is 1 bit. When performing a post assembly test, the signal PWB, the on-chip comparison test signal TOCC, the parallel test signal TPARADT, and the multibit output parallel test signal TPARAP are all set to high. This allows the AND circuit  81   g  to output the 1-bit layer test result signal TRDATAL&lt;n&gt; to the through silicon via TSVPT 0 &lt;n&gt;. In this case, the data amount of the layer test result signal is 1 bit. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                   
                   
                 Output 
                 Output data 
               
               
                 Test type 
                 PWB 
                 TOCC 
                 TPARADT 
                 TPARAP 
                 destination 
                 amount 
               
               
                   
               
             
            
               
                 Wafer test 
                 L 
                 L 
                 H 
                 L 
                 Wafer test 
                 8 
               
               
                 Multibit 
                 (ACT) 
                 (NAT) 
                 (ACT) 
                 (ACT) 
                 input/ 
               
               
                 output test 
                   
                   
                   
                   
                 output 
               
               
                 Wafer test 
                 L 
                 H 
                 H 
                 H 
                 buffer 
                 1 
               
               
                 1-bit 
                 (ACT) 
                 (ACT) 
                 (ACT) 
                 (NAT) 
               
               
                 output test 
               
               
                 Post-assembly 
                 H 
                 H 
                 H 
                 H 
                 TSVPT0 
                 1 
               
               
                 test 
                 (NAT) 
                 (ACT) 
                 (ACT) 
                 (NAT) 
               
               
                   
               
            
           
         
       
     
       FIG. 9  is a schematic block diagram showing another example of the test output control unit  81 . The example shown in  FIG. 9  is different from the example shown in  FIG. 8  in that the output TRCOMPT of the D-Latch circuit  81   b  and the signal PWB are supplied to the AND circuit  81   g , but the relation between the signal PWB, the on-chip comparison test signal TOCC, the parallel test signal TPARADT, the multibit output parallel test signal TPARAP, an output destination of the layer test result signal, and the number of output bits is the same as that in the example shown in  FIG. 8 . In this manner, the specific circuit configuration of the test output control unit  81  can be obtained by adopting various variations. 
       FIG. 10  is a schematic block diagram showing functional blocks of the test circuit  35 . As shown in  FIG. 10 , the test circuit  35  includes a test output control unit  87 . The on-chip comparison test signal TOCCIF, the parallel test signal TPARADTIF, and the multibit output parallel test signal TPARAPIF are supplied to the test output control unit  87 , as well as the 1-bit layer test result signals TRDATAL&lt; 0 &gt; to TRDATAL&lt; 7 &gt; output from the core chips CC 0  to CC 7 . The on-chip comparison test signal TOCCIF, the parallel test signal TPARADTIF, and the multibit output parallel test signal TPARAPIF are the same signals as the on-chip comparison test signal TOCC, the parallel test signal TPARADT, and the multibit output parallel test signal TPARAP described above, respectively. 
     If the on-chip comparison test signal TOCCIF is in the NAT state (the multibit output test) and if the multibit output parallel test signal TPARAPIF is in the ACT state (the multibit output test), the test output control unit  87  assigns the layer test result signals TRDATAL&lt;O&gt; to TRDATAL&lt; 7 &gt; to layer test result signals TDRDL&lt; 0 &gt; to TDRDL&lt; 7 &gt;, respectively. On the other hand, if the on-chip comparison test signal TOCCIF is in the ACT state (the 1-bit output test) and if the multibit output parallel test signal TPARAPIF is in the NAT state (the 1-bit output test), the test output control unit  87  generates a 1-bit layer test result signal based on the layer test result signals TRDATAL&lt; 0 &gt; to TRDATAL&lt; 7 &gt;, and assigns this layer test result signal to all the layer test result signals TDRDL&lt; 0 &gt; to TDRDL&lt; 7 &gt;. 
       FIG. 11  is a schematic block diagram showing an example of the test output control unit  87 . In this example, the on-chip comparison test signal TOCCIF and the parallel test signal TPARADTIF are high-active signals and the multibit output parallel test signal TPARAPIF is a low-active signal. 
     As shown in  FIG. 11 , the test output control unit  87  includes a NAND circuit  87   a  to which the layer test result signals TRDATAL&lt; 0 &gt; to TRDATAL&lt; 7 &gt; are supplied, a NAND circuit  87   b  to which an output of the NAND circuit  87   a  and the on-chip comparison test signal TOCCIF are input, a NOT circuit  87   c  to which the multibit output parallel test signal TPARAPIF is supplied, NAND circuits  87   d &lt; 0 &gt; to  87   d &lt; 7 &gt; to which an output of the NOT circuit  87   c , the parallel test signal TPARADTIF, and inverted data of the layer test result signals TRDATAL&lt; 0 &gt; to TRDATAL&lt; 7 &gt; are respectively supplied, AND circuits  87   e &lt; 0 &gt; to  87   e &lt; 7 &gt; to which an output TRCOMPT (1DQ) of the NAND circuit  87   b  and outputs of the NAND circuits  87   d &lt; 0 &gt; to  87   d &lt; 7 &gt; are respectively supplied, and an RDFIFO  87   f  to which each of output signals TDRDL&lt; 0 &gt; to TDRDL&lt; 7 &gt; of the AND circuits  87   e &lt; 0 &gt; to  87   e &lt; 7 &gt; is supplied. Among these circuits, the RDFIFO  87   f  is a circuit that is synchronized with rising and falling of the internal clock signal ICLK, converts the output signals TDRDL&lt; 0 &gt; to TDRDL&lt; 7 &gt; into 4DQ data, and outputs the converted data. 
     Table 2 shows a relation between the on-chip comparison test signal TOCCIF, the parallel test signal TPARADTIF, the multibit output parallel test signal TPARAPIF, and the number of output bits of the layer test result signal. When performing a multibit output post-assembly test, the on-chip comparison test signal TOCCIF, the parallel test signal TPARADTIF, and the multibit output parallel test signal TPARAPIF are set to low, high, and low, respectively. This allows the RDFIFO  87   f  to output the layer test result signals TDRDL&lt; 0 &gt; to TDRDL&lt; 7 &gt; to which the layer test result signals TRDATAL&lt; 0 &gt; to TRDATAL&lt; 7 &gt; are assigned, respectively, to the input/output buffer circuit  23 . In this case, the data amount of the layer test result signal is 8 bits. When performing a 1-bit output post-assembly test, the on-chip comparison test signal TOCCIF, the parallel test signal TPARADTIF, and the multibit output parallel test signal TPARAPIF are all set to high. This allows the RDFIFO  87   f  to output the layer test result signals TDRDL&lt; 0 &gt; to TDRDL&lt; 7 &gt; that are the same data to the input/output buffer circuit  23 . In this case, the data amount of the layer test result signal is 1 bit. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                   
                   
                 Output 
               
               
                   
                   
                   
                   
                 data 
               
               
                 Test type 
                 TOCCIF 
                 TPARADTIF 
                 TPARAPIF 
                 amount 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Post-assembly test 
                 L 
                 H 
                 L 
                 8 
               
               
                 Multibit output test 
                 (NAT) 
                 (ACT) 
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                 Post-assembly test 
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                 1-bit output test 
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       FIG. 12  is a flowchart showing a process flow of the post-assembly test. First, a test layer activation signal TLA that designates a core chip to be subject to a parallel test is supplied to the test mode register  34  by inputting predetermined address signal and command signal from outside (Step S 1 ). This allows the core chip to be subject to the test to be activated, and the other core chips to be non-activated. 
     Subsequently, a test mode signal TM (Core) is supplied to the activated core chip by inputting a predetermined address signal from outside. Furthermore a test data pattern is written in a memory cell array provided in the core chip to be subject to the test by using the control logic circuit  63  on each core chip (Step S 2 ). 
     Thereafter, test data is read from the memory cell array in the test circuit  67  of each core chip, and a layer test result signal TRDATAL&lt;n&gt; is generated (Step S 3 ). Furthermore, the generated layer test result signal TRDATAL&lt;n&gt; is output from the through silicon via TSVPT 0 &lt;n&gt; of each core chip (Step S 4 ). Because the through silicon via TSVPT 0 &lt;n&gt; is spirally connected, there will be no collision between the layer test result signals TRDATAL&lt;n&gt; output from the core chips at this step. 
     Finally, the test circuit  35  of the interface chip IF receives the layer test result signals TRDATAL&lt;n&gt; output from the core chips, and outputs the layer test result signals TRDATAL&lt;n&gt; to outside via the input/output buffer circuit  23  (Step S 5 ). 
     As explained above, in the semiconductor device  10  according to the present embodiment, because the layer test result signals are output from different current paths that vary from one core chip to another when performing a post-assembly test, it is possible to output the layer test result signals of a plurality of core chips all together. Therefore, the time required for the post-assembly test of the semiconductor device is shortened, as compared to a case of sequentially outputting layer test result signals of a plurality of core chips. 
       FIG. 13  is a block diagram showing the configuration of a data processing system  500  using the semiconductor memory device  10  according to this embodiment. 
     The data processing system  500  shown in  FIG. 13  has a configuration in which a data processor  520  and the semiconductor device (DRAM)  10  according to this embodiment is mutually connected via a system bus  510 . The data processor  520 , for example, includes micro-processor (MPU) or digital signal processor (DSP). But it is not limited to them. In  FIG. 13 , for the sake of shorthand, the data processor  520  and the DRAM  10  are connected via the system bus  510 . But they may be connected using a local bus not via the system bus  510 . 
     In  FIG. 13 , for the sake of shorthand, only one set of the system bus  510  is drawn. But a plurality of system buses  510  may be provided in serial or parallel manner via some connectors etc., if needed. In the data processing system  500  shown in  FIG. 13 , a storage device  540 , I/O device  550 , and ROM  560  are also connected to the system bus  510 . But these components are not in dispensable. 
     The storage device  540  may be a hard disk drive, an optical disk drive, or a flash memory. The I/O device  550  may be one or more display devices such as a liquid display, but not limited to, or one or more input devices such as a keyboard, a mouse, but not limited to. 
     I/O device  550  can be only one of the input device and the output device. 
     Though only one component is drawn for each of the components shown in  FIG. 13 , the number of each of the components is not limited to one. The data processing system  500  can include a plurality of each of the components. 
     It is apparent that the present invention is not limited to the above embodiments, but may be modified and changed without departing from the scope and spirit of the invention. 
     For example, in the above described embodiment, the DDR3-type SDRAM is used as the core chip, but the present invention is not limited thereto. Accordingly, the core chip may be a DRAM other than the DDR3-type and may be a semiconductor memory (SRAM, PRAM, MRAM, flash memory, etc.) other than the DRAM. The number of core chips is not restricted to 8. 
     In the above embodiment, while an example in which the present invention is applied to a semiconductor device including a plurality of core chips and an interface chip has been explained, the present invention is also applicable to the multichip package mentioned above.