Abstract: Signals outputted from an I/O buffer with a parallel drive configuration are stabilized for reliability enhancement. Each I/O cell has a complementary I/O cell that outputs one output signal as a complementary signal made up of a non-inverted signal and an inverted signal. Two I/O cells are coupled in parallel. Output portions of first inverters are coupled together through a first wiring; and output portions of second inverters are coupled together through a second wiring. The first wiring is formed on the lower side of the I/O cells so that it is astride the two I/O cells, and the second wiring is formed above the first wiring so that it is astride the two I/O cells. The wirings are laid out so that the wiring length of the first wiring and the wiring length of the second wiring are substantially equal to each other.

Abstract: Signals outputted from an I/O buffer with a parallel drive configuration are stabilized for reliability enhancement. Each I/O cell has a complementary I/O cell that outputs one output signal as a complementary signal made up of a non-inverted signal and an inverted signal. Two I/O cells are coupled in parallel. Output portions of first inverters are coupled together through a first wiring; and output portions of second inverters are coupled together through a second wiring. The first wiring is formed on the lower side of the I/O cells so that it is astride the two I/O cells, and the second wiring is formed above the first wiring so that it is astride the two I/O cells. The wirings are laid out so that the wiring length of the first wiring and the wiring length of the second wiring are substantially equal to each other.

Abstract: A test signal applied to an embedded memory is changed in synchronization with a test clock signal, set to an invalidated state by an asynchronous control signal asynchronous to the test clock signal and then is applied to a memory. The memory takes in a received signal in synchronization with a memory clock signal. An invalid data generating circuit modifies the test signal in accordance with the asynchronous control signal and generates a test signal and to apply the test signal to the memory. A period of an invalid state of the modified test signal can be adjusted and therefore, by monitoring a changing timing of the asynchronous control signal PTX with an external tester, setup and hold times of a signal for the memory can be measured. Setup and hold times and an access time for an embedded memory can be correctly measured.

Abstract: An XOR gate receives an input from a pair of read data lines to output a self-precharge signal when there is an increased potential difference between the paired read data lines. Thus, immediately after the increased potential difference between the paired read data lines occurs upon issuance of a read command, a precharge operation is autonomically performed. Therefore, no external precharge command is necessary when the read command is issued and thus a higher-speed operation is easily achieved.

Abstract: Internal read out data bits are divided into a plurality of data groups, and data bits in corresponding positions in different data groups are paired off. A determination gate is provided to each pair of data bits, and determining operation is performed in each pair to compress the result of determination to finally generate a 1-bit flag indicating a match/mismatch in logic level among the internal read out data. Consequently, a multi-bit test circuit that has a reduced layout area and can perform high-speed multi-bit determination is provided.

Abstract: In a semiconductor memory device having a shared sense amplifier configuration, a control circuit outputting a bit line isolation signal latches a block selection signal in accordance with a change in a trigger signal. With this configuration, when the same block is selected, no change is caused in the bit line isolation signal. Consequently, charge/discharge current is reduced, and power consumption is reduced. Since a specific bit in a refresh counter is not used, unlike the conventional technique, the design changes little even in the case of changing the configuration of an array.

Abstract: In a semiconductor memory device having a shared sense amplifier configuration, a control circuit outputting a-bit line isolation signal latches a block selection signal in accordance with a change in a trigger signal. With this configuration, when the same block is selected, no change is caused in the bit line isolation signal. Consequently, charge/discharge current is reduced, and power consumption is reduced. Since a specific bit in a refresh counter is not used, unlike the conventional technique, the design changes little even in the case of changing the configuration of an array.

Abstract: A semiconductor memory device includes an isolation unit isolating a bit line in a first region including a memory cell formed of a thick film transistor and a second region including a sense amplifier formed of a thin film transistor. Voltage supply lines are provided corresponding to respective regions. In a test mode, the isolation unit isolates the two regions. A voltage for testing is supplied from the voltage supply line. Thus, a voltage for testing corresponding to a thick film transistor and a thin film transistor can be supplied to allow efficient execution of a burn-in test.

Abstract: In a semiconductor memory device having a shared sense amplifier configuration, a BLI control circuit outputting a bit line isolation signal BLI is so constructed as to latch a block selection signal RBS in accordance with a change in a trigger signal RXT. With the configuration, while the same block is selected, no change is caused in signal BLI. Consequently, a charge/discharge current is reduced, and power consumption can be reduced. Since a specific bit in a refresh counter is not used unlike a conventional technique, a change in design is a little even in the case of changing the configuration of an array.

Abstract: A contact hole having an opening diameter smaller than the minimum dimension that can be formed by photolithographic technique is formed. Using an interlayer insulating film 8 formed on a semiconductor substrate as an etching mask, etching is carried out halfway to form an opening 8a. The etching mask is removed, and a TEOS film 10 is formed on the interlayer oxide film 8. The whole surface is then etched anisotropically to form a contact hole 11.

Abstract: A test signal applied to an embedded memory is changed in synchronization with a test clock signal, set to an invalidated state by an asynchronous control signal asynchronous to the test clock signal and then is applied to a memory. The memory takes in a received signal in synchronization with a memory clock signal. An invalid data generating circuit modifies the test signal in accordance with the asynchronous control signal and generates a test signal and to apply the test signal to the memory. A period of an invalid state of the modified test signal can be adjusted and therefore, by monitoring a changing timing of the asynchronous control signal PTX with an external tester, setup and hold times of a signal for the memory can be measured. Setup and hold times and an access time for an embedded memory can be correctly measured.

Abstract: Internal read out data bits are divided into a plurality of data groups, and data bits in corresponding positions in different data groups are paired off. A determination gate is provided to each pair of data bits, and determining operation is performed in each pair to compress the result of determination to finally generate a 1-bit flag indicating a match/mismatch in logic level among the internal read out data. Consequently, a multi-bit test circuit that has a reduced layout area and can perform high-speed multi-bit determination is provided.

Abstract: A voltage down converter includes a first voltage down converting circuit and a second voltage down converting circuit. The first voltage down converting circuit supplies an internal power supply voltage VCCS1 to an internal circuit only during a period T when the internal power supply voltage VCCS1 falls below a predetermined voltage according to a signal DCE. In the first voltage down converting circuit, P channel MOS transistors are selectively activated according to the levels of the plurality of voltages, and a voltage down converting partial circuit supplies a current of an amount corresponding to the level of the external power supply voltage VCC to a power supply node. As a result, even during the period T, the internal power supply voltage can be maintained at a level of the reference voltage.

Abstract: A voltage down converter includes a first voltage down converting circuit and a second voltage down converting circuit. The first voltage down converting circuit supplies an internal power supply voltage VCCS1 to an internal circuit only during a period T when the internal power supply voltage VCCS 1 falls below a predetermined voltage according to a signal DCE. In the first voltage down converting circuit, P channel MOS transistors are selectively activated according to the levels of the plurality of voltages, and a voltage down converting partial circuit supplies a current of an amount corresponding to the level of the external power supply voltage VCC to a power supply node. As a result, even during the period T, the internal power supply voltage can be maintained at a level of the reference voltage.

Abstract: A power supply circuit and an oscillation circuit or the like of noise generation sources are concentrated, and the periphery thereof is surrounded by a guard ring. Guard ring is provided to have bonding pads at least partially thereon. Guard ring is effectively provided utilizing the region below bonding pads, so that effective noise reduction is achieved while preventing increase in chip area.

Abstract: A power supply circuit and an oscillation circuit or the like of noise generation sources are concentrated, and the periphery thereof is surrounded by a guard ring. Guard ring is provided to have bonding pads at least partially thereon. Guard ring is effectively provided utilizing the region below bonding pads, so that effective noise reduction is achieved while preventing increase in chip area.

Abstract: A control circuit portion which controls the operations of memory cells is concentrated in a central portion and heat radiation plates are placed thereon via adhesive. A semiconductor integrated circuit having a function of the MPU or the like is placed above the control circuit portion via a bump electrode. The control circuit portion and a memory block are formed on separate chips respectively.

Abstract: A master control circuit provides access to a corresponding memory block via four local control circuits. The memory blocks are arranged so as to surround the master control circuit and the local control circuits. The amount of delay of a control signal to each memory block is set substantially equal to suppress skew in the control signal. A DRAM of high speed can be realized.

Abstract: A contact hole having an opening diameter smaller than the minimum dimension that can be formed by photolithographic technique is formed. Using an interlayer insulating film 8 formed on a semiconductor substrate as an etching mask, etching is carried out halfway to form an opening 8a. The etching mask is removed, and a TEOS film 10 is formed on the interlayer oxide film 8. The whole surface is then etched anisotropically to form a contact hole 11.

Abstract: A voltage generation circuit includes a voltage comparing circuit to compare a reference voltage signal Vi and an internal power supply voltage Vcc and a current supply transistor to supply current based on the output voltage of the voltage comparing circuit and maintain Vcc. The voltage generation circuit also includes a reference voltage signal generation circuit which responds to a control signal ACT activated for a prescribed time period prior to the operation timing of a load and sets Vi=Vref when control signal ACT is inactive and Vi=Vref+.DELTA.V when control signal ACT is active.