Kabushiki Kaisha Toshiba

Toshiba Corporation

Mitsuru Shimizu

Syuso Fujii

Sumio Tanaka

Yoshio Okada

Kiyofumi Sakurai

Hiroyuki Takenaka

Masaharu Wada

Shozo Saito

Kenji Numata

Tetsuya Yamamoto

Nobuyuki Ikumi

Sadao Imada

A semiconductor memory device includes a memory collar, a repair data analyzer, a BIST block, and a system logic. The memory collar includes a memory cell and a spare cell and have a redundancy function of replacing fail memory cell with the spare cell if fail memory cell exists. The repair data analyzer determines whether or not memory cell included in the memory collar is defective, and generates fail address corresponding to the memory cell determined as being defective. The BIST block operates in synchrony with a first clock signal inputted to a first clock signal terminal in a test operation mode, and controls the operation of the memory collar. The system logic operates in synchrony with a second clock signal inputted to a second clock signal terminal in the test operation mode.

Semiconductor integrated circuit device having a test function

A p-well region (16) is formed in the main surface area of an n-type semiconductor substrate (11). A potential (V.sub.BB) which is lower than an externally input potential is applied to the p-well region (16). In the surface area of the p-well region (16), a first impurity diffused layer (12) of n-type to which the externally input potential (Vin) is applied and a second impurity diffused layer (13) of n-type to which a reference potential is applied are formed. The first impurity diffused layer (12) serves as the drain region of a first MOS transistor (Q9) of n-channel formed in the p-well region (16) and the second impurity diffused layer (13) serves as the drain region of a second MOS transistor (Q10) of n-channel which is also formed in the p-well region (16). The first and second MOS transistors (Q9 and Q10) constitute the input section of an input circuit. The input circuit detects the level of the externally input potential (Vin) by comparing the externally input potential (Vin) with the reference potential (Vref).

Substrate structure of semi-conductor device

A ferroelectric memory having a memory cell array or a plurality of memory cell arrays, word lines, where each memory cell array includes word lines. The memory also includes a plurality of plate lines, where each memory cell array includes some of the plate lines and the word line corresponds with some of the plate lines, a bit line, a word line select circuit for selecting among the word lines, and plurality of plate line select circuits, where each of the plate line select circuit is coupled to an associated plate line.

Ferroelectric memory used for the RFID system, method for driving the

A ferroelectric memory has a memory cell screening test circuit connected to bit lines through switching transistors. In screening, at least one word line is selected, and data is simultaneously written in all memory cells connected to this word line. Since data is not restored after the rewrite, all FRAM cells can be screened under the same condition. By this circuit, a memory cell having a write failure according to the imprint characteristics inherent to the ferroelectric memory is screened.

Ferroelectric memory and screening method therefor

According to this invention, a well region is formed on a semiconductor substrate. An n.sup.+ -type first semiconductor region is formed in the well region, and an input pad for receiving an external signal is connected near the first semiconductor region. This input pad is connected to an input circuit of an integrated circuit constituted by an inverter circuit and to an external terminal for receiving an external signal. N.sup.+ -type second semiconductor regions are formed in the well region located on both sides of the first semiconductor region. A ground potential Vss is applied to these second semiconductor regions. A p.sup.+ -type third semiconductor region is formed around these second semiconductor regions in the well region. The ground potential is applied to the third semiconductor region. Therefore, a parallel circuit formed by a parasitic transistor and a parasitic diode is formed between the input pad and the ground potential. The parasitic transistor is turned on upon electrostatic discharge, and the parasitic diode is turned on when a negative potential for test is applied to the input pad, thereby preventing an erroneous operation of a transistor arranged on the semiconductor substrate.

Semiconductor device having input protection circuit

A nonvolatile ferroelectric memory comprises a memory cell array having memory cells arranged as a matrix array and each including a charge transfer transistor having a source or drain region connected to a bit line and a gate connected to a word line and a ferroelectric capacitor for information storage having one electrode connected to a plate line and the other electrode connected to the drain or source region of the charge transfer transistor. A first dummy line is arranged outside a bit line formed at an end of the memory cell array and second dummy bit lines are arranged between the bit line at the end of the memory cell array and the first dummy bit line. Dummy memory cells are connected to the second dummy bit line and have the same in configuration and size as the memory cells connected to the bit line.

Nonvolatile ferroelectric memory

Circuitry within a ferroelectric memory prevents inversion of the polarization of ferroelectric memory cells caused by a power on reset signal to avoid corruption of data stored therein. A ferroelectric memory includes a memory cell array, a plurality of word lines commonly connected to the gates of the cell transistors in the same row, a plurality of plate lines commonly connected to the plates of the cell capacitors in the same row, a plurality of bit lines commonly connected to one end of the cell transistors in the same row, and a power on reset circuit for generating a power on reset signal of a predetermined level for a predetermined period of time after the power supply is turned on. An erroneous programming prevention circuit within the memory includes a plurality of switching transistors connected between all of the bit lines and plate lines and a plurality of nodes at a predetermined potential. The switching transistors are controlled by the power on reset signal so that they are on for a predetermined period of time.

Fram, fram card, and card system using the same

FRAM, FRAM card, and card system using the same

According to the invention, a well region is formed on a semiconductor substrate. An n.sup.+ -type first semiconductor region is formed in the well region, and an input pad for receiving an external signal is connected near the first semiconductor region. This input pad is connected to an input circuit of an integrated circuit constituted by an inverter circuit and to an external terminal for receiving an external signal. N.sup.+ -type second semiconductor regions are formed in the well region located on both sides of the first semiconductor region. A ground potential Vss is applied to these second semiconductor regions. A p.sup.+ -type third semiconductor region is formed around these second semiconductor regions in the well region. The ground potential is applied to the third semiconductor region. Therefore, a parallel circuit formed by a parasitic transistor and a parasitic diode is formed between the input pad and the ground potential. The parasitic transistor is turned on upon electrostatic discharge, and the parasitic diode is turned on when a negative potential for test is applied to the input pad, thereby preventing an erroneous operation of a transistor arranged on the semiconductor substrate.

Input protection circuit formed in a semiconductor substrate

According to this invention, word line drive circuits are respectively connected to memory cell arrays. These memory cell arrays are respectively driven by the word line drive circuits. Therefore, the potential of a normal word line selected simultaneously with a word line in which a failure has occurred and which is included in a memory cell array can be prevented from being decreased so as to prevent the normal word line from the failure. For this reason, the yield can be increased without unnecessarily using a redundancy circuit.

Semiconductor memory apparatus having a plurality of word line drive

A first power source line is formed around a memory area having a memory cell array, column decoder, row decoder and sense amplifier formed therein. The first power source line is applied with a potential which is obtained by lowering a power source voltage supplied from the exterior. A second power source line is formed in the surrounding region of the first power source line. The second power source line is applied with a ground potential. A first peripheral circuit driven by a voltage between the lowered potential and the ground potential is disposed in an area between the first and second power source lines. The first peripheral circuit is a circuit used for the memory area. A third power source line is formed in the surrounding region of the second power source line. The third power source line is applied with a power source potential supplied from the exterior. A second peripheral circuit driven by a voltage between the power source potential and the ground potential is disposed in an area between the second and third power source lines. The second peripheral circuit is a circuit used for an external circuit of a chip.

Pattern layout of power source lines in semiconductor memory device

A semiconductor memory device is disclosed which comprises a regular row/column memory cell array having blocks obtained by dividing the memory cell array in the column and row directions, a first peripheral circuit irregularly provided between the blocks divided in the column direction, a second peripheral circuit provided between the blocks divided in the row direction and including a first decoder, a third peripheral circuit provided between the first peripheral circuit and the respective block and including a second decoder, and a fourth peripheral circuit provided at the marginal portion of the memory cell array and including bonding pads and input protection circuit.

Semiconductor memory device

A semiconductor memory device such as dynamic random access memories comprises a work line drive circuit provided with two MOS transistors and a word line to which a word line drive signal is supplied, a substrate bias generation circuit for applying a bias voltage to a semiconductor substrate for MOS transistors, a burn-in mode detection circuit for detecting a burn-in test mode signal, and a substrate bias control circuit for controlling the substrate bias generation circuit. When the semiconductor memory device is subjected to a burn-in test, the power supply level Vcc is increased to raise the voltage of the word line drive signal as compared to that at a normal operation. Accordingly, a high level word line drive signal will be applied to cell transistors, thereby performing correct screening thereof.

Semiconductor memory device having burn-in test function

A protection circuit is inserted between a signal input pad and an internal circuit. The protection circuit includes a parasitic bipolar transistor which is obtained by forming high-impurity concentration semiconductor regions in the major-surface region of a substrate. In practice, it is hard to provide a parasitic bipolar transistor of a sufficiently large size, since the reduction of the size of a chip is a recent trend. With this in mind, a third semiconductor region serving as an electron-trapping region is formed in a region outside of the location where the parasitic bipolar transistor is formed. If an excessive voltage produced by ESD or the like is applied to the pad, and the excessive voltage uncontrollable by the parasitic bipolar transistor, the third semiconductor region absorbs the excessive voltage. In particular, where the current capacity of the parasitic bipolar transistor is small, the third semiconductor region reliably prevents electrostatic destruction of a circuit element. Accordingly, the protection circuit enables the parasitic bipolar transistor to be reduced in size, thus contributing to miniaturization of a chip. Moreover, the protection circuit is reliable in operation.

Protection circuit for use in semiconductor integrated circuit device

A semiconductor device comprises a semiconductor chip and a memory array constituted by a plurality of memory blocks formed in the semiconductor chip and each having the essentially same construction and a plurality of bit lines arranged in columns at a predetermined interval. The semiconductor device further comprises a dummy wiring pattern arranged ajacent to the memory array in the semiconductor chip and including a dummy wiring layer set apart from outermost bit lines of each memory block a distance equal to the predetermined interval.

Growing community of inventors

Sakura, Japan

Mitsuru Shimizu