Mitsubishi Denki Kabushiki Kaisha

Kabushiki Kaisha Kobe Seiko Sho

Hiroshi Takagi

Masakazu Nakao

Yoshinori Onoe

Satoru Ikenaga

Hiraku Tsuchiya

Shohei Murakami

Kenzo Ayata

Koichi Fujiwara

Koro Takatsuka

Michihisa Taguchi

Masakazu Itashiki

Takao Shiozawa

Yasuhiko Ohta

Yasuo Suzuki

Toshiyasu Onishi

A memory cell structure with the reduced number of bit line contacts, contributing to high integration and high reliability of a DRAM is provided. Each of memory cells (M1, M2, M3, M4) of the DRAM includes a field effect transistor and a capacitor (I, II, III, IV) connected thereto. The field effect transistor constituting each of the memory cells has a combination of two gates: a transfer gate (A) of a low Vth and a sub-transfer gate (a) of a high Vth, a transfer gate (B) of a high Vth and a sub-transfer gate (b) of a low Vth, a transfer gate (C) of a high Vth and a sub-transfer gate (c) of a low Vth, and a transfer gate (D) of a low Vth and a sub-transfer gate (d) of a high Vth. The four memory cells share a bit line contact.

Dynamic random access memory and manufacturing method thereof

A circuit test of a semiconductor device having a redundant circuit for repairing defective circuit is carried with the fuse portion (21) of the redundant circuit and the bonding pad portion (26) exposed and the wiring layers (23) formed on the semiconductor substrate protected with a first protective layer (32). By this step, metal shavings (29) scraped from the surface of the bonding pad by a tester electrode terminal during the circuit test can be prevented from being directly in contact with the interconnection layers, whereby generation of short circuit can be prevented. Thereafter, the surfaces of the bonding pad portion and the fuse portion are covered with a second protective layer (33) and a third protective layer (25) (polyimide). The surface of the bonding pad portion is exposed by etching. By forming the polyimide film on the bonding pad with the second protective layer interposed therebetween, the alkali solution for etching the polyimide film can be prevented from making rough the surface of the bonding pad.

Semiconductor device having a redundant circuit and method of

A semiconductor device exposed to irradiation (21, 22) of charged particles in a fabrication process thereof includes: at least a first conductive region (3, 1) and a second conductive region (4a, 4b) formed at different positions, electrically insulated from each other; a third coductive region (8 , 9) provided at least over the first conductive region (3, 1) and the second conductive region (4a, 4b); a first insulator layer region (5, 7) sandwiched between the first conductive region (3, 1) and the third conductive region (8, 9) to insulate the first and third conductive regions from each other; and a second insulator layer region (6a, 6b) sandwiched between the second conductive region (4a, 4b) and the third conductive region (8, 9) to insulate the second and third conductive regions from each other, and the second conductive region (4a, 4b) has a portion shaped to cause dielectric breakdown to be more liable to occur in the second insulator layer region (6a, 6b) than in the first insulator layer region (5, 7).

Semiconductor device having dielectric breakdown protection element and

A conductive layer is formed at the step portion in a dicing line formed vertically and horizontally on a wafer and at a step portion of the region on which a test element for processing control formed inside of the dicing line or an alignment mark are formed, so as to completely cover the step portions. Since the conductive layer does not come off the step portions in subsequent steps, a short circuit of a wiring layer formed on a semiconductor chip region is prevented.

Wafer having a dicing area having a step region covered with a

A method of electromagnetically stirring molten metal in an unsolidified portion of a continuously cast strand by a magnetic field formed by applying alternating current to at least two exciting coils, the method comprising: supplying to one of the exciting coils a first alternating current of a frequency in the range of 1-60 Hz and to the other one of the exciting coils a second alternating current with a frequency difference in the range of 0.03-0.25 Hz from the first alternating current to form a varying composite magnetic field thereby to induce stirred movement of varying direction and intensity in the molten metal.

Method of electromagnetic stirring in continuous metal casting process

A semiconductor device with a circuit including a fuse wiring which comprises a step portion provided on a first insulating film which is provided on a substrate; a fuse wiring provided on the step portion via a second insulating film so that the central portion of the fuse wiring traverses the step portion; the central portion of the fuse wiring being positioned at a higher position than both the side portions thereof by a distance equal to the thickness of the step portion; and a third insulating film having a flat surface provided on the fuse wiring.

Semiconductor device

A redundant circuit of a semiconductor device comprises a fuse (73) for laser trimming to connect between aluminum interconnections (6). The fuse (73) has a two-layer structure comprising a first film (3a) of polysilicon and a second film (7a) formed on the film (3a) of metal silicide, the line width l.sub.0 of the first film (3a) being shorter than the line width l.sub.1 of the second layer (7a). In addition, a PSG film (4) is formed to cover the fuse (73), and the laser beam is irradiated on the PSG film (4) in disconnecting the fuse (73). Accordingly, the first film (3a) having a short line width is uniformly fused and expanded, the fuse (73) is uniformly disconnected, and an opening (10) formed after explosion and splash thereof becomes smaller.

Redundant circuit of semiconductor device and method of producing same

At least two exhaust holes are formed in an atomizing nozzle of an apparatus for spraying an air-water mist for cooling which is used in continuous metal casting. The respective spraying mist streams from the exhaust holes cross each other before they reach the surface of a cast strand and are diffused forwardly due to the influence of the kinetic energy which is directed in the spraying direction after they crossed, so that they sufficiently enter the region between the surfaces of guide rollers and cast strand, thereby directly spraying the air-water mist over almost the entire region of the surface of the cast strand. In addition, a header is disposed in parallel to the guide rollers and a plurality of water branching pipes are attached in line to the header in the longitudinal direction thereof. The inner diameter of these water branching pipes are set to be sequentially smaller toward the lower stage. The back pressures of the atomizing nozzles are reduced by causing pressure losses in the water branching pipes coupled to the atomizing nozzles, thereby spraying a uniform flow rate of the water from each water branching pipe.

Cooling mechanism for use in continuous metal casting

An exhaust hole is formed in an exhaust side wall of a mist atomizing nozzle of an apparatus for spraying the mist for cooling for and is used in continuous metal casting. An introduction inlet is provided in an introducing side wall on the side opposite the exhaust side wall at the height position different from that of the exhaust hole. An air-water mixture supply pipe is attached to the introduction inlet to communicate therewith. The air-water mixture of relatively large water droplets is formed and is introduced into the mist atomizing nozzle by that air-water mixture supply pipe. After the air-water mixture repeatedly collides in the mist atomizing nozzle, the large water droplets are made fine and are sequentially exhausted from the exhaust hole by being pressed by the supply pressure from the rear side.

Growing community of inventors

Hyogo, Japan

Hiroshi Takagi