Patents by Inventor Tetsuo Tada

Tetsuo Tada has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5894172
    Abstract: A bare chip (1) is rectangular, and has a front surface (1a) on the center of which semiconductor elements are integrated and a back surface. Notches (2) are formed on a side of the bare chip (1) according to the kind of the semiconductor elements integrated on the bare chip (1). The notches (2) are oblong and extend through the bare chip (1) from the front surface (1a) to the back surface. For example, assuming that the notch (2) represents "1" and a portion without the notch (2) represents "0", one-bit information is obtained according to the presence or absence of the notch (2). When detection of several portions is made, binary information according to a detection result, i.e., information regarding the type of the bare chip (1), is obtained. For detection of the presence or absence of the notch (2), the bare chip (1) is irradiated with light, and then whether the light goes through the notch (2) or is intercepted by the bare chip (1) is detected.
    Type: Grant
    Filed: November 8, 1996
    Date of Patent: April 13, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masahiko Hyozo, Toshiyuki Tsujii, Tetsuo Tada, Hiroshi Noda, Ryouichi Takagi, Mikio Asai
  • Patent number: 5436559
    Abstract: A method of testing a semiconductor device operating according to predetermined testing information. An output signal of the semiconductor device is received through a signal transmission line and a reference voltage is generated in accordance with an expected logical level of the output signal. The reference voltage is compared with a voltage of the output signal thus received and a current flow is supplied to the signal transmission line in accordance with the result. A logical level of the output signal thus received is determined and a decision is made whether the semiconductor device operates correctly.
    Type: Grant
    Filed: August 23, 1993
    Date of Patent: July 25, 1995
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Ryoichi Takagi, Tetsuo Tada, Koji Tanaka
  • Patent number: 5266894
    Abstract: A semiconductor testing apparatus includes a comparator for receiving a signal output to a pin terminal of a semiconductor device under test through a transmission line and determining a logical level of the received signal. Semiconductor testing apparatus 1 further includes a current supply circuit for comparing a voltage of an input terminal of comparator with a reference voltage applied by reference voltage sources and supplying a current to transmission line. When a signal ringing on transmission line and a reflection with undershoot and overshoot at input terminal occur, current supply circuit supplies a current to transmission line in accordance with a relationship of magnitude between the voltage at input terminal and the reference voltage. The current supply to transmission line is made to inhibit the overshoot and undershoot of the signal. This allows comparator to carry out a functional testing and a measurement of DC/AC characteristics of a semiconductor device at precise timing and at high speed.
    Type: Grant
    Filed: December 11, 1991
    Date of Patent: November 30, 1993
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Ryoichi Takagi, Tetsuo Tada, Koji Tanaka
  • Patent number: 5055780
    Abstract: A test apparatus for a semiconductor device is provided to be used for testing, wafer by wafer, a semiconductor device formed on a semiconductor wafer. The test apparatus for a semiconductor device comprises a test head, a probe card and a selection circuit. The probe card has an insulating transparent base plate, and protruding parts are formed on the main surface of the base plate corresponding to electrode pads on a test object semiconductor wafer, and conductive layer forming a prober for the electrode pad is formed on the surface of each of these protruding parts. A wiring layer is formed on the surface opposite to the main surface. The wiring layer and the probers are connected electrically through the through holes provided on the base plate. A prober to be connected to the test head is switched electrically, which makes it possible to test a semiconductor device without moving the corresponding semiconductor wafer.
    Type: Grant
    Filed: February 5, 1990
    Date of Patent: October 8, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Ryouichi Takagi, Tetsuo Tada, Masanobu Kohara
  • Patent number: 5042148
    Abstract: A probing card for wafer testing has a plurality of probes arranged so as to correspond to and come in contact with a plurality of bonding pads of semiconductor devices fabricated on a semiconductor wafer. The probing card comprises a base plate, contact fingers and wiring sections. The base plate is formed of photosensitive glass. The base plate defines through holes extending from one of its main surfaces to the other. The contact fingers are formed as columnar elements filling the through holes and having a cross-sectional area decreasing from opposite ends to an intermediate position thereof. Each contact finger has one end thereof projecting from one of the main surfaces of the base plate. This projecting end of each contact finger at least defines a substantially planar end face. The wiring sections comprise conductive layers formed in a predetermined pattern on the other main surface of the base plate and connected respectively to the other ends of the contact fingers.
    Type: Grant
    Filed: October 23, 1990
    Date of Patent: August 27, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Tada, Ryouichi Takagi
  • Patent number: 4983908
    Abstract: A probing card for wafer testing has a plurality of probes arranged so as to correspond to and come in contact with a plurality of bonding pads of semiconductor devices fabricated on a semiconductor wafer. The probing card comprises a base plate, contact fingers and wiring sections. The base plate is formed of photosensitive glass. The base plate defines through holes extending from one of its main surfaces to the other. The contact fingers are formed as columnar elements filling the through holes and having a cross-sectional area decreasing from opposite ends to an intermediate position thereof. Each contact finger has one end thereof projecting from one of the main surfaces of the base plate. This projecting end of each contact finger at least defines a substantially planar end face. The wiring sections comprise conductive layers formed in a predetermined pattern on the other main surface of the base plate and connected respectively to the other ends of the contact fingers.
    Type: Grant
    Filed: March 30, 1990
    Date of Patent: January 8, 1991
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Tada, Ryouichi Takagi
  • Patent number: 4961052
    Abstract: A probing plate for wafer testing is provided with a plurality of probes arranged so as to correspond to a plurality of bonding pads of semiconductor devices fabricated on a semiconductor wafer. The probing plate has a base plate formed of an insulating material, such as a photosensitive glass, and has contact fingers each having a raised portion in the free end thereof, contact conductors respectively formed on the surfaces of the raised portions of the contact fingers so as to be brought into contact with the corresponding bonding pads, and wiring conductors formed in a predetermined pattern on the surface of the base plate so as to extend respectively from the contact conductors. The contact conductors and the wiring conductors are formed simultaneously by a photolithographic process. The contact fingers and the raised portions thereof are also formed by subjecting the base plate to a photolithographic process.
    Type: Grant
    Filed: July 17, 1989
    Date of Patent: October 2, 1990
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Tada, Ryoichi Takagi, Masanobu Kohara
  • Patent number: 4888715
    Abstract: A semiconductor test system comprises an expected value storage area for storing expected values of output data supplied from a semiconductor device under test, a memory device for storing output data directly supplied from the semiconductor device under test in the form of the identical code with that of the expected value storage area, and a comparator for comparing output data from the memory device directly with expected values from the expected value storage area without any conversion.
    Type: Grant
    Filed: November 19, 1985
    Date of Patent: December 19, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Tada, Hideo Matsui
  • Patent number: 4873686
    Abstract: In a test assist circuit for a semiconductor device, an address input selector (14a) is so switched that an external address signal is supplied to an address decoder (4) to address a memory circuit (3), while an input data selector (14b) is so switched that external input data is stored in an input data register (5), to be stored in addressed memory elements. Information of the most significant bit of the input data register is stored in an input data information storage area (16), and information of the least significant bit of the address decoder is stored in an address decoder information storage area (15). Data read from the memory circuit is stored in an output data register (6), to be outputted to a data output terminal (9) with the information stored in the address decoder information storage area and that stored in the input data information storage area respectively.
    Type: Grant
    Filed: January 11, 1988
    Date of Patent: October 10, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Tada, Tsuyoshi Yamada
  • Patent number: 4813043
    Abstract: A semiconductor test device including a function test algorithmic pattern generator which comprises: an ALU unit with shift-in function for conducting a predetermined arithmetical and logical operation against the base data or the output of an ALU output register; the ALU output register being designed to store the output of the ALU and output a function test algorithmic pattern; and a parity detection circuit which conducts a parity detection against an arbitrary group of bits of the ALU output register, and the detection output is input into a shift-in input of the ALU.
    Type: Grant
    Filed: February 20, 1987
    Date of Patent: March 14, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hideshi Maeno, Tetsuo Tada
  • Patent number: 4807229
    Abstract: A semiconductor device tester comprises a random data generator, an algorithmic data generator, and a serial data generator. The test data pattern of the data generators are selected and combined to produce test pattern data actually applied to a device under test. At least part of the test data pattern from the algorithmic data generator are applied to one of the random data generator and the serial data generator, which, responsive thereto, produces the random test pattern data or the serial test pattern data.
    Type: Grant
    Filed: May 18, 1987
    Date of Patent: February 21, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Tetsuo Tada
  • Patent number: 4801871
    Abstract: A connection of each of the terminals of a semiconductor device under test (DUT) with a test signal provided from a tester and a connection of each of the above stated terminals with a power supply system in the tester are selected in an arbitrary manner based on the serial data for designating connections provided from the tester.
    Type: Grant
    Filed: September 19, 1986
    Date of Patent: January 31, 1989
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Tada, Hideshi Maeno
  • Patent number: 4799009
    Abstract: A wafer testing device in which a plurality of wafers can be tested simultaneously significantly reducing the time required for testing each chip. A prober is provided which receives a wafer to be tested. A probe card is coupled to the prober having a window through which a plurality of semiconductor memory chips on the wafer are observable. A plurality of probes are coupled to the periphery of the window in such a manner that the probes can be brought into contact with bonding pads on the plurality of semiconductor memory chips. A tester is connected to the probes which is capable of simultaneously testing each of the plurality of chips.
    Type: Grant
    Filed: March 31, 1983
    Date of Patent: January 17, 1989
    Assignee: VLSI Technology Research Association
    Inventors: Tetsuo Tada, Keisuke Okada
  • Patent number: 4720671
    Abstract: A semiconductor device testing device for testing a semiconductor device having input/output terminals includes a dynamic load circuit provided for each of the input/output terminals of the semiconductor device and a comparator provided for each of the input/output terminals of the semiconductor device which compares the voltage value obtained at the input/output terminal with a predetermined value to detect whether the internal state of the semiconductor device is a high impedance state or not. The confirmation of the electrical connection between the semiconductor device and the testing device is thereby conducted by the dynamic load circuit and the comparator.
    Type: Grant
    Filed: July 31, 1985
    Date of Patent: January 19, 1988
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tetsuo Tada, Keiichi Sawada