Patents Assigned to STMicroelectronics
  • Patent number: 5872053
    Abstract: The contact opening through an insulating layer is formed having a straight sidewall portion and a bowl shaped sidewall portion. The bowl shaped sidewall portion is near the top of the insulation layer to provide an enlarged diameter of the contact opening at the top relative to the bottom. A conductive material is then formed in the contact opening in electrical contact with a lower conductive layer. The conductive material forms a plug having an enlarged head, such as a nail head or a flat heat screw shape. The enlarged head protects the silicon and a barrier layer, if present, within the contact from being etched by any subsequent anisotropic etches. Thus, when an electrical interconnection layer such as aluminum is formed overlying the contact plug, the plug acts as an etch stop to prevent etching of a barrier layer of the barrier layer within the contact opening.
    Type: Grant
    Filed: December 30, 1996
    Date of Patent: February 16, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: Gregory C. Smith
  • Patent number: 5869388
    Abstract: A method is provided for a planar surface of a semiconductor integrated circuit, and an integrated circuit formed according to the same. A gate electrode is formed over a substrate having source/drain regions adjacent to the gate electrode and in the substrate. A silicon dioxide layer is formed over the gate electrode and a portion of the substrate not covered by the gate electrode. A first phosphorous doped spin-on-glass layer is formed over the silicon dioxide layer, wherein the spin-on-glass is doped to a concentration sufficient to facilitate gettering of charge mobile ions. An opening is then formed in the spin-on-glass layer and the silicon dioxide layer exposing a portion of the source drain region.
    Type: Grant
    Filed: March 21, 1995
    Date of Patent: February 9, 1999
    Assignee: STMicroelectronics, Inc.
    Inventors: Tsiu Chiu Chan, Frank Randolph Bryant
  • Patent number: 5869175
    Abstract: A structure formed during processing of an integrated circuit. Two layers of photoresist are formed over a conductive layer to be patterned. The lower layer is thinner than the upper layer, and is dyed to have a lower transmittance. Both layers are used as a masking pattern for the underlying conductive layer.
    Type: Grant
    Filed: May 16, 1995
    Date of Patent: February 9, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: John C. Sardella
  • Patent number: 5869371
    Abstract: A VDMOS structure with an added n- doping component, and a LOCOS oxide self-aligned to it, at the surface extension of the drain. The additional shallow n- component permits the body diffusion to be heavier, and hence reduces the risk of latchup.
    Type: Grant
    Filed: November 3, 1995
    Date of Patent: February 9, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: Richard A. Blanchard
  • Patent number: 5869946
    Abstract: Methods and apparatuses are provided for use in driving a multiple-phase brushless motor. The methods and apparatuses include generating a slewed phase control signal for each phase of the motor. The slewed phase control signals are substantially proportional to a speed control signal during non-transitioning periods, and are slewed from one state to the next state over time during transitioning periods. The transitioning periods being associated with a commutation point. The slewed phase control signals are used to generate pulse width modulated (PWM) driving signals, for each phase of the motor. Thus, the shape of the resulting PWM driving signal will include additional PWM pulses during the transitioning period that provide for a trapezoidal shaping of the current supplied to each of the phase coils in the motor. The result is that torque ripple is reduced because the overall current applied to the motor and the torque resulting therefrom will tend to be more constant during commutation.
    Type: Grant
    Filed: February 27, 1997
    Date of Patent: February 9, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: Francesco Carobolante
  • Patent number: 5870330
    Abstract: An SRAM cell includes a pair of N channel transistors acting as inverting circuits, a pair of N channel transistors which perform the control function for the cell, and a pair of N channel thin film transistors in depletion mode with gate and source shorted to provide load devices for the N channel inverter transistors of the SRAM cell.
    Type: Grant
    Filed: December 27, 1996
    Date of Patent: February 9, 1999
    Assignee: STMicroelectronics, Inc.
    Inventors: Tsiu Chiu Chan, Loi N. Nguyen
  • Patent number: 5866998
    Abstract: A power-switched driver circuit for a disc drive that provides accurate back emf detection in PWM mode. In one embodiment, a power transistor is coupled between the low side drivers and ground. During the off time of a PWM cycle, all of the high side drivers are off and the current recirculates through two of the low side drivers. The power transistor is off. This disconnects the motor from ground and allows the voltage on the center tap of the motor to be about half of V.sub.cc, which allows the back emf of the motor to be detected during the off time using a conventional comparator as the back emf approaches a zero crossing. During the on time of a PWM cycle, the power transistor is on.In an alternative embodiment, a power transistor is coupled between the high side drivers and V.sub.cc. During the off time of a PWM cycle, all of the low side drivers are turned off and the current recirculates through two of the high side drivers. The power transistor is off, disconnecting the motor from V.sub.
    Type: Grant
    Filed: October 24, 1997
    Date of Patent: February 2, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: Paolo Menegoli
  • Patent number: 5866797
    Abstract: A liquid level sensor unit outputs a voltage value which corresponding to a measured liquid level to an improved anti-slosh circuit that provides a fast timing rate during the initial condition of the circuit and a slow timing rate during the normal operation of the circuit. The improved anti-slosh circuit further includes a low liquid level warning circuit and a power-on-reset circuit. The system timing rate can be externally controlled by connecting an RC circuit to the improved anti-slosh circuit. Customer defined reference level for low liquid warning is also possible. The entire circuit is included on a single, monolithic integrated circuit. An input pin receives the signal from the fuel tank. An output pin drives a liquid level gauge.
    Type: Grant
    Filed: December 31, 1996
    Date of Patent: February 2, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: David F. Swanson
  • Patent number: 5866461
    Abstract: A bipolar power transistor and a low voltage bipolar transistor are combined in an emitter switching or a semibridge configuration in an integrated structure. In a version with non-isolated components, the components of the structure are totally or partially superimposed on each other, partly in a first epitaxial layer and partly in a second epitaxial layer, and the low voltage bipolar transistor is situated above the emitter region of the bipolar power transistor which is thus a completely buried active structure. In a version with isolated components, there are two P+ regions in an N- epitaxial layer. The first P+ region constitutes the power transistor base and encloses the N+ emitter region of the power transistor. The second P+ region encloses two N+ regions and one P+ region, constituting the collector, emitter, and base regions respectively of the low voltage transistor.
    Type: Grant
    Filed: February 18, 1997
    Date of Patent: February 2, 1999
    Assignees: STMicroelectronics s.r.l., Consorzio Per La Ricerca Sulla Microelettronica Nel Mezzogiorno
    Inventors: Santo Puzzolo, Raffaele Zambrano, Mario Paparo
  • Patent number: 5864696
    Abstract: A circuit and method for varying the time of a write cycle. A variable timer circuit is provided coupled to a write simulation circuit. The write simulation circuit receives a signal from a start write sensing circuit indicating that data is being written to memory cells of the array. The write simulation circuit includes a memory cell replicate which replicates the time required for writing data to memory cells of the array. After the memory cell replicate has changed state, a signal is output via a switching circuit to the variable timer circuit for generation of a write termination signal. The memory cells are tested at various write cycle speeds by controlling the variable timer circuit. The variable timer circuit is set to terminate the write as quickly as possible after a successful write to the memory cells has been completed.
    Type: Grant
    Filed: January 19, 1996
    Date of Patent: January 26, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: David C. McClure
  • Patent number: 5861660
    Abstract: A semiconductor integrated-circuit die includes a substrate of semiconductor material that has an edge. A conductive layer is disposed on the substrate, and a first insulator layer is disposed between the said substrate and the conductive layer. A functional circuit is disposed in the die. A conductive path is disposed beneath the insulator layer and is coupled to the circuit, the conductive path having an end portion that is located substantially at the edge of the substrate. The wafer on which the die is disposed has one or more signal lines that run along the scribe lines of the wafer. Before the die is scribed from the wafer, the conductive path couples the circuit on the die to one of these signal lines. The end portion of the conductive path is formed when the die is scribed from the wafer.
    Type: Grant
    Filed: September 17, 1996
    Date of Patent: January 19, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: David C. McClure
  • Patent number: 5859511
    Abstract: A circuit for operating a polyphase DC motor, such as the type having a plurality of "Y" connected stator coils, has circuitry for charging the coils at a rate which will reduce EMI and other noise, while maintaining an acceptable charge rate. The gate of a selected high side driving transistor is charged at a relatively high rate during a ramping phase. During the ramping phase, the gates of the selected transistor is charged to a voltage near the voltage needed to form a channel in the transistor for conduction. After the ramping phase, the gates are charged at a lesser rate in order to control the rate of charging of the stator coils to prevent noise.
    Type: Grant
    Filed: September 27, 1996
    Date of Patent: January 12, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: Francesco Carobolante
  • Patent number: 5856696
    Abstract: A field-effect transistor structure is described having a monocrystalline silicon channel region which is epitaxially continuous with an underlying monocrystalline silicon body region. Polycrystalline silicon source and drain regions abut the channel region. The source and drain regions are electrically isolated from the underlying body region by a patterned dielectric layer, which may include a thick field oxide. A polycrystalline silicon gate is capacitively coupled with the channel region by a second dielectric layer. The gate may extend laterally to partly overlap the source and drain regions.
    Type: Grant
    Filed: March 12, 1997
    Date of Patent: January 5, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: Richard A. Blanchard
  • Patent number: 5856707
    Abstract: A method of forming vias in an interlevel dielectric structure of an integrated circuit, such that the aspect ratio of the vias is smaller than the aspect ratios of vias having a height equal to the thickness of the entire interlevel dielectric structure, and the integrated circuit formed according to such a method. Conductive elements are formed over an insulator. A first dielectric structure is formed over the conductive elements and over the insulator. The first dielectric structure contains a first dielectric, formed over the conductive elements and the insulator, and a planarizing dielectric, formed over the first dielectric to bulk fill the areas between the conductors. A thin layer of a second dielectric can be formed over the first dielectric and the planarization dielectric. Vias are patterned and etched in the first dielectric structure. The thickness of the first dielectric structure is such that the aspect ratios of the vias through it is close to, or less than, 1.
    Type: Grant
    Filed: November 4, 1996
    Date of Patent: January 5, 1999
    Assignee: STMicroelectronics, Inc.
    Inventor: John C. Sardella
  • Patent number: 5856233
    Abstract: A method is provided for forming a field programmable device of a semiconductor integrated circuit, and an integrated circuit formed according to the same. A first conductive layer is formed. A first, fusible, dielectric layer is formed over the first conductive layer. The dielectric layer is patterned and etched to form a plurality of dielectric regions exposing portions of the first conductive layer. A second dielectric layer is then formed over the dielectric regions and the exposed portions of the first conductive layer. A plurality of contact openings through the second dielectric layer are formed to expose portions of the first conductive layer and portions of the dielectric regions. A second conductive layer is then formed over the second dielectric layer and in the contact openings.
    Type: Grant
    Filed: May 3, 1995
    Date of Patent: January 5, 1999
    Assignee: STMicroelectronics, Inc.
    Inventors: Frank Randolph Bryant, Fusen E. Chen, Girish Anant Dixit
  • Patent number: 5854539
    Abstract: An electroluminescent lamp is driven by a driving circuit that can supply an approximately sinusoidal signal, a bi-directional sawtooth signal or a single-ended sawtooth signal. Switches selectively transfer energy from a battery to an inductor and then from the inductor to the lamp. In one embodiment, the lamp voltage is compared to a reference waveform, such as a sinusoid. The switches are activated responsive to the error between the lamp voltage and reference waveform to minimize the error. The lamp can thus be driven with a closer approximation of the reference waveform.
    Type: Grant
    Filed: August 26, 1997
    Date of Patent: December 29, 1998
    Assignee: StMicroelectronics, Inc.
    Inventors: Ermanno Pace, Giorgio Mariani, Alessandro Fasan
  • Patent number: 5852359
    Abstract: A voltage regulator with load pole stabilization is disclosed. The voltage regulator consists of an error amplifier, an integrator which includes a switched capacitor, a pass transistor, and a feedback circuit. In one embodiment, the integrator circuit includes an amplifier, a capacitor, and a switched capacitor which is driven by a voltage controlled oscillator. The voltage controlled oscillator changes its frequency of oscillation proportional to the output current. In another embodiment, the switched capacitor is driven by a current controlled oscillator whose frequency of oscillation is also proportional to the output current of the voltage regulator. When the output current demand is large, the controlled oscillators increase the frequency which decreases the effective resistance of the switched capacitor thereby changing the frequency of the zero to respond to the change in the load pole.
    Type: Grant
    Filed: July 8, 1997
    Date of Patent: December 22, 1998
    Assignee: STMicroelectronics, Inc.
    Inventors: Michael J. Callahan, Jr., William E. Edwards
  • Patent number: 5850452
    Abstract: The present invention concerns a method for the numerical scrambling by permutation of data bits in a programmable circuit comprising a control unit and at least one data bus (DBUS) to transmit data between the control unit and several memory circuits. It consists of having data on the bus either in a scrambled form or in an unscrambled form according to whether it is instructions data or not. And data in some of the memories is scrambled. The present invention also concerns a method for realising a permutation circuit.
    Type: Grant
    Filed: July 31, 1995
    Date of Patent: December 15, 1998
    Assignee: STMicroelectronics S.A.
    Inventors: Laurent Sourgen, Sylvie Wuidart
  • Patent number: 5850139
    Abstract: A voltage regulator with load pole stabilization is disclosed. An error amplifier has a non-inverting input receiving a reference voltage and an inverting input receiving a feedback voltage from the output of the voltage regulator. A gain stage has an input connected to the output of the error amplifier and an output connected to a pass transistor that provides current to a load. A variable impedance device such as a FET transistor configured as a variable resistor is connected between the input and output of the gain stage to provide variable zero to cancel the varying pole when the output current drawn by the load fluctuates. Consequently, the disclosed voltage regulator has high stability without a significant increase in power dissipation.
    Type: Grant
    Filed: February 28, 1997
    Date of Patent: December 15, 1998
    Assignee: STMicroelectronics, Inc.
    Inventor: William E. Edwards
  • Patent number: RE36026
    Abstract: A programmable device for storing digital video lines, being of a type intended for use in TV sets with digital frame scan features whereby a video line is sample coded in a digital signal, comprises at least one pair of memories each adapted to contain the code of one video line, and a bank of registers connected in series to one another and to each of the memories, at least one of the registers being fed, at its input terminals, with the digital signal to parallel the samples to be input to the memories.
    Type: Grant
    Filed: April 20, 1995
    Date of Patent: January 5, 1999
    Assignee: STMicroelectronics S.r.l.
    Inventors: Fabrizio Airoldi, Franco Cavallotti, Alessandro Cremonesi, Gian G. Rizzotto