Semiconductor apparatus including a protection circuit against electrostatic discharge

• US 5,442,217 A
• Filed: 11/26/1993
• Issued: 08/15/1995
• Est. Priority Date: 12/01/1992
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Mimoto, Toshio
• Primary Examiner(s): Jackson, Jerome
• Assistant Examiner(s): GUAY, JOHN FRANCIS
• Application Number:
  US08/157,483
• Time in Patent Office: 627 Days
• Field of Search: 257/360, 257/361, 257/362, 257/363, 257/546, 361/90, 361/91, 361/92, 361/111
• US Class Current: 257/361
• CPC Class Codes: H01L 27/0251 for MOS devices
• CPC Class Codes: H01L 27/0259 using bipolar transistors as protective elements
• CPC Class Codes: H01L 27/0266 using field effect transistors as protective elements

Abstract

A semiconductor apparatus includes multiple protection devices to protect against electrostatic discharge to an internal circuit contained in the semiconductor apparatus. The semiconductor apparatus includes plural terminals including a ground terminal, a substrate bias terminal, a power supply terminal, and an input/output signal terminal. Plural protection devices are connected between various ones of these terminals to provide the necessary discharge protection for a variety of discharge scenarios.

Claims

1. A semiconductor apparatus including a protection circuit against electrostatic discharge, comprising:

an internal circuit;

a terminal connected to the internal circuit;

a ground wiring for applying a ground voltage to the internal circuit;

a substrate bias wiring for applying a substrate bias voltage to a substrate in which the semiconductor apparatus is provided;

at least one power supply wiring for applying a voltage having a different polarity from the polarity of the substrate bias voltage relative to the ground voltage;

a first protection device against electrostatic discharge for allowing a breakdown current to flow in response to a voltage having at least a specified level, the protection device being connected between the substrate bias wiring and the ground wiring;

a plurality of second protection devices against electrostatic discharge for allowing a breakdown current to flow in response to a voltage having at least a specified level, the protection devices being respectively provided between the terminal and one of the ground wiring and the substrate bias wiring, and between the power supply wiring and one of the terminal, the ground wiring and the substrate bias wiring; and

a plurality of diodes respectively provided between the substrate bias wiring and the power supply wiring, between the substrate bias wiring and the terminal, and between the substrate bias wiring and the ground wiring, wherein the first and the plurality of second static electricity protection devices are each formed of a bipolar transistor.

2. A semiconductor apparatus including a protection circuit against electrostatic discharge, comprising:

an internal circuit;

a terminal connected to the internal circuit;

a ground wiring for applying a ground voltage to the internal circuit;

a substrate bias wiring for applying a substrate bias voltage to a substrate in which the semiconductor apparatus is provided;

at least one power supply wiring for applying a voltage having a different polarity from the polarity of the substrate bias voltage relative to the ground voltage;

a first protection device against electrostatic discharge for allowing a breakdown current to flow in response to a voltage having at least a specified level, the protection device being connected between the substrate bias wiring and the ground wiring;

a plurality of second protection devices against electrostatic discharge for allowing a breakdown current to flow in response to a voltage having at least a specified level, the protection devices being respectively provided between the terminal and one of the ground wiring and the substrate bias wiring, and between the power supply wiring and one of the terminal, the ground wiring and the substrate bias wiring; and

a plurality of diodes respectively provided between the substrate bias wiring and the power supply wiring, between the substrate bias wiring and the terminal, and between the substrate bias wiring and the ground wiring, wherein the first and the plurality of second protection devices are each formed of a MOS transistor.

3. A semiconductor apparatus for protecting an internal circuit from electrostatic discharge, the semiconductor device comprising:

a semiconductor substrate having a first conductivity (P);

at least one impurity diffusion region having the first conductivity provided in the semiconductor substrate;

a plurality of impurity diffusion regions each having a second conductivity provided in the semiconductor substrate;

a substrate bias wiring for electrically connecting the impurity diffusion region having the first conductivity and at least one of the plurality of impurity diffusion regions having the second conductivity, thereby applying a substrate bias potential to the semiconductor substrate;

a ground wiring electrically connected to at least one of the plurality of impurity diffusion regions having the second conductivity, thereby applying a ground potential to the internal circuit;

a terminal electrically connected to at least one of the plurality of impurity diffusion regions having the second conductivity, thereby connecting the impurity diffusion region electrically connected thereto to the internal circuit; and

at least one power supply wiring electrically connected to at least one of the plurality of impurity diffusion regions having the second conductivity, thereby applying a power supply potential to the internal circuit, wherein

the impurity diffusion region having the second conductivity electrically connected to the substrate bias wiring, the impurity diffusion region having the second conductivity electrically connected to the ground wiring, and a part of the semiconductor substrate form a first protection device against electrostatic discharge,

the impurity diffusion region having the second conductivity electrically connected to the terminal, the impurity diffusion region having the second conductivity electrically connected to the ground wiring, and a part of the semiconductor substrate form a second protection device against electrostatic discharge,

the impurity diffusion region having the second conductivity electrically connected to the power supply wiring, the impurity diffusion region having the second conductivity electrically connected to the ground wiring, and a part of the semiconductor substrate form a third protection device against electrostatic discharge, and

the impurity diffusion region electrically connected to the ground wiring and the semiconductor substrate form a diode, the impurity diffusion region electrically connected to the terminal and the semiconductor substrate form another diode, and the impurity diffusion region electrically connected to the power supply wiring and the semiconductor substrate form still another diode.