JPH02228060A - Integrated circuit protective device and integrated circuit device equipped with this device - Google Patents

Abstract

PURPOSE:To enable an element to be protected from surge voltage by providing an equivalent series circuit for a plurality of varistor function elements between signal lines which are adjacent to each other among a plurality of signal lines, and electrically connecting the series connecting point of the varistor function elements to an earth line. CONSTITUTION:An equivalent series circuit 13 for a plurality of varistor function elements 13a and 13b is provided to each section between signal lines 16 which are adjacent to each other among a plurality of signal lines 16 which are electrically connected to an integrated circuit element 12, and the series connecting point of the varistor function elements 13a and 13b in the circuit 13 is connected electrically to an earth line 17. And even if synchronous surge component flows into the side of the integrated circuit element 12 through the signal line 16, this surge component flows to the earth line 17 through the varistor function elements 13a and 13b and the series connecting point of the elements. Hereby, the surge component is absorbed by each varistor function element 13a and 13b, and the integrated circuit element is never broken by the surge voltage.

Description

Detailed Description of the Invention [Purpose of the Invention (Industrial Field of Application) The present invention aims to prevent surge components flowing into an integrated circuit element through a signal line electrically connected to the element into an earth line. The present invention relates to an integrated circuit protection device that protects the element body from surge voltage by bypassing the device, and an integrated circuit device equipped with the device.

(Prior Art) In recent years, as LSIs (Large Scale Integrated Circuits) have become highly integrated, electrode patterns have become finer, and as a result, the withstand voltage of LSIs against surge voltages and the like tends to decrease. Especially MOS-
In the case of a high input impedance element such as an LSI, the gate insulating film is extremely thin, and dielectric breakdown occurs easily when a surge voltage such as static electricity is applied to the gate insulating film.

Therefore, conventionally, a varistor functional element has been used to protect the integrated circuit element from surge voltage. Here, the varistor functional element means a solid-state element whose resistance value changes significantly depending on the applied voltage and whose voltage-current characteristics exhibit non-linearity.

An example of a surge countermeasure for an integrated circuit element using this varistor functional element is the one described in Japanese Utility Model Application Laid-Open No. 63-79654.

As shown in FIG. 4, this is made up of an integrated circuit element (LSI chip) 2 mounted on a circuit board 1 with a thin film varistor. A plurality of lead-out electrodes 3 are formed on both edges of the substrate 1, and terminals of lead-out wires (bonding wires) 4 from the element body 2 are electrically connected to the lead-out electrodes 3. Further, this extraction electrode 3 is electrically connected to another circuit (not shown) via a signal line 6. A thin film varistor 5 is formed between each extraction electrode 3, and this varistor 5 absorbs surge components flowing into the element body 2 via the signal line 7.

(Problem to be Solved by the Invention) By the way, the surge components flowing into the element body 2 side through the signal lines 6 include those that are independent for each signal line 6 (asynchronous surge) and synchronized surge (synchronous surge) as shown in FIG. 5 and 8. Here, the asynchronous surge components independently flowing into each signal line 6 are easily absorbed by each varistor 5. However, in the case of a synchronized surge, both ends of each varistor 5 have the same potential and cannot be absorbed, so that the surge is eventually transmitted to the integrated circuit element 2.

Therefore, the present invention aims to eliminate the above-mentioned drawbacks, and its purpose is to bypass the synchronous surge component to the integrated circuit element side through the signal line by bypassing it to the integrated circuit element side. An object of the present invention is to provide an integrated circuit protection device capable of accurately protecting the body from surge voltage, and an integrated circuit device equipped with the device.

[Structure of the Invention] (Means for Solving the Problems) The first invention protects the integrated circuit element from surge voltage by bypassing the surge component flowing into the integrated circuit element through the signal line to the ground line. In the integrated circuit protection device, an equivalent series circuit of a plurality of varistor functional elements is provided between each of the signal lines adjacent to the plurality of signal line gables electrically connected to the integrated circuit element body, and A series connection point of the varistor functional elements in the circuit is electrically connected to the ground line.

A second invention is an integrated circuit device comprising an integrated circuit element mounted on an element mounting board on which a ground line is formed,
An integrated circuit protection device is formed on the element mounting board to protect the element from surge voltage by bypassing the surge component flowing into the signal line to the ground line, wherein the integrated circuit element is electrically connected to the integrated circuit element. An equivalent series circuit of a plurality of varistor functional elements is provided between the signal lines adjacent to the plurality of signal lines connected to the green tiles, and the series connection point of the varistor functional elements in the circuit is connected to the ground line. The integrated circuit protection device is configured by electrically connecting them.

(Effect) 1st. According to the second invention, even when a synchronous surge component flows into the integrated circuit element side through the signal line, this surge component flows to the ground line through the varistor functional element and the series connection point of the element. . Therefore, the surge component is absorbed by each varistor functional element, and the integrated circuit element is not destroyed by the surge voltage.

(Example) Hereinafter, the present invention will be specifically explained with reference to Examples.

FIG. 1 shows an integrated circuit device that is an embodiment of the present invention.

11 shows an element mounting board, and an integrated circuit element (chip) 12 is mounted approximately in the center of this board 11. As shown in FIG.

Further, on both opposing edges of this substrate 11, a substrate 1
A plurality of bonding terminals 1 are arranged along the longitudinal direction of 1.
0 are formed at equal intervals, and each bonding terminal 10 and a terminal of the integrated circuit element body 12 are electrically connected by a bonding wire 14. Furthermore, each of the bonding terminals 10 is electrically connected to a separate path (not shown) via a signal line 16. A plurality of equal number series circuits 13 of varistor functional elements are formed between adjacent signal lines among the plurality of signal lines 16 . In this embodiment, the equal series circuits 13 are connected to the first . It consists of second varistor functional elements 13a and 13b. Furthermore,
The first in each equivalent series circuit 13. A series connection point 15 of the second varistor functional elements 13a and 13b is electrically connected to an earth line 17 formed on the substrate 11.

An integrated circuit protection device according to claim 1 includes a series circuit 13 of equal numbers of the varistor function elements 13a and 13b.

Here, the term varistor functional element refers to a solid-state element whose resistance value changes significantly depending on the applied voltage and whose voltage-current characteristics exhibit non-linearity. These include diode varistors, typically ceramic varistors such as zinc oxide or strontium titanate varistors, and applied products such as surge absorbers and arresters.

And the first. Second varistor functional element 13a.

Although individual parts may be used as the elements 13b, in this embodiment, elements formed on the substrate 11 by thin film technology are used, as will be described in detail below.

FIG. 2 shows the varistor functional elements 13a and 13 in FIG.
It shows an example of the configuration of the equal series circuit 13 of b.
The figure shows a cross section taken along the line A--A in FIG.

A rectangular bonding terminal 10 is formed on an element mounting board 11 made of an electrically insulating member, and a lower electrode 20, 21 is formed extending from the bonding terminal 12 in the longitudinal direction of the board. And the lower electrodes 20 adjacent to each other
．． A varistor forming element body layer 22 is formed in a rectangular shape so as to cover the varistor forming element body layer 21, and an upper electrode 1 is formed on the upper surface of this varistor forming element body layer 22 so as to face the lower electrode 20.21.
9 is formed. This upper electrode 19 is electrically connected to the ground line 17 by a conductive pattern.

Here, the opposing portion of the lower electrode 20 and the upper electrode 19 (indicated by 23) allows the first varistor functional element 1 to
3a is formed, and similarly a lower electrode 21 and an upper electrode 1 are formed.
The portion facing 9 (indicated by 24) forms the second varistor functional element 13b.

In the above configuration, first. Second varistor functional element 1
Since the series connection point 15 of 3a and 13b is electrically connected to the earth line 17, this series connection point 15 is
It is always equal to the reference potential (for example, the potential of the ground (GND) terminal) of the surge component flowing into the integrated circuit element 12 side via the signal line 16. Does this mean that the surge component is independent for each signal line (see FIG. 4, 7)?

Or, it is irrelevant whether synchronization is achieved (see FIG. 5, FIG. 8). Therefore, the surge component flowing into the integrated circuit element 12 side via the signal line will damage the first varistor functional element 13a or the second varistor functional element 13b and the series connection point 15 of the element, regardless of whether it is synchronous or asynchronous. is bypassed to the ground line 17 via the ground line 17 and absorbed thereby. Therefore, the integrated circuit element 12 is not destroyed by the surge voltage.

Although one embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to the above embodiment, and various modifications can be made.

For example, in the above embodiment, the integrated circuit protection device is formed on the element mounting board 11, but the device may be formed inside the integrated circuit element 12.

[Effects of the Invention] As detailed above, according to the present invention, even when a synchronous surge component flows into the integrated circuit element through the signal line, the element can be bypassed by bypassing it to the ground line. It is possible to provide an integrated circuit protection device that can more accurately protect against surge voltage, and an integrated circuit device equipped with the device.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an apparatus according to an embodiment of the present invention, and FIG.
A plan view showing an example of the configuration of the main parts in the figure.
The sectional view taken along the line A-A in the figure, and FIGS. 4 and 5 are plan views of the conventional example. 11... Element mounting board, 12... Integrated circuit element, 1
3... Equivalent private room row circuit, 13a, 13b... Varistor functional element, 15... Series connection point of varistor functional element, Fig.

Claims (2)

[Claims] (1) In an integrated circuit protection device that protects an integrated circuit element from surge voltage by bypassing surge components flowing into the element through a signal line electrically connected to the element to the earth line, An equivalent series circuit of a plurality of varistor functional elements is provided between adjacent signal lines among the plurality of signal lines electrically connected to the integrated circuit element, and the varistor functional elements are connected in series in the circuit. An integrated circuit protection device, characterized in that a portion thereof is electrically connected to the ground line. (2) An integrated circuit device comprising an integrated circuit element mounted on an element mounting board on which a ground line is formed, the element being connected to the element side via a signal line electrically connected to the integrated circuit element. An integrated circuit protection device is formed on the element mounting board to protect the element from surge voltage by bypassing surge components flowing into the earth line to the ground line, the integrated circuit protection device being electrically connected to the integrated circuit element. An equivalent series circuit of a plurality of varistor functional elements is provided between adjacent signal lines among the plurality of signal lines, and a series connection point of the varistor functional elements in the circuit is electrically connected to the ground line. An integrated circuit device characterized in that the integrated circuit protection device is configured by: