JPH01112762A - Semiconductor device - Google Patents

Abstract

PURPOSE:To increase the surface area of resistance without changing its cross section and to increase heat capacity artificially by providing a metal layer which is connected only to an input protective resistance through an opening which reaches the input protective resistance, and operates as a radiating plate. CONSTITUTION:Polysilicon is accumulated on an SiO2 film 12 of a semiconductor substrate 11 then patterned to form a resistance 13 by a usual technique and then PSG is accumulated thereon to form a PSG film 14. The PSG film 14 is patterned to shape openings (holds) 14a, 14b, 14c. The holes 14a and 14b are made for connecting pattern of Al, and the hole 14c therebetween is for making a radiating plate 15 of Al. Connecting patterns 17a, 17b and the radiating plate 15 are formed by attaching Al entirely then patterning it. Finally, a cover film 16 is accumulated to form an input protective resistance.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a semiconductor device in which the input withstand voltage of a human power protection circuit is strengthened by improving the thermal diffusion of a resistor portion that is easily destroyed by heat in the input protection circuit. In a circuit, the purpose is to provide a semiconductor device that increases the surface area and pseudo-increases the heat capacity while maintaining the original cross-sectional area of the resistor. an insulating film formed on a substrate including the input protection resistor;
A semiconductor comprising an opening formed by patterning the insulating film and reaching the input protection resistor, and a metal layer connected only to the input protection resistor through the opening and functioning as a heat sink. Contains and constitutes a method for manufacturing the device.

[Industrial application field]

The present invention relates to a semiconductor device in which the input withstand voltage of an input protection circuit is strengthened by improving thermal diffusion of a resistive portion of the input protection circuit that is easily destroyed by heat.

[Conventional technology]

An input protection circuit for a semiconductor integrated circuit is shown in the circuit diagram of FIG. 3, in which 21 is an input pad, 22 is an input protection resistor, and 23 is a diode, and the input signal passes through the illustrated circuit to the internal circuit. This is input to the first stage buffer, and in the figure, the part to the left of the broken line is the input protection circuit, and the part to the right is the internal circuit. A diode 23 and a transistor 24 may be combined as shown at the bottom of the figure.

Such an input protection circuit protects the internal circuit from sudden transient voltages and currents (static electricity, when the power supply is 0N10FF) in the input bin connected to the input pad.

[Problem that the invention seeks to solve]

In the conventional input protection circuit described above, when a transient voltage or current is applied, it has been experienced that the input protection resistor 22 is first burnt out and destroyed like a fuse. Therefore, the voltage and current withstand voltage of the input bin becomes the same as the withstand voltage of the input protection resistor 22, and there is a problem that the main body of the input protection circuit configured by combining transistors and diodes is not fully utilized.

The reason why the input protection resistor 22 burns out is due to the heat generated when a transient current flows. This σ is the width, height, and length of the resistor.

Increasing the cross-sectional area (bXh) of the resistor increases the heat capacity and the breakdown voltage. However, the absolute value of the resistance becomes small, and when a sharp manual pulse is applied, the input protection resistor cannot sufficiently dampen it, and the input protection circuit is input to the internal circuit before the transistors and diodes operate, and the internal circuit is destroyed.

Although it is possible to increase the absolute value, the area of the input protection circuit increases, which becomes an obstacle to increasing the degree of integration of large-scale integrated circuits. As explained above, in order to increase the withstand voltage of the input protection circuit, the size of the resistance (absolute value of R)
It is necessary to increase the heat capacity or the cross-sectional area of the resistance without changing the current.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device in an input protection circuit for a semiconductor integrated circuit, in which the surface area of the resistor is increased while keeping the original cross-sectional area of the resistor unchanged, thereby increasing the heat capacity in a pseudo manner.

[Means for solving problems]

The above problem is caused by an input protection resistor connected to an input pad on a semiconductor substrate, an insulating film formed on the substrate including the input protection resistor, and the input protection resistor formed by patterning the insulating film. The present invention is solved by a semiconductor device characterized by comprising an opening that reaches the input protection resistor, and a metal layer that is connected only to the input protection resistor through the opening and acts as a heat sink.

[Effect]

The heat dissipation plate described above is connected to a polysilicon resistor with a hole in the insulating film filled with a hole that is easy to conduct heat.
Since the upper part of the resistor is expanding, the heat generated in the resistor is three-dimensionally diffused by the heat sink ^2, which increases the heat capacity of the resistor and prevents the input protection resistor from being destroyed by heat. The human power protection circuit operates normally, and the internal circuits are protected from sudden transient voltages and currents.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to illustrated embodiments.

FIGS. 1(a) and 1(b) are a cross-sectional view and a plan view of an embodiment of the present invention, in which 11 is a semiconductor substrate (for example, a silicon substrate);
12 is an insulating film (Sin, film), 13 is a resistor formed of polysilicon, 14 is an insulating film (for example, PSG film), 15 is an AN heat sink, 16 is a cover film of, for example, PSG, and
Among the patterns, the left connection pattern 17a is connected to the input pad, and the right connection pattern 17b is connected to a diode or a combination of a diode and a transistor that constitutes an input protection circuit placed in front of the internal circuit. Connected.

When a transient voltage or current is applied to the pad, the voltage or current is applied from the pad through the connection pattern 17a to the resistor 13, then through the connection pattern 17b to the diode or a combination of a diode and a transistor, and then to the internal circuit. Ru. At this time, the heat generated in the resistor 13 is diffused to the heat sink 15 formed in the shape of a chimney, and since the upper part of the heat sink 15 is expanding, the heat generated in the resistor is diffused three-dimensionally, and the resistor is destroyed. is prevented.

In addition to polysilicon, the resistor 13 is made of FP (P type diffusion I), PM (N type diffusion N), etc., and the heat sink 1
5 can be formed of a material with high thermal conductivity in addition to A2.

The steps of the method of the invention will now be described with reference to FIG.

Refer to FIG. 2(a): Polysilicon is deposited on the 5iOz film 12 of the semiconductor substrate 11, and it is patterned using a conventional technique to form the resistor 13, and PSG is deposited on it to form the PSG film 14. make.

See Figure 2, etc.: Next, the PSG film 14 is patterned to form openings (holes) 14.
a, 14b, and 14c are formed. Holes 14a and 14b
is for the Al connection pattern described later,
The hole 14c between the holes 14a and 14b is for making the heat sink 15 of i. Refer to FIG. 2(C): Depositing An on the entire surface and patterning it to form connection patterns 17a, 17b and heat sink 15.
Since this Affi is deposited and patterned as part of the semiconductor integrated circuit manufacturing process, the method of the present invention is carried out in the normal semiconductor integrated circuit manufacturing process and does not require any special process. do not have.

Finally, a cover film 16 is deposited to form the input protection resistor shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, the withstand voltage limit due to the resistor is improved, the input withstand voltage is improved, the above effects can be obtained with the same area as the conventional resistor, the process steps are not increased, and the cost is not affected. be.

[Brief explanation of the drawing]

FIG. 1 is a diagram of an embodiment of the present invention, in which (a) is a sectional view, FIG. 2 (a) to (C) are sectional views of steps in the embodiment of the present invention,
FIG. 3 is a diagram of the input protection circuit. In the figure, 11 is a semiconductor substrate, 12 is a SiO□ film, 13 is a resistor, 14 is a PSG film, 14a, 14b, and 14c are holes, 15 is a heat sink, 16 is a cover film, and 17a and 17b are connection patterns. . Patent Applicant Fujitsu Ltd. Representative Patent Attorney Akimoto Kuki) f! Meijo general process Megumenkuni Figure 2 11 Do! J single curtain pole 12 SiO2 film 14 PSG pus 14a, 14b, 14c missing 15 a spare ball 16

Claims (1)

[Claims] An input protection resistor (13) connected to an input pad on a semiconductor substrate (11), and an insulating film (14) formed on the substrate (11) including the input protection resistor (13). and an opening (14) reaching the input protection resistor (13) formed by patterning the insulating film.
a, 14b, 14c), and a heat sink connected only to the input protection resistor through the opening (
15) A semiconductor device characterized by comprising a metal layer acting as a metal layer.