JPS5863141A - Semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To manufacture the semiconductor integrated circuit device including output terminal with less resistance without sensing the resistance generated naturally by a method wherein the conductive line is provided between bonding pad of semiconductor integrated circuit element and external terminal making use of small metallic wire. CONSTITUTION:The overall semiconductor integrated circuit device including DC voltage stabilizing circuit is indicated by equivalent circuit in the diagram. As evident in the diagram, external terminal 3 leading output is connected to bonding pad 3' connecting to emitter of output transistor Q1 as well as to bonding pad 3'' connecting to input point of error amplifier A comprising detection transistor as usual to constitute the negative feedback circuit. Consequently the effect of resistance Rw in the conductive line becomes negligible while the output resistance may be reduced down to 10mOMEGA or less even if small metallic wire with diameter of 50mum or less is utilized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor integrated circuit device, and particularly to a semiconductor integrated circuit device that integrates a circuit section that uses negative feedback such as a DC voltage stabilization circuit to suppress the output resistance of an output terminal. It is.

In a semiconductor integrated circuit device that employs a circuit configuration that utilizes negative feedback for the purpose of keeping the output resistance of the output terminal low, and integrates this into a single semiconductor substrate, as far as the integrated circuit section is concerned, , the output generation point has a low impedance that can achieve the intended purpose. However, the current-carrying path from the bonding pad on the semiconductor substrate to the external lead-out terminal, which is essential when mounting a semiconductor integrated circuit device, is not included in the above-mentioned negative feedback path. Therefore, the resistance of the current carrying path, that is, the resistance of the thin metal wire connecting the bonding pad and the external lead-out terminal, and the resistance caused by the contact resistance between the bonding pad, the external lead-out terminal, and the thin metal wire. This is simply added to the output resistance up to the bonding pad on the semiconductor substrate, and there is a limit to lowering the output resistance at the output terminal led to the outside of the completed semiconductor integrated circuit device.

FIG. 1 shows the above content using an example of a DC voltage stabilizing circuit, and shows an equivalent circuit of the entire semiconductor integrated circuit device. The solid line frame indicates the entire semiconductor integrated circuit device, and the dashed line frame indicates the semiconductor integrated circuit element. In the figure, 1 to 3 indicate external terminals of the semiconductor integrated circuit device, and 1' to 3' indicate the semiconductor integrated circuit element. Further, Rw represents the resistance of the above-mentioned current-carrying path.

In this equivalent circuit diagram, the output resistance at the bonding pad portion 3', which is the output point of the semiconductor integrated circuit element, is defined as Z□, which is the output resistance at the emitter of the output transistor Q1 in the absence of feedback, and Set the loop gain to T
Then, it is expressed as Zo/T. Therefore, the output resistance ZOUT at the external terminal 3 where the output is generated is expressed by the following equation.

As is clear from the above equation, in order to reduce zoUT, the output resistance zO at the emitter of the output transistor Q1
Even if the loop gain T is made small and the loop gain T is made large, the resistance Rw of the current-carrying path remains.

According to the example of an actual DC voltage stabilization circuit, Z()=2
09. T = 80dB, RW = 5
It has a value of about 0 mΩ (Rw is the sum of the resistance of the Au wire itself with a wire diameter of 5 μm and the contact resistance caused by the connection between the Au wire and the bonding pad and external terminal),
When these are substituted into the first equation, the output resistance 2OUT becomes, and it is clear that the output resistance value is mostly determined by Rw. By the way, in DC voltage stabilization circuits, the output resistance of the output terminal is often required to have a value of several tens of mΩ or less. This requirement is met by using thin metal wires with a wire diameter of over 100 μm, but these thin metal wires are usually expensive A.
Since it is a U-ray, the cost of the semiconductor integrated circuit device increases, and as the wire diameter increases, it becomes necessary to increase the area of the bonding pad, resulting in the inconvenience of changing the element structure.

1 The present invention has been made with the intention of eliminating such problems, and in a semiconductor integrated circuit device in which the output resistance of the output terminal is kept low by using a negative feedback circuit, the output due to the resistance of the current carrying path is reduced. The present invention provides a semiconductor integrated circuit device having an output terminal with a low output resistance that is almost unrelated to an increase in resistance.

In the semiconductor integrated circuit device of the present invention, the bonding pad connected to the output electrode of the output transistor is connected to the external terminal from which the output is taken out by a first thin metal wire, and the bonding pad is further connected to the input electrode of the detection transistor. An output transistor and a first thin metal wire are fabricated in a semiconductor substrate by providing a pumping pad connected to the pad and connecting this pumping pad with a second thin metal wire.

A negative feedback path is constituted by an external terminal, a second thin metal wire, and a detection transistor implanted into the semiconductor substrate like the output transistor.

An embodiment of the present invention will be described by taking up a DC voltage stabilizing circuit in order to clearly compare it with a conventional example. Similar to FIG. 1, FIG. 2 shows an equivalent circuit of the entire semiconductor integrated circuit device including a DC voltage stabilizing circuit. As is clear from the figure, the external terminal 3 from which the output is taken out is connected to a bonding pad 3' connected to the emitter of the output transistor Q1, as in the conventional case, and is also connected to a bonding pad 3' connected to the input point of the error amplifier A consisting of a detection transistor. Ding pad 3'
is also connected to constitute the above-mentioned negative feedback circuit. As a result, the output resistance ZOUT of the external terminal 3 under such a circuit configuration is given by the following equation.

Compared to the circuit shown in FIG. 1, the influence of the resistance Rw of the current-carrying path on the output resistance ZoUT is 1 of the loop Caine. When the same numerical values as in equation (1) are substituted into the second equation, the difference is obvious. According to this example, ZOUT is almost determined by Zo and T, and the influence of the resistance RW of the current-carrying path is so small that it can be ignored. Further, an output resistance of 10 fflΩ or less can be achieved even when a thin metal wire with a wire diameter of 60 μm or less is used.

As is clear from the above explanation, according to the present invention, it is possible to take into account the resistance inevitably imparted by the thin metal wire that serves to provide a conductive path between the bonding pad of the semiconductor integrated circuit element and the external terminal. Therefore, it is possible to realize a semiconductor integrated circuit device having an output terminal with low output resistance.

[Brief explanation of drawings]

FIG. 1 is an equivalent circuit diagram of the entire conventional semiconductor integrated circuit device in which a DC voltage stabilization circuit is integrated, and FIG. 2 is a semiconductor integrated circuit device according to an embodiment of the present invention in which a DC voltage stabilization circuit is integrated. FIG. 2 is an overall equivalent circuit diagram. 1... External terminal for DC voltage stabilization circuit input, 1
'...Bonding pad for DC voltage stabilization circuit input, 2...Common external terminal, 2'...
・Ponding pad connected to common external terminal, 3...
...Output external terminal, 3'...Bonding "-1," connected to the output external terminal. Damn, 3'...Bonde connected to the input of the error amplifier... Resistance of conductive path. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] A bonding pad t connected to an output terminal of an output transistor built in the semiconductor integrated circuit board - connected to an output external lead terminal via the first conductive connection means, and also connected to the output terminal formed in the semiconductor integrated circuit board. A bonding pad connected to the input terminal of the detected transistor is provided, and the bonding pad is connected to the output external lead terminal via a second conductive connection means, and both the transistors, the first and second A semiconductor integrated circuit device characterized in that a negative feedback path including a conductive connection means and an external output terminal is formed to suppress the output resistance of the external output terminal to a low resistance value.