JPH0251251A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To being the parasitic capacity and the resistance between a plurality of circuits and a substrate in accordance with each other by floating the ground lines of a plurality of circuits from a substrate ground and connecting the ground line of the other circuit than said plurality of circuits with the substrate ground. CONSTITUTION:Connecting the ground line of a circuit C, the other circuit than circuits A and B which are required to have the same characteristic, to a substrate ground at a ground point 20 and floating the ground lines of the circuits A and B, which are required to have the same characteristic, from the substrate ground, the ground of a signal leaking through a parasitic element is connected to the grounds of the circuits A and B in a low-impedance circuit outside the integrated circuit to make the effect of the parasitic element equal to the circuit A and the circuit B and no difference in characteristic between the circuits A and B is exhibited. Thereby the characteristics of a plurality of circuits are placed in accordance with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor integrated circuit in which a plurality of circuits requiring the same characteristics are provided on the same substrate.

[Conventional technology]

FIG. 4 is a plan view showing a conventional semiconductor integrated circuit of this type. In the figure, A and B indicate circuit blocks such as a mixer circuit, a high frequency amplification circuit, and a frequency discriminator circuit that are required to have the same characteristics. C is a control circuit that controls circuits A and B, or a circuit or circuit A that is not directly related to circuits A and B.

1 is a semiconductor integrated circuit consisting of these circuits A, B and another circuit C; 2, 3...8...10... 12・
...15...18.19 is a pointing bat.

20 is a ground point to the semiconductor substrate 1.

FIG. 5 is a sectional view of a semiconductor integrated circuit made of a bipolar integrated circuit showing an example of substrate grounding.
is the aluminum wiring to the substrate ground, 22 is the collector electrode aluminum wiring, 23 is the base electrode aluminum wiring, 24 is the emitter electrode aluminum wiring, 25 is the emitter layer, 26 is the base layer, 27 is the collector layer, 28 is floating Collector, 29 is a P-type substrate, 30 is an oxide film, 31 is a separation layer,
32 to 39 are parasitic capacitances, and 40.41 is a parasitic resistance.

Next, the reference of the 0 circuit B whose operation will be explained is earth potential or a certain fixed potential (Figure 5 shows the case of a P board, and shows the case where the board is set to the ground potential, but in the case of an N board, ), if this reference point is connected to the aluminum wiring $I21 to the board ground, a part of the current to the ground of circuit B will be transferred to the aluminum wiring 21° separation layer to the board ground. 31. It is drawn out through the board 29, and due to the resistance etc. in between, the board 29 floats from the ground and affects 1 circuit B through capacitive coupling, current/voltage leakage, etc., so 1 circuit A and circuit B are the same. However, in circuits that require precision, the characteristics do not strictly match, and this is a problem as the characteristics do not match.

[Problem to be solved by the invention]

Since the conventional semiconductor integrated circuit is configured as described above, when circuits A and B operate, these circuits A and B operate.

A part of the operation signal of B is transmitted to the substrate 2 as a leakage signal through parasitic elements such as parasitic capacitances 32 to 39 and parasitic resistances 40 and 41.
In this case, for example, if the ground of one of the circuits A and B is connected to the board 29, a leakage signal will pass through the above-mentioned parasitic element to the aluminum wiring 2 to the board ground.
1. The separation layer 31° is taken out to the outside through the substrate 29,
Since it is connected to the ground of the other of circuits A and B outside the integrated circuit, the potential of the circuit connected to the board ground increases due to the influence of parasitic elements, even if circuits A and B are the same circuit. There was a problem in that it was not possible to obtain the performance of

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a semiconductor integrated circuit that can match the characteristics of a plurality of circuits that are required to have the same characteristics.

[Means to solve the problem]

In the semiconductor integrated circuit according to the present invention, among a plurality of circuits provided on the same substrate that require the same characteristics and other circuits other than the plurality of circuits, the plurality of circuits have their ground lines floating from the substrate ground. , and other circuits have their ground lines connected to the board ground.

[Effect]

In the semiconductor integrated circuit according to the present invention, the ground lines of a plurality of circuits that require the same characteristics are floated from the substrate ground,
By connecting the ground lines of other circuits to the board ground, the influence from the board ground on multiple circuits having the same characteristics was equalized.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, parts corresponding to those in FIG. 4 showing the prior art described above are designated by the same reference numerals. In the semiconductor integrated circuit of this embodiment, a circuit A that requires the same characteristics,
The ground line of B is lifted from the board ground, and the ground line of circuit C other than these circuits A and B is connected to ground point 2.
0 and is connected to the board ground.

Next, the operation will be explained. As explained in the prior art section, when circuits A and B operate, a part of the signal is transferred to the substrate 29 through parasitic elements. By connecting the line to the board ground and floating the ground lines of circuits A and B, which require the same characteristics, from the board ground, the ground of the signal leaked through the parasitic element can be grounded by a low impedance circuit outside the integrated circuit. Since it is connected to the ground of circuit B, the influence of the five parasitic elements is the same on circuits A and B, and there is no difference in characteristics between circuits A and B.

Although Figure 1 describes only the basic method of grounding, as shown in Figure 2, circuit A and circuit B can be arranged symmetrically with respect to the plane perpendicular to Xl-X2 on the semiconductor chip. Then, the parasitic capacitance and resistance of circuit A and circuit B to the ground (substrate 29) become the same, and the characteristics of circuits A and B match more closely than in the case of FIG. 1. In this case, the directions of the diodes, resistors, and transistors constituting each of the circuits E to H in the circuits A and B are arranged and wired in substantially the same direction.

Although FIG. 2 shows an example in which the circuits A and B and the bonding pads are the same, FIG. 3 shows an example in which the circuits are shifted left and right with respect to Xl-X2 to make them plane symmetrical.

In the above embodiment, the number of circuits required to have the same characteristics is two, A and B, but of course the number may be three or more.

〔Effect of the invention〕

As described above, according to the present invention, the ground lines of a plurality of circuits whose characteristics are to be matched are floated from the board ground, and the ground lines of other circuits other than the plurality of circuits are connected to the board ground. With this configuration, it is possible to match the parasitic capacitance and resistance between the multiple circuits and the board,
It is possible to match the characteristics of the plurality of circuits that are trying to obtain the same characteristics.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a semiconductor integrated circuit according to an embodiment of the present invention, FIGS. 2 and 3 are plan views of semiconductor integrated circuits according to two other embodiments of the invention, and FIG. 4 is a plan view showing a conventional semiconductor integrated circuit. FIG. 5 is a plan view showing a conventional semiconductor integrated circuit, and FIG. 5 is a vertical cross-sectional view of a conventional semiconductor integrated circuit. 1 is a semiconductor integrated circuit, A and B are circuits that require the same characteristics, C is another circuit, 20 is a ground point, and 29 is a semiconductor substrate. Note that in Figure 5, the same reference numerals indicate the same or equivalent parts. E: 8th magazine in Yuuchi H: Rei Kuchi 90 Takumi 20 near intersection A: Circuit B 1st printing C: Ise's episode Soto

Claims (1)

[Claims] In a semiconductor integrated circuit in which a plurality of circuits that require the same characteristics and other circuits other than the plurality of circuits are provided on the same substrate, the plurality of circuits have their ground lines floating from the substrate ground, and A semiconductor integrated circuit characterized in that the ground line of the other circuit is connected to the substrate ground.