JPH0618253B2 - Semiconductor integrated circuit - Google Patents

Description

The present invention relates to a semiconductor integrated circuit, and more particularly to a semiconductor integrated circuit having a voltage dividing resistor circuit.

(B) Prior Art Generally, a semiconductor integrated circuit having a voltage dividing resistor circuit for obtaining a predetermined voltage by providing a plurality of voltage dividing resistors between a certain predetermined voltage line, for example, a 5V power source line and a 0V GND line. As a circuit, Japanese Patent Laid-Open No. 59-29857 and the like are listed.

Fig. 5 shows two resistors (5) between the power line ( _Vcc line) (51) and the ground line (GND line) (52).
3) and (54) are formed, and between the resistors (53) and (54),
FIG. 6 is a plan view of a semiconductor integrated circuit (55) having a voltage dividing circuit for extracting a predetermined voltage.

This semiconductor integrated circuit (55) has a P-type diffusion region (57) as shown by a chain line in an N-type epitaxial layer (56) laminated on a P-type semiconductor substrate. The diffusion region (57) has a structure like the equivalent circuit shown on the left side.

An insulating film such as a silicon oxide film is stacked on the diffusion region (57), and the insulating film is etched by a normal etching method,
The contact hole shown by X is formed. The first contact holes are formed at the upper and lower ends of the diffusion region (57), respectively.
(58) and a second contact hole (59) are formed, and the diffusion region is formed.
A third contact hole (60) is formed between (57).

The contact hole is formed on the first contact hole (58).
V electrically connected to the diffusion region (57) through (58)
_{A CC} line (51) is provided, and the second contact hole (59) is provided.
Above the diffusion region (5) through this contact hole (59).
A GND line (52) electrically connected to 7) is provided. Further, an extraction electrode (61) electrically connected to the diffusion region (57) through the contact hole (60) is provided on the third contact hole (60).

Therefore, the first contact hole (58) and the third contact hole (6
A resistor R ₁ is formed between 0), and a third contact hole is formed.
A resistance R ₂ is formed between the (60) and the second contact hole (59).

(C) Problems to be Solved by the Invention In the above-mentioned configuration, for example, if the resistors R ₁ and R ₂ are 2
When the ratio of 3 is required, there are times when this ratio fluctuates due to the manufacturing flow, and there are times when it is desired to set this ratio to, for example, 4 to 5 because of the circuit.

At this time, it is necessary to change the position of the third contact hole (60), and for this purpose, the third contact hole (60) is changed.
It was necessary to redesign at least the mask for forming the mask and the mask for forming the extraction electrode (61) formed on the contact hole (60).

(D) Means for Solving the Problems The present invention has been made in view of the above problems, and the extraction electrode (1
1) is the length of the diffusion region 6 except for a width that prevents short circuits with adjacent electrodes, such as the V _cc line (1), the GND line (2) and other extraction electrodes (11). The solution is to provide all along the vertical direction.

(E) Operation Explaining with reference to FIG. 1, the taken out electrode (11) is provided so as to extend from the V _cc line (1) to the GND line (2), and the adjacent electrode (in FIG. 1, the V _cc line) is provided. All are provided along the length direction of the diffusion region (6) except for the width (the region indicated by the arrows a and a) for preventing a short circuit between (1) and the GND line (2). The third contact hole (10) with the arrows a, b.
The design is completed simply by changing the direction.

That is, even if the position of the contact hole (10) is changed, the extraction electrode
The reason for (11) is that ohmic contact can be made at almost any position.

Specifically, when the contact hole (10) is moved in the direction of arrow a,
The resistance of R ₁ decreases and the resistance of R ₂ increases. Arrow b
Moving in the direction of becomes the opposite of the above. In both cases, the extraction electrode (11) can contact the diffusion region (6) in almost all regions.

(F) Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the first embodiment, and FIG. 2 shows A- in FIG.
It is sectional drawing in the A'line.

In this embodiment, as in the equivalent circuit shown on the left side of FIG.
The two resistors R ₁ and R ₂ are connected to a reference voltage (for example, V _CC line).
(1) is connected between the GND line (2) and a predetermined voltage is taken out between R ₁ and R ₂ .

As can be seen from FIG. 2, first, there is a P-type semiconductor substrate (3), and there is an N-type epitaxial layer (4) laminated on this semiconductor substrate (3). There is an N ⁺ type buried layer (5) layer between the epitaxial layer (4) and the semiconductor substrate (3). Further, the semiconductor substrate (3) from the surface of the epitaxial layer (4)
A P ⁺ -type isolation region reaching the area is formed, and an island is formed by this isolation region.

Next, there is a diffusion region (6) formed on the surface of the N-type epitaxial layer (4), which is indicated by a chain line, and other regions, such as transistors, diodes, resistors and capacitors, are not shown in the drawing. Yes, a circuit having a predetermined function is configured.

Subsequently, an insulating film such as a silicon oxide film (7) formed on the epitaxial layer (4), a first contact (8) and a second contact (8) formed by opening the insulating film (7) by an ordinary etching method. Contact
There are (9) and a third contact (10). Here, the contacts (8), (9), (10) are shown by cross marks, respectively. The first contact (8) is the first power supply line (1) that serves as a reference voltage.
And the diffusion region (6) are electrically connected to each other, and the first power supply line (1) is, for example, a V _CC line of 5V. The second contact (9) has a second
For electrically connecting the power source line (2) and the diffusion region (6), and the second power source line (2) is, for example, 0 V G
It is the ND line. Further, the third contact (10) is
Extraction electrode (11) for obtaining a predetermined voltage and the diffusion region
(6) is electrically connected.

Therefore, a resistance R ₁ is formed between the first contact (8) and the third contact (10), and the third contact (10) is formed.
A resistance R ₂ is formed between the second contact 9 and the second contact 9.

Finally, the extraction electrode (11) which is a feature of the present invention will be described in more detail. The extraction electrode (11) is provided on the diffusion region (6) provided between the first power supply line (1) and the second power supply line (2) and is adjacent to the electrode.
All are provided along the length direction of the diffusion region (6) except for the width that prevents short-circuiting with (1) and (2).

The width sufficient to prevent the short circuit is indicated by arrows A and B, and is a width capable of preventing the short circuit and the leak between the electrodes. Therefore, the extraction electrode (11) is connected to the first power line.
It is formed on most of the diffusion region (6) extending between (1) and the second power supply line (2).

Therefore, when adjusting the resistance value or the like, it is sufficient to change the position of the third contact (10) while leaving the extraction electrode (11) as it is, and to redesign only the mask for contact formation. By moving in the direction of arrow a, R ₁ decreases and R ₂ increases, and when moving in the direction of arrow b, the opposite occurs.

Next, a second embodiment will be described. FIG. 3 is a plan view,
FIG. 4 is a sectional view taken along the line AA ′ of FIG.

In this embodiment, as can be seen from the equivalent circuit diagram written in FIG. 3, the voltage dividing circuit has three low antibodies. Therefore, the number of the third contacts 10 is required to be one less than the number of resistors.

Third contact (10) formed on the V _cc line (1) side and third contact (10) formed on the GND line (2) side
Have electrodes (11) and (11) respectively taken out, and these taken-out electrodes are provided on the V _CC line except for the areas of arrows a, a and u which prevent short circuit with adjacent electrodes and leakage between electrodes. It is formed from (1) to the GND line (2).

Therefore, when moving in the direction of arrow a, R ₁ decreases and R ₂ increases. The opposite is true when moved in the direction of arrow b. When moving in the direction of arrow c, R ₂ decreases, R ₃ increases, and the direction of arrow d becomes the opposite.

Although the first and second embodiments have been described with the electrodes having a single layer structure, they can be implemented with a double layer structure. In other words, as the defeat density increases, crossing with other wiring occurs, so that at least one of the first power supply line (1), the second power supply line (2) and the extraction electrode (11) becomes the second power supply line (1). It may be formed in a layer. The first power supply line (1) is electrically connected to the epitaxial layer (4) to prevent transistor operation.

(G) Effect of the Invention As is clear from the above description, the number of contacts, which is one less than the number of resistors required for the voltage dividing circuit, is set to the first power line (1) and the second power line (2). ) Provided on the diffusion region (6) between the same number of extraction electrodes (11) as the number of the contacts.
By arranging in substantially the entire region of the diffusion region (6), the resistor can be adjusted by changing only the position of the contact.

Therefore, the design time can be greatly shortened because the user is sick only by redesigning the contact mask.

[Brief description of drawings]

1 is a plan view of the semiconductor integrated circuit of the present invention, FIG. 2 is a cross-sectional view taken along the line AA 'of FIG. 1, FIG. 3 is a plan view of the semiconductor integrated circuit of the present invention, and FIG. 3 is a sectional view taken along the line AA 'in FIG. 3, and FIG. 5 is a plan view of a conventional semiconductor integrated circuit.

Claims (3)

[Claims] 1. A diffusion region formed in a semiconductor substrate, an insulating film formed on the diffusion region, a first contact and a second contact formed at both ends of the diffusion region by opening the insulating film. Contact, a first power supply line electrically connected to the diffusion region via the first contact, and a second power supply line electrically connected to the diffusion region via the second contact. At least a power supply line, a third contact formed by one less than the number of dividing resistors formed in the diffusion region, and an extraction electrode electrically connected to the diffusion region via the contact are provided. In the semiconductor integrated circuit, the extraction electrode is provided on the diffusion region provided between the first power supply line and the second power supply line to prevent a short circuit with an adjacent electrode. A semiconductor integrated circuit characterized in that it is provided all along the length direction of the diffusion region except the width of the groove. 2. The semiconductor integrated circuit according to claim 1, wherein at least the first power supply line, the second power supply line, and the extraction electrode are formed on a first-layer insulating film. 3. The semiconductor integrated circuit according to claim 2, wherein at least the first power supply line, the second power supply line, and the extraction electrode are formed on a second-layer insulating film.