JPH043461A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To obtain an accurate low resistance value, to reduce the occupying area of a chip, and to further obtain a desired partial pressure by dividing wirings by connecting a resistor having high accuracy and high area resistivity in parallel with a resistor having low area resistivity CONSTITUTION:One end of a resistor 1 is connected to one end of a resistor 3 by a wiring 2, the other end of the resistor 1 is connected to the other end of the resistor 3 by a wiring 2, and the resistors 1, 3 form resistors connected in parallel. Further, the resistor 1 has a structure which is disposed in parallel on the resistor 3. The resistor 1 disposed on the resistor 3 is divided by the wiring 2 to output a desired partial pressure from the resistor 1 having high accuracy resistance value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resistive element for a semiconductor integrated circuit, and more particularly to a resistive element formed of resistors having different sheet resistivities.

[Conventional technology]

Conventionally, a resistance element of a semiconductor integrated circuit is constructed using a thin film or a diffusion layer as a resistance material. Thin film resistors have a simple manufacturing process and are wired without using contacts. In addition, since the processing accuracy is good and the sheet resistivity is high, a highly accurate high resistance value can be obtained.

Diffused resistors have poor processing accuracy but low sheet resistivity, so a small chip area is sufficient in pattern design for low resistance where precision is not required. FIG. 1 is a diagram showing a resistance element of a semiconductor integrated circuit using a conventional thin film resistor, in which a first resistor 1 (thin film resistor) is directly connected to a wiring 2 without using a contact in the manufacturing process. There is.

In pattern design of semiconductor integrated circuits, resistance value R is calculated from resistance length p, resistance width W, and sheet resistivity ρS,
It is expressed by the following formula.

R = ρ, -... (1) As is clear from equation (1), if a resistance value R smaller than the sheet resistivity ρS is required, the resistance width W needs to be increased, The pattern design is as shown in FIG.

FIG. 2 shows that while the resistance width W of the first resistor 1 having a high sheet resistivity ρs1 is reduced, the sheet resistivity ρ is low.
2 is a diagram showing a conventional example in which a second resistor 3 (diffused resistor) having a resistor 2 is connected in parallel with the first resistor 1 to reduce the combined resistance value R. FIG.

FIG. 3 is an equivalent circuit diagram of FIG. 2. Here, if the resistance value of the first resistor 1 is R1, and the resistance value of the second resistor 3 is R2, then R+>R2 for boat fishing, so the desired resistance value R is R,>R2>R...(2) Obtained from the magnitude relationship.

[Problem to be solved by the invention]

In the conventional resistance element described above, when only the first resistor 1 is used, the area resistivity ρ31 is high, so in order to obtain a low resistance value with high accuracy, the resistance width W becomes large, which causes considerable problems in pattern design. Requires space.

Furthermore, even when the first resistor 1 and the second resistor 3 are connected in parallel to reduce the combined resistance value R, there is a drawback that more space is required in terms of pattern design.

The present invention uses a high-precision resistor with high sheet resistivity,
Provided is a resistive element for a semiconductor integrated circuit, which can reduce the area occupied by a chip in terms of pattern design, and can extract a desired partial voltage from the high-precision resistor.

[Means to solve the problem]

In the resistor element of the semiconductor integrated circuit of the present invention, the first resistor 1 having good precision but a high sheet resistivity ρs1 and the second resistor 3 having a low sheet resistivity ρs2 are connected in parallel, and the first resistor 1 is the second resistor 3
It has a structure placed on top of it.

〔Example〕

FIG. 4 shows an embodiment of the present invention. Said first resistor 1
One end of the first resistor 1 is connected to one end of the second resistor 3 by a wire 2, and the other end of the first resistor 1 is connected to the other end of the second resistor 3 by a wire 2. The resistor l and the second resistor 3 form a resistor connected in parallel. Furthermore, the first resistor 1 has a structure arranged above the second resistor 3 in parallel.

Further, by dividing the first resistor 1 disposed on the second resistor 3 using the wiring 2, a desired value can be obtained from the first resistor 1 having a highly accurate resistance value. Partial pressure can be taken out. FIG. 5 is an equivalent circuit diagram of FIG. 4.

〔Effect of the invention〕

As explained above, the present invention has good accuracy and connects the first resistor 1 having a high sheet resistivity ρs1 in parallel on the second resistor 3 having a low sheet resistivity ρ, 2. As a result, a highly accurate low resistance value can be obtained, and the area occupied by the chip can be reduced in terms of pattern design.

Further, by dividing the high-precision resistor by the wiring 2, a desired partial voltage can be obtained.

Further, if a thin film resistor is used as the first resistor 1, it is possible to improve the accuracy by laser trimming or the like, and there is also the effect that a highly accurate resistance value can be obtained.

A diagram showing the element, Figure 3 is an equivalent circuit diagram of the resistor element in Figure 2,
FIG. 4 is a diagram showing an embodiment according to the present invention, and FIG. 5 is an equivalent circuit diagram of the resistor element shown in FIG. 4.

■...First resistor, 2...Wiring, 3.
...Second resistor.

Agent: Patent Attorney Susumu Uchihara

[Brief explanation of drawings]

Figures 1 and 2 are resistance diagrams of conventional semiconductor integrated circuits. Figure 3 Figure 4 Figure 2 Figure 5

Claims (1)

[Claims] In a resistance element arranged in a semiconductor integrated circuit, a first resistor and a second resistor having different sheet resistivities are connected in parallel, and the first resistor is connected to the second resistor. A resistor element for a semiconductor integrated circuit that has a structure overlaid on a semiconductor integrated circuit.