JPH0269972A - Semiconductor integrated device - Google Patents

Abstract

PURPOSE:To make the electric characteristic of elements uniform and improve the performance of a circuit by installing dummy resister elements of the same structure as a resistor element group installed on a semiconductor substrate. CONSTITUTION:Resistor elements 21-26 of a resistance value R are arranged in the same direction and at the same intervals. The elements 21-23 are connected with each other in parallel and the element 24 is used independently. The elements 25 and 26 connected to no other element act as dummy resistors. A stopper 29 is arranged around all the elements 21-26 to stable the position of a substrate. Thereby the electric characteristic of the elements is made uniform to improve the accuracy of a circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of arranging elements on a semiconductor integrated device having a highly accurate analog circuit.

[Prior art] In analog circuits such as D/A conversion circuits and A/D conversion circuits, input impedance 43 (Z, ) and feedback impedance 44 of operational amplifiers, resistive elements, capacitive elements, etc.
For (Z2), a resistive element, a capacitive element, etc. are used, but for example, when constructing a triple amplifier circuit using a resistive element, Z2 = R Z, = R / 3 (3 connected in parallel), which is exactly the same. Prepare four resistive elements of the structure.

When implemented on a semiconductor integrated circuit, it is difficult to make the resistance values equal to % by using a resistor element whose length is % of a resistor element having a certain basic length. Therefore, as shown in FIG. 2, an attempt was made to realize an accurate resistance ratio by connecting in parallel elements having the same structure and arranged at the same spacing and in the same direction.

[Problems to be Solved by the Invention] However, even if the arrangement method shown in FIG. Due to the influence of peripheral circuits such as the well 38, there is a difference in the electrical characteristics of the elements 31, 34 and 32, 33, resulting in a problem that it is difficult to obtain an accurate resistance ratio.

Therefore, an object of the present invention is to solve the above-mentioned problems by making the electrical characteristics of elements the same through simple additional operations and realizing a more accurate analog circuit.

[Means for Solving the Problems] In order to solve the above problems, the semiconductor integrated device of the present invention has the following features:
For a resistive element group in which a plurality of resistive elements having the same or similar structure and the same size are arranged in a certain order on a semiconductor substrate, at least one end of the array is provided with the same or similar structure with the same rule as the arrangement rule of the resistive element group. The feature is that dummy resistance elements of the same size are provided.

[Function] In order to equalize the electrical characteristics of passive elements such as resistors and capacitors, even if they are arranged in the same regular arrangement, the patterns are arranged in a grid pattern, which causes diffraction of light when exposing the wafer. Due to phenomena such as the photosensitivity of the resist being different between the inside and outside of the array, and the progress of etching during the manufacturing process also being different between the inside and outside of the array, the electrical characteristics of passive elements located at the ends of the array may vary. There will be a difference. Therefore, the above problem can be avoided by providing dummy elements that are not actually used on the circuit at the ends of the array.

[Example] An embodiment of the present invention will be explained based on FIG.

The elements 21 to 26 are diffused resistance elements having the same structure and the same size, and are all arranged in the same direction and at the same interval (distance L), and have a resistance value R. Elements 21, 22, 23 are 3
This is connected in parallel and operates as Z, (=R/3). One element 24 is used and operates as Z2 (=R). Although the elements 25 and 26 have a resistance value R, they are not connected to other elements and operate as dummy resistors. However, the contacts are provided at the same position as other resistance elements. Furthermore, in order to stabilize the substrate potential, stoppers 29 are arranged around all the resistive elements so as to be at the same distance from all the resistive elements.

When an amplifier circuit is constructed using this arrangement method, the input voltage 41 (V IN) and the output voltage 42 are
The relationship between (Vout) is as follows. At this time, since the elements 21, 22, 23, 24 have dummy resistors 25, 26, the progress of etching during the manufacturing process and the depth and spread of diffusion are the same, and therefore the electrical characteristics are uniform. Z2 :Z+=3:1
-... (11) The accuracy of the resistance ratio is improved. Therefore, VOUT = 3 * V IN ・
...(12) The performance as an amplifier circuit is improved.

FIG. 4 shows another arrangement example of the dummy element group. If the chip area is to be increased, the accuracy of the resistance ratio can be further improved by arranging the dummy element groups 48 above, below, and to the left and right of the element group 49 to be used.

Also, in this example, elements 25 and 26 were used as dummy elements, but
Even if the elements 21 to 24 are used in a circuit system different from the circuit in which they are used, the uniformity of the characteristics of the elements 21 to 24 is not lost. In this way, when the characteristics of the elements 21 and 25 do not have to be precisely matched, the chip area is not wasted by the dummy elements 25 and 26.

FIG. 5 shows another arrangement example of the used element group and the dummy element group 51. The elements 52 to 55 and 56 to 59 to be used are arranged in two rows, and dummy elements 60.61.62.63 are arranged outside of the elements 52.55.56.59.

In the above embodiment, diffused resistance was explained as the resistance material.
A polysilicon resistor has a similar effect.

Furthermore, the configuration method of the present invention is applicable not only to resistive elements but also to capacitive elements, coils, transistors, and the like.

Another embodiment of the present invention will be described. FIG. 6 is a diagram of a ladder resistor D/A conversion circuit. The reference voltage 70 (V
IN) is extracted in eight stages as an output voltage 71 (VOIIT).

The operation will be explained in more detail. Elements 80 to 87 are resistance elements arranged according to the construction method of the present invention (the arrangement shown in FIG. 1 is expanded, and two of the 13 elements at both ends are used as dummy elements). 87 has a resistance value R, and two elements 84 to 86 are connected in series to have a resistance value 2R. Then, set the value of R to be at least 100 times thicker than the on-resistance of the transistor switches 76 to 78 and 88 to 90, and set a constant so that the on-resistance of the transistor switch can be ignored.Then, the digital signal 73 ~75°°H
°°, regardless of “L”, I++=Io +I+
o=2 Io =11... (13) ■, □=L
+IIl:2I+ =I2...(14)IIN=12+
I+□=2I2=IIN... (15) (However, element 81
The currents flowing through ~86 are Lo, III, III1, and F, respectively. , I-, I2. Also, the current flowing from signal 70 is IIN
) In other words, engineering. = i then I + = 21 ・
・ ・ (17) I2 = 4i
・ ・ ・ [18] From signal 70 to signal 7
The current Is flowing through 2 is I s=4 i *D7S+2
i *D74+ i D7a... (19) (For example, if the signal 75 is °°H°゛, D75=1
, “L” then D7. = φ) Therefore, the output voltage is determined by Is and the resistance element 80, and the output voltage is determined by the above formula (% formula %) Here, for example, if the resistance value of the element 86 becomes larger than the resistance value of the other elements, the digital data D72, D74, D t
The linearity of the output voltage characteristics with respect to 5 is poor. Therefore, by applying the arrangement method of the present invention, the resistance values of the elements 80 to 86 become uniform, and the performance as a D/A converter is improved.

[Effects of the Invention] When using a plurality of circuit elements such as resistors, capacitors, transistors, etc., the present invention can reduce the electricity of all the elements sandwiched between the dummy elements by a simple additional operation of providing a simple dummy element. It is possible to make the physical characteristics uniform and improve the performance of the circuit.

Furthermore, the present invention can be applied even if process technology changes, and has an extremely wide range of applications in realizing high-precision analog circuits.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of circuit elements according to the present invention, FIG. 2 is a conventional circuit element layout diagram, FIG. 3 is an amplifier circuit diagram, FIG. 4 is a dummy element layout diagram according to the present invention, and FIG. Another dummy element arrangement diagram according to the invention, FIG. 6, is a ladder resistance type D/A conversion circuit diagram. that's all

Claims (1)

[Claims] For a resistive element group in which a plurality of resistive elements of the same or similar structure and the same size are arranged in a fixed order on a semiconductor substrate, at least one end of the array is arranged with the same or similar arrangement rule as the resistive element group. A semiconductor integrated device characterized in that a dummy resistance element having a similar structure and the same size is provided.