JPH07211860A - Formation of capacitance - Google Patents

Abstract

PURPOSE:To constitute the composite capacitances having the accurate capacity ratio by dividing the capacitances with ranges in close proximity in a matrix as the constituent elements of the different composite capacitances, and using the capacitances. CONSTITUTION:Unit capacitances 1 of 36 pieces are formed as the two-dimensional square matrix of 6X6. At the wirings on both sides, three unit capacitances on each line on both sides are connected one after another. At the wiring provided between the lines, six unit capacitances at each line of both sides are connected alternately. For the connection indicated in A of a broken-like frame, 18 unit-capacitances are connected to (a) and (b) each. The capacity ratio of the two composite capacitances to be formed becomes 1:1. The composite capacitances having the accurate capacity ratio can be constituted by dividing the different composite capacitances in the ranges in close proximity in the matrix as the constituend elements of the different composite capacitances and using the capacitances.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming capacitance in LSI technology.

[0002]

2. Description of the Related Art Normally, when manufacturing an LSI, a
It comprises a step of designing using D, a step of reducing the circuit diagram to manufacture a mask, and a step of printing the pattern of the mask on a silicon wafer.

Conventionally, in the case of forming capacitances having different capacities in such LSI technology, a method of forming a plurality of unit capacitances and connecting a plurality of unit capacitances corresponding to the capacities to form a composite capacitance is generally used. It is used for. For example, in the case of forming a complex capacitance having twice the unit capacitance, a capacitance having an area in which two unit capacitances are connected is formed, and in the case of quadruple capacitance, a capacitance having an area four times the unit capacitance is formed. Form.

[0004]

However, in the above-mentioned conventional method, the size of the formed capacitance is different depending on the capacitance, and therefore when it is desired to arrange a large number of capacitances together, the capacitances themselves should be arranged. There is a problem that the wiring layout becomes complicated.

In order to solve such a problem, when forming a large number of capacitances, a large number of unit capacitances are arranged in a two-dimensional matrix in a square array, and a plurality of unit capacitances are connected to form a plurality of unit capacitances. Methods have been proposed for forming complex capacitances.

However, when the unit capacitances of a certain area on the matrix are collectively connected and used as a single composite capacitance when the composite capacitance is formed by the above method, the unit capacitance is divided into the areas on the matrix. If there is a variation due to, the variation directly affects the accuracy of the composite capacitance, and the capacitance ratio of the plurality of composite capacitances formed by connecting the unit capacitances on the same matrix may include an error.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and in a method of connecting a plurality of unit capacitances arranged as a two-dimensional matrix to form a composite capacitance, Even if there is variation in the capacity of the
An object of the present invention is to provide a capacitance forming method capable of reducing the influence of this variation on the capacitance ratio of the composite capacitance.

[0008]

In order to achieve the above-mentioned object, the capacitance forming method according to the present invention divides and uses unit capacitances in adjacent ranges in a matrix as components of different composite capacitances. Characterize.

[0009]

Embodiments of the capacitance forming method according to the present invention will be described below.

FIG. 1 is a circuit diagram of a capacitance on an LSI formed by the capacitance forming method of the first embodiment. In this example, 36 unit capacitances 1,
1, ... Are formed as a 6 × 6 two-dimensional square matrix. The single plane shape of the unit capacitances 1, 1 ... Is a chamfered square.

The wirings 2, 2, ... Are arranged in the column direction, which is the vertical direction in the figure, on both sides of the matrix and between each column. For the wiring on both ends, every other unit capacitance on both sides should be 3
The wiring provided between the columns alternately connects six unit capacitances of the columns on both sides of the wiring.

In the connection indicated by A in the broken line, 18 unit capacitances are connected to the terminals a and b, respectively,
The capacitance ratio of the two composite capacitances formed is 1: 1.
Becomes

If the wiring shown by B in the broken line is used instead of A, 12 unit capacitances are connected to the terminals c, d and e, respectively, and the capacitance ratio of the three composite capacitances formed is 1. It becomes: 1: 1.

In this figure, only the wiring connected to one terminal of the capacitance is shown. The other wiring is also connected in the same manner, but depending on the application, for example, when one end of a plurality of composite capacitances is held at a common potential, the other wiring may be common to all unit capacitances.

In the example of FIG. 1, the unit capacitances are connected so that the capacitance ratio of the formed composite capacitance is 1: 1, but they may be connected as 12:24 and 9:27, for example. However, there may be a unit capacitance that is not used by being connected as in 9:26.

As shown in FIG. 1, by using unit capacitances in adjacent ranges in a matrix distributed as components of different complex capacitances, even if the capacitances of the unit capacitances vary depending on the area, The influence of variations can be dispersed and reduced.

FIG. 2 shows the capacitance on the LSI formed by the capacitance forming method of the second embodiment.
In this example, unit capacitances 1, 1, ... Arranged as a 6 × 6 two-dimensional matrix are connected for each column in the vertical direction in the figure,
Configure adjacent columns as different complex capacitances,
Eighteen unit capacitances are respectively connected to terminals a and b to form two composite capacitances.

FIG. 3 shows the capacitance on the LSI formed by the capacitance forming method of the third embodiment.
In this example, unit capacitances 1, 1, ... Arranged as a 6 × 6 two-dimensional matrix are connected in a staircase pattern over a plurality of columns, and adjacent wirings are connected to different terminals a, b. Two composite capacitances are formed by connecting 18 unit capacitances each.

In each of the above three embodiments, the unit capacitances are arranged as a 6 × 6 matrix, but the number of arrangements is not limited to this, and 4 × 10, 10 × 8.
The present invention can be similarly applied to any size matrix.

[0020]

As described above, according to the present invention, the unit capacitances in the adjacent ranges in the matrix are
Even if the capacitance of the unit capacitance varies depending on the area, it is possible to reduce the influence by distributing and using it as the component of different complex capacitances, and it is possible to form a complex capacitance having an accurate capacitance ratio. it can.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a capacitance on an LSI formed by a capacitance forming method according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a capacitance on an LSI formed by a capacitance forming method according to a second embodiment.

FIG. 3 is a circuit diagram of a capacitance on an LSI formed by a capacitance forming method according to a third embodiment.

[Explanation of symbols]

 1 unit capacitance 2 wiring a, b terminals

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Makoto Yamamoto 3-5-18 Kitazawa, Setagaya-ku, Tokyo Takayama Building Takayamauchi Co., Ltd.

Claims (2)

[Claims] 1. A capacitance forming method for forming a plurality of unit capacitances of a predetermined shape as a two-dimensional matrix in an LSI, and connecting a plurality of the unit capacitances to form a plurality of composite capacitances, wherein the matrix capacitances are close to each other. The unit capacitance within the range,
A method for forming a capacitance, characterized by using the components as components of different complex capacitances. 2. The plane shape of the unit capacitance is
The method of claim 1, wherein the capacitance is a chamfered rectangle.