JPH08288396A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE: To realize a semiconductor integrated circuit enabling reliable and easy retrieval of a pad for measurement and prevention of an increase in area. CONSTITUTION: A pad 15 for electrical measurement is formed in a feedthrough cell region for wiring between wiring regions, on a wiring 14 of a feedthrough cell concretely, and the pad 15 for measurement and the feedthrough wiring 14 are connected electrically. According to this constitution, no increase in an area is brought about, the position of the pad for measurement is distinct and thus reliable and easy retrieval can be executed at the time of measurement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a layout design of a semiconductor integrated circuit, and more particularly to a cell structure for hierarchically forming a mask pattern.

[0002]

2. Description of the Related Art In order to facilitate so-called needle stand of a measuring terminal of a measuring device when performing electrical measurement after manufacturing a semiconductor integrated circuit, a measuring pad is provided on a needle stand at a design stage of the semiconductor integrated circuit. Is generally placed. In addition,
This measurement pad is formed of the same material as the wiring that is normally measured.

Generally, in the layout design of a semiconductor integrated circuit, a cell (hereinafter referred to as a feedthrough cell) for wiring between wiring regions (channels) is arranged and wiring is carried out through a cell row to increase the area. Also, the increase in wiring length is suppressed.

FIG. 9 shows an example of the structure of this feedthrough cell. As shown in FIG. 9, a power supply wiring 2 and a ground wiring 3, which are metal wirings for connecting to adjacent cells, are formed on both sides of the semiconductor substrate 1, which are opposed to each other. Feedthrough wiring 4 which is a metal wiring for connecting to the same potential wiring
Are formed to form a feedthrough cell.

Further, in automatic wiring, feed-through cells may be arranged between the cells in order to make the lengths of the cell rows uniform in order to prevent unnecessary wiring areas from being created. And
After wiring is completed, an empty area is used, a new area is secured and measurement pads are arranged, or a dedicated cell in which measurement pads are collected is made a part of a cell row. .

[0006]

However, when the measurement pads are arranged in the empty area of the wiring area, the measurement pads are scattered, which makes it difficult to perform a search during measurement. In addition, when the empty area cannot be sufficiently secured, there arises a problem that the measurement pad cannot be provided. Further, there is a drawback that the area of the integrated circuit increases if a dedicated cell in which pads are collected is used or a region for newly disposing a measurement pad is secured.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a semiconductor integrated circuit capable of reliably and easily retrieving a measurement pad and preventing an increase in area. .

[0008]

In order to achieve the above object, the present invention is a semiconductor integrated circuit provided with a measurement pad for performing electrical measurement, wherein the measurement pad is provided between wiring regions. Is formed in the cell region for wiring. Further, the measurement pad is formed on the cell wiring, and the measurement pad and the cell wiring are electrically connected.

[0009]

According to the semiconductor integrated circuit of the present invention, the measurement pad is not located in the wiring region for power supply or ground, but between the wiring regions as compared with the conventional case, the increase of the area and the increase of the wiring length are suppressed, or the length of the cell row is reduced. Since it is formed on the wiring of the cells provided for the purpose of equalizing the height, the area is prevented from increasing. In addition, the position of the measurement pad is clear, and it is possible to search reliably and easily during measurement. The function of the cell between the wiring regions is maintained as in the conventional case.

[0010]

1 is a diagram showing a cell structure showing an embodiment of a semiconductor integrated circuit according to the present invention, in which FIG. 1 (a) is a plan view and FIG. 1 (b) is XX of FIG. Sectional view on the line,
(C) is sectional drawing in the YY line of (a).

As shown in FIG. 1, the present cell has a power supply wiring 12 and a ground, which are metal wirings for connecting adjacent cells, on both sides of the semiconductor substrate 11 in the vicinity of the upper (front surface) side, which face each other. The wiring 13 is formed. Furthermore, a layer below the power supply wiring 12 and the ground wiring 13 (back surface)
The feedthrough cell is formed by forming the feedthrough wiring 14, which is a metal wiring for connecting to the same potential wiring in the wiring regions located on the upper side and the lower side, on the side. Then, a rectangular measurement pad 15 is formed in a layer above the feed-through wiring 14 (the same layer as the wirings 12 and 13 in the present embodiment), and the measurement pad 15 has a lower surface side and an upper surface side of the feed-through wiring 14. Are electrically connected via the contact 15a. Upper surface 1 of measurement pad 15
The substrate 11 on the 5b side has an opening 11a (without a pad window).
Is formed so that the measuring terminal of a measuring device (not shown) can be directly contacted during electrical measurement after manufacturing.

As described above, the measuring pad 15 according to the present embodiment suppresses an increase in area and an increase in wiring length between the two wiring regions rather than the wiring regions for power supply and ground as compared with the conventional case.
Alternatively, since it is formed on the wiring 14 of the feed-through cell provided for the purpose of aligning the lengths of the cell rows, the area is not increased, and the position is clear, and the measurement is performed. Sometimes the measuring pad can be retrieved reliably and easily and the function of the feedthrough cell is retained as before.

In the cell shown in FIG. 1, the measurement pad 15 and the feed-through wiring 14 are electrically connected via the contact 15a as an example. However, the measurement pad 15 and the feed-through wiring 14 are directly contacted with each other. Of course, it may be configured. Further, in the present embodiment, the power supply wiring 12 and the ground wiring 13
Although the case where the measurement pad 15 and the measurement pad 15 are in the same layer is shown as an example, the present invention is not limited to this. For example, as shown in FIG. 2 or FIG. It is also possible to connect the measurement pad 15 and the feedthrough wiring 14 by interposing the power supply wiring 12 or the ground wiring 13 as a layer between 15 and the feedthrough wiring 14.

Further, in the cells shown in FIGS. 1 to 3,
Although the opening portion (pad window opening) 11a is provided on the upper surface 15b side of the measurement pad 15, the pad window opening is not necessarily provided as shown in FIG.

Further, various cell structures are possible, for example, the following structure can be realized. That is, a cell having a plurality of feedthrough portions as shown in FIG. 5, a cell having a feedthrough portion provided on a measurement pad cell as shown in FIG. 6, a cell having a plurality of measurement pads on feedthrough wiring, and a feed The through wiring is not only a straight line but a cell having a bent wiring, a cell in which the wiring width is not constant and is changed midway, a measurement pad having a shape other than rectangular, for example, a cell formed in a circular shape or a triangular shape, or Various modes are possible, such as a cell in which a measurement pad is added on the feed-through cell separately from the cell hierarchy.

Next, the layout design of the semiconductor integrated circuit having the above-mentioned cell structure will be described step by step with reference to the drawings.

FIG. 7 is a block diagram showing a layout design system for a semiconductor integrated circuit according to the present invention. This system, as shown in FIG. 7, has a central processing unit (hereinafter,
In order to store the information of the graphic display device 22 for displaying the mask pattern, the keyboard device 23 for inputting various commands, the mouse device 24 for inputting commands on the graphic, and the CPU 21. A main storage device 25 and a magnetic disk device 26 for storing master data are connected to each other.

In such a structure, the mask pattern is usually designed by using cells divided into some unit, and data having a hierarchical structure is stored in the magnetic disk device 26. The stored mask pattern data is called by the CPU 21 and stored in the main storage device 25.
The layout design is completed by inputting a command from the keyboard device 23 and the mouse device 24 while looking at the mask pattern diagram that is read in and displayed on the graphic display device 22.

A layout design procedure using the automatic placement / wiring method will be described below with reference to the flowchart of FIG. First, similar to the mask pattern data, electrical cell connection information is fetched from the circuit diagram stored in the magnetic disk device 26, and cells necessary for the mask pattern configuration are generated (step S1). Then
Floor planning is performed to determine the arrangement position of the cells by predicting the connection state of the wiring between the cells and the electrical characteristics (step S2).

Next, cell placement conditions are input from the floorplanning result (step S3), and when a cell placement instruction is given, automatic cell placement processing is performed in consideration of the placement conditions (step S4). The arrangement result is a configuration in which several cells are arranged in one row (hereinafter referred to as cell row) and are arranged in several stages, and the wiring areas are provided between the upper and lower cell rows and the left and right cell rows.

Next, when wiring between wiring regions is required, a feedthrough cell as shown in FIG. 9 is inserted into the cell row so that wiring can be performed through the cell row in a later step (step S5). ). Then, it is confirmed whether or not the cell placement result is in a satisfactory state (step S6). If the arrangement conditions are not satisfied, the process returns to step S3 to perform the rearrangement.

If the arrangement conditions are satisfied, the wiring conditions are input from the cell arrangement result (step S7),
When the automatic wiring instruction is given, the automatic wiring process is performed in consideration of the wiring condition (step S8). As a result of automatic wiring, cells are wired using a predetermined wiring area. Then, it is confirmed whether or not the automatic wiring result is satisfactory (step S9). If the wiring condition is satisfied, the process is ended, and if the wiring condition is not satisfied, the process returns to the process of step S7 to perform the rewiring.

By the above steps, cell rows of several stages are arranged, inter-cell wiring is performed in the wiring region provided between the cell rows, and the mask pattern is completed. The connection of the wiring between the wiring regions is performed in step S5 by using the feedthrough cell arranged in the cell row.

As described above, according to this embodiment,
Since the measurement pads for electrical measurement are formed on the feed-through cell region for wiring between the wiring regions, specifically, on or within the feed-through cell, the area is increased. In addition, the position of the measurement pad 15 is clear, the search can be performed reliably and easily at the time of measurement, and the function of the feedthrough cell can be maintained as in the conventional case. Further, when this cell is prepared as several kinds of standard cells, there is an advantage that the shape change and the deletion work of the measurement pad can be easily performed by exchanging the cells.

In the above description of layout design,
The case where the automatic placement / wiring method is used has been described as an example, but the present invention is also applicable to the case where an arbitrary cell is used in the manual placement method and the manual wiring method.

[0026]

As described above, according to the present invention,
While maintaining the function of the feedthrough cell as before,
The area can be prevented from increasing. In addition, the position of the measurement pad is clear, and there is an advantage that the search can be performed reliably and easily during measurement.

[Brief description of drawings]

1A and 1B are diagrams showing a cell structure of an embodiment of a semiconductor integrated circuit according to the present invention, wherein FIG. 1A is a plan view, FIG. 1B is a sectional view taken along line XX of FIG. (C) is Y of (a)
It is sectional drawing in the -Y line.

FIG. 2 is a diagram showing another configuration example of the semiconductor integrated circuit according to the present invention, showing a configuration in which a power supply wiring or a ground wiring is interposed between a measurement pad and a feedthrough wiring.

FIG. 3 is a diagram showing another configuration example of the semiconductor integrated circuit according to the present invention, showing a configuration in which a power supply wiring or a ground wiring is interposed in a layer between a measurement pad and a feedthrough wiring.

FIG. 4 is a diagram showing another configuration example of the semiconductor integrated circuit according to the present invention, showing an example in which a pad window is not formed.

FIG. 5 is a diagram showing another configuration example of the semiconductor integrated circuit according to the present invention, which is a diagram showing a cell structure having a plurality of feedthrough portions.

FIG. 6 is a diagram showing another configuration example of the semiconductor integrated circuit according to the present invention, which is a diagram showing a cell structure in which a feedthrough portion is provided in a measurement pad cell.

FIG. 7 is a block diagram showing a layout design system for a semiconductor integrated circuit according to the present invention.

FIG. 8 is a flowchart for explaining a layout design procedure using the automatic placement / wiring method according to the present invention.

FIG. 9 is a diagram showing a configuration example of a feedthrough cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Semiconductor substrate 11a ... Opening (pad window opening) 12 ... Power supply wiring 13 ... Ground wiring 14, 14A-14C ... Feedthrough wiring 15, 15A-15C ... Measurement pad 21 ... Central processing unit (CPU) 22 ... Graphic display device 23 ... Keyboard device 24 ... Mouse device 25 ... Main memory device 26 ... Magnetic disk device

Claims (2)

[Claims] 1. A semiconductor integrated circuit having a measuring pad for performing electrical measurement, wherein the measuring pad is formed in a cell region for wiring between wiring regions. . 2. The semiconductor integrated circuit according to claim 1, wherein the measurement pad is formed on the cell wiring, and the measurement pad and the cell wiring are electrically connected.