JPH027434A - Manufacture of semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To enhance the working accuracy of a line width of a minute aluminum wiring part by a method wherein a patterning process of an aluminum wiring part of an internal electronic circuit is controlled automatically by an electric means without a subjective judgment and an artificial judgment of an operator. CONSTITUTION:While a patterning operation of a pattern of an aluminum wiring part in an internal electronic circuit progresses, an electric connection between a contact 2a closest to an outer, edge and a check pattern 1 is first cut out of two contacts 2a, 2b formed on a diffusion layer 3. Then, also an electric connection between the pattern and the contact 2b at its inside is cut. Therefore, positional coordinates of contacts 2a to 2c are decided so as to correspond to individual line widths of an underetching operation, a proper etching operation and an overetching operation; then, it is possible to control a patterning process of the internal aluminum wiring part with good accuracy by using an electric means out of the following two: to find a change in a current value by applying an arbitrary voltage between two check pads 4; to detect a change in a voltage value while an arbitrary electric current flows.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of manufacturing a semiconductor integrated circuit device, and particularly to a patterning process of aluminum wiring at the semiconductor wafer stage.

[Conventional technology]

To manufacture a semiconductor integrated circuit device, normally more than a dozen patterning steps are repeated at the wafer stage to form active and passive devices in sequence, and in the final step, patterning is performed by aluminum evaporation and etching. As a result, aluminum wiring is formed to interconnect the respective elements. In the step of forming this aluminum wiring, it is most important to keep the line width within the standard, so a check element for this purpose is specially provided on the wafer to control the etching state of the aluminum vapor deposited film.

Figures 6(a) to (C) show aluminum wiring width check pattern diagrams of aluminum wiring width checking elements used in conventional manufacturing methods, and each shows a line proportional to the internal electronic circuit wiring pattern. Consists of a wide strip-shaped aluminum pattern. In this case, each aluminum pattern indirectly shows the etching status of the wiring pattern of the internal electronic circuit, so this aluminum pattern is
), if the check pattern 1a is shown, it means that the under-etching is still in progress, and if the check pattern 1a is shown as shown in FIG.
If the check pattern IC is displayed as shown in FIG. Therefore, the operator must visually check this check pattern using a microscope and manage the etching process so as to obtain the best check pattern 1b.

[Problem to be solved by the invention]

However, the high integration of semiconductor integrated circuit devices,
The demand for higher speeds has been accelerating in recent years, and the importance of microfabrication technology has become even more important. Therefore, it is necessary to rely on the visual inspection of workers to check the lithography process, and to avoid differences in the judgment criteria of individual workers. Conventional wiring width checking methods for aluminum wiring patterns, which are greatly affected by judgment errors and the like, cannot adequately respond to recent aluminum wiring microfabrication techniques that require extremely high accuracy.

In view of the above-mentioned circumstances, an object of the present invention is to provide a method for manufacturing a semiconductor integrated circuit device that includes a patterning process for fine aluminum wiring that is completely free from the effects of operator subjectivity or human error. .

[Means to solve the problem]

According to the present invention, a method for manufacturing a semiconductor integrated circuit device includes a method for manufacturing a semiconductor integrated circuit device, in which a rectangular low concentration diffusion layer is formed on a semiconductor wafer, at least one of the end portions and at least two of the central portions of the diffusion layer are formed.
A step of forming an aluminum wiring width check element having a contact array for electrically connecting two locations with the upper layer aluminum vapor deposition film at different coordinate positions, and a step of simultaneously patterning the aluminum vapor deposition film and internal electronic circuit aluminum wiring. Etch the low concentration diffusion layer to cover only one end region with the two contacts and the two contacts.
A step of forming a pair of aluminum wiring width check patterns with their tips facing each other to divide each region into two regions including a central portion having two contacts, and a line of the pair of aluminum wiring width check patterns. The check pattern line width is controlled to an appropriate width by detecting the progress of width reduction from the resistance change of the divided region in the low concentration diffusion layer due to the exposure order of the two contact arrays on the different coordinate positions. and a patterning process for internal electronic circuit aluminum wiring.

〔Example〕

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of the aluminum wiring width check element used in the present invention and one state pattern thereof.
According to this embodiment, the aluminum wiring width check element formed on the wafer by the manufacturing method of the present invention is a strip-shaped low concentration diffusion layer formed in the same process as the low concentration well region or the diffused resistor of the internal semiconductor element. 3, one coordinate position determined respectively in the central region of both ends of this strip-shaped low concentration diffusion layer 3, and a determined region 2 slightly below the central region.
A pair of contacts 2c, 2 that connect locations at different coordinate positions to the upper layer aluminum vapor deposition film (not shown), respectively.
d, 2a, and 2b.

Here, these coordinate positions are determined by the relative relationship with the position coordinates of the low concentration diffusion ffA3 on the wafer.Then, this aluminum evaporated film is etched at the same rate as the aluminum wiring pattern of the internal electronic circuit is formed. ,
- Pairs of aluminum wiring width check patterns 1 are successively formed so that one end faces each other on the low concentration diffusion layer 3, and each of the other ends has a check pad 4. At this time, one tip of the pair of aluminum wiring width check patterns 1 includes only one contact 2d,
In addition, three contacts 2a and 2b with the other tip remaining
, 2c, the region of the low concentration diffusion layer 3 is patterned to be divided into two parts. Therefore,
As the patterning of the aluminum wiring pattern of the internal electronic circuit progresses and the line width of the aluminum wiring width check pattern 1 also decreases, two patterns 2 with two different position coordinates are formed on the low concentration diffusion layer 3. two contacts 2a, 2
In b, the electrical connection between the contact 2a closest to the outer edge of the diffusion layer 3 and the check pattern 1 is first broken, and then the electrical connection between the contact 2b inside the contact 2a is also broken. It will become droopy.

Figure 1 shows how to check the width of a pair of aluminum wirings.
This pattern shows a state in which patterning of pattern 1 progresses, most of the outermost contact 2a is exposed, and the electrical connection with check pattern 1 is about to be cut off.

Therefore, if the positional coordinates of the contacts 2a, 2b and 2C are determined to correspond to the line widths of under-etching, proper etching and over-etching, then any voltage can be applied between the two check pads 4. Using one of the following electrical means: determining a change in current value, detecting a change in voltage value through an arbitrary current, or directly detecting a change in resistance value between two check pads 4. This makes it possible to precisely control the patterning process of internal aluminum wiring.

FIGS. 2(a) to 2(c) are process flow diagrams showing an embodiment of the present invention in which aluminum wiring is patterned using the aluminum wiring width checking element. According to this embodiment, first of all, FIG. 2(a) shows that there is under-etching, and since the amount of etching is insufficient, both contacts 2a and 2b cannot be checked for aluminum wiring width. It is in a state where it is electrically connected to pattern 1. Therefore, in this state, the pair of check pads 4
The resistance value R1 of the diagonally shaded portion of the low concentration diffusion layer 3 sandwiched between the contacts 2a and 2d is detected. Next, when the etching progresses and the contact 2a becomes open as shown in FIG. 2(b), the detected resistance value becomes the shaded resistance R2 of the low concentration diffusion layer 3 sandwiched between the contacts 2b and 2d, and the etching progresses further. Contact 2a as shown in Figure 2(C)
, 2b are all ovens) 2c, 2
The resistance value R3 in the shaded area sandwiched by d is detected. Therefore, if the positional coordinates of the two contacts 2a and 2b are properly set, including the tolerance range d for variations, it is possible to detect that the aluminum wiring has been patterned to the specified width when the resistance value R2 is obtained. If the resistance value is R1, it is still under-etched, and if it is R3, it is known that over-etching has occurred. As described above, according to the present invention, the progress of the aluminum wiring patterning process can be managed by external electrical detection means without manual intervention, and therefore a computer-based production control system can be easily constructed. This makes it possible to establish an extremely high-precision micro-aluminum wiring processing process that is free from human error.

Although one structural example of the aluminum wiring width checking element has been described above, it is also possible to use many modified structures in implementing the present invention.

3 to 5 are plan views showing various examples of modified structures of aluminum wiring width checking elements that can be used in the present invention and one state pattern thereof.

That is, in FIG. 3, a slit 5 is formed in the center of the low concentration diffusion layer 3.
, and contacts 2a, 2a' and 2b, 2b' are arranged line-symmetrically. In the case of this check element jIl#, the low concentration diffusion layer 3 appears to be two resistors connected in parallel due to the etching state. A suitable result can be obtained. Next, in the structural example of FIG. 4, the formation of the innermost contact 2C is omitted. In this case, both under-etch and proper-etch conditions are detected in the same manner as the others, but over-etch conditions are detected by opening the detection circuit.

Further, the structural example shown in FIG. 5 shows a case where a pair of facing aluminum wiring width check patterns and contact arrangement are made to be exactly the same pattern. According to this structural example, it is possible to double the detection efficiency.

〔Effect of the invention〕

As explained in detail above, according to the present invention, the patterning process of internal electronic circuit aluminum wiring can be automatically controlled by electrical means without depending on the operator's subjectivity or human judgment as in the past. The line width processing accuracy of aluminum wiring, which is becoming increasingly finer, can be significantly improved.

A process sequence diagram showing an embodiment of the present invention in the case of patterning aluminum wiring using a width check element, and FIGS. 3 to 5 show various modified structural examples of the aluminum wiring width check element that can be used in the present invention. FIGS. 6(a) to 6(C) are diagrams of aluminum wiring width check patterns of aluminum wiring width checking elements used in the conventional manufacturing method.

1...Pair of aluminum wiring width check patterns, 2a
, 2b, 2a, 2b', 2c, 2d---Contact, 3...Low concentration diffusion layer, 4...Check pad, 5...Slit.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the aluminum wiring width checking element used in the present invention and one of its state patterns, and FIGS. 1a - 1b (b) lc <C) Article

Claims (1)

[Claims] A contact arrangement is provided on a semiconductor wafer, electrically connecting one rectangular low-concentration diffusion layer and at least one of the ends and at least two locations of the central portion of the diffusion layer to an upper aluminum vapor deposited film at different coordinate positions, respectively. forming an aluminum wiring width check element comprising: a step of etching the aluminum vapor deposition film in a step simultaneously with patterning of the internal electronic circuit aluminum wiring to cover the low concentration diffusion layer in an end region having the one contact; a step of forming a pair of aluminum wiring width check patterns with their tips facing each other, which are divided into two regions each including a chisel and a central part having the two contacts; and a step of checking the width of the pair of aluminum wirings. - Detecting the progress of reduction in the line width of the pattern from resistance changes in the divided regions in the low concentration diffusion layer due to the exposure order of the two contact arrays on the different coordinate positions, and adjusting the line width of the check pattern appropriately. 1. A method of manufacturing a semiconductor integrated circuit device, comprising a step of patterning internal electronic circuit aluminum wiring, which comprises a step of controlling the width of the internal electronic circuit aluminum wiring.