JPS63289841A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the generation of disconnection, electromigration, etc., by forming a high melting point metal film with an inclination on the contact hole wall in the direction of a first metal wiring. CONSTITUTION:A high melting point metal film 14 is buried in grooves formed on the side surface of a first metal wiring 11 in contact holes. On the side surface of the contact hole wall vertical to the first metal wiring 11 in the contact hole, the high melting point metal film 14 is left with an inclination. By anisotropic etching applying an etching gas having a large selection ratio between the high melting point metal film 14 and a second metal film 15, the second metal wiring 15 is formed so as to pass on the contact holes keeping a line width larger than or equal to the short side of the contact hole. Thereby, the wiring pitch is reduced, and the generation of disconnection, electromigration, etc., can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of connecting metal wires in a multilayer metal wire.

[Conventional technology]

Conventionally, in this type of connection method between metal wirings, the line width of the first metal wiring in the region where the contact hole is to be formed is set to be larger than the size of the contact hole to be formed.

A process of forming a contact hole thicker than a normal wiring part by an amount that includes a margin for misalignment of the metal plate in advance, and opening a contact hole in the first interlayer insulating film in that area by anisotropic etching, The process of exposing the wiring and the second metal wiring,
The bottom of the tank is formed, including the step of wiring the contact hole so as to maintain a margin for misalignment in advance and to completely cover the contact hole so that the line width is thicker than that of the normal wiring portion. was.

Below, the conventional manufacturing method is shown in Figures 2-] to 2(g).
Explain using. FIG. 2 is a plan view of the fly, and FIG.

(2nd prisoner), (d), (f) are comparative cross-sectional views taken along line A-A' in Fig. 2 (&), Fig. 2 (c)
, (e) and (g) are cross-sectional views taken along line BB' in FIG. 2(a).

As shown in Figure 2, etc.) and (c), the first metal wiring (
A film thickness of 5000 A) is used to form a pattern of photoresist #i23 at a predetermined position of the first interlayer insulating film 22 on the film 21 (usually at the end of the contact hole 25).

The end of the first metal wiring 21 is
It is necessary to have a margin of about 0.4 μm.

Next, as shown in FIGS. 2(d) and 2(e), the first interlayer insulating film (film thickness of approximately 500 OA) was etched by anisotropic etching.
22 to expose the first metal wiring 2.

Next, as shown in FIGS. 2(f) and 2(g), the second metal wiring <ytii, thickness of approximately 800 OA) 24 is inserted into the contact hole with a margin and completely covered. In the section, make the line @ thicker and form it. In this way, a plan view as shown in FIG. 2(a) is obtained.

[Problem that the invention seeks to solve]

In the conventional wiring connection method described above, the a1 contact hole must be formed above the first metal wiring 21. This is because, if the contact hole 24 protrudes from the first metal film a21, for example, without a metal fitting, a groove is formed on the side surface of the first metal wiring 21.
Coverage of the metal film 24 of i@2 becomes poor in the groove, and there is a possibility of disconnection. Therefore, the contact hole 24
In the area where the hole is to be drilled, the line width of the first metal film a21 is made wider than the contact hole by an amount that takes into account the misalignment of the metal fitting (usually α
4 μm).

In addition, in the case of the second metal film @24, which is wired so as to cover the contact hole 24, the first metal wire 21 in the contact hole may be exposed due to misalignment of the metal fitting. If the second metal film! When etching 24, the first metal film [21 is also etched at the same time, so the second metal film [21] is etched at the same time.
The line width of the metal wiring 24 also needs to be widened in consideration of the misalignment of the metal wire in the contact portion.

My friend, number one. The wiring pinch of the second metal film M21.24 was not shortened, increasing the area of the semiconductor integrated circuit device. In particular, in integrated circuits such as gate arrays and micro combinators, the wiring area increases the chip area.

(9) In the conventional method, the coverage of the second metal wiring at the step of the contact hole is poor, resulting in disconnection.

Or the probability of electromigration occurring is 6
Nineteen.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing a semiconductor device that solves the above-mentioned drawbacks and eliminates the risk of shortening of the wiring beach and the occurrence of N1 disconnection, electromigration, and the like.

[Means for solving problems]

The structure of the present invention is such that a first interlayer P3 edge plate 1- is formed on the patterned first metal wiring, and the first metal wiring is substantially the same as the first metal wiring.
t) rM hole by anisotropic etching process to lengthen the thick bottom and to form a contact hole having a large long side at a predetermined position on the first gold MA wiring. At the same time, a step of forming a predetermined depth in the interlayer insulating film of stripe 1 on the side surface of the first metal wiring and a low pressure CVD method are performed.
The process of growing a high melting point metal film thickly on a semiconductor substrate and anisotropic etching using an etching gas having a large selection ratio of the first metal film and the high melting point metal film of 1 &: By etching the entire surface of the S film.

At the same time, a high melting point metal film is buried in the T-groove formed on the side surface of the first metal wiring in the contact hole, and at the same time, a high melting point metal film is filled in the side surface of the contact hole wall perpendicular to the wiring direction of the first metal wiring in the contact hole. A step of leaving the high melting point metal film tube with a slope and etching all the slag and high melting point metal in the other flat part;
A process of irradiating a metal film on the semiconductor substrate, and a high melting point gold ms so that the second metal wiring is passed over the contact hole with N5ll@l having the same size or more as the short side of the contact hole.
and.

The second metal film is characterized in that it includes a step of forming by anisotropic etching using an etching gas having a large selectivity with respect to the second metal film.

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a plan view and a sectional view showing a method for manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 1 is a plan view of the interconnection connection portion manufactured in this embodiment, and FIG. 1 is a cross-sectional view showing the manufacturing method of this embodiment in the order of steps. As shown in FIGS. 1(b) and 1(c), metal wiring 11.@1 is placed on the semiconductor substrate. For example, aluminum wiring (film thickness: 5000 A'') is formed.

At the top of it is the first 1-monno-rim $12. For example, the bias sputter oxide film is formed to have approximately the same thickness as the first metal wiring 11 (
Approximately 500 OA) t-length zero order.

A photoresist 13 is applied, and the photoresist 13 is patterned to form contact holes at predetermined positions. The size of this Q1 contact hole in the long side direction is set to be larger than the first metal interconnect #11 by 0.2μ.

Next, as shown in FIGS. 1(d) and 1(e), the first glabella insulating film lit is etched to a predetermined depth of approximately 4 mm by anisotropic etching.
The upper part of the first metal wiring 11 is etched to 00OA.
At the same time that -g is allowed to come out, a groove is formed in the side surface of the first metal interconnection 11. First eyebrow insulation v! The depth of 12 grooves,
It is formed to be shallower than the thickness of the first metal wiring 11.

Furthermore, FIG. 1(f) 1. (g) K, as shown, reduced pressure CV
By method D, the high melting point metal film 14, for example, tungsten, is made to have a thickness less than (approximately three times the depth of It). At this time, in the wiring direction (A-A' cross section) of the second metal arrangement fi15, the width of the groove is narrow t, so the upper part of the high melting point metal film is almost flat with only a slight constriction remaining. .

On the other hand, in the cross section BB', since the contact hole is larger than the groove, the step of the contact hole is reflected, resulting in the following shape.

As shown in FIG. 1(h) and (i), the high melting point metal film 1
4t-1 Using a CFJ-based etching gas with a large selectivity between the first metal 11411 and the high melting point metal film 14.
,, The entire surface is etched by anisotropic etching, and the refractory metal 14 is buried in the groove on the side surface of the first metal wiring 11. At the same time, the wiring direction (B-8) of the first metal wiring 11 is etched.
'Cross section), high melting point gold M14 is used at the contact step.
A side wall is formed with an inclination. At this time, if the first metal wiring 11 is made of aluminum, even if the high melting point metal 14 is exposed during etching, the first metal wiring 11 will not be etched.

As shown in FIGS. 1(j) and 1(k), the second metal wiring 15, for example, aluminum (800 OA in film thickness), is made to have a bottom length over the entire surface, and then a predetermined photoresist is placed on the second metal wiring 15. After patterning into a pattern, a large selection ratio t-
Patterning is performed by t-anisotropic etching using a Ct-based etching gas.

At this time, even if the lIJ width of the second metal wire 15 passing over the contact hole is the same as the short side dimension of the contact hole, and some misalignment occurs, The contact stage is formed with a slope and a relatively high melting point metal ps1
4, the first metal arrangement %i14 is not exposed, and the exposed high melting point metal %i14 is not etched with Ct-based etching gas.
) is a plan view of the final construction 1 manufactured in this manner.

〔Effect of the invention〕

As explained above, in the present invention, since the high melting point metal film is formed with an inclination on the wall of the contact hole in the wiring direction of the first metal wiring, some amount of metallization is required when forming the second metal wiring. Even if misalignment occurs, only the high melting point metal film is exposed, and the first metal wiring in the contact hole is not exposed, so there is no need to make the width of the second wiring layer wider than the contact hole. , the contact area can also be wired with the same wiring width and wiring pitch as the normal wiring part, and furthermore, Vc
In the first metal wiring, there is no need to widen the line width of the contact hole in the contact hole forming part.1) There is an effect that wiring can be done with the same wiring width and wiring pitch as in the normal wiring part. be.

Also, in the present invention, in the wiring direction of the second metal wiring, the first metal wiring and the high melting point metal film embedded in the grooves on both sides of the first metal wiring are connected to the fa2 metal wiring. The area is large, and the resistance value of the interconnection connection can be made small. Since the contact area of the second metal wiring has good coverage, there is no need to worry about breakage or electromigration, and highly reliable connections between wirings are possible. There is an effect.

[Brief explanation of drawings]

FIG. 1 (aJ) shows a cross-sectional view of a semiconductor device manufactured by the method of manufacturing a semiconductor device according to an embodiment of the present invention, FIG. 1 (b), FIG. , Fig. 1(j) are both cut along the line A-A' in Fig. 1 et al.
The manufacturing method of the embodiment of the present invention is shown in the order of steps, including nine cross-sectional views, FIG. 1(c), FIG. 1(e), FIG.
i) and Figure 1 (translation) are respectively Figure 1 (b) and Figure 1 (
d) % Same process as Figure 1 (f), Figure 1, Figure 1 Q). Both are cross-sectional views taken along the line B-B' of Figure 6, Figure 2 (ml is manufactured using the conventional manufacturing method), Figure 2 (ml) , Figure 2(d), Figure 2(f)
) shows the conventional manufacturing method in the order of steps, and both are shown in Figure 1 (
The sectional view taken from the 7th position along line A-A' in a), Figure 2(c), Figure 2(e), Figure 2-) are similar to Figure 2(a).
b), Fig. 2(d), and Fig. 2(f) show the semiconductor substrate in the same process, all of which are plane views taken along the line BB' of Fig. 21 (ml). This is a diagram. 11.21 Old shaft first metal wiring, 12, 22...
...First interlayer insulating film, 13.23...Photoresist, 14...High melting point metal film, 15.24
...-Second metal wiring, 25...Contact hole. □heni slut

Claims (1)

[Claims] forming a first metal wiring on a semiconductor substrate; growing a first interlayer insulating film on the main surface of the first metal wiring to have a thickness substantially the same as that of the first metal wiring; and over the first metal wiring. A contact hole having a longer side larger than the line width of the first metal wiring is opened at a predetermined position of the first metal wiring by anisotropic etching. a step of forming a groove of a predetermined depth in an interlayer insulating film, a step of growing a high melting point metal film thickly on the semiconductor substrate by low pressure CVD, and a step of growing a high melting point metal film thickly on the semiconductor substrate; By etching the entire surface of the refractory metal film by anisotropic etching using an etching gas having a selectivity of At the same time as embedding the melting point metal film, the high melting point metal film is left with a slope on the side surface of the wall of the contact hole perpendicular to the wiring direction of the first metal wiring in the contact hole, and another flat part is buried. Then, a step of etching all the high-melting point metal, a step of growing a second metal film on the semiconductor substrate, and a step of growing the second metal film on the contact hole with a size equal to or larger than the short side of the contact hole. A semiconductor characterized by comprising a step of forming by anisotropic etching using an etching gas having a large selectivity between the high melting point metal film and the second metal film so as to pass through the semiconductor with a line width. Method of manufacturing the device.