JPS60224218A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form minute contact holes with a very small size not depending on performance of the exposure apparatus, by a method by which a resist pattern can be minutely patterned. CONSTITUTION:After a first film 16 which has selective etching ability against the insulating film 15 is formed on the film 15 being above a semiconductor substrate 11, the film 16 is patterned. Next, on the whole surface a second film 20 which has selective etching ability against the film 16 is formed, the second film 20 is etched so as to be left only on the sides of the film 16, and the insulating film 5 is etched by employing the first film 16 and the second film 20a, 20b being left as a mask. In this way, more minute contact holes can be formed as compared with prior arts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for manufacturing a semiconductor device in which the formation of contact holes is improved.

[Technical background of the invention]

Conventionally, it has been manufactured on a semiconductor substrate as shown in FIGS. 1(&) and (b), for example. First, a 1r type diffusion layer 2 is formed on the surface of a Pfi silicon substrate 10 by a well-known technique, and then an insulating film 3 is formed on the entire surface. Subsequently, a resist/mother turn 5 having an opening 4 in a portion corresponding to a portion of the diffusion layer 2 is formed on the insulating film 3 (as shown in FIG. 1(, )). Next, using this resist pattern 5 as a mask, the insulating film 3 is selectively removed by reactive ion etching (RIE) to form a contact hole 6 to manufacture a semiconductor device (as shown in FIG. 1(b)). .

[Problems with background technology]

However, according to the prior art, since the contact hole 6 is formed by selectively removing the insulating film 3 by RIE using the resist film and the turns 5 as a mask, the contact hole 6 is formed using the resist film and the turns 5 as they are. The size is 6°. Therefore, the size of the contact hole 6 depends on the A-turn size of the resist film lean 5, and when trying to obtain a fine contact hole 6, the limit is determined by how finely 74 turns of the lean mother turn 5 can be made. be done. However, the minimum limit image of the resist aperture of the exposure equipment is not always the minimum contact hole size.The minimum contact hole size is determined by the performance of the exposure equipment.Therefore, it is difficult to obtain the desired fine contact hole. There is a possibility that it will not be possible.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a semiconductor device that can obtain fine contact holes without making the contact hole size dependent on the performance of an exposure device.

[Summary of the invention]

The present invention includes a step of forming a first film having selective etching properties with respect to the insulating film on a semiconductor substrate via an insulating film, a step of turning this film, and a step of etching the first film over the entire surface. a step of etching the second film so that it remains only on the side wall of the first film; and etching the remaining second film and the first film. This method attempts to obtain fine contact holes by etching the insulating film using the film as a mask.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 2(a) to 2(h).

[1] First, a dirt electrode 13 made of polycrystalline silicon is formed on, for example, a P-type silicon substrate 11 via a dirt oxide film 12, and then an n-type impurity is introduced into the substrate 1 using the dirt electrode 13 as a mask. Then, a P-type diffusion layer 14 was formed. Next, a 1 μm thick interlayer insulating film was applied to the entire surface.
A CVD SIO film 15 was deposited (as shown in FIG. 2(a)).

Next, on this CVD5iO film 15, a molybdenum (Mo) film 1°6 with a thickness of 5000× was deposited as a first film. Thereafter, a resist film is deposited on this Mo film 16, and first openings 17m, I' are formed in the resist film corresponding to parts of the dirt electrode 13 and the diffusion layer 14 by photolithography. 1b was opened to form a resist lean 18 (as shown in FIG. 2(b)). Furthermore, using this resist/mother turn 18 as a mask, the Mo film 16 is selectively etched away by RIE to form a second opening 19a11.
9b (as shown in FIG. 2(C)).

[11] Next, after peeling off the resist f-turn 18 using oxygen plasma, an aluminum (At) film 20 with a thickness of 300K was deposited on the entire surface as a second film (see Fig. 2(d) ). Subsequently, this A/ film 20 is etched away by RIE, and the second film 20 of the Mo film 16 is removed by RIE.
Only on the inner wall of the openings 19m and 19b is a Teno 9-shaped k.
The l membranes 20a and 20b remained (Fig. 2(,)
(Illustrated). Next, using the remaining At films 20m, 20b and MO film 16 as masks, the CVD 810. Membrane 1
5 is selectively removed by RIE to form contact hole 2.
1 m, 21b was formed (as shown in FIG. 2(f)). After that, the remaining At films 20&, 20b and the Mo film 16
was etched and removed using a mixture of sulfuric acid and hydrogen peroxide (as shown in Figure 2). Furthermore, At is vapor-deposited on the entire surface and then turned to form contact holes 21&, 21b.
At electrode wirings 22a and 22b were formed to connect to the dirt electrode 13 and the diffusion layer 14, respectively, through the wafer, thereby manufacturing a semiconductor device (as shown in FIG. 2(h)).

Therefore, according to the present invention, the CV on the silicon substrate 11
D5iO, after forming a Mo film 16 on the film 15 and opening it using a resist nozzle turf 18, peeling off the resist nolene 18, depositing an At film 26'i;ji5', and depositing the A
The t film 2o is etched by RIE to form MoH
! A only on the inner walls of the second openings 19m and 19b of X16
The T films 20m and 20b are left, and then the remaining At
The films 20a, 20b and the MO film 16 are masked and
'In order to selectively remove the VD Sin film 15 by RIE, the At film is 20g compared to the conventional one.

Since 20b was used as part of the mask during etching,
CVD s of minute contact poles 21a and 21b
io, can be formed on the membrane 15.

The diameters of the contact holes 21* and 21b can be changed arbitrarily. This will be explained with reference to FIGS. 3(a) to 3(c) and FIGS. 4(a) to 4(a). Here, the former indicates the case where the At film is thin, and the latter indicates the case where the At film is thick. Note that the same members as those in the above embodiment will be described with the same reference numerals. That is, in the former case, first, as in the above embodiment, a thin At
A film 23 was formed (as shown in FIG. 3(a)). Next, this At film 23 is removed by RIE to remove the MO film 16.
The At film 23' was left only on the inner wall of the opening 19 (as shown in FIG. 3(b)). Next, the remaining At film 23
' and MO film 16 as a mask, CVD Sin, film 1
5 is removed by etching to form a contact hole 2 with a large diameter.
4 was formed to manufacture a semiconductor device (as shown in FIG. 3(c)). On the other hand, in the latter case, after forming a thick At film 25 on the entire surface (as shown in FIG. 4(a)), this is etched away by RIB so that it is applied only to the inner wall of the opening 19 of the MO film 16. The At film 25' remains (as shown in FIG. 4(b)), and C.
VDS 10. The film 15 was removed by etching and a contact hole 26 with a small diameter was formed to manufacture a semiconductor device (as shown in FIG. 4(c)). From the above, it is clear that the diameter of the contact hole 21 can be changed arbitrarily by changing the thickness of the At film 16.

In addition, in the above-mentioned example, M was used as the first coating.

Although an At film was used as the film and the second film, the first film may be CVD5iO.

Any material that has selective etching properties for the film and silicon substrate, CVD5iO for the second coating, and selective etching properties for the film, silicon substrate, and first coating may be used.

In the above embodiment, after removing the Mo film and the remaining tapered At film, At electrode wiring was formed in the contact hole of the CVD Sin film, but the present invention is not limited thereto. For example, as shown in FIG. 5, a silicon nitride film 31 is used as a first film in place of the Mo film, and a contact hole 21 is formed using this silicon nitride film 31 and the remaining At films 20 and 20b as a mask. , 21b, At is deposited and patterned on the entire surface including the remaining At films 20h, 20b and the silicon nitride film 31, and A/21b is formed.
, electrode wirings 32 m and 32 b may be formed.

According to this method, the step of removing the Mo film and the remaining At film can be omitted compared to the case of the above embodiment, and the disconnection at the contact holes 21m and 21b of the At electrode wirings 32m and 32b can be avoided compared to the conventional method. can be prevented. This disconnection will be explained with reference to FIGS. 6(a) and 6(b). That is, in the case of the conventional structure shown in Fig. 1, the structure shown in Fig. 6 (
As shown in a), in order to form the At electrode wiring 33 directly in the cut-out contact hole 6 of the insulation film 3, the At
A break 34 occurs in the electrode wiring 33. However, in the case of the semiconductor device of the present invention shown in FIG.
A tapered At film 20h is provided around the upper portions of 1a and 21b.
In order to perform the vapor deposition and nolining of At with the 20b remaining, as shown in FIG. 6(b), an unbroken A
A four-electrode wiring 32 can be formed.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide a method for manufacturing a semiconductor device that can form contact holes that are finer than conventional methods.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are cross-sectional views showing a conventional method for manufacturing a semiconductor device in the order of steps, and FIGS. 2(a) to (h) are sectional views showing a method for manufacturing a semiconductor device according to an embodiment of the present invention. 3(&) to (C) are cross-sectional views showing the method of manufacturing a semiconductor device according to the present invention in the order of steps when the At film is thin;
4(a) to 4(c) are cross-sectional views showing the manufacturing method of a semiconductor device according to the present invention in order of steps when the At film is thick, and FIG. 5 is a cross-sectional view of a semiconductor device according to another embodiment of the present invention. Figure, 6th
Figures (&) and (b) are cross-sectional views for explaining the presence or absence of breaks in the At electrode wiring in the contact holes of semiconductor devices according to the prior art and the present invention. 1 No... P-type silicon substrate, 12... Dirt oxide film, 13... Dirt electrode, 14... Diffusion layer, 15=
-CVD Sin, film, 16- Mo film (first film)
, 17m, 17b, 19th, 19b-opening section, 1 B
...Resist Turf, 20.20 m, 20b
. 23.23', 25.25' ・At film, 21a, 21
b. 24.26...Contact hole, 22IL122b
132&, 32b, 33... At electrode wiring, 31...
・Silicon nitride film, 34...broken. Applicant's agent Patent attorney Takehiko Suzue Figure 1 (a) (b) Figure 2 Figure 2 'r! '52 Figure 3 Figure 4

Claims (1)

[Scope of claims] forming a second coating having selective etching properties with respect to the coating; etching the second coating so that it remains only on the sidewalls of the first coating; and etching the remaining second coating. and a step of etching the insulating film using the first film as a mask. (2) After etching the insulating film, remaining second film and first film are etched. Claim 1, characterized in that the film is removed by etching, a layer of electrode wiring material is deposited on the entire surface, and then this is turned to form the electrode wiring.
A method for manufacturing a semiconductor device according to section 1. (3) After forming the contact hole, an electrode wiring material layer is deposited on the entire surface including the remaining second coating and the first coating, and this is further turned to form the electrode wiring. A method for manufacturing a semiconductor device according to claim 1. (4) The method for manufacturing a semiconductor device according to claim 1, characterized in that a Mo film is used as the first film and an Aj film is used as the second film. (5) The method for manufacturing a semiconductor device according to claim 3, characterized in that a silicon nitride film is used as the first film.