JPH08250589A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE: To increase the allowance of alignment of a contact hole with wiring without increasing the width of the wiring itself and without increasing the contact resistance. CONSTITUTION: A sidewall 28 made of a conductive film is formed on a wiring 25, with the wiring 25 and the sidewall 28 as stoppers, a contact hole 32 reaching the wiring 25 is opened in an SiO2 film 31. Thus, even if the misalignment with the wiring 25 occurs, the hole 32 is scarcely deepened from the surface of the wiring 25. Further, since the sidewall 28 is conductive, the contact resistance of the hole 31 is not increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device having a wiring in which a contact hole is to be opened.

[0002]

2. Description of the Related Art FIG. 2 shows a semiconductor device manufactured by a conventional example of the present invention. In this conventional example, Al-
The wiring such as the Si film 11 is formed of SiO ₂ as an interlayer insulating film.
The contact hole 13 for the Al-Si film 11 is covered with the film 12, and the contact hole 13 is opened in the SiO ₂ film 12.
An Al-Si film (not shown), which is an upper wiring layer to be connected to the Al-Si film 11 via the via, is formed.

However, when the width of the Al-Si film 11 and the dimension of the contact hole 13 are about the same, Al-S is used in the lithography process for opening the contact hole 13.
When the misalignment with respect to the i film 11 occurs, a part of the contact hole 13 becomes deeper than the surface of the Al—Si film 11 due to overetching, as shown in FIG.

As a result, the upper layer wiring, Al--Si
The reliability of the semiconductor device was low due to the occurrence of step breakage in the film and the formation of voids in the contact holes 13.
Therefore, the wiring is provided with an alignment margin in which the width of the portion of the lower layer wiring where the contact hole is to be opened is increased.

[0005]

However, if the wiring is provided with a contact hole alignment margin, the pitch of the wiring must be widened, and it is difficult to manufacture a highly integrated semiconductor device by the conventional method. Met.

[0006]

According to a first aspect of the present invention, there is provided a method of manufacturing a semiconductor device, wherein a side wall made of a conductive film is formed on a wiring, a step of covering the wiring and the side wall with an insulating film, the wiring and the side wall. And etching the insulating film using the side wall as a stopper to open a contact hole that reaches at least the wiring.

The method of manufacturing a semiconductor device according to a second aspect is characterized in that the wiring contains Al as a main component and the side wall contains a refractory metal as a main component.

[0008]

In the method of manufacturing a semiconductor device according to the first aspect of the present invention, the side wall that can be formed in self-alignment with the wiring is formed of a conductive film, and not only the wiring but also the side wall is used as a stopper to open the contact hole. Therefore, it is possible to increase the alignment margin of the contact hole with respect to the wiring without increasing the width of the wiring itself and increasing the contact resistance.

Further, since the wiring and the side wall are covered with the insulating film in the state where the side wall is formed on the wiring, the surface of the base of the insulating film is smoother than that in the case where the side wall is not formed on the wiring. It is easy to fill the stepped portion with an insulating film.

In the method of manufacturing a semiconductor device according to claim 2, A
Since the side wall containing a refractory metal as a main component is formed in the wiring containing l as a main component and continuity is maintained at the side wall even if the wiring is broken, overall electromigration resistance and stress of the wiring and the side wall are maintained. High migration resistance.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In this embodiment, as shown in FIG. 1A, a Ti film 21 having a film thickness of about 30 nm and a film thickness of 70 n are formed.
m TiN film 22 and Al having a film thickness of about 600 nm
-Si film 23 and TiN film 24 having a film thickness of about 100 nm
And are sequentially deposited by the sputtering method.

Then, a resist (not shown) having a wiring pattern is formed on the TiN film 24 by a lithographic method, and RIE using the resist as a mask is applied to the above film,
The wiring 25 is formed. Instead of the Al-Si film 23, an Al-Si-Cu film or the like may be used.

Next, as shown in FIG. 1B, the film thickness is 30
A TiN film 26 as an adhesion layer having a thickness of about nm is deposited by a sputtering method, and a W film 27 is further deposited by a CVD method.
Then, the entire surfaces of these films are etched back by RIE to form sidewalls 28 of the W film 27 and the TiN film 26 on the wiring 25.

Next, as shown in FIG. 1C, a SiO ₂ film 31 as an interlayer insulating film is formed on the entire surface, and the SiO ₂ film 3 is formed.
1. Contact hole pattern resist on top (not shown)
Are formed by a lithographic method. Then, RIE using the resist as a mask and the wirings 25 and the sidewalls 28 as stoppers is performed on the SiO ₂ film 31 to contact the contact holes 3
Open 2.

Next, as shown in FIG. 1D, the film thickness is 30
A TiN film 33 as an adhesion layer having a thickness of about nm is deposited by the sputtering method, and a W film 34 is further deposited by the CVD method.
Then, the entire surface of these films is etched back by RIE to form a plug 35 composed of the W film 34 and the TiN film 33 in the contact hole 32.

Then, a Ti film 3 having a film thickness of about 100 nm is formed.
6, an Al—Si film 37 having a film thickness of about 600 nm, and a TiN film 38 having a film thickness of about 100 nm are sequentially deposited by a sputtering method.

Then, a resist (not shown) having a wiring pattern is formed on the TiN film 38 by a lithographic method, and RIE using the resist as a mask is applied to the above film,
The wiring 41 on the upper layer side is formed. The Al-Si film 37
Alternatively, an Al-Si-Cu film or the like may be used. After that, although not shown, openings for the surface protection film and the boding pad are formed to complete the semiconductor device.

In the above embodiment, the contact hole 32
Since both the wiring 25 and the side wall 28 are used as stoppers at the time of opening, as is apparent from FIGS. 1C and 1D, even if misalignment with the wiring 25 occurs in the contact hole 32, the contact hole 32 remains. It is hard to be deeper than the surface of the wiring 25. Moreover, since the side wall 28 also has conductivity, the contact resistance in the contact hole 32 does not increase.

[0019]

According to the method of manufacturing a semiconductor device of claim 1,
Since it is possible to increase the alignment allowance of the contact hole with respect to the wiring without increasing the width of the wiring itself and increasing the contact resistance, the pitch of the wiring can be narrowed.
A highly integrated semiconductor device can be manufactured. Further, since the step portion between the wirings is easily filled with the insulating film, the semiconductor device can be manufactured by a simple process.

In the method of manufacturing a semiconductor device according to the second aspect of the present invention, since the wiring and the sidewall have high electromigration resistance and stress migration resistance as a whole, a highly reliable semiconductor device can be manufactured.

[Brief description of drawings]

FIG. 1 is a side sectional view of a semiconductor device showing an embodiment of the present invention in the order of steps.

FIG. 2 is a side sectional view of a semiconductor device manufactured by a conventional example of the invention of the present application.

[Explanation of symbols]

25 wiring 28 side wall 31 SiO ₂ film 32 contact hole

Claims (2)

[Claims] 1. At least a step of forming a side wall made of a conductive film on a wiring, a step of covering the wiring and the side wall with an insulating film, and etching the insulating film using the wiring and the side wall as stoppers. And a step of opening a contact hole reaching the wiring. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the wiring has Al as a main component, and the sidewall has a refractory metal as a main component.