JPH0235731A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To completely prevent the generation of hillock, and improve productivity, utility and reliability by a method wherein, after a second conductor thin film of different kind and a CVD insulating film are stacked on a lamination film in which wiring is formed, these films are left as side walls on the wiring side surface by anisotropic etching. CONSTITUTION:In an oxide film 12 on a semiconductor substrate 11, a contact hole is formed, and aluminum silicon alloy 13 and titanium nitride 14 for wiring use are continuously sputtered; by using photoresist as a mask, this lamination film is subjected to dry etching of halogen system gas and to simultaneous patterning; after a second titanium nitride 15 is sputtered, a CVD oxide film 15 using SiH4 and O2 is stacked; the whole surface is anisotropically etched by dry etcher using CF4 or C2F6, and the titanium nitride 15 and the CVD oxide film 16 are left as side walls of the wiring patterned in the preceding process. In this case, although the the CVD oxide film 16 and the titanium nitride 15 are etched at the same time in the same chamber, the titanium oxide 15 on the side wall is covered with the side wall of the CVD oxide film 16, and surely left with excellent reproducibility.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a semiconductor device, particularly to a method for forming wiring.

[Prior Art] Conventionally, as shown in FIG. 2, in a wiring method for a miniaturized semiconductor device, a contact hole is formed in an oxide film 22 on a semiconductor substrate 21 on which a semiconductor element is J-heated, and a contact hole is formed for wiring. Aluminum alloy 23 has a thickness of 0.5 to 1.0 μm, and titanium nitride 24 has a thickness of 1 μm to prevent hillocks and halation.
Sputtering occurs to some extent (FIG. 2(a)). Next, using the photoresist 7 as a mask, the laminated film is dry etched and patterned, and then a second titanium nitride 25 is deposited to a thickness of 0.1 μm.
(Fig. 2 (h)). Next, the entire surface was etched with an anisotropic dry etcher using ay4 gas,
Titanium nitride 25 is left as a sidewall on the wiring patterned in the previous process to prevent lateral hillocks generated during the heat treatment in the post process from causing wiring leakage or voids in the first insulating film (Figure 2 (C)). ). Thereafter, an OVD insulating film is grown as an interlayer film or passivation film.

[Problems to be Solved by the Invention] However, in the prior art, the aluminum alloy has a steep side surface shape, which causes spatter and the second nitride film tongue 25.
The coverage is poor, and when performing anisotropic etching on the entire surface, 1. Not enough remains as a side wall that has the effect of suppressing hillocks, and its production control and reproducibility are extremely poor, making it difficult to put it into practical use and causing reliability problems.

However, the present invention solves these problems,
The purpose is to completely prevent hillocks l-1
It stably supplies fine wiring with high productivity, practicality, and reliability.

[Means for Solving the Problems] The method for manufacturing a semiconductor device of the present invention is a semiconductor device in which wiring made of aluminum or its alloy is provided on a semiconductor substrate on which a semiconductor element is formed, via an insulating film. , a step of successively forming at least aluminum or its alloy and a thin film of a different conductive material, a step of simultaneously patterning the laminated film to form wiring, and a step of laminating a second N film of a different conductive material and an OVD insulating film. , the second conductive material thin II and OV
The D insulating film is anisotropically etched to form the second layer on the side surface of the wiring.
The method is characterized in that it includes a step of removing the conductive film and the OVD insulating film from the sidewalls and leaving them on the sidewalls.

[Example 2] Hereinafter, the steps for implementing the present invention will be explained in detail based on FIG. 2-a%C.

Semiconductor substrate 11 on which semiconductor elements such as transistors and resistors are formed in integrated circuit manufacturing according to the safmicron rule
A funkkut hole is opened in the oxidized IFJI2 of F, and aluminum for wiring;
．． Subsequently, titanium nitride 14 is continuously sputtered to a thickness of about 0.1 μm (FIG. 1(a)). Next, using the photoresist 1- as a mask, the bond layer was dry-etched and buttered with a halogen gas such as C62 or BOt, and then a second titanium nitride layer 15 was deposited to a thickness of about 0.1 μm. After sputtering, the OVD oxide film 18 using 5LH4 and O7 is
A layer of 6 μm is layered (Fig. 2 (h)). Followed by OF.

Alternatively, the entire surface is anisotropically etched with a dry etcher using 02F, leaving titanium nitride 15 and OvD oxidation +i% 16 as side walls on the wiring patterned in the previous step (FIG. 6(C)). At this time, in the process of forming the side wall, the OVD oxidized pancreas 16 and the titanium nitride 15 are etched simultaneously in the same chamber, but the titanium nitride 15 on the side wall is etched by the CvD oxidized
16 side walls and remains reliably with good reproducibility. Thereafter, a PSA film and a plasma nitride film were grown as passivation films by OVD.

As another example, the present invention was applied to the lower layer wiring of a two-layer wiring structure using an aluminum alloy, but the [[I wall of titanium nitride can be left with good reproducibility, and the hillock resistance and migration effect are improved. Furthermore, the sidewalls of the OVD oxide film also had the effect of improving the flatness of interlayer films and upper layer interconnections formed in subsequent steps.

Titanium nitride was used for the hillock prevention film and l-, but this is also to prevent halation in photolithography, and is not limited to titanium nitride. It can also be applied to conductive materials. Further, the aluminum alloy wiring is not limited to aluminum-silicon, but may also be an alloy of copper, platinum, etc., or a mixture thereof, and the method of forming it is not limited to heating, non-heating, or with or without bias. Furthermore, it can also be applied when a barrier metal is placed under the wiring.

[Effects of the Invention] As described above, according to the present invention, it is possible to reliably cover at least the upper surface (ll1 side) of aluminum or its alloy wiring with a thin film of a different type of conductive material, thereby producing a fine semiconductor with high productivity and reliability. This will enable practical use and stable supply of the device.

[Brief explanation of the drawing]

FIGS. 1(α) to CC) are schematic cross-sectional views showing a wiring forming process according to an embodiment of the present invention. FIGS. 2(α) to 2(C) are schematic cross-sectional views showing a conventional wiring forming process. °ゝ・11.21・
... Semiconductor substrate 12.22 ... Oxide film 13.23 ... Aluminum alloy film 14.24
...Titanium nitride 15.25 --- Second fe titanium nitride 26
・・・・・・（CoV D oxide film or more

Claims (1)

[Claims] In a semiconductor device in which wiring made of aluminum or its alloy is provided on a semiconductor substrate on which a semiconductor element is formed via an insulating film, a step of continuously forming at least aluminum or its alloy and a thin film of a different conductive material; A step of simultaneously patterning the laminated film to form a wiring, a step of laminating a second thin film of a different type of conductive material and a CVD insulating film, and anisotropic etching of the second thin film of a conductive material and a CVD insulating film to form a side surface of the wiring. A method of manufacturing a semiconductor device, comprising the step of leaving the second conductive film and the CVD insulating film as side walls.