JPH04356944A - Semiconductor device and its manufacture - Google Patents

Abstract

PURPOSE:To provide a semiconductor device and its manufacturing method wherein, when a contact hole is made in a layer insulating film and a wiring is formed of an Al alloy film, it is possible to restrain that impurities of baron, phosphorus or the like in the layer insulating film are diffused to the Al alloy layer or an Si substrate. CONSTITUTION:A first SiO2 film 9, a first SiN film 10 and an SiO2 film 11 which contains boron or phosphorus are grown on an Si substrate 8 in this order. This assembly is heat-treated; after that, a second SiN film 12 is grown on the SiO2 film 11. A layer insulating film composed of four layers is formed. Then, the layer insulating film is dry-etched via a resist pattern 13; a contact hole is formed; the resist pattern 13 is removed; after that a third SiN film 14 and a second SiO2 film 15 are grown sequentially; an anisotropic etching operation is executed; a sidewall insulating film by the third SiN film 14 and the second SiO2 film 15 is formed on the sidewall of the contact hole. Lastly, an Al alloy film 16 is vapor-deposited; the Al alloy film 16 is dry-etched via a resist pattern 17; an inter-connection is formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device forming highly reliable wiring and a method of manufacturing the same.

0002

2. Description of the Related Art In recent years, as semiconductor integrated circuits have become smaller, the influence of impurities contained in interlayer insulating films on wiring and silicon substrates cannot be ignored. Therefore, there is a strong need for a method of manufacturing a semiconductor device in which impurities contained in an interlayer insulating film do not affect the wiring or the silicon substrate when wiring is formed.

FIGS. 2A to 2F are cross-sectional views showing steps in a conventional method for manufacturing a semiconductor device. First, Figure 2 (a
), a silicon oxide film 2,
A silicon nitride film 3 and a silicon oxide film 4 containing boron and/or phosphorus are grown in this order, heat treated, and a contact hole is formed through a photoresist pattern 5 as shown in FIGS. 2(b) and 2(c). form. Next, after removing the photoresist pattern 5, as shown in FIG.
As shown in ~(f), an aluminum alloy film 6 is deposited,
Wiring is formed by dry etching this aluminum alloy film 6 through a photoresist pattern 7, and the silicon oxide film 4 containing boron and/or phosphorus forming an interlayer insulating film and the aluminum alloy forming the wiring. Membrane 6 was in direct contact.

0004

However, in the conventional semiconductor device manufacturing method as described above, impurities contained in the silicon oxide film 4 containing boron and/or phosphorus diffuse into the aluminum alloy film 6. However, there are problems in that it causes voids in the aluminum alloy film 6 and also diffuses into the silicon substrate 1 through the aluminum alloy film 6, causing variations in the characteristics of the transistor.

The present invention is an attempt to solve the above-mentioned conventional problems, and is capable of suppressing impurities contained in the silicon oxide film 4 containing boron and/or phosphorus from diffusing into the aluminum alloy film 6. The purpose is to provide an excellent semiconductor device and its manufacturing method.

[0006]

Means for Solving the Problems In order to achieve this object, a semiconductor device of the present invention includes a first silicon oxide film, a first silicon nitride film, a silicon oxide film containing at least one of boron and phosphorus, and a first silicon oxide film containing at least one of boron and phosphorus. A semiconductor device having a four-layer interlayer insulating film structure including a second silicon nitride film, a silicon oxide film containing at least one of boron and phosphorus, and a second silicon nitride film, a contact hole formed in the interlayer insulating film, and the contact. A side wall insulating film made of a third silicon nitride film and a second silicon oxide film formed on the side wall of the hole, and a wiring formed on the above-mentioned interlayer insulating film and connected to the surface of the semiconductor substrate through the above-mentioned contact hole. It consists of a semiconductor device, etc. having a configuration as follows.

[0007]

[Operation] With this configuration, the upper part of the silicon oxide film containing at least one of boron and phosphorus is covered with the second silicon nitride film, and the sidewall of the contact hole is made of the third silicon nitride film and the second silicon oxide film. Being covered with the sidewall insulating film makes it possible to suppress impurities contained in the silicon oxide film containing at least one of boron and phosphorus from diffusing into the aluminum alloy film or the silicon substrate.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1A to 1I show cross-sectional views of a method for manufacturing a semiconductor device according to an embodiment of the present invention. First, as shown in FIG. 1(a), a film with a thickness of 5 to 30 mm is coated on a silicon substrate 8 on which transistors and the like have already been formed.
first silicon oxide film with a thickness of 10 to 60 nm;
a silicon nitride film 10; a silicon oxide film 11 containing boron and/or phosphorus with a film thickness of 400 to 1,000 nm;
After growing in this order, heat treatment is performed at 800 to 950°C. Subsequently, as shown in FIG. 1(b), a second silicon nitride film 12 is grown to form an interlayer insulating film composed of the four layers described above, and a second silicon nitride film 12 is grown through a photoresist pattern 13 as shown in FIG. 1(c). Then, the interlayer insulating film composed of four layers is dry-etched using a fluorine-based gas to form a contact hole as shown in FIG. 1(d). Next, Figure 1(e)
As shown in the figure, a third silicon nitride film 14 with a thickness of 50 to 100 nm and a second silicon oxide film 15 with a thickness of 50 to 200 nm are grown in this order, and a third nitride film at the bottom of the contact hole is grown using a fluorine-based gas. Anisotropic dry etching is performed until the silicon film 14 and the second silicon oxide film 15 are etched and the silicon substrate 8 is exposed, and a third silicon nitride film 14 is formed on the side wall of the contact hole as shown in FIG. 1(f). A sidewall insulating film consisting of a second silicon oxide film 15 is formed to have a film thickness of 600 mm as shown in FIGS. 1(g) to 1(i).
Depositing an aluminum alloy film 16 of ~1,000 nm,
Wiring is formed by dry etching the aluminum alloy film 16 through the photoresist pattern 17 using chlorine and bromine gas.

As described above, according to this embodiment, the upper part of the silicon oxide film 11 containing boron and/or phosphorus is covered with the second silicon nitride film 12, and the side wall of the contact hole is covered with the third silicon nitride film 14. Since the silicon oxide film 1 containing boron and/or phosphorus is covered with the sidewall insulating film made of the second silicon oxide film 15
1 can be suppressed from diffusing into the aluminum alloy film 16 or the silicon substrate 8, thereby suppressing the effect on voids in the aluminum alloy film 16 and the transistors formed on the silicon substrate 8. can.

[0010] In the above embodiment, the wiring is made up of a single layer of an aluminum alloy film, but wiring made of a barrier metal alloy and an aluminum alloy may also be used.

[0011] Also, wiring other than an aluminum alloy film may be used.

0012

As described above, the present invention is composed of four layers: a first silicon oxide film, a first silicon nitride film, a silicon oxide film containing at least one of boron and phosphorus, and a second silicon nitride film. An interlayer insulating film, a contact hole formed in the interlayer insulating film, a sidewall insulating film made of a third silicon nitride film and a second silicon oxide film formed on the sidewall of the contact hole, and a semiconductor through the contact hole. Since the structure has a wiring such as an aluminum alloy film connected to the substrate surface, impurities contained in the silicon oxide film containing at least one of boron and phosphorus may be transferred to the aluminum alloy film or the silicon substrate. It is possible to provide an excellent semiconductor device and a method for manufacturing the same, which can suppress diffusion, thereby suppressing effects on voids in an aluminum alloy film, etc., and transistors formed on a silicon substrate.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the process order of a method for manufacturing a semiconductor device according to an embodiment of the present invention.

[Figure 2] Cross-sectional view of the process order of a conventional semiconductor device manufacturing method

[Explanation of symbols]

8 Silicon substrate (semiconductor substrate) 9 1st
Silicon oxide film 10 First silicon nitride film 11 Silicon oxide film 12 containing at least one of boron and phosphorus Second silicon nitride film 13 Photoresist pattern 14 Third silicon nitride film 15 Second silicon oxide film 16 Aluminum alloy film ( Wiring) 17 Photoresist pattern

Claims (4)

[Claims] 1. A first silicon oxide film, a first silicon nitride film, a silicon oxide film containing at least one of boron and phosphorus, and a second silicon nitride film, which are sequentially formed on a semiconductor substrate on which a transistor or the like is formed. A semiconductor device having an interlayer insulating film composed of four layers. 2. Consisting of four layers: a first silicon oxide film, a first silicon nitride film, a silicon oxide film containing at least one of boron and phosphorus, and a second silicon film, which are sequentially patterned on a semiconductor substrate. a contact hole formed by etching a portion of the interlayer insulating film; and a sidewall insulating film consisting of a third silicon nitride film and a second silicon oxide film sequentially formed on the sidewall of the contact hole. and a wiring formed on the interlayer insulating film and connected to the surface of the semiconductor substrate via the contact hole. 3. A first silicon oxide film, a first silicon nitride film, and a silicon oxide film containing at least one of boron and phosphorus are sequentially formed on a silicon substrate on which a transistor or the like is formed, and then heat treated. A method for manufacturing a semiconductor device, which includes at least the step of: forming an interlayer insulating film having a four-layer structure by growing a second silicon nitride film on the silicon oxide film containing at least one of boron and phosphorus; 4. The method for manufacturing a semiconductor device according to claim 3, wherein after forming an interlayer insulating film having a four-layer structure, a part of the interlayer insulating film is dry-etched using a photoresist pattern to form a contact hole. After removing the photoresist pattern, a step of sequentially forming a third silicon nitride film and a second silicon oxide film on the entire surface, and anisotropic drying of the third silicon nitride film and second silicon oxide film. etching to form a sidewall insulating film made of the third silicon nitride film and a second silicon oxide film on the sidewall of the contact hole; and connecting to the semiconductor substrate surface through the contact hole on the interlayer insulating film. A method for manufacturing a semiconductor device, comprising at least a step of patterning the wires formed in the pattern.