JPH0529482A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form electrode wiring which is free from blowholes and has a high aspect ratio by forming the first insulating film so that the insulating film can cover the side wall of an electrode wiring film and an overhang section below the side wall and second insulating film which covers the first insulating film after the outer edge of the first insulating film is etched with plasma ions. CONSTITUTION:An SiO2 film 18 is formed by isotropic coating so that the film 18 can have a uniform thickness and can fill up the overhang section 17 of an Al-wiring film 16 on an Si substrate 15 by irradiating the overhang section 17 with oxygen plasma under a non-bias condition. Then the corners of the film 18 are rounded by performing sputter etching of oxygen ions 19 by using an oxygen or argon gas. When a PSG film 20 is then formed in a uniform thickness, the overhang section 17 can be filled up and a two-layer covering insulating film can be formed of the SiO2 film 18 having the round corners and PSG film 20. Therefore, wiring having a high aspect ratio can be insulated from another wiring having another high aspect ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming method for a semiconductor device, and more particularly to a manufacturing method for forming an insulating film on an electrode wiring film having an inverse taper or an overhang portion in an ECR-P-CVD device. .

With increasing integration, the distance between the electrode wiring films has become narrower, and a higher aspect ratio between wirings has become a problem in the process. Since it is difficult to embed the insulating film between the wirings having the high aspect ratio, this hinders the large scale integration.

[0003]

2. Description of the Related Art FIG. 4 is an explanatory view of a conventional example. In the figure, 21 is a semiconductor substrate, 22 is an electrode wiring film, 23 is an overhang portion, 24 is an insulating film, 25 is an insulating film, and 26 is a void.

Conventionally, as shown in FIG. 4A, after forming an electrode wiring film 22 on a semiconductor substrate 21, a surface treatment is performed, and subsequently, as shown in FIG. After growing an insulating film 24 such as a silicon dioxide (SiO ₂ ) film on the electrode wiring film 22, the upper edge portion of the electrode wiring film 22 was sputtered with argon or the like to form a forward tapered shape. .

[0005]

When an insulating film is formed by an ECR-P-CVD apparatus, it has a feature that it is formed thick on the wiring and thin on the side wall because of strong anisotropy.

By utilizing this feature, it is possible to form a film in a forward taper shape on the wiring. However, if the wiring itself has a reverse taper, or if the overhanging portion 23 is formed below the side of the electrode wiring film 22 due to overetching, this strong anisotropy causes the formation of an overhang portion 23 as shown in FIG. In addition, the film is formed with a so-called "void" 26 in the cavity, which is not preferable in terms of characteristics.

In view of the above points, the present invention is ECR-P-
It is provided for the purpose of preventing generation of voids on the side wall of an electrode film when forming an insulating film on an electrode wiring film having an inverse taper or an overhang portion in a CVD device or the like.

[0008]

FIG. 1 illustrates the principle of the present invention. In the figure, 1 is a semiconductor substrate, 2 is an electrode wiring film, 3 is a first insulating film, 4 is an overhang portion, 5 is plasma ions, and 6 is a second insulating film.

With respect to the present invention which solves the above problems,
This will be described with reference to FIG. First, as shown in FIG.
On the semiconductor substrate 1 on which the electrode wiring film 2 is formed, the first insulating film 3 is formed so as to cover the side wall of the electrode wiring film 2 and the overhang portion 4 under the electrode wiring film 2.

Next, as shown in FIG. 1B, the first insulating film 3 is etched by plasma ions 5,
The outer edge of the first insulating film 3 is etched. Subsequently, as shown in FIG. 1C, a second insulating film 6 is formed so as to cover the first insulating film 3.

[0011]

According to the present invention, first, the first insulating film 3 is formed on the electrode wiring film 2 having an overhang portion or an inverse taper in a pressure range of several mm to Torr to several Torr without biasing. In this way, the pressure range is increased, the anisotropy is reduced, and the insulating film is evenly coated on the electrode wiring film.

After film formation, a bias is applied with oxygen plasma or argon plasma to carry out sputter etching to scrape the upper edge of the first insulating film to form a forward taper. Regarding plasma ions, oxygen plasma causes less damage to the semiconductor substrate than argon plasma.

Finally, a bias is applied to increase the anisotropy, and the second insulating film is coated in a forward taper shape. As a result, an electrode wiring film having a high aspect ratio can be formed.

[0014]

EXAMPLE FIG. 2 is a schematic sectional view of an ECR-P-CVD apparatus used in the present invention, and FIG. 3 is a schematic sectional view in order of steps of an example of the present invention.

In the figure, 7 is an electrostatic chuck, 8 is a reaction chamber, 9 is a plasma generation chamber, 10 is a solenoid coil, 11 is a sub-solenoid coil, 12 is a silane gas supply port, 13 is a nitrogen and oxygen gas supply port, 14 Is an exhaust port, 15 is a Si substrate, 16 is Al
A wiring film, 17 is an overhang portion, 18 is a SiO ₂ film, 19 is an O ion, and 20 is a PSG film.

An embodiment of the present invention will be described in the order of steps. As shown in FIG. 3A, an Al wiring film on the Si substrate 15 formed by lightly removing the natural oxide film on the surface with fluorine ions.
For the overhang portion 16 of 16, the device shown in FIG. 3 is used,
The Si substrate 15 is irradiated with oxygen plasma without bias, and the water adsorbed on the surface of the Si substrate 15 is scattered.

Then, as shown in FIG. 3B, 245 GHz
Microwave power of 400W, vacuum degree of 1-2mmTorr, isotropic coating using silane (SiH ₄ ) 20sccm, oxygen (O ₂ ) 20sccm, nitrogen (N ₂ ) 2sccm process gas, deposition time 30 In a second, the SiO ₂ film 18 is formed to have a uniform film thickness of 500 to 1,000 Å and the overhang portion 17 is filled.

Next, as shown in FIG. 3 (c), oxygen or argon (Ar) gas is used, and by O ions 19 or the like, microwave 2.45 GHz, output 400 W, RF frequency 13.56 MHz, 7
00W, vacuum degree 1～2MmTorr, perform sputter etching, abrading the upper edge of the SiO ₂ film 18, to slow the corners of the SiO ₂ film 18.

Then, the output of microwave of 245 GHz 400
W, RF frequency 13.56MHz, output 700W, degree of vacuum 1-2
mmTorr, SiH ₄ 20sccm, O ₂ 20sccm, N ₂ 2s in the reaction chamber
introducing a process gas _ccm, to form a 3,000 Å thick of phosphosilicate glass (PSG film) 20 a uniform thickness.

As a result, the overhang portion 16 is filled, and a two-layer cover insulating film of the SiO ₂ film 18 and the PSG film 20 having a gentle corner can be formed.

[0021]

As described above, according to the present invention,
Since a forward-tapered insulating film can be easily formed, it is possible to easily insulate between high-aspect-ratio wirings, which facilitates large-scale integration.

[Brief description of drawings]

FIG. 1 is an explanatory view of the principle of the present invention.

FIG. 2 is a schematic diagram of an ECR-P-CVD apparatus used in the present invention.

FIG. 3 is a schematic cross-sectional view in order of the processes of an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a conventional example.

[Explanation of symbols]

1 Semiconductor Substrate 2 Electrode Wiring Film 3 First Insulating Film 4 Overhang Part 5 Plasma Ion 6 Second Insulating Film 7 Electrostatic Chuck 8 Reaction Chamber 9 Plasma Generation Chamber 10 Solenoid Coil 11 Sub Solenoid Coil 12 Silane Gas Supply Port 13 Nitrogen , Oxygen gas supply port 14 Exhaust port 15 Si substrate, 16 Al wiring film, 17 Overhang part 18 SiO ₂ film 19 O ion 20 PSG film

Claims (1)

Claim: What is claimed is: 1. A method of manufacturing a semiconductor device using a plasma CVD method, comprising: forming a first substrate on a semiconductor substrate (1) having an electrode wiring film (2) formed thereon;
The first step of forming the insulating film (3), and the outer edge of the first insulating film (3) is tapered by etching the first insulating film (3) with plasma ions (5). And a third step of forming the second insulating film (6) so as to cover the first insulating film (3) and the first step is substantially the same. Without biasing the plasma, and with anisotropy such that the surface of the electrode wiring film (2) and the surface of the semiconductor substrate (1) are adhered and covered with the first insulating film (3). The method of manufacturing a semiconductor device is characterized in that the third step is performed by applying a bias to plasma and with a higher anisotropy than that of the first step.