JPH09162291A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance a device in quality and reliability by a method wherein an interlayer insulating film of high quality is formed. SOLUTION: A silicon substrate 1 is covered with a lower insulating film 2, then a metal wiring 3 is formed on the lower insulating film 2, and a first insulating film 4 is formed through a plasma CVD. NH3 gas is photodissociated by irradiation with ArF excimer laser rays, and the silicon substrate 1 is optically excited, whereby a nitride oxide film 5 is formed as thick as 10nm or so at 400 deg.C or so. SOG solution is spin-applied onto the nitride oxide film 5, and a second insulating film 6 of SOG is formed through a heat treatment and then etched back to be flattened. A third insulating film 7 is formed on the nitride and oxide film 5 and the insulating film 6 through a plasma CVD to flatten the surface between the wirings. A nitride oxide film 8 is formed as thick as 10nm or so at a temperature of 400 deg.C or so the same as the nitride oxide film 5.

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, and more particularly, by nitriding the surface of an interlayer insulating film (oxide film) in a multi-layer wiring structure, the insulating property of the interlayer insulating film is improved, and thus a device is provided. The present invention relates to a semiconductor device manufacturing method capable of improving the quality and reliability of the semiconductor device.

[0002]

2. Description of the Related Art Conventionally, a silicon oxide film (hereinafter abbreviated as plasma oxide film) formed mainly by plasma CVD has been adopted as an interlayer insulating film in a multilayer wiring structure. This plasma oxide film is widely used because it can be formed at a low deposition rate at a low temperature. However, since the plasma oxide film is formed by the reaction in the non-thermal equilibrium state, the composition of the film is not necessarily the chemical composition like SiO ₂ . Therefore, there have been problems such as deterioration of the insulation property and the crack resistance of the insulation film.

As a countermeasure against this, it is conceivable to increase the thickness of the film. However, there is a limit to increase the thickness because it is necessary to reduce the aspect ratio in accordance with further miniaturization which will be further advanced in the future. Further, a nitride film may be used to improve the quality of the insulating film, but in the conventional thermal nitriding method for forming a nitride film, a high temperature treatment of 1000 ° C. or higher is performed.
The nitride film cannot be formed after forming the metal wiring. It is possible to deposit a nitride film by a CVD method (Japanese Patent Laid-Open No. 4-204,
In the technique of Japanese Patent No. 56254, a nitride film is formed on the interlayer insulating film by the CVD method. However, in this method, a defect peculiar to the interface between the high-density nitride film and the lower-density interlayer insulating film is generated, and the adverse effect due to the difference in stress between the nitride film and the interlayer insulating film is adversely affected. There was a problem that occurred.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to have excellent insulating properties and resistance to radiation, and a strong stopping power against impurity diffusion or oxidation. An object of the present invention is to provide a method for manufacturing a semiconductor device, which can improve the quality of the device by forming an interlayer insulating film which has less reaction with and which has excellent moisture resistance.

[0005]

A method of manufacturing a semiconductor device according to claim 1 is a method of manufacturing a semiconductor device having a multilayer wiring structure, in which an insulating film is formed after a semiconductor element is formed, and an insulating film is formed on the insulating film. A step of forming a plurality of metal wirings on the metal wirings and forming a first insulating film on the metal wirings by physical or chemical vapor deposition; and irradiating the surface of the first insulating film with an ArF excimer laser. A step of nitriding the surface of the first insulating film by supplying ammonia gas onto the film to photodissociate it, and a step of forming a second insulating film on the nitride film by coating and baking; And an etching back step for flattening the surface of the insulating film, and a step of forming a third insulating film on the etched back second insulating film by physical or chemical vapor deposition.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, the surface of the third insulating film is irradiated with ArF excimer laser, and ammonia gas is supplied onto the third insulating film. The method is characterized by including a step of nitriding the surface of the third insulating film by photodissociation.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. Example 1 FIGS. 1A to 1E are cross-sectional views sequentially showing manufacturing steps of a semiconductor device. First, according to a conventional technique, a silicon substrate 1 having semiconductor elements formed thereon is covered with a lower insulating film 2 as shown in FIG. 1A, and then metal wiring 3 is formed on the lower insulating film 2.
To form Next, as shown in FIG. 1B, a first insulating film 4 is formed on the entire surface of the silicon substrate 1 by plasma CVD so as to have a thickness of about 600 nm. After that, FIG. 1 (c)
ArF excimer laser irradiation is performed as shown in
By photoexciting the silicon substrate 1 at the same time as photodissociating the H ₃ gas, the oxynitride film 5 is heated to about 1 ° C at a temperature of about 400 ° C.
It is formed to a thickness of 0 nm. Next, as shown in FIG. 1D, an SOG solution is spin-coated on the oxynitride film 5, and then a heat treatment is performed to form a second insulating film 6 made of SOG, and then the insulating film 6 is etched. Flatten by back.
A third insulating film 7 is formed on the oxynitride film 5 and the insulating film 6 by plasma CVD to have a thickness of about 600 nm to flatten the space between the wirings.

Subsequently, as in the case of forming the oxynitride film 5, ArF excimer laser irradiation is performed as shown in FIG. 1 (e) to photodissociate the NH ₃ gas and at the same time photoexcite the silicon substrate 1, The oxynitride film 8 is formed at a temperature of about 400 ° C. to a thickness of about 10 nm. Since the nitrided oxide films 5 and 8 thus formed are denser than ordinary oxide films and have characteristics peculiar to nitride films,
This helps improve the quality of the interlayer insulating film.

[0009]

As is apparent from the above description, claim 1
In the method of manufacturing a semiconductor device described in (1), ArF excimer laser irradiation is performed to photodissociate NH ₃ gas and at the same time photoexcite the silicon substrate to form a oxynitride film on the insulating film, thereby relatively reducing the temperature to about 400 ° C. It becomes possible to form an interlayer insulating film that has excellent resistance to radiation and insulation at low temperatures, has a strong stopping power against impurity diffusion or oxidation, has little reaction with metals, and has excellent moisture resistance. . Therefore, according to the present invention, there is an effect that the quality and reliability of the device can be improved. The characteristics of the nitride oxide film are as excellent as those of the conventional nitride film formed by the high temperature treatment of 1000 ° C. or higher. Also,
In the method of manufacturing a semiconductor device according to claim 2, since the oxynitride film is formed on the first insulating film and the oxynitride film is formed on the third insulating film, the method is further improved as compared with the first aspect. High quality devices can be manufactured. In the manufacturing method according to the first and second aspects, a double-layered structure including the surface oxynitride film and the underlying oxide film is formed, but there is no clear boundary between them. For this reason, a nitride film C is formed on the interlayer insulating film.
The above problems associated with the conventional technique of forming by the VD method do not occur.

[Brief description of the drawings]

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

[Explanation of symbols]

 1 Silicon Substrate 2 Lower Layer Insulating Film 3 Metal Wiring 4 First Insulating Film 5 Nitride Oxide Film 6 Second Insulating Film 7 Third Insulating Film 8 Nitride Oxide Film

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H01L 21/90 Q

Claims (2)

[Claims] 1. A method of manufacturing a semiconductor device having a multilayer wiring structure, wherein an insulating film is formed after a semiconductor element is formed, a plurality of metal wirings are formed on the insulating film, and a physical or physical layer is formed on the metal wiring. The step of forming the first insulating film by chemical vapor deposition, and the step of irradiating the surface of the first insulating film with an ArF excimer laser and supplying ammonia gas onto the first insulating film to photodissociate them 1. A step of nitriding the surface of the first insulating film, a step of forming a second insulating film on the nitride film by coating and firing, an etchback step for flattening the surface of the second insulating film, and an etchback And a step of forming a third insulating film on the second insulating film by physical or chemical vapor deposition. 2. A step of nitriding the surface of the third insulating film by irradiating the surface of the third insulating film with an ArF excimer laser and supplying ammonia gas onto the third insulating film to photodissociate the same. 1. The method according to claim 1, wherein
A method of manufacturing a semiconductor device according to item 1.