JPH06310505A - Method of manufacturing semiconductor device - Google Patents

Abstract

PURPOSE:To prevent swelling of a SOG film by a method wherein insulation films composed of the SOG film being a second insulation film and a third insulation film are etched back on a first insulation film and a fourth insulation film is accumulated and formed on the entire surface. CONSTITUTION:An aluminum film is formed on an insulation film 2 formed on a silicon wafer 1 and patterned to form an aluminum wire 4. Thereafter a SiO2 film 3 is formed on the entire surface. An anneal processing is performed within a plasma CVD device under the nitrogen atmosphere to form a SOG film 5. Further, a SiO2 film 6 is formed on the SOG film 5. Thereafter, the SiO2 and SOG film 5 are etched back to form again a SiO2 film 7 on the entire surface by a plasma CVD method. Thereafter, a via contact 9 is formed in the insulation film on the aluminum wire 4 and further an aluminum wire 8 being an upper layer wire is pattern-formed. Thus, the SOG film 5 does not directly come into contact with the outer atmosphere and swelling of the SOG film 5 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an SOG for an interlayer insulating film.
The present invention relates to a method for manufacturing a semiconductor device using a (Spin On Glass) film.

[0002]

2. Description of the Related Art In recent years, with the high integration of semiconductor devices, multilayer wiring has been advanced. In this multilayer wiring technique, the surface of the underlying film of the wiring film is required to be as flat as possible from the viewpoint of the reliability of the wiring film, and the SOG film is used as one of the flattening techniques therefor. The SOG film is a silicon oxide film obtained by applying an SOG solution in which a silicon compound is dissolved in an organic solvent to a wafer and subjecting the wafer to heat treatment. Phosphorus and boron are usually added to the SOG solution to control the viscosity.

A multilayer wiring technique using this SOG film will be described with reference to FIG.

First, as shown in FIG. 5A, an aluminum film is formed on the insulating film 2 formed on the silicon wafer 1 by a method such as sputtering, and this is patterned to form lower wiring. The aluminum wiring 4 is formed. After that, the SiO ₂ film 3 is formed on the entire surface by the plasma CVD method.

Next, as shown in FIG. 5B, an SOG solution is coated on the entire surface by, for example, a spin coating method, and the SOG solution is heat treated to be made inorganic, thereby forming an SOG film 5.

Next, as shown in FIG. 5D, the SOG film 5 on the aluminum wiring 4 is completely removed and the SOG film 5 is etched back in order to improve the flatness, and then the plasma CVD method is performed. Again the SiO ₂ film 7
To form a film.

Thereafter, as shown in FIG. 5E, a via contact 9 is formed in the insulating film on the aluminum wiring 4, and the upper aluminum wiring 8 is patterned.

Incidentally, in the step shown in FIG. 5D, the SOG film 5 on the aluminum wiring 4 is all removed by the process shown in FIG.
SO is formed on the side surface of the via contact 9 formed in the step (e).
This is to prevent the G film 5 from being exposed.

[0009]

However, in the above-described conventional manufacturing method, if the wafer is left in the atmosphere for a long time until the etching back is performed after the SOG film 5 is formed, oxygen in the atmosphere is Reacts with phosphorus in the SOG film 5, and as shown in FIG.
There is a problem that swelling containing P ₂ O ₅ as a main component occurs in a portion having a high phosphorus concentration.

This swelling does not disappear even if the SOG film 5 is etched back. When the upper aluminum wiring 8 is formed with such a swelling remaining, the bulging portion has a high phosphorus concentration, and thus the air is exposed to the atmosphere. H due to the reaction between water and phosphorus
₃ PO ₄ is generated, and as shown in FIG. 5 (e), the upper aluminum wiring 8 is corroded by this H ₃ PO ₄ (A in the figure), and the reliability of the semiconductor device is deteriorated. was there.

Therefore, conventionally, the above problem has been avoided by shortening the time for which the wafer on which the SOG film 5 is formed is left in the air as much as possible. Specifically, S
The OG solution coating process, the heat treatment process, the etch back process, and the insulating film formation process by plasma CVD are treated as a series of processes, and the processes are performed with a time limit provided between the processes.

However, when the processing is performed with the time limit set as described above, there is a drawback that it is very difficult to deal with a sudden trouble during the process.

Therefore, an object of the present invention is to deposit an insulating film on the SOG film immediately after the formation of the SOG film so that the SOG film is formed on the wafer even if the wafer is left in the atmosphere for a long time. It is an object of the present invention to provide a method for manufacturing a semiconductor device in which no bulge occurs.

[0014]

In order to solve the above-mentioned problems, a method of manufacturing a semiconductor device according to the present invention comprises a step of depositing and forming a first insulating film on a base on which an interlayer insulating film is to be formed. A step of applying an SOG solution on the first insulating film and heat-treating the solution to form an SOG film which is a second insulating film; and a step of depositing and forming a third insulating film on the SOG film. And a step of etching back the insulating film composed of the first insulating film, the SOG film and the third insulating film,
And a step of depositing and forming a fourth insulating film on the entire surface.

In this case, preferably, the first insulating film, the third insulating film and the fourth insulating film are silicon oxide films or silicon nitride films formed by a plasma CVD method.

Further preferably, the heat treatment for forming the SOG film is performed in a plasma CVD apparatus.

According to another aspect of the present invention, a method of manufacturing a semiconductor device includes a step of depositing and forming a first insulating film on a base on which an interlayer insulating film is to be formed, and a step of depositing the first insulating film on the first insulating film. SO
A step of applying a G solution and heat-treating the solution to form a first SOG film which is a second insulating film; and a step of depositing and forming a third insulating film on the first SOG film. A step of applying an SOG solution on the third insulating film and heat-treating the solution to form a second SOG film which is a fourth insulating film; and a step of forming a second SOG film on the second SOG film. A step of depositing and forming an insulating film, and etching back the insulating film including the first insulating film, the first SOG film, the third insulating film, the second SOG film, and the fifth insulating film. Step 6 and the entire surface
And a step of depositing and forming an insulating film.

In this case, preferably, the first insulating film, the third insulating film, the fifth insulating film, and the sixth insulating film.
The insulating film is a silicon oxide film or a silicon nitride film formed by the plasma CVD method.

In still another aspect of the present invention, a method of manufacturing a semiconductor device includes a step of depositing and forming a first insulating film on a base on which an interlayer insulating film is to be formed, and a step of depositing the first insulating film on the first insulating film. A step of applying a SOG solution to the substrate and heat-treating the solution to form a first SOG film which is a second insulating film;
The SOG solution is applied on the G film and heat-treated to make the third
Forming a second SOG film, which is an insulating film, a step of depositing and forming a fourth insulating film on the second SOG film, the first insulating film, the first SOG film , Above second
Of the SOG film and the fourth insulating film, and a step of depositing and forming a fifth insulating film on the entire surface.

In this case, preferably, the first insulating film, the fourth insulating film and the fifth insulating film are silicon oxide films or silicon nitride films formed by a plasma CVD method.

Further preferably, the second SOG
Heat treatment for forming a film is performed in a plasma CVD apparatus.

[0022]

In the present invention, since the insulating film is deposited and formed on this SOG film immediately after the uppermost SOG film is formed, this S
Even if a wafer having an OG film formed thereon is left in the air for a long time, the SOG film is protected by an insulating film having excellent moisture resistance deposited and formed on the SOG film, which causes swelling as in the conventional case. There is no.

[0023]

Embodiments of the present invention will be described below with reference to FIGS. In these embodiments, the same reference numerals are given to the portions corresponding to the conventional example described in FIG.

FIG. 1 shows a method of manufacturing a semiconductor device according to the first embodiment of the present invention.

First, as shown in FIG. 1A, an aluminum film is formed on the insulating film 2 formed on the silicon wafer 1 by a method such as sputtering, and this is patterned to form a lower layer wiring. The aluminum wiring 4 is formed. After that, the SiO ₂ film 3 is formed on the entire surface by the plasma CVD method.

Next, as shown in FIG. 1B, the SOG solution is applied to the entire surface by, for example, a spin coating method. And
The wafer is placed in a plasma CVD apparatus and annealed at 400 ° C. for 30 minutes in a nitrogen atmosphere under normal pressure. This allows
The inorganicized SOG film 5 is formed.

Next, as shown in FIG. 1C, the pressure inside the plasma CVD apparatus is reduced to 9 Torr, the wafer temperature is 400.degree.
The O ₂ film 6 is formed. In this state, the wafer was left in the atmosphere for one week, but the SOG film 5 did not swell.

Next, as shown in FIG. 1D, the SOG film 5 on the aluminum wiring 4 is completely removed, and the SOG film 5 is etched back to improve the flatness, and then the plasma CVD method is performed. Again the SiO ₂ film 7
To form a film.

Thereafter, as shown in FIG. 1E, a via contact 9 is formed in the insulating film on the aluminum wiring 4, and the aluminum wiring 8 as the upper layer wiring is further patterned.

In the manufacturing method of this embodiment, as shown in FIG.
The steps up to forming the upper layer aluminum wiring 8 were carried out for 25 wafers left in the atmosphere at the stage shown in (1), and after the sintering treatment, the aluminum wiring 8 was inspected for corrosion. As a result, the aluminum wiring 8 was not corroded on any of the wafers, and the SOG film 5 was not swollen at all.

FIG. 2 shows a method of manufacturing a semiconductor device according to the second embodiment of the present invention. In this example, two layers of SOG film are applied to improve the flatness of the wafer surface.

First, as shown in FIG. 2A, an aluminum film is formed on the insulating film 2 formed on the silicon wafer 1 by a method such as sputtering, and this is patterned to form lower layer wiring. The aluminum wiring 4 is formed. After that, the SiO ₂ film 3 is formed on the entire surface by the plasma CVD method.

Next, as shown in FIG. 2B, the SOG solution is applied to the entire surface by, eg, spin coating. And
The wafer is placed in a plasma CVD apparatus and annealed to form an inorganic first layer SOG film 10. After this, plasma CVD processing is subsequently performed, and S
The SiO ₂ film 6 is formed on the OG film 10.

Next, as shown in FIG. 2C, the SOG solution is applied again to the entire surface by, for example, a spin coating method, and annealed in the plasma CVD apparatus to make the inorganic second layer SOG. The film 11 is formed. Then, after this, a plasma CVD process is subsequently performed to form a SiO ₂ film 6 ′ on the SOG film 11.

Next, as shown in FIG. 2D, an etchback process is performed to remove all of the SOG films 10 and 11 on the aluminum wiring 4 and to improve the flatness, and then the plasma CVD method. To re-cover the entire surface with SiO
_{2 The} film 7 is formed.

Thereafter, as shown in FIG. 2E, a via contact 9 is formed in the insulating film on the aluminum wiring 4, and the aluminum wiring 8 as the upper layer wiring is further patterned.

In the case of the SOG film two-layer coating as in this embodiment, conventionally, after forming the first layer SOG film 10, Si is formed.
The _second SOG film 11 is formed without forming the O ₂ film 6,
Further, the SiO ₂ film 6 ′ is formed on the second SOG film 11.
Did not form. Therefore, the SOG of the first layer is conventionally used.
The process from the solution coating process to the film formation process of the SiO ₂ film 7 after etch back had to be treated as a series of processes with a time limit between the processes.

On the other hand, in the method of this embodiment, the SiO ₂ film 6 is formed by the plasma CVD method immediately after the first SOG film 10 is formed, and the second SOG film 11 is formed.
Immediately after the formation of SiO _{2, the} SiO ₂ film 6'is formed by the plasma CVD method. Therefore, the SiO ₂ film 6 or 6 '
After forming the wafer, the wafer can be left in the atmosphere, and it is not necessary to treat the wafer as a series of steps as in the conventional case. For example, in the method of the present embodiment, the wafer was left in the atmosphere for one week in the state shown in FIGS. 2B and 2C, but in any case, S
No swelling of the OG film occurred.

FIG. 3 shows a method of manufacturing a semiconductor device according to the third embodiment of the present invention.

In this embodiment, first, as shown in FIG. 3A, an aluminum film is formed on the insulating film 2 formed on the silicon wafer 1 by a method such as sputtering, and the aluminum film is formed. The patterning is performed to form the aluminum wiring 4 serving as the lower layer wiring. After that, the SiO ₂ film 3 is formed on the entire surface by the plasma CVD method.

Next, as shown in FIG. 3B, an SOG solution is applied to the entire surface by, for example, a spin coating method, and this is annealed to form a first-layer SOG film 10.

Next, as shown in FIG. 3 (c), the SOG solution is coated again on the entire surface by, for example, a spin coating method, and the SOG solution is put into a plasma CVD apparatus.
By performing annealing for 30 minutes, the second-layer SOG film 11 is formed. Then, after that, the plasma CVD process is subsequently performed to form the SiO ₂ film 6 on the SOG film 11.

Next, as shown in FIG. 3D, an etchback process is performed to remove all the SOG films 10 and 11 on the aluminum wiring 4 and to improve the flatness, and then the plasma CVD method. To re-cover the entire surface with SiO
_{2 The} film 7 is formed.

After that, as shown in FIG. 3E, a via contact 9 is formed in the insulating film on the aluminum wiring 4, and the aluminum wiring 8 which is an upper wiring is patterned.

The manufacturing method of this embodiment is based on the finding that the swelling of the SOG film generated by leaving it in the air disappears by the re-annealing. For example, in the method of this embodiment, after the SOG annealing was performed in the state of FIG. 3B, the wafer was left in the atmosphere, but the SOG film 10 bulged after about 4 hours. So, this SOG
Under the above-mentioned conditions, the second layer of SO
When the G film 11 was formed, the swelling that had occurred in the first SOG film 10 disappeared.

Further, in the manufacturing method of this embodiment, as shown in FIG.
The wafer was left in the air in the state of (c) for one week, but SOG
No blistering of the film occurred. Further, with respect to the wafer left in the air for one week, the steps up to the formation of the upper aluminum wiring 8 were performed, the sintering treatment was performed, and the corrosion of the aluminum wiring 8 was inspected. No corrosion and no swelling of the SOG film were observed.

In the above embodiment, the SOG films 5 and 1 are used.
Although the SiO ₂ films 6, 6 ′ and 7 are formed on 0 and 11 by the plasma CVD method, the same effect can be obtained by forming the SiN film by the plasma CVD method instead of these. can get.

FIG. 4 shows an example of a plasma CVD apparatus for performing SOG annealing and plasma CVD for forming a SiO ₂ film in each of the above-described embodiments.

The apparatus comprises a chamber 21, a susceptor 23 for supporting the wafer 22, a lamp heater 24 for heating the wafer 22 via the susceptor 23, and a quartz lamp window for transmitting radiation from the lamp heater 24. 25, a gas line 26 for introducing a process gas into the chamber 21, an exhaust port 27 for discharging the process gas from the chamber 21, an RF electrode 28, and the RF electrode 2
It has a gas inlet 29 for introducing gas into the vicinity of 8, and a dry pump 30 for reducing the pressure in the chamber 21.

When the SOG is annealed by this apparatus, as shown in FIG. 4 (a), N ₂ gas which is an atmospheric gas is introduced from the gas line 29 and the inside of the chamber 21 is kept at a normal pressure and the lamp heater is heated. The wafer 22 is heated by 24.

When plasma CVD is performed by this apparatus, as shown in FIG. 4 (b), the dry pump 3 is used.
The inside of the chamber 21 is decompressed by 0, and SiH ₄ , N ₂ O, TEOS, and O ₂ which are process gases from the gas line 26
Gas is introduced and the wafer 22 is heated by the lamp heater 24 while the RF electrode 28 is operated to generate plasma CV.
Do D.

[0052]

According to the method of manufacturing a semiconductor device of the present invention, an insulating film is deposited and formed on the SOG film immediately after the SOG solution is heat-treated to form the SOG film. However, the SOG film does not come into direct contact with the atmosphere, and it is possible to prevent the SOG film from bulging. Therefore, it is possible to prevent corrosion of the upper metal wiring due to the swelling of the SOG film, and it is possible to manufacture a highly reliable semiconductor device.

Further, according to the method of manufacturing a semiconductor device of the present invention, it is not necessary to treat all steps from the SOG solution coating step to the insulating film deposition step after the etch back as a conventional process, unlike the conventional method. Since it is only necessary to handle the steps from the insulating film deposition step to the subsequent steps as a series of steps, the degree of freedom in time between steps is increased, and lot handling becomes easier.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a method of manufacturing a semiconductor device according to a first embodiment of the present invention in the order of steps.

FIG. 2 is a schematic cross-sectional view showing a method of manufacturing a semiconductor device according to the second embodiment of the present invention in the order of steps.

FIG. 3 is a schematic sectional view showing a method of manufacturing a semiconductor device according to a third embodiment of the present invention in the order of steps.

FIG. 4 is a plasma C used to carry out the present invention.
It is a schematic diagram showing an example of a VD device.

FIG. 5 is a schematic cross-sectional view showing a conventional method of manufacturing a semiconductor device in the order of steps.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Silicon wafer 2 Insulating film 3, 6, 6 ', 7 SiO ₂ film 4, 8 Aluminum wiring 5 SOG film 9 Via contact 10 First layer SOG film 11 Second layer SOG film

Claims (8)

[Claims] 1. A first substrate on which an interlayer insulating film is to be formed.
The step of depositing and forming an insulating film, the step of applying an SOG solution on the first insulating film and heat-treating the SOG solution to form an SOG film which is a second insulating film, and the step of forming an SOG film on the SOG film. A step of depositing and forming a third insulating film, a step of etching back the insulating film composed of the first insulating film, the SOG film and the third insulating film, and a fourth insulating film being deposited on the entire surface. And a step of forming the semiconductor device. 2. The first insulating film, the third insulating film, and the fourth insulating film are silicon oxide films or silicon nitride films formed by a plasma CVD method. 1. The method for manufacturing a semiconductor device according to 1. 3. The heat treatment for forming the SOG film is performed in a plasma CVD apparatus.
A method of manufacturing a semiconductor device according to item 1. 4. A first substrate on which an interlayer insulating film is to be formed.
The step of depositing and forming an insulating film, the step of applying an SOG solution on the first insulating film, and heat-treating the solution to form a first SOG film which is a second insulating film; A step of depositing and forming a third insulating film on the first SOG film, and a step of applying an SOG solution on the third insulating film and heat-treating the SOG solution to form a second SOG which is a fourth insulating film. A step of forming a film, a step of depositing and forming a fifth insulating film on the second SOG film, a step of forming the first insulating film, the first SOG film, the third insulating film, A method of manufacturing a semiconductor device, comprising: a step of etching back an insulating film composed of a second SOG film and the fifth insulating film; and a step of depositing and forming a sixth insulating film on the entire surface. 5. The first insulating film, the third insulating film,
The fifth insulating film and the sixth insulating film are plasma C
The method of manufacturing a semiconductor device according to claim 4, wherein the method is a silicon oxide film or a silicon nitride film formed by a VD method. 6. A first substrate on which an interlayer insulating film is to be formed.
The step of depositing and forming an insulating film, the step of applying an SOG solution on the first insulating film, and heat-treating the solution to form a first SOG film which is a second insulating film; A step of applying an SOG solution on the first SOG film and heat-treating the SOG solution to form a second SOG film which is a third insulating film; and a fourth insulating film on the second SOG film. Depositing and forming the first insulating film, the first SOG film, and the second S film.
A method of manufacturing a semiconductor device, comprising: a step of etching back an insulating film composed of an OG film and the fourth insulating film; and a step of depositing and forming a fifth insulating film on the entire surface. 7. The first insulating film, the fourth insulating film, and the fifth insulating film are silicon oxide films or silicon nitride films formed by a plasma CVD method. 7. The method for manufacturing a semiconductor device according to 6. 8. The method of manufacturing a semiconductor device according to claim 5, wherein the heat treatment for forming the second SOG film is performed in a plasma CVD apparatus.