KR20010063640A - Method for forming interlayer dielectric of semiconductor device - Google Patents

Abstract

PURPOSE: A method for manufacturing an interlayer dielectric of a semiconductor device is provided to improve a space burying characteristic and to stably bury tungsten of a via hole in forming a metal interconnection, by forming a spin-on-glass(SOG) layer as an interlayer dielectric for burying a space, and by etching back the SOG layer and forming an oxide layer in a high density plasma(HDP) apparatus. CONSTITUTION: A semiconductor substrate(21) having metal interconnections(22) is prepared. The first oxide layer(23) is deposited along the semiconductor substrate and the metal interconnections. A spin-on-glass(SOG) layer(24) is deposited on the first oxide layer to completely bury the space between the metal interconnections. The SOG layer is etched back to expose the first oxide layer. The second oxide layer(25) is formed on the etched-back SOG layer.

Description

METHODS FOR FORMING INTERLAYER DIELECTRIC OF SEMICONDUCTOR DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an interlayer insulating film of a semiconductor device, and more particularly, to a method for forming an interlayer insulating film of a semiconductor device capable of obtaining stabilization of a metal wiring process while ensuring space filling characteristics.

BACKGROUND ART With high integration of semiconductor devices, high density plasma deposition (HDP) oxide films are used as interlayer insulating films. This is because the oxide film deposited by the HDP equipment has excellent space filling characteristics.

However, in the trend that the spacing between the patterns (hereinafter, spacing) is further reduced along with the width of the pattern, for example, when the spacing is 0.35 μm or less, even if the HDP equipment is used, even with the HDP oxide film, Landfilling is not obtained, and hence reliability of the device cannot be secured.

That is, as shown in FIG. 1, when the HDP oxide film 3 is deposited as an interlayer insulating film on the semiconductor substrate 1 on which the metal wires 2 are formed by spacing of 0.35 μm or less, the HDP buried in the spacing portion is deposited. Voids (4) are generated in the oxide film portion, and the voids 4 lower the reliability of the device.

Therefore, it is expected that the use of the above-described HDP oxide film will be difficult in the semiconductor manufacturing process having a critical dimension of 0.15 mu m or less.

On the other hand, in forming the interlayer insulating film, the deposition thickness should be determined in consideration of the planarization process using a chemical mechanical polishing (CMP) process to be performed subsequently. For example, in the case of depositing an HDP oxide film as an interlayer insulating film, conventionally, the HDP oxide film is deposited to a thickness sufficient to fill a space in consideration of the productivity (through-put) of the deposition equipment, and the remaining thickness is higher than that of the HDP oxide film. An oxide film (hereinafter referred to as a PECVD oxide film) by a good productivity PECVD method is deposited.

However, as shown in FIG. 2, the PECVD oxide film 14 has a void 15 generated therein due to the characteristics of the deposition equipment, and in particular, the void 15 is exposed in a subsequent CMP process. Therefore, impurities such as slurry exist in the voids 15, resulting in deterioration of device characteristics. Here, reference numeral 11 denotes a semiconductor substrate, 12 a metal wiring, and 13 an HDP oxide film.

Therefore, in recent years, by using an organic or inorganic spin on glass (SOG) film having improved space filling characteristics as a material of an interlayer insulating film, it is possible to prevent deterioration of device characteristics due to voids.

However, when using an organic or SOG film as described above, there are the following problems.

First, in the case of using the organic SOG film, since the via hole is formed in the organic SOG film in a subsequent metallization step, if the via hole is filled with tungsten, out-gassing from the organic SOG film ( There is a problem that the tungsten buried of the via hole is not made by out-gassing.

Next, in the case of using an inorganic SOG film, the problem caused by the out-gassing does not occur, but a crack is generated inside the film due to the stress caused by the shrinkage of the SOG film during the subsequent thermal process. By doing so, there is a problem that element characteristics are deteriorated due to such cracks.

Accordingly, the present invention has been made to solve the above problems, to provide a method for forming an interlayer insulating film of a semiconductor device to ensure that the subsequent metal wiring process can be performed stably while ensuring the space filling characteristics. have.

1 and 2 are views for explaining a conventional problem.

3A and 3B are cross-sectional views illustrating a method for forming an interlayer insulating film of a semiconductor device according to an embodiment of the present invention.

4 is a cross-sectional view for describing a method for forming an interlayer insulating film of a semiconductor device according to another embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

21 semiconductor substrate 22 metal wiring

23: first oxide film 24: SOG film

25: second oxide film

The interlayer insulating film forming method of the present invention for achieving the above object comprises the steps of: providing a semiconductor substrate formed with metal wiring; Depositing a first oxide film along surfaces of the semiconductor substrate and the metal interconnection; Depositing an SOG film on the first oxide film so that the space between the metal wires is completely filled; Etching back the SOG film to expose the first oxide film; And forming a second oxide film on the etched back SOG film.

According to the present invention, since space filling is performed by using an SOG film, generation of voids can be prevented, and by removing the SOG film at a portion where a via hole is to be formed through an etch back on the organic SOG film, In the subsequent metallization process, the filling of the via holes may be stably performed.

(Example)

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3A and 3B illustrate a method of forming an interlayer insulating film of a semiconductor device according to an embodiment of the present invention.

First, as shown in FIG. 3A, metal wires 22 are formed on the semiconductor substrate 21 at predetermined intervals, and then the surfaces of the semiconductor substrate 21 and the metal wires 22 are formed. Thus, the first oxide film 23 is deposited, and then, the SOG film 24 is thick enough to completely fill the space between the metal wires 22 on the first oxide film 23. Deposit.

Here, the first oxide film 23 is a sacrificial oxide film for the etch back of the SOG film 24 to be subsequently performed, and is formed of a PECVD oxide film, which will be described later, as an HDP oxide film as the first oxide film 23. It is also possible to form In addition, both the SOG film 24 and the organic or inorganic SOG film may be used.

Then, as illustrated in FIG. 3B, an etch back process is performed on the SOG film 24 in the HDP equipment until the first oxide film 23 is exposed, and then, in the HDP equipment, the etch back process is performed. The second oxide film is deposited on top of the resultant product.

As a result of the etch back of the SOG film 24, the SOG film 24 remains only in the space between the metal wires 22. Therefore, even when the organic SOG film is used, since the SOG film does not exist in the portion where the via hole is to be formed in the subsequent metallization process, that is, the upper portion of the metallization 22, no buried tungsten due to out-gassing does not occur. In addition, since the SOG film 24 remains only in the space between the metal wires 22, as described above, even if an inorganic SOG film is used, no cracking occurs due to the subsequent thermal process. Therefore, the SOG film may be made of both organic and inorganic materials.

On the other hand, as an interlayer insulating film for space filling, although an SOG film is used in the embodiment of the present invention, a low dielectric constant dielectric film such as a-C: F (amorphous fluoronated cabon) may be formed by spin coating.

4 is a view for explaining a method for forming an interlayer insulating film of a semiconductor device according to another embodiment of the present invention. In this embodiment, an HDP oxide film is used as the material of the first oxide film 23 in comparison with the previous embodiment. The use is different and is performed in the same process. In particular, the etch back of the SOG film 24 and the formation of the second oxide film 25 are performed in HDP equipment.

As described above, the present invention forms an SOG film as an interlayer insulating film for space filling, and subsequently forms an etch back and an oxide film of the SOG film in the HDP equipment, thereby improving space filling characteristics. In the subsequent metallization process, stabilization of the tungsten buried of the via hole can be obtained.

In addition, since the etch back of the SOG film and the deposition of the oxide film are performed in the HDP equipment, an increase in equipment investment cost can be prevented.

In addition, not only an SOG film having excellent space filling characteristics is used, but also stability of a subsequent metallization process can be ensured, so that it can be very advantageously applied to the production of highly integrated devices of 0.15 µm or less in the future.

Meanwhile, although specific embodiments of the present invention have been described and illustrated, modifications and variations can be made by those skilled in the art. Accordingly, the following claims are to be understood as including all modifications and variations as long as they fall within the true spirit and scope of the present invention.

Claims (4)

Providing a semiconductor substrate having metal wirings formed thereon; Depositing a first oxide film along surfaces of the semiconductor substrate and the metal interconnection; Depositing an SOG film on the first oxide film so that the space between the metal wires is completely filled; Etching back the SOG film to expose the first oxide film; And Forming a second oxide film on the etched back SOG film. The method of claim 1, wherein the first oxide film is one selected from a PECVD oxide film and an HDP oxide film. The method for forming an interlayer insulating film of a semiconductor device according to claim 1, wherein the SOG film is an organic or inorganic SOG film. The method of claim 1, wherein the etch back of the SOG film and the deposition of the second oxide film are continuously performed in the same high density plasma deposition apparatus.