JPH04133450A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a selective growth material from being grown on an antireflection film and to contrive to make a good selective growth of the material perform by a method wherein in the case where an opening is provided in a material film constituted by forming the antireflection film on an insulating film on a base body and the selective growth material is grown in the opening, an upper insulating film is further ready-provided on the antireflection film. CONSTITUTION:An insulating film 2 is formed on a base body 1, an antrireflection film 5 is formed on the film 2, an upper insulating film 6 is formed on the film 5, an opening 3 is formed in the above films 2, 5 and 6 to make at least the surface of the base body 1 expose and the opening 3 is filled by growing a selective growth material 4 in the opening 3. For example, an Si3N4 film is formed on an insulating film 2, which is formed on a semiconductor substrate to be used as a base body 1 and consists of a BPSG film, in a film thickness to meet an antireflection condition by a low-pressure CVD method. Then, an SiO2 film is further formed on the Si3N4 film in a thickness of 100Angstrom by a sputtering method or a CVD method. Then, a patterning is performed to form an opening 3 and after the surface of the base body 1 is made to expose, a selective W-CVD method is performed and W is selectively grown only in the opening 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device. The present invention
For example, it can be used to manufacture highly miniaturized and integrated semiconductor integrated circuits.

[Summary of the invention]

The present invention relates to a method for manufacturing a semiconductor device, in which an opening is formed in a material on which an anti-reflection film is formed on an insulating film on a substrate to grow a selectively grown material, and an upper insulating film is further provided on the anti-reflection film. This prevents the selective growth material from growing on the antireflection film, thereby allowing good selective growth to occur.

[Conventional technology]

In the field of semiconductor devices, miniaturization and integration are progressing more and more. For example, the minimum processing size of semiconductor integrated circuits is becoming finer year by year, and at the research and development level, for example, 0.50μ
It has reached a level of 0.35 μm, which is less than m. In particular, the dimensions of openings such as contact holes are approximately 0.4 μm. The contact hole must be filled with a conductive material to establish a connection, but it is not easy to fill a hole with such a minute opening size.

As a technique for burying such fine openings, a selective growth material deposition technique is attracting attention.

A typical example is W (tungsten) selection CVD.
It's technology. This is because when CVD is performed using tungsten fluoride (WF) gas, W does not grow on the oxide film.
It utilizes selective growth on the surface of polysilicon or silicon.

That is, as shown in FIG. 2A, an oxide film (SiO□, PSG, BPSG, etc.) is formed on a silicon or polysilicon substrate 1.
Regarding the structure in which an insulating film 2 made of impurity-containing silicon oxide (such as As5G) is formed, an opening 3 is formed as a contact hole in the insulating film 2 as shown in FIG. 2(B), and then CVD is performed using WF6 gas. When this is done, W does not grow on the insulating film 2, which is an oxide film, but only on the exposed part of the base 1, so W grows sequentially from the bottom of the opening 2 as shown in FIG. 2(C). A good buried portion 4 is selectively formed only in the opening 2.

On the other hand, as the minimum processing size has become smaller as described above, lithography techniques that use extremely short wavelength light such as KrF excimer laser are attracting attention. This is because processing using such short wavelength light allows the minimum processable dimension to be reduced and miniaturization to be achieved.

[Problem that the invention seeks to solve]

However, when processing is attempted using short wavelength light as described above, an antireflection film is required, and the use of an antireflection film poses a problem in that it becomes difficult to use the selective growth technique described above.

This will be discussed below.

Short-wavelength light, such as KrF excimer laser, has a wavelength in the deep UV region (250 nm), so the reflectance of the underlying substrate is high. Therefore, even if it is on an oxide film, the reflected light will return through the underlying layer, so anti-reflection is required. Moreover, when an antireflection film is formed on an oxide film, the surface material changes, making it difficult to perform selective growth using conventionally known methods.

That is, as shown in FIG. 3(A), an attempt was made to perform microfabrication using a KrF excimer laser on a material in which an insulating film 2 made of SiO□ or other oxide film is formed on a substrate 1 such as silicon. Then, reflection becomes a problem even on the silicon surface and even through the insulating film, making it impossible to form minute openings with high precision. Therefore, an anti-reflection film 5 is formed on the insulating film 2. The need arises. Next, this is photolithographically processed using the laser beam described above to form fine openings 3 as shown in FIG. 3(B). However, when attempting to fill this opening 3 by growing W or the like using a selective growth technique, some W grows not only on the opening 3 but also on the antireflection film 5, reducing the selectivity. Good embedding may not be possible, and W may peel off from the portion formed on the antireflection film 5. For example, peeling may occur during cleaning,
Alternatively, it may become dust, and there is also a possibility that W may fall off from the embedded portion 4.

In FIG. 3(C), reference numeral 41 indicates the growth of the selectively grown material on the antireflection film 5. In FIG.

As mentioned above, as extremely fine processing is required, there are cases where it is necessary to use an anti-reflection coating, and in such cases, selective growth technology cannot be applied as is. is difficult.

An object of the present invention is to solve this problem and provide a method for manufacturing a semiconductor device in which selective growth technology can be easily and favorably applied even when forming an antireflection film.

[Means for solving problems]

A method for manufacturing a semiconductor device according to the present invention includes forming an insulating film on a substrate, forming an anti-reflection film on the insulating film, forming an upper insulating film on the anti-reflection film, and forming an insulating film on the anti-reflective film. This method of manufacturing a semiconductor device is characterized in that an opening is formed in a prevention film and an upper insulating film to expose at least the surface of the substrate, and the opening is filled by growing a selectively grown material in the opening. This configuration solves the above-mentioned problems.

In the present invention, the insulating film refers to a material film that is not grown depending on the selectively grown material; for example, for W, it is an oxide film or the like.

An anti-reflection film has an anti-reflection function against the light of interest, and can be set depending on the material, film thickness, etc. Depending on the underlying material, it can be made of silicon nitride, TiN, Ti0N, a (amorphous)-3i, etc. It can be used as a material.

[For production]

According to the present invention, since the upper insulating film is further formed on the anti-reflection film, no selectively grown material is formed there, so that selective growth is performed only within the opening, and good embedding can be achieved.

〔Example〕

Embodiments of the invention will be described below with reference to the drawings.

However, it goes without saying that the present invention is not limited to the examples described below.

This embodiment embodies the present invention by using KrF excimer laser lithography technology to open a minute contact hole under antireflection conditions, and then forming an interlayer insulating film so that it can be filled with selective WCVD. It is.

Refer to FIGS. 1(a) to (e).

In this example, a 5-inch semiconductor substrate is used as the base 1, and BPSG (silicate glass containing boron phosphorus, refractive index 1.5 at 250 nm) is coated on this substrate with a film thickness of 5,000 nm.
The insulating film 2 was formed by forming a layer. As a result, the structure shown in FIG. 1(a) was obtained.

Next, silicon nitride (Si:+I'
J4) is formed by low-pressure CVD to a film thickness that satisfies anti-reflection conditions. For example, the refractive index at a thickness of 150 nm and 250 nm is set to 1.5. As a result, the antireflection film 5
The structure shown in FIG. 1(b) is obtained.

Next, SiO□ is further applied on top of this by sputtering method (or C
The structure of FIG. 1C having an upper layer insulating film 6 was obtained by forming a 100-layer film with a thickness of 7 using a VD method (VD method).

The anti-reflection function is provided by the anti-reflection film 5 consisting of the above 5i=N4.
Since both layers 5 and 6 serve this purpose, the desired antireflection conditions are achieved by combining both layers 5 and 6.

Next, by patterning, as shown in FIG. 1(d), openings 3 are formed in the insulating film 2, antireflection film 5, and upper insulating film 6 to expose at least the surface of the base 1. Specifically, in this example, as shown in FIG. 1(d), the surface of the base 1 was exposed at the entire bottom of the opening 3. That is, the bottom of the opening 3 was exposed to silicon where W could selectively grow.

In this example, buttering was performed as follows. That is, after the surface of the upper insulating film 6 on the upper surface was subjected to hydrophobic treatment, 0.7 μml of 5AL-601 was applied as a photoresist. This was performed using an excimer laser stepper (NA: 0.37
), with an exposure amount of 801 IIJ/c4, PEB (beta after exposure) was performed at 100°C for 60 seconds, and development was performed for 10 minutes with MF622, a developer for the above resist, to form a 0.4 μm contact hole. A resist pattern was formed. This is etched using a fluorine-based gas using a hexode type etching device, such as Ct F b 50S.
CCM (conditions of 300 mm), an opening 3 was formed to serve as a contact hole, and the resist was peeled off.

Next, when selective W-CVD was performed, W was selectively grown only in the opening 3, and as shown in FIG. A structure was obtained in which .

In this example, selective W-CVD was specifically performed as follows.

Gas system used: WFb/S i H4/H2-10/7
/1000 SCC? 1 Temperature: 260"C Pressure: 200 mTorr Of course, other gas systems may be used as appropriate, such as adding disilane or H2 to WF to perform reduction.

As described above, in this embodiment, by using the antireflection film 5, the fine openings 3 can be formed using the KrF excimer laser lithography technique, and even though the antireflection conditions are set in this way, , it was possible to selectively fill the opening 3 with the selectively grown material 4.

On the other hand, as a comparative example, under exactly the same conditions as in Example-1 described above, the upper insulating film 6 was not formed, but W was selected.
- CVD was performed. As a result, W grew over the entire surface including the antireflection film 6, and good selective growth was not possible.

In the above embodiment, the insulating film 2 was formed from BPSG, but
It may be a CVD film made of other impurity-containing glass such as PSG or As5G, or it may be a thermal oxidation film. An oxide film containing SiO□ can be satisfactorily carried out under the same conditions as in this example.

Although silicon nitride was used as the antireflection film, any material can be used as long as it provides the desired antireflection function.

Further, the upper insulating film 6 may also be formed by, for example, thermal oxidation or annealing.
In2 or the like may be formed.

Even when processing is performed using short wavelength light, the selective growth technique can be applied easily and favorably.

[Brief explanation of drawings]

[FIGS. 1(a) to 1(e)] The steps of Example-1 are sequentially shown in cross-sectional views. 2(A) to 2(C)] This shows the conventional technology, and particularly shows the substrate process of the selective CVD technology. [FIGS. 3(A) to 3(C)] FIGS. 3(A) to 3(C) are diagrams showing a conventional technique and particularly showing problems. [Explanation of symbols] 1... Base, 2... Insulating film, 3... Opening, 4...
- Selective growth material, 5... antireflection film, 6... upper layer insulating film. 〔Effect of the invention〕

Claims (1)

[Claims] 1. forming an insulating film on a substrate, forming an antireflection film on the insulating film, forming an upper insulating film on the antireflection film, the insulating film, the antireflection film, 1. A method of manufacturing a semiconductor device, comprising: forming an opening in an upper insulating film to expose at least the surface of the substrate; and filling the opening by growing a selectively grown material in the opening.