JPH03177044A - Formation of inter-element separating region - Google Patents

Abstract

PURPOSE:To easily form an inter-element separating structure by forming an overhanging type opening in a resist on a substrate to form a groove in the substrate, and then providing an insulating material in this groove and on the resist, and then removing the resist so that the resist is left only in the groove. CONSTITUTION:A resist 2 is applied on a substrate 1, on which an inter-element separating region is to be formed, and this resist 2 is exposed and developed to form an overhanging type opening 3, and a groove 4 is formed in the substrate 1 by using the resist 2 as a mask, and then an insulating component 51 is buried in this groove 4 and a film 52 consisting of an insulating component on the resist 4. Next, the film 52 consisting of the insulating component on the resist 2 is removed by removing the resist 2 to leave the insulating component 51 in the groove 4 to form an inter-element separating structure. Then, baking is carried out to obtain the final structure. Thus, a sure trench inter- element separating region can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming an isolation region between elements. The present invention
For example, it can be used to form isolation regions between elements in various semiconductor devices. In particular, the present invention can be suitably implemented in the case where a chemically amplified resist is used to form # regions corresponding to the number of elements.

[Summary of the invention]

In the method of forming the M region for the amount of elements of the present invention, an overhang-shaped opening is formed in a resist on a substrate, thereby forming a groove in the substrate, and then an insulating material is provided between the groove and the resist, and the resist is removed. By leaving the insulating material only in the grooves, it is possible to easily form an isolation structure between elements.

[Prior Art and its Problems] As a conventional technique of this kind, for example, a LOCOS method has been used as a method for separating elements in semiconductor integrated circuits. However, as the minimum dimensions of semiconductor integrated circuits have become smaller, problems such as the occurrence of bird's beak and conversion differences have become more serious in the simple LOCOS method. For this reason, the F-LOCO5 method (flame dolorous method), etc., which is an improvement on the conventional LOCO5 method, has been developed, but it is said that such technology will eventually reach its limit.

Under these circumstances, element isolation technology using a trench method is attracting attention, and it is thought that a method for forming an element isolation region using trenches will be essential for, for example, 0.35 μm class devices.

A conventional method of forming an isolation region between elements by widening a trench is shown in the order of steps in FIG.

A substrate l on which an element isolation region shown in FIG. 3(a) is to be formed.
Apply resist 2 on top as shown in Figure 3(b),
This resist 2 is exposed and developed by photolithography to form an opening 31 as shown in FIG. 3(c). Use this as a mask to form the groove 4 in the substrate 1.
3(d)), the resist 2 is removed to form a substrate 1 having grooves 4 as shown in FIG. 3(e). By depositing an insulating material such as 5 iOz on this, an insulating film 6 is formed in the groove 4 and on the substrate 1 (FIG. 3(f)). Next, the entire surface is etched back, leaving the insulating material 61 only in the groove 4, and the third
The structure shown in Figure (g) is an isolation region between elements.

Among the above steps, the etch hack step is particularly difficult. Although Fig. 3 simply depicts the etch-back process as being completed on the surface of the substrate 1, in reality, an etch-back stopper is shown in Fig. 3 for reasons such as stabilizing the process. It is necessary to form the groove 4 on the substrate 1 other than the groove 4 in the state shown in FIG. is not easy in practice.

[Object of the Invention] It is an object of the present invention to solve the above-mentioned problems and provide a technique that can form a more reliable trench isolation region in place of the conventional trench isolation formation method described above. .

Means for Solving Problem C] The device isolation region forming method of the present invention achieves the above object by adopting the following configuration.

That is, the method for forming an element isolation region of the present invention includes applying a resist onto a substrate on which an element isolation region is to be formed, exposing and developing the resist to form an overhang-shaped opening,
A groove is formed on the substrate using the resist as a mask, and then an insulating component is buried in the groove, and a groove made of the insulating component is formed on the resist, and by removing the resist, the insulating component on the resist is removed. By removing the film that forms,
By leaving an insulating component in the groove, the amount of elements that forms an isolation structure between elements is 11i1%! There is a method of forming area shadows.

The present invention will be explained as follows using the illustration of FIG. 1 showing one embodiment of the present invention which will be described in detail later.

That is, the present invention, as illustrated in FIG. 1, involves coating a resist 2 on a substrate 1 on which an element isolation region as shown in FIG. 1(a) is to be formed (FIG. 1(b)); The resist 2 is exposed and developed to form an overhang-shaped opening 3 (FIG. 1(c)). Using the resist 2 as a mask, a groove 4 is formed in the substrate 1.
(Fig. 1(d)), the insulating component 51 is formed in this
At the same time, a film 52 made of the insulating component is formed on the resist 4 to form a structure as shown in FIG. 1(e). By removing the resist 2, the film 52 that is removed from the insulating component on the resist 2 is removed, leaving the insulating component 51 in the groove 4 (FIG. 1(f)). This forms an inter-element isolation structure. In the illustrated example, the bottom of the hole was dug in the state shown in FIG. 1(f), resulting in the final structure shown in FIG. 1(g).

In the present invention, the insulating component for forming the insulating portion may be formed by a method with relatively poor step coverage (for example, resistance heating evaporation method, electron beam evaporation method, sputtering method, etc.), and the material As, Si
Among them, Si
ng is preferred.

In the present invention, an overhang-shaped opening refers to a shape in which the upper part of the opening (the part where the mouth is open) is narrow and has a part that overhangs upward like an eaves. Broadly speaking, it is sufficient that at least a part of the opening is formed to narrow the upper part of the opening.

Such overhang-shaped openings can be formed using various resist materials and appropriate means. It is preferable that the resist used be a negative type that has some absorption at the exposure wavelength. Alternatively, an image reverse type resist may be used.

Preferably, the overhang-shaped opening is formed using a chemically amplified resist, particularly an image reverse chemically amplified resist.

That is, a reverse type chemically amplified resist, for example, a chemically amplified resist containing an amine (imidazole)-based substance, is produced by forming lindene carboxylic acid with an appropriate material and causing a decarboxylation reaction after reverse exposure. , an inverted pattern with good shape can be obtained.

Furthermore, if a patterning technique using KrF laser light is adopted, the resist pattern 7 becomes a triangular pattern as shown in the extreme diagram in FIG. 2(a). Therefore, when this is reversed using the chemically amplified resist described above, an overhanging opening 9 is obtained in the resist layer 8 as shown in FIG. 2(b) (the figure is an extreme illustration).

Therefore, the present invention is suitable when a chemically amplified resist is used as the resist. Further, it is suitable for resist exposure using KrF laser light.

In addition, chemically amplified resist generally consists of Hess resin,
Although it is a 311i subsystem consisting of a photoacid generator and an acid crosslinking agent, it does not necessarily have to be a 311i subsystem. for example,
By using a compound that has a group that has the function of generating an acid when exposed to light or a group that has the function of an initiator that initiates crosslinking with the generated acid, it is possible to combine two of the three functions. It is okay to do so.

Examples of the heath resin for chemically amplified resists include vinyl resins such as polyvinylphenol. There are various types of photoacid generators, including halogen ions (e.g. BF4 e, PF6 eAsF6e, CF35O3
e, etc.), onium salts (e.g. ammonium salts, diazonium salts, iodonium salts, sulfonium salts, phosphonium salts, selenonium salts, arsonium salts, etc.), metallocene complexes, organic polyhalides (DDT, etc.), certain sulfonic acids and so on. In addition, as an acid crosslinking agent,
Examples include epoxymethylol.

The means used for exposure is arbitrary, and the exposure light is not particularly limited. For microfabrication, KrF excimer laser light (wavelength 24
8 nm, 250 nm, etc.) can be used.

For chemically amplified resists, see, for example, Ao Yamaoka and Masashi Nishikame, "New Positive Deep UV Resist," published by Breath Journal, "Monthly Sem1conductor.
It is described in Prisoner orld l, September 1988, pages 44-46.

[Function] According to the present invention, a resist pattern having an overhang-like opening is used, and the resist pattern is not removed after forming the trench on the substrate, but after filling the trench with an insulating component, the insulating component on the resist is removed. Since it is removed at the same time as the film consisting of , it is possible to easily form good element isolation.

Note that although JP-A-56-155552 discloses a lift-off technique similar to the resist removal process described above, there is no particular suggestion regarding overhang-shaped openings, and there is no particular suggestion regarding the overhang-shaped opening, The problem of etchback and the problem of etchback are not particularly suggested and are irrelevant to the present invention.

〔Example〕

Examples of the present invention will be described below.

However, it goes without saying that the present invention is not limited to the specific examples described below, and can take various forms.

Please refer to FIG.

In this example, a silicon substrate, which is a semiconductor integrated circuit board, is used as the substrate l, and a chemically amplified resist, particularly 5AL-601, which is a negative type resist, is used.
-ER7 (manufactured by Shiraplay).

Novolank resin was used as hair resin, and a photoacid generator and hexamethylolmelamine as a polymerization agent (crosslinking agent) were used. The exposure light was excimer laser light.

In this example, the above-mentioned chemically amplified negative resist was applied to a thickness of 0.7 μm on a 5-inch silicon base +H1 (FIG. 1(a)) that had been subjected to surface hydrophobization treatment.
Soft-hake for 60 seconds at °C. This results in Figure 1 (b
) structure.

Excimer laser stepper CNA: 0.37,
Pattern exposure was carried out at T: 0.5). After prebaking at 100°C for 60 seconds (pre-exposure hake), it was developed for 10 minutes with MF622 (Shinpre), a developer exclusively for 5AL601, to form an overhang pattern of 0.4 μm lines and spaces. The structure shown in Figure 1(c) was obtained.

This was etched using an etching device to form a trench (a shallow trench with a depth of 0.4 .mu.m) to form a layer 4 (FIG. 1(d)).

On top of this, 0% SiO□ was added as an insulating component by sputtering.
．． 4 μm thick, and has an insulating component 51 in the groove 4 as shown in FIG. 1(e), and a film 5 formed on the resist from the insulating component
2. This was lifted off using DMF (dimethylformamide) and acetone to form resist 2.
Then, the film 52 on which the insulating components were removed was removed, resulting in the structure shown in FIG. 1(f).

Thereafter, it was burned out at 400°C to form the trench isolation structure shown in FIG. 1(g).

Although firing was performed here, this may not be particularly necessary.

In this example, the wavelength of the light used for exposure is
A line may be used, but in that case, a negative resist is used so that an overhang shape is formed in each of the g-line and i-line regions.

As described above, in this embodiment, the grooves 4 are formed by etching from the pattern of the resist 2 having an overhang shape, and the insulating components 51 and 52 are etched in this state without removing the resist 2 after forming the grooves 4. deposited,
Element isolation is easily formed by removing unnecessary components using a lift-off method and then firing the insulating components.

As a result, element isolation of a 0.35 μm class device can be achieved satisfactorily. [Effects of the Invention] As described above, according to the present invention, a more reliable trench isolation region can be created in place of the conventional trench element isolation formation method. We can provide technology that allows for the formation of

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention in the order of steps. FIG. 2 is a diagram showing an example of forming an overhang shape. FIG. 3 shows the prior art. l...Substrate, 2...Resist, 3...Opening, 4...
...Groove, 51...Insulating component (in the groove), 52...(
A film consisting of an insulating component (on a resist). It's a dog q/) Crown map number 1, large gravity I will rise, σtsukaku> has a distribution map over/V/
Example of swimming in the shape of "carving" Dai゛ Diagram Conventional Shingho Diagram Conventional Keijutsu Diagram 3 Procedural amendment (self-motivated) January 2011 311

Claims (1)

[Claims] 1. Apply a resist onto a substrate on which an element isolation region is to be formed, expose and develop the resist to form an overhang-shaped opening, and use the resist as a mask to form a groove in the substrate. Then, an insulating component is buried in the groove, a film made of the insulating component is formed on the resist, and the film made of the insulating component on the resist is removed by removing the resist. A method for forming an isolation region between elements by leaving an insulating component to form an isolation structure between elements.