JPH06116305A - Production of thin film - Google Patents

Abstract

PURPOSE:To obtain a thin film suitable as a double-layer resist for forming a desired pattern by contacting a substrate with a compound having tertiary amino group and contacting with a reactive monomer to effect the polymerization of the monomer. CONSTITUTION:A substrate (e.g. silicon or an indium compound) is placed in a reaction vessel and made to contact with (A) a compound having tertiary amino group and having a boiling point of >=110 deg.C under normal pressure in gaseous or liquid state. The substrate is then made to contact with (B) a reactive monomer, preferably a substituted acetylene compound, especially preferably cyanoacetylene in vapor phase to effect the polymerization of the monomer and obtain the objective thin film suitable as the lower layer film of a resist having a double-layer structure. This thin film is effective in suppressing the reflection, etc., of radiation and suitable for forming a desired pattern by micro- processing in the production of semiconductor device.

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 thin film, and is particularly suitable as a method of manufacturing a thin film for improving the degree of integration and yield in a lithography process in a fine processing process for manufacturing a semiconductor.

[0002]

2. Description of the Related Art In the field of semiconductor manufacturing, with the increase in capacity of semiconductors, finer processing techniques are required to increase the degree of integration. Lithography technology is used for the fine processing.

Here, a general lithography technique will be described. A photosensitive resist is formed on the semiconductor substrate to form a desired resist pattern. Using the resist pattern as a mask material, processes such as etching, ion implantation and vapor deposition are performed, and these steps are repeated to manufacture a semiconductor.

The size of the resist pattern is currently 0.5 μ
M-type devices are being put to practical use industrially, and VLSI
Further miniaturization is required for the miniaturization.

As a method of miniaturizing the resist pattern, there is a method of performing pattern exposure by using light of a single wavelength and reducing and projecting the original image. In particular, it is required to shorten the wavelength of light used for the purpose of microfabrication, and the technology of irradiating with a wavelength of 476 nm has already been established.
Development and study of a technique of irradiating with light in the deep ultraviolet region of 00 nm or less is under way.

There are the following problems in such a lithographic technique. First, due to reflection from the substrate, radiation interference occurs in the radiation-sensitive resist film,
As a result, the amount of radiation energy applied to the resist film changes due to the change in the thickness of the radiation-sensitive resist.
That is, the dimensions of the obtained resist pattern are likely to change. Further, as the wavelength of radiation is shortened for the purpose of fine processing, radiation reflection from the substrate generally increases,
Such a variation becomes remarkable. Further, the change in the thickness of the resist layer is caused by the aging of the radiation-sensitive resist material, the difference between lots, and the coating conditions, and is also caused by the step difference of the substrate. Thus, the dimensional change of the resist pattern due to the change of the thickness of the resist layer is an obstacle to finer processing.

Further, when the reflection of the substrate is large and the steps are arranged in a complicated manner, diffuse reflection of radiation occurs, so that a portion different from the desired resist pattern is likely to occur.

In order to solve such a problem, a method of suppressing reflection on the substrate is proposed. For example, there is a method in which a low-reflectance inorganic compound is vapor-deposited on a substrate to form an antireflection film, and then a lithography process is performed. However, since it is an inorganic compound, there is a drawback that the peeling process becomes complicated. Further, some of the semiconductor processes are concerned with the influence on the semiconductor characteristics and such treatment is not permitted, and this method is used only for a limited number of processes.

Further, for example, in JP-A-63-138353, a film of an antireflection organic material which is composed of a resin and a radiation absorber and which is soluble in the developer of the radiation sensitive resist of the upper layer is arranged in the lower layer. A double structure resist having a radiation sensitive resist as an upper layer is formed, and after irradiation with radiation, the upper layer is patterned by a developing operation, and at the same time, the lower layer is also developed using the opening of the pattern of the upper layer obtained by the development as a mask. A method for obtaining a resist pattern has been proposed.
However, in this technique, the dissolution rates of the upper layer and the lower layer with respect to the developing solution are generally different, so that the lower layer portion is easily undercut, and a resist pattern that remains in a hem is easily obtained, and it is difficult to control the process. was there.

In addition, after an organic compound is used as a lower layer and a resist containing an inorganic compound such as silicon is coated as an upper layer or an intermediate layer, a layer containing an inorganic compound is formed into a pattern, and the pattern is used as a mask to form a lower layer from a pattern opening. A two-layer or three-layer resist method has been proposed in which a resist pattern is formed by anisotropic etching.
With this method, the problem of the pattern shape is less likely to occur, but the peeling process becomes difficult because an inorganic compound is used.

[0011]

SUMMARY OF THE INVENTION As described above, it is an object of the present invention to provide a method for producing a thin film which is suitable for forming a desired pattern by suppressing reflection of radiation.

[0012]

In order to achieve the above object, the present invention has the following constitution.

The present invention will be described in detail below.

"The boiling point at atmospheric pressure is 110 ° C. on the substrate.
The method for producing a thin film, which comprises contacting a compound having a tertiary amino group, and then contacting a reactive monomer to polymerize. The thin film of the present invention is preferably used as a lower layer film of a resist, and subsequently, by forming a resist having radiation sensitivity or the like, it is preferably used as a two-layer structure resist.

As a pattern forming process using a two-layer structure resist, first, a compound having an amino group having a boiling point of 110 ° C. or higher at atmospheric pressure is brought into contact with a substrate, and then a reactive monomer is brought into contact therewith. A thin film (hereinafter referred to as the lower layer film) is formed by polymerization, and subsequently, for example, a radiation-sensitive resist is formed (hereinafter referred to as the upper layer resist) to form a two-layer structure resist, which is then irradiated with radiation, A developing operation is performed to form a pattern of the upper layer resist. Further, by using the upper layer resist as a mask, the lower layer film of the opening of the upper layer resist is removed by etching to form a resist pattern having a two-layer structure.

The substrate used in the present invention is not particularly limited, but it is preferably selected arbitrarily from the materials used in the lithography process. INDUSTRIAL APPLICABILITY The present invention can exert effects particularly in the manufacturing process of semiconductor integrated circuits, and for example, a substrate having semiconductor characteristics such as silicon, germanium, gallium compound, indium compound,
Or to these substrates, impurity diffusion, nitrides, oxides,
A preferable substrate is one in which an insulating film, a conductive layer, wiring and the like are processed. Further, it is also effective in the manufacturing process of photomasks and flat panel displays, and for example, those obtained by processing a metal thin film semiconductor on a transparent base material such as glass are preferably used.

In the lower layer film of the present invention, any compound having a tertiary amino group and having a boiling point of 110 ° C. or higher at atmospheric pressure, that is, at 1 atmospheric pressure is used without particular limitation. When the boiling point is 110 ° C. or higher, contamination in the polymerization system is prevented, which is preferable. When a catalyst having a temperature of less than 110 ° C. is used, the catalyst is likely to volatilize, so that the polymer adheres to the portion other than the substrate in the chamber for film formation, resulting in significant contamination of the system. The use of a compound having a tertiary amino group is also preferable in that a robust film can be obtained.

Examples of the compound having a tertiary amino group include tripropylamine, tributylamine, trihexylamine, pyridine, 4-aminodimethylpyridine, triethylenediamine, N, N, N ', N'-tetramethylethylenediamine and dimethyl. Amino ethanol, 3- (N, N-dimethylaminopropyltrimethoxysilane) and the like are used.

Examples of the method of contacting the compound having a tertiary amino group include a method of contacting the compound in a liquid state and a method of contacting the compound in a gas state. As a method of contacting in a liquid state, for example, a method of applying the solution onto a substrate by a method such as spin coating and vaporizing the solution to bring the compound into contact with the substrate is used. Further, as a method of bringing the compound into contact in a gaseous state, bubbling with an inert gas from a container containing the compound, vaporization by heating the compound, vaporization by reducing the pressure in the container, etc. A method of bringing the gas of the compound into contact with the substrate is used.

Next, the reactive monomer is preferably a monomer capable of forming a conjugated polymer among organic materials.
Of these, substituted acetylene polymers are preferable. Polycyanoacetylene is more preferable in terms of optical characteristics, that is, low reflectance.

As a method of forming the lower layer film, there are a method of applying a polymer solution and a method of polymerizing on a substrate to form a polymer layer. When the substrate has steps, a method of directly polymerizing on the substrate is preferable in order to cover the steps faithfully. As the polymerization method, a monomer is supplied onto a substrate treated with a catalyst, a method of obtaining a thin film by polymerization, plasma polymerization,
Thermal polymerization is mentioned. Above all, polymerization using a catalyst having a simple process apparatus is preferable.

The upper layer resist is used for semiconductor manufacturing,
Radiation-sensitive resists used in the field of photolithography such as printed circuit boards are used without particular limitation. For example, X-ray resists, electromagnetic wave resists such as photosensitive resists, electron beam resists, ion beam resists, etc. Is used. Among them, any radiation-sensitive resist capable of forming a pattern by the process of development is preferably used. Resist, a so-called chemically amplified radiation-sensitive resist consisting of a compound that generates an acid upon irradiation with radiation and a compound whose molecular weight fluctuates or is converted into a functional group, and other molecular weight increases or decreases upon irradiation with radiation. A radiation-sensitive resist composed of a compound capable of reacting a functional group of a compound or a compound is preferably used. As the radiation for irradiating the pattern, electromagnetic waves, that is, light is preferably used, and electromagnetic waves having a wavelength of 150 nm or more are particularly effective. For example, the wavelength is about 436nm, about 405n
m, about 365 nm, about 254 nm mercury lamp emission line, about 36
Laser light of 4 m, about 248 nm, about 193 nm and the like can be mentioned.

As an electron beam, 1 KeV to 100
Those having an energy of KeV are preferably used.

Hereinafter, the present invention will be described more specifically with reference to examples.

[0025]

【Example】

Example 1 A silicon wafer substrate was placed in a reaction vessel, nitrogen gas was introduced as a carrier gas, tributylamine was introduced as a catalyst, and cyanoacetylene was introduced as a monomer into the reaction vessel. The amount of carrier gas was 150 ml / min of catalyst and 300 ml / min of monomer. The polymerization reaction proceeded by this method, and a thin film having a thickness of 4000 A was formed on the silicon wafer. The reflectance (incident angle: 12 °) of the substrate on which the cyanoacetylene polymer thin film was formed was measured by a Hitachi recording spectrophotometer (U-3410).
It was about 5% in the wavelength range of 0 nm to 700 nm. Polymerization occurred only slightly on the wall surface of the reaction vessel, and the contamination of the reaction system was slight.

Example 2 A silicon wafer substrate was placed in a reaction vessel, a tributylamine solution as a catalyst was spin-coated and applied in the reaction vessel, and cyanoacetylene monomer was introduced as a carrier gas of nitrogen gas and brought into contact therewith. . Carrier gas amount is 30
It was set to 0 ml / min. The polymerization reaction proceeded by this method, and a thin film having a thickness of 5000 A was formed on the silicon wafer. The reflectance (incident angle 12 °) of the substrate on which the cyanoacetylene polymer thin film was formed was measured with a Hitachi spectrophotometer (U-3410), and it was 500 nm to
It was about 5% in the wavelength range of 700 nm. The boiling point of tributylamine was 212 ° C. at 9 mmHg, polymerization did not occur on the wall surface of the reaction vessel, and contamination of the system by the polymer was not observed.

Example 3 A silicon wafer substrate was placed in a reaction vessel, and N, N, N ', N'-tetramethylethylenediamine solution as a catalyst was spin-coated and applied in the reaction vessel, and nitrogen gas was used as a carrier gas. Introduce cyanoacetylene monomer as
Contacted. The carrier gas amount was 300 ml / min. The polymerization reaction proceeded by this method, and a thin film with a thickness of 6000 A was formed on the silicon wafer. The reflectance of the substrate on which the cyanoacetylene polymer thin film is formed (incident angle 1
2 °) made by Hitachi Ltd. self-recording spectrophotometer (U-3410)
Was about 5% in the wavelength range of 500 nm to 700 nm. The boiling point of N, N, N ′, N′-tetramethylethylenediamine was 125 ° C., polymerization did not occur on the wall surface of the reaction vessel, and the contamination of the system by the polymer was slight. This film had solvent resistance to acetone and dimethylformamide.

Example 4 A silicon wafer substrate was placed in a reaction vessel, a 2% dioxane solution of 4-dimethylaminopyridine was applied to the reaction vessel by spin coating as a catalyst, and cyanoacetylene monomer was introduced using nitrogen gas as a carrier gas. And contacted. The carrier gas amount was 300 ml / min. The polymerization reaction proceeded by this method, and a thin film having a thickness of 5000 A was formed on the silicon wafer. When the reflectance (incident angle 12 °) of the substrate on which the cyanoacetylene polymer thin film was formed was measured with a Hitachi recording spectrophotometer (U-3410), it was about 5% in the wavelength range of 500 nm to 700 nm. Met. Polymerization did not occur on the wall surface of the reaction vessel, and no contamination of the system by the polymer was observed.

Example 5 A silicon wafer substrate was placed in a reaction vessel, spin coating was performed in the reaction vessel using pyridine as a catalyst, and a cyanoacetylene monomer was introduced and brought into contact with nitrogen gas as a carrier gas. Carrier gas amount is 300 ml / min
And The polymerization reaction proceeded by this method, and a liquid thin film was formed on the silicon wafer. When the film was heated in an air oven at 80 ° C., a solid film having a film thickness of 4000 A was formed. The reflectance (incident angle 12 °) of the substrate on which the cyanoacetylene polymer thin film was formed was measured by a Hitachi recording spectrophotometer (U-3410), and it was 500 nm.
It was about 5% in the wavelength range of ~ 700 nm. The boiling point of pyridine was 116 ° C., polymerization did not occur on the wall surface of the reaction vessel, and contamination of the system by the polymer was not observed.

Example 6 A silicon wafer substrate was placed in a reaction vessel, and nitrogen gas was introduced as a carrier gas into tributylamine as a catalyst and cyanoacetylene as a monomer, respectively. Carrier gas volume is 150 ml / min catalyst, 300 ml monomer
/ Min. The polymerization reaction proceeded by this method, and a thin film having a thickness of 4000 A was formed on the silicon wafer.
The reflectance (incident angle 12 °) of the substrate on which the cyanoacetylene polymer thin film was formed was measured by Hitachi's own spectrophotometer (U-
3410), 500 nm-700 n
It was about 5% in the wavelength range of m.

On the substrate on which the lower layer film is formed, Toray Co., Ltd.
A photoresist "PR-alpha" 2000 produced was spin-coated and then baked on a hot plate at 100 ° C. for 60 seconds to form an upper layer resist. (stock)
Using the Nikon i-line (wavelength 365 nm light) stepper,
After pattern exposure, on a hot plate at 120 ° C, 6
Bake for 0 seconds. Subsequently, by developing with a 2.4% aqueous solution of tetramethylammonium hydroxide, an upper resist pattern was formed.

Next, anisotropic etching of the lower layer film was performed with oxygen plasma using the upper layer resist pattern as a mask. As a result, a two-layer structure resist pattern having an excellent pattern shape was obtained.

Example 7 A silicon wafer substrate having a step difference made of aluminum was placed in a reaction vessel, and nitrogen gas was used as a carrier gas in the reaction vessel.
Tributylamine was introduced as a catalyst, and cyanoacetylene was introduced as a monomer. The amount of carrier gas is catalyst 15
The amount was 0 ml / min and the monomer was 300 ml / min. The polymerization reaction proceeded by this method, and a thin film having a thickness of 2000 A was formed on the silicon wafer. When the substrate on which the cyanoacetylene polymer thin film was formed was observed with a scanning electron microscope, it was found that the steps were well covered with a uniform film thickness.

Example 8 A silicon wafer substrate was placed in a reaction vessel, and a 2% tetrahydrofuran solution of N, N-dimethylaminopropyltrimethoxysilane was applied as a catalyst in the reaction vessel by spin coating, and nitrogen gas was used as a carrier gas. The cyanoacetylene monomer was introduced and brought into contact. Carrier gas amount is 3
It was set to 00 ml / min. The polymerization reaction proceeded by this method. After heating at 100 ° C. for 30 minutes, a thin film having a thickness of 3000 A was formed on the silicon wafer. The reflectance of the substrate on which the cyanoacetylene polymer thin film is formed (incident angle 12
Was measured with a Hitachi spectrophotometer (U-3410), which was about 5% in the wavelength range of 500 nm to 700 nm. Polymerization did not occur on the wall surface of the reaction vessel, and no contamination of the system by the polymer was observed.

Comparative Example 1 A silicon wafer substrate was placed in a reaction vessel, nitrogen gas was used as a carrier gas, and triethylamine was introduced as a catalyst, and cyanoacetylene was introduced as a monomer into the reaction vessel. The amount of carrier gas was 150 ml / min of catalyst and 300 ml / min of monomer. The polymerization reaction proceeded by this method, and a thin film having a thickness of 5000 A was formed on the silicon wafer. The reflectance (incident angle 12 °) of the substrate on which the cyanoacetylene polymer thin film was formed was measured by a Hitachi recording spectrophotometer (U-3410), and the result was 500.
It was about 5% in the wavelength range of nm to 700 nm. However, polymerization also occurred on the wall surface of the reaction vessel, and a black polymer was deposited in the same thickness as the substrate.

[0036]

According to the present invention, it is possible to provide a method for producing a thin film suitable for use as a two-layer structure resist for forming a desired pattern, and particularly, it is possible to eliminate contamination in the chamber. .

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // C08F 38/00 MPU 8416-4J

Claims (4)

[Claims] 1. A method for producing a thin film comprising contacting a compound having a tertiary amino group having a boiling point of 110 ° C. or higher at atmospheric pressure on a substrate, and then contacting a reactive monomer to polymerize the compound. Method. 2. The method for producing a thin film according to claim 1, wherein the reactive monomer is cyanoacetylene. 3. The method for producing a thin film according to claim 1, wherein the reactive monomer is brought into contact with the substrate in a gaseous state. 4. The method for producing a thin film according to claim 1, wherein the compound having an amino group is brought into contact with the substrate in a gas or liquid state.