JPH07235481A - Deposition of thin film - Google Patents

Abstract

PURPOSE:To deposit a thin film uniformly on a substrate by mixing a gasified catalyst and a monomer and then feeding the mixture into a reactor. CONSTITUTION:After a basic material, i.e., a silicon wafer 11, is arranged on a susceptor 4, exhaust valves 5, 10 are opened to evacuate a reactor 1 and a gas mixer 9. Upon reaching a predetermined pressure, the exhaust valves 5, 10 are closed. A gas valve 6 is then opened to feed a catalyst through a gas mixer 9 at a predetermined flow rate and after closing the gas valve 6, a gas valve 7 is opened to feed the mixer 9 with a monomer at a predetermined flow rate before the gas valve 7 is closed. In other words, a catalyst and a monomer are fed into the gas mixer 9 where they are mixed each other. Subsequently, a gas supply valve 11 is opened to feed the reactor 1 with a mixture of catalyst and monomer thus depositing a thin film uniformly on the silicon wafer 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thin film, and more particularly to a method for producing an underlayer thin film for a radiation sensitive resist, and further to reduce radiation reflection from a substrate in a lithography process in semiconductor production. Therefore, it is suitable as a method for producing an underlayer thin film for a radiation-sensitive resist that gives a resist pattern that is fine and has stable processability.

[0002]

2. Description of the Related Art In the manufacture of semiconductors, with the increase in capacity of semiconductor memories, finer processing techniques continue to be required. A lithography technique is generally used for the fine processing.

Here, a general lithography technique will be described. A radiation-sensitive resist is formed on a semiconductor substrate, and radiation is selectively irradiated so that a desired resist pattern can be obtained, and then development is performed to form a 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.

Currently, a resist pattern having a size of about 0.5 μm is being industrially put into practical use.
Further miniaturization is required. As a method of miniaturizing the resist pattern, for example, there is a method of pattern exposure by using light of a single wavelength as radiation and reducing and projecting the original image. Especially for the purpose of microfabrication, it is required to shorten the wavelength of light, and the technology of irradiating with a wavelength of 436 nm has already been established.
Development of a technique for irradiating with light in the deep ultraviolet region of m or less is under study.

Such a lithographic technique has the following problems. First, radiation interference occurs in the radiation-sensitive resist film due to reflection from the base material, and as a result, the amount of energy of radiation applied to the radiation-sensitive resist film due to fluctuations in the thickness of the radiation-sensitive resist film. Will have varying characteristics. That is, the dimension of the resist pattern obtained by the minute change in the thickness of the radiation-sensitive resist is likely to change. Further, as the wavelength of the radiation is shortened for the purpose of making the processing finer, the radiation reflection from the substrate generally increases, and this characteristic becomes remarkable. The change in the thickness of the resist layer is caused by characteristic changes of the radiation-sensitive resist material due to aging or difference between lots, and changes in the coating conditions of the radiation-sensitive resist. Changes in thickness. As described above, the dimensional change of the resist pattern due to the change of the thickness of the resist layer reduces the process tolerance at the time of manufacturing, which is an obstacle to finer processing.

Further, when the base material is highly reflective and the steps are arranged in a complicated manner, diffuse reflection of radiation occurs, so that the desired resist pattern shape tends to locally change. There's a problem.

In order to solve such a problem, a method of suppressing reflection on a base material has been proposed, and the present inventors have already proposed, as one method for suppressing the above reflection, JP-A-5-45873. Japanese Patent Laid-Open Publication No. 9-242242 proposes a method of interposing a thin film containing a conjugated polymer as a main component between a substrate and a radiation-sensitive resist.

[0008]

As a method for producing such a conjugated polymer, in Japanese Patent Application No. 5-6123, a catalyst and a monomer which are vaporized in a state where the pressure of the reactor is reduced and then the exhaust is stopped. We proposed a method of forming a thin film on a substrate by feeding In this manufacturing method, since the film formation is performed with the exhaust gas stopped, the usage efficiency of the monomer as a raw material is high, but as a method for further improving the usage efficiency, Japanese Patent Application No. 5-345145 proposes a method of reducing the reaction vessel. did. With this method, the amount of monomer used could be reduced by making the container smaller, but as a result of subsequent studies,
It has been found that when the container is too small, unevenness in film thickness may occur in the surface of the substrate.

An object of the present invention is to solve the drawbacks of the prior art, and it is an object of the present invention to provide a method for producing a thin film in which the usage efficiency of the monomer is high and the film thickness of the thin film is small.

[0010]

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

"In a method for supplying a vaporized catalyst and a monomer into a reactor to produce a thin film on a substrate, the catalyst and the monomer are mixed and then supplied to the reactor. A method for manufacturing a thin film. ”Hereinafter, the present invention will be described in detail. First, the thin film shown in the present invention will be described. The use of the thin film of the present invention is not particularly limited, but it is particularly useful as an underlayer film of a two-layer structure radiation sensitive resist. For example, a thin film is formed on the base material by the method shown in the present invention to form a lower layer film.
Further, an upper layer resist which is sensitive to radiation and can form a pattern is formed on the thin film to obtain a two-layer structure radiation sensitive resist. Then, patterning radiation is irradiated, and then a developing operation is performed to form a pattern of the upper layer resist. Next, by using the upper layer resist as a mask, the lower layer resist in the opening of the upper layer resist is removed by dry etching, and the two-layer structure radiation sensitive resist is patterned.

Here, as the radiation for pattern formation,
Although arbitrarily selected in the lithography technique, the lower layer resist comprising the thin film of the present invention is particularly effective for electromagnetic waves, that is, light, and particularly electromagnetic waves having a wavelength of 150 nm or more are effective. For example, the wavelength is about 436n
m, about 405 nm, about 365 nm, about 254 nm, etc., mercury lamp emission line, about 364 nm, about 248 nm, about 193 n
m laser light and the like.

In the present invention, the monomer forming the thin film is not particularly limited, but an ethylene compound or an acetylene compound having a polymerizable unsaturated bond is particularly preferably used. Among these compounds, a cyano group, from the viewpoint of polymerizability (film formation) in the method of the present invention,
Those having an electron-withdrawing group such as an amide group, an oxycarbonyl group, a nitro group and a halogen atom bonded to carbon having an unsaturated bond are preferably used.

Further, among the ethylene compounds, compounds having a cyano group as a substituent are preferable, and vinylidene cyanide, α-chloroacrylonitrile, cyanoacrylate compounds and their derivatives are exemplified. For the same reason, among the acetylene compounds, a compound having a cyano group, an amide group and an oxycarbonyl group is preferably used, and cyanoacetylene, an alkyl propiolate, an alkyl tetrol acid, an N, N-dialkylpropiolic acid amide, Examples are nitroacetylene and their derivatives.

The catalyst used in the production method of the present invention is arbitrary as long as it can form the above-mentioned thin film,
From the viewpoint of vaporization of the material in the method of the present invention and avoidance of adverse effects on the substrate (particularly on semiconductor properties), nonmetallic compounds are preferably used, and examples thereof include nitrogen-containing organic compounds, ether compounds, thioether compounds. Compound, phosphorus compound,
Water etc. can be raised. Of these, nitrogen-containing organic compounds are preferably used from the viewpoints of vaporizability and polymerization (film formation) efficiency. Of these, tertiary amino compounds such as trimethylamine, triethylamine, tributylamine and N, N-dimethylaminopyridine are preferably used.

The substrate used in the present invention is arbitrarily selected, but the present invention is particularly effective in the manufacturing process of semiconductor integrated circuits. In that case, silicon, germanium, gallium compound, indium compound, etc. Illustrative examples of the base material having the semiconductor characteristics of, or those obtained by coating these base materials with an impurity diffusion, a nitride, an oxide, an insulating film, a conductive layer, an electric wiring, and the like.

The present invention is also effective as a method for producing a light-shielding film for a liquid crystal display. In this case, for example, a transparent substrate such as glass or glass is processed with a metal, a semiconductor or the like. Things can be used.

The method for producing a thin film of the present invention will be described below with reference to the drawings. FIG. 1 is an example of a schematic diagram of an apparatus for carrying out the manufacturing method of the present invention. In FIG. 1, 1 is a reactor, 2 is a container containing a catalyst, 3 is a container containing a monomer, and 4 is a susceptor. Further, 5 is an exhaust valve, 6 is a gas valve for supplying a catalyst, 7 is a gas valve for supplying a monomer, and 8 is a gas valve for supplying an inert gas. Reference numeral 9 is a gas mixer for mixing the catalyst and monomer, and 10 is a gas supply valve for supplying the mixed catalyst and monomer.

After arranging a substrate such as a silicon wafer on the susceptor 4, the reactor 1 and the gas mixer 9 are exhausted by an exhaust device (not shown) by opening the exhaust valve 5 and the gas supply valve 10 to reduce the pressure. . When the predetermined pressure is reached, the exhaust valve 5 and the gas supply valve 10 are closed.

Next, a gas valve 6 for supplying a catalyst
The gas mixer 9 is opened and a predetermined flow rate of catalyst is supplied. The gas valve 6 for supplying the catalyst is closed, the gas valve 7 for supplying the monomer is opened, the monomer having a predetermined flow rate is supplied to the gas mixer 9, and then the gas valve 7 for supplying the monomer is closed. In this way, the catalyst and the monomer are supplied to the gas mixer to mix these gases. Then, the gas supply valve 10 is opened to supply a mixed gas of the catalyst and the monomer into the reactor 1 to obtain a thin film on the substrate 11.

The flow rates of the catalyst and monomer are measured and controlled by, for example, mass flow meters 12 and 13. In order to improve the utilization rate of the monomer, it is preferable to heat the gas mixer 9 and the gas supply pipe from the gas mixer 9 to the reactor 1 and the valves in this path after heating. By heating and raising the temperature of these portions, it is possible to prevent film formation in the gas mixer and the supply pipe portion, and it is possible to increase the utilization rate of monomers. Any heating means such as a commercially available tape heater and ribbon heater can be used to heat the gas mixer. Reference numeral 14 is a temperature control mechanism of the heating means. The heating temperature may be higher than the temperature at which the catalyst and the monomer are not adsorbed on the wall surface of the pipe. This temperature cannot be generally stated because it depends on the raw materials, but as an example, when triethylamine is used as the catalyst and cyanoacetylene is used as the monomer, it is 3
The temperature is preferably 5 ° C or higher, more preferably 40 ° C or higher.

The ultimate pressure of the reactor before supplying the catalyst and monomer is preferably 1 Torr or less, and further 10 ^-1 Torr or less so that impurities in the atmosphere such as moisture do not adversely affect the film formation rate. desirable.

The pressure inside the reactor when supplying the catalyst and the monomer is preferably more than 1 Torr. 1 To
When it is rr or less, the film forming rate tends to be slow, and more preferably in the range of 10 Torr to 500 Torr.

Reference numeral 15 denotes a ring-shaped gas supply nozzle having a large number of fine holes, which is connected to the catalyst and monomer gas supply pipes. Reference numeral 16 is a pressure gauge for the reactor 1.

A thin film is formed by the above method, and with the gas supply valve 10 opened, the exhaust valve 5 is opened to exhaust the catalyst and monomer gas remaining in the reactor 1 to form a thin film. Finish. After exhausting for a predetermined time, the exhaust valve 5 and the gas supply valve 10 are closed to stop the exhaust. The gas valve of No. 8 is opened, and an inert gas such as nitrogen is supplied into the reactor to return the inside of the reactor 1 to normal pressure.

It is preferable that the temperature of the susceptor 4 is controlled by the temperature control mechanism 17 or the like to set and maintain the base material at a constant temperature. The temperature of the susceptor 4 is preferably low so that the catalyst or monomer is adsorbed on the base material. When the temperature is high, the film formation rate is significantly reduced, and when the susceptor temperature is too low, the catalyst and the monomer are condensed. The temperature of the susceptor varies depending on the raw material used and cannot be generally stated. However, when triethylamine is used as the catalyst and cyanoacetylene is used as the monomer, the temperature range is preferably 5 to 35 ° C.

The container for the catalyst and the monomer is a thermostatic chamber 18,
It is desirable to keep the vapor pressure constant at 19 or the like in order to control the film formation rate. Reference numerals 20 and 21 are temperature control mechanisms for the constant temperature bath.

Further, the catalyst and the monomer are supplied in a gaseous state into the reactor, but in order to uniformly supply the gas to the substrate,
As described above, the ring-shaped gas blowing nozzle 15 having a large number of fine holes is arranged in the vicinity of the base material, or a gas supply plate having a large number of fine holes in the portion of the reactor facing the base material is provided. It is also preferable to arrange them or to provide a fine opening in the peripheral portion of the base material above the susceptor.

Prior to forming a thin film by the manufacturing method of the present invention, for improving the adhesion between the substrate and the thin film,
It is also preferable to subject the substrate to heat treatment, plasma treatment or other surface treatment.

The production method of the present invention is particularly effective when the reactor volume is small, and in particular, the height from the substrate surface seems to have a greater effect than the volume, and the reaction with a height of 20 mm or less is performed. In the container, the effect on the film thickness uniformity is great. It is estimated that when the height is 20 mm or less, when the catalyst and the monomer are separately supplied, the film thickness varies due to the difference in the time required for the catalyst and the monomer to reach the substrate surface. As described in the present invention, even if the reactor is made small by supplying both the catalyst and the monomer after mixing them in advance, uneven film thickness does not occur in the surface of the substrate.

[0031]

【Example】

Examples 1 to 3 and Comparative Examples 1 to 3 Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples using the apparatus of FIG. However, as the gas supply port in the reactor 1, one having a circular fine port provided in the peripheral portion of the base material above the susceptor was used. The height of the reactor is 30 mm, 2
Table 1 shows Examples and Comparative Examples in which thin films were obtained by changing to 0 mm and 2 mm. By the production method of the present invention using a gas mixer,
Example 1 in which a catalyst and a monomer gas were mixed and supplied,
Examples 2 and 3 are comparative examples 1, 2 and 3 in which the catalyst and the monomer gas are sequentially supplied to the reactor without using the gas mixer. A 6-inch size silicon wafer was used as a substrate. In Table 1, an example in which the film thickness distribution at the 9 points within the substrate surface is within ± 5% is indicated by a circle. However, in the method of the present invention, the in-plane film thickness distribution is shown even when the reactor is made small. It was uniform. The film thickness was measured with a surface roughness meter. The temperature of the susceptor during film formation was kept constant at 20 ° C.

[0032]

[Table 1] Examples 4 to 5 and Comparative Example 4 Next, as Example 4, in the case where the gas mixer was heated and raised, and in Example 5, when the gas mixer was not heated and raised, and as Comparative Example 4, Example 4 was performed. Shows the utilization rate of each monomer when the gas mixer is not used. In the apparatus shown in FIG. 1, a reactor having a height of 2 mm was used. In both Example 4 and Example 5, the catalyst supply amount was 3 ml and the monomer supply amount was 15 ml to the gas mixer, and then the mixed gas was supplied to the reactor to form a thin film having a film thickness of 2000 A on a 6-inch silicon wafer. Got In Comparative Example 4, the catalyst and the monomer gas were sequentially supplied without using the gas mixer.

In Comparative Example 4, the utilization rate of the monomer was about 3%, whereas in Example 5, the utilization rate was greatly improved to 8%. In Example 4 in which the mixer was heated, the utilization rate was 14%. Is
Further improved.

[0034]

By the production method of the present invention, that is, by mixing the catalyst and the monomer and supplying them to the reactor, the in-plane film thickness uniformity of the obtained thin film is excellent.

In particular, to improve the utilization rate of the monomer by heating and elevating at least the catalyst, the mixed portion of the monomer and the gas supply path from the mixed portion to the reactor in the vaporized catalyst and monomer supply pipes. You can

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional schematic view of an example of an apparatus for carrying out the manufacturing method of the present invention.

[Explanation of symbols]

 1: Reactor 2: Catalyst 3: Monomer 4: Susceptor 5: Exhaust valve 6: Gas valve for supplying catalyst 7: Gas valve for supplying monomer 8: Gas valve for supplying inert gas 9: Gas mixture Container 10: Gas supply valve 11: Base material 12, 13: Mass flow meter 14: Temperature control mechanism for gas mixer and piping 15: Gas supply nozzle 16: Pressure gauge 17: Temperature control mechanism for susceptor 18, 19: Constant temperature bath 20 , 21: Temperature control mechanism for catalyst and monomer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G03F 7/26 511 H05K 3/06 F

Claims (4)

[Claims] 1. A method of supplying a vaporized catalyst and a monomer into a reactor to produce a thin film on a substrate, wherein the catalyst and the monomer are mixed and then supplied to the reactor. A method for manufacturing a thin film. 2. The method for producing a thin film according to claim 1, wherein the mixed catalyst and monomer are heated and then supplied to a reactor. 3. The method for producing a thin film according to claim 1, wherein the monomer is an ethylene compound or an acetylene compound. 4. The method for producing a thin film according to claim 1, wherein the thin film is used as a resist.