JPH10303183A - Method of forming pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a reliable semiconductor superior in characteristic by transferring a pattern similar to the pattern formed on organic films to the substrate. SOLUTION: A reaction product 16 is formed by etching an organic antireflection film 14 by using gas containing chlorine and the product is wholly coated by fluorocarbon polymer film 38. Owing to the coating, when the Si wafer 11 is exposed to the air, the fluorocarbon polymer film 38 prevents water in the air from entering the reaction product 16 and the volume of the reaction product 16 does not expand because of no reaction between chlorine in the reaction product and the water in the air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a pattern in which a pattern is formed on an organic anti-reflection film or the like and then transferred to a base such as a conductive film in manufacturing a semiconductor device. .

[0002]

2. Description of the Related Art In manufacturing a semiconductor device, a pattern is formed on a photoresist by photolithography. In an exposure process in photolithography, a part of light incident on the photoresist is reflected at an interface with a base and interferes with the incident light. It is known that a standing wave effect is caused by performing the operation. In addition, a step is generally already formed on the underlayer of the photoresist, and the thickness of the photoresist varies depending on the position on the wafer.

For this reason, the effect of the standing wave effect also differs depending on the position on the wafer, and it is impossible to form a wiring having a desired line width. Therefore, as one method of reducing the standing wave effect, a method of forming an antireflection film under a photoresist has been considered. As the anti-reflection film, an organic anti-reflection film that can contain a dye that absorbs light having the wavelength used in the exposure step and can completely prevent reflection from the base is often used. ing.

On the other hand, when an anti-reflection film is formed under a photoresist, it is necessary to pattern the anti-reflection film prior to etching a base using the photoresist as a mask. Gas containing oxygen is mainly used for processing the organic anti-reflection film.However, in order to reduce the conversion difference between the photoresist patterned by photolithography and the organic anti-reflection film, chlorine is used. It has been proposed to use a gas containing gas (Preprint of the 57th Annual Conference of the Japan Society of Applied Physics, No.2 p.483, Lecture No. 7a-T-1).

FIG. 4 shows a conventional example of the present invention in which an organic antireflection film and a polycrystalline Si film are patterned by using such a gas. In this conventional example, FIG.
As shown in (a), a SiO ₂ film 12 is formed on a Si wafer 11.
And a polycrystalline Si film 13 containing phosphorus as an impurity are sequentially formed, and an organic antireflection film 14 (for example, Brewer Science) is formed.
DUV-18) is spin-coated on the polycrystalline Si film 13 so that the flat portion has a thickness of 150 nm.

Then, a photoresist 15 is coated on the organic antireflection film 14, and the photoresist 15 is formed into a pattern having a width of 0.25 μm by exposure and development using a reduction projection exposure apparatus for irradiating an excimer laser beam. Process. Thereafter, as shown in FIG. 4B, the organic anti-reflection film 1 was formed using an ECR type etching apparatus under the following conditions.
4 is etched.

Gas: O ₂ / Cl ₂ = 40/40 SCCM Pressure: 1.0 Pa Microwave output: 1200 W High frequency bias: 100 W (800 kHz) Wafer temperature: −20 ° C. Etching amount: 200 nm

Next, as shown in FIG. 4C, the Si wafer 11 is taken out from the ECR type etching apparatus in which the organic anti-reflection film 14 is etched, and another ECR is formed as shown in FIG. The polycrystalline Si film 13 is etched using a photoresist 15 as a mask under the following conditions using a mold type etching apparatus.

Gas: O ₂ / Cl ₂ = 2/150 SCCM Pressure: 1.0 Pa Microwave output: 1200 W High frequency bias: 100 W (800 kHz) Wafer temperature: −20 ° C.

[0010]

However, FIG. 4 (b)
As shown in (1), the underlying polycrystalline Si film 13 is sputtered while the organic anti-reflection film 14 is over-etched, and the reaction product 16 adheres to the side surfaces of the organic anti-reflection film 14 and the photoresist 15. Then, as shown in FIG. 4D, the reaction product 16 also functions as a mask when the polycrystalline Si film 13 is etched.

Further, in order to transfer the Si wafer 11 to an ECR type etching apparatus for etching the polycrystalline Si film 13, the Si wafer 11 is removed from the ECR type etching apparatus in which the organic antireflection film 14 is etched. When taken out, the chlorine in the reaction product 16 reacts with the moisture in the atmosphere as shown in FIG. 4C, and the volume of the reaction product 16 expands.

For this reason, as shown in FIG. 4D, the width of the polycrystalline Si film 13 is significantly larger than the width of the photoresist 15, and a short circuit between wirings may occur.
Moreover, as shown in FIG. 5 which is a plan view in the state of FIG. 4D, the volume of the reaction product 16 does not expand uniformly,
The width of the polycrystalline Si film 13 also becomes non-uniform. For this reason, FIG.
In the conventional example shown in (1), it was difficult to manufacture a semiconductor device having excellent reliability and characteristics.

Therefore, according to the invention of the present application, a pattern close to the pattern formed on the organic film can be transferred to the base,
It is an object of the present invention to provide a pattern forming method capable of forming a desired pattern on a base of an organic film and manufacturing a semiconductor device having excellent reliability and characteristics.

[0014]

According to a first aspect of the present invention, there is provided a pattern forming method, wherein a pattern is formed on an organic film by etching using a gas containing a halogen element, and then the pattern is transferred to a base of the organic film. The method for forming a pattern is characterized in that before exposing the pattern to an atmosphere containing moisture, the pattern and the underlayer are covered with a coating film having a moisture permeation inhibiting ability.

According to a second aspect of the present invention, in the method for forming a pattern according to the first aspect, an organic coating film is used as the coating film.

According to a third aspect of the present invention, in the pattern forming method of the second aspect, the organic coating film is formed using a hydrocarbon gas as a raw material.

According to a fourth aspect of the present invention, in the pattern forming method of the third aspect, a CH ₄ gas is used as the hydrocarbon gas.

According to a fifth aspect of the present invention, in the pattern forming method of the second aspect, the organic coating film is formed using a fluorocarbon gas as a raw material.

According to a sixth aspect of the present invention, in the pattern forming method of the fifth aspect, any one of CHF ₃ gas, CH ₂ F ₂ gas, and CH ₃ F gas is used as the fluorocarbon gas. Features.

As described above, in the pattern forming method according to any one of the first to sixth aspects, since the pattern and the base are covered with the coating film having a moisture permeation inhibiting ability, the reaction product of the halogen element and the base material is formed. Even if is attached to the pattern, moisture does not enter the reaction product from the outside. Therefore, even if the pattern is exposed to an atmosphere containing moisture before the pattern is transferred to the underlayer of the organic film, the reaction product attached to the pattern does not expand in volume due to the reaction between the halogen element and moisture.

According to a seventh aspect of the present invention, in the method for forming a pattern according to the first aspect, the halogen element is reacted with hydrogen while heating instead of the coating with the coating film. Features.

The method for forming a pattern according to claim 8, in the pattern forming method according to claim 7, H ₂ gas,
The reaction is performed using either alcohol gas or ammonia gas.

According to a ninth aspect of the present invention, in the pattern forming method of the eighth aspect, either the rare gas or the N ₂ gas is used as a diluent gas.

As described above, in the pattern forming method according to claims 7 to 9, since the halogen element is reacted with hydrogen while heating, the reaction product of the halogen element and the base material adheres to the pattern. However, the compound of the halogen element and hydrogen is effectively eliminated, and the halogen element is removed from the reaction product. Therefore, even if the pattern is exposed to an atmosphere containing moisture before the pattern is transferred to the underlayer of the organic film, the reaction product attached to the pattern does not expand in volume due to the reaction between the halogen element and moisture.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, first and second embodiments of the present invention applied to patterning of an organic antireflection film and a polycrystalline Si film will be described with reference to FIGS.
FIG. 1 shows a first embodiment. Before describing the first embodiment, a high-frequency bias application type plasma etching apparatus used in the first and second embodiments will be described.

As shown in FIG. 2, in this apparatus, an ECR type etching chamber 21 and a microwave downflow type surface processing chamber 22 are connected by a gate valve 23. Microwaves generated by the magnetron 24 in the etching chamber 21 pass through the waveguide 25 and enter the quartz bell jar 26, and the interaction between the magnetic field formed by the electromagnet 27 and the microwaves generates an ECR discharge. , Quartz bell jar 26
Plasma is generated in the inside.

The Si wafer 11 is fixed on a stage 28 by an electrostatic chuck 31 or a clamp, and a bias voltage of 800 kHz is applied to the Si wafer 11 by a bias generator 32, so that the ion species in the plasma is reduced to Si.
The light enters the surface of the wafer 11 and is etched.

Also in the surface treatment chamber 22, the microwave generated by the magnetron 33 enters the quartz bell jar 35 through the waveguide 34 and is surrounded by the quartz bell jar 35 and the punching metal 36 made of aluminum. Microwave discharge occurs in the range of The radical species in the plasma generated by the microwave discharge reach the surface of the Si wafer 11 on the stage 37, and the surface treatment is performed.

As shown in FIGS. 1A and 1B, also in the first embodiment, the organic antireflection film 14 is formed in the etching chamber 21 of the apparatus shown in FIG. Until the etching is performed, substantially the same steps as those in the conventional example are performed. Therefore, also in the first embodiment, the underlying polycrystalline Si film 13 is formed while the organic antireflection film 14 is being over-etched.
Is sputtered, and a reaction product 16 adheres to the side surfaces of the organic antireflection film 14 and the photoresist 15.

However, in the first embodiment,
The Si wafer 11 is transferred to a stage 37 in the surface treatment chamber 22 by a transfer system (not shown) via the gate valve 23, and discharge under the following conditions is performed in the surface treatment chamber 22.

Gas: CHF ₃ = 40 SCCM Pressure: 90 Pa Microwave output: 1000 W Wafer temperature: 25 ° C. Processing time: 15 seconds

As a result, as shown in FIG.
A fluorocarbon polymer film 38 of about 0 nm is formed on the entire surface. Thereafter, as shown in FIG. 1D, the polycrystalline Si film 1 is etched using an ECR type etching apparatus under the same conditions as in the above-described conventional example, using the photoresist 15 as a mask.
3 is etched.

In the first embodiment as described above, since the etching chamber 21 and the surface treatment chamber 22 of the apparatus shown in FIG. 2 are connected by the gate valve 23, the organic antireflection film 14 is formed in the etching chamber 21. After etching, the Si wafer 11 is not exposed to the atmosphere until the fluorocarbon polymer film 38 is formed in the surface treatment chamber 22.

Further, in order to transfer the Si wafer 11 to an ECR type etching apparatus for etching the polycrystalline Si film 13, the Si wafer 11 is transferred from the apparatus shown in FIG.
Even if is taken out into the atmosphere, the permeation of moisture is prevented by the fluorocarbon polymer film 38, so that moisture in the atmosphere does not enter the reaction product 16.

Therefore, as shown in FIG. 1 (c), chlorine in the reaction product 16 does not react with moisture in the atmosphere.
The volume of the reaction product 16 does not expand. Therefore, FIG.
As shown in (d), a pattern close to the pattern formed on the photoresist 15 can be transferred to the polycrystalline Si film 13.

In the first embodiment, the CHF ₃ gas is used to form the fluorocarbon polymer film 38. However, instead of the CHF ₃ gas, other gases such as CH ₂ F ₂ gas and CH ₃ F gas are used. May be used. Further, a hydrocarbon polymer film may be formed instead of the fluorocarbon polymer film 38 using a hydrocarbon gas such as a CH ₄ gas.

Further, a carbon polymer film may be formed using a gas containing two or more carbons, and another organic coating film may be formed instead of the carbon polymer film. Furthermore, an inorganic coating film may be formed instead of an organic coating film as long as the transmission of moisture can be prevented.

FIG. 3 shows a second embodiment. Also in the second embodiment, as shown in FIG. 1B, the organic anti-reflection film 14 is etched and the reaction products 16 adhere to the side surfaces of the organic anti-reflection film 14 and the photoresist 15. Then, substantially the same steps as those of the first embodiment shown in FIG. 1 are executed, except that a discharge under the following conditions is performed in the surface treatment chamber 22.

Gas: H ₂ / Ar = 5/100 SCCM Pressure: 90 Pa Microwave output: 1000 W Wafer temperature: 80 ° C. Processing time: 15 seconds

The hydrogen radicals generated by the above discharge and chlorine remaining on the surface of the Si wafer 11 including the surface of the reaction product 16 react as described below to form hydrogen chloride. H + Cl → HCl ↑

Since hydrogen chloride has a low boiling point and a high vapor pressure, hydrogen chloride is easily desorbed from the surface of the Si wafer 11. Moreover, since the Si wafer 11 is heated to a temperature higher than room temperature, as is apparent from the above conditions, hydrogen chloride is effectively desorbed from the surface of the Si wafer 11 and chlorine is removed from the surface of the Si wafer 11. Almost removed.

Therefore, in the second embodiment, in order to transfer the Si wafer 11 to an ECR type etching apparatus for etching the polycrystalline Si film 13, the Si wafer 11 is removed from the apparatus shown in FIG. 3A, there is no expansion of the volume of the reaction product 16 due to the reaction between chlorine in the reaction product 16 and moisture in the atmosphere, as shown in FIG. Accordingly, a pattern close to the pattern formed on the photoresist 15 can be transferred to the polycrystalline Si film 13 as shown in FIG.

In the second embodiment, H ₂ and A
The reaction with chlorine was carried out using a mixed gas with
A gas containing hydrogen, such as an alcohol gas such as H ₃ OH gas or C ₂ H ₅ OH gas or an ammonia gas, may be used instead of the H ₂ gas. In addition, a rare gas such as He gas or Ne gas, N ₂ gas, or the like may be used as a diluent gas instead of Ar gas, and the diluent gas may not be necessarily used.

Further, the Si wafer 11 was heated to 80 ° C. when the reaction between hydrogen and chlorine was performed. However, in order to prevent the composition of the photoresist 15 from being altered, the photoresist 15 was heated.
It is effective to heat to a temperature as high as possible below the glass transition temperature of the resin in it, and preferably to a temperature in the range of 60 to 120 ° C.

In the first and second embodiments, the organic antireflection film 14 is patterned using a gas containing chlorine. However, the organic antireflection film 14 is formed using a gas containing a halogen element other than chlorine. The present invention can be applied to the case where the film 14 is etched.
The invention of the present application can also be applied to the case where an organic film other than 4 is etched.

In the first and second embodiments described above, the polycrystalline Si film 13 is patterned using the photoresist 15 as a mask, but the WSi ₂ film, CoSi ₂ film,
a silicide film such as an iSi ₂ film, a polycide film in which a silicide film is laminated on a polycrystalline Si film,
The invention of the present application can also be applied to patterning of _two films, Si ₃ N ₄ films, W films, Al films, Ti films, TiN films, and the like.

Further, the apparatus shown in FIG. 2 used in the above first and second embodiments has an ECR type etching chamber 21 and a microwave downflow type surface treatment chamber 22.
The parallel plate RIE chamber, the inductively coupled plasma etching chamber, or the like may be used as the etching chamber 21, and the parallel plate RIE room, the plasma etching chamber, the inductively coupled plasma etching chamber, or the like may be used as the surface treatment chamber 22. Also, etching chamber 2
1 and the surface treatment chamber 22 may be the same chamber.

[0048]

According to the pattern forming method of the present invention, even if the pattern is exposed to an atmosphere containing moisture before the pattern is transferred to the underlayer of the organic film, the reaction product adhering to the pattern has a halogen. There is no volume expansion due to the reaction between elements and moisture. Therefore, a pattern close to the pattern formed on the organic film can be transferred to the base, a desired pattern can be formed on the base of the organic film, and a semiconductor device having excellent reliability and characteristics can be manufactured. it can.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a first embodiment of the present invention in the order of steps.

FIG. 2 is a schematic side view of an apparatus used in the first and second embodiments of the present invention.

FIG. 3 is a side sectional view sequentially showing the second half of the steps of the second embodiment of the present invention.

FIG. 4 is a side sectional view showing a conventional example of the invention of the present application in the order of steps.

FIG. 5 is a plan view of the state shown in FIG.

[Explanation of symbols]

13 Polycrystalline Si film (underlying) 14 Organic antireflection film (organic film) 38 Fluorocarbon polymer film (coating film)

Claims (9)

[Claims] 1. A method for forming a pattern on an organic film by etching using a gas containing a halogen element, and then transferring the pattern to a base of the organic film, exposing the pattern to an atmosphere containing moisture. A method for forming a pattern, characterized in that the pattern and the base are covered with a coating film having a moisture permeation inhibiting ability. 2. The pattern forming method according to claim 1, wherein an organic coating film is used as said coating film. 3. The pattern forming method according to claim 2, wherein said organic coating film is formed by using a hydrocarbon gas as a raw material. 4. A gas comprising CH ₄ as the hydrocarbon gas.
4. The pattern forming method according to claim 3, wherein a gas is used. 5. The pattern forming method according to claim 2, wherein the organic coating film is formed using a fluorocarbon gas as a raw material. 6. The fluorocarbon gas as CHF
6. The pattern forming method according to claim 5, wherein any one of _three gases, CH ₂ F ₂ gas or CH ₃ F gas is used. 7. Instead of said coating with said coating film,
2. The pattern forming method according to claim 1, wherein the halogen element is reacted with hydrogen while heating. 8. The pattern forming method according to claim 7, wherein the reaction is performed using any one of H ₂ gas, alcohol gas and ammonia gas. 9. The pattern forming method according to claim 8, wherein one of a rare gas and an N ₂ gas is used as a diluent gas.