JPH0469662A - Resist processing method - Google Patents

Abstract

PURPOSE:To develop the resist by a perfect dry process using oxygen plasma and to cleanly strip the resist containing silicon atoms from a substrate by irradiating the resist containing a silyloxy compound and/or a silylamino compound and a radiation sensitive agent for forming an acid by radiation, heating it, and removing the resist by oxygen plasma. CONSTITUTION:The resist film comprising 100pts.wt. of poly-p-trimethylsilyloxy- styrene and 12pts.wt. of p-nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate is formed on the substrate and it is exposed to far ultraviolet rays past a mask for 60sec in an exposing device, and then subjected to a heat treatment on a hot plate at 130 deg.C for 2min, and developed by oxygen plasma in a developing device for 3min to obtain a rectangular resist pattern of 0.65mum width and 1.0mum thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resist processing method, and more specifically to a resist processing method suitable for forming and peeling off fine patterns used in the manufacture of semiconductor integrated circuits, magnetic bubble memory devices, etc. Regarding the processing method of I.

[Prior Art] Conventionally, typical resists used in the manufacture of semiconductor integrated circuits, etc. include negative resists using cyclized rubber and bisazide photosensitizers, and negative resists using novolak resin and quinonediazide photosensitizers. Positive resists are known. In addition to these resists, resists containing chlorinated polymethylstyrene and silyloxy compounds are also known, and various resists have been developed depending on the application.

When using these resists to manufacture semiconductor integrated circuits, etc., a thin film of resist is first formed on a substrate such as a silicon wafer, and then selectively irradiated with light or electron beams, etc., to coat the organic Processed with a developer such as a solvent or aqueous alkaline solution, and in the case of a negative type, the area that was not irradiated with light or electron beams, etc., and in the case of a positive type, the area that was irradiated with light or an electron beam, etc. is dissolved in the developer. Then, a resist pattern is formed on the substrate. The resist pattern thus formed plays an important role in selectively performing steps such as ion implantation and wiring, which are one of the manufacturing steps for semiconductor integrated circuits.

In recent years, with the miniaturization of semiconductor integrated circuits, the manufacturing process has attracted attention, and the development process mentioned above has changed from wet development using a developer to dry development using anisotropic oxygen plasma. A shift to development is being considered. For more information on the technical content and effects of L.Lye development, please see "Introducti."

n to old croHthography” (G, C, W
The technology is roughly divided into a three-layer process and a layer process. In the three-layer process, a three-layer resist I is formed using a material that is not resistant to oxygen plasma for the bottom layer, a material that is resistant to oxygen plasma for the middle layer, and a material that is resistant to etching of the middle layer for the top layer. After buttering exposure, the two layers are wet developed, the intermediate layer is etched using the formed resist pattern as a mask, and anisotropic oxygen plasma is etched using the formed intermediate layer pattern as a mask. Develop the lower layer. In the two-layer process, a two-layer resist is formed using a material that is not resistant to oxygen plasma for the bottom layer and a material that is resistant to oxygen plasma for the second layer, and after the patterning exposure, the upper layer is wetted and developed. Next, the lower layer is developed with anisotropic oxygen plasma using the formed resist pattern as a mask.

However, in such a conventional dry development process,
It is necessary to carry out uniform development once between the buttering exposure and the dry development, which has the disadvantage that it is not completely dry.

On the other hand, in the manufacture of semiconductor integrated circuits, etc., the resist pattern formation process described above is repeated many times, so after completing step (1), it is necessary to remove the resist pattern used in order to proceed to the next step. Furthermore, if the resist pattern formed during pattern formation deviates from a certain standard, it is necessary to peel and remove the resist film and form the pattern again. Conventionally, for stripping off these resist i-patterns, a method has been adopted in which a special stripping solution corresponding to each resist is used to dissolve and remove the resist pattern. However, this method has the problem that the substrate may be contaminated after peeling, and that waste liquid treatment for environmental protection is costly. As a method for solving this problem, a technique is known in which the resist pattern is burned and vaporized in oxygen plasma. With this method, the substrate is not contaminated after peeling, but
In order to apply this method, the composition of the resist must consist only of elements that can be vaporized by combining with oxygen, and in the case of resists containing silicon atoms, it is possible to There was a problem in that silicon oxide was formed and remained on the substrate as ash without being vaporized.

An object of the present invention is to solve the above-mentioned problems of the prior art, to completely dry the development of the resist after patterning exposure using oxygen plasma, and to clean the resist containing silicon atoms from the substrate. An object of the present invention is to provide a method for processing a resist that can be peeled off.

[Means for Solving the Problems] The present invention involves irradiating a resist containing a silyloxy compound and/or a silylamino compound and an acid-forming radiation-sensitive agent with radiation, then heating it, and then using oxygen plasma to remove the radiation. The present invention relates to a method of processing a resist l-, which is characterized by removing a portion of the resist.

The silyloxy compound used in the present invention has, for example, the general formula (1) R'R2R' 5iO (wherein R1, R
z and R3 have a silyloxy group represented by a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group or a hensyl group], and have a silyloxy group represented by the general formula (II) (R' R2R3S iO')-VR' (
n) (wherein R1, R2 and R3 are the same as above, R4 is an m-valent aliphatic or aromatic hydrocarbon group which may have a substituent, m and n are positive integers, , usually 1 to 1.0OO1 preferably 1 to 500 (however, m
Indicates an integer of ≧n).

Such compounds are disclosed in JP-A-60-37549, JP-A-60-52845, and JP-A-63-29212.
For example, the following general formula (I
The compound represented by II) or (IV) has the following general formula (
Examples include polymers or copolymers having at least one repeating unit represented by V), (Vl), (■), or (■).

l2 CI□ (Vl) CH□-C-(■) 0 (CHz) rO3iR'R2R' (wherein, R1-R3 and R5 to RI6 are hydrogen atoms, alkyl groups having 1 to 4 carbon atoms, phenyl groups, or benzyl group, R1 to RI3 are hydrogen atoms or methyl groups, "is 1 to 4
).

RI, , Rff and R5 to RI0 in the above general formula
is preferably a methyl group or an ethyl group, which are easily dissociated and volatilized by acid.

Specific examples of this silyloxy compound include compounds having the following repeating units.

H3 H3 The silylamino used in the present invention has the general formula (i) (R'R2R''Si), Xz-N (wherein, R l = R2 and R3 are the same as above, and group, S represents 1 or 2), and has a silylamino group represented by the general formula (ii) [(R' R2 R' S +)Xz-s N
-+TR'F) (wherein, R', R", R', R
', X, S and n are the same as above).

Such compounds are disclosed in JP-A-60-37549, JP-A-60-52845, and JP-A-63-2921.
For example, the following general formula (
Examples include compounds represented by iii) or (iv), and polymers or copolymers having at least one type of repeating unit represented by the following general formulas (v) to (ix).

RI4 I2 and -O = (Cllz)rN(SiR'R2R3)z (in the formula,
R1-R3, R5 to R'1 and r are the same as above, and R14 and RI5 represent a hydrogen atom or a methyl group).

The silyloxy compound or the silylamino compound may be used alone or in combination.

Specific examples of silylamino compounds include compounds having the following repeating units.

Silyloxy compounds containing the double general formulas (V) to (■) or silylamino compounds containing the general formulas (v) to (IX) may contain other repeating units, such as styrene, α- Methyl styrene, methyl (meth)acrylate, ethyl (meth)
It may contain styrene monomers such as acrylate, vinylpyridine, and N-vinylpyrrolidone, (meth)acrylate monomers, nitrogen-containing vinyl monomers, and the like.

The acid-generating radiation-sensitive agent used in the present invention is
No. 115932, Japanese Patent Application Laid-open No. 60-37549,
JP-A-60-52845, JP-A-63-2921
28, JP-A-1-293339, etc., and examples thereof include onium salts, (poly)halogen compounds, p-quinonediazide compounds, nitrobenzyl esters, and sulfonic acid esters.

Specific examples of these compounds include onium salts such as trinohenylsulfonium triflate, 1-t-
Butylphenyldiphenylsulfonium hexafluorophosphate, bis(4,4"-t-butylphenyl)iodonium hexafluoroantimonate, bis(4,4"-t-butylphenyl)iodonium hexafluoroantimonate,
Examples of '-t-butylphenyl)iodonium tetrofluoroborate, polyhalogens include the following compounds, and CH3 sulfonic acid esters include the following compounds.

In the O-quinonediazide compound, the following compound is used, and in the case of the nitrobenzyl ester, the following compound is OCz H5. The amount of acid-forming radiation sensitizing agent is usually 1 to 20 parts by weight per 100 parts by weight of the compound.

In the present invention, a material having low oxygen plasma resistance, such as a novolak resin and a 1,2-quinonediazide-based compound, is used between the resist containing the silyloxy compound and/or silylamino compound and an acid-forming radiation-sensitive agent and the substrate. It is also possible to form a positive type film consisting of the following.

There are no particular restrictions on the radiation used in the present invention, such as ultraviolet rays, far ultraviolet rays (including excimer laser), X-rays,
Gamma rays, charged particle beams, etc. are used.

Conditions for radiation irradiation are appropriately set depending on the resist used.

The heating conditions in the method of the present invention are also appropriately set depending on the resist used, and are usually 30 to 200°C, preferably 50 to 150°C.

In the present invention, the removal of the resist using oxygen plasma may be performed using a commercially available device such as a plasma developing device (manufactured by Nippon Gosei Rubber Co., Ltd., Plus Master De), a plasma asher (manufactured by Plasma System Co., Ltd., DBS-106254AEN), etc. The removal conditions can be set as appropriate depending on the device and type of resist.

[Effect]

A silyloxy compound or a silylamino compound dissociates its silyloxy group or silylamino group by the action of an acid. Therefore, when a resist containing these compounds and an acid-forming radiation-sensitive agent that forms an acid upon irradiation with radiation is irradiated, the resist will be damaged. An acid is formed to dissociate the silyloxy or silylamino group. Moreover, the dissociation of silyloxy groups or silylamino groups is promoted by heating after radiation irradiation, and their volatilization from the resist is promoted. In this way, the silyloxy groups or silylamino groups in the resist are completely volatilized during the radiation irradiation and heating process, so there are no silicon atoms in the resist, and when this resist is developed using oxygen plasma,
The resist in the irradiated area can be completely vaporized, while
Since silicon atoms are present in the non-irradiated area, it is easily vaporized and remains as a pattern. Furthermore, by irradiating the entire surface of the resist and burning it in oxygen plasma, a substrate in which the resist is separated by ff1lJ can be obtained without being contaminated.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 Silicon substrate 100 parts by weight of poly (p-1-limethylsilyloxystyrene) (number average molecular weight 30,000: polystyrene equivalent molecular weight (the same applies hereinafter)) and p-nitrohensyl-910- A resist film (film thickness: 1 μm) consisting of 12 parts by weight of Jetoxyanthracene-0C2T-1 was formed, and this resist film was exposed to a deep ultraviolet exposure device (gear/7
"JPLA-5 2 1 F) was used to expose the resist film to light for 60 seconds through a mask, followed by heat treatment on a hot plate at 130°C for 2 minutes. After that, this resist film was exposed to light using a plasma developing device. (Plasma Master De, manufactured by Japan Synthetic Rubber Co., Ltd.) was developed in oxygen plasma for 3 minutes, and a rectangular resist pattern with a width of 0.65 μm and a thickness of ], O // m could be obtained. Ta.

Comparative Example 1 Example 1 was prepared using the same resist film as used in Example 1.
After exposure and heating in the same manner as above, a tetramethylammonium hydroxide aqueous solution (2.4% by weight)
When developed for 1 minute, the result was 0.

A trapezoidal resist pattern with a width of 65 μm was obtained.

Example 2 After forming a 1 μm thick quinone diazide positive resist (PFR7750 manufactured by Japan Synthetic Rubber Co., Ltd.) on a silicon substrate, a 0.3 μm thick poly(p-trimethylsilyloxystyrene) (number average molecular weight 30,000) was formed. 100 parts by weight and p
-Nitrohensyl 9,10-jethoxyanthracene-
A resist film consisting of 1.12 parts by weight of 2-sulfone was formed, and this resist film was exposed to light, heated, and developed in oxygen plasma in the same manner as in Example 1.
A rectangular resist pattern with a width of 65 μm and a thickness of 1.3
It was possible to obtain it in μm.

Comparative Example 2 Example 2 was prepared using the same resist film as used in Example 2.
After exposure and heating in the same manner as above, a tetramethylammonium hydroxide aqueous solution (2.4% by weight)
When developed for 1 minute, a resist pattern was obtained in which the underlying positive resist was not developed.

Example 3 The entire surface of the resist pattern formed in Example 1 was exposed and heated in the same manner as in Example 1, and then the resist pattern was heated using a plasma asher (manufactured by Plasma System Co., Ltd.).
DE1106-254AEN) for 10 minutes in oxygen plasma to burn off resists 1 to 1, and the resists were cleanly peeled off from the substrate.

Example 4 Poly(p-trimethylsilyloxystyrene) (number average molecular weight 30,000) 1. 00 parts by weight and an X-ray irradiation device (MX-14, manufactured by Micronics) on the entire surface of a resist pattern formed using a resist made of triphenylsulfonium triflate.
Irradiation was performed for 30 minutes using a 130° C. hot plate, and then heating was performed for 2 minutes on a 130° C. hot plate. Thereafter, this resist pattern was treated in oxygen plasma for 5 minutes using the plasma developing apparatus used in Example I to burn the resist, and the resist was cleanly peeled off from the substrate.

Comparative Example 3 The resist pattern formed in Comparative Example 1 was treated in oxygen plasma for 30 minutes using the plasma asher used in Example 3 to burn the resist, but there were no traces of the pattern on the substrate. As a result, the resist could not be removed cleanly.

〔Effect of the invention〕

According to the resist processing method of the present invention, silicon atoms in the resist can be completely dissociated and volatilized.
Oxygen plasma treatment makes it possible to completely dry the development process of the resist I and to cleanly peel the resist I from the substrate L, making it possible to simplify the manufacturing process of semiconductor integrated circuits and reduce costs. , it can also be used to manufacture magnetic bubble memory devices.

Claims (1)

[Claims] (1) A resist containing a silyloxy compound and/or a silylamino compound and an acid-forming radiation-sensitive agent is irradiated with radiation, then heated, and then the resist in the irradiated portions is removed using oxygen plasma. How to process the resist.