DD272141A1 - METHOD FOR PRODUCING SILICYL-CONTAINING NEGATIVE RESISTANT IMAGES - Google Patents

Abstract

The invention relates to a method for the production of silicon-containing negative resist images, which are applicable for the production of microstructures in semiconductor materials in the production of highly integrated monolithic circuits for microelectronics. The aim is to provide a process which results in silicon-containing negative resist images by means of an easily prepared solvent-developable negative resist which is suitable both for monolayer and multilayer masking and which has a high dissolving power in the sub-micron range. This is achieved according to the invention by using, as a negative resist, a solution with a total mass fraction of 3 to 25% of a mixture of methylvinylcyclosiloxanes of the general formula with n4 to 6 and halogen-substituted polyacrylates having a molecular weight range Mw105 to 106 and Mn2104 to 2105 in a mass ratio of 5:95 to 50:50 applied homogeneously to a substrate in a homogenous layer for electron beam resists, image-wise irradiated, annealed for at least 5 minutes at 70 to 190 ° C., and the latent negative resist image developed in a ketonic solvent. formula

Description

Title of the invention

Process for the preparation of ailicium Negativreaiatbildern

Field of application of the invention

The invention relates to a method for the production of silicon-containing negative resist images, which is applicable for the production of microstructures in semiconductor materials in the production of highly integrated monolithic circuits for microelectronics.

Characteristic of the known state of the art

The production of negative resist images is generally carried out in a negative resists in one or more layers on a substrate, evaporated in the resist solvent and evaporated by imagewise irradiation with high energy radiation, a latent Reaistbild is generated, which then with the help of developers - in the Usually mixtures of organic solvents - is developed.

The known solvent-developable negative resists consist in the bars of a radiation-chemically reactive polymer and solvents. Due to the action of high-energy radiation occurs in the irradiated areas of the resist layer, a partial crosslinking, so that in the subsequent treatment with a developer, the unirradiated areas are herauagelörjt faster than the irradiated and thus produces a negative image.

The increasing miniaturization of integrated circuits causes the lateral dimensions of the structures to be produced to shrink while the resist layer thickness remains relatively unchanged and the substrate topography increases.

As a result, the limits of dissolution capability of monolayerayatemes have been reached. Thus, the introduction of multi-layer ayatemases further increases the resolution capacity (B. 3. Lin, Solid State Technol, (1983) 5, pp. 105-112). As a technology advantageous Zweachichtreaiatayateme angeeaehen ereaehen whose upper radiation-sensitive layer boundea silicon (M. Hatzakia et al., Proc. Microelectronica Engineering (Lauaanne), p 386, 1981).

Biaher did not convince ea to produce Reaiate with the necessary properties and a reasonable amount of synthetic effort.

U.S. Pat. No. 4,564,576 produces negative reactions on triallylailanes and allylatyrenes. A disadvantage of this type of reactants is their synthesis, since it is necessary to avoid crosslinking in the case of the free-radically initiated polymerization of the polyfunctional unsaturated monomers and, moreover, product workup requires a relatively complicated fractionation in order to obtain an extremely narrow molecular weight distribution.

Polymethylailoxanes generally have glass transition temperatures below room temperature, and vinyl substitutions as low as 0.1 %, as noted in OP 60-143,334, change the glass transition temperature insignificantly. Such soft polymers give z. B, after the development as a result of the swelling rounded structures, the image fidelity considerably reduced.

Those described in OP-PS 60 - 254 035. Negative resists are ladder-shaped polysiloxanes in chemical structure. Their electron beam sensitivities are associated with a 20 kV accelerated-energy path

-5 2 1 · 10 C / cm indicated, is qualitatively insensitive 1st.

In US Pat. No. 4,507,384, predominantly modified phenyl-substituted polyailoxanes are incorporated. The modification is usually chloromethylation and

excludes the use of carcinogenic chlorodimethyl ether

4, Bai acceptable molecular weights, M 10-10,

~ 6 ι 2

only sensitivities of 10 ~ - 10 "° C / cm (acceleration voltage: 20 kV) are obtained.

Object of the invention

It is the object of the invention to provide a process for the preparation of 3 silicon-containing negative resist images by means of a solvent-developable silicon-containing negative resist, its preparation uncomplicated, which is suitable both for Einschlicht- and for multi-layer masking and <3in high resolution in the submicron ,

Explanation of the essence of the invention

The object of the invention is to develop a solvent-developable silicon-containing negative resist that meets the requirements.

The object is achieved in that the negative resist is a solution with a total mass fraction of 3 to 25 % of a mixture of methylvinylcyclosiloxanes of the general formula

j 3

Si - O-

CH = CH

with η = 4 to 6 and halogen-substituted polyacrylates or methacrylates having a molecular weight range M _w = 10 ^b to 10 and R = 2 x 10 to 2 x 10 in a mass ratio of 5:95 to 50: 50 in a solvent commonly used for electron beam resists, preferably chlorobenzene, applied in a homogeneous layer on a substrate, the generated resist layer by means of high-energy radiation

irradiated imagewise and then annealed for at least 5 minutes at a temperature of 70 to 190 ⁰ C, preferably below the glass transition temperature, and then the irradiated latent negative resist image is developed in a ketonic solvent.

The solvent-developable lithium-ligand-negative-type resist used according to the invention contains up to 16.3% by mass of silicon, has a very good film-forming ability and is very sensitive to radiation chemistry. Surprisingly, she has. ¹ that the components of the negative developer used according to the invention are miscible with one another and are compatible in this mass ratio range without phase separation. Due to this, the silicon-containing negative resist of the present invention can be easily adjusted to the respective lithographic requirements by varying the mass ratio of methylvinylcyclosiloxane and polyacrylate in the specified range.

Furthermore, it has been found that annealing after irradiation advantageously improves the quality of the negative resist image, since it reduces solvent-induced swelling. It is preferably tempered below the glass transition temperature of the negative resist.

The methylvinylcyclosiloxanes used according to the invention as starting materials can be used both individually and in For.) Of mixtures. Particularly advantageous is the use of tetramethyltetravinylcyclotetrasiloxane.

Suitable "" halogen-substituted polyacrylates or methacrylates are the homo- and copolymers of polymerized units of the 1-chloro, 2-chloro, 2,2,2-trichloro or 1,2,2,2-tetrachloroethyl acrylate or Furthermore, copolymers of 1-chloro, 2-chloro, 2,2,2-trichloro or 1,2,2,2-tetrachloroethyl methacrylate and up to 75% by mass of the monomers methyl methacrylate, ethyl acrylate, methyl are also suitable - * (- chloroacrylate, methyl - ^ - bromoacrylate or vinylidene chloride.

The crude solution-developable ailicium-containing negative reaction which is suitable for processing is processed into rosiate structures using the known technologies. For example, homogeneous spinel layers are produced directly by spin coating on Srl / SiO 2 subatrates or, in the case of minute masking, on other suitable sublayers. Ea includes the irradiation z. B. with electron, X-ray, ion or Tiof UV rays according to a predetermined pattern. The in-injected negative resist image is developed subsequent to a titration in the range 70-190 ⁰ C, preferably below the glass transition temperature, by treatment with a ketonic Löaungamittel. Suitable developers are acetone, methyl ethyl ketone and mixtures thereof with isopropyl alcohol in conventional proportions.

The solvent-extractable silicon resistive negative resist according to the invention achieves a high resolution in the submicrometer range and is distinguished by an excellent image fidelity of the irradiated structure structure.

embodiments

example 1

8 g of polytetrachloroethyl methacrylate and 2 g of tetramethyltetravinylcyclotetrasiloxane are dissolved together in 32 g of chlorobenzene.

The resulting silicon-containing negative resist is spin-coated on GiO 2 / Si substrates at 3000 rpm in layer thicknesses of 1.7 μm. After removal of adhering solvent residues within 30 min at 70 C, the Resiatschicht is irradiated with electrons under an accelerating voltage of 20 kV and a Doaia of 8 · IG "'C / cm and then annealed for 30 min at 120 ⁰ C. Die Entwicklung des The resist layer is irradiated with a mixture of 1 part of methyl ethyl ketone and 0.75 part of isopropanol.

Example 2

Analogously to Example 1, a resist layer is prepared with electrons of the dose 5 x 10 "C / cm irradiated, annealed and Entwicke.lt i Dia resist layer thickness of the negative resist image produced is 1.62 to»

Example 3

5 6.5 g of polytetrachloroethyl methacrylate (M = 9x10,

- 5

M a 1 x 10) and 3.5 g of tetramethyltetravinylcyclotetrasiloxane

dissolved in 120 g of chlorobenzene. When the film is applied, the solution gives> -n (3000 rpm) 1.5, to thick layers of the coating resist PZ 3.350 (30 min at 250 ⁰ C tempered) layer thicknesses "of 0.43, after a tempering of 30 min at 50 C (weight ratio Polytetrachlorethylmethacrylat to tetramethyltetravinylcyclotetrasiloxane is 65: 35) is irradiated with electron dose 3.2 x 10 C / cm, then heated for 30 min at 120 ⁰ C the Negativresi3tbild obtained after processing according to example 1 is mixed with oxygen. under the

2 conditions of reactive ion etching (13.56 Hz, 0.14 W / cm,

3 oxygen pressure: 10 Pa, oxygen flow rate 5 cm / min) etched into the underlying AZ lacquer layer. After an etching time of 11 minutes, the thickness of the total layer of irradiated areas was 1.78. "

Example 4

Analogously to Example 3, a resist layer is prepared and

-7 2 irradiated with electrons of the dose 8 · 10 C / cm. After monitoring, development and transfer of the negative resist image as in Example 3, the thickness of the total layer of the irradiated areas is 1.8,

Example 5

Analogously to Example 3, a resist film is prepared and coated with helium ions under an acceleration voltage of 40 kV and a dose of 2. 10 ions / cm irradiated. After annealing, developing and transferring the negative resist image as in Example 3, a total layer thickness of 1.76 μm is obtained.

Claims (5)

claims Process for the preparation of negative-resisting silicon-containing images by means of a solvent-developable silicon-containing negative film, characterized in that a reaction with a total of 3 to 25 % of a mixture of methylvinylcyclosiloxanes of the general formula Si - ΟΙ
CH = CH, with η = 4 to 6 and halogen-substituted polyacrylates or methacrylates having a molecular weight range M = 10 to 10 ⁶ and M 2 x 10 ⁴ to 2 x 10 ⁵ and M = 2 · Im * 'to 2 x 10 "" in a mass ratio of 5:95 to 50:50 in a conventional electron beam solvent, preferably chlorobenzene, applied in a homogeneous layer on a substrate, the resulting resist layer by means of Energiereic! "> He radiation irradiated imagewise and then annealed for at least 5 minutes at a temperature of 70 to 190 ⁰ C, preferably below the glass transition temperature, and then the irradiated latent negative resist image is developed in a ketonic solvent. 2. The method according to claim 1, characterized in that al9 Methylvinylcyclo9iloxan preferably Tetramethyltetravinylcyclotetragiloxan is einge9etzt. 3. Process according to claims 1 and 2, characterized in that as halogen-substituted polyacrylates or methacrylates homopolymers of polymerized units of 1-chloro, 2-chloro, 2,2,2-trichloro or 1,2,2, 2-Tetrachlorethylacrylates or methacrylates are used. 4. Process according to claims 1 big 3, characterized in that are used as halogen9subituierte polymethacrylates preferably homopolymers of polymerizing units of 1,2,2,2-Tetrachlorethylmethacrylates, 5. Process according to claims 1 and 2, characterized in that as halogen-substituted polyacrylates or -methacrylate copolymers of 25 to 100% by mass of i-chloro, 2-chloro, 2, 2, ..- trichloro or 1, 2,2,2-Tetrachlorethylmethacrylat and up to 75 mass% of the monomers Methylmethacry.lat, ethyl acrylate, methyl - ^ - chloroacrylate, methyl-FC-bromacrylat or vinylidene chloride used we rd e η.