DD247301A1 - POSITIVE PHOTO COPY LACQUER WITH IMPROVED SURFACE PROPERTIES - Google Patents

Abstract

The invention relates to positive photocopiers having improved surface properties based on novalaks and 1-oxo-2-diazoarene derivatives. The aim of the invention is a reduction of the surface roughness without deterioration of the photolithographic properties. This is achieved by adding at least one fluoroorganic compound of the general formula C 6 F 6 (O (CH 2) n (CF 2) m R) a to the paints in amounts of 0.001 to 1.0% by weight, where C 6 F 6a is an a-substituted, perfluorinated Benzene nucleus, pure hydrogen or fluorine atom, denote the numbers 1 or 2 and an integer from 2 to 10.

Description

Subject of the invention

The invention relates to positive photocopiers having improved surface properties on the basis of novolaks and i-oxo-2-diazoaren derivatives, which are suitable for the production of microelectronic components.

Characteristic of the known technical solutions

Derivatives of 1-oxo-2-diazoarensulfonic acids have been known for some time as photosensitive components of photocopying varnishes (cf., inter alia: Light-Sensitive Systems / Kosar, J.-New York 1965 - pp. 343-351, DE-PS 854890, 865,108, U.S. Patent 3,046,121). When exposed to nitrogen, they are converted into 5-membered ketenes, which, in contrast to the starting materials, are readily soluble in aqueous alkalis. It is also known, such photocopying to improve the hardness and thickness and the development properties and behavior in the printing process resins, especially novolacs, add (DE-PS 11 95166 u.a.). Positive photocopying varnishes of this composition are used especially in polygraphy and electrical engineering, but also in microelectronics. At derz.Z. However, the prevailing coating method by Schleuderbeguß occur in the paint layers certain errors that are addressed in slow rotation as cloudiness, with rapid rotation as a radial strip. They are associated with the increase in the surface tension at the boundary layer to the air, which is caused on the one hand by cooling the surface due to the evaporation of the solvent, on the other hand by increasing the concentration at the surface. As a result of this or by subsequent processes of this process, a non-uniformity of the layer is effected, which is usually referred to as surface roughness and is generally in the range of 3 to 4% of the layer thickness, but can also reach values of more than 10% of the layer thickness. This surface roughness leads in particular in the imaging of documents with small details by projection lithography to significant aberrations, because the exposure reflections occur that lead to the exposure especially at the limits of exposure errors.

In order to reduce or eliminate the surface roughness, numerous measures have been described in the patent literature, which consist predominantly in that certain surface-active auxiliaries are added to the photoresist solution. Thus, DE-OS 3022473 describes the addition of a surface-active polysiloxane which consists of dialkylsiloxane and hydroxylalkyl units. Although the surface roughness is considerably reduced by this addition, on the other hand (as with the addition of other silicon-containing surfactants, cf., inter alia, DD-PS 225801), the adhesion is considerably worsened. In DE-OS 3022362 a nonionic ester of a perfluoroalkanoic acid with a polyethylene glycol or an ether of a highly fluorinated or perfluorinated alkanol is claimed with a polyethylene glycol for the same purpose, while in DE-OS 3215112 a fluorinated organic compound of the general formula R _r AY is described where Rf is a partially or completely fluorinated radical and Y is a hydrophilic radical. These "fluorosurfactants" also reduce the surface roughness, but when used in practice, they also have significant drawbacks When using lacquer solutions that have been stored for a long time, leakage of the surfactant is often observed, making the surfaces rough In addition, the above-mentioned fluorosurfactants are predominantly relatively difficult to access, so that their use is associated with increased costs Finally, even with fluorosurfactants a certain reduction in the adhesive strength of the coating layers can occur.

Object of the invention

The aim of the invention is therefore to improve the application properties of positive photocopying varnishes containing at least one derivative of a 1-oxo-2-diazoarene-sulfonic acid and preferably novolaks and optionally further auxiliaries, in particular a reduction of their surface roughness while avoiding the disadvantages listed above.

Explanation of the essence of the invention

The invention has for its object to find suitable additives for positive photocopying, which cause a strong reduction in the surface roughness, are inexpensive and cause at least no deterioration in the shelf life and adhesion of the paints produced therewith. This object is achieved in that the Fotokopierlacken one or more fluoroorganic compounds of the general formula

_C6 F6-a- [O- (CH _{2) n} - (CF _{2) m} -R] _a

contain, where

СбРб-а- an a-substituted, perfluorinated benzene nucleus,

R is a hydrogen or fluorine atom,

a total number of 1 to 3

η is the number 1 or 2 and

a total of 2 to 10

mean.

The above-mentioned compounds are soluble in the common organic solvents and exhibit surface-active properties therein. This is surprising insofar as the molecular structure of the compounds according to the invention does not suggest a surface-active behavior. However, they should be referred to as surfactants below.

The substances according to the invention are obtained in the nucleophilic reaction of the fluoroaromatics with fluorine-containing alcoholates and are formed as a function of the molar amount of the alcohol component. They are isolated from the reaction mixture by distillation and added to the lacquer solutions in amounts of from 0.001 to 1.0% by weight, based on the total solids content of the photocopying lacquer. Table 1 below summarizes some of the compounds of this invention.

Table 1

Connection no.

R-

10 8 4 6

F-H-H-F-

embodiments

There have been 5 solutions each

26 g of a semialternating o-cresol-p-cresol-bis (p-cresol) novolak resin (see DD-PS 211415, n ° 6), 7g 3,4,5-tris (1'-oxo) 2'-diazonaphthenesulfonyloxy-5 '-) benzophenone and 67 g of a solvent mixture of 85% by weight of ethyl glycol acetate, 10% by weight of xylene (mixture of o-, m- and p-xylene) and

5Gew .-% butyl acetate produced.

One of these solutions was used as a comparative sample, while the others were mixed with 0.1 wt .-% per one of the compounds 1 to 4. The samples were filtered on Ο, δμ, Γη and spin-coated at 4000 rpm onto Si wafers provided with a 0.8 μm thick oxide layer. The layer thickness was in all cases 1.5μΓη ± 5%. While the comparative sample showed clear radial stripes, no such phenomena were seen on Samples 1 to 4.

The layers were annealed for 30 min at 80 ⁰ C and the surface roughness determined using a Tastschnitt meter. The test results are summarized in Table 2 below.

Table 2

Sample No.

Fluorverb. No.

Gehaltd. surfaces Gesamtlsg. (Wt .-%) roughness (nm) 35 0.1 10 0.1 8th 0.1 8th 0.1 6

comparison

1 2 3

To test the lithographic properties, wafers coated with the sample solutions were exposed imagewise to the total radiation of a high-pressure mercury lamp HBO 200 (VEB Optische Werke Rathenow) with an output of 180 mJ / cm ² , developed with aqueous NaOH (pH 13.3) least. Rinsed water and hardened the relief image at 130 ° C for 20 min. The subsequent etching with potassium hexacyanoferrate (III) solution according to DD-PS 104566 Beisp.1 showed that the samples added with the fluorine compounds according to the invention had no differences in respect of adhesion and etching resistance compared with the comparative sample. Even after storage for 6 months, no change in layer thickness, surface roughness and photolithographic properties was observed for Samples 1 to 4 with the same processing.

Claims (2)

Invention claim: 1. Positive photocopy coatings having improved surface properties, consisting of at least one derivative of an i-oxo-2-diazoarensulfonic, at least one non-water-soluble, but swellable in aqueous alkaline solvents or soluble binder, preferably a novolak, and other auxiliaries, such as solvents, Dyes and / or curing agents, characterized in that they contain at least one fluoroorganic compound of the general formula C ₆ F6_ _a - [O- (CH _{2) n} - (CF _{2) m} -rl _a contain, where C ₆ F6_ _a - an a-substituted, perfluorinated benzene nucleus, R is a hydrogen or fluorine atom, a is an integer from 1 to 3, η is the number 1 or 2 and m is an integer from 2 to 10 mean. 2. Positive photocopy coatings according to item 1, characterized in that they contain the fluoro-organic compound in amounts of 0.001 to 1.0 wt .-%, based on the total solids content of the photocopying varnish.