JPH02151863A - Resist material - Google Patents

Abstract

PURPOSE:To easily dissolve the unexposed part of a resist layer by a developing soln. entering the inside of contact holes and to easily obtains resist patterns having overhanging shapes by incorporating materials having absorption in a wavelength region of a g ray. CONSTITUTION:At least wavelength region of the g ray are incorporated into the resist material contg. the naphthoquinone diazide sulfonate of a novolak resin. Since the materials having the absorption in the wavelength region of the g ray are incorporated into the resist material, the polarity change by photoreaction takes place preferentially in the depth from the surface of the resist layer down to a certain depth and this part becomes insoluble in the developing soln. and the solubility with the developing soln. in the part deeper than the above-mentioned part is maintained. The ratio of solubility of both the parts with respect to the developing soln. is this increased. Then, even if the developing soln. is hardly intrudable into the contact holes, the developing soln. entering the contact holes easily dissolves the unexposed part of the resist layer and the resist patterns having the overhanging shapes are easily obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a resist material for forming fine battens used in the manufacture of semiconductor devices, other electronic devices, optical devices, precision mechanical elements, and the like.

(Prior Art) As the demand for higher integration of semiconductor devices increases, a technology capable of finer processing becomes necessary. As a microfabrication technology that can meet such demands, a resist pattern is formed by phosphorography technology using ultraviolet rays, electron beams, X-rays, or deep-UV as a light source, and ion plasma, etc. Techniques for processing substrates and the like by dry etching are known. As is well known, such microfabrication technology is a synthesis of various elemental technologies such as resist materials, exposure technology, and etching technology. For this reason, excellent characteristics are required for each of these elemental technologies, and high resolution, high dry etching resistance, etc. are also required for resist materials.

The applicant of this application also proposed a resist material (LMR
It is called and sold in mass quantities. ) has been proposed for some time. This resist material is a negative type, and by exposing it to electron beams or deep ultraviolet rays and developing it with a developer containing acetate or alkyl ketone, it is possible to form a resist pattern on the submicron order (specially 146047/1986, JP 181535/1983), and by exposing to ultraviolet light with a wavelength of 350 to 450 nm and developing with a chlorinated alkane or a developer containing a chlorinated alkene, a resist pattern of submicron order can be obtained. It is possible to form
297842).

In addition, this resist material can be used to easily obtain a resist pattern with an inverted tapered cross section by controlling the exposure amount and development time. It was extremely effective in forming a dry etching mask required for taper forming techniques such as tapering the edges of contact holes.
46750') (Problems to be Solved by the Invention) However, with a stepper using a resist material containing the above-mentioned novolac resin naphthoquinone diazidozol:phonic acid ester and 9 wires, When an attempt is made to form a resist pattern for a hole, there is a problem in that a desired inverted tapered resist pattern cannot be obtained for the reasons explained below.

■...Naphthoquinonediazide sulfonic acid ester of novolac resin is 5. In order to form a desired reverse tapered resist pattern by insolubilizing only a predetermined portion from the surface in order to obtain a fine contact hole, the absorption of the 9-line is relatively small, so the exposure light is applied only to the thickness of the resist material. It is easy to reach deep in the direction, and the volume of the molecularly dissolved part is easy to increase.

(2) The finer the contact hole becomes, the more difficult it is for the developer to penetrate into the contact hole, making it difficult for the unexposed portions of the walls of the contact hole to be dissolved.

Due to these problems, a resist material containing naphthoquinonediazide sulfonic acid ester of novolac resin cannot be used together with a stepper that uses a 9-line light source, which has been widely used in recent years, and therefore improvements are desired.

This invention has been made in view of these points, and therefore, an object of the invention is to
An object of the present invention is to provide a resist material capable of obtaining a resist pattern having a desired inversely tapered shape.

(Means for Solving the Problems) In order to achieve this object, according to the present invention, in a resist material containing a naphthoquinonediazide sulfonic acid ester of a novolak resin, at least one substance having absorption in the 9-line wavelength region is added. It is characterized by containing more than one type.

Here, examples of substances having absorption in the wavelength region of line 9 include ethyl red represented by the above formula (I), and the above (II).
) Coumarin represented by the formula (nl), 1,4-Dis(2-methylstyryl) b represented by the above formula (nl)
enzen (referred to as Bis-MSB), 1-phenylazo-2- represented by the above formula (IV)
naphthol (abbreviated as Sudan I), triazine-based styryl represented by the above general formula (V), specifically, substances represented by the following formulas (a) to (C), and the above-mentioned formula (VI) Examples include a substance selected from the following: a substance represented by the above formula (■); a substance represented by the above formula (■); and a curcumin represented by the above formula (IX). However, substances that have absorption in the 9-line wavelength region are not limited to these, and other materials may be used as long as they do not impair the film forming properties of the resist and have absorption in the 9-line wavelength region. But it's okay.

Furthermore, if the content of a substance that absorbs in the 9-line wavelength region in the resist material is too low, the desired absorption will not be obtained, and if it is too high, only the surface layer of the resist layer will become insolubilized and the lower portion will be dissolved by the developer. If it is too much, you will not be able to obtain the desired resist button, so consider these factors and set the appropriate amount.

(Function) According to the resist material with such a configuration, since it contains a substance that absorbs in the 9-line wavelength region, the polarity change due to photoreaction is dominant at the surface of the resist layer and at a certain depth from the surface. As a result, this part becomes insoluble in the developer, and the solubility of the deeper part in the developer is maintained, so that the ratio of the solubility of both parts to the developer becomes large.

Therefore, although it is difficult for the developer to enter the contact hole, the developer that enters the contact hole easily dissolves the unexposed portion of the resist layer, making it easier to obtain an overhang-shaped resist pattern. .

(Example) Examples and comparative examples of the resist material of the present invention will be described below with reference to the drawings. In addition, Fig. 1 (A) - (
C) is a diagram for explaining an embodiment, in which a contact hole resist pattern 15 is formed on an insulating film (silicon oxide film in this case) 13 previously formed on a silicon substrate 11, and this resist pattern 15 is masked. A contact hole 13a is formed in the insulating film 13 by, for example, the RIE method.
3 is a cross-sectional view schematically showing the steps from forming a contact hole 13a to forming a wiring 17 through the contact hole 13a. Moreover, FIGS. 2(A) to 2(C) are diagrams for explaining a comparative example, and are process diagrams shown corresponding to the process diagrams of the example.

Dog 11 Milk 1 As Example 1, an example will be explained in which ethyl red represented by the following formula (I) is used as a substance having absorption in the wavelength region of 9 rays.

First, a resist material of Example 1 was prepared by dissolving 150 mq of ethyl red in a resist material prepared by dissolving naphthoquinonediazide sulfonic acid ester of 49 novolak resin in 9.9 methyl cellosolve acetate.

Next, the resist material of Example 1 is applied onto the insulating film 13 of the silicon substrate 11 having the insulating film 13 by spin coating. It was applied to a film thickness of 1.2 um, and then a prescribed baking treatment was performed. Next, use a mercury lamp (wavelength 4
Using a 115 reduction projection aligner as a light source (36 nm), exposure was performed through a mask with a predetermined contact hole pattern at an exposure dose of 200 mJ/cm2, and then LMR developer type C (Fuji Pharmaceutical Co., Ltd.) was used. Development was carried out using a developer (commercially available from Co., Ltd.). As a result, resist pattern 1 for a cositact hole with a diameter of 0.7 μm and an inverse taper angle θ1 of 60′ was obtained.
5 was formed (Fig. 1(A)).

Next, using this resist button 15 as a mask, using a reactive ion etching device N, high frequency, electric power 1.7 W, etching chamber pressure Tr 120 mTorr, C
HF3 gas flow rate is 11005cc, oxygen gas flow rate is 1
When etching was performed under the condition of 28CCM,
A contact hole 13a having a Taber angle θ2 of 73° was formed in the insulating film 13 (FIG. 1(B)).

After that, this contact hole 13a'@intermediate wiring 1
7, it was possible to form a wiring in which the arrangement line film thickness t at the edge portion of the contact hole was sufficiently thick and the step coverage was well eliminated, as shown in FIG. 1(C).

Large JLI property 2 150 mq of coumarin shown by the following formula (11) instead of ethyl red as a substance that has absorption in the wavelength region of 9 lines.
%, and otherwise prepared in the same manner as in Example].

Next, a resist pattern 15 for a contact hole was formed on the insulating film 13 on the silicon substrate 11 in the same manner as in Example 1 (see FIG. 1(A)). The obtained contact hole resist pattern 15 had an inverted Taper angle θ of 60°, as in Example 1.

Next, when the insulating film 13 was etched using the resist batten 15 as a mask under the same reactive ion etching conditions as in Example 1, a contact hole 13a with a Taber angle θ2 of 73° as in Example 1 was obtained. (
(See Figure 1 CB)).

Comparative Example 1 Resist material of Comparative Example in which naphthoquinonediazide sulfoshiic acid ester of Novolac resin No. 49 is dissolved in methyl cellosolve acetate of Example No. 99, that is, the same as above except that it does not contain any substance having absorption in the wavelength region of line 9. Resist materials similar to those in each Example were prepared.

Next, as shown in FIG. 2(A), the silicon substrate 11
A resist material of a comparative example was applied onto the above-mentioned R film 13 in the same manner as in the example], and exposed and developed in the same manner as in the example. The contact hole resist batten 21 obtained as a result had a reverse Taper angle θ3 of 80°, which was larger than that of the example, in other words, the overhang was small.

Next, when the insulating film 13 was etched using the resist batten 21 as a mask under the same reactive ion etching conditions as in Example 1, a contact hole 23 with a Taber angle θ4 of 85° and a steeper step than in the example was obtained ( Figure 2 (B)).

Thereafter, as shown in FIG. 2(C), a wiring 25 was formed through this contact hole 23, and this wiring 25 was formed through this contact hole 23.
It was found that in No. 5, the film thickness at the edge portion of the contact hole 23 was thinner than that of the example, and step breaks were likely to occur.

(Effects of the Invention) As is clear from the above explanation, the resist material of the present invention contains a substance that absorbs in the wavelength region of 9 lines, so that the resist material has a certain depth from the surface of the resist layer. The polarity change due to photoreaction occurs dominantly, and this part becomes insoluble in the developer, while the solubility of the deeper part in the developer is maintained, so the ratio of the solubility of both sections to the developer is large. Become. Therefore, although it is difficult for the developer to enter the contact hole, the developer that enters the contact hole easily dissolves the unexposed portion of the resist layer, making it easier to obtain an overhang-shaped resist button. .

Therefore, a resist batten having a desired inversely tapered shape can be obtained even by exposure using 9 lines.

[Brief explanation of the drawing]

FIGS. 1(A) to 1(C) are diagrams for explaining the resist material of the example, and are diagrams showing the process of forming a contact hole in an insulating film using this resist material, and then forming a wiring. , The second diagrams (A) to (C) are diagrams for explaining the resist material of the comparative example, and are process diagrams shown corresponding to the examples. 11... Silicon substrate, 13... Insulating film 13a
...Contact hole 15...Resist button 17 for contact hole...
- Wiring 21...Resist batten for contact hole of comparative example 23...Contact hole 25 of comparative example...Wiring of comparative example.

Claims (2)

[Claims] (1) A resist material containing naphthoquinonediazide sulfonic acid ester of novolak resin, which is characterized in that it contains at least one substance that absorbs in the G-line wavelength region. (2) The substance having absorption in the wavelength region of the g-line is ethyl red represented by the following formula (I), coumarin represented by the following formula (II), Bis-MSB represented by the following formula (III), or the following: Sudan I represented by formula (IV), triazine styryl represented by general formula (V) below (wherein R_1 in formula (V) is an aryl group or an aryl group having a substituent), formula (VI) below A substance represented by (wherein R_2 is 1,2-naphthoquinonediazide-5 represented by the following formula [1])
-Sulfonyl group, same in substance (VII) and substance (VIII) below. ), a substance represented by the following formula (VII), a substance represented by the following formula (VIII), and curcumin represented by the following formula (IX). ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼…(I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼…(II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼…(III) ▲ Mathematical formulas, chemical formulas, tables, etc. Yes▼...(IV) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(V) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(VI) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(VII) ▲Mathematical formulas , chemical formulas, tables, etc. ▼…(VIII) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼…[1] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼…(IX)