JP2626071B2 - Resist composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a resist composition. More specifically, the present invention relates to a resist composition particularly preferably used for forming a fine pattern on a high-reflectivity substrate such as aluminum in the manufacture of semiconductor devices such as ICs and LSIs.

<Prior Art> Conventionally, in the manufacture of integrated circuits such as LSIs, a resist composed of a quinonediazide-based photosensitive agent and a novolak-based resin, a resist composed of a bisazide-based photosensitive agent and a cyclized rubber-based resin, and the like have been used.

In the manufacture of integrated circuits, a fine pattern is formed using a resist on various substrates, but on high reflectance substrates such as aluminum, aluminum-silicon, and polysilicon,
In a conventional resist, an unnecessary area is exposed to light due to reflection of light on a substrate surface or a step side surface, and a problem such as so-called notching or halation occurs.

In order to improve the above problem and prevent the resolution from decreasing, Japanese Patent Publication No. Sho 51-37562 discloses the following formula having an absorption characteristic in the ultraviolet region. There has been proposed a resist composition containing a dye (oil yellow [CI-11020]) as a light absorber.
Thereby, the light passing through the resist tank can be rapidly reduced, and the sneak of the light into the light-shielding region can be reduced.

Hereinafter, in the present invention, a composition comprising a resin such as a novolak resin and a photosensitizer is referred to as a “resist”, and a composition containing a light absorbing agent is referred to as a “resist composition”.

In general, the addition of a light-absorptive material causes an undesired problem that the sensitivity of the resist is greatly reduced, and the productivity during the production of semiconductors is reduced.

Usually, a resist film is prepared by applying a solvent-containing resist composition to a wafer and pre-baking to remove the solvent.However, depending on the light-absorbing agent, it may precipitate during storage or sublime during pre-baking. Therefore, there is a problem that the concentration is lowered and the resist performance varies.

<Problems to be Solved by the Invention> The inventors of the present invention have made intensive studies to overcome the above-mentioned disadvantages of the prior art, and as a result, have completed the present invention.

That is, an object of the present invention is to eliminate the drawbacks of the prior art, to form a high-resolution pattern on a high-reflectance substrate without halation or notching, and also stable against pre-baking, and a light-absorbing agent. An object of the present invention is to provide a high-sensitivity resist composition in which a decrease in sensitivity due to addition is small.

Another object of the present invention is to contain a light absorbing agent having good compatibility with the resist, and the light absorbing agent does not precipitate in the resist composition during storage or in the resist composition film after coating and pre-baking. An object of the present invention is to provide a resist composition for fine processing.

<Means for Solving the Problems> As a result of intensive studies, the present inventors have found that the use of the compound of the general formula (I) as a light-absorbing agent can alleviate the drawbacks of the prior art at a glance. The invention has been completed.

That is, the present invention provides a compound represented by the general formula (I): (Wherein R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ each independently represent hydrogen, an alkoxy group having 1 to 6 carbon atoms, or a hydroxy group). Resist composition. It is more preferable that one or two of R _{1 to} R ₅ are hydroxy groups.

The compound of the general formula (I) can be obtained from J. Chem. Soc., Perkin Trans.
1, (7), 1555-1560 (1980) and the like. That is, it can be synthesized by a condensation reaction between the compound of the formula (II) and the compound of the formula (III).

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ have the same meanings as described above.) Examples of the compound of the general formula (I) include the following compounds. The compounds are not limited, and these compounds can be used as a mixture of two or more kinds.

As the resist serving as the base material of the resist composition used in the present invention, for example, a resist comprising a novolak resin obtained by subjecting a phenol and formaldehyde to an addition condensation reaction and a naphthoquinonediazide compound is suitably used. Among them, cresol novolak resins synthesized from m-cresol and / or p-cresol and formalin or cresol-based novolak resins synthesized from m-, p-cresol and 3,5-xylenol and formalin, and 2,3,4 -Trihydroxybenzophenone, 2,3,4,4 '
-Tetrahydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,3,3', 4-tetrahydroxybenzophenone, 2,2 ', 3,4,5-pentahydroxybenzophenone, 2,3 , 3 ', 4,5-pentahydroxybenzophenone, 2,3,3', 4,4'-pentahydroxybenzophenone, 2,2 ', 3,4,4'-pentahydroxybenzophenone, 2,2', 3 A resist containing naphthoquinone-1,2-diazidosulfonic acid ester of polyhydroxybenzophenones such as 3,3 ', 4-pentahydroxybenzophenone is preferably used.

The amount of the compound represented by the general formula (I) in the resist composition of the present invention is usually based on the solid content of the resist.
It is 0.1 to 20%, more preferably 0.2 to 10%. If the amount is too small, the effect of preventing halation is small, and if it is too large, the profile and sensitivity tend to deteriorate.
In the composition of the present invention, in addition to the compound of the present invention,
One or more other compounds can be used in combination.

Among these compounds of the present invention, especially 550 nm or less,
More preferably, a compound having an absorption maximum for light in the region of 300 to 450 nm is preferably used.

<Effects of the Invention> According to the present invention, the disadvantages of the prior art are eliminated at once, and a high-resolution pattern without halation or notching can be stably formed on a high-reflectivity substrate without lowering productivity. Its industrial utility value is immeasurable, as it can be formed.

<Examples> Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Examples 1-2 and Comparative Examples 1-2 Positive resist PF-6200 containing a novolak resin and at least one o-quinonediazide compound (trade name, manufactured by Sumitomo Chemical Co., Ltd., solid content ratio: 31.0 wt%) Table 2
Was added to prepare a resist composition.
However, in Comparative Example 2, the above-mentioned positive resist PF-6200 was used as it was. The compounds of Examples 1 and 2
It was synthesized by the method shown above. The amount of each compound added is 365n
The absorbance of the resist composition at m was set to be the same as that of Comparative Example 1 (1.0 wt% of the compound was added based on the solid content of the resist).

These resist compositions were spin-coated on a 4-inch silicon wafer with an aluminum film by a spinner so as to have a thickness of 1.8 μm, and prebaked at 100 ° C. for 1 minute on a hot plate. This was exposed using a reduction projection exposure apparatus (exposure wavelength i-line: 365 nm) with a stepwise changing exposure amount via a test reticle. Furthermore, SOPD (trade name, Sumitomo Chemical Co., Ltd., positive resist developer)
Was developed by an automatic developing machine at 23 ° C. for 60 seconds using a stationary paddle method.

Table 2 shows the evaluation results of the obtained resist patterns. In this table, the relative sensitivity is a ratio when the exposure amount required for resolving the resist film of Comparative Example 2 is 1, and the absorbance is 1 at 365 nm. Is the ratio when The antihalation effect was evaluated by the following method.

[Evaluation method of halation prevention effect]

1. Production of Stepped Substrate for Evaluation A stepped pattern having the shape shown in FIG. 1 was formed on a silicon substrate having a 1 μm thick SiO ₂ film by photolithography, etching and aluminum sputtering. Typical pattern sizes are a = 4 μm, b =
2 μm, c = 1 μm, and d = 1 μm.

2. Evaluation of antihalation effect A 1.8 μm-thick resist film is formed by spin coating on the high-reflectivity stepped substrate prepared by the above method. The line width (x) of the portion having no step shown in FIG. 2 is 1.2 μm across the central concave portion of the step pattern shown in FIG.
Exposure and development are performed so that m resist lines are formed. The line width (y) of the resist remaining at the center of the stepped recess after the exposure and development was measured, and the reduction ratio of y to x [R = (x−
y) / x].

When the reduction rate (R) of the line width is within 10%, the halation prevention effect is determined to be “excellent”, and when it is 11 to 20%, it is determined to be “good”.
21% or more are judged as "bad".

As shown in Table 2, in the example, a pattern was formed with high sensitivity. It was found that the formed pattern was sharply resolved, had no notch due to reflected light on the side surface of the pattern, and was excellent in the effect of preventing halation from the aluminum surface.

On the other hand, the resist of Comparative Example was insufficient in sensitivity or antihalation effect.

[Brief description of the drawings]

FIG. 1 is an evaluation step pattern shape diagram. FIG. 2 is a view showing the application, exposure, and development of a resist.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yasunori Uetani 3-1-1, Kasuganaka, Konohana-ku, Osaka-shi, Osaka Sumitomo Chemical Industries Co., Ltd. (72) Takanori Yamamoto Kasuga, Konohana-ku, Osaka-shi, Osaka Naka 3-chome No. 1 98 Sumitomo Chemical Co., Ltd. (56) References JP-A-63-136040 (JP, A)

Claims (1)

(57) [Claims] 1. The compound of the general formula (I) Wherein R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ each independently represent hydrogen, an alkoxy group having 1 to 6 carbon atoms, or a hydroxy group. Composition.