Agent for reducing the substrate dependence of resist

Details Agent for reducing the substrate dependence of resist Agent for reducing the substrate dependence of resist

1998-04-27

2001-10-16

Baxter, Janet (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Imaging affecting physical property of radiation sensitive...

Radiation sensitive composition or product or process of making

C430S905000

Reexamination Certificate

active

06303264

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to a substrate dependence reducing agent useful as the constituent of a chemical amplified type positive- or negative-working resist composition used for production of semiconductor devices, etc., a resist composition containing said agent, and a pattern formation process using the resist composition.
In place of a source of i-line light (365 nm), a KrF excimer laser having a shorter output wavelength of 248 nm has recently come to be used as a light source for exposure used in a lithography process because of a demand for ultramicrofabrication caused with an enhancement of the degree of integration of semiconductor devices. Consequently, conventional dissolution-inhibiting type resists which require exposure at several hundreds milli-joule have become unusable for, for example, the following reasons: no high energy can be obtained because the excimer laser is used in place of a mercury vapor lamp; and the resists strongly absorb light (namely, they are poor in transmittance) at 248 nm. Therefore, there have come to be used chemical amplified type resists which have a high transmittance even at 248 nm and permits pattern formation by exposure at several tens milli-joule.
The chemical amplified type resists, however, tend to be affected by a substrate because they have a reaction mechanism in which a dissolution-inhibiting compound such as an alkali-insoluble compound or an alkali-insoluble polymer becomes alkali-soluble owing to exposure energy during pattern formation, i.e., a two-step reaction mechanism in which an acid is generated from a photosensitive compound, on account of the exposure energy, and a chemical reaction is caused by the generated acid, so that the alkali-insoluble compound or polymer becomes alkali-soluble. That is, the decrease of the exposure dose enhances the influence of a subtle difference of the exposure dose in the boundary surface portion of the substrate and the influence of a basic substance and water which are released from the substrate. Therefore, in device production using the chemical amplified type resist, it becomes impossible to attain a good profile of pattern by using a special substrate (e.g. TiN, BPSG, etc.) which has been extraordinarily disadvantageous. Such substrate dependence is a serious problem.
For solving this problem, there have been proposed resist compositions containing an organic carboxylic acid (for example, JP-A 9-6001, JP-A 9-6002, JP-A 9-6003 and European Patent Laid-Open No. 679951), and it has been reported that the resist compositions improve a profile of pattern on a special substrate. These resist compositions containing an organic carboxylic acid, however, are disadvantageous in that since the organic carboxylic acid is utilized for causing a chemical reaction to reduce the substrate dependence, the resist compositions are strongly acidic and hence deteriorated in performance characteristics during storage. For alleviating this disadvantage, a basic compound should be added in an amount larger than that required for neutralizing the organic carboxylic acid, resulting in causing problems such as a sensitivity decrease, etc.
Accordingly, there is desired the development of a highly sensitive resist composition which gives a pattern with an excellent profile even on a special substrate and has an excellent storage stability and a satisfactory throughput.
SUMMARY OF THE INVENTION
In view of such conditions, a problem to be solved by the present invention is to provide a resist composition which gives a fine pattern with a good profile even on a special substrate in pattern formation using the resist composition as a chemical amplified type positive- or negative-working resist composition, has an excellent storage stability, and makes it possible to form a pattern with high sensitivity.
The present invention was made for solving the above problem and includes the following items.
(1) An agent for reducing the substrate dependence of a resist which comprises a compound containing in the molecule at least one structure in which at least one of the direct links of —NH— is directly bonded to at least one member selected from the group consisting of —C(═O)—, —C(═S)— and —SO
2
—.
(2) A resist composition comprising a polymer capable of becoming alkali-soluble owing to the action of an acid, a compound capable of generating an acid upon irradiation with actinic radiation, a compound containing in the molecule at least one structure in which at least one of the direct links of —NH— is directly bonded to at least one member selected from the group consisting of —C(═O)—, —C(═S)— and —SO
2
—, and a solvent capable of dissolving these three components.
(3) A resist composition comprising an alkali-soluble polymer, a compound capable of becoming alkali-soluble owing to the action of an acid, a compound capable of generating an acid upon irradiation with actinic radiation, a compound containing in the molecule at least one structure in which at least one of the direct links of —NH— is directly bonded to at least one member selected from the group consisting of —C(═O)—, —C(═S)— and —SO
2
—, and a solvent capable of dissolving these four components.
(4) A resist composition comprising an alkali-soluble polymer, a compound capable of making the polymer difficultly alkali-soluble by crosslinking therewith owing to the action of an acid, a compound capable of generating an acid upon irradiation with actinic radiation, a compound containing in the molecule at least one structure in which at least one of the direct links of —NH— is directly bonded to at least one member selected from the group consisting of —C(═O)—, —C(═S)— and —SO
2
—, and a solvent capable of dissolving these four components.
(5) A process for forming a pattern comprising a step of coating a semiconductor substrate with the resist composition described in any of the above items (2) to (4), a step of heating the coating to form a resist film, a step of exposing the resist film to radiation through a mask, and a step of developing the resist film with an alkali developing solution after heating the same if necessary.


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patent: 0 679 951 A1 (1995-11-01), None
patent: 0 704 762 A1 (1996-04-01), None
patent: 749046 (1996-06-01), None
patent: 0 780 732 A2 (1997-06-01), None
patent: 1059563-A1 (2000-12-01), None
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Aldrich Catalog 1996-1997, (pp. 139, 444, 534, 758, 1056, 1181, 1352, 1432) pertaining to specific chemical structures which can be used as reducing agents i.e., succinimde, phthalimide, and diacetamide.*
Derwent WPI—Abstract of JP9006002 A
Derwent WPI—Abstract of JP9006003 A
Derwent WPI—Abstract of EP 749046 A (family of JP9-6001).
Derwent WPI—Abstract of EP 679951 A (family of JP8-15864 and JP8 262721)

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