阅读说明：本技术 正型抗蚀剂组合物和使用该正型抗蚀剂组合物的抗蚀剂图案的制造方法 (Positive resist composition and method for producing resist pattern using same ) 是由 明石一通 浦部慈子 张锐 片山朋英 于 2020-03-26 设计创作，主要内容包括：提供一种能够形成适合剥离的图案形状的正型抗蚀剂组合物。一种正型抗蚀剂组合物,其包含(A)特定的聚合物、(B)具有酰亚胺基的产酸剂、(C)溶解速度调节剂,和(D)溶剂。(Provided is a positive resist composition capable of forming a pattern shape suitable for stripping. A positive resist composition comprising (A) a specific polymer, (B) an acid generator having an imide group, (C) a dissolution rate modifier, and (D) a solvent.)

1. A positive resist composition comprising:

(A) at least one polymer selected from the group consisting of polymer P and polymer Q,

the polymer P contains a repeating unit selected from the group consisting of formulas (P-1) to (P-4):

in the formula (I), the compound is shown in the specification,

R^p1、R^p3、R^p5and R^p8Each independently is C_1-5Alkyl radical, C_1-5An alkoxy group or-COOH group or a group,

R^p2、R^p4and R^p7Each independently is C_1-5Alkyl, here, -CH in alkyl₂-can be replaced by-O-,

R^p6and R^p9Each independently is C_1-5Alkyl, here, -CH in alkyl₂-can be replaced by-O-,

x1 is 0 to 4, x2 is 1 to 2, wherein x1+ x2 is less than or equal to 5,

x3 is 0 to 5,

x4 is 1 to 2, x5 is 0 to 4, wherein x4+ x5 is less than or equal to 5,

the polymer Q comprises a repeating unit represented by the formula (Q-1):

in the formula (I), the compound is shown in the specification,

R^q1each independently is C_1-5An alkyl group, a carboxyl group,

y1 is 1-2, y2 is 0-3, wherein y1+ y2 is not more than 4

Wherein the total mass M of the polymer P in the composition_pAnd the total mass M of the polymer Q_qSatisfies the following conditions: 0<M_p/(M_p+M_q) 100% or less, and 0 or less M_q/(M_p+M_q)<70％；

(B) An acid generator having an imide group;

(C) a dissolution rate modifier which is a compound in which two or more phenol structures are linked through a hydrocarbon group, the hydrocarbon group being optionally substituted with an oxy group; and

(D) a solvent.

2. The composition of claim 1, wherein 10 ≦ M_q/(M_p+M_q)≤60％。

3. The composition of claim 1 or 2, wherein polymer Q comprises a repeat unit selected from formulae (Q-1a) to (Q-1 d):

number N of repeating units of (Q-1a)_qaThe number N of repeating units of (Q-1b)_qbThe number N of repeating units of (Q-1c)_qcThe number N of repeating units of (Q-1d)_qdSatisfies the following formula:

30％≤N_qa/(N_qa+N_qb+N_qc+N_qd)≤100％；

0％≤N_qb/(N_qa+N_qb+N_qc+N_qd)≤70％；

0％≤N_qc/(N_qa+N_qb+N_qc+N_qd) Less than or equal to 50 percent; and is

0％≤N_qd/(N_qa+N_qb+N_qc+N_qd)≤70％。

4. Composition according to at least one of claims 1 to 3, wherein the composition further comprises (E) an alkaline compound, preferably the composition further comprises (F) a plasticizer.

5. The composition according to at least one of claims 1 to 4, wherein the content of the acid generator (B) is 0.1 to 10.0% by mass based on the total mass of the polymer (A),

preferably, the content of the (A) polymer is 10 to 50% by mass based on the total mass of the composition,

preferably, the content of the (C) dissolution rate modifier is 0.1 to 20% by mass based on the total mass of the (A) polymer,

preferably, the content of the (D) solvent is 40 to 90% by mass based on the total mass of the composition,

preferably, the content of the (E) basic compound is 0 to 1.0 mass% based on the total mass of the (A) polymer,

preferably, the content of the (F) plasticizer is 0 to 30% by mass based on the total mass of the (A) polymer.

6. The composition according to at least one of claims 1 to 5,

(B) the acid generator is represented by formula (b):

in the formula (I), the compound is shown in the specification,

R^b1each independently is C_3-10Alkenyl or alkynyl (wherein CH in alkenyl and alkynyl₃-CH which may be substituted by phenyl and which is in alkenyl and alkynyl₂-may be replaced by-C (═ O) -, -O-or phenylene), C_2-10Thioalkyl, C_5-10A saturated heterocyclic ring,

nb is 0, 1 or 2, and

R^b2is C_1-5A fluoro-substituted alkyl group of (a);

(C) the dissolution rate modifier is represented by formula (c):

in the formula (I), the compound is shown in the specification,

nc1 are each independently 1,2 or 3,

nc2 are each independently 0, 1,2 or 3,

R^c1each independently is C_1-7The alkyl group of (a) is,

L^cis C_1-15A divalent alkylene group of (a), which may be substituted by a hydroxyl groupAryl substituted, which may be with L^cSubstituents other than these form a ring;

(E) the basic compound is selected from ammonia and C_1-16Aliphatic primary amine, C_2-32Aliphatic Secondary amine, C_3-48Aliphatic tertiary amine, C_6-30Aromatic amine, and C_5-30Heterocyclic amines and derivatives thereof;

(F) the plasticizer is a compound containing a structural unit represented by the formula (f-1) and/or a structural unit represented by the formula (f-2):

in the formula (I), the compound is shown in the specification,

R^f1each independently is hydrogen or C_1-5And is an alkyl group of

R^f2Each independently is hydrogen or C_1-5The alkyl group of (a) is,

in the formula (I), the compound is shown in the specification,

R^f3each independently is hydrogen or C_1-5Alkyl of R^f4Is hydrogen or C_1-5And is an alkyl group of

R^f5Is C_1-5Alkyl group of (1).

7. The composition according to at least one of claims 1 to 6, wherein the viscosity of the composition is 50 to 2,000cP at 25 ℃.

8. The composition according to at least one of claims 1 to 7, which is a positive resist composition forming an inverted cone shape.

9. The composition according to at least one of claims 1 to 8, which is a positive resist stripping composition.

10. A method of manufacturing a resist pattern, comprising the steps of:

(1) applying the composition according to at least one of claims 1 to 7 on a substrate;

(2) heating the composition to form a resist layer;

(3) exposing the resist layer;

(4) heating the resist layer after exposure; and

(5) and developing the resist layer.

11. The method according to claim 10, wherein the resist pattern has a film thickness of 1 to 50 μm.

12. The method according to claim 10 or 11, wherein the resist pattern has an inverted cone shape.

13. A method of manufacturing a metal pattern, comprising:

manufacturing a resist pattern according to the method of claim 10;

(6) evaporating metal on the substrate by taking the resist pattern as a mask; and

(7) the resist pattern is removed with a stripping liquid.

14. The method according to claim 11, wherein the metal pattern has a film thickness of 0.01 to 40 μm.

15. A method of manufacturing a device comprising a method according to at least one of claims 10 to 14.

Technical Field

The present invention relates to a positive resist composition for use in the production of semiconductor devices, semiconductor integrated circuits, and the like, and a method for producing a resist pattern using the positive resist composition.

Background

In the manufacturing process of a device such as a semiconductor, fine processing is generally performed by a photolithography technique using a photoresist. The fine processing step is to form a thin photoresist layer on a semiconductor substrate such as a silicon wafer, cover the layer with a mask pattern corresponding to the pattern of a target device, expose the layer with active light such as ultraviolet rays through the mask pattern, obtain a photoresist pattern by developing the exposed layer, process the substrate using the obtained photoresist pattern as a protective film, and thereby form fine irregularities corresponding to the pattern.

When a positive resist composition is used, an exposed portion of a resist film formed by coating increases in alkali solubility due to acid generated by exposure, and is dissolved in a developer to form a pattern. In general, the exposure light does not sufficiently reach the lower portion of the resist film, the generation of acid is suppressed at the lower portion of the resist film, and the generated acid is inactivated at the lower portion of the resist film by the influence of the substrate. Therefore, a resist pattern formed by using a positive resist composition tends to have a tapered shape (footing shape) (patent document 1).

There is known a lift-off method in which, when a material such as metal is evaporated on a formed resist pattern by vapor deposition or the like and the resist is removed with a solvent, the material on the resist pattern is removed, and only a portion where the resist pattern is not formed remains with the material such as metal.

In order to perform the lift-off method, a negative resist composition is often used because a resist pattern having a reverse taper shape is preferable. In patent document 2, in order to manufacture a partition wall of an EL display element instead of a semiconductor, an attempt is made to form a reverse tapered shape, although the required accuracy and sensitivity are different depending on the process. However, all of the resist compositions used were negative type, and only some of them achieved reverse taper.

On the other hand, it is studied to produce undercuts at the bottom of a resist pattern obtained from a positive resist composition to form a T-shape (for example, patent documents 3 to 5). These compositions require either special polymers or novolak resins and naphthoquinone diazide type photosensitizers.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2011/102064

Patent document 2: japanese laid-open patent publication No. 2005-148391A

Patent document 3: japanese laid-open patent publication No. 2012-108415A

Patent document 4: japanese laid-open patent publication No. 2001-235872A

Patent document 5: japanese unexamined patent publication No. 8-69111A

Disclosure of Invention

Problems to be solved by the invention

The present inventors have recognized that there are still one or more problems that need to be improved with respect to resist compositions and uses thereof. They include, for example: resist pattern shapes suitable for lift-off cannot be formed; insufficient sensitivity of the resist composition; sufficient resolution cannot be obtained; environmental impact during resist pattern fabrication; resist patterns that do not produce thick films; the solubility of the solid component in the solvent is poor; in a T-type resist pattern, when the evaporated metal is thick, the stripper cannot penetrate the resist sidewall; low solubility in the stripping solution; resist patterns having a high aspect ratio cannot be formed; the resist film has many cracks; the number of defects is large; the storage stability was poor.

The present invention has been made to solve the above problems, and provides a positive resist composition and a method for producing a resist pattern using the same.

Means for solving the problems

The positive thick film resist composition according to the invention comprises:

(A) at least one polymer selected from the group consisting of polymer P and polymer Q,

the polymer P contains a repeating unit selected from the group consisting of formulas (P-1) to (P-4):

(in the formula, wherein,

R^p1、R^p3、R^p5and R^p8Each independently is C_1-5Alkyl radical, C_1-5An alkoxy group or-COOH group or a group,

R^p2、R^p4and R^p7Each independently is C_1-5Alkyl (here, — CH in alkyl)₂-may be replaced by-O-),

R^p6and R^p9Each independently is C_1-5Alkyl (here, — CH in alkyl)₂-may be replaced by-O-),

x1 is 0 to 4, x2 is 1 to 2, wherein x1+ x2 is less than or equal to 5,

x3 is 0 to 5,

x4 is 1 to 2, x5 is 0 to 4, wherein x4+ x5 is less than or equal to 5),

the polymer Q comprises a repeating unit represented by the formula (Q-1):

(in the formula, wherein,

R^q1each independently is C_1-5An alkyl group, a carboxyl group,

y1 is 1 to 2, y2 is 0 to 3, wherein y1+ y2 is not more than 4)

Wherein the total mass M of the polymer P in the composition_pAnd the total mass M of the polymer Q_qSatisfies the following conditions: 0<M_p/(M_p+M_q) 100% or less, and 0 or less M_q/(M_p+M_q)<70％；

(B) An acid generator having an imide group;

(C) a dissolution rate modifier which is a compound in which two or more phenol structures are linked through a hydrocarbon group, which may be substituted with an oxy group; and

(D) a solvent.

In addition, the method for manufacturing a resist pattern according to the present invention includes the steps of:

(1) applying the composition over a substrate;

(2) heating the composition to form a resist layer;

(3) exposing the resist layer;

(4) heating the resist layer after exposure; and

(5) and developing the resist layer.

ADVANTAGEOUS EFFECTS OF INVENTION

By using the positive resist composition of the present invention, one or more of the following effects can be obtained.

A resist pattern shape suitable for lift-off can be formed. The sensitivity of the resist composition is sufficient. Sufficient resolution can be obtained. The influence on the environment can be reduced in the resist pattern manufacturing process. A thick film resist pattern can be fabricated. The solid content was good in solubility in the solvent. Even if the evaporated metal is thick, a resist pattern shape allowing the resist sidewall to be penetrated by the stripping liquid can be obtained. Has high solubility in the stripping solution. A resist pattern having a high aspect ratio can be formed. Cracks in the resist film can be suppressed. The number of defects can be reduced. Good storage stability.

The invention has the advantages of high solubility in stripping liquid and proper shape of resist pattern.

Drawings

Fig. 1 is a conceptual sectional view for explaining a modified example of a resist pattern having an inverted conical shape, a resist pattern having an overhanging (overhanging) shape, and a resist pattern having an overhanging shape.

Fig. 2 is a photomicrograph of a resist pattern having an inverted pyramidal shape and a schematic sectional view thereof.

Detailed Description

Definition of

In the present specification, the definitions described in this "definition" paragraph are followed unless specifically mentioned by limitation.

The singular forms "a", "an" and "the" include plural forms and mean "at least one". In the present specification, some conceptual elements may be embodied by various types, and if an amount thereof (for example, mass% or mol%) is described, the amount means a sum of the various types.

"and/or" includes all combinations of elements and also includes use alone.

When "-" or "-" is used to indicate a numerical range, they include both endpoints unless specifically mentioned by limitation, and the units are common. For example, 5 to 25 mol% means 5 mol% or more and 25 mol% or less.

“C_x-y”、“C_x～C_y"and" C_xThe description of "etc. refers to the number of carbons in a molecule or substituent. E.g. C_1-6The alkyl group represents an alkyl chain having 1 to 6 carbons (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, etc.).

If the polymer has multiple repeat units, these repeat units are copolymerized. These copolymerizations may be alternating copolymerization, random copolymerization, block copolymerization, graft copolymerization, or a mixture thereof. When a polymer or a resin is represented by a structural formula, n, m, etc. shown together in parentheses represent the number of repetitions.

The temperature units are given in degrees Celsius (Celsius). For example, 20 degrees means 20 degrees celsius.

Hereinafter, embodiments of the present invention will be described in detail.

< Positive resist composition >

A positive resist composition according to the present invention (hereinafter, may be referred to as a composition) includes (a) a specific polymer, (B) an acid generator having an imide group, (C) a dissolution rate modifier, and (D) a solvent.

The viscosity of the composition according to the present invention is preferably 50 to 2,000cP, more preferably 200 to 1,500 cP. Here, the viscosity was measured at 25 ℃ with a capillary viscometer.

The composition according to the invention is preferably a thick film resist forming composition. In the present invention, the thick film is a film thickness of 1 to 50 μm, preferably 5 to 15 μm, and the thin film is a film thickness of less than 1 μm.

The composition according to the invention is preferably subjected to a subsequent exposure using light having a wavelength of 190 to 440nm, preferably 240 to 440nm, more preferably 360 to 440nm, even more preferably 365 nm.

The composition according to the present invention is preferably a positive type resist composition forming an inverted conical shape. In the present invention, the "reverse tapered shape" will be described below.

The composition according to the present invention is preferably a positive resist stripping composition.

(A) Polymer and method of making same

(A) The polymer comprises polymer P, or a combination of polymer P and polymer Q. It goes without saying that when both the polymer P and the polymer Q are contained, they are not copolymerized.

[ Polymer P ]

The polymer P used in the present invention reacts with an acid to increase its solubility in an alkaline aqueous solution. Such a polymer has, for example, an acid group protected by a protecting group, and when an acid is added from the outside, the protecting group is removed and the solubility in an aqueous alkaline solution increases.

The polymer P comprises repeating units selected from the group consisting of formulae (P-1) to (P-4).

(in the formula, wherein,

R^p1、R^p3、R^p5and R^p8Each independently is C_1-5Alkyl radical, C_1-5An alkoxy group or-COOH group or a group,

R^p2、R^p4and R^p7Each independently is C_1-5Alkyl (here, — CH in alkyl)₂-may be replaced by-O-),

R^p6and R^p9Each independently is C_1-5Alkyl (here, — CH in alkyl)₂-may be replaced by-O-),

x1 is 0 to 4, x2 is 1 to 2, wherein x1+ x2 is less than or equal to 5,

x3 is 0 to 5,

x4 is 1-2, x5 is 0-4, wherein x4+ x5 is less than or equal to 5.

One embodiment of the polymer P of the invention comprises only (P-1) as structural unit, and the ratio of (P-1) with x2 ═ 1 to (P-1) with x2 ═ 2 is 1: 1. In this case, x2 is 1.5. As to the polymer, those which are not particularly mentioned hereinafter are also applicable.

In the formula (P-1),

R^p1hydrogen and methyl are preferred, and hydrogen is more preferred. R^p2Preferably methyl, ethyl, tert-butyl or methoxy, more preferably methyl or tert-butyl.

x2 is preferably 1 or 2, more preferably 1.

x1 is preferably 0, 1,2 or 3, more preferably 0.

Specific examples of the formula (P-1) are as follows.

In the formula (P-2),

R^p3preferably hydrogen or methyl, more preferably hydrogen. R^p4Preferably methyl, ethyl, tert-butyl or methoxy, more preferably methyl or tert-butyl.

x3 is preferably 0, 1,2 or 3, more preferably 0.

Specific examples of the formula (P-2) are as follows.

In the formula (P-3),

R^p5preferably hydrogen or methyl, more preferably hydrogen. R^p6Preferably methyl, ethyl, propyl, tert-butyl, -CH (CH)₃)-OC₂H₅or-CH (CH)₃)-O-CH₃More preferably methyl, butyl, -CH (CH)₃)-OC₂H₅or-CH (CH)₃)-O-CH₃More preferably tert-butyl or-CH (CH)₃)-O-C₂H₅。R^p7Preferably methyl, ethyl, tert-butyl or methoxy, more preferably methyl or tert-butyl.

x4 is preferably 1 or 2, more preferably 1.

x5 is preferably 0, 1,2 or 3, more preferably 0.

Specific examples of the formula (P-3) are as follows.

In the formula (P-4),

R^p8preferably hydrogen or methyl, more preferably hydrogen. R^p9Preferably methyl, ethyl, propyl or tert-butyl, more preferably tert-butyl.

Specific examples of the formula (P-4) are as follows.

Since these structural units are appropriately blended according to the purpose, the blending ratio is not particularly limited, and it is preferable to blend them so that the ratio of the solubility in an alkaline aqueous solution is increased by an acid.

Preferably, in the polymer (A), the number of repeating units of the formulae (P-1), (P-2), (P-3) and (P-4) is n_p1、n_p2、n_p3And n_p4Preferably, the following formula is satisfied:

30％≤n_p1/(n_p1+n_p2+n_p3+n_p4)≤90％，

0％≤n_p2/(_p1+n_p2+n_p3+n_p4)≤40％，

0％≤n_p3/(n_p1+n_p2+n_p3+n_p4) Less than or equal to 40%, and

0％_≤np4/(_np1+_np2+_np3+_np4)≤40％。

n_p1/(n_p1+n_p2+n_p3+n_p4) More preferably 40 to 80%, and still more preferably 40 to 70%.

n_p2/(n_p1+n_p2+n_p3+n_p4) More preferably 0 to 30%, and still more preferably 10 to 30%.

n_p3/(n_p1+n_p2+n_p3+n_p4) More preferably 0 to 30%, and still more preferably 10 to 30%. n is_p3/(n_p1+n_p2+n_p3+n_p4) 0% is also a preferred form.

n_p4/(n_p1+n_p2+n_p3+n_p4) More preferably 10 to 40%, and still more preferably 10 to 30%.

Furthermore, (n)_p3+n_p4)/(n_p1+n_p2+n_p3+n_p4) Preferably 0 to 40%, more preferably 0 to 30%, and still more preferably 10 to 30%. In the polymer P, it is also preferred that one of the recurring units of the formulae (P-3) and (P-4) is present and the other is absent.

The polymer P may contain a structural unit other than (P-1) to (P-4). Here, the total number n of all repeating units contained in the polymer P_totalCalculated from the following formula:

preferably, 80% ≦ (_np1+_np2+_np3+_np4)/n_total≤100％。

(n_p1+n_p2+n_p3+n_p4)/n_totalMore preferably 90 to 100%, and still more preferably 95 to 100%. (n)_p1+n_p2+n_p3+n_p4)/n_totalThat is, the compound does not contain a structural unit other than (P-1) to (P-4), which is 100%, is also a preferred form of the present invention.

Specific examples of the polymer P are as follows.

The mass average molecular weight (hereinafter sometimes referred to as Mw) of the polymer P is preferably 5,000 to 50,000, more preferably 7,000 to 30,000, and still more preferably 10,000 to 15,000.

In the present invention, Mw can be measured by Gel Permeation Chromatography (GPC). In this measurement, tetrahydrofuran, which is an elution solvent at 40 ℃ and 0.6mL/min, is used as a GPC column, and monodisperse polystyrene is used as a standard. The same applies to the following.

[ Polymer Q ]

The polymer Q used in the present invention is a novolak polymer generally used in photolithography, and is obtained by, for example, a condensation reaction of a phenol and formaldehyde.

The polymer Q contains a repeating unit represented by the formula (Q-1).

In the formula (I), the compound is shown in the specification,

R^q1each independently is C_1-5An alkyl group, a carboxyl group,

y1 is 1 to 2,

y2 is 0-3, wherein y1+ y2 is less than or equal to 4.

y1 is preferably 1 or 2, more preferably 1.

y2 is preferably 0 to 2, more preferably 0.5 to 1.5.

The polymer Q preferably comprises repeating units selected from the group consisting of the formulae (Q-1a) to (Q-1 d).

Number N of repeating units of (Q-1a)_qaThe number N of repeating units of (Q-1b)_qbThe number N of repeating units of (Q-1c)_qcThe number N of repeating units of (Q-1d)_qdPreferably satisfying the following formula:

30％≤N_qa/(N_qa+N_qb+N_qc+N_qd)≤100％，

0％≤N_qb/(N_qa+N_qb+N_qc+N_qd)≤70％，

0％≤N_qc/(N_qa+N_qb+N_qc+N_qd) Less than or equal to 50%, and

0％≤N_qd/(N_qa+N_qb+N_qc+N_qd)≤70％。

N_qa/(N_qa+N_qb+N_qc+N_qd) More preferably 30 to 80%, further preferably 30 to 70%, and even more preferably 40 to 60%.

N_qb/(N_qa+N_qb+N_qc+N_qd) More preferably 10 to 60%, still more preferably 20 to 50%, and still more preferably 30 to 50%.

N_qc/(N_qa+N_qb+N_qc+N_qd) More preferably 0 to 40%, and still more preferably 10 to 30%. N is a radical of_qc/(N_qa+N_qb+N_qc+N_qd) 0% is also a preferred form.

N_qd/(N_qa+N_qb+N_qc+N_qd) More preferably 0 to 40%, and still more preferably 10 to 30%. N is a radical of_qd/(N_qa+N_qb+N_qc+N_qd) 0% is also a preferred form. In the polymer Q, it is also preferred that one of the repeating units of the formulae (Q-1c) and (Q-1d) is present and the other is absent.

The polymer Q may contain structural units other than (Q-1a) to (Q-1 d). Here, the total number N of all repeating units contained in the polymer Q_totalPreferably, the following formula is satisfied:

80％≤(N_qa+N_qb+N_qc+N_qd)/N_total≤100％。

(N_qa+N_qb+N_qc+N_qd)/N_totalmore preferably 90 to 100%, and still more preferably 95 to 100%. (N)_qa+N_qb+N_qc+N_qd)/N_totalWhen the content is 100%, that is, when the content does not contain any structural unit other than (Q-1a) to (Q-1d), the present invention is also a preferred embodiment.

The mass average molecular weight (hereinafter, sometimes referred to as Mw) of the polymer Q is preferably 1,000 to 50,000, more preferably 2,000 to 30,000, and still more preferably 3,000 to 10,000.

The total mass M of the polymers P in the composition_pAnd the total mass M of the polymer Q_qPreferably, the formula is satisfied: 0<M_p/(M_p+M_q) 100% or less, more preferably 40. ltoreq. M_p/(M_p+M_q)≤90％。

Further, it is preferable that 0. ltoreq. M is satisfied_q/(M_p+M_q)<70%, more preferably 10. ltoreq. M_q/(M_p+M_q)≤60％。

The polymer Q is a polymer having a higher alkali solubility than the polymer P. In the polymer (a), the polymer Q may not be contained, but if the polymer Q is contained, the resist pattern tends to have an overhang shape shown in (B) of fig. 1 described later. However, since the alkali solubility of the polymer Q is high, when the content of the polymer Q is 70% or more with respect to the total mass of the polymers P and Q, the sectional shape of the resist pattern tends to be close to a taper shape, and thus attention is required.

(A) The polymer may include polymers other than polymer P and polymer Q. The content of the polymer other than the polymers P and Q is preferably 60% or less, more preferably 30% or less, based on the total mass of the polymer (a). Polymers other than polymer P and polymer Q are not copolymerized with polymer P or polymer Q.

The condition for the polymer containing the repeating unit selected from the above formulas (P-1) to (P-4) is not satisfied for the polymers other than the polymer P and the polymer Q, and further, the condition for the polymer containing the repeating unit represented by the above formula (Q-1) is not satisfied.

Polymers other than polymer P and polymer Q are also preferred forms of the invention.

The content of the polymer (A) is preferably 10 to 50% by mass, more preferably 30 to 40% by mass, based on the total mass of the composition.

(B) Acid generator having imide group

The composition according to the present invention contains (B) an acid generator having an imide group (hereinafter, sometimes referred to as (B) an acid generator). The acid generator (B) releases an acid by irradiation with light, and the acid acts on the polymer P to improve the solubility of the polymer in an alkaline aqueous solution. For example, if the polymer has an acid group protected by a protecting group, the protecting group is removed by an acid.

In the present invention, the (B) acid generator means a compound itself having the above-described function. The compound may be dissolved or dispersed in a solvent and contained in the composition, but such a solvent is preferably contained in the composition as the (D) solvent or other component. Hereinafter, the same applies to various additives that may be contained in the composition.

The imide group in the present invention means a group having a structure of-N, but preferably has a structure of-C (═ O) -N (-Z) -C (═ O) - (here, Z is an organic group) in which a nitrogen atom is present between two carbonyl groups.

Preferably, the composition according to the present invention is substantially free of diazonaphthoquinone derivatives and quinone diazide sulfonate type photosensitizers (hereinafter referred to as diazonaphthoquinone derivatives and the like in this paragraph) which are generally used as photosensitizers for phenolic resin polymers. In the prior art of patent documents 1 to 3, a diazonaphthoquinone derivative or the like is exposed to light to form a carboxylic acid, which is used to increase the alkali solubility of the exposed portion. On the other hand, in the unexposed portion (the portion not exposed to light), the diazonaphthoquinone derivative is considered to increase the molecular weight of the phenolic resin polymer and contribute to the suppression of dissolution.

The composition according to the present invention contains a diazonaphthoquinone derivative or the like, the sectional shape of the resist pattern tends to be nearly tapered. Therefore, the composition according to the present invention preferably does not contain diazonaphthoquinone derivatives and the like.

(B) The acid generator is preferably represented by formula (b).

In the formula (I), the compound is shown in the specification,

R^b1each independently is C_3-10Alkenyl or alkynyl (wherein CH in alkenyl and alkynyl₃-CH which may be substituted by phenyl and which is in alkenyl and alkynyl₂-may be replaced by-C (═ O) -, -O-or phenylene), C_2-10Thioalkyl, C_5-10A saturated heterocyclic ring.

nb is 0, 1 or 2, and

R^b2is C_1-5Fluorine substituted alkyl of (a). Here, in the fluorine substitution, at least one hydrogen atom may be substituted by fluorine, but preferably all hydrogens are substituted by fluorine.

Here, in the present invention, alkenyl means a monovalent group having one or more double bonds (preferably one). Similarly, alkynyl refers to a monovalent group having one or more triple bonds (preferably one).

R^b1Preferably C_3-12Alkenyl or alkynyl (wherein CH in alkenyl and alkynyl₃-CH which may be substituted by phenyl and which is in alkenyl and alkynyl₂-may be substituted by at least one of-C (═ O) -, -O-or phenylene), C_3-5Thioalkyl, C_5-6A saturated heterocyclic ring.

R^b1Specific examples of (A) include-C.ident.C-CH₂-CH₂-CH₂-CH₃、-CH＝CH-C(＝O)-O-tBu、-CH＝CH-Ph、-S-CH(CH₃)₂、-CH＝CH-Ph-O-CH(CH₃)(CH₂CH₃) And piperidine. Here, tBu represents a tert-butyl group, and Ph represents a phenylene group or a phenyl group. Hereinafter, the same applies unless otherwise stated.

nb is preferably 0 or 1, and more preferably nb ═ 0. nb ═ 1 is also a preferred form.

R^b2Preferably C_1-4Alkyl in which all of the hydrogens of (A) are replaced with fluorine, more preferably C₁Or C₄Alkyl groups in which all of the hydrogens of the group (a) are substituted by fluorine. R^b2The alkyl group of (a) is preferably linear.

(B) Specific examples of the acid generator are as follows.

For example, the following specific example can be represented by formula (b). R^b1Is C₈Alkenyl, being-CH ═ CH-CH₂-CH₂-CH(CH₃)(CH₂CH₃) One of them is-CH₂-by substitution with phenylene, one-CH₂-is replaced by-O-.nb＝1。R^b2is-CF₃。

(B) The molecular weight of the acid generator is preferably 400 to 1,500, more preferably 400 to 700.

The content of the acid generator (B) is 0.1 to 10.0% by mass, more preferably 0.5 to 1.0% by mass, based on the total mass of the polymer (A).

(C) Dissolution rate modifier

The composition according to the invention comprises a dissolution rate modifier which is a compound in which two or more phenolic structures are linked by a hydrocarbyl group, the hydrocarbyl group optionally being substituted with an oxy group.

(C) The dissolution rate modifier has a function of modifying the solubility of the polymer in the developer. Although not being bound by theory, it is believed that due to the presence of (C) a dissolution rate modifier, a preferred pattern shape is formed by the following mechanism. (C) The dissolution rate modifier has a phenol structure and is highly soluble in an alkaline developer. During development, the developer first contacts the upper portion of the film. At this time, only the (C) dissolution rate modifier present in the vicinity of the film surface dissolves in the developer. As a result, the (C) dissolution rate modifier is lost in the vicinity of the film surface of the unexposed portion, the polymer is increased in molecular weight, and the solubility in an alkaline developer is lowered. On the other hand, the side surfaces of the formed resist pattern are easily dissolved, and the cross-sectional shape of the resist pattern becomes an inverted cone shape. By this mechanism, the dissolution rate modifier contributes to the formation of the reverse taper. As described above, (C) the dissolution rate modifier has a function of suppressing or promoting dissolution and adjusting the rate.

(C) The dissolution rate modifier is preferably a compound represented by formula (c).

In the formula (I), the compound is shown in the specification,

nc1 are each independently 1,2 or 3.

nc2 are each independently 0, 1,2 or 3.

R^c1Each independently is C_1-7The alkyl group of (a) is,

L^cis C_1-15A divalent alkylene group of (which may be substituted by an aryl group which may be substituted by a hydroxyl group, which may be substituted with L)^cOther substituents form a ring).

nc1 is preferably each independently 1 or 2, more preferably 1.

nc2 is preferably each independently 0, 2 or 3. In a preferred form, both nc2 are identical. nc2 of 0 is also a preferred form.

R^c1Preferably each independently is methyl, ethyl or cyclohexyl, more preferably methyl or cyclohexyl.

L^cPreferably C_2-12More preferably C_2-7A divalent alkylene group of (a). The aryl group which can substitute for the alkylene group may be a monovalent aryl group or a divalent arylene group. The aryl group is preferably a phenyl group or a phenylene group. The aryl groups may be substituted with hydroxyl groups, but preferably one aryl group is substituted with one or two hydroxyl groups, more preferably one hydroxyl group. L is^cThe alkylene group may be linear, branched, cyclic (preferably cyclohexylene) and may be any combination of these.

As with L^cExamples of other substituents forming a ring, for example, R may be mentioned^c1Or with OH and R^c1The bonded phenyl group forms an example of a ring. The following specific examples are given as examples of the latter ring formation.

L^cIs preferably-CR^c2R^c3-(wherein R is^c2Is hydrogen or methyl and R^c3Is aryl or aryl-substituted alkyl, wherein aryl may be substituted with hydroxy).

(C) Specific examples of the dissolution rate modifier are as follows.

For example, the following specific example can be represented by formula (c). Both nc1 are 1 and both nc2 are 2. R^c1Are both methyl groups. L is^cIs C₇A divalent alkylene group of, but one-CH₃Is replaced by a phenyl group, and the other tertiary carbon atom of the isopropyl group is partially replaced by a hydroxy-substituted phenyl group.

(C) The molecular weight of the dissolution rate modifier is preferably 90 to 1,500, more preferably 200 to 900.

The content of the dissolution rate modifier (C) is preferably 0.1 to 20% by mass, more preferably 2 to 5% by mass, based on the total mass of the polymer (A).

(D) Solvent(s)

The composition according to the invention comprises (D) a solvent. The solvent is not particularly limited as long as it can dissolve the components to be mixed. The solvent (D) is preferably water, a hydrocarbon solvent, an ether solvent, an ester solvent, an alcohol solvent, a ketone solvent, or a combination thereof.

Specific examples of the solvent include water, n-pentane, isopentane, n-hexane, isohexane, n-heptane, isoheptane, 2, 4-trimethylpentane, n-octane, isooctane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, isopropylbenzene, diethylbenzene, isobutylbenzene, triethylbenzene, diisopropylbenzene, n-pentylnaphthalene, trimethylbenzene, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n-nonanol, 2, 6-dimethylheptanol-4, n-decanol, sec-undecanol, trimethylnonanol, sec-tetradecanol, sec-heptadecanol, phenol, cyclohexanol, methylcyclohexanol, 3, 5-trimethylcyclohexanol, benzyl alcohol, benzylmethanol, diacetone alcohol, cresol, ethylene glycol, propylene glycol, 1, 3-butanediol, pentanediol-2, 4, 2-methylpentanediol-2, 4, hexanediol-2, 5, heptanediol-2, 4, 2-ethylhexanediol-1, 3, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerol, acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, diethyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, ethyl n-butyl ketone, methyl n-hexyl ketone, diisobutyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2, 4-pentanedione, acetonylacetone, diacetone alcohol, acetophenone, fenchyl ketone, diethyl ether, isopropyl ether, n-butyl ether (dibutyl ether, DBE), n-hexyl ether, 2-ethylhexyl ether, ethylene oxide, 1, 2-propylene oxide, dioxolane, 4-methyldioxolane, dioxane, dimethyldioxane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-n-hexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, ethylene glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol di-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriethylene glycol, tetraethylene glycol di-n-butyl ether, Propylene Glycol Monomethyl Ether (PGME), propylene glycol monoethyl ether, propylene glycol monopropyl ether, Propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, diethyl carbonate, methyl acetate, ethyl acetate, gamma-butyrolactone, gamma-valerolactone, n-propyl acetate, isopropyl acetate, n-butyl acetate (n-butyl acetate, nBA), isobutyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, ethyl acetoacetate, ethylene glycol monomethyl acetate, ethylene glycol monoethyl ether, diethylene glycol monomethyl acetate, Diethylene glycol acetic acid monoethyl ether, diethylene glycol acetic acid mono-N-butyl ether, propylene glycol acetic acid monomethyl ether, propylene glycol acetic acid monoethyl ether, propylene glycol acetic acid monopropyl ether, propylene glycol acetic acid monobutyl ether, dipropylene glycol acetic acid monomethyl ether, dipropylene glycol acetic acid monoethyl ether, ethylene glycol diacetate, methoxy triethylene glycol acetate, ethyl propionate, N-butyl propionate, isoamyl propionate, diethyl oxalate, di-N-butyl oxalate, methyl lactate, Ethyl Lactate (EL), gamma-butyrolactone, N-butyl lactate, N-pentyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate, propylene glycol 1-monomethyl ether 2-acetate (PGMEA), propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, N-methylformamide, N-dimethylformamide, N-diethylformamide, Acetamide, N-methylacetamide, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone, dimethyl sulfide, diethyl sulfide, thiophene, tetrahydrothiophene, dimethyl sulfoxide, sulfolane and 1, 3-propanesultone. These solvents may be used alone or in combination of two or more.

The solvent (D) preferably contains a low boiling point solvent, and more preferably contains 60% or more of the low boiling point solvent based on the total mass of the solvent (D).

In the present invention, the low boiling point solvent is a solvent having a boiling point of 80 to 140 ℃, more preferably 110 to 130 ℃. The boiling point is measured at atmospheric pressure. As the low boiling point solvent, PGME and nBA can be cited.

(D) The solvent is preferably PGME, EL, PGMEA, nBA, DBE or any mixture thereof. When the two solvents are mixed, the mass ratio of the first solvent to the second solvent is preferably 95:5 to 5:95 (more preferably 90:10 to 10: 90). (D) The solvent is preferably a mixture of PGME and EL.

It is believed that the composition according to the present invention contributes to the formation of the reverse conical shape, since the (D) solvent contains at least one low boiling point solvent. Without being bound by theory, it is believed that the following mechanism. Since the (D) solvent contains a low boiling point solvent, the (D) solvent is more volatilized when applied to a substrate and heated according to the present invention, and the content of the solvent in the formed film is reduced. That is, it becomes a high-density film. Since the density of the film is high, the density of acid generated from the (B) acid generator in the exposed portion increases, and the frequency of acid diffusion increases. As described above, the influence of the diffused acid is suppressed due to the higher molecular weight in the vicinity of the surface, but is easily influenced by the diffused acid at the side and lower portions of the pattern. This facilitates the formation of the reverse tapered shape. Further, in the case where the basic compound of (E) is contained, as described later, the effect of suppressing the diffusion of the acid is provided in the upper portion of the unexposed portion, and the effect of suppressing the diffusion in the lower portion is less, so that the reverse tapered shape is further easily formed.

The (D) solvent is also a form free of water due to the relationship with other layers and films. For example, the amount of water in the entire (D) solvent is preferably 0.1% by mass or less, more preferably 0.01% by mass or less, and still more preferably 0.001% by mass or less.

The content of the (D) solvent is 40 to 90% by mass, more preferably 30 to 50% by mass, based on the total mass of the composition. By increasing or decreasing the amount of solvent in the entire composition, the film thickness after film formation can be controlled.

(E) Basic compound

The compositions according to the invention may also contain (E) basic compounds.

(E) The basic compound has an effect of suppressing diffusion of an acid generated at an exposed portion. Therefore, in the present invention, (E) the basic compound is considered to function to contribute to the formation of the reverse tapered shape. While not being bound by theory, the mechanism is believed to be as follows. When the composition according to the present invention is applied to a substrate to form a film, (E) the basic compound is uniformly present in the film. Thereafter, when heated, a part of (E) the basic compound present above the film is volatilized in the atmosphere together with the solvent, and the nonvolatile part also moves upward. As a result, the distribution of the (E) basic compound in the film is not uniform, and more distribution is present in the upper part and less distribution is present in the lower part. An acid is released from the acid generator by exposure, and when such an acid diffuses to an unexposed portion by heating or the like after exposure, a neutralization reaction occurs with such (E) basic compound, whereby the acid is transferred to the unexposed portion. At this time, since the distribution of the (E) basic compound in the film is not uniform, the effect of suppressing acid diffusion above the film in the unexposed portion is high, but the effect of suppressing acid diffusion below the film is low. That is, the acid distribution in the lower portion is higher than in the upper portion. This contributes to the formation of a reverse taper upon development with an alkaline developer.

In addition to the above effects, the basic compound also has an effect of suppressing inactivation of an acid on the surface of the resist film due to an amine component contained in the air.

(E) The basic compound is preferably selected from ammonia, C_1-16Aliphatic primary amine, C_2-32Aliphatic Secondary amine, C_3-48Aliphatic tertiary amine, C_6-30Aromatic amine, and C_5-30Heterocyclic amines and derivatives thereof.

Specific examples of the basic compound include ammonia, ethylamine, n-octylamine, ethylenediamine, triethylamine, triethanolamine, tripropylamine, tributylamine, triisopropanolamine, diethylamine, tris [2- (2-methoxyethoxy) ethyl ] amine, 1, 8-diazabicyclo [5.4.0] undec-7-ene, 1, 5-diazabicyclo [4.3.0] nonen-5-ene, 7-methyl-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene, 1,5, 7-triazabicyclo [4.4.0] dec-5-ene.

(E) The molecular weight of the basic compound is preferably 17 to 500, more preferably 100 to 350.

The content of the basic compound (E) is preferably 0 to 1.0% by mass, more preferably 0.05 to 0.3% by mass, based on the total mass of the polymer (A). It is also a preferable form that the composition does not contain (E) a basic compound in view of the storage stability of the composition.

(F) Plasticizer

The compositions according to the invention may also contain (F) a plasticizer. By adding the plasticizer, generation of cracks in the resist pattern can be suppressed.

Examples of the plasticizer include alkali-soluble vinyl polymers and vinyl polymers containing acid dissociation groups. More specifically, for example, polyvinyl chloride, polystyrene, polyhydroxystyrene, polyvinyl acetate, polyvinyl benzoate, polyvinyl ether, polyvinyl butyral, polyvinyl alcohol, polyether ester, polyvinyl pyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylate, polyimide maleate, polyacrylamide, polyacrylonitrile, polyvinyl phenol, phenol resin and copolymers thereof, and polyvinyl ether, polyvinyl butyral and polyether ester are more preferable.

(F) The plasticizer preferably contains a structural unit represented by the formula (f-1) and/or a structural unit represented by the formula (f-2).

The formula (f-1) is as follows.

In the formula (I), the compound is shown in the specification,

R^f1each independently is hydrogen or C_1-5And is an alkyl group of

R^f2Each independently is hydrogen or C_1-5Alkyl group of (1).

R^f1Preferably each independently is hydrogen or methyl.

R^f2Preferably each independently is hydrogen or methyl.

More preferably, two R^f1And two R^f2One of which is methyl and the remaining three are hydrogen.

The formula (f-2) is as follows.

In the formula (I), the compound is shown in the specification,

R^f3each independently is hydrogen or C_1-5Alkyl of R^f4Is hydrogen or C_1-5And is an alkyl group of

R^f5Is C_1-5Alkyl group of (1).

R^f3Preferably each independently is hydrogen or methyl, more preferably both are hydrogen.

R^f4Preferably hydrogen or methyl, more preferably hydrogen.

R^f5Preferably methyl or ethyl, more preferably methyl.

(F) Specific examples of the plasticizer are as follows.

PO: propylene oxide

(F) The mass average molecular weight of the plasticizer is preferably 1,000 to 50,000, more preferably 1,500 to 30,000, still more preferably 2,000 to 21,000, and still more preferably 3,000 to 21,000.

(F) The content of the plasticizer is preferably 0 to 30% by mass, more preferably 1 to 10% by mass, based on the total mass of the polymer (a). The absence of a plasticizer is also a preferred form of the invention.

(G) Additive agent

The composition according to the present invention may contain (G) an additive other than (a) to (F).

(G) The additive is not particularly limited, and is preferably at least one selected from the group consisting of a surfactant, an acid, and a substrate adhesion enhancer.

The content of the additive (G) is 0 to 20% by mass, more preferably 0 to 11% by mass, based on the total mass of the polymer (A). (G) The absence of additives (0 mass%) is also a preferred example of the composition according to the invention.

The coating property can be improved by containing a surfactant. As the surfactant usable in the present invention, there can be cited (I) an anionic surfactant, (II) a cationic surfactant or (III) a nonionic surfactant, and specifically, preferred are (I) an alkylsulfonate, an alkylbenzenesulfonic acid and an alkylbenzenesulfonic acid salt, (II) a monthly pyridinium chloride month and a monthly methylchloride month, and (III) a polyoxyethylene octyl ether, a polyoxyethylene monthly ether and a polyoxyethylene acetylene glycol ether.

These surfactants may be used singly or in combination, and the content thereof is preferably 2% by mass or less, more preferably 1% by mass or less, based on the total mass of the polymer (a).

The acid may be used to adjust the pH of the composition and to increase the solubility of the additive components. The acid used is not particularly limited, for example, formic acid, acetic acid, propionic acid, benzoic acid, phthalic acid, salicylic acid, lactic acid, malic acid, citric acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, tricarballylic acid, adipic acid, and combinations thereof. The acid content is preferably 0.005 to 0.1 mass% (50 to 1,000ppm) based on the total mass of the composition.

By using the substrate adhesion enhancer, pattern peeling due to stress applied during film formation can be prevented. The substrate adhesion enhancer is preferably an imidazole compound or a silane coupling agent, and of the imidazoles, 2-hydroxybenzimidazole, 2-hydroxyethylbenzimidazole, benzimidazole, 2-hydroxyimidazole, imidazole, 2-mercaptoimidazole, and 2-aminoimidazole are preferable, and 2-hydroxybenzimidazole, benzimidazole, 2-hydroxyimidazole, and imidazole are more preferable. The content of the substrate adhesion enhancer is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, even more preferably 0.01 to 5% by mass, and even more preferably 0.1 to 3% by mass, based on the total mass of the polymer (a).

< method for producing resist Pattern >

The method for manufacturing a resist pattern according to the present invention includes:

(1) applying a composition according to the invention on a substrate;

(2) heating the composition to form a resist layer;

(3) exposing the resist layer;

(4) heating the resist layer after exposure; and

(5) and developing the resist layer.

For clarity, numerals in parentheses indicate order. For example, step (1) is performed before step (2).

One embodiment of the production method of the present invention will be described below.

The composition according to the invention is applied over a substrate (e.g. a silicon/silicon dioxide coated substrate, a silicon nitride substrate, a silicon wafer substrate, a glass substrate, an ITO substrate, etc.) by a suitable method. Here, in the present invention, the upper portion includes a case where the upper portion is directly formed and a case where the upper portion is formed with another layer interposed therebetween. For example, a planarizing film or a resist underlayer film may be formed directly above a substrate, and the composition according to the present invention may be applied directly above the planarizing film or the resist underlayer film. The coating method is not particularly limited, and for example, a coating method by a spinner and a coater. After coating, a resist layer is formed by heating. (2) The heating of (2) is performed by a hot plate, for example. The heating temperature is preferably 60 to 140 ℃, and more preferably 90 to 110 ℃. The temperature here is the heating atmosphere, for example the heating surface temperature of the heating plate. The heating time is preferably 30 to 900 seconds, and more preferably 60 to 300 seconds. The heating is preferably performed in an air or nitrogen atmosphere.

The film thickness of the resist layer is selected according to the purpose, but if the composition according to the present invention is used, a pattern having a better shape can be formed in the case of forming a coating film having a thick film thickness. Therefore, the thickness of the resist film is preferably large, for example, preferably 1 μm or more, and more preferably 5 μm or more.

The resist layer is exposed through a predetermined mask. The wavelength of the light used for exposure is not particularly limited, but exposure is preferably performed with light having a wavelength of 190 to 440 nm. Specifically, KrF excimer laser (wavelength 248nm), ArF excimer laser (wavelength 193nm), i-line (wavelength 365nm), h-line (wavelength 405nm), g-line (wavelength 436nm), and the like can be used. The wavelength is more preferably 240 to 440nm, still more preferably 360 to 440nm, and still more preferably 365 nm. These wavelengths are allowed to be within a range of ± 1%.

After exposure, post-exposure heating (hereinafter, may be referred to as PEB) is performed. (4) The heating of (2) is performed by a hot plate, for example. The temperature of heating after exposure is preferably 80-160 ℃, more preferably 105-115 ℃, and the heating time is 30-600 seconds, preferably 60-200 seconds. The heating is preferably performed in an air or nitrogen atmosphere.

After PEB, development was performed using a developer. As the developing method, a method conventionally used for developing a photoresist, such as a paddle developing method, a dip developing method, and a shaking dip developing method, can be used. The developer may be an aqueous solution containing an inorganic base such as sodium hydroxide, potassium hydroxide, sodium carbonate, or sodium silicate, an organic amine such as ammonia, ethylamine, propylamine, diethylamine, diethylaminoethanol, or triethylamine, or a quaternary ammonium salt such as tetramethylammonium hydroxide (TMAH), and preferably a 2.38 mass% aqueous solution of TMAH. A surfactant may also be added to the developer. The temperature of the developing solution is preferably 5-50 ℃, more preferably 25-40 ℃, and the developing time is preferably 10-300 seconds, more preferably 30-60 seconds. After development, the plate may be washed or rinsed with water, if necessary. Since a positive resist composition is used, the exposed portion is removed by development to form a resist pattern. The resist pattern can also be further refined by using, for example, a shrink material.

Since the unexposed portion is hardly dissolved in the developer by development, the thickness of the formed resist pattern and the resist layer can be considered to be the same.

By using the composition of the present invention, a resist pattern having an inverted conical shape can be formed. Here, in the present invention, the reverse tapered shape means that, when the resist pattern 12 is formed on the substrate 11 as shown in the cross-sectional view of fig. 1a, the angle formed by the straight line (taper line) connecting the opening point (boundary between the resist surface and the resist pattern side surface) 13 and the bottom point (boundary between the substrate surface and the resist pattern side surface) 14 with the substrate surface is greater than 90 degrees, and the resist pattern does not substantially protrude outward than the taper line, that is, the resist pattern does not substantially swell. This angle is referred to herein as the cone angle 15. Such a resist pattern is referred to as an inverted cone-shaped resist pattern 12. In the present invention, the reverse tapered shape refers not only to a reverse truncated cone shape (reversed truncated cone), but also includes a case where the line width of the surface portion is wider than the line width in the vicinity of the substrate in the line pattern.

In the reverse-tapered resist pattern according to the present invention, as shown in the cross-sectional view of fig. 1 (B), there is also included a case where the resist pattern is recessed inward from a straight line (taper line 24) connecting the opening point 2 and the bottom point 23, that is, the resist pattern is thin. The cone angle here is the cone angle 25. Such a resist pattern is referred to as an overhang-shaped resist pattern 21. A straight line parallel to the substrate surface is drawn from the substrate at a height of half the length 27 of the film thickness 26 of the resist pattern, and the distance between the intersection with the resist pattern and the intersection with the taper line on this straight line is the bite width 28. Similarly, on this straight line, the distance between the intersection with the resist pattern and the intersection with a straight line drawn perpendicular to the substrate from the opening point is referred to as the taper width 29. When the biting width/taper width is larger than 0, (B) in FIG. 1, and when it is 0, (A) in FIG. 1.

The case of the overhang shape is preferable because the mold release liquid is easily entered when the resist is peeled after metal evaporation.

As a modification of the overhang shape, as shown in (C) of fig. 1, a case where the end of the resist pattern 31 is rounded may be considered. In this case, the opening point 32 is a point where the resist pattern is separated from a plane of the resist surface parallel to the bottom surface, assuming that the boundary between the resist surface and the side surface of the resist pattern is the plane. The bottom point 33 is a boundary between the substrate surface and the resist pattern side. The straight line connecting the opening point 32 and the bottom point 33 is a cone line 34, here the cone angle 35.

The area of the non-resist pattern portion inside the taper line is S_in36 area of the non-resist pattern portion outside the taper line is S_out37. In many cases, the sum of the areas is used.

S_out/(S_in+S_out) Preferably 0 to 0.45, more preferably 0 to 0.1, further preferably 0 to 0.05, and further preferably 0 to 0.01. S_out/(S_in+S_out) The small shape is advantageous because the resist sidewall is easily penetrated by the stripper even if the metal is thickly evaporated on the resist pattern. The T-type resist pattern described in patent document 3 has S of about 0.5_out/(S_in+S_out)。

(S_in-S_out)/(S_in+S_out) Preferably 0 to 1, more preferably 0.55 to 1, further preferably 0.9 to 1, and further preferably 0.99 to 1.0<(S_in-S_out)/(S_in+S_out) Are also preferred forms of the invention. When (S)_in-S_out)/(S_in+S_out) When the thickness is large, the resist pattern as a whole has a shape recessed from the taper line, and even if a thick metal is deposited on the resist pattern, the stripping liquid easily penetrates into the resist sidewall, which is advantageous.

In the case of the shapes corresponding to (A) and (B) of FIG. 1, both are S_out/(S_in+S_out) 0 and both are (S)_in-S_out)/(S_in+S_out)＝1。

It is known that when a resist pattern is formed using a chemical amplification resist, the shape of the resist pattern changes when the set time (PED: Post Exposure Delay) from Exposure to PEB becomes long. This phenomenon is considered to be caused by the fact that an acid generated in an exposed portion of the resist is neutralized by a basic compound (e.g., an amine component) in the air, and the solubility of the surface of the resist film in the exposed portion is lowered. The top of the resist film is susceptible to such effects and the top exposed portion may partially remain undeveloped.

The composition according to the invention is less susceptible to the above-mentioned shape changes than conventionally known compositions. That is, it has properties against environmental influences.

Further, the metal pattern may be manufactured by a method including the following steps.

(6) Evaporating metal on the substrate by taking the resist pattern as a mask;

(7) the resist pattern is removed with a stripping liquid.

Using the resist pattern as a mask, a metal such as gold, copper, or the like (which may be a metal oxide or the like) is evaporated over the substrate. In addition to evaporation, sputtering may be used.

Thereafter, a resist pattern may be formed by removing the resist pattern together with the metal formed thereon using a stripping liquid. The stripping solution is not particularly limited as long as it is used as a resist stripping solution, and for example, N-methylpyrrolidone (NMP), acetone, an alkaline solution, or the like can be used. Since the resist pattern of the present invention has a reverse tapered shape, the metal on the resist pattern and the metal formed at the portion where the resist pattern is not formed are separated from each other, and thus can be easily stripped. The thickness of the metal pattern to be formed can be increased, and the metal pattern can be formed to a thickness of preferably 0.01 to 40 μm, more preferably 1 to 5 μm.

As another embodiment of the present invention, various substrates as a base may be patterned using the resist pattern formed up to step (5) as a mask. The substrate may be directly processed using the resist pattern as a mask, or may be processed via an intermediate layer. For example, the resist underlayer film may be patterned using the resist pattern as a mask, and the substrate may be patterned using the resist underlayer film as a mask. The processing may be performed by a known method, and a dry etching method, a wet etching method, an ion implantation method, a metal plating method, or the like may be used. Electrodes and the like may be disposed on the patterned substrate.

The substrate is then further processed, as necessary, to form devices. Known methods may be applied to these further treatments. After forming the device, the substrate is cut into chips, connected to a lead frame, and encapsulated with resin, if necessary. In the present invention, the packaged product is referred to as a device. Examples of the device include a semiconductor device, a liquid crystal display element, an organic EL display element, a plasma display element, and a solar cell element. The device is preferably a semiconductor.

[ examples ]

The invention will be described with reference to various embodiments. Aspects of the present invention are not limited to these examples.

Example 1: preparation of composition 1

To 170 parts by mass of a mixed solvent of PGME: EL of 85:15 (mass ratio) were added 50 parts by mass of P1 described below as a polymer P and 150 parts by mass of Q described below as a polymer Q. To this, 1.6 mass% of the following B1 as an acid generator, 2.5 mass% of the following C1 as a dissolution rate modifier, 0.1 mass% of tris [2- (2-methoxyethoxy) ethyl ] amine as a basic compound, 5.0 mass% of the following F1 as a plasticizer, and 0.1 mass% of KF-53 (shin-Etsu chemical Co., Ltd.) as a surfactant were added, respectively, based on the total mass of the whole composition. Stirred at room temperature for 5 hours. It was visually confirmed that the additive was dissolved. The mixture was filtered through a 1.0 μm filter. Thus, composition 1 was obtained. The viscosity of composition 1 measured by the Canon Fenske method at 25 ℃ was 600 cP.

(P1) hydroxystyrene-styrene-t-butyl acrylate copolymer, Toho chemical Co., Ltd., molar ratio of 60:20:20, Mw of about 12,000

(Q1) (Q-1a) (Q-1b) (Q-1c) (Q-1d) 60:40:0: 0:0 Polymer, Sumitomo bakelite, Mw about 5,000

(B1) NIT, Heley

(C1) TPPA-MF, national chemical industries, Inc

(F1) Lutonal, Basff

Examples 2 to 10 and comparative examples 1 to 3: preparation of compositions 2 to 10 and comparative compositions 1 to 2

Preparation was carried out similarly to composition 1 except that the polymer and dissolution rate modifier were changed as described in table 1, obtaining compositions 2 to 10, and comparative compositions 1 to 3.

TABLE 1

Resist pattern formation

Using the composition obtained above, the following operations were performed to obtain a resist pattern.

Each composition was dropped on a 6-inch silicon wafer using lithotrac (litho Tech japan) and spin-coated to form a resist layer. The wafer having the resist layer formed thereon was baked at 100 ℃ for 180 seconds using a hot plate. After baking, the film thickness of the resist layer was measured using an optical interference type film thickness measuring apparatus Lambda Ace VM-12010 (SCREEN). The film thickness was measured at 8 points other than the center of the wafer, and the average value thereof was used. The film thickness obtained is shown in Table 1.

Then, it was exposed with i-line (365nm) using a Suss Aligner (Suss Micro Tech). After exposure, the wafer was exposed on a hot plate at 120 ℃ for 120 seconds and then heated. This was subjected to spin immersion development with 2.38% aqueous TMAH for 60 seconds. Thus, a resist pattern having a line of 10 μm and a space (groove) of 10 μm (line: space: 1) was obtained.

In the case of example 1, the exposure energy (mJ/cm) at a mask size and a pattern size of 1:1²) Is 120mJ/cm²。

Evaluation of taper Angle

The cross-sectional shape of the resulting resist pattern was observed using a scanning electron microscope SU8230 (hitachi technologies), and the cone angle defined above was measured. The cross-sectional shape of the resist pattern formed in example composition 5 is shown in fig. 2 (a). Fig. 2 (B) schematically shows a sectional view thereof. The results obtained are shown in table 1.

In the cross-sectional shape of the resist pattern formed in example composition 5, S was as defined above_out/(S_in+S_out)＝0，(S_in-S_out)/(S_in+S_out)＝1。

Evaluation of crack resistance

A composition containing no plasticizer, 2.5 mass%, 7.5 mass%, and 10.0 mass% of a plasticizer in the composition of example composition 1 (which contained 5 mass% of a plasticizer) was prepared, a resist pattern was formed in the same manner as described above, and gold was vapor-deposited using a sputtering apparatus. Thereafter, the presence or absence of cracks was visually confirmed by an optical microscope. A small amount of cracks were observed in the case where the plasticizer was not contained, but cracks were reduced in the case where the plasticizer was contained in an amount of 2.5 mass% as compared with the case where the plasticizer was not contained. In the compositions containing 5 mass%, 7.5 mass%, and 10.0 mass% of the plasticizer, no cracks were observed at all.

Description of the reference numerals

11. Substrate

12. Reverse tapered resist pattern

13. Opening point

14. Bottom point

15. Taper angle

21. Resist pattern of overhang shape

22. Opening point

23. Bottom point

24. Taper wire

25. Taper angle

26. Film thickness of resist pattern

27. Half length of resist pattern film thickness

28. Bite width

29. Taper width

31. Resist pattern

32. Opening point

33. Bottom point

34. Taper wire

35. Taper angle

36.S_in

37.S_out

51. Substrate

52. And (3) resist pattern.