WO2014030687A1

WO2014030687A1 - A resist stripping solution and a resist strip process

Info

Publication number: WO2014030687A1
Application number: PCT/JP2013/072340
Authority: WO
Inventors: Tetsuya Kamimura
Original assignee: Fujifilm Corporation
Priority date: 2012-08-22
Filing date: 2013-08-15
Publication date: 2014-02-27
Also published as: TW201415177A; TWI595331B; JP2014041260A; JP6144468B2

Abstract

A resist stripping solution for stripping a resist on a substrate, being prepared in a non-aqueous condition, the resist stripping solution comprising: a first water-soluble organic solvent occupying 80 to 90% by mass of the resist stripping solution; a second water-soluble organic solvent occupying 1 to 15% by mass of the resist stripping solution; and an amino alcohol compound represented occupying 1 to 15% by mass of the resist stripping solution.

Description

DESCRIPTION

A RESIST STRIPPING SOLUTION AND A RESIST STRIP PROCESS TECHNICAL FIELD

{0001 }

The present invention relates to a resist stripping solution and a resist strip process. BACKGROUND ART

{0002}

In the process of producing a semiconductor device, a liquid crystal display, and the like, it includes a step of removing a resist from the top of the semiconductor substrate. In the process, various methods are selectively applied for properly removing the resist, depending on the properties and the processing shape of the resist. Examples of a resist removal process include a method for removing a resist by ashing it with active plasma such as oxygen or ozone, and a method for removing a resist by oxidizing, water-solubilizing or dissolving it with a chemical liquid.

As to the technique of removing a resist with the above-described chemical liquid, examples include a method of using hydrogen peroxide, sulfuric acid or the like, and a method of using both amines and an organic solvent. In connection with the material latter above, there are Patent Literatures 1 to 4, which disclose a remover using both amines and an organic solvent.

CITATION LIST

Patent Literatures

{0003}

Patent Literature 1 : JP-A-2000-39727 ("JP-A" means unexamined published Japanese patent application)

Patent Literature 2: JP-A-2000-75506

Patent Literature 3 : JP-A-2004-66155

Patent Literature 4: JP-A-2004- 177669 DISCLOSURE OF INVENTION

TECHNICAL PROBLEM

{0004}

The resist for use in the semiconductor production varies in kind, and the compounding design is needed as to a stripping solution to be suitable for each resist. Referring to the technical content described in the above-described Patent Literatures, there is no disclosure consciously to reveal the relationship between a stripping solution and the kind of resist which can be a target of removal. Among these, in the present invention, focusing attention on the removal of not only a negative-type resist but also a positive-type resist, the inventors have pursued research and development on a stripping solution that is favorably responsible to this demand. For the technique described in the above-described Patent Literature 4, a novorak resin (a positive-type resist) is exemplified as a stripping target. It is however not clear, in the patent literature, as to details of the resin and the compatibility with a chemical liquid, and the like.

According to the investigation by the present inventors, it has been understood that the presently-aimed target levels can not be achieved by the chemical liquid having the formulation described in the above-described Patent Literature 4 (see the comparative examples described below). Further, the present inventors have searched formulation of the resist stripping solution which enables a low-temperature processing at near room temperature from the viewpoints of reduction in cost and convenience of processing, or the like.

{0005}

In view of the above, the present invention contemplates to the provision of a resist stripping solution and a resist strip process, each of which is capable of favorably responding to the stripping and removal of not only a negative-type resist but also a positive-type resist such as a novorak resin, and effectively strips, without damaging a substrate material, the resist existing thereon.

SOLUTION TO PROBLEM

{0006} { 1 } A resist stripping solution for stripping a resist on a substrate, being prepared in a non-aqueous condition, the resist stripping solution comprising:

a first water-soluble organic solvent containing at least one compound selected from the group consisting of a compound represented by formula (1-1), a compound represented by formula (1-2) and a compound represented by formula (1-3), the first water-soluble organic solvent occupying 80 to 90% by mass of the resist stripping solution;

a second water-soluble organic solvent represented by formula (II) , the second water-soluble organic solvent occupying 1 to 15% by mass of the resist stripping solution; and

an amino alcohol compound represented by formula (III), an amino alcohol compound occupying 1 to 15% by mass of the resist stripping solution;

(1-1) (1-2) (1-3) (II) OH) wherein, in the formulae, R¹ to R⁵ respectively represent a hydrogen atom or an alkyl group; R⁶ and R⁷ respectively represent a hydrogen atom, an alkyl group or an alkoxy group; R⁹ represents a hydrogen atom or an alkyl group; R¹⁰ to R¹² respectively represent a hydrogen atom, an alkyl group or a hydroxyalkyl group; however, at least one of R¹⁰ to R¹² represent a hydroxyalkyl group; R⁸ represents an alkylene group; n represents an integer of 1 to 4.

{2} The resist stripping solution according to { 1 }, wherein the first water-soluble organic solvent is a solvent selected from the group consisting of dimethyl sulfoxide (DMSO), dimethylacetamide (DMAc), dimethylformamide (DMF) methylethyl ketone (MEK), methylisobutyl ketone (MIK), cyclohexanone (CHN), cyclopentanone (CPN), methylpropyl ketone (MPK), and 2-hydroxyisobutyric acid methyl (HBM).

{3} The resist stripping solution according to { 1 } or {2}, wherein the second water-soluble organic solvent is a solvent selected from the group consisting of ethylene glycol monomethyl ether (EGME), ethylene glycol monoethyl ether (EGEE), ethylene glycol monopropyl ether (EGPE), ethylene glycol monobutyl ether (EGBE), propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether (PGEE), propylene glycol monopropyl ether (PGPE), propylene glycol monobutyl ether (PGBE), diethylene glycol monomethyl ether (DEGME), diethylene glycol monoethyl ether (DEGEE), diethylene glycol monopropyl ether (DEGPE), diethylene glycol monobutyl ether (DEGBE), dipropylene glycol monomethyl ether (DPGME), dipropylene glycol monoethyl ether (DPGEE), dipropylene glycol monopropyl ether (DPGPE),

dipropylene glycol monobutyl ether (DPGBE), triethylene glycol monomethyl ether (TEGME), triethylene glycol monoethyl ether (TEGEE), triethylene glycol monopropyl ether (TEGPE), triethylene glycol monobutyl ether (TEGBE), tripropylene glycol monomethyl ether (TPGME), tripropylene glycol monoethyl ether (TPGEE), tripropylene glycol monopropyl ether (TPGPE), and tripropylene glycol monobutyl ether (TPGBE).

{4} The resist stripping solution according to any one of { 1 } to {3}, wherein the amino alcohol compound is a compound selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), N-methylethanolamine (NMEA), Ν,Ν-dimethylethanolamine (DMMEA), N-methyldiethanolamine (DEMEA), aminoethylethanolamine (AEMEA), N,N-dimethylaminoethylethanolamine

(DMAEMEA), aminoethoxyethanol (AEE), N,N-dimethylaminoethoxyethanol

(DMAEE), and propanolamine (MP A).

{5} The resist stripping solution according to any one of { 1 } to {4}, wherein each of from 1 to 10 parts by mass of the second water-soluble organic solvent and from 1 to 10 parts by mass of an organic amine compound is compounded with respect to 100 parts by mass of the first water-soluble organic solvent.

{6} The resist stripping solution according to any one of { 1 } to {5}, wherein the resist to be removed is a positive-type resist.

{7} The resist stripping solution according to any one of { 1 } to {6}, wherein the resist is a positive-type resist comprising at least one of a novorak resin and a polyhydroxystyrene resin.

{8} The resist stripping solution according to any one of { 1 } to {7}, wherein the resist is applied to a resist stripping at the temperature of equal to or less than 35°C. {9} A resist strip process comprising the steps of preparing a resist stripping solution and applying the resist stripping solution onto a semiconductor substrate so as to strip a resist on the semiconductor substrate;

the resist stripping solution comprising:

a first water-soluble organic solvent containing at least one compound selected from the group consisting of a compound represented by formula (I-l), a compound represented by formula (1-2) and a compound represented by formula (1-3), the first water-soluble organic solvent occupying 80 to 90% by mass of the resist stripping solution;

(1-1 ) 0-2) (1-3) (H) (III) wherein, in the formulae, R¹ to R⁵ respectively represent a hydrogen atom or an alkyl group; R⁶ and R⁷ respectively represent a hydrogen atom, an alkyl group or an alkoxy group; R⁹ represents a hydrogen atom or an alkyl group; R¹⁰ to R¹² respectively represent a hydrogen atom, an alkyl group or a hydroxyalkyl group; however, at least one of R to R represent a hydroxyalkyl group; R represents an alkylene group; n represents an integer of 1 to 4.

{ 10} The resist strip process according to {9} , wherein the resist to be removed is a positive-type resist.

{11 } The resist strip process according to {9} or { 10}, wherein the resist is a positive-type resist comprising at least one of a novorak resin and a polyhydroxystyrene resin.

{ 12} The resist strip process according to any one of {9} to { 1 1 }, wherein the thickness of a resist layer is from 5 to 500μηι.

{ 13} The resist strip process according to any one of {9} to { 12}, wherein

application of the resist stripping solution onto the semiconductor substrate is performed at the temperature of equal to or less than 35°C.

{ 14} A method for producing a semiconductor substrate product comprising stripping a resist on a semiconductor substrate in accordance with a resist strip process according to any one of {9} to { 13}, and then producing the semiconductor substrate product using the processed semiconductor substrate.

In the present specification, the term "having" is to be construed in the open- ended meaning as well as the term "comprising" or "containing." Further, the term

"providing" or "preparing" broadly means, without any limitation in the inventive scope, to make the object ready to use, e.g., not only by synthesizing or producing the material, but also merely by purchasing it.

ADVANTAGEOUS EFFECTS OF INVENTION

{0007}

A resist stripping solution and a resist strip process of the present invention are capable of favorably responding to the stripping and removal of not only a negative- type resist but also a positive-type resist such as a novorak resin, and effectively stripping, without damaging a substrate material, the resist existing thereon. Further, they have the advantage of being able to perform a resist strip process at a low

temperature of near room temperature, if needed.

Other and further features and advantages of the invention will appear more fully from the following description. MODE FOR CARRYING OUT THE INVENTION

{0008}

The resist stripping solution of the present invention incorporates a specific amount of a first water-soluble organic solvent, a specific amount of a second water- soluble organic solvent and a specific amount of an amino alcohol compound.

Hereinafter, the present invention is described in detail, based on a preferable example thereof. {0009}

(First water-soluble organic solvent)

The first water-soluble organic solvent includes a compound selected from the group consisting of a compound represented by formula (1-1), a compound represented by formula (1-2) and a compound represented by formula (1-3).

{0010}

In the formulae, R¹ to R⁵ respectively represent a hydrogen atom or an alkyl group. R⁶ and R⁷ represent a hydrogen atom, an alkyl group or an alkoxy group. The

1 7

above alkyl group of R to R is respectively preferably having 1 to 8 carbon atom(s), an alkyl group having 1 to 4 carbon atom(s) is more preferable. The above alkoxy group

7

of R and R is respectively preferably having 1 to 8 carbon atom(s), an alkoxy group having 1 to 4 carbon atom(s) is more preferable. The alkyl group, although it may be chain-like (branched or straight chain) or cyclic, is preferably chain-like. The alkyl group may have a substituent, examples of the substituents include a methyl group, an ethyl group, a propyl group, a butyl group (including a tert-butyl group), or hydroxy group. As for R¹ to R⁷, those lying next to each other may combine together to form a ring.

{0011 }

The first water-soluble organic solvent is preferably a solvent selected from the group consisting of dimethyl sulfoxide (DMSO), dimethylacetamide (DMAc), dimethylformamide (DMF) methylethyl ketone (MEK), methylisobutyl ketone (MIK), cyclohexanone (CHN), cyclopentanone (CPN), methylpropyl ketone (MPK), and 2- hydroxyisobutyric acid methyl (HBM).

{0012}

The first water-soluble organic solvent is incorporated in the stripping solution in an amount of at least 80% by mass, preferably at least 81% by mass. It is incorporated in the upper limit of equal to or less than 90% by mass, preferably equal to or less than 89% by mass. Incorporation of the first water-soluble organic solvent in the lower limit or above preferably makes it possible to more efficiently dissolve a resist stripper (Hansen solubility Parameter can be maintained to a desirable range). In the present invention, especially the lower limit of the first water-soluble organic solvent, that is to say, the water-soluble organic solvent-based solvent has an important technical implication. Setting to the upper limit or below preferably makes it possible to efficiently dissolve the resist stripper (Hansen solubility Parameter due to the second solvent can be adjusted to a desirable range).

The first water-soluble organic solvent can be contained in the solution as one compound, two or more compounds, which are selected from the above exemplified compounds.

{0013}

(Second water-soluble organic solvent)

The second water-soluble organic solvent includes a compound represented by formula (II).

(ID HO -(-R⁸0-)-n-OR⁹

{0014}

In the formula, R⁹ represents a hydrogen atom or an alkyl group. The preferable range of an alkyl group has the same meaning as that of R^l to R⁵.

Specifically, the alkyl group of R⁹ is preferably having 1 to 8 carbon atom(s), more preferably having 1 to 4 carbon atom(s). The alkyl group of R⁹ can have a linking group in the chain, within the extent of the effect of the invention being expected.

Preferable linking groups include O, S, NR^N, or the like. Here, R^N is a hydrogen atom or alkyl group of having 1 to 6 carbon atoms, preferably having 1 to 3 carbon atoms.

R⁸ represents an alkylene group. As an alkylene group, an alkylene group having 1 to 4 carbon atoms is preferable, an alkylene group having 2 to 4 carbon atoms is more preferable, an alkylene group having 2 to 3 carbon atoms is particularly preferable. The alkylene group of R⁸ can have a linking group in the chain, within the extent of the effect of the invention being expected. Preferable linking groups include O, S, NR , or the like. When two or more R s are contained in the formula, they can be the same or different each other.

The alkyl group or alkylene group of R⁸ and R⁹, although it may be chain-like (branched or straight chain) or cyclic, is respectively preferably chain-like. The alkyl group and alkylene group may respectively have a substituent, examples of the substituents include an ethyl group, a propyl group (including an isopropyl group), or hydroxy group,.

n represents an integer of 1 to 4.

{0015}

The second water-soluble organic solvent is preferably a solvent selected from the group consisting of ethylene glycol monomethyl ether (EGME), ethylene glycol monoethyl ether (EGEE), ethylene glycol monopropyl ether (EGPE), ethylene glycol monobutyl ether (EGBE), propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether (PGEE), propylene glycol monopropyl ether (PGPE), propylene glycol monobutyl ether (PGBE), diethylene glycol monomethyl ether (DEGME), diethylene glycol monoethyl ether (DEGEE), diethylene glycol monopropyl ether (DEGPE), diethylene glycol monobutyl ether (DEGBE), dipropylene glycol monomethyl ether (DPGME), dipropylene glycol monoethyl ether (DPGEE), dipropylene glycol monopropyl ether (DPGPE), dipropylene glycol monobutyl ether (DPGBE), triethylene glycol monomethyl ether (TEGME), triethylene glycol monoethyl ether (TEGEE), triethylene glycol monopropyl ether (TEGPE), triethylene glycol monobutyl ether (TEGBE), tripropylene glycol monomethyl ether (TPGME), tripropylene glycol monoethyl ether (TPGEE), tripropylene glycol monopropyl ether (TPGPE), and tripropylene glycol monobutyl ether (TPGBE).

{0016}

The second water-soluble organic solvent is incorporated in the stripping solution in an amount of at least 1% by mass, preferably at least 2% by mass and more preferably at least 3% by mass. It is incorporated in the upper limit of equal to or less than 15% by mass, preferably equal to or less than 12% by mass and more preferably equal to or less than 10% by mass. Incorporation of the second water-soluble organic solvent in the lower limit or above preferably makes it possible to more efficiently dissolve a resist stripper (Hansen solubility Parameter due to the second solvent can be adjusted to a desirable range). On the other hand, setting to the upper limit or below preferably makes it possible to efficiently dissolve the resist stripper (a preferable value of Hansen solubility Parameter can be maintained without materially changing Hansen solubility Parameter of the first solvent).

The second water-soluble organic solvent can be contained in the solution as one compound, two or more compounds, which are selected from the above exemplified compounds.

{0017}

(Amino alcohol compound)

The amino alcohol compound includes a compound represented by formula

(III).

>10

(III) ,N

R¹

{0018}

In the formula, R¹⁰ to R¹² respectively represent a hydrogen atom, an alkyl group or a hydroxyalkyl group. However, at least one of R¹⁰ to R¹² is a hydroxyalkyl group. When any one of R¹⁰ to R¹² is an alkyl group, the alkyl group is preferably having 1 to 8 carbon atom(s), more preferably having 1 to 4 carbon atom(s). The alkyl group of R¹⁰to R¹² can have a linking group in the chain, within the extent of the effect of the invention being expected. Preferable linking groups include O, S, NR^N, or the like. The alkyl group of R¹⁰ and R¹², although it may be chain-like (branched or straight chain) or cyclic, is respectively preferably chain-like. The alkyl group may respectively have a substituent, examples of the substituents include an amino group ( R^N ₂). The alkyl group of R¹⁰ to R¹² can preferably be represented as following formulae (III- 1) and (III-2).

- L^R-(X-L^R)_P-N^rN2 (ΠΙ-1)

- (X-L^R)_p-R^A (III-l) Here, L^R is an alkylene group of having 1 to 6 carbon atom(s), preferably having 1 to 3 carbon atom(s). p is an integer of 0 to 6, preferably 0 to 3. R^N is the same as above described R^A is an alkyl group of having 1 to 8 carbon atom(s), more preferably having 1 to 4 carbon atom(s). X is a linking group of O, S, or NR^N.

When any one of R¹⁰ to R¹² is an hydroxyalkyl group, the hydroxyalkyl group is preferably having 1 to 8 carbon atom(s), more preferably having 1 to 4 carbon atom(s). The hydroxyalkyl group of R¹⁰ to R¹² can have a linking group in the chain, within the extent of the effect of the invention being expected. Preferable linking groups include O, S, NR^N, or the like. The hydroxyalkyl group of R¹⁰ to R¹² can preferably be represented as following formula (III-3).

- L^R-(X-L^R)_p-OH (III-3)

Here, L^R, X, and p are the same as those defined in formulae (III-l) and (III-2). The number of a hydroxy group of the hydroxyalkyl group is arbitrary.

However, the number of the hydroxy group is preferably one or two, more preferably one, with respect to one substituent. When any one of R¹⁰ to R¹² is an alkyl group or a hydroxyalkyl group, those lying next to each other may combine together to form a ring.

Herein, the number of the hydroxyalkyl group of R¹⁰ to R¹² is preferably one or two. In other words, it is preferable for the amino alcohol compound represented by formula (III) to have a primary amine structure or a secondary amine structure, when compared to a tertiary amine structure.

{0019}

The amino alcohol compound is preferably a compound selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), N- methylethanolamine (NMEA), Ν,Ν-dimethylethanolamine (DMMEA), N- methyldiethanolamine (DEMEA), aminoethylethanolamine (AEMEA), N,N- dimethylaminoethylethanolamine (DMAEMEA), aminoethoxyethanol (AEE), N,N- dimethylaminoethoxyethanol (DMAEE), and propanolamine (MP A).

{0020}

The amino alcohol compound is incorporated in the stripping solution in an amount of at least 1% by mass, preferably at least 2% by mass and more preferably at least 3% by mass. It is incorporated in the upper limit of equal to or less than 15% by mass, preferably equal to or less than 12% by mass and more preferably equal to or less than 10% by mass. Incorporation of the amino alcohol compound in the above- described lower limit or above preferably enables promotion of the reactions to resist and acceleration of solubility behavior.

On the other hand, setting to the upper limit or below preferably makes it possible (a preferable value of Hansen solubility Parameter can be maintained without materially changing Hansen solubility Parameter of the first solvent).

The amino alcohol compound can be contained as one compound, two or more compounds, which are selected from the above exemplified compounds.

{0021 }

Herein, when the compounding composition of the stripping solution is defined from a different perspective, the following range is preferable. The content of the second water-soluble organic solvent is preferably from 1 to 10 parts by mass and more preferably from 1 to 8 parts by mass, with respect to 100 parts by mass of the first water-soluble organic solvent. With respect to amino alcohol compound, the content is preferably from 1 to 10 parts by mass and more preferably from 1 to 8 parts by mass, with respect to 100 parts by mass of the first water-soluble organic solvent. Thus, the compounding ratio based on the first water-soluble organic solvent which acts as a main component preferably enables more prompt adjustment to functions of each component.

Further, with respect to the stripping properties which can be achieved by the present invention, it is also preferred that compounding adjustment is performed using Hansen Parameter which is defined by three parameters consisting of hydrogen bonding (hydrogen bonding: fn), polarity (polar: fp) and dispersion (dispersion: fd). When a preferable range of each of the parameters is indicated using three coordinates of the Hansen Parameter, it is preferred that the fh is from 20 to 30, the fp is from 45 to 65 and the fd is from 35 to 50.

{0022}

When a polymer such as a resist and the like is removed, it is thought to select a solvent that is easy to be compatible with the polymer. The properties of the solvent may be classified, for example, using the above-described Hansen Parameter (definition by three terms of dispersion term, polarity term and hydrogen bonding term). As a method of using this, it is thought that by finding a Hansen Parameter region that is preferable for dissolving the particular polymer, a solvent having such physical properties is selected.

From this point of view, it is possible to investigate a solvent appropriate to a certain particular polymer (a solvent having a preferable range of Hansen Parameter value). However, on the other hand, since deviation from the original Hansen

Parameter value is ordinarily caused due to addition of a second solvent and a third solvent, the compounding adjustment is not easy. That is to say, a careful setting of an addition concentration range including compounds to be used in combination is important to maintain a preferable range of Hansen Parameter value. For example, in a case of a mixed solvent consisting of dimethyl sulfoxide and monoethanolamine, the Hansen Parameter value varies considerably depending on a concentration thereof. In other words, it is said that what is a diffluent polymer becomes different. In

consideration of the above points, the present invention enables provision of the stripping solution having comprehensively improved properties to a broad range of resist species, and in addition, provision of the stripping solution set to a Hansen

Parameter range that is suitable for dissolving a positive-type resist in particular in its preferable embodiment.

{0023}

(Non-aqueous stripping solution)

In the present invention, the term "non-aqueous" means to contain substantially no water in the liquid. The content of water is preferably less than 3% by mass, more preferably less than 2% by mass, and still more preferably less than 1 % by mass.

Especially it is preferred that completely no water is incorporated. Further, it is preferred that completely no water is incorporated. Further, it is preferred that the stripping solution of the present invention incorporate substantially no onium salt. As an embodiment in which water or an onium salt is not substantially incorporated, these components may be incorporated, as long as it exhibits a desirable effect. For example, such embodiment includes an embodiment in which the stripping solution inevitably contains minute amounts of these components (for example, an embodiment in which it contains moisture absorbed from an atmosphere at the time of storage or use). {0024}

(Other component)

The stripping solution of the present invention may contain, other than the above-described components, an inhibitor to a metal on the substrate (corrosion inhibitor), a surfactant, an antifoamer or the like. The surfactant may be used by selecting appropriately from known nonionic surfactants, cationic surfactants, amphoteric surfactants and the like. The corrosion inhibitor may be used by selecting appropriately from nitrogen-containing compounds such as azoles, compounds known as a chelate compound such as ethylenediammine tetra acetic acid, and the like. As the antifoamer, known compounds such as acetylene alcohol and silicone oil may be used appropriately.

{0025}

The resist that is applied to the resist strip process of the present invention is not particularly limited and known resist materials may be used. Examples of the resist include a positive type photoresist, a negative type photoresist and a positive- negative type photoresist. Specific examples of the positive type resist include vinyl cinnamate-based, cyclized polyisobutyrene-based, azo-novolac resin-based, and diazoketone-novolac resin-based resists. Further, specific examples of the negative type resist include azide-cyclized polyisoprene-based, azide-phenol resin-type, and chloromethyl polystyrene-based resins. Further, specific examples of the positive- negative type resist include poly (p-butoxycarbonyloxystyrene)-based resins.

{0026}

In the present invention, application to the positive type resist among them is preferred. In particular, the present invention has a beneficial effect on the stripping of the positive type resist including at least one of a novolac resin and a

polyhydroxystyrene resin. This reason is not clear, but it is estimated that an alkanol amine compound acts on the phenol site or the substituted phenol (those in which a hydrogen atom of the -OH group of the phenol is substituted with an organic group such as an alkyl group) site of the above-described resin, whereby the resin becomes easy to be dissolved in the stripping solution. Further, because of good stripping properties, the stripping solution of the present invention exhibits an effect on the stripping of the resist layer that is a thick film having a thickness of from 5 to 500μιη in particular.

{0027}

More specific examples of the positive type resist including at least one of a novolac resin and a polyhydroxystyrene resin include a positive type resist containing a resin having a recurring unit represented by any one of the following formulae (R-l) and (R-2).

{0028

{0029}

In the formulae, R¹³ to R¹⁷ each independently represent a hydrogen atom or an alkyl group. The preferable range of an alkyl group has the same meaning as that of R¹ to R⁵.

The molecular weight of the above-described resin, although it is not particularly limited, is ordinarily from 1000 to 1000000, preferably from 2000 to 100000, and more preferably from 3000 to 50000, in terms of polystyrene-reduced weight-average molecular weight.

{0030}

Semiconductor substrate>

As a semiconductor substrate (a substrate for a semiconductor element) that is a processing target of the above-described washing treatment, an arbitrary

semiconductor substrate may be used. The semiconductor substrate to be used is not particularly limited, and it may have an insulating film such as a silicon dioxide film and a silicon nitride film, a wiring metal such as aluminum (Al) and copper (Cu), a tantalum nitride film (TaN), a Titanium nitride film (TiN), a hafnium oxide layer (Hf0₂), a Lanthanum oxide layer (La₂0₃), an Aluminum oxide layer (A1₂0₃), polysilicon, a dope (argon, carbon, neon, arsenic and the like ) silicon and the like on a partial or entire surface thereof.

Note that in the present invention, the semiconductor substrate is used as a generic name of an intermediate (precursor) that produces a semiconductor element, and means to include not only a silicon wafer, but also in-process materials that are unimplemented, and that are provided thereon an insulating film, an electrode and the like.

{0031 }

(Resist strip process)

Although the resist strip process in the present invention is not particularly limited, may be performed by a single wafer type or batch type apparatus. The single wafer type is a method of etching each wafer. One embodiment of the single wafer type is a method of processing by spreading a processing liquid entirely over the surface of a wafer using a spin coater.

The liquid temperature of the stripping solution, the discharge rate of the stripping solution, and the rotation number of wafer of the spin coater are used by selecting appropriate values through selection of the wafer as a target.

{0032}

In the present embodiment, the conditions under which a resist stripping process is performed are not limited, but a stripping process of the single wafer processing is preferred. In the stripping process of single-wafer-type, semiconductor substrates are transported or rotated in the predetermined direction, and a stripping solution is discharged in a space between them to put the stripping solution on the semiconductor substrate. According to the necessity, stripping solution may be sprayed while rotating the semiconductor substrate using a spin coater. On the other hand, in the batch-type stripping, a semiconductor substratme is immersed in a liquid bath constituted of a stripping solution to put the stripping solution on the

semiconductor substrate. It is preferable for these stripping methods to be used appropriately and selectively depending on a structure, a material and the like of the element.

{0033}

The temperature at which the stripping is performed is not particularly limited, the temperature of equal to or less than 35°C is preferable; the temperature of equal to or less than 30°C is more preferable. With respect to the stripping solution of the present invention, even in a relatively low temperature case, the lower limit of the temperature at which the stripping is performed is not particularly limited, as long as the stripping solution exists as a liquid. However, it is preferable to perform the stripping at 15°C or above from the viewpoint of throughput or the like at the time of production. In the case of the single wafer processing, the supply rate of the stripping solution is not particularly limited, even though the rate may depend on the size of the semiconductor substrate, the supply rate is set to a range of preferably from 0.3 to 3 L/minute, and more preferably from 0.5 to 2 L/minute. It is preferable to set the supply rate to the above-described lower limit or more because uniformity in a plane can be ensured by the supply rate. It is preferable to set the immersion time to the above-described upper limit or less because stable performance at the time of continuous processing can be ensured by the immersion time. When the semiconductor substrate is rotated, it is preferable from the same view point as the above to rotate the semiconductor substrate at a rate from 100 to 1,000 rpm, even though the rate may depend on the size or the like of the semiconductor substrate.

Note that the term "temperature" here is a surface temperature of the treating substrate in the case of the single wafer processing, while it is a liquid temperature of the stripping solution in the butch in the case of the butch-type processing.

{0034}

(Chemical liquid supply system and temperature regulation)

In the present invention, although the temperature-regulated chemical liquid supply line system is not particularly limited, preferable examples thereof are described below. The term "temperature regulation" herein used refers to maintaining the chemical liquid at a predetermined temperature. Ordinarily, the chemical liquid is maintained by heating at a predetermined temperature.

Examples of chemical supply line

(1) (a) Chemical storage tank→ (b) Temperature-regulating tank→ (c) Inline temperature regulation→ (d) Ejection to wafer→ Return to (a) or (b).

(2) (a) Chemical liquid tank→ (b) Temperature-regulating tank→ (d) Ejection to wafer → Return to (a) or (b).

(3) (a) Chemical liquid tank→ (c) Inline temperature regulation→ (d) Ejection to wafer→ Return to (a)

(4) (a) Chemical liquid tank→ (b) Temperature-regulating tank→ (e) Bath (Circulation temperature regulation).

(5) (a) Chemical liquid tank→ (e) Bath (Circulation temperature regulation).

(6) (b) Temperature-regulating tank→ (d) Ejection to wafer→ Return to (b).

(7) (b) Temperature-regulating tank→ (c) Inline temperature regulation→ (d) Ejection to wafer→ Return to (b).

(8) (b) Temperature-regulating tank→ (e) Bath (Circulation temperature regulation). The above methods are used.

{0035}

The chemical liquid already used in the method of the present invention can be re-used by circulation. Preferable method is not "free-flowing" (without re-use), but re-use by circulation. It is possible to continue circulation for 1 hour or longer after heating, which makes it possible to perform a repetitive treatment. Although there is no particular upper time limit of the circulating-reheating, exchange within a week is preferable because stripping properties deteriorates with age. The exchange within 3 days is more preferable. An exchange to a flesh liquid once a day is particularly preferable. In the stripping process of the above-described line system, the

measurement position of the temperature-regulated temperature may be determined appropriately by the relation to a line configuration or a wafer. Typically, the measurement position is regulated by adjusting the tank temperature. In the case where relatively more strict conditions in terms of performance are required, wherever the measurement and the regulation are feasible, the temperature-regulated temperature may be defined by a wafer surface temperature. In this case, temperature measurement can be conducted using a radiation thermometer.

{0036}

[Method of producing a semiconductor element]

The method of producing a general semiconductor element is as follows. At first, a gate insulator film that is composed of a high-dielectric constant material (for example, HfSi0₄, Zi0₂, ZiSi0₄, A1₂0₃, Hf0₂, La₂0₃) and the like, and a gate electrode layer that is composed of a polysilicon and the like are formed on a silicon substrate (ion-implanted n-type or p-type silicon substrate) using a technique such as spattering or the like (an etching layer-forming process). Next, a resist is coated on the formed gate insulator film and the gate electrode layer and a predetermined pattern is formed by photolithography. After pattern formation, an unnecessary portion of the resist is removed by development (a resist development process) and then using the resist pattern as a mask, the non-mask region is subjected to dry etching or wet etching (an etching process), thereby removing the gate insulator film and the gate electrode layer. Then, in an ion implantation treatment (an ion plantation process), an ionized p-type or n-type impurity element is implanted into a silicon substrate, thereby forming a p-type or n-type impurity implantation region (so-called source/drain region). Then, if needed, an ashing treatment (an ashing process) is carried out, and then a process of stripping a resist film remaining on the substrate is carried out.

EXAMPLES

{0037}

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited thereto. The content (parts) and concentration (%) are defined in a mass basis, unless otherwise particularly described.

{0038}

The resist stripping solutions designed to have components and compositions (% by mass) shown in the following Table were prepared.

Test wafer: a film of PMER P-CA 1000PM (novolak resin-containing positive-type resist, manufactured by TOKYO OHKA KOGYO CO., LTD.) with a film thickness of ΙΟμιη was produced. A prepared stripping solution was ejected from above the wafer under the following conditions to evaluate stripping performances of the resist layer. · Processing temperature: 25°C

• Discharge rate: 1 L/min. • Wafer rotation number 500 rpm

• Processing time 1 min.

In addition, the processing temperature was measured as follows. A radiation thermometer IT-550F manufactured by HORIBA Ltd. was fixed at the height of 30cm from a wafer in the single wafer equipment. Temperature was measured while flowing the chemical liquid in a manner such that the thermometer was pointed to a wafer surface at the distance of 2cm outside from the center of the wafer. Measurement data was output digitally from the radiation thermometer and recorded using a personal computer.

{0039}

[Removal performance of the resist]

A surface of the wafer after stripping test was observed using light microscope to evaluate removal performance of the resist.

AA: Resists were completely removed.

A: Resists were approximately completely removed.

B: Resist remained undissolved as a faulty dissolved material.

C: Almost no resist was removed.

{0040}

Testing wafer: A semiconductor substrate (specimen) constituted of a silicon wafer on which a Al layer, a TiN layer and a SiOx layer were disposed in the state of alliance for test and evaluation were prepared. The stripping solution was supplied to the semiconductor substrate, under the following conditions using a single wafer-type apparatus (POLOS (trade name), manufactured by SPS-Europe B.V.), and the evaluation test was conducted. Evaluation was conducted in terms of etching rate (RAI, R™, Rsio) of each of the metal layers.

• Processing temperature: 25°C

• Discharge rate: 1 L/min.cc

• Wafer rotation number 500 rpm

· Processing time 1 Hour {0041}

Table 1

{0042}

Table 2

{0043}

Table 3

{0044}

Table 4-1

{0045}

Table 4-2

{0046}

• The conditions of Tests 200, 300 and 400 are the same as Test 100.

• Target resist

A: (positive-type) P-CA1000PM (trade name, manufactured by TOKYO OHKA

KOGYO Co., Ltd.)

B: (positive-type) PMER P-LA900PM (trade name, manufactured by TOKYO

OHKA KOGYO Co., Ltd.)

C: (positive-type) AZ4903 (trade name, manufactured by Clariant (Japan) K.K.) D: (negative-type) SU-8 3000 (trade name, manufactured by Nippon Kayaku Co.,

Ltd.)

E: (negative-type) PMER N-C A3000PM (trade name, manufactured by TOKYO OHKA KOGYO Co., Ltd.)

• Reagents (other than those of which abbreviations are described in the present specification)

NMP: N-methylpyrrolidone

TEA: Triethanolamine

• cone: concentration (mass %)

• lA =10nm

{0047}

From the above results, it is found that a resist stripping solution and a resist removal process of the present invention are capable of favorably responding to removal of not only a negative -type resist resin but also a positive-type resist such as a novorak resin. In addition, it is found that a resist stripping solution and a resist removal process of the present invention are capable of effectively stripping, without damaging a substrate material, the resist existing thereon, even in a low temperature of near room temperature.

{0048}

Having described our invention as related to the present embodiments, it is our intention that the invention not be limited by any of the details of the description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.

{0049}

This application claims priority on Patent Application No. 2012-183522 filed in Japan on August 22, 2012, which is entirely herein incorporated by reference.

Claims

{Claim 1 }

A resist stripping solution for stripping a resist on a substrate, being prepared in a non-aqueous condition, the resist stripping solution comprising:

(1-1 ) (1-2) (1-3) (II) (HO wherein, in the formulae, R¹ to R⁵ respectively represent a hydrogen atom or an alkyl group; R⁶ and R⁷ respectively represent a hydrogen atom, an alkyl group or an alkoxy group; R⁹ represents a hydrogen atom or an alkyl group; R¹⁰ to R¹² respectively represent a hydrogen atom, an alkyl group or a hydroxyalkyl group; however, at least

1 0 17 a

one of R to R represent a hydroxyalkyl group; R represents an alkylene group; n represents an integer of 1 to 4.

{Claim 2}

The resist stripping solution according to Claiml,

wherein the first water-soluble organic solvent is a solvent selected from the group consisting of dimethyl sulfoxide (DMSO), dimethylacetamide (DMAc), dimethylformamide (DMF), methylethyl ketone (MEK), methylisobutyl ketone (MIK), cyclohexanone (CHN), cyclopentanone (CPN), methylpropyl ketone (MPK), and 2- hydroxyisobutyric acid methyl (HBM). {Claim 3}

The resist stripping solution according to Claim 1 or 2,

wherein the second water-soluble organic solvent is a solvent selected from the group consisting of ethylene glycol monomethyl ether (EGME), ethylene glycol monoethyl ether (EGEE), ethylene glycol monopropyl ether (EGPE), ethylene glycol monobutyl ether (EGBE), propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether (PGEE), propylene glycol monopropyl ether (PGPE), propylene glycol monobutyl ether (PGBE), diethylene glycol monomethyl ether (DEGME), diethylene glycol monoethyl ether (DEGEE), diethylene glycol monopropyl ether (DEGPE), diethylene glycol monobutyl ether (DEGBE), dipropylene glycol monomethyl ether (DPGME), dipropylene glycol monoethyl ether (DPGEE), dipropylene glycol monopropyl ether (DPGPE), dipropylene glycol monobutyl ether (DPGBE), triethylene glycol monomethyl ether (TEGME), triethylene glycol monoethyl ether (TEGEE), triethylene glycol monopropyl ether (TEGPE), triethylene glycol monobutyl ether (TEGBE), tripropylene glycol monomethyl ether (TPGME), tripropylene glycol monoethyl ether (TPGEE), tripropylene glycol monopropyl ether (TPGPE), and tripropylene glycol monobutyl ether (TPGBE).

{Claim 4}

The resist stripping solution according to any one of Claims 1 to 3, wherein the amino alcohol compound is a compound selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), N- methylethanolamine (NMEA), N,N-dimethylethanolamine (DMMEA), N- methyldiethanolamine (DEMEA), aminoethylethanolamine (AEMEA), N,N- dimethylaminoethylethanolamine (DMAEMEA), aminoethoxyethanol (AEE), N,N- dimethylaminoethoxyethanol (DMAEE), and propanolamine (MP A). {Claim 5}

The resist stripping solution according to any one of Claims 1 to 4,

wherein each of from 1 to 10 parts by mass of the second water-soluble organic solvent and from 1 to 10 parts by mass of an organic amine compound is compounded with respect to 100 parts by mass of the first water-soluble organic solvent.

{Claim 6}

The resist stripping solution according to any one of Claims 1 to 5,

wherein the resist to be removed is a positive-type resist.

{Claim 7}

The resist stripping solution according to any one of Claims 1 to 6,

wherein the resist is a positive-type resist comprising at least one of a novorak resin and a polyhydroxystyrene resin.

{Claim 8}

The resist stripping solution according to any one of Claims 1 to 7,

wherein the resist is applied to a resist stripping at the temperature of equal to or less than 35°C.

{Claim 9}

A resist strip process comprising the steps of preparing a resist stripping solution and applying the resist stripping solution onto a semiconductor substrate so as to strip a resist on the semiconductor substrate;

the resist stripping solution comprising:

(1-1 ) (1-2) (1-3) (II) OH) wherein, in the formulae, R¹ to R⁵ respectively represent a hydrogen atom or an

6 7

alkyl group; R and R respectively represent a hydrogen atom, an alkyl group or an alkoxy group; R⁹ represents a hydrogen atom or an alkyl group; R¹⁰ to R¹² respectively represent a hydrogen atom, an alkyl group or a hydroxyalkyl group; however, at least one of R¹⁰ to R¹² represent a hydroxyalkyl group; R⁸ represents an alkylene group; n represents an integer of 1 to 4.

{Claim 10}

The resist strip process according to Claim 9,

wherein the resist to be removed is a positive-type resist.

{Claim 1 1 }

The resist strip process according to Claim 9 or 10,

{Claim 12}

The resist strip process according to any one of Claims 9 to 1 1,

wherein the thickness of a resist layer is from 5 to 500μηι.

{Claim 13}

The resist strip process according to any one of Claims 9 to 12, wherein application of the resist stripping solution onto the semiconductor substrate is performed at the temperature of equal to or less than 35°C.

{Claim 14}

A method for producing a semiconductor substrate product comprising stripping a resist on a semiconductor substrate in accordance with a resist strip process according to any one of Claims 9 to 13, and then producing the semiconductor substrate product using the processed semiconductor substrate.