JP5052410B2 - Photoresist developer - Google Patents

Description

  The present invention relates to a novel photoresist developer used in the manufacture of semiconductor devices, flat panel displays (FPD), circuit boards, magnetic heads, and the like, and in particular, consists of a chemical amplification resist (Chemical Amplification Resist) and the like. The present invention relates to a photoresist developer that can be suitably used for developing a thick-film photoresist.

  Importance of precision processing technology to form and process fine devices in a wide range of fields, including the manufacture of semiconductor integrated circuits such as LSI, the display surface of FPD, and the manufacture of circuit boards such as magnetic heads. Has increased. In such precision processing technology, a processing means called photofabrication has become mainstream. Photofabrication is a process in which a photosensitive resin composition called a photoresist is applied to the surface of a workpiece to form a coating film (resist layer) and exposed, and then the exposed coating film is patterned with a developer. (Resist pattern formation), a technique for forming various elements and wiring patterns by performing electroforming (specifically, chemical etching, electrolytic etching, electroplating, or a combination thereof) using this as a mask. It is used for manufacturing various precision parts such as semiconductor packages.

  An alkaline aqueous solution is used as a developing solution in the photofabrication as described above, but if such an alkaline aqueous solution contains metal ions, the electrical characteristics of the resulting semiconductor package or the like will be adversely affected. . For this reason, an aqueous alkali solution containing no metal ions, for example, an aqueous solution of an organic quaternary ammonium compound such as tetramethylammonium hydroxide (hereinafter sometimes referred to as TMAH) is widely used as a developing solution.

  In addition, when patterning a resist layer using a developer, resist patterns that match the exposure pattern with high accuracy can be prevented by preventing the resist components eluted in the developer from re-adhering to the gaps in the resist pattern. Is necessary to form. The resist component reattached is called scum, but the occurrence of scum causes a decrease in the adhesion between the substrate and the conductor in the subsequent conductor plating step. Many developers have been proposed in which a surfactant is added to an aqueous solution of a quaternary ammonium compound as a developer capable of preventing the occurrence of such scum and forming a highly accurate resist pattern.

  For example, Patent Documents 1 and 2 propose a developer comprising a tetramethylammonium hydroxide aqueous solution to which a nonionic surfactant and a cationic surfactant are added. Patent Document 3 proposes a developer composed of an aqueous solution of a quaternary ammonium compound to which an anionic surfactant is added.

  On the other hand, in recent years, with the downsizing of electronic equipment, high-density packaging technology for semiconductor packages has progressed. For example, in order to package LSI, a multi-pin thin film mounting method in which protruding electrodes are provided as connection terminals on a substrate surface Has been applied. In this multi-pin thin film mounting method, connection terminals (projection electrodes) composed of bumps projecting from the substrate surface, and connection terminals composed of columns called metal posts projecting from the substrate and solder balls formed on the columns are used. Then, packaging of LSI or the like is performed. For such bumps and metal posts, a thick photoresist layer having a thickness of 3 μm or more, particularly 8 μm or more is formed on the substrate surface, and a photoresist pattern having a line width of 5 μm or more is formed by exposure and development. Subsequently, a conductor such as copper is buried in the resist gap portion (the substrate surface portion that is not coated with the resist and exposed) by plating or the like, and finally the surrounding resist pattern is removed.

  The photoresist developers disclosed in Patent Documents 1 to 3 described above can form a very fine pattern when developing a photoresist layer having a thickness of about 1.5 μm, and have an excellent effect. Demonstrate. However, as the thickness of the photoresist layer increases, the amount of the resist component dissolved in the developer increases, which causes problems such as increased scum generation, and a fine resist pattern can be formed with high accuracy. For example, in the case of developing a photoresist layer having a thickness of 3 μm or more with the developer as described above, the occurrence of scum increases, and the development characteristics need to be improved.

  In view of the above, the present inventors disclosed in Patent Document 4 a quaternary ammonium containing a nonionic surfactant and a cationic surfactant as a developer for developing a thick photoresist layer. A developer comprising an aqueous solution of the compound is proposed. This developer can sufficiently cope with development of a photoresist layer having a thickness of 3 μm or more.

Japanese Patent Publication No. 6-3549 JP 2002-169299 A Japanese Patent No. 2589408 International Publication No. WO06 / 134902 Pamphlet

  By the way, the patterning of the photoresist layer is performed by, for example, irradiating light such as ultraviolet rays in a predetermined pattern (exposure), and modifying the base resin (photosensitive resin) in the photoresist layer in the exposed portion (photosensitive resin). Then, a positive or negative resist pattern is formed according to the exposure pattern by eluting and removing the exposed or unexposed resist component with a developer. is there. In recent years, there has been an attempt to shorten the exposure time in a thick photoresist layer to improve productivity and dimensional accuracy, and a chemically amplified resist that can be finely processed with higher sensitivity than a novolak-diazonaphthoquinone type resist. Increasing use. A chemically amplified resist is a compound in which a photoacid generator is blended in addition to a photosensitive resin. The acid generated by light irradiation functions as a catalyst, and the photosensitive resin is denatured (alkali solubilized by heating after exposure). Alternatively, alkali insolubilization) is promoted. A thick photoresist layer formed using such a chemically amplified resist not only shortens the exposure time and improves productivity, but also has a high sensitivity, so that a resist pattern with high dimensional accuracy can be formed. It becomes possible.

  However, according to the study by the present inventors, the developer proposed in Patent Document 4 does not exert a sufficient effect on a thick photoresist layer formed using a chemically amplified resist, There is a drawback that the resist pattern is likely to have a defective shape, and further development characteristics are required.

  Accordingly, the object of the present invention is to effectively prevent the occurrence of scum even when developing a photoresist layer having a thickness of 3 μm or more, particularly a thick photoresist layer formed of a chemically amplified resist. It is an object to provide a photoresist developer capable of forming a high resist pattern.

  The present inventor has intensively studied to achieve the above object. As a result, it has been found that a photoresist developer in which a specific anionic surfactant and a cationic surfactant are added to an aqueous solution of a quaternary ammonium compound can solve the above problems, and the present invention has been completed.

According to the present invention, in a photoresist developer comprising an aqueous solution of a quaternary ammonium compound,
The aqueous solution of the quaternary ammonium compound contains an anionic surfactant and a cationic surfactant,
The quaternary ammonium compound is a strongly basic quaternary lower alkyl ammonium hydroxide,
The anionic surfactant has the following formula (1):

(In the formula, p is an integer of 1 to 3, m is an integer of 5 to 30, R ¹ is a hydrogen atom or a methyl group, and R ² is a hydrogen atom or a carbon number of 1 to 4. A is an alkylene group having 2 to 4 carbon atoms, and a plurality of divalent groups AO may be the same or different from each other, and M is a hydrogen atom or an ammonium ion. Is)
And 0.1 to 5% by mass of the anionic surfactant and 0.01 to 2% of the cationic surfactant when the total mass of the photoresist developer is 100% by mass. A photoresist developer characterized by containing at a concentration of mass% is provided.

In the photoresist developer of the present invention,
(1) The cationic surfactant is represented by the following formula (2):

(Wherein R ³ , R ⁴ and R ⁵ are each a hydrogen atom or an organic group having 1 to 20 carbon atoms, and X is OH, Cl, Br or I)
A quaternary ammonium salt represented by
(2) The anionic surfactant has a molecular weight of 600 to 1,500,
(3) The total concentration of sodium ions and potassium ions is suppressed to 500 ppb or less,
Is preferred.

  According to the present invention, there is also provided a photoresist developing method characterized by using the above-mentioned photoresist developer for developing an exposed thick film resist layer having a thickness of 3 μm to 100 μm.

  When the photoresist developer of the present invention is used, even if a thick photoresist layer having a film thickness of 3 μm or more, particularly 10 μm or more is developed, no scum is generated and a good pattern shape can be maintained. Is possible. In particular, even when the thick-film photoresist layer is made of a chemically amplified resist, since a scum is not generated and a good resist pattern with high dimensional accuracy can be formed, its industrial utility value is very high. .

  In the present invention, the specific anionic surfactant represented by the general formula (1) and the cationic surfactant are mixed in an aqueous solution of a quaternary lower alkyl ammonium hydroxide, thereby The following effects are estimated by the present inventors for the reason as follows.

  That is, during development, an anionic surfactant adheres to the resist surface, and this surfactant effectively prevents the occurrence of scum (that is, the adhesion of the resist component dissolved in the developing solution), thereby effectively reducing the shape of the resist pattern. On the other hand, the cationic surfactant has the function of preventing excessive dissolution of the resist component into the developer and preventing the resist pattern from being deteriorated by erosion of the developer. It seems that a resist pattern with high dimensional accuracy can be formed because the functions are exhibited simultaneously. For example, as understood from the experimental results of Examples described later, in the developer containing only the anionic surfactant and not containing the cationic surfactant (Comparative Production Example 2), the occurrence of scum is suppressed. Although the resist pattern shape cannot be maintained, on the other hand, an anionic surfactant and a cationic surfactant are blended, but a developer with a small amount of an anionic surfactant (comparison) This is because in Production Example 3), the occurrence of scum cannot be prevented.

The photoresist developer of the present invention is obtained by adding a specific anionic surfactant and a cationic surfactant to an aqueous solution of a quaternary ammonium compound, and each component will be described below.
<Quaternary ammonium compound aqueous solution>
In the present invention, an aqueous solution of a quaternary ammonium compound to which various surfactants are added is strongly basic and dissolves an alkali-soluble material from the exposed photoresist layer. It is the main component of the liquid. This aqueous solution does not substantially contain alkali metal ions or the like and does not adversely affect the electrical characteristics of the finally obtained semiconductor package or the like.

  This quaternary ammonium compound has been conventionally known as a component of a photoresist developer. Specifically, the quaternary ammonium compound has high solubility in a resist component after exposure, and the developer can be removed by a cleaning solution (rinse solution) after development. From the standpoint of ease, a strongly basic quaternary lower alkyl ammonium hydroxide having a pH (25 ° C.) of 12 or more in a 1% strength by weight aqueous solution is used.

  In the quaternary lower alkyl ammonium hydroxide, lower alkyl means an alkyl group having 3 or less carbon atoms.

  Such quaternary ammonium hydroxides are roughly classified into tetra-lower alkyl ammonium hydroxides and tri-lower alkyl (hydroxy lower alkyl) ammonium hydroxides.

  Examples of tetra lower alkyl ammonium hydroxide include tetramethyl ammonium hydroxide (TMAH), tetraethyl ammonium hydroxide, tetrapropyl ammonium hydroxide, trimethyl ethyl ammonium hydroxide, and tri-lower alkyl (hydroxy lower alkyl). ) Examples of ammonium hydroxide include trimethyl (2-hydroxyethyl) ammonium hydroxide, triethyl (2-hydroxyethyl) ammonium hydroxide, tripropyl (2-hydroxyethyl) ammonium hydroxide, trimethyl (1-hydroxypropyl) ) Ammonium hydroxide and the like. These quaternary lower alkylammonium hydroxides are used in the form of an aqueous solution either individually or in combination of two or more. Particularly preferred among the above are TMAH and trimethyl (2-hydroxyethyl) ammonium hydroxide. This is because they are highly basic and highly water-soluble, and the aqueous solution easily elutes the resist components after exposure and can be easily washed and removed by the rinse solution after exposure.

In addition, the concentration of the quaternary lower alkyl ammonium hydroxide described above varies depending on the type of the quaternary lower alkylammonium hydroxide, and thus cannot be generally limited. % Is in the range of 0.1 to 10% by mass, particularly 1 to 5% by mass. When the concentration of the quaternary lower alkyl ammonium hydroxide satisfies the above range, it is possible to selectively elute and remove alkali-soluble substances to be removed from the photoresist layer after exposure. Patterning is possible.
<Anionic surfactant>
In the present invention, as the anionic surfactant added to the aqueous solution of the quaternary lower alkyl ammonium hydroxide, a compound represented by the following formula (1) is used.

In the formula, p is an integer of 1 to 3, m is an integer of 5 to 30, R ¹ is a hydrogen atom or a methyl group, and R ² is a hydrogen atom or a carbon number of 1 to 4. An alkyl group, A is an alkylene group having 2 to 4 carbon atoms, may be branched, and a plurality of divalent groups AO may be the same or different from each other; M is a hydrogen atom or an ammonium ion.

As described above, such an anionic surfactant is considered to function to suppress the occurrence of scum. Among them, compounds having a molecular weight in the range of 600 to 1,500 are scum. It is preferably used because it greatly contributes to the suppression of the occurrence of If this molecular weight is too low, it is considered that the surface activity is lowered, and the effect of maintaining the pattern shape tends to be lowered. Also, when the molecular weight is too high, the ratio of functional groups (SO ₃ M groups) in the molecule decreases, so the ratio of functional groups in the photoresist developer also decreases, and the surface-active effect is also lowered. Therefore, it is estimated that the effect of suppressing the occurrence of scum is not sufficient and the effect of maintaining the pattern shape is reduced. Examples of the anionic surfactant having a molecular weight within the above range include the following compounds.

  The above anionic surfactants can be used alone or in combination of two or more.

  In the present invention, the anionic surfactant is 0.1 to 5% by mass, preferably 0.5 to 5.0% by mass, most preferably 1. It mix | blends in the quantity of 0-5.0 mass%. If this amount is less than the above range, the occurrence of scum cannot be suppressed, and the effect of maintaining the pattern shape will be reduced. If it is added in a larger amount than the above range, it will be removed from the photoresist layer. The resist component is eluted from a portion other than the power portion (for example, an unexposed portion of the positive resist), and the deterioration of the resist pattern shape is increased.

Although described in detail below, since the photoresist developer of the present invention preferably suppresses the content of sodium ions and potassium ions to a certain level or less, the alkali metal contained in the anionic surfactant described above is used. It is preferable to have as few ions as possible. That is, in the production of the anionic surfactant, alkali metal ions (sodium ions and potassium ions) may be included as unavoidable impurities, but such alkali metal ions are suppressed to 10 ppm or less. It is preferable to use what is. The amount of alkali metal ions can be easily reduced by purification in contact with a hydrogen-type cation exchange resin or the like.
<Cationic surfactant>
In the present invention, in addition to the anionic surfactant described above, a cationic surfactant is used. By using such a cationic surfactant, for example, excessive resist components are eluted in the developer. It is possible to effectively prevent the inconvenience that the pattern shape of the resist deteriorates. That is, in a developer not containing a cationic surfactant, the photoresist component is eluted into the developer from a region that should not be removed by development in the photoresist layer after exposure, and the shape of the resist pattern is reduced. It will deteriorate.

  In the present invention, known cationic surfactants that are generally available on the market can be used as such cationic surfactants. Typical examples thereof include higher alkyltrimethylammonium hydroxides or ammonium salts thereof. , Dialkyldimethylammonium hydroxide or its ammonium salt (at least one of the dialkyls is higher alkyl), benzylimidazolinium hydroxide or its imidazolinium salt, alkylbenzyldimethylammonium hydroxide or its ammonium salt, benzyl Pyridinium hydroxide or its pyridinium salt, benzyltrialkylammonium hydroxide or its ammonium salt, alkylpyridinium hydroxide or its pyridinium salt, polyoxyethylene alkyl base Examples thereof include zirconium hydroxide or an ammonium salt thereof, polyoxyethylene alkyltrialkylammonium hydroxide or an ammonium salt thereof, and these cationic surfactants may be used alone. Two or more kinds may be used in combination. Here, the higher alkyl means an alkyl group having 5 or more carbon atoms.

  In the developer of the present invention, a cationic surfactant represented by the following formula is preferable from the viewpoint that the effect of maintaining the resist pattern shape by the combination with the anionic surfactant described above is particularly high.

In the above formula, R ³ , R ⁴ and R ⁵ are each a hydrogen atom or an organic group having 1 to 20 carbon atoms, and the organic group may contain an ester bond, an ether bond or an amide bond. R ⁶ is a pyridinium group or an imidazolinium group, and R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are alkyl groups having 1 to 20 carbon atoms, and at least one of them is a carbon number. It is a higher alkyl group of 5 or more, R ¹² , R ¹³ and R ¹⁴ are each a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ¹¹ is an alkylene group having 2 to 20 carbon atoms. Further, q represents an integer of 5 to 20, and X represents OH, Cl, Br or I.

  Of the cationic surfactants represented by the above formula, the following compounds are more preferable.

(In the formula, X represents OH, Cl, Br or I.)
Among the various cationic surfactants described above, from the standpoint of exhibiting the most excellent effect and being easily available (manufacturing is easy), an optimum one is represented by the following formula (2): Can be mentioned.

In the formula, R ³ , R ⁴ , and R ⁵ are each a hydrogen atom or an organic group having 1 to 20 carbon atoms, and X is OH, Cl, Br, or I. In the above formula, the organic group represented by R ³ , R ⁴ and R ⁵ may include an ester bond, an ether bond or an amide bond.

  Among such optimum cationic surfactants, those most readily available are the following compounds.

(X is OH, Cl, Br, or I.)
The compounding amount of the cationic surfactant is 0.01 to 2.0% by mass, particularly 0.03 to 1.0% by mass, where the mass of the entire photoresist developer is 100% by mass. If this amount is less than the above range, the resist pattern shape deterioration suppressing effect is small, and if it is more than the above range, the developing speed becomes slow, impairing practicality.

In the present invention, the cationic surfactant is preferably used in a range where the mass ratio to the anionic surfactant (anionic surfactant: cationic surfactant) is 10 to 100: 1. It is. By using both components at such a mass ratio, resist pattern shape retention effect by preventing the occurrence of scum that anionic surfactants have and shape degradation due to excessive dissolution of resist components that have cationic surfactants Preventive effect is most effectively expressed in a balanced manner.
<Photoresist developer>
The photoresist developer of the present invention can be obtained by blending the above-mentioned anionic surfactant and cationic surfactant into an aqueous solution of a quaternary lower alkyl ammonium hydroxide, but does not impair the effects of the present invention. In addition to these surfactants, known additives conventionally used in developing solutions, for example, wetting agents, stabilizers, solubilizing aids, and the like can be appropriately blended.

  The total concentration of sodium ions and potassium ions in the photoresist developer is preferably suppressed to 500 ppb or less. If the amount of these alkali metal ions is larger than the above range, the electrical characteristics of the finally obtained semiconductor package and the like may be impaired, and the resist component is likely to be excessively eluted in the developer. This is because the pattern shape may be deteriorated. As described above, the suppression of the alkali metal ion concentration can be performed by purification in contact with a hydrogen-type cation exchange resin or the like.

Further, the photoresist developer of the present invention has a pH higher than 12.5, particularly preferably 13 or higher. By using such a strongly basic photoresist developer, the development speed is high and stable development can be performed. The pH adjustment of the photoresist developer can be realized by adjusting the concentrations of the quaternary lower alkyl ammonium hydroxide, the anionic surfactant and the cationic surfactant within the aforementioned range.
<Development>
The above-described photoresist developer of the present invention can be suitably used for developing a thick photoresist layer having a thickness of 3 μm or more, preferably 5 to 100 μm, and most preferably 10 to 100 μm. That is, even when applied to the development of such a thick photoresist layer, there is no scum generation and a fine resist pattern can be formed with high precision. Therefore, the connection terminals such as bumps can be effectively manufactured by plating.

  Further, the photoresist developer of the present invention can be applied to any conventionally known positive photoresist or negative photoresist. A positive photoresist is a resin composition that is made insoluble by adding an alkali-insoluble photosensitizer such as naphthoquinonediazide to an alkali-soluble resin such as a novolak-type phenolic resin. As a result, the exposed portion becomes alkali-soluble, the exposed portion is eluted and removed by the developer, and a resist pattern is formed by the unexposed portion. The negative photoresist is composed of a resin composition in which a crosslinking agent such as a polyhydric phenol is blended with the alkali-soluble resin as described above, and the exposed part becomes alkali-insoluble due to a crosslinking reaction by light irradiation, and the unexposed part Is eluted and removed in the developing solution, and the resist pattern is removed by the exposed portion.

  Furthermore, the developer of the present invention is most effectively applied to the development of a chemically amplified photoresist. That is, a chemically amplified photoresist is obtained by blending a photosensitive resin composition with a photoacid generator (usually 0.1 to 5 parts by mass per 100 parts by mass of a resin component), and depends on an acid generated by light. Since modification of the photosensitive resin (alkali solubilization or alkali insolubilization) is performed, the modification is performed with a short exposure time and high sensitivity, which is suitable for forming a fine resist pattern.

  As such a chemically amplified photoresist, those known per se are used.

  For example, in a positive chemically amplified photoresist, as a photosensitive resin, a protective group that decomposes an alkali-soluble group of an alkali-soluble resin with an acid (for example, a tertiary alkyl group such as t-butyl ester or an acetal such as ethoxy ester). Typically, a resin protected with an ester group or the like is used, and a resin containing a photoacid generator is typically used, and the protecting group is eliminated by the light irradiation and the acid generated by the light irradiation to become alkali-soluble. Examples of the alkali-soluble resin having an alkali-soluble group as described above include, but are not limited to, novolak-type phenol resin, acrylic resin, fluorine-based resin, polyhydroxystyrene, and maleic anhydride-modified norbornene resin. Representative. As photoacid generators, sulfonium salts, phosphonium salts, diarylhalonium salts, diazonium salts, diazomethanes, triazines, and the like are known.

  The negative chemically amplified resist is obtained by adding the above-mentioned photoacid generator to the above-mentioned normal negative photoresist, and the alkali-soluble resin is formed by the light irradiation and the acid generated by the light irradiation. It crosslinks and becomes insoluble in alkali.

  As described above, the developer of the present invention can be applied to both development of positive and negative photoresists, but effectively suppresses dissolution of resist components from unexposed areas into the developer. Since the resist pattern has a particularly high effect of suppressing the deterioration of the shape of the resist pattern, it is particularly suitable for developing a positive type photoresist, and particularly suitable for developing a positive type chemically amplified photoresist.

  Development using the photoresist developer of the present invention can be carried out according to a known method. That is, the above-mentioned various photoresist-containing coating solutions are applied to a predetermined substrate surface and dried to form the above-described thick-film photoresist layer, and then exposed in a predetermined pattern through a mask, After the exposure, development is performed using the photoresist developer of the present invention. After the development, the developer containing the resist component eluted with a rinse solution is washed away and dried to obtain the desired positive type or A negative resist pattern is formed on the substrate surface.

  In the above development, exposure is performed by irradiating light having a wavelength corresponding to the photosensitivity of the used photoresist. In particular, when a fine resist pattern is formed, light having a short wavelength such as excimer laser light is irradiated, but exposure by electron beam or X-ray irradiation is also possible depending on the type of photoresist. When a chemically amplified photoresist is used, it is heated to a temperature of 70 to 110 ° C. as necessary in order to promote acid generation. This heating is performed after exposure, and the heating time is usually about 1 to 10 minutes.

  For the development after exposure, a known method such as a dipping method, a paddle development method, or a spray development method can be employed without any particular limitation. For example, the dipping method is a developing method in which a substrate such as a silicon wafer on which a photoresist layer is formed is dipped in a developer for a certain period of time and then dipped in pure water and dried. The paddle development method is a development method in which a developer is dropped onto the photoresist layer surface, left standing for a certain period of time, then washed with pure water and dried. The spray development method is a photoresist layer surface. This is a developing method in which a developer is sprayed onto the substrate, and then washed with pure water and dried.

  After the positive or negative resist pattern is formed as described above, an etching process and a plating process are performed as in conventional photolithography, and bumps and the like are connected to the recesses (pattern gaps) of the resist pattern. Terminals are formed, and finally the photoresist forming the resist pattern is removed.

EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to an Example.
<Production Examples 1 to 9 and Comparative Production Examples 1 to 4>
A 20.0 mass% TMAH aqueous solution (trade name SD-20, manufactured by Tokuyama Corporation) was diluted with ultrapure water to prepare a 3.0 mass% TMAH aqueous solution, and various surfactants were added to the obtained aqueous solution. Are added in the amounts shown in Table 1 (Production Examples 1 to 4), Table 2 (Production Examples 5 to 9), and Table 3 (Comparative Production Examples 1 to 4). A resist developer was prepared.

  In Comparative Production Example 1, neither an anionic surfactant nor a cationic surfactant is used. The anionic surfactant was treated with a cation exchange resin, and the total concentration of sodium ions and potassium ions in the anionic surfactant (100% equivalent) was adjusted to 10 ppm or less. Tables 1, 2 and 3 also show the pH, sodium ion and potassium ion concentrations of these various developers.

<Examples 1-9 and Comparative Examples 1-5>
The following two types of photoresists were prepared as positive photoresists for thick film formation.

Novolak-diazonaphthoquinone positive resist:
Resin component: Novolac-type phenolic resin (alkali-soluble resin)
Photosensitizer; diazonaphthoquinone chemically amplified resist (positive type):
Prepare a photoresist 4-inch silicon wafer containing polymethacrylic acid-based resin in which carboxylic acid is protected with an ester group and polyhydroxystyrene as a resin component as an alkali-soluble resin, and an acid generator. The wafer surface was cleaned at a volume ratio of 4: 1). Then, it was baked on a hot plate at 200 ° C. for 60 seconds.

  Next, using the spinner, the positive photoresist was applied to the silicon wafer to form a positive photoresist layer having a thickness of 3.5 μm.

  Various developer solutions prepared in Production Examples 1 to 9 and Comparative Production Examples 1 to 4 after irradiation with g, h and i rays having a wavelength of 300 to 500 μm through the mask pattern to the obtained positive photoresist layer. Then, paddle development was performed at 23 ° C. for 8 minutes, and a resist pattern (contact hole pattern) having a pattern gap width of 20 μm was obtained.

  For this resist pattern, the presence or absence of scum and the pattern shape were evaluated using a scanning electron microscope (SEM). The results are shown in Table 4.

  The evaluation criteria are as follows.

Presence or absence of scum;
○: No scum is generated.

        X: Scum is present.

Pattern shape;
A: Very good.

That is, the pattern dimension error is within 5% of the intersection of the target dimensions, and the development
The side wall of the subsequent pattern recess (gap) is upright. (Top and side of the pattern
The intersecting part of the wall is almost perpendicular, and there is no taper at the bottom of the concave side wall. )
○: Good.

That is, the pattern dimension error is less than 10% of the intersection of the target dimensions, and the development
The side walls of the recesses of the later pattern are upright.

        X: It is bad.

That is, the pattern dimension error is 10% or more of the intersection of the target dimensions, and the development
The side wall of the concave portion of the later pattern is not upright. (Intersection of the upper surface and side wall of the pattern
The difference is rounded, and the lower part of the recess side wall is tapered. )

<Examples 10 to 18 and Comparative Examples 6 to 9
Except that the film thickness of the positive photoresist to be applied was changed to 20.0 μm, the development was carried out using various developing solutions in the same manner as in the above-mentioned examples and comparative examples, and the contact having a pattern gap width of 20 μm A hole pattern was obtained and the same evaluation was performed. The results are shown in Table 5.

  As shown in the experimental results of Tables 4 and 5, when development was performed using the developer of the present invention (Examples 1 to 18), in the case where the thickness of the photoresist layer was 3 μm or more, usually No scum was generated and the pattern shape was good when the photoresist layer was formed of any of the above photoresists and chemically amplified photoresists.

Claims (7)

In a photoresist developer comprising an aqueous solution of a quaternary ammonium compound,
The aqueous solution of the quaternary ammonium compound contains an anionic surfactant and a cationic surfactant,
The quaternary ammonium compound is a strongly basic quaternary lower alkyl ammonium hydroxide,
The anionic surfactant has the following formula (1):

(In the formula, p is an integer of 1 to 3, m is an integer of 5 to 30, R ¹ is a hydrogen atom or a methyl group, and R ² is a hydrogen atom or a carbon number of 1 to 4. A is an alkylene group having 2 to 4 carbon atoms, and a plurality of divalent groups AO may be the same or different from each other, and M is a hydrogen atom or an ammonium ion. Is)
A compound represented by
When the total mass of the photoresist developer is 100% by mass, the anionic surfactant is contained at a concentration of 0.1 to 5% by mass and the cationic surfactant is contained at a concentration of 0.01 to 2% by mass. A photoresist developer. The cationic surfactant is represented by the following formula (2):

(Wherein R ³ , R ⁴ and R ⁵ are each a hydrogen atom or an organic group having 1 to 20 carbon atoms, and X is OH, Cl, Br or I)
The photoresist developer according to claim 1, which is a quaternary ammonium salt represented by the formula:   The photoresist developer according to claim 1, wherein the anionic surfactant has a molecular weight of 600 to 1,500.   The photoresist developer according to claim 1, wherein the total concentration of sodium ions and potassium ions is suppressed to 500 ppb or less.   A photoresist developing method, wherein the photoresist developer according to claim 1 is used for developing an exposed thick film resist layer having a thickness of 3 μm to 100 μm.   The photoresist developing method according to claim 5, wherein the thick resist layer is a chemically amplified resist layer.   The photoresist development method according to claim 5, wherein the thick film resist layer is a novolak-diazonaphthoquinone type resist.