KR101084454B1 - Photoresist developing solution - Google Patents

Abstract

This invention provides the developing solution which can be used suitably for image development of the thick film resist containing a chemically amplified resist. The photoresist developer of the present invention is a photoresist developer including an aqueous solution of a quaternary ammonium compound containing an anionic surfactant and a cationic surfactant, wherein the mass of the entire photoresist developer is represented by the following general formula (1): It is characterized by containing 0.1-5 mass% of anionic surfactant and 0.01-2 mass% of cationic surfactant.

<Formula 1>

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, A is an alkylene group having 1 to 4 carbon atoms, and in one molecule, AO is the same or different from each other; Combinations, p is an integer from 1 to 3, m is an integer from 5 to 30, M is a hydrogen atom or ammonium ion)

Photoresist developer, chemically amplified resist, quaternary ammonium compound

Description

Photoresist Developer {PHOTORESIST DEVELOPING SOLUTION}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to novel photoresist developers for use in the manufacture of semiconductor devices, flat panel displays (FPDs), circuit boards, magnetic heads, and the like, and in particular, thick film photos including chemical amplification resists and the like. The present invention relates to a photoresist developer that can be suitably used for developing resists.

In a wide range of fields, including the manufacture of semiconductor integrated circuits such as LSIs, the manufacturing of display surfaces of FPDs, and the manufacture of circuit boards such as magnetic heads, the importance of precision processing techniques for forming fine devices or fine processing is increasing. . In such a precision processing technique, a processing means called photofabrication is mainstream. With photofabrication, the photosensitive resin composition called photoresist is apply | coated to the surface of a to-be-processed object, a coating film (resist layer) is formed, and it exposes, and patternes the coating film after exposure with a developing solution (formation of a resist pattern), and masks this. As an electroforming (specifically, chemical etching, electrolytic etching, electroplating, or a combination thereof), a technique for forming various elements, wiring patterns, and the like is used for manufacturing various precision components such as semiconductor packages.

Alkali aqueous solution is used as the developing solution in the above-mentioned photofabrication. However, when metal alkali is contained in such aqueous alkali solution, it adversely affects the electrical characteristics, such as a semiconductor package obtained. Therefore, aqueous solutions of organic quaternary ammonium compounds, such as alkali aqueous solution which does not contain a metal ion, for example, tetramethylammonium hydroxide (henceforth, TMAH) may be used widely as a developing solution.

At the time of patterning the resist layer using the developer, it is necessary to prevent the resist component eluted in the developer from re-adhering to the gap portion of the resist pattern in order to form a resist pattern that matches the exposure pattern with high precision. . Although the reattached resist component is called a scum, generation | occurrence | production of a scum will cause the adhesiveness of a board | substrate and a conductor to fall in the plating process of a subsequent conductor. The occurrence of such scums is prevented, and as a developer capable of forming a high-precision resist pattern, a number of surfactants have been added to aqueous solutions of quaternary ammonium compounds.

For example, Patent Literatures 1 and 2 propose developing solutions containing a tetramethylammonium hydroxide aqueous solution to which a nonionic surfactant and a cationic surfactant are added. In addition, Patent Document 3 proposes a developer containing an aqueous solution of a quaternary ammonium compound to which an anionic surfactant is added.

On the other hand, in recent years, the high-density mounting technology of a semiconductor package is progressing with downsizing of an electronic device. For example, in order to package an LSI, the multi-pin thin film mounting method which installs a protrusion electrode as a connection terminal in the board | substrate surface is applied, have. In this multi-pin thin film mounting method, a connection terminal (protrusion electrode) including bumps protruding from the substrate surface or a connection terminal including a post called a metal post protruding from the substrate and solder balls formed on the posts are used. The packaging such as LSI is performed. Such bumps and metal posts form a photoresist layer of a thick film having a thickness of 3 µm or more, in particular 8 µm or more, on the substrate surface, and a photoresist layer has a resist pattern having a line width of 5 µm or more by exposure and development, followed by a resist gap. It is manufactured by embedding a conductor such as copper in a portion (not covered with the resist and exposing the substrate surface portion) by plating or the like, and finally removing the resist pattern around it.

The photoresist developer 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 exhibits an excellent effect. However, as the thickness of the photoresist layer becomes thicker, the amount of the resist component dissolved in the developer increases, which causes problems such as increased scum, and it becomes difficult to form a fine resist pattern with high precision. For example, in the developing solution described above, when developing a photoresist layer having a thickness of 3 µm or more, scum is increased, and therefore, development characteristics are required to be improved.

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

Patent Document 1: Japanese Patent Application Laid-Open No. 6-3549

Patent Document 2: Japanese Patent Laid-Open No. 2002-169299

Patent Document 3: Japanese Patent No. 2589408

Patent Document 4: International Publication No. WO06 / 134902

<Start of invention>

Problems to be Solved by the Invention

However, patterning of a photoresist layer irradiates light, such as an ultraviolet-ray, in a predetermined pattern (exposure), and modifies the base resin (photosensitive resin) in the photoresist layer in an exposed part (alkali of photosensitive resin), for example. Solubilization or alkali insolubilization), followed by eluting and removing the resist component of the exposed portion or the unexposed portion with a developer, thereby forming a positive or negative resist pattern in accordance with the exposure pattern. Recently, there have been attempts to increase the productivity and dimensional accuracy by shortening the exposure time even in a thick film photoresist layer, and in the case of using a chemically amplified resist that can perform fine processing with higher sensitivity than a novolak-diazonaphthoquinone type resist. Is increasing. In the chemically amplified resist, a photoacid generator is added in addition to the photosensitive resin, and an acid generated by light irradiation functions as a catalyst, and modification of the photosensitive resin (alkali solubilization or alkali insolubilization) is promoted by heating after exposure. In the thick photoresist layer formed using such a chemically amplified resist, the exposure time can be shortened, the productivity can be improved, and the sensitivity is high, so that a resist pattern with high dimensional accuracy can be formed.

However, according to the studies by the present inventors, in the developer proposed in Patent Document 4, sufficient effects are not exerted on the thick photoresist layer formed by using the chemically amplified resist, and shape defects of the resist pattern are likely to occur. There is a flaw, and further improvement of development characteristics is required.

Accordingly, an object of the present invention is to form a photoresist layer having a thickness of 3 µm or more, in particular, a chemically amplified resist, so that the occurrence of scum is effectively prevented even when developing the photoresist layer of a thick film, and the resist pattern has high dimensional accuracy. The present invention provides a photoresist developer capable of forming a film.

Means for solving the problem

MEANS TO SOLVE THE PROBLEM This inventor repeated earnest research in order to achieve the said objective. As a result, the inventors discovered that a photoresist developer in which a specific anionic surfactant and a cationic surfactant were added to an aqueous solution of a quaternary ammonium compound could solve the above problems, and came to complete the present invention.

According to the present invention, in a photoresist developer containing an aqueous solution of a quaternary ammonium compound,

The aqueous solution of the quaternary ammonium compound includes an anionic surfactant and a cationic surfactant,

The quaternary ammonium compound is a strong basic quaternary lower alkyl ammonium hydroxide,

The anionic surfactant is a compound represented by the following formula (1),

When the mass of the whole photoresist developing solution is 100 mass%, the photoresist developing solution contains 0.1-5 mass% of said anionic surfactant and 0.01-2 mass% of said cationic surfactant. This is provided.

(Wherein p is an integer of 1 to 3,

m is an integer from 5 to 30,

R ¹ is a hydrogen atom or a methyl group,

R ² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,

A is an alkylene group having 2 to 4 carbon atoms, and a plurality of divalent groups AO present may be the same or different from each other,

M is a hydrogen atom or ammonium ion)

In the photoresist developer of the present invention,

(1) the cationic surfactant is a quaternary ammonium salt represented by the following formula (2),

(2) the anionic surfactant having 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

This is preferred.

(Wherein, R ³ , R ⁴ and R ⁵ are each a hydrogen atom or an organic group having 1 to 20 carbon atoms,

X is OH, Cl, Br or I)

According to the present invention, there is provided a photoresist developing method, wherein the photoresist developer is used for developing an exposed thick film resist layer having a thickness of 3 to 100 µm.

Effect of the Invention

When the photoresist developer of the present invention is used, even when a thick film photoresist layer having a film thickness of 3 µm or more, in particular 10 µm or more, no scum is generated, and a good pattern shape can be maintained. In particular, even when the thick film photoresist layer contains a chemically amplified resist, scum does not occur, and a favorable resist pattern with high dimensional accuracy can be formed, and therefore, its industrial utility value is very high.

In the present invention, when the specific anionic surfactant and the cationic surfactant represented by the formula (1) is blended in the aqueous solution of the quaternary lower alkyl ammonium hydroxide, the above-described effects occur, and the present inventors It is estimated as follows.

That is, an anionic surfactant adheres to the resist surface at the time of development, and this surfactant effectively prevents the generation of scum (i.e., adhesion of the resist component dissolved in the developer), thereby effectively maintaining the shape of the resist pattern. On the other hand, the cationic surfactant exhibits a function of preventing excessive elution of the resist component into the developer and preventing shape deterioration of the resist pattern due to erosion of the developer. It is thought that it becomes possible to form a resist pattern. For example, as understood from the experimental results of the examples described later, although the generation of scum is suppressed in the developer (Comparative Example 2) in which only anionic surfactant is blended and no cationic surfactant is blended, resist is prevented. This is because the pattern shape cannot be maintained and the anionic surfactant and the cationic surfactant are blended, but the development of scum cannot be prevented in the developer (Comparative Example 3) having a small amount of the anionic surfactant. .

Best Mode for Carrying Out the Invention

In the photoresist developer of the present invention, a specific anionic surfactant and a cationic surfactant are added 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, the aqueous solution of the quaternary ammonium compound to which various surfactants are added is strongly basic, dissolves an alkali soluble substance in the photoresist layer after exposure, and is a main component of the photoresist developer. This aqueous solution contains substantially no 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 is conventionally known as a component of a photoresist developer, and is specifically 1 in view of high solubility in a resist component after exposure and easy removal of the developer by a cleaning solution (rinse solution) after development. A strong basic quaternary lower alkyl ammonium hydroxide having a pH of 25% in an aqueous solution of mass% concentration of 12 or more is used.

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

These quaternary ammonium hydroxides are broadly divided into tetra lower alkyl ammonium hydroxides and tri lower alkylated (hydroxy lower alkyl) ammonium hydroxides.

Examples of tetra lower alkyl ammonium hydroxide include tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, trimethylethylammonium hydroxide, and trilower alkyl (hydroxy lower). Examples of alkyl) ammonium hydroxides include trimethyl (2-hydroxyethyl) ammonium hydroxide, triethyl (2-hydroxyethyl) ammonium hydroxide, tripropyl (2-hydroxyethyl) ammonium hydroxide, trimethyl (1-hydroxypropyl) ammonium hydroxide, etc. are mentioned. These quaternary lower alkyl ammonium hydroxides are used individually or in combination of two or more in the form of an aqueous solution. Particularly preferred among the above are TMAH and trimethyl (2-hydroxyethyl) ammonium hydroxide. This is because these are highly basic and highly water-soluble, and the aqueous solution thereof can not only easily elute the resist component after exposure, but also can be easily washed and removed by the rinse liquid after exposure.

In addition, although the density | concentration of the above-mentioned quaternary lower alkylammonium hydroxide differs in the optimal density | concentration according to the kind, it cannot be uniformly limited, but generally the total amount of photoresist developing solution is 0.1-10 mass as 100 mass%. %, Especially 1-5 mass%. When the concentration of the quaternary lower alkyl ammonium hydroxide satisfies the above range, the alkali solubles which need to be removed from the photoresist layer after exposure can be selectively eluted and removed, and high-precision patterning becomes possible.

<Anionic Surfactants>

As the anionic surfactant added to the aqueous solution of the quaternary lower alkyl ammonium hydroxide in the present invention, a compound represented by the following formula (1) is used.

<Formula 1>

(Wherein p is an integer of 1 to 3,

m is an integer from 5 to 30,

R ¹ is a hydrogen atom or a methyl group,

R ² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,

A is an alkylene group having 2 to 4 carbon atoms, may be branched, and a plurality of divalent groups AO present may be the same or different from each other,

M is a hydrogen atom or ammonium ion)

As mentioned above, although such anionic surfactant is considered to function to suppress scum generation, especially the compound in the range of 600-1,500 molecular weight contributes to suppression of scum generation, and it is used preferably. When the molecular weight is too small, it is considered that the surfactant activity is lowered, and the effect of maintaining the pattern shape tends to be lowered. Moreover, even when the molecular weight is too large, since the ratio of the functional group (S0 ₃ M group) in a molecule | numerator falls, the ratio of the functional group in a photoresist developing solution will also fall, the surface activity effect will become low, and the effect of suppressing scum generation is sufficient. Instead, it is estimated that the effect of maintaining the pattern shape is lowered. As an example of the anionic surfactant whose molecular weight is in the said range, the following compound is mentioned.

The anionic surfactant as described above may be used alone, or may be used by mixing two or more kinds.

In the present invention, the anionic surfactant is blended in an amount of 0.1 to 5% by mass, preferably 0.5 to 5.0% by mass, most preferably 1.0 to 5.0% by mass, as the mass of the entire photoresist developer as 100 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 is reduced. For example, a resist component elutes from the unexposed part of positive type resist, and the deterioration of a resist pattern shape becomes large.

In the photoresist developer of the present invention described later, it is preferable that the content of sodium ions and potassium ions be suppressed to a certain amount or less, so that the alkali metal ions contained in the anionic surfactant described above are as small as possible. That is, although the above-mentioned anionic surfactant may contain an alkali metal ion (sodium ion and potassium ion) as an unavoidable impurity in its manufacture, it is preferable to use that whose alkali metal ion is suppressed to 10 ppm or less. Do. The reduction of the amount of alkali metal ions can be easily carried out by purification in contact with a hydrogen cation exchange resin or the like.

<Cationic surfactant>

In the present invention, not only the above-mentioned anionic surfactants but also cationic surfactants are used, and the use of such cationic surfactants causes, for example, an excessive resist component to be eluted in the developer, resulting in deterioration of the pattern shape of the resist. Can be effectively prevented. That is, in the developing solution to which the cationic surfactant is not mix | blended, the photoresist component elutes in the developing solution from the area | region which does not need to be removed by image development in the photoresist layer after exposure, and the shape of a resist pattern deteriorates.

In the present invention, such a cationic surfactant can be used a commercially known known one, and representative examples thereof include higher alkyltrimethylammonium hydroxide or ammonium salt thereof, dialkyldimethylammonium hydroxide or ammonium salt thereof (at least one of dialkyl is higher Alkyl), benzylimidazolinium hydroxide or imidazolinium salt thereof, alkylbenzyldimethylammonium hydroxide or ammonium salt thereof, benzylpyridinium hydroxide or pyridinium salt thereof, benzyltrialkylammonium hydroxide or ammonium salt thereof, alkylpyridinium hydroxide or Pyridinium salt, polyoxyethylene alkylbenzyl ammonium hydroxide or its ammonium salt, polyoxyethylene alkyl trialkylammonium hydroxide or its ammonium salt, etc. are mentioned, These cationic surfactant may be used individually by 1 type, and 2 types It may be used in the combination.

In addition, higher alkyl means an alkyl group having 5 or more carbon atoms.

In the developing solution of the present invention, a cationic surfactant represented by the following chemical formula is particularly preferable from the viewpoint of having a high retention effect of the resist pattern shape in combination with the anionic surfactant described above.

In said formula, R <^3> , R <^4> and R <^5> are a hydrogen atom or an organic group of 1-20 carbon atoms, respectively, The said organic group may also contain an ester bond, an ether bond, or an amide bond.

R ⁶ is a pyridinium group or an imidazolinium group, R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are alkyl groups having 1 to 20 carbon atoms, at least one of them is a higher alkyl group having 5 or more carbon atoms, 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.

In addition, q represents the integer of 5-20, X represents OH, Cl, Br, or I.

Further preferred among the cationic surfactants represented by the above formulas are the following compounds.

Wherein X represents OH, Cl, Br or I

Among the various cationic surfactants described above, those represented by the following general formula (2) may be mentioned as optimum ones from the viewpoints of exhibiting the most excellent effect and easy availability (manufacturing).

<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,

X is OH, Cl, Br or I)

In addition, the organic group represented by R <^3> , R <^4> and R <^5> in the said general formula may also contain an ester bond, an ether bond, or an amide bond.

Among these optimal cationic surfactants, the most readily available are the following compounds.

(X is OH, Cl, Br or I)

The compounding quantity of the said cationic surfactant is 0.01-2.0 mass%, especially 0.03-1.0 mass% as mass mass of the whole photoresist developing solution as 100 mass%. When the amount is less than the above range, the effect of suppressing the resist pattern shape deterioration is less. When the amount is more than the above range, the developing speed is slowed, and the practicality is impaired.

It is preferable to use the above-mentioned cationic surfactant in the range which the mass ratio (anionic surfactant: cationic surfactant) with said anionic surfactant becomes 10-100: 1. By using both components at such mass ratios, the effect of maintaining the resist pattern shape by preventing scum generation of the anionic surfactant and the prevention of shape deterioration by excessive dissolution of the resist component of the cationic surfactant is most balanced. It is expressed effectively.

<Photoresist Developer>

Although the photoresist developer of this invention is obtained by mix | blending the anionic surfactant and cationic surfactant mentioned above with the aqueous solution of a quaternary lower alkyl ammonium hydroxide, it is conventional in addition to these surfactant in the range which does not impair the effect of this invention. Known additives used in the developer, for example, wetting agents, stabilizers, dissolution aids and the like may also be appropriately blended.

The total concentration of sodium ions and potassium ions in the photoresist developer is preferably suppressed to 500 ppb or less. When the amount of these alkali metal ions is larger than the above range, not only the electrical characteristics of the finally obtained semiconductor package or the like may be impaired, but also the resist component is easily eluted in the developer, and the pattern shape may be deteriorated. Because there is. 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.

Moreover, the pH of the photoresist developer of this invention is higher than 12.5, and it is especially preferable that it is 13 or more. By using such a strong base photoresist developer, the developing speed is high and stable development can be performed. PH adjustment of a photoresist developing solution can be implement | achieved by adjusting the density | concentration of the above-mentioned quaternary lower alkyl ammonium hydroxide, anionic surfactant, and cationic surfactant within the above-mentioned range.

<Phenomena>

The photoresist developer of the present invention described above can be suitably used for the development of 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 the photoresist layer of such a thick film, no scum is generated and a fine resist pattern can be formed with high precision. For example, in the concave portion of the resist removing portion, the sidewalls are prevented from tapering and the upright state Since it is formed with, connection terminals such as bumps can be manufactured effectively by plating.

In addition, the photoresist developer of the present invention can be applied to any of a conventionally known positive photoresist and negative photoresist. The positive photoresist is a resin composition obtained by mixing alkali insoluble photosensitizers such as naphthoquinone diazide with alkali-soluble resins such as novolak-type phenol resins and making them alkali insoluble. An exposure part becomes alkali-soluble, an exposure part elutes and removes with a developing solution, and a resist pattern is formed by an unexposed part. Moreover, the negative photoresist contains the resin composition which mix | blended crosslinking agents, such as polyhydric phenol, with alkali-soluble resin as mentioned above, an exposure part becomes alkali insoluble by the crosslinking reaction by light irradiation, and an unexposed part is a developing solution. It means that the resist pattern is eluted and removed to form a resist pattern by the exposed portion.

In addition, the developer of the present invention is most effectively applied to the development of chemically amplified photoresists. That is, the chemically amplified photoresist is obtained by mixing a photoacid generator (typically 0.1 to 5 parts by mass with respect to 100 parts by mass of the resin component) in the photosensitive resin composition, and using a photosensitive resin (alkali solubilizing or Alkali insolubilization) is carried out, so that not only the exposure time is short but also highly sensitive, it is suitable for the formation of a fine resist pattern.

As such chemically amplified photoresist, a known one per se is used.

For example, in a positive chemically amplified photoresist, as a photosensitive resin, the protecting group which decomposes the alkali-soluble group which alkali-soluble resin which an alkali-soluble resin has with an acid (for example, tertiary alkyl groups, such as t-butyl ester, ethoxy ester, etc.) The resin protected by an acetal ester group etc.) is used, and it is typical to mix | blend a photo-acid generator with this, and a protecting group leaves | releases by the acid generate | occur | produced by light irradiation and light irradiation, and becomes alkali-soluble. As alkali-soluble resin which has alkali-soluble group as mentioned above, it is not limited to this, A novolak-type phenol resin, an acrylic resin, a fluorine-type resin, polyhydroxy styrene, maleic anhydride modified norbornene resin etc. are typical. As the photoacid generator, sulfonium salts, phosphonium salts, diarylhalonium salts, diazonium salts, diazomethanes, triazines and the like are known.

The negative chemically amplified resist is obtained by adding a photoacid generator as described above to the conventional negative photoresist described above, and alkali-soluble resin is crosslinked by an acid generated by light irradiation and light irradiation to give alkali. It becomes insoluble.

As described above, the developer of the present invention can be applied to any development of positive and negative photoresists, but the elution of the resist component from the unexposed portion into the developer is effectively suppressed, and the shape deterioration suppression effect of the resist pattern is effectively suppressed. Since is particularly high, it is particularly preferable for the development of a positive photoresist, and most particularly for the development of a positive chemically amplified photoresist.

The development using the photoresist developer of the present invention can be performed according to a known method. That is, the coating liquid containing the various photoresist mentioned above is apply | coated to a predetermined board | substrate surface, and it is made to dry, the photoresist layer of the thick film mentioned above is formed, and then it exposes in a predetermined pattern through a mask, and after this exposure, this invention After the development is carried out using a photoresist developer, the developer containing the resist component eluted using the rinse solution after development is washed and dried to form a target positive or negative resist pattern on the substrate surface. .

Exposure at the time of the said image development is performed by irradiating the light of the wavelength according to the optical sensitivity which the used photoresist has. In particular, in the case of forming a fine resist pattern, light of short wavelength such as excimer laser light is irradiated, but exposure by electron beam or X-ray irradiation may be possible depending on the type of photoresist. In addition, when a chemically amplified photoresist is used, it is heated to a temperature of 70 to 110 ° C as necessary to promote the generation of acid. This heating is performed after exposure, and the heating time is about 1 to 10 minutes normally.

The image development after exposure can use well-known methods, such as an immersion method, a puddle image development method, and a spray image development method, without particular limitation. For example, the immersion method is a developing method in which a substrate such as a silicon wafer on which a photoresist layer is formed is immersed in a developing solution for a predetermined time, and then immersed in pure water and dried. The puddle developing method is a developing method in which a developer is dropped on a surface of a photoresist layer and left to stand for a predetermined time, followed by washing with pure water and drying. The spray developing method is sprayed with pure water after spraying a developing solution on a surface of a photoresist layer. It is a developing method to dry by.

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

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to Examples.

<Production Examples 1 to 9 and Comparative Production Examples 1 to 4>

A 20.0 mass% aqueous TMAH solution (trade name SD-20, manufactured by Tokuyama Co., Ltd.) was diluted with ultrapure water to prepare a TMAH aqueous solution having a concentration of 3.0 mass%, and various surfactants were prepared in Table 1 (Preparation Examples 1 to 2). 4), the amounts shown in Tables 2 (Manufacturing Examples 5 to 9) and Table 3 (Comparative Production Examples 1 to 4) were added to prepare various photoresist developer solutions.

In Comparative Production Example 1, none of the anionic surfactant and the cationic surfactant was 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 and used. Tables 1, 2 and 3 also show the pH, sodium ions and potassium ions concentrations of these various developer solutions.

<Examples 1 to 9 and Comparative Examples 1 to 5>

As the positive photoresist for forming a thick film, the following two types of photoresists were prepared.

Novolac-diazonaphthoquinone-based positive resists:

Resin component; Novolak-type phenolic resin (alkali-soluble resin)

Photosensitizers; Diazonaphthoquinone

Chemically Amplified Resist (Positive Type):

Photoresist comprising an acid generator and containing polyhydroxy styrene as a resin component as polymethacrylic acid-based resin protecting carboxylic acid with ester group and alkali-soluble resin

A 4 inch silicon wafer was prepared and the wafer surface was cleaned with sulfuric acid-hydrogen peroxide (volume ratio 4: 1). Subsequently, firing was performed at 200 ° C. for 60 seconds on a hot plate.

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

After the obtained positive photoresist layer was irradiated with g, h, and i rays having a wavelength of 300 to 500 µm through a mask pattern, development time 8 was performed using various developer solutions prepared in Preparation Examples 1 to 9 and Comparative Preparation Examples 1 to 4. The puddle development was performed at 23 degreeC for the minute, and the resist pattern (contact hole pattern) whose width | variety of a pattern gap part is 20 micrometers was obtained.

About this resist pattern, the presence or absence of scum and a pattern shape were evaluated using the scanning electron microscope (SEM), and the result is shown in Table 4.

In addition, evaluation criteria are as follows.

With or without Scum:

○: no scum occurs.

X: There is a scum.

Pattern shape:

(Double-circle): Very good.

That is, the pattern dimensional error is within 5% of the target dimensional intersection, and the sidewalls of the pattern recesses (gaps) after development are erect (the portions where the upper surface of the pattern and the sidewalls cross are almost right angles, and the recess sidewalls No tapering at the bottom).

(Circle): Good.

That is, the pattern dimension error is less than 10% of the target dimension crossing, and the side wall of the recessed part of the pattern after image development is standing upright.

×: defective.

That is, the pattern dimensional error is 10% or more of the target dimensional intersection, and the sidewalls of the recesses of the pattern after development are not standing upright (the part where the upper surface of the pattern and the sidewalls cross is rounded, and the lower part of the recess sidewalls Is tapered).

<Examples 10 to 18 and Comparative Examples 6 to 9>

Except for setting the film thickness of the positive type photoresist to be applied in the same manner as in the above-described Examples and Comparative Examples, development was carried out using various developing solutions to obtain a contact hole pattern having a width of 20 μm of the pattern gap portion. And the same evaluation was performed. The results are shown in Table 5.

As shown in the experimental results of Table 4 and Table 5, when development was performed using the developer of the present invention (Examples 1 to 18), when the thickness of the photoresist layer was 3 µm or more, conventional photoresist and chemical Even if the photoresist layer was formed by any of the amplification type photoresists, scum was not generated and the pattern shape was good.

Claims (7)

A photoresist developer containing an aqueous solution of a quaternary ammonium compound, The aqueous solution of the quaternary ammonium compound includes an anionic surfactant and a cationic surfactant, The quaternary ammonium compound is a strong basic quaternary lower alkyl ammonium hydroxide, The anionic surfactant is a compound represented by the following formula (1), When the mass of the whole photoresist developing solution is 100 mass%, the photoresist developing solution contains 0.1-5 mass% of said anionic surfactant and 0.01-2 mass% of said cationic surfactant. . <Formula 1>

(Wherein p is an integer of 1 to 3, m is an integer from 5 to 30, R ¹ is a hydrogen atom or a methyl group, R ² is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, and a plurality of divalent groups AO present may be the same or different from each other, M is a hydrogen atom or ammonium ion) The photoresist developer of claim 1, wherein the cationic surfactant is a quaternary ammonium salt represented by the following formula (2). <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, X is OH, Cl, Br or I) 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. The photoresist development method of Claim 1 is used for image development of the exposed thick film resist layer of 3 micrometers-100 micrometers in thickness. 6. The photoresist developing method according to claim 5, wherein the thick film resist layer is a chemically amplified resist layer. The photoresist developing method according to claim 5, wherein the thick film resist layer is a novolak-diazonaphthoquinone type resist.