JP2009244359A - Liquid developer for thick film resist and resist pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid developer for a thick film resist, developing a thick film resist without residue while corrosion of a metal film is restrained. <P>SOLUTION: This liquid developer for a thick film resist contains a basic compound (a) and a polyhydric alcohol (b), wherein the polyhydric alcohol (b) is contained at a concentration equal to or more than 3 mass% and under 20 mass% to the whole quantity of the liquid developer for the thick film resist. Especially it is preferable to select the polyhydric alcohol (b) from glyceline, propylene glycol and ethylene glycol. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thick film resist developer and a method of forming a resist pattern using the developer.

  Photofabrication, which is currently the mainstream of precision microfabrication technology, is the application of a photosensitive resin composition to the surface of a workpiece to form a coating film, which is then patterned by lithography and masked. As a general term for technologies for manufacturing various precision parts such as semiconductor packages by performing chemical forming, electrolytic etching, and / or electroforming mainly composed of electroplating.

  In recent years, with the downsizing of electronic equipment, high-density packaging technology for semiconductor packages has progressed. Based on multi-pin thin film packaging of packages, miniaturization of package size, flip-chip two-dimensional packaging technology, and three-dimensional packaging technology. The packaging density is improved. In such a high-density mounting technique, as connection terminals, for example, protruding electrodes (mounting terminals) such as bumps protruding on the package, or metal posts that connect the rewirings extending from the peripheral terminals on the wafer and the mounting terminals. Are arranged with high accuracy on the substrate.

  There is a thick film photoresist composition (hereinafter referred to as a “thick film resist composition”) as a material used for the above photofabrication. The thick film resist composition forms a thick film resist, and is used, for example, for forming bumps and metal posts by a plating process. For bumps and metal posts, for example, in the manufacture of semiconductor elements and liquid crystal display elements, a thick film resist having a film thickness of about 20 μm is formed on a silicon wafer or glass plate provided with a metal film such as aluminum for electrode circuit formation. Then, exposure is performed through a predetermined mask pattern, development is performed, and a resist pattern is formed by selectively removing (peeling off) a portion where a bump or metal post is to be formed, and this removed portion (non-resist portion) After a conductor such as copper is embedded by plating, it can be formed by removing the surrounding resist pattern.

  In such thick film resist compositions, miscible additives such as additional resins, plasticizers, adhesion aids, stabilizers, colorants, surfactants, etc. for improving the performance of the resist film. Conventional ones have been added. (Patent Document 1).

However, among the additives as described above, when a polyvinyl ether-based additive such as a polyvinyl ether-based plasticizer is added to the thick film resist composition, a general developer used for resist pattern formation However, such a resin component cannot be sufficiently removed, and there is a disadvantage that a residue remains, and there is a demand for improvement thereof.
JP 2004-309777 A

  An object of the present invention is to provide a thick film resist developer that develops a thick film resist containing a polyvinyl ether-based additive without residue.

  The present inventors have found that the above object can be achieved by incorporating a polyhydric alcohol in a specific ratio in a basic resist developer, and have completed the present invention. Specifically, the present invention provides the following.

  The present invention provides, as a first aspect, a thick film resist developer containing a basic compound (a) and a polyhydric alcohol (b), the polyhydric alcohol (b) being developed for the thick film resist. A developer for a thick film resist is provided, which is contained at a concentration of 3% by mass or more and less than 20% by mass relative to the total amount of the solution.

  The present invention provides, as a second aspect, a step of providing a thick film resist, a step of selectively exposing the thick film resist through a mask pattern, and developing the exposed thick film resist as described above. And a step of forming a resist pattern by developing using a liquid.

  According to the present invention, a thick film resist containing a polyvinyl ether-based additive can be developed without residue.

  Hereinafter, although embodiment of this invention is explained in full detail, this invention is not limited to the following embodiment at all.

  The present invention provides, as a first aspect, a thick film resist developer containing a basic compound (a) and a polyhydric alcohol (b), the polyhydric alcohol (b) being developed for the thick film resist. A developer for thick film resist is provided, which is contained at a concentration of 3% by mass or more and less than 20% by mass with respect to the total amount of the solution. The components (a) and (b) are as follows: is there.

(Basic compound (a))
A conventionally well-known basic compound can be used as a basic compound (henceforth (a) component). Examples of such a basic compound include a basic compound containing an alkali metal and an organic base containing no metal ion.

  Examples of the basic compound containing an alkali metal include hydroxides, carbonates, bicarbonates, phosphates, and pyrophosphates of alkali metals such as lithium, sodium, and potassium.

  Examples of organic bases that do not contain metal ions include amines containing primary, secondary, and tertiary amines in which the substituent is linear, branched or cyclic, specifically 1,3-diamino From diaminoalkanes such as propane, arylamines such as 4,4'-diaminodiphenylamine, alkylamines such as N, N'-diaminodialkylamine, 3-5 carbon atoms in the ring skeleton, nitrogen, oxygen, and sulfur Heterocyclic bases having one or two selected heteroatoms, specifically pyrrole, pyrrolidine, pyrrolidone, pyridine, morpholine, pyrazine, piperidine, oxazole, thiazole and the like. Moreover, a quaternary ammonium compound etc. are used. Specific examples thereof include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, trimethyl (2-hydroxyethyl) ammonium hydroxide, triethyl (2-hydroxyethyl) ammonium hydroxide, tripropyl (2-hydroxy). And lower alkyl quaternary ammonium compounds such as ethyl) ammonium hydroxide and trimethyl (1-hydroxypropyl) ammonium hydroxide. Of these organic bases, quaternary ammonium compounds, particularly tetramethylammonium hydroxide, are preferred. These organic bases may be used alone or in combination of two or more.

  The component (a) has an appropriate concentration selected depending on the type of base used and the resist, and is adjusted to a concentration of usually 0.1 to 10% by mass based on the total amount of the developer for thick film resist. It is preferable. Furthermore, it is particularly preferable that the concentration is adjusted to 0.238 to 5.00% by mass.

(Polyhydric alcohol (b))
Examples of the polyhydric alcohol (hereinafter also referred to as the component (b)) include glycerin, propylene glycol, ethylene glycol, and the like. In particular, glycerin is preferable because it has an excellent anticorrosive effect on metals even in a small amount. These polyhydric alcohols may be used alone or in combination of two or more. Moreover, about the compounding quantity, the ratio of 3 mass% or more and less than 20 mass% is preferable based on the developing solution for thick film resists. When the blending amount is 20% by mass or more, the developing speed decreases, and when it is less than 3% by mass, a residue may be generated. By adding the polyhydric alcohol in a proportion of 3% by mass or more and less than 20% by mass based on the total amount of the developer for thick film resist, a residue is generated in the conventional developer, for example, containing a polyvinyl ether-based additive. There is no residue when developing a thick film resist. Moreover, generation | occurrence | production of the residue which arises from the resist containing the additive which has the resin which consists of a polymer of the mass mean molecular weight 150,000 or more which is difficult to melt | dissolve with the conventional developing solution can also be prevented.

  The thick film resist developer of the present invention includes various additive components commonly used in conventional resist developers, such as surfactants, lubricants, wetting agents, stabilizers, and the like within the range in which the object of the present invention is not impaired. A dissolution aid or the like can be appropriately added. Among these, it is preferable to add a surfactant.

(Surfactant (c))
As the surfactant (hereinafter also referred to as “component (c)”), conventionally known ones can be included, but nonionic surfactants such as acetylene alcohol surfactants and polyoxyethylene alkyl ethers are preferred. Of these, acetylene alcohol surfactants are preferred. By blending this nonionic surfactant, the permeability of the thick film resist developer itself can be improved and the wettability can be improved. When a surfactant is blended in the thick film resist developer of the present invention, the blending amount is preferably 50 to 1000 ppm by mass. By setting the blending amount of the nonionic surfactant within the above range, characteristics such as improved wettability can be obtained.

  The developer for a thick film resist of the present invention has an excellent anticorrosion effect and can be developed without corroding the metal film on the substrate on which the metal film is formed. Examples of the metal film include aluminum, copper, tantalum, One made of an alloy of aluminum and copper can be mentioned. In addition, the developer for thick film resist of the present invention has a deposited aluminum film on a transparent conductive film such as an indium oxide film or an ITO film made of an oxide of indium and tin. It is also effective for the formed substrate and does not peel off or rupture the aluminum film.

  Further, the developer according to the present invention can be used for any thick film resist as long as it can be developed using an alkaline aqueous solution, regardless of whether it is a negative type or a positive type. Specifically, a positive resist containing a naphthoquinonediazide compound and a novolak resin, a positive resist containing a compound that generates an acid upon exposure, a compound that decomposes with the acid and increases its solubility in an alkaline aqueous solution, and an alkali-soluble resin Resist, positive resist containing a compound that generates an acid upon exposure and an alkali-soluble resin having a group that decomposes with acid and increases the solubility in an aqueous alkali solution, and a crosslinking reaction between the compound that generates an acid upon exposure and an acid Examples thereof include a negative resist containing a starting crosslinking agent and an alkali-soluble resin.

  Among such thick film resists, the developer of the present invention is preferably used for a film thickness resist containing a polyvinyl ether compound as an additive. Polyvinyl ether compounds are often added to thick film resists as crosslinking agents and plasticizers. Examples of such polyvinyl ether compounds include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,3-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, and trimethylol. Examples include ethane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, and cyclohexanedimethanol divinyl ether. Polyvinyl ether compounds have low reactivity with the base contained in the developer, and thus were difficult to dissolve and peel with conventional developers. However, by adding the component (b), Ether-based additives can be dissolved, peeled off and removed.

(Developer preparation method)
The developer for thick film resist according to the present invention is uniformly mixed with water in various orders, with various additive components such as the basic compound (a), the polyhydric alcohol (b), and the surfactant (c). You can get it.

  The present invention provides, as a second aspect, a step of providing a thick film resist, a step of selectively exposing the thick film resist through a mask pattern, and developing the exposed thick film resist as described above. A resist pattern forming method comprising: developing a resist pattern by using a liquid; and developing a thick film resist according to the present invention in the step of developing the resist pattern. Other than using a liquid, it can be performed by a conventionally known method.

  That is, a resist composition is applied on a support by a known method such as a spin coating method, a roll coating method, a screen printing method, or an applicator method, and then heated (prebaked) to remove the solvent to obtain a desired film thickness. Form a coating film. At this time, although prebaking conditions change with kinds of each component in a composition, a mixture ratio, a coating film thickness, etc., it is usually 70-130 degreeC, Preferably it is 80-120 degreeC, and is about 2 to 60 minutes. . Moreover, the film thickness of the obtained resist film is 1-150 micrometers, Preferably it is 10-150 micrometers, More preferably, it is 20-120 micrometers, More preferably, it is the range of 20-75 micrometers.

The resist film thus obtained is selectively irradiated (exposed) with radiation, for example, ultraviolet rays or visible rays having a wavelength of 300 to 500 nm through a mask having a predetermined pattern. As these radiation sources, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, an argon gas laser, or the like can be used. Here, the radiation means ultraviolet rays, visible rays, far ultraviolet rays, X-rays, electron beams, and the like. The amount of radiation irradiation varies depending on the type of each component in the composition, the blending amount, the film thickness of the coating film, and the like, but is, for example, 100 to 2000 mJ / cm ² when using an ultrahigh pressure mercury lamp. And, if necessary, when a chemically amplified resist composition is used, after the exposure, it is heated using a known method to promote the generation and diffusion of acid, so that the exposed portion of the resist film is dissolved in alkali. Change sex.

  Next, by using the thick film resist developer of the present invention, unnecessary portions are dissolved and removed to obtain a predetermined resist pattern. The development time varies depending on the type of each component of the resist composition, the blending ratio, and the dry film thickness of the resist composition, but is usually 1 to 30 minutes. Further, the developing method may be any of a liquid piling method, a dipping method, a paddle method, a spray developing method, and the like. After development, washing with running water is preferably performed for 30 to 90 seconds and dried using an air gun, an oven, or the like.

  Then, a connection terminal such as a metal post or a bump is formed by embedding a conductor such as metal in the non-resist portion (portion removed by the developer) of the resist pattern thus obtained, for example, by plating or the like. be able to. The plating method is not particularly limited, and various conventionally known methods can be employed. As the plating solution, solder plating or copper plating solution is particularly preferably used. The remaining resist pattern is finally removed using a stripping solution or the like according to a conventional method.

  The invention is illustrated in detail by the following examples. However, this example illustrates the invention and is not intended to limit the scope of the invention.

Example 1
Tetramethylammonium hydroxide (2.8% by mass), glycerin (3.5% by mass) and pure water (93.7% by mass) were uniformly mixed to prepare a developer.

(Examples 2 and 3)
A developer was prepared in the same manner as in Example 1 except that the amount of glycerin added was changed as shown in Table 1.

(Comparative Example 1)
A developing solution was prepared by uniformly mixing 2.8% by mass of tetramethylammonium hydroxide and 97.2% by mass of pure water.

(Comparative Example 2)
Tetramethylammonium hydroxide 2.8% by mass and pure water 97.2% by mass (trade name NMD-W, manufactured by Tokyo Ohka Kogyo Co., Ltd.) were used.

(Developability test)
A resist containing a polyvinyl ether plasticizer (trade name: PMER P-LA900PM, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied onto a gold sputtered silicon substrate using a spinner, pre-baked at 110 ° C. for 6 minutes, and a film thickness of 20 μm. A resist film was formed. Further, this resist was selectively exposed with an irradiation amount of 2000 mJ / cm ² using an Ultratech Prisma ghi stepper (manufactured by Ultratech). Next, it was immersed in the developers described in Examples 1 to 3 and Comparative Examples 1 and 2 for 6 minutes, and the presence or absence of a residue was visually observed. The results are shown in Table 1. Here, the numerical value of the presence or absence of the residue is called “missing” by those skilled in the art, and indicates the residual amount of the residue with respect to the state where the thick film resist is completely removed. 1 to 5 show the states of film thickness resists developed using the developers of Examples 1 to 3 and Comparative Examples 1 and 2, respectively.

(Metal solubility test)
(Examples 4 to 10)
Tetramethylammonium hydroxide was 2.8% by mass, the types and blending amounts of polyhydric alcohols were as shown in Table 2, and pure water was further added to 100% by mass to prepare a developer.

(Comparative Example 3)
As a control, developer P-7G (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) containing no anticorrosive for metals was used.

  Aluminum was sputtered on a silicon wafer (diameter 6 inches, thickness 0.6 mm) to form an aluminum film having a thickness of 2000 mm. The silicon wafer having the aluminum coating was immersed in the developers described in Examples 4 to 10 and Comparative Example 3 for 6 minutes. By measuring the resistance of the silicon wafer using a resistivity meter (model number VR-70, manufactured by Kokusai Electric Co., Ltd.), the film reduction rate of the aluminum film (the amount of film decrease per minute, unit nm / min) And the film thickness were determined. The results are shown in Table 2.

(Evaluation)
From Table 1, it was found that development can be performed without thick film resist residue by adding 3.5 to 10% by mass of polyhydric alcohol. Moreover, it turns out from Table 2 that the corrosion with respect to a metal can be suppressed by adding a polyhydric alcohol.

FIG. 3 is a diagram illustrating a state after development with a developer according to Example 1. 6 is a diagram illustrating a state after development with a developer according to Example 2. FIG. FIG. 6 is a diagram showing a state after development with a developer according to Example 3. 6 is a diagram illustrating a state after development with a developer according to Comparative Example 1. FIG. 6 is a diagram showing a state after development with a developer according to Comparative Example 2. FIG.

Claims (9)

  A developer for a thick film resist comprising a basic compound (a) and a polyhydric alcohol (b), wherein the polyhydric alcohol (b) is added in an amount of 3% by mass or more to 20% by mass relative to the total amount of the thick film resist developer A developer for a thick film resist, comprising a concentration of less than mass%.   The developer according to claim 1, wherein the basic compound (a) is a quaternary ammonium compound.   The developer according to claim 2, wherein the basic compound (a) is tetramethylammonium hydroxide.   The developer according to any one of claims 1 to 3, wherein the polyhydric alcohol (b) is at least one selected from glycerin, propylene glycol, and ethylene glycol.   The developer according to claim 4, wherein the polyhydric alcohol (b) is glycerin.   Furthermore, the developing solution of any one of Claims 1-5 containing surfactant (c).   The developer according to any one of claims 1 to 6, for developing a thick film resist containing a polyvinyl ether-based additive.   The developer according to claim 7, wherein the polyvinyl ether-based additive is a polyvinyl ether-based plasticizer. Providing a thick film resist;
Selectively exposing the thick film resist through a mask pattern;
Forming the resist pattern by developing the exposed thick film resist with the developer for thick film resist according to any one of claims 1 to 8. Method.