JP2008257113A - Developing solution for solder resist and method for developing printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent generation of sludge due to increase in the concentration of a solder resist, in a developing solution for a solder resist and to prevent re-deposition of sludge onto a substrate made of copper or the like or deposition on a developing tank. <P>SOLUTION: The developing solution for a solder resist contains (A) a diluted alkali aqueous solution, and (B) an ester of polyoxyalkylene fatty acid expressed by formula shown and having an average molecular weight of 1,000 to 10,000, by 0.001 to 2.0 wt.%. In the formula, R1CO represents a 10-22C acyl group; R2 represents a hydrogen atom or a 10-22C acyl group; EO represents an oxyethylene group; PO represents an oxypropylene group; each of X and Y, independently represents an integer of 5 to 200; and the oxyethylene group and the oxypropylene group may be in a form of random polymerization or block polymerization. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, when forming a resist pattern in a manufacturing process of a semiconductor integrated circuit element or the like, or when forming a color filter such as a color liquid crystal display device, light (visible light, ultraviolet ray), X-ray, electron beam, etc. The present invention relates to an alkaline developer used for developing a coating film formed of a photosensitive resin composition that reacts.

  In the manufacture of semiconductor integrated circuit elements and liquid crystal display elements, a photosensitive resin composition called a resist is applied on a substrate to form a resist film, and then the resist film is irradiated in a pattern according to the circuit design. Then, the exposed resist film is developed with an alkaline developer, and unnecessary portions of the resist are dissolved and removed to form a resist pattern.

  A printed wiring board is for mounting a circuit pattern on a circuit board by soldering an electronic component to the soldering land of the pattern, and the circuit part excluding the soldering land is permanent. It is coated with a solder resist film as a protective film. This prevents solder from adhering to unnecessary parts when soldering electronic components to a printed wiring board, and prevents circuit conductors from being directly exposed to air and being corroded by oxidation or humidity. .

  With the demand for higher wiring density (miniaturization) of printed wiring boards, solder resist compositions are also required to have high resolution and high precision. A liquid photo solder resist method (photographic development method) that is excellent in accuracy and coverage of conductor edge portions has been proposed. The solder resist composition is applied on the entire surface of a printed wiring board, a liquid composition, which is a photosensitive resin composition, volatilizes the solvent, exposed to light, and unexposed portions are removed using an organic solvent and developed. Is.

  However, removal (development) of unexposed areas with organic solvents not only has environmental pollution and fire hazards, but also has environmental pollution problems due to the use of large amounts of organic solvents. Has been taken up in recent years, so measures are being taken.

In order to solve these problems, an alkali development type photo solder resist composition that can be developed with a dilute aqueous alkali solution has been proposed. For example, Patent Document 1 discloses a material based on a reaction product obtained by reacting an unsaturated monocarboxylic acid with an epoxy resin and further adding a polybasic acid anhydride. Patent Document 2 discloses an active energy ray-curable resin obtained by reacting a reaction product of a novolac type epoxy resin and an unsaturated monocarboxylic acid with a saturated or unsaturated polybasic acid anhydride, and photopolymerization. A photocurable liquid resist ink composition containing an initiator and developable with a dilute alkaline aqueous solution is disclosed. These liquid solder resist compositions are provided with photosensitivity and developability in a dilute alkaline aqueous solution by introducing a carboxyl group into epoxy acrylate. The composition is further subjected to exposure and development to form a desired resist pattern, and then usually heat-cured.
JP 49-5923 A JP-A 61-243869

Patent Document 3 discloses an alkali developer containing an organic alkali carbonate or hydrogen carbonate substantially free of metal ions and an organic strong alkali.
JP 2001-117240 A

  If development is continued when developing the solder resist coating film, the concentration of the solder resist in the developer increases. During the development process, the solder resist once dissolved in the developer may re-adhere on the copper as sludge. If the re-deposition of the solder resist is on the copper, it may cause the gold plating not to be deposited or the solder not to be deposited. Further, the solder resist also adheres to the inner surface of the developing tank, and reduces the efficiency when cleaning the developing tank.

  An object of the present invention is to prevent sludge generation due to an increase in the concentration of solder resist, re-adhesion of sludge on a substrate such as copper, and adhesion to a developing tank in a solder resist developer.

The present invention provides (A) a dilute alkaline aqueous solution and (B) a polyoxyalkylene fatty acid ester of the following formula having an average molecular weight of 1,000 to 10,000: 0.001 to 2.0% by weight
It is related with the developing solution for solder resist characterized by containing.

（式中、Ｒ１ＣＯは、炭素数１０〜２２のアシル基であり、Ｒ２は、水素または炭素数１０〜２２のアシル基であり、ＥＯはオキシエチレン基を表し、ＰＯはオキシプロピレン基を表し、ＸおよびＹは、それぞれ独立に５〜２００の整数であり、前記オキシエチレン基および前記オキシプロピレン基は、ランダム重合又はブロック重合していても良い。）

(Wherein R1CO is an acyl group having 10 to 22 carbon atoms, R2 is hydrogen or an acyl group having 10 to 22 carbon atoms, EO represents an oxyethylene group, PO represents an oxypropylene group, X and Y are each independently an integer of 5 to 200, and the oxyethylene group and the oxypropylene group may be randomly polymerized or block polymerized.)

  The present invention also relates to a method for developing a printed wiring board, wherein the developer is used to develop a solder resist on the printed wiring board.

  According to the present invention, by adding a polyoxyalkylene fatty acid ester to the solder resist developer, the defoaming action is obtained, and the sludge formation of the solder resist is suppressed, and the sludge reattachment is successfully reduced. .

The solder resist developer of the present invention is based on (A) a dilute alkaline aqueous solution. The dilute alkaline aqueous solution is composed of water and an alkaline substance dissolved in water. Although an alkaline substance is not specifically limited, The following can be illustrated as a particularly preferable thing.
(1) Inorganic alkali: Alkali hydroxide such as potassium hydroxide and sodium hydroxide; Alkali carbonate such as sodium carbonate and potassium carbonate; Alkali phosphate such as sodium phosphate; Alkali silicate such as sodium silicate; Ammonia (2) Organic alkalis such as amines

  The pH of the dilute alkaline aqueous solution is preferably 8.0 to 13.0. From the viewpoint of developability, the pH of the dilute alkaline aqueous solution is more preferably 9.0 or more, and further preferably 11.0 or less.

  In the present invention, (A) contains (B) 0.001 to 2.0% by weight of a polyoxyalkylene fatty acid ester of the following formula having an average molecular weight of 1,000 to 10,000.

  In the above formula, R1CO is an acyl group having 10 to 22 carbon atoms. The acyl group preferably has 15 or more carbon atoms, more preferably 20 or less.

  R2 is hydrogen or an acyl group having 10 to 22 carbon atoms. The acyl group preferably has 15 or more carbon atoms, more preferably 20 or less.

EO represents an oxyethylene group (—CH ₂ —CH ₂ —O—), and PO represents an oxypropylene group (—CH ₂ —CH (CH ₃ ) —O—). The arrangement order of oxyethylene groups and oxypropylene groups in the polymer is not particularly limited. For example, EO and PO may be randomly polymerized. Alternatively, EO and PO may be block polymerized. X and Y are each independently an integer of 5 to 200, more preferably 10 to 100.

  (B) The average molecular weight (definition: weight average molecular weight) of polyoxyalkylene fatty acid ester shall be 1000-10000. When the molecular weight is less than 1000, the defoaming property is deteriorated. If this molecular weight exceeds 10,000, the solubility will deteriorate.

  (B) The quantity of polyoxyalkylene fatty acid ester shall be 0.001-2.0 weight%. By making this 0.001% by weight or more, the effect of the present invention becomes more remarkable. From this viewpoint, the amount of the (B) polyoxyalkylene fatty acid ester is more preferably 0.05% by weight or more. On the other hand, when this amount exceeds 2.0% by weight, it becomes difficult to dissolve in the developer. It becomes. From this viewpoint, the amount of (B) is more preferably 0.5% by weight or less.

  The developer may contain a plurality of (B) polyoxyalkylene fatty acid esters. In this case, the total amount of the plural types of (B) polyoxyalkylene fatty acid esters is 0.001 to 2.0% by weight.

  The developer of the present invention may consist essentially of the components (A) and (B), but inevitable impurities are allowed. Moreover, the other additive component may be contained. As such an additive component, a nonionic surfactant substantially free of metal ions can be exemplified. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene allyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl phenyl ether, polyoxyethylene benzyl phenyl ether, and pluronic-type nonionic interface. Examples include activators, higher sorbitan fatty acid esters, polyoxyethylene alkyl sorbitol fatty acid esters, acetylene glycol / ethylene oxide adducts, and the like. These may be used alone or as a mixture of two or more.

  About the addition amount in the case of adding this nonionic surfactant, it is 0.01-20 weight% normally, Preferably it is 0.1-10 weight%. If this addition amount is less than 0.01% by weight, the effect of adding a nonionic surfactant will not be sufficiently exerted, and if it exceeds 20% by weight, the developer tends to foam and the exposed area As a result, there arises a problem that the dissolution selectivity of the non-exposed portion is lowered.

  Moreover, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, etc. can be added to the developing solution of this invention.

  Examples of the anionic surfactant include alkyl sulfates, higher alcohol sulfates, alkylbenzene sulfonates, alkyl naphthalene sulfonates, phosphate esters, sulfosuccinate esters, alkyl diphenyl ether sulfonate ammonium salts, and the like. It is done. In addition, examples of the cationic surfactant include quaternary ammonium salts such as lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, and triamylmethylammonium chloride. Examples of zwitterionic surfactants include imidazoline derivatives and betaine type compounds.

  The solder resist on the printed wiring board can be developed using the developer of the present invention. This embodiment will be further described.

  For example, a solder resist is applied in a desired thickness, for example, 5 to 100 μm, on a printed wiring board having a circuit pattern formed by etching a copper foil of a copper-clad laminate. As a coating means, full-scale printing by the screen printing method is generally used at present, but any means may be used as long as it can be applied uniformly including this. For example, spray coaters, phone melt coaters, bar coaters, applicators, blade coaters, knife coaters, air knife coaters, curtain flow coaters, roll coaters, gravure coaters, offset printing, dip coaters, brush coating, and other ordinary methods can be used.

  After coating, pre-baking is performed in a hot air furnace or a far-infrared furnace as necessary, that is, temporary drying is performed to bring the surface of the coating film into a tack-free state. The prebaking temperature is preferably about 50 to 100 ° C.

Next, LDI (Laser Direct
exposure by laser direct drawing using imaging). Alternatively, exposure with active energy rays is performed using a negative mask that prevents the passage of active energy rays. As the negative mask, a negative film is used when the active energy ray is ultraviolet, a metal mask is used when it is an electron beam, and a lead mask is used when it is an X-ray, but it can be printed because a simple negative film can be used. In the production of wiring boards, ultraviolet rays are often used as active energy rays. The irradiation amount of ultraviolet rays may be about 10 to 1000 mJ / cm ² .

  In the case of manufacturing a printed wiring board, for example, a negative film having a light-transmitting pattern other than a soldering land having a circuit pattern is brought into close contact, and ultraviolet rays are irradiated thereon. The coating film is developed by removing the non-exposed areas corresponding to the soldering lands with the dilute alkaline aqueous solution of the present invention.

  Next, when the solder resist contains a thermosetting compound, the post cure is performed by, for example, heating for 20 to 80 minutes with a dryer such as a hot air furnace or a far infrared furnace at 130 to 170 ° C. This makes it possible to form a solder resist film.

  In this way, a printed wiring board coated with a solder resist film is obtained, on which electronic components are connected, fixed and mounted by soldering by a jet soldering method or a reflow soldering method. A circuit unit is formed.

  In the present invention, the printed wiring board coated with the solder resist film before mounting the electronic component and the printed wiring board mounted with the electronic component mounted on the printed wiring board are included in the object.

Example 1
(A) 0.01% by weight of (B) polyoxyalkylene fatty acid ester (“KEI Deformer TK-1000” manufactured by Nippon Steel Environmental Engineering Co., Ltd.) is added to a 1% by weight sodium carbonate aqueous solution to obtain a developer. It was. In this product, R 1 CO is an acyl group having 17 carbon atoms, R 2 is an acyl group having 17 carbon atoms, X is 10-50, and Y is 30-80. (B) The molecular weight of the polyoxyalkylene fatty acid ester is 2000 to 4000.

(Example 2)
(A) 0.1% by weight of (B) polyoxyalkylene fatty acid ester (“KE Deformer TK-1000” manufactured by Nippon Steel Environmental Engineering Co., Ltd.) is added to a 1% by weight aqueous sodium carbonate solution to obtain a developer. It was.

(Example 3)
(A) 1.0% by weight of (B) polyoxyalkylene fatty acid ester (“KEI Deformer TK-1000” manufactured by Nippon Steel Environmental Engineering Co., Ltd.) is added to a 1% by weight sodium carbonate aqueous solution to obtain a developer. It was.

Example 4
(A) 0.1% by weight of (B) polyoxyalkylene fatty acid ester (manufactured by Nippon Steel Environmental Engineering Co., Ltd. “KE Deformer TK-1000”) is added to a 1% by weight aqueous potassium carbonate solution to obtain a developer. It was.

(Example 5)
(A) 0.1% by weight of (B) polyoxyalkylene fatty acid ester (“Silicaton SN-500” manufactured by Taki Chemical Co., Ltd.) was added to a 1% by weight sodium carbonate aqueous solution to obtain a developer. In the formula, R1CO is an acyl group having 17 carbon atoms, R2 is an acyl group having 17 carbon atoms, X is 10 to 50, and Y is 30 to 80. (B) Molecular weight of polyoxyalkylene fatty acid ester Is 1000 to 3000.

(Comparative Example 1)
(A) 0.1% by weight of (B) modified silicone (eg, “Antix # 100” manufactured by Maruzen Pharmaceutical Co., Ltd.) was added to a 1% by weight sodium carbonate aqueous solution to obtain a developer.

(Comparative Example 2)
(A) 0.1 wt% of (B) modified silicone (“Antix # 100” manufactured by Maruzen Pharmaceutical Co., Ltd.) was added to a 1 wt% potassium carbonate aqueous solution to obtain a developer.

  As the solder resist, “DSR-2200P48” (two-component type) manufactured by Tamura Kaken Co., Ltd. was used. After mixing a curing agent with the main agent, a bar coater was applied on a Teflon (registered trademark) plate at a thickness of 70 μm. A solder resist sample was obtained by evaporating the solvent in a hot-air circulating drying oven at 80 ° C. for 20 minutes and preliminarily drying it, and then removing it with a spatula. In the developers of Examples 1 to 5 and Comparative Examples 1 and 2, 1% by weight of the solder resist sample which had been pre-dried was dissolved.

(Evaluation methods)
(Defoaming property):
30 cc of each developer of Examples 1 to 5 and Comparative Examples 1 and 2 in which the solder resist sample is dissolved is placed in a 50 cc glass bottle, shaken for 30 seconds, and then the time until the bubbles disappear is measured.
(Dispersibility):
The evaluation liquid is allowed to stand in a thermostatic bath (30 ° C.-48 hours) to settle the sludge, and then the dispersibility of the sludge in the supernatant is visually observed.
(specific gravity):
The sludge after standing at 30 ° C. for 48 hours was collected by carefully removing the supernatant, and the weight was measured with a specific gravity cup meter to determine the specific gravity.
(Parallel plate viscosity):
The spread diameter (mm) after 30 seconds of the above sludge (0.4 ml) was measured with a parallel plate viscometer (Model VR-5510, manufactured by Ueshima Seisakusho) based on JIS K5101.

As can be seen from the results in Table 1, in the present invention, a practically sufficient defoaming action was obtained. And the dispersibility of a soldering resist sample was favorable, and aggregation was not seen. When sludge is collected from the developer in which the solder resist sample is dispersed, the specific gravity of the collected sludge is remarkably low and the viscosity is low. This indicates that the sludge is light and less likely to reattach.

Claims (3)

(A) a dilute alkaline aqueous solution, and (B) 0.001 to 2.0% by weight of a polyoxyalkylene fatty acid ester of the following formula having an average molecular weight of 1,000 to 10,000
A developer for a solder resist characterized by containing.

(In the formula, R1CO is an acyl group having 10 to 22 carbon atoms, R2 is hydrogen or an acyl group having 10 to 22 carbon atoms, EO represents an oxyethylene group, PO represents an oxypropylene group, X and Y are each independently an integer of 5 to 200, and the oxyethylene group and the oxypropylene group may be randomly polymerized or block polymerized.)   The developer for a solder resist according to claim 1, wherein the pH of the dilute alkaline aqueous solution is 8.0 to 13.0.   A developing method for a printed wiring board, comprising: developing a solder resist on the printed wiring board using the developer according to claim 1.