JPH06268356A - Method for using preflux and manufacture of printed wiring board - Google Patents

Abstract

PURPOSE:To form a chemical film which excels in rust preventive, moisture proofness, heat resistance and chemical resistance by applying a preflux containing a specific compound, an organic acid, inorganic acid, a metal compound, ion exchange mater and the like. CONSTITUTION:A compound represented by a formula (However, in the formula; R1 = hydrogen, alkyl group, phenyl alkyl group, allyl group, R2 = alumel group, phenyl alkyl group, R3 = hydrogen, sulfonic acid group, alkyl group, phenyl group, halogen atoms, n=0 to 17) and a water soluble preflux containing an organic acid, a metal compound and the like is applied to a metal surface, and then a rosin preflux or a resin preflux is applied thereto. For the organic acid, an acetic acid and the like are added by 0.01 to 20% with respect to water, and for an effective component, the compound represented by the formula is added by 0.1 to 5% with respect to an acid aqueous solution. Also, for a compound of metal ions, a metal compound such as lithium is added by 0.001 to 5% with respect to water. Thereby, a chemical film which excels in rust preventive can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal anticorrosion treatment, which is used for anticorrosion of a copper or copper alloy circuit portion of a printed wiring board, and has a low melting point cream solder wettability, spreadability, and after reflow. It is suitable as a heat-resistant preflux for improving the solderability of

[0002]

2. Description of the Related Art Preflux, which is used for the purpose of preventing the circuit portion of a printed wiring board made of copper or copper alloy from rusting and maintaining solderability, is a rosin-based or resin-based resin that coats the entire printed wiring board. Pre-flux is used. As an active ingredient, natural rosin, rosin ester, rosin-modified maleic acid resin, etc. dissolved in an organic solvent is applied by a roll coater, or sprayed or dipped to apply to the entire printed wiring board and dried to form a film. Used in the method of forming.

[0003]

In recent years, the surface mounting method has been widely adopted as a method for soldering electronic components to a printed wiring board. Due to this surface mounting method, temporary fixing of electronic parts, low melting point cream solder paste flow, etc., the printed wiring board is often exposed to high temperatures and the heat resistance of the pre-flux used to maintain the solderability of the printed wiring board. That the pre-flux performance is required to have excellent wettability and spreadability of the low melting point cream solder after the printed wiring board is exposed to high temperature, and solder rising property after reflow. became.

[0004]

In view of such circumstances, the present inventors have found that the low melting point cream solder has wettability and spreadability even after being exposed to a high temperature. Solderability after reflow,
As a result of extensive studies on a heat-resistant surface protective agent having good wettability, as the organic acid used in the practice of the present invention, acetic acid, iodoacetic acid, bromoacetic acid, dimethylacetic acid, diethylacetic acid, α-bromoacetic acid, paranitrobenzoic acid were used. Acid, p-toluenesulfonic acid, picric acid, oxalic acid, formic acid, succinic acid, maleic acid, acrylic acid, fumaric acid, tartaric acid,
Organic acids such as adipic acid, lactic acid, oleic acid, citric acid, metasulfonic acid, sulfamic acid, etc., inorganic acids such as hydrochloric acid, sulfuric acid, phosphorous acid, phosphoric acid, other carboxylic acids, halogenated fatty acids, halogenated aromatic carboxylic acids Therefore, it may be added at a ratio of 0.01 to 20% with respect to water. One or two or more compounds represented by (Chemical formula 1) to (Chemical formula 10) may be added as an active ingredient at a ratio of 0.1 to 5% with respect to the acid aqueous solution. Typical examples of the compound as a metal ion used in the method of the present invention include lithium, beryllium, potassium, magnesium, zinc acetate, zinc formate, zinc lactate, zinc counate, zinc benzoate, zinc oxalate, and water. Zinc oxide, zinc bromide, zinc phosphate, zinc oxide, zinc chloride, lead acetate, lead hydroxide, lead bromide, lead iodide, lead oxalate, lead borate, ferrous chloride, ferric chloride, bromide Cuprous, cupric bromide, cuprous iodide, copper formate, nickel chloride, nickel acetate, cuprous chloride, cupric chloride, cuprous oxide, cupric oxide, copper hydroxide, phosphorus It is a metal compound such as copper oxide, copper carbonate, copper acetate, and copper sulfate, and is 0.00 with respect to water.
It may be added at a rate of 1 to 5%. The halogenated aromatic carboxylic acid used in the practice of the present invention is 3
-Bromo-4-methylbenzoic acid, 4- (bromomethyl) phenylacetic acid, α-bromophenylacetic acid, α-bromotetradecanoic acid, 2-bromophenylacetic acid, 3-bromophenylacetic acid, 4-bromophenylacetic acid, etc. In the range of 0.01 to 20%, preferably 0.1 to 5
% May be added. Examples of the halogenated fatty acid used in the practice of the present invention include bromoacetic acid, 3-bromo-2- (bromomethyl) propionic acid, 2-bromobutanoic acid, 4-bromobutanoic acid, 2-bromohexanedecanoic acid, 2-bromohexanoic acid. , 2-bromo-3-methylbutanoic acid, 2-bromo-2-methylpropionic acid, 2-
Bromooctanoic acid, 8-bromooctanoic acid, 2-bromopropionic acid, 3-bromopropionic acid, 2-bromopentanoic acid, 5-bromopentanoic acid, chloroacetic acid, chlorobutyric acid, chloropropionic acid, etc. In the range of 0.01 to 20%, preferably 0.1 to 5%. In the practice of the present invention, when it becomes difficult to dissolve the compounds represented by (Chemical Formula 1) to (Chemical Formula 10) and organic acids, metal compounds, halogenated aromatic carboxylic acids, and halogenated fatty acids, emulsification or methanol Water-soluble solvents such as ethanol, isopropyl alcohol, butanol, and acetone can be used alone, or can be used by mixing them at an arbitrary ratio. For example, the water-soluble solvent may be used in combination with other organic acids or the like, which are used alone.
When it becomes difficult to dissolve the compound represented by (Chemical Formula 1) to (Chemical Formula 10) or its derivative, it is preferable to add a water-soluble solvent, and the content ratio in this case is 0.01 to 6
In many cases, 0% is appropriate. It should be noted that adding a substance having a buffering action such as aqueous ammonia or amines to the treatment liquid is effective not only for enhancing the stability of PH of the aqueous solution but also for accelerating the film formation rate. To apply a rust-preventive conversion coating, a heat-resistant conversion coating, and a chemical-resistant conversion coating to the metal surface with the metal surface treatment agent of the present invention,
Contact the metal with the treatment liquid. As a method of contacting, a method of dipping, spraying or coating is used. It is suitable that the temperature of the treatment liquid to be brought into contact is in the temperature range of 0 to 100 ° C. and the immersion time is several seconds to several tens of minutes. In addition, after forming the chemical conversion film, rosin-based and resin-based pre-flux (for example, RT-02, RT-05, RT-07 manufactured by Tamura Chemical Co., Ltd., R-4000 manufactured by Mech Co., Ltd. ) Asahi Kaken P
-63, KL-741 manufactured by Sanwa Chemical Industry Co., Ltd.,
It was found that applying a pre-flux such as SMT-10 manufactured by Nippon Polytech Co., Ltd. was also effective, and completed the present invention.

[0005]

According to the above-mentioned treatment method, a rust-preventive chemical conversion film mainly composed of (Chemical formula 1) to (Chemical formula 10), a heat-resistant chemical conversion film, and a corrosion-resistant film, which are effective for rust prevention on metal surfaces such as copper and copper alloys, A chemical conversion coating is formed. These chemical conversion coatings are water repellent, rust-proof, moisture-resistant, heat-resistant, have excellent chemical resistance, and protect the metal surface for a long time, as well as wettability and spreadability of low-melting point cream solder,
Good solderability and wettability after reflow. Also, after forming the chemical conversion film, the wettability of the low melting point cream solder by applying a rosin-based or resin-based preflux,
Good spreadability, solderability after reflow, and wettability.

[0006]

EXAMPLES Each containing 1% of the compound represented by (Chemical formula 1) to (Chemical formula 10) (compound described in Table 1), formic acid, carboxylic acid, aqueous ammonia, cupric chloride, ion-exchanged water, etc. A variety of aqueous solutions were prepared, placed in a 100 ml container, and the liquid temperature was adjusted to 40 ° C by heating. On the other hand, 1 cm x 10 cm x 0.3 mm
Prepare a copper sulfate-plated sample piece on the copper plate, and then
, Degreasing, washing with water, soft etching, washing with water, pickling, washing with water, and the surface is washed for 60 seconds in each kind of 1% aqueous solution containing the compound represented by the above (Chemical formula 1) to (Chemical formula 10) as an active ingredient. It was contacted and then washed with water and dried. Tamura RT-07 was applied to the sample pieces of and were dried. R-4000 manufactured by MEC Co., Ltd. was applied to the sample pieces of No. 3, and dried. ,
SPT-10 manufactured by Nippon Polytech Co., Ltd. was applied to the sample piece of No. 1 and dried. , KL manufactured by Sanwa Chemical Industry Co., Ltd.
-714 was applied and dried. Sample pieces of to were prepared, and then cream solder was printed on the sample pieces of (1) to measure the solder spreading rate after the reflow treatment.
Put the sample pieces of (2) to 5 in a hot air dryer at 200 ° C.
It was heated for a minute, immersed in post flux before measurement, and the wetting time was measured using a solder wettability tester. (3) ~
MIL-STD-20 using the moisture resistance tester
2F-M-106E treatment was performed, the test piece was immersed in post flux, and the wetting time was measured using a solder wettability tester. The test results are shown in Table 1.

[Table 1]

[0007]

EFFECTS OF THE INVENTION By applying pre-flux to a metal surface, a chemical conversion coating having excellent rust resistance, moisture resistance, heat resistance and chemical resistance is formed. In addition, after forming the chemical conversion film, by applying rosin-based or resin-based pre-frac, the wettability and spreadability of the low melting point cream solder, and the solder riseability and wettability after reflow are good, so that the electronic component surface It can be particularly effective for implementation.

Claims (7)

[Claims] 1. A water-soluble preflux containing a compound represented by (Chemical Formula 1) to (Chemical Formula 10), an organic acid, a metal compound, etc. is applied to a metal surface, and then a rosin-based preflux or a resin-based preflux is applied. A method of using a pre-flux and a method of manufacturing a printed wiring board. [Chemical 1] [Chemical 2] [Chemical 3] [Chemical 4] [Chemical 5] [Chemical 6] [Chemical 7] [Chemical 8] [Chemical 9] [Chemical 10] 2. A method of using a preflux, which comprises applying a preflux obtained by adding a compound represented by (Chemical Formula 1) to (Chemical Formula 10) to a rosin-based preflux or a resin-based preflux to a metal surface. And a method for manufacturing a printed wiring board. 3. A compound represented by (Chemical Formula 1) to (Chemical Formula 10), an organic acid, a metal compound, and one or more of carboxylic acid, halogenated fatty acid, halogenated aromatic carboxylic acid and the like.
A method for using a preflux and a method for manufacturing a printed wiring board, which comprises applying a water-soluble preflux containing at least one kind to a metal surface and then applying a rosin-based preflux or a resin-based preflux. 4. A surface protective agent for metal and a method for using the same, comprising applying a water-soluble preflux containing a compound represented by (Chemical formula 1) to (Chemical formula 10), an organic acid and a metal compound to a metal surface. . 5. A compound represented by (Chemical formula 1) to (Chemical formula 10), an organic acid, a metal compound, a carboxylic acid, a halogenated fatty acid, a halogenated aromatic carboxylic acid, or the like, or a combination thereof.
A surface protective agent for metal, which comprises applying a water-soluble preflux containing at least one kind to a metal surface, and a method of using the same. 6. A method for manufacturing a printed wiring board, which comprises performing a soldering treatment after the metal surface treatment according to any one of claims 1 to 5. 7. After the metal surface treatment according to any one of claims 1 to 5, infrared reflow, near-infrared reflow, far-infrared reflow, nitrogen reflow, vapor reflow treatment of heating in air or a nitrogen atmosphere is performed. And a method for manufacturing a printed wiring board.