JPH1117316A - Manufacture of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method, wherein discoloration failure on a conductor pattern after rust-proof treatment can be reduced, cost reduction is realized by improving the yield and productivity of a manufacturing process, and a load larger than the present state is not applied to the environment, in a printed wiring board used in a various kinds of electronic apparatuses. SOLUTION: In a rinsing booth 1c, the surface of the land part of a conductor pattern which is exposed from a solder resist on the surface of a printed wiring board is wetted by water jetted from a water nozzle 1e. At the same time, the surface is physically rubbed by a roller 1f performing rubbing treatment, and air bubbles which cause treatment irregularity are eliminated. In an acid treatment booth 1g, the surface of the land part is covered with an acid treatment liquid, in such a manner that previously attached water is substituted. Rust, oil components, foreign matters, etc., which have attached on the surface of the land part are eliminated and cleaned by a roller 1j for performing rubbing treatment. Thereby discoloration due to treatment irregularity at the time of acid treatment can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board widely used in electronic equipment such as mobile communication equipment and portable information terminals.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become lighter, thinner and smaller, multifunctional, and electronic components mounted on printed wiring boards have been surface mounted, the size and density of component mounting lands have also been increased in printed wiring boards. It is required and has been used in practice.

Conventionally, a device as shown in FIG. 3 is generally used as a rust prevention treatment device for these printed wiring boards.

In FIG. 3, 3a is a loading booth, 3b is an acid treatment booth, 3c is a rust prevention booth, 3d is a conveyor, 3e is a chemical solution supply device, 3f is a take-out booth,
g and 3h are chemical liquid injection nozzles.

[0005] A method for rust-proofing a printed wiring board will be described below with reference to FIG. The printed wiring board processed into the required external shape is fed from the loading booth 3a to the conveyor 3
d and carried into the rust prevention treatment device. The loaded printed wiring board is exposed at the acid treatment booth 3b by injecting an acid treatment liquid generally composed of hydrochloric acid, sulfuric acid, sulfuric acid, and hydrogen peroxide from a chemical solution spray nozzle 3g to thereby expose the land exposed from the solder resist. The part is cleaned, and rust, oil, foreign matter, etc. attached to the surface are removed and cleaned.

[0006] Next, the rust-preventing agent is carried into the rust-prevention treatment booth 3c by the transport conveyor 3d, and is cleaned by the acid treatment booth 3b by the rust-prevention treatment agent sprayed from the chemical spray nozzle 3h onto the surface of the land. Is carried out from the take-out booth 3f, and the rust prevention treatment is completed.

Here, for the sake of explanation, the method of chemical treatment is a spray method from a chemical injection nozzle, but the same rust preventive treatment is also possible by providing a chemical tank and performing a rust preventive treatment by a dipping method. .

[0008]

However, in the above-mentioned conventional method, since unprocessed portions in which processing unevenness has occurred during the acid treatment are generated, discoloration failure occurs on the lands exposed from the solder resist after the rust prevention treatment. As a countermeasure, the yield and productivity of the manufacturing process of the printed wiring board have been remarkably deteriorated, and as a countermeasure, a method of adding a surfactant to the acid treatment liquid to improve the wettability of the acid treatment, or an acid treatment liquid Measures such as increasing the acid concentration in the medium and improving the processing capacity, and increasing the processing time by slowing down the conveyor speed or increasing the booth length have been widely implemented. Secondary defects such as reduced productivity and reduced conductor pattern size due to over-processing,
Increasing costs and complicating the management of the processing solution, the problem that the surfactant in the processing waste solution may have an adverse effect on the environment, and the chip size package (referred to as CSP) for recent high-density mounting. However, this method cannot cope with the acid treatment of the small land portion, and has a problem that a discoloration defect remains.

The present invention has been made to solve the above-mentioned conventional problems. By performing a treatment for improving the cleaning property in the acid treatment in the rust prevention treatment step and then performing the acid treatment, acid treatment unevenness occurs. Rust prevention treatment is possible without reducing the cost.Improving the yield and productivity of the printed wiring board manufacturing process to reduce costs. It is an object of the present invention to provide a method of manufacturing a printed wiring board which does not increase compared to the current situation.

[0010]

In order to solve this problem, a method of manufacturing a printed wiring board according to the present invention comprises providing a conductor pattern on the surface of an insulator, and covering the conductor pattern with a solder resist except for a land. In printed wiring boards,
This is a method in which the surface of the land portion is subjected to a treatment for improving the cleaning property of the acid treatment liquid, and then subjected to an acid treatment, and then to a rust preventive treatment for the land portion, thereby preventing treatment unevenness in the acid treatment. Can reduce discoloration defects on the lands after rust prevention treatment, reduce costs by improving the yield and productivity of the manufacturing process, and do not increase the burden on the environment from the current level. become.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a printed wiring board in which a conductor pattern is provided on the surface of an insulator, and the conductor pattern is covered with a solder resist except for a land. This is a method of performing rust-prevention treatment on the lands after performing a treatment to improve the cleaning properties of the surface of the lands. This method can reduce the processing unevenness during the acid treatment and reduce the land exposed from the solder resist during the rust-prevention treatment. This has the effect of reducing discoloration defects in the part.

According to a second aspect of the present invention, in the first aspect, a water rinsing treatment is performed in advance of the acid treatment step as a treatment for removing bubbles that cause processing unevenness.
By replacing the acid treatment liquid with water adhering to the lands exposed from the solder resist at the time of the acid treatment, it is possible to remove bubbles that cause unevenness in the treatment.

According to a third aspect of the present invention, the substrate surface is physically rubbed at the time of performing the water washing process in the second aspect, and even a minute land portion exposed from the solder resist is used. By having water adhered to the surface of the land part by forcibly attaching the water to the land part at the time of the acid treatment, the acid treatment liquid is replaced with the acid treatment liquid, thereby having an effect of removing bubbles which cause unevenness in the treatment. .

According to a fourth aspect of the present invention, in the second aspect, the ultrasonic treatment is performed in the treatment tank when performing the water washing process, and the land portion exposed from the solder resist at the time of the water washing is provided. By removing the air bubbles adhered to the surface by ultrasonic waves and securely adhering water to the lands, the acid treatment liquid is replaced with the water adhering to the lands during the acid treatment to reduce acid treatment unevenness. It has the effect of being able to.

According to a fifth aspect of the present invention, there is provided a printed wiring board having a conductor pattern on the surface of an insulator and covering the conductor pattern with a solder resist except for a land. The rust preventive treatment is performed in this rust preventive treatment liquid while improving the cleaning property of the treatment liquid. This method can reduce the unevenness of the treatment during the acid treatment and the portion exposed from the solder resist during the rust prevention treatment. Has an effect of reducing discoloration failure of the land portion.

According to a sixth aspect of the present invention, when performing the acid treatment in the fifth aspect, the surface of the substrate is physically rubbed, and even if the land is a minute land exposed from the solder resist. It is possible to forcibly perform the acid treatment on the surface of the land portion, which has the effect of reducing acid treatment unevenness.

According to a seventh aspect of the present invention, when performing the acid treatment in the fifth aspect, the ultrasonic treatment is performed in the treatment tank, and the treatment adhered to the land portion exposed from the solder resist during the acid treatment. It has the effect that bubbles that cause unevenness can be removed by ultrasonic waves and unevenness in acid treatment can be reduced.

An embodiment of the present invention will be described below with reference to FIGS. (Embodiment 1) FIG. 1 is a schematic configuration diagram showing the configuration and operation of a rust prevention treatment apparatus according to an embodiment of the present invention.

In FIG. 1, a printed wiring board carried in from a loading booth 1a is carried into a washing booth 1c by a conveyor 1b. In the washing booth 1c, the printed wiring board is supplied from the water supply device 1d, and the surface is wetted by the water jetted from the water jet nozzle 1e, and at the same time, the surface of the printed wiring board is physically rubbed by the roller 1f for rubbing. Rubbed.

Next, the printed wiring board, which has entered the acid treatment booth 1g by the transport conveyor 1b,
The rust, oil, foreign matter, and the like attached to the surface of the land portion are removed and cleaned by the acid treatment liquid supplied from h and injected by the acid treatment liquid injection nozzle 1i and the roller 1j for rubbing.

Next, the printed wiring board that has entered the rust-prevention treatment booth 1k by the conveyor 1b is supplied from the rust-prevention treatment liquid supply device 11 and is landed by the rust-prevention treatment liquid sprayed from the rust-prevention treatment liquid injection nozzle 1m. The surface of the part is rustproofed. Then, it is dried in the drying booth 1n, taken out from the takeout booth 1p, and the rust prevention treatment is completed.

Next, the action of preventing discoloration due to acid treatment unevenness by the above method will be described.

In FIG. 1, the printed wiring board is formed by water and a roller 1f jetted from a water jet nozzle 1e.
The surface of the land portion is forcibly wetted, and air bubbles that cause processing unevenness on the surface of the land portion are removed, and are then carried into the acid treatment booth.

In the acid treatment booth 1g, the acid treatment liquid covers the surface of the land portion and rubs the printed wiring board in such a manner that the acid treatment liquid sprayed from the acid treatment liquid spray nozzle 1i is replaced with water previously attached. By removing and cleaning the rust, oil, foreign matter and the like attached to the surface of the land by the roller 1j for performing the treatment, it is possible to prevent discoloration due to unevenness in the treatment during the acid treatment.

(Embodiment 2) FIG. 2 is a schematic configuration diagram showing the configuration and operation of a rust prevention treatment apparatus according to another embodiment of the present invention.

In FIG. 2, a printed wiring board carried in from a loading booth 2a is carried into a washing booth 2c by a conveyor 2b. In the water washing booth 2c, the surface of the printed wiring board is wetted by immersion (dip) treatment with water supplied from the water supply device 2d and given vibration by the ultrasonic generator 2e.

Next, the printed wiring board that has entered the acid treatment booth 2f by the transport conveyor 2b is
The rust, oil, foreign matter, etc. adhered to the surface of the land portion are removed by an immersion (dip) treatment with an acid treatment liquid supplied from the g and vibrated by the ultrasonic generator 2h to be cleaned.

Next, the printed wiring board that has entered the rust-prevention treatment booth 2i by the conveyor 2b is supplied with rust-prevention treatment liquid supplied from the rust-prevention treatment liquid supply device 2j, and is ejected from the rust-prevention treatment liquid spray nozzle 2k. The surface of the part is rustproofed. Then, it is dried in a drying booth at 2 liters, taken out from the take-out booth 2m, and the rust prevention treatment is completed.

Next, the action of preventing discoloration due to acid treatment unevenness by the above method will be described.

In FIG. 2, the printed wiring board is forcibly adhered to the surface of the land portion in advance by the water vibrated by the ultrasonic generator 2e in the washing booth 2c, and the treatment on the surface of the land portion is performed. Bubbles that cause unevenness are removed and carried into an acid treatment booth.

In the acid treatment booth, the printed wiring board is immersed (dipped) in an acid treatment solution vibrated by the ultrasonic generator 2h so that the acid treatment solution replaces the water previously attached to the acid treatment solution. By covering the surface of the land portion and removing and cleaning rust, oil, foreign matter, etc. attached to the surface of the land portion, discoloration due to unevenness in the acid treatment can be prevented.

[0032] For the sake of explanation, the spray method was used as a treatment method in the rust preventive treatment booth, but the rust preventive treatment using a dipping (dip) method is also widely used. Needless to say.

Table 1 shows the results of experiments comparing the effects of the embodiment of the present invention with the conventional method.

[0034]

[Table 1]

[0035]

As is apparent from the above description, according to the present invention, it is possible to prevent the adhesion of bubbles which may cause unevenness in the acid treatment as a pre-treatment for the rust prevention treatment. Unevenness does not occur, discoloration failure during rust prevention treatment is reduced, and the yield can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing the configuration and operation of a rust prevention treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing the configuration and operation of a rust prevention treatment apparatus according to another embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing the configuration and operation of a conventional rustproofing device for printed wiring boards.

[Description of Signs] 1a Input Booth 1b Conveyor 1c Rinse Booth 1d Water Supply Device 1e Water Injection Nozzle 1f Roller for Scrubbing 1g Acid Treatment Booth 1h Acid Treatment Liquid Supply Device 1i Acid Treatment Liquid Injection Nozzle 1j Roller for Scrubbing 1k Rust prevention treatment booth 1l Rust prevention treatment liquid supply device 1m Rust prevention treatment liquid injection nozzle 1n Drying booth 1p Removal booth 2a Input booth 2b Conveyor 2c Rinse booth 2d Water supply device 2e Ultrasonic generator 2f Acid treatment booth 2g Acid treatment Liquid supply unit 2h Ultrasonic wave generator 2i Rust prevention treatment booth 2j Rust prevention treatment liquid supply unit 2k Rust prevention treatment liquid spray nozzle 2l Drying booth 2m Removal booth

Claims (7)

[Claims] 1. A printed wiring board in which a conductor pattern is provided on a surface of an insulator, and the conductor pattern is covered with a solder resist while leaving a land, and then subjected to a treatment for improving the cleanability of the surface of the land, followed by acid cleaning. And then a rust prevention treatment of the land portion. 2. The method for manufacturing a printed wiring board according to claim 1, wherein a water washing process is performed in advance as a process for improving the cleanability of the surface of the land portion. 3. The method of manufacturing a printed wiring board according to claim 2, wherein the lands are rubbed during the water-washing treatment to improve the cleanability of the surface of the lands. 4. The method for producing a printed wiring board according to claim 2, wherein ultrasonic treatment is performed when the water washing process is performed to improve the cleanability of the surface of the land portion. 5. A printed wiring board having a conductor pattern provided on the surface of an insulator and covering the conductor pattern with a solder resist while leaving a land, a rust prevention treatment solution is supplied to the surface of the land, and the rust prevention treatment is performed. A method for manufacturing a printed wiring board in which rust prevention treatment is performed while improving the cleaning property of the treatment liquid in the liquid. 6. The method for producing a printed wiring board according to claim 5, wherein the treatment is performed by rubbing the land portion in the rust-preventive treatment liquid to improve the cleaning property of the treatment liquid. 7. The method for producing a printed wiring board according to claim 5, wherein the treatment is performed by using ultrasonic waves in the rust preventive treatment liquid to improve the cleaning property of the treatment liquid.