JP3250265B2 - Manufacturing method of printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a printed wiring board used for mounting electric and electronic parts.

[0002]

2. Description of the Related Art In recent years, a conductive method by through-hole plating of small-diameter via holes between layers of a multilayer laminate has been adopted in response to higher density wiring of the multilayer laminate. However, when the diameter becomes small, the method of suspending the printed wiring board for processing, which is usually employed in the processing step of the printed wiring board, perpendicularly to the surface of the processing solution, and processing the printed wiring board with a conditioning liquid, an electroless In a solution tank of various solutions such as a plating solution, an electroplating solution, and a rinsing solution, air bubbles and a processing solution in a previous step remain in the small-diameter hole, and the processing with the original processing solution cannot be sufficiently performed. For example, in the case of through-hole plating, plating defects appear, and there is a problem that through-hole plating quality and through-hole reliability cannot be ensured.

As a countermeasure, a method of vertically suspending a processing printed wiring board and treating the suspension frame jig with a cylinder every 10 to 60 seconds or removing 4 to 10 Oscillating in a second cycle facilitates the penetration of the processing solution into the small diameter hole. For this purpose, it is necessary to separately install these impact and swinging devices.

[0004] Further, there have been attempts to reduce the viscosity and surface tension of the processing solution so that the processing solution can easily come out of a small-diameter hole.

Japanese Patent Application Laid-Open No. 4-154192 discloses a printed wiring board 2 having a through hole 7 as shown in the sectional view of FIG.
Of the plating solution at an angle A of 45 degrees or less with respect to one surface of the plating solution, and a technique of impacting and vibrating the installation jig 4 of the printed wiring board 2 by means 6 for impacting at a specific acceleration. Are disclosed. According to the prior art, as a conventional technique, a printed wiring board 2 having a through hole 7 as shown in a sectional view of FIG. 5 is also disclosed. However, there is no suggestion regarding a technique for completely injecting the processing solution into the small-diameter hole and the via hole in the first tank, and then completely replacing the processing solution in the second and subsequent layers of the same processing solution.

[0006]

Therefore, using a conventional apparatus for suspending a printed wiring board perpendicularly to the surface of a processing solution and using the conventional processing solution to perform uniform solution processing on small-diameter holes. It is to provide a possible manufacturing method.

[0007]

The feature of the present invention made in view of the above points is that, in the process of processing a printed wiring board, when this board is processed by a plurality of solution tanks for various solutions, In at least the first tank of these solution tanks, the plate is processed horizontally with respect to the processing solution surface,
Then, in the same type of solution tank, the plate is placed against the processing solution surface.
A method for manufacturing a printed wiring board, wherein the printed wiring board is processed in a vertical state.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of an electroplating process having four solution tanks from a first to a fourth tank. In a first electroplating solution tank 8, a processing printed wiring board 2 having a via hole of a small diameter hole 3 is suspended on an installation jig 4 in a horizontal state with respect to the plating solution 1 surface, and air bubbles in the small diameter hole 3 are formed. 5 is removed, or a predetermined plating solution 1 is made to enter the small-diameter hole 3. Further, initial generation of plating is performed. At this time, it is preferable to give an impact or swing to the installation jig 4.

After the electroplating solution tank 9 of the second tank, in the electroplating solution tank 11 of the fourth tank, the plating solution that has entered the small-diameter hole 3 is sequentially replaced by osmotic pressure due to the concentration difference, and the predetermined plating is performed at 100%. become. As a result, the treatment with the predetermined plating solution of 100% is continuously performed, so that the through-hole plating with no defect in the small-diameter hole 3 can be performed.

As the electroplating solution, a commonly used one can be used as it is. In addition, as a processing solution other than the electroplating solution, a technology related to processing in various solution tanks such as a conditioning solution, an electroless plating solution, and a rinsing solution used in processing of a printed wiring board can be applied. In the first tank of the processing solution, a low-concentration state of the predetermined solution is formed in the small-diameter hole.
It is possible to process with a predetermined solution of 00%.

Although the present invention is particularly effective for small-diameter holes and via holes, it can also be applied to ordinary through-hole through holes.

[0013]

[Function] A printed wiring board for processing is applied to the surface of the processing solution.
In order to treat in the horizontal state in the first tank , bubbles in the small-diameter hole naturally escape by gravity. In the small-diameter hole, the solution of the previous step and the predetermined solution are mixed and accumulated in the first tank of the predetermined solution, and the concentration of the predetermined solution is lower than the concentration of the predetermined solution in the second and subsequent tanks. In the second and subsequent tanks, the osmotic pressure due to the concentration difference causes spontaneous replacement to the predetermined processing solution concentration continuously, and the predetermined processing solution 1
00% processing is possible.

As a result, uniform through-hole plating can be performed in the plating step, and the reliability of through-hole conduction can be ensured.

[0015]

According to the present invention, it is possible to perform uniform solution processing on small-diameter holes using a conventional processing solution by using a conventional apparatus for suspending a printed wiring board perpendicularly to a processing solution surface. As an example, uniform through-hole plating can be performed on a small-diameter hole, and through-hole conduction reliability can be ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional example.

FIG. 3 is a sectional view showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plating solution 2 Printed wiring board 3 Small diameter hole 4 Installation jig 5 Air bubble 6 Impact means 7 Through hole 8 Electroplating solution tank of 1st tank 9 Electroplating solution tank of 2nd tank 10 Electroplating solution tank of 3rd tank 11 4th electroplating solution tank

Claims (1)

(57) [Claims] 1. A processing step of the printed wiring board, when processing each of a plurality of solution tanks for the plate various solutions, first of all at least the processing solution surface the plate in the first vessel th these solution vessel to And process it horizontally.
A method for manufacturing a printed wiring board, characterized in that said board is processed in the same type of solution tank in a state perpendicular to the surface of the processing solution .