JP2001111183A - Printed wiring board for reliability evaluation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board for reliability evaluation which enables the accurate reliability evaluation of punching workability as well as the reliability evaluation of a wiring part. SOLUTION: A printed wiring board 10 comprises a board 11 and a wiring part 20 consisting of conductive patterns 21, 22 and 23. The board has a plurality of evaluation pattern regions 12, 13 and 14. At least, one region 12 among the evaluation pattern regions has the pattern 21 suitable for the reliability evaluation of punching workability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board for evaluating reliability provided with an evaluation pattern for evaluating the reliability of punching.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for smaller and lighter electronic devices in accordance with changes in use such as personalization and portability, and high-density mounting and modularization of components have been rapidly progressing. It is going to. Then, in connection with the high-density mounting, it is necessary to reduce the wiring length by narrowing the distance between pads and the high-density wiring pattern in order to enable bare chip mounting even on a printed wiring board. For this reason, the evaluation of the reliability of the wiring portion of the printed wiring board has become important, and the reliability of the punching property has also been required.

Conventionally, the reliability of the wiring portion and the punching property of such a printed wiring board has been evaluated by separately preparing an evaluation sample having one type of evaluation pattern and using these evaluation samples. It has been done.

[0004]

For this reason, since a separate evaluation sample is required, the cost is increased, and the evaluation work is complicated and troublesome. Also, when performing the reliability evaluation of the punching performance, without considering the effects of various stresses on the printed wiring board in the manufacturing process, for example, thermal stress in the punching process, etc.
We are evaluating reliability. For this reason, there was a problem that it was not possible to accurately and practically evaluate the reliability of punching.

SUMMARY OF THE INVENTION In view of the above, the present invention provides a print for reliability evaluation in which the reliability of the punching of a printed wiring board is evaluated accurately and the reliability of the wiring portion is also evaluated. It is intended to provide a wiring board.

[0006]

According to the first aspect of the present invention, there is provided a printed wiring board having a substrate and a wiring portion formed by a conductive pattern formed on the substrate. A plurality of different types of evaluation pattern areas, and at least one of the above areas has a pattern suitable for punching reliability evaluation. This is achieved by the substrate.

According to the first aspect of the present invention, since an evaluation pattern for evaluating the reliability of punching in at least one region is punched by being manufactured in the same manner as a normal printed wiring board, A dimensional error occurs due to a stress in the manufacturing process, for example, an elastic contraction or a heat contraction of a punched hole due to a thermal stress or the like at the time of punching. Therefore, the reliability of the punching performance, such as the hole diameter, the hole position, and the outer shape punching accuracy, which takes into account the effects of stress in the manufacturing process, is evaluated. is there.

According to the second aspect of the present invention, when the area of the plurality of evaluation patterns includes a pattern for evaluating the reliability of the wiring portion of the printed wiring board, the reliability evaluation of the wiring portion is performed. The evaluation pattern for
For example, the reliability of the wiring portion such as insulation, withstand voltage, solder resist characteristics, and conductor adhesion is evaluated. Therefore, the reliability evaluation of the punching property and the reliability evaluation of the wiring portion can be reliably performed by one printed wiring board.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. still,
Since the embodiments described below are preferred specific examples of the present invention, various technically preferred limitations are added.
The scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

FIGS. 1 to 3 show an embodiment of a printed wiring board to which the present invention is applied. In FIG.
The printed wiring board 10 is a single-sided printed wiring board, and has a substrate 11 and a wiring portion 20 formed of a conductive pattern formed on the surface of the substrate 11.

The substrate 11 is, for example, a substrate having a length of 245 mm × width 328 mm × thickness 1.6 mm, and a wiring section 20 provided on the surface thereof has first to third Each of the regions 12, 13, 14 is formed with a conductive pattern having a corresponding shape. Each area 12, 13, 1
At 4, the surface other than the conductive pattern is coated with the solder resist 15 of FIG. 2 by printing or the like, and is cured.

Here, in the first area 12, an evaluation pattern 21 for evaluating the reliability of punching is formed. This evaluation pattern 21 is divided into divided areas 21
a, 21b, which is a conductive pattern of any shape formed on the surface of the region 12, having the same structure,
The outer shape 1 and the component mounting hole 16 are formed by punching. This punching process is performed by a punching die, for example, by raising the temperature to an optimal punching temperature (for example, about 100 ° C. for the surface layer) for the substrate 11 by an auto press heater. In the areas 13 and 14 to be described later, it is necessary to delete evaluation pins.

In the second region 13, an evaluation pattern 22 for evaluating the reliability of the wiring portion is formed.
As shown in an enlarged manner in FIG. 3, the evaluation pattern 22 has five pads 22a, 22b, and 2 of a predetermined size.
2c, 22d, and 22e, the elongated patterns 22 alternately arranged in a comb shape from the a side and the b side.
f, 22g. In this case, the patterns 22c and 22d of each set have a pitch of, for example, 75 μm.

In the third region 14 of FIG. 1, an evaluation pattern 23 for evaluating the reliability of the copper foil peelability is formed. As shown in FIG. 1, the evaluation pattern 23 is composed of two parallel patterns 23a and 23b.

The printed wiring board 10 is manufactured, for example, as shown in FIG. First, FIG.
In (A), a so-called single-sided printed wiring board 30 having a copper foil 31 adhered over the entire surface thereof is used. 4B, the single-sided printed wiring board 3
In the pattern printing step, the openings 3 having the same pattern as the conductive patterns 21, 22, and 23 are formed on the surface of the copper foil 31.
A resist mask 32 having 2a is formed. Subsequently, in an etching step, the copper foil 31 exposed in the opening 32a of the resist mask 32 is removed.
As shown in (C), the resist mask 32 is peeled off.

Thereafter, as shown in FIG. 4D, the solder resist 15 is printed and hardened on portions other than the remaining copper foil 31 (conductive patterns 21, 22, 23). Finally, as shown in FIG. 4E, punching is performed on the outer periphery of the substrate 30 and a predetermined portion of the conductive pattern 21 by punching, so that the component holes 16 are formed and the individual substrates are removed from the substrate 30. 11 is cut out.

The printed wiring board 10 according to the present embodiment
Is configured as described above, and the reliability evaluation is performed as follows. That is, as an evaluation test of the punching property, the component hole 1 based on the evaluation pattern 21 shown in FIG.
The hole diameter and hole position after punching and the precision of punching the outer shape of the substrate 11 are visually observed or observed with a magnifying glass. In this case, since the printed wiring board 10 is punched in the same manner as a normal printed wiring board as described above, the hole diameter of the component hole 16 after completion depends on elastic shrinkage and thermal stress at the time of punching. Due to the heat shrinkage, the diameter is reduced to about 80 to 90% of the diameter of the punch used for the punching process. At this time, the amount of shrinkage varies depending on the punch diameter, the thickness and material of the substrate 11, the clearance between the punch diameter and the die hole diameter, and the heating temperature, but the manufacturing is performed by evaluating the hole diameter of the component hole 16 after completion. A more accurate and practically reliable reliability evaluation of the punching performance taking into account the stress in the process is performed.

Next, as a test for evaluating the adhesiveness of the solder resist, a new adhesive surface of the transparent adhesive tape was pressed on the above-mentioned evaluation pattern 21 by finger pressure or another method so that no air bubbles remained, and after 10 seconds, Thereafter, the transparent adhesive tape is quickly peeled off in a direction perpendicular to the pattern 21. Then, the floating of the solder resist 15 around the evaluation pattern 21 on the substrate 11 and the adhesion of the solder resist to the adhesive surface of the transparent adhesive tape are visually or visually observed with a magnifying glass.

Further, as an evaluation test of the insulation properties of the wiring portion,
For example, pads 22a and 22b of the evaluation pattern 22
In between, while applying a DC voltage of 50 or 100V,
It is left in a thermo-hygrostat kept at 40 ° C. ± 2 ° C. and 90-95% RH (related humidity) for 1000 hours, and the insulation resistance value is measured. In order to shorten the test time, an accelerated test, that is, while applying a DC voltage of 50 or 100 V, was carried out in a thermo-hygrostat kept at 85 ° C. ± 2 ° C. and 85 ± 2% RH (related humidity). You may leave it for 240 hours and measure an insulation resistance value. In this case, an evaluation test of the insulating property of the solder resist 15 is also performed at the same time.

Further, as an evaluation test of the withstand voltage of the wiring portion, for example, the pads 22a, 22
Between 2b, a specified voltage, for example, 500 V is applied at the peak value of the DC voltage or the sine wave AC voltage of 50 or 60 Hz. In practice, the applied voltage is gradually increased to a specified voltage in about 5 seconds, and is maintained for 1 minute. Then, the presence or absence of abnormalities such as mechanical damage, flashover, and breakdown is observed. In this case, an evaluation test of the withstand voltage of the solder resist 15 is also performed at the same time.

Finally, as an evaluation test of the conductor adhesion, a conductive pattern 23a which is a conductor of the evaluation pattern 23 is used.
For 23b, the peel strength is measured using a tensile tester. Here, the standard value is, for example, 1.0 kN / m or more in the case of a paper phenol resin substrate 11, and the conductor peeling strength is, for example, a crosshead speed of 50 m.
It is measured by a tensile tester that can hold constant between m / min. Then, after peeling off one end of the conductive pattern 23a or 23b to an appropriate length, the substrate 11 is attached to a support portion, and the tips of the peeled conductive patterns 23a and 23b are gripped by a gripping tool, and the copper foil surface Continuously peel 25 mm or more in the vertical direction at a speed of 50 mm / min.

According to the printed wiring board 10 of the present embodiment, by preparing one printed wiring board 10, the reliability of the punching and the reliability of the wiring portion are evaluated, and the reliability of the punching is evaluated. For the evaluation, an accurate reliability evaluation taking into account the influence of stress in the manufacturing process is performed. That is, according to the present embodiment,
By being manufactured in the same manner as a normal printed wiring board, an evaluation pattern for evaluating reliability of punching in at least one region is punched, so that stress in a manufacturing process, for example, thermal stress during punching Dimensional errors will occur due to elastic shrinkage of the punched holes, heat shrinkage, etc. Therefore, the reliability of the punching performance, such as the hole diameter, the hole position, and the outer shape punching accuracy, which takes into account the effects of stress in the manufacturing process, is evaluated. is there.

It should be noted that the conditions of each of the above evaluation tests are merely examples, and the present invention is not limited to these. It is apparent that other test conditions may be employed.

In the above-described embodiment, each of the evaluation patterns 21 to 23 has been exemplified with respect to the shape, and it is obvious that any other shape is used. The dimensions of the evaluation patterns 21 to 23 are appropriately adjusted based on the result of the reliability evaluation test in preparation for the next reliability evaluation test.

[0025]

As described above, according to the present invention, it is possible to accurately evaluate the reliability of punching and to evaluate the reliability of a wiring portion. A substrate can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a printed wiring board for reliability evaluation configured according to the present invention.

2A is a partially enlarged perspective view showing an evaluation pattern for evaluating reliability of punching property in the printed wiring board of FIG. 1, and FIG.

3 (A) is a plan view, FIG. 3 (B) is a partially enlarged plan view, and FIG. 3 (C) is a cross-sectional view taken along the line BB, showing an evaluation pattern for evaluating insulation and withstand voltage in the printed wiring board of FIG. 1; It is.

FIG. 4 is a schematic view sequentially showing a manufacturing process of the printed wiring board of FIG. 1;

[Explanation of symbols]

10 ... printed wiring board, 11 ... board, 12,
13, 14: pattern area, 15: solder resist, 16: component hole, 20: wiring part, seventh area, 21, 22, 23 ... evaluation pattern.

Claims (2)

[Claims] 1. A printed wiring board having a substrate and a wiring portion formed by a conductive pattern formed on the substrate, wherein the substrate has a plurality of different types of evaluation pattern regions. A printed wiring board for reliability evaluation, wherein at least one of the regions has a pattern suitable for reliability evaluation of punching performance. 2. The printed wiring for reliability evaluation according to claim 1, wherein the areas of the plurality of evaluation patterns include a pattern for reliability evaluation on a wiring portion of the printed wiring board. substrate.