JP3996432B2 - Multilayer printed wiring board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer printed wiring board provided with a plurality of individual wiring boards, and more particularly to a multilayer printed wiring board capable of easily specifying the presence or absence of an inner layer defect for each individual wiring board.
[0002]
[Prior art]
A typical method for confirming the failure of a printed circuit in a printed wiring board is a continuity checker that confirms the continuity of the front and back wiring circuits. In the confirmation, the continuity checker may not be used for the following reasons.
[0003]
For example, when forming electrolytic gold plating on solder connection pads, when connecting each pad with a plating lead, or when multiple wiring circuits use the solid pattern of the inner layer as a common pattern, etc. This is because, if the continuity checker is performed, it is determined that the short state occurs between the pads and between the wiring circuits.
[0004]
[Problems to be solved by the invention]
Therefore, in the above cases, defective product management was performed by recording the portion of the inner wiring circuit that was determined to be defective in the appearance inspection on paper, and therefore countermeasures against defective product leakage were insufficient. There was a concern that defective products would be mixed into the product.
In addition, the printed wiring board is generally manufactured in the form of a sheet in which a plurality of individual wiring boards are arranged, and in order to avoid the above-mentioned concerns, if a defect occurs in the individual wiring board, the sheet is defective. However, in the package substrate, each individual wiring board is very small, and a large number of individual wiring boards are arranged on the sheet. There was a problem of being very low.
[0005]
The present invention has been made to solve the above-described problems, and the object of the present invention is as a method for confirming the failure of the inner layer wiring circuit without requiring a continuity checker and easily determining whether there is an inner layer wiring circuit failure. An object is to provide a multilayer printed wiring board that can be specified for each board.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention according to claim 1 has a confirmation pattern in which the presence or absence of an inner layer wiring circuit defect can be specified for each individual wiring board and can be visually confirmed from the outer layer, and all the insulating layers are A multilayer printed wiring board including a plurality of individual wiring boards made of a material that can pass through the wiring circuit on the back side, and the confirmation pattern includes a plurality of individual pads corresponding to the individual wiring boards. The inner layer on the surface side of the individual pad is checked with respect to one individual wiring board while checking the presence or absence of the inner layer wiring circuit defect by the presence or absence of the individual pad due to deletion by a sharp one and the surface side check pads blackened indicating the presence or absence of the wiring circuit failure, and characterized by comprising a rear surface side check pad indicating the presence or absence of inner wiring circuit failure in the back side That is a multi-layer printed wiring board.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the present invention will be described using a multilayer printed wiring board for one sheet shown in FIG.
FIG. 2 (e) is a plan view of the front surface side of the multilayer printed wiring board 1 of the present invention, 30 individual wiring boards 2 having 10 columns and 3 rows, and formed on the inner layer and can be confirmed from the outer layer. The confirmation pattern 3 includes a front-side confirmation pad 3a for indicating the presence or absence of an inner-layer wiring circuit defect on the front surface side of the individual inner-layer wiring board 2a, and an inner-layer wiring on the back surface side of the individual inner-layer wiring board 2a. The back side confirmation pad 3b for indicating the presence or absence of a circuit defect is formed corresponding to the three individual wiring boards 2 formed on each confirmation pattern 3, and corresponds to the defective portion of the individual inner layer wiring board 2a. Thus, the pad 3a or 3b is removed.
[0011]
Next, the manufacturing process of the multilayer printed wiring board 1 shown in FIG. 2 (e) will be described with reference to FIGS. 1 and 2, and a method for checking an inner layer wiring circuit defect will also be described.
First, a metal foil-clad laminate in which a metal foil such as copper foil is laminated on both sides of an insulating base material (a material through which the wiring circuit on the back side can penetrate) is prepared. By forming 30 individual inner layer wiring boards 2a composed of three rows and a confirmation pattern 3 displayed corresponding to each column in the vicinity of the individual inner layer wiring board 2a, FIG. The inner layer printed wiring board 1a is obtained. The confirmation pattern 3 is formed on the surface of the individual inner layer wiring board 2a, formed on the surface side confirmation pad 3a indicating the presence or absence of an inner layer wiring circuit defect on the surface side, and on the back surface of the individual inner layer wiring board 2a. The back side confirmation pad 3b which shows the presence or absence of the inner-layer wiring circuit defect in this can be confirmed from the surface side through the insulating base material. Thereby, both confirmation pads 3a and 3b can be easily confirmed from one side (here, the front side). Next, an appearance inspection of the inner layer printed wiring board 1a of FIG. 1A is performed to check whether there is an inner layer wiring circuit defect in the individual inner layer wiring board 2a, and at the position where the detected defective individual inner layer wiring board 2a is located. The corresponding front side confirmation pad 3a or back side confirmation pad 3b is deleted with a sharp object, for example, a cutter (see FIG. 1B). The number displayed on the upper part of the confirmation pattern 3 indicates the number of each row of the individual inner wiring board 2a. For example, in the first column of FIG. Since 1 and 2 of 3a are deleted, it is said that a defect has occurred in the surface side wiring circuit of the first row and the second row in the first column of the individual inner layer wiring board 2a group formed on the inner layer printed wiring board 1a. You can confirm that. Next, the inner layer printed wiring board 1a in FIG. 1C in which the metal foil surface is roughened by applying a roughening process such as a blackening process to the inner layer printed wiring board 1a in FIG. obtain. As a result, the color of the front side confirmation pad 3a becomes darker and the back side confirmation pad 3b does not change color (because the back side confirmation pad 3b is transmitted through the insulating base material of the pad 3b). It is possible to confirm more clearly on which side the defect has occurred, and prevent misidentification of the front and back surfaces when conducting a retrospective investigation of the cause of the defect. Next, as shown in FIG. 2 (d), metal foils are laminated on the front and back through an interlayer insulating layer (a material through which the inner layer wiring circuit can pass), and a plurality of individual wiring boards 2 are formed by a general subtractive method. The wiring circuit is formed and the metal foil present on the confirmation pattern 3 is removed. Through the above-described steps, the multilayer printed wiring board shown in FIG. 2E is obtained in which the defective portion of the individual inner wiring board 2a can be easily confirmed visually from the outer layer.
[0012]
In the description of the present invention, the description has been given using the four-layer printed wiring board for one sheet provided with 30 individual wiring boards. However, the configuration is not limited to this, and the insulating base material for the inner printed wiring board is used. In this case, a material that can be transmitted through the wiring circuit on the back surface is used. However, a material that does not transmit light may be used. In this case, the present invention works effectively if one side is confirmed.
[0013]
【The invention's effect】
By configuring the multilayer printed wiring board according to the present invention, even when the continuity checker cannot be used for the continuity inspection of the inner layer wiring circuit, it is possible to easily check for defective products. Can be avoided and the product yield can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing production steps (a) to (c) of a multilayer printed wiring board of the present invention.
FIG. 2 is a schematic plan view showing manufacturing steps (d) to (e) of the multilayer printed wiring board of the present invention.
[Explanation of symbols]
1: Multilayer printed wiring board 1a: Inner layer printed wiring board 2: Individual wiring board 2a: Individual inner layer wiring board 3: Confirmation pattern 3a: Front side confirmation pad 3b: Back side confirmation pad

Claims (1)

It is possible to specify the presence or absence of inner layer wiring circuit failure for each individual wiring board, and has a confirmation pattern that can be visually confirmed from the outer layer, and all insulating layers are made of a material that can penetrate the wiring circuit on the back side. A multi-layer printed wiring board having a plurality of individual wiring boards, wherein the confirmation pattern includes a plurality of individual pads corresponding to the individual wiring boards, and each of the individual pads is deleted by a sharp one. The presence / absence of the inner layer wiring circuit failure is confirmed by the presence / absence, and the individual pad is blackened to indicate the presence / absence of the inner layer wiring circuit failure on the surface side of one individual wiring board. A multilayer printed wiring board comprising a pad and a back-side confirmation pad indicating the presence or absence of an inner-layer wiring circuit defect on the back side .

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