JP2009021401A - Printed wiring board and inspecting method for printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board and an inspecting method for printed wiring board such that matching precision of all layers including an internal-layer conductive pattern can be confirmed through single-time inspection after multilayering, and a deviation amount of an arbitrary layer can be digitized at the same time. <P>SOLUTION: Provided is an inspection coupon comprising a conductor and lands formed on both upper and lower sides of the conductor at nearly the same horizontal positions. With this configuration, the matching precision of the conductor and upper and lower lands can be measured through X-ray inspection. Further, the X-ray inspection is carried out for the inspection coupon comprising the dedicated conductor and lands, so the shape and size of the lands can be freely designed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a printed wiring board used for various electronic devices such as a personal computer, a mobile communication telephone, and a video camera, and a printed wiring board inspection method.

  In recent years, as electronic devices have higher functionality and higher density, the electronic components that make up electronic devices are becoming increasingly smaller, more integrated, faster, and more functional. For this reason, various forms of printed wiring boards have been proposed and put into practical use.

  In particular, a through-hole is required for drilling and metal plating because the technology for stacking and integrating the conductive paste directly after filling the adhesive layer that adheres the inner layer substrate and copper foil when multilayering is established. Thus, any layer can be electrically connected by IVH (inner-stitial via hole).

  A method for manufacturing the above-described conventional printed wiring board will be described below. 6A to 6J are cross-sectional views illustrating a conventional method for manufacturing a printed wiring board.

  First, as shown in FIG. 6 (a), films 2 such as PET (polyethylene terephthalate) are laminated on both sides of the prepreg 1, and vias 3 are formed thereon by drilling or carbon dioxide laser processing as shown in FIG. 6 (b). . Next, as shown in FIG. 6C, the via 3 is filled with the conductive paste 4 as a conductor by a method such as printing, and then the film 2 is peeled off from the prepreg 1 to show in FIG. 6D. Thus, the prepreg 1 in which the conductive paste 4 is filled in the via 3 is obtained. Then, as shown in FIG. 6 (e), the copper foils 5 are arranged on both surfaces thereof and heated and pressed by hot press to obtain FIG. 6 (f). Thereafter, the conductive patterns 6 are formed on the copper foils 5 by etching or the like. The double-sided substrate formed as shown in FIG. 6G is completed. The double-sided substrate thus completed is used as an inner layer core substrate, and as shown in FIG. 6H, separately from the inner layer core substrate, the same procedure as shown in FIGS. 6A to 6D above. The prepreg 1 filled with the conductive paste 4 is disposed in the via 3 manufactured by the method described above, and the copper foil 5 is disposed on the outside, and then heated and pressurized by a hot press to obtain FIG. 6 (i). A conductive pattern is formed on the copper foil 5 by etching or the like to complete a printed wiring board which is a four-layer substrate shown in FIG. It is also possible to produce a printed wiring board having six or more layers by repeating the procedure of FIGS. 6H to 6J using the completed four-layer substrate as a core substrate.

  In the printed wiring board configured as described above, when the via 3 is misaligned with respect to the conductive pattern 6, appropriate electrical continuity cannot be obtained between the conductive patterns 6 of different layers, or there is a problem in the initial state. Even if there is not, the problem that it is inferior to long-term reliability occurs. Therefore, it is very important to ensure the matching accuracy between the conductive pattern 6 and the via 3, and it can be said that it is equally important to establish an inspection method for accurately inspecting the matching accuracy.

  Conventionally, the matching accuracy is inspected by observing the printed wiring board from the surface portion and confirming whether or not the via 3 that should originally be hidden under the conductive pattern 6 protrudes from the conductive pattern 6. It was. As shown in FIG. 7, when the via 3 appears to protrude from the land provided at the tip of the conductive pattern 6a, it is determined as defective. In the case of a multilayer printed wiring board, the inspection must be performed on the inner layer substrate. As an observation method, a method performed by a person using a magnifying glass or a microscope is also common, but a method of recognizing an appearance with an appearance inspection apparatus and detecting a defective portion in comparison with a good product stored in advance is also possible. Widely used.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2001-237550 A

  However, in the above-mentioned conventional printed wiring board, since the inspection of the matching accuracy between the via and the conductive pattern is performed by observation from the surface, the inspection must be performed for each layer. And has the problem of increasing the production lead time. Further, it is based only on the determination of the presence or absence of protrusion from the via conductive pattern, and there is a problem that the amount of deviation cannot be quantified.

  The present invention solves the above-mentioned conventional problems, and the accuracy of matching of all layers including the inner conductive pattern portion can be confirmed by a single inspection after multilayering, and at the same time, the amount of deviation of any layer can be numerically determined. It is an object of the present invention to provide a printed wiring board that can be manufactured and a printed wiring board inspection method.

  In order to achieve this object, the printed wiring board of the present invention has an inspection coupon comprising a conductor and lands formed on the upper and lower sides of the conductor so that the horizontal position of the conductor is substantially the same position. Yes. With this configuration, the matching accuracy between the conductor and the upper and lower lands can be measured by X-ray inspection. Moreover, since the X-ray inspection is performed on an inspection coupon made up of a dedicated conductor and land, the shape and size of the land can be designed freely.

  In the printed wiring board of the present invention, the lands connected to both sides of the conductor are both circular and have different configurations. With this configuration, the lands connected to both sides of the conductor do not overlap or cross each other in the X-ray image, and a recognition error occurs when recognizing the circumferential portion of each land. It does not occur, and the matching accuracy between the conductive pattern and the conductor can be accurately detected with high accuracy. Further, it is possible to recognize which land is formed on which layer according to the size of the land.

  In the printed wiring board of the present invention, the lands connected to both sides of the conductor are both regular polygons, and have different sizes and similar shapes. With this configuration, the lands connected to both sides of the conductor do not overlap or intersect with each other in the X-ray image, and a recognition error occurs when recognizing the periphery of each land. In other words, the matching accuracy between the conductive pattern and the conductor can be detected with high accuracy. Further, it is possible to recognize which land is formed on which layer according to the size of the land.

  Moreover, the printed wiring board of this invention has the structure that one side is circular and the other is a regular polygon. With this configuration, it is possible to recognize which land is formed on which layer depending on the shape of the land.

  Further, the printed wiring board of the present invention includes at least one conductor disposed on each insulating layer, and lands formed on the upper and lower sides of each conductor so that the horizontal position of the conductor is substantially the same position. A plurality of inspection coupons, and the inspection coupons are arranged in a certain area. With this configuration, an X-ray inspection is performed in a certain area after the completion of the multilayer printed wiring board, whereby any combination of conductors and lands adjacent to the upper and lower sides can be inspected. There is no need to check the condition.

  Moreover, the printed wiring board of this invention has a test | inspection coupon which consists of a conductor and the land formed so that a horizontal position may become a substantially identical position with a conductor in one of the upper and lower sides of a conductor. With this configuration, the matching accuracy between the conductor and one of the upper and lower lands can be measured by X-ray inspection. Moreover, since the X-ray inspection is performed on an inspection coupon made up of a dedicated conductor and land, the shape and size of the land can be designed freely.

  According to the printed wiring board and the printed wiring board inspection method of the present invention, it is possible to confirm the matching accuracy of all layers including the inner conductive pattern portion by one inspection after multilayering, and at the same time, the amount of deviation of any layer The direction of misalignment can be quantified.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view and an X-ray image of a printed wiring board according to Embodiment 1 of the present invention, and shows an inspection coupon for inspecting the matching accuracy between a land and a conductor. The outline of the process flow for producing the printed wiring board of the present invention is the same as the conventional method for producing a printed wiring board described with reference to FIG. In FIG. 1A, an inspection coupon 14 applied to the printed wiring board of the present invention includes conductors 12a to 12c formed on an insulating layer 13, and lands 11a to 11f formed on conductive layers adjacent to the upper and lower sides of the insulating layer. It is constituted by. The conductors 12a to 12c are obtained by filling a through-hole formed in the insulating layer 13 with a conductive paste and curing by heating and pressing. The lands 11a to 11f are formed in a predetermined shape by etching the conductive layer. Here, a circular example is shown. The centers of the conductor 12a and the lands 11a and 11b adjacent to the top and bottom of the conductor 12a are designed to have the same horizontal position, and the conductor 12a and the lands 11a and 11b constitute a pair of inspection coupons 14. is doing. Similarly, the conductor 12b, the lands 11c, 11d and the conductor 12c, the lands 11e, 11f constitute separate inspection coupons 14, respectively.

  When this inspection coupon 14 is irradiated with X-rays, a transmission image shown in FIG. 1B is obtained. Since the conductor 12a and the lands 11a and 11b are designed so that their centers are at the same position, the matching accuracy can be numerically inspected by obtaining the center position of each circle. From this pair of inspection coupons 14, it is possible to confirm two matching precisions, that is, the matching precision between the conductor 12a and the upper land 11a and the matching precision between the conductor 12a and the lower land 11b. It is effective to design the lands 11a and lands 11b so that their diameters are different so that the circumferential portions do not overlap or cross each other. This makes it easy to know which land is in which layer. Each diameter may be appropriately designed in consideration of the ability value of the matching accuracy. In the first embodiment, assuming that the maximum deviation amount is 0.05 mm, the diameter of the conductor 12a is 0.1 mm, and the diameters of the lands 11a and 11b are 0.2 mm and 0.3 mm, respectively. With this configuration, the periphery of the land can be clearly recognized, and the matching accuracy between the conductor and the land can be inspected with high accuracy without causing a recognition error.

  Also, as shown in FIG. 1, a set of inspection coupons 14 including conductors 12a to 12c arranged one by one in each insulating layer 13 and lands 11a to 11f provided above and below the respective conductors 12a to 12c is defined as a group of inspection coupons. It is also effective to arrange them inside. As a result, all combinations of the conductor and the land adjacent thereto are covered in the inspection coupon group. By inspecting this inspection coupon group after multilayering, it is possible to confirm the matching accuracy of all layers including the inner conductive pattern portion by one inspection. Then, by adjusting the size of a certain area, it is possible to image and process all the above combinations within one field of view as shown in FIG.

  What is necessary is just to select suitably about the installation location of the inspection coupon 14 according to the magnitude | size and form of a product. In general, a printed wiring board is composed of a product area and a reinforcing substrate board for reinforcement provided around the product area in order to flow a mounting line for soldering and mounting components. By installing the inspection coupon 14 on the discarded substrate portion, it can be used for inspection for assuring matching accuracy for each product without interfering with the product area. If there is room in the product area, it may be installed in the product area.

  In the first embodiment, the lands 11a to 11f are circular, but the matching accuracy can be similarly inspected by using regular polygons such as regular triangles and squares. Also at this time, by designing the conductors so that the sizes of the upper and lower lands are different, it is possible to prevent the surroundings of the upper and lower lands from overlapping or intersecting in the X-ray image. Furthermore, one of the upper and lower lands can be circular and the other can be a regular polygon, or one can be a regular triangle and the other can be a square.

  Although FIG. 1 shows an example of a four-layer printed wiring board, it is possible to cope with a printed wiring board having five or more layers by forming an inspection coupon 14 on each layer.

  In addition, the conductors 12a to 12c were formed by filling a through hole formed in the insulating layer 13 with a conductive paste and curing by heating and pressing. However, other methods such as a solid conductor in the through hole Even if it is made by a method of press-fitting a conductor or a method of press-fitting a conductor without processing a through-hole in a predetermined portion of an insulating layer, the same configuration as in the first embodiment is used. An effect can be obtained.

(Embodiment 2)
In the first embodiment, it is also effective to connect lands formed in the same layer with a wiring circuit. FIG. 2 shows the land 11b and land 11c, and the land 11d and land 11e formed in the same layer in FIG. Thus, the matching accuracy can be confirmed by X-rays by the same method as described in the first embodiment, and the inspection coupon group is used as a conduction confirmation pattern, and the electrical continuity of the entire inspection coupon group by electrical inspection. Can also be confirmed.

  By adopting the second embodiment, in the electrical inspection process for confirming whether or not there is a disconnection or a short circuit, a misalignment is usually detected by confirming whether there is an abnormality in the electrical resistance value of the inspection coupon group. be able to. An operation method may be used in which only products that are abnormal in the electrical inspection are inspected in more detail by the X-ray inspection.

  As in the first embodiment, the shape of the land can be a circle, a regular polygon, or the like. As shown in FIG. 2B, the lands 11b to 11e have a shape that is partially missing at a portion to which the surrounding wiring circuit 17 is connected, but the center position of the land can be obtained by image recognition.

  For the outermost lands 11a and 11f, it is possible to use a method of providing a lead-out land for contacting an inspection probe in an electrical inspection.

(Embodiment 3)
FIG. 3 is a further development of the second embodiment. Here, the upper and lower lands 11a to 11f of the conductors 12a to 12c are all circles having the same diameter, the width of the wiring circuit 17 is the same as the diameter of the lands 11a to 11f, and the conductors 12a to 12c are connected to the lands installed on one side of the conductor. The wiring circuit 17 and the wiring circuit 17 connected to the land installed on the other side are connected to each conductor in a direction of about 180 °. As a result, the lands on both ends of each wiring circuit 17 have a semicircular shape. The top and bottom lands of the via are originally circular with the same diameter and the same horizontal position, but are connected to the wiring circuit 17 to form a semicircular shape, and the two semicircles are opposite in direction by 180 °. In the X-ray image, the arc portions of the two semicircles are in a positional relationship that does not overlap. As a result, each arc can be clearly recognized, and the center of the original circle can be obtained with high accuracy.

  By making the upper and lower lands circular with the same diameter, it is possible to avoid making the lands larger than necessary. As a result, the area of the entire inspection coupon group can be reduced.

(Embodiment 4)
Next, another form as an inspection coupon will be described. FIG. 4 is a cross-sectional view and an X-ray image of the printed wiring board according to Embodiment 4 of the present invention, and shows another inspection coupon for inspecting the matching accuracy between the land and the conductor. In the fourth embodiment, as shown in FIG. 4A, the inspection coupon 14 is composed of conductors 12a to 12f formed on the insulating layer 13 and lands 11a to 11f formed only on one of the upper and lower sides of the insulating layer. It is configured. As in the first embodiment, the conductors 12a to 12f are obtained by filling a through-hole formed in the insulating layer 13 with a conductive paste and curing by heating and pressing. The lands 11a to 11f are formed in a predetermined shape by etching the conductive layer. The centers of the conductors 12a to 12f and the lands 11a to 11f formed on one of the upper and lower sides of the conductors 12a to 12f are designed to have the same horizontal position, and a pair of inspections is performed by each pair of the conductor and the land. A coupon 14 is configured.

  In the first embodiment, an X-ray image in which two lands having different diameters are overlapped is obtained. Therefore, the smaller land located on the inner side recognizes the circumferential portion based on a subtle difference in shading. In the fourth embodiment, the lands do not overlap each other as shown in FIG. 4B and are arranged separately, and there is an advantage that adjustment of image processing becomes easy.

  The matching accuracy inspection using the inspection coupon 14 may be performed by the same method as in the first embodiment. That is, the center position of each of the lands 11a to 11f and the conductors 12a to 12f is obtained from the transmission image shown in FIG. 4B obtained by irradiating the inspection coupon 14 with X-rays. Can be inspected.

  Also, as shown in FIG. 4, it is composed of two conductors arranged in each insulating layer and lands provided on the upper and lower sides thereof, and one of the two conductors arranged in each insulating layer is a conductor. It is also effective to arrange a set of inspection coupons 14 with a combination of lands formed on the upper side and a combination of conductors and lands formed on the lower side as a group of inspection coupons in a certain area. is there. As a result, all combinations of the conductor and the land adjacent thereto are covered in this inspection coupon group. Then, by adjusting the size of a certain area, it is possible to image and process all the above combinations within one field of view as shown in FIG. This arrangement method can be appropriately selected as a design matter. In FIG. 4B, an example of one horizontal column is shown for convenience of explanation, but the present invention is not limited to this, and other arrangements such as 2 rows and 3 columns are also possible.

(Embodiment 5)
The printed wiring board of the fifth embodiment is a collective printed wiring board constituted by a plurality of individual printed wiring boards. In the mounting process for soldering components such as IC chips, it is common to use individual printed wiring boards after the assembly printed wiring board is divided by cutting, but in the manufacturing process of printed wiring boards, the efficiency is high. In general, it is processed in a state of a collective printed wiring board for production. When inspection coupons cannot be installed in either the product area or the discarded board part described in the first embodiment, they can be installed between the individual printed wiring boards and in the margins around the printed wiring boards. it can. Assuming a case in which up to a certain stage of the collective printed wiring board is manufactured in-house due to the recent diversification of business forms and then sold to other companies, X-ray inspection is performed after using the above configuration, and each individual print It is also effective to guarantee the wiring board.

  FIG. 5 is a plan view of a printed wiring board according to the fifth embodiment of the present invention. In the collective printed wiring board of a plurality of individual printed wiring boards 16, inspections provided between and around the individual printed wiring boards 16 are provided. The case where an inspection coupon is installed in the coupon area 15 is shown.

  Inspecting the printed wiring board according to the fifth embodiment, after cutting into individual printed wiring boards 16, the inspection coupon area 15 is also removed together with the blank portion. Must be done in the state of a board. By inspecting the inspection coupons installed at the four corners of the individual printed wiring board 16, the individual printed wiring board 16 surrounded by the inspection coupons at the four corners is determined to be non-defective only when the inspection result of the inspection coupon is OK. It can be handled by the operation method.

  Further, when the printed wiring board according to the fifth embodiment of the present invention is used, the whole or a part of the aggregate printed wiring board that is inspected in the state of the aggregate printed wiring board in an appropriately selected processing step and determined to be defective. It is also possible to save useless processing costs by adopting an operation method in which processing is not performed in a subsequent processing step.

  It is also possible to improve the matching accuracy of the product by performing a prior inspection in the middle of the manufacturing process of the printed wiring board in which continuous production is performed and feeding back the inspection result to the manufacturing process. The formation position of the land on the surface layer is determined by the alignment position of the exposure film when the dry film used as the etching resist is exposed. Therefore, by inspecting the inspection coupon after manufacturing the preceding product from the exposure process to etching, the deviation of the land with respect to the conductor is obtained by the X component and the Y component on the two-dimensional plane, respectively, and this result is fed back to the exposure process. If the alignment position of the exposure film is corrected, a product having a high matching accuracy can be produced.

  As described above, according to the printed wiring board and the printed wiring board inspection method of the present invention, the matching accuracy of all layers including the inner layer conductive pattern portion can be quantified and confirmed by a single inspection after multilayering. It is useful for various electronic devices such as personal computers, mobile communication telephones, and video cameras.

The figure which shows sectional drawing and X-ray image of the printed wiring board in Embodiment 1 of this invention The figure which shows sectional drawing and X-ray image of the printed wiring board in Embodiment 2 of this invention The figure which shows sectional drawing and X-ray image of the printed wiring board in Embodiment 3 of this invention The figure which shows sectional drawing and X-ray image of the printed wiring board in Embodiment 4 of this invention The top view of the printed wiring board in Embodiment 5 of this invention Sectional drawing which shows the manufacturing method of the conventional printed wiring board The figure which shows the inspection method of the conventional printed wiring board

Explanation of symbols

11a to 11f Land 12a to 12f Conductor 13 Insulating layer 14 Inspection coupon 15 Inspection coupon area 16 Individual printed wiring board 17 Wiring circuit

Claims (14)

A plurality of conductive layers, insulating layers alternately stacked with the conductive layers, and a conductor that penetrates the insulating layers and electrically connects the conductive layers,
A printed wiring board comprising: an inspection coupon including the conductor and lands formed on both upper and lower sides of the conductor so that the horizontal position of the conductor is substantially the same. The printed wiring board according to claim 1, wherein the lands connected to both sides of the conductor are both circular and have different diameters. 2. The printed wiring board according to claim 1, wherein the lands connected to both sides of the conductor are both regular polygons, different in size and similar in shape. 2. The printed wiring board according to claim 1, wherein one of the lands connected to both sides of the conductor is circular and the other is a regular polygon. A plurality of conductive layers, insulating layers alternately stacked with the conductive layers, and a conductor that penetrates the insulating layers and electrically connects the conductive layers,
A plurality of inspection coupons comprising at least one conductor disposed on each of the insulating layers, and lands formed on both upper and lower sides of each of the conductors so that the horizontal positions of the conductors are substantially the same. Having a configured inspection coupon group,
The printed wiring board, wherein the inspection coupons are arranged in a certain area. 6. The printed wiring board according to claim 5, wherein the lands formed in the same layer among the lands of the inspection coupon in the same area are connected by a wiring circuit. The lands in the same area are circular with the same diameter,
The width of the wiring circuit that connects the lands formed in the same layer in the same area is the same as the diameter of the lands,
The wiring circuit connected to one land of the conductor and the wiring circuit connected to the other land of the conductor are connected in substantially opposite directions from the conductor, respectively. The printed wiring board according to claim 6. A plurality of conductive layers, insulating layers alternately stacked with the conductive layers, and a conductor that penetrates the insulating layers and electrically connects the conductive layers,
A printed wiring board comprising: an inspection coupon comprising a conductor and a land formed on one of upper and lower sides of the conductor so that the horizontal position of the conductor is substantially the same. A plurality of conductive layers, insulating layers alternately stacked with the conductive layers, and a conductor that penetrates the insulating layers and electrically connects the conductive layers,
A plurality of inspection coupons comprising at least two conductors arranged on each of the insulating layers, and lands formed on the upper and lower sides of each of the conductors so that the horizontal positions of the conductors are substantially the same. A test coupon group configured by
An inspection coupon consisting of a combination of the conductor and a land formed above the conductor and an inspection coupon consisting of a combination of the conductor and a land formed below the conductor disposed on each of the insulating layers. Including
The printed wiring board, wherein the inspection coupons are arranged in a certain area. The printed wiring board according to claim 1 or 8, wherein the inspection coupon is disposed on a discarded substrate portion formed around or part of the periphery of the product area. The printed wiring board according to claim 1, wherein the inspection coupon is arranged in a product area. 9. The print according to claim 1, wherein the print coupon is configured by a set of a plurality of individual printed wiring boards, and an inspection coupon is disposed between or around the individual printed wiring boards outside the area of the individual printed wiring boards. Wiring board. The printed wiring board according to claim 12, wherein inspection coupons are arranged at four corners of the individual printed wiring board. The center of each land and via is obtained from a transmission image obtained by irradiating the inspection coupon of the printed wiring board according to claim 1 or 8 with X-rays, and the matching accuracy between the land and the via is confirmed by the difference. A method for inspecting a printed wiring board, comprising:

Images