JP4003512B2 - MULTILAYER WIRING BOARD, SUBSTRATE STRUCTURE COMBINING A MULTIPLE WIRING BOARD AND METHOD OF USING THE SAME - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer wiring board used for inspection of a processed state of a multilayer substrate after laser processing, a substrate structure in which a plurality of multilayer wiring substrates are combined, and a method of using them.
[0002]
[Prior art]
On the multilayer wiring board, wiring corresponding to the target circuit configuration is mounted and formed on each internal layer. The circuit characteristics are changed or set after the inner layer wiring is mounted by changing the shape such as cutting the wiring. Laser processing technology is used for such a minute shape change for the wiring. In order to enable a minute shape change to the wiring, it is required that the laser output conditions be set appropriately. The setting of the laser output conditions so far is performed on a trial basis for a large number of multilayer wiring boards which are actual products. The wiring state of each of a number of laser-processed multi-layer wiring boards is inspected by the operator's visual inspection. For the visual inspection, it was necessary to cut the processed substrate, peel the substrate surface layer, or polish the exposed portion of the laser beam in the inner layer wiring. .
[0003]
[Problems to be solved by the invention]
In the above, it takes a considerable time to process the laser-processed multilayer wiring board so that visual inspection or the like can be easily performed, and it takes time and effort to become inspectable. Since the laser-processed part is also affected by the process of exposing the substrate to the outside of the visual inspection part, it is difficult to accurately check the laser-processed state. Since laser processing and inspection processing are performed on an actual product substrate, the cost is high.
[0004]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a multilayer wiring board that can easily determine the laser processing state for inner layer wiring and a method of using the multilayer wiring board. Yes.
[0005]
[Means for Solving the Problems]
A first multilayer wiring board according to the present invention is a multilayer wiring board in which wiring is provided in an inner layer, and the wiring is provided with an inspection target portion to be processed by a laser, and is irradiated with a laser. An opening for visual inspection reaching the inspection target part is formed on the other surface opposite to the one surface serving as the side.
[0006]
The inspection target portion refers to a laser processing portion on the inner layer of the product substrate and a laser processing target portion having a simulated configuration in, for example, thickness and shape.
[0007]
According to the first multilayer wiring board, since the opening reaching the inspection target portion of the inner layer wiring is formed in advance, after the laser processing is performed on the inspection target portion, the visual inspection of the processing state is performed. It will be possible immediately through. Since it is not necessary to perform processing to make the processing portion visible after processing by the laser, it is possible to perform a visual inspection more accurate than in the past. The visual inspection can immediately determine the quality of the laser processing. Based on the determination result, the laser processing conditions can be confirmed, and the laser processing conditions for the actual product can be set. Therefore, the inspection work efficiency is improved. In addition, it is not necessary to use a large amount of an actual product substrate for testing, so that the cost can be reduced.
[0008]
In the first multilayer wiring board, an inspection terminal portion having one end connected to the inspection object portion is provided, and the inspection terminal portion is pulled out to the outside, and the other end portion is on the substrate surface. A derived configuration may be added .
[0009]
The terminal part for inspection is derived from the inner layer to the external substrate surface so as to be connected to an inspection device for inspecting the electrical characteristics of the inspection target part, and the other end is connected to the inspection target part. This includes the parts that have been derived to the outside.
[0010]
According to the multilayer wiring board having the configuration in which the inspection terminal portion is added, the laser processing is performed on the inspection target portion, and then the laser is detected by detecting the electrical characteristics of the inspection target portion through the inspection terminal portion. The quality of processing can be judged immediately. Based on the determination result, the laser processing conditions can be confirmed, and the laser processing conditions for the actual product can be set. Therefore, the inspection work efficiency is improved. In addition, since it is not necessary to use a large amount of the product substrate for testing, the cost can be reduced.
[0013]
In the present invention, it is preferable that a plurality of multilayer wiring boards are provided, and each of the boards is integrally arranged along the surface direction. In this case, laser processing can be performed for each of a plurality of multilayer wiring boards with different conditions. Thereby, the conditions of laser processing can be quickly determined by inspecting the processing state on each substrate and comparing the states with each other.
[0014]
The method for using the first multilayer wiring board of the present invention includes a step of processing the inspection target portion with a laser, and a visual inspection through the opening of the processing state of the inspection target portion after the processing. It is preferable to have a process. In this case, since processing such as laser cutting is performed on the inspection target portion, and then the processing state is visually inspected through the opening, the opening is not separately formed after the laser processing. Therefore, the inspection work can be speeded up and work efficiency can be improved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the details of the present invention will be described with reference to the drawings.
[0017]
1 to 5 show an example of an embodiment of a multilayer wiring board according to the present invention, and FIG. 1 is a plan view showing an outline of a large-sized board structure in which a plurality of multilayer wiring boards are combined together. FIG. 3 is a plan view showing a wiring pattern of an inner layer of one multilayer wiring board in FIG. 1, FIG. 3 is a longitudinal sectional view showing an essential part of one multilayer wiring board in FIG. 1, and FIG. FIG. 5 is an enlarged plan view showing an inspection target portion of the multilayer wiring board, and FIG. 5 is a flowchart showing a process of manufacturing the multilayer wiring board shown in FIG.
[0018]
Referring to FIG. 1, the large substrate structure 1 is formed as an assembly of small multilayer wiring substrates 2. The large-sized substrate structure 1 is an integrated state in which a plurality of rectangular wiring boards 2 having a rectangular shape in plan view are arranged in a vertical and horizontal direction along the plate surface direction. Each multilayer wiring board 2 is formed by laminating a large number of insulator layers as will be described later. Referring to FIG. 2, a predetermined inner layer 4 of each multilayer wiring board 2 is provided with a wiring pattern 5 as a wiring. Each multilayer wiring board 2 is provided with inspection terminal portions 3 and 3 exposed to the outside at two diagonal positions of the four corners of the substrate surface. A pair of electrode portions 3a, 3a provided at the end of the wiring pattern 5 formed in the inner layer 4 and the inspection terminal portion 3 exposed to the outside are connected to each other through a via hole (not shown). .
[0019]
The wiring pattern 5 includes a wiring path portion 5a connected to the inspection terminal portions 3 and 3, and an inspection target portion 7 connected to the inspection terminal portions 3 and 3 through the wiring path portion 5a. There are 24 inspection object portions 7 which are cutting parts by laser. The line width of the inspection object portion 7 is configured to be about 3 to 4 times wider than the wiring path portion 5 a in the wiring pattern 5. A set of 12 inspection target portions 7 having a rectangular shape in plan view arranged in a vertically long posture to form one group G1 is formed at the central portion in the left-right direction of the multilayer wiring board 2. A group G2 is formed by arranging six rectangular inspection object portions 7 in a horizontally long posture on each of the left and right sides of the group G1. All the inspection object portions 7 are connected in parallel to both inspection terminal portions 3 and 3. One end side of both inspection terminal portions 3 and 3 is connected to each inspection object portion 7 through the wiring path portion 5a. The inspection terminal portions 3 and 3 are led to the substrate surface so as to be exposed to the outside through the wiring path portion 5a, the electrode portion 3a, and the via holes.
[0020]
With reference to FIG. 3, openings 8 are formed in a drawn-out state from the surface layer on the back surface side of the multilayer wiring board 2 to all the inspection object portions 7. As shown in FIG. 4A, the opening 8 may be formed in a rectangular shape that is larger in plan view than the inspection target portion 7 that is rectangular in plan view. As shown in FIG. 4B, the opening 8 may be formed so that a portion corresponding to a laser processing portion to be described later in the inspection target portion 7 is exposed to the outside through the back surface of the substrate. In the case shown in FIG. 4B, the opening 8 is drawn out in a circular shape in plan view, and the openings 8 are not formed up to the four corners of the inspection target portion 7 having a rectangular shape in plan view. Each inspection object part 7 is visually observed by a worker through the opening 8.
[0021]
Next, the manufacturing method of this large sized substrate structure 1 is demonstrated according to FIG. First, in step S1, the glass cloth wound around the roll is impregnated with a resin liquid (in this case, an epoxy resin) while being fed out of the roll. In step S2, the glass cloth impregnated with the resin liquid is dried. A prepreg is formed by obtaining this drying step. This prepreg is cut into a predetermined rectangular plate shape. In step S3, a copper clad laminate is produced by laminating and bonding a copper foil to the surface of the prepreg. In step S4, an inner wiring pattern is formed on the copper-clad laminate. In step S5, the wiring pattern is etched. This etched prepreg is obtained as an inner layer copper clad laminate. Apart from the step of obtaining the inner layer copper-clad laminate, in step S6, the prepreg is laminated in the required number of layers to produce a front side laminate and a back side laminate. In step S7, the inspection-side terminal portions 3 and 3 are patterned on the upper surface of the laminate for producing a surface-side laminate, whereby the surface-side laminate is produced. In step S8, the front side laminate, the inner layer copper clad laminate, and the rear side laminate are laminated and pressure-bonded with the inner layer copper clad sandwiched therebetween, thereby producing a laminate. . In step S <b> 9, a hole corresponding to the opening 8 is drilled in a corresponding position of the inspection target portion 7 of the wiring pattern 5 with respect to the back surface side of the laminated plate by a processing tool such as an end mill. The drilling depth is adjusted so as to coincide with the inspection target portion 7. Thereby, the inspection object part 7 is exposed to the outside through the opening part 8. In step S10, via holes (not shown) for electrically connecting the electrodes 3a, 3a of the wiring pattern 5 of the inner layer 4 and the inspection terminal portions 3, 3 on the surface of the substrate are formed in the laminated plate, and a conductive material such as a conductive paste is formed. Embed the material in the via hole. Thereby, the production of the large substrate structure 1 is completed.
[0022]
Next, a method for using the large substrate structure 1 will be described. The large substrate structure 1 is fixedly mounted on an XY table of a laser processing apparatus. At this time, since laser processing is performed from the surface side of the large substrate structure 1, the surface of the large substrate structure 1 is directed to the laser source side. Based on a preset processing program, cutting processing is performed with a laser for each multilayer wiring board 2 while processing position adjustment is performed on an XY table. In this case, a cutting process is performed so that each inspection object part 7 is disconnected through an insulating layer made of glass epoxy resin. Laser processing is performed in a state where conditions such as laser output and irradiation time are appropriately changed for each multilayer wiring board 2. In FIG. 2, a portion indicated by a broken line is a portion where cutting by laser is performed, and the directionality of the processing is indicated by an arrow.
[0023]
When the processing by the laser on the inspection target portions 7 of all the multilayer wiring boards 2 is completed, the inspection process is performed next. First, an inspection process for inspecting electrical characteristics will be described. The processed large substrate structure 1 is mounted on an inspection table (not shown) of an inspection apparatus. Next, the pair of measurement probes of the inspection apparatus is brought into contact with the inspection terminal portions 3 and 3 of the multilayer wiring board 2 selected as the measurement target. The inspection apparatus executes a test of the conduction state between the measurement probes by outputting a measurement signal between the measurement probes. If all the 24 inspection target portions 7 of the multilayer wiring board 2 are cut well by laser processing, the measurement signal does not flow between the pair of measurement probes. Judged to be good. When the measurement signal flows between the pair of measurement probes in the inspection, the inspection apparatus determines that the cutting is not performed by at least one characteristic check. The inspection result information for each multilayer wiring board 2 is recorded and held in a control device (not shown) of the inspection device.
[0024]
Next, each inspection target unit 7 is displayed on a monitor using an imaging unit (not shown) capable of macro imaging, and a visual inspection is performed on the displayed inspection target unit 7. In this case, with respect to those having good electrical characteristics in the previous inspection, the cut state of the cut portion, the formation state of the flash, etc. are visually inspected. Thereby, it is judged by visual observation of a specific shape state whether or not the state of the laser-cut cutting portion is good. This visual inspection may be automatically performed by image processing instead of the human visual inspection.
[0025]
Therefore, it can be determined by electrical property inspection and visual inspection whether the processing state when the laser processing conditions are changed in various ways is improved from what was processed. Based on the test result of the multilayer wiring board, various conditions at the time of laser processing for an actual product can be easily set. That is, for example, when the laser output is processed by changing the laser output during processing stepwise, the laser output that can be processed can be set as the minimum laser output that can be processed.
[0026]
The present invention is not limited to the above-described embodiments. For example, the following modifications and application examples are possible.
[0027]
(1) The process of cutting only a part of the wiring pattern of the inner layer is performed with a laser, for example, without cutting so as to break the inspection target portion of the wiring pattern of the inner layer with a laser. The present invention can be applied to a device for examining a mechanical characteristic such as an impedance characteristic.
[0028]
(2) Instead of a large substrate structure in which a plurality of substrates are integrally arranged vertically and horizontally, a multilayer wiring substrate may be configured with only a single substrate.
[0029]
(3) The multilayer wiring board is not limited to the one having both the opening portion drilled to the inspection target portion and the inspection terminal portion, and may have only the opening portion .
[0030]
(4) The present invention includes one in which at least one inspection object portion to be laser processed is provided in the inner layer of one multilayer wiring board.
[0031]
(5) The multilayer wiring board according to the present invention may be a multilayer wiring board in which ceramic substrates are multilayered and a conductor pattern formed on the inner layer.
[0032]
(6) In the method of manufacturing a multilayer wiring board, the multilayer wiring board is formed without an opening with a wiring pattern on the inner layer, and then the opening is drilled with an end mill or the like. Alternatively, a multilayer wiring board may be formed by laminating a prepreg having an opening formed in advance and a prepreg having a wiring pattern.
[0033]
More specifically, apart from the step of obtaining the inner layer copper clad laminate, the back side laminate is produced by laminating the required number of prepregs. A through-hole corresponding to the opening is formed in the corresponding position of the inspection target portion by a processing tool such as an end mill with respect to the back side laminated plate. In addition, the prepreg is laminated in the required number of layers separately from the back side laminate, and the front side laminate having the inspection terminal portion on the surface is produced. Next, the front surface side laminated plate, the inner layer copper clad laminated plate, and the back surface side laminated plate are laminated and pressure-bonded in a state where the opening portion and the inspection target portion are aligned. Thereby, a desired multilayer wiring board is produced. When this lamination is performed, the inner layer wiring pattern is exposed to the outside from the opening.
[0034]
【The invention's effect】
According to the present invention, after the processing by the laser is subjected to the inspection target portion, whether the processing status is how, visual inspection of the through openings is immediately available for inspection target portion . Since it is not necessary to use a large amount of the product substrate for testing, the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a multilayer wiring board according to the present invention. FIG. 2 is a plan view of the multilayer wiring board. FIG. 3 is a schematic plan view showing a multilayer wiring board made into a large board. FIG. 5 is a flow chart showing the manufacturing process of a multilayer wiring board.
DESCRIPTION OF SYMBOLS 1 Multilayer wiring board 2 Board | substrate 3 Inspection terminal part 4 Inner layer 5 Wiring pattern (wiring)
7 Inspection target part 8 Opening part

Claims (4)

  The wiring is a multilayer wiring board provided in an inner layer, and the wiring is provided with an inspection target portion to be processed by a laser, on the side opposite to one side which is a laser irradiation side An opening for visual inspection reaching the inspection target part is formed on the other surface of the multilayer wiring board. In the multilayer wiring board according to claim 1,
The inspection and the inspection terminal portions connected to one end thereof is provided to the target unit, the inspection terminal portions, and wherein the other end portion is guided to the substrate surface, it order to bring out to the outside Multilayer wiring board. 3. A substrate structure comprising a plurality of the multilayer wiring boards according to claim 1 or 2 , wherein each of the boards is integrally arranged along the surface direction. In the usage method of the multilayer wiring board of Claim 1 or 2 ,
A step of processing the inspection target portion with a laser;
And a step of visually inspecting the processed state of the inspection target portion through the opening after the processing.

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