JP2003273524A - Multilayer printed wiring board and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer printed wiring board whose impact in disconnection is relaxed, and whose cracking quantity is reduced, and to provide a method for manufacturing it. <P>SOLUTION: A multilayer printed wiring board is provided with a plurality of non-through holes at the disconnection scheduled sites of an outermost insulating layer. This method for manufacturing a multilayer printed wiring board comprises a process (a) for molding a multilayer printed wiring board by disposing multilayer insulating layers and multilayer wiring conductive layers, a process (b) for carrying out necessary circuit working, and a process (c) for forming a plurality of non-through holes at the disconnection scheduled sites of the outermost insulating layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a multilayer printed wiring board and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, multilayer printed wiring boards are generally
One or more prepreg sheets obtained by impregnating a glass cloth base material with epoxy resin and semi-cured are stacked on the circuit-formed inner layer circuit board, and then copper foil is stacked on top of the prepreg sheet and heat-molded integrally with a hot plate press. It has been manufactured through the process of doing. However, in recent years, along with thinning and miniaturization of printed wiring boards, build-up wiring boards using an adhesive sheet that does not use glass cloth (with or without metal foil such as copper) Has attracted attention and is used in the manufacture of multilayer printed wiring boards.

[0003]

In the manufacturing process of a multilayer printed wiring board, a plurality of insulating layers and a plurality of wiring conductor layers are vertically stacked on one sheet (carrier sheet) in view of manufacturing efficiency. It is generally practiced to dispose them in a single piece, collectively mold them, cut them, and then process them into an arbitrary size (product size) to be actually used. In the cutting process, the excess part is often scraped off by router processing or the like in advance, and the wiring board is often cut and used after the step of mounting the component on the wiring board. As the cutting means, there are adopted a method of manually folding a joint portion (hereinafter referred to as “rib portion”), a method of punching using a punch or the like, and a method of cutting with a machine such as a cutter.

However, at the stage of actually cutting the wiring board, a crack or the like often occurs in the surface layer of the wiring board due to the impact at the time of cutting. This problem has been highlighted by the recent increase in packaging density and changes in packaging modes such as the CSP method. That is, in the circuit near the outer peripheral portion of the wiring board, there is a concern that the circuit may be broken due to cracks, and the reliability may be reduced. To solve these problems, a method of making a V-shaped cut in the rib portion (generally called “V cut”),
In addition, a method has been adopted in which a through hole is formed in the rib portion with a drill to reduce the area of the rib portion while maintaining the strength to some extent. However, due to the increase in mounting density, the above problems cannot be solved. Furthermore, in order to reduce the roughness of the inner wall of the through hole and to increase the rigidity of the base material,
Although glass cloth and adhesive sheets filled with an inorganic material are also used, the surface of the substrate is likely to be cracked during cutting, and reliability is a problem.

The present invention has been made in view of the above, and an object of the present invention is to provide a multilayer printed wiring board in which the impact at the time of cutting is mitigated and the amount of cracks is suppressed, and a manufacturing method thereof.

[0006]

A multilayer printed wiring board according to the present invention is characterized in that it has a plurality of non-through holes at a planned cutting site of an outermost insulating layer. The method for manufacturing a multilayer printed wiring board according to the present invention is characterized by including the following steps: (a) a step of forming a multilayer printed wiring board by arranging a multilayer insulating layer and a multilayer wiring conductor layer. (B) a step of performing necessary circuit processing; (c) a step of forming a plurality of non-penetrating holes in the planned cutting site of the outermost insulating layer.

Another method for manufacturing a multilayer printed wiring board according to the present invention is a method for manufacturing a multilayer printed wiring board processed into an arbitrary size required, and is characterized by including the following steps. : (A) a step of forming a multilayer printed wiring board by arranging a multilayer insulating layer and a multilayer wiring conductor layer; (b) a step of performing necessary circuit processing; (c) a plan to cut the outermost insulating layer A step of forming a plurality of non-through holes in the portion; (d) a step of removing an unnecessary portion of the planned cutting portion other than the region where the non-through hole is formed; (e) a step of cutting the planned cutting portion.

As described above, in the multilayer printed wiring board and the method for manufacturing the same according to the present invention, since a plurality of non-through holes are formed in the surface layer (outermost insulating layer) of the portion to be cut of the substrate, the The impact of is reduced and the amount of cracks is suppressed. In particular, since the formation of the non-through holes can suppress the occurrence of cracks entering in the direction perpendicular to the cutting direction, it is possible to prevent adverse effects on the substrate and provide a highly reliable printed wiring board. .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A multilayer printed wiring board according to the present invention includes a plurality of insulating layers and a plurality of wiring conductor layers arranged in different layers (levels), and the outermost insulating layer is provided at a predetermined cutting site. It has a plurality of non-through holes. Here, the planned cutting site is a site that is planned to be cut in order to be processed into a desired size, and means a so-called rib part corresponding to the frame part of the wiring board having the product size. .

As the multilayer printed wiring board according to the present invention, known materials such as generally known materials for printed wiring boards and materials for build-up wiring boards can be arbitrarily used. The structure (arrangement) of the multi-layered insulating layer and the multi-layered wiring conductor layer is not particularly limited, and any multi-layered structure can be adopted. An adhesive sheet may be used between the insulating layer and the wiring conductor layer. Circuit configurations such as an inner layer circuit and an outer layer circuit are also arbitrary.

As the resin of the insulating layer forming the outermost layer,
Epoxy resin and polyimide resin can be preferably used. Further, as the outermost layer, an adhesive sheet that does not use glass cloth, an adhesive sheet with a copper foil that does not use glass cloth, an adhesive sheet that uses a resin composition containing an inorganic filler (for example, an epoxy resin containing an inorganic filler). It is preferable to use any one selected from the group consisting of an adhesive sheet with a copper foil using a resin composition containing an inorganic filler and a prepreg sheet in which a glass cloth is impregnated with a resin composition containing an inorganic filler. You can In the present invention, by providing the non-through holes, even when the outermost insulating layer is a hard material containing an inorganic filler, the impact at the time of cutting can be mitigated and the generation of cracks can be suppressed.

This multilayer printed wiring board is expected to be cut into an arbitrary size to be actually used after completion of necessary steps such as lamination molding and circuit formation. For the rib part that is scheduled to be cut,
A plurality of non-through holes are provided. The non-through holes are formed in the outermost layers on both the front surface and the back surface, but their positions do not have to be symmetrical between the front surface and the back surface, and can be provided at arbitrary positions. The diameter of the non-through holes varies depending on the hole forming method described later, but is preferably about 20 μm or more from the viewpoint of the effect of the present invention. The upper limit of the diameter is not particularly limited as long as it is within the width of the planned cutting site. The depth of the non-penetrating holes is preferably greater than or equal to the thickness of the outermost insulating layer from the viewpoint of the effect of the present invention. Further, the number of non-through holes is not particularly limited, but a plurality of non-through hole forming regions are provided in the planned cutting site, and about 1 to 10 non-through holes are formed in each non-through hole forming region. It is preferable. After that, if necessary, in order to facilitate the cutting, it is preferable to remove unnecessary portions of the planned cutting site other than the non-through hole forming region into slits or the like by router processing or the like.

Next, a method for manufacturing a multilayer printed wiring board according to the present invention will be described with reference to the drawings. The method for manufacturing a multilayer printed wiring board according to the present invention includes the following steps: (a) a step of forming a multilayer printed wiring board by arranging a multilayer insulating layer and a multilayer wiring conductor layer; ) A step of performing necessary circuit processing; (c) A step of forming a plurality of non-penetrating holes in the planned cutting site of the outermost insulating layer.

Further, in the method for manufacturing a multilayer printed wiring board processed into a desired arbitrary size, the above (a) is used.
In addition to the steps (a) to (c), the following steps are also included: (d) a step of removing an unnecessary portion of the planned cutting site other than the region where the non-through hole is formed; (e) a planned cutting site The process of cutting.

FIG. 1 is a sectional view schematically showing one embodiment of a method for manufacturing a multilayer printed wiring board in the order of steps. First, as the step (a), a metal-clad laminate (11) provided with a pattern (12) to be an arbitrary inner layer circuit is prepared: FIG. 1 (1), both sides of the metal-clad laminate (11). The prepreg (13) and the metal foil (14) are laminated on and are integrally molded by heating and pressing: FIG. 1 (2). In the drawing, one prepreg is laminated, but the number of prepregs is not particularly limited.

Next, in the step (b), through holes (through holes for through holes: 15) are formed in the obtained laminated plate, and a plating layer (16) is formed on the whole: FIG. 1 (3). .
Then, an outer layer circuit (17) is formed on the outer layer of the laminated board of FIG.
Apply processing. After that, on both sides (outermost layer), an adhesive film with a metal foil (181) (18: outermost insulating layer)
Are laminated so that the adhesive surface is on the inside, and are integrally molded by heating and pressing: FIG. 1 (4). In addition, you may use the adhesive film which is not provided with a metal foil. Alternatively, a prepreg and a metal foil may be used.

With respect to the obtained wiring board of FIG. 1 (4), a window hole (1) for laser processing was formed in the rib portion and other areas.
9) is formed by etching, metal oxide treatment, etc .: FIG. 1 (5). The metal foil may be removed by etching the entire surface instead of providing the window hole at a predetermined portion. If an adhesive film without a metal foil is used, it is not necessary to process the window hole.

Then, in the above step (c), the outermost insulating layer (18) at the position where the window hole of the rib portion is provided,
A non-through hole (20) (IVH: interstitial via hole) for facilitating the cutting is formed by an arbitrary method: FIG. 1 (6). Also, for window holes other than the ribs,
A non-through hole for interlayer connection between the first and second layers is formed.

In order to form the non-through holes, it is preferable to use a laser machine from the viewpoint of workability. The laser machine is a CO ₂ laser machine or UV-YA.
A known laser machine used for manufacturing a printed wiring board such as a G laser can be used. As a drilling method using a laser machine, a large window method and a direct laser method can be applied. A conformal method is also possible, but it may be necessary to etch the copper foil around the holes after forming the holes. As for the laser processing method, both burst processing and cycle processing are effective. Regarding the size of the non-through holes to be processed in the surface layer, if it is too small, the processing time increases because the number of processed holes increases, and if it is too large, the processing time per hole increases. Therefore, it is inefficient, so that it is preferably about 20 to 200 μm. When considering the minimum hole diameter of the laser machine used, 50
More preferably, it is about 150 μm. The interval between the non-through holes is not particularly limited, but is preferably as small as possible. In the case of a high-density wiring board such as a package, the distance from the edge of the board to the nearest circuit is 2
It is preferably / 3 or less. That is, for example, when the distance from the end of the substrate to the circuit is 1 mm, the distance between the non-through holes is preferably about 0.6 to 0.7 mm from the viewpoint of controlling the crack entering direction.

Further, in order to form the non-through hole, it is possible to use a known drill machine used for manufacturing a printed wiring board. The size of the non-through hole when the non-through hole is formed using a drill machine is 100 to 200 μm.
The thickness is preferably m, and more preferably 100 to 150 μm.

Next, in the obtained wiring board of FIG. 1 (6), drill holes (through holes (2
1) formation), IVH (22) formation for connecting upper and lower layers, desmear (removal of smear), plating, circuit processing, etc. are arbitrarily performed, and a resist for surface protection is applied.

Then, in the step (d), the rib portion other than the region where the non-through hole (20) is formed, that is, the portion of the rib portion that has been subjected to the window processing and the laser processing is left, and the ribs of the other substrate are left. Unnecessary parts are removed in order to facilitate cutting, and a multilayer printed wiring board is manufactured: FIGS. 1 (7) and 1 (8). FIG. 1 (8) is a partially enlarged plan view of FIG. 1 (7). This is preferably performed by forming a slit or a through hole (23) by router processing or the like, and it is preferable to make a deeper cut than the non-through hole (20) even when it does not penetrate.

Finally, in the above step (e), the rib portion is cut to manufacture a multilayer printed wiring board having an arbitrary size such as a product size. As a cutting method, a known method such as a machine cutting method and a punching method can be arbitrarily adopted.

[0024]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples without departing from the technical idea of the present invention.

[Example 1] A copper-clad laminate (trade name: MCL-E-679, 340 mm x 510 mm, manufactured by Hitachi Chemical Co., Ltd.), which is a FR-4 substrate having a thickness of 0.1 mm, is provided with an internal circuit. The pattern that becomes is applied by etching (1)
(See FIG. 1 (1)). On both sides of this copper clad laminate, a prepreg with a thickness of 0.1 mm (trade name: Hitachi Chemical Co., Ltd.)
Copper foil (thickness 12 μm) was laminated via GEA-679N (manufactured by GEA-679N) and integrally molded by heating and pressing (2) (FIG. 1).
(See (2)). The obtained laminated plate was provided with through holes and plated (3) (see FIG. 1 (3)). Next, above (3)
After the circuit processing is performed on the outer layer of the laminated plate of No. 3, the adhesive film with copper foil (trade name: MCF-6000E manufactured by Hitachi Chemical Co., Ltd., resin: epoxy resin, on both sides (outermost layer))
A thickness of 80 μm and a copper foil thickness of 12 μm) were arranged so that the adhesive surface was on the inside, and integrally molded by heating and pressing (4) (see FIG. 1 (4)).

On the wiring board of the above (4), window holes for laser processing including rib portions were formed by etching (5) (see FIG. 1 (5)). A laser machine (LCO-1C21 manufactured by Hitachi Via Mechanics Co., Ltd.) was used for the rib portion of the substrate by the large window method, and the pulse width was 10 μm.
Under the conditions of S, the number of shots 3 shots, and the processing frequency 2000 Hz, IVH having a diameter of 100 μm and a depth of 80 μm
Eight (6) are formed at equal intervals in one non-through hole forming region (see FIG. 1 (6)). Since 10 units including 6 non-through hole forming regions were formed on the entire panel, the number of non-through holes was 8 × 6 × 2 = 9 in one unit.
A total of 960 pieces were formed with 6 pieces and 10 units. The substrate of (6) thus obtained was subjected to drilling, IVH formation, desmear, plating, and circuit processing in this order, and a resist was applied. While leaving the window hole and laser processed portions of the rib portion as it is, the other rib portion (unnecessary portion of the substrate) was scraped off by router processing to produce a multilayer printed wiring board (7) and (8) (Fig. 1 (7) and (8)). The ratio of the region of the rib portion where the groove was formed and the region where it was not formed (non-through hole forming region) was about 10: 1.

[Second Embodiment] (4) in the first embodiment
After the formation of the wiring board, the entire surface of the copper foil was removed by etching, and laser processing was carried out by the direct method to prepare a multilayer printed wiring board by the same method as in Example 1.

[Embodiment 3] (3) in Embodiment 1
After forming the laminated board, the adhesive sheet (trade name: ABF-70 manufactured by Ajinomoto Co., Inc., resin: epoxy resin, thickness 7)
0 μm) was placed and integrated by heating and pressurizing, a multilayer printed wiring board was produced in the same manner as in Example 1.

[Embodiment 4] (3) in Embodiment 1
After the formation of the laminated plate of No. 1, a prepreg (trade name: GEA-679N manufactured by Hitachi Chemical Co., Ltd .: thickness 0.06 mm) and a copper foil having a thickness of 12 μm were integrated on both sides by heating and pressing, A multilayer printed wiring board was produced in the same manner as in 1.

[Embodiment 5] (4) in Embodiment 1
After forming the wiring board, the multilayer printed wiring board was produced in the same manner as in Example 1 except that the surface of the copper foil was subjected to redox treatment and laser processing was performed by the direct laser method.

[Embodiment 6] The diameter of the non-through hole is 150 μm.
A multilayer printed wiring board was prepared in the same manner as in Example 1 except for the above.

[Example 7] A multilayer printed wiring board was prepared in the same manner as in Example 1 except that the number of non-through holes was set to 5 in one non-through hole forming region.

[Comparative Example 1] A multilayer printed wiring board was prepared in the same manner as in Example 1 except that neither the window processing nor the IVH formation was performed on the rib portion in (5) of Example 1 above. It was made.

[Comparative Example 2] (6) in Example 1 above
After drilling holes, IVH formation, desmear, plating, and circuit processing on the board,
A multilayer printed wiring board was produced in the same manner as in Example 1 except that grooves were formed by cutting so that unprocessed rib portions were not left.

Each of the multilayer printed wiring boards obtained in Examples 1 to 7 and Comparative Examples 1 to 2 was punched out at a substrate temperature of 25 ° C. and 60 ° C. to obtain a product size (50 mm × 120 mm). Separated. The separated product size multilayer printed wiring board is shown in Table 1.
It had the characteristics shown in. Each test method is as follows. Crack amount: Magnification 3 using a digital microscope
The amount of cracks from the edge of the substrate (the length of the longest crack among a plurality of cracks) was measured at 00 times. Electrolytic corrosion resistance: Under the conditions of 85 ° C., 85% RH, and DC 50 V, the adhesive layer having an insulation resistance value of 10 9 Ω or more for 500 hours or more was regarded as good.

[0036]

[Table 1] From Table 1, as compared with the comparative example in which the non-through hole is not provided in the rib portion, in the multilayer printed wiring board of the example in which the non-through hole is provided, the amount of crack generation is remarkably small and the electrolytic corrosion resistance is also high. It turned out to be good.

[0037]

In the multilayer printed wiring board according to the present invention,
Since non-through holes are provided in the outermost insulating layer to facilitate cutting into a wiring board of any size, surface cracks are less likely to occur during cutting, and the insulating layer is held well and insulated. It is highly reliable. Further, the method for manufacturing a multilayer printed wiring board according to the present invention can be carried out using existing equipment, and does not impose a greater burden on the environment than ever before. Therefore, the present invention makes a great contribution to the densification, thinning, high reliability, and cost reduction of a multilayer printed wiring board.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing an embodiment of a method for manufacturing a multilayer printed wiring board in the order of steps.

[Explanation of symbols]

11 Metal-clad laminate 13 prepreg 18 Outermost insulation layer 20 non-through hole

Claims (7)

[Claims] 1. A multilayer printed wiring board having a plurality of non-penetrating holes at a planned cutting site of an outermost insulating layer. 2. The multilayer printed wiring board according to claim 1, wherein the resin forming the insulating layer is an epoxy resin or a polyimide resin. 3. An adhesive sheet in which the insulating layer does not use glass cloth, an adhesive sheet with a copper foil without glass cloth, an adhesive sheet using a resin composition containing an inorganic filler,
It is any one selected from the group consisting of an adhesive sheet with a copper foil using a resin composition containing an inorganic filler and a prepreg sheet in which a glass cloth is impregnated with a resin composition containing an inorganic filler. Or the multilayer printed wiring board according to 2. 4. A method for manufacturing a multilayer printed wiring board comprising the steps of: (a) a step of arranging a multilayer insulating layer and a multilayer wiring conductor layer to form a multilayer printed wiring board; (b) necessary A step of performing circuit processing; (c) A step of forming a plurality of non-through holes in the planned cutting site of the outermost insulating layer. 5. The method for manufacturing a multilayer printed wiring board according to claim 4, wherein the step of forming the non-through holes is performed by using a laser machine or a drill machine. 6. A method for manufacturing a multilayer printed wiring board including the following steps: (a) a step of arranging a multilayer insulating layer and a multilayer wiring conductor layer to form a multilayer printed wiring board; (b) necessary Circuit processing; (c) a step of forming a plurality of non-through holes in a planned cutting site of the outermost insulating layer; (d) an unnecessary portion of the planned cutting site other than the area where the non-through holes are formed. Step of removing; (e) Step of cutting the planned cutting site. 7. The method for manufacturing a multilayer printed wiring board according to claim 6, wherein the step of forming the non-through holes is performed by using a laser machine or a drill machine.