JP2017045862A - Printed wiring board and intermediate body of printed wiring board, and manufacturing method for printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board in which no void is generated during lamination, and to provide an intermediate body of the printed wiring board, and a manufacturing method for printed wiring board.SOLUTION: In a manufacturing method for printed wiring board where conductors 3 and insulation resin layers 2 are laminated alternately and bonded, and including a step of providing a plurality of dummy patterns 4 in a non-product region 20 between a plurality of product regions 10 arranged on the same plane of a stand 1, and forming an insulation resin layer 2 by making a molten resin 2a flow on the plurality of product regions 10 via the non-product region 20, the dummy pattern 4 has a streamline shape having the maximum width part at one end and the minimum width part at the other end, and the maximum width part is located on the upstream side in the flow direction of the molten resin 2a while the minimum width part is located on the downstream side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an intermediate of a printed wiring board that does not generate resin voids during lamination and a method for manufacturing the printed wiring board.

  2. Description of the Related Art Conventionally, with the miniaturization and high performance of electronic devices, printed wiring boards have been increased in density and multilayered. A multilayer printed wiring board is known in which conductors serving as inner layer circuits and insulating resin layers (prepreg) made of an insulating material are alternately laminated. The printed wiring board having such a multilayer structure is intended to construct a complicated electronic circuit at a high density and to mount various electronic components thereon at a high density. Manufactured by.

  In recent years, with the improvement in performance of electronic devices, electrical signals are also applied at high speed and high frequency, so that electrical characteristics required for printed wiring boards are also becoming more sophisticated. Therefore, it is important to adjust the molding thickness of the printed wiring board after lamination without variation. Variations in the molding thickness can lead to defects in electrical characteristics such as non-uniform thickness and impedance mismatch. Therefore, the density (density) of conductors (patterns) on printed wiring boards is reduced, and pattern missing parts (conductors) The dummy pattern is arranged in the sparse region of the conductor so as not to make a portion without the).

  A printed wiring board is manufactured by allocating a plurality of product areas to be printed wiring boards to a large board (hereinafter referred to as a work panel) and then collectively manufacturing the printed wiring board, and then cutting a non-product area formed outside or on the gap of the product area of the board. It is mass-produced by cutting into pieces. At this time, a dummy pattern is arranged in a sparse area of the conductor such as a non-product area in order to adjust the interlayer thickness.

In this manner, for example, Patent Documents 1 and 2 show that a dummy pattern is arranged in order to adjust the molding thickness of the printed wiring board after lamination without variation.
In Patent Document 1, a conductor circuit of an insulating substrate of a printed wiring board is formed so that a molded thickness of a multilayer printed wiring board after manufacture can be easily adjusted to a desired value without performing a lamination test. It is described that a plate thickness adjusting pattern is provided on the surface.
Japanese Patent Laid-Open No. 2004-228561 also suppresses substrate warpage (layer thickness non-uniformity) due to the difference in linear expansion coefficient between a copper foil layer and an insulating layer constituting a printed wiring board in layers, and the influence of gravity. In addition, it is described that a dummy pattern which is not an original copper wiring constituting an electronic circuit is formed in a wiring layer of a multilayer printed wiring board to ensure bending rigidity against warping.

However, even if a dummy pattern for adjusting the interlayer thickness is arranged on the printed wiring board as in Patent Documents 1 and 2, due to the following factors (i) to (v), the flow of the molten resin is insufficient at the time of lamination. Resin voids (voids) are generated, resulting in variations in the molded thickness of the printed wiring board after lamination.
(I) Use a thin insulating resin layer (prepreg) (ii) The conductor is 2/3 or more thicker than the interlayer thickness of the insulating resin layer (iii) Depending on the region between the same layers, the remaining copper ratio (conductor area) (Iv) Use a resin with low fluidity (a prepreg such as a high modulus material) (v) Use a material with a low resin amount (prepreg) It was not limited.

Japanese Patent Laid-Open No. 7-273451 JP 2000-151035 A

  It is an object of the present invention to provide a printed wiring board that does not generate resin voids during lamination, an intermediate of the printed wiring board, and a method for manufacturing the printed wiring board.

The present invention has been completed in order to solve the above problems, and has the following configuration.
(1) A region of a printed wiring board arranged on the same surface and having an insulating resin layer and a conductor formed by flowing molten resin on the upper surface alternately laminated and bonded, and the conductor is sparse A printed wiring board provided with a plurality of dummy patterns provided in a region, the dummy pattern having a streamline shape having a maximum width portion at one end and a minimum width portion at the other end, and the flow of the molten resin A printed wiring board, wherein the printed wiring board is arranged such that the maximum width portion is located on the upstream side and the minimum width portion is located on the downstream side with respect to the direction.
(2) The maximum width portion is a diameter of a great circle, the minimum width portion is a diameter of a small circle, and the dummy pattern is surrounded by a large circle, a small circle, and two tangent lines connecting these circles. The printed wiring board according to (1) having an outline.
(3) The printed wiring board according to (2), wherein the tangent has an inclination angle of 10 ° to 30 ° with respect to a center line connecting the center of the great circle and the center of the small circle.
(4) The printed wiring board according to (2) or (3), wherein a ratio of a diameter of a large circle to a small circle of the dummy pattern is 1: 4 to 1: 6.
(5) The printed wiring board according to any one of (1) to (4), wherein the dummy patterns are arranged radially from the center of the printed wiring board.
(6) A plurality of product regions arranged on the same surface and having a printed wiring board formed by alternately laminating and bonding insulating resin layers and conductors formed by flowing molten resin on the upper surface, and this product region It is an intermediate body of a printed wiring board having a non-product area in between and a plurality of dummy patterns provided in the non-product area, and the dummy pattern has a maximum width portion at one end and a minimum width portion at the other end. A printed wiring board having a streamline shape, wherein the maximum width portion is located on the upstream side and the minimum width portion is located on the downstream side with respect to the flow direction of the molten resin. Intermediates.
(7) The maximum width portion is a diameter of a great circle, the minimum width portion is a diameter of a small circle, and the dummy pattern is surrounded by a large circle, a small circle, and two tangent lines connecting these circles. The intermediate body of the printed wiring board as described in (6) which has an outline.
(8) The printed wiring board intermediate according to (7), wherein the tangent has an inclination angle of 10 ° to 30 ° with respect to a center line connecting the center of the great circle and the center of the small circle.
(9) The intermediate body of the printed wiring board according to (7) or (8), wherein the ratio of the diameter of the great circle to the small circle of the dummy pattern is 1: 4 to 1: 6.
(10) The dummy pattern is arranged in the middle of the printed wiring board according to any one of (6) to (9), which is arranged radially from the center of the work panel including the plurality of product regions and the non-product regions. body.
(11) An insulating resin layer is provided by providing a plurality of dummy patterns in a non-product region between a plurality of product regions arranged on the same surface, and allowing molten resin to flow over the plurality of product regions through the non-product region. A printed wiring board in which conductors and insulating resin layers are alternately laminated and bonded, and the dummy pattern has a maximum width portion at one end and a minimum width portion at the other end. A method for manufacturing a printed wiring board having a linear shape, wherein the maximum width portion is located on the upstream side and the minimum width portion is located on the downstream side with respect to the flow direction of the molten resin .

  According to the present invention, when the printed wiring board is manufactured, the resin melted by the dummy pattern arranged in the non-product region is smoothly flowed on the product region to form the insulating resin layer. Therefore, resin voids do not occur, and variations in the molded thickness of the printed wiring board after lamination do not occur.

It is explanatory drawing which shows the manufacturing method of the printed wiring board which concerns on one Embodiment of this invention. It is explanatory drawing which shows the dummy pattern in this invention. It is explanatory drawing which shows the printed wiring board which has arrange | positioned the dummy pattern of a different shape. (A)-(d) is a schematic sectional drawing which shows the resin flow around the dummy pattern of the shape shown in FIG. 3, respectively.

A printed wiring board according to an embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, product areas 10 serving as intermediate bodies of a plurality of printed wiring boards are arranged on a table 1, and a gap that is a non-product area 20 is formed between the product areas 10. Such product areas 10 and non-product areas 20 form a large work panel 100.
A plurality of dummy patterns 4 are provided in the non-product area 20 of the work panel 100, and the insulating resin layer 2 is caused to flow through the non-product area 20 through the molten resin 2a onto the plurality of product areas 10 having the conductors 3. Is formed. The intermediate body of the printed wiring board is formed by alternately laminating and bonding the insulating resin layers 2 and the conductors 3. The intermediate body of the printed wiring board becomes a printed wiring board through a cutting process of the non-product region 20 of the work panel 100 and the like.

  The insulating resin layer 2 is formed by curing the molten resin 2a melted by hot pressing on the product region 10, and is laminated and adhered so as to embed the conductor 3 and the dummy pattern 4. Examples of the resin that forms the insulating resin layer 2 include epoxy resin, bismaleimide-triazine resin, polyimide resin, polyphenylene ether (PPE) resin, phenol resin, polytetrafluoroethylene (PTFE) resin, silicon resin, polybutadiene resin, Examples thereof include polyester resin, melamine resin, urea resin, polyphenylene sulfide (PPS) resin, polyphenylene oxide (PPO) resin, and the like. Two or more of these resins may be mixed. The resin forming the insulating resin layer 2 may include the above-described inorganic filler, organic filler made of phenol resin or methacrylic resin. The insulating resin layer 2 is formed by curing a molten insulating resin used as an adhesive during lamination. The insulating resin layer 2 may include, for example, an insulating cloth material impregnated with an insulating resin, such as glass fiber or glass non-woven fabric, and a further insulating resin layer may be laminated through the insulating cloth material. Good.

  The molding thickness of the prepreg before it is formed on the insulating resin layer 2 is preferably thin so as to reduce the size and thickness of the printed wiring board. When the thickness is 100 μm or less, more preferably 80 μm or less, the effect of the present invention is achieved. Is expensive.

The conductor 3 serves as an inner layer circuit of the printed wiring board in the product region 10 and includes, for example, conductive resin and metal plating. For ease of processing such as etching, copper plating is applied on the copper foil. Or copper foil or copper plating.
Furthermore, when the thickness of the conductor 3 is thicker than the interlayer thickness of the insulating resin layer 2, the amount of resin is relatively reduced. Therefore, it becomes difficult to fill the portion without the conductor 3 with resin, and resin voids are easily generated. However, the resin flow is improved by the present invention, and the generation of resin voids can be eliminated. The effect of the present invention is high when the thickness of the conductor 3 is ½ or more, more preferably 2/3 or more of the interlayer thickness of the insulating resin layer 2.

  After the conductors 3 and the insulating resin layers 2 are alternately laminated so as to have an arbitrary number of layers, they are bonded by heating and pressing with a hot press to form a printed wiring board. The printed wiring board can also be provided with via holes or through holes.

  A plurality of dummy patterns 4 are provided in the non-product region 20, and the insulating resin layer 2 is formed by allowing the molten resin 2 a to flow over the plurality of product regions 10 through the non-product region 20. Further, the dummy pattern 4 can be used not only in the non-product region 20 but also in a region where the conductor 3 in the product region 10 is sparse. The material of the dummy pattern 4 is preferably the same material as that of the conductor 3 serving as the inner layer circuit.

As shown in FIG. 2, the dummy pattern 4 has a large circle 42 whose maximum width portion is a diameter at one end and a small circle 41 whose minimum width portion is a diameter at the other end. A streamlined outline surrounded by two tangent lines 43 connecting the two.
The tangent line 43 has an inclination angle α of 10 to 30 ° with respect to the center line 44 connecting the center of the great circle 42 and the center of the small circle 41.
Furthermore, the ratio of the diameters of the small circle 41 and the large circle 42 of the dummy pattern 4 is preferably 1: 4 to 1: 6.
By setting the inclination angle α and the ratio of the diameters of the small circle 41 and the large circle 42 within the above range, the small pattern 41 can be arranged as a tip surface, and the contour of the dummy pattern 4 becomes more streamlined. The flow of the molten resin can be made smooth.

  The dummy pattern 4 is arranged on the same plane as the conductor 3 so that the great circle 42 is located on the upstream side and the smallest circle 41 is located on the downstream side with respect to the flow direction of the molten resin 2a. According to such a shape of the dummy pattern 4, the molten resin 2 a that has flowed over the product region 10 is not blocked, so that the interlayer thickness of the insulating resin layer 2 formed by curing the molten resin 2 a is adjusted uniformly. It is possible to prevent voids (voids) due to insufficient flow of the molten resin 2a.

Furthermore, the dummy patterns 4 are preferably arranged radially from the center of the work panel 100. When the dummy patterns 4 are arranged radially from the center, the molten resin 2a melted by hot pressing flows in the non-product region 20 from the center (upstream side) of the work panel 100 toward the downstream direction as indicated by an arrow C in FIG. Therefore, the molten resin 2a easily flows to the end of the printed wiring board. At this time, in the dummy pattern 4, the large circle 42 of the maximum width portion faces the center (upstream side) direction of the work panel 100.
Further, in the printed wiring board in the product area 10, the dummy pattern 4 can be similarly provided in the area where the conductor 3 of the printed wiring board is sparse. That is, the dummy pattern 4 has a streamline shape having a maximum width portion at one end and a minimum width portion at the other end, and the maximum width portion is upstream and the minimum width portion is in the flow direction of the molten resin 2a. Is arranged on the downstream side. Further, the dummy patterns 4 may be arranged radially from the center of the printed wiring board.
Such an arrangement of the dummy patterns 4 is effective when, for example, a resin having low fluidity (a prepreg such as a high modulus material) or a material having a low resin amount (a prepreg) is used.

Next, a method for manufacturing a printed wiring board according to the present invention will be described. The method for producing a printed wiring board according to the present invention includes the following steps (I) to (III).
(I) A step of simultaneously forming a conductor in a plurality of product regions on a flat insulating resin layer or an insulating plate and a dummy pattern in regions where conductors in the non-product region and the product region are sparse.
(II) Stack the prepreg and the conductor layer (copper foil, etc.) in this order on both sides of the insulating resin layer or insulating plate on which the conductor and dummy pattern are formed, melt the prepreg resin by hot pressing, and melt the molten resin into multiple products A step of forming an insulating resin layer by allowing it to flow over the region and then curing.
(III) A step of further forming a conductor on the insulating resin layer.

  The resin flow of the molten resin around the dummy pattern in the above-described printed wiring board manufacturing method will be described with reference to FIGS. At this time, the dummy pattern 4 described above is used, and the description of each part is omitted.

  FIG. 3 shows a printed wiring board in which a plurality of dummy patterns 5 to 7 having a conventional shape (rectangular, square, circular) and a dummy pattern 4 according to the present embodiment are arranged in the non-product area 20. At this time, the flow of the molten resin 2a flowing around each of the dummy patterns 4 to 7 is indicated by arrows in FIGS.

According to FIGS. 4A to 4D, when the molten resin 2a flows from the upstream side A to the downstream side B in the flow direction, the dummy patterns 5 to 7 having a conventional shape (rectangular, square, circular) are As shown in FIGS. 4A to 4C, the flow of the surrounding resin is blocked. For this reason, voids 9 (voids) are generated because the resin hardly flows into the tip of the dummy pattern.
On the other hand, the streamlined dummy pattern 4 according to the present invention as shown in FIG. 4 (d) has the surface of the maximum width portion (the great circle 42) on the upstream side A and the downstream side B. The surface of the minimum width part (small circle 41) is located. Therefore, since the slope is provided from the surface of the maximum width portion (large circle 42) on the upstream side A to the surface of the minimum width portion (small circle 41) at the tip, the flow of the molten resin 2a from the dummy patterns 5 to 7 occurs. The generation of voids 9 can be suppressed smoothly.

As described above, if the streamlined dummy pattern 4 is used, the molten resin 2a smoothly flows and spreads, so that it is possible to form a resin voidless and there is no variation in the molding thickness due to the resin flow. As a result, it is possible to use a thin prepreg, which has conventionally been difficult due to the occurrence of resin voids, or to use a conductor 3 having a thickness of 2/3 or more of the insulating resin layer 2, and between the same layers. Even when there is a remaining copper ratio gap (there is a difference in the area ratio of the conductor 3), the generation of resin voids can be suppressed, and a thin substrate such as a module substrate is highly effective.
Furthermore, as the resin material of the insulating resin layer 2, a resin having a low fluidity (flow property) or a resin having a low resin amount can be used.
Further, the dummy pattern 4 can be used not only in the non-product area 20 of the printed wiring board but also in an area where the conductor 3 in the product area 10 of the printed wiring board is sparse. Therefore, it is possible to stack with a margin with respect to the resin void.
The above description does not mention the type of printed wiring board except for the module substrate for the description of the plate thickness, but the present invention is not limited to a normal multilayer printed wiring board, but a build-up multilayer printed wiring board, Needless to say, the present invention can be applied to multiple multilayer printed wiring boards, bonded multilayer printed wiring boards, and the like.

1 unit 2 Insulating resin layer 2a Molten resin 3 Conductor 4 Dummy pattern 5 Dummy pattern 6 Dummy pattern 7 Dummy pattern 9 Void 10 Product area 20 Non-product area 41 Small circle 42 Large circle 43 Tangent 44 Center line 100 Work panel α Tilt angle

Claims (11)

Provided in the sparse area of the printed wiring board where the insulating resin layers and conductors, which are arranged on the same surface and made by flowing molten resin on the upper surface, are alternately laminated and bonded, and in the sparse area Printed wiring board provided with a plurality of dummy patterns,
The dummy pattern has a streamline shape having a maximum width portion at one end and a minimum width portion at the other end, and the maximum width portion is upstream and the minimum width portion is downstream with respect to the flow direction of the molten resin. A printed wiring board, wherein the printed wiring board is arranged so as to be located on a side.   The maximum width portion is a diameter of a great circle, the minimum width portion is a diameter of a small circle, and the dummy pattern has a contour surrounded by a large circle, a small circle, and two tangent lines connecting these circles. The printed wiring board according to claim 1.   The printed wiring board according to claim 2, wherein the tangent has an inclination angle of 10 ° to 30 ° with respect to a center line connecting the center of the great circle and the center of the small circle.   The printed wiring board according to claim 2 or 3, wherein a ratio of a diameter of a large circle and a small circle of the dummy pattern is 1: 4 to 1: 6.   The printed wiring board according to claim 1, wherein the dummy patterns are arranged radially from the center of the printed wiring board. A plurality of product regions arranged on the same surface and having a printed wiring board formed by alternately laminating and bonding insulating resin layers and conductors formed by flowing molten resin on the upper surface, and between these product regions An intermediate body of a printed wiring board provided with a non-product area and a plurality of dummy patterns provided in the non-product area,
The dummy pattern has a streamline shape having a maximum width portion at one end and a minimum width portion at the other end, and the maximum width portion is upstream and the minimum width portion is downstream with respect to the flow direction of the molten resin. An intermediate of a printed wiring board, wherein the printed wiring board is disposed so as to be located on the side.   The maximum width portion is a diameter of a great circle, the minimum width portion is a diameter of a small circle, and the dummy pattern has a contour surrounded by a large circle, a small circle, and two tangent lines connecting these circles. The intermediate body of the printed wiring board of Claim 6.   The intermediate body of the printed wiring board according to claim 7, wherein the tangent has an inclination angle of 10 ° to 30 ° with respect to a center line connecting the center of the great circle and the center of the small circle.   The intermediate body of the printed wiring board according to claim 7 or 8, wherein a ratio of a diameter of a large circle and a small circle of the dummy pattern is 1: 4 to 1: 6.   The intermediate body of the printed wiring board according to any one of claims 6 to 9, wherein the dummy patterns are arranged radially from the center of a work panel having the plurality of product regions and the non-product regions. A plurality of dummy patterns are provided in a non-product region between a plurality of product regions arranged on the same surface, and an insulating resin layer is formed by allowing molten resin to flow over the plurality of product regions through the non-product region. A method of manufacturing a printed wiring board including a process, wherein a conductor and an insulating resin layer are alternately laminated and bonded,
The dummy pattern has a streamline shape having a maximum width portion at one end and a minimum width portion at the other end, and the maximum width portion is upstream and the minimum width portion is downstream with respect to the flow direction of the molten resin. A printed wiring board manufacturing method, wherein the printed wiring board is arranged so as to be positioned on a side.

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