JP2008243889A - Wiring substrate and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a placing method capable of manufacturing a minute multilayer wiring substrate with high quality and with high productivity, by relaxing stress difference at thermal pressing. <P>SOLUTION: In the method of manufacturing a multilayer wiring substrate, laminates and press boards are alternately stacked to form a lamination structure, which is heated and pressurized. By adjusting placing position of a plurality of the laminates placed on the same press board, a stress difference between the laminates in the direction vertical to the stacking direction can be relaxed. So, a high agreement precision is assured between a wiring layer and an interlayer connection means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a wiring board and a wiring board manufactured by the manufacturing method.

  In recent years, with the downsizing and speeding up of electronic devices, it has become important to increase the density and reduce the thickness and weight of wiring boards on which electronic components are mounted.

  A conventional method for manufacturing a wiring board will be described below. First, the laminated body provided with the interlayer connection means and the press plate are alternately stacked, and heated and pressurized by a hot press process. The resin component contained in the laminate is melted and fluidized by a hot press process to fill the voids in the laminate, and the layers of the laminate are electrically connected by the interlayer connection means. Next, a predetermined wiring layer is formed on both surface layers of the laminate to obtain an inner layer substrate. Next, the laminated body is stacked on both surface layers of the inner layer substrate, and heated and pressurized by a hot press process. The resin component contained in the laminate is melted and fluidized by a hot pressing process to fill the gap between the laminate and the inner layer substrate and the laminate, and the interlayer connection means electrically connects the interlayer between the inner layer substrate and the laminate. Connect to. Next, a predetermined wiring layer is formed on both surface layers of the inner layer substrate to complete the multilayer wiring substrate.

  Since the wiring layers of each layer of the laminate are electrically connected by the interlayer connection means, it is important to improve the accuracy of matching between the wiring layer on the plane perpendicular to the stacking direction and the interlayer connection means to increase the density of the multilayer wiring board. It is.

  However, in the hot pressing process, the dimension of the laminate changes due to the flow / curing / shrinkage of the resin component contained in the laminate and the thermal expansion / contraction of the press plate or laminate, so the stacking direction of the interlayer connection means The position in the direction perpendicular to the direction changes, and there is a problem that it is difficult to ensure high matching accuracy between the interlayer connection means and the wiring layers of each layer of the laminate.

  There has been proposed a manufacturing method that reduces the dimensional change of the laminate by adjusting the thermal expansion coefficients of the press plate and the laminate (see, for example, Patent Document 1 and Patent Document 3).

On the other hand, the manufacturing method which arrange | positions several laminated bodies on the same press board is generally employ | adopted conventionally conventionally for productivity improvement (for example, refer patent document 1 and patent document 2).
JP 2001-326458 A JP 2003-188493 A JP 2001-177244 A

  However, in the conventional configuration, a phenomenon occurs in which the dimensional change of the laminated body arranged between the press plates is not uniform within the plane of the laminated body but varies depending on the location. The layered body changes in size almost uniformly even when it expands due to heating and shrinkage due to thermosetting reaction, but in the hot press process, high pressure is applied while sandwiched between press plates. This behavior is affected by the stress from the press plate. That is, when a laminate is disposed between press plates, each of the press plate and laminate tends to expand radially from the center to the periphery when expanded, and conversely contracts from the periphery to the center when contracted. . Therefore, when the center positions of both the press plate and the laminate do not match, a place where the directions of expansion and contraction of both overlap or cancel each other occurs, and as a result, the laminate is removed from the press plate. Under the influence of the stress, the dimensional change of the laminate is not uniform in the plane but varies depending on the location.

  An example in which two laminated bodies are placed side by side on a press plate will be described with reference to FIG. FIG. 6 is a plan view showing the position where the laminate is placed on a conventional press plate, and shows a case where two laminates 120 and 130 are placed side by side on the press plate 110. The laminates 120 and 130 have front / back distinction and up / down / left / right directions. The surface of the laminates 120 and 130 is not actually drawn at this stage, but an alphabetic character is given for convenience to indicate the direction.

  When two stacked bodies 120 and 130 are placed side by side on the press plate 110, they are generally placed in the same direction with the same surface as the upper surface as shown in FIG. This is because unnecessary reverse operation and rotation operation are not required in automatic production. In this case, the ABC portion of the left laminate 120 is a portion located on the outer side of the press plate 110, and corresponds to a place where the expansion direction of the press plate 110 and the expansion direction of the laminate 120 overlap during the heating described above. In addition, the DEF portion is a portion located on the inside of the press plate 110, and corresponds to a place where the expansion direction of the press plate 110 and the expansion direction of the laminate 120 cancel each other during the heating described above. Therefore, the ABC part of the left laminate 120 tends to be stretched during heating, and conversely, the DEF part tends to be restrained from stretching, and the ABC part and the DEF part have different dimensional change behaviors. Similarly, in the right-hand laminated body 130, the ABC part and the DEF part have different dimensional change behaviors, but the ABC part is an inward portion on the press plate 110, contrary to the left-hand laminated body 120. The DEF portion is a portion located on the outer side of the press plate 110. As a result, even in the same ABC part, the left and right laminates 120 and 130 have a difference between a portion located on the outer side of the press plate 110 and a portion located on the inner side, and the influence of the stress received from the press plate 110. , And the behavior of dimensional change is different. In this way, a wiring board having different in-plane dimensional change behaviors depending on the place on the press plate 110 is completed.

  By the way, in the production of the wiring board, the production process is moved in units of a batch of the same product, which is generally about several hundreds of the same design called a lot. In the above hot press process, several laminates 120, 130 of the same lot are placed side by side on one press plate 110, and further, the press plate 110, the laminates 120, 130, and the press plate 110 are repeated thereon. The state where about 10 to 20 sheets are stacked is placed between the hot plates of the hot press device as a stacked structure for one stage. A standard hot press can process 5 to 10 stages in one apparatus. In order to process one lot, several hot presses are usually required at one time. After the hot pressing process, a circuit is formed on the wiring layer by photolithography. In this step, usually, a circuit is formed on the wiring layer by exposing one lot of wiring boards using one exposure mask film. As described above, wiring boards having different in-plane dimensional change behaviors depending on the location of the press plate 110 in the hot press process are completed. When it is attempted to expose using the IC, it becomes extremely difficult to align with the interlayer connection means that is processed at a predetermined position inside the wiring board, which deteriorates the matching accuracy between the interlayer connection means and the wiring circuit. Had problems. As a special method, a wiring board processed from the laminated body 120 placed on the left side in FIG. 6 and a wiring board processed from the laminated body 130 placed on the right side are separated, and between each press plate, a hot plate It is also possible to combine the left side and the right side and use separate exposure mask films, or make separate proportional corrections, but these methods are very laborious in reducing productivity. It is not realistic because there is a problem of complicated hook management.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a method of manufacturing a wiring board and a wiring board that improve the matching accuracy between the interlayer connection means and the wiring circuit without reducing productivity. .

  In order to solve the above-described conventional problems, a method of manufacturing a wiring board according to the present invention includes a step of placing a laminated structure in which laminated bodies and press plates are alternately stacked in a hot press device, A heat pressing step for heating and pressurizing the laminated structure with a hot plate, and the front and back surfaces of a plurality of laminates placed on the same press plate are the same, and the plurality of laminates are in relation to the center of the press plate It is characterized by being placed so as to be point-symmetric with respect to each other. According to this configuration, the plurality of laminates placed on the same press plate are located at substantially the same distance from the center of the press plate at the corresponding positions in the plane of each laminate. The magnitude and direction of the stress received from are substantially the same. As a result, it is possible to obtain a wiring board having substantially the same dimensional change behavior in the plane from the laminated body placed anywhere on the press plate.

  The method for manufacturing a wiring board according to the present invention includes a step of placing a laminated structure in which laminated bodies and press plates are alternately stacked in a hot press apparatus, and the laminated structure by the hot plate of the hot press apparatus. A plurality of laminates mounted on the same press plate are opposite to each other, and the plurality of laminates are mutually opposite with respect to a straight line in which the press plates are axisymmetric It is mounted so as to be line symmetric. Even in this configuration, the plurality of laminated bodies placed on the same press plate are located at substantially the same distance from the center of the press plate at the corresponding positions in the plane of each laminate. The magnitude and direction of the stress received are substantially the same. As a result, a wiring board having substantially the same behavior of partial dimensional change in the plane can be obtained from the laminated body placed anywhere on the press plate.

  According to the method for manufacturing a wiring board and the wiring board of the present invention, corresponding portions in the plane of each laminate placed on the same press plate are located at substantially the same distance from the center of the press plate. The magnitude and direction of stress received from the press plate are substantially the same. Therefore, it is possible to obtain a wiring board having substantially the same dimensional change behavior in the plane from the laminated body placed at any place on the press plate. Thereby, the matching accuracy between the interlayer connection means and the wiring circuit can be improved without lowering the productivity.

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

(Embodiment 1)
FIG. 2 is a cross-sectional view showing the inner layer substrate manufacturing method according to the embodiment of the present invention in the order of steps.

  First, as shown to Fig.2 (a), the electrically insulating base material 102 with which the adhesive bond layer 101 was formed in both surfaces is prepared. As the electrically insulating substrate 102, a film-like material having excellent dimensional stability and heat resistance is used. As such a film, for example, a synthetic resin film such as a polyimide film, a polyamide film, and a fluororesin film (for example, polytetrafluoroethylene) is preferable. Moreover, you may form with materials, such as the prepreg which impregnated the epoxy resin to the organic and inorganic (for example, glass) fiber of a woven fabric or a nonwoven fabric. As the adhesive layer 101, an epoxy adhesive or an imide adhesive can be used as a thermosetting resin. The thermosetting resin is preferably in a semi-cured state in order to ensure embedding in a wiring layer described later. For example, it is preferably formed of a material such as a polyimide resin, an epoxy resin, or a polyimide resin into which an epoxy group is introduced. As an example, glass fiber was used as the electrically insulating base material 102, and an epoxy resin was used as the adhesive layer 101. The epoxy resin was dried after application and in a semi-cured state in order to ensure the wiring layer embedding property. .

  Next, as shown in FIG. 2B, a release film 103 such as polyester is laminated on both surfaces of the electrically insulating base material 102 having the adhesive layer 101 formed on both surfaces. In this example, a polyethylene terephthalate (PET) film was used as the release film 103.

  Next, as shown in FIG.2 (c), the through-hole 104 is formed by the laser in the electrically insulating base material 102 which provided the release film. In this example, a carbon dioxide laser was used.

  Next, as shown in FIG. 2D, the through-hole 104 is filled with a conductive paste 105. In the present embodiment, filling was performed by printing the conductive paste 105 directly on the release film 103 using a screen printer as a filling method. The release film 103 serves as a printing mask and prevents contamination of the adhesive layer 101 surface. The conductive paste 105 is made of at least a conductive powder and a thermosetting resin. Examples of the conductive powder include metal powders such as copper powder, silver powder, nickel powder, and aluminum powder, and powders having a coating layer of the above metal, and the form thereof is resin-like, flake-like, spherical, and amorphous. Any form may be sufficient. Thermosetting resins include known resins such as phenol resins, naphthalene resins, urea resins, amino resins, alkyd resins, silicon resins, furan resins, unsaturated polyester resins, epoxy resins, polyurethane resins, etc. Can be combined as appropriate. In addition, an additive or a solvent can be added to adjust the oxidation stability and viscosity of the conductive paste 105. In addition, examples of the method for providing the conductive paste 105 with reducing properties include addition of a reducing agent and use of an amine curing agent, but the method is not limited thereto. Examples of the reducing agent include known reducing agents such as fatty acids, but are not limited thereto.

  Next, as shown in FIG.2 (e), the said release film 103 of both surfaces is peeled from both surfaces. By forming the conductive paste 105 in a projecting shape, the absolute amount of the conductive paste 105 can be increased and the connection between the wiring layer 106 and the conductive paste 105 can be easily obtained, but this is not always necessary.

  Next, as shown in FIG. 2 (f), the wiring layer 106 is overlapped from both sides of the electrically insulating substrate 102 to obtain a laminated body. And this laminated body is mounted on a press board, and also a press structure, a laminated body, and a press board are alternately laminated | stacked one by one, and a laminated structure is comprised. Furthermore, this laminated structure is placed between hot plates of a hot press and heated and pressurized. By heating and pressurizing, the adhesive layer 101 flows and hardens, and the conductive paste 105 in the through-hole 104 is compressed, and the resin component in the conductive paste 105 flows and hardens to the adhesive layer 101 to conduct electricity. The conductor component in the paste 105 is densified, and electrical connection between the wiring layers 106 on both surfaces of the electrically insulating substrate 102 is obtained. As the press plate, a metal plate, a SUS plate, a carrier plate, a dummy plate, or the like is used. In this embodiment, SUS304H is used as the press plate, and a conductor such as metal foil is used as the wiring layer 106. In this example, copper foil was used. The thermal expansion coefficient is 16 ppm for the wiring layer (copper foil), 16 ppm for the electrically insulating substrate, and 15 ppm for the press plate (SUS304H). Preferable conditions for the hot press step are heating and pressurization using a hot press at a press temperature of 200 ° C. and a pressure of 5 to 20 MPa for 60 minutes.

  Next, as shown in FIG. 2G, a desired wiring circuit is formed by exposing and developing both surfaces of the wiring layer 106 by photolithography, thereby obtaining an inner layer substrate.

  FIG. 1 is a plan view showing the placement positions of the laminates 120 and 130 on the press plate 110 of the present invention. Considering the size of the hot press apparatus and the line width of each wiring board production line, it is standard to place two laminates 120 and 130 on one press plate 110 as shown in FIG. . Also in this embodiment, two laminates 120 and 130 each having a size of 500 mm × 330 mm were placed on the press plate 110 having a size of 770 mm × 550 mm. The laminates 120 and 130 have front / back distinction and up / down / left / right directions. At this stage, no wiring circuit is formed on the wiring layer 106 on the surface of the laminates 120 and 130, but the electrically insulating base material 102 sandwiched inside the laminates 120 and 130 is not This is because a through hole 104 is formed at a predetermined position as an interlayer connection means for electrically connecting a wiring circuit to be formed in the wiring layer 106, and the conductive paste 105 is filled therewith. In order to show this directionality, an alphabetic character is given in the drawing for the sake of convenience and explanation will be made using this.

  FIG. 1A shows a method of placing the laminates 120 and 130 on the press plate 110 in the present embodiment. As can be seen from the direction of the alphabetic characters given in the figure to clearly indicate the directionality, the two laminates 120 and 130 have the same surface of the front and back surfaces as the upper surface, and further, at the center of the press plate 110. On the other hand, they are placed so as to be in positions symmetrical with respect to each other.

  FIG. 1B shows another method of placing the laminates 120 and 130 on the press plate 110 in the present embodiment. Similarly, as can be seen from the direction of the alphabetic characters, the two laminates 120 and 130 are arranged so that the front and back surfaces are opposite to each other on the upper surface, and the press plate 110 is line-symmetric with respect to a straight line. It is placed so as to be in a position.

  In any of the above two mounting methods, the ABC portion of the left laminate 120 and the ABC portion of the right laminate 130 both correspond to being located outward on the press plate 110, and the left laminate 120 Both the DEF portion and the DEF portion of the right laminate 130 correspond to portions located on the inside of the press plate 110. Further, since the left laminate 120 and the right laminate 130 are point-symmetric with respect to the center of the press plate 110 or are symmetrical with respect to the center line, the left and right laminates 120 and 130 correspond to each other. The portion is located at substantially the same distance from the center of the press plate 110. For this reason, in the corresponding portions of the left and right laminates 120 and 130, the degree of overlap and cancellation of the expansion direction of the press plate 110 and the expansion direction of the laminate 120 during heating are substantially the same and are received from the press plate 110. The effects of stress are almost the same. As a result, it is possible to obtain a wiring board having substantially the same behavior of partial dimensional change in the plane from both the left and right laminates 120 and 130.

  When the wiring board thus heated and pressurized is used, it is possible to improve the matching accuracy between the interlayer connection means and the wiring circuit in the circuit forming process. Even if there is a part where the dimensional change is partially uneven in the plane of the wiring board, the state is almost the same for all the wiring boards, so the exposure mask film is created and corrected accordingly. This is because, if the alignment can be performed optimally, it is possible to cope with all of one lot by one exposure mask film.

  In addition, by providing direction indicating means on the laminated body, the direction of the laminated body can be easily recognized and workability can be improved. It is effective to process the direction indicating hole as the direction indicating means. As a processing method, a hole can be formed by giving a direction indication mark to the electrically insulating base material 102 with the conductive paste 105 and recognizing it with X-rays.

(Embodiment 2)
FIG. 3 is a process cross-sectional view illustrating the method of manufacturing the multilayer wiring board in the embodiment of the present invention in the order of processes.

  First, an inner layer substrate having wiring circuits on both sides is prepared. As the inner layer substrate, the substrate manufactured in Embodiment 1 may be used, or a substrate manufactured by other known methods may be used. Next, as shown in FIG. 3A, the electrically insulating base material 102 obtained through the steps up to FIG. 2E from both sides of the inner layer substrate is overlaid, and the wiring layer 106 is overlaid from both sides. A laminated body is obtained by combining them.

  Next, as shown in FIG.3 (b), it heats and pressurizes with the hot press similar to the process as described in FIG.2 (f). By heating and pressurizing, the adhesive layer 101 flows and hardens, and the conductive paste 105 in the through-hole 104 is compressed, and the resin component in the conductive paste 105 flows and hardens to the adhesive layer 101 to conduct electricity. The conductor component in the paste 105 is densified, and electrical connection between the wiring layers 106 is obtained through the interlayer connection means.

  Next, as shown in FIG. 3C, a desired wiring circuit is formed by exposing and developing both surfaces of the wiring layer 106 by photolithography, thereby completing a multilayer wiring board.

  Also in the second embodiment, as described in the first embodiment, when the stacked bodies 120 and 130 are placed on the press plate 110, the same of the front and back surfaces as shown in FIG. The upper surface is the upper surface and further placed so as to be point-symmetric with respect to the center of the press plate 110, or the upper and lower surfaces are opposite to each other as shown in FIG. Furthermore, by placing the press plate 110 so as to be in a line-symmetrical position with respect to a straight line that is line-symmetrical, the interlayer connection means of the electrically insulating substrate 102 and the outermost wiring circuit in the circuit forming process Matching accuracy can be improved.

(Embodiment 3)
FIG. 4 is a process cross-sectional view illustrating a process of forming an interlayer connection between both surface layers through the through hole of the multilayer wiring board in the embodiment of the present invention.

  First, as shown in FIG. 4A, a multilayer wiring board obtained through the steps up to FIG. 3C is prepared.

  Next, as shown in FIG.4 (b), the through-hole 107 is formed in a multilayer wiring board using a drill.

  Next, as shown in FIG. 4C, a wiring layer 108 is formed on the multilayer wiring board provided with the through holes 107 by plating.

  In the step of forming the through-hole 107, high matching accuracy between the wiring layer in the direction perpendicular to the stacking direction and the interlayer connection means can be ensured in the steps up to FIG. High matching accuracy with 107 can be ensured.

(Embodiment 4)
FIG. 5 is a process sectional view showing a process of forming a solder resist on both surface layers of the multilayer wiring board in the embodiment of the present invention.

  First, a multilayer wiring board obtained through the steps up to FIG.

  Next, as shown in FIG. 5A, solder resists 109 are formed on both surfaces of the multilayer wiring board. The solder resist can be formed by an electrostatic coating method, a screen printing method, or the like. In this embodiment, a screen printing method was used.

  Next, as shown in FIG. 5B, both sides of the solder resist 109 are exposed and developed by a photolithography method to form a solder resist having a desired shape, thereby obtaining a multilayer wiring board with solder resist.

  In the process up to FIG. 4C, high matching accuracy between the wiring layer in the direction perpendicular to the stacking direction and the interlayer connection means can be secured, so that high matching between the through-hole 107 or the wiring layer 106 and the solder resist 109 is achieved. Accuracy can be ensured.

  As described above, in the present invention, conventional facilities can basically be reused.

  In this embodiment, the example in which the wiring layer (conductive paste) is provided in advance in the electrically insulating substrate has been described. However, in the case where the wiring layer is provided in the electrically insulating substrate in the heating and pressurizing step. Has the same effect.

  In the present embodiment, a method for manufacturing an ALIVH substrate (registered trademark of Matsushita Electric Industrial Co., Ltd.), which is a conventional multilayer wiring substrate, is shown as an example, but the same applies to a method for manufacturing a general multilayer wiring substrate. Has an effect.

  Since the wiring board manufacturing method and wiring board according to the present invention can provide a fine and high-quality wiring board and the manufacturing method thereof, the manufacturing method of the multilayer wiring board and the multilayer manufactured by the manufacturing method are provided. It is useful as a wiring board.

The surface view which shows the mounting position of the laminated body on the press board of this invention Process sectional drawing which shows the manufacturing method of the inner layer board | substrate of this invention in order of a process Process sectional drawing which shows the manufacturing method of the multilayer wiring board of this invention in process order Process sectional drawing which shows the process of forming the interlayer connection between both surface layers through the through-hole of the multilayer wiring board of this invention Process sectional drawing which shows the process of forming a soldering resist on both surface layers of the multilayer wiring board of this invention Front view showing the position of the laminate on the conventional press plate

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Adhesive layer 102 Electrical insulating base material 103 Release film 104,107 Through-hole 105 Conductive paste 106,108 Wiring layer 109 Solder resist 110 Press plate 120,130 Laminate

Claims (10)

A step of placing the laminated structure in which the laminated body and the press plate are alternately stacked in a hot press device, and a hot pressing step of heating and pressurizing the laminated structure by the hot plate of the hot press device, Front and back surfaces of a plurality of laminates placed on the same press plate are the same, and the plurality of laminates are placed so as to be point-symmetric with respect to the center of the press plate A method for manufacturing a substrate. A step of placing the laminated structure in which the laminated body and the press plate are alternately stacked in a hot press device, and a hot pressing step of heating and pressurizing the laminated structure by the hot plate of the hot press device, The front and back surfaces of a plurality of laminates placed on the same press plate are opposite to each other, and the plurality of laminates are placed so that the press plates are line-symmetric with respect to a straight line. A method of manufacturing a wiring board characterized by the above. The method for manufacturing a wiring board according to claim 1, wherein the laminated body includes an electrically insulating substrate and a wiring layer disposed on both surfaces of the electrically insulating substrate. The method for manufacturing a wiring board according to claim 1, wherein the laminate includes an inner layer substrate, an electrically insulating base material disposed on at least one surface of the inner layer substrate, and a wiring layer. 5. The method for manufacturing a wiring board according to claim 3, wherein the laminate includes an interlayer connection means. After the heating and pressurization in the hot press step by the interlayer connection means, the wiring layers of the laminated body or the wiring layer of the laminated body and the wiring layer of the inner substrate are electrically connected. A method for manufacturing a wiring board according to claim 5. 6. The method of manufacturing a wiring board according to claim 5, wherein the interlayer connection means is a conductive paste filled in a through hole of the electrically insulating base material. The method for manufacturing a wiring board according to claim 1, wherein the laminated body has direction indicating means. The method of manufacturing a wiring board according to claim 1, wherein the press plate is a SUS plate. A wiring board manufactured by the manufacturing method according to any one of claims 1 to 9.

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