JP2004311926A - Multilayer printed wiring board, electronic equipment and manufacturing method and manufacturing device for multilayer printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multlayer printed wiring board, in which a miniaturization or the high density package of a part are attained and the excellent flatness of a mounting surface can be ensured, and its manufacturing method and its manufacturing device for the wiring board. <P>SOLUTION: In the multilayer printed wiring board, lands 3 as a plurality of conductor layers and wiring patterns 4 and a plurality of insulating layers 1 and 2a to 2c composed of a thermoplastic resin are laminated alternately, a plurality of the lands 3 for loading the part are formed on the surface of an insulating layer 1 as the mounting surface 1a for the part and all the wiring patterns 4 connecting these lands 3 are formed in an internal layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a multilayer printed wiring board having a conductor layer such as a component mounting land and a wiring pattern connecting the lands on the surface of an insulating layer and inside the insulating layer, an electronic device including the multilayer printed wiring board, and manufacturing of a multilayer printed wiring board. The present invention relates to a method and an apparatus for manufacturing the same. More specifically, the present invention relates to a multilayer printed wiring board, an electronic device, a method of manufacturing a multilayer printed wiring board, and a manufacturing apparatus for the same, in which lands formed on the surface of an insulating layer and wiring patterns connecting the lands are formed in different layers. .

  The multilayer printed wiring board has a wiring pattern not only on the surface on which components are mounted, but also on the inside. For example, FIG. 9 shows a plan view of the surface of a conventional multilayer printed wiring board. The lands 3 and the wiring patterns 4 are formed on the surface of the insulating layer 51 which is a mounting surface on which components are mounted.

  Further, an insulating protective film 7 (shown by hatching in the figure) is used as a solder resist for maintaining electrical insulation between the wiring patterns 4 and preventing solder from attaching to portions other than the lands 3 in a component mounting process. ) Is formed.

As a material of the insulating layer 51, a thermosetting resin is often used, and a copper foil is often used for the lands 3 and the wiring patterns 4 (for example, see Patent Document 1).
JP-A-10-322021

  In the related art, as is apparent from FIG. 9, the layout design of components on the surface has to take the wiring pattern 4 into consideration. That is, since the wiring pattern 4 exists on the surface, which is the mounting surface of the component, the degree of freedom in component arrangement is small, which hinders the reduction of the component mounting area and the high-density mounting of components. In recent years, portable information terminals typified by mobile phones, digital cameras, video cameras, and the like have been increasingly miniaturized, and accordingly, miniaturization of the printed wiring boards incorporated in these products has become indispensable. Is coming.

  In addition, the presence of the wiring pattern 4 on the surface also requires an insulating protective film 7 for protecting the wiring pattern 4 at the time of soldering or the like. The insulating protective film 7 is cured after being applied on the insulating layer 51 in a liquid state. At this time, as shown in FIG. 10, the insulating protective film 7 may be applied to a part of the land 3. In this case, the electrode portion of the component runs on the insulating protective film 7 formed on the land 3, causing poor soldering, or the component is tilted, and the other electrode portion of the component is in good contact with the corresponding land 3. It is possible that electrical contact cannot be made. In particular, this is a problem with micro components where high mounting accuracy is difficult to obtain.

  Further, the thermosetting resin is not so good in high-frequency characteristics and heat resistance, and is unable to cope with a recent increase in signal frequency and an increase in soldering temperature (reflow temperature) due to the use of lead-free solder. Furthermore, thermosetting resin substrates, such as glass epoxy, contain glass fibers and therefore have poor surface flatness, which limits the accuracy of component mounting and limits the fine patterning of the conductor layer. Also have limitations.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a multilayer printed wiring board capable of achieving miniaturization or high-density mounting of components, an electronic device including the same, a method of manufacturing a multilayer printed wiring board, and a method thereof. It is to provide a manufacturing apparatus. Another object of the present invention is to provide a multilayer printed wiring board suitable for fine patterning of a conductive layer, an electronic device provided with the same, a method for manufacturing a multilayer printed wiring board, and an apparatus for manufacturing the same.

  The multilayer printed wiring board of the present invention has a structure in which a plurality of conductor layers and a plurality of insulating layers made of a thermoplastic resin are alternately laminated, and a plurality of lands are formed on the surface of the insulating layer that is the component mounting surface. It is characterized in that the wiring patterns connecting the lands are all formed in the inner layer.

  Further, an electronic apparatus of the present invention is provided with such a multilayer printed wiring board.

  That is, there is no wiring pattern on the surface that is the component mounting surface. Therefore, it is possible to freely determine the layout of lands (including recognition marks, alignment marks, lands for heat radiation, lands for electromagnetic noise shielding and components other than for component mounting) and components without being restricted by wiring patterns on the surface. it can. In addition, the absence of a wiring pattern allows the surface area to be determined with a minimum area required for component placement. This makes it possible to reduce the surface area, that is, to reduce the planar dimensions of the multilayer printed wiring board and to mount components on the surface with high density.

  Further, the multilayer printed wiring board of the present invention has a structure in which a plurality of conductor layers and a plurality of insulating layers made of a thermoplastic resin are alternately laminated, and a plurality of lands are provided on the surface of the insulating layer which is a component mounting surface. Is formed, and among the wiring patterns connecting these lands, only those wiring patterns that can connect the lands with one straight line without obstructing the other lands are formed on the surface. It is characterized by being formed in the inner layer.

  Further, an electronic apparatus of the present invention is provided with such a multilayer printed wiring board.

  In this way, wiring by forming a wiring pattern between adjacent lands (including recognition marks, alignment marks, heat radiation lands, and electromagnetic noise shielding lands in addition to component mounting) on the inner layer. An increase in length can be prevented, and an optimum wiring layout can be performed without unnecessarily increasing the wiring length according to the arrangement relationship between lands to be electrically connected to each other. In other words, the wiring pattern is sorted between the surface and the inner layer to determine which of the wiring patterns can be shortened when the wiring pattern is formed on the surface or when the wiring pattern is formed on the inner layer.

  Further, the multilayer printed wiring board of the present invention has a structure in which a plurality of conductor layers and a plurality of insulating layers made of a thermoplastic resin are alternately laminated, and a plurality of lands are provided on the surface of the insulating layer which is a component mounting surface. In addition, a common land shared by components arranged next to each other is formed, and wiring patterns connecting these lands are all formed in an inner layer.

  Further, an electronic apparatus of the present invention is provided with such a multilayer printed wiring board.

  As described above, by sharing the land, the mounting area can be reduced, and as a result, the planar dimensions of the printed wiring board can be reduced. Alternatively, high-density mounting of components is enabled. The shape of the common land can be arbitrarily designed, for example, rectangular, L-shaped, T-shaped, cross-shaped.

  Further, the method for manufacturing a multilayer printed wiring board according to the present invention includes a step of arranging a plurality of lands on a surface of an insulating layer which is a component mounting surface, and designing all wiring patterns connecting the lands to an inner layer. A step of forming an insulating layer of a thermoplastic resin, a step of forming a land on the surface of the insulating layer based on the determined land arrangement, and a step of forming a wiring in the inner layer based on a designed wiring pattern. It is characterized by having a step of forming a pattern.

  Further, the method for manufacturing a multilayer printed wiring board according to the present invention includes a step of determining an arrangement of a plurality of lands on a surface of an insulating layer, which is a mounting surface of a component, and a step of determining a wiring pattern connecting the lands. A step of designing a wiring pattern that can connect the lands with one straight line without causing a land obstacle and a step of designing another wiring pattern as an inner layer, and a step of forming an insulating layer of a thermoplastic resin. Forming a land on the surface of the insulating layer based on the arrangement of the land, and dividing and forming the wiring pattern on the surface and the inner layer based on the designed wiring pattern. .

  The method for manufacturing a multilayer printed wiring board according to the present invention includes a step of determining an arrangement of a plurality of lands and a shared land shared by adjacent components on a surface of an insulating layer which is a component mounting surface. A step of designing all wiring patterns connecting the lands to an inner layer, a step of forming an insulating layer of a thermoplastic resin, and a step of forming a land and a shared land on the surface of the insulating layer based on the determined arrangement of the lands and the shared lands. The method is characterized by including a step of forming a land and a common land, and a step of forming a wiring pattern in an inner layer based on a designed wiring pattern.

  In addition, the apparatus for manufacturing a multilayer printed wiring board according to the present invention determines the arrangement of a plurality of lands on the surface of an insulating layer made of a thermoplastic resin, which is a component mounting surface, and all wiring patterns connecting the lands. A design device for designing the inner layer.

  Further, the apparatus for manufacturing a multilayer printed wiring board of the present invention determines the arrangement of a plurality of lands on the surface of an insulating layer made of a thermoplastic resin, which is a component mounting surface, and includes a wiring pattern for connecting the lands. Therefore, the present invention is characterized in that a design device for designing a wiring pattern that can connect the lands with one straight line without causing another land as an obstacle on the surface and a wiring pattern in the inner layer is provided.

  In addition, the apparatus for manufacturing a multilayer printed wiring board according to the present invention includes a plurality of lands, and a shared land shared between adjacent components arranged on a surface of an insulating layer made of a thermoplastic resin which is a component mounting surface. It is characterized by having a design device that determines the arrangement and designs all the wiring patterns connecting the lands in the inner layer.

  The land on the surface and the wiring pattern on the inner layer are electrically connected via through holes or vias. The wiring patterns in the inner layer are electrically connected to each other through through holes or vias. For example, the via is filled with a conductive paste or a conductor is formed by plating.

  As the interlayer connection structure using vias, a via-on-via (stack via) structure, a via-on-pad structure, a structure combining via-on-via and via-on-pad, a spiral (staggered) via structure And the like.

  The shape of the via or the through hole is not particularly limited, and examples thereof include a rectangular cross section, a trapezoidal cross section, and a barrel shape. The via diameter and the through hole diameter are determined according to the design specifications.

  Further, when the wiring pattern is removed from the surface, an insulating protective film for protecting the wiring pattern can be unnecessary. Therefore, the insulating protective film does not extend over a part of the land, and a highly reliable electrical connection between the component and the land can be secured.

  The insulating layer is formed by molding a thermoplastic resin into a desired shape. Thermoplastic resin has lower relative dielectric constant and dielectric loss tangent than thermosetting resin and has excellent high-frequency characteristics and excellent heat resistance, so printed circuit boards with high-frequency circuits and lead-free solders were used. Applicable to soldering.

  Further, there is a specific effect by using a thermoplastic resin for a multilayer printed wiring board having no wiring pattern on the surface. Since the thermoplastic resin is softened by heating, the land on the surface enters the softened thermoplastic resin by hot pressing, and the step between the land and the insulating layer is reduced. As a result, there is no object that impairs the flatness on the surface of the insulating layer, so that very excellent flatness of the mounting surface can be obtained. This leads to an improvement in mounting accuracy.

  It is preferable to use a liquid crystal polymer among thermoplastic resins. Liquid crystal polymers have the highest heat resistance among thermoplastic resins, and are also excellent in heat dissipation. For densely arranging components, an insulating layer having excellent heat resistance and heat dissipation is very effective. In addition, the liquid crystal polymer has the lowest linear expansion coefficient among thermoplastic resins, and has little dimensional change due to environment such as heating and moisture absorption, and is excellent in dimensional stability. Good flatness can be ensured because there are few surface irregularities due to thermal expansion and moisture absorption.

  Further, among liquid crystal polymers, it is preferable to use liquid crystal polyester. Liquid crystal polyesters having a rod-shaped rigid component in the main chain of the polymer have a large intermolecular force between the rigid linear components, and are well blended at the time of molding and crystallized, resulting in extremely excellent heat resistance. I have.

  If a conductor foil without roughening treatment is used as the conductor layer, it is possible to prevent the roughened portion from remaining on the insulating layer at the time of patterning, and to easily form a high-density pattern with a narrow pitch. Moreover, the conductor foil without the roughening treatment has an advantage that the skin resistance and the transmission loss are smaller than the conductor foil subjected to the roughening treatment. Further, by not performing the roughening treatment on the conductive foil, it is possible to reduce the number of steps and the number of management steps.

  In addition, performing a treatment other than the roughening treatment (eg, deposition of a special metal such as zinc, nickel, cobalt, tungsten, and molybdenum) on the surface to which the conductor foil is to be adhered improves the adhesion between the conductor foil and the insulating layer. It is also effective in preventing rust and discoloration. Alternatively, the conductor foil can be hardly peeled off by embedding the conductor foil in the insulating layer so as to be in close contact therewith. Further, a chromate treatment for the purpose of rust prevention for forming a chromate film on the surface of the conductor foil may be performed.

  In addition, a conductive foil produced by a rolling method can produce a thinner conductor foil more stably than an electrolytic method. A thin conductive foil can easily process a fine pattern, further shorten the etching time at the time of patterning, make the cross section nearly rectangular, and easily control impedance.

  The insulating layer may be made of only a thermoplastic resin, or may be mixed with a reinforcing material such as glass fiber to improve strength and elastic modulus to improve dimensional stability. Further, in addition to the structure in which the entire structure is made of a thermoplastic resin, a structure in which a thermoplastic resin is used in a core portion and glass fibers are used in a surface layer, or the reverse structure may be used.

  Examples of components to be mounted include a chip resistor, a chip capacitor, a semiconductor package component, a semiconductor bare chip, and a connector.

  Further, not only the land but also a symbol mark such as a part number may be printed on the surface. This is formed, for example, of the same material as the land in the same step as when the land is formed.

  Lands for heat radiation and electromagnetic noise shielding can be provided not only on the surface but also on the inner layer. The shape and size of the recognition mark (alignment mark) formed on the surface are arbitrary, and examples thereof include a shape such as a circle, a triangle, and a square. Lands for recognition marks, heat radiation, electromagnetic noise shielding, and the like need not be formed if unnecessary.

  According to the present invention, all of the wiring patterns connecting the lands formed on the surface of the insulating layer, which is the mounting surface of the component, are formed on the inner layer except for those that can be formed shorter on the surface, Components can be placed on the mounting surface without being restricted by wiring patterns, and components can be concentrated and placed as much as the wiring pattern has disappeared or reduced on the surface, reducing the mounting area, or And a high-density mounting can be achieved.

  Further, if the wiring pattern disappears from the surface, the insulating protective film for protecting the wiring pattern can be made unnecessary from the surface. As a result, good flatness of the surface can be ensured, and the insulating protective film does not cover the lands, thereby preventing poor joining between the components and the lands.

  Furthermore, since the insulating layer is made of a thermoplastic resin, by performing hot pressing, the land can be penetrated into the softened thermoplastic resin, thereby alleviating surface irregularities. This leads to stabilization and high precision of component mounting by suppressing the inclination and displacement of the component during mounting.

[First Embodiment]
The multilayer printed wiring board according to the present embodiment is formed by laminating, for example, four insulating layers 1, 2a to 2c formed in a sheet shape as shown in FIG. Specifically, the insulating layer 2a is superimposed on the back surface (the surface opposite to that shown) of the mounting surface 1a, which is the surface of the insulating layer 1, and the insulating layer 2b is superimposed on the back surface of the insulating layer 2a. The insulating layer 2c is overlaid on the back surface of the insulating layer 2b.

  A plurality of lands 3 for component mounting are formed on the surface of the insulating layer 1 and function as component mounting surfaces 1a. The electrode portion of the component is soldered to the land 3. Only the land 3 is formed as a conductor layer on the mounting surface 1a. Note that no insulating protective film such as a solder resist is formed, and the surface of the insulating layer 1 is directly exposed to the outside.

  The wiring pattern 4 connecting the lands 3 is formed on the insulating layers 2a to 2c. In each of the insulating layers 2a to 2c, for example, a wiring pattern 4 is formed only on one surface thereof.

  The wiring pattern 4 formed on the insulating layer 2a is an inner layer pattern sandwiched between (the back surface of) the insulating layer 1 and the insulating layer 2a, and the wiring pattern 4 formed on the insulating layer 2b is formed of the insulating layer 2a and the insulating layer 2a. 2b, and the wiring pattern 4 formed on the insulating layer 2c becomes an inner layer pattern sandwiched between the insulating layer 2b and the insulating layer 2c.

  The lands 3 and the wiring patterns 4 and the wiring patterns 4 of each layer are electrically connected by a conductive paste filled in vias as described later.

  As described above, in the present embodiment, only the lands 3 are formed on the surface on which components are mounted, and the wiring patterns 4 connecting the lands 3 are all laid out in the inner layer.

  Conventionally, like a multilayer printed wiring board 50 shown in FIG. 2, a plurality of components 5 are mounted on the surface thereof, and a wiring pattern 4 connecting between the electrode portions of these components 5 is also formed on the same surface. I was On the other hand, in the multilayer printed wiring board 20 of the present embodiment, the wiring pattern 4 disappears from the surface thereof (moves to the inner layer), and only the component 5 is provided.

  As a result, it is not necessary to secure an area for the wiring pattern 4 on the surface, and the size can be reduced by the unnecessary area. That is, the components 5 can be arranged more densely, and if the same components and the same number are used as in the related art, the multilayer printed wiring board 30 (see FIG. 2) can be made more compact. The area of the surface only needs to be at least the area necessary for component arrangement.

  This will be described with reference to FIG. 3 excluding components. The land 3 and the wiring pattern 4 are formed on the surface of the insulating layer 51 for the outer layer of the conventional multilayer printed wiring board. Further, an insulating protective film 7 (shown by hatching) such as a solder resist was formed on the surface other than the lands 3.

  On the other hand, in the present embodiment, only the lands 3 are formed on the surface of the insulating layer 1 for the outer layer. The wiring pattern 4 connecting the lands 3 is formed in an inner layer. By eliminating the wiring pattern 4 from the surface, the insulating protection film 7 for protecting the wiring pattern 4 which has been conventionally required becomes unnecessary, and the insulating protection film 7 is not formed on the surface. In the present embodiment, the insulating layer sandwiching the wiring pattern 4 transferred to the inner layer functions as a protective layer for protecting the wiring pattern 4 from an external environment.

  By arranging the lands 3 densely so as to fill a space for the unnecessary wiring patterns 4 on the surface (see the lower right in FIG. 3), the multilayer printed wiring board 11 can be reduced in size. Furthermore, the components to be mounted are changed from QFP (Quad Flat Package) in which leads are arranged around the package to BGA (Ball Grid Array) or CSP (Chip Size Package) in which electrodes such as solder bumps are arranged on the lower surface. In this case, the component arrangement area becomes smaller, so that the multilayer printed wiring board 21 on which the land 3a for the lower surface electrode is formed as shown in the lower left of FIG. As a result, the size of an electronic device including the multilayer printed wiring board 21 in the housing can be reduced.

  Alternatively, as the wiring pattern 4 is eliminated from the surface, an area where nothing is formed on the surface increases, and a new component can be arranged on that portion, and high-density mounting of components can be achieved.

  In addition, since there is no need to form an insulating protective film on the surface, the insulating protective film does not extend to a part of the land 3, and the inclination of the component and the poor solder joint at the time of mounting occur. There is no. Of course, the step of forming the insulating protective film can be omitted, so that the labor and time can be reduced.

  In addition, the degree of freedom in designing the arrangement of components on the surface is increased, which leads to a reduction in the design period. Further, in the inner layer, a wiring pattern design which does not need to consider the presence of components can be performed, and the wiring length is shortened, so that the speed of signal transmission can be increased.

[Second embodiment]
Next, a method and an apparatus for manufacturing a multilayer printed wiring board in which the wiring patterns 4 are eliminated from the surface and only the lands 3 are used as described above will be described.

  FIG. 4 is a block diagram showing a configuration of a multilayer printed wiring board manufacturing apparatus 31 according to the present embodiment. The manufacturing device 31 includes a design device 60, a plating device 44, a photolithography device 45, an etching device 46, a drilling device 47, a conductive paste filling device 48, a hot press device 49, and the like.

  The design device 60 is, specifically, a CAD (Computer Aided Design) device for efficiently performing mounting design of a multilayer printed wiring board. The mounting design is an operation of determining where to place components on the circuit diagram and how to wire between components based on the circuit diagram created by the circuit design.

  The plating apparatus 44 forms a conductor layer such as lands, wiring patterns, through holes, and vias on the insulating layer by electroplating or electroless plating. The photolithography apparatus 45 patterns the conductor layer and various resist films. The etching device 46 selectively removes the conductor layer and various resist films.

  The drilling device 47 drills via holes and through holes in the insulating layer by, for example, drilling, punching, or laser processing. The conductive paste filling device 48 fills the via with a conductive paste by, for example, a printing method. The hot press unit 49 hot-presses the foil-like conductor layer and the insulating layer and bonds them together, or hot-presses the insulating layers on which the conductor layers are formed and bonds them together.

  In manufacturing a multilayer printed wiring board, a design is first performed by the design device 60.

  In the main body of the design device 60, a keyboard 67, a CPU 68, a read-only memory (ROM) 69 storing programs executed by the CPU 68, connected to an input / output interface circuit (I / O) 66, A memory (RAM) 70 for reading and writing data is provided.

  The input / output interface circuit 66 includes a magnetic tape device 61 on which a net list (signal type, component name, component outline, component terminal number and position, connection information between terminals, etc.) is recorded. A magnetic disk device 62, a display device 63, a mouse 64, and a plotter 65 for transferring and storing necessary items from the list are connected.

  The following process is used to create a component layout diagram and a wiring pattern diagram using the design device 60.

  When the library of the net list is created in the magnetic tape device 61, the necessary net list is transferred from the magnetic tape device 61 to the magnetic disk device 62. Otherwise, the input is made directly to the magnetic disk device 62 from the keyboard 67.

  Using the netlist, the CPU 68 automatically or interactively creates a layout diagram of components arranged on the surface of the multilayer printed wiring board in accordance with a program stored in the ROM 69, and causes the display device 63 to display the layout diagram. The data is plotted on the plotter 65 and output.

  Further, the CPU 68 automatically or interactively creates a wiring pattern diagram (including a through hole connecting between layers) to be formed in the inner layer according to a program stored in the ROM 69 using the netlist, and displays the display device. 63, and plotted on a plotter 65 for output.

  When the component arrangement and the wiring pattern are designed, the multilayer printed wiring board is actually manufactured based on the design. For example, a multilayer printed wiring board having two inner wiring patterns 4 will be described with reference to FIG. The three insulating layers 41 to 43 shown in FIG. 5A are individually molded and manufactured, and then hot pressed collectively. The printed wiring board for double-sided mounting as shown in FIG. 5B is not limited to the printed wiring board for single-sided mounting, and the opposite side is formed in the same manner and the insulating layers 41, 42, 43a, and 43b are laminated. can get.

  Vias 13 are formed in the insulating layers 41, 42, 43a, 43b by, for example, a laser, and the vias 13 are filled with a conductive paste 14 by, for example, a screen printing method. Thereafter, a conductor layer is formed on one surface of each of the insulating layers 41, 42, 43a, and 43b by plating, hot pressing, transfer, or the like, and then patterning is performed.

  Alternatively, after patterning the insulating layers 41, 42, 43a, and 43b each having a conductor layer formed on one or both surfaces, the vias 13 are formed by, for example, a laser. After that, the via 13 is filled with a conductive paste 14 by, for example, a screen printing method.

  Through the above steps, the lands 3 connected to the conductive paste 14 are formed on the insulating layers 41 and 43b, and the wiring patterns 4 connected to the conductive paste 14 are formed on the insulating layers 42 and 43a. Via 13 and conductive paste 14 are not formed in insulating layer 43, and only wiring pattern 4 is formed on one surface thereof.

  Then, the respective insulating layers are stacked and hot-pressed at a temperature of, for example, about 300 ° C. to form a multilayer. Thereby, the multilayer printed wiring board shown in FIGS. 6B and 6C is obtained. Only the lands 3 are formed on the surface, and the wiring patterns 4 are formed in the inner layer. The lands 3 and the wiring patterns 4 and between the wiring patterns 4 are electrically connected by the conductive paste 14. FIG. 6A is a plan view of the land 3 portion. All lands 3 formed on the surface are electrically connected to wiring patterns 4 in the inner layer via conductive paste 14 filled in vias 13.

  The conductive paste 14 is, for example, a paste in which conductive particles such as carbon, silver, copper, gold, tin, and a mixed metal of tin and silver are mixed with a viscous binder resin at a high concentration, At the time of the above-mentioned hot pressing, it is connected to a land or a wiring pattern by contact or diffusion bonding.

  The material of the insulating layers 41 to 43 is a thermoplastic resin. As an example, a liquid crystal polymer (thermotropic liquid crystal polymer, lyotropic liquid crystal polymer), polyetheretherketone, polysulfone, polyetherimide, polyphenylether, polytetrafluoroethylene, Examples include polyethylene, polypropylene, polyester, polyimide, polyvinyl, polyarylketone, polyetherketone, polyetherketoneketone, polyphenylenesulfide, syndiotactic polystyrene, and polyethersulfone.

  The resin is not limited to a single resin, and may be a resin composite composed of a plurality of resins, or a resin obtained by adding an additive to the above resin. Examples of the additives include a heat stabilizer, an ultraviolet absorber, a light stabilizer, a coloring agent, a lubricant, a flame retardant, and an inorganic filler. This thermoplastic resin material is processed into a sheet shape of, for example, several μm to several hundred μm to obtain insulating layers 41 to 43.

  The advantages of using a thermoplastic resin will be described below.

  The relative permittivity ε = 4.2-4.8 and the dielectric loss tangent tan δ = 0.02 of the thermosetting resin, whereas ε = 3.0-3.2 and tan δ = 0.004- The value is as low as 0.005, and the dielectric loss can be reduced. In recent years, digitalization of printed wiring boards has progressed, and it has become essential to increase the speed of signals. Therefore, a printed wiring board using a thermoplastic resin having a low relative dielectric constant ε and a low dielectric loss tangent tan δ is very effective for digital equipment in which signal speed is expected to be further increased in the future.

  Further, at present, switching from leaded solder to lead-free solder is progressing, and the reflow temperature at the time of soldering increases accordingly. The thermosetting resin has a low glass transition point (120 ° C to 150 ° C), so there was no problem at the reflow temperature of conventional leaded solder, but at the reflow temperature of lead-free solder, there were fatal problems such as swelling and peeling as products. May occur. On the other hand, the thermoplastic resin has a high heat resistance temperature (glass transition point is 200 ° C. or more), and there is no problem in reflow at 260 ° C. applied to lead-free solder.

  In contrast to a thermosetting resin which burns even when heated and does not melt, the thermoplastic resin melts at a certain temperature (for example, 400 ° C.) or higher, so that it is used again as a material for printed wiring boards or other injection molded products. It becomes possible. Parts, conductors and solder can be easily separated, so that they can be reused.

  For example, the molten thermoplastic resin is solidified into pellets, and the solidified pellets are melted and molded to be reused as a material for a printed wiring board or an injection molded product. Further, by separating the solder remaining on the components and conductors separated from the substrate from the components and conductors using the difference in melting point and specific gravity, the recycling efficiency can be further improved. When eutectic solder is used as the solder, environmental pollution can be prevented by recovering the lead component.

  Further, the thermoplastic resin has less hygroscopicity than the thermosetting resin and has a long expiration date, so that inventory management is easy, and quality is not deteriorated even when exported to foreign countries (even through aircraft, ships, trucks, etc.).

  Further, the thermoplastic resin can be manufactured with a required energy amount 10 to 20% lower than that of the flame-resistant glass cloth base epoxy resin copper-clad laminate (grade FR-4), and the carbon dioxide emission can be reduced. .

  Other features include that the thermoplastic resin does not use substances that harm the global environment, and UL (Underwriters Laboratory) standards are 94V-0 and 94V-1.

  Further, there is a specific effect by using a thermoplastic resin for a multilayer printed wiring board in which the above-described surface wiring pattern is eliminated. Since the thermoplastic resin is softened by heating, the land 3 on the surface enters the softened thermoplastic resin by the above-described hot pressing step.

  That is, as shown in FIG. 7A, before the hot pressing, a step (about several tens μm) occurs between the surface of the insulating layer 41 made of the thermoplastic resin and the land 3, but after the hot pressing, As shown in FIG. 7B, the lands 3 enter the softened insulating layer 41, and the surfaces of the lands 3 become flush or the steps are reduced. Thus, the surface of the insulating layer 41 is flattened because the insulating protective film is not formed and the unevenness due to the land 3 is eliminated. Can be prevented. Since the surface of the land 3 is exposed to the outside, the electrical contact with the component electrode portion can be made well. For better soldering, the surface of the land 3 is preferably subjected to a rosin-based or water-soluble pre-flux or a metal plating such as gold plating, silver plating, tin plating or HAL (hot air leveling). .

  The components may be surface mounted or insert mounted. The electrical connection and fixation between the component and the land are performed by using leaded solder, lead-free solder, conductive adhesive, conductive paste, or the like, or wire bonding using gold or aluminum wire.

  The composition and characteristics of the solder are arbitrary. For example, in the case of a lead-free solder, tin (Sn) is 93 to 98% by weight, and the rest is composed of silver (Ag), copper (Cu) and other metals, Bismuth (Bi), zinc (Zn), cobalt (Co), nickel (Ni), indium (In), phosphorus (P), germanium (Ge) and the like can be used in a component constitution in which a trace amount is added. For example, Sn-Cu system, Sn-Ag-Cu system, Sn-Zn-Bi system, Sn-Cu-Ni system, Sn-Bi system, Sn-Zn system, Sn-Ag-Bi-Cu system, Sn-Sb System, Sn-Ag system, Sn-Cu-Sb system, Sn-Bi-Ag system, Sn-Ag-Al system, Sn-Ag-Cu-In system, Sn-Bi-Ag system, Sn-Ag-In system , Sn-Ag-Bi-In, Sn-Ag-Cu-Bi-In, Sn-Ag-Cu-Ni-Ge, Sn-Ag-Bi-Cu-Ge, Sn-Zn-Al Can be exemplified. Examples of the leaded solder include Sn-Pb-based and Sn-Pb-Ag-based solders.

  Further, since the thermoplastic resin is softened by heating and has an adhesive property, it is not necessary to provide a separate adhesive layer at the time of lamination.

  As described above, in the present embodiment, a thermoplastic resin is used as a material of an insulating layer of a multilayer printed wiring board. However, among thermoplastic resins, it is particularly preferable to use a liquid crystal polymer. The reason will be described below.

With the increasing integration of components to be mounted, conditions required for an insulating layer material of a printed wiring board are becoming stricter. Particularly required functions are heat dissipation, heat resistance, and low dielectric loss in a high frequency range. Liquid crystal polymers have the highest heat resistance among thermoplastic resins, are excellent in heat dissipation, and have low dielectric loss in a high frequency band of 10 ⁹ Hz.

  In particular, in the present embodiment, the wiring pattern is eliminated from the surface of the insulating layer, and it becomes possible to arrange components more densely. It is a great advantage that the layer has excellent heat resistance and heat dissipation.

The liquid crystal polymer has the lowest linear expansion coefficient among thermoplastic resins and is extremely small (2 × 10 ⁻⁵ ° C.- ¹ or less). In addition, there is little dimensional change due to environment such as heating and moisture absorption, and it is excellent in dimensional stability. It is thermally stable and can sufficiently withstand the use conditions of lead-free solder (for example, reflow at 260 ° C. for 10 seconds). In addition, the thermal expansion coefficient of the liquid crystal polymer is close to that of copper, which is often used as a conductor layer, so that distortion due to thermal expansion and contraction is small. There are few irregularities on the surface due to thermal expansion and moisture absorption, and in addition to the above-mentioned insulating protective film and the absence of steps due to lands, good flatness can be ensured, components can be mounted accurately, and fine patterns can be formed. It's easy to do. Further, it has characteristics of being easily formed and having high rigidity.

  In general, liquid crystal polymers are roughly classified into two types: a thermotropic liquid crystal polymer and a lyotropic liquid crystal polymer. Examples of thermotropic liquid crystal polymer include polyester, polyesteramide, polyazomethine, polyamide, polyether, polythiol, polysiloxane, polymethacrylic acid, polyacrylic acid, synthetic polypeptide, cellulose derivative, polyisocyanate, etc. Can be mentioned. Examples of the lyotropic liquid crystal polymer include a synthetic polypeptide, a cellulose derivative, an aromatic polyamide, an aromatic heterocyclic polymer, and a block copolymer.

  Among liquid crystal polymers, it is preferable to use liquid crystal polyester. Liquid crystal polyesters having a rod-shaped rigid component in the main chain of the polymer have a large intermolecular force between the rigid linear components, and are well blended at the time of molding and crystallized, resulting in extremely excellent heat resistance. I have. For example, what is called type I represented by Zyder (trade name) has the highest heat deformation temperature of 250 ° C to 350 ° C, continuous use temperature of 220 ° C to 260 ° C, and instant heat resistance of 300 ° C to 400 ° C. Up to ° C. And, even at around 300 ° C., sufficient strength is maintained. Further, dielectric loss in a high frequency band is small. For example, the relative dielectric constant (1 MHz) is 3.0 to 3.2, the dielectric loss tangent (1 MHz) is 0.015, the relative dielectric constant (1 GHz) is 3, and the dielectric loss tangent (1 GHz) is 0.003.

  Further, as an application example of the manufacturing method of the present embodiment, for example, an insulating layer on which a certain kind of wiring pattern commonly used for a multilayer printed wiring board for a specific application is formed is used as a common sheet, and lands and other wiring patterns are formed. By preparing a plurality of the insulating layers as dedicated sheets required according to various applications, it is possible to flexibly cope with products having various specifications by changing the combination of the dedicated sheets with respect to the common sheet.

  In this case, when the design is changed, it is only necessary to change only the sheet on which the layer to be changed is formed, and it is not necessary to recreate all of the layers from the beginning, so that the design period is shortened and the amortization cost is reduced. Further, the fact that the common sheet can be shared between the products reduces the amount of data to be handled and facilitates management.

  Next, a description will be given of a reliability evaluation test performed on a multilayer printed wiring board in which a wiring pattern and an insulating protective film have been removed from the surface.

  As an evaluation sample, a test substrate T-034-MIG-06 was used. The material is a liquid crystal polymer, the number of layers is 6, the total plate thickness is 0.8 mm, the conductor thickness is 18 μm, the interlayer film (insulating layer) thickness is 75 μm, and the interlayer connection is a conductive paste.

Test item: appearance.
Test conditions: The test sample after humidification under the conditions of 40 ° C., 90% Rh, and 96 hours is taken out of the constant temperature and humidity chamber, left at room temperature for 30 minutes, and passed twice through a reflow furnace having a peak temperature of 260 ° C. . Then, the surface is observed with a magnifying glass or a microscope to check for any abnormalities in appearance. The number of test samples is 5.
Judgment criteria: No abnormalities such as foreign matter, dents, scratches, dirt, and paste adhesion.
Judgment result: OK (no problem was found).

Test item: Via shape.
Test conditions: The test sample after humidification under the conditions of 40 ° C., 90% Rh, and 96 hours is taken out of the constant temperature and humidity chamber, left at room temperature for 30 minutes, and passed twice through a reflow furnace having a peak temperature of 260 ° C. . After that, it is observed with a magnifying glass or a microscope to confirm whether there is any abnormality related to the via. The number of test samples is 5.
Judgment criteria: Via shape, filling degree of conductive paste.
Judgment result: OK (no problem was found).

Test item: heat resistance.
Test conditions: The test sample after humidification under the conditions of 40 ° C., 90% Rh, and 96 hours is taken out of the constant temperature and humidity chamber, left at room temperature for 30 minutes, and passed twice through a reflow furnace having a peak temperature of 260 ° C. . Then, observe with a magnifying glass or a microscope to confirm whether there is any abnormality in appearance. The number of test samples is 5.
Judgment criteria: No blistering, peeling, measling, abnormal conductor, discoloration, etc.
Judgment result: OK (no problem was found).

Test item: Liquid phase thermal shock test Test condition: A test sample after humidification under the conditions of 40 ° C., 90% Rh, and 96 hours was taken out of a thermo-hygrostat, left at room temperature for 30 minutes, and then subjected to peak temperature. Pass twice through a reflow oven at 260 ° C. Thereafter, immersion in a liquid at 25 ° C. for 30 seconds and immersion in a liquid at 260 ° C. for 10 seconds are alternately repeated to measure the resistance change. A cycle of immersion in a liquid at 25 ° C. for 30 seconds and immersion in a liquid at 260 ° C. for 10 seconds is performed as one cycle until disconnection or up to 100 cycles. The number of test samples is 5.
Judgment criteria: Resistance change rate ΔR ≦ 30% in 20 cycles.
Judgment result: Table 1. ΔR ≦ 30% was cleared in a total of 20 cycles, and no disconnection was observed until 100 cycles. When only one sample was subjected to disconnection, no problem was observed up to 160 cycles. No disconnection occurred in any of the samples, and the resistance change rate was 0.472% on average, which was a good result.

Test item: Gas phase thermal shock test Test conditions: A test sample after humidification under the conditions of 40 ° C., 90% Rh, and 96 hours was taken out of a thermo-hygrostat, left at room temperature for 30 minutes, and then subjected to peak temperature. Pass twice through a reflow oven at 260 ° C. Thereafter, the resistance change is measured under the conditions of −40 ° C./30 minutes and 125 ° C./30 minutes. A test of 100 cycles is performed with -40 ° C / 30 minutes and 125 ° C / 30 minutes as one cycle, and the resistance change after 100 cycles with respect to the initial resistance value is confirmed. The resistance value is measured using a micro resistance measurement system, and the rate of change of the resistance value at high temperature is determined. 5 test samples.
Judgment criteria: Resistance change rate ΔR ≦ 30% in 100 cycles.
Judgment result: Table 2. The rate of change in resistance value in 100 cycles was -0.01% on average, satisfying ΔR ≦ 30%. Further, when the cycle was continued up to 500 cycles, the rate of change in resistance was 0.299 on average, satisfying ΔR ≦ 30%. No disconnection occurred in all the samples, and the resistance change rate was an average of -0.01%, which was a good result. In addition, even when the cycle was performed up to 500 cycles, no disconnection was observed in all the samples, and the resistance change rate was as good as 0.3%.

Test item: Migration Test conditions: A test sample after humidification under the conditions of 40 ° C., 90% Rh, 96 hours was taken out of the thermo-hygrostat, left at room temperature for 30 minutes, and then reflow oven at a peak temperature of 260 ° C. Through twice. In a constant temperature and humidity chamber of 85 ° C./85% Rh, a DC voltage of 50 V is applied, and the insulation resistance is measured every 6 hours, and the measurement is continuously performed for 240 hours. 5 test samples.
Judgment criteria: Insulation resistance value R ≧ 10 ⁶ Ω in wet conditions.
Judgment result: Table 3 and FIG. Line and space L / S = 100/100 μm between patterns (corresponding number I), line and space L / S = 150/150 μm between patterns (corresponding number II), 0.7 mm pitch between through holes (corresponding number III) ), Between the through-holes with a pitch of 0.8 mm (corresponding number IV), between the through-holes with a distance of 1.1 mm and the inner layer pattern (corresponding number V), and between the layers (corresponding number VI), no insulation deterioration was observed. Met.

  The insulation resistance value for each of I to VI shown in FIG. 8 is an average value of five samples performed for each of I to VI. Tables 4 to 9 show the insulation resistance values in each cycle for all samples instead of the average values. In these tables, the numbers to the right of the circled numbers (corresponding numbers above) are the sample numbers. Is shown.

  The above test items are the main test items for heat resistance when mounting components, conduction reliability for operating the product, and insulation reliability, and it was confirmed that there were no problems in all items. In the migration, the insulation resistance value is one digit higher than that of FR (flame retardant) -4 grade flame-resistant glass cloth base epoxy resin copper-clad laminate, which is a good value.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. Note that the same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

  In this embodiment, the conductor foil 35 shown in FIG. 11A is attached to the insulating layer 36 to obtain a laminate of the insulating layer and the conductor layer. The laminate shown in FIG. 11A may be used for an outer layer or an inner layer of a multilayer printed wiring board.

  The conductor foil 35 is not roughened. However, rust prevention treatment, discoloration resistance treatment, and other surface treatments may be performed as necessary. In any case, unevenness due to the roughening process is prevented from being formed on the surface of the conductive foil 35 to be bonded to the insulating layer 36.

  The conductive foil 35 has a solid shape, and after being attached to the insulating layer 36, as shown in FIG. 11B, the conductive foil 35 is patterned by wet etching. Thus, a desired circuit pattern (or land) 35a is obtained.

  Advantages of using the conductor foil 35 not subjected to such a roughening treatment will be described below in comparison with a comparative example shown in FIG.

  The conductor foil 37 shown in FIG. 12A has its attachment surface roughened by, for example, an alkaline oxidizing agent, and the roughened surface is attached to the insulating layer 36. The protruding roughened portion 37b is embedded in the insulating layer 36, thereby increasing the adhesive strength between the conductor foil 37 and the insulating layer 36.

  Although the roughening portions 37b are formed regularly at equal pitches in the drawing, in actuality, the positional relationship between the roughening portions 37b is irregular, and their sizes are not necessarily uniform.

  After the solid conductor foil 37 is attached to the insulating layer 36, as shown in FIG. 12B, the conductor foil 37 is patterned by wet etching. Thereby, a desired circuit pattern (or land) 37a is obtained.

  At this time, as shown in FIG. 12B, it is possible that a part of the roughened portion 37b into which the insulating layer 36 has entered may remain. For the recent fine patterning, the roughened portion 37b remaining on the insulating layer 36 may be a problem. That is, when the pitch between the patterns 37a is narrowed, a short circuit may occur between the patterns 37a through the roughened portions 37b remaining in the insulating layer 36.

  On the other hand, if the conductor foil 35 is not subjected to the above-described roughening treatment, the problem of short-circuit caused by the roughened portion does not occur even if the pitch between the patterns 35a becomes narrow. The surface that has not been subjected to the roughening treatment is not limited to a smooth surface without any irregularities. Even if the roughening treatment is not performed, for example, in a conductor foil obtained by the electrolytic plating method, the surface opposite to the surface in contact with the electrode surface tends to be slightly rough. It is unlikely that a short circuit will occur.

  A hot pressing method in which the conductive foil 35 and the insulating layer 36 are narrowed between hot press plates, or a roller pressing method in which the conductive foil 35 and the insulating layer 36 are pressed between a pair of rollers under heating or in a plasma atmosphere. The conductor foil 35 is attached to the insulating layer 36. Alternatively, a sputtering method or a plating method may be used.

  Since the insulating layer 36 is made of a thermoplastic resin, the adhesiveness of the insulating layer 36 is excellent due to the softening by heating, and the good adhesion between the conductive foil 35 and the insulating layer 36 can be achieved without roughening the conductive foil 35. Sex is obtained.

  For example, as shown in FIG. 16, a conductive foil having a stable thickness of 7 μm (error ± 10%) is bonded to an insulating material using a thermoplastic resin by a heating roller pressing method, and patterning is performed. When a test substrate 74 on which a pattern 75 of / space = 50 μm / 50 μm was formed was produced, it was confirmed that there was no problem such as peeling of the conductive foil and displacement during the production, and there was no problem in manufacturing the printed wiring board. In a taping test in which the tape was attached to the pattern 75 and peeled off, it was confirmed that there was no peeling or displacement.

  Further, as shown in FIG. 13, the conductive foil 35 is preferably obtained by a rolling method in which the raw material 34 is narrowed and rolled between a pair of rollers 33a and 33b. The conductor foil manufactured by the rolling method has advantages such as a smaller skin resistance and a smaller transmission loss than the conductor foil manufactured by the electrolytic plating method, and can have a thin thickness without variation.

  When the thickness of the conductor foil is large, the etching time for removing unnecessary portions during patterning becomes long, and the cross section of the pattern becomes close to a trapezoid as shown in FIG. It becomes uneven and impedes impedance control. That is, when the conductive foil 72 on the insulating layer 71 is patterned using the resist 73, the phenomenon that the etching in the lateral direction is large in the portion close to the resist 73 and the etching is small in the portion close to the insulating layer 71 is that It becomes remarkable when the thickness of 72 is large.

  By using the rolling method, it is possible to finish the conductor foil extremely thin. Therefore, the etching time can be shortened, and each pattern can be a pattern having a uniform cross-sectional shape close to a rectangle, which facilitates impedance control. In addition, the thickness of the conductor foil produced by the rolling method is extremely stable, with an error in thickness of less than about ± 10% even if the conductor foil is an extremely thin conductor foil.

  Further, as shown in FIG. 14, when the interlayer connection between the pattern 54 formed on the insulating layer 53 and the pattern 55 formed on the insulating layer 52 is performed by plating the through hole 56, In this case, the plating film 57 is formed on the pattern 55 and becomes thicker by that amount, resulting in a non-uniform trapezoidal cross-sectional shape after etching, which impedes impedance control and hinders formation of a high-definition pattern.

  On the other hand, as shown in FIG. 6B described above, if the interlayer connection is made with the conductive paste 14, the etching can be performed with the original thickness of the conductive foil, and a pattern having a cross-sectional shape close to a uniform rectangle can be obtained. be able to.

[Fourth embodiment]
If the entire wiring pattern is formed in the inner layer, there is a possibility that the wiring length between the adjacent lands A and B is unnecessarily increased as shown in FIG. That is, the land A and the land B are connected via the via a, the wiring pattern b, and the via c formed inside the insulating layer 91. In this case, the wiring length is longer than in the case where the lands A and B are connected on the surface, and the signal transmission is delayed accordingly.

  Therefore, in the present embodiment, as shown in FIG. 19, the lands 78b and 79b which are adjacent on the surface and need to be electrically connected to each other are connected by a wiring pattern 87 formed on the surface in a straight line. I am trying to be.

  That is, between the lands 78b and 79b to be electrically connected to each other, if it is possible to connect the lands 78b and 79b with a straight line without being disturbed by other lands or components on the surface, In the case where the wiring pattern length is shorter when the connection is made with the inner layer, the wiring pattern is formed in consideration of which one of the surface and the inner layer is shorter when the connection is made between the surface and the inner layer when the wiring pattern length becomes shorter. Make a distribution.

  Alternatively, as shown in FIG. 20, both lands 78b and 79b are formed as one integral common land 88, and the common land 88 is composed of a component 5a surface-mounted between the lands 78a and 78b and a land 79a, It may be shared with the component 5b surface-mounted between 79b.

  As shown in FIG. 21, the shared land may be a shared land 90 shared by the three components 5a to 5c and having a T-shape. Of course, four or more parts may be shared, and the shape may be arbitrarily set, for example, a cross shape.

  As described above, in the present embodiment, in order to reduce the planar dimension, the wiring pattern is formed as much as possible in the inner layer, and if the wiring length is increased instead of being formed in the inner layer, A wiring pattern is formed with a straight line on the surface, or lands are shared. As a result, the wiring length can be shortened and the signal transmission speed can be increased without impairing the high degree of freedom in component arrangement, the shortening of the design period, and the miniaturization of the printed wiring board.

  On the surface, in addition to the lands for mounting components, lands 77 for radiating heat and alignment marks 76 for positioning read by a camera when mounting the components, as shown in FIGS. Is formed. In addition, a land for electromagnetic noise shielding may be formed. These are formed, for example, of the same copper foil as the lands for mounting components.

  In addition, each said embodiment is not limited to an embodiment implemented independently, You may implement in embodiment which combined each embodiment.

  The multilayer printed wiring board as described above can be applied to various electronic devices such as a computer, an audio device, a video device, and a communication device.

  The number of layers of the inner wiring pattern 4 is not limited to two, but may be more or one. In addition, double-sided mounting may be used instead of single-sided mounting. The components are not limited to being mounted only on the surface, but may be incorporated inside the multilayer printed wiring board.

  Instead of stacking the layers at the end, the layers may be stacked while stacking one layer or several layers.

  When single-sided mounting is assumed, aluminum, copper, or another material having good heat dissipation properties may be bonded to the surface on which the component is not mounted to take measures for heat dissipation properties and noise.

For multi-layering, B ² it (registered trademark), which is one of the build-up methods using a conductive paste, may be used. In this method, a conical conductive paste bump is formed on a copper foil by a printing method, and the bump is made to penetrate an insulating adhesive layer and is pressed against another copper foil to form a pattern. This is repeated to form a multilayer. Furthermore, an interlayer bonding technology NMBI (Neo Manhattan Bump Interconnection) having a copper-copper metal bonding bump, an NMSS (Neo Manhattan Super Sheet), or an AGSP (Advanced Grade Solid-bump Process) technology may be used.

  Examples of the material of the conductor layer (land or wiring pattern) include Cu, Ni, Co, Au, Zn, Zn alloy, Zn-Fe, Zn-Ni, Fe, Cr, Sn, Sn alloy, Sn-Pb, Pb, and Ag. , Pt group metals, noble metal alloys, other alloys, other single metals, and the like. Alternatively, the land or the wiring pattern may be made of a conductive paste. Alternatively, the conductor layer may be formed using an additive method. The shape of the component mounting land, the land for heat radiation / electromagnetic noise shielding, the power supply / ground, the width of the wiring pattern, the thickness of the conductor layer, and the like are arbitrarily determined based on the specifications required for the printed wiring board.

  The thickness of the printed wiring board is also determined based on specifications required for the printed wiring board and electronic devices as products.

  According to the present invention, a rigid printed wiring board, a flexible printed wiring board, and as shown in FIG. 18, rigid parts 83a, 83b, 85 having hardness and strength, and flexible parts 84, 86 having flexibility are provided. Applicable to integrated flex-rigid printed wiring boards. 18A shows a flex-rigid printed wiring board in which a flexible portion 84 is integrated between two rigid portions 83a and 83b, and FIG. 18B shows a flexible portion 86 integrated so as to be cantilevered with respect to the rigid portion 85. 1 shows a finished flex-rigid printed wiring board.

  Further, the printed wiring board is not limited to a flat plate shape, and may be processed into an L shape after the component 5 is mounted as shown in FIG. The letter-shaped printed wiring board 92 may be integrated with the housing 93 as shown in FIG. Of course, it is not limited to the L-shape, and may be processed into, for example, a U-shape. Further, the printed wiring board itself may be configured as a housing of the electronic device.

  The conductor foil that has not been subjected to the roughening treatment may be applied to both the outer layer and the inner layer, or may be applied only to the outer layer or only the inner layer. It is preferable to apply a conductor foil subjected to a roughening treatment. This is because a large load is applied to the outer layer due to the mounting of components, and the outer layer is more difficult to peel off than the inner layer.

  For example, in the example shown in FIG. 17, of the four conductive layers that are interlayer-insulated by the insulating layer 80 and are connected to each other via the conductive paste 14, the inner layer 82 is made of a conductor foil that has not been subjected to a roughening treatment. For the outer layer 81, a conductor foil subjected to a roughening treatment is used. Of course, a conductor foil having all layers subjected to a roughening treatment may be used.

  For example, when soldering or repairing parts (repairing parts) by hand, there is a concern that the land formed on the surface may be peeled off or lifted up (lift-off phenomenon), see FIGS. The solder resist 7 having an opening smaller than the length and diameter of the lands A, B, and C in the planar direction is formed by positioning the openings on the lands A, B, and C. With a structure in which the lands A, B, and C are held down by the opening edges, peeling of the lands A, B, and C is suppressed.

  The thickness of the conductor foil is determined according to the required application, such as selecting a thin conductor foil if a fine pitch is required and selecting a thick conductor foil for heat dissipation effect. Is done.

  As the conductive foil, for example, a rolled foil is selected for a portion where bending is repeated, and an electrolytic foil and a rolled foil are selected according to specifications.

It is a top view for every layer of the multilayer printed wiring board of the present invention. It is the figure which compared the multilayer printed wiring board with conventional and this invention. FIG. 3 is a diagram (parts are not shown and lands are shown) comparing a multilayer printed wiring board according to the related art and the present invention as in FIG. 2. It is a block diagram showing the composition of the multilayer printed wiring board manufacturing device of the present invention. FIG. 4 is a cross-sectional view illustrating a step of laminating a multilayer printed wiring board according to the present invention. FIG. 6 is a sectional view of the multilayer printed wiring board shown in FIG. 5 after lamination and a plan view near a land. FIG. 5 is a cross-sectional view illustrating a function of a land pressed into an insulating layer by a hot press in the present invention. 5 is a graph showing a result of a migration test of a multilayer printed wiring board in the present invention. It is a top view of the component mounting surface of the conventional multilayer printed wiring board. It is sectional drawing of the principal part of the same conventional multilayer printed wiring board. FIG. 4 is a cross-sectional view of a main part of a multilayer printed wiring board using a conductor foil that has not been subjected to a roughening treatment. FIG. 3 is a cross-sectional view of a main part of a multilayer printed wiring board using a conductor foil subjected to a roughening treatment. It is a figure which shows the manufacturing process of a conductor foil by a rolling roll method. It is principal part sectional drawing of the multilayer printed wiring board connected between layers by plating. FIG. 4 is a cross-sectional view of a conductor layer in which an undercut has occurred. FIG. 4 is a plan view of a taping test substrate. It is sectional drawing of the printed wiring board comprised using the conductor foil which does not roughen the outer layer, and the conductor foil which roughened the inner layer. It is sectional drawing of a flex-rigid printed wiring board. It is a top view of a printed wired board concerning a 4th embodiment of the present invention. FIG. 14 is a plan view of a printed wiring board on which common lands are formed in a fourth embodiment. It is a top view showing the modification of a common land. FIG. 9 is a cross-sectional view for explaining an increase in wiring length when a wiring pattern connecting adjacent lands on the surface is formed in an inner layer. A rectangular opening edge portion of the solder resist is applied to a portion on the outer edge side of the rectangular land, where A is a plan view and B is a cross-sectional view. A state in which a circular opening edge of the solder resist is applied to a portion on the outer edge side of the ring-shaped land is shown, A is a plan view, and B is a cross-sectional view. FIG. 3 is a perspective view showing a printed wiring board bent in an L shape. FIG. 26 is a perspective view in which the printed wiring board of FIG. 25 is attached to a housing.

Explanation of reference numerals

  DESCRIPTION OF SYMBOLS 1 ... Insulating layer, 1a ... Mounting surface, 2a-2c ..., Insulating layer, 3, 3a ... Land, 4 ... Wiring pattern, 5 ... Parts, 7 ... Insulating protective film, 11 ... Multilayer printed wiring board, 13 ... Through Hole: 14: conductive paste, 20: multilayer printed wiring board, 21: multilayer printed wiring board, 30: multilayer printed wiring board, 31: multilayer printed wiring board manufacturing apparatus, 33a, 33b: rolling roller, 35: conductive foil (rough) 37 ... Conductor foil (with roughening treatment), 41-43 ... Insulating layer, 60 ... Design equipment.

Claims (42)

A multilayer printed wiring board in which a plurality of conductor layers and a plurality of insulating layers are alternately stacked,
The insulating layer is made of a thermoplastic resin,
A multilayer printed wiring board, wherein a plurality of lands are formed on a surface of the insulating layer which is a component mounting surface, and all wiring patterns connecting the lands are formed in an inner layer. The multilayer printed wiring board according to claim 1, wherein the thermoplastic resin is a liquid crystal polymer. The multilayer printed wiring board according to claim 2, wherein the liquid crystal polymer is a liquid crystal polyester. The multilayer printed wiring board according to claim 1, wherein an insulating protective film is not formed on the surface of the insulating layer. 2. The multilayer printed wiring board according to claim 1, wherein the land is exposed into the insulating layer with its surface exposed, and the mounting surface is flat. 3. The multilayer printed wiring board according to claim 1, wherein the conductor layer is formed of a conductor foil that has not been subjected to a roughening treatment. A multilayer printed wiring board in which a plurality of conductor layers and a plurality of insulating layers are alternately stacked,
The insulating layer is made of a thermoplastic resin,
A plurality of lands are formed on the surface of the insulating layer that is the mounting surface of the component,
Among the wiring patterns for connecting the lands, only the wiring pattern that can connect the lands with one straight line without causing another land to be an obstacle is formed on the surface, and the other wiring patterns are formed on the inner layer. A multilayer printed wiring board characterized by being formed. The multilayer printed wiring board according to claim 7, wherein the thermoplastic resin is a liquid crystal polymer. The multilayer printed wiring board according to claim 8, wherein the liquid crystal polymer is a liquid crystal polyester. The multilayer printed wiring board according to claim 7, wherein an insulating protective film is not formed on the surface of the insulating layer. The multilayer printed wiring board according to claim 7, wherein the lands expose the surface thereof and enter the insulating layer, and the mounting surface is flat. The multilayer printed wiring board according to claim 7, wherein the conductor layer is formed of a conductor foil that has not been subjected to a roughening treatment. A multilayer printed wiring board in which a plurality of conductor layers and a plurality of insulating layers are alternately stacked,
The insulating layer is made of a thermoplastic resin,
A plurality of lands are formed on the surface of the insulating layer, which is a component mounting surface, and all the wiring patterns connecting the lands are formed on an inner layer, and the surface is shared by the components arranged next to each other. A multilayer printed wiring board characterized by having a common land formed thereon. The multilayer printed wiring board according to claim 13, wherein the thermoplastic resin is a liquid crystal polymer. The multilayer printed wiring board according to claim 14, wherein the liquid crystal polymer is a liquid crystal polyester. The multilayer printed wiring board according to claim 13, wherein an insulating protective film is not formed on the surface of the insulating layer. The multilayer printed wiring board according to claim 13, wherein the land is exposed into the insulating layer with its surface exposed, and the mounting surface is flat. The multilayer printed wiring board according to claim 13, wherein the conductor layer is formed of a conductor foil that has not been subjected to a roughening treatment. An electronic device including a multilayer printed wiring board in which a plurality of conductor layers and a plurality of insulating layers are alternately stacked,
The insulating layer is made of a thermoplastic resin,
An electronic device, wherein a plurality of lands are formed on a surface of the insulating layer which is a component mounting surface, and all wiring patterns connecting the lands are formed on an inner layer. An electronic device including a multilayer printed wiring board in which a plurality of conductor layers and a plurality of insulating layers are alternately stacked,
The insulating layer is made of a thermoplastic resin,
A plurality of lands are formed on the surface of the insulating layer that is the mounting surface of the component,
Among the wiring patterns for connecting the lands, only the wiring pattern that can connect the lands with one straight line without causing another land to be an obstacle is formed on the surface, and the other wiring patterns are formed on the inner layer. An electronic device characterized by being formed. An electronic device including a multilayer printed wiring board in which a plurality of conductor layers and a plurality of insulating layers are alternately stacked,
The insulating layer is made of a thermoplastic resin,
A plurality of lands are formed on the surface of the insulating layer, which is a component mounting surface, and all the wiring patterns connecting the lands are formed on an inner layer, and the surface is shared by the components arranged next to each other. An electronic device having a shared land formed therein. A method for manufacturing a multilayer printed wiring board in which a plurality of conductor layers and a plurality of insulating layers are alternately laminated,
Determining the arrangement of a plurality of lands on the surface of the insulating layer that is the mounting surface of the component,
A step of designing all wiring patterns connecting the lands to an inner layer,
Forming the insulating layer with a thermoplastic resin;
Forming the land on the surface of the insulating layer based on the arrangement;
Forming a wiring pattern on the inner layer based on the design. A method of manufacturing a multilayer printed wiring board. The method for manufacturing a multilayer printed wiring board according to claim 22, wherein an insulating protective film is not formed on the surface of the insulating layer. 23. The multilayer printed wiring board according to claim 22, wherein the insulating layer on which the lands are formed and the insulating layer on which the wiring pattern is formed are separately manufactured, and then stacked and laminated by hot pressing. Manufacturing method. A step of preparing the conductor layer with a conductor foil that has not been subjected to a roughening treatment,
The method for manufacturing a multilayer printed wiring board according to claim 22, further comprising a step of attaching the conductive foil to the insulating layer. A step of preparing the conductor layer with a conductor foil that has been rolled by a rolling roll and has not been subjected to a roughening process;
The method for manufacturing a multilayer printed wiring board according to claim 22, further comprising a step of attaching the conductive foil to the insulating layer. A method for manufacturing a multilayer printed wiring board in which a plurality of conductor layers and a plurality of insulating layers are alternately laminated,
Determining the arrangement of a plurality of lands on the surface of the insulating layer that is the mounting surface of the component,
Among the wiring patterns that connect the lands, a wiring pattern that can connect the lands with one straight line without causing another land to interfere with the lands is designed on the surface, and another wiring pattern is designed on the inner layer. Process and
Forming the insulating layer with a thermoplastic resin;
Forming the land on the surface of the insulating layer based on the arrangement;
A method for manufacturing a multilayer printed wiring board, comprising: forming the wiring pattern on the surface and the inner layer separately based on the design. The method for manufacturing a multilayer printed wiring board according to claim 27, wherein an insulating protective film is not formed on the surface of the insulating layer. 28. After individually manufacturing the insulating layer on which the lands are formed and the insulating layer on which the wiring pattern is formed as the inner layer, these layers are stacked and stacked by hot pressing. A method for producing the multilayer printed wiring board according to the above. A step of preparing the conductor layer with a conductor foil that has not been subjected to a roughening treatment,
The method for manufacturing a multilayer printed wiring board according to claim 27, further comprising a step of attaching the conductive foil to the insulating layer. A step of preparing the conductor layer with a conductor foil that has been rolled by a rolling roll and has not been subjected to a roughening process;
The method for manufacturing a multilayer printed wiring board according to claim 27, further comprising a step of attaching the conductive foil to the insulating layer. A method for manufacturing a multilayer printed wiring board in which a plurality of conductor layers and a plurality of insulating layers are alternately laminated,
On the surface of the insulating layer, which is a component mounting surface, a plurality of lands, and determining the arrangement of shared lands shared between the components arranged next to,
A step of designing all wiring patterns connecting the lands to an inner layer,
Forming the insulating layer with a thermoplastic resin;
Forming the land and the shared land on the surface of the insulating layer based on the arrangement;
Forming a wiring pattern on the inner layer based on the design. A method of manufacturing a multilayer printed wiring board. The method for manufacturing a multilayer printed wiring board according to claim 32, wherein an insulating protective film is not formed on the surface of the insulating layer. The insulating layer on which the land and the shared land are formed, and the insulating layer on which the wiring pattern is formed are separately manufactured, and then stacked by hot pressing. A method for manufacturing a multilayer printed wiring board. A step of preparing the conductor layer with a conductor foil that has not been subjected to a roughening treatment,
The method for manufacturing a multilayer printed wiring board according to claim 32, further comprising a step of attaching the conductor foil to the insulating layer. A step of preparing the conductor layer with a conductor foil that has been rolled by a rolling roll and has not been subjected to a roughening process;
The method for manufacturing a multilayer printed wiring board according to claim 32, further comprising a step of attaching the conductor foil to the insulating layer. A plurality of conductor layers, a plurality of insulating layers made of a thermoplastic resin is a multilayer printed wiring board manufacturing apparatus that is alternately laminated,
A multi-layer printing apparatus comprising: a design device for determining an arrangement of a plurality of lands on a surface of the insulating layer which is a component mounting surface, and designing all wiring patterns connecting the lands to an inner layer. Wiring board manufacturing equipment. 38. The apparatus for manufacturing a multilayer printed wiring board according to claim 37, further comprising: a hot press device that overlaps and hot-presses the insulating layer on which the land is formed and the insulating layer on which the wiring pattern is formed. A plurality of conductor layers, a plurality of insulating layers made of a thermoplastic resin is a multilayer printed wiring board manufacturing apparatus that is alternately laminated,
The arrangement of a plurality of lands is determined on the surface of the insulating layer, which is the mounting surface of the component, and among the wiring patterns connecting the lands, the other lands are formed with one straight line without obstruction. An apparatus for manufacturing a multilayer printed wiring board, comprising: a designing device for designing a wiring pattern capable of connecting between them on the surface and another wiring pattern as an inner layer. The multilayer print according to claim 39, further comprising: a hot press device configured to hot-press the insulating layer on which the lands are formed and the insulating layer on which the wiring pattern is formed to be disposed on the inner layer. Wiring board manufacturing equipment. A plurality of conductor layers, a plurality of insulating layers made of a thermoplastic resin is a multilayer printed wiring board manufacturing apparatus that is alternately laminated,
On the surface of the insulating layer, which is a component mounting surface, determine the arrangement of a plurality of lands and a shared land shared between the adjacent components, and all wiring patterns connecting the lands. An apparatus for manufacturing a multilayer printed wiring board, comprising a design apparatus for designing an inner layer. 42. The multilayer printed wiring board according to claim 41, further comprising: a hot press device configured to overlap and heat press the insulating layer on which the lands and the shared land are formed and the insulating layer on which the wiring pattern is formed. Manufacturing equipment.

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