JP2007088058A - Multilayer substrate and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer substrate assuring that an electrode unit for mounting components is not easily peeled from a resin base material, and also to provide a method of manufacturing the same. <P>SOLUTION: The multilayer substrate 100 is formed of a laminated layer 26 in which an insulating resin base material 10 and a wiring layer 24 formed of a wiring pattern 20 are laminated alternately. On this multilayer substrate 100, an electrode unit 22 is formed wherein the electrode of the mounting component 30 is connected to a part of the wiring pattern 20 of an internal layer 10b in the laminated layer 26. This electrode unit 22 is exposed via an aperture 12 provided to the resin base material of the front surface layer 10a of the laminated layer 26, and the wiring pattern 20 forming the electrode unit 22 is held under close contact condition with just above and under resin base materials 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multilayer substrate and a manufacturing method thereof.

  Patent Document 1 discloses a multilayer substrate made of a laminate in which a thermoplastic resin base material and a wiring layer made of a wiring pattern are laminated.

For example, as shown in FIG. 6A, the multilayer substrate 103 disclosed in Patent Document 1 includes an electrode portion to which the wiring pattern 20 a and the electrode 31 of the mounting component 30 formed on a part of the wiring pattern 20 a are connected. The wiring layer 24a made of 22a is formed on the surface layer 10a of the resin base material.
Japanese Patent Application Laid-Open No. 2004-253569

  By the way, when the mounting component 30 is mounted or when the mounting component 30 is removed by repair or the like, if the electrode portion 22a is heated too much, the resin base material 10 is weakened by this heat. Then, the adhesion strength between the electrode part 22a and the resin base material 10 is lowered, and the electrode part 22a and the wiring pattern 20a may be peeled off from the surface layer 10a of the resin base material as shown in FIG. The multilayer substrate from which the electrode portion 22a and the wiring pattern 20a are peeled off from the resin base material cannot be used.

  Therefore, the present invention has been made in view of the problems as described above, and an object of the present invention is to provide a multilayer substrate in which an electrode portion to which an electrode of a mounting component is connected is difficult to peel off from a resin base material and a method for manufacturing the same. It is to provide.

  In order to solve the above-mentioned problems, the inventions according to claims 1 to 4 relate to a multilayer substrate comprising a laminate in which insulating resin base materials and wiring layers comprising wiring patterns are alternately laminated. .

  The invention according to claim 1 is a multilayer substrate composed of a laminated body in which insulating resin base materials and wiring layers made of wiring patterns are alternately laminated, and a part of an inner layer wiring pattern in the laminated body. An electrode part to which an electrode of the mounting component is connected is formed, and this electrode part is exposed through an opening provided in the resin base material of the surface layer in the laminate.

  According to the first aspect of the present invention, the electrode portion to which the wiring pattern and the electrode of the mounting component are connected is formed not on the surface layer of the substrate but on the inner layer of the multilayer substrate as in a general multilayer substrate. Moreover, the electrode part is exposed through the opening part provided in the resin base material. Thereby, since the resin base material layers immediately above and below the electrode part are in close contact with each other so as to sandwich the wiring pattern in which the electrode part is formed in part, it is possible to obtain a multilayer substrate in which the electrode part is not easily peeled off.

  The invention according to claim 2 is characterized in that the size of the electrode portion is larger than the size of the opening. According to the second aspect of the present invention, a part of the electrode portion is exposed through the opening. Moreover, the wiring pattern in which the electrode part is formed is not exposed. Therefore, the resin base material layers directly above and below the electrode part are in close contact with each other so as to sandwich the unexposed part of the electrode part and the wiring pattern. Thereby, it will be pinched | interposed into the resin base material layer right above and right below, and the peeling strength of an electrode part will increase.

  The invention according to claim 3 is characterized in that the resin substrate is formed of a thermoplastic resin film. Thereby, the multilayer substrate can be multi-layered and light-weighted. Furthermore, the multilayer structure improves the rigidity of the multilayer substrate.

  The invention according to claim 4 is characterized in that the wiring pattern is formed on one side of the resin base material. The wiring pattern of the multilayer substrate is different for each layer, and it is necessary to form the wiring pattern in advance before alternately laminating the resin base material and the wiring layer. Therefore, according to the invention described in claim 4, since the wiring pattern is formed only on one surface of the resin base material, the wiring pattern is compared with the multilayer substrate in which the wiring pattern is formed on both surfaces of the resin base material. The forming operation is simplified.

  Next, the invention described in claim 5 and claim 6 relates to a method for manufacturing a multilayer substrate.

  A manufacturing method of a multilayer substrate according to claim 5 is a stacking step of alternately stacking an insulating resin base material and a wiring layer made of a wiring pattern in which an electrode portion is formed in part to form a stacked body; It includes a thermocompression bonding process for thermocompression bonding the laminated body in the laminating direction, and an exposing process for removing a predetermined portion of the surface layer in the laminated body to expose an inner layer electrode portion in the laminated body.

  According to the invention described in claim 5, in addition to the effect of the invention described in claim 1, a number of multilayer substrates can be collectively formed by one-time thermocompression bonding to the laminate.

  The multilayer substrate manufacturing method according to a sixth aspect is characterized in that, in the exposing step, the resin base material is irradiated with laser light to provide an opening, and the electrode is exposed through the opening.

  By adopting this manufacturing method, an opening having a required size can be provided at an accurate position on the multilayer substrate. Therefore, the electrode portion can be exposed through this opening.

  Hereinafter, the best mode for carrying out the present invention will be described.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1A is a schematic cross-sectional view showing a cross-sectional structure of the multilayer substrate 100 in the present embodiment, and FIGS. 1B and 1C are perspective views from above the multilayer substrate 100. 4 and 5 are diagrams showing an outline of a manufacturing process in the method for manufacturing the multilayer substrate 100 in the present embodiment.

  As shown in FIG. 1A, the multilayer substrate 100 according to this embodiment includes a wiring layer 24 (24b to 24d) including an insulating resin base material 10 (10a to 10d) and a wiring pattern 20 (20b to 20d). Are made of the laminated body 26 alternately laminated.

  Although the constituent material and thickness of the insulating resin base material 10 are not particularly limited, the multilayer substrate 100 in the present embodiment has a thickness of about 50 as the insulating resin base material 10 made of a liquid crystal polymer (LCP). A micrometer thermoplastic resin film is used. A via hole 14 is formed in the insulating resin base material 10. Note that the rigidity of the multilayer substrate 100 is improved by alternately laminating the resin base material 10 and the wiring layer 24. Therefore, in FIG. 1, it is not necessary to form the via holes 14 so as to be shifted from side to side. For example, the via holes formed in the resin base material second layer 10b and the via holes formed in the resin base material third layer 10c are the same. Even in the position, the reliability of the multilayer substrate 100 does not deteriorate.

  The via hole 14 is filled with an interlayer connection material 16 to electrically connect the wiring pattern 20. As the interlayer connection material 16, for example, a conductive paste obtained by adding an organic solvent to metal particles such as copper, silver, and tin and kneading the organic solvent is used.

  The wiring pattern 20 is a conductor foil, for example, a low-resistance metal selected from one type selected from gold, silver, copper, aluminum, nickel, tin, or a low-resistance metal alloy selected from two or more types. It can be used and has a thickness of about 5 to several tens of micrometers. The multilayer substrate 100 in this embodiment uses a copper foil having a thickness of about 10 micrometers as the wiring pattern 20. The wiring pattern 20 constitutes a wiring layer 24 disposed between the layers of the insulating resin base material 10.

  Here, in the multilayer substrate 100 according to the present embodiment, as shown in FIG. 1A, electrodes of mounting components are connected to a part of the inner layer wiring pattern 20b (between the surface layer 10a and the second layer 10b). An electrode portion 22b is formed. Moreover, the opening part 12 which makes the electrode part 22b the bottom is provided in the resin base material of the surface layer 10a immediately above the electrode part 22b, and the electrode part 22b is exposed through the opening part 12. Thus, since the electrode part 22b is exposed through the opening part 12, a mounting component can be mounted in the electrode part 22b from the surface layer 10a side.

  Further, as shown in FIG. 1B, the size of the electrode portion 22 b is formed to be larger than the size of the opening portion 12. That is, only a part of the electrode part 22b is exposed through the opening 12, and the end part of the electrode part 22b and the end part of the wiring pattern 20b (resin base) shown by the broken line in FIG. The boundary portion with the material is not exposed through the opening 12. In addition, as shown in FIG.1 (c), the opening part 12 can be provided so that a part of wiring pattern 20b may be exposed, and it can also be set as the electrode part 22b. Also in this case, the end portion of the wiring pattern 20 b (the boundary portion with the resin base material) is not exposed through the opening 12.

  By the way, the multilayer substrate 100 in this embodiment is formed by performing thermocompression bonding on the stacked body 26 in the stacking direction of the stacked body 26 by a manufacturing method described later. Through this thermocompression bonding step, the surface layer 10a and the second layer 10b are brought into close contact with each other so as to sandwich the electrode portion 22b and the wiring pattern 20b. Then, the peeling strength of the electrode portion 22b and the wiring pattern 20b sandwiched between the surface layer 10a and the second layer 10b is higher than the peeling strength of the electrode portion 22a shown in FIG. It becomes harder to peel than 22a.

  Therefore, when mounting the mounting part on the electrode part 22b or removing the mounting part by repair or the like, even if the electrode part 22b is overheated, the electrode part 22b is not easily peeled off from the resin base material. Obtainable.

  As shown in FIG. 1, the multilayer substrate 100 according to the present embodiment includes a wiring layer 24 (24b to 24d) including four layers of resin substrates 10 (10a to 10d) and three layers of wiring patterns 20 (20b to 20d). However, it is needless to say that the number of layers is not limited to this example.

  For example, a multilayer substrate in which 50 or more layers of the resin base material 10 are laminated may be used. In addition, even if 50 layers are laminated | stacked by using a liquid crystal polymer film as the resin base material 10, the multilayer substrate 100 by which the thickness was restrained to about 2-3 millimeters or less can be obtained. This thickness is almost the same as that of a general printed circuit board in which several layers of the conventional FR-4 are laminated. Therefore, by using a liquid crystal polymer film for the resin base material 10, it is possible to obtain the multilayer substrate 100 having lightness and thinness. Furthermore, by using a liquid crystal polymer film for the resin base material 10, it is possible to obtain the multilayer substrate 100 having a low relative dielectric constant and excellent high frequency characteristics.

  Furthermore, since such a multilayer structure improves the rigidity of the multilayer substrate 100, it is possible to suppress the occurrence of warping and distortion of the multilayer substrate 100 due to changes in the surrounding environment such as temperature and humidity. Suppression of warpage and distortion of the multilayer substrate 100 leads to prevention of peeling of the wiring pattern and electrode portions formed on a part thereof.

  Next, a method for manufacturing the multilayer substrate 100 will be described with reference to FIGS. 4 (a) to 4 (e) and FIGS. 5 (a) to 5 (c). FIG. 4 is a diagram showing a process of forming the wiring layer 24 composed of the wiring pattern 20 on the insulating resin substrate 10, and FIG. 4A is a process of attaching the conductive foil 21 to the resin base material 10. (C) is a step of forming a via hole 14 by laser, (d) is a step of filling the via hole 14 with the interlayer connection material 16, and (e) is a step of attaching the protective film 18 and etching the conductive foil 21. The process of removing the protective film 18 is shown.

  FIG. 5 is a diagram showing a step of forming a multilayer substrate by laminating the resin substrate 10 on which the wiring layer 24 is formed, which is obtained through each step shown in FIG. Is a lamination process, (b) is a thermocompression bonding and cooling process, and (c) is a process of forming the opening 12 in the surface layer 10a.

  First, a process of forming the wiring layer 24 composed of the wiring pattern 20 on the insulating resin substrate 10 will be described.

  Conductive foil 21 is attached to one surface of thermoplastic insulating resin base material 10 by hot pressing or the like (FIG. 4A). In addition, as the resin base material 10, a liquid crystal polymer film can be used, for example. For example, a copper foil can be used as the conductor foil 21.

  Next, a protective film 18 for protecting the resin base material 10 is attached to a surface different from the surface on which the conductor foil 21 of the resin base material 10 is attached. And the desired wiring pattern 20 is formed by performing the etching process with respect to the conductor foil 21 (FIG.4 (b)). Note that the wiring pattern 20 may be different for each wiring layer 24 as necessary. The wiring pattern 20 is not limited to the etching process for the conductor foil, but can be formed by a pattern printing method or an ink jet method.

  After the wiring pattern 20 is formed, the via hole 14 is formed at a predetermined position of the resin base material 10 by, for example, laser processing (FIG. 4C). The via hole 14 can also be formed by a mechanical method such as drilling. Then, the via hole 14 is filled with a conductive paste 16 for interlayer connection (FIG. 4D), and the protective film 18 is peeled off (FIG. 4E).

  Subsequently, the stacking step shown in FIG. In the laminating step, the resin base material (surface layer) 10a on which the wiring layer 24 is not formed and the resin base material (inner layer) on which the wiring layer 24 is formed, for example, three layers of the second layer 10b to the fourth layer 10d are laminated. Thus, the laminated body 26 is formed.

  The laminated body 26 thus formed is subsequently subjected to a thermocompression bonding process and a cooling process. That is, the laminated body 26 is disposed in a heat press machine (not shown) in which a heater is embedded, and is heated and pressed in the laminating direction of the laminated body 26 (for example, 250 to 400 degrees, 1 to 10 MPa, several tens of seconds). I do. By this thermocompression bonding step, the insulating resin base materials 10a to 10d are softened and are brought into close contact with each other so as to sandwich the wiring layer 24 (wiring pattern 20). The interlayer connection material 16 focused on the via hole 14 is sintered by a thermocompression bonding process to become a connection member for connecting the wiring patterns 20 of the respective layers. And the multilayer substrate 100 in which each layer was integrated as shown in FIG.5 (b) is formed through cooling after thermocompression bonding.

  Subsequently, the surface layer 10a is irradiated with laser light from a laser source (not shown), and the opening 12 having the electrode portion 22 as a bottom surface is provided in the surface layer 10a (FIG. 5C). Thereby, the electrode part 22 formed in the inner layer is exposed through the opening 12, and the mounting component can be mounted on the electrode part 22 formed in the inner layer. And the multilayer substrate 100 in this embodiment can be obtained.

(Other embodiments)
Next, another embodiment of the present invention will be described with reference to FIGS. Note that description of parts common to the first embodiment is omitted.

  FIG. 2 is a schematic cross-sectional view showing a cross-sectional structure of the multilayer substrate 101 in the present embodiment. FIG. 2A is an example of the multilayer substrate 101 including a plurality of electrode portions 22b between the resin base materials 10a and 10b. FIG. 2B shows an example in which a BGA package is mounted on the multilayer substrate 101 as the mounting component 30. All the electrodes 31 formed on the bottom surface of the BGA package are soldered to the electrode portion 22b with solder 28.

  FIG. 3 is a schematic cross-sectional view showing a cross-sectional structure of the multilayer substrate 102 in the present embodiment. FIG. 3A is an example of a multilayer substrate 102 that is provided with an electrode portion 22a formed on the surface layer 10a of the resin base material and an electrode portion 22b formed between the resin base materials 10a and 10b. is there. FIG. 3B shows an example in which a BGA package is mounted on the multilayer substrate 102 as the mounting component 30. This shows that it is useful when there is a difference in size between the electrodes 31 and 32 formed on the bottom surface of the BGA package. The electrodes 31 and 32 are both soldered to the electrode portions 22a and 22b by solder 28.

  Although the best mode for carrying out the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. is there.

  For example, an example in which a liquid crystal polymer (LCP) that is a thermoplastic resin is used as a constituent material of the insulating resin substrate 10 has been shown. However, other than that, a thermoplastic resin composed of 65 to 35% of polyetheretherketone (PEEK) and 35 to 65% of polyetherimide (PEI) may be used, and PEEK and PEI are used alone. May be.

  Further, polyethersulfone (PES), polyphenylene ether (PPE), polyethylene naphthalate (PEN), a styrenic resin having a syndiotactic structure or the like may be used alone, or each of them including PEEK and PEI. Any one of them may be mixed and used.

  That is, in the thermocompression bonding step shown in FIG. 5B, the resin base materials can be in close contact with each other with the wiring pattern interposed therebetween, and further, it is necessary for soldering or the like when mounting the mounting component. Any resin having heat resistance can be suitably used.

  Moreover, the multilayer substrate of the present invention can cope with mounting of package parts such as QFP and SOP as well as the BGA package.

1 is a schematic cross-sectional view of a multilayer substrate 100 in a first embodiment of the present invention. It is a schematic sectional drawing of the multilayer substrate 101 in other embodiment of this invention. It is a schematic sectional drawing of the multilayer board | substrate 102 in other embodiment of this invention. It is a figure which shows the outline of the manufacturing process in the manufacturing method of the multilayer substrate 100 of this invention. It is a figure which shows the outline of the manufacturing process in the manufacturing method of the multilayer substrate 100 of this invention. It is a schematic sectional drawing of the conventional multilayer substrate 103.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Insulating resin base material, 10a ... Surface layer, 10b ... 2nd layer, 10c ... 3rd layer, 10d ... 4th layer, 12 ... Opening part, 14 ... -Via hole, 16 ... interlayer connection material (conductive paste), 18 ... protective film, 20 ... wiring pattern, 21 ... metal foil (copper foil), 22 ... electrode part, 24 ..Wiring layer, 26... Laminated body, 28... Solder, 30... Mounted component (BGA package) 31, 32... Electrode of mounted component, 100, 101, 102, 103. substrate,

Claims (6)

A multilayer substrate comprising a laminate in which insulating resin base materials and wiring layers comprising wiring patterns are alternately laminated,
An electrode part to which an electrode of a mounting component is connected to a part of the wiring pattern of the inner layer in the laminate is formed,
The multilayer substrate according to claim 1, wherein the electrode portion is exposed through an opening provided in the resin base material on a surface layer of the laminate.   The multilayer substrate according to claim 1, wherein the size of the electrode portion is larger than the size of the opening.   The multilayer substrate according to claim 1, wherein the resin base material is made of a thermoplastic resin film.   The multilayer substrate according to claim 1, wherein the wiring pattern is formed on one side of the resin base material. A laminating step of alternately laminating an insulating resin base material and a wiring layer formed of a wiring pattern in which an electrode part is formed in part, to form a laminate;
A thermocompression bonding step of thermocompression bonding the laminate in the laminating direction;
An exposure step of removing a predetermined portion of the surface layer of the laminate and exposing the electrode portion of the inner layer of the laminate. In the exposing step,
The method for manufacturing a multilayer substrate according to claim 6, wherein the resin base material is irradiated with laser light to provide an opening, and the electrode is exposed through the opening.

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