JP2002329968A - Method of manufacturing primary laminate for use in manufacture of multilayer printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a primary laminate of about 40 layers, which improves a mass lamination method and which has not been able to be manufactured by a method of prior art. SOLUTION: Upon manufacturing a primary laminate, both of a thermal fusion joint and a grommet fitting joint are used for a joint between laminated layer members so that the inner diameter of a grommet fit insertion hole made in the primary laminate is larger than the outer diameter of a grommet fit body 5 and smaller than the outer diameter of a grommet fit flange 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a primary laminate used for manufacturing a multilayer printed wiring board by hot pressing or the like, and more particularly, to an improvement of a mass lamination method.

[0002]

2. Description of the Related Art A method of manufacturing a multilayer printed wiring board by alternately laminating a plurality of inner core materials having an electric circuit on one or both sides and a plurality of prepregs is known as a multilayer printed wiring board having about 40 layers. Lamination method (pin lamination method), which can be manufactured all at once, and a lamination of about 4 to 8 layers to temporarily create a primary laminate, and then heat press the sandwich between the two copper foils. The nation method (masurami method) is known. In the pin lamination method, holes for positioning are made in the inner core material and prepreg in advance, and copper foil, prepreg, inner core material, prepreg, inner core material, prepreg, and inner core material are formed in reference pins provided on the jig plate. , Prepreg, and copper foil, and then hot pressing. This method has an advantage that a multilayer printed wiring board of about 40 layers can be manufactured at once without passing through a primary laminate.

[0003] However, in the pin-laminating method, a plurality of inner core materials and prepregs are inserted into a plurality of pins set upright on a jig plate. In addition, the prepreg melts and becomes entangled with the pins during the hot pressing in the pin laminating method, so a special tool is required to remove the pins when the manufactured multilayer printed wiring board is removed from the jig plate, and the prepreg melt-hardened residue When a pin is clogged in the pin hole of the jig plate, a special tool is required to remove it. In addition, since the jig plate is manufactured in accordance with the dimensions of the multilayer printed wiring board to be manufactured in the pin lamination method, the types of the jig plate are increased, and there is a disadvantage that the maintenance management is troublesome.

[0004] On the other hand, in the mass lamination method, a plurality of prepregs and an inner layer core material are alternately laminated, and an interface between the prepreg and the inner layer core material is spot-joined to produce a primary laminate first. Next, a method of manufacturing a multilayer printed wiring board by sandwiching the primary laminated body typically between two copper foils and hot-pressing the whole to surface-bond each laminated member. When manufacturing the primary laminate, copper foil may be provided in advance on both surfaces or one surface of the outermost layer, but in any case, the conventional mass lamination method requires each laminated member to be Are roughly classified into the following two types according to the difference in the means for partially joining at the interface. One of them is a heat welding method in which a prepreg and an inner core material are spot-welded by heat welding, and the other is a eyelet method in which each laminated member is spot-joined collectively using eyelets. Here, the spot joining means that the interface between the respective laminated members is locally, in other words,
Partially joined and not surface bonded.
The primary laminated body by the thermal welding method, the adhesive strength between the laminated members is not always sufficient, and when the number of inner layer core materials and prepregs increases, the adhesive strength at the center in the thickness direction of the primary laminated body is further reduced, Peeling easily occurs between the laminated members. On the other hand, since the eyelet method fixes each laminated member with an eyelet that penetrates in the thickness direction of the primary laminate, there is no fear of peeling between the members, but the eyelet cylinder when caulking the eyelet is used. Due to the deformation of the portion, the inner wall of the eyelet hole is likely to be compressed, causing a shift between the members, and this tendency increases as the number of inner core materials and prepregs increases. For these reasons, the number of primary laminates that can be manufactured by the conventional mass lamination method is generally limited to about 12 layers.

[0005]

SUMMARY OF THE INVENTION The present invention is an improvement of the conventional mass laminating method. As a means for spot joining between the layers of the primary laminate, heat welding and eyelet fixing are used together to solve the above-mentioned disadvantages. Provided is a method for manufacturing a primary laminate of about 40 layers, which cannot be manufactured by a conventional method.

[0006]

One method of manufacturing a primary laminate according to the present invention comprises alternately laminating a plurality of prepregs and an inner layer core material, and spot-joining the interface between the laminated members to form a primary laminate. In the method of manufacturing a laminated body, the interface between each laminated member is spot-joined by heat welding, and further, an eyelet is inserted into each of the laminated members and inserted into an insertion hole having an inner diameter equal to the outer diameter of the eyelet body. It is characterized by being inserted and crimping its tip. Another one of the primary laminate production methods according to the present invention is a method for producing a primary laminate by alternately laminating a plurality of prepregs and an inner layer core material and spot-joining an interface between respective laminated members, The interfaces between the respective laminated members are spot-welded by heat welding, and furthermore, each of the laminated members is penetrated, the inner diameter is larger than the outer diameter of the eyelet body, and the eyelet is inserted into the eyelet insertion hole smaller than the flange diameter of the eyelet. It is characterized by caulking the tip.
In any of the above two methods, in the case of spot bonding by eyelets, the prepreg is preheated to a temperature at which the prepreg reaches the C stage and inserted into the insertion hole, or after the eyelet is inserted into the insertion hole, the prepreg is moved to the C stage. This can be heated to a temperature up to and caulking the eyelet tip. If such a method of eyelet heating is adopted, the eyelet bonding portion will be thermally welded as a result, so that spot welding can be omitted by simple thermal welding.

[0007]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing a primary laminate manufactured by a method of the present invention in which a prepreg 1 and an inner layer core material 2 having a circuit pattern formed on both sides are alternately laminated, and reference numeral 3 denotes each laminate. Reference numeral 4 denotes a heat-welded joint that spot-joins the interfaces of the members, and reference numeral 4 denotes an eyelet joint that mechanically spot-joins the respective laminated members. For the sake of convenience, FIG. 1 shows a primary laminate having a six-layer structure in which three prepregs and two inner core materials are used and the prepreg is disposed on the outermost layer. By increasing the number of sheets used, a primary laminate of about 40 layers can be manufactured at once. Although not shown, a copper foil is arranged on one or both surfaces of the outermost layer of the primary laminate, and the copper foil can be spot-joined together with the prepreg 1 and the inner layer core material, as described above. is there. Further, in the primary laminate of FIG. 1, prepregs are respectively arranged on the outermost layers, but according to the method of the present invention, it is also possible to produce a primary laminate in which the inner core layers are respectively located on the outermost layers. In the primary laminate shown in FIG.
Two heat-welded joints and eyelet joints are provided on each of two opposing peripheral edges, but the dimensions of the plate-shaped primary laminate in the XY directions (the magnitude of the two-dimensional spread, Z
The dimension in the direction corresponds to the thickness of the primary laminate. According to (1), any number of heat-welded joints 3 and eyelet joints 4 can be provided at arbitrary positions on the periphery of the primary laminate.

In laminating the individual laminated members, a plurality of inner core materials can be aligned with each other by using a reference pin in a usual manner, and a reference mark previously attached to the inner core material can be used. The position of each layer can be adjusted by optical recognition. Each member to be laminated is provided with an eyelet insertion hole at a predetermined position. The eyelet insertion hole can be drilled in advance in each laminated member before laminating the members, but can also be drilled so as to penetrate each member after lamination. The inner diameter of the eyelet insertion hole is either the same size as the outer diameter of the eyelet body to be inserted here, or one of dimensions larger than the outer diameter of the eyelet body and smaller than the diameter of the eyelet flange. This will be described later.

In order to perform spot joining between the laminated members by heat welding, it is necessary to locally heat the laminated members. As the heating means, direct heating with a soldering iron or the like, which is a common means in the art, or dielectric heating can be arbitrarily adopted. When producing a multilayer primary laminate of eight or more layers, it is preferable to employ dielectric heating.
Each of the laminated members locally shifts from the B stage to the C stage by this heating and is spot-joined. According to the present invention, in addition to the spot joining of the respective laminated members by thermal welding, all the laminated members are spot joined by eyelets penetrating in the thickness direction. This eyelet junction is
This is performed by inserting the body of the eyelet into an eyelet insertion hole that penetrates the stacked members and caulking the tip. As described above, the inner diameter of the eyelet insertion hole can be the same size as the outer diameter of the eyelet body to be inserted, and larger than the outer diameter of the eyelet body and smaller than the diameter of the eyelet flange. It can also be. When the inner diameter of the insertion hole is the same as the outer diameter of the eyelet body, it is preferable that spot welding by heat welding be performed prior to spot welding by eyelets. This is because, if spot bonding by thermal welding is performed in advance, even if the eyelet body is deformed when caulking the eyelets, interlayer displacement between the laminated members can be prevented.

In the case where the inner diameter of the insertion hole is larger than the outer diameter of the eyelet body and smaller than the diameter of the eyelet flange, either the spot welding by heat welding or the spot welding by eyelet is performed first. Or both may be performed simultaneously. FIG.
FIG. 4 is a cross-sectional view showing a state in which the eyelets are inserted into an insertion hole having a dimension larger than the outer diameter d of the eyelet body 5 and smaller than the diameter D of the eyelet flange 6. The clearance between the outer periphery of the eyelet body and the inner wall of the insertion hole is preferably selected according to the size of the outer diameter of the eyelet body and the width of the flange, but is generally about 100 to 400 microns. Selected by range. The presence of the clearance prevents or reduces pressure on the inner wall of the insertion hole due to the deformation even if the eyelet body deforms when the eyelet tip is swaged. For the eyelet, a metal eyelet made of brass (brass), aluminum or the like can be used, and a synthetic resin eyelet mixed with metal powder can be used.

In the eyelet bonding of the present invention, regardless of the presence or absence of the above-described clearance, heat can be applied to the eyelets to raise the temperature to a temperature at which the prepreg and / or the inner core material reaches the C stage. The heat may be applied to the eyelets either before or after inserting the eyelets into the insertion hole. As the means for heating the eyelets, when the eyelets are a good electrical conductor, energizing heating,
When direct heating, high-frequency induction heating, etc. are insulators,
Direct heating, high-frequency dielectric heating and the like can be arbitrarily adopted. The use of the eyelet welding method, which applies heat to the eyelets to perform eyelet bonding, naturally allows the vicinity of the inner wall of the insertion hole to be liquefied by the heat applied to the eyelets and transferred to the C stage. The eyelet joint is thermally welded. The timing of performing the caulking operation of the eyelet tip may be either before or after the vicinity of the insertion hole shifts to the C stage.
If the caulking operation is performed before moving to the stage, the eyelet body is in a state surrounded by liquefied resin, so if the eyelet body is deformed, the deformation is buffered with liquefied resin, and the laminated member No deviation occurs. The primary laminate illustrated in FIG. 1 has a heat-welded joint 4 and an eyelet joint 5 at its peripheral edge. However, if the eyelet-weld joint method described above is adopted, the heat-welded joint using no eyelet is used. Part or all of the part 3 can be replaced with a joint formed by the eyelet welding method, and similarly, part or all of the eyelet bonded part 4 without heating can be replaced with a joint formed by the eyelet welding method. Can be.

[0012]

Since the method of the present invention is a method of joining each laminated member by heat welding and eyelet joining, a multilayer primary laminate of about 40 layers, which cannot be substantially manufactured by the conventional mass lamination method, is used. It can be manufactured at once without fear of peeling or displacement between the laminated members.

[Brief description of the drawings]

FIG. 1 is a perspective view of a primary laminate manufactured according to an embodiment of the method of the present invention.

FIG. 2 is a partially enlarged sectional view near an eyelet insertion hole for explaining eyelet bonding employed in the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pre-preg 2 Inner-layer core material 3 Heat welding joint 4 Eyelet joint part 5 Eyelet body part 6 Eyelet flange part 7 Eyelet tip part

Continued on front page F-term (reference) 4F100 AT00B AT00D BA08 BA32 DH01A DH01C DH01E EC031 EC032 EJ081 EJ262 EJ331 EJ421 EJ422 EJ951 GB43 JK06 JL01 JL02 5E346 AA12 AA26 CC08 CC32 DD02 DD12 EE04 EE16 EE06 EE09

Claims (9)

[Claims] 1. A method of manufacturing a primary laminate by laminating a plurality of prepregs and an inner layer core material alternately and partially joining an interface between the laminated members, wherein the interface between the laminated members is thermally welded. Is partially joined, and furthermore, it is characterized in that the eyelets are inserted and caulked into an insertion hole having an inner diameter equal to the outer diameter of the eyelet body, which is a through hole formed in each laminated member. A method for producing a primary laminate. 2. Inserting the eyelets preheated to the temperature at which the prepreg reaches the C stage into the insertion hole, or heating the eyelets inserted into the insertion hole to the temperature at which the prepreg reaches the C stage and fixing the eyelet tip. 2. The method according to claim 1, further comprising the step of: 3. A method of manufacturing a primary laminated body by alternately laminating a plurality of prepregs and an inner core material and partially bonding an interface between the laminated members, wherein the interface between the laminated members is thermally welded. The prepreg is pre-heated to a temperature at which the prepreg reaches the C-stage in an insertion hole having an inner diameter equal to the outer diameter of the eyelet body, which is a through hole formed in each laminated member without being partially joined by A method for manufacturing a primary laminate, comprising inserting the inserted eyelets into an insertion hole, or heating the eyelets inserted into the insertion hole to a temperature at which a prepreg reaches a C stage, and caulking the eyelet tip. 4. The method according to claim 2, wherein the heating means for the eyelets uses any one of direct heating, electric heating, dielectric heating and induction heating.
Or the method of claim 3. 5. A method of manufacturing a primary laminate by alternately laminating a plurality of prepregs and an inner layer core material and partially bonding an interface between the laminated members, wherein the interface between the laminated members is thermally welded. The eyelet is inserted into an insertion hole having an inner diameter larger than the outer diameter of the eyelet body portion and smaller than the diameter of the eyelet flange portion. A method for producing a primary laminate, comprising crimping a tip portion. 6. Inserting the eyelets preheated to the temperature at which the prepreg reaches the C stage into the insertion hole, or heating the eyelets inserted into the insertion hole to the temperature at which the prepreg reaches the C stage, and fixing the eyelet tip. 6. The method according to claim 5, wherein the tightening is performed. 7. A method of manufacturing a primary laminate by alternately laminating a plurality of prepregs and an inner core material and partially bonding an interface between the laminated members, wherein the interface between the laminated members is thermally welded. The prepreg is inserted into the through hole formed in each laminated member without being partially joined, the inner diameter of which is larger than the outer diameter of the eyelet body, and the diameter of the eyelet flange, which is smaller than the diameter of the eyelet flange. Inserting the eyelets preheated to the maximum temperature into the insertion hole, or heating the eyelets inserted into the insertion hole to a temperature at which the prepreg reaches the C stage and caulking the eyelet tip portion, Production method. 8. The heating means for the eyelets uses one of direct heating, electric heating, dielectric heating and induction heating.
Or the method of claim 7. 9. A primary laminate in which a plurality of prepregs and an inner core material are alternately laminated between two copper foils, and the eyelet joints of each laminated member are thermally welded.