JP2006222238A - Internal circuit member, multilayer wiring circuit board using same, and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To diffuse heat left after a temporarily welding operation has been carried out, to restrain resin contained in prepreg from being unnecessarily melted, and to restrain projections which are produced from the melted resin on the internal circuit member from occurring, by providing a heat diffusing part between a circuit pattern and a temporarily welded part independently of the circuit pattern in an internal circuit member used for a multilayer wiring circuit board. <P>SOLUTION: The prepreg and the internal circuit member are laminated, the prepreg is temporarily welded to the adjacent internal circuit member to form a laminate, and the multilayer wiring circuit board is formed of the laminate. In the internal circuit member used for the multilayer wiring circuit board, a circuit pattern is provided, at least, on either of the surfaces of the internal circuit member, a temporarily welded part is also provided, at least, on the peripheral edge of either of the surfaces of the internal circuit member, and a heat diffusing part is provided between the circuit pattern and the temporarily welded part independently of the circuit pattern. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a member for an inner layer circuit, a multilayer wiring circuit board using the same, and a method for manufacturing the same, and more specifically, generation of a convex portion of the outermost metal foil during secondary lamination when manufacturing a multilayer wiring circuit board. The present invention relates to an inner layer circuit member that suppresses the above, a multilayer wiring circuit board using the same, and a method for manufacturing the same.

  As a method for producing a multilayer wiring circuit board, a plurality of inner layer circuit members are stacked through a prepreg, and a laminate obtained by partially temporarily welding the prepreg to an adjacent inner layer circuit member is formed by heating and pressing. By doing so, a method is known in which each prepreg is entirely welded to an adjacent inner layer circuit member.

  For example, in Patent Document 1, in the manufacturing method described above, in order to manufacture a multilayer printed wiring board having a high-accuracy circuit pattern by preventing the displacement of the inner layer material, heat pressing is performed from the start of heat pressing. After the primary pressure of 0.5 to 1.0 MPa, the secondary pressure of 1.5 to 2.5 MPa is used, and the pressure increase from the primary pressure to the secondary pressure is performed over 20 to 30 minutes. The timing for reaching the secondary pressure is between the time when the product temperature is raised at 1 to 3 ° C./min and 10 minutes before the point when the resin of the prepreg reaches the minimum melt viscosity. A method for producing a multilayer printed wiring board characterized by the above is disclosed.

Further, Patent Document 2 discloses that a peripheral portion of a circuit board (inner layer board) on which a circuit is formed for the purpose of firmly bonding with an insulator when a primary laminated board is laid up on a printed wiring board. A peripheral copper foil part having a defective part is formed, and the peripheral copper foil part is separated from the peripheral copper foil part in a non-contact state in the defective part and has a defective part in the peripheral part. An inner layer board in a printed wiring board is formed and separated from the peripheral copper foil part in a non-contact state in the defect part and is provided with a separated copper foil part formed of a plurality of copper foils It is disclosed.
JP 2004-235271 A JP 2001-28479 A

  However, when a multilayer wiring board is manufactured by the manufacturing method of Patent Document 1 and the manufacturing method using the inner layer plate of Patent Document 2, the residual heat at the time of temporary welding does not stagnate in the temporary welding part and the periphery of the temporary welding part. In some cases, the resin of the prepreg around the temporary welded portion may be softened and melted. Therefore, the resin of the prepreg has melted more than necessary for temporary welding, and the peripheral portion of the temporary welding portion has risen and sometimes has a convex portion. Such convex portions cause displacement and distortion between the members for the inner layer circuit during the heat and pressure molding for the secondary lamination, and cause the positioning accuracy of the stacked layers to be lowered.

  Further, the presence of the convex portion is left as it is when the metal foil is laminated on the outermost layer during the heat-press molding of the secondary lamination. become. Such convex portions may cause a decrease in productivity in the heat and pressure molding process. That is, usually, when manufacturing a multilayer wiring board, a plurality of preliminarily welded laminates are stacked and subjected to a heat pressing process using a laminating press or the like. Manufacturing at the same time. In such a process, if there are convex portions in the outermost layer of each laminate, if they are stacked, the entire laminate as shown in FIG. There was a problem that a multilayer wiring board could not be obtained.

  Therefore, as a result of intensive studies to solve the above problems, the present inventors have obtained a multilayer wiring circuit obtained by further heat-pressing a laminate obtained by temporarily welding a prepreg and an adjacent inner layer circuit member. In a member for an inner layer circuit used for manufacturing a substrate, a heat diffusion part is formed outside the formed circuit pattern, and the heat diffusion part is arranged independently of the circuit pattern between the circuit pattern and the temporary welding part. As a result, the present inventors have found that the residual heat at the time of temporary welding is diffused and the above problem can be solved.

  That is, claim 1 of the present invention is an inner layer circuit member for a multilayer wiring circuit board obtained by using a laminate in which a prepreg and an inner layer circuit member are laminated and the prepreg is temporarily welded to an adjacent inner layer circuit member. The circuit pattern includes a circuit pattern in at least one surface of the inner layer circuit member and a portion that can be temporarily welded to a peripheral portion in the surface, and the circuit pattern is interposed between the circuit pattern and the portion that can be temporarily welded. A member for an inner layer circuit, characterized in that a thermal diffusion portion is formed independently of the inner layer circuit. In this way, in the inner layer circuit member used for the multilayer wiring circuit board, the heat diffusion portion is formed independently of the circuit pattern between the circuit pattern and the temporary welded portion, thereby diffusing the residual heat at the time of temporary welding. It is possible to prevent the resin of the prepreg from being melted more than necessary. Therefore, generation | occurrence | production of the convex part by melting of the said resin on the member for inner layer circuits can be suppressed. In addition, since the thermal diffusion portion is disposed between the circuit pattern and the temporary welding portion, it is difficult for the residual heat at the time of temporary welding to be transmitted to the circuit pattern, and problems such as warping of the circuit pattern due to the residual heat, distortion, etc. There is also an effect that can be suppressed.

  Further, by forming the pattern so that the thermal diffusion part becomes a continuous body, the residual heat at the time of temporary welding can be efficiently diffused throughout the thermal diffusion part (Claim 2).

  Furthermore, in the pattern, by forming the pattern so that the shape of the pattern is deficient in a lattice shape or a dot shape, the remaining heat at the time of temporary welding can be further uniformly diffused throughout the thermal diffusion portion (claim). Item 3).

  Further, in an inner layer circuit member for a multilayer wiring circuit board obtained by using a laminate in which a prepreg and an inner layer circuit member are laminated and the prepreg is temporarily welded to an adjacent inner layer circuit member, the inner layer circuit member A circuit pattern is provided in at least one surface, and a temporary weld portion is provided at a peripheral edge portion in the surface, and a thermal diffusion portion is formed independently of the circuit pattern between the circuit pattern and the temporary weld portion. When a multilayer wiring circuit board is manufactured using an inner layer circuit member characterized by the above, a plurality of sets of temporarily welded laminates are stacked, and a plurality of sets of multilayer wiring boards are simultaneously manufactured using a stacking press or the like. Even in such a case, each multilayer wiring board can be manufactured to be homogeneous.

  Furthermore, in the said manufacturing method, it is preferable that the space | interval between the said thermal diffusion part and a temporary welding part is 0-10 mm (Claim 5). By maintaining such an interval, the residual heat at the time of temporary welding can be efficiently diffused by the thermal diffusion section.

  Moreover, in the said manufacturing method, when it is formed so that the width | variety of the transversal direction of the said thermal-diffusion part may be 4-10 times the width | variety of the transversal direction of a temporary welding part, the residual heat at the time of temporary welding is carried out. Appropriate thermal diffusion can be achieved (claim 6).

  Furthermore, in the manufacturing method, by arranging the inner layer circuit member so that the thermal diffusion portion faces the prepreg at the time of temporary welding, it is more effective that the resin of the prepreg is melted more than necessary due to residual heat at the time of temporary welding. (Claim 7).

  In addition, the multilayer printed circuit board obtained by using the manufacturing method has no deviation between the laminated layers, and enables precise secondary processing (claim 8).

  In an inner layer circuit member used for manufacturing a multilayer wiring circuit board, the inner layer circuit member has a circuit pattern in at least one surface of the inner layer circuit member and a portion that can be temporarily welded to a peripheral portion in the surface, and the circuit pattern and the Since the thermal diffusion part is formed independently of the circuit pattern between the part that can be temporarily welded, the residual heat at the time of temporary welding is diffused by the thermal diffusion part. And, since the residual heat of the temporary welding is transmitted to the thermal diffusion part, the heat is not stagnated only around the temporary welding part, and the prepreg resin around the temporary welding part is prevented from being melted more than necessary. it can. As a result, convex portions formed by the resin of the prepreg melted more than necessary on the inner layer circuit member are less likely to occur, and between the inner layer circuit members when performing heat and pressure molding for secondary lamination. Generation | occurrence | production of the convex part in a shift | offset | difference and a distortion, and the metal foil of outermost layer can be suppressed. Therefore, even when a plurality of sets of multilayer printed circuit boards are simultaneously heat-press molded, a homogeneous multilayer printed circuit board can be manufactured.

  The present invention provides an inner layer circuit member for a multilayer wiring circuit board obtained by using a laminate in which a prepreg and an inner layer circuit member are laminated and the prepreg is temporarily welded to an adjacent inner layer circuit member. There is a circuit pattern in at least one surface of the member and a part that can be temporarily welded to the peripheral edge in the surface, and thermal diffusion is performed independently from the circuit pattern between the circuit pattern and the part that can be temporarily welded. The present invention relates to an inner layer circuit member characterized in that a portion is formed.

  Here, the circuit pattern means a portion where a wiring circuit pattern according to the purpose is formed by using a known wiring circuit pattern forming method such as etching on a known inner layer circuit member, and thermal diffusion. The part means a metal foil part that is arranged outside the circuit pattern and separated from the circuit pattern by the etching process or the like.

  In addition, as said well-known printed wiring board, the wiring circuit board which has a layer (conductor layer) coat | covered with metal foil layers, such as copper foil, in order to form a circuit pattern in the single side | surface or both surfaces of an insulating layer is mentioned. Specifically, R-1766, R-1566, etc. manufactured by Matsushita Electric Works, Ltd. can be mentioned.

  Moreover, the part which can be temporarily welded is a part which can be temporarily welded to the prepreg present in the peripheral edge in at least one surface of the inner layer circuit member, and means a part having no metal foil.

  In addition, when a thermal diffusion part is provided in the surface which does not oppose a prepreg, the part which projected the part corresponded to the part which can be temporarily welded on the back surface of the member for inner layer circuits is also included.

  The inner layer circuit member of the present invention has a circuit pattern and a heat diffusion part arranged outside the circuit pattern outside the circuit pattern in a known inner layer circuit member or the like, and further, the heat diffusion part includes the circuit pattern and the inner layer circuit. It arrange | positions between the parts which can be temporarily welded of the peripheral part in the surface of at least one of the members for use. Thus, by forming a thermal diffusion part independently from a circuit pattern, the residual heat of the thermal welding produced in the temporary welding is thermally diffused by the thermal diffusion part. Therefore, the remaining heat does not stagnate only around the temporary welded portion, and the prepreg resin around the temporary welded portion can be prevented from being melted more than necessary. Moreover, as a result, it becomes difficult to form a convex part on the substrate, and the deviation and distortion between the members for the inner layer circuit and the convex part in the outermost layer metal foil at the time of heat-press molding for the secondary lamination. Occurrence can be suppressed. Furthermore, since the thermal diffusion part is disposed between the circuit pattern and the portion capable of being temporarily welded, the residual heat of heat given for temporary welding is diffused by the thermal diffusion part in the vicinity of the temporary welded part. It is possible to suppress the transfer of heat to the circuit pattern in which the wiring circuit is formed. For this reason, warpage, distortion, and the like of the formed wiring circuit itself can be suppressed.

  As the wiring circuit pattern of the circuit pattern, a known circuit pattern formed on a printed wiring board or the like is selected according to the purpose and is not particularly limited.

  On the other hand, the thermal diffusion part is formed independently of the circuit pattern.

  As for the arrangement of the thermal diffusion portion, in the inner layer circuit member surface, it is substantially parallel to the vertical side or the horizontal side of the inner layer circuit member between the portion where the circuit pattern is formed and the portion to be temporarily welded. It is not particularly limited, for example, provided on both sides (see FIG. 1), or formed in a frame shape surrounding a portion where a circuit pattern is formed (see FIG. 2). Further, it may be provided only in the vicinity of a plurality of portions to be temporarily welded (see FIG. 3).

  Further, the shape of the thermal diffusion portion is not particularly limited as long as the effect of the present invention is achieved. Specifically, for example, a rectangular shape with no pattern formed therein, a rectangular shape as shown in FIG. 4A or a dot shape as shown in FIG. First, various patterns are formed. When various patterns are formed in the thermal diffusion part, the area ratio of the metal foil part having high thermal conductivity can be adjusted, and the thermal diffusion efficiency of the thermal diffusion part can be adjusted as desired. Therefore, when a pattern that leaves the metal foil part at a high rate by etching or the like is formed in the heat diffusion part, the heat diffusion efficiency becomes relatively high, and the pattern that leaves the metal foil part at a low rate is heated. When it is formed in the diffusion portion, the heat diffusion effect can be adjusted to be relatively low.

  In addition, as a size of the entire heat diffusion portion, for example, when the heat diffusion portion is rectangular, the length of the short side thereof is 20 to 100 mm, and further 20 to 40 mm. In the case where the thermal diffusion portions are arranged, the total of the long sides) is preferably about 70 to 100% of the entire length of the substrate from the viewpoint of thermal diffusion efficiency. That is, when the total length of the substrate is 610 mm, it is preferably about 427 to 610 mm (see FIG. 5).

  Further, when the heat diffusing portion is rectangular, the width in the short direction is 4 to 10 times the width in the short direction of the temporary welded portion, and more preferably about 4 to 6 times. It is preferable from the viewpoint of efficiency.

  In addition, as a lattice-like pattern formed in the thermal diffusion portion, the line width forming the lattice is preferably about 1 to 3 mm, and the length of the vertical and horizontal sides of the window frame formed by the lattice is 1 to 1. About 5 mm is preferable. By forming the lattice in such a form, a more appropriate thermal conductivity can be imparted to the thermal diffusion portion.

  In addition, as the pattern of the said thermal diffusion part, it is preferable that the pattern is formed so that it may become a continuous body, in order for heat conduction to the metal foil part without interruption. This is because when the metal foil part in the heat diffusion part is cut off, the heat transfer efficiency is lowered and the heat diffusion becomes difficult.

  It is preferable that the heat diffusing part is appropriately adjusted and arranged in a range that achieves the effect of the present invention in accordance with the size, shape, etc. of the entire inner layer circuit member and the size, shape, and number of the temporary welded parts. Specifically, the arrangement is preferably as follows.

  It is preferable that the arrangement | positioning space | interval of a thermal-diffusion part and a temporary welding part is arrange | positioned so that it may have an interval of 0-10 mm between both, and 1-5 mm. When the distance is 0 mm, that is, when the end of the thermal diffusion portion and the end of the temporary welding portion overlap, the heat dissipation effect tends to be somewhat high, so a thermal diffusion portion with a relatively small area is provided. It is preferable. Moreover, when it exceeds 10 mm, there exists a tendency for the heat dissipation effect to become low.

  Furthermore, as the area of the thermal diffusion part, if the area of the temporary welded part is large, the heat of welding and the generated residual heat increase accordingly, so that it is preferably formed relatively large, conversely, the temporary welded part If the area is small, the remaining heat is reduced by that amount. Therefore, it is preferable to form a relatively small area from the viewpoint of thermal diffusion efficiency.

  The number of the thermal diffusion parts is appropriately selected according to the size and the number of the temporary welding parts, but even if only one continuous heat radiation part as shown in FIG. 2 is provided, the wiring as shown in FIG. One each may be provided on the side surface of the substrate, or a number corresponding to the number of temporary welds may be provided in the vicinity of the temporary welds as shown in FIG.

  The thermal diffusion portion may be provided on either one side or both sides as required, but at least an inner layer facing the prepreg in order to suppress melting of the prepreg resin more than necessary in the temporary welding of the prepreg resin. It is preferably provided on the surface of the circuit member.

  The method for producing the inner layer circuit member of the present invention is not particularly limited, and a conventional wiring circuit forming method for providing a wiring circuit by etching a metal foil of a known printed wiring board can be used.

  The thermal diffusion portion in the inner layer circuit member of the present invention is preferably formed when the circuit pattern is formed by etching or the like. Various pattern formations in the thermal diffusion portion are also formed by the same etching process as that for forming the wiring circuit pattern.

  As another method for forming the thermal diffusion portion, there is also a method for forming the thermal diffusion portion by forming a metal film having a desired shape by plating or the like on a portion where the metal foil is removed by etching processing or the like. Can be selected.

  The member for an inner layer circuit of the present invention produced as described above is laminated via a prepreg and used for the production of a multilayer wiring circuit board.

  The prepreg used in the present invention is not particularly limited, and a known prepreg obtained by impregnating a base material conventionally used for producing a multilayer printed circuit board with a resin is used.

  Examples of the base material constituting the prepreg include inorganic fibers such as glass, synthetic resin fibers such as polyester, polyamide, polyacryl, and polyimide, or woven fabrics, nonwoven fabrics, and papers of natural fibers such as cotton.

  Examples of the resin constituting the prepreg include, for example, epoxy resin-based, phenol resin-based, polyimide resin-based, unsaturated polyester resin-based, polyphenylene ether-based, thermosetting resin compositions such as modified products and mixtures. Etc.

  As a manufacturing process of a multilayer wiring circuit board, the following processes are generally performed.

  That is, at least one inner layer circuit member including the inner layer circuit member of the present invention is laminated via a prepreg, and each inner layer circuit member is temporarily welded to an adjacent prepreg to obtain a laminate. Next, after a metal foil is further laminated on the surface of the laminate through a prepreg, a multilayer wiring circuit board is formed by overall welding by heat and pressure molding.

  More specifically, it is performed as follows. First, at least one inner layer circuit member including the inner layer circuit member of the present invention is stacked via a prepreg. For example, when an inner layer circuit member having circuit patterns on both surfaces is used and five or more inner layer circuit members are used, a multilayer wiring circuit board having ten or more layers of wiring circuit patterns can be obtained.

  The adjacent inner layer circuit member and the prepreg are in contact with each other over the entire surface, and the inner layer circuit member is overlapped at an accurate position so as not to be displaced in a direction parallel to the surface direction. Further, by providing a laminating guide hole at the end of the inner layer circuit member and the prepreg, and arranging a fixing pin so as to penetrate the laminating guide, the inner layer circuit member is prevented from being displaced.

  As shown in FIG. 6, the plurality of inner layer circuit members stacked via the prepreg are partially pressed onto the adjacent inner layer circuit member 2 by heating and pressing a part of the prepreg 1. The laminate 14 is obtained by temporarily welding and temporarily fixing the adjacent inner layer circuit members.

  As a method of heating and pressurizing a part of the prepreg, in FIG. 6, there are a plurality of temporary welding portions 13 of the inner layer circuit member 2 located in the uppermost layer and temporary welding portions 13 of the inner layer circuit member 2 located in the lowermost layer. The heater jigs 113 are arranged in contact with each other, and the plurality of inner layer circuit members 2 stacked via the prepreg 1 are sandwiched and pressed by the heater jigs 113 arranged to face each other vertically. Heat while. Thereby, the part (part facing the temporary welding part 13) pinched | interposed by the heater jig 113 of the prepreg 1 is hardened, the prepreg 1 is welded to the temporary welding part 13 of the adjacent inner layer circuit member 2, and it adjoins. The inner circuit members 2 are temporarily fixed. And the laminated body 14 used for a heat press molding can be formed by temporarily fix | stop the plurality of inner-layer circuit members 2 laminated | stacked through the prepreg 1 in this way.

As the area of the inner layer circuit member abutting portion (tentative welding portion) 80～160Mm ² further heater fixture 113, it is preferable to use those in the range of 100~160mm ^2.

  Moreover, the temporary welding part is formed in the peripheral part in the surface of the member for inner layer circuits. Therefore, it may be formed in contact with each side around the inner layer circuit member. However, when the resin of the prepreg at the time of temporary welding is melted out from the inner layer circuit member to the periphery thereof, it is preferable that the resin is disposed with an interval of about 10 mm from the peripheral portion in order to affect the dimensional accuracy and the like. .

  Examples of the heater jig include those heated by applying ultrasonic waves to the prepreg by ultrasonic vibration welding, and those heated by an electric heater.

  The heating condition is not particularly limited as long as the temporary welding can be performed, and is selected according to the type of the prepreg, but is usually about 170 to 300 ° C., more preferably about 250 to 300 ° C. for 10 to 120 seconds, and further 20 It is preferable to be set to ˜60 seconds. Moreover, when applying ultrasonic vibration, it is preferable that the frequency shall be 10-50 kHz, and pressurization and ultrasonic vibration application time shall be 10-120 seconds. Further, the pressure applied by the heater jig at the time of temporary welding is not particularly limited as long as the temporary welding can be performed. For example, when an epoxy resin thermosetting resin composition is used as a prepreg, the pressure is usually 0.4. About 1 MPa.

  Conventionally, the residual heat generated during the temporary welding is transmitted not only to the temporary welded portion but also to the periphery of the temporary welded portion, and the prepreg resin in the peripheral portion melts more than necessary, so that the periphery of the temporary welded portion rises and protrudes. The inner layer circuit member was misaligned or distorted during the heat and pressure molding by the convex portion, and the multilayer circuit board was manufactured using the inner layer circuit member of the present invention. In this case, these phenomena can be suppressed.

  Next, the obtained laminate 14 is formed by laminating the metal foil 3 on the both surfaces of the outermost inner layer circuit member 2 via another prepreg 1 (see FIG. 7). Here, in the laminate 14, the prepreg 1 and the metal foil 3 are overlapped with the fixing pin being removed from the stacking guide hole. Further, the surface of the laminate 14, the prepreg 1 and the metal foil 3 are in contact with each other over the entire surface.

  The laminate 14 (foil laminate 15) on which the metal foil 3 is laminated is subjected to heat and pressure molding. That is, the prepreg 1 and the inner layer circuit member 2 adjacent thereto are welded as a whole, and the prepreg 1 and the metal foil 3 adjacent thereto are welded and cured as a whole. In this way, a plurality of inner layer circuit members 2 and the metal foil 3 are integrated and laminated by curing the prepreg 1 to form a multilayer wiring circuit board.

  Specifically, as shown in FIG. 7, the foil laminate 15 is heat-pressed and sandwiched between a pair of pressure plates 16 and 16.

  In addition, it is preferable that the foil laminated body 15 is pressure-reduced before the said heat press molding. This is because gas such as air in the foil laminate 15 remains in the multilayer printed circuit board until after the heat and pressure molding, and the generation of voids is suppressed. That is, after the foil laminate 15 is disposed between the pair of pressure plates 16 and 16, the atmosphere of the foil laminate 15 is reduced by evacuation while the foil laminate 15 is not pressurized with the pressure plates 16 and 16. For example, the foil laminate 15 can be subjected to reduced pressure treatment by holding the laminate 15 for 30 to 60 minutes in a reduced pressure state of 1.3 to 6.7 kPa (10 to 50 Torr).

  The foil laminate 15 subjected to the decompression process in this way is then heated and pressurized.

  Conditions for heating and pressing are not particularly limited, and conditions for forming a normal multilayer wiring circuit board can be employed. Specifically, a heating temperature of 170 to 200 ° C., a pressing pressure of 2 to 4.9 MPa, and a heating time of 150 to 200 minutes are selected. Further, the heating / pressurizing conditions may be programmed and performed under multistage conditions.

  In the heat and pressure molding process, when a conventional inner layer circuit member is used, the convex portion generated during the temporary welding is transferred to the outermost metal foil, and the convex portion is generated in the outermost layer. However, when the inner layer circuit member of the present invention is used, the occurrence of such convex portions on the outermost layer can be suppressed.

  In addition, the said heat press molding usually heat-press-molds at the same time by stacking several sets of multilayer wiring circuit boards, usually about 10 to 20 sets of laminates through a metal separator, in order to improve productivity. Is done. At this time, when a convex portion is generated in the outermost layer in each laminate, the laminate is inclined and distorted as a whole due to the presence of the convex portions stacked as shown in FIG. It becomes impossible to heat and press uniformly, and the thickness of the multilayer circuit board to be obtained, the adhesive strength of each layer, and dimensional accuracy may be inhomogeneous.

  In the case of manufacturing a multilayer wiring circuit board using the inner layer circuit member of the present invention, the inclination can be suppressed, and even when a plurality of sets of multilayer wiring circuit boards are manufactured at the same time, a homogeneous multilayer wiring circuit board can be obtained. Obtainable.

  Hereinafter, the method for producing a multilayer printed circuit board according to the present invention will be described in more detail with reference to examples. This example is only an example of an embodiment of the present invention.

In this example, the raw materials used are shown below.
Prepreg: “R-1661GG 0.1t” (FR-4 prepreg manufactured by Matsushita Electric Works, Ltd., size 510 × 610 mm, thickness 0.1
mm, resin content 52%)
Inner layer circuit member: Double-sided copper-clad laminate ("R-1766", FR- manufactured by Matsushita Electric Works Co., Ltd.)
4 cores, size 510 x 610mm, thickness 0.1mm, copper foil thickness
35μm)
Metal foil: copper foil having a size of 510 × 610 mm and a thickness of 12 μm

  A circuit pattern and a heat diffusion portion are formed on one side of the inner layer circuit member in the arrangement and shape as shown in FIG. 9A (hereinafter, the surface is also referred to as a heat diffusion portion formation surface). In 9 (a), the arrangement and shape without the thermal diffusion portion 20 were formed by a normal etching process. Note that no pattern is formed inside the thermal diffusion portion.

  Next, the inner layer circuit member and the prepreg were superposed in the layer configuration shown in FIG. 10, and an ultrasonic vibration heating device (heater jig size (4 × 20 mm)) was arranged as shown in FIG.

In the layer configuration in FIG. 10, the two inner layer circuit members 41 and 44 are arranged so that the heat diffusion portion forming surfaces do not face the prepregs 42 and 43, respectively.
Next, as shown in FIG. 6, the heater jig 113 was brought into contact with and pressed against the temporary welding portion 13, and the prepreg was partially welded to each of the inner layer circuit members to temporarily fix the laminate 14. In the temporary welding process at this time, the heater jig 113 is brought into contact with the surface end portions of the outermost inner layer circuit members 41 and 44 in FIG. 10 at a pressure of 6 KPa, and each inner layer circuit member corresponding to the contact portion and A part of each prepreg was heated at a welding set temperature of 300 ° C. for 30 seconds.

  Next, a prepreg was further stacked on both surfaces of the laminate 14, and a metal foil was stacked on the outside of the stacked prepreg to obtain a foil laminate 15.

  Then, as shown in FIG. 7, the obtained foil laminate 15 is disposed between a pair of pressure plates 16, and the foil laminate is sandwiched between the pair of pressure plates 16, so that the thickness 1 is obtained. A multilayer printed circuit board having a thickness of 0.0 mm was manufactured.

  The heating and pressing conditions were a pressure plate temperature of 180 ° C., a pressure of 2.9 MPa, and a pressing time of 180 minutes.

The obtained multilayer printed circuit board was evaluated as follows.
(Number of convex parts generated): Observe both sides of 140 multilayer wiring boards and generate convex parts on metal foil
The number of multilayer wiring boards in use was counted.

  The results are shown in Table 1.

  The process was performed in the same manner as in Example 1 except that a pattern as shown in FIG. 9B was formed inside the thermal diffusion part. The evaluation results are shown in Table 1.

  The same procedure as in Example 2 was performed except that the heat diffusion portion forming surface was arranged so as to face the prepregs 42 and 43 in FIG. The evaluation results are shown in Table 1.

Comparative Example 1

  This was carried out in the same manner as in Example 1 except that an inner layer circuit member having no heat diffusion portion formed on both sides was used. The evaluation results are shown in Table 1.

  In Comparative Example 1 using the inner layer circuit member not provided with the heat diffusing portion, the prepreg resin was melted more than necessary due to the residual heat at the time of temporary welding, and there were 140 multilayer wiring circuit boards in which the convex portions were generated. 22 sheets were also obtained.

  On the other hand, in Example 1, the thermal diffusion part in which the pattern is not formed is provided. Therefore, the thermal conductivity of the thermal diffusion part itself is high. However, since the heat diffusion portion forming surface is formed on the back side of the surface facing the prepreg at the time of temporary welding, the residual heat at the time of temporary welding is appropriately diffused, and the convex portion is not generated.

  Further, in Example 2, in the inner layer circuit member having the heat diffusion part in which the lattice pattern is formed, the surface where the heat diffusion part forming surface faces the prepreg at the time of temporary welding as in Example 1 Therefore, there was little diffusion of the residual heat, and convex portions were generated when the number of members for the test inner layer circuit was small.

  Furthermore, in Example 3, in the inner layer circuit member having the thermal diffusion portion in which the lattice pattern is formed, the thermal diffusion portion forming surface is formed on the surface facing the prepreg during temporary welding. The residual heat at the time of temporary welding was moderately diffused, and no convex portion was generated.

  From the results of Comparative Example 1 and Examples 1 to 3, it can be seen that the provision of the thermal diffusion portion in the present invention can significantly suppress the occurrence of the convex portion. Furthermore, it can be seen that by adjusting the shape and arrangement position of the thermal diffusion portion, the degree of melting of the resin of the prepreg can be freely adjusted, and the occurrence of convex portions can be suppressed.

It is a schematic diagram which shows an example of arrangement | positioning of the thermal-diffusion part in the member for inner layer circuits of this invention. It is a schematic diagram which shows an example of arrangement | positioning of the thermal-diffusion part in the member for inner layer circuits of this invention. It is a schematic diagram which shows an example of arrangement | positioning of the thermal-diffusion part in the member for inner layer circuits of this invention. It is a schematic diagram which shows the shape of the thermal diffusion part in the member for inner layer circuits of this invention. It is a schematic diagram which shows an example of arrangement | positioning / a dimension of the thermal diffusion part in the member for inner layer circuits of this invention. It is a schematic diagram which shows the temporary welding process in this invention. It is a schematic diagram which shows the heating-pressing process in this invention. It is a schematic diagram which shows the overlap of a multilayer wiring circuit board. It is a schematic diagram which shows the arrangement pattern of the circuit pattern part of the member for inner layer circuits in an Example, a thermal-diffusion part, and a temporary welding part. It is a schematic diagram which shows the layer structure of the laminated body temporarily welded in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 42, 43 Prepreg 2, 41, 44 Inner layer circuit member 3 Metal foil 4 Circuit pattern part 5 Convex part 6 Multilayer wiring circuit board 10 Lamination guide hole 11 Fixing pin 13 Temporary welding part 14 Laminate 15 Foil laminate 16 Pressure plate 20 Heat diffusion part 113 Heater jig

Claims (8)

In an inner layer circuit member for a multilayer wiring circuit board obtained by using a laminate in which a prepreg and an inner layer circuit member are laminated and the prepreg is temporarily welded to an adjacent inner layer circuit member,
A circuit pattern in at least one surface of the inner layer circuit member and a portion that can be temporarily welded to a peripheral portion in the surface;
A member for an inner layer circuit, wherein a thermal diffusion portion is formed independently of the circuit pattern between the circuit pattern and the portion capable of being temporarily welded.   The inner layer circuit member according to claim 1, wherein the heat diffusion portion is patterned so as to be a continuous body.   The member for an inner layer circuit according to claim 2, wherein the pattern is formed so that the shape of the pattern is missing in a lattice shape or a dot shape. In an inner layer circuit member for a multilayer wiring circuit board obtained by using a laminate in which a prepreg and an inner layer circuit member are laminated and the prepreg is temporarily welded to an adjacent inner layer circuit member,
A circuit pattern in at least one surface of the inner layer circuit member and a temporary welded portion in the peripheral edge portion in the surface,
A method of manufacturing a multilayer wiring circuit board, comprising: using an inner layer circuit member in which a thermal diffusion portion is formed independently of the circuit pattern between the circuit pattern and the temporary welded portion.   The manufacturing method of the multilayer wiring circuit board of Claim 4 whose space | interval between the said thermal diffusion part and the said temporary welding part is 0-10 mm.   6. The method for manufacturing a multilayer wiring circuit board according to claim 4, wherein the width of the heat diffusion portion in the short direction is 4 to 10 times the width in the short direction of the temporarily welded portion. .   The method for manufacturing a multilayer wiring circuit board according to claim 4, wherein the inner layer circuit member is disposed so that the thermal diffusion portion faces the prepreg during the temporary welding.   A multilayer wiring circuit board obtained by using the method for manufacturing a multilayer wiring circuit board according to claim 4.

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