JP5359940B2 - Multilayer circuit board manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a multilayer circuit board in which heat resistance is not deteriorated, and deformation and position shifting of a conductor pattern and formation of a gap at a periphery of the conductor pattern are unlikely to occur. <P>SOLUTION: In the method of manufacturing the multilayer circuit board 100 in which a laminate of resin films made of thermoplastic resin are heated and pressed to be stuck together, the resin films include first resin films 10a and 10b each including a crystalline first base material 10 and having conductor patterns P formed thereupon, and second resin films 30a and 30c each comprising an amorphous second base material 30 whose elastic modulus has a minimum along with crystallization transition, and having no conductor patterns P formed, the second resin films 30a to 30c are laminated and arranged opposite the surfaces of the first resin films 10a and 10b where the conductor patterns P are formed, and the first resin films 10a and 10b and the second resin films 30a to 30c are heated and pressed to be stuck together. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing a multilayer circuit board, in which a laminate of resin films made of a thermoplastic resin is heated and pressed to bond the resin films together.

  A method of manufacturing a multilayer circuit board in which a plurality of resin films each having a conductor pattern made of a metal foil is laminated on one side, and the laminate is heated and pressed to bond the resin films to each other is disclosed in, for example, No. 86948 (Patent Document 1). Moreover, the press construction method at the time of heat-pressing in the manufacturing method of the said multilayer circuit board is disclosed by Unexamined-Japanese-Patent No. 2003-273511 (patent document 2), for example.

  FIGS. 10A and 10B are diagrams for explaining a conventional representative method for manufacturing a multilayer circuit board similar to Patent Document 1, and FIGS. 10A to 10F are cross-sectional views for each manufacturing process of the multilayer circuit board 90. FIGS. It is.

  In the manufacturing method of the multilayer circuit board 90 shown in FIGS. 10A to 10F, first, as shown in FIG. 10A, the resin film 20 of the base material 1 made of a thermoplastic resin is formed by a hot press. A metal (copper) foil 2 is bonded to one side. Next, as shown in FIG. 10B, the copper foil 2 is processed into a predetermined conductor pattern P by etching. Next, as shown in FIG. 10C, a bottomed through hole H having the conductor pattern P as a bottom is formed by laser processing at a predetermined position of the resin film 20. Next, as shown in FIG. 10 (d), the bottomed through hole H is filled with the conductive paste 4. Thereby, the resin film 20 of the base material 1 made of a thermoplastic resin, in which the conductor pattern P is formed on one side and the conductive paste 4 is filled in the bottomed through hole H, can be prepared.

  Next, as shown in FIG. 10E, the resin films 20a to 20f prepared in the same manner as described above are inverted and laminated in the middle as shown in the figure. Finally, the laminated body is heated and pressed by a hot press plate at a temperature just below the melting point of the substrate 1, and the adjacent resin films 20a to 20f are bonded to each other while maintaining the shape of the resin films 20a to 20f. Match. Thereby, as shown in FIG.10 (f), while adjacent resin films 20a-20f of the base material 1 which consists of thermoplastic resins are mutually bonded and integrated, it filled in the through-hole H with a bottom. The conductive paste 4 is sintered to become the connection conductor 4a, and the conductor patterns P of the respective layers are electrically connected.

  Through the above steps, the multilayer circuit board 90 shown in FIG.

  According to the manufacturing method of the multilayer circuit board 90, a plurality of laminated resin films 20a to 20f are bonded together by heating and pressing, and at the same time, the conductive paste 4 is sintered to form the connection conductor 4a. Therefore, the multilayering process can be shortened as compared with a method for manufacturing a multilayer circuit board in which each layer is formed one layer at a time. For this reason, the multilayer circuit board 90 shown in FIG. 10F can be manufactured at low cost.

  Further, in the press method disclosed in Patent Document 2, for example, when a laminated body of resin films 20a to 20f shown in FIG. 10 (e) is heated and pressurized, a resin film 20a on which a hot press plate and a conductor pattern P are formed. A pressing member (buffer material) having a buffering effect is interposed between the laminated bodies of ˜20f. Thereby, the thickness distribution of the laminated body due to the presence of the conductor pattern P can be canceled and a uniform pressure can be applied to the whole. For this reason, the mutual shift | offset | difference etc. of the conductor pattern P currently formed in each resin film 20a-20f can be suppressed, and a product yield can be improved.

JP 2003-86948 A JP 2003-273511 A

  The base material 1 of the resin films 20a to 20f used in the manufacturing method of the multilayer circuit board 90 of FIG. 10 is a thermoplastic resin having high heat resistance, and the multilayer heat press of the resin films 20a to 20f is a base material. It is carried out at a high temperature of 300 ° C. or higher where 1 softens. For this reason, the buffer material disclosed in Patent Document 2 for suppressing the displacement of the conductor pattern P and the like requires heat resistance at a higher temperature and is very expensive, which causes an increase in cost. .

  In recent years, the thickness distribution of the laminate due to the presence of the conductor pattern P tends to increase as the number of laminated resin films increases, and the cushioning material alone covers the thickness distribution and has a uniform pressure throughout. Cannot be applied. For example, in the case of manufacturing a multilayer circuit board by laminating 25 resin films formed with a conductor pattern P using a 12 μm copper foil, a maximum thickness of 12 × 25 = 300 μm at each position of the laminate. Distribution occurs. For this reason, if there is a region in which the conductor pattern P of each layer overlaps greatly in the pressing surface of the laminate, it is not possible to apply the press pressure uniformly with the cushioning material alone. Misalignment occurs, or a gap due to insufficient wraparound of the base material 1 occurs around the conductor pattern P.

  Therefore, the present invention is a method for producing a multilayer circuit board in which a laminate of a resin film made of a thermoplastic resin is heated and pressed to bond the resin films to each other, without deteriorating heat resistance. It is an object of the present invention to provide a method for manufacturing a multilayer circuit board in which deformation or misalignment of a conductor pattern and generation of a gap around the conductor pattern hardly occur.

  Invention of Claim 1 is a manufacturing method of the multilayer circuit board manufactured by heat-pressing the laminated body of the resin film which consists of a thermoplastic resin, and bonding this resin film mutually, Comprising: The said resin film A first resin film comprising a crystalline first base material, on which a conductor pattern made of a metal foil is formed, and a non-crystalline second base material having a minimum in elastic modulus with crystallization transition, It is composed of a second resin film in which a conductive pattern made of metal foil is not formed on the surface, facing the surface on which the conductive pattern of the first resin film is formed, and laminating and arranging the second resin film, The first resin film and the second resin film are bonded to each other by heat and pressure.

  The multilayer circuit board manufacturing method uses two types of resin films. That is, a first resin film made of a crystalline first base material on which a conductor pattern is formed, and a second resin film made of an amorphous second base material on which no conductor pattern is formed. In the said manufacturing method, the 2nd resin film is laminated | stacked and arrange | positioned facing the surface in which the conductor pattern of the 1st resin film was formed, and the 1st resin film and the 2nd resin film are bonded together by heating and pressurization.

  When the laminated body of the first resin film and the second resin film is heated and pressurized, the first resin film made of the crystalline first base material has an elastic modulus of the first base material that gradually decreases as the temperature rises. It gradually softens until reaching the melting point of one substrate. On the other hand, the second resin film made of the amorphous second base material is accompanied by a crystallization transition in the middle of the temperature rise to the melting point of the second base material, and a minimum appears in the elastic modulus of the second base material. That is, when the crystallization transition of the second base material starts in the process of temperature rise during heating and pressurization, the second resin film suddenly decreases in elasticity and softens. After the minimum transition point of the elastic modulus is passed and the crystallization transition is completed and the state is changed to a state having crystallinity, the second base material has an elastic modulus as the temperature rises in the same manner as the crystalline base material. Gradually decreases until it reaches the melting point.

  The manufacturing method of the multilayer circuit board utilizes a difference in elastic modulus change between the first base material and the second base material in a temperature rising process when heating and pressurizing. That is, a conductor pattern is disposed on the surface of a crystalline first base material that gradually softens until reaching the melting point, and this is used as the first resin film to deform or misalign the conductor pattern during the heating process during heating and pressurization. Make it hard to get up. On the other hand, a conductive pattern is not formed on the surface of the non-crystalline second base material in which the minimum elastic modulus appears due to the crystallization transition during the temperature rising to the melting point, and this is used as the second resin film and the first resin film. The conductive pattern is laminated so as to face the surface on which the conductive pattern is formed. When the laminated body of the first resin film and the second resin film is heated and pressed, the first resin film is not softened so much, and the second resin is formed at an early stage during the temperature rise in which the conductor pattern is not easily deformed or displaced. The second substrate of the film can be crystallized and transitioned. At this time, the second base material of the second resin film is in a state where the elastic modulus is rapidly decreased and fluidized easily. As a result, the second base material of the second resin film softened and fluidized while maintaining the initial shape and position of the conductor pattern formed on the first resin film is the conductor pattern of the first resin film. Fill the steps around.

  After the crystallization transition of the second substrate of the second resin film is completed, the lower melting point of the melting point of the first substrate of the first resin film and the melting point of the second substrate of the second resin film is continued. The temperature is raised to just below, and the first resin film and the second resin film are bonded together to manufacture a multilayer circuit board. In the multilayer circuit board manufactured by the above manufacturing method, each part of the insulating base material made of the initial second base material has an irreversible change in crystal state and has crystallinity. For this reason, the multilayer circuit board which consists of a crystalline insulating base material as a whole has high heat resistance. That is, the method for manufacturing a multilayer circuit board utilizes the minimum elastic modulus associated with the crystallization transition of the second base material, and does not employ a base material (resin film) that softens at a low melting point. For this reason, high heat resistance can be ensured in the manufactured multilayer circuit board.

  As described above, the method for manufacturing a multilayer circuit board is a method for manufacturing a multilayer circuit board in which a laminate of resin films made of a thermoplastic resin is heated and pressed and the resin films are bonded to each other. Thus, it is possible to provide a method for manufacturing a multilayer circuit board in which the deformation or misalignment of the conductor pattern and the generation of voids around the conductor pattern do not easily occur without degrading the heat resistance.

  As for the said 1st base material and the said 2nd base material in the manufacturing method of the said multilayer circuit board, as all described in Claim 2, all are polyether ether ketone resin (PEEK), this polyether ether ketone resin, It can be set as the structure which consists of a mixed material of polyetherimide resin (PEI) which makes a completely compatible system.

  The first base material and the second base material made of a mixture of polyether ether ketone resin and polyether imide resin (PEI) are excellent in basic characteristics such as electrical characteristics and chemical resistance, and polyether ether ketone resin and By simply changing the content concentration of the polyetherimide resin, the melting points of the first base material and the second base material can be appropriately set to desired values independently of the crystallinity.

  For example, the content concentration of the polyetherimide resin in the second base material is set to be larger than the content concentration of the polyetherimide resin in the first base material. In this case, the melting point of the second substrate is lower than the melting point of the first substrate.

  For example, as described in claim 4, the content concentration of the polyetherimide resin in the second base material is larger than 70% by weight, and the content concentration of the polyetherimide resin in the first base material is more than 70% by weight. Set it to be small. In this case, the bonding temperature range can be set to around 310 ° C. (about ± 10 ° C.), and the bonding between the first resin film and the second resin film and the connection between the conductor patterns in the bonding temperature range. The conductors can be sintered together.

  In the method of manufacturing a multilayer circuit board, for example, as described in claim 5, the first base material and the second base material can be base materials having the same composition. According to this, since the physical properties such as the coefficient of thermal expansion of the first base material and the second base material are equal after heating and pressing, a multilayer circuit board having a uniform insulating base material can be manufactured.

  In the method for manufacturing a multilayer circuit board, the conductor pattern formed on the first resin film is bonded to the second resin film so as to be an inner conductor pattern of the multilayer circuit board to be manufactured.

  On the other hand, the conductor pattern formed on both side surfaces of the multilayer circuit board may be formed before bonding by heating and pressing with the outermost layer of the laminate as the first resin film. However, as described in claim 6, it is more preferable that an unpatterned metal foil is arranged as the outermost layer of the laminate of the resin films. According to this, the laminate can be heated and pressed more uniformly by the hot press plate. Thereafter, the metal foils on both side surfaces of the multilayer circuit board manufactured by being uniformly pressed are etched into a predetermined conductor pattern.

  As described above, the method for producing a multilayer circuit board is a method for producing a multilayer circuit board in which a laminate of resin films made of a thermoplastic resin is heated and pressed and the resin films are bonded to each other. Thus, it is a method for manufacturing a multilayer circuit board in which the deformation and misalignment of the conductor pattern and the generation of voids around the conductor pattern do not easily occur without deteriorating the heat resistance.

  Therefore, in the manufacturing method of the multilayer circuit board, without using an expensive cushioning material at the time of heating and pressurization, as described in claim 7, for the metal foil disposed in the outermost layer of the laminate. Thus, it is preferable to heat and press the hot press plate directly.

  In the manufacturing method of the multilayer circuit board, for example, as described in claim 8, the first resin film is a double-sided conductor pattern film in which the conductor pattern is formed on both side surfaces of the first base material. There can be a certain configuration. In this case, as described in claim 9, in the second resin film, a through hole in which a conductive material is embedded is formed at a position facing the conductor pattern of the first resin film. It is preferable that According to this, not only the second resin film is used for embedding a step around the conductor pattern formed on the first resin film, but also the connection conductor of the circuit element that connects between the conductor patterns in adjacent layers. It can be used as a retaining layer.

  On the other hand, in the method for producing a multilayer circuit board, as described in claim 10, the first resin film is a single-sided conductor pattern film in which the conductor pattern is formed on one side surface of the first base material. It can also be set as the structure which is. In this case, as described in claim 11, in the second resin film, a through hole is formed at a position facing the conductor pattern of the first resin film with a width smaller than the conductor pattern. It is preferable to become. By appropriately forming the through hole, the second step necessary for embedding the step around the conductor pattern formed in the first resin film at the time of fluidizing the second substrate of the second resin film accompanying the crystallization transition. (2) The amount of movement of the base material can be reduced, so that the deformation and positional deviation of the conductor pattern can be further reduced.

  In the method of manufacturing a multilayer circuit board, for example, as described in claim 12, the first base material and the second base material can be configured to be base materials having the same thickness. According to this, the manufacturing cost of a 1st base material and a 2nd base material can be reduced compared with the case where a 1st base material and a 2nd base material are made into different thickness.

Further, in the method of manufacturing the multilayer circuit board, as claimed in claim 13, the first substrate of the first resin film, Ri name is embedded glass fiber woven fabric, is the first resin film The glass fiber woven fabric was sandwiched between the prepared amorphous second substrates and bonded together by heating and pressing, and the second substrate that was amorphous by slow cooling after heating and pressing. It is also possible to adopt a configuration formed by converting the first base material into crystalline . Also in this case, since the first base material is formed using the second base material, the manufacturing cost of the first base material and the second base material can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of the manufacturing method of the multilayer circuit board based on this invention, (a) is typical sectional drawing which shows the lamination | stacking arrangement | positioning of resin film 10a, 10b, 30a-30c in the middle of manufacture of the multilayer circuit board 100. FIG. 4B is a schematic cross-sectional view of the manufactured multilayer circuit board 100. Temperature rising process for PEEK / PEI = 30/70 (crystalline) and PEEK / PEI = 30/70 (non-crystalline), which are specific examples of the first base material 10 and the second base material 30 in FIG. It is the figure which measured the mode of the change of the dynamic elasticity modulus in. In addition to PEEK / PEI = 30/70 (crystalline) and PEEK / PEI = 30/70 (non-crystalline) in FIG. 2, PEEK / PEI = 20/80 (non-crystalline) and PEEK / PEI = It is the figure which showed the mode of change of the dynamic elastic modulus in the temperature rising process of 40/60 (non-crystal) in comparison. It is a figure which shows an example of the manufacturing method of a 2nd resin film, (a)-(c) is sectional drawing according to a manufacturing process for the 2nd resin film 30a in Fig.1 (a) as an example. It is a figure which shows an example of the manufacturing method of a 1st resin film, (a)-(e) is sectional drawing according to a manufacturing process for the 1st resin film 10b in Fig.1 (a) as an example. It is a figure which shows the manufacture example of another multilayer circuit board, (a) is typical sectional drawing which shows the lamination | stacking arrangement | positioning of resin film 12a, 12b, 30a-30c in the middle of manufacture of the multilayer circuit board 101, (b ) Is a schematic cross-sectional view of the manufactured multilayer circuit board 101. It is a SEM photograph which observed the section of manufactured multilayer circuit board 101 with the electron microscope. (A)-(f) is sectional drawing according to the manufacturing process of the 1st resin film which used the 1st resin film 12b in Fig.6 (a) as an example. It is a figure which shows another example of the manufacturing method which concerns on this invention, (a) is typical sectional drawing which shows the lamination | stacking arrangement | positioning of resin film 20a-20f, 31a-31d in the middle of manufacture of the multilayer circuit board 110, FIG. 4B is a schematic cross-sectional view of the manufactured multilayer circuit board 110. FIG. 8 is a diagram for explaining a conventional representative method for manufacturing a multilayer circuit board similar to Patent Document 1, and FIGS. 9A to 9F are cross-sectional views for each manufacturing process of the multilayer circuit board 90.

  The present invention relates to a method for manufacturing a multilayer circuit board, in which a laminate of resin films made of a thermoplastic resin is heated and pressed to bond the resin films together. Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an example of a method for manufacturing a multilayer circuit board according to the present invention, and FIG. 1 (a) shows a laminated arrangement of resin films 10 a, 10 b, 30 a to 30 c during the manufacturing of the multilayer circuit board 100. FIG. 1B is a schematic cross-sectional view, and FIG. 1B is a schematic cross-sectional view of the manufactured multilayer circuit board 100. In addition, the same code | symbol is attached | subjected about each part of the multilayer circuit board 100 shown in FIG. 1 about the part similar to the multilayer circuit board 90 shown in FIG. FIG. 2 shows PEEK / PEI = 30/70 (crystalline) and PEEK / PEI = 30/70 (non-crystalline), which are specific examples of the first base material 10 and the second base material 30 in FIG. It is the figure which measured the mode of the change of the dynamic elastic modulus in the temperature rising process.

  A multilayer circuit board 100 shown in FIG. 1 heats and pressurizes a laminate of first resin films 10a and 10b and second resin films 30a to 30c made of a thermoplastic resin, so that the first resin films 10a and 10b and second resin films 10a and 10b are second. The resin films 30a to 30c are manufactured by bonding each other.

  As shown to Fig.1 (a), the 1st resin films 10a and 10b consist of the crystalline 1st base material 10, and the conductor pattern P which consists of metal foil is formed in the surface. Note that the first resin films 10 a and 10 b shown in FIG. 1A are double-sided conductor pattern films in which conductor patterns P are formed on both side surfaces of the first base material 10. In addition, through holes in which the conductive material 4b is embedded are formed at predetermined positions on the first base material 10 of the first resin films 10a and 10b, respectively, and both surfaces are formed by sintering the conductive material 4b. The conductor pattern P formed on is electrically connected.

  The 2nd resin films 30a-30c shown to Fig.1 (a) consist of the amorphous 2nd base material 30 from which the minimum appears in an elasticity modulus with a crystallization transition as shown in FIG. Unlike the 1st resin films 10a and 10b, the conductor pattern P which consists of metal foil is not formed in the surface of 2nd resin film 30a-30c. In addition, also in the 2nd resin films 30a-30c shown to Fig.1 (a), the through-hole by which the electrically-conductive material 4b was embedded in the predetermined position facing the conductor pattern P of 1st resin film 10a, 10b is formed. ing.

  As specific examples of the first base material 10 of the first resin films 10a and 10b and the second base material 30 of the second resin films 30a to 30c, all are excellent in basic characteristics such as electrical characteristics and chemical resistance. It has a structure composed of a mixture of polyether ether ketone resin (PEEK) having characteristics and polyether imide resin (PEI) which is completely compatible with the polyether ether ketone resin. Moreover, the said 1st base material 10 and the 2nd base material 30 are good also as a structure from which the same composition differs only in a crystallinity degree. The PEEK / PEI = 30/70 (crystalline) of the first base material 10 and the PEEK / PEI = 30/70 (non-crystalline) of the second base material 30 shown in FIG. 2 are 30% by weight of PEEK / PEI. With the same composition of 70, only the crystallinity is different. That is, PEEK / PEI = 30/70 (crystallinity) of the first base material 10 is crystallized in about 30% of the structure, and PEEK / PEI = 30/70 (non-crystal) of the second base material 30 is The whole structure is amorphous. Due to the difference in crystallinity between the first base material 10 and the second base material 30, even if they have the same composition, as shown in FIG. 2, the crystalline first base material 10 has an elastic modulus as the temperature rises. In contrast to the gradual decrease, the non-crystalline second base material 30 shows a minimum in elastic modulus with the crystallization transition.

  As shown in FIG. 1 (a), the first resin films 10a and 10b made of the first base material 10 and the conductive patterns P are formed and the second resin films 30a to 30c made of the second base material 30. The second resin films 30a to 30c are laminated and disposed so as to face the surface on which the conductor pattern P of the first resin films 10a and 10b is formed. In FIG. 1A, a non-patterned metal foil 2 is disposed as the outermost layer of the laminate of the first resin films 10a and 10b and the second resin films 30a to 30c.

  Next, the laminated body shown in FIG. 1A is heated and pressed with a hot press plate, and the first resin films 10a and 10b and the second resin films 30a to 30c are bonded together. Further, by this heating and pressing, the conductive material 4b shown in FIG. 1A is sintered and changed to the connection conductor 4c, and the conductor patterns P in different layers are electrically connected. At the time of this heating and pressurization, without using an expensive buffer material, a hot press plate is applied to the unpatterned metal foil 2 arranged as the outermost layer of the laminate shown in FIG. Heat and press directly. When the patterned metal foil 2 (conductor pattern P) of the first resin film is disposed on the outermost layer of the laminate, a hot press plate is brought into direct contact with the metal foil 2 and heated. You may press.

  The multilayer circuit board 100 shown in FIG. 1B is manufactured by heating and pressing the laminated body. The multilayer circuit board 100 is completed by etching the metal foil 2 which is the outermost layer of the multilayer circuit board 100 in FIG. 1B into a conductor pattern P having a predetermined shape.

  The manufacturing method of the multilayer circuit board 100 is that two types of resin films are used. That is, the first resin films 10a and 10b composed of the crystalline first base material 10 on which the conductor pattern P is formed, and the second resin film composed of the amorphous second base material 30 on which the conductor pattern P is not formed. 30a-30c. Moreover, in the said manufacturing method, 2nd resin film 30a-30c is laminated and arrange | positioned facing the surface in which the conductor pattern P of 1st resin film 10a, 10b was formed, and the 1st resin film 10a, 10b and the 2nd resin films 30a-30c are bonded together.

  When the laminated body of the first resin films 10a and 10b and the second resin films 30a to 30c shown in FIG. 1A is heated and pressurized, the first resin films 10a and 10b made of the crystalline first base material 10 are: As shown in FIG. 2, the elastic modulus of the first base material 10 gradually decreases as the temperature increases, and gradually becomes soft until the melting point of the first base material 10 is reached. On the other hand, as shown in FIG. 2, the second resin films 30a to 30c made of the non-crystalline second base material 30 have a crystallization transition in the middle of the temperature rise to the melting point of the second base material 30, and the second A minimum appears in the elastic modulus of the substrate 30. That is, when the crystallization transition of the second base material 30 starts in the process of increasing the temperature when the second resin films 30a to 30c are heated and pressurized, the elastic modulus rapidly decreases and softens. After the minimum transition point of the elastic modulus is passed and the crystallization transition is completed and the state is changed to a state having crystallinity, the second base material 30 is accompanied by a temperature rise in the same manner as the crystalline first base material 10. The elastic modulus gradually decreases and gradually becomes soft until reaching the melting point.

  The manufacturing method of the multilayer circuit board 100 shown in FIG. 1 utilizes the difference in elastic modulus change between the first base material 10 and the second base material 30 in the temperature rising process when heating and pressurizing. That is, the conductor pattern P is disposed on the surface of the crystalline first base material 10 that gradually becomes soft until reaching the melting point, and the conductor pattern P is used as the first resin films 10a and 10b in the temperature rising process during heating and pressurization. It is set in a state where it is difficult for P deformation and displacement. On the other hand, the conductive pattern P is not formed on the surface of the non-crystalline second base material 30 in which the minimum of the elastic modulus appears due to the crystallization transition in the middle of the temperature rising to the melting point, and this is used as the second resin films 30a to 30c. The first resin films 10a and 10b are laminated to face the surface on which the conductor pattern P is formed. When the laminated body of the first resin films 10a and 10b and the second resin films 30a to 30c is heated and pressurized, the first resin films 10a and 10b are not softened so much as shown in FIG. The second base material 30 of the second resin films 30a to 30c can be crystallized and transitioned at an early stage in the middle of the temperature rise where the positional deviation is difficult to occur. At this time, the elastic modulus of the second base material 30 of the second resin films 30a to 30c is abruptly decreased, and the second resin film 30a to 30c is easily fluidized. Thereby, the second base film 30 of the second resin films 30a to 30c softened and fluidized while maintaining the initial shape and position of the conductor pattern P formed on the first resin films 10a and 10b, Steps around the conductor pattern P of the first resin films 10a and 10b are filled.

  After the crystallization transition of the second substrate 30 of the second resin films 30a to 30c is completed, the melting point of the first substrate 10 of the first resin films 10a and 10b and the second of the second resin films 30a to 30c are continued. The multilayer circuit board 100 is manufactured by raising the temperature to just below the melting point of the base material 30 and bonding the first resin films 10a and 10b and the second resin films 30a to 30c to each other. In the multilayer circuit board 100 shown in FIG. 1B manufactured by the above manufacturing method, each of the parts 11a to 11c of the base material composed of the initial second base material 30 is irreversibly changed in crystal state. It has sex. For this reason, the multilayer circuit board 100 of FIG.1 (b) which consists of the crystalline base materials 10 and 11a-11c as a whole has high heat resistance. That is, the method of manufacturing the multilayer circuit board 100 uses the minimum elastic modulus accompanying the crystallization transition of the second base material 30 and does not employ a base material (resin film) that softens at a low melting point. Absent. For this reason, in the manufactured multilayer circuit board 100, high heat resistance is securable.

  As described above, the method for manufacturing the multilayer circuit board 100 shown in FIG. 1 heats and presses the laminate of the resin films 10a, 10b, 30a to 30c made of the thermoplastic resin, and the resin films 10a, 10b, 30a. A method for manufacturing a multilayer circuit board in which ˜30c are bonded to each other, in which deformation and misalignment of the conductor pattern P and generation of voids around the conductor pattern P are unlikely to occur without deteriorating heat resistance. This is a circuit board manufacturing method.

  In the method of manufacturing the multilayer circuit board 100 of FIG. 1, the first base material 10 and the second base material 30 are base materials having the same composition that differ only in crystallinity. The first base material 10 and the second base material 30 are not limited to this, and may not have the same composition as long as the crystallinity is different.

  FIG. 3 shows that PEEK / PEI = 30/70 (crystalline) and PEEK / PEI = 30/70 (noncrystalline) in FIG. It is the figure which compared and showed the mode of the change of the dynamic elastic modulus in the temperature rising process of PEEK / PEI = 40/60 (non-crystal).

  The first base material 10 and the second base material 30 made of a mixture of PEEK and PEI are excellent in basic characteristics such as electrical characteristics and chemical resistance, and the first base 10 can be obtained by changing the concentration of PEEK and PEI. The melting points of the material 10 and the second base material 30 can be appropriately set to desired values independently of the crystallinity.

  As the 2nd base material 30 which comprises the 2nd resin films 30a-30c of FIG. 1, PEEK / PEI = 20/80 (non-crystal) and PEEK / PEI = 40/60 (different from melting | fusing point shown in FIG. Amorphous) can be employed, and the bonding temperature with the first resin films 10a and 10b can be appropriately set by selecting these.

  For example, the PEI content concentration in the amorphous second substrate 30 is set to be greater than 70% by weight, and the PEI content concentration in the crystalline first substrate 10 is set to be less than 70% by weight. In this case, the bonding temperature range can be set to around 310 ° C. (about ± 10 ° C.), and the first resin films 10a and 10b and the second resin films 30a to 30c are bonded in the bonding temperature range. In addition, the connection conductors 4b between the conductor patterns P can be sintered together.

  On the other hand, when the first base material 10 and the second base material 30 are base materials having the same composition that differ only in the degree of crystallinity, the physical properties such as the coefficient of thermal expansion of the first base material 10 and the second base material 30 Since it becomes equal after heating and pressing, the multilayer circuit board 100 having a uniform insulating substrate can be manufactured.

  The manufacturing method of the multilayer circuit board 100 shown in FIG. 1 employs a double-sided conductor pattern film in which a conductor pattern P is formed on both side surfaces of the first base material 10 as the first resin films 10a and 10b. The second resin films 30a to 30c in which the conductive material 4b is embedded in 30 are employed. According to this configuration, the second resin films 30a to 30c are not only used for embedding a step around the conductor pattern P formed in the first resin films 10a and 10b, but also the conductor pattern P in an adjacent layer. It can be used as a holding layer for connection conductors of circuit elements that connect each other.

  Moreover, in the manufacturing method of the multilayer circuit board 100 shown in FIG. 1, since the conductor pattern P formed in the first resin films 10a and 10b is bonded to face the second resin films 30a to 30c, it is manufactured. The conductive pattern P is the inner layer of the multilayer circuit board 100. In the manufacturing method of the multilayer circuit board 100 of FIG. 1, it was set as the structure by which the unpatterned metal foil 2 was arrange | positioned as the outermost layer of the laminated body of resin film 10a, 10b, 30a-30c. According to this, the laminate can be heated and pressed more uniformly by the hot press plate. After that, the metal foil 2 on both surfaces of the multilayer circuit board 100 manufactured by being uniformly pressed was etched into a predetermined conductor pattern P. However, not limited to this manufacturing method, the outermost layer of the laminate is formed as a first resin film having a conductor pattern, and a conductor pattern to be formed on both surfaces of the multilayer circuit board is formed in advance before bonding by heating and pressing. You may make it leave.

  Next, a preferable method for manufacturing the second resin films 30a to 30c and the first resin films 10a and 10b used for manufacturing the multilayer circuit board 100 of FIG. 1 will be described.

  FIG. 4 is a diagram illustrating an example of a method for manufacturing the second resin film, and FIGS. 4A to 4C are diagrams illustrating the second resin film 30a in FIG. It is sectional drawing.

  First, an amorphous second base material 30 shown in FIG. 4A is prepared. Next, as shown in FIG.4 (b), the through-hole H is formed in the 2nd base material 30 by laser processing. Finally, as shown in FIG. 4C, the through hole H is filled with a conductive material 4b. Note that, unlike the conductive paste 4 shown in FIG. 10, the conductive material 4b filled in the through hole H of the second base material 30 is preferably a conductive material that melts at a predetermined temperature higher than room temperature. For example, the conductive material 4b made of a mixture of a metal filler and a low melting point solid dispersant such as paraffin (melted at a low temperature in a solid state at room temperature) is used to fill the through hole H of the second base material 30 while heating. To do. If the 2nd base material 30 is cooled after filling, since the electrically-conductive material 4b will solidify, handling of the 2nd resin film 30a will become easy.

  Thus, the amorphous second resin film 30a can be manufactured.

  FIG. 5 is a diagram illustrating an example of a manufacturing method of the first resin film, and FIGS. 5A to 5E show the first resin film 10b in FIG. It is sectional drawing.

  First, as shown in FIGS. 5A to 5C, an amorphous second base material 30 similar to that shown in FIG. 4A is prepared, and the same as FIGS. 4B and 4C. Then, the through hole H is formed in the second base material 30, and the conductive material 4b is filled in the through hole H. Next, as shown in FIG.5 (d), the metal foil 2 is arrange | positioned and laminated | stacked on both sides of the 2nd base material 30 of FIG.5 (c), it heat-presses with a hot press board, and these are bonded together. . After the heating and pressurization, the second base material 30 that has been amorphous is changed to the crystalline first base material 10 by slowly cooling. Finally, as shown in FIG. 5E, the metal foil 2 is etched to form a conductor pattern P.

  Thus, the crystalline first resin film 10b can be manufactured.

  As can be seen from the manufacturing method of the first resin film 10b shown in FIG. 5 and the manufacturing method of the second resin film 30a shown in FIG. 4, the first resin used in the manufacturing method of the multilayer circuit board 100 of FIG. The first base material 10 of the films 10a and 10b and the second base material 30 of the second resin films 30a to 30c are manufactured from the same second base material 30, and are base materials having the same thickness. According to this, since the same 2nd base material 30 can be used as a starting material compared with the case where the 1st base material 10 and the 2nd base material 30 are made into different thickness, the 1st base material 10 and the 2nd The manufacturing cost of the base material 30 can be reduced.

  FIG. 6 is a view showing another example of manufacturing a multilayer circuit board, and FIG. 6A is a schematic cross-sectional view showing a laminated arrangement of the resin films 12a, 12b, 30a to 30c in the process of manufacturing the multilayer circuit board 101. FIG. 6B is a schematic cross-sectional view of the manufactured multilayer circuit board 101. In addition, about the same part as the multilayer circuit board 100 shown in FIG. 1, about the part of the multilayer circuit board 101 shown in FIG. 6, the same code | symbol was attached | subjected. FIG. 7 is an SEM photograph in which a cross section of the manufactured multilayer circuit board 101 is observed with an electron microscope. FIGS. 8A to 8F are cross-sectional views of the first resin film according to the manufacturing process, taking the first resin film 12b in FIG. 6A as an example.

  The manufacturing method of the multilayer circuit board 101 shown in FIG. 6 differs from the manufacturing method of the multilayer circuit board 100 shown in FIG. 1 only in that the first resin films 12a and 12b are used. The first resin films 12a and 12b shown in FIG. 6 are made of a crystalline first base material 12 made of a thermoplastic resin, like the first resin films 10a and 10b of FIG. A pattern P is formed. Further, a glass fiber woven fabric G is embedded in the first base material 12. A multilayer circuit board 101 shown in FIG. 6 heats and pressurizes a laminate composed of the first resin films 12a and 12b and the amorphous second resin films 30a to 30c similar to FIG. , 12b and the second resin films 30a to 30c are bonded together. Therefore, the multilayer circuit board 101 shown in FIG. 6 is also highly heat resistant, deforms and misaligns the conductor pattern P, and generates voids around the conductor pattern P in the same manner as the multilayer circuit board 100 shown in FIG. Needless to say, it can be manufactured with restraint.

  As shown in FIG. 7, there is no deformation or misalignment of the conductor pattern P, the non-crystalline second base material 30 is fluidized in the course of manufacturing, and the crystallized base material 11 b enters around the conductor pattern P, resulting in voids. Is prevented.

  As for the production of the first resin film 12b in which the glass fiber woven fabric G shown in FIG. 6 is embedded, first, as shown in FIG. The fiber woven fabric G is sandwiched and laminated between the second base materials 30. Next, the laminate is bonded by heating and pressing with a hot press plate. After this heating and pressurization, by slowly cooling, the first base material in which the second base material 30 that is amorphous is crystalline and the glass fiber woven fabric G is embedded as shown in FIG. Change to 12. In the subsequent steps, as shown in FIG. 8C, a through hole H is formed in the first substrate 12, and as shown in FIG. 8D, the through hole H is filled with a conductive material 4b. Next, as shown in FIG. 8 (e), the metal foil 2 is bonded to both sides of the first substrate 12, and finally the metal foil 2 is etched as shown in FIG. 8 (f). A conductor pattern P is formed.

  With the above, the first resin film 12b that is crystalline and in which the glass fiber woven fabric G is embedded can be manufactured.

  In the manufacturing method of the first resin film 12b shown in FIG. 8 described above, the first base material 12 is formed using the same second base material 30, and the manufacturing cost of the first base material 12 is reduced. Can do. Therefore, also in the manufacture of the multilayer circuit board 101 shown in FIG. 6, the manufacturing cost of the first base material 12 and the second base material 30 can be reduced.

  FIG. 9 is a diagram illustrating another example of the manufacturing method according to the present invention, and FIG. 9A is a schematic diagram illustrating a laminated arrangement of the resin films 20a to 20f and 31a to 31d during the manufacturing of the multilayer circuit board 110. FIG. 9B is a schematic cross-sectional view of the manufactured multilayer circuit board 110. In addition, about each part of the multilayer circuit board 110 shown in FIG. 9, the same code | symbol was attached | subjected about the part similar to the multilayer circuit board 90 shown in FIG.

  In the method of manufacturing the multilayer circuit board 110 shown in FIG. 9, the resin films 20a to 20f used for manufacturing the multilayer circuit board 90 of FIG. 10 are used as the first resin film. The first resin films 20a to 20f are single-sided conductor pattern films in which a conductor pattern P is formed on one side surface of a crystalline first base material 1 made of a thermoplastic resin. Amorphous second resin films 31a to 31d made of a thermoplastic resin are used together with the first resin films 20a to 20f. Although the conductor pattern P is not formed on the surface of the second base material 31 of the second resin films 31a to 31d, the conductor pattern P1 of the first resin films 20a to 20f is shown in the stacked arrangement of FIG. A through hole H1 having a smaller width than the conductor pattern P1 is formed at a position opposite to.

  The first resin films 20a to 20f and the second resin films 31a to 31d are laminated as shown in FIG. 9 (a), and the laminated body is heated and pressurized to form the first resin films 20a to 20f and the second resin film. 31a to 31d are bonded together. As a result, the second base material 31 of the second resin films 31a to 31d is fluidized at the time of crystallization transition in the middle of the temperature rise, and becomes the base material 13 that is embedded around the conductor pattern P to be crystallized, and FIG. The multilayer circuit board 110 shown in FIG. The multilayer circuit board 110 shown in FIG. 9 also has high heat resistance and suppresses the deformation and misalignment of the conductor pattern P and the generation of voids around the conductor pattern P in the same manner as the multilayer circuit board 100 shown in FIG. Needless to say, it can be manufactured.

  In particular, in the method of manufacturing the multilayer circuit board 110 shown in FIG. 9, the second base material of the second resin films 31a to 31d accompanying the crystallization transition is formed by appropriately forming the through holes H1 in the second resin films 31a to 31d. At the time of fluidizing 31, the amount of movement of the second substrate 31 necessary for embedding the steps around the conductor pattern P1 formed on the first resin films 20a to 20f is reduced, and the deformation and position of the conductor pattern P1 are reduced. The deviation can be further reduced.

  As described above, in any of the above-described multilayer circuit board manufacturing methods, a multilayer circuit board is manufactured by heating and pressing a laminate of resin films made of a thermoplastic resin and bonding the resin films to each other. This method is a method for manufacturing a multilayer circuit board in which the deformation and misalignment of the conductor pattern and the generation of voids around the conductor pattern do not easily occur without deteriorating the heat resistance.

100, 101, 110 Multilayer circuit board 10a, 10b, 12a, 12b, 20a-20f 1st resin film 10, 12 1st base material P, P1 Conductive pattern 30a-30c, 31a-31d 2nd resin film 30, 31 1st 2 Substrate H, H1 Through hole 4b Conductive material 2 Metal foil

Claims (13)

A method for producing a multilayer circuit board, in which a laminate of a resin film made of a thermoplastic resin is heated and pressurized and the resin films are bonded together,
The resin film is
A first resin film made of a crystalline first base material and having a conductive pattern made of a metal foil on the surface;
It consists of a non-crystalline second base material in which a minimum in elastic modulus appears along with the crystallization transition, and a second resin film in which a conductor pattern made of a metal foil is not formed on the surface,
The second resin film is laminated and disposed so as to face the surface on which the conductive pattern of the first resin film is formed,
A method for producing a multilayer circuit board, wherein the first resin film and the second resin film are bonded to each other by heat and pressure.   Each of the first base material and the second base material is composed of a mixture of a polyether ether ketone resin (PEEK) and a polyether imide resin (PEI) that is completely compatible with the polyether ether ketone resin. The method of manufacturing a multilayer circuit board according to claim 1.   The method for producing a multilayer circuit board according to claim 2, wherein the content concentration of the polyetherimide resin in the second base material is higher than the content concentration of the polyetherimide resin in the first base material. The content of the polyetherimide resin in the second substrate is greater than 70% by weight,
The method for producing a multilayer circuit board according to claim 3, wherein the content of the polyetherimide resin in the first base material is less than 70% by weight.   The method for manufacturing a multilayer circuit board according to claim 1, wherein the first base material and the second base material are base materials having the same composition.   6. The method for producing a multilayer circuit board according to claim 1, wherein an unpatterned metal foil is disposed as an outermost layer of the laminate of the resin films.   The multilayer circuit board according to any one of claims 1 to 6, wherein the metal foil disposed in the outermost layer of the laminate is heated and pressed by directly contacting a hot press plate. Production method. The first resin film is
The method for manufacturing a multilayer circuit board according to any one of claims 1 to 7, wherein the conductive pattern film is a double-sided conductor pattern film in which the conductor pattern is formed on both side surfaces of the first base material. In the second resin film,
The method for manufacturing a multilayer circuit board according to claim 8, wherein a through hole in which a conductive material is embedded is formed at a position of the first resin film facing the conductor pattern. The first resin film is
The method for producing a multilayer circuit board according to any one of claims 1 to 7, which is a single-sided conductor pattern film in which the conductor pattern is formed on one side surface of the first base material. In the second resin film,
The method for manufacturing a multilayer circuit board according to claim 10, wherein a through hole is formed at a position facing the conductor pattern of the first resin film with a width smaller than the conductor pattern.   The method for manufacturing a multilayer circuit board according to any one of claims 1 to 11, wherein the first base material and the second base material are base materials having the same thickness. The first substrate of the first resin film, Ri name is embedded glass fiber woven fabric,
The first resin film is sandwiched between the amorphous second substrates prepared with the glass fiber woven fabric and bonded together by heating and pressing, and the first resin film is amorphous by gradual cooling after heating and pressing. 2. The method of manufacturing a multilayer circuit board according to claim 1 , wherein the second base material is formed by converting the second base material into the crystalline first base material .