JP3867526B2 - Multilayer substrate manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a multilayer substrate, and in particular, a plurality of resin films including a conductor pattern film on which a conductor pattern is formed are laminated, and the laminated resin film is heated and pressurized to form a multilayer substrate. The present invention relates to a method for manufacturing a multilayer substrate.
[0002]
[Prior art]
Conventionally, as a method of manufacturing a multilayer substrate, a resin film including a conductor pattern film on which a conductor pattern is formed is laminated, and a plurality of resin films are bonded together by heating and pressing them to manufacture a multilayer substrate. How to do is known.
[0003]
For example, according to the method for manufacturing a multilayer substrate disclosed in Japanese Patent Application Laid-Open No. 2000-38464, first, a conductor pattern is formed on both surfaces of a resin film made of a thermoplastic resin, and the conductor patterns on both surfaces are interlayered with a conductive paste. A plurality of connected double-sided conductor pattern films are produced. Next, the plurality of double-sided conductor pattern films are laminated via a resin film that has been processed to allow interlayer connection. Then, the laminated double-sided conductor pattern film and resin film are pressurized at a predetermined pressure while being heated to a predetermined temperature. Thereby, the thermoplastic resin which comprises a resin film is softened and it adheres. In this heating / pressurizing step, for example, a current is passed through a press plate made of a conductive metal material such as titanium to generate heat, and the generated press plate is pressed against the laminated resin film. This is performed by applying a predetermined pressure.
[0004]
[Problems to be solved by the invention]
In a multilayer substrate, it is necessary to connect the conductor patterns formed in each layer to each other. This interlayer connection is usually made by forming a via hole in a resin film and using an interlayer connection material filled in the via hole. Therefore, if the positions of the via hole filled with the interlayer connection material and the conductor pattern are shifted when laminating the resin film, the resin film cannot be used as a circuit. It must be accurately positioned and stacked.
[0005]
For this reason, each resin film is laminated | stacked, image-recognizing the position of the conductor pattern of each resin film, or the position of a via hole, and aligning in the position which those match.
[0006]
The resin films laminated while aligning are bonded to each other by a heating / pressurizing process to form a multilayer substrate. Usually, the equipment for performing the aligning process is different from the equipment for performing the heating / pressurizing process. For this reason, the resin film positioned and laminated with high accuracy may cause a positional shift when it is transferred to a facility for performing a heating / pressurizing process.
[0007]
The present invention has been made in view of the above points, and provides a method for manufacturing a multilayer substrate that prevents misalignment of the laminated resin films and that can reliably connect the conductive patterns of each layer of the multilayer substrate. Objective.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a method for manufacturing a multilayer substrate according to claim 1 comprises:
Preparing a conductive pattern film in which a conductive pattern is formed on at least one side of a resin film made of a thermoplastic resin ;
While positioning the resin film containing the conductive pattern film, a step of plurally stacked,
Temporarily fixing the plurality of resin films by temporarily melting at least a part of the laminated resin films, and temporarily fixing the plurality of resin films ;
A method of manufacturing a multilayer substrate comprising: a heating / pressurizing step of bonding the resin films to each other to form a multilayer substrate by pressing the temporarily fixed resin film while being heated by a hot press plate. ,
In the temporary fixing step, at least a part of the laminated resin film is heated and melted,
An annular conductor pattern is provided at least on the resin film located on the outermost surface so as to surround the periphery of the position where the resin film is heated and melted,
The temporary fixing step is performed around the heating member of all the resin films laminated so that the tip of the heated heating member reaches the lowermost resin film from the annular conductor pattern of the resin film located on the outermost surface. It is characterized by melting the resin .
[0009]
That is, the manufacturing method of the multilayer substrate according to claim 1 pays attention to the fact that the insulator constituting the multilayer substrate is a thermoplastic resin, and after positioning and laminating the resin film, before performing the heating / pressing step. The resin film is temporarily fixed until a necessary part of the laminated thermoplastic resin is heated and melted at the tip of a heated heating member to reach the lowermost resin film . Thereby, since the laminated | stacked resin film can be temporarily fixed reliably and reliably, when transferring to the installation which performs a heating / pressurizing process, it can prevent that a resin film shifts. Therefore, it is possible to prevent problems such as non-conduction of circuits in the multilayer substrate and improve the production yield of the multilayer substrate.
[0010]
According to a second aspect of the present invention, in the temporary fixing step, a hole is formed in the resin film by a tip of the heating member, and the hole of the resin film is surrounded by the heating / pressurizing step. The strength can be increased by flowing the thermoplastic resin .
[0011]
A step of preparing a conductor pattern film in which a conductor pattern is formed on at least one surface of a resin film made of a thermoplastic resin as described in claim 3 ;
While positioning the resin film including the conductor pattern film, a step of laminating a plurality of sheets,
Temporarily fixing the plurality of resin films by temporarily melting at least a part of the laminated resin films, and temporarily fixing the plurality of resin films;
A method of manufacturing a multilayer substrate comprising: a heating / pressurizing step of bonding the resin films to each other to form a multilayer substrate by pressing the temporarily fixed resin film while being heated by a hot press plate. ,
In the temporary fixing step, after laminating all the number of resin films to be laminated, at least a part of the total number of resin films is heated and melted to temporarily fix all the number of resin films to be laminated. Done
An annular conductor pattern is provided on the resin film located at least on the outermost surface so as to surround the periphery of the position where the resin film is heated and melted,
In the temporary fixing step, the pressure was applied by applying pressure to the annular conductor pattern of the resin film in which the tip of the heated heating member is located on the outermost surface in the pressing direction of the heating / pressurizing step. The conductive pattern is deformed so that a part of the conductive pattern bites into the resin film below .
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0022]
(First embodiment)
FIG. 1 is a cross-sectional view for each process showing the manufacturing process of the multilayer substrate in the present embodiment.
[0023]
First, as shown to Fig.1 (a), the conductor foil 20 (this example 18-micrometer-thick copper foil) is affixed on the single side | surface of the resin film 23 which consists of thermoplastic resins. Next, in FIG.1 (b), the conductor foil 20 stuck on the single side | surface of the resin film 23 is patterned by an etching, and the conductor pattern 22 is formed. In this way, the single-sided conductor pattern film 21 having the conductor pattern 22 on one side is formed. In this example, a resin film having a thickness of 25 to 75 μm composed of 65 to 35% by weight of polyetheretherketone (PEEK) resin and 35 to 65% by weight of polyetherimide (PEI) resin is used as the resin film 23. Moreover, as conductor foil, other metal foils, such as aluminum foil, can also be used besides copper foil. The conductor pattern 22a is formed so as to surround the periphery of the portion heated to temporarily fix the resin film 23. The temporary fixing of the resin film 23 will be described in detail later.
[0024]
As shown in FIG. 1B, when the formation of the conductor patterns 22 and 22a is completed, the conductor pattern 22 is then irradiated by irradiating a carbon dioxide laser from the resin film 23 side as shown in FIG. A via hole 24 that is a bottomed via hole serving as a bottom surface is formed. The via hole is formed by adjusting the output of the carbon dioxide laser and the irradiation time so as not to make a hole in the conductor pattern 22.
[0025]
For the formation of the via hole 24, an excimer laser or the like can be used in addition to the carbon dioxide laser. A via hole forming method such as drilling other than laser is also possible, but drilling with a laser beam is preferable because it can be made with a fine diameter and damage to the conductor pattern 22 is small.
[0026]
When the formation of the via hole 24 is completed as shown in FIG. 1C, next, as shown in FIG. 1D, the via hole 24 is filled with a conductive paste 50 that is an interlayer connection material. The conductive paste 50 is obtained by adding a binder resin or an organic solvent to metal particles such as copper, silver, and tin and kneading them to form a paste.
[0027]
The conductive paste 50 is printed and filled in the via hole 24 by a screen printer using a metal mask. Further, in this example, the screen paste is used for filling the conductive paste 50 into the via hole 24. However, another method using a dispenser or the like may be used as long as the filling can be performed reliably.
[0028]
When the filling of the conductive paste 50 into the via hole 24 is completed, a plurality of (6 in this example) single-sided conductor pattern films 21 are laminated as shown in FIG. At this time, the lower three single-sided conductor pattern films 21 have the side on which the conductor pattern 22 is provided as the lower side, and the upper three single-sided conductor pattern films 21 have the side on which the conductor pattern 22 is provided. Laminate as the upper side.
[0029]
That is, the two single-sided conductor pattern films 21 in the center are laminated so that the surfaces on which the conductor pattern 22 is not formed face each other, and on both sides, the surface on which the conductor pattern 22 is formed and the conductor pattern 22 are formed. Two single-sided conductor pattern films 21 are laminated so that the opposite surfaces face each other.
[0030]
As described above, in the present embodiment, the multilayer substrate 100 is configured using the single-sided conductor pattern film 21 in which the conductor pattern 22 is formed only on one side. For this reason, since the film which comprises a multilayer substrate can be formed only by the process and equipment which manufacture the single-sided conductor pattern film 21, it is effective in the simplification of manufacturing equipment and reduction of manufacturing cost.
[0031]
In the present embodiment, the two single-sided conductor pattern films 21 at the center are laminated so that the surfaces on which the conductor pattern 22 is not formed face each other, and the remaining one-sided conductor pattern film 21 has the conductor pattern 22 formed thereon. The laminated surface and the surface on which the conductor pattern 22 is not formed are laminated so as to face each other. For this reason, the electrode by the conductor pattern 22 can be formed in both surfaces of a multilayer substrate, using the single-sided conductor pattern film 21. FIG. Thereby, since electrodes for connecting to electronic components and external circuits can be formed on both surfaces of the multilayer substrate, high-density mounting or downsizing of the multilayer substrate can be achieved.
[0032]
As described above, when laminating the single-sided conductor pattern film 21, it is necessary to align the conductor pattern 22 formed in each layer of the multilayer substrate 100 and the via hole 24 filled with the interlayer connection material. The positions of the conductor patterns 22 and via holes 24 are recognized by image processing and positioned at a desired position with respect to the lower-layer single-sided conductor pattern film 21 and then laminated. For this positioning, in addition to image processing, a means may be employed in which positioning holes are formed in a plurality of locations in each single-sided conductor pattern film 21 and these holes are inserted into a common support rod.
[0033]
When the single-sided conductor pattern film 21 is laminated as shown in FIG. 1 (e), a temporary fixing step of the single-sided conductor pattern film 21 is performed as shown in FIG. 1 (f). In this temporary fixing process, a part of all the laminated resin films 23 is heated and melted by a heating member 60 such as a trowel having a small tip. The heating position 25 of the resin film 23 is an area surrounded by the conductor pattern 22a.
[0034]
Since the melting temperature of the resin film 23 composed of PEEK and PEI is about 350 ° C., the heating temperature by the heating member 60 is set to be equal to or higher than the melting temperature, for example, a temperature in the range of 360 ° C. to 400 ° C. The In a state where the heating member 60 is heated to this heating temperature, the heating member 60 is pressed so that the tip of the heating member 60 reaches the lowermost resin film 23 of the laminated resin film 23. Thereby, since the resin around the heating member 60 of all the resin films 23 is melted, the resin films 23 laminated by the melted resin are bonded to each other.
[0035]
As described above, the conductor pattern 22a is formed around the position where the heating member 60 is pressed. By this conductor pattern 22a, the heat applied to each resin film 23 from the heating member 60 is radiated through the conductor pattern 22a. For this reason, the melting range of the resin is limited to a region surrounded by the conductor pattern 22a, and the influence of heating on the resin film 23 outside the region can be prevented.
[0036]
In the example shown in FIG. 1 (f), the conductor pattern 22a is formed on each resin film 23 to be laminated. In this case, the heat applied to melt the resin of each layer is transmitted to the conductor pattern 22a of each layer, and is further radiated from the conductor pattern 22a exposed on the surface. Therefore, by forming the conductor pattern 22a on each resin film 23, the heat applied to the resin of each layer is efficiently radiated. However, since the thickness of each resin film 23 and the conductor pattern 22a is thin, if a conductor pattern 22a for heat dissipation is provided at least on the resin film 23 located on the surface, the resin in the region outside the conductor pattern 22a, The influence of heating can be prevented.
[0037]
When the resin is heated in each region surrounded by the conductor pattern 22a and the entire resin film 23 is melt-bonded, the temporarily fixed single-sided conductor pattern film 21 is heated from both the upper and lower surfaces by a heating press machine (not shown). Pressurized. Illustrating specific heating and pressurizing conditions, the pressure is a value in the range of 0.1 to 10 MPa, and the heating temperature is a value in the range of 200 to 350 ° C. Furthermore, the heating / pressurizing time is set to about 10 to 40 minutes.
[0038]
As shown in FIG. 1 (g), the thermoplastic resin constituting each single-sided conductor pattern film 21 is brought into close contact with the softened state by the heating / pressurizing process described above, so that they are bonded to each other. That is, the resin film 23 is heat-sealed and integrated, and adjacent conductive patterns 22 are connected to each other by the conductive paste 50 in the via hole 24, so that the multilayer substrate 100 having the electrodes 32 and 37 on both sides is obtained. .
[0039]
In addition, when a part of the resin film 23 is melted in the temporary fixing process, a hole is made in each resin film 23. However, since the resin around the hole flows by the heating and pressurizing process, the hole is , Filled with inflowing resin.
[0040]
In FIG. 2, the perspective view of the single-sided conductor pattern film 21 laminated | stacked is shown. 2 shows a perspective view of three single-sided conductor pattern films 21 on the upper side of the multilayer substrate 100 shown in FIG. 1 for convenience.
[0041]
In FIG. 2, reference numeral 70 denotes a region that is cut out as a product after the multilayer substrate 100 is formed. Two product regions 70 are set in the single-sided conductor pattern film 21. A substantially quadrangular annular conductor pattern 22 a is formed on each single-sided conductor pattern film 21 so as to surround the two product regions 70. A plurality of holes are provided in each side of the quadrangular annular conductor pattern 22 a, and these holes serve as heating and melting positions 25.
[0042]
That is, the heating member 60 is pressed against the holes provided in the respective sides of the quadrangular annular conductor pattern 22a, and the resin of all the laminated resin films 23 is melted and temporarily fixed. At this time, at least two hole portions provided on two sides, more preferably, four hole portions provided on four sides are set as the heating and melting position 25. Thereby, the position shift (position shift to the front and rear, right and left, and a rotation direction) of the single-sided conductor pattern film 21 can be prevented reliably.
[0043]
In addition, when temporary fixing is performed, every time the single-sided conductor pattern films 21 are positioned and stacked, together with the lower-side single-sided conductor pattern film 21, a part of the resin film 23 may be heated and melted to temporarily fix. good. If it does in this way, it can be surely temporarily fixed to a desired position, maintaining the positioning accuracy of each single-sided conductor pattern film 21.
[0044]
However, if a part of the resin film 23 is heated and melted by the heating member 60, a hole is formed in the resin film 23. For this reason, when each conductor pattern film 21 is positioned and stacked, when a part of the resin film 23 is heated and melted and temporarily fixed, the resin film 23 is changed at a different position each time the single-sided conductor pattern film 21 is stacked. It is preferable to perform heating and melting. That is, a plurality of holes are provided on each side of the conductor pattern 22a shown in FIG. 2, and the hole as the melting position 25 is shifted each time the single-sided conductor pattern 21 is laminated one by one. . Thereby, the resin to be melted can be secured, and temporary fixing can be surely performed for each single-sided conductor pattern film.
[0045]
(Second Embodiment)
Next, a second embodiment of the present invention will be described.
[0046]
Note that the description of the structure of the multilayer substrate similar to that of the first embodiment and the same manufacturing process will be omitted, and the structure and processes unique to the second embodiment will be described.
[0047]
In the present embodiment, heating members 70a and 70b such as heaters are brought into contact with conductor patterns 26a and 26b formed on the single-sided conductor pattern film 21 located on the outermost surface of the multilayer substrate, and the outermost conductor patterns 26a and 26b It is characterized in that temporary fixing is performed by applying heat and pressure to the thermoplastic resin below it through 26b. Details will be described below.
[0048]
After the single-sided conductor pattern film 21 is formed in the same manner as in the first embodiment described above, it is laminated as shown in FIG. At this time, on each resin film 23, a conductor pattern 22 for forming an electric circuit in the multilayer substrate and conductor patterns 26a and 26b used for temporary fixing are formed. The conductor patterns 26a and 26b are formed in an annular shape so as to surround an adhesion region where the single-sided conductor pattern films 21 laminated to constitute a multilayer substrate are adhered to each other. That is, the conductor patterns 26a and 26b in FIG. 3A each represent a part of a continuous annular conductor pattern.
[0049]
When the single-sided conductor pattern film 21 is laminated as shown in FIG. 3 (a), the single-sided conductor pattern film 21 is temporarily fixed as shown in FIG. 3 (b). In this temporary fixing step, pressure is applied in the compressing direction of the multilayer substrate over the entire circumference of the conductor patterns 26a and 26b by the heating members 70a and 70b having the annular ends formed in the same shape as the conductor patterns 26a and 26b. Meanwhile, the thermoplastic resin constituting each resin film 23 is heated to the melting temperature or higher. Note that the tip end area of the heating members 70a and 70b, that is, the area in contact with the conductor patterns 26a and 26b is smaller than the area of the conductor patterns 26a and 26b, and the heating members 70a and 70b are in the width direction of the conductor patterns 26a and 26b. It touches only the center part of the.
[0050]
By such a temporary fixing step, as shown in FIG. 3C, the central portions of the conductor patterns 26a and 26b are deformed so as to be difficult to insert into the lower resin film 23, and the resin film 23 of each layer is configured. The thermoplastic resin is also melted by heating. Since the molten thermoplastic resin adheres to the conductor patterns 26a and 26b or the thermoplastic resin of the adjacent resin film 23, the laminated single-sided conductor pattern films 21 are temporarily fixed.
[0051]
Here, once the thermoplastic resin constituting each resin film 23 is melted, the heating and melting temperature for melting again tends to increase. Furthermore, when the conductor patterns 26a and 26b are provided so as to surround the adhesion area of the multilayer substrate and heat and pressure are applied over the entire circumference, the conductor patterns 26a and 26b are deformed so as to be difficult to insert into the lower resin film 23. Is done. For this reason, in the multilayer substrate forming process after the temporary fixing process, even if the laminated single-sided conductor pattern film 21 is pressed while being heated by a hot press plate, the annular conductor patterns 26a and 26b and the lower layers thereof are melted. Since the four sides are surrounded by the resin, excessive deformation of the thermoplastic resin in the adhesion region is suppressed. Accordingly, it is possible to effectively prevent the positional deviation between the layers of the multilayer substrate, the positional deviation between the resin film 23 and the conductive pattern 22 in the single-sided conductive pattern film 21, the disconnection of the conductive pattern 22, and the like.
[0052]
Also in this embodiment, as in the first embodiment described above, the conductor patterns 26a and 26b used in the temporary fixing process are set outside the region to be a product, and after the multilayer substrate is formed, the product It may be separated from the part.
[0053]
Moreover, in 2nd Embodiment mentioned above, although conductor pattern 26a, 26b was provided in each single-sided conductor pattern film 21, conductor pattern 26a, 26b is on at least the single-sided conductor pattern film 21 of the outermost surface for heat dissipation. The conductor patterns 26a and 26b may not be provided on each resin film 23 corresponding to the inner layer.
[0054]
Furthermore, in the above-described second embodiment, the conductor patterns 26a and 26b are formed as a continuous annular pattern, but a plurality of separated conductor patterns are intermittently arranged so as to be annular as a whole, and the conductor pattern is Only the existing part may be pressed and heated by the heating member. Further, at least a part of the annular conductor patterns 26a and 26b may be pressurized and heated by the heating members 70a and 70b, not the entire circumference. Even in this case, the purpose of temporary fixing can be sufficiently achieved by the thermoplastic resin melted by the heating members 70a and 70b.
[0055]
(Other embodiments)
In the first embodiment, the electrodes 32 and 37 are taken out from both surfaces of the multilayer substrate 100 by using only the single-sided conductor pattern film 21 and bonding the surfaces on which the conductor pattern 22 is not formed on the two central sheets. .
[0056]
However, the configuration of the multilayer substrate is not limited to the first embodiment. For example, all the single-sided conductor pattern films may be laminated in the same direction, and the electrodes may be taken out only from one side. Moreover, you may comprise a multilayer substrate using the double-sided conductor pattern film which formed the conductor pattern on both surfaces of the resin film. For example, a plurality of double-sided conductor pattern films may be prepared, and they may be laminated via a film in which an interlayer connection material is filled in via holes, or a single-sided conductor pattern film on each side of a single double-sided conductor pattern film. May be laminated.
[0057]
Moreover, in the said 1st Embodiment, although the resin film which consists of 65-35 weight% of polyetheretherketone resin and 35-65 weight% of polyetherimide resin was used as the resin film 23, it is not restricted to this. A film in which a filler is filled in an ether ether ketone resin and a polyether imide resin may be used, or polyether ether ketone (PEEK) or polyether imide (PEI) may be used alone.
[0058]
Furthermore, as the resin film, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyethersulfone (PES), thermoplastic polyimide, or a so-called liquid crystal polymer may be used. Or you may use the thing of the structure which laminated | stacked the layer which consists of a thermoplastic resin of at least any one of PEEK, PEI, PEN, PET, PES, a thermoplastic polyimide, and a liquid crystal polymer on the polyimide film. Any resin film that can be bonded by a hot press and has heat resistance necessary in a soldering process, which is a subsequent process, can be suitably used.
[0059]
In addition, when using what laminated | stacked the thermoplastic resin layer on the polyimide film, the thermal expansion coefficient of polyimide is about 15-20 ppm, and the thermal expansion coefficient of copper (17-20 ppm) often used as wiring Therefore, it is possible to prevent the occurrence of peeling and warping of the substrate.
[0060]
In the first embodiment, the interlayer connection material is the conductive paste 50, but may be granular or the like as long as the via hole can be filled.
[0061]
Moreover, in the said 1st Embodiment, although the multilayer substrate 100 was a 6 layer board | substrate, it cannot be overemphasized that the number of layers will not be limited if it has a some conductor pattern layer.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic manufacturing process of a multilayer substrate according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing a single-sided conductor pattern film to be laminated.
FIG. 3 is a cross-sectional view showing a schematic manufacturing process of a multilayer substrate according to a second embodiment of the present invention.
[Explanation of symbols]
21 Single-sided conductor pattern films 22, 22a, 22b, 26a, 26b Conductor pattern 23 Resin film 24 Via holes 32, 37 Electrode 50 Conductive paste (interlayer connection material)
100 multilayer board

Claims (3)

Preparing a conductive pattern film in which a conductive pattern is formed on at least one side of a resin film made of a thermoplastic resin ;
While positioning the resin film containing the conductive pattern film, a step of plurally stacked,
Temporarily fixing the plurality of resin films by temporarily melting at least a part of the laminated resin films, and temporarily fixing the plurality of resin films ;
A method of manufacturing a multilayer substrate comprising: a heating / pressurizing step of bonding the resin films to each other to form a multilayer substrate by pressing the temporarily fixed resin film while being heated by a hot press plate. ,
In the temporary fixing step, at least a part of the laminated resin film is heated and melted,
An annular conductor pattern is provided at least on the resin film located on the outermost surface so as to surround the periphery of the position where the resin film is heated and melted,
The temporary fixing step is performed around the heating member of all the resin films laminated so that the tip of the heated heating member reaches the lowermost resin film from the annular conductor pattern of the resin film located on the outermost surface. A method for producing a multilayer substrate, comprising melting the resin . In the temporary fixing step, a hole is formed in the resin film by a tip of the heating member, and the thermoplastic resin around the hole flows into the hole of the resin film by the heating / pressurizing step. The method for producing a multilayer substrate according to claim 1, wherein: Preparing a conductive pattern film in which a conductive pattern is formed on at least one side of a resin film made of a thermoplastic resin;
While positioning the resin film including the conductor pattern film, a step of laminating a plurality of sheets,
Temporarily fixing the plurality of resin films by temporarily melting at least a part of the laminated resin films, and temporarily fixing the plurality of resin films;
A method of manufacturing a multilayer substrate comprising: a heating / pressurizing step of bonding the resin films to each other to form a multilayer substrate by pressing the temporarily fixed resin film while being heated by a hot press plate. ,
In the temporary fixing step, after laminating all the number of resin films to be laminated, at least a part of the total number of resin films is heated and melted to temporarily fix all the number of resin films to be laminated. Done
An annular conductor pattern is provided on the resin film located at least on the outermost surface so as to surround the periphery of the position where the resin film is heated and melted,
In the temporary fixing step, the pressure was applied by applying pressure to the annular conductor pattern of the resin film in which the tip of the heated heating member is located on the outermost surface in the pressing direction of the heating / pressurizing step. A process for producing a multilayer substrate, wherein the conductive pattern is deformed so that a part of the conductor pattern bites into the resin film in the lower layer .

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