Resin film with conductor layer, laminated substrate, and method for manufacturing resin film with conductor layer

Abstract

A resin film (10) with a conductor layer has a resin film (1) containing a thermoplastic resin and provided with a void (1h) inside and a conductor layer (2) adjacent to at least one main surface side of the resin film (1). In the resin film (1), when a position of an end surface on the conductor layer (2) side is set as a first position (E1), a position at a distance of exactly 1 / 3 of the thickness of the resin film (1) from the first position (E1) in the stacking direction is set as a second position (E2), and a position at a distance of exactly 1 / 3 of the thickness of the resin film (1) from the second position (E2) in the stacking direction toward the side opposite to the first position (E1) is set as a third position (E3), the void (1h) is present more between the first position (E1) and the second position (E2) than between the second position (E2) and the third position (E3).

Description

Technical Field

[0001] This invention relates to a resin film with a conductive layer, a laminated substrate, and a method for manufacturing a resin film with a conductive layer. Background Technology

[0002] As a multilayer wiring substrate for various electronic devices, Patent Document 1 discloses a multilayer wiring substrate characterized in that the multilayer wiring substrate has a structure in which a ground layer or power layer and a signal layer are arranged in a manner separated by an insulating layer, the insulating layer is composed of a porous film with different porosities in the thickness direction, and the side of the porous film with higher porosity is arranged on the signal layer side.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2003-8233 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In multilayer wiring substrates such as those described in Patent Document 1, to improve dielectric properties in high-frequency regions, a technique is sometimes used whereby a porous film is used as an insulating layer, thereby reducing the dielectric constant of the insulating layer in accordance with the amount of voids present. For example, in the multilayer wiring substrate described in Patent Document 1, as described in the embodiments of Patent Document 1, a film is formed using a wet coagulation method with a film-forming solution containing a polyimide precursor, followed by a heat treatment to heat-close the polyimide precursor, and the resulting porous film is used as an insulating layer.

[0008] In order to further improve the dielectric properties in the high-frequency region of the multilayer wiring substrate described in Patent Document 1, the inventors investigated using a thermoplastic resin, such as a liquid crystal polymer, as the constituent material of a porous film. However, it is known that if a thermoplastic resin is used and a porous film is formed using the method described in the embodiments of Patent Document 1, the thermoplastic resin is prone to decomposition, or the shape of the pores is difficult to maintain due to the viscoelasticity of the thermoplastic resin. Thus, in the multilayer wiring substrate described in Patent Document 1, it is inherently difficult to realize a porous film containing a thermoplastic resin, and therefore there is room for improvement in terms of further improving the dielectric properties in the high-frequency region.

[0009] This invention was made to solve the aforementioned problems, and its object is to provide a resin film with a conductive layer that can improve dielectric properties in high-frequency regions by comprising a thermoplastic resin. Furthermore, this invention aims to provide a laminated substrate having the aforementioned resin film with a conductive layer. Additionally, this invention aims to provide a method for manufacturing the aforementioned resin film with a conductive layer.

[0010] Methods for solving problems

[0011] The resin film with a conductor layer of the present invention is characterized in that it comprises a resin film and a conductor layer in a lamination direction, the resin film comprising a thermoplastic resin and having pores therein, the conductor layer being adjacent to at least one main surface side of the resin film, wherein in the resin film, when the position of the end face of the conductor layer side is designated as a first position, the position in the lamination direction at a distance from the first position that is exactly 1 / 3 of the thickness of the resin film is designated as a second position, and the position in the lamination direction facing the opposite side to the first position at a distance from the second position that is exactly 1 / 3 of the thickness of the resin film is designated as a third position, the pores are mainly present between the first position and the second position in such a way that the number of pores between the first position and the second position is greater than the number of pores between the second position and the third position.

[0012] The laminated substrate of the present invention is characterized by having a resin film with a conductor layer as described in the present invention.

[0013] The method for manufacturing a resin film with a conductor layer according to the present invention is characterized by comprising the following steps: a step of forming a laminate by providing a conductor layer adjacent to at least one main surface side of a resin film comprising a thermoplastic resin, the laminate having the resin film and the conductor layer in a lamination direction; and a step of providing pores in the interior of the resin film by heat treating the laminate, wherein in the step of providing pores, when the end face of the conductor layer side is designated as a first position, a second position is designated as a position in the lamination direction at a distance from the first position that is exactly 1 / 3 of the thickness of the resin film, and a third position is designated as a position in the lamination direction facing the opposite side to the first position at a distance from the second position that is exactly 1 / 3 of the thickness of the resin film, the pores mainly existing between the first position and the second position are provided in such a way that the number of pores between the first position and the second position is greater than the number of pores between the second position and the third position.

[0014] Invention Effects

[0015] According to the present invention, a resin film with a conductive layer, comprising a thermoplastic resin, can be provided to improve dielectric properties in the high-frequency region. Furthermore, according to the present invention, a laminated substrate having the aforementioned resin film with a conductive layer can be provided. Additionally, according to the present invention, a method for manufacturing the aforementioned resin film with a conductive layer can be provided. Attached Figure Description

[0016] Figure 1This is a cross-sectional schematic diagram illustrating an example of a resin film with a conductor layer according to the present invention.

[0017] Figure 2 This is a cross-sectional schematic diagram showing a process for fabricating a laminate, which is an example of a method for manufacturing a resin film with a conductor layer according to the present invention.

[0018] Figure 3 This is a cross-sectional schematic diagram showing a process for fabricating a laminate, which is an example of a method for manufacturing a resin film with a conductor layer according to the present invention.

[0019] Figure 4 This is a cross-sectional schematic diagram showing a process for fabricating a laminate, which is an example of a method for manufacturing a resin film with a conductor layer according to the present invention.

[0020] Figure 5 This refers to an example of a resin film with a conductor layer as described in the present invention. Figure 1 Cross-sectional diagrams of different examples.

[0021] Figure 6 This refers to an example of a resin film with a conductor layer as described in the present invention. Figure 1 and Figure 5 Cross-sectional diagrams of different examples.

[0022] Figure 7 This is a cross-sectional schematic diagram illustrating an example of a laminated substrate according to the present invention.

[0023] Figure 8 This is a cross-sectional schematic diagram showing a process for fabricating a resin film with a conductor layer, as an example of a method for manufacturing a laminated substrate according to the present invention.

[0024] Figure 9 This is a cross-sectional schematic diagram showing a process for fabricating a resin film with a conductor layer, as an example of a method for manufacturing a laminated substrate according to the present invention.

[0025] Figure 10 This is a cross-sectional schematic diagram showing a process for fabricating a resin film with a conductor layer, as an example of a method for manufacturing a laminated substrate according to the present invention.

[0026] Figure 11 This is a cross-sectional schematic diagram showing a process for forming through holes, as an example of a method for manufacturing a laminated substrate according to the present invention.

[0027] Figure 12 This is a cross-sectional schematic diagram showing a process for forming through holes, as an example of a method for manufacturing a laminated substrate according to the present invention.

[0028] Figure 13 This is a cross-sectional schematic diagram showing a step of filling a conductive paste, which is an example of a method for manufacturing a laminated substrate according to the present invention.

[0029] Figure 14 This is a cross-sectional schematic diagram showing a step of filling a conductive paste, which is an example of a method for manufacturing a laminated substrate according to the present invention.

[0030] Figure 15 This is a cross-sectional schematic diagram showing a step in forming interlayer interconnect conductors, as an example of a method for manufacturing a multilayer substrate according to the present invention.

[0031] Figure 16 This refers to an example of a laminated substrate used in this invention, and... Figure 7 Cross-sectional diagrams of different examples.

[0032] Figure 17 This refers to an example of a laminated substrate used in this invention, and... Figure 7 and Figure 16 Cross-sectional diagrams of different examples.

[0033] Figure 18 This refers to an example of a laminated substrate used in this invention, and... Figure 7 , Figure 16 and Figure 17 Cross-sectional diagrams of different examples.

[0034] Figure 19 This refers to an example of a laminated substrate used in this invention, and... Figure 7 , Figure 16 , Figure 17 and Figure 18 Cross-sectional diagrams of different examples. Detailed Implementation

[0035] The following describes the resin film with a conductor layer, the laminated substrate, and the method for manufacturing the resin film with a conductor layer according to the present invention. It should be noted that the present invention is not limited to the following structures, and appropriate modifications can be made without departing from the spirit of the invention. Furthermore, inventions combining the preferred configurations described below are also part of the present invention.

[0036] The resin film with a conductor layer of the present invention is characterized in that it comprises a resin film and a conductor layer in a lamination direction, the resin film comprising a thermoplastic resin and having pores therein, the conductor layer being adjacent to at least one main surface side of the resin film, wherein in the resin film, when the position of the end face of the conductor layer side is designated as a first position, the position in the lamination direction at a distance from the first position that is exactly 1 / 3 of the thickness of the resin film is designated as a second position, and the position in the lamination direction facing the opposite side to the first position at a distance from the second position that is exactly 1 / 3 of the thickness of the resin film is designated as a third position, the pores are mainly present between the first position and the second position in such a way that the number of pores between the first position and the second position is greater than the number of pores between the second position and the third position.

[0037] Figure 1 This is a cross-sectional schematic diagram illustrating an example of a resin film with a conductor layer according to the present invention.

[0038] Figure 1 The resin film 10 with a conductor layer shown has a resin film 1 and a conductor layer 2 in the stacking direction.

[0039] In this instruction manual, "film" and "sheet" have the same meaning and are not distinguished based on thickness.

[0040] In this specification, the lamination direction corresponds to the direction along the thickness direction of the resin film constituting the conductor layer.

[0041] The resin film 1 has a first main surface 1a and a second main surface 1b that are opposite each other in the thickness direction HD.

[0042] The thickness of the resin film 1 is preferably 10 μm or more and 250 μm or less.

[0043] The first direction MD and the second direction TD are contained in in-plane directions orthogonal to the thickness direction HD. More specifically, the first direction MD is a direction orthogonal to the thickness direction HD, and the second direction TD is a direction orthogonal to both the thickness direction HD and the first direction MD. That is, the thickness direction HD, the first direction MD, and the second direction TD are mutually orthogonal.

[0044] The conductor layer 2 is adjacent to at least one main surface side of the resin film 1, here the first main surface 1a side. More specifically, the conductor layer 2 is disposed on the first main surface 1a of the resin film 1.

[0045] Examples of materials that can be used to form conductor layer 2 include copper, silver, aluminum, stainless steel, nickel, gold, and alloys containing at least one of these metals.

[0046] Conductor layer 2 is formed, for example, of a metal foil, preferably of copper foil. In this case, a metal other than copper may be present on the surface of the copper foil.

[0047] Resin film 1 contains thermoplastic resin.

[0048] Examples of thermoplastic resins contained in resin film 1 include liquid crystal polymer (LCP), fluoropolymer, thermoplastic polyimide resin, polyether ether ketone resin (PEEK), polyphenylene sulfide resin (PPS), cyclic polyolefin resin (COP), and polyphenylene ether resin (PPE).

[0049] The thermoplastic resin contained in resin film 1 is preferably a liquid crystal polymer. That is, resin film 1 is preferably a liquid crystal polymer film. Liquid crystal polymers also have the characteristics of low dielectric constant and low hygroscopicity among thermoplastic resins. Therefore, in the laminated substrate made using liquid crystal polymer films, the effects brought by liquid crystal polymers, such as easy improvement of dielectric properties in high-frequency regions and less susceptibility to changes in dielectric properties caused by moisture absorption, can be easily utilized.

[0050] When manufacturing a laminated substrate using a liquid crystal polymer film and a conductor layer, for example, when forming an interlayer connection conductor connected to the conductor layer by plating through-holes in the liquid crystal polymer film, the interlayer connection conductor sometimes cracks due to stress applied from the liquid crystal polymer film. Similarly, when manufacturing a laminated substrate using a structure in which conductive paste is filled in through-holes in a liquid crystal polymer film with a conductor layer, the interlayer connection conductor, which is the cured conductive paste, sometimes cracks due to stress applied from the liquid crystal polymer film. As a result, the connection reliability of the interlayer connection conductors in laminated substrates manufactured using liquid crystal polymer films is sometimes reduced.

[0051] In contrast, when resin film 1 is a liquid crystal polymer film, for resin film 1, in the state after decomposition with supercritical methanol... 13 When the integrated value of the peak from the benzene ring in the C-NMR spectrum is set as CA, the integrated value of the peak from the naphthalene ring is set as CB, and the integrated value of the peak from the carboxymethyl group is set as CC, the ratio (CA+CB) / CC is preferably 1.25 or higher and 1.65 or lower.

[0052] In liquid crystal polymer films, by setting (CA+CB) / CC to 1.65 or less, the coefficient of linear expansion in the thickness direction can be reduced. Furthermore, by setting (CA+CB) / CC to 1.25 or more, the processing of the film itself becomes easier, and the processability when manufacturing a laminated substrate using the liquid crystal polymer film is also improved. Therefore, by setting (CA+CB) / CC to 1.25 or more and 1.65 or less, the coefficient of linear expansion in the thickness direction in liquid crystal polymer films can be reduced, thereby improving the processability of the film and the processability when manufacturing a laminated substrate using the liquid crystal polymer film.

[0053] When a multilayer substrate with interlayer interconnect conductors is manufactured using a liquid crystal polymer film with a (CA+CB) / CC ratio of 1.25 or higher and 1.65 or lower, the small coefficient of linear expansion in the thickness direction of the liquid crystal polymer film makes it less likely to apply stress from the liquid crystal polymer film to the interlayer interconnect conductors. Therefore, in multilayer substrates manufactured using liquid crystal polymer films with a (CA+CB) / CC ratio of 1.25 or higher and 1.65 or lower, cracking of the interlayer interconnect conductors is less likely, resulting in less degradation of the connection reliability of the interlayer interconnect conductors.

[0054] Furthermore, when using a liquid crystal polymer film with a (CA+CB) / CC ratio of 1.25 or higher and 1.65 or lower to manufacture a laminated substrate by a one-to-one lamination method, the hot pressing temperature can be reduced without increasing it, thus the liquid crystal polymer is less prone to decomposition during hot pressing.

[0055] In liquid crystal polymer films, if (CA+CB) / CC is less than 1.25, the constituent material is hard and difficult to deform, so the processing of the film state itself sometimes becomes difficult. In addition, the processability is sometimes reduced when using liquid crystal polymer films to manufacture laminated substrates.

[0056] In liquid crystal polymer films, if (CA+CB) / CC is greater than 1.65, the coefficient of linear expansion in the thickness direction becomes larger. Therefore, in laminated substrates with interlayer interconnect conductors manufactured using liquid crystal polymer films, the connection reliability of the interlayer interconnect conductors is sometimes reduced.

[0057] In the liquid crystal polymer film, (CA+CB) / CC is preferably 1.35 or higher and 1.65 or lower.

[0058] (CA+CB) / CC is calculated as follows.

[0059] First, for a liquid crystal polymer film with a conductor layer, the liquid crystal polymer film is removed by etching the conductor layer. Alternatively, after removing the liquid crystal polymer film with a conductor layer from a laminated substrate having the liquid crystal polymer film with a conductor layer, the conductor layer of the removed liquid crystal polymer film with a conductor layer is etched to remove the liquid crystal polymer film.

[0060] Next, the liquid crystal polymer film and methanol are placed in a high-temperature, high-pressure reactor. The reactor is then heated after purging the system with argon, resulting in a solution containing the liquid crystal polymer film. If the reactor is a closed system, methanol vaporizes simply by heating the system to, for example, above 240°C, and the system reaches the critical pressure of methanol, thus making the methanol in a supercritical state. The solution is then vacuum-dried to remove the solvent, yielding a powder of the liquid crystal polymer film decomposed by supercritical methanol. This powder is then dissolved, for example, at a ratio of 0.02 g of deuterated methanol per 1 ml, to obtain a sample for NMR analysis.

[0061] Next, NMR measurements were performed on the sample used for NMR determination, thereby obtaining... 13 C-NMR spectrum. Then, based on 13 The integrated values ​​of the peaks from the benzene ring, the naphthalene ring, and the carboxymethyl group were obtained from the C-NMR spectra and denoted as CA, CB, and CC, respectively.

[0062] Here, for example, when the liquid crystal polymer constituting the liquid crystal polymer film contains only type II fully aromatic polyester, the peaks from the benzene ring, and more specifically from methyl p-hydroxybenzoate, correspond to peaks with chemical shifts in the range of 113 ppm or more and 115 ppm or less (114 ± 1 ppm). Additionally, the peaks from the naphthalene ring, and more specifically from methyl 6-hydroxy-2-naphthoate, correspond to peaks with chemical shifts in the range of 107 ppm or more and 109 ppm or less (108 ± 1 ppm). Furthermore, the peaks from the carboxymethyl group, and more specifically from the methyl group of the ester, correspond to peaks with chemical shifts in the range of 49 ppm or more and 51 ppm or less (50 ± 1 ppm).

[0063] Calculate (CA+CB) / CC based on CA, CB, and CC obtained above.

[0064] Alternatively, (CA+CB) / CC can be calculated based on the converted values ​​of CA, CB, and CC obtained by setting the integral value of the peak from deuterated methanol to 100.

[0065] The (CA+CB) / CC ratio can be controlled, for example, by using multiple fully aromatic polyesters with different monomer primary structures as liquid crystal polymers during the manufacture of the liquid crystal polymer film, and by adjusting the blending ratio of these liquid crystal polymers. Alternatively, liquid crystal polymers with monomer primary structures having a (CA+CB) / CC ratio in the range of 1.25 or higher and 1.65 or lower can also be used during the manufacture of the liquid crystal polymer film.

[0066] The following explains the further effects of liquid crystal polymer films with a (CA+CB) / CC ratio of 1.25 or higher and 1.65 or lower.

[0067] As an existing method for reducing the coefficient of linear expansion in the thickness direction of a liquid crystal polymer film, there is a method of using a liquid crystal polymer with a small coefficient of volume expansion when manufacturing the liquid crystal polymer film. However, in addition to this method, there are other methods.

[0068] As another existing method, there is a method of using a mixed resin of liquid crystal polymer and inorganic filler to form a liquid crystal polymer film.

[0069] However, due to the high surface activity of inorganic fillers, moisture is easily adsorbed onto their surfaces. Therefore, in laminated substrates manufactured using liquid crystal polymer films containing inorganic fillers, the dielectric properties are prone to change due to moisture absorption. In contrast, to reduce the surface activity of inorganic fillers, surface treatments such as coupling agents are sometimes performed, but even with such treatments, it is impossible to sufficiently suppress moisture adsorption onto the surface of the inorganic fillers. Furthermore, the elongation at break of liquid crystal polymer films tends to decrease when containing inorganic fillers.

[0070] In contrast, liquid crystal polymer films with a (CA+CB) / CC ratio of 1.65 or less can reduce the coefficient of linear expansion in the thickness direction. That is, to reduce the coefficient of linear expansion in the thickness direction, liquid crystal polymer films with a (CA+CB) / CC ratio of 1.65 or less can be free of inorganic fillers. Therefore, in liquid crystal polymer films with conductive layers having a (CA+CB) / CC ratio of 1.65 or less, and in laminated substrates having such conductive layers, changes in dielectric properties due to moisture absorption are less likely to occur. Furthermore, the elongation at break of the liquid crystal polymer film is less likely to decrease.

[0071] As another existing method, there is a method of crosslinking liquid crystal polymer films by irradiating them with ionizing radiation.

[0072] However, in order to reduce the coefficient of linear expansion in the thickness direction of the liquid crystal polymer film, a high dose of ionizing radiation is required, which increases the manufacturing cost of the liquid crystal polymer film.

[0073] In contrast, in liquid crystal polymer films with a (CA+CB) / CC ratio of 1.65 or less, the coefficient of linear expansion in the thickness direction can be reduced. That is, when manufacturing liquid crystal polymer films with a (CA+CB) / CC ratio of 1.65 or less, high doses of ionizing radiation can be avoided to reduce the coefficient of linear expansion in the thickness direction. This allows for the reduction of manufacturing costs for liquid crystal polymer films.

[0074] In liquid crystal polymer films, for samples used in NMR measurements 13 When the integral value of the peak from deuterated methanol in the C-NMR spectrum is set to 100, CA is preferably 1.05 or higher and 1.80 or lower. The sample used for NMR determination is obtained by dissolving powder of the decomposition product of liquid crystal polymer film after supercritical methanol decomposition at a ratio of 0.02 g of deuterated methanol per 1 ml.

[0075] In liquid crystal polymer films, if CA is less than 1.05 under the above conditions, the storage modulus may sometimes increase.

[0076] In liquid crystal polymer films, if CA is greater than 1.80 under the above conditions, the coefficient of linear expansion in the thickness direction may sometimes increase.

[0077] In liquid crystal polymer films, for samples used in NMR measurements 13 When the integral value of the peak from deuterated methanol in the C-NMR spectrum is set to 100, the CB value is preferably 1.20 or higher and 1.70 or lower. The sample used for NMR determination is obtained by dissolving powder of the decomposition product of the liquid crystal polymer film after supercritical methanol decomposition at a ratio of 0.02 g of deuterated methanol per 1 ml.

[0078] In liquid crystal polymer films, if the CB under the above conditions is less than 1.20, the coefficient of linear expansion in the thickness direction may sometimes increase.

[0079] In liquid crystal polymer films, if the CB is greater than 1.70 under the above conditions, the storage modulus may sometimes increase.

[0080] In liquid crystal polymer films, for samples used in NMR measurements 13 When the integral value of the peak from deuterated methanol in the C-NMR spectrum is set to 100, the C-NMR value is preferably 1.60 or higher and 2.50 or lower. The sample used for NMR determination is obtained by dissolving powder of the decomposition product of liquid crystal polymer film after supercritical methanol decomposition at a ratio of 0.02 g of deuterated methanol per 1 ml.

[0081] In liquid crystal polymer films, if the CC is less than 1.60 under the above conditions, the storage modulus may sometimes increase.

[0082] In liquid crystal polymer films, if the CC value under the above conditions is greater than 2.50, the coefficient of linear expansion in the thickness direction may sometimes increase.

[0083] The peaks from deuterated methanol correspond to peaks in the range of chemical shifts above 47 ppm and below 48 ppm (47.5 ± 0.5 ppm).

[0084] The resin membrane 1 has pores 1h inside.

[0085] In the resin film 10 with a conductive layer, by providing a void 1h inside the resin film 1, the dielectric constant of the resin film 1 is reduced. As a result, the dielectric properties in the high-frequency region of the laminated substrate manufactured using the resin film 10 with a conductive layer are improved. Furthermore, when the resin film 1 is a liquid crystal polymer film, the dielectric properties in the high-frequency region of the laminated substrate are significantly improved in combination with the effects brought by the liquid crystal polymer.

[0086] In the resin film 10 with a conductor layer, in the resin film 1, when the end face on the side of the conductor layer 2, here the first main face 1a, is designated as the first position E1, the position in the stacking direction at a distance from the first position E1 that is exactly 1 / 3 of the thickness of the resin film 1 is designated as the second position E2, and the position in the stacking direction facing the opposite side to the first position E1 at a distance from the second position E2 that is exactly 1 / 3 of the thickness of the resin film 1 is designated as the third position E3, the voids 1h are mainly present between the first position E1 and the second position E2 in such a way that the number of voids between the first position E1 and the second position E2 is greater than the number of voids between the second position E2 and the third position E3.

[0087] In the resin film 10 with a conductor layer, the void 1h is mainly located between the first position E1 and the second position E2, as described above, and thus the void 1h is mainly located near the conductor layer 2. In the laminated substrate manufactured using the resin film 10 with a conductor layer, if the conductor layer 2 is a signal line for transmitting signals, and the void 1h is mainly located near the conductor layer 2 where the signal line is located, the dielectric constant near the signal line is reduced. Therefore, the transmission loss in the high-frequency region is easily reduced, resulting in improved transmission characteristics in the high-frequency region.

[0088] In this specification, the second position in the resin film is determined by a plane extending in an in-plane direction orthogonal to the lamination direction, located at a distance from the interface between the resin film contained in the first position and the conductor layer that is exactly 1 / 3 of the thickness of the resin film overlapping the conductor layer in the lamination direction.

[0089] In this specification, the third position in the resin film is determined by a plane extending in an in-plane direction orthogonal to the lamination direction, located at a distance from the second position that is exactly one-third the thickness of the same resin film as when the second position was determined, on the side opposite to the first position in the lamination direction.

[0090] The number of voids between the first and second positions is determined as follows. First, for resin films with conductive layers, or resin films of laminated substrates with conductive layers as described later, after confirming in advance the presence of voids by observing the area from the thickness direction, a cross-sectional image along the thickness direction is captured using a scanning electron microscope (SEM) when viewing the area between the first and second positions in the in-plane direction. Cross-sectional images of the area between the first and second positions in the resin film are captured at 5 to 10 different locations in the in-plane direction. The size of each cross-sectional image is set to 75 μm x 125 μm (e.g., the field of view size when viewed at 1000x magnification). Furthermore, by performing image analysis on all captured cross-sectional images using image analysis software, the number of voids in all cross-sectional images is counted, and the average value of each cross-sectional image (one field of view) calculated based on the total number of voids is determined as the number of voids between the first and second positions.

[0091] The number of voids between positions 2 and 3 is determined in the same way as the number of voids between positions 1 and 2. It should be noted that in all cross-sectional images (5 to 10 cross-sectional images) taken with the area between positions 2 and 3 in the resin film as the object, if the existence of voids cannot be confirmed, the number of voids between positions 2 and 3 is set to 0.

[0092] In this specification, the vias are primarily located between positions 1 and 2, similar to the multilayer wiring substrate described in Patent Document 1 (refer to Patent Document 1). Figure 1 The difference refers to the state where the number of voids between the first and second positions is much greater than the number of voids between the second and third positions. Preferably, it refers to the state where the number of voids between the second and third positions is less than 1 / 5 of the number of voids between the first and second positions.

[0093] In the resin film 1, when the fourth position (not shown) is located at a distance of exactly 1 / 4 of the thickness of the resin film 1 from the first position E1 in the stacking direction, and the fifth position (not shown) is located at a distance of exactly 1 / 4 of the thickness of the resin film 1 from the fourth position on the opposite side of the first position E1 in the stacking direction, the voids 1h preferably exist primarily between the first position E1 and the fourth position in such a way that the number of voids between the first position E1 and the fourth position is greater than the number of voids between the fourth position and the fifth position. In this case, the transmission characteristics in the high-frequency region of the laminated substrate manufactured using the resin film 10 with a conductor layer become easier to improve.

[0094] On the other hand, if the voids 1h do not primarily exist between the first position E1 and the second position E2, but rather permeate the entire thickness direction HD of the resin film 1, the mechanical strength of the resin film 1, and even the mechanical strength of the resin film 10 with the conductor layer, will decrease. From this viewpoint, it is preferable that voids 1h are substantially absent between the second position E2 and the third position E3. Substantially, the absence of voids between the second and third positions means that the number of voids between the second and third positions is 5 or less, preferably 3 or less.

[0095] It should be noted that, as Figure 1 As shown, the pore 1h can exist only between the first position E1 and the second position E2.

[0096] As described above, according to the resin film 10 with a conductor layer, a resin film with a conductor layer that can improve dielectric properties in the high-frequency region can be realized with a composition including a thermoplastic resin.

[0097] The diameter of the pore 1h existing between the first position E1 and the second position E2 is preferably 20 μm or less.

[0098] If the pore diameter of the pore 1h is less than 20μm, the mechanical strength of the resin film 1, or even the mechanical strength of the resin film 10 with the conductor layer, is not easily reduced.

[0099] On the other hand, if the void 1h is mainly located near the conductor layer 2, the adhesion between the resin film 1 and the conductor layer 2 may be reduced due to the void 1h. In contrast, if the diameter of the void 1h is less than 20 μm, the adhesion between the resin film 1 and the conductor layer 2 is not easily reduced even if the void 1h is mainly located near the conductor layer 2.

[0100] If the pore diameter of pore 1h is greater than 20 μm, the mechanical strength of resin film 1, and even the mechanical strength of resin film 10 with conductor layer, may decrease. In addition, if the pore diameter of pore 1h is greater than 20 μm, the adhesion between resin film 1 and conductor layer 2 may decrease.

[0101] The diameter of the pore in the pore 1h is preferably 5μm or more.

[0102] If the diameter of the void 1h is less than 5 μm, the number of voids 1h used to achieve the same porosity becomes excessive compared to the case where the diameter of the void 1h is 5 μm or more. Therefore, when the resin film with the conductor layer or the laminated substrate with the resin film with the conductor layer is bent, the void 1h sometimes becomes a source of cracks, resulting in a decrease in the mechanical strength of the resin film with the conductor layer or the laminated substrate with the resin film with the conductor layer.

[0103] The diameter of the void between the first and second positions is determined as follows: First, for a resin film with a conductive layer, or a resin film of a laminated substrate having a conductive layer as described later, after confirming in advance that the area where the void exists is observed in the thickness direction, a cross-sectional image along the thickness direction is taken using a scanning electron microscope when viewing the area between the first and second positions in the in-plane direction. Cross-sectional images of the area between the first and second positions in the resin film are taken at 5 to 10 different locations in the in-plane direction. The size of each cross-sectional image is set to 75 μm x 125 μm (e.g., the field of view size when viewed at 1000x magnification). Then, by performing image analysis on all the captured cross-sectional images using image analysis software, the equivalent circle diameter of all voids in all the cross-sectional images is determined, and the maximum value among the obtained measurements is determined as the diameter of the void between the first and second positions.

[0104] In the viscoelastic properties representing the relationship between the loss tangent of the resin film 1 and temperature, the integral value of the loss tangent over the temperature range from 40°C to the melting point of the thermoplastic resin contained in the resin film is preferably 29.7 or less.

[0105] Regarding the resin film, the integral value of the loss tangent over the temperature range from 40°C to the melting point of the thermoplastic resin contained in the resin film is obtained as follows. First, for a resin film with a conductor layer, the resin film is removed by etching the conductor layer. Alternatively, after removing the resin film with a conductor layer from a laminated substrate containing a resin film with a conductor layer as described later, the conductor layer is etched onto the removed resin film with the conductor layer, thereby removing the resin film. Next, using a dynamic viscoelasticity measuring device, the temperature dependence of the loss tangent of the resin film is measured over the temperature range from at least 40°C to the melting point of the thermoplastic resin contained in the resin film, thereby obtaining a graph showing the relationship between the loss tangent of the resin film and temperature. Then, for the graph showing the relationship between the loss tangent of the resin film and temperature, the integral value of the loss tangent is obtained by integrating over the temperature range from 40°C to the melting point of the thermoplastic resin contained in the resin film.

[0106] The melting point of the thermoplastic resin contained in the resin film was determined as follows. First, the resin film was heated to complete melting using a differential scanning calorimeter. Next, the resulting melt was cooled and then heated again. The temperature corresponding to the endothermic peak observed during this heating process was then determined as the melting point of the thermoplastic resin contained in the resin film. It should be noted that when the endothermic peak is difficult to observe using the above method, the melting point of the thermoplastic resin contained in the resin film was determined by textural observation under orthogonal Nicol conditions using a polarizing microscope.

[0107] If the integral value of the loss tangent of the resin film 1 under the above conditions is 29.7 or less, then the viscous component of the loss tangent in the viscoelastic properties of the resin film 1 is low, and it is not easily softened even at high temperatures. The effect obtained when the resin film 1 has such properties is shown. Figure 1 An example of a method for manufacturing the resin film 10 with a conductor layer is shown and will be described below.

[0108] The method for manufacturing a resin film with a conductor layer according to the present invention is characterized by comprising the following steps: a step of forming a laminate by providing a conductor layer adjacent to at least one main surface side of a resin film comprising a thermoplastic resin, the laminate having the resin film and the conductor layer in a lamination direction; and a step of providing pores in the interior of the resin film by heat treating the laminate, wherein in the step of providing pores, when the end face of the conductor layer side is designated as a first position, a second position is designated as a position in the lamination direction at a distance from the first position that is exactly 1 / 3 of the thickness of the resin film, and a third position is designated as a position in the lamination direction facing the opposite side to the first position at a distance from the second position that is exactly 1 / 3 of the thickness of the resin film, the pores mainly existing between the first position and the second position are provided in such a way that the number of pores between the first position and the second position is greater than the number of pores between the second position and the third position.

[0109] <Processes for creating laminated structures>

[0110] Figure 2 , Figure 3 and Figure 4 This is a cross-sectional schematic diagram showing a process for fabricating a laminate, which is an example of a method for manufacturing a resin film with a conductor layer according to the present invention.

[0111] First, such as Figure 2 As shown, a resin film 1 containing thermoplastic resin is prepared. (As illustrated...) Figure 2 As shown, the first main surface 1a of the resin film 1 is not a completely flat surface, but is provided with a rough surface with unevenness.

[0112] Resin film 1, such as a liquid crystal polymer film, is manufactured using a resin material incorporating a liquid crystal polymer, by a known method as described in Japanese Patent Application Publication No. 2-3430. As film-forming methods for resin film 1, such as a liquid crystal polymer film, T-die stretching, laminate stretching, and blow molding are industrially advantageous.

[0113] In addition, such as Figure 3 As shown, prepare conductor layer 2.

[0114] Then, as Figure 4 As shown, a laminate 15 having a resin film 1 and a conductor layer 2 in the lamination direction is produced by providing a conductor layer 2 adjacent to at least one main surface side of the resin film 1, here the first main surface 1a side. At this time, for example, the conductor layer 2 is pressed onto the first main surface 1a of the resin film 1.

[0115] In the laminate 15, since the first main surface 1a of the resin film 1 is a rough surface, a space 15h is provided between the resin film 1 and the conductor layer 2 in the in-plane direction.

[0116] In the process of manufacturing the laminate, the arithmetic mean height Sa of the main surface of the resin film 1 on the side where the conductor layer 2 is provided, which is the first main surface 1a in this case, is preferably 240 nm or more.

[0117] If the arithmetic mean height Sa of the main surface 1 of the resin film 1 on the side where the conductor layer 2 is located, here the first main surface 1a, is 240 nm or more, it is easy to create a space 15h between the resin film 1 and the conductor layer 2 over a larger area. As a result, in the process of creating voids described later, voids from the space 15h are more likely to be created in the vicinity of the conductor layer 2 in the resin film 1. Therefore, in the resin film with the conductor layer obtained subsequently, the number of voids near the conductor layer 2 in the resin film 1 tends to increase.

[0118] In the process of manufacturing the laminate, the arithmetic mean height Sa of the main surface of the resin film 1 on the side where the conductor layer 2 is provided, which is the first main surface 1a in this case, is preferably 350 nm or less.

[0119] The arithmetic mean height Sa of the main surface of the resin film on the side where the conductor layer is located is determined as follows. First, for the portion of the main surface of the resin film where the conductor layer is to be located, images of nine fields of view are captured using a non-contact laser microscope at 20x magnification. Then, image analysis software is used to analyze all the captured images, thereby determining the arithmetic mean height Sa of the main surface of the resin film in each image. The maximum value among the obtained measurements is determined as the arithmetic mean height Sa of the main surface of the resin film on the side where the conductor layer is located.

[0120] <Process for setting up holes>

[0121] By heat-treating the laminate 15, pores are formed inside the resin film 1. When the laminate 15 is heat-treated, the resin film 1 flows, thereby introducing spaces 15h inside the resin film 1. As a result, pores from the spaces 15h are formed inside the resin film 1. More specifically, as... Figure 1As shown, in the resin film 1, when the end face on the conductor layer 2 side, here the first main surface 1a, is designated as the first position E1, the position in the stacking direction at a distance from the first position E1 that is exactly 1 / 3 of the thickness of the resin film 1 is designated as the second position E2, and the position in the stacking direction facing the opposite side to the first position E1 at a distance from the second position E2 that is exactly 1 / 3 of the thickness of the resin film 1 is designated as the third position E3, the number of voids between the first position E1 and the second position E2 is greater than the number of voids between the second position E2 and the third position E3, the voids 1h that are mainly present between the first position E1 and the second position E2 are set in such a way that the number of voids between the first position E1 and the second position E2 is greater than the number of voids between the second position E2 and the third position E3.

[0122] Through the above operations, manufacturing Figure 1 The resin film 10 with a conductor layer is shown.

[0123] As described above, in the viscoelastic properties representing the relationship between the loss tangent of the resin film 1 and temperature, if the integral value of the loss tangent in the temperature range from 40°C to the melting point of the thermoplastic resin is 29.7 or less, then the viscous component of the loss tangent in the viscoelastic properties of the resin film 1 is low, and it is not easily softened even at high temperatures. If the resin film 1 has such properties, it is not easily softened, and therefore it is easy to maintain the uneven shape of the first main surface 1a of the resin film 1. Therefore, in the above-described process of setting the pores, even if the laminate 15 is heat-treated, the gas contained in the space 15h starting from the unevenness of the first main surface 1a of the resin film 1 is difficult to be discharged to the outside of the resin film 1. As a result, the gas contained in the space 15h easily enters the interior of the resin film 1, and therefore, as Figure 1 As shown, it is easy to set a pore 1h inside the resin film 1, more specifically near the conductor layer 2.

[0124] In the resin film with a conductor layer of the present invention, such as Figure 1 As shown in the resin film 10 with a conductor layer, the conductor layer can be a planar shape with the conductor layer extended on one side, but the conductor layer can also be a patterned shape with wiring or the like.

[0125] Figure 5 This refers to an example of a resin film with a conductor layer as described in the present invention. Figure 1 Cross-sectional diagrams of different examples.

[0126] Figure 5 The resin film 10' shown has a resin film 1 and a conductor layer 2' in the stacking direction.

[0127] The conductor layer 2' is adjacent to the first main surface 1a side of the resin film 1. More specifically, the conductor layer 2' is disposed on a portion of the first main surface 1a of the resin film 1.

[0128] The conductor layer 2' is formed, for example, by etching a patterned conductor layer after it has been pressed onto the first main surface 1a of the resin film 1. Alternatively, the conductor layer 2' can also be formed by pressing a pre-patterned conductor layer onto the first main surface 1a of the resin film 1.

[0129] In the resin film 10' with the conductor layer, in the resin film 1, when the end face on the conductor layer 2' side, here the first main surface 1a, is designated as the first position E1, the position in the stacking direction at a distance from the first position E1 that is exactly 1 / 3 of the thickness of the resin film 1 is designated as the second position E2, and the position in the stacking direction facing the opposite side to the first position E1 at a distance from the second position E2 that is exactly 1 / 3 of the thickness of the resin film 1 is designated as the third position E3, the voids 1h are mainly present between the first position E1 and the second position E2 in such a way that the number of voids between the first position E1 and the second position E2 is greater than the number of voids between the second position E2 and the third position E3.

[0130] In the resin film 10' with the conductor layer, the pores 1h exist not only near the area where the conductor layer 2' is provided on the first main surface 1a of the resin film 1, but also near the area where the conductor layer 2' is not provided. That is, in the resin film 10' with the conductor layer, the pores 1h exist not only in the area that overlaps with the conductor layer 2' when viewed from the thickness direction HD, but also in the area that does not overlap with the conductor layer 2' when viewed from the thickness direction HD.

[0131] The resin film with a conductor layer of the present invention can be as follows: Figure 1 The resin film 10 with a conductor layer shown has a conductor layer adjacent only to one main side of the resin film, but it may also have other conductor layers adjacent to the other main side of the resin film in addition to the conductor layer adjacent to one main side of the resin film.

[0132] Figure 6 This refers to an example of a resin film with a conductor layer as described in the present invention. Figure 1 and Figure 5 Cross-sectional diagrams of different examples.

[0133] Figure 6 The resin film 10” shown has a resin film 1”, a conductor layer 2” and a conductor layer 2” in the stacking direction.

[0134] The resin film 1” has a first main surface 1a” and a second main surface 1b” that are opposite each other in the thickness direction HD”.

[0135] The conductor layer 2 is adjacent to the first main surface 1a” of the resin film 1”. More specifically, the conductor layer 2 is disposed on the first main surface 1a” of the resin film 1”.

[0136] The conductor layer 2” is adjacent to the second main surface 1b” of the resin film 1”. More specifically, the conductor layer 2” is disposed on the second main surface 1b” of the resin film 1”.

[0137] "Resin film 1" contains thermoplastic resin.

[0138] The resin membrane 1” has pores 1h inside.

[0139] In the resin film 10” with a conductor layer, when the end face of the conductor layer 2 (here, the first main face 1a”) is designated as position 1 E1, the position in the lamination direction at a distance from position 1 E1 that is exactly 1 / 3 of the thickness of the resin film 1” is designated as position 2 E2, and the position in the lamination direction facing the opposite side to position 1 E1 at a distance from position 2 E2 that is exactly 1 / 3 of the thickness of the resin film 1” is designated as position 3 E3, the voids 1h are mainly present between positions 1 E1 and 2 E2 in such a way that the number of voids between positions 1 E1 and 2 E2 is greater than the number of voids between positions 2 E2 and 3 E3. That is, in the resin film 10” with a conductor layer, the voids 1h are mainly present near the conductor layer 2.

[0140] In the resin film 10” with a conductor layer, in addition to the pores 1h”, there are also pores 1h” inside the resin film 1”. In the resin film 10” with a conductor layer, when the end face of the conductor layer 2” side, which is here the second main face 1b”, is designated as the first position E1”, the position in the stacking direction that is exactly 1 / 3 of the thickness of the resin film 1” at a distance from the first position E1” in the stacking direction is designated as the second position E2”, and the position in the stacking direction that is exactly 1 / 3 of the thickness of the resin film 1” at a distance from the second position E2” on the opposite side of the first position E1” in the stacking direction is designated as the third position E3”, the pores 1h” are mainly present between the first position E1” and the second position E2” in such a way that the number of pores between the first position E1” and the second position E2” is greater than the number of pores between the second position E2” and the third position E3”. That is, in the resin film 10” with the conductor layer, the pores 1h” are mainly present near the conductor layer 2”.

[0141] The laminated substrate of the present invention is characterized by having a resin film with a conductor layer as described in the present invention.

[0142] Figure 7 This is a cross-sectional schematic diagram illustrating an example of a laminated substrate according to the present invention.

[0143] Figure 7The laminated substrate 50 shown has a resin film 10A with a conductor layer, a resin film 10B with a conductor layer, and a resin film 10C with a conductor layer in sequence in the stacking direction. That is, in the laminated substrate 50, the resin film 10A with a conductor layer, the resin film 10B with a conductor layer, and the resin film 10C with a conductor layer are stacked in sequence in the stacking direction.

[0144] The resin film 10A with a conductor layer has a resin film 1A and a conductor layer 2A.

[0145] The resin film 1A has a first main surface 1Aa and a second main surface 1Ab that are opposite each other in the thickness direction HD.

[0146] The conductor layer 2A is adjacent to the first main surface 1Aa side of the resin film 1A. In addition, the conductor layer 2A is also adjacent to the second main surface 1Bb side of the resin film 1B, which will be described later.

[0147] Resin film 1A contains thermoplastic resin.

[0148] The resin film 1A has pores 1Ah inside.

[0149] In the resin film 10A with a conductor layer, when the end face of the conductor layer 2A side, here designated as the first main surface 1Aa, is set as position EA1; the position in the lamination direction at a distance from position EA1 that is exactly one-third of the thickness of the resin film 1A is set as position EA2; and the position in the lamination direction facing the opposite side to position EA1, at a distance from position EA2 that is exactly one-third of the thickness of the resin film 1A, is set as position EA3, the voids 1Ah are primarily present between positions EA1 and EA2 such that the number of voids between positions EA1 and EA2 is greater than the number of voids between positions EA2 and EA3. That is, in the resin film 10A with a conductor layer, the voids 1Ah are primarily present near the conductor layer 2A.

[0150] The resin film 10B with a conductor layer has a resin film 1B, a conductor layer 2B, a conductor layer 2B' and a conductor layer 2B.

[0151] The resin film 1B has a first main surface 1Ba and a second main surface 1Bb that are opposite each other in the thickness direction HD.

[0152] Conductor layer 2B, conductor layer 2B', and conductor layer 2B” are adjacent to the first main surface 1Ba side of resin film 1B. In addition, conductor layer 2B, conductor layer 2B', and conductor layer 2B” are also adjacent to the second main surface 1Cb side of resin film 1C, which will be described later.

[0153] Resin film 1B contains thermoplastic resin.

[0154] The resin film 1B has pores 1Bh inside.

[0155] In the resin film 10B with a conductor layer, when the end face of the conductor layer 2B, conductor layer 2B', and conductor layer 2B'' (here, the first main surface 1Ba) is designated as position EB1, the position at which the distance from position EB1 in the lamination direction is exactly 1 / 3 of the thickness of the resin film 1B is designated as position EB2, and the position at which the distance from position EB2 in the lamination direction is exactly 1 / 3 of the thickness of the resin film 1B is designated as position EB3, the voids 1Bh are mainly present between positions EB1 and EB2 such that the number of voids between positions EB1 and EB2 is greater than the number of voids between positions EB2 and EB3. That is, in the resin film 10B with a conductor layer, the voids 1Bh are mainly present in the vicinity of conductor layers 2B, 2B', and 2B''.

[0156] In the resin film 10B with the conductor layer, such as Figure 7 As shown, when observing the cross-section along the stacking direction and the in-plane direction orthogonal to the stacking direction, the hole 1Bh preferably exists in such a way that the main surface (here, the lower surface) of the conductor layer 2B, conductor layer 2B' and conductor layer 2B” in the stacking direction surrounds the side surfaces (here, the left side and right side) of the conductor layer 2B, conductor layer 2B' and conductor layer 2B” in the in-plane direction.

[0157] The resin film 10C with a conductor layer has a resin film 1C and a conductor layer 2C.

[0158] The resin film 1C has a first principal surface 1Ca and a second principal surface 1Cb that are opposite each other in the thickness direction HD.

[0159] The conductor layer 2C is adjacent to the first main surface 1Ca side of the resin film 1C.

[0160] Resin film 1C contains thermoplastic resin.

[0161] The resin membrane 1C has pores 1Ch inside.

[0162] In the resin film 10C with a conductor layer, when the end face of the conductor layer 2C (here, the first main surface 1Ca) is designated as position 1 EC1, the position in the lamination direction at a distance from position 1 EC1 that is exactly 1 / 3 of the thickness of the resin film 1C is designated as position 2 EC2, and the position in the lamination direction facing the opposite side to position 1 EC1 at a distance from position 2 EC2 that is exactly 1 / 3 of the thickness of the resin film 1C is designated as position 3 EC3, the voids 1Ch are mainly present between positions 1 EC1 and 2 EC2 such that the number of voids between positions 1 EC1 and 2 EC2 is greater than the number of voids between positions 2 EC2 and 3 EC3. That is, in the resin film 10C with a conductor layer, the voids 1Ch are mainly present near the conductor layer 2C.

[0163] like Figure 7 As shown, conductor layer 2B is preferably disposed across the interface between resin film 1B and resin film 1C. Therefore, the interface between conductor layer 2B and resin film 1B, and the interface between conductor layer 2B and resin film 1C, are offset from the interface between resin film 1B and resin film 1C in the lamination direction, thus suppressing peeling at the interface between conductor layer 2B and resin film 1B and at the interface between conductor layer 2B and resin film 1C.

[0164] The conductor layer 2B' and conductor layer 2B" are preferably disposed across the interface between the resin film 1B and the resin film 1C, just like the conductor layer 2B.

[0165] It should be noted that, in Figure 7 The diagram shows the interface between resin film 1B and resin film 1C, but in reality, this interface may not be clearly visible. When the interface between resin film 1B and resin film 1C is not clearly visible, in... Figure 7 In the cross section along the stacking direction as shown, the surface passing through the center of the cross section of conductor layer 2B in the stacking direction and along the in-plane direction orthogonal to the stacking direction is regarded as the interface between resin film 1B and resin film 1C.

[0166] In the laminated substrate 50, the dielectric properties in the high-frequency region are improved because voids are provided inside the resin films 1A, 1B, and 1C. Furthermore, when the resin films 1A, 1B, and 1C are liquid crystal polymer films, the dielectric properties in the high-frequency region of the laminated substrate 50 are significantly improved in combination with the effects of the liquid crystal polymer.

[0167] As described above, in resin films 10A, 10B, and 10C with conductive layers, similarly to resin film 10 with conductive layers, voids are primarily present near the conductive layers. Therefore, when the conductive layer is a signal line for transmitting signals, in the laminated substrate 50 manufactured using resin films 10A, 10B, and 10C with conductive layers, similarly to the laminated substrate manufactured using resin film 10 with conductive layers, the dielectric constant near the signal line is reduced. Consequently, transmission loss in the high-frequency region is easily reduced, resulting in improved transmission characteristics in the high-frequency region.

[0168] In all of the resin films with conductive layers in resin films 10A, 10B, and 10C, when defining the first, second, and third positions as described above, it is preferable that the voids are primarily located between the first and second positions. However, it is also possible for the voids to be primarily located between the first and second positions in a portion of the resin films with conductive layers. That is, as long as the laminated substrate 50 has at least one resin film with a conductive layer in which a void is primarily located between the first and second positions, it may also have resin films with conductive layers in which voids are located other than between the first and second positions, or it may have resin films with conductive layers in which no voids are provided inside the resin film.

[0169] The preferred features of resin films 10A, 10B, and 10C with conductive layers are the same as those of resin film 10 with conductive layers described above. That is, the preferred features of resin films 1A, 1B, and 1C are the same as those of resin film 1 described above.

[0170] The thicknesses of resin films 1A, 1B, and 1C can be the same, different, or... Figure 7 The part shown is different.

[0171] As the constituent materials of conductor layer 2A, conductor layer 2B, conductor layer 2B', conductor layer 2B' and conductor layer 2C, examples include copper, silver, aluminum, stainless steel, nickel, gold, and alloys containing at least one of these metals, similar to the constituent materials of conductor layer 2.

[0172] Conductor layers 2A, 2B, 2B', 2B'', and 2C are formed, for example, from metal foil, similar to conductor layer 2, and preferably from copper foil. In this case, metals other than copper may also be present on the surface of the copper foil.

[0173] The constituent materials of conductor layer 2A, conductor layer 2B, conductor layer 2B', conductor layer 2B" and conductor layer 2C are preferably the same, but they may also be different from each other, or partially different.

[0174] The thicknesses of conductor layer 2A, conductor layer 2B, conductor layer 2B', conductor layer 2B" and conductor layer 2C can be as follows: Figure 7 They can be the same as each other, or they can be different from each other, or they can be partially different.

[0175] like Figure 7 As shown, the laminated substrate 50 preferably also has an interlayer connection conductor, which is arranged in such a way that it penetrates the resin film in the lamination direction but does not penetrate the conductor layer in the lamination direction but is connected to the conductor layer.

[0176] Figure 7 The laminated substrate 50 shown also has interlayer connection conductors 20A, 20B, 20C and 20D.

[0177] The interlayer connecting conductor 20A is arranged to penetrate the resin film 1B in the lamination direction but not in the conductor layer 2B', instead being connected to the conductor layer 2B'. More specifically, the interlayer connecting conductor 20A penetrates the resin film 1B in the lamination direction and is connected to the conductor layer 2B' on the first main surface 1Ba side of the resin film 1B. Furthermore, the interlayer connecting conductor 20A is connected to the conductor layer 2A on the second main surface 1Bb side of the resin film 1B. That is, the conductor layer 2A and the conductor layer 2B' are electrically connected via the interlayer connecting conductor 20A.

[0178] At the position where it is separated from the interlayer connecting conductor 20A, the interlayer connecting conductor 20B is arranged to penetrate the resin film 1B in the lamination direction but not penetrate the conductor layer 2B” in the lamination direction, instead being connected to the conductor layer 2B”. More specifically, at the position where it is separated from the interlayer connecting conductor 20A, the interlayer connecting conductor 20B penetrates the resin film 1B in the lamination direction and is connected to the conductor layer 2B” on the first main surface 1Ba side of the resin film 1B. In addition, at the position where it is separated from the interlayer connecting conductor 20A, the interlayer connecting conductor 20B is connected to the conductor layer 2A on the second main surface 1Bb side of the resin film 1B. That is, the conductor layer 2A and the conductor layer 2B” are electrically connected via the interlayer connecting conductor 20B.

[0179] The interlayer connecting conductor 20C is arranged to penetrate the resin film 1C in the lamination direction but not in the conductor layer 2C, instead being connected to the conductor layer 2C. More specifically, the interlayer connecting conductor 20C penetrates the resin film 1C in the lamination direction and is connected to the conductor layer 2C on the first main surface 1Ca side of the resin film 1C. Furthermore, the interlayer connecting conductor 20C is connected to the conductor layer 2B' on the second main surface 1Cb side of the resin film 1C. That is, the conductor layer 2B' and the conductor layer 2C are electrically connected via the interlayer connecting conductor 20C.

[0180] At the position where it is separated from the interlayer connecting conductor 20C, the interlayer connecting conductor 20D is arranged to penetrate the resin film 1C in the lamination direction but not in the conductor layer 2C, instead being connected to the conductor layer 2C. More specifically, at the position where it is separated from the interlayer connecting conductor 20C, the interlayer connecting conductor 20D penetrates the resin film 1C in the lamination direction and is connected to the conductor layer 2C on the first main surface 1Ca side of the resin film 1C. Furthermore, at the position where it is separated from the interlayer connecting conductor 20C, the interlayer connecting conductor 20D is connected to the conductor layer 2B” on the second main surface 1Cb side of the resin film 1C. That is, the conductor layer 2B” and the conductor layer 2C are electrically connected via the interlayer connecting conductor 20D.

[0181] Thus, in the laminated substrate 50, conductor layer 2A and conductor layer 2C are electrically connected via interlayer connection conductor 20A, conductor layer 2B', and interlayer connection conductor 20C. In addition, in the laminated substrate 50, conductor layer 2A and conductor layer 2C are also electrically connected via interlayer connection conductor 20B, conductor layer 2B'', and interlayer connection conductor 20D.

[0182] Interlayer connecting conductor 20A is formed, for example, by plating the inner wall of a through hole provided in such a way that it penetrates the resin film 1B in the thickness direction HD but does not penetrate the conductor layer 2B' in the thickness direction HD but reaches the conductor layer 2B', or by heat treatment after filling with conductive paste.

[0183] Interlayer connecting conductors 20B, 20C, and 20D are formed in the same way as interlayer connecting conductor 20A, except that they are formed in different locations.

[0184] When interlayer connection conductors 20A, 20B, 20C, and 20D are formed by plating, the metals constituting each interlayer connection conductor can be, for example, copper, tin, or silver, with copper being preferred.

[0185] When interlayer conductors 20A, 20B, 20C, and 20D are formed by heat treatment of a conductive paste, examples of metals included in each interlayer conductor include copper, tin, and silver. Preferably, each interlayer conductor includes copper, and more preferably, it includes both copper and tin. For example, when interlayer conductor 20A includes both copper and tin and conductor layer 2B' is formed from copper foil, interlayer conductor 20A and conductor layer 2B' undergo an alloying reaction at low temperature, thus facilitating conductivity between them. The same applies to other combinations of interlayer conductors and conductor layers.

[0186] When interlayer conductors 20A, 20B, 20C, and 20D are formed by heat treatment of a conductive paste, the resin contained in each interlayer conductor preferably comprises at least one thermosetting resin selected from epoxy resin, phenolic resin, polyimide resin, silicone resin or modified resin thereof, and acrylic resin, or at least one thermoplastic resin selected from polyamide resin, polystyrene resin, polymethyl methacrylate resin, polycarbonate resin, and cellulose resin.

[0187] The laminated substrate 50 is used, for example, as an electronic circuit substrate.

[0188] In the laminated substrate 50, the conductor layer 2B can be a signal line for transmitting signals. That is, the laminated substrate 50 can have the conductor layer 2B as a signal line for transmitting signals. In this case, the laminated substrate 50 constitutes a transmission line.

[0189] In the laminated substrate 50, when the conductor layer 2B is a signal line for transmitting signals, such as Figure 7 As shown, when observing the cross-section along the stacking direction and the in-plane direction orthogonal to the stacking direction, the aperture 1Bh preferably exists in such a way that it surrounds the main surface (here, the lower surface) of the conductor layer 2B in the stacking direction to the side surface (here, the left side and the right side) in the in-plane direction of the conductor layer 2B.

[0190] When conductor layer 2B is used as a signal line to transmit signals, the electric field tends to concentrate at the corners of conductor layer 2B. In contrast, if the via 1Bh exists in such a way that it surrounds the main surface of conductor layer 2B in the stacking direction to the side surface of conductor layer 2B in the in-plane direction, then the via 1Bh exists in such a way that it covers the corners of conductor layer 2B. Therefore, the transmission loss in the high-frequency region is easily reduced, resulting in an improvement in the transmission characteristics in the high-frequency region.

[0191] The laminated substrate 50 may have a conductor layer 2B as a signal line for transmitting signals, and conductor layers 2A and 2C as ground electrodes. In this case, the laminated substrate 50 constitutes a stripline transmission line.

[0192] When the stacked substrate 50 constitutes the above-mentioned transmission line, the conductor layer 2B can also be a signal line for transmitting high-frequency signals.

[0193] When the multilayer substrate 50 forms the transmission line, the via 1Bh is mainly located in the vicinity of the conductor layer 2B, i.e., the signal line, thus reducing the dielectric constant near the signal line. Therefore, when the multilayer substrate 50 forms the transmission line, the transmission loss in the high-frequency region is easily reduced, resulting in improved transmission characteristics in the high-frequency region.

[0194] The laminated substrate 50 is manufactured, for example, by the following method.

[0195] <Process for fabricating a resin film with a conductive layer>

[0196] Figure 8 , Figure 9 and Figure 10 This is a cross-sectional schematic diagram showing a process for fabricating a resin film with a conductor layer, as an example of a method for manufacturing a laminated substrate according to the present invention.

[0197] like Figure 8 As shown, a resin film 10A with a conductor layer is fabricated such that a conductor layer 2A is disposed adjacent to the first main surface 1Aa side of the resin film 1A.

[0198] The resin film 10A with the conductor layer is manufactured in the same manner as the resin film 10 with the conductor layer. Thus, in the resin film 10A with the conductor layer, the pores 1Ah are configured to exist primarily in the vicinity of the conductor layer 2A.

[0199] like Figure 9 As shown, a resin film 10B with conductor layers is fabricated such that conductor layers 2B, 2B', and 2B'' are disposed adjacent to the first main surface 1Ba side of the resin film 1B.

[0200] The resin film 10B with the conductor layer is manufactured in the same manner as the resin film 10 with the conductor layer. Thus, in the resin film 10B with the conductor layer, the pores 1Bh are arranged to be present primarily in the vicinity of the conductor layers 2B, 2B', and 2B''.

[0201] When fabricating the resin film 10B with the conductor layer, for example, after the conductor layer is pressed onto the first main surface 1Ba of the resin film 1B, the conductor layer is etched, thereby patterning the conductor layer 2B, conductor layer 2B', and conductor layer 2B''. Alternatively, the conductor layer 2B, conductor layer 2B', and conductor layer 2B''' are prepared in advance, and each conductor layer is pressed onto the first main surface 1Ba of the resin film 1B.

[0202] like Figure 10As shown, a resin film 10C with a conductor layer is fabricated such that a conductor layer 2C is disposed adjacent to the first main surface 1Ca side of the resin film 1C.

[0203] The resin film 10C with the conductor layer is manufactured in the same manner as the resin film 10 with the conductor layer. Thus, in the resin film 10C with the conductor layer, the pores 1Ch are arranged to be present primarily in the vicinity of the conductor layer 2C.

[0204] <Process for forming through holes>

[0205] Figure 11 and Figure 12 This is a cross-sectional schematic diagram showing a process for forming through holes, as an example of a method for manufacturing a laminated substrate according to the present invention.

[0206] like Figure 11 As shown, for the resin film 10B with the conductor layer, a through-hole 21A is formed such that it penetrates the resin film 1B in the thickness direction HD but does not penetrate the conductor layer 2B' in the thickness direction HD, but reaches the conductor layer 2B'. As a result, a portion of the conductor layer 2B' is exposed from the through-hole 21A.

[0207] Furthermore, for the resin film 10B with the conductor layer, at a position separate from where the through-hole 21A is to be formed, the through-hole 21B is formed in such a way that it penetrates the resin film 1B in the thickness direction HD but does not penetrate the conductor layer 2B” in the thickness direction HD, but reaches the conductor layer 2B”. As a result, a portion of the conductor layer 2B” is exposed from the through-hole 21B.

[0208] Through the above operations, through holes 21A and 21B are formed in the resin film 10B with the conductor layer. At this time, through holes 21A and 21B can be formed at the same time or at different times.

[0209] like Figure 12 As shown, for the resin film 10C with the conductor layer, a through-hole 21C is formed in such a way that it penetrates the resin film 1C in the thickness direction HD but does not penetrate the conductor layer 2C in the thickness direction HD, but reaches the conductor layer 2C. As a result, a portion of the conductor layer 2C is exposed from the through-hole 21C.

[0210] Furthermore, for the resin film 10C with the conductor layer, at a location separate from where the via 21C is to be formed, the via 21D is formed such that it penetrates the resin film 1C in the thickness direction HD but does not penetrate the conductor layer 2C in the thickness direction HD, but reaches the conductor layer 2C. As a result, a portion of the conductor layer 2C is exposed from the via 21D.

[0211] Through the above operations, through holes 21C and 21D are formed in the resin film 10C with the conductor layer. At this time, through holes 21C and 21D can be formed at the same time or at different times.

[0212] When forming through holes 21A, 21B, 21C and 21D, it is preferable to irradiate the resin film with the conductor layer from the resin film side.

[0213] <Process of filling conductive paste>

[0214] Figure 13 and Figure 14 This is a cross-sectional schematic diagram showing a step of filling a conductive paste, which is an example of a method for manufacturing a laminated substrate according to the present invention.

[0215] like Figure 13 As shown, for the resin film 10B with a conductor layer, conductive paste 22A is filled into the through-hole 21A. Additionally, for the resin film 10B with a conductor layer, conductive paste 22B is filled into the through-hole 21B. In this case, conductive paste 22A and conductive paste 22B can be filled at the same time, or they can be filled at different times.

[0216] like Figure 14 As shown, for the resin film 10C with a conductor layer, conductive paste 22C is filled into the through-hole 21C. Additionally, for the resin film 10C with a conductor layer, conductive paste 22D is filled into the through-hole 21D. At this time, conductive paste 22C and conductive paste 22D can be filled at the same time, or they can be filled at different times.

[0217] Methods for filling conductive pastes 22A, 22B, 22C, and 22D include, for example, screen printing and vacuum filling.

[0218] Conductive paste 22A, conductive paste 22B, conductive paste 22C and conductive paste 22D, for example, contain metal and resin respectively.

[0219] Metals contained in each of the conductive pastes 22A, 22B, 22C, and 22D include, for example, copper, tin, and silver. Preferably, each conductive paste contains copper, and more preferably, it contains both copper and tin.

[0220] The resin contained in each of the conductive pastes 22A, 22B, 22C and 22D preferably comprises at least one thermosetting resin selected from epoxy resin, phenolic resin, polyimide resin, silicone resin or modified resin thereof, and acrylic resin, or at least one thermoplastic resin selected from polyamide resin, polystyrene resin, polymethyl methacrylate resin, polycarbonate resin and cellulose resin.

[0221] Conductive pastes 22A, 22B, 22C, and 22D may also contain media, solvents, thixotropic agents, activators, etc.

[0222] Examples of mediators include rosin-based resins composed of rosin and derivatives such as modified rosin, synthetic resins composed of rosin and derivatives such as modified rosin, or mixtures of these resins.

[0223] Rosin-based resins, which are composed of rosin and its derivatives such as modified rosin, include, for example, rosin resin, oil rosin, wood rosin, polymerized rosin, hydrogenated rosin, formylated rosin, rosin esters, rosin-modified maleic acid resin, rosin-modified phenolic resin, rosin-modified alkyd resin, and various other rosin derivatives.

[0224] Synthetic resins composed of rosin and its derivatives, such as modified rosin, include, for example, polyester resins, polyamide resins, phenoxy resins, and terpene resins.

[0225] Examples of solvents include alcohols, ketones, esters, ethers, aromatic compounds, and hydrocarbons. Specific examples include benzyl alcohol, ethanol, isopropanol, butanol, diethylene glycol, ethylene glycol, glycerol, ethyl cellosolve, butyl cellosolve, ethyl acetate, butyl acetate, butyl benzoate, diethyl adipate, dodecane, tetradecene, α-terpineol, terpineol, 2-methyl-2,4-pentanediol, 2-ethylhexanediol, toluene, xylene, propylene glycol monophenyl ether, diethylene glycol monohexyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diisobutyl adipate, hexanediol, cyclohexanediol, 2-terpineyloxyethanol, 2-dihydroterpineyloxyethanol, and mixtures thereof. Among these, terpineol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, or diethylene glycol monoethyl ether are preferred.

[0226] Examples of thixotropic agents include hydrogenated castor oil, carnauba wax, amides, hydroxy fatty acids, dibenzyl sorbitol, bis(p-methylbenzyl)sorbitol, beeswax, stearamide, and hydroxystearic acid ethylenediamide (HID). Furthermore, these thixotropic agents can be supplemented with fatty acids such as caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, hydroxy fatty acids such as 1,2-hydroxystearic acid, antioxidants, surfactants, and amines, as needed.

[0227] Examples of active agents include amine hydrohalides, organic halogen compounds, organic acids, organic amines, and polyols.

[0228] Examples of amine hydrohalides include diphenylguanidine hydrobromide, diphenylguanidine hydrochloride, cyclohexylamine hydrobromide, ethylamine hydrochloride, ethylamine hydrobromide, diethylaniline hydrobromide, diethylaniline hydrochloride, triethanolamine hydrobromide, and monoethanolamine hydrobromide.

[0229] Examples of organohalogen compounds include chlorinated paraffin, tetrabromoethane, dibromopropanol, 2,3-dibromo-1,4-butanediol, 2,3-dibromo-2-butene-1,4-diol, and tris(2,3-dibromopropyl)isocyanurate.

[0230] Examples of organic acids include malonic acid, fumaric acid, glycolic acid, citric acid, malic acid, succinic acid, phenylsuccinic acid, maleic acid, salicylic acid, anthranilic acid, glutaric acid, octanoic acid, adipic acid, sebacic acid, stearic acid, rosin acid, benzoic acid, trimellitic acid, pyromellitic acid, and dodecanoic acid.

[0231] Examples of organic amines include monoethanolamine, diethanolamine, triethanolamine, tributylamine, aniline, and diethylaniline.

[0232] Examples of polyols include erythritol, pyrogallol, and ribitol.

[0233] <Process for forming interlayer conductors>

[0234] Figure 15 This is a cross-sectional schematic diagram showing a step in forming interlayer interconnect conductors, as an example of a method for manufacturing a multilayer substrate according to the present invention.

[0235] like Figure 15As shown, a resin film 10A with a conductive layer, a resin film 10B with a conductive layer filled with conductive paste 22A and conductive paste 22B, and a resin film 10C with a conductive layer filled with conductive paste 22C and conductive paste 22D are sequentially stacked in the stacking direction. At this time, the surface (upper surface) of the conductive layer 2A side of the resin film 10A is in contact with the surface (lower surface) of the resin film 1B side of the resin film 10B, and the surface (upper surface) of the conductive layer 2B side (conductor layer 2B' side, conductor layer 2B" side) of the resin film 10B is in contact with the surface (lower surface) of the resin film 1C side of the resin film 10C. It should be noted that... Figure 15 In the illustration, the individual resin films with conductor layers are shown separately from each other.

[0236] Then, the resulting laminate is heated while pressure is applied in the lamination direction to perform hot pressing. As a result, resin film 10A with a conductor layer is pressed together with resin film 10B with a conductor layer, and resin film 10B with a conductor layer is pressed together with resin film 10C with a conductor layer.

[0237] Here, when the resin film 10B with the conductor layer and the resin film 10C with the conductor layer are pressed together, since the resin film 1B contains thermoplastic resin, the conductor layer 2B, conductor layer 2B', and conductor layer 2B" are pressed into the resin film 1B. As a result, the hole 1Bh also moves together with the conductor layer 2B, conductor layer 2B', and conductor layer 2B" and thus the hole 1Bh exists in such a way that it surrounds the main surface of the conductor layer 2B, conductor layer 2B', and conductor layer 2B" in the stacking direction to the side surface of the conductor layer 2B, conductor layer 2B" and conductor layer 2B" in the in-plane direction. Thus, the configuration in which the pore 1Bh exists in a manner that surrounds the main surface of the conductor layer 2B, conductor layer 2B' and conductor layer 2B" in the stacking direction to the side surface of the conductor layer 2B, conductor layer 2B' and conductor layer 2B" in the in-plane direction is achieved by using a method of stacking a resin film 10B with a conductor layer in which the pore 1Bh is provided inside the resin film 1B containing thermoplastic resin. More specifically, it is achieved by stacking the resin film 10B with a conductor layer together with a resin film 10C with a conductor layer.

[0238] Furthermore, conductive pastes 22A, 22B, 22C, and 22D are cured during hot pressing to become interlayer connection conductors 20A, 20B, 20C, and 20D, respectively. Thus, interlayer connection conductors 20A, 20B, 20C, and 20D are formed in the through-holes 21D of through-holes 21A, 21B, and 21C, respectively.

[0239] When forming interlayer connection conductors 20A, 20B, 20C, and 20D, it is also possible to avoid filling the through-holes with conductive paste and instead use metals such as copper, tin, and silver to plate the inner walls of the through-holes.

[0240] Therefore, manufacturing Figure 7 The laminated substrate 50 shown.

[0241] The laminated substrate of the present invention may further have side conductors on the sides along the lamination direction.

[0242] Figure 16 This refers to an example of a laminated substrate used in this invention, and... Figure 7 Cross-sectional diagrams of different examples.

[0243] Figure 16 The laminated substrate 50' shown, except for Figure 7 In addition to the configuration of the laminated substrate 50 shown, it also has a side conductor 30 on the side along the lamination direction.

[0244] The side conductor 30 can function as a shielding electrode to shield electromagnetic waves. Therefore, by having the side conductor 30, the electromagnetic wave shielding of the sides of the laminated substrate 50' is easily improved.

[0245] The side conductor 30 is preferably connected to the conductor layer. Figure 16 In the stacked substrate 50' shown, the side conductor 30 is connected to conductor layers 2A, 2B', 2B'', and 2C. Thus, as described above, when conductor layers 2A and 2C function as ground electrodes, the side conductor 30 functions as a shielding electrode and also as a ground electrode.

[0246] Materials used to construct the side conductor 30 include, for example, copper, tin, and silver.

[0247] The side conductor 30 is formed by plating the side of the resin film laminate with the conductor layer using metals such as copper, tin, and silver through sputtering.

[0248] In addition to the side conductors 30, the laminated substrate 50' also has interlayer connection conductors 20A, 20B, 20C and 20D, but may not have these interlayer connection conductors.

[0249] The laminated substrate of the present invention can be as follows: Figure 7 The stacked substrate 50 shown and Figure 16 The laminated substrate 50' shown has three resin films with conductor layers, or it may have only one resin film with a conductor layer.

[0250] Figure 17 This refers to an example of a laminated substrate used in this invention, and... Figure 7 and Figure 16 Cross-sectional diagrams of different examples.

[0251] Figure 17 The laminated substrate 50A shown has in the lamination direction Figure 5 The resin film 10' and resin film 1' with conductor layers are shown.

[0252] The resin film 1' is in contact with the surface (upper surface) of the resin film 10' with conductor layer 2' side, which includes a portion of the first main surface 1a of the resin film 1.

[0253] In the laminated substrate 50A, such as Figure 17 As shown, when observing the cross-section along the stacking direction and the in-plane direction orthogonal to the stacking direction, the aperture 1h preferably exists in such a way that it surrounds the main surface (here, the lower surface) of the conductor layer 2' in the stacking direction to the side surface (here, the left side and the right side) of the conductor layer 2' in the in-plane direction.

[0254] Figure 18 This refers to an example of a laminated substrate used in this invention, and... Figure 7 , Figure 16 and Figure 17 Cross-sectional diagrams of different examples.

[0255] Figure 18 The laminated substrate 50A' shown has in the lamination direction Figure 5 The resin film 10' with a conductor layer shown is a resin film 1 that is different from the resin film 1 with a conductor layer 10'.

[0256] Two resin films 1 are stacked in the stacking direction such that their respective first main surfaces 1a are in contact with each other.

[0257] In the laminated substrate 50A', such as Figure 18 As shown, when observing the cross-section along the stacking direction and the in-plane direction orthogonal to the stacking direction, the void 1h preferably exists in such a way that it surrounds the side surface (here, the lower surface) and the other main surface (here, the upper surface) of the conductor layer 2' in the stacking direction to the side surface (here, the left side and the right side) in the in-plane direction of the conductor layer 2'.

[0258] The laminated substrate 50A' is manufactured as follows: First, two resin films 10' with conductor layers are prepared. Next, for one resin film 10' with a conductor layer, the conductor layer 2' is etched to remove the resin film 1. Then, the resin film 1 removed from one resin film 10' with a conductor layer is laminated with another resin film 10' with a conductor layer in the lamination direction such that the first main surface 1a of each resin film 1 is in contact with each other, thereby manufacturing the laminated substrate 50A'.

[0259] It should be noted that in the above-described manufacturing method of the laminated substrate 50A', when preparing a resin film 1 with holes 1h for laminating on a resin film 10' with a conductor layer, the resin film 1 is removed by etching the conductor layer 2' onto the resin film 10' with the conductor layer. However, it is also possible to use only the resin film 1 with holes 1h.

[0260] In the laminated substrate 50A' manufactured as described above, such as Figure 18 As shown, the pore 1h exists in such a way that it surrounds the first main surface 1a of each resin film 1 and the two main surfaces (the lower surface and the upper surface in this case) of the conductor layer 2' in the stacking direction to the side surface (the left side and the right side in this case) of the conductor layer 2' in the in-plane direction.

[0261] The laminated substrate of the present invention may also have two resin films with conductor layers.

[0262] Figure 19 This refers to an example of a laminated substrate used in this invention, and... Figure 7 , Figure 16 , Figure 17 and Figure 18 Cross-sectional diagrams of different examples.

[0263] Figure 19 The laminated substrate 50B shown has two in the lamination direction. Figure 1 The resin film 10 with a conductor layer is shown.

[0264] Two resin films 10 with conductive layers are stacked in the stacking direction such that the second main surface 1b of each resin film 1 is in contact with each other.

[0265] The above examples illustrate the case where the laminated substrate of the present invention has only one resin film with a conductor layer, two resin films with conductor layers, and three resin films with conductor layers. However, the laminated substrate of the present invention may also have four or more resin films with conductor layers.

[0266] In the laminated substrate of the present invention, the resin film can undergo plastic deformation. In the laminated substrate of the present invention, the resin film, since it contains a thermoplastic resin, can be plastically deformed, for example, by heat.

[0267] In the laminated substrate of the present invention, when the resin film undergoes plastic deformation, the resin film and the conductor layer can be bent as a single unit. In conventional laminated substrates such as the multilayer wiring substrate described in Patent Document 1, where voids are provided inside the resin film, if the resin film and the conductor layer are bent as a single unit, the voids may become sources of cracks. In contrast, in the laminated substrate of the present invention, the voids are mainly located near the conductor layer, so even if the resin film and the conductor layer are bent as a single unit, the voids are less likely to become sources of cracks.

[0268] Example

[0269] The following provides more specific embodiments of the resin film with a conductor layer according to the present invention. It should be noted that the present invention is not limited to the following embodiments.

[0270] As thermoplastic resins, the following liquid crystal polymers A, B, C, and D are prepared.

[0271] <Liquid Crystal Polymer A>

[0272] As liquid crystal polymer A, a type II fully aromatic polyester is prepared as a copolymer of 75 mol% 6-hydroxy-2-naphthoic acid and 25 mol% p-hydroxybenzoic acid, with a melting point of 320°C and a melt viscosity of 111 Pa·s.

[0273] <Liquid Crystal Polymer B>

[0274] As liquid crystal polymer B, a type II fully aromatic polyester is prepared as a copolymer of 75 mol% 6-hydroxy-2-naphthoic acid and 25 mol% p-hydroxybenzoic acid, with a melting point of 320°C and a melt viscosity of 74 Pa·s.

[0275] <Liquid Crystal Polymer C>

[0276] As liquid crystal polymer C, a type II fully aromatic polyester is prepared as a copolymer of 20 mol% 6-hydroxy-2-naphthoic acid and 80 mol% p-hydroxybenzoic acid, with a melting point of 325°C and a melt viscosity of 98 Pa·s.

[0277] <Liquid Crystal Polymer D>

[0278] As liquid crystal polymer D, a type II fully aromatic polyester is prepared as a copolymer of 75 mol% 6-hydroxy-2-naphthoic acid and 25 mol% p-hydroxybenzoic acid, with a melting point of 320°C and a melt viscosity of 79 Pa·s.

[0279] The melt viscosities of liquid crystal polymers A, B, C, and D are determined at a temperature of 330°C and a shear rate of 1000 s.-1 It was measured under the conditions specified.

[0280] [Example 1]

[0281] The liquid crystal polymer film with a conductor layer of Example 1 was manufactured using the following method.

[0282] <Processes for creating laminated structures>

[0283] First, a liquid crystal polymer film was prepared using a resin material containing a liquid crystal polymer in the proportions shown in Table 1, and by the aforementioned known film-forming method.

[0284] For one main surface of the liquid crystal polymer film, a rough surface with unevenness is provided. For one main surface of the liquid crystal polymer film that subsequently becomes the side on which the conductor layer is provided, the arithmetic mean height Sa is measured using the above method with a non-contact laser microscope. The results are shown in Table 1.

[0285] In addition, copper foil "WS" manufactured by Furukawa Electric Corporation is prepared as the conductor layer.

[0286] Then, by pressing a conductor layer onto one of the main surfaces of the liquid crystal polymer film, a laminate having a liquid crystal polymer film and a conductor layer in the lamination direction was fabricated. In the laminate, one of the main surfaces of the liquid crystal polymer film is a rough surface, thus creating a space in the in-plane direction between the liquid crystal polymer film and the conductor layer.

[0287] <Process for setting up holes>

[0288] By heat-treating the laminate, a liquid crystal polymer film with a conductor layer as described in Example 1 was manufactured, which has pores inside the liquid crystal polymer film.

[0289] [Examples 2-7 and Comparative Example 1]

[0290] Liquid crystal polymer films were prepared using resin materials in which liquid crystal polymers were mixed in the proportions shown in Table 1. Otherwise, liquid crystal polymer films with conductive layers of Examples 2-7 and Comparative Example 1 were prepared in the same manner as the liquid crystal polymer film with conductive layer of Example 1.

[0291] In Table 1, liquid crystal polymers A, B, C, and D are represented as “A”, “B”, “C”, and “D”, respectively.

[0292] [evaluate]

[0293] The liquid crystal polymer films with conductor layers of Examples 1-7 and Comparative Example 1 were evaluated as follows. The results are shown in Table 1.

[0294] < 13 C-NMR spectrum>

[0295] First, for the liquid crystal polymer film with a conductor layer, the conductor layer is etched to remove the liquid crystal polymer film.

[0296] Next, 5g of the liquid crystal polymer film and 200cc of methanol were placed in a high-temperature, high-pressure reactor (HTPR) "MMJ-500" manufactured by OM Lab Tech. The system was then replaced with argon and heated at 280°C for 15 minutes to obtain a solution containing the liquid crystal polymer film. During this process, the methanol vaporized upon heating, reaching the critical pressure of methanol, thus placing the methanol in a supercritical state. The solution was then vacuum-dried to remove the solvent, yielding a powder of the liquid crystal polymer film decomposed by supercritical methanol. 0.014g of this powder was then dissolved in 0.7ml of deuterated methanol to obtain a sample for NMR analysis.

[0297] Next, for the samples used in NMR measurements, NMR measurements were performed using a JNM-ECP600 Fourier transform nuclear magnetic resonance (FMR) instrument manufactured by NJE Ltd., thereby obtaining... 13 C-NMR spectrum. Then, based on 13 The integrated values ​​of the peaks from the benzene ring, the naphthalene ring, and the carboxymethyl group were obtained from the C-NMR spectra and denoted as CA, CB, and CC, respectively.

[0298] Here, peaks originating from the benzene ring, and more specifically from methyl p-hydroxybenzoate, are defined as peaks with a chemical shift of 113 ppm or higher and 115 ppm or lower (114 ± 1 ppm). Peaks originating from the naphthalene ring, and more specifically from methyl 6-hydroxy-2-naphthoate, are defined as peaks with a chemical shift of 107 ppm or higher and 109 ppm or lower (108 ± 1 ppm). Peaks originating from the carboxymethyl group, and more specifically from the methyl group of the ester, are defined as peaks with a chemical shift of 49 ppm or higher and 51 ppm or lower (50 ± 1 ppm).

[0299] Calculate (CA+CB) / CC based on CA, CB, and CC obtained above.

[0300] <Viscoelastic Properties>

[0301] First, for the liquid crystal polymer film with a conductor layer, the conductor layer is etched to remove the liquid crystal polymer film. Next, using a dynamic viscoelasticity measuring apparatus "RSA-G2" manufactured by TA Instruments, the temperature dependence of the loss tangent of the liquid crystal polymer film is measured under the following conditions: dynamic strain is set to 0.25%, frequency is set to 0.5 Hz, heating rate is set to 10 °C / min, and the measurement temperature range is set from 40 °C to the melting point of the liquid crystal polymer contained in the liquid crystal polymer film. A graph showing the relationship between the loss tangent of the liquid crystal polymer film and temperature is then obtained. Finally, the graph showing the relationship between the loss tangent of the liquid crystal polymer film and temperature is integrated over the temperature range from 40 °C to the melting point of the thermoplastic resin contained in the liquid crystal polymer film to obtain the integral value of the loss tangent.

[0302] The melting point of the thermoplastic resin contained in the liquid crystal polymer film was determined as follows. First, the liquid crystal polymer film was heated to complete melting at a heating rate of 20°C / min using a differential scanning calorimeter (DSC7000X) manufactured by Hitachi High-Tech Science. Next, the resulting melt was cooled to 175°C at a cooling rate of 20°C / min, and then heated again at a heating rate of 20°C / min. The temperature corresponding to the endothermic peak observed during this heating process was then determined as the melting point of the thermoplastic resin contained in the liquid crystal polymer film. It should be noted that when the endothermic peak is difficult to observe using the above method, the melting point of the thermoplastic resin contained in the liquid crystal polymer film was determined by textural observation under orthogonal Nicol conditions using a polarizing microscope.

[0303] <Position location>

[0304] For the region where the liquid crystal polymer film with the conductor layer overlaps with the conductor layer, scanning electron microscopy was used to capture cross-sectional images along the stacking direction when viewed in-plane. These cross-sectional images were captured at 5 to 10 different locations in the in-plane direction. Then, image analysis software was used to analyze all the captured cross-sectional images. Based on this, the positions of all voids in the liquid crystal polymer film were identified as follows: the position of the conductor layer side end face was designated as position 1; the position in the stacking direction at a distance exactly 1 / 3 of the thickness of the liquid crystal polymer film from position 1 was designated as position 2; and the position in the stacking direction facing the opposite side to position 1, at a distance exactly 1 / 3 of the thickness of the liquid crystal polymer film from position 2, was designated as position 3. The determination criteria are as follows.

[0305] ○(Good): The void exists between position 1 and position 2.

[0306] × (Defect): The void does not exist between position 1 and position 2, but exists between position 2 and position 3, or the void does not exist.

[0307] <number of holes>

[0308] For liquid crystal polymer films with a conductor layer, the presence of voids is pre-confirmed by observing the area along the thickness direction. Based on this, a cross-sectional image along the thickness direction is captured using a scanning electron microscope, showing the region between positions 1 and 2 viewed in-plane. Cross-sectional images of the region between positions 1 and 2 in the liquid crystal polymer film are captured at 5 to 10 different locations in the in-plane direction. The size of each cross-sectional image is set to 75 μm x 125 μm (e.g., the field of view size when viewed at 1000x magnification). Then, image analysis software is used to analyze all captured cross-sectional images, counting the total number of voids in all cross-sectional images. The average value of each cross-sectional image (one field of view) calculated based on the total number of voids is determined as the number of voids between positions 1 and 2.

[0309] The number of voids between the second and third positions is determined in the same way as the number of voids between the first and second positions. It should be noted that in all cross-sectional images (5 to 10 cross-sectional images) taken of the area between the second and third positions of the liquid crystal polymer film, if the existence of voids cannot be confirmed, the number of voids between the second and third positions is set to 0.

[0310] <hole diameter>

[0311] For liquid crystal polymer films with a conductor layer, the presence of voids is pre-confirmed by observing the area along the thickness direction. Based on this, a cross-sectional image along the thickness direction is captured using a scanning electron microscope, showing the region between positions 1 and 2 viewed in-plane. Cross-sectional images of the region between positions 1 and 2 in the liquid crystal polymer film are captured at 5 to 10 different locations in the in-plane direction. The size of each cross-sectional image is set to 75 μm x 125 μm (e.g., the field of view size when viewed at 1000x magnification). Then, image analysis software is used to analyze all captured cross-sectional images, thereby determining the equivalent circle diameter of all voids in all cross-sectional images. The maximum value among the obtained measurements is determined as the void diameter existing between positions 1 and 2.

[0312] <Porosity>

[0313] For a liquid crystal polymer film with a conductor layer, an in-plane image of the main surface with the conductor layer disposed thereon is taken at 100x magnification using an optical microscope. The image is then analyzed using image analysis software to determine the area ratio of voids in a 10mm square region within the image. The obtained value is defined as the porosity between positions 1 and 2.

[0314] [Table 1]

[0315]

[0316] As shown in Table 1, in the liquid crystal polymer films with conductor layers in Examples 1 to 7, the voids are mainly located between the first and second positions, resulting in the voids being mainly located near the conductor layer.

[0317] In the liquid crystal polymer films with conductor layers in Examples 1-7, the reason why the voids are located near the conductor layer can be attributed to the fact that a liquid crystal polymer film with a loss tangent of viscoelastic properties of 29.7 or less was used when manufacturing the liquid crystal polymer films with conductor layers in Examples 1-7. That is, a liquid crystal polymer film with a low viscous component and low loss tangent of viscoelastic properties was used, which is not easily softened even at high temperatures. It can be considered that, in the manufacturing of the liquid crystal polymer films with conductor layers in Examples 1-7, since a liquid crystal polymer film with this characteristic was used, even if the laminate is heat-treated, the gas contained in the space starting from the unevenness of one main surface of the liquid crystal polymer film is difficult to be discharged to the outside of the liquid crystal polymer film during the process of setting the voids. As a result, it can be considered that in the liquid crystal polymer films with conductor layers in Examples 1-7, the gas contained in the space can easily enter the interior of the liquid crystal polymer film, and therefore it is easy to set voids inside the liquid crystal polymer film, more specifically, near the conductor layer.

[0318] Compared to the liquid crystal polymer films with conductor layers in Examples 2 and 3, the liquid crystal polymer films with conductor layers in Examples 4-7 have a higher number of voids and a higher porosity between the first and second positions. This can be attributed to the fact that, in manufacturing the liquid crystal polymer films with conductor layers in Examples 4-7, a liquid crystal polymer film with an arithmetic mean height Sa of the main surface on the side where the conductor layer is provided was used, which is 240 nm or more.

[0319] On the other hand, in the liquid crystal polymer film with a conductor layer in Comparative Example 1, there are no pores inside the liquid crystal polymer film.

[0320] In the liquid crystal polymer film with a conductor layer in Comparative Example 1, the reason why no pores were provided inside the liquid crystal polymer film can be attributed to the fact that a liquid crystal polymer film with a loss tangent of viscoelastic properties of Comparative Example 1 was used during its manufacture. This means that a liquid crystal polymer film with a high viscous component and a loss tangent of viscoelastic properties was used, which is prone to softening at high temperatures. It can be argued that because a liquid crystal polymer film with this characteristic was used during the manufacture of the liquid crystal polymer film with a conductor layer in Comparative Example 1, if the laminate is heat-treated during the process of providing the aforementioned pores, it is difficult to maintain the uneven shape of one main surface of the liquid crystal polymer film. Gas contained in the space originating from this unevenness can easily escape to the outside of the liquid crystal polymer film. Therefore, it can be argued that in the liquid crystal polymer film with a conductor layer in Comparative Example 1, gas contained in the space is difficult to enter the interior of the liquid crystal polymer film, and thus no pores were provided inside the liquid crystal polymer film.

[0321] Explanation of reference numerals in the attached figures

[0322] 1, 1', 1”, 1A, 1B, 1C Resin film

[0323] The first principal surface of the resin film: 1a, 1a", 1Aa, 1Ba, 1Ca

[0324] 1b, 1b", 1Ab, 1Bb, 1Cb The second principal surface of the resin film

[0325] 1h, 1h”, 1Ah, 1Bh, 1Ch empty holes

[0326] 2, 2', 2”, 2A, 2B, 2B', 2B”, 2C Conductor layers

[0327] 10, 10', 10”, 10A, 10B, 10C Resin films with conductor layers

[0328] 15-layer stack

[0329] 15h space

[0330] 20A, 20B, 20C, 20D Interlayer Connector

[0331] Through holes 21A, 21B, 21C, and 21D

[0332] 22A, 22B, 22C, 22D Conductive paste

[0333] 30 Side conductor

[0334] 50, 50', 50A, 50A', 50B laminated substrates

[0335] E1, E1”, EA1, EB1, EC1 Position 1

[0336] E2, E2”, EA2, EB2, EC2 Second position

[0337] E3, E3”, EA3, EB3, EC3 (3rd position)

[0338] HD Thickness Direction

[0339] MD First Direction

[0340] TD, direction 2.

Claims

1. A resin film with a conductive layer, characterized in that, It has a resin film and a conductor layer in the stacking direction. The resin film comprises thermoplastic resin and has pores inside. The conductor layer is adjacent to at least one main surface side of the resin film. In the resin film, when the position of the end face on the conductor layer side is designated as the first position, the position in the lamination direction that is exactly 1 / 3 of the thickness of the resin film is designated as the second position, and the position in the lamination direction that is exactly 1 / 3 of the thickness of the resin film is designated as the third position, the position in the lamination direction that is opposite to the first position and is located at a distance from the second position that is exactly 1 / 3 of the thickness of the resin film, The voids are primarily located between the first and second positions, with the number of voids between the first and second positions exceeding the number between the second and third positions. There is no actual void between the second position and the third position. In the viscoelastic properties representing the relationship between the loss tangent of the resin film and temperature, the integral value of the loss tangent over the temperature range from 40°C to the melting point of the thermoplastic resin contained in the resin film is 29.7 or less. The thermoplastic resin is a fully aromatic polyester liquid crystal polymer.

2. The resin film with a conductor layer according to claim 1, wherein, For the resin membrane, in the state after decomposition with supercritical methanol... 13 When the integral value of the peak from the benzene ring in the C-NMR spectrum is set as CA, the integral value of the peak from the naphthalene ring is set as CB, and the integral value of the peak from the carboxymethyl group is set as CC, the ratio (CA+CB) / CC is greater than 1.25 and less than 1.

65.

3. The resin film with a conductor layer according to claim 1 or 2, wherein, The diameter of the pore existing between the first position and the second position is less than 20 μm.

4. A laminated substrate, characterized in that, A resin film having a conductor layer as described in any one of claims 1 to 3.

5. The laminated substrate according to claim 4, wherein, The conductor layer is the signal line for transmitting signals. When observing a cross-section along the stacking direction and in the in-plane direction orthogonal to the stacking direction, the aperture exists in such a manner that it surrounds the main surface of the conductor layer in the stacking direction to the side surface of the conductor layer in the in-plane direction.

6. The laminated substrate according to claim 4 or 5, wherein, The resin film underwent plastic deformation.

7. The laminated substrate according to claim 6, wherein, The resin film and the conductor layer are bent together as a whole.

8. A method for manufacturing a resin film with a conductor layer according to any one of claims 1 to 3, characterized in that, It has the following processes: A process of fabricating a laminate by providing a conductor layer adjacent to at least one main surface side of a resin film comprising a thermoplastic resin, wherein the laminate has the resin film and the conductor layer in a lamination direction; and The process of creating pores inside the resin film by heat treating the laminate is described. The at least one main surface is a rough surface with unevenness. In the process of setting the voids, in the resin film, when the position of the end face on the conductor layer side is set as the first position, the position at which the distance from the first position in the stacking direction is exactly 1 / 3 of the thickness of the resin film is set as the second position, and the position at which the distance from the second position in the stacking direction is exactly 1 / 3 of the thickness of the resin film is set as the third position, the voids that are mainly present between the first position and the second position are set in such a way that the number of voids between the first position and the second position is greater than the number of voids between the second position and the third position.

9. The method for manufacturing a resin film with a conductor layer according to claim 8, wherein, In the process of fabricating the laminate, the arithmetic mean height Sa of the main surface of the resin film on the side where the conductor layer is disposed is 240 nm or more.

Images