JP2020116830A - Low dielectric substrate material and manufacturing method therefor - Google Patents

Abstract

To provide a low dielectric substrate material that can achieve the uniform thickness of a porous resin layer and a method of manufacturing the same.SOLUTION: A low dielectric substrate material 1 comprises: a metal layer 2; a porous resin layer 3 that is disposed on one thickness-direction surface of the metal layer 2; and a spacer layer 4 that is disposed on the one surface of the metal layer 2 so as to be adjacent to the porous resin layer 3, and that is thinner than the porous resin layer 3.SELECTED DRAWING: Figure 1

Description

The present invention relates to a low dielectric substrate material and a method for manufacturing the same.

In recent years, low dielectric polymer films are known to be useful as films for millimeter-wave antennas capable of long-distance wireless communication.

For example, a laminate including a copper foil and a polyimide porous film formed on the copper foil and having pores having a porosity of 60% or more and an average pore diameter of 50 μm or less has been proposed (for example, the following Patent Documents). See 1.). To manufacture this laminate, a copper foil is prepared, a polyimide precursor layer is formed on the copper foil, and then the polyimide precursor layer is foamed and cured to produce a polyimide porous film.

International publication 2018/186486 gazette

However, when the laminated body is pressed by a flat plate press in the circuit forming step of forming a circuit from the copper foil, the thickness of the polyimide porous film varies. Therefore, the dielectric constant varies depending on the location in the circuit, and as a result, the characteristic impedance becomes nonuniform in the circuit. Then, there is a problem that a part of the signal current flowing in the circuit is reflected and becomes noise, or the output is lowered.

In order to solve the above problems, the present invention provides a low dielectric substrate material that can make the thickness of the porous resin layer uniform, and a method for manufacturing the same.

The present invention (1) includes a metal layer, a porous resin layer disposed on one side in the thickness direction of the metal layer, and the one side surface of the metal layer disposed adjacent to the porous resin layer. A low dielectric substrate material having a spacer layer thinner than the porous resin layer.

This low dielectric substrate material comprises a spacer layer thinner than the porous resin layer. Therefore, if this low dielectric substrate material is pressed in the thickness direction, the porous resin layer can be pressed up to the thickness of the spacer layer, but the pressing beyond that can be suppressed. Therefore, it is possible to prevent the thickness of the porous resin layer from becoming uneven due to excessive pressing. That is, the spacer layer can control the pressing amount (compression amount) to make the thickness of the porous resin layer uniform.

In the present invention (2), the metal layer is a first margin area and a second margin area which are respectively arranged at one end and the other end in a first direction included in a plane direction orthogonal to the thickness direction. And including the first margin area and the second margin area that are included in the plane direction and extend in a second direction orthogonal to the first direction, the spacer layer, when projected in the thickness direction, The low dielectric substrate material according to (1), including a first spacer member included in a first margin area and a second spacer member included in the second margin area.

In this low dielectric substrate material, since the spacer includes the first spacer member and the second spacer member which are respectively arranged at one end and the other end in the first direction, the pressing amount in the first direction is made uniform. be able to. Therefore, the thickness of the porous resin layer in the first direction can be made uniform.

The present invention (3) includes the low dielectric substrate material according to (2), wherein the first spacer member and the second spacer member have a shape extending in the second direction.

In this low dielectric substrate material, the first spacer member and the second spacer member have a shape extending in the second direction. Therefore, the thickness of the porous resin layer in the second direction can be made uniform.

In the present invention (4), the first spacer member is arranged at each of the one end portion and the other end portion in the second direction of the first margin area, and they are separated from each other in the second direction. The second spacer member is arranged at each of the one end and the other end in the second direction of the second margin area, and they are separated from each other in the second direction. Including low dielectric substrate material.

In this low dielectric substrate material, the first spacer member is arranged at each of the one end portion and the other end portion of the first margin area in the second direction, and the second spacer member is arranged at the one end portion of the second margin area in the second direction. It is arranged at each of the other ends. Therefore, the pressing amount in the second direction can be made uniform. Therefore, the thickness of the porous resin layer in the second direction can be made uniform.

The present invention (5) includes the low dielectric substrate material according to any one of (1) to (4), wherein the spacer layer is a non-porous layer.

In this low dielectric substrate material, the spacer layer is a non-porous layer, and thus is harder than the porous resin layer. Therefore, the function of the spacer layer can be sufficiently exerted.

In the present invention (6), the porous resin layer has a first side surface facing the spacer layer, the spacer layer has a second side surface facing the porous resin layer, and The low dielectric substrate material according to any one of (1) to (5), wherein the side surface and the second side surface are in close contact with each other.

In this low dielectric substrate material, since the first side surface and the second side surface are in close contact with each other, it is possible to prevent the porous resin layer from shifting with respect to the spacer layer when the low dielectric substrate material is pressed. ..

The present invention (7) includes the low dielectric substrate material according to any one of (6), wherein the porous resin layer and the spacer layer are made of the same material.

In this low dielectric substrate material, since the porous resin layer and the spacer layer are made of the same material, the adhesion between the first side surface and the second side surface can be improved.

The present invention (8) is a method for producing the low dielectric substrate material according to any one of (1) to (7), wherein a spacer material is applied to the one surface of the metal layer to form a first dielectric material. A first step of forming a coating film; a second step of applying a resin material to the one surface of the metal layer so as to be adjacent to the spacer material to form a second coating film; A third step of foaming the coating film to form a porous coating film, a fourth step of curing the first coating film to form the spacer layer, and a curing of the porous coating film, And a fifth step of forming the porous resin layer, including a method for manufacturing a low dielectric substrate material.

In this method, the first step, the second step, and the third step can be sequentially performed, and the fourth step and the fifth step can be sequentially performed. Therefore, in this method, the first step and the fourth step are sequentially performed, and then the second step, the third step, and the fifth step are sequentially performed, and the second step, the third step, and the fifth step are performed. The fourth step and the fifth step can be performed with higher manufacturing efficiency than the method of sequentially performing the first step and the fourth step after sequentially performing the steps.

The present invention (9) includes the method for manufacturing a low dielectric substrate material according to (8), wherein the fourth step and the fifth step are simultaneously performed.

In this manufacturing method, since the fourth step and the fifth step are carried out simultaneously, the low dielectric substrate material can be manufactured in a short time.

According to the low dielectric substrate material of the present invention, the spacer layer can control the pressing amount (compression amount) to make the thickness of the porous resin layer uniform.

According to the method for manufacturing a low dielectric substrate material of the present invention, the fourth step and the fifth step can be efficiently performed.

1A to 1B show one embodiment of the low dielectric substrate material of the present invention, FIG. 1A is a plan view, and FIG. 1B is a sectional view taken along line XX of FIG. 1A. 2A to 2F are process diagrams for explaining the method of manufacturing and processing the low dielectric substrate material shown in FIG. 1. FIG. 2A is a process of preparing a metal layer, and FIG. 2B is a process of forming a first coating film. 2C is a second step of forming a second coating film, FIG. 2D is a third step of forming a porous coating film, a fourth step of forming a spacer layer, and a porous resin layer. 2E shows a step of pressing the low dielectric substrate material, and FIG. 2F shows a step of obtaining the pressed low dielectric substrate material. FIG. 3 is a modification example of the low dielectric substrate material shown in FIG. 1A (first spacer members are arranged at one end and the other end of the first margin area in the second direction, respectively, and second spacer members are arranged at the second margin). The top view of the modification which is arrange|positioned at each one end part and the other end part of the area in the second direction. FIG. 4 is a modification example of the low dielectric substrate material shown in FIG. 1A (the first spacer member is arranged at one end of the first margin area in the second direction, and the second spacer member is arranged in the second direction of the second margin area, etc.). The top view of the modification) arrange|positioned at an edge part is shown. FIG. 5 is a modification example of the low dielectric substrate material shown in FIG. 1A (the first spacer member is arranged in the middle portion in the second direction of the first margin area, and the second spacer member is arranged in the second direction of the second margin area). The top view of the modification arrange|positioned at the intermediate part) is shown. FIG. 6 is a plan view of a modified example of the low dielectric substrate material shown in FIG. 1A (a modified example in which the spacer layer is composed of the first spacer member that matches the first margin area). FIG. 7 is a plan view of a modified example of the low dielectric substrate material shown in FIG. 1A (a modified example in which the spacer layer is a first spacer member arranged at one end of the first margin area in the first direction). FIG. 8 shows the measurement points of the dimensions and thickness of the low dielectric substrate material of Example 1. FIG. 9 shows measurement points of dimensions and thickness of the low dielectric substrate material of Comparative Example 1.

<One Embodiment>
One embodiment of the low dielectric substrate material of the present invention will be described with reference to FIGS. 1A to 1B.

The low dielectric substrate material 1 has one surface and the other surface facing each other in the thickness direction, and has a sheet shape that spreads in a surface direction orthogonal to the thickness direction. The low dielectric substrate material 1 includes a metal layer 2, a porous resin layer 3, and a spacer layer 4. Preferably, the low dielectric substrate material 1 includes only the metal layer 2, the porous resin layer 3, and the spacer layer 4.

The metal layer 2 has the same outer shape as that of the low dielectric substrate material 1. Specifically, the metal layer 2 has one surface and the other surface facing each other in the thickness direction, and has a sheet shape spreading in the surface direction. Moreover, one surface in the thickness direction of the metal layer 2 is a flat surface. Further, the metal layer 2 forms the other surface in the thickness direction of the low dielectric substrate material 1.

More specifically, the metal layer 2 has a substantially rectangular sheet shape, and is arranged at each of one end and the other end in the first direction (the direction corresponding to the left-right direction in FIG. 1A) included in the plane direction. It has a first margin area 5 and a second margin area 6.

The first margin area 5 and the second margin area 6 are areas where the porous resin layer 3 described below is not arranged. The first margin area 5 and the second margin area 6 are spaced from each other in the first direction. Each of the first margin area 5 and the second margin area 6 is a substantially strip-shaped area in plan view extending in a second direction (corresponding to the vertical direction in FIG. 1A) orthogonal to the first direction.

The material of the metal layer 2 is not particularly limited, and examples thereof include metals such as copper, iron, silver, gold, aluminum, nickel, and alloys thereof (stainless steel, bronze). Preferably, copper is used.

The thickness of the metal layer 2 is, for example, 0.1 μm or more, preferably 1 μm or more, and for example, 100 μm or less, preferably 50 μm or less.

The porous resin layer 3 is arranged on one surface of the metal layer 2. Specifically, the porous resin layer 3 is arranged on the one surface of the metal layer 2 between the first margin area 5 and the second margin area 6. The porous resin layer 3 forms one surface of the low dielectric substrate material 1 together with the spacer layer 4 described below.

The porous resin layer 3 has one surface and the other surface facing each other in the thickness direction, and has a sheet shape that spreads between the first margin area 5 and the second margin area 6 on one surface of the metal layer 2. In addition, the porous resin layer 3 includes a first outer side surface 9 as an example of a first side surface that connects one edge in the first direction of one side and one edge in the first direction of the other side, and one side in the first direction and the like. The second outer side surface 10 as an example of the first side surface that connects the end edge and the other end edge of the other surface in the first direction. As a result, the one surface in the thickness direction, the other surface, the first outer surface 9 and the second outer surface 10 define a substantially rectangular shape. That is, the porous resin layer 3 has a substantially rectangular shape in the cross section along the first direction.

The porous resin layer 3 is not particularly limited, and examples thereof include a porous film (preferably a polyimide porous film) described in International Publication No. 2018/186486.

Moreover, the porous resin layer 3 has a large number of fine pores (pores). The porous resin layer 3 mainly has, for example, a closed cell structure.

The porosity in the porous resin layer 3 is, for example, 60% or more, preferably 70% or more, more preferably 80% or more, and for example, less than 100%.

The average diameter of the pores 10 in the porous resin layer 3 (that is, the average pore diameter) is, for example, 10 μm or less, and for example, 0.1 μm or more.

The material of the porous resin layer 3 (an example of a resin material) is not particularly limited, and examples thereof include resins such as thermosetting resins and thermoplastic resins. Preferably, a thermosetting resin is used.

Examples of the thermosetting resin include polycarbonate resin, thermosetting polyimide resin, thermosetting fluorinated polyimide resin, epoxy resin, phenol resin, urea resin, melamine resin, diallyl phthalate resin, silicone resin, thermosetting urethane resin. , Fluororesins (polymers of fluorinated olefins (specifically, polytetrafluoroethylene (PTFE), etc.)), liquid crystal polymers (LCP), and the like. These can be used alone or in combination of two or more. Preferably, a thermosetting polyimide resin is used.

The dielectric constant of the porous resin layer 3 at a frequency of 10 GHz is, for example, 3.0 or less, preferably 2.5 or less, more preferably 2.0 or less.

The thickness of the porous resin layer 3 is, for example, 2 μm or more, preferably 5 μm or more, more preferably 25 μm or more, further preferably 50 μm or more, particularly preferably 75 μm or more, and, for example, 1,000 μm. It is preferably 500 μm or less, and more preferably 250 μm or less. The thickness of the porous resin layer 3 is the distance between one surface in the thickness direction of the porous resin layer 3 and one surface in the thickness direction of the metal layer 2. The thickness of the porous resin layer 3 is an average thickness in the surface direction.

The ratio of the thickness of the porous resin layer 3 is, for example, 1 μm or more, preferably 5 μm or more, and, for example, 100 μm or less, more preferably 50 μm or less, more preferably 20 μm or less.

The ratio of the thickness of the porous resin layer 3 to the thickness of the metal layer 2 is, for example, 2 or more, preferably 5 or more, and for example, 100 or less, more preferably 50 or less.

The spacer layer 4 is a layer extending in the surface direction so that the pressing of the porous resin layer 3 can be controlled in the pressing (see FIG. 2E) described later.

The spacer layer 4 forms one surface in the thickness direction of the low dielectric substrate material 1 together with the porous resin layer 3 described above. The spacer layer 4 has a smooth one surface and a smooth other surface facing each other in the thickness direction. One surface of the spacer layer 4 is exposed on one side in the thickness direction. The other surface of the spacer layer 4 is in contact with the one surface of the metal layer 2.

The spacer layer 4 is arranged on one surface of the metal layer 2. Specifically, the spacer layer 4 is arranged adjacent to the porous resin layer 3 in the first direction on one surface of the metal layer 2. Specifically, the spacer layer 4 and the porous resin layer 3 are arranged without a gap in the first direction.

Specifically, the spacer layer 4 is arranged in the first margin area 5 and the second margin area 6 on one surface of the metal layer 2. The spacer layer 4 includes a first spacer member 7 included in the first margin area 5 and a second spacer member 8 included in the second margin area 6 when projected in the thickness direction.

The first spacer member 7 has a generally rectangular shape in plan view extending in the first direction. The first spacer member 7 overlaps with the first margin area 5 when projected in the thickness direction. That is, the entire other surface of the first spacer member 7 is in contact with the entire one surface of the first margin area 5. That is, the first spacer member 7 corresponds to the first margin area 5 in a plan view. Specifically, each of the first direction one end edge, the first direction other end edge, the second direction one end edge, and the second direction other end edge of the first spacer member 7 is a first direction one end edge of the first margin area 5, It corresponds to each of the other edge in the first direction, one edge in the second direction, and the other edge in the second direction. The first spacer member 7 has a substantially rectangular shape in a cross-sectional view along the first direction, and is one example of a second side surface that connects one surface, the other surface, and their other ends in the first direction. The inner surface 11 is integrally formed. The first inner side surface 11 faces the first outer side surface 9 of the porous resin layer 3. The first inner side surface 11 contacts the first outer side surface 9.

The second spacer member 8 has a substantially rectangular shape in plan view extending in the first direction. The second spacer member 8 overlaps the second margin area 6 when projected in the thickness direction. That is, the entire other surface of the second spacer member 8 is in contact with the entire one surface of the second margin area 6. That is, the second spacer member 8 coincides with the second margin area 6 in a plan view. Specifically, each of the first direction one edge, the first direction other edge, the second direction one edge, and the second direction other edge of the second spacer member 8 is a first direction one edge of the second margin area 6, It corresponds to each of the other edge in the first direction, one edge in the second direction, and the other edge in the second direction. The second spacer member 8 has a substantially rectangular shape in a cross-sectional view along the first direction, and has one surface, the other surface, and a second inner surface as an example of a second side surface that connects the one end edges in the first direction. It has the side surface 12 integrally. The second inner side surface 12 faces the second outer side surface 10 of the porous resin layer 3. The second inner side surface 12 contacts the second outer side surface 10.

The spacer layer 4 is not particularly limited as long as the pressing of the porous resin layer 3 can be controlled, and is preferably a non-porous layer. That is, unlike the porous resin layer 3, the spacer layer 4 preferably does not have fine pores (pores) and is formed as a solid dense layer.

Examples of the material of the spacer layer 4 (an example of the spacer material) include the above-mentioned resins such as thermosetting resin and thermoplastic resin. In addition, as the material of the spacer layer 4, the metal exemplified in the metal layer 2 can also be used. As a material of the spacer layer 4, a resin is preferable, a thermosetting resin is more preferable, and a thermosetting polyimide resin is more preferable.

The material of the spacer layer 4 is preferably the same resin as the resin exemplified in the porous resin layer 3, more preferably the same thermosetting resin as the thermosetting resin exemplified in the porous resin layer 3. More preferably, the same material as the material of the porous resin layer 3 is used.

The spacer layer 4 is thinner than the porous resin layer 3. That is, the thickness of the spacer layer 4 is less than the thickness of the porous resin layer 3.

The value obtained by subtracting the thickness of the spacer layer 4 from the thickness of the porous resin layer 3 is, for example, more than 0 μm, preferably 1 μm or more, more preferably 2 μm or more, further preferably 5 μm or more, and, for example, It is 50 μm or less, preferably 25 μm or less.

The thickness of the spacer layer 4 is the distance between the one surface in the thickness direction of the spacer layer 4 and the one surface in the thickness direction of the metal layer 2.

The ratio of the thickness of the spacer layer 4 to the thickness of the porous resin layer 3 is, for example, less than 1 or less, preferably 0.99 or less, more preferably 0.95 or less, and, for example, 0.5 or more. , Preferably 0.6 or more, more preferably 0.7 or more, and further preferably 0.8 or more.

The thickness of the spacer layer 4 is, for example, 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and for example, 100 μm or less, preferably 50 μm or less, more preferably 30 μm or less.

The thickness of the spacer layer 4 is substantially uniform in the plane direction, that is, the spacer layer 4 has the same thickness in the plane direction.

Further, since the first spacer member 7 is thinner than the porous resin layer 3, the first spacer member 7 exposes one side portion in the thickness direction of the first outer side surface 9 of the porous resin layer 3 to one side in the first direction. doing. Further, the first inner side surface 11 of the first spacer member 7 is in close contact with the other side portion of the first outer side surface 9 of the porous resin layer 3 in the thickness direction.

Since the second spacer member 8 is thinner than the porous resin layer 3, the second spacer member 8 exposes one portion in the thickness direction on the second outer side surface 10 side to the other side in the first direction. Further, the second inner side surface 12 of the second spacer member 8 is in close contact with the portion of the second outer side surface 10 of the porous resin layer 3 on the other side in the thickness direction.

The first direction length of each of the first spacer member 7 and the second spacer member 8 is, for example, 0.1 cm or more, preferably 0.5 cm or more, and for example, 5 cm or less, preferably 2 cm or less. Is.

The ratio of the first direction length of each of the first spacer member 7 and the second spacer member 8 to the first direction length of the metal layer 2 is, for example, 0.01 or more, preferably 0.02 or more, It is preferably 0.05 or more, and for example, 0.2 or less, preferably 0.1 or less.

The thickness of the low dielectric substrate material 1 is the total thickness of the metal layer 2 and the porous resin layer 3, and is, for example, 10 μm or more, preferably 15 μm or more, more preferably 30 μm or more. 2,000 μm or less, preferably 600 μm or less, preferably 300 μm.

The ratio of the thickness of the metal layer 2 to the thickness of the low dielectric substrate material 1 is, for example, 0.01 or more, preferably 0.05 or more, and for example, 0.75 or less, preferably 0.25 or less. Is.

The ratio of the thickness of the porous resin layer 3 to the thickness of the low dielectric substrate material 1 is, for example, 0.99 or less, preferably 0.95 or less, and, for example, 0.25 or more, preferably 0. It is 75 or more.

Next, a manufacturing method and a processing method of the low dielectric substrate material 1 will be described with reference to FIGS. 2A to 2F.

In the production of the low dielectric substrate material 1 in one embodiment (FIGS. 2A to 2D), each member is, for example, in the second direction (paper thickness direction in FIGS. 2A to 2D) by a roll-to-roll method. It is formed while being conveyed.

As shown in FIG. 2A, first, the metal layer 2 is prepared.

As shown in FIG. 2B, next, a spacer material (preferably a resin) is arranged in the first margin area 5 and the second margin area 6 on one surface of the metal layer 2 (implementation of the first step). Preferably, a first varnish containing a resin and a solvent is prepared, and the first varnish is applied (printed) to the first margin area 5 and the second margin area 6 of the metal layer 2 at the same time, and then dried simultaneously to remove the solvent. Are removed to form the first coating film 13.

When the resin is a thermosetting resin, a first varnish containing the precursor resin is prepared, the first varnish is applied to the first margin area 5 and the second margin area 6 of the metal layer 2, and then Then, the solvent is removed by drying to form the first coating film 13 made of the precursor resin. In this case, the first coating film 13 is still in an uncured state.

The solvent is not particularly limited, and examples thereof include organic solvents such as N-methyl-2-pyrrolidone (NMP). The solid content concentration in the first varnish is adjusted to, for example, 10% by mass or more and 50% by mass or less. The method for applying the first varnish is not particularly limited, and for example, an applicator or the like that can move (apply) in the second direction relative to the metal layer 2 is used.

The first coating film 13 is made of a spacer material and has substantially the same shape and size as the spacer layer 4.

As shown in FIG. 2C, next, the resin material is arranged between the first margin area 5 and the second margin area 6 on the one surface of the first metal layer 3 (implementation of the second step). The resin material contains the above-mentioned resin (preferably the same resin as the spacer layer 4), a porosifying agent, and a nucleating agent, and a second varnish containing this resin material and a solvent is prepared. Then, the second varnish is applied (printed) between the first margin area 5 and the second margin area 6 on the one surface of the first metal layer 3, and then dried to remove the solvent to remove the second coating film. 14 is formed.

The method for forming the second coating film 14 can be based on the description in International Publication No. 2018/186486.

The second coating film 14 is made of a resin material (a foamable composition containing a resin and a nucleating agent) and has the same planar view shape as the porous resin layer 3.

The second coating film 14 is, for example, thinner than the first coating film 13, and specifically, the other surface of the second coating film 14 is in contact with one surface of the metal layer 2 while the second coating film 14 is in contact with the first coating film 13. One surface of the film 14 is disposed on the other side in the thickness direction than one surface in the thickness direction of the first coating film 13 when projected in the first direction. Specifically, the entire surface of the first outer side surface 9 of the second coating film 14 is in contact with the portion on the other side in the thickness direction of the first inner side surface 11 of the first coating film 13 corresponding to the first spacer member 7. .. The entire second outer side surface 10 of the second coating film 14 is in contact with the portion of the second inner side surface 12 of the first coating film 13 corresponding to the second spacer member 8 on the other side in the thickness direction.

The second coating film 14 is adjacent to the first coating film 13 in a close contact in the first direction.

Thereafter, as shown in FIG. 2D, the second coating film 14 is foamed to form the porous coating film 19 (implementation of the third step).

The foaming method of the second coating film 14 is not particularly limited, and examples thereof include a physical foaming method and a chemical foaming method. Examples of the physical foaming method include a method in which a porosifying agent, a nucleating agent, etc. are dispersed in a resin, and a bubble is formed by extracting the pouring agent using a supercritical fluid (supercritical extraction method). Examples thereof include a method of dispersing a boiling point liquid (foaming agent) in a resin and then volatilizing the foaming agent to form bubbles (low boiling point liquid volatilization method). The supercritical extraction method is described in detail, for example, in International Publication No. 2018/186486.

Examples of the chemical foaming method include a method of forming bubbles by a gas generated by thermal decomposition of a compound added to a resin.

When the resin material contains a thermosetting resin, the porous coating film 19 is preferably in a state before complete curing.

After that, when the first coating film 13 and the porous coating film 19 contain a thermosetting resin, the first coating film 13 and the porous coating film 19 are cured respectively, and the spacer layer 4 and the porous resin layer. 3 are formed respectively (implementation of the fifth step).

Specifically, the first coating film 13 and the porous coating film 19 are heated at the same time.

As a result, the first coating film 13 containing the thermosetting resin is thermoset.

On the other hand, the porous coating film 19 containing the thermosetting resin is thermoset.

Thereby, the spacer layer 4 and the porous resin layer 3 are formed. The porous resin layer 3 is formed such that the first outer side surface 9 and the second outer side surface 10 thereof are in close contact with the first inner side surface 11 and the second inner side surface 11 of the spacer layer 4, respectively.

Thereby, the low dielectric substrate material 1 including the metal layer 2, the porous resin layer 3 and the spacer layer 4 is obtained.

After that, one side in the thickness direction of the porous resin layer 3 is pressed to make the thickness uniform. For this processing, for example, a batch method is adopted.

As shown in FIG. 2E, for pressing the porous resin layer 3, for example, a flat plate pressing machine 15 including an upper plate 16 and a lower plate 17 is used. The flat plate press 15 may be provided with a heat source (not shown). The other surface in the thickness direction of the upper plate 16 is a flat surface. One surface in the thickness direction of the lower plate 17 is a flat surface. The other surface of the upper plate 16 and the one surface of the lower plate 17 are substantially parallel to each other. Specifically, the upper plate 16 and the lower plate 17 are relatively movable in the thickness direction while the other surface of the upper plate 16 and one surface of the lower plate 17 are kept substantially parallel to each other.

First, the low dielectric substrate material 1 is placed in the flat plate press 15. Specifically, the other surface in the thickness direction of the metal layer 2 is brought into contact with one surface in the thickness direction of the lower plate 17.

As shown in FIG. 2E, the upper plate 16 is then pressed against the low dielectric substrate material 1 in the thickness direction. Specifically, the upper plate 16 is moved to the other side in the thickness direction while the other side in the thickness direction of the upper plate 16 is in contact with the one side in the thickness direction of the low dielectric substrate material 1.

Thereby, first, one surface in the thickness direction of the porous resin layer 3 moves toward the other side in the thickness direction. That is, the porous resin layer 3 is pressed in the thickness direction.

Subsequently, when the other surface in the thickness direction of the upper plate 16 contacts the one surface in the thickness direction of the spacer layer 4, the movement of the other surface in the thickness direction of the upper plate 16 to the other side in the thickness direction is restricted, and the porous resin layer 3 is formed. Press does not proceed any further.

That is, the pressing of the porous resin layer 3 in the thickness direction is performed so that the upper plate 16 of the flat plate press 15 contacts the spacer layer 4. Specifically, the porous resin layer 3 is pressed by a value obtained by subtracting the thickness of the spacer layer 4 from the thickness of the porous resin layer 3 before pressing.

Subsequently, the state where the upper plate 16 is in contact with the spacer layer 4 is maintained for, for example, 1 minute or more, preferably 5 minutes or more, more preferably 15 minutes or more, and for example, 60 minutes or less. That is, the pressing of the porous resin layer 3 is performed only for the time described above.

Further, the low dielectric substrate material 1 can be heated together with the pressing. The heating temperature is, for example, 100° C. or higher, preferably 150° C. or higher, and for example, 210° C. or lower, preferably 195° C. or lower.

After that, as shown in FIG. 2F, the press by the flat plate press 15 is released.

This allows the porous resin layer 3 to have its thickness restored. That is, it is allowed that one surface in the thickness direction of the porous resin layer 3 is arranged above the one surface in the thickness direction of the spacer layer 4.

Then, the thickness of the porous resin layer 3 after pressing becomes uniform in the surface direction.

The ratio of the thickness of the porous resin layer 3 after pressing to the thickness of the porous resin layer 3 before pressing is, for example, less than 1, further 0.99 or less, and, for example, 0.5 or more, Furthermore, it is 0.8 or more.

Then, if necessary, if the low dielectric substrate material 1 is manufactured by the roll-to-roll method, the low dielectric substrate material 1 is cut along the first direction.

The low dielectric substrate material 1 includes a spacer layer 4 thinner than the porous resin layer 3. Therefore, in order to make the thickness of the porous resin layer 3 uniform, as shown in FIG. 2E, if the low dielectric substrate material 1 is pressed in the thickness direction, the porous resin layer 3 will not reach the thickness of the spacer layer 4. While being pressed, it can suppress pressing more than that. Therefore, it is possible to prevent the thickness of the porous resin layer 3 from becoming uneven due to excessive pressing. That is, the spacer layer 4 can control the pressing amount (compression amount) to make the thickness of the porous resin layer 3 uniform.

Further, in the low dielectric substrate material 1, the spacer layer 4 opposes the first spacer member 7 and the second spacer member 8 arranged at each of the one end and the other end in the first direction in the first direction. As described above, the pressing amount in the first direction can be made uniform. Therefore, the thickness of the porous resin layer 3 in the first direction can be made uniform.

Further, in the low dielectric substrate material 1, the first spacer member 7 and the second spacer member 8 have a shape extending in the second direction. Therefore, the pressing amount in the second direction can be made uniform. Therefore, the thickness of the porous resin layer 3 in the second direction can be made uniform.

Further, in this low dielectric substrate material 1, if the spacer layer 4 is a non-porous layer, it is harder than the porous resin layer 3. Therefore, the function of the spacer layer 4 and the uniform pressing of the porous resin layer 3 can be sufficiently exhibited.

Further, in the low dielectric substrate material 1, the first outer side surface 9 and the first inner side surface 11 are in close contact with each other, and the second outer side surface 10 and the second inner side surface 12 are in close contact with each other. In doing so, it is possible to prevent the porous resin layer 3 from shifting with respect to the spacer layer 4.

Further, in the low dielectric substrate material 1, if the porous resin layer 3 and the spacer layer 4 are made of the same material, the adhesion between the first outer side surface 9 and the first inner side surface 11 and the second outer side surface 10 and The adhesion of the second inner side surface 12 can be improved.

Modifications In the following modifications, the same members and steps as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In addition, each modified example can achieve the same operational effect as that of the embodiment except for the special mention. Furthermore, one embodiment and its modifications can be combined as appropriate.

In a modification, although not shown, the first step and the fourth step can be sequentially performed, and then the second step, the third step, and the fifth step can be sequentially performed. That is, first, the spacer material is arranged on the metal layer 2 to form the first coating film 13, and subsequently, when the first coating film 13 contains a thermosetting resin, the first coating film 13 is formed. Is heated to form the spacer layer 4 (implementation of the first and fourth steps). After that, the resin material is placed on the metal layer 2 to form the second coating film 14, and then the second coating film 14 is foamed to form the porous coating film 19. Next, when the porous coating film 19 contains a thermosetting resin, the porous coating film 19 is heated to form the porous resin layer 3 (implementation of the second, third and fifth steps). ). Conversely, the second step, the third step, and the fifth step can be sequentially performed, and then the first step and the fourth step can be sequentially performed.

Preferably, like 1 embodiment, a 1st process, a 2nd process, and a 3rd process are implemented in order, and a 4th process and a 5th process are then implemented in order. According to such an embodiment, the fourth step and the fifth step can be performed by heating with high manufacturing efficiency, and thus can be simultaneously performed, as compared with the method of the modification described above.

Furthermore, in one embodiment, since the fourth step and the fifth step are simultaneously performed, the low dielectric substrate material 1 can be manufactured in a short time.

Instead of the press shown in FIG. 2E, the flat plate press machine 15, for example, a roll press machine (not shown) can be used. With a roll pressing machine, the porous resin layer 3 can be pressed by the roll-to-roll method, so that the manufacturing efficiency is excellent.

The transport direction in the roll-to-roll method is not particularly limited, and the metal layer 2 can be transported along the first direction, for example.

Preferably, the metal layer 2 is conveyed along the second direction. When the metal layer 2 is conveyed in the second direction, each of the first coating film 13 and the second coating film 14 extending in the second direction can be easily applied by the applicator.

In the first step, the spacer material is applied (printed) in a pattern corresponding to the first margin area 5 and the second margin area 6 of the metal layer 2, and the first coating film 13 having the same pattern as that is formed. However, for example, by incorporating a photosensitive component in the spacer material, the photosensitive spacer material is first applied to the entire one surface in the thickness direction of the metal layer 2, and then exposed and developed to form the first margin area. It is also possible to pattern the first coating film 13 having a pattern corresponding to 5 and the second margin area 6.

In one embodiment, the first inner side surface 11 is in close contact with the first outer side surface 9 of the porous resin layer 3, but, for example, a gap may be provided between them. The second inner side surface 12 is in close contact with the second outer side surface 10 of the porous resin layer 3, but a gap may be provided between them, for example.

In one embodiment, the fourth step and the fifth step are carried out simultaneously, but they can also be carried out separately.

Each of the first spacer member 7 and the second spacer member 8 has a substantially rectangular shape in plan view, but the shape thereof is not particularly limited, and may be, for example, a circular shape in plan view or an elliptical shape in plan view.

In another modification, as shown in FIG. 3, the first spacer member 7 is arranged at each of the one end portion and the other end portion of the first margin area 5 in the second direction, and the first spacer member 7 is arranged at the second end. Spaced in the direction. The second direction intermediate portion of the first margin area 5 is exposed from between the two first spacer members 7.

The second spacer member 8 is arranged at each of the one end and the other end of the second margin area 6 in the second direction, and they are separated from each other in the second direction. A second direction intermediate portion of the second margin area 6 is exposed from between the two second spacer members 8.

The second spacer member 8 arranged at one end in the second direction of the second margin area 6 and the first spacer member 7 arranged at one end in the second direction of the first margin area 5 have the first The porous resin layer 3 is sandwiched in one direction. The second spacer member 8 arranged at the other end of the second margin area 6 in the second direction and the first spacer member 7 arranged at the other end of the first margin area 5 in the second direction in plan view. , The porous resin layer 3 is sandwiched in the first direction.

In this low dielectric substrate material 1, the first spacer member 5 is arranged at each of one end and the other end of the first margin area 7 in the second direction, and the second spacer member 6 is arranged at the second margin area 8. It is arranged at each of one end and the other end in two directions. Therefore, when pressing the porous resin layer 3, the pressing amount in the second direction can be made uniform. Therefore, the thickness of the porous resin layer 3 in the second direction can be made uniform.

Further, as shown in FIG. 4, the first spacer member 7 is arranged at one end of the first margin area 5 in the second direction, while the second spacer member 8 is arranged in the second margin area 6 in the second direction. It may be arranged at the end. The first spacer member 7 and the second spacer member 8 sandwich the porous resin layer 3 in a direction inclined in the first direction in a plan view.

In FIG. 5, the first spacer member 7 is arranged in the second direction intermediate portion (preferably the central portion) of the first margin area 5, while the second spacer member 8 is the second margin area 6 of the second margin area 6. It is arranged in the middle part (preferably the center part) in the direction. The first spacer member 7 and the second spacer member 8 sandwich the porous resin layer 3 in the first direction in a plan view.

Further, as shown in FIGS. 6 and 7, the spacer layer 4 may be arranged only in the first margin area 5. Specifically, the spacer layer 4 is composed of only the first spacer member 7.

In the modification of FIG. 6, the first spacer member 7 overlaps the first margin area 5 when projected in the thickness direction.

In the modification of FIG. 7, the first spacer member 7 is arranged at one end of the first margin area 5 in the second direction.

Preferably, as shown in FIGS. 1 and 3 to 5, the spacer layer 4 is arranged in both the first margin area 5 and the second margin area 6. According to the embodiment shown in FIG. 1 and the modified examples shown in FIGS. 3 to 5, the thickness of the pressed porous resin layer 3 in the first direction can be made uniform.

Further, although not shown, the spacer layer 4 may be arranged in a substantially L shape in plan view on one surface in the thickness direction of the metal layer 2.

Further, although not shown, the spacer layer 4 may be arranged in the middle portion of the metal layer 2 in the first direction, and the porous resin layers 3 may be arranged on both outer sides in the first direction.

In one embodiment, the low dielectric substrate material 1 after pressing is cut along the first direction. However, for example, the low dielectric substrate material 1 before pressing can also be cut along the first direction. ..

In the second step, as shown in FIG. 2C, the second coating film 14 is formed thinner than the first coating film 13, but the second coating film 14 may be formed to have the same thickness as the first coating film 13, for example. ..

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited to the examples and comparative examples. In addition, specific numerical values such as a blending ratio (content ratio), physical property values, and parameters used in the following description are described in the above-mentioned "Description of Embodiments", and a corresponding blending ratio ( Content ratio), physical property values, parameters, etc. may be replaced with the upper limit (values defined as “below” or “less than”) or the lower limit (value defined as “greater than or equal to” or “exceeded”). it can.

Example 1
A low dielectric substrate material 1 having the dimensions shown in FIG. 1 and shown in FIG. 8 was manufactured.

Specifically, as shown in FIG. 2A, first, a metal layer 2 made of copper having a length in the first direction of 14 cm, a length in the second direction of 12 cm, and a thickness of 12 μm was prepared.

Subsequently, the polyimide precursor ([BPDA/PDA, DPE]) (P-phenylenediamine/diaminodiphenyl ether, biphenyltetracarboxylic acid dihydrate) described in Reference Example of International Publication No. 2018/186486 and NMP are contained. A first varnish (solid concentration 20% by mass) is prepared, and then, as shown in FIG. 2B, this is applied to the first margin area 5 and the second margin area 6 by the width ( A first direction length of 1 cm) was applied at the same time, and then simultaneously dried to form a 125 μm-thick first coating film 13 made of a thermosetting polyimide precursor (implementation of the first step).

Then, a second varnish described in Example 1 of WO2018/186486 (20% by mass of solid content) was prepared, and as shown in FIG. 2C, the second varnish was applied to the first coating film 13 by an applicator. The second coating film 14 made of a thermosetting polyimide precursor having a thickness of 10 μm was formed by applying on one surface of the metal layer 2 in between and then drying (implementation of second step).

Subsequently, the porosifying agent was extracted from the second coating film 14 using supercritical carbon dioxide, and the second coating film 14 was foamed to form the porous coating film 19 (supercritical extraction method) (third method). Implementation of the process).

Then, the first coating film 13 and the porous coating film 19 were simultaneously heated under vacuum at 380° C. for 2 hours. Thereby, as shown in FIG. 2D, each of the first coating film 13 and the porous coating film 19 was cured to form the spacer layer 4 and the porous resin layer 3 (implementation of the fourth step and the fifth step). ).

The porous resin layer 3 was thicker than the spacer layer 4 and had an average thickness of 140 μm.

Thus, the low dielectric substrate material 1 including the metal layer 2, the porous resin layer 3 and the spacer layer 4 was manufactured.

Thereafter, as shown in FIG. 2E, the low dielectric substrate material 1 was pressed in the thickness direction with a flat plate press 15. The pressing pressure was 5 MPa, the pressing temperature was 180° C., and the pressing time was 30 minutes.

Then, as shown in FIG. 2F, the low dielectric substrate material 1 was taken out from the flat plate press 15.

Then, the thickness of the porous resin layer 3 at the measurement points A to R shown in FIG. 8 was determined using a thickness meter. Then, their standard deviations were calculated. The standard deviation indicates the degree of variation in the surface direction of the porous resin layer 3, and the low value of the standard deviation indicates that the thickness is uniform. The results are shown in Table 1.

Comparative Example 1
Except that the first coating film 13 and the spacer layer 4 were not formed, the same treatment as in Example 1 was carried out to manufacture the low dielectric substrate material 1 shown in FIG.

After pressing, the thickness of the porous resin layer 3 at points A to R shown in FIG. 9 was obtained using a thickness meter. Subsequently, their standard deviation was calculated. The results are shown in Table 2.

1 Low Dielectric Substrate Material 2 Metal Layer 3 Porous Resin Layer 4 Spacer Layer 5 First Margin Area 6 Second Margin Area 7 First Spacer Member 8 Second Spacer Member 9 First Outer Surface (One Example of First Side Surface)
10 2nd outer side surface (an example of 1st side surface)
11 1st inner side surface (an example of 2nd side surface)
12 Second inner side surface (an example of the second side surface)
13 First coating film 14 Second coating film 19 Porous coating film

Claims (9)

A metal layer,
A porous resin layer arranged on one surface in the thickness direction of the metal layer,
A low dielectric substrate material, comprising a spacer layer disposed on the one surface of the metal layer so as to be adjacent to the porous resin layer and thinner than the porous resin layer. The metal layer is a first margin area and a second margin area respectively arranged at one end portion and the other end portion in the first direction included in a surface direction orthogonal to the thickness direction and included in the surface direction. And having the first margin area and the second margin area extending in a second direction orthogonal to the first direction,
The spacer layer, when projected in the thickness direction,
A first spacer member included in the first margin area;
The low dielectric substrate material according to claim 1, further comprising a second spacer member included in the second margin area. The low dielectric substrate material according to claim 2, wherein the first spacer member and the second spacer member have a shape extending in the second direction. The first spacer member is arranged at each of the one end portion and the other end portion in the second direction of the first margin area, and they are spaced from each other in the second direction.
The second spacer member is arranged at each of the one end and the other end of the second margin area in the second direction, and they are spaced from each other in the second direction. Item 3. A low dielectric substrate material according to item 2. The low-dielectric substrate material according to claim 1, wherein the spacer layer is a non-porous layer. The porous resin layer has a first side surface facing the spacer layer,
The spacer layer has a second side surface facing the porous resin layer,
The low dielectric substrate material according to any one of claims 1 to 5, wherein the first side surface and the second side surface are in close contact with each other. The low dielectric substrate material according to claim 6, wherein the porous resin layer and the spacer layer are made of the same material. A method for manufacturing the low dielectric substrate material according to claim 1.
A first step of applying a spacer material to the one surface of the metal layer to form a first coating film;
A second step of applying a resin material to the one surface of the metal layer so as to be adjacent to the spacer material to form a second coating film;
A third step of foaming the second coating film to form a porous coating film;
A fourth step of curing the first coating film to form the spacer layer;

A fifth step of curing the porous coating film to form the porous resin layer, the method for producing a low dielectric substrate material. The method for manufacturing a low dielectric substrate material according to claim 8, wherein the fourth step and the fifth step are performed simultaneously.

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