JP2006192903A - Manufacturing method of metal foil laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means which does not need a mold releasing film, and manufactures a one-sided metal foil laminate of polymer capable of forming an optically anisotropic melt phase, especially, to provide a means to manufacture a one-sided metal foil laminate having a thin layer of the above polymer having improved isotropy. <P>SOLUTION: A double-sided metal foil laminate 11 comprising: a polymer layer 2 capable of forming an optically anisotropic melt phase; a metal foil layer 3 joined to the top surface thereof; and a metal foil layer 3 joined to the under surface thereof is torn to the thickness direction of the polymer layer 2 into the top surface and the under surface to manufacture a one-sided metal foil laminates (11a) and (11b). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a film (hereinafter referred to as “liquid crystal polymer”) formed from a polymer (hereinafter sometimes referred to as “liquid crystal polymer” ) that is pressure-bonded to a substrate (metal foil) and can form an optically anisotropic molten phase. The present invention relates to a coated body having an isotropic coating layer, which is obtained by peeling off a part of a film (sometimes referred to as a “film”), and a method for producing the same.
The present invention further relates to a metal foil laminate of a liquid crystal polymer obtained by tearing a part of a liquid crystal polymer film pressure-bonded to a metal foil in the layer thickness direction, and a method for producing the same. Here, the coated body refers to an object obtained by coating a coated body (metal foil) with a liquid crystal polymer to form a liquid crystal polymer coating layer.

  The liquid crystal polymer has (1) ability to be thermocompression bonded directly to the metal foil, (2) high heat resistance, (3) low hygroscopicity, (4) excellent thermal dimensional stability, (5) Excellent humidity dimensional stability, (6) Excellent high frequency characteristics, (7) Flame retardant without adding toxic halogen, phosphorus, antimony, etc. Excellent chemical properties, (9) Excellent radiation resistance, (10) Controllable thermal expansion coefficient, (11) Flexible at low temperatures, (12) High gas barrier properties (permeability of gases such as oxygen) Is very low).

This excellent liquid crystal polymer by thin coatings to be coated member such as a metal foil or a silicon flat plate or a ceramic flat Recently, precision circuit board, a multilayer circuit board, sealing material, and want to configure the material used, such as the package The demand is particularly high. In addition, coating as a protective layer for metals and the like that are easily corroded is required by utilizing heat resistance, chemical resistance, low water absorption, and gas barrier properties.

First, the first problem will be described.
Forming a thin film such as a resin on the surface of an object is well known as a lining process or a coating process, and the two are generally distinguished as follows. The main purpose of the coating is to form a continuous film on the substrate, and to protect it from contamination and corrosion, and to give it a decorative appearance, but it is also used for the purpose of imparting non-stickiness and low friction, and the lining is corrosion and erosion. This is a method for forming an internal thick film for protecting containers (tanks) and pipes used in a chemically and physically severe environment such as these, and they are similar in various respects and are difficult to distinguish. In general, it is common to call one with a coating thickness of 0.5 mm or more as a lining and a coating with a thickness less than 0.5 mm as a coating. On the other hand, the coating is mainly on the surface of a structure of several tens of microns. It is to form a film, and the lining is said to be a case of several hundred microns or more.
In any case, the present invention relates to a technique for forming a very thin film (thickness of 25 μm or less, mainly 15 μm or less) of a liquid crystal polymer on a substrate, and thus can be said to relate to coating.

  Durability against temperature changes is first noticed as an important item of coating performance, but this is a problem of how to cope with the difference in thermal expansion coefficient between the coated body and the coating layer. Typical coating methods are: • Dipping method (dipping method) • Flow coater method • Curtain coater method • Roll coater method • Electrodeposition method • Brush coating method • Spray method • Gas phase coating However, in the case of a liquid crystal polymer coating, these conventional coating methods cannot be applied. The reason is that the liquid crystal polymer molecules are aligned by the force applied in the process of making the molten liquid crystal polymer into a thin film due to the unique property of the liquid crystal polymer that the molecules are easy to align in the same direction, that is, easy to align. Therefore, since the physical properties such as the thermal expansion coefficient are significantly different (that is, anisotropic) in the direction of orientation and the direction perpendicular thereto, for example, the thermal expansion coefficients of the coated body and the liquid crystal polymer coating layer are all in the plane. This is because they cannot be matched in the direction of. Although it is possible to form a liquid crystal polymer film relatively thick on the surface of the body to be coated by conventional techniques, for example, with a thickness of 50 μm or more, the formed liquid crystal polymer film is anisotropic, and is practical as a coating layer. Could not be used. Furthermore, there has been no technique for thinning the liquid crystal polymer coat layer with improved isotropic properties, for example, to a thickness of 15 μm or less.

Next, the second problem will be described.
On circuit boards in the electronics field, a conductive metal foil and an electrically insulating film-like insulating material (film or sheet or film or sheet coated on the metal foil) are overlaid and pressure bonded. A metal foil laminate is used. Such a metal foil laminate includes a double-sided metal foil laminate in which an electrical insulating layer is sandwiched between two metal foil layers, and a single-sided metal foil laminate in which one metal foil layer and an electrical insulating layer are combined. There are two forms of the body, and it is said that the liquid crystal polymer having the above features is one of the ideal materials for the electrical insulating layer.

  As a method for producing a liquid crystal polymer metal foil laminate that does not lose the characteristics of the liquid crystal polymer, the following methods are conventionally known.・ In the case of a double-sided laminate, a liquid crystal polymer film is sandwiched between two metal foils and hot pressed with a hot plate or a hot roll to melt the liquid crystal polymer film and thermocompression bond the metal foil and the liquid crystal polymer. By manufacturing. On the other hand, in the case of a single-area layered body, a liquid crystal polymer film is sandwiched between one metal foil and one release film, and hot-pressed with a hot plate or a hot roll to melt the liquid crystal polymer film, After the metal foil and the liquid crystal polymer are thermocompression bonded, the release film is peeled off and removed.

  In such a conventional manufacturing method, there is no particular problem in the case of a double-sided metal laminate, but in the case of a single-sided metal laminate, the release film must be peeled off and removed, so that the release film is wasted, The high production cost was a serious problem. Moreover, in order to melt the liquid crystal polymer film, it is necessary to have a high temperature around 300 ° C., so the release film must be an excellent heat-resistant film, so that Teflon (registered trademark), polyimide, etc. Expensive ones were required and the high cost for the release film actually made it very difficult to produce a commercial base of a single-sided metal foil laminate of a liquid crystal polymer.

  In recent years, there has been an increasing demand for reducing the thickness of circuit boards, particularly in the electronics field. As described above, since the liquid crystal polymer is suitable for the electrical insulating layer of the circuit board, there is a strong demand for a circuit board composed of a thin liquid crystal polymer layer and a metal foil layer.

  Therefore, a liquid crystal polymer film is necessary as a thin liquid crystal polymer layer, but if it is formed normally, it becomes a film having strong molecular orientation in one direction. A film having a strong molecular orientation in one direction is a film that is easily torn in the direction of molecular orientation and has a thermal dimensional change rate that is significantly different between the direction of molecular orientation and its perpendicular direction, that is, an anisotropic film. It is difficult to use as an electrical insulating layer material. However, as indicated by the first problem, it is difficult to make an isotropic liquid crystal polymer as an electrically insulating material into a thin film of 15 μm or less, and in particular, a film with a film thickness of 10 μm or less is very difficult to manufacture. And no examples have been reported so far.

  In order to solve the first problem, the present invention provides a means for forming a liquid crystal polymer coat layer having anisotropy eliminated, that is, improved isotropic property, and particularly a thin liquid crystal. A means for forming a polymer coat layer is provided.

  Moreover, in order to eliminate the 2nd problem, this invention provides the manufacturing method of the single-sided metal foil laminated body which does not require a release film in manufacture of the single-sided metal foil laminated body of a liquid crystal polymer. Furthermore, this invention also provides the laminated body comprised by the liquid crystal polymer electric insulation layer and metal foil layer which eliminated the anisotropy.

In the coating method according to the present invention, a film formed from a liquid crystal polymer and having a molecular orientation SOR of 1.3 or less is bonded to a coated body (metal foil) by thermocompression bonding, and then a thin layer of the film is coated. Peel off the film to leave it on top. Thereby, a thin liquid crystal polymer coat layer can be easily formed.
The coated body having the coating layer left on the coated body according to the present invention has a polymer coating layer capable of forming an optically anisotropic molten layer, and the molecular orientation of the polymer layer is 1. .3 or less. Moreover, as for the preferable embodiment of the to-be-coated body which concerns on this invention, the thickness of the said coating layer is 15 micrometers or less. Therefore, since the coating layer of the coated body according to the present invention is isotropic while ensuring thinness, the above-mentioned excellent features of the liquid crystal polymer are utilized to obtain a precision circuit board, a multilayer circuit board, a sealing circuit. sealing material can be a material, such as packages.

Here, the molecular orientation degree SOR (Segment Orientation Ratio) is an index that gives the degree of molecular orientation of the segments constituting the molecule.
Unlike (Molecular Orientation Ratio), this is a value considering the thickness of the object. This molecular orientation degree SOR is calculated as follows.

  First, using a known microwave molecular orientation measuring instrument, for example, a microwave molecular orientation measuring instrument 61 manufactured by KS Systems, shown in FIG. Transmission intensity) is measured. The measuring device 61 includes a microwave generator 63 that generates a microwave MW having a predetermined wavelength to be irradiated onto the liquid crystal polymer film 65, a microwave resonant waveguide 64, and transmission intensity detection means 68. The microwave resonant waveguide 64 has a film 65 disposed at the center thereof so that the film surface is perpendicular to the traveling direction of the microwave MW, and the film 65 is placed on the microwave MW by a rotation mechanism (not shown). The microwave MW that passes through the film 65 is reflected by a pair of reflecting mirrors 67 and 67 provided at both ends, while being held in a rotatable state in the R direction within a plane perpendicular to the traveling direction of It resonates. The microwave transmission intensity after passing through the film 65 is detected by transmission intensity detection means 68. The transmission intensity detecting means 68 measures the transmission intensity of the microwave by a detection element 68a inserted at a predetermined position behind the microwave resonant waveguide 64.

Then, based on the measured value of the microwave transmission intensity, an m value (referred to as a refractive index) is calculated by the following equation.
m = (Z0 / Δz) × (1-νmax / ν0)
Where Z0 is a device constant, Δz is the average thickness of the object to be measured, νmax is the frequency that gives the maximum microwave transmission intensity when the microwave frequency is changed, and ν0 is zero when the average thickness is zero (ie, the object Is the frequency that gives the maximum microwave transmission intensity.

  Next, when the rotation angle in the R direction of the object with respect to the vibration direction of the microwave is 0 °, that is, the vibration direction of the microwave and the direction in which the molecules of the object are best oriented, the minimum microwave The degree of molecular orientation SOR is calculated by m0 / m90, where m is the m value when the transmission intensity is given and the m value is m90 when the rotation angle is 90 °.

In an ideal isotropic film, this index SOR is 1, and the SOR of a liquid crystal polymer film that is strongly molecularly oriented in one direction usually obtained by a T-die film forming method is about 1.5. Moreover, the SOR of the isotropic film usually obtained by the isotropic inflation film-forming method is 1.3 or less.
In addition, liquid crystal polymers include all types of liquid crystal polymers such as half type 1 liquid crystal polymers, full type 1 liquid crystal polymers, half type 2 liquid crystal polymers, full type 2 liquid crystal polymers [Liquid Crystal Polymers for Molding and Design, Sigma Publishing]. Includes liquid crystal polymer.

  As typical examples of the liquid crystal polymer, there can be mentioned known thermotropic liquid crystal polyesters and thermotropic liquid crystal polyester amides derived from the compounds classified as (1) to (4) and their derivatives. However, it goes without saying that there is an appropriate range of combinations of various raw material compounds in order to form a polymer liquid crystal.

  (1) Aromatic or aliphatic dihydroxy compounds (see Table 1 for typical examples)

  (2) Aromatic or aliphatic dicarboxylic acids (see Table 2 for typical examples)

  (3) Aromatic hydroxycarboxylic acids (see Table 3 for typical examples)

  (4) Aromatic diamine, aromatic hydroxyamine or aromatic aminocarboxylic acid (see Table 4 for typical examples)

  (5) As typical examples of the liquid crystal polymer obtained from these raw material compounds, copolymers (a) to (e) having the structural units shown in Table 5 can be mentioned.

  These liquid crystal polymers are preferably those having a transition temperature to an optically anisotropic melt phase in the range of 200 to 400 ° C., particularly 250 to 350 ° C., from the viewpoint of heat resistance and workability of the film. Moreover, you may mix | blend a lubricant, antioxidant, a filler, etc. within the range which does not impair the physical property as a film.

  The film made of the liquid crystal polymer is formed by a known production method such as a T-die method, an inflation method, or a method combining these methods. In particular, in the inflation method, stress is applied not only in the machine axis direction of the film (hereinafter abbreviated as MD direction) but also in the direction orthogonal to the direction (hereinafter abbreviated as TD direction). Since a film having a good balance between mechanical properties and thermal properties can be obtained, it can be used more suitably.

An important point of the present invention is that an isotropic liquid crystal polymer film is used as a coating material, and an anisotropic liquid crystal polymer film having a molecular orientation degree SOR exceeding 1.3 is used as a coating material and coated. Even if the anisotropic liquid crystal polymer coat layer is melted by heating later, this does not turn into an isotropic liquid crystal polymer coat layer. This is a basic behavior related to the molecular properties of the liquid crystal polymer, and it is the inventor that the anisotropic liquid crystal polymer coat layer does not become isotropic even when heated to a temperature 35 ° C. higher than the melting point of the liquid crystal polymer. Have been confirmed .

The liquid crystal polymer coat layer of the present invention is suitable for holding parts constituting an electronic circuit board or an electronic circuit, and a metal foil is a coated body. The material of the metal foil is selected from metals used for electrical connection, preferably gold, silver, copper, nickel, aluminum, iron, steel, tin, brass, magnesium, molybdenum, copper / nickel alloy , Copper / beryllium alloy, nickel / chromium alloy, silicon carbide alloy, graphite, and mixtures thereof.

  The second feature of the present invention is that a thick isotropic liquid crystal polymer film is first thermocompression bonded to a coated body, and then the film is peeled off from the coated body, and a thin liquid crystal polymer coating is formed on the coated body. There is to leave a layer. This is difficult with ordinary polymers, but it is only possible to use the coating method that makes it possible to take advantage of the excellent delaminating properties inherent in liquid crystal polymer films (the property of being peeled into a thin layer like mica inside the film). It is. In order to thermocompression bond the isotropic liquid crystal polymer film to the coated body while maintaining this excellent in-layer peelability, it is important not to raise the heating temperature above the melting point of the liquid crystal polymer.

  The liquid crystal polymer coat layer formed on the surface of the body to be coated by such a method can lose in-layer peelability by further heating to the melting point or higher. When the surface of the liquid crystal polymer coat layer is aligned with the surface of another object and the object to be coated and the other object are subjected to thermocompression bonding at a temperature equal to or higher than the melting point of the liquid crystal polymer, In-layer peeling does not occur in the liquid crystal polymer coat layer because it is heated above the melting point.

In the coated body having an isotropic liquid crystal polymer according to the present invention, the liquid crystal polymer coat layer preferably has a thickness of 15 μm or less.
The liquid crystal polymer film forming technique is a very advanced technique, and it is difficult to manufacture a thin film, which increases the manufacturing cost. Usually, since a liquid crystal polymer film having a thickness of 20 μm or more can be stably produced, it is relatively easy to form a liquid crystal polymer coat layer with a thickness of 20 μm or more, and in some cases, the above-described peeling process is required. It is also possible to form a liquid crystal polymer coat layer. Of course, by peeling off, the peeled surface has a fine roughness and is preferable as a surface to be bonded with an adhesive, so that a liquid crystal polymer coat layer having a thickness of 20 μm or more is formed through a peeling process. Is often important. The coated body according to the present invention is effective when a thin liquid crystal polymer coating layer is required particularly in an electronic circuit board and its components, and is isotropic with a thickness of 20 μm or less, particularly a thickness of 15 μm or less. In order to provide the liquid crystal polymer coat layer, the method described in claim 1 is the only practical one. The lower limit of the average thickness of the liquid crystal polymer coat layer that can be realized is as close to 0 as possible, and for example, a liquid crystal polymer coat layer having an average thickness of 1 μm or less can be easily realized, and the average is reduced under precisely controlled conditions. An isotropic liquid crystal polymer coat layer having a thickness of 0.1 μm or less can also be realized.

In the coated body having an isotropic liquid crystal polymer coat layer according to the present invention, the thermal expansion coefficient of the isotropic liquid crystal polymer coat layer is preferably equal to the thermal expansion coefficient of the coated body.
As described above in the “Background Art” section, it is desirable that the thermal expansion coefficient of the liquid crystal polymer coat layer is as close as possible to the thermal expansion coefficient of the coated body. In particular, if the deviation in dimensional change between the coated body and the coating layer with respect to a temperature change of 100 ° C. is 0.2% or less, it can be used as a precise coating layer for electronic parts and the like. Accordingly, the fact that the thermal expansion coefficient of the isotropic liquid crystal polymer coating layer and the thermal expansion coefficient of the coated body are equivalent here is plus or minus 20 ppm / ° C. (that is, plus) with respect to the thermal expansion coefficient of the coated body surface. Minus 2/1000 / ° C). In this way, to make the thermal expansion coefficient of the coated body and the coating layer close to each other, the simplest thing is to make the thermal expansion coefficient of the liquid crystal polymer film that is the raw material of the coating layer equal to the thermal expansion coefficient of the coated body. However, even if the thermal expansion coefficient of the liquid crystal polymer film as a raw material is different from the thermal expansion coefficient of the object to be coated, both the liquid crystal polymer coat layer formed using the liquid crystal polymer film can be heated. It is possible to make the thermal expansion coefficients of the same. If the heating temperature is controlled very precisely in the heat treatment, the thermal expansion coefficients of the coated body and the coating layer can be matched within the measurement error range. In order to control the thermal expansion coefficient when using a thermosetting resin such as an ordinary thermoplastic polymer or epoxy resin that does not exhibit liquid crystallinity for the coating layer, an inorganic powder or inorganic cloth is incorporated into the coating layer. Special operations such as controlling the fraction and controlling the crosslink density of the polymer molecules that make up the coat layer must be carried out. In the case of the liquid crystal polymer coat layer, the unique properties of the liquid crystal polymer molecules are used. By doing so, it can be realized by a simple operation of heat treatment.

  As described above, the present invention utilizes the characteristics that liquid crystal polymer molecules are easily oriented and have excellent in-layer peelability when formed into a film shape. In the process of peeling off the polymer film, in-layer peeling occurs, and a thin liquid crystal polymer coat layer is easily formed by leaving a part of the raw material liquid crystal polymer film in the thickness direction on the coated body. is there.

The method for producing a metal foil laminate of the liquid crystal polymer of the present invention described below is related to the above-mentioned liquid crystal polymer coating in that it is produced by utilizing the feature of peelability of the liquid crystal polymer in the layer.

  The method for producing a single-sided metal foil laminate according to the present invention comprises: a double-sided metal foil laminate comprising a liquid crystal polymer layer, a metal foil layer bonded to the upper surface thereof, and a metal foil layer bonded to the lower surface; From the first single-sided metal foil laminate composed of the liquid crystal polymer layer and the upper metal foil layer, and the liquid crystal polymer layer and the lower metal foil layer It divides | segments into the 2nd single-sided metal foil laminated body which becomes. As a result, a single-sided metal foil laminate can be manufactured without using a release film, which was necessary in the conventional method, and since two single-sided metal foil laminates can be manufactured in a single process, the production speed is Almost doubled.

In the method for producing a single-sided metal foil laminate according to the present invention, the double-sided metal foil laminate may be produced by sandwiching a film formed from a liquid crystal polymer in a layer form with two metal foils and hot pressing the film. preferable.
The single-sided metal foil laminate of the present invention is obtained by the above production method.
In the single-sided metal foil laminate of the present invention, the liquid crystal polymer layer is preferably 15 μm or less.
In the single-sided metal foil laminate of the present invention, the liquid crystal polymer layer preferably has a molecular orientation of 1.3 or less.

The mounting circuit board of the present invention is formed by using the above-described single-sided metal foil laminate and mounting and connecting electronic components on the laminate.
The multilayer mounted circuit board of the present invention uses a multilayer laminate in which this laminate or another laminate is stacked on the single-sided metal foil laminate, and an electronic component is mounted on the multilayer laminate and connected. It becomes.

In the method for producing a double-sided metal foil laminate of the present invention, the double-sided metal foil laminate is produced by superposing and heating the metal foil on the polymer layer side of the single-sided metal foil laminate.
The double-sided metal foil laminate of the present invention is obtained by the above production method.

  An apparatus for producing a single-sided metal foil laminate of the present invention is formed by a hot press apparatus that heat-presses a film formed from a liquid crystal polymer sandwiched between two metal foils in a thickness direction, and a hot press. And a splitting device for tearing a double-sided metal foil laminate composed of a liquid crystal polymer layer, a metal foil layer on the top surface thereof, and a metal foil layer on the bottom surface in the thickness direction of the polymer layer.

  An important point in the present invention is to utilize the property that the liquid crystal polymer layer is bisected in the thickness direction by the above-described intra-layer peelability, and the desired single-sided metal foil lamination without losing this property. It is to make a body. For this purpose, it is essential that the liquid crystal polymer layer is not melted even if it is softened, and the temperature of the liquid crystal polymer layer should not be raised beyond the melting point. However, the liquid crystal polymer layer does not necessarily have a constant melting point, and the melting point depends on the thermal history applied to the liquid crystal polymer layer. For example, if a liquid crystal polymer film or layer is placed in an environment that is near the melting point but lower than the melting point (for example, continuously 15 ° C. lower), the melting point increases with time, and finally the melting point is the original. The temperature rises by about 120 ° C. from the starting melting point. Thus, when the melting point rises from the starting point, the property that the liquid crystal polymer layer is divided into two in the thickness direction is not impaired as long as the temperature does not exceed the melting point at that time.

  Moreover, as a method of hot pressing, a hot press machine, a vacuum hot press machine, a hot roll press machine, and a press machine, a vacuum press machine, a roll press machine, etc. in which heating means are installed substantially adjacent to each other are used. be able to.

  The single-sided metal foil laminate can be used not only for circuit board applications but also for general-purpose plastic and metal foil laminate applications. However, particularly in circuit board applications, it is desirable that the physical properties such as the thermal expansion coefficient be the same as much as possible in the direction in which the liquid crystal polymer film as a raw material is formed and in the direction perpendicular thereto. However, the liquid crystal polymer is very easy to align molecules. When a liquid crystal polymer film is formed by a normal film forming method, the liquid crystal polymer constituting the film is strongly aligned in the film forming direction (molecular orientation degree SOR is about 1.5). Or more). When the liquid crystal polymer film strongly molecularly oriented in such a film forming direction is used as the raw material of the single-sided metal foil laminate, the liquid crystal polymer layer of the single-sided metal foil laminate is strongly oriented in the film forming direction equivalent to the raw film. Therefore, the physical properties such as the coefficient of thermal expansion differ between the film forming direction and the direction perpendicular thereto.

  Therefore, especially for circuit board applications, the liquid crystal polymer film used for the production of a single-sided metal foil laminate is isotropic (molecular orientation degree SOR is 1.3 or less, ideally desirable SOR is 1). Is desirable.

  As described above, the present invention provides a laminate composed of a liquid crystal polymer electrical insulating layer and a metal foil layer, and the liquid crystal polymer layer can be made thin, particularly a circuit board. It is desirable to provide a laminate in which the molecular orientation of the liquid crystal polymer electrical insulating layer is isotropic. Therefore, since the liquid crystal polymer layer of the one-area layered body of the present invention is isotropic while ensuring thinness, a circuit composed of a thin liquid crystal polymer layer and a metal foil layer that are strongly required to be realized. Realization of a substrate is possible.

  As described above, according to the present invention, means for forming an isotropic liquid crystal polymer coat layer is provided, and in particular, an isotropic liquid crystal polymer coat layer having a thickness of 15 μm or less, and further heat of the isotropic liquid crystal polymer coat layer. Means are provided for forming an isotropic liquid crystal polymer coat layer having an expansion coefficient equivalent to the thermal expansion coefficient of the substrate.

  Further, as described above, according to the means of the present invention, a single-sided metal foil laminate of a liquid crystal polymer can be produced without requiring a release film. For this reason, the cost required for the release film is reduced. Furthermore, since two single-sided metal foil laminates are manufactured from one double-sided metal foil laminate in a single process, it can be produced at a rate almost twice as fast as the conventional method for producing single-sided metal foil laminates. Productivity can be improved.

  Furthermore, as described above, the present invention provides a laminate composed of an ultrathin liquid crystal polymer layer and a metal foil layer, and further a laminate in which the molecular orientation of the liquid crystal polymer layer is uniform in any direction in the plane. It is to provide.

FIGS. 1A to 1C show a coating method using an isotropic liquid crystal polymer film according to the first embodiment of the present invention. As shown in FIG. 1 (a), the coated body 1 is obtained by thermocompression bonding a liquid crystal polymer film 2 to a coated body 3. The liquid crystal polymer film 2 has a molecular orientation SOR of 1.3 or less and a thickness of 15 μm or more. As shown in FIG. 1B, the other liquid crystal polymer film 2b is peeled off while leaving the thin liquid crystal polymer coat layer 2a on the body 3 to be coated. The step of peeling off the liquid crystal polymer film 2b can be easily performed because it utilizes the in-layer peelability of the liquid crystal polymer film. After the liquid crystal polymer film 2b is peeled off, as shown in FIG. 1 (c), the coated body 1 is obtained by coating the coated body 3 with a thin liquid crystal polymer layer 2a.
By this coating method, a coated body having a molecular orientation degree SOR of 1.3 or less and a liquid crystal polymer coat layer thickness of 15 μm or less can be produced.

2 (a) to 2 (g) show a method for producing a single-sided metal foil laminate that is a second embodiment of the present invention. A double-sided metal foil laminate 11 comprising the liquid crystal polymer film 2, the upper metal foil layer 3 and the lower metal foil layer 3 shown in FIG. 2 (a) is formed as shown in FIG. 2 (b). In the thickness direction Z, the upper surface and the lower surface are torn, for example, at the center in the thickness direction. As a result, as shown in FIG. 2 (c), from the first single-sided metal foil laminate 11 a composed of the upper metal foil layer 3 and the liquid crystal polymer layer 2, the lower metal foil layer 3 and the liquid crystal polymer layer 2. The second single-sided metal foil laminate 11b is divided.
The step of tearing the liquid crystal polymer layer 2 shown in FIG. 2 (b) can be easily performed because it uses the in-layer peelability of the liquid crystal polymer film as in the first embodiment. 2A to 2C, two single-sided metal foil laminates of a liquid crystal polymer can be produced simultaneously without using a release film.

  Further, as shown in FIG. 2D, when the metal foil 3a is superposed on the liquid crystal polymer layer 2 side of the single-sided metal foil laminate 11b and hot-pressed, the double-sided metal foil laminate 11c shown in FIG. However, the thickness of the liquid crystal polymer layer 2 is about half that of the double-sided metal foil laminate 11 before division. Further, as shown in FIG. 2 (f), when the double-sided metal foil laminate 11c is torn into the upper surface and the lower surface in the thickness direction Z, as shown in FIG. 2 (g), the upper surface metal foil layer 3a A first single-sided metal foil laminate 11d composed of the liquid crystal polymer layer 2 is divided into a second single-sided metal foil laminate 11e composed of the lower-surface metal foil layer 3 and the liquid crystal polymer layer 2. By repeating the steps of FIGS. 2D to 2G, the thickness of the liquid crystal polymer layer 2 can be further reduced.

  The specific example of the manufacturing equipment of the single-sided metal foil laminated body of this invention is shown in FIG. The manufacturing method of a single-sided metal foil laminated body is as follows. The metal foil 3 on the upper surface, the liquid crystal polymer film 2, and the metal foil 3 on the lower surface, which should be called raw materials of the single-sided metal foil laminates 11a and 11b, are overlapped, and the metal foils 3, 3 and the liquid crystal polymer film 2 are laminated in the preheating chamber 20. A double-sided metal foil laminate 11 of a liquid crystal polymer is formed by passing through an atmosphere of the same temperature and immediately pressing it with hot press rollers 21 and 21 as hot press devices. Subsequently, after passing the temperature adjustment chamber 22 in order to adjust the double-sided metal foil laminate 11 to an appropriate temperature for dividing the double-sided metal foil laminate 11 into the upper and lower surfaces, the double-sided metal foil laminate 11 is placed on the upper surface side in the dividing device 23. The single-sided metal foil laminate 11a and the single-sided metal foil laminate 11b are wound up in two on the lower surface side in the thickness direction.

  FIG. 4 shows a conceptual diagram of a mounting circuit board according to the third embodiment of the present invention. In the mounted circuit board 12, the metal foil 3 in the single-sided metal foil laminate 11a (FIG. 2C) manufactured in the second embodiment is a copper foil, and the copper foil other than the printed pattern portion is removed by etching. Thus, a circuit pattern is formed. On this circuit pattern, electronic components 13 such as resistors, coils, capacitors, and ICs are mounted and connected to the circuit pattern. Since the single-sided metal foil laminate 11a of the present invention can make the liquid crystal polymer layer 2 that is an electrical insulating layer thin, a thin mounting circuit board 12 can be realized.

  FIG. 5 shows a schematic cross-sectional view of a multilayer circuit board 14 in which the double-sided metal foil laminates of the present invention are stacked with the liquid crystal polymer film 4 interposed therebetween. The metal foil 3 in the double-sided metal foil laminate 11c (FIG. 2E) is a copper foil, and the double-sided metal foil laminate 11c removes the copper foil other than the pattern portion printed by etching, so that the circuit pattern is Is formed. Between the two double-sided metal foil laminates 11c on which this circuit pattern is formed, the liquid crystal polymer film 4 is sandwiched and hot-pressed, and then component mounting holes are formed and plated 5 is applied to form through holes 6. Since the double-sided metal foil laminate 11c of the present invention can make the liquid crystal polymer layer 2 that is an electrical insulating layer thin, a multilayer circuit board 14 having a small thickness can be realized.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by these Examples.

[Example 1]
A thermotropic liquid crystal polyester composed of 27 mol% of 6-hydroxy-2-naphthoic acid units and 73 mol% of p-hydroxybenzoic acid units was heated and kneaded at 280-300 [deg.] C. using a single screw extruder, diameter 40 mm, slit interval A liquid crystal polymer film having a thickness of 75 μm was obtained by extrusion from a 0.6 mm inflation die. The obtained liquid crystal polymer film had a melting point of 280 ° C. and a molecular orientation degree SOR of 1.2. A 200 μm thick aluminum foil (coated body) and the liquid crystal polymer film are overlaid, and the whole is vacuumed to 40 mmHg using a vacuum flat plate heat press from above and below, and thermocompression bonded at a temperature of 275 ° C. and a pressure of 20 kg / cm ^2. Then, the liquid crystal polymer film was peeled off so that a part of it remained.
Thereafter, the aluminum foil was removed by chemical etching, and the molecular orientation SOR of the obtained liquid crystal polymer coat layer was measured. As a result, it was 1.2 and the thickness was 30 μm.
For comparison, the above liquid crystal polymer is melted on the same aluminum foil (coated body) and coated by a roll coater method to obtain a liquid crystal polymer coat layer. As described above, the molecules of the liquid crystal polymer coat layer are obtained. The degree of orientation SOR was measured and found to be 1.5.

[Example 2]
A thermotropic liquid crystal polyester composed of 27 mol% of 6-hydroxy-2-naphthoic acid units and 73 mol% of p-hydroxybenzoic acid units was heated and kneaded at 280-300 [deg.] C. using a single screw extruder, diameter 40 mm, slit interval Extrusion was performed from a 0.6 mm inflation die to obtain a liquid crystal polymer film having a thickness of 20 μm. The obtained liquid crystal polymer film had a melting point of 280 ° C. and a molecular orientation SOR of 1.03.
The above-mentioned liquid crystal polymer film is used as a liquid crystal polymer coat layer material, and is superposed on an electrolytic copper foil (coated body) having a thickness of 18 μm and thermocompression bonded in the same manner as in Example 1 using a vacuum hot press machine. It peeled off so that a part of film might remain, and the liquid crystal polymer coat layer was obtained. The electrolytic copper foil was removed by chemical etching, and the molecular orientation degree SOR and the thickness of the liquid crystal polymer coat layer were measured and found to be 1.03 and 9 μm, respectively.

Example 3
A thermotropic liquid crystal polyester composed of 27 mol% of 6-hydroxy-2-naphthoic acid units and 73 mol% of p-hydroxybenzoic acid units was heated and kneaded at 280-300 [deg.] C. using a single screw extruder, diameter 40 mm, slit interval A liquid crystal polymer film having a thickness of 50 μm was obtained by extrusion from a 0.6 mm inflation die. The obtained liquid crystal polymer film had a melting point of 280 ° C., a molecular orientation SOR of 1.02, and a thermal expansion coefficient of −8 ppm / ° C.
The above liquid crystal polymer film is used as a liquid crystal polymer coat layer material, a rolled copper foil having a thickness of 10 μm and a thermal expansion coefficient of 18 ppm / ° C. is used as a material to be coated, Similarly, after thermocompression bonding, the liquid crystal polymer film was peeled off so that a part of the liquid crystal polymer film remained to obtain a liquid crystal polymer coat layer. When the rolled copper foil was chemically etched and the molecular orientation degree SOR and thickness of the obtained liquid crystal polymer coat layer were measured, they were 1.02 and 15 μm, respectively. The thermal expansion coefficient was −8 ppm / ° C.

Example 4
The coated body having the liquid crystal polymer coating layer obtained in Example 3 was heated to 292 ° C. using a hot air circulation oven. The rolled copper foil was removed by chemical etching. The obtained liquid crystal polymer coat layer had a molecular orientation SOR of 1.02, a thickness of 15 μm, and a thermal expansion coefficient of 18 ppm / ° C.

Example 5
An electrolytic copper foil having a thickness of 18 μm is used as a metal foil on the upper surface, and an electrolytic copper foil having a thickness of 18 μm is used as a metal foil on the lower surface. Between these two metal foils, the same thickness as that used in Example 3 is 50 μm. Using a vacuum flat plate hot press machine, the whole is vacuumed at 30 mmHg and hot pressed at a press temperature of 270 ° C. and a press pressure of 60 kg / cm ² to produce a double-sided metal foil laminate with a thickness of 86 μm. did. The liquid crystal polymer film used here had a molecular orientation SOR of 1.02.
Said double-sided metal foil laminated body was isolate | separated by the center part in the thickness direction on the upper surface side and the lower surface side, and two single-sided metal foil laminated bodies were obtained. The separation surface in the liquid crystal polymer layer was smooth with no fuzz. The thickness of these two single-sided metal foil laminates is 43 μm, and the thickness of the liquid crystal polymer layer is 25 μm if the thickness of the metal foil is 18 μm.
The electrolytic copper foil was removed by chemical etching from the single-sided metal foil laminate thus obtained. The molecular orientation degree SOR of the remaining film-like liquid crystal polymer layer was 1.02, and the degree of molecular orientation did not change.

Example 6
Applying force to peel off the metal foil layer side of the upper surface and the metal foil layer side of the lower surface of the double-sided metal foil laminate having a thickness of 86 μm prepared in Example 5 at a position different from Example 5, The liquid crystal polymer layer was divided into two parts up and down to produce a first laminate composed of the upper metal foil layer and the liquid crystal polymer layer, and a second laminate composed of the lower metal foil layer and the liquid crystal polymer layer. .
The thickness of the first laminate was 48 μm, therefore the thickness of the liquid crystal polymer layer was 30 μm, and the thickness of the second laminate was 38 μm, and thus the thickness of the liquid crystal polymer layer was 20 μm.
The metal foil layers of the first laminate and the second laminate were removed by chemical etching. The molecular orientation degree SOR of the obtained liquid crystal polymer layer was 1.02 for both the first laminate and the second laminate.

Example 7
A thermotropic liquid crystal polyester composed of 27 mol% of 6-hydroxy-2-naphthoic acid units and 73 mol% of p-hydroxybenzoic acid units was heated and kneaded at 280-300 [deg.] C. using a single screw extruder, diameter 40 mm, slit interval A liquid crystal polymer film with a thickness of 16 μm was obtained by extrusion from a 0.6 mm inflation die. The obtained liquid crystal polymer film had a melting point of 280 ° C. and a molecular orientation SOR of 1.02.
The above liquid crystal polymer film having a thickness of 16 μm is sandwiched between two pieces of electrolytic copper foil having a thickness of 18 μm and thermally bonded at a roll temperature of 280 ° C. and a linear pressure of 100 kg / cm using a pair of hot press rolls. A laminate comprising a metal foil layer, a liquid crystal polymer layer, and a metal foil layer on the lower surface was prepared. The thickness of the laminate was 52 μm.
Next, a force was applied so as to peel off the metal foil layer side on the upper surface and the metal foil layer side on the lower surface of the laminate having a thickness of 52 μm, the liquid crystal polymer layer was divided into two parts up and down, and the upper metal foil layer and the liquid crystal A first laminate composed of a polymer layer, and a second laminate composed of a lower metal foil layer and a liquid crystal polymer layer were prepared.
The thickness of the first laminate was 26 μm, therefore the thickness of the liquid crystal polymer layer was 8 μm, and the thickness of the second laminate was also 26 μm, and thus the thickness of the liquid crystal polymer layer was 8 μm.
The metal foil layers of the first laminate and the second laminate were removed by chemical etching. The molecular orientation degree SOR of the obtained liquid crystal polymer layer was 1.02 for both the first laminate and the second laminate.

Example 8
One electrolytic copper foil having a thickness of 18 μm was stacked on the liquid crystal polymer layer side of the 26 μm-thick laminate obtained in Example 7, and thermally bonded in the same manner as in Example 7. A laminate composed of a layer and a metal foil layer on the lower surface was produced. The thickness of the laminated body was 44 μm.
Next, a force was applied so as to peel off the metal foil layer side on the upper surface and the metal foil layer side on the lower surface of the laminate having a thickness of 44 μm, the liquid crystal polymer layer was divided into two parts up and down, and the upper metal foil layer and the liquid crystal A first laminate composed of a polymer layer, and a second laminate composed of a lower metal foil layer and a liquid crystal polymer layer were prepared.
The thickness of the first laminate was 22 μm, and therefore the thickness of the liquid crystal polymer layer was 4 μm, and the thickness of the second laminate was 22 μm, and thus the thickness of the liquid crystal polymer layer was 4 μm.
The metal foil layers of the first laminate and the second laminate were removed by chemical etching. The molecular orientation degree SOR of the obtained liquid crystal polymer layer was 1.02 for both the first laminate 1 and the second laminate.

Example 9
One electrolytic copper foil having a thickness of 18 μm was stacked on the liquid crystal polymer layer side of the laminate having a thickness of 22 μm obtained in Example 8, and heat bonding was performed at a press temperature of 294 ° C. and a pressure of 20 kg / cm ² using a hot press machine. And the laminated body comprised by the metal foil layer of an upper surface, a liquid crystal polymer layer, and the metal foil layer of a lower surface was produced. The thickness of the laminated body was 40 μm. The metal foil layer of the laminate was etched to form a circuit in a range of 15 × 15 mm square, and the circuit was heat-fixed and attached to a semiconductor chip to produce a mounting circuit board.

Example 10
One electrolytic copper foil having a thickness of 18 μm is stacked on the liquid crystal polymer layer side of the laminate having a thickness of 22 μm obtained in Example 8 and heated at a press temperature of 294 ° C. and a pressure of 20 kg / cm ² using a hot press machine. Two laminates composed of a metal foil layer on the upper surface, a liquid crystal polymer layer, and a metal foil layer on the lower surface were produced by bonding. The thickness of the laminated body was 40 μm. A circuit pattern was formed by etching on the two metal foils of the laminate having a thickness of 40 μm produced in this way. Between the laminate on which the two circuit patterns are formed, a liquid crystal polymer film having the same thickness of 50 μm as that used in Example 3 is sandwiched and hot pressed at a pressing temperature of 284 ° C. and a pressure of 10 kg / cm ^2. Multi-layered. Next, after a through hole was made by a drill at the position of the connection portion in the circuit pattern, a plated through hole portion was formed by a Crimson electroless copper plating method to produce a multilayer circuit board.

(A)-(c) is explanatory drawing which shows the coating method using the isotropic liquid crystal polymer film which concerns on 1st Embodiment of this invention. (A)-(g) is explanatory drawing which shows the manufacturing method of the single-sided metal foil laminated body which concerns on 2nd Embodiment of this invention. It is a front view of the manufacturing apparatus of the single-sided metal foil laminated body of this invention. It is a conceptual diagram which shows the mounting circuit board which concerns on 3rd Embodiment of this invention. It is a section schematic diagram of the multilayer mounting circuit board concerning a 4th embodiment of the present invention. It is a schematic side view which shows the measuring machine of a molecular orientation degree.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Coated body, 2, 2a, 2b ... Liquid crystal polymer film, 3, 3a ... Coated body, 11, 11c ... Double-sided metal foil laminated body, 11a, 11b, 11d, 11e ... Single-sided metal foil laminated body, 12 ... Mounting Circuit board, 14 ... multilayer circuit board, 21 ... heat press device, 23 ... dividing device.

Claims (16)

  A film formed from a polymer capable of forming an optically anisotropic melt phase and having a molecular orientation of 1.3 or less is thermocompression bonded to the coated body, and then a thin layer of the film is left on the coated body. And a coating method, wherein the film is peeled off.   A coated body having a coating layer left on the coated body obtained by the coating method according to claim 1.   The coated body according to claim 2, wherein the thickness of the coating layer is 15 µm or less.   A coated body having a polymer coating layer capable of forming an optically anisotropic melt phase having a thickness of 15 μm or less and a coated body, wherein the molecular orientation of the polymer layer is 1.3 or less.   5. The coated body according to claim 2, wherein a thermal expansion coefficient of the coat layer is equal to a thermal expansion coefficient of the body to be coated.   A double-sided metal foil laminate comprising a polymer layer capable of forming an optically anisotropic melt phase, a metal foil layer on the upper surface thereof, and a metal foil layer on the lower surface thereof, and the upper and lower surfaces in the thickness direction of the polymer layer. A first single-sided metal foil laminate comprising a polymer layer capable of forming an optically anisotropic molten phase and a metal foil layer on the upper surface thereof, and an optically anisotropic molten phase is formed. A method for producing a single-sided metal foil laminate, comprising: dividing into a second single-sided metal foil laminate comprising a polymer layer and a metal foil layer on a lower surface thereof.   7. The double-sided metal foil laminate according to claim 6, wherein a film formed from a polymer capable of forming an optically anisotropic melt phase is sandwiched between two metal foils in a layered form, and is hot-pressed. The manufacturing method of the single-sided metal foil laminated body characterized by the above-mentioned.   The single-sided metal foil laminated body obtained by the manufacturing method in any one of Claim 6 or 7.   9. The single-sided metal foil laminate according to claim 8, wherein the polymer layer capable of forming the optically anisotropic molten phase of the single-sided metal foil laminate is 15 μm or less.   The single-sided metal foil laminate according to claim 8 or 9, wherein the polymer layer capable of forming the optically anisotropic melt phase has a molecular orientation of 1.3 or less.   It consists of a polymer layer capable of forming an optically anisotropic melt phase having a thickness of 15 μm or less and a metal foil layer bonded to one surface thereof, and the molecular orientation of the polymer layer is 1.3 or less. Single-sided metal foil laminate.   The mounting circuit board formed by mounting and connecting an electronic component on the laminated body using the single-sided metal foil laminated body according to claim 8.   A multi-layer laminate in which this laminate or another laminate is superposed on the single-sided metal foil laminate according to any one of claims 8 to 11, and an electronic component is mounted and connected on the multi-layer laminate. A multilayer mounting circuit board.   The double-sided metal, wherein the double-sided metal foil laminate is produced by superposing and heating the metal foil on the polymer layer side of the single-sided metal foil laminate according to any one of claims 8 to 11. Manufacturing method of foil laminated body.   The double-sided metal foil laminated body obtained by the manufacturing method of Claim 14. A hot press apparatus for hot pressing a film formed from a polymer that can form an optically anisotropic melt phase sandwiched between two metal foils in a thickness direction;
A double-sided metal foil laminate comprising a polymer layer capable of forming an optically anisotropic melt phase formed by hot pressing, a metal foil layer on the upper surface thereof, and a metal foil layer on the lower surface thereof is formed by the thickness of the polymer layer. The manufacturing apparatus of the single-sided metal foil laminated body provided with the division | segmentation apparatus torn to an upper surface and a lower surface in a length direction.

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