JP2003069237A - Insulation film and multilayer interconnection board using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that in insulation films made of organic materials and a multiplayer interconnection board using the same, the increased density of its wirings, its insulating quality, the reliability of its continuity, and its high-frequency transmission characteristic cannot be satisfied collectively. SOLUTION: The multiplayer interconnection board 6 comprises a plurality of insulation films 3 and a plurality of wiring conductors 4 made of metallic foils each of which is provided on at least one of the upper and lower surfaces of the film 3. Each insulation film 3 comprises a liquid crystal polymer layer 1 wherein its contact angle with triallylisocyanurate is 3-5 deg. and its surface energy is 45-70 mJ/m<2> , and coating layers 2 made of polyphenylene ether-based organic matters which are formed on the upper and lower surfaces of the layer 1. Further, each through conductor 5 formed in each insulation film 3 is provided electrically connectively between the wiring conductors 4 so positioned on the upper and lower sides of each film 3 as to sandwich each film 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating film used in various kinds of electronic equipment such as AV equipment, home electric appliances, communication equipment, computers and peripheral equipment thereof, and a multilayer wiring board using the same, and particularly to a liquid crystal polymer. The present invention relates to an insulating film used in part and a multilayer wiring board using the same.

[0002]

2. Description of the Related Art Conventionally, a multilayer wiring board for forming a hybrid integrated circuit in which a large number of active components such as semiconductor elements and passive components such as capacitance elements and resistance elements are mounted to form a predetermined electronic circuit is usually Formed by stacking a number of wiring boards, each having a plurality of wiring conductors formed inside the through hole and on the surface of the insulating layer by forming through holes in the insulating film made of glass cloth impregnated with epoxy resin by a drill. ing.

In general, current electronic devices are required to be small, thin, lightweight, high-performance, high-performance, high-quality and highly reliable, as represented by mobile communication devices. Electronic components such as hybrid integrated circuits mounted on
There is a demand for higher densities, and in order to meet such demands for higher densities, the multilayer wiring boards that compose electronic components are also made finer in wiring conductors and thinner in insulating layers.
The miniaturization of through holes has become necessary. For this reason, in recent years, in order to miniaturize the through holes, laser machining, which enables finer machining than drilling, has come to be used.

However, the insulating film formed by impregnating glass cloth with an epoxy resin has a limit in miniaturizing the through holes because it is difficult to drill the glass cloth with a laser, and the glass cloth of There is a problem that it is difficult to form a through hole having a uniform hole diameter due to the uneven thickness.

In order to solve these problems, an insulating film formed by impregnating a non-woven fabric made of aramid resin fiber with an epoxy resin or an insulating film formed by coating a polyimide film with an epoxy adhesive is used as an insulating layer. The multilayer wiring board used for is proposed.

However, an insulating film using an aramid non-woven fabric or a polyimide film has a high hygroscopic property, and when solder reflow is performed in a moisture-absorbed state, moisture absorbed by the solder reflow is vaporized to generate a gas, and the insulating layers are separated. There was a problem such as peeling.

In order to solve such a problem, it has been studied to use a liquid crystal polymer as a material for an insulating layer of a multilayer wiring board. The layer made of liquid crystal polymer is composed of rigid molecules and also has a structure in which the molecules are regularly arranged to some extent, and the intermolecular force is strong.
Shows high heat resistance, high elastic modulus, high dimensional stability and low moisture absorption,
It is characterized in that it does not require the use of a reinforcing material such as glass cloth and is excellent in fine workability. Further, even in a high frequency region, it has a characteristic that it has a low dielectric constant and a low dielectric loss tangent and is excellent in high frequency characteristics.

Utilizing the characteristics of such a liquid crystal polymer,
JP-A-8-97565 discloses that a circuit layer contains a first liquid crystal polymer, and an adhesive layer containing a second liquid crystal polymer having a melting point lower than that of the first liquid crystal polymer is inserted between the circuit layers. Has been proposed, and in JP-A-2000-269616, there is proposed a high-frequency circuit board formed by adhering a thermoplastic liquid crystal polymer film and a metal foil with an epoxy adhesive. Has been done.

[0009]

SUMMARY OF THE INVENTION
The multilayer printed circuit board proposed in 8-97565 is
When an adhesive layer containing a liquid crystal polymer is inserted between circuit layers and they are bonded by thermocompression bonding, the liquid crystal polymer molecules are rigid and molecules are regularly oriented to some extent to strengthen the intermolecular force. Of the liquid crystal polymer of the circuit layer and the liquid crystal polymer of the adhesive layer can be entangled with only a small part of the molecules, resulting in poor adhesion and peeling between layers in a high temperature bias test, resulting in insulation failure. There was a problem that it would occur. Also, when the conductor foil of the circuit layer and the liquid crystal polymer are bonded by heat fusion, the liquid crystal polymer molecules are difficult to move and therefore cannot enter the minute recesses on the conductor foil surface, resulting in sufficient anchoring effect. However, the adhesiveness between the conductor foil and the liquid crystal polymer deteriorates, and there is a problem that the conductor foil peels off between the two under high temperature and high humidity and the conductor foil is broken.

In the high frequency circuit board proposed in Japanese Patent Laid-Open No. 2000-269616, since the dielectric constant of the epoxy adhesive is greatly different from the dielectric constant of the liquid crystal polymer, a slight thickness caused by pressurization during lamination is required. Due to the variation, there is a problem that the transmission characteristic is deteriorated in a high frequency region, particularly in a frequency region of 100 MHz or more.

The present invention has been devised in view of the above problems of the prior art, and an object thereof is to provide an insulating film excellent in insulation, conduction reliability, and high frequency transmission characteristics, and a multilayer wiring board using the same. It is in providing.

[0012]

The insulating film of the present invention has a contact angle with triallyl isocyanurate of 3 to 50 °.
In addition, a coating layer made of a polyphenylene ether organic material is formed on the upper and lower surfaces of the liquid crystal polymer layer having a surface energy of 45 to 70 mJ / m ² .

Further, the insulating film of the present invention has the above-mentioned structure, and the center line surface roughness Ra of the upper and lower surfaces of the liquid crystal polymer layer.
Is 0.05 to 5 μm.

Further, the insulating film of the present invention is characterized in that, in the above constitution, the polyphenylene ether organic substance is a thermosetting polyphenylene ether.

The multilayer wiring board of the present invention is formed by laminating a plurality of the above-mentioned insulating films having wiring conductors made of a metal foil disposed on at least one of the upper and lower surfaces thereof.
It is characterized in that the wiring conductors located above and below the insulating film are electrically connected to each other via a through conductor formed in the insulating film.

According to the insulating film of the present invention, polyphenylene ether is formed on the upper and lower surfaces of a liquid crystal polymer layer having a contact angle with triallyl isocyanurate of 3 to 50 ° and a surface energy of 45 to 70 mJ / m ^2. Since the coating layer is formed of a system organic substance, the coating layer spreads well on the upper and lower surfaces of the liquid crystal polymer layer, and the activated molecular layer and the coating layer on the surface of the liquid crystal polymer layer are relatively easily moved by heat. And satisfactorily entangle and bond with each other, and as a result, an insulating film that does not separate between the two even in a high temperature bias test can be obtained. In addition, since the polyphenylene ether-based organic molecule is not as rigid as the liquid crystal polymer molecule, and the molecule does not move easily because it does not show a regular orientation, as a result, even when the insulating films are multilayered, Adhesion is good, and there is no possibility that insulation failure occurs due to peeling between films in a high temperature bias test. further,
Even when the wiring conductor is arranged on the surface of the insulating film, the polyphenylene ether-based organic compound molecules can enter the fine recesses on the surface of the wiring conductor to exert a sufficient anchoring effect, and the adhesion between the insulating film and the wiring conductor can be improved. The result is good, and as a result, there is no possibility that the wiring conductor is broken due to peeling between the two under high temperature and high humidity. In addition, since the frequency behavior of the dielectric constant of the coating layer made of polyphenylene ether-based organic material and the liquid crystal polymer layer are almost the same, even if a slight thickness variation occurs in the coating layer due to pressure when bonding the wiring conductor, It is possible to obtain an insulating film excellent in high-frequency transmission characteristics without causing deterioration in transmission characteristics in a region.

Further, according to the insulating film of the present invention, in the above structure, the center line surface roughness Ra of the upper and lower surfaces of the liquid crystal polymer layer is 0.05 to 5 μm, so that the upper and lower surfaces of the liquid crystal polymer layer are polyphenylene ether type. The coating layer made of an organic substance has a good anchoring effect and good adhesiveness, and an insulating film in which the liquid crystal polymer layer and the coating layer are more firmly adhered can be obtained.

Further, according to the insulating film of the present invention,
In the above configuration, since the polyphenylene ether-based organic material is a thermosetting polyphenylene ether, the thermosetting polyphenylene ether is excellent in heat resistance and dimensional stability, as a result, excellent in temperature cycle reliability, and the wiring conductor It is possible to obtain an insulating film having good positional accuracy when bonding.

Further, according to the multilayer wiring board of the present invention, since the multilayer wiring board is formed by using the above-mentioned insulating film, the multilayer wiring board is excellent in moisture resistance, continuity reliability and high frequency transmission characteristics. You can

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the insulating film and the multilayer wiring board of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an example of an embodiment of the insulating film of the present invention, and FIG. 2 is a semiconductor device on a multilayer wiring board of the present invention formed by using the insulating film of FIG. FIG. 3 is a cross-sectional view showing an example of an embodiment of a hybrid integrated circuit in which electronic components such as the above are mounted. Furthermore, FIG.
FIG. 3 is an enlarged cross-sectional view of a main part of the multilayer wiring board shown in FIG. 2. In these figures, 1 is a liquid crystal polymer layer, 2 is a coating layer made of a polyphenylene ether organic material, and these mainly constitute the insulating film 3 of the present invention. Further, 4 is a wiring conductor, 5 is a penetrating conductor, 7 is an electronic component such as a semiconductor element, and the multilayer wiring board 6 of the present invention is mainly composed of the insulating film 3, the wiring conductor 4, and the penetrating conductor 5. In addition, the multilayer wiring board 6 of this example is shown as being formed by laminating four layers of the insulating films 3.

The insulating film 3 includes the liquid crystal polymer layer 1 and
A coating layer 2 made of a polyphenylene ether-based organic material is formed on the upper and lower surfaces thereof, and when a multilayer wiring board 6 is formed using this, it is mounted on the wiring conductor 4 or the multilayer wiring board 6. It has a function as a support for the electronic component 7.

Here, the liquid crystal polymer refers to a polymer having a property of being in a liquid crystal state or optically birefringent when melted, and generally, a lyotropic liquid crystal polymer which exhibits liquid crystallinity in a solution state or a thermotropic liquid crystallinity which exhibits liquid crystallinity when melted. A liquid crystal polymer or a liquid crystal polymer of type 1, type 2, and type 3 classified by heat distortion temperature is included, and the liquid crystal polymer used in the present invention includes temperature cycle reliability, solder heat resistance, and processability. From the viewpoint of 200 ~ 400 ℃
Those having a melting point at the above temperature, particularly at a temperature of 250 to 350 ° C. are preferable. In addition, the polyphenylene ether-based organic matter,
It means a polyphenylene ether resin, a resin in which various functional groups are bonded to polyphenylene ether, or a derivative or polymer thereof.

The liquid crystal polymer layer 1 comprises an antioxidant for improving thermal stability, a light stabilizer such as an ultraviolet absorber for improving light resistance, and a flame retardant within a range that does not impair the physical properties of the layer. Halogen- or phosphoric acid-based flame retardants to add properties, antimony compounds and flame-retardant aids such as zinc borate, barium metaborate and zirconium oxide, higher fatty acids and higher grades to improve lubricity Fatty acid ester
Lubricants such as higher fatty acid metal salts and fluorocarbon-based surfactants, aluminum oxide, silicon oxide for adjusting the thermal expansion coefficient and / or improving mechanical strength
Titanium oxide, barium oxide, strontium oxide, zirconium oxide, calcium oxide, zeolite, silicon nitride, aluminum nitride, silicon carbide, potassium titanate, barium titanate, strontium titanate, calcium titanate, aluminum borate, barium stannate A filler such as barium zirconate or strontium zirconate may be contained.

The particle shape of the above-mentioned filler and the like may be substantially spherical, needle-like, flake-like, etc. From the viewpoint of filling properties, substantially spherical shape is preferred. The particle diameter is usually about 0.1 to 15 μm, which is smaller than the thickness of the liquid crystal polymer layer 1.

The liquid crystal polymer layer 1 is subjected to buff polishing, blast polishing, brush polishing, plasma treatment, corona treatment, ultraviolet treatment, chemical treatment, etc. on its surface in order to improve the adhesion to the coating layer 2. It is important to use the method so that the contact angle with triallyl isocyanurate is 3 to 50 ° and the surface energy is 45 to 70 mJ / m ² .

The wettability of liquid triallyl isocyanurate to the liquid crystal polymer layer 1 is similar to the wettability of polyphenylene ether to the liquid crystal polymer layer 1,
By making the upper and lower surfaces of the liquid crystal polymer layer 1 have a contact angle with triallyl isocyanurate of 3 to 50 °, the coating layer 2 satisfactorily wets and spreads on the upper and lower surfaces of the liquid crystal polymer layer 1, and the liquid crystal polymer layer 1 and the coating layer. Adhesion with 2 can be made good, and as a result, it is possible to obtain an insulating film 3 which does not peel off between the two even in a high temperature bias test.
When the contact angle with triallyl isocyanurate is smaller than 3 °, the coating layer 2 spreads extremely over the liquid crystal polymer layer 1 and the positional accuracy deteriorates, and a plurality of insulating films 3 are stacked and heated. When applying pressure to make multiple layers,
The wiring conductors 4 formed on the surface of the insulating film 3 and the penetrating conductors 5 formed inside tend to be displaced and easily break. If the angle exceeds 50 °, the liquid crystal polymer layer 1 and the coating layer are subjected to a high temperature bias test. There is a tendency that the adhesiveness with No. 2 decreases and peeling easily occurs between the two. In addition, the liquid crystal polymer layer 1
By setting the surface energy of the upper and lower surfaces to 45 to 70 mJ / m ² , the activated molecular layer on the surface of the liquid crystal polymer layer 1 which is relatively easily moved by heat and the coating layer are well entangled and bonded to each other. The adhesion can be made even stronger. If the surface energy is less than 45 mJ / m ² ,
The molecular layer on the surface of the liquid crystal polymer layer 1 is not sufficiently activated,
It tends to be difficult to entangle and bond well with the coating layer 2, and if it exceeds 70 mJ / m ² , the surface of the liquid crystal polymer layer 1 becomes very reactive and reacts with oxygen in the air to A weak oxide is formed on the surface, resulting in
The adhesiveness between the liquid crystal polymer layer 1 and the coating layer 2 tends to decrease, and the liquid crystal polymer layer 1 and the coating layer 2 tend to peel off from each other. Therefore, it is preferable that the contact angle between the upper and lower surfaces of the liquid crystal polymer layer 1 and the triallyl isocyanurate is 3 to 50 ° and the surface energy of the liquid crystal polymer layer 1 is 45 to 70 mJ / m ² .

The term surface energy as used herein means the dictionary of physics and chemistry (3rd edition, augmented edition) [Bunichi Tamamushi et al., Iwanami Shoten (1981).
Year)], it means the sum of the latent heat of the surface and the surface tension, and the measuring method thereof can be quantified by a wetting index standard liquid commercially available from Nacalai Tesque, Inc., for example. . This wetting index standard solution is prepared by adjusting the wetting index standard solution for each surface energy based on the wettability on the surface of the reference substance such as Teflon (registered trademark). The surface energy on the sample surface is quantified by dropping the sample on the sample surface and evaluating the spread diameter of the droplet and / or the contact angle of the droplet in a predetermined time.

The center line surface roughness Ra of the surface of the liquid crystal polymer layer 1 is preferably 0.05 to 5 μm. According to the insulating film of the present invention, the center line surface roughness Ra of the upper and lower surfaces of the liquid crystal polymer layer 1 is set to 0.05 to 5 μm, so that the upper and lower surfaces of the liquid crystal polymer layer 1 have a good anchoring effect with the coating layer 2. The adhesiveness is good, and the liquid crystal polymer layer 1 and the coating layer 2 can be more firmly adhered.

The center line surface roughness Ra is preferably 0.05 μm or more from the viewpoint of preventing separation of the liquid crystal polymer layer 1 and the coating layer 2 during solder reflow, and the coating layer 2 on the surface. The thickness is preferably 5 μm or less from the viewpoint of preventing the entrapment of air when forming the film. Therefore, the liquid crystal polymer layer 1 preferably has a center line surface roughness Ra of the surface of 0.05 to 5 μm.

Next, the coating layer 2 has a function as an adhesive when the wiring conductor 4 to be described later is adhered and formed, and when the insulating film 3 is used to form the multilayer wiring board 6, the insulating film 3 is used. It plays the role of an adhesive when laminating each other.

The coating layer 2 contains 30 to 90% by volume of a polyphenylene ether resin, a derivative thereof, or a polyphenylene ether organic material such as a polymer alloy of these, and particularly, the thermal cycle reliability and the adhesion of the wiring conductor 4 to each other. From the viewpoint of positional accuracy in this case, it is preferable to contain a thermosetting polyphenylene ether such as allyl-modified polyphenylene ether.

When the content of the polyphenylene ether-based organic substance is less than 30% by volume, the kneading property with the filler described below tends to be lowered, and when it exceeds 90% by volume, the surface of the liquid crystal polymer layer 1 is When forming the coating layer 2 on
The thickness variation of the coating layer 2 tends to increase. Therefore, the content of polyphenylene ether-based organic matter,
A range of 30 to 90% by volume is preferable.

From the viewpoint of improving the adhesiveness with the liquid crystal polymer layer 1 and the adhesiveness with the wiring conductor 4 and the through conductor 5 described later, the coating layer 2 has two functional groups capable of undergoing a polymerization reaction. It is preferable to contain an additive such as a polyfunctional monomer or a polyfunctional polymer having the above, and for example, it is preferable to contain triallyl isocyanurate, triallyl cyanurate, or a polymer thereof.

Further, the coating layer 2 comprises a rubber component for adjusting the elastic modulus and an antioxidant for improving the thermal stability,
Light stabilizers such as UV absorbers to improve light resistance, halogen-based or phosphoric acid-based flame retardants to add flame retardancy, antimony compounds, zinc borate, barium metaborate, and zirconium oxide. Flame retardant aids such as, lubricants such as higher fatty acids and higher fatty acid esters to improve lubricity, higher fatty acid metal salts and fluorocarbon surfactants,
Aluminum oxide, silicon oxide, titanium oxide, barium oxide, strontium oxide, zirconium oxide, calcium oxide, zeolite, silicon nitride, aluminum nitride, silicon carbide, potassium titanate for adjusting thermal expansion coefficient and improving mechanical strength・ Filling materials such as barium titanate, strontium titanate, calcium titanate, aluminum borate, barium stannate, barium zirconate, strontium zirconate, etc., or improving their bondability and mechanical properties. A coupling agent such as a silane coupling agent or a titanate coupling agent for increasing the mechanical strength may be contained.

Particularly, when the insulating film 3 is laminated and pressed to form the multilayer wiring substrate 6, the fluidity of the coating layer 2 is suppressed, and the displacement of the through conductor 5 and the variation in the thickness of the coating layer 2 are prevented. From the viewpoint, the coating layer 2 is used as a filler.
It is preferable to contain the inorganic insulating powder in a volume% or more.
In addition, the adhesive interface with the liquid crystal polymer layer 1 and the wiring conductor 4
The content of the filler is preferably 70% by volume or less from the viewpoint of preventing peeling during solder reflow at the adhesive interface with. Therefore, it is preferable that the coating layer 2 made of a polyphenylene ether-based organic material contains 10 to 70% by volume of the filler.

The shape of the above-mentioned filling material is substantially spherical.
There are needle-like shapes and flake-like shapes, and a substantially spherical shape is preferable from the viewpoint of filling properties. The particle size is about 0.1 to 15 μm, which is smaller than the thickness of the coating layer 2.

Such an insulating film 3 is obtained by adding a thermosetting polyphenylene ether resin and a solvent, a plasticizer, a dispersant, etc. to an inorganic insulating powder such as silicon oxide having a particle size of about 0.1 to 15 μm. Conventionally well-known on the upper and lower surfaces of the liquid crystal polymer layer 1 which has been subjected to surface treatment by plasma treatment so that the contact angle with triallyl isocyanurate is 3 to 50 ° and the surface energy is 45 to 70 mJ / m ^2. The coating layer 2 is formed on the surface of the liquid crystal polymer layer 1 after forming the coating layer 2 by using a sheet molding method such as the doctor blade method or by immersing the liquid crystal polymer layer 1 in the above paste and pulling it up vertically. After forming this, 60 ~
It is manufactured by heating and drying at a temperature of 100 ° C for 5 minutes to 3 hours.

The thickness of the insulating film 3 is preferably 10 to 200 μm from the viewpoint of ensuring insulation reliability, and from the viewpoint of ensuring high heat resistance, low hygroscopicity and high dimensional stability. It is preferable that the thickness of the liquid crystal polymer layer 1 be within the range of 40 to 90% of the thickness of the insulating film 3.

Next, the multilayer wiring board 6 of the present invention is formed by laminating a plurality of insulating films 3 each having a wiring conductor 4 made of a metal foil disposed on at least one of the upper and lower surfaces thereof.
Wiring conductors 4 located above and below with the insulating film 3 interposed therebetween
It is formed by electrically connecting the gaps through the penetrating conductors 5 formed on the insulating film 3.

The wiring conductor 4 has a thickness of 2 to 30 μm and is made of a metal foil having good conductivity such as copper or gold. The electronic component 7 mounted on the multilayer wiring board 6 is connected to an external electric circuit (not shown). It has a function of electrically connecting.

Such a wiring conductor 4 is composed of the insulating film 3
From the viewpoint of preventing voids from being generated around the wiring conductor 4 when a plurality of layers are laminated, as shown in the enlarged cross-sectional view of the main part of FIG. 3, the coating layer 2 includes at least the surface of the wiring conductor 4 and the coating layer. It is preferable that the second surface and the second surface are buried so as to be flat. When the wiring conductor 4 is embedded in the coating layer 2, the porosity of the coating layer 2 in the dry state is 3 to 40% by volume.
If so, the coating layer 2 around the wiring conductor 4 can be flattened without causing resin swelling, and the air trapped between the wiring conductor 4 and the coating layer 2 can be easily discharged to prevent entrapment of air bubbles. can do. When the porosity in the dry state exceeds 40% by volume, pores remain in the coating layer 2 after pressurizing and heating and curing a plurality of laminated insulating films 3, and the pores adsorb moisture in the air. Therefore, it is preferable that the porosity of the coating layer 2 in the dry state is in the range of 3 to 40% by volume because the insulating property may be deteriorated.

The porosity of the coating layer 2 in the dry state is appropriately adjusted by adjusting the drying conditions such as the drying temperature and the temperature rising rate when the coating layer 2 is applied on the surface of the liquid crystal polymer layer 1 and dried. By doing so, a desired value can be obtained.

Furthermore, the cross-sectional shape in the width direction of the wiring conductor 4 arranged on the insulating film 3 is a trapezoidal shape in which the length of the bottom side on the insulating film 3 side is shorter than the length of the opposite bottom side, and the insulating film is formed. The angle between the bottom side and the side on the 3 side is
It is preferably set to 95 to 150 °. The cross-sectional shape of the wiring conductor 4 disposed on the insulating film 3 in the width direction is a trapezoid whose base length on the insulating film 3 side is shorter than the length of the opposing base, and By setting the angle formed by the sides with 95 to 150 °, the wiring conductor 4
When the wiring conductor 4 is embedded in the coating layer 2, the wiring conductor 4 can be easily embedded in the coating layer 2 so that the surface of the coating layer 2 after the wiring conductor 4 is embedded can be made substantially flat. It is possible to obtain the multilayer wiring board 6 that does not bite into and deteriorate the insulation. From the viewpoint of embedding air bubbles without biting, it is preferable that the angle formed by the bottom side and the side side of the insulating film 3 side be 95 ° or more.
From the viewpoint of miniaturization, it is preferable that the angle be 150 ° or less.

In addition, the thickness x (μm) of the covering layer 2 located between the short base of the wiring conductor 4 and the liquid crystal polymer layer 1 between the insulating film 3 is between the upper and lower liquid crystal polymer layers 1. Is T (μm), and the thickness of the wiring conductor 4 is t
(Μm), 3 μm ≦ 0.5T−t ≦ x ≦ 0.5T
≦ 35 μm (however, 8 μm ≦ T ≦ 70 μm, 1 μm ≦ t ≦
32 μm) is preferable.

The distance between the liquid crystal polymer layers 1 is T (μm),
Assuming that the thickness of the wiring conductor 4 is t (μm), the thickness x (μ of the coating layer 2 made of polyphenylene ether organic material between the bottom of the wiring conductor 4 and the liquid crystal polymer layer 1 is short.
m) is 3 μm ≦ 0.5T−t ≦ x ≦ 0.5T ≦ 35 μm, the distance between the short bottom of the wiring conductor 4 and the liquid crystal polymer layer 1 and the long bottom of the wiring conductor 4 are adjacent to each other. It is possible to reduce the difference in distance between the liquid crystal polymer layers 1 to be less than t (μm), and it is possible to prevent warpage of the multilayer wiring board 6 caused by a large difference in the thickness of the coating layer 2. Therefore, the thickness x of the coating layer 2, which is located between the trapezoidal upper bottom surface of the wiring conductor 4 and the liquid crystal polymer layer 1,
(Μm), the distance between the liquid crystal polymer layers 1 is T (μm),
When the thickness of the wiring conductor 4 is t (μm), 3 μm ≦
It is preferable that 0.5T−t ≦ x ≦ 0.5T ≦ 35 μm.

Such a wiring conductor 4 is composed of the insulating film 3
It is formed by depositing a metal foil made of, for example, copper, which is patterned by a subtractive method using a known photoresist, on the precursor sheet to be formed by a transfer method or the like. First, a metal foil transfer film is prepared by adhering a metal foil made of copper on a film serving as a support through an adhesive, and then a metal foil on the film is subjected to a subtractive method using a known photoresist. Is used to etch in a pattern. At this time, the side surface on the surface side of the pattern is more likely to be etched because the side surface on the surface side is in contact with the etching solution for a longer time than the side surface on the film side, and the cross-sectional shape in the width direction of the pattern can be trapezoidal. In addition,
The trapezoidal shape allows the angle between the short base and the side to be adjusted to 95 ~ by adjusting the concentration of the etching solution and the etching time.
It can be trapezoidal at 150 °. Then, this metal foil transfer film is laminated on a precursor sheet which becomes the insulating film 3, and hot pressed for 10 minutes to 1 hour under the conditions of a temperature of 100 to 200 ° C. and a pressure of 0.5 to 10 MPa, and then becomes a support. By removing the film by peeling and transferring the metal foil onto the surface of the precursor sheet which becomes the insulating film 3, the wiring conductor 4 having the trapezoidal upper bottom side embedded in the coating layer 2 can be formed.

The thickness x (μm) of the coating layer 2 between the liquid crystal polymer layers 1 opposed to the short base of the wiring conductor 4 is as follows.
Can be set to a desired range by adjusting the pressure of the hot press at the time of transferring the metal foil. Further, in order to improve the adhesion with the coating layer 2, the surface of the wiring conductor 4 is preferably roughened by a treatment such as buffing, blasting, brushing, or chemical treatment.

The insulating film 3 has a diameter of 20 to 15
The through conductor 5 having a thickness of about 0 μm is formed. Through conductor 5
Are the wiring conductors 4 located above and below with the insulating film 3 in between.
Has a function of electrically connecting to each other. After a through hole is formed by performing a drilling process on the insulating film 3 with a laser, a conductive paste made of copper, silver, gold, solder or the like is conventionally provided in the through hole. It is formed by embedding by a known screen printing method.

According to the multilayer wiring board 6 of the present invention, since the insulating film 3 has the coating layers 2 made of polyphenylene ether organic material on the upper and lower surfaces of the liquid crystal polymer layer 1, the liquid crystal polymer layer 1 has a high quality. It has heat resistance, high elastic modulus, high dimensional stability, and low hygroscopicity, and it is possible to configure the insulating film 3 without using a reinforcing material such as glass cloth. As a result, laser drilling is easy. Therefore, fine and uniform through holes can be formed.

In such a multilayer wiring board 6, a through conductor 5 is formed at a desired position on a precursor sheet to be the insulating film 3 manufactured by the above-described method, and then a patterned metal foil of copper, for example, is formed. , The temperature is 100-200 ℃ and the pressure is 0.
Transfer by hot pressing for 10 minutes to 1 hour under the condition of 5 to 10 MPa, stacking these, and finally hot pressing under the condition of temperature of 150 to 300 ° C and pressure of 0.5 to 10 MPa for 30 minutes to 24 hours. It is manufactured by being completely cured.

According to the multilayer wiring board 6 of the present invention, a plurality of insulating films 3 each having a coating layer 2 made of a polyphenylene ether type organic material formed on the upper and lower surfaces of the liquid crystal polymer layer 1 are laminated. Polyphenylene ether-based organic molecules are not as rigid as liquid-crystal polymer-based organic molecules, and because they do not show regular orientation, the molecules move relatively easily, so they enter the minute recesses on the surface of the wiring conductor 4 and exert a sufficient anchoring effect. You can
As a result, the adhesion between the insulating film 3 and the wiring conductor 4 is improved, and peeling between the two does not occur under high temperature and high humidity. Further, since the frequency behavior of the permittivity of the coating layer 2 made of a polyphenylene ether-based organic material and the liquid crystal polymer layer 1 are substantially equal to each other, a slight thickness variation occurs in the coating layer 2 due to the pressure applied when the wiring conductor 4 is bonded. Even in this case, it is possible to obtain the multilayer wiring board 6 excellent in the high frequency transmission characteristics without causing the deterioration of the transmission characteristics in the high frequency region. Furthermore, when the insulating film 3 is multilayered, since the polyphenylene ether-based organic molecule is easily moved, the polyphenylene ether-based organic molecule is easily entangled with each other, and the adhesion between the coating layers 2 is increased,
As a result, even under the high temperature bias test, the insulating films 3 are not peeled from each other to cause insulation failure.

Thus, according to the multilayer wiring board 6 of the present invention, the semiconductor element is connected to the connection pad 8 formed by a part of the wiring conductor 4 formed on the upper surface of the multilayer wiring board 6 having the above-mentioned structure, through the conductor bump 8 such as solder. And the like electronic components 7 are electrically connected, and at the same time, a conductor bump 9 such as solder is attached to the connection pad 8 formed of a part of the wiring conductor 4 formed on the lower surface of the multilayer wiring board 6.
By forming the above, it is possible to obtain a hybrid integrated circuit having a high wiring density and an excellent insulating property.

The multilayer wiring board 6 of the present invention is not limited to the above-mentioned embodiments, but various modifications can be made without departing from the scope of the present invention. Then, the multilayer wiring board 6 is manufactured by laminating the four layers of the insulating films 3, but the multilayer wiring board 6 may be manufactured by laminating the insulating films 3 of two layers, three layers, or five layers or more. Further, a build-up layer or a solder resist layer 10 made of an insulating layer containing one, two, or three or more layers of an organic resin as a main component may be formed on the upper and lower surfaces of the multilayer wiring board 6 of the present invention. .

[0055]

EXAMPLES Next, the following samples were manufactured and evaluated for the insulating film and the multilayer wiring board of the present invention. (Example) First, spherical fused silica having an average particle size of 0.6 μm was added to a thermosetting polyphenylene ether resin in an amount of 4
Toluene as a solvent and a catalyst for accelerating the curing of the organic resin were further added to 0% by volume, and mixed for 1 hour to prepare a varnish. Then the melting point
The surface of the liquid crystal polymer layer having a thickness of 35 μm at 320 ° C. was set to a voltage of 27 kV, the atmosphere was set to O ₂ and CF ₄ (gas flow rate was 80 cm ³ / min each) using a vacuum plasma device, and one side was 15 minutes × 2 times. The plasma treatment under the conditions described in (1) above so that the contact angle with triallyl isocyanurate is 35 °, the surface energy is 60 mJ / m ² , and the centerline surface roughness Ra is 0.10 μm. The above varnish was applied to the above by a doctor blade method to form a thermosetting polyphenylene ether coating layer having a thickness of about 20 μm. And
Similarly, a polyphenylene ether coating layer was formed on the lower surface of the liquid crystal polymer layer to produce an insulating film.

Further, a through hole having a diameter of 65 μm was formed in this insulating film by a CO ₂ laser, and a conductor paste containing copper powder and an organic binder was embedded in the through hole by screen printing to form a through conductor.

Next, the transfer supporting film having a thickness of 12 μm and having a circuit-shaped copper foil attached thereto and the insulating film having the through conductor formed thereon were aligned with each other, and a pressure of 3 MPa was applied by a vacuum laminating machine at a pressure of 3 MPa. After pressing for 2 seconds, the transfer support film was peeled off and the wiring conductor was embedded on the insulating film. Finally, four insulating films having this wiring conductor formed thereon were stacked, and heat-treated at a temperature of 200 ° C. for 5 hours under a pressure of 3 MPa to completely cure them to obtain a multilayer wiring board.

The test board for evaluating the insulating property was used to form a comb-shaped wiring conductor with a wiring width of 50 μm and a wiring interval of 50 μm in the multilayer wiring board, and to evaluate the conductivity. In the test board, the via chain was formed with the upper and lower two-layer wiring conductors positioned via the insulating layer of the multilayer wiring board and the through conductors electrically connecting the two. Further, as the test board for evaluating the high frequency transmission characteristics, a wiring conductor having a stripline structure was formed inside the multilayer wiring board.

(Comparative Example 1) The multilayer wiring board used for Comparative Example 1 was first formed into a circuit-like wiring by using a photoresist for a liquid crystal polymer layer having a melting point of 320 ° C. and having a copper foil adhered to the surface by heat melting. A conductor is formed, then a through hole having a diameter of 65 μm is formed by a CO ₂ laser, and a conductor paste containing copper powder and an organic binder is embedded in the through hole by screen printing to form a through conductor. After making the boards, these circuit boards have a melting point of 280 ° C.
285 under the pressure of 1 MPa with the liquid crystal polymer layer of
It was manufactured by hot pressing at a temperature of ° C for 5 minutes.

(Comparative Example 2) The multilayer wiring board used for Comparative Example 2 uses a liquid crystal polymer layer having a melting point of 320 ° C., in which a copper foil is adhered to the surface via an epoxy resin adhesive. It was manufactured by the same method as the multilayer wiring board for Comparative Example 1.

The insulation was evaluated by subjecting the sample to a high temperature bias test with an applied voltage of 5.5 V under conditions of a temperature of 130 ° C. and a relative humidity of 85%, and measuring the insulation resistance between wiring conductors after 168 hours. It was evaluated by comparing the amount of change before and after the test.
In addition, the conductivity was evaluated at a temperature of -55 ° C for 30 minutes.
Min., A temperature cycle test was conducted under the condition of 125 ° C. for 30 minutes as one cycle, the conduction resistance of the via chain after 1000 cycles was measured, and evaluation was made by comparing the amount of change in conduction resistance before and after the test. Furthermore, the evaluation of high frequency transmission characteristics is
Using a sample with a strip structure, the frequency is 100M
It was evaluated by measuring high frequency transmission characteristics in the range of Hz to 40 GHz.

Table 1 shows the evaluation result of the insulation property, Table 2 shows the evaluation result of the conduction resistance, and Table 3 shows the evaluation result of the transmission characteristic.

[0063]

[Table 1]

[0064]

[Table 2]

[0065]

[Table 3]

From Table 1, it was found that the multilayer wiring board of Comparative Example 1 had a low insulation resistance after the high temperature bias test of 3.5 × 10 ⁶ Ω and was inferior in heat resistance. Also, from Table 2,
It was found that the multilayer wiring board of Comparative Example 1 suffered disconnection in the temperature cycle test, and was inferior in insulating property and temperature cycle property. Further, from Table 3, the multilayer wiring board of Comparative Example 2 is 20
It was found that the transmission characteristics deteriorated to -1.0 dB or less in the high frequency region of GHz or higher, and the high frequency transmission characteristics were inferior.

On the other hand, the multilayer wiring board of the present invention is
The insulation resistance is as large as 2.7 × 10 ¹¹ Ω even after the high temperature bias test, the rate of change in the conduction resistance is as small as 2% even after the temperature cycle test, and the transmission characteristics are also small at -0.51 dB even in the high frequency range of 40 GHz. It was an excellent thing.

[0068]

According to the insulating film of the present invention, the contact angle with triallyl isocyanurate is 3 to 50 °,
In addition, since the coating layer made of polyphenylene ether organic material is formed on the upper and lower surfaces of the liquid crystal polymer layer having a surface energy of 45 to 70 mJ / m ² , the coating layer spreads well on the upper and lower surfaces of the liquid crystal polymer layer. , The activated molecular layer on the surface of the liquid crystal polymer layer, which is relatively easily moved by heat, and the coating layer are well entangled with each other, and as a result, an insulating film which does not peel off between the two even in the high temperature bias test. be able to. In addition, since the polyphenylene ether-based organic molecule is not as rigid as the liquid crystal polymer molecule, and the molecule is relatively easy to move because it does not exhibit regular orientation, as a result, even when the insulating films are multilayered, Adhesion is good, and there is no possibility that insulation failure occurs due to peeling between films in a high temperature bias test. further,
Even when the wiring conductor is arranged on the surface of the insulating film, the polyphenylene ether-based organic compound molecules can enter the fine recesses on the surface of the wiring conductor to exert a sufficient anchoring effect, and the adhesion between the insulating film and the wiring conductor can be improved. The result is good, and as a result, there is no possibility that the wiring conductor is broken due to peeling between the two under high temperature and high humidity. In addition, since the frequency behavior of the dielectric constant of the coating layer made of polyphenylene ether organic material and the liquid crystal polymer layer are almost the same, even if a slight thickness variation occurs in the coating layer due to pressure when bonding the wiring conductor, It is possible to obtain an insulating film excellent in high-frequency transmission characteristics without causing deterioration in transmission characteristics in a region.

Further, according to the insulating film of the present invention, in the above structure, the center line surface roughness Ra of the upper and lower surfaces of the liquid crystal polymer layer is 0.05 to 5 μm, so that the upper and lower surfaces of the liquid crystal polymer layer are polyphenylene ether type. The coating layer made of an organic substance has a good anchoring effect and good adhesiveness, and an insulating film in which the liquid crystal polymer layer and the coating layer are more firmly adhered can be obtained.

Further, according to the insulating film of the present invention,
In the above configuration, since the polyphenylene ether-based organic material is a thermosetting polyphenylene ether, the thermosetting polyphenylene ether is excellent in heat resistance and dimensional stability, as a result, excellent in temperature cycle reliability, and the wiring conductor It is possible to obtain an insulating film having good positional accuracy when bonding.

Further, according to the multilayer wiring board of the present invention, since the multilayer wiring board is formed by using the above-mentioned insulating film, the multilayer wiring board is excellent in moisture resistance, continuity reliability and high frequency transmission characteristics. You can

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an embodiment of an insulating film of the present invention.

FIG. 2 is a sectional view showing an example of an embodiment of a hybrid integrated circuit in which a semiconductor element is mounted on a multilayer wiring board of the present invention.

FIG. 3 is an enlarged cross-sectional view of a main part of the multilayer wiring board shown in FIG.

[Explanation of symbols]

1 ... Liquid crystal polymer layer 2 ... coating layer 3 ... Insulation film 4 ... Wiring conductor 5 ... Penetration conductor 6 ... Multi-layer wiring board

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 71/12 C08L 71/12 H05K 1/03 610 H05K 1/03 610H 3/38 3/38 EF Term (Reference) 4F100 AA20 AK54B AK54C AK80A BA03 BA06 BA10B BA10C DE01 EJ61 GB43 JB04A JB13B JB13C JG04 JK14A YY00A 4J002 CH071 FD010 FD130 CC32 A32 A21 A22 A22A22A22A21A21A22A22A21A21A22A21A22A21A22A22A21A21A22A21A21A22A22A22A21A21A22A22A22 DD02 DD12 DD32 EE06 EE07 EE09 EE13 EE18 GG28 HH01 HH06 HH08 HH11 HH25 HH26

Claims (4)

[Claims] 1. A contact angle with triallyl isocyanurate is 3 to 50 ° and a surface energy is 45 to 7.
An insulating film comprising a liquid crystal polymer layer of 0 mJ / m ² and a coating layer made of a polyphenylene ether organic material formed on the upper and lower surfaces thereof. 2. The insulating film according to claim 1, wherein the upper and lower surfaces of the liquid crystal polymer layer have a centerline surface roughness Ra of 0.05 to 5 μm. 3. The insulating film according to claim 1, wherein the polyphenylene ether-based organic material is a thermosetting polyphenylene ether. 4. The insulating film according to claim 1, wherein a wiring conductor made of a metal foil is disposed on at least one of the upper and lower surfaces, and the insulating film is laminated. A multilayer wiring board, characterized in that the wiring conductors located above and below with a pinch therebetween are electrically connected via a penetrating conductor formed in the insulating film.