JP4218389B2 - Insulation layer, metal with resin, carrier film with resin, and multilayer printed circuit board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an insulating layer, a metal foil with resin, a carrier film with resin, and a multilayer printed circuit board.
[0002]
[Prior art]
In recent years, portable electronic devices such as notebook personal computers and mobile phones have been required to be lighter and smaller. For this reason, printed circuit boards on which CPUs, LSIs, etc. in electronic devices are mounted are naturally required to be small and light. To achieve small size and light weight, reduce the thickness of the insulating resin layer, reduce the printed wiring width and distance between wiring, reduce the through-hole diameter and reduce the through-hole plating thickness, etc. is required. Here, if the plating thickness is reduced, cracks may occur in the plated metal during thermal shock, and the insulating resin layer is required to have heat resistance and crack resistance.
[0003]
At the same time, speeding up of these information processing devices is also demanded, and the CPU clock frequency is increasing. For this reason, a high signal propagation speed is required, and a printed circuit board having a low dielectric constant and a low dielectric loss tangent is required to realize this.
[0004]
A benzocyclobutene resin is used as a resin having excellent heat resistance and excellent dielectric properties. Since the benzocyclobutene resin does not generate a functional group having a large polarizability such as a hydroxyl group by a curing reaction, the dielectric properties are very excellent (see Patent Document 1).
[0005]
However, benzocyclobutene resin is brittle in mechanical properties due to its skeletal structure, and when benzocyclobutene resin is used for a resin-coated metal foil or the like, there is a problem in crack resistance in cold shock.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-21807
[Problems to be solved by the invention]
An object of the present invention is to provide an insulating layer, a resin-coated metal foil, a resin-coated carrier film, and a multilayer printed circuit board having excellent dielectric properties, crack resistance, and properties after high-temperature treatment.
[0008]
[Means for Solving the Problems]
Such an object is achieved by the present invention described in the following (1) to (11).
(1) An insulating layer of a laminated board, comprising a resin composition containing a benzocyclobutene resin and a compound having an acryl group or a methacryl group at a terminal and a bisphenol F-type structure Insulating layer.
(2) The insulating layer is composed of a first layer containing a benzocyclobutene resin and a second layer containing a benzocyclobutene resin, and has an acrylic group or a methacrylic group at the terminal, The insulating layer according to (1), which is contained in at least one of the compound having the bisphenol F-type structure and the first layer or the second layer.
(3) The insulating layer according to (1) or (2), wherein the benzocyclobutene resin is represented by the formula (I).
[Chemical 3]
(4) The insulating layer according to any one of (1) to (3), wherein the compound having an acrylic group or a methacrylic group at the terminal and having a bisphenol F-type structure is represented by the formula (II) .
[Formula 4]
(5) having said terminal acrylic groups or methacrylic groups, and the number average molecular weight of the compound having a bisphenol F type structure, according to any one to the (1) to a 300 to 100,000 of (4) Insulating layer.
(6) The content of the compound having an acryl group or a methacryl group at the terminal and having a bisphenol F structure is 10 to 80 parts by weight with respect to 100 parts by weight of the benzocyclobutene resin. The insulating layer according to any one of 1) to (5).
(7) The insulating layer according to any one of (1) to (6), wherein the compound having an acryl group or a methacryl group at the terminal and having a bisphenol F-type structure is liquid at room temperature.
(8) A resin-coated metal foil comprising the insulating layer according to any one of (1) to (7) and a metal foil.
(9) A carrier film with a resin comprising the insulating layer according to any one of (1) to (7) and a carrier film.
(10) A multilayer printed circuit board, wherein the resin-coated metal foil according to (8) is superposed on one or both surfaces of the inner layer circuit board and heated and pressed.
(11) A multilayer printed circuit board, wherein the carrier film with resin according to (9) is superposed on one side or both sides of an inner layer circuit board and heated and pressurized.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the insulating layer, the metal foil with resin, the carrier film with resin and the multilayer printed circuit board of the present invention will be described in detail.
The insulating layer of the present invention is an insulating layer of a laminated board, and is characterized by being composed of a resin composition containing a benzocyclobutene resin and a compound having a bisphenol F-type structure.
Moreover, the metal foil with resin of this invention has the above-mentioned insulating layer and metal foil, It is characterized by the above-mentioned.
Moreover, the carrier film with resin of this invention has the above-mentioned insulating layer and a carrier film, It is characterized by the above-mentioned.
The multilayer printed circuit board of the present invention is characterized in that the above-mentioned resin-coated metal foil or the like is superposed on one or both surfaces of the inner layer circuit board and heated and pressurized.
[0010]
First, the insulating layer of the present invention will be described.
The insulating layer of this invention is used for the insulating layer of a laminated board. As a laminated board, circuit board materials, such as a multilayer printed wiring board and a semiconductor mounting board, etc. are mentioned, for example. The insulating layer of the present invention is composed of a benzocyclobutene resin and a compound having a bisphenol F type structure. Thereby, the dielectric properties and crack resistance of the insulating layer can be improved. Furthermore, it is possible to prevent a decrease in dielectric characteristics and a decrease in water absorption after the high temperature treatment.
[0011]
The benzocyclobutene resin is not particularly limited as long as it includes a cyclobutene skeleton. Among these, it is preferable to include a benzocyclobutene resin represented by the formula (I). Thereby, a glass transition temperature can be made high and the resin characteristics (specifically dielectric characteristics, heat resistance, etc.) after hardening can be improved.
[Chemical formula 5]
Since the benzocyclobutene resin does not generate a functional group having a large polarizability such as a hydroxyl group by a curing reaction, the dielectric property is very excellent and the water absorption is low. Moreover, since it has a rigid chemical structure, it has excellent heat resistance.
[0012]
B-staged benzocyclobutene resin is also preferably used for adjusting moldability and is included in the benzocyclobutene resin of the present invention. B-staging is performed by heating and melting. B-staged benzocyclobutene resin refers to those having a number average molecular weight of 500 or more.
[0013]
A B-staged benzocyclobutene resin having the above formula (I) is also preferably used for adjusting moldability and fluidity, and is included in the present invention. The number average molecular weight of the B-staged benzocyclobutene resin having the formula (I) is usually 3,000 to 1,000,000.
The number average molecular weight can be measured using, for example, gel permeation chromatography (GPC).
[0014]
Examples of the compound having the bisphenol F type structure include bisphenol F, bisphenol F dimethyl ether, bisphenol F diethyl ether, bisphenol F glycerolate (1 glycerol / phenol) dimethyl, bisphenol F glycerolate (1 glycerol / phenol) diethyl, and bisphenol F. A derivative such as diethoxylate (1EO / phenol) dimethyl and a functional group such as a hydroxyl group, a cyanate group, an isocyanate group, an epoxy group, an amino group, an acryl group, and a methacryl group at the terminal, and a bisphenol F-type skeleton And the like (for example, bisphenol F diethoxylate (1EO / phenol) diacrylate) and the like.
Among these, a compound having an acryl group or a methacryl group at the terminal and having a bisphenol F structure is preferable. Thereby, the tack on the resin surface of the metal foil with resin and the carrier film with resin can be prevented. Furthermore, compatibility with the benzocyclobutene resin can be improved, and a decrease in dielectric properties and water absorption can be prevented.
[0015]
Moreover, as a compound which has the said bisphenol F-type structure, what is represented by Formula (II) is preferable. As a result, the dielectric properties after the high temperature treatment may deteriorate.
[Chemical 6]
The reason why a compound having a bisphenol F type structure is superior to a compound having a bisphenol A type structure is that the bisphenol A type is a rigid compound because it mainly has a para-oriented structure. This is considered to be a flexible compound because of mixing ortho and para orientations.
[0016]
Furthermore, a compound having a bisphenol F-type structure is excellent in compatibility with a benzocyclobutene resin. When the compatibility between the benzocyclobutene resin and the compound having a structure is excellent, in addition to the effect of improving the crack resistance, the adhesion to the metal can be improved. A compound having a bisphenol F structure has excellent rubber elasticity because it contains a soft segment after curing, and is hardly oxidized even when exposed to high temperature conditions. Furthermore, since it has a chemical structure with few polar groups in the skeleton, the dipole moment is small and the dielectric properties are not deteriorated.
Therefore, by using a compound having a bisphenol F-type structure in combination with the benzocyclobutene resin, it is possible to improve the crack resistance and the adhesion to the metal while maintaining excellent dielectric properties. Furthermore, it is possible to prevent a decrease in dielectric properties and water absorption after the high temperature treatment.
[0017]
The number average molecular weight of the compound having the bisphenol F-type structure is not particularly limited, but is preferably 300 to 100,000, and particularly preferably 350 to 10,000. If the number average molecular weight is less than the lower limit, the dielectric properties and water absorption may be deteriorated. If the number average molecular weight exceeds the upper limit, the compatibility with the benzocyclobutene resin may be reduced.
The number average molecular weight can be measured using, for example, GPC.
[0018]
The content of the compound having the bisphenol F-type structure is not particularly limited, but is preferably 10 to 80 parts by weight, and particularly preferably 15 to 50 parts by weight with respect to 100 parts by weight of the benzocyclobutene resin. If the content is less than the lower limit value, the effect of improving crack resistance may be reduced, and if the content exceeds the upper limit value, tackiness may occur in the resin layer and workability may be reduced.
[0019]
The compound having the bisphenol F-type structure is not particularly limited, but is preferably liquid at room temperature. Thereby, the compatibility with the benzocyclobutene resin can be particularly improved.
The reason why a compound having a liquid bisphenol F-type structure is superior in compatibility with a benzocyclobutene resin compared to a solid resin is that a compound having a liquid bisphenol F-type structure is easily dissolved in a solvent. This is because it becomes easy to uniformly mix the benzocyclobutene resin and the compound having a bisphenol F-type structure.
[0020]
In addition to the benzocyclobutene resin and the compound having a bisphenol F type structure, other resins may be added to the insulating layer of the present invention.
Examples of other resins include polyolefin-based thermoplastic elastomers, polyamide-based elastomers, and polyester-based elastomers.
[0021]
The insulating layer of the present invention is not particularly limited, and is a resin layer having a first layer containing a benzocyclobutene resin and a second layer containing a benzocyclobutene resin, the first layer or the second layer It is preferable to have a resin layer containing a compound having a bisphenol F-type structure in at least one layer. Thereby, in addition to the above-mentioned excellent dielectric properties and crack resistance, the moldability (in particular, the thickness of the resin layer can be made more uniform) can be improved. This is because if the thickness of the resin layer can be made more uniform, the dielectric characteristics can be further improved.
[0022]
The compound having a bisphenol F-type structure may be contained in at least one of the first layer and the second layer, but is preferably contained in both layers. Thereby, crack resistance can be improved more.
[0023]
The first layer is preferably formed on a metal foil or carrier film surface, and the second layer is preferably formed on the first layer.
Different resin components can be used for the first layer and the second layer, but it is preferable to use the same resin component. Thereby, the characteristic of a product can be made more uniform.
[0024]
The reaction rate of the resin constituting the first layer is not particularly limited, but is preferably higher than the reaction rate of the resin constituting the second layer. Thereby, especially moldability, such as metal foil with resin, can be improved. The said reaction rate can be calculated | required with a differential scanning calorimeter (DSC), for example.
[0025]
The thickness of the first layer is not particularly limited, but is preferably 10 to 100 μm, and particularly preferably 20 to 80 μm. When the thickness is within the above range, cracking of the insulating layer can be prevented particularly when the insulating layer is coated on a metal foil or carrier film and wound on a roll after drying.
[0026]
The thickness of the second layer is not particularly limited, but is preferably 10 to 100 μm, and particularly preferably 20 to 80 μm. When the thickness is within the above range, cracking of the insulating layer can be prevented particularly when the insulating layer is coated on a metal foil or carrier film and then wound on a roll.
[0027]
In the insulating layer of the present invention, a curing accelerator, a coupling agent, a flame retardant, a filler, and other components may be added within a range not departing from the object of the present invention.
[0028]
Next, the metal foil with resin and the carrier film with resin of the present invention will be described.
The metal foil with resin and the carrier film with resin of the present invention have the insulating layer on at least one side thereof. The configuration of the resin-coated metal foil of the present invention will be specifically described with reference to the drawings.
In the metal foil 1 with resin of the present invention, two resin layers 12 made of a resin composition containing a benzocyclobutene resin or the like are formed on the upper surface (upper side in FIG. 1) of the metal foil 11 as shown in FIG. The That is, a first layer 121 composed of the resin composition and a second layer 122 composed of the resin composition are formed. Thereby, both dielectric properties and moldability can be achieved.
The same applies to a carrier film with resin.
[0029]
The insulating layer can be formed on the metal foil and the carrier film by various methods, but it is usually preferable from the viewpoint of film forming property to use in the form of a varnish in which a resin or the like forming the insulating layer is dissolved in a solvent. . The solvent used preferably has good solubility in the composition, but a poor solvent may be used as long as it does not adversely affect the composition. Examples of good solvents include toluene, xylene, mesitylene, cyclohexanone, and the like. Moreover, when preparing a varnish, although solid content of a resin composition is not specifically limited, 20 to 90 weight% is preferable and 30 to 70 weight% is especially preferable.
[0030]
Examples of the metal constituting the metal foil include copper or a copper alloy, aluminum or an aluminum alloy, and the resin constituting the carrier film includes a fluorine resin, a polyimide resin, polybutylene terephthalate, and polyethylene terephthalate. And polyester resins.
[0031]
In the present invention, a resin varnish obtained by dissolving the resin or the like constituting the insulating layer in a solvent is applied to a metal foil or a carrier film, and dried at, for example, 80 to 200 ° C. A carrier film with a resin can be obtained. In addition, the first layer and the second layer can be formed by repeating the above operation a plurality of times.
10-100 micrometers is preferable and, as for the thickness of the insulating layer after coating and drying, 20-80 micrometers is especially preferable. Thereby, there is no generation | occurrence | production of a crack of an insulating layer and the powder fall at the time of cutting can also be decreased.
[0032]
Next, a multilayer printed circuit board will be described.
The multilayer printed circuit board of the present invention is a multilayer printed circuit board obtained by superimposing the above-mentioned metal foil with resin or the like on one or both surfaces of the inner layer circuit board and heating and pressing.
When using metal foil with resin, the above-mentioned metal foil with resin is superposed on one or both sides of the inner layer circuit and heated and pressed to obtain a laminate. In the case of a carrier film with resin, peeling or heating after laminating the carrier film with resin, peeling before pressurization,
A multilayer printed wiring board is obtained by overlapping, heating and pressing.
Although the temperature to heat is not specifically limited, 140-240 degreeC is preferable. Although the said pressurization pressure is not specifically limited, 10-40 kg / cm < ² > is preferable.
Further, examples of the inner layer circuit board include a circuit in which circuits are formed on both sides of a copper clad laminate and blackened.
[0033]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited to this.
Example 1
(1) Preparation of resin varnish As the best benzocyclobutene resin, 100 parts by weight of divinylsiloxane-bisbenzocyclobutene (prepolymerized, number average molecular weight 140,000, cycloten XUR manufactured by Dow Chemical Company), A resin varnish was prepared by dissolving 20 parts by weight of bisphenol F diethoxylate (1EO / phenol) diacrylate) as a compound having a bisphenol F-type structure in mesitylene to a non-volatile concentration of 50% by weight.
[0034]
(2) Production of resin-coated metal foil Using a varnish prepared by dissolving 3 parts by weight of 1,2-bis (azidobenzyl) ethylene as a partial crosslinking agent in 100 parts by weight of the resin varnish described above, a copper foil (thickness 0) was prepared. .018 mm, manufactured by Furukawa Circuit Foil Co., Ltd.) with a resin varnish coated at a thickness of 0.07 mm, dried for 10 minutes in a dryer oven at 150 ° C. and 10 minutes in a dryer oven at 170 ° C. The resin layer was formed. Subsequently, a varnish prepared by dissolving 0.5 part by weight of 1,2-bis (azidobenzyl) ethylene in 100 parts by weight of the resin varnish described above was stacked on the first resin layer, and the thickness was 0.07 mm. The second resin layer is formed by coating and drying in a dryer oven at 150 ° C. for 10 minutes and in a dryer oven at 170 ° C. for 10 minutes, and the total resin thickness (first and second layers) And a metal foil with resin having a thickness of 0.07 mm.
[0035]
(3) Manufacture of multilayer printed circuit board The copper foil surface of a double-sided copper-clad laminate with copper foil stretched on both sides is blackened (copper oxide formation) and then reduced, with the above resin on both sides A metal foil was heated and pressure bonded at 170 ° C. for 1 hour, 200 ° C. for 2 hours, and the surface copper foil was etched after thermosetting to produce a multilayer printed circuit board.
[0036]
(Example 2)
The procedure of Example 1 was repeated except that the amount of the compound having a bisphenol F type structure (bisphenol F diethoxylate (1EO / phenol) diacrylate) was changed to 60 parts by weight.
[0037]
(Example 3)
The procedure of Example 1 was repeated except that the amount of the compound having a bisphenol F-type structure (bisphenol F diethoxylate (1EO / phenol) diacrylate) was 12 parts by weight.
[0038]
(Example 4)
Instead of producing the metal foil with resin, the same procedure as in Example 1 was conducted except that a carrier film with resin was produced as follows.
Instead of metal foil, a polyimide film (Kapton EN manufactured by Toray DuPont Co., Ltd., thickness 25 μm) was used as a carrier film.
[0039]
(Example 5)
The production of the metal foil with resin was the same as Example 1 except that the resin layer was coated as a single layer as follows.
Copper foil (thickness 0.018 mm, manufactured by Furukawa Circuit Foil Co., Ltd.) was prepared by dissolving 3 parts by weight of 1,2-bis (azidobenzyl) ethylene as a partial crosslinking agent in the resin varnish described above. The resin varnish was applied at a thickness of 0.14 mm and dried in a dryer oven at 150 ° C. for 10 minutes and in a dryer oven at 170 ° C. for 10 minutes to prepare a metal foil with a resin having a resin thickness of 0.07 mm.
[0040]
(Comparative Example 1)
Example 1 was repeated except that the compound having a bisphenol F-type structure was not added.
[0041]
The following evaluation was performed about the multilayer printed circuit board obtained by each Example and the comparative example. In addition, the method of each evaluation is shown collectively. The obtained results are shown in Table 1.
(1) Dielectric characteristics The dielectric constant and dielectric loss tangent were measured in the A state by the void measurement method.
[0042]
(2) Crack resistance The crack resistance was evaluated by a liquid phase cooling test (treatment at −65 ° C. and 125 ° C. for 30 minutes / 300 cycles). The measurement was carried out using a Tabai Espec liquid bath thermal shock device TSB-2 type, Fluorinert liquid. In addition, the presence or absence of the crack was judged visually. Each symbol indicates the following items.
(Double-circle): A crack does not generate | occur | produce at all.
○: Some cracks occur but there is no practical problem.
(Triangle | delta): A crack generate | occur | produces partially and is impractical.
X: Cracks occur.
[0043]
(3) Characteristics after high-temperature treatment The multilayer printed wiring boards obtained in each Example and Comparative Example were treated in a dryer at 125 ° C for 1000 hours. Thereafter, the dielectric properties were measured as described above. Further, the water absorption after immersion in water for 24 hours was measured.
[0044]
{Circle around (4)} Formability Formability was evaluated based on the presence or absence of voids after the production of the multilayer printed circuit board. The presence or absence of voids was determined visually. Each symbol represents the following items.
A: No void was generated.
○: Some voids are generated, but there is no practical problem.
Δ: Some voids occur and cannot be used practically.
X: Void occurred.
[0045]
(5) Thickness accuracy For thickness accuracy, the cross section of the multilayer printed circuit board was observed with an optical microscope. Each symbol indicates the following items.
A: Thickness variation is less than 15 μm.
○: Some variation in thickness is 15 to 20 μm, but there is no practical problem.
Δ: Some variation in thickness is 20 to 25 μm, and cannot be used practically.
X: Thickness variation exceeds 25 μm.
[0046]
(6) Adhesiveness Adhesiveness was evaluated by copper foil peel strength. The copper foil peel strength was measured according to JISC 6481.
[0047]
(7) Mechanical properties Mechanical properties were measured by measuring the elastic modulus, tensile strength, and elongation rate of the multilayer printed circuit board obtained by removing the copper foil by etching. Elastic modulus, tensile strength, and elongation were measured in a tensile mode at a load full scale of 20 kgf and a speed of 5 mm / min.
[0048]
(8) The tackiness (stickiness) of the resin surface of the metal foil with tackiness resin and the carrier film with resin was evaluated by tactile sensation. Each code is as follows.
◎: No stickiness ○: Some stickiness, but practical level △: Some stickiness, not practical use ×: There is stickiness [0049]
[Table 1]
[0050]
As is apparent from the table, Examples 1 to 5 were excellent in dielectric properties, crack resistance and dielectric properties after high temperature treatment.
In addition, Examples 1 to 4 were particularly excellent in moldability.
In addition, Examples 1 to 4 were particularly excellent in thickness accuracy.
In addition, Examples 1 and 3 to 5 were excellent in workability without tack.
[0051]
【The invention's effect】
According to the present invention, it is possible to provide an insulating layer, a metal foil with resin, a carrier film with resin, and a multilayer printed circuit board that are excellent in dielectric properties, crack resistance, and properties after high-temperature treatment.
In addition, when the insulating layer has a specific layer structure, it is particularly excellent in moldability and thickness accuracy.
[Brief description of the drawings]
FIG. 1 is a side view showing an example of a metal foil with resin in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal foil with resin 11 Metal foil 12 Resin layer 121 1st resin layer 122 2nd resin layer

Claims (11)

An insulating layer of a laminated board, comprising a resin composition comprising a benzocyclobutene resin and a compound having an acryl group or a methacryl group at a terminal and a bisphenol F-type structure Insulation layer. The insulating layer is composed of a first layer containing a benzocyclobutene resin and a second layer containing a benzocyclobutene resin , having an acryl group or a methacryl group at the terminal, and bisphenol F The insulating layer according to claim 1, wherein the compound having a mold structure is included in at least one of the first layer and the second layer. The insulating layer according to claim 1, wherein the benzocyclobutene resin is represented by the formula (I).
4. The insulating layer according to claim 1, wherein the compound having an acryl group or a methacryl group at the terminal and having a bisphenol F-type structure is represented by the formula (II). 5.
Acrylic groups in the terminal or has a methacrylic group, and the number average molecular weight of the compound having a bisphenol F type structure, the insulating layer according to any one of the claims 1 to 300 to 100,000 4. The content of the compound having an acryl group or a methacryl group at the terminal and having a bisphenol F-type structure is 10 to 80 parts by weight with respect to 100 parts by weight of the benzocyclobutene resin. The insulating layer according to any one of the above. The insulating layer according to any one of claims 1 to 6, wherein the compound having a bisphenol F structure and further having an acryl group or a methacryl group is liquid at room temperature.   A resin-coated metal foil comprising the insulating layer according to claim 1 and a metal foil.   A carrier film with a resin comprising the insulating layer according to claim 1 and a carrier film.   A multilayer printed circuit board, wherein the metal foil with resin according to claim 8 is superposed on one or both sides of an inner layer circuit board and heated and pressurized.   A multilayer printed circuit board, wherein the carrier film with resin according to claim 9 is superposed on one or both surfaces of an inner circuit board, and heated and pressurized.