JPH10239839A - Photocross-linkable coating composition for forming positive image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the dielectric composition for forming a positive image, by light, usable as a solder mask and an inner layer in a multilayer printed circuit board and capable of forming a chemically and thermally highly stable positive image after development and to provide a novel manufacturing method of the multilayer printed circuit board and to render the standard copper foil inner layer unnecessary. SOLUTION: The dielectric composition for forming a positive image by light comprising a novolak resin and a naphthoquinonediazido derivative forms the image part soluble in an aqueous alkaline developing solution, and the developed non-image part of the coating composition is hardened by heating and at that time, it is highly chemically and thermally stabilized in the presence of a cross-linkable resin and a compound containing dicyandiamide or thermally instable halogen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a positive-working photoimageable dielectric composition for forming a permanent inner layer of a multilayer printed circuit board, and to a method for forming such a substrate. The present invention also provides a novel multilayer printed circuit board by selectively plating dielectric layers, eliminating the need for standard copper foil inner layers, and eliminating the need for perforations in most cases by photo-resolution of vias. It also relates to various manufacturing methods. The present invention also relates to the use of the photoimageable dielectric composition as a solder mask.

[0002]

BACKGROUND OF THE INVENTION Multilayer printed circuit boards have traditionally included a stack of individual printed circuit boards or inner layers separated by a dielectric. Many inner circuitries are electrically connected by drilled and plated through holes. Multilayer printed circuit boards provide circuitries in a three-dimensional array, and thus advantageously save space compared to individual printed circuit boards that provide at most two layers of circuitries on a double-sided board. It is.

[0003] These printed circuit boards are generally
A grounded power supply plane is provided inside. These internal planes are often solid sheets of copper separated only by clearance holes (the perforations are required to electrically insulate the through-hole pattern on the printed circuit board). . The ground plane and the power supply plane provide the power supply voltage and current and ground connection for the components of the multilayer printed circuit. The second function of the ground plane and the power supply plane is to provide electromagnetic shielding for the multilayer printed circuit board to reduce electromagnetic interference and radio frequency interference. It is common to add a ground plane on the surface layer to the ground plane and the power supply plane.

[0004] Multilayer circuits allow the formation of composite circuits in a minimal volume. They generally comprise a stack of layers having layers of signal lines (conductors) spaced apart from each other by a dielectric layer, the dielectric layer comprising an electrical interconnect between the layers Have plated holes known as vias.

[0005] The current fabrication method for multilayer substrates is an extension of the method used for fabricating double-sided substrates. The method involves fabrication of separate inner layers having circuit patterns disposed on their surfaces. A photosensitive material is coated, imaged, developed, and etched on the copper surface of the copper-clad inner layer material to form a conductor pattern in the copper cladding protected by the photosensitive coating. After etching, the photosensitive coating is stripped from the copper, leaving a circuit pattern on the surface of the support material. Following the formation of the inner layers, they are generally separated from one another by dielectric prepregs (a layer of glass cloth impregnated with incompletely cured material, typically a B-staged epoxy resin). The preparation of the lay-up of the inner layer, the ground plane layer, the power supply plane layer, etc., creates a multilayer stack. The outer layer of the stack includes a fiberglass filled copper-clad epoxy substrate material having a copper cladding that constitutes the outer surface of the stack. The stack uses heat and pressure to completely cure the B-stage resin and laminate to form a unitary structure.

[0006] Interlayer connections or through hole, buried via and blind hole interlayer connections are used to connect circuit layers in a multilayer substrate. Buried vias are plated through holes that connect both sides of the inner layer.
A blind via generally penetrates one side of the stack, enters the stack, and stops therein. Regardless of the formation of the interlayer connections, the holes are generally drilled in place, through their stack, catalyzed by contact with a plating catalyst, and generally metallized with electroless copper overplated with electrolytic copper. To provide electrical contact between layers in the circuit.

[0007] The use, benefits and fabrication techniques for the manufacture of multilayer substrates are described in Coombs' Printed Circuits Handb.
ook, McGraw Hill Book Company, New York, 2nd editi
on, pp. 20-3-23-19, 1979, which is incorporated herein by reference.

[0008] Multilayer substrates are becoming increasingly complex. For example, a substrate for a mainframe computer may have as many as 36 layers of circuitry in a finished stack having a thickness of about 1/4 inch. These substrates are typically about 102 μm (4 mil).
s) Designed with signal lines of width and vias of about 305 μm (12 mils) diameter for interlayer connections between signal line layers. For high density, signal lines should be about 51μ.
Approximately 51-12 vias, with a width of 2 mils or less
It is desirable to reduce the diameter to 7 μm (2-5 mils) or less.

[0009] The photoimageable dielectric coating for printed circuit boards at the forefront of the above technology must be able to be processed in a minimum number of steps. Their dielectric and photographic printing properties, flexibility, and adhesion between coats must also be excellent. Low exposure speed,
High moisture resistance and good adhesion to the metal to be plated are also important properties of such coatings.

Due to the resolution limits, limited aspect ratio, limited processing latitude (exposure, development), and leaching of organics during the plating cycle, which are found during the use of typical negative photoresists, The present invention relates to a positive photosensitive dielectric composition.

[0011] The development of a positive photoresist is generally performed by applying a resist solution to a copper foil laminated on an epoxy resin support, drying and baking the resist to remove the solvent, and to define an image. The resist is exposed to actinic radiation through a photomask that has been patterned, and the exposed portions of the resist are dissolved in an alkaline developer to reveal an image, rinsed, and in some cases, imaged. Post-bake the resist. Next, the resist-free area comprising the exposed copper substrate is subjected to either etching or electroplating. As mentioned above, the method of the present invention eliminates the use of copper foil.

US Pat. No. 4,672,020 (3M) discloses a first patent.
Teach a multi-layer dry film photoresist comprising a positive photoresist composition comprising o-quinonediazide in a phenol formaldehyde resin as a binder in a functional layer of the present invention. The binder becomes more soluble in aqueous alkaline solutions upon exposure to actinic radiation.

[0013]

Here, we have now incorporated a crosslinkable resin, such as an epoxy resin, and a thermosetting catalyst to chemically develop a developed novolak / diazonaphthoquinone composition after development. Can be very stable both thermally and thermally.

Therefore, in a multilayer printed circuit board,
It is an object of the present invention to provide a thermally crosslinkable, positive working photoimageable dielectric composition that can be used as a solder mask and as an inner layer.

It is a related object of the present invention to provide a novel method of manufacturing a multilayer printed circuit board by selective plating of a dielectric layer and to eliminate the need for a standard copper foil inner layer.

It is another related object of the present invention to provide a positive working photoimageable dielectric composition whose developed image is very stable both chemically and thermally.

It is yet another related object of the present invention to provide a multilayer printed circuit board having a permanent inner layer made of a positive-working photoimaged dielectric composition.

It is yet another related object of the present invention to provide a method for photoresoling vias to produce a multilayer printed circuit board.

[0019]

These and other objects of the present invention will become apparent from the following description. This object is achieved by a photoimageable dielectric composition comprising a curing catalyst selected from the group consisting of a novolak resin, a crosslinkable resin, naphthoquinonediazide, and dicyandiamide, and a thermally unstable halogen-containing compound. Is done.

[0020]

DETAILED DESCRIPTION OF THE INVENTION For a better understanding of the present invention,
The following definitions are adopted.

A photoimageable dielectric coating is an organic dielectric coating composition capable of forming an image by forming a relief image upon exposure to activating radiation and development to form an integral part of the multilayer substrate. means. It may be applied as a liquid coating composition and dried to a semi-cured dry coating, or it may be applied as a dry film. Preferably, the dielectric constant of the coating does not exceed 4.5.

The imaged opening is:
It means a relief image of (1) depressions or grooves defining the pattern of conductors, or (2) openings for interlayer connections in the dielectric coating. The imaged aperture is then selectively metallized, so that the metal is placed in the recess of the relief image.

The term "substantially" means mainly,
It means not completely, and the differences are specified as insignificant.

A major component of the binder for the photoimageable dielectric composition of the present invention is a novolak resin, which imparts aqueous base solubility to the compositions, serves as a backbone for them, and serves as a backbone for the thermal crosslinking of the inner layer. Reacts with the crosslinkable resin in the meantime. Novolak resin is a commonly known phenol,
Products of acid-catalyzed condensation with aldehydes such as formaldehyde, acetaldehyde, and furfural. The term phenol is used herein to refer to phenols and includes alkyl phenols such as cresol, xylenol, and butylated phenol novolak. Suitably, the amount of the novolak resin may be from about 30 to about 80% by weight of the total composition, but from about 45 to 70% of the novolak resin in the photoimageable dielectric coating composition of the present invention. It is preferred to use A preferred photoimageable dielectric coating composition comprises about 46% by weight cresol novolak resin. The resin is widely available from many chemical suppliers.

In order to cure the novolak resin in the photoimageable dielectric composition to produce the inner layer of the multilayer printed circuit board of the present invention, the amount of crosslinkable resin must be from about 5 to about 5 parts of the total composition. It may be about 40% by weight, but is preferably about 10 to about 30, more preferably about 15 to about 25%. Epoxy resins are generally suitable as such crosslinking agents for the purposes of the present invention. A specific example of the epoxy resin is epoxy novolak. Preferred amounts of such multifunctional novolaks are from about 5 to about 20% by weight,
More preferably from about 8 to about 12% by weight, even more preferably about 10% by weight.

The photoimageable dielectric composition of the present invention can be obtained from Elf Atochem using Poly BD605 (POL
Y BD 605) at 25 ° C
It may contain about 20% by weight of an epoxidized polybutadiene having a viscosity of 25000 mPa · s (25000 cps) and an epoxy equivalent of 260.

In the preferred photoimageable dielectric coating composition of the present invention, a butylated phenol novolak is used together with an epoxidized phenol novolak resin. The butylated phenol novolak imparts flexibility to the cured photoimageable dielectric coating of the present invention and imparts a printed image with the photoactive diazonaphthoquinone compound. It comprises about 5 to about 30%, preferably about 5 to about 20% of the total weight of the coating composition of the present invention.
%, More preferably from about 8 to about 12%, even more preferably about 10%.

The naphthoquinonediazide is a photoactive compound that imparts a positive image to the photoimageable dielectric coating of the present invention. Examples of naphthoquinonediazides are naphthoquinone-1,2-diazide-5-sulfochloride,
Includes sulfochloride isomers and diazoquinonesulfonyl esters of trihydroxybenzophenone without limitation. 2,1,5-diazoquinonesulfonyl ester of trihydroxybenzophenone (hereinafter referred to as 215DNQTHB)
The isomer mixture of the isomer mixture of
Available from Chemdesign Corporation of Fitchburg. Upon irradiation with ultraviolet light, such photoactive compounds render the dielectric coating composition soluble in an aqueous alkaline solution. Preferably, about 5% to about 30% of diazonaphthoquinone may be used, but in the formulation of the photoimageable dielectric coating composition of the present invention, about 10% of its total weight.
It is preferred to use from about 20% by weight. Preferred compositions contain about 10% of the diazonaphthoquinone compound.

In the present invention, when a thermally unstable halogen-containing curing catalyst is heated in the photoimageable dielectric coating composition, a strong Lewis acid is formed, thereby causing the crosslinkage therein. Catalyzes the condensation of the novolak resin with the hydrophilic resin, thus effecting curing of the imaged inner layer without the need for an ultraviolet curing step. The thermally labile halogen-containing curing catalyst is diaryliodonium hexafluoroantimonate (or DA
I HFA), tribromomethylphenylsulfone, trichloroacetamide, bis-chloroimidazole, 2,4-
(Trichloromethyl) -4-methoxyphenyl-6-triazine, 2,4- (trichloromethyl) -4-methoxynaphthyl-6-
Illustrated by triazines and 2,4- (trichloromethyl) -piperonyl-6-triazines, all of which are commercially available. Diaryliodonium hexafluoroantimonate is available from Sartomer Company (Sar
tomer Company, Inc.) as a cationic photoinitiator sold under the trademark SarCat. The product Cercat CD-1012 is 2
It is characterized by a hydroxymyristyloxy group attached to one of the two phenyl groups. We have found that lower levels of thermosetting catalyst, such as about 0.1 to about 2% by weight, dissolve the coating to produce a positive working image, except that higher levels produce a negative working image. It has been found that it is effective to cure the coating without substantial hindrance. The amount of such acid generating catalyst is preferably from about 0.5 to about the total weight of the photoimageable dielectric coating composition of the present invention.
1.5% by weight, more preferably from about 1 to about 1.5% by weight
It is.

Dicyandiamide is also useful as a curing catalyst in the photoimageable dielectric coating compositions of the present invention. Preferred is about 0.1 to about 2% by weight of the total weight of the composition.

Melamine and its oligomers and melamine-formaldehyde resin and benzoguanamine-
Polymers thereof, such as formaldehyde resins, urea-formaldehyde resins, and glycoluril-formaldehyde resins and combinations of the foregoing resins are also suitable as crosslinkers for the purposes of the present invention. The melamine, benzoguanamine, and glycoluril resins are available under the trademark CYMEL, and the urea resins are available under the trademark BEETLE. About 5% to about 30% by weight of the total solids in the composition
Is preferred.

To control the flowability of the resin therein while the composition is being cured at elevated temperatures, fillers may be used in amounts of about 2 to about 40% by weight of the total composition. Good.
CAB-O-SIL and SYLOI
Fumed silica, such as that sold under the trademark D), is an example of a useful filler. The above cab-O-
Sil M-5 silica is particularly useful. As a flow control aid and to improve the resistance of the dielectric to permanganate during the swelling and etching process, Degussa's aluminum oxide C (Alminium Ox
Aluminum oxide exemplified by ide C) may be used at a level of about 30% by weight. Hoffma
The mixture of quartz and kaolinite sold under the trademark SILLITIN by n) is useful in the present invention to improve the adhesion of the dielectric to copper.
Silanes and titanates can be used in the coupling of the filler with the polymer matrix to have a beneficial effect on the rheology of the dielectric composition.

Also useful are leveling agents such as those sold under the trademark MODAFLOW in amounts of about 0.2 to about 3% by weight of the composition of the present invention. In the manufacture of the dry film of the present invention, poly (vinyl methyl ether) sold under the trademark LUTANOL M
Softeners such as are particularly useful. Effective amounts of the emollient are from about 10 to about 20% by weight of the total composition.

The dielectric constant of the photoimageable dielectric coating composition of the present invention preferably does not exceed 4.5, more preferably does not exceed 3.5. Its resolution is preferably about 2
54 μm (10 mils) or less, more preferably about 1
It is sufficient to provide a line width of 27 μm (5 mils) or less, and even more preferably about 51 μm (2 mils) or less.

The photoimageable dielectric coating composition of the present invention may be applied to a substrate as a liquid, then dried, imaged by exposure to ultraviolet light, developed and cured, or stored. Then, it may be later laminated on a substrate, formed into an image, and cast as a dry film for curing. The liquid coating composition can be coated on the substrate surface in a variety of ways, including screening, roller coating, curtain coating, and spray coating. A water-miscible solvent, such as propylene glycol methyl ether acetate,
The amount required to adjust the viscosity of the photoimageable dielectric coating composition of the present invention can be used to suit the desired coating method and thickness. The dielectric substrate for a printed circuit board application may be, for example, a glass-epoxy structure or a polyimide. The coating is semi-cured and dried at about 90 ° C. for about 30 minutes and then irradiated with ultraviolet light having a wavelength in the range of 350-450 nm through a mask of the image pattern. All UV dose is 100~ 800 mJ / cm ^2. The exposed coating is then added to 170-300 mol / m ³
(0.17-0.3 normal) in aqueous sodium hydroxide solution
Develop at 80-100 ° F (27-100 ° C), rinse and cure at a temperature of 140-175 ° C for about 1 hour.

Although the above-mentioned developer is a strongly basic solution, it may contain sodium carbonate like the above-mentioned hydroxide. Sodium metasilicate and trisodium phosphate are also suitable for use in the developer. Surfactants are useful in the developer to help image-wise remove the desired portions of the photoimageable dielectric. The surfactant may be anionic, cationic, nonionic, or amphoteric.

The dry film is spread using a Baker bar in a setting of about 4 to about 20 and spreading the liquid coating composition in a convection oven or tunnel dryer for about 2 to about 60 minutes. And dried at about 35 to about 105 ° C. to a thickness of about 13 to about 76 μm (about 0.5 mils to about 3 mi).
ls). Next, at room temperature or elevated temperature, for example,
At 80 ° F., the dry film may be laminated on a dielectric substrate such as a polyimide film or a glass fiber board impregnated with an epoxy resin.
Speed of about 30 to about 150 cm / min (1 to 5 feet per minute);
Roll pressure of 28 to 0.41 MPa (40 to 60 psi), and 113 to 1
At a roll temperature of 50 ° C (225-300 ° F), Hot Roll (DYNACHEM 300 or 3)
60 type) Laminator can be used. Vacuum laminators such as the 724 and 730 types sold by Morton International, Inc. can also be used. Conventional decompression lamination uses mechanical pressure in addition to heat and decompression to compress the dry film. In what is known as the "slap down" method, a rubber blanket is used to press the dry film onto the substrate. During vacuum lamination, the photoimageable dielectric dry film has a cycle time of 30-90 seconds and a
The substrate is heated to a substrate surface temperature of 55-90 ° C. with a slap-down cycle of 1212 seconds. After lamination bake about 90 ℃
(About 194 ° F.) for about 30 minutes, but may be omitted under certain conditions. The laminate is then irradiated with ultraviolet light through an image pattern mask and developed as described above.

A high resolution relief image containing an aperture approximately equal to the thickness of the coating can be achieved as described above. Through the use of such a coating, the imaged aperture for interlayer connections and conductors can be as large as the resolution capability of its dielectric coating and imaging method, and of any desired shape Can be.

The adhesion of the metal to the dielectric coating can be increased by a permanganate treatment including a conditioning step (also known as solvent swelling), an etching step, and a neutralization step. The conditioner may be a mixture of diethylene glycol butyl ether, phosphoric acid, a surfactant, and water. A suitable conditioner is Copper Mars M3
(COPPERMERSE M3) and circuposit MLB211
It is available under the trademark (CIRCUPOSIT MLB 211). Suitable potassium permanganate etching solutions are COPPERMERSE M4 and Circumposit M
It is available under the trademark LB213 (CIRCUPOSIT MLB 213). A preferred neutralizing agent is Copper Mars M6 (COPPERM
ERSE M6) and Circuposit MLB216 (CIRCUPO
It is available under the trademark SIT MLB 216). The above COPPERMERSE products are available from LeaRonal,
Inc.). The above circuposit (C
(IRCUPOSIT) products are sold by Shipley Co.

Selective metal deposition at the imaged openings can be accomplished in a conventional manner. It is characterized by the selective metallization of the relief image of the dielectric coating without increasing the surface resistivity of the underlying substrate between the conductors. Plating may be applied only on those areas where the resist has been removed (additional fabrication of the circuit), or on the entire surface including the area where the resist has been removed by development and also on the resist itself, Alternatively, the process may be performed to a degree intermediate between these two extremes. See U.S. Pat. No. 4,847,114 (Brach et al.) For a discussion of the details of circuitry and interlayer connection fabrication.

In order to increase the adhesive strength, after the electroless metal deposition and the subsequent build-up metallization,
Baking at ~ 160 ° C for 30-60 minutes is preferred.

If the additive method is selected, then the defined circuitry and interlayer connections are made in the areas where the photoimageable dielectric coating has been developed and on the surface of the dielectric. Plating is performed by the specified method. Thus, the plating itself will define the circuitry and other desired graphical features. In the additive method, permanent dielectric photoimaging creates and defines the desired circuitry and other surface topographical features, along with holes and vias that interconnect the various layers of the circuitry. There will be.

If the substrate to be coated is a circuit, the method can include forming a dielectric coating on the circuit having an imaged opening defining the interlayer connection. Metal adheres during plating,
The walls of the imaged aperture in the dielectric coating include metal to ensure the cross-sectional shape of the deposit. The method is continuously repeated to form continuous layers of circuits and interlayer connections.

In the subtractive method, the entire surface will be plated. The circuitry and other graphical features will be defined by subsequent etching of the plated metal. In the subtractive method, to create holes and vias that connect the various layers of the circuitry package,
Generally, the permanent resist will be photo-resolved, thus eliminating the need for hole drilling.

The plating solution is generally an electroless copper plating solution well known in the art, and generally comprises a cupric ion source, a complexing agent for keeping the ions in solution, the cupric ion A reducing agent for reducing to a metallic copper in the presence of a catalyst (for example, formaldehyde), and a pH adjusting agent. Typical copper plating solutions are disclosed in U.S. Patent Nos. 4,834,796, 4,814,009, 4,684,440, and 4,548,644.

The coating compositions and methods of the present invention are further described in the following examples, which are by no means limiting. All parts are by weight unless otherwise indicated, and all components are 100% solids unless otherwise indicated.

[0047]

【Example】

 Example 1 The following composition was prepared.

Constituents% by weight of solids Cresol novolak (Schenectady Resin HRJ10805) 50.1 Epoxy novolak (EPON 164) 4.9 Epoxidized polybutadiene (poly BD605) 19.8 Butylated novolak (Suntrink) 560 (SANTLINK 560)) 14.3 Diazonaphthoquinone sulfonate of 2,1,5-trihydroxybenzophenone 9.9 DAI HFA (CD-1012) 1.0 ───── 100.0 Filler Weight% of the total solids Silica (Syloid 7000) 5.0 Solvent Weight% of total composition Propylene glycol methyl ether acetate 46-48

The above coating composition was thoroughly mixed and applied to the glass / epoxy laminate with a wire draw down bar to a dry thickness of about 25 to about 51 μm (1-2 mils). The coating was then applied at 90 ° C (194
At 30 ° F., dried for 30 minutes and image-wise exposed to actinic radiation from a patterned broadband mercury lamp (ORCH10W201B). Total radiation dose was about 400mJ / cm ^2. The exposed surface is then immersed in a 200 mol / m ³ (0.2 N) aqueous sodium hydroxide solution at 35 ° C. (95 ° F.) for about 2 minutes, thereby selectively exposing the exposed portions of the coating. Removed. The developed coating was cured at 155 ° C. (311 ° F.) for 1 hour. The coating was subjected to three consecutive 5 minute soaks of a conventional permanganate treatment.

Example 2 A photoimageable dielectric coating composition of the present invention was prepared according to the following recipe.

Constituents Weight% of solids Cresol novolak resin 46.0 Epoxidized polybutadiene 20.0 Epoxidized novolak resin 10.0 Butylated novolak resin 10.0 Diazonaphthoquinone 10.0 Diaryliodonium hexafluoroantimonate 1.0 Leveling material 0.2 Filler, colorant, additive 2.8

The same solution as in Example 1 was coated on each of the six epoxy / glass laminates and then dried,
Irradiation, development, and curing as in the examples yielded six inner layers suitable for electroless plating and assembly by compression into multilayer printed circuit boards of the present invention.

Example 3 The following composition was prepared.

Constituents Weight% of solids Cresol novolac (Shenectady Resin HRJ10805) 60.0 Epoxy novolak (Epon 164) 10.0 Butylated novolak (Santlink 560) 15.0 Diazonaphthoquinone sulfonate of 2,1,5-trihydroxybenzophenone 12.5 DAI HFA (CD-1012) 1.0 Leveling material 1.5 ───── 100.0 Filler Weight% based on all solids above Silica (Cab-O-Sil M5) 8.0 Solvent Weight% based on total composition Propylene glycol methyl ether acetate 47.4

The above coating composition was thoroughly mixed and applied to the glass / epoxy laminate with a wire draw down bar to a dry thickness of about 25 to about 51 μm (1-2 mils). The coating is then placed at 100 ° C (1
At 94 ° F.), dried for 30 minutes and imagewise exposed to actinic radiation from a patterned broadband mercury lamp (ORCH10W201B). Total radiation dose was about 400mJ / cm ^2. The exposed surface is then immersed in a 250 mol / m ³ (0.25N) aqueous sodium hydroxide solution at 30 ° C. (86 ° F.) for about 2 minutes, thereby selectively exposing the exposed portions of the coating. Removed. The developed coating was cured at 155 ° C. (311 ° F.) for 1 hour. The coating was subjected to three consecutive 5 minute soaks of a conventional permanganate treatment. This composition gave better resolution and better sidewall profile than that of Example 1.

Claims (18)

[Claims] 1. A positive-working photoimageable dielectric coating composition comprising a novolak resin, a crosslinkable resin, a naphthoquinonediazide, and a curing catalyst selected from the group consisting of dicyandiamide and thermally unstable halogen-containing compounds. Wherein said thermally labile halogen-containing compound is diaryliodonium hexafluoroantimonate, tribromomethyl-phenylsulfone, trichloroacetamide, bis-chloroimidazole,
2,4- (trichloromethyl) -4-methoxyphenyl-6-triazine, 2,4- (trichloromethyl) -4-methoxynaphthyl
-6-triazine, 2,4- (trichloromethyl) -piperonyl
A dielectric coating composition selected from the group consisting of -6-triazine and mixtures thereof. 2. The composition according to claim 1, wherein the novolak resin comprises about 30 to about 30% of the total composition.
The dielectric coating composition according to claim 1, which is 80% by weight. 3. The photoimageable dielectric composition of claim 2, wherein said naphthoquinonediazide is about 5% to about 30% by weight of the total composition. 4. The photoimageable dielectric of claim 2 wherein said curing catalyst is diaryliodonium hexafluoroantimonate and the amount of curing catalyst is from about 0.1 to about 2% by weight of the total composition. Composition. 5. The crosslinkable resin is an epoxy resin, wherein the amount of the crosslinkable resin is from about 5 to about 40% by weight of the total composition.
The photoimageable dielectric composition according to claim 4, which is: 6. The photoimageable dielectric composition according to claim 1, comprising about 45 to about 70% by weight of a cresol novolak resin. 7. About 46% by weight of cresol novolak resin, about 20% by weight of epoxidized polybutadiene, about 10% by weight of naphthoquinonediazide, about 1% by weight of diaryliodonium hexafluoroantimonate, about 8 to about 12%.
The photoimageable dielectric composition of claim 1, comprising about 10% by weight of the epoxidized novolak, and about 8% to about 12% by weight of the butylated phenol novolak. 8. A positively photoimaged dielectric inner layer for a multilayer printed circuit board, said inner layer comprising a novolak resin, a crosslinkable resin, a radiation-induced decomposition product of naphthoquinonediazide, and An inner layer containing a cured mixture of pyrolysis products of a halogen-containing curing catalyst that is unstable to a nucleus. 9. The inner layer according to claim 8, wherein said novolak resin is from about 30 to about 80% by weight of the cured mixture. 10. The inner layer according to claim 9, wherein the crosslinkable resin is an epoxy resin, the amount of which is about 5 to about 40% by weight of the cured mixture. 11. The method according to claim 11, wherein the crosslinkable resin comprises about 15 to about 25% by weight.
An inner layer according to claim 10, wherein the inner layer is an epoxidized polybutadiene. 12. The composition, when cured, comprises about 46% by weight.
Cresol novolak resin, about 20% by weight epoxidized polybutadiene, about 8 to about 12% by weight epoxidized novolak, about 8 to about 12% by weight butylated phenol novolak, and about 0.5 to about 1.5% by weight diaryliodonium 12. The composition of claim 11, comprising hexafluoroantimonate.
The inner layer according to the above. 13. A multilayer printed circuit board comprising a plurality of positive-type photo-imaged dielectric inner layers, wherein the inner layer is made of a novolak resin, an epoxy resin as a crosslinkable resin, or a radiation-induced layer of naphthoquinone diazide. Decomposition products,
And about 0.1 to about 2% by weight of a cured mixture of the thermal decomposition products of dicyandiamide or a thermally labile halogen-containing curing catalyst, wherein each of the photoimaged inner layers comprises lines, holes and A multilayer printed circuit board defining vias, wherein said lines, holes and vias are plated with a conductive metal. 14. The method according to claim 14, wherein the inner layer is a novolak resin, an epoxy resin, a radiation-induced decomposition product of naphthoquinonediazide, and diaryliodonium hexafluoroantimonate, tribromomethyl-phenylsulfone, trichloroacetamide, bis-chloroimidazole,
2,4- (trichloromethyl) -4-methoxyphenyl-6-triazine, 2,4- (trichloromethyl) -4-methoxynaphthyl
-6-triazine, 2,4- (trichloromethyl) -piperonyl
14. The multilayer printed circuit board according to claim 13, comprising a cured mixture of a pyrolysis product of a halogen-containing curing catalyst selected from the group consisting of -6-triazine, and mixtures thereof. 15. The multilayer printed circuit board according to claim 14, wherein the novolak resin is about 30 to about 80% by weight of the mixture before curing. 16. The multilayer printed circuit board of claim 13, wherein said epoxy resin is about 5% to about 40% by weight of the mixture before curing. 17. The multilayer printed circuit board according to claim 13, wherein the mixture before curing comprises about 45 to about 70% by weight of a novolak resin. 18. The halogen-containing curing catalyst is diaryliodonium hexafluoroantimonate,
The multilayer printed circuit board according to claim 14.