KR20010006494A - Positive working photodefinable resin coated metal for mass production of microvias in multilayer printed wiring boards - Google Patents

Abstract

High density laminated multilayer printed circuit boards are fabricated by forming microvias with photoimageable insulating materials. An embossed photosensitive insulating composition 4 on the conductive foil 2 is laminated to the conductive wiring 6 on the substrate 8. After the foil 2 is imaged and the photosensitive insulating composition 4 is imaged and cured, vias 14 are formed in the conductive wiring 6. Next, the conductive wiring 6 is connected 16 to the conductive foil 2 through the via 14, and the next conductive foil 2 is patterned.

Description

Embossed wide-definable resin-coated metals for mass production of microvias in multilayer printed wiring boards {POSITIVE WORKING PHOTODEFINABLE RESIN COATED METAL FOR MASS PRODUCTION OF MICROVIAS IN MULTILAYER PRINTED WIRING BOARDS}

As the demand for high speed, small size and low cost integrated circuit products grows, wiring possibilities have reached the limits of the available technology and chips must also be mounted using a flip chip approach. This resulted in a direct chip attachment package. The need to fan out a large number of I / Os on the back of the chip has increased the need to use printed circuit board area. Plated-through-holes use excess space and block routing channels. This leads to the need for high density packages with a large number of interconnections on the outer surface of the printed circuit board and the use of blind microvias.

Rubber coated copper (RCC) has been used in the past to manufacture high density fabricated multilayer printed circuit boards. Currently, microvias of such printed circuit boards manufactured by RCC are manufactured by two methods, including plasma etching and laser drilling. As such, only substrates with access to plasma etching or laser drilling equipment can provide this advanced, blind via printed circuit board. Expensive plasma and laser equipment has prevented the widespread use of RCC technology. In addition, technical shortcomings related to plasma etching and laser technology, such as undercutting by anisotropic etching of plasma and low yields by continuous drilling with lasers, also lead to the large scale commercial use of RCCs in high density multilayer printed circuit boards. Restrict.

Photovia processes have been developed that use photoimageable insulating materials to fabricate multilayer printed circuit boards. In this process, the photoinsulating material is coated onto a patterned core and photoimaged to form via holes. Next, the via holes along the insulating layer surface are plated with copper. US Pat. No. 5,354,593 discloses two optically insulating materials are successively stacked on a conductive core to form via holes, which are then imaged and copper plated in the via holes. U. S. Patent No. 5,451, 721 discloses manufacturing a multilayer printed circuit board by attaching a photosensitive resin layer onto a core having metal wiring on a printed circuit board surface. After forming the image to form the via holes, the resin layer is deposited into the copper layer by an electroless plating technique. U. S. Patent No. 5,334, 487 discloses manufacturing a patterned layer on a printed circuit board by attaching and exposing different photosensitive compositions on opposite sides of a copper foil. One side is shaped and the copper layer is etched, then the remaining layers are developed and metal processing is performed through the holes.

The photovia technology makes it possible to fabricate high density interconnect printed circuit boards using conventional devices, but these techniques have similar drawbacks such as complex copper printing processes or difficulty in adhesion between copper and resin. These problems lower the reliability of the printed circuit board. These problems can be solved by the present invention in which the photosensitive insulating composition on the conductive foil is laminated to the conductive wiring on the substrate. After imaging the foil and imaging and curing the photosensitive insulating composition, vias are formed in the conductive wiring. Next, conductive wiring is connected to the conductive foil through the via, and the next conductive foil is patterned.

The present invention relates to the manufacture of a printed circuit board. More particularly, the present invention relates to the manufacture of high density laminated multilayer printed circuit boards by forming microvias with photoimageable insulating materials.

1 is a schematic view of a photosensitive element according to the present invention laminated to a substrate having metal wiring.

FIG. 2 is a view showing a state before the lamination of the photosensitive element positioned on the substrate and after the photoresist is attached to the opposing surface of the photosensitive element.

Figure 3 shows the structure of Figure 2 after the photoresist is removed and the foil is imaged.

4 illustrates the structure of FIG. 3 after an insulating composition has been imaged.

Figure 5 shows the structure of Figure 4 after removing the non-imaging area of the insulating composition to form the vias.

Figure 6 shows the structure of Figure 5 after plating the vias and providing electrical connections between the conductive wiring and the conductive foil.

Fig. 7 shows another embodiment of the present invention in which the photosensitive element according to the present invention is laminated on a printed board having metal wiring and the conductive foil is removed as a whole.

FIG. 8 shows the structure of FIG. 7 after imaging the insulating composition. FIG.

Figure 9 shows the structure of Figure 8 after removing the non-imaging area of the insulating composition to form a via.

FIG. 10 shows the structure of FIG. 9 after plating the vias and the top surface of the insulating composition to provide a conductive top surface.

The present invention,

(a) attaching a photosensitive element having an embossed photosensitive insulating composition on the surface of the conductive foil to a pattern of conductive wiring on the surface of the substrate such that the photosensitive insulating composition is positioned on the conductive wiring;

(b) attaching a photoresist layer on opposite surfaces of the foil;

(c) exposing the photoresist to actinic radiation to form an image and developing the photoresist so that the removed image portion is at least partially positioned over the conductive wiring so that the removed image portion of the photoresist is Forming an unremoved image portion;

(d) removing the portion of the conductive foil underlying the removed image forming portion of the photoresist without removing the underlying photosensitive insulating composition;

(e) exposing the photosensitive insulating composition portion as a whole to actinic radiation through the removed portion of the conductive foil, selectively heating the photosensitive insulating composition to reduce developer solubility of the unexposed portion of the photosensitive insulating composition, Developing the photosensitive insulating composition thereby removing only a portion of the photosensitive insulating composition underlying the removed portion of the conductive foil, thereby forming a via in the conductive wiring;

(f) curing the unremoved portion of the photosensitive insulating composition;

(g) electrically connecting the conductive wires to the conductive foil portion through the vias; And

(h) patterning the conductive foil to form a conductive foil wiring pattern.

The present invention also attaches an embossed photosensitive insulating composition layer onto the conductive foil to thereby form a photosensitive element, and subsequently forms a conductive wiring pattern on the surface of the substrate via the photosensitive insulating composition such that the next photosensitive insulating composition is positioned on the conductive wiring. It provides a printed circuit board manufacturing process comprising the step of attaching.

The present invention also provides

(a) attaching a photosensitive element having an embossed photosensitive insulating composition on the surface of the conductive foil to a pattern of conductive wiring on the surface of the substrate such that the photosensitive insulating composition is positioned on the conductive wiring;

(b) removing the conductive foil;

(c) exposing the photoresist to actinic radiation to form an image, selectively heating the photosensitive insulation composition to reduce developer solubility of the unexposed portion of the photosensitive insulation composition, and developing the photoresist to thereby Forming a removed image portion and a non-removed image portion of the photoresist such that the image portion removed by the at least part is located above the conductive wiring;

(d) curing the non-removed portion of the photosensitive insulating composition;

(e) simultaneously forming an electrically conductive layer on the non-removed portion of the photosensitive insulating composition and electrically connecting the conductive wiring to the conductive foil portion through the via; And

(f) patterning the electrically conductive layer to form a conductive wiring pattern.

The present invention also attaches an embossed photosensitive insulating composition layer onto the conductive foil to thereby form a photosensitive element, and subsequently forms a conductive wiring pattern on the surface of the substrate via the photosensitive insulating composition such that the next photosensitive insulating composition is positioned on the conductive wiring. It provides a printed circuit board manufacturing process comprising the step of attaching.

By the process of the present invention, microvias are made using embossed photosensitive resin coated with a metal such as copper. The apparatus and process of the present invention enable substantial cost reduction in printed circuit board manufacturing processes as compared to plasma or laser drilling techniques. Optical microvia technology can also avoid technical limitations associated with plasma and laser drilling methods such as undercutting by anisotropic etching of plasma and low yields by continuous drilling with lasers. Compared with current light via technology, the present invention provides easy copper plating and good adhesion between copper and resin.

The process embodiment of the present invention can be practiced by employing a photosensitive element comprising an embossed photosensitive insulating composition attached to the surface of the conductive foil. Embossed photosensitive insulating compositions are useful materials for use as permanent insulating materials in electronic circuits.

Suitable conductive foils include copper, copper alloys, aluminum, aluminum alloys, and the like, of which double copper foils are most suitable.

Suitable embossed photosensitive insulating compositions may include embossed photoimageable compositions, which include photoacid generators, organic acid anhydride monomers or polymers that can generate acids when exposed to actinic radiation, at least one epoxy, nitrogen containing curing It is formed by mixing a catalyst and optionally a monomer or polymer containing phenol.

The light asset generator used here generates acid when exposed to actinic radiation such as ultraviolet radiation. Photoacid generators are known in the field of photoimaging and may include onium compounds such as aryl derivatives of sulfonium, iodonium and diazonium salts and organic compounds with photoactive halogen atoms.

Preferred photoacid generators include triarylsulfonium and diaryludonium salts with hexafloorphosphate, hexafloorantimonate, hexafluor argenate and tetrafluoroborate anions. Examples of suitable iodonium salts are diphenyl iodonium, dinaphthyl iodonium, di (4-chloronetyl) iodonium, toryl (dotesylbenyl) iodonium, naphthylphenyl iodonium, 4- (tri-fluoromethylphenyl ) Salts such as phenyl iodonium, 4-ethylphenyl-phenyl iodonium and di (4-phenylphenyl) iodonium. Di-phenyl iodonium salts are preferred. Examples of suitable sulfonium salts include triphenylsulfonium, dimethylphenylsulfonium, tritorylsulfonium, di (mesosinaphthyl) methylsulfonium, dimesylnaphthylsulfonium, tritorylsulfonium, di (methosylnaphthyl) Salts of methylsulfonium, dimethylnaphthylsulfonium, 4-butosylphenyldiphenylsultonium, and 4-hydroxycytophenyldiphenylsulfonium. Tri-phenylsulfonium is preferred. Organic compounds having photoactive halogen atoms include alpha-halo-pi-nitrotollun, alpha-halomethyl-s-triazine, carbon tetrabromite and the like. These acid generators may be used alone or as two or more compositions.

The light asset generator component is preferably about 0.05 to 20% by weight, preferably 0.2 to 10% by weight and most preferably 0.5 to 5% by weight of the non-payment portion of the composition.

The composition comprises an organic acid anhydride monomer or polymer. Suitable acid anhydrides are anhydride functional polymers having a number average molecular weight of about 500 to 50,000, preferably about 1,000 to 10,000. Examples of suitable anhydrides include styrene-maleic anhydride, styrene-alkyl methacrylate-itaconic anhydride, methylmethacrylate-butyl acrylate-itaconic anhydride, butyl acrylate-styrene-maleic anhydride and the like. Preferred are styrene-maleic anhydride polymers, wherein the styrene to maleic anhydride molecular ratio is about 1: 1 to 3: 1. Also dodecynyl succinic anhydride, trimellitic anhydride, chloroenoic anhydride, phthalic anhydride, methyl hexahydroxytal anhydride, 1-methyl tetrahydrotyl anhydride, hexahydrotalic anhydride, methyl ned anhydride, methyl Butenyltetrahydrophthalic anhydride, benzophenol terracarboxylic dianhydride and methylcyclohexynedicarboxylic acid anhydride are suitable. These acid anhydrides are used alone or as a composition.

These anhydride components are preferably about 10 to 90 weight percent, preferably about 20 to 80 weight percent, more preferably about 35 to 65 weight percent of the non-paying portion of the composition.

The composition comprises an epoxy component. Epoxy may vary in structure, molecular weight, epoxy equivalent (EEW) and number of epoxy groups per molecule of the skeleton and substituents. Suitable epoxies have a number average molecular weight of about 100 to 20,000, preferably 200 to 5,000, and have an EEW of about 50 to 10,000, preferably of about 100 to 2,500, and of about 1 to 40, preferably of 2 to 10 It has an average number of epoxy groups per molecule.

Particularly suitable epoxy resins are for example resorcinol, cathetazole, hydroquinone, bisphenol, bisphenol A, bisphenol F, bisphenol K, terabromobil bisphenol A, phenol-formaldehyde novolak resin, alkyl substituted phenol-formaldehyde Resin, phenol-hydroxybenzaldihydro resin, cresol-hydroxybenzaldihydric resin, dicyclopentadidine-phenolic resin, dicyclopentadi-substituted phenolic resin, terramethylbiphenol, terramethyl-terbromobiphenol, Diclisidyl ethers, such as these compositions, are included. Also alkylene oxide adducts or dihydroxy phenols, biphenols, bisphenols, halogen bisphenols, alkylate bisphenols, trisphenols, phenol-aldehyde novolac resins of one or more aromatic hydroxyl groups per molecule such as ethylene oxide, propylene oxide, Halogen phenol-aldehyde novolac resins, alkylate phenolaldehyde novolac resins, phenol-hydroxybezadelic resins, cresol-hydroxybenzaldehyde novolac resins, phenol-hydrosbenzaldehyde resins, cresol-hydrosbenzaldehyde compounds these Butylene oxide by-products of the compositions of are suitable. Also suitable are glycidyl ethers of compounds having an average of at least one aliphatic hydroxyl group per molecule, such as aliphatic polyols and polyether polyols. Also included are polyethylene glycol, polypropylene glycol, glycerol, polyglycerol, trimethylolpropane, butanediol, sorbitol, pentaerythritol and compositions thereof.

The epoxy component is preferably about 10 to 90 weight percent, preferably 20 to 80 weight percent, most preferably 35 to 65 weight percent of the non-paying portion of the composition. The molecular ratio of epoxy to anhydride is about 0.1 to 10, preferably 0.2 to 5, most preferably 0.5 to 2.0.

The composition comprises a nitrogen containing catalyst that promotes curing between epoxy and anhydride and optionally phenol. Preferably the catalyst is a secondary and tertiary amine, phosphine, arsine and combinations thereof. Preferred amine catalysts are, for example, imidazole, bezimidazole, 2-methyl imidazole, 2-ethyl-4-methylimidazole, 12-dimethylimidazole, 2-hexylimidazole, 2-cyclo Heximidazole, 2-Phenylimidazole, 2-Petyl-4-methylimidazole, 1-Betylimidazole, 1-aryl-2methylbezimidazole, 2-methyl-5, 6-benzimizol Dazole, 1-vinylimidazole, 1-allyl-2-methylimidazole, 2-cyanoimidazole, 2-chromolimidazole, 2-bromoimidazole, 1- (2-hydroxypropyl ) -2-methylimidazole, 2-phenyl-4, 5-dimethylrollidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-chloromethylbezimidazole, 2-hydrate Roxybenzimidazole, 2-ethyl-4-methyl imidazole, 2-cyclohexyl-4-methyl imidazole, 2-butoxy-4-allyl imidazole, 2-carboethyloxybutyl, 4-methyl- Imidazole, 2-tyl-4-mercaptoethyl imidazole and 2-phenyl imidazole. More preferred are 1-methyl imidazole, 2-ethyl imidazole, 2-ethyl-4-pentylthiimidazole, 2-phenylimidazole, 2-methyl-4-nitroimidazole, 4-methylimidazole. boil down. A more detailed description, including their properties and structural formulas of imidazole and benzimidazole, can be found in Klaus Hoffman's book, entitled "Imidazole and its Derivatives," published by Interscience Publishers, Inc, New York (1953). have.

Other preferred heterocyclic secondary and tertiary amine or nitrogen containing compounds which can be used herein are, for example, imidazoleidines, imidazolines, oxazoles, pyrroles, thiazoles, pyridine, pyrazine, morphphylline, pyridazine , Pyrimidine, pyrrolidin, pyrazole, quinoxaline, quinazoline, pyhalogen quinolin, furin, idazole, indole, indole, phenazine, phenazine, phenothiazine, pyrroline, indolin, blood Ferridine, piperazine and combinations thereof. Also suitable are 1,5-diazabicyclo [4.3.0] non-5-ene, 1,4-diazabicyclo [2.2.2] octane, 1,8-diazabicyclo [4.3.0] undec-7 Other alicyclic amines such as ene. Also preferred are benzyldimethylamine, N, N-dimethylamine, triethylamine, trimethylamine, N, N, N ', N'-tetramethylbutane-diamine, N, N, N', N'-tetramethylhexa Secondary and tertiary acyclic amines such as -diamine, triisooctylamine, N, N-diethiamine, triphenylanil and the like.

Suitable phosphines include, for example, triphenyl phosphine, trimethyl phosphine, tripropyl phosphine, tributyl phosphine, triphenyl phosphine, triheptyl phosphine, trioctyl phosphine, trinonyl phosphine, tridecyl phosphine Pin, tridodecyl phosphine, bis (diphenylphosphino) -methane, 1,2-bis (diphenylphosphino) -ethane, 1,3-bis (diphenylphosphino) -propane, 1,2- Bis (dimethylphosphino) -ethane, 1,3-bis (dimethylphosphino) -propane, and combinations thereof. Suitable arsines include, for example, triphenyl arsine, tributyl arsine and combinations thereof.

The catalytic amount is preferably provided in an amount of about 0.01 to 10% by weight, more preferably 0.02 to 5% by weight, most preferably 0.05 to 2% by weight of the non-part portion of the mixture.

The compound then comprises an aromatic hydroxyl containing compound such as a phenolic monomer or polymer or mixtures thereof. Suitable aromatic hydroxyl compounds that can be used herein include compounds having, for example, one or more phenolic hydroxyl groups per average molecule. Suitable compounds are, for example, dihydroxy phenols, bi-phenols, bisphenols, halogenated bisphenols, alkylated bisphenols, trisphenols, phenol-aldehyde resins, halogenated phenol-aldehyde novolak resins, alkylated phenol-aldehyde novolak resins. , Phenol-hydroxybezaldehyde resins, alkylated phenol-hydroxybenzaldehyde resins, dihydroxy phenols, biphenols, bisphenols, hydrogenated bisphenols, alkylated bisphenols, trisphenols, phenol-aldehyde novolac resins, halogenated Phenol-aldehyde novolac resins, alkylated phenol-aldehyde novolac resins, cresol-aldehyde novolac resins, phenol-hydrobezaaldehyde resins, cresol-hydroxybenzaldehyde resins, vinyl phenol polymers, ethylene oxide of any combination thereof, Propylene oxide, or butylene oxide products.

When a phenol containing compound or polymer is used, it is preferably provided in an amount of from 1 to 50%, more preferably from 5 to 40% and most preferably from 10 to 30, based on the weight of the non-solvent portion of the composition.

When a phenol containing compound or polymer is used, the catalytic amount is preferably from 0.01 to 10%, more preferably from 0.02 to 5%, most preferably from 0.05 to 2%, based on the weight of the non-solvent portion of the composition.

When phenol-containing compounds or polymers are used, the amount of minerals is preferably 0.05 to 20%, more preferably 0.2 to 10% and most preferably 0.5 to 5%.

When a phenol containing compound or polymer is used, the epoxy is preferably 10 to 90%, more preferably 20 to 70% and most preferably 30 to 60%, based on the weight of the non-compartment portion of the overall composition.

When a phenol palm oil compound or polymer is used, the molar ratio of epoxy to bound anhydride and phenolic is 0.1 to 10, more preferably 0.2 to 5, most preferably 0.5 to 2.0. The molar ratio of anhydride to phenolic is 20 to 0.5, preferably 10 to 1.0.

Other additives that may optionally be included in the composition of the present invention are fillers, colorants such as dyes and pigments, surfactants, heat resistant agents, plasticizers, antioxidants and the like. Known examples of colorants usable in the present invention include Permanent Yellow G (CI21095), Permanent Yellow GR (CI21100), Permanent Yellow DHG (CI21090), Permanent Rubine L6B (CI15850: 1), Permanent Pink F3B (CI12433 ), Hostaperm Pink E (73915), Hostaperm Red Violet ER (CI 46500), Permanent Carmine FBB (12485), Hostaperm Blue B2G (CI 74160), Hostaperm Blue A2R (CI 74160), and Printex 25. Surfactants that can be used include, for example, nonylphenoxy poly (ethyleneoxy) ethanol amounting to 10% by weight of the composition; Octylphenoxy ethanol. Plasticizers that can be used include, for example, phosphoric acid tri- (beta-chloroethyl) -ester up to 10% by weight of the composition; Stearic acid; Dicamphor; Polypropylene; Acetal resins; Phenoxy resins; And alkyl resins. Plasticizer additives improve the coating properties of the material and make films of flat and uniform thickness applicable to the substrate.

The photosensitive composition compound may be mixed in any suitable medium solvent and coated on the conductive foil by any convenient means. Solvents that can be used to prepare the photopolymerizable compositions of the present invention include alcohols such as methanol, ethanol, propanol, and butanol; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diisobutyl ketone and the like; Esters such as ethyl acetate, butyl acetate, amyl acetate, methyl formate, ethyl propionate, dimethyl phthalein, ethyl benzoate and methyl cellosolve acetate; Aromatic hydrocarbons such as toluene, xylene, benzene, ethylbenzene; Halogenated hydrocarbons such as carbon tetrachloride, trichloroethylene, chloroform, 1,1,1-trichloroethane, 1,2-dichloroethane, monochlorobenzene, chloronaphthalene; Ethers such as tetrahydrofuran, diethyl ether ethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether, and the like; Dimethylformamide, dimethyl sulfoxide and the like and mixtures thereof. Most preferred solvents are ethylene glycol monomomethyl ether, ethylene glycol monoethyl ether and dimethyl formamide, which dissolve the other components of the photographic coating. The amount of solvent that can be employed in the photopolymerizable composition of the present invention is present in the range of about 2050% to about 1000%, preferably about 50% to about 500% by weight of the non-solvent portion of the compound. The prepared optical insulation composition is then subjected to known techniques such as spin coating, slot die coating, injection, Meyer rod drawing, blade drawing, screen coating, curtain coating, dip coating, or spray coating. By coating on the foil of the substrate, but not limited to these techniques. Once the optically insulating composition coating is adhered to the substrate, the solvent evaporates to a coating weight of about 20 to about 200 g / m 2, more preferably about 40 to about 150 g / m 2, most preferably about 50 to about 100 g / m 2. Create A protective film may optionally be attached to the photoinsulating composition until ready to use. Suitable embossed photoinsulating resins are commercially available, for example under the trademark AZ-P4620 from Clariant Corporation of Somerville, NJ.

As shown in Fig. 1, a photosensitive element comprising a conductive foil 2 and a photosensitive insulating composition 4 is attached onto a conductive wiring pattern located on the surface of the next substrate 8. Suitable substrates are known in the art of printed circuit boards such as polyesters, polyimides, epoxies, cyanate esters, teflon and silicone. Each of the substrates may be reinforced by glass fibers or glass polymer fibers. The conductive wiring pattern may be a metal such as copper, copper alloy, aluminum, aluminum alloy, where copper is most preferred. Within the scope of the present invention, the term metal wiring includes electrically bonding pads. These can be prepared by known photolithography and etching processes. Preferably, the photosensitive element is attached to the metal wiring and the substrate by the lamination means. That is, the photosensitive element and the substrate pass through a nip of a set of heating rollers or a heat press of a lamination apparatus having a temperature of about 90 ° C to about 150 ° C.

As shown in Fig. 2, photoresist layer 10 is attached on the opposite side of foil 2. It should be noted that the insulating composition layer 4 is now located above and between the conductive wires 6. The photoresist may be embossed or intaglio. Useful embossed photoresists include the compositions described above as useful for the photosensitive insulating composition. Useful embossed photoresists are known in the art and include embossed o-quinone diazide irradiation light sensitizers. o-quinone diazide irradiation light sensitizers include o-quinone-4- or-5-sulfonyl-diazide described in US Pat. Nos. 2,797,213, 3,106,465, 3,148,983, 3,130,047, 3,201,329, 3,785,825, and 3,802,885. When o-quinone-diazide is used, preferred binding resins include expandable binding resins which are poorly water soluble, hydrated alkaline soluble or preferably novolak resins. The production of novolak resins is known in the art. Processes for their preparation include the application and chemistry of phenolic resins incorporated herein by reference, Knop A. and Scheib, W .; Chapter 4 of Springer Verlag, New York, 1797. Suitable novolak resins are sparingly water-soluble, hydrated alkali-soluble resins having a molecular weight ranging from about 6000 to about 14000, more preferably from 8000 to about 12000. The amount of sensitizer and binder may vary depending on the experimental results of those skilled in the art depending on the desired product properties. The compound is mixed with a suitable solvent such as those listed above, coated on a conductive foil and dried. Suitable photoresist compositions are described in US Pat. No. 4,588,670. Engraved photoresist is also widely commercially available. The photoresist may also be a dry film photoresist, such as a MacDermid Aqua Mer dry film photoresist.

The photoresist is then exposed to form an image in actinic radiation. As used herein, " actinic radiation light " is formed from the spectrum of visible, ultraviolet or infrared light, and electron beams, ions or neutral beams or x-ray irradiation light. The actinic radiation may be non-scattered light, such as laser light, or in the form of scattered light. The source of actinic light, and the exposure process, time, wavelength, and intensity may vary depending on the desired degree of photo-response and other factors well known to those skilled in the art. Such conventional photo-reaction processes and their operating parameters are known in the art. The source of actinic radiation and the wavelength of the irradiation light are varied over a wide range and any conventional wavelength and source can be used. It can be developed by exposure to ultraviolet irradiation light in the range of 300 to 550 nanometers by means of a photo mask or computer directed laser pattern. Suitable ultraviolet sources include carbon arc lamps, xenon arc lamps, mercury vapor lamps (metal halide lamps) doped with metal halides, fluorescent lamps, arcon filament lamps, electric flash lamps, and photo flood lamps. Exposure is performed to provide sufficient actinic energy to allow photochemical changes in the image area where the photosensitive composition is exposed through the mask and prevents substantial photochemical changes in the non-imaging area. The exposed photoresist is then developed and thereby the removed and unremoved image portions are formed such that the removed image portions are located at least on top of some conductive wiring. Typical developers may be alkaline or neutral and have a pH range of about 5-12. The developer is preferably formed from an aqueous solution of hydroxide, phosphate, silicate or metabisulfide and / or monoethanolamine. Such non-exclusive examples include alkali metal hydroxides, mono-, di-, and tri-alkali metal phosphorates, sodium silicates, alkali metal metasilicates, and alkali metabisulfates. The developer may also contain surfactants, buffers, solvents, and other additives known in the art. Other developers can be synthesized from common organic solvents.

Next, the portion of the conductive foil underlying the removed image forming portion of the photoresist is removed without removing the underlying photosensitive insulating composition. The conductive foil to be removed can be removed by known techniques such as etching and laser removal. 3 shows a conductive foil with the removed image portion after removing the rest of the photoresist layer.

Then, by the manner described above, the photosensitive insulating composition portion is exposed to image to actinic radiation through the removed portion of the conductive foil using the conductive foil as a conformal mask. The exposed portion 12 of the insulating layer is shown in FIG. Optionally, the photosensitive insulating composition can be heated to reduce developer solubility of the unexposed portions. The heating may be at a temperature of about 90 ° C. to about 170 ° C. for about 1 minute to about 30 minutes. Then, the photosensitive insulating composition is developed in a manner similar to that described above, whereby the removed image portion and the removed image portion are formed so that the removed image portion forms via 14 in the conductive wiring 6 as shown in FIG. do.

The non-removed portion of the photoresist insulating composition is then cured, preferably thermally cured. Curing may be performed for about 10 to 120 minutes at a heating temperature of about 90 ° C to about 250 ° C.

Next, the conductive wiring is electrically connected to the portion of the conductive foil through the vias. This is preferably done by plating metal 16 through vias from the conductive wiring 6 to the conductive foil 2 portion as shown in FIG. This is done by performing electroless metal plating from the conductive wiring to the portion of the conductive foil, optionally followed by a metal electroplating step known in the art. Alternatively, vias can be purchased with conductive pastes such as U-300 available from Epoxy Technology Inc. or organo-metallic compounds such as Ormet available from Toranaga Technologies of Carlstadt, California. Next, the conductive foil is preferably patterned by a method known in the art, thereby providing a conductive foil wiring pattern. Optionally, the process step may be repeated one or more times to form a multilayer structure by attaching another photosensitive element on a previously patterned conductive foil interconnect made by the process described above. Optionally, the entire process may be performed one or more times on both sides of the substrate to provide a double-sided printed circuit board.

In another embodiment of the present invention, the above photosensitive element is attached on the pattern of conductive wiring 6 on the surface of the substrate 8 as previously described in FIG. Next, as shown in FIG. 7, the entire conductive foil 2 is removed using a technique such as etching or laser cutting, leaving only the photosensitive insulating composition 4 on the conductive wiring 6 on the surface of the substrate 8 and therebetween. This has the advantage of providing a mat face with a fine rough structure for the photosensitive insulating composition which allows the copper to adhere well later to the insulating layer. As shown in Figs. 8 and 9, the photosensitive insulating composition 4 is then developed to be imaged to actinic irradiated light so that an image portion removed therefrom is present on at least some of the conductive wires, The removed and unremoved image portions of the insulating composition are formed to form vias 14. Next, the unremoved portion of the photosensitive insulating composition is cured. Next, as shown in FIG. 10, an electrically conductive layer 18, such as copper, is formed on the insulating composition, preferably by plating, and forms an electrical connection from the conductive wiring 6 to the electrically conductive layer 18 through vias 16. . Next, electrically conductive layer 18 is patterned from the electrically conductive layer material to form a conductive wiring pattern by means known in the art.

The following is a non-limiting example for illustrating the present invention.

Example 1

The photosensitive resin was mixed, at room temperature, under yellow light, 2 epoxy monomers, 8% by weight EPON 1001F by Cell Chemicals, 24% by weight styrene maleic anhydride oligomer by Elf Autospun Inc., light Prepared by mixing the asset, 2.5 wt% CD 1011 from Sartomer, 0.3 wt% 2-ethyl-4-methylimidazole (EMI), and a solvent, 49.2 wt% methyl ethyl ketone (MEK). This monomer mixture is coated to a thickness of 50 to 100 μm on a copper foil substrate. The coating is baked in a 90 ° C. oven for 5 minutes to form a trackless dry film. The photosensitive dry film covered with the backside by the previously prepared copper foil is laminated to the circular inner layer substrate by a hot roll laminator at a roll temperature of about 120 ° C. In the same step an additional layer of MacDermid Aqua Mer MP200 dry film photoresist is deposited on top of the copper foil. The overall structure is cooled and exposed to UV light through essentially clean artwork with dark areas of via formation sites. The dry film photoresist exposes the copper foil so that a via is formed under the area covered by the dark area of the mask. The exposed copper foil is then etched using a copper chloride etchant at 50 ° C. After rinsing and drying, the panels are exposed to UV of 1 J / cm 2. The exposed panels are postbaked at 140 ° C. for 5 minutes, and after cooling the panels are immersed in a 10% aqueous solution of monoethanolamine (MEA) to remove the dry film photoresist and form via holes in the photosensitive layer up to the copper pad in the next layer. It is locked and sprayed into it. The holes are desmeared with carium permanganate, washed with conventional cleaning liquid, rinsed and dried. The panel is then sintered at 170 ° C. for 2 hours to cure the dielectric layer. Following curing, the panel is plated with a conventional electroless copper solution accompanied by additional electroplating of 1-2 mil copper. Therefore, conductive vias are formed between the two copper layers. Outer layer circuits are manufactured by conventional printing and etching processes. The photoresist dry film is deposited on a copper plane and imaged through UV exposure and development. The copper layer is etched with a conventional copper etchant. After etching, the photoresist film is peeled off with a conventional stripper and the panel is cleaned with a conventional cleaning liquid. The process is repeated as many times as necessary to produce a printed circuit board having the required number of layers of overlap. The board is finally finished by the formation of additional layers required such as solder mask, solder, electroless gold and the like.

Example 2

The photosensitive resin is composed of two epoxy monomers, 16% by weight of EPON by Shell Chemical Company and 8% by Dencol EX-614B by Nagase Chemical, styrene mulleic acid. Anhydride oligomers, 24% SMA 1000 by Elf Autochem Inc., CD 1011 by Sartomer Company, 0.2% 2-ethyl-4-methylimidazole (EMI), and solvent, 49.8% Provided by mixing methyl ethyl kentone (MEK) at room temperature and under yellow light. This monomer mixture is coated on a copper film substrate to a thickness of 50 to 100 μm. The coating is baked at 90 ° C. for 5 minutes to form a dry dry film. The photosensitive dry film baked by the copper film provided as above is laminated to the circuitry inner layer by vacuum pressure at about 100 ° C. McDermid Acure Mare MP200 dry film photoresist is deposited on top of a copper film by a 115 ° C. hot roll laminator. The entire structure is cooled and the dry film photoresist is exposed to UV light through an essentially clean artwork having a dark area of the desired via location. The dry film photoresist is developed and exposes the copper film so that vias are formed under the areas covered by the dark areas of the mask. The exposed copper film is etched using cupric chloride etchant at 50 ° C. After washing and drying, the panels are exposed to UV at 1 J / cm ² . The exposed panels were presintered at 140 ° C. for 5 minutes, and the panels strip 10% monoethanol at 50 ° C. for 5 minutes to strip dry film photoresist and develop through the holes in the photosensitive insulating layer down to the copper pad of the next layer. Sprayed in an aqueous lamin (MEA) solution. After washing, rinsing and drying, the panels are baked at 170 ° C. for 2 hours to cure the insulating layer. After curing and plated with conventional electroless copper solution, the panel additionally electroplated 1-2 millimeters of copper. Then a conductive via is formed between the two copper layers. Outer layer circuits are manufactured by conventional printing and etching processes. The photoresist dry film is deposited on a copper plane and imaged through UV exposure and development. The copper layer is etched with a conventional copper etchant. After etching, the photoresist film is stripped with a conventional stripper and the panel is washed with a conventional cleaning solution. The process is repeated as many times as necessary to produce a printed printed circuit board having a desired number of layers. The board is finally completed by the formation of additional layers required such as solder mask, solder, electroless gold and the like.

Example 3

The photosensitive resin is a single epoxy monomer, Dencol EX-512 with 8% Nages Chemical, styrene mulle anhydride oligomer, 24% SMA 1000 by Elf Autochem Inc., Photoacid, CD by Satomer Company 1011, 0.2% 2-ethyl-4-methylimidazole (EMI), and a solvent, 49.8% methyl ethyl kentone (MEK), are provided by mixing under room temperature and yellow light. This monomer mixture is coated on a glass substrate to a thickness of 50 to 100 μm. The coating is baked in a 90 ° C. oven for 5 minutes to form a dry dry film. The photosensitive dry film baked by the copper film provided as described above is laminated to the circuitry inner layer substrate by vacuum pressure at about 100 ° C. The copper film is etched using cupric chloride etchant at 50 ° C. After hemging and drying, the panels are exposed to UV throughout the work to have a desired structure at 1 J / cm ² . The exposed panel is presintered at 140 ° C. for 5 minutes, and after cooling, a 10% monoethanolamine (MEA) anhydride solution at 50 ° C. for about 3 minutes to extend the via hole of the photovoltaic layer below the copper pad in the next layer. Developed. After washing, hemging and drying, the panels are baked at 170 ° C. for 2 hours to cure the insulating layer. After curing, the panels are plated with a conventional electrodeless copper solution, followed by an additional 1 to 2 millimeters of copper. Conductive vias are formed between the two copper layers. The outer layer circuit is manufactured by conventional printing and etching processes. The photoresist dry film is deposited on a copper plane and imaged through UV exposure and development. The copper layer is etched with a conventional copper etchant. After etching, the photoresist film is stripped with a conventional stripper and the panel is cleaned using a conventional cleaning solution. The process is repeated as necessary to produce a printed circuit board having a desired number of layers. The board is finally completed by the formation of the required additional layers such as solder mask, solder, electroless gold and the like.

Example 4

The photosensitive resin is composed of two epoxy monomers, EPON 1001F with 8% by weight Shell Chemical Company and Dencol EX-512 with 16% Nagas Chemical, Styrene Merlin anhydride oligomer, SMA by 24% Elf Autochem 2000, photoacid, CD 1011 by 2% Satomer Company, 0.2% 2-ethyl-4-methylimidazole (EMI), and solvent, 49.8% methyl ethyl ketone (MEK) at room temperature and yellow It is provided by mixing under light. This monomer mixture is coated on a glass substrate to a thickness of 50 to 100 μm. The coating is baked in a 90 ° C. oven for 5 minutes to form a dry, dry film. The photosensitive dry film baked by the copper film provided as described above is laminated to the circuitry inner layer by a vacuum pressure of about 100 ° C. The copper film is etched using cupric chloride etchant at 50 ° C. After hemging and drying, the panel is exposed to UV through a plate having a clean area with the desired via position at 1 J / cm ² . The exposed panel is presintered at 140 ° C. for 5 minutes, and after cooling, a 10% monoethanolamine (MEA) anhydride solution at 50 ° C. for about 3 minutes to extend the via hole of the optical insulation layer below the copper pad of the next layer. Developed. After washing, rinsing and drying the panels are baked at 170 ° C. for 2 hours to cure the insulating layer. After curing, the panel is plated with a conventional electroless copper plating solution and then 1 micron of additional copper is plated in a conventional manner. Conventional dry film photoresists are laminated to a panel, exposed through a mask and developed according to standard industry practice. The pattern on the mask leaves photoresist on the circuit so that no trace of trace is generated. Copper is only exposed where it is desired to form a circuit. Additional conventional electroplating steps are performed to increase the copper thickness to an additional 1-2 millimeters in the exposed area. The photoresist is stripped and 2 microns of copper are etched anywhere and the panel is washed with a conventional cleaning solution. This removes the thin copper layer underneath the photoresist during the final plating step while leaving thicker copper bulk plated to form the outer layer circuit. The process is repeated as necessary to produce a printed circuit board having a desired number of layers. The board is completed by the formation of additional layers such as the solder mask protective layer.

It will be appreciated that as described above, high density, multilayer printed circuit boards can be fabricated by constructing microvias with an embossed photoimageable insulating material.

Claims (31)

(a) attaching a photosensitive element having an embossed photosensitive insulating composition on the surface of the conductive foil to a pattern of conductive wiring on the surface of the substrate such that the photosensitive insulating composition is positioned on the conductive wiring; (b) attaching a photoresist layer on opposite surfaces of the foil; (c) exposing the photoresist to actinic radiation to form an image and developing the photoresist so that the removed image portion is at least partially positioned over the conductive wiring so that the removed image portion of the photoresist is Forming an unremoved image portion; (d) removing the portion of the conductive foil underlying the removed image forming portion of the photoresist without removing the underlying photosensitive insulating composition; (e) exposing the photosensitive insulating composition portion as a whole to actinic radiation through the removed portion of the conductive foil, selectively heating the photosensitive insulating composition to reduce developer solubility of the unexposed portion of the photosensitive insulating composition, Developing the photosensitive insulating composition thereby removing only a portion of the photosensitive insulating composition underlying the removed portion of the conductive foil, thereby forming a via in the conductive wiring; (f) curing the unremoved portion of the photosensitive insulating composition; (g) electrically connecting the conductive wires to the conductive foil portion through the vias; And (h) patterning the conductive foil to form a conductive foil wiring pattern. The method of claim 1, wherein the step (a) to step (h) is repeated at least once by attaching another photosensitive element according to step (a) onto the previously patterned conductive foil wiring in step (h). Printed circuit board manufacturing process, characterized in that it further comprises. The process of claim 1 wherein step (g) comprises plating a metal through the via from the conductive wire to the portion of the conductive foil. The process of claim 1, wherein step (g) comprises performing electroless metal plating through the via from the conductive wiring to the portion of the conductive foil. The process of claim 1, wherein step (g) comprises performing electroless metal plating through the via from the conductive wiring to the portion of the conductive foil and performing the next metal electroplating step. . The process of claim 1 wherein step (g) comprises embedding said vias with a conductive paste or organometallic compound. The process of claim 1 wherein step (f) is performed by heating to a temperature of about 90 ° C to about 250 ° C. The process of claim 1 wherein the foil comprises copper, a copper alloy, aluminum or an aluminum alloy. The process of claim 1, wherein the conductive wiring comprises copper, a copper alloy, aluminum, or an aluminum alloy. The process of claim 1 wherein the substrate comprises an insulating material. The process of claim 1 wherein the photoresist is a negative photosensitive composition. The process of claim 1, wherein the photoresist is of a relief photosensitive composition. The process of claim 1 wherein the substrate comprises a material selected from the group consisting of polyester, polyimide, epoxy, cyanate ester, silicon, gallium arsenide and teflon. The method of claim 1, wherein the relief photosensitive insulating composition comprises at least one photoacid generator, at least one organic acid anhydrous monomer or polymer, at least one epoxy, capable of producing an acid upon exposure to actinic radiation. A process for producing a printed circuit board comprising at least one nitrogen-containing curing catalyst and an optional aromatic hydroxyl containing monomer, polymer or mixtures thereof. 15. The process of claim 14, wherein the photoacid generator is an onium compound. 15. The printed circuit board of claim 14, wherein the photoacid generator is selected from the group consisting of sulfonium compounds, iodonium compounds, diazonium compounds, organic compounds having photoactive halogen atoms, and mixtures thereof. Manufacturing process. 15. The process of claim 14 wherein the acid anhydrous polymer has a number average molecular weight of about 500 to about 50000. 15. The method of claim 14, wherein the acid anhydride polymer is selected from the group consisting of styrene-maleic anhydride, styrene-alkyl methacrylate-itaconic anhydride, methyl methacrylate-butyl acrylate-itaconic anhydride, butyl acrylate-styrene-maleic. Anhydride, dodecynyl succinic anhydride, trimellitic anhydride, chloroendic anhydride, phthalic anhydride, methylhexahydrophthalic anhydride, 1-methyl terahydrophthalic anhydride, hexahydrophthalic anhydride, methylnadic anhydride, Process for manufacturing a printed circuit board, characterized in that selected from the group consisting of methyl butenyl tetrahydro phthalic anhydride, benzophenone terracarboxylic dianhydride, methylcyclohexene dicarboxylic anhydride and mixtures thereof. 15. The method of claim 14, wherein the epoxy has a number average molecular weight in the range of about 100 to about 20000, an epoxy equivalent mass of about 50 to about 10000, and an average number of epoxy groups per molecule of about 1 to about 40. Printed Circuit Board Manufacturing Process. 15. The method of claim 14, wherein the epoxy is resorcinol, ketecol, hydroquinone, biphenol, bisphenol A, bisphenol F, bisphenol K, tetrabromobisphenol A, phenol-formaldehyde novolak resin, alkyl Substituted phenol-formaldehyde resin, phenol-hydroxybenzaldehyde resin, cresol-hydroxybenzaldehyde resin, dicyclopentadiene-phenol resin, dicyclopentadiene-substituted phenol resin tetramethylbiphenol, tetramethyl- tetrabromobi Process for producing a printed circuit board comprising phenol, diglycidyl ether of a mixture thereof. 15. The process of claim 14 wherein the nitrogen-containing catalyst is selected from the group consisting of secondary amines, quaternary amines, phosphines and amines and mixtures thereof. The method of claim 14, wherein the nitrogen-containing catalyst is imidazole, imidazolidine, imidazoleline, oxazole, pyrrole, thiazole, pyridine, pyrazine, morpholine, pyridazine, pyrimidine, Printed circuit board, characterized in that selected from the group consisting of purine, indazole, indole, indazine, phenazine, phenazine, phenothiazine, pyrroline, indolin, piperidine, piperazine and mixtures thereof Manufacturing process. The compound according to claim 14, wherein the aromatic hydroxyl-containing compound is a dihydroxyl phenol, bi-phenol, bisphenol, halogenated bisphenol, alkylated bisphenol, triphenol, phenol-aldehyde resin, halogenated phenol-aldehyde novolak resin, alkylated phenol- Aldehyde novolac resins, phenol-hydroxybenzaldehyde resins, alkylated phenol-hydroxybenzaldehyde resins, ethylene oxide, propylene oxide, or butylene oxide additives of dihydroxy phenols, biphenols, bisphenols, halogenated bisphenols, alkylated bisphenols , Trisphenol, phenol-aldehyde novolak resin, halogenated phenol-aldehyde novolak resin, alkylated phenol-aldehyde novolak resin, cresol-aldehyde novolak resin, phenol-hydroxybenzaldehyde resin, cresol-hydroxybenzaldehyde resin, Vinyl phenol polymers, and mixtures thereof A printed circuit board manufacturing process, characterized by. A printed circuit board manufactured by the process of claim 1. A printed circuit board manufactured by the process of claim 14. (a) depositing a layer of relief photosensitive composition on the surface of the conductive foil thereby forming a photosensitive element; (b) attaching the conductive foil on the conductive wiring pattern on the surface of the substrate via the photosensitive insulating composition; (c) attaching a photoresist layer on opposite surfaces of the foil; (d) exposing the photoresist to actinic radiation to form an image, selectively heating the photosensitive insulation composition to reduce developer solubility of the unexposed portion of the photosensitive insulation composition, and developing the photoresist to thereby Forming a removed image portion and a non-removed image portion of the photoresist such that the image portion removed by the at least part is located above the conductive wiring; (e) removing the portion of the conductive foil underlying the removed image forming portion of the photoresist without removing the underlying photosensitive insulating composition; (f) exposing the photosensitive insulating composition portion as a whole to actinic radiation through the removed portion of the conductive foil, selectively heating the photosensitive insulating composition to reduce developer solubility of the unexposed portion of the photosensitive insulating composition, Developing the photosensitive insulating composition thereby removing only a portion of the photosensitive insulating composition underlying the removed portion of the conductive foil, thereby forming a via in the conductive wiring; (g) curing the unremoved portion of the photosensitive insulating composition; (h) electrically connecting the conductive wires to the conductive foil portion through the vias; And (i) patterning the conductive foil to form a conductive foil wiring pattern. 27. The method of claim 26, wherein repeating steps (a) to (i) at least once by attaching another photosensitive element according to step (a) onto the previously patterned conductive foil wiring in step (i). Printed circuit board manufacturing process, characterized in that it further comprises. (a) attaching a photosensitive element having an embossed photosensitive insulating composition on the surface of the conductive foil to a pattern of conductive wiring on the surface of the substrate such that the photosensitive insulating composition is positioned on the conductive wiring; (b) removing the conductive foil; (c) exposing the photoresist to actinic radiation to form an image, selectively heating the photosensitive insulation composition to reduce developer solubility of the unexposed portion of the photosensitive insulation composition, and developing the photoresist to thereby Forming a removed image portion and a non-removed image portion of the photoresist such that the image portion removed by the at least part is located above the conductive wiring; (d) curing the non-removed portion of the photosensitive insulating composition; (e) simultaneously forming an electrically conductive layer on the non-removed portion of the photosensitive insulating composition and electrically connecting the conductive wiring to the conductive foil portion through the via; And (f) patterning the electrically conductive layer to form a conductive wiring pattern. 29. The method of claim 28, further comprising repeating steps (a) to (f) at least once by attaching another photosensitive element according to step (a) onto the previously patterned conductive wiring in step (f). Printed circuit board manufacturing process comprising a. (a) depositing a layer of relief photosensitive composition on the surface of the conductive foil thereby forming a photosensitive element; (b) attaching the conductive foil on the conductive wiring pattern on the surface of the substrate via the photosensitive insulating composition such that the photosensitive insulating composition is positioned on the conductive matrix; (c) removing the conductive foil; (d) exposing the photoresist to actinic radiation to form an image, selectively heating the photosensitive insulation composition to reduce developer solubility of the unexposed portion of the photosensitive insulation composition, and developing the photoresist to thereby Forming a removed image portion and a non-removed image portion of the photosensitive insulating composition such that the image portion removed by the at least part is located above the conductive wiring; (e) curing the unremoved portion of the photosensitive insulating composition; (f) simultaneously forming an electrically conductive layer on the non-removed portion of the photosensitive insulating composition and electrically connecting the conductive wiring to the electrically conductive layer through the via; And (g) patterning the electrically conductive layer to form a conductive wiring pattern. 31. The method of claim 30, wherein repeating steps (a) to (g) at least once by attaching another photosensitive element according to step (a) onto the previously patterned conductive foil wiring in step (g). Printed circuit board manufacturing process, characterized in that it further comprises.