JPH0222372B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a method for laminating successive layers on a substrate;
It particularly relates to an integrated lamination method in which the laminated layers are automatically trimmed. U.S. Pat. No. 3,469,982 discloses applying a photopolymerizable layer supported on a support film to a surface, exposing the layer imagewise, stripping the support film and washing away the unexposed portions of the layer. A photoresist process is disclosed that includes leaving a resist image that protects the surface from processes such as etching or plating. This U.S. patent discloses implementing a photoresist process by solution coating a photopolymerizable composition onto a support film, subsequent drying, and lamination of the resulting dry coating to a surface such as a copper-coated printed circuit board (example). is disclosed. However, in industrial practice dry photopolymerizable coatings, which must remain adhered to the support during storage and shipping, are always attached to the support film and cover sheet, as disclosed in the examples of this patent. Sandwiches are available in sandwich form.
This allows the photoresist manufacturer to roll up the sandwich and supply it as a compact, easy-to-handle roll to users such as printed circuit manufacturers. This cover sheet allows the user to unwind the roll. Without a cover film, the photopolymerizable layer would be pressed against the back side of the support film, causing adhesion of the layers. As a result, the film cannot be rewound without damaging the photopolymerizable layer. In use, the cover sheet is peeled off and discarded, and the photoresist is then processed as described above. US Pat. No. 3,782,939 discloses that a cover sheet is necessary due to the tackiness of the photopolymerizable layer. In practice, this layer is not necessarily sticky to the touch, but may adhere under pressure, for example when it is rolled up into a roll. The equipment used to carry out the photoresist process generally consists of several separate parts of the equipment, such as a cleaner,
From scrubbers for cleaning copper-clad circuit boards, ovens for preheating the boards, roll-type laminators and exposure (actin radiation) stations and solvent development equipment that apply heat to the photoresist and the boards as they are laminated together. It is configured. Typically, manual transportation and positioning of circuit boards was required between each piece of equipment. This was expensive and less reproducible than desired, leading to yield losses in the process. Various attempts have been made to automate the photoresist process, but automation has been employed only to a limited extent. U.S. Pat. No. 3,547,730 discloses a method and apparatus for automating a photoresist process, including an apparatus for sequentially dispensing molded articles, such as circuit boards, and a laminating machine for receiving the boards and laminating a photosensitive layer thereto. are doing. The successively laminated plates are bonded together by a web of support film and photosensitive layer extending between the plates, as shown in FIG. 2, and the upper and lower web layers are bonded together. They are stacked to form a "hinge" (column 5, lines 35-39). Then roll 1
2 and 13, the support film is peeled off. This peeling imparts a forward motion to the circuit board bringing it into abutting relationship with the preceding board and forcing it into the exposure unit. This web of photosensitive layer, which remains extended between successive plates after peeling off the support film, folds upon itself in a "hinged" fashion when the plates are butted together. This hinge can be trimmed with a knife before entering the exposure unit. U.S. Pat. No. 3,547,730 also describes cleaning the circuit board intermediate the supply station and the lamination station, preheating the board and/or the photosensitive layer between their respective supply and lamination stations, and A roll 10 for peeling the cover sheet prior to lamination is also disclosed. U.S. Pat. No. 4,025,380 discloses sequential feeding of circuit boards onto a conveyor. This conveyor passes the circuit board through an infrared preheater and then through a sensor switch. This sensor switch controls the operation of the laminating rolls and cutting equipment that cut the photosensitive layer to the desired length prior to lamination and laminate the cut sheets (layers) to the circuit board. This patent also discloses a roll 63 for stripping the cover film prior to lamination. Improvements to specific process steps are also disclosed.
U.S. Pat. No. 3,629,036 discloses that the high temperatures required to laminate a photoresist to a substrate have the disadvantage of limiting the types of photoresist and substrate materials that can be used, and produce poor bonding to the substrate. This is disclosed.
This patent attempts to solve these problems by first applying a dissolved resist solution to the substrate and then performing the lamination followed by room temperature lamination. This patent provides a release layer between the photoresist layer and its support film to allow the film to be peeled away from the photoresist layer after lamination. U.S. Pat. No. 3,794,546 discloses a method for delaminating a support film of a photocurable element from at least an uncured portion of an imagewise exposed photocurable layer laminated to a receptor sheet. discloses the use of an adhesive web for the adhesion of . U.S. Pat. No. 4,075,051 discloses a method for self-trimming a photoresist layer deposited on a substrate, ie removing the portion of the layer extending beyond the edges of the substrate without any cutting step. This applies a liquid weakening agent to at least that portion of the layer, but perhaps to the entire layer, by pre-wetting the substrate with the agent, and then the cohesive strength of the cover sheet (supporting film) or layer. This is achieved by peeling off the auxiliary permeable sheet (as a result of the weakening agent), which has greater adhesion to the layer than the auxiliary permeable sheet. The portion of the layer extending beyond the edge of the substrate is cut along the edge of the substrate by the action of peeling off the cover sheet or permeable sheet and removed along with the sheet. A weakening agent is a solvent for the photoresist or a softening agent for it. This patent discloses the use of conventional roll-type laminators and pressure and heat for adhesion of photoresist layers to substrates. Although prior art methods of lamination are satisfactory for many applications, there is a need for even more accurate and uniform lamination methods, especially when printed circuit boards with very high linear densities are being manufactured. ing. The present invention comprises the following sequence of steps: (1) advancing a continuous layer of a light-sensitive organic polymer composition supported on one side by a peelable polymeric film and a first substrate to the nip of a set of lamination rolls; (2) bringing the unsupported surface of the supported layer into contact with the surface of the substrate element under pressure in a nip to cause lamination of said layer to the surface of the substrate element; (3) optionally removing the support film from the layer as the laminated substrate element emerges from the nip of the lamination roll and continuing advancement of the laminated substrate element until the support film is completely removed from the laminated layer; (4) at the rear edge of the substrate in a direction transverse to the direction of travel and along its longitudinal axis in the direction of travel so as to exceed the breaking strength of the laminated layers and their support film, if any; applying light to the surface of each member of the series of substrate elements, including stretching the laminated substrate elements along the series; An integrated method for laminating successive layers of a sensitive composition and trimming this layer from at least one of the lateral edges of the laminated substrate element. In a preferred embodiment of the invention, the support film is removed from the ply by bending the film at an obtuse angle to the backside along the longitudinal axis of the advancing ply as the ply exits the nip of the lamination roll. .
The radius of the bend is small enough to overcome the breaking strength of the layer on the leading edge of the substrate element. Other advantages and details of the invention will become apparent with reference to the accompanying drawings. FIG. 1 is a schematic diagram illustrating a preferred application of the method of the invention in a continuous lamination process. FIG. 2 is a schematic cross-sectional view of a preferred substrate treatment method prior to laminating the photosensitive layer. Figures 3A and 3B are schematic diagrams illustrating in cross-section a preferred method for trimming the photosensitive layer from the leading edge of a substrate laminated by this method. and the fourth
The figure is a schematic diagram illustrating in cross-section a preferred method for trimming the photosensitive layer from the rear edge of a substrate laminated according to the method of the invention. A Photosensitive Layer Element The present invention can be advantageously used in laminating a wide variety of thermoplastic layers. The present invention is particularly useful for laminating photosensitive resist elements to substrates used in printed circuit board manufacturing. The present invention also provides
It is also useful for laminating photosensitive layers to substrates in the manufacture of lithographic printing plates. Various types of photosensitive film resists may be used in the practice of the present invention.
In general, photocurable resists that work as negatives are
A photopolymerizable film of the type disclosed in U.S. Pat. No. 3,469,982 and an optical cross-linking element of the type disclosed in U.S. Pat. No. 3,526,504. The resist elements which act as positive may be of the photo-solubilizing type, e.g. the o-quinonediazide elements of US Pat. No. 3,837,860, or of the photosensitizing type, e.g. the bisdiazonium salts of US Pat. No. 3,778,270, or of the British patent No.
1547548 may be a nitroaromatic compound. The photosensitive layer used in this method is preferably such that it is soluble in an aqueous alkaline solution and thereby 1% by weight in an aqueous alkaline solution at 29.4° C. with a spray pressure of, for example, 1.38 Kg/cm ² .
It is aqueous alkaline processable in the sense that it can be developed with Na ₂ CO ₃ for 90 seconds. Elements containing an imageable, non-blocking, photopolymerizable base layer on a releasable support, such as those described in US Pat. No. 1,536,39, are preferably used. Alternatively, the remaining surface of the supported photopolymerizable base layer can be protected with a removable cover sheet, especially if the photopolymerizable layer is tacky. Alternatively, if the element is stored in roll form, its base layer surface can be protected by the adjacent back surface of the support. The photosensitive composition is present in a dry film thickness of about 0.0003 inch (~0.0008 cm) to about 0.01 inch (~0.025 cm) or more. Suitable releasable supports, preferably having a high degree of dimensional stability against temperature changes, are high polymers such as polyamides, polyolefins, polyesters,
Constructed from vinyl polymers and cellulose esters, and ~0.00025 inches (~0.0006 cm)
There is a wide variety of films to choose from that can have thicknesses of 0.008 inches (0.02 cm) or more. A particularly suitable support is approximately 0.001 inch (~0.001 inch)
It is a transparent polyethylene terephthalate film with a thickness of 0.0025 cm). When the invention is used for laminating photosensitive layers, it is essential that the adhesion A ₁ of the unexposed photosensitive layer to the polymeric support is greater than the breaking strength B of the photosensitive layer without support. It is. Similarly, the adhesion A ₂ of the unexposed photosensitive layer to the substrate must be greater than or equal to the breaking strength B of the unsupported photosensitive layer. Furthermore, the adhesion A ₂ of the photosensitive layer to the substrate must also be greater than its adhesion A ₁ to the polymer support, since the polymer support must be peelable from the laminated photopolymerizable layer. It won't happen. Expressed mathematically, A ₂ >
A ₁ > B. A proper balance of these adhesive and puncture strengths in a photosensitive system can be obtained by adjusting the relative proportions of monomer and binder. As mentioned above, the photosensitive layer is also preferably relatively hard and composited to be non-block-forming. That is, it does not stick to itself or to the film support with an adhesive strength greater than the cohesive strength of the layer. The result of this is that no cover sheet is required to prevent the layer from sticking to the support film while in the rolled up position relative to the photosensitive element. This saves material costs and eliminates the need for peeling off the cover sheet and discarding the peeled cover sheet. If this element does not contain a removable protective cover sheet, and if it is stored in roll form, apply a thin release layer of a substance such as wax or silicone to the back side of the releasable support. Other protection against blocking of the photopolymerizable substrate may optionally be provided to prevent blocking of the photopolymerizable substrate. Alternatively, the adhesion to the coated photopolymerizable layer can be preferentially increased by flame- or discharge-treating the surface of the support to be coated. Suitable removable protective cover sheets, if used, may be selected from the same group of high polymeric films as described above, and may have the same wide range of thicknesses. A 0.001 inch (~0.0025 cm) thick polyethylene cover sheet is particularly suitable. The support and cover sheet described above provide good protection for the photopolymerizable resist layer. The photocurable layer is prepared from a polymeric component (binder), a monomeric component, an initiator and an inhibitor. Suitable binders which can be used as single binders or in combination with others include polyacrylates and α-alkyl polyacrylate esters such as polymethyl methacrylate and polyethyl methacrylate, polyvinyl esters. For example polyvinyl acetate, polyvinyl acetate/acrylate, polyvinyl acetate/methacrylate and hydrolyzed polyvinyl acetate, ethylene/vinyl acetate copolymers, polystyrene polymers and copolymers with e.g. maleic anhydride and esters, vinylidene chloride copolymers,
For example, vinylidene chloride/acrylonitrile,
Vinylidene chloride/methacrylate and vinylidene chloride/vinyl acetate copolymers, polyvinyl chloride and copolymers such as polyvinyl chloride/acetate, saturated and unsaturated polyurethanes, synthetic rubbers such as butadiene/acrylonitrile, acrylonitrile/butadiene/styrene, methacrylate/acrylonitrile/ Butadiene/styrene copolymer, 2-chlorobutadiene-1,3-polymer, chlorinated rubber and styrene/
Butadiene/styrene, styrene/isoprene/
Styrene block copolymers, high molecular weight polyethylene oxides of polyglycols having an average molecular weight of about 4,000 to 1,000,000, epoxides such as epoxides containing acrylate or methacrylate groups, copolyesters such as those of the formula HO(CH ₂ ) _o OH, where _o is 2 (1) hexahydroterephthalic acid, sebacic acid and terephthalic acid, (2) terephthalic acid, isophthalic acid and sebacic acid, (3) terephthalic acid and sebacic acid, (4) and (5) from the reaction products of said glycols with (i) terephthalic acid, isophthalic acid and sebacic acid, and (ii) terephthalic acid, isophthalic acid, sebacic acid and adipic acid. Copolyester mixtures prepared from nylons or polyamides such as N-methoxymethylpolyhexamethyleneadipamide, cellulose esters such as cellulose acetate, cellulose acetate succinate, cellulose acetate butyrate, cellulose ethers such as methylcellulose, ethylcellulose, and benzylcellulose , polycarbonate, polyvinyl acetal, such as polyvinyl butyral, polyvinyl formal, polyformaldehyde. Preferably, the binder should contain sufficient acid or other groups to render the composition processable in the aqueous developer described above. Useful aqueous processable binders include U.S. Pat.
3458311 and British Patent No. 1507704. Useful amphoteric polymers include U.S. Pat.
Mention may be made of copolymers derived from N-alkylacrylamides or methacrylamides, acidic film-forming comonomers and alkyl or hydroxyalkyl acrylates, as disclosed in US Pat. No. 3,927,199. Preferably, this photosensitive layer is harder than those commonly available heretofore. The greater the hardness of the layer, the greater the dimensional stability and therefore the less need for support by a carrier film. Suitable monomers which may be used as single monomers or in combination with others include: tertiary butyl acrylate, 1,5-pentanediol diacrylate, N,N-diethylaminoethyl acrylate, ethylene. Glycol diacrylate, 1,4-butanediol diacrylate, diethylene glycol diacrylate, hexamethylene glycol diacrylate, 1,3
-Propanediol diacrylate, decamethylene glycol diacrylate, decamethylene glycol dimethacrylate, 1,4-cyclohexanediol diacrylate, 2,2-dimethylolpropane diacrylate, glycerol diacrylate, tripropylene glycol diacrylate, glycerol triacrylate , trimethylolpropane triacrylate, pentaerythritol triacrylate, polyoxyethylated trimethylolpropane triacrylate and trimethacrylate and compounds similar to those disclosed in U.S. Pat. enyl) propane diacrylate, pentaerythritol tetraacrylate, 2,2-di(p-hydroxyphenyl)propane dimethacrylate, triethylene glycol diacrylate, polyoxyethyl-2,2-di-(p-hydroxyphenyl) -Propane dimethacrylate, di-(3-methacryloxy-2-hydroxypropyl) ether of bisphenol A, di-(2-methacryloxyethyl) ether of bisphenol A, di-
(3-acryloxy-2-hydroxypropyl)
Ether, di-(2-acryloxyethyl) ether of bisphenol A, di-(3-methacryloxy-2-
hydroxypropyl) ether, di-(2-methacryloxyethyl) ether of tetrachlorobisphenol-A, di-(3-methacryloxy-2-hydroxypropyl) ether of tetrabromobisphenol-A, tetrabromobisphenol A di-(2-methacryloxyethyl)
Ether, di-(3-
methacryloxy-2-hydroxypropyl) ether, diphenolic acid di-(3-methacryloxy-2-hydroxypropyl) ether, triethylene glycol dimethacrylate, polyoxypropyltrimethylolpropane triacrylate (462), ethylene glycol dimethacrylate , butylene glycol dimethacrylate,
1,3-propanediol dimethacrylate,
1,2,4-butanetriol trimethacrylate, 2,2,4-trimethyl-1,3-pentanediol dimethacrylate, pentaneerythritol trimethacrylate, 1-phenylethylene-1,2-dimethacrylate, pentaerythritol tetramethacrylate , trimethylolpropane trimethacrylate, 1,5-pentanediol dimethacrylate, diallyl fumarate, styrene, 1,4-benzenediol dimethacrylate, 1,4-diisopropenylbenzene and 1,3,5-triisopropenylbenzene can be given. In addition to the ethylenically unsaturated monomers mentioned above, the photocurable layer may also contain at least one of the following free radical initiated chain extending addition polymerizable ethylenically unsaturated compounds having a molecular weight of at least 300: . Preferred monomers of this type are alkylene or polyalkylene glycol diacrylates prepared from alkylene glycols containing 2 to 15 carbon atoms or polyalkylene ether glycols having 1 to 10 ether linkages and US Pat. No. 2,927,022 For example, those having a plurality of addition-polymerizable ethylenic bonds, especially when present as terminal bonds. Particularly preferred are those in which at least one and preferably most of such bonds are conjugated to double bonded carbons, including carbon-carbon and carbon-heteroatoms such as nitrogen, oxygen and sulfur double bonds. be.
Notable examples include materials in which ethylenically unsaturated groups, especially vinylidene groups, are conjugated with ester or amide structures. Preferred free radical-forming addition initiators which are activatable by actinic radiation and thermally inert at 185° C. and below include substituted compounds having two ring carbon atoms in a conjugated carbocyclic ring system. or unsubstituted polynuclear quinones, such as 9,10-anthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, octamethylanthraquinone, 1,4-naphthoquinone , 9,10-phenanthrenequinone, 1,2-benzanthraquinone,
2,3-benzanthraquinone, 2-methyl-
1,4-naphthoquinone, 2,3-dichloronaphthraquinone, 1,4-dimethylanthraquinone,
2,3-dimethylanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, anthraquinone α-sulfonic acid sodium salt, 3-chloro-2-methylanthraquinone,
Mention may be made of retenquinone, 7,8,9,10-tetrahydronaphthacenequinone and 1,2,3,4-tetrahydrobenz(a)anthracene-7,12-dione. Other photoinitiators, some of which are thermally activatable at temperatures as low as 85° C., which are also useful, are described in U.S. Pat. No. 2,760,863, and these include vicinal (Adjacent) Ketoaldonyl alcohols such as benzoin, pivaloin, acyloin ethers such as benzoin methyl and ethyl ether, α-
Mention may be made of α-hydrocarbon substituted aromatic acyloins, including methylbenzoin, α-allylbenzoin and α-phenylbenzoin. US Patent No.
2850445, 2875047, 3097096, 3074974, 3097097 and 3145104
Photoreducible dyes and reducing agents and dyes of the phenazine, oxazine and quinone groups, Michler's ketones, benzophenones, 2,4,5-triphenylimidazolyl dimers with hydrogen donors, and U.S. Pat. Mixtures thereof as described in Patent Nos. 3427161, 3479185 and 3549367 can be used as initiators. The sensitizers disclosed in US Pat. No. 4,162,162 are also useful with respect to photoinitiators and photoinhibitors. Thermal polymerization inhibitors that can be used in the photopolymerizable composition include p-methoxyphenol, hydroquinone and alkyl- and aryl-substituted hydroquinones and quinones, tertiary-butylcatechol, pyrogallol,
Copper resinates, naphthylamine, β-naphthol, cuprous chloride, 2,6-ditertiary-butyl-p-cresol, phenothiazine, pyridine, nitrobenzene and dinitrobenzene, p-torquinone and chloranil. Also useful for thermal polymerization inhibitors are the nitroso compositions disclosed in US Pat. No. 4,168,982. Various dyes and pigments can be added to increase the visibility of the resist image. However, all colorants used should preferably be transparent to the actinic radiation used. B. Substrate Element In general, suitable substrates for the methods of the invention, including printed circuit manufacturing, are those that have mechanical strength, chemical resistance and good dielectric properties. That is, most circuit board materials for printed circuit boards are thermosets or thermoplastics, usually in combination with reinforcing agents. Thermoset resins containing reinforcing fillers are typically used for rigid boards, while thermoplastic resins without added reinforcing agents are typically used for flexible circuit boards. Ceramics and metal coated dielectrics are also useful. Typical circuit board constructions include materials such as phenolic or epoxy resins on paper or paper-glass composites and polyester, epoxy, polyimide, polytetrafluoroethylene or polystyrene on glass. In most cases,
The circuit board is coated with a thin layer of electrically conductive metal, of which copper is very common. Suitable substrates for the method of the invention, including the manufacture of lithographic printing plates, have a mechanical strength and a surface that differs in hydrophilicity or lipophilicity from the surface of the imaging light-sensitive area to which it is laminated. It has the following. Such substrates are disclosed in US Pat. No. 4,072,528. Although a number of substrates are satisfactory for this purpose, the thin anodized aluminum plates disclosed in, for example, US Pat. No. 3,458,311 are particularly useful. As mentioned above, the adhesion A ₂ of the unexposed light-sensitive layer to the substrate, such as copper or aluminum, must be greater than its breaking strength B and its adhesion A ₁ to the support. High values for A ₂ are also required for many applications of the invention where the photosensitive layer must remain adhered to the substrate during exposure to harsh chemical or mechanical conditions. The fact that the printed circuit substrate used in the method of the invention is clean and free of any extraneous substances is essential to ensure that these substances do not interfere with wetting and bonding of the surfaces. be. For this reason, it is often required in the printed circuit board manufacturing field to clean printed circuit substrates prior to lamination by one or more of several cleaning methods well known in the art. The specific method of cleaning depends on the type of contamination: organic, particulate, or metallic. Such methods include degreasing with solvents and solvent emulsions, mechanical scrubbing, alkaline soaking, acidification, etc., followed by rinsing and drying. The appropriate degree of cleanliness is most easily determined by a homogeneous water film test in which the substrate is immersed in water, removed from the water, and then the circuit board surface is observed. If a uniform water film is observed, the circuit board is sufficiently cleaned; however, if a discontinuous striped film or large droplets form, the circuit board is not cleaned properly. It is not sufficiently clean for use in the process. C. Pre-lamination of the Substrate In the method of the present invention, a thermoplastic layer is laminated to the substrate using Nipprole. For most applications, and especially in the manufacture of printed circuit boards from conventional photoresist elements, there is no occlusion or other phase discontinuity, e.g. It is necessary to laminate the plate with a photosensitive layer of the element. Cleaned surfaces tend to deteriorate quickly after cleaning, for example due to oxidation or dust. Accordingly, a preferred embodiment of the invention comprises (a) applying a thin layer of an inert liquid to the surface of the substrate immediately before lamination of the photosensitive layer to the substrate, and (b) evaporating and/or applying a thin layer of inert liquid to the substrate. The substrate surface is treated immediately prior to lamination by a series of steps of removing a thin layer of this liquid from the substrate surface by adsorption to improve the adhesion between the photosensitive layer and the substrate. . No. 153,638, filed May 27, 1980, the inert liquid is a non-solvent for the thermoplastic layer. In a related process disclosed in U.S. patent application Ser. applied to the surface of the substrate by. The inert liquid used in film formation may also be applied in other ways such as by brushing, wicking, spraying or by rolling it using perforated or perforated rolls. be able to. This thin liquid layer should cover at least 30%, and preferably at least 80%, of the surface of the substrate to which the polymer is to be deposited. Even more preferred is essentially complete coverage. Since the invention is preferably integrated into a continuous process in which the support film is removed immediately after lamination, the liquid layer should be thin enough to cause almost instantaneous adhesion to the substrate. be. That is, this liquid should not be applied in large quantities to the substrate surface as described in US Pat. No. 4,069,076. Excess liquid inhibits instant adhesion and also fills interconnect pores normally present in printed circuit substrates, thereby acting as a contaminant in subsequent processing operations. In practice, it is preferred that this thin liquid layer be as thin as practical to displace interfacial air and promote adhesion of the photosensitive layer. Although the specific layer thickness will vary somewhat depending on the nature of the liquid and the application conditions, it is generally preferred that it be much thinner than in prior art methods, e.g. 1-50 microns. The average layer thickness is about 30 microns, or a preferred range of about 10 to about 50 microns. It is an essential aspect of this substrate treatment that during the subsequent lamination operation, the applied thin liquid film is substantially removed from the interface between the photosensitive layer and the substrate. This is primarily done by diffusion into the laminated polymer layers. The exact manner in which the thin liquid film layer is removed is, of course, a function of the liquid used and the nature of the photosensitive layer and substrate. If more volatile liquids are used in combination with heated lamination rolls, liquid film displacement may be accomplished in part by evaporation. On the other hand, the use of less volatile liquids and/or cooler rolls results in less evaporation, ie, removal of the liquid film occurs mostly by absorption into the laminated polymer layers. If clearly non-volatile liquids are used, removal of the liquid film is essentially by absorption. The exact mechanism by which the liquid film is removed is not critical. Even relatively hard thermoplastic layers can be efficiently adhered to substrates using the thin film process described above. Of course, the substrate must be clean. Integration of the cleaning operation with the lamination operation provides the required degree of cleanliness. Without the presence of this film during lamination, this layer will not adhere instantaneously to the substrate. Preferably, the precleaning operation is carried out in an integrated manner as described in US Patent Application No. 153,636. D. Trimming Longitudinal tensile stress A single application serves to simultaneously trim layers from both the trailing edge of the preceding board and the leading edge of the succeeding board. On the other hand,
If successive plates are spaced in such a manner that there is a "bridge" of light-sensitive layer extending into the gap between the trailing edge of the preceding plate and the leading edge of the succeeding plate, It is necessary to trim the two edges separately. In this case, a tensile stress is applied to trim the leading edge of the plate. This is done by removing the support film from the ply by bending the film backwards at an obtuse angle along the longitudinal axis of the advancing ply as the laminated substrate element emerges from the nip of the laminating roll. It is preferable to do so. The radius of this bend is small enough to exceed the breaking strength of the layer on the leading edge of the substrate element. The invention will be more clearly understood by reference to the following examples and the detailed description of the drawings below. Example 1 Resist Properties A roll of photoresist film without a cover sheet is prepared as follows. A photosensitive coating solution is prepared with the following composition:

【table】

[Table] 85% have a diameter of less than 10μ and 15%
13 parts by weight of polyethylene beads having a diameter of 10-20μ are dispersed in the coating solution. This mixture is coated onto a 0.00127 cm thick polyethylene terephthalate web, which has a thin layer of a mixture of carnauba wax and poly(vinylidene chloride) coated on its back side. The photopolymerizable layer is dried to produce a dry thickness of 0.00254 cm, and the dried coated element is approximately
Roll up 30.5m into a roll. Referring to FIG. 1, each member of a series of substrate elements (boards) for a printed circuit board 1 is mechanically cleaned of both its copper-clad upper and lower surfaces by scrubbing under a strong water spray. It is mechanically advanced in a continuous manner on a roller conveyor through the cleaning chamber 3 to be cleaned. This board is manufactured from fiberglass reinforced epoxy resin. The cleaned substrate plate, as defined by the homogeneous water film test, is further advanced through an alignment roll 5, thereby accurately aligning the sides of the plate. Each aligned substrate plate comes out from this alignment roll 5. This is then fed between the liquid application rolls 6, where a thin layer liquid (in this case a 30% ethanol/water solution) is fed inside the hollow application rolls 6 via line 7. Preferably, this application roll 6 is perforated in a regular pattern having thereon a rigid porous polyethylene sleeve covered with a cotton fabric through which the thin liquid passes and through which a thin layer of liquid is coated onto the substrate plate. Consists of a metal core. The liquid level in the application roll 6 is limited by a fixed level discharge line 8. The liquid layer has a thickness of 10-50μ. The plate, which has both surfaces coated with a thin layer of liquid, is then advanced to a set of upper and lower feed rolls 9, each of which covers the unprotected surface of the continuous supported photosensitive layer 11 of the substrate element. It is positioned facing a thin layer of liquid. The optional supply roll 9 is supplied with the photosensitive layer against the surface of the substrate element without the application of pressure, just before the layer and substrate are fed into the nip of the lamination roll. Excess liquid is removed from the substrate surface in droplets at the nip as the element passes between supply rolls 9. By this method, moisture is retained between the layer and the substrate and thermal exposure is limited to a short period of time while it is in the nip. In the case of termination, the amount of photosensitive layer exposed to thermal decomposition is substantially reduced. The supply roll 9 is arranged in such a manner that as the circuit boards enter the supply roll 9, they abut each other and there is no significant amount of bridging by the film between the trailing and leading edges of each board. mechanically connected to the mechanism used for the advancement of the plate 1 at. A photosensitive layer with a support prepared as described in the examples is supplied from a supply roll 12.
The abutted plates 1 with the photosensitive layer 11 with the support in place are then advanced through the nip of heated lamination rolls 13 where the photosensitive layer 11 is subjected to both heat and pressure;
A thin liquid layer is thereby removed from the substrate by absorption into the photosensitive layer. The temperature of the laminate roll surface is about 230° and the linear speed of the circuit board through the laminate is about 6 feet per minute. Lamination is completed within about 40 seconds after cleaning the board. The laminates 1, which are still abutted against each other, are advanced between the wedges 15 at a uniform speed. At the exit of the wedge 15, the poly(ethylene terephthalate) web 1 on the outer surface of the continuous film
7 is pulled uniformly backwards at an obtuse angle (here 150°), thereby trimming the photosensitive layer in a straight line along the leading edge of the plate 1. The web 17 is pulled rearward by the action of the take-up rolls 19 and by the advancing action of the plate. A mandrel slip clutch mechanism is preferably used to maintain proper tension on the take-up roll. As the substrate plate 1 emerges from the wedge 15, progressively more of the photosensitive layer is stripped off, and finally the plate is passed through a set of clutch-actuated trimming rolls 2.
1, and during which it is firmly caught on the side. The trimming rolls 21 are rotating at a speed greater than the linear speed of the advancing plate until they capture the sides of the panel. The trimming roll is then moved at the linear velocity of the plate by means of a slip clutch which compensates for the difference in operating speed. The trimming roll 21 exerts a tensile stress on the layer which causes it to trim the thermoplastic layer smoothly along the rear edge of the board as it emerges from between the wedges 15. Once the trailing edge trimming is complete and the series leading and trailing boards are separated, the laminate is ready for circuit board manufacture by conventional photoresist techniques. FIG. 2 is a schematic diagram in cross-section of a preferred method of carrying out the lamination step of the present invention, in which, after layering of a thin liquid film 100, a photosensitive layer 102 adhered to a support film 104 is laminated. A thin layer of copper 107 is laminated to the coated substrate 106 by passing through rolls 108 and 110. Copper coating of substrate 107
The adhesion strength A ₂ between the photosensitive layer 102 and the support 104 is the adhesion strength between the photosensitive layer 102 and the support 104.
A is greater than ₁ . FIG. 3 is a schematic diagram in cross-section of a preferred method for trimming the leading edge of the laminated substrate 106 when spaced apart in a series of advancing substrates. Once emerging from the lamination rolls, the support 104 and the photosensitive layer 102 are pulled backwards on the wedge 112 at an obtuse angle and with a small radius so that the breaking strength B of the photosensitive layer 102 at the leading edge of the substrate 106 is 3B. Layer 1 across the leading edge of substrate 106 as shown.
Make it bigger than cause the destruction of 02. For this operation, A ₁ is greater than A ₂ and
And A ₂ is greater than B. FIG. 4 is a schematic diagram in cross-section of a method for trimming the trailing edge of a stacked substrate 106 in a spaced series of advancing substrates. When the support is removed from the trailing edge of the substrate 106, longitudinal tensile stresses perpendicular to the trailing edge, parallel to and in the direction of travel, pull the leading edge of the substrate, thereby reducing the light sensitivity along the trailing edge. This is applied by making the breaking strength B greater than the breaking strength B of the layer 102. Although, as described above, the method of the present invention is carried out continuously, it will be appreciated that the method can also be carried out intermittently. Preferably, the thermoplastic layer to be used in this method is relatively harder than most photosensitive layers. This hardness of the layer makes it relatively brittle. That is, under high shear, the layer clearly loses its strength due to a decrease in viscosity, so that the layer exhibits dilatent properties. This method has the advantage that when the layers are placed in tension after lamination, the layers are cut along the rear edge of the substrate and do not simply stretch or fracture randomly, as is the case with softer layers. is taking advantage of this advantage. In a preferred embodiment, the method is carried out simultaneously on both sides of a series of substrates, so that the photopolymerizable layer is deposited on both sides of the substrates. in this case,
It is particularly important that no liquid is present in the pores of the matrix. Otherwise, the heat of the lamination will vaporize the liquid and cause the "tent" of the photosensitive layer above the pores of the substrate to expand or rupture. Also, the series of substrates are close enough together that the spring-loaded lamination rolls normally used for lamination will "sink" between the substrates.
It is preferable not to do so. This prevents two photopolymerizable layers extending between successive substrates from bonding together, ie, "hinging" between successive substrates. The reason is that such a bond would probably inhibit self-trimming of the leading edge when removing the support film. Alternatively, the pressure on the lamination rolls can be reduced to minimize bonding of the layers. However, it is preferred to keep "hinging" itself to a minimum to facilitate self-trimming functionality. EXAMPLE Manufacture of a lithographic plate A light-sensitive coating mixture is prepared and coated as in the example, but here instead of the beads used therein, polyethylene beads of 1 μ size (“Micro-Fine-F
16 parts by weight of "Gold", a product of Doura Commodities Corporation) were dispersed in the coating solution. The surface of a 0.023 cm thick aluminum plate was scrubbed in water using a ``Chemcut'' Model 107 (Chemcut Corporation product) mechanical cleaning system with a tungsten carbide brush, and this rubbed surface was cleaned as described in the example. The photosensitive layer was laminated to the photosensitive layer and this layer was trimmed. The laminated and trimmed plates were imaged by exposing the photosensitive layer for 60 seconds to ultraviolet radiation from a 2000 Watt pulsed xenon arc in a flip top plate marker through halftone and line transparencies. The unexposed areas were completely removed by developing in a 1% aqueous solution of sodium carbonate to give a halftone polymer image with complementary image areas of the bare aluminum surface. The resulting lithographic plates were gummed in the usual manner with "Leidel" finishing solution (LDFS) (a product of Dupont) and
It was mounted on an AB Dick Model 380 offset printing press. At least 3500 good quality copies were obtained from this printing plate using standard inks and fountain solution.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating a preferred application of the method of the invention in a continuous lamination process. FIG. 2 is a schematic diagram in cross-section of a preferred substrate treatment scheme prior to lamination of the photosensitive layer. Figure 3 A and B
1 is a schematic diagram illustrating in cross-section a preferred method for trimming a photosensitive layer from the leading edge of a substrate laminated by this method; FIG. and FIG. 4 is a diagram illustrating in cross-section a preferred method for trimming the photosensitive layer from the rear edge of a substrate laminated according to the method of the present invention.

Claims (1)

Claims: 1. A series of steps: (1) advancing a continuous layer of a light-sensitive organic polymer composition supported on only one side by a releasable polymeric film; (2) bringing the unsupported side of the supported layer into contact with the surface of the substrate element under pressure within the nip; (3) optionally removing the support film from the layer as the laminated substrate element emerges from the nip of the lamination roll; (4) continuing the advancement of the laminated substrate element until it is completely removed from the layer; (4) at the rear edge of the substrate transversely to the direction of advancement;
(5) tensioning the stacked matrix elements in a direction of travel along their longitudinal axes until the breaking strength of the stacked layers and their support film, if present, is exceeded; and (5) the series of subsequent matrix elements. laminating successive layers of a photosensitive composition on the surface of each member of a series of substrate elements including repeating the series of steps (2) to (4) above regarding An integrated method for trimming this layer from at least one of the edges. 2. The photosensitive composition has non-fibrous solid particles randomly dispersed therein having a particle size of 0.1 to 25 microns, and the layer has an optical density of about 0.7 or less and a breaking point of about 2 to 50%. 2. A method according to claim 1, comprising elongation. 3. The surface of the layer with a support without a support and the surface of the substrate element to be laminated are
The method according to claim 1, wherein the contact is made without applying pressure immediately before (2). 4. The method according to claim 1, wherein both surfaces of the substrate element are laminated simultaneously. 5. The method of claim 1, wherein the carrier film is removed by the action of a driven take-up roll. 6 The tensile action on the stacked substrate elements grips the elements in step (4) with frictional contact between the sides of the elements and a set of drive rolls rotating on axes perpendicular to the plane of the advancing substrate elements. 2. A method according to claim 1, wherein the method is carried out by advancing. 7. The following sequence of steps: (1) advancing a continuous layer of a photosensitive organic polymer composition supported on only one side by a releasable polymeric film and spaced apart from this supported continuous layer; (2) bringing the unsupported side of the supported layer into contact with the surface of the substrate element under pressure within the nip; (3) laminating the ply to the surface of the substrate element; (3) on the longitudinal axis of the ply proceeding with a bending radius sufficient to exceed the breaking strength of the ply as the laminated substrate element emerges from the nip of the laminating roll; (4) trimming the leading edge of each element by bending the support film backwards along the trailing edge of the substrate in a direction transverse to the direction of travel;
(5) stretching the stacked substrate elements in the direction of travel along their longitudinal axes until the breaking strength of the stacked layers is exceeded; repeating a series of steps comprising laminating successive layers of a photosensitive composition onto the surface of each member of the series of substrate elements, and applying this layer from at least one of the lateral edges of the laminated substrate elements. Integrated method for trimming. 8. The photosensitive composition has non-fibrous solid particles randomly dispersed therein having a particle size of 0.1 to 25 microns, and the layer has an optical density of about 0.7 or less and a breaking point of about 2 to 50%. 8. A method according to claim 7, comprising elongation. 9 The unsupported surface of the layer with a support and the surface of the substrate element to be laminated are
The method according to claim 7, wherein the contact is made without applying pressure immediately before (2). 10. The method of claim 7, wherein both surfaces of the substrate element are laminated simultaneously. 11. The method of claim 7, wherein the carrier film is removed by the action of a driven take-up roll. 12 The tensile action on the stacked substrate elements grips the elements in step (4) with frictional contact between the sides of the elements and a set of drive rolls rotating on axes perpendicular to the plane of the advancing substrate elements. 8. A method according to claim 7, wherein the method is carried out by advancing.