CN1958665A - Dielectric composition for use in circuitized substrates and circuitized substrate including same - Google Patents

Abstract

A dielectric composition which is adapted for combining with a supporting material (e.g., fiber-glass cloth) to form a dielectric layer usable in circuitized substrates such as PCBs, chip carriers and the like. As such a layer, it includes a resin, a predetermined percentage by weight of a filler, and, significantly, only a minor amount of bromine. A circuitized substrate comprised of one or more of these dielectric layers and one or more conductive layers is also provided.

Description

The dielectric combination and the circuitized substrate that comprises it that are used for circuitized substrate

The cross reference of common application case co-pending

The S.N.10/812 that is entitled as " Circuitized Substrate; Method Of Making Same; Electrical Assembly Utilizing Same; And Information Handling System Utilizing Same " that submits on March 31st, 2004,890 (inventors: people such as R.Japp), defined circuitized substrate, electrical assembly and information processing system, it can utilize the dielectric layer that uses dielectric combination taught herein to make.In this common application case co-pending, also defined the method for making described substrate.

At the S.N.10/812 that is entitled as " Dielectric Composition For Forming DielectricLayer For Use In Circuitized Substrates " that submits March 31 in 2004 equally, 889 (inventors: people such as R.Japp), defined the dielectric combination that forms the dielectric layer in the circuitized substrate that can be used for for example PCB, chip carrier and analogue.As this type of layer, it comprises the particulate filler (particulate filler) of curing resin material and predetermined weight percent, does not therefore comprise that continuous fibre, semicontinuous fiber or analogue are as its part.

The application's case is S.N.10/812,889 the part application case that continues.

The S.N.10/920 that is entitled as " Low Moisture Absorptive Circuitized Substrate; Method Of Making Same; Electrical Assembly Utilizing Same; And Information HandlingSystem Utilizing Same " that submits on August 18th, 2004,235 (inventors: people such as I.Memis), defined a kind of circuitized substrate that comprises the first layer, described the first layer is made up of dielectric materials, described dielectric materials comprises that the gained dielectric layer that is combined to form does not thus comprise that continuous or semicontinuous fiber is as its part in conjunction with the low water absorbable polymer resin that is wrapped in the tubercle fluoropolymer net in the resin.Described substrate further comprises at least one the circuit layer that is positioned on the described dielectric the first layer.A kind of electrical assembly and a kind of method of making described substrate also are provided, and as information processing system (for example, computer), it comprises that circuitized substrate of the present invention is as its part.

The S.N.11/086 that is entitled as " Low Moisture Absorptive Circuitized Substrate; Method Of Making Same; Electrical Assembly Utilizing Same; And Information HandlingSystem Utilizing Same " that submits on March 23rd, 2005,323 (inventors: people such as I.Memis), defined a kind of circuitized substrate that comprises composite bed, described composite bed comprises: the first dielectric sublayer, and it comprises the plural number kind fiber with low thermal coefficient of expansion; With the second dielectric sublayer with low water absorbable resin, the described second dielectric sublayer does not comprise that continuous or semicontinuous fiber or analogue are as its part.Substrate comprises that further at least one conductive layer is as its part.A kind of electrical assembly and a kind of method of making described substrate also are provided, and as information processing system (for example, computer), it comprises that circuitized substrate of the present invention is as its part.

All above-mentioned application cases all transfer the transferee identical with the application's case.

Technical field

The present invention relates to be used for the dielectric combination of circuitized substrate, for example those are used for the circuitized substrate of printed circuit board (PCB) (hereinafter also being called PCB), chip carrier and analogue to described circuitized substrate, and more particularly, the present invention relates to such composition, when it makes up in the supporting structure with for example glasscloth, be used to form dielectric layer, described dielectric layer can be used as the part of this type of substrate, for example as the electric insulation layer between the conductive layer (for example forming signal, power supply and the ground plane of the part of final structure).More particularly, the present invention relates to guarantee that this series products can comprise the composition of high-density circuit in this type of conductive layer.

Background technology

The circuitized substrate of used printed circuit board (PCB), layering chip carrier and analogue must allow to form a plurality of circuit in for example current a lot of technology in the volume of minimum or space.Indicated as mentioned, these the finished product comprise " piling up " of the layer of signal, ground connection and/or the voltage plane (line) that are separated each other by at least one dielectric materials layer usually.Circuitry lines or pad (for example those circuitry lines or the pad of signal face) form each other by the electroplating hole that passes dielectric layer usually and electrically contact.If electroplating hole is positioned at inside, be commonly referred to " hole " so,, be commonly referred to " blind hole " so if begin in described plate, to extend predetermined depth from outside surface, if or fully extend through the whole thickness of plate, be commonly referred to " electroplating ventilating hole " (hereinafter also abbreviating PTH as) so.Adopt as used herein term " through hole " to be intended to represent to comprise all these type of plate openings of three types.

Past, in the past few years the complicacy of products obtained therefrom as described herein significantly increased.For instance, the PCB that is used for giant-powered computer can have nearly 36 layers of circuit or more, and the whole thickness that has up to about 0.250 inch (250 mil) that piles up.The common through hole that these plates are designed to have wide signal wire of 3 or 5 mils and 12 mil diameter.The circuit densification that increases in of today a lot of products for for example PCB, chip carrier and analogue, industry are wished signal wire is reduced to the width of 2 mils or littler and through-hole diameter is reduced to 2 mils or littler.The commercial program of knowing most (those programs that especially have character as herein described) can not form industrial desired size economically.The already known processes that is used to make PCB, chip carrier and analogue comprises usually makes independently internal layer circuit (circuit layer), forms described internal layer circuit by sensitive layer or film are coated on the copper layer that covers copper inner substrate material.Make light sensitive layer imaging, development, and the copper of etch exposed is to form lead.After etching, peel off photosensory membrane from copper, circuit pattern is stayed on the surface of inner substrate material.This technology also is called photoetching process and thinks it unnecessary and will be further described in the PCB technology.

After forming indivedual internal layer circuits, the stacked multiple-level stack that forms by preparation internal layer, ground plane, voltage plane or the like, described internal layer, ground plane, voltage plane or the like separate each other by a dielectric preimpregnation material (dielectric pre-preg) usually, and described dielectric preimpregnation material comprises glass (the being generally glass fibre) cloth that one deck is impregnated with partly solidified material (being generally B rank Resins, epoxy) usually.Top of piling up and bottom exterior layer comprise usually covers copper, that fill through glass, Resins, epoxy planar substrate, and wherein said copper coating comprises the outside surface that piles up.Come with completely solidified B b stage resin b by heating and pressurization that lamination is described to be piled up to form single chip architecture.Piling up of forming like this has metal (being generally copper) coating usually on two outside surface.In described copper coating, form the external circuit layer by using with the similar program of program that is used to form internal layer circuit.Photosensory membrane is applied to the copper coating.Make coating be exposed to patterning activating radiation and development.Then, use etching reagent to remove the copper exposed by the development of photosensory membrane.At last, remove remaining photosensory membrane so that the external circuit layer to be provided.

Conductive through hole (also being called interconnection usually) is generally used for the individual circuits layer in the structure being electrically connected to each other and being connected to outside surface, and passes described all parts or a part of piling up usually.Usually form on the outer surface before the circuit, describedly pile up boring and form through hole by passing in position.After several pre-treatment step, the wall in described hole, and is metallized by contacting with no electricity or electrolytic copper electroplating solution by catalysis usually by contacting with plating catalyst, so that form conductive channel between circuit layer.After forming conductive through hole, form external circuit or skin by using program mentioned above.

After construction, chip and/or other electric assembly are installed in the appropriate position on the external circuit layer of multiple-level stack, use the welded and installed pad to join described assembly to PCB usually.As required, described assembly forms by the circuit in conductive through hole and the structure usually and electrically contacts.Usually, form described welded gasket by applying organic solder mask coating on the circuit layer outside.Can have opening by use is coated in liquid solder mask coating material silk screen with the silk screen that defines desire and form the zone of welded and installed pad on the surface of external circuit layer and applies solder mask.Perhaps, but light imaging solder mask can be coated on the plate and exposure and developing with the array of the opening that obtains defining weld pad.Then, by using known in the industry method (for example wave soldering) the described opening of solder-coated.

Develop ever-increasing high speed circuit substrate and caused exploring new material with the necessity that is used in a lot of product innovation of today (for example, computer), it will reach the electricity and the thermal property limitations of present available technology.For high-speed applications, be necessary to make extremely fine and close conductor circuit to be patterned on the low dielectric constant insulating material.The preimpregnation material laminate that is used for the custom circuit plate is made by the substrate reinforced glass fabric that is impregnated with resin traditionally, and described substrate reinforced glass fabric is at industrial " FR4 " dielectric materials that also is called by some, and FR represents fire retardant and 4 its correlations of expression.Resins, epoxy/glass laminates the product that is used for some present products contains the glass fibre of the 40 weight % that have an appointment and the Resins, epoxy of 60 weight % usually, and has relative higher dielectric constant (Er) usually, is higher than 4.0 sometimes.This type of higher relatively Er causes the electricimpulse (signal) in the adjacent signal circuitry lines to be propagated more lentamente again, causes too much signal delay time.Along with novel more computer system becomes faster, the systemic circulation time must become shorter.By signal at PCB be used for the expert and then highly significant that will become time of lag that cause of other circuitized substrate of this series products; Therefore need low Er laminating material.Expect that a lot of products all need 2.8 or lower total Er.Do not having under the situation of novel material, can not obtain described low Er, because the Er of indicated as mentioned conventional FR4 Resins, epoxy and common glass fibre is usually in the scope of 4-6.Effective Er of this type of matrix material can be estimated by the simple weighted average value of its volume fraction that is contained in the Er of each indivedual composition and the described mixture usually.As hereinafter further explaination, also become to assign to bromination usually, to guarantee desired FR grade than important place weighting above-mentioned composition.

As known, for example the Er of " pure " fluoropolymer of polytetrafluoroethylene (PTFE) is about 2.0.Yet,, in construction board layer rolled-up stock, use this type of material to be proved to be impracticable sometimes separately because this material has relatively poor mechanical characteristics and chemically inert cause usually.A kind of substitute is with a kind of as in the composition of composite laminates of fluoropolymer, for example strengthens the fiber in the cloth.The example is by Newark, the treated PTFE fabric preimpregnation material that the W.L. Gore and Associates of Del makes.When such fabric was used for replacing the glass fibre of conventional Resins, epoxy/glass laminates product, Er dropped to 2.8.Yet, use this fabric to have some shortcoming.Because the relatively low modulus of pure PTFE, the thin layer rolled-up stock made from these materials is not unusual inflexible, and need take special care to processing.Equally, when the laminate that comprises the PTFE fabric is holed, do not cut the PTFE fiber and trend towards being projected in the hole of having bored and be difficult to remove.In order to obtain good plating bounding force, must be expensive by in nitrogen atmosphere, using, highly combustible chemical or the PTFE surface of handling exposure by plasma process, described plasma treatment must be permeated via hole with high aspect ratio, so that obtain good plating bounding force.Undoubtedly, one of maximum inferior position of PTFE fabric laminated product is a cost, and the higher cost that causes owing to additional processing request and apparatus modifications is not only arranged, and buys the great amount of cost of prepreg itself in addition.Ideally, the value of Er should be very aerial value near the limit 1.0,1.0.

Another characteristic that influences the performance of lamination dielectric materials is thermal expansivity (CTE).Wish the X of dielectric materials and the thermal expansivity precision-matched of thermal expansivity on the Y direction and adjacent dielectric layer, preventing from PCB is connected to the solder joints open of the device of surface mounting, or avoid copper to separate, or prevent the PCB warpage with dielectric medium.X and Y direction CTE are usually by intramatrical glass fibre control.Yet these fibers are not controlled Z direction CTE.Z direction CTE must be also controlled to prevent that the copper facing through hole from splitting during heating cycle.Be welded to connect in preparation or reprocessing, and in other manufacturing process, and when production board in operation or during the air current flow when shipment or memory period stand temperature variation, generation heat.A kind of method of revising CTE is to use weighting material.Weighting material can be connected to matrix polymer, by using coupler (being generally silane) these weighting materials is added in the matrix polymer.Coupler has improved the keyed jointing between weighting material and the polymkeric substance, has optimized the interface calmodulin binding domain CaM, and this has also improved electrical property and mechanical property.Various types of weighting materials can influence the dissipation loss of mixture.When reaching the flex point that is called glass transition temperature (Tg), the CTE of preimpregnation dielectric materials changes significantly.Because when reaching Tg, the rate of expansion of dielectric materials significantly increases, and has high Tg so that minimise stress so wish dielectric materials.For instance, think that the dielectric materials based on epoxy novolac has higher relatively Tg, be generally 150 degrees centigrade or bigger.Other characteristic relevant with high Tg generally includes low water absorbable and chemical resistant properties.

The United States Patent (USP) of issuing on June 30th, 1,992 5 that is entitled as " Flame Retardant; Low Dielectric ConstantMicrosphere Filled Laminate ", a kind of known materials of attempting to satisfy a lot of requirements in the above-mentioned requirements is described in 126,192.According to the teaching of this patent, microballoon/carrier structure preimpregnation material that preparation is handled through resin/silane makes its B rank curing and follows vacuum lamination.Adding to by the microballoon with predetermined amount is enough to cause when solvent distillates (for example) to be about in the resin/solvent mixture of 50% encapsulation factor to prepare dip compound.Must use low State Shear Compounding to avoid damaging microballoon.Because these are globular, so in case microballoon mixes easily and the viscosity of solution is increased to surpass promptly be difficult to flood a bit.The combination of microballoon size and encapsulation factor makes the dielectric materials of filling can hold out against laminated heat and pressure cycling with concluding, and does not experience the breakage of hollow microsphere.According to this patent, nearly observe under 500 pounds the lamination pressure at (PSI) per square inch and to be less than 2% microballoon breakage.When breakage took place really, maximum microballoon at first broke usually.Contain be less than 2% sodium oxide, wherein diameter less than 40 microns microballoon account for sum 99%, obviously be called Grace Syntactics by name, the company of Inc. is described to acceptable with the hollow silica microballoon that " SDT 28 " title provides.The size of this same company is described to preferred weighting material less than " SDT-60 " microballoon of 99% that 25 microns microballoon accounts for sum.Handle described microballoon with the coupler that is suitable for specific resin uses based on silane.Also mentioned the coupler that is particularly useful for these prescriptions.A kind of coupler mixture is described as the combination of vinyl silanes and aminosilane, to obtain best wet fastness and acceptable wet dielectric loss performance.Silane resin is bonded in the weighting material particulate in the resinous substrates with concluding, and the volume of the interface zone between resinous substrates and the microballoon is minimized.Carrier/reinforcement material in this patent can be any known shell mould stiffener, for example glass or polytetrafluoroethylene (PTFE).Selected support fabric major part depends on the needed characteristic of finished product laminate.These characteristics comprise thickness, Er, CTE and desirable product application.Solid support material comprises braiding and non-braided glass fibre and polymeric fabrics and cushion block.Also can use for example organic membrane of polyimide film.Also can in prescription, use for example aromatic poly, polyparaphenylene benzo double thiazole (poly p-phenylene benzobisthiazole), polyparaphenylene Ben Bing Er oxazole (polyp-phenylene benzobisoxazole), polyether-ether-ketone, aromatic polyester, quartz, S glass and the analogue of low Er fabric, for example Kevlar and the Nomex of D glass (both is the registered trademark of E.I.Dupont de Nemours and Company).Described stiffener can be to mix to be knitted or mixed form.

The United States Patent (USP) of issuing in March 27 calendar year 2001 6 that is entitled as " Laminate And Method Of Manufacture Thereof ", be described as design in 207,595 and wish to satisfy equally the another kind of known materials of the above-mentioned requirements of high speed product of today for example above using in the circuitized substrate of defined substrate.In this patent, the textile material of dielectric layer is made by the cloth composition, described cloth composition has the particle of enough low levelss and capacity resin material to comprise particulate cloth composition fully, making resin material extend beyond the highest projection of cloth composition (anticipates promptly, textile material thicker and will by a certain testing standard (' in 595, known HAST grade A test).Therefore, known woven cloth comprises some particles, in that ' in 595, dry film, excessive coupler, broken filament (broken filament) and uneven surface fragment represented to comprise in this term.Described a kind of technology, wherein before the braided fiber bundle, the sizing material that polyvinyl alcohol, W-Gum and oily lubricant are formed is applied to fibrous bundle, to improve weaving and the fracture of bundle is minimized.After braiding, remove described sizing material by calcination steps, so that remove long filament and other material of lubricant.Yet some sizing materials have stayed as particle randomly.What comprise the particulate woven cloth is some hardened resin materials.Described resin can be Resins, epoxy, for example is generally used for a kind of Resins, epoxy of " FR4 " mixture.Based on the resin material of Bismaleimide Triazine (BT) also for this reason the structure in the patent accept.More preferably, but described resin is a known phenolic aldehyde hardening resin material in the PCB industry.Therefore, this patent needs continuous fibre, and (those continuous fibres are crossed whole width (or length) extension of dielectric layer, but cause possible being not intended to be interrupted by needed through hole in the finished product is holed, thereby cause these fibers to become the fiber that can be described as " fracture ").The foregoing problems that therefore, in the technology of this patent and resulting structures, may have the fibrous bundle that is exposed to the hole.

At United States Patent (USP) 5,418, in 689, the PCB product has been described, wherein dielectric substrate can comprise thermoplasticity and/or thermosetting resin.Mentioned thermoset polymerization material comprises Resins, epoxy, phenols base material, polyimide and polymeric amide in this patent.The example of some phenol aldehyde type materials comprises the multipolymer of phenol, Resorcinol and cresols.The thermoplastic polymeric material's that some are suitable example comprises for example polyacrylic polyolefine, polysulfones, polycarbonate, paracril, abs polymer and fluorocarbon polymer, for example the polymkeric substance of tetrafluoroethylene, trifluorochloroethylene, fluorinated ethylene-propylene polymer (fluorinatedethylenepropylene polymer), polyvinylidene difluoride (PVDF) and polyhexafluoropropylene.Dielectric materials can be the molded articles of the polymkeric substance of the weighting material that contains the polymkeric substance that glass for example fills and/or stiffeners.Used " FR4 " composition epoxy resin contains the bromination polyglycidyl ether of the bisphenol-A of 70-90 part in this patent, with usefulness 3-4 part Dyhard RU 100 solidified 10-30 part four (hydroxyphenyl) ethane four glycidyl ethers, with 0.2-0.4 part tertiary amine, all umbers all are the parts by weight with respect to each hundred parts of resin solid.Another " FR4 " composition epoxy resin can contain the 25 tetrabormated diglycidylethers to the bisphenol-A of about 30 weight parts of having an appointment, and it has about 350 to about 450 Resins, epoxy equivalent weight; The tetrabormated glycidyl ether of about 10 to about 15 weight % bisphenol-A, it has about 600 to about 750 Resins, epoxy equivalent weight and the about 55 non-linear phenolic varnish of at least a epoxidation to about 65 weight parts, and it has at least 6 terminal epoxy groups; Together with suitable curing and/or stiffening agent.Another " FR4 " composition epoxy resin contain 70 to 90 parts bisphenol-A the bromination polyglycidyl ether and with four (hydroxyphenyl) ethane, four glycidyl ethers of 10 to 30 parts of the glyoxal ethyline solidified of 0.8-1phr.Another " FR4 " composition epoxy resin is used as solidifying agent with tetrabromobisphenol-A, together with glyoxal ethyline is used as catalyzer.

At United States Patent (USP) 6, in 323,436, by at first flooding non-braiding chopped aramid fiber cushion block or thermoplastic liquid crystal polymer (LCP) paper, replace the normally used stiffener that in this patent, is described as woven glass fabric in the electronic industry, prepare PCB.(form by the directed cushion block in (in the plane) at random of poly-(poly P phenylene diamine terephthalamide) fiber by the p-aromatic poly for the aromatic poly stiffener, (poly-(poly P phenylene diamine terephthalamide) fiber is formed (registered trademark that Kevlar is E.I.DuPont de Nemours and Company) by Kevlar to described p-aromatic poly, and compare with the specific inductivity 6.1 of standard E-woven fiber glass, described aromatic poly stiffener has specific inductivity 4.0.The more low-k of non-braiding aromatic poly stiffener is propagated for signal faster and is prepared, and allows the wiring density that increases and crosstalking still less, and this becomes more and more important concerning high I/O chip and miniaturization.Because when making up with thermosetting resin, the p-Kevlar is transversely isotropic and has-3 to pact-6ppm/ degree centigrade axial CTE approximately, so the resulting composite described in this patent allegedly has the CTE that arrives in about 10ppm/ degree centigrade the scope about 3, it can be through control and through regulating the CTE with coupling silicon or semi-conductor chip.Thermoplastic liquid crystal polymer paper is the material (Vecrus is the registered trademark of Hoechst Celanese Corp.) that is called Vecrus.LCP paper uses the Vectra polymkeric substance (Vectra also is the registered trademark of Hoechst Celanese Corp.) of described company.According to this patent, it has specific inductivity 3.25 and dissipation factor 0.024 when 60Hz.Polymer paper has the UL94-V0 grade and less than 10ppm/ degree centigrade flat and interior CTE.Through concluding that the advantage that this material is better than the aromatic poly cushion block is lower specific inductivity and low-down water-absorbent, it is less than 0.02%.The linkage heat thermosetting resin uses non-braiding aromatic poly or LCP paper so that form final compound substrate.Comprise Resins, epoxy, cyanate, bismaleimides, bismaleimides-triazine, maleimide or its combination according to the example that is described in thermosetting resin useful in this patent.Then, will partly be cured to " B " rank, and, and then cut, pile up and the described preimpregnation material of lamination, so that form sub-mixture with outer copper sheet so that form the preimpregnation material through the low CTE stiffener of resin impregnation.

The dielectric materials that becomes known for another type in the circuitized substrate comprises those materials that are called " expansion PTFE " material, the name of PTFE yes tetrafluoroethylene.The more common example of this type of material is aforementioned Teflon (Teflon) of being sold by E.I.DuPont deNemours and Company.For instance, at United States Patent (USP) 5,652, in 055, described and be suitable in multiple adhesive application (for example in board layer rolled-up stock, multi-chip module and in other electrical applications) as adhesive sheet (or " binding film ") material of bonding coat.According to description, described adhesive sheet is to come construction by expanded ptfe (PTFE) material, for example as United States Patent (USP) 3,953, and institute's teaching in 566.Preferably, described material is filled with inorganic filling material and following construction.Ceramic weighting material is included in the aqueous dispersion of the PTFE that produces dispersion.The size of weighting material that is the small particle form is usually less than 40 microns, and preferably less than 15 microns.Introducing a certain amount of weighting material before the cohesion altogether, described amount will provide the weighting material of 10 to 60 weight % and preferred 40 to 50 weight % in PTFE, and this mixture with final resin impregnation is relevant.Then, common making through the PTFE dispersion of filling by quick stirring condensed altogether.Then add cohesion altogether through filling PTFE.Then, extrude lubricant (for example mineral spirits or glycol) with common pasty state and come lubricated material, and then extrude mashed prod through filling.Extrudate is rolled usually, and then is higher than 10% extensibility with per second under the temperature between 35 degrees centigrade and 327 degrees centigrade and is stretched 1.2 times to 5000 times rapidly, preferred 2 times to 100 times (according to these patents).If desired, before stretching, lubricant can be removed from extrudate so.Gained through the expansion porous fill that PTFE then soaks by being dissolved at about 2% to 70% tackiness agent in the varnish solution in the solvent, calendering or scrape to smear with blade and absorb tackiness agent.Then, the mixture that will wet is fixed on the tenter machine, and carries out the B sublevel subsequently under 165 degrees centigrade or about 165 degrees centigrade, lasts 1 to 3 minute.So the gained sheet tackiness agent that obtains is grouped into by following one-tenth usually: (a) PTFE of 9 to 65 weight %; (b) inorganic filler of 9 to 60 weight %, it is particle form; (c) be absorbed in the tackiness agent of 5 to 60 weight % in the vesicular structure through filling the PTFE net.At United States Patent (USP) 4,187,390 and 4,482,516 and other patent in the expansion PTFE substrate material of other type has been described.United States Patent (USP) 4,187,390 is especially interesting, because it has fully in depth studied O-fiber and node as the part of this type of substrate material, these is subdivided into height of node, node width, node ' s length and the restriction of O-fiber length equidimension.

In some known dielectric combinations, (for example, " FR4 " dielectric materials) as indicated above, bromine is used as a kind of in the composition constituent.Bromine is considered to be of value to provides humidity and flame retardant resistance, and helps to guarantee that resulting structures has high Tg.In a kind of known compositions, except that bisphenol-A (it is a kind of known industrial chemical that specially is used for Resins, epoxy (and other products)) and cresol novolac epoxy varnish resin, it is believed that this material constitutes about 30 weight % of described composition.Yet the applicant thinks that when using with some resin materials, the bromine of higher percent more and more is considered to undesirable owing to the degree of the electrical characteristic that reached the disadvantageous effect base resin so relatively.

The present invention has illustrated the important improvement to dielectric combination, and described dielectric combination for example then forms dielectric layer to be used to produce for example those dielectric combinations of the circuitized substrate of PCB on it.The feature of a particularly important of the present invention provides a kind of dielectric materials, except that will be hereinafter more other element of specific definition, described dielectric materials also comprises some silicas and reduces the bromine of a lot of amounts, thereby guarantee the characteristic of wanting that product technology has to be provided by bromine, and do not have the unwanted aspect that is considered to nowadays exist.When keeping necessary FR grade, reduce bromine content and caused the specific inductivity of laminating material to effectively reduce, because polarization reduces quantitatively.To define the additional favorable characteristics of this composition hereinafter in more detail.Believe that this type of invention is with the important advance in the representative technology.

Summary of the invention

Main purpose of the present invention is to improve the circuitized substrate technology.

Another purpose provides improved dielectric combination, and it is used in and forms dielectric layer in the circuitized substrate, and it can successfully be produced by using conventional manufacturing course.

Another purpose of the present invention provides this type of will be had with the substrate that is used for the high speed signal path and successfully merge and necessary a lot of combination of attributes things of wanting in relative rigorous environment (for example, those environment of high humidity).

According to one embodiment of the invention, a kind of dielectric combination is provided, it is suitable in the circuitized substrate, and described dielectric combination comprises the resin of first amount and the weighting material of second amount, and described dielectric combination only comprises small amount of bromine.

According to another embodiment of the present invention, a kind of circuitized substrate is provided, it comprises at least one conductive layer and at least one dielectric layer, described at least one dielectric layer comprises propping material and comprises the resin of first amount and the dielectric combination of second weighting material of measuring that this dielectric combination only comprises small amount of bromine.

Description of drawings

Do not have

Embodiment

In order to understand the present invention better,, following disclosure and appended claims are made reference with other and further purpose, advantage and its ability.

Adopt as used herein term " circuitized substrate " to be intended to represent a kind of substrate product, it comprises one or more dielectric layers and one or more conductive layers.As well known in techniques, this series products comprises printed circuit board (PCB) (a/k/a printed wiring board) and card, and chip carrier (being suitable for having the substrate of one or more electronic packages of semi-conductor chip for example mounted thereto).Usually, conductive layer is made up of copper or copper alloy, and the dielectric materials of previously known comprises previous materials, may the most extensive known material be the resin material that described " FR-4 " glass fibre is strengthened.In aforementioned patent and patent application case co-pending, describe the example of these two kinds of products in detail, and think and there is no need to be further described.

The circuitized substrate that is produced by dielectric combination taught herein is suitable in a lot of electronic products, and foremost in possible these products is the product that can be called as " information processing system ".As used herein, this term should be represented mainly to be designed to calculate, classify, handle (process), send, receive, retrieve, initiate, switch, store, show, show, measure, detect, write down, reproduce, handle (handle) or utilize any media of any type of information, information or data or the set of media for commercial affairs, science, control or other purpose.Example comprises the larger process device of Personal Computer and for example computer server and large scale computer.This series products is well-known in technology, and be also known as comprise PCB and other form circuitized substrate as its part, depend on its operational requirement, some products comprise several these class components.

As defined herein, composition of the present invention is with cloth propping material (for example glass fibre) when using, in circuitized substrate, provide dielectric layer, the bromine content that this demonstrates the specific inductivity that reduces, the dielectric loss factor that reduces, the cure shrinkage that reduces, the thermal expansivity (CTE) that reduces and reduces in addition.In brief, composition of the present invention only comprises small amount of bromine.When the amount of the bromine of definition in the resulting composition, the about 20 weight % or the amount still less of composition represented to equal in the term of employing " on a small quantity ".This is that composition overcomes the importance to the viewed undesirable characteristic mentioned above of one or more compositions with more these materials.

The present invention comprises a kind of dielectric combination, and it is suitable for the foregoing circuit substrate, and described dielectric combination comprises the resin of first amount and the packing material (weighting material hereinafter referred to as) of second amount.It should be noted that described composition only comprises small amount of bromine (account for 20 weight % of composition or still less).In an example, the amount of resin is actually the combination of three kinds of different resins materials, and preferably account for final composition about 40 to about 50 weight percents (%).In example more specifically, total amount of resin can account for about 44 weight % of composition.In these resins, account for 33 weight percents (%) of final composition with first kind of resin of the trade name sale of " ECN-1280 " resin by the Ciba-Geigy Corporationof Tarrytown in New York." ECN-1280 " resin is a Resins, epoxy, more particularly, is the cresol novolac epoxy varnish resin, and it can guarantee the low wet fastness in the gained dielectric layer.Second resin is reactive thermosetting resin of high molecular and the 6 weight % that account for composition.Preferred embodiment is sold with the trade name of " PKHS-40 " resin by the Inchem Corporation of the Rock Hill of South Carolina.In fact, " PKHS-40 " resin is high molecular thermosetting resin and the toughner that is used as described composition.The 3rd resin is four functional group's resins and the 5 weight % that account for composition weight.A purpose of this 3rd resin is to provide desired UV-fluorescent characteristic for final composition.

Composition of the present invention comprises the weighting material of aforementioned quantities.In an example, this weighting material is a silica, and accounts for about 10 to about 60 weight % of composition.Additional packing material comprises alumina, aluminum oxide, aluminium nitride, silicon nitride, silicon carbide, beryllium oxide, boron nitride, diamond powder, titanium oxide, pottery and its combination.A preferred embodiment of this type of silica is the Tatsumori of Tokyo Shibakoen Minato-ku 2-9-3 number by business location, and Ltd. (New York, New York, Tatsumori U.S.A., Inc. representative) sells with name of product " PLV-6 ".Another example is Tatsumori " PLV-4 " silica.The combination of these silicas also is possible.These silicas are spherical amorphous silicas, and are that the thermal expansivity (CTE) of gained dielectric layer provides decisive factor with described per-cent above.The spherical character of this weighting material allows the high volume filling of weighting material, and can not make that the melt viscosity of composition is too high so that can not eliminate general laminating technology.In a specific examples, can use this silica of about 13 weight %.Described silica can be the form of spherical or hemispherical amorphous fine-particle or be the form of hollow silica microballoon, or its combination.Silica filled material is the important element in the composition, because it allows to reduce cloth (propping material) composition, still reaches low (and character has more isotropy) CTE value of composition simultaneously.Comprise that this type of weighting material can cause providing to electroplating ventilating hole the isotropy CTE of additional reliability, it is the present composition and another attribute of the present invention.Comprise that silica also can improve electrical characteristic, because its some compositions that replace in the described cloth possess than low-k (Er) composition, described cloth has higher Er value.Because silica also has low water absorption character, has partly compensated the resin hydrophobic that weakens so comprise silica, it causes (hereinafter describing more) by the bromine content that reduces.Adding the particles filled thing of silica taught herein for example can increase the fragility of dielectric layer usually, and this is undesirable.Yet the interpolation of aforementioned " PKHS-40 " thermosetting resin has guaranteed that this type of fragility in the final layer is positioned at the acceptable level that reduces.In an example, each in the silica microparticle all has the size in about 200 dusts arrive about 35 microns scope, and preferred size is about 10 microns.Above-mentioned scope is not intended to limit the present invention, because other scope also can accept to be used for the present invention.

As mentioned above, the key character of composition of the present invention is only to utilize small amount of bromine in final composition, and the expression composition only comprises about 20 weight % or this type of material still less.This has guaranteed mentioned above and other local recognizable favorable characteristics of this paper.In an example, bromine is a part of adding the stiffening agent in the composition for this purpose to.More particularly, composition can comprise the tetrabromobisphenol-A of about 28 weight %, and a kind of this series products can trade name " TBBA " be buied from the Dead Sea Bromine of Israel Beer Sheva.In example more specifically, composition can comprise " TBBA " of about 28 weight %, itself contains 58% the bromine of having an appointment, and makes the total content of bromine only be about 16% altogether.(or more briefly, BisA) sell with Bisphenol A by trade name by the Dow Chemical of Midland of Michigan for employed another stiffening agent in the described composition.Bisphenol A is the compound that the combination from an acetone unit (acetone unit) and two phenol entities (phenol entity) draws, and by a lot of companies sale except that Dow Chemical.About 15 weight % of composition can use dihydroxyphenyl propane.Two kinds of stiffening agents will account for about 35 to about 55 weight % of composition altogether, and account for 43 weight % in a specific examples (comprise present with described amount above-mentioned both).

Composition of the present invention also preferably includes coupler, and preferably this type of coupler is a silane, only accounts for about 0.50 weight %.In a specific examples, silane can account for 0.43 weight % of composition.Preferred silane is γ-glycidyl propyl trimethoxy silicane of being sold with the trade name of " Z-6040 " silane by Dow Chemical.Other suitable silane comprises γ aminopropyltriethoxywerene werene and β-(3, the 4-epoxycyclohexyl) ethyl trimethoxy silane.As used herein coupler is used to participate in the chemical bonding of silica filled thing and resin, has also improved bonding between the employed conductive layer in gained dielectric materials and the circuitized substrate (for example copper).Silane directly adds in the resin, but is used for directly handling silica microparticle before also can be in merging to composition.

Composition defined herein also can comprise on a small quantity the glyoxal ethyline that can buy from the BASF AG that has business location at the Florham of New Jersey Park, with the catalyzer as Resins, epoxy.Only can use about 0.11 weight % of composition for this purpose.

Above-mentioned materials, these are resin, silica filled material, silane, glyoxal ethyline and stiffening agent (comprising the sort of of bromine), can mix with known colourless liquid methyl ethyl ketone (abbreviating MEK usually as), have the solid liquid varnish of about 70 weight % with generation with similar acetone smell as solvent.Then, this liquid varnish is coated on the desired propping material, the preferred embodiment of described propping material is cloth and more preferably is glasscloth that the glasscloth of a lot of types all is used for PCB and makes.The amount that is coated to the composition on the cloth depends on the final thickness of wanting of (for example laminated) dielectric layer of compacting.It should be noted that to comprise that silica filled material taught herein allows to use the woven fiber glass of thinner and lighter type, still reach desired thickness simultaneously, and also keep or improve the x-y of circuitized substrate and the dimensional change in the vertical plane simultaneously.The gained combination of silica filled thing and thinner, lighter cloth also improves the laser drill (for aforementioned through-hole is provided) of dielectric layer by the organic/inorganic homogeneity that increases material.Owing to the contact cause that reduce of glass fibre, also improved the insulation resistance reliability of laminating material with electro-conductive material.More significantly, the existence of silica filled material has improved the bounding force of copper coating, and plays the effect that improves anti-fragility and improve the CITC performance.

Woven fiber glass can flood with described matrix material, dry, " B sublevel " and then with normal way (being known as the PCB laminating technology) with hope other layer lamination as the part of finished product circuitized substrate, these other layer comprises conductive layer and other dielectric layer.Gains are the circuitized substrate with several height favorable characteristics defined herein.An example showing electricity, heat, physics and the chemically expansible characteristic of the key that can obtain in the following table by the composition that uses appended example.In general, the dielectric layer that uses teaching of the present invention and produced can have about 3.5 in about 4.0 the scope specific inductivity, during at about 140 degrees centigrade of Tg, 1MHz in about 190 degrees centigrade scope about 0.008 in about 0.012 the scope loss factor and in about 300 degrees centigrade of decomposition temperatures in about 350 degrees centigrade scope.

Example 1

In Glass Containers, (for example restrain (gm) ECN-1280 with 165, by New York, advanced Materials inBrewster, Huntsman sells), 141 gram tetrabromo-bisphenols are (by Baton Rouge Louisiana, AlbemarleCorporation sells with the trade name of Saytex CP-2000), 73 gram bisphenol-As are (by the Ohio, Haverhill, Sunoco Chemicals sells), 24 gram Epon 1031 (solid that contains 80 weight % among the MEK) are (by the Texas, the Houston, Resolution Performance Products sells) and 30 restrain PKHS-40 (solid that contains 40 weight % among the MEK) (by South Carolina, Rock Hill, InChem Corporation sells) mix with about 100 gram MEK, continue the long period, so that obtain homogeneous solution.About 0.6 gram glyoxal ethyline (catalyzer) and 50 gram MEK and 2.15 gram Z-6040 couplers (by Midland Michigan, Dow Corning sells) are mixed.Add to this solution in the previous mixture and uniform to obtain, the well-mixed composition of vigorous stirring.Use high-shear mixer that the silica filled thing PLV-6 of about 65 grams (by Japan, Tokyo 105, Tatsumori sale) is distributed in this solution.This composition is used to produce the material (being impregnated with the woven fiber glass of resin solution) that is called as the preimpregnation material and after a while with after lamination can be as the laminate of the part of circuitized substrate to produce.

Above-mentioned dispersion is used for applying the braiding woven fiber glass.Will be through the cloth of dipping at the air drying several minutes, and put into the baking oven of 140C subsequently, continue about 3 minutes.The preimpregnation material that technology produced thus has " on put forward " weight of 7.32 grams for 4 * 4 square inches of structures that comprise 8 synusia.Exert pressure and heat after, shown mobilely be about 37%.Test is the preimpregnation material laminate of making from then on by using 200p.s.i lamination pressure and 180 degrees centigrade of laminating temperatures, and shows the result in following table.

Table

Scope

Electrical characteristic

Dk (specific inductivity) @1-2.5GHz (average) 3.8-4.0

Loss factor 0.008-0.012 during 1MHz

Thermal property

Tg (DSC mid point) (degree centigrade) 140-190C

Tg (TMA) (degree centigrade) 130-180C

Decomposition temperature (degree centigrade) 300-330C

Physical property

% humidity, 24hr RT 0.15-0.30%

% humidity 1hr, PCT 0.45-1.2%

Modulus (M psi) 3.4-4.0

Elongation (%) 0.5-2.0

Thermal expansion

Under Tg

x 14-22ppm/C

y 14-22ppm/C

z 40-65ppm/C

On Tg

x 8-12ppm/C

y 5-10ppm/C

z 250-300ppm/C

Recognize further that as description content the specific end use of the formed circuitized substrate of this paper is as chip substrate or PCB or for example by the part of other Electronic Packaging product of those products of transferee's produce and market of the present invention according to this paper.A particular instance is the chip carrier that the title (Hyper-BGA is EndicottInterconnect Technologies, the registered trademark of Inc.) with the Hyper-BGA chip carrier is sold.Certainly, the present invention is not limited to chip carrier or even more high-grade PCB.Should also be clear that, (also be called " core " more than this type of circuitized substrate, specific examples is called as " power supply core ", if described core comprises one or more voltage planes and therefore mainly serves with this ability) can be incorporated in examples of such carriers or the PCB, depend on the desired operational requirement of the finished product.Such as hereinafter definition, described " core " can be easy to and other layer (comprising conductor and dielectric medium) " piling up ", and combines (preferably using conventional PCB laminating technology) so that form multilayer carrier or multi-layer PCB.Then, make the laminate of formation like this stand further processing, comprise that conventional photoetching process is to form circuit pattern on its outer conducting layer.As mentioned below, this type of external print can comprise conductive pad, and for example the conductor of soldered ball can be positioned on the described conductive pad, so that when needed described structure is connected to for example other assembly of semi-conductor chip, PCB and chip carrier.Therefore, unique teaching of the present invention can be suitable for a large amount of Electronic Packaging products.

Though showed and described the embodiment that is considered to the preferred embodiment of the present invention at present, but the those skilled in the art is Jiang Ming Liao, can not break away under the situation of the scope of the present invention that defines by appended claims, the present invention is being made various changes and modification.

Claims (21)

1. dielectric combination that is suitable in the circuitized substrate, described dielectric combination comprise the resin of first amount and the weighting material of second amount, and described dielectric combination only comprises a spot of bromine.

2. dielectric combination according to claim 1, the described resin of wherein said first amount comprises Resins, epoxy.

3. dielectric combination according to claim 2, wherein said Resins, epoxy comprises the cresol novolac epoxy varnish resin.

4. dielectric combination according to claim 2, the described resin of wherein said first amount further comprises thermosetting resin.

5. dielectric combination according to claim 4, the resin of wherein said first amount account for about 40 to about 50 weight % of described dielectric combination.

6. dielectric combination according to claim 1, the described weighting material of wherein said second amount is selected from by alumina, aluminum oxide, aluminium nitride, silicon nitride, silicon carbide, beryllium oxide, boron nitride, diamond powder, titanium oxide, silica, pottery and its group that forms.

7. dielectric combination according to claim 6, wherein said weighting material comprises silica.

8. dielectric combination according to claim 7, wherein said silica are selected from by spherical amorphous silica, hemispherical amorphous silica, hollow silica microballoon and its group that forms.

9. dielectric combination according to claim 7, wherein said silica account for about 10 to about 60 weight % of described dielectric combination.

10. dielectric combination according to claim 1, it further comprises stiffening agent.

11. dielectric combination according to claim 10, wherein said stiffening agent comprises tetrabromobisphenol-A and bisphenol-A.

12. dielectric combination according to claim 10, wherein said stiffening agent account for about 35 to about 55 weight % of described composition.

13. dielectric combination according to claim 1, it further comprises coupler.

14. dielectric combination according to claim 13, wherein said coupler comprises silane.

15. dielectric combination according to claim 1, it further comprises propping material, and the combination of described dielectric combination and described propping material is suitable for use in dielectric layer in the described circuitized substrate with formation.

16. dielectric combination according to claim 15, wherein said propping material comprises glasscloth.

17. dielectric combination according to claim 15, wherein said dielectric layer have the specific inductivity that arrives in about 4.0 scopes about 3.5.

18. dielectric combination according to claim 15, wherein said dielectric layer have at about 140 degrees centigrade of Tg that arrive in about 190 degrees centigrade of scopes.

19. dielectric combination according to claim 15, wherein said dielectric layer have the loss factor that arrives in about 0.012 scope about 0.008 when 1MHz.

20. dielectric combination according to claim 15, wherein said dielectric layer have in about 300 degrees centigrade of decomposition temperatures that arrive in about 350 degrees centigrade of scopes.

21. circuitized substrate, it comprises at least one conductive layer and at least one dielectric layer, described dielectric layer comprises propping material and dielectric combination, and described dielectric combination comprises the resin of first amount and the weighting material of second amount, and described dielectric combination only comprises a spot of bromine.