JP2007266606A - Fluoropolymer insulating composition for circuit board, and circuit board including same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating composition which can be utilized to form an insulating layer in a circuit board and which can be produced successfully using conventional manufacturing process. <P>SOLUTION: The fluoropolymer insulating composition includes: first fluoropolymer having a first melting point, second fluoropolymer having a second melting point lower than the first melting point, a first inorganic filler having a first thermal conductivity, a second inorganic filler having a thermal conductivity lower than the first thermal conductivity, and further a supporting member formed of a fiber-glass cloth. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an insulating composition for use in a circuit board used for a printed circuit board and a chip carrier, and the composition may be used alone or in combination with a support structure such as glass fiber. And is useful for forming an insulating layer that can be used as part of a substrate as an electrically insulating layer between conductive layers such as signal, power and ground layers that form part of the final structure. More specifically, the present invention relates to a composition that ensures that such products can be provided with dense circuitry in such conductive layers.

  Circuit boards such as printed circuit boards and laminated chip carriers used in many of today's technologies allow the formation of multiple circuits with minimal volume and space. As noted above, these end products typically include a “stacked” layer comprising at least one of a signal layer (line), a ground layer (line), and a power supply layer (line), at least one Separated from each other by two layers of insulating material. Circuit lines or pads (eg, signal layers) are often electrically connected to each other by plated holes that penetrate the insulating layer. A plated hole is called a “via” when it is inside, and it is called a “blind via” when it extends from the outer surface of the substrate to the inside to a predetermined depth and substantially penetrates the substrate. If so, it is often called “plated through hole” (PTH). As used herein, the term “through-hole” means that all three types of substrate openings are included.

  The complexity of the products described herein has increased significantly over the last few years. For example, a mainframe computer printed circuit board (PCB) can have 36 or more layers, and the thickness of the stack is approximately 0.250 inches (250 mils). These substrates are typically designed to have 3 or 5 mil wide signal lines and 12 mil diameter through holes. Due to the high density of circuits in many of today's products such as printed circuit boards and chip carriers, it is desired in the industry that signal lines be less than 2 mils wide and through holes should be less than 2 mils in diameter. Yes.

  The most well-known commercial methods (especially those described herein) do not provide an economic view of the standards desired by the industry. Known methods for printed circuit boards, chip carriers, etc. include the formation of a separate inner layer circuit (circuit layer), which inner layer circuit is coated on a copper-covered inner layer substrate with a photosensitive layer or It is formed by coating a photosensitive film. The photosensitive coating is imaged and developed, and the exposed copper is etched to form conductive lines. After etching, the photosensitive film is peeled from the copper leaving a circuit pattern on the surface of the inner substrate. This method is also referred to as photolithography in printed circuit board technology and does not appear to require further description.

  After the individual inner layer circuits are formed, the multilayer stack is formed by layup of the inner layer, ground layer, power layer, etc., these layers are made of incompletely cured materials (typically Are separated from each other by an insulating prepreg typically having a layer of glass (generally glass fiber) fabric impregnated in a B-stage epoxy resin. The top and bottom layers of the laminate usually consist of an epoxy planar substrate with glass fibers coated with copper, the copper coating having the exterior surface of the laminate. The laminate is laminated and heated and pressurized to form a monolithic structure to fully cure the B-stage resin. The laminate thus formed has a metal (usually copper) coating on both outer surfaces thereof. The outer circuit layer is formed in a copper cladding using a method similar to that used to form the inner layer circuit. The photosensitive film is affixed to the copper coating. The coating is exposed to the patterned activation electromagnetic radiation and developed. An etching solution is used to remove the copper exposed by developing the photosensitive film. Finally, the remaining photosensitive film is removed, and an external circuit layer is formed.

  Through holes (also referred to as interconnects) are often used to electrically connect individual circuit layers within a structure to each other and to the outer surface, and generally pass through all or part of the stack. The through-hole is usually formed by drilling through the laminate at a suitable location before forming a circuit on the outer surface. After several pretreatment steps, the hole walls are contacted with the plating catalyst and catalyzed to form a circuit layered conductive path, typically by contact with an electroless or electrolytic copper plating solution. . After the formation of the conductive through hole, the external circuit or the external layer is formed using the above method. The insulator used for the substrate must promote the formation of such through holes.

  A semiconductor chip or other electrical component or both are mounted at appropriate locations on the external circuit layer of the multilayer stack, typically using solder mount pads to bond the electrical component to the printed circuit board. Electrical components are often electrically connected as desired to circuitry within the structure through conductive through holes. Solder pads are typically formed by applying an organic solder mask coating over the external circuit layer. The solder mask is affixed by screen coating a liquid solder mask coating material on the surface of the external circuit layer using a screen having an opening that defines the area in which the solder mount pad is to be formed. Alternatively, a photoimageable solder mask is coated on the substrate, exposed and developed to form an array of openings that define the pads. The opening is then coated with solder using methods known in the art such as wave soldering.

  The development of new materials that raise the limits of the electrical and thermal performance of currently available technologies by the need for ever-evolving and faster circuit boards used in many of today's new products (eg computers) Is required. For high speed applications, it is essential to have a very high density conductive circuit pattern on a low dielectric constant insulating material. Conventional prepreg laminates for circuit boards traditionally consist of a glass cloth reinforced base material impregnated with resin. This glass cloth is also referred to in the industry as “FR4” insulating material (FR stands for Flame Retardant, 4 stands for its relative value).

  The epoxy / glass fiber laminates used in some current products typically contain about 40% by weight glass fiber and about 60% by weight epoxy resin and have a relatively high dielectric constant (Er). In general, sometimes exceeding 4.0. Such a relatively high dielectric constant causes electrical pulses (signals) to be generated in adjacent signal circuit lines, reducing the speed of propagation and causing excessive signal time delay. As new computer systems become faster, system cycle times need to be shorter. Delay times due to signal movement in PCBs and other circuit boards used in such products become serious and therefore there is a need for low dielectric constant materials. Many products are required to have an overall dielectric constant of 2.8 or less. Such a low dielectric constant cannot be obtained without new materials. This is because the dielectric constant of the conventional ER4 epoxy and the general glass fiber as described above is in the range of 4-6. The effective dielectric constant of such composite materials can usually be approximated by a simple weighted average of the dielectric constants of the individual components and the volume fraction contained in the composite material. As explained further below, the above compositions are often heavily weighted to the brominated parts to ensure the desired FR ratio.

  Substrates comprising fluoropolymer insulating materials are known and include what are referred to as “pure” fluoropolymer substrates. One example of such a known material used today is polytetrafluoroethylene (PTFE), which has a dielectric constant of approximately 2.0. However, the use of only such materials in the construction of circuit board laminates is sometimes found to be impractical due to poor mechanical properties and chemical inertness of this material. An alternative is to use a fluoropolymer as one of the composite laminates (fibers in the reinforced fabric). An example of this is W. W., Newark, Delaware. L. A treated PTFE woven prepreg manufactured by Gore & Associates. When this type of fabric is used in place of glass fiber in a conventional epoxy / glass fiber laminate, the dielectric constant drops to 2.8. However, the use of this fabric causes certain disadvantages. Due to the relatively low modulus of pure PTFE, thin laminates formed from these materials are not very rigid and require special handling. Even when a laminate incorporating a PTFE fabric is drilled, uncut PTFE fibers tend to protrude into the drilled holes and are difficult to remove. In order to obtain good plating adhesion, the exposed PTFE surface must be treated by the use of expensive chemicals or plasma treatment, which are extremely flammable in a nitrogen atmosphere. In this plasma treatment, high aspect ratio through holes must be penetrated in order to obtain good plating adhesion. Of course, one of the most disadvantages of PTEE fabric lamination is cost, which costs not only the additional processing requirements and costs associated with equipment changes, but also the high cost of purchasing the prepreg material itself.

  Further, with respect to fluoropolymer insulating materials, Patent Document 1 (U.S. Pat. No. 5,055,342; name “fluorinated polymer composition and its manufacture and use thereof”) issued on Oct. 8, 1991, Fluorinated polymer compositions exhibiting a dielectric constant and a low coefficient of thermal expansion are described and include a fluorinated polymer material and a silica or quartz filler having an average particle size of 7 microns or less, or both . The layer of composition is obtained by applying the composition to a substrate and heating the composition to a temperature sufficient to melt the composition. This filler material is selected from the group consisting of silica, quartz, hollow microspheres (microspheres) and mixtures thereof.

  Another characteristic that affects the performance of other laminated insulating materials is the coefficient of thermal expansion (CTE). It is desirable to closely match the coefficient of thermal expansion with its neighbors in the X and Y directions of the insulating material. This prevents cracks in the solder connections that join the device with the PCB mounted on the surface, or prevents warping of the printed circuit board. The coefficient of thermal expansion in the X and Y directions depends on the glass fibers in the matrix. However, these fibers do not control the coefficient of thermal expansion in the Z direction. The coefficient of thermal expansion in the Z direction must also be controlled during the thermal cycle to prevent cracking of the copper plated through holes.

  In solder connection processing and rework and other manufacturing processes, heat is generated during the flow of current during operation of the finished substrate or when exposed to temperature fluctuations during shipment or storage. As a method of changing the coefficient of thermal expansion, there is use of a filler (filler).

  The filler can be bound to the matrix polymer and is added by the use of a coupling agent (silane is often used).

  The coupling agent enhances the bond between the filler and the polymer and optimizes the interfacial interface, which further enhances the electrical and mechanical performance. Various types of fillers can affect the dielectric loss of the composite.

  When the inflection point called the glass transition temperature (Tg) is reached, the coefficient of thermal expansion of the prepreg insulating material changes significantly. It is desirable for the insulating material to have a high glass transition temperature to minimize stress, since the expansion rate of the insulating material increases significantly when the glass transition temperature is reached. Insulating materials based on epoxy novolacs, for example, are believed to have a relatively high glass transition temperature and are typically 150 degrees Celsius or higher. Other properties associated with high glass transition temperatures are often poorly hygroscopic and chemically resistant.

  A known material for satisfying many of the above requirements is Patent Document 2 (US Pat. No. 5,126,192; title of invention “Flame-retardant, low-insulation, invariant microsphere-filled laminate”) (June 30, 1992) Issuance). According to the teachings of this patent, a resin / silane treated microsphere / carrier structure prepreg is prepared, B-stage cured, and vacuum laminated. The impregnation mixture is prepared by adding a predetermined amount of microspheres to the resin / solvent mixture, resulting in a packing factor of, for example, about 50% when the solvent is eliminated. Low shear mixing techniques must be used to prevent damage to the microspheres. Since these microspheres are spherical, the microspheres can be quickly mixed into the solution and do not increase the viscosity of the solution to such an extent that impregnation becomes difficult. The combination of microsphere size and packing factor allows the filled insulating material to withstand the thermal and hot pressure cycles of the stack without damaging the hollow microsphere. According to this patent, less than 2% microsphere failure was observed at lamination pressures up to 500 pounds per square inch (PSI).

  When damage occurs, generally the largest microspheres collapse first. Hollow silica microspheres contain 2% or less sodium monoxide and are noted to be acceptable for those less than 40 microns in diameter (Grace Syntactics). , Inc.) clearly uses the name "SDT28"). The company's "SDT-60" microspheres (99% less than 25 microns) are listed as preferred fillers. The microspheres are treated with a silane-based coupling agent that is suitable for use with certain resins. A particularly suitable coupler for these formulations is also described. One of the binding admixtures is described as a combination of vinyl silane and amino silane and is described as having excellent moisture resistance and acceptable wetting dielectric loss performance. Silane resins are said to bind filler particles in the resin matrix and minimize the size of the interfacial area between the resin matrix and the microspheres. The carrier / reinforcing material of this patent may be a known shell type reinforcement such as glass or polytetrafluoroethylene (PTFE). The selected carrier fabric will depend largely on the properties desired for the finished laminate. These include predetermined thickness, dielectric constant, coefficient of thermal expansion, and any product application. Carrier materials include glass fiber woven and glass nonwoven fibers and polymer woven and mats. An organic film such as a polyimide film is also used. Low dielectric constant fabrics such as D-glass, Kevlar and Nomex (both registered trademarks of EI DuPont de Nemours and Company), aramids, poly-p-phenylene, Benzo bis thiazole (poly p-phenylene benzobisthiazole), poly p-phenylene benzo bis oxazole (poly p-phenylene benzobisoxazole), polyether ether ketone (Polyetheretherketone), quartz terro (z) ), S-glass, etc. can be used in the formulation. This stiffener can be in a mixed and woven form or in a mixed form.

  Another known material designed for use on circuit boards and intended to meet the above requirements of today's high speed products is US Pat. Patent No. 6,207,595; “Lamination and manufacturing method thereof”). In this patent, the woven material of the insulating layer is made of a cloth material that has a sufficiently small amount of particles and a sufficient amount of resin material to completely cover the cloth member having the particles. Beyond the highest protruding point (i.e., the woven material is thicker and passes certain test criteria (known as HAST Level A test in '595). This means in 595 to include dry film, excess binder, damaged filaments, and whole surface debris, as one process to improve the weaving process and minimize twist damage. To suppress, it is stated that sizing of polyvinyl alcohol, corn starch and lubricating oil is applied to the fiber strands before weaving. It is removed by the process and cleans the filaments of lubricants and other materials, however, some sizing is left randomly as particles, covering the woven fabric containing the particles with a certain amount of cured resin material. This resin may be an epoxy resin, often used for “FR4” composites, and a resin material based on bismaleimide triazine (BT) is also used in the structure of this patent. More preferably, the resin is a phenolic curable resin material known in the printed circuit board industry, so this patent requires continuous fibers (through-through required for the final product). Over the entire width (or length) of the insulation layer, except for accidental interruptions (which "damage" these fibers) caused by drilling holes Thus, the above-described problems associated with fiber strands exposed in through-holes can occur in the processing steps of this patent and the resulting structures.

  In US Pat. No. 5,418,689, a printed circuit board is described, wherein the insulating substrate includes a thermoplastic resin, a thermosetting resin, or both. The thermosetting polymeric materials described in this patent include epoxy, phenolic substrates, polyimides and polyamides. Examples of phenolic materials include copolymers of phenol, resorcinol and cresol. Examples of thermoplastic polymeric materials include polypropylene, polytetrafluoroethylene, polysulfone, polycarbonate, nitrile rubber, ABS polymer, and polytetrafluoroethylene, chlorotrifluoroethylene, fluorinated ethylene propylene polymer, polyvinylidene fluoride and Examples thereof include fluorocarbon polymers such as polyhexafluoropropylene. The insulating material may be a filler, or a molded article of a polymer having a reinforcing agent such as a polymer filled with glass, or both. The “FR4” epoxy composition used in this patent consists of 70-90 parts of brominated polyglycidyl ether of bisphenol A, 3-4 parts of dicyandiamide and 0.2-0.4 parts of tertiary amine. Contains tetrakis (hydroxyphenyl) ethane tetraglycidyl ether to cure (all parts are parts by weight per 100 parts of resin solids). Another “FR4” epoxy composition comprises about 25 to about 30 parts by weight of brominated diglycidyl ether of bisphenol A having an equivalent weight of about 350 to about 450 and bisphenol A having an equivalent weight of about 600 to about 750. From about 10 to about 15 weight percent of a brominated glycidyl ether and from about 55 to about 65 parts by weight of at least one exposed non-linear novolak having at least 6 terminal epoxy groups, and a suitable curing or curing agent or You may use what contains both of these. A further “FR4” epoxy composition comprises 70-90 parts of brominated polyglycidyl ether of bisphenol A and tetrakis (hydroxyphenyl) ethane tetraglycidyl ether cured with 0.8-1 phr of dimethylimidazole. 10 to 30 parts. Yet another "FR4" epoxy composition uses tetrabromobisphenol A as the curing agent with dimethylimidazole as the solvent.

  In US Pat. No. 6,323,436, printed circuit boards are used in place of reinforcing agents commonly used in the electronics industry, described as glass fibers woven in this patent. Manufactured by impregnating woven aramid chopped fiber mat or thermoplastic liquid crystalline polymer (LPC) paper. The aramid reinforcement has a random (planar direction) orientation of p-aramid (poly p-phenylene terephthalamide) composed of Kevlar (Kevlar is a registered trademark of EI DuPont de Nemours). It has a dielectric constant of 4.0, has a dielectric constant of 4.0, and is compared with the dielectric constant of 6.1 for standard E glass cloth. The low dielectric constant of the nonwoven aramid reinforcement achieves faster signal transmission, increases wiring density, reduces crosstalk (important for high I / O chip and miniaturization) Is increasing). As described in this patent, p-aramid fibers are isotropic in the transverse direction and have an axial coefficient of thermal expansion of about -3 to about -6 ppm per degree when combined with a thermosetting resin. The final composition is said to have a coefficient of thermal expansion that can be controlled and adjusted to match the coefficient of thermal expansion of the silicon or semiconductor chip in the range of about 3 to about 10 ppm / ° C. Thermoplastic liquid crystal polymerized paper is a material called Vecrus (registered trademark of Hoechst Celanese). For the thermoplastic liquid crystal polymer paper, Vectra polymer (Vectra is a registered trademark of Hoechst Celanese) is used. According to this patent, the dielectric constant is 3.25, and the loss factor is 0.024 at 60 Hz. The polymerized paper is UL94-V0 rated and has a planar thermal expansion coefficient of less than 10 ppm / ° C. The advantages of this material over an aramid mat are low dielectric constant and very low hygroscopicity (less than 0.02%). Nonwoven aramid or thermoplastic liquid crystal polymerized paper is used with a thermosetting resin to form the final composite substrate. Examples of thermosetting resins described as useful in this patent include epoxies, cyanate esters, bismaleimides, bismaleimide triazines, maleimides or combinations thereof. Next, the low thermal expansion coefficient reinforcement impregnated with resin is partially cured to “B” stage to form a prepreg, which is then cut, laminated, and built-up board with an external copper plate (Subcomposite) is formed.

  Yet another type of known insulating material used in circuit boards is what is known as an “expanded PTFE” material, of course PTFE refers to polytetrafluoroethylene. A more common example of such a material is the Teflon® (sold by EI DuPont de Nemours) mentioned above. For example, in Patent Document 6 (US Pat. No. 5,652,055), it functions as an adhesive layer in various adhesive applications (such as circuit board stacking, multichip modules, and other electrical applications). Suitable adhesive sheet (or “bond film”) materials are described. This adhesive sheet is described as being formed from an expanded Teflon (registered trademark) material such as that described in US Pat. No. 3,953,566. Preferably, this material is filled with an inorganic filler and formed as follows. The ceramic filler is mixed in an aqueous dispersion of PTFE produced by dispersion. The size of the small particle filler is generally less than 40 microns, and preferably less than 15 microns. This filler is introduced at 10 to 60 weight percent, preferably 40 to 50 weight percent of PTFE with respect to the composite impregnated with the final resin prior to solidification. The filled PTFE dispersion is then coagulated together, typically by rapid stirring. Next, solidified, filled PTFE is added. Next, the filled material is lubricated with a general paste extrusion lubricant (such as mineral spirit or glycol), and the paste is extruded. The extrudate is usually calendered and has an elongation of more than 10% per second between 35 and 327 degrees Celsius, according to this patent 1.2 to 5000 times, preferably 2 to 100 times. Doubled rapidly. This lubricant can be removed from the extrudate prior to stretching. The stretched, porous, filled PTFE is then absorbed into the adhesive by dipping, calendering, or doctor blading on about 2% to 70% adhesive varnish in solvent. The wet composition is then fixed to a tenter and then placed at about 165 degrees Celsius for 1-3 minutes and cured to stage B. The resulting sheet adhesive comprises (a) 9 to 65 weight percent PTFE, (b) 9 to 60 weight percent inorganic filler (in the form of particles), and (c) a porous PTFE web filled. Consists of 5 to 60 weight percent adhesive absorbed in the structure. Other types of stretched PTFE substrate materials are described in US Pat. No. 4,187,390, US Pat. No. 4,482,516, and others. US Pat. No. 4,187,390 is particularly interesting. Because it substantially studies both the nodes and fibers used as part of such substrate material, it is subdivided into node height, node width, node length, and fibril length size constraints.

  US Pat. No. 4,849,284 describes an electrical substrate material based on a rigid printed wiring board material and a ceramic-filled fluoropolymer to form an integrated circuit chip carrier. Yes. According to the authors, this material has improved electrical performance compared to other printed wiring board materials and circuit chip carriers, and its low thermal expansion coefficient and the corresponding properties of these board materials are related to surface mount reliability and As a result, the plated through hole reliability is improved. The electrical substrate material includes polytetrafluoroethylene filled with silica and a small amount of micro-glass fibers. A ceramic filler (silica) is coated with a silane coating material, which forms a ceramic hydrophobic surface and improves tensile strength, peel strength, and dimensional stability.

  In some known insulating compositions, bromine is used as one of the components as described above (eg, “FR4” insulating material). It is believed that bromine is beneficial to provide moisture resistance and flame resistance and to help ensure a high glass transition temperature of the structure. In one known composition, this material constitutes about 30 percent by weight of the composition, and bisphenol, a known chemical that is intended for use in epoxy resins (and other products) and cresol novolac type epoxy resins. Added to A.

  US application Ser. No. 10 / 812,890 filed Mar. 31, 2004 (Title of Invention “Circuit Board, and Method for Manufacturing the Same, Electric Device Assembly Using the Same, and Information Processing System Using the Same”) Inventor “R-Jap et al.”) Describes circuit boards, electrical equipment assemblies, and information processing systems that can employ insulating layers manufactured using the insulating compositions taught herein. Has been.

  U.S. Application No. 10 / 812,889, filed Mar. 31, 2004 (Invention "Insulating Composition for Forming Insulating Layer for Circuit Board", Inventor "R-Jap et al.") Describes an insulating composition that forms an insulating layer that can be used in circuit boards (printed circuit boards, chip carriers, etc.). Such a layer includes a cured resin material and a predetermined weight percent of particulate filler, and thus does not include long fibers, semi-long fibers, or the like as part thereof.

  US application Ser. No. 10 / 920,235 filed Aug. 18, 2004 (Title of Invention “Low Moisture Absorption Circuit Board, and Manufacturing Method, Electrical Equipment Assembly Using the Same, and Information Using the Same” Processing system ", inventor" I Memis et al. ") With a first layer of insulating material comprising a low moisture absorbing polymer resin combined with a knotted fluoropolymer web encased in the resin A substrate is described. The insulating layer formed from this combination does not include long fibers or half-long fibers as a part thereof. The circuit board further includes at least one circuit layer disposed on the first insulating layer. There are also provided an electrical equipment assembly, a method for forming the board, and an information processing system (for example, a computer) incorporating the circuit board of the present invention as part thereof.

  U.S. Application No. 11 / 086,323, filed March 23, 2005 (Title of Invention "Low Moisture Absorption Circuit Board, and Method for Manufacturing the Same, Electrical Equipment Assembly Using the Same, and Information Using the Same" Treatment system ", inventor" I Memis et al. ") A first insulating sublayer having a plurality of fibers having a low coefficient of thermal expansion and a second insulating sublayer of low moisture absorption resin (long fibers or semi-fibers). A circuit board is described that includes a composite material layer that does not include long fibers or the like as part thereof. The substrate further comprises at least one conductive layer as part thereof. There are also provided an electrical equipment assembly, a method for forming the board, and an information processing system (for example, a computer) incorporating the circuit board of the present invention as a part thereof.

This application is a partially pending application of US patent application Ser. No. 10 / 812,890. All the above applications are assigned to the same assignee as the assignee of the present application.
US Pat. No. 5,055,342 US Pat. No. 5,126,192 US Pat. No. 6,207,595 US Pat. No. 5,418,689 US Pat. No. 6,323,436 US Pat. No. 5,652,055 U.S. Pat. No. 3,953,566 U.S. Pat. No. 4,849,284 U.S. Pat. No. 4,187,390 U.S. Pat. No. 4,482,516

  The main objective of the present invention is to enhance circuit board technology.

  Another object of the present invention is to provide an improved insulating composition that can be used for forming an insulating layer of a circuit board and can be suitably produced using a conventional manufacturing method. is there.

  Yet another object of the present invention is to provide a composition having many desirable properties necessary to be suitably incorporated into a substrate for high speed signal transmission in relatively harsh environments (eg, humid).

  According to one embodiment of the present invention, an insulating composition made for a circuit board is provided, the insulating composition comprising first and second fluoropolymers and first and second inorganic fillers. The first fluoropolymer has a first melting point, the second fluoropolymer has a second melting point lower than the first melting point, and the first filling The material has a first thermal conductivity, and the second filler has a thermal conductivity lower than the first thermal conductivity.

  According to another embodiment of the present invention, at least one conductive layer, at least one insulating layer comprising an insulating composition having first and second fluoropolymers, and first and second inorganic fillers, The first fluoropolymer has a first melting point, and the second fluoropolymer has a second melting point lower than the first melting point. The first filler has a first thermal conductivity, and the second filler has a thermal conductivity lower than the first thermal conductivity. A circuit board is provided.

  That is, the present invention first provides an insulating composition that can be used in a circuit board, and includes a first fluoropolymer having a first melting point and a second melting lower than the first melting point. A second fluoropolymer having a point, a first inorganic filler having a first thermal conductivity, and a second inorganic filler having a thermal conductivity lower than the first thermal conductivity. It is characterized by this.

  In the insulating composition according to the present invention, the first and second inorganic fillers include particles having a size of about 10 microns or less, and these particles are spherical. .

  On the other hand, the first and second inorganic fillers constituting the insulating composition are alumina, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, boron nitride, diamond powder, titanium oxide, silica, It is selected from the group consisting of ceramics and combinations thereof.

  When silica is selected as the first and second inorganic fillers, the silica is selected from the group consisting of spherical amorphous silica, hemispherical amorphous silica, hollow silica fine particles, and combinations thereof. Is.

  The first and second fluoropolymers employed in the present invention belong to a polytetrafluoroethylene system and constitute about 50 to 90 weight percent of the composition. The second filler comprises about 10-50 weight percent of the composition.

  The insulating composition further includes a support member, and the insulating composition and the support member are combined to form an insulating layer that can be used in the circuit board. The member is typically made of glass fiber cloth.

  The first melting point of the insulating composition is in the range of about 300 degrees Celsius to about 350 degrees Celsius, and the second melting point is in the range of about 200 degrees Celsius to about 280 degrees Celsius. And the first thermal conductivity is in the range of about 600 W / mK to about 2000 W / mK, and the second thermal conductivity is in the range of about 5 W / mK to about 400 W / mK.

The insulating composition according to the present invention includes a third fluoropolymer having a melting point lower than the first melting point of the first fluoropolymer and the second melting point of the second fluoropolymer. It may also contain.
The method according to claim 1.

The circuit board according to the present invention includes a first fluoropolymer having a first melting point, a second fluoropolymer having a second melting point lower than the first melting point, and a first thermal conductivity. And at least one insulating layer having an insulating composition including a first inorganic filler having a second thermal conductivity lower than the first thermal conductivity, and the at least one insulating layer And at least one conductive layer disposed thereon.
A circuit board characterized by that.

  In this circuit board, the at least one conductive layer is made of copper or a copper alloy, and the first and second inorganic fillers include particles having a size of about 10 microns or less. The particles have a spherical shape, and the first and second inorganic fillers are alumina, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, boron nitride, diamond powder, titanium oxide, silica, Selected from the group consisting of ceramics and combinations thereof.

When silica is employed as the first and second inorganic fillers constituting the circuit board, the silica is composed of spherical amorphous silica, hemispherical amorphous silica, hollow silica fine particles and Selected from the group consisting of those combinations.
The circuit board according to claim 16.

  Also, the first and second fluoropolymers belong to a polytetrafluoroethylene system and constitute about 50 to 90 weight percent of the composition, and the first and second fillers are About 10 to 50 weight percent of the composition.

  The circuit board according to the present invention further includes a support member, and the insulating composition and the support member are combined to form an insulating layer that can be used in the circuit board. The support member may be made of a glass fiber cloth.

  The first melting point in the circuit board according to the present invention is in the range of about 300 degrees Celsius to about 350 degrees Celsius, and the second melting point is in the range of about 200 degrees Celsius to about 280 degrees Celsius. It is in. The first thermal conductivity is in the range of about 600 W / mK to about 2000 W / mK, and the second thermal conductivity is in the range of about 5 W / mK to about 400 W / mK.

  Furthermore, the circuit board of the present invention further includes a third fluoropolymer having a melting point lower than the first melting point of the first fluoropolymer and the second melting point of the second fluoropolymer. is there.

As described above, the present invention
“An insulating composition that can be used in circuit boards,
A first fluoropolymer having a first melting point and a second fluoropolymer having a second melting point lower than the first melting point;
A first inorganic filler having a first thermal conductivity, and a second inorganic filler having a thermal conductivity lower than the first thermal conductivity;
Insulating composition characterized by comprising "
The main feature of the structure is to provide an insulating composition that can be used for forming an insulating layer of a circuit board and can be suitably produced using a conventional manufacturing method. This can improve circuit board technology.

  That is, the present invention is an insulating composition for forming an insulating layer that can be used in a circuit board such as a printed circuit board and a chip carrier, and the composition comprises at least two fluoropolymers and two It contains an inorganic filler and has many desirable properties necessary to be suitably incorporated into a substrate for high-speed signal transmission in a relatively severe environment (for example, high humidity).

The present invention also provides:
"A circuit board,
A first fluoropolymer having a first melting point, a second fluoropolymer having a second melting point lower than the first melting point, and a first inorganic filler having a first thermal conductivity and At least one insulating layer having an insulating composition comprising a second inorganic filler having a thermal conductivity lower than the first thermal conductivity;
At least one conductive layer disposed on the at least one insulating layer;
Circuit board characterized by comprising "
And can provide a circuit board having many desirable characteristics necessary to be suitably incorporated into a board for high-speed signal transmission in a relatively severe environment (for example, high humidity). is there.

An insulating composition for forming an insulating layer that can be used in a circuit board such as a printed circuit board and a chip carrier, the composition containing at least two fluoropolymers and two inorganic fillers .

  For a better understanding of the present invention and other further objects, advantages and functions, reference is made to the following description and appended claims.

  As used herein, the term “circuit board” means a board product having one or more insulating layers and one or more conductive layers. Such products known in the art include printed circuit boards (a / k / a printed wiring boards) and cards, and chip carriers (substrates having one or more electronic components such as semiconductor chips).

  Circuit boards made from the insulative compositions described herein can be used in many electrical products (of which the perhaps best known is called an “information processing system”). As used herein, this term refers to the calculation, classification, processing, transmission, reception, retrieval, transmission of any form of information, intelligence, or data for business, scientific, control, or other purposes. It shall mean a means or collection of means designed primarily to perform switching, storage, display, explicit, measurement, detection, recording, playback, processing, or use. Examples include personal computers and large processors such as computer servers and mainframes. Such products are well known in the industry and are also known to include printed circuit boards and other board forms as part of them, some of which include multiple such components depending on their operating requirements. There is also.

  As described herein, the composition of the present invention reduces the dielectric constant, reduces the dielectric loss factor, reduces the cure shrinkage, reduces the coefficient of thermal expansion (CTE), and is good. An insulating layer of a circuit board exhibiting thermal conductivity is provided.

  The present invention comprises an insulating composition made for the circuit board, and the insulating composition comprises a two-component fluorinated polymer substrate and at least two inorganic filler materials (hereinafter referred to as filler). It is characterized by. This substrate consists of two fluoropolymers, each having a different melting point, one being the “high melting point” and the other the “low melting point”. As used herein, the term “high melting point” means a melting point in the range of about 300 ° C. to about 350 ° C., and the term “low melting point” means about 200 ° C. to 280 ° C. Means the melting point in the range of Examples will be given later.

  Furthermore, it should be noted that the inorganic fillers have different thermal conductivities, one being said to have “high thermal conductivity” and the other having “low thermal conductivity”. It is said that As used herein, the term “high” means a thermal conductivity in the range of about 600 W / mK to about 2000 W / mK, and the term “low thermal conductivity” is about 5 W / mK to 400 W. It means a thermal conductivity in the range of / mK. Such material combinations with such properties ensure that the resulting insulating layer has a low dielectric constant (eg, about 2.8 to about 3.6) and a low coefficient of thermal expansion (eg, about 15 ppm / ° C. to about 79 ppm / ° C) and low heat dissipation rate. As will be understood from the following examples, such a composition is relatively easy to process and use as an insulating material for circuit boards. Of note, the ratio of the high melting point fluoropolymer to the low melting point fluoropolymer can be adjusted for relatively significant changes in the melting point of the final product, resulting in a class of melting point configuration. On the other hand, it can significantly improve production. Furthermore, the composition can be sintered at a relatively lower temperature than is known in many of the conventionally used fluoropolymer compositions. The filler itself consists of relatively small particles, less than about 10 microns, preferably 3-5 microns, which have a good monodispersity to aid laser drilling when high density circuits are required. ing. In addition, the composition can be easily drilled (mechanically or with a laser) or punched to form the required number of conductive through holes, including a plurality of insulating and conductive layers. This is a particularly preferred feature when bonding substrates to form larger (thicker) multilayer structures having The use of a laser to “drill” such through holes is particularly desirable in view of the ability to form a large number of such holes at a relatively high density. All these features and other features found herein are highly desirable in circuit board technology.

  The compositions described herein can be formed as a single layer (without a support structure) or in a combined layer with such a support structure, the best known of such structures being Conventionally, a glass fiber cloth used with various resins in the printed circuit board industry. In the latter case, the composition is coated onto a fabric support and layer formed as a single piece. The layer formed using the composition alone or in combination with the support structure has a thickness in the range of about 0.5 mils (thousandths of an inch) to about 5 mils. Can do.

The composition of the present invention contains at least the above-mentioned two inorganic fillers, each of which includes silica, alumina, alumina, aluminum nitride, silicon nitride, silicon carbide, boron nitride, diamond powder, titanium oxide, ceramic and the like. Each filler is naturally selected to have a thermal conductivity defined in relation to the other. In one example, these fillers are composed of spherical crystals or amorphous silica and constitute about 10-60% by weight of the final composition. One suitable example of such silica is sold by Tatsumori Co., Ltd. (represented by Tatsumori USA, New York, NY) located in 2-9-3 Shiba Park, Minato-ku, Tokyo. "PLV-6" having an average particle size of about 5.2 microns. Another example is Tatsumori's “PLV-4” silica, which has an average particle size of 3.4 microns.

  Another supplier of silica filler is Asahi Glass S-Tech Co., Ltd. (No. 13-1, Hokutocho, Wakamatsu-ku, Kitakyushu City, Fukuoka Prefecture). Two types of products are used, one with low oil absorption grade with average particle size of 3-20 μm and one with non-porous grade with average particle size of 4-20 μm (NP-100, NP-30) ( NP series). Further sources of spherical silica are Cima Electronics Co., Ltd. (82-chome Hanasaki-cho, Naka-ku, Yokohama-shi, Kanagawa) and Cosem Korea Semiconductor Material (Korea, Korea, 116 Yangji-Ri). Yonmu-Eup, Nonsan City, Chungnam).

  As will be appreciated, each filler may be a combination of two or more of these silicas, resulting in a two or three component composition. Tatsumori's silica has a spherical particle structure. Further fillers that can be used in the present invention are the product series “AE” (alumina) and “SE” (Aluminum) sold by Admatech AB (Datavagen 20, SE-436 32 ASKIM), Sweden. Silica). Examples include Admatech's "SE2300" (average particle size of only 0.4 to 0.6 microns), "SE5300" (average particle size of 1.3 to 2.0 microns), "SE6300" (1.5 -2.5 micron average particle size), "SE4050" (1.5-2.5 micron average particle size), "AE2100" (0.7-1.0 micron average particle size), and "{ AE9100 "(5.0-7.0 micron average particle size). In one embodiment of the present invention, it is desirable to include both fillers in a ratio of low thermal conductivity filler to high thermal conductivity filler in a ratio of about 9: 1 to about 1: 9. Examples include the following: 1) Aerosil 200, a fumed silica available from Degussa AG (Bennigsenplatz 1, D-40474, Dusseldorf), which has an average particle size of 12 nanometers or about 175 to about 225 square meters per gram And a silicon dioxide (silica) content greater than 99.8%. 2) SDT-60 hollow fine particles having an average particle size of 7 μm. 3) Quso G135, a precipitated silica (also available from Degussa). It has about 98% silicon dioxide and a surface area of about 180 square meters per gram and an average aggregate size of 2 microns. Some of such fillers (eg, Quso G135 filler) also act as anti-settling agents.

  Where the filler is silica, it is preferably spherical amorphous silica, and in the percentages described above, this filler provides a determinant of the coefficient of thermal expansion (CTE) for the insulating layer. . This spherical nature of the filler allows for high volume loading of the filler without disturbing the general lamination process by over-extending the melt viscosity of the composition. In one embodiment, about 50% by weight of this particular silica is used. The silica may be in the form of spherical or hemispherical amorphous particles or in the form of hollow silica particulates, or a combination thereof. Silica filler is an important element in this composition because it does not require the use of a fabric (support material), it can be used in low amounts, and has a CTE value for the composition. Can be lower (and more isotropic). The inclusion of such a filler provides an isotropic CTE that gives further reliability to the through hole (particularly plated by conventional metallurgy such as copper or copper alloy), which is another feature of the present invention. The inclusion of two different silicas also improves the electrical properties for the insulating layer that includes supporting glass fibers as part of it, because the elimination of some fabrics with high dielectric constant (Er) values reduces the This is because a composition having a dielectric constant is formed. Adding a particular filler such as one or more silicas as described herein typically increases the brittleness of the insulating layer. However, the combination of the two fluoropolymers ensures that such brittleness of the final layer is reduced to an acceptable level. The above examples of fillers are representative and do not limit the present invention. The micron size of each particle of both inorganic fillers is preferably less than 10 microns as described above, and all the above examples are less than 10 microns.

Fluoropolymers used in accordance with the present invention are well known and include commercially available polyfluoroalkylenes such as polytetrafluoroethylene, copolymers of polytetrafluoroethylene and hexafluoropropylene, and polytetrafluoroethylene. And copolymers of perfluoro 2-2dimethyl 1,3 dioxide, polytrifluorochloroethylene, copolymers of tetrafluoroethylene and olefins (such as ethylene), copolymers of trifluoromonochloroethylene and olefins (such as ethylene), , A polymer of perfluoroalkyl vinyl ether. Some commercially available fluoropolymers used by the present invention are TEFLON PTFE (polymer of polytetrafluoroethylene), TEFLON FEP (per-fluorinated ethylene-propylene copolymer), TEFLON PFA (polytetrafluoroethylene and perfluoro-ethylene). Copolymer of alkoxy), TEFZEL (copolymer of polytetrafluoroethylene and ethylene), HALAR (copolymer of chlorotrifluoroethylene and ethylene), KEL-F (polymer of chlorotrifluoroethylene), HBF-430 (of chlorotrifluoroethylene) Polymer); and TEFLON AF (a copolymer of polytetrafluoroethylene and at least 65 mol% perfluoro-2,2-dimethyl-1,3 dioxide). Including the ability ones. Teflon is a trademark of EI DuPont de Nemours & Company (DuPont), and Halar is a Solvay Solexis company. S.p.A.).

  As mentioned above, the composition of the present invention contains at least two fluoropolymers (each having a different melting point) as part thereof. More specific examples of the above-mentioned fluoropolymers used in the present invention include trade names “Teflon (registered trademark) PTFE 30”, “304A Teflon (registered trademark) PTFE”, “305A Teflon (registered trademark) PTFE”, and “Teflon (registered trademark). ) PTFE 30B "," Teflon PTFE TE-3823 "and" Teflon PTFE K-20 "sold by DuPont, each of which has a melting point of about 327 ° C. Have PTFE is understood to mean polytetrafluoroethylene. DuPont is located at 1007 Market Street, Wilmington, Delaware, USA. “Teflon® PTFE 30” is a negatively charged lyophobic colloid containing polytetrafluoroethylene resin particles (0.05-0.5 microns) suspended in water. In addition, it contains nonionic wetting agents and stabilizers, has a viscosity of about 20 centipoise at room temperature, and 10 pH. It is known to have prominent dielectric properties that are considered very stable when exposed to vibrations and temperature changes. Another DuPont fluoropolymer suitable for use in the present invention is “Zonyl PTFE TE-3667N”, which has a melting point of about 325 ° C. Zonyl is also a trademark of DuPont. This fluoro additive is also a negatively charged lyophobic colloid with resin particles of similar size as “Teflon® PTFE 30” material, with comparable viscosity and pH value . It has a low molecular weight. Further, DuPont fluoropolymers useful in the present invention include “Teflon® PFA 335” having a melting point of about 305 ° C. and “121A Teflon® FEP” having a melting point of 260 ° C. Another fluoropolymer that can be used in the present invention is the trade name “Hala ECTFE” sold by Solvay Solexis, Inc., described above (located in Via Lombardia 20, 1-20021 Bollate, MI, Italy). It is. This product is a copolymer of ethylene and chlorotrifluoroethylene and has a melting point of about 240 ° C. It is a partially fluorinated semicrystalline polymer with high purity. As yet another example of a suitable fluoropolymer, a product sold under the trade name “Fluon LM-ETFE” is permitted. The fluoropolymer is a melt processable copolymer of ethylene and polytetrafluoroethylene having a melting point of about 225-260 ° C. Fullon is a trademark of Asahi Glass Co., Ltd. (ACG) located in 1-12-1, Yurakucho, Chiyoda-ku, Tokyo. In one embodiment of the present invention, the ratio of higher ("high") melting point fluoropolymer to lower ("low") melting point fluoropolymer is in the range of about 9: 1 to about 1: 9. Both fluoropolymers comprise about 50% to about 90% by weight of the composition.

  Further, if desired, the filler can be coated with about 0.2 to about 2.0% (typically about 1%) silane of the filler to provide more hydrophilic properties. Common silanes include p-chloromethyl phenyl trimethoxy silane, aminoethyl amino trimethoxy silane, aminoethyl amino propyl trimethoxy silane.

  The compositions of the present invention preferably further comprise a coupling agent, with silane being preferred, which constitutes only about 0.50 weight percent of the composition. Suitable silanes are tridecafluoro-1,1,2,2-tetrahydro sold by United Technologies, Inc. (2731 Bartram Road, Bristol, PA 19007-6893, USA). It is a fluoro silane named octyl-1-triethoxysilane. Further silanes that can be used in the present invention are phenyl trimethoxy silane and tridecafluoro-1,1,2,2-tetrahydrooctyl-1-trichlorosilane. The coupling agent used in the present invention promotes the chemical bonding between the silica filler and the resin, and further improves the adhesion between the insulating material and the conductive layer used in the circuit board, and further improves the composite material layer. It functions to give high alkali resistance. Silane is used to treat the silica particles directly before being incorporated into the composition.

  It is important to the success of the present invention that the amount of the two-component fluoropolymer system used is equal to or greater than the amount of the composite filler system, preferably the composition comprises about 50 to about 90% by weight. Most preferably from about 50 to about 70% by weight of fluoropolymer, correspondingly containing from about 10 to about 50% by weight filler, preferably from about 30 to about 50% by weight. . These amounts are based on the sum of filler and fluorinated polymer material in the dry composition.

  It is recommended that the compositions of the present invention contain surfactants (eg, nonionic active agents and anti-settling agents). Such surfactants are typically used in an amount of about 0.1 to about 10%, preferably about 0.5 to about 6% by weight of the total composition. In fact, commercially available fluorinated polymer formulations contain a surfactant. It is also recommended that the pH of the composition should be about 8 to about 11, more preferably about 9 to 10 to facilitate processing. The pH can be controlled by adding a suitable base (eg ammonium hydroxide).

  The composition of the present invention can be produced by mixing an aqueous dispersion of a fluoropolymer material with high speed stirring (eg, high speed dispersion at about 3000 to about 5000 revolutions per minute for about 10 to about 15 minutes). it can. If the filler dispersion is prepared just before use, it can be stirred at a relatively low speed of about 100 rpm. The filler dispersion should then be high speed agitation (eg, high speed dispersion at about 3000 to about 5000 rpm for about 10 to about 15 minutes). The high-speed disperser disperses a filler composed of at least one of silica and quartz to make the particles non-aggregated.

  This composition is then coated onto a suitable substrate. This can be done as a single sheet on the substrate or as a continuous coating on a web-type substrate. The coating is made at a desired thickness of about 0.2 mils or greater (usually about 0.5 mils, preferably about 0.5 to about 3 mils thick).

  After coating the desired composition to the desired thickness on the substrate, the coating removes the surfactant when it is at a temperature of about 240 ° C to about 320 ° C (preferably about 300 ° C to about 320 ° C). To be baked. The layer is then melted at a temperature of about 260 ° C to about 400 ° C (preferably about 260 ° C to about 380 ° C). Prior to removal of the surfactant, water can be removed from the composition, if desired, by heating at about 110 ° C. for about 20 to about 60 minutes. Heating to remove the surfactant is from about 0.30 hours to about 2 hours (preferably about 1.5 hours). The heating that causes melting or densification of the composition is usually about 30 to about 120 minutes, and is generally done under a pressure of about 1000 to about 3000 PSI (preferably about 1200 to about 1800 PSI).

  At this point, the substrate, optionally coated, can be removed by etching, for example, to form a stand-alone film of fluorinated polymer material and filler. A typical substrate used in the process includes a copper / invar / copper (CIC) composite. Such substrates are generally about 0.7 to about 40 mils thick and preferably about 0.7 to about 3 mils thick. If copper or a copper composite is used, such a substrate can be removed from the fluoropolymer composite by etching with a typical copper etchant (eg, cupric chloride).

  Suitable surfactants that can be used include nonionic surfactants. A suitable surfactant is octyl phenoxyethanol, which is available from Rohm & Haas (USA, 100 Independence Mall West, Philadelphia, PA) under the trade name Triton X-100.

  The composition produced according to the present invention can be perforated or stamped to form the desired vias in the substrate. Laser drilling is performed with the coating directed at the laser, preferably between about 3 and about 30 joules / cm 2 (at 308 nanometers), typically using a noble gas halide laser such as xenon chloride. Various lasers with UV to IR wavelengths of 308 nanometers with a fluence of Joules / cm are used. Laser drilling may be either contact type or projection type. In order to form vias in a given area, a laser resistant coating such as copper or copper / invar / copper is applied to the areas where no holes are formed on the substrate.

  However, when a fabric is used as the substrate, the amount of composition applied to the fabric depends on the desired final thickness of the pressed (eg, laminated) insulating layer. It should be noted that the inclusion of silica filler as disclosed herein allows the use of thinner and lighter styles of woven glass fabric while still achieving the desired thickness, and the circuit board. Maintain or improve dimensional changes in both the xy plane and the vertical plane. The combination of silica filler and thinner and lighter woven fabric also improves the laser perforation of the insulating layer by increasing the organic / inorganic homogeneity of the material (to provide the through holes described above). The insulation resistance reliability of the laminate is also improved by reducing the fiberglass in contact with the conductive material. Of further note, in addition to the other beneficial effects described above, the presence of silica filler improves copper plating adhesion, improves crack resistance, and further improves plating through-hole reliability. To do.

The glass woven fabric may be dipped into the composition material, dried, sintered, and then laminated to other layers desired to be used as part of the finished circuit board. As a result, a circuit board with several very beneficial features described herein is formed. One example of key electrical, thermal, physical, and thermal expansion properties obtained using the compositions of the accompanying examples is shown in Table 1 below. In general, insulating layers made using the teachings of the present invention have a dielectric constant in the range of about 2.45 to about 3.6 and a loss factor in the range of about 0.0008 to about 0.003 at 1 MHz. And may have a decomposition temperature in the range of about 400 ° C to about 500 ° C.

(Example 1)
About 112 grams of polytetrafluoroethylene (PTFE) aqueous dispersion TEFLON PTFE TE-382 (containing 60% (total weight ratio) of 0.05 to 0.5 micron PTFE resin particles) With a non-ionic wetting agent that burns off at about 50 ° C. below) and about 224 grams of Teflon PFA 335 (0.05-0 suspended in water). Composition containing 60% (total weight ratio) of 5 micron perfluoroalkoxy (PFA) resin particles), 220 grams of OLV-6 silica (Dragon) having an average particle size of about 5.2 microns. Available from the forest) and mixed at about 2000 to about 5000 RPM for about 15 to 25 minutes under high agitation in a high speed disperser and allowed to equilibrate for about 1 to about 2 hours . This composition was then coated from an aqueous dispersion onto a copper substrate to a thickness of about 2.6 mils using techniques well known in the coating art. The coating is then superheated at a temperature of about 100 ° C. to about 115 ° C. to remove water, followed by heating at about 240 ° C. to about 260 ° C. for 1 hour to remove the surfactant and sintering. It was peeled off from the belt or in this case the stand-alone sheet and the composition was pressed at about 300 ° C. to 350 ° C. for about 65 minutes under a pressure of about 1600 PSI to about 2000 PSI. The copper of the substrate is then removed by etching with cupric chloride to obtain a high quality free standing film. The dried composite after dissolution has a coefficient of thermal expansion (CTE) in the range of about 14 ppm / ° C. to about 28 ppm / ° C., a dielectric constant of about 2.68, and a composite density of about 2.16 g / cc.

(Example 2)
About 134.4 grams of polytetrafluoroethylene (PTFE) aqueous dispersion TEFLON PTFE 30B (containing 60% (based on total weight) of particles having the particle size of Example 1 above), and about 201.6 grams of Suspension containing Teflon PFA 335 (containing 60% (based on total weight) of 0.05-0.5 micron perfluoroalkoxy (PFA) resin particles suspended in water) The liquid is mixed with 187 grams of Tatsumori PLV-3 silica having an average particle size of about 2.8 microns at about 2000 to about 5000 RPM for about 15-25 minutes under high agitation in a high speed disperser and about 30 minutes It was possible to equilibrate for ~ 2 hours. This composition was then coated from an aqueous dispersion onto a copper substrate to a thickness of about 2.5 mils. The coating is then heated at a temperature of about 100 ° C. to about 115 ° C. to remove water, followed by heating at about 240 ° C. to 260 ° C. for 1 hour to volatilize and sinter the surfactant, and It was then pressed at a temperature of about 310 ° C. to about 350 ° C. for about 65 minutes under a pressure of about 1600 PSI to 2000 PSI. The resulting film thickness is about 1.6 to 1.9 mils. The copper is removed by cupric chloride etching and dried to have a coefficient of thermal expansion (CTE) in the range of about 16.2 ppm / ° C. to about 28 ppm / ° C., a dielectric constant of about 2.48, and about 2 A film having a composite density of .15 g / cc is obtained.

Example 3
About 63.8 grams of polytetrafluoroethylene (PTFE) aqueous dispersion TEFLON PTFE TE-3823 (containing 60% (total weight ratio) of 0.05 to 0.5 micron PTFE resin particles) About 225 grams of Teflon consisting of 0.1 to 0.3 micron fluorinated ethylene propylene (FEP) resin particles (compounded with non-ionic wetting that burns at about 50 ° C. below the active agent) A binary fluoropolymer suspension containing ® FEP 121A (54% total weight ratio) was mixed with 154 grams of Tatsumori PLV-4 silica having an average particle size of 3.8 microns. This suspension was then coated on a copper substrate at a thickness of about 2.2 mils, which was then heated at a temperature of about 100 ° C. to about 115 ° C. to produce water. Removed and subsequently heated at about 240 ° C. to 260 ° C. for 1 hour to volatilize and sinter the surfactant, and then about 265 ° C. to about 350 ° C. for about 65 minutes under a pressure of about 1600 PSI to 2000 PSI. Pressed at a temperature of 0 ° C. The thickness of the obtained film is about 1.3 to 1.6 mil, and this copper is removed by etching with cupric chloride to obtain a free standing film. This dry composite has a coefficient of thermal expansion (CTE) in the range of about 22.5 ppm / ° C. to about 30 ppm / ° C., a dielectric constant of about 2.45, and a composite density of about 2.15 g / cc. .

Example 4
About 29 grams of polytetrafluoroethylene (PTFE) aqueous dispersion TEFLON PTFE TE-3823 (containing 60% (total weight ratio) of 0.05 to 0.5 micron PTFE resin particles) About 34.8 grams of Teflon PFA 335 (0.05-0.5 micron perfluoro-suspension suspended in water). 60% (total weight ratio) of alkoxy (PFA) resin particles) and about 225 grams of Teflon FEP 121A (0.1-0.3 micron fluorine suspended in water). A three-component fluoropolymer composition containing 54% (total weight ratio) of ethylene propylene (FEP) resin particles) is a trade name of AO-900H 164 grams of spherical alumina with an average particle size of 2-8 microns available from Admatetechs Vo. Ltd., mixed with a high speed disperser at about 2000-5000 RPM for about 15-25 minutes, Equilibrated for 2 hours. This suspension was then coated on a copper substrate at a thickness of about 2.2 mils. The coating is then heated at a temperature of about 100 ° C. to about 115 ° C. to remove water, followed by heating at about 240 ° C. to 260 ° C. for 1 hour to volatilize and sinter the surfactant, and It was then pressed at a temperature of about 265 ° C. to about 350 ° C. for about 65 minutes under a pressure of about 1600 PSI to 2000 PSI. The resulting film thickness is about 1.3-1.6 mils. This dried composite after dissolution has a coefficient of thermal expansion (CTE) in the range of about 42 ppm / ° C. to about 53 ppm / ° C., a dielectric constant of about 2.97, and a composite density of about 2.54 g / cc. .

  It should be noted that Example 4 includes adding a third fluoropolymer to the composition, which means that the present invention is not limited to using only two fluoropolymers. To do. Of further note, these fluoropolymers have different melting points. For example, the fluoropolymer of Example 4 has a melting point of about 327 ° C. to about 335 ° C. (PTFE), about 305 ° C. (PFA), and about 260 ° C. (FEP). Further examples of such three fluoropolymer compositions are described in Examples 5 and 7 below.

(Example 5)
About 48 grams of polytetrafluoroethylene (PTFE) aqueous dispersion TEFLON PTFE TE-3823 (containing 60% (total weight ratio) of PTFE resin particles of 0.05 to 0.5 microns) About 52 grams of Teflon PFA 335 (0.05-0.5 micron perfluoroalkoxy (suspended in water)). PFA) resin particles 60% (total weight ratio)) and about 196 grams of Teflon® FEP 121A (0.1-0.3 micron fluorinated ethylene suspended in water) 3 component fluoropolymer composition containing 54% (total weight ratio) of propylene (FEP) resin particles), based on the conditions of Example 4, SP-4 Mixed and 147 grams of spherical silica having an average particle size of 4 microns, available from Fuso Chemical Co., Ltd. under the name. This composition is processed under the same conditions as in Example 4 to form a dry film having a thickness of about 1.3 to 1.6 mils. The dry film has a coefficient of thermal expansion (CTE) in the range of about 26 ppm / ° C. to about 33 ppm / ° C., a dielectric constant of about 2.44, and a composite density of about 2.14 g / cc.

(Example 6)
About 56 grams of polytetrafluoroethylene (PTFE) aqueous dispersion TEFLON PTFE TE-3823 (containing 60% (total weight ratio) of 0.05 to 0.5 micron PTFE resin particles) About 64 grams of Teflon® FEP 121A (0.1 to 0.3 micron suspended in water). A two-component fluoropolymer composition containing 54% (total weight ratio) of fluorinated ethylene propylene (FEP) resin particles) is available from Tatsumori under the name PLV-4. 154 grams of spherical silica with an average particle size of microns and available from Admatechs Vo. Ltd. under the trade name AO-509. And 46 g of spherical alumina, at a high speed disperser, are mixed at about 1500~5000RPM about 15-25 minutes, it is 1 to about 2 hours equilibration. This composition was then coated from an aqueous dispersion onto a copper substrate at a thickness of about 2.2 mils. The coating is then heated at a temperature of about 100 ° C. to about 115 ° C. to remove water, followed by heating at about 240 ° C. to 260 ° C. for 1 hour to volatilize and sinter the surfactant, and It was then pressed at a temperature of about 265 ° C. to about 350 ° C. for about 65 minutes under a pressure of about 1600 PSI to 2000 PSI. The thickness of the film obtained after this copper has been removed by etching is about 1.3 to 1.6 mils. This dried composite after dissolution has a coefficient of thermal expansion (CTE) in the range of about 52 ppm / ° C. to about 70 ppm / ° C., a dielectric constant of about 2.54, and a composite density of about 2.30 g / cc. .

(Example 7)
About 35 grams of polytetrafluoroethylene (PTFE) aqueous dispersion TEFLON PTFE TE-3823 (containing 60% (total weight ratio) of 0.05 to 0.5 micron PTFE resin particles) About 46 grams of Teflon PFA 335 (0.05-0.5 micron perfluoroalkoxy (suspended in water)). PFA) resin particles (containing 60% (total weight ratio)) and about 76 grams of Teflon FEP 121A (0.1-0.3 micron ethylene fluoride suspended in water) The composition containing 54% (total weight ratio) of propylene (FEP) resin particles) was entered from Tatsumori under the name PLV-3 based on the conditions of Example 6. Mixed 29.8 grams of spherical alumina available from Admatechs under the name 58.5 g of spherical silica and AO-900 having an average particle size of 3.8 microns as possible. This composition was then coated on a support substrate such as copper and processed based on the conditions used in Example 6. The resulting film thickness is about 1.3-1.6 mils. After the copper is removed by etching with cupric chloride, the dry composite film has a coefficient of thermal expansion (CTE) in the range of about 36 ppm / ° C. to about 54 ppm / ° C. and a composite of about 2.23 g / cc. Has a density.

  As will be further understood by the description herein, the particular application of the circuit board formed in the present invention is a chip carrier or printed circuit board or other electronic such as manufactured and sold by the assignee of the present invention. As part of a component mounting (electronic packaging) product. One particular example is a chip carrier sold under the trade name Hyper-BGA chip carrier (Hyper-BGA is a registered trademark of Endicott Interconnect Technologies).

  Of course, the present invention is not limited to chip carriers or high-level printed circuit boards. Such a circuit board (also referred to as a “core”, for example, a core is provided with one or more power layers, and thus is primarily referred to as a “power core” when it performs this function) is optional for the final product. Depending on the requirements of such a carrier or printed circuit board. As defined below, the “core” is easily “stacked up” on other layers (including conductive or insulating layers) and joined together (preferably conventional printed circuit board lamination techniques). A multilayer carrier or a multilayer printed circuit board can be formed.

  The laminate thus formed is then further processed, including a conventional photolithography process that forms a circuit pattern on its outer conductive layer. As will be described below, such external patterns may include conductive pads on which the structure can be placed on other elements (eg, semiconductor chips, printed circuits) if desired. A conductor such as a solder ball may be placed for connection to the substrate and chip carrier. Therefore, the unique teaching of the present invention can be applied to various electronic component mounting products.

  While what has been considered presently the preferred embodiment of the invention has been described with reference to the drawings, various changes and modifications may be practiced without departing from the scope of the invention as set forth in the appended claims. It will be apparent to those skilled in the art that it can be done in

Claims (23)

An insulating composition that can be used in a circuit board,
A first fluoropolymer having a first melting point and a second fluoropolymer having a second melting point lower than the first melting point;
A first inorganic filler having a first thermal conductivity, and a second inorganic filler having a thermal conductivity lower than the first thermal conductivity;
Insulating composition characterized by including. The insulating composition of claim 1, wherein the first and second inorganic fillers include particles having a size of about 10 microns or less. The insulating composition according to claim 2, wherein the particles have a spherical shape. The first and second inorganic fillers are selected from the group consisting of alumina, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, boron nitride, diamond powder, titanium oxide, silica, ceramic and combinations thereof. The insulating composition according to claim 2. The first and second inorganic fillers are silica, and the silica is selected from the group consisting of spherical amorphous silica, hemispherical amorphous silica, hollow silica fine particles, and combinations thereof. The insulating composition according to claim 4. The first and second fluoropolymers are attributed to the polytetrafluoroethylene system and comprise about 50 to 90 weight percent of the composition, and the first and second fillers are The insulating composition of claim 1 comprising about 10 to 50 weight percent of the composition. The insulating composition according to claim 1, further comprising a support member, wherein the insulating composition and the support member are combined to form an insulating layer that can be used in the circuit board. object. The insulating composition according to claim 7, wherein the support member is made of a glass fiber cloth. The first melting point is in the range of about 300 degrees Celsius to about 350 degrees Celsius, and the second melting point is in the range of about 200 degrees Celsius to about 280 degrees Celsius. The insulating composition according to claim 1. The first thermal conductivity is in the range of about 600 W / mK to about 2000 W / mK, and the second thermal conductivity is in the range of about 5 W / mK to about 400 W / mK. The insulating composition according to claim 9. The third fluoropolymer of claim 1, further comprising a third fluoropolymer having a melting point lower than the first melting point of the first fluoropolymer and the second melting point of the second fluoropolymer. Insulating composition. A circuit board,
A first fluoropolymer having a first melting point, a second fluoropolymer having a second melting point lower than the first melting point, and a first inorganic filler having a first thermal conductivity and At least one insulating layer having an insulating composition comprising a second inorganic filler having a thermal conductivity lower than the first thermal conductivity;
At least one conductive layer disposed on the at least one insulating layer;
A circuit board comprising: The circuit board according to claim 12, wherein the at least one conductive layer is made of copper or a copper alloy. 13. The circuit board according to claim 12, wherein the first and second inorganic fillers include particles having a size of about 10 microns or less. The circuit board according to claim 14, wherein the particles have a spherical shape. The first and second inorganic fillers are selected from the group consisting of alumina, aluminum oxide, aluminum nitride, silicon nitride, silicon carbide, boron nitride, diamond powder, titanium oxide, silica, ceramic and combinations thereof. The circuit board according to claim 14. The first and second inorganic fillers are silica, and the silica is selected from the group consisting of spherical amorphous silica, hemispherical amorphous silica, hollow silica fine particles, and combinations thereof. The circuit board according to claim 16. The first and second fluoropolymers are attributed to the polytetrafluoroethylene system and comprise about 50 to 90 weight percent of the composition, and the first and second fillers are The circuit board of claim 12, comprising about 10 to 50 weight percent of the composition. The circuit board according to claim 12, further comprising a support member, wherein the insulating composition and the support member are combined to form an insulating layer that can be used in the circuit board. The circuit board according to claim 19, wherein the support member is made of a glass fiber cloth. The first melting point is in the range of about 300 degrees Celsius to about 350 degrees Celsius, and the second melting point is in the range of about 200 degrees Celsius to about 280 degrees Celsius. The circuit board according to claim 12. The first thermal conductivity is in the range of about 600 W / mK to about 2000 W / mK, and the second thermal conductivity is in the range of about 5 W / mK to about 400 W / mK. The circuit board according to claim 20. The third fluoropolymer of claim 12, further comprising a third fluoropolymer having a melting point lower than the first melting point of the first fluoropolymer and the second melting point of the second fluoropolymer. Circuit board.