USRE36396E - Electrical substrate material comprising amorphous fused silica powder - Google Patents

Electrical substrate material comprising amorphous fused silica powder Download PDF

Info

Publication number
USRE36396E
USRE36396E US08/379,991 US37999195A USRE36396E US RE36396 E USRE36396 E US RE36396E US 37999195 A US37999195 A US 37999195A US RE36396 E USRE36396 E US RE36396E
Authority
US
United States
Prior art keywords
iaddend
iadd
substrate material
ppm
cte
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US08/379,991
Inventor
David J. Arthur
John C. Mosko
Connie S. Jackson
G. Robert Traut
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
World Properties Inc
Original Assignee
Rogers Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US07/015,191 external-priority patent/US4849284A/en
Application filed by Rogers Corp filed Critical Rogers Corp
Priority to US08/379,991 priority Critical patent/USRE36396E/en
Assigned to WORLD PROPERTIES, INC. reassignment WORLD PROPERTIES, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ROGERS CORPORATION
Application granted granted Critical
Publication of USRE36396E publication Critical patent/USRE36396E/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00Details of semiconductor or other solid state devices
    • H01L23/12Mountings, e.g. non-detachable insulating substrates
    • H01L23/14Mountings, e.g. non-detachable insulating substrates characterised by the material or its electrical properties
    • H01L23/145Organic substrates, e.g. plastic
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/18Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
    • H01B3/30Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
    • H01B3/44Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins
    • H01B3/443Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins from vinylhalogenides or other halogenoethylenic compounds
    • H01B3/445Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes vinyl resins; acrylic resins from vinylhalogenides or other halogenoethylenic compounds from vinylfluorides or other fluoroethylenic compounds
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/03Use of materials for the substrate
    • H05K1/0313Organic insulating material
    • H05K1/0353Organic insulating material consisting of two or more materials, e.g. two or more polymers, polymer + filler, + reinforcement
    • H05K1/0373Organic insulating material consisting of two or more materials, e.g. two or more polymers, polymer + filler, + reinforcement containing additives, e.g. fillers
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001Technical content checked by a classifier
    • H01L2924/0002Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/03Use of materials for the substrate
    • H05K1/0313Organic insulating material
    • H05K1/032Organic insulating material consisting of one material
    • H05K1/034Organic insulating material consisting of one material containing halogen
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/03Use of materials for the substrate
    • H05K1/0313Organic insulating material
    • H05K1/0353Organic insulating material consisting of two or more materials, e.g. two or more polymers, polymer + filler, + reinforcement
    • H05K1/0366Organic insulating material consisting of two or more materials, e.g. two or more polymers, polymer + filler, + reinforcement reinforced, e.g. by fibres, fabrics
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/01Dielectrics
    • H05K2201/0137Materials
    • H05K2201/015Fluoropolymer, e.g. polytetrafluoroethylene [PTFE]
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/01Dielectrics
    • H05K2201/0183Dielectric layers
    • H05K2201/0195Dielectric or adhesive layers comprising a plurality of layers, e.g. in a multilayer structure
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/02Fillers; Particles; Fibers; Reinforcement materials
    • H05K2201/0203Fillers and particles
    • H05K2201/0206Materials
    • H05K2201/0209Inorganic, non-metallic particles
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/02Fillers; Particles; Fibers; Reinforcement materials
    • H05K2201/0203Fillers and particles
    • H05K2201/0206Materials
    • H05K2201/0239Coupling agent for particles
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/02Fillers; Particles; Fibers; Reinforcement materials
    • H05K2201/0203Fillers and particles
    • H05K2201/0242Shape of an individual particle
    • H05K2201/0251Non-conductive microfibers
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/06Thermal details
    • H05K2201/068Thermal details wherein the coefficient of thermal expansion is important
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00Apparatus or processes for manufacturing printed circuits
    • H05K3/46Manufacturing multilayer circuits
    • H05K3/4611Manufacturing multilayer circuits by laminating two or more circuit boards
    • H05K3/4626Manufacturing multilayer circuits by laminating two or more circuit boards characterised by the insulating layers or materials
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/25Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
    • Y10T428/252Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/25Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
    • Y10T428/259Silicic material
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/29Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2982Particulate matter [e.g., sphere, flake, etc.]
    • Y10T428/2991Coated
    • Y10T428/2993Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]
    • Y10T428/2995Silane, siloxane or silicone coating
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/31504Composite [nonstructural laminate]
    • Y10T428/3154Of fluorinated addition polymer from unsaturated monomers
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/31504Composite [nonstructural laminate]
    • Y10T428/3154Of fluorinated addition polymer from unsaturated monomers
    • Y10T428/31544Addition polymer is perhalogenated
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/31504Composite [nonstructural laminate]
    • Y10T428/31678Of metal
    • Y10T428/31692Next to addition polymer from unsaturated monomers

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Laminated Bodies (AREA)

Abstract

A ceramic filled fluoropolymer-based electrical substrate material well suited for forming rigid printed wiring board substrate materials and integrated circuit chip carriers is presented which exhibits improved electrical performance over other printed wiring board materials and circuit chip carriers. Also, the low coefficients of thermal expansion and compliant nature of this electrical substrate material results in improved surface mount reliability and plated through-hole reliability. The electrical substrate material preferably comprises polytetrafluoroethylene filled with silica along with a small amount of microfiberglass. In an important feature of this invention, the ceramic filler (silica) is coated with a silane coating material which renders the surface of the ceramic hydrophobic and provides improved tensile strength, peel strength and dimensional stability.

Description

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an electrical substrate material particularly useful as a circuit or wiring board substrate material and the printed wiring boards formed therefrom; and as an improved packaging system for integrated circuit chips. More particularly, this invention relates to a new and improved printed wiring board substrate comprised of a ceramic filled, microfiberglass reinforced fluoropolymer composite material which exhibits improved electrical performance over other printed wiring board substrate materials; and exhibits low coefficients of thermal expansion and relatively high compliance resulting in improved surface mount and plated through-hole reliability. The high degree of compliance of such a highly filled composite is an unexpected result. The ceramic filler is coated with a material (preferably silane) which renders the surface of the ceramic hydrophobic as well as providing other important and unexpected features. This ceramic filled, microfiberglass reinforced fluoropolymer composite material is also well suited for use in an improved packaging system for integrated circuit chips.
2. Description of the Prior Art
The performance of high speed computers is becoming increasingly limited by current methods of interconnection, from the printed wiring board (PWB) level on up. As ECL or GaAs logic devices are developed with high operating frequencies and shorter rise-times, the PWB substrate, particularly the material comprising the substrates, becomes an important component of circuit design, and substrate material selection is critical. Presently, two major issues for substrate selection are: (1) electrical performance; and (2) surface mount reliability.
For improved electrical performance, and lower dielectric constant, lower loss PWB materials are required, with these properties being stable over wide frequency and temperature ranges. PWB substrate materials currently used which provide reliable electrical performance for high speed applications include fluoropolymer (PTFE) glass composite materials.
In order to use surface mount technology reliably, a close match of the coefficients of thermal expansion (CTE) of the electronic package and the PWB substrate is required to reduce stress on solder joints. However, since the package and the board usually heat up at different rates, a close CTE-match may not be enough. A compliant (low modulus) substrate minimizes the stress on the solder joint resulting from differential strain between the package and the board. Such substrate materials demonstrating favorable coefficients of thermal expansion in the X-Y plane include polyimide/quartz and polyimide/KEVLAR composite materials.
However, no prior art approach has successfully provided a PWB substrate which has effective electrical performance as well as surface mount reliability. While PTFE/glass composites have excellent electrical properties, these materials have poor dimensional stability leading to poor surface mount reliability. Conversely, while polyimide/quartz and polyimide/KEVLAR have excellent surface mount reliability characteristics these materials have relatively high dielectric constant and high loss (or dissipation factor) leading to poor electrical performance. In addition, no prior art approach has a Z-direction thermal expansion coefficient that is sufficiently close to that of copper so that high reliability plated through hole interconnections are achieved.
It will be appreciated that similar requirements (i.e., improved electrical performance and surface mount reliability) exist for surface mounted IC chip carrier packages as well as PWB substrates. Presently available chip carriers are generally comprised of ceramic materials or polymeric materials. Each of these materials have several known disadvantages in terms of electrical properties, environmental resistance, cost and size limitations and/or surface mount reliability.
U.S. Pat. No. 4,335,180, assigned to the assignee hereof, all of the contents of which are incorporated herein by reference, discloses an electrical substrate material which has both improved electrical properties and surface mount reliability. This material is described as a microwave circuit board comprised of a glass reinforced fluoropolymer filled with a ceramic. While suitable for its intended purposes, the microwave material of U.S. Pat. No. 4,335,180 suffers from an important deficiency in that the material exhibits a high degree of water absorption (i.e., the material is hydrophilic). As a result, moisture is absorbed into the microwave circuit leading to undesirable changes in the electrical and other properties of the circuit. Also, this material suffers from other drawbacks including low strength, poor copper adhesion and poor dimensional stability.
SUMMARY OF THE INVENTION
The above-discussed and other disadvantages and deficiencies of the prior art are overcome or alleviated by the electric substrate material of the present invention which provides improved PWB substrates and PWB constructions based upon said substrate: as well as providing improved integrated circuit chip carrier packages.
In accordance with the present invention, a PWB substrate material exhibiting improved electrical performance and excellent thermal expansion and compliancy properties comprises a ceramic filled fluoropolymer wherein the substrate material has the following properties:
(1) low dielectric constant,
(2) low loss;
(3) low thermal expansion, and
(4) chemically inert.
Preferably, the ceramic filler material comprises an amorphous fused silica (SiO2) powder. Also, in a preferred embodiment, the ceramic filled fluoropolymer includes a small degree of glass microfiber reinforcement.
A critical feature of the present invention is that the ceramic filler is coated with a silane coating material which renders the surface of the ceramic hydrophobic thereby precluding undesirable water absorbtion into the PWB substrate. The silane coatings also contribute unexpected improvements to substrate/copper adhesion, strength and dimensional stability. These results were not expected since the silane coating does not chemically bond to the fluoropolymer matrix.
The coated ceramic, reinforced fluoropolymer of the present invention offers a low dielectric constant, for low signal propagation delay; low crosstalk and reduced board thickness: low loss at high frequencies, providing significant reduction in rise-time degradation; excellent control of dielectric constant and thickness, vital for impedance control; and improved thermal conductivity for better heat dissipation. The fluoropolymer based PWB substrate of the present invention also exhibits low CTE in the X-Y plane and the material's inherent compliancy and dimensional stability make it suitable for surface mount applications: while its low CTE in the Z direction yields excellent plated-through-hole reliability. These excellent electrical and thermal expansion characteristics make is suitable for high speed digital and microwave applications requiring surface mounted devices and/or multilayer constructions.
A surface mountable IC chip carrier package comprised of the ceramic filled fluoropolymer composite described above will also exhibit improved electrical and surface mounting properties. In fact, the fluoropolymer composite chip carrier of the present invention may be compounded so as to match the thermal expansion of the printed circuit board thereby minimizing the thermal mismatch between the chip carrier and the PWB. The matching of thermal expansion is easier to achieve when the chip carrier of the present invention is used in conjunction with the PWB substrate of the present invention as the composition thereof will be identical or substantially identical. Also, and just as important, the chip carrier in accordance with the present invention provides many advantages so far as electrical characteristics thereof are concerned. The fluoropolymer composite chip carriers of the present invention are characterized by very low dielectric constant and dissipation factors when compared to prior art ceramic, epoxy or polyimide based chip carriers.
Finally, the silane coated ceramic filled fluoropolymer of the present invention may be utilized as a bonding ply or adhesive layer for bonding together circuit layers in a multilayer circuit board.
The above-discussed and other features and advantages of the present invention will be apparent to and understood by those skilled in the art from the following detailed description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawing wherein like elements are numbered alike in the several FIGURES:
FIG. 1 is a plan view of a printed wiring board in accordance with the present invention;
FIG. 2 is a cross-sectional elevation view along the line 2--2 of FIG. 1;
FIG. 3 is a cross-sectional elevation view of a multilayer printed wiring board in accordance with the present invention;
FIG. 4 is a cross-sectional elevation view of a stripline configuration of a printed wiring board in accordance with the present invention;
FIG. 5 is a cross-sectional elevation view of a "dual" stripline configuration of the printed wiring board in accordance with the present invention;
FIG. 6 is an isometric view of a chip carrier package in accordance with the present invention;
FIG. 7 is a graph of X-Y thermal expansion versus filler content;
FIG. 8 is a graph of Z axis thermal expansion versus filler content;
FIG. 9 is a graph of backward crosstalk versus line spacing for a printed wiring board in accordance with the present invention;
FIG. 10 is a graph showing solder joint reliability tests; and
FIG. 11 is a graph of differential strain versus CTE in the Z direction for several PWB materials.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The electrical substrate material of the present invention which is well suited for forming printed wiring board (PWB) substrate materials and integrated circuit chip carriers comprises a fluoropolymeric material filled with a coated ceramic material: the electrical substrate material having a low dielectric constant, low loss, low coefficient of thermal expansion, as well as being chemically inert. A preferred ceramic material which includes all of the above electrical and physical properties is silica (SiO2), preferably amorphous fused silica powder.
An important and critical feature of the present invention is that the ceramic (i.e.. silica) is coated with a material which renders the ceramic surface hydrophobic. It will be appreciated that ceramic material, particularly silica, is normally hydrophilic. It has been found that the ceramic filler used in previously discussed U.S. Pat. No. 4,335,180 leads to the undesired water absorbing properties, low strength, poor copper adhesion and poor dimensional stability of that prior art material. In a preferred embodiment, this coating is a silane material such as P-chloromethyl phenyl trimethoxy silane sold under the tradename "PROSIL 246" by Speciality Chemicals Company; "A40" (chemical composition unknown) also manufactured by Speciality Chemicals Company; amino ethyl amino trimethoxy silane sold under the tradename "DC Z-6020" by Dow Corning Company; and a mixture of phenyl trimethoxy silane (90-95%) and amino ethyl amino propyltrimethoxy silane (5-10%) sold under the tradename "DC X1-6100" also by Dow Corning Company. Of these silane materials, DC X1-6100 has been found to be most preferred. In addition to precluding water absorption, the silane coating also leads to several other unexpected improvements including better adhesion, strength and dimensional stabiility (which will be discussed in more detail hereinafter). It has been found that a preferred silane coating for effecting these important features and advantages is 1% by weight of the filler (ceramic) material.
Preferably, the fluoropolymer used in the present invention is polytetrafluoroethylene (PTFE) although examples of other fluoropolymers include copolymers of fluorinated monomers such as hexa fluoropropene (HFP), tetrafluoroethylene (TFE), and perfluoro alkyl vinyl ether (PAVE). A small amount of microfiberglass (i.e., having a mean diameter on the order of 1 micron) is preferred for improved dimensional stability in the X-Y plane. It has been found that relative weight percentages of the respective component materials which provide the electrical and thermal advantages described below are 33-40 weight percent fluoropolymer; 55-71 weight percent ceramic filler with at least 1 weight percent (based upon the weight percent of the ceramic filler) silane coating and 0-2 weight percent microfiberglass. Also, it is clear from a review of TABLES 1-3 that the present invention is defined by a volume fraction of ceramic filler of about 50% of the total substrate material. A preferred composition for the of the present invention is 34-36% fluoropolymer (PI FE), 62-64% silica filler (SiO2) having a 1% percent coating of silane thereon, and 1% microfiberglass. Additional ceramic (silica) filler (at the expense of PTFE) will result in a lower thermal expansion coefficient, and therefore improved surface mount reliability. However, increased ceramic filler level results in lower cohesive strength and higher dimensional change after etching circuit patterns. Small levels (1%) of microfiberglass seem to improve dimensional stability after etching; increased fiber content presents processing problems when making sheet thicknesses 2.5 mils and lower.
Turning now to FIGS. 1 and 2, a PWB is shown generally at 10. PWB 10 includes substrate 12 comprised of the ceramic filled fluoropolymeric material of the present invention as described above with a plurality of conductive traces 14 formed on substrate 12 using any suitable and well known technique.
In FIG. 3, a multilayer circuit board is shown generally at 16. Multilayer board 16 comprises a plurality of layers of substrate material 18, 20 and 22, all of which are comprised of the ceramic filled fluoropolymeric material of the present invention. Each substrate layer 18, 20 and 22 has a conductive pattern 23, 24, 25 and 26 respectively thereon. Note that a substrate layer having a circuit pattern thereon defines a circuit substrate. Plated through holes 27 and 28 interconnect selected circuit patterns in a known manner.
In accordance with the present invention, separate sheers 29 and 30 of substrate material having the composition discussed above are used as an adhesive or bond ply to laminate individual circuit substrates together. In a preferred method of forming such a laminate, a stack-up of circuit substrates alternated with one or more layers of the bond ply is made. This stack-up is then fusion bonded at a high temperature whereby the entire multilayer assembly is melted and fused into a homogeneous construction with consistent electrical and mechanical properties throughout. Significantly, note that the adhesive bond ply layers 29 and 30 may be used to laminate circuit substrates comprised of materials other than the silane coated ceramic filled fluoropolymer of the present invention. Although, in a preferred embodiment, a multilayer circuit board includes circuit substrates and interleaved bond plys which are all comprised of the electrical substrate material of the present invention.
FIGS. 4 and 5 relate respectively to well known stripline and "dual" stripline configurations of the present invention. Thus, in FIG. 4, the printed wiring board 10 of FIGS. 1 and 2 is sandwiched between a pair of metal ground shields 31 and 31'. It will be appreciated that if only one ground shield 31 is utilized, a conventional microstrip configuration will be provided. FIG. 5 sets forth a derivation of the stripline of FIG. 4. In FIG. 5, conductors 32 and 34 are oriented in either the "X" direction or the "Y" direction defining a "dual" stripline configuration.
The favorable electrical and thermal properties of the electrical substrate material of the present invention make it well suited for use as a chip carrier package such as well known surface mounted leaded and leadless chip carrier and pin grid array (PGA) packages. For example, in FIG. 6, a leadless chip carrier package is shown generally at 34 and includes a plurality of conductive pads 36 about the periphery thereof and a cavity 38 for accepting an integrated circuit. A cover 40, also comprised of the circuit substrate described hereinabove, is provided on the top surface 42 of chip carrier 34.
The process used in manufacturing the electrical substrate material of the present invention is essentially the same as the manufacturing process described in detail in U.S. Pat. No. 4,335,180, which has previously been incorporated herein by reference. The primary difference between the two processes is the additional step in the present invention of coating the ceramic filler particles with a silane coupling agent. Typically, the ceramic filler particles are coated using the following procedure:
Adjust the pH of water to 3.0 by adding formic acid, and add 63 parts of the acidified water to 100 parts silica filler. Vigourously agitate the concentrated slurry in a high shear mixer (such as a Waring blender). When even dispersion of the filler is achieved, add the appropriate quantity of silane dropwise and continue mixing for about 10 minutes. Then the mixture is transferred to a stainless steel container, topped with a perforated cover, and placed in a hot air convection oven set at 120° C. to dry the water from the mixture, form covalent bonds between the silane coupling agent and the filler, and polymerize the silane coating per condensation reaction. Other less important differences between the manufacturing process of the present invention and that described in U.S. Pat. No. 4,335,180 include the following:
(1) Concentration of Cationic Flocculating Agent:
Required amount of flocculant varies with coating level and filler concentration. Typical levels of polyethylene imine flocculant for a composition of 63% SiO2, 1% glass fiber, 36% PTFE, (coating being DC X1-6100):
______________________________________                                    
Silane Coating                                                            
Level       Required Floculant Level                                      
______________________________________                                    
  0%         0.2 parts per 100 parts filler                               
0.25%       0.13 parts per 100 parts filler                               
 0.5%       0.11 parts per 100 parts filler                               
 2.0%       0.10 parts per 100 parts filler                               
______________________________________                                    
(2) Lubricant Level:
Typically dipropylene glycol lubricant is used at a level of 19% weight percent based on total material weight.
(3) Y-Pass Calendering Conditions:
For thin ply production (about 0.0025"), multiple calender passes (up to five) are required through a gap of about 0.001" at roll bending pressure of 1900 psi.
(4) Lamination Cycle:
Typical conditions are; 1700 psi pressure for entire cycle; heat from room temperature to 700° F. at about 3° F./min. hold for 30 minutes, cool at about 1° F./min to 500° F., cool at max rate (about 20° F./min) to room temp.
EXAMPLES
The following non-limiting Examples 1-8 show how filler level, coating level, fiber type and level affect key properties for printed circuit boards. The examples were prepared in accordance with the method described hereinabove. The results outlined in Table 1 show that an optimal cross-section of properties occurs at 63% silica filler having been coated with a DC X1-6100 silane coating. This preferred level results in low porosity, very low water absorption, high copper adhesion, improved strength and better dimensional stability.
As is clearly shown in TABLE 1. the use of a silane coating dramatically decreases water absorption and increases peel strength, tensile strength and dimensional stability. These important features and advantages are both surprising and unexpected. Note that "Ash Content" is the amount of ceramic filler and fiber remaining in the material after combustion of the fluoropolymer.
                                  TABLE 1                                 
__________________________________________________________________________
EXAMPLE    1  2   3  4   5   6   7   8                                    
__________________________________________________________________________
Coating type             DC  DC  DC  DC                                   
                         X16100                                           
                             X16100                                       
                                 X16100                                   
                                     X16100                               
Coating level (%)                                                         
           0  0   0  0   1.0 1.0 1.0 1.0                                  
Filler level (%)                                                          
           71 71  63 63  71  63  71  63                                   
Fiber type Glass                                                          
              Kevlar                                                      
                  Glass                                                   
                     Kevlar                                               
                         Kevlar                                           
                             Kevlar                                       
                                 Glass                                    
                                     Glass                                
Fiber Level (%)                                                           
           1.0                                                            
              1.0 1.0                                                     
                     1.0 1.0 1.0 1.0 1.0                                  
Ash Content (%)                                                           
           10.5                                                           
              68.1                                                        
                  59.9                                                    
                     61.0                                                 
                         69.2                                             
                             60.9                                         
                                 70.5                                     
                                     62.1                                 
Density (g/cm.sup.3)                                                      
           1.777                                                          
              1.840                                                       
                  2.037                                                   
                     2.003                                                
                         1.885                                            
                             2.104                                        
                                 1.925                                    
                                     2.074                                
Porosity (Vol. %)                                                         
           18.1                                                           
              14.7                                                        
                  6.1                                                     
                     7.1 12.6                                             
                             2.4 11.3                                     
                                     4.4                                  
Water Absorption (%)                                                      
           2.758                                                          
              2.018                                                       
                  1.580                                                   
                     1.960                                                
                         0.594                                            
                             0.123                                        
                                 0.773                                    
                                     0.058                                
48 hr. 50° C.                                                      
Peel Strength (lb/inch)                                                   
           1.61                                                           
              1.10                                                        
                  2.00                                                    
                     5.48                                                 
                         5.62                                             
                             5.81                                         
                                 2.58                                     
                                     9.80                                 
Young's Modulus (kpsi)                                                    
           11.95                                                          
              --  24.85                                                   
                     27.40                                                
                         36.20                                            
                             129.50                                       
                                 60.15                                    
                                     66.70                                
Tensile Strength (psi)                                                    
           298                                                            
              --  414                                                     
                     720 818 1695                                         
                                 956 1407                                 
X-Y CTE (0-120° C.)                                                
           12 10  17 15  10  19  11  17                                   
(ppm'C..sup.-1)                                                           
Z-dir CTE (0-120° C.)                                              
           6  7   15 16  15  20  10  23                                   
(ppm'C..sup.-1)                                                           
Dim. Stability, X-dir                                                     
           +  +   +  +   +   -   +   +                                    
(mils/inch)                                                               
           3.986                                                          
              3.417                                                       
                  2.483                                                   
                     2.520                                                
                         2.596                                            
                             0.144                                        
                                 1.884                                    
                                     0.705                                
Dim. Stability Y-dir                                                      
           +  +   +  +   +   -   +   +                                    
(mils/inch)                                                               
           4.121                                                          
              3.527                                                       
                  2.451                                                   
                     2.789                                                
                         2.771                                            
                             0.189                                        
                                 1.995                                    
                                     0.821                                
Dielectric Constant                                                       
           2.64                                                           
              2.75                                                        
                  2.83                                                    
                     2.78                                                 
                         2.76                                             
                             2.91                                         
                                 2.34                                     
                                     2.85                                 
Dissipation Factor                                                        
           .0023                                                          
              .0046                                                       
                  .0026                                                   
                     .0022                                                
                         .0017                                            
                             .0024                                        
                                 .0034                                    
                                     .0016                                
Filter Volume Fraction                                                    
           0.569                                                          
              0.569                                                       
                  0.554                                                   
                     0.554                                                
                         0.593                                            
                             0.581                                        
                                 0.612                                    
                                     0.584                                
(%)                                                                       
__________________________________________________________________________
                                  TABLE 2                                 
__________________________________________________________________________
                                                      Filler Volume       
                WATER                                 Fraction (%)        
                ABSORPTION                            (Assuming X1 =      
     SILANE                                                               
          ASH   24 hr.                                                    
                    48 hr.                                                
                        PEEL  YOUNG'S                                     
                                    TENSILE                               
                                          X-Y CTE,                        
                                                Z-dir CTE                 
                                                      (ASH)/(100) -       
EXAM-                                                                     
     LEVEL                                                                
          CONTENT                                                         
                23° C.                                             
                    50° C.                                         
                        STRENGTH                                          
                              MODULUS                                     
                                    STRENGTH                              
                                          0-120° C.,               
                                                0-120° C.,         
                                                      0.1 where           
PLE  (%)  (%)   (%) (%) (lb/inch)                                         
                              (psi) (psi) (ppm ° C..sup.-1)        
                                                (ppm ° C..sup.-1)  
                                                      ASH = 2.0           
                                                      g/cm.sup.3)         
__________________________________________________________________________
 9   0    60.2  1.777                                                     
                    1.651                                                 
                         5.7   25,000                                     
                                     600  14    19    approx. 0.546       
10   0.25 60.4  0.312                                                     
                    0.305                                                 
                         7.2  143,000                                     
                                    1630  16    26    approx. 0.547       
11   0.50 60.8  0.124                                                     
                    0.121                                                 
                         8.0  125,000                                     
                                    1850  16    27    approx. 0.551       
12   1.0  61.0  0.111                                                     
                    0.096                                                 
                         6.8  132,000                                     
                                    1890  17    26    approx. 0.553       
13   2.0  60.2  0.108                                                     
                    0.076                                                 
                        11.1   81,000                                     
                                    1490  20    35    approx. 0.546       
14   4.0  56.7  0.105                                                     
                    0.080                                                 
                        15.1   61,000                                     
                                    1530  22    35    approx.             
__________________________________________________________________________
                                                      0.513               
In examples 9-14, the amount of silane coating is varied between 0% and 4.0% to show how changes in the level of silane effect key properties of the electrical substrate material of the present invention. As is clear from TABLE 2, even very low levels of silane (0.25%) will have reduced water-absorption and improved peel strength. Silane levels above 1% seem to favor coupling to the copper foil which result in further improvements to peel strength. However, above roughly 1% silane coating levels, the coupling between the fluoropolymer and the filler is reduced as is evidenced by decreases in strength and increases in thermal expansion coefficients. The preferred amount of silane is at least 1% and more preferably in the range of between 1 and 2% of the total weight of ceramic filler.
In Examples 15-19, four different types of thermally stable silane coatings are compared to a control having no silane coating. All coatings are done at 1% levels. As shown in TABLE 3, all coatings provide dramatic, suprising and unexpected results in terms of reducing water absorption, improving copper adhesion and improving strength. As mentioned, DC X1-6100 is the preferred coating due to thermal stability and consistency of the below listed favorable results.
                                  TABLE 3                                 
__________________________________________________________________________
                                                      Filler Volume       
                                                      Fraction (%)        
                                                      (Assuming X1 =      
EX-          DEN-                                                         
                 24 hr.                                                   
                     48 hr.                                               
                         PEEL  YOUNG'S                                    
                                     TENSILE                              
                                           DI-   DISSI-                   
                                                      (ASH)/(100) -       
AM-       ASH                                                             
             SITY                                                         
                 50° C.                                            
                     50° C.                                        
                         STRENGTH                                         
                               MODULUS                                    
                                     STRENGTH                             
                                           ELECTRIC                       
                                                 PATION                   
                                                      .01 where           
PLES                                                                      
   COATING                                                                
          (%)                                                             
             (g/cm.sup.3)                                                 
                 (%) (%) (lb/inch)                                        
                               (kpsi)                                     
                                     (psi) CONSTANT                       
                                                 FACTOR                   
                                                      ASH = 1.0           
                                                      g/cm.sup.3)         
__________________________________________________________________________
15 Prosil 246 @                                                           
          51.9                                                            
             2.160                                                        
                 0.218                                                    
                     0.246                                                
                          9.3   97   1200  2.84  0.0015                   
                                                      approx. 0.507       
   1%                                                                     
16 A-50 @ 1%                                                              
          50.8                                                            
             2.168                                                        
                 0.681                                                    
                     0.690                                                
                          8.8  102   1200  2.83  0.0017                   
                                                      approx. 0.498       
17 DC X1- 51.8                                                            
             2.162                                                        
                 0.217                                                    
                     0.248                                                
                         10.5   99   1300  2.84  0.0015                   
                                                      approx. 0.506       
   6100 @ 1%                                                              
18 DC Z-6020 @                                                            
          52.6                                                            
             2.150                                                        
                 0.569                                                    
                     0.575                                                
                          9.9  120   1150  2.83  0.0016                   
                                                      approx. 0.511       
   1%                                                                     
19 No Coating                                                             
          51.6                                                            
             2.160   0.895                                                
                          7.8   91    900  2.83  0.0016                   
                                                      approx.             
__________________________________________________________________________
                                                      0.504               
The electrical substrate material of the present invention is highly filled with ceramic, preferably silica. FIG. 7 is a graphical representation showing the effect of filler level on the X-Y plane thermal expansion coefficient of the material of the present invention. The measurements were taken on a plurality of samples (having varying amounts of filler) as measured on a thermo-mechanical analyzer over a temperature range of 0°-120° C. It will be appreciated that although it is difficult to match the thermal expansion of ceramics, it has been demonstrated (see FIG. 10 discussed below) that CTE's in the 10-20 ppm °C.-1 range can result in high solder joint reliability, as stresses are kept at a minimum due to the high degree of compliancy of the material of the present invention. Thus, as shown in FIG. 7, at relatively high percentages of ceramic filler, the CTE lessens and approaches that of ceramics.
FIG. 8 shows the effect of varying the amount of filler level on the Z-direction thermal expansion coefficient also as measured by a thermo-mechanical analyzer over a temperature range of 0°-120° C. Again, at high filler levels, the Z-direction CTE goes steadily downwardly (see also FIG. 11 discussed below). Significantly, as is evident in both. FIGS. 7 and 8, the X-Y and Z direction CTE's may be tailored to favor copper, ceramic or other materials simply by adjusting filler levels.
Table 4 shows the effect of fiber level and filler size distribution on processing thin (i.e., 0.0015") sheet materials (all of the samples having a ceramic filler content of about 62%). Samples were made (1) with standard filler size distribution (mean particle diameter of roughly 10-15 μm); (2) with equal to or greater than 30 μm particles removed: (3) with 1% glass fiber; and (4) with no glass fiber. The results clearly show that manufacture of very thin sheet materials is much easier for compositions without glass fibers and without filler particles having a larger mean particle dimension.
              TABLE 4                                                     
______________________________________                                    
Effect of Fiber Level & Filler Size Distribution                          
on processing of 0.0015" sheet materals                                   
Standard Filler     Standard Filler w/                                    
size distribution   all particles 30 μm removed                        
______________________________________                                    
1% glass                                                                  
        Many pinholes   Few pinholes                                      
fiber   poor edge quality                                                 
                        poor edge quality                                 
        (tears)         (tears)                                           
        unable to reach 0.0015"                                           
        in 5 calender passes                                              
0% glass                                                                  
        Many pinholes   No pinholes                                       
fiber   good edge quality                                                 
                        good edge quality                                 
______________________________________                                    
COMPARISON OF THE PRESENT INVENTION WITH PRIOR ART ELECTRICAL SUBSTRATE MATERIALS
The detailed evaluations of the electrical substrate material of the present invention relative to known prior art substrate materials are set forth below and are divided into two parts: electrical performance: and surface mount reliability. Wherever possible, the performance of the present invention (RO-2800) is compared to other prior art PWB substrate materials and integrated circuit chip carriers such as PTFE/microfiberglass, epoxy/woven glass, polyimide/woven glass, PTFE/woven glass, polyimide/woven quartz, and polyimide/Kevlar (a registered trademark of E.I. duPont de Nemours Co.).
I. ELECTRICAL PERFORMANCE
A. Propagation Delay
The silane coated ceramic filled fluoropolymer PWB substrate material in accordance with the present invention (RO-2800) is the lowest dielectric constant PWB material with respectable performance for surface mount applications, as will be demonstrated hereinafter. With a dielectric constant of 2.3-2.9, propagation delays can be reduced by as much as 30% compared with the woven glass fabric reinforced epoxy and polyimide materials, and by as much as 10% over polyimide laminates reinforced with quartz or Kevlar fabric. This data is summarized in TABLE 5. It will be appreciated that while PTFE/microfiberglass materials do exhibit lower dielectric constants and propagation delays relative to the present invention, the adverse thermo-mechanical properties of these materials make them unsuitable for surface mount applications.
              TABLE 5                                                     
______________________________________                                    
Effect of Dielectric Constant on Propagation Delay                        
                       Propagation                                        
Dielectric Dielectric  Delay     Speed                                    
Material   Constant    (nsec/foot)                                        
                                 Efficiency*                              
______________________________________                                    
Air        1.0         1.0167    100%                                     
PTFE/      2.2         1.5080    67%                                      
Microfiberglass                                                           
RO-2800 (Present                                                          
           2.8         1.7012    60%                                      
Invention)                                                                
Polyimide/Woven                                                           
           3.35        1.8609    55%                                      
Quartz                                                                    
Polyimide/Woven                                                           
           3.6         1.9291    53%                                      
Kevlar                                                                    
Polyimide/Woven                                                           
           4.5         2.1567    47%                                      
Glass                                                                     
Epoxy/Woven Glass                                                         
           4.8         2.2275    46%                                      
______________________________________                                    
 ##STR1##                                                                 
B. Crosstalk
Crosstalk can be defined as undesirable coupling of energy between signal traces. In high peformance digital computer systems, circuit densities are very high, resulting in small spacing between traces. As the line spacing decreases, crosstalk becomes a major problem.
In this comparison, the "dual" stripline geometry shown in FIG. 5 was used because of its widespread use in multi-layer constructions. The line widths were held constant at 0.005", and the total ground plane spacing was chosen to maintain a nominal characteristic impedance of 50 ohms when the X and Y direction signal layers were separated by 0.005" dielectric.
As is shown is FIG. 9, a 6 mil space between signal traces would result in less than 2% crosstalk for the present invention (RO-2800), compared to an 8 mil space required for polyimide/quartz and 11.5 mil space required for epoxy/glass. These differences are very significant in high performance applications, enabling circuit designers to route traces closer to one another when using the novel PWB substrate in accordance with the present invention.
C. Rise-Time Degradation
Rise-time degradation through the PWB becomes a significant problem when trace lengths are long and switching speeds are increased. The rise-time degradation for an RO-2800 (present invention) circuit was compared to some conventional PWB materials (epoxy/woven glass and polyimide/woven glass) and a high performance "microwave" material (PTFE/microfiberglass). Standard stripline constructions (see FIG. 4) were chosen, with line widths in the 3.9 to 5.9 mil range and Zo in the 49 to 70 ohms range.
A Tektronix 7854 oscilloscope with the 7S12 TDR plug-in module was used for all tests. Trace lengths were 19.6 inches long, the TDR rise-time was typically 25 psec and input rise-time was typically 137 psec.
The rise-time degradation data is shown in TABLE 6. From this data, two effects are noted:
(1) the effect of the dielectric material; and
(2) the effect of circuit construction.
The first effect can be attributed to the difference in dissipation factors for the various materials tested, particularly at high frequencies. Attenuation of the high frequency components of a signal pulse results in a less sharply defined pulse and therefore, rise-time degradation. PTFE/microfiberglass and RO-2800 laminates exhibit low dissipation factors well into the GHz range, with values at 10 GHz as low as 0.0008 and 0.002 respectively. Data describing the dissipation factor at high frequencies could not be found for the other materials tested. However, even at 1 MHz, the dissipation factors are in the 0.01 to 0.02 range. The tests show that RO-2800 (present invention) resulted in a 40 to 55% reduction in rise-time degradation compared with the polyimide/glass and epoxy/glass materials. As expected, the lowest loss material, PTFE/microfiberglass, resulted in the lowest rise-time degradation, exhibiting an 18% improvement over the present invention (RO-2800).
              TABLE 6                                                     
______________________________________                                    
Rise-Time Degradation                                                     
                                Tr    Tr/L                                
Material      W(mils)  Zo(ohms) (psec)                                    
                                      (psec/ft)                           
______________________________________                                    
PTFE/Microfiberglass                                                      
              4.8      64       139   86                                  
PTFE/Microfiberglass                                                      
              5.1      79       111   68                                  
RO-2800       5.0      49       165   102                                 
RO-2800       4.4      51       165   102                                 
RO-2800       5.1      69       139   86                                  
RO-2800       5.2      75       139   86                                  
Epoxy/Woven Glass                                                         
              4.9      51       366   225                                 
Epoxy/Woven Glass                                                         
              4.7      75       303   187                                 
Polyimide/Woven Glass                                                     
              5.9      58       236   145                                 
Polyimide/Woven Glass                                                     
              3.9      74       259   159                                 
______________________________________                                    
 Stripline circuits, trace length (L) = 19.6 inches                       
 Tr = (Tr.sub.0 .sup.2 -Tr.sub.1 .sup.2).sup.3  = risetime degradation    
 Tr/L = rise = time degradation per unit trace length                     
D. Transmission Line Losses
A number of transmission line parameters affect the attenuation of microwave signals in stripline, including: Zo. .di-elect cons.r, loss tangent or dissipation factor, conductor resistivity, surface finishes, conductor thicknesses, and circuit configurations.
Results for calculations on RO-2800 (present invention) and PTFE/microfiberglass materials for 50 ohm stripline with 5 mil line width using 1 ounce copper are shown in TABLE 7. PTFE/microfiberglass is used for microwave applications requiring low loss. As can be seen in the table, RO-2800 performed as well as the premiere microwave materials from 1 MHz to 10 GHz in this stripline construction. This particular construction was chosen because of the trend towards narrow lines for high speed digital packaging.
              TABLE 7                                                     
______________________________________                                    
Transmission Loss Versus Frequency,                                       
RO-2800 Versus "Microwave Material"                                       
            Transmission Loss (db/inch)                                   
Frequency (GHz)                                                           
              RO-2800  PTFE/Microfiberglass                               
______________________________________                                    
0.001         9.6 × 10.sup.-5                                       
                       9.5 × 10.sup.-5                              
0.001         9.6 × 10.sup.-4                                       
                       9.5 × 10.sup.-4                              
0.1           9.6 × 10.sup.-3                                       
                       9.5 × 10.sup.-3                              
0.25          0.022    0.024                                              
0.5           0.048    0.048                                              
1.0           0.096    0.095                                              
5.0           0.479    0.477                                              
10.0          0.957    0.953                                              
______________________________________                                    
 50 ohm stripline                                                         
 5 mil line width. 1 ounce ED copper                                      
II. SURFACE MOUNT RELIABILITY
Some key thermal/mechanical properties of several materials are listed in Table 8. The two materials listed at the bottom of the table are reference materials: alumina is often used as a chip carrier material, and copper is usually the metal conductor on a PWB. All of the other materials are PWB materials that can be separated into the following categories: fluoropolymer materials (PTFE/glass, RO-2800), specialty reinforcements (polyimide/quartz, polyimide/KEVLAR) and conventional materials (polyimide/glass, epoxy/glass).
                                  TABLE 8                                 
__________________________________________________________________________
THERMAL/MECHANICAL PROPERTIES                                             
                    Thermal                                               
                          Modulus of                                      
          CTE-xy                                                          
               CTE-z                                                      
                    Conductivity                                          
                          Elasticity                                      
                                Density                                   
Material  (ppm ° C.)                                               
               (ppm ° C.)                                          
                    W/m/K (Mpsi)                                          
                                (lb/in.sup.3)                             
__________________________________________________________________________
PTFE/glass                                                                
          24   261  0.26  0.14  0.079                                     
RO2800    16-19                                                           
               24   0.44  0.1   0.072                                     
Polyimide/quartz                                                          
          6-8  34   0.13  4.0   0.07                                      
Polyimide/KEVLAR                                                          
          3.4-6.7                                                         
               83   0.12  4.0   0.06                                      
Polyimide/glass                                                           
          11.7-14.2                                                       
               60   0.35  2.8   0.066                                     
Epoxy/glass                                                               
          12.8-16                                                         
               189  0.18  2.5   0.065                                     
Alumina   6.5  6.5  16.8  37.0  0.13                                      
Copper    16.9 16.9 394   17.0  0.324                                     
__________________________________________________________________________
The present invention was evaluated for use in surface mount applications by thermal cycling test boards populated with leadless ceramic chip carriers.
The compiled results of solder joint failure versus thermal cycle number for each material in Table 8 are graphically shown in FIG. 10. As shown, the performance of the present invention RO-2800A) is superior to that of standard epoxy/glass substrates and glass-reinforced fluoropolymer materials, and only slightly less reliable than polyimide/Kevlar and polyimide-quartz boards. If additional filler is added to RO-2800 to reduce the X-Y CTE to approximately 10 ppm °C., then surface mount reliability can be even better than the polyimide quartz boards. A material with this additional filler is identified as RO-2800B in FIG. 10.
As the thermal expansion coefficient of the PWB approaches that of the ceramic chip carrier, the differential strain is reduced, resulting in reduced stress at the solder joints of surface mounted LCCC's. Although the CTE of the present invention is not as closely matched to ceramic chip carriers as some other substrate alternatives, its compliant nature plays a major role in reducing stress at the solder joint. This results in surface mount reliability that is comparable to these other materials for 28 and 68 I/O LCCC's.
FIG. 11 is a graphical representation of the effect of substrate CTE on plated through hole (PTH) reliability. In FIG. 11, a plot of differential strain versus CTE of the PWB in the Z-direction is shown. For a ΔT of 263° C., differential strains for most PWB materaisl will lie between 2 and 13%; for RO-2800, this value is less than 1%.
Primarily due to its lower dielectric constant and lower dissipation factor (especially at high frequencies), the PWB substrate material of the present invention exhibits improved electrical performance over other materials being considered for high speed digital applications. A PWB material that offers designers improved electrical performance, and a substrate suitable for SMT with reliable plated through holes will go a long way toward optimizing the interconnection system, complementing the performance of high speed logic devices.
Other features and advantages of the present invention are summarized in the following TABLE 9.
              TABLE 9                                                     
______________________________________                                    
FEATURE          BENEFITS OVER PRIOR ART                                  
______________________________________                                    
Low dielectric constant                                                   
                 High propagation velocity (as                            
                 much as 25% higher)                                      
                 Low cross-talk (as much as an                            
                 order of magnitude lower)                                
                 Reduced Multilayer board                                 
                 thicknesses                                              
Low loss at high frequencies                                              
                 Lower rise-time degradation                              
                 (by as much as 4 times)                                  
                 Suitable for microwave use                               
Low CTE X-Y plane.                                                        
                 Suitable for surface mount                               
compliant        technology                                               
Low CTE Z-direction                                                       
                 Excellent plated through hole                            
                 reliability                                              
Excellent, and thickness                                                  
                 Improved Zo control                                      
control                                                                   
Higher thermal conductivity                                               
                 Better power dissipation                                 
______________________________________                                    
Finally, it is clear from the foregoing data and comparisons that while some PWB substrates have better electrical properties than RO-2800 (e.g. PTFE/Glass) and some PWB substrates have better thermal expansion properties than RO-2800 (e.g. polyimide/quartz, and polyimide/Kevlar), none of these prior art electrical substrate materials have as good combined electrical and thermo-mechanical properties which make them well suited for the next generation of high speed electronic components as well as surface mount technology.
While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.

Claims (46)

What is claimed is:
1. An electrical substrate material comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 55 weight percent of the total substrate material.Iadd., said ceramic filler comprising silica, said silica comprising amorphous fused silica powder.Iaddend.;
said ceramic filler being coated with a silane coating;
at least one layer of metal being disposed on at least a portion of said electrical substrate material.
2. The material of claim 1 including:
fiber reinforcement material.
3. The material of claim 2 wherein:
said fiber reinforcement material has a weight percent of equal to or less than 2%.
4. The material of claim 2 wherein:
said fiber reinforcement material is glass fiber.
5. The material of claim 4 wherein:
said glass fiber Is microglass fiber.
6. The material of claim 1 wherein said fluoropolymeric material is selected from the group .[.comprising.]. .Iadd.consisting .Iaddend.of:
polytetrafluoroethylene, hexa fluoropropene, tetrafluoroethylene .[.or.]. .Iadd.and .Iaddend.perfluoro alkyl vinyl ether. .[.7. The material of claim 1 wherein said ceramic filler comprises silica..]..[.8. The material of claim 7 wherein said silica comprises amorphous fused silica
powder..]. . The material of claim 1 wherein said silane coating is selected from the group .[.comprising.]. .Iadd.consisting of.Iaddend.:
p-chloromethyl phenyl trimethoxy silane, amino ethyl amino trimethoxy silane, .Iadd.and .Iaddend.a mixture of phenyl trimethoxy silane and amino
ethyl amino propyl trimethoxy silane. 10. The material of claim 1 wherein:
said silane coating is in an amount of at least 1 weight percent relative
to the weight of the ceramic filler. 11. The material of claim 1 wherein said ceramic filler comprises particles and wherein the mean particle size
varies from about 10 to 15 μm. 12. In a multilayer circuit including at least a first circuit layer and a second circuit layer, the improvement comprising:
an adhesive layer sandwiched between the first and second circuit layers, said adhesive layer comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 55 weight percent of the total adhesive layer.Iadd., said ceramic filler comprising silica, said silica comprising amorphous fused silica powder.Iaddend.; and
said ceramic filler being coated with a silane coating. 13. The multilayer circuit of claim 12 including:
at least one plated through hole. 14. The multilayer circuit of claim 12 including:
fiber reinforcement material. 15. The multilayer circuit of claim 14 wherein:
said fiber reinforcement material has a weight percent of equal to or less
than 2%. 16. The multilayer circuit of claim 14 wherein:
said fiber reinforcement material is glass fiber. 17. The multilayer circuit of claim 16 wherein:
said glass fiber is microglass fiber. 18. The multilayer circuit of claim 12 wherein said fluoropolymeric material is selected from the group .[.comprising.]. .Iadd.consisting of.Iaddend.:
polytetrafluoroethylene, hexa fluoropropene, tetrafluoroethylene .[.or.]. .Iadd.and .Iaddend.perfluoro alkyl vinyl ether. .[.19. The multilayer circuit of claim 12 wherein said ceramic filler comprises silica..]..[.20. The multilayer circuit of claim 19 wherein said silica comprises amorphous
fused silica powder..].21. The multilayer circuit of claim 12 wherein said silane coating is selected from the group .[.comprising.]. .Iadd.consisting of.Iaddend.:
p-chloromethyl phenyl trimethoxy silane, amino ethyl amino trimethoxy silane, .Iadd.and .Iaddend.a mixture of phenyl trimethoxy silane and amino
ethyl amino propyl trimethoxy silane. 22. The multilayer circuit of claim 12 wherein:
said silane coating is in an amount of at least 1 weight percent relative
to the weight of the ceramic filler. 23. The multilayer circuit of claim 12 wherein said ceramic filler comprises particles and wherein the mean
particle size varies from about 10 to 15 μm. 24. An electrical substrate material comprising: night mom
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 50 volume percent of the total substrate material.Iadd., said ceramic filler comprising silica, said silica comprising amorphous fused silica powder.Iaddend.;
said ceramic filler being coated by a silane coating; and
at least one layer of metal being disposed on at least a portion of said
electrical substrate material. 25. The material of claim 24 including:
fiber reinforcement material. 26. The material of claim 25 wherein:
said fiber reinforcement material is glass fiber. 27. The material of claim 26 wherein:
said glass fiber is microglass fiber. 28. The material of claim 24 wherein said fluoropolymeric material is selected from the group .[.comprising.]. .Iadd.consisting of.Iaddend.:
polytetrafluoroethylene, hexa fluoropropene, tetrafluoroethylene .[.or.]. .Iadd.and .Iaddend.perfluoro allyl vinyl ether. .[.29. The material of claim 28 wherein said ceramic filler comprises silica..]..[.30. The material of claim 29 wherein said silica comprises amorphous fused silica
powder..].31. The material of claim 24 wherein said silane coating is selected from the group .[.comprising.]. .Iadd.consisting of.Iaddend.:
p-chloromethyl phenyl trimethoxy silane, amino ethyl amino trimethoxy silane, .Iadd.and .Iaddend.a mixture of phenyl trimethoxy silane and amino
ethyl amino propyl trimethoxy silane. 32. The material of claim 24 wherein said ceramic filler comprises particles and wherein the mean particle size
varies from about 10 to 15 μm. 33. In a multilayer circuit including at least a first circuit layer and a second circuit layer, the improvement comprising:
an adhesive layer sandwiched between the first and second circuit layers, said adhesive layer comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 50 volume percent of the total adhesive layer.Iadd., said ceramic filler comprising silica said silica comprising amorphous fused silica powder.Iaddend.; and
said ceramic filler being coated with a silane coating. 34. The multilayer circuit of claim 33 including:
at least one plated through hole. 35. The multiplayer circuit of claim 33 including:
fiber reinforcement material. 36. The multilayer circuit of claim 35 wherein:
said fiber reinforcement material is glass fiber. 37. The multilayer circuit of claim 36 wherein:
said glass fiber is microglass fiber. 38. The multilayer circuit of claim 33 wherein said fluoropolymeric material is selected from the group .[.comprising.]. .Iadd.consisting of.Iaddend.:
polytetrafluoroethylene, hexa fluoropropene, tetrafluoroethylene .[.or.]. .Iadd.and .Iaddend.perfluoro allyl vinyl ether. .[.39. The multilayer circuit of claim 33 wherein said ceramic filler comprises silica..]..[.40. The multilayer circuit of claim 39 wherein said silica comprises amorphous
fused silica powder..].41. The multilayer circuit of claim 33 wherein said silane coating is selected from the group .[.comprising.]. .Iadd.consisting of.Iaddend.:
p-chloromethyl phenyl trimethoxy silane, amino ethyl amino trimethoxy silane, .Iadd.and .Iaddend.a mixture of phenyl trimethoxy silane and amino
ethyl amino propyl trimethoxy silane. 42. The multilayer circuit of claim 33 wherein said ceramic filler comprises particles and wherein the mean particle size varies from about 10 to 15 μm. .Iadd.43. An electrical substrate material comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 55 weight percent of the total substrate material, said ceramic comprising silica, said silica comprising amorphous fused silica powder;
said ceramic filler being coated with a silane coating;
at least one layer of metal being disposed on at least a portion of said electrical substrate material; and
said electrical substrate material having a dielectric constant of between
about 2.7 to 2.9. .Iaddend..Iadd.44. The material of claim 43 including:
said substrate material having a dissipation factor in the range of about 0.0008 to 0.002 at 10 GHz. .Iaddend..Iadd.45. The material of claim 44 wherein:
said dissipation factor is equal to or less than about 0.0017 at 10 GHz. .Iaddend..Iadd.46. The material of claim 43 wherein said substrate material has an X, Y and Z axis and including:
a coefficient of thermal expansion (CTE) in the X-Y plane in the range of about 10 to about 22 ppm/°C. .Iaddend..Iadd.47. The material of claim 46 wherein:
said CTE in the X-Y plane is in the range of about 16 to about 19
ppm/°C. .Iaddend..Iadd.48. The material of claim 43 wherein said substrate material has an X, Y and Z axis and including:
a coefficient of thermal expansion (CTE) in the Z axis in the range of about 15 to about 35 ppm/°C. .Iaddend..Iadd.49. The material of claim 48 wherein:
said CTE in the Z axis is about 24 ppm/°C. .Iaddend..Iadd.50. An electrical substrate material comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 55 weight percent of the total substrate material, said ceramic filler comprising silica, said silica comprising amorphous fused silica powder;
said ceramic filler being coated with a silane coating;
at least one layer of metal being disposed on at least a portion of said electrical substrate material; and
said electrical substrate material having a dissipation factor in the range of equal to or less than about 0.0017 at 10 GHz. .Iaddend..Iadd.51. The material of claim 50 wherein said substrate material has an X, Y and Z axis and including:
a coefficient of thermal expansion (CTE) in the X-Y plane in the range of about 10 to about 22 ppm/°C. .Iaddend..Iadd.52. The material of claim 51 wherein:
said CTE in the X-Y plane is in the range of about 16 to about 19
ppm/°C. .Iaddend..Iadd.53. The material of claim 50 wherein said substrate material has an X, Y and Z axis and including:
a coefficient of thermal expansion (CTE) in the Z axis in the range of about 15 to about 35 ppm/°C. .Iaddend..Iadd.54. The material of claim 53 wherein:
said CTE in the Z axis is about 24 ppm/°C. .Iaddend..Iadd.55. An electrical substrate material comprising:
fluoropolymeric material;
seismic filler material, said filler material being in an amount of at least about 55 weight percent of the total substrate material, said ceramic filler comprising silica, said silica comprising amorphous fused silica powder;
said ceramic filler being coated with a silane coating;
at least one layer of metal being disposed on at least a portion of said electrical substrate material; and
said electrical substrate material having a X, Y and Z axis and having a coefficient of thermal expansion in the Z-axis of about 15 to about 35 ppm/°C. .Iaddend..Iadd.56. The material of claim 55 including:
said substrate material having a dissipation factor in the range of about 0.0008 to 0.002 at 10 GHz. .Iaddend..Iadd.57. The material of claim 55 wherein:
said CTE in the Z axis is about 24 ppm/°C. .Iaddend..Iadd.58. An electrical substrate material comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 55 weight percent of the total substrate material, said ceramic filler comprising silica, said silica comprising amorphous fused silica powder;
said ceramic filler being coated with a silane coating;
at least one layer of copper disposed on at least a portion of said electrical substrate material; and
said electrical substrate material having a X, Y and Z axis and having a coefficient of thermal expansion (CTE) in the X-Y plane in the range of about 10 to about 22 ppm/°C. .Iaddend..Iadd.59. The material of claim 58 including:
said substrate material having a dissipation factor in the range of about 0.0008 to 0.002 at 10 GHz. .Iaddend..Iadd.60. The material of claim 58 wherein:
said CTE in the X-Y plane is in the range of about 16 to about 19
ppm/°C. .Iaddend..Iadd.61. An electrical material comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 55 weight percent of the total substrate material, said ceramic filler comprising silica, said silica comprising amorphous fused silica powder;
said ceramic filler being coated with a silane coating;
at least one layer of metal being disposed on at least a portion of said electrical substrate material; and
said electrical substrate material having a X, Y and Z axis and including a coefficient of thermal expansion (CTE) in the X-Y plane in the range of about 10 to 22 ppm/°C. and a CTE in the Z axis in the range of about 15 to about 35 ppm/°C. .Iaddend..Iadd.62. The material of claim 61 including:
said substrate material having a dissipation factor in the range of about 0.0008 to 0.002 at 10 GHz. .Iaddend..Iadd.63. The material of claim 62 wherein:
said dissipation factor is equal to or less than about 0.0017 at 10 GHz. .Iaddend..Iadd.64. The material of claim 61 wherein:
said CTE in the X-Y plane is in the range of about 16 to about 19 ppm/°C. .Iaddend..Iadd.65. The material of claim 64 wherein:
said CTE in the Z axis is about 24 ppm/°C. .Iaddend..Iadd.66. The material of claim 61 wherein:
said CTE in the Z axis is about 24 ppm/°C. .Iaddend..Iadd.67. The material of claim 61 including:
a dielectric constant in the range of about 2.7 to about 2.9. .Iaddend..Iadd.68. The material of claim 67 including:
said substrate material having a dissipation factor in the range of about 0.0008 to 0.002 at 10 GHz. .Iaddend..Iadd.69. The material of claim 68 wherein:
said dissipation factor is equal to or less than about 0.0017 at 10 GHz. .Iaddend..Iadd.70. The material of claim 67 wherein:
said CTE in the X-Y plane is in the range of about 16 to about 19 ppm/°C. .Iaddend..Iadd.71. The material of claim 70 wherein:
said CTE in the Z axis is in the range of about 24 ppm/°C. .Iaddend..Iadd.72. The material of claim 67 wherein:
said CTE in the Z axis is in the range of about 24 ppm/°C.
.Iaddend..Iadd.73. An electrical substrate material comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 50 volume percent of the total substrate material, said ceramic filler comprising silica, said silica comprising amorphous fused silica powder;
said ceramic filler being coated with a silane coating;
at least one layer of metal being disposed on at least a portion of said electrical substrate material; and
said electrical substrate material having a dielectric constant of between about 2.7 to 2.9. .Iaddend..Iadd.74. The material of claim 73 including:
said substrate material having a dissipation factor in the range of about 0.0008 to 0.002 at 10 GHz. .Iaddend..Iadd.75. The material of claim 74 wherein:
said dissipation factor is equal to or less than about 0.0017 at 10 GHz. .Iaddend..Iadd.76. The material of claim 73 wherein said substrate material has an X, Y and Z axis and including:
a coefficient of thermal expansion (CTE) in the X-Y plane in the range of about 10 to about 22 ppm/°C. .Iaddend..Iadd.77. The material of claim 76 wherein:
said CTE in the X-Y plane is in the range of about 16 to about 19
ppm/°C. .Iaddend..Iadd.78. The material of claim 73 wherein said substrate material has an X, Y and Z axis and including:
a coefficient of thermal expansion (CTE) in the Z axis in the range of about 15 to about 35 ppm/°C. .Iaddend..Iadd.79. The material of claim 78 wherein:
said CTE in the Z axis is about 24 ppm/°C. .Iaddend..Iadd.80. An electrical substrate material comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 50 volume percent of the total substrate material, said ceramic filler comprising silica, said silica comprising amorphous fused silica powder;
said ceramic filler being coated with a silane coating;
at least one layer of metal being disposed on at least a portion of said electrical substrate material; and
said electrical substrate material having a dissipation factor in the range of equal to or less than about 0.0017 at 10 GHz. .Iaddend..Iadd.81. The material of claim 80 wherein said substrate material has an X, Y and Z axis and including:
a coefficient of thermal expansion (CTE) in the X-Y plane in the range of about 10 to about 22 ppm/°C. .Iaddend..Iadd.82. The material of claim 81 wherein:
said CTE in the X-Y plane is in the range of about 16 to about 19
ppm/°C. .Iaddend..Iadd.83. The material of claim 80 wherein said substrate material has an X, Y and Z axis and including:
a coefficient of thermal expansion (CTE) in the Z axis in the range of about 15 to about 35 ppm/°C. .Iaddend..Iadd.84. The material of claim 83 wherein:
said CTE in the Z axis is about 24 ppm/°C. .Iaddend..Iadd.85. An electrical substrate material comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 50 volume percent of the total substrate material, said ceramic filler comprising silica, said silica comprising amorphous fused silica powder;
said ceramic filler being coated with a silane coating;
at least one layer of metal being disposed on at least a portion of said electrical substrate material; and
said electrical substrate material having a X, Y and Z axis and having a coefficient of thermal expansion in the Z-axis of about 15 to about 35 ppm/°C. .Iaddend..Iadd.86. The material of claim 85 including:
said substrate material having a dissipation factor in the range of about 0.0008 to 0.002 at 10 GHz. .Iaddend..Iadd.87. The material of claim 85 wherein:
said CTE in the Z axis is about 24 ppm/°C. .Iaddend..Iadd.88. An electrical substrate material comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 50 volume percent of the total substrate material, said ceramic filler comprising silica, said silica comprising amorphous fused silica powder;
said ceramic filler being coated with a silane coating;
at least one layer of copper disposed on at least a portion of said electrical substrate material; and
said electrical substrate material having a X, Y and Z axis and having a coefficient of thermal expansion (CTE) in the X-Y plane in the range of about 10 to about 22 ppm/°C. .Iaddend..Iadd.89. The material of claim 88 including:
said substrate material having a dissipation factor in the range of about 0.0008 to 0.002 at 10 GHz. .Iaddend..Iadd.90. The material of claim 88 wherein:
said CTE in the X-Y plane is in the range of about 16 to about 19
ppm/°C. .Iaddend..Iadd.91. An electrical substrate material comprising:
fluoropolymeric material;
ceramic filler material, said filler material being in an amount of at least about 50 volume percent of the total substrate material, said ceramic filler comprising silica, said silica comprising amorphous fused silica powder;
said ceramic filler being coated with a silane coating;
at least one layer of metal being disposed on at least a portion of said electrical substrate material; and
said electrical substrate material having a X, Y and Z axis and including a coefficient of thermal expansion (CTE) in the X-Y plane in the range of about 10 to 22 ppm/°C. and a CTE in the Z axis in the range of about 15 to about 35 ppm/°C. .Iaddend..Iadd.92. The material of claim 91 including:
said substrate material having a dissipation factor in the ranges of about 0.0008 to 0.002 at 10 GHz. .Iaddend..Iadd.93. The material of claim 92 wherein:
said dissipation factor is equal to or less than about 0.0017 at 10 GHz. .Iaddend..Iadd.94. The material of claim 91 wherein:
said CTE in the X-Y plane is in the range of about 16 to about 19 ppm/°C. .Iaddend..Iadd.95. The material of claim 94 wherein:
said CTE in the Z axis is about 24 ppm/°C. .Iaddend..Iadd.96. The material of claim 91 wherein:
said CTE in the Z axis is about 24 ppm/°C. .Iaddend..Iadd.97. The material of claim 91 including:
a dielectric constant in the range of about 2.7 to about 2.9. .Iaddend..Iadd.98. The material of claim 97 including:
said substrate material having a dissipation factor in the range of about 0.0008 to 0.002 at 10 GHz. .Iaddend..Iadd.99. The material of claim 98 wherein:
said dissipation factor is equal to or less than about 0.0017 at 10 GHz. .Iaddend..Iadd.100. The material of claim 97 wherein:
said CTE in the X-Y plane is in the range of about 16 to about 19 ppm/°C. .Iaddend..Iadd.101. The material of claim 100 wherein:
said CTE in the Z axis is in the range of about 24 ppm/°C. .Iaddend..Iadd.102. The material of claim 97 wherein:
said CTE in the Z axis is in the range of about 24 ppm/°C. .Iaddend.
US08/379,991 1987-02-17 1995-01-27 Electrical substrate material comprising amorphous fused silica powder Expired - Lifetime USRE36396E (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US08/379,991 USRE36396E (en) 1987-02-17 1995-01-27 Electrical substrate material comprising amorphous fused silica powder

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US07/015,191 US4849284A (en) 1987-02-17 1987-02-17 Electrical substrate material
US08/379,991 USRE36396E (en) 1987-02-17 1995-01-27 Electrical substrate material comprising amorphous fused silica powder

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US07/015,191 Reissue US4849284A (en) 1987-02-17 1987-02-17 Electrical substrate material

Publications (1)

Publication Number Publication Date
USRE36396E true USRE36396E (en) 1999-11-16

Family

ID=26687063

Family Applications (1)

Application Number Title Priority Date Filing Date
US08/379,991 Expired - Lifetime USRE36396E (en) 1987-02-17 1995-01-27 Electrical substrate material comprising amorphous fused silica powder

Country Status (1)

Country Link
US (1) USRE36396E (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6319811B1 (en) * 2000-02-22 2001-11-20 Scott Zimmerman Bond ply structure and associated process for interconnection of circuit layer pairs with conductive inks
US6472601B2 (en) * 2001-01-30 2002-10-29 Lockheed Martin Corporation Electrically-conductive, thermally-insulating structure and method
US6572968B2 (en) 1995-06-27 2003-06-03 Hitachi Chemical Co., Ltd. Method of producing prepreg for printed wiring boards, glass fiber material treated with silicone oligomer, and laminate for printed wiring boards
US20060200917A1 (en) * 2005-02-11 2006-09-14 The Board Of Regents Of The University Of Texas System Color compositions and methods of manufacture
US7166361B2 (en) 2000-03-31 2007-01-23 Hitachi Chemical Co., Ltd. Thermosetting resin composition, resin film, metallic foil provided with an insulation material, insulation film provided with a metallic foil on each side, metal-clad laminate, multi-layered metal-clad laminate and multi-layered printed wiring board
US20070033747A1 (en) * 2005-06-17 2007-02-15 The Board Of Regents Of The University Of Texas System Organic/Inorganic Lewis Acid Composite Materials
US20070277702A1 (en) * 2002-06-19 2007-12-06 Russell Chianelli Color compositions
US20090250252A1 (en) * 2008-04-02 2009-10-08 Nitto Denko Corporation Printed circuit board
USRE49929E1 (en) 2017-08-08 2024-04-16 Sumitomo Electric Industries, Ltd. Substrate for high-frequency printed wiring board

Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2539929A (en) * 1948-02-04 1951-01-30 Sparklets Ltd Apparatus for dispensing fluids from a container under pressure
US3025185A (en) * 1957-08-21 1962-03-13 Du Pont Heat stable coated fabric comprising wholly aromatic polyamide fabric coated with copolymer of vinylidene fluoride and hexafluoropropene
US3421972A (en) * 1965-06-28 1969-01-14 Koppers Co Inc Process for directly bonding polytetrafluoroethylene to metal,adhesive composition used therefor and laminated product thereof
US3787281A (en) * 1968-10-29 1974-01-22 Du Pont Forming a hydrolytically stable bond between glass and polytetrafluoroethylene
US4036807A (en) * 1972-05-22 1977-07-19 Imperial Chemical Industries Limited Fluorine-containing organosilicon compounds
US4251432A (en) * 1978-03-06 1981-02-17 Trw Inc. Method of providing curable fluoroelastomer gums having coupling agent coated particulate carbonaceous fillers
US4335180A (en) * 1978-12-26 1982-06-15 Rogers Corporation Microwave circuit boards
US4337155A (en) * 1980-01-22 1982-06-29 Teijin Limited Chemical-resistant wholly aromatic polyamide fiber material
JPS57134806A (en) * 1981-02-12 1982-08-20 Kureha Chemical Ind Co Ltd Dielectric film
US4513055A (en) * 1981-11-30 1985-04-23 Trw Inc. Controlled thermal expansion composite and printed circuit board embodying same
US4634631A (en) * 1985-07-15 1987-01-06 Rogers Corporation Flexible circuit laminate and method of making the same
US4647508A (en) * 1984-07-09 1987-03-03 Rogers Corporation Flexible circuit laminate
US4696851A (en) * 1985-03-25 1987-09-29 Olin Corporation Hybrid and multi-layer circuitry
US4725504A (en) * 1987-02-24 1988-02-16 Polyonics Corporation Metal coated laminate products made from textured polyimide film
US4886699A (en) * 1987-10-26 1989-12-12 Rogers Corporation Glass fiber reinforced fluoropolymeric circuit laminate

Patent Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2539929A (en) * 1948-02-04 1951-01-30 Sparklets Ltd Apparatus for dispensing fluids from a container under pressure
US3025185A (en) * 1957-08-21 1962-03-13 Du Pont Heat stable coated fabric comprising wholly aromatic polyamide fabric coated with copolymer of vinylidene fluoride and hexafluoropropene
US3421972A (en) * 1965-06-28 1969-01-14 Koppers Co Inc Process for directly bonding polytetrafluoroethylene to metal,adhesive composition used therefor and laminated product thereof
US3787281A (en) * 1968-10-29 1974-01-22 Du Pont Forming a hydrolytically stable bond between glass and polytetrafluoroethylene
US4036807A (en) * 1972-05-22 1977-07-19 Imperial Chemical Industries Limited Fluorine-containing organosilicon compounds
US4251432A (en) * 1978-03-06 1981-02-17 Trw Inc. Method of providing curable fluoroelastomer gums having coupling agent coated particulate carbonaceous fillers
US4335180A (en) * 1978-12-26 1982-06-15 Rogers Corporation Microwave circuit boards
US4337155A (en) * 1980-01-22 1982-06-29 Teijin Limited Chemical-resistant wholly aromatic polyamide fiber material
JPS57134806A (en) * 1981-02-12 1982-08-20 Kureha Chemical Ind Co Ltd Dielectric film
US4513055A (en) * 1981-11-30 1985-04-23 Trw Inc. Controlled thermal expansion composite and printed circuit board embodying same
US4647508A (en) * 1984-07-09 1987-03-03 Rogers Corporation Flexible circuit laminate
US4696851A (en) * 1985-03-25 1987-09-29 Olin Corporation Hybrid and multi-layer circuitry
US4634631A (en) * 1985-07-15 1987-01-06 Rogers Corporation Flexible circuit laminate and method of making the same
US4725504A (en) * 1987-02-24 1988-02-16 Polyonics Corporation Metal coated laminate products made from textured polyimide film
US4886699A (en) * 1987-10-26 1989-12-12 Rogers Corporation Glass fiber reinforced fluoropolymeric circuit laminate

Non-Patent Citations (14)

* Cited by examiner, † Cited by third party
Title
"A Guide to Dow Corning Silane Coupling Agents", Dow Corning Corporation, 1985.
"Handbook of Fillers and Reinforcements for Plastics", Van Nostrand Reinhold Company, 1978.
"Metal-Surfaced and other Fluorocarbon Combinations", Electrical Manufacturing, Mar. 1952.
"Silane Adhesion Promoters in Mineral-Filled Composites", Union Carbide Corporation, 1973.
"Silane Coupling Agents in Mineral-Reinforced Elastomers", Union Carbide Corporation, 1974.
"Silane Coupling Agents", Plueddemann 1982, New York.
"The Use of Mixed Silane Coupling Agents", Plueddemann et al, 1985.
A Guide to Dow Corning Silane Coupling Agents , Dow Corning Corporation, 1985. *
Handbook of Fillers and Reinforcements for Plastics , Van Nostrand Reinhold Company, 1978. *
Metal Surfaced and other Fluorocarbon Combinations , Electrical Manufacturing, Mar. 1952. *
Silane Adhesion Promoters in Mineral Filled Composites , Union Carbide Corporation, 1973. *
Silane Coupling Agents , Plueddemann 1982, New York. *
Silane Coupling Agents in Mineral Reinforced Elastomers , Union Carbide Corporation, 1974. *
The Use of Mixed Silane Coupling Agents , Plueddemann et al, 1985. *

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6696155B1 (en) * 1995-06-27 2004-02-24 Hitachi Chemical Company, Ltd. Prepreg for printed wiring boards, resin varnish, resin composition and laminate for printed wiring boards produced by using these substances
US6572968B2 (en) 1995-06-27 2003-06-03 Hitachi Chemical Co., Ltd. Method of producing prepreg for printed wiring boards, glass fiber material treated with silicone oligomer, and laminate for printed wiring boards
US6692792B2 (en) 1995-06-27 2004-02-17 Hitachi Chemical Company, Ltd. Prepreg for printed wiring boards, resin varnish, resin composition, and laminate for printed wiring boards produced by using these substances
US6319811B1 (en) * 2000-02-22 2001-11-20 Scott Zimmerman Bond ply structure and associated process for interconnection of circuit layer pairs with conductive inks
US7166361B2 (en) 2000-03-31 2007-01-23 Hitachi Chemical Co., Ltd. Thermosetting resin composition, resin film, metallic foil provided with an insulation material, insulation film provided with a metallic foil on each side, metal-clad laminate, multi-layered metal-clad laminate and multi-layered printed wiring board
US7736749B2 (en) 2000-03-31 2010-06-15 Hitachi Chemichal Co., Ltd. Thermosetting resin composition, resin film, metallic foil provided with an insulation material, insulation film provided with a metallic foil on each side, metal-clad laminate, multi-layered metal-clad laminate, and multi-layered printed wiring board
US6472601B2 (en) * 2001-01-30 2002-10-29 Lockheed Martin Corporation Electrically-conductive, thermally-insulating structure and method
US20070277702A1 (en) * 2002-06-19 2007-12-06 Russell Chianelli Color compositions
US7429294B2 (en) 2002-06-19 2008-09-30 Board Of Regents, The University Of Texas System Color compositions
US20060200917A1 (en) * 2005-02-11 2006-09-14 The Board Of Regents Of The University Of Texas System Color compositions and methods of manufacture
US7425235B2 (en) 2005-02-11 2008-09-16 The Board Of Regents Of The University Of Texas System Color compositions and methods of manufacture
US20070033747A1 (en) * 2005-06-17 2007-02-15 The Board Of Regents Of The University Of Texas System Organic/Inorganic Lewis Acid Composite Materials
US20090250252A1 (en) * 2008-04-02 2009-10-08 Nitto Denko Corporation Printed circuit board
US8330047B2 (en) * 2008-04-02 2012-12-11 Nitto Denko Corporation Printed circuit board
USRE49929E1 (en) 2017-08-08 2024-04-16 Sumitomo Electric Industries, Ltd. Substrate for high-frequency printed wiring board

Similar Documents

Publication Publication Date Title
US4849284A (en) Electrical substrate material
US5149590A (en) Electrical substrate material
US7429789B2 (en) Fluoropolymer dielectric composition for use in circuitized substrates and circuitized substrate including same
US5055342A (en) Fluorinated polymeric composition, fabrication thereof and use thereof
EP1705974A2 (en) Low moisture absorptive circuitized substrate with reduced thermal expansion, method of making same, electrical assembly utilizing same, and information handling system utilizing same
JP2009170891A (en) Improved insulating layer for rigid printed circuit boards
USRE36396E (en) Electrical substrate material comprising amorphous fused silica powder
US6692664B2 (en) Printed wiring board conductive via hole filler having metal oxide reducing capability
JP2023535549A (en) Dielectric substrate and method of forming the same
JP2007266606A (en) Fluoropolymer insulating composition for circuit board, and circuit board including same
US20120141753A1 (en) Adhesive film layer for printed circuit board applications
JP2023535759A (en) Dielectric substrate and method of forming the same
WO2022133402A1 (en) Dielectric substrate and method of forming the same
US5384181A (en) Low volume fraction ceramic filled fluoropolymeric composite material
US7931830B2 (en) Dielectric composition for use in circuitized substrates and circuitized substrate including same
WO2022133404A1 (en) Copper-clad laminate and method of forming the same
JP4462872B2 (en) Wiring board and manufacturing method thereof
US5281466A (en) Low volume fraction ceramic filled fluoropolymeric composite material
Sato et al. High performance insulating adhesive film for high-frequency applications
US6228470B1 (en) Composite substrate for electronic components
KR20220033829A (en) Printed circuit board and mehod of manufacturing thereof
JP3586792B2 (en) Fluoropolymer composites filled with low ceramic content
Kakutani et al. Reliability and High-Frequency Filter Characteristics of a Low-Loss Material for 5G RF Modules
US20230262895A1 (en) Connection structure and connection structure manufacturing method
JP2002319748A (en) Base for printed-wiring board and prepreg and printed- wiring board using the prepreg

Legal Events

Date Code Title Description
AS Assignment

Owner name: WORLD PROPERTIES, INC., ILLINOIS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ROGERS CORPORATION;REEL/FRAME:008773/0001

Effective date: 19970806

FPAY Fee payment

Year of fee payment: 12