US5727310A — Method of manufacturing a multilayer electronic c…

Claim 1

Independent Claim 275 words

A method of making a multilayer circuit board suitable for use in a transportation environment comprising the steps of: providing at least two conductive layers, each conductive layer having a conductive pattern and a plurality of contact pads defined thereon, at least one contact pad being designated an interconnecting pad, each interconnecting pad on a conductive layer having a corresponding interconnecting pad on another conductive layer, at least one conductive layer affixed to a heat resistant insulating substrate; layering an electrically interconnecting adhesive over a portion of at least one of the conductive layers to form an interconnecting layer, the interconnecting adhesive comprising a non-conductive thermosetting adhesive having a plurality of deformable conductive metallic particles dispersed substantially uniformly throughout the non-conductive adhesive such that each particle is electrically insulated from substantially every other particle, the particles and the insulating substrate of the conductive layer having substantially similar coefficients of thermal expansion, the particles having a maximum diameter that is about 90-100% of a distance between the conductive layers; aligning the conductive layers to form an uncured assembly, such that an interconnecting adhesive layer is interposed between two corresponding conductive layers with the interconnecting pads on each conductive layer aligned with their corresponding pads on the other conductive layer; and subjecting the uncured assembly to an elevated temperature and a clamping pressure to form an interconnected assembly, such that the interconnecting layer becomes conductive across a thickness thereof and non-conductive throughout a coplanar direction thereof, and such that the two conductive layers are mechanically connected in a superposed relationship with a connected distance therebetween and corresponding interconnecting pads on the two conductive layers are electrically connected.

Claim 2

Independent Claim 275 words

A method of making a multilayer circuit board suitable for use in a transportation environment comprising the steps of: providing at least two conductive layers, each conductive layer having a conductive pattern and a plurality of contact pads defined thereon, at least one contact pad being designated an interconnecting pad, each interconnecting pad on a conductive layer having a corresponding interconnecting pad on another conductive layer, at least one conductive layer affixed to a heat resistant insulating substrate; layering an electrically interconnecting adhesive over a portion of at least one of the conductive layers to form an interconnecting layer, the interconnecting adhesive comprising a non-conductive thermosetting adhesive having a plurality of deformable conductive metallic particles dispersed substantially uniformly throughout the non-conductive adhesive such that each particle is electrically insulated from substantially every other particle, the particles and the insulating substrate of the conductive layer having substantially similar coefficients of thermal expansion, the particles having a maximum diameter that is about 90-100% of a distance between the conductive layers; aligning the conductive layers to form an uncured assembly, such that an interconnecting adhesive layer is interposed between two corresponding conductive layers with the interconnecting pads on each conductive layer aligned with their corresponding pads on the other conductive layer; and subjecting the uncured assembly to an elevated temperature and a clamping pressure to form an interconnected assembly, such that the interconnecting layer becomes conductive across a thickness thereof and non-conductive throughout a coplanar direction thereof, and such that the two conductive layers are mechanically connected in a superposed relationship with a connected distance therebetween and corresponding interconnecting pads on the two conductive layers are electrically connected.

Claim 3

Dependent Claim 71 words

The method of claim 1, wherein at least one conductive layer is affixed to a heat resistant insulating substrate consisting essentially of heat resistant material capable of maintaining dimensional integrity at a temperature of at least 370° F. and at least one conductive layer is affixed to a heat sensitive substrate consisting essentially of heat sensitive material capable of maintaining dimensional integrity at a temperature of no more than 350° F.

Claim 4

Dependent Claim 29 words

The method of claim 2 wherein the heat sensitive material is selected from the group consisting of polyethylene, polypropylene, polyester, polyethylene naphthalate, as well as copolymers or combinations thereof.

Claim 5

Dependent Claim 43 words

The method of claim 1 wherein the heat resistant material is selected from the group consisting of ceramics, polyimides, polyamides, epoxy glass combinations, fluorinated alkylene polymers, polymers of fluorinated ethylene-propylene (FEP), polymers of tetrafluorethylene (TFE), phenolics, as well as copolymers or combinations thereof.

Claim 6

Dependent Claim 65 words

The method of claim 1, wherein the heat resistant insulating substrate includes an additional conductive layer affixed thereto opposite the interconnecting layer, and wherein the method further comprises the step of, after subjecting the uncured assembly to an elevated temperature and a clamping pressure, mounting an electrical device to the additional conductive layer on the heat resistant insulating substrate using a high temperature fabrication process.

Claim 7

Dependent Claim 30 words

The method of claim 5, wherein the high temperature fabrication process is selected from the group consisting essentially of soldering, infrared reflow, roll tinning, hot air leveling, or combinations thereof.

Claim 8

Dependent Claim 22 words

The method of claim 5, wherein the conductive layers affixed to the insulating substrate are interconnected by means of plated through holes.

Claim 9

Dependent Claim 29 words

The method of claim 1, wherein the interconnecting layer further comprises a second plurality of deformable conductive metallic particles having a diameter smaller than the first plurality of particles.

Claim 10

Dependent Claim 11 words

The method of claim 1, wherein the particles are substantially spherical.

Claim 11

Dependent Claim 21 words

The method of claim 1, wherein 80 percent of the particles have a diameter within 20 percent of a mean diameter.

Claim 12

Dependent Claim 24 words

The method of claim 1, wherein the particles are made of a eutectic solder comprising 63 parts of tin and 37 parts of lead.

Claim 13

Dependent Claim 28 words

The method of claim 1, wherein the particles are made of a eutectic solder comprising 62.5 parts of tin, 36.1 parts of lead and 1.4 parts of silver.

Claim 14

Dependent Claim 25 words

The method of claim 1, wherein the coefficients of thermal expansion of the particles and the insulating substrate are within 25 percent of each other.

Claim 15

Dependent Claim 15 words

The method of claim 1, wherein each conductive layer is affixed to an insulating substrate.

Claim 16

Dependent Claim 34 words

The method of claim 14, wherein the insulating substrates are 12.5 to 125 microns thick, the conductive layers are 5 to 140 microns thick, and the interconnecting layer is 15 to 100 microns thick.

Claim 17

Dependent Claim 52 words

The method of claim 1, further comprising the step of interposing an electrically insulating coverlayer between one of the conductive layers and the interconnecting layer, and having apertures defined therein corresponding to the interconnecting pads on each conductive layer, wherein the conductive layers are interconnectable only through the apertures in the coverlayer.

Claim 18

Dependent Claim 53 words

The method of claim 16, wherein the step of aligning the electrically insulating coverlayer includes the step of selecting the diameter of the apertures in the coverlayer to provide a ratio between the diameter of the apertures and the connected distance between the conductive layers that optimizes the interconnection between opposing interconnecting pads.

Claim 19

Dependent Claim 27 words

The method of claim 17, wherein the ratio between the diameter of the apertures and the connected distance between the conductive layers is about 25 to 1.

Claim 20

Dependent Claim 27 words

The method of claim 18, wherein the connected distance between the conductive layers is about 50 microns and the diameter of the apertures is about 1250 microns.

Claim 21

Independent Claim 290 words

A method of electrically connecting an electrical device to a circuit board suitable for use in a transportation environment, comprising the steps of: (a) providing a multilayer circuit board suitable for use in the transportation environment, the multilayer circuit board including: (i) first and second conductive layers, each conductive layer having a conductive pattern and a plurality of contact pads defined thereon, at least one contact pad being designated an interconnecting pad, each interconnecting pad on a conductive layer having a corresponding interconnecting pad on another conductive layer, at least one conductive layer affixed to a heat resistant insulating substrate having a third conductive layer affixed to an opposing surface of the heat resistant insulating substrate; and (ii) an electrically interconnecting adhesive layer interposed between the first and second conductive layers for mechanically connecting the first and second conductive layers in a superposed relationship with a connected distance therebetween, and for electrically connecting corresponding interconnecting pads on the first and second conductive layers, the interconnecting layer being conductive across a thickness thereof and being non-conductive throughout a coplanar direction thereof, and being disposed substantially throughout an overlapping portion of the first and second conductive layers, the interconnecting layer comprising a non-conductive adhesive having a first plurality of deformable conductive metallic particles dispersed substantially uniformly throughout the adhesive such that each particle is electrically insulated from substantially every other particle, the particles and the heat resistant insulating substrate having substantially similar coefficients of thermal expansion, and the particles having a diameter that is about 90-110% of the distance between the first and second conductive layers; and (b) electrically and mechanically connecting an electrical device to the third conductive layer on the heat resistant insulating substrate using a high temperature fabrication process.

Claim 22

Independent Claim 290 words

A method of electrically connecting an electrical device to a circuit board suitable for use in a transportation environment, comprising the steps of: (a) providing a multilayer circuit board suitable for use in the transportation environment, the multilayer circuit board including: (i) first and second conductive layers, each conductive layer having a conductive pattern and a plurality of contact pads defined thereon, at least one contact pad being designated an interconnecting pad, each interconnecting pad on a conductive layer having a corresponding interconnecting pad on another conductive layer, at least one conductive layer affixed to a heat resistant insulating substrate having a third conductive layer affixed to an opposing surface of the heat resistant insulating substrate; and (ii) an electrically interconnecting adhesive layer interposed between the first and second conductive layers for mechanically connecting the first and second conductive layers in a superposed relationship with a connected distance therebetween, and for electrically connecting corresponding interconnecting pads on the first and second conductive layers, the interconnecting layer being conductive across a thickness thereof and being non-conductive throughout a coplanar direction thereof, and being disposed substantially throughout an overlapping portion of the first and second conductive layers, the interconnecting layer comprising a non-conductive adhesive having a first plurality of deformable conductive metallic particles dispersed substantially uniformly throughout the adhesive such that each particle is electrically insulated from substantially every other particle, the particles and the heat resistant insulating substrate having substantially similar coefficients of thermal expansion, and the particles having a diameter that is about 90-110% of the distance between the first and second conductive layers; and (b) electrically and mechanically connecting an electrical device to the third conductive layer on the heat resistant insulating substrate using a high temperature fabrication process.

Claim 23

Dependent Claim 70 words

The method of claim 20, wherein the second conductive layer is affixed to a heat resistant insulating substrate consisting essentially of heat resistant material capable of maintaining dimensional integrity at a temperature of at least 370° F. and wherein the first conductive layer is affixed to a heat sensitive substrate consisting essentially of heat sensitive material capable of maintaining dimensional integrity at a temperature of no more than 350° F.

Claim 24

Dependent Claim 29 words

The method of claim 21 wherein the heat sensitive material is selected from the group consisting of polyethylene, polypropylene, polyester, polyethylene naphthalate, as well as copolymers or combinations thereof.

Claim 25

Dependent Claim 43 words

The method of claim 20 wherein the heat resistant material is selected from the group consisting of ceramics, polyimides, polyamides, epoxy glass combinations, fluorinated alkylene polymers, polymers of fluorinated ethylene-propylene (FEP), polymers of tetrafluorethylene (TFE), phenolics, as well as copolymers or combinations thereof.

Claim 26

Dependent Claim 16 words

The method of claim 20 wherein the multilayer circuit board is used in a land-based vehicle.

Claim 27

Dependent Claim 20 words

The method of claim 20 wherein the multilayer circuit board is used in an instrument panel of an automotive vehicle.

Claim 28

Dependent Claim 16 words

The method of claim 20 wherein the multilayer circuit board is used in a waterborne vehicle.

Claim 29

Dependent Claim 16 words

The method of claim 20 wherein the multilayer circuit board is used in an airborne vehicle.

Claim 30

Dependent Claim 30 words

The method of claim 20, wherein the high temperature fabrication process is selected from the group consisting essentially of soldering, infrared reflow, roll tinning, hot air leveling, or combinations thereof.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-03-16	2001-09-15	2002-03-17	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-03-16	2005-09-15	2006-03-17	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-03-16	2009-09-15	2010-03-17	$7700.00	Window Closed / Lapsed

Method of manufacturing a multilayer electronic circuit

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag