TH48784A - Power and earthing planes with low CTEs - Google Patents

Abstract

DC60 (10/11/43) Conductive materials with a low coefficient of thermal expansion (CTE), used for power planes and ground planes, have been revealed. Fibrous materials (e.g., carbon, graphite, glass, quartz crystals, polyethylene, and liquid crystal polymer fibers) with low CTE are metallized to provide a resulting low CTE conductive material. These fibers may be metallized in their specific states and then fabricated, or they may be fabricated and then metallized, or a combination of both metallization methods may be used. In addition, thin sheets of graphite or carbon may be metallized on one or both sides to provide a low CTE and high conductivity material. These metallized low CTE power planes and ground planes may be stacked against other planes/axis to form composite materials or stacked individually. It is a core which is then stacked and compressed with other planes/axis to form a composite material. The resulting composite material can be used for printed circuit boards (PCBs), or PCBs used as a stacked, compressed chip support. Conductive materials with a low coefficient of thermal expansion (CTE), which are used for the power plane and ground plane, have been exposed. Fibrous materials (such as carbon, graphite, glass, quartz crystals, polyethylene, and liquid crystal polymer fibers) with low CTE are metallized to provide a resulting low CTE conductive material. These types of fibers may be metallized in their specific states and then fabricated, or these materials may be fabricated and then metallized, or a combination of both metallization methods may be used. In addition, thin sheets of graphite or carbon may be metallized on one or both sides to provide a low CTE material and high conductivity. These metallized low CTE power planes and ground planes may be stacked. Compressed with other planes/axis to form a composite, or stacked and compressed to form a core which is then stacked and compressed with other planes/axis to form a composite material. The resulting composite material can then be used for printed circuit boards (PCBs), where the PCB serves as the support for stacked, compressed chips.

Claims (34)

1. Power core/grounding core for use in printed circuit boards (PCBs). The power core/grounding core consists of the following components: at least one layer of compressed fibrous laminated material and at least one layer of conductive material, where the conductive material has a coefficient of thermal expansion (CTE) lower than the CTE of the copper plane. 2. Power/Grounding Core as specified in Claim 1, where at least one conductive layer is made of two conductive layers, with at least one fibrous compressed layer clamped between the two conductive layers. 3. Power/Grounding Core as specified in Claim 1, where at least one layer of fibrous composite sheet shall be a double fibrous composite sheet, and at least one layer of conductive material shall be clamped between the two layers of fibrous composite sheets. 4. Power core/grounding core as specified in Claim 1, which has at least one non-conductive fibrous compressed layer. 5. Power core/grounding core as specified in Claim 1, which has at least one layer of compressed fibrous material that is electrically conductive. 6. Power core/grounding core as specified in Claim 1, where the CTE of the conductive material is less than 5 PPM/C. 7. Power core/grounding core, as specified in Claim 1, where the conductive material consists of carbon encased in a thin layer of metal or graphite. 8. Power/Grounding Core as specified in Claim 1, where the conductive material consists of a metallic fibrous material woven into a sheet or formed into a sheet of irregularly arranged paper. 9. Power core/grounding core, as specified in claim 8, where the fibrous material shall be selected from a group comprising carbon fibers, graphite fibers, liquid crystal polymer fibers, polyethylene fibers, quartz fibers, and glass fibers. 10. The power core/grounding core, as specified in Cladding 1, shall consist of at least one layer of fibrous composite sheet selected from a group comprising epoxy, bismaleimid, triazine epoxy, cyanate ester, polyimide, polytetrafluoroethylene (PTFE), polytetrafluoroethylene and fluoropolymer. 11. A printed circuit board (PCB) consisting of the following components: at least one signal core, each consisting of at least one signal layer and at least one layer of fibrous laminated sheet; and at least one power/grounding core, consisting of at least one layer of fibrous laminated sheet and at least one layer of conductive material, where the conductive material has a coefficient of thermal expansion (CTE) lower than the CTE of the copper plane. 12. A PCB as defined in Claim 11 shall have at least one conductive layer, and at least one filament-filled layer of a power core/grounding core shall be clamped between the two conductive layers. 13. A PCB as defined in Claim 11 shall have at least one layer of fibrous laminated board of at least one power core/grounding core, which shall be two fibrous laminated board layers, with at least one layer of conductive material clamped between the two fibrous laminated board layers. 14. The PCB, as specified in Claim 11, has at least one compressed layer of power core/grounding core that is non-conductive. 15. A PCB as specified in Claim 11, which has at least one compressed layer of a power core/grounding core that is conductive. 16. PCB as specified in Claim 11, where the CTE of the conductive material is less than 5 PPM/C. 17. A PCB as defined in claim 11, in which the conductive material consists of carbon encased in a thin layer of metal or graphite. 18. A PCB, as defined in claim 11, where the conductive material consists of a metallic fibrous material woven or formed into a sheet with an irregular arrangement. 19. PCBs, as specified in claim 18, where fibrous materials are selected from a group comprising carbon fiber, graphite fiber, liquid crystal polymer fiber, polyethylene fiber, quartz fiber, and glass fiber. 20. The PCB, as specified in Claim 11, shall consist of at least one thin-layer material layer and at least one power core/grounding core selected from a group of materials including epoxy, bismaleimid triazine epoxy, cyanate ester, polyimide, polytetrafluoroethylene (PTFE), polytetrafluoroethylene and fluoropolymer. 21. The manufacturing process of a printed circuit board (PCB) involves the following assembly steps: a) Providing at least one power/grounding plane consisting of at least one layer of conductive material, where the conductive material has a CTE lower than the CTE of the copper plane; b) Creating a number of openings in at least one power/grounding plane; c) Creating a composite material in at least one power/grounding plane and at least one signal layer; d) Creating a number of openings in the composite material; e) Creating a number of metal-plated through holes in the composite material. 22. The procedure specified in Claim 21, which provides at least one power/grounding plane, shall include a procedure for forming a power/grounding core with at least one layer of compressed fibrous sheet and at least one layer of a low CTE conductive material. 23. The method as specified in Claim 22, in which at least one layer of fibrous compressed sheet of the power core/grounding core is selected from a group comprising epoxy, bismaleimid triazine epoxy, cyanate ester, polyimide, polytetrafluoroethylene (PTFE), polytetrafluoroethylene and fluoropolymer. 24. The method of claim 22, in which at least one layer of conductive material shall be a layer of two conductive materials, and in which the power core/grounding core forming procedure shall consist of a procedure of clamping across at least one layer of fibrous compressed sheet between two layers of conductive material. 25. The method described in Claim 24, which involves clamping over a layer of at least one fibrous laminated sheet between two layers of conductive material, consists of a process of encapsulating at least one layer of conductive material using an saturation process and laminating the conductive material encapsulated in a release sheet or a thin, coarsely ground copper sheet. 26. The method specified in Claim 22, in which at least one layer of fibrous composite sheet shall be a double fibrous composite sheet, and in which the forming procedure of the power core/grounding core shall consist of clamping over at least one layer of conductive material between the two layers of fibrous composite sheet. 27. Power core/grounding core as specified in Claim 22, where at least one layer of compressed fibrous sheet is non-conductive. 28. Power core/grounding core as specified in Claim 22, where at least one layer of compressed fibrous sheet is conductive. 29. The method described in claim 21 still includes an additional step of coating the electrically conductive material with a metal. 30. The method specified in claim 21, which still comprises the operational steps and processes that facilitate adhesion to electrically conductive materials with a low CTE. 31. The methods specified in Claim 30, in which the bonding process is aided, shall be copper oxide treatment or silane treatment. 32. The method described in Claim 21, in which a low CTE conductive material is made of metal-coated carbon or thin graphite sheets. 33. The method described in Claim 21, in which the electrically conductive material is made up of a metallic fibrous material woven into a sheet or formed into a sheet of paper with an irregular arrangement. 34. The method as specified in claim 33 shall be used, in which fibrous materials shall be selected from a group comprising carbon fibers, graphite fibers, liquid crystal polymer fibers, polyethylene fibers, quartz fibers and glass fibers.