Method for preparing ceramic tape compositions

Claim 1

A method for making a dielectric sheet composition having a low dielectric constant and a high hermeticity comprising the steps of: (a) mixing a glass powder having an average particle size in the range of 0.3 to 50 μm with a volatile, organic solvent containing an organic polymer binder and an organic plasticizer to form a uniform dispersion; (b) milling the dispersion to pulverize and uniformly disperse the glass component; (c) dispersing ceramic hollow microspheres having a particle size in the range of 10-200 μm at high speed into the milled dispersion to form a slip having a viscosity in the range of 500-1500 cps; (d) deareating the slip and casting a thin layer thereof onto a flexible substrate forming a sheet within one hour of final mixing and heating the cast layer until solvent has been removed; and (e) removing the sheet fromm the substrate and firing it to remove organic material and then sintering the sheet.

Claim 2

A method for making a dielectric sheet composition having a low dielectric constant and a high hermeticity comprising the steps of: (a) mixing a glass powder having an average particle size in the range of 0.3 to 50 μm with a volatile, organic solvent containing an organic polymer binder and an organic plasticizer to form a uniform dispersion; (b) milling the dispersion to pulverize and uniformly disperse the glass component; (c) dispersing ceramic hollow microspheres having a particle size in the range of 10-200 μm at high speed into the milled dispersion to form a slip having a viscosity in the range of 500-1500 cps; (d) deareating the slip and casting a thin layer thereof onto a flexible substrate forming a sheet within one hour of final mixing and heating the cast layer until solvent has been removed; and (e) removing the sheet fromm the substrate and firing it to remove organic material and then sintering the sheet.

Claim 3

A method for making a dielectric sheet composition having a dielectric constant in the range of 3 to 5.5 at 1 MHz and a density greater than 93% of theoretical comprising the steps of: (a) mixing a glass powder having an average particle size in the range of 1 to 50 μm, in an amount sufficient to constitute 50 to 95 vol. % of the dielectric composition, with a volatile, non-aqueous organic solvent polymeric binder comprising 5 to 20% by weight of the mixture and 10 to 50% by weight based on the polymeric binder of an organic plasticizer; (b) milling the mixture for 1 to 2 hours to pulverize and uniformly disperse the glass component; (c) adding ceramic hollow microspheres having a particle size in the range of 10 to 200 μm, in an amount sufficient to constitute 10 to 50 vol. % of the dielectric composition, and dispersing them at high speed to form a slip having a viscosity in the range of 500 to 1500 cps; (d) deaerating the slip and within one hour of final mixing casting a thin layer thereof having a thickness variation of not more than ±2% onto a flexible substrate to form a sheet, and heating the cast sheet at 20° to 50° C. to remove the solvent; (e) removing the sheet from the substrate and heating it in an oxidizing atmosphere at 300° to 500° C. to remove organic material and thereafter sintering the sheet by raising its temperature to 800° to 950° C. for at least 30 minutes.

Claim 4

A method for making a dielectric sheet composition having a dielectric constant in the range of 3 to 5.5 at 1 MHz and a density greater than 93% of theoretical comprising the steps of: (a) mixing a glass powder having an average particle size in the range of 1 to 50 μm, in an amount sufficient to constitute 50 to 95 vol. % of the dielectric composition, with a volatile, non-aqueous organic solvent polymeric binder comprising 5 to 20% by weight of the mixture and 10 to 50% by weight based on the polymeric binder of an organic plasticizer; (b) milling the mixture for 1 to 2 hours to pulverize and uniformly disperse the glass component; (c) adding ceramic hollow microspheres having a particle size in the range of 10 to 200 μm, in an amount sufficient to constitute 10 to 50 vol. % of the dielectric composition, and dispersing them at high speed to form a slip having a viscosity in the range of 500 to 1500 cps; (d) deaerating the slip and within one hour of final mixing casting a thin layer thereof having a thickness variation of not more than ±2% onto a flexible substrate to form a sheet, and heating the cast sheet at 20° to 50° C. to remove the solvent; (e) removing the sheet from the substrate and heating it in an oxidizing atmosphere at 300° to 500° C. to remove organic material and thereafter sintering the sheet by raising its temperature to 800° to 950° C. for at least 30 minutes.