Method for making a ceramic multilayer structure having internal copper conductors

A method of making an hermetic flux-sintered ceramic multilayer element having internal copper conductors using green ceramic layers comprising finely divided particles of ceramic dielectric material and nonreducing low melting glass dispersed in a solid matrix of thermoplastic acrylic polymer binder and a thick film copper conductive paste comprising finely divided particles of copper metal dispersed in a liquid organic medium comprising a non-cellulosic polymer binder dissolved in an organic solvent which is a nonsolvent for the thermoplastic polymer binder in the green ceramic layers, comprising the sequential steps of

• a. applying a pattern of conductive paste to an unpatterned surface of a first green ceramic layer;
• b. applying an unpatterned green ceramic layer to the patterned side of the first green ceramic layer;
• c. applying a pattern of conductive paste to an unpatterned surface of a further green ceramic layer;
• d. applying the patterned side of the further green ceramic layer of step c. to an outer surface of the composite structure of step b. to form a multilayer structure comprising a plurality of conductive pattern layers sandwiched between layers of green ceramic;
• e. optionally repeating the sequence of steps c. and d., and
• f. heating the composite structure of steps d. and e. in a buffered low oxygen-containing atmosphere for a time and at a temperature sufficient completely to remove the organics without oxidizing the copper in the conductive paste.

A method of making an hermetic flux-sintered ceramic multilayer element having internal copper conductors using green ceramic layers, comprising finely divided particles of ceramic dielectric material and nonreducing low-melting glass dispersed in a solid matrix of thermoplastic acrylic polymer binder and a thick film copper conductive paste comprising finely divided particles of copper metal dispersed in a liquid organic medium comprising a non-cellulosic binder dissolved in an organic solvent which is a nonsolvent for the thermoplastic polymer binder in the green ceramic layers, comprising the sequential steps of

• a. applying a pattern of conductive paste to an unpatterned surface of a first green ceramic layer;
• b. applying an unpatterned green ceramic layer to the patterned side of the first green ceramic layer;
• c. applying a pattern of conductive paste to an unpatterned outer surface of the composite structure of step b.;
• d. applying an unpatterned green ceramic layer to a patterned outer surface of the composite structure of step c. to form a multilayer structure comprising a plurality of conductive pattern layers sandwiched between layers of green ceramic, and
• e. repeating the sequence of steps c. and d. and
• f. heating the composite structure of steps c. and d. in a buffered low oxygen-containing atmosphere for a time and at a temperature and oxygen partial pressure sufficient completely to remove the organics without oxidizing the copper in the conductive paste.

A method for making an hermetic flux-sintered ceramic multilayer element having internal copper electrodes comprising the sequential steps of:

• a. to an unpatterned surface of a first greeen ceramic layer comprised of finely divided particles of ceramic dielectric material dispersed in a solid matrix of thermoplastic acrylic polymer binder, applying a pattern of thick film conductive paste comprising finely divided particles of copper metal dispersed in a liquid organic medium comprising a non-cellulosic polymer binder dissolved in an organic solvent which is a nonsolvent for the thermoplastic polymer binder of the green ceramic tape;
• b. applying an unpatterned green ceramic layer to the patterned side of the first green ceramic layer;
• c. applying a pattern of conductive paste to an unpatterned surface of a further green ceramic layer;
• d. applying the patterned side of the further green ceramic layer of step c. to an outer surface of the composite structure of step b. to form a multilayer structure comprising a plurality of conductive pattern layers sandwiched between layers of green ceramic;
• e. optionally repeating the sequence of steps c. and d., and
• f. heating the composite structure of steps d. and e. in a buffered low oxygen-containing atmosphere for a time and at a temperature sufficient completely to remove the organics without oxidizing the copper in the conductive paste.

A method for making an hermetic flux-sintered ceramic multilayer element having internal copper electrodes comprising the sequential steps of:

• a. to an unpatterned surface of a first green ceramic layer comprised of finely divided particles of ceramic dielectric material dispersed in a solid matrix of thermoplastic acrylic polymer binder, applying a pattern of thick film conductive paste comprising finely divided particles of copper metal dispersed in a liquid organic medium comprising a non-cellulosic polymer binder dissolved in an organic solvent which is a nonsolvent for the thermoplastic polymer binder of the green ceramic tape;
• b. applying an unpatterned green ceramic layer to the patterned side of the first green ceramic layer;
• c. applying a pattern of conductive paste to an unpatterned outer surface of the composite structure of step b.;
• d. applying an unpatterned green ceramic layer to a patterned outer surface of the composite structure of step c. to form a multilayer structure comprising a plurality of conductive pattern layers sandwiched between layers of green ceramic;
• e. repeating the sequence of steps c. and d.;
• and
• f. heating the composite structure of steps c. and d. in a buffered low oxygen-containing atmosphere for a time and at a temperature and oxygen partial pressure sufficient completely to remove the organics without oxidizing the copper in the conductive paste.