Methods and structures for silver interconnections in integrated circuits

A method of making coplanar silver and insulative structures, the method comprising:

• forming a layer consisting essentially of silicon and germanium;
• forming a mask structure on the layer to define a desired metallic region and a desired insulative region;
• oxidizing the desired insulative region to form an insulative structure comprising a germanium oxide;
• removing the mask structure;
• and
• substituting silver for at least a portion of the desired metallic region, thereby forming a silver structure substantially coplanar with the insulative structure.

A method of embedding a silver structure within a structure having a reduced-dielectric constant, the method comprising:

• forming a first structure comprising an extractable material and a metal-substitutable material;
• substituting silver for at least some of the metal-substitutable material to form the silver structure;
• and
• extracting the extractable material from the first structure to form the structure having the reduced-dielectric constant.

A method of electrically connecting first and second integrated devices in an integrated-circuit assembly, the method comprising:

• forming a first layer including first and second conductive members contacting the respective first and second integrated devices;
• forming a silicon-germanium layer contacting the first and second conductive members, thereby defining first and second desired metallic regions of the silicon-germanium layer;
• and
• substituting silver for at least a portion of the silicon-germanium layer that extends from the first desired metallic region to the second desired metallic region, thereby forming a silver conductor that electrically connects the first and second integrated devices.

A via-making method that does not require etching and filling a hole in an insulative layer, the method comprising:

• forming a silicon-germanium layer on an integrated-circuit assembly;
• oxidizing a region of the silicon-germanium layer to define a desired via region;
• and
• substituting silver for at least a portion of the desired via region.

A method of making an integrated circuit, comprising:

• forming an air bridge having an air-bridge conductor;
• forming a silicon-germanium layer;
• oxidizing a region of the silicon-germanium layer to define a desired insulative region and a desired conductive region;
• and
• substituting silver for at least a portion of the desired conductive region to form a second conductive member electrically coupled to the air-bridge conductor.

A method of embedding a silver structure within a structure having a reduced-dielectric constant, the method comprising:

• forming a first structure comprising an extractable material and a metal-substitutable material;
• substituting silver for at least some of the metal-substitutable material to form the silver structure;
• and
• extracting the extractable material from the first structure to form the structure having the reduced-dielectric constant, after substituting silver for at least some of the metal-substitutable material.