Abstract: The present invention discloses a method and apparatus for forming solder bumps by a molten solder screening technique in which a flexible die head constructed of a metal sheet is utilized for maintaining an intimate contact between the die head and a solder receiving mold surface. The flexible die head, when used in combination with a pressure means, is capable of conforming to any curved mold surface as long as the curvature is not more than 2.5 &mgr;m per inch of die length.

Abstract: The present invention discloses a method and apparatus for forming solder bumps by a molten solder screening technique in which a flexible die head constructed of a metal sheet is utilized for maintaining an intimate contact between the die head and a solder receiving mold surface, The flexible die head, when used in combination with a pressure means, is capable of conforming to any curved mold surface as long as the curvature is not more than 2.5 &mgr;m per inch of die length. The present invention further provides a method and apparatus for filling a multiplicity of cavities in a mold surface by providing a stream of molten solder and then intimately contacting the surface of the molten solder with a multiplicity of cavities such that the molten solder readily fills the cavities. The apparatus further provides means for removing excess molten solder from the surface of the mold without disturbing the molten solder already filled in the cavities.

Abstract: A method of forming interconnects on an electronic device that can be bonded to another electronic device at a low processing temperature can be carried out by depositing a first interconnect material on the electronic device forming protrusions and then depositing a second interconnect material to at least partially cover the protrusions, wherein the second interconnect material has a lower flow temperature than the first interconnect material. The method is carried out by flowing a molten solder into a mold having microcavities to fill the cavities and then allowed to solidify. The mold is then aligned with a silicon wafer containing chips deposited with high melting temperatures solder bumps such that each microcavity of the mold is aligned with each high melting temperature solder bump on the chip.

Abstract: A method for forming solder bumps on an electronic structure including the steps of first providing a mold made by a sheet of a mold material having a thickness greater than that of the solder bumps to be formed, the mold material has sufficient optical transparency so as to allow the inspection of a solder material subsequently filled into the mold cavities that are formed in the mold material, and a coefficient of thermal expansion that is substantially similar to the substrate which the mold will be mated to, forming a multiplicity of mold cavities in the sheet of mold material, filling the multiplicity of mold cavities with a solder material, cooling the mold to a temperature that is sufficient to solidify the solder material in the multiplicity of mold cavities, positioning the mold intimately with the electronic structure such that the cavities facing the structure, and heating the mold and the structure together to a temperature sufficiently high such that the solder material transfers onto the electro

Abstract: A method for forming solder bumps on an electronic structure including the steps of first providing a mold made by a sheet of a mold material having a thickness greater than that of the solder bumps to be formed, the mold material has sufficient optical transparency so as to allow the inspection of a solder material subsequently filled into the mold cavities that are formed in the mold material, and a coefficient of thermal expansion that is substantially similar to the substrate which the mold will be mated to, forming a multiplicity of mold cavities in the sheet of mold material, filling the multiplicity of mold cavities with a solder material, cooling the mold to a temperature that is sufficient to solidify the solder material in the multiplicity of mold cavities, positioning the mold intimately with the electronic structure such that the cavities facing the structure, and heating the mold and the structure together to a temperature sufficiently high such that the solder material transfers onto the electro

Abstract: A method of forming interconnects on an electronic device that can be bonded to another electronic device at a low processing temperature can be carried out by depositing a first interconnect material on the electronic device forming protrusions and then depositing a second interconnect material to at least partially cover the protrusions, wherein the second interconnect material has a lower flow temperature than the first interconnect material. The method is carried out by flowing a molten solder into a mold having microcavities to fill the cavities and then allowed to solidify. The mold is then aligned with a silicon wafer containing chips deposited with high melting temperatures solder bumps such that each microcavity of the mold is aligned with each high melting temperature solder bump on the chip.

Abstract: The present invention discloses a method and apparatus for forming solder bumps by a molten solder screening technique in which a flexible die head constructed of a metal sheet is utilized for maintaining an intimate contact between the die head and a solder receiving mold surface. The flexible die head, when used in combination with a pressure means, is capable of conforming to any curved mold surface as long as the curvature is not more than 2.5 .mu.m per inch of die length. The present invention further provides a method and apparatus for filling a multiplicity of cavities in a mold surface by providing a stream of molten solder and then intimately contacting the surface of the molten solder with a multiplicity of cavities such that the molten solder readily fills the cavities. The apparatus further provides means for removing excess molten solder from the surface of the mold without disturbing the molten solder already filled in the cavities.

Abstract: An apparatus and a method for transferring solder bumps from a solder mold to a solder-receiving substrate are disclosed. The apparatus includes a transfer fixture constructed by a base member, a lid member and a compressible member for holding a mold/substrate assembly therein. A plurality of compression pins are mounted through the lid member for supplying a uniform pressure on the mold/substrate assembly and for allowing lateral motion of the mold/substrate assembly relative to the transfer fixture due to a mismatch in the coefficients of thermal expansion. The compressible member is a cellulosic foam sheet which applies a uniform joining force across the entire surface of a wafer and assures abutting contact between the entire wafer and the mold surface. The foam sheet further assists in the lateral movement of the mold/substrate assembly relative to the base member of the transfer fixture.

Abstract: An interconnect system that has low alpha particle emission characteristics for use in an electronic device includes a semiconductor chip that has an upper surface and spaced apart electrically resistive bumps positioned on conductive regions of the upper surface, the electrically resistive bumps are made of a composite material of a polymer and metal particles, and a substrate that has conductive regions bonded to the electrically resistive bumps in a bonding process wherein the electrically resistive bumps convert to electrically conductive bumps after the bonding process.

Abstract: A method for forming solder bumps on an electronic structure including the steps of first providing a mold made by a sheet of a mold material having a thickness greater than that of the solder bumps to be formed, the mold material has sufficient optical transparency so as to allow the inspection of a solder material subsequently filled into the mold cavities that are formed in the mold material, and a coefficient of thermal expansion that is substantially similar to the substrate which the mold will be mated to, forming a multiplicity of mold cavities in the sheet of mold material, filling the multiplicity of mold cavities with a solder material, cooling the mold to a temperature that is sufficient to solidify the solder material in the multiplicity of mold cavities, positioning the mold intimately with the electronic structure such that the cavities facing the structure, and heating the mold and the structure together to a temperature sufficiently high such that the solder material transfers onto the electro