Method for preparing a chip scale package and product produced by the method

A method of preparing a chip scale package for microelectronic devices having a connection surface with a plurality of exposed interconnect pads, comprising:

• providing solder jetting means for jetting droplets of solder through a protective atmosphere toward the interconnect pads on the connection surface;
• building a column of solder on each pad from drops jetted from the solder jetting means toward the interconnect pads, said columns having a height extending away from the interconnect pads to about the same height;
• covering the connection surface with a layer of dielectric to a thickness greater than the height of the solder columns;
• removing enough of the layer of dielectric material on the connection surface to expose the outer ends of the solder columns;
• and
• converting the outer end of each solder column to a bump to serve as the basis of an electrical connection with another device.

The method of preparing a chip scale package, comprising:

• providing a microelectronic device having a connection surface with a multiplicity of exposed interconnect pads;
• providing solder jetting means for jetting droplets of molten solder through a protective atmosphere toward individual interconnect pads on the connection surface;
• applying a layer of dielectric material over the connection surface;
• creating blind ended vias over said interconnect pads;
• and
• operating said jetting means to create solder columns by jetting molten solder into said vias.

Method of preparing an electronic solder column interconnection, comprising the steps of:

• providing an electronic device having a plurality of interconnect pads on a connection surface covered iwth a layer of dielectric material and a plurality of vias within the dielectric layer exposing the intrconnect pads;
• providing solder jetting means for jetting droplets of molten solder through a protective atmosphere toward the vias;
• and
• operating said jetting means to create solder columns on the interconnect pads by jetting molten solder droplets into said vias.

A method of preparing a chip scale package, comprising:

• providing a wafer having therein a plurality of microelectronic devices each having a connection surface and a multiplicity of exposed interconnect pads;
• providing a solder jetting means for jetting droplets of molten solder through a protective atmosphere toward individual interconnect pads;
• operating said jetting means to direct droplets of molten solder toward one individual pad;
• building a column of solder to a desired height on said one individual pad by depositing and freezing one or more successive droplets on said one individual pad and then successively depositing additional droplets on previously deposited droplets whereby said pad can be electrically connected at a distance through a connection to said column;
• stepping the solder jetting means with respect to the microelectronic devices to direct droplets of molten solder toward successive individual pads;
• building a column of solder to the desired height on successive individual pads by depositing and freezing successive droplets of solder thereon;
• and
• applying a dielectric layer to each microelectronic device surrounding said columns.

A method of making a microelectronic package having multiple electrical interconnections, comprising:

• providing a connection surface having a multiplicity of exposed electrical interconnect pads for an integrated circuit chip;
• providing a first operable solder jet printhead capable of jetting drops of molten solder on demand;
• providing a second operable solder jet printhead capable of jetting drops of dielectric material on demand;
• aiming the output of said first printhead toward a selected first pad on the connection surface;
• building a column of solidified solder drops upon said first pad, by operating said first printhead, said column extending away from the connection surface;
• aiming the output of said first printhead toward successive selected pads on the connection surface and building a column of solidified solder drops extending away from the connection surface upon successive pads wherein said columns are all about an equal height above the connection surface;
• aiming the output of said second printhead toward the connection surface;
• building a protective layer of dielectric material on the connection surface by operating the second printhead and creating relative movement between the connection surface and the printhead until the columns of solidified solder are covered with the dielectric;
• removing part of the dielectric to expose the top of the columns of solder;
• and
• converting the top of each solder column to a bump in readiness for a solder reflow operation whereby electrical leads are connected to the interconnect pads through said solder columns.