Abstract: Wafers include a contact pad on a surface of a bulk redistribution layer. A final redistribution layer is formed on the surface and in contact with the contact pad. Solder is formed on the contact pad. The solder includes a pedestal portion formed to a same height as the final redistribution layer and a ball portion above the pedestal portion.

Abstract: A solder bump structure includes a pillar formed on an electrode pad. The pillar has a concave curve-shaped surface and a geometry defined at least in part by dimensions including a first height greater than a first width. The solder bump structure further includes solder formed on the concave curve-shaped surface of the pillar. The solder has a convex top surface and having dimensions including a second height greater than a second width due to the geometry of the pillar.

Abstract: Wafers include multiple bulk redistribution layers. A contact pad is formed on a surface of one of the bulk redistribution layers. A final redistribution layer is formed on the surface and in contact with the contact pad. Solder is formed on the contact pad. The solder includes a pedestal portion formed to a same height as the final redistribution layer and a ball portion above the pedestal portion.

Abstract: A method of the present invention includes preparing a substrate having a surface on which a electrode pad is formed, forming a resist layer on the substrate, the resist layer having an opening on the electrode pad, filling conductive paste in the opening of the resist layer; sintering the conductive paste in the opening to form a conductive layer which covers a side wall of the resist layer and a surface of the electrode pad in the opening, a space on the conductive layer leading to the upper end of the opening being formed, filling solder in the space on the conductive layer and removing the resist layer.

Abstract: A method for filling a through hole with solder includes mounting a substrate having a through hole formed therein on a permeable barrier layer having pores that enable gas to flow through the permeable barrier. A solder source is positioned over the through hole. Molten solder is delivered in the through hole with a positive pressure from the solder source such that gas in the through holes passes the permeable barrier while the molten solder remains in the through hole.

Abstract: A method for filling a through hole with solder includes mounting a substrate having a through hole formed therein on a permeable barrier layer having pores that enable gas to flow through the permeable barrier. A solder source is positioned over the through hole. Molten solder is delivered in the through hole with a positive pressure from the solder source such that gas in the through holes passes the permeable barrier while the molten solder remains in the through hole.

Abstract: Methods for fabricating a via structure are disclosed. In one method, fabricating the via structure includes disposing a stress buffer layer on a first surface of a substrate. The stress buffer layer has an opening aligned to a via hole of the substrate. The method further includes filling the via hole with a conductive material at least up to the first surface of the substrate. The stress buffer layer reduces stress generated due to coefficient of thermal expansion mismatch associated with the via hole and the substrate, and the conductive material extends into the opening over the level of the first surface of the substrate and/or covers, at least in part, the edge of the first surface of the substrate around the via hole.

Abstract: A via structure for electric connection is disclosed. The via structure includes a substrate that has a first surface and a via hole opened to the first surface. The via structure includes also a stress buffer layer disposed on the first surface of the substrate, which has an opening aligned to the via hole of the substrate. The via structure further includes a conductive body formed in the via hole of the substrate at least up to the level of the first surface of the substrate. In the via structure, the stress buffer layer receives the conductive body extending into the opening over the level of the first surface of the substrate and/or covers, at least in part, the edge of the first surface around the via hole of the substrate.

Abstract: A technique for fabricating bumps on a substrate is disclosed. A substrate that includes a set of pads formed on a surface thereof is prepared. A bump base is formed on each pad of the substrate. Each bump base has a tip extending outwardly from the corresponding pad. A resist layer is patterned on the substrate to have a set of holes through the resist layer. Each hole is aligned with the corresponding pad and having space configured to surround the tip of the bump base formed on the corresponding pad. The set of the holes in the resist layer is filled with conductive material to form a set of bumps on the substrate. The resist layer is stripped from the substrate with leaving the set of the bumps.

Abstract: Forming a solder joint between metal layers by preparing a structure having solder material placed between two metal layers and heating the structure to grow an intermetallic compound in a space between the two metal layers. Growing the intermetallic compound includes setting a first surface, in contact with the solder material between the two metal layers, to a first temperature, thereby enabling growth of the intermetallic compound; setting a second surface, in contact with the solder material between the two metal layers, to a second temperature, wherein the second temperature is higher than the first temperature; and maintaining a temperature gradient (temperature/unit thickness) between the two metal layers at a predetermined value or higher until the intermetallic compound substantially fills the space between the two metal layers.

Abstract: A method of forming solder bumps includes preparing a substrate having a surface on which a plurality of electrode pads are formed, forming a resist layer on the substrate, the resist layer having a plurality of openings, each of the openings being aligned with a corresponding electrode pad of the plurality of electrode pads, forming a conductive pillar in each of the openings of the resist layer, forming conductive layers to cover at least side walls of the resist layer in the openings to block gas emanating from the resist layer, filling molten solder in each of the openings in which the conductive layers has been formed and removing the resist layer.

Abstract: A method of forming solder bumps includes preparing a substrate having a surface on which a plurality of electrode pads are formed, forming a resist layer on the substrate, the resist layer having a plurality of openings, each of the openings being aligned with a corresponding electrode pad of the plurality of electrode pads, forming a conductive pillar in each of the openings of the resist layer, forming conductive layers to cover at least side walls of the resist layer in the openings to block gas emanating from the resist layer, filling molten solder in each of the openings in which the conductive layers has been formed and removing the resist layer.

Abstract: Wafers and methods of forming solder balls include etching a hole in a final redistribution layer over a terminal contact pad on a wafer to expose the terminal contact pad. Solder is injected into the hole using an injection nozzle that is in direct contact with the final redistribution layer. The final redistribution layer is etched back. The injected solder is reflowed to form a solder ball.

Abstract: A via structure for electric connection is disclosed. The via structure includes a substrate that has a first surface and a via hole opened to the first surface. The via structure includes also a stress buffer layer disposed on the first surface of the substrate, which has an opening aligned to the via hole of the substrate. The via structure further includes a conductive body formed in the via hole of the substrate at least up to the level of the first surface of the substrate. In the via structure, the stress buffer layer receives the conductive body extending into the opening over the level of the first surface of the substrate and/or covers, at least in part, the edge of the first surface around the via hole of the substrate.

Abstract: A via structure for electric connection is disclosed. The via structure includes a substrate that has a first surface and a via hole opened to the first surface. The via structure includes also a stress buffer layer disposed on the first surface of the substrate, which has an opening aligned to the via hole of the substrate. The via structure further includes a conductive body formed in the via hole of the substrate at least up to the level of the first surface of the substrate. In the via structure, the stress buffer layer receives the conductive body extending into the opening over the level of the first surface of the substrate and/or covers, at least in part, the edge of the first surface around the via hole of the substrate.

Abstract: A joined structure which is configured such that a space between adjacent substrates is filled with a filling material. The joined structure includes a first substrate having a first conductor formed on a surface of the first substrate, a second substrate having a second conductor formed on a surface of the second substrate, arranged so that a surface of the first substrate faces a surface of the second substrate, a connecting conductor which electrically connects the first conductor and the second conductor, and a filling material between the first substrate and the second substrate. The filling material is formed into such a shape that a space is provided which corresponds to at least one of the first conductor, the second and the connecting conductor.

Abstract: Methods for depositing material on a chip include forming a mold layer. The mold layer includes one or more openings over respective contact areas, each of the one or more openings having an upper volume and a lower volume. The upper volume has a smaller diameter than a diameter of the lower volume. Each contact area is within the respective lower volume. A material is injected into the one or more openings under pressure.

Abstract: Wafers include multiple bulk redistribution layers. A contact pad is formed on a surface of one of the bulk redistribution layers. A final redistribution layer is formed on the surface and in contact with the contact pad. Solder is formed on the contact pad. The solder includes a pedestal portion formed to a same height as the final redistribution layer and a ball portion above the pedestal portion.

Abstract: Methods for depositing material on a chip include forming a mold layer on a substrate. The mold layer has one or more openings over respective contact areas on the substrate. The one or more openings are formed from an upper volume and a lower volume, the upper volume having a smaller diameter than a diameter of the lower volume. A material is injected into the one or more openings under pressure, such that gas trapped in the one or more openings displaces into the lower volume until the injected material in the one or more openings makes contact with each respective contact area.

Abstract: Wafers include multiple bulk redistribution layers. A terminal contact pad is on a surface of one of the bulk redistribution layers. A final redistribution layer is formed on the surface and in contact with the terminal contact pad. The final redistribution layer is formed from a material other than a material of the plurality of bulk redistribution layers. A solder ball is formed on the terminal contact pad.