A method of manufacturing a multi-layer wafer is provided. Under bump metallization (UMB) pads are created on each of two heterogeneous wafers. A conductive means is applied above the UMB pads on at least one of the two heterogeneous wafers. The two heterogeneous wafers are low temperature bonded to adhere the UMB pads together via the conductive means. At least one stress compensating polymer layer may be applied to at least one of two heterogeneous wafers. The stress compensating polymer layer has a polymer composition of a molecular weight polymethylmethacrylate polymer at a level of 10-50% with added liquid multifunctional acrylates forming the remaining 50-90% of the polymer composition.

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.

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.

A method for fabricating a resist structure is presented. The method includes preparing a substrate on which plural conductive pads are formed; and patterning a lower resist to form plural lower cavities. The lower resist is deposited above the substrate. Each of the plural lower cavities are located above a corresponding one of the plural conductive pads. Additionally, the method includes patterning an upper resist to form plural upper cavities. The upper resist is deposited on the lower resist. Each of the plural upper cavities are located on a corresponding one of the plural lower cavities and have a diameter larger than a diameter of the corresponding one of the plural lower cavities.

An electroplating method that is a conventional method has had a problem that it is difficult to manufacture fine pillars without being affected by an undercut. Furthermore, an electroless plating method has had a problem that it is difficult to manufacture pillars having the same shape without any void. The inventors have performed intensive investigations to solve the above problems and, as a result, have found that fine conductive pillars with a high aspect ratio can be readily manufactured on a substrate having an electrode section in such a manner that after a conductive paste containing metal micro-particles is applied in a reduced pressure state, the conductive paste is exposed to standard pressure. The present invention has a particular effect on the manufacture of a metal pillar that is a terminal for flip-chip mounting.

An electroplating method that is a conventional method has had a problem that it is difficult to manufacture fine pillars without being affected by an undercut. Furthermore, an electroless plating method has had a problem that it is difficult to manufacture pillars having the same shape without any void. The inventors have performed intensive investigations to solve the above problems and, as a result, have found that fine conductive pillars with a high aspect ratio can be readily manufactured on a substrate having an electrode section in such a manner that after a conductive paste containing metal micro-particles is applied in a reduced pressure state, the conductive paste is exposed to standard pressure. The present invention has a particular effect on the manufacture of a metal pillar that is a terminal for flip-chip mounting.

A method for fabricating a resist structure is presented. The method includes preparing a substrate on which plural conductive pads are formed; and patterning a lower resist to form plural lower cavities. The lower resist is deposited above the substrate. Each of the plural lower cavities are located above a corresponding one of the plural conductive pads. Additionally, the method includes patterning an upper resist to form plural upper cavities. The upper resist is deposited on the lower resist. Each of the plural upper cavities are located on a corresponding one of the plural lower cavities and have a diameter larger than a diameter of the corresponding one of the plural lower cavities.

A semiconductor device includes a substrate having a plurality of pads on a surface of the substrate, a semiconductor chip that includes a plurality of metal bumps connected to corresponding pads on the substrate, a first resin layer between the surface of the substrate and the semiconductor chip, a second resin layer between the substrate and the semiconductor chip and between the first resin layer and at least one of the metal bumps, and a third resin layer on the substrate and above the semiconductor chip.

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.

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.