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.

A microelectronic device is formed by forming a platinum-containing layer on a substrate of the microelectronic device. A cap layer is formed on the platinum-containing layer so that an interface between the cap layer and the platinum-containing layer is free of platinum oxide. The cap layer is etchable in an etch solution which also etches the platinum-containing layer. The cap layer may be formed on the platinum-containing layer before platinum oxide forms on the platinum-containing layer. Alternatively, platinum oxide on the platinum-containing layer may be removed before forming the cap layer. The platinum-containing layer may be used to form platinum silicide. The platinum-containing layer may be patterned by forming a hard mask or masking platinum oxide on a portion of the top surface of the platinum-containing layer to block the wet etchant.

A microelectronic device is formed by forming a platinum-containing layer on a substrate of the microelectronic device. A cap layer is formed on the platinum-containing layer so that an interface between the cap layer and the platinum-containing layer is free of platinum oxide. The cap layer is etchable in an etch solution which also etches the platinum-containing layer. The cap layer may be formed on the platinum-containing layer before platinum oxide forms on the platinum-containing layer. Alternatively, platinum oxide on the platinum-containing layer may be removed before forming the cap layer. The platinum-containing layer may be used to form platinum silicide. The platinum-containing layer may be patterned by forming a hard mask or masking platinum oxide on a portion of the top surface of the platinum-containing layer to block the wet etchant.

The present disclosure discloses a fabrication method for wafer-level packaging, comprising: forming a first photoresist on a first chip and a plurality of first openings at the first photoresist to expose a functional surface of the first chip, forming an under-bump metal layer on the functional surface exposed through the plurality of first openings, and removing the first photoresist; connecting a functional solder bump of a second chip to the under-bump metal layer on the first chip; forming a filling layer between the first chip, and the second chip; and forming a connecting member on the first chip, wherein a solder ball is disposed at a top surface of the connecting member, and an apex of the solder ball is higher than a top surface of the second chip.

The present disclosure discloses a fabrication method for wafer-level packaging, comprising: forming a first photoresist on a first chip and a plurality of first openings at the first photoresist to expose a functional surface of the first chip, forming an under-bump metal layer on the functional surface exposed through the plurality of first openings, and removing the first photoresist; connecting a functional solder bump of a second chip to the under-bump metal layer on the first chip; forming a filling layer between the first chip, and the second chip; and forming a connecting member on the first chip, wherein a solder ball is disposed at a top surface of the connecting member, and an apex of the solder ball is higher than a top surface of the second chip.

A method includes forming a first conductive feature and a second conductive feature, forming a metal pad over and electrically connected to the first conductive feature, and forming a passivation layer covering edge portions of the metal pad, with a center portion of a top surface of the metal pad exposed through an opening in the metal pad. A first dielectric layer is formed to cover the metal pad and the passivation layer. A bond pad is formed over the first dielectric layer, and the bond pad is electrically coupled to the second conductive feature. A second dielectric layer is deposited to encircle the bond pad. A planarization is performed to level a top surface of the second dielectric layer with the bond pad. At a time after the planarization is performed, an entirety of the top surface of the metal pad is in contact with dielectric materials.

The present technology is directed to manufacturing semiconductor dies with under-bump metal (UBM) structures for die-to-die and/or package-to-package interconnects or other types of interconnects. In one embodiment, a method for forming under-bump metal (UBM) structures on a semiconductor die comprises constructing a UBM pillar by plating a first material onto first areas of a seed structure and depositing a second material over the first material. The first material has first electrical potential and the second material has a second electrical potential greater than the first electrical potential. The method further comprises reducing the difference in the electrical potential between the first material and the second material, and then removing second areas of the seed structure between the UBM pillars thereby forming UBM structures on the semiconductor die.

The present technology is directed to manufacturing semiconductor dies with under-bump metal (UBM) structures for die-to-die and/or package-to-package interconnects or other types of interconnects. In one embodiment, a method for forming under-bump metal (UBM) structures on a semiconductor die comprises constructing a UBM pillar by plating a first material onto first areas of a seed structure and depositing a second material over the first material. The first material has first electrical potential and the second material has a second electrical potential greater than the first electrical potential. The method further comprises reducing the difference in the electrical potential between the first material and the second material, and then removing second areas of the seed structure between the UBM pillars thereby forming UBM structures on the semiconductor die.

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.

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.