Freescale Semiconductor,inc.

Eddie Acosta

Varughese Mathew

Sam S Garcia

Ritwik Chatterjee

A method for forming a via, comprising (a) providing a structure comprising a mask () disposed on a semiconductor substrate (), wherein the structure has an opening () defined therein which extends through the mask and into the substrate, and wherein the mask comprises a first electrically conductive layer; (b) depositing a second electrically conductive layer () such that the second conductive layer is in electrical contact with the first conductive layer, the second conductive layer having a first portion which extends over the surfaces of the opening and a second portion which extends over a portion of the mask adjacent to the opening; (c) removing the second portion of the second conductive layer; and (d) depositing a first metal () over the first portion of the second conductive layer.

Method to form a via

A method for forming an interconnect, comprising (a) providing a substrate () with a via () defined therein; (b) forming a seed layer () such that a first portion of the seed layer extends over a surface of the via, and a second portion of the seed layer extends over a portion of the substrate; (c) removing the second portion of the seed layer; and (d) depositing a metal () over the first portion of the seed layer by an electroless process.

Method for forming interconnects for 3-D applications

A method forms a micropad to an external contact of a first semiconductor device. A stud of copper is formed over the external contact. The stud extends above a surface of the first semiconductor device. The stud of copper is immersed in a solution of tin. The tin replaces at least 95 percent of the copper of the stud and preferably more than 99 percent. The result is a tin micropad that has less than 5 percent copper by weight. Since the micropad is substantially pure tin, intermetallic bonds will not form during the time while the micropads of the first semiconductor device are not bonded. Smaller micropad dimensions result since intermetallic bonds do not form. When the first semiconductor device is bonded to an overlying second semiconductor device, the bond dimensions do not significantly increase the height of stacked chips.

Micropad formation for a semiconductor

A semiconductor process is taught for performing electroless plating of copper overlying at least a portion of a layer comprising cobalt, nickel, or both cobalt and nickel. The cobalt and/or nickel comprising layer may be formed using electroless plating. For some embodiments, a tin layer is then formed overlying the copper. The tin layer may be formed using immersion plating or electroless plating. A micropad may comprise the cobalt and/or nickel comprising layer and the copper layer. In some embodiments, the micropad may also comprise the tin layer. In one embodiment, the micropad may be compressed at an elevated temperature to form a copper tin intermetallic compound which provides an interconnect between a plurality of semiconductor devices.

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Martindale, TX, United States of America

Eddie Acosta