Thinning tungsten layer after through silicon via filling

A method of processing a partially manufactured semiconductor substrate, the method comprising:

• providing the substrate with one or more through silicon vias filled with tungsten and an initial tungsten layer formed on a field region of the substrate during filling of the one or more through silicon vias, wherein the substrate is a 300-mm wafer and at least one of the one or more through silicon vias has an aspect ratio of greater than about 10 and an opening diameter of at least about 1 micrometer, and wherein the initial tungsten layer extends above and adjacent to the one or more through silicon vias substantially covering the field region of the substrate and has an intrinsic residual stress that causes an interior portion of the substrate to deviate from a plane defined by edges of the substrate;
• exposing the field region of the substrate to an etchant, wherein the etchant comprising activated fluorine species;
• and
• removing a part of the initial tungsten layer to form an etched tungsten layer substantially covering the field region of the substrate and the one or more through silicon vias such that the through silicon vias remain filled, wherein the average thickness of the etched tungsten layer is at least twice less than the average thickness of the initial tungsten layer, and wherein the etched layer has an intrinsic residual stress that is less than the intrinsic residual stress of the initial tungsten layer such that the deviation of the substrate from the plane is reduced after forming the etched tungsten layer.

A semiconductor processing apparatus for processing a partially manufactured semiconductor substrate, the apparatus comprising:

• a processing chamber having a layer processing station for positing the substrate;
• a heating element configured to heat the substrate to a predetermined temperature;
• and
• a controller comprising program instructions for:
• positioning the substrate on the layer processing station, wherein the substrate includes the one or more through silicon vias filled with tungsten and an initial tungsten layer formed on a field region of the substrate and having an intrinsic residual stress that causes an interior portion of the substrate to deviate from a plane defined by edges of the substrate;
• exposing the field region of the substrate to an etchant;
• and
• removing a part of the initial tungsten layer to form an etched tungsten layer substantially covering the field region of the substrate and the one or more through silicon vias such that the through silicon vias remain filled, wherein the etched tungsten layer has an intrinsic residual stress that is less than the intrinsic residual stress of the initial tungsten layer such that the deviation of the substrate from the plane is reduced after forming the etched tungsten layer.