Undercut control in isotropic wet etch processes

A method for manufacturing a semiconductor device, comprising:

• forming a first stacked transistor device in a first region corresponding to a first type, wherein the first stacked transistor device comprises a first plurality of work function metal layers;
• forming a second stacked transistor device spaced apart from the first stacked transistor device in a second region corresponding to a second type, wherein the second stacked transistor device comprises a second plurality of work function metal layers, and wherein a work function metal layer extends from the first and second plurality of work function metal layers to a space between the first and second stacked transistor devices;
• depositing a mask layer to cover the second stacked transistor device and portions adjacent the second stacked transistor device in the second region;
• removing part of the work function metal layer from the space between the first and second stacked transistor devices;
• replacing the removed part of the work function metal layer with a polymer brush layer;
• and
• selectively removing the first plurality of work function metal layers with respect to the polymer brush layer from the first region.

A method for manufacturing a semiconductor device, comprising:

• forming a first plurality of stacked channel portions in a first region corresponding to a first type, wherein the first plurality of stacked channel portions are alternatingly stacked with a first plurality of work function metal layers;
• forming a second plurality of stacked channel portions spaced apart from the first plurality of stacked channel portions in a second region corresponding to a second type, wherein the second plurality of stacked channel portions are alternatingly stacked with a second plurality of work function metal layers, and a work function metal layer extends from the first and second plurality of work function metal layers to a space between the first and second plurality of stacked channel portions;
• forming an organic planarization layer in the second region covering the second plurality of stacked channel portions and covering a first part of the work function metal layer in the space between the first and second plurality of stacked channel portions;
• removing a second part of the work function metal layer not covered by the organic planarization layer from the space between the first and second plurality of stacked channel portions;
• removing a portion of the first part of the work function metal layer under the organic planarization layer;
• replacing removed areas of the work function metal layer with a polymer brush layer;
• and
• selectively removing the first plurality of work function metal layers with respect to the polymer brush layer from the first region.