In an embodiment, a method (of manufacturing fins for a semiconductor device) includes: forming a first layer (on a semiconductor substrate) that has first spacers and etch stop layer (ESL) portions which are interspersed; forming second spacers on central regions of the first spacers and the ESL portions; removing exposed regions of the first spacers and the ESL portions and corresponding underlying portions of the semiconductor substrate; removing the second spacers resulting in corresponding first capped semiconductor fins and second capped semiconductor fins that are organized into first and second sets; each member of the first set having a first cap with a first etch sensitivity; and each member of the second set having a second cap with a different second etch sensitivity; and eliminating selected ones of the first capped semiconductor fins and selected ones of the second capped semiconductor fins.