Flexible merge scheme for source/drain epitaxy regions

A method comprising:

• forming first fin spacers on sidewalls of a first semiconductor fin and a second semiconductor fin, wherein the first and the second semiconductor fins have a first distance;
• etching the first semiconductor fin and the second semiconductor fin to form first recesses between the first fin spacers;
• forming second fin spacers on sidewalls of a third semiconductor fin and a fourth semiconductor fin, wherein the third and the fourth semiconductor fins have a second distance equal to or smaller than the first distance;
• etching the third semiconductor fin and the fourth semiconductor fin to form second recesses between the second fin spacers;
• and
• performing an epitaxy to simultaneously grow first epitaxy semiconductor regions from the first recesses and second epitaxy semiconductor regions from the second recesses, wherein the first epitaxy semiconductor regions are merged with each other, and the second epitaxy semiconductor regions are separated from each other.

A method comprising:

• in a common deposition process, forming a dielectric layer comprising a first portion on top surfaces and sidewalls of first semiconductor fins and a second portion on top surfaces and sidewalls of second semiconductor fins;
• in separate etching processes, etching the first portion of the dielectric layer and the second portion of the dielectric layer to form first fin spacers and second fin spacers, respectively, wherein the first fin spacers have a first height, and the second fin spacers have a second height greater than the first height;
• etching the first semiconductor fins to form first recesses between the first fin spacers;
• etching the second semiconductor fins to form second recesses between the second fin spacers;
• and
• in a common epitaxy process, growing first epitaxy semiconductor regions from the first recesses and second epitaxy semiconductor regions from the second recesses, wherein the first epitaxy semiconductor regions merge with each other, and the second epitaxy semiconductor regions are discrete from each other.