Method of manufacturing a semiconductor device and a semiconductor device

A method of manufacturing a semiconductor device, comprising:

• forming a fin structure;
• forming an isolation insulating layer so that an upper portion of the fin structure is exposed from the isolation insulating layer;
• forming a sacrificial layer over at least sidewalls of the exposed upper portion of the fin structure;
• forming a first dielectric layer over the sacrificial layer;
• forming a second dielectric layer made of a different material than the first dielectric layer over the first dielectric layer;
• recessing the second dielectric layer;
• forming a third dielectric layer made of a different material than the second dielectric layer over the recessed second dielectric layer;
• partially removing the third dielectric layer to form a trench;
• and
• forming a fourth dielectric layer by filling the trench with a dielectric material different from the third dielectric layer, thereby forming a wall fin structure.

A method of manufacturing a semiconductor device, comprising:

• forming fin structures each including a stacked layer of first semiconductor layers and second semiconductor layers disposed over a bottom fin structure and a hard mask layer over the stacked layer;
• forming an isolation insulating layer so that the hard mask layer and the stacked layer are exposed from the isolation insulating layer;
• forming a sacrificial cladding layer over at least sidewalls of the exposed hard mask layer and stacked layer;
• forming a first dielectric layer over the sacrificial cladding layer, the first dielectric layer not fully filling a space between the fin structures;
• forming a second dielectric layer made of a different material than the first dielectric layer over the first dielectric layer to fully fill the space between the fin structures;
• recessing the second dielectric layer;
• forming a third dielectric layer made of a different material than the second dielectric layer over the recessed second dielectric layer;
• partially removing the third dielectric layer to form a trench;
• forming a fourth dielectric layer by filling the trench with a dielectric material different from the third dielectric layer, thereby forming a wall fin structure;
• removing the hard mask layer;
• forming a sacrificial gate structure;
• forming sidewall spacers on sidewalls of the sacrificial gate structure and sidewalls of a part of the wall fin structure;
• forming a source/drain structure adjacent opposing sides of the sidewall spacers;
• forming a fifth dielectric layer;
• removing the sacrificial gate structure;
• removing the sacrificial cladding layer;
• removing the first semiconductor layers;
• and
• forming a metal gate structure around the second semiconductor layers.