Semiconductor device and method of manufacturing semiconductor device

A semiconductor device, comprising:

• a substrate;
• a first plurality of functional gate structures within a first circuit area over the substrate;
• a first plurality of dummy gate structures adjacent to the first circuit area over the substrate;
• a second plurality of functional gate structures within a second circuit area over the substrate;
• and
• a second plurality of dummy gate structures adjacent to the second circuit area over the substrate,
• wherein
• each dummy gate of the first plurality of dummy gate structures includes two first spacer portions, two first side portions sandwiched by the two first spacer portions, and a first core portion sandwiched by the two first side portions,
• each dummy gate of the second plurality of dummy gate structures includes two second spacer portions, two second side portions sandwiched by the two second spacer portions, and a second core portion sandwiched by the two second side portions, and
• a first ratio of a width of the first core portion to a summation of the width of the first core portion and widths of the first side portions is less than a second ratio of a width of the second core portion to a summation of the width of the second core portion and widths of the second side portions.

A method of manufacturing a semiconductor device, comprising:

• forming a first plurality of functional gate structures within a first circuit area over a substrate;
• forming a first plurality of dummy gate structures adjacent to the first circuit area over the substrate, a first average height being defined based on an average of distances from a lower surface of the substrate to upper surfaces of the first plurality of dummy gate structures along a height direction;
• forming a second plurality of functional gate structures within a second circuit area over the substrate;
• and
• forming a second plurality of dummy gate structures adjacent to the second circuit area over the substrate, a second average height being defined based on an average of distances from the lower surface of the substrate to upper surfaces of the second plurality of dummy gate structures along the height direction,
• wherein the first average height and the second average height are different.