Integrated circuit with mixed row heights

An integrated circuit structure, comprising:

• a plurality of first cells each having a first cell height, wherein a first subset of the plurality of first cells are disposed along a first direction in a first cell row;
• and
• a plurality of second cells each having a second cell height different from the first cell height, wherein a second subset of the plurality of second cells are disposed along the first direction in a second cell row different from the first cell row,
• wherein the plurality of first cells each comprises a first plurality of active regions that each continuously extends across the first subset of the plurality of first cells, and wherein the plurality of second cells each comprises a second plurality of active regions that each continuously extends across the second subset of the plurality of second cells.

An integrated circuit designing system, comprising:

• a non-transitory storage medium encoded with a set of instructions;
• and
• a hardware processor communicatively coupled with the non-transitory storage medium and configured to execute the set of instructions, the set of instructions being configured to cause the processor to:
• provide a first library comprising a plurality of first cells that each comprises a first plurality of active regions continuously extending along a first direction;
• provide a second library comprising a plurality of second cells that each comprises a second plurality of active regions continuously extending along the first direction, wherein respective numbers of the first and second pluralities of active regions are different from each other;
• retrieve a first subset of the plurality of first cells from the first library and/or a second subset of the plurality of second cells from the second library;
• and
• place the first subset of the plurality of first cells extending along the first direction in a first plurality of cell rows and/or the second subset of the plurality of second cells extending along the first direction in a second plurality of cell rows.