Layout pattern of static random access memory having mirrored central regions and uniform peripheral contact pad arrangement

A layout pattern of a static random-access memory (SRAM), comprising:

• a substrate;
• four SRAM cell regions, which are arranged in a 2×2 array and form the layout pattern of the SRAM, wherein each of the SRAM cell regions defines a central region, a first peripheral region, and a second peripheral region, and wherein each of the SRAM cell regions comprises:
• a plurality of fin structures located on the substrate in the central region, and each fin structure extends along a second direction, wherein the second direction is Y direction in the X-Y coordinate;
• a plurality of gate structures located on the substrate in the central region, and each gate structure extends along a first direction and spans the plurality of fin structures to form a plurality of transistors, wherein the first direction is X direction in the X-Y coordinate, wherein the plurality of transistors comprise a first pull-up transistor (PU1), a first pull-down transistor (PD1), a second pull-up transistor (PU2), a second pull-down transistor (PD2), a first access transistor (PG1A), a second access transistor (PG1B), a third access transistor (PG2A) and a fourth access transistor (PG2B);
• a first word line contact pad located in the first peripheral region and connected to a gate of the first access transistor (PG1A) and a first word line;
• a second word line contact pad located in the first peripheral region and connected to a gate of the second access transistor (PG1B) and a second word line, wherein the first word line contact pad and the second word line contact pad do not overlap in the second direction;
• a third word line contact pad located in the second peripheral region and connected to a gate of the third access transistor (PG2A) and the first word line;
• and
• a fourth word line contact pad located in the second peripheral region and connected to a gate of the fourth access transistor (PG2B) and the second word line, wherein the third word line contact pad and the fourth word line contact pad do not overlap in the second direction;
• wherein the four SRAM cell regions include a first SRAM cell region and an adjacent second SRAM cell region, wherein a pattern of the central region of the first SRAM cell region is a mirror pattern with a pattern of the central region of the second SRAM cell region, and
• wherein, in each of the SRAM cell regions, a relative positional relationship between the first word line contact pad and the second word line contact pad in the first peripheral region is equal to a relative positional relationship between the third word line contact pad and the fourth word line contact pad in the second peripheral region.