Electrostatic discharge protection circuit with diode string

An integrated circuit comprising:

• a first-row first-type block and a first-row second-type block aligned along a first direction;
• a second-row second-type block and a second-row first-type block aligned along the first direction;
• a first diode formed between the first-row first-type block and the second-row second-type block, wherein the first-row first-type block and the second-row second-type block are aligned along a second direction which is perpendicular to the first direction;
• a second diode formed between the second-row first-type block and the first-row second-type block, wherein the second-row first-type block and the first-row second-type block are aligned along the second direction;
• a third-row second-type block and a third-row first-type block aligned along the first direction, wherein the third-row second-type block is adjacent to the second-row second-type block, and wherein the third-row first-type block is adjacent to the second-row first-type block;
• and
• a fourth-row first-type block and a fourth-row second-type block aligned along the first direction, wherein the fourth-row first-type block is adjacent to the third-row second-type block, and wherein the fourth-row second-type block is adjacent to the third-row first-type block.

A method of manufacturing an integrated circuit comprising:

• fabricating second-type wells in a first-type substrate;
• implanting first-type dopants into the second-type wells to generate a first first-type block in a first row, a second first-type block in a second row, and a third first-type block in the first row;
• implanting second-type dopants into the second-type wells to generate a first second-type block in the second row, a second second-type block in the first row, and a third second-type block in the second row;
• forming a first diode between the first first-type block and the first second-type block along a first column, forming a second diode between the second second-type block and the second first-type block along a second column, and forming a third diode between the third first-type block and the third second-type block along a third column;
• depositing a layer of metal above the second-type wells and the first-type substrate;
• and
• forming a first horizontal conductor connecting the second second-type block with the third first-type block and forming a second horizontal conductor connecting the first second-type block with the second first-type block.