Patent ID: 6365924
Filing Date: 2002-04-02
Classification: H01L

Abstract:
An electrostatic discharge (ESD) protection structure comprising:corner cells, each corner cell comprising a first semiconductor region having a square-shape and being of a first conductivity type; said first semiconductor region being surrounded on two sides by a second semiconductor region of a second conductivity type, said first and said second semiconductor regions both formed in a second square-shaped semiconductor region of the first semiconductor conductivity type, said second square-shaped semiconductor region formed in a third square-shaped semiconductor region of the second conductivity type, said corner cells to form all corners of said ESD structure; edge cells, each edge cell comprising a first semiconductor region having a square-shape and being of the first conductivity type; said first semiconductor region being surrounded on three sides by a second semiconductor region of the second conductivity type, said first and said second semiconductor regions both formed in a second square-shaped semiconductor region of the first semiconductor conductivity type, said second square-shaped semiconductor region formed in a third square-shaped semiconductor region of the second semiconductor conductivity type, said edge cells to form all edges of said ESD structure; and center cells, each center cell comprising a first semiconductor region having a square-shaped semiconductor region and being of the first conductivity type; said first semiconductor region being surrounded on four sides by a second semiconductor region of the second conductivity type, said first and said second semiconductor regions both formed in a second square-shaped semiconductor region of the first conductivity type, said second square-shaped semiconductor region formed in a third square-shaped semiconductor region of the second conductivity type, said center cells to form all portions of said ESD structure which are not formed by said corner cells and said edge cells.