Chamfered corner crackstop for an integrated circuit chip
View Patent ↗A corner crackstop is formed in each of the four corners of an integrated circuit (IC) chip, in which the corner crackstop differs structurally from a portion of the crackstop disposed along the sides of the IC chip. Each corner crackstop includes a plurality of layers, formed on a top surface of a silicon layer of the IC chip, within a perimeter boundary region that comprises a triangular area, in which a right angle is disposed on a bisector of the corner, equilateral sides of the triangle are parallel to sides of the IC chip, and the right angle is proximate to the corner relative to a hypotenuse of the triangle. The plurality of layers of the corner crackstop include crackstop elements, each comprising a metal cap centered over a via bar, in which the plurality of layers of the corner crackstop is chamfered to deflect crack ingress forces by each corner crackstop.
1. A corner crackstop comprising:
a plurality of n metallization layers formed on a silicon layer of an integrated circuit (IC) chip above a perimeter boundary region of a corner of said IC chip, said perimeter boundary region comprising a triangle, a right angle of said triangle being disposed proximately to said corner and sides of said triangle being parallel to sides of said IC chip; and
a number of crackstop elements disposed within each of said n metallization layers, each of said crackstop elements being longitudinally oriented in parallel to a hypotenuse of said triangle and being limited in length by said sides of said triangle,
a first crackstop element of a first metallization layer disposed most proximately to said right angle and having a smallest length, a second crackstop element of said first metallization layer adjoined distally to said first crackstop element and having a greater length, and an nth crackstop element of said first metallization layer adjoined distally to an (n−1)th crackstop element and having a greatest length,
a first crackstop element of a second metallization layer aligned vertically over said second crackstop element of said first metallization layer and having said greater length, and an (n−1)th crackstop element of said second metallization layer aligned vertically over said nth crackstop element of said first metallization layer and having said greatest length, and
a single crackstop element of an nth metallization layer aligned vertically over a second crackstop element of an (n−1)th metallization layer and having said greatest length.
2. The corner crackstop of claim 1 , each of said crackstop elements including a metal cap centered on a via bar.
3. The corner crackstop of claim 2 , a width of each of said crackstop elements being equal to a width of said metal cap, and a width of said via bar being less than said width of said metal cap.
4. The corner crackstop of claim 1 , said plurality of n metallization layers comprising corner crackstop elements that form a zigzag pattern on an outward-facing surface of said corner crackstop.
5. The corner crackstop of claim 2 , none of said metal caps and said via bars of any of said crackstop elements, formed in any of said n metallization layers within said perimeter boundary region contacting an electrical device in an active region of said IC chip.
6. The corner crackstop of claim 1 , said corner crackstop contacting a crackstop that differs in structure from said corner crackstop and parallels adjacent sides of said IC chip.
7. A corner crackstop comprising:
a plurality of n metallization layers formed on a silicon layer of an integrated circuit (IC) chip above a perimeter boundary region of a corner of said IC chip, said perimeter boundary region comprising a triangle, a right angle of said triangle being disposed proximately to said corner of said IC chip and sides of said triangle being parallel to sides of said IC chip; and
a number of crackstop elements disposed within each of said n metallization layers, each of said crackstop elements being longitudinally oriented in parallel to a hypotenuse of said triangle and being limited in length by said sides of said triangle,
a first number of crackstop elements of a first metallization layer equaling n, each of said first number of crackstop elements being disposed adjacent one to the other from a hypotenuse of said triangle toward said right angle,
a second number of crackstop elements of a second metallization layer equaling n−1, each of said second number of crackstop elements being aligned vertically above said first number of crackstop elements from said hypotenuse toward said right angle, and
a single crackstop element of an nth metallization layer aligned vertically above a crackstop element of an (n−1) metallization layer that is disposed adjacent to said hypotenuse of said triangle.
8. The corner crackstop of claim 7 , each of said crackstop elements including a metal cap centered on a via bar.
9. The corner crackstop of claim 8 , a width of each of said crackstop elements being equal to a width of said metal cap, and a width of said via bar being less than said width of said metal cap.
10. The corner crackstop of claim 7 , said plurality of n metallization layers comprising corner crackstop elements that form a zigzag pattern on an outward-facing surface of said corner crackstop.
11. The corner crackstop of claim 8 , none of said metal caps and said via bars of any of said crackstop elements, formed in any of said n metallization layers within said perimeter boundary region contacting an electrical device in an active region of said IC chip.
12. The corner crackstop of claim 7 , said corner crackstop contacting a crackstop that differs in structure from said corner crackstop and parallels adjacent sides of said IC chip.
13. A corner crackstop comprising:
a plurality of n metallization layers formed on a silicon layer of an integrated circuit (IC) chip above a perimeter boundary region of a corner of said IC chip, said perimeter boundary region comprising a triangle, a right angle of said triangle being disposed proximately to said corner and sides of said triangle being parallel to sides of said IC chip; and
a number of crackstop elements disposed within each of said n metallization layers, each of said crackstop elements being longitudinally oriented in parallel to a hypotenuse of said triangle and being limited in length by said sides of said triangle,
a first crackstop element of a first metallization layer disposed most proximately to said right angle and having a smallest length, a second crackstop element of said first metallization layer adjoined distally to said first crackstop element and having a greater length, and an nth crackstop element of said first metallization layer adjoined distally to an (n−1)th crackstop element and having a greatest length,
a first crackstop element of a second metallization layer aligned vertically over said second crackstop element of said first metallization layer and having said greater length, and an (n−1)th crackstop element of said second metallization layer aligned vertically over said nth crackstop element of said first metallization layer and having said greatest length,
a single crackstop element of an nth metallization layer aligned vertically over a second crackstop element of an (n−1)th metallization layer and having said greatest length, and
said corner crackstop contacting a crackstop that differs in structure from said corner crackstop and parallels adjacent sides of said IC chip.
14. The corner crackstop of claim 13 , each of said crackstop elements including a metal cap centered on a via bar.
15. The corner crackstop of claim 14 , a width of each of said crackstop elements being equal to a width of said metal cap, and a width of said via bar being less than said width of said metal cap.
16. The corner crackstop of claim 13 , said plurality of n metallization layers comprising corner crackstop elements that form a zigzag pattern on an outward-facing surface of said corner crackstop.
17. The corner crackstop of claim 14 , none of said metal caps and said via bars of any of said crackstop elements, formed in any of said n metallization layers within said perimeter boundary region contacting an electrical device in an active region of said IC chip.