Patent ID: 11899376
Assignee: APPLIED MATERIALS, INC.
Field: Optics (Instruments)
Classification: CPC G  H | IPC G

Claim 9:
10. A method for forming alignment marks, comprising:
forming a first alignment mark on a first substrate, wherein the first alignment mark has a first width within 5% of a first critical dimension (CD) of copper pads on the first substrate;
forming a first dummy pattern of first dummy copper pads on the first substrate around the first alignment mark, wherein the first dummy pattern has a first dummy pattern density within 5% of a first copper pad density of the first substrate and the first dummy copper pads have a first dummy copper pad CD within 5% of the first CD of copper pads on the first substrate;
forming a second alignment mark on a second substrate, wherein the second alignment mark has a second width within 5% of a second critical dimension (CD) of copper pads on the second substrate; and
forming a second dummy pattern of second dummy copper pads on the second substrate around the second alignment mark, wherein the second dummy pattern has a second dummy pattern density within 5% of a second copper pad density of the second substrate and the second dummy copper pads have a second dummy copper pad CD within 5% of the second CD of copper pads on the second substrate,
wherein the first CD of copper pads on the first substrate is different than the second CD of copper pads on the second substrate,
wherein the second alignment mark nests within the first alignment mark from a top-down view point without any boundary overlay when the second substrate overlays or underlays the first substrate resulting in a predetermined alignment of the first substrate and the second substrate, and
wherein the second alignment mark when positioned within the first alignment mark from a top-down viewpoint is spaced away from the first alignment mark by approximately 5 microns to approximately 10 microns to allow for alignment shift.