Overlay marks for reducing effect of bottom layer asymmetry

A semiconductor device, comprising:

• a combination overlay mark on a substrate, wherein the combination overlay mark comprises:
• a first area that comprises:
• an first upper layer that comprises a first plurality of upper gratings extending along a first direction and disposed at a pitch, and
• a first lower layer that comprises a first set of compound gratings extending along the first direction, the first set of compound gratings including a first plurality of lower gratings that are shifted from the first plurality of upper gratings by a distance along a second direction perpendicular to the first direction, and
• a second area comprises:
• a second upper layer that comprises a second plurality of upper gratings extending along the second direction and disposed at the pitch, and
• a second lower layer that comprises a second set of compound gratings extending along the second direction, the second set of compound gratings including a second plurality of lower gratings that are shifted from the second plurality of upper gratings by the distance along the first direction.

A combination overlay mark, comprising:

• a first region that includes a first area and a second area;
• and
• a second region that includes a third area and a fourth area,
• wherein the first area comprises:
• an first upper layer that comprises first symmetric upper gratings extending lengthwise along a first direction and disposed evenly at a pitch along a second direction perpendicular to the first direction, and
• a first lower layer that comprises first asymmetric lower gratings extending lengthwise along the first direction and being asymmetric along the second direction,
• wherein the second area comprises:
• a second upper layer that comprises second symmetric upper gratings extending lengthwise along the first direction and disposed evenly at the pitch along the second direction, and
• a second lower layer that comprises second asymmetric lower gratings extending lengthwise along the first direction and being asymmetric along the second direction,
• wherein the third area comprises:
• an third upper layer that comprises third symmetric upper gratings extending lengthwise along the second direction and disposed evenly at the pitch along the first direction, and
• a third lower layer that comprises third asymmetric lower gratings extending lengthwise along the second direction and being asymmetric along the first direction,
• wherein the fourth area comprises:
• a fourth upper layer that comprises fourth symmetric upper gratings extending lengthwise along the second direction and disposed evenly at the pitch along the first direction, and
• a fourth lower layer that comprises fourth asymmetric lower gratings extending lengthwise along the second direction and being asymmetric along the first direction.