Active pad patterns for gate alignment marks
View Patent ↗Methods for forming RX pads having gate alignment marks configured to enable noise reduction between layers while resulting in little or no non-uniformity of CMP processes for the IC, and the resulting devices, are disclosed. Embodiments include: providing, on a substrate, a RX pad having a SPM with a SPM horizontal and vertical positions at horizontal and vertical midpoints, respectively, of the first RX pad; providing a second RX pad abutting the first RX pad and a first STI pad abutting the second RX pad, each having a vertical midpoint at the SPM vertical position; forming a first gate alignment mark on the second RX pad and having vertical endpoints horizontally aligned with vertical endpoints of the second RX pad; and forming a second gate alignment mark on the first STI pad and having vertical endpoints horizontally aligned with vertical endpoints of the first STI pad.
1. A method comprising:
providing, on a substrate, a first active (RX) pad having a scribe line primary mark (SPM) with a SPM horizontal position at horizontal midpoint of the first RX pad and a SPM vertical position at a vertical midpoint of the first RX pad;
providing a second RX pad abutting the first RX pad having a vertical midpoint at the SPM vertical position;
providing a first shallow trench isolation (STI) pad abutting the second RX pad and having a vertical midpoint at the SPM vertical position;
forming a first gate alignment mark on the second RX pad and having vertical endpoints horizontally aligned with vertical endpoints of the second RX pad; and
forming a second gate alignment mark on the first STI pad and having vertical endpoints horizontally aligned with vertical endpoints of the first STI pad.
2. The method according to claim 1 , further comprising:
providing the first STI pad and the second RX pad with equal horizontal pitches.
3. The method according to claim 1 , comprising:
forming, on the second RX pad, a first set of gate alignment marks comprising the first gate alignment mark and a gate alignment mark on each side of the first gate alignment mark having a vertical length and vertical midpoint equal to the first gate alignment mark, the first set of gate alignment marks having a gate alignment mark set horizontal pitch;
forming, on the first STI pad, a second set of gate alignment marks comprising the second gate alignment mark and a gate alignment mark on each side of the second gate alignment mark having a vertical length and vertical midpoint equal to the second gate alignment mark, the second gate alignment mark set having the gate alignment mark set horizontal pitch; and
providing the first STI pad and the second RX pad with horizontal pitches according to the gate alignment mark set horizontal pitch.
4. The method according to claim 3 , further comprising:
providing the first RX pad with a horizontal pitch according to the gate alignment mark set horizontal pitch.
5. The method according to claim 4 , further comprising:
providing the first STI pad and the second RX pad with horizontal pitches of twice the gate alignment mark set horizontal pitch; and
providing the first RX pad with a horizontal pitch of four times the gate alignment mark set horizontal pitch.
6. The method according to claim 5 , further comprising:
providing a third RX pad abutting the first RX pad having a vertical midpoint at the SPM vertical position, the third RX pad having a horizontal pitch of twice the gate alignment mark set horizontal pitch; and
providing a second STI pad abutting the third RX pad and having a vertical midpoint at the SPM vertical position, the second STI pad having a horizontal pitch of twice the gate alignment mark set horizontal pitch.
7. A method comprising:
providing on a substrate first and second active (RX) pads each extending in a horizontal direction;
providing on the substrate a first shallow trench isolation (STI) pad extending in the horizontal direction, separating the first and second RX pads;
providing a scribe line primary mark (SPM) centered horizontally and vertically on the first RX pad; and
forming a plurality of gate alignment marks on the first and second RX pads and the first STI pad, each of the gate alignment marks extending in a vertical direction, and each having an endpoint on a horizontal edge of the second RX pad.
8. The method according to claim 7 , comprising:
providing on the substrate a third RX pad extending in the horizontal direction; and
providing on the substrate a second STI pad extending in the horizontal direction, the second STI pad separating the first and third RX pads, the gate alignment marks each having a second endpoint on a horizontal edge of the third RX pad.
9. The method according to claim 8 , wherein the gate alignment marks include a plurality of sets of gate alignment marks, each of the sets of gate alignment marks having a first gate alignment mark positioned at a horizontal midpoint of a set of gate alignment marks with gate alignment marks positioned on each side of the first gate alignment mark, the method further comprising:
forming a first set of gate alignment marks separated by a first distance from the SPM along the horizontal direction;
forming a second set of gate alignment marks separated by a second distance from the first set of gate alignment marks along the horizontal direction; and
forming a third set of gate alignment marks separated by the second distance from the second set of gate alignment marks along the horizontal direction.
10. The method according to claim 9 , comprising:
forming a fourth set of gate alignment marks being separated by the first distance from the SPM along the horizontal direction;
forming a fifth set of gate alignment marks separated by the second distance from the fourth set of gate alignment marks along the horizontal direction; and
forming a sixth set of gate alignment marks separated by the second distance from the fifth set of gate alignment marks along the horizontal direction.