Method of pattern placement correction
In one embodiment of the invention, a method for correcting a pattern placement on a substrate is disclosed. The method begins by detecting three reference points for a substrate. A plurality of sets of three die location points are detected, each set indicative of an orientation of a die structure, the plurality of sets include a first set associated with a first dies and a second set associated with a second die. A local transformation is calculated for the orientation of the first die and the second on the substrate. Three orientation points are selected from the plurality of sets of three die location points wherein the orientation points are not set members of the same die. A first global orientation of the substrate is calculated from the selected three points from the set of points and the first global transformation and the local transformation for the substrate are stored.
1. A system, comprising:
a processor; and
a memory, wherein the memory includes an application program configured to perform an operation for correcting a pattern placement on a substrate, the operation comprising:
detecting three reference points for a substrate;
detecting a plurality of sets of three die location points, each set indicative of an orientation of a die, the plurality of sets include a first set associated with a first die and a second set associated with a second die;
calculating a local transformation for an orientation of the first die and the second on the substrate;
selecting three orientation points from the plurality of sets of three die location points wherein the orientation points are not members of the same set;
calculating a first global orientation of the substrate from the selected three points from the set of points; and
storing the first global orientation and the local transformation for the substrate.
2. The system of claim 1 further comprising:
positioning the substrate in a lithography tool;
detecting the three reference points;
calculating a second global transformation from the three reference points;
combining the second global transformation with the local transformation to calculate an effective transformation of the substrate; and
applying the effective transformation as a correction to a digital mask during scanning.
3. The system of claim 2 further comprising:
correcting for the orientation of the die by applying the effective transformation to generate a per-die digital mask alignment correction; and
printing redistribution lithography layers on the die.
4. The system of claim 3 further comprising:
aligning the per-die digital mask with a model based pattern placement correction; and
correcting warpage of the substrate and orientation of the die.
5. The system of claim 1 , wherein calculating the first global orientation of the substrate comprises:
(a) measuring a value for an x/y rotation of the substrate,
(b) measuring a value for an expansion of the substrate;
(c) measuring a value for an orientation of the dies on the substrate; and
(d) calculating the global orientation from the values measured at (a), (b) and (c).
6. The system of claim 1 , wherein selecting three points from the set of points comprises:
selecting three alignment marks.