Method and apparatus for alignment optimization with respect to plurality of layers

1. A method of patterning a plurality of layers of a workpiece in a series of writing cycles in at least one write machine, the workpiece having N+2 (N>1) layers, and the N+2 layers having at least one boundary condition for pattern position locally and globally in relation to a reference, the method comprising:

a. Receiving a priori information regarding boundary conditions of layers 1 and N+2;

b. Calculating a deviation between a perfect fit between a pattern of layer 1 and a pattern of layer N+2 due to the boundary conditions;

c. Distributing the deviation between layers 2 to N+1 by assigning a selectable part of the deviation to each respective layer;

d. Writing a first layer according to the boundary condition of layer 1;

e. Aligning a subsequent pattern, which is currently being written, the aligning the subsequent pattern including calculating a transformation for fitting the subsequent pattern to the first layer;

f. Adding the assigned deviation for a subsequent layer to the calculated transformation to obtain an adjusted transformation;

g. Adjusting the subsequent pattern according to the adjusted transformation;

h. Verifying that said adjusted subsequent pattern is within alignment tolerances for the subsequent layer;

i. Writing said adjusted subsequent pattern on said first layer if said adjusted subsequent pattern is within the alignment tolerances for the subsequent layer;

j. Repeating e-i for the N+1 layers; and

k. Writing the N+2 layer according to the boundary condition of layer N+2.

2. The method of claim 1 , wherein a boundary condition for a layer among the N+2 layers covers at least part of the surface of the workpiece.

3. The method of claim 1 , wherein a boundary condition for a layer among the N+2 layers is set by an internal layer in the workpiece.

4. The method of claim 1 , wherein a boundary condition for a layer among the N+2 layers covers at least part of the surface of the workpiece and is set by an internal layer in the workpiece.

5. The method of claim 1 , wherein a boundary condition for a layer among the N+2 layers is at least one of:

local or global;

a compensation for an individual die;

for a subarea within a die;

for an individual zone on the workpiece; and

for the whole workpiece.

6. The method of claim 1 , wherein N layers are to be patterned, N being an integer greater than 1.

7. The method of claim 1 , wherein the calculating the transformation is performed in an alignment procedure.

8. The method of claim 1 , wherein the distribution of the deviation is based on at least one of:

distribution rules; and

an analysis of a level of requirements for alignment accuracy.

9. The method of claim 1 , wherein the selectable part of the deviation is selected as:

a difference in deviation divided by the number of subsequent layers; or

the whole difference in deviation if a high level of accuracy in alignment is required.

10. The method of claim 1 , wherein a boundary condition for a layer among the N+2 layers is that:

a different write machine will write the subsequent layer; or

the subsequent layer is a layer for which only a specific type of transformation is usable.

11. The method of claim 1 , wherein:

at least one layer of the workpiece has a plurality of dies distributed thereon;

each die is associated with an original circuit pattern and represented by original circuit pattern data; and

each die is associated with measurement data of alignment features of a respective layer.

12. The method of claim 1 , wherein a boundary condition for a layer among the N+2 layers is given by embedded dies.

13. The method of claim 1 , wherein first and second sets of boundary conditions are given when first and second workpieces are to be joined with a third workpiece.

14. The method of claim 1 , wherein optimization by distribution of the deviation is performed in response to detecting that the deviation is outside alignment tolerances for a layer among the N+2 layers.

15. The method of claim 1 , wherein the compensation in the adjusted subsequent pattern is at least one of:

local or global;

a compensation for an individual die;

for a subarea within a die;

for an individual zone on the workpiece; and

for the whole workpiece.

16. The method of claim 10 , wherein the different write machine is a via machine, and the subsequent layer is a solder layer.