Granted Patent B2

US 12,631,977 · App. 17/608,750 · Granted May 19, 2026

Inventor: Maria Edo Hulsebos (Bergeijk, NL)

Assignee: ASML Netherlands B.V.

G03F9/7046G03F7/70633G03F7/70641G03F7/70683G03F9/7076

Abstract

Claims (182)

1 . A method for generating an alignment model associated with a mark layout of alignment marks disposed on a wafer, the mark layout including a relatively sparse mark layout and a relatively dense mark layout, the alignment model used by a lithographic apparatus for correcting wafer distortions during a patterning process of the wafer, the method comprising:

obtaining first measurement data associated with the relatively dense mark layout in comparison with the relatively sparse mark layout and second measurement data associated with the relatively sparse mark layout, wherein the first and second measurement data comprise at least one of alignment mark measurement position data or overlay measurement position data;

modeling a first fitted model that describes deformation of the wafer for the relatively dense mark layout, wherein the wafer deformation includes deformation of a surface of the wafer on which a desired pattern is transferred via the patterning process;

modeling a second fitted model that describes the wafer deformation for the relatively sparse mark layout; and

determining the alignment model, the determined alignment model being associated with the mark layout disposed on the wafer and based on cooperation between the first fitted model and the second fitted model via an oblique fitting technique, wherein the determining comprises:

determining a first output using the first fitted model and the first measurement data;

determining a second output using the oblique fitting technique, the second fitted model, the second measurement data, and the first fitted model; and

adjusting coefficients of the oblique fitting technique such that a difference between the first output of the first fitted model and the second output of the second fitted model is reduced, so that the second fitted model with the adjusted coefficients is the alignment model.

2 . The method according to claim 1 , wherein the oblique fitting technique is a generalized least squares fitting employing an oblique inner product matrix.

3 . The method of claim 2 , wherein the adjusting coefficients of the oblique inner product matrix comprises:

executing a mathematical model below:

x

c

=

M

y

⁢

c

w

c

w

=

(

M

x

T

⁢

W

T

⁢

WM

x

)

-

1

⁢

M

x

T

⁢

W

T

⁢

Wx

y

c

=

M

y

(

M

y

T

⁢

M

y

)

-

1

⁢

M

y

T

⁢

y

W

=

arg

⁢

min

W

⁢



y

c

-

x

c

(

W

)



wherein: W is the oblique inner product matrix; c w are fit coefficients of W associated with the second fitted model; M x comprises model functions of the second fitted model associated with the relatively sparse mark layout; M y comprises model functions of the first fitted model associated with the relatively dense mark layout; x c is the second output evaluated on the relatively dense mark layout based on M y associated with the first fitted model, the second measurement data x, and coefficients of W associated with the second fitted model; and y c is the first output based on the first fitted model and the first measurement data y.

4 . The method according to claim 1 , wherein the oblique fitting technique is an oblique projection least squares fitting employing an oblique projection matrix.

5 . The method of claim 4 , wherein the adjusting coefficients of the oblique projection matrix comprises:

executing a mathematical model below:

c

p

=

(

M

x

T

⁢

M

x

)

-

1

⁢

M

x

T

⁢

Px

P

=

arg

⁢

min

P

⁢

being

⁢

a

⁢

oblique

⁢

projection

⁢

matrix

⁢



y

c

-

M

y

⁢

c

p



y

c

=

M

y

(

M

y

T

⁢

M

y

)

-

1

⁢

M

y

T

⁢

y

wherein: P is the oblique projection matrix; c p are fit coefficients of the oblique projection matrix P associated with the second fitted model; M x comprises model functions associated with the relatively sparse mark layout; x is the second measurement data; M y comprises model functions of the first fitted model associated with the relatively dense mark layout; y c is the first output described by the first fitted model and evaluated on the first measurement data; and M y c p refers to the second output computed based on M x associated with the second fitted model, the second measurement data x, and evaluated on the relatively dense mark layout using M y associated with the first fitted model.

6 . The method of claim 4 , wherein the oblique fitting technique is configured to employ an oblique projection matrix.

7 . The method of claim 1 , wherein the second measurement data further comprises displacement data of the sparse mark layout with respect to predetermined nominal position data.

8 . The method of claim 1 , wherein the first and second fitted models are wafer fitted model.

9 . The method of claim 1 , wherein the second fitted model and/or the first model are a combination of two sub-models: a first sub-model comprising a first set of parameters, preferably four-parameters, and second sub-model comprising a second set of parameters, preferably six parameters.

10 . A computer program product comprising a non-transitory computer readable medium having instructions recorded thereon, the instructions when executed by a computer causes the computer to perform a method for generating an alignment model associated with a mark layout of alignment marks disposed on a wafer, the mark layout including a relatively sparse mark layout and a relatively dense mark layout, the alignment model used by a lithographic apparatus for correcting wafer distortions during a patterning process of the wafer, the method comprising:

obtaining first measurement data associated with the relatively dense mark layout in comparison with the relatively sparse mark layout and second measurement data associated with the relatively sparse mark layout, wherein the first and second measurement data comprise at least one of alignment mark measurement position data or overlay measurement position data;

modeling a first fitted model that describes deformation of the wafer for the relatively dense mark layout, wherein the wafer deformation includes deformation of a surface of the wafer on which a desired pattern is transferred via the patterning process;

modeling a second fitted model that describes the wafer deformation for the relatively sparse mark layout; and

determining the alignment model, the determined alignment model being associated with the mark layout disposed on the wafer and based on cooperation between the first fitted model and the second fitted model via an oblique fitting technique, wherein the determining comprises:

determining a first output using the first fitted model and the first measurement data;

determining a second output using the oblique fitting technique, the second fitted model, the second measurement data, and the first fitted model; and

adjusting coefficients of the oblique fitting technique such that a difference between the first output of the first fitted model and the second output of the second fitted model is reduced, so that the second fitted model with the adjusted coefficients is the alignment model.

11 . A measurement system comprising a computer program product comprising a non-transitory computer readable medium having instructions recorded thereon, the instructions when executed by a computer cause the computer to perform a method for generating an alignment model associated with a mark layout of alignment marks disposed on a wafer, the mark layout including a relatively sparse mark layout and a relatively dense mark layout, the alignment model used by a lithographic apparatus for correcting wafer distortions during a patterning process of the wafer, the method comprising:

obtaining first measurement data associated with the relatively dense mark layout in comparison with the relatively sparse mark layout and second measurement data associated with the relatively sparse mark layout, wherein the first and second measurement data comprise at least one of alignment mark measurement position data or overlay measurement position data;

modeling a first fitted model that describes deformation of the wafer for the relatively dense mark layout, wherein the wafer deformation includes deformation of a surface of the wafer on which a desired pattern is transferred via the patterning process;

modeling a second fitted model that describes the wafer deformation for the relatively sparse mark layout; and

determining the alignment model, the determined alignment model being associated with the mark layout disposed on the wafer and based on cooperation between the first fitted model and the second fitted model via an oblique fitting technique, wherein the determining comprises:

determining a first output using the first fitted model and the first measurement data;

determining a second output using the oblique fitting technique, the second fitted model, the second measurement data, and the first fitted model; and

adjusting coefficients of the oblique fitting technique such that a difference between the first output of the first fitted model and the second output of the second fitted model is reduced, so that the second fitted model with the adjusted coefficients is the alignment model.

12 . A lithography apparatus comprising a measurement system comprising a computer program product comprising a non-transitory computer readable medium having instructions recorded thereon, the instructions when executed by a computer cause the computer to perform a method for generating an alignment model associated with a mark layout of alignment marks disposed on a wafer, the mark layout including a relatively sparse mark layout and a relatively dense mark layout, the alignment model used by a lithographic apparatus for correcting wafer distortions during a patterning process of the wafer, the method comprising:

obtaining first measurement data associated with the relatively dense mark layout in comparison with the relatively sparse mark layout and second measurement data associated with the relatively sparse mark layout, wherein the first and second measurement data comprises at least one of alignment mark measurement position data and/or overlay measurement position data;

modeling a first fitted model that describes deformation of the wafer for the relatively dense mark layout, wherein the wafer deformation includes deformation of a surface of the wafer on which a desired pattern is transferred via the patterning process;

modeling a second fitted model that describes the wafer deformation for the relatively sparse mark layout; and

determining the alignment model, the determined alignment model being associated with the mark layout disposed on the wafer and based on cooperation between the first fitted model and the second fitted model via an oblique fitting technique, wherein the determining comprises:

determining a first output using the first fitted model and the first measurement data;

determining a second output using the oblique fitting technique, the second fitted model, the second measurement data, and the first fitted model; and

adjusting coefficients of the oblique fitting technique such that a difference between the first output of the first fitted model and the second output of the second fitted model is reduced, so that the second fitted model with the adjusted coefficients is the alignment model.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (26)