US 11,953,448 B2Granted

Method for defect inspection

AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.

InventorsTsun-Cheng Tang, Hao-Ming Chang, Sheng-Chang Hsu, Cheng-Ming Lin

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Abstract

A method for defect inspection includes receiving a substrate having a plurality of patterns; obtaining a gray scale image of the substrate, wherein the gray scale image includes a plurality of regions, and each of the regions has a gray scale value; comparing the gray scale value of each region to a gray scale references to define a first group, a second group and an Nth group, wherein each of the first group, the second group and the Nth group has at least a region; performing a calculation to obtain a score; and when the score is greater than a value, the substrate is determined to have an ESD defect, and when the score is less than the value, the substrate is determined to be free of the ESD defect.

Claims20

Dependent claims

A method for defect inspection, comprising:

receiving photomask having a surface and a plurality of patterns disposed on the surface;
obtaining a gray scale image of the photomask, using a scanner of a lithography system, wherein the gray scale image comprises a plurality of regions, and each of the regions has a gray scale value;
comparing the gray scale value of each region to a gray scale reference, using a computing system of the lithography system, to define a first group, a second group and an Nth group, wherein each of the first group, the second group and the Nth group has at least a region, and the region in the first group has a first difference between its gray scale value and the gray scale reference, the region in the second group has a second difference between its gray scale value and the gray scale reference, and the region in the Nth group has an Nth difference between its gray scale value and the gray scale reference;
performing a calculation according to the first difference, the second difference and the Nth difference to obtain a score in order to improve an inspection for an electrostatic discharge (ESD) defect by the computing system of the lithography system;
determining the photomask to have the ESD defect or to be free of the ESD defect according to the score obtained from the calculation, wherein the calculation is performed according to an equation (1):
Ws
=
∑
e
1
(
G
)
G
⁢
1
+
∑
e
2
(
G
)
G
⁢
2
+
∑
e
3
(
G
)
G
⁢
3
+
…
⁢
∑
e
n
(
G
)
G
⁢
n
∑
(
G
)
G
⁢
1
,
G
⁢
2
,
G3
,
…
⁢
Gn
(
1
)
wherein Ws is the score, G is an individual difference of a region in a first group G1, a second group G2, a third group G3 and a Nth group GN, and e1 is a first weighting factor, e2 is a second weighting factor, and en is an Nth weighting factor;
and
performing an exposure operation using the photomask when the photomask is determined to be free of the ESD defect, or removing the photomask from the exposure operation when the photomask is determined to have the ESD defect.

68 more elements

A method for defect inspection, comprising:

receiving a photomask having a surface and a plurality of patterns disposed on the surface;
obtaining a gray scale image of the photomask using a scanner of a lithography system;
defining a defect region in the gray scale image, using a computing system of the lithography system, wherein the defect region has a plurality of first regions, and each of the first regions has a gray scale value and a difference between the gray scale value and a gray scale reference;
performing a calculation to obtain a score in order to improve an inspection for a complicated defect by the computing system of the lithography system;
and
determining the photomask to have the complicated defect or to be free of the complicated defect according to the score obtained from the calculation, wherein the calculation is performed according to an equation (2):
W
s
=
Σ
⁢

(
G
×
e
1
)
G
⁢
⁢
1

+
Σ
⁢

(
G
×
e
2
)
G
⁢
⁢
2

+
Σ
⁢

(
G
×
e
3
)
G
⁢
⁢
3

+
…
Σ
⁢

G

G
⁢
⁢
1
,
G
⁢
⁢
2
,
G
⁢
⁢
3
⁢
…
(
2
)
wherein Ws is the score, G is an individual difference of a region in a first group G1, a second group G2, a third group G3 and an Nth group GN, e1 is a first weighting factor, e2 is a second weighting factor, and en is an Nth weighting factor;
and
performing an exposure operation using the photomask when the photomask is determined to be free of the complicated defect, or removing the photomask from the exposure operation when the photomask is determined to have the complicated defect.

79 more elements

A method for defect inspection, comprising:

receiving a photomask having a surface and a plurality of patterns disposed on the surface;
obtaining a gray scale image of the photomask using a scanner of a lithography system;
defining a defect region in the gray scale image, using a computing system of the lithography system, wherein the defect region has at least a first region and a plurality of second regions, the first region has a gray scale value and a difference between the gray scale value of the first region and a gray scale reference, and each second region has a gray scale value and a difference between the gray scale value of the second region and the gray scale reference;
performing a first calculation, using the computing system of the lithography system, according to the difference between the gray scale reference and the gray scale values of the first region and the second regions in the defect region to obtain a score;
performing a second calculation, using the computing system of the lithography system, to obtain a graphical diagram,
wherein the first calculation and the second calculating are performed to improve an inspection to a hard mask/shielding layer extension defect, when two peaks are shown in the graphical diagram, determining the photomask to have a shielding layer extension defect, and when more than two peaks are shown in the graphical diagram, determining the photomask to have the hard mask/shielding layer extension defect;
and
performing a first removal operation and a second removal operation when the photomask is determined to have the hard mask/shielding layer extension defect, and performing the second removal operation when the photomask is determined to have the shielding layer extension defect.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/842,678Filed 7 Apr 2020 · us provisional application
Priority: 27 Sep 2019
Published: US 2021/0096086 A11 Apr 2021
Granted: 9 Apr 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G01N 21/8851
Investigating the presence of flaws or contamination: scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment,…
G01N 21/9501
Characterised by the material or shape of the object to be examined: semiconductor wafers
G01N 21/956
Characterised by the material or shape of the object to be examined: inspecting patterns on the surface of objects
G06T 7/001
Industrial image inspection: using an image reference approach