Detecting method for forming semiconductor device
In one embodiment, a method for detecting design defects is provided. The method includes receiving design data of an integrated circuit (IC) on a wafer, measuring wafer topography across the wafer to obtain topography data, calculating a scanner moving average from the topography data and the design data to provide a scanner defocus map across the wafer, and determining a hotspot design defect from the scanner defocus map. A computer readable storage medium, and a system for detecting design defects are also provided.
1. A method of detecting design defects, the method comprising:
receiving design data of an integrated circuit (IC) on a wafer;
measuring wafer topography across the wafer to obtain topography data;
calculating a scanner moving average from the topography data and the design data to provide a scanner defocus map across the wafer; and
determining a hotspot design defect from the scanner defocus map.
2. The method of claim 1 , wherein calculating the scanner moving average includes integrating scanner focus residuals along x and y directions across a wafer plane.
3. The method of claim 1 , wherein calculating the scanner moving average follows the equation:
M
A
(
x
,
y
)
=
1
s
∫
-
s
/
2
s
/
2
{
w
(
x
,
y
)
-
[
z
(
x
,
y
+
v
)
-
vR
x
(
x
,
y
+
v
)
-
xR
y
(
x
,
y
+
v
)
]
}
ⅆ
v
wherein x denotes the x-axis coordinate of the wafer plane,
y denotes the y-axis coordinate of the wafer plane,
z denotes an average wafer local height under a slit after least square (LSQ) plane fitting.
Rx denotes a scanner least square plane fit rotation angle about the x-axis within a slit,
Ry denotes a scanner least square plane fit rotation angle about the y-axis within a slit,
s denotes slit length along y axis,
w denotes wafer topography (z-height) measured by level sensor, and
v denotes a dummy variable of integration along slit in y direction.
4. The method of claim 1 , wherein determining the hotspot design defect includes detecting a hotspot defect pattern in the scanner defocus map.
5. The method of claim 4 , wherein the hotspot defect pattern is from a library of hotspot defect patterns.
6. The method of claim 1 , wherein determining the hotspot design defect is performed prior to photolithography processing.
7. The method of claim 1 , further comprising:
filtering the hotspot design defect from the design data.
8. A computer readable storage medium comprising computer readable instructions which when executed by a computer cause the computer to perform the operations of:
receiving design data of an integrated circuit (IC) on a wafer;
measuring wafer topography across the wafer to obtain topography data;
calculating a scanner moving average from the topography data and the design data to provide a scanner defocus map across the wafer; and
determining a hotspot design defect from the scanner defocus map.
9. The computer readable storage medium of claim 8 , wherein calculating the scanner moving average includes integrating scanner focus residuals along x and y directions across a wafer plane.
10. The computer readable storage medium of claim 8 , wherein calculating the scanner moving average follows the equation:
M
A
(
x
,
y
)
=
1
s
∫
-
s
/
2
s
/
2
{
w
(
x
,
y
)
-
[
z
(
x
,
y
+
v
)
-
vR
x
(
x
,
y
+
v
)
-
xR
y
(
x
,
y
+
v
)
]
}
ⅆ
v
wherein x denotes the x-axis coordinate of the wafer plane,
y denotes the y-axis coordinate of the wafer plane,
z denotes an average wafer local height under a slit after least square (LSQ) plane fitting.
Rx denotes a scanner least square plane fit rotation angle about the x-axis within a slit,
Ry denotes a scanner least square plane fit rotation angle about the y-axis within a slit,
s denotes slit length along y axis,
w denotes wafer topography (z-height) measured by level sensor, and
v denotes a dummy variable of integration along slit in y direction.
11. The computer readable storage medium of claim 8 , wherein determining the hotspot design defect includes detecting a hotspot defect pattern in the scanner defocus map.
12. The computer readable storage medium of claim 11 , wherein the hotspot defect pattern is searched from a library of hotspot defect patterns.
13. The computer readable storage medium of claim 8 , wherein determining the hotspot design defect is performed prior to photolithography processing.
14. The computer readable storage medium of claim 8 , further comprising computer readable instructions which when executed by a computer cause the computer to perform the operation of either filtering the hotspot design defect from the design data or compensating for the hotspot design defect by adjusting a scanner depth of focus.
15. A system for detecting design defects, the system comprising:
an inspection tool configured to measure wafer topography across a wafer to obtain topography data; and
a processor operably coupled to the inspection tool, the processor configured to perform the operations of:
receiving design data of the IC on the wafer;
calculating a scanner moving average from the topography data and the design data to provide a scanner defocus map across the wafer; and
determining a hotspot design defect from the scanner defocus map.
16. The system of claim 15 , wherein the processor is configured to calculate the scanner moving average by integrating scanner focus residuals along x and y directions across a wafer plane.
17. The system of claim 15 , wherein the processor is configured to calculate the scanner moving average following the equation:
M
A
(
x
,
y
)
=
1
s
∫
-
s
/
2
s
/
2
{
w
(
x
,
y
)
-
[
z
(
x
,
y
+
v
)
-
vR
x
(
x
,
y
+
v
)
-
xR
y
(
x
,
y
+
v
)
]
}
ⅆ
v
wherein x denotes a function of an x-axis of the wafer plane,
y denotes a function of a y-axis of the wafer plane,
z denotes a function of a z-axis perpendicular to the wafer plane,
Rx denotes a scanner focus residual along the x-axis,
Ry denotes a scanner focus residual along the y-axis,
s denotes slit length along y-axis,
w denotes wafer topography (z-height) measured by level sensor, and
v denotes a dummy variable of integration along slit in y direction.
18. The system of claim 15 , wherein the processor is configured to determine the hotspot design defect prior to photolithography processing by detecting a hotspot defect pattern in the scanner defocus map, the hotspot defect pattern stored in a library of hotspot defect patterns.
19. The system of claim 15 , wherein the processor is further configured to perform the operation of either filtering the hotspot design defect from the design data or compensating for the hotspot design defect by adjusting a scanner depth of focus.