Positional deviation measuring device, non-transitory computer-readable recording medium containing a positional deviation measuring program, and method of manufacturing semiconductor device
View Patent ↗According to one embodiment, an adjusting unit adjusts a refracting angle of incident light with respect to a substrate, a detector detects reflected light from the substrate, and a calculating unit calculates positional deviation of the pattern based on patterns respectively reflected in reflected lights obtained from the incident light generating N number of refracting angles with respect to the substrate, where N is an integer of two or greater.
1. A positional deviation measuring device comprising:
an adjusting unit configured to adjust a refracting angle of incident light with respect to a substrate;
a detector configured to detect reflected lights from the substrate; and
a calculating unit configured to calculate positional deviation of a pattern based on patterns respectively reflected in the reflected lights obtained from incident light generating N number of refracting angles with respect to the substrate, where N is an integer of two or greater.
2. The positional deviation measuring device of claim 1 , wherein the adjusting unit is an inclination adjusting unit that inclines an optical axis with respect to the substrate.
3. The positional deviation measuring device of claim 1 , wherein the adjusting unit is a wavelength adjusting unit that adjusts the wavelength of the incident light.
4. The positional deviation measuring device of claim 1 , wherein when N number of actual measurements of positional deviation of the pattern corresponding to the N number of refracting angles are given, the calculating unit solves N number of simultaneous equations that hold for the N number of refracting angles and the N number of actual measurements of positional deviation, thereby calculating the positional deviation of the pattern.
5. The positional deviation measuring device of claim 4 , wherein the positional deviation is deviation in alignment of an upper-layer pattern and lower-layer pattern formed over the substrate, or a warp of the substrate.
6. The positional deviation measuring device of claim 5 , wherein letting Δθ 1 , Δθ 2 , . . . , Δθ N be displacement angles of an incident angle that induce the refracting angles, OL be the deviation in alignment, OL 1 , OL 2 , . . . , OL N be actual measurements of the positional deviation, θ 0 be a warp of the substrate, h be the distance between the upper-layer pattern and the lower-layer pattern, n 1 be the refractive index of a medium on the upper-layer pattern, and n 2 be the refractive index of a medium between the upper-layer pattern and the lower-layer pattern, the N number of simultaneous equations are given by:
OL
1
=
OL
+
h
·
tan
(
sin
-
1
(
n
1
/
n
2
·
sin
(
θ
0
+
Δ
θ
1
)
)
)
OL
2
=
OL
+
h
·
tan
(
sin
-
1
(
n
1
/
n
2
·
sin
(
θ
0
+
Δ
θ
2
)
)
)
…
OL
N
=
OL
+
h
·
tan
(
sin
-
1
(
n
1
/
n
2
·
sin
(
θ
0
+
Δ
θ
N
)
)
)
.