Pattern measuring method, pattern measuring tool and computer readable medium
The present disclosure relates to a pattern measuring method to appropriately measure a height and a depth of a pattern having a high aspect ratio. The method includes measuring a width between a first pattern and another pattern formed on a wafer; calculating a value regarding an azimuth angle of a signal emitted from the wafer; and calculating height information from a portion between the first pattern and the other pattern to an upper portion of a pattern based on the measured width between the first pattern and the other pattern, the value regarding the azimuth angle, the value regarding an elevation angle, and relationship information thereof.
1. A pattern measuring method, comprising:
receiving a signal obtained by irradiating a wafer with a beam using a pattern measuring tool;
measuring a width between a first pattern and another pattern formed on the wafer and identifying a value corresponding to a signal amount between the first pattern and the other pattern, based on reception of the signal; and
calculating height information from a portion between the first pattern and the other pattern to an upper portion of the pattern based on the measured width between the first pattern and the other pattern and the value corresponding to the signal amount between the first pattern and the other pattern,
wherein the height information is calculated based on
H =L·sinθ/2tan ϕ
H: the height information
L: the width between the first pattern and the other pattern
θ: a value that changes according to a shape and a position of a detector
ϕ: the value corresponding to the signal amount between the first pattern and the other pattern.
2. The pattern measuring method according to claim 1 , wherein
the signal amount emitted from between the first pattern and the other pattern is measured based on the reception of the signal, and the height information is calculated based on a comparison between the measured signal amount and a reference signal amount.
3. The pattern measuring method according to claim 2 , wherein
a value ϕ corresponding to the signal amount between the first pattern and the other pattern is calculated based on
ϕ=b/a
a: the reference signal amount emitted from the upper portion of the pattern
b: the measured signal amount.
4. A pattern measuring tool that includes a beam irradiation subsystem, which irradiates a wafer with a beam and thus generates an output in response to a signal from the wafer, and a computer subsystem, wherein
the computer subsystem:
receives the signal obtained by irradiating the wafer with the beam using the pattern measuring tool;
measures a width between a first pattern and another pattern formed on the wafer and identifies a value corresponding to a signal amount between the first pattern and the other pattern, based on reception of the signal; and
calculates height information from a portion between the first pattern and the other pattern to an upper portion of the pattern based on the measured width between the first pattern and the other pattern and the value corresponding to the signal amount between the first pattern and the other pattern,
wherein the computer system calculates the height information based on
H =L·sinθ/2tanϕ
H: the height information
L: the width between the first pattern and the other pattern
θ: a value that changes according to a shape and a position of a detector
ϕ: the value corresponding to the signal amount between the first pattern and the other pattern.
5. The pattern measuring tool according to claim 4 , wherein
the computer system measures the signal amount emitted from between the first pattern and the other pattern based on the reception of the signal, and calculates the height information based on a comparison between the measured signal amount and a reference signal amount.
6. The pattern measuring tool according to claim 5 , wherein
the computer system calculates a value ϕ corresponding to the signal amount between the first pattern and the other pattern based on
ϕ=b/a
a: the reference signal amount emitted from the upper portion of the pattern
b: the measured signal amount.
7. The pattern measuring tool according to claim 4 , comprising: a storage medium that stores the 0, wherein the storage medium stores the 0 corresponding to a device condition of the beam irradiation subsystem.
8. The pattern measuring tool according to claim 4 , comprising: a storage medium that stores the 0, wherein the computer system measures a length of a shadow that starts from an edge of a pattern having a known height based on the signal obtained by irradiating the pattern having a known height with the beam.
9. The pattern measuring tool according to claim 8 , wherein the computer system calculates the θ based on
θ=tan-l(l/h)
l: the length of the shadow
h: the known height of the pattern.
10. The pattern measuring tool according to claim 4 , comprising: a storage medium that stores the 0, wherein the computer system measures a length of a shadow that starts from an edge of a pattern having a known inclination angle based on the signal obtained by irradiating the pattern having a known inclination angle with the beam.
11. The pattern measuring tool according to claim 10 , wherein the computer system calculates an elevation angle θ based on
θ=tan-l(d/l)
d: a depth of an end portion of the shadow of the pattern having a known inclination angle
l: the length of the shadow.
12. The pattern measuring tool according to claim 10 , wherein
the pattern having a known inclination angle is in a pyramid shape.
13. The pattern measuring tool according to claim 4 , wherein
the beam irradiation subsystem includes a stage to place the wafer, and a pattern having a known height or a known inclination angle is formed on the stage.
14. A non-transitory computer-readable medium that stores program instructions executable on a computer system of a pattern measuring tool so as to perform a method that is implemented by a computer that measures a pattern formed on a wafer, wherein
the method that is implemented by the computer includes:
receiving a signal obtained by irradiating the wafer with a beam using the pattern measuring tool;
measuring a width between a first pattern and another pattern formed on the wafer and identifying a value corresponding to a signal amount between the first pattern and the other pattern, based on reception of the signal; and
calculating height information from a portion between the first pattern and the other pattern to an upper portion of the pattern based on the measured width between the first pattern and the other pattern and the value corresponding to the signal amount between the first pattern and the other pattern,
wherein the height information is calculated based on
H =L·sinθ/2tanϕ
H: the height information
L: the width between the first pattern and the other pattern
θ: a value that changes according to a shape and a position of a detector
ϕ: the value corresponding to the signal amount between the first pattern and the other pattern.
15. The non-transitory computer-readable medium that stores program instructions according to claim 14 , wherein
the signal amount emitted from between the first pattern and the other pattern is measured based on the reception of the signal, and the height information is calculated based on a comparison between the measured signal amount and a reference signal amount.
16. The non-transitory computer-readable medium that stores program instructions according to claim 15 , wherein
a value ϕ corresponding to the signal amount between the first pattern and the other pattern is calculated based on
ϕ=b/a
a: the reference signal amount emitted from the upper portion of the pattern
b: the measured signal amount.