微結構及運動平台精度檢測

1. Compensation sensor1
Micro-stylus probe
Compensation
sensor2
Spindle
Ring artifact
X-slide
X
Z
Y
Micro-aspheric specimen
Figure 1 A scanning micro-stylus instrument for micro-aspherics
Measuring systems for microstructures and precision stages
W. Gao
Department of Nanomechnics, Tohoku University
Aramaki Aza Aoba 6-6-01, Sendai 980-8579, Japan
gaowei@nano.mech.tohoku.ac.jp
This keynote speech presents a number of micro/nano-measuring systems for
microstructures and precision stages, which have been developed in Tohoku
University.
Measuring systems for microstructures
Figure 1 shows a scanning measurement system aspheric microlenses and microlens
moulds [1]. A contact-stylus sensor, which is mounted on an air-bearing linear slide,
is employed to spirally scan the surface of the aspheric microlens mounted on an
air-bearing spindle. To remove the influence of the scanning error motions of the
spindle and the slide, a ring artifact is attached around the lens and two
capacitance-type displacement sensors are set on the two sides of the contact-stylus
sensor to scan the surface of the ring artifact.. The micro-stylus is composed of a
glass shaft and a glass micro-ball. A PZT actuator is integrated into the glass tube
micro-ball stylus to construct a tapping mode micro-ball stylus.

2. Focusing lensesCollecting lens
LD
Y
X
Z
AFM scanner
Tool
alignment
table
AFM cantilever
PD
AFM
alignment
table
Cutting tool
Cutting Tool assembly
AFM assembly
Optical probe
assembly
B
Laser
beam
Figure 2: An automatic alignment AFM for cutting edge measurement
Air-spindle (-spindle)
Air-slide (X-stage)
Specimen
AFM probe unit
X
Z
Y
Figure 3: A spiral scanning-type AFM for large area microstructures
Figure 2 shows an atomic force microscope (AFM) based instrument for nanometer
edge profile measurement of diamond cutting tools [2, 3]. The instrument is
combined with an AFM unit and an optical sensor for alignment of the AFM probe
tip with the top of the diamond cutting tool edge in the submicrometer range. The tool
edge top is first brought to the center of the beam waist in the XZ-plane through
monitoring the variation of the photodiode output. The tool edge is pulled back after
recording the position of the tool edge top at the beam center. Then, the AFM tip is
similarly positioned to the beam center to aligned with the tool top.
Figure 3 presents a spiral scanning-type AFM for large area mico-textured surfaces.
The instrument consists of a compact and precision AFM probe-unit, a linear stage
and a spindle [4]. The sample is mounted on the spindle and the AFM probe-unit is

3. Sample
h(x)
Tip
Resonator
Applied
AC voltage
Output
current
+ + +
w (x)
R
xX
Z
Scanner
EFM Probe unit
P
F(x)
H2
H1
Figure 4: A electrostatic force microscope for noncontact surface profile
measurement of microstructures.
mounted on the linear stage. In this measurement system, the specimen is measured
rapidly in a spiral scanning pattern, which is made by rotating the spindle and moving
the linear stage in radial direction.
Figure 4 shows a scanning electrostatic force microscope proposed for noncontact
surface profile measurement [5]. A charged conducting probe tip is oscillated by a
tuning fork quartz crystal resonator. The probe tip is scanned over the sample surface
by using an XY scanner in such a way that the frequency shift of the tuning fork
oscillation, which corresponds to the electrostatic force gradient, is kept constant by
controlling the probe Z position with a Z scanner. A dual height method is proposed
to accurately obtain the tip to sample distances through removing the influence of the
electric field distribution on the sample surface.
Measuring systems for precision stages
Figure 5 shows a three-axis surface encoder which can measure the positions along
the primary moving axes (X, and Y-axes) and secondary moving axis (Z-axis) of a
precision linear stage simultaneously [6-9]. It is composed of a reflective-type scale
grating and an optical sensor head. A reference grating, which is identical to the scale
grating except the scale length, is employed in the optical sensor head. Positive and
negative first-order diffracted beams from the two gratings are superposed with each
other in the optical sensor head to generate interference signals. The surface encoder
has sub-nanometer resolutions in both the X-, Y- and Z-axes.

4. Prism
Prism
Prism
Collimating lens
LD
BS
PD X+1
PD X-1
Detector unit
Scale grating
Reference grating
Optical sensor head
UsX+1
UsX-1
UrX+1UrX-1


Aperture
 
Z
X
Y
Figure 5: A three-axis surface encoder for stage measurement
Incident beam
Reflected beam
LD unit
PBS+QWP
-1st-order
+1st-order
0th-order
Target
(Rectangular
grating )
Objective lenses
QPD 3
QPD 2
QPD 111
f
a
a
Y
Z
X
Z
XY
V H
Incident beam
Reflected beam
LD unit
PBS+QWP
-1st-order
+1st-order
0th-order
Target
(Rectangular
grating )
Objective lenses
QPD 3
QPD 2
QPD 111
f
a
a
Y
Z
X
Z
XY
V HV H
Figure 6: A three-axis angle sensor for stage measurement
Figure 6 shows the schematic of a three-axis angle sensor for angular error motion
measurement of a linear stage [10]. The sensor consists of a laser diode as the light
source, and quadrant photodiodes (QPDs) as the optical position-sensing device.
Differing from a conventional 2-axis autocollimator, the sensor uses a diffractive
grating as the target mirror. It is confirmed that the resolutions were about 0.01
arc-seconds in all the three axes.

5. References:
1) Wei Gao, "Precision Nanometrology: Sensors and Measuring Systems for
Nanomanufacturing", Springer，ISBN 978-1849962537, (2010).
2) Wei Gao, Takenori Motoki and Satoshi Kiyono, "Nanometer edge profile
measurement of diamond cutting tools by atomic force microscope with optical
alignment sensor", Precision Engineering, 30 (2006), 396-405.
3) W. Gao, T. Asai, Y. Arai, "Precision and fast measurement of 3D cutting edge
profiles of single point diamond micro-tools", CIRP Annals - Manufacturing
Technology, 58-1 (2009), 451-454.
4) Wei Gao, Jun Aoki, Bing-Feng Ju, Satoshi Kiyono, "Surface profile measurement
of a sinusoidal grid using an atomic force microscope on a diamond turning
machine", Precision Engineering, 31 (2007), 304-309.
5) Wei Gao, Shigeaki Goto, Keiichiro Hosobuchi, So Ito, Yuki Shimizu, "A
noncontact scanning electrostatic force microscope for surface profile measurement",
CIRP Annals - Manufacturing Technology, 61-1 (2012) 471–474.
6) W. Gao, A. Kimura, "A Three-axis Displacement Sensor with Nanometric
Resolution", CIRP Annals - Manufacturing Technology, 56-1 (2007), 529-532.
7) Akihide Kimura, Wei Gao, Yoshikazu Arai, Zeng Lijiang, "Design and
construction of a two-degree-of-freedom linear encoder for nanometric measurement
of stage position and straightness", Precision Engineering, 34 (2010), 145–155.
8) Akihide Kimura, Wei Gao, WooJae Kim, Koji Hosono, Yuki Shimizu, Lei Shi,
Lijiang Zeng, "A sub-nanometric three-axis surface encoder with short-period planar
gratings for stage motion measurement", Precision Engineering, 36 (2012), 576-585.
9) Wei Gao, Akihide Kimura, "A fast evaluation method for pitch deviation and
out-of-flatness of a planar scale grating", CIRP Annals - Manufacturing Technology,
59 (2010), 505-508..
10) W. Gao, Y. Saito, H. Muto, Y. Araia and Y. Shimizu, "A three-axis
autocollimator for detection of angular error motions of a precision stage", Annals of
the CIRP, 60-1 (2011), 2011, 515-518.