Transcript Extreme Ultraviolet Lithographyx

Precision Engineering used in EUVL
By:
03/18/2003

Udayasri Jandhyala

Kanchan Joshi
ME250
Prof. Furman
Precision Engineering used in EUVL
By:
03/18/2003

Udayasri Jandhyala

Kanchan Joshi
ME250
Prof. Furman
Precision Engineering used in EUVL
• Lithography: A basic photographic process that allows more features to
be crammed onto a computer chip.
• EUVL: Lithography at extreme UV wavelengths is called EUVL.
• Lithography Process: Light is directed onto a mask-a sort of stencil of
an integrated circuit pattern and the image of that pattern is then
projected onto a semiconductor wafer covered with light sensitive
photoresist.
• Present: Current lithography techniques use deep ultraviolet range
248nm wavelengths to print 150 to 120nm size features.
• Future is EUVL: Creating smaller features requires wavelengths in the
Extreme Ultraviolet range. Light at Extreme Ultraviolet wavelengths is
absorbed instead of transmitted by lenses.
• Industry Developments: LLNL has developed multilayer coatings
capable of reflecting nearly 70% of EUV light at a wavelength of
13.4nm that can be used to fabricate structures with a smaller
minimum feature size 50nm.
03/18/2003
ME250
Prof. Furman
Precision Engineering used in EUVL
03/18/2003
ME250
Prof. Furman
Precision Engineering used in EUVL
•Micro Exposure tool (MET):
•A two-mirror camera which is
capable of printing 30nm features.
•Functional Requirements:
•Low distortion support of the
optics
•Precision adjustments for aligning
the optics
•Dimensional stability,both long
term-alignment and short termimage placement
03/18/2003
ME250
Prof. Furman
Precision Engineering used in EUVL
• The support ring provides upper and lower kinematic mounting
interfaces available to MET.
• The support ring has a 360 degrees rotational interface to the M2 cell
for the clocking adjustment and it provides attachment points for six
actuation flexures.
• The triangular shaped M1 cell attaches to the opposite ends of the
actuation flexures and together they provide high resolution adjustment
in 5 dof critical for optical alignment.
• Why Flexures:
– Strain attentuation
– The function of actuation flexure is to provide a single,adjustable
constraint along its axis. It is remotely actuated during alignment
process but otherwise functions as a passive constraint.
• The M1 and M2 cells each support three flexures that combine to
constrain 6dof for each optic.
• The support ring, actuation flexures etc are manufactured from Super
Invar (a low CTE alloy).
03/18/2003
ME250
Prof. Furman
Precision Engineering used in EUVL
•Actuation System: The actuation
flexures support and move the M1
cell relative to the support ring (often
called a Stewart platform).
•All six members are required to
provide rigid constraint and any pure
motion of the stage requires
coordinated motion of all six
flexures.
•A number of factors are considered
and balanced in the design of
actuation flexure.
•It must provide stiff axial constraint,
sufficient compliance and range of
motion in the non constraint
directions, low actuation force.
03/18/2003
ME250
Prof. Furman
Precision Engineering used in EUVL
Projection Optic Mount:
Objective:
Kinematic Constraint
Optic Cell
Bipod Flexure
Optic
03/18/2003
ME250
Prof. Furman
Precision Engineering used in EUVL
l
3DOF Blade Flexure:
z
w
x
y
Blade thk=t
l=10*t
w=l
Tx
Ty
Tz
Rx
Ry
Rz
S
S
S
F
F
F
Properties
03/18/2003
Material
Super Invar 32-5
CTE, linear 20 ºC
0.19 μm/m- ºC
CTE, linear 250 ºC
2.5 μm/m- ºC
ME250
Prof. Furman
Precision Engineering used in EUVL

4DOF Bipod Flexure:
Features:
• Blades in series to add compliances
• Equivalent to a sphere and a vee
• Connect-disconnect function
• Repeatable forces on optic
Tx
S
Ty
F
03/18/2003
Tz
S
Rx
F
Ry
F
z
Rz
F
ME250
x
y
Prof. Furman
Precision Engineering used in EUVL

The final assembly:
1.
2.
3.
Mechanical assembly
Precision
Accuracy
03/18/2003
ME250
Prof. Furman