Satellite images help in studying various phenomena related to earth's surface. The range of applications varies from
agriculture, geology, coast and marine studies to urban development and environmental affairs. CubeSat projects belong
to the category of small satellites named Pico Satellites. They have a relative superiority over higher order satellites such
as Micro and Mini satellites in terms of their short development time, lower complexity, and most importantly less cost.
We present here an overview on the ongoing project EgyCubeSat-1, a Pico satellite that has a camera as an optical
payload with ground sample distance better than 100 meters, synchronous orbit, and low earth orbit in the range 600 ~
700 Km. The key innovation is the development of costumed optics that fit in the compact allocated space and result in
The continuous reduction of device dimensions and densities of integrated circuits increases the demand for accurate
process window models used in optical proximity correction. Beamfocus and dose are process parameters that have
significant contribution to the overall critical feature dimension error budget. The increased number of process
conditions adds to the model calibration time since a new optical model needs to be generated for each focus condition.
This study shows how several techniques can reduce the calibration time by appropriate selection of process conditions
and features while maintaining good accuracy. Experimental data is used to calibrate models using a reduced set of data.
The resulting model is compared with the model calibrated using the full set of data. The results show that using a
reduced set of process conditions and using process sensitive features can yield a model as accurate as the model
calibrated using the full set but in a shorter amount of time.
As technology advances to 45 nm node and below, the induced effects of etch process have an increasing contribution to
the device critical dimension error budget. Traditionally, original design target shapes are drawn based on the etch target.
During mask correction, etch modeling is essential to predict the new resist target that will print on the wafer. This step
is known as "Model Based Retargeting" (MBR). During the initial phase of process characterization, the sub-resolution
assist features (SRAF) are optimized whether based on the original design target shapes or based on a biased version of
the design target (resist target). The goal of the work is to study the different possibilities of SRAF placement to
maximize the accuracy and process window immunity of the final resist contour image. We will, statistically, analyze
and compare process window simulation results due to various SRAFs placements by changing the reference layer used
As patterning technology advances beyond 45-nm half-pitch, the process window shrinks dramatically even with
advanced resolution enhancement techniques. Beamfocus represents one of the process parameters that has a significant
contribution to the overall critical feature dimension error budget. In building an optical model for proximity correction,
the final model quality strongly depends on matching the focus used in the simulation to the experimental focus
conditions. In this paper, we present a new method to determine the best beamfocus and verify its accuracy using actual
test pattern measurements.
In optical lithography light diffracted from the mask has been customary assumed to have constant amplitude with the
angle of incidence of the light illuminating the mask. This approximation, known as constant scattering coefficient
approximation, has been successfully used at small NA. As the NA increases to unity and beyond, to cope with the
continuous demand for shrinking integrated circuits device dimensions and densities, the validity of this approximation
becomes questionable. In this paper, we study diffracted field variation with the angle of incidence using physical theory
of diffraction. An asymptotic theory like the physical theory of diffraction allows us to better understand, quantify, and
model using analytical formulae, induced effects of light diffraction from mask at oblique incidence. This paper presents
a semi analytical model that describes diffracted field variation with angle of incidence. The model accuracy is validated
by comparison with rigorous field simulations using Panoramic software.
Achieving faster Turn-Around-Time (TAT) is one of the most attractive objectives for the silicon wafer
manufacturers despite the technology node they are processing. This is valid for all the active technology
nodes from 130nm till the cutting edge technologies. There have been several approaches adopted to cut
down the OPC simulation runtime without sacrificing the OPC output quality, among them is using
stronger CPU power and Hardware acceleration which is a good usage for the advancing powerful
processing technology. Another favorable approach for cutting down the runtime is to look deeper inside
the used OPC algorithm and the implemented OPC recipe. The OPC algorithm includes the convergence
iterations and simulation sites distribution, and the OPC recipe is in definition how to smartly tune the OPC
knobs to efficiently use the implemented algorithm. Many previous works were exposed to monitoring the
OPC convergence through iterations and analyze the size of the shift per iteration, similarly several works
tried to calculate the amount of simulation capacity needed for all these iterations and how to optimize it
for less amount.
The scope of the work presented here is an attempt to decrease the number of optical simulations by
reducing the number of control points per site and without affecting OPC accuracy. The concept is proved
by many simulation results and analysis. Implementing this flow illustrated the achievable simulation
runtime reduction which is reflected in faster TAT. For its application, it is not just runtime optimization,
additionally it puts some more intelligence in the sparse OPC engine by eliminating the headache of
specifying the optimum simulation site length.
Immersion lithography is extending the lifetime of optical lithography by enabling numerical aperture (NA) greater than
unity. Along with scanner hardware improvements, modeling of hyper-NA lithography systems for optical proximity
correction (OPC) is also continuing to be necessary in improving photolithography capability. With the use of hyper-NA
immersion lithography and polarized illumination, the assumption of scalar optical pupil in optical system modeling may
no longer be valid. To fully describe the transmission of any polarization state through the optical system, Jones matrix is
necessary. It has been shown that Jones matrix can be described as a combination of apodization loss, birefringence,
diattenuation, scalar phase aberrations, and rotation effects. In this work, the impact of such effects on calibration and
accuracy of OPC models is characterized in terms of the model fit quality, model predictability, and changes to OPC
Sub-resolution assist features (SRAFs) or scatter bars (SBs) have steadily proliferated through IC
manufacturer data preparation flows as k1 is pushed lower with each technology node. The use of this
technology is quite common for gate layer at 130 nm and below, with increasingly complex geometric rules
being utilized to govern the placement of SBs in proximity to target layer features. Recently, model based
approaches for placement of SBs has arisen. In this work, the variety of rule-based and model-based SB
options are explored for the gate layer by using new characterization and optimization functions available
in the latest generation of correction and OPC verification tools. These include the ability to quantify
across chip CD control with statistics on a per gate basis. The analysis includes the effects of defocus,
exposure, and misalignment, and it is shown that significant improvements to CD control through the full
manufacturing variability window can be realized.