U.S. patent application number 17/401750 was filed with the patent office on 2021-12-02 for single cell grey scatterometry overlay targets and their measurement using varying illumination parameter(s).
The applicant listed for this patent is KLA-TENCOR CORPORATION. Invention is credited to Eran Amit, Amnon Manassen, Yuri Paskover.
Application Number | 20210373445 17/401750 |
Document ID | / |
Family ID | 1000005771521 |
Filed Date | 2021-12-02 |
United States Patent
Application |
20210373445 |
Kind Code |
A1 |
Manassen; Amnon ; et
al. |
December 2, 2021 |
Single Cell Grey Scatterometry Overlay Targets and Their
Measurement Using Varying Illumination Parameter(s)
Abstract
Scatterometry overlay (SCOL) measurement methods, systems and
targets are provided to enable efficient SCOL metrology with in-die
targets. Methods comprise generating a signal matrix by:
illuminating a SCOL target at multiple values of at least one
illumination parameter, and at multiple spot locations on the
target, wherein the illumination is at a NA (numerical aperture)
>1/3 yielding a spot diameter <1.mu., measuring interference
signals of zeroth and first diffraction orders, and constructing
the signal matrix from the measured signals with respect to the
illumination parameters and the spot locations on the target; and
deriving a target overlay by analyzing the signal matrix. The SCOL
targets may be reduced to be a tenth in size with respect to prior
art targets, as less and smaller target cells are required, and be
easily set in-die to improve the accuracy and fidelity of the
metrology measurements.
Inventors: |
Manassen; Amnon; (Haifa,
IL) ; Paskover; Yuri; (Binyamina, IL) ; Amit;
Eran; (Haifa, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KLA-TENCOR CORPORATION |
Milpitas |
CA |
US |
|
|
Family ID: |
1000005771521 |
Appl. No.: |
17/401750 |
Filed: |
August 13, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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16491963 |
Sep 6, 2019 |
11119417 |
|
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PCT/US2019/045039 |
Aug 5, 2019 |
|
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17401750 |
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62770680 |
Nov 21, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01B 11/02 20130101;
G01B 9/0201 20130101; G03F 7/70633 20130101; G01B 11/272
20130101 |
International
Class: |
G03F 7/20 20060101
G03F007/20; G01B 9/02 20060101 G01B009/02; G01B 11/27 20060101
G01B011/27 |
Claims
1. A SCOL target comprising a single cell having periodic
structures at a plurality of layers and measuring 2 .mu.m by 2
.mu.m or smaller.
2. The SCOL target of claim 1, wherein the periodic structures are
at most four pitch bars wide.
3. The SCOL target of claim 2, wherein the periodic structures are
two pitch bars wide.
4. The SCOL target of claim 1, placed in-die on a corresponding
wafer.
5. The SCOL target of claim 1, wherein the periodic structures are
gratings.
6. The SCOL target of claim 5, further comprising at least one
intermediate layer between the plurality of layers.
7. The SCOL target of claim 1, wherein the single cell is
configured to be illuminated with a spot diameter less than 1
.mu.m.
8. The SCOL target of claim 7, wherein a numerical aperture for the
spot diameter is greater than 1/3.
9. The SCOL target of claim 1, wherein the single cell is
configured to be illuminated at multiple spot locations.
10. The SCOL target of claim 9, wherein the multiple spot locations
are within a pitch of at least one of the periodic structures.
11. The SCOL target of claim 1, wherein the periodic structures are
aligned.
12. The SCOL target of claim 1, wherein the periodic structures are
configured to provide zeroth and first order mixing.
13. The SCOL target of claim 1, wherein the periodic structures are
configured to provide overlap between the zeroth order and the
first order in measured signals from the periodic structures.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 16/491,963 filed Sep. 6, 2019, which is a national stage of
PCT/US2019/045039 filed Aug. 5, 2019, which claims priority to the
provisional patent application filed Nov. 21, 2008 and assigned
U.S. App. No. 62/770,680, the disclosures of which are hereby
incorporated by reference.
BACKGROUND OF THE INVENTION
1. Technical Field
[0002] The present invention relates to the field of semiconductor
metrology, and more particularly, to scatterometry overlay (SCOL)
targets and metrology modules and methods for measuring them.
2. Discussion of Related Art
[0003] Typical SCOL metrology utilizes multiple cells having
multiple periodic structures in corresponding layers, which are
displaced with respect to each other by predetermined offsets to
enable the derivation of the overlay from differential signals
between the cells.
SUMMARY OF THE INVENTION
[0004] The following is a simplified summary providing an initial
understanding of the invention. The summary does not necessarily
identify key elements nor limit the scope of the invention, but
merely serves as an introduction to the following description.
[0005] One aspect of the present invention provides scatterometry
overlay (SCOL) measurement method comprising: generating a signal
matrix by: illuminating a SCOL target at multiple values of at
least one illumination parameter, and at multiple spot locations on
the target, wherein the illumination is at a NA (numerical
aperture) >1/3 yielding a spot diameter <1.mu., measuring
interference signals of zeroth and first diffraction orders, and
constructing the signal matrix from the measured signals with
respect to the illumination parameters and the spot locations on
the target; and deriving a target overlay by analyzing the signal
matrix.
[0006] These, additional, and/or other aspects and/or advantages of
the present invention are set forth in the detailed description
which follows; possibly inferable from the detailed description;
and/or learnable by practice of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] For a better understanding of embodiments of the invention
and to show how the same may be carried into effect, reference will
now be made, purely by way of example, to the accompanying drawings
in which like numerals designate corresponding elements or sections
throughout.
[0008] In the accompanying drawings:
[0009] FIGS. 1A and 1B are high-level schematic illustrations of
SCOL targets and respective measurement systems, according to some
embodiments of the invention
[0010] FIG. 2 is a schematic illustration of a SCOL target and its
measurement procedure, according to the prior art.
[0011] FIG. 3 is a high-level flowchart illustrating a method,
according to some embodiments of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0012] In the following description, various aspects of the present
invention are described. For purposes of explanation, specific
configurations and details are set forth in order to provide a
thorough understanding of the present invention. However, it will
also be apparent to one skilled in the art that the present
invention may be practiced without the specific details presented
herein. Furthermore, well known features may have been omitted or
simplified in order not to obscure the present invention. With
specific reference to the drawings, it is stressed that the
particulars shown are by way of example and for purposes of
illustrative discussion of the present invention only, and are
presented in the cause of providing what is believed to be the most
useful and readily understood description of the principles and
conceptual aspects of the invention. In this regard, no attempt is
made to show structural details of the invention in more detail
than is necessary for a fundamental understanding of the invention,
the description taken with the drawings making apparent to those
skilled in the art how the several forms of the invention may be
embodied in practice.
[0013] Before at least one embodiment of the invention is explained
in detail, it is to be understood that the invention is not limited
in its application to the details of construction and the
arrangement of the components set forth in the following
description or illustrated in the drawings. The invention is
applicable to other embodiments that may be practiced or carried
out in various ways as well as to combinations of the disclosed
embodiments. Also, it is to be understood that the phraseology and
terminology employed herein are for the purpose of description and
should not be regarded as limiting.
[0014] Unless specifically stated otherwise, as apparent from the
following discussions, it is appreciated that throughout the
specification discussions utilizing terms such as "processing",
"computing", "calculating", "determining", "enhancing", "deriving"
or the like, refer to the action and/or processes of a computer or
computing system, or similar electronic computing device, that
manipulates and/or transforms data represented as physical, such as
electronic, quantities within the computing system's registers
and/or memories into other data similarly represented as physical
quantities within the computing system's memories, registers or
other such information storage, transmission or display devices. In
certain embodiments, illumination technology may comprise,
electromagnetic radiation in the visual range, ultraviolet or even
shorter wave radiation such as x rays, and possibly even particle
beams.
[0015] Embodiments of the present invention provide efficient and
economical methods and mechanism for scatterometry overlay (SCOL)
metrology measurements and thereby provide improvements to the
technological field of semiconductor metrology. Scatterometry
overlay (SCOL) measurement methods, systems and targets are
provided to enable efficient SCOL metrology with in-die targets.
Methods comprise generating a signal matrix by: illuminating a SCOL
target at multiple values of at least one illumination parameter,
and at multiple spot locations on the target, wherein the
illumination is at a NA (numerical aperture) >1/3 yielding a
spot diameter <1.mu., measuring interference signals of zeroth
and first diffraction orders, and constructing the signal matrix
from the measured signals with respect to the illumination
parameters and the spot locations on the target; and deriving a
target overlay by analyzing the signal matrix. The SCOL targets may
be reduced to be a tenth in size with respect to prior art targets,
as less and smaller target cells are required, and be easily set
in-die to improve the accuracy and fidelity of the metrology
measurements. The small spots, the use of varying illumination
parameters and quick spot scanning methods, enable using single
cells instead on pairs of cells with opposite predefined offsets,
and enable reducing the cell size together with the spot size
reduction.
[0016] FIGS. 1A and 1B are high-level schematic illustrations of a
SCOL target 110 and its measurement system 100, according to some
embodiments of the invention. System 100, e.g., a metrology system
or module therewithin, may be configured to illuminate SCOL target
110 having periodic structures 120A, 120B (e.g., gratings) using a
large NA (numerical aperture) illumination unit 130 (e.g., having
NA>1/3 such as any of NA=0.4, 0.5. 0.6, 0.7, 0.8, 0.9, or other
values--with orders -1, 0 and +1 at least partly overlapping 145A
in the pupil plane) resulting in corresponding small illumination
spots 136, e.g., smaller than 1.mu., or possibly between any of
250-1000 nm or 600-1000 nm. In FIG. 1A, SCOL target 110 is
illustrated in schematic cross-section view, with intermediate
layers between top periodic structure 120A and bottom periodic
structure 120B, and notation of illumination 135, reflection signal
(R.sub.0 denoting the zeroth order) and .+-.1 order diffracted
signals 145, denoted by T.sub..+-.1 and B.sub..+-.1 for top and
bottom .+-.1 diffraction orders, respectively. In FIG. 1B, SCOL
target 110 is illustrated in schematic top view, and may have an
offset (not shown) between periodic structures 120A, 120B.
[0017] System 100 may be configured to illuminate SCOL target 110
at a plurality of spot locations 136 on target 110, which may be
stepped along the measurement direction(s) of periodic structure(s)
120A, 120B of SCOL target 110 and possibly scanned along the
elements of periodic structure(s) 120A, 120B (perpendicular to the
measurement direction) for averaging the measured signals. Spot
locations 136 may be selected to be within a pitch of periodic
structure(s) 120A, 120B of SCOL target 110, as illustrated
schematically in FIG. 1B. It is noted that spot locations 136 may
be spread over two or more pitches, yet at least two of the spot
locations should be not equivalent with respect to the target
periodicity, to yield non-equivalent signals for analysis.
Selecting spot locations 136 within one (or two) target pitches
enables a significant reduction in target size, compared with prior
art that requires many target pitches to be covered by the large
prior art illumination spot.
[0018] System 100 further comprises a measurement unit 140 with
pupil plane sensor(s) configured to measure a corresponding
plurality of measurement signals 145 from multiple spot locations
136 on target 110. Signals 145 comprise interference signals of
zeroth and first order diffractions components of the illumination
from each spot location 136, as illustrated schematically by
overlaps 145A in FIGS. 1A and 1B. Such interference is due to using
small illumination spots 135 and measurement may utilize changes in
signal intensity to isolate or evaluate first order signal
fluctuations from background zeroth order reflections. SCOL targets
110 may comprise a single cell, from which all signals may be
derived and the corresponding overlay may be calculated. Analysis
of signals 145 may be carried out as taught by U.S. Patent
Application Publication No. 2017/0268869, which is incorporated
herein by reference in its entirety.
[0019] System 100 may be configured to carry out illumination 130
at least at two different illumination parameters (denoted as
"grey" SCOL), e.g., using multiple different wavelengths (e.g.,
three or more), using different focus and/or positions (possibly
involving scanning the target), different polarizations, etc., and
to derive the target overlay from an analysis of measured signals
145 with respect to the spot locations on target 110 and the
illumination parameters. It is noted that one, two, three or more
illumination parameters may be used in the measurements, in certain
embodiments, using three illumination parameter values was found to
be optimal in some cases with respect to measurement and overlay
derivation complexities.
[0020] System 100 further comprises a processing unit 155
configured to construct a signal matrix 150 from measured signals
145 with respect to the illumination parameters and the spot
locations on target 110, and to derive the target overlay by
analyzing signal matrix 150. As measurements employ multiple small
spots 135, having different illumination characteristics, to
multiple spot locations 136 on target 110 that yield interfered
(mixed) diffraction orders from corresponding signals
145--resulting signal matrix 150 may be used to derive and analyze
the signals 147 with respect to spot locations 136 and illuminating
characteristics to derive the target overlay.
[0021] System 100 may be further configured to calibrate signal
matrix 150 by performing or simulating measurements of SCOL targets
with known overlay values. For example, multiple reference targets,
possibly on reference wafer(s), with known overlays may be measured
by system 100 and the measurements may be used to generate a model
relating measurement results to the known overlays. Alternatively
or complementarily, simulations may be used to suggest relations
between overlays and signals, and possibly to optimize the
illumination parameters used (e.g., wavelengths values, other
illumination parameters) as well as spot size and NA, stepping and
scanning methods and parameters of spots 135 over target 110 etc.
System 100 may be further configured to create a model of signal
matrix 150 with respect to spot locations 136, illumination
parameters and target overlays. Calibration may be carried out in a
training phase or on-the-fly. Scanning targets 110 with small spots
135 may be carried out, e.g., by scanning over a length scale of
one target pitch (or, e.g., two target pitches), e.g., smaller than
1.mu..
[0022] In certain embodiments, target 110 may be designed to have
periodic structures with specified pitches along two measurement
directions, and system 100 may be configured to derive measurements
using the same cell for both directions, with corresponding signal
matrices 150 derived for each direction, possibly simultaneously,
and analyzed to derive respective overlays as disclosed above.
[0023] In various embodiments, a formalism may be used to derive
the relation between the overlay and the measurement results with
multiple illumination parameters, based e.g., on electromagnetic
modelling and/or simulation of optical path differences (OPDs),
that relate changes in the strength of the diffracted fields with
the changing illumination parameters--with respect to the overlay.
Following corresponding analysis, simulation and/or training,
direct relations may be established between the overlay and the
measurement results.
[0024] For example, the inventors have noted that the ratio of the
sum of differential signals to the difference of signal sums in the
two measurement wavelengths depends only on the difference between
the OPDs at the two wavelengths (or generally at the two
measurement conditions), and not on the OPDs themselves. Therefore,
in certain embodiments, this expression may be a stable parameter
between process variations. For example, the measurement signals
may be modelled while maintaining a relation between the
illumination parameters and intensity measurements and/or accuracy
metrics associated therewith.
[0025] In certain embodiments, landscape shifts with process
variation may be utilized to derive overlays and/or to decouple
between the overlay and target asymmetries, landscapes comprising
an at least partially continuous dependency of at least one
metrology metric on at least one parameter, as taught e.g., by U.S.
Application Publication Nos. 2016/0313658 and 2018/0023950,
incorporated herein by reference in their entirety. For example,
measurements may be carried out at flat and resonant regions of the
landscape to derive the overlay (and/or process variation). In
certain embodiments, opposite predetermined offsets may be set in
single target at different sites on the wafer, and the derivation
may take into account the relative effects of these intended
offsets.
[0026] In certain embodiments, a training phase may include
measuring the metrology measurement recipe over multiple sites
across the wafer, and modelling from the measurements, at least
partly, the relation between the changes in illumination parameters
and the changes in OPDs--which may then be used to derive the
overlays. For example, certain wavelength ranges may be used for
the measurements, with respect to certain ranges of changes in
OPD.
[0027] FIG. 2 is a schematic illustration of a SCOL target 80 and
its measurement procedure 90, according to the prior art. Prior art
SCOL targets 80 typically comprise at least two cells 80A, 80B in
each measurement direction, which comprise two or more periodic
structures in corresponding layers, which are displaced with
respect to each other by opposite predetermined offsets +f.sub.0
and -f.sub.0, illustrated schematically. Cells 80A, 80B are used to
extract the (unintended) overlay between the periodic structures
from measured diffraction signals from cells 80A, 80B. Measurements
90 are carried out by providing illumination and measurement
conditions which prevent overlap of the diffraction orders 65
(e.g., +1.sup.st, -1.sup.st) with the reflected illumination
(zeroth order) at the pupil plane of a respective sensor 60. The
required prior art illumination conditions (of illumination unit
70) include a small numerical aperture (NA) which creates a large
illumination spot 75 on cells 80A, 80B, and provides the required
diffraction order isolation on sensor 60. For example, small
illumination NA (e.g., NA=0.1, 0.2, 0.3 or other values smaller
than about a third--with orders -1, 0 and +1 not overlapping in the
pupil plane) may be configured to result in illumination spot 75
being 1.mu. or more, to ensure scattered orders separation. The
overlay is then calculated from the differential signal between the
cells 62. It is noted that large illumination spot 75 requires
prior art cells 80A, 80B to be large, and the minimal requirement
of two cells per direction (for providing the opposite
predetermined offsets .+-.f.sub.0) further increases the size of
prior art SCOL targets 80, reaching typically e.g.,
8.mu..times.8.mu. (cell size) or larger.
[0028] Advantageously, the inventors have found out that in
contrast to prior art, a single cell approach to SCOL is attainable
using a small illumination spot and multiple illumination
parameter(s) values, such as multiple wavelengths instead of using
prior art cell pairs with opposite predetermined offsets. For
example, modification of illumination parameters was found to be
related to fluctuation in measured signal intensities (and/or
related accuracy metrics), which were then used to derive data
concerning the respective measured targets. Advantageously, the
disclosed approach reduces significantly the real estate required
for the metrology target, possibly enabling in-die metrology--due
to using a single cell instead of two cells for each measurement
direction and as the cells can be made smaller due to the use of a
small illumination spot. It is noted that that significant
reduction in real estate is achieved at the cost of requiring
measurements with multiple measurement parameters and possibly
target scanning (which may take longer and require illumination
modification) and possibly at the cost of making the calibration
more empirical in nature, as the derivation of the overlay from the
measurement data is less straightforward than in the prior art. The
derivation of the overlay from the calibrated measurements may be
carried out analytically, e.g., using simulations, in a training
phase, using calibration wafer(s) and/or using simulation. It is
emphasized though, that following initial calibration and training,
the derivation of the overlay is expected to be at least as fast as
in the prior art.
[0029] According to initial modelling, in certain embodiments, SCOL
targets 110 may be significantly smaller than prior art SCOL
targets 80--due to their reduction to one cell 115 for each
measurement direction (or possibly using the same cell for both
directions) and optional reduction of cell size due to using
smaller spot 135. For example, single cell targets 110 may be four
or less pitch bars (periodic structure elements) wide, possibly one
or two pitch bars wide. As a result, SCOL targets 110 may be down
to ten times smaller than prior art SCOL targets 80 (e.g., measure
2.mu..times.2.mu. or smaller, vs. 8.mu..times.8.mu. or larger,
respectively). Periodic structures 120A, 120B in multiple layers of
SCOL target 110 may be aligned, as prior art predefined offsets may
not be necessary in the current invention (they are used in the
prior art to provide differential signal 62, which may be presently
replaced by signal matrix 150). It is noted that multiple
illumination characteristics may be used in various embodiments to
extract the overlay from the different responses of periodic
structures 120A, 120B, rather than the predetermined offsets used
in the prior art.
[0030] Advantageously, disclosed small SCOL targets 110 are readily
designed as in-die targets or marks, providing higher metrology
accuracy and fidelity with respect to the semiconductor devices on
the wafer.
[0031] In various embodiments, disclosed systems 100, targets 110
and methods 200 may increase the illumination NA to provide signals
including zeroth and first order mixing, which is utilized by spot
scanning to detect the resulting modulation (as the spot is scanned
and/or as the illumination characteristics are changed) in the
overlapping orders over the pupil area. Measurements with multiple
wavelengths include information for deriving the overlay without
the need for an additional cell. System 100 may implement fast spot
scanning and fast wavelength switching so that the data required
for the disclosed measurements is collected with minimal or no MAM
(move-acquire-measure) penalty relative to specified requirements,
and thereby enable in-die small targets required by customers.
[0032] FIG. 3 is a high-level flowchart illustrating a method 200,
according to some embodiments of the invention. The method stages
may be carried out with respect to SCOL targets 110 and/or
measurement systems 100 described above, which may optionally be
configured to implement method 200. Method 200 may be at least
partially implemented by at least one computer processor, e.g., in
a metrology module. Certain embodiments comprise computer program
products comprising a computer readable storage medium having
computer readable program embodied therewith and configured to
carry out the relevant stages of method 200. Certain embodiments
comprise metrology measurements derived by embodiments of method
200. Method 200 may comprise the following stages, irrespective of
their order.
[0033] Scatterometry overlay (SCOL) measurement method 200
comprises generating a signal matrix (stage 240) by: illuminating a
SCOL target, wherein the illumination is at a large NA (numerical
aperture) >1/3 yielding a small spot diameter <1.mu. (stage
210), at multiple spot locations on the target (stage 220), and at
multiple values of at least one illumination parameter (stage 230),
e.g., three or more wavelengths, and measuring interference signals
of zeroth and first diffraction orders (stage 215). The signal
matrix is then constructed from the measured signals with respect
to the illumination parameters and the spot locations on the target
(stage 240). Method 200 further comprises deriving a target overlay
by analyzing the signal matrix, e.g., from an analysis of the
measured signals with respect to the spot locations on the target
and the illumination parameters (stage 250).
[0034] The SCOL target may comprise at least one periodic structure
and the multiple spot locations may be within one pitch (or two
pitches) of the at least one periodic structure, so that
non-equivalent spot locations with respect to the periodicity of
the target are used. The spot locations on the target may be set
within the target pitch along a measurement direction of the at
least one periodic structure, changing the spot locations within
the target pitch (stage 222), and the measured signal may be
averaged in a direction perpendicular to the measurement direction,
e.g., by scanning the spots along the target elements (stage
224).
[0035] In certain embodiments, SCOL measurement method 200 may
further comprise calibrating the signal matrix by performing or
simulating measurements of SCOL targets with known overlay values
(stage 260).
[0036] In certain embodiments, SCOL measurement method 200 may
further comprise carrying out a training phase of measuring a
corresponding metrology measurement recipe over multiple sites
across the wafer (stage 270).
[0037] In certain embodiments, SCOL measurement method 200 may
further comprise creating a model of the signal matrix with respect
to the spot locations, illumination parameters and target overlays
(stage 280).
[0038] In certain embodiments, method 200 as a SCOL target design
method may comprise designing the SCOL target as a single cell
target and/or as being 2.mu..times.2.mu. or smaller, and possibly
placed in-die on a corresponding wafer. In certain embodiments,
method 200 may further comprise configuring the periodic structures
of the target to be aligned and/or be at most four, three, or two
pitch bars (periodic structure elements) wide, possibly even one
pitch wide. Certain embodiments comprise target design files of
SCOL targets 110 and/or SCOL targets designed by the SCOL target
design method.
[0039] Aspects of the present invention are described above with
reference to flowchart illustrations and/or portion diagrams of
methods, apparatus (systems) and computer program products
according to embodiments of the invention. It will be understood
that each portion of the flowchart illustrations and/or portion
diagrams, and combinations of portions in the flowchart
illustrations and/or portion diagrams, can be implemented by
computer program instructions. These computer program instructions
may be provided to a processor of a general-purpose computer,
special purpose computer, or other programmable data processing
apparatus to produce a machine, such that the instructions, which
execute via the processor of the computer or other programmable
data processing apparatus, create means for implementing the
functions/acts specified in the flowchart and/or portion diagram or
portions thereof.
[0040] These computer program instructions may also be stored in a
computer readable medium that can direct a computer, other
programmable data processing apparatus, or other devices to
function in a particular manner, such that the instructions stored
in the computer readable medium produce an article of manufacture
including instructions which implement the function/act specified
in the flowchart and/or portion diagram or portions thereof.
[0041] The computer program instructions may also be loaded onto a
computer, other programmable data processing apparatus, or other
devices to cause a series of operational steps to be performed on
the computer, other programmable apparatus or other devices to
produce a computer implemented process such that the instructions
which execute on the computer or other programmable apparatus
provide processes for implementing the functions/acts specified in
the flowchart and/or portion diagram or portions thereof.
[0042] The aforementioned flowchart and diagrams illustrate the
architecture, functionality, and operation of possible
implementations of systems, methods and computer program products
according to various embodiments of the present invention. In this
regard, each portion in the flowchart or portion diagrams may
represent a module, segment, or portion of code, which comprises
one or more executable instructions for implementing the specified
logical function(s). It should also be noted that, in some
alternative implementations, the functions noted in the portion may
occur out of the order noted in the figures. For example, two
portions shown in succession may, in fact, be executed
substantially concurrently, or the portions may sometimes be
executed in the reverse order, depending upon the functionality
involved. It will also be noted that each portion of the portion
diagrams and/or flowchart illustration, and combinations of
portions in the portion diagrams and/or flowchart illustration, can
be implemented by special purpose hardware-based systems that
perform the specified functions or acts, or combinations of special
purpose hardware and computer instructions.
[0043] In the above description, an embodiment is an example or
implementation of the invention. The various appearances of "one
embodiment", "an embodiment", "certain embodiments" or "some
embodiments" do not necessarily all refer to the same embodiments.
Although various features of the invention may be described in the
context of a single embodiment, the features may also be provided
separately or in any suitable combination. Conversely, although the
invention may be described herein in the context of separate
embodiments for clarity, the invention may also be implemented in a
single embodiment. Certain embodiments of the invention may include
features from different embodiments disclosed above, and certain
embodiments may incorporate elements from other embodiments
disclosed above. The disclosure of elements of the invention in the
context of a specific embodiment is not to be taken as limiting
their use in the specific embodiment alone. Furthermore, it is to
be understood that the invention can be carried out or practiced in
various ways and that the invention can be implemented in certain
embodiments other than the ones outlined in the description
above.
[0044] The invention is not limited to those diagrams or to the
corresponding descriptions. For example, flow need not move through
each illustrated box or state, or in exactly the same order as
illustrated and described. Meanings of technical and scientific
terms used herein are to be commonly understood as by one of
ordinary skill in the art to which the invention belongs, unless
otherwise defined. While the invention has been described with
respect to a limited number of embodiments, these should not be
construed as limitations on the scope of the invention, but rather
as exemplifications of some of the preferred embodiments. Other
possible variations, modifications, and applications are also
within the scope of the invention. Accordingly, the scope of the
invention should not be limited by what has thus far been
described, but by the appended claims and their legal
equivalents.
* * * * *