U.S. patent application number 11/956319 was filed with the patent office on 2009-06-18 for carrier apparatus and method for shaped sheet materials.
This patent application is currently assigned to Silicon Genesis Corporation. Invention is credited to Sien Kang, Ky Phan, LU TIAN.
Application Number | 20090152162 11/956319 |
Document ID | / |
Family ID | 40751807 |
Filed Date | 2009-06-18 |
United States Patent
Application |
20090152162 |
Kind Code |
A1 |
TIAN; LU ; et al. |
June 18, 2009 |
CARRIER APPARATUS AND METHOD FOR SHAPED SHEET MATERIALS
Abstract
A carrier apparatus for holding a shaped sheet material includes
a first frame structure with a first front surface including a
first outer peripheral region and a first inner peripheral region
separated by a first step. The apparatus further includes a second
frame structure with a second front surface including a second
outer peripheral region and a second inner peripheral region
separated by a second step. The second front surface is configured
to engage with the first front surface so that the second outer
peripheral region is at least partially in contact with the first
outer peripheral region and the second step circumferentially mates
the first step with the second inner peripheral region opposing to
the first inner peripheral region by a gap. The carrier apparatus
further includes one or more locking mechanisms and a shaped wing
structure extended from outer peripheral edge of the first frame
structure.
Inventors: |
TIAN; LU; (Milpitas, CA)
; Kang; Sien; (Dublin, CA) ; Phan; Ky;
(Santa Clara, CA) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER, EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
Silicon Genesis Corporation
San Jose
CA
|
Family ID: |
40751807 |
Appl. No.: |
11/956319 |
Filed: |
December 13, 2007 |
Current U.S.
Class: |
206/710 |
Current CPC
Class: |
H01L 21/67353 20130101;
H01L 21/67373 20130101 |
Class at
Publication: |
206/710 |
International
Class: |
B65D 85/90 20060101
B65D085/90 |
Claims
1. A carrier apparatus for holding a shaped sheet material, the
apparatus comprising: a first frame structure having a first front
surface including a first outer peripheral region and a first inner
peripheral region separated by a first step, the first inner
peripheral region being characterized by a width of a ledge
extended circumferentially from the first step and one or more
athwart dimensions from the first step at one side of the first
inner peripheral region to the first step at an opposing side of
the first inner peripheral region in one or more diagonal
orientations; a second frame structure having a second front
surface including a second outer peripheral region and a second
inner peripheral region separated by a second step, the second
front surface being configured to engage with the first front
surface at a close position so that the second outer peripheral
region is at least partially in contact with the first outer
peripheral region and the second step circumferentially mates the
first step with the second inner peripheral region opposing to the
first inner peripheral region by a gap; one or more locking
mechanisms to withhold the second frame structure engaged with the
first frame structure; and a shaped wing structure integrally
extended from outer peripheral edge of the first frame
structure.
2. The carrier apparatus of claim 1 wherein the first step moves
down from the first outer peripheral region to the first inner
peripheral region as the first front surface faces up and the
second step moves up from the second outer peripheral region to the
second inner peripheral region as the second front surface faces
up.
3. The carrier apparatus of claim 2 wherein the first step is
associated with a first step height and the second step is
associated with a second step height, the second step height is
smaller than the first step height.
4. The carrier apparatus of claim 3 wherein a difference between
the first step height and the second step height in the close
position with the second inner peripheral region opposing the first
inner peripheral region is substantially equal to the gap.
5. The carrier apparatus of claim 4 wherein the gap is bigger than
a thickness of the shaped sheet material by a predetermined
margin.
6. The carrier apparatus of claim 5 wherein the thickness of the
shaped sheet material comprises a range from 10 .mu.m to 200
.mu.m.
7. The carrier apparatus of claim 1 wherein the one or more athwart
dimensions from the first step at one side of the first inner
peripheral region to the first step at an opposing side of the
first inner peripheral region in one or more diagonal orientations
are configured to be substantially equal to or bigger than one or
more lateral dimensions of the shaped sheet material so that the
shaped sheet material can be circumferentially enclosed within the
first step with at least one or more peripheral portions of the
shaped sheet material being partially supported by the width of the
ledge of the first inner peripheral region.
8. The carrier apparatus of claim 7 wherein the width of the ledge
of the first inner peripheral region comprises a distance in
certain orientation equal to about 5% of an athwart dimension in
that orientation.
9. The carrier apparatus of claim 7 wherein the one or more athwart
dimensions comprise about 50 millimeters or greater, or 100
millimeters or bigger, or about 125 millimeters or bigger, or about
156 millimeters or bigger.
10. The carrier apparatus of claim 1 wherein the one or more
locking mechanisms comprise one or more screws at predetermined
corner locations, or one or more clips at predetermined locations
of the first outer peripheral region and the second outer
peripheral region, or one or more combinations of hinges and
latches at predetermined locations of the first outer peripheral
region and the second outer peripheral region.
11. The carrier apparatus of claim 1 wherein the shaped wing
structure integrally extended from a periphery of the first frame
structure comprises a substantially rounded shape with a diameter
ranging from 4 inches to 12 inches and a thickness of about 1
millimeter or smaller.
12. The carrier apparatus of claim 1 wherein the first frame
structure and the second frame structure are made of a material
selected from Teflon, PVDF (Polyvinylidene Difluoride), PEEK
(Polyetheretherketones), PET (polyethylene terephthalate),
polyimide, quartz, and aluminum, molybdenum, anodized aluminum,
stainless steel, and metal alloy comprising nickel, molybdenum,
chromium, cobalt, iron, copper, manganese, titanium, zirconium,
aluminum, carbon, and tungsten.
13. The carrier apparatus of claim 1, and further comprises a first
cover circumferentially coupled to the first inner peripheral
region and a second cover circumferentially coupled to the second
inner peripheral region.
14. A carrier apparatus for holding a shaped sheet material, the
apparatus comprising: a first C-like frame member including two
first arm sections each with a first length from a first base to a
first end integrally extended from a first middle section, the two
first arm sections each including two side-ridges with
substantially first half of the first length from the first end, a
middle slot formed between the two side ridges, and a middle hole
extended further from the middle slot with a same lateral dimension
and substantially second half of the first length; a second C-like
frame member including two second arm sections each with a second
length from a second base to a second end integrally extended from
a second middle section, the two second arm sections each including
a middle rod with substantially first half of the second length
from the second end and two side slots further extended
substantially second half the second length, the second length
being substantially equal to the first length, the middle rod being
configured to slidingly mate with the middle slot and further with
the middle hole till a close position as the two side slots fully
engage with the two side-ridges; a first trench formed through a
first inner side of the first C-like frame member with a
predetermined depth, the first trench being offset the middle hole
and two side ridges; and a second trench formed through a second
inner side of the second C-like frame member with substantially the
same predetermined depth, the second trench and the first trench
being connected at the close position.
15. The carrier apparatus of claim 14, and further comprising a
shaped wing structure extended from outer peripheral edges of both
the first C-like frame member and the second C-like frame
member.
16. A carrier cassette for a plurality of carrier apparatus, the
carrier cassette comprising: a length of a bulk structure with a
U-like cross section including a bottom surface and an inner
surface, the inner surface including a plurality of slots disposed
perpendicular to the length of the bulk structure with a
predetermined spacing between each other, each of the plurality of
slots being configured to be inserted with a carrier apparatus, the
carrier apparatus comprising: a first frame structure having a
first front surface including a first outer peripheral region and a
first inner peripheral region separated by a first step, the first
inner peripheral region being characterized by a width of a ledge
extended circumferentially from the first step and one or more
athwart dimensions from the first step at one side of the first
inner peripheral region to the first step at an opposing side of
the first inner peripheral region in one or more diagonal
orientations; a second frame structure having a second front
surface including a second outer peripheral region and a second
inner peripheral region separated by a second step, the second
front surface being configured to engage with the first front
surface at a close position so that the second outer peripheral
region is at least partially in contact with the first outer
peripheral region and the second step circumferentially mates the
first step with the second inner peripheral region opposing to the
first inner peripheral region by a gap; one or more locking
mechanisms to secure the second frame structure engaged with the
first frame structure; and a shaped wing structure integrally
extended from outer peripheral edge of the first frame structure;
one or more holes disposed at the bottom portion of each of the
plurality of slots penetrating through the bottom surface.
17. A method for handling a shaped sheet material, the method
comprising: providing a shaped sheet material characterized by one
or more lateral dimensions and a thickness; providing a carrier
apparatus adapted to the shaped sheet material based on at least
information of the one or more lateral dimensions and the
thickness, the carrier apparatus comprising: a first frame
structure having a first front surface including a first outer
peripheral region and a first inner peripheral region separated by
a first step, the first inner peripheral region being characterized
by a width of a ledge extended circumferentially from the first
step and one or more athwart dimensions from the first step at one
side of the first inner peripheral region to the first step at an
opposing side of the first inner peripheral region in one or more
diagonal orientations; p2 a second frame structure having a second
front surface including a second outer peripheral region and a
second inner peripheral region separated by a second step, the
second front surface being configured to engage with the first
front surface at a close position so that the second outer
peripheral region is at least partially in contact with the first
outer peripheral region and the second step circumferentially mates
the first step with the second inner peripheral region opposing to
the first inner peripheral region by a gap; one or more locking
mechanisms to withhold the second frame structure engaged with the
first frame structure; and a shaped wing structure integrally
extended from outer peripheral edge of the first frame structure;
exposing the first front surface; loading the shaped sheet material
onto the first inner peripheral region; disposing the second frame
structure to mate the first frame structure so that the second
front surface engages with the first front surface at the close
position of the carrier apparatus; securing the engaged first frame
structure and the second frame structure; and transferring the
carrier apparatus to process the shaped sheet material held
therein.
18. The method of claim 17 wherein the shaped sheet material
comprises a deformable thin wafer produced by cleaving a bulk
material including ingots of single-crystalline or polycrystalline
silicon, or germanium, or III/V group compound semiconductor.
19. The method of claim 17 wherein the one or more lateral
dimensions of the shaped deformable sheet material comprises about
50 mm or bigger, or 100 mm or bigger, or about 125 mm or bigger, or
about 156 mm or bigger.
20. The method of claim 17 wherein the thickness of the shaped
deformable sheet material comprises a range from 10 .mu.m to 200
.mu.m.
21. The method of claim 17 wherein providing a carrier apparatus
for the shaped sheet material comprises determining the first frame
structure and the second frame structure adaptive to the shaped
sheet material based on at least the one or more lateral dimensions
and the thickness.
22. The method of claim 17 wherein loading the shaped sheet
material can be performed by an electrostatic chuck or a vacuum
chuck.
23. The method of claim 17 wherein securing the engaged first frame
structure and the second frame structure comprises utilizing the
one or more locking mechanisms including one or more clips, or one
or more screws, or one or more springs, or one or more latches.
24. The method of claim 17 wherein transferring the carrier
apparatus to process the shaped sheet material held therein
comprises loading a plurality of carrier apparatuses, each holding
a shaped sheet material, respectively into a carrier cassette
including a plurality of slots with a width matched the shaped wing
structure and inter-slot spacing adapted to a total thickness of
the carrier apparatus; transferring the carrier cassette including
the plurality of carrier apparatuses into a processing system; and
simultaneously processing both sides of each shaped sheet material
held within each carrier.
25. The method of claim 24 wherein simultaneously processing both
sides of each shaped sheet material held within each carrier
comprises performing a wet cleaning process, or a chemical etching
process, or a deposition process, or a thermal annealing process,
or a material characterization process.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] Not applicable
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED
RESEARCH OR DEVELOPMENT
[0002] Not applicable
REFERENCE TO A "SEQUENCE LISTING," A TABLE, OR A COMPUTER PROGRAM
LISTING APPENDIX SUBMITTED ON A COMPACT DISK
[0003] Not applicable
BACKGROUND OF THE INVENTION
[0004] The present invention relates generally to technique for
handling shaped sheet materials. More particularly, the present
invention provides a carrier apparatus including a top frame
structure and a bottom frame structure configured to be engaged
with each other and method of using the carrier apparatus for
holding a shaped sheet material to perform any process or storage.
Merely by way of example, the invention has been applied for
handling deformable silicon sheets or thin wafers of 10 to 200
microns in thickness and 50 millimeters and greater in lateral
dimension produced by a layer transfer technique based on RFQ
linear accelerator system and used for a variety of applications
including photovoltaic cells. But it will be recognized that the
invention has a wider range of applicability.
[0005] From the beginning of time, human beings have relied upon
the "sun" to derive almost all useful forms of energy. Such energy
comes from petroleum, radiant, wood, and various forms of thermal
energy. As merely an example, human being have relied heavily upon
petroleum sources such as coal and gas for much of their needs.
Unfortunately, such petroleum sources have become depleted and have
lead to other problems. As a replacement, in part, solar energy has
been proposed to reduce our reliance on petroleum sources. As
merely an example, solar energy can be derived from "solar cells"
commonly made of silicon.
[0006] The silicon solar cell generates electrical power when
exposed to solar radiation from the sun. The radiation interacts
with atoms of the silicon and forms electrons and holes that
migrate to p-doped and n-doped regions in the silicon body and
create voltage differentials and an electric current between the
doped regions. Depending upon the application, solar cells have
been integrated with concentrating elements to improve efficiency.
As an example, solar radiation accumulates and focuses using
concentrating elements that direct such radiation to one or more
portions of active photovoltaic materials. Although effective,
these solar cells still have many limitations.
[0007] As merely an example, solar cells rely upon starting
materials such as silicon. Such silicon is often made using either
polysilicon (i.e. polycrystalline silicon) and/or single crystal
silicon materials. These materials are often difficult to
manufacture. Polysilicon cells are often formed by manufacturing
polysilicon plates. Although these plates may be formed
effectively, they do not possess optimum properties for highly
effective solar cells. Single crystal silicon has suitable
properties for high grade solar cells. Such single crystal silicon
is, however, expensive and is also difficult to use for solar
applications in an efficient and cost effective manner.
Additionally, both polysilicon and single-crystal silicon materials
suffer from material losses during conventional manufacturing
called "kerf loss", where the sawing process used for cutting the
plates with thickness ranging from 10 .mu.m to 200 .mu.m from bulk
materials eliminates as much as 40% and even up to 60% of the
starting material from a cast or grown boule and singulate the
material into a wafer form factor. This is a highly inefficient
method of preparing thin polysilicon or single-crystal silicon
plates for solar cell use.
[0008] Numerous drawbacks of the conventional sawing process can be
overcome using a novel layer transfer technique based on a cost
effective linear accelerator system to perform a high energy
ion-beam implantation process for producing transferable sheet
materials or thin wafers. For example, the layer transfer technique
in association with a linear accelerator system has been described
in a co-assigned U.S. patent application Ser. No. 11/935,197 by
Francois J Henley et al., and titled "METHOD AND STRUCTURE FOR
THICK LAYER TRANSFER USING A LINEAR ACCELERATOR", filed on Nov. 5,
2007. The deformable sheet materials made from bulk semiconductors
may be further processed for applications such as photovoltaic
devices, 3D MEMS or integrated circuits, IC packaging,
semiconductor devices, silicon carbide and gallium nitride films
for semiconductor and optoelectronic applications, any combination
of these, and others. In particular, single crystal silicon sheets
or thin wafers for highly efficient photovoltaic cells can be
formed very cost-effectively with the desired form factor (for
example, 10 .mu.m-200 .mu.m thickness with a area size from 10
cm.times.10 cm to upwards of 1 m.times.1 m or more for polysilicon
films/plates). Merely as an example, these silicon sheets can be
formed from a single ingot, e.g., silicon boule and repeated to
successively cleave one slice after another (similar to cutting
slices of bread from a baked loaf) according to a specific
embodiment. Because of the relative thin thickness (200 microns or
less) of these sheet materials, they are substantially deformable
especially when the lateral dimension becomes 50 mm or larger.
Therefore, traditional wafer carrier/cassette does not suit for
holding such deformable sheet materials. The state-of-art technique
for handling such thin silicon wafers may rely on using an
electrostatic chuck or a vacuum chuck which clamps at least one
side of the wafer by electrostatic force or pressure force.
However, a slight malfunction of chucking and dechucking sequences
may changes the forces that are not delicate enough to avoid
damages to these deformable silicon sheets or thin wafers.
Additionally, the usage of chucking method requires substantial
contact of at least one side the sheet or thin wafer. This also
causes easy contamination and inconvenience for cleaning and other
processing. Accordingly a carrier apparatus and method for holding
the deformable sheet materials are highly desired.
SUMMARY OF THE INVENTION
[0009] The present invention relates generally to technique for
handling shaped sheet materials. More particularly, the present
invention provides a carrier apparatus including a top frame
structure and a bottom frame structure configured to be engaged
with each other and method of using the carrier apparatus for
holding a shaped sheet material to perform any process or storage.
Merely by way of example, the invention has been applied for
handling deformable silicon sheets or thin wafers of 10 to 200
microns in thickness and 50 millimeters and greater in lateral
dimension produced by a layer transfer technique based on RFQ
linear accelerator system and used for a variety of applications
including photovoltaic cells. But it will be recognized that the
invention has a wider range of applicability.
[0010] Because the thickness of the sheet material is in a range
from 10 to 200 microns, the sheet material is likely to be
deformable and is susceptible to handling related damage. According
to certain embodiments of the present invention, a carrier
apparatus with one or more frame structures is provided for safe
and convenient handling of such sheet materials. In particular, the
carrier apparatus can have a top frame structure and a bottom frame
structure that can be mutually engaged to secure the shaped sheet
material in between. In one embodiment, the mating surface of the
bottom frame structure can have a stepped inner peripheral region
adapted to enclose and hold the shaped sheet material. Then the
mating surface of the top frame structure is engaged with the
mating surface of the bottom frame structure so that the shaped
sheet material is held in. It is followed by completing a locking
mechanism to couple the top frame structure and the bottom frame
structure together. In another embodiment, the carrier apparatus
can have two half frame members that can be engaged together to
form a closed loop, each half frame members including a cut-in slot
on its inner surface configured to receive a shaped sheet material.
The two half frame member can be engaged together by using sliding
slot/hole design in one embodiment. A locking mechanism for
coupling two half frame members can be used for securing the loaded
shaped sheet material. In a specific embodiment, one or two frame
structures include a shaped wing structure extended from outer
peripheral edges for convenience of storing and transporting the
carrier apparatus. Certain embodiments of the invention provides a
carrier cassette for loading a plurality of those carrier apparatus
holding shaped sheet materials, so that multiple sheet material can
be processed, transported, stored, or shipped in groups.
[0011] In a specific embodiment, the present invention provides a
carrier apparatus for holding a shaped sheet material. The
apparatus includes a first frame structure having a first front
surface including a first outer peripheral region and a first inner
peripheral region separated by a first step. The first inner
peripheral region is characterized by a width of a ledge extended
circumferentially from the first step and one or more athwart
dimensions from the first step at one side of the first inner
peripheral region to the first step at an opposing side of the
first inner peripheral region in one or more diagonal orientations.
The apparatus further includes a second frame structure
characterized by a second front surface including a second outer
peripheral region and a second inner peripheral region separated by
a second step. The second front surface is configured to engage
with the first front surface at a close position so that the second
outer peripheral region is at least partially in contact with the
first outer peripheral region and the second step circumferentially
mates the first step with the second inner peripheral region
opposing to the first inner peripheral region by a gap.
Additionally, the apparatus includes one or more locking mechanisms
to withhold the second frame structure engaged with the first frame
structure. Furthermore, the carrier apparatus includes a shaped
wing structure integrally extended from outer peripheral edge of
the first frame structure.
[0012] In another specific embodiment, the present invention
includes a carrier apparatus for holding a shaped sheet material.
The apparatus includes a first C-like frame member including two
first arm sections each with a first length from a first base to a
first end integrally extended from a first middle section. Each of
the two first arm sections includes two side-ridges with
substantially first half of the first length from the first end. A
middle slot is formed between the two side ridges. A middle hole is
extended further from the middle slot with a same lateral dimension
and substantially second half of the first length. Additionally,
the apparatus includes a second C-like frame member including two
second arm sections each with a second length from a second base to
a second end integrally extended from a second middle section. Each
of the two second arm sections includes a middle rod with
substantially first half of the second length from the second end
and two side slots further extended substantially second half the
second length. The second length is substantially equal to the
first length. The middle rod is configured to slidingly mate with
the middle slot and further with the middle hole till a close
position as the two side slots fully engage with the two
side-ridges. Moreover, the apparatus includes a first trench formed
through a first inner side of the first C-like frame member with a
predetermined depth and cross-section shape. The first trench is
offset the middle hole and two side ridges. Furthermore, the
apparatus includes a second trench formed through a second inner
side of the second C-like frame member with substantially the same
predetermined depth and the cross-section shape. The second trench
and the first trench are connected at the close position.
[0013] In an alternative embodiment, the present invention provides
a carrier cassette for a plurality of carrier apparatus. The
carrier cassette includes a length of a bulk structure with a
U-like cross section including a bottom surface and an inner
surface. The inner surface includes a plurality of slots disposed
perpendicular to the length of the bulk structure with a
predetermined spacing between each other. Each of the plurality of
slots is configured to be inserted with a carrier apparatus. The
carrier apparatus includes a first frame structure having a first
front surface including a first outer peripheral region and a first
inner peripheral region separated by a first step. The first inner
peripheral region is characterized by a width of a ledge extended
circumferentially from the first step and one or more athwart
dimensions from the first step at one side of the first inner
peripheral region to the first step at an opposing side of the
first inner peripheral region in one or more diagonal orientations.
The carrier apparatus also includes a second frame structure
characterized by a second front surface including a second outer
peripheral region and a second inner peripheral region separated by
a second step. The second front surface is configured to engage
with the first front surface at a close position so that the second
outer peripheral region is at least partially in contact with the
first outer peripheral region and the second step circumferentially
mates the first step with the second inner peripheral region
opposing to the first inner peripheral region by a gap. The carrier
apparatus further includes one or more locking mechanisms to secure
the second frame structure engaged with the first frame structure.
Furthermore, the carrier apparatus includes a shaped wing structure
integrally extended from outer peripheral edge of the first frame
structure. The carrier cassette additionally includes one or more
holes disposed at the bottom portion of each of the plurality of
slots penetrating through the bottom surface. In one embodiment,
the carrier cassette further includes one or more handles.
[0014] In yet another alternative embodiment, the present invention
provides a method for handling a shaped sheet material. The method
includes providing a shaped sheet material characterized by one or
more lateral dimensions and a thickness and providing a carrier
apparatus adapted to the shaped sheet material based on at least
information of the one or more lateral dimensions and the
thickness. The carrier apparatus includes at least a first frame
structure having a first front surface including a first outer
peripheral region and a first inner peripheral region separated by
a first step. The first inner peripheral region is characterized by
a width of a ledge extended circumferentially from the first step
and one or more athwart dimensions from the first step at one side
of the first inner peripheral region to the first step at an
opposing side of the first inner peripheral region in one or more
diagonal orientations. The carrier apparatus also includes a second
frame structure characterized by a second front surface including a
second outer peripheral region and a second inner peripheral region
separated by a second step. The second front surface is configured
to engage with the first front surface at a close position so that
the second outer peripheral region is at least partially in contact
with the first outer peripheral region and the second step
circumferentially mates the first step with the second inner
peripheral region opposing to the first inner peripheral region by
a gap. The carrier apparatus further includes one or more locking
mechanisms to secure the second frame structure engaged with the
first frame structure and a shaped wing structure integrally
extended from outer peripheral edge of the first frame structure.
Additionally, the method includes exposing the first front surface
and loading the shaped sheet material onto the first inner
peripheral region. Moreover, the method includes disposing the
second frame structure to mate the first frame structure so that
the second front surface engages with the first front surface at
the close position of the carrier apparatus and securing the
engaged first frame structure and the second frame structure.
Furthermore, the method includes transferring the carrier apparatus
to process the shaped sheet material held therein. In one
embodiment, both sides of the shaped sheet material can be
processed simultaneously.
[0015] Additional embodiments and features are set forth in part in
the description that follows, and in part will become apparent to
those skilled in the art upon examination of the specification or
may be learned by practice of the invention. The features and
advantages of the invention may be realized and attained by means
of the machinery, instrumentalities, combinations, and methods
described in the specification as well as in claims herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1A is a schematic diagram of a top view of a carrier
apparatus for a shaped sheet material in an open position according
to an embodiment of the present invention;
[0017] FIG. 1B shows an AA' cross sectional view of a top frame
section and a BB' cross sectional view of a bottom frame section
cutting along the directions marked in FIG. 1A;
[0018] FIG. 1C is a schematic diagram of a top view of the carrier
apparatus in FIG. 1A loaded with a shaped sheet material into the
bottom frame section according to an embodiment of the present
invention;
[0019] FIG. 1D is a schematic diagram of a top view of the carrier
apparatus in a close position with loaded shaped sheet material
according to an embodiment of the present invention, including an
HH' cross sectional view;
[0020] FIG. 1E is a schematic diagram of a carrier apparatus with a
cover circumferentially coupled to each frame structure according
to another embodiment of the present invention;
[0021] FIG. 2 is simplified flowchart showing a method for handling
a shaped sheet material according to an alternative embodiment of
the present invention;
[0022] FIG. 3A is an exemplary top view of a carrier apparatus with
two frame members at an open position for a shaped sheet material
according to another embodiment of the present invention, including
a YY' cross sectional view of the frame member with a slot on inner
surface;
[0023] FIG. 3B is an exemplary top view of the carrier apparatus in
FIG. 3A at a close position according to another embodiment of the
present invention;
[0024] FIG. 3C is an exemplary top view of the carrier apparatus in
FIGS. 3A and 3B at a close position with a shaped sheet material
being held therein according to another embodiment of the present
invention;
[0025] FIG. 4 is a simplified diagram showing a carrier apparatus
with a top view of a first frame structure having an extended wing
structure and a mating second frame structure for holding a shaped
sheet material according to an embodiment of the present
invention;
[0026] FIG. 5A is a prospect view of a carrier cassette with a
plurality of matched slots each configured to hold a carrier
apparatus according to an alternative embodiment of the present
invention; and
[0027] FIG. 5B is a prospect view of the carrier cassette in FIG.
5A holding two carrier apparatuses each holding a shaped sheet
material therein according to an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0028] The present invention relates generally to technique for
handling shaped sheet materials. More particularly, the present
invention provides a carrier apparatus including a top frame
structure and a bottom frame structure configured to be engaged
with each other and method of using the carrier apparatus for
holding a shaped sheet material to perform any process or storage.
Merely by way of example, the invention has been applied for
handling deformable silicon sheets or thin wafers of 10 to 200
microns in thickness and 50 millimeters and greater in lateral
dimension produced by a layer transfer technique based on RFQ
linear accelerator system and used for a variety of applications
including photovoltaic cells. But it will be recognized that the
invention has a wider range of applicability.
[0029] FIG. 1A is a schematic diagram of a top view of a carrier
apparatus for a shaped sheet material in an open position according
to an embodiment of the present invention. This diagram is merely
an example, which should not unduly limit the scope of the claims
herein. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications. As shown, the carrier
apparatus 100 including two frame structures (110 and 160) coupled
each other by one or more hinges (130) is illustrated in an open
position. A frame structure 110 in bottom part of the FIG. 1A
reveals a surface in a closed loop including an outer peripheral
region 112 and an inner peripheral region 114 separated by a
circumferential step 116. In one embodiment, the inner peripheral
region 114 can be viewed as a width 120 of a ledge extended from
the step 116 circumferentially. Of course, the width 120 can vary
along the periphery though in most portions of the inner peripheral
region it can be made substantially equal to a same value for
simpler process or lower cost.
[0030] In another embodiment, the step 116 (visible as a loop line
in the top view) circumferentially can be characterized by one or
more athwart dimensions in one or more orientations, for example,
athwart lengths 121, 122, 123, and 124 as shown in FIG. 1A from one
side the step 116 across the frame structure to the opposing side
of the step 116. Depending on the shape defined by the step 116, a
single critical length can characterize a circle; two critical
lengths in two or more orientations can characterize a square;
three critical lengths in three or more orientations can
characterize a rectangle; etc. Of course, there can be many
alternatives, variations, and modifications.
[0031] Another frame structure 160 shown in top part of the FIG. 1A
is substantially similar to the frame structure 110 in shape and
characteristic dimensions. As shown, the frame structure 160
reveals another surface in closed loop including an outer
peripheral region 162 and an inner peripheral region 164 separated
by another circumferential step 166. FIG. 1A also shows that two
hinges 130 couple the frame structure 110 and frame structure 160
at the respective edges of the outer peripheral region 112 and the
opposing outer peripheral region 162. In addition, FIG. 1A also
shows a locking mechanism which may include two parts, one lock
part 150a being coupled to the frame structure 160 and another
mating lock part 150b being coupled to the frame structure 110.
More detail features of the carrier apparatus 100 can be found
throughout the specification and specifically below.
[0032] One structural features of the carrier apparatus 100 can be
further illustrated by cross sectional views. FIG. 1B shows an AA'
cross sectional view of a top frame structure 160 and a BB' cross
sectional view of a bottom frame structure 110 cutting along the
directions marked in FIG. 1A. This diagram is merely an example,
which should not unduly limit the scope of the claims herein. One
of ordinary skill in the art would recognize many variations,
alternatives, and modifications. As shown, the surface of the top
frame structure 160 revealed in FIG. 1A includes the outer
peripheral region 162 and the inner peripheral region 164 and both
face up in FIG. 1B and are separated by an up-step (i.e. the step
166) from the region 162 to region 164. Similarly shown, the
surface of the bottom frame structure 110 revealed in FIG. 1A
includes the outer peripheral region 112 and the inner peripheral
region 114 and both face up and are separated by an down-step
(i.e., the step 116) from region 112 to region 114. Also clearly
shown is the width 120 of the inner peripheral region 114.
[0033] In one embodiment, in terms of the cross sectional view, the
lateral dimensions (including 120) of inner peripheral regions 114
and 164 are configured to be properly mated with each other. For
example, the width 120 is substantially equal to or slightly bigger
than the corresponding width of the inner peripheral region 164. As
shown in the bottom part of FIG. 1B, the top frame structure 160 is
able to be flipped to engage with bottom frame structure 110. In
another embodiment, the step 116 is predetermined to be bigger than
the step 166 in step height so that a gap can be seen after the two
frame structures are fully engaged. The gap spacing 140 is
predetermined to adapt to a (standard) thickness of the sheet
material or thin wafer to be handled. For example, a thickness of
the silicon sheet material produced by cleaving a bulk
single-crystalline or polycrystalline silicon material for solar
cell application can be ranging from 10 to 200 microns. The gap
spacing 140, i.e., the difference between step 116 and step 166,
can be selected as 10 to 200 microns plus a positive margin of
about 5% to 10% of the thickness. In yet another embodiment, the
step up or down direction associated with step 166 or step 116 also
provides advantages for securing the shaped sheet material to be
held and stabilizing the mutual engagement between the two frame
structures (110 and 160). In yet still another embodiment, the step
edges of the inner peripheral regions 114 and 164 can be rounded to
reduce the surface damage to the sheet material being held.
[0034] In another embodiment, in terms of the two dimensional view,
the shape of step 166 characterized by one or more athwart
dimensions shall be configured to match with the shape of the step
116 circumferentially. In certain embodiments, the shape defined by
the step 116 and associated one or more athwart dimensions are
configured to adapt the corresponding shape and lateral dimensions
of sample material that is to be held by this apparatus. For
example, a thin wafer of silicon shall bear the same shape of the
bulk ingot material which may have been pre-shaped into a cylinder
with substantially square shape cross section with rounded corner
edges. Therefore, the shape of the inner peripheral region 114 in
terms of the step 116 will be configured to match at least the
straight edge portions and may leave extra room for corners.
Embodiments of the present invention have no restriction on exact
shapes that the step 116 can define, though one preferred
application is for handling the thin silicon sheets or wafers used
for photovoltaic cells that has a substantially square shape (with
truncated or rounded corners) with side-to-side dimension of about
100 millimeters, or about 125 millimeters, or about 156
millimeters. Of course, other embodiments of the present invention
can be applied to a much broader fields for handling various types
of shaped sheet materials.
[0035] FIG. 1C is a schematic diagram of a top view of the carrier
apparatus in FIG. 1A loaded with a shaped sheet material into the
bottom frame section according to an embodiment of the present
invention. This diagram is merely an example, which should not
unduly limit the scope of the claims herein. One of ordinary skill
in the art would recognize many variations, alternatives, and
modifications. As shown, the shaped sheet material 180
characterized by one or more lateral dimensions 121a through 124a
and a thickness (not visible by this top view diagram) is loaded
into the inner peripheral region 114 of the frame structure 110.
For example, the shaped sheet material 180 may be a thin silicon
wafer produced by cleaving a bulk single-crystalline or
polycrystalline silicon material for solar cell application. In
another example, the shaped sheet material 180 can be made of
germanium, or III/V group compound semiconductor for other
applications. Of course, there can be many alternatives,
variations, and modifications.
[0036] FIG. 1C is an exemplary illustration that the carrier
apparatus 100 has been configured to adapt the shape and dimension
of the inner peripheral region of the bottom frame structure to the
shaped sheet material 180. Specifically, the one or more athwart
dimensions 121 through 124 are correspondingly adapted to the one
or more lateral dimensions 121a through 124a. Furthermore, the
width 120 of the inner peripheral region 114, i.e., the width
between the step 116 and the edge of the inner peripheral region
(indicated by a dashed line in FIG. 1C) in certain orientation is
about 5% of the athwart dimension in that orientation of the
circumferential step 116. In one embodiment, the width 120 is
configured to support at least one or more peripheral portion of
the shaped sheet material 180.
[0037] Ideally the inner peripheral region 114 can be adapted to
support full peripheral portion of the shaped sheet material, but
practically, only partial portions of the periphery need to be
supported, depending on particular shape of the sheet material. As
shown in FIG. 1 C, the shaped sheet material 180 is a substantially
square shape with truncated or rounded corners. For example, the
shaped sheet material 180 is a thin silicon wafer of 100
millimeters and greater in lateral dimension produced by a layer
transfer technique based on RFQ linear accelerator system and used
for a variety of applications including photovoltaic cells.
Therefore, the four major side edges of the shaped sheet material
have been properly enclosed within the step 116 and been supported
by the inner peripheral region 114. For example, the width of the
inner peripheral region for supporting the major side edges is
about 5 mm or greater for an 100 mm-sized thin wafer. Of course,
there can be many alternatives, variations, and modifications. For
example, the corners of the inner peripheral region can have
extended spacing beyond the actual corner of the thin wafer. In
another example, the width of inner peripheral region near the
corners can be much smaller to reduce some contact area without
affecting stability of the thin wafer being held in the carrier
apparatus. In yet another example, around extended area of corners
the widths of inner peripheral region can be wider while the widths
around major side edge correspondingly are reduced to some extent
without affecting stability of the thin wafer being held in the
carrier apparatus.
[0038] FIG. 1D is a schematic diagram of a top view of the carrier
apparatus in a close position with loaded shaped sheet material
according to an embodiment of the present invention, and a HH'
cross sectional view is also shown. According to one embodiment as
shown in the top view, the top frame structure 160 is flipped to
allow the revealed surface of frame structure 160 in FIG. 1A to be
engaged with the revealed surface of frame structure 110 in FIG.
1A. Therefore, the frame structure 160 now completely covers frame
structure 110 as well as the peripheral portion of the shaped sheet
material 180. Schematically shown as an example, the shaped sheet
material 180 is fully enclosed within the step 166. In this close
position, lock part 150a on frame structure 160 correspondingly
engages with mating lock part 150b on frame structure 110 to become
a full lock 150 as shown in FIG. 1D. According to an embodiment as
shown in the HH' cross sectional view, the frame structure 160 is
capable to fully engage with the frame structure 110 holding a
shaped sheet material 180 of a thickness 185 in between the gap
spacing 140. This diagram is merely an example, which should not
unduly limit the scope of the claims herein. One of ordinary skill
in the art would recognize many variations, alternatives, and
modifications.
[0039] In one embodiment, the carrier apparatus 100 can be made by
various materials depending on applications. For example, the
carrier apparatus can be made by Teflon, PVDF (Polyvinylidene
Difluoride), PEEK (Polyetheretherketones), PET (polyethylene
terephthalate), polyimide, or other plastic materials using molds.
In some cases, other engaging and fixing mechanisms may be applied
to replace the hinges or locks. For example, flat head screws may
be used to mount two frame structures together without extra hinges
or handles so that the carrier apparatus can be easily fit into a
cassette allowing groups of thin wafer to be transferred from one
process to the other process during wafers process. In another
example, the carrier apparatus can be made by Quartz, ceramic or
glass material for the convenience of performing certain chemical
processes. In yet another example, the carrier apparatus can also
be made of metal including, but not limit to, aluminum, molybdenum,
anodized aluminum, stainless steel, or metal alloys. For example,
transition metal alloy containing elements of nickel, molybdenum,
chromium, cobalt, iron, copper, manganese, titanium, zirconium,
aluminum, carbon, and tungsten can be used for providing highly
corrosion resistant characteristics which is useful for performing
many chemical treatments to the shaped sheet material held by the
carrier apparatus. One example of such transition metal alloy is
Hastelloy.TM. made by Haynes International, Inc. Of course, there
can be many alternatives, variations, and modifications.
[0040] FIG. 1E is a schematic diagram of a carrier apparatus with a
cover circumferentially coupled to each frame structure according
to another embodiment of the present invention. This diagram is
merely an example, which should not unduly limit the scope of the
claims herein. One of ordinary skill in the art would recognize
many variations, alternatives, and modifications. In one
embodiment, the carrier apparatus 100a can be substantially the
same as the carrier apparatus 100 shown in FIGS. 1A-1D except that
the carrier apparatus 100a has an additional cover on each frame
structure. In particular, as shown in FIG. 1E, the cover 170
integrally and circumferentially couples to the edge of the inner
peripheral region. In one embodiment, the cover 170 can be made the
same material as that for the rest parts of the carrier apparatus.
In another embodiment, depending on applications, the cover 170 can
be made from a material different from that for the rest parts of
the carrier apparatus. The carrier apparatus 100a with cover 170 on
each frame usually is preferred for the application of storage and
shipping.
[0041] FIG. 2 is a simplified flowchart showing a method for
handling a shaped sheet material according to an alternative
embodiment of the present invention. This diagram is merely an
example, particularly using a carrier apparatus with a first frame
structure and a second frame structure coupled by one or more
hinges, which should not unduly limit the scope of the claimed
herein. For example, various processes may be added, removed,
replaced, repeated, overlapped, and/or partially overlapped. The
method 200 includes the following processes:
[0042] 1. Process 210 for providing a shaped sheet material;
[0043] 2. Process 212 for providing a carrier apparatus including a
first frame structure and a second frame structure;
[0044] 3. Process 214 for exposing the first frame structure;
[0045] 4. Process 216 for loading the shaped sheet material onto
the first frame structure;
[0046] 5. Process 218 for engaging the second frame structure with
the first frame structure to close the carrier apparatus holding
the shaped sheet material;
[0047] 6. Process 220 for transferring the carrier apparatus to
process the shaped sheet material held therein.
[0048] The above sequence of processes provides a method according
to an embodiment of the present invention. Other alternatives can
also be provided where processes are added, one or more processes
are removed, or one or more processes are provided in a different
sequence without departing from the scope of the claims herein.
Alternate carrier apparatus may be used. For example, the second
frame structure is added to engage with the first frame structure
loaded with the shaped sheet material, then mounted by flat head
screws. Future details of the present invention can be found
throughout the present specification and more particularly
below.
[0049] At Process 210, the method 200 includes a step to provide a
shaped sheet material. In particular, the shaped sheet material
includes, but not limited to, a thin wafer produced by cleaving a
bulk material including ingots of single-crystalline or
polycrystalline silicon, or germanium, or III/V group compound
semiconductor. For example, the cleaving process is based on a
thick layer transfer technique using ion implantation from high
energy ion beam generated by a linear accelerator. More detailed
descriptions about the thick layer transfer in association with
liner accelerator system can be found in a co-assigned U.S. patent
application Ser. No. 11/935,197 by Francois J Henley et al., and
titled "METHOD AND STRUCTURE FOR THICK LAYER TRANSFER USING A
LINEAR ACCELERATOR", filed on Nov. 5, 2007. Typically, the produced
thin wafer has a thickness in a range of 10 microns to 200 microns
depending on applications. For silicon thin wafer used for
photovoltaic cell application, the shape is primarily a square with
rounded corners. The width/length is about 100 millimeters, or
about 125 millimeters, or about 156 millimeters.
[0050] At Process 212, a carrier apparatus including a first frame
structure and a second frame structure is provided. In one example,
the carrier apparatus with just frame structure (100) is provided.
In another example, the carrier apparatus with covers (100a) is
provided. In yet another example, a carrier apparatus 300,
described in the specification below, can be provided. In yet still
another example, a carrier apparatus with a shaped wing structure
(400), described in specification below, can also be used.
According to certain embodiments of the present invention, process
for providing a carrier apparatus includes determining the first
frame structure that is adapted to the shaped sheet material. In
particular, the shape of the first frame structure at least
partially bear some analogy to the shaped sheet material. For
example, the first frame structure is the bottom frame structure
110 of the carrier apparatus 100 such that the first inner
peripheral region bounded by the step 116 is configured with one or
more characteristic athwart dimension and a width of ledge to
properly enclose and support the shaped sheet material 180. In
another embodiment, the height of the step 116 is also configured
to accommodate the thickness 185 of the shaped sheet material.
[0051] According to certain embodiments, the process for providing
a carrier apparatus further includes determining the second frame
structure. Basically, the second frame structure needs to be
configured to be fully engaged with the first frame structure in a
close position such that the shaped sheet material is held in
between. For example, the second frame structure is the top frame
structure 160. In particular, the inner peripheral region 164
associated with the top frame structure is disposed opposing to the
inner peripheral region 114 of the bottom frame structure as the
step 166 mates with the step 116. The height of step 166 is
determined to provide a gap between the two inner peripheral
regions 164 and 114 in the close position, which is large enough
for accommodate the thickness of the shaped sheet material
therein.
[0052] At Process 214, the method 200 including exposing the first
frame structure. In one embodiment, the second frame structure is
coupled to the first frame structure by one or more hinges so that
the second frame structure can be flipped open by rotating the
second frame structure against the one or more hinges. In one
example, the hinges are capable of rotating about 180 degrees so
that the first frame structure may be fully exposed. In another
example, the second frame structure is flipped open to certain
degrees just large enough for a shaped sheet material to be loaded
successfully into the first frame structure. In an alternative
embodiment, a second frame structure is not coupled to the first
frame structure by hinge and can be simply removed away to allow
the first frame structure exposed and ready for loading the shaped
sheet material or thin wafer. Of course, there can be many
alternatives, variations, and modifications. Alternative design of
carrier apparatus and the method of use can be found in later part
of the specification.
[0053] At Process 216, the shaped sheet material is loaded onto the
first frame structure. In one example, the shaped sheet material is
a thin wafer cleaved from a bulk material with a thickness in a
range of 10 to 200 microns. The state-of-art techniques for
handling such thin wafer includes using of electrostatic chuck or
vacuum chuck. For example, a robot with an electrostatic chuck
plate may be used. As the chuck plate is disposed to a proximity
position of the thin wafer, a chuck voltage with a predetermined
polarity and value can be applied to the chuck plate to generate an
attractive electrostatic force to suck the thin wafer to the plate.
Then it can be transferred by the robot toward the right position
as planned. As the shaped sheet material or thin wafer is fully
enclosed within the step 116 associated with the inner peripheral
region of the first frame structure. A predetermined dechucking
voltage can be applied to clear the electrostatic force so that the
shaped sheet material can freely rest on the inner peripheral
region, and the robot can be retracted. Of course, there can be
many alternatives, variations, and modifications.
[0054] At Process 218, the method 200 includes engaging the second
frame structure with the first frame structure to close the carrier
apparatus holding the shaped sheet material. In one embodiment, the
second frame structure is coupled to the first frame structure by
one or more hinges so that the second frame structure can be
flipped close by rotating the second frame structure against the
one or more hinges. In another embodiment, the (separated) second
frame structure is directly disposed on top the first frame
structure with the corresponding surfaces engaged each other so
that the loaded shaped sheet material is enclosed therein.
Subsequently, a locking mechanism may be applied to secure the
engagement. The locking mechanism includes one or more clips, or
one or more screws, or one or more springs, or one or more latches.
For example, after two separated frame structures engage each
other, one or more flat head screws can be applied to one or more
predrilled holes (threaded hole or through-hole with stop region)
near the corners of the frame structures to completely tied them
together, thereby securing the shaped sheet material held therein.
Of course, there can be many alternatives, variations, and
modifications.
[0055] At Process 220, the carrier apparatus can be transferred to
one or more process stations to process the shaped sheet material
held therein. In one embodiment, the carrier apparatus is
individually transferred. In another embodiment, multiple carrier
apparatuses can be loaded into a cassette or wafer boat which has
been configured to include multiple slots each designed for
vertically holding one carrier apparatus. For example, for
convenience of holding the carrier apparatus into the slot, the
carrier apparatus with a locking mechanism using one or more flat
head screws can be used. In another example, the carrier apparatus
with a shaped wing structure extended from outer peripheral edge
can be used. The shaped wing structure can be configured to have
certain diameter and thickness to fit in each slot of the standard
cassette or wafer boat. The slot-to-slot spacing has been adapted
to a total thickness of the carrier apparatus so that one carrier
apparatus loaded in one slot has clearance spacing from another
carrier apparatus loaded in a neighboring slot. Of course, the
cassette or wafer boat can be adapted for various variations of the
carrier apparatus structure.
[0056] After loaded with multiple carrier apparatuses, the cassette
can then be transferred to one or more process stations to allow a
group of shaped sheet material to be processed. Note each carrier
apparatus is characterized by a frame structure or engaged frame
structures. Therefore the major portions of two surfaces of the
shaped sheet material are exposed and then can be processed
simultaneously within the process station. The process involved
includes, but not limited to, standard wet-bench cleaning, chemical
etching, deposition, thermal annealing, and certain material
characterization. In an alternative embodiment, the carrier
apparatus can include a cover coupled to each frame structure so
that the surfaces of the shaped sheet material do not expose
directly. In addition, the carrier apparatus can include hinges to
couple the two frame structures and clip locking mechanism. These
types of carrier apparatuses may be handled individually and
preferred for storage, shipping and other wafer transfer
applications requiring to keep the surfaces from being contaminated
or dusted. Of course, there can be many alternatives, variations,
and modifications. More details about alternative carrier apparatus
structures and cassette design can be found in specification
below.
[0057] FIG. 3A is an exemplary top view of an alternative carrier
apparatus with two frame members at an open position for a shaped
sheet material according to another embodiment of the present
invention. This diagram is merely an example, which should not
unduly limit the scope of the claims herein. One of ordinary skill
in the art would recognize many variations, alternatives, and
modifications. As shown, the carrier apparatus 300 includes two
C-like frame members 310 and 360. The frame member 310 includes a
middle section 315 and two arm sections 317a and 317b each extended
integrally from two ends of the middle section 315 to form a C-like
shape. The C-like frame member 310 naturally includes an inner
surface 316 and an outer surface 318, shown just lines in the top
view section of FIG. 3A. In one embodiment, the curvature and
dimensions associated with the middle section 315 and/or two arm
section can be determined to adapt the shaped sheet material. For
example, the shaped sheet material can be substantially a square
with four rounded or truncated corners.
[0058] As shown in FIG. 3A, the two arm sections include some
unique structural features. Firstly, in one example, the two arm
sections 317a and 317b can be substantially the same in terms of a
length, width, and some relevant structure details. Secondly, each
arm section includes two side ridges, side ridge 311a for arm
section 317a, or side ridge 311b for arm section 317b, integrally
coupled to rest of the corresponding arm section with half the arm
length starting from the end. In between the two side ridges, it is
an open slot 312 which extends also from the end of arm section and
further deep into the arm section by another half arm length,
forming a hole 313a for arm section 317a or a hole 313b for arm
section 317b. Referring to the FIG. 3A, the top view reveals the
shape of the side ridges, the open slot, and the hole all are in
rectangular shape. Of course, there can be many alternatives,
variations, and modifications.
[0059] In one embodiment, another frame member 360 has a
substantially similar structure as the frame member 3 10. In
particular, the frame member 360 includes a middle section 365 and
two arm sections 367a and 367b each integrally extended from the
two ends of the middle section 365 to form a C-like shape. The
C-like frame member 360 includes an inner surface 366 and an outer
surface 368. In another embodiment, the two arm sections 367a and
367b may be substantially redundant or different depending on the
shape of the sheet material to be loaded. In yet another
embodiment, the arm section 367a includes a rod 363a with a half
arm length starting from the end of the arm section and similarly
the arm section 367b has a rod 363b. The arm section 367a further
includes two side slots 316a disposed from the location of half arm
length to extend another half arm length along the arm section.
Similarly the arm section 367b includes two side slots 361b. In a
specific embodiment, the rod 363a/363b is configured to be slid
into the open slot 312a/312b and further be engaged with the hole
311a/311b at a close position, thereby forming a complete closed
loop frame for holding the shaped sheet material therein. The arm
sections with sliding rod/slot structure also serves a locking
mechanism. Of course, there can be many alternatives, variations,
and modifications.
[0060] A YY' cross sectional view is illustrated at the lower part
of FIG. 3A, showing the inner surface 316 or 366 and outer surface
318 or 368. It is seen that the inner surface 316 or 366 has a
cut-in slot 320 or slot 370 with a predetermined depth 321 or depth
371 respectively. The slot is configured to receive the shaped
sheet material. For the convenience of insert the sheet material
the opening of the slot near the inner surface is relatively wider
and the width gradually is reduced to a certain value towards the
bottom of the slot. In one embodiment, the minimum width of the
slot shall accommodate a thickness of the shaped sheet material to
be inserted. Referring to the top view part of FIG. 3A, the middle
dashed line represents the bottom line of the slot along the whole
inner surface for both frame member 310 and frame member 360. When
the frame member 360 is engaged with the frame member 310, the
cut-in slot 320 and slot 370 merges together. In addition, the
inner surface has been adapted to the shaped sheet material so that
the combined cut-in slot 320 plus slot 370 can be used to hold the
shaped sheet material circumferentially. In a specific embodiment,
the cut-in slot near the arm section can be offset from those side
ridges or side slot to avoid interference.
[0061] In one embodiment, the carrier apparatus 300 can be made by
various materials depending on applications. For example, the
carrier apparatus can be made by Teflon, PVDF (Polyvinylidene
Difluoride), PEEK (Polyetheretherketones), PET (polyethylene
terephthalate), polyimide, or other plastic materials using molds.
In some cases, other engaging and fixing mechanisms may be applied
to replace the hinges or locks. For example, flat head screws may
be used to mount two frame structures together without extra hinges
or handles so that the carrier apparatus can be easily fit into a
cassette allowing groups of thin wafer to be transferred from one
process to the other process during wafers process. In another
example, the carrier apparatus can be made by Quartz, ceramic or
glass material for the convenience of performing certain chemical
processes. In yet another example, the carrier apparatus can also
be made of metal including, but not limit to, aluminum, molybdenum,
anodized aluminum, stainless steel, or metal alloys. For example,
transition metal alloy containing elements of nickel, molybdenum,
chromium, cobalt, iron, copper, manganese, titanium, zirconium,
aluminum, carbon, and tungsten can be used for providing highly
corrosion resistant characteristics which is useful for performing
many chemical treatments to the shaped sheet material held by the
carrier apparatus. One example of such transition metal alloy is
Hastelloy.TM. made by Haynes International, Inc. Of course, there
can be many alternatives, variations, and modifications.
[0062] One possible method of use associated with the carrier
apparatus 300 can go through the following processes: firstly,
remove one of the two C-like frame members; secondly, load in the
shaped sheet material into the slot of remaining C-like frame
member; thirdly, re-install the C-like frame member removed earlier
by carefully sliding the rod into the open slot and hole for
corresponding arm sections till a close position; and complete
locking mechanism at the close position. FIG. 3B just shows an
exemplary top view of the carrier apparatus in FIG. 3A at the close
position according to an embodiment of the present invention. FIG.
3C is an exemplary top view of the carrier apparatus in FIGS. 3A
and 3B at the close position with a shaped sheet material being
held therein according to an embodiment of the present invention.
These diagrams are merely examples, which should not unduly limit
the scope of the claims herein. One of ordinary skill in the art
would recognize many variations, alternatives, and
modifications.
[0063] FIG. 4 is a simplified diagram showing a carrier apparatus
with a top view of a first frame structure having an extended wing
structure and a mating second frame structure for holding a shaped
sheet material according to an embodiment of the present invention.
This diagram is merely an example, which should not unduly limit
the scope of the claims herein. One of ordinary skill in the art
would recognize many variations, alternatives, and modifications.
As shown, a carrier apparatus 400 includes a first frame structure
410 and a second frame structure 460. The first frame structure 410
has a first front surface (visible in this top view) including a
first outer peripheral region 412 and a first inner peripheral
region 414 separated by a first step 416. The shape and dimensions
of the first inner peripheral region are configured to be
substantially similar to a shaped sheet material to be loaded. In
one embodiment, through not being directly viewable in top view,
the first inner peripheral region 414 can be positioned lower than
the first outer peripheral region 412 by the step height of the
first step 416 so that the shaped sheet material can be loaded in
and supported by the first inner peripheral region and
circumferentially confined within the first step 416. In a specific
embodiment, the first frame structure without the wing structure is
substantially the same the frame structure 110 (excepting the
handle or hinges) as seen earlier in FIG. 1A.
[0064] As shown in FIG. 4, the first frame structure 410 includes a
shaped wing structure 470 that is integrally extended from outer
peripheral edge 422 of the first frame structure 410. The shaped
wing structure is characterized by a shape with a lateral dimension
and a thickness. The shape has no specific limit in general but its
lateral dimension and the thickness are adapted to fit in a
cassette or wafer boat that can hold the carrier apparatus. For
example, the shaped wing structure can be made into a round
peripheral shape as seen in FIG. 4 for the convenience of
manufacture and handling. The diameter and thickness of the round
shaped wing structure can be adapted to certain standard cassette
or wafer boat. In one example, the diameter of the round wing
structure can be about 4 to 12 inches depending on the frame
structures required for holding certain sized shaped sheet
material. The thickness of the wing structure can be about 1 mm or
less. In other examples, the shaped wing structure can be an oval
or a polygon with one or more lateral dimensions and a thickness
fitting the corresponding cassette or wafer boat. Of course, there
can be many alternatives, variations, and modifications.
[0065] In another embodiment, as shown in FIG. 4, the second frame
structure 460 is configured to have substantially the same frame
shape and lateral dimension as the first frame structure 410 so
that both of them can be coupled together as a complete carrier
apparatus 400. As shown in this top view diagram, the second frame
structure 460 has a second front surface including a second outer
peripheral region 462 and a second inner peripheral region 464
separated by a second step 466. Again, though not directly viewable
in the top view, in one embodiment the second inner peripheral
region 464 is made to be extruded above the second outer peripheral
region 462 by the step height of the second step 466. In a specific
embodiment, the second step 466 is configured to be substantially
similar to the first step with slightly smaller lateral dimension
and smaller step height. Therefore, the second frame structure 460
can be flipped over so that the second front surface is able to
mate with the first front surface. In particular, the second step
just fits within the first step circumferentially. In another
specific embodiment, the difference in step height between the
first step 416 and the second step 466 provides a space between the
first inner peripheral region 414 and the second inner peripheral
region 464 which is adapted for holding a shaped sheet material
therein. In one example, the second frame structure 460 is
substantially the same as the frame structure 160 (excepting any
coupling mechanism).
[0066] In yet another embodiment, the carrier apparatus includes a
locking mechanism associated with both the first frame structure
410 and the second frame structure 460 so that the two separate
mechanical pieces can be securely coupled together. In particular,
as shown in FIG. 4, the first frame structure 410 includes a first
plurality of holes 450a disposed near corner areas of the first
frame structure and the second frame structure includes a second
plurality of holes 450b disposed near corresponding corner areas of
the second frame structure. The holes 450a and 450b are
substantially one-to-one matched in position when the second frame
structure 460 engages with the first frame structure 460. In one
embodiment, these holes can be threaded holes or through-holes with
a stop region so that flat head screws (not shown) can be utilized
for coupling both frame structures and securing the held shaped
sheet material. This type of locking mechanism has no extruded
structure around frame periphery providing convenience for being
fitted into the cassette and being handled in group. Of course,
other types of locking mechanisms can be used. One of skilled in
the art should recognize many alternatives, variations, and
modifications. For example, one or more hinges plus clips, one or
more springs plus hooks, one or more latches plus stoppers, can be
used.
[0067] In one embodiment, the carrier apparatus 400 can be made by
various materials depending on applications. For example, the
carrier apparatus can be made by Teflon, PVDF (Polyvinylidene
Difluoride), PEEK (Polyetheretherketones), PET (polyethylene
terephthalate), polyimide, or other plastic materials using molds.
In some cases, other engaging and fixing mechanisms may be applied
to replace the hinges or locks. For example, flat head screws may
be used to mount two frame structures together without extra hinges
or handles so that the carrier apparatus can be easily fit into a
cassette allowing groups of thin wafer to be transferred from one
process to the other process during wafers process. In another
example, the carrier apparatus can be made by Quartz, ceramic or
glass material for the convenience of performing certain chemical
processes. In yet another example, the carrier apparatus can also
be made of metal including, but not limit to, aluminum, molybdenum,
anodized aluminum, stainless steel, or metal alloys. For example,
transition metal alloy containing elements of nickel, molybdenum,
chromium, cobalt, iron, copper, manganese, titanium, zirconium,
aluminum, carbon, and tungsten can be used for providing highly
corrosion resistant characteristics which is useful for performing
many chemical treatments to the shaped sheet material held by the
carrier apparatus. One example of such transition metal alloy is
Hastelloy.TM. made by Haynes International, Inc. Of course, there
can be many alternatives, variations, and modifications.
[0068] FIG. 5A is a prospect view of a carrier cassette with a
plurality of matched slots each configured to hold a carrier
apparatus according to an alternative embodiment of the present
invention. This diagram is merely an example, which should not
unduly limit the scope of the claims herein. One of ordinary skill
in the art would recognize many variations, alternatives, and
modifications. As shown, the carrier cassette 500 includes a length
530 of a bulk structure with a U-like cross section including a
bottom surface 520 and an inner surface 510. The inner surface 510
includes a plurality of slots 512n, where n can be an integer
greater than 10, or greater than 15, or greater than 20. disposed
perpendicular to the length of the bulk structure with a
predetermined spacing 540 between each other. Each of the plurality
of slots 512n is configured to be engaged by a carrier apparatus.
For example, the carrier apparatus is the carrier apparatus 400. In
another example, the carrier apparatus is the carrier apparatus
300.
[0069] In one embodiment, the U-like cross section of the bulk
structure has a base width 560 which also defines the cross spacing
of the plurality of slots 5 12n built-in within the inner surface
510. This width 560 is adapted to the lateral dimensions of the
carrier apparatus to be loaded. For example, the shape of the
U-like cross section, particularly the bottom section, is adapted
to the frame structure with the shaped wing structure 470 of the
carrier apparatus 400 shown in FIG. 4. In another embodiment, the
U-like cross section also is characterized by a height 550 from the
middle part of inner surface 510 to an upper edge of the U-like
section. The height 550 is preferred to be greater than half the
size of lateral dimension of the carrier apparatus so that the
loaded carrier apparatus will be stable and secured within the
cassette. Of course, there can be many alternatives, variations,
and modifications.
[0070] In another embodiment, each slot 512n is associated with a
width 540 and an inter-slot spacing 545. The width 540 is designed
to hold one carrier apparatus therein. For example, the width 540
is about 1 mm which is able to receive the thickness of the shaped
wing structure 470 so that the carrier apparatus can be inserted
into the slot 512n. The inter-slot spacing 545 is also adapted to a
total thickness of the carrier apparatus so that a carrier
apparatus loaded in one slot (for example 512.sub.1) has a
clearance space from another carrier apparatus loaded in a
neighboring slot (for example 512.sub.2). For example, the total
thickness of the carrier apparatus includes the thickness of both
the first frame structure 410 and the second frame structure 460.
Depending on the applications, some carrier cassette may need wider
spacing between each slot based on consideration of processing
conditions. Other carrier cassette can make the spacing tighter to
hold as many carrier apparatus as it can. In a specific embodiment,
the carrier cassette may further include one ore more handles (not
shown) coupled with two upper edges or side edges of the U-like
shaped bulk structure for convenience of cassette transporting or
loading in/out the processing station. In another specific
embodiment, the bottom part of each slot 512n can have one or more
through holes 518n that allow top-down venting/convection based on
certain considerations of chemical or thermal processing
conditions. Of course, one of ordinary skill in the art would
recognize many variations, alternatives, and modifications in those
detail features under the scope of the claims herein.
[0071] FIG. 5B is a prospect view of the carrier cassette in FIG.
5A holding two carrier apparatuses each holding a shaped sheet
material therein according to an embodiment of the present
invention. This diagram is merely an example, which should not
unduly limit the scope of the claims herein. One of ordinary skill
in the art would recognize many variations, alternatives, and
modifications. As shown, one of the carrier cassette 500 is loaded
with two carrier apparatus 400.sub.n and 400.sub.n+1. Each carrier
apparatus sits in one slot 512n. For example, each of the carrier
apparatus 400.sub.n and 400.sub.n+1 can be one of the carrier
apparatus 400 shown in FIG. 4. Each carrier apparatus is holding a
shaped sheet material therein. In one example, the shaped sheet
material is a deformable thin wafer. In particular, the shaped
sheet material is a silicon thin wafer of 10-200 .mu.m in thickness
and about 50 mm, or 100 mm, or 125 mm, or 156 mm in lateral
dimension produced by cleaving a bulk ingot of single-crystalline
or polycrystalline silicon based on thick layer transfer technique
using linear accelerator ion implantation. With this set up, every
surface of each shaped sheet material held in each carrier
apparatus within the groups loaded in the cassette can be processed
at the same time efficiently.
[0072] Having described several embodiments, it will be recognized
by those of skill in the art that various modifications,
alternative constructions, and equivalents may be used without
departing from the spirit of the invention. Additionally, a number
of well known processes and elements have not been described in
order to avoid unnecessarily obscuring the present invention.
Accordingly, the above description should not be taken as limiting
the scope of the invention.
[0073] Where a range of values is provided, it is understood that
each intervening value, to the tenth of the unit of the lower limit
unless the context clearly dictates otherwise, between the upper
and lower limits of that range is also specifically disclosed. Each
smaller range between any stated value or intervening value in a
stated range and any other stated or intervening value in that
stated range is encompassed. The upper and lower limits of these
smaller ranges may independently be included or excluded in the
range, and each range where either, neither or both limits are
included in the smaller ranges is also encompassed within the
invention, subject to any specifically excluded limit in the stated
range. Where the stated range includes one or both of the limits,
ranges excluding either or both of those included limits are also
included.
[0074] It is also understood that the examples and embodiments
described herein are for illustrative purposes only and that
various modifications or changes in light thereof will be suggested
to persons skilled in the art and are to be included within the
spirit and purview of this application and scope of the applied
claims.
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