U.S. patent application number 15/338969 was filed with the patent office on 2017-10-19 for thin film battery device and method of formation.
The applicant listed for this patent is Applied Materials, Inc.. Invention is credited to Dimitrios Argyris, Jeffrey L. Franklin, Byung-Sung Kwak, Giback Park, Lizhong Sun, Michael Yu-Tak Young.
Application Number | 20170301954 15/338969 |
Document ID | / |
Family ID | 60038434 |
Filed Date | 2017-10-19 |
United States Patent
Application |
20170301954 |
Kind Code |
A1 |
Kwak; Byung-Sung ; et
al. |
October 19, 2017 |
THIN FILM BATTERY DEVICE AND METHOD OF FORMATION
Abstract
A thin film battery may include: a cathode current collector,
the cathode current collector being disposed in a first plane; a
device stack disposed on the cathode current collector, the device
stack comprising an anode current collector, the anode current
collector being disposed in a second plane, above the first plane;
and a thin film encapsulant, the thin film encapsulant disposed
above the device stack, wherein the thin film encapsulant comprises
a first portion extending along a surface of the anode current
collector and a second portion extending along a plurality of sides
of the device stack, wherein the cathode current collector extends
under the second portion of the thin film encapsulant and outside
of the thin film encapsulant; and wherein the anode current
collector extends under the first portion of the thin film
encapsulant and outside of the thin film encapsulant.
Inventors: |
Kwak; Byung-Sung; (Portland,
OR) ; Sun; Lizhong; (San Jose, CA) ; Park;
Giback; (San Jose, CA) ; Argyris; Dimitrios;
(Los Altos, CA) ; Young; Michael Yu-Tak;
(Cupertino, CA) ; Franklin; Jeffrey L.;
(Albuquerque, NM) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Applied Materials, Inc. |
Santa Clara |
CA |
US |
|
|
Family ID: |
60038434 |
Appl. No.: |
15/338969 |
Filed: |
October 31, 2016 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62322415 |
Apr 14, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 4/382 20130101;
H01M 10/0436 20130101; B23K 26/362 20130101; H01M 2/0287 20130101;
H01M 2/08 20130101; B23K 26/142 20151001; H01M 2/026 20130101; B23K
2101/34 20180801; H01M 2/0267 20130101; H01J 37/32715 20130101;
H01M 10/052 20130101; H01M 6/18 20130101; B23K 2103/172 20180801;
H01M 2/0207 20130101; H01M 6/40 20130101; H01M 10/0585 20130101;
H01M 2300/0068 20130101; B23K 26/0006 20130101; H01M 2/1094
20130101; B23K 2101/36 20180801; C23C 14/50 20130101; H01M 6/005
20130101; Y02E 60/10 20130101; H01M 2220/30 20130101; H01M
2300/0065 20130101; H01J 37/3426 20130101; H01M 4/525 20130101;
H01M 6/188 20130101; H01M 10/0525 20130101; C23C 14/34 20130101;
B29C 59/16 20130101; Y02T 10/70 20130101; B29K 2995/0006 20130101;
B29L 2031/3468 20130101 |
International
Class: |
H01M 10/0585 20100101
H01M010/0585; H01M 2/08 20060101 H01M002/08; H01M 2/02 20060101
H01M002/02; H01M 10/04 20060101 H01M010/04; H01M 10/0525 20100101
H01M010/0525 |
Claims
1. A thin film battery, comprising: a cathode current collector,
the cathode current collector being disposed in a first plane; a
device stack disposed on the cathode current collector, the device
stack comprising an anode current collector, the anode current
collector being disposed in a second plane, above the first plane;
and a thin film encapsulant, the thin film encapsulant disposed
above the device stack, wherein the thin film encapsulant comprises
a first portion extending along a surface of the anode current
collector and a second portion extending along a plurality of sides
of the device stack, wherein the cathode current collector extends
under the second portion of the thin film encapsulant and outside
of the thin film encapsulant, and wherein the anode current
collector extends under the first portion of the thin film
encapsulant and outside of the thin film encapsulant.
2. The thin film battery of claim 1, wherein the thin film
encapsulant comprises at least one dyad, wherein a dyad of the at
least one dyad comprises: a soft and pliable polymer layer; and a
rigid dielectric layer or a rigid metal layer, the soft and pliable
polymer layer being disposed adjacent the rigid dielectric layer or
rigid metal layer.
3. The thin film battery of claim 1, wherein the device stack
further comprises: a cathode, the cathode being disposed on the
cathode current collector; and a solid state electrolyte, the solid
state electrolyte disposed on the cathode and under the anode
current collector.
4. The thin film battery of claim 3, wherein the thin film
encapsulant encapsulates the cathode, the solid state electrolyte
and the anode current collector on a side of the device stack.
5. The thin film battery of claim 4, wherein the thin film
encapsulant comprises a polymer layer and a rigid dielectric layer,
the rigid dielectric layer being disposed adjacent the polymer
layer, wherein the polymer layer and the rigid dielectric layer
extend in a non-planar fashion along the surface of the anode
current collector and along the side of the device stack.
6. The thin film battery of claim 2, wherein the thin film
encapsulant comprises a plurality of dyads, wherein the thin film
encapsulant further comprises a third region, wherein in the third
region, in at least one dyad of the plurality of dyads the soft and
pliable polymer layer and the rigid dielectric layer extend in a
non-planar fashion above the surface of the anode current
collector.
7. The thin film battery of claim 1 further comprising a substrate
base, the substrate base disposed adjacent the cathode current
collector.
8. A method of forming a thin film battery, comprising: depositing
a cathode current collector on a substrate in a first plane;
forming a device stack on the cathode current collector, the device
stack comprising an anode current collector, the anode current
collector being disposed in a second plane above the first plane;
and forming a thin film encapsulant above the device stack, wherein
the thin film encapsulant comprises a first portion extending along
a surface of the anode current collector and a second portion
extending along a side of the device stack, wherein the cathode
current collector extends under the device stack, under the second
portion of the thin film encapsulant and outside of the thin film
encapsulant, and wherein the anode current collector extends under
the first portion of the thin film encapsulant and outside of the
thin film encapsulant.
9. The method of claim 8, wherein the forming the device stack
comprises: depositing a cathode layer on the cathode current
collector; annealing the substrate after the depositing the cathode
layer; depositing a solid state electrolyte layer on the cathode
layer; depositing the anode current collector on the solid state
electrolyte layer; and before the forming the thin film
encapsulant, patterning the cathode layer, the solid state
electrolyte layer, and the anode current collector to form the
device stack and to expose the cathode current collector in a first
region.
10. The method of claim 9, further comprising depositing a lithium
anode layer after the depositing the solid state electrolyte layer
and before the depositing the anode current collector.
11. The method of claim 9, wherein the patterning the cathode
layer, the solid state electrolyte layer, and the anode current
collector comprises etching the cathode layer, the solid state
electrolyte layer, and the anode current collector over the first
region using laser ablation to selectively remove a portion of the
cathode layer, the solid state electrolyte layer, and the anode
current collector.
12. The method of claim 9, wherein the forming the thin film
encapsulant comprises forming a plurality of patterned dyads on the
anode current collector, wherein a given patterned dyad of the
plurality of patterned dyads comprises a soft and pliable polymer
layer and a rigid dielectric layer.
13. The method of claim 9, wherein the forming the thin film
encapsulant comprises: depositing a plurality of layers, wherein at
least one layer comprises a soft and pliable polymer and at least
one layer comprises a rigid dielectric layer; and etching the
plurality of layers using a plurality of etch operations.
14. The method of claim 9, wherein the forming the thin film
encapsulant comprises depositing an initial polymer layer in
blanket form directly on the anode current collector and on the
first region of the cathode current collector, wherein the initial
polymer layer comprises a soft and pliable polymer.
15. The method of claim 14, further comprising: after the
depositing the initial polymer layer: patterning the initial
polymer layer to form a patterned polymer layer over the device
stack and to expose the cathode current collector in a second
region, the second region being disposed in the first region.
16. The method of claim 15, further comprising performing, at least
once, a patterned dyad process me, the patterned dyad process
comprising: depositing a blanket dyad comprising a rigid dielectric
layer and a polymer layer on the device stack and on the cathode
current collector; and patterning the blanket dyad to form a
patterned thin film encapsulant over the device stack and to expose
the cathode current collector in a new region, the new region being
disposed in the second region.
17. The method of claim 16, further comprising: depositing a final
rigid dielectric layer in blanket form on the patterned thin film
encapsulant and on the new region of the cathode current collector;
and patterning the final rigid dielectric layer to form the thin
film encapsulant, the thin film encapsulant being disposed over the
device stack and exposing the cathode current collector in a new
region, the new region being disposed in the second region.
18. A method of encapsulating a thin film battery, comprising:
providing an active device region on a substrate base, wherein the
active device region comprises a cathode current collector and a
device stack, the device stack being disposed on a portion of the
cathode current collector and including an anode current collector;
and forming a thin film encapsulant above the device stack, wherein
the thin film encapsulant comprises a first portion extending along
a surface of the anode current collector and a second portion
extending along a side of the device stack, wherein the cathode
current collector extends under the device stack, under the second
portion of the thin film encapsulant and outside of the thin film
encapsulant, and wherein the anode current collector extends under
the first portion of the thin film encapsulant and outside of the
thin film encapsulant.
19. The method of claim 18, wherein the active device region
further comprises a cathode and a solid state electrolyte, wherein
the providing the active device region comprises: depositing in
blanket form the cathode current collector, the cathode, the solid
state electrolyte, and the anode current collector; and patterning
the anode current collector, the solid state electrolyte, and the
cathode, wherein a portion of the cathode current collector is
exposed.
Description
RELATED APPLICATIONS
[0001] This Application claims priority to U.S. provisional patent
application No. 62/322,415, filed Apr. 14, 2016, entitled "Volume
Change Accommodating TFE Materials," and incorporated by reference
herein in its entirety.
FIELD
[0002] The present embodiments relate to thin film encapsulation
(TFE) technology used to protect active devices, and more
particularly to encapsulating thin film battery devices.
BACKGROUND
[0003] In the fabrication of thin film batteries, patterning of
device structures remains a challenge, for forming active regions
of a device, or front-end, and for forming encapsulation portions
of a device, or back-end.
[0004] In particular, for seamless integration into systems
incorporating thin film batteries, a large benefit is the ability
to form very thin batteries. To this end, reduction of non-active
materials such as encapsulation material is useful, so non-active
portions of a thin film battery add minimally to the overall size
of the battery. Known methods of packaging energy storage devices,
such as thin film batteries, include pouching, lamination, and the
like. These methods add an undesirable amount of weight and volume
to the device being packaged, or encapsulated. Thin film
encapsulation (TFE) approaches for protecting active components of
a thin film battery offer a potentially simplified manner of
encapsulation, with minimum material and volume addition to the
system. Notably, TFE approaches for these types of devices, such as
thin film batteries, are far more challenging for several reasons.
Firstly, accommodation of volume changes is useful, adding
potential stress to a thin film encapsulant region during device
operation. Secondly, a main function of the TFE is to provide good
oxidant permeation barrier properties. Moreover, a TFE may be used
encapsulate device structures including a larger topography
variation. At the present, good TFE fabrication methods and the
resulting device architectures are lacking for providing robust and
consistent long-term operation of these devices.
[0005] With respect to these and other considerations the present
disclosure is provided.
BRIEF SUMMARY
[0006] In one embodiment, a thin film battery may include a cathode
current collector, the cathode current collector being disposed in
a first plane; a device stack disposed on the cathode current
collector, where the device stack comprises an anode current
collector, where the anode current collector is disposed in a
second plane, above the first plane. The thin film battery may
further include a thin film encapsulant, where the thin film
encapsulant is disposed above the device stack, wherein the thin
film encapsulant comprises a first portion extending along a
surface of the anode current collector and a second portion
extending along a plurality of sides of the device stack. The
cathode current collector may extend under the second portion of
the thin film encapsulant and outside of the thin film encapsulant,
and the anode current collector may extend under the first portion
of the thin film encapsulant and outside of the thin film
encapsulant.
[0007] In another embodiment, a method of forming a thin film
battery may include depositing a cathode current collector on a
substrate in a first plane and forming a device stack on the
cathode current collector, where the device stack comprises an
anode current collector. The anode current collector may be
disposed in a second plane above the first plane. The method may
include forming a thin film encapsulant above the device stack,
wherein the thin film encapsulant comprises a first portion
extending along a surface of the anode current collector and a
second portion extending along a side of the device stack. The
cathode current collector may extend under the device stack, under
the second portion of the thin film encapsulant and outside of the
thin film encapsulant. The anode current collector may extend under
the first portion of the thin film encapsulant and outside of the
thin film encapsulant.
[0008] In another embodiment, a method of encapsulating a thin film
battery may include providing an active device region on a
substrate base, wherein the active device region comprises a
cathode current collector and a device stack. The device stack may
be disposed on a portion of the cathode current collector and
include an anode current collector. The method may also include
forming a thin film encapsulant above the device stack, wherein the
thin film encapsulant comprises a first portion extends along a
surface of the anode current collector and a second portion
extending along a side of the device stack. The cathode current
collector may extend under the device stack, under the second
portion of the thin film encapsulant and outside of the thin film
encapsulant, and the anode current collector may extend under the
first portion of the thin film encapsulant and outside of the thin
film encapsulant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1A illustrates a thin film battery according to various
embodiments of the disclosure;
[0010] FIG. 1B provides one embodiment of a thin film battery,
arranged according to embodiments of the disclosure;
[0011] FIGS. 2A-2J illustrates a cross-sectional view of a thin
film battery at various stages of assembly; and
[0012] FIG. 3 shows an exemplary process flow according to
embodiments of the disclosure.
DETAILED DESCRIPTION
[0013] The present embodiments will now be described more fully
hereinafter with reference to the accompanying drawings, where some
embodiments are shown. The subject matter of the present disclosure
may be embodied in many different forms and are not to be construed
as limited to the embodiments set forth herein. These embodiments
are provided so this disclosure will be thorough and complete, and
will fully convey the scope of the subject matter to those skilled
in the art. In the drawings, like numbers refer to like elements
throughout.
[0014] The present embodiments are related to thin film encapsulant
structures and methods, where the thin film encapsulant is used to
minimize ambient exposure of active devices. The present
embodiments provide novel structures and materials combinations for
thin film devices encapsulated using thin film encapsulation.
[0015] Examples of active devices include electrochemical devices
include electrochromic windows and thin film batteries wherein the
active component materials are highly sensitive/reactive to
moisture or other ambient materials. To this end, known
electrochemical devices such as thin film batteries may be provided
with encapsulation to protect the active component materials.
[0016] In various embodiments, a thin film device such as a thin
film battery and techniques for forming a thin film battery are
provided with a novel architecture including an encapsulant
material. The thin film battery may include a layer stack composed
of active layers, as well as the thin film encapsulant, where the
thin film encapsulate also constitutes a multilayer structure.
[0017] In various embodiments novel combinations of thin film
deposition and patterning operations is established, for formation
of an active device region, a thin film encapsulant, or a
combination of active device region and thin film encapsulant.
[0018] According to various embodiments, techniques are provided
for forming thin film batteries exhibiting an improvement in the
structure, the ease of manufacturing, performance, or a combination
of these factors, as compared to known thin film batteries. Various
considerations may affect the design of a thin film battery. A
non-exhaustive list of factors includes the ability of the battery
to accommodate local volume changes within specific regions of the
thin film battery taking place during operation of a battery;
protection from oxidative permeation; and ability to form a device
accounting for large variations in topography. Further factors
include the ability to limit the non-active material in a thin film
battery to an acceptable level; the ability to form a thin film
battery having an acceptable portion of non-active material within
the device regions; and ability to manufacture a thin film battery
using cost-effective techniques. In particular embodiments
disclosed herein, the formation of thin film encapsulation is
integrated with the formation of active device regions of a thin
film battery in a novel manner enabling a more robust architecture
for operation and stability of the thin film battery.
[0019] FIG. 1A illustrates a thin film battery 100 according to
various embodiments of the disclosure. The thin film battery 100
may include a substrate 102. In some embodiments, the substrate 102
may be considered a substrate base forming a part of the thin film
battery 100 or may serve as a support for the thin film battery.
The substrate 102 may be an insulator, semiconductor, or a
conductor, depending upon the targeted electrical properties of the
exterior surfaces. More specifically, the substrate 102 may be made
from a ceramic, metal or glass, such as, for example, aluminum
oxide, silicate glass, or even aluminum or steel, depending on the
application.
[0020] As shown in FIG. 1A, the thin film battery 100 may include a
cathode current collector 104, where the cathode current collector
104 is disposed as a layer on the substrate 102 in a first plane
(parallel to the X-Y plane of the Cartesian coordinate system
shown). The cathode current collector 104 may be a known cathode
current collector such as a metal or metal alloy. The thin film
battery 100 may include a device stack 105, where the device stack
105 is disposed on the cathode current collector 104. The device
stack 105 may include an anode current collector 108, where the
anode current collector 108 is disposed in a non-coplanar
configuration in a second plane, above the first plane of the
cathode current collector 104. The device stack 105 may also
include a portion 106 composed of additional components as in known
thin film batteries, including cathode, electrolyte, and anode in
some cases. The thin film battery 100 may further include a thin
film encapsulant 110 disposed above the device stack 105. The thin
film encapsulant 110 may serve to encapsulate at least a portion of
the device stack 105 to protect the thin film battery 100. As
detailed below, in various embodiments, the thin film encapsulant
110 may include a plurality of layers. As shown in FIG. 1A, the
thin film encapsulant 110 may be patterned to define various
regions where no thin film encapsulant material is present. For
example, in region 120 no thin film encapsulant material is
present, providing a region where a contact to the thin film
battery 100 may be formed. While not shown, contact material, such
as a metal, such as silver, may be provided in the region 120. This
contact material provides a conductive path for forming an external
contact to the cathode side of the thin film battery 100.
Additionally, in region 122 no thin film encapsulant material is
present, providing a region where a contact to the thin film
battery 100 may be formed. This contact provides a conductive path
for forming an external contact to the anode side of the thin film
battery 100.
[0021] In various embodiments, the thin film encapsulant 110 may be
arranged as a thin film encapsulant including a first portion
extending along a surface of the anode current collector 108 and a
second portion extending along a side of the device stack 105. In
particular, as shown in FIG. 1A, the thin film encapsulant 110 may
include a portion 114 extending over the surface 112 of the anode
current collector 108, and a portion 116 extending along a side 115
of the device stack 105. As such, the thin film encapsulant 110
provides at least partial encapsulation of the device stack 105.
For example, while the side 115 is shown as encapsulated,
encapsulation also extends to the right side of device stack 105
(not shown).
[0022] Turning now to FIG. 1B, there is shown a thin film battery
150, where the thin film battery 150 may be a variant of the thin
film battery 100. As shown, the thin film battery 150 may include a
device stack 105, including a cathode 152, where the cathode 152 is
disposed on the cathode current collector 104; and a solid state
electrolyte 154, where the solid state electrolyte 154 is disposed
on the cathode 152 and under the anode current collector 108. In
this variant, the thin film encapsulant 110 includes a plurality of
layers as shown. In particular, the thin film encapsulant 110 may
include a layer stack including a layer 160, a layer 162, a layer
164, a layer 166, a layer 168, and a layer 170. These layers in the
thin film encapsulant 110 may serve multiple functions, including
protecting the device stack 105 from being attacked by oxygen,
water, or other species tending to damage the thin film battery
100. To this end, the thin film encapsulant 110 may encapsulate the
cathode 152, the solid state electrolyte 154, and anode current
collector 108 on the side 115 (see FIG. 1A) of the device stack
105, as well as to the right side (not shown) of the cathode 152,
the solid state electrolyte 154, and anode current collector 108.
Accordingly, the thin film encapsulant 110 includes a first portion
extending along a surface of the anode current collector 108 and a
second portion extending along a side or sides of the device stack
105, including the side 115 and other side to the right (not
shown).
[0023] The thin film encapsulant 110 may further act to accommodate
volume changes occurring in the device stack 105 when the thin film
battery 100 is charged and discharged. For example, in embodiments
where the thin film battery is a lithium battery, the cathode 152
may be a LiCoO.sub.2 material including lithium, where the lithium
diffuses back and forth between the cathode 152 and the anode
current collector 108 during charging and discharging. The lithium
may diffuse through the solid state electrolyte 154, where the
solid state electrolyte 154 may be a known lithium phosphorous
oxynitride (LiPON) material conducting the lithium between the
cathode 152 and an anode region (not specifically shown) in the
device stack 105. As such the lithium may tend to accumulate in a
layer in the anode region during charging or to evacuate the anode
region during discharging, where an effective layer thickness in
the anode region may change by several micrometers or more during
the charging and discharging.
[0024] At least one of the layers of the thin film encapsulant 110
in the embodiment of FIG. 1B may be a soft and pliable polymer
layer useful for accommodating such volume changes in the device
stack 105. In specific embodiments, the term "polymer layer" may
refer to just one polymer layer or to a polymer layer stack
including multiple sub-layers of different polymers, where at least
one sub-layer is soft and pliable. A soft and pliable polymer
layer, either arranged as just one layer, or as a layer stack of
sub-layers, may be characterized by a relatively lower elastic
modulus, relatively high elongation to break, and related
properties. Examples of materials having low elastic modulus
include silicone: hardness of .about.A40 Shore A, Young's Modulus
of .about.0.9 Kpsi or .about.6.2 MPa; Parylene-C: hardness of
.about.Rockwell R80, Young's Modulus of .about.400 Kpsi or
.about.2.8 GPa; KMPR: Young's Modulus of .about.1015 Kpsi or
.about.7.0 GPa; polyimide: hardness of D87 Shore D, Young's Modulus
of .about.2500 Kpsi or .about.17.2 GPa. Examples of a relatively
larger elongation to break include: silicone, 100 to 210%;
Parylene-C, 200%; polyimide, 72%; acrylic, 2.0 to 5.5%; epoxy, 3 to
6%.
[0025] More particularly, as used herein, a "soft and pliable"
material may refer to a material having an elastic (Young's)
modulus less than 20 GPa, for example, while a "rigid material."
such as a rigid metal layer or rigid dielectric layer, may have an
elastic modulus greater than 20 GPa. Other characteristic
properties associated with a soft and pliable material include a
relatively high elongation to break, such as 70% or greater for at
least one polymer layer of the thin film encapsulant. In some
examples, such as silicone, a soft and pliable material may have an
elongation to break up to 200% or greater.
[0026] As an example, the layer 160 may be a soft and pliable
polymer, while the layer 162 may be a rigid material, such as a
rigid metal or a rigid dielectric, such as silicon nitride. The
layer 162 may serve the function of preventing oxygen and water
diffusion into the device stack 105. The sequence layers of a
polymer layer and a rigid dielectric layer may be repeated through
the thin film encapsulant 110. In other words, the thin film
encapsulant 110 may include at least one dyad, wherein a given dyad
includes a soft and pliable polymer layer, and a rigid dielectric
layer disposed adjacent the polymer layer. In particular
embodiments, the layer 164 may be a polymer layer such as a soft
and pliable polymer layer, the layer 166 a rigid dielectric layer
or rigid metal layer, the layer 168 a soft and pliable polymer
layer, and the layer 170 a rigid dielectric layer or rigid metal
layer. While the thin film encapsulant 110 of FIG. 1B includes four
dyads, in other embodiments a thin film encapsulant may include a
greater number or a lesser number of dyads.
[0027] As further illustrated in FIG. 1B, the thin film encapsulant
110 may be arranged as a thin film encapsulant where a polymer
layer, and a rigid dielectric layer or a rigid metal layer, extend
in a non-planar fashion on the device stack 105. In particular the
multiple soft and pliable polymer layers and rigid dielectric
layers of thin film encapsulant 110 may be arranged along the
surface 112 (see FIG. 1A) of the anode current collector 108. These
layers may lie parallel to the X-Y plane (horizontally) in the
portion 114, while these same layers extend more vertically along
the side of the device stack 105 in the portion 116, as shown.
[0028] FIGS. 2A-2J illustrates a cross-sectional view of a thin
film battery at various stages of assembly. In this example, the
final structure 220 illustrated at FIG. 2J may represent a portion
of the thin film battery 150 of FIG. 1B. A particular feature of
the embodiments reflected in FIGS. 2A-2J is a method providing the
integration of a thin film encapsulant with the formation of a
non-coplanar configuration of cathode current collector and anode
current collector layers. The flow of operations shown in FIGS.
2A-2J has the advantage of providing a straightforward process flow
while utilizing substrate area in an efficient manner.
[0029] Turning now to FIG. 2A, there is shown an instance where a
series of layers are disposed on the substrate 102. In particular,
the cathode current collector 104, cathode layer 152A, solid state
electrolyte layer 154A, and anode current collector layer 108A are
formed in a layer sequence above the substrate 102. The cathode
current collector 104, cathode layer 152A, solid state electrolyte
layer 154A, and anode current collector layer 108A may be deposited
in a sequence of blanket depositions in various embodiments. Other
known operations for forming an active device region of a thin film
battery may be performed, such as annealing the substrate after the
depositing the cathode, and before depositing the solid state
electrolyte. Additionally, in some variants, a distinct anode layer
(not shown) may be formed by depositing a lithium anode layer after
the depositing the solid state electrolyte layer 154A and before
the depositing the anode current collector layer 108A.
[0030] In some embodiments, the individual layers may be deposited
using any combination of physical vapor deposition, chemical vapor
deposition, and liquid deposition techniques. The layer thickness
of these layers may be in accordance with thicknesses for known
thin film batteries.
[0031] Turning now to FIG. 2B there is shown a subsequent instance
where the layers shown in FIG. 2A, save the cathode current
collector 104, have been patterned to form a device stack 105. In
various embodiments, the structure of FIG. 2B may be formed by
patterning the cathode layer 152A, the solid state electrolyte
layer 154A, and the anode current collector layer 108A to form the
device stack 105 and to expose the cathode current collector 104,
forming the exposed surface 124, in a first region 202. In some
embodiments, the device stack 105 may be formed by applying a
maskless etching process, such as laser etching to at least one
layer of the device stack 105. In other embodiments, at least one
of the layers of the device stack 105 may be patterned using
masking and etching as in know processes. The formation of the
device stack 105 may take place using any combination of maskless
and masked patterning processes. In various embodiments the
thickness of the device stack 105 may range from 15 micrometers to
60 micrometers. The embodiments are not limited in this context. In
various embodiments, the patterning of the device stack 105 may be
accomplished by using laser ablation of other laser processing as
detailed below, with respect to patterning of a thin film
encapsulant. In brief, select portions of a given layer of the
device stack 105 may be etched using laser ablation where a laser
is rastered over the select portion of the layer to be etched for a
given time and number of repetitions to achieve a target etch
depth. Etching may proceed from the top layer down, which layer may
be the anode current collector 108, where at the end of the
ablation process, the laser intensity is lowered to a level just
below the ablation threshold for the cathode current collector 104.
This lowering of the laser intensity allows removal of the
remaining amount of the cathode 152 in the select portion being
etched, while not etching the cathode current collector 104.
[0032] In various embodiments, the formation of a thin film
encapsulant such as the thin film encapsulant 110 may take place in
a series of operations, as detailed in FIG. 2C to FIG. 2J. Turning
now to FIG. 2C there is shown a subsequent instance involving the
depositing of an initial polymer layer, shown as layer 160, in
blanket form directly on the anode current collector 160 as well as
on the first region 202 of the cathode current collector 104. In
particular embodiments, the initial polymer layer, layer 160, may
be a soft and pliable polymer. The blanket deposition of the layer
160 may be performed in a manner where the layer 160 provides a
conformal coat, so the side 115 of the device stack 105 is also
coated. As such, the layer 160 may extend horizontally in some
regions and vertically in other regions.
[0033] In various embodiments, the layer 160 may include a
plurality of sub-layers, where different sub-layers are arranged to
favor conformality or planarization effects. The choice of
materials and deposition methods for different sub-layers may be
tailored to induce either planarization or conformality. For
example, a first sub-layer may be more conformal to promote
sidewall coverage in a given topography--such as Parylene. The
second sub-layer may be more planarizing for better next-layer
deposition, e.g., spin/dip coating method. The use of multiple
sub-layers within a layer 160, as well as the use of additional
layers in a thin film encapsulant (see layer 162 as discussed
below), may generate additional benefits including improved
adhesion and mechanical properties, as well as limiting reactions
in active regions of a thin film battery.
[0034] Turning now to FIG. 2D there is shown a subsequent instance
where after depositing the initial polymer layer, patterning the
initial polymer layer, layer 160, is performed to form a patterned
polymer layer over a patterned device stack, in other words, over
the device stack 105. This patterning leaves the layer 160 along
the side 115 of the device stack 105 and exposes the cathode
current collector 104 in a second region 204, where the second
region 204 is disposed in the first region 202. In various
embodiments, the patterning the layer 160 may be performed by a
masked patterning process or by a maskless patterning process. In
either a maskless or masked patterning process, the second region
204 is located within the first region 202.
[0035] An advantage of using a maskless patterning process, such as
laser etching, is the avoidance of complexity and costs associated
with known masked patterning processes involving lithography and
dry etching or wet etching. In this manner the complexities of
lithography and etching, the consumable costs, and device effects
are eliminated. In addition, laser based patterning allows device
shape/design to be software recipe based, not depending upon
physical masks, facilitating more rapid, flexible and simpler
design changes.
[0036] In various embodiments, laser patterning may be accomplished
primarily in two ways: using diffractive optics employing
relatively high power to spread the laser beam over larger areas.
This approach may be especially suitable for simple, easily
repeated patterns not having fine pattern details. Another type of
laser patterning especially useful for patterning thin film
batteries according to the present embodiment is direct laser
ablation using a rastering approach. Simple and advanced
galvanometer based scanners may raster the laser beam to form more
complex patterns, and are less limited by feature size and
dimensions. To minimize patterning times, high repetition rate
lasers (>1 MHz) may be used in combination with polygon mirrors
to accomplish high volume production rates.
[0037] Pulse durations of picosecond and femtoseconds have been
shown to be effective for thin film ablation. The use of radiation
wavelengths in the ultraviolet (UV) range, green visible range, as
well as infrared range, including wavelengths ranging from 157 nm
to 1024 nm, may be effectively employed for patterning via laser
ablation the layers of thin film batteries of the present
embodiments, including polymer layers, rigid dielectric layers, and
metal layers. While thin film encapsulant materials are often
transparent or semi-transparent, usable wavelengths may be more
appropriate in the UV or green visible range. Most of the
aforementioned short pulse lasers are DPSS (Diode pumped solid
state) while some fiber based lasers are also contemplated for use
in embodiments of the disclosure.
[0038] In various embodiments, the material of layer 160, such as a
flexible polymer material, and the thickness of the layer 160 may
be arranged to provide benefits, such as accommodating deformation
in the device stack 105 taking place due to transport of lithium
during charging and discharging of a thin film battery to be
formed. Turning now to FIG. 2E and FIG. 2F, there are shown
subsequent operations where a patterned dyad process is performed
after the formation of the patterned initial polymer layer as
exemplified by FIG. 2D. A patterned dyad process may involve
depositing a blanket dyad composed of a rigid dielectric layer and
a polymer layer on device stack 105 and on the cathode current
collector 104. The patterned dyad process may further involve
patterning the blanket dyad to form a patterned thin film
encapsulant over the patterned device stack.
[0039] In the particular example of FIG. 2E, the first part of the
patterned dyad process involves depositing the layer 162, where the
layer 162 may be a rigid dielectric layer, and depositing the layer
164, where the layer 164 may be a polymer layer such as a soft and
pliable polymer layer. The layer 162 and layer 164 may be deposited
as blanket layers, using a physical vapor deposition method,
chemical vapor deposition method, liquid deposition method, other
method, or any combination of these methods.
[0040] Turning now to FIG. 2F there is shown the subsequent
instance where patterning of the layer 162 and layer 164 has been
performed. As illustrated the patterning has the effect to expose
the cathode current collector 104 in a new region, shown as the
region 206, where the new region is disposed in the second region
204. Again, the region 206 may be smaller than the second region
204. The patterning the layer 162 and the layer 164 may be
performed by a masked etching process or by a maskless etching
process. In either a maskless or masked patterning process, the
second region 204 is located within the first region 202. According
to various embodiments, the patterning of the layer 162 and layer
164 may be conducted just one patterning process where just one
etch operation takes place, and just one mask formation process is
used in the case of a masked patterning operation. Alternatively,
the patterning of the layer 162 and layer 164 may employ just one
mask, while a plurality of etch operations are performed, such as
two different etch processes to etch the two different layers.
Additionally, the patterning of the layer 162 and layer 164 may
involve using a masked patterning process for one layer and a
maskless patterning process for the other layer. The embodiments
are not limited in this context.
[0041] After performing a patterned dyad process, this process may
be repeated at least one time to generate a plurality of patterned
dyads, according to some embodiments of the disclosure. Turning now
to FIG. 2G and FIG. 2H, there are shown subsequent operations where
a second patterned dyad process is performed after the instance of
FIG. 2F. The second patterned dyad process involves the deposition
and patterning of the layer 166 and the layer 168, in accordance
with the deposition and patterning described above with respect to
FIGS. 2E and 2F.
[0042] In the particular example of FIG. 2G, the first part of the
second patterned dyad process involves depositing the layer 166,
where the layer 166 may be a rigid dielectric layer, and depositing
the layer 168, where the layer 168 may be a polymer layer such as a
soft and. pliable polymer layer. The layer 166 and layer 168 may be
deposited as blanket layers, as described above with respect to
FIG. 2E.
[0043] Turning now to FIG. 2H there is shown the subsequent
instance where patterning of the layer 166 and layer 168 has been
performed. As illustrated the patterning has the effect to expose
the cathode current collector 104 in a new region, shown as the
region 208, where the new region is disposed in the second region
204. Again, the region 208 may be smaller than the second region
204. The patterning the layer 162 and the layer 164 may be
performed as described above with respect to FIG. 2F.
[0044] Turning now to FIG. 2I and FIG. 2J, there is shown the
operations performed after the instance of FIG. 2H where a final
layer, such as a rigid dielectric layer may be deposited and
patterned. Turning first to FIG. 2I, there is shown the instance
after the depositing of a layer 170, where the layer 170 may be a
rigid dielectric layer. The layer 170 may be deposited in blanket
form by physical vapor deposition, chemical vapor deposition, and
liquid deposition techniques.
[0045] In various embodiments, the formation of a thin film
encapsulant such as the thin film encapsulant 110 may take place in
a series of operations, as detailed in FIG. 2C to FIG. 2J. Turning
now to FIG. 2I there is shown a subsequent instance involving the
depositing of the final rigid dielectric layer, shown as layer 170,
in blanket form.
[0046] Turning now to FIG. 2J there is shown a subsequent instance
where after depositing the final rigid dielectric layer, patterning
the final rigid dielectric layer, layer 170, is performed. As
illustrated the patterning has the effect to expose the cathode
current collector 104 in a new region, shown as the region 210,
where the new region is disposed in the second region 204. Again,
the region 210 may be smaller than the second region 204.
[0047] While not explicitly shown in FIGS. 2A-2J, during the
respective patterning operations, such as those depicted in FIG.
2D, FIG. 2F, FIG. 2H, and FIG. 2J, the thin film battery may be
patterned in other parts of the thin film battery. For example,
returning to FIG. 1B, patterning may be performed in the region 122
during the operations of FIG. 2D, FIG. 2F, FIG. 2H, and 2J, to form
the structure shown, exposing a surface 126 of the anode current
collector 108. Notably, in various embodiment, the patterning
operations generally shown in FIGS. 2B-2J may be carried out in
their entirety using laser etching, such as laser ablation. By
using laser ablation for the sequence of operations shown, a thin
film battery may be formed in a streamlined manner, avoiding cost
and processing complexity associated with known lithographic and
etching processes.
[0048] In addition, and in accordance with embodiments of the
disclosure, a contacting metal may be deposited on the region 210
to form a cathode contact, as well as in the region 122 as shown in
FIG. 1B.
[0049] Turning now to FIG. 3 there is shown an exemplary process
flow 300 according to embodiments of the disclosure. At block 302 a
cathode current collector is deposited on a substrate in a first
plane. At block 304, a device stack is formed on the cathode
current collector, where the device stack includes an anode current
collector disposed in a second plane above the first plane. In
various embodiments the device stack may be formed by depositing a
series of layers and patterning the layers to form a patterned
device stack. The patterned device stack may generate exposed
regions of the cathode current collector, for example. At block
306, a thin film encapsulant is formed above the device stack. In
some embodiments, the thin film encapsulant may be formed in a
series of blanket depositions covering the patterned device stack
and exposed regions, such as regions of the cathode current
collector and anode current collector. The thin film encapsulant
may be patterned so as to form regions above the cathode current
collector and the anode current collector. In particular
embodiments, the thin film encapsulant may be patterned to form a
thin film encapsulant, wherein the thin film encapsulant comprises
a first portion extending along a surface of the anode current
collector and a second portion extending along a side of the device
stack. At the same time the cathode current collector may extend
under the device stack, under the second portion of the thin film
encapsulant and outside of the thin film encapsulant, and the anode
current collector may extend under the first portion of the thin
film encapsulant and outside of the thin film encapsulant.
[0050] There are multiple advantages provided by the present
embodiments, including the ability to protect a device stack of a
thin film battery while maximizing available substrate area, and
the additional advantage of the ability to encapsulate a device
stack in a manner accommodating changes in volume during operation
of the thin film battery.
[0051] The present disclosure is not to be limited in scope by the
specific embodiments described herein. Indeed, other various
embodiments of and modifications to the present disclosure, in
addition to those described herein, will be apparent to those of
ordinary skill in the art from the foregoing description and
accompanying drawings. Thus, such other embodiments and
modifications are intended to fall within the scope of the present
disclosure. Furthermore, the present disclosure has been described
herein in the context of a particular implementation in a
particular environment for a particular purpose, while those of
ordinary skill in the art will recognize the usefulness is not
limited thereto and the present disclosure may be beneficially
implemented in any number of environments for any number of
purposes. Thus, the claims set forth below are to be construed in
view of the full breadth and spirit of the present disclosure as
described herein.
* * * * *