U.S. patent application number 15/338977 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 | 20170301955 15/338977 |
Document ID | / |
Family ID | 60038434 |
Filed Date | 2017-10-19 |
United States Patent
Application |
20170301955 |
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 contact layer, the contact
layer disposed in a first plane and comprising a cathode current
collector and an anode current collector pad; a device stack
disposed on the cathode current collector, the device stack
comprising a cathode and solid state electrolyte; an anode current
collector disposed on the device stack; a thin film encapsulant,
the thin film encapsulant disposed over the device stack, wherein
the solid state electrolyte encapsulates the cathode.
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.: |
15/338977 |
Filed: |
October 31, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62322415 |
Apr 14, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01M 10/0436 20130101;
H01M 4/382 20130101; H01M 2/08 20130101; H01M 10/052 20130101; B23K
2101/36 20180801; B29L 2031/3468 20130101; H01M 2/1094 20130101;
H01M 10/0525 20130101; B23K 26/142 20151001; B23K 2103/172
20180801; H01M 2/0207 20130101; H01M 6/40 20130101; B29C 59/16
20130101; C23C 14/34 20130101; Y02T 10/70 20130101; H01M 2300/0065
20130101; B23K 26/0006 20130101; B23K 26/362 20130101; H01M 2/0267
20130101; H01M 6/188 20130101; C23C 14/50 20130101; H01J 37/3426
20130101; Y02E 60/10 20130101; B29K 2995/0006 20130101; H01M 4/525
20130101; H01M 6/005 20130101; H01M 6/18 20130101; H01M 10/0585
20130101; B23K 2101/34 20180801; H01M 2220/30 20130101; H01J
37/32715 20130101; H01M 2/026 20130101; H01M 2/0287 20130101; H01M
2300/0068 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 contact layer, the contact
layer disposed in a first plane and comprising a cathode current
collector and an anode current collector pad; a device stack
disposed on the cathode current collector, the device stack
comprising a cathode and solid state electrolyte; an anode current
collector disposed on the device stack; and a thin film
encapsulant, the thin film encapsulant disposed over the device
stack, wherein the solid state electrolyte encapsulates the
cathode.
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 polymer layer; and a rigid dielectric
layer disposed adjacent the polymer layer, wherein the polymer
layer and the rigid dielectric layer extend in a non-planar fashion
along a surface of the anode current collector and along a side of
the device stack.
3. The thin film battery of claim 2 wherein the polymer layer
comprises a soft and pliable polymer
4. The thin film battery of claim 3, wherein the anode current
collector comprises a layer thickness of 1 .mu.m to 10 .mu.m.
5. The thin film battery of claim 1, wherein the cathode comprises
a lithium containing material.
6. The thin film battery of claim 1 further comprising a substrate,
the substrate disposed adjacent the cathode current collector in a
first region and adjacent the anode current collector pad in a
second region and adjacent the solid state electrolyte in a third
region.
7. The thin film battery of claim 1, wherein an exposed region of
the cathode current collector comprises a thin interconnect
strip.
8. The thin film battery of claim 1, wherein the device stack
further comprises an anode region, disposed between the solid state
electrolyte and anode current collector.
9. The thin film battery of claim 1, wherein the thin film
encapsulant encapsulates a first side of the device stack, wherein
the anode current collector encapsulates the device stack along a
second side; and wherein the anode current collector is in
electrical contact with the anode current collector pad.
10. The thin film battery of claim 2, wherein the thin film
encapsulant comprises: a first polymer layer, the first polymer
layer disposed on the anode current collector; a rigid metal layer
disposed on the first polymer layer; and the at least one dyad, the
at least one dyad disposed on the rigid metal layer, and arranged
wherein a first rigid dielectric layer of the at least one dyad is
disposed in contact with the rigid metal layer, and wherein a
second polymer layer of the at least one dyad is disposed over the
first rigid dielectric layer.
11. A method of forming a thin film battery, comprising: depositing
a contact layer on a substrate; forming a device stack over the
contact layer, the device stack comprising a cathode, a solid state
electrolyte and an anode current collector, wherein the solid state
electrolyte encapsulates the cathode; and forming a thin film
encapsulant on the substrate after the forming the device
stack.
12. The method of claim 11, wherein the forming the device stack
comprises: depositing a cathode layer on the contact layer;
patterning the contact layer and the cathode layer, wherein the
substrate is exposed, and wherein the contact layer forms a cathode
current collector and an anode current collector pad, and the
cathode layer forms the cathode; depositing a solid state
electrolyte layer on the cathode; patterning the solid state
electrolyte layer to expose the anode current collector pad;
depositing an anode current collector layer on the substrate; and
patterning the anode current collector layer and the solid state
electrolyte layer, wherein the cathode current collector is exposed
in a first region, wherein the patterning the contact layer and the
cathode, the solid state electrolyte, and the anode current
collector, comprise laser etching select portions of the contact
layer and the cathode, the solid state electrolyte, and the anode
current collector.
13. The method of claim 12, wherein the forming the thin film
encapsulant comprises: depositing a polymer layer on the substrate;
and and patterning the polymer layer to form a patterned polymer
layer, wherein the cathode current collector is exposed in a first
region and the anode current collector is exposed in a second
region.
14. The method of claim 13, further comprising: depositing a rigid
dielectric layer on the patterned polymer layer; and depositing a
second polymer layer on the rigid dielectric layer; and patterning
the rigid dielectric layer and the second polymer layer, wherein
the cathode current collector is exposed in a first inner region,
wherein the anode current collector is exposed in a second inner
region, the first inner region being disposed within the first
region, and the second inner region being disposed in the second
region.
15. The method of claim 14, further comprising after the patterning
the rigid dielectric layer and the second polymer layer: depositing
an additional rigid dielectric layer on the second polymer layer;
and patterning the additional rigid dielectric layer, wherein the
cathode is exposed in a third inner region, the third inner region
being disposed within the first region, and wherein the anode
current collector is exposed in a fourth inner region, the fourth
inner region being disposed in the second region, wherein the
patterning the polymer layer, the rigid dielectric layer, the
second polymer layer, and the additional rigid dielectric layer
comprise laser etching select portions of the polymer layer, the
rigid dielectric layer, the second polymer layer, and the
additional rigid dielectric layer.
16. The method of claim 11, wherein the anode current collector
comprises a layer thickness of 1 .mu.m to 10 .mu.m.
17. The method of claim 12, wherein the first region of the cathode
current collector comprises a thin interconnect strip.
18. The method of claim 12, wherein the patterning the contact
layer and the cathode layer comprises patterning the cathode layer
in a first operation and patterning the contact layer in a second
operation, subsequent to the first operation.
19. A method of forming a thin film battery, comprising: depositing
a contact layer on a substrate and depositing a cathode layer on
the contact layer; patterning the contact layer and the cathode
layer, wherein the substrate is exposed, and wherein the contact
layer forms a cathode current collector and an anode current
collector pad, and the cathode layer forms a cathode; depositing a
solid state electrolyte layer on the substrate after the patterning
the contact layer and the cathode layer; patterning the solid state
electrolyte layer, wherein the anode current collector pad is
exposed; depositing an anode current collector layer on the
substrate after the patterning the solid state electrolyte layer;
patterning the anode current collector layer and the solid state
electrolyte layer, wherein the cathode current collector is
exposed; depositing a polymer layer on the substrate after the
patterning the anode current collector layer and the solid state
electrolyte layer; and patterning the polymer layer to form a
patterned polymer layer, wherein the cathode current collector is
exposed in a first region.
20. The method of claim 19, further comprising: depositing a rigid
metal layer on the patterned polymer layer; patterning the rigid
metal layer to and the patterned polymer layer, wherein a patterned
rigid metal layer is formed, and wherein the anode current
collector layer is exposed in a second region; depositing at least
one dyad on the patterned rigid metal layer, wherein the at least
one dyad comprises a rigid dielectric layer and a second polymer
layer disposed on the rigid dielectric layer; and patterning the at
least one dyad, wherein the cathode current collector is exposed in
a first inner region, wherein the anode current collector is
exposed in a second inner region, the first inner region being
disposed within the first region, and the second inner region being
disposed in the second region.
Description
RELATED APPLICATIONS
[0001] This Application claims priority to U.S. provisional patent
application 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 based
encapsulation 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, thin film encapsulation approaches for these types
of devices, such as thin film batteries, are far more challenging
for several reasons. Firstly, accommodation of volume changes
taking place during battery operation is useful, in order to reduce
potential stress to a thin film encapsulant during device
operation. Secondly, a main function of the thin film encapsulant
is to provide good oxidant permeation barrier properties. Moreover,
a thin film encapsulant may be used to encapsulate device
structures including a larger topography variation. At the present,
robust thin film encapsulant fabrication methods and the resulting
device architectures are lacking for providing robust and uniform
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
contact layer, where the contact layer is disposed in a first plane
and comprising a cathode current collector and an anode current
collector pad. The thin film battery may further include a device
stack disposed on the cathode current collector, the device stack
comprising a cathode and solid state electrolyte; an anode current
collector disposed on the device stack. The thin film battery may
also include a thin film encapsulant, where the thin film
encapsulant is disposed over the device stack, wherein the solid
state electrolyte encapsulates the cathode.
[0007] In another embodiment, a method of forming a thin film
battery may include depositing a contact layer on a substrate and
forming a device stack over the contact layer, where the device
stack comprising a cathode, a solid state electrolyte and an anode
current collector, wherein the solid state electrolyte encapsulates
the cathode. The method may also include forming a thin film
encapsulant on the substrate after the forming the device
stack.
[0008] In another embodiment, a method of forming a thin film
battery may include depositing a contact layer on a substrate and
depositing a cathode layer on the contact layer. The method may
also include patterning the contact layer and the cathode layer,
wherein the substrate is exposed, and wherein the contact layer
forms a cathode current collector and an anode current collector
pad, and the cathode layer forms a cathode. The method may also
include depositing a solid state electrolyte layer on the substrate
after the patterning the contact layer and the cathode layer
patterning the solid state electrolyte layer, wherein the anode
current collector pad is exposed. The method may further include
depositing an anode current collector layer on the substrate after
the patterning the solid state electrolyte layer and patterning the
anode current collector layer and the solid state electrolyte
layer, wherein the cathode current collector is exposed. The method
may also include depositing a polymer layer on the substrate after
the patterning the anode current collector layer and the solid
state electrolyte layer and patterning the polymer layer to form a
patterned polymer layer, wherein the cathode current collector is
exposed in a first region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1A illustrates a cross-section of a thin film battery
according to various embodiments of the disclosure;
[0010] FIG. 1B provides a plan view of a thin film battery
according to embodiments of the disclosure;
[0011] FIG. 1C provides a plan view of a thin film battery
arrangement in a substrate according to embodiments of the
disclosure;
[0012] FIGS. 2A-2K illustrate a cross-sectional view of a thin film
battery at various stages of assembly;
[0013] FIG. 3 illustrates a cross-section of another thin film
battery according to additional embodiments of the disclosure;
[0014] FIG. 3 shows an exemplary process flow according to
embodiments of the disclosure.
[0015] FIGS. 4A-4D illustrate a cross-sectional view of another
thin film battery at various stages of assembly;
[0016] FIG. 4E provides a plan view of the thin film battery of
FIG. 4D;
[0017] FIG. 5 illustrates a cross-section of a thin film battery
according to various additional embodiments of the disclosure;
[0018] FIG. 6A-6D illustrate a cross-sectional view of another thin
film battery at various stages of assembly; and
[0019] FIG. 7 illustrates an exemplary process flow.
DETAILED DESCRIPTION
[0020] 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.
[0021] The present embodiments are related to thin film
encapsulation (TFE) technology, where a thin film encapsulant is
used to minimize ambient exposure of active devices. The present
embodiments provide novel structures and materials combinations for
thin film encapsulation.
[0022] 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.
[0023] 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 encapsulant may also constitute a multilayer
structure.
[0024] In various embodiments novel combinations of thin film
deposition and patterning operations are provided, for formation of
an active device region, a thin film encapsulant, or a combination
of active device region and thin film encapsulant. In particular,
techniques are provided for forming thin film batteries, where the
techniques provide 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; ability from a thin film battery having an
acceptable portion of non-active material within the device
regions; and the 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.
[0025] FIG. 1A illustrates a cross-section of a thin film battery
130 according to various embodiments of the disclosure. FIG. 1B
provides a plan view of a variant of a thin film battery according
to embodiments of the disclosure. In particular, FIG. 1A
illustrates an arrangement 100 where at least one thin film
battery, shown as thin film battery 130, is arranged on a substrate
102. FIG. 1C provides a plan view of a thin film battery
arrangement 150 in a substrate according to embodiments of the
disclosure. The arrangement of FIG. 1C may include a matrix of thin
film batteries, such as thin film batteries 130.
[0026] Turning now to FIG. 1A, the substrate 102, used for
supporting the thin film battery 130, 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. The substrate 102 may
include any number of parts or layers, including adhesion layer(s)
(not shown) as an interface to layers to be formed on the substrate
102.
[0027] As shown in FIG. 1A, the thin film battery 130 may include a
contact layer 104, where the contact layer 104 is disposed in a
first plane (parallel to the X-Y plane of the Cartesian coordinate
system shown). The contact layer 104 may be arranged in different
parts and may include a cathode current collector 106 and an anode
current collector pad 108. The contact layer 104 may be formed from
a known metal or metal alloy used in known thin film batteries. The
thin film battery 130 may further include a device stack 110, where
the device stack 110 is disposed on the cathode current collector
106. As shown, the device stack 110 may include a cathode 112 and
solid state electrolyte 114. For example, in embodiments where the
thin film battery 130 is a lithium battery, the cathode 112 may be
a LiCoO.sub.2 material containing lithium, where the lithium
diffuses back and forth between the cathode 112 an anode current
collector 116 during charging and discharging. During operation,
the lithium may diffuse through the solid state electrolyte 114,
where the solid state electrolyte 114 may be a known lithium
phosphorous oxynitride (LiPON) material appropriate for conducting
the lithium between the cathode 112 and an anode region 115 in the
device stack 110.
[0028] While not shown in FIG. 1A as a distinct layer, according to
embodiments of the disclosure, a thin film battery such as thin
film battery 130, may include the anode region 115, shown in the
dashed area, where the anode region 115 is disposed between the
solid state electrolyte 114 and anode current collector 116. The
anode region 115 may represent a region where lithium, accumulates
within, or diffuses away from, as the thin film battery 130 charges
and discharges. This reversible transport of material such as
lithium may cause changes in dimensions in the anode region 115,
where such changes may be on the order of microns, leading to
distortions within the thin film battery, including in the thin
film encapsulant 120. Notably, in additional embodiments as
disclosed below in FIG. 4A, FIG. 5, and FIG. 6A, an anode region is
understood to exist between an anode current collector and solid
state electrolyte.
[0029] As shown in FIG. 1A, at least a portion of the anode current
collector 116 is disposed on the device stack 110. As also shown in
FIG. 1A, the thin film battery 130 may further include a thin film
encapsulant, shown as thin film encapsulant 120, where the thin
film encapsulant 120 is disposed over a top portion of the device
stack 110. More particularly, the thin film encapsulant 120 may be
disposed directly on the anode current collector 116. As shown, the
thin film encapsulant 120 may encapsulate the device stack 110 on a
first side (to the left in FIG. 1A) of the device stack 110. As
further shown in FIG. 1A, the thin film battery 130 may be
advantageously formed in a manner wherein the anode current
collector 116 encapsulates the device stack 110 along a second
side.
[0030] As further shown in FIG. 1A, a hallmark of the thin film
battery 130 is the structure of the solid state electrolyte 114,
where the solid state electrolyte 114 encapsulates the cathode 112.
Advantageously, the cathode sidewalls 111 of cathode 112 may
accordingly be protected by the solid state electrolyte 114 when
the thin film encapsulant 120 is breached be species from outside
of the thin film battery 130. Further advantageously, during
cycling of the thin film battery 130, when Li species are
transported from the cathode 112 toward the anode current collector
116, the Li species may become "trapped" between the solid state
electrolyte 114 and the metal layer of the anode current collector
116.
[0031] As further shown in FIG. 1A, the thin film battery 130 may
include a cathode contact 122 and anode contact 124, which contacts
may be formed of a known metal, such as silver. The embodiments are
not limited in this context. According to some embodiments of the
disclosure, the thin film encapsulant 120 may be formed from at
least one dyad, where a given dyad includes a polymer layer and a
rigid layer, such as a rigid dielectric layer or rigid metal layer
disposed adjacent the polymer layer. In various embodiments, the
dyad may act as a "functional dyad" where at least one layer of the
functional dyad provides a diffusion barrier to contaminants such
as moisture and gas species, and at least one layer includes a soft
and pliable layer for accommodating changes in dimension of an
active device region in a reversible manner. Examples of a dyad
include a combination of a polymer layer for a first layer, and a
rigid diffusion barrier layer, such as a dielectric layer or a
rigid metal layer for the second layer, or combinations of a rigid
metal layer and rigid dielectric layer. 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 rigid
metal layer may include Cu, Al, Pt, Au, or other metal. The
embodiments are not limited in this context. In particular
embodiments the polymer layer may constitute a soft and pliable
polymer, or at least one polymer sub-layer of a polymer layer may
be formed from a soft and pliable polymer, where a soft and pliable
polymer is characterized by a relatively lower elastic modulus.
Suitable polymers with 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). Other useful properties include a relatively larger
elongation to break (e.g. Silicone, 100 to 210%; Parylene-C, 200%;
polyimide, 72%; acrylic, 2.0 to 5.5%; epoxy, 3 to 6%), and related
properties. In the example of FIG. 1A the thin film encapsulant
includes three dyads, while in other embodiments a greater number
or fewer number of dyads may be used to form a thin film
encapsulant.
[0032] 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.
[0033] Turning now to FIG. 1B, there is shown a plan view of a
variant of the thin film battery 130, showing a cathode current
collector region 132 and an anode current collector region 134,
where the two regions have generally circular shape. In other
embodiments such regions may have other shapes, such as a
rectangular shape. The area defined by the inner most line outside
of cathode current collector region 132 and anode current collector
region 134 defines the active device region, while various other
lines represent the overlap/edges of various components/layers of
the thin film encapsulant. Turning now to FIG. 1C there is shown a
thin film battery arrangement 150 made from a two dimensional array
of the thin film batteries 130. This array may be formed by
patterning a plurality of batteries by performing a plurality of
thin film deposition operations to deposit the different components
of thin film batteries 130, as well as patterning operations to
define individual batteries, as well as components within the
individual batteries.
[0034] As further shown in FIG. 1A, and detailed in the figures to
follow, in various embodiments, the structure of a TFE stack may
include a plurality of layers wherein a polymer layer and a rigid
dielectric layer extend in a non-planar fashion. For example, a
first portion 121 may extend along the surface of the anode current
collector 116 and a second portion 123 may extend along the side of
the device stack 110. In this manner, material diffusing from the
outside of thin film battery 130 is presented with multiple
different layers to diffuse through before contacting the device
stack 110, whether penetrating from the top of the thin film
battery 130 or from the side of the thin film battery 130. While
drawn as individual layer, the thin film encapsulant layers, such
as a polymer layer, may comprise a multiple layer configuration of
comparable materials, or differing materials, such as different
types of polymer sub-layers within a polymer "layer" configured as
a multilayer polymer stack.
[0035] As further shown in FIG. 1A, the substrate 102 may act as a
base for forming the thin film battery 130. The configuration of
thin film battery 130 of FIG. 1A may be deemed to be a co-planar
configuration, where the substrate 102, is disposed adjacent the
cathode current collector 106 in a first region, adjacent the anode
current collector pad 108 in a second region, and adjacent the
solid state electrolyte 114 in a third region. In other words, the
cathode current collector 106 is disposed in a coplanar
configuration with the anode stack 109, where the anode stack 109
includes the anode current collector pad 108 and a portion of the
anode current collector 116 in electrical contact with the anode
current collector pad 108.
[0036] In sum, the thin film battery 130 provides multiple ways of
encapsulating components of a device stack. In addition to the
encapsulation provided by solid state electrolyte 114, the thin
film encapsulant 120 encapsulates a first side of the device stack
110, while the anode current collector 116 encapsulates the device
stack 110 along a second side.
[0037] FIGS. 2A-2K illustrate a cross-sectional view of a thin film
battery at various stages of assembly. Turning to FIG. 2A, there is
shown an instance where a contact layer 104 and cathode layer 112A
have been deposited in blanket form on the substrate 102. According
to various embodiments, the contact layer 104 and cathode layer
112A may be deposited using known deposition techniques, including
using any combination of physical vapor deposition, chemical vapor
deposition, liquid deposition techniques. The layer thickness of
these layers may be consistent with thicknesses for known thin film
batteries. The contact layer 104 in particular may constitute a
material used for known cathode current collectors in known
batteries, such as Ti/Pt or other metal material.
[0038] At FIG. 2B, there is shown a subsequent instance where the
contact layer 104 and cathode layer 112A have been patterned. In
particular, the substrate 102 is exposed in a region 204, the
contact layer 104 forms the cathode current collector 106 and the
anode current collector pad 108 as described above, and the cathode
layer 112A forms the cathode 112. In some embodiments, the contact
layer 104 and cathode layer 112A may be patterned in separate
operations. For example, the cathode layer 112A may first be
patterned to remove material of the cathode layer 112A, leaving
just the cathode 112 as shown. The patterning may take place using
a maskless patterning process such as laser etching, or a masked
process where a mask may be deposited and defined in a lithographic
process, so as to provide exposed regions of the cathode layer 112A
for removal in an etching process, as known in the art.
[0039] 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.
[0040] 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.
[0041] 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 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
rigid 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.
[0042] After patterning to form the cathode 112, a surface 208 of
the contact layer 104 is exposed on the cathode current collector
106 as well as on the anode current collector pad 108.
Subsequently, the contact layer 104 may be etched in a masked or
maskless operation to define the region 204 where the surface 206
of substrate 102 is exposed.
[0043] Turning now to FIG. 2C, there is shown an instance after the
depositing of a solid state electrolyte layer 114A on the cathode
112. The solid state electrolyte layer 114A may be formed as a
blanket layer as shown, where the surface 206 of substrate 102 as
well as the cathode current collector 106 and the anode current
collector pad 108 are covered. Turning now to FIG. 2D there is
shown a subsequent instance after patterning of the solid state
electrolyte layer 114A to form the partially patterned solid state
electrolyte layer 114B, and to expose the anode current collector
pad 108 in the region 210 for forming an electrical contact during
later processing. In different embodiments, the patterning of the
solid state electrolyte layer 114A may be performed by any know
patterning technique including maskless patterning or masked
patterning as discussed above. At this stage of processing, the
partially patterned solid state electrolyte layer 114B may
encapsulate the entirety of cathode 112.
[0044] Turning now to FIG. 2E there is shown an instance where a
blanket layer shown as anode current collector layer 116A has been
deposited on the substrate configuration of FIG. 2D. As shown, the
anode current collector layer 116A is formed on the partially
patterned solid state electrolyte layer 114B and the anode current
collector pad 108. The anode current collector layer 116A may be
formed of a known metal or combination of metals, such as copper.
In some embodiments, an additional anode or anode current collector
layers may be deposited before and after the formation of the anode
current collector layer 116A.
[0045] Turning now to FIG. 2F, there is shown a subsequent instance
after patterning of the anode current collector layer 116A and
additional patterning of the partially patterned solid state
electrolyte layer 114B, wherein the cathode current collector 106
is exposed in a first region, shown as region 212. At this stage of
processing the solid state electrolyte 114 and the anode current
collector may be in final form for the battery to be fabricated.
The solid state electrolyte 114 continues to encapsulate the
cathode 112 as shown. In some embodiments, the anode current
collector layer 116A and partially patterned solid state
electrolyte layer 114B may be patterned in separate operations. For
example, the anode current collector layer 116A may first be
patterned to remove material of the anode current collector layer
116A, leaving just the anode current collector 116 as shown. The
patterning may take place using a maskless patterning process such
as laser etching, or a masked process where a mask may be deposited
and defined in a lithographic process, so as to provide exposed
regions of the anode current collector layer 116A for removal in an
etching process, as known in the art. After patterning to form the
anode current collector 116, the partially patterned solid state
electrolyte layer 114B may be etched in a masked or maskless
operation to define the region 212 where the surface 208 of cathode
current collector 106 is exposed.
[0046] Turning now to FIG. 2G there is shown an instance after
depositing a polymer layer or a stack of polymer layers, shown as
the polymer layer 220A, on the substrate 102. More particularly,
the polymer layer 220A is disposed on the anode current collector
116, on the cathode current collector 106 and along a side of the
solid state electrolyte 114. The polymer layer 220A may be
deposited as a blanket layer by known processes. In various
embodiments, the polymer layer 220A may be a soft and pliable
polymer layer or multiple layer stack where at least one layer is a
soft and pliable polymer layer. The polymer layer 220A may be
configured to accommodate volume changes during operation of a
battery to be formed, particularly in regions of the device stack
110 (as shown in FIG. 1A). Turning now to FIG. 211 there is shown a
subsequent instance after patterning the polymer layer 220A (shown
in FIG. 2G) to form a patterned polymer layer 220, wherein the
cathode current collector 106 is exposed in a first region 214 and
the anode current collector 116 is exposed in a second region
216.
[0047] In various embodiments the polymer layer 220A may form a
first part of a thin film encapsulant to be formed. Depending upon
various considerations including the total thickness of the battery
to be formed, the degree of protection, and robustness of the
battery, a number of additional layers of a thin film encapsulant
may be added. Turning now to FIG. 2I and FIG. 2J, 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. 2H. A patterned dyad process may involve
depositing a blanket dyad composed of a rigid dielectric layer and
a polymer layer, followed by patterning the blanket dyad to form a
patterned thin film encapsulant including a plurality of
layers.
[0048] Turning in particular to FIG. 21, there is shown a
subsequent instance after the depositing of a rigid dielectric
layer 222A on the patterned polymer layer 220 and after the further
depositing a second polymer layer 224A on the rigid dielectric
layer 222A. Again, the rigid dielectric layer 222A and second
polymer layer 224A may be deposited using known blanket deposition
processes. The rigid dielectric layer 222A may in particular,
provide resistance against diffusion of unwanted species into
active regions of the thin film battery to be fabricated, where the
active regions may include the cathode, solid state electrolyte,
and anode, for example.
[0049] Turning now to FIG. 2J, there is shown a subsequent instance
after the patterning the rigid dielectric layer 222A and the second
polymer layer 224A. At this instance, the patterned rigid
dielectric layer 222 and the patterned second polymer layer 224 are
formed, where the cathode current collector 106 is exposed in a
first inner region 218, and the surface 217 of the anode current
collector 116 is exposed in a second inner region 219. As
illustrated by comparison to FIG. 2H, the first inner region 218 is
disposed within the first region 214, and the second inner region
219 is disposed in the second region 216.
[0050] According to various embodiments of the disclosure, a thin
film encapsulant may be completed by forming a top layer composed
of a rigid dielectric layer. In some embodiments, the patterned
dyad process as depicted in the operations of FIG. 2I and FIG. 2J
may be repeated at least one time to generate a thicker thin film
encapsulant, before forming a final layer composed of a rigid
dielectric layer. Turning now to FIG. 2K, there is shown a
subsequent instance after performing a second patterned dyad
process, forming the layer 226 and the layer 228, and after the
depositing and patterning of an additional rigid dielectric layer,
shown as the layer 230. The final structure of the thin film
encapsulant thus formed includes three dyads, where a given dyad
includes a polymer layer and rigid dielectric layer. After the
formation of the thin film encapsulant, a cathode contact 122 and
an anode contact 124 may be formed as shown.
[0051] FIG. 3 illustrates a cross-section of an arrangement 300
including another type of thin film battery 330, according to
further embodiments of the disclosure. As shown, the thin film
battery 330 may be formed using a substrate 102, formed of any
material as disclosed previously with respect to FIG. 1A. In some
embodiments the anode current collector pad 108, cathode current
collector 106, cathode 112, and solid state electrolyte 114 may be
configured as in the thin film battery 130. Notably, in the thin
film battery 330 a thin film encapsulant 304 is provided, where the
thin film encapsulant 304 may include fewer layers as opposed to
the thin film battery 130. For example, the thin film encapsulant
304 may include just one layer, such as a polymer layer. Another
hallmark of the thin film battery 330 is the provision of a thicker
anode current collector, shown as anode current collector 302,
where the thickness of the anode current collector 302 may be 1
.mu.m to 10 .mu.m, and in some examples greater than 10 .mu.m. An
advantage provided by the thin film battery 330 is a relatively
simpler process for forming the thin film encapsulant 304, as well
as a relatively shallower topography, along the Z-axis. In
particular, in addition to the protection of the cathode 112
provided by the solid state electrolyte 114, the thicker anode
current collector may provide additional encapsulation, while
allowing a much thinner thin film encapsulant to be used to provide
adequate encapsulation for the thin film battery 330.
[0052] While in some embodiments a thin film encapsulant such as
thin film encapsulant 120 may include a plurality of layers, the
embodiments are not limited in this context. In other embodiments,
a thin film encapsulant of a thin film battery may be formed of a
unitary layer, meaning the thin film encapsulant is composed of
just one layer. In such embodiments, and as described below with
respect to FIGS. 4A-4D, an improved anode current collector may be
provided in the thin film battery to provide adequate encapsulation
when used in conjunction with a thin film encapsulant formed of
just one layer. For example in embodiments where a thin film
encapsulant is formed of just one layer, the anode current
collector comprises a layer thickness of at least five micrometers.
FIGS. 4A-4D illustrate a cross-sectional view of another thin film
battery at various stages of assembly. Turning to FIG. 4A, there is
shown an instance where the cathode current collector 106, anode
current collector pad 108, cathode 112 and partially patterned
solid state electrolyte layer 114B have been formed in accordance
with the procedures outlined above with respect to FIGS. 2A-2D. In
addition, an anode current collector layer 302A has been deposited
in blanket form, covering the solid state electrolyte 114 and anode
current collector pad 108. The anode current collector layer 302A
may be arranged as an extra thick metal layer having a thickness of
at least 1 .mu.m to 10 .mu.m.
[0053] Turning now to FIG. 4B, there is shown a subsequent instance
after patterning of the anode current collector layer 302A and
additional patterning of the partially patterned solid state
electrolyte layer 114B, wherein the cathode current collector 106
is exposed in a first region, shown as region 212. At this stage of
processing the solid state electrolyte 114 and the anode current
collector 302 may be in final form for the battery to be
fabricated. The solid state electrolyte 114 continues to
encapsulate the cathode 112 as shown. In some embodiments, the
anode current collector layer 302A and partially patterned solid
state electrolyte layer 114B may be patterned in separate
operations. For example, the anode current collector layer 302A may
first be patterned to remove material of the anode current
collector layer 302A, leaving just the anode current collector 302
as shown. The patterning may take place using a maskless patterning
process such as laser etching, or a masked process where a mask may
be deposited and defined in a lithographic process, so as to
provide exposed regions of the anode current collector layer 302A
for removal in an etching process, as known in the art. After
patterning to form the anode current collector 302, the partially
patterned solid state electrolyte layer 114B may be etched in a
masked or maskless operation to define the region 212 where the
surface 208 of cathode current collector 106 is exposed.
[0054] Turning now to FIG. 4C there is shown an instance after
depositing a polymer layer 304A on the substrate 102, or more
particularly on the anode current collector 302, on the cathode
current collector 106 and along a side of the solid state
electrolyte 114. The polymer layer 304A may be deposited as a
blanket layer by known processes. In various embodiments, the
polymer layer 304A may be a soft and pliable polymer layer or
multiple layer stack of at least two polymer sub-layers. The
polymer layer 304A may be configured to accommodate volume changes
during operation of a battery to be formed, particularly in regions
of the device stack 110 (as shown in FIG. 1A).
[0055] Turning now to FIG. 4D there is shown a subsequent instance
after patterning the polymer layer 304A to form a patterned polymer
layer, shown as the thin film encapsulant 304. At the instance of
FIG. 4d the cathode current collector 106 is exposed in a first
region 402 and the anode current collector 302 is exposed in a
second region 404. Subsequently, electrical contacts may be formed
to the first region 402 and the second region 404, to complete the
thin film battery 330. As shown in FIG. 4E, the cathode current
collector 106 may include a thin interconnect strip. Notably, after
the process shown in FIG. 4D, a capping layer such as a rigid
dielectric or rigid metal layer may be formed on the polymer layer
304A to provide a permeation blocking layer, to provide diffusion
resistance to moisture, gas species or other species.
[0056] FIG. 5 illustrates a cross-section of a thin film battery
500 according to various additional embodiments of the disclosure.
The thin film battery 500 may be formed generally as described
above with the same front end configuration up to FIG. 2G, where
the cathode, solid state electrolyte, and anode regions are formed
as previously described. Additionally, the layer 220, forming a
first layer of a thin film encapsulant, may be formed as detailed
above. Notably, the thin film battery 500 includes a different thin
film encapsulant, shown as thin film encapsulant 502. In this
embodiment, the thin film encapsulant 502 includes at least one
rigid metal layer, shown as layer 530, and at least one dielectric
layer in addition to the patterned polymer layer 220 (polymer)
layer. The layer 530 represents a patterned rigid metal layer,
after the thin film encapsulant 502 has been completed.
[0057] As shown, the thin film battery 500 has a first region 510
where the cathode current collector 106 may be contacted, as well
as a second region 520 where the anode current collector 116 may be
contacted. After formation of the thin film encapsulant 502, the
cathode current collector 106 is exposed in a first inner region
512, the anode current collector 116 is exposed in a second inner
region 522. Notably the first inner region 512 is disposed within
the first region 510, and the second inner region 522 is disposed
in the second region 520.
[0058] In the thin film battery 500, the thin film encapsulant 502
may include at least one dyad, where the at least one dyad is
generally disposed on the rigid metal layer, and arranged wherein a
first rigid dielectric layer of the at least one dyad is disposed
in contact with the rigid metal layer. Advantages of this
configuration include the improved permeation blocking provided by
a rigid metal layer, i.e., the increased resistance to diffusion of
species such as moisture or gas. In particular, by providing a
rigid metal layer adjacent polymer layer 202, instead of a rigid
dielectric layer, volume changes in the thin film battery 500 may
more easily be accommodated in the thin film encapsulant 502. In
particular, when the thin film encapsulant 502 is subjected to
flexing or other mechanical force, caused by changes in volume in
the anode region (see anode region 115), a rigid metal layer may
deform (elastically or plastically) more readily than a rigid
dielectric. This deformation may allow a rigid metal layer within
the thin film encapsulant 502 to remain intact even while a rigid
dielectric layer may crack, thus preserving diffusion barrier
properties. This ability to remain intact may be especially useful
in configurations where an underlying polymer layer, such as the
layer 220, is not able to accommodate the entirety of deformations
taking place in the anode region.
[0059] FIGS. 6A-6D illustrate a cross-sectional view of a thin film
battery at various stages of assembly. Continuing from a processing
stage shown generally at FIG. 2G, in FIG. 6A there is shown the
result of an additional operation where a portion of the polymer
layer 220A is removed to form a contact region 602 above the
cathode current collector 106. This patterning results in the
formation of the layer 220B where the opening to form the contact
region 602 may be formed by laser patterning.
[0060] Turning to FIG. 6B, in a subsequent operation, a rigid metal
layer 604 may be deposited by blanket deposition. The thickness of
the rigid metal layer 604 may range from 1 .mu.m to 5 .mu.m in
various embodiments. Examples of metals appropriate for use as
rigid metal layer 604 include Al, Cu, Ti, Pt, Au, etc. Turning now
to FIG. 6C, there is shown a subsequent operation where a portion
of the rigid metal layer 604 and the layer 220B are etched in the
contact region 606, so as to provide for contacting the anode
current collector 116. As shown, the patterned polymer layer 220 is
now formed. Turning now to FIG. 6D there is shown a subsequent
operation where a dyad 608 is deposited on the structure of FIG.
6C. The dyad 608 may be made of a polymer layer and a rigid
dielectric layer in some embodiments. While just one dyad is shown
in FIG. 6D, in some embodiments a plurality of dyads 608 may be
formed. After a targeted number of dyads is formed, resulting in
the thin film encapsulant 610, etching of the thin film encapsulant
610 may be performed to form openings for contacting the cathode
current collector 106 and anode current collector 116, generally as
shown, for example in FIG. 5. To arrive at the thin film
encapsulant 502 shown in FIG. 5, for example, two dyads may be
deposited over the rigid metal layer 604, where a given dyad is
composed of a rigid dielectric layer followed by a polymer layer.
On top of the two dyads, layer 220B and rigid metal layer 604, a
last layer formed from a rigid dielectric may be deposited.
[0061] In the above process sequence, a rigid metal layer, such as
copper may be incorporated into a thin film encapsulant, while
electrically isolating the rigid metal layer from the anode current
collector 116.
[0062] FIG. 7 illustrates an exemplary process flow 700. At block
702, a contact layer is deposited on a substrate. In various
embodiments, the contact layer may be formed from a known metal or
metal alloy used in known thin film batteries. At block 704, a
cathode layer is deposited on the contact layer. The cathode layer
may be formed of a material such as LiCoO.sub.2 in some
embodiments. At block 706 the contact layer and cathode layer are
patterned, wherein the substrate is exposed. The patterning of the
contact layer and cathode layer may be performed together or the
contact layer may be patterned separately from patterning of the
cathode layer. As a result of the patterning the contact layer may
form a cathode current collector and anode current collector. The
cathode layer may also form a cathode as a result of the
patterning.
[0063] At block 708 a solid state electrolyte layer is deposited on
the substrate after the patterning of the contact layer and the
cathode layer. At block 710, the solid state electrolyte layer is
patterned wherein the anode current collector pad is exposed.
[0064] At block 712, an anode current collector layer is deposited
on the solid state electrolyte layer. At block 714 the anode
current collector layer and solid state electrolyte layer are
patterned, wherein the cathode current collector is exposed. At
block 716, a thin film encapsulant is formed on the substrate after
the patterning of the anode current collector layer and the solid
state electrolyte layer. In some embodiments the thin film
encapsulant may include a plurality of layers, such as at least one
polymer layer and at least one rigid layer. In other embodiments
the thin film encapsulant may be just one layer.
[0065] There are multiple advantages provided by the present
embodiments, including the advantage of the provision of multiple
encapsulation features to protect active regions of a thin film
battery. Another advantage is the ability to reduce the topography
of a thin film battery by providing encapsulation features formed
within active portions of the thin film battery such as in the thin
film electrolyte.
[0066] 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 in the tended 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.
* * * * *