WO2017053862A1

WO2017053862A1 - Adhesion promotion in electrochemical devices

Info

Publication number: WO2017053862A1
Application number: PCT/US2016/053536
Authority: WO
Inventors: Lizhong Sun; Byung-Sung Leo Kwak
Original assignee: Applied Materials, Inc.
Priority date: 2015-09-23
Filing date: 2016-09-23
Publication date: 2017-03-30
Also published as: TW201717462A

Abstract

A thin film battery (TFB) may comprise: an adhesion promotion layer on a thin substrate with a substrate thickness in the range of 10 microns to 100 microns, the adhesion promotion layer comprising an electrically insulating material having a thickness in the range of 50 nm to 5,000 nm; a metal adhesion layer on the adhesion promotion layer; a current collector layer on the metal adhesion layer; a cathode layer on the current collector layer; an electrolyte layer on the cathode layer; and an anode layer on the electrolyte layer; wherein the device layers form a stack on the thin substrate; and wherein the adhesion promotion layer prevents cracking of the stack and delamination from the thin substrate of the stack during fabrication of the stack, including annealing of the cathode at a temperature in the range of 500 °C to 800 °C,

Description

ADHESION PROMOTION IN ELECTROCHEMICAL DEVICES

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This appl ication claims the benefit of U.S. Provisional Application No.

62/222,574 filed Sept. 23, 2015, incorporated in its entirety herein.

FIELD

[0001] Embodiments of the present disclosure relate generally to electrochem ical devices and methods of making the same, and more specifically, although not exclusively, to thin film batteries with an adhesion promotion layer deposited on the substrate - between the substrate and current collector layers.

BACKGROUND

[0002] Thin film batteries (TFBs) may comprise a thin film stack of layers including anode and cathode current collectors (ACC, CCC), a cathode (positive electrode), a solid state electrolyte, an anode (negative electrode) and encapsulation layers or packaging.

During the fabrication process of thin film batteries, one of the layers, the positive electrode

(referred to herein as the cathode), typically formed of a material such as lithium cobalt oxide

(LCO) which needs to be annealed, at relatively high temperature, to form an electrode with desirable materials properties - such as having a high percentage (greater than 90%) of high temperature phase L1C0O2 (HT-LCO). To form a robust and wel l-functioning device structure, the stress in the individual layers of the device stack and adhesion (between layers and with the substrate) must be controlled and optimized, especially as the positive electrode undergoes this relatively high temperature (within a range of 500 °C to 800 °C, for example) thermal treatment.

[0003] In addition, there is a need to improve the device metrics of which energy density is one of the key metrics. In order to increase the energy density and further improve the form factor of thin film sol id state batteries, use of thinner substrates is one of the most effective and necessary methods. However, use of thinner ( 10 microns to 100 microns thick, for example) substrates brings many chal lenges related to making devices with satisfactory operational characteristics and robustness. One of the key issues that the present inventors have observed is the poor adhesion of layers in the device stack and between stack and substrate when the device on a thin substrate is subjected to annealing as needed for proper formation of the cathode - a layer of LCO - for example. Another issue due to the use of thin substrates, which are quite flexible when handled, is that device layers, if adhesion is poor between layers or between layers and the substrate, can crack and even delaminate during the various stages of device fabrication. This cracking and delamination may be observed visually from the top side of the device, and for transparent substrates through the backside of the substrate - as discussed in more detail below. Furthermore, the cracking and delamination may reduce mechanical yield of TFBs at the end of the fabrication due to further build-up of stress with additional layers after LCO deposition and anneal. Such a build-up of stress during the fabrication step without good adhesion of the device to the substrate will create an even worse situation when the device is cycled, wherein volume changes occur in the device with Li moving back and forth between cathode and anode. Herein "mechanical yield" refers to the electrochemical cell mechanical stability on completion of fabrication, and after minimal cycling.

[0004] One example of such a thin substrate is a mica substrate, a kind of silicate

(phyllosilicate) mineral that has a layered or platy structure and can readily be divided into very thin layers - 125 to 25 microns or thinner, down to 10 microns. Mica is chemically inert, elastic, flexible, and electrically insulating. It is a good substrate to use for thin film batteries, unless high temperature processing above about 500 °C to 600 °C is needed, at which temperatures the inventors have observed a tendency for peeling and delamination of device layers from the substrate. This limits the use of mica substrates for making high quality batteries because the annealing temperature of typical cathode materials - such as LCO - may need to be greater than 600 °C, in order to obtain cathode material with purer phase and greater crystallinity (greater than 90% HT-LCO) and good battery performance. This is especially true if the LCO deposition rate is very high for cost of ownership reduction.

[0005] Another example of a thin substrate is a polycrystalline ceramic substrate such as yttrium oxide-stabilized zirconium oxide (YSZ). While these YSZ substrates can withstand much higher thermal budgets than mica for example, including annealing beyond 600 °C, the present inventors found that adhesion between the substrate and the device stack layers may also be less than satisfactory, leading to mechanical stability issues. [0006] Another example of a thin substrate is a glass substrate with a relatively high glass transition temperature - greater than the annealing temperature, for example and in some embodiments greater than 700 °C. Examples of such glasses include aluminoborosilicate glass with a glass transition temperature of 717 °C, and an alkaline earth boro-aluminosilicate with a glass transition temperature of approximately 700 °C. On these substrates, the inventors found that adhesion between the substrate and the device stack layers may also be less than satisfactory, leading to device performance and mechanical stability issues.

100071 __ .Clearly, there is aiieed for fabrication-processes-and .electrochemical device _ structures that reduce cracking and delamination of device layers during high temperature annealing (such as an LCO anneal) and thus maintain: the function and integrity of the whole electrochemical device structure (avoiding delamination of device layers by controlling stress between device layers and/or the stack of device layers and the substrate). Furthermore, there is a need for fabrication processes and electrochemical device structures that reduce cracking and delamination of device layers during high temperature annealing (such as an LCO anneal) and thus permit faster deposition rate processes for device materials such as LCO which typically require higher annealing temperature to form desirable layer qualities than follow deposition rate processes, thus permitting higher throughput and lower cost of ownership.

SUMMARY

[0008] According to some embodiments, a thin film battery (TFB) may comprise: an adhesion promotion layer on a thin substrate with a substrate thickness in the range of 10 microns to 100 microns, the adhesion promotion layer comprising an electrically insulating material, the adhesion promotion layer having a thickness in the range of 50 nm to 5,000 nm; a metal adhesion layer on the adhesion promotion layer; a current collector layer on the metal adhesion layer; a cathode layer on the current collector layer; an electrolyte layer on the cathode layer; and an anode layer on the electrolyte layer; wherein the adhesion promotion layer, the metal adhesion layer, the current collector, the cathode layer, the electrolyte layer and the anode layer form a stack on the thin substrate; and wherein the adhesion promotion layer prevents cracking of the stack and delamination from the thin substrate of the stack during fabrication of the stack, including annealing of the cathode at a temperature in the range of 500 °C to 800 °C. [0009] According to some embodiments, a method for manufacturing thin fi lm batteries may comprise: depositing an adhesion promotion layer on a thin substrate with a substrate thickness in the range of 10 microns to 1 00 microns, the adhesion promotion layer comprising an electrically insulating material, the adhesion promotion layer having a thickness in the range of 50 nm to 5,000 nm; depositing a metal adhesion layer on the adhesion promotion layer; depositing a current collector layer on the metal adhesion layer; . depositing a cathode layer on the current collector layer; annealing the cathode layer, at a temperature in the range of 500 °C to 800 °C; after the anneal ing, depositing an electrolyte layer on the cathode layer; and depositing an anode layer on the electrolyte layer; wherein the adhesion promotion layer, the metal adhesion layer, the current collector layer, the cathode layer, the electrolyte layer and the anode layer form a stack on the thin substrate; and wherein the adhesion promotion layer prevents cracking of the stack and delamination from the thin substrate of the stack during fabrication of the stack, including annealing of the cathode layer.

[0010] According to some embodiments, an apparatus for manufacturing thin film batteries may comprise: a first system for depositing an adhesion promotion layer on a thin substrate with a substrate thickness in the range of 10 microns to 100 m icrons, the adhesion promotion layer comprising an electrically insulating material, the adhesion promotion layer having a thickness in the range of 50 nm to 5,000 nm; a second system for depositing a metal adhesion layer on the adhesion promotion layer and a current collector layer on the metal adhesion layer; a third system for depositing a cathode layer on the current col lector layer; a fourth system for annealing cathode layer, at a temperature in the range of 500 °C to 800 °C; a fifth system for depositing an electrolyte layer on the cathode layer; and a sixth system for depositing an anode layer on the electrolyte layer; wherein the adhesion promotion layer, the metal adhesion layer, the current collector layer, the cathode layer, the electrolyte layer and the anode layer form a stack on the thin substrate; and wherein the adhesion promotion layer prevents cracking of the stack and delamination from the thin substrate of the stack during fabrication of the stack, including annealing of the cathode layer,

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] These and other aspects and features of the present d isclosure wil l become apparent to those ord inarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures, wherein: [0012] FIG. 1 is a cross-sectional representation of a thin film battery including an adhesion promotion layer between the substrate and adhesion and current collector layers, according to some embodiments;

[0013] FIG. 2 is a schematic illustration of a cluster tool for TFB fabrication, according to some embodiments;

[0014] FIG. 3 is a representation of a TFB fabrication system with multiple in-line tools, according to some embodiments; and

[0015] FIG. 4 is a representation of an in-line tool of FIG. 5, according to some embodiments.

DETAILED DESCRIPTION

[0016] Embodiments of the present disclosure will now be described in detail with reference to the drawings, which are provided as illustrative examples of the disclosure so as to enable those skilled in the art to practice the disclosure. Notably, the figures and examples below are not meant to limit the scope of the present disclosure to a single embodiment, but other embodiments are possible by way of interchange of some or all of the described or illustrated elements. Moreover, where certain elements of the present disclosure can be partially or fully implemented using known components, only those portions of such known components that are necessary for an understanding of the present disclosure will be described, and detailed descriptions of other portions of such known components will be omitted so as not to obscure the disclosure. In the present specification, an embodiment showing a singular component should not be considered limiting; rather, the disclosure is intended to encompass other embodiments including a plurality of the same component, and vice-versa, unless explicitly stated otherwise herein. Moreover, applicants do not intend for any term in the specification or claims to be ascribed an uncommon or special meaning unless explicitly set forth as such. Further, the present disclosure encompasses present and future known equivalents to the known components referred to herein by way of illustration.

[0017] The present disclosure describes how an adhesion promotion layer is added to the top surface of a TFB substrate prior to depositing the layers of the device on the substrate - the adhesion promotion layer having good adhesion to both the substrate and the current collector layers (both metal adhesion layer and current collector), acting as a double-sided glue layer and reducing the interdependence of the CCC adhesion layer and the substrate. This increases the freedom in material selection of TFB substrates, and facilitates increase of the energy density of TFB devices.

[0018] The adhesion promotion layer may be a thin, electrically insulating (with a resistance greater than 30 ΜΩ, for example) dielectric layer (e.g., AI2O3, Zr0₂, Si0₂, etc., including suboxides, stoichiometric and nonstoichiometric variations, and crystalline, amorphous and mixed phase versions of the same), which is able to withstand high annealing temperature and provide better adhesion and stress balance. The adhesion promotion layer is deposited between a thin substrate (e.g., mica, YSZ, and glass) and the current collector layers, the latter including a metal adhesion layer (ADL) and a metal, typically refractory, current collector. The adhesion promotion layer should have good thermal stability at temperatures higher than 700 °C and promote improved adhesion to both the substrate (mica, YSZ, and glass) and most of the current collector metal adhesion layers (e.g., Ti, Ta, TaN, etc.). The thickness of the dielectric adhesion layer is in the range from 50 nm to 5000 nm, in embodiments in the range from 50 nm to 500 nm, and in embodiments in the range from 1 00 nm to 300 nm.

[0019] FIG. 1 shows an example of a TFB device 100 according to some embodiments comprising: a substrate 1 10 (such as mica, YSZ ceramic, with 2 to 8 weight percent yttrium oxide and other minor additives and impurities, and glass), an adhesion promotion layer 120 over the top substrate surface, a metal adhesion layer 130 (e.g. Ti) and cathode current collector (CCC) 140 (e.g. Au, Pt) on the top surface of the intermixing barrier layer, a cathode 150 (a layer of LCO, for example) on the CCC, an electrolyte 160 covering the cathode and portions of the CCC, isolating the CCC from any other electrodes, an anode 1 70 (e.g. Li) on portions of the top surface of the electrolyte and the anode current collector (ACC) 180 (e.g. Au), and encapsulation layer(s) 190 covering the exposed surfaces of the anode and electrolyte and portions of the current collectors. It is noted that the adhesion layer 130 is also provided between the intermixing barrier layer and the ACC if needed, but may not be needed in all embodiments.

[0020] An example of the TFB device of FIG. 1 is described in more detail, as follows. The TFB of FIG. 1 would ordinarily be fabricated using shadow masks, and is described as such below, although it is appreciated by persons of ordinary skill in the art that a maskless fabrication process may be used to fabricate TFBs with the same materials and order of layers in the device stack, just with a slightly different layout. The thin substrate, for example a glass, ceramic, mica, metal or silicon substrate may have a thickness within the range from 10 μιη to 700 μιη, The layers deposited on the substrate are described next. The adhesion promotion layer, may comprise one or more of AI2O3, Zr0₂, Si0₂, etc., (including suboxides, stoichiometric and nonstoichiometric variations, and crystalline, amorphous and mixed phase versions of the same) with a thickness in the range of 50 nm to 5000 nm, in embodiments in the range of 50 nm to 500 nm, and in embodiments in the range of 100 nm to 300 nm, deposited on the surface of the thin substrate. An metal adhesion layer (e.g., Ti, Ta, TaN) with an area larger than that of the cathode layer with thickness ranging from 10 nm to 1000 nm is deposited on the adhesion promotion layer. A cathode current collector (e.g., Au, Pt) with an area the same as the adhesion layer with thickness ranging from 50 nm to 1000 nm is deposited on top of the metal adhesion layer. A cathode layer (e.g., LiCo0₂) with thickness ranging from 0.5 μιη to 40 μιη is deposited on top of the cathode current collector layer. The stack is thermally treated to anneal the cathode layer, as needed, before further deposition steps. A solid state electrolyte layer (e.g., LiPON) having a larger area than and extending beyond the cathode and the cathode current collector (except for the electrical contact area, where the CCC is left uncovered) with thickness ranging from 0.5 μιτι to 4 μιη is deposited on top of the interlayer. An anode current collector (e.g., Cu, Au, Pt) with no overlap with the cathode layer and the cathode current collector and with thickness ranging from 1 00 nm to 1000 nm is deposited on top of the solid state electrolyte; additionally, a metal adhesion layer may be deposited before the anode current collector, if needed, in a manner similar to that used for the cathode current collector layer. An anode (e.g., Li metal) with an area larger than that of the cathode and smaller than that of the electrolyte layer and with thickness ranging from 1 μιη to 15 μηι, overlapping partially with the anode current collector layer, is deposited on the electrolyte and a portion of the ACC. An encapsulation layer of varying functions with an area larger than that of the anode layer and smaller than that of the electrolyte layer, with thickness ranging from 400 nm to 3 μιη is deposited on top of the anode layer; the encapsulation layer can be a combination of a metal layer (e.g. Cu, Au, Pt, etc) and a dielectric layer (such as LiPON, AI2O3, Zr0₂, Si0₂, S13N4, planarizing polymer layers, etc.).

[0021] The adhesion promotion layer of FIG. 1 is incorporated in embodiments into the device stack to overcome problems due to cracking and even delamination from the substrate of device layers, as described in more detail below. To achieve good adhesion of the stack of device layers to the substrate, managing the following is needed: (1) good adhesion strength between each interface from chemical bonding and/or mechanical (roughness) bonding, (2) built-in stress within each layer designed to cancel out stress between and built-in to other layers in the stack, and (3) stress due to thermal annealing as may be required to achieve desirable cathode material properties. As such, addition of an AI2O3 adhesion promotion layer promotes better adhesion between the YSZ and adhesion promotion layer and between the adhesion promotion layer and the Ti/Pt (ADL/current collector) than observed for YSZ and Ti/Pt (ADL/current collector) deposited directly on an YSZ substrate without an AI2O3 adhesion promotion layer. This may be due to the action of the Ar/02 plasma, specifically the O2 content, generated during deposition by PVD of the AI2O3 layer, inducing a better chemical bonding at the YSZ-A1₂0₃ interface. In addition, the deposition of the Ti ADL on AI2O3 may result in the formation of Ti-0 bonds with the O in A1₂0₃ which may be stronger than the Ti-0 bonds with the O in YSZ. It is also possible that the stress in the AI2O3 layer itself may compensate the stress built up in the device stack (up to the full stack formation) and/or substrate during processing, particularly considering the stress that may be built up in the device during annealing of the cathode material due to the different thermal expansion coefficients (TEC) of the different device layers and the substrate.

[0022] Deposition of alumina films optimized for use as an adhesion promotion layer may be achieved using PVD at higher areal power densities (greater than 3.5 KW/cm², for example) in an argon/oxygen gas plasma environment. Furthermore, higher deposition power may induce better adhesion per the logic of the previous paragraph.

[0023] To demonstrate the efficacy of the adhesion promotion layer, the following experiments were conducted. As a control, the following stack (without an adhesion promotion layer) was fabricated: on a mica substrate a Ti/Au metal adhesion layer/CCC, followed by an LCO cathode, a LiPON electrolyte and a Li anode layer. The stack was annealed at 600 °C after LCO deposition and before LiPON deposition, and after Li anode layer deposition the stack showed poor adhesion to the mica substrate, resulting in significant delamination of the stack from the substrate. A second stack was fabricated: on a mica substrate coated with an alumina adhesion promotion layer, according to some embodiments, a Ti/Au metal adhesion layer/CCC, followed by an LCO cathode, a LiPON electrolyte and a Li anode layer. The stack was annealed at 600 °C after LCO deposition and after Li anode layer deposition the stack showed better adhesion to the m ica substrate than for the control. It was noted that the cracking and delamination was most evident after the Li anode deposition, due to defects being more readily visible after lithium deposition and also potentially due to a further build-up of stress with the lithium metal deposition which could lead to more cracking and delamination.

[0024] Furthermore, even better results were seen on both YSZ, with 2 to 8 weight percent yttrium oxide, and glass (an alkaline earth boro-aluminosilicate with glass transition temperature of approximately 700 °C) substrates, for which the add ition of an adhesion promotion layer appears to have eliminated all delamination - providing a 100% mechanical yield of TFB cells. The addition of the adhesion promotion layer has been found to improve the mechanical yield of TFBs fabricated on all substrates tested by the inventors, including mica, YSZ and glass.

[0025] Whi le the demonstration of an adhesion promotion layer was with a PVD (physical vapor deposition) sputtered interlayer, it is expected that the concept is agnostic to the method of deposition - for example the deposition technique for the adhesion promotion layer may be any deposition technique that is capable of providing the desired composition, phase and crystallinity, and may include deposition techniques such as PVD, reactive sputtering, non-reactive sputtering, F (radio frequency) sputtering, multi-frequency sputtering, evaporation, CVD (chem ical vapor deposition), ALD (atom ic layer deposition), etc.. The deposition method can also be non-vacuum based, such as plasma spray, spray pyrolysis, slot die coating, screen printing, etc.

[0026] Although embodiments of the present disclosure have been particu larly descri bed with reference to planar TFBs (with ACC and CCC in the same plane), the principles and teaching of the present disclosure may be applied to other TFB configurations, including a vertical stack configuration where ACC and CCC are parallel, but on opposite sides of the stack.

[0027] FIG. 2 is a schematic i llustration of a processing system 500 for fabricating a TFB, according to some embodiments. The processing system 500 includes a standard mechanical interface (SMIF) 501 to a cluster tool 502 equipped with a reactive plasma clean (RPC) chamber 503 and process chambers C 1 -C4 (504, 505, 506 and 507), which may be uti lized in the process steps described above. A glovebox 508 may also be attached to the cluster tool, The glovebox can store substrates in an inert environment (for example, under a noble gas such as He, Ne or Ar), which is useful after alkali metal/alkaline earth metal deposition. An ante chamber 509 to the glovebox may also be used if needed - the ante chamber is a gas exchange chamber (inert gas to air and vice versa) which allows substrates to be transferred in and out of the glovebox without contaminating the inert environment in the glovebox. (Note that a glovebox can be replaced with a dry room ambient of sufficiently low dew point as such is used by lithium foil manufacturers,) The chambers C 1 -C4 can be configured for process steps for manufacturing TFBs which may include, for example: deposition of an alumina adhesion promotion layer on a mica, YSZ or glass substrate, a metal adhesion layer and CCC on the adhesion promotion layer, followed by an LCO cathode on the CCC to form a stack on the substrate, annealing of the stack, etc, as described above. Examples of suitable cluster tool platforms include display cluster tools. It is to be understood that wh i le a cluster arrangement has been shown for the processing system 500, a l inear system may be uti l ized in which the processing chambers are arranged in a line without a transfer chamber so that the substrate continuously moves from one chamber to the next chamber.

[0028] FIG. 3 shows a representation of an in-line fabrication system 600 with multiple in-line tools 601 through 699, including tools 630, 640, 650, according to some embodiments. In-line tools may include tools for depositing all the layers of a TFB, Furthermore, the in-l ine tools may include pre- and post-cond itioning chambers. For example, tool 601 may be a pump down chamber for establishing a vacuum prior to the substrate moving through a vacuum airlock 602 into a deposition tool. Some or all of the in-line tools may be vacuum tools separated by vacuum airlocks. Note that the order of process tools and specific process tools in the process line will be determined by the particular TFB fabrication method being used, for example, as specified in the process flows described above. Furthermore, substrates may be moved through the in-line fabrication system oriented either horizontal ly or vertically.

[0029] In order to illustrate the movement of a substrate through an in-l ine fabrication system such as shown in FIG. 3, in FIG. 4 a substrate conveyer 701 is shown with only one in-l ine tool 630 in place, A substrate holder 702 containing a substrate 703 (the substrate holder is shown partially cut-away so that the substrate can be seen) is mounted on the conveyer 701 , or equivalent device, for moving the holder and substrate through the in-l ine tool 630, as indicated. An in-line platform for processing tool 630 may in some embodiments be configured for vertical substrates, and in some embodiments configured for horizontal substrates.

[0030] Some examples of apparatus for fabricating a TFB according to certain

embodiments are as follows. A first apparatus for manufacturing TFBs according to some embodiments may include: a first system for depositing an adhesion promotion layer on a thin substrate with adhesion promotion layer thickness in the range of 50 nm to 5000 nm, in embodiments in the range of 50 nm to 500 nm, and in embodiments in the range of 100 nm to 300 nm; a second system for depositing a metal adhesion layer on the adhesion promotion layer and a current collector layer on the metal adhesion layer and patterning the current collector layer to form a CCC and an ACC; a third system for depositing a cathode layer - such as an LCO layer - on the CCC layer to form a stack on the substrate; a fourth system to deposit an electrolyte layer on the cathode layer; a fifth system to deposit an anode - such as lithium metal - on the electrolyte layer to form a stack on the substrate; and a sixth system for annealing the cathode, at a temperature in the range of 500 °C to 800 °C, with a soak time in the range of 4 to 1 5 hours, and in embodiments in the range of 2 to 30 hours, depending on the thickness of the layer to be annealed, for example; wherein the adhesion promotion layer prevents cracking and delamination of the stack of device layers during device processing, including annealing of the cathode at a temperature in the range of 500 °C to 800 °C, Furthermore, the apparatus may include a seventh system for depositing an encapsulation layer over the stack. Furthermore, in some embodiments the second system may be two or more separate systems - for example, one for deposition of the metal adhesion layer, a second system for deposition of the current collector layer and a third system for patterning of the current collector layer. The apparatus may also comprise systems for patterning the various layers, and in embodiments shadow masks may be used in one or more of the aforesaid deposition systems. The systems may be cluster tools, in-line tools, stand-alone tools, or a combination of one or more of the aforesaid tools. Furthermore, the systems may include some tools which are common to one or more of the other systems.

[0031] Furthermore, a second apparatus for manufacturing TFBs according to some embodiments may include: a first system for depositing an adhesion promotion layer on a thin substrate, with adhesion promotion layer thickness in the range of 50 nm to 5000 nm, in embodiments in the range of 50 nm to 500 nm, and in embodiments in the range of 1 00 nm to 300 nm; a second system for depositing a metal adhesion layer on the adhesion promotion layer and a current collector layer on the metal adhesion layer; a third system for depositing a cathode layer - such as an LCO layer - on the CCC layer; a fourth system to deposit an electrolyte layer on the cathode layer; a fifth system to deposit an anode - such as lithium metal - on the electrolyte layer; a sixth system to deposit an ACC on the anode layer to form a stack on the substrate; and a seventh system for annealing the cathode, at a temperature in the range of 500 °C to 800 °C, with a soak time in the range of 4 to 15 hours, and in embodiments in the range of 2 to 30 hours, depending on the thickness of the layer to be annealed, for example; wherein the adhesion promotion layer prevents cracking and delamination of the stack of device layers during device processing, including annealing of the cathode at a temperature in the range of 500 °C to 800 °C, Furthermore, the apparatus may include an eighth system for depositing an encapsulation layer over the stack.

Furthermore, in some embodiments the second system may be two separate systems - one for deposition of the metal adhesion layer, and a second system for deposition of the CCC. The apparatus may also comprise systems for patterning the various layers, and in embodiments shadow masks may be used in one or more of the aforesaid deposition systems. The systems may be cluster tools, in-line tools, stand-alone tools, or a combination of one or more of the aforesaid tools. Furthermore, the systems may include some tools which are common to one or more of the other systems.

[0032] Although embodiments of the present disclosure have been particularly described with reference to TFBs with LCO cathodes, the principles and teaching of the present disclosure may be applied to TFBs with other cathode materials, including LiM0₂ (M=Co, Ni, Mn, etc). Where, for example LiMnC>₂ and LiFePC^ may be annealed at a temperature in the range of 500 °C to 800 °C, with a soak time in the range of 4 to 15 hours, and in embodiments in the range of 2 to 30 hours, depending on the thickness of the layer to be annealed, for example.

[0033] Although embodiments of the present disclosure have been particularly described with reference to TFBs, the principles and teaching of the present disclosure may be applied to other electrochemical devices, including energy storage devices generally, and also to electrochromic devices.

[0034] Although embodiments of the present disclosure have been particularly described with reference to single-sided TFBs, the principles and teaching of the present disclosure may be applied to double-sided TFBs. [0035] Although embodiments of the present disclosure have been particu larly descri bed with reference to certain embodiments thereof, it shou ld be readily apparent to those of ordinary ski l l in the art that changes and modifications in the form and detai ls may be made without departing from the spirit and scope of the disclosure.

Claims

WHAT IS CLAIMED IS:

1. A thin film battery (TFB) comprising:

an adhesion promotion layer on a thin substrate with a substrate thickness in the range of 10 microns to 100 microns, said adhesion promotion layer comprising an electrically insulating material, said adhesion promotion layer having a thickness in the range of 50 nra to 5,000 nm; a metal adhesion layer on said adhesion promotion layer;

a current collector layer on said metal adhesion layer;

a cathode layer on said current collector layer;

an electrolyte layer on said cathode layer; and

an anode layer on said electrolyte layer;

wherein said adhesion promotion layer, said metal adhesion layer, said current collector, said cathode layer, said electrolyte layer and said anode layer form a stack on said thin substrate; and

wherein said adhesion promotion layer prevents cracking of said stack and delamination from said thin substrate of said stack during fabrication of said stack, including annealing of said cathode at a temperature in the range of 500 °C to 800 °C.

2. The TFB of claim 1 , wherein said thin substrate is a mica substrate.

3. The TFB of claim 1 , wherein said thin substrate is a yttrium oxide-stabilized zirconium oxide substrate.

4. The TFB of claim 1 , wherein said thin substrate is a glass substrate, said glass substrate being formed of glass with a glass transition temperature of greater than 700 °C, and wherein the annealing temperature of said cathode layer is approximately 600 °C.

5. The TFB of claim 1, wherein said cathode layer is a lithium cobalt oxide (LCO) layer having greater than 90% by volume of high temperature phase LCO.

6. The TFB of claim 1 , wherein said adhesion promotion layer is an alumina layer.

7. A method for manufacturing thin film batteries comprising:

depositing an adhesion promotion layer on a thin substrate with a substrate thickness in the range of 10 microns to 100 microns, said adhesion promotion layer comprising an electrically insulating material, said adhesion promotion layer having a thickness in the range of 50 nm to 5,000 nm;

depositing a metal adhesion layer on said adhesion promotion layer

depositing a current collector layer on said metal adhesion layer;

depositing a cathode layer on said current collector layer;

annealing said cathode layer, at a temperature in the range of 500 °C to 800 °C;

after said annealing, depositing an electrolyte layer on said cathode layer; and

depositing an anode layer on said electrolyte layer;

wherein said adhesion promotion layer, said metal adhesion layer, said current collector layer, said cathode layer, said electrolyte layer and said anode layer form a stack on said thin substrate; and

wherein said adhesion promotion layer prevents cracking of said stack and delamination from said thin substrate of said stack during fabrication of said stack, including annealing of said cathode layer.

8. The method of claim 7, wherein said thin substrate is a mica substrate.

9. The method of claim 7, wherein said thin substrate is a yttrium oxide-stabilized zirconium oxide substrate.

10. The method of claim 7, wherein said thin substrate is a glass substrate, said glass substrate being formed of glass with a glass transition temperature of greater than 700 °C, and wherein the annealing temperature of said cathode layer is approximately 600 °C.

1 1. The method of claim 7, wherein said cathode layer is a lithium cobalt oxide (LCO) layer having greater than 90% by volume of high temperature phase LCO after said annealing.

12. The method of claim 7, wherein said adhesion promotion layer is an alumina layer.

13. The method of claim 12, wherein said alumina layer is deposited by physical vapor deposition at an areal power density greater than 3.5 W/cm² in an argon/oxygen gas plasma environment.

14. An apparatus for manufacturing thin film batteries comprising:

a first system for depositing an adhesion promotion layer on a thin substrate with a substrate thickness in the range of 10 microns to 100 microns, said adhesion promotion layer comprising an electrically insulating material, said adhesion promotion layer having a thickness in the range of 50 nm to 5,000 nm;

a second system for depositing a metal adhesion layer on said adhesion promotion layer and a current collector layer on said metal adhesion layer;

a third system for depositing a cathode layer on said current collector layer;

a fourth system for annealing cathode layer, at a temperature in the range of 500 °C to

800 °C;

a fifth system for depositing an electrolyte layer on said cathode layer; and

a sixth system for depositing an anode layer on said electrolyte layer;

15. The apparatus of claim 14, wherein said first system comprises a physical vapor deposition tool for deposition of an alumina adhesion promotion layer at an areal power density greater than 3.5 W/cm² in an argon/oxygen gas plasma environment.