Patent Application
20220209214
One embodiment of the present invention relates to an object, a method, or a manufacturing method. Alternatively, the present invention relates to a process, a machine, manufacture, or a composition (composition of matter). One embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a lighting device, an electronic device, or a manufacturing method thereof. In particular, one embodiment of the present invention relates to a method for manufacturing a power storage device and a manufacturing apparatus therefor.
Note that electronic devices in this specification generally mean devices including power storage devices, and electro-optical devices including power storage devices, information terminal devices including power storage devices, and the like are all electronic devices.
Electronic devices carried around by users and electronic devices worn by users have been actively developed.
Electronic devices carried around by users and electronic devices worn by users operate using primary batteries or secondary batteries, which are examples of power storage devices, as power sources. It is desired that electronic devices carried around by users be used for a long time; thus, a high-capacity secondary battery is used. Since high-capacity secondary batteries are large in size, there is a problem in that their incorporation in electronic devices increases the weight of the electronic devices. In view of the problem, development of small or thin high-capacity secondary batteries that can be incorporated in portable electronic devices is being pursued.
A lithium-ion secondary battery using an electrolyte solution such as an organic solvent as a transmission medium for lithium ions serving as carrier ions is widely used. However, a secondary battery using liquid has problems of the operable temperature range, decomposition reaction of an electrolyte solution by a potential to be used, and liquid leakage to the outside of the secondary battery since the secondary battery uses liquid. In addition, a secondary battery using an electrolyte solution has a risk of ignition due to liquid leakage.
A fuel battery is a secondary battery using no liquid; however, noble metals are used for the electrodes, and a material of a solid electrolyte is also expensive.
In addition, as a secondary battery using no liquid, a power storage device using a solid electrolyte, which is called a solid-state battery, is known. For example, Patent Document 1 is disclosed.
Patent Document 1 discloses an example in which a lithium cobalt oxide film is formed over a positive electrode current collector by a sputtering method.
An object is to achieve a manufacturing apparatus that can fully automate the manufacturing of a solid-state secondary battery. Another object is to achieve a manufacturing apparatus that can manufacture a solid-state secondary battery in a short time. Another object is to achieve a manufacturing apparatus that can manufacture a solid-state secondary battery with high yield.
Another object is to provide a method for manufacturing a solid-state secondary battery without exposure to the air.
A structure of a manufacturing apparatus disclosed in this specification is a manufacturing apparatus for a solid-state secondary battery which includes a mask alignment chamber, a first transfer chamber connected to the mask alignment chamber, a second transfer chamber connected to the first transfer chamber, a first film formation chamber connected to the second transfer chamber, a third transfer chamber connected to the first transfer chamber, and a second film formation chamber connected to the third transfer chamber. In the first film formation chamber, a positive electrode active material layer or a negative electrode active material layer are formed by a sputtering method. In the second film formation chamber, a solid electrolyte layer is formed by co-evaporation of an organic complex of lithium and SiOx (0<X≤2). A substrate is transferred between the mask alignment chamber and the first film formation chamber and between the mask alignment chamber and the second film formation chamber without being exposed to the air.
In the above-described structure, a structure further including a heating chamber connected to the second transfer chamber may be employed. The heating chamber is preferably kept at a pressure lower than an atmospheric pressure (a reduced pressure atmosphere) by an exhaust mechanism before and after heat treatment. With a higher degree of vacuum, water or the like adsorbed on a surface of an insulating film can be released more efficiently. For example, the pressure in the chamber for the heat treatment when the substrate is inserted is higher than or equal to 1×10−7 Pa and lower than or equal to 1×10−3 Pa, preferably higher than or equal to 1×10−6 Pa and lower than or equal to 1×10−4 Pa.
With the above-described structure, the cleanliness of the film formation chambers and the transfer chambers can be maintained, whereby a solid-state secondary battery having favorable characteristics can be manufactured.
In the above-described first film formation chamber, the back pressure (total pressure) is set to lower than or equal to 1×10−4 Pa, preferably lower than or equal to 3×10−5 Pa, further preferably lower than or equal to 1×10−5 Pa by an exhaust mechanism. In the above-described first film formation chamber, the partial pressure of a gas molecule (atom) having a mass-to-charge ratio (m/z) of 18 is lower than or equal to 3×10−5 Pa, preferably lower than or equal to 1×10−5 Pa, further preferably lower than or equal to 3×10−6 Pa. Moreover, in the above-described first film formation chamber, the partial pressure of a gas molecule (atom) having a mass-to-charge ratio (m/z) of 28 is lower than or equal to 3×10−5 Pa, preferably lower than or equal to 1×10−5 Pa, further preferably lower than or equal to 3×10−6 Pa. Furthermore, in the above-described first film formation chamber, the partial pressure of a gas molecule (atom) having a mass-to-charge ratio (m/z) of 44 is lower than or equal to 3×10−5 Pa, preferably lower than or equal to 1×10−5 Pa, further preferably lower than or equal to 3×10−6 Pa.
Note that the total pressure and the partial pressure in a vacuum chamber such as the first film formation chamber can be measured using a mass analyzer. For example, Qulee CGM-051, a quadrupole mass analyzer (also referred to as Q-mass) produced by ULVAC, Inc. can be used.
Furthermore, in the above-described structure, the transfer chambers may have a structure where exhaust is performed from an atmospheric pressure to a low vacuum or a medium vacuum (approximately several hundreds of Pa to 0.1 Pa) using a vacuum pump and then a valve is switched to perform exhaust from the medium vacuum to a high vacuum or an ultra-high vacuum (approximately 0.1 Pa to 1×10−7 Pa) using a cryopump.
Furthermore, a method for manufacturing a solid-state secondary battery is also one embodiment of the invention disclosed in this specification and includes forming a first conductive layer over and in contact with an insulating surface, forming a negative electrode active material layer over the first conductive layer, forming a solid electrolyte layer over the negative electrode active material layer by co-evaporation of an organic complex of lithium and SiOx (0<X≤2), forming a first positive electrode active material layer over the solid electrolyte layer, forming a second conductive layer over and in contact with the insulating surface and over the first positive electrode active material layer, and forming a second positive electrode active material layer over the second conductive layer. The solid electrolyte layer is in contact with a side surface of the negative electrode active material layer, the second conductive layer is in contact with a side surface of part of the solid electrolyte layer, and the first positive electrode active material layer and the second positive electrode active material layer do not overlap with each other.
When the same sputtering target is used for the first positive electrode active material layer and the second positive electrode active material layer in the above-described manufacturing method, the manufacturing cost can be reduced.
When the same sputtering target is used for the first conductive layer and the second conductive layer in the above-described manufacturing method, the manufacturing cost can be reduced.
In the above-described structure, the organic complex of lithium is any of an alkali metal, an alkaline earth metal, an organic complex of an alkali metal or an alkaline earth metal, and a compound thereof; and Li, Li2O, or the like can be given for example. The organic complex of lithium is particularly preferable, and 8-hydroxyquinolinato-lithium (abbreviation: Liq), which has favorable characteristics, is especially preferable. As another organic material co-evaporated with SiOx (0<X≤2), dilithium phthalocyanine (phthalocyanine dilithium), lithium 2-(2-pyridyl)phenolate (abbreviation: Lipp), or lithium 2-(2′,2″-bipyridin-6′-yl)phenolate (abbreviation: Libpp) can be used.
A solid-state secondary battery is manufactured in an environment which impurities are difficult to enter without exposure to the air, so that a solid-state secondary battery having favorable characteristics can be manufactured.
Embodiments of the present invention are described in detail below with reference to the drawings. Note that the present invention is not limited to the following description, and it is readily understood by those skilled in the art that modes and details of the present invention can be modified in various ways. In addition, the present invention should not be construed as being limited to the description of the embodiments below.
In this embodiment, an example of a multi-chamber manufacturing apparatus that can fully automate the manufacturing of a first electrode to a second electrode of a secondary battery is illustrated in
The mask alignment chamber 91 includes at least a stage 51 and a substrate transfer mechanism 52.
The first transfer chamber 71 includes a substrate cassette elevation mechanism, the second transfer chamber 72 includes a substrate transfer mechanism 53, and the third transfer chamber includes a substrate transfer mechanism 54.
The first film formation chamber 92, the second film formation chamber 74, the second material supply chamber 94, the first material supply chamber 95, the third material supply chamber 96, the mask alignment chamber 91, the first transfer chamber 71, the second transfer chamber 72, and the third transfer chamber 73 are connected to their respective exhaust mechanisms. As the exhaust mechanisms, exhaust devices appropriate for the uses of the chambers are selected; for example, an exhaust mechanism including a pump having an adsorption unit, such as a cryopump, a sputtering ion pump, or a titanium sublimation pump, an exhaust mechanism including a turbo molecular pump provided with a cold trap, and the like can be given.
Procedures for forming films over a substrate are as follows. A substrate 50 or a substrate cassette is set in the load lock chamber 70 and transferred to the mask alignment chamber 91 by the substrate transfer mechanism 52. In the mask alignment chamber 91, a mask to be used is picked up from a plurality of masks set in advance, and positional alignment with the substrate is performed over the stage 51. After the positional alignment is finished, the gate 80 is opened and a transfer to the first transfer chamber 71 is performed by the substrate transfer mechanism 52. The substrate is transferred to the first transfer chamber 71, the gate 81 is opened, and a transfer to the second transfer chamber 72 is performed by the substrate transfer mechanism 53.
The first film formation chamber 92 provided next to the second transfer chamber 72 with the gate 82 therebetween is a sputtering chamber. The sputtering chamber has a mechanism capable of applying a voltage to a sputtering target with a power supply that is switched between an RF power supply and a pulsed DC power supply. Two or three kinds of sputtering targets can be set. In this embodiment, a single crystal silicon target, a sputtering target whose main component is lithium cobalt oxide (LiCoO2), and a titanium target are set. A substrate heating mechanism can be provided in the first film formation chamber 92 to perform film formation under heating conditions at a heater temperature of 700° C.
By a sputtering method using a single crystal silicon target, a negative electrode active material layer can be formed. In a negative electrode, an SiOx film formed by a reactive sputtering method using an Ar gas and an O2 gas may also be used as a negative electrode active material layer. It is also possible to use a silicon nitride film formed by a reactive sputtering method using an Ar gas and an N2 gas as a sealing film. Furthermore, a positive electrode active material layer can be formed by a sputtering method using a sputtering target whose main component is lithium cobalt oxide (LiCoO2). By a sputtering method using a titanium target, a conductive film serving as a current collector can be formed. A titanium nitride film formed by a reactive sputtering method using an Ar gas and an N2 gas can be used as a layer for preventing diffusion between a current collector layer and an active material layer.
In the case of forming a positive electrode active material layer, the mask and the substrate which are in the overlapping state are transferred from the second transfer chamber 72 to the first film formation chamber 92 by the substrate transfer mechanism 53, the gate 82 is closed, and film formation is performed by a sputtering method. After the film formation is finished, the gate 82 and the gate 83 are opened, a transfer to the heating chamber 93 is performed, the gate 83 is closed, and then heating can be performed. For heat treatment in the heating chamber 93, an RTA (Rapid Thermal Anneal) apparatus, a resistance heating furnace, or a microwave heating apparatus can be used. As the RTA apparatus, a GRTA (Gas Rapid Thermal Anneal) apparatus or an LRTA (Lamp Rapid Thermal Anneal) apparatus can be used. The heat treatment in the heating chamber 93 can be performed in an atmosphere of nitrogen, oxygen, a rare gas, or dry air. In addition, heating time is longer than or equal to 1 minute and shorter than or equal to 24 hours.
After the film formation or the heat treatment is finished, the substrate and the mask are transferred back to the mask alignment chamber 91, and positional alignment for a new mask is performed. After the positional alignment, the substrate and the mask are transferred to the first transfer chamber 71 by the substrate transfer mechanism 52. The substrate is carried by the elevation mechanism of the first transfer chamber 71, the gate 84 is opened, and a transfer to the third transfer chamber 73 is performed by the substrate transfer mechanism 54.
In the second film formation chamber 74 connected to the third transfer chamber 73 with the gate 85 therebetween, film formation by evaporation is performed.
Furthermore, the second film formation chamber 74 is connected to the second material supply chamber 94 with the gate 86 therebetween. The second film formation chamber 74 is connected to the first material supply chamber 95 with the gate 88 therebetween. The second film formation chamber 74 is connected to the third material supply chamber 96 with the gate 87 therebetween. Accordingly, the second film formation chamber 74 is capable of three-source co-evaporation.
Procedures for performing evaporation are as follows. The substrate is set on a substrate holding portion 45. The substrate holding portion 45 is connected to a rotation mechanism 65. A first evaporation material 55 is heated to some extent in the first material supply chamber 95, and when the evaporation rate is stabilized, the gate 88 is opened, and an arm 62 is extended to move the evaporation source 56 to a position under the substrate. The evaporation source 56 is composed of the first evaporation material 55, a heater 57, and a container in which the first evaporation material 55 is stored. Furthermore, a second evaporation material is also heated to some extent in the second material supply chamber 94, and when the evaporation rate is stabilized, the gate 86 is opened and an arm 61 is extended to move the evaporation source to a position under the substrate.
Then, a shutter 68 and a shutter 69 for evaporation sources are opened and co-evaporation is performed. The rotation mechanism 65 is rotated during evaporation to increase the uniformity in the film thickness. After the evaporation is finished, the substrate is transferred to the mask alignment chamber 91 through the same route. In the case of taking out the substrate from the manufacturing apparatus, the substrate is transferred from the mask alignment chamber 91 to the load lock chamber 70 and then taken out.
Furthermore,
Moreover, the second film formation chamber 74 may be provided with an imaging unit 63 such as a CCD camera. With the imaging unit 63, the position of the substrate 50 can be checked.
Furthermore, in the second film formation chamber 74, the thickness of a film formed on a substrate surface can be estimated from a result of measurement with a film thickness measurement mechanism 67. The film thickness measurement mechanism 67 may be provided with a crystal oscillator, for example.
Note that in order to control vapor deposition of vaporized evaporation materials, the shutter 68, which overlaps with the substrate, and the shutter 69 for evaporation sources, which overlaps with the evaporation source 56 and the evaporation boat 58, are provided until the vaporizing rate of the evaporation materials is stabilized.
Although an example of resistance heating evaporation is shown for the evaporation source 56, EB (Electron Beam) evaporation may also be employed. Although an example using a crucible as the container of the evaporation source 56 is illustrated, an evaporation boat may be used as well. An organic material, which is the first evaporation material 55, is put in the crucible heated by the heater 57. In the case where pellets or particles of SiO or the like are used as the evaporation material, the evaporation boat 58 is used. The evaporation boat 58 consists of three parts, in which a member having a concave portion, a middle lid with two holes, and a top lid with a hole are overlapped. Note that the middle lid may be removed to perform evaporation. The evaporation boat 58 serves as resistance by being energized and the evaporation boat is heated by itself.
Although an example of a multi-chamber apparatus is described in this embodiment, without particular limitation, the manufacturing apparatus may be of an in-line type.
An example of manufacturing a secondary battery with the evaporation apparatus illustrated in
As illustrated in
These films can each be formed using a metal mask. By using the same metal mask for the negative electrode current collector 203 and the negative electrode active material layer 205 and using the same metal mask for the positive electrode current collector 201 and the positive electrode active material layer 204, a secondary battery can be manufactured with four different metal masks.
First, the substrate 50 is set in the load lock chamber 70 illustrated in
Examples of the substrate 50 include a quartz substrate, a glass substrate, and a plastic substrate which have an insulating surface. Alternatively, a semiconductor substrate having an insulating surface can be used. A circuit such as a semiconductor element may be formed in advance on the semiconductor substrate and electrically connected to the secondary battery which is formed later.
After film formation of the negative electrode current collector 203 and the negative electrode active material layer 205 is finished, a transfer back to the mask alignment chamber 91 is performed, and positional alignment with a second metal mask is performed. Then, a transfer to the second film formation chamber 74 is performed through the transfer chamber 71 and the transfer chamber 73, and the solid electrolyte layer 202 is selectively formed by an evaporation method.
In the second film formation chamber 74, the solid electrolyte layer 202 is formed by co-evaporation of a Si powder (e.g., SiO, SiO2, a mixture of SiO and SiO2) and a Liq powder. Liq is an organic complex of lithium and refers to 8-hydroxyquinolinato-lithium. Note that a resistance heating source or an electron beam evaporation source is used for the co-evaporation. Note that without limitation to a Si powder (SiO), one with a pellet shape or a particle shape may be used.
After film formation of the solid electrolyte layer 202 is finished, a transfer back to the mask alignment chamber 91 is performed, and positional alignment with a third metal mask is performed. Then, a transfer to the first film formation chamber 92 is performed through the transfer chamber 71 and the transfer chamber 72, and a LiCoO2 film that is the positive electrode active material layer 204 and a titanium film that is the positive electrode current collector 201 are selectively formed by a sputtering method.
After film formation of the positive electrode active material layer 204 and the positive electrode current collector 201 is finished, a transfer back to the mask alignment chamber 91 is performed, and positional alignment with a fourth metal mask is performed. Then, a transfer to the first film formation chamber 92 is performed through the transfer chamber 71 and the transfer chamber 72, and a silicon nitride film (also referred to as a SiN film) serving as the protective layer 206 is selectively formed by a sputtering method with a single crystal silicon target in a nitrogen atmosphere.
As illustrated in
After film formation of the protective layer 206 is finished, a transfer back to the mask alignment chamber 91 and further to the load lock chamber 70 is performed, and then the substrate on which the secondary battery is formed is taken out.
A thin-film-type solid-state secondary battery illustrated in
Furthermore, when solid-state secondary batteries are stacked, the capacity can be increased, and thin-film-type solid-state secondary batteries connected in parallel can be manufactured. In the case of stacking solid-state secondary batteries, a positive electrode active material layer is formed in contact with both surfaces of a positive electrode, and a negative electrode active material layer is formed in contact with both surfaces of a negative electrode.
Solid-state secondary batteries can be connected in series in order to increase the output voltage of the solid-state secondary batteries. Although the example of the single-layer cell is described in Embodiment 1, an example of manufacturing solid-state secondary batteries connected in series is described in this embodiment.
Then, a second positive electrode active material layer is formed over a region which is in the positive electrode current collector 201 and does not overlap with a first positive electrode active material layer. Then, a second solid electrolyte layer 212 is formed, and a second negative electrode active material layer and a second negative electrode current collector 213 are formed thereover. Lastly, the protective layer 206 is formed as illustrated in
A plurality of thin-film-type solid-state secondary batteries connected in series can be manufactured without exposure to the air by using the manufacturing apparatus illustrated in
An example of the single-layer cell is described in Embodiment 1, whereas an example of a multi-layer cell is described in this embodiment.
A first cell is formed in such a manner that the positive electrode current collector 201 is formed over the substrate 50, and the positive electrode active material layer 204, the solid electrolyte layer 202, the negative electrode active material layer 205, and the negative electrode current collector 203 are sequentially formed over the positive electrode current collector 201.
Furthermore, a second cell is formed in such a manner that a second negative electrode active material layer, a second solid electrolyte layer, a second positive electrode active material layer, and a second positive electrode are sequentially formed over the negative electrode current collector 203.
Moreover, a third cell is formed in such a manner that a third positive electrode active material layer, a third solid electrolyte layer, a third negative electrode active material layer, and a third negative electrode are sequentially formed over the second positive electrode.
Lastly, the protective layer 206 is formed in
Note that the solid electrolyte layer 202, the second solid electrolyte layer, the third solid electrolyte layer are preferably formed using the same material in order to reduce the manufacturing cost.
In
A multi-layer cell of a thin-film-type solid-state secondary battery can be manufactured without exposure to the air by using the manufacturing apparatus illustrated in
This embodiment can be freely combined with Embodiment 1 or Embodiment 2.
In this embodiment, examples of electronic devices using thin-film-type secondary batteries are described with reference to
An active matrix display device may be provided instead of the photograph 3003. As examples of the active matrix display device, a reflective liquid crystal display device, an organic EL display device, electronic paper, or the like can be given. An image (a moving image or a still image) or time can be displayed on the active matrix display device. Electric power for the active matrix display device can be supplied from the thin-film-type secondary battery 3001.
A plastic substrate is used for the card including an IC, and thus an organic EL display device using a flexible substrate is preferable.
Instead of the photograph 3003, a solar cell may be provided. When irradiation with external light is performed, light can be absorbed to generate electric power, and the thin-film-type secondary battery 3001 can be charged with the electric power.
Without limitation to the card including an IC, the thin-film-type secondary battery can be used for a power source of an in-vehicle wireless sensor, a secondary battery for a MEMS device, or the like.
For example, a secondary battery can be incorporated in a glasses-type device 400 as illustrated in
Furthermore, the secondary battery can be incorporated in a headset-type device 401. The headset-type device 401 includes at least a microphone portion 401a, a flexible pipe 401b, and an earphone portion 401c. The secondary battery can be provided in the flexible pipe 401b or the earphone portion 401c. The thin-film-type secondary battery described in Embodiment 1 may be included, and thus a structure that can support space saving due to a reduction in the size of a housing can be achieved.
The secondary battery can also be incorporated in a device 402 that can be directly attached to a human body. A secondary battery 402b can be provided in a thin housing 402a of the device 402. The thin-film-type secondary battery described in Embodiment 1 may be included, and thus a structure that can support space saving due to a reduction in the size of a housing can be achieved.
The secondary battery can also be incorporated in a device 403 that can be attached to clothing. A secondary battery 403b can be provided in a thin housing 403a of the device 403. The thin-film-type secondary battery described in Embodiment 1 may be included, and thus a structure that can support space saving due to a reduction in the size of a housing can be achieved.
Furthermore, the secondary battery can be incorporated in a belt-type device 406. The belt-type device 406 includes a belt portion 406a and a wireless power feeding and receiving portion 406b, and the secondary battery can be incorporated in the belt portion 406a. The thin-film-type secondary battery described in Embodiment 1 may be included, and thus a structure that can support space saving due to a reduction in the size of a housing can be achieved.
The secondary battery can also be incorporated in a watch-type device 405. The watch-type device 405 includes a display portion 405a and a belt portion 405b, and the secondary battery can be provided in the display portion 405a or the belt portion 405b. The thin-film-type secondary battery described in Embodiment 1 may be included, and thus a structure that can support space saving due to a reduction in the size of a housing can be achieved.
The display portion 405a can display various kinds of information such as reception information of an e-mail or an incoming call in addition to time.
Since the watch-type device 405 is a type of wearable device that is directly wrapped around an arm, a sensor that measures pulse, blood pressure, or the like of a user can be incorporated therein. Data on the exercise quantity and health of the user can be stored and used for health maintenance.
The watch-type device 405 illustrated in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-087082 | Apr 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/053579 | 4/16/2020 | WO | 00 |
