KR20090062409A - Thin film battery having enhanced surface area of electrode and enhanced contact area between electrode and electrolyte and method for producing the same - Google Patents

Abstract

A thin film battery is provided to increase contact area between an electrode and electrolyte, to uniformly form thin films which successively are laminated on the etched surface, and to improve capacity and power density of the thin film battery. A thin film battery comprises a substrate(1); a first collector formed on the substrate; a cathode formed on the first collector; an electrolyte layer formed on the cathode; an anode formed on the electrolyte layer; and a second collector contacted with the anode. At least one of grooves having terraced both sides is formed on the surface of the substrate or the first collector. Other elements are deposited on the top of the substrate or the first collector.

Description

Thin film type battery having increased surface area of electrode and contact area between electrode and electrolyte, and method of manufacturing the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film type battery and a manufacturing method thereof, and more particularly, to a thin film type battery in which the amount of an electrode and the contact area between an electrode and an electrolyte are increased.

Thin-film batteries are known to be very safe due to the use of solid electrolytes, which have little self-discharge during non-use and there is no risk of leakage or explosion. However, in order to solve the low capacity, which is a disadvantage in the thin film battery, the thickness of the anode thin film should be increased, but there is a limit in increasing the thickness due to the PVD method such as sputtering in the manufacturing process of the thin film battery.

In particular, lithium transition metal compounds commonly known as LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , etc., must be present in the crystal phase so that efficient lithium intercalation is possible, and thus the battery performance can be exhibited as sputtering and electron beam deposition. When using a method such as vacuum thermal deposition or laser thin film deposition, the lithium transition metal compound is present in an amorphous state during initial thin film deposition, and a separate heat treatment process is required to crystallize.

However, as the thickness of the thin film increases, a process such as cracking during the heat treatment process is difficult due to an increase in the stress in the thin film, and when the battery is actually formed using such a thin film, it results in poor yield and reliability. In addition, when the thickness of the anode increases, the conductivity in the anode decreases, which causes a disadvantage in that output characteristics such as high rate discharge are degraded.

Therefore, a method for solving the above disadvantages is to increase the surface area of the substrate which is the starting material of the thin film battery and increase the amount of the anode thin film to be deposited thereon, thereby simultaneously increasing battery capacity and improving output characteristics.

As a method for increasing the surface area of the substrate, there is a method of increasing the surface area by three-dimensionally etching the surface of the substrate. The etching method is a wet method consisting of an isotropic etching using a liquid solution (Fig. 1, (b)), reactive ion etching, sputter etching, vapor phase etching (Vapor) There is a dry method (Fig. 1, (a)) consisting of anisotropic etching (Phase Etching). These etching methods also differ in their use according to their characteristics.

Dry etching has an advantage in that it has an excellent aspect ratio and can control an elaborate shape of several micrometers or less, but it has the disadvantage of using expensive dry etching equipment.

In particular, when manufacturing a thin-film battery, an anisotropic etching surface, in particular, the collector, the cathode, the solid electrolyte, and the anode must be uniformly deposited on the side of the etching surface to form a good battery without a short circuit. Existing sputtering, electron beam deposition, vacuum deposition According to physical vapor deposition (Physical Vapor Depositin), there is a problem that can not be deposited a uniform thin film on the anisotropic etching surface by the dry etching. Therefore, in this case, uniform thin film formation is possible only by chemical vapor deposition using a precursor gas. However, thin film battery manufacturing by chemical vapor deposition (CVD) requires a separate device for reprocessing the exhaust gas after the process is completed because the process is complicated and the gases used are mostly toxic.

Prior arts in this field have proposed methods of increasing the surface area of a substrate to solve the low capacity of a thin-film battery, but are simply perpendicular to the plane of the substrate by anisotropic etching by dry method with excellent aspect ratio. Since the method of forming the deeply formed irregularities, holes, and the like, when forming other components on the substrate having an enlarged surface area, a chemical vapor deposition method (CVD) is inevitably employed, which causes problems as described above. For example, US Pat. No. 6,197,450 also attempts to widen the surface area of a substrate by using a silicon wafer punched with holes having a large aspect ratio as a substrate, but the deposition of the thin film is by chemical vapor deposition (CVD).

The present invention is a method of increasing the surface area by performing anisotropic etching by the dry method on the surface of the substrate, such as physical vapor deposition (PVD) and chemical vapor deposition (DV) while sufficiently increasing the amount of the electrode and the contact area between the electrode and the electrolyte (Electrolyte). It is an object of the present invention to provide a thin film battery capable of uniformly forming thin films sequentially stacked on the etching surface by any of CVD) and a method of manufacturing the same.

The present invention provides a substrate, a first collector formed on the substrate, a cathode formed on the first collector, an electrolyte layer formed on the cathode, an anode formed on the electrolyte layer, and a second contacting the anode. In a thin film battery including a collector, one or more grooves having stepped sides are formed on a surface of the substrate or the first collector, and other components are deposited on the substrate or the first collector. One aspect of the present invention is to provide a thin film battery.

The present invention also provides a thin film battery, characterized in that the step shape is a step shape rounded by isotropic etching by a wet method.

In addition, the present invention comprises the steps of forming a first collector on the substrate; Forming a cathode on the first collector; Forming an electrolyte layer on the cathode; Forming an anode on the electrolyte layer; And forming a second collector in contact with the anode, wherein the photoresist pattern comprises at least one groove on the surface of the substrate or the first collector, the groove having stepped sides. Forming a; And performing anisotropic etching by a dry method using the photoresist pattern as a mask to form one or more grooves having stepped sides on the surface of the substrate or the first collector. It provides a method of manufacturing.

The present invention also provides a method of manufacturing a thin-film battery, characterized in that it further comprises the step of performing a round isotropic etching of the groove (groove) having a step-shaped both sides formed on the surface of the substrate or the first collector by a wet method. To provide.

According to the present invention, the physical vapor deposition and chemical vapor phase are sufficiently increased while the amount of the electrode and the contact area between the electrode and the electrolyte are sufficiently increased by performing anisotropic etching on the surface of the substrate or the first collector by a dry method to increase the surface area. In any of the deposition methods, it is possible to uniformly form thin films sequentially stacked on the etching surface, thereby improving the capacity and output density of the thin film battery very economically.

The present invention provides a substrate, a first collector formed on the substrate, a cathode formed on the first collector, an electrolyte layer formed on the cathode, an anode formed on the electrolyte layer, and a second contacting the anode. In a thin film battery including a collector, one or more grooves having stepped sides are formed on a surface of the substrate or the first collector, and physical vapor deposition is formed on the substrate or the first collector. It relates to a thin film battery characterized by depositing other components.

The thin film battery of the present invention forms one or more grooves having both sides of a step shape in the substrate or the first collector. When the first collector is formed in the first collector, the increase in the amount of the electrode and the contact area between the electrode and the electrolyte are more. Although there is an advantage that it can be formed widely, it should be taken into consideration that it is not easy to implement unless the thickness of the first collector film is more than several tens of microns.

In the present invention, the grooves having both sides of the stepped shape may have any size, number, arrangement, etc. of the grooves except for the cross-sectional shape, and are not particularly limited. For example, a stripe type, a check type, etc. are mentioned.

Since the grooves having both sides of the stepped shape are formed by forming a photoresist pattern having the grooves having both sides of the stepped shape and performing anisotropic etching by the dry method, etching can be performed simply and precisely; Despite providing the same surface area increase effect as compared with grooves having an angular U-shaped cross section, a vertical plane formed in a step shape and formed perpendicular to the plane of the substrate or the first collector is formed of several shallow layers. Therefore, even if the other components are deposited by physical vapor deposition has the advantage that it is possible to uniform deposition.

In the case of the groove having the angular U-shaped cross section mentioned above, since the vertical plane formed in the direction perpendicular to the plane of the substrate or the first collector has a deep depth, when the other components are deposited by physical vapor deposition, a uniform deposition is obtained. impossible. Therefore, there is a problem to be due to chemical vapor deposition.

The present invention also provides a thin film battery characterized by rounding a groove having both sides of a stepped shape formed on the surface of the substrate or the first collector.

Round treatment in the above can be achieved by isotropic etching by the wet method. In the case of the round treatment as described above, since the vertical plane formed in the direction perpendicular to the plane of the substrate or the first collector is significantly smaller than the step-shaped step before the round treatment, the deposition of other components by physical vapor deposition is recommended. Films of other components that are easier and more deposited are also formed more uniformly.

The invention also includes forming a first collector on a substrate; Forming a cathode on the first collector; Forming an electrolyte layer on the cathode; Forming an anode on the electrolyte layer; And forming a second collector in contact with the anode, wherein the photoresist pattern comprises at least one groove on the surface of the substrate or the first collector, the groove having stepped sides. Forming a; And performing anisotropic etching by a dry method using the photoresist pattern as a mask to form one or more grooves having stepped sides on the surface of the substrate or the first collector. It relates to a manufacturing method of.

 In the above manufacturing method, the substrate or the other components formed on the first collector having one or more grooves having both sides of the step shape may be formed by physical vapor deposition or chemical vapor deposition.

The present invention also provides

In the above manufacturing method, further comprising the step of performing a round process by performing an isotropic etching of the groove (groove) having a step-shaped both sides formed on the surface of the substrate or the first collector by a wet method. Provide a method.

When the rounding process is added as described above, since almost no vertical surface is formed in the groove in the direction perpendicular to the plane of the substrate or the first collector, physical vapor deposition of other components formed on the substrate or the first collector is performed. In this case, a more uniform film can be formed.

Forming a photoresist pattern including at least one groove (groove) having both sides of the step shape on the surface of the substrate or the first collector in the manufacturing method

Applying and drying a negative photoresist on the surface of the substrate or the first collector, and fabricating a photomask having a light shielding layer having an area corresponding to the interval of the first end (lowest end) of the grooves having stepped sides. After exposure using light, developing and drying to form a first stage; And a photomask having a light shielding layer having a width corresponding to a distance required to apply and dry a negative photoresist on the first end formed above, and to form a second end of the groove having stepped sides. Developing and drying to form a second stage; And repeating the same process as the second stage forming step according to the height of the groove.

Hereinafter, the configuration and operation of the present invention through the embodiments of the present invention will be described in detail.

2 illustrates a method of forming a groove having both sides of a stepped shape on the surface of the substrate 1 as an embodiment of the present invention.

In FIG. 2, (a) illustrates a substrate 1 in which a photoresist pattern 40 including grooves having both sides of a step shape is formed. The photoresist pattern 40 as shown in FIG. 2A can be formed using a negative photoresist composition. In the negative photoresist composition, a portion where light is not irradiated at the time of exposure is removed by development, so that if the first stage 10 is fixed by exposure, the first stage 10 is not exposed again when the second stage 20 is formed. Since the silver remains undeveloped and only the unexposed portions of the photoresist composition applied on the first end 10 are removed by development, it becomes possible to form a stepped photoresist pattern.

FIG. 2B illustrates a substrate 1 having grooves having stepped sides on its surface. The grooves having both sides of the stepped grooves may be formed on the substrate (FIG. 2A) in which the photoresist pattern 40 having the grooves having both sides of the stepped shape is formed (reactive ion etching, sputter etching). It is formed by anisotropic etching by a dry method such as (sputter etching), vapor phase etching (Vapor Phase Etching).

As already mentioned above, the stepped grooves have the same surface area increase effect as compared to the grooves having the angled U-shaped cross section (Fig. 1, (a)). Since the vertical plane formed in the shape and formed in a direction perpendicular to the plane of the substrate 1 is formed of a plurality of layers having a shallow depth, even if the other components are deposited by physical vapor deposition, uniform deposition is possible. In the case of grooves having an angular U-shaped cross section (Fig. 1, (a)), since the vertical plane formed in the direction perpendicular to the plane of the substrate 1 is deep, it is uniform when depositing other components by physical vapor deposition. Since it is impossible to deposit, there is a problem to be caused by chemical vapor deposition.

FIG. 3 illustrates a method of forming a groove having both sides of a stepped round on a surface of a substrate as an embodiment of the present invention.

Specifically, the substrate 1 (FIG. 3, (a)) in which grooves having both sides of stepped shapes are formed on the surface is processed by an isotropic etching process by a wet method, and grooves having both sides of stepped steps rounded are processed. A substrate 1 (Fig. 3, (b)) on which grooves are formed is manufactured.

As already mentioned above, when the step 52 is processed to be round 50, the physical surface is substantially reduced since the vertical plane formed perpendicular to the plane of the substrate 1 is smaller than the step before the round processing. It is easier to deposit other components by deposition and the film of the other components deposited is more uniformly formed.

4 illustrates a method of forming the photoresist pattern 40 as one embodiment of the present invention. As mentioned above, a negative type may be used as the photoresist composition, and the formation process will be described in detail as follows.

First, in FIG. 4, (a) shows a process of applying and drying a negative photoresist composition.

(b) shows a process of exposing the glass and plastic substrate 62 provided with the light shielding portion 61 as a photomask 60 to form the first end 10 of the photoresist pattern 40. In this case, the part which is not exposed by the light shielding part 61 is removed by the image development process, and the part exposed through the exposure part 63 is left as it is without melt | dissolving in a developing solution.

(c) shows the first end 10 of the photoresist pattern 40 formed by the above exposure and development. Since this part is not dissolved in the developer by exposure, it remains even during development of the forming process of the second stage 20.

(d) shows a process of applying and drying the negative type photoresist composition on top of the first end 10 formed above to form the second end 20 of the photoresist pattern 40.

(e) shows the same exposure process as above (b). After the exposure, when the developing process is performed, the portion not exposed by the light shielding unit 61 is removed by the developing process. To form. In addition, since the first stage 10 is also insoluble in the developer, it remains and forms a step shape together with the second stage 20.

(f) shows the photoresist pattern 40 composed of the first end 10 and the second end 20 formed by the above exposure and development.

(g) shows a process of applying and drying the negative photoresist composition on top of the second end 20 formed above to form the third end 30 of the photoresist pattern 40.

(h) shows the same exposure process as above (e). After the exposure, when the development process is performed, the portion not exposed by the light shielding portion 61 is removed by the development process, and the portion exposed through the exposure portion 63 remains intact in the developing solution and remains in the third stage 30. To form. In addition, since the first stage 10 and the second stage 20 already formed do not dissolve in the developer, they remain and form a stepped shape together with the third stage 20.

(i) shows the photoresist pattern 40 composed of the first end 10, the second end 20 and the third end 30 formed by the above exposure and development.

In the present invention, the stepped photoresist pattern 40 forms the number of steps 10, 20, and 30 according to the depth of the groove.

5 illustrates a method of constructing a thin film battery according to an embodiment of the present invention.

First, (a) shows a substrate 1 on which grooves having both sides of a stepped shape rounded by isotropic etching by a wet method are formed. In the present invention, any type of substrate forming a groove having both sides of a stepped round shape is not particularly limited as long as it is used in the art. Examples thereof include silicon, mica, titanium (Ti), nickel (Ni), stainless steel (SUS), alumina (Al ₂ O ₃ ), and the like.

(b) shows a step of forming the first collector 100 on the substrate. The first collector-forming material can also be used without particular limitation as long as it is used in the art, and examples thereof include Pt or Au. The first collector 100 may be deposited in a shape including a groove by physical vapor deposition. Here, an adhesive layer (not shown) may be further included to improve adhesion between the substrate 1 and the first collector 100. The adhesive layer may include any one metal of Al, Ti, Co, Cr, Nb, Ta, and W, or may be formed of an indium tin oxide (ITO) layer.

(c) illustrates a process of forming the cathode 200 on the first collector 100. The cathode forming material 200 may also be used without particular limitation as long as it is used in the art, and examples thereof include lithium transition metals such as LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , and metal oxides such as V ₂ O ₅ . The cathode 200 may be deposited in a shape including a groove by physical vapor deposition.

(d) illustrates a process of forming the electrolyte layer 300 on the cathode 200. The material for forming the electrolyte layer 300 may also be used without particular limitation as long as it is used in this field. For example, an inorganic solid electrolyte or a polymer electrolyte such as LiPON may be used. The electrolyte layer 300 may also be deposited in a shape including a groove by physical vapor deposition.

(e) illustrates a process of forming the anode 400 on the electrolyte layer 300. The anode forming material may be used without particular limitation as long as it is used in this field, and examples thereof include Li, Sn, and Si-based alloys. The anode 400 may also be deposited in a shape including a groove by physical vapor deposition.

After forming the anode 400, a second collector may be formed through a planarization process. In this case, the second collector may be formed immediately without the planarization process. The protective film process may be performed before forming the second collector. In this case, the anode 400 itself is used as the second collector, or a second collector is formed on the side of the battery to connect the anode 400 and the second collector.

1 shows a comparison of (a) anisotropic etching by the dry method and (b) isotropic etching by the wet method.

2 illustrates a method of forming a groove having both sides of a stepped shape on the surface of the substrate 1 as an embodiment of the present invention.

(a): Substrate 1 on which photoresist pattern 40 including grooves having both sides of stepped shape is formed

(b): substrate (1) having grooves having stepped sides on its surface

FIG. 3 illustrates a method of forming a groove having both sides of a step shape rounded by isotropic etching by a wet method on the surface of the substrate 1 as an embodiment of the present invention.

(a): substrate 1 in which grooves are formed on the surface of which grooves have stepped sides

(b): substrate (1) having grooves having stepped both sides rounded by isotropic etching by a wet method on a surface thereof (1)

4 illustrates a method of forming a photoresist pattern 40 on a substrate as one embodiment of the invention.

5 illustrates a method of constructing a thin film battery according to an embodiment of the present invention in order.

* Description of Drawing Symbols *

1: substrate 10: first stage of stepped photoresist pattern

20: second step of stepped photoresist pattern

30: third step of stepped photoresist pattern

40: photoresist pattern

50: cross-sectional shape of stepped round shape

51: an etching portion etched by wet etching

52: cross section of stepped shape

60: photomask 61: light shield

62: glass plate 63: light transmitting part

100: first collector 200: cathode

300: electrolyte layer 400: anode

Claims (11)

A substrate, a first collector formed on the substrate, a cathode formed on the first collector, an electrolyte layer formed on the cathode, an anode formed on the electrolyte layer, and a second collector in contact with the anode In the thin film battery constituted by And at least one groove having stepped sides on the surface of the substrate or the first collector and depositing other components on the substrate or the first collector. The thin film battery according to claim 1, wherein the step shape is a step shape rounded by isotropic etching by a wet method. The thin film battery according to claim 1 or 2, wherein grooves having both sides of the step shape are formed in a stripe type or a check type on a surface of the substrate or the first collector. The thin film battery according to claim 1 or 2, wherein other components are deposited on top of the substrate or the first collector by physical vapor deposition. The thin film type battery of claim 1, wherein an adhesion increasing layer is formed between the substrate and the first collector. Forming a first collector on the substrate; Forming a cathode on the first collector; Forming an electrolyte layer on the cathode, Forming an anode on the electrolyte layer, and In the manufacturing method of a thin film battery comprising the step of forming a second collector in contact with the anode, Forming a photoresist pattern on the substrate or on the surface of the first collector, the photoresist pattern including one or more grooves having stepped sides; And performing anisotropic etching by a dry method using the photoresist pattern as a mask to form one or more grooves having stepped sides on the surface of the substrate or the first collector. Manufacturing method. The thin film type as claimed in claim 6, wherein the substrate having one or more grooves having both sides of the step shape or other components formed on the first collector are formed by physical vapor deposition or chemical vapor deposition. Method for producing a battery. The method of claim 6, further comprising rounding a groove having both sides of a stepped shape formed on a surface of the substrate or the first collector by performing an isotropic etching by a wet method. . The thin film battery according to claim 8, wherein the substrate having at least one groove having both sides of the stepped round shape or other components formed on the first collector are formed by physical vapor deposition. Manufacturing method. The method of claim 6, wherein the forming of the photoresist pattern on the surface of the substrate or the first collector comprises one or more grooves having stepped sides. Negative photoresist is applied and dried on the surface of the substrate or the first collector, and a photomask having a light shielding layer having an area corresponding to the interval of the first end (lowest end) of the groove having stepped both sides is fabricated and exposed. Developing and drying to form a first stage; And The photomask is formed by applying and drying a negative photoresist on the first end formed above, and forming a photomask in which a light shielding layer having an area corresponding to a distance required to form a second end of the groove having stepped sides is formed. Developing and drying to form a second stage; And And repeating the same process as the second stage forming step according to the height of the groove. The method of claim 6, wherein forming the first collector on the substrate comprises forming an adhesion increasing layer between the substrate and the first collector.

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