KR20160084510A - Method for forming thick coating layer having improved surface roughness - Google Patents

Abstract

The present invention relates to a method to coat a thick film having improved surface roughness comprising: (a) a step of forming a first coating layer with aerosol deposition (AD) on a substrate; and a step of forming a second coating layer with chemical solution deposition (CSD) on the first coating layer. According to the present invention, the coating layer is additionally formed on an upper surface of the coating layer formed with the aerosol deposition (AD) through the chemical solution deposition (CSD) such as a sol-gel process, and to improve a uniformity of thickness of the coating layer; thereby obtaining a thick coating layer having uniform properties irrespective of positions.

Description

TECHNICAL FIELD [0001] The present invention relates to a thick film coating method having improved surface roughness,

The present invention relates to a thick film coating method, and more particularly, to a thick film coating method with improved surface roughness.

The ceramic coating is used to form a functional layer having a thickness of several nanometers to several tens of micrometers on the surface of a base material by using a ceramic material. The 'Aerosol Deposition method', which is also known as a room temperature spraying process, AD) 'is a technology for forming a ceramic coating layer on a substrate surface by injecting a fine ceramic powder into a carrier gas and spraying it on a substrate placed in a vacuum chamber. It is developed in Japan and its application fields are piezoelectric, dielectric, biomedical, Application of various functionalities such as materials and coating method of structural ceramics is expanding.

Compared to other thin film and thick film manufacturing processes, this AD process is capable of 1) coating a dense, crack-free coating layer at room temperature at a rate of more than 30 μm per minute, and 2) ceramic coatings on various substrates such as metals / ceramics / (3) control of the thickness of the coating layer (1 탆 to 900 탆) and easy control of the stoichiometric ratio, and in particular, a large-sized ceramic thick-film coating layer having a dense structure can be formed at room temperature The point is different from other coating methods.

However, as the raw material powder used in the AD process generally uses a fine powder having a size of several hundreds nm to several micrometers, the coagulation phenomenon of the powder tends to occur during the coating process, and the surface roughness of the formed coating layer Thereby making it difficult to obtain a coating layer having uniform physical properties irrespective of its position. The above problem is further exacerbated when a thick coat layer is desired to be obtained.

Korea Patent No. 10-2011-0125456 (published on November 21, 2011) Korean Patent Publication No. 10-2010-0128870 (published on December 12, 2010) Korea Patent Publication: 10-2002-0011692 (Publication date: 2003.09.13) Korea Patent Publication: 10-2009-0063541 (Publication date: Jun. 18, 2009)

DISCLOSURE Technical Problem The present invention has been devised to solve the problems as described above, and it is an object of the present invention to provide a method for producing a coating layer by aerosol deposition and then forming a coating layer by a chemical solution deposition method such as a sol- The present invention also provides a method for producing a thick film having uniform physical properties regardless of its position by improving the film thickness.

In order to solve the above-mentioned problems, the present invention provides a method of manufacturing a semiconductor device, comprising: (a) forming a first coating layer on an substrate by aerosol deposition (AD); And (b) forming a second coating layer by chemical solution deposition (CSD) on the first coating layer.

The step (a) may further comprise: (a-1) preparing at least one raw material powder, mixing, calcining and milling the powder to prepare a powder; And (a-2) forming a first coating layer on the substrate with an aerosol deposition using the prepared powder.

Further, after the step (a-2) is performed, a step of heat-treating the first coating layer (a-3) is further performed.

Also, the step (b) is performed by a sol-gel process.

The step (b) may further comprise: (b-1) preparing a sol solution containing a precursor compound; (b-2) applying the sol solution onto the first coating layer; (b-3) drying the applied coating layer; And (b-4) heat-treating the dried coating layer.

Also, the step (b-4) is performed by furnace annealing (FA) or rapid thermal annealing (RTA).

Also, the first coating layer and the second coating layer are formed of ferroelectrics.

The ferroelectric may be a ferroelectric of the formula ABO ₃ wherein A is at least one selected from the group consisting of lead (Pb), barium (Ba), strontium (Sr), calcium (Ca), lanthanum (La), potassium (K) And B is at least one species selected from the group consisting of Ti, Zr, Nb, Ta, Y, Dy, Mn, Gd, ) And iron (Fe). The present invention also provides a method for forming a thick film coating layer.

Also, the ferroelectric is PBZ ((Pb, Ba) ZrO ₃ ).

And, the present invention proposes a thick film coating layer produced by the above method.

According to the present invention, a coating layer is further formed on the upper surface of a coating layer formed by an aerosol deposition method (AD) through a chemical solution deposition (CSD) such as a sol-gel process, It is possible to obtain a thick film coating layer having uniform physical properties regardless of its position.

1 is a schematic view showing a process of manufacturing a sol solution for forming a second coating layer in the present embodiment.
2 is a scanning electron microscope (SEM) photograph of the surface of the PBZ coating layer prepared in Example 1 and Comparative Example 1 of the present application.
3 is a scanning electron microscope (SEM) photograph of the longitudinal cross-section of the PBZ coating layer prepared in Example 1 and Comparative Example 1 of the present application.
4 (a) to 4 (c) are hysteresis loops comparing the polarization characteristics between the coating layer prepared in Examples 1 to 3 and the coating layers prepared in Comparative Examples 1 to 3.

Hereinafter, the present invention will be described in detail.

In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Embodiments in accordance with the concepts of the present invention can make various changes and have various forms, so that specific embodiments are illustrated in the drawings and described in detail in this specification or application.

It should be understood, however, that it is not intended to limit the embodiments according to the concepts of the present invention to the particular forms of disclosure, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

In this specification, the terms "comprises ",or" having ", and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

A method for forming a thick film coating having improved surface roughness according to the present invention includes the steps of: (a) forming a first coating layer on an substrate by aerosol deposition (AD); (b) forming a second coating layer by chemical solution deposition (CSD) on the first coating layer, each of which will be described in detail below.

The step (a) is a step of forming a first coating layer on a substrate by using an aerosol deposition (AD), and one or more kinds of raw material powders are prepared according to a known method, 1 < / RTI > coating layer.

In this step (a), for example, at least one kind of raw material powders (a-1) are prepared and mixed (when two or more kinds of raw material powders are used) and calcined and then subjected to a known milling process such as ball milling, Preparing a powder having an appropriate particle size at the position; And (a-2) sequentially forming a first coating layer on the substrate with an aerosol deposition using the powder obtained in the step (a-1).

Further, the step (a-3) may be further followed by a step of heat-treating the first coating layer after performing the step (a-2), if necessary, in order to achieve crystallization and densification of the coating layer. A method such as furnace annealing (FA), rapid thermal annealing (RTA), excimer laser annealing (ELA), spark annealing, and plasma annealing But is not limited thereto.

The material of the at least one powder used in the aerosol deposition process for forming the first coating layer is not particularly limited and may be, for example, a ferroelectrics material. As the ferroelectric material, A representative example is a material having a perovskite structure or a perovskite crystal structure.

At this time, the material having the perovskite crystal structure may be represented by the following general formula (1).

1) ABO ₃

In the above 1), A is at least one selected from the group consisting of lead (Pb), barium (Ba), strontium (Sr), calcium (Ca), lanthanum (La), potassium (K) And B is at least one element selected from the group consisting of titanium (Ti), zirconium (Zr), niobium (Nb), tantalum (Ta), yttrium (Y), dysprosium (Dy), manganese (Mn), gadolinium (Gd), cobalt (Fe)).

Further, the material having the composite perovskite structure may have the following 2) or 3) composition.

2) xPb (A 1, A 2, ..., B 1, B 2, ...) 0 ₃ + (1- x) PbTiO ₃

3) xPb (A 1, A 2, ..., B 1, B 2, ...) 0 3 + (1- x) Pb (Zr, Ti) O 3

(2) and 3), x is a molar fraction, 0 < x < 1, and A1, A2, ... Is at least one element selected from the group consisting of Zn, Mg, Ni, Lu, In and Sc, and B1, B2, ... Is at least one element selected from the group consisting of Nb, Ta, Mo and W)

Next, the step (b) is a step of forming a second coating layer on the first coating layer formed in the step (a) through a chemical solution deposition (CSD).

For reference, the chemical solution deposition method is a method of depositing a coating layer having a desired composition through a chemical reaction based on a liquid phase. Typically, a sol-gel method, a metal organic decomposition method (MOD) Belongs.

Particularly, in the sol-gel method, a polymerized precursor solution is used by hydrolysis and polycondensation (also referred to as "hydrolysis condensation") of a compound such as a metal alkoxide. Such a sol-gel method has an advantage in that the composition of the metal alkoxide solution is controlled to be good, while the hydrolysis-condensation reaction is a non-reversible reaction, so that once crosslinked and polymerized, it can not be used as a sol-gel raw material .

In the present invention, a specific process for forming the second coating layer on the first coating layer using the sol-gel method is as follows: (b-1) preparing a sol solution containing a precursor compound; (b-2) applying the sol solution onto the first coating layer; (b-3) drying the applied coating layer; And (b-4) heat-treating the dried coating layer.

The step (b-1) is a step of preparing a solution containing a compound to be a precursor of the active material forming the coating layer. In this step, the precursor compound is introduced into a solvent according to a known method commonly used in the art Then, an acid component such as hydrochloric acid is added as a catalyst, and the mixture is stirred to proceed a hydrolysis and condensation reaction to form a gelated sol solution, and if necessary, further hydrolysis and condensation reaction are carried out, Aging can be carried out for a certain period of time.

At this time, the precursor compound may be a metal organic compound such as metal alkoxide, metal acetylacetate, or metal organic acid salt, or a metal inorganic compound such as nitrate, chloride, etc., a compound of a known type commonly used for forming a sol solution in a sol- Lt; / RTI &gt;

For example, in the case of forming a second coating layer composed of PBZ ((Pb, Ba) ZrO ₃ ) as a lead-based perovskite piezoelectric material, lead acetate is used as the lead precursor and barium acetate barium acetate, and zirconium butoxide may be used as the zirconium precursor.

If necessary, the solution may contain at least one selected from the group consisting of polymethylmethacrylate (PMMA), polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyvinylacetate, cellulose acetate, Ethyl cellulose, ethyl polyvinyl alcohol, pullulan, carboxyl methyl cellulose and the like as binders.

Wherein the step (b-2) is a step of applying the solution prepared in the step (b-1) on the first coating layer, wherein the step (b-1) spin coating, dip coaitng, or spraying.

The step (b-3) is a step of drying the coating layer applied on the first coating layer. This step may be performed without limitation of spray drying, tray drying, freeze drying, solvent drying, have.

Next, the step (b-4) is a step of heat-treating the metal foam, and the crystallization and densification of the amorphous active material coating layer formed on the metal foam surface and the inner pore wall through the step (c) do.

The step (b-4) may be performed by a method such as furnace annealing (FA), rapid thermal annealing (RTA), excimer laser annealing (ELA), spark annealing, and plasma annealing annealing, etc. However, the present invention is not limited thereto.

By carrying out this step, not only the crystallization of the second coating layer but also the effect of improving the crystallinity of the first coating layer formed by the aerosol deposition and removing the defects in the coating layer can be achieved at the same time.

The material forming the second coating layer formed in step (b) may be different from the material forming the first coating layer, but it is more preferable that the material forming both coating layers is the same.

According to the present invention, a coating layer is further formed on the upper surface of a coating layer formed by an aerosol deposition method (AD) through a chemical solution deposition (CSD) such as a sol-gel process, It is possible to obtain a thick film coating layer having uniform physical properties regardless of its position.

For example, when a thick film coating layer made of a ferroelectric layer material is formed by using the present invention, a ferroelectric coating layer having excellent surface flatness is formed, thereby preventing dielectric breakdown due to thickness nonuniformity of the coating layer even when a high voltage is applied A high reliability thick film layer having excellent dielectric strength characteristics can be realized.

Hereinafter, the present invention will be described in detail on the basis of embodiments. The presented embodiments are illustrative and are not intended to limit the scope of the invention.

<Example 1> AD process - Preparation of PBZ thick film coating layer by sol-gel process

In Example 1, a PBZ ((Pb, Ba) ZrO ₃ ) thick film having excellent surface flatness on a substrate was prepared by aerosol deposition (AD) and sol-gel process as described below.

1) Formation of first coating layer using AD process

First, in order to form the first coating layer through the AD process, wet ball milling was performed for 48 hours using 0.8 mol of PbO powder, 0.2 mol of BaCO ₃ powder, 1 mol of ZrO ₂ powder and ethanol, And then annealed at 1000 ℃ for 4 hours to obtain Pb _0.8 Ba _0.2 ZrO3 powder, which was charged into a powder feeder of an aerosol deposition apparatus and subjected to an AD process.

Specifically, the feeder was vigorously shaken using a vibrator in order to improve the fluidity and scattering of the granular powder in the powder feeder, and the scattered PBZ powder was aerosolized by the transfer gas at a flow rate of 20 l / min, (Pt coated Si substrate) mounted in a chamber in which a vacuum degree of several torr was maintained, thereby forming a PBZ coating layer having a thickness of 3 탆.

2) Formation of second coating layer by sol-gel process

First, as shown in Fig. 1, a sol solution was prepared.

1.5 g of lead acetate and 5.07 g of prepionic acid were stirred and refluxed at 110 ° C. for 2 hours to obtain 1.73 g of 80% zirconium butoxide, 4.94 g of methoxyethanol were mixed and stirred. After refluxing at 90 ° C for 2 hours, the solution was mixed and stirred, and then refluxed at 150 ° C for 4 hours to prepare Pb _0.11 ZrO ₃ .

Then, 0.61 g of barium acetate and 3.38 g of propionic acid were mixed and stirred, then refluxed at 110 ° C. for 2 hours, and 3.29 g of 80% zirconium butoxide 1.15 g of methoxyethanol was mixed and stirred, For 2 hours, the solution was mixed and stirred, and then refluxed at 150 캜 for 4 hours to prepare BaZrO ₃ .

Next, 0.6 mol of Pb _0.11 ZrO ₃ prepared above and 0.4 mol of BaZrO ₃ were mixed and stirred, and then refluxed at 150 ° C for 1 hour to prepare a sol solution in which PBZ (Pb _0.66 Ba _0.4 ZrO ₃ ) was dispersed Respectively.

Then, the sol solution was spin-coated on the substrate on which the first coating layer was formed (3000 rpm, 1 minute), and then dried at 350 ° C.

Finally, a substrate having the first coating layer and the second coating layer formed thereon was coated with a PBZ thick film coating layer having a total thickness of 3.3 占 퐉 including a second coating layer having a thickness of 0.3 占 퐉 formed by rapid thermal annealing (RTA) at 700 占 폚 for 5 minutes .

&Lt; Example 2 > AD process - Preparation of PBZ thick film coating layer by sol-gel process

A PBZ thick film coating layer was obtained in the same manner as in Example 1, except that the substrate on which the first coating layer was formed after the AD process was further subjected to rapid thermal annealing (RTA) at 700 캜 for 5 minutes.

&Lt; Example 3 > AD process - Preparation of PBZ thick film coating layer by sol-gel process

A PBZ thick film coating layer was obtained in the same manner as in Example 1, except that the substrate on which the first coating layer and the second coating layer were formed was subjected to furnace annealing at 700 ° C for one hour instead of the RTA process.

&Lt; Comparative Example 1 > Preparation of PBZ thick film coating layer by AD process

In order to form the coating layer through the AD process, wet ball milling was performed using 0.8 mol of PbO powder, 0.2 mol of BaCO ₃ powder, 1 mol of ZrO ₂ powder and ethanol for 48 hours, 4 hours to obtain Pb _0.8 Ba _0.2 ZrO 3 powder, which was charged into the powder feeder of the aerosol deposition apparatus and subjected to the AD process.

Specifically, the feeder was vigorously shaken using a vibrator in order to improve the fluidity and scattering of the granular powder in the powder feeder, and the scattered PBZ powder was aerosolized by the transfer gas at a flow rate of 20 l / min, (Pt coated Si substrate) mounted in a chamber in which a vacuum degree of several torr was maintained, thereby forming a PBZ coating layer having a thickness of 3 탆.

&Lt; Comparative Example 2 > Production of coating layer of PBZ thick film through AD process

A PBZ thick film coating layer was obtained in the same manner as in Comparative Example 1, except that the substrate on which the coating layer was formed after the AD process was further subjected to rapid thermal annealing (RTA) at 700 ° C for 5 minutes.

Experimental Example 1 Microstructure observation of the PBZ thick film coating layer prepared in Example 1 and Comparative Example 1

FIG. 2 is a scanning electron microscope (SEM) photograph of the surface of the PBZ coating layer prepared in Example 1 and Comparative Example 1 of the present invention, showing that the coating layer prepared in Example 1 of the present invention had a surface It is easy to see smooth and flat with the naked eye.

FIG. 3 is a scanning electron microscope (SEM) photograph of the longitudinal cross-section of the PBZ coating layer prepared in Example 1 and Comparative Example 1 of the present invention, showing that the coating layer prepared in Comparative Example 1, It can be seen that the applied coating layer has almost the same thickness at any position in the horizontal direction of the coating layer.

<Experimental Example 2> Observation of polarization characteristics of the PBZ thick film coating layers prepared in Examples 1-3 and 1-2

4 (a) to 4 (c) are hysteresis loops comparing the polarization characteristics between the coating layer prepared in Examples 1 to 3 and the coating layers prepared in Comparative Examples 1 to 3.

4 (a) to 4 (c), the PBZ thick film coating layers of Examples 1 to 3 having the first coating layer formed by the AD process and the second coating layer through the sol-gel process were formed by the AD process It can be seen that a saturation polarization (Ps) and a remanent polarization (Pr) are exhibited without exception, as compared with the PBZ thick film coating layers of Comparative Examples 1 and 2 which are made of only the coating layer.

Claims (10)

(a) forming a first coating layer on the substrate by aerosol deposition (AD); And
(b) forming a second coating layer by chemical solution deposition (CSD) on the first coating layer. The method according to claim 1,
Wherein the step (a) comprises the steps of:
(a-1) preparing at least one raw material powder, mixing, calcining and milling the powder to prepare a powder; And
(a-2) forming a first coating layer on the substrate with an aerosol deposition using the prepared powder. 3. The method of claim 2,
(A-3) after the step (a-2) is further performed, a step of heat-treating the first coating layer. The method according to claim 1,
Wherein the step (b) is performed by a sol-gel process. 5. The method of claim 4,
Wherein the step (b) comprises the following steps:
(b-1) preparing a sol solution containing a precursor compound;
(b-2) applying the sol solution onto the first coating layer;
(b-3) drying the applied coating layer; And
(b-4) heat treating the dried coating layer. 6. The method of claim 5,
Wherein the step (b-4) is performed by furnace annealing (FA) or rapid thermal annealing (RTA). The method according to claim 1,
Wherein the first coating layer and the second coating layer are made of ferroelectrics. 8. The method of claim 7,
Wherein the ferroelectric is represented by the following formula: &lt; EMI ID =
[Chemical Formula]
ABO ₃
Wherein A is at least one selected from the group consisting of lead (Pb), barium (Ba), strontium (Sr), calcium (Ca), lanthanum (La), potassium (K) and sodium (Na) (Ti), Zr, Nb, Ta, Y, Dy, Mn, Gd, Co and Fe One or more selected). The method according to claim 8, wherein the ferroelectric is PBZ ((Pb, Ba) ZrO ₃ ). A thick film coating layer produced by the method according to any one of claims 1 to 9.

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