JP6204154B2 - Fine structure, method for producing the same, and aliphatic polycarbonate - Google Patents

Description

  The present invention relates to a microstructure, a method for producing the same, and an aliphatic polycarbonate.

  Conventionally, a structure formed by MEMS (Micro Electro Mechanical Systems) technology, which is a representative example of a fine structure, has been used as an acceleration sensor, an angular velocity sensor, or μ-TAS (Micro-Total Analysis Systems) in the industry. ing. In general, a fine structure is manufactured by performing fine processing on silicon. Also, the progress of technology related to such production is remarkable.

  On the other hand, using a hard mask formed by photolithography instead of silicon, polypropylene carbonate (also referred to as “PPC” in the present application) patterned by plasma etching by RIE (Reactive Ion Etching) as a sacrificial layer, A technique for forming a structure made of a silicon oxide film is disclosed (Non-Patent Document 1).

Holly A Reed et al., “Fabrication of microchannels using polycarbonates as sacificial materials”, Institute of Physics Publishing, J. Am. Micromech Microeng. 11, 2001, p. 733-737

  However, the fine structure using silicon as a base material and the structure disclosed in Non-Patent Document 1 are all under reduced pressure or high vacuum during various processes for manufacturing the structure. A chamber and vacuum pump for processing are required. Furthermore, in order to form a pattern with high dimensional accuracy using a photolithography method, it is necessary to go through many processes using an expensive apparatus. Therefore, as long as a so-called vacuum process or a process using a photolithography method is employed, the manufacturing cost of the fine structure increases, and not only the time required for the manufacturing increases, but also the number of manufacturing processes is considered. In addition, a decrease in yield is inevitable.

  The present invention solves at least one of the above-described problems, and can be manufactured even under atmospheric pressure, has a large dimensional freedom and can have high dimensional accuracy, And greatly contribute to the realization of the manufacturing process.

  Inventors of the present application, if a photolithography method is employed to realize pattern formation with high dimensional accuracy even for a fine structure utilizing an aliphatic polycarbonate, processing of silicon that has been conventionally employed We focused on the problem that it was difficult to differentiate from the structure formed by Furthermore, even when the type of material is severely limited, such as a structure formed by anodic bonding between glass and silicon, it is not easy to realize various performances required by the industry. Therefore, the inventors of the present application have conducted intensive studies for solving such problems. As a result of many trials and errors and analysis, the inventors of the present invention either perform stamping on the aliphatic polycarbonate itself without relying on a vacuum process or a photolithography method for patterning the aliphatic polycarbonate with dimensional accuracy, or It has been found that performing an embossing process on a base for forming an aliphatic polycarbonate layer is an effective means that can solve the above technical problem. In particular, it has been found that the formation of a pattern by embossing an aliphatic polycarbonate itself can achieve higher dimensional accuracy. The present invention has been created based on the above viewpoint and analysis.

  One method for producing a fine structure of the present invention is a method for producing a fine structure having a through hole and / or a non-through hole, and embossing an aliphatic polycarbonate or a base of the aliphatic polycarbonate. A patterning step of patterning the aliphatic polycarbonate, a precursor layer forming step of forming a first metal oxide precursor layer covering the aliphatic polycarbonate and the base, and a first metal oxide precursor layer And removing the above-mentioned aliphatic polycarbonate during heating to obtain the first metal oxide layer.

  According to this fine structure manufacturing method, when patterning an aliphatic polycarbonate serving as a so-called sacrificial layer, an embossing process is performed on the base of the aliphatic polycarbonate or the aliphatic polycarbonate, for example, several tens of nm to several Pattern formation with a very large dimensional freedom of 100 μm and high dimensional accuracy can be realized even under atmospheric pressure. Therefore, according to this method for manufacturing a fine structure, it is possible to reduce the manufacturing cost of the fine structure and shorten the time required for the manufacturing. In addition, since it is not necessary to go through a complicated process in a strictly controlled work environment like the photolithography method, the yield can be improved. Furthermore, by appropriately selecting the material of the first metal oxide precursor layer, the first metal oxide layer that can have various electrical characteristics such as an insulator, a conductor, or a semiconductor, various stress characteristics, and the like is described above. As described above, through holes and / or non-through holes with high dimensional accuracy can be provided. Moreover, since the through-hole and / or the non-through-hole are formed using the aliphatic polycarbonate that can be removed by heating as a sacrificial layer, it can be said that there is almost no influence of the residue of the aliphatic polycarbonate in the manufactured microstructure. For example, when an aliphatic polycarbonate is formed by firing after an embossing process is performed on a base formed by application of the solution using an aliphatic polycarbonate solution as a starting material, the fat The dimensional accuracy of the group polycarbonate will be further increased.

  One microstructure of the present invention is a microstructure having a through hole and / or a non-through hole, and an aliphatic polycarbonate patterned by embossing, and the aliphatic polycarbonate. While the first metal oxide precursor layer covering the base is heated to obtain the first metal oxide layer, the aliphatic polycarbonate is removed, whereby the above-described through hole and / or the above non-through hole are formed. Is formed.

  According to this microstructure, since it is patterned by embossing an aliphatic polycarbonate serving as a sacrificial layer, it has a very large dimensional freedom, for example, several tens of nanometers to several hundreds of micrometers, and high dimensions. It can have a pattern of precision. In addition, by appropriately selecting the material of the first metal oxide precursor layer, the first metal oxide layer that can have various electrical characteristics such as an insulator, a conductor, or a semiconductor, various stress characteristics, and the like is described above. As described above, through holes and / or non-through holes with high dimensional accuracy can be provided. Therefore, this microstructure having through holes and / or non-through holes formed by such embossing can be widely used as a part of a precise device. Further, since the through hole and / or the non-through hole is formed using the aliphatic polycarbonate that can be removed by heating as a sacrificial layer, it can be said that there is almost no influence of the residue of the aliphatic polycarbonate on the fine structure.

  Another microstructure of the present invention is a microstructure having a through hole and / or a non-through hole, and an aliphatic polycarbonate substrate patterned by embossing, and the fat While the first metal oxide precursor layer covering the aromatic polycarbonate is heated to obtain the first metal oxide layer, the aliphatic polycarbonate is removed to remove the through hole and / or the non-through hole. Is formed.

  According to this microstructure, since the aliphatic polycarbonate that is the sacrificial layer is patterned by the base of the aliphatic polycarbonate that has been embossed, the dimensional freedom is very high, for example, from several tens of nanometers to several hundreds of micrometers. And a pattern with high dimensional accuracy can be obtained. In addition, since the object to be embossed is the base, the degree of freedom in the thickness of the base is increased, so the degree of freedom in designing the microstructure is also increased. In addition, by appropriately selecting the material of the first metal oxide precursor layer, the first metal oxide layer that can have various electrical characteristics such as an insulator, a conductor, or a semiconductor penetrates with high dimensional accuracy as described above. Holes and / or non-through holes can be provided. Therefore, this microstructure having through holes and / or non-through holes formed by such embossing can be widely used as a part of a precise device. Further, since the through hole and / or the non-through hole is formed using the aliphatic polycarbonate that can be removed by heating as a sacrificial layer, it can be said that there is almost no influence of the residue of the aliphatic polycarbonate on the fine structure.

  Further, one aliphatic polycarbonate of the present invention is an aliphatic polycarbonate used for forming a fine structure having through holes and / or non-through holes, and is patterned by embossing. While the first metal oxide precursor layer covering the state is heated to obtain the first metal oxide layer, it is removed to form the aforementioned through hole and / or the aforementioned non-through hole. .

  According to this aliphatic polycarbonate, the aliphatic polycarbonate patterned by embossing is utilized as a sacrificial layer for a microstructure having a through hole and / or a non-through hole. Therefore, it is possible to contribute to the realization of a pattern having a very large dimensional freedom and high dimensional accuracy by the stamping process. Moreover, since the through-hole and / or the non-through-hole are formed using the aliphatic polycarbonate that can be removed by heating as a sacrificial layer, it can be said that the residue of the aliphatic polycarbonate hardly affects the fine structure. The aliphatic polycarbonate may be patterned by embossing the aliphatic polycarbonate itself or by embossing the base of the aliphatic polycarbonate.

  In each of the above-described inventions, the base is the second metal oxide precursor layer, and the base is the first metal by heating the first metal oxide precursor layer and the base. Being a second metal oxide that adheres to the oxide layer is another preferred embodiment that can be employed. In particular, adhesion between the first metal oxide and the second metal oxide in the process of being heated or as a result of heating leads to an increase in the reliability and stability of the microstructure.

  The “substrate” in the present application is not limited to the foundation of the plate-like body, but includes other forms of foundations or base materials. Further, the “layer” in the present application is a concept including not only a layer but also a film. Conversely, the “film” in the present application is a concept including not only a film but also a layer. In addition, the “base” in the present application refers to a base for forming a film (or layer), and the form thereof is not particularly limited.

  According to one manufacturing method of a fine structure of the present invention, when patterning an aliphatic polycarbonate serving as a so-called sacrificial layer, by embossing the aliphatic polycarbonate or the base of the aliphatic polycarbonate, Pattern formation with a high degree of dimensional freedom and high dimensional accuracy can be realized even under atmospheric pressure.

  In addition, according to one microstructure of the present invention, since the aliphatic polycarbonate serving as the sacrificial layer is patterned by embossing, it always has a large dimensional freedom and a pattern with high dimensional accuracy. be able to. Further, according to another microstructure of the present invention, since the aliphatic polycarbonate that is a sacrificial layer is patterned by the base of the aliphatic polycarbonate that has been embossed, the dimensional freedom is very large, And it can have a pattern with high dimensional accuracy. In addition, since the object to be embossed is the base, the degree of freedom in the thickness of the base is increased, so the degree of freedom in designing the microstructure is also increased.

  In addition, according to one aliphatic polycarbonate of the present invention, the aliphatic polycarbonate patterned by embossing is sacrificed for a microstructure having through holes and / or non-through holes. Since it is used as a layer, it can contribute to the realization of a pattern with a very large dimensional freedom and high dimensional accuracy by embossing.

It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 1st Embodiment of this invention. It is an AFM image of an example of the fine pattern of the aliphatic polycarbonate layer in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 1st Embodiment of this invention. It is a cross-sectional SEM photograph of an example of the microstructure in the 1st Embodiment of this invention. It is a graph which shows the TG-DTA characteristic of the aliphatic polycarbonate in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the microstructure in the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram of the other fine structure in the 2nd Embodiment of this invention.

  A fine structure and a method for manufacturing the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this description, common parts are denoted by common reference symbols throughout the drawings unless otherwise specified. In the drawings, elements of the present embodiment are not necessarily described with each other kept to scale. Further, some symbols may be omitted to make each drawing easier to see.

<First Embodiment>
1. 1 to 4, 6, and 7 are cross-sectional schematic views showing one process of the method for manufacturing the fine structure 100. In the present embodiment, the microstructure 100 includes at least one selected from the group of through holes and non-through holes. FIG. 8 is a cross-sectional SEM photograph of an example of the microstructure 100 in the present embodiment.

(1) Production process of aliphatic polycarbonate Polypropylene carbonate (PPC), which is one of the representative examples of the aliphatic polycarbonate of this embodiment, was produced as follows.

  First, an organozinc catalyst that is a metal catalyst is manufactured. Specifically, in a 300 mL four-necked flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, zinc oxide 8.1 g (100 mmol), glutaric acid 12.7 g (96 mmol), Acetic acid 0.1 g (2 mmol) and toluene 130 g (150 mL) were charged. Next, after replacing the inside of the reaction system with a nitrogen atmosphere, the temperature of the flask was raised to 55 ° C., and the mixture was stirred at the same temperature for 4 hours to carry out the reaction treatment of each of the aforementioned materials. Thereafter, the temperature was raised to 110 ° C., and the mixture was further stirred for 4 hours at the same temperature for azeotropic dehydration to remove only moisture. Then, the reaction liquid containing an organozinc catalyst was obtained by cooling the flask to room temperature.

  A portion of this reaction solution was collected and filtered, and IR was measured (product name: AVATAR360, manufactured by Thermo Nicolay Japan Co., Ltd.). As a result, no peak based on the carboxylic acid group was observed.

  Next, after the inside of a 1 L autoclave system equipped with a stirrer, a gas introduction pipe, and a thermometer was previously replaced with a nitrogen atmosphere, 8.0 mL of the reaction solution containing the above-described organic zinc catalyst (1.0 g of the organic zinc catalyst was added) Containing), 131 g (200 mL) of hexane, and 46.5 g (0.80 mol) of propylene oxide. Next, carbon dioxide was added while stirring to replace the inside of the reaction system with a carbon dioxide atmosphere, and carbon dioxide was charged until the inside of the reaction system became 1.5 MPa. Thereafter, the autoclave was heated to 60 ° C., and a polymerization reaction was carried out for 6 hours while supplying carbon dioxide consumed by the reaction.

  After completion of the reaction, the autoclave was cooled, depressurized and filtered. Thereafter, 80.8 g of PPC (which may contain inevitable impurities. The same applies hereinafter) was obtained by drying under reduced pressure.

The obtained PPC could be identified from the following physical properties.
IR (KBr) absorption peak: 1742, 1456, 1381, 1229, 1069, 787 (both units are cm ^-1 )
The number average molecular weight of the obtained PPC was 52,000.

  By the way, although the number average molecular weight of the above-mentioned aliphatic polycarbonate was 52000, it is not limited to this value. For example, if the number average molecular weight is 5,000 to 1,000,000, it can be suitably used. A more preferred number average molecular weight is 10,000 to 500,000. In addition, when the number average molecular weight of the aliphatic polycarbonate is less than 5000, the viscosity of the solution becomes low when the aliphatic polycarbonate solution is used, and handling becomes difficult, and the dimensional freedom of the aliphatic polycarbonate after patterning decreases. Problems may occur. Further, when the number average molecular weight of the aliphatic polycarbonate exceeds 1,000,000, the viscosity of the solution becomes high when the aliphatic polycarbonate solution is used, and handling becomes difficult, and the dimensional accuracy of the aliphatic polycarbonate after patterning decreases. The problem can arise.

[Method for measuring number average molecular weight of aliphatic polycarbonate]
A chloroform solution having an aliphatic polycarbonate concentration of 0.5% by mass was prepared and measured using a high performance liquid chromatograph. After the measurement, the molecular weight was calculated by comparing with polystyrene having a known number average molecular weight measured under the same conditions. The measurement conditions are as follows.
Model: HLC-8020
Column: GPC column (trade name of Tosoh Corporation: TSK GEL Multipore HXL-M)
Column temperature: 40 ° C
Eluent: Chloroform Flow rate: 1 mL / min

  Moreover, in this embodiment, the organic solvent employ | adopted for the solution containing an aliphatic polycarbonate will not be specifically limited if it is an organic solvent which can melt | dissolve an aliphatic polycarbonate. Specific examples of the organic solvent include diethylene glycol monoethyl ether acetate, α-terpineol, β-terpineol, N-methyl-2-pyrrolidone, isopropyl alcohol, diethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether, toluene, cyclohexane, methyl ethyl ketone, dimethyl carbonate , Diethyl carbonate, propylene carbonate and the like.

  Moreover, the kind of aliphatic polycarbonate used by this embodiment is not specifically limited. Preferably, an endothermic decomposition type aliphatic polycarbonate having good thermal decomposability is used. In addition, it can be confirmed by the differential thermal measurement method (DTA) that the thermal decomposition reaction of the aliphatic polycarbonate is an endothermic reaction. Such an aliphatic polycarbonate has a high oxygen content and can be decomposed into a low molecular weight compound at a relatively low temperature, thereby reducing the residual amount of impurities typified by carbon impurities in the metal oxide. Contribute positively.

  In addition, for example, an aliphatic polycarbonate obtained by polymerizing epoxide and carbon dioxide is also a suitable aspect that can be employed in the present embodiment. By using an aliphatic polycarbonate obtained by polymerizing such an epoxide and carbon dioxide, an aliphatic polycarbonate having a desired molecular weight capable of improving endothermic degradability can be obtained by controlling the structure of the aliphatic polycarbonate. An effect is produced. In particular, aliphatic polycarbonate is at least one selected from the group consisting of polyethylene carbonate and polypropylene carbonate from the viewpoint of high oxygen content and decomposition into a low molecular weight compound at a relatively low temperature. It is preferable.

  The above epoxide is not particularly limited as long as it is an epoxide that becomes an aliphatic polycarbonate having a structure containing an aliphatic group in the main chain by a polymerization reaction with carbon dioxide. For example, ethylene oxide, propylene oxide, 1-butene oxide, 2-butene oxide, isobutylene oxide, 1-pentene oxide, 2-pentene oxide, 1-hexene oxide, 1-octene oxide, 1-decene oxide, cyclopentene oxide, cyclohexene oxide Styrene oxide, vinylcyclohexene oxide, 3-phenylpropylene oxide, 3,3,3-trifluoropropylene oxide, 3-naphthylpropylene oxide, 3-phenoxypropylene oxide, 3-naphthoxypropylene oxide, butadiene monooxide, 3- Epoxys such as vinyloxypropylene oxide and 3-trimethylsilyloxypropylene oxide are examples that can be employed in this embodiment. Among these epoxides, ethylene oxide and propylene oxide are preferably used from the viewpoint of high polymerization reactivity with carbon dioxide. In addition, each above-mentioned epoxide may be used individually, respectively, and can also be used in combination of 2 or more type.

  As described above, as an example of a method for producing an aliphatic polycarbonate, a method in which the above-described epoxide and carbon dioxide are subjected to a polymerization reaction in the presence of a metal catalyst may be employed.

  Moreover, the typical example of the above-mentioned metal catalyst is an aluminum catalyst or a zinc catalyst. Among these, a zinc catalyst is preferably used because it has high polymerization activity in the polymerization reaction of epoxide and carbon dioxide. Further, as described above, an organic zinc catalyst is particularly preferably used among the zinc catalysts.

A typical example of the above-mentioned organozinc catalyst is
Organozinc catalysts such as zinc acetate, diethyl zinc, dibutyl zinc; or
With organic zinc catalysts obtained by reacting compounds such as primary amines, divalent phenols, divalent aromatic carboxylic acids, aromatic hydroxy acids, aliphatic dicarboxylic acids, and aliphatic monocarboxylic acids with zinc compounds is there.
Among these organic zinc catalysts, since it has higher polymerization activity, it is preferable to employ an organic zinc catalyst obtained by reacting a zinc compound, an aliphatic dicarboxylic acid, and an aliphatic monocarboxylic acid. It is an aspect.

  Moreover, it is preferable that the usage-amount of the above-mentioned metal catalyst used for a polymerization reaction is 0.001-20 mass parts with respect to 100 mass parts of epoxides, and it is more preferable that it is 0.01-10 mass parts. . When the usage-amount of a metal catalyst is less than 0.001 mass part, there exists a possibility that a polymerization reaction may become difficult to advance. Moreover, when the usage-amount of a metal catalyst exceeds 20 mass parts, there exists a possibility that there may be no effect corresponding to a usage-amount and it may become economical.

The reaction solvent used as needed in the above polymerization reaction is not particularly limited. Various organic solvents can be applied as the reaction solvent. Specific examples of this organic solvent are:
Aliphatic hydrocarbon solvents such as pentane, hexane, octane, decane and cyclohexane;
Aromatic hydrocarbon solvents such as benzene, toluene, xylene;
Chloromethane, methylene dichloride, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, ethyl chloride, trichloroethane, 1-chloropropane, 2-chloropropane, 1-chlorobutane, 2-chlorobutane, 1-chloro-2 -Halogenated hydrocarbon solvents such as methylpropane, chlorobenzene, bromobenzene;
And carbonate solvents such as dimethyl carbonate, diethyl carbonate, and propylene carbonate.

  Moreover, it is preferable that the usage-amount of the above-mentioned reaction solvent is 500 to 10000 mass parts with respect to 100 mass parts of epoxides from a viewpoint of making reaction smooth.

  In the above polymerization reaction, the method of reacting epoxide and carbon dioxide in the presence of a metal catalyst is not particularly limited. For example, a method may be employed in which the above epoxide, metal catalyst, and reaction solvent as required are charged into an autoclave and mixed, and then carbon dioxide is injected to react.

  In addition, the operating pressure of carbon dioxide used in the above polymerization reaction is not particularly limited. Typically, the pressure is preferably 0.1 MPa to 20 MPa, more preferably 0.1 MPa to 10 MPa, and further preferably 0.1 MPa to 5 MPa. When the use pressure of carbon dioxide exceeds 20 MPa, there is a possibility that the effect corresponding to the use pressure may not be obtained and it may not be economical.

  Moreover, the polymerization reaction temperature in the above-mentioned polymerization reaction is not particularly limited. Typically, the temperature is preferably 30 to 100 ° C, and more preferably 40 to 80 ° C. When the polymerization reaction temperature is less than 30 ° C., the polymerization reaction may take a long time. On the other hand, when the polymerization reaction temperature exceeds 100 ° C., side reactions occur and the yield may decrease. Since the polymerization reaction time varies depending on the polymerization reaction temperature, it cannot be generally stated, but typically it is preferably 2 hours to 40 hours.

  After completion of the polymerization reaction, an aliphatic polycarbonate can be obtained by filtering off by filtration or the like, washing with a solvent or the like if necessary, and drying.

(2) Aliphatic polycarbonate embossing step Next, as a starting material, a solution of polypropylene carbonate (PPC), which is the aliphatic polycarbonate of this embodiment, becomes the base of this aliphatic polycarbonate as shown in FIG. An aliphatic polycarbonate layer 20 is formed on a silicon substrate (hereinafter also simply referred to as “substrate”) 10. In addition, the solvent of the solution for forming the aliphatic polycarbonate layer 20 of the present embodiment is dimethyleneethyl ether (also expressed as DGMEE), and the concentration of PPC as a solute is 6.25%. In this embodiment, the aliphatic polycarbonate layer 20 having a thickness of 330 nm is formed on the substrate 10 by spin coating. In addition, the desired thickness of the aliphatic polycarbonate layer 20 can be obtained according to the conditions and / or the number of times of spin coating.

  In the present embodiment, the stamping process is performed on the precursor layer having a high plastic deformation ability. As a result, even when the pressure applied when performing the die pressing process is a low pressure of 0.1 MPa or more and 20 MPa or less, each precursor layer comes to deform following the surface shape of the die, and the desired die The push structure can be formed with high accuracy. In addition, by setting the pressure within a low pressure range of 0.1 MPa or more and 20 MPa or less, the mold is less likely to be damaged during the stamping process, and it is advantageous for increasing the area.

  Here, the reason why the pressure is within the range of “0.1 MPa to 20 MPa” is as follows. First, if the pressure is less than 0.1 MPa, the pressure may be too low to emboss each precursor layer. When polypropylene carbonate is used as the aliphatic polycarbonate, since the polypropylene carbonate is a relatively soft material, the embossing can be performed even at about 0.1 MPa. On the other hand, if the pressure is 20 MPa, the precursor layer can be sufficiently embossed, so that it is not necessary to apply more pressure. From the viewpoint described above, it is more preferable that the embossing process is performed at a pressure within the range of 0.5 MPa or more and 10 MPa or less in the embossing process in the second embodiment.

Note that the substrate 10 forming the base of the present embodiment is not limited to the above-described silicon substrate, and a substrate used for a general electronic device or MEMS (or NEMS, Nano Electro Mechanical Systems) may be used. it can. For example, high heat-resistant glass, SiO ₂ / Si substrate (that is, a substrate in which a silicon oxide film is formed on a silicon substrate), alumina (Al ₂ O ₃ ) substrate, STO (SrTiO) substrate, SiO ₂ layer on the surface of Si substrate In addition, various insulating substrates including a semiconductor substrate (for example, a Si substrate, a SiC substrate, a Ge substrate, etc.) such as an insulating substrate in which an STO (SrTiO) layer is formed via a Ti layer can be applied. The insulating substrate is made of materials such as polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins, cellulose triacetate, polycarbonate, polyamide, polyimide, polyamideimide, polysulfone, aramid, and aromatic polyamide. Film or sheet is included. Further, the thickness of the substrate is not particularly limited, but is, for example, 3 μm or more and 300 μm or less. Further, the substrate may be hard or flexible.

  Thereafter, pre-baking is performed in which the aliphatic polycarbonate layer 20 is heated in the atmosphere at 150 ° C. for a predetermined time (for example, 5 minutes). In this preliminary calcination, PPC itself is not decomposed or substantially not decomposed, but the solvent component is almost lost by evaporation or decomposition.

  In the present embodiment, after preliminary firing, the aliphatic polycarbonate layer 20 is embossed. Specifically, as shown in FIG. 2, in the state heated to 100 ° C. or more and 200 ° C. or less (typically 150 ° C.), the first metal oxide precursor layer mold M1 is used. An embossing process is performed on the aliphatic polycarbonate layer 20 at a pressure of 1 MPa to 20 MPa (typically 10 MPa). As a result, as shown in FIG. 3, an embossed structure of the aliphatic polycarbonate layer 20 is formed.

Thereafter, in this embodiment, plasma is irradiated under atmospheric pressure, and the entire aliphatic polycarbonate layer 20 is etched from the surface side. Specifically, the aliphatic polycarbonate layer 20 is etched by plasma formed under the condition that 15 W of power is applied in a state where oxygen (O ₂ ) is introduced into the etching treatment chamber. As a result, as shown in FIG. 4, the aliphatic polycarbonate layer 20 in the region where the pattern is not formed (removal target region) is removed, while the aliphatic polycarbonate layer 20 in the region where the pattern is formed has a certain thickness or more. In order to leave, a pattern is finally formed. It should be noted that in the present embodiment, pattern formation with a very large dimensional freedom and high dimensional accuracy, for example, several tens nm to several hundreds μm can be realized even under atmospheric pressure. Deserve.

  As a more specific example of this embodiment, a fine pattern formed by a layer made of PPC which is the aliphatic polycarbonate layer 20 is shown. FIG. 5 is an AFM image of an example of a fine pattern of the aliphatic polycarbonate layer 20 in the present embodiment. As shown in FIG. 5, it can be confirmed that a line-and-space pattern having a width and height of 500 nm or less can be formed with high dimensional accuracy.

  Here, performing the above-described plasma etching under atmospheric pressure after the embossing process is performed, the removal of the remaining film (unnecessary portion) of the aliphatic polycarbonate layer 20 subjected to the embossing process is more accurately performed. This is a preferred embodiment from the viewpoint of easy realization. By this etching process, the final aliphatic polycarbonate layer 20 can be thinned (for example, about 10 nm to 30 nm) with higher accuracy. In addition, it is one aspect | mode which can also employ | adopt removing the residual film (unnecessary part) of the aliphatic polycarbonate layer 20, for example by ultraviolet rays or combined use of ultraviolet rays and ozone instead of atmospheric pressure etching. Therefore, various known means can be employed to remove the remaining film (unnecessary portion) of the aliphatic polycarbonate layer 20 that has been embossed.

(3) Step of Forming First Metal Oxide Precursor Layer Thereafter, as shown in FIG. 6, the first metal oxide precursor solution is used as a starting material on the patterned aliphatic polycarbonate layer 20 and the substrate 10. The first metal oxide precursor layer 30 is formed by a spin coating method. The desired thickness of the first metal oxide precursor layer 30 and the first metal oxide layer can be obtained depending on the conditions and / or the number of times of spin coating.

  In addition, the method of forming the aliphatic polycarbonate layer 20 and the first metal oxide precursor layer 30 of the present embodiment is not limited to the spin coating method. Formation of a layer using a manufacturing process with low energy consumption is a preferable embodiment. Other more specific examples include printing methods such as gravure printing, screen printing, offset printing, and inkjet printing, or coating methods such as roll coating, die coating, air knife coating, blade coating, reverse coating, and gravure coating. In particular, it is preferable to form a layer on the substrate by a spin coating method, which is a simple method, and screen printing.

(4) Step of forming first metal oxide layer by main firing In the present embodiment, the first metal oxide precursor layer 30 is preheated at 100 ° C. and then heated at 400 ° C. By performing the main firing, the first metal oxide layer 32 is formed as shown in FIG. Here, the example of the 1st metal oxide obtained by baking the 1st metal oxide precursor of this embodiment is an oxide semiconductor (it may contain an unavoidable impurity. The same hereafter) when oxidized. A structure in which a ligand is coordinated to a metal to be an oxide insulator (which may contain unavoidable impurities; the same shall apply hereinafter) or an oxide conductor (which may include unavoidable impurities; hereinafter the same shall apply) (typically It is a material having a complex structure. Therefore, in order to obtain a desired performance, one or more of the first metal oxides having the above-described characteristics can be selected. For example, a metal organic acid salt, a metal inorganic acid salt, a metal halide, or various metal alkoxides may be included in the precursor of the first metal oxide of the present embodiment. An example of a typical first metal oxide precursor is a solution in which zirconium (IV) tetrabutoxide and 2-ethylhexanezirconium are dissolved in propionic acid. Zirconium oxide can be formed by baking this solution. Another example is a solution in which indium acetylacetonate and zinc chloride are dissolved in propionic acid. By baking this solution, indium-zinc oxide which is an oxide semiconductor can be formed.

  Examples of the metal that becomes an oxide conductor when oxidized are one or two selected from the group consisting of indium, ruthenium, zinc, tin, indium-zinc, indium-tin, and indium-gallium-zinc. More than species. Note that each metal described above can serve not only as an oxide conductor but also as an oxide semiconductor when oxidized.

  Examples of metals that become oxide semiconductors when oxidized are indium, tin, zinc, cadmium, titanium, silver, copper, tungsten, nickel, indium-zinc, indium-tin, indium-gallium-zinc, antimony -1 type (s) or 2 or more types selected from the group of tin and gallium-zinc are mentioned. However, in terms of element performance and stability, it is preferable that indium and indium-zinc be employed as a metal that becomes an oxide semiconductor when oxidized.

Examples of metals that become oxide insulators when oxidized include zirconium, silicon,
One type or two or more types selected from the group of titanium, tantalum, bismuth, niobium, and lanthanum-zirconium may be mentioned. Note that each metal described above can serve not only as an oxide insulator but also as an oxide semiconductor when oxidized.

(5) Step of removing aliphatic polycarbonate layer in the course of main firing After the preliminary firing is performed on the first metal oxide precursor layer 30 described above, the process of the main firing that is heated at 400 ° C. ( Typically, the decomposition reaction of the aliphatic polycarbonate layer 20 occurs during the temperature rising process). In other words, the aliphatic polycarbonate layer 20 is removed while the first metal oxide precursor layer 30 is heated to obtain the first metal oxide layer 32. As a result, as shown in FIG. 7, a microstructure 100 having a through hole and / or a non-through hole (V region in FIG. 7) formed by the first metal oxide layer 32 and the substrate 10 is manufactured. . In addition, although the through-hole or non-through-hole of this embodiment can be utilized as a fluid flow path, the utilization example of a through-hole or non-through-hole is not limited to a flow path. For example, when the non-through hole is a hollow structure formed by the first metal oxide layer 32, a structure in which a hollow structure such as a micropump in the field of MEMS or NEMS is combined can be manufactured. From a possible viewpoint, this is a preferred embodiment that can be adopted.

  As a more specific example of the present embodiment, a microstructure 100 having a through hole and / or a non-through hole formed by a layer of zirconium oxide as the first metal oxide layer 32 and the substrate 10 is shown. . FIG. 8 is a cross-sectional SEM photograph of an example of the microstructure 100 in the present embodiment. Note that the through hole and / or the non-through hole is indicated by a V region. FIG. 8 shows that through holes and / or non-through holes having a width of about 400 nm and a height of about 50 nm can be formed with high dimensional accuracy.

[TG-DTA (thermogravimetry and differential heat) characteristics evaluation of aliphatic polycarbonate]
By the way, as described in the above (4) and (5), the removal of the aliphatic polycarbonate layer 20 in the process of forming the first metal oxide means that the TG- of the polypropylene carbonate of this embodiment shown in FIG. This is supported by the DTA characteristics.

  FIG. 9 is a graph showing the TG-DTA characteristics of the aliphatic polycarbonate (more specifically, PPC) of this embodiment. In addition, the continuous line in FIG. 9 is a thermogravimetric (TG) measurement result, and the dotted line in the figure is a differential heat (DTA) measurement result.

  From the results of thermogravimetry in FIG. 9, a significant decrease in weight due to decomposition or removal of PPC was observed from around 140 ° C. to around 190 ° C. In addition, it is thought that PPC has changed into carbon dioxide and water by this decomposition. Further, from the results shown in FIG. 9, it was confirmed that PPC was decomposed and removed by 90 wt% or more in the vicinity of 190 ° C. In more detail, it can be seen that PPC is decomposed by 95 wt% or more near 250 ° C., and almost all PPC is decomposed (99 wt% or more) near 260 ° C. Therefore, if the temperature at which the first metal oxide is formed (the temperature for the main firing) is 260 ° C. or higher, the aliphatic polycarbonate layer 20 is removed as shown in FIGS. Note that even when the space indicated by V in FIGS. 7 and 8 is a closed space, the gas (carbon dioxide or water vapor) generated by the decomposition of polypropylene is the first metal oxide layer 32 or the first metal oxide. It is considered that the first metal oxide precursor layer up to the layer 32 passes through the first metal oxide precursor layer.

  As described above, when forming the microstructure 100, the aliphatic polycarbonate of the present embodiment heats the first metal oxide precursor layer 30 that covers the state patterned by embossing. While the one metal oxide layer 32 is obtained, it is removed as a sacrificial layer. Therefore, it is possible to contribute to the realization of a pattern having a very large dimensional freedom and high dimensional accuracy by the stamping process. Moreover, since the through-hole and / or the non-through-hole are formed using the aliphatic polycarbonate that can be removed by heating as a sacrificial layer, it can be said that the residue of the aliphatic polycarbonate hardly affects the fine structure.

  Further, according to the microstructure 100 of the present embodiment, when the aliphatic polycarbonate layer 20 serving as a so-called sacrificial layer is patterned, the aliphatic polycarbonate 20 is embossed, for example, several tens nm to several hundreds. Pattern formation with a very large dimensional freedom of μm and high dimensional accuracy can be realized even under atmospheric pressure. Therefore, according to the microstructure 100 and the manufacturing method thereof, the manufacturing cost of the microstructure 100 can be reduced and the time required for the manufacturing can be shortened. In addition, in this embodiment, since it is not necessary to go through complicated steps in a strictly controlled work environment like the photolithography method, the yield can be improved. Furthermore, by appropriately selecting the material of the first metal oxide precursor layer 30, the first metal oxide layer 32 that can have various electrical characteristics such as an insulator, a conductor, or a semiconductor, various stress characteristics, and the like can be obtained. As described above, through holes and / or non-through holes with high dimensional accuracy can be provided. Moreover, since the through-hole and / or the non-through-hole are formed using the aliphatic polycarbonate that can be removed by heating as a sacrificial layer, it can be said that there is almost no influence of the residue of the aliphatic polycarbonate in the manufactured microstructure. Furthermore, in this embodiment, since the aliphatic polycarbonate layer 20 is formed by firing after applying a stamping process to the base material starting from the aliphatic polycarbonate solution, the aliphatic polycarbonate layer 20 The dimensional accuracy is further increased.

<Second Embodiment>
1. Overall Structure of Fine Structure of this Embodiment FIGS. 10 to 16 are cross-sectional schematic views showing one process of the method of manufacturing the fine structure 200, respectively. In the present embodiment, the fine structure 200 includes at least one selected from the group of through holes and non-through holes provided in the second metal oxide layer 212 that is the base, The same materials and processes as those in the first embodiment are employed. Therefore, the description which overlaps with 1st Embodiment may be abbreviate | omitted.

(1) Step of Forming Second Metal Oxide Precursor Layer In this embodiment, as shown in FIG. 10, the second metal oxide precursor solution is formed on the substrate 10 using the second metal oxide precursor solution as a starting material. The precursor layer 210 is formed by a spin coating method. The desired thickness of the second metal oxide precursor layer 210 and the second metal oxide layer can be obtained depending on the conditions and / or the number of times of spin coating. In addition, the base in the present embodiment is the second metal oxide precursor layer 210 or the second metal oxide layer 212.

  In addition, the example of the 2nd metal oxide obtained by baking the 2nd metal oxide precursor of this embodiment is an oxide semiconductor, an oxide insulation, when oxidized like the 1st metal oxide. It is a material having a structure (typically a complex structure) in which a ligand is coordinated to a metal to be a body or an oxide conductor. Therefore, in order to obtain desired performance, one or more of the second metal oxides having the above-described characteristics can be selected. Specific examples are the same as those of the first metal oxide.

  Thereafter, pre-baking is performed in which the second metal oxide precursor layer 210 is heated in the atmosphere at 100 ° C. for a predetermined time (for example, 5 minutes).

(2) Embossing process of the second metal oxide precursor layer After pre-baking, the second metal oxide precursor layer 210 is embossed. Specifically, as shown in FIG. 11, in the state heated to 100 ° C. or more and 300 ° C. or less (typically 200 ° C.), the second metal oxide precursor layer mold M2 is used. The embossing process is performed on the second metal oxide precursor layer 210 at a pressure of 1 MPa to 20 MPa (typically 10 MPa). As a result, as shown in FIG. 12, an embossed structure of the second metal oxide precursor layer 210 is formed.

(3) Step of forming aliphatic polycarbonate layer Starting from a solution of polypropylene carbonate (PPC), which is the aliphatic polycarbonate of this embodiment, on the second metal oxide precursor layer 210 serving as a base of this aliphatic polycarbonate Then, the aliphatic polycarbonate layer 20 is formed. As a result, as shown in FIG. 13, an aliphatic polycarbonate is ideally embedded in the recess provided in the second metal oxide precursor layer 210 so that the aliphatic polycarbonate is ideally buried on the second metal oxide precursor layer 210. A polycarbonate layer 20 is formed. In FIG. 13, the aliphatic polycarbonate is completely buried in the recesses included in the second metal oxide precursor layer 210, but the present embodiment is not limited to such an aspect. For example, even if a gap is temporarily formed in a part of the lower part of the concave part (that is, the substrate 10 side), if the upper side of the concave part is sufficiently filled, the first metal oxide precursor layer 30 described later and In the main firing step of the second metal oxide precursor layer 210, through holes and / or non-through holes (indicated by a V region in FIG. 16) are formed with high dimensional accuracy.

(4) Step of Forming Aliphatic Polycarbonate Pattern Thereafter, in the present embodiment, as in the first embodiment, plasma is irradiated under atmospheric pressure, and the entire second metal oxide precursor layer 210 is exposed on the surface side. Etch from. By adjusting the conditions such as the etching time, the aliphatic polycarbonate layer 20 is removed except for the aliphatic polycarbonate in the recess provided in the second metal oxide precursor layer 210, as shown in FIG. Therefore, the aliphatic polycarbonate (aliphatic polycarbonate layer 20) in the recess forms a pattern based on the shape of the recess.

(5) Step of Forming First Metal Oxide Precursor Layer Thereafter, as shown in FIG. 15, the first metal oxide is formed on the patterned aliphatic polycarbonate layer 20 and the second metal oxide precursor layer 210. Using the precursor solution as a starting material, the first metal oxide precursor layer 30 is formed by a spin coating method as in the first embodiment.

(6) First Metal Oxide Layer Forming Step by Main Firing In the present embodiment, the first metal oxide precursor layer 30 and the second metal oxide precursor layer 210 are pre-fired by heating at 100 ° C. Then, the first metal oxide layer 32 and the second metal oxide layer 212 are formed as shown in FIG.

(7) Step of removing aliphatic polycarbonate layer in the course of main firing After the preliminary firing is performed on the first metal oxide precursor layer 30 and the second metal oxide precursor layer 210 described above, In the process of the main baking (typically, the process of raising the temperature) that is heated at 400 ° C., a decomposition reaction of the aliphatic polycarbonate layer 20 in the recess occurs. In other words, while heating the first metal oxide precursor layer 30 and the second metal oxide precursor layer 210 to obtain the first metal oxide layer 32 and the second metal oxide layer 212, The aliphatic polycarbonate layer 20 is removed. As a result, as shown in FIG. 16, a microstructure having a through hole and / or a non-through hole (V region in FIG. 16) formed by the first metal oxide layer 32 and the second metal oxide layer 212. 200 is manufactured.

  The first metal oxide precursor layer 30 and the second metal oxide precursor layer 210, which is the base, are heated so that the base adheres to the first metal oxide layer 32. It is a very preferable aspect to select the material of the second metal oxide layer 212 so as to be 212. In particular, adhesion between the first metal oxide layer 32 and the second metal oxide layer 212 in the process of being heated or as a result of heating leads to an increase in the reliability and stability of the microstructure. .

  Also in this embodiment, the through hole or the non-through hole (the V region in FIG. 16) can be used as a fluid flow path, but examples of using the through hole or the non-through hole are limited to the flow path. Not. For example, when the non-through hole is a hollow structure formed by the first metal oxide layer 32 and the second metal oxide layer 212, for example, a combination of a hollow structure such as a micropump in the field of MEMS or NEMS is combined. This is a preferred embodiment that can be employed from the viewpoint of manufacturing a structure.

  In addition, since the shape of the second metal oxide layer 212 as a base can be freely designed by embossing, the thickness direction of the second metal oxide layer 212 (in other words, a through hole or a non-through hole) In the depth direction). Therefore, as shown in FIG. 17, by changing the mold for the second metal oxide precursor layer, the thickness direction of the second metal oxide layer 212 (in other words, a through hole or a non-through hole) It should be noted that more complicated microstructures 300 with different depth directions) can be manufactured.

<Other embodiments>
In the embossing step in each of the above-described embodiments, in advance, a mold release process for the surface of each precursor layer that the mold pressing surface is in contact with and / or a mold release process for the mold pressing surface of the mold is performed. Thereafter, it is preferable to perform a stamping process on each precursor layer. By performing such treatment, it is possible to reduce the frictional force between each precursor layer and the mold, and therefore it is possible to perform the stamping process with higher accuracy on each precursor layer. . Examples of the release agent that can be used for the release treatment include surfactants (for example, fluorine surfactants, silicon surfactants, nonionic surfactants, etc.), fluorine-containing diamond-like carbon, and the like. can do.

  As described above, the disclosure of each of the embodiments described above is described for explaining the embodiments, and is not described for limiting the present invention. In addition, modifications within the scope of the present invention including other combinations of the embodiments are also included in the claims.

  The present invention can be applied to a wide range of industrial fields such as an electronic device field including various sensors, a MEMS (NEMS) field, and a medical equipment field.

DESCRIPTION OF SYMBOLS 10 Board | substrate 20 Aliphatic polycarbonate layer 30 1st metal oxide precursor layer 32 1st metal oxide layer 100,200,300 Fine structure 210 2nd metal oxide precursor layer 212 2nd metal oxide layer M1 1st Metal oxide precursor layer mold M2 Second metal oxide precursor layer mold

Claims (16)

A method of manufacturing a microstructure having a through hole and / or a non-through hole,
By applying embossing to the aliphatic Polycarbonate, a patterning step of patterning the aliphatic polycarbonate,
Cormorant covering the aliphatic Polycarbonate, precursor layer formation ligand metal of the metal oxide to form a first metal oxide precursor layer made of a material having a coordination structure when oxidized Process,
Removing the aliphatic polycarbonate while obtaining the first metal oxide layer by heating the first metal oxide precursor layer at a temperature higher than the temperature at which the aliphatic polycarbonate is decomposed by 99 wt% or more ; including,
A manufacturing method of a fine structure. The aliphatic polycarbonate is at least one selected from the group consisting of polyethylene carbonate and polypropylene carbonate.
The manufacturing method of the fine structure according to claim 1 . The non-through hole forms a hollow structure;
The manufacturing method of the fine structure of Claim 1 or Claim 2 . A microstructure having a through hole and / or a non-through hole,
Covering the patterned aliphatic Polycarbonate by performing embossing, the first metal oxide includes a material ligands to the metal as a metal oxide has a coordination structure when oxidized precursor While the layer is heated at a temperature higher than the temperature at which the aliphatic polycarbonate is decomposed by 99 wt% or more to obtain the first metal oxide layer, the through hole and / or the A non-through hole is formed,
Fine structure. A microstructure having a through hole and / or a non-through hole,
Includes a material having a structure in which a ligand is coordinated to a metal that becomes a metal oxide when oxidized , covering an aliphatic polycarbonate substrate patterned by embossing and the aliphatic polycarbonate By removing the aliphatic polycarbonate while heating the first metal oxide precursor layer at a temperature higher than the temperature at which the aliphatic polycarbonate is decomposed by 99 wt% or more to obtain the first metal oxide layer. The through hole and / or the non-through hole is formed,
Fine structure. The base is a second metal oxide precursor layer, and the first metal oxide precursor layer and the base are heated to thereby bond the base to the first metal oxide layer. Become oxide,
The microstructure according to claim 5 . The aliphatic polycarbonate is at least one selected from the group consisting of polyethylene carbonate and polypropylene carbonate.
The microstructure according to any one of claims 4 to 6 . The non-through hole forms a hollow structure;
The microstructure according to any one of claims 4 to 7 . An aliphatic polycarbonate used in forming a microstructure having a through hole and / or a non-through hole,
A first metal oxide precursor layer that includes a material having a structure in which a ligand is coordinated to a metal that becomes a metal oxide when oxidized , covering the patterned state by performing an embossing process ; The through hole and / or the non-through hole are formed by being removed while heating the aliphatic polycarbonate at a temperature higher than the temperature for decomposing 99 wt% or more to obtain the first metal oxide layer.
Aliphatic polycarbonate. The aliphatic polycarbonate is at least one selected from the group consisting of polyethylene carbonate and polypropylene carbonate.
The aliphatic polycarbonate according to claim 9 . A method of manufacturing a microstructure having a through hole and / or a non-through hole,
A patterning step of patterning the aliphatic polycarbonate on the base by embossing the base of the aliphatic polycarbonate; and
A precursor layer that forms a first metal oxide precursor layer that includes a material having a structure in which a ligand is coordinated to a metal that becomes a metal oxide when oxidized, covering the aliphatic polycarbonate and the base. Forming process;
Removing the aliphatic polycarbonate while obtaining the first metal oxide layer by heating the first metal oxide precursor layer at a temperature higher than the temperature at which the aliphatic polycarbonate is decomposed by 99 wt% or more; including,
A manufacturing method of a fine structure. The base is a second metal oxide precursor layer, and the first metal oxide precursor layer and the base are heated to thereby bond the base to the first metal oxide layer. Become oxide,
The manufacturing method of the fine structure of Claim 11. The aliphatic polycarbonate is at least one selected from the group consisting of polyethylene carbonate and polypropylene carbonate.
The manufacturing method of the fine structure of Claim 11 or Claim 12. The non-through hole forms a hollow structure;
The method for manufacturing a fine structure according to any one of claims 11 to 13. An aliphatic polycarbonate used in forming a microstructure having a through hole and / or a non-through hole,
A material having a structure in which a ligand is coordinated to a metal that becomes a metal oxide when oxidized, covering the base and the aliphatic polycarbonate patterned by embossing an aliphatic polycarbonate base The first metal oxide precursor layer containing is removed while being heated at a temperature higher than the temperature at which the aliphatic polycarbonate is decomposed by 99 wt% or more to obtain the first metal oxide layer, thereby removing the through hole. And / or the non-through hole is formed,
Aliphatic polycarbonate. The aliphatic polycarbonate is at least one selected from the group consisting of polyethylene carbonate and polypropylene carbonate.
The aliphatic polycarbonate according to claim 15.