JP5155059B2 - Manufacturing method of surface modified substrate - Google Patents

Description

  The present invention relates to a method for producing a surface-modified substrate in which a modification layer is provided on the substrate surface.

  With the recent progress of production technology and analysis technology, substrates having higher functions have been vigorously developed in various fields. Such a substrate for analysis is mainly provided with a large number of minute patterns by arranging chemical substances and compositions on the surface and patterning them. On the other hand, shortening the period of research and product development has become a major issue, and in order to improve the analysis efficiency, it is strongly desired to develop a substrate that can simultaneously analyze a large number of samples. This is particularly noticeable in the medical / pharmaceutical field where a huge amount of sample needs to be processed in a short time.

Examples of such a substrate for analysis include a substrate whose surface is modified so as to specifically detect a biological substance, and a substrate whose surface is modified so that cells to be analyzed can be immobilized.
For example, by immobilizing cells on the substrate surface, it becomes possible to elucidate biological phenomena, produce useful substances, and assay for analyzing cellular responses such as physiological activities and toxicity of chemical substances. In addition, it is expected that the development of artificial organs using cultured cells will greatly advance by applying such immobilization technology.
Therefore, a method has been proposed in which cells are arranged in a minute region on a substrate by patterning a minute region having different cell adhesiveness on the substrate surface and selectively adhering the cell to a region having high cell adhesiveness ( For example, see Patent Document 1).

As described above, in a substrate in which a predetermined region on the surface is modified, it may be necessary to provide a recess in the unmodified region on the substrate surface depending on the purpose. A conventional method for manufacturing such a surface-modified substrate will be described with reference to FIG. FIG. 3 is a cross-sectional view for explaining an example of a conventional manufacturing process of the surface-modified substrate.
First, as shown in FIG. 3A, a substrate 91 having a concave portion 910 formed on the surface 91a is produced. The substrate 91 can be easily manufactured, for example, by covering the substrate surface 91a with a mask corresponding to the pattern of the recesses 910 and etching. The mask may be made of a photoresist, a metal such as chromium (Cr) or nickel (Ni).
Next, as shown in FIG. 3B, the entire surface of the substrate 91 on which the recesses 910 are formed is covered with a negative or positive photoresist 93.
Then, using a mask selected according to the type of the photoresist, the photoresist 93 is exposed from the substrate surface 91a side and developed, thereby patterning the resist layer 93 ′ as shown in FIG. To do.
Next, the entire surface of the substrate 91 covered with a predetermined portion with the resist layer 93 ′ is coated with a modifying agent, whereby the modifying layer is formed on the substrate surface 91a and on the resist layer 93 ′ as shown in FIG. A substrate 91 on which 95 is laminated is obtained.
Next, the modification layer 95 on the resist layer 93 ′ is removed together with the resist layer 93 ′ covered with the modification layer 95, thereby exposing the concave surface 910a as shown in FIG. A surface-modified substrate 9 in which the substrate surface 91a excluding the surface 910a is coated with the modification layer 95 is obtained.
Japanese Patent Laid-Open No. 5-176653

  However, in the method shown in FIG. 3, if the patterning accuracy of the resist layer 93 ′ is poor in FIG. 3C, for example, as shown in FIG. The layered portion of the layer 93 ′ will not match. In this case, a part of the concave surface 910a is not covered with the resist layer 93 ', and a part of the substrate surface 91a excluding the concave surface 910a is covered with the resist layer 93'. When the subsequent process is performed using the substrate in such a state, a modification layer 95 is laminated on the exposed concave surface 910a and covered with a resist layer 93 ′ as shown in FIG. 4B. The modification layer 95 is not laminated on the substrate surface 91a. Therefore, in the surface modified substrate 9 obtained by removing the resist layer 93 ′, as shown in FIG. 4C, a part of the recessed surface 910a is covered with the modified layer 95, and the substrate surface 91a excluding the recessed surface 910a is covered. Is exposed without being covered with the modification layer 95. Therefore, the pattern of the concave portion 910 when viewed from above the substrate 91 and the pattern of the unmodified portion 902 not covered with the modification layer 95 do not match, and the modification accuracy of the substrate surface 91a is inferior. . And the surface modification board | substrate with which modification precision fell remarkably is not suitable for practical use.

  Such a decrease in modification accuracy is caused by a decrease in patterning accuracy of the resist layer 93 ′, as shown in FIG. The patterning accuracy of the resist layer 93 ′ is likely to decrease as the modification pattern on the substrate surface becomes finer. For example, it is difficult to efficiently manufacture a surface-modified substrate having a fine modification pattern on the order of nanometers. There is a case. That is, the conventional manufacturing method has a problem that it is not necessarily suitable for manufacturing a surface-modified substrate having a fine modification pattern on the surface.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the manufacturing method of the surface modification board | substrate which has a fine and highly accurate modification pattern on the surface.

To solve the above problem,
The invention according to claim 1 is a method of manufacturing a surface-modified substrate having a modification layer provided on the substrate surface, wherein a predetermined portion of the light-transmitting substrate surface is covered with a metal mask, etched, and then etched. A step of forming a recess on the surface, a step of covering the entire surface of the substrate with a negative photoresist without removing the metal mask, and exposing the negative photoresist from the back side of the substrate, A step of patterning a resist layer by development, a step of removing the metal mask without removing the resist layer, and then covering the entire surface of the substrate with a modifier to provide a modified layer; and the resist And a step of removing the modification layer on the layer together with the resist layer covered with the modification layer.
The invention described in claim 2 is a group consisting of CF ₄ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₆ , C ₄ F ₈ , C ₅ F ₈ , CHF ₃ , CH ₂ F ₂ and SF _6. The method for producing a surface-modified substrate according to claim 1, wherein the recess is formed by dry etching using plasma generated from at least one gas selected from the group consisting of:
The invention according to claim 3 is characterized in that a liquid repellent treatment agent that exhibits liquid repellency is used as the modifier, and the modification layer is made liquid repellant. It is a manufacturing method of a modified substrate.
The invention according to claim 4 is characterized in that the liquid repellent treatment agent is a compound represented by the following general formula (1) or (2). It is.

(In the formula, R ¹ represents a linear or branched perfluoroalkyl group or perfluoroalkyl ether group having ^{1 to} 16 carbon atoms; R ¹ ′ represents a linear or branched chain having ^{1 to} 16 carbon atoms; Represents a group in which one fluorine atom is removed from a perfluoroalkyl group or a perfluoroalkyl ether group; R ² is any one of groups represented by the following formulas (11) to (16), and a plurality of R ² may be the same or different; Y is a group represented by the formula “—NH—C (═O) —” or a carbonyl group, and a plurality of Y may be the same or different; Is an ethyleneoxy group in which one or more hydrogen atoms may be replaced by an alkyl group or alkyloxyalkyl group in which one hydrogen atom is substituted, and a plurality of Z may be the same or different from each other Even J and k are each independently 0 or 1, and a plurality of j or k may be the same or different from each other; l and m are each independently an integer of 0 or more, and a plurality of l or m may be the same or different from each other; when l is an integer of 2 or more, one Z may be the same or different from each other.

(In the formula, R ³ represents a hydroxyl group or an atom or group that can be substituted with a hydroxyl group; R ⁴ represents a hydrogen atom or a monovalent hydrocarbon group; n is 1, 2 or 3, and n is 2 or 3; And n R ³ may be the same or different from each other; when n is 1, the two R ⁴ may be the same or different from each other.)
The invention described in claim 5 is characterized in that the compound represented by the general formula (1) or (2) is represented by the following general formula (3) or (4). This is a method for producing a surface-modified substrate.

(In the formula, R ¹ represents a linear or branched perfluoroalkyl group or perfluoroalkyl ether group having ^{1 to} 16 carbon atoms; R ¹ ′ represents a linear or branched chain having ^{1 to} 16 carbon atoms; Represents a group in which one fluorine atom is removed from a perfluoroalkyl group or a perfluoroalkyl ether group; R ² is any one of groups represented by the following formulas (11) to (16), and a plurality of R ² may be the same or different; m is an integer of 0 or more, and a plurality of m may be the same or different.

(In the formula, R ³ represents a hydroxyl group or an atom or group that can be substituted with a hydroxyl group; R ⁴ represents a hydrogen atom or a monovalent hydrocarbon group; n is 1, 2 or 3, and n is 2 or 3; And n R ³ may be the same or different from each other; when n is 1, the two R ⁴ may be the same or different from each other.)

  ADVANTAGE OF THE INVENTION According to this invention, the surface modification board | substrate which has a fine and highly accurate modification pattern on the surface can be manufactured stably. For example, since a surface-modified substrate having a fine modification pattern on the order of nanometers can be efficiently produced, the present invention is suitable for producing a cell array chip or the like.

The method for producing a surface-modified substrate of the present invention is a method for producing a surface-modified substrate in which a modification layer is provided on the surface of the substrate, covering a predetermined portion of the substrate surface having optical transparency with a metal mask, and etching. A step of forming a recess on the surface of the substrate, a step of covering the entire surface of the substrate with a negative photoresist without removing the metal mask, and exposing the negative photoresist from the back side of the substrate. And then developing to pattern the resist layer, removing the metal mask without removing the resist layer, and then coating the entire surface of the substrate with a modifier to provide a modification layer; Removing the modification layer on the resist layer together with the resist layer covered with the modification layer.
In the present invention, the modified layer refers to a layer that is laminated on the substrate surface and has different properties from the substrate surface.
Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view for explaining an example of the manufacturing process of the surface modified substrate of the present invention.
First, as shown in FIG. 1A, a predetermined portion on the surface 11 a of the substrate 11 is covered with a metal mask 12. The metal mask 12 may be produced by, for example, forming a metal thin film on the substrate surface 11a by sputtering or the like, laminating a photoresist on the metal thin film, patterning, and performing wet etching.

The substrate 11 is made of a light-transmitting material. Examples of such a material include quartz (SiO 2), glass, silicon nitride (SiN), sapphire, and resin, and quartz and glass are particularly preferable. In addition, a transparent electrode film such as a silicon nitride film (SiN), a silicon oxide film (SiO2), ITO, or sapphire is formed on a base material such as quartz (SiO2), glass, silicon nitride (SiN), sapphire, or resin. The substrate 11 may be used as the substrate 11. The material of the substrate 11 is preferably as high as possible. Here, “having optical transparency” means having transparency to the exposure light of a photoresist described later. In general, light having a wavelength in the ultraviolet region is used for exposure of a photoresist, and therefore, a material that absorbs less light is preferable.
What is necessary is just to select the thickness and surface area of the board | substrate 11 suitably according to the objective. The present invention is particularly suitable for the production of a surface-modified substrate having a fine modification pattern. However, considering application to a cell array chip or the like, for example, the thickness is usually 0.1 to 10 mm. Is preferable, and it is more preferable that it is 0.15-1.5 mm. If it is such a range, it will become especially excellent in the fine workability of the board | substrate 11, and the usability of the obtained surface modification board | substrate.

The metal mask 12 is preferably as low as possible. Specific examples of the material include chromium (Cr), nickel (Ni), aluminum (Al), tantalum (Ta), and titanium (Ti). Alternatively, a metal mask having a two-layer structure in which these metals are deposited on the surface of the substrate 11 as an adhesive layer and gold (Au), silver (Ag), or platinum (Pt) is further laminated on the surface may be used. For the metal mask 12, it is preferable to appropriately select a material that does not transmit the exposure light in accordance with the wavelength of the exposure light in the exposure process described later.
The thickness of the metal mask 12 may be appropriately adjusted in consideration of the thickness of the substrate 11 and the depth of the concave portion to be formed. However, when the thickness of the substrate 11 is within the above range, the thickness is usually 0. It is preferable that it is 05-2.0 micrometers, and it is more preferable that it is 0.1-1.0 micrometer.

  Next, as shown in FIG. 1B, the concave portion 110 is formed by performing wet etching on the substrate 11 whose predetermined portions are covered with the metal mask 12. The wet etching method may be appropriately selected depending on the material of the substrate 11. For example, when the material of the substrate 11 is glass, etching using buffered hydrofluoric acid (BHF) is preferable.

The concave portion 110 has a bowl shape, and its front surface 110a is curved so as to bulge toward the substrate rear surface 11b side, and has the deepest depth at the center. The recess 110 has a substantially circular outer shape when viewed from above the substrate 11 (not shown).
What is necessary is just to adjust the magnitude | size of the recessed part 110 suitably according to the objective. For example, in the case of the surface-modified substrate having a fine modification patterns such as cell array chips, it is preferable that the width _{X 1} of the recess 110 is 5 to 500 [mu] m, and more preferably 15 to 200 m. It is preferable that the maximum depth _{Y 1} of the recess 110 is 0.1～7Myuemu, and more preferably 0.5 to 5 [mu] m.
The area of the opening 110b of the recess 110 may be appropriately adjusted according to the purpose. Similarly, in the case of a cell array chip or the like, 1.9 × 10 ^{−11 to} 2.5 × 10 ⁻⁷ m ² is preferable, and 1.7 × 10 ⁻¹⁰ to 4 × 10 ⁻⁸ m ² is more preferable.

  Through such an etching process, the pattern of the recess 110 when viewed from above the substrate 11 matches the pattern of the exposed portion 101 not covered with the metal mask 12 with high accuracy.

Next, as shown in FIG. 1C, the entire surface of the substrate 11 on which the recesses 110 are formed is covered with a negative photoresist 13 without removing the metal mask 12. The negative photoresist 13 is not particularly limited and may be a known one.
Then, the negative photoresist 13 is exposed from the back surface 11 b side of the substrate 11. The exposure conditions may be the same as those from the normal substrate surface side, and may be set arbitrarily according to the purpose. As a result, the exposure light 14 passes through the substrate 11 from the rear surface 11b side, and the negative photoresist 13 is exposed at a portion where the metal mask 12 is not provided.

Then, the resist layer is patterned by developing after exposure. As a result, as shown in FIG. 1 (d), the substrate 11 is obtained in which the concave surface 110 a is coated with the resist layer 13 ′ corresponding to the coating pattern of the metal mask 12.
As described above, since the pattern of the concave portion 110 and the pattern of the exposed portion 101 coincide with each other with high accuracy, the resist layer 13 ′ is laminated only on the concave surface 110a through such exposure and development processes. Is done. Therefore, the pattern of the concave portion 110 and the pattern of the resist layer 13 ′ when viewed from above the substrate 11 coincide with each other with high accuracy.

  Next, by removing the metal mask 12 under the condition that the resist layer 13 ′ is not removed, as shown in FIG. 1E, the substrate 11 whose concave surface 110 a is covered with the resist layer 13 ′ is obtained. The removal of the metal mask 12 is preferably performed by a method similar to that used for the production, and is preferably performed by wet etching.

Next, the entire surface of the substrate 11 covered with a predetermined portion with the resist layer 13 ′ is coated with a modifying agent, so that the modifying layer is formed on the substrate surface 11a and on the resist layer 13 ′ as shown in FIG. A substrate 11 on which 15 is laminated is obtained.
In the present invention, the modifier refers to a substance that coats the substrate surface and expresses different properties from the substrate surface. Specific examples of the modifier include those that are simply laminated on the substrate surface without forming a chemical bond with the substrate, and those that are chemically bonded to the substrate and immobilized on the substrate surface. In any case, as the modifying agent, those having desired properties can be usually used before coating the substrate surface. Further, in the case of a modifier that forms a chemical bond with the substrate, it may have a desired property after the chemical bond is formed. Here, the chemical bond refers to a covalent bond or the like.

The coating method of the modifier may be appropriately selected according to the type of the modifier, and examples thereof include a dip coating method, a spin coating method, a vacuum deposition method, a CVD (chemical vapor deposition) method, and a plasma polymerization method. For example, in the case of the dip coating method, it is preferable to remove the solvent component by preparing a modifier solution, coating it and drying it.
The substrate 11 on which the modification layer 15 is laminated is washed and dried as necessary. For washing, alcohol such as methanol or ethanol may be used. For example, when the modifier solution contains a fluorinated solvent, a fluorinated solvent may be used.

  What is necessary is just to set the thickness of the modification layer 15 suitably according to the objective. Further, the thickness of the modification layer 15 can be adjusted by the molecular size and the amount of the modifier used.

Next, by removing the modification layer 15 on the resist layer 13 ′ together with the resist layer 13 ′ covered with the modification layer 15, the concave surface 110a is exposed as shown in FIG. The surface modified substrate 1 in which the substrate surface 11a excluding the surface 110a is coated with the modified layer 15 is obtained.
The removal of the modification layer 15 and the resist layer 13 ′ is preferably performed under wet conditions, and more preferably using various organic solvents, acids or alkalis depending on the type of the resist layer 13 ′.

  As described above, in the step of coating the substrate 11 with the modifying agent, the resist layer 13 ′ is laminated only on the concave surface 110a. Therefore, in the surface modified substrate 1, a part of the concave surface 110a is part of the modifying layer 15. And the substrate surface 11a excluding the concave surface 110a is not covered with the modification layer 15 and is not exposed. Therefore, the surface-modified substrate 1 in which the pattern of the concave portion 110 when viewed from above the substrate 11 and the pattern of the unmodified portion 102 not covered with the modifying layer 15 coincide with each other with high accuracy can be obtained. Thus, according to the present invention, it is possible to form a fine and highly accurate modified pattern and unmodified portion on the substrate surface.

FIG. 2 is a cross-sectional view for explaining another example of the manufacturing process of the surface modified substrate of the present invention.
First, as shown in FIG. 2A, a predetermined portion on the surface 21 a of the substrate 21 is covered with a metal mask 22.
The substrate 21 and the metal mask 22 are the same as the substrate 11 and the metal mask 12 in FIG.

Next, as shown in FIG. 2B, the concave portion 210 is formed by dry etching the substrate 21 whose predetermined portions are covered with the metal mask 22. The dry etching is preferably etching using plasma generated from a gas containing fluorine atoms. Preferred examples of such a gas include CF ₄ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₆ , C ₄ F ₈ , C ₅ F ₈ , CHF ₃ , CH ₂ F ₂ and SF _6. Examples include at least one selected from the group. If necessary, an argon (Ar), hydrogen _(H 2), oxygen _{(O 2)} and may be used in combination at least one gas selected from the group consisting of carbon monoxide (CO).

The recess 210 has a substantially cylindrical shape, and has a substantially circular outer shape when viewed from above the substrate 21 (not shown), and its bottom surface 210a is flat.
The size of the recess 210 may be adjusted similarly to the recess 110 in FIG. In the case of a surface-modified substrate having a fine modification pattern, the width X ₂ and the depth Y ₂ of the recess 210 may be the same as X ₁ and Y ₁ in FIG. Further, the area of the opening 210b of the recess 210 may be the same as the area of the opening 110b in FIG.

Dry etching can be performed as follows, for example. That is, the substrate carried into the vacuum layer is placed on and closely adhered to the electrostatic chuck, and the vacuum layer is evacuated to a pressure of preferably 0.01 Pa or less, and the substrate rear surface 21b is used for cooling. An inert gas is introduced to cool the substrate so that the substrate surface temperature during discharge is about 80 to 100 ° C. Next, a gas for generating plasma is introduced and adjusted so that the pressure in the vacuum layer is about 0.5 Pa, and the power of 500 to 2000 W is applied to the antenna and the power of 50 to 500 W is applied to the substrate as the bias power, respectively. By applying, the substrate is dry-etched to have a predetermined shape. Before the dry etching, if necessary, the substrate may be cleaned by pre-etching the substrate using plasma generated from argon or the like. Further, even after the dry etching, cleaning may be performed by ashing the impurity polymer adhering to the substrate using plasma generated from oxygen or the like, if necessary.
Through such an etching process, the pattern of the concave portion 210 when viewed from above the substrate 21 and the pattern of the exposed portion 201 not covered with the metal mask 22 coincide with each other with high accuracy.

Thereafter, the surface-modified substrate 2 is obtained as in the case described with reference to FIG.
First, as shown in FIG. 2C, the entire surface of the substrate 21 on which the recesses 210 are formed is covered with a negative photoresist 23 without removing the metal mask 22.
Then, the negative photoresist 23 is exposed from the back surface 21 b side of the substrate 21. The negative photoresist 23 and the exposure light 24 are the same as the negative photoresist 13 and the exposure light 14 in FIG.
Then, the resist layer is patterned by developing after exposure. Thereby, as shown in FIG. 2D, the substrate 21 in which the resist layer 23 ′ is laminated only on the concave surface 210a corresponding to the coating pattern of the metal mask 22 is obtained. The pattern of the concave portion 210 and the pattern of the resist layer 23 ′ when viewed from above the substrate 21 coincide with each other with high accuracy.

  Next, by removing the metal mask 22 under the condition that the resist layer 23 'is not removed, as shown in FIG. 2E, the substrate 21 having the concave surface 210a covered with the resist layer 23' is obtained. The removal of the metal mask 22 is preferably performed by a method similar to that used for the production, and is preferably performed by dry etching.

Next, the entire surface of the substrate 11 coated with a predetermined portion with the resist layer 23 ′ is coated with a modifying agent, so that the modifying layer is formed on the substrate surface 21a and the resist layer 23 ′ as shown in FIG. A substrate 21 on which 25 is laminated is obtained. The modification layer 25 is the same as the modification layer 15 in FIG.
Next, the modified layer 25 on the resist layer 23 ′ is removed together with the resist layer 23 ′ covered with the modified layer 25 by the same method as described with reference to FIG. As shown, the surface modified substrate 2 is obtained in which the concave surface 210a is exposed and the substrate surface 21a excluding the surface 210a is coated with the modifying layer 25.

  As described above, in the step of coating the substrate 21 with the modifier, since the resist layer 23 ′ is laminated only on the concave surface 210a, the pattern of the concave portion 210 when viewed from above the substrate 21, The surface modified substrate 2 in which the pattern of the unmodified portion 202 not covered with the modified layer 25 matches with high accuracy is obtained.

Here, an example in which the substrate is etched by wet etching in FIG. 1 and dry etching in FIG. 2 is shown. However, the etching method is arbitrary regardless of the shape of the recess on the substrate to be formed, for example. Can be selected. However, dry etching is preferably applied when forming a finer recess or a recess whose shape is precisely controlled.
The shape and size of the recess are not limited to those described with reference to FIGS. 1 and 2, and may be appropriately selected depending on the purpose by adjusting the etching conditions.
Moreover, it is preferable that the metal mask is produced and removed by the same method.
Further, when the metal mask is manufactured by wet etching, the substrate is preferably etched by wet etching. Similarly, when the metal mask is manufactured by dry etching, the substrate is preferably etched by dry etching. By doing so, the process can be simplified.
In the present invention, when dry etching is performed, etching may be performed using plasma, or may be performed by irradiation with ultraviolet light or ozone.

In the present invention, by appropriately selecting and forming a modified layer having specific properties, various surface modified substrates reflecting the properties can be produced. And this invention is especially suitable for manufacture of the surface modification board | substrate which has a fine modification pattern. For example, in various cell array chips such as a bio-related substance detection sensor, a cell adhesion substrate, a cell culture substrate, and a microelectrode array device for cell potential measurement, a layer having a minute liquid repellency at a predetermined position on the substrate surface (Hereinafter abbreviated as a liquid repellent layer) is formed, and the present invention is particularly suitable for the production of such a surface-modified substrate. Here, “liquid repellency” refers to “water repellency” and / or “oil repellency”.
Hereinafter, as an example, formation of a minute liquid repellent layer will be described.

The liquid repellent layer can be formed by using a liquid repellent treatment agent as a modifier and covering a predetermined portion on the substrate surface 11a or 12a.
For example, when manufacturing a cell array chip, the liquid repellent layer surface preferably has water repellency with a water contact angle of 100 ° or more, and has an oil repellency with a hexadecane contact angle of 50 ° or more. It is preferable. The magnitudes of water repellency and oil repellency can be adjusted by the type of the liquid repellent treatment agent.
By having such a liquid repellency, adsorption of a biological substance is suppressed on the surface of the liquid repellent layer. Therefore, a substance that specifically binds to the biological substance is not formed on the liquid-repellent layer. By selectively immobilizing on the modifying part, it is possible to manufacture a bio-related substance detection sensor or the like. In addition, since the adsorption of biological substances on the surface of the liquid repellent layer is suppressed, no scaffold is formed when the cells are adsorbed. Therefore, the cells are selectively adsorbed to the unmodified portion where the liquid repellent layer is not formed. By immobilizing them, it is possible to manufacture cell adhesion substrates, cell culture substrates, microelectrode array devices for cell potential measurement, and the like.

The liquid repellent layer may be any material. For example, it can be formed of a conventionally used liquid repellent agent such as polytetrafluoroethylene.
However, in the present invention, the liquid repellent layer preferably has a light transmitting property. The term “having light transparency” as used herein is different from the case of the substrates 11 and 21, and does not mean, for example, having transparency to ultraviolet light used when exposing a photoresist. It refers to having sufficient transparency with respect to a wide range of wavelengths, specifically ultraviolet light, visible light, and infrared light, and preferably has transparency with respect to visible light. By doing so, for example, when optically analyzing a cell to be measured using a microscope or the like, noise can be effectively reduced and analysis can be performed with higher sensitivity. In particular, it is suitable for irradiating a laser under microscope observation and applying a technique usually called optical tweezers or applying light stimulation to a cell for analysis. The liquid repellent layer preferably has the same transparency as transparent glass or quartz (SiO ₂ ). In order to make the liquid repellent layer have such light transmittance, it has a refractive index similar to that of silicon oxide film, quartz (SiO ₂ ), and glass, and has a wavelength of ultraviolet light, visible light, and infrared light. In contrast, a liquid repellent treatment agent that can form a film with a sufficiently thin thickness may be used. Preferred examples of such a liquid repellent treatment agent include fluorine-containing compounds having liquid repellency and light transmission.

  The fluorine-containing compound is preferably a compound having a perfluoroalkyl group or a perfluoroalkyl ether group at one end of the molecule, and more preferably a compound represented by the following general formula (1) or (2) (hereinafter, Examples thereof include compounds (1) and (2).

(In the formula, R ¹ represents a linear or branched perfluoroalkyl group or perfluoroalkyl ether group having ^{1 to} 16 carbon atoms; R ¹ ′ represents a linear or branched chain having ^{1 to} 16 carbon atoms; Represents a group in which one fluorine atom is removed from a perfluoroalkyl group or a perfluoroalkyl ether group; R ² is any one of groups represented by the following formulas (11) to (16), and a plurality of R ² may be the same or different; Y is a group represented by the formula “—NH—C (═O) —” or a carbonyl group, and a plurality of Y may be the same or different; Is an ethyleneoxy group in which one or more hydrogen atoms may be replaced by an alkyl group or alkyloxyalkyl group in which one hydrogen atom is substituted, and a plurality of Z may be the same or different from each other Even J and k are each independently 0 or 1, and a plurality of j or k may be the same or different from each other; l and m are each independently an integer of 0 or more, and a plurality of l or m may be the same or different from each other; when l is an integer of 2 or more, one Z may be the same or different from each other.

(In the formula, R ³ represents a hydroxyl group or an atom or group that can be substituted with a hydroxyl group; R ⁴ represents a hydrogen atom or a monovalent hydrocarbon group; n is 1, 2 or 3, and n is 2 or 3; And n R ³ may be the same or different from each other; when n is 1, the two R ⁴ may be the same or different from each other.)

R ¹ is a linear or branched perfluoroalkyl group or perfluoroalkyl ether group having ¹ to 16 carbon atoms. Here, the “perfluoroalkyl group” refers to “a group in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms”. The “perfluoroalkyl ether group” refers to “a monovalent group in which the perfluoroalkyl group is bonded to an oxygen atom”.
Examples of the alkyl in R ¹ include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, Examples include tetradecyl, pentadecyl, and hexadecyl.
R ¹ preferably has 3 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms.
R ¹ is preferably linear and is preferably a perfluoroalkyl group.

R ¹ ′ represents a group obtained by removing one fluorine atom from a linear or branched perfluoroalkyl group or perfluoroalkyl ether group having ^{1 to} 16 carbon atoms. Specifically, a divalent group in which one fluorine atom is removed from R ¹ can be exemplified. When R ¹ ′ has 2 or more carbon atoms, one fluorine atom bonded to the terminal carbon atom opposite to the carbon atom bonded to “Z” of R ¹ is removed. Divalent groups are preferred.

R ² is any of the groups represented by the formulas (11) to (16). Then, a plurality of R ² may be the same or different from each other, for example, Compound (2) R ² of both molecular ends in the may be the same or different from each other, the compound R ² in the compound (1) ( R ² in 2) may be the same as or different from each other.

R ³ represents a hydroxyl group or an atom or group that can be substituted with a hydroxyl group.
Preferable examples of the atom capable of substituting for the hydroxyl group of R ³ include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, and chlorine atom is particularly preferable.
Moreover, as a group which can be substituted by a hydroxyl group, a C1-C6 alkoxy group, an aryloxy group, an aralkyloxy group, and an acyloxy group are mentioned as a preferable thing.
Examples of the alkoxy group having 1 to 6 carbon atoms include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, pentoxy group and hexyloxy. Examples are groups.
Examples of the aryloxy group include a phenoxy group and a naphthoxy group.
Examples of the aralkyloxy group include a benzyloxy group and a phenethyloxy group.
Examples of the acyloxy group include an acetoxy group, a propionyloxy group, a butyryloxy group, a valeryloxy group, a pivaloyloxy group, and a benzoyloxy group.
Among these, as R ³ , a chlorine atom, a methoxy group, and an ethoxy group are more preferable, and a chlorine atom is particularly preferable.

R ⁴ represents a hydrogen atom or a monovalent hydrocarbon group.
The monovalent hydrocarbon group for R ⁴ is not particularly limited, and may be a chain structure or a cyclic structure, and may be either saturated or unsaturated. In the case of a chain structure, either a straight chain or a branched chain may be used, and in the case of a cyclic structure, either a monocyclic structure or a polycyclic structure may be used.
Among these, preferred are an alkyl group having 1 to 6 carbon atoms, an aryl group, and an aralkyl group.
Examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group and hexyl group. It can be illustrated.
Examples of the aryl group include a phenyl group and a naphthyl group.
Examples of the aralkyl group include a benzyl group and a phenethyl group.
Among these, as R ⁴ , a methyl group, an ethyl group, an n-propyl group, and an isopropyl group are more preferable, and a methyl group is particularly preferable.

Y is a group represented by the formula “—NH—C (═O) —” or a carbonyl group. That is, adjacent methylene groups and oxygen atoms are bonded as follows.
“— (CH ₂ ) _m — (NH—C (═O)) _j — (O) _k —”
_{"- (CH 2) m - (} C (= O)) j - (O) k - "
A plurality of Y may be the same as or different from each other. For example, Ys facing each other across “R ¹ ′” in the compound (2) may be the same as or different from each other. ) In Y) and Y in compound (2) may be the same as or different from each other.

Z is an ethyleneoxy group in which one hydrogen atom is substituted for an alkyl group or an alkyloxyalkyl group in which one or more hydrogen atoms may be substituted with a fluorine atom. The terminal oxygen atom of the ethyleneoxy group is bonded to the adjacent R ¹ .
The number of hydrogen atoms that may be substituted in the ethyleneoxy group is preferably one. Further, the alkyl group or alkyloxyalkyl group in which one or more hydrogen atoms may be substituted with a fluorine atom is preferably linear or branched, and more preferably linear. . And it is preferable that carbon number is 1-16.
A plurality of Z may be the same as or different from each other. For example, in the compound (2), Zs facing each other across “R ¹ ′” may be the same as or different from each other. ) In Z) and Z in compound (2) may be the same or different.

j and k are each independently 0 or 1, and particularly preferably 0. Moreover, several j or k may mutually be same or different. For example, j relating to Y facing each other across “R ¹ ′” in compound (2) may be the same or different from each other, and j relating to Y in compound (1) may be different from that in compound (2). J for Y may be the same as or different from each other. The same applies to k.

l and m are each independently an integer of 0 or more.
L is particularly preferably 0.
m is preferably 0 to 3, more preferably 1 or 2, and particularly preferably 2.
A plurality of l or m may be the same as or different from each other. For example, in the compound (2), ^{1's related} to Z facing each other across “R ¹ ′” may be the same as or different from each other, and the 1's related to Z in the compound (1) and the 1 The l's corresponding to Z may be the same as or different from each other. The same applies to m.
Furthermore, when l is an integer greater than or equal to 2, 1 Z may mutually be same or different.

n is 1, 2 or 3, and when n is 2 or 3, n R ^{3 s} may be the same or different from each other, and when n is 1, two R ⁴ May be the same or different from each other.

  As a compound (1) or (2), what is represented by the following general formula (3) or (4) is mentioned as a more preferable thing.

(In the formula, R ¹ , R ¹ ′, R ² and m are the same as described above.)

In the general formula (1) or (2), a compound in which Z is represented by “— (CHR ⁵ —CHR ⁶ —O) _{1 ′} — (CHR ⁷ —CHR ⁸ —O) ₁ ″” It is mentioned as a more preferable thing.
Here, one of R ⁵ and R ⁶ represents a hydrogen atom, and the other represents one hydrogen atom of a methyl group in a linear or branched fluoroalkyl group or fluoroalkyl ether group having 1 to 16 carbon atoms. Represents a substituted group. Here, the “fluoroalkyl ether group” refers to “a monovalent group in which the linear or branched fluoroalkyl group having 1 to 16 carbon atoms is bonded to an oxygen atom”.
One of R ⁷ and R ⁸ represents a hydrogen atom, and the other represents a linear or branched alkyl group or alkyl ether group having 1 to 16 carbon atoms. Here, the “alkyl ether group” refers to “a monovalent group in which the linear or branched alkyl group having 1 to 16 carbon atoms is bonded to an oxygen atom”.

l ′ is an integer of 2 or more, preferably 2 to 20, and more preferably 5 to 10.
l ″ is an integer of 0 or more, preferably 0 to 20, and more preferably 0.

Examples of the fluoroalkyl group in which one hydrogen atom of the methyl group in R ⁵ and R ⁶ is substituted include CF ₃ —, CHF ₂ —, CClF ₂ —, C ₂ F ₅ —, CHF ₂ CF ₂ —, CClF. _{2 CF 2 -, (CF 3} ) 2 CF-, CF 3 CF 2 CF 2 -, (CHF 2) 2 CF -, (CF 3) (CHF 2) CF -, (CF 3) 2 CFCF 2 CF 2 - _{, (CF 3) 2 CF (} CF 2 CF 2) 2 -, CF 3 (CF 2) 3 -, CF 3 (CF 2) 5 -, CF 3 (CF 2) 7 -, CF 3 (CF 2) 9 _{-, CF 3 (CF 2)} 11 -, CF 3 (CF 2) 13 -, CF 3 (CF 2) 15 - it can be exemplified.
And in R ⁵ and R ^6, examples of the fluoroalkyl ether group in which one hydrogen atom is substituted methyl group, a monovalent group such fluoroalkyl groups linked to an oxygen atom can be exemplified.

Examples of the alkyl group for R ⁷ and R ⁸ include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, Examples include dodecyl, tridecyl, tetradecyl, pentadecyl and hexadecyl.
The Examples of the alkyl ether groups in R ⁷ and R ^8, monovalent radicals the alkyl groups linked to an oxygen atom can be exemplified.

As described above, the liquid repellent layer can be formed by bonding a liquid repellent treatment agent to the substrate. A commercially available product may be used as the liquid repellent treatment agent.
For example, when the substrate surface has a hydroxyl group, the compound (1) or (2) having a group represented by R ² represented by the formula (11), (12) or (16) is used. It is preferable to do.
Among these, the compound (1) or (2) having an organic silyl group represented by the formula (16) or the like is preferable because it is easy to obtain a commercial product. Examples of such commercially available products include CYTOP series (trademark, manufactured by Asahi Glass Co., Ltd.), MegaFuck (trademark, manufactured by Dainippon Ink Chemical Co., Ltd.), and Dick Guard (trademark, manufactured by Dainippon Ink Chemical Co., Ltd.). ), FPX-30G (trademark, manufactured by JSR Corporation), Novec EGC-1720 (trademark, manufactured by Sumitomo 3M Corporation), Patinal series (substance WR1, WR2, WR3) (trademark, manufactured by Merck Corporation), OPTOOL DSX ( Trademark, manufactured by Daikin Industries, Ltd.).

When R ² has a group other than the above formulas (11), (12) and (16), for example, a group represented by the above formula (13), (14) or (15) The substrate surface may be treated so as to have a functional group capable of reacting with these groups.
For example, according to the method described in Chembiochem, 2,686-694 (2001) (Benters R. Et al.), A compound having a group represented by the formula (14) as R ² (that is, an amino group) (1) or (2) can be bonded to the substrate.
Further, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 3- (2-aminoethylamino) propyltrimethoxysilane, 3- (2-aminoethyl) If an organic silane compound having an amino group such as amino) propyltriethoxysilane or 3- (2-aminoethylamino) propyldimethoxymethylsilane is bonded to the substrate surface, R ² is represented by the formula (13). The compound (1) or (2) having a group (that is, a carboxyl group) or a group represented by the formula (15) (that is, an epoxy group) can be bonded to the substrate. The organosilane compound is easily available.

In the liquid repellent layer, the liquid repellent treatment agent is such that at least a part of the molecule, preferably one end of the molecule is bonded to a specific atom or functional group on the substrate, while the liquid repellent portion is directed to the outside of the substrate. It is assumed that it is oriented so as to be exposed. For example, when the compound (1) is used as a liquid repellent treatment agent, the R ² is bonded to the substrate while the R ¹ is oriented so as to be exposed toward the outside of the substrate. Further, when the compound (2) is used, it is presumed that one or two R ² bonds to the substrate, while R ¹ ′ is oriented so as to be exposed to the outside of the substrate.
Thus, it is estimated that the liquid-repellent layer exhibits a liquid-repellent effect by orienting the liquid-repellent portions. Therefore, by using a compound having a perfluoroalkyl group or a perfluoroalkyl ether group like the compound (1) or (2), it becomes possible to develop a higher liquid repellency effect on the substrate.

  In addition, the liquid repellent layer formed using the compound (1) or (2) has better transparency than a conventional layer containing polytetrafluoroethylene and is suitable for forming a thin single-layer thin film. Excellent in fine workability such as patterning and removal. Since the transparency is excellent, for example, when a cell or a substance is optically measured, noise can be greatly reduced, and highly sensitive analysis is possible. In addition, since the fine workability is excellent, a large number of minute unmodified portions 102 or 202 can be formed on the substrate 11 or 12 as described above. Thereby, since the arrangement density of the analysis object on the surface modification board | substrate 1 or 2 can be made high, it can analyze with high efficiency.

The liquid repellent agent in the liquid repellent layer may be one kind or two or more kinds. When two or more types are used in combination, the combination, ratio, and the like can be appropriately selected depending on the purpose.
In addition, the liquid repellent layer may contain any component other than the liquid repellent agent as long as the effects of the present invention are not hindered.

  The thickness of the liquid repellent layer is preferably adjusted as appropriate according to the use of the substrate. For example, in the case of various cell array chips, it is usually preferably 100 nm or less, more preferably 50 nm or less, and particularly preferably 10 nm or less. By setting it as such a range, a liquid repellent layer becomes the thing excellent in fine workability. Furthermore, for example, a cell array chip that can be analyzed with high sensitivity can be produced. Among these, by using the compound (1) or (2) to form a monomolecular film on the substrate surface, the thickness of the liquid repellent layer can be reduced to 10 nm or less, and particularly excellent effects are exhibited. A surface-modified substrate is obtained.

  According to the present invention, a surface-modified substrate in which the pattern of the concave portion when viewed from above the substrate and the pattern of the non-modified portion that is not covered with the modifying layer is obtained with high accuracy can be obtained. Fine and highly accurate modified patterns and unmodified portions can be formed. And, for example, by using the compound (1) or (2) as a modifier, a liquid repellent layer that is more excellent in fine workability can be formed, and these effects are exhibited synergistically.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.
Example 1
A cell array chip was prepared by the method described in FIG.
That is, as a substrate 11, a glass substrate (thickness: 0.7 mm) of Pyrex (registered trademark) (code 7059, manufactured by Corning International Co., Ltd.) is used, and sputtering is performed on the entire surface 11a by using argon plasma. A chromium thin film having a thickness of 0.3 μm was formed. Then, a photoresist was patterned in a predetermined pattern on the chromium thin film, and this glass substrate was immersed in a chromium etching solution to form a chromium mask as the metal mask 12.
Next, the glass substrate on which the chrome mask is formed is dipped in buffered hydrofluoric acid (BHF), and the glass substrate is etched, so that a recess having X ₁ of 25 μm and Y ₁ of 1 μm has the same shape as FIG. 110 was formed.
Next, ZPN (manufactured by ZEON CORPORATION) as a negative photoresist 13 is applied to the entire surface of the substrate 11 on which the recess 110 is formed, exposed from the substrate back surface 11b side, and the exposed substrate is made into a chromium etching solution. The chrome mask was peeled off by dipping.
Then, OPTOOL DSX (trademark, manufactured by Daikin Industries, Ltd.) as a modifier is dip coated on the entire surface of the glass substrate patterned with resist, dried overnight, then heated at 100 ° C. for 1 hour, and fluorine system solvent (0.02 mol / L of _{CF 3 - (CF 2) 7} - (CH 2) 2 -SiCl 3) a is Novec HFE (TM, manufactured by Sumitomo 3M Limited) by washing using modified A non-cell adhesion layer (liquid repellent layer) was formed as the layer 15. As a result of measuring the thickness of the non-cell adhesion layer with an ellipsometer, it was 4.5 nm.
Next, all the resist on the glass substrate is removed together with the non-cell adhesion layer covering the same to form the recess 110 which is a cell arrangement portion, and the glass substrate surface other than the cell arrangement portion is a non-cell adhesion layer. A coated cell array chip was obtained.

(Example 2)
A cell array chip was prepared by the method described in FIG.
That is, as a substrate 21, a glass substrate (thickness: 0.7 mm) of Pyrex (registered trademark) (code 7059, manufactured by Corning International Co., Ltd.) is used, and sputtering is performed on the entire surface 21a by using argon plasma. An aluminum thin film having a thickness of 0.5 μm was formed. Then, a photoresist was patterned on the aluminum thin film in a predetermined pattern, and this patterning surface was dry etched. Dry etching was performed using a plasma generated from a mixed gas of Cl ₂ , BCl ₂ and CCl ₃ . As a result, an aluminum mask was formed as the metal mask 22.
Next, dry etching was performed to form a recess 210 having the same shape as that shown in FIG. 2 and having X ₂ of 15 μm and Y ₂ of 3 μm. The dry etching conditions at this time are as described above with reference to FIG. 2 and were performed using plasma generated from C ₃ F ₈ gas.
Next, ZPN (manufactured by ZEON Co., Ltd.) is applied as a negative photoresist 23 on the entire surface of the substrate 21 where the recesses 210 are formed, exposed from the substrate back surface 21b side, and generated from a mixed gas in the same manner as described above. The plasma was used for dry etching to peel off the aluminum mask.
Then, a non-cell adhesion layer (liquid repellent layer) is formed as the modification layer 25 on the entire surface of the glass substrate patterned with the resist by a vacuum deposition method using WR1 Partial (trade name, manufactured by Merck Ltd.) as a deposition source. did. At this time, the temperature of the vapor deposition source was 360 ° C. to 450 ° C., and vapor deposition was performed at a vacuum degree of 10 ⁻³ Pa for 30 seconds. Moreover, as a result of measuring the thickness of the non-cell adhesion layer with an ellipsometer, it was about 5 nm.
Next, by removing all the resist on the glass substrate together with the non-cell adhesion layer covering the same, a recess 210 which is a cell arrangement portion is formed, and the surface of the glass substrate other than the cell arrangement portion is a non-cell adhesion layer. A coated cell array chip was obtained.

  The present invention can be used in fields such as cell function research, cell-based bioassay and substance production.

It is sectional drawing for demonstrating an example of the manufacturing process of the surface modification board | substrate of this invention. It is sectional drawing for demonstrating the other example of the manufacturing process of the surface modification board | substrate of this invention. It is sectional drawing for demonstrating an example of the conventional manufacturing process of a surface modification board | substrate. It is sectional drawing for demonstrating the problem in the conventional manufacturing method of a surface modification board | substrate.

Explanation of symbols

1, 2 ... surface modified substrate, 11, 12 ... substrate, 11a, 12a ... substrate surface, 11b, 12b ... substrate back surface, 12, 22 ... metal mask, 110, 120 ... Recess, 13, 23 ... Negative photoresist, 14, 24 ... Exposure light, 13 ', 23' ... Resist layer, 15, 25 ... Modified layer

Claims (5)

A method for producing a surface-modified substrate in which a modification layer is provided on the substrate surface,
Covering a predetermined portion of the substrate surface having light permeability with a metal mask, etching, and forming a recess in the substrate surface;
Coating the entire surface of the substrate with a negative photoresist without removing the metal mask; and
Patterning a resist layer by exposing the negative photoresist from the back side of the substrate and then developing;
Removing the metal mask without removing the resist layer, and then coating the entire surface of the substrate with a modifying agent to provide a modifying layer;
Removing the modification layer on the resist layer together with the resist layer coated with the modification layer;
A method for producing a surface-modified substrate, comprising: From at least one gas selected from the group consisting of CF ₄ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₆ , C ₄ F ₈ , C ₅ F ₈ , CHF ₃ , CH ₂ F ₂ and SF _6. The method for producing a surface-modified substrate according to claim 1, wherein the recess is formed by dry etching using generated plasma.   The method for producing a surface-modified substrate according to claim 1, wherein a liquid repellent treatment agent that exhibits liquid repellency is used as the modifier, and the modification layer is liquid repellant. The method for producing a surface-modified substrate according to claim 3, wherein the liquid repellent agent is a compound represented by the following general formula (1) or (2).

(In the formula, R ¹ represents a linear or branched perfluoroalkyl group or perfluoroalkyl ether group having ^{1 to} 16 carbon atoms; R ¹ ′ represents a linear or branched chain having ^{1 to} 16 carbon atoms; Represents a group in which one fluorine atom is removed from a perfluoroalkyl group or a perfluoroalkyl ether group; R ² is any one of groups represented by the following formulas (11) to (16), and a plurality of R ² may be the same or different; Y is a group represented by the formula “—NH—C (═O) —” or a carbonyl group, and a plurality of Y may be the same or different; Is an ethyleneoxy group in which one or more hydrogen atoms may be replaced by an alkyl group or alkyloxyalkyl group in which one hydrogen atom is substituted, and a plurality of Z may be the same or different from each other Even J and k are each independently 0 or 1, and a plurality of j or k may be the same or different from each other; l and m are each independently an integer of 0 or more, and a plurality of l or m may be the same or different from each other; when l is an integer of 2 or more, one Z may be the same or different from each other.

(In the formula, R ³ represents a hydroxyl group or an atom or group that can be substituted with a hydroxyl group; R ⁴ represents a hydrogen atom or a monovalent hydrocarbon group; n is 1, 2 or 3, and n is 2 or 3; And n R ³ may be the same or different from each other; when n is 1, the two R ⁴ may be the same or different from each other.) The method for producing a surface-modified substrate according to claim 4, wherein the compound represented by the general formula (1) or (2) is represented by the following general formula (3) or (4).

(In the formula, R ¹ represents a linear or branched perfluoroalkyl group or perfluoroalkyl ether group having ^{1 to} 16 carbon atoms; R ¹ ′ represents a linear or branched chain having ^{1 to} 16 carbon atoms; Represents a group in which one fluorine atom is removed from a perfluoroalkyl group or a perfluoroalkyl ether group; R ² is any one of groups represented by the following formulas (11) to (16), and a plurality of R ² may be the same or different; m is an integer of 0 or more, and a plurality of m may be the same or different.

(In the formula, R ³ represents a hydroxyl group or an atom or group that can be substituted with a hydroxyl group; R ⁴ represents a hydrogen atom or a monovalent hydrocarbon group; n is 1, 2 or 3, and n is 2 or 3; And n R ³ may be the same or different from each other; when n is 1, the two R ⁴ may be the same or different from each other.)

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