JP4065962B2 - Fabrication method and utilization of self-assembled monolayer - Google Patents

Description

The present invention relates to a method for producing a self-assembled monolayer. Specifically, the present invention relates to a method for producing a higher quality self-assembled monolayer by a so-called gas phase method. The present invention also relates to a film material having a high-quality self-assembled monolayer.
This application claims priority based on Japanese Patent Application No. 2005-118932 filed on Apr. 15, 2005, the entire contents of which are hereby incorporated by reference.

Self-assembled monolayer (Self-Assembled)
Monolayer, hereinafter also referred to as “SAM”. ) Is known. As a main method of forming a SAM using such a material (hereinafter also referred to as “self-assembled monolayer film forming material” or “SAM forming material”), a method of bringing a solution containing the SAM forming material into contact with a substrate (Liquid phase method). Patent Documents 1 to 3 are cited as prior art documents relating to SAM formation by this type of method. Patent Documents 1 and 2 exemplify alcohols, aromatic hydrocarbons, aliphatic hydrocarbons and the like as the solvent constituting the solution containing the SAM-forming material. Patent Document 3 describes a technique using compressed carbon dioxide as a solvent constituting the solution.

JP 2002-327283 A JP 2001-152363 A JP 2004-315461 A

On the other hand, as another method for forming a SAM on a base material, a method of chemical vapor deposition of a SAM forming material on the base material (sometimes referred to as a vapor phase method or a CVD method) has been proposed. This gas phase method has advantages such that the SAM forming material can be used efficiently, and the amount of waste liquid can be reduced as compared with the liquid phase method, so that the burden on the environment is small.
However, the SAM formed by the vapor phase method tends to be different in quality from the SAM formed by the liquid phase method. For example, a SAM formed by a vapor phase method tends to have a lower film density and / or orientation of a SAM forming material than a SAM formed by a liquid phase method. For this reason, the desired property (for example, water repellency) expected from the property of the SAM formed by the liquid phase method may not be sufficiently exhibited.

  Accordingly, an object of the present invention is to provide a method for producing a higher quality SAM by a vapor phase method. For example, an object of the present invention is to provide a method for producing a SAM exhibiting properties (for example, the size of a contact angle) similar to that of a SAM formed by a liquid phase method by a gas phase method. Another object of the present invention is to provide a film material having such a high quality SAM.

  In the chemical vapor deposition of the SAM forming material on the substrate, the present inventor improves the quality of the SAM obtained by the vapor deposition by appropriately controlling predetermined conditions (for example, forming a higher density SAM). The present invention was completed.

  In accordance with the present invention, a method is provided for making a SAM on a substrate by chemical vapor deposition of a SAM-forming material on the substrate. In the method, during chemical vapor deposition, (1) the atmospheric gas humidity (relative humidity at 25 ° C.) is set to 30% or less. (2) The ambient temperature is 60 ° C. or higher. Further, (3) The surface temperature of the base material at the time of starting the vapor deposition is made higher than room temperature. By performing chemical vapor deposition (typically, thermal CVD) so as to satisfy all of the above (1) to (3), a SAM with higher quality (for example, higher density) can be formed. For example, compared with a SAM formed by a liquid phase method using the same type of SAM forming material, a SAM having properties closer to the liquid phase method SAM (for example, a contact angle) can be produced. If the atmospheric gas humidity is too much higher than the above range, the density of the obtained SAM tends to be low, and it becomes difficult to obtain a SAM exhibiting the expected properties.

The “density” of the SAM is determined when the arrangement of substances constituting the SAM (which can also be regarded as a reaction residue of the SAM forming material) in the region where the SAM is formed in the base material is examined in detail. It can also be grasped as the ratio of the area where the substrate is covered with the above substance, that is, the “covering ratio” of the substrate with the SAM constituent material. Higher coverage corresponds to higher SAM density (arrangement density or packing density on the substrate).
The said coverage can be evaluated using the water droplet contact angle of the surface in which SAM is formed. More specifically, on the surface composed of two different types of components A and B, the areas occupied by these components A and B are Q ₁ and Q ₂ , respectively. Assuming that the water droplet contact angle on the surface and the ideal water droplet contact angle on the surface composed of component B are θ ₁ and θ ₂ , respectively, the water droplet contact angle θ on the surface composed of these two components and the occupied areas Q ₁ , Q ₂ and The following relational expression (i) holds between the water droplet contact angles θ ₁ and θ ₂ (Cassie-Baxter's expression).
cosθ = Q ₁ cosθ ₁ + Q ₂ cosθ ₂ (i)
The coverage can be calculated from this relational expression. As the value of the ideal water droplet contact angle of the component A, when the component A is the substrate surface, the value of the water droplet contact angle of the substrate surface itself can be adopted as θ _1. . In addition, when the component A is a SAM, a value of “expected contact angle” for the SAM (details will be described later), for example, a SAM formed almost ideally by a general liquid phase method. The value of the water droplet contact angle that is theoretically derived from the water droplet contact angle or the chemical structure of the SAM (typically based on the surface energy of the SAM) can be used as θ ₁ .
According to the method disclosed herein, a high-density SAM having a coverage of approximately 80% or more can be produced. In a more preferable embodiment, a SAM having the above-mentioned coverage of approximately 85% or more (in a more preferable embodiment, approximately 90% or more, for example, about 90 to 98%) can be produced. Therefore, another aspect of the invention disclosed herein is a SAM manufacturing method for obtaining such a high coverage (or high density) SAM.

  In a preferred embodiment of the method disclosed herein, the relative humidity at 25 ° C. of the atmospheric gas is 5 to 30%. As a result, a SAM with higher quality (for example, higher density) can be obtained, and the quality of the obtained SAM can be stabilized, and a high-quality SAM can be formed at a wider ambient temperature (ie, the ambient temperature One or more effects can be realized. When alkoxysilane (for example, trimethoxysilane) is used as the SAM forming material, it is particularly effective to form SAM under the humidity condition selected from the above range. The humidity of the atmospheric gas (relative humidity at 25 ° C., hereinafter the same) is preferably 5 to 25%, more preferably 7 to 20%.

  In another preferable embodiment of the method disclosed herein, the ambient temperature is set to 100 to 200 ° C. (more preferably 100 to 180 ° C.). Thereby, it is possible to obtain a SAM of higher quality (higher density). When alkoxysilane (for example, trimethoxysilane) is used as the SAM forming material, it is particularly effective to form SAM under an atmospheric temperature selected from the above range.

  In another preferred embodiment of the method disclosed herein, the surface temperature of the substrate at the time of starting the vapor deposition (hereinafter sometimes referred to as “initial substrate temperature”) is set to 50 ° C. or higher. The temperature is more preferably 60 ° C. or higher, and further preferably 80 ° C. or higher. By setting the initial substrate temperature within the above range, at least one of the effects of forming a SAM having better quality (for example, higher density) and stabilizing the quality of the obtained SAM can be obtained.

  The SAM production method disclosed herein is particularly preferably applied when alkoxysilane is used as the SAM forming material. That is, it is preferably applied to the production of a SAM using a SAM-forming material that is a compound capable of forming SAM on the substrate surface and has at least one alkoxy group (alkoxysilyl group). The number of alkoxy groups contained in the SAM forming material is preferably 2 or 3 (that is, dialkoxysilane or trialkoxysilane), particularly preferably those having three alkoxy groups. It is preferable that carbon number of an alkoxy group is 1-4, More preferably, it is 1-3.

One preferred example of the SAM-forming material used in the method disclosed herein is an alkoxysilane having at least one alkoxy group and a relatively long carbon chain that is substituted or unsubstituted. For example, a SAM forming material in which the carbon chain is an aliphatic group having 10 or more carbon atoms (typically 10 to 30) is preferable. The aliphatic group may be saturated or unsaturated, and may be linear or branched. The aliphatic group may be an open chain or an alicyclic group in which at least a part forms a non-aromatic ring.
Another example of a preferable SAM-forming material is an alkoxysilane having at least one alkoxy group and an aromatic group containing a substituted or unsubstituted aromatic ring. For example, a compound in which a substituted or unsubstituted aryl group or alkylaryl group is bonded to silicon (Si) (phenylalkoxysilane, benzylalkoxysilane, methylphenyltrimethoxysilane, or a substituted product thereof) is preferable. .

  In producing a SAM on a substrate by applying the method disclosed herein, a substrate that has been subjected to a predetermined pretreatment can be preferably used. The pretreatment includes, for example, (A). Hydrogen-termination of the surface of at least a portion of the base material where SAM is to be formed. And (B). Introducing a functional group containing oxygen as a constituent atom (for example, a hydroxyl group) into the hydrogen-terminated base material surface. By using a base material that has been subjected to such pretreatment, a high-quality (for example, high-density) SAM can be more appropriately produced on the base material.

  For example, when a SAM is produced on a silicon substrate (base material) by applying the method disclosed herein, a silicon substrate that has been subjected to a predetermined pretreatment can be preferably used. The pretreatment includes hydrogen termination of the surface of the silicon substrate (for example, (111) plane). In addition, a functional group containing oxygen (for example, a hydroxyl group) is introduced into the hydrogen-terminated substrate surface. The silicon substrate obtained by performing such pretreatment may have a highly planarized surface (typically at the atomic level). Moreover, the functional group containing oxygen may be appropriately (for example, more uniformly) introduced on the surface. Such a surface is suitable for better depositing the SAM-forming material. Therefore, a well-organized (aligned) monomolecular film can be formed on the surface (for example, (111) plane) of the silicon substrate. That is, by using the silicon substrate that has been subjected to the above pretreatment, a higher quality (for example, higher density) SAM can be formed on the substrate.

As a suitable method for introducing the functional group, vacuum ultraviolet light (Vacuum Ultra Violet; hereinafter) is used in an atmosphere containing oxygen (typically oxygen molecules (O ₂ )) on the surface of the hydrogen-terminated substrate. A method of irradiating with “VUV” is also exemplified. For example, by irradiating the surface of the substrate with VUV in an atmosphere of reduced pressure (for example, about 1 Pa to 1500 Pa, preferably about 10 Pa to 1000 Pa), a functional group (such as a hydroxyl group) containing oxygen as a constituent atom is appropriately applied to the substrate surface. Can be introduced. This makes it possible to prepare a substrate that is flat and has a surface that is suitable for depositing a SAM-forming material.

  According to the present invention, there is also provided a membrane material comprising a substrate and a SAM formed on the substrate. The SAM may be a high density film having a coverage of about 85% or more (preferably about 90% or more). The SAM may be a film prepared by chemical vapor deposition of a SAM forming material on the substrate. Since such a film material has a high coverage (ie, high density) SAM, characteristics of the film (for example, characteristics expected from the molecular structure of the SAM forming material) can be more appropriately exhibited. . For example, it may exhibit good water repellency, hydrophilicity, lubricity and the like. Moreover, it may be excellent in the protection performance of the substrate.

Thus, a high-density SAM is suitable for forming a high-precision (for example, high-definition and high-shape accuracy) pattern. In a preferred embodiment of the film material disclosed herein, the SAM is formed in a predetermined pattern.
In the present specification, the “pattern” refers to a portion of the surface of the base material in any form (shape and / or pattern) that can be distinguished from other portions by forming a specific SAM. The configuration of the portion where the specific SAM is not formed, that is, the “other portion” is not particularly limited. For example, it may be a portion where the substrate surface is exposed, or may be a portion having a material (metal plating layer, glass coating, etc.) other than SAM on the substrate, which is different from the specific SAM. (For example, the chemical structure of the tail group (the presence or absence of a functional group and its type, etc.) may be different).
Since the film material includes a high-density (high filling rate) SAM, the film material can be excellent in the clarity of the boundary between the portion where the SAM is formed and the other portion (that is, the outer edge of the SAM). .

  The film material having a SAM formed in a predetermined pattern as described above may be a film material further provided with another material applied in a form corresponding to the pattern of the SAM. For example, it may be a film material in which another layer (metal plating layer or the like) is selectively formed on the SAM pattern. Alternatively, a film material in which other layers (resin coating layer, solder layer, etc.) are selectively formed on the portion excluding the SAM pattern (in a form reverse to the SAM pattern) may be used. A film material having a plating layer (for example, a metal plating layer formed by an electroless plating method) selectively on the SAM pattern is a preferred example of the film material disclosed herein.

  According to the present invention, there is provided a self-assembled monolayer production apparatus for any of the above-described SAM production methods. The apparatus includes a reaction vessel with a gas inlet and a gas outlet. Atmospheric temperature control means for controlling the atmospheric temperature in the reaction vessel is provided. Moreover, a humidity control means for controlling the humidity (humidity of the atmospheric gas) in the reaction vessel is provided. Moreover, the substrate temperature adjusting means for adjusting the temperature of the substrate disposed in the reaction vessel is provided. In addition, a raw material gas supply means for supplying a gas containing the self-assembled monolayer forming material into the reaction vessel from the gas inlet is provided. The apparatus having such a configuration is suitable for carrying out the SAM manufacturing method.

  The atmosphere temperature control means may include a thermocouple as a substrate temperature detector (thermometer), a heater as a substrate heating means, and the like. The humidity control means includes a humidity detection means (hygrometer) that measures the humidity of the atmospheric gas in the reaction vessel, and a gas composition adjustment mechanism that adjusts the composition of the gas flowing into the reaction vessel according to the detection result by the detection means ( And a switching valve for adjusting the mixing ratio of the source gas and the carrier gas. The substrate temperature adjusting means may include a thermocouple as a substrate temperature detector (thermometer), a heater as a heater, and the like. In one preferred embodiment of the apparatus disclosed herein, a substrate mounting table containing at least one (preferably both) of a substrate temperature detector and a substrate heater is provided inside the reaction vessel. . The raw material gas supply means includes a raw material holding container for holding a self-assembled monomolecular film forming material, a heater (heater, etc.) for heating and vaporizing the film forming material, and introducing the film forming material into the reaction container. A carrier gas source for supplying a carrier gas (for example, nitrogen gas) to be used may be included.

Further, the invention disclosed by this specification includes the following.
(1) A method in which a SAM is formed on a silicon substrate by chemical vapor deposition of a SAM forming material. The manufacturing method includes a step of preparing a silicon substrate, a step of performing a pretreatment on the silicon substrate, and a step of chemically depositing a SAM forming material on the pretreated silicon substrate. Here, the step of pre-processing the silicon substrate includes hydrogen-termination of the surface of the silicon substrate. Further, it includes introducing a functional group containing oxygen as a constituent atom into the hydrogen-terminated substrate surface. Such functional groups can be introduced, for example, by irradiating a hydrogen-terminated silicon substrate with vacuum ultraviolet light in an oxygen-containing atmosphere.
(2) In the method of (1), the chemical vapor deposition of the SAM forming material is performed under the same conditions as any of the SAM manufacturing methods described above. For example, an atmospheric gas having a relative humidity of 5 to 30% at 25 ° C. is used; the atmospheric temperature is 100 to 200 ° C .; and the surface temperature of the silicon substrate at the start of deposition is 50 ° C. or higher. It is preferable to perform chemical vapor deposition.

  According to the technique disclosed herein, a high-quality SAM can be produced on a substrate surface by chemical vapor deposition (vapor phase method). Therefore, this technology can be applied to substrates of various sizes and relatively complicated shapes from small to large, with good utilization efficiency of SAM forming materials, low environmental impact ( It is a highly useful and practical technique that can exhibit one or more effects among those that are easy to produce (SAM). Moreover, since the SAM produced by the method disclosed herein or the SAM constituting the film material disclosed herein has a high density (high coverage), it has good water repellency, hydrophilicity, lubricity, etc. May be shown.

FIG. 1 is an explanatory diagram showing a temperature profile of a silicon substrate during sample preparation in Example 1. FIG. FIG. 2 is a graph showing the contact angle of the SAM fabricated according to Example 2. FIG. 3 is a graph showing the contact angle of the SAM produced by Example 3. FIG. 4 is a graph showing the contact angle of the SAM produced according to Example 4. FIG. 5 is a graph showing the contact angle of the SAM fabricated according to Example 5. FIGS. 6A, 6B, and 6C are shape images obtained by AFM of the SAM pattern produced in Example 6, respectively. FIGS. 7A, 7B, and 7C are shape images obtained by AFM of the SAM pattern produced in Example 7, respectively. FIG. 8 is a schematic diagram showing an outline of one configuration example of the SAM manufacturing apparatus. FIG. 9 is a schematic process diagram illustrating an example of a SAM manufacturing method. 10 (1), (2), and (3) are schematic cross-sectional views showing an example of a process for producing a film material according to Example 8. FIG. FIG. 11 is a schematic cross-sectional view showing an example of a process for producing a film material according to the eighth embodiment. 12 (1), 12 (2) and 12 (3) are schematic cross-sectional views showing an example of a process for producing a film material according to Example 8. FIG. FIG. 13 is a schematic process diagram showing a process of producing a film material according to Example 9. FIG. 14 is an SEM image of the film material obtained in Example 9. FIG. 15 is an optical micrograph of the film material obtained in Example 9.

  Hereinafter, specific embodiments relating to the present invention will be described, but the present invention is not intended to be limited to the specific examples. In addition, technical matters other than those specifically mentioned in the present specification and matters necessary for carrying out the present invention (for example, methods for obtaining or synthesizing various SAM-forming materials, adjusting the temperature of the substrate surface) The means and the method for measuring the temperature, the configuration and operation method of the heating apparatus used for the CVD, etc. can be understood as design matters of those skilled in the art based on the prior art. The present invention can be carried out based on the technical contents disclosed in the present specification and drawings and the common general technical knowledge in the field.

  The method of the present invention can be applied to the formation of self-assembled monolayers on various substrates using a so-called gas phase method. The material of the base material to be used is not particularly limited as long as it maintains a solid state at the atmospheric temperature when chemical vapor deposition is performed. For example, one or two selected from silicon (Si), glass, metal (copper, aluminum, germanium, etc.), ceramic (alumina, silica, silicon carbide, etc.), polymer material, carbon material (graphite, diamond, etc.), etc. A base material mainly composed of the above materials can be used. The polymer material can be various thermoplastic resins or thermosetting resins. For example, acrylic resin such as polymethyl methacrylate, epoxy resin, polyamide, aramid (aromatic polyamide), polyimide, ABS resin, polyethylene, polypropylene, polystyrene, polycarbonate, polyethylene terephthalate (PET), phenol resin, urea resin, melamine resin, etc. Are mentioned as suitable polymer materials. A particularly preferable base material for the present invention is a base material (silicon substrate) substantially made of silicon. At least the surface portion (surface portion on which the SAM is formed) may be a base material substantially made of silicon.

In the present invention, the term “self-assembled monolayer (SAM)” refers to a single molecule in which raw material molecules are assembled and autonomously assembled on the surface of a substrate (an interface between a solid and a liquid or an interface between a solid and a gas). A membrane (a membrane formed by a single molecule). However, even if a part of the resulting film is unexpectedly (unintentionally) not a monomolecular film (for example, a bilayer), at least mainly SAM. Applying the manufacturing method of the present invention with the intention of manufacturing can be included in the technical scope of the present invention.
The “self-assembled monolayer forming material” refers to a material capable of forming a self-assembled monolayer on the surface of a substrate. Such a material (SAM-forming material) typically has at least one functional group (head group) that can be adsorbed to the substrate by chemical bonding with the surface of the substrate, and conversely, on the outside of the substrate. It is a molecule (raw material molecule) having at least one tail group extending toward the surface. In general, a SAM formed by high-density adsorption of head groups of raw material molecules on the surface of a base material tends to have highly oriented tail groups of the raw material molecules. A SAM having such a structure is preferable because it can better exhibit characteristics according to the type of raw material molecules.

As the SAM forming material, for example, a compound having a structure in which the head group and the tail group are bonded to a core atom such as silicon (Si) or titanium (Ti) can be used. A compound (organosilicon compound) in which the core atom is silicon is particularly preferable.
The head group can be an alkoxy group or a halogen atom. Particularly preferred head groups for the present invention include alkoxy groups (alkoxysilyl groups and the like). For example, an alkoxy group having 1 to 4 carbon atoms (more preferably 1 to 3 carbon atoms) is preferable. A methoxy group or an ethoxy group is more preferable, and a methoxy group is usually most preferable. A compound having two or more (typically two or three) head groups in one molecule is preferable, and a compound having three head groups is more preferable. In the SAM forming material having a plurality of head groups, these head groups may be the same or different, but usually a compound having a plurality of the same head groups is preferred. Examples of preferable SAM forming materials include compounds having a structure in which three alkoxy groups and one tail group are bonded to a silicon atom as a core atom (trimethoxysilane, triethoxysilane, etc.).

  The tail group of the SAM-forming material is, for example, a substituted or unsubstituted aliphatic group or aromatic group (a group having a structural portion exhibiting aromaticity. Typically, the tail group includes at least one aromatic ring. Group). The aliphatic group may have, for example, 1 to 30 carbon atoms (more preferably 3 to 30 carbon atoms, still more preferably 5 to 30 carbon atoms). The aromatic group may have, for example, 5 to 30 (more preferably 6 to 30) carbon atoms. A part of carbon atoms constituting such an aliphatic group (typically, carbon atoms constituting the main chain of the aliphatic group) is replaced with a hetero atom (nitrogen atom, oxygen atom, sulfur atom, etc.). Or a part of carbon atoms constituting the aromatic group (typically carbon atoms constituting the aromatic ring) are replaced by heteroatoms (nitrogen atom, oxygen atom, sulfur atom, etc.) Also good.

  An example of a preferable tail group is an aliphatic group having 10 or more carbon atoms (typically 10 to 30). This aliphatic group may be saturated or unsaturated, and may be linear or branched. Further, the aliphatic group may be an open chain, and at least a part thereof may form a non-aromatic ring (for example, a cyclohexyl ring). For example, a linear aliphatic group having 10 to 30 carbon atoms (typically, a hydrocarbon group such as an alkyl group, an alkenyl group, or an alkynyl group) is preferable. A linear alkyl group having 10 to 30 carbon atoms is particularly preferred. N-octadecyltrimethoxysilane used in Examples described later is one specific example of the SAM-forming material having such a tail group. A tail group having a structure in which part or all of the hydrogen atoms constituting the aliphatic group are replaced with halogen atoms (fluorine atoms, chlorine atoms, etc.) is also preferable. For example, it is preferable that a majority of the hydrogen atoms constituting the aliphatic group (for example, 70% by number or more hydrogen atoms) are replaced with fluorine atoms. Heptadecafluoro-1,1,2,2-tetrahydrodecyltrimethoxysilane used in Examples described later is a specific example of a SAM-forming material having such a tail group.

  Another example of a preferable tail group is a saturated or unsaturated group having 2 or more carbon atoms (typically 2 to 9 carbon atoms, for example 3 to 6 carbon atoms) having a substituent at least at the terminal (opposite side to the core atom). Saturated aliphatic groups are mentioned. The substituent may be, for example, a substituted or unsubstituted amino group, mercapto group, hydroxyl group, carboxyl group, aldehyde group, sulfonic acid group, cyano group, halogen atom and the like. 3-Mercaptopropyltrimethoxysilane used in Examples described later is one specific example of the SAM-forming material having such a tail group.

  Another example of a preferred tail group is an aromatic group containing at least one substituted or unsubstituted aromatic ring (typically a benzene ring). An aromatic group having 5 or more carbon atoms (typically 5 to 30) is preferable, and an aromatic group having 6 to 20 carbon atoms is more preferable. The tail group can be, for example, a substituted or unsubstituted aryl group or an alkylaryl group. A tail group having a structure in which part or all of the hydrogen atoms constituting such an aromatic group are replaced with halogen atoms (fluorine atoms, chlorine atoms, etc.) is also preferred. Moreover, this aromatic group may have a substituent other than a halogen atom. Such substituents include saturated or unsaturated substituted or unsubstituted hydrocarbon groups having about 1 to 12 carbon atoms (methyl group, ethyl group, chloromethyl group, etc.), unsubstituted amino groups, or substituted Illustrative examples include amino groups (mono- or dialkylamino groups such as dimethylamino group), fluoro groups and the like. Specific examples of the SAM-forming material having such a tail group include p-aminophenyltrimethoxysilane and p-chloromethylphenyltrimethoxysilane used in Examples described later.

  In the SAM manufacturing method disclosed herein, a SAM forming material (raw material molecules) is vapor-deposited on a substrate under an atmospheric gas having a predetermined humidity. Here, the “atmospheric gas” refers to a vapor deposition space (for example, in a reaction vessel) when source molecules are vapor-deposited on the substrate surface (that is, when gaseous source molecules are deposited from the gas phase to the substrate surface). ) Satisfies gas. As the main component of the atmospheric gas, it is preferable to use a gas having low reactivity with respect to the SAM forming material or the substrate surface. For example, an inert gas such as nitrogen gas or argon gas can be preferably used. This atmospheric gas contains water molecules (water vapor) at a concentration corresponding to a predetermined humidity. The “predetermined humidity” is preferably about 30% or less (typically about 5 to 30%) in terms of relative humidity (RH) at 25 ° C. The predetermined humidity is more preferably about 7 to 25%, and further preferably about 7 to 20%. For example, in the case of an atmospheric gas containing nitrogen gas as a main component, the humidity can be adjusted by mixing water vapor alone into the dry nitrogen gas. Further, a gas having a humidity higher than the target value (for example, air) may be mixed in the dry nitrogen gas.

  In the method disclosed herein, source molecules are vapor-deposited on a substrate under a predetermined atmospheric temperature. Here, “atmosphere temperature” refers to the environmental temperature at which raw material molecules are deposited on the substrate surface. When the substrate is brought into the ambient temperature from the outside, the ambient temperature and the temperature of the substrate may be different for a while immediately after the introduction of the substrate, but for a while (for example, 30 minutes or more) based on the ambient temperature. The temperature of the held substrate (at least the temperature of the substrate surface) can be substantially the same as the ambient temperature. The ambient temperature is suitably at least about 60 ° C. or higher, and is usually preferably about 100 to 200 ° C., more preferably about 100 to 180 ° C. If the ambient temperature is too lower than 60 ° C., the raw material molecules that have reached the substrate surface will not easily move around the substrate surface. For this reason, it becomes difficult to appropriately advance the SAM formation process in which the raw material molecules are autonomously organized by finding a position that is more energetically advantageous than other parts on the surface of the base material and adsorbing the position. , SAM quality (for example, density) tends to decrease.

In the SAM manufacturing method disclosed herein, at the time of starting the deposition of the SAM forming material, at least the surface temperature (initial substrate temperature) of the substrate is controlled (hereinafter, unless otherwise specified, the surface temperature of the substrate). And the internal temperature are generally equal to each other and are simply referred to as “substrate temperature” or “initial substrate temperature”). The initial substrate temperature is preferably about 50 ° C. or higher, more preferably 70 ° C. or higher. Moreover, it is preferable that the initial substrate temperature is not too higher than the ambient temperature. For example, the atmospheric temperature is preferably + 20 ° C. or lower (more preferably atmospheric temperature + 10 ° C. or lower, more preferably the same or lower than the atmospheric temperature). In a preferred embodiment, the initial substrate temperature (Ts) is about 50 ° C. or higher (more preferably about 60 ° C. or higher), and Tv-80 in relation to the atmospheric temperature (Tv) during deposition. The temperature is set so as to satisfy C ≦ Ts ≦ Tv + 20 ° C. (more preferably Tv−50 ° C. ≦ Ts ≦ Tv + 10 ° C., more preferably Tv−30 ° C. ≦ Ts ≦ Tv).
The “time point at which vapor deposition is started” refers to the time point when the gaseous SAM forming material starts to be deposited on the surface of the substrate. For example, the SAM-forming material is heated in a state where a SAM-forming material (typically liquid or solid) and a substrate coexist in a predetermined vapor deposition space (in a sealed reaction vessel or the like) to form the SAM. The point in time when the material is volatilized and can be deposited on the substrate surface. In an example described later, a base material and a SAM forming material held at a predetermined temperature of 50 ° C. or higher (for example, 150 ° C.) are placed in a reaction vessel and sealed. Such an operation method is a preferred embodiment for setting the temperature of the base material at the start of vapor deposition (initial base material temperature) to a predetermined temperature.

In the production method of the present invention, a substrate mainly composed of the various materials as described above can be used as it is (in particular, without pretreatment). In addition, it is preferable to use a substrate that has been appropriately pretreated as necessary (for example, depending on the material of the substrate, the surface state, the type of SAM forming material to be used, the quality of the target SAM, etc.). Can do. Such pretreatment includes a treatment for cleaning the surface of the substrate, a treatment for highly flattening the surface of the substrate (preferably at an atomic level), a treatment for forming fine irregularities on the surface of the substrate, and a surface of the substrate. A process for introducing a functional group (typically a functional group suitable for adsorption of the SAM-forming material, such as a hydroxyl group), a process for modifying the surface of the substrate (for example, a process for forming an oxide film on the substrate surface) 1 type or 2 types or more selected from etc. may be included.
The surface of the substrate can be washed by physical treatment such as immersing the substrate in an appropriate liquid and applying ultrasonic vibration, or by treating the substrate with an appropriate chemical (typically acid, alkali, peroxide) 1 type or 2 types selected from chemical processing such as treatment with one or more selected from materials, etc., high energy ray treatment that irradiates the substrate with high energy rays such as ultraviolet rays and electron beams, etc. The above can be adopted as appropriate. An example of a chemical that can be preferably used for the chemical treatment is a piranha solution (a mixture of 98% sulfuric acid and 30% hydrogen peroxide water in a volume ratio of 3: 1). Moreover, as a suitable example of a high energy ray process, the process which irradiates vacuum ultraviolet light (ultraviolet light with a wavelength in the range of 100-300 nm) among ultraviolet rays can be illustrated. Such vacuum ultraviolet light irradiation can be carried out using a conventionally known vacuum ultraviolet light irradiation apparatus equipped with a light source such as an excimer lamp or an H ₂ lamp.

The method of the present invention can be applied to the case where a SAM is formed on any crystal plane of a silicon substrate. For example, by applying the method of the present invention, a SAM can be formed on the (111) plane, the (110) plane, etc. (particularly preferably the (111) plane) of the silicon substrate. Here, usually, a thin oxide film (silica layer) is formed on the surface of the silicon substrate by natural oxidation. Such an oxide film can preferably contribute to the adsorption of the SAM forming material (for example, alkoxysilane). In one preferred embodiment of the method disclosed herein, the oxide film on the surface of the silicon substrate is once completely removed (at least substantially completely). Such removal of the oxide film can be realized, for example, by performing a hydrogen termination process on the surface of the silicon substrate. Such a hydrogen termination treatment can be grasped as a suitable example of a treatment for highly flattening the surface of the substrate. The specific method for the hydrogen termination treatment is not particularly limited, and can be carried out in the same manner as the hydrogen termination method known in the semiconductor manufacturing field and the like. For example, the silicon substrate may be immersed in an aqueous solution of ammonium fluoride (NH ₄ F), hydrogen fluoride (HF), or the like.
Next, oxygen atoms are newly introduced into the surface of the silicon substrate terminated with hydrogen. As a preferable method for introducing such a functional group, a method of irradiating vacuum ultraviolet light in an atmosphere containing oxygen (for example, atmospheric pressure or reduced pressure) can be exemplified. Thereby, a functional group containing oxygen (for example, a hydroxyl group, that is, a silanol group) can be introduced into the surface of the silicon substrate.

  Such hydrogen termination is applied not only to silicon substrates, but also to pretreatment of substrates made of other materials to produce the desired effect (typically, higher quality SAMs by subsequent chemical vapor deposition). Effect). The material of the base material to which such treatment is applied is not particularly limited as long as it is a material capable of hydrogen termination. For example, it may be a base material mainly composed of materials such as silicon, silicon carbide, germanium, graphite and the like. The whole base material may be a base material made of such a material, or even a base material having a layer made of the above material on at least a surface portion (portion where SAM is to be formed) of the base material. Good.

FIG. 8 shows a schematic configuration example of an apparatus that can be preferably used in the SAM manufacturing method disclosed herein. This SAM production apparatus 1 roughly includes a reaction vessel 10, an atmospheric temperature control means 20 for controlling the temperature in the vessel, a humidity control means 30 for controlling the humidity in the vessel, And substrate temperature adjusting means 40 for adjusting the temperature of the arranged substrate.
A gas inlet 12 and a gas outlet 14 are formed on the wall surface (for example, the ceiling portion) of the reaction vessel 10 to communicate the inside and outside of the vessel. The gas inlet 12 is connected to source gas supply means 11 capable of supplying a gas containing a SAM forming material (for example, a mixed gas of a SAM forming material gas and a carrier gas) into the container 10. The ambient temperature control means 20 includes a thermometer 22 arranged inside the container 10 and a heater 24 provided so as to surround the outer periphery of the container 10, and according to the temperature detection result by the thermometer 22, The temperature (atmosphere temperature) in the container 10 can be controlled by adjusting the output. The humidity control means 30 includes a hygrometer 32 disposed inside the container 10, and adjusts the composition (humidity) of the gas supplied from the gas inlet 12 according to the humidity detection result by the hygrometer 32, for example. Thus, the humidity in the container 10 (atmosphere gas humidity) can be controlled. Inside the reaction vessel 10 (for example, the bottom surface), a substrate mounting table 16 for mounting the substrate 50 is provided. The substrate temperature adjusting means 40 includes a thermometer 42 built in the substrate mounting table 16 and a heater 44 configured to be able to adjust the output according to the temperature detection result by the thermometer.

An example of the SAM manufacturing method disclosed herein will be outlined with reference to a process diagram shown in FIG.
First, a base material (for example, a silicon substrate) is cleaned using acetone, ethanol, and ultrapure water in this order (step S102), and further a piranha solution (98% sulfuric acid and 30% hydrogen peroxide solution in a volume of 3: 1). (Mixed in a ratio)) (step S104). Next, the substrate is irradiated with vacuum ultraviolet light (step S106). Thereby, a functional group (for example, a hydroxyl group) is introduced into the substrate surface. On the other hand, the container (for example, reaction container 10 shown in FIG. 8) used for the CVD reaction is dried (step S108). That is, the moisture in the container is removed. In order to remove the moisture, for example, the container may be heated in a dry atmosphere. The substrate after step S106 is introduced into the dried container (step S110). For example, the substrate 50 is set on the substrate mounting table 16 shown in FIG. Then, the substrate temperature is adjusted so that the substrate has a predetermined temperature (a temperature higher than room temperature) (step S112). Further, the humidity in the reaction container is controlled to be a predetermined humidity set in advance (step S114). Further, the atmospheric temperature in the reaction vessel is controlled to be a predetermined temperature set in advance (step S116). The control of the ambient temperature can be performed, for example, by adjusting the output of the heater 24 shown in FIG. And source gas is introduce | transduced in reaction container (step S118). For example, a mixed gas of the SAM forming material gas and the carrier gas is supplied from the gas inlet 12 shown in FIG. In this way, a high quality SAM can be formed on the substrate.

  Note that the type and order of use of the solvent (cleaning liquid) used in step S102 and step S104, and the cleaning conditions are not limited to the above-described embodiment, and may be changed as appropriate according to the material, surface condition, and the like of the substrate. Can do. For example, step S104 may be omitted. Moreover, when hydrogen-termination of a base material is performed, for example, it is appropriate to perform it after step S106 for introducing a hydroxyl group after the end of the cleaning step. Moreover, although the case where steps S110 to S118 are performed in this order has been described above as an example, the order in which these steps are performed may be appropriately changed as long as desired chemical vapor deposition conditions are realized. The steps may be performed in parallel or some steps may be omitted.

According to the SAM manufacturing method disclosed herein, according to the type of SAM forming material to be used, a SAM that exhibits a contact angle (for example, a water droplet contact angle) that approximates the contact angle expected from the SAM forming material is manufactured. Can do. Here, “expected contact angle” means (a) a SAM-forming material capable of forming a SAM on a substrate in the same form as the SAM-forming material used in the production method of the present invention (at least a tail group is common). SAM formed by a general liquid phase method using a compound, preferably a compound having a common tail group and head group (typically the same compound as the SAM forming material used in the production method of the present invention) An angle (for example, a water droplet contact angle) or (b) a contact angle theoretically derived from the chemical structure of the SAM used in the production method of the present invention (such as the structure of the tail group of the SAM-forming material used). According to one preferred embodiment of the method disclosed herein, a SAM having a difference from an expected contact angle of ± 10 ° or less can be produced. According to a more preferred embodiment, a SAM having a difference from an expected contact angle of ± 5 ° or less can be produced.
The water droplet contact angle can be measured by various conventionally known means. For example, the static contact angle of distilled water can be measured using a contact angle measuring device (model “CA-X150”) manufactured by Kyowa Interface Science Co., Ltd.

The suitable ranges of the atmospheric temperature and the atmospheric gas humidity during chemical vapor deposition may vary depending on the type of SAM forming material used. For example, when trialkoxysilane having an unsubstituted alkyl group having 10 to 30 carbon atoms as a tail group is used as the SAM forming material, the ambient temperature is about 80 to 170 ° C. (more preferably about 90 to 160 ° C.). Especially good results can be obtained by setting the humidity of the atmospheric gas to about 10 to 20% (more preferably about 15 to 20%). Examples of the SAM forming material to which such deposition conditions are particularly preferably applied include compounds represented by the general formula: CH ₃ (CH ₂ ) _n Si (OR ₃ ) ₃ ; Here, n in the above general formula is an integer selected from 9 to 29, and R is a methyl group or an ethyl group.

Further, for example, trialkoxysilane having a group in which 70% or more of hydrogen atoms of an alkyl group having 10 to 30 carbon atoms are replaced with a halogen atom (typically a fluorine atom) as a tail group is used as the SAM forming material. In some cases, the ambient temperature is preferably about 100 to 200 ° C. (more preferably about 130 to 170 ° C.) and the humidity of the atmosphere gas is about 5 to 13% (more preferably about 7 to 12%). Results. Examples of the SAM forming material to which such deposition conditions are particularly preferably applied include compounds represented by the general formula: CF ₃ (CF ₂ ) _p (CH ₂ ) _q Si (OR ₃ ) ₃ ; Here, p and q in the above general formula are such that p + q is an integer of 9 to 29, and the fluorine substitution rate represented by the following formula: (2p + 3) / (2p + 2q + 3) × 100 is 70% or more. Is a natural number chosen to be R is a methyl group or an ethyl group.

For example, when a trialkoxysilane having an aryl group or alkylaryl group substituted with an amino group (typically having an amino group at the para-position of the benzene ring) as a tail group is used as the SAM-forming material. Particularly good results can be obtained by setting the atmospheric temperature to about 80 to 170 ° C. (more preferably about 80 to 130 ° C.) and the humidity of the atmospheric gas to about 10 to 20% (more preferably about 10 to 15%). can get. Examples of the SAM forming material to which such deposition conditions are particularly preferably applied include compounds represented by the general formula: NH ₂ C ₆ H ₄ (CH ₂ ) _m Si (OR ₃ ) ₃ . Here, m in the above general formula is an integer of 0 to 3, and R is a methyl group or an ethyl group.

For example, a trialkoxysilane having an aryl group substituted with a halogenated alkyl group or an alkylaryl group (typically having a halogenated alkyl group at the para-position of the benzene ring) as a tail group is used as the SAM forming material. When used, the atmospheric temperature is preferably about 80 to 170 ° C. (more preferably about 80 to 130 ° C.), and the humidity of the atmospheric gas is about 10 to 20% (more preferably about 10 to 15%). Good results are obtained. Examples of the SAM forming material to which such deposition conditions are particularly preferably applied include compounds represented by the general formula: CX ₃ C ₆ H ₄ (CH ₂ ) _m Si (OR ₃ ) ₃ . Here, X in the above general formula is any selected from a hydrogen atom and a halogen atom (for example, a chlorine atom and / or a fluorine atom). m is an integer of 0 to 3, and R is a methyl group or an ethyl group.

The membrane material disclosed herein comprises a substrate and a SAM formed on the substrate. The SAM constituting the film material may be a high-density film having a coverage of about 85% or more (typically about 85 to 98%). In one preferred embodiment, the coverage of the SAM is about 90% or more (typically about 90 to 95%).
The SAM constituting the film material may be a film produced by chemical vapor deposition of a SAM forming material on a base material. The chemical vapor deposition is preferably performed, for example, under the conditions of (1) atmospheric gas humidity (relative humidity at 25 ° C.) of about 30% or less (typically about 5 to 30%). Further, (2) it is preferable to carry out under the condition of the ambient temperature of about 60 ° C. or higher (for example, about 100 to 200 ° C.) Furthermore, (3) it is preferable that the surface temperature of the base material at the time of starting vapor deposition is higher than room temperature (preferably about 80 ° C. or higher). A film material including a SAM obtained by performing chemical vapor deposition so as to satisfy all of the conditions (1) to (3) is particularly preferable.

Since the SAM constituting the film material is obtained by chemical vapor deposition, the utilization efficiency of the SAM forming material at the time of forming the SAM is good. This is advantageous, for example, from the viewpoint of reducing the manufacturing cost of the film material. Moreover, it has the advantage that there is little environmental load at the time of manufacture of this film | membrane material.
Since such a film material has a high coverage (that is, high density) SAM, the film characteristics (for example, characteristics expected from the molecular structure of the SAM forming material) are more appropriately exhibited. obtain. For example, an appropriate water-repellent film (water-repellent film), a hydrophilic film (hydrophilic film), or a lubricating film (lubricant film) depending on the type of SAM forming material (particularly the type of tail group) It can be. Other aspects of the film material of the present invention having a SAM exhibiting such characteristics include a water-repellent film material (for example, a film material exhibiting super-water repellency with a contact angle of 150 ° C. or higher), a hydrophilic film material, and lubricity. It can be grasped as a film material or the like.
Moreover, since the SAM coats the base material at a high density, the base material is excellent in protective performance (performance as a protective film). For example, the SAM imparts good antifouling properties, water resistance (a concept including water absorption resistance, moisture absorption resistance, etc.), chemical resistance (a concept including corrosion resistance) and the like to the substrate. can do.

  Such a high-density SAM is suitable for forming a high-definition pattern by the SAM itself or by using the SAM for positioning or the like. Therefore, the film material can be suitably used as a film material (resist material) for producing various patterns. For the formation of such a pattern, for example, various conventionally known patterning techniques such as lithography (photolithography) can be appropriately used. In a preferred embodiment, a film material having SAM is prepared on the surface of the substrate, and light is irradiated to a predetermined portion of the SAM. As light to irradiate, for example, ultraviolet light, vacuum ultraviolet light (typically vacuum ultraviolet light having a wavelength of 200 nm or less) and the like can be preferably used. By removing and / or altering the SAM of the light-irradiated part (concept including decomposition of the tail group, removal of the functional group or conversion to another functional group, introduction of a new functional group, etc.) A film material having a SAM formed in a predetermined pattern can be obtained. The high density of the SAM is advantageous from the viewpoint of realizing higher resolution lithography (forming a higher definition pattern).

  A film material having a SAM formed in a predetermined pattern is selected for use in selectively applying another material on the SAM pattern, in a portion excluding the SAM pattern (in a form reversed to the SAM pattern). In particular, it can be preferably used for various applications such as an application for adding other materials. For example, a metal plating layer can be selectively formed on the SAM pattern by performing metal plating on a film material in which a SAM having a high affinity for metal is formed in a predetermined pattern. Further, for example, by exposing a film material in which a SAM showing water repellency is formed in a predetermined pattern to solder vapor, a solder layer is formed by selectively attaching solder to a portion excluding the SAM pattern. Can do.

  In one preferred example of the film material disclosed herein, a metal plating layer is selectively formed on the SAM pattern. As the film material having such a configuration, for example, a film material in which a SAM (for example, a SAM having a thiol (-SH) group) having a high affinity for a metal is formed in a predetermined pattern is used. It can be produced by plating any metal by applying an electroless plating method. The electroless plating method may include performing sensitization on a film material having a SAM pattern that exhibits high affinity for the metal. For example, a metal (for example, divalent tin ion) that can act as a reducing agent is preferentially (preferably selectively) deposited on the SAM pattern by, for example, immersing the film material in a stannous chloride solution. . The electroless plating method may also include performing an activation process on a film material having a SAM pattern that exhibits a high affinity for the metal. For example, by immersing the membrane material in a palladium chloride solution, a metal (for example, palladium) that can act as a catalyst in the electroless plating method is preferentially (preferably selectively) deposited on the SAM pattern. Only the activation process may be performed, or the activation process may be performed following the sensitization process. In addition, with respect to specific materials and operation methods used in the electroless plating method, plating conditions, and the like, the same materials, methods and conditions as those of conventionally known electroless plating methods can be adopted as appropriate. Is omitted.

Hereinafter, the present invention will be described in more detail with reference to examples.
<Method for producing SAM>
In Examples 1 to 5 below, a SAM was formed on the (111) plane of an n-type low resistance (0.01 to 0.02 Ωcm) silicon substrate according to the following procedures (1) to (6).

(1) The silicon substrate was subjected to ultrasonic cleaning with acetone for 10 minutes, then subjected to ultrasonic cleaning with ethanol for 10 minutes, and further with ultrapure water for 10 minutes (step S102 shown in FIG. 9).
(2) The substrate was washed with a piranha solution (a mixture of 98% sulfuric acid and 30% hydrogen peroxide solution in a volume ratio of 3: 1) to remove contamination adhering to the substrate surface (same as above). Step S104).
(3) In order to highly planarize the surface of the substrate, the silicon substrate was treated with an aqueous NH ₄ F solution having a concentration of 40% by mass to terminate the surface of the substrate with hydrogen (not shown in FIG. 9). In general, the hydrogen termination process may be performed after step S104 and before step S106.)
(4) The surface of the hydrogen-terminated substrate is generated from an excimer lamp (USHIO ELECTRIC CO., LTD., Model “UER20-172V”, wavelength λ = 172 nm, irradiation energy density 10 mWcm ⁻² ) at room temperature under atmospheric pressure. Vacuum ultraviolet light (VUV) was applied for 60 minutes (step S106). The distance from the lamp to the substrate was about 10 mm. By such VUV irradiation, functional groups (mainly silanol groups) suitable for forming a SAM using a SAM forming material described later were introduced into the (111) surface of the silicon substrate.
(5) The substrate subjected to the VUV irradiation of (4) above was placed in a Teflon (registered trademark) reaction vessel (volume 65 mL), introduced into an electric furnace, and heated at 150 ° C. for 10 minutes. Thereby, the adsorbed water on the reaction vessel and the substrate surface was removed (step S108).
(6) The silicon substrate and reaction vessel that had undergone the heat treatment of (5) above were transferred to a glove box maintained at a predetermined humidity (atmospheric gas humidity). Within the glove box, the silicon substrate was enclosed in the reaction vessel together with the SAM forming material placed in a glass cup. That is, the substrate and the SAM forming material were accommodated in a reaction container, and the container was sealed (sealed). The sealed reaction vessel was held in an electric furnace having a predetermined atmospheric temperature for 3 hours. Thereby, the SAM forming material was chemically vapor-deposited on the surface of the silicon substrate, and SAM was formed on the surface of the substrate.

<Measurement method of contact angle>
The contact angle of SAM shown in the following examples is a value obtained by measuring the static contact angle of distilled water in a 25 ° C. atmosphere by a droplet method (droplet diameter of about 2 mm). For this contact angle measurement, a contact angle measuring device (model “CA-X150”) manufactured by Kyowa Interface Science Co., Ltd. was used.

<Measurement method of coverage>
The SAM coverage shown in the following examples was calculated using the Cassie-Baxter relational expression represented by the above-described formula (i). For the measurement of the water contact angle, an automatic contact angle / surface tension meter, model “DSA10-Mk2” manufactured by KRUS was used.

<Example 1: Production of SAM using ODS (examination of substrate temperature)>
In this example, n-octadecyltrimethoxysilane represented by CH ₃ (CH ₂ ) ₁₇ Si (OCH ₃ ) ₃ (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter abbreviated as “ODS”) is used as the SAM forming material. It was used.
[Sample 1] In the procedure (6), the substrate and the SAM forming material were sealed in the reaction vessel while the substrate and the reaction vessel heated to 150 ° C. in the procedure (5) were kept at the same temperature. Then, the substrate and the reaction vessel were introduced into an electric furnace having an atmospheric temperature of 150 ° C. while maintaining the same temperature (here, 150 ° C.). In this way, a silicon substrate (sample 1) on which the SAM derived from ODS was formed was obtained.

  [Sample 2] In the procedure (6), the substrate and the SAM forming material were sealed in the reaction vessel while maintaining the substrate and the reaction vessel heated to 150 ° C. in the procedure (5) at 80 ° C. Then, while maintaining the substrate and the reaction vessel at the same temperature (here, 80 ° C.), the reaction vessel was introduced into an electric furnace at 150 ° C. In this way, a silicon substrate (sample 2) on which a SAM derived from ODS was formed was obtained.

  [Sample 3] In the procedure (6), the temperature of the substrate and the reaction vessel was not particularly controlled. Therefore, the temperature of the substrate and the reaction vessel during the sealing operation was almost the same as the temperature of the glove box (room temperature). Except for this point, a silicon substrate (sample 3) on which a SAM derived from ODS was formed was obtained in the same manner as in sample 1.

  [Sample 4] Similar to sample 3, in the procedure (6), the temperature of the substrate and the reaction vessel was not particularly controlled. However, the output of the electric furnace was adjusted so that the substrate introduced into the electric furnace reached the ambient temperature (here, 150 ° C.) more quickly than the sample 3. Except for this point, a silicon substrate (sample 4) on which a SAM derived from ODS was formed was obtained in the same manner as in sample 3.

FIG. 1 shows the temperature profile of the silicon substrate in the process of chemical vapor deposition of the SAM forming material (here, ODS) in the production of these samples 1 to 4.
In any of the samples 1 to 4, when performing the sealing operation, the inside of the glove box was an atmosphere in which a small amount of air was mixed in dry nitrogen (N ₂ ). The humidity of the atmospheric gas (that is, a mixed gas of N ₂ and a small amount of air) was controlled to be 10 to 15% in terms of relative humidity at 25 ° C. In this example, the humidity of the atmospheric gas was controlled in the above range by adjusting the amount of air mixed into the dry nitrogen.

  The static contact angle of each SAM thus obtained was measured by the above method. The results are shown in Table 1. The contact angle of SAM formed from ODS is theoretically said to be about 110 °. In fact, the contact angle (that is, the expected contact angle) of a SAM formed almost ideally by a general liquid phase method using ODS is usually about 110 °.

As can be seen from the comparison of Samples 1 to 3, by bringing the substrate temperature at the start of deposition closer to the ambient temperature than room temperature, a contact angle close to the expected contact angle (specifically, the expected contact angle A SAM showing a difference (SAM with a difference of ± 1 ° or less) was obtained. As can be seen from the comparison between sample 3 and sample 4, the effect of reducing the difference from the expected contact angle was also seen by making the temperature gradient from the beginning of vapor deposition abrupt.
Moreover, the value of the coverage measured (calculated) for each sample by the above method increased in the order of Sample 3, Sample 4, Sample 2, and Sample 1 in the same manner as the contact angle values shown in Table 1. Among them, the SAMs of Sample 1 and Sample 2 showed a high coverage ratio exceeding 90%, and in particular, the excellent coverage ratio of 96% was realized in Sample 1.

<Example 2: Production of SAM using ODS (examination of humidity and temperature)>
In the above procedure (6), the humidity in the glove box (atmosphere gas humidity) was controlled to be the value shown in Table 2 (represented by the relative humidity at 25 ° C., the same applies hereinafter). A substrate and ODS were sealed and sealed in a reaction vessel under each atmospheric gas humidity, and these were held in an electric furnace at each atmospheric temperature shown in Table 2 for 3 hours to form a SAM. During the procedure (6), the temperature of the substrate and the reaction vessel was maintained at 150 ° C. as in the case of the sample 1.

  The static contact angle of each SAM thus obtained was measured by the above method. The results are shown in Table 2 and FIG. Here, the symbol “A” in the table indicates that the difference between the contact angle of the ODS-SAM obtained in this example and the expected contact angle (110 ° for ODS) was less than ± 5 °. Represents that. The symbol “B” indicates that the difference from the contact angle is 5 ° or more and less than 10 °, the symbol “C” indicates that the difference is 10 ° or more and less than 20 °, and the symbol “X” indicates that the difference is 10 ° or less. It represents that the difference was 20 ° or more.

  Similarly, SAMs were produced under the conditions shown in Table 3, and the coverage of these SAMs was measured (calculated) by the above method. The results are shown in Table 3. In the table, the unit of the value indicating the coverage is%.

<Example 3: Production of SAM using HFDTS (examination of humidity and temperature)>
In this example, heptadecafluoro-1,1,2, represented by CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ is used as a SAM forming material instead of the ODS used in Example 2. 2-tetrahydrodecyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter abbreviated as “HFDTS”) was used. Other points were the same as in Example 2, and SAMs were produced under each atmospheric gas humidity and each atmospheric temperature shown in Table 4. That is, in the procedure (6), the substrate and the SAM forming material are sealed in the reaction vessel while the substrate and the reaction vessel heated to 150 ° C. in the procedure (5) are continuously maintained at the same temperature (ie, 150 ° C.). did. The results of measuring the contact angles of these SAMs by the above method are shown in Table 4 and FIG. Here, the meanings of the symbols “A”, “B”, “C” and “X” in the table are the same as those in Table 2. In addition, the contact angle (that is, the expected contact angle) of a SAM formed almost ideally by a general liquid phase method using HFDTS is usually about 123 °.

  Similarly, SAMs were produced under the conditions shown in Table 5, and the coverage of these SAMs was measured (calculated) by the above method. The results are shown in Table 5. In the table, the unit of the value indicating the coverage is%.

<Example 4: Production of SAM using AHPS (examination of humidity and temperature)>
In this example, p-aminophenyltrimethoxysilane (hereinafter referred to as “AHPS”) represented by p-NH ₂ C ₆ H ₄ Si (OCH ₃ ) ₃ is used as a SAM-forming material instead of the ODS used in Example 2. Abbreviated.) Was used. Other points were the same as in Example 2, and SAMs were produced under each atmospheric gas humidity and each atmospheric temperature shown in Table 6. The results of measuring the contact angles of these SAMs by the above method are shown in Table 6 and FIG. Here, the meanings of the symbols “A”, “B”, “C” and “X” in the table are the same as those in Table 2. In addition, the contact angle (that is, the expected contact angle) of a SAM formed almost ideally by a general liquid phase method using AHPS is usually about 60 °.

<Example 5: Production of SAM using CMPS (examination of humidity and temperature)>
In this example, p-chloromethylphenyltrimethoxysilane (hereinafter referred to as “CMPS”) represented by p-CH ₂ ClC ₆ H ₄ Si (OCH ₃ ) ₃ was used as a SAM forming material instead of the ODS used in Example 2. Abbreviated as). Other points were the same as in Example 2, and SAMs were produced under each atmospheric gas humidity and each atmospheric temperature shown in Table 7. The results of measuring the contact angles of these SAMs by the above method are shown in Table 7 and FIG. Here, the meanings of the symbols “A”, “B”, “C” and “X” in the table are the same as those in Table 2. Further, the contact angle (that is, the expected contact angle) of a SAM formed almost ideally by a general liquid phase method using CMPS is usually about 60 °.

<Example 6: Fabrication of pattern by photolithography>
Of the samples prepared in Example 2, those having a SAM prepared on a silicon substrate under conditions of an atmospheric temperature of 200 ° C. and an atmospheric gas humidity of 25% (contact angle of about 104 °, coverage of about 88%; A film material is referred to as “sample P1”), and has a SAM manufactured under the conditions of an atmospheric temperature of 100 ° C. and an atmospheric gas humidity of 15% (contact angle of about 108 °, coverage of about 93%; "Sample P2"), and having an SAM manufactured under conditions of an atmospheric temperature of 150 ° C and an atmospheric gas humidity of 20% (contact angle of about 110 °, coverage of about 95%; hereinafter, this film material is referred to as "sample P3 ”) was patterned by irradiation with vacuum ultraviolet light (VUV). As the photomask, a photomask having a shape in which rectangular holes having a width of 5 μm and a length of 25 μm were arranged in the width direction and the length direction was used. The interval between adjacent holes is 5 μm in both the width direction and the length direction. In this manner, a film material in which a high-density SAM produced by ODS chemical vapor deposition was formed in a predetermined pattern (SAM pattern) on a silicon substrate was obtained.
FIG. 6 shows shape images of SAM patterns formed on these film materials by AFM (Atomic Force Microscopy). 6A is a SAM pattern obtained from the sample P1, FIG. 6B is a SAM pattern obtained from the sample P2 under the same conditions, and FIG. 6C is a SAM pattern obtained from the sample P3 under the same conditions. It is a shape image. As can be seen from these images, there was a tendency that the precision of the pattern (for example, resolution, clarity of the outer edge of the pattern, shape accuracy) was higher in the order of the samples P1, P2, and P3. This result shows that when these SAMs are used as a resist film, the performance for realizing high-resolution lithography is improved in the order of P1, P2, and P3.

Note that the photolithography of the SAM obtained by the method disclosed herein using vacuum ultraviolet light can be performed, for example, at an atmospheric pressure of approximately 10 to 10 ⁵ Pa (more preferably approximately 10 to 10 ³ Pa). . The irradiation time of vacuum ultraviolet light can be, for example, in the range of about 10 to 60 minutes, and is usually preferably in the range of about 30 to 60 minutes. In this example, by irradiating vacuum ultraviolet light generated from an excimer lamp (USHIO INC., Model “UER20-172V”, wavelength λ = 172 nm, irradiation energy density 10 mWcm ⁻² ) at an atmospheric pressure of 10 Pa for 20 minutes. SAM patterning was performed.

<Example 7: Fabrication of pattern by AFM probe>
For the film material samples P1, P2, and P3, a linear pattern was prepared using an AFM probe. A trade name “SSS-NCHR-10” manufactured by NANOWORLD was used as the AFM probe. The distance between the probe tip and the SAM surface was controlled to be about 0.5 to 2 nm. Thus, a film material in which a high-density SAM produced by chemical vapor deposition of ODS was formed in a predetermined pattern (SAM pattern) on the silicon substrate was obtained.
FIG. 7 shows shape images of SAM patterns formed on these film materials by AFM (Atomic Force Microscopy). 7A shows a SAM pattern (line width of 45 to 50 nm) obtained from the sample P1, FIG. 7B shows a SAM pattern (line width of 35 to 40 nm) obtained from the sample P2 under the same conditions, and FIG. C) is a shape image of a SAM pattern (line width 20 to 25 nm) obtained from the sample P3 under the same conditions. As can be seen from these images, there was a tendency that the pattern precision (for example, resolution, clarity of the outer edge of the pattern) was higher in the order of samples P1, P2, and P3. This result shows that when these SAMs are used as a resist film, the performance for realizing high-resolution lithography is improved in the order of P1, P2, and P3.

Note that the photolithography by SAM AFM obtained by the method disclosed herein is preferably performed, for example, at a temperature of approximately 20 to 30 ° C. (more preferably approximately 25 to 28 ° C.). The humidity at the time of performing the lithography is preferably in the range of about 35 to 60%, more preferably in the range of about 40 to 55% as the relative humidity at 25 ° C. The applied voltage at the time of lithography is preferably in the range of about 7 to 10V, and more preferably in the range of about 7 to 8.5V. In this example, SAM patterning was performed under conditions of a humidity of 40 to 45%, a temperature of 25 ° C., and an applied voltage of 8V.
For the samples P1, P2, and P3, the product name “SSR-NCHR-10” manufactured by NANOSENSORS is used as the AFM probe, and the distance between the probe tip and the SAM surface is controlled to be about 5 to 10 nm. SAM patterning was performed under the conditions of humidity 35-40%, temperature 23 ° C., applied voltage 7V, and the SAM pattern was prepared by the same operation as above. It was confirmed that there was a tendency for the precision of the to become higher.

<Example 8: Production of film material having SAM on silicon substrate>
In this example, 3-mercaptopropyltrimethoxysilane (hereinafter abbreviated as “MPS”) represented by HSCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ was used as the SAM forming material. Hereinafter, the manufacturing method of the film material according to the present embodiment will be described with reference to the drawings.
As shown in FIG. 10A, a silicon substrate 200 that has been subjected to the pretreatments of the above-described procedures (1) to (3) is prepared in the same manner as in the first to fifth embodiments, and the surface 202 ( The surface on which the SAM is to be formed (here, (111) plane) was irradiated with VUV. This VUV irradiation was performed for 30 minutes using the same excimer lamp used in the above procedure (4). The distance from the lamp to the substrate was about 10 mm. By such VUV irradiation, as shown in FIG. 10B, functional groups (mainly silanol groups) suitable for forming SAMs were introduced into the surface (surface) 202 to be processed of the silicon substrate 200.

  The silicon substrate was placed in a Teflon (registered trademark) reaction vessel (volume 65 mL), introduced into an electric furnace, and heated at 150 ° C. for 10 minutes. This removed the adsorbed water on the reaction vessel and the substrate surface. The silicon substrate and the reaction vessel were transferred to a glove box adjusted to an atmospheric gas humidity of 15% (relative humidity at 25 ° C.). In the glove box, as shown in FIG. 11, the silicon substrate 200 was enclosed in the reaction vessel 210 together with the SAM forming material (MPS in this case) 214 placed in the glass bottle 212. That is, the substrate 200 and the SAM forming material 214 were accommodated in the reaction vessel 210 and the vessel was sealed (sealed). The sealing operation was performed while maintaining the temperature of the silicon substrate 200 and the reaction vessel 210 at the above temperature (that is, 150 ° C.). The sealed reaction vessel 210 was held in an electric furnace 220 adjusted to an atmospheric temperature of 150 ° C. for 3 hours, thereby chemically depositing the SAM forming material 214 on the surface 202 of the silicon substrate 200.

  In this way, as shown in FIG. 10 (3), the film material 2 in which the SAM (MPS-SAM) 204 derived from MPS was formed on the surface 202 of the silicon substrate 200 was obtained. When the static contact angle of the MPS-SAM was measured by the above method, it was about 67 °. Moreover, when the coverage of this MPS-SAM was measured by the said method, it was about 88%. Note that the contact angle (that is, the expected contact angle) of a SAM formed almost ideally by a general liquid phase method using MPS is usually about 72 °.

Next, as shown in FIG. 12A, a photomask having a shape in which rectangular holes having a width of 50 μm and a length of 200 μm are arranged in the width direction and the length direction on the SAM formation surface of the film material 2. VUV was irradiated through 222. More specifically, using the same excimer lamp as that used for patterning in Example 6, VUV of wavelength λ = 172 nm was irradiated for 10 minutes at an atmospheric pressure of 10 Pa. As a result, as shown in FIG. 12 (2), the MPS-SAM 204 was decomposed and the surface 202 was exposed in the portion irradiated with VUV. In this way, a film material in which the MPS-SAM 204 is formed in a predetermined pattern on the silicon substrate 200 (that is, a film material in which the MPS-SAM micropattern is formed on the silicon substrate, in other words, MPS-SAM / SiO ₂ ) 3) was obtained.

  Furthermore, the membrane material 3 was subjected to activation for forming a copper plating layer described later. Specifically, palladium (Pd) was adhered to the membrane material 3 by immersing the membrane material 3 in an acidic solution (pH 5) of a palladium chloride solution at 25 ° C. for 1 minute. Here, MPS has a thiol group (—SH) at the end of the tail group. Utilizing the fact that this thiol group shows high affinity with metals (for example, gold, silver, copper, iron, platinum, palladium and alloys containing them), the attachment of palladium is given priority on MPS-SAM. (Typically, selectively on MPS-SAM). Subsequently, the above-mentioned film material to which palladium was attached was applied to a commercially available plating solution for electroless copper plating (here, Nippon Kojun Chemical Co., Ltd., grade name “C-200LT” was used) at 25 ° C. Soaked for 10 seconds. Thus, as shown in FIG. 12 (3), a film material 4 was obtained in which the copper plating layer (copper plating film) 208 was selectively formed on the patterned MPS-SAM 204.

When the surface of the film material 3 obtained by the above method was observed with a scanning electron microscope (SEM), it was confirmed that the MPS-SAM 204 having a form well corresponding to the form of the used photomask 222 was formed. . The outer edge (edge) of the SAM 204 had good clarity.
Further, when the surface of the film material 4 was observed with an SEM, it was confirmed that the copper plating layer 208 having a form corresponding to the form of the pattern 204 was formed on the patterned MPS-SAM 204. The outer edge of the copper plating layer 208 had good clarity.

<Example 9: Production of film material having SAM on epoxy substrate>
A commercially available epoxy substrate for printed wiring board was prepared (Cylinder Plastic Industry Co., Ltd. product, trade name “EPG100” was used), and this was ultrasonically cleaned with acetone for 10 minutes, and then with ethanol for 10 minutes. Ultrasonic cleaning for 10 minutes was performed with ultrapure water (step S132 shown in FIG. 13).
Next, the surface of the epoxy substrate was irradiated with VUV for 30 minutes by the same excimer lamp used in the procedure (4) at room temperature under atmospheric pressure (step S136). The distance from the lamp to the substrate was about 3 to 5 mm.

The epoxy substrate that had undergone such VUV irradiation was placed in a Teflon (registered trademark) reaction vessel (volume 65 mL), introduced into an electric furnace, and heated at 150 ° C. for 10 minutes to remove adsorbed water. The epoxy substrate and the reaction container were transferred to a glove box adjusted to an atmospheric gas humidity of 15% (relative humidity at 25 ° C.). Within the glove box, the epoxy substrate and MPS as the SAM forming material were sealed in a reaction vessel. This enclosing operation was performed while maintaining the temperature of the epoxy substrate and the reaction vessel at the above temperature (ie, 150 ° C.). By holding the reaction vessel in an electric furnace adjusted to an atmospheric temperature of 150 ° C. for 3 hours, MPS was chemically vapor-deposited on the surface of the epoxy substrate to form SAM on the surface (step shown in FIG. 13). S140).
In this way, a film material in which SAM derived from MPS (MPS-SAM) was formed on the surface of the epoxy substrate was obtained. The MPS-SAM had a static contact angle of about 68 ° and a coverage of about 89%.

  Next, VUV is irradiated through a photomask having a shape in which rectangular holes having a width of 50 μm and a length of 200 μm are arranged in the width direction and the length direction on the SAM formation surface of the film material obtained above. did. More specifically, using the same excimer lamp as that used for patterning in Example 6, VUV of wavelength λ = 172 nm was irradiated for 10 minutes at an atmospheric pressure of 10 Pa. Thereby, MPS-SAM of the part irradiated with VUV was decomposed | disassembled and the board | substrate surface was exposed. In this way, a film material in which MPS-SAM was formed in a predetermined pattern on an epoxy substrate (that is, a film material in which an MPS-SAM micropattern was formed on an epoxy substrate) was obtained (shown in FIG. 13). Step S142).

  The same activation treatment (activation) as in Example 8 was performed on the film material with the SAM pattern obtained above. Subsequently, the film material to which the palladium was attached was immersed in the same electroless copper plating solution as used in Example 8 at 25 ° C. for 10 seconds. In this way, a film material in which a copper plating layer (that is, a copper pattern) was selectively formed on the MPS-SAM pattern was obtained (step S144 shown in FIG. 13).

  The surface of the film material thus obtained was observed by SEM. A SEM image of a part of the surface is shown in FIG. Further, FIG. 15 shows an image obtained by observing the surface of the material with a 40 × optical microscope. 14 and FIG. 15 are thin ridge-shaped portions, and the other several dark portions separated from each other indicate non-plated portions. As shown in these drawings, in the film material obtained in this example, a copper plating layer having a form corresponding to the form of the photomask used was formed on the surface of the epoxy substrate. The outer edge of the copper plating layer (copper pattern) had good clarity. This means that the pattern shape of the MPS-SAM formed prior to the formation of the copper plating layer also corresponds well to the form of the photomask used and that the outer edge of the pattern is clear, in other words, the step This confirms that the MPS-SAM formed by S140 has excellent characteristics as a resist material.

  Although the scope of the present invention is not particularly limited, the reason why a good quality SAM can be obtained by employing the production method of the present invention is presumed as follows. That is, in the SAM production by the vapor phase method, when the SAM forming material is chemically vapor-deposited on the substrate, the SAM forming material (raw material molecules) basically reaches a random position on the surface of the substrate. The raw material molecule slides on the surface of the substrate, finds a position that is energetically advantageous compared to other parts, and stably adsorbs (typically, chemical bonding) there. Therefore, in order to form a well-organized (dense) SAM, source molecules that have reached the substrate surface can easily move around the substrate surface to find an energetically advantageous position, And the position of the raw material molecule is not determined until the raw material molecule finds a position that is sufficiently advantageous in terms of energy (until the raw material molecule is chemically bonded to the base material and / or the previously adsorbed raw material molecule Together). In the manufacturing method disclosed herein, the surface temperature of the base material at the start of vapor deposition is set higher than room temperature (preferably 50 ° C. or higher) and the ambient temperature is set to a predetermined value or higher (at least 60 ° C.). This is considered to contribute mainly to the former factor. Further, it is considered that controlling the humidity of the atmospheric gas (for example, using a gas having a humidity of 5 to 30% at 25 ° C.) can mainly contribute to the latter factor. And it is guessed that high quality SAM was formed as mentioned above by performing chemical vapor deposition so that these conditions may be satisfied.

  In addition, as a base material (base material to be processed) to be formed of SAM, in addition to a substrate having silicon or epoxy resin as a main constituent material as in the above example, for example, paper, metal, or other materials are used. A substrate may be employed.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
In addition, the technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

Claims (5)

A method for producing a self-assembled monolayer on a substrate by chemical vapor deposition of a self-assembled monolayer-forming material on the substrate from a gas phase, comprising:
Drying the reaction vessel used for the chemical vapor deposition;
Controlling the humidity in the dried reaction vessel so that the relative humidity at 25 ° C. of the atmospheric gas in the reaction vessel is 5 to 30%; and
Introducing a gas containing a self-assembled monolayer forming material into the reaction vessel, and chemically depositing the introduced self-assembled monolayer forming material from the gas phase on the substrate;
Including
Here, the chemical vapor deposition is performed under the following conditions:
Controlling the relative humidity of the atmospheric gas to 5-30%;
Controlling the ambient temperature in the reaction vessel to 100-200 ° C .; and
The surface temperature of the substrate is 50 ° C. or higher at the time of starting the deposition;
A method for producing a self-assembled monolayer that satisfies all of the above.   The method according to claim 1, wherein an alkoxysilane having at least one alkoxy group is used as the film forming material. As the substrate:
Hydrogen terminating the surface of the substrate; and
Introducing a functional group containing oxygen as a constituent atom into the surface of the hydrogen-terminated substrate;
The method of Claim 1 or 2 using the base material by which the pretreatment containing was given.   The method according to claim 3, wherein the introduction of the functional group containing oxygen is performed by irradiating the hydrogen-terminated substrate surface with vacuum ultraviolet light in an atmosphere containing oxygen molecules.   The method according to claim 1, wherein the base material is a silicon substrate.