JP6757693B2 - Manufacturing method of sample loading plate - Google Patents

Description

The present invention relates to a method for manufacturing a sample loading plate.

Matrix-assisted Laser Desorption Ionization (MALDI method) is known as one of the ionization methods in mass spectrometry. In the MALDI method, a substance (matrix) that easily absorbs laser light and is easily ionized in order to analyze an analysis target that is difficult to absorb laser light or a protein that is easily damaged by laser light, that is, A dispersed sample is used as a sample, and the sample (matrix and analysis target) is ionized by irradiating the sample with a laser beam.

In a mass spectrometer using the MALDI method, a sample is generally placed on a metal sample loading plate called a sample plate (or target plate), and the sample placed on this plate is irradiated with a laser beam. .. At this time, a voltage is applied to the metal sample loading plate as necessary in order to accelerate the ions generated by the irradiation of the laser beam.

Patent Document 1 describes a prior art sample loading plate. FIG. 3 is a cross-sectional view of a prior art sample loading plate.

As shown in FIG. 3, the sample loading plate 100 includes a substrate 110 and a laminated film 120 formed so as to cover the surface of the substrate 110. The laminated film 120 is composed of a conductive interference layer 121 and a hydrophobic film 122. It is described that when the hydrophobic film 122 is formed in an island shape on the conductive interference layer 121 of the sample loading plate 100, the hydrophobic surface formed by the hydrophobic film 122 and the hydrophilic surface on which the conductive interference layer 121 is exposed have more appropriate wettability. ing. When the sample loaded on the sample loading plate 100 has strong hydrophobicity on the sample loading plate 100 (the conductive interference layer 121 is almost not exposed), the contact surface between the sample and the sample loading plate 100 is small, and the sample becomes small. It will be biased there. Further, if the hydrophilicity is strong (the exposure of the conductive interference layer 121 is large), the sample becomes thin and spreads, and the sample becomes thin, which makes it difficult to perform an appropriate analysis. Therefore, it is necessary to have appropriate wettability on the sample loading plate 100 according to the type of sample to be loaded. (For convenience, FIG. 3 does not show the hydrophobic film 122 formed on the conductive interference layer 121 in an island shape.)

As a method of forming the island-shaped hydrophobic film 122 on the conductive interference layer 121 described above, a member containing a hydrophobic material in steel wool is irradiated with an electron beam in a high vacuum on the conductive interference layer 121. , A method of instantly depositing only the hydrophobic material contained in steel wool can be mentioned. Hydrophobic materials included in steel wool are compounds of Si (silicon), C (carbon) and F (fluorine). Then, the target hydrophobic film 122 can be obtained by depositing the hydrophobic material evaporated from the steel wool on the conductive interference layer 121. Alternatively, an island-shaped mask made of metal or ceramics is placed on the hydrophobic film 122 formed on the conductive interference layer 121 _, and the hydrophobic film 122 is exposed to O _2, Ar and its mixed plasma in a vacuum. It is described that the hydrophobic film 122 can be removed to obtain the desired hydrophobic film 122.

Japanese Unexamined Patent Publication No. 2016-121968

However, when a member containing a hydrophobic material in steel wool of the prior art is irradiated with an electron beam in a high vacuum, the hydrophobic material contained in the steel wool evaporates instantly, so that the member is formed on the conductive interference layer. It is difficult to control the shape of the hydrophobic film into an island shape for vapor deposition, and there is a problem that the wettability of the sample loaded on the sample loading plate cannot be made appropriate.

An object of the present invention is to provide a method for manufacturing a sample loading plate capable of appropriately wetting and spreading a sample on the sample loading plate.

In the method for manufacturing a sample loading plate for loading a sample on a substrate, a step of forming an island-like hydrophilic film on one surface of the substrate, and one surface of the substrate on which the hydrophilic film is not formed and the surface of the hydrophilic film are used. A method for producing a sample loading plate, which comprises a step of forming a hydrophobic film and a step of removing the hydrophobic film formed on the surface of the hydrophilic film.

The adhesion between the hydrophilic film and the hydrophobic film is smaller than the adhesion between the substrate and the hydrophobic film, which is a method for manufacturing a sample loading plate.

A method for manufacturing a sample loading plate in which an optical multilayer film is formed on one surface of a substrate to form a hydrophilic film and a hydrophobic film.

The outermost surface of one surface of the substrate forming the hydrophilic film and the hydrophobic film is SiO ₂ , the hydrophilic film is MgF ₂ , and the hydrophobic film is a method for producing a sample loading plate which is a fluorine-based compound.

According to the method for manufacturing a sample loading plate of the present invention, it is possible to provide a sample loading plate capable of appropriately wetting and spreading a sample on the sample loading plate.

It is a figure of the sample loading plate which comprises the manufacturing method of the sample loading plate of this invention. It is a figure which shows the manufacturing method of the sample loading plate of this invention. It is a figure of the sample loading plate of the prior art.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The sample loading plate of this example is placed on a mass spectrometer by the MALDI method, and is used for loading a sample on a sample loading spot and analyzing the mass. The mode for carrying out the invention shown below exemplifies a method for manufacturing a sample loading plate for embodying the idea of the present invention and a sample loading plate comprising the manufacturing method, and the present invention is described below. It is not specific to the method and configuration described. In particular, the manufacturing method and the shapes, materials, relative arrangements, etc. of the members described in the embodiments are not limited to the scope of the present invention unless otherwise specified. In addition, the size and shape of the members shown in each drawing, the positional relationship, and the film layer to be formed may be exaggerated for the sake of clarity.

First, the configuration of the sample loading plate according to the method for manufacturing the sample loading plate according to the embodiment of the present invention will be described with reference to FIG.
FIG. 1A is a plan view of the sample loading plate viewed from the surface side on which the sample is loaded.

The substrate 2 of the sample loading plate 1 is an insulating flat plate having an outer shape of about 50 mm × 40 mm, and the sample loading plate 1 uses, for example, a material such as Al ₂ O ₃ (alumina) for the substrate. Can be made. Further, for example, a notch portion is provided like the lower side for positioning. Further, the flatness of the sample loading plate 1 has an accuracy of 30 μm or less. The outer shape, thickness, etc. are not particularly limited as long as they meet the specifications of the mass spectrometer. The sample loading plate may be surface-finished by a wrapping step or a polishing step in order to ensure flatness. Further, although not shown, a serial number, a barcode, or the like given to the plate may be formed.

The sample loading plate 1 has a substrate 2 formed in a plate shape by having a front surface and a back surface, and a laminated film 3 formed so as to cover one surface of the substrate 2, and a part thereof. Is provided with a laminated film 3 in which a plurality of grooves 4 are formed. In the sample loading plate 1, one surface of the substrate 2 is exposed to the outside at a portion where the groove 4 is formed with respect to the laminated film 3. In this example, the width of the groove 4 is several tens of μm to several hundreds of μm.

The sample loading plate 1 is formed with a plurality of island marks 5 each having a C-shape by a plurality of grooves 4, but only two are shown for convenience. The area surrounded by the island mark 5 having a C-shape (the area surrounded by the groove 4 forming the C-shape) functions as a sample loading area (sample loading spot) for loading the sample on the sample loading plate 1. To do.

FIG. 1B is a diagram for explaining the sample loading plate 1, and is an enlarged cross-sectional view taken along the line BA of FIG. 1A. As described above, the sample loading plate 1 of the present embodiment includes a substrate 2 and a laminated film 3 formed so as to cover one surface of the substrate 2, and a groove 4 is partially formed therein. It has a laminated film 3 formed by the above. The laminated film 3 is composed of an optical multilayer film 6, a hydrophilic film 7a, and a hydrophobic film 7b. The optical multilayer film 6 is laminated on the first transparent layer 6b and the first transparent layer 6b laminated on the first metal layer 6a and the first metal layer 6a laminated on one surface of the substrate 2. A hydrophilic film 7a is formed on the optical multilayer film 6 which is composed of a second transparent layer 6d laminated on the second metal layer 6c and the second metal layer 6c and is further formed so as to cover the substrate 2. A hydrophobic film 7b is formed. The hydrophilic film 7a has an island shape having a substantially circular shape (diameter of 10 nm or less), and the hydrophobic film 7b is formed on the optical multilayer film 6 on which the hydrophilic film 7a is not formed. The gap between the islands of the hydrophilic film 7a is several nm. Unless this gap is sufficiently small with respect to the size of the sample mounted on the sample loading plate 1, the wettability of the sample loaded on the sample loading plate 1 cannot be made appropriate.

The first metal layer 6a is composed of Ni (nickel) and its thickness is set to 80 nm. The first transparent layer 6b is made of Al ₂ O ₃ (alumina), and its thickness is set to 80 nm. Further, the second metal layer 6c is composed of Ti (titanium), and its thickness is set to 10 nm. Further, the second transparent layer 6d is composed of SiO ₂ (silica) and its thickness is set to 90 nm. The hydrophilic film 7a is a monomolecular layer composed of MgF ₂ (magnesium fluoride), and the hydrophobic film 7b is composed of a fluorine-based compound, the thickness thereof being 1 to 3 nm.

FIG. 1 (c) is a view in which the sample 200 is loaded on the surface of the enlarged cross-sectional view (FIG. 1 (b)) of Part B AA of FIG. 1 (a). The liquid sample 200 supplied to the island mark 5 (sample loading area) tends to spread radially along the surface of the island mark 5 due to the influence of gravity. Here, in the present embodiment, the groove 4 forms an island mark 5 having a C-shaped shape. Therefore, the sample 200 loaded on the island mark 5 enters the inside of the groove 4 while spreading radially, and reaches the portion that becomes the bottom of the groove 4, that is, the portion where the substrate 2 is exposed. At this time, since the surface of the substrate 2 is hydrophilic, the sample 200 quickly wets and spreads inside the island mark 5 and the groove 4, and spreads inside the island mark 5 and the groove 4.

Further, the sample 200 wet and spread on the island mark 5 wets and spreads on the surfaces of the hydrophilic film 7a and the hydrophobic film 7b formed on the surface of the island mark 5, but the wet spread of the sample 200 stops at some point, and the sample 200 is an island. On the surface of the mark 5, water droplets have a contact angle with respect to the surface of the island mark 5. This is because the hydrophobic film 7b is formed, so that the sample 200 wets and spreads to the point where the force for suppressing the radial spread of the sample 200 and the force for the sample 200 to spread radially are balanced. ..

Here, the substrate 2 is made of a ceramic material having an insulating property. In the present embodiment, the substrate 2 is made of alumina ceramic having a purity of about 96%, the thickness thereof is 800 μm, and the flatness of the front surface and the back surface thereof is 5 μm or less.

As described above, since the hydrophilic film 7a and the hydrophobic film 7b are formed on the optical multilayer film 6 formed so as to cover the substrate 2, the island mark 5 (hydrophilic film) of the sample loading plate 1 is formed. The sample 200 properly wets and spreads on the surface (of 7a and the hydrophobic membrane 7b).

Next, the main steps of FIGS. 2A to 2E will be illustrated and described with respect to the method of manufacturing the sample loading plate 1 shown in FIG. Unless otherwise specified in each process, it is natural to perform operations such as transfer, inspection, cleaning, drying, and annealing, which are necessary and general operations for each process, and their explanations are omitted. To do.

First, the substrate 2 is formed. Specifically, the base material of the substrate 2 previously molded and fired into the shape shown in FIG. 1 was polished on the front surface and the back surface, and the thickness was set to 800 μm and the flatness was set to 5 μm or less. Obtain the substrate 2.

[Optical multilayer film forming step: FIG. 2A]
Next, the optical multilayer film 6 is laminated and formed on one surface of the substrate 2 obtained by the above method. For example, the first metal layer 6a (Ni = nickel), the first transparent layer 6b (Al ₂ O ₃ = alumina), the second metal layer 6c (Ti = titanium), the second The transparent layer 6d (SiO ₂ = silica) is formed in order. The thickness of each layer is 80 nm for the first metal layer 6a (Ni = nickel), 80 nm for the first transparent layer 6b (Al ₂ O ₃ = alumina), and 10 nm for the second metal layer 6c (Ti = titanium). The second transparent layer 6d (SiO ₂ = silica) was set to 90 nm.

[Steps for forming hydrophilic membrane 7a and hydrophobic membrane 7b: FIGS. 2 (b) to 2 (c)]
Next, the hydrophilic film 7a and the hydrophobic film 7b are formed so as to cover the optical multilayer film 6 with respect to the optical multilayer film 6 formed so as to cover one surface of the substrate 2 described above. In this example, MgF ₂ is formed on the hydrophilic film 7a, and a fluorine-based compound is formed on the hydrophobic film 7b. A hydrophilic film 7a (MgF ₂ ) was formed on the optical multilayer film 6 in an island shape having a substantially circular shape (diameter of 10 nm or less) by a vapor deposition apparatus. Here, the gap 8 between the islands of the hydrophilic film 7a is set to several nm by forming the thickness of the hydrophilic film 7a (MgF ₂ ) thin so as not to cover the surface of the optical multilayer film 6. Can be done. By making the gap 8 a few nm, which is sufficiently small with respect to the size of the sample loaded on the sample loading plate 1, the wettability of the sample loaded on the sample loading plate 1 can be made appropriate. .. Gap 8 between the islands of the hydrophilic film 7a (MgF ₂₎ is to be determined by the thickness of the hydrophilic film 7a formed on the optical multilayer film 6 (MgF _2), hydrophilic film 7a (MgF By changing the film thickness of ₂ ), it is possible to adjust the wettability of the sample loaded on the sample loading plate. This is because the gap 8 becomes wider when the film thickness of the hydrophilic film 7a (MgF ₂ ) formed on the optical multilayer film 6 is reduced, and the gap 8 becomes narrower when the film thickness of the hydrophilic film 7a (MgF ₂ ) is increased. Is. The method of forming the hydrophilic film 7a (MgF ₂ ) on the optical multilayer film 6 in an island shape is not limited to the above-mentioned method. For example, the hydrophilic film 7a (MgF ₂ ) is formed on the surface of the optical multilayer film 6. A mask may be placed on the surface of the optical multilayer film 6 to form the hydrophilic film 7a (MgF ₂ ) in an island shape. As a result, the gap 8 between the islands of the hydrophilic film 7a (MgF ₂ ) formed on the surface of the optical multilayer film 6 can be formed to a target size, and the sample loading plate 1 is loaded. It becomes easier to control the wettability of the sample. The gap (constant interval) between the islands is preferably several nm.

Next, as shown in FIG. 2C, after forming the hydrophilic film 7a (MgF ₂ ) in an island shape on the optical multilayer film 6, the surface of the hydrophilic film 7a (MgF ₂ ) and the hydrophilic film 7a (MgF ₂ ) are formed. _A hydrophobic film 7b (fluorine-based compound) is vapor-deposited so as to cover the surface of the optical multilayer film 6 on which ₂ ) is not formed.

[Step of removing hydrophobic membrane 7b: FIG. 2 (d)]
Next, as shown in FIG. 2 (d), the substrate 2 obtained by the above-mentioned method was formed on the surface of the hydrophilic film 7a (MgF ₂ ) by applying an impact such as ultrasonic vibration (not shown) to the substrate 2. The hydrophobic film 7b (fluorine-based compound) is removed, and the substrate 2 has a hydrophobic film 7b (fluorine-based compound) formed in the gap 8 between the hydrophilic film 7a (MgF ₂ ) and the hydrophilic film 7a (MgF ₂ ). .. Here, by applying an impact such as ultrasonic vibration to the substrate 2, the hydrophobic film 7b (fluorine-based compound) formed on the surface of the hydrophilic film 7a (MgF ₂ ) is removed and formed on the surface of the optical multilayer film 6. The reason why the hydrophobic film 7b (fluorine-based compound) is not removed will be described. This is because the adhesion between the hydrophilic film 7a (MgF ₂ ) and the hydrophobic film 7b (fluorine compound) is smaller than the adhesion between the surface of the optical multilayer film 6 and the hydrophobic film 7b (fluorine compound). The adhesion of the hydrophobic film 7b (fluorine compound) formed on the surface of the hydrophilic film 7a (MgF ₂ ) is extremely small so as to be removed by the impact of the ultrasonic vibration level. As a result, a hydrophilic film 7a (MgF ₂ ) and a hydrophobic film 7b (fluorine-based compound) are formed on the optical multilayer film 6, and the sample loaded on the sample loading plate 1 has an appropriate wettability. can do. The hydrophilic film 7a is not limited to MgF ₂ , and the hydrophobic film 7b is not limited to a fluorine-based compound. The adhesion between the hydrophilic film 7a and the hydrophobic film 7b is the adhesion between the outermost surface of the optical multilayer film 6 and the hydrophobic film 7b. It may be selected so as to be extremely small. For example, when the hydrophobic film 7b is a fluorine-based compound and the outermost surface of the optical multilayer film 6 is SiO ₂ , AlF and YF ₃ can be used as the hydrophilic film 7a.

[Groove formation step: FIG. 2 (e)]
Finally, as shown in FIG. 2E, the groove 4 is formed in the sample loading plate 1 in the groove forming step. For example, by a processing method such as a laser marking method, each film layer is peeled off until the surface of the substrate 2 is exposed through the hydrophilic film 7a (MgF ₂ ), the hydrophobic film 7b (fluorine compound), and the optical multilayer film 6. .. It is also desirable to process other address marks, barcode marks, etc. at the same time.

Although the embodiment of the sample loading plate and the manufacturing method thereof have been described above, the present invention is not limited to the manufacturing method of such an embodiment, and the idea of the present invention is in terms of detailed configuration, material, and quantity. It can be changed, added, or deleted arbitrarily as long as it does not deviate from. For example, the order of the hydrophilic film 7a (MgF ₂ ) and hydrophobic film 7b (fluorine-based compound) forming step and the groove forming step of this example may be changed. In this case, the hydrophilic membrane 7a (MgF ₂₎ and hydrophobic film 7b before the formation of the (fluorine-based compound) covering the surface of the groove with a mask or the like, the hydrophilic film 7a (MgF ₂₎ and hydrophobic film 7b (fluorine compound) Need to be formed.

In this embodiment, an example in which MgF ₂ which is a hydrophilic film 7a is provided on the second transparent layer 6d (SiO ₂ ) on the outermost surface of the optical multilayer film 6 formed on one surface of the substrate has been described. Even if the second transparent layer 6d (SiO ₂ ) on the outermost surface of the optical multilayer film 6 formed on one surface is not formed, and MgF ₂ which is a hydrophilic film 7a is provided on the second metal layer 6c (Ti). , The effect of the present invention can be obtained. As a result, it is not necessary to form the second transparent layer 6d (SiO ₂ ) on the optical multilayer film 6, which has advantages such as cost and workability.

In this embodiment, the sample loading plate used for the mass spectrometry of the MALDI method has been taken as an example to describe the sample loading plate according to the method for manufacturing the sample loading plate of the present invention. However, this sample loading plate is used for sample loading. Since the sample mounted on the plate can be properly wetted and spread, the sample loading plate used for mass spectrometry of the MALDI method is not limited to the same as the sample loading plate used for mass spectrometry of other methods. The same effect can be obtained even if a simple structure is adopted. For example, matrix-free laser desorption / ionization (LDI), surface-assisted laser desorption / ionization (SALDI), secondary ion mass spectrometry (SIMS), desorption electrospray ionization (DESI), electrospray support / It is also possible to apply the present invention to a sample loading plate used in a laser desorption / ionization method (ELDI) or the like.

1,100 Sample loading plate 2,110 Substrate 3,120 Laminated film 4 Groove 5 Island mark 6 Optical multilayer film 6a First metal layer (Ni)
6b First transparent layer (Al ₂ O ₃ )
6c Second metal layer (Ti)
6d 2nd transparent layer (SiO ₂ )
7a Hydrophilic membrane 7b, 122 Hydrophobic membrane 8 Gap 121 Conductive interference layer 200 Sample

Claims (4)

In the method for manufacturing a sample loading plate for loading a sample on a substrate, a step of forming an island-like hydrophilic film on one surface of the substrate, and the one surface of the substrate on which the hydrophilic film is not formed and the said A method for producing a sample loading plate, which comprises a step of forming a hydrophobic film on the surface of the hydrophilic film and a step of removing the hydrophobic film formed on the surface of the hydrophilic film. The method for manufacturing a sample loading plate according to claim 1, wherein the adhesion between the hydrophilic film and the hydrophobic film is smaller than the adhesion between the substrate and the hydrophobic film. The method for producing a sample loading plate according to claim 1, wherein an optical multilayer film is formed on the one surface of the substrate, and the hydrophilic film and the hydrophobic film are formed. The claim is characterized in that the outermost surface of the one surface of the substrate forming the hydrophilic film and the hydrophobic film is SiO ₂ , the hydrophilic film is MgF ₂ , and the hydrophobic film is a fluorine-based compound. Item 3. The method for manufacturing a sample loading plate according to any one of Items 1 to 3.

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