Ferritin rinse

Abstract

To provide a rinse liquid for ferritin which efficiently removes a ferritin layer formed on a peripheral part, lateral surface, and back surface of a substrate, and to provide a rinsing method.SOLUTION: An alkali aqueous solution is used as a rinse liquid. Preferably, an aqueous solution of aqueous ammonia, NaOH, KOH, Mg(OH) 2, or Ca(OH) 2 is used. The aqueous solution has a pH range of 11-12 and is, by weight, 0.085% to 8.5%, preferably 0.17% to 5.1%, more preferably 0.85% to 2.5%. A method includes: dropping a solution (having a ferritin concentration of 1-50 mg / ml) obtained by diluting ferritin with an ammonium acetate solution, onto a substrate; vaporizing the ammonium acetate solution by rotating the substrate; and thereafter rinsing an outer peripheral part, lateral surface, and back surface of the substrate by using an alkali aqueous solution of pH as a rinse liquid. Typically, rinsing conditions are as follows: a rotational frequency is 2,000 to 5,000 rpm; a liquid flow of the rinse is 1-50 ml / m; and rinsing time is 5-10 seconds.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rinse solution and a rinse method for removing ferritin that has adhered to the edge, side, and back surface of a substrate after ferritin has been applied to the substrate. [Background technology]

[0002] Ferritin is a spherical protein with a diameter of 8.5 to 12 nm, composed of 20 to 25 kDa subunits. Ferritin includes ferritin derived from microorganisms, animals, or plants. Examples of ferritin derived from microorganisms include ferritin derived from Helicobacter bacteria. Examples of ferritin derived from animals include human ferritin, mouse ferritin, and horse ferritin. Examples of ferritin derived from plants include soybean ferritin. Ferritin contains metal compounds, such as iron oxide, inside. Specifically, ferritin can be described as a soluble iron storage protein in which subunits are combined into a hollow, spherical three-dimensional structure. Note that ferritin without containing a metal compound inside and having a hollow interior is called "apoferritin." After arranging ferritin two-dimensionally on a substrate, the ferritin is removed by heating, and the metal oxide is reduced as needed, thereby easily obtaining quantum dots in which metal is arranged two-dimensionally on a substrate.

[0003] The method for two-dimensionally arraying ferritin on a substrate includes a coating step and a removal step. (1) About the coating process In the coating process, a solution containing a solvent and ferritin is coated onto a substrate, typically by spin coating. (2) Removal process In the removal step, the solvent is removed from the solution spread on the substrate. Specific methods for removing the solvent include centrifuging the substrate, evaporating the solvent from the substrate, etc. From the viewpoint of quickly removing the solvent, centrifuging the substrate is preferred.

[0004] In this way, ferritin can be two-dimensionally arranged on the substrate. After that, the ferritin is removed by heating, and if necessary, the metal oxide is reduced, whereby quantum dots consisting of metals two-dimensionally arranged on the substrate can be easily obtained.

[0005] When the solution containing the solvent and ferritin is applied to the substrate, it is applied to the entire surface of the substrate, and naturally, the edge portions of the substrate are also coated. It may also be coated on the side or back surface of the substrate. It is desirable to remove the material formed on the outer periphery of the substrate, as it can become a source of contamination in the next process or adhere to the substrate transfer arm, causing the substrate to fall off the transfer arm. Summary of the Invention [Problem to be solved by the invention]

[0006] Conventionally, no rinse solution has been known that can effectively remove the ferritin layer formed on the outer periphery, side, and backside of a substrate. The present invention provides a novel ferritin rinse solution and a rinsing method using the same. [Means for solving the problem]

[0007] The present invention provides a novel alkaline aqueous solution as a ferritin rinsing liquid, and a ferritin rinsing method using the same. In the present invention, any aqueous alkaline solution can be used, but preferably aqueous solutions of ammonia water, NaOH, KOH, Mg(OH)2, or Ca(OH)2 can be used. Preferably, an aqueous solution having a pH of 10-13, more preferably 11-12, is used.

[0008] In the production of electronic equipment-related parts, an alkaline aqueous solution that does not generate metal ions is preferably used, and an aqueous ammonia solution is most preferably used.

[0009] The preferred pH range is 11-12, and the weight percentage is 0.085 to 8.5%, more preferably 0.17 to 5.1%, and even more preferably 0.85 to 2.5%. An aqueous solution of an ammonium salt capable of generating ammonia or ammonium ions can also be used as the rinse solution. The concentration of the solution can be such that the total amount of ammonia and ammonium ions achieves the above-mentioned concentration range.

[0010] The rinsing solution of the present invention can be sprayed onto the outer periphery, sides, and backside of a substrate coated with ferritin using an appropriate nozzle, thereby removing ferritin from desired areas. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 shows the results of XPS measurement in the center of a substrate and in the peripheral portion of the substrate from which ferritin has been removed in an example. [Figure 2] Figure 2 is a photograph of the substrate after rinsing. DETAILED DESCRIPTION OF THE INVENTION

[0012] As a method for spraying a rinse solution, for example, a method for spraying a rinse solution for removing the edge portion of a resist can be used, and such methods are known to those skilled in the art. After the coating and solvent removal steps, the ferritin is heated to about 400°C to thermally decompose the protein.

[0013] Specifically, a solution of ferritin diluted with ammonium acetate (ferritin concentration 1-50 mg / ml) is dropped onto the substrate, and the substrate is rotated to evaporate the ammonium acetate. Then, an alkaline aqueous solution of the above pH is used as a rinse solution to rinse the outer periphery, sides, and backside of the substrate. Typical rinse conditions are a rotation speed of 2000-5000 rpm, a rinse solution flow rate of 1000 rpm, and a pH of 1000. ~ 50ml / m, rinse time 5 ~ The time is 10 seconds. Note that acetic acid is not an essential ingredient, and an aqueous solution of ferritin can also be used. [Example]

[0014] A solution of ferritin diluted with ammonium acetate was dropped onto the substrate, and the substrate was rotated to evaporate the ammonium acetate, thereby preparing the substrate. The outer periphery, sides, and backside of the substrate were rinsed with a 1.5 wt% aqueous ammonia solution at a rotation speed of 4000 rpm, a flow rate of the rinse solution of approximately 10 ml / m, and a rinsing time of 5 seconds. After rinsing, the substrate was dried at 4000 rpm for 10 seconds.

[0015] A photograph of the substrate after rinsing is shown in Figure 2. The color of the peripheral area of ​​the substrate is lighter, indicating that ferritin has been removed.

[0016] XPS (X-ray photoelectron spectroscopy) measurements were performed on the periphery and center of the sample after rinsing. The Al Kα source was used, and the removal of iron from the rinsed area was confirmed by detecting the peak due to the 2p orbital of Fe. The results are shown in Figure 1. Measurements of the central area showed Fe peaks at binding energies of approximately 726 eV and 712 eV, but no Fe peaks were observed in the rinsed peripheral area, indicating that ferritin had been removed by rinsing.

Claims

1. A method for removing both ferritin and the encapsulated metal oxide from any one of the edge portions, side surfaces, and back surface of a substrate, comprising removing the solvent from a substrate to which a solution containing ferritin encapsulating a metal oxide and a solvent has been applied, and then spraying an alkaline aqueous solution of pH 10-13 onto any one of the edge portions, side surfaces, and back surface of the substrate.

2. The method of claim 1 , wherein the aqueous alkaline solution comprises ammonium ions.

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