Manufacturing method of wafers with functional films

Abstract

This invention provides a method for manufacturing a wafer with a functional film. Even when a high-viscosity coating material is used as the coating material containing the functional film components in the manufacturing method of the wafer with a functional film, the functional film on the outer periphery of the wafer surface can be cleanly removed. The end face of the removed functional film has a good shape and can form a flat functional film. Furthermore, the beveled portion and back side of the wafer will not be contaminated by the coating residue. It is practically effective and the outer periphery of the wafer surface is exposed in a ring shape. The present invention discloses a method for manufacturing a wafer with a functional film applied to the outer periphery of the wafer surface exposed in a ring shape, characterized by comprising the following steps: Step (A) of spin-coating a high-viscosity coating material containing functional film components onto the wafer surface to form a coating film; Step (B-1) of removing the coating film from the outer periphery of the wafer surface while the wafer is rotated; Step (C) of heating the coating film on the wafer to form a flow-inhibiting film that inhibits the flowability of the coating film. After step (C), while rotating the wafer, a cleaning solution is supplied to the outer periphery of the wafer surface on which the flow inhibition film is formed, thereby removing the flow inhibition film on the wafer surface (D-1); and after step (D-1), the flow inhibition film on the wafer is heated to perform the function of the functional film components and form a functional film (E).

Description

Technical Field

[0001] This invention relates to a method for manufacturing a wafer with a functional film attached to its outer periphery exposed in a ring shape on the wafer surface. Prior Technology

[0002] In the rapidly developing semiconductor deposition technology of recent years, from the perspective of pursuing further deposition, the planar circuit substrate is deposited (layered) in three dimensions, and interconnected using silicon through-hole electrodes, while simultaneously depositing multiple layers. During this deposition, the side of each wafer used for deposition that is opposite to the already formed circuit surface (i.e., the back side) is thinned by grinding. Then, deposition is performed on the wafer after the layers have been thinned. Typically, before thinning, the wafer is attached to a support for polishing using a polishing apparatus. However, this attachment must be easily peeled off after polishing, so the wafer is temporarily attached to the support. Such a temporary attachment requires significant force to remove, which could damage the thinned wafer; therefore, easy removal from the support is crucial. On the other hand, it is undesirable for the substrate to detach or shift due to polishing stress when polishing the back side of the wafer. Therefore, the required performance is that it can withstand the stress during grinding and can be easily removed after grinding. Materials that can be temporarily attached in this way are known, for example, polysiloxane materials (see, for example, Patent Document 1). The aforementioned temporary bonding coating material is applied to the surface of a wafer to obtain a coated wafer. Heating the coated wafer causes the coating to perform its bonding function, forming a functional film with adhesive properties. As a result, a wafer with a functional film is obtained.

[0003] However, in the manufacturing of semiconductor devices, it is desirable to cleanly remove the functional film formed on the wafer edge (outer periphery). If the functional film is not removed and remains on the wafer edge, or if the end face of the functional film after removal does not have a good shape, problems such as dust generation due to friction of the functional film edge and contamination of the wafer transport arm may occur when using the wafer with the functional film attached in subsequent steps. Therefore, a method is desired that can manufacture wafers with functional films, in which the outer periphery of the wafer surface is exposed in a good annular shape, and the end face of the functional film after removal has a good shape.

[0004] As a method for manufacturing a coated wafer by removing the coating formed on the outer periphery of the wafer from the coating formed on the wafer surface, thereby exposing the outer periphery of the wafer surface in a ring shape, a method for manufacturing a coated wafer when the coating is a photoresist film is known (for example, see Patent Document 2). [Previous Technical Documents] [Patent Literature]

[0005] [Patent Document 1] International Publication No. 2017 / 221772 [Patent Document 2] International Publication No. 2015 / 121947 Summary of the Invention

[0006] [The technical problem that the invention aims to solve]

[0007] In Patent Document 2, which describes a photoresist film as the target coating, it is described that after heating (baking and drying), the coating is removed by spraying an edge rinsing solution or a back rinsing solution (see claim 1, paragraph

[0016] , etc.). Furthermore, Patent Document 2 describes that after removing the coating from the outer periphery of the wafer surface, the wafer with the coating is transported to an exposure apparatus for a photolithography step (see paragraph

[0023] ). That is, it is described that the coating removal is completed by a rinsing step, and then the next step is performed. As in Patent Document 2, when the coating is a photoresist film, in order to manufacture a wafer with a photoresist film covering the outer periphery of the wafer surface exposed in a ring shape, a rinsing step after heating is sufficient. Patent Document 2 describes that by performing a rinsing step after heating (baking and drying), a wafer with a photoresist film covering the outer periphery of the wafer surface can be formed. On the other hand, the functional film, which is the subject of this invention, performs its function by heating. Therefore, in order to obtain a wafer with a functional film, a heating step for forming the functional film must be performed. For example, in the case where the functional film is a material that can be temporarily bonded as described above, a coating material for temporary bonding is coated on the wafer surface to obtain a wafer with a coating, and then the coating is heated to obtain a wafer with a functional film that performs the bonding function. However, in cases where a coating containing a temporary adhesive material is heated and its components are hardened to form a functional film with adhesive properties, it is difficult to dissolve the functional film even with a rinsing solution because the functional film has hardened. Therefore, even if an attempt is made to remove the functional film by spraying a rinsing solution after its formation, the functional film cannot be completely removed. Therefore, in order to remove the functional film on the outer periphery of the wafer surface and obtain a wafer with the functional film exposed in a ring shape on the outer periphery of the wafer surface, a rinsing step must be performed before heating to harden the coating. Therefore, the present invention is not a method that does not require heat treatment after the rinsing step, as is the case where the coating is a photoresist film. Instead, it is a wafer manufacturing method specific to functional films, which differs from the procedures of methods targeting photoresist films. The present invention is a wafer manufacturing method that includes heat treatment for obtaining the functional film as a necessary procedure after the rinsing step.

[0008] Furthermore, there are many high-viscosity coating materials containing components that constitute the functional film, such as the temporarily bondable materials mentioned above. It is desirable that even when using such high-viscosity coating materials to manufacture wafers with functional films, it is possible to manufacture wafers with functional films where the functional film on the outer periphery of the wafer surface is cleanly removed and the outer periphery of the wafer surface is exposed in a good annular shape. However, after conducting research, the inventors found that when using a high-viscosity coating material as the coating material, it is not easy to cleanly remove the functional film on the outer periphery of the wafer surface and leave a functional film with a good end face shape. Furthermore, it was also found that when using high-viscosity coating materials to form a coating film on the wafer surface via spin coating, liquid splashing caused contamination on the back side of the wafer, which became a major problem.

[0009] Therefore, the object of the present invention is to provide a method for manufacturing a wafer with a functional film, wherein even when a high-viscosity coating material is used as the coating material containing the functional film components in the method for manufacturing a wafer with a functional film, the functional film on the outer periphery of the wafer surface can be cleanly removed, and the end face of the removed functional film has a good shape, forming a flat functional film. Furthermore, the beveled portion and back side of the wafer will not be contaminated by coating residue, which is practically effective and the outer periphery of the wafer surface is exposed in a ring shape. [Technical means]

[0010] In order to solve the above-mentioned problems, the inventors conducted repeated and in-depth research on the manufacturing method of wafers with functional films using high-viscosity coating materials containing functional film components. They discovered that, in addition to the heating used to form the functional film, a heating method to suppress the flowability of the coating film is also provided. These two heating steps are necessary. Furthermore, a cleaning (rinsing) step is performed before and after the initial heating step. This allows the functional film on the outer periphery of the wafer surface to be cleanly removed. In addition, the beveled portion and back side of the wafer are not contaminated by coating residue. This results in a wafer with a functional film that is practically effective, thus completing the present invention.

[0011] That is, the present invention includes the following states. [1] A method for manufacturing a wafer with a functional film attached to its outer periphery exposed in a ring shape, characterized by comprising the following steps: Step (A) involves spin-coating a high-viscosity coating material containing functional film components onto a wafer surface to form a coating film. Following step (A), while rotating the wafer, a cleaning solution is supplied to the outer periphery of the wafer surface on which the coating is formed, thereby removing the coating from the outer periphery of the wafer surface in step (B-1). Following the aforementioned step (B-1), the aforementioned coating on the wafer is heated to form a flow inhibition film that inhibits the flowability of the coating (C). Following step (C), while rotating the wafer, a cleaning solution is supplied to the outer periphery of the wafer surface where the aforementioned flow inhibition film is formed, thereby removing the aforementioned flow inhibition film from the wafer surface in step (D-1); and Following the aforementioned step (D-1), the aforementioned flow inhibition film on the aforementioned wafer is heated to perform the function of the aforementioned functional film components and form a functional film (E). [2] The method for manufacturing a wafer with a functional film as described in [1], wherein the viscosity of the aforementioned high-viscosity coating material is 1,000 to 15,000 mPa·s. [3] A method for manufacturing a wafer with a functional film as described in [1] or [2], wherein the constituent components of the aforementioned functional film contain a polymer. [4] The method for manufacturing a wafer with a functional film as described in [3], wherein the aforementioned polymer contains polysiloxane. [5] A method for manufacturing a wafer with a functional film as described in any one of [1] to [4], wherein, in step (D-1) of removing the aforementioned flow inhibition film from the wafer surface, while rotating the wafer, the following steps are performed: 1) supplying a cleaning solution to the outer periphery of the wafer surface on which the aforementioned flow inhibition film is formed, thereby removing the aforementioned flow inhibition film from the wafer surface (D-1-1); and 2) Move the supply position from the supply position of the cleaning solution in the aforementioned step (D-1-1) to a position outside the center of the aforementioned wafer, and supply the cleaning solution to the outer periphery of the aforementioned wafer surface on which the aforementioned flow inhibition film is formed at the supply position after the move, thereby removing the aforementioned flow inhibition film on the aforementioned wafer surface (D-1-2). [6] A method for manufacturing a wafer with a functional film as described in any one of [1] to [5], comprising: a step (B-2) of supplying a cleaning solution to the back side of the wafer after the aforementioned step (A) and before the aforementioned step (C) to clean the back side of the wafer. [7] A method for manufacturing a wafer with a functional film as described in any of [1] to [6], comprising: a step (D-2) of supplying a cleaning solution to the back side of the wafer after the aforementioned step (C) and before the aforementioned step (E) to clean the back side of the wafer. [8] A method for manufacturing a wafer with a functional film as described in any of [1] to [7], wherein the aforementioned cleaning solution is a hydrocarbon cleaning solution. [Effects of the Invention]

[0012] According to the present invention, a method for manufacturing a wafer with a functional film is provided. Even when a high-viscosity coating material is used as the coating material containing the functional film components in the manufacturing method of the wafer with a functional film, the functional film on the outer periphery of the wafer surface can be cleanly removed, and the end face of the removed functional film has a good shape, forming a flat functional film. Furthermore, the beveled portion and back side of the wafer will not be contaminated by coating residue. It is practically effective and the outer periphery of the wafer surface is exposed in a ring shape. Simple Explanation of the Diagram

[0013] [Figure 1] Figure 1 is a graph showing the measurement results of the film thickness variation of the functional film near the outer periphery of the silicon wafer with the functional film in Example 1 and Comparative Example 1. [Figure 2] Figure 2 is a graph showing the viscosity change of the dry film obtained in Reference Example 1 with temperature. Implementation

[0014] The following is a detailed description of the manufacturing method of the wafer with functional film according to the present invention. However, the description of the constituent elements described below is only an example of one embodiment of the present invention and is not limited to such content.

[0015] (Manufacturing method of wafers with functional films) The method for manufacturing a wafer with a functional film of the present invention involves manufacturing a wafer with a functional film that is exposed in a ring shape on the outer periphery of the wafer surface. The method for manufacturing a wafer with a functional film of the present invention includes: (I) Step (A) of spin-coating a high-viscosity coating material containing functional film components onto the surface of a wafer; (II) Step (B-1) after step (A), while rotating the wafer, a cleaning solution is supplied to the outer periphery of the wafer surface with the coating to remove the coating on the outer periphery of the wafer surface; (III) Step (C) involves heating the coating on the wafer after step (B-1) to form a flow inhibition film that suppresses the flowability of the coating. (IV) After step (C), while rotating the wafer, a cleaning solution is supplied to the outer periphery of the wafer surface on which the flow inhibition film is formed, thereby removing the flow inhibition film from the wafer surface (D-1); (V) Step (E) After step (D-1), the flow inhibition film on the wafer is heated to allow the functional film components to function and form a functional film.

[0016] The method for manufacturing a wafer with a functional film according to the present invention, which includes all the steps (I) to (V) above, is as shown in the following embodiments. It can manufacture a wafer with a functional film in the following way: the functional film on the outer periphery of the wafer surface is cleanly removed, and the outer periphery of the wafer surface is exposed in a good annular shape. Furthermore, the beveled portion and back side of the wafer are not contaminated by the coating residue, and it is effective in practical use. The superior effects of the present invention can be obtained by combining all the steps (I) to (V) above. For example, the wafer with a functional film that can be effectively used in practical applications, as required by the present invention, cannot be obtained if either step (B-1) of removing the coating with a cleaning solution in (II) above or step (D-1) of removing the flow inhibition film with a cleaning solution in (IV) above is missing. Furthermore, in this invention, the outer periphery of the wafer refers to the end of the wafer. For example, when the wafer is circular, with the center of the circle as 0 and the outer periphery as 100, it refers to a donut-shaped area of ​​50 to 100. Ideally, it refers to 70 to 100, more ideally, it refers to 90 to 100, and particularly ideally, it refers to 95 to 100.

[0017] Furthermore, an ideal example of the method for manufacturing a wafer with a functional film according to the present invention can be cited as follows: A method for manufacturing a wafer with a functional film, further comprising: (II-1) after step (A) and before step (C) above, supplying a cleaning solution to the back side of the wafer to clean the back side of the wafer (B-2); and A method for manufacturing a wafer with a functional film, further comprising: (IV-1) after step (C) and before step (E) above, supplying a cleaning solution to the back side of the wafer to clean the back side of the wafer (D-2).

[0018] The following is a detailed explanation of each step.

[0019] <(I)Step (A)> In step (A), a coating film composed of a high-viscosity coating material is formed on the wafer surface. The coating is formed by spin coating. High-viscosity coating materials contain functional film components.

[0020] In this invention, spin coating is used when coating a coating material onto the wafer surface, from the viewpoint of obtaining a uniform film easily and with good reproducibility. Spin coating is a method that involves supplying a coating material to the surface of a rotating wafer and using centrifugal force to spread the coating material, thereby coating the entire surface of the wafer.

[0021] <<Wafer>> There are no particular restrictions on the shape of the wafer; for example, it can be circular or polygonal, or any other shape other than a circle. Furthermore, if it is circular, it can be a perfect circle or an ellipse. Circular is generally the most common shape. A wafer may also have a portion that has been cut open. The notch may be, for example, a notch (U-shaped, V-shaped, or other grooves), or a straight section extending in a straight line (the so-called orientation plane). Wafers can be various substrates such as semiconductor substrates, glass substrates, photomask substrates, and FPD (Flat Panel Display) substrates. When the wafer is circular, the ideal diameter is approximately 200mm to 450mm. When the wafer is not circular, the ideal size is one that can be contained within a circle with a diameter of approximately 200mm to 450mm. The ideal thickness of a wafer is around 400μm to 1200μm. Wafers, such as semiconductor substrates, can be cited as typical examples, for example, silicon wafers with a diameter of about 300 mm and a thickness of about 770 μm, but are not limited to this.

[0022] <<High-viscosity coating materials>> High-viscosity coating materials contain functional film components. High-viscosity coating materials may contain solvents, such as when the material does not have sufficient viscosity for coating if it does not contain solvents. Functional membrane components are those that, when heated to a temperature above a specified level, function to form a functional membrane. More specifically, for example, it refers to components that, as described above, can temporarily bond and can be hardened by heating to form a functional membrane with adhesive properties. The components of a functional membrane can include, for example, conductive materials, insulating materials, adhesives, protective materials, and other materials. The components of a functional membrane ideally contain polymers. Specific examples of the components of a functional membrane include adhesive compositions containing adhesive components. Such adhesive components may include: polysiloxane-based adhesives, acrylic resin-based adhesives, epoxy resin-based adhesives, polyamide-based adhesives, polystyrene-based adhesives, polyimide adhesives, phenolic resin-based adhesives, etc., but are not limited to these. Ideally, the functional membrane should contain thermosetting resin components of polysiloxane resin.

[0023] The viscosity of the high-viscosity coating material used in this invention refers to a value of 1,000 mPa·s or higher as measured by an E-type viscometer. Furthermore, from the viewpoint of forming a coating film by spin coating, the viscosity of the high-viscosity coating material is preferably 15,000 mPa·s or lower. From the viewpoint of ideally exposing the outer periphery of the wafer surface in a ring shape, and from the viewpoint of forming a functional film with excellent planarity on the wafer with good reproducibility, the viscosity of the high-viscosity coating material used in this invention is ideally 1,000 to 12,000 mPa·s, more ideally 1,000 to 10,000 mPa·s, and even more ideally 1,500 to 10,000 mPa·s.

[0024] The concentration of the functional film components in high-viscosity coating materials is ideally around 40-100% by mass. Here, the functional film components refer to components other than the solvent contained in the high-viscosity coating material. Furthermore, in the case of high-viscosity coating materials without solvents, a certain component of the functional film may simultaneously perform the function of the final functional film and the same function as the solvent in the high-viscosity coating material. In this case, by containing such a component, that is, by containing a component that exhibits viscosity adjustment capabilities, the viscosity of the high-viscosity coating material, even without solvents, can remain within the aforementioned range. Moreover, by reducing fluidity through the evaporation of a portion of this component upon heating, a fluidity-inhibiting film is achieved, and the remaining portion, due to its residue within the film, ultimately constitutes the functional film.

[0025] <<Solvent>> In the case of high-viscosity coating materials containing solvents, the type of solvent is not particularly limited and can be appropriately selected according to the purpose. For example, it is ideal to avoid organic solvents with boiling points higher than those required for the curing of the functional film components. This is because, in the case of organic solvents with boiling points higher than those required for the curing of the functional film components, depending on the thickness of the coating and the amount of solvent used, it may be impossible to remove the solvent from the coating to a degree sufficient to reduce its fluidity by heating. Therefore, the amount of organic solvents with boiling points higher than those required for the curing of the functional film components should be 50% by mass or less, ideally 30% by mass or less, more ideally 20% by mass or less, and even more ideally 10% by mass or less of the total solvent content. The solvent can be appropriately selected by considering the solubility of the functional membrane components, the relationship between their boiling points and the temperature required to harden the functional membrane components, and the desired membrane thickness. Solvents can be used alone or in combination of two or more.

[0026] In cases where high-viscosity coating materials contain solvents, specific examples of solvents used include: straight-chain or branched aliphatic saturated hydrocarbons such as hexane, heptane, octane, nonane, decane, undecane, dodecane, and isododecane; cyclic aliphatic saturated hydrocarbons such as cyclohexane, cycloheptane, cyclooctane, isopropylcyclohexane, and p-menthane; cyclic aliphatic unsaturated hydrocarbons such as limonene; aromatic hydrocarbons such as benzene, toluene, o-xylene, m-xylene, p-xylene, symmetrical trimethylbenzene, 1,2,4-trimethylbenzene, cumene, 1,4-diisopropylbenzene, and p-isopropyltoluene; and MIBK (methyl isobutyl ketone), ethyl methyl ketone, acetone, diisobutyl ketone, 2-octanone, 2-nonanone, and 5- Ketones such as nonyl ketones, cycloalkyl ketones such as cyclohexanones, aliphatic saturated hydrocarbon ketones such as isophorones, and aliphatic unsaturated hydrocarbon ketones such as alkenyl ketones; ethers such as dialkyl ethers, di(n-propyl) ethers, di(n-butyl) ethers, and di(n-pentyl) ethers; ethers such as tetrahydrofuran and dioxane cyclic alkyl ethers; sulfides such as dialkyl sulfides, di(n-propyl) sulfides, and di(n-butyl) sulfides; acetylamines such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylisobutylamide, N-methylpyrrolidone, and 1,3-dimethyl-2-imidazolium ketone; nitriles such as acetonitrile and 3-methoxypropionitrile; ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,3-butanediol, and 2,3-butanediol. Polyols such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, etc., diol monoalkyl ethers such as diethylene glycol monophenyl ether, etc., diol monoaryl ethers such as diethylene glycol monoaryl ether; alkyl alcohols such as methanol, ethanol, propanol, etc., linear or branched alkyl monools, cyclohexanol, etc., cyclic alkyl alcohols such as cyclohexanol, etc., monools other than alkyl alcohols such as diacetone alcohol, benzyl alcohol, 2-phenoxyethanol, 2-benzyloxyethanol, 3-phenoxybenzyl alcohol, tetrahydrofurfuryl alcohol, etc.; diols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, tripropylene glycol, hexanediol, triethylene glycol, 1,2-butanediol, 2,3-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, etc.; diols such as ethylene glycol monohexyl ether, propylene glycol monobutyl ether. Diethylene glycol monoethyl ether, dipropylene glycol monobutyl ether, ethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, dipropylene glycol monomethyl ether, diethylene glycol monopropyl ether (propyl carbitol), diethylene glycol monohexyl ether, 2-ethylhexyl carbitol, dipropylene glycol monopropyl ether, tripropylene glycol monomethyl ether, diethylene glycol monomethyl ether, tripropylene glycol monobutyl ether, etc., diol monoalkyl ethers of diols, diol monoaryl ethers of diols, 2-phenoxyethanol, etc.; diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol dibutyl ether, dipropylene glycol methyl n-propyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, etc., diol dialkyl ethers of diols, etc., diol diethers;Diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, etc., and other glycol monoalkyl ether acetates, etc.; cyclic carbonates such as ethyl carbonate, propyl carbonate, ethylene carbonate, etc.; esters such as ethyl acetate, butyl acetate, pentyl acetate, etc., etc.

[0027] In step (A), a coating film is formed by applying a high-viscosity coating material to the wafer surface using a spin coating method. A coating is a film obtained by coating a coating material without intentionally heating it. A coating can be obtained by supplying a coating material to the surface of a rotating wafer. More specifically, for example, a coating can be formed on the wafer surface by supplying a high-viscosity coating material to the rotating wafer from a material supply nozzle positioned above the wafer. The thickness of the coating can be adjusted by the concentration and viscosity of the solid components of the coating material, as well as the rotation speed when the wafer is rotated. The wafer rotation speed can be the speed commonly used, such as around 500~4,000 rpm. The supply of coating materials is appropriately determined by taking into account the area of ​​the wafer surface in order to form a coating film on the entire wafer surface.

[0028] <(II) Step (B-1)> In step (B-1), a portion of the coating film formed in step (A) is removed. Specifically, while rotating the wafer, a cleaning solution (rinsing solution) is supplied to the outer periphery of the wafer surface with the coating, thereby removing the coating from the outer periphery of the wafer surface. More specifically, for example, the coating formed on the wafer surface can be dissolved and removed by spraying cleaning fluid from a cleaning fluid supply nozzle positioned above the wafer onto the rotating wafer. The method of spraying and supplying the cleaning solution can be, for example, the commonly known method of edge cleaning (EBR) used to clean the coating on the periphery of the wafer surface with rinsing solution.

[0029] By performing step (B-1), the quality of the flow inhibition film on the outer periphery of the wafer surface can be improved in step (D-1) described later. Furthermore, by performing step (B-1), contamination caused by coating residue on the beveled edges and back side of the wafer can be effectively prevented. The bevel of a wafer refers to the tilted side (side) of the wafer.

[0030] <<Cleansing Solution>> The cleaning solution (rinsing solution) can be selected judiciously as long as it does not damage the wafer and can effectively dissolve and remove the coating. A more suitable choice is made considering the types and concentrations of functional film components in the high-viscosity coating material used, as well as the thickness of the coating. The cleaning solution may contain components other than solvents such as salts, but from the point of view of avoiding or inhibiting unnecessary contamination of the substrate with the functional film and the deterioration of the functional film, it is generally ideal to consist only of solvents. From the viewpoint that it can be easily dried and removed by heating, the solvent contained in the cleaning solution should ideally be free of organic solvents with boiling points higher than those required for the components of the hardening functional film. In addition, it should ideally be highly volatile and have excellent drying properties. Specific examples of solvents contained in the cleaning solution can be those that are the same as the specific examples of solvents listed above in cases where the solvent is contained in a high-viscosity coating material. Solvents can be used alone or in combination of two or more.

[0031] Cleaning solutions can be commercially available, such as Shellsol MC311 (main component: isoparaffin), MC421 (main component: isoparaffin), MC531 (main component: isoparaffin), MC611 (main component: paraffin), MC721 (main component: n-paraffin), and MC811 (main component: mixture (paraffin / cycloparaffin / aromatic hydrocarbon)) manufactured by Tobu Chemical Co., Ltd., etc., which are hydrocarbon-based cleaning solutions (detergents), but are not limited to these. Among them, the most ideal cleaning solution is a hydrocarbon-based cleaning solution containing aliphatic hydrocarbons that can remove a wide range of functional membrane components.

[0032] The location for supplying the cleaning solution in step (B-1) is not particularly limited as long as it can remove the coating on the outer periphery of the wafer. For example, when using a circular wafer, the final exposed width, the coating removal power of the cleaning solution, and the wetting and spreading properties on the wafer can be considered. For example, when the center of the circle is 0 and the outer periphery is 100, it is preferable to supply the cleaning solution from above the wafer surface to a donut-shaped area of ​​70-100.

[0033] There are no particular restrictions on the shape of the cleaning solution supply nozzle, and any suitable option can be selected. However, in order to efficiently dissolve the coating, the cleaning solution supply nozzle is ideally an injection type nozzle, and when spraying the cleaning solution, it is ideal for the cleaning solution to be sprayed onto the wafer in a rod shape. Furthermore, the position of the cleaning solution supply nozzle does not necessarily have to be above the wafer. For example, in the case where the wafer surface is facing down and the cleaning solution is supplied, the cleaning solution supply nozzle can also be positioned below the wafer surface, supplying the cleaning solution from below the wafer surface.

[0034] <(II-1) Step (B-2)> In this invention, a step (B-2) may also be included, which involves supplying a cleaning solution to the back side of the wafer after step (A) and before step (C) to clean the back side of the wafer. In step (B-1) above, when removing the coating, a step (B-2) can be performed where cleaning solution is supplied not only from the wafer surface side but also from the wafer back side. More specifically, for example, cleaning fluid can be sprayed onto the rotating wafer from a cleaning fluid supply nozzle located on the back (below) of the wafer. The method of spraying and supplying the cleaning solution can be, for example, the commonly known method of back-side cleaning (BSR) used to clean the back side of a wafer with a rinsing solution.

[0035] By performing steps (B-1) and (B-2), even when a high-viscosity coating material is applied to the back of the wafer and the material adheres to the back of the wafer, the adhered material can be removed and a clean back surface can be maintained. As a result, even if the back of the wafer comes into contact with the surface of other objects, contamination of those other objects due to contact can be avoided. When cleaning solution is supplied to the back side of a wafer, the supply area can be the entire back side of the wafer or a portion thereof. When cleaning solution is supplied to a portion of the back side of a wafer, for example, if the wafer is circular, the cleaning solution can be supplied to its outer periphery and can be supplied to the aforementioned donut-shaped area. By performing steps (B-1) and (B-2), contamination caused by coating residue on the beveled part and back side of the wafer can be prevented more effectively. Therefore, in this invention, it is more ideal to perform step (B-2) in addition to step (B-1).

[0036] <(III) Step (C)> In step (C), the coating on the wafer is heated to form a flow inhibition film that inhibits the flow of the coating. In this invention, in addition to the heating step (E) for forming the functional film, a heating step (C) is also required for suppressing the flowability of the coating film. By including the two heating steps (C) and (E), a practically effective wafer with a functional film, which is the object of this invention, can be obtained. The heating in step (C) is performed to make the coating film lose its fluidity before step (C). For example, by heating a highly fluid coating film in step (C), a fluidity-inhibiting film that has lost its fluidity can be obtained. A flow-inhibiting film refers to a film obtained by intentionally heating a coating. It is a film whose flowability is reduced or lost compared to the coating before heating. Specific examples of flow-inhibiting films that have lost their flowability include, for instance, dried films. In the case of coating materials containing solvents, by heating in step (C), a dried film (or a solid film in which the solvent in the coating has evaporated and solidified) can be obtained where some or all of the solvent in the coating has evaporated. The viscosity of the flow inhibition film obtained by step (C) measured by a rheometer at a temperature of 25°C is generally around 30,000 to 1,000,000 mPa·s. However, from the viewpoint of obtaining a wafer with a functional film that is ideally exposed in a ring shape on the outer periphery of the wafer surface with good reproducibility, its lower limit is ideally 40,000 mPa·s, and more ideally 50,000 mPa·s; its upper limit is 800,000 mPa·s in some samples and 500,000 mPa·s in other samples.

[0037] When high-viscosity coating materials are spin-coated onto wafers, the high viscosity of the coating means that rotation alone will not cause the coating to lose its fluidity and will maintain its original state. This is especially true when the high-viscosity coating material contains solvents; rotation alone will prevent the solvents from drying sufficiently, and the coating's fluidity will not be lost. Even when attempting to remove the ends of such a fluid coating from the wafer using a cleaning solution, the centrifugal force of the rotating wafer causes new coating to be supplied from the inside immediately after the ends are removed, making clean removal impossible. However, by heating in step (C) to form a flow inhibition film that has lost its fluidity (e.g., a dry film (solid film)), the centrifugal force of the wafer rotation will not cause a situation where a new film is immediately supplied from the inside after the film at the end is removed. Therefore, by using a cleaning solution to remove its end, the flow inhibition film on the outer periphery of the wafer surface can be cleanly removed, and a flow inhibition film with a good end face shape remains. Furthermore, the flow-inhibiting membrane obtained in step (C) has not yet undergone sufficient hardening of its functional membrane components, nor has it reached the level where these components can perform their functions. Because the hardening of the functional membrane components is incomplete, it exhibits sufficient solubility in the cleaning solution.

[0038] The heating temperature in step (C) varies depending on the curing temperature and film thickness required for the functional film components of the high-viscosity coating material, and therefore cannot be specified uniformly, but it is approximately less than 150°C, ideally less than 130°C. Furthermore, the heating time varies depending on the heating temperature and therefore cannot be specified uniformly, but it is approximately 10 seconds to 10 minutes. Heating can be performed, for example, using an oven or a heating plate.

[0039] <(IV) Step (D-1)> In step (D-1), a portion of the flow inhibition membrane obtained in step (C) is removed. Specifically, while rotating the wafer, a cleaning solution (rinsing solution) is supplied to the outer periphery of the wafer surface on which the flow inhibition film is formed, thereby removing the flow inhibition film on the outer periphery of the wafer surface. More specifically, for example, the flow inhibition film formed on the wafer surface can be dissolved and removed by spraying cleaning fluid from a cleaning fluid supply nozzle positioned above the wafer onto the rotating wafer. The method of spraying and supplying the cleaning solution, for example as described in the text of step (B-1) of (II) above, may use a method commonly known as EBR.

[0040] In step (D-1), the ends of the flow inhibition film (e.g., a dried film (solid film)) that has lost its flowability in step (C) are removed using a cleaning solution. Therefore, by step (D-1), the flow inhibition film on the outer periphery of the wafer surface can be cleanly removed, and a flow inhibition film with a good end face shape can remain.

[0041] The cleaning solution used in step (D-1) can be the same as or different from the cleaning solution used in step (B-1), but from the point of view that the process conditions become simpler, it is ideal for the two cleaning solutions to be the same.

[0042] The ideal example of removing the flow inhibition film on the wafer surface (D-1) can be described by performing step 1) (D-1-1) and step 2) (D-1-2) below. That is, step (D-1) is more ideally performed while the wafer is being rotated: 1) Step (D-1-1) of supplying a cleaning solution to the outer periphery of the wafer surface on which the flow inhibition film is formed, thereby removing the flow inhibition film from the wafer surface; and 2) Moving the supply position from the supply position of the cleaning solution in the aforementioned step (D-1-1) to a position outside the center of the wafer, and supplying the cleaning solution to the outer periphery of the wafer surface on which the flow inhibition film is formed at the supply position after the move, thereby removing the flow inhibition film on the wafer surface (D-1-2).

[0043] In step (D-1), changing the supply position of the cleaning solution and supplying the cleaning solution at different supply positions to remove the flow inhibition film is more ideal from the viewpoint of removing the flow inhibition film on the outer periphery of the wafer surface more cleanly. In step (D-1-2), the position of the washing solution supply is moved to a position further out than in step (D-1-1), and the washing solution is supplied to the flow inhibition membrane again to remove the flow inhibition membrane. This is to ensure that, for example, in step (D-1-1), the membrane becomes wet and liquid seeps out from the membrane due to partial contact between the washing solution and the flow inhibition membrane, the seeped membrane portion is removed. Therefore, by performing steps (D-1-1) and (D-1-2), the flow inhibition film on the outer periphery of the wafer surface can be removed more effectively and cleanly, while leaving a flow inhibition film with a good end face shape. Furthermore, in order to change the supply position of the cleaning solution and supply the cleaning solution at different supply positions, the above steps (D-1-1) and (D-1-2) are explained using two different supply positions as an example. However, the number of different supply positions is not limited to two, but can be three or more. For example, steps (D-1-3), (D-1-4)... can also be further set.

[0044] <(IV-1) Step (D-2)> In this invention, a step (D-2) may also be included, which involves supplying a cleaning solution to the back side of the wafer after step (C) and before step (E) to clean the back side of the wafer. In step (D-1) above, when removing the flow inhibition film, a step (D-2) can be performed where cleaning solution is supplied not only from the wafer surface side but also from the wafer back side. More specifically, for example, cleaning fluid can be sprayed onto the rotating wafer from a cleaning fluid supply nozzle located on the back (below) of the wafer. The method of spraying and supplying the cleaning solution, for example as described in the text of step (B-2) of (II-1) above, may use a commonly known method as BSR.

[0045] By performing steps (D-1) and (D-2), when a high-viscosity coating material is applied to the back side of the wafer and the material adheres to the back side, the material adhering to the back side can be removed even if step (B-2) is not performed, or if step (B-2) is performed but the adhered material cannot be completely removed, thus maintaining a clean back side. As a result, even if the back side of the wafer comes into contact with the surface of other objects, contamination of those other objects due to contact can be avoided. Furthermore, undesirable conditions caused by unnecessary material adhesion to the back side of the wafer with the functional film can be avoided. When cleaning solution is supplied to the back side of a wafer, the supply area can be the entire back side of the wafer or a portion thereof. When cleaning solution is supplied to a portion of the back side of a wafer, for example, if the wafer is circular, the cleaning solution can be supplied to its outer periphery and can be supplied to the aforementioned donut-shaped area. By performing steps (D-1) and (D-2), contamination caused by residual flow inhibition film on the bevel and back of the wafer can be prevented more effectively. Therefore, in this invention, it is more ideal to perform step (D-2) in addition to step (D-1).

[0046] <(V)Step(E)> In step (E), the flow inhibition film on the wafer is heated to give full play to the function of the components of the functional film, thereby obtaining the functional film. For example, the components of a functional membrane are hardened to form a functional membrane. More specifically, for example, in the case where the functional membrane is an adhesive membrane, the components with adhesive properties are hardened to allow the adhesive properties to be exerted and to form a functional membrane (adhesive membrane). A functional membrane is a membrane obtained by intentionally heating a flow-inhibiting membrane. It refers to a membrane that has been heated to perform the functions of its constituent components. For example, functional membranes are hardened by heating, thus they do not exhibit sufficient solubility in cleaning solutions.

[0047] The heating temperature in step (E) varies depending on the curing temperature and film thickness required for the functional film components of the high-viscosity coating material, and therefore cannot be specified uniformly, but it is approximately 150°C or higher, ideally 180°C or higher. Furthermore, the heating time varies depending on the heating temperature and therefore cannot be specified uniformly, but it is approximately 1 to 30 minutes. Heating can be performed, for example, using an oven or a heating plate.

[0048] One example of the functional film of the present invention is a film with a thickness of 10 μm or more after heating in step (E), and a relatively thick film is considered as the film formed on the surface of a semiconductor wafer. Ideally, the thickness of a functional membrane should be 20 μm or more, more ideally 30 μm or more, and even more ideally 40 μm. On the other hand, considering practical convenience, the thickness of a functional membrane should be 500 μm or less, ideally 300 μm or less, more ideally 200 μm or less, even more ideally 100 μm or less, and especially ideally 70 μm or less.

[0049] By proceeding through step (E), a wafer with a functional film can be obtained as follows: the functional film on the outer periphery of the wafer surface is cleanly removed, and the outer periphery of the wafer surface is exposed in a good annular shape. Furthermore, the end face of the removed functional film has a good shape. The wafer with a functional film is also free from contamination due to residual coating and is practically effective. According to the present invention, for example, when the wafer is circular, a wafer with a functional film attached can be manufactured in which the outer periphery of the wafer surface is exposed in a ring shape (donut shape). Furthermore, the exposed area formed at this time, with the center of the circle as 0 and the outer periphery as 100, can generally be a donut-shaped area of ​​50 to 100, in some samples it can be a donut-shaped area of ​​70 to 100, in other samples it can be a donut-shaped area of ​​90 to 100, and in further other samples it can be a donut-shaped area of ​​95 to 100.

[0050] The viscosity of the functional film obtained in step (E), as measured by a rheometer under the heating temperature conditions of that step, generally exceeds 1,000,000 mPa·s. However, from the viewpoint of suppressing deformation of the functional film and misalignment of the wafer or substrate when bonding the wafer with the functional film obtained in the manufacturing method of the present invention to a substrate by clamping the functional film, it is ideally 2,000,000 mPa·s or more, more ideally 4,000,000 mPa·s or more, even more ideally 6,000,000 mPa·s or more, and even more ideally 8,000,000 mPa·s or more. 00,000 mPa·s or more; further, from the viewpoint that when a wafer and a support substrate are bonded together in a manner that clamps the functional film to form a laminate, and when the wafer is ground and thinned, for example, by rotating it, the wafer does not shift, the ideal value is 10,000,000 mPa·s or more, more ideally 20,000,000 mPa·s or more, even more ideally 40,000,000 mPa·s or more, even more ideally 80,000,000 mPa·s or more, and even more ideally 100,000,000 mPa·s or more. Furthermore, the viscosity of the functional membrane measured by a rheometer under the heating temperature conditions in step (E) can be obtained, for example, by placing an appropriate amount of dried membrane into a metal cup with a diameter of 65 mm, placing a metal plate with a diameter of 25 mm on top to make a test sample, and placing the test sample on a dual-drive rheometer MCR302 manufactured by Anton Paar Corporation, with a temperature increase of 5°C per minute.

[0051] Incidentally, the functional film of the present invention, for example, is a bonding film for temporary bonding. As described above, this functional film is used to bond a device wafer with circuits formed and a support wafer (support substrate) as a support body in order to thin the wafer. If necessary, the device wafer and the support wafer are bonded together with other films with the functional film to support the support wafer side and polish the device wafer. One example of using the wafer with the functional film of the present invention in this manner is to use a wafer with a flow inhibition film obtained through the above steps (D-1) and / or the above steps (D-1) and (D-2). The wafer with the flow inhibition film and a support wafer serving as a support are sandwiched between the flow inhibition film and placed opposite each other. By applying the heating of step (E) in this state, the functional film is formed and the device wafer and the support wafer are bonded together. At this time, if necessary, pressure is applied in the vertical direction of the wafer. Since the wafer attached to the wafer support device is a wafer with the functional film on the outer periphery of the wafer surface cleanly removed and the outer periphery of the wafer surface is exposed in a good ring shape, there is no need to worry about dust being generated or the wafer transport arm being contaminated by rubbing the edge of the functional film during subsequent operation steps such as the wafer polishing device, and good operation can be performed. As described above, the wafer manufacturing method with functional film according to the present invention can prevent the problem of the film formed on the wafer with circuit board not being cleanly removed from the outer periphery of the wafer in the subsequent steps after forming electronic circuits on the surface of a semiconductor wafer. [Example]

[0052] The following examples illustrate the invention in a more detailed manner, but the scope of the invention is not limited to these examples. Furthermore, the apparatus used in the embodiments is as follows. (1) Coating device: Litho Spin Cup 200C manufactured by Litho Tech Japan (2) Film thickness measurement: Filmetrics F50 optical interferometer thickness gauge manufactured by Filmetrics Co., Ltd. (3) Observation of membrane changes (membrane shape): DektakXT-A probe profiling system manufactured by Bruker Corporation. (4) Membrane viscosity (dry film viscosity) measurement: Anton Paar MCR302 dual-drive rheometer. (5) Viscosity measurement of coating materials (coating components): TVE-22H and TVE-35H E-type viscometers manufactured by Toki Industries, Ltd.

[0053] (Example 1) Prepare a coating composition containing a thermosetting resin component of polysiloxane resin and solvents of menthol and n-decane, with a viscosity of 2,500 mPa·s as measured by an E-type viscometer. The coating composition was spin-coated (800 rpm, 30 seconds) onto the surface of an 8-inch silicon wafer to form a coating film. While the coated silicon wafer is rotated (800 rpm, 10 seconds), a hydrocarbon-based cleaning solution (Shellsol MC421 manufactured by Eastern Chemical Co., Ltd., hereinafter the same) is continuously sprayed in a rod shape from an injection nozzle and supplied to the outer periphery of the wafer surface and the outer periphery of the back side, thereby removing the coating on the outer periphery of the wafer surface and cleaning the outer periphery of the back side. Then, the coated silicon wafer is rotated (800 rpm, 30 seconds) and dried by rotation, and then heated at 120°C for 90 seconds to obtain a silicon wafer with a flow inhibition film (also known as a silicon wafer with a drying film). While rotating the silicon wafer with the dried film (800 rpm, 60 seconds), a hydrocarbon-based cleaning solution is continuously sprayed in a rod shape from an injection nozzle and supplied to the outer periphery of both the surface and back of the wafer, thereby removing the dried film from the outer periphery of the wafer surface and cleaning the outer periphery of the back. Next, while continuing to rotate the silicon wafer, the spraying of the cleaning solution is temporarily stopped, and the spray position of the cleaning solution nozzle that sprays the cleaning solution onto the wafer surface is moved outward by 1.5 mm. Then, the cleaning process is restarted, with the silicon wafer with the dried film rotating (800 rpm, 60 seconds) while the hydrocarbon-based cleaning solution is continuously sprayed in a rod shape from an injection nozzle and supplied to the outer periphery of both the surface and back of the wafer, thereby removing the dried film from the outer periphery of the wafer surface and cleaning the outer periphery of the back. Then, the silicon wafer with the drying film is rotated (1500 rpm, 30 seconds) and dried by rotation, and then heated at 200°C for 10 minutes to obtain a silicon wafer with a functional film.

[0054] (Comparative Example 1) The process of preparing the coating composition and heating at 120°C for 90 seconds, as described in Example 1, was repeated to obtain a silicon wafer with a dry film. Next, the silicon wafer with the dry film was heated at 200°C for 10 minutes to obtain a silicon wafer with a functional film.

[0055] (Evaluation of film thickness on silicon wafers with functional films) For the silicon wafers with functional films obtained in Example 1 and Comparative Example 1, the film thickness at 17 locations on the functional films was measured. The differences between the average film thickness, the maximum film thickness, and the minimum film thickness are shown in Table 1. From these results, it can be confirmed that the two functional films obtained in Example 1 and Comparative Example 1 have the same film thickness. The silicon wafer with the functional film in Example 1, as shown in Table 1 below, can form a flat functional film.

[0056] [Table 1]

[0057] (Evaluation of the shape of the functional film on the outer periphery of the silicon wafer with the functional film and the back side of the wafer) The thickness variation of the functional film on each silicon wafer with a functional film obtained in Example 1 and Comparative Example 1 was observed from the vicinity of the outer periphery to the center. The results are shown in Figure 1. As shown in Figure 1, in Example 1, almost no change in the thickness of the functional film was observed up to approximately 2 mm from the measurement start point on the wafer end face. Subsequently, a sharp change in film thickness of approximately 40 μm was confirmed. This means that no functional film was formed up to approximately 2 mm from the measurement start point, i.e., the silicon wafer was exposed. It also means that a functional film of the expected thickness (approximately 40 μm) was formed from the area approximately 2 mm from the center. On the other hand, in Comparative Example 1, no film thickness change was observed that was equivalent to the expected film thickness (about 40 μm) as observed in Example 1, and no substantial film thickness change was observed thereafter until a film thickness reduction of about 25 μm was confirmed in an area about 2 mm from the measurement start point on the wafer end face. Given that the thickness of each functional film in Example 1 and Comparative Example 1 is the same, this means that the thickness of the functional film on the outer periphery of the wafer in Comparative Example 1 is thicker than the expected thickness (about 40 μm). In Example 1, the silicon wafer with the functional film attached has a good shape on the end face after the functional film is removed, and the functional film on the outer periphery of the wafer surface is cleanly removed. Furthermore, visual observation of the back side of the silicon wafer with the functional film in Example 1 did not reveal any contamination such as material adhesion. The silicon wafer with the functional film in Example 1 is a good silicon wafer with the functional film attached and no contamination on the back side.

[0058] (Refer to Example 1) The drying film was peeled off from the silicon wafer with the drying film obtained in Example 1, and placed into a 65 mm diameter metal cup. A 25 mm diameter metal plate was placed on top to prepare a test sample. The test sample was placed on an Anton Paar MCR302 dual-drive rheometer, and the viscosity of the drying film was measured at a heating rate of 5°C per minute. The viscosity change of the dried film with temperature is shown in Figure 2. As shown in Figure 2, it is confirmed that the viscosity of the dried film increases sharply above 120°C. Furthermore, when the measured film is a heated dry film, there should be a decrease in viscosity due to the softening of the polymer constituting the dry film (A) caused by heating, and an increase in viscosity due to the cross-linking of the polymer, which is the main component of the dry film, caused by heating (B). On the other hand, when the coating film is heated at a temperature lower than the temperature at which the cross-linking occurs, there should be a decrease in viscosity due to the phenomenon (A) caused by heating, and an increase in viscosity due to the evaporation of the solvent (C) caused by heating. As mentioned above, in the viscosity measurement results of the dry film shown in Figure 2, in the region below 120°C, since the decrease caused by the phenomenon (A) is dominant, the viscosity at 120°C is lower than the viscosity at lower temperatures. However, when the actual coating film is heated, since the increase in viscosity caused by the phenomenon (C) is dominant, the viscosity at 120°C is higher than the viscosity at lower temperatures.

[0059] That said, the functional film of the present invention, for example, is a temporary bonding film. As described above, this functional film is used to bond a device wafer with circuitry and a support wafer as a support in order to thin the wafer. The device wafer and the support wafer are bonded together with the functional film to support the support wafer side and polish the device wafer. At this time, if the viscosity of the functional film is low, the wafer will shift during polishing of the device wafer and the function cannot be displayed. Therefore, heating to 150°C or higher is generally required to display the function. On the other hand, if the viscosity of the functional film becomes high, cross-linking will occur, making it impossible to dissolve and remove the film using a cleaning solution. Since the functional film of the present invention exhibits the film characteristics shown in FIG2, it is known that in order to manufacture a wafer with a functional film attached to the outer periphery of the wafer surface exposed in a ring shape, it is necessary to include a first heating step (equivalent to step (C) above) for making a dry film soluble in the cleaning solution, and a second heating step (equivalent to step (E) above) for making the functional film.

[0060] Next, by comparing the following Reference Example 2 and the following Comparative Reference Example 1, it is shown that by performing steps (B-1) and (B-2) between step (A) and step (C), a high-quality wafer with a functional film that is free from contamination on the bevel and back side of the wafer can be obtained.

[0061] (See Example 2 for reference) Prepare a coating composition containing a thermosetting resin component of polysiloxane resin and solvents of menthol and n-decane, with a viscosity of 2,500 mPa·s as measured by an E-type viscometer. The coating is formed by spin-coating the composition (1050 rpm, 20 seconds) onto the surface of a 12-inch silicon wafer. While the coated silicon wafer is rotated (700 rpm, 60 seconds), n-decane is continuously ejected from an injection nozzle in a rod shape and supplied to the outer periphery of the wafer surface and the outer periphery of the back side, thereby removing the coating on the outer periphery of the wafer surface and cleaning the outer periphery of the back side. Then, the coated silicon wafer is rotated (700 rpm, 60 seconds) and dried by rotation, and then heated at 120°C for 90 seconds to obtain a silicon wafer with a dried film. The silicon wafer with the drying film attached was heated at 200°C for 10 minutes to obtain a silicon wafer with a functional film attached.

[0062] (For comparison, refer to Example 1) The process of preparing the coating composition and spin coating (1050 rpm, 20 seconds) to form a coating film was carried out again in Reference Example 2 to obtain a silicon wafer with a coating film. Next, the coated silicon wafer is rotated to dry and then heated at 120°C for 90 seconds to obtain a silicon wafer with a dry film. The silicon wafer with the drying film attached was heated at 200°C for 10 minutes to obtain a silicon wafer with a functional film attached.

[0063] (Evaluation of the beveled portion (side) and back of the silicon wafer with functional film attached) Visually inspect the outer periphery (including the side surface) and back surface of each silicon wafer with functional film obtained in Reference Example 2 and Comparative Reference Example 1. In the silicon wafer with functional film in Comparative Reference Example 1, white precipitates were observed from the outer periphery to the side surface. These white precipitates are undesirable as they may contaminate the conveyor arm and heating plate of the apparatus during the drying film fabrication step. On the other hand, in the silicon wafer with the functional film in Reference Example 2, no white precipitates were found on the side or back of the wafer. Therefore, in order to manufacture a practically effective wafer with a functional film that is not contaminated by coating residue on the outer periphery and back side of the wafer and can prevent contamination of the device, a step of cleaning the outer periphery of the wafer surface (B-1) must be performed between the step of spin coating to form the coating (A) and the step of heating to form the dry film (C). Ideally, this step should be performed along with a step of cleaning the back side of the wafer (B-2).

[0064] (Refer to Example 3) Prepare a coating composition containing a thermosetting resin component of polysiloxane resin and a solvent of menthol and n-decane with a viscosity of 3,000 mPa·s as measured by an E-type viscometer. The coating is formed by spin-coating the composition (1050 rpm, 20 seconds) onto the surface of a 12-inch silicon wafer. While the coated silicon wafer is rotated (700 rpm, 60 seconds), n-decane is continuously sprayed and supplied to the outer periphery of the wafer surface and the outer periphery of the back side, thereby removing the coating on the outer periphery of the wafer surface and cleaning the outer periphery of the back side. Then, the coated silicon wafer is rotated (700 rpm, 60 seconds) and dried by rotation, and then heated at 120°C for 90 seconds to obtain a silicon wafer with a dried film. The dried film was peeled off from the silicon wafer with the film attached and placed into a 65 mm diameter metal cup. A 25 mm diameter metal plate was placed on top to prepare a test sample. The test sample was placed on an Anton Paar MCR302 dual-drive rheometer, and the viscosity of the dried film was measured at 25°C.

[0065] (Refer to Example 4) Prepare a coating composition containing a thermosetting resin component of polysiloxane resin and a solvent of menthol and n-decane with a viscosity of 3,000 mPa·s as measured by an E-type viscometer. The coating composition was placed in a 65 mm diameter metal cup, and a 25 mm diameter metal plate was placed on top to prepare a test sample. The test sample was placed on an Anton Paar MCR302 dual-drive rheometer, and the viscosity of the coating composition was measured at 25°C.

[0066] (Viscosity evaluation of dry film and coating composition) The viscosities of Reference Example 3 and Reference Example 4, measured using a rheometer at 25°C, are shown in Table 2 below. These results show that the viscosity can be significantly increased by performing the first heating step for making the dry film, thereby suppressing the flowability of the coating. In this way, by suppressing the flowability of the coating, the situation where a new film is supplied from the inside immediately after the film at the end is removed due to the centrifugal force of the wafer rotation will not occur. Therefore, by removing the end with a cleaning solution, the flowability suppression film on the outer periphery of the wafer surface can be cleanly removed, leaving a flowability suppression film with a good end face shape. Furthermore, considering the drying effect caused by spin coating, the flowability of the coating film is not the same as that of the coating composition. However, considering that the outer periphery of the silicon wafer with the functional film in Comparative Example 1 was not completely removed, and considering the results of Reference Example 2 and Comparative Reference Example 1, it can be considered that the flowability of the coating film is high enough to cover the side and back sides of the wafer; on the other hand, since the outer periphery of the silicon wafer with the functional film in Example 1 was completely removed, it can be considered that the flowability of the dried film is sufficiently suppressed; in addition, it is assumed that the increase in viscosity when forming the dried film by heating is more significant than the change in viscosity when obtaining the coating film from the coating composition. Based on this experiment, it can be confirmed that the flowability of the film can be sufficiently suppressed by the first heating step.

[0067] [Table 2]

[0068] As can be clearly seen from the above embodiments, the method for manufacturing a wafer with a functional film of the present invention can manufacture a wafer with a functional film as follows: the functional film on the outer periphery of the wafer surface is cleanly removed and the outer periphery of the wafer surface is exposed in a good annular shape. Furthermore, the beveled portion and back side of the wafer will not be contaminated by the coating residue and it is effective in practical use.

[0069] none

Claims

1. A method for manufacturing a wafer with a functional film applied to its outer periphery exposed in a ring shape, characterized by comprising the following steps: Step (A) of spin-coating a high-viscosity coating material containing components of a functional film that can be cured by heating onto the wafer surface; Step (B-1) of, while rotating the wafer, supplying a cleaning solution to the outer periphery of the wafer surface on which the coating film is formed, thereby removing the coating film from the outer periphery of the wafer surface; Step (C) of, after step (B-1) of heating the coating film on the wafer at a temperature lower than the temperature required for curing the components of the functional film. After step (C), while rotating the wafer, a cleaning solution is supplied to the outer periphery of the wafer surface on which the flow inhibition film is formed, thereby removing the flow inhibition film on the wafer surface (D-1); and after step (D-1), the flow inhibition film on the wafer is heated at a temperature greater than or equal to that required for the curing of the functional film components, thereby curing the functional film components and forming a functional film (E).

2. The method for manufacturing a wafer with a functional film as described in claim 1, wherein, The viscosity of this high-viscosity coating material is 1,000~15,000 mPa·s.

3. The method for manufacturing a wafer with a functional film as described in claim 1, wherein, The components of this functional membrane contain polymers.

4. The method for manufacturing a wafer with a functional film as described in claim 3, wherein, This polymer contains polysiloxane.

5. The method for manufacturing a wafer with a functional film as described in claim 1, wherein, In step (D-1) of removing the flow inhibition film on the wafer surface, while rotating the wafer, the following steps are performed: 1) supplying a cleaning solution to the outer periphery of the wafer surface on which the flow inhibition film is formed, thereby removing the flow inhibition film on the wafer surface (D-1-1); and 2) moving the supply position from the cleaning solution supply position in step (D-1-1) to a position outside the center of the wafer, and supplying cleaning solution to the outer periphery of the wafer surface on which the flow inhibition film is formed at the moved supply position, thereby removing the flow inhibition film on the wafer surface (D-1-2).

6. The method for manufacturing a wafer with a functional film as described in claim 1, wherein, The step (B-2) involves supplying a cleaning solution to the back side of the wafer after step (A) and before step (C) to clean the back side of the wafer.

7. The method for manufacturing a wafer with a functional film as described in claim 1, wherein, The step (D-2) involves supplying a cleaning solution to the back side of the wafer after step (C) and before step (E) to clean the back side of the wafer.

8. A method for manufacturing a wafer with a functional film as described in claim 1, wherein, This cleaning solution is a hydrocarbon-based cleaning solution.

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