Wafer edge protection film forming method, pattern forming method, and composition for forming wafer edge protection film

Abstract

To provide a wafer edge protection film which has better dry etching resistance than conventional wafer edge protection films, and has an excellent film forming property even at a wafer edge portion, which is difficult to coat.SOLUTION: A wafer edge protection film forming method is a method for forming a protection film on a peripheral edge of a substrate, and includes the steps of: coating the peripheral edge of the substrate with a protection film-forming composition comprising a solvent and an aromatic ring-containing resin (A) having an organic group represented by the general formula (1) in the figure; and curing the applied protection film-forming composition by heat or optical irradiation to form the protection film on the peripheral edge of the substrate. In the formula, RA is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms; and * represents a bonding site.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for forming a protective film on the peripheral edge of a substrate, and a pattern formation method using the protective film. [Background technology]

[0002] In the manufacturing process of a semiconductor device, for example, a resist pattern is formed on the substrate by sequentially performing a resist coating process in which a resist solution is applied onto a semiconductor substrate to form a resist upper layer film, an exposure process in which the resist film is exposed to light in a predetermined pattern, a development process in which the exposed resist upper layer film is developed, etc. Then, an etching process is performed using the resist pattern as a mask, and the predetermined pattern is formed on the substrate.

[0003] In such substrate processing, when etching the substrate to be processed using the resist top layer film pattern as a mask, if the substrate has an exposed peripheral edge (wafer edge), the exposed portion of the substrate is etched, generating particles, which can result in a decrease in the yield of semiconductor manufacturing.

[0004] Typically, the wafer edge is cut off and gradually slopes away from the substrate surface, as shown in Figure 1. The chamfered part of the wafer edge is called the bevel, and the vertical part is called the apex. Wafer edges with a shape like that shown in Figure 1(A) are called rounded, and those with a shape like that shown in Figure 1(B) are called bulleted.

[0005] To suppress particle generation from the wafer edge, a technique for forming a resist film only on the wafer edge is known. For example, as disclosed in Patent Document 1, a method for applying a photoresist liquid to the wafer edge while rotating the wafer is known.

[0006] Furthermore, in recent years, the formation of coating films using coating materials containing inorganic metals for resists and resist underlayer films has been considered. Since the deposition of metals on unintended portions of semiconductor substrates during the manufacturing process of semiconductor devices has a significant effect on the electrical characteristics of the semiconductor devices, strict control is being exercised to prevent such deposition of metals.

[0007] However, when forming a metal-containing coating film as described above, there is a concern that the chemical solution supplied to the substrate surface may flow around to the wafer edge and the peripheral edge of the backside, resulting in the formation of a coating film on these unintended areas, resulting in metal contamination of these areas. Furthermore, there is a concern that particles generated during etching of the metal-containing film may adhere to the wafer edge, resulting in metal contamination of these areas. Furthermore, if a contaminated portion of a substrate comes into contact with a substrate processing device such as an exposure device or an etching device or a substrate transport mechanism, substrates transported and processed thereafter via these processing devices or transport mechanisms may also be metal-contaminated, i.e., cross-contamination may occur. For this reason, methods for forming protective films to protect the wafer edge and the peripheral edge of the backside from metal-containing materials have been reported, as disclosed in Patent Documents 2 and 3.

[0008] As described above, the wafer edge protection film formation method is useful in fine patterning processes in semiconductor manufacturing processes, such as suppressing etching damage to the wafer edge and suppressing metal contamination of the wafer edge during processing of metal-containing materials.

[0009] Meanwhile, in recent semiconductor device manufacturing, the trend toward 3D device structures has led to an increase in processes for forming patterns with ultra-high aspect ratios on workpiece substrates. While negative photoresist solutions have generally been used for conventional wafer edge protection films, the etching process is becoming increasingly complex and time-consuming in the manufacture of cutting-edge devices, and it is anticipated that wafer edge protection films will require improved etching resistance. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-110386 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-045171 [Patent Document 3] Japanese Patent Application Publication No. 2018-124354 Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made in view of the above circumstances, and aims to provide a wafer edge protection film that has superior dry etching resistance compared to conventional wafer edge protection films and has excellent uniformity of application even on wafer edge portions that are difficult to coat. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention provides: A method for forming a protective film on a peripheral edge of a substrate, comprising: (i) coating the peripheral edge of the substrate with a protective film-forming composition containing an aromatic ring-containing resin (A) having an organic group represented by the following general formula (1) and a solvent; (ii) curing the coated protective film-forming composition by heat or light irradiation to form the protective film on the peripheral edge of the substrate; The present invention provides a method for forming a wafer edge protection film, comprising: [ka] (In the formula, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and * is a bonding site.

[0013] Such a wafer edge protection film formation method uses a wafer edge protection film formation material that contains an organic group of the above general formula (1), which has excellent reactivity and thermal fluidity, and a resin having an aromatic ring, which has excellent dry etching resistance. Therefore, it is possible to achieve excellent uniform application even on wafer edges that are difficult to cover, and it is also possible to protect the wafer edge even when forming a pattern with a high aspect ratio on the substrate to be processed.

[0014] Furthermore, it is preferable that the resin (A) further has hydroxyl groups, and the ratio of the number of the hydroxyl groups to the number of the organic groups represented by the general formula (1) satisfies the relationship a+b=1, 0.1≦b≦0.9, where a is the proportion of the hydroxyl groups and b is the proportion of the organic groups represented by the general formula (1).

[0015] Since the resin (A) contains both hydroxyl groups and organic groups of the general formula (1), it becomes a wafer edge protection film forming material that has both excellent thermal fluidity and substrate adhesion, and therefore a method for forming a wafer edge protection film that has excellent uniformity of application even on wafer edges that are difficult to cover can be provided. Furthermore, if the content of the organic group of the general formula (1) and hydroxyl groups is within the above range, it becomes possible to adjust various physical properties required when used to form a wafer edge protection film, such as defect suppression characteristics, dry etching resistance, and substrate adhesion, within appropriate ranges.

[0016] Furthermore, it is preferable that the resin (A) is an aromatic ring-containing resin having hydroxyl groups and organic groups represented by the following general formula (1A), and the ratio of the number of the hydroxyl groups to the number of the organic groups represented by the general formula (1A) satisfies the relationship c+d=1, 0.1≦d≦0.9, where c is the proportion of the hydroxyl groups and d is the proportion of the organic groups represented by the general formula (1A). [ka] (In the formula, * represents a binding site.)

[0017] The resin (A) containing both a hydroxyl group and an organic group of the general formula (1A) provides a wafer edge protection film forming material with excellent thermal fluidity and substrate adhesion, thereby providing a method for forming a wafer edge protection film with excellent uniformity. Furthermore, if the content of the organic group of the general formula (1A) and the hydroxyl group falls within the above range, it becomes possible to adjust, within appropriate ranges, the various physical properties required for use in forming a wafer edge protection film, such as defect suppression characteristics, dry etching resistance, and substrate adhesion.

[0018] Furthermore, the resin (A) is preferably a compound in which the ratio Mw / Mn (i.e., dispersity) of the weight average molecular weight Mw to the number average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography is within the range of 1.00≦Mw / Mn≦1.25.

[0019] A wafer edge protection film forming material containing a compound having a dispersity in this range has better thermal fluidity and can therefore exhibit excellent uniform coating properties.

[0020] The resin (A) is preferably a polymer having a weight average molecular weight of 1,000 to 12,000 in terms of polystyrene as determined by gel permeation chromatography.

[0021] A wafer edge protective film forming method using a wafer edge protective film forming material containing a polymer having a weight average molecular weight in this range can suppress outgassing during baking without impairing solubility in organic solvents.

[0022] Furthermore, the resin (A) preferably has at least one structural unit represented by the following general formulas (A-1), (A-2), (A-3), (A-4) and (A-5). [ka] (In the formula, W1 and W2 each independently represent a benzene ring or a naphthalene ring, and the hydrogen atoms in the benzene ring and the naphthalene ring may be substituted with a hydrocarbon group having 1 to 6 carbon atoms. R a is a hydrogen atom or an organic group represented by the following general formula (2), a In the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1 and 0.1≦f≦0.9 is satisfied. Y is a group represented by the following general formula (3): n1 is 0 or 1, n2 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety. [ka] (wherein Z1 is a group represented by the following general formula (4), and R a is a hydrogen atom or an organic group represented by the following general formula (2), a In the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1, 0.1≦f≦0.9 is satisfied. n4 is 0 or 1, n5 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety. [ka] (where * represents the bond site to the oxygen atom, R B is a divalent organic group having 1 to 10 carbon atoms, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. [ka] (* represents a bond.) [ka] (wherein W1, W2, Y, and n1 are the same as above.) [ka] (In the formula, m3 and m4 represent 1 or 2, and Z is a single bond or a structure represented by the following general formula (5). R x is any of the structures represented by the following general formula (6): [ka] (In the formula, * represents a bond, 1 represents an integer of 0 to 3, and R a ~R f each independently represents a hydrogen atom or an optionally fluorine-substituted alkyl group having 1 to 10 carbon atoms, a phenyl group, or a phenylethyl group; R a and R b may be bonded to form a cyclic compound.) [ka] (where * represents the bonding site to the aromatic ring, and Q1 is Carbon number It is a linear saturated hydrocarbon group having 1 to 30 carbon atoms, or a structure represented by the following general formula (7): [ka] (where * represents the bonding site to the carbonyl group, and R i is a hydrogen atom or an organic group represented by the general formula (2), and i In the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1 and 0.1≦f≦0.9 is satisfied. j represents a linear or branched hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, a nitro group, an amino group, a nitrile group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or an alkanoyloxy group having 1 to 10 carbon atoms. n3 and n4 represent the number of substituents on the aromatic ring, and each represents an integer of 0 to 7, provided that n3 + n4 is 0 or more and 7 or less. n5 represents 0 to 2. [ka] (In the formula, R 1is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, and R a is a hydrogen atom or an organic group represented by the general formula (2), and a In the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1 and 0.1≦f≦0.9 is satisfied. p is an integer of 0 to 5, q1 is an integer of 1 to 6, p+q1 is an integer of 1 or more and 6 or less, and q2 is 0 or 1.

[0023] Such a wafer edge protection film forming material contains a resin that has a high degree of both thermal fluidity and dry etching resistance, and therefore can exhibit excellent uniform application properties even on wafer edges that are difficult to coat.It can also protect the wafer edge when forming patterns with high aspect ratios on the substrate to be processed.

[0024] The content of the resin (A) in the composition for forming a protective film is preferably 10% by mass or more.

[0025] By using such a composition for forming an edge protection film, it is possible to form a thick edge protection film even on wafer edge portions that are difficult to coat, and it is possible to provide an edge protection film with a thickness sufficient to withstand the dry etching process of the substrate to be processed.

[0026] The protective film-forming composition preferably further contains one or more of a crosslinking agent, a high-boiling point solvent, a surfactant, an acid generator, and a plasticizer.

[0027] By using a composition for forming an edge protection film containing the above additives, it becomes possible to adjust various physical properties required when used to form a wafer edge protection film, such as defect suppression characteristics, dry etching resistance, and substrate adhesion, within appropriate ranges.

[0028] Furthermore, in step (i), it is preferable that the protective film is formed also on the peripheral edge of the back side of the substrate in addition to the peripheral edge of the front side of the substrate by coating the protective film forming composition on the peripheral edge of the back side of the substrate in step (ii).

[0029] By using the above-mentioned protective film-forming composition to form a protective film all the way to the peripheral edge of the back surface, it is possible to avoid the risk of metal contamination of these areas due to the chemical solution supplied to the surface of the substrate flowing around to the peripheral edge of the back surface when forming a metal-containing coating film, resulting in the coating film being formed on these unintended peripheral edges of the back surface.

[0030] It is also preferable that the coating in the step (i) is carried out by a spin coating method, and that the protective film is formed only on the peripheral edge of the front surface side and the peripheral edge of the back surface side of the substrate.

[0031] By applying the above-mentioned protective film-forming composition by a spin coating method and forming a protective film only on the peripheral edges on the front side and the back side, it is possible to significantly contribute to improving the productivity of the semiconductor manufacturing process, such as reducing the amount of chemicals consumed and shortening the manufacturing time.

[0032] In the step (ii), the coated protective film-forming composition is preferably cured by heat treatment at a temperature of 100° C. or higher and 800° C. or lower for 10 to 7,200 seconds.

[0033] By thermally curing, it is possible to form a dense cured film and improve dry etching resistance.

[0034] Further, the present invention provides a method for forming a pattern on a substrate to be processed by forming a protective film on a peripheral edge of the substrate to be processed on which a film having a pattern is formed, the method comprising the steps of: (I-1) a step of applying a protective film-forming composition containing an aromatic ring-containing resin (A) having an organic group represented by the following general formula (1) and a solvent to the peripheral edge of a substrate to be processed on which a patterned film has been formed; (I-2) a step of curing the applied protective film-forming composition by heat treatment or light irradiation to form a protective film on the peripheral edge of the substrate; (I-3) forming a pattern on the substrate to be processed by dry etching using the patterned film as a mask; (I-4) removing the protective film; The present invention provides a pattern forming method comprising the steps of: [ka] (In the formula, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and * is a bonding site.

[0035] The pattern forming method described above can suppress particle generation from the wafer edge when dry etching the substrate to be processed.

[0036] The present invention also provides a method for forming a protective film on a peripheral edge of a substrate to be processed and forming a pattern on the substrate to be processed, comprising the steps of: (II-1) a step of applying a protective film-forming composition to the peripheral edge of a substrate to be processed, the protective film-forming composition including an aromatic ring-containing resin (A) having an organic group represented by the following general formula (1) and a solvent; (II-2) A step of curing the applied protective film-forming composition by heat treatment or light irradiation to form a protective film on the peripheral edge of the substrate to be processed; (II-3) forming a resist upper layer film pattern on the substrate to be processed, and using the resist upper layer film pattern as a mask to form a pattern on the substrate to be processed by dry etching; (II-4) removing the protective film; The present invention provides a pattern forming method comprising the steps of: [ka] (In the formula, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and * is a bonding site.

[0037] The pattern formation method described above can suppress particle generation from the wafer edge when dry etching a substrate to be processed. Furthermore, when forming a resist top layer film, it is possible to avoid the risk of contamination of these areas due to the chemical solution supplied to the front surface of the substrate flowing around to the periphery of the back surface, resulting in the formation of a coating film on these unintended periphery of the back surface.

[0038] Furthermore, in step (I-1) or step (II-1), it is preferable to apply the protective film-forming composition to the peripheral edge of the back side of the substrate in addition to the peripheral edge of the front side of the substrate, so that in step (I-2) or step (II-2), the protective film is also formed on the peripheral edge of the back side of the substrate.

[0039] By using the above-mentioned protective film-forming composition to form a protective film all the way to the peripheral edge of the back surface, it is possible to avoid the risk of metal contamination of these areas due to the chemical solution supplied to the surface of the substrate flowing around to the peripheral edge of the back surface when forming a metal-containing coating film, resulting in the coating film being formed on these unintended peripheral edges of the back surface.

[0040] The present invention also provides a composition for forming a protective film for forming a protective film on a peripheral edge of a substrate, the composition comprising: The present invention provides a composition for forming a wafer edge protective film, which comprises an aromatic ring-containing resin (A) having an organic group represented by the following general formula (1) and a solvent. [ka] (In the formula, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and * is a bonding site.

[0041] Such a protective film-forming composition uses a wafer edge protective film-forming material containing an organic group of the above general formula (1), which has excellent reactivity and thermal fluidity, and a resin having an aromatic ring, which has excellent dry etching resistance. Therefore, it is possible to exhibit excellent uniform application properties even on wafer edges that are difficult to cover, and it is also possible to protect the wafer edge even when forming a pattern with a high aspect ratio on the substrate to be processed. [Effects of the Invention]

[0042] As described above, the wafer edge protection film formation method and pattern formation method of the present invention use a wafer edge protection film formation composition containing a resin with an aromatic ring-containing structure and a specific organic group structure that exhibits excellent thermal fluidity. This composition provides a wafer edge protection film that has superior dry etching resistance compared to conventional wafer edge protection films and exhibits excellent uniformity of application, even on wafer edges that are difficult to cover. In particular, even in dry etching processes for forming high-aspect-ratio fine patterns, such as those used in 3D-NAND memory, which are becoming increasingly highly stacked, this method can protect the wafer edge from etchants until the etching of the substrate is complete, thereby reducing particle generation from the wafer edge during etching. This makes the method extremely useful in fine patterning processes in semiconductor manufacturing. Furthermore, by forming a protective film on the peripheral edge of the backside, it is possible to prevent chemical solutions supplied to the front side of the substrate from flowing around to the peripheral edge of the backside when forming a metal-containing coating film, thereby avoiding the risk of metal contamination in these areas due to the formation of a coating film on these unintended peripheral edges of the backside. [Brief explanation of the drawings]

[0043] [Figure 1] FIG. 1 is an explanatory diagram of a wafer edge. [Figure 2] 1A to 1C are explanatory diagrams illustrating an example of a method for forming a wafer edge protection film according to the present invention (protecting only the wafer edge on the front surface side). [Figure 3] FIG. 10 is another explanatory view of the wafer edge. [Figure 4]10A and 10B are explanatory diagrams of another example of the method for forming a wafer edge protection film of the present invention (protecting only the wafer edge on the front side and the wafer edge on the back side). [Figure 5] 10 is an explanatory diagram of yet another example of the method for forming a wafer edge protection film of the present invention (protecting only the wafer edge on the front side and the wafer edge on the back side). FIG. [Figure 6] 1A to 1C are explanatory diagrams illustrating an example of a pattern formation method using the wafer edge protection film formation method of the present invention. [Figure 7] 10A to 10C are explanatory diagrams illustrating another example of a pattern forming method using the wafer edge protection film forming method of the present invention. [Figure 8] FIG. 10 is an explanatory diagram of film thickness evaluation points of a wafer edge protective film. [Figure 9] FIG. 10 is an explanatory diagram of a method for evaluating the amount of surface metal impurities at the peripheral edge of a wafer. DETAILED DESCRIPTION OF THE INVENTION

[0044] As mentioned above, wafer edge protection films are used in the fine patterning process of semiconductor manufacturing to prevent particles from being generated from the wafer edge during etching. However, in recent semiconductor device manufacturing, as device structures have become more 3D, there has been an increase in processes for forming patterns with ultra-high aspect ratios on the substrate being processed, and there has been a demand for wafer edge protection films that can withstand increasingly complex and long etching processes.

[0045] The present inventors have conducted extensive research into the above-mentioned problems and have sought to develop a method for forming a wafer edge protection film that is excellent in dry etching resistance and wafer edge coverage. As a result, they have found that a method for forming a wafer edge protection film using a composition for forming a wafer edge protection film that contains a resin with an aromatic ring-containing structure having an organic group with a specific structure that is excellent in thermal fluidity and crosslinking reactivity is very effective, and have completed the present invention.

[0046] That is, the present invention is a method for forming a protective film on the peripheral edge of a substrate, which includes the steps of: (i) coating the peripheral edge of the substrate with a protective film-forming composition containing an aromatic ring-containing resin (A) having an organic group represented by the following general formula (1) and a solvent; and (ii) curing the coated protective film-forming composition by heat or light irradiation to form the protective film on the peripheral edge of the substrate. [ka] (In the formula, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and * is a bonding site.

[0047] The present invention will be described in detail below, but the present invention is not limited thereto.

[0048] <Wafer edge protection film formation method> A protective film is formed on the peripheral edge of the substrate by applying a protective film-forming composition to the peripheral edge of the substrate.

[0049] Specifically, the method for forming a protective film on a peripheral edge of a substrate includes the steps of: (i) coating the peripheral edge of the substrate with a protective film-forming composition containing an aromatic ring-containing resin (A) having an organic group represented by general formula (1) described below and a solvent; (ii) curing the coated protective film-forming composition by heat or light irradiation to form the protective film on the peripheral edge of the substrate; The present invention provides a method for forming a wafer edge protection film, comprising:

[0050] By using this method for forming a wafer edge protection film, it is possible to form a wafer edge protection film with few defects that can withstand more complicated and longer etching processes.

[0051] The substrate is not particularly limited, and examples thereof include substrates such as Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, and Al, as well as substrates with a workpiece layer formed thereon. Examples of workpiece layers include low-k films and their stopper films, such as Si, SiO2, SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, and Al-Si, as well as Hf, Zr, Cr, Ge, Ag, Au, In, Ga, As, Pd, Fe, Ta, Co, Mn, Mo, Ru, and alloys thereof, amorphous carbon, organic resist underlayers, silicon-containing resist intermediate films, and hard masks, such as inorganic hard masks, and are typically formed to a thickness of 50 to 10,000 nm, and particularly 100 to 5,000 nm. When forming a workpiece layer, the substrate and workpiece layer are typically made of different materials.

[0052] As shown in Figure 3, the peripheral edge Wc of the substrate is preferably within 15 mm, more preferably within 10 mm, and particularly preferably within 5 mm, of the peripheral edge Wb of the substrate. In this specification, the peripheral edge (wafer edge) of the substrate refers to a location including the edge surface, bevel, and apex, as shown in Figure 1. The peripheral edge (wafer edge) of the substrate may also include the back surface of the edge, in which case it is referred to as the front-side peripheral edge and the back-side peripheral edge.

[0053] The method for forming a protective film using the composition for forming a wafer edge protective film of the present invention can form a protective film on the peripheral edge of the surface side of a substrate by applying the composition for forming a protective film to the peripheral edge of the surface side of a substrate.

[0054] As shown in FIG. 2(E), in step (i), a wafer (substrate) 1 is first placed on a rotatable spin chuck 2. The method for applying the protective film-forming composition to the substrate is not particularly limited, and suitable application methods can be used, such as a spin coating method (spin coating), in which a coating solution is continuously dispensed onto a substrate rotating at a constant speed, or a spray method, in which a coating solution is sprayed onto the substrate surface. In this embodiment, a spin coating method is used to apply the protective film-forming composition to the peripheral edge of the front surface of the wafer 1. Specifically, as shown in FIG. 2(F), the protective film-forming composition 4 is applied to the peripheral edge of the front surface of the wafer 1 while the spin chuck 2 is rotated at a rotation speed corresponding to the viscosity of the protective film-forming composition 4 and the desired coating thickness. The protective film-forming composition 4 is dispensed from the tip of a supply nozzle 3 for supplying the protective film-forming composition 4 from above onto the peripheral edge of the front surface of the wafer 1, which is rotating around a vertical axis in a horizontal plane. Then, in step (ii), a protective film 4A is formed on the peripheral edge of the front surface, as shown in FIG. 2(G).

[0055] The wafer edge protective film forming method of the present invention may be a method of forming a protective film on the peripheral edge (wafer edge) of a substrate on which a resist top layer film pattern has been formed, or a method of forming a wafer edge protective film on the substrate, then applying a resist top layer film and forming a resist top layer film pattern by exposure. Alternatively, it may be a method of forming a resist top layer film pattern using a multilayer resist method, typified by a three-layer resist process, in which a wafer edge protective film is formed on the substrate, then forming a resist underlayer film, an inorganic hard mask, etc., and then forming a resist top layer film on top of that. Since the substrate is processed using the patterned resist top layer film as a mask, it is preferable to form a protective film on the wafer edge using a wafer edge protective film forming composition before dry etching begins, as this can suppress particle generation from the wafer edge.

[0056] When the protective film is applied to the peripheral edge of the substrate, the protective film may be dried after application by rotating the spin chuck at, for example, 10 to 4000 rpm.

[0057] Furthermore, the wafer edge protective film forming method of the present invention can also form a protective film on the peripheral edge of the front surface side and the peripheral edge of the back surface side of the substrate by applying a protective film forming composition for forming the protective film to the peripheral edge of the front surface side and the peripheral edge of the back surface side of the substrate.

[0058] As shown in FIG. 4(I), in step (i), a wafer (substrate) 1 is first placed on a rotatable spin chuck 2. The method for applying the protective film-forming composition to the substrate is not particularly limited, and suitable application methods can be used, such as a spin coating method (spin coating), in which a coating solution is continuously dispensed onto a substrate rotating at a constant speed, or a spray method, in which a coating solution is sprayed onto the substrate surface. In this embodiment, a spin coating method is used to apply the protective film-forming composition to the peripheral edges of the front and back sides of the wafer 1. Specifically, as shown in FIG. 4(J), the protective film-forming composition 5 is applied to the peripheral edges of the front and back sides of the wafer 1 while the spin chuck 2 is rotated at a rotation speed corresponding to the viscosity of the protective film-forming composition 5 and the desired coating thickness. The protective film-forming composition 5 is dispensed from the tip of a supply nozzle 3 for supplying the protective film-forming composition 5 from above onto the peripheral edges of the front and back sides of the wafer 1, which is rotating around a vertical axis in a horizontal plane. In step (ii), a protective film 5A is formed on the peripheral edge of the front surface side and the peripheral edge of the back surface side as shown in FIG. 4(K).

[0059] In addition, when coating the peripheral edge of the front side and the peripheral edge of the back side of the substrate, the protective film-forming composition may be supplied from separate supply nozzles to the peripheral edge of the front side and the peripheral edge of the back side. For example, in the embodiment shown in FIG. 5, as shown in FIG. 5(L), the wafer 1 is placed on the spin chuck 2, and then, as shown in FIG. 5(M), the protective film-forming composition 6 is dispensed from the tips of the upper supply nozzle 3A and the lower supply nozzle 3B for supplying the protective film-forming composition 6 from above and below onto the peripheral edge of the front side and the peripheral edge of the back side of the rotating wafer 1, forming a protective film 6A on the peripheral edge of the front side and the peripheral edge of the back side as shown in FIG. 5(N). After coating, the protective film 6A may be dried by rotating the spin chuck 2 at, for example, 10 to 4,000 rpm.

[0060] The lower limit of the average thickness of the protective film is preferably 100 nm, more preferably 200 nm, for the surface portion; 100 nm, more preferably 200 nm, for the bevel portion; 200 nm, more preferably 300 nm, for the apex portion; and 1 nm, more preferably 5 nm, for the back portion.

[0061] The upper limit of the average thickness of the protective film is preferably 5,000 nm, more preferably 4,000 nm, for the surface portion; 5,000 nm, more preferably 4,000 nm, for the bevel portion; 7,000 nm, more preferably 6,000 nm, for the apex portion; and 1,000 nm, more preferably 500 nm, for the back portion.

[0062] The film thickness of the wafer edge protection film can be selected appropriately depending on the purpose of edge protection, but as long as it is within the above range, it is possible to provide a method for forming a wafer edge protection film that can withstand increasingly complex and long-lasting etching processes, such as those used in pattern formation processes with ultra-high aspect ratios.

[0063] The wafer edge protection film forming method of the present invention is preferably a method for forming a wafer edge protection film only on the peripheral edge of the front side and the peripheral edge of the back side of the substrate, which can contribute to the rationalization of the semiconductor manufacturing process by reducing the amount of chemical solution consumed for the wafer edge protection film forming composition and simplifying the protective film formation process and the protective film removal process.

[0064] In the method for forming a wafer edge protective film of the present invention, the composition for forming a wafer edge protective film applied to the peripheral edge of the front side and the peripheral edge of the back side of the substrate is cured by heat or light irradiation. In particular, a thermal curing method is more preferable from the viewpoint of dry etching resistance.

[0065] When the wafer edge protective film-forming composition applied to the peripheral edge of the front side and the peripheral edge of the back side of the substrate is thermally cured, the protective film is preferably formed by heat-treating the protective film-forming composition at a temperature of 100° C. to 800° C., preferably 150° C. to 600° C., for 10 to 7,200 seconds, preferably 10 to 600 seconds. From the viewpoint of reducing sublimates of the wafer edge protective film-forming composition, a temperature of 100° C. to 450° C. is more preferable, and from the viewpoint of productivity, heat treatment for 10 to 300 seconds is more preferable.

[0066] A temperature within the above range is preferable because it allows the formation of a wafer edge protection film with excellent dry etching resistance, and also because when a coating material such as photoresist is applied to the substrate to be processed on which the wafer edge protection film has been formed, problems such as mixing of the wafer edge protection film with the resist film and peeling of the protection film due to an edge cut rinse such as PGMEA do not occur.

[0067] When the composition for forming a wafer edge protective film applied to the peripheral edge of the front side and the peripheral edge of the back side of the substrate is cured by light irradiation, the light used for curing is not particularly limited, and examples thereof include light or radiation with wavelengths in the range of high-energy ionizing radiation, near ultraviolet, far ultraviolet, visible light, infrared, etc. Suitable examples of radiation that can be used include microwaves, EUV, LED, semiconductor laser light, and laser light used in the microfabrication of optical semiconductors, such as 248 nm KrF excimer laser light or 193 nm ArF excimer laser light.

[0068] These lights may be monochrome lights or lights of multiple different wavelengths (mixed lights). The wavelength of the light may be, for example, about 150 to 800 nm, preferably about 150 to 600 nm, and more preferably about 150 to 400 nm. The amount of light irradiated (irradiation energy) is not particularly limited and may be, for example, about 1 to 10,000 mW, preferably about 5 to 5,000 mW, and more preferably about 10 to 1,000 mW. The irradiation time is also not particularly limited and may be, for example, about 5 seconds to 60 minutes, preferably about 10 seconds to 30 minutes, and more preferably about 30 seconds to 10 minutes.

[0069] The heat treatment and the light irradiation may be combined.

[0070] It is more difficult to form a uniform film when coating the wafer edge than when coating the wafer surface, and therefore excellent film-forming properties are required of the composition for forming a wafer edge protective film. On the other hand, the method for forming a wafer edge protective film of the present invention uses an aromatic ring-containing resin (A) containing an organic group represented by the above general formula (1) to protect the peripheral edge of the substrate to be processed, so that roughness of the film that occurs during coating can be repaired by thermal flow, and a method for forming a wafer edge protective film with excellent uniformity of application can be provided.

[0071] <Composition for forming wafer edge protective film> The composition for forming a wafer edge protective film of the present invention contains an aromatic ring-containing resin (A) having an organic group represented by the following general formula (1) and a solvent. [ka] (In the formula, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and * is a bonding site.

[0072] [(A) Resin] The resin (A) has an organic group represented by the general formula (1), which improves thermal fluidity and enables excellent uniform application even at wafer edges that are difficult to coat. Furthermore, the resin (A) contains an aromatic ring, which provides excellent dry etching resistance and protects the wafer edge even when a pattern with a high aspect ratio is formed on the substrate.

[0073] In the above general formula (1), R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and is preferably a hydrogen atom or a group represented by the following formula (R a The structure shown in formula (1) is preferred.

[0074] [ka] (In the formula, * represents a bond, and p is 1 to 9, preferably 1 to 6.)

[0075] The resin (A) preferably further has hydroxyl groups, and the ratio of the number of the hydroxyl groups to the number of the organic groups represented by the general formula (1) satisfies the relationship a+b=1, 0.1≦b≦0.9, where a is the proportion of the hydroxyl groups and b is the proportion of the organic groups represented by the general formula (1), more preferably 0.2≦b≦0.8, and even more preferably 0.3≦b≦0.7.

[0076] By controlling the salicylic acid group and the organic group represented by the above general formula (1) within the above range, it is possible to highly exhibit thermal fluidity and substrate adhesion, and a composition for forming a wafer edge protection film excellent in the coating property and defect suppression property of the wafer edge can be provided. When it is desired to improve the adhesion of the film to the substrate, the ratio a of the hydroxyl group may be increased, that is, a > b. When it is desired to improve the curability, heat resistance, and defect suppression property, a < b may be set. These can be adjusted to any ratio according to the required performance.

[0077] It is preferable that the resin (A) is an aromatic ring-containing resin having a hydroxyl group and an organic group represented by the following general formula (1A).

Chemical formula

[0078] By having the organic group represented by the above general formula (1A), the thermal fluidity can be further improved, and excellent uniform coating property can be exhibited even in the wafer edge part where coating is difficult. Further, by containing an oxygen atom, the solubility in an organic solvent can be improved.

[0079] When the ratio of the number of the hydroxyl group and the organic group represented by the above general formula (1A) contained in the resin (A) is such that the ratio of the hydroxyl group is c and the ratio of the organic group represented by the above general formula (1A) is d, it is preferably satisfied that c + d = 1 and 0.1 ≤ d ≤ 0.9, more preferably 0.2 ≤ d ≤ 0.8, and even more preferably 0.3 ≤ d ≤ 0.7.

[0080] By controlling the hydroxyl group and the above general formula (1A) within the above ranges, it is possible to highly exhibit thermal fluidity and substrate adhesion, and a composition for forming a wafer edge protection film excellent in the coverage of the wafer edge and defect suppression can be provided. When it is desired to improve the adhesion of the film to the substrate, the ratio c of the hydroxyl group may be increased, that is, c > d. When it is desired to improve the curability, heat resistance, and defect suppression, c < d may be set. These can be adjusted to any ratio according to the required performance.

[0081] It is preferable that the resin (A) has a ratio Mw / Mn (that is, dispersity) of the weight average molecular weight Mw and the number average molecular weight Mn in terms of polystyrene by gel permeation chromatography within the range of 1.00 ≦ Mw / Mn ≦ 1.25, and more preferably 1.00 ≦ Mw / Mn ≦ 1.10. By definition, for a monomolecular compound, Mw / Mn is 1.00, but due to the separation property of GPC, the measured value may exceed 1.00. Generally, for a polymer having repeating units, it is extremely difficult to approach Mw / Mn = 1.00 unless a special polymerization method is used, and it has a distribution of Mw and Mw / Mn becomes a value exceeding 1. In the present invention, 1.00 ≦ Mw / Mn ≦ 1.10 is defined as an index indicating monomolecularity to distinguish between monomolecular compounds and polymers.

[0082] For a compound having a dispersity within such a range, the thermal fluidity of the composition for forming a wafer edge protection film becomes better, so that when blended with a material, a composition for forming a wafer edge protection film having better coverage of the wafer edge and defect suppression can be provided.

[0083] It is preferable that the resin (A) is a polymer having a weight average molecular weight in terms of polystyrene by gel permeation chromatography of 1,000 to 12,000, and more preferably Mw is 2,000 to 10,000.

[0084] Within this molecular weight range, solubility in organic solvents can be ensured, sublimation during baking can be suppressed, and the thermal fluidity of the wafer edge protection film composition can be improved, so that when blended with a material, a wafer edge protection film composition with superior wafer edge coverage and defect suppression can be provided.

[0085] The resin (A) preferably has at least one structural unit represented by the following general formulas (A-1), (A-2), (A-3), (A-4) and (A-5).

[0086] (Constituent units: A-1, A-2 and A-3) [ka] (In the formula, W1 and W2 each independently represent a benzene ring or a naphthalene ring, and the hydrogen atoms in the benzene ring and the naphthalene ring may be substituted with a hydrocarbon group having 1 to 6 carbon atoms. R a is a hydrogen atom or an organic group represented by the following general formula (2), a In the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1 and 0.1≦f≦0.9 is satisfied. Y is a group represented by the following general formula (3): n1 is 0 or 1, n2 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety. [ka] (wherein Z1 is a group represented by the following general formula (4), and R a is a hydrogen atom or an organic group represented by the following general formula (2), a In the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1, 0.1≦f≦0.9 is satisfied. n4 is 0 or 1, n5 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety. [ka] (where * represents the bond site to the oxygen atom, R B is a divalent organic group having 1 to 10 carbon atoms, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. [ka] (* represents a bond.) [ka] (wherein W1, W2, Y, and n1 are the same as above.)

[0087] Resins having structural units represented by the above general formulas (A-1), (A-2), and (A-3) incorporate high-carbon-density fused carbon rings containing a cardo structure, making it possible to form a wafer edge protection film with excellent dry etching resistance and heat resistance. Because of these characteristics, it is possible to protect the wafer edge from the dry etching process by forming a thinner protection film, which is preferable from the viewpoints of productivity and production cost of the composition for forming a wafer edge protection film.

[0088] In the above general formulae (A-1), (A-2) and (A-3), the above R a is a hydrogen atom or an organic group represented by the above general formula (2), and the above general formula (2) preferably has a structure represented by the following general formula (2-A). [ka] (* indicates the bond to the oxygen atom.)

[0089] When the general formulas (A-1), (A-2), and (A-3) contain an organic group represented by the general formula (2), particularly an organic group represented by the general formula (2-A), the thermal fluidity can be further improved, and excellent uniform coating properties can be achieved that can suppress defects such as liquid columns and craters, even in the wafer apex area, which is difficult to coat.

[0090] When the ratio of the number of hydroxyl groups contained in the above general formulas (A-1), (A-2) and (A-3) to the organic group represented by the above general formula (2) is such that the proportion of hydroxyl groups is e and the proportion of the organic group represented by the general formula (2) is f, it is preferably satisfied that e + f = 1 and 0.1 ≦ f ≦ 0.9, more preferably the relationship of 0.2 ≦ f ≦ 0.8, and even more preferably the relationship of 0.3 ≦ f ≦ 0.7.

[0091] By controlling the hydroxyl group and the above general formula (2) within the above range, it is possible to highly exhibit thermal fluidity and substrate adhesion, and a wafer edge protective film forming composition excellent in the coating property and defect suppressing property of the wafer edge can be provided. When it is desired to improve the adhesion of the film to the substrate, the proportion e of the hydroxyl group may be increased, that is, e > f. When it is desired to improve the curability, heat resistance, and defect suppressing property, e < f may be set. These can be adjusted to an arbitrary ratio according to the required performance.

[0092] The resin having the structural units represented by the above general formulas (A-1), (A-2) and (A-3) relaxes the intermolecular interaction and imparts solubility in an organic solvent due to the action of the kardo structure introduced into the molecule, thereby improving the film-forming property during the formation of the coating film. In addition, since a plurality of condensed carbon rings with a high carbon density are introduced, it is possible to form a wafer edge protective film excellent in heat resistance characteristics and dry etching resistance.

[0093] The resin having the structural units represented by the above general formulas (A-1), (A-2) and (A-3) can be a compound represented by the following general formula (a-1) and / or (a-2) and / or (a-3).

[0094] <000​​​​​​​​​​​​​, Y, n1, and n2 are as explained above in relation to general formulae (A-1) and (A-2).

[0096] [ka] (In the above general formula (a-3), Z1, R a , n4, and n5 are the same as above.)

[0097] In the above general formula (a-3), Z1 and R a , n4, and n5 are as explained above in relation to general formula (A-3).

[0098] Specific examples of resins having structural units represented by the above general formulae (a-1), (a-2) and (a-3) include, but are not limited to, the following compounds.

[0099] [ka]

[0100] The resins (a-1), (a-2), and (a-3) preferably have a ratio Mw / Mn (i.e., dispersity) of the weight average molecular weight Mw to the number average molecular weight Mn, as calculated on a polystyrene basis by gel permeation chromatography, within the range of 1.00≦Mw / Mn≦1.25, and more preferably 1.00≦Mw / Mn≦1.10.

[0101] A compound having a dispersity within this range will further improve the thermal fluidity of the composition for forming a wafer edge protective film, and when blended into a material, it will be possible to provide a composition for forming a wafer edge protective film that has excellent wafer edge coverage and defect suppression properties.

[0102] The resin having the structural units represented by the above general formulae (A-1), (A-2), and (A-3) can be a polymer having repeating units represented by the following general formulae (a-4) and / or (a-5) and / or (a-6).

[0103] [ka] (In the above general formulas (a-4) and (a-5), W1, W2, R a Y, n1, and n2 are the same as above, and L is a divalent organic group having 1 to 40 carbon atoms.

[0104] In the above general formulae (a-4) and (a-5), W1, W2, R a , Y, n1, and n2 are as explained above in relation to general formulae (A-1) and (A-2).

[0105] [ka] (In the above general formula (a-6), Z1, R a n4 and n5 are the same as above, and L is a divalent organic group having 1 to 40 carbon atoms.

[0106] In the general formula (a-6), Z1 and R a , n4, and n5 are as explained above in relation to general formula (A-3).

[0107] These polymers are obtained using the compounds represented by the general formulas (a-1), (a-2), and (a-3), and because they use the compounds, they have excellent dry etching resistance and heat resistance. In addition, because they are polymers having repeating units rather than monomers, they have low outgassing components, and because they are polymers having a molecular weight distribution, crystallinity is alleviated, and improved film formability can be expected.

[0108] L, which is a linking group constituting the repeating units of the above general formulae (a-4), (a-5) and (a-6), is a divalent organic group having 1 to 40 carbon atoms, and specific examples include the following.

[0109] [ka]

[0110] Furthermore, the linking group L of the above-described polymer is preferably the following general formula (10). [ka] (In the above general formula (10), R1 is a hydrogen atom or an organic group containing an aromatic ring having 1 to 20 carbon atoms, and the dashed line represents a bond.)

[0111] Specific examples of the general formula (10) are as follows, and among the following, a methylene group, that is, a compound in which R1 is a hydrogen atom, is preferred in view of the ease of obtaining raw materials.

[0112] [ka]

[0113] Furthermore, the weight average molecular weight of the polymer having repeating structural units represented by the above general formulae (a-4), (a-5), and (a-6) in terms of polystyrene, as determined by gel permeation chromatography, is preferably 1,000 to 12,000, and more preferably Mw is 2,000 to 10,000.

[0114] Within this molecular weight range, solubility in organic solvents can be ensured, sublimation during baking can be suppressed, and the thermal fluidity of the wafer edge protection film composition can be improved, so that when blended with a material, a wafer edge protection film composition with superior wafer edge coverage and defect suppression can be provided.

[0115] Resins containing structural units represented by the general formulas (A-1), (A-2), and (A-3) have a cardo-containing skeletal structure, resulting in high carbon density. Therefore, compositions for forming wafer edge protective films containing these compounds exhibit extremely high dry etching resistance and excellent heat resistance. Furthermore, because they contain an organic group represented by the general formula (2), which contributes to improved thermal fluidity, they can provide compositions for forming wafer edge protective films with excellent wafer edge coverage and defect suppression. Compounds with structures represented by the general formulas (a-1), (a-2), and (a-3) further improve the thermal fluidity of wafer edge protective film compositions. When incorporated into materials, these compositions can provide wafer edge protective film compositions with excellent wafer edge coverage and defect suppression. Meanwhile, polymers containing structural units represented by the general formulas (a-4), (a-5), and (a-6) can suppress the generation of sublimates during baking, enabling the provision of wafer edge protective films with excellent film thickness uniformity. By mixing compounds having structures represented by the above general formulae (a-1), (a-2), and (a-3) with polymers containing structural units represented by the above general formulae (a-4), (a-5), and (a-6), it is possible to provide a wafer edge protective film-forming composition that meets the required characteristics. As described above, a wafer edge protective film-forming composition using a resin containing structural units represented by the above general formulae (A-1), (A-2), and (A-3) can achieve both film-forming properties and heat resistance / etching resistance at an extremely high level.

[0116] (Composition unit: A-4) [ka] (In the formula, m3 and m4 represent 1 or 2, and Z is a single bond or a structure represented by the following general formula (5). R x is any of the structures represented by the following general formula (6): [ka] (In the formula, * represents a bond, 1 represents an integer of 0 to 3, and R a ~Rf each independently represents a hydrogen atom or an optionally fluorine-substituted alkyl group having 1 to 10 carbon atoms, a phenyl group, or a phenylethyl group; R a and R b may be bonded to form a cyclic compound.) [ka] (where * represents the bonding site to the aromatic ring, and Q1 is Carbon number It is a linear saturated hydrocarbon group having 1 to 30 carbon atoms, or a structure represented by the following general formula (7): [ka] (where * represents the bonding site to the carbonyl group, and R i is a hydrogen atom or an organic group represented by the general formula (2), and i In the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1 and 0.1≦f≦0.9 is satisfied. j represents a linear or branched hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, a nitro group, an amino group, a nitrile group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or an alkanoyloxy group having 1 to 10 carbon atoms. n3 and n4 represent the number of substituents on the aromatic ring, and each represents an integer of 0 to 7, provided that n3 + n4 is 0 or more and 7 or less. n5 represents 0 to 2.

[0117] From the viewpoint of dry etching resistance and heat resistance, in the above general formula (A-4), Z is preferably either a single bond or a structure represented by the following formula (4A). [ka] (In the formula, * represents a bond, and l is the same as in formula (5) above.)

[0118] In the above general formula (6), * represents the bonding site to the aromatic ring, Q1 is a linear saturated hydrocarbon group having 1 to 30 carbon atoms, or a structure represented by the above general formula (7). When Q1 represents a linear hydrocarbon group having 1 to 30 carbon atoms, the methylene group constituting Q1 may be substituted with an oxygen atom or a carbonyl group. From the viewpoints of dry etching resistance and heat resistance, Q1 preferably has a structure represented by the above general formula (7).

[0119] When the above general formula (A-4) has an organic group represented by the above general formula (2), particularly an organic group represented by the above general formula (2-A), the thermal fluidity can be further improved, and excellent uniform coating properties can be exhibited even in a wafer edge portion where coating is difficult.

[0120] When the ratio of the number of hydroxyl groups contained in the above general formula (A-4) to the organic group represented by the above general formula (2) is such that the proportion of hydroxyl groups is e and the proportion of the organic group represented by the above general formula (2) is f, it preferably satisfies the relationship of e + f = 1, 0.1 ≤ f ≤ 0.9, more preferably the relationship of 0.2 ≤ f ≤ 0.8, and even more preferably the relationship of 0.3 ≤ f ≤ 0.7.

[0121] By controlling the hydroxyl group and the above general formula (2) within the above ranges, it is possible to highly exhibit thermal fluidity and substrate adhesion, and a composition for forming a wafer edge protective film excellent in wafer edge coating properties and defect suppression properties can be provided. When it is desired to improve the adhesion of the film to the substrate, the proportion e of the hydroxyl group may be increased, that is, e > f. When it is desired to improve the curability, heat resistance, and defect suppression properties, e < f may be set. These can be adjusted to an arbitrary ratio according to the required performance.

[0122] Compounds containing the structural unit represented by the general formula (A-4) have a structure in which aromatic rings are linked by a single bond or general formula (5), and therefore have a high carbon density. Therefore, compositions for forming wafer edge protective films containing these compounds exhibit high dry etching resistance and excellent heat resistance. Furthermore, as shown in the general formula (5), the linking group Z can be appropriately selected from various linking groups to suit the desired performance. In particular, by introducing the structure represented by the general formula (4A) as Z, heat resistance / etching resistance can be imparted without impairing film formability. Furthermore, the highly flexible terminal portion R x Therefore, even though the compound contains a rigid aromatic ring structure, it is possible to form a thick protective film on the wafer edge without generating defects such as cracks. x contains a terminal group Q1 that imparts thermal fluidity, and as the terminal group Q1, a flexible hydrocarbon structure that contributes to improving thermal fluidity and a rigid aromatic ring structure that contributes to etching resistance and heat resistance can be introduced in any ratio according to the required performance. As described above, a composition for forming a wafer edge protective film using these compounds can achieve both high levels of film-forming ability and heat resistance / etching resistance, and can form a thick film according to the required properties.

[0123] (Composition unit: A-5) [ka] (In the formula, R 1 is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, and R a is a hydrogen atom or an organic group represented by the general formula (2), and a In the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1 and 0.1≦f≦0.9 is satisfied. p is an integer of 0 to 5, q1 is an integer of 1 to 6, p+q1 is an integer of 1 or more and 6 or less, and q2 is 0 or 1.

[0124] In the general formula (A-5), examples of the divalent organic group having 1 to 30 carbon atoms represented by X include alkanediyl groups such as methylene, ethanediyl, propanediyl, butanediyl, pentanediyl, hexanediyl, octanediyl, and decanediyl groups; monocyclic cycloalkanediyl groups such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, cyclooctanediyl, cyclodecanediyl, methylcyclohexanediyl, and ethylcyclohexanediyl groups; bicyclo[2.2.1]heptanediyl, bicyclo[2.2.2]octanediyl, and tricyclo[5.2.1.0]octanediyl groups; 2,6 ]decanediyl group (dicyclopentylene group), tricyclo[3.3.1.1 3,7 ]decanediyl group, tetracyclo[6.2.1.1 3,6 .0 2,7 ] Polycyclic cycloalkanediyl groups such as dodecanediyl group and adamantanediyl group, and arenediyl groups such as phenylene group and naphthylene group.

[0125] Examples of the alkanediyloxy group represented by X include groups formed by combining the above alkanediyl group with an oxygen atom, and examples of the cycloalkanediyloxy group represented by X include groups formed by combining the above cycloalkanediyl group with an oxygen atom.

[0126] Some or all of the hydrogen atoms of the alkanediyl group, cycloalkanediyl group, alkanediyloxy group, cycloalkanediyloxy group, arenediyl group, etc. may be substituted, and examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom, hydroxyl group, cyano group, carboxy group, nitro group, amino group, alkoxy group, alkoxycarbonyl group, acyl group, alkoxycarbonyloxy group, aryl group, and aliphatic heterocyclic groups such as lactone group, and aromatic heterocyclic groups such as furyl group and pyridyl group.

[0127] Examples of the organic group represented by X include groups represented by the following formulas. [Chemical formula] (In the above formula, * represents a bond.)

[0128] From the perspective of raw material availability, X is preferably a methylene group.

[0129] Specific examples of the resin having the structural unit represented by the general formula (A-5) include the following.

[0130] [Chemical formula]

[0131] [Chemical formula]

[0132] When the ratio of the number of hydroxyl groups contained in the general formula (A-5) to the organic group represented by the general formula (2) is such that the proportion of hydroxyl groups is e and the proportion of the organic group represented by the general formula (2) is f, it is preferable to satisfy the relationship of e + f = 1, 0.1 ≤ f ≤ 0.9. The relationship of 0.2 ≤ f ≤ 0.8 is more preferable, and the relationship of 0.

[0133] By controlling the hydroxyl group and the general formula (2) within the above ranges, it is possible to highly exhibit thermal fluidity and substrate adhesion, and a composition for forming a wafer edge protection film excellent in coating property and defect suppression property of the wafer edge can be provided. When it is desired to improve the adhesion of the film to the substrate, the proportion e of the hydroxyl group can be increased, that is, e > f. When it is desired to improve the curability, heat resistance, and defect suppression property, e < f can be set. These can be adjusted to any ratio according to the required performance.

[0134] <End of text> Polymers containing structural units represented by the general formula (A-5) have a structure in which aromatic rings are linked by organic groups (X), resulting in high carbon density. Therefore, compositions for forming wafer edge protective films containing these compounds exhibit high dry etching resistance and excellent heat resistance, allowing for the formation of protective films with minimal sublimation. Furthermore, because the organic group represented by the general formula (2), which contributes to improved thermal fluidity, is directly bonded to the aromatic ring, which is the resin's core structure, via an oxygen atom, compositions for forming wafer edge protective films using these polymers can achieve high levels of both film-forming properties and heat resistance / etching resistance. Furthermore, because the aromatic ring structure of the core is not too rigid and forms a repeating structure via the organic group (X), which is the linking group, thick protective films can be formed on wafer edges without generating defects such as cracks. As described above, compositions for forming wafer edge protective films using these polymers can achieve high levels of both film-forming properties and heat resistance / etching resistance, allowing for the formation of thick films tailored to desired properties.

[0135] The composition for forming a wafer edge protective film of the present invention preferably contains 10% by mass or more of the resin (A), more preferably 15% by mass or more, and even more preferably 20% by mass or more.

[0136] Even in a dry etching process for forming a fine pattern having an ultra-high aspect ratio on a workpiece substrate, a thick wafer edge protection film must be formed to protect the wafer edge from the etchant until the etching of the workpiece substrate is completed. The composition for forming a wafer edge protection film containing the resin (A) in the above-mentioned content makes it possible to form a thick wafer edge protection film that meets the required characteristics.

[0137] [(B) Solvent] The solvent (organic solvent) that can be used in the composition for forming the wafer edge protective film is not particularly limited as long as it can dissolve the resin (A), and it is preferable that it can also dissolve the crosslinking agent, surfactant, acid generator, and plasticizer described below.

[0138] Specifically, the solvents described in paragraphs

[0091] and

[0092] of JP 2007-199653 A can be added. More specifically, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, 2-heptanone, cyclopentanone, cyclohexanone, γ-butyrolactone, or a mixture containing one or more of these is preferably used.

[0139] The amount of organic solvent added is desirably adjusted depending on the set film thickness of the wafer edge protection film, but is usually in the range of 100 to 50,000 parts by mass per 100 parts by mass of the resin (A).

[0140] [(C) Crosslinking agent] A crosslinking agent can also be added to the wafer edge protective film-forming composition to enhance curability and dry etching resistance. The crosslinking agent is not particularly limited, and a wide variety of known crosslinking agents can be used. Examples include melamine-based crosslinking agents, glycoluril-based crosslinking agents, benzoguanamine-based crosslinking agents, urea-based crosslinking agents, β-hydroxyalkylamide-based crosslinking agents, isocyanurate-based crosslinking agents, aziridine-based crosslinking agents, oxazoline-based crosslinking agents, epoxy-based crosslinking agents, and phenol-based crosslinking agents (e.g., methylol or alkoxymethyl-type crosslinking agents of polynuclear phenols). When a crosslinking agent is added, the amount added is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass, per 100 parts by mass of the resin (A).

[0141] Specific examples of melamine-based crosslinking agents include hexamethoxymethylated melamine, hexabutoxymethylated melamine, alkoxy- and / or hydroxy-substituted derivatives thereof, and partial self-condensates thereof. Specific examples of glycoluril-based crosslinking agents include tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril, alkoxy- and / or hydroxy-substituted derivatives thereof, and partial self-condensates thereof. Specific examples of benzoguanamine-based crosslinking agents include tetramethoxymethylated benzoguanamine, tetrabutoxymethylated benzoguanamine, alkoxy- and / or hydroxy-substituted derivatives thereof, and partial self-condensates thereof. Specific examples of urea-based crosslinking agents include dimethoxymethylated dimethoxyethyleneurea, alkoxy- and / or hydroxy-substituted derivatives thereof, and partial self-condensates thereof. Specific examples of β-hydroxyalkylamide-based crosslinking agents include N,N,N',N'-tetra(2-hydroxyethyl)adipamide. Specific examples of isocyanurate crosslinking agents include triglycidyl isocyanurate and triallyl isocyanurate.Specific examples of aziridine crosslinking agents include 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane and 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate]. Specific examples of the oxazoline-based crosslinking agent include 2,2'-isopropylidenebis(4-benzyl-2-oxazoline), 2,2'-isopropylidenebis(4-phenyl-2-oxazoline), 2,2'-isopropylidenebis(4-phenyl-2-oxazoline), 2,2'-methylenebis-4,5-diphenyl-2-oxazoline, 2,2'-methylenebis-4-phenyl-2-oxazoline, 2,2'-methylenebis-4-tertbutyl-2-oxazoline, 2,2'-bis(2-oxazoline), 1,3-phenylenebis(2-oxazoline), 1,4-phenylenebis(2-oxazoline), and 2-isopropenyloxazoline copolymer.Specific examples of epoxy-based crosslinking agents include diglycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, poly(glycidyl methacrylate), trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol tetraglycidyl ether.

[0142] Specific examples of polynuclear phenol-based crosslinking agents include compounds represented by the following general formula (C-2).

[0143] [ka] (In the formula, Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. R3 is a hydrogen atom or a methyl group. q is an integer of 1 to 5.)

[0144] In the general formula (C-2) above, Q is a single bond or a q-valent hydrocarbon group having 1 to 20 carbon atoms. q is an integer of 1 to 5, and more preferably 2 or 3. When Q is a q-valent hydrocarbon group having 1 to 20 carbon atoms, Q is a q-valent hydrocarbon group obtained by removing q hydrogen atoms from a hydrocarbon having 1 to 20 carbon atoms. More specific examples of the hydrocarbon having 1 to 20 carbon atoms in this case include methane, ethane, propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, methylpentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, benzene, toluene, xylene, ethylbenzene, ethylisopropylbenzene, diisopropylbenzene, methylnaphthalene, ethylnaphthalene, and eicosane.

[0145] R3 in the above general formula (C-2) is a hydrogen atom or a methyl group, and is preferably a methyl group.

[0146] The inclusion of the compound represented by the general formula (C-2) as a crosslinking agent increases the crosslinking reactivity of the hydroxyl groups contained in the resin (A), thereby improving the density of the film, and thereby further improving the heat resistance of the composition for forming a wafer edge protective film.

[0147] Specific examples of the compound represented by the general formula (C-2) above include, but are not limited to, the following compounds. In the formula below, R3 is the same as above. From the viewpoints of curability, improved film thickness uniformity, and reduced sublimate, it is preferable that q = 3 and R3 = methyl group, and particularly preferred are hexamethoxymethylated triphenolmethane, triphenolethane, 1,1,1-tris(4-hydroxyphenyl)ethane, and tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene.

[0148] [ka]

[0149] [ka]

[0150] The crosslinking agent can be used alone or in combination of two or more. The content of the crosslinking agent is preferably 5% to 100% by mass, more preferably 10% to 50% by mass, relative to 100% by mass of the resin (A). When the amount added is 5% by mass or more, the crosslinking reaction with the resin (A) is promoted, and a dense film with excellent curing properties is formed, making it possible to form a wafer edge protection film with good heat resistance, dry etching resistance, and film thickness uniformity. On the other hand, when the amount added is 100% by mass or less, the generation of sublimates due to slowing of the crosslinking reaction between the resin (A) and the crosslinking agent (C) can be suppressed, and the generation of sublimates and deterioration of film thickness uniformity can be reduced.

[0151] [(D) High boiling point solvent] In addition, a high-boiling point solvent may be added to the composition for forming a wafer edge protective film in addition to the solvent (B). In this case, the organic solvent contained in the composition may be a mixture of one or more organic solvents having a boiling point of less than 180°C and one or more organic solvents having a boiling point of 180°C or higher (hereinafter referred to as "(D) high-boiling point solvent").

[0152] Specific examples of organic solvents having a boiling point of less than 180°C include propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, 2-heptanone, cyclopentanone, and cyclohexanone.

[0153] The (D) high-boiling point solvent is not particularly limited as long as it can dissolve each component of the composition for forming a wafer edge protective film of the present invention, and may be any of hydrocarbons, alcohols, ketones, esters, ethers, chlorinated solvents, etc., but specific examples include 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-Hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin, n-nonyl acetate, monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol-n-butyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol mono-n-propyl ether, tripropylene glycol mono-n-butyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triacetin, propylene glycol diacetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, 1,Examples of the diester include 6-hexanediol diacetate, triethylene glycol diacetate, γ-butyrolactone, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, dihexyl malonate, diethyl succinate, dipropyl succinate, dibutyl succinate, dihexyl succinate, dimethyl adipate, diethyl adipate, and dibutyl adipate, and these may be used alone or in combination.

[0154] The (D) high-boiling-point solvent may be appropriately selected from the above-mentioned solvents, depending on the temperature at which the wafer edge protection film composition is heat-treated. The (D) high-boiling-point solvent preferably has a boiling point of 180°C to 300°C, and more preferably 200°C to 300°C. Such a boiling point prevents the solvent from volatilizing too quickly during baking (heat treatment) due to a boiling point that is too low, thereby ensuring sufficient thermal fluidity during film formation and enabling the formation of a wafer edge protection film with excellent uniformity of application, even on wafer edges that are difficult to coat. Furthermore, such a boiling point prevents the solvent from remaining in the film without volatilizing after baking due to a boiling point that is too high, thereby preventing adverse effects on film properties such as etching resistance.

[0155] When a high-boiling solvent (D) is used, its blending amount is preferably 1 to 200 parts by mass, more preferably 1 to 100 parts by mass, per 100 parts by mass of the resin (A). This blending amount is preferable because it avoids the risk of the blending amount being too small to impart sufficient thermal fluidity during baking, or the blending amount being too large to remain in the film and lead to deterioration of film properties such as etching resistance.

[0156] [(E) Surfactant] A surfactant (E) can be added to the wafer edge protective film-forming composition to improve the coating properties during spin coating. Examples of surfactants that can be used include those described in paragraphs

[0142] to

[0147] of JP-A-2009-269953. When a surfactant is added, the amount of surfactant added is preferably 0.001 to 20 parts by mass, more preferably 0.01 to 10 parts by mass, per 100 parts by mass of the resin (A).

[0157] [(F) Acid generator] To further accelerate the curing reaction, an acid generator (F) can be added to the wafer edge protective film-forming composition. Acid generators include those that generate acid by thermal decomposition and those that generate acid by light irradiation, and either can be added. Specifically, materials described in paragraphs

[0061] to

[0085] of JP 2007-199653 A can be added, but are not limited to these.

[0158] The acid generators can be used alone or in combination of two or more. When an acid generator is added, the amount added is preferably 0.05 to 50 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the resin (A).

[0159] [(G) Plasticizer] Furthermore, a plasticizer (G) can be added to the composition for forming a wafer edge protective film to further improve film-forming properties on the wafer edge. The plasticizer is not particularly limited, and a wide variety of known plasticizers can be used. Examples include low-molecular-weight compounds such as phthalates, adipates, phosphates, trimellitates, and citrates, as well as polymers such as polyethers, polyesters, and polyacetal polymers described in JP 2013-253227 A. When a plasticizer is added, the amount added is preferably 5 to 500 parts by mass, more preferably 10 to 200 parts by mass, per 100 parts by mass of the resin (A).

[0160] In addition to the above, the composition for forming a wafer edge protective film may contain additives to further improve film-forming properties on the wafer edge. The additives are not particularly limited as long as they contribute to improving thermal fluidity and impart film-forming properties to the wafer edge. For example, liquid additives having a polyethylene glycol or polypropylene glycol structure, or thermally decomposable polymers having a weight loss rate of 40% or more between 30°C and 250°C and a weight-average molecular weight of 300 to 200,000 are preferably used. The thermally decomposable polymers preferably contain repeating units having an acetal structure represented by the following general formulas (DP1) and (DP1a):

[0161] [ka] (In the formula, R6 is a hydrogen atom or an optionally substituted saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms. Y is a saturated or unsaturated divalent organic group having 2 to 30 carbon atoms.)

[0162] [ka] (In the formula, R 6a is an alkyl group having 1 to 4 carbon atoms. a is a saturated or unsaturated divalent hydrocarbon group having 4 to 10 carbon atoms, which may have an ether bond; and n represents the average number of repeating units and is 3 to 500.

[0163] [Pattern formation method] Further, the present invention provides a method for forming a pattern on a substrate to be processed by forming a protective film on a peripheral edge of the substrate to be processed on which a film having a pattern is formed, the method comprising the steps of: (I-1) a step of applying a protective film-forming composition containing an aromatic ring-containing resin (A) having an organic group represented by the general formula (1) and a solvent to the peripheral edge of a substrate to be processed on which a patterned film has been formed; (I-2) a step of curing the applied protective film-forming composition by heat treatment or light irradiation to form a protective film on the peripheral edge of the substrate; (I-3) forming a pattern on the substrate to be processed by dry etching using the patterned film as a mask; (I-4) removing the protective film; The present invention provides a pattern forming method comprising the steps of:

[0164] An example of the pattern formation method of the present invention will be specifically described with reference to FIG. 6. First, in step (I-1), a substrate 1 to be processed, on which a patterned film 7 has been formed, is placed on a spin chuck (FIG. 6(O)), and the protective film-forming composition 8 of the present invention is applied to the peripheral edge of the substrate 1 from a supply nozzle 3 (FIG. 6(P)). Next, in step (I-2), the applied protective film-forming composition 8 is cured by heat treatment or light irradiation to form a protective film 8A on the peripheral edge (FIG. 6(Q)). Next, in step (I-3), a pattern 1A is formed on the substrate 1 to be processed by dry etching using the patterned film 7 as a mask (FIG. 6(R)). Then, in step (I-4), the patterned film 7 is removed (FIG. 6(S)), and then the protective film 8A is removed (FIG. 6(T)).

[0165] If the wafer edge is damaged by dry etching, particles generated from the wafer edge may fly toward the center of the wafer, potentially causing pattern bridging, breaks, etc. On the other hand, with the pattern formation method of the present invention, the peripheral edges on the front side and back side of the substrate to be processed are protected by a wafer edge protection film, so that defects generated from the wafer edge can be suppressed during the dry etching process, making it possible to form a pattern on the substrate to be processed with high precision and few defects.

[0166] The film having a pattern formed on the substrate to be processed is not particularly limited, and examples thereof include a resist top layer film, a silicon-containing resist intermediate film, an inorganic hard mask intermediate film, a resist underlayer film, etc. Since the substrate to be processed is processed using the film having a pattern as a mask, if a protective film can be formed on the wafer edge using a composition for forming a wafer edge protective film before dry etching is started, particle generation from the wafer edge can be suppressed, and therefore the film having a pattern is preferably a resist top layer film.

[0167] The pattern forming method of the present invention is suitable for use in multilayer resist processes such as a silicon-containing two-layer resist process, a three-layer resist process using a resist underlayer film and a silicon-containing resist intermediate film, a four-layer resist process using a resist underlayer film, an inorganic hard mask intermediate film and an organic thin film, and a silicon-free two-layer resist process. Therefore, a silicon-containing resist intermediate film, an inorganic hard mask intermediate film, an organic thin film, a resist underlayer film, etc. may be formed between the resist top layer film on which a pattern is formed and the substrate to be processed, or a resist underlayer film, etc. may be formed between the silicon-containing resist intermediate film, inorganic hard mask intermediate film, and the substrate to be processed.

[0168] When forming a resist underlayer film, the resist underlayer film can be formed by a method using a coating type organic underlayer film material, a CVD method, an ALD method, or the like. Coating-type organic underlayer film materials include those described in JP 2012-1687 A, JP 2012-77295 A, JP 2004-264710 A, JP 2005-043471 A, JP 2005-250434 A, JP 2007-293294 A, JP 2008-65303 A, JP 2004-205685 A, JP 2007-171895 A, JP 2009-14816 A, JP 2007-199653 A, JP 2008-274250 A, JP 2010-122656 A, and JP 2012-214720 A. Examples of resins and compositions include those disclosed in JP 2014-29435 A, WO 2012 / 077640 A, WO 2010 / 147155 A, WO 2012 / 176767 A, JP 2005-128509 A, JP 2006-259249 A, JP 2006-259482 A, JP 2006-293298 A, JP 2007-316282 A, JP 2012-145897 A, JP 2017-119671 A, and JP 2019-44022 A. Alternatively, the resist underlayer film material may contain metal atoms such as Sn, In, Ga, Ge, Al, Ce, La, Cs, Zr, Hf, Ti, Bi, Sb, and Zn.

[0169] When forming an inorganic hard mask intermediate film, a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiON film) is formed by a CVD method, an ALD method, or the like. Methods for forming nitride films are described in JP 2002-334869 A and WO 2004 / 066377 A. The thickness of the inorganic hard mask intermediate film is 5 to 3,000 nm, preferably 10 to 2,000 nm. Among them, a SiON film, which is highly effective as an anti-reflection film, is most preferably used for ArF exposure applications.

[0170] A polysilsesquioxane-based resist interlayer is preferably used as the silicon-containing resist interlayer. Polysilsesquioxane-based resist interlayers can easily be made to have an anti-reflection effect during excimer exposure, thereby suppressing reflected light during pattern exposure of the resist top layer, resulting in excellent resolution. For 193 nm exposure in particular, using a material containing many aromatic groups as the resist bottom layer increases the k value and increases substrate reflection, but suppressing reflection with the resist interlayer can reduce substrate reflection to 0.5% or less. For 248 nm and 157 nm exposure, anthracene is preferred, while for 193 nm exposure, polysilsesquioxane is preferred, which has pendant light-absorbing groups containing phenyl groups or silicon-silicon bonds and is crosslinked by acid or heat.

[0171] In the pattern formation method, the resist top layer film may be either positive or negative, and the same photoresist composition as commonly used may be used. The photoresist composition may also contain metal atoms such as Sn, In, Ga, Ge, Al, Ce, La, Cs, Zr, Hf, Ti, Bi, Sb, and Zn. When forming the resist top layer film using the photoresist composition, it may be formed by spin coating or by vapor deposition using CVD or ALD.

[0172] When forming a photoresist composition by spin coating, the resist is prebaked after application, preferably at 60 to 180°C for 10 to 300 seconds. Then, exposure is performed according to a conventional method, followed by post-exposure baking (PEB) and development to obtain a resist pattern. The thickness of the resist top layer film is not particularly limited, but is preferably 10 to 500 nm, and more preferably 20 to 400 nm.

[0173] When a photoresist composition is formed by deposition using CVD or ALD, the resist composition is an EUV-sensitive metal oxide film, and the metal is selected from Sn, Zr, Hf, Ti, Bi, Sb, etc., with Sn being preferred due to its excellent EUV sensitivity. The metal oxide-containing film may be a photosensitive organometallic oxide film such as an organotin oxide (e.g., haloalkyltin, alkoxyalkyltin, or amidoalkyltin). Specific examples of suitable precursors include trimethyltin chloride, dimethyltin dichloride, methyltin trichloride, tris(dimethylamino)methyltin(IV), and (dimethylamino)trimethyltin(IV).

[0174] Metal oxide films may be deposited by PECVD or PEALD, using, for example, a Lam Vector® tool. In the ALD example, the Sn oxide precursor is separated from the O precursor / plasma. The deposition temperature is preferably in the range of 50°C to 600°C. The deposition pressure is preferably between 100 and 6000 mTorr. The metal oxide-containing film precursor liquid flow rate (e.g., organotin oxide precursor) may be 0.01 to 10 cm³, and the gas flow rate (CO₂, CO₂, Ar, N₂) may be 100 to 10,000 sccm. The plasma power may be 200 to 1,000 W per 300 mm wafer station using a high-frequency plasma (e.g., 13.56 MHz, 27.1 MHz, or higher). The deposition thickness is preferably 100 to 2,000 Å.

[0175] Examples of exposure light include high energy rays with a wavelength of 300 nm or less, specifically excimer lasers with wavelengths of 248 nm, 193 nm, and 157 nm, soft X-rays with wavelengths of 3 to 20 nm, electron beams, and X-rays.

[0176] After forming a pattern on the substrate to be processed, the method for removing the wafer edge protection film from the wafer edge of the substrate to be processed is preferably removal by dry etching. When removing by dry etching, since the wafer edge protection film is made of an organic film, it can be removed by etching using an oxygen-based or hydrogen-based gas.

[0177] For example, if the substrate is made of Si, SiO2, SiN, SiON, or a silica-based low-dielectric-constant insulating film, it will be resistant to etching using oxygen-based or hydrogen-based gases, making it possible to remove the wafer edge protection film without damaging the wafer edge of the substrate being processed.

[0178] If the wafer edge is damaged by dry etching, particles generated from the wafer edge may fly toward the wafer center, potentially causing pattern bridging or breakage. On the other hand, with the pattern formation method of the present invention, the peripheral edges on the front side and back side of the substrate to be processed are protected by a wafer edge protection film, which can suppress defects from the wafer edge during the dry etching process and enable high-precision, low-defect pattern formation on the substrate to be processed. Furthermore, it is possible to suppress the risk of particles generated during etching of a film containing metal atoms adhering to the wafer edge, resulting in metal contamination of the wafer edge.

[0179] Additionally, the present invention provides a method for forming a protective film on a peripheral edge of a substrate to be processed and forming a pattern on the substrate to be processed, comprising the steps of: (II-1) a step of applying a protective film-forming composition containing an aromatic ring-containing resin (A) having an organic group represented by the general formula (1) and a solvent to the peripheral edge of a substrate to be processed; (II-2) A step of curing the applied protective film-forming composition by heat treatment or light irradiation to form a protective film on the peripheral edge of the substrate to be processed; (II-3) forming a resist upper layer film pattern on the substrate to be processed, and using the resist upper layer film pattern as a mask to form a pattern on the substrate to be processed by dry etching; (II-4) removing the protective film; The present invention provides a pattern forming method comprising the steps of:

[0180] An example of the pattern formation method of the present invention will be specifically described with reference to FIG. 7. First, in step (II-1), the protective film-forming composition 9 of the present invention is applied from a supply nozzle 3 to the peripheral edge of a workpiece substrate placed on a spin chuck. The workpiece substrate may have a workpiece layer 10 formed thereon, such as a silicon-containing resist intermediate film, an inorganic hard mask intermediate film, an organic thin film, or a resist underlayer film (FIG. 7(U)). Next, in step (II-2), the applied protective film-forming composition 9 is cured by heat treatment or light irradiation to form a protective film 9A on the peripheral edge (FIG. 7(V)). Next, in (II-3), a resist upper layer film 11 is formed on the workpiece layer 10 (FIG. 7(W)), and exposed to light to form a resist upper layer film pattern 11A (FIG. 7(X)). Next, using the pattern 11A as a mask, a pattern 10A is formed in the process layer 10 by dry etching (FIG. 7(Y)), and further using the pattern 10A as a mask, a pattern 1A is formed in the process substrate by dry etching (FIG. 7(Z)). Then, in step (II-4), the process layer 10 having the pattern 10A is removed (FIG. 7(AA)), and then the protective film 9A is removed (FIG. 7(AB)).

[0181] The pattern formation method described above can suppress particle generation from the wafer edge when dry etching a substrate to be processed. Furthermore, when forming a resist top layer film, it is possible to avoid the risk of contamination of these areas due to the chemical solution supplied to the front surface of the substrate flowing around to the periphery of the back surface, resulting in the formation of a coating film on these unintended periphery of the back surface.

[0182] When forming a resist upper layer film using the photoresist composition, a spin coating method is preferred. When forming a photoresist composition by spin coating, pre-baking is performed after resist application, preferably at 60 to 180°C for 10 to 300 seconds. Thereafter, exposure is performed according to a conventional method, followed by post-exposure baking (PEB) and development to obtain a resist upper layer film pattern. The thickness of the resist upper layer film is not particularly limited, but is preferably 10 to 500 nm, particularly 20 to 400 nm.

[0183] In the above-described pattern forming method, the resist upper layer film may be either positive or negative, and the same photoresist compositions as those commonly used and metal atom-containing photoresist compositions can be used.

[0184] When the resist top layer film used in the pattern formation method is a composition containing metal atoms, the pattern formation method using the wafer edge protective film-forming composition of the present invention is particularly effective in terms of suppressing contamination of the wafer edges on the front and back sides. Therefore, the resist top layer film is preferably formed from a composition containing metal atoms.

[0185] When the photoresist composition contains a metal atom, the metal atom is preferably Sn, In, Ga, Ge, Al, Ce, La, Cs, Zr, Hf, Ti, Bi, Sb, or Zn, and particularly preferably Sn, Zr, Hf, or Ti.

[0186] Examples of exposure light include high-energy rays with a wavelength of 300 nm or less, specifically excimer lasers with wavelengths of 248 nm, 193 nm, and 157 nm, soft X-rays with wavelengths of 3 to 20 nm, electron beams, X-rays, etc. Among these, extreme ultraviolet rays with wavelengths of 3 to 15 nm are preferred.

[0187] In the pattern formation method, a silicon-containing resist intermediate film, an inorganic hard mask intermediate film, an organic thin film, a resist underlayer film, or the like may be formed between the substrate to be processed and the resist upper layer film.

[0188] The pattern formation method can include a step of applying the composition for forming a wafer edge protectant of the present invention to a substrate to be processed, a substrate on which a resist underlayer film has been formed, a substrate on which a resist underlayer film and a silicon-containing resist intermediate film or an inorganic hard mask have been formed, a substrate on which a resist underlayer film, an inorganic hard mask, and an organic thin film have been formed, or a substrate on which a silicon-containing resist intermediate film or an inorganic hard mask has been formed, to form a wafer edge protectant film, and then applying a resist top layer film.

[0189] The pattern formation method of the present invention is suitable for use in multilayer resist processes such as a silicon-containing two-layer resist process, a three-layer resist process using a resist underlayer film and a silicon-containing resist intermediate film, a four-layer resist process using a resist underlayer film, an inorganic hard mask intermediate film and an organic thin film, and a silicon-free two-layer resist process.

[0190] After forming a pattern on the substrate to be processed, the method for removing the wafer edge protection film of the present invention from the wafer edge of the substrate to be processed is preferably removal by dry etching. When removing by dry etching, since the wafer edge protection film is made of an organic film, it can be removed by etching using an oxygen-based or hydrogen-based gas.

[0191] For example, if the substrate is made of Si, SiO2, SiN, SiON, or silica-based low-dielectric-constant insulating film, it will be resistant to etching using oxygen-based or hydrogen-based gases, making it possible to remove the wafer edge protection film without damaging the wafer edge of the substrate being processed.

[0192] If the wafer edge is damaged by dry etching, particles generated from the wafer edge may fly toward the center of the wafer, potentially causing pattern bridging or breakage. On the other hand, the pattern formation method of the present invention protects the peripheral edges of the front and back sides of the substrate to be processed with a wafer edge protection film that has excellent dry etching resistance, thereby suppressing defects from the wafer edge during the dry etching process and enabling high-precision, low-defect pattern formation on the substrate to be processed. Furthermore, when the resist top layer film used in the pattern formation method is a composition containing metal atoms, the pattern formation method using the wafer edge protection film-forming composition of the present invention is particularly effective in suppressing contamination of the front and back sides of the wafer edges. [Example]

[0193] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The molecular weight and dispersity were measured by the following methods. The weight average molecular weight (Mw) and dispersity (Mw / Mn) in terms of polystyrene were determined by gel permeation chromatography (GPC) using tetrahydrofuran as an eluent.

[0194] [Synthesis example] In the following synthesis examples, the following compound group G: (G1) to (G8) and modifying agents H: (H1) to (H6) were used.

[0195] Compound group G: (G1) to (G8) are shown below. [ka]

[0196] Modification group H: (H1) to (H6) are shown below. [ka]

[0197] [Synthesis Example 1] Synthesis of Compound (B-1) Under a nitrogen atmosphere, 20.0 g of compound (G1) from the raw material group, 16.4 g of modifying agent (H1), and 23.3 g of potassium carbonate were added to 200 g of N-methylpyrrolidone, and the mixture was allowed to react at an internal temperature of 140 °C for 24 hours. After cooling to room temperature, 300 ml of methyl isobutyl ketone and 300 ml of pure water were added to the reaction solution and homogenized, and the separated aqueous layer was removed. The organic layer was then washed twice with 100 ml of 3% aqueous nitric acid solution and five times with 100 ml of pure water, after which the organic layer was evaporated to dryness under reduced pressure. 100 g of THF was added to the residue to form a homogenous solution, which was then crystallized from 350 g of methanol. The precipitated crystals were separated by filtration, washed twice with 200 g of methanol, and then recovered. The recovered crystals were dried under vacuum at 70 °C to obtain the flow promoter compound (B-1).

[0198] The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (B-1): Mw = 580, Mw / Mn = 1.03 [ka]

[0199] [Synthesis Example 2] Synthesis of Compound (B-2) Under a nitrogen atmosphere, 45.5 g of compound (G2) from the raw material group, 9.8 g of potassium carbonate, and 150 g of DMF were added to form a uniform dispersion at an internal temperature of 50°C. 17.6 g of modifying agent (H2) was slowly added, and the reaction was carried out at an internal temperature of 50°C for 24 hours. 300 ml of methyl isobutyl ketone and 300 g of pure water were added to the reaction solution to dissolve the precipitated salt, and the separated aqueous layer was then removed. The organic layer was further washed six times with 100 g of 3% aqueous nitric acid solution and 100 g of pure water, and then evaporated to dryness under reduced pressure to obtain compound (B-2) for use as a flow promoter.

[0200] The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (B-2): Mw = 965, Mw / Mn = 1.08 [ka]

[0201] [Synthesis Example 3] Synthesis of Compound (B-3) Under a nitrogen atmosphere, 46.9 g of compound (G2), 10.1 g of potassium carbonate, and 150 g of DMF were added and a uniform dispersion was obtained at an internal temperature of 50°C. 9.0 g of modifying agent (H2) was slowly added, and the reaction was carried out at an internal temperature of 50°C for 24 hours. 300 ml of methyl isobutyl ketone and 300 g of pure water were added to the reaction solution to dissolve the precipitated salt, and the separated aqueous layer was then removed. The organic layer was further washed six times with 100 g of 3% aqueous nitric acid solution and 100 g of pure water, and then evaporated to dryness under reduced pressure to obtain compound (B-3) for use as a flow promoter.

[0202] The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (B-3): Mw = 903, Mw / Mn = 1.08 [ka]

[0203] [Synthesis Example 4] Synthesis of Compound (B-4) Under a nitrogen atmosphere, 47.2 g of compound (G3), 11.7 g of potassium carbonate, and 150 g of DMF were added and a uniform dispersion was obtained at an internal temperature of 50°C. 8.6 g of modifying agent (H3) was slowly added, and the reaction was carried out at an internal temperature of 50°C for 24 hours. 300 ml of methyl isobutyl ketone and 300 g of pure water were added to the reaction solution to dissolve the precipitated salt, and the separated aqueous layer was then removed. The organic layer was further washed six times with 100 g of 3% aqueous nitric acid solution and 100 g of pure water, and then evaporated to dryness under reduced pressure to obtain compound (B-4) for use as a flow promoter.

[0204] The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (B-4): Mw = 724, Mw / Mn = 1.01 [ka]

[0205] [Synthesis Example 5] Synthesis of Compound (B-5) Under a nitrogen atmosphere, 100 g of N-methylpyrrolidone was added to 30.00 g of compound (G4) from the raw material group. A homogeneous solution was then formed under a nitrogen atmosphere at an internal temperature of 40°C. Then, 13.7 g of modifying agent (H4) was added and the reaction was carried out for 3 hours at an internal temperature of 40°C to obtain an amic acid solution. 200 g of o-xylene was added to the resulting amic acid solution, and the reaction was carried out for 9 hours at an internal temperature of 150°C while removing the low-boiling substances and water produced from the system, resulting in dehydration and imidization. After the reaction was completed, the mixture was cooled to room temperature and crystallized in 1000 g of methanol. The precipitated crystals were separated by filtration, washed twice with 500 g of methanol, and recovered. The recovered crystals were dried under vacuum at 70°C to obtain the flow promoter compound (B-5).

[0206] The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (B-5): Mw = 930, Mw / Mn = 1.01 [ka]

[0207] [Synthesis Example 6] Synthesis of polymer (B-6) Under a nitrogen atmosphere, 44.7 g of compound (G5) from the raw material group, 16.5 g of potassium carbonate, and 150 g of DMF were added to form a uniform dispersion at an internal temperature of 50°C. 16.5 g of modifying agent (H2) was slowly added, and the reaction was carried out at an internal temperature of 50°C for 24 hours. 300 ml of methyl isobutyl ketone and 300 g of pure water were added to the reaction solution to dissolve the precipitated salt, and the separated aqueous layer was then removed. The organic layer was further washed six times with 100 g of 3% aqueous nitric acid solution and 100 g of pure water, and then evaporated to dryness under reduced pressure to obtain polymer (B-6) for use as a fluidity promoter.

[0208] The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (B-6): Mw = 2500, Mw / Mn = 3.10 [ka]

[0209] [Synthesis Example 7] Synthesis of polymer (B-7) Under a nitrogen atmosphere, 20.0 g of resin (G6), 34.5 g of potassium carbonate, and 100 g of DMF were added and a uniform dispersion was obtained at an internal temperature of 50°C. 23.8 g of modifying agent (H2) was slowly added, and the reaction was carried out at an internal temperature of 50°C for 24 hours. 300 ml of methyl isobutyl ketone and 300 g of pure water were added to the reaction solution to dissolve the precipitated salt, and the separated aqueous layer was then removed. The organic layer was further washed six times with 100 g of 3% aqueous nitric acid solution and 100 g of pure water, and then evaporated to dryness under reduced pressure to obtain polymer (B-7) for use as a fluidity promoter.

[0210] The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (B-7): Mw = 9,400, Mw / Mn = 3.59 [ka]

[0211] [Synthesis Example 8] Synthesis of polymer (B-8) Under a nitrogen atmosphere, 20.0 g of resin (G6), 27.6 g of potassium carbonate, and 100 g of DMF were added and a uniform dispersion was obtained at an internal temperature of 50°C. 15.8 g of modifying agent (H2) was slowly added, and the reaction was carried out at an internal temperature of 50°C for 24 hours. 300 ml of methyl isobutyl ketone and 300 g of pure water were added to the reaction solution to dissolve the precipitated salt, and the separated aqueous layer was then removed. The organic layer was further washed six times with 100 g of 3% aqueous nitric acid solution and 100 g of pure water, and then evaporated to dryness under reduced pressure to obtain polymer (B-8) for use as a fluidity promoter.

[0212] The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (B-8): Mw = 9,200, Mw / Mn = 3.53 [ka]

[0213] [Synthesis Example 9] Synthesis of Compound (B-9) 51.0 g of epoxy compound (G7), 56.6 g of modifying agent (H5), and 600 g of 2-methoxy-1-propanol were mixed under a nitrogen atmosphere at an internal temperature of 100°C to form a homogeneous solution, and then 5.7 g of benzyltriethylammonium chloride was added and stirred at an internal temperature of 120°C for 12 hours. After cooling to room temperature, 1,500 g of methyl isobutyl ketone was added, and the organic layer was washed five times with 300 g of pure water. The organic layer was evaporated to dryness under reduced pressure to obtain a flow promoter compound (B-9).

[0214] The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (B-9): Mw = 900, Mw / Mn = 1.04 [ka]

[0215] [Comparative Synthesis Example 1] Synthesis of comparative compound (R-2) 77.5 g of compound (G8) from the raw material group, 47.0 g of modifying agent (H6), and 600 g of 2-methoxy-1-propanol were mixed under a nitrogen atmosphere at an internal temperature of 100°C to form a homogeneous solution, and then 5.7 g of benzyltriethylammonium chloride was added and stirred at an internal temperature of 120°C for 12 hours. After cooling to room temperature, 1,500 g of methyl isobutyl ketone was added, and the organic layer was washed five times with 300 g of pure water. The organic layer was solidified under reduced pressure to obtain compound (R-2).

[0216] The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (R-2): Mw=960, Mw / Mn=1.03. [ka]

[0217] [Comparative Synthesis Example 2] Synthesis of Comparative Polymer (R-4) Under a nitrogen atmosphere, 60.0 g of 2-vinylnaphthalene, 40.0 g of vinylbenzyl alcohol, 300 g of methyl ethyl ketone, and 5.0 g of dimethyl 2,2-azobisisobutyrate were added and reacted at an internal temperature of 80°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature and crystallized in 3,000 g of heptane. The precipitated crystals were separated by filtration, washed twice with 500 g of heptane, and then recovered. The recovered crystals were dried in vacuo at 70°C to obtain polymer (R-4).

[0218] The weight average molecular weight (Mw) and dispersity (Mw / Mn) were determined by GPC, and the following results were obtained. (R-4): Mw = 4,500, Mw / Mn = 2.0. [ka]

[0219] [Comparative Synthesis Example 3] Synthesis of Comparative Polymer (R-5) A 2L flask was charged with 17.8g of 4-hydroxyphenyl methacrylate and 50g of tetrahydrofuran as a solvent. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassed under reduced pressure and nitrogen blown three times. After warming to room temperature, 1.2g of AIBN (azobisisobutyronitrile) was added as a polymerization initiator, and the temperature was raised to 60°C, followed by a reaction for 15 hours. The reaction solution was added to 1L of isopropyl alcohol solution to precipitate, and the resulting white solid was filtered and dried under reduced pressure at 60°C to obtain a white polymer (R-5).

[0220] By GPC weight The average molecular weight (Mw) and dispersity (Mw / Mn) were determined, and the following results were obtained. (R-5): Mw = 11,000, Mw / Mn = 2.11. [ka]

[0221] The structures of the compounds and polymers used in the obtained compositions for forming a wafer edge protective film, as well as the weight average molecular weight (Mw) and dispersity (Mw / Mn) are shown in Tables 1 and 2. For the comparative polymer (R-1), (G5) of raw material group G, which was used as a raw material in the synthesis examples, was used, and for the comparative polymer (R-3), (G6) of raw material group G was used.

[0222] [Table 1]

[0223] [Table 2]

[0224] [(C) Crosslinking agent] The crosslinking agents (C) used in the compositions for forming wafer edge protective films are shown below. [ka]

[0225] [(D) High boiling point solvent] The (D) high boiling point solvent (Diethylene Glycol Monobenzyl Ether: boiling point 302° C.) used in the composition for forming a wafer edge protective film is shown below. [ka]

[0226] [(F) Thermal acid generator] The thermal acid generators (F) used in the compositions for forming wafer edge protective films are shown below. [ka]

[0227] [Composition for forming wafer edge protective film EPF-1] Resin (A) was prepared by dissolving the flow promoter compound (B-1) in propylene glycol monomethyl ether acetate (PGMEA) containing 0.5 mass% of surfactant FC-4430 (manufactured by Sumitomo 3M Limited) in the proportions shown in Table 3, and filtering the resulting solution through a 0.02 μm membrane filter to prepare a composition for forming a wafer edge protective film (EPF-1).

[0228] [Compositions for forming wafer edge protective films EPF-2 to 12 and comparative examples EPF-1 to 5] Except for the type and content of each component as shown in Table 3, the same procedure as for EPF-1 was performed. preparation In Table 3, "-" indicates that the corresponding ingredient was not used.

[0229] [Table 3]

[0230] [Examples 1-1 to 12, Comparative Examples 1-1 to 5: Evaluation of wafer edge protection film thickness and defect evaluation] The above-mentioned compositions for forming a wafer edge protective film (EPF-1 to 12 and Comparative Examples EPF-1 to 5) were supplied to the peripheral edge (wafer edge) of a silicon wafer and spin-coated to form a protective film on the wafer edge. The wafer was then baked for 60 seconds at each temperature shown in Table 4 to harden the protective film formed on the wafer edge.

[0231] The thickness of the protective film formed on the wafer edge was evaluated by cross-sectional observation using an electron microscope (S-4700) manufactured by Hitachi, Ltd. As shown in Figure 8, the evaluation points were the surface of the wafer edge (1.5 mm from the periphery Wb toward the center of the wafer) and the wafer apex.

[0232] The number of defects in the protective film fabricated on the wafer edge was also evaluated using VisEdge manufactured by KLA-Tencor Corp. If the number of defects on the wafer edge protective film was less than 30, it was rated as "A" (very good), if it was 30 to less than 100, it was rated as "B" (good), and if it was 100 or more, it was rated as "C" (poor).

[0233] [Table 4]

[0234] As shown in Table 4, the wafer edge protection film formation method using the wafer edge protection film formation compositions (EPF-1 to EPF-12) of the present invention can provide good coverage from the surface of the wafer edge to the apex, and can also form a protection film with excellent defect suppression. It is believed that the inclusion of the organic group of general formula (1), which has excellent thermal fluidity, makes it possible to correct deformation of the protection film surface that occurs when the wafer edge protection film is applied by spin coating, by the thermal flow of the resin. On the other hand, the wafer edge protection film formation method using comparative examples EPF-1 to 5, which do not have the organic group represented by general formula (1), as in comparative examples 1-1 to 1-5, resulted in noticeable defects on the wafer edge protection film.

[0235] Furthermore, compositions for forming wafer edge protective films (EPF-3, 4, 6, 8, 10 to 12) containing resins having hydroxyl groups in addition to the organic group represented by general formula (1) showed particularly excellent film-forming properties. The presence of hydroxyl groups in addition to the organic group represented by general formula (1) improves wettability and adhesion to the substrate, and we presume that these compositions for forming wafer edge protective films (EPF-3, 4, 6, 8, 10 to 12) containing resins having both the organic group represented by general formula (1) and hydroxyl groups exhibited superior film-forming properties compared to resins containing only the organic group represented by general formula (1).

[0236] [Examples 2-1 to 2-12 and Comparative Examples 2-1 to 2-5: Etching Resistance Evaluation] The wafer edge protection film-forming compositions (EPF-1 to 12 and Comparative Examples EPF-1 to 5) prepared above were applied to the surface of a silicon substrate and baked in air at the temperatures shown in Table 5 for 60 seconds to form a 1200 nm coating film, and the film thickness A was measured. Next, etching was performed for 1 minute using CF4 gas and O2 gas under the following conditions using a Tokyo Electron Telius etching system, and the film thickness B was measured. The film thickness etched in 1 minute (film thickness B - film thickness A) was calculated as the etching resistance. For CF4 gas etching, a film thickness difference between B and A of less than 75 nm was rated "A" (very good), a film thickness difference between 75 nm or more and less than 80 nm was rated "B" (good), and a film thickness difference of 80 nm or more was rated "C" (poor). For O2 gas etching, a film thickness difference between B and A of less than 110 nm was rated "A" (very good), a film thickness difference between 110 nm or more and less than 120 nm was rated "B" (good), and a film thickness difference of 120 nm or more was rated "C" (poor). The results are shown in Table 5.

[0237] Dry etching conditions with CF4 gas Chamber pressure: 100mT RF power (top): 500W RF power (bottom): 400W CF4 gas flow rate: 300sccm Time: 60sec

[0238] Dry etching conditions with O2 gas Chamber pressure: 15mT RF power (top): 300W RF power (bottom): 50W O2 gas flow rate: 30sccm N2 gas flow rate: 270sccm Time: 60sec

[0239] [Table 5]

[0240] As shown in Table 5, the compositions for forming a wafer edge protective film of the present invention (EPF-1 to EPF- - 12) was found to have excellent dry etching resistance against CF4 gas and O2 gas. It is presumed that the resin has an aromatic ring with a high carbon content and an organic group represented by general formula (1), and that the organic group represented by general formula (1) exhibits excellent reactivity, allowing the formation of a dense cured film and providing excellent dry etching resistance. In particular, compositions for forming wafer edge protection films (EPF-1 to 6, EPF-10 to 11) using a resin containing a cardo structure and an organic group represented by general formula (1) were found to exhibit extremely excellent resistance. Comparative examples EPF-1 and EPF-2 also contain a cardo structure, and therefore exhibit excellent dry etching resistance.

[0241] On the other hand, the compositions for forming wafer edge protection films (Comparative Examples EPF-3 to EPF-5) that do not have a cardo structure or an organic group represented by general formula (1) had insufficient dry etching resistance. When EPF-7 and Comparative EPF-3, which have the same core structure, are compared, EPF-7, which has an organic group represented by general formula (1), has superior dry etching resistance. Therefore, it is presumed that the organic group represented by general formula (1) contributes to the formation of a dense cured film.

[0242] As described above, it has been found that the compositions for forming wafer edge protection films (EPF-1 to EPF-12) used in the wafer edge protection film formation method of the present invention have excellent dry etching resistance against CF4 gas and O2 gas. Therefore, the wafer edge protection film formation method using these compositions is expected to function as a protective film that can protect the wafer edge from etchants until etching of the substrate to be processed is complete, even in dry etching processes that form fine patterns with high aspect ratios, such as those used in 3D-NAND memory, which is becoming increasingly highly stacked.

[0243] [Example 3-1, Comparative Example 3-1: Amount of Metallic Impurities on the Surface of the Peripheral Edge of the Wafer] The amount of metal impurities introduced into the wafer peripheral edge by the metal-containing resist top layer film was evaluated. The metal-containing compounds (M-1) to (M-3) used for the evaluation were synthesized as follows.

[0244] [Synthesis of metal-containing compound (M-1)] 340 g of titanium tetrabutoxide was dissolved in 500 g of 1-butanol, and a mixed solution of 27 g of deionized water and 500 g of 1-butanol was added dropwise to the solution at room temperature over 2 hours while stirring. 1,200 g of propylene glycol monomethyl ether acetate (PGMEA) was added to the resulting solution, and the mixture was heated at 50°C under reduced pressure until no more 1-butanol was distilled off, yielding 1,000 g of a PGMEA solution of a titanium-containing compound. The molecular weight measured in terms of polystyrene was found to be Mw = 1,050.

[0245] [Synthesis of metal-containing compound (M-2)] 480 g of an 80% by weight 1-butanol solution of zirconium tetraisopropoxide was dissolved in 400 g of 1-butanol, and a mixed solution of 27 g of deionized water and 500 g of 1-butanol was added dropwise to the resulting solution over 2 hours at room temperature while stirring. 90 g of 1,3-butanediol was added to the resulting solution and stirred at room temperature for 30 minutes. The solution was concentrated under reduced pressure at 30°C and then heated to 60°C and continued to be heated under reduced pressure until no more distillate was produced. When no more distillate was observed, 1,200 g of PGMEA was added and the mixture was heated under reduced pressure at 40°C until no more 1-butanol was produced, yielding 1,000 g of a PGMEA solution of the zirconium-containing compound. The molecular weight in terms of polystyrene was measured to be Mw = 1,400.

[0246] [Synthesis of metal-containing compound (M-3)] 480 g of an 80% by weight 1-butanol solution of hafnium tetraisopropoxide was dissolved in 400 g of 1-butanol, and a mixed solution of 27 g of deionized water and 500 g of 1-butanol was added dropwise over 2 hours at room temperature while stirring. 90 g of 1,3-butanediol was added to the resulting solution and stirred at room temperature for 30 minutes. The solution was concentrated under reduced pressure at 30°C and then heated to 60°C and continued to be heated under reduced pressure until no more distillate was produced. When no more distillate was observed, 1,200 g of PGMEA was added and the mixture was heated under reduced pressure at 40°C until no more 1-butanol was produced, yielding 1,000 g of a PGMEA solution of the hafnium-containing compound. The molecular weight in terms of polystyrene was measured to be Mw = 1,500.

[0247] [Preparation of metal-containing resist] The metal-containing compounds (M-1) to (M-3) obtained in the above synthesis examples were dissolved in a solvent containing 100 ppm of 3M fluorine-based surfactant FC-4430 as a surfactant, in the compositions shown in Table 6. The resulting solutions were filtered through a 0.2 μm filter to prepare metal-containing resists MR-1 to MR-3.

[0248] The compositions in Table 6 below are as follows: Acid generator: PAG-1, 2 (see structural formula below) Basic compound: Base-1 (see structural formula below)

[0249] [ka]

[0250] [ka]

[0251] [Table 6]

[0252] As shown in FIG. 9, the protective film-forming composition (EPF-1) 12 prepared above was applied from a supply nozzle 3 to the peripheral edges of the front and back sides of a silicon substrate (FIG. 9(AD)). The substrate was then baked in air at 350°C for 60 seconds to form a protective film 12A (FIG. 9(AE)). Subsequently, a metal-containing resist upper layer film-forming composition (MR-1 to MR-3) 13 was applied from a resist supply nozzle 14 to the surface of the silicon substrate (FIG. 9(AF)). The substrate was then prebaked on a hot plate at 170°C for 60 seconds to form a 35 nm metal-containing resist upper layer film 13A (FIG. 9(AG)). Next, the metal-containing resist upper layer film 13A was removed using a developer (butyl acetate) (FIG. 9(AH)). The protective film 12A formed on the peripheral edges of the front and back sides of the silicon substrate was then removed by dry etching using O gas (FIG. 9(AI)). The peripheral edges of the front and back sides of the silicon substrate were treated with a mixture of hydrofluoric acid and hydrogen peroxide, and the solution was recovered and evaluated using an Expert VPD-ICP-MS manufactured by IAS Corporation.

[0253] As a comparative example, a metal-containing resist was applied to the surface of a silicon substrate without using a composition for forming a wafer edge protective film. The metal-containing resist had an impurity content of 1.0×10E +10 (atoms / cm 2 ) or less is "A" (good), 1.0 x 10E +10(atoms / cm 2 ) was evaluated as "B" (poor). The results are shown in Table 7.

[0254] [Table 7]

[0255] As shown in Table 7, by forming the wafer edge protective film-forming composition (EPF-1) of the present invention as a protective film on the peripheral edge of the front side and the peripheral edge of the back side, the amount of metal adhering when applying the metal-containing resist to the silicon substrate was significantly less than when the protective film-forming composition was not used, which was favorable.

[0256] From the above, the wafer edge protective film formation method using the wafer edge protective film formation composition of the present invention can provide a wafer edge protective film that has superior dry etching resistance compared to conventional wafer edge protective films and has excellent film-forming properties even on wafer edges that are difficult to cover. Furthermore, by forming a protective film on the peripheral edge of the backside as well, it is possible to avoid the risk of metal contamination in these areas due to the chemical solution supplied to the surface of the substrate flowing around to the peripheral edge of the backside when forming a metal-containing coating film, resulting in the coating film being formed on these unintended peripheral edges of the backside. Therefore, these compositions can be suitably used for forming fine resist patterns in the lithography processes of various electronic devices, such as semiconductor devices and liquid crystal devices, which are expected to become increasingly miniaturized in the future.

[0257] This specification includes the following inventions.

[0258] [1]: A method for forming a protective film on the peripheral edge of a substrate, comprising: (i) a step of coating the peripheral edge of the substrate with a protective film-forming composition containing an aromatic ring-containing resin (A) having an organic group represented by the following general formula (1) and a solvent; and (ii) a step of curing the coated protective film-forming composition by heat or light irradiation to form the protective film on the peripheral edge of the substrate. [ka] (In the formula, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and * is a bonding site.

[0259] [2]: The method for forming a wafer edge protective film according to the above [1], characterized in that the resin (A) further has a hydroxyl group, and the ratio of the number of the hydroxyl group to the number of the organic group represented by the general formula (1) satisfies the relationship a+b=1, 0.1≦b≦0.9, where a is the proportion of the hydroxyl group and b is the proportion of the organic group represented by the general formula (1).

[0260] [3]: The method for forming a wafer edge protective film according to the above [1] or [2], characterized in that the resin (A) is an aromatic ring-containing resin having hydroxyl groups and organic groups represented by the following general formula (1A), and the ratio of the number of the hydroxyl groups to the number of the organic groups represented by the general formula (1A) satisfies the relationship c+d=1, 0.1≦d≦0.9, where c is the proportion of the hydroxyl groups and d is the proportion of the organic groups represented by the general formula (1A). [ka] (In the formula, * represents a binding site.)

[0261] [4]: The method for forming a wafer edge protective film according to [1], [2], or [3], wherein the resin (A) is a compound having a ratio Mw / Mn (i.e., dispersity) of the weight average molecular weight Mw to the number average molecular weight Mn in terms of polystyrene as determined by gel permeation chromatography in the range of 1.00≦Mw / Mn≦1.25.

[0262] [5]: The method for forming a wafer edge protection film according to [1], [2], [3], or [4], wherein the resin (A) is a polymer having a weight average molecular weight of 1,000 to 12,000 in terms of polystyrene as determined by gel permeation chromatography.

[0263] [6]: The method for forming a wafer edge protection film according to [1], [2], [3], [4], or [5] above, characterized in that the resin (A) has at least one structural unit represented by the following general formulas (A-1), (A-2), (A-3), (A-4), and (A-5): [ka] (In the formula, W1 and W2 each independently represent a benzene ring or a naphthalene ring, and the hydrogen atoms in the benzene ring and the naphthalene ring may be substituted with a hydrocarbon group having 1 to 6 carbon atoms. R a is a hydrogen atom or an organic group represented by the following general formula (2), a In the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1 and 0.1≦f≦0.9 is satisfied. Y is a group represented by the following general formula (3): n1 is 0 or 1, n2 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety. [ka] (wherein Z1 is a group represented by the following general formula (4), and R a is a hydrogen atom or an organic group represented by the following general formula (2), a In the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1, 0.1≦f≦0.9 is satisfied. n4 is 0 or 1, n5 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety. [ka] (where * represents the bond site to the oxygen atom, R B is a divalent organic group having 1 to 10 carbon atoms, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. [ka] (* represents a bond.) [ka] (wherein W1, W2, Y, and n1 are the same as above.) [ka] (In the formula, m3 and m4 represent 1 or 2, and Z is a single bond or a structure represented by the following general formula (5). R x is any of the structures represented by the following general formula (6): [ka] (In the formula, * represents a bond, 1 represents an integer of 0 to 3, and R a ~R f each independently represents a hydrogen atom or an optionally fluorine-substituted alkyl group having 1 to 10 carbon atoms, a phenyl group, or a phenylethyl group; R a and R b may be bonded to form a cyclic compound.) [ka] (where * represents the bonding site to the aromatic ring, and Q1 is Carbon number It is a linear saturated hydrocarbon group having 1 to 30 carbon atoms, or a structure represented by the following general formula (7): [ka] (where * represents the bonding site to the carbonyl group, and R i is a hydrogen atom or an organic group represented by the general formula (2), and iIn the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1 and 0.1≦f≦0.9 is satisfied. j represents a linear or branched hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, a nitro group, an amino group, a nitrile group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or an alkanoyloxy group having 1 to 10 carbon atoms. n3 and n4 represent the number of substituents on the aromatic ring, and each represents an integer of 0 to 7, provided that n3 + n4 is 0 or more and 7 or less. n5 represents 0 to 2. [ka] (In the formula, R 1 is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms, X is a divalent organic group having 1 to 30 carbon atoms, and R a is a hydrogen atom or an organic group represented by the general formula (2), and a In the structure constituting the formula (1), when the ratio of hydrogen atoms is e and the ratio of organic groups represented by the general formula (2) is f, the relationship of e+f=1 and 0.1≦f≦0.9 is satisfied. p is an integer of 0 to 5, q1 is an integer of 1 to 6, p+q1 is an integer of 1 or more and 6 or less, and q2 is 0 or 1.

[0264] [7]: The method for forming a wafer edge protective film according to [1], [2], [3], [4], [5], or [6], characterized in that the content of the resin (A) in the composition for forming a protective film is 10 mass% or more.

[0265] [8]: The method for forming a wafer edge protective film according to [1], [2], [3], [4], [5], [6], or [7], characterized in that the composition for forming a protective film further contains one or more of a crosslinking agent, a high-boiling point solvent, a surfactant, an acid generator, and a plasticizer.

[0266] [9]: The method for forming a wafer edge protective film according to [1], [2], [3], [4], [5], [6], [7], or [8], characterized in that in step (i), the protective film is formed also on the peripheral edge of the back side of the substrate by coating the protective film forming composition on the peripheral edge of the back side of the substrate in addition to the peripheral edge of the front side of the substrate, thereby forming the protective film also on the peripheral edge of the back side of the substrate in step (ii).

[0267]

[10] : The method for forming a wafer edge protective film according to [1], [2], [3], [4], [5], [6], [7], [8], or [9], characterized in that the coating in step (i) is performed using a spin coating method, and the protective film is not formed anywhere other than the peripheral edge on the front side and the peripheral edge on the back side of the substrate.

[0268]

[11] : The method for forming a wafer edge protective film according to [1], [2], [3], [4], [5], [6], [7], [8], [9], or

[10] , characterized in that in the step (ii), the coated composition for forming a protective film is cured by heat treatment at a temperature of 100°C or higher and 800°C or lower for 10 to 7,200 seconds.

[0269]

[12] : A method for forming a protective film on the peripheral edge of a workpiece substrate on which a film having a pattern has been formed, and forming a pattern on the workpiece substrate, the method comprising: (I-1) applying a protective film-forming composition to the peripheral edge of the workpiece substrate on which a film having a pattern has been formed, the protective film-forming composition comprising an aromatic ring-containing resin (A) having an organic group represented by the following general formula (1) and a solvent; (I-2) curing the applied protective film-forming composition by heat treatment or light irradiation to form a protective film on the peripheral edge of the substrate; (I-3) using the film having the pattern as a mask to form a pattern on the workpiece substrate by dry etching; and (I-4) removing the protective film. [ka] (In the formula, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and * is a bonding site.

[0270]

[13] : A method for forming a protective film on the peripheral edge of a workpiece substrate and forming a pattern on the workpiece substrate, comprising: (II-1) a step of applying a protective film-forming composition to the peripheral edge of the workpiece substrate, the protective film-forming composition comprising an aromatic ring-containing resin (A) having an organic group represented by the following general formula (1) and a solvent; (II-2) a step of curing the applied protective film-forming composition by heat treatment or light irradiation to form a protective film on the peripheral edge of the workpiece substrate; (II-3) a step of forming a resist upper layer film pattern on the workpiece substrate, and using this as a mask to form a pattern on the workpiece substrate by dry etching; and (II-4) a step of removing the protective film. [ka] (In the formula, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and * is a bonding site.

[0271]

[14] : The pattern forming method described in

[12] or

[13] above, characterized in that in step (I-1) or step (II-1), the protective film-forming composition is applied to the peripheral edge of the back side of the substrate in addition to the peripheral edge of the front side of the substrate, and thereby the protective film is formed also on the peripheral edge of the back side of the substrate in step (I-2) or step (II-2).

[0272]

[15] : A composition for forming a protective film on the peripheral edge of a substrate, the composition for forming a wafer edge protective film comprising an aromatic ring-containing resin (A) having an organic group represented by the following general formula (1) and a solvent: [ka] (In the formula, R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and * is a bonding site.

[0273] The present invention is not limited to the above-described embodiments, which are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that provides similar effects is included within the technical scope of the present invention. [Explanation of symbols]

[0274] 1...substrate (wafer) to be processed, 1A...pattern formed on the substrate to be processed, 2...spin chuck, 3...supply nozzle, 3A...upper supply nozzle, 3B...Downward supply nozzle 4, 5, 6, 8, 9, 12...Protective film forming composition, 4A, 5A, 6A, 8A, 9A, 12A...protective film, 7...film having a pattern, 10...Processed layer; 10A...Pattern formed on the processed layer; 11...resist upper layer film, 11A...resist upper layer film pattern, 13... Composition for forming a metal-containing resist upper layer film, 13A... Metal-containing resist upper layer film, 14...Resist supply nozzle.

Claims

1. A method for forming a protective film on a peripheral edge of a substrate, comprising: (i) coating the peripheral edge of the substrate with a protective film-forming composition containing a resin (A) having at least one structural unit represented by the following general formulas (A-1), (A-2), (A-3), (A-4), and (A-5) and a solvent; (ii) curing the coated protective film-forming composition by heat or light irradiation to form the protective film on the peripheral edge of the substrate; 1. A method for forming a wafer edge protection film, comprising: 【Chemical 1】 (In the formula, W 1 and W 2 each independently represent a benzene ring or a naphthalene ring, and hydrogen atoms in the benzene ring and naphthalene ring may be substituted with a hydrocarbon group having 1 to 6 carbon atoms. R a is a hydrogen atom or an organic group represented by the following general formula (2), and when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. Y is a group represented by the following general formula (3), n 1 is 0 or 1, n 2 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety.) 【Chemistry 2】 (In the formula, Z 1 is a group represented by the following general formula (4), R a is a hydrogen atom or an organic group represented by the following general formula (2), and when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. n 4 is 0 or 1, n 5 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety.) 【Chemistry 3】 (In the formula, * represents a bonding site to an oxygen atom, R B is a divalent organic group having 1 to 10 carbon atoms, and R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms.) 【Chemistry 4】 (* represents a bond.) 【Chemistry 5】 (wherein W 1 , W 2 , Y and n 1 are the same as defined above.) 【Chemistry 6】 (In the formula, m 3 and m 4 represent 1 or 2, Z is a single bond or a structure represented by the following general formula (5), and R x is a structure represented by the following general formula (6).) 【Chemistry 7】 (In the formula, * represents a bond, 1 represents an integer of 0 to 3, and R a to R f each independently represent a hydrogen atom or an optionally fluorine-substituted alkyl group having 1 to 10 carbon atoms, a phenyl group, or a phenylethyl group.) 【Chemistry 8】 (In the formula, * represents the bonding site to the aromatic ring, and Q 1 is a linear saturated hydrocarbon group having 1 to 30 carbon atoms or a structure represented by the following general formula (7).) 【Chemistry 9】 (In the formula, * represents a bonding site to a carbonyl group, R i is a hydrogen atom or an organic group represented by the general formula (2), and when the ratio of hydrogen atoms in the structure constituting R i is e and the ratio of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. R j represents a linear or branched hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, a nitro group, an amino group, a nitrile group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or an alkanoyloxy group having 1 to 10 carbon atoms. n 3 and n 4 represent the number of substituents on the aromatic ring and each represents an integer of 0 to 7, with the proviso that n 3 +n 4 is 0 to 7. n 5 represents 0 to 2.) 【Chemistry 10】 (In the formula, R 1 is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms; X is a divalent organic group having 1 to 30 carbon atoms; R a is a hydrogen atom or an organic group represented by the general formula (2); when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied; p is an integer of 0 to 5; q 1 is an integer of 1 to 6; p+q 1 is an integer of 1 or more and 6 or less; and q 2 is 0.)

2. 2. The method for forming a wafer edge protective film according to claim 1, wherein the resin (A) is a compound having a ratio Mw / Mn (i.e., dispersity) of the weight average molecular weight Mw to the number average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography within the range of 1.00≦Mw / Mn≦1.

25.

3. 2. The method for forming a wafer edge protective film according to claim 1, wherein the resin (A) is a polymer having a weight average molecular weight of 1,000 to 12,000 in terms of polystyrene as determined by gel permeation chromatography.

4. 2. The method for forming a wafer edge protective film according to claim 1, wherein the content of the resin (A) in the composition for forming a protective film is 10% by mass or more.

5. 2. The method for forming a wafer edge protective film according to claim 1, wherein the composition for forming a protective film further contains one or more of a crosslinking agent, a high-boiling point solvent, a surfactant, an acid generator, and a plasticizer.

6. 6. A method for forming a wafer edge protective film according to claim 1, wherein in step (i), the protective film is formed also on the peripheral edge of the back side of the substrate by coating the protective film forming composition on the peripheral edge of the back side of the substrate in addition to the peripheral edge of the front side of the substrate, thereby forming the protective film also on the peripheral edge of the back side of the substrate in step (ii).

7. 6. A wafer edge protective film forming method according to claim 1, characterized in that the coating in step (i) is performed using a spin coating method, and the protective film is not formed on any part of the substrate other than the peripheral edge on the front side and the peripheral edge on the back side.

8. 6. The method for forming a wafer edge protective film according to claim 1, wherein in the step (ii), the coated composition for forming a protective film is cured by heat treatment at a temperature of 100°C or higher and 800°C or lower for 10 to 7,200 seconds.

9. A method for forming a pattern on a substrate to be processed by forming a protective film on a peripheral edge of the substrate to be processed on which a film having a pattern is formed, the method comprising: (I-1) A step of applying a protective film-forming composition containing a resin (A) having at least one structural unit represented by the following general formulas (A-1), (A-2), (A-3), (A-4), and (A-5) and a solvent to the peripheral edge of a substrate to be processed on which a patterned film has been formed; (I-2) A step of curing the applied protective film-forming composition by heat treatment or light irradiation to form a protective film on the peripheral edge of the substrate to be processed; (I-3) forming a pattern on the substrate to be processed by dry etching using the patterned film as a mask; (I-4) removing the protective film; A pattern forming method comprising the steps of: 【Chemistry 11】 (In the formula, W 1 and W 2 each independently represent a benzene ring or a naphthalene ring, and hydrogen atoms in the benzene ring and naphthalene ring may be substituted with a hydrocarbon group having 1 to 6 carbon atoms. R a is a hydrogen atom or an organic group represented by the following general formula (2), and when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. Y is a group represented by the following general formula (3), n 1 is 0 or 1, n 2 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety.) 【Chemistry 12】 (In the formula, Z 1 is a group represented by the following general formula (4), R a is a hydrogen atom or an organic group represented by the following general formula (2), and when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. n 4 is 0 or 1, n 5 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety.) 【Chemistry 13】 (In the formula, * represents a bonding site to an oxygen atom, R B is a divalent organic group having 1 to 10 carbon atoms, and R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms.) 【Chemistry 14】 (* represents a bond.) 【Chemistry 15】 (wherein W 1 , W 2 , Y and n 1 are the same as defined above.) 【Chemistry 16】 (In the formula, m 3 and m 4 represent 1 or 2, Z is a single bond or a structure represented by the following general formula (5), and R x is a structure represented by the following general formula (6).) 【Chemistry 17】 (In the formula, * represents a bond, 1 represents an integer of 0 to 3, and R a to R f each independently represent a hydrogen atom or an optionally fluorine-substituted alkyl group having 1 to 10 carbon atoms, a phenyl group, or a phenylethyl group.) 【Chemistry 18】 (In the formula, * represents the bonding site to the aromatic ring, and Q 1 is a linear saturated hydrocarbon group having 1 to 30 carbon atoms or a structure represented by the following general formula (7).) 【Chemistry 19】 (In the formula, * represents a bonding site to a carbonyl group, R i is a hydrogen atom or an organic group represented by the general formula (2), and when the ratio of hydrogen atoms in the structure constituting R i is e and the ratio of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. R j represents a linear or branched hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, a nitro group, an amino group, a nitrile group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or an alkanoyloxy group having 1 to 10 carbon atoms. n 3 and n 4 represent the number of substituents on the aromatic ring and each represents an integer of 0 to 7, with the proviso that n 3 +n 4 is 0 to 7. n 5 represents 0 to 2.) 【Chemistry 20】 (In the formula, R 1 is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms; X is a divalent organic group having 1 to 30 carbon atoms; R a is a hydrogen atom or an organic group represented by the general formula (2); when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied; p is an integer of 0 to 5; q 1 is an integer of 1 to 6; p+q 1 is an integer of 1 or more and 6 or less; and q 2 is 0.)

10. A method for forming a protective film on a peripheral edge of a substrate to be processed and forming a pattern on the substrate to be processed, comprising: (II-1) A step of applying a protective film-forming composition to the peripheral edge of a substrate to be processed, the protective film-forming composition including a resin (A) having at least one structural unit represented by the following general formulas (A-1), (A-2), (A-3), (A-4), and (A-5), and a solvent; (II-2) A step of curing the applied protective film-forming composition by heat treatment or light irradiation to form a protective film on the peripheral edge of the substrate to be processed; (II-3) forming a resist upper layer film pattern on the substrate to be processed, and using the resist upper layer film pattern as a mask to form a pattern on the substrate to be processed by dry etching; (II-4) removing the protective film; A pattern forming method comprising the steps of: 【Chemical 21】 (In the formula, W 1 and W 2 each independently represent a benzene ring or a naphthalene ring, and hydrogen atoms in the benzene ring and naphthalene ring may be substituted with a hydrocarbon group having 1 to 6 carbon atoms. R a is a hydrogen atom or an organic group represented by the following general formula (2), and when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. Y is a group represented by the following general formula (3), n 1 is 0 or 1, n 2 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety.) 【Chemical 22】 (In the formula, Z 1 is a group represented by the following general formula (4), R a is a hydrogen atom or an organic group represented by the following general formula (2), and when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. n 4 is 0 or 1, n 5 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety.) 【Chemical 23】 (In the formula, * represents a bonding site to an oxygen atom, R B is a divalent organic group having 1 to 10 carbon atoms, and R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms.) 【Chemistry 24】 (* represents a bond.) 【Chemistry 25】 (wherein W 1 , W 2 , Y and n 1 are the same as defined above.) 【Chemical 26】 (In the formula, m 3 and m 4 represent 1 or 2, Z is a single bond or a structure represented by the following general formula (5), and R x is a structure represented by the following general formula (6).) 【Chemical 27】 (In the formula, * represents a bond, 1 represents an integer of 0 to 3, and R a to R f each independently represent a hydrogen atom or an optionally fluorine-substituted alkyl group having 1 to 10 carbon atoms, a phenyl group, or a phenylethyl group.) 【Chemical formula 28】 (In the formula, * represents the bonding site to the aromatic ring, and Q 1 is a linear saturated hydrocarbon group having 1 to 30 carbon atoms or a structure represented by the following general formula (7).) 【Chemical Formula 29】 (In the formula, * represents a bonding site to a carbonyl group, R i is a hydrogen atom or an organic group represented by the general formula (2), and when the ratio of hydrogen atoms in the structure constituting R i is e and the ratio of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. R j represents a linear or branched hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, a nitro group, an amino group, a nitrile group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or an alkanoyloxy group having 1 to 10 carbon atoms. n 3 and n 4 represent the number of substituents on the aromatic ring and each represents an integer of 0 to 7, with the proviso that n 3 +n 4 is 0 to 7. n 5 represents 0 to 2.) 【Chemistry 30】 (In the formula, R 1 is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms; X is a divalent organic group having 1 to 30 carbon atoms; R a is a hydrogen atom or an organic group represented by the general formula (2); when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied; p is an integer of 0 to 5; q 1 is an integer of 1 to 6; p+q 1 is an integer of 1 or more and 6 or less; and q 2 is 0.)

11. The pattern forming method described in claim 9, characterized in that in step (I-1), the protective film forming composition is applied to the peripheral edge of the back side of the workpiece substrate in addition to the peripheral edge of the front side of the workpiece substrate, and in step (I-2), the protective film is also formed on the peripheral edge of the back side of the workpiece substrate.

12. A pattern forming method as described in Claim 10, characterized in that in step (II-1), the protective film forming composition is applied to the peripheral edge of the back side of the workpiece substrate in addition to the peripheral edge of the front side of the workpiece substrate, and thereby in step (II-2), the protective film is also formed on the peripheral edge of the back side of the workpiece substrate.

13. A protective film-forming composition for forming a protective film on a peripheral edge of a substrate, A composition for forming a wafer edge protective film, comprising a resin (A) having at least one structural unit represented by the following general formulas (A-1), (A-2), (A-3), (A-4), and (A-5), and a solvent: 【Chemical 31】 (In the formula, W 1 and W 2 each independently represent a benzene ring or a naphthalene ring, and hydrogen atoms in the benzene ring and naphthalene ring may be substituted with a hydrocarbon group having 1 to 6 carbon atoms. R a is a hydrogen atom or an organic group represented by the following general formula (2), and when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. Y is a group represented by the following general formula (3), n 1 is 0 or 1, n 2 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety.) 【Chemical 32】 (In the formula, Z 1 is a group represented by the following general formula (4), R a is a hydrogen atom or an organic group represented by the following general formula (2), and when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. n 4 is 0 or 1, n 5 is 1 or 2, and each V independently represents a hydrogen atom or a linking moiety.) 【Chemical 33】 (In the formula, * represents a bonding site to an oxygen atom, R B is a divalent organic group having 1 to 10 carbon atoms, and R A is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms.) 【Chemical Formula 34】 (* represents a bond.) 【Chemistry 35】 (wherein W 1 , W 2 , Y and n 1 are the same as defined above.) 【Chemical 36】 (In the formula, m 3 and m 4 represent 1 or 2, Z is a single bond or a structure represented by the following general formula (5), and R x is a structure represented by the following general formula (6).) 【Chemical 37】 (In the formula, * represents a bond, 1 represents an integer of 0 to 3, and R a to R f each independently represent a hydrogen atom or an optionally fluorine-substituted alkyl group having 1 to 10 carbon atoms, a phenyl group, or a phenylethyl group.) 【Chemical 38】 (In the formula, * represents the bonding site to the aromatic ring, and Q 1 is a linear saturated hydrocarbon group having 1 to 30 carbon atoms or a structure represented by the following general formula (7).) 【Chemical 39】 (In the formula, * represents a bonding site to a carbonyl group, R i is a hydrogen atom or an organic group represented by the general formula (2), and when the ratio of hydrogen atoms in the structure constituting R i is e and the ratio of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied. R j represents a linear or branched hydrocarbon group having 1 to 10 carbon atoms, a halogen atom, a nitro group, an amino group, a nitrile group, an alkoxycarbonyl group having 1 to 10 carbon atoms, or an alkanoyloxy group having 1 to 10 carbon atoms. n 3 and n 4 represent the number of substituents on the aromatic ring and each represents an integer of 0 to 7, with the proviso that n 3 +n 4 is 0 to 7. n 5 represents 0 to 2.) 【Chemistry 40】 (In the formula, R 1 is a saturated monovalent organic group having 1 to 30 carbon atoms or an unsaturated monovalent organic group having 2 to 30 carbon atoms; X is a divalent organic group having 1 to 30 carbon atoms; R a is a hydrogen atom or an organic group represented by the general formula (2); when the proportion of hydrogen atoms in the structure constituting R a is e and the proportion of organic groups represented by the general formula (2) is f, the relationship e+f=1, 0.1≦f≦0.9 is satisfied; p is an integer of 0 to 5; q 1 is an integer of 1 to 6; p+q 1 is an integer of 1 or more and 6 or less; and q 2 is 0.)

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