Wafer processing method

Abstract

To provide a method for detecting impurities on the surface of silicon wafers for semiconductor manufacturing that cannot be detected by conventional inspection methods, a method for manufacturing semiconductor wafers with impurities removed from the wafer surface, and a method for selecting semiconductor wafers.SOLUTION: A method for detecting impurities on the surface of wafers for semiconductor manufacturing includes a process for forming a film by coating a film forming composition onto a wafer surface and baking it, and a process for detecting impurities in a wafer inspection system.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present application relates to a wafer processing method, such as a method for detecting impurities on the surface of a silicon wafer used in semiconductor manufacturing, a method for manufacturing a wafer used in semiconductor manufacturing from which impurities have been removed from the wafer surface, and a method for sorting wafers used in semiconductor manufacturing. [Background technology]

[0002] Wafers made from materials such as silicon used in semiconductor manufacturing are required to have as few impurities as possible, such as surface foreign matter.

[0003] Patent Document 1 describes a foreign matter detection method that uses a reflective specimen in which a photoresist coating is formed on a semiconductor substrate such as a silicon substrate, and can reliably detect foreign matter buried inside this photoresist coating. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-20961 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a method for detecting impurities on the surface of silicon wafers for semiconductor manufacturing that cannot be detected by conventional inspection methods, a method for manufacturing wafers for semiconductor manufacturing from which impurities on the wafer surface have been removed, and a method for selecting wafers for semiconductor manufacturing. [Means for solving the problem]

[0006] The present invention encompasses the following.

[0007] [1] A method for detecting impurities on a surface of a semiconductor manufacturing wafer, comprising: A method for detecting impurities on the surface of a wafer used in semiconductor manufacturing, comprising the steps of applying a film-forming composition to the surface of the wafer and baking the composition to form a film, and then detecting the impurities using a wafer inspection device.

[0008] [2] The impurity detection method according to [1], wherein the impurity contains a fluorine atom.

[0009] [3] The impurity detection method according to [1] or [2], wherein the film-forming composition contains a resin.

[0010] [4] The impurity detection method according to any one of [1] to [3], wherein the film-forming composition is a coating film-forming composition for lithography.

[0011] [5] The impurity detection method according to any one of [1] to [4], wherein the film-forming composition is a resist underlayer film-forming composition.

[0012] [6] A method for manufacturing a semiconductor wafer from which impurities on the wafer surface have been removed, comprising: A step (A) of heating a crude semiconductor manufacturing wafer (I) to 100 ° C to 500 ° C and / or a step (A) of washing with ultrapure water; a step (B) of inspecting the semiconductor manufacturing wafer (II) that has undergone the step (A) by the impurity detection method according to any one of [1] to [5]; a step (C) of selecting a semiconductor manufacturing wafer (IV) from the semiconductor manufacturing wafers (III) that have been subjected to the step (B), the number of defects present on the surface of which has been reduced by 80% or more compared to the crude semiconductor manufacturing wafer (I); A method for manufacturing a wafer for semiconductor manufacturing, in which impurities on the wafer surface have been removed, comprising:

[0013] [7] A method for sorting wafers for semiconductor manufacturing, comprising: A step (A) of heating a crude semiconductor manufacturing wafer (I) to 100 ° C to 500 ° C and / or a step (A) of washing with ultrapure water; a step (B) of inspecting the semiconductor manufacturing wafer that has been subjected to the step (A) by the impurity detection method according to any one of [1] to [5]; a step (C) of selecting a semiconductor manufacturing wafer (IV) from the semiconductor manufacturing wafers (III) that have been subjected to the step (B), the number of defects present on the surface of which has been reduced by 80% or more compared to the crude semiconductor manufacturing wafer; Including, The step (C) includes dividing the semiconductor manufacturing wafers (III) that have been subjected to the step (B) into semiconductor manufacturing wafers (IV) in which the number of defects present on their surfaces has been reduced by 80% or more compared to the crude semiconductor manufacturing wafers (I) and semiconductor manufacturing wafers (V) in which the number of defects present on their surfaces has been reduced by less than 80% compared to the crude semiconductor manufacturing wafers (I), and selecting the semiconductor manufacturing wafers (IV). A method for sorting wafers for semiconductor manufacturing. [Effects of the Invention]

[0014] The method of the present application makes it possible to detect impurities present on the surface of semiconductor manufacturing wafers that would otherwise be removed by heating and / or ultrapure water cleaning. These impurities may include fluorine atoms. This detection method makes it possible to manufacture and select semiconductor manufacturing wafers (so-called bare wafers) from which impurities that would otherwise be undetectable have been removed. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram showing the distribution of defects in the silicon wafers obtained in Examples 1 and 2 and Reference Examples 1 to 5. [Figure 2] 1 is a graph showing an SEM photograph illustrating the shape of a defect in Example 1 and the results of composition analysis. [Figure 3] 10 is a graph showing an SEM photograph illustrating the shape of a defect in Example 2 and the results of composition analysis. [Figure 4] 1 is a schematic diagram of the defect distribution in the silicon wafers obtained in Examples 3 to 5 and Comparative Examples 1 and 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] <Method for detecting impurities on the surface of semiconductor wafers> The method for detecting impurities on the surface of a wafer for semiconductor manufacturing according to the present invention comprises: The method includes a step of applying a film-forming composition to the wafer surface and baking it to form a film, and then a step of detecting impurities using a wafer inspection device.

[0017] The impurities may include fluorine atoms.

[0018] Wafers for semiconductor manufacturing are wafers used to manufacture semiconductor devices and the like, and include commonly used silicon wafers and germanium wafers, as well as compound semiconductor wafers formed by combining two or more elements, such as gallium arsenide, indium phosphide, gallium nitride, indium nitride, and aluminum nitride. They are usually disk-shaped and come in sizes such as 4, 6, 8, and 12 inches. Commercially available products may be used.

[0019] A film-forming composition (organic film-forming composition, inorganic film-forming composition) described below is applied onto the semiconductor wafer by a suitable application method such as a spinner or coater. Then, a film (organic film, inorganic film) is formed by baking using a heating means such as a hot plate. Baking conditions are appropriately selected from a bake temperature of 100°C to 400°C and a bake time of 0.3 to 60 minutes. Preferably, the bake temperature is 120°C to 400°C, the bake temperature is 120°C to 350°C, and the bake time is 0.5 to 30 minutes, and more preferably, the bake temperature is 150°C to 300°C, and the bake time is 0.8 to 10 minutes. The thickness of the formed film is 0.01 μm (10 nm) to 2 μm (2,000 nm), 0.02 μm (20 nm) to 1 μm (1,000 nm), 0.025 μm (25 nm) to 1 μm (1,000 nm), 0.02 μm (20 nm) to 0.9 μm (900 nm), 0.025 μm (25 nm) to 0.9 μm (900 nm), 0.02 μm (20 nm) to 0.8 μm (800 nm), or 0.025 μm (25 nm) to 0.8 μm (800 nm). This film thickness is preferably uniform across the wafer (for example, within ±20%, ±10%, ±5%, ±3%, or ±1% of the median film thickness).

[0020] A commercially available wafer inspection device may be used, such as the Surfscan series wafer inspection system manufactured by KLA-Tencor Corporation.

[0021] <Film forming composition> The film-forming composition used in the present application is not particularly limited as long as it is a composition that can form the above-mentioned film thickness uniformly. Either an organic film-forming composition or an inorganic film-forming composition may be used, but it is preferable to use a coating film-forming composition for lithography used in a lithography process during the manufacture of a semiconductor device, which has a film containing few impurities to the extent that it is possible to use the impurity detection method, semiconductor manufacturing method, and semiconductor manufacturing wafer sorting method of the present application, and which can form a film with a uniform thickness within the wafer surface.

[0022] The film-forming composition preferably contains a resin. The resin is also called a polymer, a copolymer, a high molecular weight compound, etc. The resin in the present application may be either an organic resin or an inorganic resin (e.g., a hydrolysis condensation product of a silane compound, polysiloxane, etc.).

[0023] Examples of the coating film-forming composition for lithography used in the present application include, but are not limited to, the following known photoresist compositions, known resist underlayer film-forming compositions (containing an organic compound and / or an inorganic compound), known protective film-forming compositions for protecting a substrate from an etching solution during semiconductor substrate processing, known underlayer film-forming compositions for self-assembled films, known overlayer film-forming compositions for self-assembled films, and known resist overlayer film-forming compositions.

[0024] The exposure wavelength in the lithography step may be i-line, KrF excimer laser, ArF excimer laser, EUV (extreme ultraviolet), or EB (electron beam). The coating film-forming composition for lithography is preferably compatible with these exposure wavelengths.

[0025] Specific examples of coating film-forming compositions for lithography include resist upper layer film-forming compositions for resist upper layer films described in WO 2014 / 115843, WO 2015 / 129486, etc.; underlayer film-forming compositions for self-assembled films utilizing block copolymer self-assembly (DSA, Direct Self Assembly) technology described in WO 2013 / 146600, WO 2014 / 097993, etc.; for example, upper layer film-forming compositions for the self-assembled films described in WO 2018 / 051907; and coating compositions for pattern reversal described in WO 2016 / 031563 and WO 2017 / 145809.

[0026] Other specific examples of coating film-forming compositions for lithography include those described in WO 2009 / 096340, JP 2009-053704 A, WO 2010 / 147155, WO 2011 / 102470, WO 2011 / 021555, WO 2013 / 047516, WO 2015 / 030060, WO 2018 / 052130, WO 2019 / 047517, WO 2019 / 047518, WO 2019 / 047519, WO 2020 / 047519, WO 2021 / 047519, WO 2022 / 047519, WO 2023 / 047519, WO 2024 / 047519, WO 2025 / 047519, WO 2026 / 047519, WO 2027 / 047519, WO 2028 / 047519, WO 2029 / 047519, WO 2030 / 047519, WO 2031 / 047519, WO 2032 / 047519, WO 2033 / 047519, WO 2034 / 047519, WO 2035 / 047519, WO 2036 / 047519, WO 2037 / 047519, WO 2038 / 047519, WO 2039 / 047519, WO 2040 / 047519, WO 2041 / 04751 The protective film-forming composition, resist underlayer-forming composition, and silicon-containing resist underlayer film-forming composition may be those described in Publication No. 2019 / 124474, International Publication No. 2019 / 124475, International Publication No. 2019 / 151471, International Publication No. 2019 / 163834, PCT / JP2019 / 042708, PCT / JP2020 / 001627, PCT / JP2020 / 018436, etc.

[0027] The solids content of the coating film-forming composition for lithography according to the present invention is typically 0.1 to 70% by mass, preferably 0.1 to 60% by mass, and more preferably 0.1 to 40% by mass. The solids content refers to the content of all components in the coating film-forming composition for lithography excluding the solvent. The proportion of polymer in the solids content is, for example, 30 to 100% by mass, 50 to 100% by mass, 60 to 100% by mass, 70 to 100% by mass, 80 to 100% by mass, 60 to 99.9% by mass, 60 to 99% by mass, 60 to 98% by mass, 60 to 97% by mass, 60 to 96% by mass, 60 to 95% by mass, 70 to 99.9% by mass, 70 to 99% by mass, 70 to 98% by mass, 70 to 97% by mass, 70 to 96% by mass, or 70 to 95% by mass.

[0028] Among these, a resist underlayer film-forming composition is preferred, and a specific example is a resist underlayer film-forming composition containing a triaryldiamine-containing novolak resin to which an aromatic vinyl compound is added, as described in WO 2019 / 163834. This resist underlayer film-forming composition contains a novolak resin containing a structural group (C) formed by reaction of an aromatic ring of an aromatic compound (A) containing at least two amino groups and three aromatic rings having 6 to 40 carbon atoms with a vinyl group of an aromatic vinyl compound (B).

[0029] The structural group (C) is represented by the following formula (1): [ka] [In formula (1), R 1 is a divalent group containing at least two amino groups and at least three aromatic rings having 6 to 40 carbon atoms, R 2 and R 3are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, a heterocyclic group, or a combination thereof, and the alkyl group, the aryl group, and the heterocyclic group are organic groups which may be substituted with a halogen atom, a nitro group, an amino group, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, a formyl group, a carboxyl group, an alkoxy group, or a hydroxy group, and R 2 and R 3 may form a ring together with the carbon atom to which they are attached, T 1 is an arylene group having 6 to 40 carbon atoms, T 3 represents an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, a hydroxy group, a cyano group, a nitro group, an amino group, a carboxyl group, an acetyl group, a hydroxymethyl group, a halogenomethyl group, a -YZ group, a halogen atom, or a combination thereof. Y represents an oxygen atom, a sulfur atom, a carbonyl group, or an ester group, and Z represents an alkyl group having 1 to 10 carbon atoms.

[0030] T 2 represents a hydrogen atom, a methyl group, or a phenyl group.

[0031] m is an integer between 0 and (5+2n), n is T 1 represents the degree of condensation of aromatic rings constituting the arylene group, which is the definition of m1 is an integer of 2 to 3600.] is preferable.

[0032] R 1 is expressed by the following formula (2): [ka] [In formula (2), Ar 1 , Ar 2 , and Ar 3 each independently represents a benzene ring or a naphthalene ring, R 6 , R 7 , and R 8 are each independently a substituent on these rings, and are selected from the group consisting of a halogen atom, a nitro group, an amino group, a hydroxy group, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and combinations thereof, and the alkyl group, the alkenyl group, and the aryl group represent an organic group which may contain an ether bond, a ketone bond, or an ester bond; R 4 and R 5 are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, and combinations thereof, and the alkyl group, the alkenyl group, and the aryl group represent an organic group which may contain an ether bond, a ketone bond, or an ester bond; n1, n2, and n3 are each 0 or greater, and R 6 , R 7 , and R 8 is an integer up to the maximum number of substitutions.] is preferably a divalent organic group obtained by removing two hydrogen atoms from the aromatic ring of a compound represented by the formula:

[0033] The structural group (C) is represented by the following formula (1-1): [ka] [In formula (1-1), R 2 and R 3 are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, a heterocyclic group, or a combination thereof, and the alkyl group, the aryl group, and the heterocyclic group are organic groups which may be substituted with a halogen atom, a nitro group, an amino group, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms, a formyl group, a carboxyl group, an alkoxy group, or a hydroxy group, and R 2 and R 3may form a ring together with the carbon atom to which they are attached.

[0034] T 2 represents a hydrogen atom, a methyl group, or a phenyl group; m1 is an integer of 2 to 3600.] is preferable.

[0035] The entire disclosure of International Publication No. 2019 / 163834 is incorporated herein by reference.

[0036] The resist underlayer film-forming composition is preferably a resist underlayer film-forming composition for lithography containing a resin containing an aliphatic ring and an aromatic ring, as described in International Publication No. 2011 / 021555. This resist underlayer film-forming composition for lithography is a resist underlayer film-forming composition containing an alicyclic epoxy polymer (A') and a reaction product (C') of a fused-ring aromatic carboxylic acid and a monocyclic aromatic carboxylic acid (B').

[0037] The above (A') is represented by formula (11): [ka] (in formula (11), T represents a repeating unit structure having an aliphatic ring in the main chain of the polymer, and E represents an epoxy group or an organic group having an epoxy group).

[0038] The above (C') is represented by formula (12): [ka] (in formula (12), T represents a repeating unit structure having an aliphatic ring in the main chain of the polymer, Q represents a linking group connecting T to the aromatic fused ring and the aromatic monocycle, and Ar represents the aromatic fused ring and the aromatic monocycle).

[0039] The reaction product (C') is represented by the following formulas (13), (14), and (15): [ka] When the total number of unit structures contained in the reaction product (C') is taken as 1.0, the number a of repeating unit structures of formula (13), the number b of repeating unit structures of formula (14), and the number c of repeating unit structures of formula (15) preferably satisfy the following relationships: 0≦a≦0.2, 0.3≦b≦0.7, 0.3≦c≦0.7, and 0.5≦b+c≦1.0.

[0040] The entire disclosure of International Publication No. 2011 / 021555 is incorporated herein by reference.

[0041] An example of a specific structure of a suitable resin (polymer) is the following formula (21):

[0042] [ka] [In the above formula (21), X is the following formula (22), formula (23), or formula (24): [ka] (In the above formulas (22), (23), and (24), R 1 ~R 5 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a benzyl group, or a phenyl group, and the phenyl group may be substituted with at least one group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and an alkylthio group having 1 to 6 carbon atoms; and R 1 and R 2 , R 3 and R 4 may be bonded to each other to form a ring having 3 to 6 carbon atoms; A 1 ~A6 each independently represents a hydrogen atom, a methyl group, or an ethyl group; Q 1 represents a divalent group containing a disulfide bond, preferably a divalent group containing an alkylene group having 1 to 6 carbon atoms at each end of the disulfide bond, n is the number of repeating structural units and represents an integer of 5 to 100. It is preferable that the unit structure be represented by the following formula:

[0043] Examples of the resin (polymer) of the present application include, but are not limited to, the polymers described in WO 2009 / 096340 and reaction products of bifunctional or higher functional compounds having at least one disulfide bond and trifunctional or higher functional compounds described in WO 2019 / 151471.

[0044] When the polymer is a reaction product of a bifunctional compound (A") having at least one disulfide bond and a bifunctional compound (B") different from the compound (A"), the disulfide bond is present in the main chain of the polymer.

[0045] The polymer may have a repeating unit structure represented by the following formula (31): [ka] (In the above formula (31), R1 is an alkyl group having 0 to 1 carbon atoms, n is the number of repeating unit structures and represents an integer of 0 or 1, and m is an integer of 0 or 1. Z1 represents a group represented by the following formula (32), formula (33), or formula (34): [ka] In the above formula (33), X represents a group represented by the following formula (44), formula (45), or formula (46): [ka] In the above formulas (44), (45), and (46), R2~R 61 (R2, R3, R4, R 51 and R 61 ) each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 3 to 6 carbon atoms, a benzyl group, or a phenyl group, and the phenyl group may be substituted with at least one group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, a halogen atom, an alkoxy group having 1 to 6 carbon atoms, a nitro group, a cyano group, and an alkylthio group having 1 to 6 carbon atoms, and R2 and R3, and R4 and R5 may be bonded to each other to form a ring having 3 to 6 carbon atoms.

[0046] A1 to A6 each independently represent a hydrogen atom, a methyl group, or an ethyl group; Q1 represents an alkylene group having 1 to 10 carbon atoms interrupted by a disulfide bond; l is the number of repeating unit structures and represents an integer of 5 to 100. Q1 is preferably an alkylene group of 2 to 6 carbon atoms interrupted by a disulfide bond.

[0047] Examples of the "ring having 3 to 6 carbon atoms" include cyclopropane, cyclobutane, cyclopentane, cyclopentadiene, and cyclohexane.

[0048] The above formula (31) can be expressed by the following formula (55): [ka] [In the above formula (55), X represents a group represented by the above formula (44), formula (45), or formula (46), and R 6 and R 7 each independently represents an alkylene group having 1 to 3 carbon atoms or a direct bond, p is the number of repeating unit structures and represents an integer of 5 to 100. It may be expressed as:

[0049] The polymer is preferably represented by the following formulas P-6 to P-8.

[0050] [ka] [ka] [ka] The resin (polymer) is preferably a reaction product synthesized by reacting a bifunctional or higher functional compound (A") having at least one disulfide bond with a bifunctional or higher functional compound (B") by a method known per se.

[0051] The entire disclosures of WO 2009 / 096340 and WO 2019 / 151471 are incorporated herein by reference.

[0052] <Crosslinking agent> Examples of crosslinking agents that may be optionally included in the film-forming composition of the present invention include hexamethoxymethylmelamine, tetramethoxymethylbenzoguanamine, 1,3,4,6-tetrakis(methoxymethyl)glycoluril (tetramethoxymethylglycoluril) (POWDERLINK® 1174), 1,3,4,6-tetrakis(butoxymethyl)glycoluril, 1,3,4,6-tetrakis(hydroxymethyl)glycoluril, 1,3-bis(hydroxymethyl)urea, 1,1,3,3-tetrakis(butoxymethyl)urea, 1,1,3,3-tetrakis(methoxymethyl)urea, and 2,4,6-tris[bis(methoxymethyl)amino]-1,3,5-triazine ((trade name) Cymel®-303, Nikalac® MW-390).

[0053] The crosslinking agent may be a compound represented by the following formula (71) or (72):

[0054] [ka]

[0055] (In equations (71) and (72), Q 1 represents a single bond or a monovalent organic group, and R 1 and R 4 each represents an alkyl group having 2 to 10 carbon atoms or an alkyl group having 2 to 10 carbon atoms and an alkoxy group having 1 to 10 carbon atoms; R 2 and R 5 each represents a hydrogen atom or a methyl group, and R 3 and R 6 respectively represent an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms. n1 is an integer satisfying 1≦n1≦3, n2 is an integer satisfying 2≦n2≦5, n3 is an integer satisfying 0≦n3≦3, n4 is an integer satisfying 0≦n4≦3, and 3≦(n1+n2+n3+n4)≦6. n5 is an integer of 1≦n5≦3, n6 is an integer of 1≦n6≦4, n7 is an integer of 0≦n7≦3, n8 is an integer of 0≦n8≦3, and 2≦(n5+n6+n7+n8)≦5. m1 is an integer of 2 to 10. The crosslinkable compound represented by the above formula (71) or formula (72) may be obtained by reacting a compound represented by the following formula (73) or formula (74) with a hydroxyl group-containing ether compound or an alcohol having 2 to 10 carbon atoms.

[0056] [ka]

[0057] (In equations (73) and (74), Q 2 represents a single bond or a divalent organic group. 8 , R 9 , R 11 and R 12 each represents a hydrogen atom or a methyl group, and R 7 and R 10respectively represent an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms. n9 is an integer in the range of 1≦n9≦3, n10 is an integer in the range of 2≦n10≦5, n11 is an integer in the range of 0≦n11≦3, n12 is an integer in the range of 0≦n12≦3, and 3≦(n9+n10+n11+n12)≦6. n13 is an integer of 1≦n13≦3, n14 is an integer of 1≦n14≦4, n15 is an integer of 0≦n15≦3, n16 is an integer of 0≦n16≦3, and 2≦(n13+n14+n15+n16)≦5. m2 is an integer of 2 to 10. The reaction of a compound represented by the following formula (73) or (74) with a hydroxyl group-containing ether compound or an alcohol having 2 to 10 carbon atoms may be carried out in the presence of an acid catalyst. Examples of the crosslinkable compounds represented by formula (71) and formula (72) used in the present invention include the following.

[0058] [ka]

[0059] [ka]

[0060] [ka]

[0061] [ka]

[0062] [ka]

[0063] The compounds represented by formula (73) and formula (74) used in the present invention can be exemplified as follows.

[0064] [ka]

[0065] [ka]

[0066] The entire disclosure of WO 2014 / 208542 is incorporated herein by reference.

[0067] The crosslinking agent may also be a nitrogen-containing compound having, per molecule, 2 to 6 substituents bonded to nitrogen atoms and represented by the following formula (61), as described in WO 2017 / 187969:

[0068] [ka] (In formula (61), R1 represents a methyl group or an ethyl group.) The nitrogen-containing compound having 2 to 6 substituents represented by the formula (61) in one molecule may be a glycoluril derivative represented by the following formula (1A).

[0069] [ka] (In formula (1A), four R1s each independently represent a methyl group or an ethyl group, and R2 and R3 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group.) Examples of the glycoluril derivative represented by the formula (1A) include compounds represented by the following formulae (1A-1) to (1A-6).

[0070] [ka] The compound represented by the formula (1A) can be obtained by reacting a nitrogen-containing compound having 2 to 6 substituents bonded to a nitrogen atom and represented by the following formula (62) in one molecule with at least one compound represented by the following formula (63) to produce a nitrogen-containing compound having 2 to 6 substituents represented by the formula (61) in one molecule. [ka] (In the formulas (62) and (63), R1 represents a methyl group or an ethyl group, and R4 represents an alkyl group having 1 to 4 carbon atoms.) The glycoluril derivative represented by the formula (1A) can be obtained by reacting a glycoluril derivative represented by the following formula (2A) with at least one compound represented by the formula (63).

[0071] The nitrogen-containing compound having 2 to 6 substituents represented by the formula (62) in one molecule is, for example, a glycoluril derivative represented by the following formula (2A). [ka] (In formula (2A), R2 and R3 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, and R4 each independently represent an alkyl group having 1 to 4 carbon atoms.) Examples of glycoluril derivatives represented by the formula (2A) include compounds represented by the following formulae (2A-1) to (2A-4): Furthermore, examples of compounds represented by the formula (63) include compounds represented by the following formulae (2A-5) and (2A-6): [ka] [ka] The entire disclosure of WO 2017 / 187969 is incorporated herein by reference with respect to the content of a nitrogen-containing compound having 2 to 6 substituents bonded to the nitrogen atom and represented by formula (61) per molecule.

[0072] When the crosslinking agent is used, the content of the crosslinking agent is, for example, 1% by mass to 50% by mass, and preferably 5% by mass to 30% by mass, relative to the organic resin.

[0073] <Method for manufacturing semiconductor wafers> The method for producing a semiconductor manufacturing wafer of the present application, from which impurities have been removed from the wafer surface, includes the steps of: (A) heating a crude semiconductor manufacturing wafer (I) to 100°C to 500°C and / or washing the wafer with ultrapure water; (B) inspecting the semiconductor manufacturing wafer (II) that has undergone the step (A) using the impurity detection method; and (C) selecting, from the semiconductor manufacturing wafers (III) that have undergone the step (B), a semiconductor manufacturing wafer (IV) in which the number of defects present on its surface has been reduced by 80% or more compared to the crude semiconductor manufacturing wafer.

[0074] The crude semiconductor manufacturing wafer (I) refers to an untreated semiconductor manufacturing wafer before the semiconductor manufacturing wafer is subjected to a heating step and / or a step of cleaning with ultrapure water.

[0075] In step (A), the wafer is heated at a temperature in the range of 100°C to 500°C, preferably 120°C to 500°C, 120°C to 400°C, 150°C to 400°C, 200°C to 400°C, 200°C to 500°C, or 300°C to 500°C. The heating time is usually 0.5 to 30 minutes. The heating is usually performed in the atmosphere, but may also be performed in an inert gas atmosphere such as a nitrogen atmosphere. The method for cleaning the wafer with ultrapure water is not particularly limited, but examples include batch cleaning and single-wafer cleaning. The temperature of the ultrapure water is, for example, 5°C to 50°C, and the cleaning time is, for example, 1 minute to 1 hour. This may be performed in combination with ultrasonic cleaning. The heating step and the ultrapure water cleaning step may also be performed in combination. Either order is not important.

[0076] <Sorting method for wafers used in semiconductor manufacturing> The method for selecting wafers for semiconductor production of the present application includes a step (A) of heating crude semiconductor production wafers (I) to 100°C to 500°C and / or a step (B) of cleaning the crude semiconductor production wafers (I) with ultrapure water, a step (B) of inspecting the crude semiconductor production wafers (II) that have undergone the step (A) using the impurity detection method, and a step (C) of selecting, from the crude semiconductor production wafers (III) that have undergone the step (B), wafers for semiconductor production (IV) that have a number of defects present on their surfaces that is reduced by 80% or more compared to the crude semiconductor production wafers (I).

[0077] Step (C) can include, for example, separating the semiconductor manufacturing wafers (III) that have been subjected to step (B) into semiconductor manufacturing wafers (IV) having a number of defects present on their surfaces reduced by 80% or more compared to the crude semiconductor manufacturing wafers (I) and semiconductor manufacturing wafers (V) having a number of defects reduced by less than 80% compared to the crude semiconductor manufacturing wafers (I), and selecting the semiconductor manufacturing wafers (IV).

[0078] The explanation of the terms used in this section is the same as that in the above <Method for manufacturing wafers for semiconductor manufacturing>. [Example]

[0079] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

[0080] <Synthesis Example 1> N,N'-diphenyl-1,4-phenylenediamine (41.98 g, 0.161 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), 4-amyloxybenzaldehyde (31.02 g, 0.161 mol, manufactured by Tokyo Chemical Industry Co., Ltd.), 4-(tert-butoxy)styrene (94.75 g, 0.537 mol, manufactured by Wako Pure Chemical Industries, Ltd.), and propylene glycol monomethyl ether (172.37 g, manufactured by Kanto Chemical Co., Inc.) were charged into a 300 mL four-neck flask, and methanesulfonic acid (4.65 g, 0.048 mol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added and stirred. The mixture was heated to 135°C to dissolve the components and initiate polymerization. After 18 hours, the mixture was allowed to cool to room temperature and then reprecipitated using a mixed solvent of methanol (1000 g, manufactured by Kanto Chemical Co., Inc.), 1000 g of ultrapure water, and 30% aqueous ammonia (100 g, manufactured by Kanto Chemical Co., Inc.). The resulting precipitate was filtered and dried in a vacuum dryer at 80°C for 24 hours to obtain 136.68 g of the target polymer represented by formula (a). The weight-average molecular weight (Mw) measured in terms of polystyrene was 1400, and the polydispersity (Mw / Mn) was 1.29.

[0081] [ka]

[0082] <Synthesis Example 2> 40.0 g of the compound of formula (b-1) (manufactured by Daicel Chemical Industries, Ltd., trade name: EHPE3150), 20.3 g of 9-anthracenecarboxylic acid, and 13.7 g of benzoic acid were dissolved in 302.0 g of propylene glycol monomethyl ether, and then 1.5 g of benzyltriethylammonium was added and the mixture was refluxed for 24 hours to react. After the reaction, the solution was purified using an ion exchange method to obtain a polymer solution of formula (b-2). GPC analysis of the obtained polymer revealed that the weight average molecular weight, calculated as standard polystyrene, was 4100.

[0083] [ka] [ka]

[0084] <Synthesis Example 3> 800 g of monoallyl diglycidyl isocyanuric acid (manufactured by Shikoku Chemical Industry Co., Ltd.), 608 g of 3,3'-dithiodipropionic acid (manufactured by Sakai Chemical Industry Co., Ltd., trade name: DTDPA), and 53 g of triphenyl monoethyl phosphonium bromide, a quaternary phosphonium salt, as a catalyst were dissolved in 2191 g of propylene glycol monomethyl ether, heated, and stirred for 4 hours under a nitrogen atmosphere while maintaining the temperature at 120°C. The resulting reaction product was diluted with 3652 g of propylene glycol monomethyl ether to form a varnish solution, which was subjected to GPC analysis. The weight-average molecular weight, calculated as standard polystyrene, was approximately 7800. This reaction product contains a polymer compound having a structural unit represented by the following formula (c-1):

[0085] [ka]

[0086] <Preparation Example 1> To 17.64 g of the polymer synthesized in Synthesis Example 1 above, 3.53 g of the compound represented by formula (d-2), abbreviated as PGME-BIP-A, which is a compound obtained by dehydration condensation of each of the four methylol groups of 2,2-bis[3,5-bis[(2-methoxy-1-methylethoxy)methyl]-4-hydroxyphenyl]propane represented by formula (d-1) with propylene glycol monomethyl ether, was added as a crosslinking agent, 0.58 g of pyridinium-p-phenolsulfonate as a crosslinking catalyst, 0.02 g of Megafac (trade name) R-30N manufactured by DIC Corporation as a surfactant, and 23.47 g of propylene glycol monomethyl ether and 54.76 g of propylene glycol monomethyl ether acetate as solvents, to prepare a resist underlayer film-forming composition.

[0087] [ka] [ka]

[0088] <Preparation Example 2> To 31.49 g of the polymer solution obtained in Synthesis Example 2 (polymer solids content: 16% by mass), 1.26 g of tetramethoxymethyl glycoluril (POWDERLINK (registered trademark) 1174) manufactured by Nippon Cytec Industries Co., Ltd. as a crosslinking agent, 0.04 g of pyridinium-p-toluenesulfonate as a crosslinking catalyst, 0.004 g of Megafac (trade name) R-30N manufactured by DIC Corporation as a surfactant, and 57.63 g of propylene glycol monomethyl ether and 9.58 g of propylene glycol monomethyl ether acetate as solvents were added to prepare a resist underlayer film-forming composition.

[0089] <Preparation Example 3> To 3.58 g of the polymer solution obtained in Synthesis Example 2 (polymer solids content: 20% by mass), 0.18 g of tetramethoxymethyl glycoluril (POWDERLINK (registered trademark) 1174) manufactured by Nippon Cytec Industries Co., Ltd., 0.02 g of 4-hydroxybenzenesulfonic acid (PSA) as a crosslinking catalyst, 0.01 g of bisphenol S as an additive, 0.01 g of Megafac (trade name) R-30N manufactured by DIC Corporation as a surfactant, 86.30 g of propylene glycol monomethyl ether, and 9.91 g of propylene glycol monomethyl ether acetate were added to prepare a resist underlayer film-forming composition.

[0090] Example 1 The resist underlayer film-forming composition obtained in Preparation Example 1 was applied onto a 12-inch silicon wafer using a CLEAN TRACK Lithius Pro AP coater manufactured by Tokyo Electron Co., Ltd. The coated film was baked at 240°C for 60 seconds and then further baked at 400°C for 60 seconds to obtain a 12-inch silicon wafer on which a coating film having a thickness of 800 nm was formed.

[0091] <Example 2> The resist underlayer film-forming composition obtained in Preparation Example 2 was applied onto a 12-inch silicon wafer using a coating device CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron Co., Ltd. The coated film was baked at 205°C for 60 seconds to obtain a 12-inch silicon wafer on which a coating film having a thickness of 200 nm was formed.

[0092] <Reference example 1> A 12-inch silicon wafer was baked at 400° C. for 60 seconds using a coating device, CLEAN TRACK Lithius Pro AP, manufactured by Tokyo Electron, to obtain a heat-treated 12-inch silicon wafer.

[0093] <Reference example 2> Propylene glycol monomethyl ether (PGME), a solvent used in the resist underlayer film-forming composition, was applied onto a 12-inch silicon wafer using a Tokyo Electron CLEAN TRACK Lithius Pro AP coating device. The coated film was baked at 205°C for 60 seconds to obtain a 12-inch silicon wafer with a coated film formed thereon.

[0094] <Reference example 3> A 12-inch silicon wafer was baked at 400°C for 60 seconds using a Tokyo Electron CLEAN TRACK Lithius Pro AP coating device. The resist underlayer film-forming composition obtained in Preparation Example 1 was coated onto the baked 12-inch silicon wafer. The coated film was baked at 240°C for 60 seconds and then further baked at 400°C for 60 seconds, yielding a 12-inch silicon wafer on which a coating film with a thickness of 800 nm was formed.

[0095] <Reference example 4> A 12-inch silicon wafer was baked at 205°C for 60 seconds using a Tokyo Electron CLEAN TRACK Lithius Pro AP coating device. The resist underlayer film-forming composition obtained in Preparation Example 2 was coated onto the baked 12-inch silicon wafer. The coated film was baked at 25°C for 60 seconds to obtain a 12-inch silicon wafer on which a coating film having a thickness of 200 nm was formed.

[0096] <Reference example 5> The resist underlayer film-forming composition obtained in Preparation Example 3 was applied onto a 12-inch silicon wafer using a coating device, CLEAN TRACK Lithius Pro AP, manufactured by Tokyo Electron Co., Ltd. The coated film was baked at 205°C for 60 seconds to obtain a 12-inch silicon wafer on which a coating film having a thickness of 25 nm was formed.

[0097] (Defect distribution on wafer) The silicon wafers obtained in Examples 1 and 2 were subjected to measurement of defects on the film surface using a wafer inspection system, Surfscan SP2XP, manufactured by KLA-Tencor Corporation. The defect distribution within the wafer is shown in Figure 1, and the number of defects is shown in Table 1. The shape and elemental analysis of the defects detected in Examples 1 and 2 were performed using a Defect Review SEM RS6000 manufactured by Hitachi High-Tech Corporation, and the results are shown in Figures 2 and 3.

[0098] [Table 1] In FIG. 1, Examples 1 and 2, in which the resist underlayer film-forming composition was applied to an untreated 12-inch silicon wafer, showed a characteristic distribution of defects on the outer periphery of the wafer.

[0099] In Reference Examples 3 and 4, in which a 12-inch silicon wafer was baked in advance and then coated with the resist underlayer film-forming composition, no characteristic distribution of defects was observed on the wafer periphery, and the number of defects was small. In addition, in Reference Example 1, in which a 12-inch silicon wafer was baked, and Reference Example 2, in which a solvent was coated, no characteristic distribution of defects was observed on the wafer periphery.

[0100] This indicates that impurities are present on the surface of 12-inch silicon wafers, that these impurities are components that are removed by baking, and that these impurities cannot be detected by baking the 12-inch silicon wafers directly or by coating them with a solvent that volatilizes after baking and does not remain on the wafer. On the other hand, Reference Example 5 indicates that the impurities cannot be detected in a coating film with a thickness of 25 nm, and that a coating film thickness of 25 nm or more is necessary.

[0101] From FIG. 2, it was confirmed that the shapes of the defects detected on the outer periphery of the wafer in Example 1 were all similar, and that elemental fluorine was characteristically detected.

[0102] In addition, as shown in Figure 3, all of the defects detected on the outer periphery of the wafer in Example 2 had similar shapes, confirming that elemental fluorine was characteristically detected. This indicated that the impurities contained fluorine. It was demonstrated that the fluorine-containing impurities present on a 12-inch silicon wafer could be detected by performing the treatments of Examples 1 and 2 and confining them on the wafer and the organic film formed from the resist underlayer film-forming composition.

[0103] Example 3 A 12-inch silicon wafer was baked at 205°C for 60 seconds using a coating apparatus CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron. The resist underlayer film-forming composition obtained in Preparation Example 2 was coated onto the baked wafer using a coating apparatus CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron. The coated film was baked in air at 205°C for 60 seconds to obtain a 12-inch silicon wafer on which a coating film having a thickness of 200 nm was formed.

[0104] Example 4 A 12-inch silicon wafer was rotated using a spin cleaner MSC-5000NC manufactured by Saneki Semiconductor Industrial Co., Ltd., while ultrapure water at 23°C was sprayed onto the wafer surface at 1.5 L / min for 60 seconds to clean the wafer surface. The resist underlayer film-forming composition obtained in Preparation Example 2 was applied to the cleaned wafer using a coating device CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron Co., Ltd. The coated film was baked in air at 205°C for 60 seconds to obtain a 12-inch silicon wafer on which a coating film with a thickness of 200 nm was formed.

[0105] <Example 5> A 12-inch silicon wafer was baked at 400°C for 60 seconds using a coating apparatus CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron. The resist underlayer film-forming composition obtained in Preparation Example 1 was coated onto the baked wafer using a coating apparatus CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron. The coated film was baked in the atmosphere at 240°C for 60 seconds and then further baked in the atmosphere at 400°C for 60 seconds, yielding a 12-inch silicon wafer on which a coating film with a thickness of 800 nm was formed.

[0106] <Comparative Example 1> The resist underlayer film-forming composition obtained in Preparation Example 2 was applied onto a 12-inch silicon wafer using a coating device CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron Co., Ltd. The coated film was baked in air at 205°C for 60 seconds to obtain a 12-inch silicon wafer on which a coating film having a thickness of 200 nm was formed.

[0107] <Comparative Example 2> The resist underlayer film-forming composition obtained in Preparation Example 1 was applied onto a 12-inch silicon wafer using a CLEAN TRACK Lithius Pro AP coating device manufactured by Tokyo Electron Co., Ltd. The coated film was baked in the atmosphere at 240°C for 60 seconds and then further baked in the atmosphere at 400°C for 60 seconds, yielding a 12-inch silicon wafer on which a coating film having a thickness of 800 nm was formed.

[0108] (Defect distribution on wafer) The silicon wafers obtained in Examples 3 to 5 were measured for defects on the film surface using a wafer inspection system, Surfscan SP2XP, manufactured by KLA-Tencor Corporation. The distribution of defects within the wafer is shown in Figure 4, and the number of defects is shown in Table 2.

[0109] [Table 2] As can be seen from Figure 4 and Table 2, in Examples 3 to 5, in which the resist underlayer film-forming composition was applied to 12-inch silicon wafers that had been subjected to ultrapure water rinsing and baking treatment, the characteristic defect distribution at the wafer periphery as seen in Comparative Examples 1 and 2 was not observed, and the number of defects of 70 nm or less was reduced to one-fifth. This indicates that impurities are present on the surface of the 12-inch silicon wafer, and that these impurities are components that can be removed by ultrapure water rinsing or baking treatment. This indicates that by performing ultrapure water rinsing and baking treatment before applying a resist underlayer film to the wafer, it is possible to form a coating film without being affected by impurities on the wafer surface. [Industrial Applicability]

[0110] The method of the present application makes it possible to detect impurities present on the surface of semiconductor manufacturing wafers that would otherwise be removed by heating and / or ultrapure water cleaning. These impurities may include fluorine atoms. This provides a method for manufacturing and sorting semiconductor manufacturing wafers (so-called bare wafers) that remove impurities that would otherwise be undetectable.

Claims

1. A method for detecting impurities on a surface of a wafer for semiconductor manufacturing, comprising: The method for detecting impurities on the surface of a wafer used in semiconductor manufacturing includes a step of applying a film-forming composition to the surface of the wafer and baking the composition to form a film having a thickness of 25 nm to 800 nm, and then a step of detecting the impurities using a wafer inspection device.

2. The method for detecting impurities according to claim 1 , wherein the impurities include fluorine atoms.

3. The method for detecting impurities according to claim 1 or 2, wherein the film-forming composition comprises a resin.

4. 4. The method for detecting impurities according to claim 1, wherein the film-forming composition is a coating film-forming composition for lithography.

5. 5. The impurity detection method according to claim 1, wherein the film-forming composition is a resist underlayer film-forming composition.

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