Wafer processing method

Abstract

The present invention provides a method for detecting impurities on a surface of a silicon wafer for manufacturing semiconductors, the impurities not being able to be detected by a conventional inspection method, a method for manufacturing the silicon wafer for manufacturing semiconductors having the impurities removed from the surface thereof, and a method for screening wafers for manufacturing semiconductors. This method for detecting impurities on a surface of a wafer for manufacturing semiconductors includes: a step for coating the surface of the wafer with a film-forming composition, and performing baking to form a film; and then a step for detecting impurities by means of a wafer inspection device.

Description

Technical Field

[0001] The present application relates to a method for detecting impurities on the surface of a silicon wafer for semiconductor manufacturing, a method for manufacturing a semiconductor manufacturing wafer from which impurities on the wafer surface have been removed, and a method for selecting a semiconductor manufacturing wafer, etc., which are wafer processing methods.

Background Art

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

[0003] Patent Document 1 describes a foreign matter detection method capable of detecting, with high reliability, foreign matter buried inside a photoresist coating film using a reflective specimen having a photoresist coating film formed on a semiconductor substrate such as a silicon substrate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] To provide a method for detecting impurities on the surface of a silicon wafer for semiconductor manufacturing, a method for manufacturing a semiconductor manufacturing wafer from which impurities on the wafer surface have been removed, and a method for selecting a semiconductor manufacturing wafer, which cannot be detected by conventional inspection methods.

Means for Solving the Problems

[0006] The present invention includes the following.

[0007] [1] A method for detecting impurities on the surface of a semiconductor manufacturing wafer, comprising: A method for detecting impurities on the surface of a semiconductor manufacturing wafer, comprising a step of applying a film-forming composition to the wafer surface, baking it to form a film, and then a step of detecting impurities with a wafer inspection apparatus.

[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 an underlayer film-forming composition for resist.

[0012] [6] A method for manufacturing a semiconductor manufacturing wafer from which impurities on the wafer surface have been removed, a step of heating the raw semiconductor manufacturing wafer (I) at 100°C to 500°C and / or a step of washing with ultrapure water (step A), a step 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] (step B), a step of 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 is reduced by 80% or more compared to the raw semiconductor manufacturing wafer (I) The method for manufacturing a semiconductor manufacturing wafer from which impurities on the wafer surface have been removed, comprising the above steps.

[0013] [7] A method for sorting semiconductor manufacturing wafers, a step of heating the raw semiconductor manufacturing wafer (I) at 100°C to 500°C and / or a step of washing with ultrapure water (step A), a step of inspecting the semiconductor manufacturing wafer that has undergone the step (A) by the impurity detection method according to any one of [1] to [5] (step B), 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 wafer inspection apparatus may use commercially available products. As a specific example, the Surfscan series of wafer inspection systems manufactured by KLA-Tencor Corporation can be mentioned.

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

[0022] It is preferable that the film-forming composition contains a resin. The resin is also referred to as a polymer, a copolymer, a high molecular compound, etc. The resin of the present application may be either an organic resin or an inorganic resin (for example, a hydrolysis condensate of a silane compound, polysiloxane, etc.).

[0023] The coating film-forming composition for lithography used in the present application includes, for example, known photoresist compositions described below, known resist underlayer film-forming compositions (containing organic compounds and / or inorganic compounds), known protective film-forming compositions for protecting the substrate from etching chemicals during semiconductor substrate processing, known underlayer film-forming compositions for self-assembled monolayers, known upper layer film-forming compositions for self-assembled monolayers, and known resist upper layer film-forming compositions, etc., but is not limited thereto.

[0024] The exposure wavelength in the lithography process may be i-line, KrF excimer laser, ArF excimer laser, EUV (extreme ultraviolet), or EB (electron beam). It is preferable that it is a coating film-forming composition for lithography corresponding to these exposure wavelengths.

[0025] Specific examples of the coating film-forming composition for lithography may include a resist upper-layer film-forming composition for a resist upper layer described in International Publication No. WO2014 / 115843, International Publication No. WO2015 / 129486, etc., a lower-layer film-forming composition for a self-assembled film using the self-assembly (DSA, Direct Self Assembly) technology of a block copolymer described in International Publication No. WO2013 / 146600, International Publication No. WO2014 / 097993, etc., for example, an upper-layer film-forming composition for the self-assembled film described in International Publication No. WO2018 / 051907, for example, a coating composition for pattern inversion described in International Publication No. WO2016 / 031563, International Publication No. WO2017 / 145809.

[0026] Other specific examples of the coating film-forming composition for lithography may include a protective film-forming composition, a resist lower-layer forming composition, and a silicon-containing resist lower-layer film-forming composition described in International Publication No. WO2009 / 096340, JP-A No. 2009-053704, International Publication No. WO2010 / 147155, International Publication No. WO2011 / 102470, International Publication No. WO2011 / 021555, International Publication No. WO2013 / 047516, International Publication No. WO2015 / 030060, International Publication No. WO2018 / 052130, International Publication No. WO2019 / 124474, International Publication No. WO2019 / 124475, International Publication No. WO2019 / 151471, International Publication No. WO2019 / 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 3is 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 halogen atoms, nitro groups, amino groups, alkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 40 carbon atoms, formyl groups, carboxyl groups, alkoxy groups, or hydroxy groups. An organic group which may be substituted, and R 2 and R 3 may together with the carbon atom to which they are attached form a ring, T 1 is an arylene group having 6 to 40 carbon atoms, T 3 is 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 -Y-Z 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 from 0 to (5 + 2n), n represents the degree of condensation of the aromatic ring constituting the arylene group defined by T 1 , m1 is an integer from 2 to 3600. It is preferably ].

[0032] Said R 1 is the following formula (2):

Chemical formula

[0033] The structural group (C) is represented by the following formula (1-1):

Chemical formula

[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 above reaction product (C’) is represented by the following formulas (13), (14), and (15):

Chemical formula

[0040] In addition, the entire disclosure of International Publication No. 2011 / 021555 is incorporated herein by reference.

[0041] As an example of the specific structure of a preferred resin (polymer), the following formula (21):

[0042]

Chemical formula

Chemical formula

[0043] The resin (polymer) of the present application includes, for example, the polymers described in International Publication No. 2009 / 096340, and reaction products of a bifunctional or higher-functional compound having at least one disulfide bond and a trifunctional or higher-functional compound described in International Publication No. 2019 / 151471, but is not limited thereto.

[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 above compound (A”), a 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): [Chemical formula] (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 to 1, m represents an integer of 0 or 1, Z1 represents a group represented by the following formula (32), formula (33) or formula (34): [Chemical formula] In the above formula (33), X represents a group represented by the following formula (44), formula (45) or formula (46): [Chemical formula] 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 above polymer is preferably represented by the following (Formula P-6) to (Formula P-8).

[0050]

Chemical formula

Chemical formula

Chemical formula

[0051] The entire disclosures of International Publication No. 2009 / 096340 and International Publication No. 2019 / 151471 are incorporated herein by reference.

[0052] <Crosslinking agent> Examples of the crosslinking agent contained as an optional component in the film-forming composition of the present invention include hexamethoxymethylmelamine, tetramethoxymethylbenzoguanamine, 1,3,4,6-tetrakis(methoxymethyl) glycoluril (tetramethoxymethyl glycoluril) (POWDERLINK [registered trademark] 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 [registered trademark]-303, Nikalac [registered trademark] MW-390).

[0053] Further, the above crosslinking agent is represented by the following formula (71) or formula (72) described in International Publication No. 2014 / 208542:

[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 10Each represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms. n9 is an integer of 1 ≤ n9 ≤ 3, n10 is an integer of 2 ≤ n10 ≤ 5, n11 is an integer of 0 ≤ n11 ≤ 3, n12 is an integer of 0 ≤ n12 ≤ 3, and 3 ≤ (n9 + n10 + n11 + n12) ≤ 6 represents an integer. 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 represents an integer. m2 represents an integer of 2 to 10. ) The reaction between the compound represented by the following formula (73) or formula (74) and 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. The crosslinkable compounds represented by formula (71) and formula (72) used in the present invention can be exemplified as follows.

[0058]

Chemical formula

[0059]

Chemical formula

[0060]

Chemical formula

[0061]

Chemical formula

[0062]

Chemical formula

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

[0064] [Chemistry]

[0065] [Chemistry]

[0066] The entire disclosure of International Publication No. 2014 / 208542 is incorporated herein by reference.

[0067] Further, the crosslinking agent may be a nitrogen-containing compound having 2 to 6 substituents represented by the following formula (61) that are bonded to a nitrogen atom, as described in International Publication No. 2017 / 187969.

[0068] [Chemistry] (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] [Chemistry] (In formula (1A), the 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 formulas (1A-1) to (1A-6).

[0070] [Chemistry] The compound represented by the formula (1A) is obtained by reacting a nitrogen-containing compound having 2 to 6 substituents represented by the following formula (62) bonded to a nitrogen atom 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.

Chemical formula

[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).

Chemical formula

Chemical formula

Chemical formula

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

[0077] The step (C) can include, for example, dividing the wafer (III) for semiconductor manufacturing that has undergone the step (B) into a wafer (IV) for semiconductor manufacturing in which the number of defects present on its surface is reduced by 80% or more compared to the wafer (I) for manufacturing a crude semiconductor and a wafer (V) for semiconductor manufacturing in which the reduction is less than 80% compared to the wafer (I) for manufacturing a crude semiconductor, and selecting the wafer (IV) for semiconductor manufacturing.

[0078] The explanation of the terms related to this item shall be in accordance with the explanation content of the <Method for Manufacturing Wafers for Semiconductor Manufacturing>.

Example

[0079] Next, examples will be given to specifically explain the content of the present invention, but the present invention is not limited thereto.

[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 (the solid content of the polymer was 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, 57.63 g of propylene glycol monomethyl ether as a solvent, and 9.58 g of propylene glycol monomethyl ether acetate 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 (the solid content of the polymer was 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 coating apparatus CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron. After baking the applied film at 240 °C for 60 seconds and then further baking at 400 °C for 60 seconds, a 12-inch silicon wafer with a coating film having a film thickness of 800 nm was obtained.

[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 apparatus CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron. A 12-inch silicon wafer with a coating film having a film thickness of 200 nm formed thereon was obtained by baking the film after application at 205 °C for 60 seconds.

[0092] <Reference Example 1> A 12-inch silicon wafer subjected to a heat treatment was obtained by baking a 12-inch silicon wafer at 400 °C for 60 seconds using a coating apparatus CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron.

[0093] <Reference Example 2> Propylene glycol monomethyl ether (PGME), which is the solvent used in the resist underlayer film-forming composition, was applied onto a 12-inch silicon wafer using a coating apparatus CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron. A 12-inch silicon wafer with a coating film formed thereon was obtained by baking the film after application at 205 °C for 60 seconds.

[0094] <Reference Example 3> 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 applied onto the baked 12-inch silicon wafer. After baking the film after application at 240 °C for 60 seconds, it was further baked at 400 °C for 60 seconds to obtain a 12-inch silicon wafer with a coating film having a film thickness of 800 nm formed thereon.

[0095] <Reference Example 4> 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 applied to the baked 12-inch silicon wafer. By baking the film after application at 25 °C for 60 seconds, a 12-inch silicon wafer with a coating film having a film thickness of 200 nm was obtained.

[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 apparatus CLEAN TRACK Lithius Pro AP manufactured by Tokyo Electron. By baking the film after application at 205 °C for 60 seconds, a 12-inch silicon wafer with a coating film having a film thickness of 25 nm was obtained.

[0097] (Defect distribution on the wafer) The silicon wafers obtained in Examples 1 and 2 were measured for 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 Fig. 1, and the number of defects is shown in Table 1. Also, the results of the shape and elemental analysis of the defects detected in Examples 1 and 2 are shown in Figs. 2 and 3, which were carried out using a defect review SEM RS6000 manufactured by Hitachi High-Tech Corporation.

[0098]

Table 1

[0099] In Reference Examples 3 and 4 in which the resist underlayer film-forming composition was applied after pre-baking the 12-inch silicon wafer, no characteristic defect distribution was confirmed at the outer peripheral portion of the wafer, and the number of defects was also small. In addition, Reference Example 1 in which the 12-inch silicon wafer was baked and Reference Example 2 in which a solvent was applied also did not confirm a characteristic defect distribution at the outer peripheral portion of the wafer.

[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 generation distribution on the 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 defect distribution within the wafer is shown in Fig. 4, and the number of defects is shown in Table 2.

[0109] [Table 2] From Fig. 4 and Table 2, it was confirmed that in Examples 3 to 5 where a resist underlayer film forming composition was applied to 12-inch silicon wafers that had been subjected to ultrapure water washing and firing treatment, the characteristic defect distribution in the outer peripheral portion of the wafer as shown in Comparative Examples 1 and 2 was not observed, and the number of defects of 70 nm or less became 1 / 5. From this, it was shown that impurities were present on the surface of the 12-inch silicon wafer, and the impurities were components that could be removed by performing ultrapure water washing or firing treatment. From this, it was shown that it was possible to form a coating film without being affected by impurities on the wafer surface by performing ultrapure water washing and firing treatment before applying the resist underlayer film on the wafer. [Industrial Applicability]

[0110] According to the method of the present application, it becomes possible to detect the presence of impurities on the surface of a semiconductor manufacturing wafer that are removed by performing heating and / or ultrapure water washing treatment. These impurities may contain fluorine atoms. A method for manufacturing and a method for sorting a semiconductor manufacturing wafer (so-called bare wafer) from which impurities that cannot be detected without using this detection method have been removed can be provided.

Claims

A method for manufacturing a semiconductor wafer with impurities removed from its surface, comprising: heating a raw semiconductor wafer (I) at 100°C to 500°C and / or washing it with ultrapure water (step A); applying a film-forming composition to the semiconductor wafer (II) that has undergone step A, firing it to form a film, and then inspecting it by a method for detecting impurities on the surface of a semiconductor wafer, which includes detecting impurities with a wafer inspection apparatus (step B); selecting a semiconductor wafer (IV) from the semiconductor wafers (III) that have undergone step B, wherein the number of defects present on its surface is reduced by 80% or more compared to the raw semiconductor wafer (I) (step C); A method for manufacturing a semiconductor wafer with impurities removed from its surface, comprising the above steps. The method for manufacturing a semiconductor wafer according to claim 1, wherein the impurities contain fluorine atoms. The method for manufacturing a semiconductor wafer according to claim 1 or 2, wherein the film-forming composition contains a resin. The method for manufacturing a semiconductor wafer according to any one of claims 1 to 3, wherein the film-forming composition is a coating film-forming composition for lithography. The method for manufacturing a semiconductor wafer according to any one of claims 1 to 4, wherein the film-forming composition is an underlayer film-forming composition for resist. A method for sorting semiconductor wafers, comprising: heating a raw semiconductor wafer (I) at 100°C to 500°C and / or washing it with ultrapure water (step A); applying a film-forming composition to the semiconductor wafer that has undergone step A, firing it to form a film, and then inspecting it by a method for detecting impurities on the surface of a semiconductor wafer, which includes detecting impurities with a wafer inspection apparatus (step B); selecting a semiconductor wafer (IV) from the semiconductor wafers (III) that have undergone step B, wherein the number of defects present on its surface is reduced by 80% or more compared to the raw semiconductor wafer (step C); including the above steps. The step (C) includes separating the semiconductor manufacturing wafer (III) that has undergone the step (B) into a semiconductor manufacturing wafer (IV) with the number of defects present on its surface reduced by 80% or more compared to the raw semiconductor manufacturing wafer (I), and a semiconductor manufacturing wafer (V) with the number of defects reduced by less than 80% compared to the raw semiconductor manufacturing wafer (I), and selecting the semiconductor manufacturing wafer (IV). A method for selecting a semiconductor manufacturing wafer.

7. The method for selecting a semiconductor manufacturing wafer according to claim 6, wherein the impurity contains a fluorine atom.

8. The method for selecting a semiconductor manufacturing wafer according to claim 6 or 7, wherein the film-forming composition contains a resin.

9. The method for selecting a semiconductor manufacturing wafer according to any one of claims 6 to 8, wherein the film-forming composition is a coating film-forming composition for lithography.

10. The method for selecting a semiconductor manufacturing wafer according to any one of claims 6 to 9, wherein the film-forming composition is an underlayer film-forming composition for resist.

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