Cleaning liquid for temporary adhesive for substrate, cleaning method for substrate, and cleaning method for support or substrate

Abstract

The cleaning liquid of the temporary adhesive for substrate contains tetrabutylammonium fluoride, dimethyl sulfoxide, and a liquid compound having a solubility parameter of 8.0 or more and 10.0 or less and having a heteroatom. Preferably, tetrabutylammonium fluoride is contained in an amount of 1% by mass or more and 15% by mass or less in a total of 100% by mass of tetrabutylammonium fluoride, dimethyl sulfoxide, and the liquid compound. In addition, dimethyl sulfoxide is preferably contained in an amount of 5% by mass or more and 30% by mass or less in a total of 100% by mass of tetrabutylammonium fluoride, dimethyl sulfoxide, and the liquid compound.

Description

Technical Field

[0001] The present invention relates to a cleaning liquid for a temporary adhesive for a substrate, a cleaning method for a substrate, and a cleaning method for a support or a substrate. Background Art

[0002] Three-dimensional semiconductor mounting is becoming increasingly necessary to achieve further high density and large capacity. The so-called three-dimensional mounting technology is a semiconductor manufacturing technology that thins a semiconductor chip and stacks multiple layers while wiring it with through silicon vias (TSV). In order to realize this technology, it is necessary to grind the non-circuit forming surface (also referred to as the "back side" in this specification) to thin the substrate on which the semiconductor circuit is formed and to perform the process of forming electrodes including TSV on the back side. In the past, in the back grinding process of the silicon substrate, a back protective tape was pasted on the opposite side of the grinding surface to prevent chip breakage during grinding. However, the protective tape uses an organic resin film for the substrate and has flexibility. On the other hand, the strength and heat resistance are insufficient, and it is not suitable for the TSV formation process and the wiring layer formation process on the back side.

[0003] Therefore, a system is proposed that can fully withstand the processes of back grinding, TSV, and back electrode formation by bonding a semiconductor substrate to a support such as silicon or glass via an adhesive layer. At this time, the adhesive layer when bonding the substrate to the support is important. It is necessary to bond the substrate to the support without a gap and have sufficient durability to withstand the subsequent processes. Furthermore, it is necessary to be able to easily peel off the thin wafer from the support at the end. It should be noted that since the adhesive layer is peeled off at the end, it is also referred to as a "temporary adhesive layer" in this specification.

[0004] After the support is peeled off, a part of the temporary adhesive layer sometimes remains on the surface of the substrate on which the semiconductor circuit is formed. Usually, the remaining temporary adhesive layer is cleaned and removed using a cleaning solution. Patent document 1 describes such a cleaning solution, i.e., a cleaning agent composition for cleaning the surface of a substrate. The cleaning agent composition contains (A) quaternary ammonium salt: 0.1 to 2.0 mass %, (B) water: 0.1 to 4.0 mass % and (C) an organic solvent: 94.0 to 99.8 mass %.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2015-7217 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, the cleaning liquid described in Patent Document 1 has room for improvement in its cleaning power for the temporary adhesive layer remaining on the surface of the substrate.

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cleaning liquid having excellent cleaning power for a temporary adhesive layer remaining on a substrate surface.

[0011] Means for solving problems

[0012] In order to solve the above problems and achieve the purpose, the present invention provides a cleaning liquid for a temporary adhesive for a substrate, comprising tetrabutylammonium fluoride, dimethyl sulfoxide, and a liquid compound having a heteroatom and having a solubility parameter of 8.0 to 10.0.

[0013] It is preferred that the tetrabutylammonium fluoride is contained in an amount of 1% by mass or more and 15% by mass or less in 100% by mass of the total of the tetrabutylammonium fluoride, the dimethyl sulfoxide, and the liquid compound.

[0014] It is preferred that the dimethyl sulfoxide is contained in an amount of 5 mass % or more and 30 mass % or less in 100 mass % of the total of the tetrabutylammonium fluoride, the dimethyl sulfoxide and the liquid compound.

[0015] The liquid compound is preferably a compound having a ketone group or an ester group.

[0016] The substrate cleaning method involved in the present invention includes the following steps: peeling off the support body from a substrate stack including a support body, a temporary adhesive layer formed on the support body, and substrates stacked on the temporary adhesive layer in a manner in which the surfaces having circuit surfaces are opposite to each other, and using a cleaning solution of the temporary adhesive for the substrate to clean and remove the temporary adhesive layer remaining on the substrate.

[0017] The method for cleaning a support or substrate according to the present invention comprises the steps of forming a temporary adhesive layer on the support or substrate and cleaning and removing a part of the temporary adhesive layer using a cleaning solution of the temporary adhesive for the substrate.

[0018] Effects of the Invention

[0019] According to the present invention, it is possible to provide a cleaning liquid having excellent cleaning power for a temporary adhesive layer remaining on a substrate surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a figure for demonstrating a substrate laminated body. DETAILED DESCRIPTION

[0021] The present invention is described in more detail below.

[0022] <Cleaning liquid for temporary adhesive for substrate>

[0023] A cleaning liquid for a temporary adhesive for a substrate according to an embodiment includes tetrabutylammonium fluoride, dimethyl sulfoxide, and a liquid compound having a solubility parameter of 8.0 to 10.0 and having a heteroatom.

[0024] In order to perform a back grinding process of a substrate on which a semiconductor circuit is formed, for example, the substrate and the support are joined via a temporary adhesive layer containing a temporary adhesive for the substrate. As for the temporary adhesive for the substrate, specifically, a silicone adhesive is used. After the back grinding process, if the support is peeled off, sometimes a part of the temporary adhesive for the substrate constituting the temporary adhesive layer remains on the surface of the substrate. The cleaning liquid for the temporary adhesive for the substrate involved in the embodiment is suitable for cleaning such a temporary adhesive for the substrate remaining on the surface of the substrate. If the cleaning liquid for the temporary adhesive for the substrate involved in the embodiment is used for cleaning, the above-mentioned remaining temporary adhesive for the substrate (that is, the silicone adhesive) can be fully removed. This is because, in the cleaning liquid for the temporary adhesive for the substrate involved in the embodiment, tetrabutylammonium fluoride and dimethyl sulfoxide are used in combination. Furthermore, of course, the cleaning liquid for the temporary adhesive for the substrate involved in the embodiment is not limited to the substrate thinned by the back grinding process, and the temporary adhesive for the substrate remaining on the surface of the substrate can be appropriately cleaned.

[0025] The solubility parameter of the liquid compound contained in the cleaning solution is greater than 8.0 and less than 10.0. Preferably, it is greater than 8.0 and less than 9.5. The solubility parameter (SP value, δ) is a parameter defined in the regular solution theory proposed by Hildebrand and Scott. If V is set as the molar molecular volume of the solvent and ΔE is set as the condensation energy (evaporation energy), the solubility parameter is expressed by δ = (ΔE / V) 1 / 2 (cal / cm 3 ) 1 / 2 express.

[0026] In addition, the liquid compound has heteroatoms. Examples of heteroatoms include oxygen atoms. Specifically, the liquid compound is preferably a compound having a keto group (-C(C=O)-) or an ester group (-OC(C=O)-). Since the liquid compound has a solubility parameter within the above range and has specific heteroatoms (such as the above groups), it is easy to mix with the silicone adhesive and can fully remove the silicone adhesive.

[0027] As such liquid compounds, specifically, methyl isobutyl ketone (δ=8.4), methyl isopropyl ketone (δ=8.5), methyl n-propyl ketone (δ=8.7), methyl ethyl ketone (δ=9.3), cyclohexanone (δ=9.9), acetone (δ=10.0), isobutyl acetate (δ=8.3), n-butyl acetate (δ=8.5), ethyl acetate (δ=9.1), propylene glycol monomethyl ether acetate (δ=9.1) can be listed. The liquid compound can be used alone or in combination of two or more. Among these, n-butyl acetate and propylene glycol monomethyl ether acetate are more preferred in terms of the cleaning power for silicone adhesives.

[0028] In the cleaning liquid of the temporary adhesive for substrates involved in the embodiment, it is preferred that the tetrabutylammonium fluoride is contained in an amount of 1% by mass or more and 15% by mass or less in a total of 100% by mass of tetrabutylammonium fluoride, dimethyl sulfoxide and the liquid compound. More preferably, it is 3% by mass or more and 15% by mass or less. If tetrabutylammonium fluoride is contained in the above range, the silicone-based adhesive can be fully removed. In addition, if it is less than 1% by mass, it is possible that the cleaning becomes insufficient, and if it exceeds 15% by mass, it is possible to corrode the substrate.

[0029] In addition, in the cleaning liquid of the temporary adhesive for substrates involved in the embodiment, it is preferred that dimethyl sulfoxide is contained in an amount of 5% by mass or more and 30% by mass or less in a total of 100% by mass of tetrabutylammonium fluoride, dimethyl sulfoxide and liquid compounds. More preferably, it is 10% by mass or more and 30% by mass or less. If dimethyl sulfoxide is included in the above range, the silicone-based adhesive can be fully removed. In addition, if it is less than 5% by mass, it is possible that the cleaning becomes insufficient, and if it exceeds 30% by mass, it is possible to corrode the substrate.

[0030] In addition, the cleaning solution of the temporary adhesive for substrates involved in the embodiment may include surfactants, chelating agents, antioxidants, rust inhibitors, defoamers, pH regulators, aromatic compounds as other components. In particular, as surfactants, nonionic, anionic, and cationic surfactants are all possible, and nonionic surfactants of polyether systems can be listed. Other components can be used alone or in combination of more than two. For example, in the case of addition, relative to a total of 100 parts by mass of tetrabutylammonium fluoride, dimethyl sulfoxide, and liquid compounds, other components can be contained in an amount of more than 0.01 parts by mass and less than 10 parts by mass.

[0031] The preparation method of the cleaning liquid for the temporary adhesive for substrates according to the embodiment is not particularly limited. The cleaning liquid for the temporary adhesive for substrates according to the embodiment is obtained by mixing the above components, for example. The order of mixing the above components is not particularly limited.

[0032] The cleaning liquid for the temporary adhesive for substrates according to the embodiment preferably has a flash point of 21° C. or higher. When the flash point is within the above range, cleaning with the cleaning liquid can be performed safely.

[0033] <Substrate cleaning method>

[0034] The cleaning method of the substrate involved in the embodiment includes the following steps: peeling the support body from a substrate laminate including a support body, a temporary adhesive layer formed on the support body, and a substrate laminated in a manner that the temporary adhesive layer has a circuit surface and faces each other, and cleaning and removing the temporary adhesive layer remaining on the substrate using a cleaning liquid of the temporary adhesive for the substrate. If the cleaning liquid of the temporary adhesive for the substrate is used, the temporary adhesive layer remaining on the substrate (i.e., the silicone adhesive remaining on the substrate in the silicone adhesive constituting the temporary adhesive layer) can be fully removed.

[0035] The cleaning method of the substrate involved in the embodiment specifically includes: (a) a step of preparing a substrate stack, (b) a step of grinding or polishing the back side of the substrate in the substrate stack, (c) a step of processing the back side of the substrate, (d) a step of peeling the support from the substrate stack, and (e) a step of cleaning the surface of the substrate using a cleaning solution of the temporary adhesive for the substrate. Here, the case where the temporary adhesive layer is formed by using a cured layer (A) obtained by curing an uncured composition layer of a thermosetting organopolysiloxane is described.

[0036] [Step (a)]

[0037] The step (a) is a step of preparing a substrate laminate. Figure 1 It is a figure for demonstrating a substrate laminated body. Figure 1 The cross-sectional view of the substrate laminate 10 is shown. The substrate laminate 10 includes a support 1, a temporary adhesive layer 2 formed on the support 1, and substrates 3 laminated on the temporary adhesive layer 2 so that surfaces having circuit surfaces face each other.

[0038] In step (a), specifically, the circuit-forming surface of a substrate having a circuit-forming surface on the surface and a circuit-non-forming surface on the back is bonded to a support via a temporary adhesive layer (cured layer (A)). More specifically, step (a) comprises: (a-1) a step of laminating an uncured composition layer of a thermosetting organopolysiloxane or a thermoplastic organopolysiloxane as a silicone-based adhesive on a support, (a-2) a step of pasting the support and the substrate via the uncured composition layer, and (a-3) a step of thermally curing the uncured composition layer to form a cured layer (A). Among them, step (a-1) is a step (a-1') of laminating an uncured composition layer on a substrate, and step (a-2) may be a step (a-2') of pasting the substrate and the support via the uncured composition layer obtained in step (a-1').

[0039] In step (a-1) or (a-1'), when laminating the uncured composition layer, a film of the uncured composition may be used. Alternatively, a solution of the uncured composition may be laminated by spin coating, slit coating, spray coating, etc. Preferably, lamination is performed by spin coating. In this case, usually, after spin coating, pre-baking is performed at a temperature of 80°C to 250°C, preferably 100°C to 230°C, depending on the volatilization conditions of the solvent contained in the uncured composition.

[0040] In addition, in step (a-1) or (a-1'), the uncured composition layer is preferably formed in a manner that the film thickness is 10 μm or more and 150 μm or less. If it is 10 μm or more, the substrate and the support body are pasted without a gap, and the grinding process described later can be fully tolerated. If it is 150 μm or less, the deformation of the resin in the heat treatment process such as the TSV formation process described later can be suppressed, and it can be tolerated for practical use.

[0041] In step (a-2) or (a-2'), the substrate is uniformly pressed under reduced pressure at, for example, 40° C. to 250° C., preferably 60° C. to 200° C. to adhere the support body to the substrate. When adhering, a commercially available wafer bonding apparatus is used, such as EVG520IS, 850TB (trade name) manufactured by EVG, XBC300 (trade name) manufactured by SUSS, Synapse V (trade name) manufactured by Tokyo Elektronik Co., Ltd., etc.

[0042] In step (a-3), the thermosetting organopolysiloxane is cured by heating the uncured composition layer at 120° C. to 250° C., preferably 140° C. to 200° C., for 10 minutes to 4 hours, preferably 30 minutes to 2 hours.

[0043] The substrate used in step (a) is usually a semiconductor wafer. Examples of semiconductor wafers include silicon wafers, germanium wafers, gallium-arsenic wafers, gallium-phosphorus wafers, and gallium-arsenic-aluminum wafers. The thickness of the wafer is not particularly limited, but is typically 600 μm to 800 μm, more typically 625 μm to 775 μm.

[0044] Examples of the support used in step (a) include substrates such as a silicon wafer, a glass plate, and a quartz wafer.

[0045] Here, the uncured composition of the thermosetting organopolysiloxane and the cured layer (A) containing the cured product thereof, which are used in the step (a), will be described in more detail.

[0046] (Uncured composition)

[0047] The uncured composition, for example, comprises (A-1) an organopolysiloxane having two or more alkenyl groups in one molecule, (A-2) an organohydrogenpolysiloxane containing two or more hydrogen atoms (Si-H groups) bonded to silicon atoms in one molecule, and (A-3) a platinum-based catalyst. The molar ratio of the Si-H groups in the component (A-2) to the alkenyl groups in the component (A-1) is 0.3 or more and 10 or less. In addition, the uncured composition may contain (A-4) an organic solvent or (A-5) a reaction control agent.

[0048] Component (A-1) is an organopolysiloxane having two or more alkenyl groups in one molecule. Component (A-1) is, for example, a linear or branched diorganopolysiloxane having two or more alkenyl groups in one molecule, or a diorganopolysiloxane having a moiety composed of SiO 4 / 2 The component (A-1) is preferably an organopolysiloxane containing 0.6 mol% to 9 mol% (molar number of alkenyl groups / molar number of Si) of alkenyl groups in one molecule.

[0049] Such organopolysiloxane is specifically represented by the following formula (1), (2), and (3). These may be used alone or in combination of two or more.

[0050] R 7 (3-a) X a SiO-(R 7 XSiO) m -(R 7 2SiO) n -SiR 7 (3-a) X a (1)

[0051] R 72(HO)SiO-(R 7 XSiO) p+2 -(R 7 2SiO) q -SiR 7 2(OH) (2)

[0052] (SiO 4 / 2 ) b (R 7 3SiO 1 / 2 ) c (R 7 (3-e) X e SiO 1 / 2 ) d (3)

[0053] In the above formula, R 7 Each independently represents a monovalent hydrocarbon group having no aliphatic unsaturated bond, each independently represents a monovalent organic group containing an alkenyl group, a represents an integer of 0 to 3, and m and n represent 2a+m such that the alkenyl content in one molecule is 0.6 mol% or more and 9 mol% or less. p and q represent p+2 such that the alkenyl content in one molecule is 0.6 mol% or more and 9 mol% or less. e represents an integer of 1 to 3 independently, and b, c, and d represent such that (c+d) / b is 0.3 to 3.0 and d / (b+c+d) is 0.01 to 0.6.

[0054] In the above formula, as R 7 , preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms. 7 Specific examples include alkyl groups such as methyl, ethyl, propyl, and butyl; cycloalkyl groups such as cyclohexyl; and aryl groups such as phenyl and tolyl. Among these, alkyl groups or phenyl groups are preferred.

[0055] X is preferably an organic group having 2 to 10 carbon atoms. Examples of X include alkenyl groups such as vinyl, allyl, hexenyl, and octenyl; (meth)acryloylalkyl groups such as acryloylpropyl, acryloylmethyl, and methacryloylpropyl; (meth)acryloyloxyalkyl groups such as acryloyloxypropyl, acryloyloxymethyl, methacryloyloxypropyl, and methacryloyloxymethyl; cyclohexenylethyl, vinyloxypropyl, and the like. Among these, vinyl is preferred industrially.

[0056] In the above formula (1), if a is 1 to 3, the molecular chain terminal is capped with an alkenyl group. The molecular chain terminal alkenyl group with good reactivity can complete the reaction in a short time, so it is preferred. Furthermore, in industry, a=1 is preferred from the perspective of cost. The diorganopolysiloxane containing an alkenyl group is preferably in an oily or rubbery state.

[0057] The above formula (3) represents an organopolysiloxane having a resin structure. In the above formula (3), e=1 is preferred from an industrial and cost perspective. In addition, the product of the average value of e and d / (b+c+d) is preferably 0.02 to 1.50, more preferably 0.03 to 1.0. The organopolysiloxane having a resin structure can be used as a solution dissolved in an organic solvent.

[0058] Component (A-2) is a crosslinking agent, and is an organohydrogenpolysiloxane having at least two, preferably three or more hydrogen atoms bonded to silicon atoms (Si—H groups) in one molecule. The organohydrogenpolysiloxane is linear, branched or cyclic.

[0059] The viscosity of the component (A-2) at 25° C. is preferably 1 mPa·s to 5000 mPa·s, more preferably 5 mPa·s to 500 mPa·s. The organohydrogenpolysiloxane may be used alone or in combination of two or more.

[0060] Component (A-2) is preferably prepared in an amount of preferably 0.3 or more and 10 or less, more preferably 1.0 or more and 8.0 or less, with a molar ratio (Si-H group / alkenyl group) of the Si-H group in component (A-2) and the alkenyl group in component (A-1). If the molar ratio is more than 0.3, the crosslinking density is not excessively reduced, and the uncured composition layer can also be suitably cured. If the molar ratio is less than 10, the crosslinking density is not excessively increased, and sufficient adhesion and viscosity are obtained. In addition, if the molar ratio is less than 10, the usable time of the uncured composition can be extended.

[0061] Component (A-3) is a platinum catalyst (i.e., a platinum group metal catalyst). Examples of the platinum catalyst include chloroplatinic acid, an alcohol solution of chloroplatinic acid, a reactant of chloroplatinic acid and an alcohol, a reactant of chloroplatinic acid and an olefin compound, and a reactant of chloroplatinic acid and a vinyl-containing siloxane. One platinum catalyst may be used alone, or two or more may be used in combination.

[0062] As for component (A-3), relative to the total of component (A-1) and component (A-2), in terms of platinum group metal points (mass conversion), it is desirable to coordinate with an amount of preferably more than 1ppm and less than 5000ppm, more preferably more than 5ppm and less than 2000ppm. If it is more than 1ppm, the curability of the uncured composition layer is difficult to reduce. Therefore, the crosslinking density can be suppressed from reducing, and the holding power can also be suppressed from reducing. If it is less than 5000ppm, the usable time of the uncured composition can be extended.

[0063] Component (A-4) is an organic solvent. As an organic solvent, there is no particular limitation as long as it can dissolve the components of the uncured composition. Examples of organic solvents include hydrocarbon solvents such as pentane, hexane, cyclohexane, isooctane, nonane, decane, terpene, pinene, isododecane, limonene, and organosilicon solvents. One organic solvent may be used alone, or two or more may be used in combination.

[0064] When the component (A-4) is used, it is desirable to mix the component (A-4) in an amount of preferably 10 parts by mass or more and 900 parts by mass or less, more preferably 25 parts by mass or more and 400 parts by mass or less, and further preferably 40 parts by mass or more and 300 parts by mass or less, relative to 100 parts by mass of the total of the components (A-1) and (A-2).

[0065] Component (A-5) is a reaction control agent. The reaction control agent can suppress thickening or gelation of the uncured composition before heat curing when the uncured composition is prepared or applied to a substrate.

[0066] Examples of the reaction control agent include 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclohexanol, 3-methyl-3-trimethylsiloxy-1-butyn, 3-methyl-3-trimethylsiloxy-1-pentyn, 3,5-dimethyl-3-trimethylsiloxy-1-hexyn, 1-ethynyl-1-trimethylsiloxycyclohexane, bis(2,2-dimethyl-3-butynyloxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, and 1,1,3,3-tetramethyl-1,3-divinyldisiloxane. Among these, 1-ethynylcyclohexanol and 3-methyl-1-butyn-3-ol are preferred. The reaction control agent may be used alone or in combination of two or more.

[0067] When using component (A-5), it is desirable to mix component (A-5) in an amount of preferably 0.01 to 8.0 parts by mass, more preferably 0.05 to 2.0 parts by mass, relative to 100 parts by mass of the total of component (A-1) and component (A-2). If it is 8.0 parts by mass or less, the curability of the uncured composition layer is difficult to reduce. If it is 0.01 parts by mass or more, the effect of reaction control is fully exerted.

[0068] In addition, the uncured composition may further contain other components. Other components include fillers such as silica; non-reactive polyorganosiloxanes such as polydimethylsiloxane and polydimethyldiphenylsiloxane; antioxidants such as phenolic, quinone, amine, phosphorus, phosphite, sulfur, and thioether; light stabilizers such as triazole and benzophenone; flame retardants such as phosphate, halogen, phosphorus, and antimony; antistatic agents such as cationic active agents, anionic active agents, and nonionic active agents. Other components may be used alone or in combination of two or more.

[0069] Other components are added within a range that does not hinder the purpose of the present invention. For example, in order to improve heat resistance, when a filler is used, the filler is preferably added in an amount of 50 parts by mass or less relative to 100 parts by mass of the total of component (A-1) and component (A-2).

[0070] (Solidified layer (A))

[0071] The cured layer (A) is obtained by thermally curing the uncured composition layer as described above, and includes a cured product of the uncured composition.

[0072] The peeling force when the cured layer (A) stacked on the support is peeled off from the support interface is, for example, more than 10mN / 25mm and less than 500mN / 25mm, preferably more than 30mN / 25mm and less than 500mN / 25mm, more preferably more than 50mN / 25mm and less than 200mN / 25mm. Wherein, the peeling force is the peeling peeling force obtained in the 180° peeling test in which the 25mm wide test piece is lifted and peeled off with 5mm / second. If it is more than 10mN / 25mm, it is possible to suppress the peeling in the processing steps described later. If it is less than 500mN / 25mm, it is possible to easily peel off the cured layer (A) from the support.

[0073] In addition, the peeling force when the cured layer (A) stacked on the substrate is peeled off from the substrate interface is, for example, more than 50mN / 25mm and less than 1000mN / 25mm, preferably more than 70mN / 25mm and less than 1000mN / 25mm, more preferably more than 80mN / 25mm and less than 500mN / 25mm. Wherein, the peeling force is the peeling peeling force obtained in the 180° peeling test of 25mm wide test piece being lifted and peeled off with 5mm / second. If more than 50mN / 25mm, it is possible to suppress the peeling in the processing steps described later. Even if particularly by high temperature process, it is difficult to produce peeling. If less than 1000mN / 25mm, then the cured layer (A) can be peeled off from the substrate using adhesive tape.

[0074] The cured product contained in the cured layer (A) preferably contains R in an amount of 0.001 mol% or more and 60.000 mol% or less.1 R 2 R 3 SiO 1 / 2 The siloxane unit (M unit) represented by R contains 10.000 mol% or more and 99.999 mol% or less of 4 R 5 SiO 2 / 2 The siloxane unit (D unit) represented by R contains 0.000 mol% or more and 0.005 mol% or less. 6 SiO 3 / 2 The siloxane unit (T unit) represented by the present invention contains SiO in an amount of 0.000 mol% or more and 60.000 mol% or less. 4 / 2 In addition, it is more preferred that the M unit is contained in an amount of 0.001 mol% to 35.000 mol%, the D unit is contained in an amount of 30.000 mol% to 99.999 mol%, the T unit is contained in an amount of 0.000 mol% to 0.001 mol%, and the Q unit is contained in an amount of 0.000 mol% to 50.000 mol%.

[0075] Among them, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 is an organic substituent, which is an unsubstituted or substituted monovalent hydrocarbon group. In the hydrocarbon group, preferably, the number of carbon atoms is 1 to 10. As the hydrocarbon group, specifically, alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, cyclopentyl, and n-hexyl, cycloalkyl groups such as cyclohexyl, aryl groups such as phenyl and tolyl, and groups in which some or all of the hydrogen atoms of these hydrocarbon groups are substituted with halogen atoms can be cited. Among these, methyl and phenyl are preferred.

[0076] In addition, the storage modulus of the cured layer (A) at 25°C is preferably 1×10 6 Pa or more and 1×10 9 Pa or less. If the storage elastic modulus is within the above range, the substrate can be sufficiently withstood in the polishing process described later, and the warping of the substrate can be reduced. Therefore, it is less likely to cause problems such as being unable to be mounted on the device during the process.

[0077] [Step (b)]

[0078] Step (b) is a step of grinding or polishing the back side of the substrate in the substrate laminate. In step (b), the back side (circuit non-forming side) of the substrate bonded to the support body is ground or polished. As a result, the thickness of the substrate becomes thinner. The thickness of the thinned substrate is typically 5 μm or more and 300 μm or less, more typically 10 μm or more and 100 μm or less. There is no particular restriction on the grinding method, and it can be carried out in a known manner. Grinding is preferably carried out while pouring water to cool the substrate and the grindstone (diamond, etc.). As an apparatus for back grinding of the substrate, for example, DAG-810 (trade name) manufactured by DISCO Co., Ltd. can be cited. In addition, CMP grinding can be performed on the back side of the substrate.

[0079] [Step (c)]

[0080] Process (c) is a process for processing the back side of the substrate. In process (c), the back side (circuit non-forming side) of the substrate thinned by back grinding or back polishing in process (b) is processed. In this process, various processes used at the wafer level are included. As this process, electrode formation, metal wiring formation, protective film formation, etc. can be listed. More specifically, metal sputtering for forming electrodes, wet etching for etching the metal sputtering layer, coating of a mask for making metal wiring formation, formation of a pattern using exposure and development, stripping of the resist, dry etching, formation of a metal plating layer, silicon etching for TSV formation, oxide film formation on the silicon surface, and other previously known processes can be listed. In addition, it also includes cutting the wafer thinned by slicing to chip size.

[0081] [Step (d)]

[0082] Step (d) is a step of peeling the support from the substrate laminate. In step (d), the support is peeled from the substrate laminate processed in step (c). The peeling step is generally carried out under relatively low temperature conditions ranging from room temperature to about 60°C. One of the substrate or the support of the substrate laminate can be fixed horizontally, and the other can be lifted at a certain angle from the horizontal direction. In addition, a protective film can be attached to the polished surface of the substrate, and the substrate and the protective film can be peeled off together by peeling.

[0083] The peeling method specifically includes: (d-1) a step of bonding a dicing tape to a processed surface of a substrate to be processed, (d-2) a step of vacuum-adsorbing the dicing tape surface to an adsorption surface, and (e-3) a step of peeling off the support body from the substrate in a manner of peeling off when the temperature of the adsorption surface is in a range of 10° C. to 100° C. In this case, the support body can be easily peeled off from the substrate, and the subsequent dicing step can be easily performed.

[0084] By such a stripping process, the cured layer (A) is stripped together with the support from the substrate stack to obtain only the substrate. In addition to this situation, the following situation is also included: only the support is stripped from the substrate stack to obtain a substrate stacked with the cured layer (A). In the latter case, the cured layer (A) is further stripped from the substrate, for example, by stripping with a tape, to obtain only the substrate. As a tape for stripping with a tape, a tape of a silicone adhesive material is preferably used. For example, polyester film adhesive tapes No. 646S and No. 648 manufactured by Teraoka Seisakusho Co., Ltd. are preferably used.

[0085] [Step (e)]

[0086] Step (e) is a step of cleaning the surface of the substrate using a cleaning solution of the above-mentioned temporary adhesive for the substrate. In step (e), the curing layer (A) (cured material of the uncured composition) remaining on the surface (circuit forming surface) of the substrate is cleaned and removed using a cleaning solution of the above-mentioned temporary adhesive for the substrate. Thus, after the support and the curing layer (A) are peeled off using step (d), the curing layer (A) remaining on the surface of the substrate can also be fully removed. Such a substrate (thin wafer) is then suitable for use in a three-dimensional semiconductor mounting process.

[0087] The substrate can be cleaned by immersing it in a cleaning solution of the temporary adhesive for the substrate. The immersion time is, for example, more than 10 seconds and less than 30 minutes, preferably about more than 30 seconds and less than 10 minutes. In addition, the cleaning solution of the temporary adhesive for the substrate can be sprayed on the substrate. Furthermore, the cleaning solution of the temporary adhesive for the substrate can be used for paddle cleaning, and vibration or ultrasonic cleaning can also be performed. When cleaning, the temperature is, for example, more than 10°C and less than 50°C, preferably more than 20°C and less than 40°C.

[0088] Furthermore, the cleaned substrate may be washed with water or rinsed with alcohol and then dried.

[0089] In the cleaning method of the substrate involved in the above-mentioned embodiment, in step (a), the uncured composition layer of the thermosetting organopolysiloxane is cured to form a cured layer (A) as a temporary adhesive layer. As a temporary adhesive layer, it is not limited to the cured layer (A), and a temporary adhesive layer obtained by other silicone adhesives can be used. In addition, the cured layer (A) is a single layer, but more than two layers of temporary adhesive layers can also be provided. The temporary adhesive layer on the cured layer (A) is silicone-based, acrylic-based, phenolic-based, etc., and is not particularly limited. In addition, a layer containing organopolysiloxane having functions other than the temporary adhesive layer can be provided between the support and the substrate. Specifically, as other silicone adhesives, silicone adhesives described in International Publication No. 2015 / 115060, Japanese Patent Publication No. 2012-144616, and Japanese Patent Publication No. 2014-131004 can be cited. In any case, as long as the cleaning liquid for the temporary adhesive for a substrate is used, the temporary adhesive layer remaining on the surface of the substrate can be sufficiently removed.

[0090] In addition, in the cleaning method of the substrate related to the above-mentioned embodiment, in step (d), the support body can be peeled off as mentioned above, and the peeling of the support body can be light peeling, heating peeling, solvent peeling, mechanical peeling. In any case, as long as the cleaning liquid of the above-mentioned substrate temporary adhesive is used, the temporary adhesive layer remaining on the substrate surface can be fully removed.

[0091] As for photo-stripping, usually, in step (a), a separation layer is formed on the substrate stack. That is, a separation layer is formed between the support and the temporary adhesive layer. As for the separation layer, for example, it is a known material that absorbs light irradiated through the support and is modified, and there is no particular limitation, for example, it is formed by carbon, aromatic hydrocarbon compounds, etc. The so-called modification means a state in which the separation layer is destroyed by a slight external force, or a state in which the adhesion between the separation layer and the adjacent layer is reduced. Secondly, for the substrate stack with a separation layer, steps (b) and (c) are performed as described above. Secondly, in step (d), the support is separated from the substrate stack by photo-stripping. Among them, for the substrate stack, light emitted by a known laser is irradiated through the support. At this time, a laser that irradiates light of a wavelength that can modify the material constituting the separation layer can be appropriately selected. Thus, the separation layer is modified and the support is peeled off. Secondly, in step (e), the surface of the substrate obtained by photo-stripping is cleaned using a cleaning solution of the above-mentioned temporary adhesive for the substrate.

[0092] As for thermal peeling, usually, in step (a), a temporary adhesive layer is formed using a silicone adhesive whose adhesive force decreases due to heating. Next, for a substrate stack having such a temporary adhesive layer, steps (b) and (c) are performed as described above. Next, in step (d), the support is separated from the substrate stack by thermal peeling. Next, in step (e), the surface of the substrate obtained by thermal peeling is cleaned using a cleaning solution of the above-mentioned temporary adhesive for the substrate.

[0093] As for solvent stripping, in step (d), the support is separated from the substrate laminate by solvent stripping. At this time, a solvent that can dissolve the silicone adhesive constituting the temporary adhesive layer can be appropriately selected, and examples thereof include hydrocarbons, aromatics, ethers, etc. having 4 to 20 carbon atoms. Next, in step (e), the surface of the substrate obtained by solvent stripping is cleaned using a cleaning solution of the temporary adhesive for the substrate.

[0094] In addition, in the cleaning method of the substrate that the above-mentioned embodiment relates to, in operation (a), the entire surface of the circuit formation surface of substrate is joined to support body via the temporary adhesive layer obtained by a kind of uncured composition. To this, in order to adjust the bonding force of support body and substrate, the 1st temporary adhesive layer can be formed at a part of substrate surface, and the 2nd temporary adhesive layer is formed at the remainder of substrate surface. That is, the entire surface of substrate surface can be covered with the 1st temporary adhesive layer and the 2nd temporary adhesive layer. With regard to the 1st temporary adhesive layer and the 2nd temporary adhesive layer, in order to obtain desired bonding force, select suitable silicone-based adhesive separately and form.

[0095] Furthermore, in this case, when forming a temporary adhesive layer, it is also preferred to use a cleaning solution of the above-mentioned temporary adhesive for the substrate. First, the first temporary adhesive layer is formed on the entire surface of the substrate. Secondly, the cleaning solution of the above-mentioned temporary adhesive for the substrate is used to perform edge cutting on the unnecessary part of the first temporary adhesive layer (the part forming the second temporary adhesive layer). If the cleaning solution of the above-mentioned temporary adhesive for the substrate is used, the unnecessary part of the first temporary adhesive layer can be cleanly and neatly removed from the substrate. The second temporary adhesive layer is formed on the part of the edge cutting. Then, the circuit forming surface of the substrate is joined to the support via the first temporary adhesive layer and the second temporary adhesive layer. Secondly, in step (b), the back side of the substrate in the substrate laminate having the first temporary adhesive layer and the second temporary adhesive layer is ground or polished. Furthermore, in the above, a temporary adhesive layer is formed on the substrate, but a temporary adhesive layer can also be formed on the support. That is, the support or substrate cleaning method according to the embodiment includes the steps of forming a temporary adhesive layer on the support or substrate and cleaning and removing a portion of the temporary adhesive layer using the cleaning solution of the temporary adhesive for the substrate.

[0096] In addition, the present invention is not limited by the above-mentioned embodiment. The scheme that the above-mentioned various constituent elements are appropriately combined and constituted is also included in the present invention. In addition, for those skilled in the art, further effects and variations can be easily derived. Therefore, the wider mode of the present invention is not limited to the above-mentioned embodiment, and various changes can be made.

[0097] [Example]

[0098] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

[0099] <Cleaning liquid for temporary adhesive for substrate>

[0100] [Example 1-1]

[0101] Tetrabutylammonium fluoride and dimethyl sulfoxide were added to propylene glycol monomethyl ether acetate, and the mixture was stirred at room temperature to obtain a cleaning liquid (1-1). Furthermore, tetrabutylammonium fluoride was dissolved in the cleaning liquid (1-1). The cleaning liquid was prepared in such a manner that tetrabutylammonium fluoride was contained in an amount of 10% by mass in a total of 100% by mass of tetrabutylammonium fluoride, dimethyl sulfoxide and propylene glycol monomethyl ether acetate. In addition, the cleaning liquid was prepared in such a manner that dimethyl sulfoxide was contained in an amount of 20% by mass in a total of 100% by mass of tetrabutylammonium fluoride, dimethyl sulfoxide and propylene glycol monomethyl ether acetate.

[0102] [Example 1-2]

[0103] A cleaning liquid (1-2) was obtained in the same manner as in Example 1-1 except that butyl acetate was used instead of propylene glycol monomethyl ether acetate.

[0104] [Examples 1-3]

[0105] A cleaning liquid (1-3) was obtained in the same manner as in Example 1-1 except that the cleaning liquid was prepared so as to contain 5 mass % of tetrabutylammonium fluoride in 100 mass % of the total of tetrabutylammonium fluoride, dimethyl sulfoxide and propylene glycol monomethyl ether acetate.

[0106] [Examples 1-4]

[0107] Tetrabutylammonium fluoride and dimethyl sulfoxide were added to propylene glycol monomethyl ether acetate, and the mixture was stirred at room temperature to obtain a cleaning liquid (1-4). Furthermore, tetrabutylammonium fluoride was dissolved in the cleaning liquid (1-4). The cleaning liquid was prepared in such a manner that tetrabutylammonium fluoride was contained in an amount of 10% by mass in a total of 100% by mass of tetrabutylammonium fluoride, dimethyl sulfoxide and propylene glycol monomethyl ether acetate. In addition, the cleaning liquid was prepared in such a manner that dimethyl sulfoxide was contained in an amount of 10% by mass in a total of 100% by mass of tetrabutylammonium fluoride, dimethyl sulfoxide and propylene glycol monomethyl ether acetate.

[0108] [Comparative Example 1-1]

[0109] Dimethyl sulfoxide was added to propylene glycol monomethyl ether acetate, and the mixture was stirred at room temperature to obtain a cleaning liquid (1-5). The cleaning liquid was prepared so that dimethyl sulfoxide was contained in an amount of 20% by mass based on 100% by mass of the total of dimethyl sulfoxide and propylene glycol monomethyl ether acetate.

[0110] <Substrate cleaning>

[0111] [Example 2-1]

[0112] First, a resin solution was prepared as follows.

[0113] To a solution consisting of 100 parts by mass of polydimethylsiloxane having a molecular side chain with 2.5 mol% of vinyl groups and a number average molecular weight (Mn) of 30,000 and 200 parts by mass of toluene, 40 parts by mass of an organohydrogenpolysiloxane represented by the following formula (M-1) and 0.7 parts by mass of ethynylcyclohexanol were added and mixed. Further, 0.2 parts by mass of a platinum catalyst CAT-PL-5 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was filtered with a 0.2 μm membrane filter to obtain a resin solution. It should be noted that in the resin solution, the molar ratio of the Si-H group of the organohydrogenpolysiloxane containing Si-H groups to the alkenyl group in the organopolysiloxane having alkenyl groups was 1.1.

[0114]

Chemistry 1

[0115]

[0116] Next, the substrate was cleaned as follows.

[0117] [Step (a)]

[0118] Prepare a substrate stack. Specifically, after spin coating the resin solution on a 200 mm glass wafer (thickness: 700 μm) as a support, heat it at 50°C for 3 minutes using a hot plate to laminate an uncured composition layer (thickness: 35 μm). Next, a 200 mm diameter silicon wafer (thickness: 725 μm) with copper columns of 10 μm height and 40 μm diameter formed all over the surface of the substrate is bonded to the support so that the copper column surface faces the uncured composition layer. The bonding is performed using a wafer bonding device (manufactured by EVG, EVG520IS (trade name)). In addition, the bonding temperature is 50°C and the pressure in the chamber during bonding is 10 -3 The bonding was carried out at a pressure of 100 mbar or less and a load of 10 kN. After bonding, the bonded substrates were heated in an oven at 200° C. for 2 hours to cure the uncured composition layer, and then cooled to room temperature. In this way, a substrate laminate was obtained.

[0119] [Step (b)]

[0120] Next, the back surface of the substrate in the substrate stack was ground. Specifically, the back surface of the silicon wafer was ground using a grinding machine (DAG810 (trade name) manufactured by DISCO Corporation) using a diamond grindstone until the final substrate thickness was 50 μm.

[0121] [Step (c)]

[0122] Next, as a step of processing the back surface of the substrate, a heating step was simulated and performed. Specifically, the substrate stack after the back surface grinding was heated on a hot plate at 260° C. for 10 minutes.

[0123] [Step (d)]

[0124] Secondly, the support body is peeled off from the substrate laminate. Specifically, a cutting tape is pasted on the back side of the silicon wafer (circuit non-forming surface) using a cutting frame, and the cutting tape surface is set on the adsorption plate by vacuum adsorption. Then, the glass wafer is peeled off by clamping one point of the glass wafer with tweezers at room temperature. Then, a polyester film adhesive tape No. 648 manufactured by Teraoka Manufacturing Co., Ltd. is pasted on the temporary adhesive layer exposed on the surface, and the tape is peeled off. In this way, the temporary adhesive layer is peeled off from the silicon wafer.

[0125] [Step (e)]

[0126] Next, the surface of the substrate was cleaned using the cleaning solution (1-1). Specifically, the silicon wafer was immersed in the cleaning solution (1-1) for 10 minutes and then dried at room temperature.

[0127] [Example 2-2 to Example 2-4 and Comparative Example 2-1]

[0128] The substrate was cleaned in the same manner as in Example 2-1 except that cleaning liquids (1-2) to (1-5) were used instead of cleaning liquid (1-1).

[0129] <Evaluation Method>

[0130] The amount of Si element present on the surface (circuit formation surface) of the substrate after step (d) was measured by XPS, and the Si content was 23%. The Si content does not include Si derived from the silicon substrate.

[0131] In addition, the amount of Si element present on the surface (circuit formation surface) of the substrate after the step (e) was also measured by XPS.

[0132] When the Si content after cleaning is less than 5%, it can be said that the cleaning liquid has excellent cleaning power for the temporary adhesive layer remaining on the surface of the substrate.

[0133] It should be noted that XPS was performed using an X-ray photoelectron spectrometer (manufactured by ULVAC-PHI, INCORPORATED., PHIQuantera SXM (trade name)). Specifically, monochromatized Alkα was used for the X-ray source, and the analysis was performed at an output power of 25 W (15 kV, 100 μm diameter), a photoelectron extraction angle of 45°, a pass energy of 55.0 eV, and a step resolution of 0.05 eV. In addition, the analysis area was set to φ500 μm.

[0134] <Evaluation Results>

[0135] When the cleaning liquid obtained in Examples 1-1 to 1-4 was used to clean the substrate as in Examples 2-1 to 2-4, the amount of Si remaining after cleaning was less than 3%. On the other hand, when the cleaning liquid obtained in Comparative Example 1-1, which does not meet the requirements of the present invention, was used to clean the substrate as in Comparative Example 2-1, the amount of Si remaining after cleaning was 23%, and good cleaning performance was not obtained.

[0136] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are for illustration only, and any technical solution having substantially the same structure and achieving the same effect as the technical idea described in the patent claims of the present invention is included in the technical scope of the present invention.

[0137] Description of Reference Numerals

[0138] 1…Support

[0139] 2…Temporary adhesive layer (curing layer (A))

[0140] 3…Substrate

[0141] 10…Substrate laminate

Claims

1. A cleaning solution for a temporary adhesive for a substrate, comprising: tetrabutylammonium fluoride; dimethyl sulfoxide; and a liquid compound having a heteroatom and having a solubility parameter of 8.0 or more and 10.0 or less, in, The liquid compound is at least one selected from n-butyl acetate and propylene glycol monomethyl ether acetate; The tetrabutylammonium fluoride is contained in an amount of 3 mass % or more and 15 mass % or less in 100 mass % of the total of the tetrabutylammonium fluoride, the dimethyl sulfoxide and the liquid compound; The dimethyl sulfoxide is contained in an amount of 10% by mass or more and 30% by mass or less in 100% by mass of the total of the tetrabutylammonium fluoride, the dimethyl sulfoxide and the liquid compound.

2. A method for cleaning a substrate, characterized in that: The method comprises the following steps: peeling off the support body from a substrate laminate comprising a support body, a temporary adhesive layer formed on the support body, and a substrate laminated on the temporary adhesive layer in a manner opposite to a surface having a circuit surface, and cleaning and removing the temporary adhesive layer remaining on the substrate using a cleaning solution of the temporary adhesive for the substrate according to claim 1.

3. A method for cleaning a support or substrate, characterized in that: The method comprises the steps of forming a temporary adhesive layer on a support or a substrate, and cleaning and removing a part of the temporary adhesive layer using a cleaning solution for the temporary adhesive for a substrate according to claim 1.

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