Method for producing cleaning composition

Abstract

To provide a production method that enables the production of a cleaning composition with a high etching rate even in a normal air atmosphere without the use of an inert gas.SOLUTION: The present invention provides a method for producing a cleaning composition that contains a quaternary alkyl ammonium fluoride or a hydrate thereof and an organic solvent. The method includes a preparation step in which a quaternary alkyl ammonium fluoride or a hydrate thereof and an organic solvent are mixed while at least a part of the liquid surface in a mixing vessel containing the quaternary alkyl ammonium fluoride or hydrate thereof and the organic solvent is isolated from the gas phase.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a method for producing a cleaning composition. In particular, the present disclosure relates to a method for producing a cleaning composition for decomposing and cleaning an adhesive that contains an adhesive polymer and is used for temporarily bonding a device wafer and a support wafer (carrier wafer) remaining on a device wafer in a semiconductor wafer thinning process. [Background technology]

[0002] In three-dimensional packaging technology for increasing the density of semiconductors, the thickness of each semiconductor wafer is reduced, and multiple semiconductor wafers connected by through-silicon vias (TSVs) are stacked. Specifically, the surface (backside) of a device wafer on which semiconductor devices are formed is polished to make it thinner, and then electrodes including TSVs are formed on the backside.

[0003] In the polishing process of the back surface of the device wafer, a support wafer also called a carrier wafer is temporarily bonded to the semiconductor device forming surface of the device wafer using an adhesive in order to impart mechanical strength to the device wafer. For example, a glass wafer or a silicon wafer is used as the support wafer. After the polishing process, metal wiring or electrode pads containing Al, Cu, Ni, Au, etc., inorganic films such as oxide films and nitride films, or resin layers containing polyimide, etc. are formed on the polished surface (back surface) of the device wafer as necessary. Thereafter, the back surface of the device wafer is bonded to a tape having an acrylic adhesive layer fixed by a ring frame, so that the device wafer is fixed to the tape. Thereafter, the device wafer is separated from the support wafer (debonding), the adhesive on the device wafer is peeled off, and the adhesive residue on the device wafer is washed away using a cleaning agent.

[0004] For the temporary bonding of device wafers, adhesives containing a polyorganosiloxane compound with good heat resistance as an adhesive polymer are used. In particular, when the adhesive polymer is a crosslinked polyorganosiloxane compound, the cleaning agent is required to have two functions: severing Si-O bonds and dissolving decomposition products by a solvent. An example of such a cleaning agent is one in which a fluorine-based compound such as tetrabutylammonium fluoride (TBAF) is dissolved in a polar aprotic solvent. The fluoride ions of TBAF are involved in severing Si-O bonds via the formation of Si-F bonds, and therefore can impart etching performance to the cleaning agent. Polar aprotic solvents can dissolve TBAF and do not form solvates with fluoride ions via hydrogen bonds, and therefore can increase the reactivity of fluoride ions.

[0005] In Non-Patent Document 1 (Advanced Materials, 11, 6, 492 (1999)), a 1.0 M TBAF solution using aprotic THF as a solvent is used to decompose and dissolve and remove polydimethylsiloxane (PDMS).

[0006] In Non-Patent Document 2 (Advanced Materials, 13, 8, 570 (2001)), aprotic solvents such as NMP, DMF and DMSO are used as solvents for TBAF, in addition to THF.

[0007] Non-Patent Document 3 (Macromolecular Chemistry and Physics, 217, 284-291 (2016)) describes the results of investigating the etching rate of PDMS using TBAF / organic solvent for each solvent, and for THF and DMF, which have high etching rates, it also describes a comparison of the etching rates of TBAF solutions using mixed solvents with different THF / DMF ratios.

[0008] In the production of a cleaning composition containing a quaternary alkylammonium fluoride or its hydrate, and an N-substituted amide compound in which a hydrogen atom is not directly bonded to a nitrogen atom, it is known that the cleaning performance is reduced due to oxidation of the N-substituted amide compound due to contact with air (Patent Documents 1 and 2). In order to prevent this, there is a method in which a quaternary alkylammonium fluoride or its hydrate is dissolved under an inert gas atmosphere such as nitrogen gas or argon gas (Patent Document 1). In this method, the N-substituted amide compound and the quaternary alkylammonium fluoride or its hydrate are mixed under an inert gas atmosphere to reduce the dissolved oxygen rate and suppress the oxidation of the N-substituted amide compound. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2021 / 106460 [Patent Document 2] International Publication No. 2023 / 120322 [Non-patent literature]

[0010] [Non-Patent Document 1] Advanced Materials, 11, 6, 492 (1999) [Non-Patent Document 2] Advanced Materials, 13, 8, 570 (2001) [Non-Patent Document 3] Macromolecular Chemistry and Physics, 217, 284-291 (2016) Summary of the Invention [Problem to be solved by the invention]

[0011] Protic solvents such as water readily form solvates when in contact with fluoride ions, or HF2 -It is considered that the activity of the cleaning composition is reduced by forming the above. When quaternary alkyl ammonium fluoride or its hydrate and organic solvent are mixed under an inert gas atmosphere, the liquid surface is covered with low humidity inert gas. Therefore, it is considered that mixing quaternary alkyl ammonium fluoride or its hydrate and organic solvent under an inert gas atmosphere not only suppresses the oxidation of organic solvent, but also has the effect of preventing the moisture contained in air from being mixed in.

[0012] Such a method of sealing the liquid surface with an inert gas is effective. Specifically, the following methods are considered to be effective: a method in which nitrogen gas is introduced into the mixing tank to remove the air inside, and then the quaternary alkylammonium fluoride or hydrate thereof is dissolved; a method in which the quaternary alkylammonium fluoride or hydrate thereof is dissolved while continuously flowing nitrogen gas into the mixing tank; and a method in which the entire mixing tank is placed under a nitrogen gas atmosphere to prevent the inflow of air from the outside, and the quaternary alkylammonium fluoride or hydrate thereof is dissolved.

[0013] However, in large-scale manufacturing processes, the use of inert gases such as nitrogen gas and argon gas entails the risk of oxygen deficiency for workers, and therefore requires the installation of oxygen concentration meters around the equipment and in the room as well as the installation of a shutdown sequence in the process as a safety measure. The installation of such equipment and the use of inert gases are costly, and above all, from the viewpoint of reducing risk to zero, it is preferable not to use inert gases in the process.

[0014] The present disclosure provides a production method that can produce a cleaning composition that has a high etching rate even in a normal air atmosphere without using an inert gas. [Means for solving the problem]

[0015] The present inventors have found that a cleaning composition having the same level of cleaning performance as a cleaning composition produced under an inert gas atmosphere can be prepared even under a normal air atmosphere without using an inert gas, by mixing a quaternary alkylammonium fluoride or a hydrate thereof and an organic solvent while blocking at least a part of the liquid surface from the gas phase.

[0016] That is, the present disclosure relates to the following [1] to

[20] . [1] A method for producing a cleaning composition containing a quaternary alkylammonium fluoride or a hydrate thereof and an organic solvent, comprising the steps of: The method for producing a cleaning composition includes a preparation step of mixing the quaternary alkylammonium fluoride or hydrate thereof, and the organic solvent in a mixing tank containing the quaternary alkylammonium fluoride or hydrate thereof, and the organic solvent, while blocking at least a part of the liquid surface of the mixing tank from a gas phase. [2] The method for producing a cleaning composition according to [1], wherein in the preparation step, a ratio (S2 / S1) of a contact area (S2) of the liquid surface with a gas phase to a horizontal cross-sectional area (S1) of the mixing tank at the height of the liquid surface is less than 0.3. [3] The method for producing a cleaning composition according to [1] or [2], wherein the preparation step is carried out in a state in which a float is installed so as to cover at least a portion of the liquid surface. [4] The method for producing a cleaning composition according to [3], wherein in the preparation step, a ratio (S3 / S1) of a horizontal cross-sectional area (S3) of the float at the height of the liquid level to a horizontal cross-sectional area (S1) of the mixing tank at the height of the liquid level is 0.7 or more. [5] The method for producing a cleaning composition according to any one of [1] to [4], wherein the preparation step is carried out by placing the mixing tank under an air atmosphere. [6] The method for producing a cleaning composition according to any one of [1] to [5], further comprising a storage step of storing the cleaning composition in a state in which at least a part of a liquid surface of a container containing the cleaning composition is isolated from a gas phase after the preparation step. [7] The method for producing a cleaning composition described in [6], wherein, in the storage step, a ratio (S5 / S4) of a contact area (S5) of the liquid surface with a gas phase to a horizontal cross-sectional area (S4) of the container at the height of the liquid surface is less than 0.3. [8] The method for producing a cleaning composition described in [6] or [7], wherein the storage step is carried out with a float installed to cover at least a portion of the liquid surface. [9] The method for producing a cleaning composition described in [8], wherein, in the storage step, a ratio (S6 / S4) of the horizontal cross-sectional area (S6) of the float at the height of the liquid level to the horizontal cross-sectional area (S4) of the container at the height of the liquid level is 0.7 or more.

[10] The method for producing a cleaning composition according to any one of [6] to [9], wherein the container is stored under an air atmosphere.

[11] The method for producing a cleaning composition according to any one of [1] to

[10] , wherein the organic solvent is an aprotic solvent.

[12] The method for producing a cleaning composition according to

[11] , wherein at least one of the aprotic solvents is (A) an N,N-disubstituted amide compound.

[13] The (A) N,N-disubstituted amide compound has the formula (1): [ka] (In formula (1), R 1 represents an alkyl group having 1 to 4 carbon atoms. The method for producing the cleaning composition according to

[12] , wherein the 2-pyrrolidone derivative compound is represented by the following formula:

[14] The method for producing a cleaning composition according to any one of

[11] to

[13] , wherein at least one of the aprotic solvents (B) is an ether compound.

[15] The (B) ether compound is represented by the formula (2): R 2 O(C n H2n O) x R 3 (2) (In formula (2), R 2 and R 3 each independently represents an alkyl group selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group, n is 2 or 3, and x is an integer from 1 to 4. The method for producing the cleaning composition according to

[14] , which contains a dialkyl ether of a glycol represented by the formula:

[16] The (B) ether compound is represented by the formula (3): R 4 OR 5 (3) (In the formula, R 4 and R 5 each independently represents an alkyl group having 4 to 8 carbon atoms. A method for producing the cleaning composition according to

[14] or

[15] , which contains a dialkyl ether represented by the formula:

[17] The quaternary alkyl ammonium fluoride is R 6 R 7 R 8 R 9 N + F - R is a tetraalkylammonium fluoride represented by the formula 6 ~R 9 wherein each independently represents an alkyl group selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group.

[18] The method for producing a cleaning composition according to any one of [1] to

[17] , wherein the content of the quaternary alkylammonium fluoride is 0.01 to 10 mass% relative to 100 mass% of the cleaning composition.

[19] The method for producing a cleaning composition according to any one of [1] to

[18] , wherein the cleaning composition is an adhesive polymer cleaning composition.

[20] The method for producing a cleaning composition according to

[19] , wherein the adhesive polymer is a polyorganosiloxane compound. Effect of the Invention

[0017] According to the method for producing a cleaning composition of the present disclosure, a cleaning composition having a high etching rate can be produced even in a normal air atmosphere without using an inert gas.

[0018] The above description should not be considered as a disclosure of all embodiments of the present invention and all advantages associated with the present invention. [Brief description of the drawings]

[0019] [Figure 1A] 1A and 1B are schematic diagrams (side view and top view) of a first embodiment. [Figure 1B] 1A and 1B are schematic diagrams (side view and top view) of a first embodiment. [Figure 2A] 1A and 1B are schematic diagrams (side view and top view) of a second embodiment. [Figure 2B] 1A and 1B are schematic diagrams (side view and top view) of a second embodiment. [Figure 3A] 13 is a schematic diagram (side view and top view) of a third embodiment. [Figure 3B] 13 is a schematic diagram (side view and top view) of a third embodiment. [Figure 4] 1 is a graph plotting ER in the cleaning test of the examples versus the water concentration of the cleaning composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The present invention will be described in further detail below. Note that the present invention is not limited to the following embodiments.

[0021] In this specification, when "to" is used to describe a numerical range, the numerical values ​​at both ends are the upper and lower limits, respectively, and are included in the numerical range.

[0022] In this specification, "horizontal cross-sectional area" means the cross-sectional area in a plane parallel to the liquid surface.

[0023] [Method of manufacturing cleaning composition] (Preparation process) The cleaning composition is prepared by mixing the quaternary alkyl ammonium fluoride or its hydrate and the organic solvent in a state in which at least a part of the liquid surface of a mixing tank containing the quaternary alkyl ammonium fluoride or its hydrate and the organic solvent is shielded from the gas phase. By shielding at least a part of the liquid surface of the mixing tank from the gas phase during mixing, it is possible to suppress contact between the cleaning composition and the gas phase, usually air, compared to when it is not shielded.

[0024] In the preparation step, the ratio (S2 / S1) of the contact area (S2) of the liquid surface with the gas phase to the horizontal cross-sectional area (S1) of the mixing vessel at the height of the liquid surface is preferably less than 0.3, more preferably less than 0.2, even more preferably less than 0.10, and particularly preferably less than 0.05. From the viewpoint of suppressing contact between the cleaning composition and air, the smaller the ratio (S2 / S1) of the contact area (S2) of the liquid surface with the gas phase to the horizontal cross-sectional area (S1) of the mixing vessel at the height of the liquid surface, the more preferable, and the lower limit is not particularly limited, but may be, for example, 0 or more, or 0.01 or more. Any combination of these lower limit values ​​and upper limit values ​​may be used.

[0025] An example of a method for isolating at least a part of the liquid surface in the mixing vessel from the gas phase is to install a float that covers at least a part of the liquid surface. When mixing in the mixing vessel is performed using an impeller, the liquid surface does not exist in the area occupied by the impeller shaft.

[0026] The float may be a single float or multiple small floats. When a single float is used, it is preferable to use a float having a contact surface with approximately the same shape as the liquid surface of the mixing tank. When multiple small floats are used, for example, multiple small floats having a contact surface smaller than the liquid surface of the mixing tank can be laid on the liquid surface. In this case, the layer formed by the multiple small floats may be a single layer or multiple layers. In other words, the small floats may be stacked on top of each other.

[0027] In the preparation step, the ratio (S3 / S1) of the horizontal cross-sectional area (S3) of the float at the height of the liquid level to the horizontal cross-sectional area (S1) of the mixing tank at the height of the liquid level is preferably 0.7 or more, more preferably 0.8 or more, even more preferably 0.9 or more, and particularly preferably 0.95 or more. From the viewpoint of suppressing contact between the cleaning composition and air, the ratio (S3 / S1) of the horizontal cross-sectional area (S3) of the float at the height of the liquid level to the horizontal cross-sectional area (S1) of the mixing tank at the height of the liquid level is preferably closer to 1, and the upper limit is not particularly limited, but may be, for example, 1.00 or less, or 0.99 or less. Any combination of these lower limit values ​​and upper limit values ​​may be used. When multiple small floats are used, the horizontal cross-sectional area (S3) of the float at the height of the liquid level is the sum of the horizontal cross-sectional areas of all the small floats at the height of the liquid level.

[0028] The float is not particularly limited as long as it floats on the liquid surface of the mixing tank and does not react with the cleaning composition. Specific examples thereof include a low-density solid body, a hollow body, and a cup with an open top. The cross-sectional shape of the cup is not particularly limited and may be any shape. When the float is a hollow body, the contents of the hollow body include, for example, air and an inert gas, and preferably an inert gas. The inert gas is preferably argon gas or nitrogen gas, and more preferably nitrogen gas. When the hollow body used as the float is made of, for example, resin, it is slightly permeable to oxygen, so that the permeation of oxygen can be suppressed by sealing an inert gas in the hollow body. When the float is a cup with an open top, it is preferable to face the opening toward the top of the mixing tank so that the bottom of the cup comes into contact with the cleaning composition.

[0029] Examples of the material of the float include resin, glass, metal (e.g., SUS), etc. Resin is preferable because the float is likely to float on the liquid surface. Glass and metal are preferable from the viewpoint of suppressing gas permeation through the float.

[0030] When a single float is used, any shape of float can be used, but as described above, it is preferable to use a float having a contact surface with approximately the same shape as the liquid surface of the mixing tank. The height of the float is not particularly limited. That is, the float may be contained inside the mixing tank or may protrude from the top of the mixing tank. When multiple small floats are used, the shape of the small float is not particularly limited, and examples include a spherical shape, a hexagonal shape, and a cubic shape. The shapes of the multiple small floats may all be the same or may be different from each other.

[0031] The mixing method in the mixing tank is not particularly limited, but for example, it can be a method using a stirring bar and a magnetic stirrer, or a method using a stirring blade.When mixing using a stirring blade, a float having a hole through which the stirring blade shaft passes can be used, or a plurality of small floats can be laid around the stirring blade shaft.When using a float having a hole through which the stirring blade shaft passes, there can be a gap between the stirring blade shaft and the float, but from the viewpoint of suppressing the contact between the cleaning composition and air, the smaller the gap, the more preferable, and it is more preferable that the stirring blade shaft and the float are in close contact with each other.

[0032] When mixing in a mixing vessel is performed using an impeller with a float installed to cover at least a part of the liquid surface, S1 is expressed as "S1 = S2 + S3 + (cross-sectional area of ​​the impeller shaft at the height of the liquid surface)." When there is no object other than the float on the liquid surface in the mixing vessel, S1 is expressed as "S2 + S3."

[0033] The mixing tank may be placed under an inert gas atmosphere or an air atmosphere. From the viewpoint of simplifying the production equipment and safety, it is preferable to place the mixing tank under an air atmosphere. The inert gas is preferably argon gas or nitrogen gas, and more preferably nitrogen gas.

[0034] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[0035] <First embodiment> The first embodiment is an embodiment using a single float and impeller. The float may be, for example, a solid body, a hollow body, or a cup with an open top, having a hole through which the impeller shaft passes.

[0036] As an example, FIG. 1A shows schematic diagrams (side view and top view) of an embodiment using a solid or hollow body having a hole through which the shaft of the impeller passes and an impeller. In FIG. 1A, the float 1 is a solid or hollow body. In FIG. 1A, the mixing vessel 2 contains quaternary alkylammonium fluoride or its hydrate 3 and an organic solvent 4 and is equipped with an impeller 5, and the liquid surface of the mixing vessel 2 is covered with the float 1. The liquid surface of the mixing vessel 2 is blocked from the gas phase by the float 1. In FIG. 1A, the float 1 is contained in the mixing vessel 2, but the float 1 may protrude from the top of the mixing vessel 2.

[0037] As a modified example, a cup having a hole through which the shaft of the stirring blade passes and a schematic diagram (side view and top view) of an embodiment using the stirring blade are shown in FIG. 1B. In FIG. 1B, the float 1 is a cup having a hole through which the shaft of the stirring blade passes. In FIG. 1B, the mixing tank 2 contains a quaternary alkyl ammonium fluoride or its hydrate 3 and an organic solvent 4 and is equipped with a stirring blade 5, and the liquid surface of the mixing tank 2 is covered with the float 1. The float 1 is installed with an opening facing upward of the mixing tank so that the bottom surface of the cup contacts the cleaning composition. The liquid surface of the mixing tank 2 is blocked from the gas phase by the float 1. In FIG. 1B, the float 1 protrudes from the top of the mixing tank 2, but the float 1 may be contained in the mixing tank 2.

[0038] <Second embodiment> The second embodiment uses a single float, a stirring bar, and a magnetic stirrer. The float may be, for example, a solid body, a hollow body, or a cup with an open top.

[0039] As an example, a schematic diagram (side view and top view) of an embodiment using a solid or hollow body, a stirring bar, and a magnetic stirrer is shown in FIG. 2A. In FIG. 2A, the float 1 is a solid or hollow body. In FIG. 2A, the mixing vessel 2 contains quaternary alkylammonium fluoride or its hydrate 3, an organic solvent 4, and a stirring bar 6 and is placed on a magnetic stirrer 7, and the liquid surface of the mixing vessel 2 is covered with the float 1. The liquid surface of the mixing vessel 2 is blocked from the gas phase by the float 1. In FIG. 2A, the float 1 is contained in the mixing vessel 2, but the float 1 may protrude from the top of the mixing vessel 2.

[0040] As a modified example, a schematic diagram (side view and top view) of an embodiment using an open-topped cup, a stirrer, and a magnetic stirrer is shown in FIG. 2B. In FIG. 2B, the float 1 is a cup with an open top. In FIG. 2B, the mixing tank 2 contains a quaternary alkyl ammonium fluoride or its hydrate 3, an organic solvent 4, and a stirrer 6 and is placed on a magnetic stirrer 7, and the liquid surface of the mixing tank 2 is covered with the float 1. The float 1 is placed with its opening facing upward of the mixing tank so that the bottom of the cup contacts the cleaning composition. The liquid surface of the mixing tank 2 is blocked from the gas phase by the float 1. In FIG. 2B, the float 1 protrudes from the top of the mixing tank 2, but the float 1 may be contained in the mixing tank 2.

[0041] In FIG. 2A and FIG. 2B, instead of using a stirring bar and a magnetic stirrer, stirring in the mixing vessel may be performed using a stirring blade attached inside the mixing vessel.

[0042] <Third embodiment> The third embodiment uses a plurality of small floats. For example, a solid body, a hollow body, or a cup with an open top can be used as the float.

[0043] As an example, a schematic diagram (side view and top view) of an embodiment using multiple small floats and a stirring blade is shown in FIG. 3A. In FIG. 3A, the float 1 is a solid or hollow body. In FIG. 3A, a mixing vessel 2 contains a quaternary alkyl ammonium fluoride or its hydrate 3 and an organic solvent 4 and is equipped with a stirring blade 5, and the liquid surface of the mixing vessel 2 is covered with the float 1. The liquid surface of the mixing vessel 2 is blocked from the gas phase by the float 1. In FIG. 3A, the floats 1 are stacked to form multiple layers, but the layer formed may be a single layer.

[0044] As a modified example, a schematic diagram (side view and top view) of an embodiment using a plurality of small floats, a stirrer, and a magnetic stirrer is shown in FIG. 3B. In FIG. 3B, the float 1 is a solid or hollow body. In FIG. 3B, the mixing vessel 2 contains a quaternary alkyl ammonium fluoride or its hydrate 3, an organic solvent 4, and a stirrer 6 and is placed on a magnetic stirrer 7, and the liquid surface of the mixing vessel 2 is covered with the float 1. The liquid surface of the mixing vessel 2 is blocked from the gas phase by the float 1. In FIG. 3B, the floats 1 are stacked to form a plurality of layers, but the layer formed may be a single layer.

[0045] In FIG. 3B, instead of using a stirring bar and a magnetic stirrer, stirring in the mixing vessel may be performed using a stirring blade attached inside the mixing vessel.

[0046] (Storage process) After the preparation step, it is preferable to store the cleaning composition in a state where at least a part of the liquid surface of the container containing the prepared cleaning composition is isolated from the gas phase. By blocking at least a part of the liquid surface of the container from the gas phase during storage, it is possible to suppress contact between the cleaning composition and the gas phase, usually air, compared to when it is not blocked.

[0047] In the storage step, the container in which the cleaning composition is stored may be the same as or different from the mixing tank in the preparation step. When the container in which the cleaning composition is stored is different from the mixing tank in the preparation step, the cleaning composition may be transferred from the mixing tank to a container for storage. The operation of transferring the cleaning composition to a container for storage may be performed under an inert gas atmosphere or under an air atmosphere.

[0048] In the storage step, the ratio (S5 / S4) of the contact area (S5) of the liquid surface with the gas phase to the horizontal cross-sectional area (S4) of the container at the height of the liquid surface is preferably less than 0.3, more preferably less than 0.2, even more preferably less than 0.10, and particularly preferably less than 0.05. From the viewpoint of suppressing contact between the cleaning composition and air, the smaller the ratio (S5 / S4) of the contact area (S5) of the liquid surface with the gas phase to the horizontal cross-sectional area (S4) of the container at the height of the liquid surface, the more preferable, and the lower limit is not particularly limited, but may be, for example, 0 or more, or 0.01 or more. Any combination of these lower limit values ​​and upper limit values ​​may be used.

[0049] An example of a method for blocking at least a portion of the liquid surface in the container from the gas phase is to provide a float that covers at least a portion of the liquid surface.

[0050] The preferred embodiment of the float is the same as that of the float in the preparation step, and the "mixing tank" in the preparation step may be read as the "container" in the storage step. However, since the stirring blade is not used in the storage step, it is preferred that the float does not have a hole through which the shaft of the stirring blade passes.

[0051] In the storage step, the ratio (S6 / S4) of the horizontal cross-sectional area (S6) of the float at the height of the liquid level to the horizontal cross-sectional area (S4) of the container at the height of the liquid level is preferably 0.7 or more, more preferably 0.8 or more, even more preferably 0.9 or more, and particularly preferably 0.95 or more. From the viewpoint of suppressing contact between the cleaning composition and air, the ratio (S6 / S4) of the horizontal cross-sectional area (S6) of the float at the height of the liquid level to the horizontal cross-sectional area (S4) of the container at the height of the liquid level is preferably closer to 1, and the upper limit is not particularly limited, but may be, for example, 1.00 or less, or 0.99 or less. Any combination of these lower limit values ​​and upper limit values ​​may be used. When multiple small floats are used, the horizontal cross-sectional area (S6) of the float at the height of the liquid level is the sum of the horizontal cross-sectional areas of all the small floats at the height of the liquid level.

[0052] The storage container may be placed under an inert gas atmosphere or under an air atmosphere. From the viewpoint of simplifying the storage facility and for safety, it is preferable to place the container under an air atmosphere. The inert gas is preferably argon gas or nitrogen gas, and more preferably nitrogen gas.

[0053] (Other processes) After the preparation step, instead of the above-mentioned storage step, a step of replacing the inside of the container containing the prepared cleaning composition with an inert gas and sealing the container (hereinafter, sometimes referred to as a "sealing step" may be performed. By performing the sealing step, the contact between the prepared cleaning composition and air can be more effectively suppressed. Therefore, when the prepared cleaning composition is stored for a long period of time, it is preferable to perform the sealing step. The inert gas is preferably argon gas or nitrogen gas, and more preferably nitrogen gas.

[0054] In the sealing step, the container in which the cleaning composition is stored may be the same as or different from the mixing tank in the preparation step. When the container in which the cleaning composition is stored is different from the mixing tank in the preparation step, the cleaning composition may be transferred from the mixing tank to a storage container. The operation of transferring the cleaning composition to a storage container is preferably performed under an inert gas atmosphere.

[0055] [Cleaning composition] The cleaning composition of one embodiment contains a quaternary alkyl ammonium fluoride or a hydrate thereof, and an organic solvent.

[0056] <Quaternary alkyl ammonium fluoride or its hydrate> Quaternary alkylammonium fluoride or its hydrate releases fluoride ions that are involved in the cleavage of Si-O bonds. The quaternary alkylammonium moiety allows the salt quaternary alkylammonium fluoride to dissolve in an organic solvent. As the quaternary alkylammonium fluoride, various compounds can be used without particular limitation. Hydrates of quaternary alkylammonium fluoride include, for example, trihydrate, tetrahydrate, and pentahydrate. The quaternary alkylammonium fluoride may be one type or a combination of two or more types. The non-hydrate and hydrate of quaternary alkylammonium fluoride can be used in any ratio.

[0057] In one embodiment, the quaternary alkyl ammonium fluoride is R 6 R 7 R 8 R 9 N + F - R is a tetraalkylammonium fluoride represented by the formula 6 ~R 9 are each independently an alkyl group selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group. 6 ~R 9are preferably all the same alkyl group. Examples of such quaternary alkyl ammonium fluoride include tetramethylammonium fluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride, and tetrabutylammonium fluoride. From the viewpoints of decomposition and cleaning performance, availability, and price, the quaternary alkyl ammonium fluoride is preferably tetrabutylammonium fluoride (TBAF).

[0058] In one embodiment, the content of the quaternary alkyl ammonium fluoride in the cleaning composition is 0.01 to 10% by mass. Here, the "content of the quaternary alkyl ammonium fluoride" is a value calculated as the mass of only the quaternary alkyl ammonium fluoride excluding the mass of the hydrate of the quaternary alkyl ammonium fluoride when the composition contains a hydrate of the quaternary alkyl ammonium fluoride. The content of the quaternary alkyl ammonium fluoride in the cleaning composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more. The content of the quaternary alkyl ammonium fluoride in the cleaning composition is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 2% by mass or less, and particularly preferably 1% by mass or less. The combination of these lower limit values ​​and upper limit values ​​may be any combination. In another embodiment, the content of the quaternary alkyl ammonium fluoride in the cleaning composition is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more. In this embodiment, the content of the quaternary alkyl ammonium fluoride in the cleaning composition is preferably 9% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less. Any combination of these lower limit values ​​and upper limit values ​​may be used. By making the content of the quaternary alkyl ammonium fluoride 0.01% by mass or more, the adhesive polymer can be effectively decomposed and cleaned. By making it 10% by mass or less, corrosion of the metal parts included in the device formation surface of the device wafer can be prevented or suppressed.

[0059] When prevention or inhibition of corrosion of metal parts or reduction of costs associated with the use of quaternary alkyl ammonium fluoride is particularly required, the content of quaternary alkyl ammonium fluoride in the cleaning composition may be 4 mass % or less, or 3 mass % or less.When a higher etching rate is required, the content of quaternary alkyl ammonium fluoride in the cleaning composition may be 5 mass % or more, 6 mass % or more, or 7 mass % or more.

[0060] <Organic solvent> The organic solvent is not particularly limited as long as it can dissolve or disperse the quaternary alkyl ammonium fluoride or its hydrate. The organic solvent is preferably an aprotic solvent. The aprotic solvent does not form a solvation with the fluoride ion of the quaternary alkyl ammonium fluoride via hydrogen bonds, and therefore can increase the reactivity of the fluoride ion. Examples of the aprotic solvent include N,N-disubstituted amide compounds such as N-methylpyrrolidone (NMP) and N,N-dimethylformamide (DMF); ether compounds such as dipropylene glycol dimethyl ether and dibutyl ether; and organic sulfur oxides such as dimethyl sulfoxide (DMSO) and sulfolane.

[0061] The content of the organic solvent relative to 100% by mass of the cleaning composition is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. The content of the organic solvent relative to 100% by mass of the cleaning composition is preferably 99.99% by mass or less, more preferably 99.95% by mass or less, and even more preferably 99.90% by mass or less. Any combination of these lower and upper limits may be used.

[0062] The content of the aprotic solvent relative to 100% by mass of the cleaning composition is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. The content of the aprotic solvent relative to 100% by mass of the cleaning composition is preferably 99.99% by mass or less, more preferably 99.95% by mass or less, and even more preferably 99.90% by mass or less. Any combination of these lower and upper limits may be used.

[0063] The content of the aprotic solvent relative to 100% by mass of the organic solvent is preferably 95 to 100% by mass, more preferably 98 to 100% by mass, and further preferably 100% by mass.

[0064] The organic solvent preferably contains at least one aprotic solvent selected from the group consisting of (A) N,N-disubstituted amide compounds and (B) ether compounds.

[0065] In one embodiment, the organic solvent is substantially free or free of aprotic solvents selected from ketones and esters. For example, the cleaning composition may contain no more than 1.0% by weight, no more than 0.5% by weight, or no more than 0.1% by weight of aprotic solvents selected from ketones and esters.

[0066] ((A) N,N-disubstituted amide compounds) The organic solvent preferably contains an N,N-disubstituted amide compound as an aprotic solvent. The N,N-disubstituted amide compound is an amide compound in which a hydrogen atom is not directly bonded to the nitrogen atom. The N,N-disubstituted amide compound is an aprotic solvent with relatively high polarity, and can uniformly dissolve or disperse the quaternary alkyl ammonium fluoride and its hydrate in the composition. In the present disclosure, the "N,N-disubstituted amide compound" also includes a urea compound (carbamide compound) in which a hydrogen atom is not directly bonded to the nitrogen atom. As the N,N-disubstituted amide compound, various compounds can be used without any particular limitation, for example, non-cyclic amides such as N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylpropionamide, N,N-diethylpropionamide, tetramethylurea, and cyclic amides such as 2-pyrrolidone derivatives, 2-piperidone derivatives, ε-caprolactam derivatives, 1,3-dimethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (N,N'-dimethylpropyleneurea). Among these, it is preferable to use cyclic amides. The N,N-disubstituted amide compound may be one type or a combination of two or more types.

[0067] In one embodiment, the N,N-disubstituted amide compound has the formula (1): [ka] (In formula (1), R 1 represents an alkyl group having 1 to 4 carbon atoms. The 2-pyrrolidone derivative compound represented by formula (1) is represented by the formula (1). Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group. Examples of the 2-pyrrolidone derivative compound represented by formula (1) include N-methylpyrrolidone, N-ethylpyrrolidone, N-propylpyrrolidone, and N-butylpyrrolidone.

[0068] N,N-disubstituted amide compounds are preferred because of their relatively high polarity, excellent dissolving ability for quaternary alkylammonium fluorides, and ease of availability. 1 is preferably a 2-pyrrolidone derivative compound in which R 1 More preferably, it is a 2-pyrrolidone derivative compound in which is a methyl group, that is, N-methylpyrrolidone.

[0069] The content of the N,N-disubstituted amide compound is preferably 20 to 100 mass%, more preferably 30 to 90 mass%, further preferably 35 to 85 mass%, and particularly preferably 40 to 80 mass%, when the organic solvent is taken as 100 mass%.

[0070] ((B) Ether Compounds) The organic solvent preferably contains an ether compound as an aprotic solvent, and more preferably contains an ether compound and an N,N-disubstituted amide compound. By combining an ether compound with an N,N-disubstituted amide compound, a mixed solvent system showing high affinity to the adhesive surface can be formed. A composition using such a mixed solvent system can achieve a high etching rate by effectively utilizing the reaction activity of quaternary alkyl ammonium fluoride. As the ether compound, various compounds can be used without particular limitation as long as they are aprotic solvents. The ether compound may be one type or a combination of two or more types. The ether compound is preferably one that does not contain an ester structure or an amide structure.

[0071] In one embodiment, the ether compound has the formula (2): R 2 O(C n H 2n O) x R 3 (2) (In formula (2), R 2 and R 3each independently represents an alkyl group selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group, n is 2 or 3, and x is an integer from 1 to 4. The dialkyl ethers of glycols represented by the formula:

[0072] Examples of the dialkyl ether of glycol represented by formula (2) include ethylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol di-n-butyl ether, tetraethylene glycol dimethyl ether, tetrapropylene glycol dimethyl ether, etc. The dialkyl ether of glycol represented by formula (2) is preferably diethylene glycol dimethyl ether or dipropylene glycol dimethyl ether from the viewpoints of decomposition and cleaning performance, availability, price, etc., and more preferably dipropylene glycol dimethyl ether because a high etching rate can be obtained over a wide range of compositions.

[0073] The content of the dialkyl ether of the glycol represented by formula (2) is preferably 10 to 80 mass%, more preferably 15 to 70 mass%, and even more preferably 20 to 60 mass%, based on 100 mass% of the organic solvent. In another embodiment, the content of the dialkyl ether of the glycol represented by formula (2) is preferably 0 to 60 mass%, more preferably 3 to 50 mass%, and even more preferably 5 to 40 mass%, based on 100 mass% of the organic solvent.

[0074] In one embodiment, the ether compound has the formula (3): R 4 OR 5 (3) (In the formula, R 4 and R 5each independently represents an alkyl group having 4 to 8 carbon atoms. The dialkyl ethers include those represented by the formula:

[0075] The ether compound may contain a dialkyl ether of a glycol represented by formula (2) and a dialkyl ether represented by formula (3). By using two or more types of ether compounds having different polarities in combination, it is possible to effectively increase the affinity for various adhesive surfaces and obtain a composition with a wide range of applications.

[0076] Examples of the dialkyl ether represented by formula (3) include dibutyl ether, dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, butylhexyl ether, butyloctyl ether, etc. The dialkyl ether represented by formula (3) is preferably dibutyl ether from the viewpoints of decomposition and cleaning performance, availability, price, etc.

[0077] The content of the dialkyl ether represented by formula (3) is preferably 0 to 50 mass%, more preferably 1 to 35 mass%, and even more preferably 2 to 30 mass%, when the organic solvent is taken as 100 mass%. By setting the content of the dialkyl ether represented by formula (3) to 0 mass% or more and 50 mass% or less, a higher etching rate can be obtained. In another embodiment, the content of the dialkyl ether represented by formula (3) is preferably 30 to 70 mass%, more preferably 35 to 65 mass%, and even more preferably 40 to 60 mass%, when the organic solvent is taken as 100 mass%.

[0078] In one embodiment, the flash point of the ether compound is 21° C. or higher. By using an ether compound having a flash point of 21° C. or higher, i.e., not falling under the category of Class 4 Hazardous Substances, Class 1 Petroleum, the requirements for equipment, working environment, etc. in the production and use of the composition can be reduced compared to the case of using tetrahydrofuran (THF, flash point -17° C., Class 4 Hazardous Substances, Class 1 Petroleum) or the like. For example, the flash points of diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, and dibutyl ether are 51° C., 60° C., and 25° C., respectively. The flash point is measured by the tag-closed method (JIS K 2265-1:2007).

[0079] (Composition ratio of N,N-disubstituted amide compound and ether compound) In one embodiment, when the organic solvent is taken as 100% by mass, the content of the N,N-disubstituted amide compound is 10 to 90% by mass, and the content of the ether compound is 90 to 10% by mass. When the organic solvent is taken as 100% by mass, the content of the N,N-disubstituted amide compound is preferably 15 to 85% by mass, the content of the ether compound is preferably 85 to 15% by mass, and the content of the N,N-disubstituted amide compound is more preferably 25 to 65% by mass, and the content of the ether compound is more preferably 75 to 35% by mass. In another embodiment, when the organic solvent is taken as 100% by mass, the content of the N,N-disubstituted amide compound is preferably 40 to 80% by mass, and the content of the ether compound is preferably 60 to 20% by mass. By setting the content of the N,N-disubstituted amide compound and the ether compound in the above range, the quaternary alkyl ammonium fluoride and its hydrate can be uniformly dissolved or dispersed in the composition, and a high etching rate can be obtained for various adhesive surfaces.

[0080] In one embodiment, when the organic solvent is taken as 100% by mass, the content of the N,N-disubstituted amide compound is 20 to 90% by mass, the content of the dialkyl ether of the glycol represented by formula (2) is 10 to 80% by mass, and the content of the dialkyl ether represented by formula (3) is 0 to 30% by mass. Preferably, the content of the N,N-disubstituted amide compound is 25 to 80% by mass, the content of the dialkyl ether of the glycol represented by formula (2) is 20 to 60% by mass, and the content of the dialkyl ether represented by formula (3) is 0 to 30% by mass. In another embodiment, when the organic solvent is taken as 100% by mass, the content of the N,N-disubstituted amide compound is 20 to 90% by mass, the content of the dialkyl ether of the glycol represented by formula (2) is 0 to 70% by mass, and the content of the dialkyl ether represented by formula (3) is 0 to 30% by mass. Preferably, the content of the N,N-disubstituted amide compound is 30 to 85 mass%, the content of the dialkyl ether of the glycol represented by formula (2) is 3 to 50 mass%, and the content of the dialkyl ether represented by formula (3) is 0 to 30 mass%. In still another embodiment, when the organic solvent is taken as 100 mass%, the content of the N,N-disubstituted amide compound is 20 to 80 mass%, the content of the dialkyl ether of the glycol represented by formula (2) is 10 to 50 mass%, and the content of the dialkyl ether represented by formula (3) is 30 to 60 mass%.

[0081] <Additives and other ingredients> The cleaning composition may contain additives such as antioxidants, surfactants, preservatives, and antifoaming agents as optional components, provided that the effects of the present invention are not significantly impaired.

[0082] In one embodiment, the cleaning composition is substantially free of protic solvent or free of protic solvent.For example, the content of protic solvent in the composition can be 5% by weight or less, 3% by weight or less, or 1% by weight or less.The protic solvent that can be included in the composition can be water derived from quaternary alkyl ammonium fluoride hydrate.

[0083] [Method of using the cleaning composition] The composition of the present disclosure can be used as a cleaning composition for adhesive polymers contained in various adhesives. The adhesive polymer is not particularly limited as long as it can be cleaned using the cleaning composition of the present disclosure. In addition to the adhesive polymer, the adhesive may contain optional components such as a curing agent, a curing accelerator, a crosslinking agent, a surfactant, a leveling agent, and a filler.

[0084] In one embodiment, the adhesive polymer contains a Si-O bond. The adhesive polymer is depolymerized or loses its crosslinked structure by cleavage of the Si-O bond by the fluoride ion of the quaternary alkyl ammonium fluoride, and becomes soluble in a solvent, so that the adhesive polymer can be removed from the surface of a device wafer or the like.

[0085] The adhesive polymer containing Si-O bonds is preferably a polyorganosiloxane compound. Since the polyorganosiloxane compound contains a large number of siloxane (Si-O-Si) bonds, it can be effectively decomposed and cleaned using a cleaning composition. Examples of the polyorganosiloxane compound include silicone resins such as silicone elastomers, silicone gels, and MQ resins, as well as modified versions thereof such as epoxy modified, acrylic modified, methacrylic modified, amino modified, and mercapto modified. The polyorganosiloxane compound may be a silicone modified polymer such as a silicone modified polyurethane or a silicone modified acrylic resin.

[0086] In one embodiment, the adhesive polymer is an addition-cured silicone elastomer, silicone gel, or silicone resin that includes an ethylenically unsaturated polyorganosiloxane, such as a vinyl-terminated polydimethylsiloxane or a vinyl-terminated MQ resin, and a polyorganohydrogensiloxane, such as a polymethylhydrogensiloxane, as a crosslinker, and is cured with a hydrosilylation catalyst, such as a platinum catalyst.

[0087] In another embodiment, the adhesive polymer includes an aralkyl group, an epoxy group, or a polydiorganosiloxane containing a phenyl group, particularly a polydimethylsiloxane containing an aralkyl group, an epoxy group, or a phenyl group. An adhesive containing such an adhesive polymer may be used for temporary adhesion in combination with the above addition-curing silicone adhesive.

Examples

[0088] Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited by the Examples.

[0089] (Example 1) <Weighing of TBAF·3H2O and Charging of Reagent into Beaker> A 100 mL glass beaker (inner diameter 50.80 mm) was placed in a simple glove box, and the inside of the glove box was sufficiently replaced with dry air. At this time, when the temperature and humidity inside the glove box were measured with a digital thermometer / hygrometer CHE-TP1 manufactured by Sanwa Supply Co., Ltd., they were 22.8 °C and 18.6% RH (relative humidity). 5.606 g of tetrabutylammonium fluoride trihydrate (TBAF·3H2O) (98%) was charged into this beaker. Next, 41.573 g of N-methyl-2-pyrrolidone (NMP), 4.125 g of dipropylene glycol dimethyl ether (DPGDME), and 7.837 g of dibutyl ether (DBE) were charged in this order. At this time, the undissolved TBAF·3H2O was floating in the solvent. A stirrer chip with a length of 20 mm was charged here.

[0090] <Installation of Float Covering Liquid Surface> Nitrogen gas was sealed in a 125 mL PE container (Nalgene bottle, Thermo Fisher Scientific, outer diameter 50.00 mm), and then the container was slowly dropped into a beaker with the bottom facing down. Air was discharged from the gap between the beaker and the PE container, and the PE container was floating on the liquid. In this way, by using the PE container as a float, at least a part of the liquid surface of the beaker was blocked from the gas phase. This allowed the contact area between the liquid surface and the air in the beaker to be significantly reduced. At this time, the ratio (S3 / S1) of the horizontal cross-sectional area (S3) of the float to the horizontal cross-sectional area (S1) of the beaker at the height of the liquid surface was 0.968, and the ratio (S2 / S1) of the contact area (S2) of the liquid surface with the gas phase to the horizontal cross-sectional area (S1) of the beaker at the height of the liquid surface was 0.032. In other words, the contact area between the air and the cleaning composition could be 3.2%, assuming that the case where the float is not installed is 100%.

[0091] <Preparation process> Next, the beaker with the float was taken out of the simplified glove box, that is, into a normal room air atmosphere. At this time, the room temperature and humidity measured with the thermometer and hygrometer were 23.0°C and 65.3%RH. The beaker was placed on a magnetic stirrer and stirred at 400 rpm for 180 minutes to dissolve the TBAF·3H2O. The time from taking it out of the glove box to starting stirring was within 2 minutes. In this way, a cleaning composition (TBAF content: 7.7% by mass) of a mixed solvent with a mass ratio of NMP:DPGDME:DBE of 0.777:0.077:0.146 was prepared.

[0092] <Sampling of cleaning compositions> Sampling of the prepared cleaning composition was carried out in a simple glove box filled with nitrogen gas to prevent the entire liquid surface of the cleaning composition from coming into contact with air. The beaker containing the cleaning composition after stirring for 180 minutes and three 50 mL glass sample bottles were placed in a simple glove box under a nitrogen gas atmosphere. The float was lifted to collect 15 mL of the cleaning composition in each glass sample bottle, and the lids of the glass sample bottles were closed.

[0093] <Preparation of silicon wafer test piece having adhesive layer containing polyorganosiloxane compound> An addition-curing silicone resin was applied by spin coating onto a 12-inch (300 mm) silicon wafer (thickness 770 μm) so that the dry film thickness was 110 μm. The silicon wafer was then heated on a hot plate at 140° C. for 15 minutes and at 190° C. for 10 minutes to form an adhesive layer on the silicon wafer. The silicon wafer with the adhesive layer was divided into test pieces measuring 1 cm x 1 cm, and the thickness of the center of the test piece was measured using a micrometer.

[0094] <Cleaning test> One of the 50 mL glass sample bottles containing the cleaning composition was removed from the glove box and placed in a thermostatic bath at 25°C for 30 minutes to set the temperature of the cleaning composition to 25°C. The glass sample bottle was removed from the thermostatic bath, and a stir bar was placed on a magnetic stirrer. One adhesive-attached silicon wafer test piece measuring 1 cm x 1 cm square was immersed in the cleaning composition, and the stir bar was rotated at 900 rpm for 3 minutes. After immersion, the test piece was removed with tweezers and thoroughly rinsed using a washing bottle of isopropyl alcohol (IPA). After drying the test piece by spraying nitrogen gas, the thickness of the center of the test piece was measured using a micrometer. The etching rate (ER) of the cleaning composition was calculated by dividing the difference in thickness of the test piece before and after immersion by the immersion time (3 minutes) in the cleaning composition, as shown in the following formula. Etching rate (ER) (μm / min) = [(thickness of test piece before immersion - thickness of test piece after immersion, washing and drying) (μm)] / immersion time (min)

[0095] The remaining two glass sample bottles in the glove box were subjected to cleaning tests in the same manner, and the ER of the cleaning composition was calculated. The median ER calculated in three cleaning tests is shown in Table 1.

[0096] <Measurement of moisture concentration> The cleaning composition was collected in a 20 mL glass sample bottle in the same manner as in the above-mentioned cleaning composition sampling. The water concentration of this cleaning composition was measured using a Karl Fischer moisture meter (MKC-710, manufactured by Kyoto Electronics Manufacturing Co., Ltd.). The measurement results are shown in Table 1.

[0097] Example 2 The procedure was the same as in Example 1, except that the inner diameter of the beaker used was 50.70 mm, and a Teflon container (outer diameter 45.50 mm) with an open top was used as a float. The median ER and water concentration measurements calculated in three cleaning tests are shown in Table 1.

[0098] Comparative Example 1 In a simple glove box, TBAF·3H2O, NMP, DPGDME, and DBE were placed in a 100 mL glass beaker (inner diameter 50.40 mm) in the same procedure and amounts as in Example 1, and a stirrer tip with a length of 20 mm was further placed in the beaker. At this time, the temperature and humidity of the dry air in the glove box were 23.4°C and 12.9% RH. The beaker without the float was taken out of the simple glove box and placed on a magnetic stirrer, and TBAF·3H2O was dissolved by stirring at 400 rpm for 30 minutes. In this way, a cleaning composition (TBAF content: 7.7 mass%) of a mixed solvent with a mass ratio of NMP:DPGDME:DBE of 0.777:0.077:0.146 was prepared. The temperature and humidity of the air atmosphere during stirring were 23.8°C and 69.0% RH.

[0099] Sampling of the cleaning composition, preparation of silicon wafer test pieces, cleaning tests, and measurement of water concentration were performed in the same manner as in Example 1. The median ER calculated in three cleaning tests and the measurement results of water concentration are shown in Table 1.

[0100] Comparative Example 2 The procedure was the same as in Comparative Example 1, except that a 100 mL glass beaker (inner diameter 50.90 mm) was used and the mixing time was 60 minutes. The median ER and water concentration measurements calculated from three cleaning tests are shown in Table 1.

[0101] Comparative Example 3 The procedure was the same as in Comparative Example 1, except that a 100 mL glass beaker (inner diameter 50.75 mm) was used and the mixing time was 180 minutes. The median ER and water concentration measurements calculated from three cleaning tests are shown in Table 1.

[0102] (Reference example) A 100 mL glass beaker (inner diameter 50.75 mm) was placed in a simple glove box, and the atmosphere in the glove box was thoroughly replaced with nitrogen gas. The temperature and humidity in the glove box were measured using a digital thermo-hygrometer CHE-TP1 manufactured by Sanwa Supply Co., Ltd., and were found to be 22.4°C and <5% RH.

[0103] In a simple glove box, TBAF·3H2O, NMP, DPGDME, DBE, and a 20 mm long stirrer tip were placed in a beaker in the same procedure and amounts as in Example 1, and the top of the beaker was covered with aluminum foil and sealed to prevent the solvent from volatilizing. The beaker was placed on a magnetic stirrer in a glove box with a nitrogen gas atmosphere, and TBAF·3H2O was dissolved by stirring at a rotation speed of 400 rpm for 180 minutes. In this way, a cleaning composition (TBAF content: 7.7 mass%) of a mixed solvent with a mass ratio of NMP:DPGDME:DBE of 0.777:0.077:0.146 was prepared.

[0104] Sampling of the cleaning composition was also carried out under a nitrogen gas atmosphere. In this manner, the weighing and charging of the raw materials, mixing, and sampling were all carried out under a nitrogen gas atmosphere, so that the cleaning composition was prepared without contact with the outside air.

[0105] The preparation of silicon wafer test pieces, cleaning tests, and measurements of moisture concentration were performed in the same manner as in Example 1. The median ER calculated in three cleaning tests and the measurement results of moisture concentration are shown in Table 1.

[0106] [Table 1]

[0107] As shown in Table 1, the cleaning compositions of Examples 1 and 2, which used a float during preparation, gave a higher ER in the cleaning test compared to the cleaning compositions of Comparative Examples 1 to 3, which did not use a float during preparation. Comparing the cleaning compositions of Examples 1 and 2 and the cleaning composition of Comparative Example 3, which had the same mixing time during preparation, it was found that the ER was significantly reduced when a float was not used during preparation. The cleaning composition of Example 1, although prepared under an air atmosphere, gave a high ER equivalent to that of the cleaning composition of the Reference Example prepared under a nitrogen gas atmosphere. This shows that a cleaning composition that gives a high ER can be obtained by using a float during preparation under an air atmosphere.

[0108] A graph in which the ER in the cleaning test is plotted against the water concentration of the cleaning composition is shown in Figure 4. Figure 4 shows that there is a correlation between the water concentration of the cleaning composition and the ER in the cleaning test. It is presumed that when the cleaning composition is prepared in an air atmosphere without using a float, the activity of the fluoride ion decreases because the water contained in the air is mixed into the cleaning composition, and the ER decreases. [Explanation of symbols]

[0109] 1 Float 2 Mixing tank 3. Quaternary alkyl ammonium fluoride or its hydrate 4. Organic Solvents 5 Mixing blade 6 Stirring bar 7 Magnetic Stirrer

Claims

1. A method for producing a cleaning composition containing a quaternary alkylammonium fluoride or a hydrate thereof and an organic solvent, comprising the steps of: The method for producing a cleaning composition includes a preparation step of mixing the quaternary alkylammonium fluoride or hydrate thereof, and the organic solvent in a mixing tank containing the quaternary alkylammonium fluoride or hydrate thereof, and the organic solvent, while blocking at least a part of the liquid surface of the mixing tank from a gas phase.

2. 2. The method for producing a cleaning composition according to claim 1, wherein in the preparation step, a ratio (S2 / S1) of a contact area (S2) of the liquid surface with a gas phase to a horizontal cross-sectional area (S1) of the mixing tank at the height of the liquid surface is less than 0.

3.

3. The method for producing a cleaning composition according to claim 1 , wherein the preparation step is carried out in a state where a float is installed so as to cover at least a part of the liquid surface.

4. 4. The method for producing a cleaning composition according to claim 3, wherein in the preparation step, a ratio (S3 / S1) of a horizontal cross-sectional area (S3) of the float at the height of the liquid level to a horizontal cross-sectional area (S1) of the mixing tank at the height of the liquid level is 0.7 or more.

5. The method for producing a cleaning composition according to any one of claims 1 to 4, wherein the preparation step is carried out in an air atmosphere in the mixing tank.

6. The method for producing a cleaning composition according to any one of claims 1 to 4, further comprising, after the preparation step, a storage step of storing the cleaning composition in a state in which at least a part of a liquid surface of a container containing the prepared cleaning composition is isolated from a gas phase.

7. 7. The method for producing a cleaning composition according to claim 6, wherein in the storage step, a ratio (S5 / S4) of a contact area (S5) of the liquid surface with a gas phase to a horizontal cross-sectional area (S4) of the container at the height of the liquid surface is less than 0.

3.

8. The method for producing a cleaning composition according to claim 6 , wherein the storing step is carried out in a state where a float is installed so as to cover at least a part of the liquid surface.

9. 9. The method for producing a cleaning composition according to claim 8, wherein in the storage step, a ratio (S6 / S4) of a horizontal cross-sectional area (S6) of the float at the height of the liquid level to a horizontal cross-sectional area (S4) of the container at the height of the liquid level is 0.7 or more.

10. The method for producing a cleaning composition according to claim 6, wherein the container is stored under an air atmosphere.

11. The method for producing a cleaning composition according to any one of claims 1 to 4, wherein the organic solvent is an aprotic solvent.

12. The method for producing a cleaning composition according to claim 11, wherein at least one of the aprotic solvents is (A) an N,N-disubstituted amide compound.

13. The (A) N,N-disubstituted amide compound is represented by the formula (1): 【Chemistry 1】 (In formula (1), R １ represents an alkyl group having 1 to 4 carbon atoms. The method for producing a cleaning composition according to claim 12, wherein the 2-pyrrolidone derivative compound is represented by the following formula:

14. The method for producing a cleaning composition according to claim 11, wherein at least one of the aprotic solvents is (B) an ether compound.

15. The (B) ether compound is represented by the formula (2): R ２ O(C ｎ H ２ｎ O) ｘ R ３ (2) (In formula (2), R ２ and R ３ each independently represents an alkyl group selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group, n is 2 or 3, and x is an integer from 1 to 4. A method for making the cleaning composition of claim 14, comprising a dialkyl ether of a glycol represented by the formula:

16. The (B) ether compound is represented by the formula (3): R ４ OR ５ (3) (In the formula, R ４ and R ５ each independently represents an alkyl group having 4 to 8 carbon atoms. A method for producing the cleaning composition of claim 14, comprising a dialkyl ether represented by the formula:

17. The quaternary alkyl ammonium fluoride is R ６ R ７ R ８ R ９ N ＋ F － R is a tetraalkylammonium fluoride represented by the formula: ６ ~R ９ The method for producing a cleaning composition according to any one of claims 1 to 4, wherein each of the alkyl groups is independently selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group.

18. The method for producing a cleaning composition according to any one of claims 1 to 4, wherein the content of the quaternary alkyl ammonium fluoride relative to 100% by mass of the cleaning composition is 0.01 to 10% by mass.

19. The method for producing a cleaning composition according to any one of claims 1 to 4, wherein the cleaning composition is an adhesive polymer cleaning composition.

20. The method of making a cleaning composition according to claim 19, wherein the adhesive polymer is a polyorganosiloxane compound.

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