Composition for protecting copper surface, and method for producing semiconductor intermediate and semiconductor using same

Abstract

Provided is a means for preventing oxidation of a copper surface.　This composition for protecting a copper surface contains a solvent and at least one copper surface protectant selected from the group consisting of compounds represented by formulas (1)-(3) and salts thereof.　[Formula 1]

Description

Copper surface protection composition, and semiconductor intermediate and semiconductor manufacturing method using the same

[0001] The present invention relates to a copper surface protection composition, and a method for manufacturing a semiconductor intermediate and a semiconductor using the same.

[0002] In recent years, electronic devices have become smaller and more functional, and this has led to a demand for smaller and more functional semiconductors.

[0003] Three-dimensional (3D) integration technology has attracted attention as a way to meet the demand for miniaturization and high performance of semiconductors. 3D integration technology involves stacking multiple semiconductor chips or semiconductor wafers with interconnections, and known stacking configurations include Chip to Chip (C2C), Chip to Wafer (C2W), and Wafer to Wafer (W2W).

[0004] As an example of such a 3D integration technology, Patent Document 1 describes an invention relating to a semiconductor structure including a semiconductor layer, an adhesive layer disposed above the semiconductor layer, an anode metal layer disposed above the adhesive layer, and a cathode metal layer disposed above the anode metal layer.

[0005] Patent Document 1 describes that rapid oxide formation on the Cu surface, which inhibits sufficient interconnection, is a major issue in interconnection by Cu-Cu bonding. Patent Document 1 also describes a method for inhibiting Cu oxidation by using a metal (such as Mg) that has a higher oxidation potential than the oxidation potential of Cu, which forms a galvanic couple and sacrifices the Mg itself, thereby inhibiting or reducing Cu oxide growth.

[0006] Japanese Patent Application Laid-Open No. 2020-512703

[0007] Under these circumstances, a new means for preventing oxidation of copper surfaces is required.

[0008] The present invention includes, for example, the following aspects.

[0009] [1] The following formulas (1) to (3): A copper surface protection composition comprising: at least one copper surface protective agent selected from the group consisting of compounds represented by the following formulas (1) to (3): [in which R is a substituted or unsubstituted alkyl group having 3 to 30 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms] and salts thereof; and a solvent. [2] The copper surface protection composition according to [1] above, wherein the copper surface protective agent comprises a compound represented by formula (1) and / or a salt thereof. [3] The copper surface protection composition according to [1] or [2] above, wherein R is a substituted or unsubstituted alkyl group having 3 to 30 carbon atoms. [4] The copper surface protection composition according to any one of [1] to [3] above, further comprising a pH adjuster. [5] The copper surface protection composition according to [4] above, wherein the pH adjuster comprises at least one selected from the group consisting of sodium hydroxide and potassium hydroxide. [6] The copper surface protection composition according to any one of [1] to [5] above, wherein the pH is 2.5 to 5.5. [7] The copper surface protection composition according to any one of [1] to [6] above, which is used in the production of a semiconductor. [8] A method for producing a first semiconductor intermediate comprising a copper-containing layer and a copper surface protection layer laminated on the copper-containing layer, the method comprising step (1) of contacting the copper-containing layer of a first semiconductor having a copper-containing layer with the copper surface protection composition according to any one of [1] to [7] above to form the copper surface protection layer. [9] The method for producing the first semiconductor intermediate according to [8] above, which comprises, before step (1), a step of cleaning the copper-containing layer with a cleaning liquid.

[10] The method for producing the first semiconductor intermediate according to [9] above, wherein the cleaning liquid contains at least one selected from the group consisting of hydrofluoric acid, sulfuric acid, nitric acid, and ammonia.

[11] A method for producing a semiconductor including a copper-containing bonding layer, the method comprising: removing a copper surface protective layer from a first semiconductor intermediate produced by the method according to any one of [8] to

[10] above to expose a copper-containing layer; and bonding the exposed copper-containing layer to a metal-containing layer in a second semiconductor intermediate, the second semiconductor intermediate including a metal-containing layer, to form a copper-containing bonding layer.

[0010] The present invention provides a copper surface protection composition that can prevent oxidation of copper surfaces, which can prevent oxidation of the copper surface of, for example, a semiconductor, allowing for the production of semiconductors with favorable interconnections formed in 3D integration technology.

[0011] Hereinafter, embodiments of the present invention will be described in detail.

[0012] <Copper surface protection composition> The copper surface protection composition contains at least one copper surface protective agent selected from the group consisting of compounds represented by formulas (1) to (3) and salts thereof, and a solvent. The copper surface protection composition may further contain a pH adjuster, a surfactant, a viscosity adjuster, a chelating agent, a reducing agent, an antifoaming agent, etc. The copper surface protection composition is preferably used in the production of semiconductors.

[0013] The copper surface protection composition according to the present invention can prevent oxidation of the copper surface. Specifically, a copper surface protection layer can be formed by contacting the copper surface (e.g., a copper-containing layer of a semiconductor) with the copper surface protection composition. The copper surface protection layer is a dense layer, and therefore can prevent oxygen from permeating. As a result, contact between the copper surface and oxygen can be prevented, and oxidation of the copper surface can be prevented.

[0014] In 3D integration technology, semiconductor intermediates each having two interconnected copper-containing layers are individually manufactured and then stacked to produce a semiconductor, which may result in a long storage period for the semiconductor intermediate having the copper-containing layer. According to the surface protection composition of the present invention, the copper surface protection layer formed on the copper-containing layer can be stably maintained for a long period, allowing the semiconductor intermediate having the copper surface protection layer to be stored for a long period.

[0015] In one embodiment, the copper surface protection composition has excellent usability because the copper surface protection layer formed is highly removable. Because a covalent bond between the copper and the copper surface protection layer is not necessarily required, the copper surface protection layer can be easily removed by, for example, heating, hydrogen ashing, or ion irradiation with an inert gas. Therefore, the copper surface protection composition has excellent usability.

[0016] [Copper Surface Protective Agent] The copper surface protective agent is selected from the group consisting of compounds represented by formulas (1) to (3) and salts thereof.

[0017]

[0018] In the above formulas (1) to (3), R is a substituted or unsubstituted alkyl group having 3 to 30 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms.

[0019] The alkyl group having 3 to 30 carbon atoms is not particularly limited, and examples thereof include a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, an octadecyl group, and an icosyl group.

[0020] When the alkyl group having 3 to 30 carbon atoms has a substituent, the substituent is not particularly limited, and examples thereof include an alkoxy group having 1 to 30 carbon atoms such as a methoxy, ethoxy, or propyloxy group; a hydroxy group; a cyano group; a nitro group; a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom); etc. The alkyl group may have one substituent or a combination of two or more substituents.

[0021] Examples of the aryl group having 6 to 30 carbon atoms include a phenyl group, a naphthyl group, and an anthracenyl group.

[0022] When the aryl group having 6 to 30 carbon atoms has a substituent, the substituent is not particularly limited, and examples thereof include alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, propyl, isopropyl, and butyl; alkoxy groups having 1 to 30 carbon atoms such as methoxy, ethoxy, and propyloxy; hydroxy groups; cyano groups; nitro groups; halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms); etc. The aryl group may have one substituent or a combination of two or more substituents.

[0023] Furthermore, "salts thereof" refer to compounds having a structure in which at least one of the hydroxyl groups of formulas (1) to (3) is a salt with a hydroxide ion. Specific examples include compounds represented by the following formulas (1-1) to (3-1).

[0024]

[0025] In the above formulas (1-1) to (3-1), R is the same as in formulas (1) to (3). ＋ are each independently a monovalent cation. In this case, two X ＋ , two X in the compounds of formula (1-2) and (2-2) ＋ may be one divalent cation. For example, two compounds of formula (1-1) may have the following structure containing a divalent cation:

[0026]

[0027] The monovalent cation is not particularly limited, and examples thereof include sodium cation, potassium cation, ammonium cation, quaternary ammonium cation (methylammonium cation, ethylammonium cation, dimethylammonium cation, trimethylammonium cation, tetramethylammonium cation), etc. These monovalent cations may be contained alone or in combination of two or more.

[0028] The divalent cation is not particularly limited, but examples thereof include magnesium cation, calcium cation, strontium cation, and barium cation.

[0029] Specific examples of copper surface protective agents include, but are not limited to, compounds represented by formula (1) such as propylphosphonic acid, butylphosphonic acid, pentylphosphonic acid, hexylphosphonic acid, heptylphosphonic acid, octylphosphonic acid, nonylphosphonic acid, decylphosphonic acid, undecylphosphonic acid, dodecylphosphonic acid, phenylphosphonic acid, 4-methylphenylphosphonic acid, and naphthylphosphonic acid; propylphosphonic acid, butylphosphonic acid, pentylphosphonic acid, hexylphosphonic acid, heptylphosphonic acid, octylphosphonic acid, nonylphosphonic acid, decylphosphonic acid, and undecylphosphonic acid; compounds represented by formula (2), such as propylbenzenesulfonic acid, butylbenzenesulfonic acid, pentylbenzenesulfonic acid, hexylbenzenesulfonic acid, heptylbenzenesulfonic acid, octylbenzenesulfonic acid, nonylbenzenesulfonic acid, decylbenzenesulfonic acid, undecylbenzenesulfonic acid, dodecylbenzenesulfonic acid, phenylbenzenesulfonic acid, and 4-dodecylbenzenesulfonic acid; and salts thereof. Among these, the copper surface protective agent preferably contains at least one of the compounds represented by formula (1) and salts thereof, more preferably at least one selected from the group consisting of propylphosphonic acid, butylphosphonic acid, pentylphosphonic acid, hexylphosphonic acid, heptylphosphonic acid, octylphosphonic acid, nonylphosphonic acid, decylphosphonic acid, undecylphosphonic acid, dodecylphosphonic acid, and salts thereof, even more preferably at least one selected from the group consisting of heptylphosphonic acid, octylphosphonic acid, nonylphosphonic acid, and salts thereof, and particularly preferably octylphosphonic acid and / or a salt thereof. The copper surface protective agents may be used alone or in combination of two or more.

[0030] The content of the copper surface protective agent is preferably 0.00001 to 1 mass %, more preferably 0.0001 to 1 mass %, even more preferably 0.001 to 0.5 mass %, and particularly preferably 0.005 to 0.1 mass %, relative to the total mass of the copper surface protective composition. A copper surface protective agent content of 0.00001 mass % or more is preferred because a dense copper surface protective layer can be formed. On the other hand, a copper surface protective agent content of 1 mass % or less is preferred because it is easy to prepare a uniform composition.

[0031] [Solvent] The solvent is not particularly limited, but examples thereof include water and organic solvents.

[0032] The water is not particularly limited, but is preferably water from which metal ions, organic impurities, particle particles, etc. have been removed by distillation, ion exchange treatment, filtration, various adsorption treatments, etc., more preferably pure water, and particularly preferably ultrapure water.

[0033] The organic solvent is not particularly limited, and examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and tert-butanol; polyhydric alcohols such as ethylene glycol, propylene glycol, neopentyl glycol, 1,2-hexanediol, 1,6-hexanediol, 2-ethylhexane-1,3-diol, and glycerin; and glycol ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monoethyl ether, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether, tripropylene glycol n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, and propylene glycol phenyl ether.

[0034] Of the above, the solvent is preferably water. The solvents may be used alone or in combination of two or more.

[0035] The addition rate of the solvent, particularly water, is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, relative to the total mass of the copper surface protection composition.

[0036] [pH Adjuster] The pH adjuster has the function of adjusting the pH of the copper surface protection composition.

[0037] pH adjusters include acidic and basic compounds.

[0038] The acidic compound is not particularly limited, and examples thereof include inorganic strong acid compounds such as hydrogen chloride, hydrogen bromide, hydrogen iodide, sulfuric acid, and nitric acid; organic strong acid compounds such as methanesulfonic acid and benzenesulfonic acid; inorganic weak acid compounds such as phosphoric acid; and organic weak acid compounds such as acetic acid and citric acid.

[0039] The basic compound is not particularly limited, and examples thereof include strong inorganic basic compounds such as sodium hydroxide, potassium hydroxide, calcium hydroxide, and barium hydroxide; strong organic basic compounds such as tetramethylammonium hydroxide (TMAH) and tetraethylammonium hydroxide (TEAH); weak inorganic basic compounds such as sodium carbonate and ammonia; and weak organic basic compounds such as diazabicycloundecene (DBU) and diazabicyclononene (DBU).

[0040] Of these, the pH adjuster preferably contains at least one selected from the group consisting of inorganic strong acid compounds, inorganic strong base compounds, and inorganic weak base compounds, more preferably contains at least one selected from the group consisting of sulfuric acid, nitric acid, sodium hydroxide, potassium hydroxide, calcium hydroxide, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), and ammonia, even more preferably contains at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), and ammonia, and particularly preferably contains at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, and calcium hydroxide. The above-mentioned pH adjusters may be used alone or in combination of two or more.

[0041] The content of the pH adjuster is not particularly limited, and is preferably an amount that allows the copper surface protection composition to have a desired pH.

[0042] [Physical Properties of the Copper Surface Protection Composition] The pH of the copper surface protection composition is preferably 0.1 to 13, more preferably 1 to 12.5, even more preferably 2 to 12, and particularly preferably 2.5 to 5.5. By adjusting the pH of the copper surface protection composition, a suitable copper surface protection layer can be formed on the copper surface. While the reason for this effect is not entirely clear, one possible explanation is the change in the surface potential (ζ potential) of copper depending on the pH. Specifically, when the copper surface protection composition has an acidic pH (less than 7.0), the copper surface tends to have a large positive charge, while when the copper surface is basic (more than 7.0), the copper surface tends to have a large negative charge. It is believed that this change in the surface potential (ζ potential) of copper allows the copper surface protective agent contained in the copper surface protection composition to interact favorably with the copper surface.

[0043] <Method for manufacturing a semiconductor intermediate> According to one aspect of the present invention, a method for manufacturing a semiconductor intermediate is provided. In this case, the semiconductor intermediate (first semiconductor intermediate) includes a copper-containing layer and a copper surface protection layer laminated on the copper-containing layer. The method for manufacturing the semiconductor intermediate includes step (1) of contacting the copper-containing layer in the first semiconductor having a copper-containing layer with the copper surface protection composition to form a copper surface protection layer. Furthermore, the semiconductor intermediate may include a step (cleaning step) of cleaning the copper-containing layer with a cleaning solution before step (1). Hereinafter, the cleaning step and step (1) will be described in that order. Note that, in this specification, the term "copper-containing layer" means a layer in which at least metallic copper is present on the layer surface, and the copper-containing layer is preferably a layer made of copper.

[0044] [Cleaning Step] The cleaning step is carried out before step (1), and is a step of cleaning the copper-containing layer of the first semiconductor having the copper-containing layer with a cleaning solution.

[0045] (First Semiconductor) The first semiconductor includes a copper-containing layer. The first semiconductor is not particularly limited, but may be a semiconductor chip or a semiconductor wafer.

[0046] (Cleaning Liquid) The cleaning liquid has a function of cleaning the surface of the copper-containing layer, for example, a function of removing copper oxide formed on the exposed surface of the copper-containing layer.

[0047] The cleaning solution includes a cleaning agent and a solvent.

[0048] The cleaning agent is not particularly limited, but includes at least one selected from the group consisting of an acid and an alkali.

[0049] The acid is not particularly limited, and examples thereof include inorganic acids such as hydrofluoric acid, hydrogen chloride, hydrogen bromide, hydrogen iodide, sulfuric acid, nitric acid, and phosphoric acid; and organic acids such as acetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and 10-camphorsulfonic acid.

[0050] The alkali is not particularly limited, but examples thereof include ammonia and ammonium salts.

[0051] The ammonium salt is not particularly limited, but may be ammonium fluoride (NH ４ F); ammonium hydrogen fluoride (NH ４ F·HF); tetraalkylammonium hydroxides such as tetraethylammonium hydroxide (TEAH), tetramethylammonium hydroxide (TMAH), ethyltrimethylammonium hydroxide, diethyldimethylammonium hydroxide, triethylmethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide; aryl group-containing ammonium hydroxides such as benzyltrimethylammonium hydroxide and benzyltriethylammonium hydroxide; and hydroxy group-containing ammonium hydroxides such as trimethyl(2-hydroxyethyl)ammonium hydroxide, triethyl(2-hydroxyethyl)ammonium hydroxide, tripropyl(2-hydroxyethyl)ammonium hydroxide, and trimethyl(1-hydroxypropyl)ammonium hydroxide.

[0052] Of these, the cleaning agent preferably contains at least one selected from the group consisting of acid and ammonia, more preferably at least one selected from the group consisting of hydrofluoric acid, hydrogen chloride, hydrogen bromide, hydrogen iodide, sulfuric acid, nitric acid, and ammonia, even more preferably at least one selected from the group consisting of hydrofluoric acid, sulfuric acid, nitric acid, and ammonia, particularly preferably at least one selected from the group consisting of sulfuric acid, nitric acid, and ammonia, and most preferably sulfuric acid. Note that the cleaning agents may be used alone or in combination of two or more.

[0053] The content of the detergent is preferably 0.001 to 50 mass %, more preferably 0.01 to 10 mass %, further preferably 0.03 to 3 mass %, and particularly preferably 0.05 to 2 mass %, relative to the total mass of the cleaning liquid.

[0054] The solvent is not particularly limited, but examples thereof include the same solvents as those used in the copper surface protection composition. Among these, the solvent is preferably water. The solvents may be used alone or in combination of two or more.

[0055] The content of the solvent, particularly water, relative to the total mass of the cleaning solution is preferably 50% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0056] The cleaning solution may further contain a pH adjuster. The pH adjuster is not particularly limited, but examples thereof include the same pH adjusters as those used in the copper surface protection composition. These pH adjusters may be used alone or in combination of two or more.

[0057] The pH of the cleaning solution is not particularly limited, but is preferably 0.1 to 13, more preferably 0.5 to 10, even more preferably 0.5 to 5, and particularly preferably 0.4 to 2.5.

[0058] (Cleaning) The cleaning method is not particularly limited, and known techniques can be appropriately adopted. Specifically, the first semiconductor may be immersed in a cleaning solution, or the cleaning solution may be sprayed or dropped (single wafer spin treatment, etc.) onto the copper-containing layer surface of the first semiconductor. In this case, the immersion may be repeated two or more times, the spraying may be repeated two or more times, or the dropping may be repeated two or more times, or immersion, spraying, and dropping may be combined.

[0059] The washing temperature is not particularly limited, but is preferably 0 to 90°C, more preferably 5 to 70°C, and even more preferably 10 to 50°C.

[0060] The cleaning time is not particularly limited, but is preferably from 10 seconds to 3 hours, more preferably from 10 seconds to 1 hour, even more preferably from 15 seconds to 45 minutes, and particularly preferably from 30 seconds to 20 minutes.

[0061] [Step (1)] Step (1) is a step of forming a copper surface protection layer by contacting the copper surface protection composition described above with the copper-containing layer of a first semiconductor having the copper-containing layer.

[0062] (First Semiconductor) The first semiconductor is the one described above. In this case, the first semiconductor is preferably subjected to the above-mentioned cleaning step to remove copper oxide that may be contained in the copper-containing layer.

[0063] (Copper Surface Protection Composition) The copper surface protection composition used is the one described above.

[0064] (Contact) The contact method is not particularly limited, and known techniques can be appropriately adopted. Specifically, the first semiconductor may be immersed in the copper surface protection composition, or the copper surface protection composition may be sprayed or dripped (e.g., single-wafer spin treatment) onto the surface of the copper-containing layer of the first semiconductor. In this case, the immersion may be repeated two or more times, the spraying may be repeated two or more times, or the dripping may be repeated two or more times, or immersion, spraying, and dripping may be combined.

[0065] The contact temperature is not particularly limited, but is preferably 0 to 90°C, more preferably 5 to 70°C, and even more preferably 10 to 65°C.

[0066] The contact time is not particularly limited, but is preferably from 10 seconds to 3 hours, more preferably from 10 seconds to 1 hour, even more preferably from 1 to 45 minutes, and particularly preferably from 3 to 20 minutes.

[0067] After contact, excess copper surface protection composition, etc., can be washed away with water, isopropyl alcohol, etc. as appropriate to remove the solvent contained in the copper surface protection composition adhering to the surface of the copper-containing layer, thereby forming a copper surface protection layer.

[0068] [Copper Surface Protective Layer] The copper surface protective layer contains a copper surface protective agent. Since the copper surface protective layer is a dense layer, oxygen is less likely to permeate through it. As a result, contact of oxygen with the copper-containing layer can be prevented, and oxidation of the surface of the copper-containing layer can be prevented.

[0069] The thickness of the copper surface protective layer is not particularly limited, but is preferably 0.1 to 50 nm, more preferably 0.2 to 10 nm, even more preferably 0.3 to 2 nm, and particularly preferably 0.4 to 1 nm. In this specification, the thickness of the "copper surface protective layer" refers to the maximum thickness of the copper surface protective layer in the perpendicular direction to the contact surface between the copper-containing layer and the copper surface protective layer.

[0070] [First Semiconductor Intermediate Body] The first semiconductor intermediate body includes a copper-containing layer and a copper surface protection layer laminated on the copper-containing layer. Note that, depending on the structure of the first semiconductor, the copper surface protection layer may cover not only the copper-containing layer but also part or all of other layers such as an insulating layer and a silicon substrate layer.

[0071] The first semiconductor intermediate has a copper surface protective layer formed on the copper-containing layer, which prevents oxidation of the surface of the copper-containing layer, allowing the first semiconductor intermediate to be stored for a long period of time.

[0072] <Method for manufacturing a semiconductor> According to one aspect of the present invention, a method for manufacturing a semiconductor is provided. In this case, the semiconductor includes a copper-containing bonding layer. The method for manufacturing a semiconductor includes a step of removing the copper surface protective layer of a first semiconductor intermediate manufactured by the above method to expose the copper-containing layer (exposing step), and a step of bonding the exposed copper-containing layer to a metal-containing layer in a second semiconductor intermediate including a metal-containing layer to form a copper-containing bonding layer (bonding step). In this specification, the term "metal-containing layer" means a layer in which at least a metal is present on the surface, and the metal-containing layer is preferably a layer made of a metal. In this case, the "metal" is one that can be bonded to copper, preferably copper or tin, and more preferably copper.

[0073] [Exposing Step] The exposing step is a step of removing the copper surface protective layer of the first semiconductor intermediate body to expose the copper-containing layer.

[0074] (First Semiconductor Intermediate Body) The first semiconductor intermediate body is the one described above.

[0075] (Removal) The method for removing the copper surface protection layer of the first semiconductor intermediate is not particularly limited, but is preferably heating, hydrogen ashing, or inert gas ion irradiation, and more preferably heating. Heating may also be performed in an inert gas atmosphere. Examples of inert gases include nitrogen and argon.

[0076] The heating temperature is not particularly limited, but is preferably 100 to 300°C, and more preferably 150 to 250°C.

[0077] The heating time is not particularly limited, but is preferably from 0.1 seconds to 3 hours, more preferably from 1 second to 1 hour, even more preferably from 10 seconds to 15 minutes, and particularly preferably from 1 minute to 15 minutes.

[0078] By removing the copper surface protection layer of the first semiconductor, the copper-containing layer can be exposed, i.e., the first semiconductor having the copper-containing layer can be obtained.

[0079] [Bonding Step] The bonding step is a step of bonding the exposed copper-containing layer to a metal-containing layer in a second semiconductor intermediate body including the metal-containing layer to form a copper-containing bonding layer.

[0080] (Exposed Copper-Containing Layer) The exposed copper-containing layer was covered with the copper surface protective layer and thus had almost no contact with oxygen until the exposing step was performed, and therefore the copper on the exposed copper-containing layer surface was hardly oxidized.

[0081] (Second semiconductor intermediate including a metal-containing layer) The second semiconductor intermediate includes a metal-containing layer. The second semiconductor intermediate is not particularly limited, but examples thereof include a semiconductor chip or a semiconductor wafer. When the metal-containing layer is a copper-containing layer, the second semiconductor intermediate may be manufactured by the same method as the first semiconductor intermediate. In this case, the second semiconductor intermediate is used in the bonding step after the above-mentioned exposure step.

[0082] Bonding Bonding can interconnect copper-containing layers and metal-containing layers to provide three-dimensional (3D) integrated semiconductors.

[0083] The joining method is not particularly limited, but thermocompression bonding is preferred.

[0084] The bonding temperature is not particularly limited, but is preferably 80 to 500°C, more preferably 90 to 300°C, further preferably 100 to 250°C, and particularly preferably 120 to 200°C.

[0085] The bonding time is not particularly limited, but is preferably 0.01 to 600 seconds, and more preferably 0.1 to 60 seconds.

[0086] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0087] Example 1 A copper surface protection composition was prepared by mixing butylphosphonic acid as a copper surface protection agent with water as a solvent, where the content of butylphosphonic acid was 0.01% by mass based on the total mass of the copper surface protection composition.

[0088] The pH of the copper surface protection composition was measured to be 3.2 at 23°C using a tabletop pH meter (F-71) (manufactured by Horiba, Ltd.) and a pH electrode (9615S-10D) (manufactured by Horiba, Ltd.).

[0089] [Example 2] Except for using hexylphosphonic acid as the copper surface protective agent, a copper surface protective composition was produced in the same manner as in Example 1. The pH of the copper surface protective composition was measured in the same manner as in Example 1 and was found to be 3.3.

[0090] [Example 3] Except for using octylphosphonic acid as the copper surface protective agent, a copper surface protective composition was produced in the same manner as in Example 1. The pH of the copper surface protective composition was measured in the same manner as in Example 1 and was found to be 3.4.

[0091] [Example 4] A copper surface protection composition was produced in the same manner as in Example 1, except that dodecyl phosphate was used as the copper surface protective agent so that the content was 0.001 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 4.5.

[0092] [Example 5] Except for using phenylphosphonic acid as the copper surface protective agent, a copper surface protective composition was produced in the same manner as in Example 1. The pH of the copper surface protective composition was measured in the same manner as in Example 1 and was found to be 3.2.

[0093] Example 6 A copper surface protection composition was produced in the same manner as in Example 1, except that 4-dodecylbenzenesulfonic acid was used as the copper surface protective agent so that the content was 0.05 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 2.9.

[0094] [Example 7] A copper surface protection composition was produced in the same manner as in Example 3, except that sulfuric acid was further added as a pH adjuster so that the content was 1 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 1.2.

[0095] [Example 8] A copper surface protection composition was produced in the same manner as in Example 3, except that sulfuric acid was further added as a pH adjuster so that the content was 0.05 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 2.1.

[0096] [Example 9] A copper surface protection composition was produced in the same manner as in Example 3, except that ammonia was further added as a pH adjuster so that the content was 0.0006 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 4.0.

[0097] [Example 10] A copper surface protection composition was produced in the same manner as in Example 3, except that ammonia was further added as a pH adjuster so that the content was 0.0007 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 5.0.

[0098] [Example 11] A copper surface protection composition was produced in the same manner as in Example 3, except that ammonia was further added as a pH adjuster so that the content was 0.0012 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 6.0.

[0099] [Example 12] A copper surface protection composition was produced in the same manner as in Example 3, except that ammonia was further added as a pH adjuster so that the content was 0.0014 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 7.0.

[0100] [Example 13] A copper surface protection composition was produced in the same manner as in Example 3, except that ammonia was further added as a pH adjuster so that the content was 0.0016 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 8.0.

[0101] [Example 14] A copper surface protection composition was produced in the same manner as in Example 3, except that ammonia was further added as a pH adjuster so that the content was 0.0031 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 9.0.

[0102] [Example 15] A copper surface protection composition was produced in the same manner as in Example 3, except that ammonia was further added as a pH adjuster so that the content was 0.013 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 10.0.

[0103] [Example 16] A copper surface protection composition was produced in the same manner as in Example 3, except that tetramethylammonium hydroxide (TMAH) was further added as a pH adjuster so that the content was 0.018 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 11.0.

[0104] [Example 17] A copper surface protection composition was produced in the same manner as in Example 3, except that tetramethylammonium hydroxide (TMAH) was further added as a pH adjuster so that the content was 0.075 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 12.0.

[0105] [Example 18] A copper surface protection composition was produced in the same manner as in Example 3, except that sodium hydroxide (NaOH) was further added as a pH adjuster to a content of 0.0026 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 5.0.

[0106] [Example 19] A copper surface protection composition was produced in the same manner as in Example 3, except that potassium hydroxide (KOH) was further added as a pH adjuster to a content of 0.0029 mass %. The pH of the copper surface protection composition was measured in the same manner as in Example 1 and was found to be 5.0.

[0107] Comparative Example 1 A composition was produced in the same manner as in Example 1, except that benzotriazole was used in a content of 0.05 mass % instead of the copper surface protective agent. The pH of the composition was measured in the same manner as in Example 1 and was found to be 5.2.

[0108] Comparative Example 2 A composition was produced in the same manner as in Example 1, except that dodecylpyridinium chloride was used in place of the copper surface protective agent so that the content was 0.05 mass %. The pH of the composition was measured in the same manner as in Example 1 and was found to be 4.7.

[0109] Comparative Example 3 A composition was produced in the same manner as in Example 1, except that 1-hydroxyethane-1,1-diphosphonic acid was used in place of the copper surface protective agent so that the content was 0.5 mass %. The pH of the composition was measured in the same manner as in Example 1 and was found to be 1.7.

[0110] Comparative Example 4 A composition was produced in the same manner as in Example 1, except that poly(ammonium 4-styrenesulfonate) (weight average molecular weight Mw = 200,000) was used in a content of 0.05 mass% instead of the copper surface protective agent. The pH of the composition was measured in the same manner as in Example 1 and was found to be 4.8.

[0111] The copper surface protection compositions and the like produced in Examples 1 to 19 and Comparative Examples 1 to 4 are shown in Table 1 below.

[0112]

[0113] The structural formulae of the copper surface protective agents used in the examples and comparative examples are shown below.

[0114]

[0115] [Evaluation] Various evaluations were carried out on the copper surface protection compositions and the like produced in Examples 1 to 19 and Comparative Examples 1 to 4.

[0116] (Copper oxidation rate) (1) Preparation of plated Cu sample SiO ２ A plated Cu sample was prepared by successively depositing a TaN (thickness: 1000 Å), a TaN (thickness: 50 Å), a Ta (thickness: 100 Å), a seed Cu (thickness: 600 Å), and a plated Cu (thickness: 6000 Å).

[0117] (2) Pretreatment 1 cm x 1 cm (immersion treatment area: 1 cm ２ The plated Cu sample was immersed in 10 mL of 1% hydrofluoric acid (DHF) at 23°C for 1 minute to remove copper oxide (CuO) from the surface of the plated Cu sample. The sample was then rinsed with water at 23°C for 10 seconds, and nitrogen was blown through to remove water from the surface.

[0118] (3) Formation of Copper Surface Protective Layer The plated Cu sample after copper oxide removal was immersed in a copper surface protective composition or the like for 10 minutes at 20° C. Then, the sample was rinsed with water at 23° C. for 10 seconds, and nitrogen was blown to remove water from the surface, thereby forming a copper surface protective layer on the plated Cu sample.

[0119] (4) Evaluation of Copper Oxidation Rate Plated Cu samples having a copper surface protective layer formed thereon were stored in the air at 20° C. for 24 hours or 120 hours.

[0120] The copper oxidation rate of the plated Cu sample having the copper surface protective layer after storage was measured. Specifically, the plated Cu sample having the copper surface protective layer after storage was analyzed by X-ray photoelectron spectroscopy (XPS; PHI Quantera II manufactured by ULVAC-PHI, Inc.) to obtain a narrow scan spectrum of Cu2p. The obtained narrow scan spectrum of Cu2p was analyzed by curve fitting to obtain the Cu ２＋ Single peak area and Cu ＋ The sum of the peak areas of Cu and Cu was calculated. The copper oxidation rate (Cu ２＋ The peak area of ​​Cu ＋ The higher the copper oxidation rate, i.e., the higher the Cu ＋ and Cu compared to Cu ２＋ The higher the value, the more the plated Cu layer surface of the Cu sample was oxidized during the storage period of the plated Cu sample. The results are shown in Table 2 below. Table 2 also shows the results of a reference example in which "(3) Formation of a copper surface protective layer" was not performed (no copper surface protective composition, etc. was used).

[0121] (Removability of Copper Surface Protective Layer) (1) Preparation and Pretreatment of Cu Samples Pretreated plated Cu samples were prepared in the same manner as in the evaluation of the copper oxidation rate described above.

[0122] (2) Formation of Copper Surface Protective Layer The plated Cu sample after copper oxide removal was immersed in a copper surface protective composition or the like at 20°C for 10 minutes. The sample was then rinsed with water at 23°C for 10 seconds, and nitrogen was blown to remove water from the surface, yielding a plated Cu sample on which a copper surface protective layer had been formed. The water contact angle of the surface of the plated Cu sample on which the copper surface protective layer had been formed was measured and found to be 60° or greater. Because the copper surface protective layer is an organic layer, the water contact angle tends to be larger than that of a copper surface with a high surface free energy.

[0123] (3) Evaluation of Removability of Copper Surface Protective Layer The Cu sample on which the copper surface protective layer was formed was left standing on a hot plate heated to 200° C. for 5 minutes to remove the copper surface protective layer.

[0124] The contact angle of water on the surface of the Cu sample was measured before and after placing it on the hot plate, and evaluated according to the following criteria. Note that when the copper surface protective layer is removed by heating, the copper surface, which has high surface free energy, is exposed, and the contact angle tends to decrease. The results are shown in Table 2 below.

[0125] ○: Water contact angle is less than 25 degrees ×: Water contact angle is 25 degrees or more

[0126]

[0127] The results in Table 2 show that the copper surface protecting compositions of Examples 1 to 19 were able to effectively prevent oxidation of the copper surface by protecting the copper surface.

[0128] [Effect of Pretreatment Agent] The effect of the pretreatment agent on the copper surface before forming a copper surface protective layer using the copper surface protective composition was evaluated.

[0129] (1) 1% Hydrofluoric Acid (DHF) The copper oxidation rate and removability were evaluated in the same manner as above using the copper surface protection composition of Example 3. This example uses 1% hydrofluoric acid (DHF) as the pretreatment agent.

[0130] (2) 1% Sulfuric Acid The copper oxidation rate and removal ability were evaluated in the same manner as in (1) above, except that 1% sulfuric acid was used as the pretreatment agent.

[0131] (3) 0.1% Ammonia The copper oxidation rate and removal ability were evaluated in the same manner as in (1) above, except that 0.1% ammonia was used as the pretreatment agent.

[0132] The results obtained in (1) to (3) above are shown in Table 3 below.

[0133]

[0134] The results in Table 3 show that, regardless of which pretreatment agent was used, the copper surface was protected and oxidation of the copper surface was effectively prevented.

Claims

1. The following formulas (1) to (3): 【Chemistry 1】 [In formulas (1) to (3), R is a substituted or unsubstituted alkyl group having 3 to 30 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. and at least one copper surface protective agent selected from the group consisting of compounds represented by the formula: a solvent; A composition for protecting copper surfaces, comprising:

2. The copper surface protection composition according to claim 1 , wherein the copper surface protective agent comprises a compound represented by formula (1) and / or a salt thereof:

3. 2. The copper surface protecting composition according to claim 1, wherein R is a substituted or unsubstituted alkyl group having 3 to 30 carbon atoms.

4. The copper surface protection composition of claim 1 , further comprising a pH adjuster.

5. 5. The copper surface protection composition according to claim 4, wherein the pH adjuster comprises at least one selected from the group consisting of sodium hydroxide and potassium hydroxide.

6. 2. The copper surface protection composition according to claim 1, wherein the pH is 2.5 to 5.

5.

7. The copper surface protection composition according to claim 1, which is used in the manufacture of semiconductors.

8. A method for producing a first semiconductor intermediate product including a copper-containing layer and a copper surface protection layer laminated on the copper-containing layer, the method comprising: A method for producing a first semiconductor intermediate, comprising: a step (1) of contacting a copper surface protection composition according to any one of claims 1 to 7 with a copper-containing layer in a first semiconductor having the copper-containing layer to form a copper surface protection layer.

9. The method for producing a first semiconductor intermediate according to claim 8 , further comprising, before the step (1), a step of cleaning the copper-containing layer with a cleaning solution.

10. 10. The method for producing a first semiconductor intermediate according to claim 9, wherein the cleaning solution contains at least one selected from the group consisting of hydrofluoric acid, sulfuric acid, nitric acid, and ammonia.

11. 1. A method for manufacturing a semiconductor device comprising a copper-containing bonding layer, comprising: removing the copper surface protective layer of the first semiconductor intermediate produced by the method of claim 8 to expose the copper-containing layer; and bonding the exposed copper-containing layer to a metal-containing layer in a second semiconductor intermediate body including a metal-containing layer to form a copper-containing bonding layer.

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