Cleaning agent, cleaning method, and replenishment liquid

Abstract

The purpose of the present invention is to provide a detergent which is capable of suppressing etching of copper and removing organic substances or copper oxides adhering to the surface of copper wiring. The cleaning agent comprises water-soluble carboxylic acid and hydrogen peroxide, the concentration of the hydrogen peroxide is less than 0.75 wt%, and the pH value of the cleaning agent is less than 2.5. Copper oxide can be removed from the surface of the copper wiring by the water-soluble carboxylic acid. Organic matter adhering to the surface of the copper wiring can be removed by the hydrogen peroxide. The reason for this is that hydrogen peroxide reacts with a water-soluble carboxylic acid in the cleaning agent, thereby generating a peroxycarboxylic acid. Etching of copper wiring can also be suppressed. The reason is that the water-soluble carboxylic acid is adsorbed on the copper surface. In addition, etching can be further suppressed due to less than 0.75 wt%. And the pH value does not reach 2.5, so that the copper oxide can be further removed.

Description

Technical Field

[0001] The invention relates to a cleaning agent, a cleaning method and a replenishing liquid. Background Art

[0002] In the manufacturing process of printed wiring boards, organic substances such as resin scum or fingerprint-like oil may sometimes adhere to and remain on the surface of copper wiring. When manufacturing printed wiring boards by the semi-additive method (i.e., the etching solution used to etch the seed layer between unnecessary conductors) contains nitrogen-containing heterocyclic compounds (see, for example, Patent Documents 1 to 3), but the nitrogen-containing heterocyclic compounds contained in the etching solution may sometimes remain on the surface of copper wiring. On the other hand, a film of copper oxide may sometimes be formed on the surface of copper wiring, for example, due to baking.

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2006-9122

[0006] [Patent Document 2] Japanese Patent No. 5576525

[0007] [Patent Document 3] Japanese Patent Application Publication No. 2015-120970

[0008] [Patent document 4] Japanese Patent No. 6779557. Summary of the invention

[0009] [Problems to be Solved by the Invention]

[0010] If such organic matter or copper oxide remains on the surface of the copper wiring, there is a concern that the adhesion will not be effectively improved if a film (hereinafter sometimes referred to as "adhesion-enhancing film", for example, see Patent Document 4) for improving the adhesion (which may also be referred to as adhesion) between the copper wiring and the resin member is formed on the surface of the copper wiring. On the other hand, if such organic matter or copper oxide remains on the surface of the copper wiring, there is a concern that the surface roughening of the copper wiring cannot be effectively achieved by using a micro-etching solution (i.e., an etching solution for roughening the surface of the copper wiring).

[0011] As a method for cleaning the copper surface, a method of removing the oil adhering to the copper surface with an alkaline cleaner and then removing the copper oxide with an acid micro-etching solution is conceivable.

[0012] However, the micro-etching liquid not only dissolves the copper oxide, but also actively dissolves the copper itself (for example, the copper that was once covered by the film of the copper oxide), so the cleaning using the micro-etching liquid may not be able to cope with the miniaturization of copper wiring that will continue to develop in the future. In other words, considering the development of miniaturization in the future, it may be difficult to use the micro-etching liquid for cleaning purposes.

[0013] Furthermore, the above-mentioned cleaning method (ie, cleaning with an alkaline cleaning agent and then cleaning with an acid micro-etching solution) removes the oil and the copper oxide separately, which is laborious.

[0014] An object of the present invention is to provide a cleaning agent that can suppress copper etching and remove organic matter (hereinafter sometimes referred to as "organic residue") or copper oxide attached to the surface of copper wiring.

[0015] [Technical means to solve the problem]

[0016] In order to solve the problem, the present invention has the following configuration [1]. [1]

[0018] A cleaning agent for a substrate including copper wiring, comprising a water-soluble carboxylic acid, and

[0019] Hydrogen peroxide,

[0020] The concentration of the hydrogen peroxide is less than 0.75% by weight, and

[0021] The pH value of the above detergents is less than 2.5.

[0022] Here, the "cleaning agent for a substrate including copper wiring" means an aqueous solution for cleaning a substrate including copper wiring.

[0023] The "copper" in the "copper wiring" may be copper itself or a copper alloy. That is, the "copper wiring" may be a wiring composed of copper or a wiring composed of a copper alloy.

[0024] The present invention preferably further comprises the following configurations [2] and later. [2]

[0026] The cleaning agent described in [1] does not substantially contain a nitrogen-containing heterocyclic compound. [3]

[0028] The cleaning agent as described in [1] does not contain a nitrogen-containing heterocyclic compound. [4]

[0030] A cleaning agent as described in any one of [1] to [3], wherein the water-soluble carboxylic acid is at least one carboxylic acid selected from the group consisting of formic acid, acetic acid, propionic acid, glycolic acid, oxalic acid, malonic acid, succinic acid, maleic acid, lactic acid, malic acid, citric acid, glycine, α-alanine and β-alanine. [5]

[0032] The cleaning agent as described in any one of [1] to [4], wherein the concentration of the water-soluble carboxylic acid is 0.2% by weight or more. [6]

[0034] The cleaning agent as described in any one of [1] to [5], wherein the concentration of the hydrogen peroxide is 0.05% by weight or more. [7]

[0036] The cleaning agent as described in any one of [1] to [6], wherein the chloride ion concentration is 0.05 ppm or more. [8]

[0038] The cleaning agent as described in any one of [1] to [7] is used for cleaning the substrate before forming a film for improving the adhesion between the copper wiring and the resin member on the surface of the copper wiring. [9]

[0040] A cleaning method comprising the step of cleaning a substrate including copper wiring using the cleaning agent described in any one of [1] to [8].

[10]

[0042] A replenishing liquid which is added to the cleaning agent described in any one of [1] to [8] when the cleaning agent is used continuously or repeatedly.

[0043] The replenishing solution comprises a water-soluble carboxylic acid, and

[0044] Hydrogen peroxide, and

[0045] The pH value did not reach 2.5. DETAILED DESCRIPTION

[0046] <1. First>

[0047] The cleaning agent of the present embodiment (i.e., the cleaning agent for a substrate including copper wiring) contains a water-soluble carboxylic acid, and

[0048] Hydrogen peroxide,

[0049] The concentration of the hydrogen peroxide is less than 0.75% by weight, and

[0050] The pH value of the above detergents is less than 2.5.

[0051] The cleaning agent of this embodiment contains a water-soluble carboxylic acid, and therefore can dissolve the copper oxide on the surface of the copper wiring (that is, the film of the copper oxide on the surface of the copper wiring), and thus can remove the copper oxide from the surface of the copper wiring.

[0052] Furthermore, since the cleaning agent of this embodiment also contains hydrogen peroxide, it is possible to remove organic matter attached to the surface of the copper wiring. This is believed to be because hydrogen peroxide reacts with water-soluble carboxylic acid in the cleaning agent to generate peroxycarboxylic acid, which is a strong oxidant, and the organic matter is decomposed by the peroxycarboxylic acid.

[0053] In addition, the cleaning agent of this embodiment can suppress the dissolution of copper in the copper wiring (for example, copper that was once covered with a film of copper oxide). That is, it can suppress the etching of the copper wiring. It is believed that the reason for this is that although copper can be oxidized by hydrogen peroxide, the water-soluble carboxylic acid is adsorbed on the copper surface, thereby suppressing the oxidation of copper caused by hydrogen peroxide (that is, suppressing the generation of copper oxide).

[0054] Furthermore, since the concentration of hydrogen peroxide is less than 0.75% by weight, the dissolution (ie, etching) of copper by hydrogen peroxide can be further suppressed.

[0055] Furthermore, since the pH value of the cleaning agent of this embodiment is less than 2.5, copper oxides can be further removed.

[0056] Hereinafter, embodiments of the present invention will be described in more detail.

[0057] <2. Cleaning agent>

[0058] The cleaning agent of the present embodiment (i.e., the cleaning agent for cleaning the substrate containing copper wiring) contains a water-soluble carboxylic acid. Since the water-soluble carboxylic acid is contained, the copper oxide on the surface of the copper wiring (i.e., the film of the copper oxide on the surface of the copper wiring) can be dissolved. Therefore, the copper oxide can be removed from the surface of the copper wiring. The water-soluble carboxylic acid can also suppress the dissolution of the copper of the copper wiring (e.g., the copper that was once covered by the film of the copper oxide). That is, the etching of the copper wiring can be suppressed. It is believed that the reason is that although the copper can be oxidized by hydrogen peroxide, the water-soluble carboxylic acid is adsorbed on the copper surface, thereby suppressing the oxidation of the copper caused by the hydrogen peroxide (i.e., suppressing the generation of the copper oxide).

[0059] Examples of the water-soluble carboxylic acid include formic acid, acetic acid, propionic acid, glycolic acid, oxalic acid, malonic acid, succinic acid, maleic acid, lactic acid, malic acid, citric acid, glycine, α-alanine, and β-alanine. Among them, formic acid, acetic acid, propionic acid, succinic acid, maleic acid, lactic acid, malic acid, citric acid, and glycine are preferred, and malic acid and acetic acid are more preferred.

[0060] Regarding the solubility of the water-soluble carboxylic acid, specifically, the solubility of the water-soluble carboxylic acid with respect to 100 g of water at 20° C. is, for example, preferably 0.5 g or more, more preferably 5 g or more, still more preferably 10 g or more, and still more preferably 15 g or more.

[0061] The concentration of the water-soluble carboxylic acid is preferably 0.2% by weight or more, more preferably 0.5% by weight or more, and even more preferably 1.0% by weight or more. If it is 0.5% by weight or more, copper oxide can be further removed from the copper wiring surface, and organic residues attached to the copper wiring surface can be further removed. The concentration of the water-soluble carboxylic acid can be 1.5% by weight or more, and can also be 2.0% by weight or more, and can also be 3.0% by weight or more. On the other hand, the concentration of the water-soluble carboxylic acid can be 40% by weight or less, and can also be 30% by weight or less, and can also be 20% by weight or less, and can also be 15% by weight or less, and can also be 14% by weight or less.

[0062] The cleaning agent of this embodiment further contains hydrogen peroxide. Since the cleaning agent of this embodiment further contains hydrogen peroxide, organic matter attached to the surface of the copper wiring can be removed. This is believed to be because hydrogen peroxide reacts with water-soluble carboxylic acid in the cleaning agent to generate peroxycarboxylic acid as a strong oxidant, and the organic matter is decomposed by the peroxycarboxylic acid.

[0063] The concentration of hydrogen peroxide is preferably 0.05 wt % or more, more preferably 0.07 wt % or more, and even more preferably 0.10 wt % or more. If it is 0.05 wt % or more, organic residues attached to the surface of the copper wiring can be further removed. The concentration of hydrogen peroxide may also be 0.20 wt % or more, or 0.30 wt % or more.

[0064] On the other hand, the concentration of hydrogen peroxide is less than 0.75 wt %. Since the concentration of hydrogen peroxide is less than 0.75 wt %, the dissolution (i.e., etching) of copper caused by hydrogen peroxide can be further suppressed. The concentration of hydrogen peroxide may be less than 0.70 wt %, less than 0.65 wt %, or less than 0.60 wt %.

[0065] The detergent of the present embodiment preferably contains an additive for preventing the decomposition of hydrogen peroxide, i.e., a hydrogen peroxide decomposition inhibitor. As the hydrogen peroxide decomposition inhibitor, for example, cresol sulfonic acid can be cited. The concentration of the hydrogen peroxide decomposition inhibitor is preferably 0.1% by weight or more, more preferably 0.3% by weight or more. On the other hand, the concentration of the hydrogen peroxide decomposition inhibitor is preferably 6% by weight or less, more preferably 4% by weight or less, and even more preferably 2% by weight or less.

[0066] The cleaning agent of the present embodiment may also contain chloride ions. The chloride ion concentration is preferably above 0.05ppm. If the cleaning agent of the present embodiment contains a corresponding amount (e.g., above 0.05ppm) of chloride ions, the effect of chloride ions that may be dissolved from the copper wiring on the performance of the cleaning agent can be reduced. This is explained. The copper plating solution used to form copper wiring sometimes contains chloride ions. If the substrate containing the copper wiring formed by this copper plating solution is cleaned, the chloride ions may be dissolved into the cleaning agent. If the cleaning agent of the present embodiment already contains a corresponding amount (e.g., above 0.05ppm) of chloride ions in advance, the effect of chloride ions dissolved from the copper wiring on the performance of the cleaning agent can be reduced. The chloride ion concentration may be above 0.1ppm, may be above 0.5ppm, or may be above 1ppm. On the other hand, the chloride ion concentration is preferably below 30ppm. The chloride ion concentration may be below 20ppm, may be below 10ppm, or may be below 5ppm. Furthermore, as the ion source of chloride ion, for example, hydrochloric acid, sodium chloride, calcium chloride, potassium chloride, ammonium chloride, etc. can be listed. Among them, sodium chloride is preferred. Furthermore, the ion source can of course be used in the form of an aqueous solution. For example, sodium chloride can be used in the form of a sodium chloride aqueous solution. Furthermore, a chloride ion standard solution (1000 mg / L) for ion chromatography can also be used as a sodium chloride aqueous solution.

[0067] The cleaning agent of this embodiment may or may not contain an inorganic acid. Examples of the inorganic acid include sulfuric acid, nitric acid, fluoroboric acid, phosphoric acid, aminosulfonic acid, and hydrochloric acid. When an inorganic acid is added to adjust the pH value, an inorganic acid other than hydrochloric acid is preferably used among the inorganic acids exemplified herein. The reason for this is that hydrochloric acid has an effect on the chloride ion concentration. Sulfuric acid and nitric acid are particularly preferred.

[0068] The cleaning agent of this embodiment may also contain other components such as surfactants and copper ions. However, the cleaning agent of this embodiment preferably does not contain surfactants. The cleaning agent of this embodiment preferably does not contain copper ions.

[0069] The cleaning agent of this embodiment preferably does not substantially contain nitrogen-containing heterocyclic compounds. The reason for this is that nitrogen-containing heterocyclic compounds are adsorbed on copper wiring, which may result in reduced adhesion between the substrate (i.e., the substrate including the copper wiring) and the resin member (e.g., build-up film). Here, "substantially does not contain nitrogen-containing heterocyclic compounds" means that the concentration of nitrogen-containing heterocyclic compounds is greater than 0% by weight and less than 0.0001% by weight.

[0070] The cleaning agent of this embodiment preferably does not contain a nitrogen-containing heterocyclic compound because it is possible to avoid a decrease in adhesion that may be caused by the nitrogen-containing heterocyclic compound.

[0071] The nitrogen-containing heterocyclic compound is a heterocyclic compound containing a nitrogen atom as an atom constituting the ring. Furthermore, the nitrogen-containing heterocyclic compound may also contain other heteroatoms as atoms constituting the ring. Examples of such heteroatoms include oxygen atoms and sulfur atoms.

[0072] Examples of nitrogen-containing heterocyclic compounds include azoles, pyridines, and morpholines. Examples of azoles include imidazoles, pyrazoles, triazoles, tetrazoles, and derivatives thereof. Specifically, examples include imidazole, 2-methylimidazole, 1,2-diethylimidazole, benzimidazole, pyrazole, triazole, and benzotriazole. In addition, examples include amino-containing azoles such as 2-aminoimidazole, 3-aminopyrazole, 4-aminopyrazole, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole, and 5-aminotetrazolyl. Examples of pyridines include aminopyridines such as 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 2,3-diaminopyridine, 2,6-diaminopyridine, 2,3,6-triaminopyridine, 2,4,6-triaminopyridine, and 4,5,6-triaminopyridine. Examples of the morpholines include N-substituted morpholines such as 4-methylmorpholine, 4-ethylmorpholine, 4-propylmorpholine, 4-isopropylmorpholine, 4-isobutylmorpholine, 4-(2-hydroxyethyl)morpholine, 4-(2-aminoethyl)morpholine, 4-acetylmorpholine, N-(2-cyclohexylcarbonyloxyethyl)morpholine, 3-morpholino-1,2-propanediol, morpholinoacetonitrile, N-(2-cyanoethyl)morpholine, ethyl 3-(morpholino)propionate, 4-(2-aminoethyl)morpholine, N-cyanomethylmorpholine, N-(3-aminopropyl)morpholine, 4-(3-chloropropyl)morpholine, N-(2-hydroxypropyl)morpholine, 4-(3-hydroxypropyl)morpholine, and 1-morpholino-1-cyclohexene.

[0073] The cleaning agent of this embodiment is an aqueous solution, which contains water. As water, it is preferably water from which ionic substances and impurities have been removed, for example, preferably ion exchange water, pure water, ultrapure water, etc. Furthermore, the cleaning agent of this embodiment can be prepared by dissolving the above components in water.

[0074] The pH value of the cleaning agent of this embodiment is less than 2.5. Since the pH value is less than 2.5, copper oxide can be further removed. The pH value may be less than 2.3, less than 2.0, less than 1.8, or less than 1.6. On the other hand, the pH value is preferably greater than 0.2, more preferably greater than 0.4, and more preferably greater than 0.5. The pH value may be greater than 0.7, greater than 0.9, or greater than 1.0.

[0075] In the cleaning agent of the present embodiment, the lower the etching rate of the electroplated copper layer, the better. The etching rate of the electroplated copper layer is preferably 0.19 μm / min or less, more preferably 0.15 μm / min or less, even more preferably 0.12 μm / min or less, even more preferably 0.10 μm / min or less, even more preferably 0.08 μm / min or less, even more preferably 0.06 μm / min or less, even more preferably 0.05 μm / min or less. The etching rate of the electroplated copper layer is a value calculated after measuring the weight change before and after the following cleaning treatment, wherein the cleaning treatment is to shake the electroplated copper substrate for 60 seconds while immersed in a cleaning agent at 30°C. Specifically, the etching rate of the electroplated copper layer is a value measured and calculated by the following examples.

[0076] In the cleaning agent of the present embodiment, the lower the etching rate of the copper sputtering layer, the better. The etching rate of the copper sputtering layer is preferably 170nm / min or less, more preferably 140nm / min or less, even more preferably 120nm / min or less, even more preferably 100nm / min or less, even more preferably 80nm / min or less, even more preferably 70nm / min or less. The etching rate of the copper sputtering layer is a value calculated based on the thickness before and after the following cleaning treatment (specifically, the thickness of the copper sputtering layer), which is a cleaning treatment in which a substrate having a silicon wafer and a copper sputtering layer is immersed in a cleaning agent at 30°C and shaken for 60 seconds. Specifically, the etching rate of the copper sputtering layer is a value measured and calculated by the following examples.

[0077] The cleaning agent of this embodiment can suppress the dissolution of copper in copper wiring (for example, copper that was once covered with a film of copper oxide), so the cleaning agent of this embodiment can be used regardless of how the copper wiring is miniaturized in the future. The cleaning agent of this embodiment can suppress the dissolution of copper in copper wiring, so it may be particularly useful when manufacturing a printed wiring board that requires excellent signal transmission performance (for example, a printed wiring board for high-frequency devices).

[0078] <3. Cleaning method>

[0079] The cleaning agent of this embodiment can be used to clean a substrate containing copper wiring. Among them, it can be well used to clean a substrate containing copper wiring formed by removing a seed layer between unnecessary conductors (i.e., removing non-circuit parts with an etching solution) when manufacturing a printed wiring board by a semi-additive method. That is, it can be well used to clean a substrate containing copper wiring formed by flash etching. Here, the semi-additive method can be a so-called modified semi-additive method (MSAP method).

[0080] The cleaning agent of this embodiment can be particularly well used to clean a substrate after flash etching and before micro etching. That is, it can be well used to clean a substrate before the surface of a copper wiring (specifically, a copper wiring formed by flash etching) is roughened using a micro etching solution. By using the cleaning agent of this embodiment for this purpose (that is, by using it to clean a substrate after flash etching and before micro etching), organic matter and copper oxide can be removed from the surface of the copper wiring, thereby effectively roughening the surface of the copper wiring. As a result, the adhesion between the substrate and the resin component (such as a build-up film) can be improved.

[0081] The cleaning agent of this embodiment can also be well used to clean the substrate after flash etching and before forming a film (i.e., a film that improves adhesion). In other words, it can be well used to clean the substrate before forming a film (i.e., a film that improves adhesion) for improving adhesion between copper wiring and resin components on the surface of the copper wiring. By using the cleaning agent of this embodiment for this purpose (i.e., by cleaning the substrate after flash etching and before forming a film that improves adhesion), organic matter and copper oxide can be removed from the surface of the copper wiring, thereby effectively forming a film that improves adhesion on the surface of the copper wiring. As a result, the adhesion between the substrate and the resin component (e.g., a build-up film) can be improved.

[0082] In addition, "(substrate after) flash etching" is preferably a substrate after the flash etching liquid is removed by water washing or the like and dried as necessary, but may also be a substrate to which the flash etching liquid adheres.

[0083] In order to use the cleaning agent of the present embodiment to clean the substrate containing copper wiring, the cleaning agent of the present embodiment is made to contact at least the copper wiring. In order to make the cleaning agent of the present embodiment contact the copper wiring, for example, the substrate can be immersed in the cleaning agent, and the cleaning agent can also be sprayed on the substrate. In the case of immersing the substrate in the cleaning agent for cleaning, it is preferred to shake the substrate while immersing it in the cleaning agent. Furthermore, the temperature of the cleaning agent is, for example, above 5°C and below 50°C. It can be above 10°C, or above 15°C, or above 20°C. It can be below 45°C, or below 40°C, or below 35°C, or below 30°C. Furthermore, the immersion time (i.e., the time the substrate is immersed in the cleaning agent) can be, for example, more than 3 seconds, preferably more than 10 seconds, and more preferably more than 20 seconds. The immersion time can also be more than 30 seconds, or more than 40 seconds. On the other hand, the immersion time may be less than 600 seconds, or less than 300 seconds. Furthermore, the substrate immersed in the cleaning agent may be rinsed off the cleaning agent (eg, washed with water) as needed, and dried as needed.

[0084] <4. Method for Manufacturing Printed Wiring Board>

[0085] The method for producing a printed wiring board according to the present embodiment includes a step of cleaning a substrate including copper wiring (hereinafter, sometimes referred to as a "cleaning step").

[0086] The manufacturing method of the printed wiring board of the present embodiment may also include the step of bonding the cleaned substrate with a resin component (hereinafter, sometimes referred to as a "bonding step"). The resin component includes a resin. As a resin, for example, thermoplastic resins such as acrylonitrile / styrene copolymer resin (AS resin), acrylonitrile / butadiene / styrene copolymer resin (ABS resin), fluororesin, polyamide, polyethylene, polyethylene terephthalate, polyvinylidene chloride, polyvinyl chloride, polycarbonate, polystyrene, polysulfone, polypropylene, and liquid crystal polymers, or thermosetting resins such as epoxy resins, phenolic resins, polyimides, polyurethanes (ポリウレタン), bismaleimide-triazine resins, modified polyphenylene ethers, and cyanates, or ultraviolet curing epoxy resins, ultraviolet curing acrylic resins, etc. These resins can be modified by functional groups, and can also be strengthened by glass fibers, aromatic polyamide fibers, other fibers, etc. As a specific example of the resin member, there can be cited the build-up film "ABF" manufactured by Ajinomoto Fine-Techno. As the joining method, there can be cited: lamination pressing, lamination, coating, injection molding, transfer molding, etc. If necessary, heating or irradiation with active light can also be performed to harden the resin.

[0087] The method for manufacturing a printed wiring board of the present embodiment may also include a step of forming a film (i.e., a film that improves adhesion) at least on the surface of the copper wiring between the cleaning step and the joining step (hereinafter, sometimes referred to as a "film forming step"). In the film forming step, the film (i.e., the film that improves adhesion) can be formed, for example, in the following order: the film forming composition is brought into contact with at least the surface of the copper wiring, and the solvent contained in the film forming composition is dried and removed as needed. The film forming composition may be an aqueous solution containing a silane coupling agent (e.g., a silane coupling agent having a primary amine group and / or a secondary amine group). As such a film forming composition, for example, the film forming composition described in Patent Document 4 can be cited.

[0088] The method for manufacturing a printed wiring board of the present embodiment may include a step of roughening the surface of the copper wiring of the cleaned substrate using a micro-etching solution between the cleaning step and the bonding step (hereinafter sometimes referred to as a "surface roughening step").

[0089] When the method for producing a printed wiring board of the present embodiment includes both the surface roughening step and the film forming step, it is preferred that the surface roughening step be performed before the film forming step.

[0090] Furthermore, any operation such as washing or drying may be performed before or after each of the above steps as necessary.

[0091] <5. Fluid Supply>

[0092] The replenishing liquid of the present embodiment is a replenishing liquid added to the detergent when the detergent of the present embodiment is used continuously or repeatedly. The replenishing liquid of the present embodiment contains a water-soluble carboxylic acid and hydrogen peroxide, and the pH value does not reach 2.5. The description of the replenishing liquid overlaps with the description of the detergent, so it is omitted. Therefore, the description of the detergent can also be regarded as the description of the replenishing liquid. For the sake of prudence, the description specific to the replenishing liquid is added (however, the description of the detergent should not be denied as the description of the replenishing liquid by the additional description). The concentration of hydrogen peroxide in the replenishing liquid of the present embodiment is preferably higher than the concentration of hydrogen peroxide in the detergent of the present embodiment. Therefore, the concentration of hydrogen peroxide in the replenishing liquid of the present embodiment may be 0.75% by weight or more. For example, the upper limit of the concentration of hydrogen peroxide may be 1.20% by weight, 1.15% by weight, 1.10% by weight, or 1.00% by weight.

[0093] [Example]

[0094] Next, examples of the present invention will be described together with comparative examples. Note that the present invention should not be construed as being limited to the following examples. Note that, hereinafter, "weight %" may be simply described as "%".

[0095] <Preparation of cleaning solution>

[0096] According to Tables 1 to 3, the components shown in these tables are dissolved in ion exchange water to prepare a cleaning solution. The following describes the steps for preparing the cleaning solution by giving several examples.

[0097] For example, in Example 1, malic acid and a 35% aqueous hydrogen peroxide solution were dissolved in ion-exchanged water so as to have 3% by weight of malic acid and 0.53% by weight of hydrogen peroxide, thereby preparing a cleaning solution.

[0098] In Example 3, malic acid, 35% aqueous hydrogen peroxide solution and cresol sulfonic acid were dissolved in ion exchange water to prepare a cleaning solution having a content of 1% by weight of malic acid, 0.11% by weight of hydrogen peroxide and 1% by weight of cresol sulfonic acid.

[0099] In Example 9, malic acid, 35% aqueous hydrogen peroxide solution, cresolsulfonic acid and sodium chloride aqueous solution (specifically, a chloride ion standard solution (1000 mg / L) for ion chromatography) were dissolved in ion exchange water to obtain 3% by weight of malic acid, 0.53% by weight of hydrogen peroxide, 1% by weight of cresolsulfonic acid and a chloride ion concentration of 1 ppm, thereby preparing a cleaning solution.

[0100] In Example 16, malic acid, a 35% aqueous hydrogen peroxide solution, and 62.5% sulfuric acid were dissolved in ion exchange water to prepare a cleaning solution having a malic acid content of 3% by weight, a hydrogen peroxide content of 0.53% by weight, and a pH of 0.6.

[0101] In Comparative Example 1, malic acid was dissolved in ion-exchanged water so as to have a malic acid content of 5% by weight, thereby preparing a cleaning liquid.

[0102] In Comparative Example 2, a cleaning solution was prepared by dissolving a 35% aqueous hydrogen peroxide solution in ion-exchanged water so as to obtain 0.70% by weight of hydrogen peroxide.

[0103] In Comparative Example 3, malic acid, 35% aqueous hydrogen peroxide solution, and 24% aqueous sodium hydroxide solution were dissolved in ion exchange water to prepare a cleaning solution having a malic acid content of 3% by weight, a hydrogen peroxide content of 0.53% by weight, and a pH of 3.9.

[0104] <Etching rate gravimetric method>

[0105] A 100 mm x 100 mm test piece was cut out from the electroplated copper substrate. After the test piece was immersed in a 6.25 wt % sulfuric acid aqueous solution and shaken for 30 seconds, it was washed and dried. That is, the test piece was derusted. It was used as a test piece to confirm the etching rate (hereinafter referred to as the "etching rate confirmation test piece"). The weight of the etching rate confirmation test piece was measured using a precision balance with 4 decimal places (hereinafter referred to as the "weight before washing"). The etching rate confirmation test piece was immersed in a cleaning solution at 30°C and shaken for 60 seconds. After being taken out of the cleaning solution, it was immediately washed with water and dried using a dryer. Subsequently, the weight of the etching rate confirmation test piece was measured using a precision balance with 4 decimal places (hereinafter referred to as the "weight after washing").

[0106] The difference between the weight before and after cleaning is calculated, that is, the weight change before and after cleaning. Based on the weight change and the etching rate, the area of ​​the test piece and the density of copper are confirmed to calculate the etching depth. Specifically, the etching depth is calculated according to the following formula.

[0107] Etching depth (cm) = weight change (g) ÷ area (cm 2 )÷density(g / cm 3 )

[0108] Furthermore, the density of copper is set to 8.92 g / cm 3 Since the electroplated copper substrate is a double-sided board, the area of ​​the etching rate confirmation test piece is set to 200 cm 2 The etching depth is calculated.

[0109] Based on the etching depth, the etching rate (μm / min) was calculated.

[0110] <Etching rate copper wafer fluorescence X-ray analysis>

[0111] Prepare a substrate on which a copper sputtering layer with a thickness of 2000 angstroms is formed on a silicon wafer. That is, prepare a substrate having a silicon wafer and a copper sputtering layer with a thickness of 2000 angstroms. Cut a test piece of about 10 mm x about 10 mm from the substrate. Shake the test piece for 60 seconds while immersing it in a cleaning solution at 30°C, wash it with water immediately after taking it out of the cleaning solution, and dry it in a dryer. For the test piece, use a fluorescent X-ray analyzer (manufactured by Hitachi High-Tech) to measure the strength of copper and calculate the thickness of the copper sputtering layer. Calculate the etching rate (nm / min) based on the calculation result.

[0112] <Removability of Copper Oxide>

[0113] After heating the electroplated copper substrate at 150°C for 1 hour (i.e., baking), a 50mm×50mm test piece was cut out. The test piece was shaken for 60 seconds while being immersed in a cleaning solution at 30°C, and immediately washed with water after being taken out of the cleaning solution, and dried in a dryer. For the test piece, a colorimeter (CR-10Plus manufactured by KONICA MINOLTA) was used to measure L* (hereinafter sometimes referred to as "L value"). The higher the L value, the greater the degree of removal of copper oxide. Furthermore, according to the results of preliminary experiments, it is believed that a cleaning solution that can make the L value above 78 has a cleaning effect (specifically, a rust removal effect) equivalent to or greater than 6.25 wt% sulfuric acid. Whether the test piece is rust-free is also evaluated by visual inspection. Furthermore, since the area where rust remains (i.e., the rust area) is darker, the color tone appears uneven. In the case of unevenness, it is judged to be rusty. The cases judged to have rust were marked as ×, and the cases judged to have no rust were marked as ○, and the results are shown in the table.

[0114] <Detergency of organic matter>

[0115] A solution (hereinafter referred to as "FE solution") is prepared by dissolving these substances in ion exchange water in such a manner as to become 6.25 wt % sulfuric acid, 3.5 wt % hydrogen peroxide, and 0.1 wt % 5-aminotetrazole. On the other hand, a 300 mm × 300 mm test piece is cut out from the electroplated copper substrate. The test piece is immersed in a 25°C FE solution for 30 seconds, and then washed and dried. The test piece (i.e., the test piece treated with FE solution) is cut into 50 mm × 50 mm, and the infrared absorption spectrum is measured by a Fourier transform infrared spectrophotometer (FT-IR) and a reflection absorption method (RAS method) (the measurement conditions will be described later). The test piece treated with FE solution is shaken for 60 seconds while being immersed in a cleaning solution at 30°C, and immediately washed with water after being taken out of the cleaning solution, and dried using a dryer (i.e., the test piece treated with FE solution is cleaned). Then, the infrared absorption spectrum of the test piece (i.e., the test piece after cleaning) was also measured by FT-IR and RAS method. -1 The peak area near 3350cm in the infrared absorption spectrum after washing -1 The peak area near , and the degree of cleaning was calculated according to the following formula. The larger the value of the degree of cleaning, the better the removal of organic residues.

[0116] Cleaning degree = {(peak area before cleaning - peak area after cleaning) / peak area before cleaning} × 100

[0117] Infrared absorption spectra (specifically, both infrared absorption spectra before and after cleaning) were obtained by reflection absorption method (RAS method) using "NICOLET380" manufactured by Thermo Fisher Scientific with detector: DLaTGS / KBr, accessories: RAS, resolution: 8 cm -1 , cumulative number of times: 16 times, incident angle: 75 degrees.

[0118] Regarding the peak area (i.e. 3350cm -1 The calculation of the peak area near the peak is based on the infrared absorption spectrum with the wave number as the horizontal axis and the absorbance as the vertical axis, with the connecting wave number of 3263 cm -1 The determination point and wave number are 3529cm -1 The straight line of the measuring point was taken as the baseline, and the area of ​​the region enclosed by the baseline and the curve of the infrared absorption spectrum was calculated as the peak area of ​​the organic residue (i.e., 3350 cm -1 nearby peak area).

[0119] [Table 1]

[0120]

[0121] [Table 2]

[0122]

[0123]

[0124] [Table 3]

[0125]

[0126] In Comparative Example 1, which used a cleaning solution containing malic acid and no hydrogen peroxide, although the removal of copper oxide was good, the cleaning of organic matter was not good. In Comparative Example 2, which used a cleaning solution containing hydrogen peroxide and no malic acid, the removal of copper oxide and the cleaning of organic matter were poor. In Comparative Example 3, which used a cleaning solution containing malic acid and hydrogen peroxide with a pH value of 3.9, the removal of copper oxide was not good. In Comparative Example 6, which used a cleaning solution containing malic acid and 1.00 wt% hydrogen peroxide, although the removal of copper oxide and the cleaning of organic matter were good, the etching rate was too high. In Comparative Example 7, which used a cleaning solution containing malic acid and 4.00 wt% hydrogen peroxide, although the removal of copper oxide and the cleaning of organic matter were good, the etching rate was too high.

[0127] On the other hand, in Examples 1 to 54, the removal property of copper oxide and the cleaning property of organic matter were good, and the etching rate was not too high.

[0128] <Resin Adhesion>

[0129] A 100 mm x 100 mm test piece was cut out from the electroplated copper foil, and the surface of the test piece was treated with a flash etching solution from MEC Co., Ltd., and then washed with water and dried. The flash etching solution contained a nitrogen-containing heterocyclic compound.

[0130] The test piece (i.e., the flash-etched test piece) is immersed in a cleaning solution at 30°C (specifically, the cleaning solution prepared in Examples 11, 52, 53, 54 and Comparative Example 1), shaken in this state for 60 seconds, taken out of the cleaning solution, immediately rinsed with water, and dried in a dryer.

[0131] The test piece (i.e., the cleaned test piece) was immersed in a film-forming liquid (the preparation method will be described later) at 25°C, shaken for 60 seconds, and immediately washed with water after being taken out of the film-forming liquid, and dried in a dryer. For the test piece (i.e., the test piece treated with film formation), the infrared absorption spectrum at 1100 cm -1 The peak area of ​​Si-O nearby (the measurement conditions will be described later).

[0132] After the test piece treated with film formation is heated at 130°C for 60 minutes in the atmosphere to thermally degrade it, a build-up film ("ABF" manufactured by Ajinomoto Fine-Techno) is vacuum laminated to the test piece (i.e., the test piece after thermal degradation) and then heated under recommended conditions. The build-up film is thereby thermally hardened. Through this sequence of steps, a resin layer (i.e., a hardened build-up film) is formed on one side of the copper foil treated with film formation. A 10 mm wide incision is made into the copper foil from the side opposite to the side on which the resin layer is formed, and the front end of the copper foil is fixed with a clamp. A 90° peel test is performed at a peeling speed of 50 mm / min for a length of 6 mm in accordance with JIS C6481 to determine the peel strength.

[0133] The film forming solution was prepared by the method described in Example 5 of Japanese Patent No. 6779557. Specifically, 0.4 wt% of 3-(2-aminoethylamino)propyltrimethoxysilane, CuSO 4 ·5H 2 A film-forming solution was prepared by dissolving 0.2 wt% O and 0.3 wt% KBr in ion-exchanged water and adjusting the pH to 5.0.

[0134] Infrared absorption spectroscopy was performed using the "NICOLET380" manufactured by Thermo Fisher Scientific by the reflection absorption method (RAS method) with detector: DLaTGS / KBr, accessories: RAS, resolution: 8 cm -1 , cumulative number of times: 16 times, incident angle: 75 degrees.

[0135] The calculation of the peak area of ​​Si-O is based on the infrared absorption spectrum with the wave number as the horizontal axis and the absorbance as the vertical axis, with the connecting wave number at 1070 cm -1 The measurement point and wave number are 1180cm -1 The straight line of the measurement points is taken as the baseline, and the area of ​​the region enclosed by the baseline and the curve of the infrared absorption spectrum is calculated as the peak area of ​​Si—O.

[0136] [Table 4]

[0137]

[0138] When cleaning was performed using a cleaning solution having good copper oxide removal performance and organic matter cleaning performance (specifically, the cleaning solutions prepared in Examples 11, 52, 53, and 54), the peel strength was excellent. On the other hand, when cleaning was performed using a cleaning solution having poor organic matter cleaning performance compared to the cleaning solutions prepared in these Examples (specifically, Examples 11, 52, 53, and 54) (specifically, the cleaning solution prepared in Comparative Example 1), the peel strength was poor. Furthermore, in Examples 11, 52, 53, 54, and Comparative Example 1, the peak of Si-O was confirmed, and it was determined that the film was formed using the film forming solution.

Claims

1. A cleaning agent for a substrate including copper wiring, comprising a water-soluble carboxylic acid, and Hydrogen peroxide, The concentration of the hydrogen peroxide is less than 0.75% by weight, and The pH value of the above detergents is less than 2.

5.

2. The cleaning agent according to claim 1, which does not substantially contain nitrogen-containing heterocyclic compounds.

3. The cleaning agent according to claim 1, which does not contain a nitrogen-containing heterocyclic compound.

4. The cleaning agent according to claim 1, wherein The water-soluble carboxylic acid is at least one carboxylic acid selected from the group consisting of formic acid, acetic acid, propionic acid, glycolic acid, oxalic acid, malonic acid, succinic acid, maleic acid, lactic acid, malic acid, citric acid, glycine, α-alanine and β-alanine.

5. The cleaning agent according to claim 1, wherein The concentration of the water-soluble carboxylic acid is 0.2% by weight or more.

6. The cleaning agent according to claim 1, wherein The concentration of the hydrogen peroxide is 0.05% by weight or more.

7. The cleaning agent according to claim 1, wherein the chloride ion concentration is 0.05 ppm or more.

8. The cleaning agent according to claim 1, which is used for cleaning the substrate before forming a film for improving the adhesion between the copper wiring and the resin member on the surface of the copper wiring. 9 . A cleaning method comprising the step of cleaning a substrate including copper wiring using the cleaning agent according to claim 1 .

10. A replenishing liquid which is added to the detergent according to any one of claims 1 to 8 when the detergent is used continuously or repeatedly. The replenishing solution comprises a water-soluble carboxylic acid, and Hydrogen peroxide, and The pH value did not reach 2.5.

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