Basic aqueous etching composition for treating the surface of metal substrates

Abstract

The present invention provides a basic aqueous etching composition for treating the surface of a metal substrate, the composition comprising: (a) a compound represented by Formulas I and II, wherein X and Y are independently oxygen, NRR′ and NR 5 wherein R, R' and R 5 are independently 1 , hydrogen, polyethylene glycol, aromatic compounds and C1-C4 alkyl, wherein the aromatic compounds and C1-C4 alkyl are optionally selected from the group consisting of OR 6 and R 6 is selected from the group consisting of hydrogen and C1-C4 alkyl, X and Y may be the same or different, R 1 and R 2 are independently selected from the group consisting of hydrogen, alkyl compounds, amines, and nitrogen-containing heteroaromatic compounds; R 1 and R 2 may be the same or different, except that R 1 must not be hydrogen, and in compounds having formula (I), when X is oxygen, R 1 and (b) an oxidizing agent for oxidizing the metal on the surface of a metal to be treated, wherein the basic aqueous etching composition has a pH of 7.1 to 14.

Description

[Technical Field]

[0001] The present invention according to a first aspect relates to a basic aqueous etching composition for the surface treatment of metal substrates, in particular for the surface treatment of silver, copper, nickel and / or cobalt.

[0002] According to a second aspect, the present invention further relates to a method for treating a metal substrate surface, in particular a silver, copper, nickel and / or cobalt surface, with a basic aqueous etching composition according to the first aspect.

[0003] According to a third aspect, the present invention further relates to a metal substrate having an etched surface, in particular a silver, copper, nickel and / or cobalt surface, wherein the etched surface of the metal substrate has been obtained by the method for treating a metal substrate surface according to the second aspect.

[0004] Background of the Invention In the manufacture of printed circuit boards, copper surface treatment is performed before the copper surface is coated with a dry film such as an etching photoresist or solder resist to promote adhesion between the copper surface and the resist. Polishing methods can include mechanical polishing, such as buffing, and chemical polishing. Chemical polishing is typically used to treat substrates with fine wiring patterns. In the manufacture of multilayer printed circuit boards, attempts have been made to promote adhesion between the copper conductive pattern layer and the resin layer by, for example, forming an oxide film on the copper surface and then reducing the oxide film to metallic copper using a reducing agent while maintaining the geometric shape of the oxide film.

[0005] Copper surfaces typically discolor when subjected to oxidation treatments. The desired color of an etched copper surface is slightly reddish to brownish and lacks luster. This color is generally associated with a certain roughness that provides good laminate adhesion. However, the desired color change also varies depending on the application. A reddish color is desired for copper layers present on the exterior of a laminate (e.g., dry film or soldermask applications), while darker colors may be acceptable in multilayer applications where the treated copper surface is held within an organic matrix. This color change can also be explained by the formation of a copper oxide film or organocopper complexes on the surface. Since many in-line analyzers focus on the color of the copper surface, other discolorations are undesirable and can result in scrap during production.

[0006] A further limitation of many methods described in the art is the occurrence of undesirable undercutting when depositing a final finish such as electroless tin or ENIG (electroless nickel immersion gold) onto an etched copper surface that already has a solder mask or photoresist, which can be the result of poor adhesion between the copper surface and the organic matrix.

[0007] Typically, it is desirable for an organic matrix deposited on an etched copper surface to have rectangular edges. If either the deposition of the organic matrix itself or the metal plating process leaves such edges at odd angles that form a wedge-like feature visible in, for example, a cross section of the organic matrix, this is called undercut.

[0008] U.S. Patent Application Publication No. 2018 / 0312978 discloses a surface treatment solution for copper and copper alloy surfaces and a method for treating copper or copper alloy surfaces, the surface treatment solution including an acid, an oxidizing agent selected from the group consisting of hydrogen peroxide, metal peroxides, metal superoxides, and mixtures thereof, at least one chloride ion source, and at least one bromide ion source.

[0009] WO 02 / 04706 discloses an acidic treatment solution and method for treating copper surfaces, which solution comprises hydrogen peroxide, at least one five-membered heterocyclic compound, and at least one microstructure modifier selected from the group consisting of thiols, disulfides, sulfides, and thioamides.

[0010] EP 2248402 discloses a non-etching non-resist adhesive composition and a method for producing a workpiece, which comprises at least one adhesive selected from the group consisting of heterocyclic compounds containing at least one thiol moiety, acrylic compounds, and quaternary ammonium polymers.

[0011] US Pat. No. 3,809,588 discloses an etchant useful for etching copper which comprises a peroxy-containing compound, a copper complexing agent, and an etchant stabilizer.

[0012] However, some conventional methods and processing solutions are unable to effectively etch a wide variety of metal surfaces, such as silver, copper, nickel and / or cobalt surfaces, at sufficiently efficient etch rates.

[0013] Furthermore, conventional methods and treatment solutions may not be able to achieve a sufficiently advantageous roughness of the treated surface, and subsequent deposition of additional metal or resin structures on such etched surfaces may not work well.

[0014] Object of the invention It was therefore a first object of the present invention to provide an etching composition for the treatment of metal substrate surfaces and a method for treating metal substrate surfaces, which allows efficient etching of the treated metal surfaces, particularly effective, in particular at a constant etching rate.

[0015] It was therefore a second object of the present invention to provide an etching composition for the treatment of metal substrate surfaces, and a method for treating metal substrate surfaces, which can be used for the treatment of a number of different metal or metal alloy surfaces, such as silver, palladium, copper, nickel, cobalt, manganese, zinc, lead, antimony, tin, rare earth metals, such as neodymium, copper-zinc alloys, copper-tin alloys, copper-nickel alloys and / or aluminum-magnesium alloy surfaces, in particular silver, copper, nickel and / or cobalt surfaces.

[0016] It was therefore a third object of the present invention to provide an etching composition for the treatment of metal surfaces and a method for treating metal surfaces, which provides an effective roughening of the treated metal surface, allowing for the efficient subsequent deposition of additional layers, in particular the production of opaque surfaces.

[0017] It was therefore a fourth object of the present invention to provide an etching composition for the surface treatment of metal substrates and a method for the treatment of metal substrate surfaces that can be used to treat a number of different metal substrates, for example, on the one hand, for the treatment of large areas of metal surfaces in the technical field of general manufacturing, and on the other hand, for the treatment of fine structures on printed circuit boards in the technical field of electronics.

[0018] Therefore, a fifth object of the present invention was an etching composition for the treatment of metal substrate surfaces and a method for treating metal substrate surfaces, which allows the etching composition to be regenerated, resulting in an environmentally friendly and cost-effective process.

[0019] Therefore, a sixth object of the present invention was to provide an etching composition for treating the surface of a metal substrate, and a method for treating the surface of a metal substrate, which effectively stabilizes metal ions removed from each metal surface by etching in the etching composition to prevent precipitation.

[0020] It was therefore a seventh object of the present invention to provide an etching composition for the treatment of metal surfaces, and a method for treating metal surfaces, in which the additional layer subsequently deposited on the treated metal surface has excellent functional and / or decorative qualities.

[0021] It was therefore an eighth object of the present invention to provide an etching composition for the treatment of metal surfaces and a method for treating metal surfaces, which comprises compounds with reduced toxicity.

[0022] Summary of the Invention The above first to eighth objects are, according to a first aspect, a basic aqueous etching composition for treating a surface of a metal substrate, the composition comprising: (a) Formulas I and II [ka] [In the formula, X and Y are independently oxygen, NRR′ and NR 5 and selected from the group comprising: R, R' and R 5 are independently 1 , hydrogen, polyethylene glycol, aromatic compounds and C1-C4 alkyl, wherein the aromatic compounds and C1-C4 alkyl are optionally selected from the group consisting of OR 6 and wherein the at least one substituent is selected from R 6 is selected from the group consisting of hydrogen and C1-C4 alkyl; X and Y may be the same or different; R 1 and R 2 is independently selected from the group consisting of hydrogen, alkyl compounds, amines, and nitrogen-containing heteroaromatic compounds; R 1 and R 2 may be the same or different, except that R 1 must not be hydrogen, In compounds having formula I, when X is oxygen, R 1 must not be hydrogen or an alkyl compound; m is an integer of 1 to 4, preferably 3; n is an integer of 0 to 8, preferably 2 to 4; wherein m and n may be the same or different, but n and m cannot be 0 at the same time, and / or a salt thereof, and (b) an oxidizing agent for oxidizing the metal on the surface of the metal to be treated; Including, The basic aqueous etching composition has a pH of 7.1 to 14, preferably 8 to 12.

[0023] A basic aqueous etching composition for the surface treatment of metal substrates allows for efficient etching of a wide variety of metal surfaces with optimized etch rates.

[0024] In particular, the basic aqueous etching compositions are those that allow for efficient etching of silver, palladium, copper, nickel, cobalt, manganese, zinc, lead, antimony, tin, rare earth metals such as neodymium, copper-zinc alloys, copper-tin alloys, copper-nickel alloys, and / or aluminum-magnesium alloy surfaces, especially silver, copper, nickel and / or cobalt surfaces.

[0025] Furthermore, the basic aqueous etching composition ensures that an efficient, particularly constant, etching rate is maintained during the etching process. An efficient etching rate allows for efficient removal of metal from the metal surface during the etching process, thereby minimizing material consumption. An efficient etching process is particularly characterized by a constant etching rate, which allows for uniform removal of metal from the metal surface during the etching process, resulting in a uniform metal surface obtained after the etching process.

[0026] Furthermore, the basic aqueous etching composition allows for effective roughening of the treated metal surface, which results in improved adhesion of additional layers subsequently deposited on the treated metal surface, and such effective roughness of the treated metal surface can be transferred to the additional deposited layer, resulting in the additional deposited layer also having high roughness, thereby providing the desired opaque color of the additional deposited layer.

[0027] Furthermore, the basic aqueous etching compositions can be applied to the treatment of a variety of different metal substrates, including large surface areas in the general manufacturing technology field, and fine surface areas, such as printed circuit boards in the electronics technology field.

[0028] Furthermore, the functionalized urea, biuret and guanidine derivatives and / or salts thereof selected from the group comprising compounds having formulas I and II of the basic aqueous etching composition can efficiently stabilize metal ions removed from the treated metal surface within the composition, particularly by chelation, thereby minimizing the tendency of said metal ions to precipitate.

[0029] In particular, the basic aqueous etching compositions do not require the addition of further complexing or stabilizing agents, and preferably do not explicitly include additional complexing or stabilizing agents to stabilize the resulting metal ions, because the functionalized urea, biuret, and guanidine derivatives according to the present invention are capable of simultaneously etching the metal and chelating the resulting metal ions.

[0030] Additionally, the compounds of formulas I and II are less toxic than other etching compounds previously used in the prior art.

[0031] An additional particular advantage of the basic aqueous etching composition according to the first aspect is that the compounds of the composition can be regenerated, allowing for an environmentally friendly and cost-effective process.

[0032] The above first to eighth objects are achieved by a second aspect of a method for treating a surface of a metal substrate, comprising: (A) providing the metal substrate; (B) providing a basic aqueous etching composition for treating a metal substrate surface according to the first aspect; (C) contacting a metal substrate with the basic aqueous etching composition to etch the surface of the metal substrate; This is achieved by a method comprising:

[0033] The treatment method allows for better etching of the surface of the treated metal substrate.

[0034] According to a third aspect, the above first to eighth objects are achieved by a metal substrate having an etched surface, wherein the etched surface of the metal substrate is obtained by the method for treating a metal substrate surface according to the second aspect.

[0035] The metal substrate provides an effective etching surface.

[0036] Brief description of the table Tables 1 and 2 show the general correlations between the etching performance, expressed as etching efficiency, obtained after etching a copper substrate surface using various basic aqueous etching compositions with functionalized urea, biuret, and guanidine compounds at varying pH values, where columns (C1), (C2), and (E1)-(E7), and columns (C3), (C4), and (E8)-(E18) represent different basic aqueous etching compositions.

[0037] Table 3 shows the etched surfaces of the copper substrates obtained after etching the copper substrate surfaces using the basic aqueous etching compositions in Table 1, as well as the surface roughness S Q The roughness of each etching surface is shown in the figure.

[0038] Further details are provided in the Examples section herein below.

[0039] Detailed Description of the Invention In the context of the present invention, the terms "at least one" or "one or more" refer to (and are interchangeable with) "one, two, or more than two."

[0040] C according to the present invention x ~C y The term refers to a substance containing from X carbon atoms to Y carbon atoms. For example, the term C1-C6 alkyl refers to an alkyl compound containing from 1 carbon atom to 6 carbon atoms.

[0041] According to a first aspect, the present invention provides a basic aqueous etching composition for treating a surface of a metal substrate, the composition comprising: (a) Formulas I and II [ka] [In the formula, X and Y are independently oxygen, NRR′ and NR 5 and selected from the group comprising: R, R' and R 5 are independently 1 , hydrogen, polyethylene glycol, aromatic compounds and C1-C4 alkyl, wherein the aromatic compounds and C1-C4 alkyl are optionally selected from the group consisting of OR 6 and wherein the at least one substituent is selected from R 6 is selected from the group consisting of hydrogen and C1-C4 alkyl; X and Y may be the same or different; R 1 and R 2 is independently selected from the group consisting of hydrogen, alkyl compounds, amines, and nitrogen-containing heteroaromatic compounds; R 1 and R 2 may be the same or different, except that R 1 must not be hydrogen, Additionally, in compounds having formula I, when X is oxygen, R 1 must not be an alkyl compound, m is an integer of 1 to 4, preferably 3; n is an integer of 0 to 8, preferably 2 to 4; wherein m and n may be the same or different, but n and m cannot be 0 at the same time, and / or a salt thereof, and (b) an oxidizing agent for oxidizing the metal on the surface of the metal to be treated; Including, The basic aqueous etching composition has a pH of 7.1 to 14, preferably 8 to 12.

[0042] In one embodiment of the present invention, the basic aqueous etching composition comprises functionalized urea, biuret, and guanidine derivatives and / or salts thereof selected from the group consisting of compounds having formulas I and II and / or salts thereof, and an oxidizing agent for oxidizing the metal on the surface of the metal to be treated, and the basic aqueous etching composition has a pH of 7.1 to 14, preferably 8 to 12, as described above. Preferably, the oxidizing agent comprises atmospheric oxygen dissolved in the basic aqueous etching composition.

[0043] According to a first aspect, the substituent R 1 and R 2 are independently selected from the group including, in particular, hydrogen, and the substituents of compounds of formula I or II may be the same or different, with the proviso that R 1 must not be hydrogen. This is because the substituent R 2 can be selected as hydrogen, but the substituent R 1 cannot be selected as hydrogen, thereby excluding, for example, methylurea, H2N-CO-NH-CH3, from being included in compounds of formula I.

[0044] According to a first aspect, the substituent R 1and R 2 are independently selected from the group comprising, in particular, alkyl compounds, which may be branched or unbranched, and which are preferably unsubstituted or contain substituents, in particular ether substituents, with the further proviso that in compounds having formula I, when X is oxygen, R 1 must not be an alkyl compound. 2 can be selected as hydrogen or alkyl compounds, but the substituent R 1 cannot be selected as methyl, ethyl, etc., thereby also excluding, for example, ethylurea, N,N'-dimethylurea, or N,N'-diethylurea from being included in the compounds of formula I.

[0045] In the basic aqueous etching compositions of the present invention, the functionalized biuret derivatives and / or salts thereof are selected as compounds and / or salts thereof having formula II, with the proviso that when X and Y are oxygen, R 1 Preferably, the aryl group should not be an alkyl compound, thereby excluding, for example, ethyl biuret from being included in the compound of formula II.

[0046] In the basic aqueous etching compositions of the present invention, functionalized urea and biuret derivatives and / or salts thereof are selected as compounds and / or salts thereof having formula I or II, with the proviso that when X and Y are oxygen, R 1 and R 2 Preferably, N,N'-dimethylurea or N,N'-dimethylbiuret are not included in the compounds of formula I or II.

[0047] According to a first aspect, the substituent R 1 and R 2are independently selected from the group comprising, in particular, amines, said amines preferably comprising primary, secondary and / or tertiary amines, said amines more preferably comprising alkyl-substituted amines, or aminoalkyl-substituted amines, or alkyl-substituted amines, wherein the alkyl group further comprises an additional functionalized urea substituent.

[0048] According to a first aspect, the substituent R 1 and R 2 are independently selected from the group comprising, in particular, nitrogen-containing heteroaromatic compounds, and the nitrogen-containing heteroaromatic compounds are preferably 4- to 10-membered heteroaromatic compounds containing 1 to 4 nitrogen atoms.

[0049] One of the advantages achieved by the basic aqueous etching composition according to the first aspect of the present invention is that a number of metal surfaces, in particular silver, copper, nickel and / or cobalt surfaces, are efficiently etched, in particular at a constant etching rate in [μm / h]. A constant etching efficiency, i.e. a constant etching rate, results in a uniformly etched metal surface.

[0050] Depending on the type and thickness of the substrate metal, the etching efficiency, which is correlated with the etching rate [μm / h], can be adjusted to a higher or lower etching efficiency by selecting the desired compound of formula I and / or II.

[0051] By applying the basic aqueous etching composition according to the first aspect of the present invention, an effective roughening of the treated metal surface can be achieved, which allows for efficient adhesion of any additional layers deposited on the treated surface of the etched metal substrate, thereby ensuring the desired opaque color of the additional layers.

[0052] In particular, the basic aqueous etching composition is recyclable, which limits material consumption and ensures a cost-effective and environmentally friendly process.

[0053] Furthermore, due to the nitrogen functionality present in the functionalized urea, biuret and guanidine derivatives having formulas I and II, highly efficient stabilization of the metal ions in the composition can be achieved by chelation of said metal ions, resulting in a reduced tendency of said metal ions to precipitate.

[0054] Preferably, functionalized urea, biuret and guanidine derivatives and / or salts thereof are selected as compounds having formula I and / or salts thereof.

[0055] The etching composition is a basic aqueous etching composition, preferably comprising more than 50% by volume of water, more preferably 75% by volume or more, even more preferably 85% by volume or more, even more preferably 90% by volume or more, even more preferably 95% by volume or more, and most preferably 99% by volume or more of water, based on the total volume of the basic aqueous etching composition. Preferably, water is the only solvent in the basic aqueous etching composition.

[0056] Preferably, the oxidizing agent for oxidizing the metal on the treated metal surface comprises dissolved oxygen in the basic aqueous etching composition.

[0057] Preferably, the dissolved oxygen in the basic aqueous etching composition comes from atmospheric oxygen diffusing into the basic aqueous etching composition from the ambient air.

[0058] The use of oxygen, particularly atmospheric oxygen that naturally diffuses from ambient air into the basic aqueous etching composition, allows for a sufficient concentration of oxidizing agent to be maintained in the composition for an extended period of time, thereby enabling efficient oxidation of the metal on the treated metal surface without the need for manual addition of additional oxidizing agent to the composition. In particular, the basic aqueous etching composition of the present invention is preferably capable of etching without additional oxidizing agent (other than dissolved atmospheric oxygen). Additional oxidizing agent is added only to enhance the etching rate, if desired, but is not required to initiate or maintain the etching process of the present invention.

[0059] In the basic aqueous etching composition of the present invention, X is selected from the group consisting of oxygen and NR 5 Preferably, the compound is selected from the group comprising: R 5 is R 1 , hydrogen, polyethylene glycol, aromatic compounds, and C1-C4 alkyl, wherein the aromatic compounds and C1-C4 alkyl are optionally selected from the group consisting of OR 6 and R 6 is selected from the group consisting of hydrogen and C1-C4 alkyl; Preferably, R 5 is selected from the group consisting of hydrogen and C1-C4 alkyl; More preferably, R 5 is selected from the group consisting of hydrogen and C1-C3 alkyl; Even more preferably, R 5 is selected from the group consisting of hydrogen and C1 or C2 alkyl; Most preferably, R 5 is selected from the group comprising hydrogen and methyl.

[0060] In the basic aqueous etching composition of the present invention, X is preferably selected from the group comprising oxygen and NH, and X is preferably oxygen.

[0061] In the basic aqueous etching composition of the present invention, functionalized urea, biuret and guanidine derivatives and / or salts thereof are preferably selected as compounds and / or salts thereof having formula II, wherein Y is selected from the group comprising oxygen and NRR″, R and R″ are independently R 1 , hydrogen, polyethylene glycol, aromatic compounds, and C1-C4 alkyl, wherein the aromatic compounds and C1-C4 alkyl are optionally selected from the group consisting of OR 6 and R 6 is selected from the group consisting of hydrogen and C1-C3 alkyl; Preferably, R and R″ are independently selected from the group comprising hydrogen and C1-C4 alkyl; More preferably, R and R″ are independently selected from the group comprising hydrogen and C1-C3 alkyl; Even more preferably, R and R″ are independently selected from the group comprising hydrogen and C1 or C2 alkyl; Most preferably, R and R'' are independently selected from the group comprising hydrogen and methyl.

[0062] In the basic aqueous etching composition of the present invention, functionalized urea, biuret and guanidine derivatives and / or salts thereof are selected as the compound having formula II and / or salts thereof, and Y is preferably selected from the group comprising oxygen and NH, and Y is preferably oxygen.

[0063] In the basic aqueous etching composition of the present invention, R 2 is preferably selected as hydrogen.

[0064] In the basic aqueous etching composition of the present invention, R 1 and R 2 is preferably selected as an alkyl compound which may be branched or unbranched, preferably as a C1-C6 alkyl, more preferably as a C1-C4 alkyl, even more preferably as a C2 or C3 alkyl, most preferably as isopropyl or isopentyl.

[0065] Preferably, when the parameter n is selected as 0, the substituent R 2 is -O-(C1-C6 alkyl)-NH-CO-NH-(C1-C6 alkyl)-NR 7 R 8 and R is selected as a C1-C6 alkyl having one substituent selected as 7 and R 8 is independently selected from hydrogen and C1-C6 alkyl.

[0066] More preferably, when the parameter n is selected as 0, the substituent R 2 is -O-(C1-C3 alkyl)-NH-CO-NH-(C1-C3 alkyl)-NR 7 R 8 and R is selected as a C1-C3 alkyl having one substituent selected as 7 and R 8 is independently selected from C1 to C3 alkyl.

[0067] Even more preferably, when the parameter n is selected as 0, the substituent R 2 is -O-(C3 alkyl)-NH-CO-NH-(C3 alkyl)-NR 7 R 8 R is selected as isopropyl containing one substituent selected as 7 and R 8 are both selected from C1-C3 alkyl.

[0068] In the basic aqueous etching composition of the present invention, R 1 and R 2 are preferably selected as alkyl compounds which may be branched or unbranched, preferably as C1-C6 alkyl, more preferably as C1-C4 alkyl, even more preferably as C2 or C3 alkyl, most preferably as isopropyl or isopentyl.

[0069] In the basic aqueous etching composition of the present invention, R 1 and R 2 At least one of the following is NH2, NHR 3 and N.R. 3 R 4 Preferably, the compound is selected from the group comprising: R 3 and R 4 are independently C1 to C 16 alkyl, 5- to 16-membered aryl, and 5- to 16-membered heteroaryl, which may optionally be selected from the group consisting of OR 6 [where R 6is selected from the group consisting of hydrogen and C1-C6 alkyl, NR 7 R 8 [where R 7 and R 8 are both independently selected as hydrogen or C1-C6 alkyl], and NH-CO-NH-(CH2) o -NR 9 R 10 where o is selected as an integer between 0 and 4, and R 9 and R 10 are both independently selected as hydrogen or C1-C6 alkyl; Preferably, R 3 and R 4 are independently C1 to C 10 alkyl, 5- to 10-membered aryl, and 5- to 10-membered heteroaryl, which optionally includes OR 6 [where R 6 is selected from the group consisting of hydrogen and C1-C6 alkyl, NR 7 R 8 [where R 7 and R 8 are both independently selected as hydrogen or C1-C6 alkyl], and NH-CO-NH-(CH2) o -NR 9 R 10 where o is selected as an integer between 0 and 4, and R 9 and R 10 are both independently selected as hydrogen or C1-C6 alkyl; More preferably, R 3 and R 4 is independently selected from the group consisting of C1-C6 alkyl, 5-6 membered aryl and 5-6 membered heteroaryl, which optionally can be selected from OR 6 [where R 6 is selected from the group consisting of hydrogen and C1-C3 alkyl, NR 7 R 8 [where R 7 and R 8are both independently selected as hydrogen or C1-C6 alkyl], and NH-CO-NH-(CH2) o -NR 9 R 10 where o is selected as an integer between 0 and 4, and R 9 and R 10 are both independently selected as hydrogen or C1-C6 alkyl; Even more preferably, R 3 and R 4 is independently selected from the group consisting of C1-C3 alkyl, phenyl, imidazole and pyridine, which is optionally selected from OR 6 [where R 6 is selected from the group consisting of hydrogen and C1-C3 alkyl, NR 7 R 8 [where R 7 and R 8 are both independently selected as hydrogen or C1-C6 alkyl], and NH-CO-NH-(CH2) o -NR 9 R 10 where o is selected as an integer between 0 and 4, and R 9 and R 10 are both independently selected as hydrogen or C1-C6 alkyl; Most preferably, R 3 and R 4 are independently selected as C1-C3 alkyl; Even most preferably, R 3 and R 4 is independently selected as methyl.

[0070] In the basic aqueous etching composition of the present invention, R 1 and R 2 Both NH2 and NHR 3 and N.R. 3 R 4 Preferably, the compound is selected from the group comprising: R 3 and R4 are independently C1 to C 16 alkyl, 5- to 16-membered aryl, and 5- to 16-membered heteroaryl, which may optionally be selected from the group consisting of OR 6 [where R 6 is selected from the group consisting of hydrogen and C1-C6 alkyl, NR 7 R 8 [where R 7 and R 8 are both independently selected as hydrogen or C1-C6 alkyl], and NH-CO-NH-(CH2) o -NR 9 R 10 where o is selected as an integer between 0 and 4, and R 9 and R 10 are both independently selected as hydrogen or C1-C6 alkyl; Preferably, R 3 and R 4 are independently C1 to C 10 alkyl, 5- to 10-membered aryl, and 5- to 10-membered heteroaryl, which is optionally selected from the group consisting of OR 6 [where R 6 is selected from the group consisting of hydrogen and C1-C6 alkyl, NR 7 R 8 [where R 7 and R 8 are both independently selected as hydrogen or C1-C6 alkyl], and NH-CO-NH-(CH2) o -NR 9 R 10 where o is selected as an integer between 0 and 4, and R 9 and R 10 are both independently selected as hydrogen or C1-C6 alkyl; More preferably, R 3 and R 4 is independently selected from the group consisting of C1-C6 alkyl, 5-6 membered aryl and 5-6 membered heteroaryl, which optionally can be selected from OR 6[where R 6 is selected from the group consisting of hydrogen and C1-C3 alkyl, NR 7 R 8 [where R 7 and R 8 are both independently selected as hydrogen or C1-C6 alkyl], and NH-CO-NH-(CH2) o -NR 9 R 10 where o is selected as an integer between 0 and 4, and R 9 and R 10 are both independently selected as hydrogen or C1-C6 alkyl; Even more preferably, R 3 and R 4 are independently selected from C1-C3 alkyl, phenyl, imidazole, and pyridine, which are optionally selected from OR 6 [where R 6 is selected from the group consisting of hydrogen and C1-C3 alkyl, NR 7 R 8 [where R 7 and R 8 are both independently selected as hydrogen or C1-C6 alkyl], and NH-CO-NH-(CH2) o -NR 9 R 10 where o is selected as an integer between 0 and 4, and R 9 and R 10 are both independently selected as hydrogen or C1-C6 alkyl; Most preferably, R 3 and R 4 are independently selected as C1-C3 alkyl; Even most preferably, R 3 and R 4 is independently selected as methyl.

[0071] In the basic aqueous etching composition of the present invention, R 1 and R 2Preferably, at least one of the following is selected as the nitrogen-containing heteroaromatic compound: Preferably, R 1 and R 2 At least one of is selected as a 4- to 10-membered heteroaromatic compound containing 1 to 4 nitrogen atoms, which may optionally be selected from OR 6 and C1-C4 alkyl, and R 6 is selected from the group consisting of hydrogen and C1-C3 alkyl; More preferably, R 1 and R 2 At least one of is selected as a 4-8 membered heteroaromatic compound containing 1-3 nitrogen atoms, which may optionally be selected from OR 6 and at least one substituent selected from the group including C1-C3 alkyl, and R 6 is selected from the group consisting of hydrogen and C1 or C2 alkyl; Even more preferably, R 1 and R 2 At least one of the following is selected as a 5- to 6-membered heteroaromatic compound containing 1 to 2 nitrogen atoms, which may optionally be selected from OR 6 and at least one substituent selected from the group including C1-C6 alkyl, and R 6 is selected from the group consisting of hydrogen and C1-C6 alkyl; Most preferably, R 1 and R 2 at least one of is selected from the group comprising imidazole and pyridine, which optionally comprises at least one substituent selected as C1-C6 alkyl; Even most preferably, R 1 and R 2 At least one of is selected from the group comprising imidazole and pyridine, which optionally comprises at least one substituent selected as C1-C3 alkyl.

[0072] Substituent R 1 and R 2The selection of pyridine for at least one of may include 2-pyridyl, 3-pyridyl or 4-pyridyl substitution.

[0073] In the basic aqueous etching composition of the present invention, R 1 and R 2 are preferably selected as nitrogen-containing heteroaromatic compounds, Preferably, R 1 and R 2 are both selected as 4- to 10-membered heteroaromatic compounds containing 1 to 4 nitrogen atoms, which may optionally be selected from OR 6 and C1-C4 alkyl, and R 6 is selected from the group consisting of hydrogen and C1-C3 alkyl; More preferably, R 1 and R 2 are selected as 4- to 8-membered heteroaromatic compounds containing 1 to 3 nitrogen atoms, which may optionally be selected from OR 6 and at least one substituent selected from the group including C1-C3 alkyl, and R 6 is selected from the group consisting of hydrogen and C1-C1 or C2 alkyl; Even more preferably, R 1 and R 2 are selected as 5- to 6-membered heteroaromatic compounds containing 1 to 2 nitrogen atoms, which may optionally be selected from OR 6 and at least one substituent selected from the group including C1-C6 alkyl, and R 6 is selected from the group consisting of hydrogen and C1-C6 alkyl; Most preferably, R 1 and R 2 are both selected from the group comprising imidazole and pyridine, which optionally contain at least one substituent selected as C1-C6 alkyl; Even most preferably, R 1 and R 2 are both selected from the group comprising imidazole and pyridine, which optionally contain at least one substituent selected as C1-C3 alkyl.

[0074] Substituent R 1 and R 2 The selection of pyridine for at least one of may include 2-pyridyl, 3-pyridyl or 4-pyridyl substitution.

[0075] In the basic aqueous etching composition of the present invention, n is an integer of 0 to 4, and preferably 0, 1 or 3.

[0076] In the basic aqueous etching composition of the present invention, functionalized urea, biuret and guanidine derivatives and / or salts thereof are preferably selected as compounds and / or salts thereof having formula I, wherein X is selected from the group comprising oxygen and NH, m is 3, and n is 0 or 3, R 1 is the following: (a) NH2, NHR 3 and N.R. 3 R 4 where R 3 and R 4 are independently selected as C1-C6 alkyl, preferably C1-C3 alkyl, more preferably methyl, which may optionally be selected from NR 7 R 8 [where R 7 and R 8 are both independently selected as hydrogen or C1-C6 alkyl], and NH-CO-NH-(CH2) o -NR 9 R 10 where o is selected as an integer between 0 and 4, and R 9 and R 10 are both independently selected as hydrogen or C1-C6 alkyl; (b) a 4- to 10-membered heteroaromatic compound, preferably a 5- to 6-membered heteroaromatic compound, more preferably imidazole or pyridine, optionally containing at least one substituent selected as C1-C6 alkyl; and (c) C1 to C6 alkyl, which may be branched or unbranched, preferably C1 to C4 alkyl, more preferably C2 or C3 alkyl, most preferably isopropyl or isopentyl and R 2 is the following: (a) hydrogen, (b) NH2, NHR 3 and N.R. 3 R 4 where R 3 and R 4 are independently selected as C1-C6 alkyl, preferably C1-C3 alkyl, more preferably methyl, which may optionally be selected from NR 7 R 8 [where R 7 and R 8 are both independently selected as hydrogen or C1-C6 alkyl], and NH-CO-NH-(CH2) o -NR 9 R 10 where o is selected as an integer between 0 and 4, and R 9 and R 10 are both independently selected as hydrogen or C1-C6 alkyl; (c) a 4- to 10-membered heteroaromatic compound, preferably a 5- to 6-membered heteroaromatic compound, more preferably imidazole or pyridine, optionally containing at least one substituent selected as C1-C6 alkyl; and (d) C1 to C6 alkyl, which may be branched or unbranched, preferably C1 to C4 alkyl, more preferably C2 or C3 alkyl, most preferably isopropyl or isopentyl is selected from the group comprising:

[0077] In the basic aqueous etching compositions of the present invention, functionalized urea, biuret and guanidine derivatives and / or salts thereof are preferably selected as compounds and / or salts thereof having formula I, (a) X is selected as oxygen, m and n are both selected as 3, and R 1 and R 2 are both selected as N(methyl)2, [ka] (b) X is selected as oxygen, m and n are both selected as 3, and R 1 and R 2 are both selected as imidazoles, [ka] (c) X is selected as oxygen, m and n are both selected as 1, and R 1 and R 2 are both selected as pyridine, preferably R 1 and R 2 are both selected as (c-1) 2-pyridyl, (c-2) 3-pyridyl, or (c-3) 4-pyridyl; [ka] [ka] [ka] (d) X is selected as oxygen, m is selected as 3, n is selected as 0, and R 1 is selected as N(methyl)2, and R 2 is chosen as hydrogen, [ka] (e) X is selected as NH, m and n are both selected as 3, and R 1 and R 2 are both selected as N(methyl)2, [ka] (f) X is selected as oxygen, m and n are both selected as 2, and R 1 and R 2 are both selected as N(methyl)2, [ka] (g) X is selected as oxygen, m is selected as 2, n is selected as 0, and R 1 is selected as N(methyl)2, and R 2 is chosen as hydrogen, [ka] (h) X is selected as oxygen, m and n are both selected as 3, and R 2 is selected as N(methyl)2, and R 1 is selected as -N(methyl)-(CH2)3-NH-CO-NH-(CH2)3-N(methyl)2, [ka] (i) X is selected as oxygen, m and n are both selected as 3, and R 2 is selected as N(methyl)2, and R 1 is selected as -N(methyl)-(CH2)3-NH2, and / or [ka] (j) X is selected as oxygen, n is selected as 0, m is selected as 3, j is selected as 7, and R 1 is selected as N(methyl)2, and R 2 is selected as -CH(CH3)-(CH2)-O-(CH2)-CH(CH3)-NH-CO-NH-(CH2)3-N(methyl)2. [ka]

[0078] In the basic aqueous etching composition of the present invention, functionalized urea, biuret and guanidine derivatives and / or salts thereof are preferably selected as compounds and / or salts thereof having formula II, (a) X and Y are selected as oxygen, m and n are both selected as 3, and R 1 , R 2 are both selected as N(methyl)2. [ka]

[0079] In the basic aqueous etching composition of the present invention, the oxidizing agent for oxidizing the metal on the surface of the metal to be treated contains dissolved oxygen in the basic aqueous etching composition, and the dissolved oxygen in the basic aqueous etching composition is preferably derived from atmospheric oxygen that diffuses from the ambient air into the basic aqueous etching composition.

[0080] The oxidizing agent for oxidizing the metal can be oxygen, particularly atmospheric oxygen, which facilitates a highly efficient and automatic etching reaction without the need for manual addition of additional oxidizing agent.

[0081] In the basic aqueous etching composition of the present invention, it is preferred that the composition does not contain any additional oxidizing agent other than the one oxidizing agent, which is the dissolved oxygen in the basic aqueous etching composition, and it is preferred that the composition does not contain any peroxide and / or persulfate compounds.

[0082] Eliminating the addition of an additional oxidizing agent from the basic aqueous etching composition reduces material consumption, provides uniform fine roughening of the metal surface, and prevents over-etching of the metal surface.

[0083] In the basic aqueous etching composition of the present invention, the composition preferably contains an additional oxidizing agent for oxidizing the metal on the treated metal surface, and the additional oxidizing agent is preferably selected as a peroxide and / or a persulfate compound.

[0084] The etching rate can be effectively increased by adding an additional oxidizing agent in addition to the oxidizing agent already present in the composition. In any case, the etching composition can continue etching even when the additional oxidizing agent is depleted. In particular, in the basic aqueous etching composition of the present invention, it is preferable that the etching composition can etch without an additional oxidizing agent, and the additional oxidizing agent added only improves the etching rate as needed.

[0085] The basic aqueous etching composition of the present invention preferably has a pH of 7.1 to 14, preferably 8 to 12, more preferably 9 to 11, and most preferably has a pH of 10.

[0086] By selecting the pH in a preferred range, an efficient etching process can be ensured.

[0087] In the basic aqueous etching compositions of the present invention, the compounds having formula I and II and / or salts thereof are preferably present in the composition in a total concentration of from 1 wt % to 15 wt %, preferably from 2 wt % to 14 wt %, more preferably from 3 wt % to 13 wt %, even more preferably from 4 wt % to 13 wt %, and most preferably from 5 wt % to 12.5 wt %, based on the total weight of the composition.

[0088] By selecting the concentrations of the compounds having formulas I and II in the preferred concentration range, an efficient etching process can be ensured.

[0089] In the basic aqueous etching composition of the present invention, it is preferred that the metal substrate to be treated comprises all metals and metal alloys less noble than gold, preferably excluding iron, chromium and nickel-chromium steel alloys.

[0090] In the basic aqueous etching composition of the present invention, the treated metal substrate preferably contains a metal or metal alloy selected from the group consisting of silver, palladium, copper, nickel, cobalt, manganese, zinc, lead, antimony, tin, rare earth metals such as neodymium, copper-zinc alloys, copper-tin alloys, copper-nickel alloys, and aluminum-magnesium alloys.

[0091] In the basic aqueous etching composition of the present invention, the metal substrate to be treated preferably contains silver, copper, nickel and cobalt.

[0092] As a result, the etching properties of the basic aqueous etching composition can be tailored to efficiently etch a wide variety of metal substrates.

[0093] According to a second aspect, the present invention further provides a method for treating a surface of a metal substrate, comprising the steps of: (A) providing the metal substrate; (B) providing a basic aqueous etching composition for treating a metal substrate surface according to the first aspect; (C) contacting a metal substrate with the basic aqueous etching composition to etch the surface of the metal substrate; The present invention relates to a method comprising:

[0094] The method according to the second aspect ensures an efficient etching process.

[0095] In the method of the present invention, it is preferred to carry out the method at a temperature of 20°C to 100°C, preferably 30°C to 80°C, more preferably 40°C to 60°C, and most preferably 50°C.

[0096] By carrying out the method within the preferred temperature range, a highly efficient etching reaction can be ensured.

[0097] In the method of the present invention, the metal substrate to be treated preferably comprises all metals and metal alloys less noble than gold, preferably excluding iron, chromium and nickel-chromium steel alloys.

[0098] In the method of the present invention, it is preferred that the treated metal substrate comprises a metal or metal alloy selected from the group including silver, palladium, copper, nickel, cobalt, manganese, zinc, lead, antimony, tin, rare earth metals such as neodymium, copper-zinc alloys, copper-tin alloys, copper-nickel alloys and aluminum-magnesium alloys.

[0099] In the method of the present invention, the treated metal substrate preferably comprises silver, copper, nickel and / or cobalt.

[0100] As a result, the etching efficiency of the method can be tuned to efficiently etch a wide variety of metal substrates.

[0101] In the method of the present invention, it is preferred to apply a voltage to the metal substrate in method step (C).

[0102] In the method of the present invention, the method further comprises the following steps: (D) after process step (C), recycling the basic aqueous etching composition, said step (D) comprising: (D1) increasing the temperature of the basic aqueous etching composition to obtain an elevated-temperature basic aqueous etching composition; (D2) filtering the elevated temperature basic aqueous etching composition to obtain a filtered basic aqueous etching composition; (D3) reapplying the filtered basic aqueous etching composition to method step (C); The step It is preferred that the compound contains:

[0103] As a result, the recycling step of the present method allows for efficient recovery of metals from the basic aqueous etching composition. Heating the basic aqueous etching composition causes metals to precipitate from the basic aqueous etching composition, particularly due to the disruption of chemical stabilization of the metal by the compound of Formula I or II caused by the elevated temperature. The resulting precipitate can be removed from the solution by filtration and externally processed to recover the metal.

[0104] In the method of the present invention, method step (D1) preferably comprises increasing the temperature of the basic aqueous etching composition to a temperature above 50°C, preferably above 60°C, more preferably above 70°C, most preferably above 80°C to obtain an elevated temperature basic aqueous etching composition.

[0105] By increasing the temperature of the basic aqueous etching composition above the preferred temperature, the compound of Formula I or II no longer stabilizes the respective metal ion, resulting in the precipitation of the corresponding metal salt.

[0106] In the method of the present invention, it is preferred that the precipitate formed in the basic aqueous etching composition in method step (D1) is removed from the basic aqueous etching composition in method step (D2), to obtain a filtered basic aqueous etching composition having reduced precipitates after method step (D2).

[0107] By removing the precipitate from the basic aqueous etching composition, the metal ions removed from the treated metal surface can be efficiently recovered.

[0108] In the method of the present invention, in method step (C) it is preferred to remove metal from the metal substrate surface at a constant etching rate of preferably 0.01 μm / h to 10 μm / h, more preferably 0.05 μm / h to 5 μm / h, even more preferably 0.1 μm / h to 2.5 μm / h.

[0109] A constant etching treatment, preferably at a favorable etching rate, can make the treated metal surfaces particularly uniform, thereby ensuring good surface quality of such treated metal surfaces.

[0110] In the method of the present invention, it is preferred that the metal substrate provided in step (A) comprises an opaque or rough surface.

[0111] The opaque and / or rough surface ensures good quality of the treated metal surface, especially when additional layers are deposited on the treated metal surface.

[0112] In the method of the present invention, it is preferred that the metal substrate provided in step (A) is formed as a flexible metal substrate, preferably as a flexible copper substrate, more preferably as a flexible copper-coated polymer.

[0113] In the method of the present invention, the metal substrate provided in step (A) is preferably formed as a copper clad laminate or a homogeneous copper substrate.

[0114] Etching different types of metal substrates with different chemical and physical properties allows the method to be applied to a wide range of applications and therefore can be used universally.

[0115] For example, in the case of printed circuit boards (PCBs), copper-clad resins, especially polymers, can be used as the metal substrate, as can copper-clad glass, and in general manufacturing products, copper-clad plastics and copper-clad sheet metal can be used as the metal substrate.

[0116] In the method of the present invention, steps (B) and / or (C) are preferably carried out under stirring, preferably at a stirring speed of 20 rpm to 1,000 rpm, more preferably 50 rpm to 500 rpm, and most preferably 100 rpm.

[0117] In the method of the present invention, it is preferred that step (C) is carried out in a period of less than 2 hours, preferably less than 1 hour, more preferably less than 45 minutes, even more preferably less than 30 minutes, and most preferably less than 15 minutes.

[0118] In the method of the present invention, step (C) is preferably carried out for a period of 1 minute to 2 hours, preferably 5 minutes to 1.5 hours, more preferably 15 minutes to 1 hour, and most preferably 30 minutes to 45 minutes.

[0119] The preferred agitation and time interval of the method results in an efficient etching rate that can be individually adjusted depending on the metal substrate used.

[0120] In the method of the present invention, it is preferred that the method comprises a step (P) carried out before step (C), wherein step (P) comprises: (P1) pre-rinsing the metal substrate with an acidic solution, preferably containing sulfuric acid, to obtain a pre-rinsed metal substrate; (P2) washing the pre-rinsed metal substrate with a washing liquid preferably comprising demineralized water to obtain a washed metal substrate; Including, The cleaned metal substrate is contacted with the basic aqueous etching composition in step (C).

[0121] The step of pre-rinsing the metal substrate with an acidic solution followed by washing can ensure efficient cleaning of the treated metal surface in step (C), thereby enhancing the effectiveness of the method. Pre-rinsing the substrate can efficiently remove potential corrosion of the substrate and / or contaminants on the surface of the substrate before transferring the substrate into the basic aqueous etching composition.

[0122] However, method step (P) is an optional method step and the method according to the second aspect of the invention can also be carried out without method step (P).

[0123] Preferably, the above descriptions of the basic aqueous etching composition according to the first aspect of the invention, as preferred and preferred, apply equally to the method according to the second aspect of the invention.

[0124] According to a third aspect, the present invention further relates to a metal substrate having an etched surface, wherein the etched surface of the metal substrate is obtained by the method for treating a metal substrate surface according to the second aspect.

[0125] In the substrate of the present invention, the metal substrate comprises an etched surface, and the etched surface has a roughness S of 320 to 1400. Q It is preferred that the compound has the following structure:

[0126] Roughness S Q When the SiO2 content is in the preferred range of 320 to 1400, an efficiently etched surface can be obtained, which makes it very advantageous to deposit additional layers on the etched surface.

[0127] In particular, the roughness S of the etched surface of a metal substrate Q is measured in a manner similar to ISO 25178, which allows the determination of surface roughness. In particular, the roughness S of etched surfaces of metal substrates Q was measured based on a 3D representation of the etched surface, e.g., obtained by interference microscopy of the substrate sample, but no filter was applied to the raw data, as the required filter depends on the surface properties of the corresponding etched surface.

[0128] Preferably, the above, preferably preferred, descriptions of the basic aqueous etching composition according to the first aspect of the invention and the method according to the second aspect of the invention apply equally to the substrate according to the third aspect of the invention.

[0129] Example First experimental system For the first series of experiments, aqueous test etching compositions E1-E8 were prepared (weight: approximately 10 g) containing 5 wt.% of each functionalized urea, biuret, or guanidine derivative, as outlined below. The pH ranged from 9.0 to 12.6.

[0130] Additionally, an aqueous etching composition E1a was prepared using 0.32 g of hydrogen peroxide solution (30 wt %) as an additional oxidizer.

[0131] For each test, a piece of copper foil (1 cm x 4 cm) with a chromium surface on one side that had not been pre-rinsed or pre-cleaned was immersed in each aqueous etching composition in a test tube. The test tube was supplied with an ambient atmosphere and sealed with a rubber stopper for 336 hours at 22°C. A small Teflon-coated stir bar rotated in the test tube at 100 rpm.

[0132] The etching efficiency (EE) of each aqueous etching composition was determined based on the amount of thickness reduction of the chromium-free surface of the copper foil after the reaction.

[0133] Control experiments C1 and C2 were performed, with each composition having the following additions: in control experiment C1, no functionalized urea, biuret, or guanidine derivative was added; in C1a, N,N′-dimethylurea was added; in C1b, N,N′-dimethylurea plus 0.32 g of hydrogen peroxide solution (30 wt%) as an additional oxidizing agent was added; and in control experiment C2, sulfuric acid was added to each composition to reduce the pH to less than 7.

[0134] The etching efficiency results shown in Table 1 are qualitative assessments with the following designations: +++ Excellent ++ Good + moderate - Poor [Table 1-1] [Table 1-2]

[0135] Comparing the control experiment C1, in which no functionalized urea, biuret or guanidine derivative was added, with the experiments E1 to E7, in which functionalized urea, biuret or guanidine derivative was added, it can be seen that the addition of functionalized urea, biuret or guanidine derivative is essential to obtain at least moderate, but in most cases good or excellent etching efficiency for copper foil.

[0136] Furthermore, comparing the control experiment C2, in which the composition had a pH below 7, with experiments E1-E7, in which the pH of each composition ranged from 9.0 to 12.6, it can be seen that the basic pH of each composition is also important for achieving at least moderate, but in most cases good or excellent, etching efficiency for copper foil.

[0137] However, when the etching efficiencies of Experiments E1 to E7 are compared, differences are observed.

[0138] When functionalized urea derivatives with terminal heteroaromatic substituents such as imidazole (see experiments E1 and E1a) or pyridine (see experiment E2) are used, at least good or excellent etching efficiency is observed for copper foil. Furthermore, the etching rate in experiment E1a increased by 3350%.

[0139] Although functionalized urea derivatives with terminal amine substituents still provide good etching efficiency (see Experiments E3 and E4), the corresponding functionalized guanidine derivatives with terminal amine substituents are superior (see Experiment E7), demonstrating superior etching efficiency for copper foil.

[0140] When functionalized urea or biuret derivatives with at least one terminal alkyl substituent were used (see Experiments E5 and E6), moderate etching efficiencies were observed for copper foil.

[0141] Second experimental system For the second series of experiments, aqueous test etching compositions E8-E18 were prepared (weight: approximately 20 g) containing 2.5 wt. % of each functionalized urea, biuret, or guanidine derivative, resulting in 0.5 g of each functionalized urea, biuret, or guanidine derivative in 19.5 g of water, as outlined below. The pH ranged from 8 to 13.

[0142] In each test, a copper metal plate (weight: approximately 1 g) that had been pre-rinsed in a 10 wt % aqueous solution of ammonium persulfate (APS) at 40° C. for 30 seconds and then pre-cleaned was immersed in each aqueous etching composition. The composition was supplied with an air atmosphere and stirred at 100 rpm at 45° C. for 2 weeks to cause a reaction.

[0143] Control experiments C3 and C4 were performed in which no functionalized urea, biuret, or guanidine derivative was added to each composition in control experiment C3, and sulfuric acid was added to each composition to lower the pH to below 7 in control experiment C4.

[0144] The etching efficiency (EE) of each aqueous etching composition was determined based on the amount of reduction in thickness of the copper surface of the copper foil after the reaction.

[0145] The etch efficiency (EE) results shown in Table 2 are qualitative assessments with the following designations: +++ Excellent ++ Good + moderate - Poor [Table 2-1] [Table 2-2]

[0146] From experiments E15, E16 and E17, it can be concluded that functionalized urea or biuret derivatives with terminal alkyl substituents provide appreciable, but moderate, etching efficiencies of the respective copper plates.

[0147] Similar results can be seen when functionalized urea derivatives with terminal amino groups are used (see Experiments E9 and E11), where again, acceptable but moderate to good etching efficiency of the respective copper foils can be observed.

[0148] In experiments E12, E13 and E14, various functionalized urea derivatives with terminal heteroaromatic substituents, especially pyridine, were analyzed, which showed moderate to good etching efficiency.

[0149] As shown in experiment E18, excellent etching efficiency could be observed when functionalized urea derivatives bearing terminal heteroaromatic substituents, especially imidazole, were analyzed.

[0150] Comparing the functionalized urea derivatives with terminal amine substituents shown in experiments E8 (where there is a C3 linker between the urea and the terminal amine moiety) and E10 (where there is a C2 linker between the urea and the terminal amine moiety), it appears that both the C3 linker and the C2 linker provide good etching efficiency.

[0151] Additional experimental systems To investigate the surface roughness of the etched metal surface, etched copper foil strips were analyzed by topography imaging.

[0152] Each etched copper foil strip was obtained by applying a respective basic aqueous etching composition containing a functionalized urea, biuret or guanidine derivative at basic pH according to the second experimental series (see above).

[0153] The roughness of the etched surface of each copper foil was measured similarly to ISO 25178, which allows the determination of surface roughness. The roughness of the etched surface of the metal substrate in particular was measured based on a 3D representation of the etched surface, obtained for example by interference microscopy of the substrate sample. However, no filter was applied to the raw data, as the required filter depends on the surface properties of the corresponding etched surface.

[0154] Specifically, root mean square roughness S similar to ISO 25178 Q was measured for five measurement areas of 249.6 μm × 249.6 μm size on each etched copper piece, and S Q The average value [nm] was calculated. [Table 3]

[0155] When functionalized urea derivatives with terminal alkyl substituents were used, a moderate surface roughness (see 367 nm in experiment S5, 383 nm in experiment S5) could be observed.

[0156] As derived from experiments S1, S2, S3, and S7, the highest surface roughness (1263 nm for experiment S1, 599 nm for experiment S2, 436 nm for experiment S3, and 427 nm for experiment S7) was observed when functionalized urea or guanidine derivatives with terminal heteroaromatic or terminal amine groups were used.

Claims

1. 1. A basic aqueous etching composition for treating a surface of a metal substrate, said composition comprising: (a) Formulas I and II 【Chemical 1】 [In the formula, X and Y are oxygen; R １ and R ２ is independently selected from the group consisting of hydrogen, alkyl compounds, amines, and nitrogen-containing heteroaromatic compounds; R １ and R ２ may be the same or different, provided that R １ must not be hydrogen, Additionally, in compounds having formula I, R １ must not be an alkyl compound, m is an integer from 1 to 4, n is an integer from 0 to 8, wherein m and n may be the same or different; and / or a salt thereof, (b) an oxidizing agent for oxidizing the metal on the surface of the metal to be treated; Including, The basic aqueous etching composition has a pH of 8 to 12.

2. 10. The basic aqueous etching composition of claim 1, wherein the functionalized urea and biuret derivatives and / or salts thereof are selected as compounds having Formula II and / or salts thereof.

3. R ２ The basic aqueous etching composition of claim 1 or 2, wherein is selected as hydrogen.

4. R １ and R ２ 4. The basic aqueous etching composition of claim 1, wherein at least one of the following is selected as an alkyl compound, which may be branched or unbranched.

5. R １ and R ２ At least one of ２ , N.H.R. ３ and N.R. ３ R ４ and selected from the group comprising: R ３ and R ４ are independently １ ~C １６ alkyl, 5- to 16-membered aryl and 5- to 16-membered heteroaryl, optionally OR ６ [where R ６ is hydrogen and C １ ~C ６ alkyl], NR ７ R ８ [where R ７ and R ８ are both independently hydrogen or C １ ~C ６ alkyl], and NH—CO—NH—(CH ２ ) ｏ -NR ９ R １０ wherein o is selected as an integer from 0 to 4, and R ９ and R １０ are both independently hydrogen or C １ ~C ６ 5. The basic aqueous etching composition of claim 1, wherein the alkyl group is selected from the group including those containing at least one substituent selected from the group including those containing alkyl.

6. R １ and R ２ 6. The basic aqueous etching composition of claim 1, wherein at least one of the following is selected as the nitrogen-containing heteroaromatic compound:

7. 7. The basic aqueous etching composition of claim 1, wherein n is an integer from 0 to 4.

8. The functionalized urea and biuret derivatives and / or salts thereof are selected as compounds and / or salts thereof having formula I, wherein m is 3 and n is 0 or 3; R １ Below: (a) NH ２ , N.H.R. ３ and N.R. ３ R ４ where R ３ and R ４ are independently １ ~C ６ alkyl, optionally NR ７ R ８ [where R ７ and R ８ are both independently hydrogen or C １ ~C ６ alkyl], and NH—CO—NH—(CH ２ ) ｏ -NR ９ R １０ wherein o is selected as an integer from 0 to 4, and R ９ and R １０ are both independently hydrogen or C １ ~C ６ alkyl; (b) 4- to 10-membered heteroaromatic compounds, optionally C １ ~C ６ containing at least one substituent selected as alkyl and R ２ Below: (a) hydrogen, (b) NH ２ , N.H.R. ３ and N.R. ３ R ４ where R ３ and R ４ are independently １ ~C ６ alkyl, optionally NR ７ R ８ [where R ７ and R ８ are both independently hydrogen or C １ ~C ６ alkyl], and NH—CO—NH—(CH ２ ) ｏ -NR ９ R １０ wherein o is selected as an integer from 0 to 4, and R ９ and R １０ are both independently hydrogen or C １ ~C ６ alkyl; (c) 4- to 10-membered heteroaromatic compounds, optionally C １ ~C ６ containing at least one substituent selected as alkyl, and (d) C １ ~C ６ Alkyl 8. The basic aqueous etching composition of claim 1, wherein the basic aqueous etching composition is selected from the group comprising:

9. 9. The basic aqueous etching composition of claim 1, wherein the compounds having formula I and II and / or salts thereof are present in the composition in a total concentration of 1 wt. % to 15 wt. %, based on the total weight of the composition.

10. A method for treating a metal substrate surface, comprising: (A) providing the metal substrate; (B) providing a basic aqueous etching composition for treating a metal substrate surface according to any one of claims 1 to 9; (C) contacting the metal substrate with the basic aqueous etching composition to etch the metal substrate surface; A method comprising:

11. The method comprises the further steps of: (D) after method step (C), recycling the basic aqueous etching composition, wherein step (D) comprises: (D1) increasing the temperature of the basic aqueous etching composition to obtain a basic aqueous etching composition having an increased temperature; (D2) filtering the elevated temperature basic aqueous etching composition to obtain a filtered basic aqueous etching composition; (D3) applying the filtered basic aqueous etching composition again to method step (C); The step 11. The method of claim 10, comprising:

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