Etching solution for titanium and copper, and manufacturing method and etching method for wiring board using same

Abstract

The present invention provides a practical technology that makes it possible to perform etching of titanium and copper by means of: an etching solution for titanium and copper; and a manufacturing method and an etching method for a wiring board using the same. The etching solution for titanium and copper is characterized by containing hydrogen peroxide, a strong alkali substance, and one or more compounds selected from the group consisting of a compound represented by general formula (I) (in formula (I), n indicates an integer of 1-4; when n is 1, A indicates –CH3, –CH2COOH, –C2H5, –C2H4–NH2, or –C2H4SO3H; and when n is 2-4, A indicates –H, –CH3, –CH2COOH, –C2H5, –C2H4OH, –C2H4–NH2, or –C2H4SO3H) and a compound represented by general formula (II) (in formula (II), m indicates an integer of 1-4; when m is 1, B indicates –CH2–CH2–NH2; when m is 2, B indicates –H, –CH2–CH2–NH2, or –CH2–, and when B is –CH2–, said B forms a cyclic structure with the other B; when m is 3, B indicates –H; and when m is 4, B indicates –H). Alternatively, the etching solution for titanium and copper is characterized by: containing diethanolamine and / or triethanolamine, hydrogen peroxide, and a strong alkali substance; having a pH of 12 or more; and containing no fluoride and ammonia and / or ammonium ions.

Description

Titanium and copper etching solution, and wiring board manufacturing method and etching method using the same

[0001] The present invention relates to an etching solution for titanium and copper, and a method for manufacturing a wiring board and an etching method using the same.

[0002] In recent years, the use of semi-additive processes has become more common in the manufacture of semiconductor package substrates due to the need for finer and denser wiring. While the seed layer in semi-additive processes has typically been formed using electroless copper plating, sputtering, which is advantageous for thinning and smoothing the seed layer, is being considered due to the demand for finer and denser wiring. To ensure adhesion strength, sputtering often forms a two-layer seed layer: a titanium layer deposited on the insulating substrate side and a copper layer deposited on top as a conductive layer. Subsequent processes, similar to those used in conventional semi-additive processes, involve photoresist exposure and development, copper plating to create a pattern, and then etching the seed layer to form wiring. However, unlike semi-additive processes that use electroless copper as a seed layer, sputtering creates a seed layer made of two different metals: titanium and copper. This requires a two-step etching process: first, using a copper etchant to remove the copper layer, and then using a titanium etchant to remove the titanium. Therefore, in order to reduce the number of steps, simultaneous etching solutions for titanium and copper have been developed (Patent Documents 1 to 3).

[0003] Furthermore, as etching solutions specifically for titanium, compositions containing hydrogen peroxide, a strong alkaline substance such as NaOH, and a complexing agent, and having a pH of 12 or higher, are disclosed in Patent Documents 4 and 5. Furthermore, Patent Documents 6 to 8 disclose weakly alkaline compositions containing hydrogen peroxide and ammonia, or hydrogen peroxide and a compound containing ammonium ions, and a basic compound, and having a pH of 7 to 11.

[0004] Retabulation No. 2011-093445 Publication JP 2017-031502 Publication Retabulation 2014-168037 Publication Patent No. 6061915 Publication U.S. Patent No. 4554050 Publication No. JP 08-013166 Publication Retamination 2018-181896 Publication JP 2005-320608 Publication

[0005] However, the etching solutions described in Patent Documents 1 to 3 contain fluoride, and in the case of acidic solutions, hydrofluoric acid gas (boiling point: approximately 20°C) is generated during operation, raising concerns that it may have adverse effects on the human body. Furthermore, etching solutions containing fluoride are corrosive to substrate materials such as silicon and glass, and therefore may not be usable.

[0006] Furthermore, the titanium-specific etching solutions described in Patent Documents 4 to 8 are all used in single-wafer processing, spin coaters, and the like in semiconductor manufacturing processes, but if copper ions are mixed in, the hydrogen peroxide contained therein decomposes, generating foaming and heat, making it practically impossible to etch both copper and titanium in a single process.

[0007] Therefore, an object of the present invention is to provide a practical technology that uses hydrogen peroxide but significantly suppresses decomposition of hydrogen peroxide during use, does not require the inclusion of fluoride, and is capable of etching titanium and copper in a single step.

[0008] As a result of intensive research to solve the above problems, the present inventors have discovered that by using a compound represented by a specific general formula in combination with hydrogen peroxide and a strong alkaline substance, it is possible to suppress the decomposition of hydrogen peroxide and stably etch titanium and copper, and have completed the present invention.

[0009] Furthermore, as a result of further intensive research aimed at solving the above-mentioned problems, the inventors discovered that by combining diethanolamine and / or triethanolamine with hydrogen peroxide and a strong alkaline substance, and further by not containing certain components at a specific pH, it is possible to suppress the decomposition of hydrogen peroxide and stably etch titanium and copper, thereby completing the present invention.

[0010] That is, the present invention is as follows: 1) A compound represented by the following general formula (I): (In formula (I), n is an integer of 1 to 4, and when n is 1, A is -CH ３ , -CH ２ COOH, -C ２ H ５ , -C ２ H ４ -NH ２ or -C ２ H ４ SO ３ When n is 2 to 4, A is -H or -CH ３ , -CH ２ COOH, -C ２ H ５ , -C ２ H ４ OH, -C ２ H ４ -NH ２ or -C ２ H ４ SO ３ H) and a compound represented by the following general formula (II): (In formula (II), m is an integer of 1 to 4, and when m is 1, B is —CH ２ -CH ２ -NH ２ When m is 2, B is —H, —CH ２ -CH ２ -NH ２ or -CH ２ - and B is -CH ２ (When m is -, B represents -H when m is 3, and B represents -H when m is 4), hydrogen peroxide, and a strong alkaline substance.

[0011] 2) The titanium and copper etching solution according to 1), wherein the compound represented by general formula (I) is N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine, 1,2-bis(hydroxyethylamino)ethane, or 2,2'-[iminobis(ethane-2,1-diimino)]bisethanol.

[0012] 3) The titanium and copper etching solution according to 1) or 2), wherein the compound represented by general formula (II) is triethylenetetramine, tris(2-aminoethyl)amine, tetraethylenepentamine or pentaethylenehexamine.

[0013] 4) The titanium and copper etching solution according to any one of 1) to 3), having a pH of 12 or higher.

[0014] 5) The titanium and copper etching solution according to any one of 1) to 4), which does not contain fluoride.

[0015] 6) The titanium and copper etching solution according to any one of 1) to 5), which does not contain ammonia and / or ammonium ions.

[0016] 7) The titanium and copper etching solution according to any one of 1) to 6), wherein the hydrogen peroxide content is 0.1 to 200 g / L.

[0017] 8) A titanium and copper etching solution, characterized in that it contains diethanolamine and / or triethanolamine, hydrogen peroxide, and a strong alkaline substance, has a pH of 12 or higher, and does not contain fluoride, ammonia, and / or ammonium ions.

[0018] 9) A method for etching titanium and copper, comprising etching titanium and copper with the titanium and copper etching solution according to any one of 1) to 8).

[0019] 10) A method for manufacturing a wiring board, comprising etching titanium and copper on a wiring board with the titanium and copper etching solution according to any one of 1) to 8).

[0020] 11) A titanium and copper etching solution containing hydrogen peroxide and a strong alkaline substance is added with a compound represented by the following general formula (I): (In formula (I), n is an integer of 1 to 4, and when n is 1, A is -CH ３ , -CH ２ COOH, -C ２ H ５ , -C ２ H ４ -NH ２ or -C２ H ４ SO ３ When n is 2 to 4, A is -H or -CH ３ , -CH ２ COOH, -C ２ H ５ , -C ２ H ４ OH, -C ２ H ４ -NH ２ or -C ２ H ４ SO ３ H) and a compound represented by the following general formula (II): (In formula (II), m is an integer of 1 to 4, and when m is 1, B is —CH ２ -CH ２ -NH ２ When m is 2, B is —H, —CH ２ -CH ２ -NH ２ or -CH ２ - and B is -CH ２ (When m is -, B represents -H when m is 3, and B represents -H when m is 4).

[0021] 12) A method for stabilizing a titanium and copper etching solution, comprising adding diethanolamine and / or triethanolamine to a titanium and copper etching solution that contains hydrogen peroxide and a strong alkaline substance, has a pH of 12 or higher, and is free of fluoride, ammonia, and / or ammonium ions.

[0022] The etching solution of the present invention is capable of etching titanium and copper, and also inhibits the decomposition of hydrogen peroxide, making it long-lasting and stable.

[0023] Therefore, the etching solution of the present invention is suitable for etching titanium and copper, particularly for the production of wiring boards.

[0024] 1 shows a cross-sectional view of a wiring substrate having a titanium and copper seed layer before and after etching during a semi-additive process, a cross-sectional view of an example of a wiring formation failure after etching of the wiring substrate, and cross-sectional SEM images (observed at 5000x magnification) of the wiring substrate before and after etching.

[0025] Among the titanium and copper etching solutions of the present invention (hereinafter referred to as "etching solution of the present invention"), a titanium and copper etching solution containing one or more compounds selected from the group consisting of compounds represented by the following general formula (I) and compounds represented by the following general formula (II), hydrogen peroxide, and a strong alkaline substance (hereinafter this etching solution will be referred to as "etching solution 1 of the present invention") will be described.

[0026] The compound represented by the general formula (I) is as follows: This compound has —CH ２ -CH ２ Since it has a specific number of OH bonds, it is suitable for the etching solution of the present invention. In formula (I), n is an integer of 1 to 4, and when n is 1, A is —CH ３ , -CH ２ COOH, -C ２ H ５ , -C ２ H ４ -NH ２ or -C ２ H ４ SO ３ When n is 2 to 4, A is -H or -CH ３ , -CH ２ COOH, -C ２ H ５ , -C ２ H ４ OH, -C ２ H ４ -NH ２ or -C ２ H ４ SO ３ H, preferably n is an integer of 1 to 4, and when n is 1, A is -CH ２ COOH, -C ２ H ４ -NH ２ When n is 2 to 4, A is -C ２ H ４ OH, -CH２ More preferably, n is an integer of 1 to 2, and when n is 1, A is —CH ２ COOH, -C ２ H ４ -NH ２ When n is 2, A is -C ２ H ４ OH, -CH ２ Indicates COOH.

[0027] Examples of the compound represented by formula (I) include N-methyldiethanolamine (CAS RN 105-59-9), N,N-di(2-hydroxyethyl)glycine (CAS RN 150-25-4), N-ethyldiethanolamine (CAS RN 139-87-7), N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (CAS RN 10191-18-1), 2,2'-((2-aminoethyl)azanediyl)diethanol (CAS RN 3197-06-6), N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine (CAS RN 140-07-8), 1,2-bis(hydroxyethylamino)ethane (CAS RN 4439-20-7), 2,2'-(ethane-1,2diylbis(methylazanediyl))diethanol (CAS RN 14037-83-3), 2,2-[1,2-ethanediylbis[(2-aminoethyl)imino]]bisethanol (CAS RN 177851-29-5), 2,2'-[iminobis(ethane-2,1-diimino)]bisethanol (CAS RN 4484-60-0), 2,2',2'',2'''-[[(2-hydroxyethyl)imino]bis(2,1-ethanediylnitrilo)]tetraethanol (CAS RN 59089-98-4), 3,6,9,12-tetraazatetradecane-1,14-diol (CAS RN No. 34238-21-6) are preferred, and N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine, 1,2-bis(hydroxyethylamino)ethane, and 2,2'-[iminobis(ethane-2,1-diimino)]bisethanol are particularly preferred.

[0028] The compound represented by the general formula (II) is as follows: This compound has —CH２ -CH ２ NH ２ Since a specific number of bonds are formed, it is suitable for the etching solution of the present invention. In formula (II), m is an integer of 1 to 4, and when m is 1, B is —CH ２ -CH ２ -NH ２ When m is 2, B is —H, —CH ２ -CH ２ -NH ２ or -CH ２ - and B is -CH ２ When m is -, it forms a cyclic structure with another B. When m is 3, B represents -H, and when m is 4, B represents -H. Preferably, m is an integer of 2 to 4, and when m is 2, B represents -H, -CH ２ -CH ２ -NH ２ or -CH ２ - and B is -CH ２ When m is -, it forms a cyclic structure with another B. When m is 3, B represents -H, and when m is 4, B represents -H. More preferably, m is an integer of 2 to 4, and B represents -H.

[0029] Preferred compounds represented by formula (II) include tris(2-aminoethyl)amine (CAS RN 4097-89-6), triethylenetetramine (CAS RN 112-24-3), tetraethylenepentamine (CAS RN 112-57-2), pentaethylenehexamine (CAS RN 4067-16-7), 2,2'-piperazine-1,4-diylbis(ethan-1-amine) (CAS RN 6531-38-0), and N,N,N',N'-tetrakis(2-aminoethyl)-1,2-ethanediamine (CAS RN 4097-90-9), with tetraethylenepentamine and pentaethylenehexamine being particularly preferred.

[0030] Among all the compounds represented by the above formula (I) or (II), N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine and tetraethylenepentamine are preferred.

[0031] The content of one or more compounds represented by general formula (I) and general formula (II) in the etching solution 1 of the present invention is not particularly limited, but may be, for example, 1 to 300 g / L, preferably 10 to 200 g / L, and more preferably 40 to 120 g / L. These compounds act as stabilizers for hydrogen peroxide and inhibit the decomposition of hydrogen peroxide. They particularly inhibit the decomposition of hydrogen peroxide in strongly alkaline etching solutions containing accumulated copper ions. These compounds also act as complexing agents for copper ions and inhibit copper etching. Without these compounds, the etching rate of copper is significantly faster than that of titanium. During processing of wiring substrates, the copper wiring width significantly decreases, the shape cannot be maintained, or the copper wiring falls off, making wiring formation impossible, before the titanium seed layer is completely removed.

[0032] The hydrogen peroxide content in the etching solution 1 of the present invention is not particularly limited, but may be, for example, 0.1 to 200 g / L, preferably 1 to 40 g / L, and more preferably 2 to 20 g / L. Hydrogen peroxide is a strong oxidizing agent and serves as an etching agent for titanium and copper. Without hydrogen peroxide, etching of titanium and copper hardly occurs. If the content is too low, the etching rate is slow, and the seed layer may not be removed within the target time. If the hydrogen peroxide content is too high, the amount of replenishment increases, which may result in poor process efficiency. The hydrogen peroxide content can be appropriately adjusted depending on the target process time. Those skilled in the art can make this adjustment without excessive use of conventional methods.

[0033] The strong alkaline substance used in the etching solution 1 of the present invention is not particularly limited, but examples thereof include sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide (TMAH), and tetraethylammonium hydroxide (TEAH). The content of the strong alkaline substance in the etching solution 1 of the present invention is not particularly limited, but is, for example, 20 to 500 g / L, preferably 90 to 300 g / L, and more preferably 150 to 250 g / L. The strong alkaline substance is an etching agent for titanium and copper. If the content of the strong alkaline substance is too low, the etching rate may be insufficient, while if the content is too high, crystallization may occur. To prevent crystallization, it is necessary to adjust the content of the strong alkaline substance and the content of other components together. Those skilled in the art can make this adjustment without excessive use of conventional methods.

[0034] The etching solution 1 of the present invention is strongly alkaline, and the pH is preferably at least 12, more preferably at least 13. The pH of the etching solution 1 of the present invention may be adjusted by the amount of the strong alkaline substance added.

[0035] Furthermore, the etching solution 1 of the present invention may contain additives such as a copper etching accelerator, a hydrogen peroxide stabilizer other than the above compounds, and rust-preventive components such as inhibitors.

[0036] Examples of copper etching accelerators include amines such as ethylenediamine and 1,3-propanediamine.

[0037] Examples of hydrogen peroxide stabilizers other than the above compounds include phenolsulfonic acid and its salts, and alcohols such as 1-propanol.

[0038] Examples of rust-preventive components such as inhibitors include mercaptobenzothiazole, tolyltriazole, benzotriazole, 3-aminotriazole, and 5-amino-1H-tetrazole.

[0039] The content of the additive in the etching solution 1 of the present invention is not particularly limited, and it may be contained in a known amount.

[0040] The performance of the etching solution 1 of the present invention is not affected even if it contains copper ions, titanium ions, etc. that are generated during etching.

[0041] Furthermore, the etching solution 1 of the present invention may not contain fluorides used in conventional etching solutions for titanium and copper, and preferably does not contain fluorides. In this specification, "does not contain" means that the substance is not added, or that the substance is not contained except as unavoidable impurities.

[0042] Furthermore, the etching solution 1 of the present invention may not contain ammonia and / or ammonium ions used in conventional etching solutions for titanium and copper, and preferably does not contain ammonia and / or ammonium ions. The ammonium ions referred to here are NH ４ ＋ This refers to:

[0043] The etching solution 1 of the present invention preferably contains the following components, and preferably consists of the following components: 40 to 120 g / L of one or more compounds selected from the group consisting of general formulas (I) and (II), 2 to 10 g / L of hydrogen peroxide, 120 to 200 g / L of sodium hydroxide, an appropriate amount of water, pH 13 or higher, and optionally contains the following: 0 to 6 g / L of ethylenediamine

[0044] The method for preparing the etching solution 1 of the present invention is not particularly limited, and it can be prepared, for example, by mixing the above components in water.

[0045] As described above, titanium and copper etching solutions containing hydrogen peroxide and a strong alkaline substance can be stabilized by adding one or more compounds selected from the group consisting of the compounds represented by the general formula (I) and the compounds represented by the general formula (II). Here, "stabilization" refers to the ability to inhibit decomposition of hydrogen peroxide even when copper accumulates during etching. Decomposition of hydrogen peroxide is inhibited when the residual hydrogen peroxide rate after 30 minutes is greater than 1%, preferably 50% or greater, of the initial content when 2 g / L of copper ions accumulate in the etching solution. For example, when the stabilizer in the above composition is replaced with EDTA, a known etching solution stabilizer, the residual hydrogen peroxide rate after 30 minutes at a copper concentration of 2 g / L is less than 1%, indicating that EDTA has no inhibitory effect. Similarly, when the above composition is used, the residual hydrogen peroxide rate after 30 minutes at a copper concentration of 2 g / L is greater than 1%, indicating that decomposition is inhibited.

[0046] The hydrogen peroxide content can be measured by titration with cerium (IV) ions. 1 mL of the etching solution is placed in a 300 mL conical beaker, 50 mL of pure water is added, 5 mL of sulfuric acid (50 wt%) and 3 drops of ferroin indicator are added, and the cerium (IV) (Ce ４＋ The titration is performed with a cerium (IV) standard solution (0.1 mol / L). The endpoint is when the color of the solution changes from orange to colorless or pale blue, and the titration volume of the cerium (IV) standard solution at this point is V (mL). The hydrogen peroxide content is calculated using the following formula: (Equation 1) Hydrogen peroxide content (g / L) = V (mL) x 1.701 x factor of cerium standard solution

[0047] Among the etching solutions of the present invention, a titanium and copper etching solution containing diethanolamine (CAS RN 111-42-2) and / or triethanolamine (CAS RN 102-71-6), hydrogen peroxide, and a strong alkaline substance, having a pH of 12 or higher, and not containing fluoride, ammonia, and / or ammonium ions (hereinafter, this etching solution will be referred to as "etching solution 2 of the present invention") will be described.

[0048] Of the above diethanolamine and triethanolamine, triethanolamine is preferred.

[0049] The content of diethanolamine and / or triethanolamine, the content of hydrogen peroxide, and the type and content of the strong alkaline substance in the etching solution 2 of the present invention are the same as those in the etching solution 1 of the present invention.

[0050] The etching solution 2 of the present invention does not contain fluoride, ammonia and / or ammonium ions. The ammonium ions referred to here are NH ４ ＋ This refers to:

[0051] The pH of the etching solution 2 of the present invention is at least 12, and more preferably at least 13. The pH of the etching solution 2 of the present invention may be adjusted by the amount of strong alkaline substance added, as in the case of the etching solution 1 of the present invention.

[0052] The additives that may be contained in the etching solution 2 of the present invention and the contents thereof are the same as those in the etching solution 1 of the present invention.

[0053] As with etching solution 1 of the present invention, the performance of etching solution 2 of the present invention is not affected even if it contains copper ions, titanium ions, etc. that are generated during etching.

[0054] The etching solution 2 of the present invention preferably contains the following components, and preferably consists of the following components: Diethanolamine and / or triethanolamine 40 to 120 g / L Hydrogen peroxide 2 to 10 g / L Sodium hydroxide 120 to 200 g / L Water Appropriate amount pH 13 or higher If necessary, the following components may be contained: Ethylenediamine 0 to 6 g / L

[0055] The method for preparing the etching solution 2 of the present invention is not particularly limited, and it can be prepared, for example, by mixing the above components in water.

[0056] As described above, the titanium and copper etching solution can be stabilized by adding the above-mentioned diethanolamine and / or triethanolamine to a titanium and copper etching solution that contains hydrogen peroxide and a strong alkaline substance, has a pH of 12 or higher, and does not contain fluoride, ammonia, and / or ammonium ions. The definition of "stabilization" and the evaluation of whether decomposition of hydrogen peroxide is suppressed are the same as those for etching solution 1 of the present invention.

[0057] The etching solution 1 of the present invention and the etching solution 2 of the present invention have the same effect, and therefore they may be used in combination.

[0058] The etching solution of the present invention described above (including both etching solution 1 of the present invention and etching solution 2 of the present invention) can etch titanium and copper. The etching solution of the present invention can also etch titanium-containing alloys, titanium oxides, etc., as well as copper-containing alloys, copper oxides, etc., but is preferably titanium and copper.

[0059] The object to be etched with the etching solution of the present invention may contain titanium and copper. The titanium and copper may be in the form of layers. It goes without saying that the etching solution of the present invention can also be applied to an object containing only titanium or only copper.

[0060] Examples of such objects include thin films containing titanium and copper layers, substrates on which a copper pattern is formed using photoresist on a multilayer thin film containing titanium and copper layers, and substrates having two or more layers in which titanium and copper layers are appropriately combined. The insulating material of the substrate is not particularly limited, but examples include epoxy, polyimide, silicon, glass, and the like used in semi-additive processes. These materials allow preferential etching of titanium and copper.

[0061] Examples of substrates that can be suitably etched with the etching solution of the present invention include motherboards, semiconductor package substrates, interposers, and RDLs (redistribution layers).

[0062] The conditions for etching titanium and copper with the etching solution of the present invention are not particularly limited, but for example, the etching solution may be heated to 20 to 80° C., preferably 25 to 35° C., and the target may be immersed in the etching solution or the etching solution may be sprayed (atomized) onto the target. The etching time may be appropriately set depending on the target.

[0063] The etching solution of the present invention is capable of etching titanium and copper while suppressing the decomposition of hydrogen peroxide, resulting in a long life and stability. Whether or not hydrogen peroxide decomposition is suppressed means that the residual hydrogen peroxide rate is higher than 1%, preferably 50% or higher, as determined by the method described in the Examples. Furthermore, the ability of the etching solution of the present invention to etch titanium and copper means that titanium and copper can be removed within 10 minutes, preferably within 5 minutes, as determined by the method described in the Examples.

[0064] The etching rates of titanium and copper with the etching solution of the present invention are not particularly limited, but for example, in the case of an etching solution containing hydrogen peroxide, sodium hydroxide, and N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine and having a pH of 13.5, the etching rate for titanium is 2 to 300 nm / min, preferably 40 to 150 nm / min, and the etching rate for copper is 10 to 2000 nm / min, preferably 40 to 200 nm / min.

[0065] Furthermore, a wiring board can be manufactured by etching titanium and copper on the wiring board with the etching solution of the present invention. For example, a photoresist pattern is formed on a multilayer thin film containing a sputtered titanium layer and a sputtered copper layer as a seed layer of the wiring board, a copper pattern is formed by copper plating, and then the resist is peeled off. Thereafter, the seed layer (titanium layer and copper layer) between the copper patterns is etched away by immersion in the etching solution of the present invention or spray treatment (atomization), thereby manufacturing a wiring board.

[0066] FIG. 1 is an explanatory diagram of the seed layer etching step in a semi-additive process using the etching solution of the present invention. Note that this diagram only schematically illustrates the cross-sectional structure necessary for explaining the present invention. Before the etching process in FIG. 1(a), a seed layer 20 (sputtered titanium layer 22 and sputtered copper layer 21) is first formed on an insulating material 10 by sputtering to form wiring. A photoresist (not shown) is then applied to the seed layer, and after exposure and development, a copper wiring pattern 30 is formed by electrolytic copper plating. The photoresist is then peeled off. The seed layer 20 between the copper patterns is then removed by contacting the etching solution of the present invention. The cross-sectional structure after this etching process is as shown in FIG. 1(b) after the etching process. This FIG. 1 is also used in the examples.

[0067] Figure 2 is an explanatory diagram showing an example of a failed wiring formation by etching. In Figure 2(a), the etching rate of copper is faster than that of titanium, so the sputtered copper layer 21 of the seed layer 20 is completely etched between the wiring, but the sputtered titanium layer 22 has not yet been completely removed, resulting in the copper wiring pattern 30 becoming thinner and the wiring falling off. On the other hand, in Figure 2(b), the etching rate of titanium is slow, so the sputtered copper layer 21 of the seed layer 20 between the copper patterns is completely removed within the specified target time, but the sputtered titanium layer 22 has not yet been completely removed, resulting in the wiring width of the copper pattern 30 becoming thinner due to the long etching time. Figure 2 is also used in the examples.

[0068] Figure 3 shows cross-sectional SEM images of a wiring substrate before and after etching, showing a successful example of wiring formation by etching. The seed layer between the copper wiring has been removed without any residue. The shape of the copper wiring is also maintained, with no undercuts. Figure 3 is also used in the examples.

[0069] The etching solution of the present invention can be used not only to etch titanium and copper in the semi-additive process described above to produce wiring boards, but also in other processes that require etching of titanium and copper. Examples of such processes include the manufacturing process of RDL for semiconductor wafers. This process also requires etching of titanium and copper.

[0070] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0071] Test Example 1: Hydrogen Peroxide Stability Test: 100 mL of etching solutions were prepared by adding 180 g / L of sodium hydroxide, 8 g / L of hydrogen peroxide, and 40 to 120 g / L of a compound corresponding to general formula (I) shown in Table 1, a compound corresponding to general formula (II) shown in Table 2, or a compound not corresponding to either of the above shown in Table 3 (a compound commonly used in etching). Etching solutions without any of the compounds were also prepared in the same manner. The pH of these etching solutions was 12 or higher. A copper plate (4 × 4 cm) was placed in each of these etching solutions, and copper was dissolved at 30°C with stirring to a copper concentration of 2 g / L. The required time varied depending on the composition, but was within 2 hours in all cases.

[0072] The concentration of hydrogen peroxide in the etching solution in which copper was dissolved so that the copper concentration was 2 g / L was measured by the above-mentioned cerium (IV) ion titration method. Based on this measurement, the consumed amount of hydrogen peroxide was replenished so that the concentration of hydrogen peroxide returned to the initial value of 8 g / L. The etching solution after replenishment was left at 30°C for 30 minutes, and then the concentration of hydrogen peroxide C was measured again. ３０ｍ The residual hydrogen peroxide rate (after 30 minutes) was calculated according to the following formula and shown in Tables 1 to 3. (Equation 2) Hydrogen peroxide residual rate (after 30 minutes) = C ３０ｍ ×100% / 8

[0073] <Calculation Example> After dissolving copper so that the copper concentration becomes 2 g / L, if the measured hydrogen peroxide concentration is 6 g / L, hydrogen peroxide is replenished by 2 g / L to make it 8 g / L after replenishment. After leaving the replenished etching solution at 30°C for 30 minutes, the measured hydrogen peroxide concentration is 7.5 g / L (C ３０ｍIn this case, the residual hydrogen peroxide rate (after 30 minutes) was calculated using the above formula and was found to be 94%.

[0074]

[0075]

[0076]

[0077] From the above results, it was found that the etching solution containing the compound represented by general formula (I) or general formula (II) suppresses the decomposition of hydrogen peroxide in the presence of copper (under the same conditions as after etching).

[0078] On the other hand, it was found that the etching solutions containing 180 g / L of sodium hydroxide and 8 g / L of hydrogen peroxide, to which 40 to 120 g / L of the commonly used compounds shown in Table 3 had been added, or etching solutions containing no compounds, were unable to suppress the decomposition of hydrogen peroxide.

[0079] Test Example 2 Hydrogen Peroxide Stabilization Test: 180 g / L of sodium hydroxide, 8 g / L of hydrogen peroxide, and the compounds shown in Table 4 were added to prepare 100 mL of etching solutions. The pH of these etching solutions was 12 or higher. The residual hydrogen peroxide rate (after 30 minutes) of these etching solutions was calculated in the same manner as in Test Example 1, and the results are shown in Table 4.

[0080]

[0081] From the above results, it was found that an etching solution containing diethanolamine or triethanolamine suppresses the decomposition of hydrogen peroxide in the presence of copper (under the same conditions as after etching).

[0082] Test Example 3 (1) Test 1: Measurement of etching rates of titanium and copper: As shown in Table 5 below, 100 mL of each etching solution was prepared with the excess water. A titanium plate (4 x 4 cm) and a copper plate (4 x 4 cm) were immersed for 3 minutes in the etching solutions of Examples 1 to 10 at 30°C, or in the etching solutions of Examples 11 and 12 at 70°C, while stirring, and the etching rates (ER) were measured by the weight difference method. The density of copper was 8.93 g / cm. ３The density of titanium is 4.51 g / cm ３ The measurement results are shown in Table 6. The same test was conducted on Comparative Examples 1 to 7, and the results are also shown in Table 6.

[0083] (2) Test 2: Etching Treatment of Wiring Board Seed Layer: Using each of the etching solutions described in Test 1 above, a seed layer etching treatment was performed on a semi-additive process wiring board as shown in Figure 1(a). The insulating material 10 in Figure 1 was a build-up film (ABF GX-T31: manufactured by Ajinomoto Fine-Techno Co., Ltd.), and within the seed layer 20, the sputtered titanium layer 22 was 80 nm thick and the sputtered copper layer 21 was 200 nm thick. The substrate size was 2 x 2 cm, the copper wiring height was 5 μm, and the wiring specifications were L / S = 5 / 5 μm. The etching treatment was performed at 30°C with stirring for the just-etching time (the time required to remove the seed layer between the wiring) for each composition. The just-etching time was calculated based on the etching rate in Test 1 and was always within 8 minutes. The wiring formability after treatment was evaluated according to the following criteria. The evaluation results are shown in Table 6. The same evaluation was performed on Comparative Examples 1 to 7, and the results are also shown in Table 6.

[0084] (3) Test 3: Performance Confirmation After Copper Accumulation in Etching Solution: Copper was further dissolved in the solution of Test 2 above so that the copper concentration was 2 g / L, and the amount of decomposed hydrogen peroxide was replenished to prepare an etching solution after copper accumulation (2 g / L). Using this etching solution after copper accumulation, the etching rates of titanium and copper were measured in the same manner as in Test 1, and an etching process for the wiring substrate seed layer was performed in the same manner as in Test 2, and wiring formability was evaluated. The results of measuring the solution performance after copper accumulation are also shown in Table 6. The same test was conducted on Comparative Examples 1 to 7, and the results are also shown in Table 6.

[0085] <Evaluation criteria for wiring substrate wiring formability> (Evaluation) (Contents) ○: Good wiring formability. As shown in Figure 3, when the cross section of the substrate was observed with an SEM after processing, the seed layer between the copper wiring was removed without residue, the shape of the copper wiring was maintained, and there was no undercut. ×: Poor wiring formability. As shown in Figure 2, phenomena such as (a) wiring falling off and (b) titanium layer remaining occurred, and the shape of the copper wiring could not be maintained.

[0086]

[0087]

[0088] From the above results, it was found that etching solutions containing one or more compounds selected from the compounds represented by the above general formula (I) and general formula (II), or diethanolamine and triethanolamine, can etch copper and titanium, and have good wiring formation properties on wiring boards. It was also found that etching solutions containing a combination of the compounds represented by the above general formula (I) and general formula (II) and triethanolamine have the same effect as those containing the compounds alone. Furthermore, even after copper accumulation through continuous processing, the etching rates of copper and titanium and the wiring formation properties on wiring boards remained unchanged and were good, similar to the initial performance.

[0089] On the other hand, it was found that the etching solution not containing the compound of Comparative Example 1 and the etching solutions containing the compounds used in Comparative Examples 2 to 7 were unable to form wiring even immediately after preparation, or were only able to form wiring immediately after preparation. In particular, it was found that etching after copper accumulation due to continuous processing was not possible, and the etching rate was significantly reduced, making it impossible to form wiring.

[0090] Example 13: Manufacturing of Wiring Board: (1) Seed Layer Formation: A titanium layer (80 nm, sputtering time: 9 minutes 20 seconds) and a copper layer (200 nm, sputtering time: 8 minutes 50 seconds) were formed in this order on a substrate insulating material (ABF GX-T31, manufactured by Ajinomoto Fine-Techno Co., Ltd.) by sputtering. (2) Photolithography: A liquid resist (TMMR P-W1000T, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to the substrate obtained in (1) using a spin coater to a thickness of 5 μm. The resist was then baked at 110°C for 90 seconds. Next, stepper exposure (i-line stepper NSR-2005i9, manufactured by Nikon) was performed, followed by development using a developing solution (NMD-3 2.38%, manufactured by Tokyo Ohka Kogyo Co., Ltd.). (3) Electrolytic Copper Sulfate Plating: The substrate obtained in (2) was electrolytically plated with copper sulfate using the steps listed in Table 7 below.

[0091]

[0092] (4) Resist Removal The substrate obtained in (3) was immersed in a resist remover (ST-120: manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 40°C for 10 minutes to remove the resist, followed by washing with pure water and drying. (5) Seed Layer Etching The substrate obtained in (4) was brought into contact (immersed or sprayed) with the etching solution of Examples 1 to 12 to remove the seed layer, thereby producing a wiring substrate.

[0093] In the wiring board manufactured in this manner, the seed layer between the copper wirings was removed without any residue, the shape of the copper wiring was maintained, and there was no undercut.

[0094] The etching solution of the present invention can be used for etching titanium and copper, particularly in the manufacture of substrates.

[0095] 10...insulating material 20...seed layer 21...sputtered copper layer 22...sputtered titanium layer 30...copper wiring pattern

Claims

1. The following general formula (I) (In formula (I), n is an integer from 1 to 4. When n = 1, A is -CH ３ , -CH ２ COOH, -C ２ H ５ , -C ２ H ４ -NH ２ or -C ２ H ４ SO ３ H. When n is from 2 to 4, A is -H, -CH ３ , -CH ２ COOH, -C ２ H ５ , -C ２ H ４ OH, -C ２ H ４ -NH ２ or -C ２ H ４ SO ３ H.) A compound represented by and the following general formula (II) (In formula (II), m is an integer from 1 to 4. When m = 1, B is -CH ２ -CH ２ -NH ２ . When m = 2, B is -H, -CH ２ -CH ２ -NH ２ or -CH ２ -. And when B is -CH ２ -, it forms a cyclic structure with another B. When m = 3, B represents -H, and when m = 4, B represents -H.) An etching solution for titanium and copper, characterized by containing one or more selected from the group consisting of the compounds represented by, hydrogen peroxide, and a strong alkaline substance.

2. The etching solution for titanium and copper according to claim 1, wherein the compound represented by the general formula (I) is N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine, 1,2-bis(hydroxyethylamino)ethane, or 2,2'-[iminobis(ethane-2,1-diimino)]bisethanol.

3. The etching solution for titanium and copper according to claim 1, wherein the compound represented by the general formula (II) is triethylenetetramine, tris(2-aminoethyl)amine, tetraethylenepentamine, or pentaethylenehexamine.

4. The etching solution for titanium and copper according to claim 1, wherein the pH is 12 or more.

5. The etching solution for titanium and copper according to claim 1, which does not contain fluoride.

6. The etching solution for titanium and copper according to claim 1, which does not contain ammonia and / or ammonium ions.

7. The etching solution for titanium and copper according to claim 1, wherein the hydrogen peroxide content is 0.1 to 200 g / L.

8. An etching solution for titanium and copper, which contains diethanolamine and / or triethanolamine, hydrogen peroxide, and a strong alkali substance, has a pH of 12 or more, and does not contain fluoride, ammonia, and / or ammonium ions.

9. An etching method for titanium and copper, characterized by etching titanium and copper with the etching solution for titanium and copper according to any one of claims 1 to 8.

10. A method for manufacturing a wiring board, characterized by etching titanium and copper on the wiring board with the etching solution for titanium and copper according to any one of claims 1 to 8.

11. In an etching solution for titanium and copper containing hydrogen peroxide and a strong alkaline substance, a compound represented by the following general formula (I) (In formula (I), n is an integer from 1 to 4. When n = 1, A is -CH ３ , -CH ２ COOH, -C ２ H ５ , -C ２ H ４ -NH ２ Or -C ２ H ４ SO ３ H. When n = 2 - 4, A is -H, -CH ３ , -CH ２ COOH, -C ２ H ５ , -C ２ H ４ OH, -C ２ H ４ -NH ２ Or -C ２ H ４ SO ３ H) and a compound represented by the following general formula (II) (In formula (II), m is an integer from 1 to 4. When m = 1, B is -CH ２ -CH ２ -NH ２ . When m = 2, B is -H, -CH ２ -CH ２ -NH ２ Or -CH ２ -. And when B is -CH ２ -, it forms a cyclic structure with another B. When m = 3, B is -H. When m = 4, B is -H). A method for stabilizing an etching solution for titanium and copper, characterized by adding one or more selected from the group consisting of these compounds.

12. A method for stabilizing an etching solution for titanium and copper, characterized by adding diethanolamine and / or triethanolamine to an etching solution for titanium and copper, which contains hydrogen peroxide and a strong alkali substance, has a pH of 12 or more, and does not contain fluoride, ammonia, and / or ammonium ions.

Images