JP6516214B2 - Etching solution for multilayer film, etching solution and etching method - Google Patents

Description

  The present invention relates to a multilayer film etching solution, an etching solution, and a method for etching a multilayer film of a copper layer and a molybdenum layer used for wiring of a flat panel display such as liquid crystal and organic EL.

  Aluminum has been used as a wiring material for TFTs (Thin Film Transistors) of flat panel displays (FPDs) such as liquid crystal and organic EL (Electro-Luminescence). In recent years, large-screen, high-definition FPDs have become widespread, and wiring materials to be used have been required to have lower resistance than aluminum. Therefore, copper having a resistance lower than that of aluminum has recently been used as a wiring material.

  When copper is used as a wiring material, two problems occur: adhesion to the substrate and diffusion to the semiconductor substrate. That is, in the case of using for gate wiring, adhesion may not be sufficient between substrates such as glass even when using a sputtering method that is considered to have a relatively high impact energy to the substrate. In addition, in the case of using in source / drain wiring, there is a problem that the adhered copper is diffused to the underlying silicon, and the electrical design value of the semiconductor is changed.

  In order to solve this problem, a multilayer structure in which a molybdenum layer is first formed on a substrate or a semiconductor substrate and a copper layer is formed on the molybdenum layer is currently employed.

The wiring of FPD is formed by wet etching a multilayer film formed by sputtering. This is because a large area can be formed at once, which makes it possible to shorten the process. Here, the following points are considered important for the wet etching of the wiring.
(1) High processing accuracy and uniformity.
(2) The wiring cross section after processing is a forward taper of a predetermined angle.
(3) The etching performance is unlikely to be degraded (the bath life is long) by the copper ion being contained in the etching solution.
(4) There should be little generation of precipitates.

  The first item, that the processing accuracy is high and uniform, is an item which is essential for processing not only wet etching but also a minute region. The shape of the cross section of the wiring, which is the second item, is a shape necessary to form reliable wiring when collectively forming a large area FPD wiring. This is because if the etched edge portion of the multilayer film of the copper layer and the molybdenum layer is formed with a forward taper of 30 to 60 degrees from the substrate, an etching failure will temporarily occur, and the etching rates of copper and molybdenum Even if the balance is different, it is possible to secure a margin by which product quality can be secured.

  The third item is the problem of the life of the etching solution itself. A large amount of etchant is required to etch large area substrates. These etchants are also recycled from the viewpoint of cost. If the period (life) in which the etching performance can be maintained is as long as possible, the cost is reduced.

  The fourth item relates not only to the problem of maintaining the etching apparatus but also to the problem of product quality. If a deposit is generated by the etching, it will cause a pipe clogging of the etching apparatus or clog a hole of a shower nozzle for sprinkling an etching solution. These phenomena cause the operation of the etching apparatus to stop, leading to an increase in cost. In addition, when the deposit adheres on the product through the etching solution, it causes a short circuit or a break, which directly affects the quality of the product.

  As an etching solution for a multilayer film of a copper layer and a molybdenum layer, there is a report on an etching solution containing hydrogen peroxide and at least one selected from neutral salts and organic acids (Patent Document 1).

  Further, hydrogen peroxide, an organic acid, a phosphate, a water-soluble cyclic amine compound as a first additive, and a water-soluble compound containing one of an amino group and a carboxyl group as a second additive An etching solution of a copper-molybdenum film containing a predetermined amount of each of a fluorine compound and deionized water has been reported (Patent Document 2).

  In addition, there is a report of an etching solution for molybdenum / copper / molybdenum nitride multiple film wiring containing hydrogen peroxide, an organic acid, a triazole compound, a fluorine compound, and ultrapure water (Patent Document 3).

  Furthermore, (A) hydrogen peroxide, (B) a fluorine-free inorganic acid, (C) succinic acid, glycolic acid, lactic acid, malonic acid and at least one organic acid selected from malic acid, (D) carbon And an amine compound having two or more amino groups and hydroxyl groups so that the total number of groups is two or more, (E) 5-amino-1H-tetrazole, and (F) hydrogen peroxide stabilizer. An etchant for a multilayer thin film comprising a copper layer and a molybdenum layer having a pH of 2.5 to 5 has been reported (Patent Document 4).

Unexamined-Japanese-Patent No. 2002-302780 (patent 4822927) Unexamined-Japanese-Patent No. 2004-193620 (patent 4448322) Unexamined-Japanese-Patent No. 2007-005790 (patent 5111790) Patent No. 5051323

  Patent Document 1 discloses that in the case of a mixed solution of hydrogen peroxide and an organic acid, copper and molybdenum can be simultaneously etched by adjusting the ratio of hydrogen peroxide, and a specific etching solution is disclosed. No composition is disclosed at all.

  In Patent Documents 2 and 3, a fluorine compound is used in the composition. Therefore, not only there is a problem that the glass substrate and the silicon substrate are also etched, but there is also a problem that the environmental load is increased when the etching solution is discarded.

  Patent Document 4 discusses in detail the etching of a multilayer film of a copper layer and a molybdenum layer. However, the composition of the etching solution of Patent Document 4 has a problem that a large amount of precipitates are generated in the etching solution.

  In addition, when a phosphorus compound or a fluorine compound is used as a component of the etching solution, the performance as the etching solution can be easily obtained, but the burden on the environment becomes large at the time of disposal.

  Hydrogen peroxide also decomposes itself. If left to stand, the proportion of hydrogen peroxide decreases and the etching rate changes significantly. Therefore, the decomposition of hydrogen peroxide must be suppressed to a certain extent.

  The present invention has been conceived in view of the above problems, and an etching solution composition of a multilayer film including a copper layer and a molybdenum layer satisfying the points considered to be important for the wet etching of the wiring described in [Background Art]. To provide In particular, the present invention provides an etching solution which does not generate precipitates in the etching solution and does not increase the load on the environment at the time of disposal, and a concentration solution thereof and an etching method.

More specifically, the etching solution for a multilayer film containing a copper layer and a molybdenum layer according to the present invention,
With hydrogen peroxide,
Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
Look containing hydrogen peroxide decomposition inhibitor, wherein the azole compound, a phosphorus compound, the fluorine-free compound.

In addition, the etching solution according to the present invention can be configured in the form of a concentrated solution so as not to be bulky during storage or transfer. More specifically, the etching solution for a multilayer film comprising a copper layer and a molybdenum layer according to the present invention,
Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
Hydrogen peroxide decomposition inhibitor,
Water only contains, characterized azole compound, a phosphorus compound, the fluorine-free compound.

Further, the etching method of a multilayer film including a copper layer and a molybdenum layer according to the present invention is
Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
Look containing hydrogen peroxide decomposition inhibitor and water, and the azole compound, a phosphorus compound, a step of preparing the multi-layer film for an etching solution formulated an etching concentrate and water and hydrogen peroxide containing no fluorine compound,
It is characterized in that it includes a step of bringing the etching solution for multilayer film into contact with the substrate to be treated.

  In the etching solution according to the present invention, the cross-sectional shape of the etched wiring becomes forward tapered, and the shape is maintained even if it is over-etched. Moreover, since it is a structure which does not contain the azole compound which produces a precipitate when used with hydrogen peroxide, a precipitate does not generate | occur | produce in an etching liquid and problems, such as piping clogging and the hole clogging of a shower nozzle, generate | occur | produce. Therefore, there is no need to stop the operation of the etching apparatus due to the generation of precipitates, and stable production is possible.

  Further, since the etching concentrate according to the present invention does not contain hydrogen peroxide and a predetermined amount of water from the above-mentioned etching solution, it can be stored or transported without being bulky and causing almost no change over time. Further, since the etching concentrate and the hydrogen peroxide can be handled separately, it is possible to easily adjust the concentration of the etching solution whose component concentration has been changed by use.

  In the etching method according to the present invention, since the etching concentrate and the hydrogen peroxide solution are mixed to prepare the etching solution and the substrate is brought into contact with the substrate to be treated, the etching solution having a stable composition can be prepared at any time. The cross section of the formed wiring has a forward taper, and even if it is over-etched, the taper angle can be etched while maintaining a suitable range of angles.

  In addition, since the etching solution according to the present invention does not contain a substance such as a phosphorus compound, a chlorine compound or a fluorine compound, there is an advantage that the load on the environment is light when discarded.

It is a conceptual diagram showing the cross section of the wiring formed by the etching.

  The etching solution according to the present invention will be described below. The following description shows one embodiment of the etching solution according to the present invention, and the following embodiments and examples may be modified without departing from the spirit of the present invention. The etching solution according to the present invention is characterized in that precipitates are not generated in the etching solution. As shown in the examples described later, it was strongly suggested that the cause of the precipitate is a reaction product of an azole compound and hydrogen peroxide. Therefore, the etching solution according to the present invention does not contain an azole compound.

  In addition, phosphorus compounds, fluorine compounds and chlorine compounds are also not included to reduce the environmental burden. However, it may be included if the etching performance and product quality are not affected or the environmental load at the time of disposal is below the standard defined in each country. Also, such amount may be interpreted as not including.

<Hydrogen peroxide>
In the etching of copper, copper is oxidized to form copper oxide (CuO), which is dissolved by an inorganic acid. In addition, the etching of molybdenum is oxidized to molybdenum oxide (MoO ₃ ), which dissolves in water. Hydrogen peroxide is used as an oxidizing agent to oxidize copper and molybdenum. The hydrogen peroxide is preferably 3.50% by mass or more and 5.80% by mass or less of the total amount of the etching solution. Hydrogen peroxide is also referred to as "peroxide".

<Inorganic acid>
Inorganic acids are used to dissolve oxidized copper. Phosphorus compounds and fluorine compounds are not used in order not to affect the substrate materials such as glass and silicon, and to reduce the environmental burden when discarding the etching solution. Also, hydrochloric acid is not used. Nitric acid and sulfuric acid can be suitably used. The inorganic acid is contained in the range of 0.01% by mass or more and 2.00% by mass or less, preferably 0.02% by mass or more and 1.50% by mass or less based on the total amount of the etching solution.

<Organic acid>
The organic acid component mainly serves to adjust the taper angle of the cross section of the etched wiring. In addition, it is considered that it also has a function of suppressing the decomposition of hydrogen peroxide to some extent. As the organic acid component, a combination of an acidic organic acid and a neutral organic acid is used. Moreover, you may combine both an acidic organic acid and a neutral organic acid.

  As an organic acid which can be used, a C1-C18 amino acid other than a C1-C18 aliphatic carboxylic acid, a C6-C10 aromatic carboxylic acid, etc. are mentioned preferably.

  Examples of aliphatic carboxylic acids having 1 to 18 carbon atoms include formic acid, acetic acid, propionic acid, lactic acid, glycolic acid, glycolic acid, diglycolic acid, pyruvic acid, malonic acid, butyric acid, hydroxybutyric acid, tartaric acid, succinic acid, malic acid and maleic acid , Fumaric acid, valeric acid, glutaric acid, itaconic acid, adipic acid, caproic acid, adipic acid, citric acid, propanetricarboxylic acid, trans-aconitic acid, enanthate, caprylic acid, lauric acid, myristic acid, palmitic acid, stearin Preferred are acid, oleic acid, linoleic acid, linolenic acid and the like.

  Preferred examples of the aromatic carboxylic acid having 6 to 10 carbon atoms include benzoic acid, salicylic acid, mandelic acid, phthalic acid, isophthalic acid and terephthalic acid.

  Further, as the amino acid having 1 to 10 carbon atoms, carbamic acid, alanine, glycine, asparagine, aspartic acid, sarcosine, serine, glutamine, glutamic acid, 4-aminobutyric acid, iminodibutyric acid, arginine, leucine, isoleucine, nitrilotriacetic acid, etc. Is preferably mentioned.

  Among the above organic acids, glycolic acid and malic acid can be suitably used as the acidic organic acid. In particular, glycolic acid and malic acid can obtain suitable properties by using two types simultaneously. The acidic organic acid is preferably contained in an amount of 1% by mass to 7% by mass with respect to the total amount of the etching solution.

  Moreover, when using glycolic acid and malic acid simultaneously, 0.5 mass% or more and 5.00 mass% or less are preferable with respect to the etching solution whole quantity, and, as for glycolic acid, 1.00 mass% or more 2.00 mass% is more preferable. It is preferable to contain by mass% or less. Further, the malic acid is preferably 0.10% by mass or more and 1.00% by mass or less, and more preferably 0.50% by mass or more and 0.80% by mass or less based on the total amount of the etching solution.

  Moreover, glycine, alanine or beta-alanine can be suitably used as a neutral organic acid. The neutral organic acid is preferably contained in an amount of 0.10% by mass or more and 3.00% by mass or less based on the total amount of the etching solution.

<Amine compound>
The amine compound is mainly responsible for adjusting the pH of the etching solution. As an amine compound, a C2-C10 thing can utilize suitably. More specifically, ethylenediamine, trimethylenediamine, tetramethylenediamine, 1,2-propanediamine, 1,3-propanediamine, N, N-dimethyl-1,3-propanediamine, N, N-diethyl-1 , 3-propanediamine, 1,3-diaminobutane, 2,3-diaminobutane, pentamethylenediamine, 2,4-diaminopentane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, N-methyl Ethylenediamine, N, N-dimethylethylenediamine, trimethylethylenediamine, N-ethylethylenediamine, N, N-diethylethylenediamine, triethylethylenediamine, 1,2,3-triaminopropane, hydrazine, tris (2-aminoethyl) amide , Polyamines such as tetra (aminomethyl) methane, diethylenetriamine, triethylenetetramine, tetraethylpentamine, heptaethyleneoctamine, nonaethylene decamine, diazabicycloundecene, etc .; N-ethyl ethanolamine, N-aminoethyl ethanolamine, N-propyl ethanolamine, N-butyl ethanolamine, diethanolamine, triethanolamine, 1-amino-2-propanol, N-methylisopropanolamine, N-ethylisopropanol Amine, N-propylisopropanolamine, 2-aminopropan-1-ol, N-methyl-2-amino-propan-1-ol, N-ethyl-2-amino Propan-1-ol, 1-aminopropan-3-ol, N-methyl-1-aminopropan-3-ol, N-ethyl-1-aminopropan-3-ol, 1-aminobutan-2-ol, N -Methyl-1-aminobutan-2-ol, N-ethyl-1-aminobutan-2ol, 2-aminobutan-1-ol, N-methyl-2-aminobutan-1-ol, N-ethyl-2-aminobutane- 1-ol, 3-aminobutan-1-ol, N-methyl-3-aminobutan-1-ol, N-ethyl-3-aminobutan-1-ol, 1-aminobutan-4-ol, N-methyl 1-aminobutane -4-ol, N-ethyl-1-aminobutan-4-ol, 1-amino-2-methylpropan-2-ol, 2-amino-2-methylprop -1-ol, 1-aminopentan-4-ol, 2-amino-4-methylpentan-1-ol, 2-aminohexan-1-ol, 3-aminoheptan-4-ol, 1-aminooctane -2-ol, 5-aminooctan-4-ol, 1-aminoppane-2,3-diol, 2-aminopropane-1,3-diol, tris (oxymethyl) aminomethane, 1,2-diaminopropane- Preferred examples include alkanolamines such as 3-ol, 1,3-diaminopropan-2-ol, 2- (2-aminoethoxy) ethanol, 2- (2-aminoethylamino) ethanol and diglycolamine. It can be used alone or in combination of two or more. Among these, 1-amino-2-propanol is particularly preferable. The amine compound is preferably contained in an amount of 0.50% by mass or more and 2.00% by mass or less, more preferably 0.75% by mass or more and 1.50% by mass or less based on the total amount of the etching solution. .

<Hydrogen peroxide decomposition inhibitor>
In the etching solution according to the present invention, hydrogen peroxide is used as the oxidizing agent. Since hydrogen peroxide is self-decomposable, a decomposition inhibitor that suppresses its decomposition is added. It is for lengthening the life of the etching solution. As a main hydrogen peroxide decomposition inhibitor, in addition to urea based hydrogen peroxide stabilizers such as phenylurea, allylurea, 1,3-dimethylurea and thiourea, phenylacetic acid amide, phenylethylene glycol, 1-propanol, Lower alcohols such as 2-propanol and ethers such as 2-butoxyethanol (ethylene glycol monobutyl ether) are preferably mentioned.

  Moreover, although it becomes clear also from the Example mentioned later, the said hydrogen peroxide decomposition inhibitor improves the hydrogen peroxide decomposition inhibitory effect by the coexistence of the acidic organic acid malic acid. These substances are considered to act on hydrogen peroxide and to suppress the decomposition of hydrogen peroxide by suppressing the generation of radicals.

<Copper ion>
In the etching solution according to the present invention, it was confirmed that when the etching progresses and Cu ions or Mo ions are contained, the etching rate changes according to the increase of the Cu ion concentration. Since the operation of the etching apparatus is controlled by adding the etching concentrate and the hydrogen peroxide solution so that the change of the etching rate falls within a certain allowable range, the condition of the new solution should be within this tolerance. Is preferred. Therefore, the etching solution may contain Cu ions in a predetermined range. Specifically, if the Cu ion is contained in an amount of 500 ppm or more and 7000 ppm or less, preferably 2000 ppm or more and 4000 ppm or less based on the total amount of the etching solution, change in the etching rate can be easily assumed.

  Similarly, the etching solution according to the present invention may contain molybdenum ions. Mo ions are approximately one tenth of Cu ions. Therefore, Mo ions may be contained at 50 or more and 700 ppm or less, preferably 200 ppm or more and 400 ppm or less.

<Others>
In addition to these components, various additives which are usually used may be added to the etching solution of the present invention as long as water and etching performance are not impaired. Since water is intended for precision processing, it is desirable that there be no foreign matter present. Pure water or ultrapure water is preferred.

<PH, temperature>
The etching solution according to the present invention is preferably used in the range of pH 2 to 5, more preferably pH 3 to 4.5, and most preferably pH 3.3 to 3.9. The etching solution according to the present invention can be used between 18 ° C. and 40 ° C. The temperature is more preferably 18 ° C. or more and 35 ° C. or less, and most preferably 20 ° C. or more and 32 ° C. or less.

<Save>
Hydrogen peroxide is used in the etching solution according to the present invention. Hydrogen peroxide self decomposes. Therefore, the etching solution contains a hydrogen peroxide decomposition inhibitor. However, at the time of storage, the hydrogen peroxide solution and the other liquid may be stored separately. Alternatively, a raw material from which hydrogen peroxide and copper ions have been removed (referred to as "etching liquid raw material") and water may be mixed to prepare a solution of the etching liquid raw material. This solution may be water in a proportion smaller than the proportion of water in the etching solution shown in the examples described later.

  A solution of an etching solution raw material prepared by mixing an etching solution raw material and water is called "etching concentrate". The etching concentrate has a smaller volume than the etching solution due to the absence of hydrogen peroxide, which is convenient for storage and transfer. Furthermore, in order to further reduce the volume during storage and transfer, the "etching concentrate" may be a "etching concentrate" in which water is reduced. The etching highly concentrated solution refers to one containing 20% or more and 70% or less of water. The etch concentrate contains more than 70% water. Therefore, the etching solution of the present invention may be completed by combining the etching concentrate and the hydrogen peroxide solution, or may be completed by combining the etching highly concentrated solution, the water, and the hydrogen peroxide solution.

<Etching method>
An object using the etching solution according to the present invention is a multilayer film of a copper layer / molybdenum layer in which molybdenum is a lower layer and copper is an upper layer. The thickness of the lower molybdenum layer is thinner than the thickness of the upper copper. When the thickness of the lower layer is t0 and the thickness of the upper layer is t1, the range of t0 / t1 is in the range of 0.01 or more and 0.2 or less. If the range of t0 / t1 is out of this range and the Mo layer is too thick, residues of the Mo layer tend to be generated, and conversely, if it is too thin, the Cu layer does not serve as an underlayer.

  There are no particular limitations on the substrate and the underlayer on which the molybdenum layer and the copper layer are formed, and glass, silicon, amorphous silicon, IGZO (Indium, Gallium, Gallium, Zinc, oxygen ( It may be a metal oxide such as an amorphous semiconductor composed of Oxide).

  The etchant according to the present invention can be stored by storing the hydrogen peroxide solution, the etching high concentrate and the water (the hydrogen peroxide solution and the etching concentrate may be separated) separately during storage. Become. Therefore, in actual use, these are mixed to complete the etching solution. The method of preparation is not limited as long as the concentration of hydrogen peroxide finally reaches a predetermined concentration.

  As an example, an etching concentrate prepared by mixing an etching solution raw material with a fixed amount of water is prepared. The hydrogen peroxide is usually supplied as a hydrogen peroxide solution having a concentration higher than the hydrogen peroxide concentration of the etching solution according to the present invention. Therefore, the hydrogen peroxide solution and the etching concentrate are prepared in predetermined amounts. This step may be called a step of preparing a multilayer film etching solution. Alternatively, the etching solution may be prepared by mixing an etching high concentration solution higher in concentration than the etching concentration solution, water, and a hydrogen peroxide solution.

  Copper ions may be mixed at any time when preparing etching concentrate (or etching high concentrate) with etching solution raw material and water, or when preparing etching solution with etching concentrate and hydrogen peroxide solution. it can. Of course, it may be added after preparing the etching solution. In the case where the etching concentrate and the hydrogen peroxide solution are additionally added to the etching solution already used, it is not necessary to put copper ions. This is because copper ions already exist in the etching solution.

  When the etching is performed, as described above, the etching solution is used under the conditions of pH 2 to 5 and 18 ° C. to 40 ° C. Therefore, it is desirable that the object to be etched be preheated to this temperature. The method for bringing the substrate to be treated into contact with the etching solution is not particularly limited. As in the shower type, the etching solution may be dispersed to the substrate to be processed from above, or a method of dipping the substrate to be processed in a pool of etching solution may be used. This step may be called a step of bringing the etching solution for multilayer film into contact with the substrate to be treated.

  In addition, with a to-be-processed substrate, a molybdenum layer (Mo layer) and a copper layer (Cu layer) are laminated on base materials, such as glass, and the pattern of the resist layer for pattern formation is formed in this laminated film. The substrate in the

<Description of various evaluation methods>
For the etching solution according to the present invention, the etching rate (nm / min) of copper and molybdenum, taper angle (°) of the cross section of the etched wiring, undercutting of the molybdenum layer, molybdenum layer remaining on the substrate ( The evaluation was made in terms of “Mo residue”, over etching resistance, presence or absence of precipitates, and hydrogen peroxide decomposition rate (% by mass / day).

  The etching rate was measured as follows. First, a single-layer film was formed to a thickness of 300 nm for copper and 150 nm for molybdenum by sputtering on a silicon wafer on which a thermal oxide film of 100 nm was formed. The copper film and the molybdenum film were brought into contact with an etching solution at 30 ° C. (or 35 ° C. depending on a comparative example) for 20 to 60 seconds.

  The resistance value of the film before and after etching was measured using a four-terminal four-point probe resistivity meter (Mitsubishi Chemical Analytech: MCP-T610 type) of a constant current application method. The change in film thickness was calculated from the change in resistance value to calculate the etching rate.

  The taper angle (referred to as "taper angle" in the following table) was measured as follows. First, a molybdenum layer was formed to a thickness of 20 nm by a sputtering method on a glass substrate, and a copper layer was subsequently formed to a thickness of 300 nm, thereby forming a Cu / Mo multilayer film sample. A resist patterned in a wiring shape was formed on this copper layer, and used as a substrate for taper angle evaluation. That is, the taper angle evaluation substrate comprises a substrate, a molybdenum layer, a copper layer thereon, and a patterned resist layer on the copper layer. Etching was performed by immersing the base material for evaluation of taper angle in an etching solution for the time of just etching. After the sample after etching was washed and dried, the wiring portion was cut and the cut surface was observed.

  The observation of the cut surface was performed using an SEM (Scanning Electron Microscope) (manufactured by Hitachi: SU 8020) under conditions of an acceleration voltage of 1 kV and 30,000 to 50,000 times. Just etching is the time from the start of etching to the passage of light through the film. The point in time when the film transmitted light was checked visually.

  The cross-sectional shape is shown in FIG. As shown in FIG. 1A, an angle 5 between the substrate 1 and the etched inclined surface 6 is defined as a taper angle (°). When the taper angle 5 was 30 ° or more and 60 ° or less, it was judged as a circle (o). If it was out of the range of this angle, it was judged as cross (x). Note that "Mar" means success or pass, and "cross" means failure or fail. The same is true for the following evaluations. In FIG. 1A, the Mo layer is represented by 3; the Cu layer is represented by 2; and the resist layer is represented by 4. The thickness of the Cu layer 2 is t1, and the thickness of the Mo layer 3 is t0.

  The undercut of the molybdenum layer 3 (referred to as “Mo undercut” in the following table) etches between the molybdenum layer 3 and the substrate 1 faster than the copper layer 2 as indicated by the reference numeral 10 in FIG. State (reverse taper). The evaluation can be performed simultaneously with the evaluation of the taper angle 5. The undercut 10 of the molybdenum layer 3 was judged as a circle (○) if it was not found by observation at 30,000 to 50,000 times the SEM, and it was judged as a cross when it was found.

  Mo residue (denoted as "Mo residue" in the following table) was determined to be x (x) if the residue was confirmed and x (o) if it was not confirmed by observation with an optical microscope and SEM. The optical microscope was observed at a magnification of about 100 times by bright field observation and dark field observation. Moreover, it observed by 30,000 to 50,000 times by SEM.

  Over etching resistance (referred to as “O.E. resistance” in the following table) means taper angle 5 when etched for twice the time taken for just etching, undercut 10 of molybdenum layer 3, Mo residue Was observed, and it was judged that all were "Mar" (○) if "Mar" evaluation. If any one was judged "cross", it was marked as cross (x).

  After preparing the etching solution, the presence or absence of the precipitate was left to stand at room temperature in the bottle for a predetermined time (several days) after the preparation of the etching solution, and it was visually judged whether the precipitate was generated in the bottle. If precipitates are generated, the etching solution is filtered through filter paper, and the foreign matter remaining on the filter paper is washed with pure water and dried at room temperature, and the obtained crystals or powder are FT-IR (IR affinity manufactured by Shimadzu Corporation) And SEM-EDX (manufactured by Horiba, Ltd.). When the precipitate was not visually observed, it was judged as a circle (○), and when visually confirmed, it was judged as a cross (×).

  It is important that the etching solution does not generate precipitates and that the cross-sectional shape of the wiring is appropriate, but in order to extend the bath life, the decomposition rate of hydrogen peroxide is also an important item. Here, the hydrogen peroxide decomposition rate was also examined as an evaluation item for reference.

  The hydrogen peroxide decomposition rate (referred to as “peroxide decomposition rate” in the following table), the hydrogen peroxide concentration immediately after preparation of the etching solution and after a predetermined time (about 24 hours), the titrant reagent potassium permanganate , And an automatic titrator (GP-200 manufactured by Mitsubishi Chemical Analytech Co., Ltd.). Then, the decomposition rate was calculated from the amount of change in the hydrogen peroxide concentration.

  If the reduction amount of the hydrogen peroxide concentration after 24 hours is less than 0.24 mass%, it is evaluated as a double circle (◎), and if it is 0.24 mass% or more and 0.96 mass% or less, It evaluated as (circle)) and evaluated as x (x) when it exceeds 0.96 mass%. The reduction amount of the hydrogen peroxide concentration after 24 hours is described as, for example, “0.24 mass% / day”. Here, the double circle means that it is a particularly desirable result among the pass criteria. In addition, for all the evaluations, although the conditions of the round evaluation were not satisfied, in the case of a value extremely close to the boundary value, it was evaluated as a triangle (Δ).

Example 1
1.29% by mass of nitric acid,
1.14% by weight of glycolic acid,
0.85% by weight of malic acid,
1.42% by mass of β-alanine,
1.71% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
1.16% by mass of 1-propanol
1.29% by mass of 2-butoxyethanol
The etching liquid raw material which consists of these is mixed with 91.03 mass% of water, and the etching concentrate was prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 30 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 1. Further, the concentration of each component in the entire etching solution is shown in Table 3.

  In Tables 1 to 4, 2-butoxyethanol is described as "BG (2-butoxyethanol)." Moreover, the hydrogen peroxide concentration shown in Table 1 and Table 2 represents the hydrogen peroxide concentration with respect to the whole etching liquid.

(Example 2)
0.09 mass% nitric acid,
1.44% by weight of glycolic acid,
0.86% by weight of malic acid,
0.91% by mass of β-alanine,
0.87% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
1.15% by mass of 1-propanol
1.28% by mass of 2-butoxyethanol
The etching liquid raw material which consists of these is mixed with 93.29 mass% of water, and the etching concentrate was prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 30 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 1. Further, the concentration of each component in the entire etching solution is shown in Table 3.

(Example 3)
0.18% by mass of nitric acid,
1.30% by weight of glycolic acid,
0.87% by weight of malic acid,
0.91% by mass of β-alanine,
0.86% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
1.16% by mass of 1-propanol
1.28% by mass of 2-butoxyethanol
The etching liquid raw material which consists of these is mixed with 93.33 mass% of water, and the etching concentrate was prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 30 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 1. Further, the concentration of each component in the entire etching solution is shown in Table 3.

(Example 4)
1.29% by mass of nitric acid,
1.14% by weight of glycolic acid,
0.85% by weight of malic acid,
1.42% by mass of β-alanine,
1.71% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
1.16% by mass of 1-propanol
The etching liquid raw material which consists of these is mixed with 92.32 mass% of water, and the etching concentrate was prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 30 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 1. Further, the concentration of each component in the entire etching solution is shown in Table 3.

(Example 5)
1.29% by mass of nitric acid,
1.14% by weight of glycolic acid,
0.85% by weight of malic acid,
1.42% by mass of β-alanine,
1.71% by mass of 1-amino-2-propanol,
1.16% by mass of 1-propanol
1.29% by mass of 2-butoxyethanol
The etching liquid raw material which consists of these is mixed with 91.14 mass% of water, and the etching concentrate was prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 30 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 1. Further, the concentration of each component in the entire etching solution is shown in Table 3.

(Example 6)
1.29% by mass of nitric acid,
1.14% by weight of glycolic acid,
0.85% by weight of malic acid,
1.42% by mass of β-alanine,
1.71% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
1.29% by mass of 2-butoxyethanol
The etching liquid raw material which consists of these is mixed with 92.19 mass% of water, and the etching concentrate was prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 30 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 1. Further, the concentration of each component in the entire etching solution is shown in Table 3.

(Example 7)
1.29% by mass of nitric acid,
1.14% by weight of glycolic acid,
0.85% by weight of malic acid,
1.42% by mass of β-alanine,
1.71% by mass of 1-amino-2-propanol,
1.16% by mass of 1-propanol
The etching liquid raw material which consists of these is mixed with 92.43 mass% of water, and the etching concentrate was prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 30 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 1. Further, the concentration of each component in the entire etching solution is shown in Table 3.

(Example 8)
1.29% by mass of nitric acid,
1.14% by weight of glycolic acid,
0.85% by weight of malic acid,
1.42% by mass of β-alanine,
1.71% by mass of 1-amino-2-propanol,
1.29% by mass of 2-butoxyethanol
The etching liquid raw material which consists of these is mixed with 92.30 mass% of water, and the etching concentrate is prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 30 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 1. Further, the concentration of each component in the entire etching solution is shown in Table 3.

(Comparative example 1)
0.17% by mass of nitric acid,
2.38% by weight of glycolic acid,
0.85% by mass of glutamic acid
0.42% by mass of aspartic acid,
0.65% by mass of β-alanine,
1.55% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
1.13 mass% of 1-propanol
The etching liquid raw material which consists of these is mixed with 92.74 mass% of water, and the etching concentrate is prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 30 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 2. Further, the concentration of each component in the entire etching solution is shown in Table 4.

(Comparative example 2)
0.35 mass% nitric acid,
2.90% by weight of glycolic acid,
0.66% by mass of β-alanine,
1.77% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
1.17% by mass of 1-propanol
The etching liquid raw material which consists of these is mixed with 93.04 mass% of water, and the etching concentrate was prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 25 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 2. Further, the concentration of each component in the entire etching solution is shown in Table 4.

(Comparative example 3)
1.30% by mass of nitric acid,
0.65% by weight of glycolic acid,
3.57% by mass of lactic acid
1.43% by mass of β-alanine,
2.55% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
1.14 mass% of 1-propanol
The etching liquid raw material which consists of these is mixed with 89.25 mass% of water, and the etching concentrate was prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 27.5 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 2. Further, the concentration of each component in the entire etching solution is shown in Table 4.

(Comparative example 4)
0.53% by mass of nitric acid,
2.74% by weight of glycolic acid,
1.45 mass% of succinic acid
1.44% by mass of β-alanine,
1.75% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
1.14 mass% of 1-propanol
The etching liquid raw material which consists of these was mixed with 90.84 mass% of water, and the etching concentrate was prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 25 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 2. Further, the concentration of each component in the entire etching solution is shown in Table 4.

(Comparative example 5)
1.29% by mass of nitric acid,
1.14% by weight of glycolic acid,
0.85% by weight of malic acid
1.42% by mass of β-alanine,
1.71% by mass of 1-amino-2-propanol,
0.11% by mass of phenylurea,
The etching liquid raw material which consists of these is mix | blended with 93.48 mass% of water, and the etching concentrate was prepared.

  The hydrogen peroxide and the etching concentrate were mixed to prepare an etching solution having a hydrogen peroxide concentration of 4.50% by mass. Further, copper sulfate and molybdenum powder were added to prepare a copper ion concentration of 2000 ppm and a molybdenum ion concentration of 200 ppm. The solution temperature was 30 ° C. The concentration of each component in the etching concentrate and the result of each evaluation item are shown in Table 2. Further, the concentration of each component in the entire etching solution is shown in Table 4.

<Result>
Examples 1 to 8 are etching solutions according to the present invention. Since it does not contain an azole compound, it does not form a reactant with hydrogen peroxide, and there is no precipitate. As the acidic organic acid, glycolic acid and malic acid were simultaneously used. These samples were free of precipitates, and had taper angles, Mo undercuts, Mo residues, O.I. E. All items of resistance were also evaluated as a circle. Furthermore, the hydrogen peroxide decomposition rate was also less than 0.96% by mass / day, and the desired result could be obtained.

  Further, since the over-etching resistance was good, etching could be performed while maintaining a good taper angle from the time spent for just etching to twice the time. Moreover, even if the film thickness ratio (t0 / t1) of Mo and Cu differs from the case (20/300) in the case of the embodiment, the film thickness ratio is 0.01 or more and 0.2 or less in these embodiments. The taper angle of 30 ° or more and 60 ° or less could be realized if

  In Examples 1, 5, 6, and 8, the decomposition rate of hydrogen peroxide was extremely low, and a long pot life could be realized. As for the correspondence with the composition at this time, when the nitric acid concentration is 1.0% by mass or more with respect to the total amount of the etching solution and 2-butoxyethanol is contained (acidic organic acid, neutral organic acid, The decomposition rate of hydrogen peroxide was suppressed by the amine compound, of course.

  As a hydrogen peroxide decomposition inhibitor, phenyl urea, 1-propanol, 2-butoxyethanol was used, but the decomposition rate of hydrogen peroxide was suppressed if at least 1-propanol and 2-butoxyethanol were included. . However, even when 1-propanol was contained as in Comparative Example 1, decomposition of hydrogen peroxide could not be suppressed if malic acid was not contained. From this, it can be concluded that the hydrogen peroxide decomposition inhibitor was able to effectively suppress the decomposition of hydrogen peroxide when used together with malic acid.

  Moreover, although the comparative example 5 is an example using phenylurea and malic acid, hydrogen peroxide decomposition was not able to be suppressed like each sample of an Example. However, as can be seen from the results of each sample, it can be used with 1-propanol and / or 2-butoxyethanol.

  The precipitates were observed in Comparative Examples 2 and 4. Therefore, in Comparative Example 2, the physical properties other than the precipitates were not measured. The cause of the occurrence of precipitates is not clear. However, when the concentration of glycolic acid exceeds 2.1% by mass with respect to the total amount of the etching solution, a deposit is generated.

  As already mentioned, the etching solution according to the invention can be handled as an etching concentrate without the addition of hydrogen peroxide. That is, the etching solution can be used as an etching solution according to the present invention as shown in Table 3 (Table 4 for Comparative Example) by mixing a 35 wt% hydrogen peroxide solution and the etching concentrate. Table 1 (for the comparative example, Table 2) shows the composition ratio in the etching concentrate which does not contain hydrogen peroxide.

  Therefore, the composition ratio as an etching solution of each constituent material and the composition ratio as an etching concentrate can be reread using Tables 1 and 2 and Tables 3 and 4, respectively. For example, taking Example 1 as an example, nitric acid is 1.29% by mass in the etching concentrate of Table 1, but 1.13 mass in the etching solution of Table 3 (in a state where hydrogen peroxide is added). It becomes%.

  The etching solution of the present invention is not limited to products such as liquid crystal displays, plasma displays, FPDs such as organic EL, etc. Substrates such as glass substrates, silicon substrates, amorphous silicon substrates, metal oxide substrates or underlayers made of these materials In the aspect using the wiring in which the molybdenum layer and copper layer which were formed on top were laminated | stacked, it can utilize widely.

1 substrate 2 copper layer 3 molybdenum layer 4 resist (layer)
5 taper angle 6 slope 10 undercut part

Claims (10)

With hydrogen peroxide,
Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
An etching solution for a multilayer film comprising a copper layer and a molybdenum layer, which contains a hydrogen peroxide decomposition inhibitor and does not contain an azole compound, a phosphorus compound, and a fluorine compound.   The etching solution for a multilayer film according to claim 1, wherein the inorganic acid is nitric acid.   The etching solution for a multilayer film according to any one of claims 1 and 2, wherein the acidic organic acid comprises two types of glycolic acid and malic acid.   The etching solution for a multilayer film according to any one of claims 1 to 3, wherein the neutral organic acid is β-alanine.   The multilayer amine etching solution according to any one of claims 1 to 4, wherein the amine compound is 1-amino-2-propanol.   The etching for a multilayer film including a copper layer and a molybdenum layer according to any one of claims 1 to 5, wherein the hydrogen peroxide decomposition inhibitor contains at least one of a lower alcohol and an ether. liquid.   The etching solution for a multilayer film containing a copper layer and a molybdenum layer according to any one of claims 1 to 6, further containing 500 ppm or more and 7000 ppm or less of copper ions. Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
Hydrogen peroxide decomposition inhibitor,
Water only containing an azole compound and a phosphorus compound, a multilayer film for etching concentrate containing copper layer and a molybdenum layer, wherein the fluorine-free compound. Inorganic acid,
With an acidic organic acid,
Neutral organic acid,
An amine compound,
Look containing hydrogen peroxide decomposition inhibitor and water, and the azole compound, a phosphorus compound, a step of preparing the multi-layer film for an etching solution formulated an etching concentrate and water and hydrogen peroxide containing no fluorine compound,
A method of etching a multilayer film comprising a copper layer and a molybdenum layer, comprising the step of bringing the etching solution for multilayer film into contact with a substrate to be treated. In the step of bringing the etching solution for multilayer film into contact with the substrate to be treated,
The multilayer film according to claim 9, characterized in that the pH of the etching solution for a multilayer film is in the range of 2 to 5, and the solution temperature is 18 to 35 ° C. How to etch film.