JP2012049535A - Etchant composition for multiple film and etching method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an etchant composition which can efficiently, excellently, simultaneously and collectively etch a multiple film including a copper layer comprises one or more layers of copper or copper alloy such as a Cu/Mo laminated metal film, a Cu/Mo alloy laminated metal film and a Cu alloy/Mo alloy laminated metal film, and a molybdenum layer comprises one or more layers of molybdenum or molybdenum alloy, and to provide a etching method for the multiple film using the same.SOLUTION: The etchant composition contains 50-80 wt.% of phosphoric acid, 0.5-10 wt.% of nitric acid, 5-30 wt.% of acetic acid, 0.01-5 wt.% of imidazole with respect to the total weight, and the balance water. The imidazole as an additive functions as a copper/molybdenum galvanic reaction controller.

Description

  The present invention relates to an etching solution for patterning a conductive layer used in a TFT (Thin Film Transistor) or a touch sensor panel of a flat panel display. More specifically, a multilayer film including one or more copper layers of copper (Cu) or a copper alloy (Cu alloy) and one or more molybdenum layers of molybdenum (Mo) or a molybdenum alloy (Mo alloy) is etched. In particular, the present invention relates to an etching solution for collectively etching a Cu / Mo double film. The present invention also relates to a method for etching a multilayer using such an etchant.

  Conventionally, a single film of copper (Cu) cannot be used as a low-resistance metal electrode, and after forming a molybdenum (Mo) or titanium (Ti) film as a diffusion prevention film on the lower part of copper, pure copper ( By forming Cu), a TFT gate electrode and a source / drain electrode are formed by a Cu / Mo or Cu / Ti double film.

  When a conventional phosphoric acid-based mixed acid is used for the double-film etching solution as described above, it is impossible to form a desired pattern that satisfies the conditions of TFT, and a hydrogen peroxide-based (unstable and waste liquid amount is low). However, if mixed acid containing a small amount of fluorine ions is used as an etchant, if the amount is too large, the glass used as the substrate will be etched. There was a problem to make.

  In addition, when a composition of phosphoric acid + nitric acid + acetic acid + water, which is a conventional mixed acid aluminum etching solution, is used, there is a problem that it is difficult to form a desired TFT pattern because the etching rate is very high. Therefore, a control agent for controlling (lowering) the Cu etching rate, that is, a Cu etching rate controlling agent is required.

  Patent Document 1 discloses an etching solution containing hydrogen peroxide capable of collectively etching a Cu / Mo laminated metal film (or Cu alloy / Mo alloy laminated metal film). In the case of the hydrogen peroxide mixed solution, there is a drawback that the concentration changes with time, and in particular, there is a problem in the safety of the etching solution.

  Recently, a hydrogen peroxide mixed solution has attracted attention as an etching solution. However, when a metal is generally contained in hydrogen peroxide, a decomposition reaction of hydrogen peroxide is caused by the metal, resulting in an unstable state. More specifically, the rapid decomposition reaction of hydrogen peroxide causes a change in concentration over the course of the etching process, that is, over time, and the temperature of the etching solution rises rapidly, there is a risk of explosion, and additional equipment is required. Since there are problems such as an increase in manufacturing cost, there are many problems in using a hydrogen peroxide mixture as an etching solution.

  As described above, the existing hydrogen peroxide-based etching solution has a problem of explosiveness (chemical solution safety such as generation of wastewater treatment problems) and short life. In particular, in the case of a Cu / Mo double film, a fluorine-containing compound (fluorine compound) must be added to the etching solution in order to remove the Mo residue, which damages the glass substrate.

Therefore, in order to solve the above-mentioned problems, a non-hydrogen peroxide / non-fluorine compound system (Non-hydrogen peroxide (H ₂ O ₂ ) / Non—) capable of simultaneously etching a Cu / Mo multilayer film simultaneously. There is a demand for the development of a new etching composition based on fluorine compound.

  Copper etching including phosphoric acid, nitric acid, acetic acid and other additives has been proposed in Patent Documents 2 and 3, etc., but the specific application results for the Cu / Mo multilayer structure have not been clarified, 1 for Cu / Mo multi-layered film even without environmental harmful substances such as hydrogen peroxide (a large amount of waste liquid), unstable components that shorten the etching life, or fluorine compounds that corrode the glass of the substrate. Development of a novel etchant composition capable of obtaining an excellent etching profile by only one wet etching process is required.

  By the way, it is known that a galvanic reaction occurs between different kinds of metals such as a Cu / Mo multilayer film. A galvanic reaction is a phenomenon that occurs when different metals are brought into contact with each other in solution or in the atmosphere. This is a phenomenon in which the etching rate changes significantly due to the difference in electrochemical electromotive force in the electrolyte between different kinds of metals. The rate of oxidation and reduction reaction of the two metals is determined by the relative potential difference in the solution of the two metals. In general, the higher the electrochemical potential of the two metals in the solution, the more noble acts as a cathode and the reduction reaction becomes more dominant, and the etching rate is slower than in the case of a single film. The relatively low potential metal acts as an anode, further promoting the oxidation reaction and increasing the etching rate compared to a single film.

  These studies confirmed that the potential of copper and molybdenum changes greatly depending on whether or not nitric acid is added as a phosphoric acid-based etching solution. Prior to nitric acid addition, copper acted as a cathode by having a higher potential than molybdenum. However, after adding nitric acid as an oxidant, copper has a lower potential than molybdenum, thereby acting as an anode and causing an over-etching phenomenon. That is, when copper and molybdenum have different etching rates in the same etching solution, copper is over-etched before the molybdenum is etched, so that straightness is lowered and the resistance of all wirings is increased.

  In order to make up for such problems, when two or more kinds of etchants having different compositions for copper and lower wiring (Mo and Ti) are used, the entire etching process becomes complicated, and the manufacturing cost and There is a problem that the productivity increases with time. In order to simplify the process and reduce the manufacturing cost, an etching solution capable of etching a multilayer film such as a Cu / Mo double wiring at a time is required.

  In addition, the current thin film transistor wiring process is applied to a large area substrate in order to simplify the metal wiring patterning process in order to reduce the manufacturing cost. Therefore, the etching process is uniform regardless of the material forming the multilayer film. There is a need for the development of new etchant compositions that exhibit etching characteristics.

  In addition, as proposed in Patent Documents 4 and 5, metal conductive multiple thin films are also of (projected) capacitive or resistive touch sensor structures. Is necessary for. The touch sensor structure is formed, for example, inside or outside a color filter substrate of a TFT-LCD, or on an additional substrate disposed in front of the display.

  The small touch sensor has a circuit formed of a single layer of molybdenum (Mo), MoTa, or MoTa alloy, and a transparent conductive film, for example, indium tin oxide (ITO), is attached to the sensor structure. Have. In addition, multiple films such as Al / Mo, AlNd / Mo, and AlNd / Mo alloys are also used as the conductive film. However, since a large resistance touch screen needs to be made of a low resistance metal, a Cu / Mo or Cu / Mo alloy multilayer film is used as a result.

  The patterning of the metal wiring is preferably accomplished by wet etching, and the patterning problems of these metal multilayers for the touch sensor are similar to those associated with thin film transistors.

International Publication No. 2009/038063 Korean Published Patent No. 10-2009-0095408 Korean Published Patent No. 10-2006-0082270 US Patent Application Publication No. 2009/0160824 US Patent Application Publication No. 2009/0096759

  In order to solve the problems of the prior art as described above, the present invention provides a copper or copper alloy including a Cu / Mo laminated metal film, a Cu / Mo alloy laminated metal film, and a Cu alloy / Mo alloy laminated metal film. Multiple layers including one or more copper layers and one or more molybdenum layers of molybdenum or molybdenum alloy are simultaneously etched to simplify the manufacturing process, which not only saves manufacturing costs and time, but also It is an object of the present invention to provide an etching solution composition having an excellent profile and etching characteristics, and excellent in chemical safety in the process, and a method for etching a multilayer film using the same.

  To achieve the above object, the multilayer film etching solution composition according to the present invention comprises 50 to 80 wt% phosphoric acid, 0.5 to 10 wt% nitric acid, and the total weight of the composition. It contains 5 to 30 wt% acetic acid and 0.01 to 5 wt% imidazole.

  The etching method according to the present invention includes a step of depositing a multilayer film including at least molybdenum or a molybdenum alloy film and copper or a copper alloy film on a substrate, and a photoresist film having a predetermined pattern on the multilayer film. Forming, using the photoresist film as a mask, 50 to 80 wt% phosphoric acid, 0.5 to 10 wt% nitric acid, and 5 to 30 wt% acetic acid based on the total weight of the composition; Etching the multilayer film using an etchant composition containing 0.01 to 5 wt% imidazole, forming a metal wiring, removing the photoresist film, and cleaning the metal wiring with deionized water And drying.

  The present invention includes a Cu / Mo laminated metal film, a Cu / Mo alloy laminated metal film, a Cu alloy / Mo alloy laminated metal film, one or more copper layers of copper or copper alloy, and one or more layers of molybdenum or molybdenum alloy. A multilayer film including the molybdenum layer can be etched simultaneously. For this reason, the manufacturing process and cost can be minimized, and excellent productivity can be provided because there is no damage to the equipment.

Step length that appears when a Cu / Mo double film is etched using the phosphoric acid + nitric acid + acetic acid + additive etchant (Comparative Example) proposed in one example of the prior art (Patent Document 3) It is a plane SEM photograph which shows (step length). It is a cross-sectional SEM photograph etched with the etching liquid composition of a comparative example. It is a plane photograph when etching the double film of Cu / Mo using the etching liquid containing phosphoric acid, nitric acid, acetic acid, additive imidazole (imidazole), and water of an example. It is a cross-sectional SEM photograph etched with the etching liquid composition of an Example. Is a graph showing changes in etching properties of Cu / Mo layer by the addition of imidazole _{(C 3 H 4 N 2)} . Is a graph showing changes in etching properties of Cu / Mo layer by addition to the aminotetrazole _(CH 3 _{N 5).} 6 is a graph showing changes in etching characteristics of a Cu / Mo layer comparing the effects of step lengths of imidazole and aminotetrazole.

  An etching solution composition according to an embodiment of the present invention (hereinafter also referred to as the present etching solution) is a non-hydrogen peroxide / non-fluorine compound phosphoric acid-based etching solution that improves an etching profile (step length). In order to reduce (step length) and CD (cut dimension) skew, imidazole is included as an additive.

  The phosphoric acid based etchant is more stable than the hydrogen peroxide type. According to the inventor's research, since the phosphoric acid-based etching solution is unlike the hydrogen peroxide-based etching solution, the problem of Mo residue hardly occurs, so this etching solution is mostly used for removing Mo residue. The fluorine compound, which is a component contained in the etching solution, is also unnecessary.

In addition, this etching solution is obtained by adding imidazole to a stable phosphoric acid etching solution (phosphoric acid + nitric acid + acetic acid + water). That is, this etching solution contains phosphoric acid (H ₃ PO ₄ ), nitric acid (HNO ₃ ), acetic acid (CH ₃ COOH), imidazole (C ₃ H ₄ N ₂ ), and water (H ₂ O). .

Preferably, the etching solution is 50 to 80 wt% phosphoric acid (H ₃ PO ₄ ), 0.5 to 10 wt% nitric acid (HNO ₃ ), and acetic acid (CH ₃ COOH) based on the total weight of the composition. 5 to 30 wt%, imidazole (C ₃ H ₄ N ₂ ) as an additive, 0.01 to 5 wt%, and the remaining amount of water.

More preferably, the etching solution composition is 50 to 75 wt% phosphoric acid, 1 to 9 wt% nitric acid, 14 to 20 wt% acetic acid, and imidazole (C ₃ H ₄ as an additive) with respect to the total weight of the composition. N ₂₎ the 0.1 to 0.3%, and water of the remaining amount.

  This etching solution is used when wet etching a multilayer film including one or more copper layers of copper or copper alloy and one or more molybdenum layers of molybdenum or molybdenum alloy. Preferably, it is used when etching these multiple films simultaneously.

  Examples of the multilayer film include a Cu / Mo laminated metal film, a Cu / Mo alloy laminated metal film, a Cu alloy / Mo alloy laminated metal film, and the like. Then, it can be used as an etching solution for etching.

  In addition, this etchant is an etchant for Cu / Mo bilayer film, which is based on phosphoric acid (phosphoric acid, nitric acid, acetic acid), and imidazole is added to reduce the galvanic effect. Further included as an agent. That is, imidazole functions as a copper / molybdenum galvanic reaction controller.

  Further, the present etching solution is a non-hydrogen peroxide / non-fluorine compound solution, and does not contain hydrogen peroxide and / or a fluorine compound as a constituent component. Since this etching solution is based on phosphoric acid which is more stable than hydrogen peroxide, it is possible to efficiently etch multiple films, particularly Cu (or Cu alloy) / Mo (or Mo alloy) multiple films simultaneously. .

  Water functions as a copper oxidant and is preferably included as a remaining amount in the etching solution. In general, when an excessive amount of water is included in the etching solution, the etching rate of copper is accelerated, and the galvanic phenomenon between copper and molybdenum is promoted, so that the difference between copper and molybdenum wiring width (step length) due to etching becomes large.

Phosphoric acid (H ₃ PO ₄ ) functions as a basic oxidant and is preferably contained in an amount of 50 to 80 wt% based on the total weight of the composition. When phosphoric acid is less than 50 wt%, the water content increases and an overetching phenomenon occurs, and when it exceeds 80 wt%, overetching and non-uniform etching occur. The higher the proportion of pure phosphoric acid, the better.

Nitric acid (HNO ₃ ) functions as a copper oxidant and is preferably contained in an amount of 0.5 to 10 wt% based on the total weight of the composition. When nitric acid is less than 0.5 wt%, the etching rate of copper is slow, and when nitric acid exceeds 10 wt%, the galvanic phenomenon of copper and molybdenum is promoted and the step length is abrupt. The etching rate of copper increases rapidly.

Acetic acid (CH ₃ COOH) functions as a regulating liquid for the galvanic phenomenon of copper and molybdenum, and is preferably contained in an amount of 5 to 30 wt% based on the total weight of the composition. When acetic acid is less than 5 wt%, a galvanic phenomenon of copper and molybdenum occurs, the step length increases, the copper etching rate is high, and overetching occurs. In addition, when acetic acid exceeds 30 wt%, the straightness of the pattern decreases.

When acetic acid is added, since the oxide film (CuO ₂ ) formed on the copper surface in the phosphoric acid solution is dissolved, the etching rate of copper is increased. In this study, it was confirmed that when acetic acid was added to the phosphoric acid solution, a molybdenum oxide film (MoO ₂ ) grew on the surface of the molybdenum, so that the etching rate of molybdenum was further reduced. Further, it was confirmed that as the acetic acid content in phosphoric acid increases, the total galvanic reaction is changed by the above-described action, and the step length and CD (cut dimension) Skew are reduced.

  In order to reduce such a galvanic effect, this etching solution further contains imidazole as an additive in phosphoric acid, nitric acid and acetic acid. The exact mechanism of imidazole in phosphoric acid is not known, but additives such as imidazole are adsorbed on the surface of copper or molybdenum, or complexed with etched copper and molybdenum ions to form a surface. It is believed that the subsequent copper / molybdenum etch rate is adjusted by laminating to. When the imidazole is contained in a certain amount or more, the etching rate of copper is suppressed, so that etching non-uniformity is rather caused.

  Therefore, in the present etching solution, imidazole is an additive functioning as a copper / molybdenum galvanic reaction controller, and is 0.01% relative to the total weight of the composition. It is preferable that -5 wt% is contained. More preferably, imidazole is contained at least 0.1 wt% or more, particularly preferably 0.1 to 0.3 wt%. When imidazole is less than 0.01 wt%, the occurrence of galvanic phenomenon between copper and molybdenum increases, and the step length, which is the difference in wiring width between copper and molybdenum (after etching, copper and molybdenum) The difference in wiring width is referred to as “step length”), and when it exceeds 5 wt%, the etching rate of copper decreases rapidly.

  The solution temperature when using this etching solution is preferably 30 ° C. to 60 ° C., particularly about 40 ° C. When the solution temperature was less than 30 ° C., CD (cut dimension) skew and step length non-uniformity occurred, and when it exceeded 60 ° C., an over-etching phenomenon was observed.

  Further, the thickness ratio of the copper layer and the molybdenum layer of the multilayer film to which the present etching solution is applied is preferably 30: 1 or more, and if it is less than that, the galvanic reaction becomes large and the step length (step length) is increased. When the thickness ratio between the copper layer and the molybdenum layer is 30: 1 or more, the galvanic phenomenon is reduced and the step length is reduced. The optimum thickness of Mo is preferably 100 angstroms, and the optimum thickness of Cu is preferably 3000 angstroms.

  The residual stress of the molybdenum film or molybdenum alloy film is preferably a tensile stress. In the case of a molybdenum vapor-deposited film, vapor deposition under process conditions with high argon pressure reduces the galvanic phenomenon with copper and is advantageous for forming a taper angle.

  The copper film or copper alloy film is preferably annealed at a temperature of 100 ° C. to 300 ° C. for 10 minutes to 1 hour after vapor deposition.

  This etchant can be advantageously used in the manufacture of flat panel display TFTs, active matrix OLEDs or touch sensor panels.

  In addition, the present etching solution composition may further contain usual additives such as a surfactant and an etching regulator, for example, and may further add other known additives as required for the intended etching characteristics. Can do.

  Due to the characteristics of the morribden film, a small particle residue is formed, and if it remains on the glass substrate or the lower film, it causes pixel defects. In order to remove the residue, most of the etching liquid contains a fluorine compound. Fluorine compounds have the effect of removing residues, but have the disadvantage of damaging the glass substrate.

  On the other hand, this etching liquid does not contain the fluorine compound added for the residue removal of Mo. The reason for this is that unlike a hydrogen peroxide-based etchant, a phosphoric acid-based etchant such as the present etchant hardly causes a problem of Mo residue, so that it is not necessary to add a fluorine compound to the etchant. Accordingly, it is possible to eliminate the defect that the glass substrate is damaged by the fluorine compound additive.

  An etching method using the present etching solution (hereinafter also referred to as the present etching method) includes a step of depositing a multilayer film including at least molybdenum or a molybdenum alloy film and a copper or copper alloy film on a substrate, Forming a photoresist film having a predetermined pattern; and using the photoresist film as a mask, 50 to 80 wt% phosphoric acid and 0.5 to 10 wt% nitric acid based on the total weight of the composition Forming a metal wiring by etching the multilayer film using an etchant containing 5-30 wt% acetic acid and 0.01-5 wt% imidazole; and removing the photoresist film And washing and drying the metal wiring with deionized water.

  Preferably, the multiple film includes one or more copper layers of copper or copper alloy, such as a Cu / Mo laminated metal film, a Cu / Mo alloy laminated metal film, a Cu alloy / Mo alloy laminated metal film, and the like. And one or more molybdenum layers of molybdenum or a molybdenum alloy.

  In this etching method, a molybdenum or molybdenum alloy film is deposited on the substrate, a copper or copper alloy film is deposited on the molybdenum or molybdenum alloy film, and a photoresist film is formed on the copper or copper alloy film. It is preferably applied to the laminated body.

  The molybdenum alloy contains molybdenum and preferably at least one element selected from tungsten, titanium, tantalum and niobium. The copper alloy contains copper and preferably at least one element selected from magnesium, molybdenum and manganese.

  Preferably, the molybdenum or molybdenum alloy film has a thickness of 100 to 500 angstroms, and the copper or copper alloy film has a thickness of 1000 to 20000 angstroms. In this range, efficient etching is possible. is there.

  Moreover, this etching method can be performed at the temperature of 30 to 60 degreeC, Preferably it is about 40 degreeC. When this etching solution is used, the metal wiring can be formed by spraying the etching solution on the substrate preferably by a spray method (spray method) for 30 seconds to 150 seconds. The copper or copper alloy film can be preferably formed as a source / drain electrode.

  The substrate is preferably a glass substrate for a TFT LCD, a metal thin film substrate for a flexible display, or a plastic substrate, and the substrate can be used for a TFT LCD, an active matrix OLED, or a touch sensor panel.

  Hereinafter, the present invention will be described in detail based on examples and comparative examples. In addition, the Example shown below is for describing this invention in detail, and does not limit the scope of the present invention.

  Here, the etching liquid compositions of Examples and Comparative Examples were produced, and the etching characteristics were evaluated. The evaluation of the etching characteristics was performed by the following experimental example.

[Experimental example]
Prepare a specimen in which a Cu / Mo double film was deposited on the substrate, put the etching solution of Example or Comparative Example in the experimental equipment of the jet etching system (manufactured by FNS Tech), and set the temperature to 40 ° C. When the temperature reached 40 ± 0.1 ° C., the substrate etching process was performed.

  The total etching time was overetched by 50% over the time detected by an end point detector (EPD). After completion of the etching, the substrate was taken out, washed with deionized water, and then dried with a hot air dryer. Further, the photoresist was removed with a photoresist (PR) stripper.

  Using an electron scanning microscope (SEM, manufactured by TESCAN), CD skew (Cut dimension skew) indicating the distance between the photoresist end and the copper end, and the step length (step length) which is the difference between the copper and molybdenum wiring width ), Etching residue, etc. were observed and evaluated.

[Comparative Example 1]
As mentioned in the background art, a copper etching solution containing phosphoric acid, nitric acid, acetic acid and other additives has been proposed in Patent Documents 2 and 3, etc., but is specific to the Cu / Mo dual structure. The application results are not disclosed. The technique described in Patent Document 3 as a conventional technique is an etching solution composition for metal electrodes for forming thin film transistors for flat panel displays, and is a composition of phosphoric acid + nitric acid + acetic acid + water, which is a conventional aluminum etching solution. Further, an etching rate adjusting agent is further added to form a desired pattern.

Then, the etching liquid composition of Example 1 described in patent document 3 as the comparative example 1 was manufactured. The composition of the etching solution composition of Comparative Example 1 is as follows.
H ₃ PO ₄ 55 wt%
HNO ₃ 8wt%
CH ₃ COOH 10wt%
(NH ₄ ) ₂ HPO ₄ 2 wt%
CH ₃ COONH ₄ 2wt%
H ₂ O remaining

  The etching characteristics of the etching solution composition of Comparative Example 1 having the composition were evaluated by the experimental example.

  FIG. 1 is a plan view showing a specific application result for a Cu / Mo double film of an etching solution containing phosphoric acid, nitric acid, acetic acid composition and additives proposed in the prior art (Patent Document 3) as a comparative example. It is.

  As shown in FIG. 1, when a phosphoric acid-based etching solution is applied to a Cu / Mo dual structure, molybdenum, which is a lower film, hardly dissolves, but the upper part is caused by a difference in etching rate between two kinds of metals and a galvanic corrosion phenomenon. The phenomenon that the copper of the film was over-etched occurred. The difference between the copper and molybdenum wiring width generated at this time was defined as a step length (see FIG. 1). According to FIG. 1, when etching a Cu / Mo double film with the etching solution of Comparative Example 1, a considerably large step length is generated, which indicates that the etching profile is poor.

  FIG. 2 is a cross-sectional SEM photograph etched with the etchant composition of Comparative Example 1. As shown in FIG. 2, there was a problem that CD skew (Cut dimension skew) indicating the distance between the photoresist end and the copper end was increased (etching failure). In order to perform uniform taper etching without a step, this distance (CD skew) must be within an appropriate range.

[Example 1]
H ₃ PO ₄ 70 wt%
+ HNO ₃ 2wt%
CH ₃ COOH 15wt%
C ₃ H ₄ N ₂ (imidazole) 0.1 wt%
H ₂ O 12.9 wt%

  As Example 1, an etching solution composition having the above composition ratio was manufactured, and the etching characteristics were evaluated by the above experimental example.

  FIG. 3 shows a plan view of a Cu / Mo bilayer etched using an etchant containing phosphoric acid, nitric acid, acetic acid, an additive imidazole and water prepared according to Example 1; FIG. 4 is a cross-sectional SEM photograph etched with the etchant composition of Example 1.

  Referring to FIGS. 3 and 4, since the galvanic phenomenon of the Cu / Mo bilayer is reduced and the CD skew and step length are greatly improved, the pattern profile and etching characteristics are improved. It turns out that it is excellent. In other words, comparing FIG. 1 with FIG. 3, it can be seen that when the etching solution of the present invention is used, the step length is significantly improved as compared with the case of using the etching solution of the prior art. Also, comparing FIG. 2 and FIG. 4, it can be seen that the CD skew is greatly improved when the etching solution of the present invention is used, compared with the case where the etching solution of the prior art is used.

  As a result of confirming that the etching characteristics are improved even with an etching solution having another composition ratio, the inventors have found that the etching solution compositions having the composition ratios of the following Examples 2 to 4 are the examples shown in FIGS. The improvement effect was almost similar to the etching characteristics of the etching solution having the composition ratio of 1.

[Example 2]
H ₃ PO ₄ 70 wt%
HNO ₃ 2wt%
CH ₃ COOH 15wt%
_{C 3 H 4 N 2 (imidazole} ) 0.1~0.3wt%
The rest is distilled water

[Example 3]
H ₃ PO ₄ 58 wt%
HNO ₃ 2wt%
CH ₃ COOH 20wt%
_{C 3 H 4 N 2 (imidazole} ) 0.1~0.3wt%
The rest is distilled water

[Example 4]
H ₃ PO ₄ 52 wt%
HNO ₃ 8wt%
CH ₃ COOH 20wt%
_{C 3 H 4 N 2 (imidazole} ) 0.1~0.3wt%
The rest is distilled water

[Etching characteristics depending on the amount of imidazole added]
FIG. 5 shows the change in the etching aspect of the Cu / Mo layer by the addition of imidazole (C ₃ H ₄ N ₂ ) in the etching solution according to this example.

  It can be seen that imidazole is an additive that functions as a Cu / Mo galvanic reaction controller.

  For effective Cu / Mo etching, CD Skew is 0.5 μm or less and the step length generated by the difference in etching rate between Cu and Mo (step length = width of copper-width of molybdenum ( That is, the difference between the copper and molybdenum wiring width after etching)) must be minimized.

  As shown in FIG. 5, it can be seen that there is a concentration at which the step length is minimized by adding imidazole to the phosphoric acid, nitric acid, and acetic acid solutions. FIG. 5 shows that the best effect is obtained when the imidazole concentration is 0.02M.

[Etching characteristics with other additives]
In order to find an additive that reduces the galvanic reaction in addition to imidazole (C ₃ H ₄ N ₂ ), the present inventor, aminotetrazole (CH ₃ N ₅ ), which is a heterocyclic amine compound such as imidazole. Was used as an additive (see FIG. 6). Also, ascorbic acid (C ₆ H ₈ O ₆ ), sodium dihydrogen phosphate (NaH ₂ PO ₄ ), aminoacetoacetic acid (C ₄ H ₇ NO ₄ ), phosphorus Experiments were conducted with a number of additives such as disodium hydrogen phosphate (Na ₂ HPO ₄ ), but the galvanic reaction was reduced from imidazole and CD skew and step length were reduced. At the same time, no significant improvement was found.

For example, FIG. 6 shows changes in the etching characteristics of the Cu / Mo layer due to the addition of aminotetrazole (CH ₃ N ₅ ) belonging to a heterocyclic amine compound such as imidazole. As shown in FIG. 6, it can be seen that aminotetrazole cannot significantly improve the step length over imidazole.

  FIG. 7 shows a comparison between the effect of the step length of imidazole shown in FIG. 5 and the effect of the step length of aminotetrazole shown in FIG. The change of the etching characteristic of Mo layer is shown.

  As described above, according to the study by the present inventors, the fact that imidazole greatly affects the etching rate in the hydrogen peroxide-based etching solution, but does not significantly affect the etching rate in the phosphoric acid-based etching solution. It was.

  The present invention can be applied to patterning of a conductive film used for a TFT of a flat panel display or a touch sensor panel.

Claims (21)

With respect to the total weight of the composition,
50-80 wt% phosphoric acid,
0.5-10 wt% nitric acid,
5-30 wt% acetic acid,
A multi-film etching solution composition comprising 0.01 to 5 wt% imidazole.   The etching liquid composition according to claim 1, wherein the imidazole is contained in an amount of 0.1 to 0.3 wt%. With respect to the total weight of the composition,
50-75 wt% of the phosphoric acid,
1-9 wt% nitric acid in the previous period,
14-20 wt% of acetic acid, and 0.1-0.3 wt% of imidazole
The etching solution composition according to claim 1, wherein the etching solution composition is contained.   The multilayer film includes one or more copper layers of copper or copper alloy, including Cu / Mo laminated metal film, Cu / Mo alloy laminated metal film, Cu alloy / Mo alloy laminated metal film, and one of molybdenum or molybdenum alloy. The etching solution composition according to claim 1, further comprising a molybdenum layer equal to or more than one layer.   The etching solution composition according to claim 4, wherein the multiple film is a Cu / Mo double film.   The etching temperature composition according to claim 1, wherein the operating temperature is 30 ° C. to 60 ° C.   5. The etching solution composition according to claim 4, wherein the thickness ratio of the copper layer to the molybdenum layer is 30: 1 or more.   The etching solution composition according to claim 4, wherein the residual stress of the molybdenum film or the molybdenum alloy film is a tensile stress.   5. The etching solution composition according to claim 4, wherein the copper film or the copper alloy film is annealed at a temperature of 100 ° C. to 300 ° C. for 10 minutes to 1 hour after deposition.   2. The etching solution composition according to claim 1, which does not contain hydrogen peroxide and / or a fluorine compound as a constituent component.   The etching solution composition according to claim 1, which is used for manufacturing a TFT, an active matrix OLED or a touch sensor panel of a flat panel display. Depositing a multilayer film including at least molybdenum or molybdenum alloy film and copper or copper alloy film on a substrate;
Forming a photoresist film having a predetermined pattern on the multiple film;
Using the photoresist film as a mask, 50-80 wt% phosphoric acid, 0.5-10 wt% nitric acid, 5-30 wt% acetic acid, 0.01-5 wt% with respect to the total weight of the composition Etching the multi-layer using an etchant composition comprising 1% imidazole to form metal wiring;
Removing the photoresist film;
Cleaning the metal wiring with deionized water and drying.   The multilayer film includes one or more copper layers of copper or copper alloy and one layer of molybdenum or molybdenum alloy, including a Cu / Mo laminated metal film, a Cu / Mo alloy laminated metal film, and a Cu alloy / Mo alloy laminated metal film. The etching method according to claim 12, comprising the above molybdenum layer.   The molybdenum or molybdenum alloy film is deposited on the substrate, the copper or copper alloy film is deposited on the molybdenum or molybdenum alloy film, and a photoresist film is formed on the copper or copper alloy film. The etching method according to 12.   The etching method according to claim 13, wherein the molybdenum alloy contains molybdenum and at least one element selected from tungsten, titanium, tantalum, and niobium.   The etching method according to claim 13, wherein the copper alloy includes copper and at least one element selected from magnesium, molybdenum, and manganese.   14. The etching method of claim 13, wherein the molybdenum or molybdenum alloy film has a thickness of 100 to 500 angstroms, and the copper or copper alloy film has a thickness of 1000 to 20000 angstroms.   The etching method according to claim 12, wherein the etching is performed at a temperature of 30 ° C. to 60 ° C.   13. The etching method according to claim 12, wherein the etching solution composition is sprayed on the substrate by a spray method (a spray method) for 30 seconds to 150 seconds.   The etching method according to claim 13, wherein the copper or copper alloy film is a source / drain electrode.   The substrate is a glass substrate for a TFT LCD, a metal thin film substrate for a flexible display, or a plastic substrate, and the substrate is used for a TFT LCD, an active matrix OLED, or a touch sensor panel. Etching method.

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