TWI618817B - Etchant composition and etching method using thereof - Google Patents

Abstract

The invention provides an etching solution composition for etching a copper-containing metal layer. The etching solution composition includes hydrogen peroxide, an azole compound, a fluoride ion source, an inorganic acid, and an organic amine compound. The organic amine compound does not include compounds of amino acids and fourth-order ammonium hydroxide, and the acid-base value of the etching solution composition is greater than or equal to 1.5 and less than or equal to 2.5. As a result, the etching solution composition provided by the present invention has excellent copper bearing capacity, which can reduce the amount of the etching solution, reduce the frequency of liquid replacement and the output of waste liquid.

Description

Etching liquid composition and etching method using same

The present invention relates to an etching solution composition, in particular to an etching solution composition for etching a copper-containing metal layer and an etching method using the same.

The wiring materials of small and medium-sized LCDs were mostly aluminum or aluminum alloys. With the development of large-sized panels, displays require lower resistance-capacitance signal delay (RC delay), shorter charging time, and lower aperture ratio. Therefore, copper and its alloys with high conductivity and better resistance to electromigration have been sought for wiring materials.

The manufacturing method of copper-containing wiring is that a copper-containing metal layer is deposited on a substrate, and a photoresist is used as a photomask to determine a required circuit pattern, and then etching is performed by a wet etching method. However, due to the poor adhesion between the silicon-containing layer and the copper of the panel substrate, the copper-containing metal layer may be a single layer containing copper, or a multilayer metal containing copper and other metals, such as copper. / Titanium, copper / nickel, copper / molybdenum and copper / molybdenum nitride. The performance of the aforementioned etching method must meet the following requirements: (1) good cross-sectional shape, and the taper angle of the cross section of copper-containing wiring must be a positive taper angle; (2) less etching metal residue; and (3) copper-containing wiring Distance from photoresist Boundary (critical dimension bias, CD bias) must be greater than or equal to 0.25 microns and less than or equal to 0.75 microns.

However, in addition to meeting the above conditions during the etching process, the copper metal to be etched will be dissolved in the etching solution, and the etching solution is generally used in batches. Therefore, when the copper load reaches the upper limit of use It is necessary to suspend or reduce the production line to drain the entire batch of etching solution and replenish new etching solution to continue production. This will not only cause production line stagnation and cost loss, but a large amount of discharged waste liquid will also increase the environmental burden. .

In view of this, how to further improve the composition of the etching solution and extend the service life of the etching solution on the premise of maintaining the stability of the etching solution is the goal of the industry's efforts.

The present invention aims to provide an etching solution composition having excellent copper bearing capacity, which can reduce the amount of etching solution, reduce the frequency of liquid exchange and reduce the output of waste liquid.

According to an aspect of the present invention, an embodiment is to provide an etching solution composition for etching a copper-containing metal layer. The etching solution composition includes hydrogen peroxide, an azole compound, a fluoride ion source, an inorganic acid, and an organic compound. An amine compound, wherein the organic amine compound does not include compounds of amino acids and fourth-order ammonium hydroxide, and the acid-base value of the etching solution composition is greater than or equal to 1.5 and less than or equal to 2.5.

According to the etching solution composition of the foregoing aspect, it may further include a hydrogen peroxide stabilizer.

According to the etching solution composition of the foregoing aspect, the organic amine compound may be ethylenediamine, diethyltriamine, triethyltetramine, 1,2-propanediamine, 1,3-propanediamine, 1,4 -Butanediamine, cyclopropylamine, dipropylamine, diethylamine, n-butylamine, di-n-butylamine, isobutylamine, diisobutylamine, 1,6-hexanediamine, n-hexylamine or secondary butylamine.

According to the etching solution composition of the foregoing aspect, the organic amine compound may be N-methylethanolamine, N-methyl-diethanolamine, N, N-dimethylethanolamine, ethanolamine, diethanolamine, triethanolamine, 2-amine group 2-methylpropanol, 2-aminobutanol, diethylethanolamine, isopropanolamine, diisopropanolamine, diethylene glycolamine, isobutanolamine, 2-ethylaminoethanol, or 2-ethylaminoethanol Methylaminoethanol.

According to the aforementioned etching solution composition, the inorganic acid may be sulfuric acid, phosphoric acid, or nitric acid.

According to the etching solution composition of the foregoing aspect, the fluoride ion source may be hydrofluoric acid, ammonium fluoride, ammonium hydrogen fluoride, potassium fluoride, potassium hydrogen fluoride, sodium fluoride, sodium hydrogen fluoride, lithium fluoride, hexafluorosilicic acid, four Fluoboric acid or potassium fluoborate.

According to the etching solution composition according to the foregoing aspect, based on the etching solution composition being 100 weight percent, the etching solution composition includes 4 to 10 weight percent hydrogen peroxide, 0.2 to 1 weight percent of azole compounds, and 0.1 A fluoride ion source of weight percent to 0.5 weight percent, an inorganic acid of 3 weight percent to 7 weight percent, and an organic amine compound of 1 weight percent to 7 weight percent. In addition, the etchant composition may further include a hydrogen peroxide stabilizer in an amount of 0.01% by weight to 0.1% by weight.

According to the etching solution composition of the foregoing aspect, the copper bearing capacity of the etching solution composition is greater than or equal to 9000 ppm and less than or equal to 15000ppm.

An embodiment according to another aspect of the present invention is to provide an etching method including contacting a copper-containing metal layer with the aforementioned etching solution composition.

The above summary is intended to provide a simplified summary of the present disclosure so that the reader may have a basic understanding of the present disclosure. This summary is not a comprehensive overview of the disclosure, and it is not intended to indicate important / critical elements of the embodiments of the invention or to define the scope of the invention.

In order to make the above and other objects, features, advantages, and experimental examples of the present invention more comprehensible, the description of the attached drawings is as follows: FIG. 1A shows the etching solution composition according to Embodiment 1 of the present invention at a low copper concentration. Scanning electron microscope image obtained by etching a copper-containing metal layer; FIG. 1B is a scanning electron microscope image obtained by etching the copper-containing metal layer with an etchant composition according to Example 1 of the present invention at a high copper concentration; FIG. 2A is a Scanning electron microscope image of an etchant composition according to Example 2 of the present invention obtained by etching a copper-containing metal layer at a low copper concentration; FIG. 2B is an etching solution composition according to Example 2 of the present invention etched at a high copper concentration Scanning electron microscope image of a copper-containing metal layer; Figure 3A is a scanning electron microscope image of an etchant composition according to Example 3 of the present invention obtained by etching a copper-containing metal layer at a low copper concentration; and Figure 3B is in accordance with Scanning electron microscope image obtained by etching the copper-containing metal layer with the etchant composition of Example 3 of the present invention at a high copper concentration; Figure 4A is a scanning electron microscope image of an etchant composition according to Example 4 of the present invention obtained by etching a copper-containing metal layer at a low copper concentration; and Figure 4B is an etchant composition according to Example 4 of the present invention on Scanning electron microscope image of a copper-containing metal layer etched at high copper concentrations.

Embodiments of the present invention will be discussed in more detail below. However, this embodiment may be an application of various inventive concepts, and may be embodied in various specific ranges. Specific embodiments are for the purpose of illustration only, and are not limited to the scope of the disclosure.

[Etching liquid composition]

The present invention aims to provide an etchant composition for etching a copper-containing metal layer. Specifically, the aforementioned etchant composition can be used to etch a copper-containing single-layer metal, copper / titanium, copper / nickel, copper / molybdenum, Multi-layer metal layers such as copper / molybdenum nitride, molybdenum / copper / molybdenum nitride, molybdenum nitride / copper / molybdenum nitride, and molybdenum nitride / copper / molybdenum.

The etching solution composition includes hydrogen peroxide, an azole compound, a fluoride ion source, an inorganic acid, and an organic amine compound. Among them, hydrogen peroxide, a fluoride ion source, and an inorganic acid can be used to provide an etching ability for a copper-containing metal layer. An azole compound and an organic amine compound are used to improve the stability of the etching solution composition, and make the etching solution composition highly effective. The etching performance can still be maintained under the copper concentration, and for example, azole compounds are used to adjust the side etching ability of the copper-containing metal layer to avoid uneven etching.

In addition, during the etching process, the metal in the layer to be etched will be dissolved. It is dissolved into the etching solution to reduce the service life of the etching solution. At present, the stability of the etching solution is usually improved by adding a chelating agent to the etching solution. However, compounds such as amino acids are often unable to be biodegraded, which leads to wastewater. The chemical oxygen demand (COD) or biochemical oxygen demand (BOD) is too high. Therefore, the etching solution composition of the present invention can improve the service life of the etching solution without containing compounds such as amino acids and fourth-grade ammonium hydroxide to effectively improve the aforementioned problems.

According to the aforementioned etching solution composition, the acid-base value (pH value) is greater than or equal to 1.5 and less than or equal to 2.5, or the acid-base value of the etching solution composition may be 1.5 to 2.4, or the acid-base value of the etching solution composition Values can be from 1.99 to 2.15.

Specifically, based on the etching solution composition being 100 weight percent, the content of hydrogen peroxide may be 4 to 10 weight percent, or the content of hydrogen peroxide may be 5 to 8 weight percent, or hydrogen peroxide. The content may be from 5.1 to 6.9 weight percent. When the content of hydrogen peroxide is less than 4% by weight, the required etching ability cannot be provided. When the content of hydrogen peroxide is more than 10% by weight, the etching rate will be reduced.

In addition, because hydrogen peroxide decomposes and exotherms under high copper concentration, which causes the etch rate to be difficult to control and the temperature rise to catalyze the self-decomposition reaction to cause danger. Therefore, the etchant composition may optionally include, for example, hydrogen peroxide stabilizers, etc. At least one additive to improve the stability of the etchant composition. Specifically, based on the etching solution composition being 100% by weight, the content of the foregoing hydrogen peroxide stabilizer may be 0.01% by weight to 0.1% by weight, and the content of the hydrogen peroxide stabilizer may be preferably 0.02% by weight to 0.04. The weight percentage, that is, the etching solution composition of the present invention is based on all components and the content between them. The combination of the proportions requires only a low amount of hydrogen peroxide stabilizer to obtain an etching solution composition with a lower hydrogen peroxide decomposition rate. In addition, the hydrogen peroxide stabilizer used for etching the copper-containing metal layer may be phenylurea or phenolsulfonic acid and a derivative thereof, but the present invention is not intended to be limited thereto.

The aforementioned fluoride ion source may be hydrofluoric acid, ammonium fluoride, ammonium hydrogen fluoride, potassium fluoride, potassium hydrogen fluoride, sodium fluoride, sodium hydrogen fluoride, lithium fluoride, hexafluorosilicic acid, tetrafluoroborate or potassium fluoroborate. In addition, when the content of the fluoride ion source is too small, the required etching ability will not be provided. However, when the content of the fluoride ion source is too large, the silicon-containing substrate may be damaged. Therefore, based on the etching solution composition, the weight of the fluorine is 100%. The content of ions originating in the etching solution composition may be 0.1% by weight to 0.5% by weight.

The foregoing inorganic acid may be sulfuric acid, phosphoric acid, or nitric acid, and based on the etchant composition, it may be 100% by weight. The content of the foregoing inorganic acid may be 3 to 7% by weight, or the content of the inorganic acid may be 3 to 6% by weight. The percentage, or the content of the inorganic acid may be from 3.5 weight percent to 5.01 weight percent. In addition, the aforementioned acids can be used alone or in combination of two or more kinds. In other words, only one kind of inorganic acid may be used, or two or more kinds may be used simultaneously.

Furthermore, based on the etching solution composition being 100 weight percent, the content of the aforementioned azole compound may be 0.2 weight percent to 1 weight percent, and the azole compound may be triazole, tetrazole, imidazole, indole, purine, pyrazole , Pyridine, pyrimidine, pyrrole, thiazole, pyrrolidine or pyrroline and derivatives thereof. Further, in an acidic environment, the azole compound can control the etching rate of the copper-containing metal layer to avoid the phenomenon of uneven etching, and the azole in the etching solution composition of the present invention The content of the compound-like compound may preferably be increased to 0.4% by weight to 1% by weight to increase the uniformity of etching.

Then, as mentioned above, the organic amine compound is used to improve the stability of the etching solution composition. Therefore, an appropriate amount of the organic amine compound will enable the etching solution composition to maintain the etching performance under high copper concentration. Conversely, when the content of the organic amine compound is too small, it will affect the stability of the composition of the etching solution, resulting in the inability to maintain the etching rate in the later stage of the etching, thereby reducing the production efficiency. Therefore, based on the etching solution composition being 100 weight percent, the content of the aforementioned organic amine compound may be 1 weight percent to 7 weight percent, or the content of the organic amine compound may be 1 weight percent to 5 weight percent, or The content may be from 1.7 weight percent to 4 weight percent. And based on the use of the aforementioned azole compounds, the aforementioned organic amine compound may be any one or more of a combination of fatty amine compounds, alcohol amine compounds, or other organic amines, that is, only one kind of organic amine compound may be used, or they may be used simultaneously. More than two. It should be noted that, in order to avoid increasing the service life of the etching solution composition and causing a burden on the environment, the aforementioned organic amine compounds do not include amino acids and fourth-grade ammonium hydroxide compounds.

Specifically, when the aforementioned organic amine compound is an aliphatic amine compound, it may be ethylenediamine, diethyltriamine, triethyltetramine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, cyclopropylamine, dipropylamine, diethylamine, n-butylamine, di-n-butylamine, isobutylamine, diisobutylamine, 1,6-hexanediamine, n-hexylamine, or secondary butylamine amine. When the organic amine compound is an alcohol amine compound, it may be N-methylethanolamine, N-methyl-diethanolamine, N, N-dimethylethanolamine, ethanolamine, diethanolamine, triethanolamine, 2-amino group- 2-methylpropanol, 2-aminobutane Alcohol, diethylethanolamine, isopropanolamine, diisopropanolamine, diethylene glycolamine, isobutanolamine, 2-ethylaminoethanol or 2-methylaminoethanol.

In addition, the etching solution composition uses water as a solvent, and the water may be, but is not limited to, distilled water, deionized water, and preferably deionized water. In addition, the content of water will change with the sum of the contents of other components in the etchant composition. In the presence of other ingredients, water is added to make the content of the etchant composition 100% by weight. In other words, hydrogen peroxide, The total content of the azole compound, the fluoride ion source, the inorganic acid, the organic amine compound, water, and the additives that may be contained is 100% by weight.

Therefore, the aforementioned etching solution composition can make the CD difference of the copper-containing wiring fall within an acceptable range of 0.25 μm or more and 0.75 μm or less within the over etching rate range required by the actual production line. And can maintain the etching performance from low copper concentration to high copper concentration. In particular, based on the combination of the foregoing components and their proportions, the copper bearing capacity of the etching solution composition of the present invention can be increased to 9000 ppm to 15000 ppm.

It is added that the aforementioned “high copper concentration” means that the copper ion concentration is greater than 6000 ppm, and the aforementioned “late etching” means that after the etching solution composition is used for etching (usually after multiple etchings), the copper ion concentration is greater than 6000ppm period. In contrast, "low copper concentration" means that the copper ion concentration is greater than or equal to 0 and less than or equal to 6000 ppm.

[Etching method]

An etching method includes contacting a copper-containing metal layer with the aforementioned etching solution composition, wherein the copper-containing metal layer may be a copper-containing single layer metal or a copper-containing metal layer. The details of multi-layer metals (such as copper / titanium) have been described above, and will not be repeated here.

According to the above embodiments, specific examples are provided below to describe the etching solution composition of the present invention and its achievable effects in detail.

[Example]

First, the etchant compositions of Examples 1 to 4 were prepared. The acid-base values of the etching solution compositions of Examples 1 to 4 are shown in Table 1, and the components of the etching solution compositions of Examples 1 to 4 are shown in Table 2.

Next, a 500 Angstrom (Å) titanium layer and a 3,000 Angstrom copper layer were successively deposited on the glass substrate to form a copper / titanium double-layer metal layer, and then the foregoing double layer was deposited A photoresist is coated on the glass substrate of the metal layer, and exposed and developed to form a photomask. Subsequently, the foregoing two-layer metal layer is etched with the etching solution compositions of Examples 1 to 4 at an etching temperature of 30 ° C to 35 ° C, respectively. At this time, the etching performance of Examples 1 to 4 is shown in Table 3 below.

In Table 3, the total etching time refers to the time taken from the beginning of etching to the end of etching. The etching angle (that is, the aforementioned taper angle, Taper), CD difference, and chamfering are observed using a scanning electron microscope image on the glass substrate on which the aforementioned two-layer metal layer is deposited, respectively, after being etched through the etchant composition of Examples 1 to 4 Section view. Wherein, the angle of the cross-section of the double-layer metal layer obtained by cutting the glass substrate on which the double-layer metal layer is deposited is measured, and the angle is the etching angle. The chamfer is to measure the angle between the bottom of the cross section of the double-layer metal layer and the glass substrate. If it is greater than 90 degrees, it is judged as a chamfer and evaluated as "×". If no chamfer occurs, it is evaluated as "○". As for the CD difference, the horizontal distance from the end of the photoresist to the end of the bottom of the double-layer metal layer is measured.

In addition, as described above, the low copper concentration refers to the copper ion concentration in the etchant composition during the first etching, and the copper ion content of the etchant composition before the etching is about 0 ppm. As for the high copper concentration, it refers to the copper ion concentration contained in the etching solution composition after performing multiple etchings, and here refers to the maximum copper carrying capacity of each embodiment, for example, the amount measured at high copper concentration in Example 1 The measured etch angle and CD difference refer to the etching performance when the double-layer metal layer is etched by using an etching solution composition containing a copper ion concentration of about 9000 ppm.

Please refer to Table 3 and Figures 1A to 4B together. Figures 1A and 1B are obtained by etching the copper-containing metal layer at a low copper concentration and a high copper concentration, respectively, according to the etchant composition of Embodiment 1 of the present invention. The scanning electron microscope image, FIG. 2A and FIG. 2B are respectively a scanning electron microscope image obtained by etching the copper-containing metal layer at a low copper concentration and a high copper concentration according to the etching solution composition according to Example 2 of the present invention. 3A and 3B are scanning electron microscope images obtained by etching the copper-containing metal layer at low and high copper concentrations according to the etching solution composition according to Example 3 of the present invention, and FIGS. 4A and 4B are respectively Scanning electron microscope image of an etchant composition according to Example 4 of the present invention obtained by etching a copper-containing metal layer at a low copper concentration and a high copper concentration.

First, as shown in Table 3 and FIG. 1A to FIG. 1B, the copper / titanium double-layer metal layer is etched using the etchant composition according to Example 1 of the present invention, wherein the organic amine compound in the etchant composition of Example 1 is used. Is an alcohol amine compound, and the organic amine compound is specifically isopropanolamine. In addition, the azole compound in Example 1 is 5-aminotetrazole. At this time, it can be known from Table 3 that the CD differences at low copper concentration and high copper concentration are 0.41 μm and 0.67 μm, respectively, and both fall within the standard range of 0.25 μm to 0.75 μm. In addition, the etching angle at low copper concentration is 53 degrees and the etching angle at high copper concentration is 42 degrees, which also falls within the standard range of 30 degrees to 60 degrees. It is known from FIG. 1A and FIG. 1B that there is no chamfer when the copper / titanium double-layer metal layer is etched with the etching solution composition of Example 1 of the present invention at a low copper concentration and a high copper concentration. , All are evaluated as "○".

Next, as shown in Table 3 and FIG. 2A to FIG. 4B, the copper / titanium double-layer metal layer is etched using the etching solution composition according to Embodiments 2 to 4 of the present invention, respectively, in which Examples 2 to 4 The organic amine compound in the etchant composition is a fatty amine compound, and is specifically ethylenediamine. In addition, the azole compound in Example 2 is also 5-aminotetrazole. At this time, it can be known from Table 3 that the CD difference between the low copper concentration and the high copper concentration of Examples 2 to 4 falls within the standard range of 0.25 μm to 0.75 μm. In addition, the etching angles of Examples 2 to 4 at low copper concentrations are 48 degrees, 35 degrees, and 36 degrees, respectively, and the etching angles at high copper concentrations are 45 degrees, 43 degrees, and 45 degrees, respectively. It falls within the standard range of 30 degrees to 60 degrees. In addition, from FIGS. 2A to 4B, it is known that the etching solution composition of Examples 2 to 4 does not have a chamfer when etching the copper / titanium double-layer metal layer at a low copper concentration and a high copper concentration, that is, Both were evaluated as "○".

It can be seen that even if the copper ion concentration contained in the etching solution composition of Example 4 has reached 15,000 ppm, its etching performance (CD difference of 0.72 micrometers and etching angle of 45 degrees) can be maintained within the standard range, that is, this The maximum copper carrying capacity of the etchant composition of Invention Example 4 can reach 15000 ppm. Similarly, the maximum copper carrying capacity of the etching solution compositions of Examples 2 and 3 can also reach 9000 ppm.

Accordingly, the etching solution composition provided by the present invention simultaneously contains hydrogen peroxide, azole compounds, fluoride ion sources, inorganic acids, and organic amine compounds, so that it can maintain good performance even at a high copper concentration of 9000ppm to 15000ppm. The etching performance of the etching solution composition of the present invention has excellent copper bearing capacity and long service life, which can reduce the amount of etching solution, reduce the frequency of liquid exchange and waste liquid output, and meet the current environmental protection requirements. demand.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and retouches without departing from the spirit and scope of the present invention. Therefore, the protection of the present invention The scope shall be determined by the scope of the attached patent application.

Claims (9)

An etching solution composition is used to etch a copper-containing metal layer. The etching solution composition comprises: 4 weight percent to 10 weight percent hydrogen peroxide; 0.2 weight percent to 1 weight percent of azole compounds; 0.1 weight percent to 0.5 weight percent of a fluoride ion source; 3 weight percent to 7 weight percent of an inorganic acid; and 1 weight percent to 7 weight percent of an organic amine compound, wherein the organic amine compound does not include amino acids or fourth-order ammonium hydroxide And the acid-base value of the etching solution composition is greater than or equal to 1.5 and less than 2.5. The etching solution composition described in item 1 of the scope of patent application, further comprises a hydrogen peroxide stabilizer. The etching solution composition according to item 1 of the patent application scope, wherein the organic amine compound is ethylenediamine, diethyltriamine, triethyltetramine, 1,2-propanediamine, 1,3-propane Diamine, 1,4-butanediamine, cyclopropylamine, dipropylamine, diethylamine, n-butylamine, di-n-butylamine, isobutylamine, diisobutylamine, 1,6-hexanediamine, n-hexylamine or Secondary butylamine. The etching solution composition according to item 1 of the scope of the patent application, wherein the organic amine compound is N-methylethanolamine, N-methyl-diethanolamine, N, N-dimethylethanolamine, ethanolamine, diethanolamine, triethanolamine Ethanolamine, 2-amino-2-methylpropanol, 2-aminobutanol, diethylethanolamine, isopropanol Amine, diisopropanolamine, diethylene glycol amine, isobutanolamine, 2-ethylaminoethanol or 2-methylaminoethanol. The etching solution composition according to item 1 of the patent application scope, wherein the inorganic acid is sulfuric acid, phosphoric acid or nitric acid. The etching solution composition according to item 1 of the scope of the patent application, wherein the fluoride ion source is hydrofluoric acid, ammonium fluoride, ammonium hydrogen fluoride, potassium fluoride, potassium hydrogen fluoride, sodium fluoride, sodium hydrogen fluoride, lithium fluoride, Hexafluorosilicic acid, tetrafluoroboric acid or potassium fluoborate. The etching solution composition according to item 1 of the scope of the patent application, wherein the etching solution composition is based on 100% by weight, and the etching solution composition further comprises: 0.01% by weight to 0.1% by weight of the hydrogen peroxide stabilizer. The etching solution composition according to item 1 of the scope of the patent application, wherein the copper bearing capacity of the etching solution composition is greater than or equal to 9000 ppm and less than or equal to 15000 ppm. An etching method includes: contacting a copper-containing metal layer with the etchant composition as described in any one of claims 1 to 7 of the scope of patent application.