TW201831726A - Etchant composition for metal wire comprising an oxidizing agent, a bivalent alcohol compound, an azole-based compound containing no amino group and water - Google Patents

Abstract

The invention discloses a metal wire etchant composition for etching a metal film to form a gate and a source / drain region of a thin film transistor constituting a semiconductor circuit. The metal wire etching solution composition includes an oxidizing agent, a glycol compound, an azole compound not containing an amino group, and water.

Description

Metal wire etchant composition

The present invention relates to a metal wire etchant composition, and more particularly, to a metal wire etchant composition that etches a metal film to form a gate and a source / drain region of a thin film transistor constituting a semiconductor circuit.

In the field of display industry such as liquid crystal display (LCD), it is necessary to improve the response speed of the liquid crystal display (LCD) screen in response to the high-quality, high-quality and large-area screens. To this end, the gate and source drain (S / D) regions of thin film transistors (TFTs) that make up the semiconductor circuits of the display are made of non-conventional chromium, aluminum, and An alloy is a copper metal with lower resistance, and the method of increasing the channel formation speed between the source / drain when the gate electrode operates. In addition, in order to improve the adhesion between the copper metal film and the lower glass substrate or silicon insulating film, and to suppress copper diffusion to the silicon film, titanium (Ti), molybdenum (Mo), and titanium alloy are mixed in the lower portion of the copper metal film. (Ti-alloy), molybdenum alloy (Mo-alloy) and other intermediate metal films, thereby having the following advantages: according to the thickness of the above intermediate metal film can change the moving speed of electrons, and can control the moving speed of electrons. In addition, the residue of the intermediate metal film needs to be removed, and in the subsequent module technology, the driving failure caused by the short circuit of the line can be blocked. The etching solution composition for forming a metal line by etching the above-mentioned metal film has an excellent etched cross section of the metal line to be etched in order to maximize the profit of the process, and the number of substrates to be processed (competitiveness) is large. Therefore, there is a need for a composition that can satisfy the above-mentioned conditions and has an excellent yield (3,000 ppm) compared to conventional products.

Technical problem to be solved by invention

Therefore, an object of the present invention is to provide a metal wire etchant composition having an excellent etching profile. Another object of the present invention is to provide a metal wire etchant composition having an improved number of substrates (over time).

Technical solution to the problem

In order to achieve the above object, the present invention provides a metal wire etching solution composition, including: an oxidizing agent, an amine compound, a glycol compound, an azole compound not containing an amino group, and water.

In addition, the present invention provides a metal wire etching solution composition including: an oxidant, a diol compound, an azole compound not containing an amino group, an amine compound, and one or more members selected from the group consisting of a sulfate compound, a fluorine-based compound and a mixture thereof The compounds in the group consist of etchant and water.

Effect of the invention

The metal wire etchant composition of the present invention can obtain a faster etching process when forming a copper metal film circuit that selectively etches copper / molybdenum or titanium and copper alloy / molybdenum alloy double-layer films and multilayer films. And excellent taper etched profile. In addition, in order to improve the competitiveness of the etching solution, the etching solution is stabilized from copper ions, and the production yield is improved.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

The metal wire etchant composition according to the present invention is an etching copper (Cu), titanium (Ti), molybdenum (Mo), copper alloy (Cu-alloy), titanium alloy (Ti-alloy), and molybdenum alloy (Mo-alloy ) And other metal films that form semiconductor circuits, such as gate electrode and source / drain electrode compositions that form thin-film transistors, including oxidants, amine compounds, glycol compounds, and azoles that do not contain amino groups Compounds and water.

The role of the oxidant is to oxidize the metal film. Preferably, hydrogen peroxide (H ₂ O ₂ ) can be used. For example, the metal film containing copper (Cu) is oxidized and etched according to the following reaction formula 1, and, according to In the following reaction formula 2, a hydrogen peroxide decomposition reaction occurs. The content of the oxidant (hydrogen peroxide) is 5 to 25% by weight, preferably 10 to 25% by weight, and more preferably 20 to 25% by weight for the entire etchant composition. An etching rate to be obtained can be obtained within the content range of the oxidizing agent, and an excessive amount of etching can be prevented, and the copper metal film can be etched by an appropriate amount.

[Reaction formula 1]

M + H₂ O₂ → MO + H₂ O

[Reaction formula 2]

H₂ O₂ + M⁺ → ․ OH + OH^- + M²⁺

In the reaction formulae 1 and 2, M is a metal film such as copper, titanium, molybdenum, copper alloy, titanium alloy, and molybdenum alloy.

The role of the amine compound is to perform ligand binding (coordination binding with metal ions) with divalent copper ions during copper metal etching, and chelate the copper ions to stabilize the copper ions and improve etching. Ability to increase the number of sheets processed. The amine compound is, for example, a water-soluble ligand, succinic acid, succinimide, Iminodiacetic acid, Iminodisuccinic acid, or Mixtures thereof and the like are preferably exemplified by iminodiacetic acid. The content of the amine compound is 0.01 to 5% by weight, preferably 0.1 to 3% by weight, and more preferably 2 to 3% by weight for the entire etching solution. When the content of the amine compound is within the above range, copper ions can be stabilized and the etching ability can be improved.

The glycol compound functions as a stabilizer that stabilizes the oxidant (hydrogen peroxide) in the etching solution, thereby extending the life of the chemical solution. For example, it can extend the contamination concentration of the conventional alkali metal to 3,000 to 4,000 ppm to 7,000ppm. Briefly explain the mechanism of the glycol compound. As the number of treatments increases, the concentration of metal pollution increases proportionally. The free radical decomposition of hydrogen peroxide occurs due to alkali metals (such as Cu ^2+, etc.). The existence of excess metal causes continuous reaction with hydrogen peroxide to decompose, which becomes the cause of rapid decomposition of hydrogen peroxide, and becomes a dangerous factor such as heat generation and explosion. Therefore, a glycol compound is used even if the alkali metal excess exists It can also be electrostatically stabilized to prevent reaction with hydrogen peroxide and improve the yield of the production process. In addition, the diol compound has a small influence on the etching characteristics of EPD (End point detect), CD-Bias, and Taper angle. Therefore, it can be used. If a monohydric alcohol or trihydric alcohol is used, the Etching characteristics have an effect, that is, they have large variability, and are difficult to use.

The glycol compound is an ethylene glycol compound, preferably, ethylene glycol (1,2-ethanediol), diethylene glycol (diethyleneglycol), propane-1,2-diol (propane-1,2-diol) diol), Triethyleneglycol, Trimethyleneglycol, 1,3-propanediol, Propylene Glycol, 1,4-butanediol, 1,5- Pentylene glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, pinacol, hydrogenated benzene Marriage, benzyl pinacol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol or a mixture thereof, etc., more preferably, Diethylene glycol (DEG). The content of the glycol compound is 0.1 to 10% by weight, preferably 1 to 7% by weight, and more preferably 1 to 5% by weight for the entire etching solution. When the content of the glycol compound exceeds the range, the effect of improving the yield of the production process cannot be obtained.

The role of azole compounds (cyclic amine compounds) that do not include the amino group is to adjust the copper and other metals (such as , Titanium, molybdenum, titanium alloy, molybdenum alloy, etc.). In addition, the azole-based compound can reduce the cut dimension loss (CD loss) of a metal wire formed by etching, so that the formed metal wire can be usefully used as a gate electrode and a data line. The azole compound is a 5-membered heterocyclic ring compound containing a nitrogen atom, for example, 5-methyltetrazole_MTZ, benzotriazole, imidazole, imidazole, Pyrazole, tolytriazole, or a mixture thereof, and the like are preferably methyltetrazole. The azole compound does not include an amino group. If an azole compound contains an amino group, it is decomposed by a reaction with metal ions (Cu ^2+, etc.), and the life as an etching inhibitor is shortened or destabilized. Therefore, the azole compound does not contain an amino group. Since the metal ions do not react, the life as an etching inhibitor can be extended and the stability is excellent.

The content of the azole compound that does not include the amino group is 0.03 to 1.5% by weight, preferably 0.05 to 1.2% by weight, and more preferably 0.08 to 0.7% by weight based on the entire etching solution. If the content of the azole-based compound that does not include the amino group is within the above range, it is possible to obtain an appropriate etching rate and excellent line straightness. In addition, if the content is too small, the copper etching rate cannot be adjusted, excessive etching occurs, or CD loss is increased, and the straightness of the line is reduced. Therefore, it may cause deep problems when applied to mass production processes. And may make the etched cross section of the formed metal line poor, and if it is included too much, the etching speed will be lowered and the time of the etching technology will be prolonged.

The remaining content of the water is such that the total weight of the etching solution becomes 100%.

The metal wire etchant composition may further include an etchant including one or more compounds selected from the group consisting of a sulfate compound, a fluorine-based compound, and a mixture thereof.

The etchant is an auxiliary oxidant for the copper metal film, and has the effect of adjusting the etching speed of copper, or the barrier film of the metal film, that is, titanium, molybdenum, titanium alloy, and molybdenum alloy. The function of forming the taper angle in the film includes more than one sulfate compound, fluorine-based compound, and mixtures thereof, and preferably includes both sulfate compound and fluorine-based compound.

The sulfate compound is an auxiliary oxidant for the copper metal film, and has the effect of adjusting the etching speed of copper. For example, the sulfate compound is sodium sulfate, potassium sulfate, ammonium sulfate, and sodium persulfate ( sodium persulfate, potassium persulfate, ammonium persulfate, ammonium nitrate, benzenesulfonic acid, p-toluenesulfonate, ammonium sulfate acid), amidosulfonic acid, methanesulfonic acid, cyclic sulfonic acid, a hydrocarbon sulfonic acid compound, and the like, preferably methanesulfonic acid.

The role of the fluorine-based compound is to form a taper angle in a double-layer film or a multilayer film when etching a barrier film of a metal film, that is, titanium, molybdenum, titanium alloy, or molybdenum alloy. Specific examples of the fluorine-based compound are hydrofluoric acid (KF), sodium fluoride (NaF), ammonium fluoride (NH ₄ F), ammonium hydrogen fluoride (NH ₄ HF ₂ ), and fluorosilicic acid (H ₂ SiF ₆ ), fluoroboric acid (HBF ₄ ), fluorotitanic acid (H ₂ TiF ₆ ), fluorozirconic acid (H ₂ ZrF ₆ ), or a mixture thereof, etc., preferably ammonium hydrogen fluoride (NH ₄ HF ₂ ).

The content of the etchant is 0.01 to 5% by weight, preferably 0.5 to 3% by weight, and more preferably 1 to 2% by weight for the entire etchant composition. If the content of the etchant exceeds the range, the efficiency as an etchant may be reduced.

More preferably, the content of the sulfate compound is 0.01 to 5% by weight, preferably 0.5 to 3% by weight, and more preferably 1 to 2% by weight for the entire etchant composition. If the content of the sulfate compound is too small, it is difficult to etch the copper film. If it is within the range, the etching speed of the copper film can be made faster, and the adjustment on the manufacturing process is easy. In addition, the content of the fluorine-based compound is 0.01 to 1% by weight, preferably 0.05 to 0.2% by weight, and more preferably 0.07 to 0.15% by weight for the entire etchant composition. If the content of the fluorine-based compound is too small, the etching speed of the barrier film is reduced, the taper angle is poor, and the residual film of the lower film is defective. If the content is too high, the glass film under the metal film is etched or blocked. The film was over-etched.

As the etchant composition of the present invention, the remaining component is water, and preferably, deionized water (DI), distilled water, and the like. According to the etching solution composition of the present invention, if necessary, a general additive such as a pH adjuster, a preservative, and the like can be further included within a range in which the objects and effects of the present invention are achieved. The etchant composition according to the present invention can be produced by any conventional method. For example, the diol compound, azole compounds, amine compounds, sulfate compounds, and fluoro-based compounds that do not include an amino group are added to an aqueous medium such as deionized water and distilled water at a desired concentration, and then the desired The above-mentioned hydrogen peroxide is added to produce a composition of the present invention.

According to the etchant composition of the present invention, the gate electrode and the source / drain electrode (two types) can be uniformly etched, and the number of processing sheets can be doubled compared with the conventional method, thereby increasing the production yield and being applicable to the aperture ratio. Increased high resolution. In addition, the variation in taper is low, and it is possible to minimize the stack failure of the TFT-composite film.

The etchant composition according to the present invention is suitable for etching a metal film to form a metal line of a semiconductor circuit. The metal film etched by the composition of the present invention includes a single metal film including copper (Cu), an alloy film including a copper alloy film, and a copper film including an upper film. As the lower film, at least one titanium film may be included. , Multilayer films such as titanium alloy films, molybdenum films, and molybdenum alloy films. In addition, when the multilayer film is etched, the upper film and the lower film may be uniformly or selectively etched.

According to the metal wire forming method of the present invention, as a method for manufacturing integrated circuits such as a semiconductor, a multilayer of the copper single film or copper / titanium, copper / molybdenum, copper / titanium alloy, and / or copper / molybdenum alloy is formed on a substrate. A metal film such as a film, and a photoresist pattern is formed on the metal film. Then, the photoresist pattern is used as a mask, and the metal film is etched by contacting the etchant composition of the present invention on the metal film, thereby forming a metal line such as a gate electrode or a source / Drain electrode.

Hereinafter, the present invention will be described in more detail through examples, but the present invention is not limited to the following examples.

[Examples 1 to 8 and Comparative Examples 1 to 13] Production of etching solution composition

In order to evaluate the etching performance of the etchant composition, an etchant composition (Examples 1 to 8 and Comparative Examples 1 to 13) including the compounds shown in Table 1 below and deionized water were manufactured. Here, hydrogen peroxide means hydrogen peroxide, IDA means iminodiacetic acid, ABF means ammonium fluoride, DEG means diethylene glycol, MTZ means 5-methyltetrazole, and ATZ means 5- Aminotetrazole.

【Table 1】

[Experimental Example 1] Evaluation of Etching Solution Composition

A photoresist pattern was formed on a copper / molybdenum and copper / molybdenum alloy double-layer film, and the end point detection was performed by using the etchant compositions of Examples 1 to 8 and Comparative Examples 1 to 13 to etch from a vertical section (EPD: End Point Detection), and based on this, over etching was performed. The cross section of the etched metal film was observed with a scanning electron microscope, and the etching rate, the range of the lateral CD change, the taper change range, and the number of processed sheets are shown in Table 2 below. Here, the range value is a competitive judgment standard, the number of treatments of the chemical solution is judged, and the production yield is improved. Moreover, the CD skew (critical dimension skew) refers to the end of the photoresist pattern and the lower film or barrier. The distance between the ends of the film, in order to make the step less, and uniformly tapered etching, to form a side of 0.5 to 0.8 µm. In addition, the taper angle is an inclination viewed from the side of the etched metal film, and 45 to 60 ° is suitable. Here, ◎ means "very good" (etching speed: 170 ~ 180Å / sec / CD change range: side deviation ≤0.1µm / Taper change range: ≤5˚ / number of sheets processed: ≥7000ppm), ○ means " "Good" (etching speed: 160 ~ 169Å / sec / CD change range: 0.11 ~ 0.20 µm / Taper change range: 6˚ ~ 9˚ / number of sheets: 4000 ~ 5000ppm), △ means "bad" (etching Speed: ≤159Å / secor≥181Å / sec / CD change range: side deviation ≥0.20 µm / Taper change range: ≥10˚ / number of sheets processed: ≤3000ppm).

【Table 2】

Fig. 1 is a scanning electron microscope image of a cross section measured after etching. FIG. 1 is a benchmark for evaluation of Examples and Comparative Examples. As shown in Table 2, it can be seen that Comparative Example 1 which does not contain hydrogen peroxide has an etching rate, off-side CD, taper angle, and The number of treated sheets was poor, and Comparative Example 9 in which an azole compound containing an amino group was used, compared with Examples 1 to 8 in which an azole compound not containing an amino group was used, the taper angle and the number of treated sheets were poor, and it was found that An azole compound containing an amino group affects the etching rate, the taper angle, and the number of sheets to be processed.

Further, using Comparative Example 4 in which an azole-based compound not containing an amino group and a low content of an amine-based compound (IDA) were used, not only the taper angle and the number of sheets to be treated were poor, but also the side CD was not good. In Comparative Example 11, which has an effect on the side, and uses a triol compound instead of the diol compound, except for the side CD of the etching rate, the taper angle, and the number of processed sheets are bad.

In addition, if Examples 6 and 7 include a fluorine-based compound or a sulfate-based compound, the side, taper angle, and number of sheets are excellent. However, Example 8 including a fluorine-based compound and a sulfate compound is also different. Side CD, taper angle, and number of sheets are very good. Comparative Example 4 without amine compounds and Comparative Example 5 without diols have good etching rates, but other characteristics are poor, including azoles containing amino groups. Comparative Example 9 of the compound exhibited poor etching rate. From this, it can be understood that when the etching solution composition of the present invention is used, the etching rate, the side CD, the taper angle, and the number of processed sheets are excellent. In particular, the number of processed sheets is excellent, and the life of the chemical solution is prolonged compared with the past.

In addition, in Comparative Example 3 using an ammonium sulfate etchant exceeding the numerical limitation range, the etching speed, side CD, taper range, and number of treatments were all good levels, but local erosion caused by overetching occurred, and the etchant was required. The numerical range was not more than 5%, and Comparative Example 6 using a diol exceeding the numerically limited range showed poor yield.

In addition, Comparative Example 12 using hydrogen peroxide smaller than the numerically limited range not only had poor etching speed, but also poor lateral CD, taper angle, and number of sheets. Comparative Example 13 using an azole compound containing an amino group was less than the numerically limited range. , Etching speed, off-side CD, number of sheets processed are bad.

no

FIG. 1 is a scanning electron microscope image for measuring a cross section after etching.

Claims (12)

A metal wire etchant composition includes: an oxidant; an amine compound; a glycol compound; an azole compound not containing an amino group; and water. The metal wire etchant composition according to item 1 of the patent application scope, wherein the oxidant is hydrogen peroxide. The metal wire etchant composition according to item 1 of the scope of the patent application, wherein the amine compound is selected from the group consisting of succinic acid, succinimine, iminodiacetic acid, iminodisuccinic acid, and mixtures thereof. . The metal wire etchant composition according to item 1 of the scope of the patent application, wherein the glycol compound is selected from the group consisting of ethylene glycol, diethylene glycol, propane-1,2-diol, triethylene glycol, 1,2- Propylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, pinacol, hydrogenated benzoin, phenylpinacol, cyclopentane-1,2-diol, cyclohexane-1,2-di A group of alcohols, cyclohexane-1,4-diols, and mixtures thereof. The metal wire etchant composition according to item 1 of the scope of the patent application, wherein the azole compound not containing the amino group is selected from the group consisting of methyltetrazole, benzotriazole, imidazole, pyrazole, and methylbenzotriazine. A group of azoles and mixtures thereof. The metal wire etchant composition according to item 1 of the scope of the patent application, wherein the metal wire etchant composition further comprises: an etchant comprising one or more selected from the group consisting of a sulfate compound, a fluorine-based compound, and a mixture thereof. Compounds in the group. The metal wire etchant composition according to item 6 of the scope of the patent application, wherein the sulfate compound is selected from the group consisting of sodium sulfate, potassium sulfate, sodium persulfate, potassium persulfate, ammonium persulfate, ammonium sulfate, ammonium nitrate, and benzene. A group of sulfonic acid, p-toluenesulfonic acid, ammonium sulfate, sulfonamidic acid, methanesulfonic acid, cyclic sulfonic acid compounds, hydrocarbon sulfonic acid compounds, and mixtures thereof. The metal wire etchant composition according to item 6 of the scope of the patent application, wherein the fluorine-based compound is selected from the group consisting of KF, NaF, NH ₄ F, NH ₄ HF ₂ , H ₂ SiF ₆ , HBF ₄ , H ₂ TiF ₆ , Group consisting of H ₂ ZrF ₆ and mixtures thereof. A metal wire etchant composition includes: an oxidant; a glycol compound; an azole compound not containing an amino group; an amine compound; an etchant, including one or more selected from the group consisting of a sulfate compound, a fluorine-based compound, and a mixture thereof A group of compounds; and water. The metal wire etchant composition according to item 9 of the scope of the patent application, wherein the content of the oxidant is 1 to 25% by weight, the content of the glycol compound is 0.1 to 10% by weight, and the The content is 0.03 to 1% by weight, the content of the amine compound is 0.01 to 5% by weight, the content of the etchant is 0.01 to 5% by weight, and the remaining content is water. The metal wire etchant composition according to item 1 of the scope of patent application, wherein the metal circuit is made of copper (Cu), titanium (Ti), molybdenum (Mo), copper alloy (Cu-alloy), titanium alloy (Ti- alloy) and mo-alloy. The metal wire etchant composition as described in any one of claims 1 to 11, wherein the metal wire includes a single metal film including copper, an alloy film including a copper alloy film, and a copper film of an upper film, The lower film is selected from the group consisting of a multilayer film selected from the group consisting of titanium, a titanium alloy, molybdenum, and a molybdenum alloy.