KR20110027370A - Etching solution composition for formation of cu line - Google Patents

Abstract

PURPOSE: An etching solution composition is provided to minimize the damage of a substrate and a lower insulating layer and residue generation by obtaining excellent etching profile in a multi-layered film containing a copper-based metal film and a titanium-based metal film. CONSTITUTION: An etching solution composition for a multi-layered film containing a copper-based metal film and a titanium-based metal film comprises, based on the total weight of the composition, 0.1~5 weight% of inorganic salt oxidants, 0.1~5 weight% of chlorine-containing compounds, 0.01~2 weight% of fluorine-containing compounds, 0.1~10 weight% of water-soluble compounds with an amino group and a carboxy group, and the remaining amount of water.

Description

Etching liquid composition for formation of copper wiring {ETCHING SOLUTION COMPOSITION FOR FORMATION OF CU LINE}

The present invention relates to a wet etchant composition for a multilayer including a copper-based metal film and a titanium-based metal film.

In general, the process of forming metal wiring on a substrate in a semiconductor device and a flat panel display device is performed by a metal film forming process by sputtering, a photoresist forming process and an etching process for a selective region by photoresist coating, exposure and development. It consists of the steps, and the washing process before and after an individual unit process, etc. are included.

The etching process refers to a process of leaving a metal film in a selective region using a photoresist mask, and typically, dry etching using plasma or wet etching using an etching solution is used.

In recent years, the resistance of metal wiring has emerged as a major concern in semiconductor devices and flat panel display devices. Since resistance is a major factor causing RC signal delay, it is very important for increasing panel size and high resolution in flat panel displays.

In order to reduce the RC signal delay required for flat panel display devices, it is necessary to develop low-resistance materials, and chromium (Cr resistivity: 12.7 × 10 ^-8 Ωm) and molybdenum (Mo resistivity: 5 × 10 ^-8 Ωm), aluminum (Al resistivity: 2.65 × 10 ^-8 Ωm) and alloys thereof are difficult to use as gates and data wirings used in large TFT LCDs.

Under such a background, there is a high interest in a copper film, which is one of the new low resistance metal films. This is because the copper film is known to have an advantage that the resistance is significantly lower than that of the aluminum film or the chromium film and that there is no big problem in the environment. However, the copper film has many disadvantages in the process of applying and patterning the photoresist, and the disadvantages of poor adhesion to the silicon insulating film have been found.

Accordingly, researches on multiple metal films that compensate for the shortcomings of the low-resistance copper single layer have been in progress, and among them, a material which is particularly in the limelight is a copper-titanium film. As an etchant for such a copper-titanium film, an etchant described in Korean Laid-Open Patent Publication No. 2001-11390 is known. That is, the patent document includes a step of sequentially depositing a copper film and a titanium film on a substrate and simultaneously forming a gate electrode by simultaneously etching a copper film as a first gate metal and a titanium film as a second gate metal according to a predetermined pattern. A method of forming a gate electrode of a thin film transistor and a mixed etchant of HF, HNO ₃ and CH ₃ COOH used in such an etching process are disclosed.

However, in the case of using an etching solution in which the etching solution for the copper film and the etching solution for the titanium film are simply mixed with the etching solution of the copper-titanium film as described above, the etching profile is poor, and subsequent steps are difficult. Fluorine ions (F ⁻ ), which are used to etch titanium films, damage glass substrates and silicon layers, making them unsuitable for practical use in the process.

In addition, although hydrogen peroxide, which is a conventional copper etching solution, is excellent in etching profile, number of etching, and time-lapse, a risk problem due to instability of hydrogen peroxide itself is not yet solved, and thus there is a shortage as an etching solution.

The present invention is to solve the above problems of the prior art, to provide an excellent etching profile for a multi-layer including a copper-based metal film and a titanium-based metal film, and to minimize damage and residue generation to the substrate and the lower insulating film It is an object to provide an etching solution composition.

The present invention is water-soluble having 0.1 to 5% by weight of inorganic salt oxidizing agent, 0.1 to 5% by weight of chlorine-containing compound, 0.01 to 2% by weight of fluorine-containing compound, 0.1 to 10% by weight of amino group and carboxyl group Provided is an etching liquid composition of a multilayer including a copper-based metal film and a titanium-based metal film including a compound and a residual amount of water.

The etchant composition of the present invention provides an excellent etching profile during the etching of multiple films including a copper-based metal film and a titanium-based metal film, and the subsequent process can be stably performed by minimizing damage and residues on the substrate and the lower insulating film. To be.

In addition, the etching liquid composition of the present invention, as in the case of chromium or the like, it is possible to manufacture a flat panel display in an environmentally friendly manner by making it possible to replace the substances defined as environmentally harmful substances with copper.

The present invention is 0.1 to 5% by weight inorganic salt oxidizing agent, 0.1 to 5% by weight chlorine-containing compound, 0.01 to 2% by weight fluorine-containing compound, 0.1 to 10% by weight of a water-soluble compound having an amino group and a carboxyl group and the remaining amount of water It relates to an etching liquid composition of a multilayer including a copper-based metal film and a titanium-based metal film.

In the present invention, the copper-based metal film means a copper film or a copper alloy film, and the titanium-based metal film means a titanium film or a titanium alloy film. Further, the multilayer film including the copper-based metal film and the titanium-based metal film includes, for example, a "titanium-based metal film / copper film-based metal film" and a titanium-based metal film having a copper-based metal film as a lower film and a titanium-based metal film as an upper film. A double film of "copper metal film / titanium metal film" having a lower film and a copper metal film as an upper film, and further comprising a titanium metal film / copper metal film / titanium metal film or a copper metal film / It also includes the case of multiple films of triplet or more in which copper-based metals and titanium-based metal films are alternately laminated, such as titanium-based metal films / copper-based metal films. Such a multilayer may determine the structure of the multilayer in consideration of a combination of materials constituting the membrane disposed on the upper portion of the membrane or the membrane disposed below, or adhesion to the membranes. In addition, the copper film and the titanium film are not limited in thickness to each other, and various combinations are possible. For example, the thickness of the copper film may be larger than that of the titanium film, or may be small.

The inorganic salt oxidizing agent, chlorine-containing compound, fluorine-containing compound, water-soluble compound having an amino group and a carboxyl group, and an etchant composition including deionized water of the present invention can be prepared by a known method, and have a purity for semiconductor processing. It is desirable.

In the present invention, the inorganic salt oxidizing agent is a main component for etching the copper-based metal film, and is contained in an amount of 0.1 to 5% by weight based on the total weight of the composition. There is no advantage, and if it exceeds 5% by weight, overetching may occur and wiring may be lost.

Examples of the inorganic salt oxidizing agent include CuCl ₂ , Cu (NO ₃ ) ₂ , CuSO ₄ , and the like, and these may be used alone or in combination of two or more.

The chlorine-containing compound in the present invention means a compound capable of dissociating chlorine ions, and serves as an auxiliary oxidant for etching the copper-based metal film. When the chlorine-containing compound is contained in 0.1 to 5% by weight based on the total weight of the composition, when contained in less than 0.1% by weight, the etching rate of the copper-based metal film is lowered, so that the etching profile is poor, and exceeds 5% by weight. Over-etching can occur and wiring can be lost.

Examples of the chlorine-containing compound include HCl, NaCl, KCl, NH ₄ Cl, and the like, which may be used alone or in combination of two or more.

In the present invention, the fluorine-containing compound serves as a main component for etching the titanium-based metal film, it is contained in 0.01 to 2% by weight relative to the total weight of the composition. If the content is less than 0.01% by weight, the etching rate of the titanium-based metal film may be lowered, and residues may occur. If the content exceeds 2% by weight, the substrate (Glass, etc.) and the insulating film (silicon film, etc.) may be damaged. .

The fluorine-containing compound means a compound capable of dissociating fluorine ions or polyatomic fluorine ions. Examples of the fluorine-containing compound include ammonium fluoride, sodium fluoride, potassium fluoride, ammonium bifluoride, sodium bifluoride and potassium bifluoride. These may be used alone or in combination of two or more.

 In the present invention, the water-soluble compound having an amino group and a carboxyl group serves to control the etching rate between copper and other metals in the copper-containing film by inhibiting the etching of copper. The compound is preferably contained in 0.1 to 10% by weight based on the total weight of the composition. When contained in less than 0.1% by weight, the etching rate of copper and titanium is too high, so that the side etching is large, a bad profile is generated, when exceeding 10% by weight, the etching rate of copper and titanium is too suppressed, the residue The probability of occurrence is high.

Examples of the water-soluble compound having an amino group and a carboxyl group include alanine, aminobutyric acid, glutamic acid, glycine, glycine, iminodiacetic acid, nitrilotriacetic acid and sarco And sarcosine, and these may be used alone or in combination of two or more.

Water used in the present invention means deionized water and is used for the semiconductor process, preferably water of 18 dl / cm or more.

The etchant composition of the present invention may further include at least one of an etch regulator, a surfactant, a metal ion sequestrant, a corrosion inhibitor and a pH regulator in addition to the above-mentioned components.

In addition,

It provides a method for producing a thin film transistor comprising the step of forming a pattern of metal wiring using the etchant composition.

According to the above manufacturing method, it is possible to form a metal wiring in an excellent state on the thin film transistor, it is possible to manufacture a thin film transistor of excellent quality.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention more specifically, but the scope of the present invention is not limited by the following examples. The following examples can be appropriately modified and changed by those skilled in the art within the scope of the present invention.

Examples 1 to 8 and Comparative Examples 1 to 3: Preparation of the etchant composition

According to the component and the composition ratio shown in Table 1 was prepared so that the etching solution composition is 180 kg.

CuCl ₂ NaCl NH ₄ FHF C ₂ H ₅ NO ₂ water Example 1 0.3 0.1 0.2 0.5 98.9 Example 2 0.3 0.5 0.2 0.5 98.5 Example 3 0.5 0.2 0.2 1.0 98.1 Example 4 0.5 0.5 0.2 0.7 98.1 Example 5 1.0 0.3 0.2 0.5 98.0 Example 6 1.0 0.5 0.3 1.0 97.2 Example 7 3.0 0.2 0.3 2.0 94.5 Example 8 3.0 1.0 0.3 2.0 93.7 Comparative Example 1 9 2 0.2 0.2 88.6 Comparative Example 2 0.5 0.05 0.01 0.8 98.64 Comparative Example 3 0.3 0.1 0.3 15.0 84.3

Test Example: Evaluation of Etch Characteristics

A copper / titanium double layer was deposited on a silicon layer on a glass substrate, and a substrate on which a photoresist was patterned in a uniform form was used as a specimen.

Example 1 to 8 and Comparative Examples 1 to 8 in the experimental equipment of the spray etching method (manufactured by SEMES, model name: ETCHER (TFT)) After each of the etchant prepared in 3, the temperature was set to 25 ° C and warmed up, the temperature reached 25 ± 0.1 ° C, and then the etching process was performed. Total etch time was given at 30% based on EPD. Insert the specimen, start spraying, and when the etching is complete, taken out, washed with deionized water, dried using a hot air drying apparatus, and removed the photoresist using a photoresist stripper (PR) stripper. After cleaning and drying, an electron scanning microscope (SEM: manufactured by Hitachi, model name: S-4700) was used to evaluate the inclination angle of the etching profile, the loss of side etch (CD), the etching residue and the underlying film damage. The results are shown in Table 2.

[Evaluation Criteria of Etch Profile]

◎: Very good (CD Skew: ≤1㎛, Taper Angle: 30 ° ~ 60 °)

○: Excellent (CD Skew: ≤1.5㎛, Taper Angle: 30 ° ~ 60 °)

△: Good (CD Skew: ≤2㎛, Taper Angle: 30 ° to 60 °)

×: defective (metal film loss and residue)

Type of thin film Etch Profile Glass and silicon film damage Residue Example 1 Cu / Ti ◎ none none Example 2 ◎ none none Example 3 ◎ none none Example 4 ◎ none none Example 5 ◎ none none Example 6 ◎ none none Example 7 ◎ none none Example 8 ◎ none none Comparative Example 1 × Cu Pattern Loss Comparative Example 2 × Ti Unetch Comparative Example 3 × Cu unetch

As confirmed in Table 2, the etchant composition of Examples 1 to 8 had excellent etching profiles, no damage to the glass substrate and the silicon layer, and showed excellent etching characteristics without residue. On the other hand, and Comparative Examples 1 to The etchant composition of 3 was found to be unsuitable for use because of poor etching profiles, unetch of copper and titanium films, and loss of copper patterns.

FIG. 1 is an electron scanning micrograph showing the result of etching a Cu / Ti double layer with the etchant of Example 1. FIG.

FIG. 2 is an electron scanning micrograph showing the result of etching a Cu / Ti double layer with the etchant of Comparative Example 1. FIG.

Claims (6)

0.1 to 5% by weight of inorganic salt oxidizing agent, 0.1 to 5% by weight of chlorine-containing compound, 0.01 to 2% by weight of fluorine-containing compound, 0.1 to 10% by weight of water-soluble compound having amino group and carboxyl group and remaining amount An etching liquid composition of a multilayer comprising a copper-based metal film and a titanium-based metal film containing water. The etchant composition according to claim 1, wherein the inorganic salt oxidizing agent is one or two or more selected from the group consisting of CuCl ₂ , Cu (NO ₃ ) ₂ and CuSO ₄ . The etchant composition according to claim 1, wherein the chlorine-containing compound is one or two or more selected from the group consisting of HCl, NaCl, KCl, and NH ₄ Cl. The etchant composition according to claim 1, wherein the fluorine-containing compound is one or two or more selected from the group consisting of ammonium fluoride, sodium fluoride, potassium fluoride, ammonium bifluoride, sodium bifluoride and potassium bifluoride. The method of claim 1, wherein the water-soluble compound having an amino group and a carboxyl group is alanine (aminoine), aminobutyric acid (aminobutyric acid), glutamic acid (glutamic acid), glycine (glycine), iminodiacetic acid, nitrilotriacetic acid) and sarcosine, an etching solution composition characterized in that one or two or more selected from the group consisting of. A method of manufacturing a thin film transistor comprising the step of forming a pattern of a metal wiring using the etchant composition of claim 1.

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