KR20100040004A - Echant without hydrogen peroxide for layers of copper or copper alloy - Google Patents

Abstract

PURPOSE: An etching agent of non-peroxide hydrogen type copper or a copper alloy film is provided to obtain a wire in which a copper layer is not corroded and to increase the lifetime of copper in comparison with the etching agent of a peroxide hydrogen type. CONSTITUTION: An etching agent of copper or a copper alloy film comprises peroxide 3~30 weight%, one or more organic acid 1~20 weight%, chelating agent 0.01~1 weight%, oxidation stabilizer 0.01~5 weight%, inorganic acid 0.1~5 weight%, surfactant 0.001~0.5 weight%, and water. The peroxide is potassium persulphate, sodium perchlorate, potassium perchlorate, perchloric acid calcium, potassium peroxide, sodium peroxide, calcium peroxide, ammonium persulfate, sodium persulphate, perchloric acid, potassium permanganate, sodium permanganate, potassium dichromate, or sodium bichromate.

Description

Etcher without hydrogen peroxide for layers of copper or copper alloy

The present invention relates to a Cu etchant, more particularly, an etchant of two or more multilayers of copper or copper alloy / other metals, other metal alloys or metal oxides containing other peroxides instead of hydrogen peroxide.

Flat panel displays such as LCDs, PDPs and OLEDs, in particular TFT-LCDs, are large screens, in order to reduce wiring resistance and increase adhesion with a silicon insulating film, or even a single film of copper or copper alloy, or even copper or copper Adoption of two or more multilayers of alloys / other metals, intermetal alloys or metal oxides has been widely studied. For example, a copper / molybdenum film, a copper / titanium film, or a copper / molybdenum-titanium film can form source / drain wirings that form the gate wiring and data lines of the TFT-LCD, thereby contributing to the large screen of the display. Can be. Accordingly, there is a demand for the development of an etchant (or “etchant”) capable of simultaneously removing these multiple films and leaving no etching solution and no metal residue on the substrate after washing.

Korean Patent Laid-Open Publication Nos. 2003-0084397 and 2004-0051502 disclose etching agents for copper / molybdenum films containing hydrogen peroxide, organic acids, phosphates, sulfates, nitrogen ring compounds and other nitrogen compounds. In addition, Korean Patent Publication No. 10-2006-0064481 (Patent Registration No. 708970) discloses 4-40 parts by weight of hydrogen peroxide + 0.1-10 parts by weight of organic acid + 0.1-10 parts by weight of triazole or tetrazole + 0.1-10 parts by weight of amino compound. An etchant using a minor + small amount of fluoride is disclosed. However, the above etchant did not satisfy the high requirements in terms of CD loss, taper, pattern straightness, and metal residue for the copper alloy.

The etchant based on hydrogen peroxide may have difficulty in securing stability and increasing productivity due to instant boiling under severe production conditions.

The present invention is to provide a copper or copper alloy film etching agent having a stable etching, easy control and excellent productivity because the rapid etching rate does not occur with copper.

In particular, the present invention is to provide a copper or copper alloy film etchant having a taper of less than 60 degrees, a CD loss of 1 μm or less, a good linearity of the pattern, and a low resorption rate of the metal residue.

In addition, the present invention is to provide an etchant for simultaneously etching two or more multilayers made of a copper or copper alloy film and another metal film.

According to the present invention, potassium persulfate (K ₂ O ₈ S ₂ ), sodium perchlorate (NaClO ₄ ), potassium perchlorate (KClO ₄ ), calcium perchlorate (Ca (ClO ₄ ) ₂ ), potassium peroxide (K ₂ O ₂ ) , Sodium peroxide (Na ₂ O ₂ ), calcium peroxide (CaO ₂ ), ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ), sodium persulfate (Na ₂ S ₂ O ₈ ), perchloric acid (HClO ₄ ), permanganic acid 3-30 wt% peroxide selected from the group consisting of potassium (KMnO ₄ ), sodium permanganate (NaMnO ₄ ), potassium dichromate (K ₂ Cr ₂ O ₇ ), sodium dichromate (Na ₂ Cr ₂ O ₇ ) and mixtures thereof ; 1 to 20% by weight of one or more organic acids selected from the group consisting of carboxylic acids and sulfonic acids; 0.01 to 1 wt% chelating agent; 0.01-5% by weight of an oxidative stabilizer; 0.1-5% by weight of inorganic acid; 0.001-0.5 wt% surfactant; And a copper or copper alloy film etchant consisting of water residual amount. As needed, 0.001-0.5 weight% of fluorine ion providing agents are further contained. The etchant may simultaneously etch a double film made of a copper or copper alloy film and another metal film or three or more multilayer films in which they are alternately stacked. The other metal is preferably molybdenum, titanium, tungsten or an alloy thereof.

The peroxide is a material used as an oxidant of the etchant of the present invention serves to move the corrosion potential of copper to the anode to enable etching. In other words, it can be said that it forms a soluble passivation capable of Cu ionization with copper in a metal state. The peroxide of the present invention is preferably ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ), sodium persulfate (Na ₂ S ₂ O ₈ ), perchloric acid (HClO ₄ ), potassium permanganate (KMnO ₄ ), sodium permanganate ( NaMnO ₄ ), potassium dichromate (K ₂ Cr ₂ O ₇ ), sodium dichromate (Na ₂ Cr ₂ O ₇ ) and mixtures thereof, preferably used in an amount of 5 to 15% by weight.

The carboxylic acid preferably has 1 to 3 carboxyl groups having 1 to 12 carbon atoms, for example, acetic acid (C ₂ H ₄ O ₂ ), oxalic acid (C ₂ H ₂ O ₄ ), glycolic acid (C ₂ H ₄ O ₃ ), glutamic acid (C ₅ H ₉ NO ₄ ), butanoic acid (C ₄ H ₈ O ₂ ), malonic acid (C ₃ H ₄ O ₄ ), gluconic acid (C ₆ H ₁₂ O ₇ ), formic acid (CH ₂ O ₂ ), propionic acid (C ₃ H ₆ O ₂ ), citric acid (C ₆ H ₈ O ₇ ) or succinic acid (C ₄ H ₆ O ₄ ) and the sulfonic acid is preferably methanesulfonic acid (CH ₃ SO ₃ H ) And ethanesulfonic acid (CH ₃ CH ₂ SO ₃ H). Carboxylic acid or sulfonic acid is preferably used within 2-10w%. The carboxylic acid or sulfonic acid provides an environment in which copper, molybdenum, titanium, tungsten, and the laminated film can be simultaneously etched, and acts as a buffer for metal ions as well as a buffer against acidity change.

The chelating agent is preferably used in an amount of 0.01 to 0.5 w%, for example, nitrilotriacetic acid ("NTA"), ethylenediaminetetraacetic acid ("EDTA"), diethylenetriaminepentaacetic acid ("DTPA" "), Aminotri (methylenephosphonic acid) (" ATMP "), 1-hydroxyethane (1,1-diylbisproponic acid) (" HEDP "), 5-amino tetrazole (" 5-ATZ "), BenzoTriazole (" BTA "), ethylenediaminetetra (methyleneproponic acid) (" EDTMP "), diethylenetriaminepenta (methylenephosphonic acid) (" DTPMP "), methylgal Methyl (3,4,5-Trihydroxy benzoate) and propyl gallate (3,4,5-Trihydroxybenzoic acid propyl ester) are used.

Cu is easily dissolved due to its properties of being easily attached to impurities, but if it is left as a metal that is easily reattached, Cu is likely to remain a major factor that may cause defects in subsequent processes. In order to solve this problem, a chelating agent is added as the metal ion blocking agent.

As glass etching continues, the peroxide-based materials used as oxidants start to decompose little by little, and thus an oxidation stabilizer is required to stabilize them, and glycol derivatives are used. Such glycol derivatives are represented by R ₁ (OR ₂ ) OH where R ₁ = C _n H _{2n + 1} (n = 1-4) and R ₂ = C _m H _2m (m = 2-3). Preferably, HP-3 (trade name) which is one of 3M's HP-family is used. Depending on the addition of oxidizing stabilizer, the life time of the solution is 20 ~ 30% difference. Preferably 0.05 to 1% by weight is used.

Inorganic acid is used to assist the etching rate and to sharpen the taper, and the types thereof include phosphoric acid (H ₃ PO ₄ ), nitric acid (HNO ₃ ), sulfuric acid (H ₂ SO ₄ ), hydrochloric acid (HCl), and carbonic acid ( H ₂ CO ₃ ), perchloric acid (HClO ₄ ), and the like.

In the present invention, the surfactant adsorbs on the glass surface to quickly release the generated metal ions and does not reattach the dropped metal ions. The surfactant is preferably a fluorine-based surfactant. Fluorine-based surfactants also significantly improve cleaning efficiency. Fluorine-based surfactants include, for example, R _f CH ₂ CH ₂ SCH ₂ CH ₂ CO ₂ Li, (R _f CH ₂ CH ₂ O) P (O) (ONH ₄ ) ₂ , (R _f CH ₂ CH ₂ O) ₂ P (O) (ONH ₄ ), R _f CH ₂ CH ₂ O (CH ₂ CH ₂ O) _y H, R _f CH ₂ CH ₂ SO ₃ X, R _f CH ₂ CH ₂ NHSO ₃ X or mixtures thereof (Wherein y is an integer of 8 to 15, X is H or NH ₄ , R _f is F (CF ₂ CF ₂ ) _z , and z is an integer of 3 to 8). The surfactant is preferably used in an amount of 0.001 to 0.5w%, and when excessively added, a large amount of bubbles are generated and the efficiency is reduced and damage to the glass plate may occur.

As the fluorine ion providing agent, hydrofluoric acid, ammonium fluoride, ammonium bifluoride, sodium fluoride, potassium fluoride, and the like may be used. Hydrochloric acid can be used. The concentration of fluorine ions is preferably 0.001 to 0.5% by weight. When the molybdenum film is etched, a small particle form residue is generated due to the molybdenum film property, which later becomes an important defect factor that causes electrical short or decreases luminance. The fluorine ion donor serves to remove the residue and plays an essential role in the etching of Ti. The Ti film having a thickness of 100 GPa is etched within 30 sec at room temperature (25 ° C). In view of this, the fluorine-based surfactant is a major factor for removing the molybdenum (Mo) residue on the substrate and etching of Ti.

The etchant of the present invention is applied to two or more multilayers of copper or copper alloy / other metals, other metal alloys or metal oxides. In the case of a two-layer film, it is specifically applied to Cu / Mo, Cu / Mo-Ti, Cu / Mo-W, Cu / Ti. In the case of a three-layer film, specifically, it can be applied to the film | membrane of copper / molybdenum / titanium which makes copper upper and molybdenum / titanium lower.

Referring to the case where the etchant of the present invention is applied to a Cu / Mo-Ti double layer, as illustrated in FIG. 1, Mo-Ti and Cu deposition are performed on a glass substrate, followed by coating a photoresist as shown in FIG. 2. After the pattern is formed by photolithography as shown in FIG. 3 and the etching process as shown in FIG. 4 is removed, the photoresist is removed as shown in FIG.

By etching the copper and copper alloy films using the etchant according to the present invention, it is possible to obtain wirings in which the adhesion to the bottom of the multilayer film is maintained, has a good profile, and the copper layer is not corroded. In addition, as compared to the hydrogen peroxide type etching agent, the safety and life time is excellent, thereby increasing productivity and improving the process.

Hereinafter, the present invention will be described in detail with reference to the following examples.

Examples 1-10

The substrate used in the present invention is a glass plate coated with molybdenum-titanium over 100 kPa on non-alkali glass and 2500 kPa coated with a copper film thereon. The photoresist process to confirm the performance of the etchant is shown in the following table. PR is an abbreviation for photoresist and novolak is a photoresist in which the exposed part is melted during the development process. EOP is an abbreviation of End Of Point. It is the point of time when a pattern is formed as it is exposed to the edge during exposure. S / B is an abbreviation of Soft baked. It is a baking process to volatilize the solvent after coating the photoresist, and H / B is a hard bake. As a medical term, it is a baking process for preservation and curing of patterns after development.

PR RPM EOP S / B H / B Develop Novolak 1500 rpm / 10 sec 5.6 mJ / sec 110 / 120sec 110 / 120sec TMAH2.38w% / 60sec

For the variety and practicality of the test, the test substrate was cut to 100 * 100mm size and tested. The above-described PR coating process and etching process are shown in FIGS. 1 to 5. The equipment used in this example is a large etchant designed for copper etching, which can handle up to 5G glass substrates and can store up to 200 liters of solution in acid-resistant (Teflon) material suitable for use in strong acids. The tank is at the bottom and uses a magnetic pump (100 liters / min) designed for self-suction. In addition, the spray was evenly distributed through a horizontal spray nozzle composed of a full con type.

The device consists of a glass substrate inlet, etching zone, rinse zone, and drying zone. By using transparent PVC, the etching process can be visually checked, and the problem that may occur during the process and the etching process can be visually monitored. . The rinse zone adopts a drain method to minimize glass contamination by cleaning, and the control unit can automatically and manually adjust using a touch panel. It is designed to control heating and cooling automatically to prevent temperature rise.

The etching solution for testing the specimen is a composition ratio as shown in Table 1 and the rest is deionized water. The combination order was combined in the same order as above. Since copper itself is strongly attached to impurities, the test was performed by filtering with a 0.1 ㎛ filter. The test capacity is 50 liters average and may be less or more than this.

Next, the photograph (FIGS. 6 to 9) taken as a criterion for evaluation of physical properties is the result of the precise photographing by FE-SEM. The specimen used at this time is a glass substrate that has undergone a gate process in the manufacture of a TFT circuit of a liquid crystal display device. Mo-Ti 100 Å and Cu 2500 Å were formed thereon, PR was applied, dried, exposed and developed to complete the pattern formation. Profiles are evaluated with reference to the following criteria. The measurement of the CD loss and taper was measured by 3,000 ~ 40,000 magnification of the specimen without peeling the PR. The straightness of the pattern and the residue were measured in the same manner as above after removing the PR with KOH 4wt% solution.

Physical property test results are shown in Table 1.

Table 1.

division Composition (parts by weight) sodium persulfate / MSA / BTA / HP-3 / nitric acid / ammonium bifluoride / TFT Properties CD loss Taper Pattern straightness Residue Example One 10/5 / 0.7 / 0.05 / 0.3 / 0.4 / 0.01 ◎ O O O 2 13/3 / 0.5 / 0.03 / 0.2 / 0.1 / 0.005 O ◎ △ O 3 15/10 / 0.2 / 0.01 / 0.1 / 0.2 / 0.03 △ △ O ◎ 4 17/5 / 0.4 / 0.04 / 0.3 / 0.3 / 0.1 O O ◎ △ 5 5/15 / 0.8 / 0.05 / 0.5 / 0.3 / 0.07 △ △ ◎ O 6 7/5 / 0.2 / 0.03 / 0.7 / 0.1 / 0.05 ◎ △ O ◎ 7 3/20 / 0.1 / 0.09 / 0.5 / 0.3 / 0.002 O O △ ◎ 8 10/5 / 0.3 / 0.04 / 0.4 / 0.6 / 0.03 △ ◎ △ △ 9 15/7 / 0.5 / 0.07 / 0.3 / 0.4 / 0.01 ◎ ◎ △ ◎ 10 10/10 / 0.7 / 0.06 / 0.6 / 0.2 / 0.02 △ △ O ◎

BTA: Benzotriazole

HP-3: HP-series (trade name of 3M company)

MSA: Methane sulfonic acid

TFT: 3M fluorine-based surfactant

CD Ross: ◎; O within 500 nm; Within 1 μm Δ; Within 1-1.5 μm x; 1.5 ㎛ or more

Slope: ◎; 40-50 degrees O; 50 to 60 degrees Δ; 60-70 degrees x; More than 70 degrees

Pattern straightness & residue: ◎; Very good O; Good Δ; Usually x; Bad

FIG. 1 shows a specimen used in the present invention in which Mo-Ti deposition and Cu deposition are performed on a glass substrate.

Figure 2 is a form coated with PR on the specimen.

Figure 3: The photolithography process is completed on the specimen.

4 is a form after an etching process with an etchant according to the present invention.

Fig. 5: Form after peeling off the photoresist after etching according to the present invention.

6 is a photograph showing the straightness of the pattern according to the present invention.

7 is an enlarged photograph showing confirmation of straightness and no residue on the substrate.

8 is a photograph showing a profile without peeling off the photoresist after pattern formation. It shows the superiority of cd loss and taper.

9 is a photograph showing that Mo-Ti residues remain upon etching with an etchant according to the prior art.

Explanation of the Main References

10; Glass substrate 11; Mo-Ti deposited film 12; Cu deposited film 13; Photoresist

Claims (5)

Potassium persulfate (K ₂ O ₈ S ₂ ), sodium perchlorate (NaClO ₄ ), potassium perchlorate (KClO ₄ ), calcium perchlorate (Ca (ClO ₄ ) ₂ ), potassium peroxide (K ₂ O ₂ ), sodium peroxide (Na ₂ O ₂ ), calcium peroxide (CaO ₂ ), ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ), sodium persulfate (Na ₂ S ₂ O ₈ ), perchloric acid (HClO ₄ ), potassium permanganate (KMnO ₄ ) 3 to 30 wt% peroxide selected from the group consisting of sodium permanganate (NaMnO ₄ ), potassium dichromate (K ₂ Cr ₂ O ₇ ), sodium dichromate (Na ₂ Cr ₂ O ₇ ), and mixtures thereof; 1 to 20% by weight of one or more organic acids selected from the group consisting of carboxylic acids or sulfonic acids; 0.01 to 1 wt% chelating agent; 0.01-5% by weight of an oxidative stabilizer; 0.1-5% by weight of inorganic acid; 0.001-0.5 wt% surfactant; And a copper or copper alloy film etchant comprising a residual amount of water. The copper or copper alloy film etchant of claim 1, wherein the fluorine-based surfactant is 0.001 to 0.5% by weight and the etchant further comprises 0.001 to 0.5% by weight of a fluorine ion donor. The etchant according to claim 1, wherein the etchant is capable of simultaneously etching a double film made of a copper or copper alloy film and another metal film, or three or more multilayer films in which they are alternately stacked. The etchant according to claim 2, wherein the other metal is preferably titanium, molybdenum, tungsten or an alloy thereof. The method of claim 1, wherein the carboxylic acid is acetic acid (C ₂ H ₄ O ₂ ), oxalic acid (C ₂ H ₂ O ₄ ), glycolic acid (C ₂ H ₄ O ₃ ), glutamic acid (C ₅ H ₉ NO ₄ ), Butanoic acid (C ₄ H ₈ O ₂ ), malonic acid (C ₃ H ₄ O ₄ ), gluconic acid (C ₆ H ₁₂ O ₇ ), formic acid (CH ₂ O ₂ ), propionic acid (C ₃ H ₆ O ₂ ) , Citric acid (C ₆ H ₈ O ₇ ) or succinic acid (C ₄ H ₆ O ₄ ) and the sulfonic acid is methanesulfonic acid (CH ₃ SO ₃ H) or ethanesulfonic acid (CH ₃ CH ₂ SO ₃ H) and the chelate Nitrilotriacetic acid ("NTA"), ethylenediaminetetraacetic acid ("EDTA"), diethylenetriaminepentaacetic acid ("DTPA"), aminotri (methylenephosphonic acid) ("ATMP"), 1-hydroxy Ethane (1,1-diylbisproponic acid) ("HEDP"), 5-amino tetrazole ("5-ATZ"), BenzoTriazole ("BTA"), ethylenediamine Tetra (methyleneproponic acid) ("EDTMP"), diethylenetriaminepenta (methylenephosphonic acid) ("DTPMP"), methylgallate (Methyl 3,4,5- Trihydroxy benzoate) or Is propylgallate (3,4,5-Trihydroxybenzoic acid propyl ester) and the fluorine-based surfactant is R _f CH ₂ CH ₂ SCH ₂ CH ₂ CO ₂ Li, (R _f CH ₂ CH ₂ O) P (O) ( ONH ₄ ) ₂ , (R _f CH ₂ CH ₂ O) ₂ P (O) (ONH ₄ ), R _f CH ₂ CH ₂ O (CH ₂ CH ₂ O) _y H, R _f CH ₂ CH ₂ SO ₃ X Or R _f CH ₂ CH ₂ NHSO ₃ X (wherein y is an integer from 8 to 15, X is H or NH ₄ , R _f is F (CF ₂ CF ₂ ) _z , again z is from 3 to 8 And the inorganic acid is phosphoric acid (H ₃ PO ₄ ), nitric acid (HNO ₃ ), sulfuric acid (H ₂ SO ₄ ), hydrochloric acid (HCl), carbonic acid (H ₂ CO ₃ ) or perchloric acid (HClO ₄ ) My.

Images