KR20130061107A - Etching liquid composition for simultaneous etching of a laminate film comprising ti and ti alloy - Google Patents

Abstract

PURPOSE: A metal lamination film etching liquid composition including Ti and a Ti alloy layer is provided to enable coexistence of maintenance of sufficient Ti melting speed and suppression of glass erosivity and to etch a Cu/Ti lamination film without erosion of glass. CONSTITUTION: A metal lamination film etching liquid composition including Ti and a Ti alloy layer comprises acid including fluorine, fluorine compounds generating the acid, and ion. The metal lamination film etching liquid composition etches the metal lamination layer comprised of other metal layer of one layer and a Ti or Ti alloy layer. The metal lamination film is Cu/Ti or Cu/Ti alloy.

Description

Etching liquid composition for simultaneous etching of a laminate film comprising Ti and Ti alloy}

The present invention has a multilayer film having a Ti or Ti alloy layer used for a display device of a FPD (flat panel display), a solar cell, an electrode of a touch panel, or the like, for example, having a Ti or Ti alloy layer present on a SiO ₂ or Si substrate. The batch etching liquid composition of a multilayer film is related.

Al has been used for electrodes and wiring materials of liquid crystal displays, but as the size of the substrate increases, signal transmission delay becomes a problem because the gate lines and data lines connected to the thin film transistors become longer. Therefore, the development and practical use of lower resistance Cu wiring has become active in recent years, and the application to 3D liquid crystal television is also expected.

When Cu is used as an electrode and wiring, Cu is not used as a single layer, but a metal such as Ti, Mo, MoTi is used as an adhesion layer or a barrier layer for the purpose of improving adhesion to a glass substrate or blocking diffusion of Cu. Should be used. In that case, there have been attempts to use the electrode in the form of a laminated film of Cu / Ti, Ti / Cu / Ti, Mo / Cu / Mo, Cu / Mo, MoTi / Cu / MoTi, Cu / MoTi.

The metal laminated film having a Ti or Ti alloy layer is used for FPDs such as ELD (electroluminescent display), solar cells, touch panels and the like, without being limited to the metal laminated film using Cu as the electrode wiring. Various methods for efficiently microfabricating such a metal laminated film have been studied.

In the conventional etching method of the Cu / Ti laminated film, the Cu wet layer is difficult to dry-etch, so the bulk wet etching of Cu / Ti is mainstream. As the Cu / Ti batch etching solution, it has already been practically used as an oxidizing agent for dissolving Cu, including peroxides such as hydrogen peroxide and peroxosulfate (persulfuric acid), and fluoride for dissolving Ti (Patent Document 1).

There is also a method of etching Cu and Ti separately (Cu is wet, Ti is wet or dry), but batch etching is preferable because the process is complicated by two steps.

However, in the above Cu / Ti batch etching solution, it is known that the Cu ions dissolved in the liquid accelerate the decomposition of hydrogen peroxide and persulfate to generate oxygen. For this reason, there is a problem in that a large amount of oxidizing agent is consumed at the time of use, consuming more than the consumption amount corresponding to the number of sheets processed by the panel. In addition, there is a problem that the explosion risk is accompanied because the pressure in the container containing the etching solution increases due to the generation of oxygen. For these reasons, a Cu / Ti batch etching solution using an oxidant in place of hydrogen peroxide and persulfate is desired.

As oxidants other than peroxides, stable HNO ₃ is effective even in the presence of Cu ions. The etching solution using HNO ₃ as an oxidizing agent is known as a mixed acid system (H ₃ PO ₄ + HNO ₃ + AcOH, H ₂ SO ₄ + HNO ₃ + AcOH), and is mainly used as an etching solution of Al. Even in the etching of Cu, it is possible to control the dissolution rate of Cu in an optimal range by adjusting the concentration of HNO ₃ and other acids. By adding fluoride to this, collective etching of Cu / Ti becomes possible.

Some etching liquids use inorganic oxidizing agents (polyvalent ions such as Fe, Cu, and Al), but there are problems such as difficulty in controlling Cu dissolution rate, large SE (side etching), and uneven shape of pattern edges. . Larger S. E. is a problem because the line width of the metal wiring becomes smaller, leading to an increase in electrical resistance. If the pattern edge shape is bad, there is a problem of disconnection or short, resulting in poor step coverage in the thin film formation step of the next step. Therefore, it is thought that finding a favorable Cu / Ti collective etching liquid based on this composition is more difficult than a mixed acid system.

For this reason, it is thought that Cu / Ti package etching liquid using oxidizing agents other than a peroxide is a mixed acid base which combined fluoride and a mixed acid type. However, if Cu / Ti is collectively etched with a mixed acid base, there is no problem in terms of SE and pattern edge shapes, but the Cu layer does not dissolve in the base glass due to erosion, low in-plane uniformity, long treatment time, and initial liquid. There was a problem.

In particular, the high glass erosion property of the etching solution causes a decrease in the yield, so improving this is a problem to be prioritized. In order to suppress free erosion, it is effective to lower the fluoride concentration, but since Ti is also dissolved by the fluoride, the dissolution rate of Ti also decreases. For this reason, it was difficult to attain both sufficient maintenance of Ti dissolution rate and suppression of free erosion.

The following briefly introduces the main prior art different from the present invention.

Unexamined-Japanese-Patent No. 2005-097715 (patent document 2) is characterized by including hydrofluoric acid as a main component as a Ti containing layer etching liquid, and the composition which further contains an oxidizing agent (nitric acid or hydrogen peroxide solution) is disclosed. In addition, Patent Document 2 discloses a method of etching a Ti-containing layer in which a pattern made of a metal (Pt, Au, Ag, Cu, Pd) other than Ti is formed on the Ti-containing layer. However, in the case of Patent Document 2, the metal such as Cu on the Ti-containing layer is etched by another etching solution, and the Ti-containing layer is only described as being capable of etching by the etching solution using the upper metal as a mask pattern. That is, the etching liquid disclosed in patent document 2 is a liquid which selectively etches Ti without etching metals other than Cu, and its use differs from this invention.

Unexamined-Japanese-Patent No. 2010-114415 (patent document 3) is the etching liquid of the single film | membrane comprised by Cu or Cu alloy, and the laminated | multilayer film or more. If the etching because the etchant is disclosed in Patent Document 3, as an oxidizing agent for Cu dissolved does not include but contains HNO _3, fluorides, Cu / Ti layered film, Ti layer is thought that could be etched.

US Patent No. 5298117 (Patent Document 4) discloses a process of etching Cu / Ti with fluorine + copper chloride + chloride. Patent Document 4 describes the shape of the undercut and the etching cross section, but does not mention the specific etching rate.

Korean Patent Publication No. 10-0419071 (Patent Document 5) does not contain hydrogen peroxide as a composition, and as an oxidizing agent, inorganic salts (CuCl ₂ , Al (NO ₃ ) ₃ , FeCl ₃ ), inorganic acids, fluorine sources, And pyridine and the like. In Patent Document 5, an inorganic salt (metal salt) is used as an oxidizing agent for etching, whereas in the etching solution of the present invention, an inorganic salt (metal salt) is added to coordinate free fluorine ions to suppress free erosion. Document 5 and the present invention have a different purpose. Further, in Patent Document 5, pyridine and other nitrogen-containing organic solvents are added in order to control the taper shape and to suppress attack on glass, but there is a problem in the waste liquid treatment.

Korean Patent Publication No. 10-0596468 (Patent Document 6) proposes a mixture of HF and HNO ₃ + CH ₃ COOH as an etching liquid composition. However, in the case of Patent Document 6, the etching target is different from Ti / Cu / glass, and in the above-mentioned Patent Document 5, "The taper profile is poor, which causes an attack on the glass substrate and the silicon layer. It is not suitable for. " .

Thus, it is a reality that the etching liquid which is satisfactory enough at the time of batch etching of the metal laminated film which is a Cu / Ti or Cu / Ti alloy layer is not yet developed.

Patent Document 1: US Patent No. 7008548 Patent Document 2: Japanese Unexamined Patent Publication No. 2005-097715 Patent Document 3: Japanese Unexamined Patent Publication No. 2010-114415 Patent Document 4: US Patent No. 5298117 Patent Document 5: Korean Patent Publication No. 10-0419071 Patent Document 6: Korea Patent Publication No. 10-0596468

Accordingly, an object of the present invention is to provide a batch etching solution of a metal laminate film having a Ti or Ti alloy layer, which solves the conventional problems such as glass erosion, in-plane nonuniformity, residue, long processing time, and poor initial solubility of Cu layer. It is in doing it.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, the inventors carried out earnest research, and in order to solve the said subject, the etching solution containing the acid containing fluorine or the fluorine compound which generate | occur | produces the acid, and the ion which can coordinate fluorine is very useful. As a result of further finding and further study, the present invention has been completed.

That is, this invention relates to the following etching liquid, the manufacturing method of this etching liquid, and the etching method using this etching liquid.

[1] An etching liquid for collectively etching a metal laminated film composed of at least one Ti or Ti alloy layer and at least one other metal layer,

An acid containing fluorine or a fluorine compound generating the acid,

The etching liquid containing fluorine-containing ion.

[2] The etching solution according to [1], wherein at least one other metal layer is a metal laminated film made of a Cu layer or a Cu alloy layer.

[3] The etching solution according to [2], wherein the metal laminate film is Cu / Ti or a Cu / Ti alloy.

[4] The acid containing fluorine or the fluorine compound generating the acid is one or two or more selected from the group consisting of HF, NH ₄ F, HBF ₄ , H ₂ SiF ₆ , NaF and KF [1] The etching liquid in any one of [3].

[5] The product of any of [1] to [4], wherein the fluorine-coordinated ion is an ion containing an element selected from the group consisting of Al, Ti, B, Si, Zr, Fe, Mn, Sn, and Mo. Etching liquid of description.

[6] The etching liquid according to any one of [1] to [5], further comprising an oxidizing agent for etching Cu or a Cu alloy.

[7] The etching solution according to [6], wherein the oxidizing agent is nitric acid.

[8] Any one of [1] to [7], further comprising one or two or more acids selected from the group consisting of H ₃ PO ₄ , H ₂ SO ₄ , AcOH, HClO ₄ , HCl and MeSO ₃ H. The etching liquid of one term | claim.

[9] The etching solution according to any one of claims [1] to [8], further comprising one or two or more compounds selected from the group consisting of a compound containing silicide fluoride ions and a water-soluble silicon compound containing silicon. .

[10] The method for producing the etching solution according to any one of [1] to [9], by mixing an acid containing fluorine or a fluorine compound that generates the acid with a fluorine coordinated ion.

[11] A method for collectively etching a metal laminate film made of Ti or a Ti alloy layer and another metal layer by the etching solution according to any one of [1] to [9].

According to the present invention, there is provided a batch etching solution of a metal laminate film having a Ti and Ti alloy layer capable of maintaining a sufficient Ti dissolution rate and suppressing glass erosion.

By the etching solution of the present invention, it is possible to collectively etch the Cu / Ti laminated film formed on the glass substrate without eroding the glass. In addition, the S.E. and pattern edge shapes are also good, and other conventional problems (in-plane uniformity, residue, long processing time, solubility of Cu layer) can also be improved.

Specifically, metals such as Al, Ti, B, Si, Zr, Fe, Mn, Sn, and Mo (preferably Al, Zr, Fe, B) are newly added to the etching solution composition to form metal ions and fluoride ions (F). By controlling the concentration of fluorine in the liquid by coordinating it is possible to suppress free erosion. And by controlling the physical properties by optimizing the composition, it is possible to improve the in-plane uniformity, shorten the treatment time, and improve the solubility of the Cu layer in the initial liquid.

However, although the mechanism of action of the etching according to the present invention is not clear, the fluoride ion concentration in the etching solution etches Ti or the Ti alloy by fluoride ions of an acid containing fluorine coordinated with ions capable of coordinating fluorine. It is considered to be a concentration suitable for the following, and to a concentration which does not erode glass or silicon, and Ti or Ti alloy is selectively etched. The metal of the layer forming the laminated film such as copper is also oxidized by an acid containing fluorine or an oxidizing agent in the etching solution, and it is considered that the batch etching of the metal laminated film having the Ti and Ti alloy layers proceeds further.

1 is a cross-sectional observation diagram of a Cu / Ti substrate subjected to etching treatment for 18 seconds by the liquid of Example 3. FIG.
FIG. 2 is a cross-sectional view of a Cu / Ti substrate etched for 47 seconds with the liquid of Example 4. FIG.
3 is a cross-sectional view of a Cu / Ti substrate etched for 72 seconds with the liquid of Example 5. FIG.
4 is a cross-sectional view of a Cu / Ti substrate etched for 90 seconds with the liquid of Example 6. FIG.
5 is a cross-sectional view of a Cu / Ti substrate etched for 36 seconds with the liquid of Comparative Example 3. FIG.
6 is a cross-sectional observation diagram of a Cu / Ti substrate etched for 47 seconds with the liquid of Comparative Example 4. FIG.
7 is a cross-sectional observation diagram of a Cu / Ti substrate etched for 38 seconds with the liquid of Comparative Example 5. FIG.
8 is a cross-sectional view of a Cu / Ti substrate etched for 27 seconds with the liquid of Comparative Example 6. FIG.

The laminated film etched by the etching solution of the present invention is a laminated film having a Ti or Ti alloy layer formed on a glass or silicon substrate. For example, a film is formed on a glass substrate by sputtering using a Ti or Ti alloy layer as a barrier metal. As a laminated film which formed Cu or other metals on it, the composition of a laminated film is Cu / Ti, Cu / TiMo, Cu / TiFe, Cu / TiZr, etc. are mentioned.

The Ti alloy of the present invention is an alloy containing Ti as a main component and containing Ti and any other metal, for example, 80 wt% or more of Ti, preferably 90 wt% or more of Ti, and more preferably 95 wt% or more of Ti.

In addition, in this invention, Cu / Ti is a 2-layer film, and has shown that it is laminated | stacked in order of Cu and Ti from the surface layer. Moreover, Cu / Ti alloy is a two-layer film, and has shown that it is laminated | stacked in order of Cu and Ti alloy from the surface layer.

The etching solution of the present invention is preferably based on a mixed acid, but the oxidizing agent for metal dissolution is not limited to HNO ₃ , and is not particularly limited as long as it can dissolve Cu. Therefore, it was confirmed that the composition using oxidizing agents other than peroxide can be used as Cu / Ti batch etching liquid.

Oxidant as to etch the Cu contained in the etching solution of the present invention, _{HNO 3, H 2 O 2,} Na 2 S 2 O 8, (NH 4) 2 S 2 O 8, K 2 S 2 O 8, buffer oxo days Potassium sulfate, oxone, LD-100 (manufactured by Dupont), metal salts (CuCl ₂ , FeCl ₃ , Cu (NO ₃ ) ₂ ), and the like. Peroxides such as H ₂ O ₂ , Na ₂ S ₂ O ₈ , (NH ₄ ) ₂ S ₂ O ₈ , K ₂ S ₂ O ₈ , and potassium peroxoyl sulfate have a problem of decomposing in the presence of metal ions. In addition, oxone and LD-100 are the same peroxides as H ₂ O ₂ , Na ₂ S ₂ O ₈ HNO ₃ is preferred as the oxidizing agent because it is more stable than alkaline and the like but easily decomposes under alkaline conditions.

If the HNO ₃ concentration is too low, there is a problem that the number of panels that can be treated is reduced due to low Cu solubility. In addition, when the HNO ₃ concentration is too high, it is difficult to control the etching behavior, the in-plane uniformity is lowered, there is a problem that Cu residue occurs. For this reason, the HNO ₃ concentration is preferably 0.174 to 4.75 mol / l.

Further, the acid is, for example those containing ethyl 3.00~7.39mol / l, the concentration of HNO ₃ 2.75~4.75mol / l is preferred, and acetic acid 3.00~7.39mol / l to adjust the etching rate of Cu Furthermore, when it contains 3.00-4.00 mol / l of perchloric acid, sulfuric acid, phosphoric acid, etc., it is preferable that it is 0.174-1.00 mol / l, and it is more preferable that it is 0.3-0.5 mol / l.

Examples of the acid containing fluorine contained in the etching solution of the present invention include HF, NH ₄ F, HBF ₄ , and H ₂ SiF _6. However, when silicate ions are included, H is more effective in suppressing free erosion. ₂ SiF ₆ is preferred. In addition, since H ₂ SiF ₆ has an effect of increasing the Cu dissolution rate, H ₃ PO ₄ , H ₂ SO ₄ , AcOH (acetic acid), HClO ₄ It is also preferable at the point which is effective to improve the problem which a Cu layer does not melt | dissolve with an initial liquid like other acids, such as these.

Regarding the concentration of the acid containing fluorine, for example, the concentration of H ₂ SiF ₆ , if the concentration is too low, there is a problem that the Ti solubility is lowered. If the concentration is too high, as described below, a large amount of metal ions may be required corresponding to the H ₂ SiF ₆ concentration, so that the solubility of the metal ions may exceed the upper limit. For these reasons, the concentration of H ₂ SiF ₆ is preferably 0.12 to 0.35 mol / l, more preferably 0.12 to 0.175 mol / l.

Examples of the metal ions contained in the etching solution of the present invention include Al, Ti, B, Si, Zr, Fe, Mn, Sn, Mo, and the like. However, Al, Zr from the viewpoint of being easy to coordinate with fluoride and effective in suppressing glass erosion. , Fe, B are preferred, and Al, Zr, and B are preferred from the viewpoint that it is possible to obtain a good taper profile. And Al is preferable from the viewpoint of solubility in aqueous solution. As the metal salt of Al, Al (NO ₃ ) ₃ is preferable because a metal salt containing an anion originally included in the composition is fine. A good taper profile here is etching without etching nonuniformity, and shows the point where the line width etching precision of the etched metal is high, the point where the pattern edge shape is sharp, the point where the pattern shape is taper, etc. If the pattern edge shape is not sharp and becomes an uneven shape, disconnection or short problems will occur, and if the pattern shape cannot obtain a tapered shape, the step coverage will be deteriorated in the thin film formation in the next step.

If the metal ion concentration is too high, Ti can not be dissolved because fluorine ions in the liquid are consumed due to the formation of a complex with the metal ion. On the contrary, if it is too low, the fluorine ions in the liquid are consumed in a large amount and are present in a large amount, thereby greatly eroding the glass. Because of this, metal ion concentrations of acid containing fluorine, such as the amount present for the H ₂ SiF _6. In view of the optimum H ₂ SiF ₆ concentration and solubility of metal ions, 0.058 to 0.116 mol / l is preferable.

In addition to the acid containing fluorine, the etching liquid of this invention may contain the acid for controlling Cu etching behavior further. When an acid for controlling Cu etching behavior is contained, it is possible to further control Cu etching behavior such as Cu etching rate and in-plane uniformity by adjusting the moisture content, viscosity, pH, and the like. Acids for controlling such Cu etching behavior include H ₃ PO ₄ , H ₂ SO ₄ , AcOH, HClO ₄ , HCl, MeSO ₃ H (methanesulfonic acid), and AcOH from the viewpoint of not inhibiting Ti etching. , HClO ₄ , HCl are preferred. Moreover, AcOH and HClO ₄ are more preferable from the viewpoint of improving the etching rate of Cu and the in-plane uniformity during Cu etching.

The metal laminated film is formed on a substrate or a thin film made of a semiconductor or an insulator, but the substrate contains Si as an element impregnated with resin such as glass or silicon, a SiO ₂ substrate or a Si substrate, or a thin film made of SiO ₂ or Si, glass epoxy, or the like. The substrate of the present invention can obtain the effect of the present invention, which does not erode the layer containing Si while etching Ti.

Examples of the acid containing fluorine in the etching solution of the present invention include HF, NH ₄ F, HBF ₄ and H ₂ SiF ₆ , and may be an acid such as HF by adding NaF, KF, or the like.

Example

<Examples 1 and 2, Comparative Examples 1 and 2>

The Example which suppresses the erosion of glass by fluorine ion is demonstrated. HNO ₃ and H ₂ O ₂ as oxidants for dissolving HF and Cu for Ti dissolution, and HClO ₄ , AcOH as other acids when HNO ₃ is an oxidant, and complexes with fluorine ion in the solution the ER (etching rate) of the glass in solution by the addition of AlCl ₃ as a metal ion for measured. The glass used for the test is borosilicate glass (manufactured by Matsunami Glass). The test method computed ER from the weight difference before and after immersion of the glass immersed for 10 minutes on 40 degreeC of liquid temperature, and the stirring speed of 700 r.pm. The results are shown in Table 1.

[Table 1]

From the result of Table 1, it can be confirmed that the erosion of glass is suppressed by addition of not only the kind of Cu oxidant but the ion which can form a complex with fluorine ion.

<Examples 3 to 6>

An embodiment of an etching process according to the present invention will be described. After depositing 350 패턴 of Ti and 350Å of Cu on the glass substrate, a resist pattern was formed and 1.5 times of the time of just etching time under the conditions of 40 ° C. and a stirring speed of 700 r.pm in the etching solution of Table 2. Immersed in. Then, the board | substrate after water washing and drying was observed with the microscope, and the S.E. (side etching amount), taper shape, and residue after etching were evaluated. Treatment time, S. E. is shown in Table 2. Moreover, glass E. R. measured by the method similar to Examples 1-2 is shown in Table 2.

[Table 2]

The photograph which shows the etching result of Examples 3-6 is shown to FIGS. 1-4 (Example 3: 1, Example 4: FIG. 2, Example 5: FIG. 3, Example 6: FIG. 4). In any picture, the tapered shape is relatively good and the etching pattern with less glass erosion can be seen.

<Comparative Examples 3 to 6>

After forming Ti with a film thickness of 350Å and Cu with a film thickness of 4000Å on the glass substrate, a resist pattern was formed, and 1.5 to 4.7 times the just etching time under the conditions of a liquid temperature of 40 ° C. and a stirring speed of 700 r.pm in the etching solution of Table 3. Immersed in time. Then, the board | substrate after water washing and drying was observed with the microscope, and the S.E. (side etching amount), taper shape, and residue after etching were evaluated. Treatment time, S. E. is shown in Table 3. Moreover, the result of having measured glass E. R. similarly to Examples 1-2 is also shown in Table 3.

[Table 3]

The etching result of Comparative Examples 3-6 is shown to FIGS. 5-8 (Comparative Example 3: FIG. 5, Comparative Example 4: FIG. 6, Comparative Example 5: FIG. 7, Comparative Example 6: FIG. 8). It can be seen that the base glass is significantly eroded when the composition is not added with metal ions. Comparative Examples 3 to 6 are compositions excluding only metal ions in Examples 3 to 6, and it can be seen that the glass erosion is greatly increased by removing metal ions.

The etching solution of the present invention can be used as an etching solution for a metal laminate film when forming a wiring or an electrode in a manufacturing process of an electronic device such as a liquid crystal display and a semiconductor device.

Claims (11)

As an etching liquid for collectively etching the metal laminated film which consists of at least 1 layer of Ti or a Ti alloy layer, and at least 1 layer of another metal layer,
An acid containing fluorine or a fluorine compound generating the acid,
An etchant characterized in that fluorine contains a coordinated ion. The method of claim 1,
An etching liquid, wherein at least one other metal layer is a metal laminate film made of a Cu layer or a Cu alloy layer. The method of claim 2,
An etching liquid, wherein the metal laminate film is Cu / Ti or Cu / Ti alloy. 4. The method according to any one of claims 1 to 3,
Etching liquid, characterized in that the acid containing fluorine or the fluorine compound generating the acid is one or two or more selected from the group consisting of HF, NH ₄ F, HBF ₄ , H ₂ SiF ₆ , NaF, and KF. 4. The method according to any one of claims 1 to 3,
An etching solution characterized in that the fluorine-coordinated ion is an ion containing an element selected from the group consisting of Al, Ti, B, Si, Zr, Fe, Mn, Sn, and Mo. 4. The method according to any one of claims 1 to 3,
An etchant further comprising an oxidizing agent for etching Cu or Cu alloy. The method according to claim 6,
An etching liquid, wherein the oxidant is nitric acid. 4. The method according to any one of claims 1 to 3,
An etching solution further comprising one or two or more acids selected from the group consisting of H ₃ PO ₄ , H ₂ SO ₄ , AcOH, HClO ₄ , HCl and MeSO ₃ H. 4. The method according to any one of claims 1 to 3,
An etchant further comprising one or two or more compounds selected from the group consisting of compounds containing silicide ions and water-soluble silicon compounds containing silicon. A method for producing the etching solution according to any one of claims 1 to 3 by mixing an acid containing fluorine or a fluorine compound for generating the acid with ions which can be coordinated with fluorine. The method of collectively etching the metal laminated film which consists of Ti or a Ti alloy layer and another metal layer with the etching liquid in any one of Claims 1-3.

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