KR20120055262A - Method of manufacturing oxide semiconductor - Google Patents

Abstract

PURPOSE: An oxide semiconductor manufacturing method is provided to control an amount of hydrates among a powdered compound, thereby stably securing electrical properties. CONSTITUTION: A first compound which includes tin is first heat-treated(S102). A second compound which includes one or more metal elements among zinc, indium, gallium, thallium, and zirconium is second heat-treated. A precursor solution is manufactured by mixing an organic solvent after mixing the heat-treated first and second compounds(S108). A precursor layer is formed by spraying the precursor solution on a substrate(S110). An oxide semiconductor is formed by third heat-treating the precursor layer(S112).

Description

Oxide semiconductor manufacturing method {METHOD OF MANUFACTURING OXIDE SEMICONDUCTOR}

TECHNICAL FIELD The present invention relates to a semiconductor, and in particular, to a method for producing an oxide semiconductor.

Thin film transistors (TFTs) are used in various fields, and in particular, liquid crystal displays (LCDs), organic light emitting diode displays (OLED displays) and electrophoretic displays (electrophoretic). It is used as a switching and driving element in flat panel displays such as displays.

The thin film transistor includes a gate electrode connected to a gate line transferring a scan signal, a source electrode connected to a data line transferring a signal to be applied to the pixel electrode, a drain electrode facing the source electrode, and a source electrode and a drain electrode. It includes a semiconductor that is electrically connected.

Among them, the semiconductor is an important factor in determining the characteristics of the thin film transistor. Silicon (Si) is the most used as such a semiconductor. Silicon is divided into amorphous silicon and polycrystalline silicon according to the crystalline form.Amorphous silicon has a simple manufacturing process, but has low charge mobility, and thus has limitations in manufacturing high performance thin film transistors, and polycrystalline silicon has high charge mobility while crystallizing silicon. Steps are required to complicate manufacturing costs and processes. Oxide semiconductors may be used to compensate for such amorphous silicon and polycrystalline silicon.

Such an oxide semiconductor requires a process of forming a thin film through a heat treatment process after coating in the form of a solution.

At this time, since the inflow of oxygen and moisture in the heat treatment process is essential to combine the metal and oxygen, it is necessary to precisely control their moisture and oxygen amount.

However, most of the metals forming oxide semiconductors are in the form of powders, in which the water contained in the powder is contained in solvents, stabilizers, and other compounds added during the process, and the water that is bound when exposed to air. It is not easy to obtain the electrical properties of the semiconductor required when the reaction occurs to perform a solution process.

Accordingly, the present invention is to provide a semiconductor manufacturing method for easily controlling the moisture of the oxide semiconductor to improve the electrical properties of the semiconductor.

Method of manufacturing an oxide semiconductor according to an embodiment of the present invention comprises the step of first heat-treating a first compound containing a tin element, containing at least one metal element from the group consisting of zinc, indium, gallium, thallium, zirconium Performing a second heat treatment on the second compound, mixing the anhydrous treated first compound, and then mixing the second compound to prepare a precursor solution by mixing an organic solvent, and applying the precursor solution to a substrate to form a precursor layer. And forming an oxide semiconductor by performing a third heat treatment on the precursor layer, wherein the first heat treatment proceeds at a temperature of 100 ° C. or more and a melting point of the first compound, and the second heat treatment is 100 ° C. or more and a melting point or less of the second compound. Proceed at the temperature of.

The mixing ratio of the first compound and the second compound may be mixed in a ratio of 0.2: 1 to 1: 1.

The organic solvent may be an anhydrous treated solvent.

The molarity of the first compound and the second compound in the solution may be 0.01M to 0.1M.

The third heat treatment may be performed at a temperature of 450 ℃ to 550 after proceeding at a temperature of 250 ℃ ~ 350 ℃.

 The solvent may include at least one of isopropanol, dimethylformamide, ethanol, methanol, acetylacetone, and dimethylamine borane in addition to 2-methoxy ethanol. have.

The precursor solution further comprises a solution stabilizer, wherein the solution stabilizer comprises at least one selected from alcohol amine compounds, alkyl ammonium hydroxy compounds, alkyl amine compounds, ketone compounds, acid compounds, base compounds and deionized water. It may include.

The molarity of the first compound and the second compound in the solution may be 0.01M to 0.1M.

Using the oxide semiconductor manufacturing method according to an embodiment of the present invention it is possible to ensure the electrical properties of the oxide semiconductor formed by controlling the amount of hydrate in the compound in the powder state.

1 is a flowchart illustrating a method of manufacturing an oxide semiconductor according to an embodiment of the present invention.
2 is a graph showing the VI characteristics when forming an oxide semiconductor according to the present invention and the prior art.
3 is a layout view of a thin film transistor substrate according to the present invention.
4 is a cross-sectional view taken along the line IV-IV of FIG. 3.
FIG. 5 is a cross-sectional view taken along the line VV of FIG. 3.
6 to 13 are cross-sectional views sequentially illustrating a method of manufacturing the thin film transistor array panel of FIGS. 3 and 4, and are cut along the lines IV-IV and VV of FIG. 3.
14 is a layout view illustrating a structure of a thin film transistor array panel for another liquid crystal display according to another embodiment of the present invention.
FIG. 15 is a cross-sectional view of the thin film transistor array panel of FIG. 14 taken along the line XV-XV.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. Whenever a portion of a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. On the contrary, when a part is "just above" another part, there is no other part in the middle.

Hereinafter, a method of forming an oxide semiconductor according to an embodiment of the present invention will be described.

1 is a flowchart illustrating a method of manufacturing an oxide semiconductor according to an embodiment of the present invention.

First, hydrated tin chloride powder and hydrated zinc acetate powder are prepared (S100), and then heat treatment (S102) is performed on each powder.

The heat treatment is preferably performed at a temperature above the evaporation temperature of water and below the melting point of each powder. Since the melting point of tin chloride is 247 ° C and the melting point of zinc acetate is 180 ° C, it is preferable that the tin chloride proceeds at 100 ° C or higher and 247 ° C or lower, and zinc acetate proceeds at a temperature of 100 ° C or higher and 180 ° C or lower.

Next, the heat-treated tin and the metal powder except tin are mixed in a ratio of 0.2: 1 to 1: 1 to prepare a mixed powder (S106).

In the embodiment of the present invention, a zinc compound is used as a metal powder other than tin, but may include other metals.

The metal other than tin may include at least one of metal compounds of zinc, indium, gallium, thallium and zirconium. They bind at least one or more of the ligand group consisting of citrate, acetate, acetylacetonate, acrylate, chloride, nitrate, and fluoride It may be a compound or a hydrate.

Next, a precursor solution is prepared using anhydrous treated 2-methoxyethanol as an organic solvent in the mixed powder (S108). Anhydrous treatment of 2-methoxy ethanol can be carried out using sodium or the like.

As a solvent of the precursor solution, at least one of isopropanol, dimethylformamide, ethanol, methanol, acetylacetone, and dimethylamine borane, in addition to 2-methoxy ethanol, may be used. It may include.

At this time, the molar concentration of the mixed powder in the solution is preferably 0.01M to 1M.

The precursor solution may further comprise a solution stabilizer. Solution stabilizers may include at least one selected from alcohol amine compounds, alkyl ammonium hydroxy compounds, alkyl amine compounds, ketone compounds, acid compounds, base compounds and deionized water, such as monoethanolamine, di Ethanolamine, triethanolamine, monoisopropylamine, N, N-methylethanolamine, aminoethyl ethanolamine, diethylene glycolamine, 2- (aminoethoxy) ethanol, Nt-butylethanolamine, Nt-butyldiethanolamine It may further comprise at least one selected from tetramethylammonium hydroxide, methylamine, ethylamine, acetylacetone, hydrochloric acid, nitric acid, sulfuric acid, acetic acid, ammonium hydroxide, potassium hydroxide and sodium hydroxide.

The solution stabilizer may be included in the precursor solution to increase the solubility of other components and thus form a uniform thin film. The solution stabilizer may vary in content depending on the type and content of the other components described above, but may be contained in about 0.01Vol% to 30Vol% with respect to the total content of the precursor solution. When the solution stabilizer is contained in the above range, solubility can be increased.

Thereafter, the prepared precursor solution is applied on an insulating substrate such as transparent glass or plastic to form a precursor thin film (S110). The precursor solution may be applied by a method such as spin coating, ink jet printing, dip coating, or the like.

Next, an oxide semiconductor thin film is formed by performing heat treatment on the precursor thin film of the substrate (S112).

The heat treatment may be performed by a first heat treatment for removing a solvent included in the precursor thin film and a second heat treatment for forming an oxide semiconductor by reacting metal and oxygen included in the precursor thin film.

The first heat treatment is preferably performed at a temperature of 250 ° C to 350 ° C, and the second heat treatment is performed to a heat treatment of 450 ° C to 550 ° C.

2 is a graph showing the V-I characteristics when an oxide semiconductor is formed in accordance with the present invention and the prior art with a ratio of tin and zinc of 1: 1.

Referring to FIG. ₂ , when the semiconductor is formed of SnCl ₂ containing no moisture, an ideal VI graph is formed as shown in a black graph. However, when the semiconductor is formed of SnCl2 in the hydrate state, an abnormal VI graph is formed as shown in the red graph, indicating that the electrical characteristics of the semiconductor are deteriorated.

It is ideal to form a semiconductor with SnCl ₂ that does not contain water, but the metal compound in powder form easily reacts with water in the air, and most of the hydrate state is present. Therefore, when the semiconductor is formed in such a hydrate state, the electrical characteristics of the semiconductor cannot be obtained. However, as in the embodiment of the present invention, the annealing process for each powder may be performed to obtain VI characteristics similar to black graphs (see green graphs) representing ideal VI characteristics.

A thin film transistor array panel for a liquid crystal display device and a manufacturing method thereof will be described using the method for forming the oxide semiconductor according to the present invention described above.

3 is a layout view of a thin film transistor substrate according to the present invention, FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 3, and FIG. 5 is a cross-sectional view taken along line V-V of FIG. 3.

3 to 5, a gate line 121 is formed on the transparent substrate 110.

The gate line 121 transmits a gate signal and mainly extends in a horizontal direction, and includes a wide end portion 129 for connection with another layer or an external driving circuit.

The gate line 121 is made of copper (Cu) and may be formed by sputtering or plating. In the case of forming by a plating method, a seed layer may be formed under the copper layer. The seed layer can be formed from Ti, Ni, or the like.

The first interlayer insulating layer 180p is formed on the gate line 121. The first interlayer insulating layer 180p may be formed of an organic insulator to planarize the substrate, and the organic insulator may have photosensitivity, and its dielectric constant is preferably about 4.0 or less.

A gate electrode 124, a storage line 131, and a data line 171 are formed on the first interlayer insulating layer 180p.

The gate electrode 124, the storage electrode line 131, and the data line 171 are preferably made of a refractory metal such as molybdenum, chromium, tantalum, and titanium, or an alloy thereof, and not shown. ) And a low resistance conductive film (not shown). Examples of the multilayer structure include a double film of a chromium or molybdenum (alloy) lower film and an aluminum (alloy) upper film, a molybdenum (alloy) lower film, an aluminum (alloy) intermediate film and a molybdenum (alloy) upper film. However, the data line 171 and the gate electrode 124 may be made of various other metals or conductors.

The data line 171 transmits a data voltage and mainly extends in a vertical direction to intersect the gate line 121 and includes a wide end portion 179 for connection with another layer and an external driving circuit.

The storage electrode line 131 receives a predetermined voltage and extends in parallel with the data line 171 to cross the gate line 121. The storage electrode line 131 includes a storage electrode 133 protruding left and right from the storage electrode line 131.

The storage electrode line 131 may be formed to extend in the horizontal direction together with the gate line 121.

The gate insulating layer 140 is formed on the gate electrode 124, the storage electrode line 131, and the data line 171. The gate insulating layer 140 may be formed of silicon oxide (SiO 2) or silicon nitride (SiN x).

An oxide semiconductor 154 is formed on the gate insulating layer 140. The oxide semiconductor 154 is made of an oxide semiconductor formed by the method of FIG.

A second interlayer insulating layer 180q is formed on the oxide semiconductor 154. The second interlayer insulating layer 180q may be formed of an inorganic material such as silicon nitride and silicon oxide.

The second interlayer insulating layer 180q may include a data line 171 in the first contact hole 185a and the second contact hole 185b exposing the semiconductor 154, the second interlayer insulating layer 180q, and the gate insulating layer 140. And contact holes 184 and 183b exposing the gate electrode 124, and exposing the gate line 121 to the second interlayer insulating layer 180q, the gate insulating layer 140, and the first interlayer insulating layer 180p. A contact hole 183a is formed.

The pixel electrode 191 having the drain electrode 175, the first and second connection portions 83 and 84, and the contact auxiliary members 81 and 82 are formed on the second interlayer insulating layer 180q.

The drain electrode 175 is connected to the oxide semiconductor 154 through the contact hole 185b, and the drain electrode 175 is formed of the same material as the pixel electrode 191 and may be integrally formed.

The first connection portion 83 connects the gate electrode 124 and the gate line 121 through the contact holes 183a and 183b, and the second connection portion 84 connects the data line (via the contact holes 184 and 185a). 171 and the oxide semiconductor 154 are connected.

The gate electrode 124, the second connector 84, and the drain electrode 175 form a thin film transistor (TFT) Q together with the semiconductor 154, and the second connector 84 is formed of the thin film transistor. Used as a source electrode, a channel of the thin film transistor Q is formed in the oxide semiconductor 154 between the second connection portion 84 and the drain electrode 175.

The signal input to the gate line 121 is transmitted to the gate electrode 124 through the first connector 83, and the signal input to the data line 171 is transmitted to the semiconductor 154 through the second connector 84. Delivered. When the gate signal is turned on, the data signal is transferred to the pixel electrode 191 through the second connector 84.

The pixel electrode 191, the first connector 83, the second connector 84, and the contact assistants 81 and 82 may be formed of a transparent conducting oxide such as ITO or IZO. In the embodiment of the present invention, since the semiconductor is formed of an oxide semiconductor, ohmic contact is possible, and the conductive oxide constituting the oxide semiconductor 154 and the pixel electrode 191 may be in direct contact.

The pixel electrode 191 overlaps the storage electrode line 131 and the storage electrode 133 to form a storage capacitor.

In the embodiment of the present invention, the gate line 121 is formed of low-resistance copper, and the first interlayer insulating layer is formed of an organic material to eliminate the step caused by the thickness of the copper layer. In addition, since the first interlayer insulating layer is formed of an organic material, the parasitic cap with the gate line is reduced, thereby reducing the signal delay of the gate line.

In addition, in the embodiment of the present invention, since the gate electrode 124 is formed on the first interlayer insulating layer 180p, the gate electrode 124 may be prevented from being contaminated with the organic material of the first interlayer insulating layer, thereby reducing image quality defects. You can.

Next, a method of manufacturing the thin film transistor array panel will be described with reference to FIGS. 6 to 13 and FIGS. 3 to 5.

6 to 13 are cross-sectional views sequentially illustrating a method of manufacturing the thin film transistor array panel of FIGS. 3 and 4, and are cut along the lines IV-IV and V-V of FIG. 3.

6 and 7, the gate line 121 having the wide end portion 129 is formed on the substrate 10.

The gate line 121 is formed by depositing copper by sputtering and patterning the same. The copper layer may be formed using electrolytic plating or electroless plating or the like. The copper layer is then plated over the seed layer.

8 and 9, an organic material is coated on the gate line 121 to form a first interlayer insulating layer 180p. The first interlayer insulating layer 180p flattens the substrate.

The metal is deposited on the first interlayer insulating layer 180p and then patterned to form a data line 171 having a gate electrode 124, a storage electrode line 131, and a wide end portion 179.

10 and 11, the gate insulating layer 140 is formed on the gate electrode 124, the storage electrode line 131, and the data line 171.

The precursor thin film is formed on the gate insulating layer 140 by coating the precursor solution formed by the manufacturing method of FIG. 1. Then, heat treatment is performed on the precursor thin film to form an oxide semiconductor layer.

As described above, the first heat treatment is performed at a temperature of 250 ° C. to 350 ° C., and the second heat treatment is performed at a temperature of 450 ° C. to 550 ° C.

Next, the oxide semiconductor layer is patterned to form an oxide semiconductor 154.

Next, as shown in FIGS. 12 and 13, a second interlayer insulating film 180q is formed on the oxide semiconductor 154.

First and second contact holes 185a and 185b exposing the semiconductor 154 by etching the second interlayer insulating layer 180q, the gate insulating layer 140, and the first interlayer insulating layer 180p, the data line 171, and the like. Contact holes 184 and 183b exposing the gate electrode 124 and contact holes 183a exposing the gate line 121 are formed.

Next, as shown in FIGS. 3 and 4, the transparent conductive oxide layer is formed on the second interlayer insulating layer 180q and then patterned to contact the pixel electrode 191 connected to the semiconductor 154 through the contact hole 185b. The first connection portion 83 connecting the gate electrode 124 and the gate line 121 through the holes 183a and 183b, and the data line 171 and the semiconductor 154 through the contact holes 184 and 185a. A contact auxiliary member 81 connected to an end portion 129 of the gate line 121 and an end portion 179 of the data line 171 through the second connection portion 84 and the contact holes 181 and 182, respectively. 82).

FIG. 14 is a layout view illustrating a structure of a thin film transistor array panel for another liquid crystal display device according to another exemplary embodiment. FIG. 15 is a cross-sectional view of the thin film transistor array panel of FIG. 14 taken along the line XV-XV.

14 and 15, the gate line 121 is formed on the insulating substrate 110 in the horizontal direction. A portion of the gate line 121 protrudes to form a plurality of gate electrodes 124.

The gate line 121 includes a conductive film made of an aluminum-based metal such as aluminum (Al) or an aluminum alloy. In addition to the conductive film, the gate line 121 may be formed of a physical layer with another material, in particular, indium tin oxide (ITO) or indium zinc oxide (IZO). Multi-layered film including other conductive films made of chromium (Cr), titanium (Ti), tantalum (Ta), molybdenum (Mo) and their alloys (eg, molybdenum-tungsten (MoW) alloys) having good chemical and electrical contact properties. It may have a structure. Examples of the combination of the lower film and the upper film include aluminum / molybdenum or aluminum-neodymium (Nd) / molybdenum.

In addition, the gate line 121 may be formed of copper as shown in FIGS. 3 and 4.

A gate insulating layer 140 is formed on the gate line 121, and an oxide semiconductor 154 is formed on the gate insulating layer 140. The oxide semiconductor 154 is formed using the precursor solution formed by the manufacturing method of FIG.

The data line 171 and the drain electrode 175 are formed on the oxide semiconductor 154 and the gate insulating layer 140.

The data line 171 mainly extends in the vertical direction and crosses the gate line 121. A source electrode 173 extends from the data line 171 toward the drain electrode 175, and the source electrode 173 is formed in a U shape. The drain electrode 175 is surrounded by the source electrode 173.

The data line 171 and the drain electrode 175 may be formed of the same material as the gate line.

The passivation layer 180 is formed on the data line 171, the drain electrode 175, and the exposed oxide semiconductor 154.

The passivation layer 180 includes a contact hole 185 exposing the drain electrode 175, and a pixel electrode 191 made of a transparent material such as IZO or ITO or an opaque metal is formed on the passivation layer 180.

The pixel electrode 191 is connected to the drain electrode 175 through the contact hole 185 to receive a data voltage from the drain electrode 175.

The oxide semiconductor manufacturing method according to the present invention is equally applicable to any device requiring a semiconductor as well as a transistor and a display device including the same. In addition, the present invention is not limited to the structure described in the above embodiments, and can be similarly applied to transistors of any structure such as a top gate and a bottom gate.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of the invention.

81, 82: contact auxiliary member 83, 84: connecting member
110: substrate 121, 129: gate line
124: gate electrode 131: sustain electrode line
133: sustain electrode
140: gate insulating film 154: semiconductor
171, 179: gate line
173: source electrode 175: drain electrode
180: shield
180p: first interlayer insulating film 180q: second interlayer insulating film
181, 182, 183a, 183b, 184, 185, 185a, 185b: contact hole
191: pixel electrode

Claims (8)

First heat treating the first compound including the tin element,
A second heat treatment of the second compound including at least one metal element from the group consisting of zinc, indium, gallium, thallium and zirconium,
Preparing a precursor solution by mixing the heat-treated first compound and the second compound and then mixing an organic solvent,
Applying the precursor solution to a substrate to form a precursor layer,
Third heat treatment of the precursor layer to form an oxide semiconductor
Including,
The first heat treatment is carried out at a temperature of more than 100 ℃ below the melting point of the first compound,
The second heat treatment is carried out at a temperature of more than 100 ℃ below the melting point of the second compound
Oxide Semiconductor Manufacturing Method. In claim 1,
Mixing ratio of the first compound and the second compound is a method of manufacturing an oxide semiconductor mixed in a ratio of 0.2: 1 ~ 1: 1. In claim 2,
And the organic solvent is an anhydrous treated solvent. 4. The method of claim 3,
The molar concentration of the first compound and the second compound in the solution is 0.01M to 0.1M. In claim 1,
The third heat treatment proceeds at a temperature of 250 ℃ ~ 350 ℃ and then proceeds at a temperature of 450 ℃ to 550. In claim 1,

The organic solvent includes at least one of isopropanol, dimethylformamide, ethanol, methanol, acetylacetone, and dimethylamine borane in addition to 2-methoxy ethanol. Oxide Semiconductor Manufacturing Method. In claim 1,
The precursor solution further comprises a solution stabilizer,
Wherein the solution stabilizer comprises at least one selected from alcohol amine compounds, alkyl ammonium hydroxy compounds, alkyl amine compounds, ketone compounds, acid compounds, base compounds, and deionized water. In claim 1,
The molar concentration of the first compound and the second compound in the organic solution is 0.01M to 0.1M.

Images