JP2007141892A - Deposition method, substrate for electronic device, electronic device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal oxide film having good characteristics, and to improve the characteristics of an electronic device. <P>SOLUTION: In manufacturing the electronic device (e.g. TFT section of liquid crystal display apparatus) a film applied with a metal alkoxide used as, for example, a transparent conductive film is formed on a substrate 100, and thermal processing using a thermal source of flames of a gas burner using a mixed gas of hydrogen and oxygen as a fuel is performed to bake the film applied with metal alkoxide and to modify the transparent conductive film (metal oxide film) to be formed. By executing this thermal processing, hydrolysis and polycondensation reactions are promoted by hydroxyl group radicals (OH<SP>*</SP>) and oxygen radicals (O<SP>*</SP>) etc. in or around the flames, a non-reaction portion is reduced and the film quality of the transparent conductive film (metal oxide film) can be improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a film forming method and the like, and more particularly to a method for forming a transparent conductive film (transparent electrode) used for an electronic device substrate.

A transparent electrode used in a transmissive liquid crystal display device is a kind of metal oxide (inorganic oxide). Examples include ITO (indium-tin oxide alloy), IO (indium oxide), tin oxide (SnO ₂ ), and the like.

  As a method of forming such a metal oxide, a film is formed by a vapor phase process such as a PVD (physical vapor deposition) method, a CVD (chemical vapor deposition) method, or a vacuum vapor deposition method. There is a way.

  On the other hand, as a method for forming a metal oxide, there is a production method using a liquid phase process such as a sol-gel method (sol-gel method). In the sol-gel method, a solution of an (organic) metal compound is applied to a substrate, the coating film is dried, and then subjected to a heat treatment (firing) to accelerate the hydrolysis and polycondensation reaction of the metal compound. This is a method of forming a film.

  Such a sol-gel method is advantageous in that the chemical composition is easily controlled and a highly uniform film can be obtained at the molecular level as compared with the film formation by the gas phase process described above. In addition, there are advantages in that the manufacturing cost is low and the film formation efficiency (throughput and productivity) is high.

For example, in the following Patent Document 1 (Japanese Patent Laid-Open No. 2001-143535), a transparent conductive film-forming coating solution contains an organic compound in a hydroxy compound generated from a compound containing indium (In) and tin (Sn) and an organic acid. A technique for forming a transparent conductive film by containing a chelate complex coordinated with a ligand, applying this coating solution, drying it, and baking it is disclosed.
JP 2001-143535 A

  The present inventor is engaged in research and development of electronic devices, and has been intensively studied to improve the characteristics of a transparent electrode (transparent conductive film) by a sol-gel method.

  For example, even if the technique described in Patent Document 1 is used, the film characteristics are not sufficient, such as voids in the film (the film is porous) and defects are likely to occur. As a result, there is a problem that use of the electronic device is restricted depending on the applied electronic device.

  Such a problem is considered to be caused by insufficient hydrolysis of the metal compound. Therefore, it is important to develop a technique for promoting hydrolysis (hydrolysis polycondensation reaction) by other methods and improving film quality.

  An object of the present invention is to provide a metal oxide film having good characteristics. It is another object of the present invention to improve the characteristics of an electronic device (apparatus) by using a metal oxide film with good characteristics.

  In the film forming method of the present invention, the organometallic compound solution applied on the substrate is subjected to a heat treatment using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source to hydrolyze the organometallic compound solution or It has the process of forming the electroconductive film formed by baking the said organometallic compound by accelerating a polycondensation reaction.

  Since the heat treatment was performed using the flame of the gas burner as a heat source in this way, the hydrolysis or polycondensation reaction of the organometallic compound solution can be promoted, and the organometallic compound solution (coating film) is baked and formed. The film quality of the conductive film formed can be improved. Specifically, the unreacted part of the conductive film can be reduced.

  The conductive film is a transparent conductive film.

In the heat treatment, for example, the ratio of hydrogen and oxygen in the mixed gas is set to 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O).

The heat treatment is performed, for example, in a state where the hydroxyl radical (OH ^* ) is richer than when the ratio of hydrogen and oxygen in the mixed gas is 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O). .

The heat treatment is performed, for example, in a state in which the ratio of hydrogen and oxygen in the mixed gas is higher than the stoichiometric composition ratio of water (H ₂ O), which is 2 mol: 1 mol.

The heat treatment is performed in a state in which (a) the hydroxyl radical (OH ^* ) is richer than when the ratio of hydrogen and oxygen in the mixed gas is 2 mol: 1 mol, which is the stoichiometric composition ratio of water (H ₂ O). (B) After the first treatment, the ratio of hydrogen and oxygen in the mixed gas is higher than the stoichiometric composition ratio of water (H ₂ O), which is 2 mol: 1 mol. Second processing performed in the state.

The heat treatment is further performed in (c) a third treatment in which the ratio of hydrogen and oxygen in the mixed gas is larger than 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O). including.

  The heat treatment is performed by scanning the flame of the gas burner relative to the organometallic compound solution applied on the substrate.

  The substrate temperature is adjusted by adjusting the scanning speed of the gas burner.

  The present invention is a substrate for an electronic device having a conductive film formed by using the above film method.

  Moreover, this invention is an electronic device provided with the said board | substrate for electronic devices.

  Moreover, this invention is an electronic device provided with the said electronic device. Here, the “electronic device” means a general device having a certain function provided with the semiconductor memory device according to the present invention, and its configuration is not particularly limited. For example, a computer device including the semiconductor memory device in general Any device that requires a storage device, such as a mobile phone, PHS, PDA, electronic notebook, and IC card, is included.

  In the embodiment of the present invention, the coating film coated with the metal compound solution is baked by using a gas burner using a mixed gas of hydrogen and oxygen as a fuel, and then fired, and the formed metal oxide is oxidized. The product is modified.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same or related code | symbol is attached | subjected to what has the same function, and the repeated description is abbreviate | omitted.

1) Electronic Device Manufacturing Apparatus First, an electronic device manufacturing apparatus used for manufacturing an electronic device according to the present embodiment will be described with reference to FIGS.

  FIG. 1 is a diagram illustrating a configuration example of an electronic device manufacturing apparatus used for manufacturing an electronic device according to the present embodiment. In FIG. 1, pure water is stored in a water tank 11, and water is supplied to an electrolysis tank (electrolysis device) 12. Water is electrolyzed by the electrolysis tank 12 and separated into hydrogen gas and oxygen gas. The separated hydrogen gas and oxygen gas are supplied to the gas controller 15. The gas controller 15 includes a computer system, a pressure regulating valve, a flow rate adjusting valve, various sensors, and the like. The supply amount of hydrogen gas and oxygen gas (mixed gas) supplied to the downstream gas burner 22 according to a preset program, Adjust supply pressure, mixing ratio of both gases, etc.

Further, the gas controller 15 further introduces hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) supplied from a gas storage tank (not shown) into the aforementioned mixed gas and supplies it to the gas burner 22. Thereby, the mixing ratio (mixing ratio) of hydrogen and oxygen in the mixed gas is shifted from the stoichiometric composition ratio (H ₂ : O ₂ = 2 mol: 1 mol) of water (H ₂ O), and hydrogen excess (hydrogen rich) or An oxygen-rich (oxygen-rich) mixed gas is obtained.

The gas controller 15 can further introduce an inert gas such as argon (Ar), helium (He), nitrogen (N ₂ ), etc., supplied from a gas storage tank (not shown) into the mixed gas. Thereby, the flame temperature (combustion temperature) and flame state of the gas burner 22 are controlled.

  The water tank 11, the electrolysis tank 12, and the gas controller 15 described above constitute a fuel (raw material) supply unit.

  A chamber (processing chamber) 21 that forms a closed space is disposed downstream of the gas controller 15. In the chamber 21, a gas burner 22 for generating a heat treatment flame, a stage substrate 51 on which a processing target substrate (semiconductor substrate, glass substrate, etc.) 100 is placed and movable relative to the gas burner 22, etc. Is arranged.

  The atmosphere in the chamber 21 is not limited to this. For example, the internal pressure can be set to atmospheric pressure to about 0.5 MPa, and the internal temperature can be set to room temperature to about 100 ° C. In order to keep the atmospheric pressure in the chamber 21 in a desired state, the aforementioned inert gas such as argon can be introduced into the chamber 21.

  The stage unit 51 is provided with a mechanism for moving a table on which a substrate is placed at a constant speed to prevent particles. In addition, in order to prevent a heat shock of the substrate 100 due to a sudden temperature difference or the like, a mechanism for heating (preheating) or cooling is provided on the mounting table of the substrate 100, and this temperature control is performed by an external temperature adjustment unit 52. Made. An electric heater mechanism is used for heating, and a cooling mechanism using cooling gas or cooling water is used for cooling.

  FIG. 2 is a plan view illustrating a configuration example of a gas burner unit of the electronic device manufacturing apparatus. As shown in FIG. 2, the gas burner 22 of the electronic device manufacturing apparatus of FIG. 1 is formed by a longitudinal member that is larger than the width of the stage portion 51 (the vertical direction in the drawing), and generates a flame having a width wider than the width of the stage portion 51. Can radiate. The gas burner 22 is configured to scan the substrate 100 by moving the stage unit 51 in a direction orthogonal to the longitudinal direction of the gas burner 22 (arrow direction in the figure) or by moving the gas burner 22. ing.

  FIG. 3 is a cross-sectional view illustrating a configuration example of a gas burner unit of the electronic device manufacturing apparatus. As shown in FIG. 3, the gas burner 22 includes a gas guide tube 22a provided with a gas outlet hole for leading the mixed gas to the combustion chamber, a shield 22b surrounding the guide tube 22a, and a gas mixture surrounded by the shield 22b. The combustion chamber 22c is combusted, the nozzle 22d is an outlet through which the combustion gas exits from the shield 22b, the mixed gas outlet 22e provided in the air guide tube 22a, and the like.

If the gap (distance) between the nozzle 22d and the substrate 100 is set wide, the pressure decreases when the combustion gas is discharged from the nozzle. If the gap between the nozzle 22d and the substrate 100 is set so as to close (squeeze), the pressure drop of the combustion gas is suppressed and the pressure increases. Therefore, the gas pressure can be adjusted by adjusting the gap. Water vapor annealing, hydrogen rich annealing, oxygen rich annealing, etc. can be promoted by pressurization. Various types of annealing can be selected by setting the mixed gas. In the figure, the state of ejection of water vapor (H ₂ O vapor) is shown.

  As will be described later, by forming a plurality of gas outlets 22e or a linear shape, the flame (torch) shape of the combustion chamber 22c of the gas burner 22 is linear (long flame), a plurality of torch shapes, etc. Can be. The temperature profile in the vicinity of the gas burner 22 is preferably set to be rectangular in the flame scanning direction by the design of the outlet 22e and the nozzle 22d of the shield 22b.

  FIG. 4 is a diagram illustrating a first configuration example of the gas burner unit of the electronic device manufacturing apparatus. 4A is a sectional view of the gas burner 22 in the short direction, FIG. 4B is a partial sectional view of the gas burner 22 in the longitudinal direction, and FIG. 4C schematically shows the gas burner portion. It is a sketch. In these drawings, parts corresponding to those in FIG.

  In this example, a shield 22b is formed so as to surround the air guide tube 22a. A nozzle 22d is provided below the shield 22b, and a gas outlet 22e is provided in a linear shape (long hole) below the air guide tube 22a (on the nozzle 22d side). In addition, in order to make the outflow amount of each site | part of the linear gas outflow port 22e the same, you may make it change the width | variety of a hole according to a place.

  FIG. 5 is a diagram illustrating a second configuration example of the gas burner unit of the electronic device manufacturing apparatus. The other structural example of the gas burner 22 is shown. 5A is a cross-sectional view of the gas burner 22 in the short direction, and FIG. 5B is a partial cross-sectional view of the gas burner 22 in the longitudinal direction. In both figures, parts corresponding to those in FIG.

  In this example, a shield 22b is formed so as to surround the air guide tube 22a. A nozzle 22d is provided below the shield 22b, and a plurality of gas outlets 22e are provided at equal intervals below the air guide tube 22a (on the nozzle 22d side). In this configuration, in order to make the gas density in the combustion chamber uniform and the flow rate of gas flowing from the nozzle 22d to the outside uniform, the air guide tube 22a can be appropriately moved in the left-right direction in the figure, for example. In addition, in order to fix the air guide tube 22a and make the outflow amount of each part of the gas outlet port 22e the same, the interval of the gas outlet port 22e may be changed depending on the location if necessary.

  FIG. 6 is a diagram illustrating a third configuration example of the gas burner unit of the electronic device manufacturing apparatus. 6A is a cross-sectional view of the gas burner 22 in the short direction, and FIG. 6B is a partial cross-sectional view of the gas burner 22 in the longitudinal direction. In both figures, parts corresponding to those in FIG.

  Also in this example, the shield 22b is formed so as to surround the air guide tube 22a. Below the shield 22b is a nozzle 22d, and a plurality of gas outlets 22e are spirally provided at equal intervals on the side surface of the air guide tube 22a. In this configuration, in order to make the gas density in the combustion chamber uniform and the flow rate of gas flowing from the nozzle 22d to the outside uniform, the air guide tube 22a is configured to be rotatable as indicated by the arrows in the figure.

  FIG. 7 is a diagram showing the relationship between the height of the nozzle and the pressure of the outflow gas. As shown in FIG. 7A, the pressure of the outflowing combustion gas can be lowered by separating the nozzle 22d from the surface of the substrate 100. Further, as shown in FIG. 7B, the pressure of the outflowing combustion gas can be increased by bringing the nozzle 22d closer to the surface of the substrate 100.

  FIG. 8 is a diagram showing the relationship between the shape and angle of the nozzle and the pressure of the outflow gas. As shown in FIG. 8, the outflow gas pressure can be adjusted by adjusting the shape and posture of the nozzle 22d (for example, adjusting the shape of the outlet and the angle with respect to the substrate). In this example, as shown in FIG. 8A, the shape of the outlet of the nozzle 22d is open to one side. For this reason, when the gas burner 22 is upright, the pressure of the outflowing combustion gas can be lowered. Further, as shown in FIG. 8B, when the gas burner 22 is rotated or inclined, the outlet of the nozzle 22d approaches the surface of the substrate 100, and the pressure of the outflowing combustion gas can be increased.

  FIG. 9 is a diagram illustrating the relationship between the distance between the nozzle and the air guide tube and the pressure of the outflow gas. As shown in FIG. 9, the temperature of the combustion gas flowing out from the nozzle 22d can be adjusted by changing the relative positional relationship between the air guide tube 22a and the shield 22b. For example, it is possible to change the distance between the heat source and the nozzle 22d by moving the combustion chamber 22c so that the air guide tube 22a can move forward and backward in the shield 22b toward the nozzle 22d. In addition, the distance between the heat source and the substrate can be adjusted.

  Therefore, as shown in FIG. 9A, when the air guide tube 22a is relatively close to the nozzle 22d, the combustion gas flowing out from the nozzle 22d becomes relatively high in temperature. Further, as shown in FIG. 9B, when the air guide tube 22a is relatively separated from the nozzle 22d, the combustion gas flowing out from the nozzle 22d has a relatively low temperature.

  Such a structure makes it possible to adjust the temperature of the outflowing combustion gas without changing the gap between the gas burner 22 and the substrate 100, and is good. Of course, the substrate temperature may be adjusted by changing the gap between the gas burner 22 and the substrate. Of course, the gas temperature can be adjusted by changing the gap between the gas burner 22 and the substrate and further adjusting the relative positional relationship between the air guide tube 22a and the shield 22b. Further, the substrate temperature can be adjusted by changing the scanning speed of the gas burner 22 with respect to the substrate.

  The structure of the gas burner shown in FIGS. 4 to 9 can be combined as appropriate.

  For example, the configuration shown in FIG. 7 and the configuration shown in FIG. 9 can be combined. The entire gas burner 22 shown in FIG. 7 is configured to approach or separate from the substrate 100 so that the gap between the nozzle 22d and the substrate 100 can be adjusted, and the temperature (for example, the surface temperature) of the substrate 100 is adjusted. Further, as shown in FIG. 9, the temperature of the substrate 100 is finely adjusted by allowing the air guide tube 22a in the gas burner 22 to advance and retract toward the nozzle 22d. This makes it easier to set the temperature of the substrate 100 to the target heat treatment temperature.

  Further, the configurations shown in FIGS. 7 and 8 can be combined. The gap between the nozzle 22d and the substrate 100 can be adjusted so that the entire gas burner 22 approaches or separates from the substrate 100 (see FIG. 7), and the surface temperature of the substrate 100 and the flame pressure are adjusted. Further, the surface temperature of the substrate 100 and the flame pressure are adjusted by adjusting the attitude of the entire gas burner 22 relative to the substrate 100 (see FIG. 8).

  Further, the configurations shown in FIGS. 7, 8, and 9 can be combined. The gas burner 22 as a whole is moved closer to or away from the substrate 100 so that the gap between the nozzle 22d and the substrate 100 can be adjusted, and the surface temperature of the substrate 100 and the flame pressure are roughly adjusted (see FIG. 7). Further, the flame pressure on the surface of the substrate 100 is adjusted by adjusting the posture of the gas burner 22 with respect to the substrate 100 (see FIG. 8). Further, the surface temperature of the substrate 100 is finely adjusted by enabling the air guide tube 22a in the gas burner 22 to advance and retract toward the nozzle 22d (see FIG. 9). With this configuration, more accurate heat treatment can be performed.

  Although not shown, the shielding plate 22b of the gas burner 22 can be made movable so that the opening (outlet, aperture) of the nozzle 22d can be changed in a wide or narrow direction in the scanning direction of the gas burner 22. Thereby, it is possible to adjust the exposure time of the portion to be processed of the substrate 100 in the scanning direction of the gas burner 22, the temperature profile of the heat treatment of the substrate 100, the heat treatment temperature, the flame pressure, and the like.

  Since the electronic device manufacturing apparatus described above includes a long gas burner that crosses the substrate, heat treatment of a large-area substrate such as a window glass can be performed. Further, since hydrogen and oxygen as fuel can be obtained by electrolysis of water, it is easy to obtain a gas material and the running cost is low.

  In the heat treatment step, a reducing atmosphere (hydrogen rich) or an oxidizing atmosphere (oxygen rich) can be easily set by appropriately setting the mixing ratio and supply amount of hydrogen and oxygen. It is easy to adjust the flame temperature. Further, an inert gas can be introduced if necessary, or the flame state (temperature, gas pressure, etc.) can be adjusted by adjusting the flow rate of the raw material gas.

  Further, it is easy to obtain a desired temperature profile by adjusting the nozzle shape of the gas burner.

2) Manufacturing method of electronic device (example of application to transparent electrode)
Next, the manufacturing method of the electronic device (liquid crystal display device) using the electronic device manufacturing apparatus mentioned above is demonstrated.

  First, a configuration of an active matrix drive type transmissive liquid crystal display device will be described. FIG. 10 is a configuration diagram of an active matrix drive type transmissive liquid crystal display device. As shown in FIG. 10A, the device 1000 includes a liquid crystal panel 1020 and a backlight 1060. The apparatus 1000 can display an image by transmitting light from the backlight 1060 to the liquid crystal panel 1020.

  The liquid crystal panel 1020 includes a first substrate 1220 and a second substrate 1230 that are arranged to face each other, and a sealing material (not shown) is interposed between these substrates so as to surround the display region. Is provided. Further, a space surrounded by the substrate and the sealing material is filled with liquid crystal that is an electro-optical material, and a liquid crystal layer 1240 is formed. Although not shown, alignment films are provided on the upper and lower surfaces of the liquid crystal layer. This alignment film regulates the alignment direction of the liquid crystal molecules filled in the liquid crystal layer 1240.

  In addition, the first substrate 1220 and the second substrate 1230 are made of a transparent insulating material (eg, a glass substrate), and the upper surface (the liquid crystal layer 1240 side) of the first substrate 1220 has a matrix shape. Are provided with a plurality of pixel electrodes 1223, a scanning line 1224 extending in the X direction, and a signal line 1228 extending in the Y direction.

  Each pixel electrode 1223 is formed of a transparent conductive film having transparency (light transmittance), and is connected to the scanning line 1224 and the signal line 1228 through one thin film transistor (TFT) T, respectively.

  Note that in this embodiment mode, the electronic device substrate of the present invention is formed using the first substrate 1220, the pixel electrode 1223, the scanning line 1224, the signal line 1228, and the thin film transistor T described in detail later. The FIG. 10B is a partially enlarged plan view of one thin film transistor T and a pixel electrode 1223 portion.

  Next, a method for manufacturing the electronic device (liquid crystal display device) of the present embodiment will be described with reference to FIGS. Here, for easy understanding, description will be made with reference to a cross section of the thin film transistor T portion of FIG. 11 and 12 are process cross-sectional views illustrating a method for manufacturing the TFT portion of the liquid crystal display device of the present embodiment.

  First, as shown in FIG. 11A, for example, a silicon oxide film is used as a base protective film (base oxide film, base insulating film) 101 on a glass substrate (quartz substrate, substrate, transparent substrate, insulating substrate) 100. About 100 nm is formed. This silicon oxide film is formed by using, for example, a plasma CVD (chemical vapor deposition) method using TEOS (tetraethyl orthosilicate), oxygen gas, or the like as a source gas.

Next, for example, a silicon film 102 is formed as a semiconductor film on the base protective film (base oxide film, base insulating film) 101. This silicon film is formed by, for example, a CVD method using SiH ₄ (monosilane) gas. Next, the silicon film is subjected to heat treatment, and the silicon is recrystallized to form a polycrystalline silicon film (102).

  Next, a photoresist film (not shown) (hereinafter simply referred to as “resist film”) is formed on the silicon film 102, and is exposed and developed (photolithography) to form an island-like resist film (mask film, resist mask). ). Next, using the resist film as a mask, the silicon film 102 is etched to form a semiconductor element region (island region). Hereinafter, this photolithography, etching, and the process of removing a resist film described later are referred to as patterning.

  Next, the resist film is removed by, for example, ashing (ashing), and a silicon oxide film, for example, is formed as a gate insulating film 103 on the silicon film 102 as shown in FIG. This silicon oxide film is formed by plasma CVD using, for example, TEOS and oxygen gas as source gases.

  Next, a metal material such as Al (aluminum) is formed as the conductive film 104 on the gate insulating film 103 by, for example, a sputtering method. Next, the conductive film 104 is patterned into a desired shape, and a gate electrode (gate electrode wiring) G is formed. As the conductive film 104, a refractory metal such as Ta (tantalum) may be used in addition to Al.

Next, source and drain regions 104a and 104b are formed by implanting (doping or implanting) impurity ions into the silicon film 102 using the gate electrode G as a mask. Note that one of 104a and 104b serves as a source region and the other serves as a drain region. Impurity ions are, for example, PH ₃ (hydrogen phosphide) when forming an n-type semiconductor layer, and B ₂ H ₆ (diborane) when forming a p-type semiconductor layer, for example. Ion implantation.

  Next, as illustrated in FIG. 12A, an interlayer insulating film 105 is formed over the gate electrode G. The interlayer insulating film 105 is made of, for example, a silicon oxide film, and is formed by baking a TEOS film or a polysilazane solution. The polysilazane solution is obtained by dissolving polysilazane in an organic solvent.

  Next, as shown in FIG. 12B, the interlayer insulating film 105 is patterned to form contact holes on the source and drain regions 104a and 104b.

  Next, for example, ITO is formed as a transparent conductive film (metal oxide film) 106 on the interlayer insulating film 105 including the inside of the contact hole by the sol-gel method described above. That is, a metal compound solution is applied to a substrate, a coating film is dried, a precursor is formed, and then heat treatment (firing) is performed to promote hydrolysis and polycondensation reaction (dehydration condensation) of the metal compound. Then, a metal oxide film is formed. The transparent conductive film (metal oxide film) 106 becomes source and drain electrodes (source, drain lead electrode, lead wiring) 106a and 106b. For example, the pixel electrode 1223 in FIG.

Examples of the metal compound solution include an organic solvent solution of a metal alkoxide compound. The metal alkoxide compound can be represented by, for example, M (RO) ₄ , where M is a metal element and R is an alkoxide group. An alkoxide (group) is a general term for materials that react with water to become an alcohol (group).

FIG. 13 shows an example of the reaction mechanism of hydrolysis of the metal alkoxide compound. As shown in FIG. 13A, the alkoxide group R of M (RO) ₄ reacts with water to form ROH (alcohol), and a metal hydroxide is formed (FIG. 13B). Next, dehydration is performed by heating or the like, condensation proceeds (FIG. 13C), and a metal oxide (MxOy) is formed (FIG. 13D). Here, although described as a reaction of one kind of metal alkoxide (M (RO) ₄ ), M1 (R1O) ₄ and M2 (R2O) ₄ are used as raw materials, and oxides of metals M1 and M2 (M1 × M2yOz). The reaction proceeds by the same mechanism when forming the metal oxide or when forming three or more metal oxides. Although the coordination number of the alkoxide group is 4 here, there may be other coordination numbers.

  For example, even if the hydrolysis or polycondensation reaction described above is performed by introducing water vapor into the furnace (treatment chamber), unreacted hydroxyl groups or alkoxide groups remain in the film, resulting in deterioration of the film. It is thought to bring. In addition, since the heating (drying and firing) time is long, the reaction at the middle and bottom of the film occurs after the reaction on the surface of the film, so that degassing occurs gradually, and the film becomes porous. Moreover, it is thought that a crack generate | occur | produces. In addition, degassing due to unreacted hydroxyl groups and alkoxide groups in the film can also occur during the heat treatment process after the film forming process. As a result, contamination of the processing chamber and each component of the electronic device due to such degassing may occur.

  Therefore, in the present embodiment, in order to improve the film quality of the transparent conductive film (conductive film with high transmittance) 106 formed by the sol-gel method and reduce degassing contamination in the subsequent steps, the following method is used. A transparent conductive film 106 (for example, ITO) was formed.

  FIG. 14 is a process cross-sectional view illustrating a method for forming the transparent conductive film 106. As shown in FIG. 14A, an organic solvent solution of a metal alkoxide compound is applied onto the interlayer insulating film 105 including the inside of the contact hole by a spin coating method to form a metal alkoxide coating film 106c. The spin coating condition is, for example, about 2000 seconds at 2000 rpm. In addition, you may apply | coat a metal alkoxide solution using the inkjet method.

  Next, the substrate is mounted on a mounting table (hot plate) (not shown), and the plate temperature is controlled so that the substrate upper surface temperature is equal to or lower than the boiling point temperature of the solvent of the solution (for example, 100 ° C.) and heated for about 1 minute. Thus, the metal alkoxide coating film 106c is dried (the solvent is volatilized). Next, the plate temperature is controlled so that the substrate upper surface temperature is about 300 ° C., and heating is performed for about 10 minutes (temporary firing, intermediate firing, first firing). In addition, as for the coating amount of 1 time, 1000 mm or less is desirable in conversion of a film thickness. Therefore, when a film of 1000 mm or more is formed, it is desirable to repeat coating, drying and pre-baking a plurality of times.

Next, as shown in FIG. 14B, the substrate 100 is mounted on the stage unit 51 of FIG. 1, and the heat treatment (flame annealing, final firing, second firing) is performed by scanning the gas burner 22 on the substrate 100. Then, the metal alkoxide coating film 106c is baked, and the formed transparent conductive film 106 is modified. The flame annealing condition is, for example, a substrate top surface temperature of about 500 to 800 ° C. and 5 minutes or less. The substrate upper surface temperature is adjusted by, for example, the scanning speed of the gas burner 22. Here, for example, scanning is performed at a speed of 2 m / sec. The ratio of hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) supplied to the gas burner 22 is, for example, 2 mol: 1 mol which is the stoichiometric composition of water (H ₂ O).

  As described above, according to the present embodiment, since the metal alkoxide coating film is subjected to the flame annealing treatment, the film can be baked in a short time and the film can be modified. The reaction part can be reduced. In addition, the manufacturing cost can be reduced and the film formation efficiency (throughput and productivity) can be improved as compared with the film formation by the vapor phase process described above.

  That is, in the case of heat treatment in a normal furnace, firing for about 30 minutes is necessary even if the temperature in the furnace is set to about 450 to 500 ° C. The processing can be completed in units of several minutes from the second (30 minutes or less).

  Next, the reason why the film characteristics are improved will be described. 15 and 16 are reaction mechanism diagrams schematically showing the hydrolysis of the metal alkoxide coating film of the present embodiment.

  As shown in FIG. 15A, a hydroxyl group is coordinated on the surface of the underlying inorganic material (interlayer insulating film 105), and ROH (alcohol) is removed from the hydroxyl group (OH) and the alkoxide group (R). The metal alkoxide compound is fixed on the surface (FIG. 15B). Further, the de-ROR reaction (dehydration reaction, de-ROH reaction, etc.) proceeds from the fixed metal alkoxide compounds. Such a reaction is performed during coating, drying, and first firing. In addition, although it demonstrated as a de-ROR reaction here, the dehydration reaction and de-ROH reaction which were demonstrated referring FIG. 13 also occur.

  Even in a state where such a polycondensation reaction (de-ROR reaction, dehydration reaction, de-ROH reaction, etc.) has progressed, there are unreacted hydroxyl groups and alkoxide groups as shown in FIG. Therefore, when the above-described flame annealing is performed, the polycondensation reaction is promoted from these unreacted groups, and a good transparent conductive film (metal oxide film) is obtained (FIG. 16B).

That is, according to the inventor's study, oxygen radicals (O ^* ) are present in or around the flame in addition to the raw material gases (O ₂ , H ₂ ) and H ₂ O (water vapor) that is a product of combustion. It is considered that a hydroxyl radical (OH ^* ) exists. These radicals are considered to be generated by, for example, a material gas or water vapor decomposed by the thermal energy of a flame or radicalization of a reaction intermediate.

Such radicals are reactive species and promote the polycondensation reaction of the metal alkoxide compound. Further, such radicals have a smaller molecular size than O ₂ and H ₂ O and are likely to diffuse into the film. Therefore, it is considered that the reaction is promoted at the center and bottom of the membrane. As a result, the unreacted part is reduced and the film quality of the transparent conductive film (metal oxide film) is considered to be improved. The ease of diffusion of these radicals into the film is thought to contribute to the reduction of the processing time described above. In addition, since radicals are excited unstable substances, their reaction speed is fast, which contributes to shortening of processing time.

  It should be noted that since the firing and modification of the film are expected to proceed in parallel, it is difficult to clearly separate these treatments. Flame annealing may be performed.

In the present embodiment, as described above, among the heat treatments including drying, first firing, and second firing, the second firing is the flame annealing treatment, but other drying and first firing are also the flame annealing treatment. Also good. At this time, the flow rate and ratio of hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) supplied to the gas burner 22 may be adjusted as follows. FIG. 17 and FIG. 18 are reaction mechanism diagrams schematically showing how the reactive species participate in the hydrolysis of the metal alkoxide coating film of the present embodiment.

Since the state of the change from the metal alkoxide compound to the metal oxide film is the same as in FIGS. 15 and 16, the description thereof is omitted. As shown in FIG. 17A, it is desirable that the flame annealing in the drying step be performed in a state rich in water vapor (H ₂ O) and hydroxyl radicals (OH ^* ) that directly contribute to hydrolysis. .

For example, in order to make H ₂ O rich, the flow rate of hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) is increased as compared with first firing and second firing described later, or water vapor is directly added to the gas burner 22 separately. A method such as supplying

Further, although the hydroxyl radical is considered to increase depending on the H ₂ O rich condition, the ratio of hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) is further changed to 2 mol which is the stoichiometric composition of water. Even if the composition ratio (ratio, ratio) of oxygen is larger than 1 mol (oxygen-rich), the hydroxyl radical is considered to increase. It is also conceivable to enrich the hydroxyl radical (OH ^* ) by other methods such as changing the type of supply gas or applying excitation energy to the flame from the outside.

Next, flame annealing in the first firing step is performed. In this case, the flow rate of hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) is lowered, or the supply of water vapor is stopped. Further, the ratio of hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) is returned to 2 mol: 1 mol which is the stoichiometric composition of water. That is, normal flame annealing is performed. In addition, you may abbreviate | omit the flame annealing of this 1st baking step.

Next, in the flame annealing of the second firing step, as shown in FIG. 18, oxygen (O ₂ ) and oxygen radicals (O ₂ ^* , O ^* ) that are considered to contribute directly to the polycondensation reaction and the oxidation reaction are generated. It is considered desirable to process in a rich state.

For example, to make oxygen (O ₂ ) and oxygen radicals (O ₂ ^* , O ^* ) rich, the ratio of hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) is the stoichiometric composition of water. A method of increasing the oxygen composition ratio from 2 mol to 1 mol is mentioned. Further, oxygen radicals (O ₂ ^* , O ^* ) may be enriched by other methods.

In addition, when performing each step of drying, 1st baking, and 2nd baking by flame annealing in this way, it can carry out as a series of processes. That is, in the initial stage (first stage) of the flame annealing treatment, various gases supplied to the gas burner 22 are adjusted so that the water vapor (H ₂ O) and hydroxyl radicals are rich, and the middle stage (second stage). ) Is returned to normal conditions, and in the latter period (third period), oxygen (O ₂ ) and oxygen radicals (O ₂ ^* , O ^* ) are supplied to the gas burner 22 so as to be rich. Adjust various gases. The middle term may be omitted.

  As described above, in the present embodiment, in the heat treatment (drying, first and second firing) of the metal alkoxide coating film, supply to the gas burner 22 in consideration of the involvement of the reactive species in the hydrolysis and polycondensation reaction. Since the various gases to be adjusted are adjusted, the reaction is further promoted, the film can be modified, and the unreacted part in the film can be reduced. As a result, the device characteristics can be improved.

In addition, after the above-described series of flame annealing processes is completed (from the third period), hydrogen (H ₂ ) and hydrogen radicals (H ₂ ^* , H ^* ) are brought into a rich state as the fourth process. The various gases supplied to the gas burner 22 are adjusted.

For example, in order to make hydrogen (H ₂ ) and hydrogen radicals (H ₂ ^* , H ^* ) rich, the ratio of hydrogen gas (H ₂ ) and oxygen gas (O ₂ ) is the stoichiometric composition of water. An example is a method in which the composition ratio of hydrogen is larger than 2 mol: 1 mol. The hydrogen radical (H ₂ ^* , H ^* ) may be rich by other methods.

  By performing this treatment, the conductivity of the transparent conductive film (metal oxide) is improved (resistance value is lowered). FIG. 19 is a schematic diagram showing how the resistance of the transparent conductive film is lowered when processing is performed in a state where hydrogen or the like is rich. As shown in FIG. 19A, the carrier density of the transparent conductive film is, for example, in the case of ITO, in addition to the generation of carriers due to tetravalent Sn, the generation of carriers due to oxygen vacancies (oxygen defects) is also possible. concern. Therefore, the resistance is lower when there are more oxygen vacancies while maintaining the film quality.

Therefore, as shown in FIG. 19B, oxygen is extracted (FIG. 19C) by flame annealing in which hydrogen (H ₂ ) and hydrogen radicals (H ₂ ^* , H ^* ) are rich, and the carrier density is increased. This is to increase the resistance.

In addition, as a metal alkoxide compound in the case of forming ITO as a metal alkoxide compound, an organic solvent, and a transparent conductive film (metal oxide) to be formed, trimethoxyindium (In (OCH ₃ ) ₃ ), triethoxyindium ( In (OC ₂ H ₅ ) ₃ ), tri-i-propoxy indium (In (O—I—C ₃ H ₇ ) ₃ , methoxyethoxy indium (In (OCH ₂ CH ₂ OCH ₃ ) _3, etc.). In addition, the transparent conductive film 106 (ITO, TO, FTO, AZO, etc.) can be formed by the sol-gel method described above.

  Next, by patterning the transparent conductive film 106 formed in the above steps, source and drain electrodes (source, drain lead electrode, lead wiring) 106a and 106b are formed (see FIG. 12B). Note that one of 106a and 106b serves as a source electrode, and the other serves as a drain electrode. Alternatively, the source and drain electrodes 106b may be extended to serve as the pixel electrode 1223 (see FIG. 10B).

  Further, the pixel electrode (transparent electrode) 1223 alone may be formed by the method of the present invention. For example, when the pixel electrode (transparent electrode) 1223 is formed using the present invention, a metal alkoxide compound is applied on the source / drain electrode 106b through an interlayer insulating film, for example, as described above, and a flame annealing process is performed. For example, ITO is formed as the transparent conductive film (metal oxide). Thereafter, patterning is performed in a desired shape to form a pixel electrode (transparent electrode) 1223. Note that, for example, ITO may be previously formed as a transparent conductive film (metal oxide) below the source and drain electrodes 106b, and then these may be connected when forming the source and drain electrodes 106b. Further, the present invention may be applied to an electrode facing the pixel electrode 1223 (for example, an electrode formed on the surface of the second substrate 1230). In this case, a metal alkoxide compound is applied on the substrate, and a flame annealing process is performed to form, for example, ITO as a transparent conductive film (metal oxide). Thereafter, patterning is performed as necessary to obtain an electrode (transparent electrode).

  In addition, these electrodes need to have permeability, and are suitable using the transparent conductive film (metal oxide) of the present invention.

  Through the above steps, the TFT (first substrate side) is almost completed. Next, a separately formed second substrate is bonded to the first substrate, and liquid crystal is injected, whereby the liquid crystal display device is almost completed (see FIG. 10A).

  In the present embodiment, a metal alkoxide compound (metal methoxide, ethoxide, propoxide, butoxide, etc. constituting the metal oxide to be formed) is used as the organometallic compound. A compound may be used.

  In this embodiment, the TFT and the pixel electrode are described as an example of the electronic device using the transparent conductive film. However, the present invention is not limited to such a part and can be widely applied to apparatuses using the transparent conductive film. It is.

  In addition to the sol-gel method, the present invention can also be applied to the formation of metal oxides by a MOD (metal organic deconposition) method. The MOD method is a method of forming a metal oxide by applying an organic solvent solution of a metal compound and performing a heat treatment in the same manner as the sol-gel method, but the main reaction is different from the sol-gel method in that the main reaction is thermal decomposition. However, radicals generated by the flame annealing of the present invention are considered to promote such thermal decomposition. Therefore, by using the flame annealing of the present invention for the heat treatment of the MOD method, thermal decomposition is promoted, heat treatment (firing) of the formed film is performed in a short time, and unreacted parts in the film are reduced. The film can be modified.

As described above, the present invention can be widely applied to a film forming method using an organic solvent solution of a metal compound.
<Description of electro-optical device and electronic device>
Next, an electro-optical device and an electronic apparatus in which the electronic device (liquid crystal display device) formed by the method described in the above embodiment is used will be described.

  The aforementioned electronic device (for example, a semiconductor device such as a TFT) is used as, for example, a drive element of an electro-optical device (display device). FIG. 20 shows an example of an electronic apparatus using the electro-optical device of the invention. FIG. 20A shows an application example to a mobile phone, and FIG. 20B shows an application example to a video camera. 20C illustrates an example of application to television (TV), and FIG. 20D illustrates an example of application to roll-up television.

  As shown in FIG. 20A, the mobile phone 530 includes an antenna portion 531, an audio output portion 532, an audio input portion 533, an operation portion 534, and an electro-optical device (display portion) 500. The electro-optical device of the present invention can be used for this electro-optical device.

  As shown in FIG. 20B, the video camera 540 includes an image receiving unit 541, an operation unit 542, an audio input unit 543, and an electro-optical device (display unit) 500. The electro-optical device of the present invention can be used for this electro-optical device.

  As illustrated in FIG. 20C, the television 550 includes an electro-optical device (display unit) 500. The electro-optical device of the present invention can be used for this electro-optical device. The electro-optical device of the present invention can also be used for a monitor device (electro-optical device) used in a personal computer or the like.

  As illustrated in FIG. 20D, the roll-up television 560 includes an electro-optical device (display unit) 500. The electro-optical device of the present invention can be used for this electro-optical device.

  In addition to the above, electronic devices having electro-optical devices include large screens, personal computers, portable information devices (so-called PDAs, electronic notebooks), etc., and fax machines with display functions, digital camera finders, mobile phones, etc. Various types such as a type TV, an electric bulletin board, and an advertising display are included.

The figure which shows the structural example of the electronic device manufacturing apparatus used for manufacture of the electronic device of Embodiment 1. The top view which shows the structural example of the gas burner part of an electronic device manufacturing apparatus Sectional drawing which shows the structural example of the gas burner part of an electronic device manufacturing apparatus The figure which shows the 1st structural example of the gas burner part of an electronic device manufacturing apparatus. The figure which shows the 2nd structural example of the gas burner part of an electronic device manufacturing apparatus. The figure which shows the 3rd structural example of the gas burner part of an electronic device manufacturing apparatus. Diagram showing the relationship between nozzle height and effluent gas pressure The figure which shows the relationship between the shape and angle of the nozzle and the pressure of the outflow gas The figure which shows the relationship between the distance between the nozzle and the air guide tube and the substrate temperature Configuration diagram of transmissive liquid crystal display device of active matrix drive system Process sectional drawing which shows the manufacturing method of the TFT part of the liquid crystal display device of this Embodiment Process sectional drawing which shows the manufacturing method of the TFT part of the liquid crystal display device of this Embodiment The figure which shows an example of the reaction mechanism of a hydrolysis of a metal alkoxide compound Process sectional drawing which shows the formation method of the transparent conductive film 106 Reaction mechanism diagram schematically showing hydrolysis of the metal alkoxide coating film of the present embodiment Reaction mechanism diagram schematically showing hydrolysis of the metal alkoxide coating film of the present embodiment Reaction mechanism diagram schematically showing how the reactive species participate in the hydrolysis of the metal alkoxide coating film of the present embodiment Reaction mechanism diagram schematically showing how the reactive species participate in the hydrolysis of the metal alkoxide coating film of the present embodiment Schematic diagram showing how the resistance of the transparent conductive film is reduced when processing is performed in a rich state of hydrogen, etc. FIG. 10 is a diagram illustrating an example of an electronic apparatus using the electro-optical device of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Water tank, 12 ... Electrolysis tank, 15 ... Gas controller, 21 ... Chamber (processing chamber), 22 ... Gas burner, 22a ... Air conduit, 22b ... Shielding device, 22c ... Combustion chamber, 22d ... Nozzle, 22e ... Outlet 51, stage portion, 100, glass substrate (substrate), 101, base protective film, 102, silicon film, 103 gate insulating film, 104 conductive film, 104a, 104b, source and drain regions, 105 Interlayer insulating film 106c ... polysilazane coating film 106 ... conductive film 106a, 106b ... source and drain electrodes 500 ... electro-optical device 530 ... mobile phone 531 ... antenna part 532 ... audio output part 533 ... audio Input unit, 534 ... operation unit, 540 ... video camera, 541 ... image receiving unit, 542 ... operation unit, 543 ... audio input unit, 550 ... tele John, 560 ... roll-up television, 1000 ... transmission type liquid crystal display device, 1020 ... liquid crystal panel, 1060 ... backlight, 1220 ... first substrate, 1223 ... pixel electrode, 1224 ... scanning line, 1228 ... signal line 1228 1230 ... second substrate 1240 ... liquid crystal layer G ... gate electrode T ... thin film transistor

Claims (12)

A film forming method comprising:
The organometallic compound solution applied on the substrate is subjected to a heat treatment using a flame of a gas burner using a mixed gas of hydrogen and oxygen as a heat source to promote hydrolysis or polycondensation reaction of the organometallic compound solution. A film forming method comprising a step of forming a conductive film formed by firing the organometallic compound.   The film forming method according to claim 1, wherein the conductive film is a transparent conductive film. _2. The film forming method according to claim 1, wherein the heat treatment is performed such that a ratio of hydrogen and oxygen in the mixed gas is 2 mol: 1 mol which is a stoichiometric composition ratio of water (H ₂ O). The heat treatment is performed in a state where the hydroxyl radical (OH ^* ) is richer than when the ratio of hydrogen and oxygen in the mixed gas is 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O). The film forming method according to claim 1, wherein: 2. The heat treatment is performed in a state where the ratio of hydrogen and oxygen in the mixed gas is larger than the stoichiometric composition ratio of water (H ₂ O), which is 2 mol: 1 mol, of oxygen. The film-forming method of description. The heat treatment
(A) First treatment performed in a state where the hydroxyl radical (OH ^* ) is richer than when the ratio of hydrogen and oxygen in the mixed gas is 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O). When,
(B) After the first treatment, the ratio of hydrogen and oxygen in the mixed gas is set to a _second state in which the oxygen composition ratio is larger than 2 mol: 1 mol which is the stoichiometric composition ratio of water (H ₂ O). Processing,
The film forming method according to claim 1, further comprising: The heat treatment further includes
(C) including a third treatment in which the ratio of hydrogen and oxygen in the mixed gas is performed in a state in which the composition ratio of hydrogen is larger than 2 mol: 1 mol, which is the stoichiometric composition ratio of water (H ₂ O). The film forming method according to claim 6.   2. The film forming method according to claim 1, wherein the heat treatment is performed by scanning the flame of the gas burner relative to the organometallic compound solution applied on the substrate.   The film forming method according to claim 8, wherein the substrate temperature is adjusted by adjusting a scanning speed of the gas burner.   The board | substrate for electronic devices which has an electroconductive film formed using the film-forming method of Claims 1-9.   An electronic device comprising the electronic device substrate according to claim 10. An electronic apparatus comprising the electronic device according to claim 11.

Images