JP2016103531A - Thin film transistor, manufacturing method and insulation film thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film transistor which has resistance to an environmental factor and high reliability, and uses an oxide semiconductor as a channel.SOLUTION: A thin film transistor 100 comprises a gate electrode 20, an insulation film 60, a channel 40 having an oxide semiconductor as a main component, a source electrode 52, and a drain electrode 54. The insulation film 60 includes a compound having one or more than two second elements 62 with the lower oxidation reduction potential than the oxidation reduction potential of the first element included in the oxide semiconductor, and the insulation film 60 is brought into contact with the channel 40.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thin film transistor, a method for manufacturing the same, and an insulating film.

  In recent years, there has been an example in which an oxide semiconductor is used as an electrode layer or a channel together with a silicon-based semiconductor material. In research and development of thin film transistors using an oxide semiconductor film as a channel, various measures have been taken so far to solve technical problems peculiar to oxide semiconductors. For example, for an oxide semiconductor stack that is relatively susceptible to environmental factors, the influence of the interface state formed at the interface with the insulating layer in contact with the oxide semiconductor stack may affect the carrier path of the transistor. And / or a separate oxide semiconductor layer that functions as a barrier layer for suppressing the constituent elements of the insulating layer from being mixed into the oxide semiconductor layer. The technique to provide is disclosed (patent document 1).

  In addition, one of the main technical problems when an oxide semiconductor is used as a channel is a change in electrical conductivity due to oxygen deficiency. In general, the oxygen deficiency is likely to change depending on environmental factors and the passage of time after manufacturing a thin film transistor using an oxide semiconductor film as a channel. Therefore, a technique for providing a transistor with stable electric characteristics by supplying oxygen to a transistor including an oxide semiconductor film to compensate for oxygen vacancies in the oxide semiconductor film is disclosed. (Patent Document 2).

JP 2014-57056 A JP 2013-229587 A

  Until now, in order to improve the characteristics of an oxide semiconductor as a channel of a thin film transistor, means for protecting the oxide semiconductor as a channel from environmental factors disclosed in Patent Document 1, or disclosed in Patent Document 2 Means for actively supplying oxygen to an oxide semiconductor and suppressing oxygen vacancies have been mainly employed.

  However, in order to realize the technique described in Patent Document 1, for example, it is necessary to employ a process that requires a considerably expensive and large-scale facility such as a film forming apparatus that requires a high degree of vacuum. In order to realize the technique described in Patent Document 2, the oxide insulating film is covered so that oxygen does not diffuse from the oxide insulating film which is a supply source of oxygen to the channel into a region other than the channel. It is necessary to provide an oxygen barrier film separately.

  On the other hand, while paying attention to layers other than the channel employed in the thin film transistor, the action of stabilizing the interface between the oxide semiconductor that is the active layer and the layer by the components contained in the layer, There is still not enough research or development on approaches to solve various technical problems.

  A thin film transistor in which an oxide semiconductor is used as a channel or an active layer is a semiconductor device including various active matrix elements, display elements, or electro-optical elements, or a microelectromechanical system (hereinafter collectively referred to as “solid-state electronic element”). Is also expected to be applied.

  The present invention solves at least one of a plurality of technical problems of an oxide semiconductor as a channel or an active layer, so that the oxide semiconductor has an environmental factor (for example, water molecules, light (including ultraviolet rays)). , Resistance to at least one selected from the group of reducing gas and heat), or can greatly contribute to the realization of a thin film transistor with high reliability. Typically, the present invention greatly contributes to improvement or reliability of various characteristics of a thin film transistor including the oxide semiconductor, in particular, electrical characteristics or reliability, and simplification of a manufacturing process of the thin film transistor.

  The inventors of the present application, in a thin film transistor including an oxide semiconductor channel or active layer that can be widely used as a solid-state electronic device, based on the knowledge that the oxide semiconductor is easily affected by weather resistance, various characteristics of the thin film transistor, In particular, intensive research was conducted to improve the electrical characteristics and to simplify the manufacturing process of the thin film transistor.

  As a result of repeated research and analysis by the inventors, a plurality of technical characteristics of an oxide semiconductor are obtained by focusing on a film having an insulating property in contact with the oxide semiconductor as a channel or an active layer employed in a thin film transistor. It has been found that at least one of the problems can be solved. Specifically, the inventors have determined that the insulating film has the effect of strengthening the oxide semiconductor, in other words, increasing the weather resistance of the oxide semiconductor. It has been found that the film can be replaced with some of the films provided in known thin film transistors. The present invention was created based on the above viewpoint.

  One thin film transistor of the present invention includes a gate electrode, an insulating film, a channel containing an oxide semiconductor as a main component, a source electrode, and a drain electrode. In addition, the insulating film includes a compound having one or more second elements having a redox potential lower than the redox potential of the first element included in the oxide semiconductor, and The insulating film is in contact with the above-described channel.

  This thin film transistor includes a channel whose main component is an oxide semiconductor containing a first element. In addition, a compound having one or more second elements having a redox potential lower than the standard redox potential of the first element described above (also simply referred to as “redox potential” in the present application) is included. An insulating film is in contact with the aforementioned channel. Therefore, at least in the interface region between the channel and the insulating film, a redox potential is lower than that of the first element, that is, due to the presence of the second element that is more difficult to reduce, between the metal and oxygen in the oxide semiconductor or on the surface. In other words, the possibility of strengthening the binding force increases. Then, oxygen vacancies in the oxide semiconductor are suppressed or prevented, so that various characteristics, in particular, electrical characteristics and / or reliability of a thin film transistor including the oxide semiconductor can be realized.

  One manufacturing method of a thin film transistor of the present invention is a manufacturing method of a thin film transistor including a gate electrode, an insulating film, a channel containing an oxide semiconductor as a main component, a source electrode, and a drain electrode. In addition, the method for manufacturing the thin film transistor includes the compound having one or more second elements having a redox potential lower than the redox potential of the first element contained in the oxide semiconductor. The insulating film is arranged so as to be in contact with the above-described channel.

  This method for manufacturing a thin film transistor is a method for manufacturing a thin film transistor having a channel whose main component is an oxide semiconductor containing a first element. In addition, in the method for manufacturing the thin film transistor, an insulating film containing a compound having one or more second elements having a redox potential lower than the redox potential of the first element is provided in the channel. The arrangement | positioning process arrange | positioned so that it may contact | connect is provided. Therefore, at least in the interface region between the channel and the insulating film, a redox potential is lower than that of the first element, that is, due to the presence of the second element that is more difficult to reduce, between the metal and oxygen in the oxide semiconductor or on the surface. This increases the possibility that the bond strength will be strengthened. Then, oxygen vacancies in the oxide semiconductor are suppressed or prevented, which can contribute to improvement of various characteristics, particularly electrical characteristics and / or reliability of a thin film transistor including the oxide semiconductor. In addition, due to the arrangement of the insulating film that realizes the above-described action by the second element, for example, at least one selected from the group of conventionally employed gate insulating films, passivation films, etch stop films, and organic films This film can be replaced with the aforementioned insulating film. As a result, according to this thin film transistor manufacturing method, there is provided a manufacturing method excellent in industrial and mass productivity that realizes simplification of the manufacturing process while realizing suppression or prevention of oxygen deficiency in the oxide semiconductor. be able to.

  One insulating film of the present invention is an insulating film in contact with a channel mainly including an oxide semiconductor in a thin film transistor and lower than the redox potential of the first element contained in the oxide semiconductor. A compound having one or more second elements having a redox potential is included.

  This insulating film is an insulating film included in a thin film transistor having a channel whose main component is an oxide semiconductor containing the first element. In addition, the insulating film is in contact with the above-described channel, and the insulating film has one or more second elements having a redox potential lower than the redox potential of the first element. Is included. Therefore, when this insulating film is employed, an oxide semiconductor is present due to the presence of the second element having a lower oxidation-reduction potential than that of the first element, that is, more difficult to be reduced, at least in the interface region between the channel and the insulating film. This increases the possibility that the inner or surface metal-oxygen bonding force is strengthened. Then, since oxygen vacancies in the oxide semiconductor are suppressed or prevented, the insulating film contributes to improvement of various characteristics of the thin film transistor including the oxide semiconductor, particularly electrical characteristics and / or reliability. obtain.

  Incidentally, in the present application, the first element is not necessarily limited to one metal element, and may include a plurality of metal elements. Further, the second element is not necessarily limited to one metal element, and may include a plurality of metal elements. From the viewpoint of accurately suppressing or preventing oxygen vacancies in the oxide semiconductor containing the first element, the second element contains the plurality of metal elements and the second element contains the plurality of metal elements. It is preferable that at least one metal element of the elements has a lower redox potential than a metal element having the lowest redox potential among the plurality of metal elements as the first element. In addition, when the first element includes a plurality of metal elements and the second element includes a plurality of metal elements, the metal element having the highest oxidation-reduction potential among the plurality of metal elements as the second element. More preferably, the redox potential is lower than the redox potential of the metal element having the lowest redox potential among the plurality of metal elements as the first element. In the present application, the ordinal numbers of the “first element” and the “second element” are merely representations for convenience used to distinguish each other. Therefore, there is no superiority or inferiority between the “first element” and the “second element”.

  In the present application, the thickness of the “thin film” is not particularly limited, but a film having a thickness of 1 nm to 5 μm typically corresponds to the “thin film”. Further, in the present application, “film” is also expressed as “layer”. Therefore, in the present application, the expression “film” includes the meaning of “layer”.

  In one thin film transistor of the present invention, oxygen vacancies in the oxide semiconductor in a channel containing the oxide semiconductor containing the first element as a main component are suppressed or prevented. Improvement and / or improvement in reliability can be realized. In addition, according to one thin film transistor manufacturing method of the present invention, a manufacturing method excellent in industriality or mass productivity that realizes simplification of a manufacturing process while realizing suppression or prevention of oxygen deficiency in the oxide semiconductor. Can be provided. In addition, one insulating film of the present invention includes a compound having one or more second elements having a redox potential lower than the redox potential of the first element in the insulating film. Therefore, it can contribute to improvement of various characteristics, particularly electrical characteristics and / or reliability of a thin film transistor including a channel whose main component is an oxide semiconductor containing the first element.

It is a cross-sectional schematic diagram of the thin-film transistor in 1st Embodiment. It is an enlarged view (imaginary figure) of the X area | region of FIG. It is another enlarged view (imaginary figure) of the X area | region of FIG. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin-film transistor in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin-film transistor in 1st Embodiment. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin-film transistor in 1st Embodiment. It is a cross-sectional schematic diagram of the thin-film transistor in 2nd Embodiment. It is a cross-sectional schematic diagram of the thin-film transistor in 3rd Embodiment. It is a cross-sectional schematic diagram of the thin-film transistor in 4th Embodiment. It is a cross-sectional schematic diagram of the thin-film transistor in 5th Embodiment. It is a cross-sectional schematic diagram of the thin-film transistor in 6th Embodiment.

  DESCRIPTION OF EMBODIMENTS A conductor precursor solution, a conductor thin film, a solid electronic device, and a method for manufacturing the same according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this description, common parts are denoted by common reference symbols throughout the drawings unless otherwise specified. In the drawings, elements of the present embodiment are not necessarily described with each other kept to scale. Further, some symbols may be omitted to make each drawing easier to see.

  Hereinafter, a configuration of a thin film transistor 100 as an example of a solid-state electronic device in the present embodiment and a manufacturing method thereof will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view of a thin film transistor 100 of this embodiment. 2 and 3 are enlarged views (imaginary views) of the X region of FIG. 4 to 6 are schematic cross-sectional views showing one process of the method for manufacturing the thin film transistor 100 in the present embodiment.

  Note that the thin film transistor 100 of the present embodiment employs a so-called bottom gate structure, but the present embodiment is not limited to this structure. Therefore, a person skilled in the art can form the top gate structure by changing the order of the steps by referring to the description of the present embodiment with ordinary technical common sense. The thin film transistor 100 of this embodiment employs a so-called top contact structure in which a source electrode 52 and a drain electrode 54 are provided above a channel 40 mainly composed of an oxide semiconductor. It is not limited to such a structure. Accordingly, those skilled in the art can form the bottom contact structure by changing the order of the steps by referring to the description of the present embodiment with ordinary technical common sense. In addition, the temperature display in the present application represents the set temperature of the calibrated heater.

[Configuration of thin film transistor]
As shown in FIG. 1, the thin film transistor 100 according to the present embodiment includes, as an example, Al, Mo, and the like on one substrate 10 selected from the group of various glass substrates, various resin substrates, and various semiconductor substrates. A gate electrode 20 made of Ti, W, Cu, Nb, Mn, Mg or an alloy thereof, for example, a gate insulating film 30 made of silicon oxide or silicon nitride, as an example, and an oxide semiconductor containing a first element described later as a main component. A channel 40, an example of which is a source electrode 52 and a drain electrode 54 made of Al, Mo, Ti, W, Cu, Nb, Mn, Mg, or an alloy thereof, an insulating film 60 containing a second element 62 described later, and an example A lead electrode 70 made of ITO (indium tin oxide) is provided. In the thin film transistor 100 shown in FIG. 1, a contact hole penetrating a part of the insulating film 60 is formed in order to form the extraction electrode 70 that is electrically connected to the drain electrode 54. However, although not shown in FIG. 1, a contact hole of the insulating film 60 for the source electrode 52 may be formed in the same manner as the drain electrode 54.

  Further, the representative thickness of the gate electrode 20 in the thin film transistor 100 of this embodiment is about 300 nm to about 600 nm, the typical thickness of the gate insulating film 30 is about 300 nm to about 500 nm, and the representative thickness of the channel 40 is. Typical thickness is about 20 nm to about 50 nm. In the thin film transistor 100 of this embodiment, the source electrode 52 and the drain electrode 54 have a typical thickness of about 300 nm to about 600 nm, and the insulating film 60 has a typical thickness of about 1 μm to 4 μm. A typical thickness of 70 is from about 50 nm to about 100 nm.

  In the present embodiment, the insulating film 60 is in direct contact with the channel 40 as shown in FIG. In addition, the redox potential of the second element 62 contained in the inorganic or organic material that is the base material of the insulating film 60 is lower than the redox potential of the first element contained in the channel 40.

  Therefore, in the thin film transistor 100 of the present embodiment, although the detailed mechanism is still unclear, for example, as shown in FIG. 2 in which the X region in FIG. 1 is enlarged, the interface region 42 with the insulating film 60 in the channel 40. 2, some elements in the insulating film 60 (typically part of the second element 62, but may contain oxygen or other impurities) and some elements in the channel 40 (typically the first element). Some bonding state (eg, ionic bond, covalent bond, coordinate bond, and / or hydrogen bond) with one element, which may contain oxygen or other impurities, may be formed. Further, as another example, as shown in FIG. 3 in which the X region in FIG. 1 is enlarged, in the interface region 42 with the insulating film 60 in the channel 40 and the interface region 64 with the channel 40 in the insulating film 60. , Some of the elements in the insulating film 60 (typically part of the second element 62 but may contain oxygen or other impurities) and some of the elements in the channel 40 (typically the first element). Some bonding state (eg, ionic bonds, covalent bonds, coordination bonds, and / or hydrogen bonds) may be formed with elements that are part of the element but may include oxygen or other impurities.

  Although not analyzed in detail at the present time, as described above, the interface state between the channel 40 and the insulating film 60 shown in FIG. 2 or FIG. Oxygen deficiency in the oxide semiconductor can be suppressed or prevented. As a result, fluctuations in electrical conductivity and the like in the channel 40 of the thin film transistor 100 including the oxide semiconductor are suppressed or prevented, so that various characteristics of the thin film transistor 100, particularly electrical characteristics and / or reliability can be improved. Can be realized. In FIGS. 2 and 3, the interface regions 42 and 64 are expressed with emphasis to make the drawings easy to see. For example, when forming the channel 40 and / or the insulating film 60 or depending on various conditions (heating temperature or cooling temperature, atmosphere, etc.) affecting the state of the interface regions 42 and 64 after the formation, the interface region 42, 64 may be a monoatomic layer to a thickness of 20 nanometers or less. Next, the insulating film 60 will be described in more detail.

[Insulating film 60 of this embodiment]
Examples of the inorganic material or organic material that is the base material of the insulating film 60 of the present embodiment are a siloxane compound, a polymer obtained by polymerizing a compound represented by the following formula (a), an acrylic resin, a polyimide resin, or a novolac resin. It is an insulating film containing at least one of organic materials represented by the above.
Below, the example of the polymer formed by condensing the compound shown by following formula (a) is demonstrated in detail.

<About the polymer formed by condensing the compound represented by the formula (a)>
The polymer formed by condensing the compound represented by the following formula (a) contains a siloxane compound or a metalloxane compound obtained by hydrolytic condensation of the compound represented by the formula (a). In addition, in this application, a "metalloxane compound" is a compound which has a metalloxane bond (MOM bond, M represents a metal atom). The following M corresponds to the second element in the present embodiment.

ＲａｘＭ（Ｒｂ）ｎ−ｘ （ａ）
（上記式（ａ）中、Ｍが示す元素は特に限定されないが、代表的には、Ｓｉ又はＭｎ，Ａｌ，Ｌａ，Ｔｉ，Ｚｒ，Ｓｎ、Ｓｉ、Ｈｆ，Ｍｇ，Ｃａ，Ｓｒ，Ｂａ，Ｋ，Ｒｂ，Ｌｉ，Ｎｄ，Ｓｍ，Ｈｆ，Ｔａ，Ｗ，Ｒｕ，Ｉｒ，Ｎｂ，Ｍｏ，Ｐｄ，及びＶの群から選択される1種又は２種以上の元素である。また、Ｒａは、炭素数１〜１５の有機基である。Ｒｂは、加水分解性基である。ｎは金属原子であるＭの価数であり、ｘは０〜（ｎ−１）の整数である。）

RaxM (Rb) nx (a)
(In the above formula (a), the element represented by M is not particularly limited, but is typically Si or Mn, Al, La, Ti, Zr, Sn, Si, Hf, Mg, Ca, Sr, Ba, K. , Rb, Li, Nd, Sm, Hf, Ta, W, Ru, Ir, Nb, Mo, Pd, and V are one or more elements, and Ra is carbon. An organic group having a number of 1 to 15. Rb is a hydrolyzable group, n is a valence of M which is a metal atom, and x is an integer of 0 to (n-1).

  As described above, it is a hydrolysis condensate of the compound of the above formula (a) having a hydrolyzable group (Rb). More specifically, the metalloxane compound is a hydrolysis condensate obtained by condensing some hydroxy groups of the hydrolyzed compound of the formula (a). Here, the compound having a hydrolyzable group is usually hydrolyzed by heating within a temperature range of room temperature (about 25 ° C.) to about 100 ° C. in the presence of non-catalyst and excess water. A compound having a group capable of generating a hydroxy group. In the composition for forming a conductive film of the present embodiment, the “siloxane compound or metalloxane compound” as the component (B) has some hydrolyzable groups in an unhydrolyzed state in the molecule. And those that remain uncondensed with other compounds.

  The siloxane compound or the metalloxane compound is a compound represented by the above formula (a) (hereinafter, appropriately referred to as compound (i)), or a compound represented by the following formula (b) (to be described later). And a hydrolysis condensate of compound (ii)). The hydrolysis reaction of the compound (i) represented by the above formula (a) and the compound (ii) represented by the following formula (b) is a partial hydrolysis group in the resulting hydrolysis condensate. May remain unhydrolyzed.

In the above formula (a), Ra is an organic group having 1 to 8 carbon atoms. Rb is a hydrolyzable group. n is a valence of M which is a metal atom, and x is an integer of 0 to (n-1).
In the above formula (a), examples of the organic group having 1 to 8 carbon atoms represented by Ra include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group, and an epoxy group. A group containing, a group containing a (meth) acryloyl group, a group containing a vinyl group, a group containing a mercapto group, and the like. Some or all of the hydrogen atoms of the aryl group, alkyl group, and cycloalkyl group may be substituted.

Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and a butyl group. Among these, an i-propyl group or a butyl group is preferable from the viewpoint of easy hydrolysis.
Examples of the cycloalkyl group having 3 to 8 carbon atoms are a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and an anthranyl group.
Examples of the group containing an epoxy group are 2- (3,4-epoxycyclohexyl) ethyl group, 3-glycidoxypropyl group, 3-oxetanylpropyl group and the like.
Examples of the group containing a (meth) acryloyl group include a 3-methacryloxypropyl group and a 3-acryloxypropyl group.
Examples of the group containing a vinyl group are a vinyl group and a p-styryl group.
An example of a group containing a mercapto group is a 3-mercaptopropyl group.

In the above formula (a), examples of the hydrolyzable group represented by Rb are an alkoxy group, an aryloxy group, a halogen atom, an acetoxy group, an isocyanate group, and the like. Among these, an alkoxy group is preferable, and a methoxy group, an ethoxy group, a propoxy group, or a butoxy group is more preferable.
In the above formula (a), preferred examples of the metal atom represented by M are titanium (Ti), zirconium (Zr), tin (Sn), silicon (Si), or aluminum (Al). Note that by selecting the above-described titanium, silicon, or the like as the metal atom, the substrate adhesion with the semiconductor layer of the formed insulating film can be improved.

Examples of the compound (i) represented by the above formula (a) are tetra-i-propoxy titanium, tetra-n-butoxy titanium, tetraethoxy titanium, tetramethoxy titanium, tetra-i-propoxy zirconium, tetra-n- Metal compounds substituted with four hydrolyzable groups such as butoxyzirconium, tetraethoxyzirconium, tetramethoxyzirconium;
Methyl trimethoxy titanium, methyl triethoxy titanium, methyl tri-i-propoxy titanium, methyl tributoxy zirconium, ethyl trimethoxy zirconium, ethyl triethoxy zirconium, ethyl tri-i-propoxy zirconium, ethyl tributoxy zirconium, butyl trimethoxy titanium, phenyl Trimethoxytitanium, naphthyltrimethoxytitanium, phenyltriethoxytitanium, naphthyltriethoxytitanium, aminopropyltrimethoxytitanium, aminopropyltriethoxyzirconium, 2- (3,4-epoxycyclohexyl) ethyltrimethoxyzirconium, γ-glycid Xypropyltrimethoxyzirconium, 3-isocyanopropyltrimethoxyzirconium, 3-isocyanopropyltriethoxy A metal compound substituted with one non-hydrolyzable group such as zirconium and three hydrolyzable groups; or two non-hydrolyzable groups such as dimethyldimethoxytitanium, diphenyldimethoxytitanium, dibutyldimethoxyzirconium Metal compounds substituted with two hydrolyzable groups;
Three non-hydrolyzable groups such as trimethylmethoxy titanium, triphenylmethoxy titanium, tributylmethoxy titanium, tri (3-methacryloxypropyl) methoxyzirconium, tri (3-acryloxypropyl) methoxyzirconium and one hydrolysis A metal compound substituted with a functional group.

  Among these, a preferred example of the compound (i) represented by the above formula (a) is a metal compound substituted with four hydrolyzable groups, and a more preferred example is tetra-i-propoxy. Titanium or tetra-n-butoxy titanium.

  In the synthesis of the metalloxane compound of the composition for forming the insulating film 60 of this embodiment, a suitable example of the amount of the compound (i) used in the above formula (a) is based on the total hydrolyzable metal compound used. Compound (i) is 50 mol% to 100 mol%, and a more preferred example is 80 mol% to 100 mol%. The lower limit of the compound (i) is not particularly limited. However, when the numerical value is less than 50 mol%, the metalloxane compound having the desired characteristics as the insulating film 60 of this embodiment may not be obtained.

  As above-mentioned, another suitable example of the metalloxane compound of this embodiment is a hydrolysis-condensation product of the compound (ii) represented by the following formula (b).

  In said formula (b), X shows the metal atom selected from the group of Ti, Zr, Sn, Si, and Al. Rc and Rd are organic groups having 1 to 8 carbon atoms. Re is a ligand. m is a valence of X which is a metal atom, p is an integer of 0 to (m−2), and q is an integer of 1 to (m−1).

  Examples of the organic group having 1 to 8 carbon atoms represented by Rc and Rd in the above formula (b) are the groups exemplified as the organic group having 1 to 8 carbon atoms represented by Ra in the above formula (a). Is the same group.

  In the above formula (b), examples of the ligand represented by Re are diketonate anions such as acetylacetonate anion, carboxylate anions, ammonia, amines, ketones, alcohols, carbon monoxide, and the like.

Examples of the compound (ii) represented by the above formula (b) are triethoxymono (acetylacetonato) titanium, tri-n-propoxymono (acetylacetonato) titanium, tri-i-propoxymono (acetylacetonate). ) Titanium compounds such as titanium, di-i-propoxybis (acetylacetonato) titanium, di-n-butoxybis (acetylacetonato) titanium; or triethoxymono (acetylacetonato) zirconium, tri-n-propoxymono ( Zirconium compounds such as acetylacetonato) zirconium, tri-i-propoxymono (acetylacetonato) zirconium, di-i-propoxybis (acetylacetonato) zirconium, di-n-butoxybis (acetylacetonato) zirconium, and the like. .

  A suitable example of the amount of the above-mentioned compound (ii) used for the synthesis of the metalloxane compound is 50 mol% to 100 mol% with respect to the total hydrolyzable metal compound used, and a more suitable example is 80 It is mol%-100 mol%. The lower limit value of the compound (ii) is not particularly limited. However, when the numerical value is less than 50 mol%, the metalloxane compound having the desired characteristics as the insulating film 60 of the present embodiment may not be obtained.

  In addition, as long as it hydrolyzes at least one part of a compound (i) and a compound (ii), converts a hydrolysable group into a hydroxyl group, and causes a condensation reaction, the compound (i) and compound mentioned above The conditions for hydrolyzing and condensing (ii) are not particularly limited. However, if one specific example is shown, it is the following example.

  The suitable example of the water used for the hydrolysis condensation reaction of the compound (i) and the compound (ii) described above is water purified by a method such as reverse osmosis membrane treatment, ion exchange treatment, or distillation. By using such purified water, side reactions can be suppressed and the reactivity of hydrolysis can be improved. A suitable example of the amount of water used is 0.1 mol to 3 mol with respect to 1 mol of the total amount of hydrolyzable groups possessed by the compound (i) and the compound (ii). 0.3 mol to 2 mol, and a more preferable example is 0.5 mol to 1.5 mol. By using such an amount of water, the reaction rate of the hydrolysis condensation can be optimized.

  The solvent that can be used for the hydrolysis condensation described above is not particularly limited. Specific examples of the solvent include ethylene glycol monoalkyl ether acetate, diethylene glycol dialkyl ether, propylene glycol monoalkyl ether, propylene glycol monoalkyl ether acetate, or propionic acid esters. Among these solvents, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether acetate or methyl 3-methoxypropionate is more preferable.

  The hydrolysis condensation reaction described above is preferably an acid catalyst (for example, hydrochloric acid, sulfuric acid, nitric acid, formic acid, oxalic acid, acetic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, phosphoric acid, acidic ion exchange resin, various Lewis acids). A basic catalyst (for example, ammonia, primary amines, secondary amines, tertiary amines, nitrogen-containing compounds such as pyridine; basic ion exchange resins; hydroxides such as sodium hydroxide; carbonates such as potassium carbonate) Salt; carboxylates such as sodium acetate; various Lewis bases] or alkoxides (for example, zirconium alkoxides, titanium alkoxides, aluminum alkoxides) and the like. An example of an aluminum alkoxide is tri-i-propoxyaluminum. A suitable example of the amount of the catalyst used is 0.2 mol or less with respect to 1 mol of the monomer of the hydrolyzable compound from the viewpoint of promoting the hydrolysis condensation reaction. Moreover, a more suitable example is 0.00001 mol-0.1 mol with respect to 1 mol of the above-mentioned monomers.

  The reaction temperature and reaction time in the hydrolysis condensation described above are appropriately set. For example, the following conditions can be employed. A suitable example of reaction temperature is 0 degreeC-200 degreeC, and a more suitable example is 20 degreeC-150 degreeC. A preferred example of the reaction time is 10 minutes to 24 hours, and a more preferred example is 30 minutes to 12 hours. By setting such reaction temperature and reaction time, the hydrolysis condensation reaction can be performed most efficiently. In this hydrolysis condensation, a compound having hydrolyzability, water, and a catalyst may be added at a time in the reaction system to carry out the reaction in one step, or a compound having hydrolyzability, water, and The hydrolysis and condensation reaction may be performed in multiple stages by adding the catalyst in the reaction system in two or more steps.

  As a method for measuring the molecular weight of the condensate of the metalloxane compound of the present embodiment, a method of measuring as a weight average molecular weight (Mw) in terms of polystyrene using GPC (gel permeation chromatography) using tetrahydrofuran as a mobile phase is adopted. be able to. The Mw of the condensate is preferably set to a value within the range of 500 to 10,000, and more preferably set to a value within the range of 1000 to 5000. Further, the molecular weight distribution (Mw / Mn) is preferably 3.0 or less, and more preferably 2.6 or less. By setting Mw / Mn of the condensate to 3.0 or less, it is possible to form the insulating film 60 of the present embodiment that has excellent adhesion to the semiconductor layer.

<About other polymers>
In the present embodiment, in addition to the condensate of the compound represented by the formula (a) shown above, a polymer compound obtained by polymerizing an organic compound can also be used. Typical examples are a polymer compound obtained by polymerizing a compound having an unsaturated double bond with a radical polymerization initiator, a phenol resin obtained by condensing phenol with formaldehyde in the presence of a catalyst, a dicarboxylic acid component and a diamine component. Is a polyamic acid obtained by dehydration condensation or polyimide. Such a polymer is preferably an alkali-soluble resin having alkali solubility that can exhibit solubility in an alkali developer or the like. This will be described in detail below.

  Suitable examples of the polymer contained in the insulating film 60 of the present embodiment are an acrylic polymer having a carboxyl group, a polyimide polymer, a novolac polymer, and the like. Next, each of the acrylic polymer having a carboxyl group, the polyimide polymer, and the novolac polymer will be described in more detail.

(Polymer having a carboxyl group)
The suitable example of the polymer which has a carboxyl group in this embodiment contains the structural unit which has a carboxyl group, and the structural unit which has a polymeric group. In this case, the polymer having a carboxyl group is not particularly limited as long as it includes a structural unit having a carboxyl group and a structural unit having a polymerizable group and has alkali developability (alkali solubility).

  The structural unit having a polymerizable group is preferably at least one structural unit selected from the group of structural units having an epoxy group and structural units having a (meth) acryloyloxy group.

  Suitable examples of the method for forming the structural unit having a (meth) acryloyloxy group include a method of reacting an epoxy group in a copolymer with (meth) acrylic acid, and a carboxyl group in the copolymer having an epoxy group. A method of reacting a (meth) acrylic acid ester, a method of reacting a hydroxyl group in a copolymer with a (meth) acrylic acid ester having an isocyanate group, or a hydroxyl (meth) acrylate at an acid anhydride site in the copolymer For example, a method of reacting an ester. Among these, a method of reacting a (meth) acrylic acid ester having an epoxy group with a carboxyl group in the copolymer is particularly preferable.

  The polymer containing a structural unit having a carboxyl group and a structural unit having an epoxy group as a polymerizable group is (A1) at least one selected from the group consisting of an unsaturated carboxylic acid and an unsaturated carboxylic anhydride (hereinafter referred to as It can be synthesized by copolymerizing “(A1) compound”) and (A2) an epoxy group-containing unsaturated compound (hereinafter also referred to as “(A2) compound”). In this case, the acrylic polymer having a carboxyl group is formed from a structural unit formed from at least one selected from the group of unsaturated carboxylic acids and unsaturated carboxylic anhydrides, and an epoxy group-containing unsaturated compound. It becomes a copolymer containing a structural unit.

  The polymer having a carboxyl group is obtained by, for example, copolymerizing a compound (A1) giving a carboxyl group-containing structural unit and a compound (A2) giving an epoxy group-containing structural unit in the presence of a polymerization initiator in a solvent. Can be manufactured by. Further, the polymer having the carboxyl group is made into a copolymer by further adding (A3) a hydroxyl group-containing unsaturated compound (hereinafter also referred to as “(A3) compound”) that gives a hydroxyl group-containing structural unit. You can also. Further, in the production of the acrylic polymer having a carboxyl group, the (A4) compound (the (A1) compound, the (A2) compound and the (A4) compound) and the (A2) compound and the (A3) compound, A3) An unsaturated compound providing a structural unit other than the structural unit derived from the compound) may be further added to form a copolymer. Next, each compound of (A1) to (A3) will be described in detail.

(A1) Compound (A1) Examples of the compound include unsaturated monocarboxylic acid, unsaturated dicarboxylic acid, unsaturated dicarboxylic acid anhydride, or poly [carboxylic acid] mono [(meth) acryloyloxyalkyl] ester. is there.
Examples of unsaturated monocarboxylic acids are acrylic acid, methacrylic acid, or crotonic acid. Examples of unsaturated dicarboxylic acids are maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, and the like. Examples of the unsaturated dicarboxylic acid anhydride include the anhydrides of the compounds exemplified as the dicarboxylic acid. Of these (A1) compounds, acrylic acid, methacrylic acid, and maleic anhydride are preferred. Acrylic acid, methacrylic acid, and maleic anhydride are more preferable from the viewpoint of copolymerization reactivity, solubility in an aqueous alkali solution, and availability. These (A1) compounds may be used alone or in combination of two or more.

  A suitable example of the use ratio of the compound (A1) is based on the sum of the compound (A1) and the compound (A2) (however, any (A3) compound and (A4) compound can be included if necessary). It is 5 mass%-30 mass%, and a more suitable example is 10 mass%-25 mass%. (A1) By adjusting the use ratio of the compound to 5% by mass to 30% by mass, it is possible to optimize the solubility of the acrylic polymer having a carboxyl group in an alkaline aqueous solution and to form a film having excellent radiation sensitivity. it can.

(A2) Compound (A2) An example of the compound (A2) is an epoxy group-containing unsaturated compound having radical polymerizability. Examples of the epoxy group are an oxiranyl group (1,2-epoxy structure) or an oxetanyl group (1,3-epoxy structure). Examples of unsaturated compounds having an oxiranyl group include glycidyl acrylate, glycidyl methacrylate, 2-methylglycidyl methacrylate, 3,4-epoxybutyl acrylate, 3,4-epoxybutyl methacrylate, 6, 7-epoxyheptyl, methacrylic acid 6,7-epoxyheptyl, α-ethylacrylic acid-6,7-epoxyheptyl, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, or methacryl Acid 3,4-epoxycyclohexylmethyl and the like. Among these, glycidyl methacrylate, 2-methylglycidyl methacrylate, -6,7-epoxyheptyl methacrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, 3, methacrylate 4-Epoxycyclohexyl, 3,4-epoxycyclohexyl acrylate, or the like is preferable from the viewpoints of copolymerization reactivity and solvent resistance of the cured film to be obtained. Examples of unsaturated compounds having an oxetanyl group include 3- (acryloyloxymethyl) oxetane, 3- (acryloyloxymethyl) -2-methyloxetane, 3- (acryloyloxymethyl) -3-ethyloxetane, 3- (Acryloyloxymethyl) -2-phenyloxetane, 3- (2-acryloyloxyethyl) oxetane, 3- (2-acryloyloxyethyl) -2-ethyloxetane, 3- (2-acryloyloxyethyl) -3-ethyl Acrylic acid esters such as oxetane, 3- (2-acryloyloxyethyl) -2-phenyloxetane; or 3- (methacryloyloxymethyl) oxetane, 3- (methacryloyloxymethyl) -2-methyloxetane, 3- (methacryloyloxy) Methyl) -3-eth Luoxetane, 3- (methacryloyloxymethyl) -2-phenyloxetane, 3- (2-methacryloyloxyethyl) oxetane, 3- (2-methacryloyloxyethyl) -2-ethyloxetane, 3- (2-methacryloyloxyethyl) Methacrylic acid esters such as -3-ethyloxetane, 3- (2-methacryloyloxyethyl) -2-phenyloxetane, and 3- (2-methacryloyloxyethyl) -2,2-difluorooxetane.

  Preferable examples of these (A2) compounds are glycidyl methacrylate, 3,4-epoxycyclohexyl methacrylate, and 3- (methacryloyloxymethyl) -3-ethyloxetane. These (A2) compounds may be used alone or in combination of two or more.

  A suitable example of the use ratio of the compound (A2) is based on the sum of the compound (A1) and the compound (A2) (however, it can include any compound (A3) and compound (A4) as necessary) It is 5 mass%-60 mass%, and a more suitable example is 10 mass%-50 mass%. (A2) By making the usage-amount of a compound into 5 mass%-60 mass%, the cured film which has the outstanding sclerosis | hardenability etc. can be formed, and the pattern which consists of a polymer can be formed on a board | substrate. .

(A3) Compound The example of the (A3) compound is not particularly limited as long as it is an unsaturated compound other than the above (A1) compound and (A2) compound. Examples of the compound (A3) include a (meth) acrylic acid ester having a hydroxyl group, a (meth) acrylic acid ester having a phenolic hydroxyl group, or hydroxystyrene. Other examples of the compound (A3) include methacrylic acid chain alkyl ester, methacrylic acid cyclic alkyl ester, acrylic acid chain alkyl ester, acrylic acid cyclic alkyl ester, methacrylic acid aryl ester, acrylic acid aryl ester, unsaturated Examples thereof include dicarboxylic acid diesters, maleimide compounds, unsaturated aromatic compounds, conjugated dienes, unsaturated compounds having a tetrahydrofuran skeleton, and other unsaturated compounds.

  (A3) The suitable example of the usage-amount of a compound is 10 mass%-80 mass% based on the sum total of (A1) compound, (A2) compound, and (A3) compound.

  The above-mentioned polymer can be synthesized with reference to the descriptions in Japanese Patent No. 2961722, Japanese Patent No. 3241399, Japanese Patent No. 4766268, and Japanese Patent No. 4544370.

(Polyimide polymer)
The example of the polyimide polymer in this embodiment is a polyimide polymer obtained by condensing an acid component and an amine component. In addition, the suitable example of a polyimide polymer is selecting tetracarboxylic dianhydride as an acid component, and selecting diamine as an amine component.

  A suitable example of the tetracarboxylic dianhydride used for forming the polyimide polymer is an organic group having 5 to 40 carbon atoms containing an aromatic ring or a cyclic aliphatic group.

  Suitable examples of the tetracarboxylic dianhydride used for forming the polyimide polymer include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetra. Carboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3 '-Benzophenonetetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 1, 1-bis (3,4-dicarboxyphenyl) ethane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride , Screw (2, -Dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 2,2-bis (3,4- Dicarboxyphenyl) hexafluoropropane dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, 9,9-bis (3,4-dicarboxyphenyl) fluorene dianhydride, or 9,9-bis {4- (3,4-dicarboxyphenoxy) phenyl} fluorene dianhydride.

  Suitable examples of the diamine used for forming the polyimide polymer include 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenylmethane, 3,4 '-Diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfide, 3,4′-diaminodiphenylsulfide, 4,4′-diaminodiphenylsulfide, m-phenylenediamine, p-phenylenediamine, 1,4-bis (4-aminophenoxy) benzene, 9,9-bis (4 -Aminophenyl) fluorene and / or indicated below It is an elephant diamine. In addition, you may use 2 or 3 types or more of each above-mentioned example.

  Other acid components and amine components are synthesized using the compounds described in Japanese Patent No. 4548001, Japanese Patent No. 4911248, Japanese Patent No. 498927, Japanese Patent Application Laid-Open No. 2011-133699, and Japanese Patent Application Laid-Open No. 2012-232314. be able to.

  In this embodiment, an example of a method for synthesizing a polyimide polymer is a method in which a polyimide precursor is obtained using a known method and then imidized using a known imidization reaction method. In addition, as an example of a known synthesis method of a polyimide precursor, the polyimide precursor is obtained by replacing a part of the diamine with a monoamine that is a terminal blocking agent, or a part of the acid dianhydride. It is obtained by reacting an amine component and an acid component in place of the monocarboxylic acid, acid anhydride, monoacid chloride compound or monoactive ester compound. For example, a method of reacting tetracarboxylic dianhydride and diamine (partially substituted with monoamine) at low temperature, tetracarboxylic dianhydride (partially acid anhydride, monoacid chloride compound or monoactivity at low temperature) A method in which an ester compound is substituted) and a diamine, a method in which a diester is obtained by tetracarboxylic dianhydride and an alcohol, and then a reaction is performed in the presence of a diamine (partially substituted with a monoamine) and a condensing agent, or tetra After obtaining a diester with carboxylic dianhydride and alcohol, a method of converting the remaining dicarboxylic acid to acid chloride and reacting with diamine (partially substituted with monoamine) can be employed.

(Novolac polymer)
A novolak polymer, which is one of the preferred examples of the polymer used in the insulating film 60 of the present embodiment, can be obtained by polycondensing phenols with aldehydes such as formalin by a known method.

  Examples of phenols for obtaining a novolak polymer which is one of the preferred examples in the insulating film 60 of the present embodiment are phenol, p-cresol, m-cresol, o-cresol, 2,3-dimethylphenol, 2, 4-dimethylphenol, 2,5-dimethylphenol, 2,6-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,3,4-trimethylphenol, 2,3,5-trimethylphenol 3,4,5-trimethylphenol, 2,4,5-trimethylphenol, methylene bisphenol, methylene bis p-cresol, resorcin, catechol, 2-methyl resorcin, 4-methyl resorcin, o-chlorophenol, m-chlorophenol , P-chlorophenol, 2,3-dichloropheno M-methoxyphenol, p-methoxyphenol, p-butoxyphenol, o-ethylphenol, m-ethylphenol, p-ethylphenol, 2,3-diethylphenol, 2,5-diethylphenol, p-isopropylphenol, α-naphthol, β-naphthol and the like. In addition, you may use 2 or 3 types or more of each above-mentioned example.

  Further, in the insulating film 60 of the present embodiment, examples of aldehydes for obtaining a novolak polymer which is one of suitable examples are paraformaldehyde, acetaldehyde, benzaldehyde, hydroxybenzaldehyde, chloroacetaldehyde, and the like in addition to formalin. . In addition, you may use 2 or 3 types or more of each above-mentioned example.

  The insulating film 60 of this embodiment includes at least one of a polymer obtained by condensing the compound represented by the above formula (a) or a polymer obtained by condensing the compound represented by the above formula (a). It can also be formed by applying and baking the composition on a substrate. An example of such a composition is a thermosetting composition that cures the film only by heating after coating. Another example is a curable composition (also referred to as “curable composition” in the present application) in which an insulating film is formed by performing post-application exposure and development, followed by heating. As such a radiation sensitive composition, either positive or negative radiation sensitive composition can be used as required.

  As a polymerization initiator or a solvent other than a polymer or a polymer obtained by condensing the compound represented by the above formula (a) contained in the thermosetting composition or radiation sensitive composition as described above A known compound can be applied. Examples of the polymerization initiator or the solvent include JP 2010-84126 A, WO 2008/123388, JP 2013-219173 A, JP 2010-8603 A, and JP 2009-223293 A. Or a compound described in JP 2010-27033 A or the like.

  In the insulating film 60 of the present embodiment, when a polymer is used, a compound represented by the formula (a) or a condensate obtained by condensing the compound represented by the formula (a) can be included. By including such a compound or condensate, the insulating film 60 can exhibit an effect in suppressing or preventing oxygen vacancies in the oxide semiconductor. In addition, in the composition containing a polymer, a preferable example of the amount of the compound or the condensate used is in a range from 0.1 parts by mass to 100 parts by mass with respect to 100 parts by mass of the polymer. A suitable example is a range from 1 part by weight to 50 parts by weight. By including the compound or the condensate in such a range, the insulating film 60 can contribute to the suppression or prevention of oxygen vacancies in the oxide semiconductor, and the manufacturing process can be simplified. In addition, a production method excellent in mass productivity can be provided.

  Moreover, the example of the 1st element of this embodiment is not specifically limited. Examples of typical first elements are In, Ga, Zn, Zr, Mn, Al, La, Ti, Hf, Si, Mg, Ca, Sr, Ba, K, Rb, Li, Nd, Sm, Hf, It is one or more selected from the group consisting of Ta, W, Ru, Ir, Nb, Mo, Pd, and V. Note that typical examples of the first element are indium (In), gallium (Ga), and zinc (Zn). Therefore, a typical example of an oxide semiconductor employed as the channel 40 in the thin film transistor 100 of this embodiment is a first element oxide semiconductor. Note that the oxide semiconductor is not limited to an amorphous state. For example, the oxide semiconductor can include a microcrystal. The type of the second element of the present embodiment is not particularly limited as long as the redox potential of the second element is lower than the redox potential of the first element. The most typical example of the second element is zirconium (Zr). Examples of typical second elements are Zr, Mn, Al, La, Ti, Hf, Si, Mg, Ca, Sr, Ba, K, Rb, Li, Nd, Sm, Hf, Ta, W, Ru, Ir, Nb, Mo, Pd, or V.

  Incidentally, in the present application, the first element is not necessarily limited to one metal element, and may include a plurality of metal elements. Further, the second element 62 is not necessarily limited to one metal element, and may include a plurality of metal elements. From the viewpoint of accurately suppressing or preventing oxygen vacancies in the oxide semiconductor containing the first element, when the first element contains a plurality of metal elements and the second element 62 contains a plurality of metal elements, It is preferable that at least one metal element of the two elements 62 has a lower redox potential than a metal element having the lowest redox potential among the plurality of metal elements as the first element. In addition, when the first element includes a plurality of metal elements and the second element 62 includes a plurality of metal elements, the metal element having the highest redox potential among the plurality of metal elements as the second element 62 More preferably, the redox potential of the metal element is lower than the redox potential of the metal element having the lowest redox potential among the plurality of metal elements as the first element. In addition, as described above, the ordinal numbers of the “first element” and the “second element” are merely representations for convenience used to distinguish each other. Therefore, there is no superiority or inferiority between the “first element” and the “second element”.

  From the viewpoint of accurately suppressing or preventing oxygen vacancies in the oxide semiconductor containing the first element, when the first element contains a plurality of metal elements and the second element 62 contains a plurality of metal elements, It is preferable that at least one metal element of the two elements 62 has a lower redox potential than a metal element having the lowest redox potential among the plurality of metal elements as the first element. In addition, when the first element includes a plurality of metal elements and the second element 62 includes a plurality of metal elements, the metal having the highest redox potential among the plurality of metal elements as the second element 62 More preferably, the redox potential of the element is lower than the redox potential of the metal element having the lowest redox potential among the plurality of metal elements as the first element.

In addition, it is a preferable aspect of the present embodiment that the above-described insulating film 60 further has a property of blocking light in the ultraviolet region (typically, a wavelength of less than 350 nm), that is, an ultraviolet light shielding property. By irradiating the channel 40 with ultraviolet light having high energy, conduction electrons may increase due to electrons being emitted from the metal elements in the channel 40 or in the interface region with each layer in contact with the channel 40. . When the channel 40 is irradiated with ultraviolet rays, if water molecules are adsorbed on the surface (including the back surface) of the channel 40, oxygen ions (O ⁻ or O ²⁻ ) are detached from the channel 40. The possibility to do increases. As a result, an increase in free electrons in the interface region with each layer in or in contact with the channel 40 may occur. As a result of the above-described phenomena, there is a high possibility that a change in electrical characteristics (for example, a change in threshold voltage of a transistor) occurs. Therefore, the presence of the insulating film 60 having ultraviolet light shielding properties for suppressing or preventing the above-described phenomena can contribute to stabilization of electrical characteristics and improvement of reliability of the thin film transistor 100 of the present embodiment. From the viewpoint of blocking water molecules, the insulating film 60 described above further includes a gas barrier property (particularly, a barrier property against water vapor), which is another preferable aspect of the present embodiment.

  In addition, it is another preferable aspect of the present embodiment that the above-described insulating film 60 has photosensitivity (for example, photosensitivity to light in the ultraviolet region). Since the insulating film 60 has photosensitivity, patterning can be performed by a lithography method when the insulating film 60 is formed, and a processing step of the insulating film 60 in a later process can be omitted.

  Note that an example for the insulating film 60 to obtain the above-described ultraviolet light shielding property is to add an ultraviolet absorber, a phenolic compound, an organic or inorganic pigment to the insulating film 60. In addition, an example for the insulating film 60 to obtain the above-described gas barrier property is to add a crosslinking agent such as an organic or inorganic filler or a polyfunctional epoxy to the insulating film 60. In addition, as an example for obtaining the photosensitivity of the insulating film 60, a photosensitive composition portion can be formed by adding quinonediazide, a photopolymerization initiator, or the like to the insulating film forming composition.

[Thin Film Transistor Manufacturing Method]
(1) Formation of Gate Electrode 20 and Formation of Gate Insulating Film 30 In this embodiment, first, the shape of the gate electrode 20 is formed on the substrate 10 by a known film forming method (such as a CVD method) and a photolithography method. To be processed. Thereafter, the gate insulating film 30 is formed on the substrate 10 and the gate electrode 20 by a known film forming method (CVD method or coating method) and, if necessary, a photolithography method.

(2) Formation of channel 40 and formation of source electrode 52 and drain electrode 54 Subsequently, processing is performed by sputtering and photolithography so that the shape of channel 40 is mainly composed of an oxide semiconductor containing the first element. Is done. More specifically, an oxide semiconductor layer containing the first element is formed by sputtering, a resist pattern is formed on the upper layer of the oxide semiconductor layer by photolithography, and then the oxide is formed by wet etching or dry etching. The semiconductor layer is processed into the shape of the channel 40. Thereafter, the resist pattern is removed. Thereafter, the film is processed into a shape of the channel 40 and each shape of the source electrode 52 and the drain electrode 54 by a known film formation method (sputtering method or CVD method) and a photolithography method. The intermediate structure shown is formed.

(3) Formation of Insulating Film 60 and Formation of Lead Electrode 70 Thereafter, an insulating base material (for example, polysiloxane compound or polymetallo) is formed on the gate electrode 20, the source electrode 52, the drain electrode 54, and the channel 40. An insulating film containing the second element 62 is formed in the (xane compound).

  Specifically, an insulating film can be formed by forming a precursor film of a base material precursor on a substrate by spin coating, and drying, firing and curing. An example of drying, baking and curing is to perform the film of the precursor on a hot plate heated to 50 ° C. to 135 ° C. for 60 seconds to 180 seconds. In addition, it is a more preferable aspect to perform the film | membrane of this precursor for 80 second-135 second on the hotplate heated at 65 degreeC-130 degreeC.

  Thereafter, the insulating film 60 shown in FIG. 5 is processed by photolithography and etching. Note that photolithography and etching may be performed continuously from drying, baking, and curing. For example, those steps may be performed after leaving for 2 to 10 minutes (in other words, PED: Post Exposure Delay). Further, in the photolithography method, when the film plate curing after light irradiation is insufficient, before the development step, 1 minute at 60 ° C. to 80 ° C., preferably 30 seconds to 2 minutes at 50 ° C. to 100 ° C., More preferably, baking and curing (in other words, PEB: Post Exposure Bake) may be performed on a hot plate at 55 to 85 ° C. for 1 to 1.5 minutes.

  Then, the insulating film 60 is formed by performing main baking. A specific example of the main baking is baking and curing at 150 ° C. to 380 ° C. for 20 minutes to 120 minutes. Note that, when the insulating film 60 is baked and cured, a two-step baking process is preferably performed in order to ensure adhesion to the substrate and uniformity of the formed film.

  More specifically, for example, after performing the first stage firing for 10 minutes to 60 minutes at 250 ° C. or lower, the firing step for 10 minutes to 60 minutes while continuously raising the temperature to 280 ° C. or higher. Is done. That is, a baking process at 250 ° C. or lower and a baking process at 280 ° C. or higher are performed. In a more preferred example, after performing the first stage baking at 180 ° C. or lower for 10 minutes to 60 minutes, the temperature is continuously raised to 300 ° C. or higher, and baking is performed for 10 minutes to 60 minutes. Is done. That is, a baking step of 180 ° C. or lower and a baking step of 300 ° C. or higher are performed. Note that the above-described baking step may include a step of periodically or irregularly reducing the temperature for heating the insulating film 60 between the baking step of 180 ° C. or lower and the baking step of 300 ° C. or higher. .

  By performing the two-stage baking process as described above, it is possible to suppress the occurrence of cracks in the insulating film due to, for example, a rapid curing reaction. Furthermore, after that, it is processed into a shape of the extraction electrode 70 by a known film formation method (sputtering method or the like) and, if necessary, a photolithography method. As a result, as shown in FIG. 6, the thin film transistor 100 can be manufactured. Note that each of the above-described materials can be used as appropriate as the inorganic material or the organic material which is a base material of the insulating film 60.

  As described above, the thin film transistor 100 of this embodiment includes the channel 40 whose main component is an oxide semiconductor containing the first element. In addition, an insulating film 60 containing a second element 62 having a redox potential lower than the redox potential of the first element in the insulating base material is in contact with the channel 40. Therefore, at least in the interface region between the channel 40 (mainly the oxide semiconductor) and the insulating film 60, the second element 62 having a low redox potential, that is, the presence of the second element 62 that is difficult to reduce compared to the first element, Typically, the possibility that an oxygen atom or an oxygen ion in the oxide semiconductor and the second element 62 form some bonding state is increased. Then, oxygen vacancies in the oxide semiconductor are suppressed or prevented, and thus various characteristics of the thin film transistor 100 including the oxide semiconductor, in particular, electrical characteristics and / or reliability can be improved.

<Second Embodiment>
FIG. 7 is a schematic cross-sectional view of the thin film transistor 200 in the present embodiment. In the thin film transistor 200 of this embodiment, the gate insulating film 30 of the first embodiment is changed to a gate insulating film 230 in which the second element 232 is contained in an inorganic material or an organic material that is an insulating base material. Except for the point and the point that the insulating film 60 of the first embodiment is changed to the insulating film 260 not containing the second element, and the point that the passivation film 80 made of silicon oxide or silicon nitride is disposed, This is the same as the thin film transistor 100 of the embodiment. Therefore, the description which overlaps with 1st Embodiment may be abbreviate | omitted.

  As shown in FIG. 7, the gate insulating film 230 containing the second element 232 is in direct contact with the lower side of the channel 40 whose main component is an oxide semiconductor containing the first element. In addition, the redox potential of the second element 232 contained in the gate insulating film 230 is lower than the redox potential of the first element contained in the channel 40. An example of the base material of the gate insulating film 230 is an insulating film in which the second element 232 is included in the polymetalloxane compound. In addition, similarly to the insulating film 60 of the first embodiment, the gate insulating film 230 (the same as the gate insulating film 230 used in other embodiments) is insulated from the inorganic material or organic material that is the base material. Each material that can be used as the film 60 can be used as appropriate.

  Therefore, in the thin film transistor 200 of this embodiment, in the interface region between the channel 40 and the gate insulating film 230, a part of the second element 232 and a part of the channel 40 (typically the first element). Any bond state (eg, ionic bond, covalent bond, coordination bond, and / or hydrogen bond) may be formed.

  Note that the gate insulating film 230 in this embodiment can be formed by the following film formation method. Specifically, an insulating film can be formed by forming a precursor film of a base material precursor on a substrate by spin coating, and drying, firing and curing. Thereafter, the insulating film 230 can be formed by performing pattern formation and etching by a photolithography method.

  In the thin film transistor 200 of this embodiment, a passivation film 80 is formed on a part of the gate insulating film 230, the channel 40, the source electrode 52, and the drain electrode 54. An example of the material constituting the passivation film 80 is silicon oxide or silicon nitride. The passivation film 80 of this embodiment suppresses or prevents the channel 40 from coming into contact with water molecules mainly by exhibiting gas barrier properties. An insulating film 260 is formed on the passivation film 80. Examples of the material forming the insulating film 260 are acrylic resin, polyimide resin, and / or siloxane resin. Further, the extraction electrode 70 is formed on the insulating film 260 in the same manner as in the method of the first embodiment.

  As described above, the thin film transistor 200 of this embodiment includes the channel 40 whose main component is an oxide semiconductor containing the first element. In addition, the gate insulating film 230 containing the second element 232 having a redox potential lower than the redox potential of the first element in the insulating base material is in contact with the channel 40. Therefore, at least in an interface region between the channel 40 (mainly an oxide semiconductor) and the gate insulating film 230, typically, an oxygen atom or an oxygen ion in the oxide semiconductor is present due to the presence of the second element 232 having a low redox potential. And the second element 232 are more likely to form some bonding state. Then, oxygen vacancies in the oxide semiconductor are suppressed or prevented, and thus various characteristics of the thin film transistor 200 including the oxide semiconductor, in particular, electrical characteristics and / or reliability can be improved.

  Incidentally, it is another preferable embodiment that the above-described gate insulating film 230 has a property of blocking light in an ultraviolet region (typically, a wavelength of less than 350 nm), that is, an ultraviolet light shielding property. In addition, the gate insulating film 230 has a gas barrier property (particularly, a barrier property against water vapor), which is another preferable aspect of the present embodiment. In addition, it is another preferable aspect of the present embodiment that the gate insulating film 230 described above has photosensitivity (for example, photosensitivity to light in the ultraviolet region).

<Third Embodiment>
FIG. 8 is a schematic cross-sectional view of the thin film transistor 300 in the present embodiment. In the thin film transistor 300 of the present embodiment, the etch stop insulating film 90 of the present embodiment is disposed on the channel 40, and the gate insulating film 30 of the first embodiment is disposed instead of the gate insulating film 230. Except for this point, it is the same as the thin film transistor 200 of the second embodiment. Therefore, the description which overlaps with 1st Embodiment or 2nd Embodiment may be abbreviate | omitted.

  The etch stop insulating film 90 of this embodiment includes a second element 92 in an inorganic material or an organic material which is a base material having an insulating property. As shown in FIG. 8, the etch stop insulating film 90 containing the second element 92 is in direct contact with the upper side of the channel 40 whose main component is an oxide semiconductor containing the first element. In addition, the redox potential of the second element 92 contained in the etch stop insulating film 90 is lower than the redox potential of the first element contained in the channel 40. An example of the base material of the etch stop insulating film 90 is an insulating film in which the second element 92 is included in the polymetalloxane compound. In addition, the etch stop insulating film 90 (same as the etch stop insulating film 90 used in the other embodiments) is also the same as the insulating film 60 of the first embodiment. Each material that can be used as the insulating film 60 can be used as appropriate.

  Therefore, in the thin film transistor 300 of this embodiment, a part of the second element 92 and a part of the channel 40 (typically, the first element) in the interface region between the channel 40 and the etch stop insulating film 90. Any bond state (eg, ionic bond, covalent bond, coordination bond, and / or hydrogen bond) may be formed.

  Note that the etch stop insulating film 90 in this embodiment can be formed by the following film forming method. Specifically, an insulating film can be formed by forming a precursor film of a base material precursor on a substrate by spin coating, and drying, firing and curing. Thereafter, the etch stop insulating film 90 can be formed by performing pattern formation by photolithography and etching.

  As described above, the thin film transistor 300 of this embodiment includes the channel 40 whose main component is an oxide semiconductor containing the first element. In addition, the etch stop insulating film 90 including the second element 92 having a redox potential lower than the redox potential of the first element in the insulating base material is in contact with the channel 40. Therefore, typically, at least in an interface region between the channel 40 (mainly an oxide semiconductor) and the etch stop insulating film 90, the oxygen atom or oxygen ion in the oxide semiconductor and the second element 92 have some bonding state. The possibility of forming will increase. Then, oxygen vacancies in the oxide semiconductor are suppressed or prevented, so that various characteristics of the thin film transistor 300 including the oxide semiconductor, in particular, electrical characteristics and / or reliability can be improved.

<Fourth Embodiment>
FIG. 9 is a schematic cross-sectional view of the thin film transistor 400 in the present embodiment. The thin film transistor 400 of this embodiment is the same as that of the first embodiment except that the gate insulating film 30 of the thin film transistor 100 of the first embodiment is replaced with the gate insulating film 230 of the thin film transistor 200 of the second embodiment. The same as the thin film transistor 100. Therefore, the description which overlaps with 1st Embodiment or 2nd Embodiment may be abbreviate | omitted.

  The insulating film 60 of the present embodiment includes the second element 62 in an inorganic material or an organic material that is a base material having insulating properties. Further, the gate insulating film 230 of the present embodiment includes the second element 232 in an inorganic material or an organic material which is a base material having an insulating property. As shown in FIG. 9, the insulating film 60 is in direct contact with the upper side of the channel 40, and the gate insulating film 230 is in direct contact with the lower side of the channel 40. In addition, the redox potentials of the second elements 62 and 232 contained in the insulating film 60 and the gate insulating film 230 are lower than the redox potential of the first element contained in the channel 40. An example of the base material of the insulating film 60 and the gate insulating film 230 is an insulating film in which the second elements 62 and 232 are included in the polymetalloxane compound.

  Therefore, in the thin film transistor 400 of this embodiment, a part of the second elements 62 and 232 and one of the channels 40 are formed in the interface region between the channel 40 and the insulating film 60 and in the interface region between the channel 40 and the gate insulating film 230. Some bonding state (eg, ionic bond, covalent bond, coordination bond, and / or hydrogen bond) may be formed with some elements (typically, but not limited to, the first element).

  As described above, the thin film transistor 400 of this embodiment includes the channel 40 whose main component is an oxide semiconductor containing the first element. In addition, the insulating film 60 including the second element 62 having a redox potential lower than the redox potential of the first element in the insulating base material, and the redox of the first element in the insulating base material A gate insulating film 230 containing the second element 232 having a redox potential lower than the potential is in contact with the channel 40. Therefore, at least in the interface region between the channel 40 (mainly oxide semiconductor) and the gate insulating film 230 and in the interface region between the channel 40 (mainly oxide semiconductor) and the insulating film 60, the second element 62 having a low redox potential. , 232 typically increases the possibility that an oxygen atom or oxygen ion in the oxide semiconductor and the second element 62, 232 form some bonding state. Then, oxygen vacancies in the oxide semiconductor are suppressed or prevented, so that various characteristics of the thin film transistor 400 including the oxide semiconductor, in particular, electrical characteristics and / or reliability can be improved.

<Fifth Embodiment>
FIG. 10 is a schematic cross-sectional view of the thin film transistor 500 in the present embodiment. The thin film transistor 500 of this embodiment is the same as the thin film transistor 200 of the second embodiment except that the etch stop film 95 is disposed on the channel 40. Therefore, the description which overlaps with 1st Embodiment or 2nd Embodiment may be abbreviate | omitted.

  A known etch stop film can be adopted as the etch stop film 95 of the present embodiment. For example, an etch stop film made of silicon oxide or silicon nitride can be employed.

  Also in the thin film transistor 500 of the present embodiment, the gate insulating film 230 of the present embodiment includes the second element 232 in an inorganic material or an organic material which is an insulating base material. Further, the gate insulating film 230 is in direct contact with the lower side of the channel 40. In addition, the redox potential of the second element 232 contained in the gate insulating film 230 is lower than the redox potential of the first element contained in the channel 40.

  Therefore, in the thin film transistor 500 of the present embodiment, as in the second embodiment, a part of the second element 232 and a part of the channel 40 (representative) in the interface region between the channel 40 and the gate insulating film 230. In particular, some bonding state (eg, ionic bond, covalent bond, coordination bond, and / or hydrogen bond) with the first element, but not limited thereto, may be formed.

  As a result, the presence of the second element 232 having a low oxidation-reduction potential at least in the interface region between the channel 40 (mainly the oxide semiconductor) and the gate insulating film 230 typically represents an oxygen atom in the oxide semiconductor or The possibility that the oxygen ions and the second element 232 form some bonding state is increased. Then, oxygen vacancies in the oxide semiconductor are suppressed or prevented, so that various characteristics of the thin film transistor 500 including the oxide semiconductor, in particular, electrical characteristics and / or reliability can be improved.

<Sixth Embodiment>
FIG. 11 is a schematic cross-sectional view of the thin film transistor 600 in the present embodiment. The thin film transistor 600 of this embodiment is the same as the thin film transistor 300 of the third embodiment, except that the etch stop film 95 is disposed on the etch stop insulating film 90 in the thin film transistor 300 of the third embodiment. Therefore, the description which overlaps with 1st Embodiment, 2nd Embodiment, or 3rd Embodiment may be abbreviate | omitted.

  In this embodiment, if the insulating film 90 for the etch stop of the thin film transistor 300 of the third embodiment cannot sufficiently serve as the etch stop film (for example, if the etching selectivity is relatively small). 2) discloses an example in which the etch stop film 95 is disposed on the etch stop insulating film 90 to assist the role.

Therefore, in the thin film transistor 600 according to this embodiment, the second element 92 (not shown in FIG. 11 for convenience) having a redox potential lower than the redox potential of the first element is provided in the insulating base material. An etch stop insulating film 90 that is in contact with the channel 40. Therefore, typically, at least in an interface region between the channel 40 (mainly an oxide semiconductor) and the etch stop insulating film 90, the oxygen atom or oxygen ion in the oxide semiconductor and the second element 92 have some bonding state. The possibility of forming will increase. Then, oxygen vacancies in the oxide semiconductor are suppressed or prevented, so that various characteristics of the thin film transistor 600 including the oxide semiconductor, in particular, electrical characteristics and / or reliability can be improved.
<Other embodiments>

  By the way, in each above-mentioned embodiment, although thin-film transistor 100,200,300,400,500,600 was illustrated, the use of these thin-film transistors is wide. For example, the thin film transistors 100, 200, 300, 400, 500, and 600 can be applied to semiconductor devices including various active matrix elements, display elements, or electro-optical elements, or microelectromechanical systems. is there.

  As described above, the disclosure of each of the embodiments described above is described for explaining the embodiments, and is not described for limiting the present invention. In addition, modifications within the scope of the present invention including other combinations of the embodiments are also included in the claims.

DESCRIPTION OF SYMBOLS 10 Substrate 20 Gate electrode 30, 230 Gate insulating film 40 Channel 42, 64 Interface region 52 Source electrode 54 Drain electrode 60 Insulating film 62, 232, 92 Second element 70 Lead electrode 260 Insulating film not containing second element 80 Passivation film 90 Insulating film for etch stop 95 Etch stop film 100, 200, 300, 400, 500, 600 Thin film transistor

Claims (11)

A thin film transistor having a gate electrode, an insulating film, a channel mainly composed of an oxide semiconductor, a source electrode, and a drain electrode,
The insulating film includes a compound having one or more second elements having a redox potential lower than the redox potential of the first element contained in the oxide semiconductor, and the insulating film includes the Touching the channel,
Thin film transistor. The insulating film includes a polymer;
The thin film transistor according to claim 1. The polymer is a polymer obtained by polymerizing a compound represented by the following formula (a).
The thin film transistor according to claim 2.

(In the above formula (a), M is Si or Mn, Al, La, Ti, Zr, Sn, Si, Hf, Mg, Ca, Sr, Ba, K, Rb, Li, Nd, Sm, Hf, Ta. , W, Ru, Ir, Nb, Mo, Pd, and V are one or more elements selected from the group consisting of V, and Ra is an organic group having 1 to 8 carbon atoms. And n is a valence of M which is a metal atom, and x is an integer of 0 to (n-1). The oxide semiconductor is In, Ga, Zn, Zr, Mn, Al, La, Ti, Hf, Si, Mg, Ca, Sr, Ba, K, Rb, Li, Nd, Sm, Hf, Ta, W, It is an oxide semiconductor of one or more of the first elements selected from the group consisting of Ru, Ir, Nb, Mo, Pd, and V.
The thin film transistor according to claim 1 or 2. Bottom gate structure,
The thin film transistor according to any one of claims 1 to 4. A thin film transistor according to any one of claims 1 to 5 is provided.
Solid electronic device. A method of manufacturing a thin film transistor having a gate electrode, an insulating film, a channel mainly composed of an oxide semiconductor, a source electrode, and a drain electrode,
The insulating film containing a compound having one or more second elements having a redox potential lower than the redox potential of the first element contained in the oxide semiconductor is disposed so as to be in contact with the channel. Comprising a placement step,
A method for manufacturing a thin film transistor. One or two or more insulating films in contact with a channel mainly including an oxide semiconductor in a thin film transistor and having a redox potential lower than a redox potential of a first element contained in the oxide semiconductor Including a compound having a second element,
Insulating film. The insulating film according to claim 8 is formed.
Curable composition. The thin film transistor according to claim 8 is provided.
Solid electronic device. A film forming step of forming a film containing the curable composition according to claim 9,
Including a firing step of firing the film at 250 ° C. or lower and further firing at 280 ° C. or higher.
A method for forming an insulating film.

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