KR101729090B1 - Method of manufacturing semiconductor device, and semiconductor device - Google Patents

Abstract

There is a problem that the oxide semiconductor surface layer is etched when etching an oxide semiconductor containing zinc as a main component, resulting in an excessive side etching.
In order to solve such a problem, by pretreating the surface of the oxide semiconductor with a pretreatment liquid capable of selectively etching only the oxidized zinc phase present on the surface of the oxide semiconductor, the pores formed at the interface between the photoresist and the oxide semiconductor are suppressed, The amount of side etching after the semiconductor etching process is suppressed.

Description

Technical Field [0001] The present invention relates to a method of manufacturing a semiconductor device,

The present invention relates to a method of manufacturing a semiconductor device and a semiconductor device, and more particularly, to a method of manufacturing an oxide semiconductor device and a semiconductor device having an oxide semiconductor transistor.

In a liquid crystal display using a thin film transistor as a pixel switch, a liquid crystal display employing amorphous silicon (amorphous silicon) as a channel layer of the thin film transistor is the mainstream. However, it is difficult to realize a high requirement of a liquid crystal display as a channel layer employing amorphous silicon. In recent years, oxide semiconductors having better characteristics than amorphous silicon have been attracting attention as thin film transistors for organic EL (electroluminescence) backplanes which are self-luminous devices and require large current driving.

Unlike amorphous silicon which is formed by chemical vapor deposition (CVD), oxide semiconductors can be formed by a sputtering method. Therefore, the oxide semiconductors are excellent in the homogeneity of the film and can meet the demands for enlargement and fineness of the liquid crystal display. In addition, the oxide semiconductor has better on-characteristics than amorphous silicon and is advantageous for high brightness, high contrast, and high-speed driving. In addition, the oxide semiconductor can be expected to reduce power consumption (power saving). Further, the sputtering method can form a film with a high uniformity in a large area and can form a film at a lower temperature as compared with the chemical vapor deposition method. Therefore, an advantage that a material having low heat resistance can be selected as a material constituting the thin film transistor have.

As an oxide semiconductor preferable for a channel layer of a liquid crystal display, for example, an indium gallium zinc composite oxide (hereinafter referred to as " IGZO (registered trademark) ") is known, and a semiconductor device using IGZO is also known (for example, Patent Document 1).

Since IGZO is insufficient in the resistance to the electrode working process, it is difficult to manufacture the IGZO at a low cost such as the formation of an etching stop layer. On the other hand, an oxide semiconductor material having a high resistance to an electrode working process such as an indium tin zinc composite oxide (hereinafter referred to as ITZO) and a zinc tin composite oxide (hereinafter referred to as ZTO) has also been proposed (for example, 2 and 3). In particular, ZTO is a promising oxide semiconductor material in terms of cost and sustainability because it rarely uses rare metals or elements with high industrial utilization rates.

Japanese Patent Application Laid-Open No. 2006-165532 Japanese Patent Application Laid-Open No. 2008-243928 Japanese Patent Laid-Open Publication No. 2012-033699

In the above-mentioned prior art, if a liquid crystal display is manufactured by using a thin film transistor in which an oxide semiconductor containing zinc oxide as a main component is adopted as a channel layer, the following problems exist in the manufacturing process. Here, the main component of zinc oxide means that the zinc oxide contains 0.5 (50 at.%) Or more of the composition ratio (the ratio of the number of constituent atoms when the whole is taken as 1) It is only necessary to contain zinc oxide at a composition ratio of 0.5 or more in a composition sampled at an arbitrary point in the layer.

FIG. 2 is a sectional view showing a manufacturing process of a thin film transistor by an oxide semiconductor containing zinc oxide as a main component (for example, ZTO containing zinc oxide in a composition ratio of 0.5 or more). In the manufacturing process of the thin film transistor, the channel layer made of the oxide semiconductor film 2 containing zinc oxide is formed on the substrate 3, and the region for forming the channel is covered with the photoresist layer 1 (A). Next, the photoresist layer 1 is exposed and developed to be processed into a mask shape (B), and etched through a mask (C).

At this time, a zinc oxide (zinc oxide) phase present on the surface of the oxide semiconductor film 2 is easily processed in the developing process of the photoresist layer 1, thereby forming a large side etching with a thickness of several micrometers . Normally, when a photoresist is formed, the outermost surface of the oxide semiconductor is subjected to ozone treatment or surface modifier treatment, whereby the photoresist and the oxide semiconductor are firmly adhered to each other. However, in the case of an oxide semiconductor containing zinc oxide as a main component, since an oxidized zinc oxide is easily present on the surface due to weak acids and weak alkalies and depending on the conditions, the weakly alkaline chemical for developing the photoresist The surface of the oxide semiconductor film 2 is also etched. The portion of the oxide semiconductor film to be removed by the developer during photoresist development is indicated by 4 (B). In severe cases, the photoresist may peel off. In this state, etching is further performed to process the oxide semiconductor film 2, thereby further enlarging the side etching. The side etching area further advanced by the oxide semiconductor etching is represented by 5 (C).

Due to this side etching, it is difficult to form the device as designed and the production yield is lowered. This phenomenon appears particularly specific to oxide semiconductor materials having a high zinc oxide content. On the other hand, a passive layer (passivation layer) such as indium oxide, gallium oxide, or tin oxide, that is, an oxide semiconductor material which is prone to form an oxide film that is resistant to corrosion, is hardly visible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems found by the inventors of the present invention, and it is an object of the present invention to provide a method of manufacturing an oxide semiconductor device in which side etching is suppressed at the time of processing an oxide semiconductor film containing zinc oxide as a main component, And to provide a device.

In order to achieve the above object, the present invention provides a method of manufacturing a semiconductor device using an oxide semiconductor film containing zinc oxide at a composition ratio of 0.5 or more, wherein the oxide semiconductor film is formed by a first step, A third step of forming a mask for processing the oxide semiconductor film by processing the mask material film and a fourth step of processing the oxide semiconductor film by using a mask, Processing step of removing at least a part of the surface of the oxide semiconductor film by using a treatment liquid having a higher etching rate of the oxidized zinc oxide phase (rare earth oxide phase) than the etching rate of the oxide semiconductor film itself before the second step. By this pretreatment, a mask material film can be formed after the oxidized oxide film on the surface of the oxide semiconductor film is removed. Therefore, the mask material film and the semiconductor film are firmly bonded, and the side etching by the subsequent etching process can be reduced.

As a preferred specific example, the pretreatment step is to clean the oxide semiconductor film with a treatment solution having a hydrogen ion index (pH) of 3 or more and 14 or less. The treatment liquid may be selected so that the etching rate of the oxidized-heteroatom portion in the oxide semiconductor film is faster than the other portions.

A semiconductor device according to the present invention includes a substrate, a channel layer formed of an oxide semiconductor film formed on the substrate directly or through another layer and patterned by etching, and a channel layer formed directly or through another layer Source and drain electrodes electrically connected to each other, and a gate electrode disposed on the channel layer. The oxide semiconductor film is formed of an oxide containing zinc oxide as an average value of the composition ratio of 0.5 or more as an average value of the entire film and at least a part of the surface of the oxide semiconductor film which is in contact with the other film on the opposite side of the substrate has an etching rate A pretreatment step using a treatment liquid having a higher etching rate on the zinc oxide phase is performed so that the composition ratio of zinc oxide is smaller than the composition ratio of the other metal oxides. In this way, since the oxidized zinc phase present on the surface of the oxide semiconductor film is small, bonding between the etching mask used in the manufacturing process and the surface of the oxide semiconductor film becomes strong, and side etching can be suppressed. Thus, a semiconductor device with high processing accuracy is obtained.

According to the present invention, there is provided a method of manufacturing a high-yield semiconductor device using a thin film transistor using an oxide semiconductor material containing zinc oxide. In addition, there is provided a semiconductor device with improved processing precision produced by the method.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process sectional view for explaining a process in which side etching is suppressed by removing an oxide silver oxide on the surface of an oxide semiconductor film containing zinc oxide in advance by the pretreatment of the embodiment of the present invention. FIG.
2 is a process sectional view for explaining a process in which an oxide semiconductor film containing zinc oxide undergoes side etching by etching an oxide semiconductor oxide during the formation of a photoresist during oxide semiconductor etching.
3 is a process cross-sectional view illustrating a manufacturing process of a bottom gate top contact type thin film transistor according to an embodiment of the present invention.
FIG. 4 is a process sectional view for explaining a manufacturing process of a bottom gate top contact type thin film transistor according to an embodiment of the present invention (continuing). FIG.
5 is a chart showing a surface treatment effect when the treatment with the alkaline treatment liquid of the embodiment is applied to the ZTO oxide semiconductor film.
6 is a chart showing the surface treatment effect when the treatment with the weakly acidic treatment liquid of the embodiment is applied to the ZTO oxide semiconductor film.
Fig. 7 is a chart comparing the amount of side etching in the case of performing the pretreatment of the embodiment and the case of not performing the pretreatment in the embodiment.

Embodiments will be described in detail with reference to the drawings. It should be noted, however, that the present invention is not construed as being limited to the description and numerical values of the embodiments described below. It is easily understood by those skilled in the art that the specific configuration can be changed without departing from the spirit and scope of the present invention.

The notation such as " first, " " second, " " third, " and the like in the present specification are given for identification of components and are not necessarily limited to numbers or orders.

The position, size, range, and the like of each structure shown in the drawings and the like may not represent the actual position, size, range, or the like for the sake of simple understanding. Therefore, the present invention is not necessarily limited to the position, size, range and the like disclosed in the drawings and the like.

The functions of the "source" and the "drain" of the transistor may be changed when transistors having different polarities are employed, when the direction of the current changes in a circuit operation, and the like. Therefore, in this specification, the terms "source" and "drain" can be used interchangeably.

[Example 1]

Hereinafter, an example of a method for manufacturing an oxide semiconductor device of the present invention will be described. The oxide semiconductor film of this embodiment is a ZTO containing zinc oxide in a composition ratio of 0.5 or more with respect to the whole oxide semiconductor. When the content ratio of zinc oxide is less than 0.5, the processability of etching deteriorates. Therefore, the content ratio of 0.5 or more is preferable in the production process.

1 is a cross-sectional view showing an example of a method for producing an oxide semiconductor of the present invention.

An oxide semiconductor film 11 containing zinc oxide is formed on the substrate 12. [ On the surface of the oxide semiconductor film 11, an oxidized oxide film is formed. This oxide blue oxide film can be removed by pretreating the oxide semiconductor film 11 with an aqueous solution. The oxidized zinc oxide removed by the pretreatment of the present invention is represented by 10 (A).

A metal oxide other than zinc remains on the surface of the oxide semiconductor film 11 after the removal of the zinc oxide layer to form a passive phase thereon. The passive phase is less susceptible to erosion than oxidized zinc oxide. Therefore, the photoresist 13 formed on the passive phase is firmly bonded to the oxide semiconductor film 11 (B).

The photoresist 13 is formed as a mask pattern and etched (C). As a result, the side etching 14 can be suppressed (D).

The oxide semiconductor film of this embodiment is, for example, an oxide semiconductor containing zinc oxide in a composition ratio of 0.5 or more with respect to the entire oxide semiconductor film. As a preferable specific example, ZTO is a zinc oxide containing 0.6 to 0.7 in composition ratio with respect to the whole oxide semiconductor. As the aqueous solution pretreating the oxidized zinc oxide, a treatment solution having a hydrogen ion index (pH) of 3 or more and 14 or less can be used. As a more preferable specific example, it can be appropriately selected in a weak acid or an alkaline aqueous solution according to the target zinc oxide phase treatment rate.

In the step of forming the oxide semiconductor film 11 in the above process, a target containing an oxide semiconductor material is sputtered to form an oxide semiconductor film (hereinafter, referred to as " 11) can be formed. The process of forming the oxide semiconductor film is disclosed in, for example, Japanese Patent Laid-Open Publication No. 2012-033699. The step of forming the mask material film 13 on the oxide semiconductor film 11 to form the mask includes the steps of forming a mask material film 13 as a photoresist film by applying a photoresist material to the oxide semiconductor film 11, A known technique of obtaining a desired mask shape by developing using a photoresist developer can be used. A process of processing an oxide semiconductor film by using a mask may be a known technique of etching the oxide semiconductor film by using an etching solution and processing the oxide semiconductor film into a desired shape depending on the presence or absence of a mask formed thereon.

As described above, in the present embodiment, by employing as the pretreatment a process of selectively etching only the zinc oxide film existing on the outermost surface of the oxide semiconductor film containing zinc oxide as a main component, side etching is suppressed and good processing precision is obtained Loses.

Generally, on the surface of an oxide semiconductor containing zinc oxide as a main component, there exists an oxidized zinc oxide which is easily dissolved by wet etching. Zinc oxide is an amphoteric oxide and readily dissolves in both acidic and alkaline. Therefore, when the photoresist is developed with an alkaline developing solution, the surface layer of the oxide semiconductor near the interface with the photoresist may be etched. When the oxide blue oxide layer is removed to a depth of several nm, a passivation layer is formed and covered with the passivation layer, so that the oxide blue oxide layer is not easily etched by the developer of the photoresist. However, as described above with reference to Fig. 2, when the mask material such as photoresist and the oxide silver oxide on the interface of the oxide semiconductor film are removed in the developing process, gaps are formed between the mask and the oxide semiconductor film. Therefore, during the etching process of the oxide semiconductor film, excessive side etching occurs in this gap. Therefore, if the oxide blue phase existing on the surface of the oxide semiconductor film can be selectively removed in advance, such a problem will not occur. That is, if the surface portion of the oxide semiconductor film is removed before forming the photoresist, the portion that is likely to be dissolved is already removed in the pretreatment. Therefore, when the photoresist layer is formed on the pretreated oxide semiconductor film, the photoresist layer is formed on the surface of the oxide semiconductor film which is not easily etched by the developer. Therefore, in the developing step of the photoresist, the gap formed between the oxide semiconductor film and the photoresist can be reduced. Thus, in the present embodiment, cleaning is performed using an aqueous solution immediately before forming the photoresist in the pretreatment. Such an aqueous solution may have a higher etching rate of the zinc oxide phase than the etching rate of the oxide semiconductor itself containing zinc oxide as a main component such as ZTO. Ideally, an aqueous solution which does not etch the oxide semiconductor itself but gradually etches only the oxide semiconductor phase is preferable. After the oxidized zinc oxide is etched, a passivation layer mainly composed of other metal oxide is formed, so that it is possible to effectively remove only the oxidized zinc oxide. The oxide semiconductor film to be removed at this time depends on the concentration of the solution used in the treatment and the treatment temperature, but is approximately 1 to 3 nm and has almost no influence on device characteristics.

Since the oxide semiconductor layer is already removed and the surface of the oxide semiconductor is covered with the passivation layer after the pretreatment is performed in advance, the photoresist is coated, exposed, and developed, Side etching does not occur. In addition, excessive side etching does not occur even in the subsequent etching treatment of the oxide semiconductor film.

[Example 2]

As described above, the zinc tin composite oxide (ZTO) is an excellent oxide semiconductor material. Particularly, it is preferable that zinc oxide is contained in a composition ratio of 0.5 or more in terms of the performance as a semiconductor device or the viewpoint of the process. More preferably, the composition contains zinc oxide in a composition ratio of 0.6 to 0.8.

In this embodiment, a manufacturing process of a thin film transistor using an oxide semiconductor film of ZTO having a composition of zinc oxide of 0.6 to 0.7 will be described.

Figs. 3 to 4 are sectional views showing the manufacturing method of this embodiment. In a flat panel display or the like, since a bottom gate top contact type thin film transistor is usually used in many cases, this structure will be described as an example here. The effect of the present invention is the same in a device that forms a mask with a photoresist or the like on an oxide semiconductor film even with other types of thin film transistors.

First, a metal thin film 21 such as Mo is formed on a glass substrate 22 serving as a substrate, and then a mask 20 of a gate pattern is formed by photoresist (A).

The gate electrode 23 having a thickness of 50 to 100 nm is formed by etching through the mask 20 (B).

Thereafter, an insulating film 24 of silicon oxide or the like serving as a gate insulating film is formed to a thickness of about 10 nm on the entire surface, and the oxide semiconductor film 25 is further formed by sputtering (C). A method of forming an oxide semiconductor film by sputtering is described in, for example, Japanese Patent Laid-Open Publication No. 2012-33699. The thickness of the oxide semiconductor film 25 is selected in the range of, for example, 20 to 100 nm, and is set to 50 nm as an example here.

A photoresist layer 26 to be a channel pattern is formed on the oxide semiconductor film 25 (D).

In order to process the channel region, a mask pattern 27 is formed by drawing a channel pattern on the photoresist layer 26 by a well-known method, exposing and developing the channel pattern (E).

The channel 28 is formed by etching using the mask 27 (F).

A source / drain electrode 31 is formed by forming a metal thin film 29 of Mo or Cu as a source / drain electrode to a thickness of 100 to 300 nm and etching the photoresist as a mask 30 (G) (H). And further covered with a protective film 32 to complete the basic structure of the oxide thin film transistor (I). The protective film 32 is a single-layer or multilayer film including, for example, a 100 nm silicon oxide layer.

After the formation of the oxide semiconductor film 25, a pretreatment for removing the oxide semiconductor film formed on the surface of the oxide semiconductor film 25 is performed before formation of the photoresist layer 26 in the above process.

In this embodiment, the oxide semiconductor itself and the zinc oxide are pretreated with a treatment liquid having a different etching rate. Ideally, the etching of the oxide semiconductor itself such as ZTO is hardly progressed, but an alkaline aqueous solution capable of removing only the oxidized zinc oxide is used as the pretreatment solution, and the surface of the oxide semiconductor surface containing zinc oxide as a main component such as ZTO Processing is performed. As the alkaline aqueous solution, an alkaline processing solution having a hydrogen ion index (pH) of 8 to 14 can be used. Ammonia, and other amines is a typical example and may be selected in consideration of safety, cost, ease of handling, and the like.

Here, 0.3% aqueous ammonia solution and 2.3% TMAH (tetramethylammonium hydroxide) aqueous solution are used as the mass% concentration. Each of them is immersed at 25 DEG C for about 30 seconds to remove the oxide silver oxide from the surface of the oxide semiconductor, and is covered with the passivation layer which is strong by the remaining tin oxide. The depth of the oxide semiconductor film which is reduced at this time is about 1 to 2 nm, which is not a fluctuation affecting the performance of the thin film transistor. By performing photoresist coating, exposure, and development after the pretreatment with these aqueous solutions, side etching in the interface between the photoresist and the oxide semiconductor as described above can be reduced, and the oxalic acid etching solution It is possible to suppress the etching by the proper side etching by the etching. By performing the pretreatment of this embodiment, it is possible to manufacture thin film transistors and their arrays at a good yield by preventing deterioration in dimensional accuracy during ZTO processing.

When the source / drain electrodes 31 are processed by this process, wet etching with an acid is often performed in order to process the metal electrodes. In the case of an oxide semiconductor material such as ZTO used in the present embodiment, even if the surface of the oxide semiconductor film 25 is exposed to the etching liquid after metal processing is completed, the oxide semiconductor film which is a channel layer is not etched by the passivation layer of tin oxide formed previously . This manufacturing method is called a channel etching process and is a manufacturing method contributing to reduction in the number of masks and cost reduction. On the other hand, in IGZO or the like shown in the background art, there is no resistance to the etching solution of the metal electrode, which is etched at the time of processing the source and drain electrodes, and therefore, this process can not be manufactured. This is an advantage of the oxide semiconductor material that realizes a channel etching process such as ZTO.

For comparison, a comparative example in the case where the pretreatment of this embodiment is not applied will be described below. As described above, in the case of an oxide semiconductor material containing zinc oxide as a main component, such as ZTO, since the zinc oxide phase existing on the surface is easily dissolved in an aqueous solution of weakly acidic or alkaline, excessive side etching . Without applying the pretreatment of the present embodiment, for example, in the case of ZTO having a composition ratio of zinc oxide of 0.6 to 0.7, by the treatment of an alkaline developer for developing a photoresist, the photoresist and the oxide semiconductor film A gap of about 1 to 3 nm is generated at the interface. In addition, when the oxide semiconductor channel layer is processed by a wet etching solution such as an oxalic acid-based etching solution, etching proceeds from the inter-electrode gap that has already occurred at the time of patterning the photoresist, Lt; / RTI > As a result of actually being tested in such a system, in the processing of an oxide semiconductor film having a thickness of about 50 nm, side etching of about 3 m on one side from the end face of the photoresist was formed.

Fig. 5 is a chart showing the effect of the surface treatment in the case where the pretreatment by the various alkaline processing solutions of this embodiment is applied to the ZTO oxide semiconductor film.

TMAH is a tertiary amine and is used as a main component of a photoresist developing solution. Therefore, the photoresist developing solution can be used as a pretreatment solution in this embodiment to make the process more efficient. The concentration of the alkali base material is not particularly limited as far as the etching of the oxide semiconductor film does not proceed, and it can be suitably controlled in consideration of the applied oxide semiconductor material, process solution life, productivity and the like.

Although the channel etching process of the bottom gate top contact structure, typical materials and process techniques have been described herein, even when various combinations of these and combinations thereof are used, various problems caused by the etching of the zinc oxide It is possible to apply the pretreatment method of the present invention.

[Example 3]

Although the alkaline pretreatment liquid is described in Embodiment 2, such an effect can be expected even with a slightly acidic liquid. Next, an example in which a slightly acidic aqueous solution is used as the pretreatment liquid as a pretreatment liquid for the surface of an oxide semiconductor containing zinc oxide as a main component, such as ZTO, will be described.

Fig. 6 is a chart showing the effect of the surface treatment when the pretreatment by the slightly acidic treatment liquid of this embodiment is applied to the ZTO oxide semiconductor film.

As the slightly acidic aqueous solution, a slightly acidic treatment solution having a hydrogen ion index (pH) of 3 or more and 6 or less can be used. As a typical example, the slightly acidic treatment liquid is a liquid containing at least one of boric acid, acetic acid, citric acid, and other carboxylic acids. Or a liquid containing at least one of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, and hydrofluoric acid.

A 0.01% hydrochloric acid aqueous solution, a 0.01% sulfuric acid aqueous solution, a 0.04% aqueous phosphoric acid solution, a 0.01% nitric acid aqueous solution, a 0.01% aqueous hydrofluoric acid solution, a 0.1% aqueous acetic acid solution, 1.0% citric acid aqueous solution, and 0.5% boric acid aqueous solution. Each of them is immersed at 25 DEG C for about 30 seconds to remove the oxide silver oxide from the surface of the oxide semiconductor and to be covered with a strong passivation layer. At this time, the reduced oxide semiconductor film has a depth of about 2 to 3 nm, which is not a fluctuation affecting the performance of the thin film transistor. By performing photoresist coating, exposure, and development after the pretreatment with these aqueous solutions, side etching in the interface between the photoresist and the oxide semiconductor as described above can be reduced, and the oxalic acid etching solution It is possible to suppress the etching by the proper side etching by the etching. By performing the pretreatment of this embodiment, it is possible to manufacture thin film transistors and their arrays at a good yield by preventing deterioration in dimensional accuracy during ZTO processing.

In this embodiment, diluted strong acid, boric acid as a weak acid, acetic acid such as a typical carboxylic acid, and citric acid are used as a weakly acidic pretreatment solution. However, other weakly acidic solutions may be used as an adjustable acid such as carbonic acid or other carboxylic acid The same effect can be expected. The concentration of the weakly acidic pretreatment liquid is not a problem as long as the pH is close to 3 to 6, and even if the oxide semiconductor film is not etched, deviating from this value has no effect on the effect.

Also in this embodiment, as in the second embodiment, it is possible to appropriately change the structure according to the structure and the process of the device.

[Example 4]

The pretreatment solutions of Examples 2 and 3 were used for pretreatment of the step of forming a photoresist pattern on the surface of ZTO, and then the ZTO layer was processed (100% overetching) using an oxalic acid-based etching solution.

Fig. 7 is a graph showing the amount of side etching when the above-mentioned pretreatment is applied to the surface of a ZTO oxide semiconductor to perform etching processing, as an effect of an embodiment of the present invention. It can be seen that the side etching amount in the range of 2.5 to 3.0 mu m is reduced to about one-tenth when the pretreatment is not performed. In the pretreatment of the above embodiments, so-called wet cleaning for treating the oxide semiconductor with a liquid can be carried out by a known method and apparatus. For example, immersion in a liquid (for example, Japanese Unexamined Patent Application Publication No. 2002-158200) in which a wafer is immersed in a liquid over the entire surface or a single wafer type in which a substrate is sprayed with a liquid (for example, Japanese Patent Application Laid- -249477), which can be suitably applied in the process of the pretreatment.

[Example 5]

According to the manufacturing method of the present invention described in the above embodiment, the manufactured semiconductor device includes the transistor structure shown in (I) of FIG. The oxide semiconductor film 25 of this transistor is, for example, ZTO having a composition ratio of zinc oxide of 0.6 to 0.7. In this oxide semiconductor film 25, the oxide blue phase near the surface was removed by the previous steps (pre-steps) described in Examples 1 to 4, and instead of the oxide phase of another metal (in the case of ZTO, Phase). This characteristic can be confirmed by comparing the composition of the oxide semiconductor film 25 in the vicinity of the boundary with the other film and the composition of the oxide semiconductor constituting the oxide semiconductor film 25. [ For confirmation, the average value of the composition at a plurality of sample points inside the oxide semiconductor film, the composition near the center of the film thickness, or the target for forming the oxide semiconductor film (strictly speaking, the composition of the target and the composition of the oxide semiconductor film formed are the same ) Can be compared with the composition in the vicinity of the surface of the oxide semiconductor film (for example, within a range of 2 to 3 nm in depth from the surface).

The present invention is not limited to the above-described embodiment, but includes various modifications. For example, it is possible to replace part of the constitution of any embodiment by the constitution of another embodiment within the scope of not deviating from the gist of the invention, and to add the constitution of another embodiment to the constitution of any embodiment It is possible. In addition, it is possible to add, delete, or substitute another configuration with respect to a part of the configuration of each embodiment.

The present invention can be applied to the field of manufacturing semiconductor devices.

1: photoresist layer
2: An oxide semiconductor film containing zinc oxide
3: substrate
25: oxide semiconductor channel layer
27: Photoresist layer (channel pattern)
28: channel
30: Photoresist layer (source / drain pattern)
29: source / drain electrode layer
31: source / drain electrode
32: Protective layer

Claims (15)

A manufacturing method of a semiconductor device using an oxide semiconductor film containing zinc oxide at a composition ratio of 0.5 or more,
A first step of forming the oxide semiconductor film,
A second step of forming a mask material film on the oxide semiconductor film,
A third step of processing the mask material film to form a mask for processing the oxide semiconductor film,
And a fourth step of processing the oxide semiconductor film using the mask,
At least a part of the surface of the oxide semiconductor film is removed by using a treatment liquid having a higher etching rate of the oxide zinc oxide phase (lead oxide phase) than the etching rate of the oxide semiconductor film itself after the first step and before the second step And a pre-treatment step of pre-treating the semiconductor device. The method according to claim 1,
Wherein the pretreatment step comprises treating the oxide semiconductor film with a treatment solution having a hydrogen ion index (pH) of 3 or more and 14 or less. 3. The method of claim 2,
Wherein the pretreatment step comprises treating the oxide semiconductor film with an alkaline processing solution having a hydrogen ion index (pH) of 8 or more and 14 or less. The method of claim 3,
Wherein the alkaline processing solution is a liquid containing at least one of ammonia and other amines. 3. The method of claim 2,
Wherein the pretreatment step comprises treating the oxide semiconductor film with a weakly acidic treatment solution having a hydrogen ion index (pH) of 3 or more and 6 or less. 6. The method of claim 5,
Wherein the weakly acidic treatment liquid is a liquid containing at least one of boric acid, acetic acid, citric acid, and other carboxylic acids. 6. The method of claim 5,
Wherein the weakly acidic treatment liquid is a liquid containing at least one of hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, and hydrofluoric acid. The method according to claim 1,
Wherein the oxide semiconductor film is made of a zinc-tin composite oxide containing zinc oxide in a composition ratio of 0.5 or more. 9. The method of claim 8,
Wherein the zinc-tin composite oxide contains zinc oxide in a composition ratio of 0.6 to 0.8. The method according to claim 1,
The first step of forming the oxide semiconductor film is a step of sputtering a target containing an oxide semiconductor material to form the oxide semiconductor film by atoms emitted from the target,
A second step of forming a mask material film on the oxide semiconductor film is a step of forming a mask material film as a photoresist film by disposing a photoresist material on the oxide semiconductor film,
The third step of processing the mask material film to form a mask for processing the oxide semiconductor film is a step of developing the photoresist film using a photoresist developer,
The fourth step of processing the oxide semiconductor film by using the mask is a step of etching the oxide semiconductor film by using an etchant and processing the oxide semiconductor film into a desired shape according to the presence or absence of the formed mask . 11. The method of claim 10,
Wherein a solution of the same kind as that of the photoresist developer is used as a treatment liquid in the pretreatment step. A semiconductor device comprising: a substrate; a channel layer formed of an oxide semiconductor film formed on the substrate directly or through another layer and patterned by etching; a source / drain electrode electrically connected to the channel layer directly or through another layer; And a transistor constituted by a gate electrode disposed on the channel layer,
The oxide semiconductor film is composed of an oxide containing zinc oxide as an average value of at least 0.5 in composition ratio and at least a part of the surface of the oxide semiconductor film which is in contact with another film on the opposite side of the substrate from the oxide semiconductor film itself Wherein a composition ratio of zinc oxide is smaller than a composition ratio of other metal oxides by carrying out a pretreatment step using a treatment liquid having a higher etching rate of zinc oxide than the etching rate of zinc oxide. 13. The method of claim 12,
Wherein the oxide is a zinc-tin composite oxide. 14. The method of claim 13,
Wherein the zinc-tin composite oxide contains zinc oxide as an average value of the whole film in a composition ratio of 0.6 to 0.8. 14. The method of claim 13,
And the other metal oxide is tin oxide.

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