JP5579848B2 - Semiconductor device, liquid crystal display device having semiconductor device, and method of manufacturing semiconductor device - Google Patents

Description

  The present invention relates to the technical field of a wiring film used for a minute semiconductor device, and more particularly to the technical field of an electrode layer in contact with an oxide semiconductor.

  Recently manufactured electrical products such as FPD (Flat Panel Display) and thin film solar cells require transistors to be uniformly arranged on a wide substrate, and therefore, a semiconductor layer with uniform characteristics can be formed on a large area substrate ( Hydrogenated) amorphous silicon or the like is used.

  Amorphous silicon can be formed at low temperatures and does not adversely affect other materials, but has the disadvantage of low mobility. Recently, it can be formed on large area substrates at low temperatures and has high mobility. Physical semiconductors are attracting attention.

When a transistor is formed using an oxide semiconductor, since the electrode of the metal thin film is in contact with the oxide semiconductor, oxygen in the oxide semiconductor is combined with the metal of the electrode, and oxygen in the oxide semiconductor is extracted to the electrode. It will be. Therefore, there is a problem that oxygen in the oxide semiconductor is insufficient, the physical properties are changed, and mobility is lowered.
In particular, when a protective film is formed over the transistor surface, the oxide semiconductor and the electrode are heated to a high temperature, so that the degree of oxygen extraction by the electrode is increased.

  Such oxygen extraction is generated by a combination of an oxide semiconductor and a copper electrode, and an oxide semiconductor and an aluminum electrode. Oxygen extraction occurs even when an adhesion layer made of a titanium thin film is provided between the oxide semiconductor and the electrode in order to improve the adhesive strength between the oxide semiconductor and the electrode.

JP 2009-99847 A JP 2007-259882 A

  The present invention was created to solve the above-described disadvantages of the prior art, and an object of the present invention is to provide an electrode layer in which the electrode layer does not peel and oxygen atoms in the oxide semiconductor are not extracted into the electrode. There is.

In order to solve the above problems, the present invention provides a semiconductor device having an oxide semiconductor layer and an electrode layer in contact with the oxide semiconductor layer, wherein the electrode layer includes a copper thin film, the copper thin film, An oxygen-containing copper thin film disposed between the oxide semiconductor layers and containing more oxygen than the copper thin film, wherein the oxygen-containing copper thin film has a sputtering gas and a pressure of 3 for the sputtering gas pressure. Sputtering is performed using a target mainly composed of copper in a sputtering atmosphere containing oxygen gas at a pressure of 20% to 20%. A stopper layer made of an oxide insulating thin film is formed on the oxide semiconductor layer. The electrode layer is provided on the stopper layer, and the stopper layer remains without being removed by etching, and the electrode layer on the stopper layer is removed by etching, from the remaining electrode layer. A source electrode layer and the drain electrode layer is separated into had been in contact with the oxide semiconductor layer is formed, the copper thin film is a semiconductor device which is a low-resistance than the oxygen-containing copper film.
This invention is a semiconductor device, Comprising: The said target is a semiconductor device with which the addition metal contained in the range of 12 atomic% or less with respect to the copper atom.
The present invention is a semiconductor device, wherein the electrode layer includes a source electrode layer and a drain electrode layer separated from each other, and the source electrode layer and the drain electrode layer are formed from a source region of the oxide semiconductor layer. The semiconductor device is a transistor that is in contact with a drain region, and in which a gate electrode layer is disposed in a channel region between the source region and the drain region with a gate insulating film interposed therebetween.
The present invention includes the above semiconductor device, a pixel electrode, a liquid crystal disposed on the pixel electrode, and an upper electrode positioned on the liquid crystal, and the pixel electrode is electrically connected to the electrode layer. A liquid crystal display device.
The present invention is a semiconductor device having an oxide semiconductor layer and an electrode layer in contact with the oxide semiconductor layer, wherein the electrode layer includes an oxygen diffusion prevention thin film in contact with the oxide semiconductor layer, and the oxygen layer A semiconductor device manufacturing method for manufacturing a semiconductor device comprising a highly conductive thin film having a lower resistance than a diffusion preventing thin film, wherein the oxygen diffusion preventing thin film has an additive metal of 12 atomic% or less with respect to the number of copper atoms The target contained in the range of is formed by sputtering in a sputtering atmosphere containing a sputtering gas and an oxygen gas having a pressure of 3% to 20% with respect to the sputtering gas, and is formed on the oxygen diffusion prevention thin film. a lower resistance than the oxygen diffusion preventing film, in the method of manufacturing a semiconductor device for forming a highly conductive thin film in contact with the oxygen diffusion preventing film, acid on the surface of the oxide semiconductor layer Forming a material insulating thin film, partially removing the oxide insulating thin film to form a stopper layer made of the oxide insulating thin film, and at least part of the source region in the portion from which the oxide insulating thin film has been removed And at least a part of the drain region, and the electrode layer that contacts the exposed part of the source region and the exposed part of the drain region is formed .
The present invention is a method for manufacturing a semiconductor device, wherein the highly conductive thin film is formed by sputtering the target on which the oxygen diffusion prevention thin film is formed .
The present invention is a method for manufacturing a semiconductor device, wherein a gate insulating film is formed on a channel region between the source region and the drain region of the oxide semiconductor layer, and a gate electrode layer is formed on the gate insulating film. The oxygen diffusion prevention thin film of the electrode layer is formed in contact with the source region and the drain region in a state where the source region and the drain region of the oxide semiconductor layer are exposed. A method for manufacturing a semiconductor device.

The oxygen diffusion prevention thin film of the present invention relaxes the oxygen concentration gradient in the vicinity of the interface between the electrode layer and the oxide semiconductor, so that diffusion transfer from the oxide semiconductor to the electrode layer is prevented, and the oxide semiconductor Changes in composition are suppressed.
When a thin film composed mainly of copper (hereinafter referred to as a copper thin film) is used to form a thin film with high conductivity in the electrode layer (high conductive thin film), the copper thin film is generally wet because it is difficult to dry-etch. The etching method is used, and the oxygen diffusion prevention thin film of the present invention is mainly composed of copper and can be etched with the same etching solution as the high conductivity thin film. Therefore, the electrode can be patterned by a single etching process. it can.

Even when the electrode layer is in contact with the inner peripheral surface of the connection hole formed in the interlayer insulating film or the gate insulating film, the highly conductive thin film in the electrode layer of the present invention has an interlayer insulating film or Since it is in contact with the gate insulating film, diffusion of oxygen atoms from the gate insulating film or the interlayer insulating film to the electrode thin film does not occur.
The copper thin film and the oxygen diffusion preventing thin film can be etched with the same etching solution.

(a)-(c): Process diagram (1) for demonstrating the manufacturing process of the transistor of the 1st example of this invention (a)-(c): Process drawing (2) for demonstrating the manufacturing process of the transistor of the 1st example of this invention (a)-(c): Process drawing for demonstrating the manufacturing process of the transistor of the 1st example of this invention (3) (a), (b): Process diagram for explaining the manufacturing process of the transistor of the first example of the present invention (4) Sectional drawing for demonstrating the transistor of the 1st example of this invention, and the liquid crystal display device of this invention (a)-(c): Process drawing for demonstrating the manufacturing process of the transistor of the 2nd example of this invention Sectional drawing for demonstrating the transistor of the 3rd example of this invention

The IGZO thin film (InGaZnO _x thin film) has excellent electrical characteristics such as high mobility, and has optical characteristics that allow visible light to pass therethrough, so that a transparent film can be formed.
In the case of amorphous, the IGZO thin film can be formed at a low temperature of room temperature to 150 ° C., and can be formed on a plastic substrate, so that it is also suitable as a material for flexible devices.
In the embodiment of the present invention, an amorphous IGZO thin film is employed as the oxide semiconductor, and the electrode material is mainly composed of copper.
FIG. 5 shows a liquid crystal display device according to an embodiment of the present invention, and a cross-sectional view of the transistor 11 of the first example of the present invention is shown together with a liquid crystal display section.
The transistor 11 will be described. In the transistor 11, an elongated gate electrode layer 32 is disposed on the surface of a glass substrate 31, and the gate electrode layer 32 is covered on the gate electrode layer 32 at least in the width direction. As described above, the gate insulating film 33 is disposed.

An oxide semiconductor layer 34 is disposed on the gate insulating film 33, and a source electrode layer 51 and a drain electrode layer 52 are formed on the oxide semiconductor layer 34 so as to be separated from each other at both ends in the width direction.
A recess 55 is provided between the source electrode layer 51 and the drain electrode layer 52, and the source electrode layer 51 and the drain electrode layer 52 are separated from each other by the recess 55. Are respectively connected to the oxide semiconductor layer 34.
The source electrode layer 51 and the drain electrode layer 52 are electrode layers of the present invention.
The source electrode layer 51 and the drain electrode layer 52 have an oxygen diffusion prevention thin film 37 formed on the oxide semiconductor layer 34 and a highly conductive thin film 38 in contact with the oxygen diffusion prevention thin film 37. The highly conductive thin film 38 is preferably not in contact with the oxide semiconductor layer 34. The oxygen diffusion preventing thin film 37 is an oxygen-containing copper thin film, and the highly conductive thin film 38 is a copper thin film. The oxygen-containing copper thin film is a film containing copper as a main component and oxygen. The copper thin film is a film containing copper as a main component, having a lower oxygen content and lower resistance than the oxygen-containing copper thin film.

Reference numeral 36 denotes a stopper layer.
The source electrode layer 51 and the drain electrode layer 52 are constituted by a laminated electrode layer 40 (FIG. 3A) having a two-layer structure mainly composed of copper, which will be described later, and the recess 55 is formed by the laminated electrode layer 40. It is formed by partial etching. The stopper layer 36 is disposed below the laminated electrode layer 40 where the concave portion 55 is formed. Even if the laminated electrode layer 40 is removed by etching, the etching solution may contact the stopper layer 36. The oxide semiconductor layer 34 located below the stopper layer 36 is not contacted.
A protective film 41 is formed on the source electrode layer 51, the drain electrode layer 52, and the recess 55 therebetween to prevent intrusion of moisture and the like. In the recess 55, the oxide semiconductor layer 34 is formed. A protective film 41 is in contact with the upper stopper layer 36.

A pixel electrode 82 is disposed in the liquid crystal display region 14, and a liquid crystal 83 is disposed on the pixel electrode 82. An upper electrode 81 is positioned on the liquid crystal 83, and when a voltage is applied between the pixel electrode 82 and the upper electrode 81, the orientation of the liquid crystal 83 changes and the polarization of light passing through the liquid crystal 83 changes.
When the light polarization changes, the relationship between the light polarization and the polarization filter polarization changes, so the light that has been transmitted through the polarization filter is blocked, or the light that is blocked by the polarization filter. Is translucent.
In this way, when the light polarization property changes, the light transmission state and the light shielding state can be switched, and the light light transmission state and the light shielding state can be controlled by changing the light polarization property. it can.
The pixel electrode 82 is electrically connected to the source electrode layer 51 and the drain electrode layer 52, and voltage application to the pixel electrode 82 is started and ended when the transistor 11 is turned ON / OFF.

  Here, the pixel electrode 82 includes a part of the wiring layer 42 connected to the drain electrode layer 52. The wiring layer 42 is a transparent conductive layer and is made of, for example, ITO. The wiring layer 42 is connected to a wiring layer 84 made of the same thin film as that forming the gate electrode layer 32.

A manufacturing process of the transistor 11 will be described.
In the transistor 11, first, a first conductive thin film is formed on a glass substrate 31 by a vacuum thin film forming method such as a sputtering method or a vapor deposition method, and the first conductive thin film is patterned to form a transistor shown in FIG. As shown in FIG. 2, the gate electrode layer 32 is formed. As the first conductive thin film, a metal thin film having high adhesion to glass can be used.

When the gate electrode layer 32 is formed by patterning the first conductive thin film, the glass substrate surface is exposed except for the portion where the gate electrode layer 32 is located.
As shown in FIG. 1B, a gate insulating film 33 such as SiO ₂ or SiNx is formed on the surfaces of the glass substrate 31 and the gate electrode layer 32. The gate insulating film 33 is patterned into a necessary planar shape.

Next, an oxide semiconductor thin film is formed on the gate insulating film 33 and patterned to form an oxide semiconductor layer 34 composed of the patterned oxide semiconductor thin film, as shown in FIG. .
Next, as shown in FIG. 2A, an oxide insulating thin film 35 is formed over the surface of the oxide semiconductor layer 34 and the surface of the gate insulating film 33 exposed between the oxide semiconductor layers 34. As shown in FIG. 2B, the oxide insulating thin film 35 is patterned to form a stopper layer 36 made of an oxide insulating thin film.

2B, the surface of the stopper layer 36, the surface of the source region portion of the oxide semiconductor layer 34, and the surface of the drain region portion are exposed. Layer 36 covers the surface of the other part.
As described above, the stopper layer 36 is disposed at a position below the multilayer electrode layer 40 where the multilayer electrode layer 40 is removed and the recess 55 is formed in a later step.
This processing object 80 is carried into a vacuum atmosphere inside the sputtering apparatus, and sputtering gas (Ar gas) and oxygen gas are introduced into the vacuum atmosphere of the sputtering apparatus.
The inside of the sputtering apparatus is made into a sputtering atmosphere containing oxygen, and is placed in the sputtering apparatus and contains a copper target containing copper as a main component (88 at% or more). A target containing a metal additive that is a different metal in a range of 12 atomic% or less, including a pure copper target that does not contain a metal additive), while introducing a sputtering gas and an oxygen gas into the inside of the sputtering apparatus Sputtering is performed to form an oxygen diffusion prevention thin film 37 that contacts the surface of the stopper layer 36 and the exposed portions of the source region 71 and the drain region 72 of the oxide semiconductor layer 34. The sputtering gas is a rare gas such as argon gas.
The ratio of copper to metal additive in this oxygen diffusion prevention thin film 37 is the same value as the ratio of copper to metal additive in the target, but includes the case of copper and metal additive (when the metal additive is 0 atomic%). ) Is sputtered in an atmosphere containing oxygen gas, oxygen is combined with copper to produce copper oxide, and the oxygen diffusion preventing thin film 37 contains copper oxide. The oxygen diffusion preventing thin film 37 has a higher concentration of oxygen than the highly conductive thin film 38.
Next, the introduction of the oxygen gas is stopped, and the copper target when the oxygen diffusion prevention thin film 37 is formed while the sputtering gas is introduced is sputtered. As shown in FIG. Then, the highly conductive thin film 38 containing 88 atomic% or more of copper atoms is formed, and the laminated electrode layer 40 composed of the oxygen diffusion preventing thin film 37 and the highly conductive thin film 38 is formed.
When forming the highly conductive thin film 38 by sputtering, oxygen gas is not introduced into the sputtering atmosphere, and copper oxide is not generated in the highly conductive thin film 38, so the conductivity of the highly conductive thin film 38 is high.
The ratio of the metal additive to the copper in the oxygen diffusion prevention thin film 37 and the highly conductive thin film 38 is the same as the ratio of the target on which they are formed, or pure copper may be used only in the highly conductive thin film.

  Thus, in the present invention, the oxygen diffusion prevention thin film 37 is disposed between the high conductive thin film 38 and the oxide semiconductor layer 34, and the high conductive thin film 38 does not contact the oxide semiconductor layer 34. . The oxygen concentration difference between the stacked electrode layer 40 and the oxide semiconductor layer 34 is such that the oxygen diffusion prevention thin film 37 is less in contact with the oxide semiconductor layer 34 than when the highly conductive thin film 38 is in contact with the oxide semiconductor layer 34. And the oxygen diffusion from the oxide semiconductor layer 34 to the stacked electrode layer 40 is prevented.

Further, since the oxygen diffusion preventing thin film 37 contains oxygen, the adhesion of the oxygen diffusion preventing thin film 37 to the oxide is high, and the stacked electrode layer 40 is made of the oxide semiconductor layer 34 or a thin film of another oxide. Does not peel. Further, both of the oxygen diffusion prevention thin film 37 and the highly conductive thin film 38 contain 88 atomic% or more of copper, and the oxygen diffusion prevention thin film 37 and the high conductivity thin film 38 contain the same metal as a main component. Therefore, the adhesion between the thin films is also high. Therefore, the highly conductive thin film 38 is not peeled off from the oxygen diffusion preventing thin film 37.
The oxygen diffusion prevention thin film 37 is also formed on the surfaces of the stopper layer 36 and the oxide semiconductor layer 34, and the highly conductive thin film 38 is formed on the surface of the oxygen diffusion prevention thin film 37. Therefore, the stacked electrode layer 40 does not peel from the stopper layer 36 or the oxide semiconductor layer 34.

The oxygen diffusion prevention thin film 37 has a barrier function against copper atoms, and copper atoms do not diffuse from the oxygen diffusion prevention thin film 37 into the oxide semiconductor layer 34. Also, the high conductivity thin film 38 and the oxide Since the oxygen diffusion prevention thin film 37 is located between the semiconductor layers 34, the copper atoms in the highly conductive thin film 38 are prevented from diffusing by the oxygen diffusion prevention thin film 37, and the copper atoms into the oxide semiconductor layer 34 are detected. Diffusion is prevented.
After the oxygen diffusion prevention thin film 37 and the highly conductive thin film 38 are formed, a resist film is formed on the surface of the highly conductive thin film 38, the resist film is patterned, and on the source region 71 on the surface of the highly conductive thin film 38. A resist film is disposed at a position above the drain region 72. Reference numeral 39 in FIG. 3B indicates the resist film.

In this state, when immersed in an etching solution that dissolves a metal such as copper, the highly conductive thin film 38 exposed between the resist films 39, and the oxygen diffusion prevention thin film 37 positioned immediately below the exposed portion of the highly conductive thin film 38, Are etched by the etching solution.
As a result, the stacked electrode layer 40 remains only on the source region 71 and the drain region 72 covered with the resist film 39, and remains on the source region 71 as shown in FIG. The source electrode layer 51 is formed by the oxygen diffusion prevention thin film 37 and the highly conductive thin film 38, and the drain electrode layer 52 is formed by the oxygen diffusion prevention thin film 37 and the high conductivity thin film 38 remaining on the drain region 72. .
The source electrode layer 51 and the drain electrode layer 52 are separated from each other. A part of the source electrode layer 51 is located on one end of the gate electrode layer 32 and a part of the drain electrode layer 52 is located on the other end. Yes. The edge portion of the source electrode layer 51 and the edge portion of the drain electrode layer 52 are on the stopper layer 36.

  Between the source region 71 and the drain region 72 of the oxide semiconductor layer 34 is a channel region 73, and the gate electrode layer 32 is at a position facing the channel region 73 with the gate insulating film 33 interposed therebetween. In this state, the oxide semiconductor layer 34, the gate insulating film 33, and the gate / source / drain electrode layers 32, 51, 52 constitute the transistor 11.

Next, as shown in FIG. 4A, the resist film 39 is removed, and as shown in FIG. 4B, a protective film 41 made of an insulating film such as SiNx or SiO ₂ is formed. As shown in FIG. A wiring layer in which a connection hole 43 such as a via hole or a contact hole is formed in the protective film 41, and a pattern is formed between the source electrode layer 51 and the drain electrode layer 52 exposed on the bottom surface of the connection hole 43 and the electrode layer of another element. When the voltage is applied to the gate / source / drain electrode layers 32, 51, 52 by connecting at 42, the transistor 11 can operate. Reference numeral 83 denotes a liquid crystal, and reference numeral 81 denotes an upper electrode, which is disposed in a later process.
As described above, since the highly conductive thin film 38 and the oxygen diffusion prevention thin film 37 are etched using an etching solution that erodes the oxide semiconductor layer 34, the etching solution is prevented from contacting the oxide semiconductor layer 34 by the stopper layer 36. However, in the case where an etching solution that does not erode the oxide semiconductor layer 34 is used, the stopper layer 36 is unnecessary because the oxide semiconductor layer 34 can contact the etching solution.

For example, FIG. 6C shows the transistor 12 which is a part of the liquid crystal display device and does not have the stopper layer 36. The liquid crystal display area is omitted.
A process of forming the transistor 12 that does not have the stopper layer 36 will be described with reference to FIG. 6A in which a patterned oxide semiconductor layer 34 is formed on the gate insulating film 33.
Next, the oxygen diffusion prevention thin film 37 and the highly conductive thin film 38 are formed and stacked in this order to form the stacked electrode layer 40, and the stacked electrode layer 40 on the source region 71 of the oxide semiconductor layer 34 has a high height. In a state where the resist film 39 is disposed on the surface of the conductive thin film 38 and the surface of the highly conductive thin film 38 of the stacked electrode layer 40 on the drain region 72 , the oxide semiconductor layer 34 is immersed in an etchant that does not erode, thereby providing high conductivity. The portions of the conductive thin film 38 and the oxygen diffusion prevention thin film 37 that are not covered with the resist film 39 are removed by etching. (Fig. 6 (b))
At this time, the oxide semiconductor layer 34 and the etching solution are in contact with each other, but the oxide semiconductor layer 34 is not eroded.

After removing the resist film 39, as shown in FIG. 6C, when the connection hole 43 is formed in the protective film 41 and the wiring is connected to the source electrode layer 51 and the drain electrode layer 52, the transistor without the stopper layer 36 is obtained. 12 is ready for operation.
In the transistor 12, the gate electrode layer 32, the gate insulating film 33, the oxide semiconductor layer 34, and the source / drain electrode layers 51 and 52 are positioned in this order from the glass substrate 31 side. However, the present invention may be a top gate type transistor 13 as shown in FIG.

  In this transistor 13, an oxide semiconductor layer 34 is partially formed on a glass substrate 31, and a gate insulating film 33 is formed on the glass substrate 31 exposed between the oxide semiconductor layer 34 and the oxide semiconductor layer 34. Is formed.

A gate electrode layer 32 is disposed on a portion of the gate insulating film 33 on the channel region 73, and the gate insulating film 33 is a thin film made of an oxide so as to cover the gate electrode layer 32. An interlayer insulating layer 61 is disposed.
A connection hole 43 is formed in a portion on the source region 71 and a portion on the drain region 72 of the gate insulating film 33 and the interlayer insulating layer 61. On the interlayer insulating layer 61, the oxygen diffusion prevention thin film 37 and the highly conductive thin film 38 are laminated in this order with the surface of the source region 71 and the surface of the drain region 72 exposed at the bottom of the connection hole 43. A two-layer laminated electrode layer is formed.

The stacked electrode layer is patterned, and the source electrode layer 51 in which the oxygen diffusion prevention thin film 37 is in contact with the surface of the source region 71 and the drain electrode layer in contact with the surface of the drain region 72 and separated from the source electrode layer 51. 52, and the transistor 13 is formed.
A protective film 41 is formed on the source electrode layer 51, the drain electrode layer 52, and the interlayer insulating layer 61 exposed therebetween.

  Also in this transistor 13, the highly conductive thin film 38 is not in direct contact with the insulating film made of oxide such as the interlayer insulating layer 61 or the oxide semiconductor layer 34, but through the oxygen diffusion preventing thin film 37. The high conductivity thin film 38 does not peel off due to the high adhesion of the oxygen diffusion prevention thin film 37, and the barrier property of the oxygen diffusion prevention thin film 37 causes the high conductivity thin film 38 or the oxygen diffusion prevention thin film 37 to be separated. The copper atoms are prevented from diffusing into the insulating film or the oxide semiconductor layer 34.

In the following examples and comparative examples, InGaZnO was used for the oxide semiconductor. The oxygen diffusion prevention thin film 37 and the highly conductive thin film 38 were formed by sputtering. Argon gas was used as the sputtering gas, and oxygen was used as the oxidizing gas.
As an example of the present invention, a laminated electrode layer 40 composed of an oxygen diffusion prevention thin film 37 and a highly conductive thin film 38 having the compositions indicated by numbers 1 to 13 in Tables 1 to 3 is formed. The adhesion between the oxide semiconductor layer 34 and the oxide semiconductor layer 34 and the presence or absence of oxygen extraction (reduction) in the oxide semiconductor layer 34 were examined.
Adhesion was judged by applying a predetermined number of adhesive tapes on the surface of the laminated electrode layer 40, then peeling off each adhesive tape, and determining whether the laminated electrode layer 40 was attached to the adhesive tape.
The presence or absence of reduction is determined by performing secondary ion analysis (SIMS) on the stacked electrode layer 40 and the oxide semiconductor layer 34, measuring the oxygen concentration from the surface of the stacked electrode layer 40 to the inside of the oxide semiconductor layer 34, The presence or absence of reducibility was judged from the change in the oxygen content in the vertical direction and the change in the copper oxide content.
In the column of “film configuration” in Tables 1 to 3, the constituent material of the highly conductive thin film 38 is shown on the left side of “/”, and the constituent material of the oxygen diffusion preventing thin film 37 is shown on the right side.
As can be seen from the “film configuration” described in 1 to 13 of Tables 1 to 3, the highly conductive thin film 38 is composed of a pure copper thin film, and the target on which the highly conductive thin film 38 is formed is also Cu 100 atomic%. is there.
The constituent materials of the oxygen diffusion prevention thin film 37 are shown for both cases of containing no oxygen and cases of containing oxygen, and are copper and a metal additive, or copper, a metal additive and oxygen.
In the column of “Alloy addition amount at%”, the content ratio (atomic%) of the metal additive when the copper content is 100 atomic% in the oxygen diffusion preventing thin film 37 is shown. The ratio of the copper and metal additive of the formed target is also this value.
In the column of “oxygen addition amount%”, the pressure of the oxygen gas with respect to the sputtering gas pressure at the time of sputtering is shown. When the amount of oxygen added is A%, “sputtering gas (argon gas) pressure: oxygen gas pressure = 100: A”.
The column of “Adhesion with IGZO film” is an inspection result of the adhesion, and “as depo.” Is an inspection result by measurement after formation of the stacked electrode layer 40 and before heating. aneal "simulates the conditions for forming the protective film 41, and the object to be measured in which the oxide semiconductor layer 34 and the stacked electrode layer 40 are formed without forming the protective film 41 is the temperature at which the protective film 41 is formed. It is a test result by measurement after heating to (here 400 ° C.).
What was to be judged as having poor adhesion due to adhesion of the laminated electrode layer 40 to the peeled adhesive tape, and that adhesion was judged to be high because the laminated electrode layer 40 did not adhere to the adhesive tape. What should be done is indicated by ○.
“Presence / absence of reduction of IGZO film” is a measurement after heating to the formation temperature of protective film 41 (here, 400 ° C.). What should be done is marked with a circle.

As shown in Tables 1 to 3, the laminated electrode layer 40 of which the metal additive is Mg (No. 2) has all “adhesion with the IGZO film” and “reduction occurrence of the IGZO film”. Is the case where the “alloy addition amount at%” is 1 or more and the “oxygen addition amount%” is 3 or more. For the laminated electrode layer 40 of Al (number 3), 5 or more respectively. 3 or more, and from Tables 1 to 3, the minimum values of the necessary values of “alloy addition amount at%” and “oxygen addition amount%” of each metal additive can be read.
Even in the case of pure copper, if the value of “oxygen addition%” is 5 ( pressure %) or more, the adhesion is high and the reduction reaction does not occur. Pressure % is the minimum value of oxygen addition.
In the case of Nos. 2 and 5, if the metal additive is contained at least 1 atomic%, the oxygen content may be at least 3 pressure %.
Further, the maximum content of the metal additive is in the case of a film configuration containing Mg and Al, and the total value of 12% of Mg is 2 atomic% and Al is 10 atomic%. When it is the maximum value of the content of the metal additive, the copper content is the minimum value of 88 atomic%.
When the film configuration of No. 4 is excluded, the maximum value of the metal additive content is 5 atomic% of the film configurations of No. 2 and 3, and in this case, the minimum value of the copper content is 95 atomic% It becomes.

  In addition, in the types of metal additives numbered 1 to 13, even when the “oxygen addition%” is 20 or more, the test results of “adhesion with the IGZO film” and “reduction occurrence of the IGZO film” are Although it is expected to be good (good), the resistance value increases, which is not preferable, so the maximum value may be 20.

The oxide semiconductor is InGaZnO, but the present invention is not limited to this, and includes oxide semiconductors such as ZnO and SnO ₂ .

  Moreover, the oxygen diffusion prevention thin film of the present invention is not limited to the formation method formed by the sputtering method, and includes those formed by other film formation methods such as an evaporation method.

In addition, although the insulating film made of an oxide with which the oxygen diffusion prevention thin film 37 contacts (for example, the stopper layer 36) is an SiO ₂ film, the present invention is not limited to this, and the insulating film made of an oxide. Includes a thin film containing an oxide. Insulating films of the present invention include, for example, SiON films, SiOC films, SiOF films, Al ₂ O ₃ films, Ta ₂ O ₅ films, HfO ₂ films, and ZrO ₂ films.

11, 12, 13 ... Transistor 31 ... Glass substrate 32 ... Gate electrode layer 33 ... Gate insulating film 34 ... Oxide semiconductor layer 36 ... Stopper layer 37 ... Oxygen diffusion prevention thin film 38 ... High conductivity Thin film 43 …… Connection hole 51 …… Source electrode layer 52 …… Drain electrode layer 61 …… Interlayer insulating layer 71 …… Source region 72 …… Drain region 73 …… Channel region 81 …… Upper electrode 82 …… Pixel electrode 83 ……liquid crystal

Claims (7)

An oxide semiconductor layer;
A semiconductor device having an electrode layer in contact with the oxide semiconductor layer,
The electrode layer has a copper thin film, an oxygen-containing copper thin film that is disposed between the copper thin film and the oxide semiconductor layer and contains more oxygen than the copper thin film,
The oxygen-containing copper thin film is formed by sputtering a target mainly composed of copper in a sputtering atmosphere containing a sputtering gas and an oxygen gas having a pressure of 3% to 20% with respect to the pressure of the sputtering gas. And
A stopper layer made of an oxide insulating thin film is provided on the oxide semiconductor layer, the electrode layer is disposed on the stopper layer, and the stopper layer remains without being removed by etching. The upper electrode layer is etched away to form a source electrode layer and a drain electrode layer that are separated from the remaining electrode layer and are in contact with the oxide semiconductor layer,
The said copper thin film is a semiconductor device whose resistance is lower than the said oxygen containing copper thin film.   The semiconductor device according to claim 1, wherein the target contains an additive metal in a range of 12 atomic% or less with respect to copper atoms. The electrode layer has a source electrode layer and a drain electrode layer separated from each other,
The source electrode layer and the drain electrode layer are in contact with the source region and the drain region of the oxide semiconductor layer, respectively.
3. The semiconductor device according to claim 1, wherein a gate electrode layer is disposed in a channel region between the source region and the drain region with a gate insulating film interposed therebetween. . A semiconductor device according to any one of claims 1 to 3, a pixel electrode, a liquid crystal disposed on the pixel electrode, and an upper electrode positioned on the liquid crystal,
The pixel electrode is a liquid crystal display device electrically connected to the electrode layer. An oxide semiconductor layer;
A semiconductor device having an electrode layer in contact with the oxide semiconductor layer,
The electrode layer is a semiconductor device manufacturing method for manufacturing a semiconductor device comprising an oxygen diffusion prevention thin film in contact with the oxide semiconductor layer and a highly conductive thin film having a lower resistance than the oxygen diffusion prevention thin film. ,
The oxygen diffusion prevention thin film includes a target containing an additive metal in a range of 12 atomic% or less with respect to the number of copper atoms, a sputtering gas, and an oxygen gas having a pressure of 3% to 20% with respect to the sputtering gas. Formed by sputtering in a sputtering atmosphere containing
In the method of manufacturing a semiconductor device, on the oxygen diffusion prevention thin film, a low-resistance than the oxygen diffusion prevention thin film and forming a highly conductive thin film in contact with the oxygen diffusion prevention thin film ,
An oxide insulating thin film was formed on the surface of the oxide semiconductor layer, the oxide insulating thin film was partially removed to form a stopper layer made of the oxide insulating thin film, and the oxide insulating thin film was removed A method of manufacturing a semiconductor device, wherein at least a part of a source region and at least a part of a drain region are exposed in a part, and the electrode layer that contacts the exposed part of the source region and the exposed part of the drain region is formed .   6. The method of manufacturing a semiconductor device according to claim 5, wherein the highly conductive thin film is formed by sputtering the target on which the oxygen diffusion preventing thin film is formed. Forming a gate insulating film over a channel region between the source region and the drain region of the oxide semiconductor layer;
A gate electrode layer is disposed on the gate insulating film,
Wherein in the state of exposing the source region and the drain region of the oxide semiconductor layer, the oxygen diffusion prevention film of the electrode layer, according to claim 5 or claim to form in contact with the drain region and the source region The method for manufacturing a semiconductor device according to any one of items 6 .

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