JP5420964B2 - Display device and Cu alloy film used therefor - Google Patents

Description

  The present invention relates to a display device and a Cu alloy film used therefor, and in particular, in a thin film transistor (hereinafter sometimes referred to as “TFT”) of a display device, an insulating film or a semiconductor film (SiN film). And a flat panel display (display device) such as a liquid crystal display (liquid crystal display device) or an organic EL display in which the Cu alloy film is used in the TFT. Hereinafter, a liquid crystal display device will be described as an example of the display device, but the present invention is not intended to be limited to this.

  Liquid crystal display devices used in various fields ranging from small mobile phones to large televisions exceeding 100 inches have TFTs as switching elements, transparent pixel electrodes, wiring portions such as gate wirings and source-drain wirings, and the like. A TFT substrate provided with a semiconductor film such as amorphous silicon (a-Si) or polycrystalline silicon (p-Si), and a counter substrate provided with a common electrode disposed opposite to the TFT substrate at a predetermined interval; The liquid crystal layer is filled between the TFT substrate and the counter substrate.

In a TFT substrate, an Al-based material such as pure Al or Al alloy is used for wiring such as gate wiring and source-drain wiring. However, in recent years, due to circumstances such as an increase in the size of a liquid crystal display and a change in operating frequency from 60 kHz to 120 kHz, further reduction of the electrical resistance of the wiring has become an essential issue, and a wiring material exhibiting a smaller electrical resistance. The need for is increasing. Therefore, focusing on large panels for TV applications, Cu-based materials that have a lower electrical resistivity and superior hillock resistance than Al-based materials such as pure Al and Al alloys are attracting attention (metal (bulk materials)). ), The pure Al is 2.7 × 10 ⁻⁶ Ω · cm, whereas the pure Cu is as low as 1.8 × 10 ⁻⁶ Ω · cm.

  The applicant of the present application has also proposed a Cu alloy film capable of realizing a low resistance when directly connected to a transparent electrode film (pixel electrode) as Patent Document 1, for example.

  However, when a Cu-based material is applied to the wiring, there is a problem that adhesion with an insulating film or a semiconductor film (SiN film) is inferior to that of an Al-based material. The gate wiring of the liquid crystal display is formed on a glass substrate, and the source-drain wiring is formed on an insulating film. As an insulating film of a liquid crystal display, a SiN film is usually formed by a CVD method. However, since a Cu-based material has poor adhesion to the SiN film and the Cu-based wiring is easily peeled off from the SiN film, it can be used as a source-drain wiring. There is a problem that it cannot be used alone.

  In addition, a part of the source-drain wiring of the liquid crystal display is formed on a semiconductor film (a-Si (amorphous silicon) film or p-Si (polycrystalline silicon) film), and is ohmically connected to the source electrode or the drain electrode. Is planned. However, when the semiconductor film and the Cu-based wiring are directly bonded, Si and Cu are diffused at the bonding interface, so that the electrical resistivity at the interface increases and the contact resistance value increases. Therefore, it has been proposed to prevent mutual diffusion of Si and Cu by nitriding the surface of the semiconductor film to form an extremely thin nitride layer (SiN layer). In this case, as in the case of the insulating film, there is a problem that the adhesion between the SiN layer and the Cu wiring in the semiconductor film is low and the Cu wiring cannot be used alone as a source-drain wiring.

  Therefore, in order to improve the adhesion between the Cu-based wiring and the SiN film constituting the insulating film or the SiN layer in the semiconductor film (hereinafter sometimes referred to as "SiN film"), the Cu-based wiring and the SiN film are improved. In the meantime, a structure through a refractory metal layer (a Mo-containing layer such as a pure Mo layer or a Mo—Ti alloy layer) is employed. For example, in Patent Documents 2 and 3, a Cu melting point metal layer such as molybdenum (Mo) or chromium (Cr) is interposed between a Cu wiring and a semiconductor layer (a-Si layer) to form a Cu semiconductor layer. Techniques for suppressing the diffusion of

However, in order to form such a two-layer wiring of a Cu-based wiring and a refractory metal layer, a process for forming a refractory metal layer is further required, which increases the manufacturing cost of the display device. Furthermore, since different types of metals such as Cu and a refractory metal (Mo or the like) are laminated, corrosion may occur at the interface between Cu and the refractory metal during wet etching using a chemical solution. Also, there may be a difference in etching rate between these different metals. For example, when the etching rate of the lower layer in the two-layer structure is faster than that of the upper layer, an undercut in which the lower layer is constricted occurs, and the wiring cross section cannot be formed into a desired shape (for example, a shape having a taper angle of about 45 to 60 °). Problems can arise. Furthermore, since the electrical resistivity of refractory metals such as Cr and Mo is higher than that of Cu (Cr electrical resistivity: 12.9 × 10 ⁻⁶ Ω · cm, Mo electrical resistivity: 10.0 × 10 ^-6 Ω · cm), a two-layer wiring of a Cu-based wiring and a refractory metal layer has a problem of signal delay and power loss due to increased wiring electrical resistance.

JP 2007-17926 A JP-A-7-66423 JP-A-8-8498

  The present invention has been made in view of such circumstances, and the object thereof is to maintain low electrical resistance, which is a characteristic of Cu-based materials, and to have excellent adhesion with a SiN film and to undercoat during wet etching. Cu alloy film that can be satisfactorily etched without causing cut (hereinafter, such characteristics are sometimes referred to as “excellent wet etching”), and a high melting point metal such as the Mo-containing layer. To provide a flat panel display (display device) represented by, for example, a liquid crystal display device (liquid crystal display) used as a single layer TFT (particularly, source-drain wiring of TFT) without forming a layer. .

The Cu alloy film for a display device of the present invention that has solved the above problems is a Cu alloy film for a display device that is in direct contact with an insulating film and / or a semiconductor film, and the Cu alloy film constitutes the insulating film. A first layer in direct contact with the SiN layer in the SiN film and / or the semiconductor film, and a second layer formed on the first layer,
The first layer is
Containing 0.4 atomic% or more and less than 5.0 atomic% of nitrogen,
One or more elements (X element) selected from the group consisting of Ni, Al, Zn, Mn, and Fe are 0.1 atomic% or more and 0.5 atomic% or less (total if X element is composed of a plurality of elements) And / or the same); and / or
One or more elements (Z element) selected from the group consisting of Ge, Hf, Nb, Mo, and W are 0.1 atomic% or more and 0.3 atomic% or less (total when Z element is composed of a plurality of elements) The same, the same shall apply hereinafter);
And the thickness of the first layer is 2 nm or more and 100 nm or less.

The second layer is
One or more elements (X element) selected from the group consisting of Ni, Al, Zn, Mn, and Fe are 0.1 atomic% or more and 0.5 atomic% or less (total if X element is composed of a plurality of elements) And / or the same); and / or
One or more elements (Z element) selected from the group consisting of Ge, Hf, Nb, Mo, and W are 0.1 atomic% or more and 0.3 atomic% or less (total when Z element is composed of a plurality of elements) The same, the same shall apply hereinafter);
And the nitrogen content is preferably 0.01 atomic% or less (including 0 atomic%).

  The present invention also includes a display device characterized in that the Cu alloy film is used in a thin film transistor.

  As the display device, the Cu alloy film is used for a source electrode and / or a drain electrode of the thin film transistor and a signal line, and is in direct contact with the SiN layer in the SiN film and / or semiconductor film constituting the insulating film. If it is a thing, since the effect of this Cu alloy film is fully exhibited, it is preferable.

  In the Cu alloy film of the present invention, a Cu alloy having a specific component composition is selected, and the first layer that is in direct contact with the SiN film in the Cu alloy film is a layer containing a specific concentration of nitrogen. Even when the wiring film is made thick, it maintains excellent adhesion with the SiN film and has excellent etching characteristics (especially wet etching) ).

  As described above, since the Cu alloy film of the present invention is excellent in adhesion with the SiN film, it is insulated when applied to a source electrode and / or a drain electrode and a signal line of a display device (for example, a liquid crystal display). It can be directly deposited on a film or a semiconductor film, and can be used as a single layer without forming a refractory metal layer such as the Mo-containing layer. Therefore, the step of forming the refractory metal layer can be omitted, and a high-performance display device can be provided at low cost.

FIG. 1 is a graph showing the relationship between the nitrogen concentration in the sputtering gas (Ar + N ₂ ) and the nitrogen content in the first layer. FIG. 2 is a schematic cross-sectional view for explaining the amount of undercut measured in the examples.

  The inventors of the present invention have developed a Cu alloy film having excellent adhesion to the SiN film and excellent wet etching property while maintaining the low electrical resistance characteristic of the Cu-based material, and a display using the Cu alloy film. We conducted intensive research to realize the device.

  In particular, when examination was made to improve the adhesion between the Cu-based wiring and the SiN film, the Cu alloy film constituting the Cu-based wiring was placed on the first layer in direct contact with the SiN film and the first layer (in this case). "Upper" means that the second layer of the first layer is included, and the alloy component composition of the first layer and the amount of nitrogen to be contained are controlled. I found a good thing. Below, the 1st layer of Cu alloy film of this invention is explained in full detail first.

[About the alloy components in the first layer and their contents]
First, in order to improve the adhesion between the Cu-based wiring and the SiN film, the present inventors react Cu and SiN to such an extent that Cu and Si do not interdiffuse, and chemically bond (Cu and Si together). It was considered desirable to form a bond through N. The reason is that “chemical bond” has higher binding energy (bonding force) than “physical bond by physical adsorption”, so it is considered that stronger adhesion can be exhibited at the interface. is there.

  However, the affinity between Cu and N is smaller than the affinity between Si and N, and Cu and N do not form a chemical bond even when Cu and SiN are joined. Inferior to

  Then, when the alloy element which can improve the adhesiveness with a SiN film | membrane was examined, in this invention, Ni, Al, Zn, Mn, Fe, Ge, Hf, Nb, Mo, and W are made into Cu as an alloy element. It was found that it should be added. These alloy elements have strong affinity with nitrogen (it is easy to form nitrides) and have a diffusion coefficient equal to or higher than that of Cu, and are bonded via nitrogen (Si--) at the Cu / SiN interface. N—the alloying element) can be formed, and adhesion with the SiN film can be improved.

  In order to exert the above effect, at least one element (X element) selected from the group consisting of Ni, Al, Zn, Mn and Fe is 0.1 atomic% or more (preferably 0.15 atomic% or more). And / or one or more elements (Z element) selected from the group consisting of Ge, Hf, Nb, Mo and W are contained in an amount of 0.1 atomic% or more (preferably 0.15 atomic% or more).

  On the other hand, the greater the content of these elements, the better the adhesion with the SiN film, but the electrical resistivity increases. In the present invention, in order to improve the adhesion with the SiN film and to keep the electrical resistivity of the Cu alloy film low, in the case of the X element, 0.5 atomic% or less (preferably 0.3 atomic% or less) In the case of the above Z element, it is 0.3 atomic% or less (preferably 0.2 atomic% or less).

  Thus, the upper limit of the content is different between the X element and the Z element because the X element group (Ni, Al, Zn, Mn, Fe) and the Z element group (Ge, Hf, Nb, Mo, W) are Cu. This is because the electric resistance increase contribution rate when added to the slag is different.

  The X element is preferably one or more elements selected from the group consisting of Ni, Al, Zn, and Mn, and the Z element is preferably Ge and / or W.

[About nitrogen and its content in the first layer]
The first layer in the Cu alloy film of the present invention also contains nitrogen (N) in a range of 0.4 atomic% to less than 5.0 atomic%.

  By adding nitrogen, the crystal grain of the first layer can be made fine when formed by a sputtering method as will be described later. As a result, the stress applied to the interface with the SiN film can be reduced and effective. Adhesion can be improved. In order to exert such an effect, in the present invention, the first layer contains 0.4 atomic% or more of nitrogen. Preferably it is 1.0 atomic% or more.

However, even if the nitrogen content of the first layer is 5.0 atomic% or more, the crystal grain refinement effect is saturated. Further, the nitrogen contained in the first layer does not affect the electrical resistivity as much as the X element and the Z element, but when the nitrogen content is excessive, the electrical resistivity tends to increase. Further, when the nitrogen content is increased, undercut is likely to occur during wet etching. In order to increase the nitrogen content of the first layer to 5.0 atomic% or higher, it is necessary to perform sputtering using a gas having a nitrogen concentration in the sputtering gas (Ar + N ₂ ) of 40 volume% or higher during film formation. However, the increase in the nitrogen content of the sputtering gas relatively decreases the amount of Ar in the sputtering gas, lowers the sputtering yield, and decreases the productivity of the Cu alloy film. Therefore, the nitrogen content of the first layer is less than 5.0 atomic%. Preferably it is 3.0 atomic% or less, More preferably, it is less than 2.5 atomic%.

  The balance other than the above components in the first layer is Cu and inevitable impurities.

[About the second layer]
Next, the second layer of the Cu alloy film of the present invention will be described. The present invention does not strictly limit the component composition of the second layer, but from the viewpoint of realizing a low electrical resistance wiring and from the viewpoint of simply forming a film in a series of manufacturing steps, It is preferable that one layer and components other than nitrogen are made of the same Cu alloy. Further, it is preferable to make the alloy composition the same as that of the first layer in this way, because it is possible to prevent the occurrence of undercut due to the difference in etching rate between the first layer and the second layer, and to etch well.

For the above reasons, the component composition of the second layer is
One or more elements (X element) selected from the group consisting of Ni, Al, Zn, Mn and Fe are 0.1 atomic% or more (more preferably 0.15 atomic% or more) 0.5 atomic% or less (More preferably 0.3 atomic% or less); and / or
One or more elements (Z element) selected from the group consisting of Ge, Hf, Nb, Mo and W are 0.1 atomic% or more (more preferably 0.15 atomic% or more) 0.3 atomic% or less (More preferably 0.2 atomic% or less);
It is preferable that it contains.

  The X element is preferably one or more elements selected from the group consisting of Ni, Al, Zn, and Mn, and the Z element is preferably Ge and / or W.

  The second layer does not actively contain nitrogen like the first layer, and even if it is contained, the inevitable impurity level is 0.01 atomic% or less (including 0 atomic%). The remainder of the second layer other than the above components is Cu and inevitable impurities.

[About the film thickness of the first layer and the second layer]
The film thickness of the first layer is 2 nm or more and 100 nm or less. If the thickness of the first layer is less than 2 nm, the effect of reducing the interfacial stress with the SiN film due to the refinement of crystal grains is insufficient, and sufficient adhesion with the SiN film cannot be ensured. The film thickness of the first layer is preferably 5 nm or more.

  On the other hand, if the film thickness of the first layer is more than 100 nm, it is difficult to control the wiring cross section to a desirable tapered shape. The layer to which nitrogen is added (first layer) has a higher etching rate than the layer to which nitrogen is not actively added (second layer). Undercut is likely to occur at the bottom (first layer portion) of the Cu alloy film, and the Cu alloy film cannot be patterned into a desired tapered shape. In addition, when the thickness of the first layer is thick, the effective electrical resistivity increases. Therefore, the film thickness of the first layer is 100 nm or less. Preferably it is 50 nm or less.

  The film thickness of the second layer is preferably 100 nm or more from the viewpoint of reducing the effective electrical resistivity. More preferably, it is 200 nm or more.

The first layer may be a composition gradient layer that satisfies the above component composition and has a depth direction concentration profile in which the nitrogen content decreases from the substrate side toward the second layer side. Such a composition gradient layer is formed, for example, by gradually switching the sputtering gas from (Ar + N ₂ ) to pure Ar while the sputtering target is sputtered when the first layer is formed by the sputtering method described later. be able to.

[Method for Forming Cu Alloy Film of the Present Invention]
It is desirable to employ a sputtering method for forming the Cu alloy film. Sputtering is a method in which an inert gas such as Ar is introduced into a vacuum, a plasma discharge is formed between a substrate and a sputtering target (hereinafter sometimes referred to as a target), and Ar or the like ionized by the plasma discharge is formed. This is a method of making a thin film by colliding with the target and knocking out atoms of the target and depositing them on a substrate.

In order to form the first layer having a nitrogen content of 0.4 atomic% or more and less than 5.0 atomic% by the above sputtering method, a sputtering gas having a nitrogen concentration of 5 volume% or more and less than 40 volume% shown below ( It is desirable to perform sputtering using Ar + N ₂ ) (details will be shown in the examples described later). By forming using the sputtering gas, the crystal grains of the first layer are made finer, the stress applied to the interface with the SiN film can be reduced, and effective adhesion can be improved.

For sputtering, a Cu alloy sputtering target having substantially the same alloy composition as the desired first layer or second layer is used, and for the formation of the first layer, the above-mentioned nitrogen concentration sputtering gas (Ar + N ₂ ) is used. The second layer may be formed by using only Ar gas. In addition, although Ar was mentioned as a representative example as a gas constituting the sputtering gas used at the time of film formation, other rare gases such as Xe can be used instead of Ar.

  The composition of the sputtering target and the composition of the Cu alloy film (Cu alloy wiring) formed by the sputtering method may be slightly different. However, the “deviation” of the composition is approximately several percent or less of the alloy concentration, and the alloy composition (alloy concentration) of the sputtering target is within ± 10% of the alloy composition (alloy concentration) of the desired Cu alloy film (for example, When the amount of X element is 0.5 atomic%, it is possible to form a Cu alloy film (first layer and second layer) having a predetermined composition by controlling to 0.5 ± 0.05 atomic%) it can.

  The Cu alloy film of the present invention is preferably used for a source electrode and / or a drain electrode and a signal line in a TFT of a display device. In particular, a Cu alloy film is used for the source electrode and / or drain electrode and signal line of the TFT, and the first layer constituting the Cu alloy film is an SiN film and / or a SiN layer in the semiconductor film constituting the insulating film. The effect of the present invention is sufficiently exerted when it is in direct contact.

  The Cu alloy film of the present invention can also be used as a gate electrode and a scanning line. In this case, all of the Cu alloy wirings of the TFT can have the same component composition.

  The present invention is characterized in that the structure / component composition of the Cu alloy film is specified, and the requirements for configuring the TFT substrate and the display device other than the Cu alloy film are not particularly limited as long as they are normally used. Examples of the transparent pixel electrode (transparent conductive film) used in the present invention include an indium tin oxide (ITO) film and an indium zinc oxide (IZO) film.

  The Cu alloy film may be subjected to a heat treatment after the film formation. As conditions for this heat treatment, for example, temperature: 270 to 450 ° C., holding time: 5 to 120 minutes can be mentioned. Further, the thermal history after the Cu alloy film is formed (for example, a step of forming a SiN film) may satisfy the temperature and time.

  In manufacturing the display device provided with the Cu alloy film of the present invention, a general process of the display device may be employed. For example, the manufacturing method described in Patent Document 1 may be referred to.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.

(Sample preparation)
A SiN film was formed to a thickness of 200 nm on a glass substrate (Corning Eagle 2000, diameter 100 mm × thickness 0.7 mm), and a DC magnetron sputtering method (first layer and second layer) was further formed on the SiN film. The film formation conditions other than the sputtering gas of the layer are as follows, and the first layer so as to have the film thicknesses shown in Tables 1 and 2 (the total film thickness of the first layer and the second layer is 500 nm), Films were formed in the order of the second layer. As a comparative example, a pure Cu film (single layer) was also formed under the same conditions. Then, after the film formation, a heat treatment was performed for 30 minutes at 350 ° C. in a vacuum atmosphere to obtain a sample (wiring film).

  Note that pure Cu was used as a sputtering target for the formation of the pure Cu film. Moreover, the target which installed the chip | tip containing alloy elements other than Cu on the pure Cu sputtering target was used for formation of Cu alloy film of various alloy components.

(Deposition conditions)
・ Back pressure: 1.0 × 10 ⁻⁶ Torr or less ・ Ar gas pressure: 2.0 × 10 ⁻³ Torr
Ar gas flow rate: 30sccm
Sputtering power: 3.2 W / cm ²
・ Distance between electrodes: 50mm
・ Substrate temperature: Room temperature

Pure Ar was used for forming the second layer as the sputtering gas used during film formation. In addition, a mixed gas of Ar and N ₂ was used for forming the first layer. In the control of the nitrogen content of the first layer, the mixing ratio of the Ar and N ₂ in the sputtering gas is set at a partial pressure of Ar and N _2, the flow rate ratio of the partial pressure ratio of Ar and N ₂ is Ar and N ₂ Set in.

  The following measurements were performed on the samples obtained as described above.

(1) Component analysis of Cu alloy film The nitrogen content in the first layer was prepared by separately preparing a sample in which only the first layer was formed by the above method, and the nitrogen content in the first layer of this sample was It was determined by quantitative analysis by “Indophenol spectrophotometry”.

Further, the relationship between the nitrogen concentration in the used sputtering gas (Ar + N ₂ ) and the nitrogen content in the first layer was examined. The result is shown in FIG. From FIG. 1, in order to make the nitrogen content in the first layer 0.4 atomic% or more and less than 5.0 atomic%, the nitrogen concentration in the sputtering gas (Ar + N ₂ ) is 5 volume% or more and less than 40 volume%. You can see that.

  Components other than nitrogen in the first layer and components in the second layer were confirmed by quantitative analysis using an ICP emission spectrometer (ICP emission spectrometer “ICP-8000 type” manufactured by Shimadzu Corporation).

  As described above, the second layer is not formed using a sputtering gas containing nitrogen, and the nitrogen content in the second layer is an inevitable impurity level (0.01 atomic% or less).

(2) Evaluation of Adhesiveness with SiN Film In order to evaluate the adhesiveness between the wiring film and the SiN film, a peeling test using the following tape was performed.

  A grid-like cut was made at intervals of 1 mm using a cutter knife on the film formation surfaces of the sample subjected to the heat treatment and the sample immediately after sputtering (as-deposited state, as-depo.). Next, a 3M black polyester tape (Product No. 8422B) was firmly attached onto the film formation surface, and the tape was peeled off at once while holding the tape at a peeling angle of 60 °. The number of sections of the grids peeled by the tape was counted, and the ratio (peeling rate) to all the sections was obtained. This evaluation shows that the smaller the peel rate, the better the adhesion. In the present invention, the case where the peel rate was less than 20% was evaluated as ◯ (excellent in adhesion), and the case where the peel rate was 20% or more was evaluated as x (inferior in adhesiveness). The results are shown in Tables 1 and 2.

(3) Measurement of electrical resistivity The sample (wiring film) subjected to the above heat treatment is subjected to photolithography and wet etching, and processed into a stripe pattern (pattern for measuring electrical resistivity) having a width of 100 μm and a length of 10 mm. Then, the electrical resistivity of the pattern was measured at room temperature by a direct current four-probe method using a prober. And the case where the electrical resistivity after the said heat processing is less than 4.0 microhm * cm was evaluated as (circle), and the case where it is 4.0 microhm * cm or more was evaluated as x. The results are shown in Tables 1 and 2.

(4) Evaluation of wet etching property The sample (wiring film) subjected to the above heat treatment was subjected to photolithography to form a stripe pattern having a line and space of 10 μm width, and phosphoric acid: nitric acid: water = 75: Etching was performed using a 5:20 mixed acid etchant. Then, the wiring film cross section of the etched sample is observed with an SEM, the undercut amount (undercut depth) shown in FIG. 2 is measured, and when the undercut amount is less than 1.0 μm, there is no undercut. The case of 1.0 μm or more was evaluated as x with undercut. The results are shown in Tables 1 and 2.

  From Table 1 and Table 2, it can be considered as follows. No. in Table 1 and Table 2 Since the Cu alloy films of 6, 7, 10, 11, and 17 to 31 satisfy the requirements defined in the present invention, they exhibit excellent adhesion to the SiN film, low electrical resistivity, and wet etching properties. It turns out that it is also excellent.

  In contrast, no. Since 1 is a single layer of a pure Cu film, the adhesion with the SiN film is poor.

  No. Reference numerals 2 to 4 are films having a laminated structure, but the first layer does not contain a prescribed X element or Z element, so that the adhesion with the SiN film is poor. No. No. 4 seems to have caused an undercut during wet etching because of its high nitrogen content.

  No. In No. 5, the first layer contained X element (Ni), but its content was insufficient, so that the adhesion with the SiN film was inferior.

  No. In No. 8, the first layer contained X element (Ni), but the electric resistivity was high because the content was excessive.

  No. No. 9 was inferior in adhesion to the SiN film because the first layer was too thin.

  No. In No. 12, the electrical resistivity increased because the film thickness of the first layer was too thick. No. In No. 12, the first layer is thick, but the nitrogen content is small, so it seems that no significant undercutting occurred.

  No. Nos. 13 to 15 were inferior in adhesion to the SiN film because the nitrogen content of the first layer was small.

  No. No. 16 has a relatively high nitrogen content in the first layer, and thus has a high electrical resistivity and undercuts.

  No. No. 32 was unable to improve the adhesion with the SiN film because the alloy element (Bi) contained in the wiring film was an element that was not specified in the present invention.

Claims (4)

A Cu alloy film for a display device that is in direct contact with at least one of an SiN film constituting an insulating film and an SiN layer formed on the surface of a semiconductor film (hereinafter collectively referred to as “SiN film / layer”) , The Cu alloy film includes a first layer in direct contact with the SiN film / layer and a second layer formed on the first layer,
The first layer is
Containing 0.4 atomic% or more and less than 2.5 atomic% of nitrogen,
One or more elements (X element) selected from the group consisting of Ni, Al, Zn, Mn and Fe are 0.1 atomic% or more and 0.5 atomic% or less, and / or
A film of the first layer containing one or more elements selected from the group consisting of Ge, Hf, Nb, Mo, and W (Z element) in a range of 0.1 atomic% to 0.3 atomic%. A Cu alloy film for a display device, wherein the thickness is 2 nm or more and 100 nm or less. The second layer is
One or more elements (X element) selected from the group consisting of Ni, Al, Zn, Mn and Fe are 0.1 atomic% or more and 0.5 atomic% or less, and / or
Containing at least one element selected from the group consisting of Ge, Hf, Nb, Mo and W (element Z) in a range of 0.1 atomic% to 0.3 atomic% and a nitrogen content of 0.01 atomic% The Cu alloy film for a display device according to claim 1, which is the following (including 0 atomic%).   3. A display device, wherein the Cu alloy film for a display device according to claim 1 is used for a thin film transistor.   The display device according to claim 3, wherein the Cu alloy film for a display device according to claim 1 or 2 is used for a source electrode and / or a drain electrode and a signal line of the thin film transistor.

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