JP4463075B2 - Transflective liquid crystal display device, method for producing transflective liquid crystal display device, TFT substrate, and method for producing TFT substrate - Google Patents

Description

  The present invention relates to an active matrix type display device used as a display device for image and character information of OA equipment, etc., a transflective liquid crystal display device having a transmissive region and a reflective region in a pixel region, a manufacturing method thereof, and a semi The present invention relates to a transmissive liquid crystal display device, a reflective liquid crystal display device in which a pixel region is formed of a reflective material, a TFT substrate used in an electroluminescent (electroluminescence; EL, etc.) display device, and a manufacturing method of the TFT substrate.

A pixel region of a TFT (thin film transistor) substrate used in a general transflective liquid crystal display device has a transmission region for transmitting backlight light and a reflection region for reflecting ambient light incident on the liquid crystal layer. Provided.
The pixel region of the TFT substrate used in the reflective liquid crystal display device is formed of a reflective material, and the liquid crystal panel switches between transmitting and blocking the reflected light instead of the backlight light. Furthermore, in recent years, an electroluminescent display device in which a pixel region of a TFT substrate is formed of a light emitter such as an EL and a reflective material has been used as an electro-optical element instead of backlight.

In a TFT substrate used in such a transflective liquid crystal display device, a reflective liquid crystal display device, and an electroluminescent display device, an indium oxide thin film (Indium Thin Oxide) is hereinafter referred to as ITO. ) A pixel region is formed by patterning a film and an Al film having excellent reflection characteristics on the ITO film.
In addition, in order to apply a voltage to the TFT, the terminal portion of the gate wiring and the source wiring formed outside the display area of the display device is formed so as to be covered with the ITO film, thereby preventing the gate wiring and the source wiring from being oxidized and driving The connection with the driver IC terminal which is a circuit for use is made favorable.

  The Al film is patterned by photolithography using a developer, but pinholes are generated when the Al film is formed. Further, when Al elutes in the developer used for development, pinholes are generated in the Al film. At this time, when the developing solution reaches the ITO film through the pinhole generated in the Al film, an electrolytic corrosion reaction occurs and the ITO in the pixel region and the terminal portion is corroded (reduced).

  In order to solve this problem, the liquid crystal display device described in Patent Document 1 below prevents Al from eluting into the developer by sequentially laminating Cr, Al, and Cr on ITO.

  Further, in the method for manufacturing a semiconductor device described in Patent Document 2 below, by forming a Ni film and an Al film on the ITO film, and maintaining the Al potential in the developer at a potential higher than the corrosion potential of ITO, Corrosion of ITO, which occurs when pinholes reaching the ITO film exist in the Al film or Ni film, is prevented.

JP2003-50389A (pages 8-10 and 8-10) JP-A-5-242744 (page 2-4, Fig. 1-4)

  However, in the manufacturing method of the TFT substrate described in Patent Document 1, Al and Cr cannot be etched with the same etching solution, so two etchings are required. Further, when the reflection region is formed of Cr, the reflection characteristic is low, so that it is necessary to finally remove it, and there is a problem that the manufacturing process becomes very complicated.

  Further, in the semiconductor device described in Patent Document 2, since the Al film is formed on the surface in contact with the developer, Al is likely to elute into the developer. Furthermore, since the Ni film is formed below the Al film, the effect of the Ni film that maintains the developer in which Al is dissolved at a potential higher than the corrosion potential of ITO cannot be sufficiently obtained, and the corrosion of ITO is completely prevented. It cannot be prevented. Further, since Al is patterned by dry etching and Ni film is patterned by wet etching twice, there is a problem that the manufacturing process becomes complicated.

The present invention has been made to solve the above-described problems, and prevents the corrosion of ITO due to the dissolution of Al into the developer, and the transflective liquid crystal display device capable of simplifying the manufacturing process and the manufacturing thereof. It aims to provide a method.
Another object of the present invention is to provide a TFT substrate used in a transflective liquid crystal display device, a reflective liquid crystal display device, and an electroluminescent display device, and a method for manufacturing the TFT substrate.
Further, the present invention provides a TFT substrate and a TFT substrate manufacturing method used in an electroluminescent display device, and a TFT substrate capable of increasing luminous efficiency by increasing supply efficiency of hole carriers injected into an organic electroluminescent layer, and It aims at proposing the manufacturing method of a TFT substrate.

The transflective liquid crystal display device according to the present invention is a semi-transparent liquid crystal display device that includes a transmissive region that transmits backlight light and a reflective region that reflects ambient light incident from the outside, together with a liquid crystal driving element, on an insulating substrate. In the transmissive liquid crystal display device, the reflective region includes a reflective film provided on and bonded to the transparent conductive film that forms the transmissive region, and the reflective film includes a group 8 element Ni, It is formed of an Al alloy containing at least one of Fe, Pd, Pt, Rh, Ru, and Co.

A method of manufacturing a transflective liquid crystal display device according to the present invention includes a transmissive region that transmits backlight light and a reflective region that reflects ambient light incident from the outside together with a liquid crystal driving element on an insulating substrate. A method of manufacturing a transflective liquid crystal display device, comprising: joining a transparent conductive film to at least one of group 8 elements Ni, Fe, Pd, Pt, Rh, Ru, and Co reflecting film is formed of Al alloy containing, before Symbol forming a mask pattern corresponding to the transmissive region to the reflective film, etching the reflective film through the mask pattern, the reflective film is etched The transmissive region is formed in a portion, and the reflective region is formed in a portion where the reflective film remains .

The TFT substrate according to the present invention is a TFT substrate configured by arranging a transmission region for transmitting backlight light and a reflection region for reflecting ambient light incident from the outside together with a liquid crystal driving element on an insulating substrate. The reflective region has a reflective film provided on and joined to the transparent conductive film that forms the transmissive region, and the reflective film is composed of Ni, Fe, Pd, Pt, Rh, which are group 8 elements. , Ru, Co, and an Al alloy containing at least one of them.

Another TFT substrate according to the present invention includes a pixel region that reflects ambient light incident from the outside, a liquid crystal driving element, a terminal group that is covered with a transparent conductive film and applies a display signal and a voltage to the liquid crystal driving element. The pixel region includes at least one of Ni, Fe, Pd, Pt, Rh, Ru, and Co as group 8 elements. It is formed of an Al alloy.

The TFT substrate manufacturing method of the present invention also includes a TFT configured by disposing a transmissive region that transmits backlight light and a reflective region that reflects ambient light incident from the outside together with a liquid crystal driving element on an insulating substrate. A method for manufacturing a substrate, comprising: an Al alloy comprising at least one of Ni, Fe, Pd, Pt, Rh, Ru, and Co, which are group 8 elements, bonded to a transparent conductive film; forming a film, a mask pattern corresponding to the transmissive area before Symbol reflective film, etching the reflective film through the mask pattern, the transmission region to the portion where the reflective film is etched And forming the reflective region in a portion where the reflective film remains .

That by the present invention a semi-transmissive liquid crystal display device, the reflective region has a reflective film provided by bonding it on the transparent conductive film forming the transmissive region, the reflective film is a Group 8 elements Since an Al alloy containing at least one of Ni, Fe, Pd, Pt, Rh, Ru, and Co is formed, the potential of the Al alloy in the developer is maintained at a potential higher than the corrosion potential of ITO. Even if the liquid reaches the ITO film, the ITO film does not corrode.

Method of manufacturing a transflective liquid crystal display device according to the present invention, Ni is a Group 8 elements, Fe, Pd, Pt, Rh , Ru, transparent conductive reflective film made of Al alloy containing at least any one of Co The reflective film is formed on the film by bonding to it, and the reflective film is etched through the mask pattern on the reflective film. The transmissive region is formed in the etched portion of the reflective film, and the reflective film remains in the remaining portion. Since the reflective region is formed, the process of forming the transmissive region can be simplified.

In addition, the TFT substrate according to the present invention has a reflective film provided on and bonded to a transparent conductive film forming a transmissive region, and this reflective film is composed of Ni, Fe, Pd, Pt, Rh, which are group 8 elements. , Ru, and Co are formed of an Al alloy containing at least one of them, so that the ITO film does not corrode.
The T FT substrate that by the present invention, picture element areas, Ni is Group 8 elements, Fe, Pd, Pt, Rh, Ru, since it is made of Al alloy containing at least any one of Co The potential of the Al alloy in the developer is maintained at a potential higher than the corrosion potential of ITO, and even if the developer reaches the ITO film, the ITO film does not corrode.

The TFT substrate manufacturing method according to the present invention is an Al alloy containing at least one of Ni, Fe, Pd, Pt, Rh, Ru, and Co, which are group 8 elements, bonded to a transparent conductive film. forming a composed reflective film from said forming a mask pattern corresponding to the transmissive region on the reflective layer, etching the reflective film through the mask pattern, the a portion where the reflective film is etched Since the process includes forming a transmissive region and forming the reflective region in a portion where the reflective film remains, the process of forming the transmissive region can be simplified.

  Hereinafter, the transflective liquid crystal display device and manufacturing method of the present invention, the TFT substrate used in the transflective liquid crystal display device and the manufacturing method thereof, the reflective liquid crystal display device, and the TFT substrate used in the electroluminescent display device and An embodiment of the manufacturing method will be described with reference to the drawings. In addition, in each figure, the same code | symbol is abbreviate | omitted description as the same or substantially the same structure.

Embodiment 1.
First, a TFT substrate used in the transflective liquid crystal display device according to Embodiment 1 of the present invention and a method for manufacturing the TFT substrate will be described in detail. FIG. 1 is a plan view showing a schematic configuration when a TFT substrate used in the first embodiment is completed. In FIG. 1, each of the plurality of pixel regions G1 provided on the TFT substrate includes a transmission region T that transmits light and a reflection region S that reflects ambient light incident on the liquid crystal layer (shown by hatching in the drawing). Part).

FIG. 2 is a cross-sectional view of the TFT substrate shown in FIG. In FIG. 2, 1 is an insulating substrate, 2 is a gate electrode, 3 is an auxiliary capacitance electrode for holding a voltage in the liquid crystal layer, and a first insulating film 4 is provided on the upper layer. A semiconductor film 5 and an ohmic contact film 6 are provided on the gate electrode 2 via the first insulating film 4. Reference numeral 7 denotes a source electrode, and 8 denotes a drain electrode, and the liquid crystal driving element 21 is formed by the above-described members. A second insulating film 9 and an interlayer insulating film 10 are formed thereon. Reference numeral 13 denotes an ITO film that forms the transmission region T, and a reflective film 14 (shaded portion in the figure) bonded to the ITO film 13 and a metal film 15 bonded to the reflective film 14 are laminated on the reflective film 14. Then, the reflection region S is formed.

  Next, the manufacturing method of the TFT substrate shown in FIG. 2 will be described in detail with reference to FIG. FIG. 3 is a cross-sectional view for explaining a manufacturing method of the TFT substrate 20 constituting the transflective liquid crystal display device according to the present invention.

  Hereinafter, an embodiment of a method for manufacturing the TFT substrate 20 will be described with reference to FIGS. In FIG. 3 (a), Cr or the like is formed as a first metal thin film on the insulating substrate 1 by a sputtering method to a thickness of 2000 mm, and the gate electrode 2 and the auxiliary capacitance electrode 3 are formed by a photolithography process. To do. Next, 4000 nm of SiN is deposited as the first insulating film 4 by CVD, 1500 nm of a-Si is deposited as the semiconductor film 5, and 300 mm of n + -a-Si is deposited as the ohmic contact film 6. The semiconductor film 5 and the ohmic contact film 6 are formed by a plate making process.

  Next, Cr or the like is formed as the second metal thin film to a thickness of 2000 mm using a sputtering method to form the source electrode 7 and the drain electrode 8. Next, the second insulating film 9 is formed by depositing SiN with a thickness of 1000 mm using the CVD method. Subsequently, JSR PC335 is applied and formed as an interlayer insulating film 10 using a spin coating method so as to have a film thickness of 3.2 to 3.9 μm, and the transmissive region pattern 11 and the contact hole are formed using a photolithography process. Twelve patterns are formed.

  Next, as shown in FIG. 3A, ITO is formed as a transparent conductive film with a thickness of 1000 mm using a sputtering method, and etched using a solution containing hydrochloric acid and nitric acid by a photolithography process. To form the ITO film 13.

  Next, as shown in FIG. 3B, a reflective film 14 containing at least Al is formed to a thickness of 3000 mm using a sputtering method, and subsequently, Ni, Fe, Pd, Pt, Rh, Re, Ru A metal film 15 containing at least one of Co, In, Nb, V, Mo, W, and Zr is formed to a thickness of 20 to 200 mm. The metal film 15 is made of, for example, Ni alone. The metal film 15 is made of any one of Ni, Fe, Pd, Pt, Rh, Re, Ru, Co, In, Nb, V, Mo, W, and Zr, or some of them are alloyed. Configured as

  Next, as shown in FIG. 3C, a photoresist film 16 is applied and formed, and exposure is performed using a mask (not shown) having a pattern corresponding to the predetermined transmission region T.

  Next, as shown in FIG. 3D, an opening P is formed in the photoresist film 16 using an organic alkaline photoresist developer.

Next, as shown in FIG. 3E, etching is performed to remove the reflective film 14 and the metal film 15 at the same time using a solution containing phosphoric acid, nitric acid, and acetic acid, thereby forming a transmissive region T and a reflective region S. . The transmission region T is formed in a portion where the reflection film 14 and the metal film 15 are etched, and the reflection region S is formed in a portion where the reflection film 14 and the metal film 15 remain.

  As described above, when the photoresist film 16 is formed on the reflective film 14 and the development process is performed, when an organic alkaline photoresist developer is used, Al is eluted into the developer. When the developer reaches the ITO film 13 from a pinhole or the like of the reflective film 14, the ITO film 13 is reduced and corroded by an electrolytic corrosion reaction.

  Here, corrosion of ITO occurs when the corrosion potential becomes −1.3 V or less. The potential when Al is immersed in the developer alone is -1.93 V, and in the developer from which Al is eluted, the ITO film 13 is pulled down to a potential lower than the corrosion potential, so that the ITO film 13 is corroded. . Therefore, in order to prevent corrosion of the ITO film 13, it is necessary to maintain the potential of the ITO film 13 at a potential higher than −1.3V.

  On the other hand, for example, the potential when Ni is immersed in the developer is 0.8 V, which is higher (noble) than the corrosion potential of the ITO film 13. Further, the potential when Fe, Pd, Pt, Rh, Re, Ru, Co, In, Nb, V, Mo, W, and Zr are immersed in the developer is also −0.9 to +0.1, and ITO It is higher than the corrosion potential of the film. Note that the potential of Pt in the developer is +0.1 V, the potential of Pd is -0.2 V, and the potential of Co is -0.8 V.

  It should be noted that the potential in the developer is an organic alkali developer, a solution having a tetramethylammonium hydroxide concentration of 2.38% (PH value of 11 to 12) is set at 23 ° C., and the reference electrode is This is the potential when saturated silver or silver chloride is used.

  In the present invention, since the metal film 15 that raises the potential of Al in the developer is formed on the upper layer of the reflective film 14, even when Al is eluted, the potential of the developer is maintained at a potential higher than the corrosion potential of ITO. The Thereby, even if the developer reaches the ITO film 13, the ITO film 13 is not corroded.

  Since Ni or the like has a reflectance lower than that of Al and has a slower etching rate, it is desirable to form the metal film 15 with a thickness of 200 mm or less in order to perform batch etching. If the metal film 15 is formed with a thickness of 20 mm or more, it can be controlled to a uniform thickness. Therefore, it is desirable to form the metal film 15 with a film thickness of 20 to 200 mm.

  In the above embodiment, the metal film 15 is formed on the reflective film 14, but the metal film 15 is made of Ni, Fe, Pd, Pt, Rh, Re, Ru, Co, In, Nb, V, Mo, W, You may form with a film thickness of 20 to 1000 mm using an Al alloy containing at least one of Zr. For example, an Al alloy containing 5 at% of Ni as an additive element is formed on the reflective film 14 with a thickness of 500 mm. Since such an Al alloy contains Al as a main component, the reflectance is not impaired, and the potential of Al in the developer can be maintained higher than the corrosion potential of ITO. Further, the etching rate can be made close to Al, and the cross-sectional shape of etching can be made smooth.

  In the case where the potential of the Al alloy in the developer is -1.4 V to -1.1 V, the composition ratio at% of the additive element added to Al will be described. It is appropriate that Ni is 1 to 10 at% for the Al—Ni alloy, Pt is 0.5 to 10 at% for the Al—Pt alloy, and Pd is 5 to 15 at% for the Al—Pd alloy. When adding Co, Ru or Rh as additive elements to Al, the composition ratio of these additive elements is suitably 5 to 15%. Also, the composition of Nb is 8 to 15 at% for the Al-Nb alloy, Mo is 10 to 22 at% for the Al-Mo alloy, W is 8 to 15 at% for the Al-W alloy, and Zr is 8 to 15 at% for the Al-Zr alloy. The ratio is appropriate. Even if the potential in the developer is -1.4 V, the corrosion reaction rate of ITO is slowed and there is no problem in the actual process. Therefore, the potential in the Al alloy developer is -1.4 V to- Assuming the case of 1.1 V, an appropriate composition ratio was shown.

  In addition, when the metal film 15 containing at least one of Ni, Fe, Pd, Pt, Rh, Ru, and Co, which are group 8 elements, is formed, the potential of Al in the developer is set higher than the corrosion potential of ITO. Since the metal film 15 can be formed thin without causing a corrosion reaction of the ITO film 13, the reflection characteristics of the Al film are not impaired.

  The reflective film 14 may be an Al alloy containing at least one of Ni, Fe, Pd, Pt, Rh, Re, Ru, Co, In, Nb, V, Mo, W, and Zr. As a result, the etching rates of the reflective film 14 and the metal film 15 can be made closer, and the cross-sectional shape of the etching can be made smooth.

  The reflective film 14 may be an Al alloy containing at least one of Cu, Si, Nd, Y, and Hf. As a result, the crystal grain growth is suppressed as compared with the case where the reflective film 14 is formed of only Al, so that surface irregularities are reduced. For this reason, since the surface of the reflective film 14 is a dense flat surface, the reflectance of the reflective film 14 is increased by suppressing light scattering.

  In this case, as the metal film 15, a metal containing at least one of Ni, Fe, Pd, Pt, Rh, Ru, Re, In, Nb, V, Mo, W, Zr, and Co is used. desirable.

  The metal film 15 may be an Al alloy containing at least one of Ni, Fe, Pd, Pt, Rh, Ru, Re, In, Nb, V, Mo, W, Zr, and Co.

  The reflective film 14 includes at least one of Ni, Fe, Pd, Pt, Rh, Ru, and Co, which are group 8 elements capable of maintaining a high potential of Al in the developer. An Al alloy may be used. In this case, it is appropriate that the composition ratio of Al to the additive element is the same as that in the case where the metal film 15 is made of an Al alloy of Al and the additive element. When the reflective film 14 is formed of the above Al alloy, the metal film 15 may be omitted. Thereby, while preventing the corrosion reaction of ITO, the manufacturing process of the TFT substrate constituting the transflective liquid crystal display device can be reduced.

  Further, a second metal film containing at least one of Cr, Ti, Ta, and Mo may be formed below the reflective film 14 with a thickness of 50 to 1000 mm (not shown). By forming in this way, the electrical contact resistance value between the reflective film 14 and the ITO film 13 can be lowered and the coverage to the base is improved. Thereby, lighting display defects of the pixels can be prevented. In particular, when Mo is used, it is possible to perform etching in which the reflective film 14, the metal film 15, and the second metal film are simultaneously removed with an Al etching solution.

Embodiment 2.
FIG. 4 is a plan view showing a schematic configuration when a TFT substrate used in the reflective liquid crystal display device according to the second embodiment is completed. In FIG. 4, each of the plurality of pixel regions G2 provided on the TFT substrate is formed by a reflection region S that reflects the ambient light incident on the liquid crystal layer.

  FIG. 5 shows a cross-sectional view of a terminal portion for applying a display signal and a voltage to the liquid crystal driving element, and a cross-sectional view of the TFT substrate shown in FIG.

  In FIG. 5, a TFT substrate 40 has terminal portions of a plurality of gate lines (not shown) and source lines (not shown) formed outside the display area of the display device in order to apply a voltage to the liquid crystal drive element 21. A plurality of gate terminals 35 and source terminals 34 are provided. Reference numerals 37 and 38 denote ITO films provided on the upper layers of the source terminal 34 and the gate terminal 35, respectively, and the reflective film 14 and the metal film 15 are laminated in each pixel region G2. Other configurations are the same as those of the first embodiment.

  Next, a manufacturing method of the TFT substrate 40 will be described in detail with reference to FIG. FIG. 6 is a cross-sectional view for explaining a manufacturing method of the TFT substrate 40 used in the reflective liquid crystal display device according to the second embodiment.

  Hereinafter, an embodiment of a method for manufacturing the TFT substrate 40 will be described with reference to FIGS. In FIG. 6A, Cr or the like is formed as a first metal thin film on the insulating substrate 1 to a thickness of 2000 mm using a sputtering method, and the gate electrode 2, the auxiliary capacitance electrode 3, and the gate are formed by a photolithography process. Terminal 35 is formed. Next, 4000 nm of SiN is deposited as the first insulating film 4 by CVD, 1500 nm of a-Si is deposited as the semiconductor film 5, and 300 mm of n + -a-Si is deposited as the ohmic contact film 6. The semiconductor film 5 and the ohmic contact film 6 are formed by a plate making process.

  Next, as the second metal thin film, Cr or the like is formed to a thickness of 2000 mm using a sputtering method, and the source terminal 34, the source electrode 7 and the drain electrode 8 are formed. Next, the second insulating film 9 is formed by depositing SiN with a thickness of 1000 mm using the CVD method. Subsequently, JSR PC335 is applied and formed as an interlayer insulating film 10 using a spin coating method so as to have a film thickness of 3.2 to 3.9 μm, and a contact hole is formed on the source terminal 34 using a photolithography process. 22, a contact hole 23 is formed on the gate terminal 35, and a contact hole 30 is formed on the drain electrode 8.

  Next, as shown in FIG. 6A, ITO is formed as a transparent conductive film with a thickness of 1000 mm using a sputtering method, and etched using a solution containing hydrochloric acid and nitric acid by a photolithography process. Then, an ITO film 37 is formed on the source terminal 34 and an ITO film 38 is formed on the gate terminal 35.

  Next, as shown in FIG. 6B, a reflective film 14 containing at least Al is formed by sputtering to a thickness of 3000 mm, and subsequently Ni, Fe, Pd, Pt, Rh, Re, Ru A metal film 15 containing at least one of Co, In, Nb, V, Mo, W, and Zr is formed to a thickness of 20 to 200 mm. The metal film 15 is made of, for example, Ni alone. The metal film 15 is formed of any one of Ni, Fe, Pd, Pt, Rh, Re, Ru, Co, In, Nb, V, Mo, W, and Zr, or one of them. It is comprised as an alloy containing the above.

  Next, as shown in FIG. 6C, a photoresist film 16 is applied and formed, and exposure is performed using a mask (not shown) for forming a predetermined pixel region.

  Next, as shown in FIG. 6D, a pattern of the photoresist film 16 is formed using an organic alkaline photoresist developer.

  Next, as shown in FIG. 6E, collective etching is performed to remove the reflective film 14 and the metal film 15 simultaneously using a solution containing phosphoric acid, nitric acid, and acetic acid, thereby forming a pixel region G2.

  As described above, when the photoresist film 16 is formed on the reflective film 14 and the development process is performed, when an organic alkaline photoresist developer is used, Al is eluted into the developer. When this developing solution reaches the ITO film 37 on the source terminal 34 and the ITO film 38 on the gate terminal 35 from the pinhole of the reflective film 14 or the like, the ITO films 37 and 38 are reduced and corroded by the electrolytic corrosion reaction. Here, the corrosion of ITO occurs when the potential becomes −1.3 V or less. The potential when Al is immersed in the developer alone is -1.93 V, and in the developer from which Al is eluted, the ITO film is pulled down to a potential lower than the corrosion potential. Arise. Therefore, in order to prevent corrosion of the ITO films 37 and 38, it is necessary to maintain the potential of ITO at a potential higher than -1.3V.

  On the other hand, for example, the potential when Ni is immersed in a developer is 0.8 V, which is higher than the corrosion potential of ITO (noble). Further, as described above, the potential when Fe, Pd, Pt, Rh, Re, Ru, Co, In, Nb, V, Mo, W, and Zr are immersed in the developer is also −0.9 to +0. 1, which is higher than the corrosion potential of ITO.

  In the second embodiment, the TFT substrate 40 constituting the reflective liquid crystal display device forms the metal film 15 that raises the potential of Al in the developer on the reflective film 14, so that even when Al is eluted, The potential of the developer is maintained at a potential higher than the corrosion potential of ITO. Thereby, even if the developer reaches the ITO films 37 and 38, the ITO films 37 and 38 are not corroded.

Embodiment 3.
FIG. 7 is a plan view showing a schematic configuration when a TFT substrate used in the electroluminescent display device according to the third embodiment is completed. In FIG. 7, each pixel region G3 provided on the TFT substrate includes an anode electrode 25 having a reflective film electrically connected to the drain electrode 8, and an organic electroluminescent layer (organic EL layer) formed thereon. ) 27 and a cathode electrode 28 formed thereon. The anode electrode 25, the organic electroluminescent layer 27, and the cathode electrode 28 are formed on the entire surface of the pixel region G3.

  8 shows a cross section of a terminal group for applying a display signal and a voltage to a drive element of an electroluminescent display device, and a cross section seen from the direction of arrow CC of the TFT substrate shown in FIG. It is shown as a cross-sectional view. In FIG. 8, 1 is an insulating substrate, 2 is a gate electrode, 36 is a gate wiring, and 35 is a gate terminal, and the first insulating film 4 is provided thereon. A plurality of gate terminals 35 are arranged. A semiconductor film 5 and an ohmic contact film 6 are provided on the gate electrode 2 via the first insulating film 4. Reference numeral 7 denotes a source electrode, and reference numeral 8 denotes a drain electrode, which form a driving element 51 for driving a pixel by the above-described members.

  Reference numeral 34 denotes a source terminal, and 24 denotes a cathode ground (cathode ground) electrode. A second insulating film 9 and an interlayer insulating film 10 are formed on the upper layer thereof. A plurality of source terminals 34 and cathode grounding electrodes 24 are also arranged. Reference numerals 37 and 38 denote ITO films provided on the upper layers of the source terminal 34 and the gate terminal 35, respectively. The pixel region G3 is provided with a reflective film and the anode electrode 25 provided with the metal film 18, and between adjacent pixels. An organic resin film 26 that is a frame layer that is separated into a bank shape, an organic electroluminescent layer 27 made of an organic material, and a cathode electrode 28 are laminated to form. The organic electroluminescent layer 27 made of an organic material is generally formed of at least three layers of a hole transport layer, a light emitting (EL) layer, and an electron transport layer. Reference numeral 33 denotes a sealing material made of glass or the like for shielding the entire pixel region G3 including the organic electroluminescent layer 27 from moisture and impurities.

  Next, a manufacturing method of the TFT substrate 50 will be described in detail with reference to FIG. FIG. 9 is a cross-sectional view for explaining a method of manufacturing the TFT substrate 50 used in the electroluminescent display device according to the third embodiment.

  Hereinafter, an embodiment of a method for manufacturing the TFT substrate 50 will be described with reference to FIGS. In FIG. 9A, Cr or the like is formed as a first metal thin film on the insulating substrate 1 to a thickness of 2000 mm by sputtering, and the gate electrode 2, the gate terminal 35 and the gate are formed by a photolithography process. A wiring 36 is formed.

  Subsequently, 4000 nm of SiN is sequentially formed as the first insulating film 4 by CVD, and 1500 nm of a-Si is formed as the semiconductor film 5 and n + -a-Si is formed as the ohmic contact film 6 in a thickness of 300 mm. Then, the semiconductor film 5 and the ohmic contact film 6 are formed by a photolithography process.

  Next, as a second metal thin film, Cr or the like is formed to a thickness of 2000 mm using a sputtering method, and the source terminal 34, the source electrode 7, the drain electrode 8, and the cathode ground (cathode ground) are formed by a photolithography process. A working electrode 24 is formed.

  Next, SiN is formed to a thickness of 1000 mm as the second insulating film 9 using the CVD method. Subsequently, as an interlayer insulating film 10, for example, a product name PC335 manufactured by JSR, which is an acrylic photosensitive resin film, is formed by spin coating so as to have a film thickness of about 2 μm, and a photolithography process is used. The contact hole 22 is formed on the source terminal 34, the contact hole 23 is formed on the gate terminal 35, the contact hole 29 is formed on the cathode grounding electrode 24, and the contact hole 30 is formed on the drain electrode 8.

  Next, ITO is formed as a transparent conductive film with a thickness of 1000 mm using a sputtering method, and the ITO film 37 is formed on the source terminal 34, the ITO film 38 is formed on the gate terminal 35, and the cathode is grounded by a photolithography process. An ITO film 31 is formed on the electrode 24 as a terminal pad pattern.

  Next, as shown in FIG. 9B, as the anode electrode 25, a reflective film 17 containing at least Al is formed on the entire surface with a thickness of 3000 mm using a sputtering method. Subsequently, Ni, Pd, Pt, A metal film 18 containing at least one of Rh, Re, Co, Mo, W, and Zr is formed to a thickness of 20 to 200 mm. Subsequently, a photoresist film 19 is applied and formed, and exposure is performed using a mask (not shown) having a pattern corresponding to a predetermined shape. The metal film 18 is composed of, for example, Ni alone. The metal film 18 is composed of any one of Ni, Pd, Pt, Rh, Re, Co, Mo, W, and Zr, or some of them as an alloy.

Next, as shown in FIG. 9C, a pattern of the photoresist film 19 is formed using an organic alkaline photoresist developer.
Next, as shown in FIG. 9D, the reflective film 17 and the metal film 18 are simultaneously etched using a solution containing phosphoric acid, nitric acid, and acetic acid (development process) to form a pixel region G3.

  As described above, when the development process is performed after the photoresist film 19 is formed on the reflective film 17 and the exposure is performed with a predetermined pattern mask, the above-described organic alkali-based photoresist developer is generally used. When used, a part of Al in the reflective film 17 is eluted into the developer. If there is a pinhole in the Al of the reflective film 17, the reflective film 17 in the developing solution becomes the ITO film 37 on the source terminal 34, the ITO film 38 on the gate terminal 35, and the ITO on the cathode grounding electrode 24. It becomes a counter electrode with the film 31, and an electrolytic corrosion reaction occurs. As a result, the ITO films 37, 38, and 31 patterns, which have an overwhelmingly smaller volume than the Al-based reflective film 17, cause severe reduction corrosion. The corrosion of ITO by this electrolytic corrosion reaction proceeds when the potential in the developer becomes −1.3 V or less. The potential when Al is immersed in the developer alone is -1.93 V, and in the developer solution from which Al is eluted, the ITO film is lowered to a potential lower than the corrosion potential. Corrosion occurs. Therefore, in order to prevent corrosion of the ITO films 37, 38 and 31, it is necessary to maintain the potential of the ITO films 37, 38 and 31 at a potential higher than −1.3V.

  On the other hand, for example, the potential when Ni is immersed in the developer is 0.8 V, which is higher than the corrosion potential of the ITO films 37, 38, 31 (noble). Further, as described above, the potential when Pd, Pt, Rh, Re, Co, Mo, W, Zr, etc. are immersed in the developer is −0.9 to +0.1 V, and the ITO in the developer is ITO. It is possible to raise the potential to a level that does not corrode the film.

  In the third embodiment, since the metal film 18 for raising the potential of Al in the developer is formed on the reflective film 17, even when Al is eluted, the potential of the developer is higher than the corrosion potential of ITO. Maintained. Thereby, even if the developing solution reaches the ITO films 37, 38, 31, the ITO films 37, 38, 31 are not corroded.

  Further, since Ni or the like used for the metal film 18 has a reflectance lower than that of Al and has a slower etching rate, the thickness of the metal film 18 is set to 200 mm or less in order to maintain a high reflectance and perform batch etching. It is desirable. If the metal film 18 is formed with a thickness of 20 mm or more, it can be controlled to have a uniform thickness. Therefore, the film thickness of the metal film 18 is desirably 20 to 200 mm.

  As described above, the metal film 18 is formed on the reflective film 17 as the anode electrode 25. The metal film 18 is at least one of Ni, Pd, Pt, Rh, Re, Co, Mo, W, and Zr. You may form with the film thickness of 20 to 1000 mm as Al alloy containing. For example, an Al alloy containing 5 at% of Ni as an additive element can be formed on the reflective film 17 with a thickness of 500 mm. Since such an Al alloy contains Al as a main component, the reflectance is not impaired, and the potential of Al in the developer can be maintained higher than the corrosion potential of ITO. Further, since the etching rate can be made close to Al, the cross-sectional shape of the pattern after etching can be made smooth, which is more preferable. Furthermore, the work function can be made higher than that of Al (3.8 to 4.3 eV). When the metal film 18 is an Al alloy of Al and Ni, Pd, Pt, Rh, Re, Co, Mo, W, and Zr, the composition ratio of these additive elements is the Al ratio of the metal film 15 in the first embodiment. It is appropriate to make it the same as the composition ratio of the alloy. At this composition ratio, the work function value of the metal film 18 is around 4.2V.

  Further, a second metal film containing at least one of Cr, Ti, Ta, and Mo may be further formed to a thickness of 50 to 1000 mm below the reflective film 17 of the anode electrode 25 (not shown). ) By further forming these second metal films, the coverage of the anode electrode 25 at the underlying step portion can be improved, the disconnection of the step can be prevented, and the lower drain electrode 8 via the contact hole 30 can be prevented. The electrical contact resistance value can be lowered. Thereby, lighting display defects of the pixels can be prevented. In particular, it is preferable to use Mo because the entire anode electrode 25 made of the reflective film 17 and the metal film 18 including the lower layer Mo can be simultaneously etched by the Al etching solution.

  Next, as shown in FIG. 9E, an organic resin film 26 made of polyimide or the like is formed by coating in order to form the organic electroluminescent layer 27 in the pixel portion 32. The organic resin film 26 is formed by a photoengraving process so that a bank-like convex portion is formed in a frame shape between adjacent pixels so as to surround each pixel portion 32. As the organic resin film 26, it is desirable to use a polyimide-based material with little adsorbed moisture that adversely affects the characteristics and reliability of the organic EL layer forming the organic electric field layer 27. In Embodiment 3, the product name DL100 manufactured by Toray was applied with a film thickness of about 2 μm, and the organic resin film 26 was formed by a photolithography process.

  Next, an organic EL material to be the organic electroluminescent layer 27 is formed on the pixel portion 32 by using a method such as vapor deposition. In the third embodiment, the organic electroluminescent layer 27 is formed by laminating a hole transport layer, an organic EL layer, and an electron transport layer in this order. The hole transport layer can be selected widely from known organic materials such as triarylamines, aromatic hydrazones, aromatic substituted pyrazolines, stilbenes, such as N, N-diphenyl-N, N-bis. (3-methylphenyl) -1,1′-diphenyl-4,4′diamine (TPD) or the like is formed to a thickness of 10 to 2000 mm. Known organic materials such as dicyanomethylenepyran derivatives (red light emission), coumarin (green light emission), quinacridone (green light emission), tetraphenylbutadiene (blue light emission), distyrylbenzene (blue light emission), etc. Is formed with a thickness of 10 to 2000 mm. As the electron transport layer, a material selected from known oxadiazole derivatives, triazole derivatives, coumarin derivatives and the like is formed with a thickness of 10 to 2000 mm.

  Next, an ITO film made of a transparent conductive film is formed as the cathode electrode 28 to a thickness of 1000 mm using a sputtering method. The cathode electrode 28 is connected to the lower organic electroluminescent layer 27 in the pixel portion 32 and is also connected to the lower cathode grounding electrode 24 through the contact hole 29. The cathode electrode 28 preferably has a high flatness on the film surface. Therefore, it is preferable to form an amorphous ITO film having no crystal grain boundary in the film structure. The amorphous ITO film can be formed, for example, by sputtering in a gas in which H 2 O gas is mixed with Ar gas. It is also possible to use an IZO film in which indium oxide and zinc oxide are mixed, or an ITZO film in which zinc oxide is mixed in an ITO film.

  Finally, in order to prevent deterioration of the light emission characteristics of the display panel due to moisture or impurities, the entire pixel portion 32 is replaced with an inert gas such as Ar or N 2 gas, and then sealed with a sealing material 33. Thus, the display panel of the electroluminescent display device is completed. The sealing material 33 can be formed by using, for example, transparent glass or the like, forming a sealant on the outer peripheral portion of the display panel, and pressing the sealant.

  The reflective film 17 may be an Al alloy containing at least one of Cu, Si, Nd, Y, and Hf. Thereby, since the crystal grain growth is suppressed as compared with the case where the reflective film 17 is formed of pure Al to which no impurity is added, the surface unevenness is reduced. For this reason, the surface of the anode electrode 25 is a dense flat surface, which is preferable because the light emission efficiency and light emission display quality of the organic electroluminescent layer 27 can be further improved.

  When the metal film 18 is formed of Ni, Pd, Pt, Rh, Re, and Co, the work function can be made higher than that of Al (3.8 to 4.3 eV), and the work function is 4. Since it has a value of 5 eV or more, the efficiency of hole carriers injected into the organic electroluminescent layer 27 made of organic EL or the like as the anode electrode 25 can be increased, so that the luminous efficiency of organic EL display can be increased.

  The organic electroluminescent layer 27 has a structure in which a hole transport layer, an organic EL layer, and an electron transport layer are sequentially stacked. In order to further increase the light emission efficiency of the organic electroluminescent layer 27, the hole transport layer is a hole injection layer. It is also possible to adopt a configuration in which the hole transport layer is composed of two layers and the electron transport layer is composed of an electron transport layer and an electron injection layer.

  In the above-described embodiment, an a-Si (amorphous silicon) film is used as the semiconductor film 6 of the TFT serving as a driving element for driving the pixel. However, the present invention is not limited to this, and polycrystalline silicon (p- Si) film may be used. Further, a driving IC circuit for driving a display signal may be formed around the display panel at the same time.

  Further, although the gate electrode is formed in the lower layer, the present invention is not limited to this, and a top gate type in which the gate is formed in the upper layer may be used.

  As the transparent conductive film, not only the ITO film but also an IZO film composed of indium oxide and zinc oxide and an ITZO film composed of indium oxide, tin oxide and zinc oxide can be used. The same effect can be obtained by using an IZO film or an ITZO film.

FIG. 1 is a plan view showing a configuration of a TFT substrate used in the transflective liquid crystal display device according to Embodiment 1 of the present invention. 2 is a cross-sectional view taken along line AA in FIG. 3A to 3E are cross-sectional views showing each manufacturing process of the TFT substrate used in the first embodiment. FIG. 4 is a plan view showing a configuration of a TFT substrate used in the reflective liquid crystal display device according to the second embodiment of the present invention. FIG. 5 is a cross-sectional view showing a cross section taken along line BB of FIG. 4 and a cross section of the terminal portion. 6A to 6E are cross-sectional views showing respective manufacturing steps of the TFT substrate used in the second embodiment. FIG. 7 is a plan view showing a configuration of a TFT substrate used in the electroluminescent display device according to the third embodiment of the present invention. FIG. 8 is a cross-sectional view showing a cross section taken along line CC of FIG. 7 and a cross section of the terminal portion. 9A to 9E are cross-sectional views showing respective manufacturing steps of the TFT substrate used in the third embodiment.

1: insulating substrate, 2: gate electrode, 3: auxiliary capacitance electrode, 4: first insulating film,
5: Semiconductor film, 6: Ohmic contact film, 7: Source electrode, 8: Drain electrode,
9: second insulating film, 10: interlayer insulating film, 11: transmissive region pattern,
12: Contact hole, 13: ITO film, 14: Reflective film, 15: Metal film
16: Photoresist film, 17: Reflective film, 18: Metal film, 19: Photoresist film,
20, 40, 50: TFT substrate, 21: Liquid crystal driving element, 22, 23: Contact hole, 24: Electrode for cathode ground (cathode ground), 25: Anode electrode, 26: Organic resin film,
27: Organic electroluminescent layer, 28: Cathode electrode, 29, 30: Contact hole,
31: Transparent conductive film (ITO film), 32: Pixel portion, 33: Sealing material, 34: Source terminal,
35: gate terminal, 36: gate wiring (intersection of source wiring),
37, 38: ITO film, G1, G2, G3: pixel region, 51: drive element.

Claims (5)

A transflective liquid crystal display device comprising a transmissive region for transmitting backlight light and a reflective region for reflecting ambient light incident from the outside on an insulating substrate together with a liquid crystal driving element,
The reflective region has a reflective film provided on and joined to the transparent conductive film that forms the transmissive region, and the reflective film is made of Ni, Fe, Pd, Pt, Rh, Ru, which are group 8 elements. A transflective liquid crystal display device formed of an Al alloy containing at least one of Co and Co. A method of manufacturing a transflective liquid crystal display device comprising a transmissive region for transmitting backlight light and a reflective region for reflecting ambient light incident from the outside together with a liquid crystal driving element on an insulating substrate. ,
A reflective film made of an Al alloy containing at least one of Ni, Fe, Pd, Pt, Rh, Ru, and Co as group 8 elements is formed on the transparent conductive film .
Forming a mask pattern corresponding to the previous SL transmissive area before Symbol reflective film, etching the reflective film through the mask pattern, the form of the transmissive area portion where the reflective film is etched, the reflection A method of manufacturing a transflective liquid crystal display device , wherein the reflective region is formed in a portion where a film remains . A TFT substrate configured by arranging a transmission region for transmitting backlight light and a reflection region for reflecting ambient light incident from the outside on an insulating substrate together with a liquid crystal driving element,
The reflective region has a reflective film provided on and joined to the transparent conductive film that forms the transmissive region, and the reflective film is made of Ni, Fe, Pd, Pt, Rh, Ru, which are group 8 elements. A TFT substrate formed of an Al alloy containing at least one of Co and Co. A pixel region that reflects ambient light incident from the outside, a liquid crystal driving element, and a terminal group that is covered with a transparent conductive film and applies a display signal and a voltage to the liquid crystal driving element are arranged on an insulating substrate. A TFT substrate,
2. The TFT substrate according to claim 1, wherein the pixel region is formed of an Al alloy containing at least one of Ni, Fe, Pd, Pt, Rh, Ru, and Co as group 8 elements. A method for manufacturing a TFT substrate comprising a transmissive region for transmitting backlight light and a reflective region for reflecting ambient light incident from the outside together with a liquid crystal driving element on an insulating substrate,
And therewith bonded on the transparent conductive film to form Ni, Fe, Pd, Pt, Rh, Ru, a reflective film made of Al alloy containing at least any one of Co is Group 8 elements,
Forming a mask pattern corresponding to the transmissive area before Symbol reflective film, through the mask pattern etching the reflecting film, the formed transparent zones within which the reflective film is etched, the reflective film And a step of forming the reflective region in a portion where the metal remains .