Display panel manufacturing method, display panel, and display apparatus

A method of manufacturing a display panel having a display part and a terminal part each formed on a different area on a TFT substrate, comprising: a step of forming the display part on the TFT substrate; a step of forming a conductive layer of a conductive metal oxide or a metal on an area where the terminal part is to be formed; a step of forming a chemical vapor deposition layer of an inorganic compound by a chemical vapor deposition method so that the chemical vapor deposition layer covers the display part and comes into contact at least with an upper surface of the conductive layer and so that the upper surface of the conductive layer alters; and a step of removing a portion of the chemical vapor deposition layer on the conductive layer.

TECHNICAL FIELD

The present disclosure relates to a method of manufacturing a display panel, a display panel, and a display apparatus.

BACKGROUND ART

In manufacturing a display panel having a display part formed on the middle area of the substrate and a terminal part formed on the peripheral area of the substrate, there is a conventional approach to prevent the alteration of the display part due to moisture, gas, or the like by forming a passivation layer of SiN (silicon nitride) so as to cover the display part by using a chemical vapor deposition (CVD) method. According to this approach, the passivation layer needs to cover the entire display part. However, if the terminal part is also covered with the passivation layer, the passivation layer causes low conductivity between the terminal part and the wiring terminals connected to the terminal part. In view of this problem, the passivation layer is formed by selective film formation using a mask, in order to prevent the passivation film from covering the terminal part.

In this regard, it is not easy to form the passivation layer exactly on a desired area by a CVD method. In order to completely cover the display part while not covering the terminal part, it is necessary to provide a wide gap between the display part formation area where the display part is to be formed and the terminal part formation area where the terminal part is to be formed so that the periphery of the passivation layer does not overlap the terminal part. However, such a wide gap is not preferable because it increases the size of the display panel.

According to a manufacturing method disclosed in Patent Literature 1, the passivation film is formed by the following steps: first, as shown inFIG. 13A, a display part905composed of a bottom electrode902, an organic light-emitting layer903and a top electrode904is formed on a substrate901, while an adhesive anisotropic conductive film (ACF)907with a protective laminate906is attached to the area on the bottom electrode902where the terminal part is to be formed; next, as shown inFIG. 13B, an SiN layer908is formed to cover the display part905and the ACF907; and finally, as shown inFIG. 13C, the formation of the passivation layer909is completed by removing the portion of the SiN layer908on the protective laminate906by peeling off the protective laminate906. With this method, the ACF907will not be covered with the passivation layer909, and hence the conductivity between the ACF907and the wiring terminals will not be degraded.

CITATION LIST

Patent Literature

SUMMARY

However, according to the manufacturing method disclosed in Patent Literature 1, it is necessary to attach the ACF907before forming the SiN layer908. Therefore, after sequentially forming the bottom electrode902, the organic light-emitting layer903and the top electrode904, it is necessary to suspend the lamination process to take out the substrate901from a chamber and to attach the ACF907to the substrate901. The substrate901is then put back into the chamber to resume the lamination process, and, finally, the SiN layer908is formed. In this way, the lamination process will be complicated. In addition, since the substrate901needs to be taken into and out of the chamber, there is a risk of foreign objects such as dust attaching to the substrate901. Therefore, with this manufacturing method, it is necessary to take a measure to reduce the risk. Therefore, with this method, it is impossible to manufacture display panels efficiently.

Considering the above problems, one non-limiting and exemplary embodiment provides a display panel manufacturing method and a display apparatus manufacturing method that can be applied for accurately and efficiently forming a passivation layer on a desired area.

In one general aspect, the techniques disclosed here feature a method of manufacturing a display panel having a display part and a terminal part each formed on a different area on a substrate, comprising: a display part formation step of forming the display part on the substrate; a conductive layer formation step of forming a conductive layer of a conductive metal oxide or a metal on an area on the substrate where the terminal part is to be formed; a chemical vapor deposition layer formation step of forming a chemical vapor deposition layer of an inorganic compound by a chemical vapor deposition method so that the chemical vapor deposition layer covers the display part and comes into contact at least with an upper surface of the conductive layer and so that the upper surface of the conductive layer alters; and a removal step of removing a portion of the chemical vapor deposition layer by peeling the portion off, the portion being located on the conductive layer.

Note that the term “remove” in the present disclosure means removal by physical means, and does not include removal by chemical means. In addition, grinding or the like is not considered as a physical means. One example of the removal in the present disclosure is physically removing the portion while keeping the portion in a layer-like or film-like shape.

The method includes: a conductive layer formation step of forming a conductive layer of a conductive metal oxide or a metal on an area on the substrate where the terminal part is to be formed; a chemical vapor deposition layer formation step of forming a chemical vapor deposition layer of an inorganic compound by a chemical vapor deposition method so that the chemical vapor deposition layer covers the display part and comes into contact at least with an upper surface of the conductive layer and so that the upper surface of the conductive layer alters; and a removal step of removing a portion of the chemical vapor deposition layer by peeling the portion off, the portion being located on the conductive layer. Therefore, a sealing layer as the residue of the chemical vapor deposition layer after the removal step can be formed exactly on the desired area. In addition, since it is unnecessary to attach the ACF in the middle of the process for forming the display part, the sealing layer can be effectively formed.

These general and specific aspects may be implemented using a device.

DETAILED DESCRIPTION

The following describes a display panel manufacturing method, a display apparatus manufacturing method, a display pane, and a display apparatus each pertaining to an aspect of the present invention, with reference to the drawings. Note that in the drawings the components may be not drawn to scale.

[Overview of Aspects of the Present Invention]

In one general aspect, the techniques disclosed here feature a method of manufacturing a display panel having a display part and a terminal part each formed on a different area on a substrate, comprising: a display part formation step of forming the display part on the substrate; a conductive layer formation step of forming a conductive layer of a conductive metal oxide or a metal on an area on the substrate where the terminal part is to be formed; a chemical vapor deposition layer formation step of forming a chemical vapor deposition layer of an inorganic compound by a chemical vapor deposition method so that the chemical vapor deposition layer covers the display part and comes into contact at least with an upper surface of the conductive layer and so that the upper surface of the conductive layer alters; and a removal step of removing a portion of the chemical vapor deposition layer by peeling the portion off, the portion being located on the conductive layer.

The conductive layer may be made of a conductive metal oxide, and the chemical vapor deposition layer formation step may include a sub-step of causing alteration of the conductive metal oxide contained in the upper surface of the conductive layer by reduction thereof using a reducing gas.

The method may further comprise: an adhesive tape attaching step of attaching adhesive tape onto the portion of the chemical vapor deposition layer after performing the chemical vapor deposition layer formation step and before performing the removal step, wherein in the removal step, the portion of the chemical vapor deposition layer may be peeled off by pulling the adhesive tape off.

The method may further comprise an atomic layer deposition film formation step of forming an atomic layer deposition film on the chemical vapor deposition layer by an atomic layer deposition method after performing the chemical vapor deposition layer formation step and before performing the removal step.

The method may further comprise an adhesive tape attaching step of attaching adhesive tape onto a portion of the atomic layer deposition film after performing the atomic layer deposition film formation step and before performing the removal step, the portion being located above the conductive layer, wherein in the removal step, the portion of the chemical vapor deposition layer and the portion of the atomic layer deposition film may be peeled off by pulling the adhesive tape off.

The conductive metal oxide may be ITO or IZO.

The reducing gas may be SiN or SiH4.

The techniques disclosed here also feature a display panel having a display part and a terminal part each formed on a different area on a substrate, wherein the display part is covered with a passivation layer of an inorganic compound formed by a chemical vapor deposition method, the terminal part is made of a conductive metal oxide or a metal and is not covered with the passivation layer, and at least part of the upper surface of the terminal part is altered by the vapor deposition method.

The techniques disclosed here also feature a display apparatus having the display panel.

FIG. 1shows an overall structure of a display apparatus according to one aspect of the present invention. As shown inFIG. 1, a display apparatus1pertaining to one aspect of the present invention includes a display panel100, a drive control unit200, and a wiring board300. The display panel100is, for example, an organic EL panel utilizing electroluminescence effects. The drive control unit200includes four drive circuits210and a control circuit220. The wiring board300is, for example, a flexible wiring board, on which an IC as the drive circuit210is mounted.

FIG. 2is a perspective view showing connections between the display panel100and the wiring board300. As shown inFIG. 2, a display part101is formed on the middle of the display panel100(i.e. the area surrounded by a two-dot chain line inFIG. 2), and a terminal part114including a plurality of terminals (seeFIGS. 3 and 5Athrough5C) is formed on the peripheral area surrounding the middle area, along all the four sides of the display panel100.

The wiring board300is, for example, made by forming a conductive pattern (omitted from the drawing) of copper or the like on a base film310made of polyimide. In each connector of the wiring board300, a wiring terminal320(seeFIG. 3) is formed on the bottom surface (i.e. the main surface) of the base film310facing the display panel100(i.e. facing a TFT substrate111). The wiring terminals320respectively correspond in position to the terminals in the terminal part114, and are electrically connected to the conductive pattern.

The wiring terminals320formed on the connectors of the wiring board300are adhered to the peripheral area of the TFT substrate111via an adhesive anisotropic conductive film (ACF)400along all the four sides of the display panel100. The ACF400electrically connects the terminals in the terminal part114of the display panel100with their corresponding wiring terminals320of the wiring board300.

Note that the terminal part114is not necessarily formed along all the four sides of the display panel100. The terminal part114may be formed along only one side, two sides, or three sides of the display panel100. The drive circuit210and the wiring board300only need to adhere to the area where the terminal part114is formed.

FIG. 3shows a cross-section along the A-A line shown inFIG. 2. As shown inFIG. 3, the display panel100includes, for example, a device substrate110and a color filter (CF) substrate120. The device substrate110and the CF substrate120are arranged face to face.

A sealer102ais interposed between the device substrate110and the CF substrate120, and the gap between the device substrate110and the CF substrate120is filled with a resin layer102b. The sealer102aand the resin layer102bare made of dense resin material (such as silicone resin or acrylic resin), and seal the display part101of the device substrate110so as to prevent organic light-emitting layers116from coming into contact with moisture or gas.

The display part101is formed on the upper surface of the TFT substrate111(i.e. the main surface that is closer to the CF substrate120than the other surface is. In the following description, in regards to each of the layers constituting the device substrate110, the surface closer to the CF substrate120is referred to as “the upper surface”). The display part101includes a plurality of pixels arranged in a matrix. R (red), G (green) or B (blue) light emitted from each pixel passes through the CF substrate120, and thus a color image is displayed on the front side of the display panel100. The part terminal114is formed on the peripheral area surrounding the display part101formed on the upper surface of the TFT substrate111. Although the above example is provided with the CF substrate120, the CF substrate is not essential.

The device substrate110includes a TFT substrate111and an electro luminescence (EL) substrate124. The EL substrate124is a laminate formed on the upper surface of the TFT substrate111, and includes a planarizing film112, bottom electrodes113, contact holes113X, an anode ring113Y, banks115, organic light-emitting layers116, an electron transport layer116X, a top electrode117, a passivation layer118, a protective film119, and so on. Each of the pixels constituting the display part101on the device substrate110is a top-emission organic EL element composed of the bottom electrode113, the organic light-emitting layer116, the electron transport layer116X and the top electrode117.

The TFT substrate111is formed by, for example, laminating a TFT layer111bon the upper surface of a substrate111a. The TFT layer111bincludes, for example, SD wiring111cand a passivation film111d. The substrate111aincludes a base substrate made of insulative material, and a plurality of TFTs and their extraction electrodes are formed on the upper surface of the base substrate in a predetermined pattern. Examples of the insulative material are alkali-free glass, soda glass, nonfluorescent glass, phosphate glass, borate glass, quartz, acrylic resin, styrenic resin, polycarbonate resin, epoxy resin, polyethylene, polyester, silicone resin, and alumina. The passivation film111dis a thin film made of SiO (silicon oxide) or SiN (silicon nitride), and protects the SD wiring111cby covering it.

The planarizing film112is made of insulating material such as polyimide or acrylic resin, and planarizes the uneven upper surface of the passivation film111d. Note that the planarizing film112is not essential.

The bottom electrodes113are electrically connected to the TFT layer111bvia the contact holes113X. Note that each bottom electrode113may have a double-layer structure including a metal layer and a metal oxide layer, for example. The metal layer is made of light-reflective conductive material and formed in a matrix so as to correspond in position to the pixels. Examples of the light-reflective conductive material are Ag (silver), APC (alloy of silver, palladium, and copper), ARA (alloy of silver, rubidium, and gold), MoCr (alloy of molybdenum and chromium), NiCr (alloy of nickel and chromium). The metal oxide layer is made of conductive material such as ITO (indium tin oxide) or IZO (indium zinc oxide), and is formed on the metal layer so as to cover the metal layer.

Each terminal114has a double-layer structure including a metal layer114aand a metal oxide layer114b, for example. Each metal layer114ais composed of a portion of the SD wiring111c, and is made of high-conductive material with low electric resistance and high process stability. Examples of the high-conductive material include metals such as Cr, Mo, Al, Ti and Cu, and alloys containing such metals (e.g. MoW, MoCr, NiCr). The metal layers114aare formed on the peripheral area on the TFT substrate111along all the four sides. Here, every two or more of the metal layers114aconstitute a group, and the groups are arranged with intervals. The metal oxide layers114bare made of light transmissive material such as ITO or IZO, and are formed on the metal layers114aso as to cover them. Note that a substance resulting from alteration of metal oxide (i.e. a residue of a damaged layer114e, which will be described later) remains on the surface of each metal oxide layer114b.

The banks115are made, for example, of insulative organic material (e.g. acrylic resin, polyimide resin, novolac-type phenolic resin), and are formed on the middle area on the TFT substrate111without covering the areas where the bottom electrodes113are formed. Although the banks115of the present embedment are pixel banks having a lattice structure, they may be line banks having a stripe structure.

The electron transport layer116X is made, for example, of barium, phthalocyanine, lithium fluoride, or a combination thereof, and has the function of transporting electrons injected through the top electrode117to the organic light-emitting layers116.

The top electrode117is a transparent electrode that is made, for example, of a light-transmissive material such as ITO or IZO. The top electrode117is formed all over the display part101so as to cover the upper surfaces of the banks115and the organic light-emitting layers116.

The sealing layer118is, for example, a layer covering the display part101so as to seal the display part101and prevent the organic light-emitting layers116from coming into contact with moisture or gas. The sealing layer118is made, for example, of a light-transmissive material such as SiN, SiO, SiON (silicon oxynitride), SiC (silicon carbide), SiOC (silicon oxide containing carbon), and is formed on the top electrode117.

The protective film119is a layer covering the display part101so as to seal the display part101and prevent the organic light-emitting layers116from coming into contact with moisture or gas. The protective film119is made, for example, of a light-transmissive material such as Al2O3(aluminum oxide) or MN (aluminum nitride), and is formed on the sealing layer118. Since the protective film119is additionally formed on the sealing layer118, even when there are sealing deficiencies called pin holes in the sealing layer118, moisture or gas is prevented from entering into the sealing layer118through the pin holes.

In the above-described laminate structure of the EL substrate124, other one or more layers such as a hole transport layer and a hole injection layer may be additionally formed between the bottom electrodes113and the organic light-emitting layers116. Furthermore, other one or more layers such as an electron transport layer and an electron injection layer may be additionally formed between the organic light-emitting layers116and the top electrode117.

The CF substrate120includes: a glass substrate121; R, G and B color filters122formed on the bottom surface (i.e. the main surface closer to the device substrate110) of the glass substrate121; and a black matrix layer123.

The color filters122are light-transmissive layers made of a known resin material or the like, and each transmits visible light with a wavelength corresponding to R, G or B. The color filters122are formed in the areas corresponding one-to-one to the pixels.

The black matrix layer123is a black resin layer formed for the purpose of preventing external light from entering inside the panel, preventing the internal components from being seen through the CF substrate120, reducing the reflection of external light and improving the contrast of the120display panel100, for example. The black matrix layer123is made, for example, of an ultraviolet curable resin material containing black pigments that are highly light-absorbable and highly light-protective.

[Method of Manufacturing Display Panel and Display Apparatus]

The following describes a display panel manufacturing method pertaining to one aspect of the present invention.FIGS. 4 and 5are an illustration of a method of manufacturing a display panel pertaining to one aspect of the present invention.

First, as shown inFIG. 4A, a laminate114ccomposed of the metal layer114aand the conductive layer114dis formed on the area on the TFT substrate111where the terminal114is to be formed (hereinafter referred to as “terminal preparation area”). The laminate114cwill be the terminal114. More specifically, the terminal preparation area is removed from the passivation film111don the TFT substrate111so that the metal layer114a, which is a portion of the SD wiring111c, is exposed. Then, the conductive layer114dmade of a conductive metal oxide is formed on the exposed portion of metal layer114aby plasma deposition or sputtering.

Next, as shown inFIG. 4B, the planarizing film112(having a thickness of 4 μm, for example) is formed by, for example, spin-coating a resin and patterning the resin by photoresist/photo etching. Furthermore, the contact holes113X, the bottom electrodes113, and the anode ring113Y are formed.

The bottom electrodes113are formed by the following steps, for example: first, a metal thin film is formed by vacuum vapor deposition or sputtering, and then a metal layer is formed by patterning the metal thin film by photoresist/photo etching; next, a conductive metal oxide thin film is formed by plasma deposition or sputtering, and then a metal oxide layer is formed by patterning the metal oxide thin film by photoresist/photo etching.

Next, as shown inFIG. 4C, the banks115, the organic light-emitting layers116, the electron transport layer116X and the top electrode117are sequentially formed.

The banks115are formed by the following steps, for example: first, a bank material layer is formed to cover the entire area where the display part101is to be formed; and then portions of the bank material layer are removed by photoresist/photo etching. Note that the banks115may be pixel banks that extend in the column and row directions and have a lattice shape in plan view, or line banks that extend in either the column direction or the row direction and have a stripe shape.

Next, the recesses between the banks115are filled with ink for organic light-emitting layers by an inkjet method, for example. The ink is dried in reduced-pressure atmosphere at 25° C., and then baked. The organic light-emitting layers116are thus formed. Furthermore, the electron transport layer116X is formed by ETL deposition so as to cover the banks115and the organic light-emitting layers116. The method of filling the recesses between the banks115with ink is not limited to the inkjet method. For example, a dispenser method, a nozzle coating method, a spin coating method, intaglio printing or letterpress printing may be used.

Next, the top electrode117is formed so as to cover the banks115and the organic light-emitting layers116. The top electrode117is formed by, for example, deposition of a light-transmissive material.

This completes the display part formation step of forming the display part101on the TFT substrate111, and the conductive layer formation step of forming the conductive layer114dmade of a conductive metal oxide on the area on the TFT substrate111where the terminal114is to be formed. In the above-described embodiment, the conductive layer formation step is performed before the display part formation step. However, the conductive layer formation step may be performed after the display part formation step, or the conductive layer formation step may be performed simultaneously with the process of forming the bottom electrode, which is included in the display part formation step.

Next, as shown inFIG. 4D, a chemical vapor deposition layer118amade of an norganic compound (having a thickness of 620 nm, for example) is formed on the entire upper surface of the TFT substrate111by a CVD method. In this process, the exposed portions of the conductive layer114d(i.e. the upper surface and the side surface of the conductive layer114d) alter. As a result, a damaged layer114eis formed on the surface of the conductive layer114d. This completes the chemical vapor deposition layer formation step of forming the chemical vapor deposition layer so that the chemical vapor deposition layer covers the display part101and comes into contact at least with the upper surface of the conductive layer114dand the upper surface of the conductive layer114dalters. At this point, the conductive layer114dis composed of the damaged layer114eand the metal oxide layer114bunderneath the damaged layer114e.

The CVD method specifically is a plasma CVD method using a reducing gas such as SiN or SiH4(monosilane). When the chemical vapor deposition layer118ais formed, the upper surface and the side surface of the conductive layer114dare subject to reduction and alteration due to the reducing gas. As a result, the damaged layer114eis formed.

When SiH4is used as the reducing gas, desirable conditions for the film formation are as follows: the film formation temperature is from 50° C. to 70° C.; the film formation pressure is from 80 Pa to 120 Pa; RF is from 1.1 kW to 1.7 kW; the volume of the flow of SiH4is from 120 sccm to 180 sccm; the volume of the flow of NH3is from 70 sccm to 100 sccm; the volume of the flow of N2is from 2800 sccm to 4200 sccm; and the duration of the film formation is from 130 sec to 190 sec. If the reducing power is too weak, the sealing property of the sealing layer118formed later will be insufficient. If the reducing power is too strong, the removability of the sealing layer118will be improved, but the display part101will be damaged.

Next, as shown inFIG. 4E, an atomic layer deposition film119a(with a thickness of 20 nm, for example) is formed all over the upper surface of the TFT substrate111by an atomic layer deposition (ALD) method. Specifically, an Al2O3film is formed under an atmosphere of Trimethylaluminum (TMA) gas by using oxygen plasma, for example. Desirable conditions for the film formation are as follows: the film formation temperature is from 75° C. to 95° C.; the film formation pressure is from 80 Pa to 120 Pa; RF is from 0.8 kW to 1.2 kW; and the film formation speed is from 0.12 nm/cycle to 0.18 nm/cycle.

Here, the ALD method is a method of depositing gas particles that are as small as atoms. Therefore, even if the selective film formation is performed by using a mask, the gas could enter the gap under the mask. It is thus difficult to form the film exactly on the desired area. In addition, since the atomic layer deposition film119ais dense, if this film lies on the terminal part114, the film prevents the conduction between the terminals in the terminal part114and the wiring terminals320. In contrast, by the manufacturing method pertaining to the present embodiment, only the desired portion of the chemical vapor deposition layer118acan be removed through the removal step, which will be described later. Therefore, there is no need of a mask, and the atomic layer deposition film119ais unlikely to be formed on the terminal part114.

Next, under the condition that the damaged layer114eremains on the surface of the conductive layer114das shown inFIG. 5A, adhesive tape500is attached onto a portion of the atomic layer deposition film119a, the portion being located above the damaged layer114e(which is also above the conductive layer114d) as shown inFIG. 4FandFIG. 5B. This completes the adhesive tape attaching step. Examples of the adhesive tape500include an ACF.

Next, by removing the adhesive tape500, the portion of the atomic layer deposition film119aabove the conductive layer114d, the portion of the chemical vapor deposition layer118aon the conductive layer114d, and the damaged layer114eof the conductive layer114dare peeled off together. As a result, a portion of the metal oxide layer114bis exposed. The area to be exposed is the area in which the adhesive tape500has been attached as depicted with the solid line B inFIG. 5C(See also the area B shown inFIG. 4G). If the adhesive tape500is not attached to the entire portion of the chemical vapor deposition layer118aon the conductive layer114d, the portion of the chemical vapor deposition layer118aon the conductive layer114dwill be partially removed as shown inFIG. 3andFIG. 5C, and the portion of the metal oxide layer114bwill be partially exposed. If this is the case, a portion of the damaged layer114eremains on the metal oxide114bin the area to which the adhesive tape500was not attached and which was thus not removed, as shown inFIG. 3.

Note that the adhesive tape500may be attached to the entire portion of the chemical vapor deposition layer118aon the conductive layer114dand the entire portion of the chemical vapor deposition layer118aon the conductive layer114dmay be removed.

This completes the removal step of removing the portion of the chemical vapor deposition layer118aon the conductive layer114d.

Since the portion of the atomic layer deposition film119aabove the conductive layer114dand the portion of the chemical vapor deposition layer118aon the conductive layer114dare removed, the electrical conductivity between the terminals in the terminal part114and the wiring terminals320will be excellent. Although it is desirable that the portion of the atomic layer deposition film119aabove the conductive layer114dand the portion of the chemical vapor deposition layer118aon the conductive layer114dare completely removed, residues of the portions may remain on the conductive layer114d. If this is the case, it is desirable that the amount of the residues is limited so as not to have an influence on the conductivity.

In the removal step, the damaged layer114emay be completely removed, partially removed, or not removed at all. If the damaged layer114eis completely removed, no residue of the damaged layer114ewill remain on the terminal part114. If only a portion of the damaged layer114eis removed, residues of the damaged layer114ewill remain on the terminal part114, and if the damaged layer114eis not removed at all, the entire damaged layer114ewill remain on the terminal part114. The damaged layer114e, if remaining on the terminal part114, has no influence on the conductivity. If part or all of the damaged layer114eis remaining on the terminal part114of a display panel, it can be assumed that the panel is the display panel100of the display apparatus1manufactured according to the method pertaining to the present invention.

In the removal step, since the damaged layer114elies on the surface of the conductive layer114d, the chemical vapor deposition layer118aand the atomic layer deposition film119aare removed together with the adhesive tape500from the TFT substrate111. These layers are removed at the interface between the damaged layer114eand the chemical vapor deposition layer118a, the interface between the damaged layer114eand the metal oxide layer114b, or at an area within the thickness of the damaged layer114e, because these areas are weak.

The reason for the weakness can be assumed as follows. For example, when the surface of the conductive layer114dis exposed to the reducing gas used in the chemical vapor deposition method, the metal oxide include in the surface of the conductive layer114dis partially reduced to metal. The partial loss of the metal oxide and the extraction of the metal forms concavities and convexities on the surface of the conductive layer114d, which leads to the degradation of the adhesiveness between the conductive layer114dand the chemical vapor deposition layer118a. The alteration of the surface of the conductive layer114dcan be observed from the blackening or whitening of the metal oxide layer114bafter the chemical vapor deposition. The metal oxide layer114bis made of ITO and is originally transparent.

FIG. 6is an electron micrograph of the surface of the test substrate. This substrate was prepared by forming a conductive layer made of ITO on a glass substrate, and underwent the following processes: first, the chemical vapor deposition layer is formed by a plasma CVD method; next, the atomic layer deposition film is formed by an ALD method; and finally, the layers are removed with an ACF.FIG. 7is an electron micrograph showing the cross-section along the line D shown inFIG. 6.FIGS. 8A and 8Bare enlarged electron micrographs respectively showing the areas E and F surrounded by the two-dot chain lines shown inFIG. 7.

As seen fromFIGS. 6 through 8, the portion of the chemical vapor deposition layer and the portion of the atomic layer deposition film on the conductive layer are almost completely removed by the removal step. InFIGS. 7 and 8, the layer composed of Al2O3is the atomic layer deposition film119a, the layer composed of SiN is the chemical vapor deposition layer118a, and the layer composed of ITO is the metal oxide layer114b.

The device substrate110is manufactured as described above.

In the manufacturing processes shown inFIGS. 4A through 4G, the step of disposing the CF substrate is omitted. In the case of disposing the CF substrate, it is desirable that the step of disposing the CF substrate is performed after the step of forming the atomic layer deposition film shown inFIG. 4Eand before the step of attaching the adhesive tape shown inFIG. 4F.

The influence of the chemical vapor deposition layer and the atomic layer deposition film on the conductivity was tested.FIG. 9shows the results of the tests about the influence of the chemical vapor deposition layer and the atomic layer deposition film on the conductivity. In the tests, a laminate was prepared by forming an ITO layer, an SiN layer, and an Al2O3film on a 100 mm square glass plate, the wiring board was connected to the laminate via an ACF, and the resistance of the laminate was measured with a resistance tester.

The ACF used in the tests contains 4 μm Ni-coated plastic particles as conductive particles. The wiring board was connected to the laminate via the ACF by using a device for thermal compression bonding with the following settings: the temperature was 250° C.; the duration was 15 sec; and the pressure was 120 Pa.

As shown inFIG. 9, the resistance of the laminate with an Al2O3film having a thickness of 2 nm (Test 2) was approximately 1.5 times the resistance of the laminate with no Al2O3film (Test 1). Furthermore the resistance of the laminate with an Al2O3film having a thickness of 5 nm (Test 3) was approximately 2 times, and the laminate with an Al2O3film having a thickness of 8 nm or greater (Tests 4 to 6) was not conductive. These results show that an Al2O3film having a thickness of 2 nm or greater prevents the conduction.

In contrast, the resistance of the laminate on which an Al2O3film having a thickness of 20 nm and an SiN layer of 620 nm were formed and which underwent the removal step (Test 7) was approximately the same as the resistance of Test 1. The SiN layer and the Al2O3film were removed in the removal step. Note that the laminate before the removal step was not conductive.

Next, further tests were conducted for investigation of the influence of the state of the adhesive tape on the removability.FIG. 10shows the results of the tests about the influence of the state of the adhesive tape on the removability. In the tests, a laminate was prepared by forming an ITO layer, an SiN layer, and an Al2O3film on a 100 mm square glass plate, and the SiN layer and the Al2O3layer were removed from the laminate by using adhesive tape. The removability of these layers was tested. An ACF was used as the adhesive tape. The adhesive tape was attached to the laminate under the conditions shown inFIG. 10by using the device for thermal compression bonding described above.

As shown inFIG. 10, when the ACF was hardened more than the case under the basic conditions (Test 8) by increasing the temperature for thermal compression bonding (Test 9), the ACF was slightly hard to remove, and residues of the ACF remained on the glass plate. However, there was almost no influence on the removability or the conductivity. The pressure was also increased (Test 10) or decreased (Test 11) to change the hardness of the ACF. However, there was no influence on the removability or the conductivity.

The hardness of the ACF is determined by the product of the temperature for thermal compression bonding and the duration of the thermal compression bonding. Under the conditions considering the hardness (i.e. the strength of the adhesion) of the ACF resin, the removability was excellent except for the case under a high temperature condition. Under a high temperature condition, there is a risk that the layers will be removed at the interface between the ACF and the atomic layer deposition film119aor at the interface between the TFT substrate111and the metal layer114a.

Finally, the case of using an ACF not containing conductive particles (Test 12) was compared with the case of using an ACF containing conductive particles (Test 8). There was no difference in the removability and the conductivity between them. This result shows that the excellent conductivity is due to the fact that the SiN layer and the Al2O3film were removed at the interface with the damaged layer, and is not due to the conductive particles causing cracks in the SiN layer and the Al2O3film and making them likely to be removed.

While a display panel manufacturing method, display apparatus manufacturing method, display panel and display apparatus according to aspects of the present invention have been concretely described, the above embodiment is merely an example for clearly illustrating the operations and advantageous effects of aspects of the present invention. The present invention is in no way limited to the above embodiment. For example, the following modifications can also be implemented.

FIGS. 11A through 11Gare an illustration of a method of manufacturing a display panel pertaining to Modification 2. According to the method of manufacturing a display panel pertaining to Modification 1, the protective film is not formed. This is the difference from the method of manufacturing a display panel pertaining to the embodiment described above, according to which the protective film is formed. The other features are basically the same as the method of manufacturing a display panel pertaining to the embodiment described above. The following only describes the difference in detail, and the explanations of the other features are omitted. In the following, same components as the components of the display panel pertaining to the above embodiment are given the same reference signs.

According to the method of manufacturing a display panel according to Modification 1, after the chemical vapor deposition layer118ais formed by the CVD method as shown inFIG. 4D, the atomic layer deposition film119ais not formed. The adhesive tape500is attached onto a portion of the chemical vapor deposition layer118a, the portion being located on the conductive layer114d, as shown inFIG. 11A. This completes the adhesive tape attaching step.

Next, by removing the adhesive tape500, the portion of the chemical vapor deposition layer118aon the conductive layer114dand the damaged layer114eof the conductive layer114dare removed together. As a result, a portion of the metal oxide layer114bis exposed. This completes the removal step of removing the portion of the chemical vapor deposition layer118aon the conductive layer114d.

The device substrate610is manufactured as described above.

Note that in the case of disposing the CF substrate, it is desirable that the step of disposing the CF substrate is performed after the step of forming the chemical vapor deposition layer as shown inFIG. 4Dand before the step of attaching the adhesive tape as shown inFIG. 11A.

As explained above, the atomic layer deposition film formation step is not essential for the method of manufacturing a display panel pertaining to the present disclosure.

FIGS. 12A through 12Gare an illustration of a method of manufacturing a display panel pertaining to Modification 2. According to the method of manufacturing a display panel pertaining to Modifications 2, the terminal part is formed from only a metal layer. This is the difference from the method of manufacturing a display panel pertaining to the above embodiment, according to which the terminal part is made up of a metal layer and a metal oxide layer. The other features are basically the same as the method of manufacturing a display panel pertaining to the embodiment described above. The following only describes the difference in detail, and the explanations of the other features are omitted. In the following, same components as the components of the display panel pertaining to the above embodiment are given the same reference signs.

According to the method of manufacturing a display panel pertaining to Modification 2, first, as shown inFIG. 12A, the terminal preparation area, where the terminal714is to be formed, is removed from the passivation film111don the TFT substrate111so that the metal layer714a, which is a portion of the SD wiring111c,is exposed. The metal layer714a, which is a portion of the SD wiring111con the TFT substrate111after removing the terminal preparation area, is also referred to as the conductive layer714a.

Next, as shown inFIG. 12B, the planarizing film112(having a thickness of 4 μm, for example) is formed by, for example, spin-coating a resin and patterning the resin by photoresist/photo etching. Furthermore, the bottom electrode713, for example, is formed from the metal layer. The bottom electrodes713are formed by the following steps, for example: first, a metal thin film is formed by vacuum vapor deposition or sputtering; and then the metal thin film is patterned by photoresist/photo etching.

Next, as shown inFIG. 12C, the bank115, the organic light-emitting layer116, the electron transport layer116X and the top electrode117are sequentially formed.

This completes the display part formation for forming the display part101on the TFT substrate111, and the conductive layer formation for forming the conductive layer714dmade of metal on the area on the TFT substrate111where the terminal714is to be formed.

Next, as shown inFIG. 12D, the chemical vapor deposition layer118amade of an inorganic compound is formed on the entire upper surface of the TFT substrate111by a plasma CVD method. In this process, the exposed portions of the conductive layer714a(i.e. the upper surface and the side surface of the conductive layer714a) alter. As a result, a damaged layer114bis formed on the surface of the conductive layer714a. This completes the chemical vapor deposition layer formation step of forming the chemical vapor deposition layer such that the chemical vapor deposition layer covers the display part and comes into contact at least with the upper surface of the conductive layer714aand the upper surface of the conductive layer714aalters. At this point, the conductive layer714ais composed of the damaged layer714band the terminal714made of metal underneath the damaged layer714b.

Next, as shown inFIG. 12E, an atomic layer deposition film119ais formed all over the upper surface of the TFT substrate111by an ALD method.

Next, as shown inFIG. 12F, the adhesive tape500is attached onto a portion of the atomic layer deposition film119a, the portion being located above the damaged layer714b(which is also above the conductive layer714d). This completes the adhesive tape attaching step.

Next, by removing the adhesive tape500, the portion of the atomic layer deposition film119aabove the conductive layer714a, the portion of the chemical vapor deposition layer118aon the conductive layer714a, and the damaged layer714bof the conductive layer714aare removed together as shown inFIG. 12G. As a result, the terminal714are exposed. This completes the removal step of removing the portion of the chemical vapor deposition layer118aon the conductive layer714a.

In the removal step, since the damaged layer714blies on the surface of the conductive layer714a, the chemical vapor deposition layer118aand the atomic layer deposition film119aare removed together with the adhesive tape500from the TFT substrate111. These layers are removed at the interface between the damaged layer714band the chemical vapor deposition layer118a, the interface between the damaged layer714band the terminal714, or at an area within the thickness of the damaged layer714b, because these areas are weak. The reason for the weakness of these areas is, for example, that the surface of the conductive layer714ais damaged by plasma used in the plasma CVD method.

The device substrate710is manufactured as described above.

In the manufacturing processes shown inFIGS. 12A through 12G, the step of disposing the CF substrate is omitted. In the case of disposing the CF substrate, it is desirable that the step of disposing the CF substrate is performed after the step of forming the atomic layer deposition film shown inFIG. 12Eand before the step of attaching the adhesive tape shown inFIG. 12F.

As described above, according to the method of manufacturing a display panel pertaining to the present disclosure, the conductive layer may be made from metal in the conductive layer formation step.

As another modification example, one or more layers may be formed on the atomic layer deposition film. Also in this case, the portions on the conductive layer can be removed by performing the removal step. The method of removing the chemical vapor deposition layer is not limited to the method using the adhesive tape. For example, the layer may be removed by a method using laser.

INDUSTRIAL APPLICABILITY

A display panel and display apparatus according to an aspect of the present disclosure may be favorably used in the home, in public facilities, and in the workplace in various display apparatuses, televisions, displays for portable electronic devices, and the like.

REFERENCE SIGNS LIST