JP4574039B2 - Method for manufacturing EL display device - Google Patents

Description

【０２５４】
(M.A.Baldo, D.F.O'Brien, Y.You, A.Shoustikov, S.Sibley, M.E.Thompson, S.R.Forrest, Nature 395 (1998) p.151.)
【０２５５】
上記の論文により報告されたＥＬ材料（Ｐｔ錯体）の分子式を以下に示す。
【０２５６】
【化２】

【０２５７】
(M.A.Baldo, S.Lamansky, P.E.Burrrows, M.E.Thompson, S.R.Forrest, Appl.Phys.Lett.,75 (1999) p.4.) (T.Tsutsui, M.-J.Yang, M.Yahiro, K.Nakamura, T.Watanabe, T.tsuji, Y.Fukuda, T.Wakimoto, S.Mayaguchi, Jpn.Appl.Phys., 38 (12B) (1999) L1502.)
【０２５８】
上記の論文により報告されたＥＬ材料（Ｉｒ錯体）の分子式を以下に示す。
【０２５９】
【化３】

【０２６０】
以上のように三重項励起子からの燐光発光を利用できれば原理的には一重項励起子からの蛍光発光を用いる場合より３〜４倍の高い外部発光量子効率の実現が可能となる。
【０２６１】
なお、本実施例の構成は、実施例１〜実施例９のいずれの構成とも自由に組み合わせて実施することが可能である。
【０２６２】
【発明の効果】
本発明を実施することで、マスクを通して被形成面に蒸着法でＥＬ材料を成膜させる際、ＥＬ材料がマスクを通過できずにマスク上に蒸着されるという事態を防ぐことができる。さらに、本発明では、複数のマスクを用いて成膜位置の位置あわせ精度を向上させることができる。
【０２６３】
また、電気的な反発により、マスク上にＥＬ材料が蒸着されることを防ぐことができるのでマスクを何度も使用することができ、かつ位置あわせ精度の問題なく精密にＥＬ材料を成膜することができるため、ＥＬ材料を用いたＥＬ表示装置の製造歩留まりを向上させたり、低コスト化をはかることができる。さらに、蒸着直前に蒸気状態のＥＬ材料の蒸着位置を制御するため、これまでの蒸着方法を用いることができ、幅広い応用が可能である。
【図面の簡単な説明】
【図１】本発明の有機ＥＬ材料の蒸着方法を示す図。
【図２】画素部の断面構造を示す図。
【図３】画素部の上面構造及び構成を示す図。
【図４】ＥＬ表示装置の作製工程を示す図。
【図５】ＥＬ表示装置の作製工程を示す図。
【図６】ＥＬ表示装置の作製工程を示す図。
【図７】ＥＬ表示装置の画素部のＴＦＴの断面構造を示す図。
【図８】ＥＬ表示装置の画素部のＴＦＴの断面構造を示す図。
【図９】ＥＬ表示装置の外観を示す図。
【図１０】ＥＬ表示装置の回路ブロック構成を示す図。
【図１１】アクティブマトリクス型のＥＬ表示装置の断面構造を示す図。
【図１２】有機ＥＬ材料の蒸着パターンを示す図。
【図１３】マスクパターンを示す図。
【図１４】パッシブ型のＥＬ表示装置の断面構造を示す図。
【図１５】電気器具の具体例を示す図。
【図１６】電気器具の具体例を示す図。
【図１７】本発明の有機ＥＬ材料の蒸着方法を示す図。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a self-luminous device in which an EL element having a structure in which an anode, a cathode, and a light-emitting organic material (hereinafter referred to as organic EL material) from which EL (Electro Luminescence) is sandwiched is formed on an insulator. The present invention also relates to an electric appliance having the light-emitting device as a display unit (display display or display monitor), and a thin film forming method and a thin film forming apparatus for organic EL material. The self-luminous device is also referred to as OLED (Organic Light Emitting Diodes).
[0002]
[Prior art]
2. Description of the Related Art In recent years, self-light-emitting devices (EL display devices) using EL elements as self-light-emitting elements using the EL phenomenon of light-emitting organic materials have been developed. Since the EL display device is a self-luminous type, it does not require a backlight like a liquid crystal display device, and has a wide viewing angle, and thus is promising as a display unit of an electric appliance.
[0003]
There are two types of EL display devices, a passive type (simple matrix type) and an active type (active matrix type), both of which are actively developed. In particular, active matrix EL display devices are currently attracting attention. In addition, low molecular organic EL materials and high molecular (polymer) organic EL materials have been studied as EL materials that serve as an EL layer that can be said to be the center of an EL element.
[0004]
There are methods such as an inkjet method, a vapor deposition method, and a spin coating method as a method for forming an EL material, and among these methods, the vapor deposition method employs a method of controlling a film formation position using a mask. At this time, there is a problem that the EL material is deposited on the mask without passing through the mask.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and an object of the present invention is to provide means for selectively forming an EL material without waste by an evaporation method in which the EL material is subjected to electric field control using a mask. Another object is to increase the control accuracy of the film forming position. It is another object of the present invention to provide an EL display device using such means and a manufacturing method thereof. And it makes it a subject to provide the electric appliance which has such an EL display device as a display part.
[0006]
[Means for Solving the Problems]
A voltage is applied to the mask used to achieve the above object and the pixel electrode to be formed.
[0007]
In the present invention, the EL material is provided in the sample boat, and when it is vaporized and has further electric charge, it is generated by the voltage applied to the mask before it reaches the substrate by jumping out from the opening of the sample boat due to vaporization. The traveling direction is controlled by the electric field, and the deposition position can be controlled.
[0008]
A plurality of masks may be used. For example, the traveling direction is controlled by the electric field generated by the voltage applied to each of the first mask and the second mask, and the deposition position can be controlled.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Here, an embodiment of the present invention will be described with reference to FIG.
[0010]
FIG. 1A is a diagram schematically showing a state in which an EL material is formed by implementing the present invention. In FIG. 1A, reference numeral 110 denotes a substrate, and a pixel electrode on the substrate is connected to a ground potential. Reference numeral 111 denotes a sample boat. The sample boat 111 is provided with an EL material.
[0011]
When the red EL layer is formed, the sample boat 111 has an EL material that emits red light (hereinafter referred to as a red EL material). When the green EL layer is formed, the sample boat 111 has an EL material that emits green light ( Hereinafter, when forming a blue EL layer, the sample boat 111 is provided with an EL material that emits blue light (hereinafter referred to as a blue EL material).
[0012]
In the case of the present invention, the EL material of the sample boat 111 is vaporized and released by resistance heating by the electrode 120. When released, the EL material becomes negatively charged particles by a negative voltage applied to the electrode 112, passes through the gap of the mask 113 made of a conductive material, and is deposited on the pixel electrode on the substrate 110. In addition, an insulator is provided between the electrode 112 and the electrode 120, and different voltages are applied thereto.
[0013]
Note that when the EL material passes through the mask 113, the traveling direction is controlled by the blocking portion 118 in the mask 113 as shown in the enlarged view of FIG. The mask 113 has a portion of the blocking portion 118 in which a plurality of conductive lines made of a conductive material such as copper, iron, aluminum, tantalum, titanium, and tungsten are arranged in parallel to each other (stripe shape), or A mesh-like structure (mesh shape) or a plate-like structure. Since the EL material in a vapor state repels an electric field generated by a negative voltage applied to the blocking portion 118, the EL material passes through the gap between the blocking portions 118 and is deposited on the substrate.
[0014]
Moreover, although the example whose cross-sectional shape is circular was shown in FIG. 1, it does not specifically limit, A rectangle, an ellipse, or a polygon may be sufficient.
[0015]
Note that a voltage is applied to the blocking portion 118 of the mask 113 so that the vaporized EL material can repel the blocking portion 118 of the mask 113. Thereby, the EL material can pass through the gap between the blocking portions 118 in the mask 113. Note that here, the EL material in a vapor state is charged by an electric field generated by the electrode 112 to which a negative voltage is applied, and an electric field is generated by applying a negative voltage to the blocking portion of the mask by the electrode 115. As a result, the charged particles of the EL material in the vapor state are electrically repelled from the blocking portions and pass through the gaps between the blocking portions.
[0016]
With the structure shown in FIG. 1A, the deposition position can be controlled with high accuracy by appropriately adjusting the negative voltage applied to the blocking portion 118 within a range of several tens of volts to 10 kV.
[0017]
The practitioner may set the distance between the mask 113 and the substrate, the distance between the blocking portions 118, and the like as appropriate. For example, the distance between the blocking portions 118 may be the pixel pitch of the pixel electrodes formed on the substrate.
[0018]
In order to make the alignment of the mask 113 accurate, the mask 113 may be formed by stacking two conductive plates and simultaneously cutting a slit-like or circular hole by electric discharge machining.
[0019]
Although an example using one mask is shown here, a voltage may be applied to two or more masks to control the flight direction of the EL material in the vapor state. Further, the flight direction of the EL material in the vapor state may be controlled by applying a voltage to a combination of two or more masks on a certain plane.
[0020]
First, the sample boat 111 is provided with a red EL material, and when this is deposited, a striped red EL layer is formed on the pixel.
[0021]
Next, after moving the mask by one pixel column in the direction of arrow k, a green EL material is deposited from the sample boat 111 to form a green EL layer. Further, the mask is moved by one pixel column in the direction of the arrow k, and vapor deposition is similarly performed to form a blue EL layer.
[0022]
That is, by moving the mask in the direction of the arrow k and evaporating the pixel rows emitting red, green, and blue in three portions for each color, a three-color striped EL layer is formed. Note that the thickness of the EL layer formed here is desirably 10 nm to 10 μm.
[0023]
The pixel column here refers to a column of pixels partitioned by a bank 119, and the bank is formed above the source wiring of the pixel column in a bank shape so as to fill a gap between the pixel columns. That is, since the pixel columns are partitioned by the banks, the EL layer formed on the pixels can be formed separately from the adjacent pixel columns. That is, a column in which a plurality of pixels are arranged in series along the source wiring is called a pixel column. Although the case where the bank is formed above the source wiring has been described here, it may be provided above the gate wiring. In this case, a column in which a plurality of pixels are arranged in series along the gate wiring is called a pixel column.
[0024]
Accordingly, a pixel portion (not shown) on the pixel electrode can be viewed as an aggregate of a plurality of pixel columns divided by a stripe bank provided above the plurality of source lines or the plurality of gate lines. . When viewed in such a manner, the pixel portion on the pixel electrode has a pixel column in which a striped EL layer emitting red light is formed, a pixel column in which a stripe EL layer emitting green light is formed, and a blue color It can also be said that the pixel array is formed with a stripe EL layer that emits light.
[0025]
In addition, since the stripe-shaped bank is provided above the plurality of source wirings or the plurality of gate wirings, the pixel portion substantially includes a plurality of pixels divided by the plurality of source wirings or the plurality of gate wirings. It can also be viewed as a collection of columns.
[0026]
Further, in this embodiment mode, a voltage is applied to the pixel electrode (anode) formed on the substrate 110 and the vaporized EL material that has passed through the mask is further controlled to be selectively placed at a desired position. It is preferable to give an electric field for vapor deposition.
[0027]
Further, a negatively charged vaporized EL material is applied to the inner side surface of the vapor deposition chamber 121 provided with the sample boat 111, the mask, and the substrate 110 by the electrode 114, and the inner side surface of the vapor deposition chamber. Therefore, the vaporized EL material can be deposited on the surface to be formed without adhering to the inside of the deposition chamber.
[0028]
【Example】
[Example 1]
In this embodiment, a method for forming a film on a substrate by controlling an EL material vaporized in a sample boat (hereinafter referred to as an EL material in a vapor state) with an electric field will be described. In addition, FIG. 1 is used for the vapor deposition method in a present Example.
[0029]
In FIG. 1, 110 is a substrate and 111 is a sample boat. The sample boat 111 is provided with an EL layer material.
[0030]
When the red EL layer is formed, the sample boat 111 has an EL material that emits red light (hereinafter referred to as a red EL material). When the green EL layer is formed, the sample boat 111 has an EL material that emits green light ( Hereinafter, when forming a blue EL layer, the sample boat 111 is provided with an EL material that emits blue light (hereinafter referred to as a blue EL material).
[0031]
In this example, as the EL material, a red EL layer doped with red fluorescent dye DCM using Alq as a host material was used. Further, Alq which is an 8-hydroxyquinoline complex of aluminum is used for an EL layer emitting green light, and a zinc benzoxazole complex (Zn (oxz)) is used for an EL layer emitting blue light. ₂ ) Is used.
[0032]
Note that the above-described EL material is one of the examples, and other known EL materials may be used. Further, although the EL materials are selected with the emission colors of red, green, and blue, the present invention is not limited to this, and colors such as yellow, orange, and gray may be used.
[0033]
In this embodiment, a sample boat is first provided with a red EL material, a red EL layer is formed on the substrate, and then a green EL layer is formed on the substrate using the sample boat provided with the green EL material. . Finally, a blue EL layer is formed on the substrate using a sample boat provided with a blue EL material.
[0034]
As described above, the EL layer can be formed by evaporating the red, green, and blue EL materials in three portions.
[0035]
Each color EL material is vaporized by resistance heating by the electrode 120 in the sample boat, and has an electric charge due to the electric field applied by the electrode 112 when emitted from the sample boat 111. At this time, the EL material jumps out with higher kinetic energy obtained by vaporization and reaches the mask 113.
[0036]
Since a voltage is applied to the mask 113, an electric field is generated in the vicinity of the mask 113. The material for the gas EL layer that has reached the mask 113 is controlled by the electric field generated by the mask 113, passes through the mask 113, and is deposited on the substrate 110.
[0037]
Further, when the red EL material of the sample boat 111 is deposited, a striped red EL layer is formed on the pixel. Here, the mask is moved by one column in the direction of the arrow k, and the green EL material is similarly deposited from the sample boat 111. Thereby, a green EL layer is formed beside the red EL layer. Further, the blue EL material is deposited from the sample boat 111 while moving the mask by one column in the direction of the arrow k. Thereby, a blue EL layer is formed beside the green EL layer. That is, by moving the pixel row emitting red, green, and blue in three times for each color while evaporating the mask as described above, a three-color striped EL layer is formed. Note that the thickness of the EL layer formed here is desirably 100 nm to 1 μm.
[0038]
Note that the pixel column here refers to a column of pixels partitioned by a bank 119, and the bank is formed above the source wiring. That is, a column in which a plurality of pixels are arranged in series along the source wiring is called a pixel column. Although the case where the bank is formed above the source wiring has been described here, it may be provided above the gate wiring. In this case, a column in which a plurality of pixels are arranged in series along the gate wiring is called a pixel column.
[0039]
Accordingly, the pixel portion (not shown) can be viewed as an aggregate of a plurality of pixel columns divided by a stripe bank provided above the plurality of source lines or the plurality of gate lines. When viewed in this manner, the pixel portion includes a pixel column in which a stripe-shaped EL layer that emits red light is formed, a pixel column in which a stripe-shaped EL layer that emits green light is formed, and a stripe shape that emits blue light. It can also be said that it consists of a pixel column in which the EL layer is formed.
[0040]
In addition, since the stripe-shaped bank is provided above the plurality of source wirings or the plurality of gate wirings, the pixel portion substantially includes a plurality of pixels divided by the plurality of source wirings or the plurality of gate wirings. It can also be viewed as a collection of columns.
[0041]
In addition, an electric field is applied such that a voltage is applied to the pixel electrode (anode) formed on the substrate 110 and the vaporized EL material that has passed through the mask is further controlled to be selectively deposited at a desired position. It is good to give.
[0042]
[Example 2]
2 is a cross-sectional view of a pixel portion of an EL display device according to this embodiment, FIG. 3A is a top view thereof, and FIG. 3B is a circuit configuration thereof. Actually, a plurality of pixels are arranged in a matrix to form a pixel portion (image display portion). Note that a cross-sectional view taken along line AA ′ in FIG. 3A corresponds to FIG. Accordingly, since the same reference numerals are used in FIG. 2 and FIG. 3, both drawings should be referred to as appropriate. In the top view of FIG. 3A, two pixels are illustrated, but both have the same structure.
[0043]
In FIG. 2, 11 is a substrate, and 12 is an insulating film (hereinafter referred to as a base film) serving as a base. As the substrate 11, a substrate made of glass, glass ceramics, quartz, silicon, ceramics, metal, or plastic can be used.
[0044]
The base film 12 is particularly effective when a substrate containing mobile ions or a conductive substrate is used, but it need not be provided on the quartz substrate. As the base film 12, an insulating film containing silicon may be used. Note that in this specification, the “insulating film containing silicon” specifically includes silicon, oxygen, or nitrogen such as a silicon oxide film, a silicon nitride film, or a silicon nitride oxide film (indicated by SiOxNy) at a predetermined ratio. An insulating film.
[0045]
In addition, it is effective to dissipate the heat generated by the TFT by providing the base film 12 with a heat dissipation effect in order to prevent the deterioration of the TFT or the EL element. Any known material can be used to provide a heat dissipation effect.
[0046]
Here, two TFTs are formed in the pixel. Reference numeral 201 denotes a switching TFT, which is an n-channel TFT, and 202 is a current control TFT, which is a p-channel TFT.
[0047]
However, in this embodiment, it is not necessary to limit the switching TFT to an n-channel TFT and the current control TFT to a p-channel TFT. The switching TFT is a p-channel TFT and the current control TFT is an n-channel TFT. It is also possible to use n-channel or p-channel TFTs for both.
[0048]
The switching TFT 201 includes a source region 13, a drain region 14, LDD regions 15a to 15d, an active layer including a high concentration impurity region 16 and channel forming regions 17a and 17b, a gate insulating film 18, gate electrodes 19a and 19b, and a first interlayer. An insulating film 20, a source wiring 21, and a drain wiring 22 are formed.
[0049]
Further, as shown in FIG. 3, the gate electrodes 19a and 19b have a double gate structure in which the gate electrodes 19a and 19b are electrically connected by a gate wiring 211 formed of another material (a material having a lower resistance than the gate electrodes 19a and 19b). ing. Needless to say, not only a double gate structure but also a so-called multigate structure (a structure including an active layer having two or more channel formation regions connected in series) such as a single gate structure or a triple gate structure may be used. The multi-gate structure is extremely effective in reducing the off-current value. Here, the switching element 201 of the pixel has a multi-gate structure to realize a switching element with a low off-current value.
[0050]
The active layer is formed of a semiconductor film including a crystal structure. That is, a single crystal semiconductor film, a polycrystalline semiconductor film, or a microcrystalline semiconductor film may be used. The gate insulating film 18 may be formed of an insulating film containing silicon. Any conductive film can be used for the gate electrode, the source wiring, or the drain wiring.
[0051]
Further, in the switching TFT 201, the LDD regions 15a to 15d are provided so as not to overlap the gate electrodes 19a and 19b with the gate insulating film 18 interposed therebetween. Such a structure is very effective in reducing the off-current value.
[0052]
Note that it is more preferable to provide an offset region (a region made of a semiconductor layer having the same composition as the channel formation region to which no gate voltage is applied) between the channel formation region and the LDD region in order to reduce the off-state current value. In the case of a multi-gate structure having two or more gate electrodes, a high-concentration impurity region provided between channel formation regions is effective in reducing the off-current value.
[0053]
Next, the current control TFT 202 includes an active layer including the source region 31, the drain region 32, and the channel formation region 34, the gate insulating film 18, the gate electrode 35, the first interlayer insulating film 20, the source wiring 36, and the drain wiring 37. Formed. The gate electrode 35 has a single gate structure, but may have a multi-gate structure.
[0054]
As shown in FIG. 2, the drain of the switching TFT is connected to the gate of the current control TFT 202. Specifically, the gate electrode 35 of the current control TFT 202 is electrically connected to the drain region 14 of the switching TFT 201 via the drain wiring (also referred to as connection wiring) 22. The source wiring 36 is formed connected to the power supply line 212 or formed as a part of the current supply line.
[0055]
The current control TFT 202 is an element for controlling the amount of current injected into the EL element 203, but it is not preferable to flow a large amount of current in consideration of deterioration of the EL element. Therefore, it is preferable to design the channel length (L) to be long so that an excessive current does not flow through the current control TFT 202. Desirably, it is set to 0.5 to 2 μA (preferably 1 to 1.5 μA) per pixel.
[0056]
The length (width) of the LDD region formed in the switching TFT 201 may be 0.5 to 3.5 μm, typically 2.0 to 2.5 μm.
[0057]
Also, as shown in FIG. 3, the wiring 36 including the gate electrode 35 of the current control TFT 202 overlaps the power supply line 212 of the current control TFT 202 in the region indicated by 50 with an insulating film interposed therebetween. At this time, in a region indicated by 50, a storage capacitor (capacitor) is formed. As the storage capacitor 50, a semiconductor film 51 electrically connected to the power supply line 212, an insulating film (not shown) in the same layer as the gate insulating film, and a capacitor formed by the power supply line 212 are also used as the storage capacitor. Is possible.
[0058]
The holding capacitor 50 functions as a capacitor for holding a voltage applied to the gate electrode 35 of the current control TFT 202.
[0059]
Further, from the viewpoint of increasing the amount of current that can be passed, the thickness of the active layer (especially the channel formation region) of the current control TFT 202 may be increased (preferably 50 to 100 nm, more preferably 60 to 80 nm). It is valid. Conversely, in the case of the switching TFT 201, from the viewpoint of reducing the off-current value, the thickness of the active layer (especially the channel formation region) should be reduced (preferably 20 to 50 nm, more preferably 25 to 40 nm). Is also effective.
[0060]
Next, reference numeral 38 denotes a first passivation film, and the film thickness may be 10 nm to 10 μm (preferably 200 to 500 nm). As a material, an insulating film containing silicon (in particular, a silicon nitride oxide film or a silicon nitride film is preferable) can be used.
[0061]
On the first passivation film 38, a second interlayer insulating film (which may be referred to as a flattening film) 39 is formed so as to cover each TFT, and a step formed by the TFT is flattened. The second interlayer insulating film 39 is preferably an organic resin film, and polyimide, polyamide, acrylic resin, BCB (benzocyclobutene), or the like may be used. Of course, an inorganic film may be used if sufficient planarization is possible.
[0062]
It is very important to flatten the step due to the TFT by the second interlayer insulating film 39. Since an EL layer to be formed later is very thin, a light emission defect may occur due to the presence of a step. Therefore, it is desirable to planarize the pixel electrode before forming the pixel electrode so that the EL layer can be formed as flat as possible.
[0063]
Reference numeral 40 denotes a pixel electrode (corresponding to an anode of an EL element) made of a transparent conductive film, which is formed after opening a contact hole (opening) in the second interlayer insulating film 39 and the first passivation film 38. The opening is formed so as to be connected to the drain wiring 37 of the current control TFT 202.
[0064]
In this embodiment, a conductive film made of a compound of indium oxide and tin oxide is used as the pixel electrode. Further, a small amount of gallium may be added thereto. Further, a compound of indium oxide and zinc oxide or a compound of zinc oxide and gallium oxide can be used.
[0065]
After the pixel electrode is formed, a bank made of a resin material is formed. The bank is formed by patterning using an organic resin film and a resist material having different selectivity to the etching material of the bank a (41a) and the bank b (41b). Here, the bank a (41a) and the bank b (41b) are stacked and then etched, and a shape as shown in FIG. 2 can be formed depending on the etching rate. Note that the etching rate at this time is set so that the relationship (resin forming bank a)> (resin forming bank b) is established. The bank a (41a) and the bank b (41b) are formed in stripes between the pixels as shown in FIG. 3C. Note that h1 in FIG. 3C is preferably 0.5 to 3 μm, and is preferably larger than the film thickness in which the EL layer, the cathode, and the protective electrode are stacked. In this embodiment, it is formed along the source wiring 21 but may be formed along the gate wiring 35.
[0066]
Next, the EL layer 42 is formed by the thin film forming method described with reference to FIG. Although only one pixel is shown here, EL layers corresponding to each color of R (red), G (green), and B (blue) are formed as described in FIG.
[0067]
First, the EL material provided in the sample boat 111 is vaporized (evaporated) by resistance heating by the electrode 120. At the moment when the vaporized EL material jumps out of the sample boat 111, the vaporized EL material is charged by the influence of the electric field by the electrode 112 attached to the opening of the sample boat 111 to become charged particles. The traveling direction of the charged particles is controlled by an electric field in the vicinity of the mask that is generated when a voltage is applied to the blocking portion 118 when passing through the mask 113.
[0068]
Note that an electric field may be generated by providing an electrode between the sample boat and the mask, and the electric charge of the vaporized EL material discharged from the sample boat may be controlled.
[0069]
As a result, the gas EL material passes through the gaps between the blocking portions and is deposited on the surface to be formed on the substrate.
[0070]
Note that the mask blocking portion in this specification refers to a portion of the mask formed of a conductive material, and the conductive material refers to a material such as titanium, tantalum, tungsten, and aluminum. . Moreover, the opening part of the mask points out the clearance gap between each interruption | blocking part.
[0071]
Further, in the present specification, the surface to be formed is a part of the surface of the pixel electrode or the organic film and means a surface on which a thin film is to be formed.
[0072]
Further, it is sufficient that a voltage of several tens of V to 10 kV is applied to the mask, and preferably, a voltage of 10 V to 1 kV is applied. Moreover, the practitioner may set a voltage within these ranges as appropriate for each electrode.
[0073]
In the present embodiment, first, a red EL material provided in the sample boat 111 is vaporized (evaporated) and vapor-deposited to form a pixel row emitting red light on the pixel. Next, after moving the mask in the horizontal direction (in the direction of the arrow k), the green EL material provided in the sample boat 111 is vapor-deposited to form a pixel row that should emit green light.
Further, the mask is moved in the horizontal direction (in the direction of the arrow k) to deposit the blue EL material provided in the sample boat 111 to form a pixel row that should emit blue light.
[0074]
Note that the sample boat 111 provided with the EL material may be changed together every time the type of the EL material is changed, or only the EL material may be replaced and used without changing the sample boat.
[0075]
In addition, the sample boat 111 and the mask described here may be provided separately, but may be integrally formed as an apparatus.
[0076]
As described above, the pixel array that emits red, green, and blue light is vapor-deposited three times for each color while the mask is moved to form a three-color stripe-shaped EL layer.
[0077]
A low molecular material may be used as the EL material for the EL layer. Typical low molecular weight materials include EL materials such as tris (8-quinolinonato) aluminum complex (Alq) and bis (benzoquinolinolato) beryllium complex (BeBq).
[0078]
In this example, as the EL material, a red EL layer doped with red fluorescent dye DCM using Alq as a host material was used. Further, Alq which is an 8-hydroxyquinoline complex of aluminum is used for an EL layer emitting green light, and a zinc benzoxazole complex (Zn (oxz)) is used for an EL layer emitting blue light. ₂ ) Is used.
[0079]
However, the above example is an example of an EL material that can be used as the EL layer of this embodiment, and is not necessarily limited to this.
[0080]
In other words, a polymer organic EL material not described here may be used by a coating method or may be formed together with a polymer material.
[0081]
Further, when the EL layer 42 is formed, the EL layer easily deteriorates due to the presence of moisture and oxygen, so that the treatment atmosphere is an atmosphere with little moisture and oxygen and is performed in an inert gas such as nitrogen or argon. desirable.
[0082]
After the EL layer 42 is formed as described above, a cathode 43 made of a light-shielding conductive film, a protective electrode 44, and a second passivation film 45 are formed next. In this embodiment, a conductive film made of MgAg is used as the cathode 43, and a conductive film made of aluminum is used as the protective electrode 44. The second passivation film 45 is a silicon nitride film having a thickness of 10 nm to 10 μm (preferably 200 to 500 nm).
[0083]
Since the EL layer is vulnerable to heat as described above, it is desirable that the cathode 43 and the second passivation film 45 be formed at as low a temperature as possible (preferably in a temperature range from room temperature to 120 ° C.). Therefore, it can be said that a plasma CVD method, a vacuum deposition method, or a solution coating method (spin coating method) is a desirable film forming method.
[0084]
The completed substrate is called an active matrix substrate, and a counter substrate (not shown) is provided so as to face the active matrix substrate. In this embodiment, a glass substrate is used as the counter substrate. As the counter substrate, a substrate made of plastic or ceramics may be used.
[0085]
Further, the active matrix substrate and the counter substrate are bonded with a sealant (not shown) to form a sealed space (not shown). In this embodiment, the sealed space is filled with argon gas. Of course, it is possible to arrange a desiccant such as barium oxide or an antioxidant in the sealed space.
[0086]
Further, the configuration of the present embodiment can be freely combined with the configuration of the first embodiment.
[0087]
Example 3
Here, a method for forming a bank including the bank a and the bank b shown in FIG. 3C will be described. Both the bank a and the bank b are positive type.
[0088]
First, after the pixel electrode is formed, an organic resin film made of melamine resin is formed. This later forms bank a. The melamine resin is mixed with a dye to have a function as an antireflection film. These may be used by dissolving in a solvent such as dimethylacetamide. In selecting a dye, it is necessary to select a dye having an emission spectrum at a position close to the spectrum of light used for exposure.
[0089]
Next, polyimide is laminated on the melamine resin. Here, photosensitive polyimide may be used instead of polyimide, or novolac resin may be used.
This later forms bank b.
[0090]
Here, a two-layer organic resin film is formed. This is exposed and patterned. As the developer for patterning, a water-soluble developer may be used. In this embodiment, tetramethylammonium hydroxide is preferably used. This is suitable for this embodiment because it is water-soluble and alkaline. However, the developer is not limited to this, and a known developer may be used.
[0091]
By developing with the developing solution, the bank a and the bank b have the shapes as shown in FIG. This is because the exposure intensity is changed by mixing the dye in the bank a and is etched isotropically with the developer. In addition, as for h2 shown here, it is desirable that it is 0.5-3 micrometers.
[0092]
Note that the bank a and the bank b are not necessarily limited to the laminated structure of the organic resin film as described above. After the bank a is formed of an inorganic film such as silicon oxide or silicon nitride, the bank b is changed to polyimide or Alternatively, an organic resin film such as polyamide or photosensitive resin may be used, or these materials used for the bank a and the bank b may be used in reverse.
[0093]
Moreover, the structure of a present Example can be freely combined with the structure of Example 1-2.
[0094]
Example 4
A method for simultaneously manufacturing a pixel portion and a TFT of a driver circuit portion provided around the pixel portion in the present invention will be described with reference to FIGS. However, in order to simplify the description, a CMOS circuit, which is a basic circuit, is illustrated with respect to the drive circuit.
[0095]
First, as shown in FIG. 4A, a base film 301 is formed to a thickness of 300 nm over a glass substrate 300. In this embodiment, a 100 nm thick silicon nitride oxide film and a 200 nm silicon nitride oxide film are stacked as the base film 301. At this time, the nitrogen concentration in contact with the glass substrate 300 is preferably set to 10 to 25 wt%. Of course, the element may be formed directly on the quartz substrate without providing a base film.
[0096]
Next, an amorphous silicon film (not shown) having a thickness of 50 nm is formed on the base film 301 by a known film formation method. Note that the semiconductor film is not limited to an amorphous silicon film, and any semiconductor film including an amorphous structure (including a microcrystalline semiconductor film) may be used. Further, a compound semiconductor film including an amorphous structure such as an amorphous silicon germanium film may be used. The film thickness may be 20 to 100 nm.
[0097]
Then, the amorphous silicon film is crystallized by a known technique to form a crystalline silicon film (also referred to as a polycrystalline silicon film or a polysilicon film) 302. Known crystallization methods include a thermal crystallization method using an electric furnace, a laser annealing crystallization method using laser light, and a lamp annealing crystallization method using infrared light. In this embodiment, crystallization is performed using excimer laser light using XeCl gas.
[0098]
In this embodiment, a pulse oscillation type excimer laser beam processed into a linear shape is used. However, a rectangular shape, a continuous oscillation type argon laser beam, or a continuous oscillation type excimer laser beam may be used. .
[0099]
In this embodiment, a crystalline silicon film is used as an active layer of a TFT, but an amorphous silicon film can also be used. It is also possible to form the active layer of the switching TFT that needs to reduce the off-current with an amorphous silicon film and form the active layer of the current control TFT with a crystalline silicon film. Since the amorphous silicon film has low carrier mobility, it is difficult for an electric current to flow and an off current is difficult to flow. That is, the advantages of both an amorphous silicon film that hardly allows current to flow and a crystalline silicon film that easily allows current to flow can be utilized.
[0100]
Next, as shown in FIG. 4B, a protective film 303 made of a silicon oxide film is formed on the crystalline silicon film 302 to a thickness of 130 nm. This thickness may be selected in the range of 100 to 200 nm (preferably 130 to 170 nm). Any other film may be used as long as it is an insulating film containing silicon. This protective film 303 is provided in order to prevent the crystalline silicon film from being directly exposed to plasma when an impurity is added and to enable fine concentration control.
[0101]
Then, resist masks 304 a and 304 b are formed thereon, and an impurity element imparting n-type (hereinafter referred to as an n-type impurity element) is added through the protective film 303.
Note that as the n-type impurity element, an element typically belonging to Group 15, typically phosphorus or arsenic can be used. In this example, phosphine (PH _Three ) Using a plasma (ion) doping method in which plasma is excited without mass separation, and phosphorus is 1 × 10 ¹⁸ atoms / cm ^Three Add at a concentration of Of course, an ion implantation method for performing mass separation may be used.
[0102]
In the n-type impurity region 305 formed by this process, an n-type impurity element contains 2 × 10 6. ¹⁶ ~ 5x10 ¹⁹ atoms / cm ^Three (Typically 5 × 10 ¹⁷ ~ 5x10 ¹⁸ atoms / cm ^Three ) Adjust the dose so that it is included at the concentration of
[0103]
Next, as shown in FIG. 4C, the protective film 303 and the resists 304a and 304b are removed, and the added elements belonging to Group 15 are activated. As the activation means, a known technique may be used. In this embodiment, activation is performed by irradiation with excimer laser light. Of course, the pulse oscillation type or the continuous oscillation type may be used, and it is not necessary to limit to the excimer laser beam. However, since the purpose is to activate the added impurity element, it is preferable to irradiate with energy that does not melt the crystalline silicon film. Note that laser light may be irradiated with the protective film 303 attached.
[0104]
Note that activation by heat treatment may be used in combination with the activation of the impurity element by the laser beam. When activation by heat treatment is performed, heat treatment at about 450 to 550 ° C. may be performed in consideration of the heat resistance of the substrate.
[0105]
By this step, an end portion of the n-type impurity region 305, that is, a boundary portion (junction portion) between the n-type impurity region 305 and a region not added with the n-type impurity element is clarified. This means that when the TFT is later completed, the LDD region and the channel formation region can form a very good junction.
[0106]
Next, as shown in FIG. 4D, unnecessary portions of the crystalline silicon film are removed, and island-shaped semiconductor films (hereinafter referred to as active layers) 306 to 309 are formed.
[0107]
Next, as shown in FIG. 4E, a gate insulating film 310 is formed so as to cover the active layers 306 to 309. As the gate insulating film 310, an insulating film containing silicon with a thickness of 10 to 200 nm, preferably 50 to 150 nm may be used. This may be a single layer structure or a laminated structure. In this embodiment, a silicon nitride oxide film having a thickness of 110 nm is used.
[0108]
Next, a conductive film having a thickness of 200 to 400 nm is formed and patterned to form gate electrodes 311 to 315. The ends of the gate electrodes 311 to 315 can be tapered. Note that in this embodiment, the gate electrode and a wiring (hereinafter referred to as a gate wiring) electrically connected to the gate electrode are formed using different materials. Specifically, a material having a resistance lower than that of the gate electrode is used for the gate wiring.
This is because a material that can be finely processed is used for the gate electrode, and a material that has a low wiring resistance is used for the gate wiring even though it cannot be finely processed. Of course, the gate electrode and the gate wiring may be formed of the same material.
[0109]
The gate electrode may be formed of a single-layer conductive film, but it is preferable to form a stacked film of two layers or three layers as necessary. Any known conductive film can be used as the material of the gate electrode. However, a material that can be finely processed as described above, specifically, that can be patterned to a line width of 2 μm or less is preferable.
[0110]
Typically, a film made of an element selected from tantalum (Ta), titanium (Ti), molybdenum (Mo), tungsten (W), chromium (Cr), and silicon (Si), or a nitride film of the element (Typically tantalum nitride film, tungsten nitride film, titanium nitride film), an alloy film (typically Mo—W alloy, Mo—Ta alloy), or a silicide film of the above elements (typical) Specifically, a tungsten silicide film or a titanium silicide film) can be used. Of course, it may be used as a single layer or may be laminated.
[0111]
In this embodiment, a laminated film including a tantalum nitride (TaN) film having a thickness of 50 nm and a tantalum (Ta) film having a thickness of 350 nm is used. This may be formed by sputtering. Further, when an inert gas such as Xe or Ne is added as a sputtering gas, peeling of the film due to stress can be prevented.
[0112]
At this time, the gate electrode 312 is formed so as to overlap a part of the n-type impurity region 305 with the gate insulating film 310 interposed therebetween. This overlapped portion later becomes an LDD region overlapping with the gate electrode. Note that although the gate electrodes 313 and 314 appear to be two in the cross section, they are actually electrically connected.
[0113]
Next, as shown in FIG. 5A, an n-type impurity element (phosphorus in this embodiment) is added in a self-aligning manner using the gate electrodes 311 to 315 as a mask. The impurity regions 316 to 323 thus formed are adjusted so that phosphorus is added at a concentration of 1/2 to 1/10 (typically 1/3 to 1/4) of the n-type impurity region 305. Specifically, 1 × 10 ¹⁶ ~ 5x10 ¹⁸ atoms / cm ^Three (Typically 3x10 ¹⁷ ~ 3x10 ¹⁸ atoms / cm ^Three ) Is preferred.
[0114]
Next, as shown in FIG. 5B, resist masks 324a to 324d are formed so as to cover the gate electrodes and the like, and an n-type impurity element (phosphorus in this embodiment) is added to contain phosphorus at a high concentration. Impurity regions 325 to 329 are formed. Again, phosphine (PH _Three The concentration of phosphorus in this region is 1 × 10 ²⁰ ~ 1x10 ^{twenty one} atoms / cm ^Three (Typically 2 × 10 ²⁰ ~ 5x10 ^{twenty one} atoms / cm ^Three ).
[0115]
In this step, the source region or drain region of the n-channel TFT is formed. However, in the switching TFT, a part of the n-type impurity regions 319 to 321 formed in the step of FIG. This remaining region corresponds to the LDD regions 15a to 15d of the switching TFT 201 in FIG.
[0116]
Next, as shown in FIG. 5C, the resist masks 324a to 324d are removed, and a new resist mask 332 is formed. Then, a p-type impurity element (boron in this embodiment) is added to form impurity regions 333 to 336 containing boron at a high concentration. Here, diborane (B ₂ H ₆ 3 × 10 by ion doping method using ²⁰ ~ 3x10 ^{twenty one} atoms / cm ^Three (Typically 5 × 10 ²⁰ ~ 1x10 ^{twenty one} atoms / cm ^Three B) Add boron to achieve a concentration.
[0117]
The impurity regions 333 to 336 are already 1 × 10 ²⁰ ~ 1x10 ^{twenty one} atoms / cm ^Three However, the boron added here is added at a concentration at least three times that of phosphorus. Therefore, the n-type impurity region formed in advance is completely inverted to the p-type and functions as a p-type impurity region.
[0118]
Next, after removing the resist mask 332, the n-type or p-type impurity element added at each concentration is activated. As the activation means, furnace annealing, laser annealing, or lamp annealing can be used. In this embodiment, heat treatment is performed in an electric furnace in a nitrogen atmosphere at 550 ° C. for 4 hours.
[0119]
At this time, it is important to eliminate oxygen in the atmosphere as much as possible. This is because the presence of even a small amount of oxygen oxidizes the exposed surface of the gate electrode, which increases resistance and makes it difficult to make ohmic contact later. Therefore, the oxygen concentration in the treatment atmosphere in the activation step is 1 ppm or less, preferably 0.1 ppm or less.
[0120]
Next, when the activation process is completed, a gate wiring 337 having a thickness of 300 nm is formed as shown in FIG. As a material for the gate wiring 337, a metal containing aluminum (Al) or copper (Cu) as a main component (occupying 50 to 100% as a composition) may be used. As shown in FIG. 3, the gate wiring 211 and the switching TFT gate electrodes 19a and 19b (313 and 314 in FIG. 4E) are electrically connected as shown in FIG.
[0121]
With such a structure, the wiring resistance of the gate wiring can be extremely reduced, so that an image display region (pixel portion) having a large area can be formed. That is, the pixel structure of this embodiment is extremely effective in realizing an EL display device having a screen size of 10 inches or more (or 30 inches or more) diagonally.
[0122]
Next, as shown in FIG. 6A, a first interlayer insulating film 338 is formed. As the first interlayer insulating film 338, an insulating film containing silicon may be used as a single layer, or a stacked film in which two or more kinds of insulating films containing silicon are combined may be used. The film thickness may be 400 nm to 1.5 μm. In this embodiment, a structure is formed in which a silicon oxide film having a thickness of 800 nm is stacked on a silicon nitride oxide film having a thickness of 200 nm.
[0123]
Further, a hydrogenation treatment is performed by performing a heat treatment at 300 to 450 ° C. for 1 to 12 hours in an atmosphere containing 3 to 100% hydrogen. This step is a step in which the dangling bonds of the semiconductor film are terminated with hydrogen by thermally excited hydrogen. As another means for hydrogenation, plasma hydrogenation (using hydrogen generated by plasmatization) may be performed.
[0124]
Note that the hydrogenation treatment may be performed while the first interlayer insulating film 338 is formed. That is, a hydrogenation treatment may be performed as described above after a 200 nm thick silicon nitride oxide film is formed, and then the remaining 800 nm thick silicon oxide film may be formed.
[0125]
Next, contact holes are formed in the first interlayer insulating film 338 and the gate insulating film 310, and source wirings 339 to 342 and drain wirings 343 to 345 are formed. In this embodiment, this electrode is a laminated film having a three-layer structure in which a Ti film is 100 nm, an aluminum film containing Ti is 300 nm, and a Ti film 150 nm is continuously formed by sputtering. Of course, other conductive films may be used.
[0126]
Next, a first passivation film 346 is formed with a thickness of 50 to 500 nm (typically 200 to 300 nm). In this embodiment, a silicon nitride oxide film having a thickness of 300 nm is used as the first passivation film 346. This may be replaced by a silicon nitride film.
[0127]
Prior to the formation of the silicon nitride oxide film, H ₂ , NH _Three It is effective to perform plasma treatment using a gas containing isohydrogen. Hydrogen excited by this pretreatment is supplied to the first interlayer insulating film 338 and heat treatment is performed, whereby the film quality of the first passivation film 346 is improved. At the same time, hydrogen added to the first interlayer insulating film 338 diffuses to the lower layer side, so that the active layer can be effectively hydrogenated.
[0128]
Next, as shown in FIG. 6B, a second interlayer insulating film 347 made of an organic resin is formed. As the organic resin, polyimide, polyamide, acrylic resin, BCB (benzocyclobutene), or the like can be used. In particular, since the second interlayer insulating film 347 has a strong meaning of flattening, an acrylic resin excellent in flatness is preferable. In this embodiment, the acrylic resin film is formed with a film thickness that can sufficiently flatten the step formed by the TFT. The thickness is preferably 1 to 5 μm (more preferably 2 to 4 μm).
[0129]
Next, contact holes are formed in the second interlayer insulating film 347 and the first passivation film 346, and a pixel electrode 348 that is electrically connected to the drain wiring 345 is formed. In this embodiment, an indium tin oxide (ITO) film having a thickness of 110 nm is formed and patterned to form a pixel electrode. Alternatively, a compound in which 2 to 20% zinc oxide (ZnO) is mixed with indium oxide, or a compound made of zinc oxide and gallium oxide may be used as the transparent electrode. This pixel electrode becomes the anode of the EL element.
[0130]
Next, as shown in FIG. 6C, a bank a (349a) and a bank b (349b) made of a resin material are formed. The bank a (349a) and the bank b (349b) may be formed by laminating films such as an acrylic resin film or a polyimide film having a total thickness of 1 to 2 μm and then patterning them. Note that it is necessary to select a material having a higher etching rate for the same etching material as the film for forming the bank a (349a) than the film for forming the bank b (349b). The bank a (349a) and the bank b (349b) are formed in a stripe shape between pixels as shown in FIG. In this embodiment, it is formed along the source wiring 341, but it may be formed along the gate wiring 337.
[0131]
Next, the EL layer 350 is formed by the thin film formation method described in FIG. Although only one pixel is shown here, EL layers corresponding to each color of R (red), G (green), and B (blue) are formed as described in FIG.
[0132]
First, the EL material provided in the sample boat evaporates by resistance heating from the electrodes, and becomes an EL material in a vapor state. The vaporized EL material is intentionally charged and then released. The emitted EL material in the vapor state passes through a mask to which voltage is applied, and is then deposited on the pixel portion on the substrate 110. Note that the traveling direction of the vaporized EL material is controlled by an electric field in the vicinity of the mask when passing through the mask.
[0133]
In this embodiment, first, a red EL material is discharged from a sample boat as an EL material in a vapor state to form a pixel row that emits red light on the pixel. Next, after the mask is moved in the horizontal direction, a green EL material is vapor-deposited from the sample boat to form a pixel row that should emit green light. Further, the mask is moved in the horizontal direction to deposit blue EL material from the sample boat, thereby forming a pixel row to emit blue light.
[0134]
As described above, the pixel array that emits red, green, and blue light is vapor-deposited three times for each color while the mask is moved to form a three-color stripe-shaped EL layer.
[0135]
Although only one pixel is illustrated in this embodiment, the EL layers that emit light of the same color are formed at the same time.
[0136]
In this example, as the EL material, a red EL layer doped with red fluorescent dye DCM using Alq as a host material was used. Further, Alq which is an 8-hydroxyquinoline complex of aluminum is used for an EL layer emitting green light, and a zinc benzoxazole complex (Zn (oxz)) is used for an EL layer emitting blue light. ₂ ) And each having a thickness of 50 nm.
[0137]
A known material can be used for the EL layer 350. As the known material, it is preferable to use an organic material in consideration of the driving voltage. In this embodiment, the EL layer 350 has a single-layer structure composed of only the EL layer, but an electron injection layer, an electron transport layer, a hole transport layer, a hole injection layer, an electron blocking layer, or a hole is formed as necessary. An element layer may be provided. In this embodiment, an example in which an MgAg electrode is used as the cathode 351 of the EL element is shown, but other known materials may be used.
[0138]
The EL layer is vapor-deposited for each color EL layer, but these electron injection layer, electron transport layer, hole transport layer, hole injection layer, electron blocking layer or hole element layer are the colors of the EL layer. Regardless of the method, the same material may be formed at a time using a method such as spin coating or vapor deposition.
[0139]
After the EL layer 350 is formed, a cathode (MgAg electrode) 351 is formed using a vacuum evaporation method. Note that the EL layer 350 may have a thickness of 80 to 200 nm (typically 100 to 120 nm), and the cathode 351 may have a thickness of 180 to 300 nm (typically 200 to 250 nm).
[0140]
Further, a protective electrode 352 is provided on the cathode 351. As the protective electrode 352, a conductive film containing aluminum as its main component may be used. The protective electrode 352 may be formed by a vacuum evaporation method using a mask.
[0141]
Finally, a second passivation film 353 made of a silicon nitride film is formed to a thickness of 300 nm. Actually, the protective electrode 352 plays a role of protecting the EL layer from moisture and the like, but the reliability of the EL element can be further improved by forming the second passivation film 353.
[0142]
FIG. 7 shows a cross-sectional structure of an n-channel type switching TFT as the TFT in the pixel portion.
[0143]
First, the switching TFT shown in FIG. 7 is provided in FIG. 7A so that the LDD regions 15a to 15d do not overlap the gate electrodes 19a and 19b with the gate insulating film 18 interposed therebetween. Such a structure is very effective in reducing the off-current value.
[0144]
On the other hand, these LDD regions 15a to 15d are not provided in FIG. In the case of the structure shown in FIG. 7B, the number of steps can be reduced compared with the case where the structure shown in FIG. 7A is formed, so that the production efficiency can be improved.
[0145]
In this embodiment, either of the structures shown in FIGS. 7A and 7B may be used as the switching TFT.
[0146]
Next, as a TFT in the pixel portion, FIG. 8 shows a cross-sectional structure diagram of an n-channel type current control TFT.
[0147]
In the current control TFT shown in FIG. 8A, an LDD region 33 is provided between the drain region 32 and the channel formation region 34. Here, a structure in which the LDD region 33 has a region that overlaps the gate electrode 35 and a region that does not overlap with the gate insulating film 18 interposed therebetween is shown, but the LDD region 33 is provided as shown in FIG. It is good also as a structure without.
[0148]
The current control TFT supplies a current for causing the EL element to emit light, and at the same time controls the supply amount to enable gradation display. Therefore, it is necessary to take measures against deterioration by hot carrier injection so that it does not deteriorate even when current is passed.
[0149]
Regarding deterioration due to hot carrier injection, it is known that a structure in which an LDD region overlaps a gate electrode is very effective. Therefore, as shown in FIG. 8A, a structure in which an LDD region is provided in a region overlapping with the gate electrode 35 with the gate insulating film 18 interposed therebetween is suitable. A structure in which an LDD region that does not become necessary is also provided is shown. However, the LDD region that does not overlap with the gate electrode is not necessarily provided. In some cases, these LDD regions may not be provided as shown in FIG.
[0150]
In this embodiment, as shown in FIG. 6C, the active layer of the n-channel type 205 includes a source region 355, a drain region 356, an LDD region 357, and a channel formation region 358, and the LDD region 357 has gate insulation. The gate electrode 312 overlaps with the film 310 interposed therebetween.
[0151]
The reason why the LDD region is formed only on the drain region side is to prevent the operation speed from being lowered. In addition, the n-channel TFT 205 does not need to care about the off-current value, and it is better to focus on the operation speed than that. Therefore, it is desirable that the LDD region 357 is completely overlapped with the gate electrode and the resistance component is reduced as much as possible. That is, it is better to eliminate the so-called offset.
[0152]
Thus, an active matrix substrate having a structure as shown in FIG. 6C is completed. Note that it is effective to continuously process the steps from the formation of the bank 349 to the formation of the passivation film 353 using a multi-chamber type (or in-line type) thin film forming apparatus without releasing to the atmosphere. .
[0153]
By the way, the active matrix substrate of this embodiment can provide extremely high reliability and improve the operating characteristics by arranging TFTs having an optimal structure not only in the pixel portion but also in the drive circuit portion.
[0154]
First, a TFT having a structure that reduces hot carrier injection so as not to decrease the operating speed as much as possible is used as an n-channel TFT 205 of a CMOS circuit that forms a drive circuit portion. Note that the drive circuit here includes a shift register, a buffer, a level shifter, a sampling circuit (sample and hold circuit), and the like. In the case of performing digital driving, a signal conversion circuit such as a D / A converter may be included.
[0155]
Actually, after completion of FIG. 6C, it is preferable to package (enclose) with a cover material such as highly airtight glass, quartz, or plastic so as not to be exposed to the outside air. At that time, a hygroscopic agent such as barium oxide or an antioxidant may be disposed inside the cover material.
[0156]
In addition, if the airtightness is improved by processing such as packaging, a connector (flexible printed circuit: FPC) for connecting the terminal drawn from the element or circuit formed on the insulator and the external signal terminal is attached. Completed as a product. In this specification, such a state that can be shipped is referred to as an EL display device (or EL module).
[0157]
Here, the configuration of the active matrix EL display device of this embodiment will be described with reference to the perspective view of FIG. The active matrix EL display device of this embodiment includes a pixel portion 602, a gate side driver circuit 603, and a source side driver circuit 604 formed on a glass substrate 601. The switching TFT 605 in the pixel portion is an n-channel TFT, and is arranged at the intersection of the gate wiring 606 connected to the gate side driving circuit 603 and the source wiring 607 connected to the source side driving circuit 604. The drain of the switching TFT 605 is connected to the gate of the current control TFT 608.
[0158]
Further, the source side of the current control TFT 608 is connected to the power supply line 609. In the structure as in this embodiment, a ground potential (ground potential) is applied to the power supply line 609. An EL element 610 is connected to the drain of the current control TFT 608. A predetermined voltage (3 to 12 V, preferably 3 to 5 V) is applied to the anode of the EL element 610.
[0159]
The FPC 611 serving as an external input / output terminal is provided with connection wirings 612 and 613 for transmitting signals to the drive circuit portion, and connection wiring 614 connected to the power supply line 609.
[0160]
FIG. 10 shows an example of a circuit configuration of the EL display device shown in FIG. The EL display device of this embodiment includes a source side driver circuit 801, a gate side driver circuit (A) 807, a gate side driver circuit (B) 811, and a pixel portion 806. Note that in this specification, the drive circuit portion is a generic term including a source side processing circuit and a gate side drive circuit.
[0161]
The source side driver circuit 801 includes a shift register 802, a level shifter 803, a buffer 804, and a sampling circuit (sample and hold circuit) 805. The gate side driver circuit (A) 807 includes a shift register 808, a level shifter 809, and a buffer 810. The gate side driver circuit (B) 811 has a similar structure.
[0162]
Here, the driving voltages of the shift registers 802 and 808 are 5 to 16 V (typically 10 V), and an n-channel TFT used in a CMOS circuit forming the circuit has a structure indicated by 205 in FIG. Is suitable.
[0163]
As the level shifters 803 and 809 and the buffers 804 and 810, a CMOS circuit including the n-channel TFT 205 in FIG. In addition, it is effective in improving the reliability of each circuit that the gate wiring has a multi-gate structure such as a double gate structure or a triple gate structure.
[0164]
The pixel portion 806 is provided with pixels having the structure shown in FIG.
[0165]
In addition, the said structure can be easily implement | achieved by manufacturing TFT according to the manufacturing process shown to FIGS. Further, in this embodiment, only the configuration of the pixel portion and the drive circuit portion is shown. However, according to the manufacturing process of this embodiment, a signal dividing circuit, a D / A converter circuit, an operational amplifier circuit, a γ correction circuit, etc. It is considered that logic circuits other than the drive circuit can be formed on the same insulator, and further, a memory portion, a microprocessor, and the like can be formed.
[0166]
Further, the EL module of this embodiment including the cover material will be described with reference to FIGS. Note that the reference numerals used in FIGS. 9 and 10 are cited as necessary.
[0167]
FIG. 11A is a top view showing a state in which a sealing structure is provided in the state shown in FIG. Reference numeral 602 indicated by a dotted line denotes a pixel portion, 603 denotes a gate side driver circuit, and 604 denotes a source side driver circuit. The sealing structure of the present embodiment is a structure in which a cover material 1101 and a seal material (not shown) are provided in the state of FIG.
[0168]
Here, FIG. 11B is a cross-sectional view taken along line AA ′ of FIG. In FIGS. 11A and 11B, the same reference numerals are used for the same parts.
[0169]
As shown in FIG. 11B, a pixel portion 602 and a gate side driver circuit 603 are formed over a substrate 601, and the pixel portion 602 includes a current control TFT 202 and a pixel electrode 346 electrically connected thereto. A plurality of pixels are included. The gate driver circuit 603 is formed using a CMOS circuit in which an n-channel TFT 205 and a p-channel TFT 206 are complementarily combined.
[0170]
The pixel electrode 348 functions as an anode of the EL element. A bank a (349a) and a bank b (349b) are formed in the gap between the pixel electrodes 348, and an EL layer 350 and a cathode 351 are formed inside the bank a (349a) and the bank b (349b). A protective electrode 352 and a second passivation film 353 are formed thereon. Of course, as described in the embodiment of the invention, the structure of the EL element may be reversed and the pixel electrode may be a cathode.
[0171]
In this embodiment, the protective electrode 352 also functions as a common wiring for each pixel column, and is electrically connected to the FPC 611 via the connection wiring 612. Further, all elements included in the pixel portion 602 and the gate side driving circuit 603 are covered with the second passivation film 353. Although the second passivation film 353 can be omitted, it is preferable to provide the second passivation film 353 to shield each element from the outside.
[0172]
Further, a cover material 1001 is bonded by a seal material 1004. Note that a spacer made of a resin film may be provided in order to ensure a gap between the cover material 1001 and the light emitting element. Note that the inner side 1103 of the sealant 1004 is a sealed space and is filled with an inert gas such as nitrogen or argon. It is also effective to provide a hygroscopic material typified by barium oxide in the sealed space 1103.
[0173]
Further, a filler can be provided in the space 1103. As the filler, PVC (polyvinyl chloride), epoxy resin, silicone resin, PVB (polyvinyl butyral) or EVA (ethylene vinyl acetate) can be used.
[0174]
In this embodiment, as the cover material 1101, a material made of glass, plastic, and ceramics can be used.
[0175]
As the sealant 1104, a photocurable resin is preferably used, but a thermosetting resin may be used if the heat resistance of the EL layer permits. Note that the sealing material 1104 is preferably a material that does not transmit moisture and oxygen as much as possible. Further, a desiccant may be added inside the sealing material 1104.
[0176]
By sealing the EL element using the above-described method, the EL element can be completely shut off from the outside, and substances that promote deterioration due to oxidation of the EL layer, such as moisture and oxygen, enter from the outside. Can be prevented. Accordingly, a highly reliable EL display device can be manufactured. In this embodiment, an example in which three types of stripe-shaped EL layers emitting red, green, and blue light are respectively formed in the vertical direction is shown, but they may be formed in the horizontal direction.
[0177]
Moreover, the structure of a present Example can be freely combined with the structure of Example 1- Example 3. FIG.
[0178]
Example 5
When the active matrix EL display device of the present invention is viewed in the direction of FIG. 11A, the pixel columns may be formed in a stripe shape in the vertical direction or in a delta arrangement.
[0179]
Here, how the pixels of three colors of red, green, and blue are formed in a stripe shape on the substrate will be described. Note that the colors of the pixels are not necessarily three colors, and may be one color or two colors. Further, the color is not limited to red, green, and blue, and other colors such as yellow, orange, and gray may be used.
[0180]
Note that the positional relationship between the substrate, the sample boat provided with the EL material, and the mask for controlling the EL material in the vapor state is as shown in FIG.
[0181]
First, the EL material for the red EL layer is provided in the sample boat, and when vaporized by the sample boat, the vaporized EL material is released from the sample boat. At this time, since a predetermined voltage is applied to the mask, the emitted EL material in the vapor state is controlled by the electric field when it reaches the mask and passes through the mask to reach a desired pixel portion. Thereby, vapor deposition control to the desired position of a pixel part is attained. It is sufficient that a voltage of several tens of volts to 10 kV is applied to the mask.
[0182]
First, a red EL material is deposited. Since a voltage is applied to the mask, the EL material can be selectively deposited at a desired position in the pixel portion.
[0183]
As a mask for forming the stripe EL layer in the pixel portion 704, a stripe mask 500 illustrated in FIG. 12A is preferably used. Note that a mask capable of forming pixels in a delta arrangement may be used as the mask.
[0184]
In this embodiment, first, a red EL material is vapor-deposited using the stripe-shaped mask 500 shown in FIG. 12A, and then the stripe-shaped mask 500 is arranged for one pixel column in the horizontal direction indicated by the arrow i. After the movement, a green EL material is deposited. After that, the mask 500 is further moved by one pixel column in the horizontal direction indicated by the arrow i, and then a blue EL material is vapor-deposited to form a stripe-shaped EL layer made of red, green, and blue on the pixel portion. Let it form.
[0185]
Note that by using these masks to form red EL material, green EL material, and blue EL material in the pixel portion, stripe pixels can be formed in the pixel portion as shown in FIG. .
[0186]
A stripe mask 500 shown in FIG. 12A is used as a mask for forming the stripe-shaped EL layer in the pixel portion 704, and a mask for forming pixels in the delta arrangement is shown in FIG. 12B. A delta arrangement mask 501 shown may be used.
[0187]
In FIG. 13A, reference numeral 704a denotes an EL layer emitting red light, 704b denotes an EL layer emitting green light, and an EL layer 704c emitting blue light is formed. Banks (not shown) are formed in stripes in the vertical direction along the source wiring above the source wiring via the insulating film.
[0188]
Here, the EL layer refers to a layer made of an organic EL material that contributes to light emission, such as an EL layer, a charge injection layer, and a charge transport layer. In some cases, the EL layer may be a single layer. For example, when a hole injection layer and an EL layer are stacked, the stacked film is referred to as an EL layer.
[0189]
At this time, the distance (D) between pixels adjacent to each other in the same color line is desirably 5 times or more (preferably 10 times) or more of the film thickness (t) of the EL layer. This is because a problem of crosstalk may occur between pixels when D <5t. In addition, since a high-definition image cannot be obtained even if the distance (D) is too far, it is preferable that 5t <D <50t (preferably 10t <D <35t).
[0190]
Alternatively, the banks may be formed in stripes in the horizontal direction, and an EL layer that emits red light, an EL layer that emits green light, and an EL layer that emits blue light may be formed horizontally.
At this time, the bank (not shown) is formed along the gate wiring above the gate wiring through the insulating film.
[0191]
Also in this case, the distance (D) between pixels adjacent to each other in the same color line is 5 times or more (preferably 10 times or more) of the film thickness (t) of the EL layer, more preferably 5t <D <50t ( Preferably, 10t <D <35t).
[0192]
The vapor deposition position can be controlled by electrically controlling the EL material in the vapor state when the EL layer is formed by vapor deposition as in this embodiment.
[0193]
In addition, the structure of a present Example can be implemented in combination with any structure of Example 1- Example 4 freely.
[0194]
Example 6
In this embodiment, the case where the present invention is used in a passive type (simple matrix type) EL display device will be described. FIG. 14 is used for the description. In FIG. 14, 1301 is a substrate made of plastic, and 1302 is an anode made of a transparent conductive film. In this embodiment, a compound of indium oxide and zinc oxide is formed as a transparent conductive film by a vapor deposition method. Although not shown in FIG. 14, a plurality of anodes are arranged in stripes in a direction parallel to the paper surface.
[0195]
Further, a bank composed of a bank a (1303a) and a bank b (1303b) is formed in a direction perpendicular to the paper surface so as to fill in the space between the cathodes 1305 arranged in a stripe shape.
[0196]
Next, EL layers 1304a to 1304c made of an EL material are formed by vapor deposition as shown in FIG. Note that 1304a is an EL layer emitting red light, 1304b is an EL layer emitting green light, and 1304c is an EL layer emitting blue light. The same organic EL material as that used in Example 1 may be used. Since these EL layers are formed along the grooves formed by the bank a (1303a) and the bank b (1303b), they are arranged in stripes in a direction perpendicular to the paper surface.
[0197]
In this embodiment, the position where the EL material is deposited on the anode is controlled not only by a mask but also by applying a voltage on the anode.
[0198]
Thereafter, although not shown in FIG. 14, a plurality of cathodes and protective electrodes are arranged in stripes so that the direction perpendicular to the paper surface is the longitudinal direction and perpendicular to the anode 1302. In this embodiment, the cathode 1305 is made of MgAg, and the protective electrode 1306 is made of an aluminum alloy film, which are formed by vapor deposition. Further, although not shown, the protective electrode 1306 is extended to a portion where an FPC is attached later so that a predetermined voltage is applied.
[0199]
Although not shown here, when the protective electrode 1306 is formed, a silicon nitride film may be provided as a passivation film.
[0200]
As described above, an EL element is formed over the substrate 1301. In this embodiment, since the lower electrode is a light-transmitting anode, light generated in the EL layers 1304a to 1304c is emitted to the lower surface (substrate 1301). However, the structure of the EL element can be reversed, and the lower electrode can be a light-shielding cathode. In that case, light generated in the EL layers 1304a to 1304c is emitted to the upper surface (the side opposite to the substrate 1301).
[0201]
Next, a ceramic substrate is prepared as the cover material 1307. In the structure of the present embodiment, a ceramic substrate is used because the light shielding property is sufficient. Of course, when the structure of the EL element is reversed as described above, the cover material is better translucent, and thus is made of plastic or glass. A substrate may be used.
[0202]
The cover material 1307 thus prepared is bonded with a sealant 1309 made of an ultraviolet curable resin. Note that an inner side 1308 of the sealant 1309 is a sealed space and is filled with an inert gas such as nitrogen or argon. It is also effective to provide a moisture absorbing material typified by barium oxide in the sealed space 1308. Finally, an anisotropic conductive film (FPC) 1311 is attached to complete a passive EL display device.
[0203]
In addition, the structure of a present Example can be implemented in combination with any structure of Example 1- Example 5 freely.
[0204]
Example 7
When an active matrix EL display device is manufactured by implementing the present invention, it is effective to use a silicon substrate (silicon wafer) as a substrate. When a silicon substrate is used as a substrate, a switching element formed in the pixel portion, a current control element, or a drive element formed in the drive circuit portion is manufactured using a MOSFET manufacturing technique used in conventional ICs or LSIs. Can be used.
[0205]
A MOSFET can form a circuit with very little variation, as proven in ICs and LSIs, and is particularly effective for an analog-driven active matrix EL display device that expresses gradation with current values.
[0206]
Note that since the silicon substrate is light-shielding, it is necessary to have a structure in which light from the EL layer is emitted to the side opposite to the substrate. The EL display device of this embodiment is structurally similar to that shown in FIG. 14, but differs in that MOSFETs are used instead of TFTs forming the pixel portion 602 and the drive circuit portion 603.
[0207]
In addition, the structure of a present Example can be implemented in combination freely with any structure of Example 1- Example 6. FIG.
[0208]
Example 8
Since the EL display device formed by implementing each of the above embodiments is a self-luminous type, it has excellent visibility in a bright place and a wide viewing angle as compared with a liquid crystal display device. Therefore, it can be used as a display portion of various electronic devices. For example, in order to view TV broadcasts on a large screen, the EL of the present invention can be used as a display unit of an EL display (a display in which an EL display device is incorporated in a housing) having a diagonal size of 30 inches or more (typically 40 inches or more). A display device may be used.
[0209]
The EL display includes all information display displays such as a personal computer display, a TV broadcast receiving display, and an advertisement display. In addition, the EL display device of the present invention can be used as a display portion of various electronic devices.
[0210]
Such an electronic device of the present invention includes a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, a sound reproduction device (car audio, audio component, etc.), a notebook type personal computer, a game machine, a mobile phone. Information terminal (mobile computer, mobile phone, portable game machine, electronic book, etc.), image playback device equipped with a recording medium (specifically, playback of a recording medium such as a digital video disc (DVD), and display the image) And a device equipped with a display that can be used. In particular, since a portable information terminal that is often viewed from an oblique direction emphasizes the wide viewing angle, it is desirable to use an EL display device. Specific examples of these electronic devices are shown in FIGS.
[0211]
FIG. 15A illustrates an EL display which includes a housing 2001, a support base 2002, a display portion 2003, and the like. The present invention can be used for the display portion 2003. Since the EL display is a self-luminous type, a backlight is not necessary, and a display portion thinner than a liquid crystal display can be obtained.
[0212]
FIG. 15B shows a video camera, which includes a main body 2101, a display portion 2102, an audio input portion 2103, operation switches 2104, a battery 2105, an image receiving portion 2106, and the like. The EL display device of the present invention can be used for the display portion 2102.
[0213]
FIG. 15C shows a part (right side) of a head-mounted EL display, which includes a main body 2201, a signal cable 2202, a head fixing band 2203, a display portion 2204, an optical system 2205, an EL display device 2206, and the like. Including. The present invention can be used for the EL display device 2206.
[0214]
FIG. 15D shows an image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, which includes a main body 2301, a recording medium (DVD or the like) 2302, an operation switch 2303, a display portion (a) 2304, a display portion. (B) 2305 and the like are included. The display unit (a) mainly displays image information, and the display unit (b) mainly displays character information. The EL display device of the present invention can be used for these display units (a) and (b). Note that an image reproducing device provided with a recording medium includes a home game machine and the like.
[0215]
FIG. 15E illustrates a portable (mobile) computer, which includes a main body 2401, a camera portion 2402, an image receiving portion 2403, operation switches 2404, a display portion 2405, and the like. The EL display device of the present invention can be used for the display portion 2405.
[0216]
FIG. 15F illustrates a personal computer, which includes a main body 2501, a housing 2502, a display portion 2503, a keyboard 2504, and the like. The EL display device of the present invention can be used for the display portion 2503.
[0217]
If the emission luminance of the organic EL material is increased in the future, the light including the output image information can be enlarged and projected by a lens or the like and used for a front type or rear type projector.
[0218]
In addition, the electric appliances often display information distributed through electronic communication lines such as the Internet or CATV (cable television), and in particular, opportunities to display moving image information are increasing. Since the response speed of the organic EL material is very high, the EL display device is preferable for moving image display. However, if the contour between pixels is blurred, the entire moving image is blurred. Therefore, it is extremely effective to use the EL display device of the present invention for clarifying the contour between pixels as a display unit of an electric appliance.
[0219]
In addition, since the EL display device consumes power in the light emitting portion, it is desirable to display information so that the light emitting portion is minimized. Accordingly, when an EL display device is used for a display unit mainly including character information such as a portable information terminal, particularly a mobile phone or a sound reproduction device, the character information is formed by the light emitting portion with the non-light emitting portion as the background. It is desirable to drive.
[0220]
Here, FIG. 16A shows a mobile phone, which includes a main body 2601, an audio output portion 2602, an audio input portion 2603, a display portion 2604, operation switches 2605, and an antenna 2606. The EL display device of the present invention can be used for the display portion 2604. Note that the display portion 2604 can suppress power consumption of the mobile phone by displaying white characters on a black background.
[0221]
FIG. 16B shows a sound reproducing device, specifically a car audio, which includes a main body 2701, a display portion 2702, and operation switches 2703 and 2704. The EL display device of the present invention can be used for the display portion 2702. Moreover, although the vehicle-mounted audio is shown in the present embodiment, it may be used for a portable or household sound reproducing device. Note that the display portion 2704 can suppress power consumption by displaying white characters on a black background. This is particularly effective in a portable sound reproducing apparatus.
[0222]
As described above, the application range of the present invention is extremely wide and can be used for electric appliances in various fields. Moreover, you may use the EL display apparatus of any structure shown in Examples 1-7 for the electric appliance of a present Example.
[0223]
Example 9
In this embodiment, a description will be given of a method of forming an EL material vaporized in a sample boat (hereinafter referred to as an EL material in a vapor state) on a substrate by controlling with an electric field using a plurality of masks. Note that FIG. 17 is used as a vapor deposition method in this embodiment.
[0224]
In FIG. 17, 1010 is a substrate and 1011 is a sample boat. Note that the sample boat 1011 is provided with an EL material.
[0225]
Further, the sample boat 1011, the first mask, and the second mask described here may be provided separately, but may be integrally formed as an apparatus.
[0226]
When the red EL layer is formed, the sample boat 1011 has an EL material that emits red light (hereinafter referred to as a red EL material). When the green EL layer is formed, the sample boat 1011 has an EL material that emits green light ( Hereinafter, when forming a blue EL layer, the sample boat 1011 is provided with an EL material that emits blue light (hereinafter referred to as a blue EL material).
[0227]
In this example, as the EL material, a red EL layer doped with red fluorescent dye DCM using Alq as a host material was used. Further, Alq which is an 8-hydroxyquinoline complex of aluminum is used for an EL layer emitting green light, and a zinc benzoxazole complex (Zn (oxz)) is used for an EL layer emitting blue light. ₂ ) Is used.
[0228]
Note that the above-described EL material is one of the examples, and other known EL materials may be used. Further, although the EL materials are selected with the emission colors of red, green, and blue, the present invention is not limited to this, and colors such as yellow, orange, and gray may be used.
[0229]
In this embodiment, a sample boat is first provided with a red EL material, a red EL layer is formed on the substrate, and then a green EL layer is formed on the substrate using the sample boat provided with the green EL material. . Finally, a blue EL layer is formed on the substrate using a sample boat provided with a blue EL material.
[0230]
As described above, the EL layer can be formed by evaporating the red, green, and blue EL materials in three portions.
[0231]
First, the EL material provided in the sample boat 1011 is vaporized (evaporated) by resistance heating with the electrode 1012. At the moment when the vaporized EL material jumps out of the sample boat 1011, the vaporized EL material is charged by the influence of the electric field by the electrode 1020 attached to the opening of the sample boat 1011 and becomes charged particles. The traveling direction of the charged particles is controlled by an electric field in the vicinity of the mask generated by applying a voltage to the first blocking unit 1018 and the second blocking unit 1019b when passing through the mask 1013.
[0232]
Note that an electric field may be generated by providing an electrode between the sample boat and the mask, and the electric charge of the vaporized EL material discharged from the sample boat may be controlled.
[0233]
As a result, the gas EL material is deposited on the surface to be formed on the substrate through the gaps between the first blocking portions and the second blocking portions.
[0234]
The first mask 1013 includes a plurality of conductive lines made of a conductive material such as copper, iron, aluminum, tantalum, titanium, and tungsten in a portion of the first blocking portion 1018 (stripe shape). ), Or a mesh-like structure (mesh shape) or a plate-like structure. The second mask 1019a includes a second blocking portion 1019b in which a plurality of conductive lines made of a conductive material such as copper, iron, aluminum, tantalum, titanium, and tungsten are arranged in parallel to each other (stripe shape). ), Or a net-like structure (mesh shape) or a plate-like structure. Since the EL material in the vapor state repels the electric field generated by the negative voltage applied to the first blocking unit 1018, it passes through the gap between the first blocking units 1018 and further applies the negative voltage applied to the second blocking unit 1019b. In order to repel the electric field generated by the above, it is deposited on the substrate through the gap between the second blocking portions 1019b.
[0235]
In addition, although an example in which the cross-sectional shape is circular is shown in FIG. 17, it is not particularly limited, and may be rectangular, elliptical, or polygonal.
[0236]
Note that a voltage is applied to the first blocking unit 1018 of the first mask 1013 so that the EL material in a vapor state repels the first blocking unit 1018 of the first mask 1013. Thereby, the EL material can pass through the gap between the first blocking portions 1018 in the first mask 1013. Note that here, the EL material in a vapor state is charged by an electric field generated by the electrode 1012 to which a negative voltage is applied, and an electric field is generated by applying a negative voltage to the first blocking portion of the first mask by the electrode 1015a.
Also, a negative voltage is applied to the second blocking part of the second mask by the electrode 1015b to generate an electric field. As a result, the charged particles of the EL material in the vapor state are electrically repelled from the first blocking unit and the second blocking unit, and pass through the gaps between the first blocking unit and the second blocking unit.
[0237]
The structure shown in FIG. 1A is used, and a negative first voltage applied to the first blocking unit 1018 and a negative second voltage applied to the second blocking unit 1019b are appropriately set within a range of several tens of volts to 10 kV. By adjusting, the deposition position can be controlled with high accuracy.
[0238]
The practitioner determines the distance between the first mask 1013 and the second mask 1019a, the distance between the second mask 1019a and the substrate, the distance between each first blocking part 1018, the distance between each second blocking part 1019b, etc. You only have to set it. For example, the distance between the first blocking portions 1018 and the distance between the second blocking portions 1019b may be set to the pixel pitch of the pixel electrodes formed on the substrate.
[0239]
Moreover, the opening part of a mask has pointed out the clearance gap between each 1st interruption | blocking part, or the clearance gap between each 2nd interruption | blocking part.
[0240]
Further, in the present specification, the surface to be formed is a part of the surface of the pixel electrode or the organic film and means a surface on which a thin film is to be formed.
[0241]
Further, the EL material in a vapor state that is negatively charged by applying a negative voltage to the inner side surface of the vapor deposition chamber 1021 provided with the sample boat 1011, the first mask, the second mask, and the substrate 1010 with an electrode 1014. Since the inner side surface of the vapor deposition chamber can be repelled, the vaporized EL material can be deposited on the surface to be formed without adhering to the inner side of the vapor deposition chamber.
[0242]
Further, when the red EL material of the sample boat 1011 is deposited, a striped red EL layer is formed on the pixel. Here, the mask is moved by one pixel in the direction of the arrow k, and the green EL material is similarly deposited from the sample boat 1011. Thereby, a green EL layer is formed beside the red EL layer. Further, the blue EL material is deposited from the sample boat 1011 while moving the mask by one row of pixels in the direction of the arrow k. Thereby, a blue EL layer is formed beside the green EL layer. That is, by moving the pixel row emitting red, green, and blue in three times for each color while evaporating the mask as described above, a three-color striped EL layer is formed. Note that the thickness of the EL layer formed here is desirably 100 nm to 1 μm.
[0243]
Note that the sample boat 1011 provided with the EL material may be changed together every time the type of the EL material is changed, or only the EL material may be exchanged without changing the sample boat.
[0244]
Here, the pixel column refers to a column of pixels partitioned by a bank (not shown), and the bank is formed above the source wiring. That is, a column in which a plurality of pixels are arranged in series along the source wiring is called a pixel column. Although the case where the bank is formed above the source wiring has been described here, it may be provided above the gate wiring. In this case, a column in which a plurality of pixels are arranged in series along the gate wiring is called a pixel column.
[0245]
Accordingly, the pixel portion (not shown) can be viewed as an aggregate of a plurality of pixel columns divided by a stripe bank provided above the plurality of source lines or the plurality of gate lines. When viewed in this manner, the pixel portion includes a pixel column in which a stripe-shaped EL layer that emits red light is formed, a pixel column in which a stripe-shaped EL layer that emits green light is formed, and a stripe shape that emits blue light. It can also be said that it consists of a pixel column in which the EL layer is formed.
[0246]
In addition, since the stripe-shaped bank is provided above the plurality of source wirings or the plurality of gate wirings, the pixel portion substantially includes a plurality of pixels divided by the plurality of source wirings or the plurality of gate wirings. It can also be viewed as a collection of columns.
[0247]
Further, a voltage is applied to the pixel electrode (anode) formed on the substrate 1010, and the vaporized EL material that has passed through the first mask and the second mask is further controlled to selectively select a desired position. It is preferable to apply an electric field for vapor deposition.
[0248]
In addition, in order to make the alignment between the first mask 1013 and the second mask 1019a accurate, two conductive plates are overlapped, and a slit-like or circular hole is simultaneously cut by electric discharge machining, so that the first mask 1013 and the first mask 1013 Two masks 1019a may be formed.
[0249]
In addition, the structure of a present Example can be implemented in combination freely with any structure of Example 1- Example 8. FIG.
[0250]
Example 10
In the present invention, an EL material (also referred to as a triplet compound) that can use phosphorescence from triplet excitons for light emission can be used. A self-light-emitting device using an EL material that can utilize phosphorescence for light emission can dramatically improve external light emission quantum efficiency. This makes it possible to reduce the power consumption, extend the life, and reduce the weight of the EL element.
[0251]
Here, a report of using triplet excitons to improve the external emission quantum efficiency is shown.
(T. Tsutsui, C. Adachi, S. Saito, Photochemical Processes in Organized Molecular Systems, ed. K. Honda, (Elsevier Sci. Pub., Tokyo, 1991) p.437.)
[0252]
The molecular formula of the EL material (coumarin dye) reported by the above paper is shown below.
[0253]
[Chemical 1]

[0254]
(MABaldo, DFO'Brien, Y.You, A.Shoustikov, S.Sibley, METhompson, SRForrest, Nature 395 (1998) p.151.)
[0255]
The molecular formula of the EL material (Pt complex) reported by the above paper is shown below.
[0256]
[Chemical 2]

[0257]
(MABaldo, S. Lamansky, PEBurrrows, METhompson, SRForrest, Appl.Phys.Lett., 75 (1999) p.4.) (T.Tsutsui, M.-J.Yang, M.Yahiro, K.Nakamura, T Watanabe, T.tsuji, Y.Fukuda, T.Wakimoto, S.Mayaguchi, Jpn.Appl.Phys., 38 (12B) (1999) L1502.)
[0258]
The molecular formula of the EL material (Ir complex) reported by the above paper is shown below.
[0259]
[Chemical 3]

[0260]
As described above, if phosphorescence emission from triplet excitons can be used, in principle, it is possible to realize an external emission quantum efficiency that is 3 to 4 times higher than that in the case of using fluorescence emission from singlet excitons.
[0261]
In addition, the structure of a present Example can be implemented in combination with any structure of Example 1- Example 9 freely.
[0262]
【The invention's effect】
By carrying out the present invention, it is possible to prevent the EL material from being deposited on the mask without passing through the mask when the EL material is deposited on the surface to be formed through the mask by the vapor deposition method. Furthermore, in the present invention, the alignment accuracy of the film formation position can be improved using a plurality of masks.
[0263]
Further, since the EL material can be prevented from being deposited on the mask by electrical repulsion, the mask can be used many times, and the EL material can be accurately formed without any problem of alignment accuracy. Therefore, the manufacturing yield of an EL display device using an EL material can be improved, and the cost can be reduced. Further, since the vapor deposition position of the vaporized EL material is controlled immediately before vapor deposition, the conventional vapor deposition method can be used, and a wide range of applications are possible.
[Brief description of the drawings]
FIG. 1 is a view showing a method for depositing an organic EL material of the present invention.
FIG. 2 illustrates a cross-sectional structure of a pixel portion.
FIG. 3 is a diagram showing a top structure and a configuration of a pixel portion.
4A and 4B illustrate a manufacturing process of an EL display device.
FIGS. 5A and 5B illustrate a manufacturing process of an EL display device. FIGS.
6A and 6B illustrate a manufacturing process of an EL display device.
FIG. 7 is a diagram showing a cross-sectional structure of a TFT in a pixel portion of an EL display device.
FIG. 8 illustrates a cross-sectional structure of a TFT in a pixel portion of an EL display device.
FIG 9 illustrates an appearance of an EL display device.
FIG. 10 is a diagram showing a circuit block configuration of an EL display device.
FIG. 11 illustrates a cross-sectional structure of an active matrix EL display device.
FIG. 12 is a view showing a vapor deposition pattern of an organic EL material.
FIG. 13 shows a mask pattern.
FIG 14 illustrates a cross-sectional structure of a passive EL display device.
FIG. 15 is a diagram showing a specific example of an electric appliance.
FIG. 16 is a diagram showing a specific example of an electric appliance.
FIG. 17 is a view showing a method for depositing an organic EL material of the present invention.

Claims (7)

Evaporate the EL material in the sample boat,
Charging the vaporized EL material;
Discharging the charged EL material from the sample boat;
A method for manufacturing an EL display device, wherein the EL material is selectively deposited on an electrode provided on a substrate by controlling an advancing direction of the EL material by an electric field. Evaporate the EL material in the sample boat,
Charging the vaporized EL material;
Discharging the charged EL material from the sample boat;
By passing the EL material through an opening of a mask to which a voltage that generates a charge repelling the charged EL material is applied, the traveling direction of the EL material is controlled by an electric field to be provided on the substrate. A method for manufacturing an EL display device, characterized by selectively depositing the EL material on an electrode. In claim 2 ,
The method for manufacturing an EL display device, wherein the mask includes a plurality of masks, and a position at which the EL material is deposited is controlled by controlling a voltage applied to each mask . In claim 2 or claim 3 ,
The mask is characterized in that a conductive line made of a conductive material , a mesh-like structure made of a conductive line, a plate-like structure made of a conductive material, or a plurality of conductive lines arranged in parallel to each other. A method for manufacturing an EL display device . In any one of Claims 1 thru | or 4,
A method for manufacturing an EL display device, wherein a position at which the EL material is deposited on the electrode is controlled by applying a voltage to the electrode. In any one of Claims 1 thru | or 5 ,
The method for manufacturing an EL display device, wherein the EL material is made of a low molecular material. In any one of Claims 1 thru | or 6 ,
The method for manufacturing an EL display device, wherein the film thickness of the EL material deposited on the electrode is 10 nm to 10 μm.

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