JPH02223189A - Manufacture of thin film el panel - Google Patents

Abstract

PURPOSE:To make it possible to form an EL luminescent layer with excellent crystallinity and without dead layer formation within a short period by forming a specified EL luminescent layer and forming another insulating layer on the luminescent layer. CONSTITUTION:A plurality of stripe transparent electrodes 12 on a glass substrate 11 and a first transparent insulating layer 13 is formed on the electrodes. An EL luminescent layer e.g. Mn-containing ZnS is formed by reciprocal exposure to vapors of metal Zn or Zn contained in Sr, Ca, and gaseous compound comprising H2S which is reactive with Zn at a prescribed temperature T1, or vapor of Zn prepared by decomposition of a gaseous compound by a decomposing means and a gas such as S2 which is prepared by thermal decomposition and reacts at the temperature lower than the prescribed temperature T1 and vapor of Mn become a luminescent center or TbOF. By this method, without deadlayer formation, an EL luminescent layer 14 with excellent crystallinity is formed within a short time.

Description

[Detailed Description of the Invention] [Summary] Regarding the manufacturing method of an 8M electroluminescent panel (thin film EL panel), a method for manufacturing an 8M electroluminescent panel (thin film EL panel), which produces an EL panel with good crystallinity that does not generate dead layers and does not contain halogen elements as impurities. For the purpose of forming a light emitting layer in a short time, in manufacturing a thin film EL panel in which an EL light emitting layer is sandwiched between insulating layers from both sides, one insulating layer formed on a substrate is heated to a predetermined temperature T1, and the 7. On the surface heated to a predetermined temperature TI, vapor of a metal element serving as a luminescent base material, and the metal element and a predetermined temperature 7. A gaseous compound that reacts as described above, or a thermally decomposed gas that reacts with the metal element obtained by decomposing the gaseous compound by a decomposition means at a predetermined temperature T1 or lower;
The EL light-emitting layer is formed by alternately and continuously exposing the element or vapor of the compound serving as the light-emitting center, and the other insulating layer is formed on the EL light-emitting layer.

[Industrial application field]

The present invention relates to a method of manufacturing an i-film EL (electroluminescent) panel, which is a type of flat display panel, and particularly relates to a method of manufacturing a thin-film EL panel with stable light emission characteristics and high brightness.

Thin film EL panels have very thin EL emitting layers and
, Y has a matrix structure, and the dimensional accuracy of the electrode film is good, so that the displayed image is clear and has excellent display quality without any blurring of light emission. Furthermore, it has features such as being able to easily achieve thinness and weight reduction and low power consumption, and has recently been applied to computer terminal displays and the like.

In manufacturing such thin-film EL panels, when forming an EL light-emitting layer, the crystallinity of the EL light-emitting layer may deteriorate depending on the formation method, resulting in a decrease in luminance, or there may be problems in the formed EL light-emitting layer. When a halogen element or the like is contained as an impurity, the light emitting characteristics tend to become unstable. For this reason,
There is a need for a method for manufacturing thin film EL panels with high brightness and stable light emitting characteristics.

[Conventional technology]

As shown in FIG. 4, a conventional thin film EL panel is made of indium oxide (Inks) and tin oxide (S) on a transparent glass substrate 1.
A plurality of transparent electrodes 2 with a film thickness of 2000 nm are formed in a stripe shape and are made of a solid state with a film of silicon oxynitride (hereinafter referred to as ITO) with a film thickness of 2000 nm.
A transparent first insulating layer 3 made of SiO, N, etc. is formed by a sputtering method or the like.

Further, on this first insulating layer 3, for example, a halogen compound consisting of manganese (Mn), which is the luminescent center, and zinc chloride (ZnCl□), which has a low vaporization temperature, which is the luminescent base material, and hydrogen sulfide (lhs) are used. Using the ALE (atomic layer epitaxy) method, a 4,000-layer thick EL light-emitting layer (
ZnS:Mn) 4 is formed on the surface thereof, and a transparent second insulating layer 5 made of silicon oxynitride (SiO2N, etc.) with a thickness of 2000 nm is formed on the surface thereof, and a matrix-like layer is formed perpendicularly to the transparent electrode 2. Aluminum (A ffi'
), etc., with a thickness of 2,500 stripes are successively laminated by sputtering or the like, and these laminated structures are covered with a moisture-proof protective film 7 made of an insulating resin material or the like.

Then, by selectively applying an AC voltage between any pair of electrodes in each electrode group of the upper and lower striped transparent electrodes 2 and the back electrode 6 that are orthogonal to the matrix, the EL light emitting layer 4 in that portion is applied. The display is performed by partially emitting light.

(Problems to be Solved by the Invention) In this conventional manufacturing method, the Et4 optical layer (ZnS:Mn) 4 is formed by combining manganese (Mn), which is the luminescent center, and manganese (Mn), which is the luminescent base material. Either an atmosphere with a halogen compound consisting of zinc chloride (ZnCl□), which has a low vaporization temperature, and an atmosphere of hydrogen sulfide (H2S) at room temperature are alternately exposed, or manganese (Mn), which is the luminescent center, and a luminescent base material are exposed. Zinc chloride (ZnCj!) has a low vaporization temperature.
This is because it is formed using the AL'E (atomic layer epitaxy) method, which forms a thin film by alternately exposing an atmosphere with a halogen compound consisting of , an EL light emitting layer with good crystallinity (ZnS:Mn
) is obtained, improving luminous brightness and luminous efficiency.

However, on the other hand, it has been found that halogen elements such as chlorine (Cj!z) remain as impurities in the formed EL light-emitting layer 4, and this impurity is activated by the electric field of the display drive pulse, and the light-emitting layer This has the disadvantage that unnecessary electronic levels are formed in the bandgap of the base material, causing fluctuations and deterioration of the luminescent properties.

In addition, an atmosphere of a halogen compound consisting of manganese (Mn), which serves as the luminescent center, and zinc chloride (ZnCl t), which serves as the luminescent base material and has a low vaporization temperature, and hydrogen sulfide (LS) at room temperature.
) When forming the light-emitting layer 4 by alternately exposing the substrate to an atmosphere, the ZnS layer cannot be formed unless the substrate temperature is maintained at at least 400°C.

Therefore, since the maximum temperature for practical heating and holding when using the glass substrate 1 is 400"C, the glass substrate heated to this temperature is alternately exposed to the Zn-containing atmosphere and the H, S atmosphere. When forming an EL light emitting layer, one H
, there is a problem that a thin film having a function as an EL light emitting layer cannot be easily formed unless the exposure time to the S atmosphere is set for a long time of one minute or more.

Furthermore, since residual or permeated HtS reacts with Zn just by touching the substrate, the atmosphere inside the film-forming chamber is A step is required to remove each atmosphere once. Therefore, it takes a long time of at least 50 hours to form an EL light-emitting layer with a thickness of 4,000 people, which is impractical in terms of manufacturing man-hours, and it is impossible to form an EL light-emitting layer at a low cost.

In view of the above-mentioned conventional drawbacks, the present invention provides a novel method for manufacturing a thin-film EL panel that can form an EL light-emitting layer with good crystallinity that does not generate dead layers and does not contain halogen elements as impurities in a short time. The purpose is to provide

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention, in manufacturing a thin-film EL panel in which an EL light-emitting layer is sandwiched between insulating layers from both sides, one insulating layer formed on a substrate is heated to a predetermined temperature T; On the surface heated to temperature T1, vapor of a metal element serving as a luminescent base material and a gaseous compound that reacts with the metal element at a predetermined temperature of 71 or higher, or the metal obtained by decomposing the gaseous compound by a decomposition means. The EL light-emitting layer is formed by alternately and continuously exposing the element to a gas produced by thermal decomposition that reacts at a predetermined temperature T or below, and to the vapor of the element or compound that becomes the luminescence center, and the EL light-emitting layer is The other insulating layer is formed on both sides.

[For production]

In manufacturing the thin film EL panel of the present invention, Zn vapor among the metal elements Zn and Sr+Ca is used as a luminescent base material,
A gaseous compound consisting of H and S that reacts with the Zn at a predetermined temperature 17 or higher, or a thermally decomposed gas such as 82 that reacts with the Zn obtained by decomposing the gaseous compound by a decomposition means at a predetermined temperature T or lower; Mn or T as the luminescent center
For example, ZnS containing Mn is exposed alternately to a vapor such as b0F.
Zn atoms and S
Since a ZnS crystal layer in which atoms are regularly arranged is formed, it not only eliminates the problem of dead layers with poor crystallinity in the light emitting layer, but also prevents halogen elements, which cause fluctuations and deterioration of light emitting characteristics, as impurities. Since there is no residual
A highly reliable thin film EL panel with high brightness and stable light emitting characteristics can be obtained.

In addition, Zn vapor, Mn vapor and Hz
Mn can be removed by thermal decomposition or by continuously and alternately exposing ionized decomposition gas.
The crystal growth rate of ZnS containing
Compared to the formation of an EL light emitting layer by the method, the time required for formation is dramatically shortened (M at least 172 or less), and costs can be reduced.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 1(a) and 1(b) are sectional views of main parts sequentially showing one embodiment of a method for manufacturing a thin film EL panel according to the present invention.

First, as shown in FIG. 1(a), I was deposited on a transparent glass substrate 11 by sputtering and photoetching.
A plurality of strip-shaped transparent electrodes 12 having a film thickness of 2000 mm are formed from a TO film, and on the surface thereof, for example, a CVD method using raw materials of aluminum chloride (Af(J,) and water (HzO)), or Alumina (Af□(h) film and titanium oxide (TiO
t) Form a transparent first insulating layer 13 made of N or the like and having a thickness of 2500 nm.

Next, the glass substrate 11 with the first insulating layer 13 formed thereon is placed in a resistance heating type Zn evaporation source 22, Mn evaporation source 23, and heater 25 installed in a sealed container 21 of a vacuum evaporation apparatus shown in FIG. The inside of the sealed container 21 is heated to 2×10 −6 to
While evacuating to a vacuum level of rr, the glass substrate 11 on which the first insulating layer 13 is formed is heated to 400° C. by the heater 26.

And the Zn vapor deposition source 22 and the Mn vapor deposition source 23 facing each other
Zn vapor and M evaporate by heating respectively
n steam, 1 (H2S in the IS pyrolysis cell 24)
is thermally decomposed at 900°C, and the outflow amount is controlled to be 10105e by a mass flow controller (not shown) to flow out mainly S2 and H! By alternately exposing the surface of the first insulating layer 13 on the heated glass substrate 11 for 2 seconds each by controlling the opening and closing of the shutters 28 and 29 and the gas opening/closing pulp 30, the decomposition product gas consisting of An EL light emitting layer (ZnS:Mn) 14 containing an impurity mainly made of manganese (Mn) is formed.

The above three types of Zn vapor, Mn vapor, S2 and 11□
One cycle of alternately exposing the decomposition product gas consisting of ZnS: Mn)14 can be formed.

After that, as shown in FIG. 1(b), the EL light emitting layer (Z
A transparent second insulating layer 15 made of the same material and having a thickness of 2,500 mm is formed on the first insulating layer 13 by the same method as the first insulating layer 13 described above. Aluminum (A j
2) A striped back electrode 16 is formed by vapor deposition and photoetching processes. Then, these laminated structures are coated with a moisture-proof protective film 17 made of an insulating resin material, etc.
Cover and complete.

In addition, the vapor pressure of the decomposition product gas consisting of S2 is 80°
The decomposed gas which does not contribute to the formation of the EL light-emitting layer 14 is fixed in contact with the inner wall of the sealed container 21, so it does not float inside the sealed container 21, and the Zn The vapor pressure of S2 and Mn is lower than that of S2, and like the decomposition gas, they do not float in the sealed container 21, so the three types of Znfg and Mn
When alternately exposing steam and decomposition product gas consisting of S2 and H2, the sealed container 2 is closed each time the exposed steam or gas is changed.
Even if unnecessary vapors or gases are not removed, the vapors or gases will not interfere or react with each other.

In addition, in this embodiment, 11 in the H,S pyrolysis cell 24
The reason why the thermal decomposition temperature of 2S is set at 900'C is that, for example, HzSO thermal decomposition starts at 550'C or higher, and
Below °C, S is not produced and only 32 is produced. Since the vapor pressure of S is as low as that of ZnS, it tends to stick in the layer film by itself, making the stoichiometric bond of ZnS excessive, which reduces its crystallinity. In the example, as mentioned above, S is not generated, and Zn vapor and Mn
The decomposed gas consisting of steam and S2 is alternately applied to the glass substrate 1.
Since the film is formed by exposing the surface of the first insulating layer 13 on the first insulating layer 13,
A crystal layer in which Zn atoms and Mn atoms and 32 molecules are regularly arranged is formed, so there is no generation of dead layers.
A ZnS film with good crystallinity, that is, the EL light emitting layer 14 can be obtained.

Others, H! By setting the thermal decomposition temperature of S to 900''C, it is possible to construct the cell for H,S thermal decomposition using silicon (St), which does not evaporate at around 1000°C, has good processability, is inexpensive, and has high purity. can.

Further, in this embodiment, an example has been described in which the th2S gas is heated to 900'C, decomposed, and introduced into the sealed container in which the substrate is placed, but the temperature may be, for example, closer to 550'C. However, as the temperature decreases, the time for which the substrate is exposed to the decomposition gas consisting of S2 and 11□ must be increased, and it tends to take a long time to form a light-emitting layer. lhs in the cell for
Instead of the heater 25 described above as a means for thermally decomposing gas, a pair of opposing electrodes is provided in the cell, a high voltage is applied between the electrodes, and the ionized decomposition gas flows out.
It may be exposed to the substrate surface.

Incidentally, the thin film EL panel manufactured according to this example was
When driven at an emission dark value voltage of +30V, a pulse width of 25 us, and 60 Hz, a high brightness of 70 fL was obtained, and as a result of an accelerated life test performed for 60 hours at 10 kHz, no decrease in emission brightness was observed. It was confirmed that there was no change in luminescent characteristics.

FIGS. 3(a) and 3(b) are schematic configuration diagrams showing a vacuum evaporation apparatus applied to another embodiment of the method for manufacturing a thin film EL panel according to the present invention, and FIG. 3(a) is a plan view, and FIG. b) is a sectional view of the structure.

In this example, a plurality of striped transparent electrodes with a thickness of 2,000 layers made of ITO film and alumina (A
FIG. 3(a) shows a plurality of glass substrates 11 on which transparent first insulating layers having a thickness of 2,500 mm are sequentially formed, such as a titanium oxide (TiO□) film or a titanium oxide (TiO□) film.

As shown in (b), the resistive heating type Zn evaporation source 22, Mn evaporation source 23, and H2S pyrolysis cell 24, which are installed in a sealed container 21 of a vacuum evaporation apparatus and separated by a partition wall 31, are commonly faced. It has a built-in heater 33 and is placed on a rotatable substrate support 32.

Next, the inside of the sealed container 21 is evacuated to a degree of vacuum of 2×10− &torr, and the plurality of glass substrates 11 are heated to 400′C by the built-in heater 33.

Then, while the substrate support 32 is rotated at a rotational speed of, for example, 3 rpra, the Zn vapor deposition source 22 and the Mn vapor deposition source 23 are heated by a resistance heating method to evaporate Zn vapor and Mn vapor, and ths thermal decomposition source The H2S gas introduced into the cell 24 is thermally decomposed at 900°C by the heater 25, and then heated to 10°C by a mass flow controller (not shown).
S2 and 11□ were controlled to flow out at the flow rate of 105e.
By alternately exposing the surface of each first insulating layer on the plurality of rotating glass substrates to a decomposition product gas consisting of ZnS:Mn) is formed.

In this embodiment, the glass substrate 11 is sequentially moved onto three types of Zn vapor, Mn vapor, and decomposition product gas consisting of St and H2, and is continuously and alternately exposed to it, which is extremely efficient. It becomes possible to form an EL light emitting layer.

Incidentally, 10 substrates were mixed with three types of Zn vapor, Mn vapor, and S.
Each glass substrate 11 was exposed to a decomposition product gas of 4,000 t and H2 for 20 seconds each cycle.
When forming an EL light-emitting layer with a thickness equal to that of a human, the time required to form the EL light-emitting layer per substrate can be significantly shortened to 50 minutes.

Thereafter, a transparent second insulating layer made of the same material and having a thickness of 2,500 mm is formed on the above-mentioned EL light emitting layer by the same formation method as the first insulating layer, and on the surface of the second insulating layer, an aluminum layer perpendicular to the transparent electrode is formed. A striped back electrode made of (A N ) or the like is formed, and the laminated structure is further covered with a moisture-proof protective film made of an insulating resin material or the like to complete the process.

The thin-film EL panel obtained by the manufacturing method of this embodiment also has the same effects as the thin-film EL panel obtained by the embodiments shown in FIGS. 1(a), 2(b) and 2.

Note that Zn was used to form the EL light emitting layer in the above examples.
Although an example has been described in which a vacuum evaporation apparatus is used in which the evaporation source, the Mn evaporation source, and the H, S pyrolysis cell are separated by a partition wall, a sputtering apparatus with a similar configuration may be used.

[Effects of the Invention] As is clear from the above description, the thin film EL according to the present invention
According to the manufacturing method of the panel, the problem of dead layer formation in the EL light emitting layer is solved, there is no fear of impurities such as halogen elements being included, and the panel is highly reliable with high brightness and stable light emitting characteristics. It has an excellent advantage of being able to produce thin film EL panels in a short time, and is extremely advantageous when applied to the production of this type of thin film EL panels.

[Brief explanation of the drawing]

1(a) and 1(b) are sectional views of main parts for sequentially explaining one embodiment of the method for manufacturing a thin film EL panel according to the present invention, and FIG. 2 is a method for manufacturing a thin film EL panel according to the present invention. FIG. 3(a), Φ) is a schematic configuration diagram showing a vacuum evaporation apparatus applied to one embodiment, and FIG. FIG. 4 is a configuration diagram, in which FIG. 4A is a plan view, FIG. 1 (a), (b) to 3 (a), (b) 11 is a glass substrate, 12 is a transparent electrode, 13 is a first insulating layer, 14 is an EL light emitting layer, 15 is a Second insulating layer, 16 is a back electrode, 17 is a moisture-proof protective film, 21 is a sealed container, 22 is a Zn evaporation source, 23 is a Mn evaporation source, 24 is a HtS pyrolysis cell, 25.27.33+b) 4 ra Pus EL 8' FL 4 η Cage 1 ≦ Dofu Scarcity ε Mouse V Ming O
07p 100σs 1 Zuhon 46θ ear/1'5Li force) ゑ1-9geL, UZEN'Z4
Figure 2 shows a heater, 26 and 32 a substrate support, 28 and 29 a shutter, 30 an opening/closing valve, and 31 a separation wall. (Q) (b) 2 to the sun and the moon n1A" and free E4t + 3 eyebrows rainbow's hona 4ku (1ji surprise to °5 fig. 3

Claims (4)

[Claims] (1) Cover the EL light emitting layer (14) with the insulating layers (13, 14) from both sides.
15), one of the insulating layers (13) formed on the substrate (11) is heated to a predetermined temperature T_1, and a light emitting layer is placed on the surface heated to the predetermined temperature T_1. A gaseous compound that reacts with the vapor of a metal element serving as a base material at a predetermined temperature T_1 or higher, or a thermal decomposition product that reacts with the metal element obtained by decomposing the gaseous compound by a decomposition means at a predetermined temperature T_1 or lower. The EL light emitting layer (14) is formed by alternately and continuously exposing the gas and the vapor of the element or compound that is the center of light emission.
is formed, and the other insulating layer (
15) A method for manufacturing a thin film EL panel, comprising: (2) The method for manufacturing a thin film EL panel according to claim 1, wherein the metal element is made of one of Zn, Sr, and Ca, and the gaseous compound is made of H_2S. (3) A claim characterized in that the means for decomposing the gaseous compound is thermal decomposition using a heater provided in a pyrolysis cell, or ionization decomposition by applying a high electric field to a counter electrode provided in the cell. Item 1. A method for manufacturing a thin film EL panel according to item 1. (4) A method in which the surface of one of the insulating layers (13) is alternately exposed to the vapor of the metal element, the gaseous compound or gas produced by thermal decomposition, and the vapor of the element or compound that is the center of luminescence. 2. The method of manufacturing a thin film EL panel according to claim 1, wherein the surface of one insulating layer (13) is sequentially moved over each vapor evaporation region and gas outflow region.