JP2009117663A - Storing method, transporting method and storage device for substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a storing method, a transporting method and a storage device, such that a substrate having an organic functional layer can be stored using a more inexpensive device. <P>SOLUTION: Disclosed is the storing method for the substrate having the organic functional layer, the storing method being characterized in that the substrate having the organic functional layer is stored in an inert liquid, which is preferably (1) chemically inactive and does not chemically react with a compound constituting the organic functional layer, (2) liquid at room temperature, and (3) has a vapor pressure of ≥5,000 Pa at room temperature. Also disclosed is the transporting method to which the storing method is applied. Further, disclosed is the substrate storage device having a chamber 101 which can store the substrate having the organic functional layer and can be sealed, the inert liquid 102 contained in the chamber 101, and means 103 and 104 for putting the inert liquid 102 in and out of the chamber 101. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method and apparatus for storing or transporting a substrate provided with an organic functional layer.

In recent years, organic functional elements such as organic EL elements using organic functional materials, organic solar cells, and organic functional layer transistors have been actively developed with the aim of reducing the weight and flexibility of electronic components. Yes.
As such an organic functional material, a π-electron organic functional material is widely used (for example, Non-Patent Document 1).

Such a compound has a high possibility of causing a chemical reaction with oxygen or water and deteriorating device characteristics.
In particular, oxygen is likely to be a reactive oxygen species such as excited singlet oxygen or superoxide anion having high reactivity due to heat or light, and may cause a reaction with a double bond site of a π-electron molecule.

  Therefore, when handling an organic functional material, it is often necessary to carry out under an inert atmosphere such as nitrogen or argon. In particular, it is preferable to perform in an inert atmosphere when heating or when storing for several hours or more even at room temperature.

Similarly, it is known that a semiconductor substrate deteriorates due to light, oxygen, and water.
In order to solve this problem, a method of storing a substrate in a vacuum or an inert gas atmosphere (Patent Documents 1 to 5), an inert liquid (Patent Document 6), or a light shielding condition (Patent Document 7) has been proposed. ing.

However, in order to create a vacuum state, it is necessary to make the chamber a pressure-resistant structure or to prepare a vacuum pump, which increases the cost of the apparatus. Also, once through the vacuum state, dust may rise and adhere to the substrate during venting.
In addition, in order to create an inert gas atmosphere, it is necessary to replace the gas, and it is necessary to create a vacuum once, or to flow a very large amount of inert gas, or to use a high-performance gas purifier. is there.
In order to create a vacuum state, a pressure-resistant chamber and a vacuum pump are required as described above, and the apparatus cost is high. Further, when the inert gas is allowed to flow down, the running cost is high.
In addition, when using a high-performance gas purifier, it is necessary to either purify after vacuuming and then purify with nitrogen, or suddenly purify from atmospheric conditions, but in the former case a vacuum is necessary. In the latter case, it takes time in units of several hours until the inside of the chamber becomes an inert gas atmosphere, and the substrate may deteriorate during that time.

  In the light shielding method, the photoinduced electron transfer reaction and the photoinduced energy transfer reaction can be suppressed, but the reaction due to heat cannot be suppressed. Even if the reaction rate at room temperature is very slow, it is not sufficient as a storage environment to simply block light when assuming long-term substrate storage.

In the method disclosed in Patent Document 6 (Japanese Patent Laid-Open No. 5-218174), a vacuum chamber is described because it is connected to a semiconductor substrate manufacturing apparatus. However, the substrate itself is stored in a group 0 noble gas or liquid. It is done with active gas. In addition, the liquid inert gas said in this literature has shown the fluorine compound which is a gas at normal temperature, and is a liquid at 0 degrees C or less, the liquid of carbon monoxide or a dicarbon dioxide, liquid nitrogen, etc.
When the rare gas is used, the cost is high because it is the same as the above-described inert gas atmosphere.
On the other hand, when using a liquid inert gas, it is not necessary to create a vacuum environment, but since it is a gaseous liquid at room temperature, it is necessary to devise measures such as covering the chamber with a heat insulating material. In addition, it is not suitable for long-term storage because it must keep the low temperature. Further, when liquid carbon dioxide is used, it is necessary to apply a pressure of about 0.5 MPa or more. When using carbon monoxide, there is a high risk of toxicosis.

  Regarding the substrate carrying the organic functional material, it is preferable to store in an inert gas atmosphere as in the case of the semiconductor substrate. Therefore, the above-described storage device for a semiconductor substrate can be used.

However, since the storage means described above is expensive in apparatus and running cost, it is not preferable in view of providing inexpensive products.
JP-A-5-259445 JP-A-5-243116 JP 11-168135 A JP 2005-340330 A JP 2002-117759 A Japanese Patent Laid-Open No. 5-218174 International Publication WO01 / 048813 Pamphlet “Quarterly Review of Chemical Chemistry 35 π Electron Organic Solids”, 1998, The Chemical Society of Japan

  Then, this invention is made | formed in view of this situation, and makes it a subject to provide the method, the conveyance method, and storage apparatus which can store the board | substrate provided with an organic functional layer with a cheaper apparatus.

  The present invention has been made in view of the above-mentioned problems, and preferably, the above-mentioned problems are solved by using a solvent (inert liquid) that is highly volatile and chemically inert at room temperature. I found what I could do.

  The invention according to claim 1 is a method for storing a substrate, characterized in that the substrate having the organic functional layer is stored in an inert liquid.

The invention according to claim 2 is characterized in that the inert liquid is
(B) It is chemically inert and does not cause a chemical reaction with the compound constituting the organic functional layer.
(B) The substrate storage method according to claim 1, wherein the substrate is liquid at room temperature and (c) has a vapor pressure of 5000 Pa or more at room temperature.

  In the invention according to claim 3, when the organic functional layer is immersed in the inert liquid, the surface of the organic functional layer 24 hours after being immersed in the surface roughness Ra of the organic functional layer before immersion. The change rate of roughness Ra is less than 1%, and the weight of the organic functional layer dissolved in the inert liquid after 24 hours is less than 0.1% of the weight of the organic functional layer before immersion. The substrate storage method according to claim 1, wherein a liquid that satisfies the condition is used as the inert liquid.

  The invention according to claim 4 is the substrate storage method according to any one of claims 1 to 3, wherein the inert liquid is a compound containing five or more fluorine atoms in one molecule. It is.

  According to a fifth aspect of the present invention, there is provided a substrate transporting method which transports the substrate while applying the substrate storage method according to any one of the first to fourth aspects.

  The invention described in claim 6 is a chamber capable of storing and sealing a substrate having an organic functional layer, an inert liquid stored in the chamber, and the inert liquid being put into and out of the chamber. A substrate storage device.

  The invention described in claim 7 is the substrate storage apparatus according to claim 6, comprising means for removing impurities contained in the inert liquid.

  The substrate storage according to claim 7, wherein the impurity is a solid impurity, and the means for removing the solid impurity is a filter for filtering the solid impurity. Device.

  The invention according to claim 9 is an active gas in which the impurity is dissolved in an inert liquid, and the means for removing the impurity is a replacement means by bubbling of an inert gas or ultrasonic or liquid heating. The substrate storage device according to claim 7, wherein the substrate storage device is a degassing unit.

  The invention according to claim 10 is characterized in that the impurity is a liquid impurity, and the means for removing the liquid impurity is a filter or a distillation apparatus for filtering the liquid impurity. This is a substrate storage device.

The invention according to claim 1 is a method for storing a substrate, characterized in that a substrate comprising an organic functional layer (hereinafter referred to as a substrate) is stored in an inert liquid. Can be stored in the device.
According to the invention described in claim 2, by specifying the inert liquid, the organic functional material on the substrate (the material contained in the organic functional layer) is not deteriorated by a chemical reaction. Further, since the inert liquid is a liquid at normal temperature, it is not necessary to cool the storage device, and it is possible to introduce the inert liquid into the chamber without having to evacuate the chamber once. In the prior art, when an active gas such as oxygen remains in the chamber, even if an inert gas is introduced into the chamber, it is mixed with the active gas and it is not easy to completely replace the gas. . Therefore, it is necessary to remove the active gas once as a vacuum. On the other hand, when an inert liquid is introduced as in the present invention, mixing with an active gas hardly occurs, and the periphery of the substrate can be quickly switched to an inert atmosphere without going through a vacuum state. In addition, when the substrate after storage is taken out of the chamber, the vapor pressure at room temperature is high and the volatility is high. Therefore, it is possible to take out the dried substrate without performing draining.
According to the third aspect of the invention, since the conditions for the inert liquid are further specified, the organic functional material is not dissolved, and the substrate is stored without changing the structure of the organic functional layer.
According to the invention described in claim 4, since the inert liquid is a compound containing five or more fluorine atoms in one molecule, the organic functional material does not dissolve and the structure of the organic functional layer does not change. The effect is further enhanced.
The invention according to claim 5 is a substrate transport method characterized in that the substrate is transported while applying the substrate storage method according to any one of claims 1 to 4. In addition, the substrate can be transported while maintaining the effects that the organic functional material does not dissolve and the structure of the organic functional layer does not change.
According to the sixth aspect of the present invention, a chamber capable of storing and sealing a substrate having an organic functional layer, an inert liquid stored in the chamber, and the inert liquid in and out of the chamber. Therefore, the substrate can be stored while maintaining the effects that the organic functional material does not melt and the structure of the organic functional layer does not change. Even if the apparatus is not sealed, if the substrate is immersed in an inert liquid, the organic functional layer on the substrate is unlikely to deteriorate. And volatilization of the inert liquid can be suppressed.
Moreover, according to the substrate storage apparatus described in claims 7 to 10, impurities mixed in the inert liquid can be easily removed.

Hereinafter, the present invention will be described in more detail.
First, the inert liquid that can be used in the present invention will be described. The inert liquid preferably satisfies the following three requirements.
(B) It is chemically inert and does not cause a chemical reaction with the compound constituting the organic functional layer.
(B) It is liquid at room temperature, and (c) has a vapor pressure of 5000 Pa or more at room temperature.
The normal temperature here means 25 ° C.
As such an inert liquid, when the organic functional layer is immersed in the inert liquid, the surface roughness of the organic functional layer 24 hours after being immersed in the surface roughness Ra of the organic functional layer before immersion. The change rate of the thickness Ra is less than 1%, and the weight of the organic functional layer dissolved in the inert liquid after 24 hours is less than 0.1% of the weight of the organic functional layer before immersion. A filling liquid is preferred.
More preferably, it is a compound containing 5 or more fluorine atoms in one molecule.
Table 1 below illustrates inert liquids that can be particularly preferably used in the present invention.

  Next, embodiments of the present invention will be described in more detail with reference to the drawings.

The chamber 101 shown in FIG. 1 can store an inert liquid 102, a substrate (not shown), and a substrate holder therein.
The chamber 101 needs to be able to be sealed so that the inert liquid 102 and the gas vaporized from the chamber 101 do not leak out and impurities are not mixed from the outside. Since it is not necessary to withstand decompression or pressurization, the wall thickness of the chamber does not have to be thick, and the material can be any material that does not elute impurities and can withstand the weight of the inert liquid 102 and the substrate and substrate holder. Can be selected. Specifically, a metal that is not easily corroded, such as SUS and anodized aluminum, or a material in which the surface of the metal is coated with a fluororesin can be preferably used.
The lid for taking in and out the substrate and the substrate holder can be freely arranged on the upper side or the side surface in accordance with the substrate transport mechanism. In addition, an internal chamber 108 may be installed in the chamber 101 as shown in FIG. In particular, when a lid is installed on the side surface of the chamber 101, it is possible to preferably use the method shown in FIG.
In that case, the substrate can be taken out from above after sliding the internal chamber 108 in the lateral direction.

  The chamber 101 is connected to an inert liquid injection valve 103 for containing the inert liquid 102 and an inert liquid discharge valve 104 for taking out the inert liquid 102 to the outside.

The atmosphere remaining in the chamber 101 may be a problem. It is also possible to introduce an inert gas to replace the atmosphere. As the inert gas, a chemically inert gas such as nitrogen or argon can be used. The inert gas is introduced via the inert gas injection valve 105 when replacing the atmosphere inside the chamber 101 with the atmosphere. Further, when replacing with a chemically active gas such as oxygen dissolved in the inert liquid 102, the gas is introduced via a bubbling inert gas injection valve 106.
The introduction of the inert gas in the present invention is different from the case of replacing the entire chamber interior with the inert gas, and the main purpose is to replace the air in a slight gap where the inert liquid 102 does not exist. Does not require active gas. Further, since the substrate is covered with the inert liquid 102, it is not necessary to perform strict replacement. Therefore, replacement with a vacuum pump and purification with a high-performance gas purifier are unnecessary.
An inert gas discharge valve 107 and a check valve are installed in order to let the inert gas introduced into the chamber out of the chamber.

This inert gas is also taken in and out to maintain the pressure in the chamber when the inert liquid in the chamber is taken in and out.
Specifically, when an inert liquid is introduced into the chamber, the gas is extracted from the inert gas discharge valve in order to prevent the internal pressure from increasing. At that time, since the gas is pushed out by the inert liquid, it is not necessary to dare to extract the gas with a pump.
Further, when the inert liquid is extracted from the chamber, gas is introduced from an inert gas injection valve in order to prevent the internal pressure from being lowered. In order to smoothly discharge the liquid, it is possible to push out the liquid by slightly increasing the pressure of the gas. In that case, the cracking pressure of the check valve may be set slightly higher.

The inert liquid discharged from the inert liquid discharge valve 104 is subjected to impurity removal treatment as necessary. An example of the processing apparatus is as shown in FIG.
In FIG. 3, the inert liquid is sucked by the liquid recovery pump 306 and separated from solid impurities such as dust and dust by the dust filter 305. The filtered inert liquid is temporarily stored in the inert liquid storage container 301. The inert liquid is conveyed by the liquid injection pump 308, and after removing solid impurities and moisture by the dust filter 309 and the moisture removal filter 310, the inert liquid is introduced again into the chamber 101.
Chemically active gases such as oxygen mixed in the inert liquid due to atmospheric exposure can be removed by cavitation degassing processing by the ultrasonic generator 303 or bubbling processing by the inert gas injection valve 307 for bubbling. It is. In addition, heating the inert gas with the heater 304 is also effective for the degassing process.
When a solvent other than the inert liquid is mixed in the inert liquid, the distillation treatment may be performed by a distillation purifier (not shown).

Since the apparatus of the present invention does not use a vacuum system and does not use a large amount of inert gas, it can be produced at a very low cost, and the running cost can be kept low.
Moreover, since pressure resistance is not required, it is possible to reduce the weight, and it can be used for storing a large number of substrates by arranging a number of chambers in parallel, and an apparatus as shown in FIG. A set can be incorporated into a mobile cradle to transport the substrate to the desired location.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

<Examples of organic EL elements>
In FIG. 4, a substrate with ITO 402 on a glass substrate 401 was prepared, and the ITO was etched into a predetermined pattern. Next, a liquid in which a mixture of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid is dispersed in water as an electron transporting layer coating solution on the etched transparent conductive layer by a letterpress printing method. It was applied in a pattern on the substrate. This substrate was dried at 200 ° C. for 3 minutes in the air to obtain a hole transport layer 403a. The thickness after drying was 50 nm.

  Further, a toluene solution of poly (2- (2-ethylhexyloxymethoxy) -5-methoxy-1,4-phenylenevinylene), which is a polyarylene vinylene polymer light emitting material, is used as a coating solution for the light emitting layer. After spin coating, heat treatment was performed on a hot plate at 130 ° C. for 10 minutes to obtain a 100 nm light emitting layer 403b. This process was performed in a glove box having an oxygen concentration of 1 ppm and a dew point of -70 ° C.

  Further, after the substrate provided with the organic functional layer 403 was subjected to the storage process described in Example 1 and Comparative Examples 1, 2, and 3, lithium and aluminum were provided as the cathode 404 by 0.5 nm and 200 nm, respectively, by vacuum deposition. Thus, an organic EL element was obtained. Hereinafter, the production results of each example will be mainly described.

Example 1
In the storage apparatus shown in FIG. 3, the substrate was stored for one week using nonafluorobutyl methyl ether as the inert liquid and argon as the inert gas. While monitoring the oxygen concentration contained in the gas in the dead space in the chamber as needed, argon was injected from the inert gas injection valve for bubbling whenever the concentration reached 1000 ppm or more. The substrate taken out of the chamber was subjected to a vacuum deposition process without any particular treatment.

When a voltage of 8 V was applied to the obtained organic EL element, it showed patterned luminescence of 100 cd / m ² . Further, when the luminance half-life at the time of constant current driving was measured at an initial luminance of 100 cd / m ² , the luminance half-life was 3000 hr.

(Comparative Example 1)
The substrate was stored in a high vacuum chamber of 0.01 mPa for one week. Then, the vacuum evaporation process was implemented.

When a voltage of 8 V was applied to the obtained organic EL element, it showed patterned luminescence of 100 cd / m ² . Further, when the luminance half-life at the time of constant current driving was measured at an initial luminance of 100 cd / m ² , the luminance half-life was 3000 hr.

(Comparative Example 2)
The substrate was put into a vacuum chamber, and evacuation and high-purity nitrogen vent were repeated so that the oxygen concentration was less than 1000 ppm. This replacement step was repeated each time the oxygen concentration increased and stored for one week. The substrate taken out of the chamber was subjected to a vacuum deposition process without any particular treatment.

When a voltage of 8.5 V was applied to the obtained organic EL device, it showed patterned luminescence of 100 cd / m ² . Further, when the luminance half-life at constant current driving was measured at an initial luminance of 100 cd / m ² , the luminance half-life was 2000 hr. However, dark spots that appear to be caused by the dust that soared in the chamber due to repeated substitutions adhered to the substrate surface were generated in some light emitting cells.

(Comparative Example 3)
The substrate was placed in a sealed container made of SUS and left in the atmosphere for one week. After the substrate was air blown, a vapor deposition process was performed.

When a voltage of 9 V was applied to the obtained organic EL element, it showed patterned luminescence of 100 cd / m ² . Further, when the luminance half-life at the time of constant current driving was measured at an initial luminance of 100 cd / m ² , the luminance half-life was 1000 hr.

It is a schematic diagram of the board | substrate storage apparatus in this invention. It is a schematic diagram of the board | substrate storage apparatus in this invention. It is a schematic diagram of the board | substrate storage apparatus in this invention. It is sectional drawing of an example of the organic EL element in this invention.

Explanation of symbols

101: chamber 102: inert liquid 103: inert liquid injection valve 104: inert liquid discharge valve 105: inert gas injection valve 106: inert gas injection valve 107 for bubbling 107: inert gas discharge valve 108: internal chamber 301 : Inert liquid storage container 302: inert liquid 303: ultrasonic generator 304: heater 305: dust filter 306: liquid recovery pump 307: inert gas injection valve for bubbling 308: liquid injection pump 309: dust filter 310: moisture Removal filter 401: Glass substrate 402: ITO
403: Organic functional layer 403a: Hole transport layer 403b: Light emitting layer 404: Cathode

Claims (10)

  A substrate storage method comprising storing a substrate having an organic functional layer in an inert liquid. The inert liquid is
(B) It is chemically inert and does not cause a chemical reaction with the compound constituting the organic functional layer.
(B) The substrate storage method according to claim 1, wherein the substrate is liquid at room temperature and (c) has a vapor pressure of 5000 Pa or more at room temperature.   When the organic functional layer is immersed in the inert liquid, the change rate of the surface roughness Ra of the organic functional layer after 24 hours from the immersion to the surface roughness Ra of the organic functional layer before immersion is 1%. The liquid satisfying that the weight of the organic functional layer dissolved in the inert liquid after 24 hours is less than 0.1% of the weight of the organic functional layer before immersion is defined as the inert liquid. The substrate storage method according to claim 1, wherein the substrate storage method is used.   The method for storing a substrate according to any one of claims 1 to 3, wherein the inert liquid is a compound containing five or more fluorine atoms in one molecule.   5. A substrate transport method, wherein the substrate is transported while applying the substrate storage method according to claim 1.   Substrate storage comprising: a chamber capable of storing a substrate having an organic functional layer and capable of being sealed; an inert liquid stored in the chamber; and means for putting the inert liquid in and out of the chamber. apparatus.   The substrate storage apparatus according to claim 6, further comprising means for removing impurities contained in the inert liquid.   The substrate storage apparatus according to claim 7, wherein the impurity is a solid impurity, and the means for removing the solid impurity is a filter that filters the solid impurity.   The impurity is an active gas dissolved in an inert liquid, and the means for removing the impurity is a replacement means by bubbling of an inert gas or a degassing means by ultrasonic or liquid heating. The substrate storage apparatus according to claim 7.   8. The substrate storage device according to claim 7, wherein the impurity is a liquid impurity, and the means for removing the liquid impurity is a filter or a distillation apparatus for filtering the liquid impurity.

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