KR102035813B1 - Deposition method and device - Google Patents

Abstract

The present invention first relates to a method for depositing a layer of organic starting material on a substrate (11), which is sent inside the evaporator (1) in a carrier gas stream as an aerosol in the form of suspended particles, The suspended particles are there in contact with the heat transfer face 15 heated by the temperature control device and evaporate after an average residence time which also depends on the temperature of the heat transfer face 15 and by means of a carrier gas as described above The generated steam exits the evaporator 1 as output gas flow and is sent into the process chamber 10 where steam condenses while forming a layer on the surface of the substrate 11. In order to reduce the time-varying rate of steam generated by evaporation of the aerosol, according to the present invention the temperature of the heat transfer face 15 depends on the time-dependent change in the mass flow of steam c generated in the output gas stream. It is proposed to change in response. The invention also relates to an apparatus for evaporating organic suspended particles transported in a carrier gas stream, and an apparatus for depositing OLEDs.

Description

Deposition Method and Apparatus {DEPOSITION METHOD AND DEVICE}

The present invention relates to a method for depositing a layer of organic starting material on a substrate, in which case the organic starting material is sent into the evaporator by a carrier gas flow as an input gas stream in the form of suspended particles, in which case the The suspended particles come into contact with the heated heat transfer face there and evaporate after an average residence time depending on the temperature of the heat transfer face, in which case the steam generated by the carrier gas as above is discharged from the evaporator as the output gas flow. It exits and is sent into the process chamber, where the vapor condenses, forming a layer on the surface of the substrate.

The invention also provides an apparatus for evaporating organic suspended particles transported in a carrier gas stream, i.e. formed in the form of a container having therein an inlet opening for an input gas flow, an outlet opening for an output gas stream and a heat transfer face therein. Also associated with the device, in which case the heat transfer face is caused by a fluctuating heating energy flow, from which the suspended particles sent into the vessel through the inlet opening come into contact with the heat transfer face from the vessel through the outlet opening. It may be heated to a temperature which is evaporated with the exiting organic vapors.

The present invention further relates to an apparatus for depositing an OLED having such an evaporator as described above.

US 7,238,389 B2 describes a method of the same kind to a device of the same kind. In this publication aerosols are generated by an aerosol-generator. Aerosols consist of powder sent into the carrier gas stream. Aerosol particles are sent from the aerosol-generator to the evaporator by carrier gas flow as suspended particles. The evaporator consists of a solid foam that is heated to the evaporation temperature. Evaporative heat is provided to the suspended particles by surface contact of the suspended particles with the pore walls of the solid foam. The evaporation rate depends on the temperature of the heat transfer side. If the process is carried out below the saturation range, the mass per unit time of the organic starting material fed to the evaporator corresponds to the mass per unit time of steam sent out from the evaporator. The various temperatures occurring in a particular region result in only different average residence times of the unvaporized organic starting material actually in the evaporator. The vapor generated in this way is supplied into the process chamber by a carrier gas, and a substrate exists in the process chamber. The substrate is coated with an organic starting material. In the simplest case, the substrate should only be maintained at the corresponding low temperature, as a result of which vapor is deposited as a condensate on the substrate surface.

US 2009/0039175 A1 also describes the use of solid foams or coated materials, especially consisting of tungsten, rhenium, tantalum, niobium, molybdenum or plastics, to evaporate organic starting materials.

US 6,037,241 describes a solid evaporator having a solid foam which can be electrically heated and in the form of a hollow cylinder.

DE 10 2006 026 576 A1 also describes a solid evaporator in which aerosols are generated by powder swirling by an ultrasonic-exciter.

US 7,501,152 B2 describes a transport device for transporting a starting material in powder form to a nozzle, by which the starting material in powder form can be introduced into the carrier gas stream.

DE 88 08 098 U1 describes a method of generating steam by melting a solid using an electron beam. In this case, a control circuit was provided to control the steam generation rate using a sensor. For this purpose a number of electron beams are used which heat the surface at different points.

 US 2002/0192375 A1 describes an aerosol-generator with an evaporation chamber disposed behind it. The aerosol is injected into the evaporation chamber, resulting in the aerosol evaporating there. Larger droplets can evaporate in the heated wall.

US 2010/0173067 A1 describes a CVD-reactor in which a process gas is generated by liquid evaporation in a bubbler. The mass flow is controlled by controlling the evaporation temperature.

EP 0 982 411 A2 and WO 2010/060646 A1 also describe evaporators in which the mass flow rate of the evaporated material is controlled by control of the evaporation temperature.

It is also known to generate an aerosol using a brush wheel. The brush of the brush wheel removes by the compacted powder the material carried as suspended particles in the carrier gas stream.

Also known are devices which bring liquid into the carrier gas in the form of a sprayer.

Aerosol-generators according to the prior art have the property of generating a time varying mass flow in solid or liquid suspended particles.

An object of the present invention is to propose measures that can reduce the rate of change of the steam generated by evaporation of the aerosol over time.

The problem is solved by the invention described in the claims.

Preferentially and substantially, a way is proposed to react quickly to changes in the mass flow occurring in the output gas flow by rapidly changing the temperature of the heat transfer face. The heat transfer face can be heated to a different temperature in a controlled state by a change in energy supply. Temperature control in this manner is a response to the change over time of the mass flow of steam generated in the output gas stream. By this method, not only the time-dependent variation of the mass flow in the output gas flow caused by the time-dependent variation of the mass flow of the suspended particles in the input gas flow can be compensated. The method also makes it possible to compensate for variations in evaporation rate inside the evaporator. The evaporation rate is determined not only by the thermodynamic situation inside the evaporator but also by the kinetic situation. An important parameter here is the surface temperature of the heat transfer surface. The parameters actually determine the ratio of the partial pressure of the formed vapor to the solid partial pressure. Another important parameter for the evaporation rate is the size of the free surface. The size of the free surface depends not only on the total surface area of the heat transfer face, which does not change over time, but also on the solidity ratio, which means the proportion of organic material that does not evaporate occupy the surface. The rate of fidelity is affected by variation over time. The process according to the invention is carried out under saturation conditions, which means that the partial pressure of the steam generated by the evaporator in the output gas stream is less than the saturated vapor pressure of the evaporated organic material. The average number of particles that varies over time sent into the evaporator through the input gas stream does not contribute to the time-dependent variation of the mass flow within the output gas stream. Particle size also affects. Suspended particles entering the evaporator through the inlet opening are brought into surface contact with the heat transfer face and absorb heat there. Thus, the suspended particles stay inside the evaporation chamber for a predetermined time until the suspended particles have completely evaporated. The higher the surface temperature of the heat transfer side, the shorter the residence time of the organic material not evaporated in the evaporator. The non-evaporated organic material inside the evaporator forms a kind of buffering mass. By lowering the temperature of the heat transfer side, the evaporation rate changes and the buffering mass increases. The evaporation process attempts to maintain a steady state in the long term, in which the mass flow per unit time flowing into the evaporator is equal to the mass flow per unit time discharged out of the evaporator to the outside, and thus, during temperature drops, (in the medium term) The storage mass or storage volume is enlarged, thereby increasing the size of the free surface. In the short term, the temperature drop and, together with the increase in the average residence time, result in a decrease in the mass flow exiting the evaporator out of the evaporated organic starting material. On the contrary, when the temperature of the heat transfer side is raised, such a situation leads to an increase in the evaporation rate and a shortening of the average residence time of the organic starting material not evaporated inside the evaporator. The storage mass or storage volume described above is reduced. At the same time, the free surface is reduced, resulting in a static state in which the mass flow of organic material entering the evaporator in the long run equals the mass flow exiting the evaporator. In the short term, however, temperature rises lead to an increase in the mass flow exiting the evaporator from the evaporated organic starting material. Therefore, the temperature change of the heat transfer surface causes the vapor pressure of the organic starting material in the output flow to increase when the temperature rises, and to decrease the vapor pressure when the temperature drops. With the method according to the invention, the time-dependent variation of the mass flow is compensated for by quickly changing the temperature of the heat transfer face. The average residence time is in the range of seconds. In contrast, the rate of temperature change of the heat transfer surface, which has a significant effect on the effective evaporation rate, is in the range of tenths of seconds, preferably in the range of one hundredths of seconds and particularly preferably in the range of one thousandths of seconds. have. For example, a 1 degree change in temperature on the heat transfer plane results in a 5% change in evaporation rate. According to the invention, a regulating circuit, in particular a PID-regulator, is used to change the temperature of the heat transfer face. For this purpose, a sensor is used which can detect the partial pressure of the vapor of the organic starting material in the output gas stream. As an alternative, a sensor can also be used to detect the mass flow of the vapor of the organic starting material in the output gas flow. The sensor signals of the sensor convey values provided to the adjustment circuit as adjustment values. The set value of the regulating circuit is a heating energy flow which changes the temperature of the heat transfer face. The response time of the regulating circuit is actually determined by the rate of change of temperature over time on the heat dissipation side. The rate of temperature change of the heat transfer side is at least 5 ° C / s.

Upon heating, higher rate of temperature change can be reached, which corresponds to at least 10 ° C / s. Proper molding can even reach a rate of temperature change that can change the temperature up or down by 1 degree in 4 ms. It is sufficient if the temperature of the heat transfer face is changed by ± 10 ° from the average value lying in the range of 300 ° C to 400 ° C. Preferably the heat transfer face is formed from the pores of the solid foam. In this case an open pore solid foam is used, as mentioned in the preamble and as described in the publications cited in this preface.

The device according to the invention has a sensor disposed in the output gas flow, which can detect the partial pressure of the vapor of the organic starting material or the mass flow of the starting material flowing through the steam line. The sensor signal detected by the sensor and dependent on the vapor pressure is provided to the PID controller as an adjustment value. The PID-regulator delivers a setpoint for the heating energy flow that heats the heat transfer face. The heat transfer face is preferably formed by the vessel wall, in which case the vessel forming the evaporator has a gas inlet opening and a gas outlet opening. To form a vortex in the gas flow entering the interior of the vessel for contacting the vessel walls with suspended particles which are carried by the gas flow and which may be in the solid state or the liquid state, for example, one below the flow direction of the gas inlet opening. Alternatively, a gas distributor with multiple baffles can be arranged. The heat transfer face is preferably formed by the pore wall of the open pore solid foam. Typical sizes for suspended particles are approximately 100 μm. Typical dimensions for the width of the pore opening are approximately 1 mm. The solid foam may have a pore volume of at least 95% of its total volume. Preferably the container has the form of a hollow cylinder, the walls of the hollow cylinder being formed by a cylindrical solid foam. The solid foam may be made of a ceramic material. Preferably, however, the solid foam consists of an electrically conductive material, for example graphite, or of one of the metals mentioned in the preamble, ie tungsten, rhenium, tantalum, niobium, molybdenum. Solid foams made of graphite or ceramic may be coated with the metals or with carbides of the metals. Preferably, the solid foam in the form of a hollow cylinder is joined in a thermally conductive manner with a container wall which is thin and can be heated. For example, the container case can be cooled for the purpose of heat dissipation. The electrically conductive solid foam has two electrodes through which current can flow through the solid foam. The heating power provided to the solid foam can be varied by the current variation. It is sufficient if the temperature of the solid foam is at least 50 ° higher than the temperature of the case surrounding the solid foam.

The short term rise in temperature of the heat transfer side is possible by supplying a correspondingly high current into the evaporation body formed by the solid foam. The short term drop in temperature of the evaporating body is achieved by heat release. Heat dissipation is then achieved through thermally conductive contact to the cooler case. However, evaporative heat absorbed by the suspended particles or heating of the carrier gas flowing into the vessel under cold conditions also serves to cool.

In one refinement of the invention, the manner in which the carrier gas flow flows through the aerosol-generator in the form of a pulse by connecting a suitable valve in front of it is presented. The pulse frequency is then significantly higher than the reciprocal residence time. Typical pulse rates are 10-20 hertz. Thus, the pulse length is significantly shorter than the average residence time lying in the range of approximately 1 second.

In one improved example of the present invention, it has been suggested that a temperature sensor is provided inside the evaporator, by which the average temperature of the heat transfer surface can be measured. The second sensor preferably cooperates with the regulating circuit. As the regulating circuit, a second PID regulator is preferably used, and more specifically, the adjustment value of the second PID regulator is a sensor signal of the second sensor, and the setting value of the second PID regulator is determined by the aerosol generation rate. Affect Thus, for example, the response of the second regulating circuit to the changing temperature of the heat transfer face may be a variation of the aerosol formation rate.

The first regulating circuit reacts to the fluctuations in the mass flow of the steam generated over a short period of time to vary the power provided to the heating device of the evaporator in the short term, while the second regulating circuit responds gently to the changing average temperature of the heat transfer surface. . This long term rise or fall of the average temperature of the heat transfer side is the result when the suspended particles, i.e., the less evaporated starting material is provided to or exceeded the evaporator. Thus, the second regulating circuit increases the aerosol formation rate when the average temperature of the heat transfer face increases, and decreases the aerosol formation rate when the average temperature of the heat transfer face decreases. Thereby, the first regulating circuit can only change the temperature of the heat transfer surface within the range of a predetermined temperature window. The temperature sensor measures the average temperature of the heat transfer surface. The adjustment value is a temperature signal. By mass flow as a set point, heat dissipation can be used to some extent as a set point. This situation is especially true when the temperature of the gas is significantly lower than the temperature of the heat transfer surface.

Embodiments of the present invention are described in detail below with reference to the accompanying drawings:
1 is a block circuit diagram of a first apparatus according to the present invention,
Figure 2 is a longitudinal sectional view showing the evaporator cut in accordance with the present invention,
Figure 3 shows the waveform (a) over time of the mass concentration of aerosol-particles in the input gas stream, the heating power provided (b) and the mass flow (c) in the output gas stream of the evaporated organic starting material. Is a schematic drawing, and
4 is a block circuit diagram of a second device according to the present invention.

FIG. 1 shows a coating apparatus for coating a substrate 11 made of glass with a thin luminescent organic layer to generate so-called OLEDs. Regarding the structure of the layer and the organic starting materials used, reference is made to the documents cited in the preamble and in particular US Pat. No. 7,238,389 B2, the relevant disclosures of which are incorporated herein in their entirety.

The apparatus according to the invention has a source for a carrier gas which is not shown in detail in the drawings, in which case nitrogen, hydrogen or a suitable inert gas can be used as the carrier gas. By the carrier gas line 3, carrier gas is supplied to the aerosol-generator 2, in the case of a short pulse, in some cases, the aerosol-generator having a storage vessel 2 ′, The organic starting material is stored in the storage vessel. The aerosol-generator 2 may have a brush wheel, a screw or other formed conveying means for guiding the powder stored in the storage vessel into the carrier gas flow. Instead of powder, however, liquid can also be sprayed into the carrier gas stream.

Suspended particles are formed which are sent from the gas stream through the aerosol line 4 into the evaporator 1. The evaporator 1 is described in detail in the description with respect to FIG. 2. As will be explained in further detail below, aerosol particles are provided in gaseous form in the evaporator 1. The steam associated with this is fed to the CVD-reactor through the vapor line 5 together with the carrier gas, which is heated through a heating band 6. Inside the CVD-reactor housing 7 there is a gas inlet engine in the form of a shower head powered by a steam line 5, the gas inlet engine having a gas outlet face and the gas outlet The face has a plurality of gas outlet openings arranged in a sieve form. The gas discharge face faces down vertically, forms a cover of the process chamber 10, and the bottom of the process chamber forms the surface of the susceptor 9 which faces up to the gas inlet engine 8. On the cooled susceptor 9 lies a substrate 11 to be coated, on which vapor formed in the evaporator 1 can be deposited as a layer. The reactor housing 7 is also connected to a vacuum pump 12 to set the total gas pressure in the process chamber 10 or inside the evaporator 1 in the range of 1 to 10 mbar. However, it is also possible to set the total gas pressure higher, for example in the range of 10 to 100 mbar. Through a control valve not shown in the figure, the overall pressure is kept constant.

A PID-regulator 14 is provided which interacts with the sensor 13, in which case the sensor measures the partial pressure of the vapor of the organic starting material in the steam line 5. As an alternative, however, the sensor 13 can also be formed as a mass flow meter for determining the mass flow of the vapor of the organic starting material flowing through the vapor line 5.

The sensor signal conveys a value that is proportional to the steam pressure or mass flow or depends on the characteristic curve corresponding to the steam pressure or mass flow, which forms an adjustment value of the PID-regulator 14. The set value of the PID-regulator 14 is the heating power for heating the heat transfer face 15, the temperature of the heat transfer face being the average residence of the unevaporated suspended particles of organic starting material in the evaporator 1. Affects time

The evaporator shown in detail in FIG. 2 has a connection to an aerosol line 4 with an inlet opening 18 which can take the form of an inlet nozzle. Below the flow direction of the inlet opening 18 is a gas distributor 19. This gas distributor is shown only schematically in FIG. 2. The gas distributor has in particular a plurality of baffles 19 'arranged obliquely with respect to the gas flow, in which an input gas stream containing suspended particles to be evaporated is delivered. The gas distributor 19 causes vortexing to occur inside the vessel forming the evaporator 1, which causes suspended particles to be provided to the evaporating body forming the vessel wall.

The evaporation body forms the heat transfer face 15 mentioned previously. In the present embodiment, an open pore solid foam having a pore width of approximately 1 mm is used as the evaporation body. The volume of pores corresponds to at least 95% of the total volume of the solid foam. Suspended particles enter the solid foam and accumulate in the pore walls.

The evaporation body 15 formed as described above has two electrodes 22 and 23. One electrode 22 is connected to ground. The other electrode 23 is supplied with a current used by the PID regulator 14. The current flowing through the electrically conductive solid foam 15 provides heat to the evaporation body, with the result that the heat transfer face has a temperature of 300 ° C to 400 ° C.

The evaporating body 15 in the form of a hollow cylinder is surrounded by a hollow cylindrical case 16. There is an insulating layer 17 between the case 16 and the evaporation body 15. However, the insulating layer 17 may pass heat in an electrically insulating manner. The material thickness of the solid foam 15 lies in the range of 4 to 5 mm, while the material thickness of the insulating layer 17 is approximately 0.1 mm.

The case 16 may be made of metal. However, the case may also be formed from a solid foam. The solid foam may likewise have two electrodes for heating the case 16. The temperature of the case 16 is lower than the average temperature of the evaporation body 15. Preferably, in this case, a temperature difference of approximately 50 ° C is set.

In the inlet opening 18, which lies approximately in the center of the cylinder front wall, the outlet opening 20 lying in the cylinder front wall is likewise opposite. The outlet opening 20 has a larger diameter than the inlet opening 18. Through the discharge opening 20, the output gas flow reaches the vapor line 5. The output gas stream contains vapors of evaporated organic starting materials.

Just below the flow direction of the discharge opening 20 is a cavity 21, in which the sensor 13 already mentioned is present, which is evaporated organic starting in the carrier gas. The partial pressure of mass or mass flow thereof is detected.

With such a device, the method described as follows is implemented:

The flow rate over time of the mass flow generated in the aerosol-generator 2 of suspended particles conveyed to the evaporator 1 via the aerosol line 4 is on the one hand a powder transfer due to variations caused by the structural shape. The rate of change is changed, on the other hand, the powder transfer rate is changed because of the unified particle size.

As described above, the mass flow in the suspended particles that changes with time is introduced into the evaporator, where it reaches the interior of the vessel volume through the inlet opening 18, where vortex is generated by the gas distributor 19, whereby As a result, the suspended particles penetrate into the pores of the evaporation body 15. Suspension particles are heated through contact with the surface of the heat transfer face 15 of the heat transfer body, in which case the suspended particles reach their evaporation temperature, and their own particle size and temperature of the heat transfer face 15. Depending on the evaporation at different rates. The steam thus formed exits the discharge opening 20 and flows into the steam line 5. The partial pressure of the steam, more specifically the concentration of steam in the output gas stream, is detected by the sensor 13.

The mode of supply of suspended particles in the aerosol-generator 2 is selected such that the steam generated at such mass flow rates has a partial pressure inside the carrier gas which lies below the saturated vapor pressure. The evaporator 1 operates in a stationary state for a long time, in which the average mass per unit time introduced into the evaporator 1 corresponds to the average mass per unit time discharged from the evaporator 1 by the output gas flow. do. By changing the residence time of the organic starting material not evaporated in the evaporator 1, such a balance can be changed for a short period of time. Increasing the temperature of the heat transfer side increases the mass flow of the organic starting material exiting the evaporator for a short time, and decreasing the mass flow of the organic starting material exiting the evaporator for a short time. Thereby, variation compensation of the output mass flow is achieved by the PID-regulator 14.

The variation in mass flow observed in the steam line 5 without mass flow compensation has a variation time greater than 1 second. 3 shows a typical waveform of mass flow of powder formation rate over time. Thus, the curve a represents the feed rate at which the organic starting material to be actually evaporated is supplied to the evaporator 1. The horizontal time axis then lies at a value corresponding to the mass flow averaged over time.

The sensor 13 can detect a deviation of the partial pressure in the output gas flow that deviates from the mean value over time. When the deviation is upwards, the PID-regulator reduces the heating power to heat the heat transfer face 15. Since the temperature of the heat transfer side can be changed by at least 100 ° C./s and this temperature variation already changes the evaporation rate by 5%, a very rapid temperature drop up to 10 ° C. at the surface of the evaporation body 15 The residence time of the material not evaporated is increased instantaneously. This situation causes the output mass flow (curve c in FIG. 3) to rise much less than the input mass flow, for example. As soon as the PID-regulator confirms through the sensor 13 that the 'output mass flow (curve c) no longer changes', the regulator starts to raise the heating power (curve b) again.

When the sensor 13 detects a deviation downward from the average mass flow, the PID-regulator 14 is controlled in reverse by the increase of the heating power. Even in this case, the temperature may vary by up to 10 ° C. The average residence time of the non-evaporated material in the evaporator 1, which is reduced by the temperature rise, raises the mass flow in the output gas flow for a short time. Thus, the non-evaporated material that clings to the heat transfer face 15 during the average residence time will form a buffering mass that can be altered by a change in evaporation temperature.

4 schematically shows a further device for depositing a layer of organic starting material, which is actually different from the device according to FIG. 1 in that a second sensor 24 is provided. By the sensor 24 the average temperature of the heat transfer surface 15 can be measured. The temperature sensor 24 delivers an adjustment value for the PID-regulator 25 that varies the rate of aerosol generation in response to a long term temperature change of the heat transfer face 15. In the embodiment shown in FIG. 4, there is further shown a mass flow regulator 26 that can adjust the mass flow of the carrier gas to a predetermined value.

The sensor 13 changes the mass flow during the short time period, in more detail, to raise or lower the temperature of the heat transfer face 15 within a time interval that falls within the second- or subsecond range. While this is detected, the temperature sensor 24 detects temperature fluctuations of the heat transfer surface 15 which are averaged over time. In this case, “temperature averaged over time” is understood as temperature averaged over several seconds. For example, the time interval over which the average temperature is calculated can be up to ten times the time interval at which the first regulating circuit 14 responds to the partial pressure change of the vapor in the carrier gas. Thus, the regulating circuit 25 will react to long term changes in the temperature of the heat transfer face 15. The causes of such changes are too low aerosol incidence or too high aerosol incidence. Correspondingly, the regulator 25 reacts to a long term average temperature rise of the heat transfer face 15 by an increase in the rate of aerosol generation by the aerosol-generator 2. The regulator 25 responds to the average temperature drop of the heat transfer face 15 by decreasing the rate of aerosol generation in the aerosol-generator 2.

With such measures the temperature of the heating power controlled evaporator 1, more specifically the temperature of the heat transfer face 15, can only be varied within a predetermined temperature range. Thus, the buffering mass in the organic starting material inside the evaporator 1 is actually kept constant in view of the temporal average.

Since the two regulating circuits 14, 25 having very different time constants from each other operate, the mutual influence is minimal.

It is also possible to operate the device according to FIG. 4 without the PID-regulator 14 or the sensor 13.

All features disclosed are important to the invention (as such). Accordingly, even for the purpose of listing together the features of the associated / attached priority document (a copy of the prior application) in the claims of this application, the disclosure of this application also includes the disclosure of the priority document in its entirety. The dependent claims feature in the text optionally arbitrarily arranged, in particular for carrying out the splitting application on the basis of the above claims, a unique and inventive improvement of the prior art.

1: evaporator 2: aerosol-generator
2 ': storage vessel 3: carrying gas line
4: aerosol line 5: steam line
6: heating band 7: CVD-reactor housing
8: gas inlet (shower head) 9: susceptor
10: process chamber 11: substrate
12: vacuum pump 13: sensor
14: PID regulator 15: heat transfer surface
16: case 17: insulation layer
18 inlet opening / nozzle 19 gas distributor
19 ': baffle 20: discharge opening
21: cavity 22, 23: electrode
24: temperature sensor 25: PID controller
26: mass flow regulator
a: mass flow of aerosol particles
b: heating energy
c: mass flow of steam

Claims (15)

A method for depositing a layer of organic starting material on a substrate (11),
The organic starting material is an aerosol in the form of suspended particles that is sent into the evaporator 1 in a carrier gas stream, which suspended particles contact the heat transfer face 15 heated by a temperature control device inside the evaporator 1. Vaporizes after a residence time, which also depends on the temperature of the heat transfer face 15, and the vapor of the carrier gas generated as described above exits the evaporator 1 as the output gas flow and is sent into the process chamber 10. In the deposition method, the vapor in the process chamber 10 is condensed while forming a layer on the surface of the substrate 11,
The temperature of the heat transfer surface 15 is measured by a temperature sensor 24 and the sensor signal as a setting value by the adjustment circuit 25 in which the sensor signal of the temperature sensor 24 is provided as an adjustment value. The mass flow of the organic starting material flowing into the evaporator 1 as a function of
The organic starting material forms a non-evaporated buffering mass at the heat transfer face 15, and the evaporation rate of the buffering mass depends on the average residence time of the organic evaporated material that is not evaporated, wherein the average residence time is Temperature dependent, and the temperature is varied using a regulator 14 to compensate for variations in output mass flow,
Way. The method of claim 1,
Characterized in that the heat transfer face 15 is formed by pores of an open pore solid foam defined by a web forming a wall of an open cell,
Way. The method of claim 2,
Said pore-shaped solid foam forms a vessel which forms the wall of the evaporator 1,
Way. The method of claim 2,
The solid foam 15 or the coating of the solid foam is electrically conductive, characterized in that it is resistively heated by the current flow through the solid foam 15 or coating,
Way. An apparatus for evaporating organic suspended particles transported in a carrier gas stream,
The apparatus is formed in the form of a container 1 having an inlet opening 18 for input gas flow, an outlet opening 20 for output gas flow and a heat transfer face 15 therein, the heat transfer face 15 exits from the container 1 through the discharge opening 20 when the suspended particles sent into the container 1 through the inlet opening are brought into contact with the heat transfer face 15 by a fluctuating heating energy flow. An evaporation apparatus, which can be heated to a dynamically controllable temperature evaporated with an organic vapor discharged to the outside,
A temperature sensor 24 for measuring the temperature of the heat transfer surface 15 and an adjustment circuit 25 in which a sensor signal of the temperature sensor 24 is provided as an adjustment value, and the adjustment circuit is a set value. Change the mass flow of the organic starting material flowing into the evaporator 1 as a function of the sensor signal,
The regulating circuit 25 is a regulator that changes the temperature of the heat transfer face 15 to compensate for variations in output mass flow by changing the buffering mass of organic vaporized particles that have not evaporated on the heat transfer face 15. It characterized by including (14),
Device. The method of claim 5,
Said heat transfer face 15 is formed by a solid foam,
Device. The method of claim 5,
The heat transfer face 15 is characterized in that it is formed by an open pore solid foam forming the vessel wall.
Device. The method of claim 6,
The solid foam is electrically conductive and interacts with two electrodes 22, 23, by which a heating current can pass through the solid foam to generate heat inside the solid foam doing,
Device. The method of claim 6,
By combining the solid foam with the relatively cooler ambient 16, the temperature of the solid foam can be varied by ± 10 ° C. with a temperature change rate of at least 5 ° C./s relative to the average temperature.
Device. delete delete delete delete delete delete

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