Coating material evaporation device and use thereof

Abstract

The invention relates to a coating material evaporation device (100) which comprises a first material storage part (10), a first pressure and temperature sealing metering device (11), a first conveying section (12), a second material storage part (13), a second pressure and temperature sealing metering device (14), a second conveying section (15) and a porous evaporation component (16) which are connected in sequence. The evaporation device (100) further comprises a heater (17) for heating the porous evaporation member, a pressure measurement device (21), a sublimation chamber (19) and a cover plate (20). The porous evaporation member (16), the heater and the pressure measuring device (21) are arranged in the sublimation chamber (19), and the cover plate (20) is on the lower side of the sublimation chamber (19) to close the sublimation chamber. The second pressure and temperature sealed metering device (14) is configured to be controlled as a function of the pressure inside the sublimation chamber (19) measured by the pressure measuring device (21).

Description

Technical Field

[0001] The present invention relates to an apparatus for evaporating coating materials, in particular for use in the production of solar cells, and to its use. Background Art

[0002] In the manufacture of optoelectronic devices such as thin-film solar cell devices, light-emitting devices, displays, etc., coating materials are typically evaporated and deposited under vacuum conditions. "Vacuum" refers to any pressure below atmospheric pressure. However, evaporation and deposition can also be carried out at atmospheric pressure or above atmospheric pressure. Deposition systems including evaporation apparatuses are referred to as batch deposition systems and continuous deposition systems. Generally, these systems include at least one deposition chamber, means for accommodating and / or transporting substrates, means for heating and / or cooling the deposition chamber and / or the substrates, at least one coating evaporation apparatus (also referred to as an evaporation source) suitable for evaporating or sublimating the coating material, means for heating at least one evaporation source, and means for pumping and / or ventilation. The term "evaporation" is generally used as a general term to refer to all thermally activated phase changes that occur on the surface of a substance from a solid or liquid state to a gaseous state. That is, evaporation generally means vaporization or sublimation. Vaporization is the phase change of a substance from a liquid phase to a vapor, and sublimation is the phase change of a substance directly from a solid state to a gaseous state without passing through a liquid phase. Sublimation is typically carried out in a closed space sublimation (CSS) system, which is sometimes also referred to as a closed space sublimation system. Evaporation systems can be divided into bottom-up systems and top-down systems.

[0003] Bottom-up deposition systems typically include evaporation sources arranged below the substrate to be coated. For example, the system disclosed in WO 2010 / 035130A2. The evaporation source evaporates the coating material at its upper end upward onto the lower side of the substrate to be coated. In bottom-up systems, the fixation and corresponding conveyance of the substrate are difficult and may cause damage to the substrate or the deposited material layer.

[0004] Top-down deposition systems typically include evaporation sources arranged above the substrate to be coated. For example, the systems disclosed in KR 1020150017849A and US2013 / 0115372 A1. The evaporation source evaporates the coating material at its upper end, and the evaporated coating material is redirected downward and deposited onto the upper side of the substrate to be coated.

[0005] However, especially for closed space sublimation, it is necessary to continuously supply the evaporation source with coating material, because the characteristics of the coating film (such as the thickness and composition of the coated film and the optical or electrical properties of the coating film) should not vary with the usage time of the evaporation source, but this depends on the filling level of the evaporation source. Summary of the Invention

[0006] The object of the present invention is to provide an apparatus for evaporating coating materials that can continuously supply or coat materials and its use.

[0007] The above objects are achieved by a top-down evaporation source and its use as described in the independent claims. Specific embodiments are the subject matter of the dependent claims.

[0008] The device according to the invention for evaporating coating materials, in particular for the production of solar cells, comprises at least the following components:

[0009] a) a first material storage portion, the first material storage portion being used to store granular coating material under conditions of temperature T1 and pressure p1;

[0010] b) a first pressure and temperature sealing metering device;

[0011] c) a first conveying section;

[0012] d) a second material storage portion, the second material storage portion being configured to receive a granular coating material under conditions of temperature T2 and pressure p2;

[0013] e) a second pressure and temperature sealing metering device;

[0014] f) a second conveying section, wherein the pressure in the second conveying section is p3;

[0015] g) a porous evaporation member and a heater, the porous evaporation member being configured to receive the particulate coating material at a temperature T3, the heater being configured to heat the porous evaporation member to a temperature T4;

[0016] h) a sublimation chamber, wherein the pressure inside the sublimation chamber is p4, and the porous evaporation member and the heater are arranged in the sublimation chamber; and

[0017] i) A cover plate, which is on the lower side of the sublimation chamber and is provided with gas outlet openings.

[0018] The components are connected in the order listed above. The first material storage section is configured to store granular coating material at a temperature T1 and a pressure p1, and may be equipped with suitable devices, such as a heater or a cooling device or a pump, to maintain the conditions of T1 and p1. The first material storage section is arranged and configured to supply a controllable amount of coating material particles to the second material storage section through a first pressure and temperature sealing metering device through the first conveying section. Or in other words: the first pressure and temperature sealing metering device is configured to supply a controllable amount of coating material particles to the second material storage section through the first conveying section, while temperature and pressure sealing and isolating the first material storage section from the first conveying section. The pressure p2 in the first conveying section and the second material storage section is configured to be settable. The temperature T2 in the second material storage section is configured to be settable, and the temperature within the first conveying section can be changed from T1 to T2. In order to set the temperature and pressure, the first conveying section and the second material storage section may include suitable devices as described above with respect to the first material storage section. The second material storage section is arranged to discharge a controllable amount of particles into the porous evaporation member via the second conveying section by a second pressure and temperature sealing metering device. In other words: the second pressure and temperature sealing metering device is configured to supply a controllable amount of coating material particles into the porous evaporation member via the second conveying section, while isolating the second material storage section and the second conveying section by temperature and pressure sealing. In the second conveying section, the pressure p3 is configured to be settable, and the temperature is set to allow the coating material to enter the porous evaporation member at a temperature T3, wherein the temperature within the second conveying section can vary from T2 to T3. Similarly, the second conveying section can include corresponding suitable devices for achieving temperature and pressure.

[0019] The heater is arranged and configured to heat the temperature in the porous evaporation member to a temperature T4 capable of evaporating the particulate coating material. The heater can be, for example, a heating lamp, an RF coil or a resistive heater (e.g. made of a suitable high temperature resistant metal alloy), or a fluid temperature control system, wherein the heater is placed at a certain distance from the porous evaporation member, as described below.

[0020] The porous evaporation member is arranged and configured to release the evaporated coating material into the sublimation chamber through the holes of the porous evaporation member. In other words: the evaporated coating material can enter the sublimation chamber via the holes of the porous evaporation member, while solid particles cannot penetrate the porous evaporation member. That is, the porous evaporation member improves the uniformity of the steam entering the sublimation chamber and can be used as a filter that only allows gaseous particles to penetrate. To this end, the porous evaporation member is at least partially made of a porous material (e.g., porous ceramic). The heater is arranged at a distance from at least the region made of the porous material in the porous evaporation member so that the evaporated coating material can escape from the porous evaporation member. The porous evaporation member can be formed as a hollow body with one long extension and one or two shorter extensions, such as a hollow cylinder or a hollow cuboid or a tube, wherein the body can be closed at one or both ends relative to its long extension, i.e., not a porous material. The outer diameter of the porous evaporation member is in the range of 1 mm to 100 mm, preferably in the range of 10 mm to 100 mm, and the wall thickness of the porous evaporation member is 1 mm to 50 mm, preferably 1 mm to 10 mm. The porous material may have a porosity of 35%, and a pore size range of 0.1 μm to 50 μm, preferably in the range of 1 μm to 20 μm. The porous evaporation member is provided with at least one opening connected to the second conveying section, and the granular coating material enters the porous evaporation member through the opening. The porous evaporation member may include an accumulation area, and the introduced granular coating material accumulates in the accumulation area and is heated to evaporate. The accumulation area may be made of a non-porous material (e.g., a non-porous ceramic).

[0021] In order to prevent the evaporated coating material from recondensing, the average temperature of the entire sublimation chamber, i.e. all components arranged therein and all walls (including the cover plate), is kept at least close to T4, i.e. T4±10%. The heating element can of course have a locally higher temperature to transfer sufficient heat to other components. To this end, each component can include suitable means for controlling the temperature.

[0022] The cover plate is arranged and configured to enable the evaporated coating material to leave the sublimation chamber through the opening of the cover plate and be deposited on the surface of the substrate, which is fixed or moved below the sublimation chamber. As the coating material evaporates and escapes the sublimation chamber, the pressure inside the porous evaporation member may be higher than the pressure p4 inside the sublimation chamber, especially the pressure near the cover plate. The pressure inside the porous evaporation member may be equal to p3. The lower side of the sublimation chamber refers to the bottom or side of the sublimation chamber facing gravity.

[0023] The coating material evaporation device further comprises a pressure measuring device arranged in the sublimation chamber for detecting the pressure p4 in the sublimation chamber. At least the second pressure and temperature sealing metering device is configured to be controllable depending on the pressure p4 in the sublimation chamber.

[0024] Advantageously, such a coating material evaporation device can continuously and controlled supply the coating material, and the evaporated coating material can maintain a uniform vapor pressure over time. In addition, no carrier gas is required to transport the evaporated coating material to the substrate to be coated below the sublimation chamber.

[0025] The coating material of the present invention is any material suitable for coating onto a substrate and evaporating under a certain pressure and a certain temperature.

[0026] The evaporation device of the invention is suitable for static or continuous deposition processes, preferably for continuous deposition processes, and can be used in combination with a suitable deposition system, in particular in combination with a vacuum deposition system as described above. Furthermore, the evaporation device of the invention is particularly suitable for deposition processes in solar cell production processes, in particular sublimation processes such as CSS. The evaporation device of the invention is suitable for permanent deposition systems, since the coating material can be replenished without interrupting the deposition process, and the crucible containing the coating material does not need to be replaced after a predetermined evaporation period, as in batch systems.

[0027] The first material storage section and the second material storage section both refer to spaces that can accommodate granular coating materials, and can store the contained coating materials at a predetermined temperature and a predetermined pressure. In some embodiments, both storage sections are surrounded by side walls, and the side walls of the first material storage section also surround the first pressure and temperature sealing metering device, and the side walls of the second material storage section surround the second pressure and temperature sealing metering device. The second material storage section, the first conveying section, the first pressure and temperature sealing metering device, and the second pressure and temperature sealing metering device together form a closed space.

[0028] In some embodiments, the first material storage section or the second material storage section can be omitted by reasonably expanding the other storage section (referring to the second material storage section or the first material storage section) and selecting the most suitable first pressure and temperature sealing metering device or the second pressure and temperature sealing metering device without affecting the described functions.

[0029] The shapes of the material storage part and the conveying section are not limited as long as these parts can meet their corresponding functions. That is, the shapes of the material storage part and the conveying section can be, for example, a cylinder that is circular or elliptical at the upper end and / or at the lower end, or a prism (such as a cuboid), or a truncated cone or a truncated pyramid or any other type of object.

[0030] The first conveying section and the second conveying section are freely oriented in space, i.e., vertically or horizontally, as long as it is ensured that the coating material can be conveyed by the first conveying section and the second conveying section. In some embodiments, the first conveying section and / or the second conveying section can be arranged in the vertical direction so that the coating material falls or drops through the first conveying section and / or the second conveying section. In other embodiments, the first conveying section and / or the second conveying section can be arranged at an angle greater than 0 ° (zero degree) relative to the horizontal line so that the coating material slides through the first conveying section and / or the second conveying section. In other embodiments, a special conveying device (such as a conveyor or other conveying device) can be arranged in the first conveying section and / or the second conveying section to assist the first conveying section and / or the second conveying section in conveying the coating material. The first conveying section and the second conveying section can be arranged and equipped with a conveying device in the same or different manners.

[0031] The first material storage, the second material storage, the first delivery section, the second delivery section, the first pressure and temperature sealed metering device, the second pressure and temperature sealed metering device, and the sublimation chamber can be made of any material that can ensure the function of the corresponding components. In some embodiments, these components are made of materials that are inert to the coating material in the solid, liquid or gas phase. For example, these components can be made of stainless steel, graphite, ceramic material, or any other suitable material. In addition, the materials of different components may be different from each other.

[0032] The predetermined temperature in the first material storage, the second material storage, the first conveying section, the second conveying section, the porous evaporation member and the sublimation chamber can be achieved by known heating or cooling devices, such as heating lamps, RF coils or resistance heaters or fluid temperature control systems, wherein these heating or cooling devices can be placed outside the corresponding components or at a certain distance from the corresponding components, or can even be incorporated into the corresponding components (for example, incorporated into the side wall), or can be arranged inside the corresponding components (for example, arranged inside the first material storage or inside the sublimation chamber). Such heating or cooling devices can be physically separated from the corresponding components, and the heat energy is transferred over a long distance by radiation or air convection.

[0033] According to the present invention, the bottom of the sublimation chamber is formed by a cover plate. The cover plate in the present invention refers to a polygonal or arc-shaped plate-like element, which is suitable for forming the bottom of the sublimation chamber and transmitting the evaporated coating material downward. In some embodiments, the cover plate is a quadrilateral element, preferably a rectangle, and its thickness is in the range of 0.1 mm to 20 mm.

[0034] The cover plate is in direct physical contact with the evaporated coating material. In some embodiments, the cover plate is configured to be heatable so as to prevent the vaporized coating material from re-sublimating, i.e., depositing, at the cover plate. The cover plate can be heated by known heating means, such as by heating lamps, RF coils, or resistive heaters, wherein these heating means can be placed outside the cover plate or at a distance from the cover plate, or can even be incorporated into the cover plate. Furthermore, the cover plate itself can be a heater, i.e., the cover plate includes a material that generates heat when an electric current flows through it.

[0035] In some embodiments, the cover plate is made of graphite, ceramic, or a polycrystalline material such as silicon carbide, preferably graphite.

[0036] In order to transfer the evaporated coating material to the substrate to be coated, the cover plate includes a plurality of gas discharge openings or holes. Each hole (i.e., opening) has an upper end (i.e., inlet) arranged on the upper surface of the cover plate and a lower end (i.e., outlet) arranged on the lower surface of the cover plate. The upper surface of the cover plate faces the interior of the sublimation chamber, and the lower surface of the cover plate faces the substrate. These openings can have any cross-sectional shape at the upper surface and the lower surface and between the upper surface and the lower surface, wherein the cross-sectional shapes of these openings at the upper surface and the lower surface can even be different from each other. In some embodiments, each of the plurality of holes can have any cross-sectional shape, such as an arc or a quadrilateral, wherein the cross-sectional shapes of some or all of the holes can be the same or can be different from other holes.

[0037] The plurality of holes defines a deposition rate on the substrate. In some embodiments, the cross-sectional area of ​​each single hole in the plurality of holes is within 0.5 mm 2 Up to 10mm 2 In some embodiments, more holes with a larger total cross-sectional area are provided at the circumferential edge of the cover plate to compensate for the lower deposition rate at the edge of the cover plate relative to the central area.

[0038] In an embodiment, the temperature: T1<T2<T3<T4. That is, a temperature gradient is formed along the extension direction of the evaporation device, with the highest temperature in the porous evaporation member and the sublimation chamber. In some embodiments, T1 is about 25°C or room temperature, T2 is about 300°C, T3 is about 400°C, and T4 is in the range of 700°C to 1000°C, depending on the type of coating material and its material-specific sublimation or evaporation temperature. The temperature gradient includes the lowest temperature at the upper end of the evaporation device (i.e., in the first material storage section). Advantageously, this can continuously replenish the solid granular coating material to the first material storage section at the cooler upper end of the evaporation device, thereby ensuring that the deposition process is uninterrupted. In addition, during the process of supplying the coating material from the first material storage section to the porous evaporation member for evaporation, it can be continuously heated.

[0039] In some embodiments, the temperature gradient between T1 and T4 includes a temperature range of 675K to 975K.

[0040] In some embodiments, the pressures p1 to p3 may be the same, for example, 1000 Pa, wherein the pressure within the porous evaporation member may be equal to p3. In other embodiments, at least one of the pressures p1 to p3 may be different from the other pressures. For example, p1 and p2 may be in the range of 100 Pa to 1000 Pa, and p3 may be 1000 Pa. As described above, p4 near the cover plate in the sublimation chamber may be lower than p3, for example, 5 Pa.

[0041] In some embodiments, the first material storage portion has a closable filling opening for filling with the granular coating material.

[0042] Advantageously, the pressure p1 can be adjusted as described above, for example below normal pressure.

[0043] In some embodiments, the first pressure and temperature sealing metering device is a rotary feeder as is known in the art.

[0044] The first pressure and temperature sealed metering device is configured to feed a small amount of granular coating material from the first material storage to the subsequent sections, i.e. the first conveying section and the subsequent components in a substantially quantitative manner. On the other hand, the first pressure and temperature sealed metering device is still sufficient to stop the material supply and thus the deposition process in a reasonably short time.

[0045] In some embodiments, the second pressure and temperature sealing metering device is a rotary feeder, a valve, a pinch valve, an adjustable flow orifice, or an adjustable flow path constriction device.

[0046] Advantageously, the second pressure and temperature sealed metering device acts as a fine feeder, which only supplies a small amount of particulate coating material via the second conveying section into the porous evaporation member. As a result, the coating material entering the porous evaporation member can be very quickly, almost immediately. Therefore, the coating material first filled into the evaporation device can be evaporated first (first in, first out). In addition, the second pressure and temperature sealed metering device can very quickly and easily adjust the amount of coating material supplied so that the desired pressure p4 is reached in the sublimation chamber. For example, the holes or apertures of the second pressure and temperature sealed metering device can be adjusted.

[0047] In some embodiments, the measured values ​​of the pressure measuring device are transmitted to a data processing device, which can control the second pressure and temperature sealing metering device, and optionally the first pressure and temperature sealing metering device. That is, the evaporation device also includes a data processing device, which is used to receive the measured values ​​of the pressure measuring device and control the second pressure and temperature sealing metering device, and optionally the first pressure and temperature sealing metering device.

[0048] The data processing device thus serves as a control device, controlling the operation of the second metering device at least in accordance with the output signal of the pressure measuring device. In addition, further components of the coating material evaporation device (e.g. the first metering device, one or more heaters or a pump) can be controlled by the same data processing device or another data processing device in accordance with the output signal of the pressure measuring device.

[0049] In some embodiments, the data processing device further controls the device, in particular the heater, and therefore further sensors are arranged in the device, in particular temperature sensors are arranged in the sublimation chamber and / or the porous evaporation member.

[0050] That is, the evaporation device further comprises at least one further sensor, for example a temperature sensor arranged in the sublimation chamber or the porous evaporation member, and the data processing device can also control at least a heater for heating the porous evaporation member according to an output result of the at least one further sensor.

[0051] In some embodiments, the heater is disposed on one or more sides of the porous evaporation member substantially parallel to the longitudinal axis of the porous evaporation member. The longitudinal axis is an axis parallel to the longer extension of the porous evaporation member.

[0052] Advantageously, the porous evaporation member can be efficiently heated.

[0053] In some embodiments, the longitudinal axis of the porous evaporation member is vertically oriented, with its upper end open and connected to a second conveying section for introducing the particulate coating material; the lower end of the porous evaporation member is closed. That is, the porous evaporation member is formed to resemble a deep can with a small diameter. The upper end of the porous evaporation member is formed as an opening connected to the second conveying section, through which the particulate coating material can be introduced into the porous evaporation member. The bottom or lower end of the porous evaporation member is formed as a closed wall. In these embodiments, at least the side walls of the porous evaporation member extending vertically are made of a porous material.

[0054] In embodiments where the porous evaporation member is vertically oriented, deflector plates are alternately arranged on the inner wall of the porous evaporation member. The alternating deflector plates repeatedly reflect the incident particles of the particulate coating material, thereby extending the flight distance of the incident particles in the porous evaporation member and / or slowing down the speed of the incident particles during their movement towards the lower end of the porous evaporation member. That is, the alternating deflector plates extend from the inner wall of the porous evaporation member into the interior of the porous evaporation member and extend downward at an angle of less than 90° with respect to the inner wall of the porous evaporation member below. The angle is preferably in the range of >0° to ≤90°, preferably in the range of 15° to 70°. The deflector plates preferably extend along the longitudinal axis of the porous evaporation member beyond the middle of the short extension of the porous evaporation member but do not extend to the other inner wall of the opposite porous evaporation member. The arrangement of the deflector plates prevents the particulate coating material from being directly conveyed from the upper end to the lower end of the evaporation member.

[0055] The deflector plates can repeatedly reflect the incident particles of the particulate coating material. As a result, the flight distance (i.e., the flight path in the porous evaporation member) of the incident particles of the particulate coating material is extended, so that the incident coating material is further pulverized into smaller particles and can be heated more evenly, and can even be evaporated in the upper region of the porous evaporation member rather than only at the lower end of the porous evaporation member. Therefore, the evaporated coating material can escape from most of the longitudinal extension of the porous evaporation member.

[0056] In some embodiments, the longitudinal axis of the porous evaporation member is horizontally arranged, and there is an inlet opening between the ends of the porous evaporation member. The inlet opening is connected to a second conveying section for introducing the particulate coating material, where the porous evaporation member is closed at both ends.

[0057] Both ends of the porous evaporation member are on the same horizontal line. The entire extension of the porous evaporation member is made of a porous material. In some embodiments, the porous evaporation member is not made of a porous material only at the position opposite to the inlet opening. During the operation of the evaporation device, the particulate coating material is introduced into the porous evaporation member through the inlet opening.

[0058] In some embodiments, a plurality of components a) to g) are associated with a common sublimation chamber. That is, for example, a plurality of porous evaporation members are arranged in a sublimation chamber, wherein each individual porous evaporation member is connected in a sequence, wherein the sequence includes a first material storage portion, a first pressure and temperature sealing metering device, a first delivery section, a second material storage portion, a second pressure and temperature sealing metering device, and a second delivery section, and a separate heater for the heating element is arranged and associated with each individual porous evaporation member. A plurality of components a) to g) refers to at least one of each of components a) to g), which components can be selected independently.

[0059] This arrangement can evaporate the same coating material simultaneously through multiple porous evaporation members, thereby increasing the amount of coating material evaporated in the sublimation chamber. Therefore, the deposition rate of the coating material can be increased. In other embodiments, this arrangement can evaporate different coating materials simultaneously through multiple porous evaporation members, thereby providing a mixed or composite evaporated coating material or doped evaporated coating material in the sublimation chamber, wherein the composition or doping content of the evaporated (and subsequently deposited) coating material can be accurately adjusted. In particular, coating materials with different evaporation temperatures (also meaning having different sublimation temperatures) can be evaporated simultaneously.

[0060] In a further embodiment, a plurality of components a) to g) are associated with a common sublimation chamber, which also means that a plurality of porous evaporation members are arranged in one sublimation chamber, wherein each individual porous evaporation member is connected in at least two individual sequences, each of which comprises a first material storage, a first pressure and temperature sealed metering device, a first delivery section, a second material storage, a second pressure and temperature sealed metering device and a second delivery section, and a separate heater for the heating element is arranged and associated with each individual porous evaporation member. This can allow, for example, different coating materials or coating materials and doping materials to be mixed in the porous evaporation member.

[0061] In some embodiments, a plurality of components a) to g) are associated with a common sublimation chamber, which also means that a plurality of porous evaporation members are arranged in one sublimation chamber, wherein each individual porous evaporation member is connected to a second delivery section. The second delivery section is connected to at least two individual sequences, the at least two individual sequences comprising a first material storage, a first pressure and temperature sealed metering device, a first delivery section, a second material storage, a second pressure and temperature sealed metering section, and a separate heater for the heating element is arranged and associated with each individual porous evaporation member. This allows different coating materials or coating materials and doping materials to be mixed in the second delivery section.

[0062] In some embodiments, the first material storage portions of different porous evaporation members may store the same coating material or different coating materials.

[0063] In some embodiments, multiple components b) to g) are connected to the same first material storage section, and the porous evaporation components are arranged in one sublimation chamber or in different sublimation chambers. That is, multiple porous evaporation components are arranged in one sublimation chamber, wherein each individual porous evaporation component is connected in a separate sequence, wherein the individual sequence includes a first pressure and temperature sealing metering device, a first conveying section, a second material storage section, a second pressure and temperature sealing metering device, and a second conveying section, and wherein a separate heater for heating a separate porous evaporation component is arranged and associated with each separate porous evaporation component. However, compared with the above embodiment, all of these separate porous evaporation components and their separate component sequences are connected to the same first material storage section. Or in other words, multiple first pressure and temperature sealing metering devices are connected to one first material storage section.

[0064] This arrangement can simultaneously evaporate the same coating material through a plurality of porous evaporation members, thereby increasing the amount of evaporated coating material in the sublimation chamber. Therefore, the deposition rate of the coating material can be increased.

[0065] The invention also relates to the use of an evaporation device to coat the surface of a substrate with a coating material by moving or placing the substrate below the gas outlet opening of the cover plate. That is, the evaporation device of the invention is used as a top-down evaporation device during the deposition of the coating material on the surface of the substrate below the evaporation device.

[0066] In some embodiments, the substrate is a substrate for a thin film solar cell. Here, "substrate" refers to any kind of semi-finished thin film solar cell, that is, a thin film solar cell at any stage of production, as long as a layer needs to be deposited on the surface of the semi-finished solar cell by evaporation. In particular, the substrate can be a substrate such as a transparent substrate (such as glass) or an opaque substrate, wherein the substrate may not include any additional layers or may include at least one of an electrode layer (such as a transparent electrode layer or an opaque electrode layer) or any buffer layer or any absorption layer.

[0067] The present invention also relates to a method for evaporating a coating material using the evaporation device of the present invention. The method comprises:

[0068] Filling and storing the granular coating material in a first material storage portion at a temperature of T1 and a pressure of p1;

[0069] conveying a first quantity of coating material particles from a first material reservoir via a first conveying section into a second material reservoir by means of a first pressure- and temperature-tight metering device;

[0070] storing the received quantity of particles in a second material storage portion at a temperature T2 and a pressure p2;

[0071] conveying a second quantity of coating material particles from a second material reservoir through a second conveying section into the porous evaporation member by means of a second pressure and temperature tight metering device;

[0072] controlling the temperature in the second conveying section so that the temperature of the particles of the coating material when entering the porous evaporation member is T3, and controlling the pressure in the second conveying section to p3;

[0073] heating the porous evaporation member to a temperature T4, thereby evaporating the coating material, wherein the evaporated coating material escapes from the pores of the porous evaporation member made of the porous material and enters the sublimation chamber;

[0074] discharging evaporated coating material from the sublimation chamber through the openings in the cover plate; and

[0075] The pressure p4 in the sublimation chamber is detected by a pressure measuring device arranged in the sublimation chamber, and the second pressure and temperature sealing metering device is controlled according to the detected pressure p4.

[0076] Thus, the granular coating material to be evaporated is delivered to the porous evaporation member via two material storages, two metering devices and two conveying sections, wherein the coating material is preheated during the process of entering the porous evaporation member from the first material storage. Since the first metering device and the second metering device are pressure and temperature sealed metering devices, the temperature and pressure of the different sections in the process can be adjusted individually, i.e., the temperature and pressure in the first material storage, in the first conveying section, in the second material storage and in the second conveying section. In addition, the pressure p4 in the sublimation chamber (which depends on the amount of evaporated coating material present in the sublimation chamber) can be adjusted by controlling the second pressure and temperature sealed metering device, i.e., controlling the second number of coating material particles discharged from the second material storage via the second conveying section to the porous evaporation member by the second pressure and temperature sealed metering device, thereby controlling the amount of evaporated coating material escaping the sublimation chamber through the opening of the cover plate, thereby accurately controlling the deposition rate of the coating material on the substrate.

[0077] In order to realize the present invention, it is advantageous to combine the above-mentioned embodiments with the features of the claims. However, the embodiments of the present invention described in the foregoing specification are examples given by way of illustration, and the present invention is not limited thereto. Any modifications, changes and equivalent arrangements should be deemed to be included within the scope of the present invention.

[0078] Although specific embodiments have been illustrated and described herein, those of ordinary skill in the art will appreciate that various alternative and / or equivalent embodiments may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Accordingly, the present invention is intended to be limited only by the claims and their equivalents. Description of the Drawings

[0079] The drawings are provided to further understand the embodiments of the present invention and are incorporated into and constitute a part of this specification. The drawings illustrate embodiments of the present invention and, together with the description, are used to explain the principles. By referring to the following detailed description, other embodiments of the present invention and many of the intended advantages will be better understood. The elements in the drawings are not necessarily drawn to scale. Like reference numerals represent corresponding like parts.

[0080] Figure 1 A schematic diagram showing a first embodiment of the evaporation device in the present invention;

[0081] Figure 2A A schematic diagram showing a second embodiment of the evaporation device in the present invention;

[0082] Figure 2B Shows Figure 2A A cross-sectional view of the sublimation chamber 19 along line A-A in

[0083] Figure 3A An exemplary embodiment of the sublimation chamber is shown in a cross-section along the first direction;

[0084] Figure 3B Shows Figure 3A A cross-sectional view of the sublimation chamber in along line B-B;

[0085] Figure 4 A shows a schematic diagram of a third embodiment of the evaporation device in the present invention; and

[0086] Figure 4B A view showing an embodiment of a porous evaporation member and a heater in a third embodiment of the arrangement in the sublimation chamber.

[0087] Reference Numerals

[0088] 100, 101, 102 Evaporation device

[0089] 10, 10a - 10c First material storage part

[0090] 11 First pressure and temperature sealing metering device

[0091] 12 First conveying section

[0092] 13 Second material storage department

[0093] 14, 14a-14c Second pressure and temperature sealing metering device

[0094] 15 Second conveying section

[0095] 16. 16a-16c Porous evaporation component

[0096] 17. 17a-17d Heater for porous evaporation member

[0097] 18 Deflector

[0098] 19 Sublimation Room

[0099] 20 Cover

[0100] 21. Pressure measuring device

[0101] 22 Data processing device

[0102] 23 Subject

[0103] 24 Enter the opening

[0104] 25 Seals

[0105] 26 Launch Space

[0106] 110b Feed and evaporation unit

[0107] 200 Granular coating material in the first material storage section

[0108] 201, 201a-201c Granular coating material in porous evaporation component DETAILED DESCRIPTION

[0109] Figure 1 A schematic diagram of a first embodiment 100 of an evaporation device according to the present invention is shown. The evaporation device 100 comprises a first material storage 10, a first pressure and temperature sealed metering device 11, a first conveying section 12, a second material storage 13, a second pressure and temperature sealed metering device 14, a second conveying section 15, a porous evaporation member 16, at least one heater 17, a sublimation chamber 19, a cover plate 20, a pressure measuring device 21 and a data processing device 22.

[0110] The granular coating material 200 is stored in the first material storage 10 at a temperature of T1 and a pressure of p1. The first pressure and temperature sealed metering device 11 provides the granules of the granular coating material 200 to the second material storage 13 via the first conveying section 12, while sealing and isolating the first material storage 10 from the first conveying section 12 and the second material storage 13 in terms of temperature and pressure. The provided granular coating material 200 is contained in the second material storage 13 at a temperature of T2 and a pressure of p2. The pressure in the first conveying section 12 is also p2, and the temperature may have a gradient from T1 to T2 along the first conveying section 12 extending between the first pressure and temperature sealed metering device 11 and the second material storage 13. The second pressure and temperature sealed metering device 14 provides the granular coating material 200 to the porous evaporation member 16 via the second conveying section 15, while sealing and isolating the second material storage 13 from the second conveying section 15 in terms of temperature and pressure. The pressure within the second delivery section 15 is p3 , and the temperature may have a gradient from T2 to T3 along the second delivery section 15 extending between the second pressure and temperature sealing metering device 14 and the inlet of the porous evaporation member 16 .

[0111] The porous evaporation member 16 is connected to the second conveying section 15 so that the granular coating material 200 can enter the porous evaporation member 16. The temperature of the granular coating material 200 when entering the porous evaporation member 16 is T3. The porous evaporation member 16 is surrounded by at least one heater 17, which is arranged at a predetermined distance from the porous evaporation member 16 and heats the coating material in the porous evaporation member 16 to a temperature T4, so that the coating material evaporates at the temperature T4. That is, T4 is equal to or higher than the evaporation temperature or sublimation temperature of the coating material. The porous evaporation member 16 has a long extension along its longitudinal axis, which is arranged vertically in the 100 evaporation device of the first embodiment, and the heater 17 is arranged parallel to the longitudinal axis of the porous evaporation member 16. The upper end of the porous evaporation member 16 is open and forms an inlet for the particles of the coating material 200 to enter the porous evaporation member 16. The lower end of the porous evaporation member 16 is closed, and in the process of the coating material particles moving downward, the unevaporated particles are accumulated here to form an accumulation area. That is, the granular coating material 201 may be retained in the accumulation region at the bottom of the porous evaporation member 16 until the granular coating material 201 is completely evaporated. The granular coating material 201 may be the same as the granular coating material 200 in the first material storage portion 10 (eg, Figure 2A), but may also be different in size or shape from the granular coating material 200 due to passing through the first pressure and temperature sealing metering device 11 and the second pressure and temperature sealing metering device 14. Therefore, even the particles entering the porous evaporation member 16 at the upper end of the porous evaporation member 16 may be particles of the granular coating material 201, rather than particles of the granular coating material 200.

[0112] In the interior of the porous evaporation member 16, a guide plate 18 is arranged, and the guide plate 18 extends toward the interior thereof along the inner wall of the porous evaporation member 16 at an angle greater than 0° (zero) and less than 90°, wherein the angle is measured downward. The guide plates 18 extending from the opposite inner side walls of the porous evaporation member 16 are staggered and deflect the particles of the inclined coating material so that the travel path of these particles in the porous evaporation member 16 is increased. Therefore, the coating material can be evaporated even before reaching the lower end of the porous evaporation member 16. The porous evaporation member 16 and the heater 17 are arranged in the sublimation chamber 19. The side walls of the porous evaporation member 16 (the side walls extending along the longitudinal axis of the porous evaporation member 16) are formed of a porous material so that the evaporated coating material can penetrate the side walls and can enter the sublimation chamber 19.

[0113] In order to prevent the redeposition, i.e. condensation, of the evaporated coating material, the temperature in the sublimation chamber 19 is maintained at T4. The evaporated coating material (i.e., gaseous coating material particles) leaves the sublimation chamber 19 via the opening in the cover plate 20 and is deposited on the surface of the substrate (not shown) below the cover plate 20. The pressure p4 in the sublimation chamber 19 depends on the amount of gaseous coating material particles in the atmosphere in the sublimation chamber 19. The pressure measuring device 21 arranged in the sublimation chamber 19 can measure the pressure p4 and transmit its measurement result to the data processing device 22, which controls the second pressure and temperature sealing metering device 14 according to the pressure p4. Specifically, the amount of the particulate coating material 200 provided from the second material storage portion 13 to the porous evaporation member 16 is controlled by the second pressure and temperature sealing metering device 14. The measurement data and control signals transmitted between the pressure measuring device 21 and the data processing device 22 and between the data processing device 22 and the second pressure and temperature sealing metering device 14 can be transmitted by wire or wirelessly.

[0114] The evaporation device 100 can include further sensors, such as temperature sensors or further pressure sensors, which can also transmit their measurement results to the data processing device 22, which can in turn control further components based on the measurement results. The further components can be, for example, the heater 17, a further heater, the first pressure and temperature sealing metering device 11 or a pump.

[0115] Despite Figure 1In the evaporation device 100 shown, the first conveying section 12 and the second conveying section 15 are arranged vertically, but in other embodiments, the first conveying section 12 and the second conveying section 15 can also be arranged at an inclined angle relative to the vertical line and the horizontal line, as long as the conveying of the granular coating material 200 is ensured (for example, conveying by sliding rather than dropping or falling).

[0116] Figure 2A FIG. 1 is a schematic diagram of a second embodiment 101 of an evaporation device according to the present invention. Figure 1 The difference of the evaporation device 100 shown is that the porous evaporation member 16 is arranged horizontally. That is, the longitudinal axis of the porous evaporation member 16 extends horizontally instead of vertically. The porous evaporation member 16 is provided with an inlet opening connected to the second conveying section 15, which can receive the granular coating material 200 provided by the second pressure and temperature sealing metering device 14. This will be explained in more detail later. The side ends (i.e. the ends relative to the longitudinal axis) of the porous evaporation member 16 are closed.

[0117] although Figure 2A The data processing device is not shown, but the evaporation device 101 may also comprise a data processing device, which may be a separate component or may be part of the pressure measuring device 21 or the second pressure and temperature sealing metering device 14 .

[0118] Figure 2B Shows Figure 2A A cross-sectional view of the sublimation chamber 19 along line AA. It can be seen that the porous evaporation member 16 is a tube with a circular cross section, wherein the granular coating material 201 accumulates at the lower side of the porous evaporation member 16. The porous evaporation member 16 is surrounded by four heaters 17a to 17d, which are arranged at a certain distance from the porous evaporation member 16.

[0119] Figure 3A The cross section along the first direction shows the Figure 2A 1. A view of an embodiment of a sublimation chamber 19 used in an evaporation apparatus 101. The first direction is the horizontal direction. Figure 3B Shows Figure 3Asectional view of the sublimation chamber along line BB (i.e., along the second direction perpendicular to the first direction in the horizontal direction). The sublimation chamber 19 is formed by a main body 23 made of graphite. The lateral ends of the porous evaporation member 16 (i.e., the ends at both ends of the longitudinal axis of the porous evaporation member 16) are fixed by the main body 23. The inlet opening 24 is formed in the main body 23 and in the porous evaporation member 16. The seal 25 is arranged between the main body 23 and the porous evaporation member 16 so that the interior of the porous evaporation member 16 is only connected to the inlet opening 17, but not to the emission space 26 of the sublimation chamber 19. The emission space 26 refers to the space where the evaporated coating material enters from the interior of the porous evaporation member 16 through the holes of the porous material of the porous evaporation member 16. The lower end of the emission space 26 is closed by the cover plate 20. The seal 25 does not have to be airtight, but must prevent solid particles from penetrating. The lower part of the seal 25 can be used as the accumulation area of ​​the porous evaporation member 16 as described above. Furthermore, the porous evaporation member 16 can even be formed by two separate tube sections, each of which is closed only at one end, wherein the open ends of the two tube sections are connected by a seal 25. The porous evaporation member 16 is surrounded by four heaters 17. A pressure measuring device 21 is also arranged in the emission space 26. Figure 3A and Figure 3B Not shown in FIG.

[0120] Figure 4 A shows a schematic diagram of a third embodiment 102 of the evaporation device of the present invention. The evaporation device 102 includes three feeding and evaporation devices 110b. Each feeding and evaporation device 110b includes a first material storage portion 10a to 10c, a first pressure and temperature sealed metering device, a first conveying section, a second material storage portion, a second pressure and temperature sealed metering device 14a to 14c, a second conveying section, a porous evaporation member 16a to 16c and at least one heater, wherein the components of each individual feeding and evaporation device 110b are in the above order (e.g. Figure 1 ) are connected to each other. Figure 4 In A, the dotted box represents a feed and evaporation device 110b. However, different feed and evaporation devices 110b can share a heater. The porous evaporation members 16a to 16c and the associated heaters are arranged in the same sublimation chamber 19. Therefore, the same or different coating materials in each first material storage portion 10a to 10c can be evaporated separately and enter the sublimation chamber 19. In this way, the expected gas components can be discharged from the sublimation chamber 19 through the cover plate 20. The data processing device 22 can control all the second pressure and temperature sealing metering devices 14a to 14c according to the measurement results of the pressure measuring device 21 or other sensors arranged in the sublimation chamber 19.

[0121] Figure 4B The sublimation chamber 19 is shown as being arranged Figure 4View of an exemplary embodiment of the porous evaporation members 16a - 16c and the heater 17 of different feed and evaporation devices in A. That is, Figure 4B The arrangement shown can be implemented according to the evaporation device 102 in the third embodiment. In the sublimation chamber 19, six porous evaporation members are arranged in a circle around the seventh porous evaporation member. The outer evaporation members (two of which are labeled 16a and 16b) can evaporate two different coating materials 201a and 201b, such as Cd and Te, where the porous evaporation members suitable for different coating materials are arranged alternately. The middle seventh porous evaporation member 16c can evaporate a third coating material 201c, such as a doping material like Se. The heater 17 can be arranged around and between the porous evaporation members 16a to 16c such that the corresponding porous evaporation members 16a to 16c reach the required evaporation temperature, i.e., the temperature required to evaporate or sublimate different coating materials.

Claims

1. A coating material evaporation device for solar cell production, the device comprising at least the following components: a) a first material storage portion, the first material storage portion is used to store granular coating materials under the conditions of temperature T1 and pressure p1; b) a first pressure and temperature sealing metering device; c) a first conveying section; d) a second material storage portion, the second material storage portion being used to receive the granular coating material under the conditions of a temperature of T2 and a pressure of p2; e) a second pressure and temperature sealing metering device; f) a second conveying section, wherein the pressure of the second conveying section is p3; g) a porous evaporation member and a heater, the porous evaporation member being adapted to receive the granular coating material at a temperature T3, The heater is used to heat the porous evaporation member to a temperature T4; h) a sublimation chamber, wherein the pressure inside the sublimation chamber is p4, and the porous evaporation member and the heater are arranged in the sublimation chamber; i) a cover plate, which is located at the lower side of the sublimation chamber and is provided with a gas discharge opening, The components are connected in sequence from a) to g), characterized in that: The first material storage is arranged to discharge a controllable amount of particles into the second material storage via the first pressure and temperature sealing metering device through the first conveying section; The second material storage portion is arranged to discharge a controllable amount of particles into the porous evaporation member through the second pressure and temperature sealing metering device through the second delivery section; the heater for the porous evaporation member being arranged to heat the porous evaporation member to a temperature required for evaporation of the particulate coating material; The porous evaporation member is arranged to enable evaporated coating material to enter the sublimation chamber through pores of the porous evaporation member; The cover plate is arranged to allow the evaporated coating material to escape from the opening of the cover plate; A pressure measuring device is arranged in the sublimation chamber for detecting the pressure in the sublimation chamber, and the second pressure and temperature sealing metering device can be controlled according to the pressure in the sublimation chamber.

2. The device according to claim 1, It is characterized in that For the stated temperatures, the following applies: T1 < T2 < T3 < T4.

3. The device according to any one of the preceding claims, It is characterized in that The first pressure and temperature sealing metering device is a rotary feeder.

4. The device according to any one of the preceding claims, It is characterized in that The second pressure and temperature sealing metering device is a rotary feeder, a valve, a spring clamp, an adjustable flow orifice or an adjustable flow path constriction device.

5. The device according to any one of the preceding claims, It is characterized in that The measured values ​​of the pressure measuring device are transmitted to a data processing device, which controls the second pressure and temperature sealing metering device and optionally also the first pressure and temperature sealing metering device.

6. The device according to any one of the preceding claims, It is characterized in that Other sensors are also arranged in the device so that the data processing device can further control the device, and temperature sensors are arranged in the sublimation chamber and / or the porous evaporation member so that the data processing device can further control the heater.

7. The device according to any one of the preceding claims, It is characterized in that The heater is disposed on one or more sides of the porous evaporation member and is substantially parallel to a longitudinal axis of the porous evaporation member.

8. The device according to any one of the preceding claims, It is characterized in that The longitudinal axis of the porous evaporation member is oriented vertically, the upper end of the porous evaporation member is open and connected to the second delivery section where the particulate coating material is introduced; the lower end of the porous evaporation member is closed.

9. The device according to any one of claims 1 to 8, It is characterized in that Alternating guide plates are arranged on the inner wall of the porous evaporation member, and the guide plates can reflect incident particles of the granular coating material multiple times to extend the flight distance in the porous evaporation member.

10. The device according to any one of claims 1 to 7, It is characterized in that The longitudinal axis of the porous evaporation member is arranged horizontally, and an inlet opening is provided between the ends of the porous evaporation member, the inlet opening being connected to the second delivery section where the particulate coating material is introduced, wherein both ends of the porous evaporation member are closed.

11. The device according to any one of the preceding claims, It is characterized in that A plurality of components a) to g) are associated with a common sublimation chamber.

12. The device according to claim 11, It is characterized in that The plurality of first material storage portions may store the same coating material or different coating materials.

13. The device according to any one of claims 1 to 10, It is characterized in that The plurality of components b) to g) are connected to the same first material storage portion, and the plurality of porous evaporation members are arranged in the same sublimation chamber or in different sublimation chambers.

14. Use of the device according to any one of the preceding claims, wherein the device can coat the surface of the substrate with a coating material by moving or placing the substrate below the gas discharge opening of the cover plate.

15. The use according to claim 14, It is characterized in that The substrate is a thin film solar cell substrate.

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