TWI385261B - Evaporator and liquid level controlling device and method adapted for an evaporator - Google Patents

Description

Evaporator and liquid level control device and method suitable for evaporator

The present invention relates to an evaporator and a liquid level control device and method, and more particularly to an evaporator and a liquid level control device and method for effectively controlling the liquid level of a liquid of a crucible and maintaining the liquid level at a substantially fixed height.

CIGS (copper indium gallium (di) selenide) is a compound semiconductor in a thin film solar cell. CIGS is in the form of a polycrystalline film, which is a group of three or five compound semiconductor materials composed of copper, indium, gallium and selenium. Figure 1A shows a schematic diagram of one of the steps in the fabrication of a CIGS thin film solar cell. Figure 1B shows a schematic diagram of one of the steps in the fabrication of a CIGS thin film solar cell. As shown in FIG. 1A, the CIGS thin film solar cell 10 includes a glass substrate 11. A molybdenum metal layer 12, a copper gallium metal layer 13, an indium metal layer 14, and a selenium layer 15 are sequentially deposited on the glass substrate 11. As shown in FIG. 1B, after the annealing treatment of the CIGS thin film solar cell 10 of the step of FIG. 1A, the copper gallium metal layer 13, the indium metal layer 14 and the selenium layer 15 form a CIGSe metal layer 16.

Fig. 2A is a schematic view showing the structure between a crucible and a gas pipe of a conventional selenium evaporator. As shown in FIG. 2A, the selenium evaporator 100 includes at least one crucible 110, at least one first intake pipe 121, at least one second intake pipe 122, and an exhaust pipe 123. The crucible 110 defines a space into which a selenium liquid 111 that has been melted is injected, and an upper portion of the space is filled with selenium vapor 112 that has been evaporated. The space defined by the crucible 110 is in communication with the first intake pipe 121 and the second intake pipe 122. In the step of vapor-depositing the selenium layer, the first process gas (for example, using nitrogen (N2)) is introduced into the inlet end of the first intake pipe 121, and the first process gas flows into the crucible 110 to discharge the selenium vapor 112. Thereafter, the selenium vapor 112 is passed to the second intake pipe 122. A second process gas is introduced into the intake end of the second intake pipe 122 (for example, nitrogen (N2) is also used) to drive the selenium vapor 112 to flow out from the outlet of the second intake pipe 122. The selenium vapor 112 is discharged from the outlet end of the second intake pipe 122 with the first and second process gases, and contacts the glass substrate 11 placed near the outlet end of the second intake pipe 122, so that the selenium layer 15 is laminated on the glass. On the substrate 11.

Figure 2B shows a schematic diagram of the structure between a crucible and a dosing device of a conventional selenium evaporator. The selenium evaporator 100 further includes a feed device. The feeding device comprises a loading device 131 and a feeding tube 132. The loading device 131 is filled with a solid selenium raw material, and the selenium raw material enters the crucible 110 through the feeding tube 132, is heated by the crucible 110, and is melted to form a selenium liquid.

How to control the liquid level of the selenium liquid of the selenium evaporator 100 has been an unresolved problem. Two kinds of liquid level detecting methods are designed in the prior art, one is optical type and the other is probe type. According to the probe type detecting method, as shown in FIG. 2B, the selenium evaporator 100 further includes a liquid level sensor 140 disposed in the crucible 110 for controlling the liquid level of the selenium liquid. However, since the crucible 110 is in a high temperature state, the liquid level sensor 140 must use a special material resistant to high temperature, and the selenium is highly corrosive to the metal, and the metal of the liquid level sensor 140 will soon be in the selenium liquid during the test. Corrosive, so the liquid level cannot be controlled. On the other hand, according to the optical detection method, the optical sensor must pass light through a window of the crucible 110 to sense the liquid level, but the quartz window will soon adhere to the selenium and be atomized, failing to penetrate the light. Therefore, the liquid level cannot be detected.

If the liquid level of the selenium liquid in the crucible 110 cannot be correctly detected, the selenium evaporator 100 cannot automatically control the selenium feed amount that causes the selenium raw material to enter the crucible 110 by the feeding device, and the operator cannot know the current crucible 110. The liquid level of the selenium liquid until the thickness of the selenium liquid is evaporated, or the thickness of the selenium vapor deposition is reduced, it is known that the crucible 110 has no selenium liquid, and then is fed manually, thus producing a large number of defective products, and cannot be continuously produced. .

It is an object of an embodiment of the present invention to provide an evaporator and a level control device that effectively control the liquid level of the liquid in the crucible and maintain the liquid level at a substantially fixed height.

According to an embodiment of the invention, a liquid level control device includes a first crucible, a second crucible, and an air tube. The first crucible is used to melt a substance into a liquid, and is connected to the outside to allow a process gas to pass into the first crucible and carry away the vapor of the substance in the first crucible. The second crucible is used to melt the substance into a liquid and communicate with the first crucible so that the liquid of the second crucible flows into the first crucible. The trachea includes a first open end and a second open end. The first open end is disposed in the second crucible, the second open end is disposed in the first crucible, and when the liquid level in the first crucible is lower than the second open end of the trachea, the space in the second crucible The space in the first crucible is communicated through the air tube to the space in the first crucible. When the liquid level in the first crucible is higher than the second open end of the trachea, the space in the second crucible forms a confined space.

According to an embodiment of the invention, an evaporator is provided for vapor deposition of a substance onto a substrate. The evaporator includes a liquid level control device, a first intake pipe and an exhaust pipe. The liquid level control device comprises a first crucible, a second crucible and an air tube. The first crucible is used to melt the substance into a liquid, and the second crucible is used to melt the substance into a liquid and communicate with the first crucible so that the liquid of the second crucible flows into the first crucible. The trachea includes a first open end disposed in the second crucible and a second open end disposed in the first crucible. When the liquid level of the liquid in the first crucible is lower than the second open end of the trachea, the space in the second crucible is communicated with the space in the first crucible through the trachea, when the liquid level in the first crucible is high At the second open end of the trachea, the space within the second crucible forms a confined space. The first intake pipe is connected to the first crucible, so that a first process gas is introduced into the first intake pipe, and the vapor of the substance in the first crucible is taken away to contact the substrate. The exhaust pipe is adapted to discharge the vapor of the first process gas and the substance flowing out of the first crucible into the evaporator.

According to an embodiment of the invention, the liquid level of the liquid of the first crucible can be effectively controlled, the liquid level can be maintained at a substantially fixed height, the stability of the vapor deposition step can be increased, and the difference in film thickness after evaporation can be more uniform. And can achieve automatic control, reducing the cost of manual control.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein. The above and other objects, features, and advantages of the invention will be apparent from

Figure 3 shows a liquid level control device suitable for use in a selenium evaporator in accordance with an embodiment of the present invention. As shown in FIG. 3, a liquid level control device 200 suitable for a selenium evaporator is suitable for being installed in a selenium evaporator and for controlling the liquid level of the selenium liquid in the selenium evaporator. The liquid level control device 200 suitable for the selenium evaporator includes a first crucible 210, a second crucible 220, and a gas tube 240. The second crucible 220 is in communication with the first crucible 210, whereby the selenium liquid in the second crucible 220 flows into the first crucible 210. The air tube 240 is connected between the second crucible 220 and the first crucible 210. More specifically, the first open end 241 of the trachea 240 is disposed at a position higher than the liquid level of the selenium liquid of the second crucible 220, the trachea The second open end 242 of the 240 is disposed in the first crucible 210. When the liquid level L1 of the selenium liquid in the first crucible 210 is lower than the second open end 242 of the air tube 240, the second crucible 220 defines The space communicates with the space in the first crucible 210 through the air tube 240. In this embodiment, the liquid level of the selenium liquid in the second crucible 220 is higher than the liquid level of the selenium liquid in the first crucible 210, and the selenium liquid in the second crucible 220 flows into the first due to gravity. The crucible 210 raises the liquid level of the selenium liquid in the first crucible 210.

When the liquid level L2 of the selenium liquid in the first crucible 210 rises above the second open end 242 of the air tube 240, the second open end 242 is blocked, and the space defined by the second crucible 220 can no longer pass through the air tube 240. The atmosphere is connected to the outside, so the space 221 defined by the second crucible 220 forms a closed space. At this time, if the selenium liquid in the second crucible 220 continues to flow into the first crucible 210, the air pressure in the space 221 in the second crucible 220 may be lower than the air pressure outside the second crucible 220, due to external air pressure. The selenium liquid in the second crucible 220 can no longer flow into the first crucible 210, so that the liquid level of the selenium liquid of the first crucible 210 is substantially maintained at the height of the second open end 242 of the air tube 240.

In the step of vapor-depositing the selenium layer, the selenium liquid of the first crucible 210 is evaporated into sevapor vapor (Se vapor), and the selenium vapor is discharged from the first crucible 210 with the process gas (for example, using nitrogen (N 2 )), selenium After the vapor is discharged, the liquid level of the selenium liquid of the first crucible 210 is lowered until the liquid level L1 of the selenium liquid in the first crucible 210 is lower than the second open end 242 of the air tube 240, and the second crucible 220 defines The space can again communicate with the atmosphere outside the second crucible 220 through the air tube 240, and the selenium liquid in the second crucible 220 can flow into the first crucible 210 again, so that the liquid level of the selenium liquid in the first crucible 210 rises. high. With this design, the liquid level control device 200 suitable for the selenium evaporator can maintain the liquid level of the selenium liquid of the first crucible 210 substantially at the height of the second open end 242 of the air tube 240. In addition, if it is necessary to adjust the liquid level of the selenium liquid of the first crucible 210 due to the process requirements, it is only necessary to adjust the height of the second open end 242.

In addition, in an embodiment, the liquid level control device 200 of the selenium evaporator may further include a feeding device 230, and the feeding device 230 is connected to the second crucible 220 through a valve, when the selenium raw material is to be put into the second crucible. In the pot 220, the valve is opened to allow the selenium raw material to enter the second crucible 220. When the valve is closed and the liquid level L2 of the selenium liquid in the first crucible 210 is higher than the second open end 242 of the air tube 240, the space defined by the second crucible 220 still forms a confined space.

4 is a schematic view showing the structure of a liquid level control device and a gas pipe of a selenium evaporator according to an embodiment of the present invention. As shown in FIG. 4, according to an embodiment of the invention, the selenium evaporator 300 includes at least one liquid level control device 200, at least one first intake pipe 121, at least one second intake pipe 122, and an exhaust pipe 123. The liquid level control device 200 includes a first crucible 210, a second crucible 220, and a gas tube 240. The second crucible 220 is in communication with the first crucible 210, whereby the selenium liquid in the second crucible 220 flows into the first crucible 210. The first open end 241 of the air tube 240 is disposed at a portion of the second crucible 220 above the liquid level of the selenium liquid, and the second open end 242 of the air tube 240 is disposed in the first crucible 210. The space defined by the first crucible 210 is in communication with the first intake pipe 121 and the second intake pipe 122. In the step of vapor-depositing the selenium layer, the first process gas (for example, using nitrogen (N2)) is introduced into the inlet end of the first intake pipe 121, and the first process gas flows into the first crucible 210 to remove the selenium vapor. After the discharge, the selenium vapor is introduced into the second intake pipe 122. A second process gas is introduced into the intake end of the second intake pipe 122 (for example, nitrogen (N2) is also used) to prevent the selenium vapor from being discharged from the intake end of the second intake pipe 122. The selenium vapor is discharged from the outlet end of the second intake pipe 122 with the first and second process gases, and contacts the glass substrate 11 placed near the outlet end of the second intake pipe 122, so that the selenium layer 15 is laminated on the glass substrate. 11 on.

In one embodiment, the first crucible 210 may be provided with a plurality of openings, and the second open end 242 of the air tube 240 is connected to the openings through a plurality of valves 243, and the opening and closing of the valves 243 may be controlled. The openings are selectively communicated to the second open end 242 of the air tube 240. With this design, the liquid level of the selenium liquid of the first crucible 210 can be controlled by controlling the valves 243.

According to an embodiment of the invention, a method of controlling a selenium level is provided, comprising the following steps.

Step S01: Melting selenium in the first crucible to form liquid selenium, which has a first selenium level.

Step S02: Melting selenium in the second crucible to form liquid selenium having a second selenium liquid level higher than the first selenium liquid level.

Step S03: The liquid is separated from the first crucible into the second crucible by a connecting tube, so that the liquid selenium in the second crucible can flow into the first crucible.

Step S04: connecting a first selenium level of the first crucible to a second selenium level of the second crucible with a gas pipe, and forming a seal above the second selenium level of the second crucible The space, when the first selenium level in the first crucible rises to reach the trachea, stops because the atmosphere cannot enter above the second selenium level.

Due to the evaporation machine used for evaporation, usually in the case of extremely high temperature, in the prior art, there is still a lack of effective control of the height of the metal or non-metal melted in the crucible, especially the evaporation of selenium must be greater than It is carried out at 300 ° C, and selenium is extremely corrosive to all metals, so the prior art cannot control its liquid level. According to an embodiment of the invention, the liquid level of the metal or non-metal liquid of the first crucible 210 can be effectively controlled, and the liquid level can be maintained at a substantially fixed height, thereby increasing the stability of the metal or non-metal evaporation step, and evaporating After the film thickness difference is more uniform, the product yield is improved, and automatic control can be achieved, reducing the cost of manual control.

While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention.

10. . . CIGS thin film solar cell

100. . . Selenium evaporator

11. . . glass substrate

110. . . Shabu-shabu

111. . . Selenium liquid

112. . . Selenium vapor

12. . . Molybdenum metal layer

121. . . First intake pipe

122. . . Second intake pipe

123. . . exhaust pipe

13. . . Copper gallium metal layer

131. . . Loading device

132. . . Feed tube

14. . . Indium metal layer

140. . . Liquid level sensor

15. . . Selenium layer

16. . . CIGSe metal layer

200. . . Liquid level control device

210. . . First shabu-shabu

220. . . Second shabu-shabu

221. . . space

230. . . Feeding device

240. . . trachea

241. . . First open end

242. . . Second open end

243. . . valve

300. . . Selenium evaporator

Figure 1A shows a schematic diagram of one of the steps in the fabrication of a CIGS thin film solar cell.

Figure 1B shows a schematic diagram of one of the steps in the fabrication of a CIGS thin film solar cell.

Fig. 2A is a schematic view showing the structure between a crucible and a gas pipe of a conventional selenium evaporator.

Figure 2B shows a schematic diagram of the structure between a crucible and a dosing device of a conventional selenium evaporator.

Figure 3 shows a liquid level control device suitable for use in a selenium evaporator in accordance with an embodiment of the present invention.

4 is a schematic view showing the structure of a liquid level control device and a gas pipe of a selenium evaporator according to an embodiment of the present invention.

200. . . Liquid level control device

210. . . First shabu-shabu

220. . . Second shabu-shabu

221. . . space

230. . . Feeding device

240. . . trachea

241. . . First open end

242. . . Second open end

Claims (10)

An evaporator suitable for evaporating a substance onto a substrate, comprising: a liquid level control device comprising: a first crucible for melting the substance into a liquid; and a second crucible for Dissolving the substance into a liquid and communicating with the first crucible, thereby flowing the liquid of the second crucible into the first crucible; and an air tube comprising: a first open end disposed in the second crucible, And a second open end is disposed in the first crucible, and when the liquid level of the liquid in the first crucible is lower than the second open end of the trachea, the space in the second crucible is communicated through the trachea In the space in the first crucible, when the liquid level of the liquid in the first crucible is higher than the second open end of the trachea, the space in the second crucible forms a confined space; a first intake a tube connected to the first crucible to pass a first process gas into the first intake pipe, carrying away the vapor of the substance in the first crucible to contact the substrate; and exhausting And a tube adapted to discharge the first process gas flowing out of the first crucible and the vapor of the substance out of the evaporator. The evaporator of claim 1, wherein the first open end of the gas pipe is disposed at a portion of the second crucible that is higher than a liquid level. The evaporator of claim 1, wherein the liquid level of the liquid in the second crucible is higher than the liquid level of the liquid in the first crucible. The evaporator of claim 1, wherein the first crucible is provided with a plurality of openings, and the second open end of the trachea is connected to the openings through a plurality of valves, respectively. The evaporator of claim 1, further comprising: a second intake pipe connected to the first intake pipe and comprising: an air inlet adapted to pass a second process gas; . An exhaust port, the substrate is placed adjacent to the exhaust port. A liquid level control device comprising: a first crucible for melting the substance into a liquid, communicating with the outside thereof to allow a process gas to pass into the first crucible, and taking the first crucible a vapor of the substance; a second crucible for melting the substance into a liquid, and communicating with the first crucible, thereby allowing the liquid of the second crucible to flow into the first crucible; and a trachea The method includes: a first open end is disposed in the second crucible, and a second open end is disposed in the first crucible, and when the liquid level of the liquid in the first crucible is lower than the second of the trachea When the open end is, the space in the second crucible is communicated with the space in the first crucible through the air tube. When the liquid level in the first crucible is higher than the second open end of the trachea, The space inside the second crucible forms a confined space. The liquid level control device according to claim 6, wherein the first open end of the air tube is disposed at a position of the second crucible higher than a liquid level. The evaporator of claim 6, wherein the liquid level of the liquid in the second crucible is higher than the liquid level of the liquid in the first crucible. The liquid level control device of claim 6, wherein the first crucible is provided with a plurality of openings, and the second open end of the air tube is connected to the openings through a plurality of valves, respectively. A method for controlling a selenium level, comprising: melting selenium in a first crucible to form liquid selenium having a first selenium level; melting selenium in a second crucible to form liquid selenium having a second selenium a bit higher than the first selenium level; communicating from the first crucible to the second crucible in a communicating tube to allow liquid selenium in the second crucible to flow into the first crucible; The first selenium level of the first crucible is connected to the second selenium level of the second crucible by a gas pipe, and a sealing is formed above the second selenium level of the second crucible The space is such that when the first selenium level in the first crucible rises to reach the trachea, the atmosphere stops because the atmosphere cannot enter the second selenium level.