DE102011103788A1 - Device for surface treatment with a process steam - Google Patents

Abstract

The invention relates to a device (1) for treating a coating (22) applied to a surface (21) of a substrate (20) with the aid of a vaporous particle stream (23). The device (1) comprises a reaction chamber (2) for receiving the substrate (20) during the treatment process and a steam source (4) for generating the particle stream (23). In order to ensure a quick and thorough removal of the process steam (23) after completion of the treatment, the device (1) is provided with a steam separator (7) with a separation container (9), with the aid of which the steam particles (23) from the reaction chamber (2 ) can be removed. The separating container (9) advantageously comprises a plurality of separating stages (11) which are separated from one another by guide plates (12).

Description

The invention relates to a device for treating a coating applied to a substrate surface with a vaporous particle flow.

Solar cells usually contain a substrate made of glass or plastic, to which an active layer is applied. The active layer has the task to absorb solar radiation and convert it into electricity. The main constituent of the active layer in many thin-film solar cells is an I-III-VI ₂ semiconductor, in particular Cu (In, Ga) Se ₂ or CuInS ₂ . In order to achieve a high efficiency of these thin-film solar cells, a predetermined stoichiometric composition with as homogeneous a distribution as possible must be achieved during the production of the active layer. For this purpose, a thin layer of Cu, In and Ga, a so-called. CIG alloy is first generated on the solar cell substrate; this can be z. Example by means of a chemical or physical Dampfabscheideverfahrens, by sputtering or sputtering technology. Subsequently, this CIG thin film is exposed in a reaction chamber at an elevated temperature to a Se vapor, a hydrogen selenide gas (SeH ₂ gas) or a hydrogen sulfide gas (H ₂ S gas) to selenise or sulfurize the CIG thin film and thus to create the CIGS layer.

After completion of the selenization or sulfurization process, the process steam must be removed as quickly as possible and as completely as possible from the reaction chamber in order to be able to supply the coated substrate to the next process stage. The problem of the removal of excess selenium after the selenization of I-III-VI ₂ thin film layers, for example, in the DE 197 17 565 A1 treated. This document shows a selenization furnace in which a precoated substrate is to be treated with selenium vapor. To dissipate excess selenium vapor after the surface treatment, suggests the DE 197 17 565 A1 to divide the reaction space into two subspaces, which are interconnected by channels. The substrate is one of the subspaces, the selenium source is arranged in the other subspace. By deliberately increasing and decreasing the temperatures of the subspaces, after the treatment, the excess selenium (at least in part) can be returned to the subspace containing the selenium source.

In the DE 100 06 778 A1 , which deals with the heat treatment of CIS layers of solar cells, is described as problematic that excess selenium must be evaporated from the CIS layer, must be postselenated in the oven and evaporates on cooling the substrate on this. To solve this problem, a separate infrared heating of the space located above the CIS layer is proposed which causes the amount of selenium evaporating from the substrate to decrease. The evaporated selenium can settle only on the inside of the space above the CIS layer or on a metal band covering the CIS layer.

The DE 20 2009 006 288 U1 describes a vacuum pump used in the manufacture of photovoltaic cells. These pumps must be protected against ingress of process gases and vapors. For this purpose, fenders are provided in the feed of the pump. The process vapors to be pumped fall on these fenders on their way to the pump and can condense on them. The mudguards are arranged in the feeder in such a way that they can be easily and quickly replaced as needed.

Based on this prior art, the present invention seeks to improve a device for surface treatment of a substrate coating, in particular for the selenization or sulfurization of a CIG thin film, in such a way that the process vapors after treatment quickly and completely as possible from the Reaction chamber can be removed and the maintenance, which is caused by deposits of process vapors, can be reduced.

The object is solved by the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

Thereafter, the treatment apparatus comprises a reaction chamber and a vapor separator which can be connected to this reaction chamber and with the aid of which the process vapors can be removed from the reaction chamber. The vapor separator contains a separating vessel which is connected to the reaction chamber by closable passages.

During vapor treatment of the substrate coating, a vapor source contained in the reaction chamber generates a flow of process vapor which acts on the substrate coating; During this treatment process, the passages between the reaction chamber and separation vessel are closed. After completion of the treatment process, the passages to the separation vessel are opened, the process steam penetrates into the separation vessel and is condensed there. In this way, the process steam can be quickly and inexpensively removed from the process chamber. After that, the Passages to the separation vessel are closed again to prevent a return of the collected in the vapor separator process vapors in the process chamber. In this state, the process chamber (for example, for removal of the treated substrate) can be vented and / or opened without the risk that process steam will escape to the outside.

In an advantageous embodiment, the separation vessel comprises a plurality of separation stages, which are separated from one another by at least one guide plate. In this way, a multi-stage deposition of the process steam can be achieved, wherein the baffles ensure that the density of the vapor particles decreases from stage to stage, so that a protective gas, which is returned after passing through the last separation stage in the reaction chamber, only a minimum density contains vapor particles.

In a particularly advantageous embodiment, the baffle has a spiral shape, ie it has the shape of a helix ("spiral staircase") with a low pitch. The process steam then travels a long way as it flows through the separation vessel, where it sweeps along the spirally arranged baffle. In this way, the deposition rate of the vapor particles on the baffle is increased.

Furthermore, it is advantageous to provide the separation vessel with an inner container, which can be taken out of the separation vessel together with the possibly arranged in the separation vessel baffle. The inner container and the guide plate can then be subjected to a cleaning, in the course of which the deposited on the inner wall of the inner container and the baffle process material can be recovered and / or disposed of. Advantageously, the baffle is attached to the inner container in such a way that it can be easily separated from the inner container and cleaned or replaced separately.

In order to achieve an efficient separation of the process steam in the separation tank, it is expedient to make the walls of the separation tank and / or the inner container of the separation tank and / or the baffle coolable. By (local) reduction of the surface temperature in the separation tank, a fast and effective separation of the process steam in selected areas of the separation tank can be achieved. For rapid dissipation of the heat, which are introduced by deposited process particles in the wall of the separation vessel, the inner container and / or the baffle, it is also expedient to manufacture these components from a material with high thermal conductivity, such as a copper alloy.

Furthermore, it should be ensured that the process vapors precipitate in an easily cleaned or exchanged area of the separation vessel; In particular, it should be avoided that the process vapors are already deposited in the inlet channel of the separation vessel and / or in the region of the passages to the reaction chamber. For this purpose, these areas are advantageously provided with a heater with which these areas can be heated to a temperature above that Condensation temperature is.

The surfaces of the separation vessel, the inner container and / or the baffle, which are exposed to the process steam, are advantageously made of a material having a high chemical stability to the process steam. In a vapor separator in which a selenium-containing vapor is to be separated, it is expedient, for example, to coat the inner surfaces exposed to the process steam with nickel, wherein it has proved to be particularly advantageous to apply a plurality of nickel layers to these inner surfaces by means of a galvanic process.

In the following the invention will be explained in more detail with reference to two embodiments illustrated in the figures. Showing:

1 a schematic sectional view through a device according to the invention for treating a coated substrate with a particle vapor, wherein the device comprises a vapor separator for the separation of excess vapor particles after the treatment;

2 a schematic sectional view through the vapor separator of 1 ;

3a a sectional view through an alternative embodiment of the vapor separator with spiral baffle;

3b a detailed view of the spiral baffle of 3a ,

In the drawings, corresponding elements are denoted by the same reference numerals. The drawings illustrate a schematic embodiment and do not represent specific parameters of the invention. Furthermore, the drawings are merely illustrative of an advantageous embodiment of the invention and should not be interpreted in such a way as to limit the scope of the invention.

1 shows a schematic sectional view of a device 1 for performing a surface treatment of a substrate, such as in the manufacture of an I-III-VI ₂ thin film layer on a surface 21 a substrate 20 can be used. The substrate 20 may be in particular a glass sheet or a plastic film. The substrate 20 is with a thin layer 22 from Cu, In and Ga in a predefined stoichiometric composition, a so-called. CIG alloy, provided in the by means of the device 1 the particles of a group VI element, in particular selenium and / or sulfur, are to be integrated.

The device 1 includes a reaction chamber 2 in whose interior 3 several steam sources 4 which produce particles of a group VI element, in particular selenium and / or sulfur or selenium and / or hydrogen sulphide. These vaporous particles are in 1 with the reference number 23 characterized. The steam particles 23 move through the interior 3 the processing chamber 2 and react with the on the substrate 20 applied layer 22 CIG alloy to produce an I-III-VI ₂ thin film layer of the desired stoichiometric composition. The process can be done under a protective gas, at reduced pressure or in vacuum, which is why in the wall 6 the processing chamber 2 connections 25 for a vacuum pump 26 are provided.

The substrate 20 is using a conveyor 30 in a feed direction 13 through the steam source 4 generated stream of vaporous particles 23 moved through, the steam source 4 facing surface 21 of the substrate 20 and the layer thereon 22 is exposed to the particle flow. The feed direction 13 the conveyor 30 is in the sectional view of 1 arranged perpendicular to the plane of the drawing.

Is the steam treatment of the substrate coating 22 completed, so must the excess vapor particles 23 as quickly and thoroughly as possible from the reaction chamber 2 be removed. To achieve this is a vapor separator 7 with a separating tank 9 provided by a closable passage 8th to the reaction space 2 is flanged. The steam separator 7 is in the device in such a way 1 integrated, that the deposition of the steam or the vapor mixture only after the entry into the separation vessel 9 he follows. For this purpose is supply line 8a heatable, so this area 8a at a temperature above the condensation temperature of the vapor particles 23 can be held. Furthermore, the steam or the vapor mixture at low speed in the separation vessel 9 directed. After the steam particles 23 in the steam separator 7 As completely as possible, the residual gas can through an outlet 28a vented to the outside space. Alternatively, the residual gas through a return channel 28b in the reaction chamber 2 to be led back.

2 shows a detailed view of the separation vessel 9 of the 1 , The separation tank 7 has an entrance channel 8a to the entry of the vapor or vapor mixture to be separated (arrow 24a ) and the exit channel 28a to remove the residual gas (arrow 24b ) on. The entrance channel 8a is with a wall heating 18 provided with the help of the inlet channel 8a can be heated so that no steam particles 23 in this area of the vapor separator 7 drop. The separation tank 9 contains an inner container 10 slidable in the separator tank 9 is stored and one end in the separation vessel 9 arranged closable opening 9a from the separation tank 9 can be removed. Inside the separator tank 9 There are several separation stages 11 passing through baffles 12 are separated from each other. The baffles 12 are shaped in such a way that they maintain the continuous flow of the vapor separator 7 penetrating vapor particles 23 dissolve abruptly, leaving inside the separation vessel 9 a turbulent flow arises. The flow channel is through the separation steps 11 designed so that, despite the intensive changes in the flow shape and the flow rate of the vapor or vapor mixture no significant pressure increases can occur.

The walls 14 of the separation tank 9 can with the help of a cooling device 15 be cooled to a temperature which is substantially lower than the temperature of the deposited vapor or vapor mixture. To ensure this, the walls can 14 for example, with inner channels 16 be provided, through which a coolant circulates. Between the walls 14 of the separation tank 9 , the inner container 10 and the baffles 12 There is a high thermal conductivity, so that the inner container and the baffles 12 are much cooler than those in the separation vessel 9 entering steam particles 23 , This will ensure that the vapor particles 23 on the inner walls 10a of the inner container 10 and the baffles 12 condense.

The baffles 12 are on the displaceable in the separation vessel 9 stored inner container 10 fastened so that they work together with the inner container 10 from the interior of the separation vessel 9 be removed (arrow 9b ) and a cleaning station can be supplied, in which the inner container 10 and the baffles 12 of the separated vapor particles 23 can be cleaned.

3a and 3b show an alternative embodiment of a separation vessel 9 ' with a baffle 12 ' , which has the shape of a spiral staircase, that is designed spiral. This embodiment of the baffle 12 ' causes a laminar flow into the separation vessel 9 ' penetrating vapor particles 23 abruptly dissolves, leaving inside the separation vessel 9 ' a turbulent flow arises. At the same time ensures the helix shape of the baffle 12 ' in that, despite the intensive changes in the flow form and the flow velocity of the steam or vapor mixture, no relevant pressure increases occur. Through the successive turns of the baffle 12 ' becomes a variety of separation stages 11 ' educated. At the outer edge of the baffle 12 ' is also a spiral cooling coil 16 ' arranged, which is traversed by a cooling medium and by means of which (with the aid of an in 3a not shown cooling device) the baffle 12 ' can be cooled in order to achieve an efficient separation of the steam or vapor mixture. baffle 12 ' and cooling coil 16 ' form part of an inner container 10 ' slidable in the separator tank 9 is stored and has a closable opening 9a ' from the separation tank 9 ' can be removed. baffle 12 ' and cooling coil 16 ' can thus together from the interior of the separation vessel 9 ' be removed and fed to a cleaning station, in which the baffle 12 ' from the separated vapor particles 23 can be cleaned.

To clean the inner container 10 . 10 ' and the baffles 12 . 12 ' To facilitate and ensure a long service life, the materials used for this purpose are selected accordingly. In particular, one may be the stream of vapor particles 23 facing inner wall 10a of the inner container 10 . 10 ' and the baffles 12 . 12 ' be provided with suitable surface coatings. In an advantageous embodiment, the inner container 10 . 10 ' and the baffles 12 . 12 ' made of copper or a copper alloy and provided with a multiple coating of nickel. Such nickel layers are stable to selenium. Conveniently, three to four nickel layers are applied, each of which is about 40 microns thick. The nickel layers can be applied in particular by electroplating; Such nickel layers have a low porosity, so that it can be ensured that no continuous defects occur and the exposed to the process steam surfaces are effectively protected against this vapor.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19717565 A1 [0003, 0003]
• DE 10006778 A1 [0004]
• DE 202009006288 U1 [0005]

Claims (10)

Contraption ( 1 ) for treating a person on a surface ( 21 ) of a substrate ( 20 ) applied coating ( 22 ) with a vaporous particle flow ( 23 ), - with a reaction chamber ( 2 ) for receiving the substrate ( 20 ) during the treatment process - and with a vapor source ( 4 ) for generating the particle stream ( 23 ), characterized in that the device ( 1 ) a vapor separator ( 7 ) with a separating container ( 9 . 9 ' ) for removing the vapor particles ( 23 ) from the reaction chamber ( 2 ) having. Contraption ( 1 ) according to claim 1, characterized in that the separating vessel ( 9 . 9 ' ) several separation stages ( 11 . 11 ' ) by at least one baffle ( 12 . 12 ' ) are separated from each other. Contraption ( 1 ) according to claim 2, characterized in that the baffle ( 12 ' ) is spirally shaped, so that successive turns of the baffle ( 12 ' ) successive separation stages ( 11 ' ) form. Contraption ( 1 ) according to claim 2 or 3, characterized in that the separating vessel ( 9 . 9 ' ) an inner container ( 10 . 10 ' ) through a closable opening ( 9a ) of the separation vessel ( 9 . 9 ' ) from the separation vessel ( 9 . 9 ' ) is removable. Contraption ( 1 ) according to one of claims 2 to 4, characterized in that the inner container ( 10 . 10 ' ) and / or the baffle ( 12 . 12 ' ) At least partially consist of a copper alloy. Contraption ( 1 ) according to one of claims 2 to 5, characterized in that the inner container ( 10 . 10 ' ) and / or the baffle ( 12 . 12 ' ) are at least partially provided with a nickel coating. Contraption ( 1 ) according to one of claims 2 to 6, characterized in that the walls ( 14 ) of the separation vessel ( 9 ) are coolable. Contraption ( 1 ) according to one of claims 2 to 7, characterized in that the inner container ( 10 . 10 ' ) and / or the baffles ( 12 . 12 ' ) are coolable. Contraption ( 1 ) according to claim 8, characterized in that the spiral baffles ( 12 ' ) with a spiral cooling coil ( 16 ' ) is provided. Contraption ( 1 ) according to one of the preceding claims, characterized in that an inlet channel ( 8a ) of the vapor separator ( 7 ) is heatable.

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