DE102013102074A1 - System for coating substrates with polycrystalline silicon, comprises many process chambers for coating substrates with amorphous silicon and at least one lock for injecting and discharging substrates in process chambers - Google Patents

Abstract

System (10) for coating substrates with polycrystalline silicon, comprises many process chambers (18) for coating substrates with amorphous silicon for thermal desorption of hydrogen and for converting the amorphous silicon layer using a laser into a polycrystalline silicon layer, and at least one lock (12) for injecting and discharging substrates in the process chambers. At least one process chamber is present as a coating chamber (14) for vacuum coating of substrates with amorphous silicon. At least one process chamber is formed from the silicon layer for the thermal desorption of hydrogen. System (10) for coating substrates with polycrystalline silicon, comprises many process chambers (18) for coating substrates with amorphous silicon for thermal desorption of hydrogen and for converting the amorphous silicon layer using a laser into a polycrystalline silicon layer, and at least one lock (12) for injecting and discharging substrates in the process chambers. At least one process chamber is present as a coating chamber (14) for vacuum coating of substrates with amorphous silicon. At least one process chamber is formed from the silicon layer for the thermal desorption of hydrogen. At least one process chamber is formed as a laser chamber (20) for converting the amorphous silicon layer into a polycrystalline silicon layer using a laser beam, The process chambers are operated under vacuum or inert gas, and the process chambers are coupled to each other. The steps of coating with amorphous silicon, thermal desorbing of hydrogen and conversion into polycrystalline silicon layer are carried out successively without an intermediary discharge from the system. An independent claim is also included for coating the substrates with polycrystalline silicon, comprising transferring substrates into the system having many process chambers, which are hermetically coupled to each other, vacuum coating the substrates having amorphous silicon layer in at least one of the process chambers, heating the substrates for thermal desorption of hydrogen from the silicon layer, and melting the amorphous silicon layer by means of laser for converting into the polycrystalline silicon layer.

Description

The invention relates to a system and a method for coating substrates with polycrystalline silicon.

The coating of substrates with polycrystalline silicon is required on a large scale in order to produce, for example, TFT displays, LCD displays or OLEDs.

From the US Pat. No. 4,603,497 B1 For example, it is generally known to first apply an amorphous silicon coating on a substrate surface, for example by a PCVD method, then to remove hydrogen by a heating step and finally thermally convert the amorphous silicon layer into a polycrystalline silicon layer by means of a further heating step.

The application with CVD or PCVD takes place at about 600 ° C, the hydrogen removal between 400 ° C and 500 ° C over a period of about 30 min. Thereafter, a conversion of the amorphous silicon in polycrystalline silicon at about 1000 to 1200 ° C, wherein still isolation steps for the formation of TFT electrodes can be interposed.

Such high temperatures are of great disadvantage for today's displays. Insofar as the substrate is glass, to avoid damage to the glass, the temperatures should not exceed 250 to 300 ° C., preferably 250 ° C., since otherwise adverse effects on the glass structure can not be ruled out. As far as plastics are used as substrates, of course, the temperature is strictly limited to a maximum of about 200 ° C, with only a few plastics are known that allow a temperature up to about 250 ° C.

From the WO 01/59818 A1 It is known to generate defined polycrystalline silicon regions in an amorphous silicon layer using an excimer laser. For this purpose, first an insulating layer and then a layer of doped amorphous silicon are applied. To generate electrically conductive regions, an electromagnetic radiation is carried out with a laser source, in particular an excimer laser, wherein a shadow mask for defining the contours of the electrically conductive regions is positioned between the substrate having the layer and the laser source. The laser irradiation locally converts the amorphous silicon layer into polycrystalline silicon.

However, such a method is suitable only for the local conversion of amorphous silicon into polycrystalline silicon, but not for the production of planar coatings of polycrystalline silicon.

From the WO 2010/069287 A2 It is known to deposit a microcrystalline silicon layer on a substrate directly in a plasma chamber system, wherein a substrate temperature between 100 ° C and 350 ° C is selected. By a special process control with a deposition rate of> 0.5 nm / s, the microcrystalline layer with a thickness of less than 1000 nm is deposited directly on the substrate using a PECVD method. The process is particularly suitable for solar cell production, wherein the microcrystalline silicon, which is doped with hydrogen, is used as the absorber material.

Against this background, the invention has for its object to provide a system and a method for coating substrates with polycrystalline silicon, which can be produced on a large scale polycrystalline silicon layers of high quality with short lead times and the lowest total cost on substrates. In this case, too high temperatures that could damage the substrates should be avoided. Furthermore, the plant and the method should be particularly suitable for the production of polycrystalline silicon layers, as used on TFT displays, LCD displays or OLED displays.

This object is achieved by a plant for coating substrates with polycrystalline silicon, comprising a plurality of process chambers for coating substrates with amorphous silicon, for the thermal desorption of hydrogen and for converting the amorphous silicon layer by means of a laser in a polycrystalline silicon layer, and at least one sluice for introducing and discharging substrates into the process chambers, wherein at least one process chamber is designed as a coating chamber for vacuum deposition of substrates with amorphous silicon, wherein at least one process chamber for thermal desorption of hydrogen from the silicon layer is formed, and at least one process chamber as a laser chamber is formed for converting the amorphous silicon layer into a polycrystalline silicon layer by means of a laser beam, wherein the process chambers are operable under vacuum or inert gas, and wherein the process chambers so mi coupled to each other, that the steps of coating with amorphous silicon, thermal desorbing of hydrogen and conversion into a polycrystalline silicon layer are successively without an interim discharge from the plant feasible.

• – Einschleusen von Substraten in eine Anlage mit mehreren Prozesskammern, die luftdicht miteinander koppelbar sind,
• – Vakuumbeschichten der Substrate mit einer amorphen Siliziumschicht in zumindest einer der Prozesskammern,
• – Aufheizen der Substrate zur thermischen Desorption von Wasserstoff aus der Siliziumschicht, und
• – Aufschmelzen der amorphen Siliziumschicht mittels eines Lasers zur Umwandlung in eine polykristalline Siliziumschicht.

The invention is further achieved by a method of coating polycrystalline silicon substrates with the following steps:

• Introduction of substrates into a system having a plurality of process chambers which can be coupled airtight to one another,
• Vacuum coating the substrates with an amorphous silicon layer in at least one of the process chambers,
• - Heating the substrates for the thermal desorption of hydrogen from the silicon layer, and
• - Melting of the amorphous silicon layer by means of a laser for conversion into a polycrystalline silicon layer.

The invention is completely solved in this way.

The fact that the individual process steps are carried out in chronological order within the various process chambers within a plant, without an interim discharge of substrates from the plant is required, results in a significantly simplified process management and increased quality of the coatings obtained compared to conventional processes in which the individual steps are carried out in individual plants and subsequently a discharge occurs, with further handling steps and washing steps between the individual process steps are required.

In an advantageous embodiment of the invention, the individual process chambers are coupled to each other such that a passage of substrates through the system takes place with a uniform timing.

This ensures a smooth process flow and high throughput.

In principle, any vacuum coating process is suitable for producing the amorphous silicon coating. These include, in particular, CVD, in particular PECVD methods, sputtering, the ALD method, the evaporation method (e-beam and thermal), the IBD method (ion beam deposition).

In a further preferred embodiment of the invention, the coating chamber has a heatable receiving table for receiving substrates, and an electrode above the receiving table and a gas supply for supplying process gases, preferably with outflow openings in the electrode.

Such a coating chamber is particularly suitable for carrying out a PECVD process, preferably using outflow openings in the electrode according to the "shower-head principle".

The process chamber for the thermal desorption of hydrogen may be combined with the coating chamber or may be formed as a separate process chamber.

A higher throughput results when the process chamber for the thermal desorption of hydrogen is designed as a separate process chamber. If at least one process chamber designed as a heating chamber with heating elements, which is suitable for preheating substrates to a certain process temperature for the coating with amorphous silicon and / or for the laser treatment and / or for the thermal desorption of hydrogen, the heating chamber can specifically for preheating the Substrates and / or used for the thermal desorption of hydrogen, which may result in a better process matching between the individual process chambers.

According to a further embodiment of the invention, the laser chamber has a laser unit with an excimer laser, preferably with a wavelength of 308 nm, or a green light laser, preferably with a wavelength of 532 nm, and with an optical system for expanding the laser beam onto a strip, and means for relative movement between the laser unit and the substrates, preferably for moving the substrates relative to the laser unit.

With such an embodiment, the thermal conversion from amorphous silicon to polycrystalline silicon can be locally largely limited to the silicon coating, so that thermal damage to the underlying substrate can be largely avoided. As a result of the expansion of the laser beam onto a strip, a conversion of the amorphous silicon into a polycrystalline silicon layer can be achieved in a short time with large substrates.

Preferably, separating means, in particular closable bulkheads, are provided between some of the process chambers, preferably between all process chambers.

In this way, the individual processes in the various process chambers can be completely decoupled from each other, for example, the PECVD process, which takes place under vacuum, from a subsequent heating step for the thermal desorption of hydrogen, which can also be done under inert gas.

According to a further embodiment of the invention, the coating chamber has a heater for preheating the substrates to a temperature of about 150 to 220 ° C, preferably to about 180 to 210 ° C, more preferably to about 200 ° C for coating.

This ensures a coating at an optimum coating temperature.

According to a further embodiment of the invention, the various process chambers are arranged one behind the other, wherein a Einschleuskammer is provided for introducing substrates, subsequently a coating chamber for coating with amorphous silicon, a heating chamber for the thermal desorption of hydrogen, subsequently a laser chamber and a discharge chamber for discharging substrates are arranged. To generate a smoothly cycled pass some of the process chambers may be arranged in parallel. For example, if the process step of thermal desorption takes significantly longer compared to the coating with amorphous silicon, then two heating chambers for thermal desorption can be operated in parallel.

According to an alternative embodiment of the invention, a process chamber is designed as a central transfer chamber, which preferably also has heating elements, wherein the further process chambers are arranged in a star shape around the transfer chamber, and wherein preferably a common chamber is provided for the inward and outward transfer of substrates.

With such a star-shaped arrangement, a very high throughput and simultaneously flexible operation can be made possible.

Here, too, similar process chambers can be provided which can be operated in parallel for longer-lasting process steps in order to ensure uniform clocking through the entire system.

According to a further embodiment of the invention, the laser chamber has elements for preheating or cooling the substrates, preferably to a temperature of about 150 to 250 ° C, preferably to a temperature of about 180 to 220 ° C.

It has been found that the thermal conversion of the amorphous silicon layer into a polycrystalline silicon layer with the aid of the laser proceeds significantly more effectively if the substrates are preheated in a suitable manner.

According to a further embodiment of the invention, the process chambers are provided with a heating / cooling system, preferably with a fluid circuit, such as an oil circuit, to heat or cool the process chambers to a certain temperature, preferably to a temperature of 150 to 200 ° C, more preferably at a temperature of about 200 ° C.

By using such a heating / cooling system, the substrates can be kept better at an optimum temperature during the various process steps, resulting in a significantly higher overall process reliability and a higher quality of the coating.

As already mentioned, the coating with an amorphous silicon layer by means of a CVD method, preferably by means of a PECVD method, under vacuum at a coating temperature of 150 to 250 ° C, preferably from 180 to 220 ° C, more preferably at about 200 ° C be performed.

For this purpose, the substrates are preferably preheated to the coating temperature before coating or at least partially preheated to the coating temperature.

For coating, a mixture of silane (SiH ₄ ) and a protective gas, preferably argon, preferably with a mixing ratio of about 1: 3 to 1: 6, more preferably from about 1: 5 of silane to argon, preferably at a pressure of about 0.5 to 10 mbar, more preferably at a pressure of 1 to 5 mbar.

In this way, high-quality amorphous silicon layers can be applied.

For a layer thickness of about 50 nm, a coating time of about 0.3 to 3 minutes, preferably of about 0.5 to 1.5 minutes, more preferably of about 1 minute, is usually followed.

Alternatively, the amorphous silicon layer can also be produced by means of any other vacuum coating method, in particular by means of a sputtering method.

For the thermal desorption of hydrogen, the substrates are preferably heated to a temperature of about 150 to 300 ° C, preferably from about 180 to 250 ° C, more preferably to a temperature of about 200 to 220 ° C, and preferably about 0.5 to Held for 5 minutes, more preferably for about 1 to 3 minutes at this temperature.

More preferably, the substrates are in the still warm state in a laser chamber passed and treated there by means of an excimer laser, preferably at 308 nm, or by means of a green light laser, preferably with 532 nm, to convert the amorphous silicon layer into a polycrystalline silicon layer.

Preferably, during the laser treatment, the substrates are maintained at an average substrate temperature (as measured on their support surface on a substrate support) of about 100 to 250 ° C, preferably about 100 to 200 ° C, more preferably about 150 to 200 ° C.

It has been shown that in this way the laser process can be shortened and a particularly high quality can be ensured.

More preferably, during the laser treatment, the substrates are moved relative to a laser unit which outputs a linearly expanded laser beam, preferably at a speed of about 0.5 to 5 cm / s, more preferably 1 to 3 cm / s, more preferably about 1 to 2 cm / s.

In this way, a safe conversion of the amorphous silicon layer into a high-quality polycrystalline silicon layer can be ensured.

It is understood that the above-mentioned and below to be explained features of the invention not only in the particular combination, but also in other combinations or in isolation of the invention can be used without departing from the scope of the invention.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. Show it:

1 a first embodiment of a system according to the invention in linear arrangement in a schematic representation;

2 a second embodiment of a system according to the invention in a star-shaped arrangement with a central transfer chamber, in a schematic representation;

3 a simplified sectional view of a coating chamber for coating with amorphous silicon using the PECVD method;

4 a simplified schematic sectional view of an alternative coating chamber using a sputtering process for coating with amorphous silicon and

5 a simplified schematic representation of a laser chamber for converting the amorphous silicon coating in a polycrystalline silicon layer.

In 1 a first embodiment of a system according to the invention is shown schematically and in total with the numeral 10 designated.

The attachment 10 comprises a plurality of process chambers, which are arranged in a linear arrangement one behind the other, wherein the individual process chambers by separating means, such as in the form of movable bulkheads 26 , preferably airtight to each other are separable.

The individual substrates, such as glass substrates, such as those intended for TFT displays, pass through the system 10 in the direction of the arrows 11 . 25 ,

The attachment 10 has a Einschleuskammer 12 on, the outside airtight on a bulkhead 26 is closable. Below is a coating chamber 14 for coating the substrates with an amorphous silicon layer, for example by means of a PECVD method (cf. 3 ) or by means of a sputtering process (cf. 4 ) intended. This is followed by a heating chamber 16 with heating elements 18 which is provided for the thermal desorption of hydrogen from the preceding coating process. This is followed by a laser chamber 20 with a laser unit 22 at, under which the substrates are driven through. Subsequently, the substrates via a discharge chamber 24 from the plant 10 discharged again to the outside.

2 shows an alternative design of the system according to the invention, the total with numeral 10a is designated.

In contrast to the linear arrangement according to 1 this is an arrangement with a central transfer chamber 28 around which the remaining process chambers are arranged outwardly adjacent, so that, as shown here, results in a cross-shaped design. Alternatively, the transfer chamber could 28 Instead of a square base area also have a pentagonal or generally an octahedral shape, so that would join the outside of the transfer chamber a total of five or more process chambers.

Such an arrangement has in comparison to the arrangement according to 1 Overall, a higher flexibility and makes it easier to drive different processes in parallel.

The central transfer chamber 28 has here a handling device, by means of which the substrates can be moved on their substrate carriers in each case to the adjacent chamber. In addition, the transfer chamber is preferably with heating elements 18 provided so that in the transfer chamber also a preheating of substrates for subsequent processes can be performed, or a thermal desorption of hydrogen.

The transfer chamber is in front of all adjacent chambers each with a bulkhead 26 hermetically sealed, so that the individual processes can run independently.

In 2 schematically is a parallel arrangement of two coating chambers 14 . 30 shown what makes sense if the coating process takes longer than the thermal desorption of hydrogen. If, on the other hand, the thermal desorption of hydrogen and, possibly, preheating take longer than, say, the coating process, one of the two chambers, such as the chamber, could take longer 30 instead be designed as an additional heating chamber.

In 3 is a first embodiment of a coating chamber 14 shown schematically.

The coating chamber 14 has a housing 34 on, which is designed airtight and on a side wall a bulkhead 26 owns, that is a retraction or extension of substrates 44 on substrate carriers 42 allowed in the open state. The interior 32 the coating chamber 14 can via a suction line 36 and a connected vacuum pump 38 be evacuated.

The substrates 44 lie on a substrate holder 42 that by means of a drive 50 in the coating chamber 14 can be retracted, or can be extended from it and on a shooting table 46 can be stored. The shooting table 46 has a number of integrated heating elements 48 (For example, resistance heaters), which in the shooting table 46 are distributed and may be controlled individually or in groups, to allow the most uniform temperature distribution.

Above the shooting table 46 there is an electrode 52 , which is formed like a frame and in a number of gas outlet openings 54 are provided to process gases via a gas supply line 40 be fed as uniformly as possible in the direction of the substrate surface to emerge ("shower-head principle"). The shooting table 46 is doing as a counter electrode to the electrode 52 connected.

To about a 50 nm thick amorphous silicon layer on a glass substrate 44 to separate, become the substrates 44 by means of the heating elements 48 in the shooting table 46 preheated to a coating temperature of about 200 ° C, and then silane (SiH ₄ ) mixed with argon is fed. The mixing ratio of (SiH ₄ ) to argon is about 1: 5. The pressure is 1 to 5 mbar. For a layer thickness of about 50 nm, about 1 min coating time is sufficient.

Alternatively, a coating with an amorphous silicon layer by means of a sputtering process in a coating chamber 14a (see. 4 ) be performed.

This is done on an electrode 52 at close range above the substrates 44 is arranged, a target 56 made of silicon. The electrode 52 comes with an RF generator 58 coupled while the substrates 44 be switched as a counter electrode.

The interior 32 the coating chamber 14a is evacuated and it is a process gas, preferably argon, fed, which is converted by the RF voltage source in a plasma. The ions thus generated hit the target 56 a, resulting in an amorphous silicon layer on the substrates 44 separates.

After application of the amorphous silicon layer in one of the coating chambers 14 . 14a there is a thermal desorption of hydrogen, which either according to 1 in a specially provided for this heating chamber with heating elements 18 can be performed, or about according to 2 in the transfer chamber 28 , which is also equipped with appropriate heating elements.

The thermal desorption of hydrogen is carried out at 150 to 300 ° C, preferably at 180 to 250 ° C, preferably at about 200 to 220 ° C. In this case, a desorption time of 0.5 to 5 minutes, preferably from about 1 to 3 minutes is sufficient.

After thermal desorption, the amorphous silicon layer in the laser chamber 20 locally heated and converted into a polycrystalline silicon layer, wherein the underlying substrate 44 as little as possible thermally influenced.

5 shows a laser chamber 20 with an airtight lockable housing 34 into which the substrate carrier 42 with the bulkhead open 26 can be retracted or extended. Approximately in the middle of the laser chamber 20 is a laser unit on the ceiling 22 with a laser 60 and a coupled optics 62 intended. The optics 62 allows a widening of the laser beam on a Strip form. The substrates 44 can by means of the drive 50 under the laser unit 22 be driven through, so that the strip-shaped widened laser beam 64 gradually comes into contact with the entire substrate surface. The speed with which the substrates 44 are traversed under the laser unit is about 0.5 to 5 cm / s, preferably at 1 to 3 cm / s, more preferably at about 1 to 2 cm / s, or in particular at 1.5 cm / s.

The laser is either an excimer laser with a wavelength of 308 nm or a green light laser with a wavelength of 532 nm. The substrates are moved at a speed of preferably about 1.5 cm / s under the expanded laser beam.

It has been shown that it is advantageous if the substrates 44 for the laser step to a substrate temperature of about 100 to 250 ° C, preferably from about 100 to 200 ° C, more preferably preheated from about 150 to 200 ° C.

For this purpose there are one or more heating elements 66 in the entrance area of the laser chamber 20 , This may be, for example, IR emitters.

Preferably, the substrates become 44 from the previous thermal desorption process while still warm in the laser chamber 20 retracted, so that, if necessary, no further preheating for the laser process is necessary.

As a further alternative, all process chambers may be provided with a heating / cooling system, which is schematically shown in FIG 5 With 68 is indicated. Here, for example, in the housing 34 the individual process chambers tubes 70 run, is guided by a fluid that is at a suitable process temperature for the entire system 10 respectively. 10a is heated or cooled. In this way, all process chambers of the plant 10 respectively. 10a be kept at a particularly suitable for the individual process steps temperature, or 150 to 200 ° C, in particular to about 200 ° C.

Overall, the system is in accordance with 1 or according to 2 designed so that a uniform as possible timing is guaranteed by the entire system without delays.

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

• US 6403497 B1 [0003]
• WO 01/59818 A1 [0006]
• WO 2010/069287 A2 [0008]

Claims (23)

Plant for coating substrates with polycrystalline silicon, having a plurality of process chambers ( 12 . 14 . 16 . 18 . 20 . 24 . 28 . 30 . 14a ) for coating substrates ( 44 ) with amorphous silicon, for the thermal desorption of hydrogen and for converting the amorphous silicon layer by means of a laser ( 60 ) in a polycrystalline silicon layer, and with at least one lock ( 12 . 24 ) for introducing and removing substrates ( 44 ) into the process chambers ( 12 . 14 . 16 . 18 . 20 . 24 . 28 . 30 . 14a ), wherein at least one process chamber as a coating chamber ( 14 . 30 . 14a ) for vacuum coating of substrates ( 44 ) with amorphous silicon, wherein at least one process chamber ( 16 . 28 ) is formed for the thermal desorption of hydrogen from the silicon layer, and at least one process chamber as a laser chamber ( 20 ) for converting the amorphous silicon layer into a polycrystalline silicon layer by means of a laser beam, wherein the process chambers 12 . 14 . 16 . 18 . 20 . 24 . 28 . 30 . 14a ) are operated under vacuum or inert gas and wherein the process chambers ( 12 . 14 . 16 . 18 . 20 . 24 . 28 . 30 . 14a ) are coupled together in such a way that the steps of coating with amorphous silicon, thermal desorbing of hydrogen and conversion into a polycrystalline silicon layer successively without an interim discharge from the plant ( 10 . 10a ) are feasible. Plant according to claim 1, in which the individual process chambers ( 12 . 14 . 16 . 18 . 20 . 24 . 28 . 30 . 14a ) are coupled together in such a way that a passage of substrates ( 44 ) through the annex ( 10 . 10a ) takes place with a uniform timing. Plant according to Claim 1 or 2, in which the coating chamber ( 14 . 30 ) for CVD coating, in particular by means of a PECVD method is formed and a heated receiving table ( 46 ) for receiving substrates ( 44 ), and an electrode ( 52 ) above the receiving table ( 46 ) and a gas supply ( 40 ) for the supply of process gases, preferably with outflow openings ( 54 ) in the electrode ( 52 ). Plant according to one of the preceding claims, in which the process chamber for the thermal desorption of hydrogen with the coating chamber ( 14 . 30 ) or as a separate process chamber ( 16 . 28 ) is trained. Installation according to one of the preceding claims, in which at least one process chamber is used as heating chamber ( 16 . 28 ) with heating elements ( 18 ), which is used for preheating substrates ( 44 ) is designed for a specific process temperature for the coating with amorphous silicon and / or for the laser treatment and / or for the thermal desorption of hydrogen. Plant according to one of the preceding claims, in which the laser chamber ( 20 ) a laser unit ( 22 ) with an excimer laser, preferably with a wavelength of 308 Nanometer, or a green light laser ( 60 ), preferably with a wavelength of 532 Nanometer, and with an optic ( 62 ) for expanding the laser beam onto a strip and means for relative movement between the laser unit ( 22 ) and the substrates ( 44 ), preferably for moving the substrates ( 44 ) relative to the laser unit ( 22 ). Plant according to one of the preceding claims, in which between some of the process chambers ( 12 . 14 . 16 . 18 . 20 . 24 . 28 . 30 . 14a ), preferably between all process chambers, separation means for separating, in particular closable bulkheads ( 26 ) are provided. Plant according to one of the preceding claims, in which the coating chamber has a heating device ( 14 ) for preheating the substrates ( 44 ) to a temperature of about 150 to 220 ° C, preferably to about 180 to 210 ° C, more preferably to about 200 ° C for coating. Plant according to one of the preceding claims, in which an infeed chamber ( 12 ) for introducing substrates ( 44 ), the coating chamber ( 14 . 30 . 14a ) the process chamber for the thermal desorption of hydrogen, the laser chamber ( 20 ) and a reject chamber ( 24 ) for discharging substrates ( 44 ) are arranged one behind the other and, as far as necessary, some process chambers are arranged in parallel to produce a uniformly cycled passage. Plant according to one of Claims 1 to 8, in which a process chamber ( 28 ) is formed as a central transfer chamber, which preferably also has heating elements, wherein the further process chambers are arranged in a star shape around the transfer chamber, and wherein preferably a common chamber ( 12 ) for introducing and removing substrates ( 44 ) is provided. Plant according to Claim 10, in which several similar process chambers ( 14 . 30 ) are provided, which can be operated in parallel with longer-lasting process steps in order to ensure uniform clocking through the entire plant ( 10 . 10a ) to ensure. Plant according to one of the preceding claims, in which the laser chamber ( 20 ) Elements ( 66 ) for preheating or cooling the substrates ( 44 ), preferably to a temperature of about 150 to 250 ° C, preferably to a temperature of about 180 to 220 ° C. Plant according to one of the preceding claims, in which the process chambers ( 12 . 14 . 16 . 18 . 20 . 24 . 28 . 30 . 14a ) are provided with a heating / cooling system, preferably with a fluid circuit, such as an oil circuit, around the process chambers ( 12 . 14 . 16 . 18 . 20 . 24 . 28 . 30 . 14a ) to a certain temperature or to cool, preferably to a temperature of 150 to 200 ° C, more preferably to a temperature of about 200 ° C. Process for coating substrates with polycrystalline silicon, comprising the following steps: - introducing substrates ( 44 ) in an annex ( 10 . 10a ) with several process chambers ( 12 . 14 . 16 . 18 . 20 . 24 . 28 . 30 . 14a ), which are airtight coupled to each other, - Vacuum coating of the substrates ( 44 ) with an amorphous silicon layer in at least one ( 14 . 30 . 14a ) of the process chambers, - heating of the substrates ( 44 ) for the thermal desorption of hydrogen from the silicon layer, and - melting of the amorphous silicon layer by means of a laser ( 60 ) for conversion into a polycrystalline silicon layer. The method of claim 14, wherein the coating with an amorphous silicon layer by means of a CVD method, preferably by means of a PECVD method, under vacuum at a coating temperature of 150 to 250 ° C, preferably from 180 to 220 ° C, more preferably at about 200 ° C is performed. Process according to claim 15, in which the substrates ( 44 ) are at least partially preheated to the coating temperature prior to coating. The method of claim 15 or 16, wherein for the coating, a mixture of silane (SiH ₄ ) and a protective gas, preferably argon, preferably with a mixing ratio of about 1: 3 to 1: 6, more preferably from about 1: 5 of silane to Argon is supplied, preferably at a pressure of about 0.5 to 10 mbar, more preferably at a pressure of 1 to 5 mbar. Method according to one of claims 14 to 17, wherein for a layer thickness of about 50 nanometers, a coating time of about 0.3 to 3 minutes, preferably from about 0.5 to 1.5 minutes, more preferably about 1 minute, is maintained , Method according to claim 14, in which the amorphous silicon layer is applied by means of a sputtering method, an ALD method, an IBD method (ion beam deposition or an evaporation method (e-beam and thermal). Method according to one of Claims 14 to 19, in which the substrates ( 44 ) are heated to a temperature of about 150 to 300 ° C, preferably from about 180 to 250 ° C for the desorption of hydrogen, preferably to a temperature of about 200 to 220 ° C, and preferably about 0.5 to 5 min, on preferably kept at this temperature for about 1 to 3 minutes. Method according to one of Claims 14 to 20, in which the substrates ( 44 ) preferably in the still warm state in a laser chamber ( 20 ) and there treated by means of an excimer laser, preferably 308 nm, or a green light laser, preferably 532 nm, to convert the amorphous silicon layer into a polycrystalline silicon layer. Process according to Claim 20 or 21, in which the substrates ( 44 ) during the laser treatment at an average substrate temperature (measured on its support surface on a substrate support ( 42 )) of about 100 to 250 ° C, preferably from about 100 to 200 ° C, more preferably from about 150 to 200 ° C, are held. Process according to Claim 21 or 22, in which the substrates ( 44 ) during the laser treatment relative to a laser unit ( 22 ) are moved, which a linearly widened laser beam ( 64 ), preferably at a rate of about 0.5 to 5 cm / s, more preferably 1 to 3 cm / s, more preferably about 1 to 2 cm / s.

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