CN207993803U - Apparatus for chemically treating semiconductor substrates with surface structures formed by sawing - Google Patents

Abstract

The utility model relates to a saw-formed surface structure (S) for chemical treatment₀) The apparatus (1) for semiconductor substrates (2) comprises a first process tank (6) with a first process liquid (10). The first process liquid (10) is suitable for removing both sawn and formed from a semiconductor meltSurface structure of (S)₀) It is also suitable for producing textured surface structures (S) by metal-assisted chemical etching₁). The textured surface structure is then thoroughly cleaned (S) by means of a cleaning device (7)₁). The textured surface structure is subsequently treated in a second process tank (8) by means of a second process liquid (18) (S)₁). Post-treated textured surface structure (S)₂) The manufacture of solar cells with very low reflection losses and high efficiency is achieved.

Description

For the chemical treatment of semiconductor substrates with sawn surface structures equipment

technical field

The utility model relates to a device and method for chemically treating a semiconductor substrate with a surface structure formed by sawing or molded by semiconductor melt. The surface structure formed by sawing includes sawing damage, which is especially caused by the diamond wire sawing process.

Background technique

The efficiency of solar cells depends on reflection losses. To minimize reflection losses and optimize efficiency, semiconductor substrates are fabricated with textured surface structures. If such semiconductor substrates or silicon substrates are processed by particularly efficient methods, they are referred to, for example, as "black silicon".

A method for producing a semiconductor substrate with a textured surface structure is, for example, metal assisted chemical etching (English abbreviation: MACE, Metal Assisted Chemical Etching). Metal-assisted chemical etching is known, for example, from WO 2014/166256 A1. This has the disadvantage that, before the metal-assisted chemical etching in order to produce the textured surface structure, the semiconductor substrate must be pretreated in a complex manner in order to remove the surface structure formed by sawing or sawing damage, which was caused by the previous caused by the wire saw. This also applies correspondingly to substrates of semiconductors which are produced directly from a semiconductor melt by means of direct-wafer technology and whose surface structure is formed from the semiconductor melt.

Utility model content

The technical problem to be solved by the utility model is to provide a device for chemically treating semiconductor substrates with surface structures formed by sawing or formed by semiconductor melts, which can be carried out in a simple and effective manner. The method removes surface structures formed by sawing or is formed from semiconductor melts and produces textured surface structures for the production of solar cells with extremely low reflection losses and high efficiencies. In particular, the device makes it possible in a simple and efficient manner to remove surface structures produced by diamond wire saws or formed by semiconductor melts and to generate effective textured or effectively textured surface structures.

Above-mentioned technical problem is solved by the equipment according to the utility model, promptly a kind of equipment for the chemical treatment of the semiconductor substrate that has the surface structure that is formed by sawing, it comprises: have the first process bath of the first process liquid, The first process liquid is used for removing surface structures formed by sawing and for producing a textured surface structure by metal-assisted chemical etching, for performing at least one cleaning of the textured surface structure Apparatus with a second process tank with a second process liquid for post-processing the cleaned textured surface structure by chemical etching. According to the present invention, if the first process tank contains the first process liquid, the first process liquid is not only suitable for removing the surface structure formed by sawing or formed by semiconductor melt, but also suitable for removing the surface structure formed by metal-assisted chemical etching or Saying that wet chemical etching produces a textured surface structure, it is simpler and more efficient to achieve a textured surface structure with lower reflection loss and high efficiency. Thus, saw damage or surface structures formed by sawing or formed from the semiconductor melt are removed by the first process liquid, and a textured surface structure is produced by metal-assisted chemical etching. In particular, this takes place only in the first process tank or only with the first process liquid, ie in a single process tank or process step. In particular, surface structures formed by sawing or surface structures damaged by sawing that result from the diamond wire saw process (English: DWS, Diamant Wire Saw) are removed by means of the first process liquid. The metal ions contained in the first process liquid create pores in the nanometer range on the surface of the semiconductor substrate to constitute a textured surface structure. The pores preferably have a diameter between 50 nm and 500 nm. The textured surface structure is then effectively and reliably removed of metal ions by means of a cleaning device, so that on the one hand the metal-assisted chemical etching is terminated and the metal-assisted texturing is no longer carried out, and on the other hand, damage caused by remaining metal ions is avoided. Reduced efficiency. The subsequent post-treatment with the second process liquid in the second process tank serves to reduce the surface of the cleaned textured surface structure and to produce an optimized surface structure. The post-processing is carried out by chemical or wet-chemical etching, but this post-processing is not metal-assisted. The second process liquid may be alkaline or acidic. The second process liquid is preferably acidic. The second process liquid may contain additives. The second process liquid is especially free of hydrogen peroxide. The apparatus is preferably used for the chemical treatment of polycrystalline semiconductor substrates. Semiconductor substrates are especially silicon substrates.

The terms "first" process tank and "second" process tank are only used to distinguish process tanks, and are not interpreted as limiting. In particular, further tanks, for example process tanks, cleaning tanks and/or rinsing tanks, can be arranged before, between and/or after the process tanks. Correspondingly, the terms "first" process liquid and "second" process liquid are only used to distinguish process liquids, and are not to be construed as limiting.

The apparatus preferably has at least one transport device for transporting the semiconductor substrates in the transport direction. The at least one conveying device extends at least from the first process tank to the cleaning device, preferably at least from the first process tank to the second process tank, and in particular extends from the first process tank until it is arranged in the Cleaning device after the second process tank. The at least one transport device can enable discontinuous or continuous horizontal transport of the semiconductor substrates along the transport direction. In a first embodiment, the plant has a transport device that transports the semiconductor substrates discontinuously or continuously and horizontally from the first process tank to a cleaning device arranged downstream of the second process tank . In a second embodiment, the apparatus has two conveyors, wherein the first conveyor transports the semiconductor substrate discontinuously or continuously and horizontally from the first process tank until it is arranged in the first The cleaning device after the process tank, and the second conveying device transports the semiconductor substrate discontinuously or continuously and horizontally from the second process tank at least as far as the cleaning device arranged after the second process tank. Between the transport devices, the semiconductor substrates are transported, for example manually or by means of handling devices.

The device according to an improved embodiment ensures simple and effective removal of sawn-formed or shaped surface structures from the semiconductor melt and generation of textured surface structures. That is, the first process liquid contains hydrogen fluoride, nitric acid and metal ions, especially silver ions. The first process liquid is especially an aqueous solution comprising hydrogen fluoride, nitric acid and metal ions, especially silver ions. The aqueous solution has in particular distilled water as a base. Silver ions are preferably contained in the first process liquid in the form of hydrated silver ions, wherein the silver is preferably added to the aqueous solution in the form of silver nitrate. The metal ions act as catalysts in the first process liquid and locally accelerate wet chemical etching. In this way, etch pits or etch holes are formed on the surface of the semiconductor substrate in the region of the metal ions or metal particles present. The sum of the etch pits forms the textured surface structure of the semiconductor substrate.

The device according to an improved design ensures the removal of surface structures formed by sawing or formed from the semiconductor melt and the production of textured surface structures in a simple and efficient manner. The first process liquid contains 3% to 21% hydrogen fluoride, 12% to 20% nitric acid and 0.001% to 0.05% silver nitrate. The first process liquid is especially an aqueous solution with hydrogen fluoride, hydrohydrate and silver nitrate. The aqueous solution preferably has distilled water as a base. Preferably, the first process liquid comprises 12% to 20% of hydrogen fluoride HF, 15% to 20% of nitrate HNO ₃ and 0.001% to 0.015% of silver nitrate AgNO ₃ , especially 15% of hydrogen fluoride HF, 20% of HNO ₃ nitrate and 0.005% silver nitrate AgNO ₃ . The above data are percentages by mass.

The device according to an improved embodiment ensures simple and effective removal of sawn-formed or shaped surface structures from the semiconductor melt and generation of textured surface structures. The first process liquid comprises less than 5%, especially less than 1%, and especially 0% hydrogen peroxide. Hydrogen peroxide affects the desired metal assisted chemical etch. The first process liquid is preferably free of hydrogen peroxide. This optimizes the process duration and process stability and simplifies the construction of the plant since, for example, less process chemicals are required for the operation of the plant. The data are percent by mass.

The device according to an improved embodiment ensures simple and effective removal of sawn-formed or shaped surface structures from the semiconductor melt and generation of textured surface structures. The first process liquid has a temperature T ₁ , wherein: 10°C≦T ₁ ≦45°C, especially 20°C≦T ₁ ≦35°C. The desired metal-assisted chemical etching and the process time are optimized by means of the temperature T ₁ .

The device according to an improved design ensures high efficiency. The cleaning device has at least one cleaning tank with a cleaning liquid containing nitric acid, especially 5% to 68% nitric acid, and especially 5% to 67% nitric acid, wherein the cleaning liquid has in particular a temperature T _R , for which it is stipulated: 15°C ≤ T _R ≤ 65°C, especially 40°C ≤ T _R ≤ 50°C. The at least one cleaning tank is arranged behind the first process tank. Efficient removal of metal ions from the textured surface structure by a cleaning liquid containing nitric acid. In particular, metal ions located in the etch pits or the textured surface structure are also removed by the cleaning liquid. A reduction in the efficiency of solar cells made of the semiconductor substrate due to retained metal ions is effectively avoided through reliable and effective cleaning. Preferably, the cleaning liquid is an aqueous solution comprising nitric acid. The aqueous solution preferably has distilled water as a base. The cleaning liquid contains especially 20% to 45% nitric acid. The data are percent by mass. The cleaning is optimized and the process time is reduced by means of the temperature T _R . The cleaning liquid is preferably free of hydrogen peroxide. The cleaning liquid initially has no metal ions. The at least one cleaning tank is designed as a immersion tank and/or a spray tank. In the case of a configuration as a immersion bath, the cleaning of the textured surface structure takes place by immersing the semiconductor substrate in the cleaning liquid. In the case of a configuration as a spray trough, the textured surface structure is cleaned by spraying with a cleaning liquid and then receiving the cleaning liquid in the spray trough. If the at least one cleaning tank is configured as a spray tank, preferably at least one spray unit for spraying cleaning liquid is arranged in and/or above the at least one cleaning tank. If the at least one cleaning tank is designed as a immersion tank, the cleaning device has, for example, at least one ultrasonic unit in order to be able to generate ultrasonic waves in the cleaning liquid.

The device according to an improved design ensures high efficiency. The cleaning device has a plurality of successively arranged cleaning tanks with cleaning liquid. Metal ions are removed very thoroughly by the step-by-step cleaning of the textured surface structure in or by means of several successively arranged cleaning baths. In each subsequent cleaning bath, the concentration of metal ions cleaned off in the cleaning liquid is lower, thus reducing the possibility of recontamination of the textured surface structure. Multiple cleaning tanks form cascade cleaning. For this purpose, the last cleaning bath in the transport direction of the semiconductor substrates preferably uses unused or clean cleaning liquid which is reused after the cleaning process for the preceding cleaning baths in the transport direction. After being used again, the cleaning liquid is preferably used again in the preceding cleaning tank in the conveying direction. This process is repeated until the cleaning liquid that has been used multiple times is supplied to the treatment station or regenerated after the cleaning process by means of the first cleaning tank (viewed in the conveying direction). In particular two and preferably three cleaning tanks are arranged one behind the other. The at least one cleaning tank is designed as a immersion tank and/or a spray tank. In the case of a configuration as a immersion bath, the cleaning of the textured surface structure takes place by immersing the semiconductor substrate in the cleaning liquid. In the case of a configuration as a shower trough, the textured surface structure is cleaned by spraying with cleaning liquid and then receiving the cleaning liquid in the spray trough. In the case of a configuration as a shower trough, the textured surface structure is cleaned by spraying with cleaning liquid and then receiving the cleaning liquid in the spray trough. If the at least one cleaning tank is configured as a spray tank, preferably at least one spray unit for spraying cleaning liquid is arranged in and/or above the at least one cleaning tank. If the at least one cleaning tank is designed as a immersion tank, the cleaning device has, for example, at least one ultrasonic unit in order to be able to generate ultrasonic waves in the cleaning liquid. The cleaning liquid especially contains nitric acid. Preferably, the cleaning liquid is an aqueous solution of distilled water and nitric acid. The cleaning liquid preferably has a temperature T _R , wherein 15°C ≤ T _R ≤ 65°C, especially 20°C ≤ T _R ≤ 45°C, and especially 40°C ≤ T _R ≤ 50°C.

The device according to an improved design ensures high efficiency. The cleaning device has at least one spray unit for spraying cleaning liquid onto the textured surface structure, the spray unit being arranged in particular in and/or above at least one cleaning tank . The at least one spray unit has at least one nozzle. The at least one spray unit preferably has a plurality of nozzles which are arranged in such a way that the bottom and/or top side of the semiconductor substrate is sprayed with cleaning liquid. The at least one spraying unit is preferably arranged in such a way that the cleaning liquid takes over in the at least one cleaning tank after spraying the semiconductor substrate. The at least one cleaning tank is thus designed as a spray tank.

The device according to an improved design ensures high efficiency. The cleaning device has a plurality of spray units arranged one behind the other for spraying cleaning liquid onto the textured surface structure, the spray units being arranged in particular in each case inside a corresponding cleaning tank and/or above. The shower units are arranged one after the other along the transport direction of the semiconductor substrate. Each spray unit has at least one nozzle. Each spray unit preferably has a plurality of nozzles, which spray the bottom and/or top side of the semiconductor substrate with cleaning liquid. A cleaning tank is associated or assigned to each spray unit. The cleaning tank is arranged relative to the associated spraying unit in such a way that the cleaning liquid takes over in the cleaning tank after spraying the semiconductor substrate. The cleaning tank is thus designed as a spray tank. Preferably, apart from the first shower unit in the transport direction of the semiconductor substrate, the shower unit has an overflow opening relative to the shower unit arranged ahead in the transport direction. The cleaning liquid in the last cleaning tank is taken up after the cleaning process by means of the last spray unit in the conveying direction and is thus used for the re-cleaning process by means of the preceding spray unit. After the re-cleaning process, the cleaning liquid is conducted again via the overflow opening to the upstreamly arranged spray unit. This is repeated up to the first spray unit, wherein the cleaning liquid taken up in the first cleaning tank is then supplied to the treatment station or regenerated. Efficient and resource-saving cleaning is achieved by the described cascading cleaning and the re-use of cleaning liquid in each cleaning process which contains fewer metal ions than in the preceding cleaning process.

The device according to an improved design ensures high efficiency. The cleaning device has at least one rinsing tank with a rinsing liquid, wherein the rinsing liquid is selected in particular from liquids, namely water and distilled water. The at least one rinsing tank is preferably arranged directly downstream of the first process tank. Preferably, several rinsing tanks are provided, which are arranged directly downstream of the first process tank and directly downstream of the last cleaning tank. At least one rinsing tank is configured as a dipping tank and/or a spray tank. In the case of a configuration as a shower tank, at least one spray unit for spraying the semiconductor substrate with rinsing liquid is assigned to the at least one shower tank, so that the rinsing liquid is received in the at least one rinsing tank after the rinsing process. The plurality of rinsing tanks is preferably configured as a cascaded rinsing. For this purpose, the last rinsing tank in the direction of transport of the semiconductor substrates preferably uses unused or clean rinsing liquid, for example ultrapure water, which is reused after the cleaning process for the first rinsing tank in the direction of transport. rinse tank. The rinsing liquid is preferably reused in the preceding rinsing tank in the conveying direction until the rinsing liquid is treated or regenerated after the cleaning process in the first rinsing tank viewed in the conveying direction. At least one cleaning tank can be arranged between the rinsing tanks of the rinsing cascade, preferably a plurality of cleaning tanks are arranged between the rinsing tanks of the rinsing cascade, the plurality of cleaning tanks forming the cleaning cascade.

The device according to an improved design ensures high efficiency. The cleaning device has at least one rinsing tank with rinsing liquid and at least one cleaning tank with cleaning liquid. In particular, the at least one rinsing tank is arranged directly after the first process tank and/or directly after the at least one cleaning tank. The rinsing liquid is preferably water, especially distilled water. A plurality of cleaning tanks are preferably arranged one behind the other. The cleaning liquid is especially an aqueous solution comprising nitric acid. The flushing tank is preferably arranged directly after the last cleaning tank. The at least one rinsing tank and/or the at least one cleaning tank are designed as immersion tanks and/or spray tanks. A spray unit for spraying the semiconductor substrate with a rinsing liquid or cleaning liquid is associated with each spray bath.

The device according to an improved design ensures simple and efficient post-processing of the cleaned textured surface structures. The second process liquid comprises hydrogen fluoride and nitric acid, especially 0.1% to 49% hydrogen fluoride and 2% to 65% nitric acid. A high efficiency is achieved by leveling the textured surface structure and reducing its surface by the second process liquid. The second process liquid is especially an aqueous solution comprising hydrogen fluoride and nitric acid. The aqueous solution preferably has distilled water as a base. The second process liquid is preferably free of hydrogen peroxide. This optimizes the process duration and process stability and simplifies the construction of the plant. The second process liquid contains especially 5% to 25% hydrogen fluoride HF and 15% to 30% nitric acid _HNO3 . The above data are expressed in mass percent.

The device according to an improved design ensures simple and efficient post-processing of the cleaned textured surface structures. The second process liquid has a temperature T ₂ , wherein it is stipulated that 15°C≦T ₂ ≦65°C, in particular 20°C≦T ₂ ≦35°C. The aftertreatment is optimized and process times are reduced by means of the temperature T ₂ .

The device according to an improved design ensures the production of textured surface structures with very low reflection losses and high efficiency. Equipped with a cleaning device for cleaning post-treated textured surface structures, said cleaning device having, in particular, a cleaning tank with an alkaline cleaning liquid comprising, in particular, potassium hydroxide and/or sodium hydroxide. During the post-treatment with the second process liquid, a porous or spongy surface layer results. The removal of the porous surface layer is ensured by further cleaning devices arranged downstream of the second process tank. For this purpose, the cleaning device has, in particular, a cleaning tank with an alkaline cleaning liquid. The alkaline cleaning liquid is in particular an aqueous solution comprising potassium hydroxide and/or sodium hydroxide. The aqueous solution has in particular distilled water as a base. The alkaline cleaning liquid has a temperature T _A , wherein preferably: 18°C≦ _TA ≦45°C. A rinsing tank with rinsing liquid is preferably arranged downstream of the cleaning tank. Rinsing tanks with rinsing liquid are preferably arranged upstream and downstream of the cleaning tank. The further cleaning device arranged downstream of the second process tank includes in particular at least one cleaning tank and/or at least one rinsing tank. The at least one cleaning tank and/or the at least one rinsing tank are designed as immersion tanks and/or spray tanks. A spray unit for spraying the post-treated textured surface structure with a cleaning or rinsing liquid is assigned to the spray tanks. A plurality of cleaning tanks is preferably configured as a cleaning cascade. A plurality of rinsing tanks preferably form a rinsing cascade.

The device according to an improved design ensures simple and efficient production of the textured surface structure. A transport device is provided for transporting the semiconductor substrates in the transport direction. The conveying device can realize the plant as an inline plant. The transport device ensures a discontinuous or continuous horizontal transport of the semiconductor substrates along the transport direction to the first process tank, the cleaning device, the second process tank and optionally further cleaning devices. The semiconductor substrates are preferably transported continuously and/or horizontally in the transport direction.

The technical problem to be solved by the utility model is also to provide a method for chemically treating a semiconductor substrate with a surface structure formed by sawing or formed by a semiconductor melt, the method can be simple and effective The method removes the surface structure formed by sawing or formed by the semiconductor melt and produces a textured surface structure for the production of solar cells with extremely low reflection loss and high efficiency. In particular, the method makes it possible to remove surface structures produced by diamond wire saws in a simple and efficient manner.

The above-mentioned technical problem is solved by the method that has according to the method step of the present utility model, promptly a kind of method for the chemical treatment of the semiconductor substrate that has the surface structure that is formed by sawing, it comprises method step:

- preparation of a semiconductor substrate with a surface structure formed by sawing,

- removing the surface structure formed by sawing by means of the first process liquid and producing a textured surface structure by metal-assisted chemical etching,

- performing at least one cleaning of the textured surface structure,

Post-treatment of the cleaned textured surface structure by means of a second process liquid by chemical etching. The advantages of the method according to the invention correspond to the above-mentioned advantages of the device according to the invention. In particular, the method according to the invention can also be improved by at least one feature of the device according to the invention.

A textured surface structure with very low reflection losses is ensured by means of an improved design. The textured surface structure is formed by first structure elements, wherein at least 70% of the first structure elements have a maximum dimension between 100 nm and 500 nm, in particular between 150 nm and 300 nm. Preferably at least 80%, in particular at least 90%, of the first structural elements have the largest dimension. The largest dimension is in particular the largest width parallel to the substrate plane and/or the largest length perpendicular to the substrate plane. The first structural element is produced by metal-assisted chemical etching with the aid of a first process liquid.

High efficiency is ensured by means of an improved design solution. The at least one cleaning is carried out with a cleaning liquid which contains nitric acid, in particular 5% to 68% nitric acid, and especially 5% to 67% nitric acid. By means of the at least one cleaning, the metal ions located on the textured surface structure are removed reliably and effectively, so that the metal ions do not further modify the surface structure on the one hand and on the other hand do not impair the performance of the solar cell produced from the semiconductor substrate efficiency. The textured surface structure is preferably cleaned several times successively with cleaning liquids. The cleaning liquid contains in particular 20% to 45% nitric acid HNO ₃ . The data are percent by mass. This avoids recontamination of the textured surface structure with already cleaned metal ions. The at least one cleaning is performed by immersion bathing of the semiconductor substrate and/or by spraying the semiconductor substrate. The semiconductor substrate to be cleaned is preferably sprayed with cleaning liquid several times successively on the bottom side and/or on the top side. The cleaning liquid used for the last spraying process is reused after this spraying process for the preceding spraying process arranged in the transport direction of the semiconductor substrate. Accordingly, after being reused, the cleaning liquid is used again in the preceding spraying process arranged in the conveying direction. After the first spraying process, viewed in the conveying direction, the cleaning liquid is treated or regenerated. In this way the cleaning liquid is used several times for cleaning. This is possible because the semiconductor substrate in each spraying process is not as clean as the cleaning liquid used and the cleaning liquid contains fewer metal ions than the semiconductor substrate to be cleaned. Through the cascade cleaning process, the semiconductor substrate is cleaned efficiently and resource-savingly.

High efficiency is ensured by means of an improved design solution. The at least one cleaning is carried out with a rinsing liquid, wherein the rinsing liquid is selected in particular from liquids, namely water and distilled water. The semiconductor substrate is preferably cleaned with the aid of a rinsing liquid directly after metal-assisted chemical etching. Furthermore, the semiconductor substrate is preferably cleaned with the rinsing liquid directly after the final cleaning with the cleaning liquid. Cleaning with the rinsing liquid takes place by dipping and/or spraying. Preferably, a flushing cascade is formed with the flushing liquid, the flushing liquid being used several times. In this case, the rinsing liquid is reused in the previous cleaning process, viewed in the conveying direction.

A textured surface structure with very low reflection losses is ensured by means of an improved design. The post-treated textured surface structure is formed by the second structure elements, wherein at least 70% of the second structure elements have a maximum dimension between 200 nm and 1200 nm, in particular between 200 nm and 650 nm. Preferably at least 80%, in particular at least 90%, of the second structural elements have the largest dimension. The largest dimension is in particular the largest width parallel to the substrate plane and/or the largest length perpendicular to the substrate plane. The second structural element is flattened relative to the first structural element due to the post-treatment, so that the post-treated textured surface structure has a comparatively smaller surface area.

A textured surface structure with very low reflection losses is ensured by means of an improved design. Cleaning the post-treated textured surface structure at least once, wherein the post-treated textured surface structure is cleaned in particular by means of an alkaline cleaning liquid comprising potassium hydroxide and/or or sodium hydroxide. When post-processing the textured surface structure, a porous or spongy surface layer results. The porous surface layer is removed by at least one further cleaning after the aftertreatment. The alkaline cleaning liquid is in particular an aqueous solution comprising potassium hydroxide and/or sodium hydroxide. The aqueous solution preferably has distilled water as a base. The alkaline cleaning liquid has a temperature T _A , wherein preferably: 18°C≦ _TA ≦45°C. A further cleaning with a rinsing liquid preferably follows the cleaning with a cleaning liquid. The at least one cleaning is performed by dipping and/or spraying.

The method according to an improved design ensures simple and effective removal of sawn-formed surface structures and production of textured surface structures. The method steps are carried out in a chain system and the semiconductor substrates are transported in particular continuously. By having the method steps carried out in a chain system, the semiconductor substrates are automatically transported to the method steps. Preferably, the semiconductor substrates are transported continuously and/or horizontally through the chain device. In this way, a large number of semiconductor substrates having a desired textured surface structure can be produced in a simple and efficient manner.

The invention also relates to a cleaning device for at least one cleaning of a chemically treated semiconductor substrate and to a method for at least one cleaning of a chemically treated semiconductor substrate. The cleaning device and the method are used in particular for carrying out at least one cleaning of a textured surface structure of a semiconductor substrate. The features of the cleaning device and the method for carrying out at least one cleaning are independent of other features of the device and the method for chemically treating semiconductor substrates.

Description of drawings

Other characteristics, advantages and details of the present invention are obtained from the description of several embodiments below. In the attached picture:

1 shows a schematic diagram of a chain plant according to a first exemplary embodiment for chemically processing semiconductor substrates with sawn-formed surface structures,

2 shows a top view of a semiconductor substrate with a surface structure formed by sawing and a semiconductor substrate with a textured surface structure chemically treated by means of the apparatus according to FIG. 1 ,

3 shows an enlarged top view of a semiconductor substrate after metal-assisted chemical etching by means of a first process liquid,

FIG. 4 shows an enlarged plan view of the semiconductor substrate in FIG. 3 after cleaning with a cleaning liquid,

5 shows an enlarged plan view of the textured surface structure of the semiconductor substrate in FIG. 2 after post-treatment with a second process liquid,

Figure 6 shows a graph of the reflectivity of the semiconductor substrate in Figure 5 in relation to the wavelength of light incident vertically,

7 shows a schematic diagram of a chain plant according to a second exemplary embodiment for chemically processing semiconductor substrates with surface structures formed by sawing,

FIG. 8 shows a schematic diagram of a device according to a third exemplary embodiment for chemically treating a semiconductor substrate with a surface structure formed by sawing.

Detailed ways

The first embodiment of the present utility model is described below according to FIG. 1 to FIG. 6 . The chain plant 1 for the wet-chemical treatment of semiconductor substrates 2 has a transport device 4 for transporting the semiconductor substrates 2 in the transport direction 3 . The conveying device 4 comprises a plurality of rotationally driven conveying rollers 5 arranged one behind the other in the conveying direction 3 .

The chain system 1 has a first process tank 6 , a first cleaning device 7 , a second process tank 8 and a second cleaning device 9 successively in the conveying direction 3 .

The first process bath 6 is used for removing the sawn surface structure S ₀ of the semiconductor substrate 2 and for producing the textured surface structure S ₁ by metal-assisted chemical etching. The first process tank 6 is filled with a first process liquid 10 . The first process liquid 10 is an aqueous solution based on distilled water and contains hydrogen fluoride HF, nitrate HNO ₃ and metal ions 11 , especially silver ions. The first process liquid 10 preferably comprises 3% to 21% of hydrogen fluoride HF, 12% to 20% of nitrate HNO ₃ and 0.001% to 0.05% of silver nitrate AgNO ₃ , especially 12% to 20% of hydrogen fluoride HF, 15% to ₂₀ % _HNO3 nitrate and 0.001% to 0.015% silver nitrate AgNO3. The first process liquid 10 contains, for example, 15% hydrogen fluoride HF, 20% nitrate HNO ₃ and 0.005% silver nitrate AgNO ₃ . The first process liquid 10 does not contain hydrogen peroxide H ₂ O ₂ . The first process liquid 10 has a temperature T ₁ , wherein: 10°C≦T ₁ ≦45°C, in particular 20°C≦T ₁ ≦35°C. The above data are percentages by mass.

The first cleaning device 7 serves to clean the textured surface structure S ₁ by removing metal ions 11 or metal nanoparticles. The first cleaning device 7 successively includes a first rinsing tank 12 , a first cleaning tank 13 , a second cleaning tank 14 and a second rinsing tank 15 in the conveying direction 3 . The rinsing tanks 12 , 15 are filled with rinsing liquid 16 . The rinsing liquid 16 is water, in particular distilled water. The cleaning tanks 13 , 14 are filled with cleaning liquid 17 . The cleaning liquid 17 is an aqueous solution based on distilled water, which contains 5% to 68%, especially 5% to 67%, especially 10% to 60%, and especially 20% to 45% nitric acid _HNO3 . The above data are percentages by mass. The cleaning liquid 17 has a temperature T _R , where: 15°C ≤ T _R ≤ 65°C, in particular 40°C ≤ T _R ≤ 50°C.

The second process tank 8 , which is arranged downstream of the first cleaning device 7 , is used for aftertreatment of the cleaned textured surface structure S ₁ by chemical etching. The second process tank 8 is filled with a second process liquid 18 . The second process liquid 18 is an aqueous solution based on distilled water, containing hydrogen fluoride HF and nitric acid HNO ₃ . The second process liquid 18 preferably comprises 0.1% to 49% hydrogen fluoride HF and 2% to 65% nitric acid HNO ₃ , and especially 5% to 25% hydrogen fluoride HF and 15% to 30% nitric acid HNO ₃ . The second process liquid 18 does not contain hydrogen peroxide H ₂ O ₂ . The second process liquid 18 has a temperature T ₂ , where: 15°C≦T ₂ ≦65°C, in particular 20°C≦T ₂ ≦35°C. The second process liquid 18 is used to produce a post-treated textured surface structure S ₂ which is flattened and has a smaller surface compared to the textured surface structure S ₁ .

A second cleaning device 9 arranged downstream of the second process tank 8 serves to clean the post-treated textured surface structure S ₂ . The second cleaning device 9 successively includes a rinsing tank 19 and a cleaning tank 20 in the conveying direction 3 . The rinsing tank 19 is filled with rinsing liquid 16 . The cleaning tank 20 is filled with an alkaline cleaning liquid 21 . The alkaline cleaning liquid 21 is an aqueous solution based on distilled water, which contains potassium hydroxide KOH and/or sodium hydroxide NaOH. The alkaline cleaning liquid 21 has a temperature T _A , wherein: 18°C≦ _TA ≦45°C. The alkaline cleaning liquid 21 is used in particular to remove any porous or spongy surface layers of the surface structure S ₂ that may have occurred.

According to requirements, the second cleaning device 9 can have a further rinsing tank with rinsing liquid, which is arranged downstream of the cleaning tank 20 . The second cleaning device 9 can contain further cleaning tanks, in particular after the rinsing tank. After the second cleaning device 9 or other cleaning and/or rinsing tanks, a drying device can be arranged in the usual manner.

The mode of operation of the chain plant 1 and the method for the wet-chemical treatment of a semiconductor substrate 2 with a sawn surface structure _S0 are explained below:

The semiconductor substrates 2 are transported continuously and horizontally through the chain system 1 by means of a conveyor device 4 . In particular, the semiconductor substrates 2 are transported in multiple rows in the conveyor device 3 so that a plurality of semiconductor substrates 2 can be processed or cleaned simultaneously. The semiconductor substrate 2 is, for example, a silicon substrate or a silicon wafer. The semiconductor substrate 2 is in particular polycrystalline. The surface structure _S0 formed by sawing is, for example, caused by the previous diamond wire sawing process. The surface structure _S0 formed by sawing includes sawing damage caused by the diamond wire sawing process. The semiconductor substrate 2 is conveyed by means of the conveying device 4 into the first process tank 6 as follows, that the semiconductor substrate is completely at least temporarily in the first process liquid 10 . The semiconductor substrate 2 is thus wet-chemically treated both on the bottom side 2 a and on the top side 2 b by means of the first process liquid 10 . The bottom side 2 a forms the front side in the subsequent solar cell, while the top side 2 b forms the rear side.

The semiconductor substrate 2 conveyed into the first process tank 6 has a sawn-formed surface structure S ₀ on the bottom side 2 a and the top side 2 b. The sawing-formed surface structure S ₀ or sawing damage is removed in a single process step with the aid of the first process liquid 10 and a textured surface structure S is produced by metal-assisted chemical etching (MACE: Metal Assisted Chemical Etching). ₁ . The textured surface structure S1 is produced by the precipitation of metal ions ₁₁ or silver ions on the substrate surface in the form of clusters and/or precipitates and thus acts as a catalyst and accelerates the wetting locally around it. chemical etching. In this way, first structural elements in the form of etching pits or etching holes are produced on the surface of the semiconductor substrate 2 . Etching pits are produced where metal ions 11 or metal nanoparticles are present in the form of clusters and/or precipitates. The sum of the etch pits constitutes the textured surface structure S ₁ . At least 70%, in particular at least 80%, and in particular at least 90% of the first structural elements 22 have a maximum dimension A ₁ between 100 nm and 500 nm, in particular between 150 nm and 300 nm, said maximum dimension A ₁ being in particular is the maximum width parallel to the substrate plane of the respective semiconductor substrate 2 and/or the maximum length perpendicular to the substrate plane. FIG. 2 shows a semiconductor substrate 2 with a sawn surface structure _S0 , while FIG. 3 shows _a semiconductor substrate with a textured surface structure S1 after metal-assisted chemical etching. Bottom 2. The textured surface structure S ₁ in FIG. 3 is contaminated with metal ions 11 or silver ions in the form of clusters and/or precipitates.

After the first process bath 6 , the semiconductor substrate 2 is guided to a first cleaning device 7 . The semiconductor substrate 2 is transported through the first rinsing tank 12 , the first cleaning tank 13 , the second cleaning tank 14 and the second rinsing tank 15 as follows, that is, the semiconductor substrate 2 is at least temporarily completely exposed to the rinsing liquid 16 or In the cleaning liquid 17, each bottom side 2a and each top side 2b of the semiconductor substrate 2 are cleaned. In the first rinsing tank 12 first the first process liquid 10 is removed from the semiconductor substrate 2 . In the first cleaning bath 13 and in the following second cleaning bath 14 , metal ions 11 or silver ions or metal nanoparticles are removed from or from the textured surface structure S ₁ . Metal ions 11 or silver ions or metal nanoparticles are removed in particular by highly concentrated nitric acid HNO ₃ in cleaning liquid 17 , wherein in particular metal ions 11 are also removed from first structural element 22 or from the etch pits. By arranging the two cleaning baths 13 , 14 one behind the other, the possibility of re-contamination of the textured surface structure S ₁ by metal ions 11 or silver ions that have been removed is reduced. According to requirements, further cleaning tanks can be arranged after the second cleaning tank 14 . Cleaning liquid 17 is removed in second rinsing tank 15 by means of rinsing liquid 16 . FIG. 4 shows the semiconductor substrate 2 with the cleaned, textured surface structure after the first cleaning device 7 .

After the first cleaning device 7 , the semiconductor substrate 2 is guided into a second process bath 8 . The semiconductor substrate 2 is conveyed in the conveying direction 3 by means of the conveying device 4 such that the semiconductor substrate is completely at least temporarily in the second process liquid 18 . The textured surface structure S1 is post _- treated by chemical etching with the aid of the second process liquid 18, so that the textured surface structure S1 is leveled and produces _a post-processing with a comparatively smaller surface. Treated Textured Surface Structure S ₂ . The textured surface structure S ₂ is formed by second structural elements 23 in the form of etched pits or holes. At least 70%, in particular at least 80%, and in particular at least 90% of the second structural elements 23 have a maximum dimension A ₂ between 200 nm and 1200 nm, in particular between 200 nm and 650 nm, said maximum dimension A ₂ being in particular is the greatest width parallel to the substrate plane and/or the greatest length perpendicular to the substrate plane. The post-treated textured surface structure S ₂ is shown in FIG. 5 .

After the second process bath 8 , the semiconductor substrate 2 is guided to a second cleaning device 9 . The semiconductor substrate 2 is transported in the transport direction 3 by means of the transport device 4 such that the semiconductor substrate is at least temporarily completely immersed in the rinsing liquid 16 and the alkaline cleaning liquid 21 . Firstly, the second process liquid 18 is removed from the semiconductor substrate 2 by means of the rinsing liquid 16 . Any porous or spongy surface layers that would form on the textured surface structure S ₁ in the second process liquid 18 are then removed by means of an alkaline cleaning liquid 21 . Further cleaning and/or rinsing cycles can also follow. Depending on requirements, for example, further rinsing tanks can be arranged after the cleaning tank 20 . FIG. 2 shows a comparison between a semiconductor substrate 2 having a post-processed textured surface structure S ₂ after wet-chemical treatment and a semiconductor substrate 2 having a sawn-formed surface structure S ₀ .

FIG. 6 shows the dependence of the reflectance R on the wavelength λ of a semiconductor substrate 2 produced with a textured surface structure. The chain plant 1 according to the invention or the method according to the invention enables simple and efficient production of solar cells with a reflectance R of approximately 0.10 to 0.26 in the range of visible and infrared radiation. The chain plant 1 according to the invention or the method according to the invention thus makes it possible to generate a textured surface structure S ₂ for the production of solar cells with very low reflection losses and high efficiency.

The chain arrangement according to the invention and the method according to the invention have reduced complexity and enable the production of solar cells with improved efficacy. The solar cell has, inter alia, lower reflectivity, higher efficiency, higher short-circuit current and higher open circuit voltage. _The high efficiency is caused by the surface structure S2 and thorough cleaning, which avoids a decrease in efficiency. The chain device 1 according to the invention and the method according to the invention can be easily and flexibly adapted to the solar cells to be produced.

In contrast to known methods, surface structure S ₂ does not have a porous or spongy surface layer. By carrying out at least one cleaning prior to the aftertreatment with the second process liquid 18 , the metal ions 11 are removed directly after the metal-assisted chemical etching and the metal ions 11 are prevented in advance from causing further undesired chemical etching. In addition, residual metal remaining is removed by subsequent post-treatment of the cleaned textured surface structure. The etch pits expand during postprocessing. The chain device 1 has a length of in particular up to 14 m, in particular up to 13 m and in particular up to 12 m. The process duration including all cleaning and rinsing cycles is a maximum of 6 min. In particular, the chain plant 1 according to the invention or the method according to the invention does not contain hydrogen peroxide, which results in a higher process stability. The semiconductor substrate ₂ with the surface structure S2 can be used directly for diffusion. The chain plant 1 and the method preferably contain no additional additives, in particular organic additives, in order to simplify the handling of the process liquids 10 , 18 , cleaning liquids 17 , 21 and rinsing liquid 16 . The semiconductor substrate 2 can have a surface structure S ₂ which is thicker on the bottom side 2 a than on the top side 2 b. Such a semiconductor substrate 2 is suitable for the manufacture of PERC cells (emitter and passivated cells).

The second embodiment of the present utility model is described below according to FIG. 7 . The first cleaning device 7 successively comprises a first washing tank 12, a first cleaning tank 13, a second cleaning tank 14, a third cleaning tank 14' and a second washing tank 15 along the conveying direction 3. A spray unit 24 is assigned to the first rinsing tank 12 . The spray unit 24 includes a storage container 28 with rinsing liquid 16 . The rinsing liquid 16 is supplied to the first nozzle 25 and the second nozzle 25' via a spray line 26 by means of a pump 27. The first nozzle 25 sprays the bottom side 2 a of the semiconductor substrate 2 , and the second nozzle 25 ′ sprays the top side 2 b of the semiconductor substrate 2 . The rinsing liquid 16 collected in the first rinsing tank 12 is led back to the storage container 28 via the return line 26'.

The cleaning tanks 13 , 14 and 14 ′ are configured as a cleaning cascade. To this end, each of the cleaning tanks 13, 14, 14' is assigned a spray unit 29, 30, 31 respectively. The last spray unit 31 in the conveying direction 3 has a storage container 32 into which clean or prepared, ie uncontaminated, cleaning liquid 17 is conducted via a line 33 . Alternatively, the clean or ready-to-use cleaning fluid can be introduced directly through the first nozzle 37 and the second nozzle 37'. The cleaning liquid 17 is raised to a temperature _TR by means of a heater 34 . The cleaning liquid 17 is supplied to the first nozzle 37 and the second nozzle 37 ′ through the spray line 35 by means of the pump 36 . A first nozzle 37 sprays the bottom side 2 a of the semiconductor substrate 2 with the cleaning liquid 17 , and a second nozzle 37 ′ sprays the top side 2 b of the semiconductor substrate 2 with the cleaning liquid 17 . The cleaning liquid 17 collected in the third cleaning tank 14' is led back into the storage container 32 via the return line 35'.

The central spray unit 30 , which is arranged ahead in the conveying direction 3 relative to the spray unit 31 , comprises a storage container 38 which is supplied with used cleaning liquid 17 via an overflow opening 39 from the storage container 32 . The cleaning liquid 17 is kept at a temperature T _R by means of a heater 40 . Cleaning liquid 17 is supplied from storage container 38 via spray line 41 to first nozzle 43 and second nozzle 43 ′ by means of pump 42 . A first nozzle 43 sprays the bottom side 2 a of the semiconductor substrate 2 with the cleaning liquid 17 , and a second nozzle 43 ′ sprays the top side 2 b of the semiconductor substrate 2 with the cleaning liquid 17 . The cleaning liquid 17 collected in the second cleaning tank 14 is led back to the storage container 38 via the return line 41 ′.

The first douche unit 29 , which is arranged in front of the douche unit 30 in the conveying direction 3 , comprises a storage container 44 which is supplied with the used cleaning liquid 17 via an overflow opening 45 from the storage container 38 . The cleaning liquid 17 is kept at a temperature T _R by means of a heater 46 . Cleaning liquid 17 is supplied from a storage container 44 via a spray line 47 to a first nozzle 49 and a second nozzle 49 ′ by means of a pump 48 . A first nozzle 49 sprays the bottom side 2 a of the semiconductor substrate 2 with the cleaning liquid 17 , and a second nozzle 49 ′ sprays the top side 2 b of the semiconductor substrate 2 with the cleaning liquid 17 . The cleaning liquid 17 collected in the first cleaning tank 13 is led back to the storage container 44 via a return line 47 ′. A discharge line 50 leads from the storage container 44 . The discharge line 50 leads, for example, to a regeneration device, not further shown. The regeneration device removes the metal ions 11 cleaned from the semiconductor substrate 2 from the cleaning liquid 17 , and the regenerated cleaning liquid 17 is redirected to the storage container 32 through the conduit 33 . Alternatively, the conduit 33 is connected to a supply container, not further shown, and the discharge line 50 is connected to a treatment container, not further shown, so that both the supply and the treatment of the cleaning liquid 17 are ensured.

Cleaning liquid 17 has a first concentration K ₁ of metal ions 11 in storage container 44 , a second concentration K ₂ of metal ions 11 in storage container 38 and a third concentration K ₃ of metal ions 11 in storage container 32 . For the concentrations: K ₁ >K ₂ >K ₃ . In this way, cascading cleaning is realized, and the possibility of recontamination of the textured surface structure S ₁ by the removed metal ions 11 is reduced.

A spray unit 51 is assigned to the second rinsing tank 15 . The spray unit 51 includes a storage container 52 with rinsing liquid 16 . The rinsing liquid 16 is supplied from the storage container 52 via the spray line 53 by means of the pump 54 to the first nozzle 55 and the second nozzle 55'. A first nozzle 55 sprays the bottom side 2 a of the semiconductor substrate 2 with the rinsing liquid 16 , and a second nozzle 55 ′ sprays the top side 2 b of the semiconductor substrate 2 with the rinsing liquid 16 . After the rinsing process, the rinsing liquid 16 is collected in the second rinsing tank 15 and returned to the storage container 52 via the return line 53'.

The spray units 24 , 51 can be configured as a flushing cascade. This structure basically corresponds to a cleaning cascade. The douche unit 51 is operated with clean or unused rinsing liquid 16 , for example ultrapure water, which is conducted after the cleaning process for the reuse of the douche unit 24 . Furthermore, the respective last nozzles 25, 25' of the spray unit 24 in the conveying direction 3 and the last nozzles 55, 55' of the spray unit 51 supply clean water independently of the other nozzles 25, 25' and 55, 55' The rinsing liquid 16, for example ultrapure water, is supplied. An efficient and/or resource-saving cleaning with rinsing liquid 16 is thereby achieved.

In order to prevent an undesired overflow of cleaning liquid 17 from the first cleaning tank 13 and the associated spray unit 29 to the second cleaning tank 14 and the associated spray unit 30 , the spray unit 29 has a roller 5 ′, the roller 5 ′ The cleaning liquid 17 is removed from the top side 2 b of the semiconductor substrate 2 . In a corresponding manner, the spray units 30 and 31 have rollers 5 ′ which remove the cleaning liquid 17 from the top side 2 b of the semiconductor substrate 2 . The roll 5' is also called squeeze roll. Squeeze rollers can be used alone between tanks in the form of dipping tanks or spray tanks, regardless of whether the tanks are implemented as process tanks, cleaning tanks or rinsing tanks.

The second cleaning device 9 successively comprises a first rinsing tank 19 , a cleaning tank 20 and a second rinsing tank 19 ′ along the transport direction 3 . A spray unit 56 is assigned to the first rinsing tank 19 . The spray unit 56 comprises a storage container 57 filled with rinsing liquid 16 . The rinsing liquid 16 is supplied from the storage container 57 via the spray line 58 by means of the pump 59 to the first nozzle 60 and the second nozzle 60'. A first nozzle 60 sprays the bottom side 2 a of the semiconductor substrate 2 with the rinsing liquid 16 , and a second nozzle 60 ′ sprays the top side 2 b of the semiconductor substrate 2 with the rinsing liquid 16 . After the rinsing process, the rinsing liquid 16 is collected in the first rinsing tank 19 and returned to the storage container 57 via the return line 58'.

The cleaning tank 20 is designed as a dipping tank in accordance with the first exemplary embodiment. The roller 5' removes the alkaline cleaning liquid 21 from the top side 2b of the semiconductor substrate 2 and prevents the alkaline cleaning liquid 21 from entering the second rinsing tank 19' or the rinsing liquid 16 in the second rinsing tank 19' .

The second rinsing tank 19 ′ is used for cleaning the semiconductor substrate 2 again with the rinsing liquid 16 . A spray unit 69 is assigned to the second rinsing tank 19'. The spray unit 69 comprises a storage container 70 filled with rinsing liquid 16 . The rinsing liquid 16 is supplied from the storage container 70 via the spray line 71 by means of the pump 72 to the first nozzle 73 and the second nozzle 73'. A first nozzle 73 sprays the bottom side 2 a of the semiconductor substrate 2 with the rinsing liquid 16 , and a second nozzle 73 ′ sprays the top side 2 b of the semiconductor substrate 2 with the rinsing liquid 16 . After the rinsing process, the rinsing liquid 16 is collected in the second rinsing tank 19' and is introduced into the storage container 70 via the return line 71'.

The spray units 56 , 69 can be configured as a flushing cascade. This structure basically corresponds to the structure of a cleaning cascade. The douche unit 69 is operated with clean or unused rinsing fluid 16 , for example ultrapure water, which is conducted after the cleaning process for the reuse of the douche unit 56 . In addition, the respective last nozzles 60, 60' of the spray unit 56 in the conveying direction 3 and the last nozzles 73, 73' of the spray unit 69 supply clean water independently of the other nozzles 60, 60' and 73, 73'. The rinsing liquid 16, for example ultrapure water, is supplied. An efficient and/or resource-saving cleaning with rinsing liquid 16 is thereby achieved.

The spray units 24 , 51 , 56 , 69 can be configured in the same way as a flushing cascade. This configuration basically corresponds to that of a cleaning cascade. The spray unit 69 is operated with clean or unused rinsing liquid 16 , for example ultrapure water, which is passed to the spray unit 56 after the cleaning process for reuse.

Reference is made to the preceding exemplary embodiments with regard to the further configuration and further mode of operation of the chain device.

The third embodiment of the present utility model is described below according to FIG. 8 . The difference with respect to the previous exemplary embodiment is that the device 1 has a first conveying device 4 and a downstream second conveying device 4 ′. The first transport device 4 transports the semiconductor substrate 2 in the transport direction from the first process tank 6 to the second rinse tank 15 . The semiconductor substrate 2 is then guided manually or by means of a handling device not further shown to the second transport device 4', which transports the semiconductor substrate 2 along the transport direction from the second process tank 8 to the second rinsing Groove 19'. In this way, the metal-assisted chemical etching and texturing of the surface structure S by means of the _first process liquid 10 and the subsequent cleaning of the chemical etching and post-treatment of the textured surface structure S by means of the second process liquid 18 ₂ and then clean decoupling. With regard to the further construction and further modes of operation, reference is made to the preceding exemplary embodiment.

The cleaning tanks 13 , 14 , 14 ′, 20 and/or the rinsing tanks 12 , 15 , 19 , 19 ′ can be designed as immersion tanks and/or spray tanks. The features of the individual exemplary embodiments can be combined with each other as desired and in any desired way. The device 1 is also suitable for the chemical treatment of semiconductor substrates 2 produced directly from a semiconductor melt by means of the direct-wafer technique and having a surface structure S ₀ formed from the semiconductor melt.

Basically, all tanks, in particular not only the cleaning tanks 13, 14, 14' and the rinsing tanks 12, 15, 19, 19', but also the process tanks 6, 8 and the cleaning tank 20 can dispense with one of the following components Or several, in particular all, namely: a storage container, in particular with a heater, a pump, in particular for conveying process liquids or cleaning liquids, one or more supply and discharge lines and fresh medium supply lines.

For clarity, it is not shown in the drawings.

Correspondingly, the rinsing tanks 12 and 15 can also have supply and discharge lines for the medium supply.

Claims (15)

1. An apparatus for chemically treating a semiconductor substrate with a surface structure formed by sawing, comprising: - a first process tank (6) with a first process liquid (10) for removing surface structures (S ₀ ) formed by sawing and for metal-assisted chemical etching for producing a textured surface structure (S ₁ ), - a first cleaning device (7) for at least one cleaning of said textured surface structure (S ₁ ), - a second process tank (8) with a second process liquid (18) for chemically etching the cleaned textured surface structure (S ₁ ) Do postprocessing. 2. Plant according to claim 1, characterized in that the first process liquid (10) has _a temperature T1, wherein: ₁₀ °C≤T1≤45°C. 3. Plant according to claim 2, characterized in that said first process liquid (10) has _a temperature T1, wherein: 20° _C≤T1≤35 °C. 4. The device according to claim 1, characterized in that the first cleaning device (7) has at least one cleaning tank (13, 14; 13, 14, 14') with cleaning liquid (17), In this case, the cleaning liquid ( 17 ) has a temperature T _R , for which it is stipulated that 15°C≦T _R ≦65°C. 5. The device as claimed in claim 4, characterized in that the cleaning liquid (17) has a temperature T _R , for which it is stipulated that 40°C≦T _R ≦50°C. 6. The device according to claim 1, characterized in that the first cleaning device (7) has a plurality of cleaning tanks (13, 14; 13, 14, 14) arranged one behind the other with cleaning liquid (17) '). 7. The device according to claim 1, characterized in that the first cleaning device (7) has at least one spray unit (29, 30, 31) for spraying the textured surface structure (S ₁ ) Spraying cleaning liquid (17) on top, said at least one spraying unit being arranged in and/or above at least one cleaning tank (13, 14, 14'). 8. The device according to claim 1, characterized in that the first cleaning device (7) has a plurality of successively arranged spray units (29, 30, 31) for spraying the textured surface A cleaning liquid (17) is sprayed on the structure (S ₁ ), and the plurality of successively arranged spray units are respectively arranged inside and/or above the corresponding cleaning tanks (13, 14, 14'). 9. The device according to claim 1, characterized in that the first cleaning device (7) has at least one rinsing tank (12, 15) with a rinsing liquid (16), wherein the rinsing liquid ( 16) Choose from water and distilled water. 10. The device according to claim 1, characterized in that the first cleaning device (7) has at least one rinsing tank (12, 15) with rinsing liquid (16) and at least one rinsing tank (12, 15) with cleaning liquid ( 17) cleaning tanks (13, 14; 13, 14, 14'). 11. The plant according to claim 1, characterized in that the _second process liquid (18) has a temperature T2, wherein it is stipulated that ₁₅ °C≦T2≦65°C. 12. The plant according to claim 11, characterized in that the _second process liquid (18) has a temperature T2, wherein it is stipulated that ₂₀ °C≦T2≦35°C. 13. The device according to claim 1, characterized in that it is equipped with a second cleaning device ( ₉ ) for cleaning the post-treated textured surface structure (S2). 14. The device according to claim 13, characterized in that the second cleaning device (9) has a cleaning tank (20) with an alkaline cleaning liquid (21). 15. The device according to claim 1, characterized in that the device is equipped with a transport device (4; 4, 4') for transporting the semiconductor substrate (2) in the transport direction (3; 3, 3') ).