DE102018206978A1 - Method and apparatus for treating etched surfaces of a semiconductor substrate using ozone-containing medium - Google Patents

Abstract

A method of treating a surface of a textured silicon substrate comprises ozone-based treatment of the surface of the textured silicon substrate to effect removal of porous silicon and / or metal cleaning and / or cleaning of organic compounds.

Description

The present invention relates to a method and apparatus for treating a surface of a textured silicon substrate. More particularly, the present invention relates to a method of treating etched surfaces of a semiconductor substrate using ozone-containing medium, wherein such semiconductor substrates are applicable to, for example, photovoltaic modules. Exemplary embodiments relate to a method for cleaning etched surfaces of a semiconductor substrate and / or for post-cleaning of multicrystalline diamond wire-sawn silicon substrates. Treatment of a textured silicon substrate may involve cleaning thereof, which may be done using, for example, an ozone-containing medium.

Semiconductor substrates may be textured during their further processing, that is, the surface of the semiconductor substrate may be treated, such as to perform a roughening. Texturing can be obtained, for example, by means of an acidic texture in the inline process. These are for example in US 2010/0055398 A1 or EP 2 232 526 B1 described.

An apparatus and method for asymmetric alkaline texture of surfaces is disclosed in U.S. Pat DE 10 2013 218 693 A1 described.

A texture can also be obtained by an acid etching, as for example in US 2015/0040983 A1 is described.

Diamond wire sawn multicrystalline wafers can also be textured.

Texturing can also be achieved with acidic media using additive or organic compounds. For this, an etching mixture may be used to produce a textured surface on silicon substrates. Such an etching mixture may comprise at least one polymer as thickening agent. Specifically, a polymer resistant to nitric acid and hydrofluoric acid and / or a hydrophilic polymer can be used. Such a polymer used as thickener may be selected from the group consisting of cellulose, especially methyl cellulose, polyvinyl alcohol and polyethylene oxide. In CN 103132079 A Additives are described which consist of polyvinyl alcohol and polyethylene glycol alcohol.

A conventional method will be described with reference to 7 explained in more detail.

For example. from US 6,503,333 B2 known and here as 7 reproduced representation shows that ozone can be used for rinsing. Steps 32 and 36 described therein relate to the two baths of RCA cleaning, wherein after each bath, a quick dump rinse rinse comprising ozone (O ₃ ) is carried out. Also in DE 10 2010 054 370 A1 is a use of ozone for cleaning described. The alkaline etch process is combined with an additional purification step using hydrofluoric acid and ozone to provide a polished and clean surface that is used for SiO ₂ / SiN _x stack passivation. Here only a removal of detergent residues takes place.

A disadvantage of known methods is that they have a high complexity.

Accordingly, it would be desirable to have methods and apparatus for treating semiconductor substrates that are low in complexity.

The object of the present invention is therefore to provide a method for treating a surface of a textured silicon substrate and an apparatus for carrying out such a method, which have a low complexity.

This object is solved by the subject matter of the independent patent claims.

One recognition of the present invention is to have realized that by using an ozone-based treatment, removal of porous silicon and / or metal cleaning, ie, removal of metal residues, and / or purification of organic compounds or components can be obtained. so that an identical or comparable process step both cleaning steps can be carried out individually or in combination, instead of performing an alkaline or an acid post-cleaning. This allows for low complexity since the same cleaning step can be used for different purposes. The use of the ozone-based treatment makes it possible to reduce the number of chemical process steps, since at the same time the porous silicon materials as well as the metals and / or organic components can be cleaned or removed. Thus, a further reduced low complexity can be obtained by reducing the number of rinsing steps by performing the purifications, the removal of the porous silicon and / or the metal cleaning and / or the purification of organic compounds or components simultaneously. This allows the reduction of the process time and thus an increase in throughput in relation to existing systems and / or processes. Furthermore, a reduction of the chemical consumption is made possible and a smaller dimension of the sequentially operating plants, that is, shorter plants. Furthermore, advantages obtained therefrom, in particular when the low consumption of chemicals in avoiding hydrogen chloride, potassium hydroxide and / or hydrogen peroxide, lies in the low cost of operating the plant. Also, the smaller number of purification steps makes it possible to obtain lower costs. Indirectly, disposal costs can also be saved since fewer (different) wastewater types are obtained.

Examples provide a method of treating a surface of a textured silicon substrate. The method comprises ozone-treating the surface of the textured silicon substrate to effect removal of porous silicon and / or metal cleaning and / or organic compound purification.

Examples provide an apparatus for carrying out such a method. Such apparatus includes process media supply means for providing an ozone-based treating medium and substrate handling means for positioning the silicon substrate to treat the surface.

• 1a ein schematisches Ablaufdiagramm eines Verfahrens gemäß dem Stand der Technik;
• 1b ein schematisches Ablaufdiagramm eines Verfahrens gemäß einem Ausführungsbeispiel;
• 2 ein schematisches Ablaufdiagramm eines Verfahrens gemäß einem Ausführungsbeispiel, das einen optionalen Schritt des Abreinigens von organischen Verbindungen aufweist;
• 3 ein schematisches Ablaufdiagramm eines Verfahrens gemäß einem Ausführungsbeispiel, das einen Schritt umfasst, bei dem mittels der ozonbasierten Behandlung gleichzeitig die Abreinigung, die Entfernung des porösen Siliziums und die Metallreinigung erfolgt;
• 4 eine schematische Darstellung einer zum Durchführen eines Verfahrens gemäß der vorliegenden Offenbarung;
• 5 eine schematische Darstellung eines alternativen Beispiels einer Vorrichtung zum Durchführen eines Verfahrens gemäß der vorliegenden Offenbarung, bei der eine Substrathandhabungseinrichtung als horizontales Transportsystem mit Rollen implementiert ist;
• 6 eine schematische Darstellung eines alternativen Beispiels einer Vorrichtung zum Durchführen eines Verfahrens gemäß der vorliegenden Offenbarung, bei dem eine Prozessmedienbereitstellungseinrichtung ein Prozessmedienbad aufweist; und
• 7 ein schematisches Ablaufdiagramm eines Verfahrens 1000 gemäß dem Stand der Technik.

Examples of the disclosure will be explained in more detail below with reference to the accompanying drawings. Show it:

• 1a a schematic flow diagram of a method according to the prior art;
• 1b a schematic flow diagram of a method according to an embodiment;
• 2 a schematic flow diagram of a method according to an embodiment having an optional step of cleaning organic compounds;
• 3 a schematic flow diagram of a method according to an embodiment, comprising a step in which at the same time carried out by means of the ozone-based treatment, the cleaning, the removal of the porous silicon and the metal cleaning;
• 4 a schematic representation of one for carrying out a method according to the present disclosure;
• 5 a schematic representation of an alternative example of an apparatus for carrying out a method according to the present disclosure, in which a substrate handling device is implemented as a horizontal transport system with rollers;
• 6 3 is a schematic illustration of an alternative example of an apparatus for performing a method according to the present disclosure, wherein a process media provider includes a process media pool; and
• 7 a schematic flow diagram of a method 1000 according to the prior art.

Hereinafter, examples of the present invention will be described in detail and using the attached drawings. In the following description, many details are set forth in order to provide a more thorough explanation of examples of the disclosure. However, it will be apparent to those skilled in the art that other examples may be implemented without these specific details. The features of the different examples may be combined with each other unless features of a corresponding combination are mutually exclusive or such combination is expressly excluded. In the following, the same reference numerals are used for elements having the same or a similar function, so that even without a detailed embodiment, the description of these elements is interchangeable.

1a shows a schematic flow diagram of a method 1000 according to the prior art. A step 1010 includes etching the semiconductor substrate to texture it. In a subsequent step 1020 Rinse the semiconductor substrate to remove residues of substances or materials in step 1010 have come into contact with the semiconductor substrate. In one step 1030 An alkaline post-cleaning of the semiconductor substrate is carried out to remove porous silicon. The next step will be 1020 executed to rinse the semiconductor substrate. In one step 1040 an acidic post-cleaning of the semiconductor substrate for metal cleaning takes place. Then the rinse is done 1020 re-executed to the semiconductor substrate of residues of acid post-purification 1040 to clean. In one step 1050 a drying of the semiconductor substrate takes place.

1b shows a schematic flow diagram of a method 100 according to an embodiment. The procedure 100 includes an optional step 110 in which an etching of the semiconductor substrate takes place, for instance in order to obtain a texturing of at least one surface of the semiconductor substrate.

One or more targets of the etch 110 and / or a major focus thereof may be on an acidic isotropic texture provided with an additive to multi-crystalline diamond wire sawn To treat silicon substrates. The additive may be organic or inorganic. An additive used may comprise as a component a polymer. The etching 110 can be done in different ways. One type is, for example, a metal-assisted chemical etching using metal particles. This can also be described by the English technical term "Metal Assisted Chemical Etching (MACE)". It is also possible to use an acidic isotropic texture, ie mixture of substances. Such an acid isotropic texture with organic and / or inorganic additives may be for example a combination of hydrofluoric acid, nitric acid (HNO ₂ ) and at least one additive. Optionally, water can also be added so that the acid isotropic texture with additive can also be a combination of hydrofluoric acid, nitric acid, water and the additive. In the etching solution, as in DE 10 2016 210 883 A1 described, with a small proportion of at most a few wt.% An additive from the group consisting of alcohol, surfactant, glycol be included. By the etching 110 For example, etching rates and the appearance of the semiconductor substrate surface may be adjusted depending on the temperature and / or the time. In one example, the etch may be done without additive.

Typically, temperature ranges in the range of 10 ° C to 30 ° C and etches in the range of 0.5 minutes to 10 minutes can be used. Additive and / or additive residues may adhere to the surface and alter the wetting behavior for further steps and / or inhibit the attack of further etchants, i. H. inhibit. The additive may have one or more components and thus also be understood as an additive or a combination of several additives. The use of several additives can be such that the combination of the additives co-operate only in a solution or in the bath used, which means that when the additives are combined, no interaction takes place per se. The detachment of impurities on the wafer, such as metals and / or metal ions, can also be inhibited.

Alternatively or additionally, an electrochemical etching can also be carried out. Other examples of use during the etching process include, for example, edge chemical isolation, surface smoothing, d. h., performing a polishing, selective emitter removal, removal of sawing damage, particularly in diamond wire-sawn silicon substrates, a single-side treatment (one-side treatment), or a treatment of both main sides (two-side treatment). That is, the use of an acidic isotropic texture may optionally be accomplished using an additive, which additive may be organic or inorganic.

The etching 110 may result in residues on at least one of the surfaces of the semiconductor substrate. These residues may be porous silicon, may alternatively or additionally include texture additives, ie, metal contaminants, but may alternatively or additionally include organic contaminants. According to an advantageous aspect of the present examples, the ozone-based treatment may be used to remove the porous silicon and / or perform the metal cleaning, that is to remove the metal residues.

For removal, in particular of the additive components, an optional step 120 be executed, in which a rinsing of the semiconductor substrate takes place. The rinse 120 or the removal of the additive components can take place in at least one step and / or one pass. This means it can also be flushed more often. The rinse 120 may comprise contacting the semiconductor substrate with water, that is, a medium of the rinsing process 120 can be water. Alternatively or additionally, ozone, hydrofluoric acid, hydrogen chloride and / or other agents may also be used. The flushing process 120 may be in a temperature range of, for example, at least 5 ° C and at most 90 ° C, for example, to avoid the boiling of water. For example, a rinsing process, which can be referred to by the technical term "Quick Dump Rinse", can be used. Overflow rinse and / or cascade rinse can be used. For example, a purging process may involve a fixed consumption of purging medium, advantageously, the purging process may be dynamically adjusted to the degree of contamination of the wafer and / or the purging medium.

The step 120 can be carried out in particular when the method is the step 110 includes.

Alternative to the step 110 can for the step 130 the ozone-based treatment, with which removal of porous silicon and / or metal can be obtained, also a pre-etched semiconductor substrate can be provided. As explained in detail below, not only the removal of porous silicon and / or the metal cleaning can be performed by the step. Rather, a cleaning of organic residues from the surface can be obtained, ie, a cleaning by removing substances to be cleaned off.

The ozone-based treatment 130 Thus, the etching of porous silicon, ie, the removal thereof, and the metal cleaning combine in one step, wherein each of the two cleaning aspects independently can be obtained, for example, if no porous silicon or metal is present. If the ozone-based treatment is used only for one of the removal of porous silicon and the metal cleaning, then the other one can be omitted, or be carried out in a separate process step, for example. Before the ozone-based treatment. The removal of porous silicon on the surface of the textured silicon substrate may be carried out by an alkaline post-cleaning and / or by the treatment with ozone.

The metal cleaning of the surface of the textured silicon substrate may be carried out by an acid post-cleaning and / or by the treatment with ozone. The metal cleaning may also be obtained by contacting the semiconductor substrate to be cleaned with an aqueous solution comprising water and at least one of hydrogen chloride (HCl) and hydrofluoric acid (HF). Alternatively or additionally, a solution comprising hydrofluoric acid, hydrogen chloride and ozone can also be used.

Alternatively or additionally, the ozone treatment may also be used to remove organic residues. The ozone-based treatment 130 For example, it can be executed in at least one step, which means that it can also be executed repeatedly or iteratively.

Ozone concentrations of ozone contained, for example, in a liquid, such as aqueous solution in a bath in which the semiconductor substrate is dipped or which is sprayed over the semiconductor substrate may be in a range of at least 1 to at most 150 ppm. Preference is given to concentrations of at least 5 or at least 10 ppm. Such a solution may comprise water, an acid, hydrofluoric acid and / or hydrogen chloride. The solution may preferably have a pH in a range of at least 0 and at most 7 and be used at a process temperature of at least 5 ° C and at most 80 ° C. Preference is given to temperatures of at least 20 ° C and at most 65 ° C or at least 50 ° C and at most 65 ° C. This means that in the ozone-based treatment, the ozone may be dissolved in or part of an aqueous solution, so that a Wetting the semiconductor substrate with the aqueous solution causes the aqueous solution to react with the semiconductor substrate (s) thereon. The ozone can occur in addition to the dissolved medium state, even in the form of elementary gas bubbles and actively act the ozone-based treatment. The wetting can take place by means of a bath, into which the semiconductor substrate is introduced, and / or by means of spraying.

The ozone-based treatment is particularly advantageous combined with the cleansing of the organic matter. Such a method may thus also be referred to as a method for treating etched surfaces of a semiconductor substrate using ozone-containing medium. Thus, the embodiments described herein and in this context relate to a method and apparatus for treating a textured silicon substrate, and more particularly to a method of cleaning using an ozone-containing medium. It is compared to the prior art, not focused on the rinse, but on a separate step using the ozone-containing medium, in which the corresponding and to be removed substances are removed by the ozone. This means that the ozone interacts with the semiconductor substrate or the residues.

If the procedure 100 designed so that it is the step 110 this may be prior to ozone-based treatment 130 are performed and performed to obtain the textured silicon substrate. As already explained above, the ozone-based treatment with hydrofluoric acid and / or hydrogen chloride can be carried out. Again, etching may include at least one of metal assisted chemical etching, electrochemical etching, acidic isotropic texture etching, and acid isotropic texture etching with organic and / or inorganic additives. The etching may alternatively or additionally comprise chemical edge isolation and / or surface smoothing and / or selective emitter removal and / or saw damage removal, and / or one-sided treatment or two-sided treatment.

After the step 130 can in an optional step 140 a new flushing be performed. The step may be the same or similar to the same or similar rinsing steps 120 and or 1020 , Like the other rinsing steps, rinsing can be done in step 140 be carried out in a temperature range of 5 ° C to 90 ° C.

The procedure below follows 100 the optional step 150 in which the drying of the semiconductor substrate takes place. The drying can be carried out in a temperature range of at least 0 ° C, ie, a state in which water is liquid, to allow evaporation of the raw material water. A temperature range of at least 25 ° C and at most 100 ° C is preferred. The temperature can be over a course of the step 150 be constant or variable. For example, a variable temperature history with increasing temperature can help to keep a material stress in the semiconductor substrate low. At low temperatures or low temperature differences can be dispensed with such a step of temperature adjustment. The step 150 can be carried out in the medium air. Alternatively or additionally, instead of air or in addition to the air, an inert gas may be arranged. The step 150 can also be carried out using an IPA dryer (IPA = isopropyl alcohol). Alternatively or additionally, it is also possible to use a hot air which, for example, conducts a stream of nitrogen over the semiconductor substrate.

The step 140 can after the ozone-based treatment and before drying in the step 150 take place or take place before the end of the process. The end of the process may include depositing the semiconductor substrate, which may also be understood as drying, for example in ambient air. The step 140 can include by wetting the semiconductor substrate with a medium comprising at least one of water, ozone, hydrofluoric acid and / or hydrogen chloride. A possible ozone concentration is in the range of 1 ppm to 5 ppm or less. The time at which the semiconductor substrate in the step 140 Ozone is contacted and / or concentrated to remove any residue from the media used in previous steps during the step 130 a treatment of the substrate itself with ozone takes place.

The method may be adapted based on different adjustment parameters and / or materials used such that the ozone-based treatment is configured to effect one or more of the alkaline post-cleaning, the removal of porous silicon, the metal cleaning, and the removal of organic compounds. For example. For example, adding components, ingredients or additives to the cleaning medium may cause different settings. According to one embodiment, all three cleaning steps may be obtained in a common pool at at least approximately constant conditions. A purification of organic impurities can be carried out particularly effective at higher temperatures and higher ozone concentrations and can - in itself - be carried out only with ozone and water. An additional removal of porous silicon can be obtained by adding hydrofluoric acid. It is known to perform a metal cleaning only with HF / HCl. Use of a combination of hydrofluoric acid, hydrogen chloride and ozone and / or a combination of hydrofluoric acid and ozone allows all three steps to be carried out simultaneously, removal of organo compounds, metal residues and porous silicon.

2 shows a schematic flow diagram of a method 200 according to an embodiment. Compared with the procedure 100 includes the method 200 an optional step of cleaning 260 of organic compounds. Although the step 260 is shown as being before the step 130 Alternatively, it can also be carried out subsequently or simultaneously. Cleaning to remove organic compounds makes it possible to obtain a pure surface and thus high-quality products.

Although alkaline post-cleaning or acid post-cleaning, which may be carried out in addition to the ozone-based treatment, can remove some residues of the etching, in particular porous silicon and metal impurities, other impurities may be left behind. In methods according to embodiments, therefore, cleaning of the surface of the textured silicon substrate to remove organic compounds is performed. The cleaning can be carried out as a separate step or advantageously combinatorially in the ozone-based treatment. The organic compounds are located on the surface of the textured silicon substrate and may be, for example, residues of the etching process and / or the contact of the semiconductor substrate with other substances and / or persons. By cleaning the surface of the organic compounds, a highly clean textured surface is obtained which can be used for high quality processed products, such as solar cells.

The step 260 includes so cleaning the surface of the textured silicon substrate to effect removal of organic compounds that are on the surface of the textured silicon substrate. The step 260 may further for removing porous silicon on the surface of the textured silicon substrate and for performing a metal cleaning of the surface of the textured silicon substrate and thus as an integral step with the step 130 be executed. The cleaning can be different 260 , the step 130 comprising removal of porous silicon and / or carrying out the metal cleaning also take place in at least partially separate steps. This means that at least two of the three purification steps can also be carried out in one common step or, as it is in 3 is shown, all three cleaning steps in a common step 310 can be executed.

3 shows a schematic flow diagram of a method 300 according to one Embodiment, a step 310 comprising, by means of the ozone-based treatment, approximately equal to the step 130 , at the same time the cleaning from the step 260 , the removal of the porous silicon and the metal cleaning takes place.

Below is explained how, for example, the step 260 can be executed. The cleaning in the step 260 To remove the organic compounds may be wholly or partly by contacting the silicon substrate with an oxidative component. Exemplary oxidative components are, for example, hydrogen peroxide (H ₂ O ₂ ) or ozone (O ₃ ). Alternatively or additionally, the silicon substrate may also be associated with an alkaline component, for example potassium hydroxide (KOH). Alternatively or additionally, a RCA (Radio Cooperation of America) cleaning can be carried out, which includes a wet chemical cleaning process. RCA cleaning may include cleaning the semiconductor substrate in two baths. A first bath may include an aqueous solution of ammonium hydroxide and hydrogen peroxide. A second bath into which the semiconductor substrate is subsequently added may include an aqueous solution of hydrochloric acid and hydrogen peroxide. The cleaning 260 can be carried out at room temperature, but can also be carried out in other temperature ranges. By using a slightly higher temperature range, for example, in a range between 40 ° C and 70 ° C, a high purification efficiency can be obtained. This means that the cleaning can take place in a bath, for example in a so-called batch process. The method may also include a plurality of baths into which the respective semiconductor substrate is successively brought. Alternatively, at least one bath can be replaced by wetting with the liquid to be applied, for example by using spray nozzles.

A sequence of the individual cleaning steps carried out for the removal of the porous silicon by a known alkaline post-cleaning or the ozone-based treatment and / or the metal cleaning by a known acid post-cleaning or the ozone-based treatment and / or the cleaning by the ozone-based treatment is arbitrary. That means it can also, unlike in 2 shown, also the step first 130 and then the step 260 be executed. The alkaline post-purification can be carried out, for example, by carrying out the step 1030 to be obtained. The acid post-purification can be done, for example, by performing the step 1040 be executed.

Alternatively, to obtain the purification of all three components, the organic compounds, the porous silicon and the metal impurities, ozone can also be used by the step 130 is performed. By using ozone, it becomes possible to combine the purification steps with each other to carry out at least two of the purification steps in a common step.

In the present case, it has been recognized that ozone can be removed to remove porous silicon and / or perform metal cleaning and / or cleaning of the organic compounds by treating the surface of the textured silicon substrate with the ozone-based treatment.

4 schematically shows an example of a device 40 for performing a method according to the present disclosure. The device 40 includes a process media provider for providing media for cleaning, alkaline post-cleaning, and acid post-cleaning of the surface. The device 40 further comprises a substrate handling device configured to surround the substrate 82 to position. At the substrate 82 For example, it can be a wafer. More specifically, the process media provider may be configured to roll 86 having a transport and a wetting of the substrate 82 with an acidic or alkaline and / or ozone-containing medium. For example. At least one of the roles 86 Have a cavity for receiving the medium and be formed so that the medium can pass through a lateral surface through to the substrate, for example. Over a porous surface of the roll. Alternatively or additionally, the process media supply device may comprise a media pool in which the acidic or alkaline and / or ozone-containing medium is located. It is understood that the device 40 may have multiple roles and / or media pool to the substrate 82 to connect with different media. Alternatively, the roller and / or the basin between individual steps can be emptied, optionally cleaned and refilled.

The substrate handling device has rollers 86 on top of that the substrate 82 is transported. The roles 86 may represent a horizontal transport system, that is, there may be a functional integration between process media supply device and substrate handling device. The roles 86 may have the function of bringing the medium to the bottom of the substrate 82 to transport. For example, the roles 86 be arranged for this purpose at least partially in the medium and have a porous or spongy surface or provide the medium from an inner hollow body. This allows the bottom of the substrate 82 wetted with the medium and thus treated.

5 shows an alternative example of a device 50 for carrying out a method according to the present disclosure, in which the substrate handling device again as a horizontal transport system with rollers 86 over which the substrate 82 transported is implemented. The device 50 can be similar to the one in DE 10 2009 060 931 A1 or WO 2011/076920 A1 be described device, so that, for example, the device 50 for the treatment of silicon wafers 82 is shown as silicon substrates, in the direction of passage of these silicon wafers 82 , They lie along a horizontal transport path, the transport rollers 86 on transport shafts 87 is formed. Several silicon wafers can be side by side through the plant 50 be driven and many in a row with a small distance. Above the transport path along the the substrate 82 is moved, the process media supply device, a stillpipe 94 provided as a wetting device, which is a distance of a few centimeters to the top of the substrates 82 , about silicon wafer and extends over the entire width of the transport path. The stillpipe 94 or several stillpipes 94 one behind the other cover the transport path in length. The distance between the stillpipes 94 may for example be about 15 cm, but possibly also a little more or a little less or change in the course of the transport path.

Furthermore, on the stillpipe 94 a subsequent dosing 98 be provided for post-dosing of additive as a separate connection. Here, an additive mentioned above or several of them can be added or the etching solution 85 be dosed. This can be so short before the application of the etching solution 85 from the stillpipe 94 take place that evaporation of the aforementioned volatile additives is kept very low or can be completely avoided.

The stillpipe 94 has several splash nozzles on its underside 96 on, which may be formed as simple holes, openings or slots. Through them, the medium or the etching solution 85 leak out and onto the top of the silicon wafer 82 come and distribute themselves there, as it is shown. Unlike the in DE 10 2009 060 931 A1 described alkaline etching solution, a different, for example. Acid etching solution will be used, as it is, for example, in the DE 10 2007 063 202 A1 is described, in addition, the cleaning takes place. A method described there can be carried out in two steps. Both steps can use acid etching solutions. In the first step, focusing on the texture of the top, and in the second step on a polish from the bottom. Between the steps a rinsing with water can take place.

According to one embodiment, the process media supply device may alternatively or additionally to the surge nozzles 96 lower spray nozzles and upper spray nozzles to the medium from both sides with respect to the substrate 82 provide to both major surfaces of the wafer 82 to treat. Alternatively, spray nozzles may be provided only on one side. Although in 5 five splash nozzles 96 are shown on, another number, z. B. only one nozzle or a higher number, such as two, three, four, six, ten or more, may be provided.

6 shows an alternative example of a device 60 for performing a method according to the present disclosure, wherein the process media providing device comprises a process media bath 122 in which is the medium 84 , for example, an acidic medium is located.

A substrate handling device 124 , in the 6 only shown very schematically is formed to the substrate 82 for example, in a horizontal orientation (left part of 6 ) or in vertical orientation (right part of 6 ) in the medium 84 immerse. The substrate handling device 124 For this purpose, it may comprise suitable holders or grippers for holding or gripping substrates one by one or more substrates at a time and into the medium 84 immerse.

In example, the substrate handling device can transport rollers or in DE 10 2012 210 618 A1 Having described in more detail transport chains, which are formed around a substrate or a plurality of substrates floating over the surface of the medium 84 to lead or which are adapted to a substrate or more substrates in the medium 84 immerse.

The medium 84 may each be at least one medium of the respective process step described in connection with the methods of the disclosure set forth herein.

Although some aspects of the present disclosure have been described as features associated with a device, it will be understood that such description may also be considered as a description of corresponding method features. Although some aspects of the present disclosure have been described as features associated with a method, it will be understood that such description is also a description of corresponding features of the Device and the functionality of the device can be considered.

The examples described above are only illustrative of the principles of the present disclosure. It should be understood that modifications and variations of the arrangements and details described are obvious to those skilled in the art. It is therefore intended that the disclosure be limited only by the appended claims and not by the specific details set forth for the purpose of describing and explaining the examples.

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 2010/0055398 A1 [0002]
• EP 2232526 B1 [0002]
• DE 102013218693 A1 [0003]
• US 2015/0040983 A1 [0004]
• CN 103132079 A [0006]
• US 6503333 B2 [0008]
• DE 102010054370 A1 [0008]
• DE 102016210883 A1 [0020]
• DE 102009060931 A1 [0047, 0049]
• WO 2011/076920 A1 [0047]
• DE 102007063202 A1 [0049]
• DE 102012210618 A1 [0053]

Claims (31)

A method (100; 200; 300) for treating a surface of a textured silicon substrate that comprises ozonation treating (130; 310) the surface of the textured silicon substrate for removal of porous silicon and / or metal cleaning and / or organic compound cleaning cause, has. Method according to Claim 1 wherein the ozone-based treatment (130; 310) is conducted at an ozone concentration of 1 to 150 ppm in an ozone-containing acidic medium. Method according to Claim 1 or 2 wherein ozone-based treatment (130; 310) is performed with HF and / or HCl. Method according to one of Claims 1 to 3 wherein the ozone-based treatment (130; 310) is performed in a pH range of 0 to 7. Method according to one of Claims 1 to 4 wherein the ozone-based treatment (130; 310) is performed in a temperature range of 5 ° C to 80 ° C. Method according to one of Claims 1 to 5 , further comprising: etching (110) performed prior to the ozone-based treatment (130; 310) to obtain the textured silicon substrate. Method according to Claim 6 wherein the etching (110) comprises at least one of metal assisted chemical etching, electrochemical etching, acidic isotropic texture etching, or acid isotropic texture etching with organic or inorganic additives. Method according to one of Claims 6 or 7 wherein the etching (110) comprises chemical edge isolation, surface smoothening, selective emitter removal, saw damage removal, unilateral treatment, or two-sided treatment. Method according to one of Claims 1 to 8th , further comprising: drying (150) performed after ozone-based treatment (130; 310). Method according to Claim 9 wherein the drying (150) is carried out at a temperature which is in a temperature range of 25 ° C to 100 ° C. Method according to one of Claims 9 or 10 wherein the drying (150) is carried out at a constant temperature or has a variable temperature profile. Method according to one of Claims 9 to 11 wherein the drying (150) is carried out with a medium, wherein the medium comprises at least one of air and / or inert gas. Method according to one of Claims 1 to 12 , further comprising at least one of: rinsing (120; 140) comprising between etching (110) and ozone-based treatment (130; 310) and / or between ozone-based treatment (130; 310) and drying (150). Method according to Claim 13 wherein the purging (120; 140) is by means of a medium, the medium comprising at least one of water, ozone or HF. Method according to Claim 14 wherein, when the purge medium (120; 140) comprises ozone, purge (120; 140) occurs at an ozone concentration of 1 to 5 ppm. Method according to one of Claims 13 to 15 wherein the purging (120; 140) is performed in a temperature range of 5 ° C to 90 ° C. Method according to one of Claims 1 to 16 further comprising cleaning (260) the surface of the textured silicon substrate prior to the ozone-based treatment (130; 310) to effect removal of organic compounds present on the surface of the textured silicon substrate. Method according to Claim 17 wherein the cleaning (260) of the surface is carried out with an oxidative and / or an alkaline component. Method according to Claim 18 wherein the oxidative component comprises at least one of hydrogen peroxide and ozone and / or the alkaline component comprises potassium hydroxide. Method according to Claim 17 wherein cleaning (260) of the surface comprises RCA cleaning. Method according to Claim 20 wherein the RCA purification comprises a two-bath purification, wherein a first bath includes an aqueous solution of ammonium hydroxide and hydrogen peroxide, and a second bath includes an aqueous solution of hydrochloric acid and hydrogen peroxide. Method according to one of Claims 17 to 21 wherein cleaning (260) of the surface causes removal of porous silicon, organic compounds and / or texture additives. Method according to one of Claims 17 to 22 wherein the cleaning (260) of the surface occurs at a temperature in the range of 40 ° C to 70 ° C. Method according to one of Claims 17 to 23 further comprising etching (210) performed prior to cleaning (260) the surface. Method according to Claim 24 wherein the etching (210) comprises at least one of metal assisted chemical etching, electrochemical etching, acidic isotropic texture etching, or acid isotropic texture etching with organic or inorganic additives. Method according to Claim 24 wherein the etching (210) comprises an acidic isotropic texture etching with organic or inorganic additives, and the texture comprises HF, HNO ₃ and an additive or HF, HNO ₃ , H ₂ O and at least one additive. Method according to Claim 26 wherein the etching (210) occurs at a temperature in the range of 40 ° C to 70 ° C. Method according to one of Claims 26 or 27 wherein a duration of the etch (210) is in the range of 0.5-10 minutes. Method according to one of Claims 24 to 28 wherein the etching (210) comprises chemical edge isolation, surface smoothening, selective emitter removal, saw damage removal, unilateral treatment or bilateral treatment. Apparatus for carrying out a method according to one of Claims 1 to 29 comprising a process media providing means for providing an ozone-based processing medium and a substrate handling means for positioning the silicon substrate to treat the surface. Device after Claim 31 in which the process media supply device has at least one porous roller for transporting and wetting the substrate and / or a process media basin.

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