EP3298181A1

EP3298181A1 - Method for applying an overgrowth layer onto a seed layer

Info

Publication number: EP3298181A1
Application number: EP15724285.0A
Authority: EP
Inventors: Gerald Kreindl; Harald ZAGLMAYR; Martin EIBELHUBER
Original assignee: EV Group E Thallner GmbH
Current assignee: EV Group E Thallner GmbH
Priority date: 2015-05-21
Filing date: 2015-05-21
Publication date: 2018-03-28
Also published as: US20180120695A1; CN108368640A; JP6799007B2; JP2018523287A; WO2016184523A1; US10241398B2

Abstract

The invention relates to a method for applying a masked overgrowth layer (14) onto a seed layer (2) for the production of semiconductor components, characterized in that a mask (6) for masking the overgrowth layer (14) is embossed on the seed layer (2).

Description

Method of applying an overgrowth layer to a seed layer

Description

The invention relates to a method for applying a

Upper growth layer on a seed layer according to claim 1.

In the semiconductor industry, the production of high-purity but, above all, defect-free layers is of great importance for the production of semiconductor components. Defects, especially crystal defects, have a decisive influence on the functionality and

Longevity of semiconductor devices. Many many

Semiconductor devices are fabricated directly on single crystal substrates that are extremely high in purity and relatively low in size

Own defect density. Such semiconductor substrates are processed by special processes, in particular the Czochralski process,

produced. Such methods usually produce a very large single crystal, which is sawn or cut in further process steps to the individual substrates.

Very often it is necessary to use more monocrystalline layers

correspondingly low defect structure directly on already existing surfaces. These monocrystalline layers can be produced by different processes. In order to produce high-purity and, above all, defect-free layers, it is very often the case of the lateral overgrowth method. In order to obtain relatively defect-free, monocrystalline layers, a mask is produced on a seed layer surface in a first process step. The mask covers most of the seed layer surface. At well-defined places, the mask has mask openings upper exposing the parts of the surface. The mask is produced in the prior art mainly by photolithographic methods.

Masks are mostly produced by photolithographic processes with several process steps. In a first process step, a photoresist must be applied. Thereafter, the photoresist is exposed, developed and etched. In many cases, no simple, based on polymer-based, photoresists can be used because the masks must consist of a hard material layer. Accordingly

the material separation and, above all, the etching processes become more difficult, more complicated and more expensive.

The object of the present invention is therefore to specify a more efficient method for applying a UV growth layer to a seed layer.

This object is achieved with the features of claim 1.

Advantageous developments of the invention are specified in the subclaims. The scope of the invention also includes all

Combinations of at least two of in the description, the

Claims and / or the figures given characteristics. In the case of indicated items, it is intended that also be mentioned within the cited

Limit values are considered limits and apply in

any combination can be baskspruchbar. The invention is based on the idea of a method for

Application of a masked overgrowth layer on a seed layer for the production of semiconductor devices in such a way that a mask for masking the upper layer of growth is embossed on the seed layer.

The invention relates to a, in particular independent, aspect of a method for producing masks, in particular

Hard masks, using an imprint technique. The masks are used to make lateral growth structures.

According to the invention, in particular epitaxial and / or monocrystalline shaped by the inventive embossed mask

Nanodots and / or nanowires and / or other nanostructures.

A core of the invention consists in particular in the application of an imprint technique and the use of suitable embossing materials as mask material, which are structured with the aid of imprint technology and which are further processed, in particular by a process step

Heat treatment, can be converted into an oxide.

The use of imprint technologies makes the most

Process steps of a typical photolithography process superfluous, resulting in a significant time savings and thus a more efficient

Production of the semiconductor devices are made possible.

The embossing composition (mask material) is applied to the germ layer, in particular in liquid form, and then by a Imprintprozess structured and converted in a further process step in particular in a hard material layer.

In other words, or more generally, or according to an independent aspect, the invention describes a method with which a mask for producing a semiconductor component can be produced by means of imprint lithography. The mask thus serves to produce a lateral growth structure.

The overgrowth structure is preferably a monocrystalline and / or epitaxial layer of a

Coating material (or overcoat layer material) which grows on a seed layer surface and continues it monocrystalline and / or epitaxially. According to the invention, a monocrystalline layer is understood as meaning, in particular, a layer in which the upper has no grain boundaries. According to the invention, an epitaxial layer is understood as meaning, in particular, a layer which has at least one crystal orientation which coincides with the crystal orientation of the surface on which it grows up (seed layer).

The layer or the layer surface, starting from the

According to the invention, monocrystalline and / or epitaxial layer begins to grow, is referred to as a seed layer or seed layer surface.

substrates

The substrates are preferably wafers. The wafers are standardized substrates with well-defined, standardized diameters. However, the substrates may generally have any shape. The diameters of the substrates can generally be any however, they may preferably be of any of the standard diameters of 1 in., 2 in., 3 in., 4 in., 5 in., 6 in., 8 in., 12 in. and 18 in., and 125, 150, 200, 300 or 470 mm ,

As substrate materials, it is preferable

• silicon or

• Sapphire

used.

In the further course of the Palentschrift is generally spoken of substrates. In particular, the invention relate

Embodiments, however, predominantly on wafers.

dies

Different processes can be used for the process according to the invention

Embossing stamps are used. The stamp can be a hard stamp, a soft stamp or a foil stamp.

A hard punch is understood to mean a punch which has been produced from a material with a high modulus of elasticity (modulus of elasticity). The modulus of elasticity of the Hartstempeis lies in particular between 1 GPa and

1000 GPa, preferably between 10 GPa and 1000 GPa, more preferably between 25 GPa and 1000 GPa, most preferably between 50 GPa and 1000 GPa, most preferably between 100 GPa and

1000 GPa. For example, the modulus of elasticity of some steel grades is around 200 GPa. Preferred materials for hard punches are:

• metals, in particular

o metal alloys, especially steels,

o pure metals, in particular Ni, Cu, Co, Fe, Al and / or W,

• Ceramics, especially glasses, preferably

o Metallic glasses or

o Non-metallic glasses, in particular ■ Organic non-metallic glasses or

■ Inorganic non-metallic glasses, in particular

• Non-oxidic glasses, in particular

Halide glasses or chalcogenide glasses, or

Oxide glasses, in particular phosphatic glasses or silicate glasses, in particular aluminosilicate glasses or lead silicate glasses or alkali silicate glasses, preferably alkali earth alkaline silicate glasses, or borosilicate glasses or borate glasses, preferably alkali borate glasses, or

• alloys

A soft material is a stamp made of a material with a low modulus of elasticity. The modulus of elasticity is in particular between 1 GPa and 1000 GPa, preferably between 1 GPa and 500 GPa, more preferably between 1 GPa and 100 GPa, most preferably between 1 GPa and 10 GPa, most preferably between 1 GPa and 5 GPa , For example, the modulus of elasticity of polyamides is between 3 GPa and 6 GPa. Preferred materials for soft stamps are:

• PFPE

• silicates, in particular

o Acrylic and / or cipoxy-containing silicates and / or

o PDMS and / or

o SSQ, especially POSS.

A film stamp is understood to mean a stamp which consists of a film which is pressed into the embossing composition (mask material) by a further application device, in particular a roller. A film stamp is in the document WO2014 / 037044A1 discloses what is referred to. In the sense of the definition of a soft stamp, the film stamp can also be regarded as a soft stamp. Due to its lower bending resistance, in particular due to a small thickness of the film, the film stamp can be considered as a separate Stempelart or as an advantageous embodiment of a Weichstempcls.

seed layer

The seed layer is either a layer applied to a substrate or the substrate represents the seed layer itself. The seed layer is preferably monocrystalline and / or epitaxial.

The Kcimschichtobcrflächc has in particular a very small

Roughness. Roughness is reported as either average roughness, square roughness or average roughness. The values determined for the average roughness, the square roughness and the average roughness depth differ in particular for the same measuring section or measuring curses, but are preferably the same

Size range. Therefore, the following roughness numerical value ranges are to be understood as either average roughness, squared roughness, or average roughness. Since the seed layer surfaces are preferably around

monocrystalline and / or epitaxial layers, the classic notion of roughness may not apply here. Among the specified roughness values is in particular the height difference between the lowest, at least at one point exposed and the uppermost crystallographic level of

Seed layer surface to understand. The roughness of the seed layer surface is in particular less than 1 μm, preferably less than 100 nm, more preferably less than 10 nm, most preferably less than 1 nm, most preferably less than 0.1 nm.

The preferred crystallographic orientations of the seed layer, particularly for cubic crystal lattice materials, are {100} and {I 1 1} orientation. Other conceivable and preferred crystallographic orientations are {1 10}, {21 1}, {221}, and {31 1} orientations.

Preferred seed layer materials are

Particularly preferred seed layer materials according to the invention are: Si, sapphire.

Pr gematerial / Maskenrnaterial

As an embossing material / mask material for the formation of the mask can basically serve any kind of material that • can be deposited on a surface, especially wet-chemical, and / or

By means of lithography, in particular imprint lithography,

preferably nanoimprint lithography, is structurable, in particular, permits a correspondingly high resolution of the structures, in particular micro and / or nanostructures, and / or is etchable in the case of an existing residual layer and / or

The coating temperatures of the coating material endure without decomposing and / or deforming and / or overreacting with the coating material, and / or

^, may preferably remain incorporated in the epitaxial layer produced, without adversely affecting their properties.

Among all possible classes of materials, especially the silsesquioxanes (SSQ), in particular polyhedral oligomeric silsesquioxanes (POSS), are suitable according to the invention, since they

• can be deposited wet-chemically on a surface,

• easily structured by imprint processes,

Are thermally and / or electromagnetically curable and / or

• Can be converted into glass, which is chemically and

physically very inert.

The invention is further based on, in particular independent, idea to produce a Prägemasse from a special mixture. The mixture consists of at least one main component and

at least one minor component. The main component is preferably a silsesquioxane. The following materials would also be conceivable according to the invention:

Polyhedral oligomeric silsesquioxane (POSS) Polydisethylsiloxane (PDMS)

Tetraethyl orthosilicate (TEOS)

• poly (organo) siloxanes (silicone)

Perfluoropolyether (PFPE)

The minor components may consist of any organic and / or inorganic compound. These secondary components can an arbitrarily complicated _"organic with preference to have structure. Accordingly, links may be composed of a combination of the elements of the following list. Of course, all of the chemical compounds in the list can exist as a monomer or polymer. At least one of the secondary components is preferably an organic, in particular one of the following compounds: at

• Alcohol. In a very particular embodiment, the minor component can belong to the same functional group as the organic, functional groups of the main component. In a further particular embodiment, the secondary component may already have been bonded to the main component by a chemical reaction, in particular by an addition and / or condensation and / or substitution reaction.

Solvents are always used to dissolve the main component, the initiators and the organic component according to the invention, with the aid of which the adjustment and / or influencing of the hydrophilicity or hydrophobicity takes place. In the course of the production process, the solvents are preferably removed from the embossing composition according to the invention or escape by themselves. Preference is given to using one of the following solvents:

The main components and the minor components are combined with initiators which initiate the chain reaction in one

corresponding stoichiometrically correct ratio mixed. By mixing the main component with the minor component and the initiator, activation of the initiator leads to polymerization, especially or at least predominantly between organic parts of the main components. It may be that the minor components partially participate in the polymerization. In particular, only the main components polymerize with each other. In the polymerization arise long-chain molecules and / or entire 2D and / or 3D networks, preferably with a specially adjustable number of monomers. The number of monomers is greater than 1, more preferably greater than 10, more preferably greater than 100, most preferably greater than 1000, most preferably polymerizing the monomers into a complete 2D and / or 3D network.

In the following, the words PrSmaterial and mask material are used as synonyms.

Coating material (also upper layer material)

The coating material is in particular to

Halbleitcrmaterialien. The coating material is preferably identical to the seed layer material, so that the seed layer passes through the process according to the invention, preferably seamlessly, by overgrowth of the mask openings into the overgrowth layer to be produced. However, seed layer material and coating material can also be different.

Suitable coating materials and / or seed layer materials are, in particular, the following materials:

•

Materials preferred according to the invention are: Si, GaAs, GaN, InP, InxGa _{(j -X)} N, InSb, InAs.

process

In a preferred according to the invention, in particular first,

Process step, the provision of a substrate with a seed layer surface. The Kcimschichtoberfläche may either be the surface of a deposited on the substrate seed layer or, in particular consisting of the substrate material, substrate surface itself serves as Kcimschichtoberfläche. The seed layer surface serves in the application of the

Overgrowth layer, in particular as nucleation point for the to be produced, in particular monocrystalline and / or epitaxial,

Overgrowth layer. Preferably, the seed layer consists of the same materal valley as the coating material from which the overgrowth layer is produced. However, the invention also conceivable is the

Use of different materials. It is important, above all, that the seed layer ensures the nucleation of the overgrowth layer and according to the invention provides access to the seed layer surface, in particular in areas to which the overgrowth layer is intended to grow.

In special preferred embodiments of the invention, the seed layer can thus be applied only at defined locations on a substrate surface, that is to say it is not over the entire surface.

In a further preferred, in particular second, process step according to the invention, the deposition of the mask material onto the cement layer surface takes place. In particular, the application can be made by the following methods: Physical precipitation methods, in particular PVD, and / or

Chemical deposition processes, in particular CVD, preferably PE-CVD, and / or

Wet-chemical deposition processes, and / or

• Belackung, in particular Schleuderbelackung or

Spray Coating.

In a further preferred, in particular third, process step according to the invention, the positioning of a prism stamp over the deposited mask material takes place. In special embodiments, alignment of the embossing stamp relative to the substrate and / or the seed layer surface is performed. In particular, the

Alignment based on alignment marks.

In a further preferred, in particular fourth, process step according to the invention, the structuring of the mask material takes place. The structuring is carried out according to the invention preferably by a

Imprint lithography method, most preferably by a

Nanoimprintlithographiemethode. The aim of the Imprintlithogaphiemethode is the structuring of the mask material. The mask material should be structured so that in a minimum number of

Structuring steps, a layer with a defined number of mask passages / mask openings per unit area, arises. The number of structuring steps c is in particular less than 10, preferably less than 5, more preferably less than 3, on

most preferably less than 3. The number of

Mask passages / mask openings is in particular greater than 1 per m ² , preferably greater than 10 ³ per m ² , more preferably greater than 10 ⁷ per m ² , most preferably greater than 10 "per m ² , on

most preferred greater than 10 ¹³ per m ² . In a preferred embodiment, the raised ones displace

Structures of the embossing stamp the mask material up to the stop of the structures on the germ layer surface. This prevents the formation of a residual layer and directly marks the desired mask structure. A subsequent etching step for exposing the areas of the seed layer surface to be coated with the over-growth layer material can then be dispensed with.

In a further preferred, in particular fifth, process step according to the invention, the curing of the mask material takes place.

According to a first, less preferred, embodiment of the

When cured, the mask material is thermally cured. The thermal curing is carried out by heat. In particular, the temperature at the mask material is more than 50 ° C, preferably more than 100 ° C, more preferably more than 250 ° C, even more preferably more than 500 ° C, even more preferably more than 750 ° C. A preferred temperature is between 500 ° C to 600 ° C. By choosing special thermal initiators one can drastically reduce the temperature range. An even more preferred temperature in this case is between 50 ° C and 200 ° C. In the case of thermal curing, the heat can be introduced via the substrate and / or the stamp. If the heat is introduced via the stamp, the stamp should have the highest possible thermal

Conductivity, the lowest possible heat capacity and / or have the lowest possible coefficient of thermal expansion.

In a second and preferred embodiment of the curing, the curing takes place by electromagnetic radiation. In this case, the substrate and / or the stamp are at least partially, preferably predominantly, transparent for the respective wavelength range. With particular preference, the stamp has the above transparency, so that any substrates can be used. If the curing is carried out by ultraviolet light (UV light, preferably), the electromagnetic radiation has in particular a wavelength in the range zwi1e0nnm and 2000nm, preferably between l 0nm and 1500nm, more preferably zwisch1e0nnm and 1000nm, most preferably between 10nm and 500nm, most of all between 10nm and 400nm.

Curing is usually associated with the production of gases. These gases are preferably expelled before a top wax of the mask to avoid blistering. In a particularly preferred embodiment according to the invention, the curing of the mask takes place in the coating chamber, in particular simultaneously with the coating. This will make it possible to get an extra

Save process step. The curing of the mask in the

The coating chamber is preferably carried out when

(i) the coating thickness above the curing temperature,

in particular the temperature which allows a complete outgassing of the mask is and / or

(ii) the outgassing process is stopped before the overgrowth.

If at least one of these points can not be fulfilled, the mask will be in a separate separate layer before coating

Heat treatment step cured.

Although in a curing by electromagnetic radiation preferably no thermal radiant heat is introduced into the system, can indirectly heating of the embossing stamp by

Interaction with the electromagnetic radiation arise. Therefore Preferably, the following parameter sets apply to the embossing punch, regardless of the type of curing.

The thermal conductivity of the embossing die should be as high as possible to ensure the fastest possible heat transfer. The thermal conductivity lies in particular between 0. 1 W / (m * K) and 5000 W / (m * K), preferably between 1 W / (m * K) and 5000 W / (m * K), more preferably between 100 W / (m * K) and 5000 W / (m), on

most preferably between 400 W / (m * K) and 5000 W / (m * K).

The Wärmekapizität the stamping die is as small as possible to prevent storage of heat. For most solids, the heat capacity at constant volume differs only marginally from that at moderate temperatures and pressures

Heat capacity at constant pressure. In the further course of the

Patent specification is therefore not distinguished between the two heat capacities. Furthermore, specific heat capacities are specified. The specific heat capacity of the embossing stamp is in particular less than, preferably less than 10

even more preferably less than 1, most preferably

less than 0.5 kJ / (kg * K), most preferably less than 0.1

The thermal expansion coefficient of the stamp should be as small as possible in order to minimize distortion of the stamp by the high temperature differences. The thermal

Expansion coefficient is in particular smaller than

preferably smaller than even more preferably less than 1

most preferably less than most preferably less than most preferred small a In a further preferred according to the invention, in particular sixth, process step, the demolding of the embossing stamp from

Mask material or from the cured mask. The demolding of the stamping die is preferably carried out without a

Destruction of the embossed structures of the embossing material. Hard punches can lead to demolition of the embossed structures. Therefore, soft stamps are preferably used for the embossing and thus also demoulding. More preferably, film dies are used, these are preferably peeled off and therefore allow an even more efficient separation of die and mask.

In a further preferred, in particular seventh, process step according to the invention, the etching of the residual layer takes place, if such a residual layer is present. Preferably, this residual layer is formed as thin as possible. The thinner the residual layer, the faster the etching process can be carried out. The residual layer thickness is in particular less than 1 μm, preferably less than 100 nm, more preferably less than 10 nm, most preferably less than 1 nm

In particular, one or more of the etching chemicals are suitable

following:

Inorganic acids, in particular HF, HCl, H ₂ SO ₄ , HNO ₃ and / or H ₃ PO ₄ ,

Organic acids, in particular formic acid and / or

Citric acid.

In a preferred according to the invention, in particular eighth,

Process step takes place the coating of the accessible areas of the seed layer surface. The coating is carried out in particular by Deposition of components (overgrowth layer material), in particular atoms, on the seed layer surfaces accessible through the mask openings. In particular, components are deposited on the mask surface. Therefore, components with extremely high mobility are chosen. These diffuse from the mask surface into the mask openings and are then preferably deposited on the seed layer surface, so that a continuous filling of the mask openings at the in the

Mask openings into and preferably upwardly growing seed layer takes place while the mask surfaces largely, preferably completely, remain free of the coating material.

The coating process preferably takes place at high temperatures. In particular, the coating temperature is greater than 50 ° C, preferably greater than 200 ° C, more preferably greater than 500 ° C, even more preferably greater than 1000 ° C, even more preferably greater than 1500 ° C.

The growth of the overgrowth layer takes place in particular in

different stages. These can be described in more detail in subsequent intervals with the times described below.

The growth processes preferably take place according to one of the layer growth types listed below:

• Volmer-Weber growth and / or

• Frank van der Merve growth and / or

• Stranski-Krastanov growth

At a first coating time (or interval) nucleation of the components takes place at the original

Seed layer surface of the seed layer, which is the first nucleus plane represents. At this time, due to the extremely high coating temperatures, in particular parallel to the layer growth, outgassing of the mask material. The outgassing should be completed before layer growth, otherwise the quality of the layer suffers. The outgassing is particularly due to the escape of inorganic and / or organic components, especially in SSQ materials. Due to the outgassing and combustion of the organic components, in particular in the SSQ material, this is continuously converted into a hard material, in particular a pure silicon dioxide material. This

Gasification process should therefore be separated by a separate

Process step before the coating (eighth process step) are performed. In another conceivable, but less preferred

Embodiment, however, take place coating and outgassing simultaneously, since the coating takes place anyway at high temperatures and the merger accelerates the process and less energy is consumed.

At a second coating time (or interval), the upper growth layer grows within the mask opening in the direction of the mask surface. Preferably, this growth is such that a decrease in the defect density, in particular the

Dislocation density, with increasing distance to the

Seed layer surface is detectable. The dislocation density is, in particular, less than 10 ¹⁷ cm ^-2 , preferably less than 1 0 ^{1 S} cm ^-2 , more preferably less than 1 0 ¹³ cm ^-2 , even more preferably less than 10 "cm ^{" 2} , more preferably less than 1 0 ⁹ cm ^-2 , most preferably less than 10 ⁷ cm ^"2 At the same time, the outgassing or combustion of the organic components of the mask material proceeds

Outgassing or combustion is preferably before the growth of the Overgrowth layer to the mask surface completed to minimize entrapment of gases in the upper stalk layer or prevent as completely as possible.

In a third coating time (or interval), the seed layer reaches the mask surface and begins with the lateral expansion and the formation of the remaining

Overgrowth layer that extends beyond the mask surface, and in particular a closed, unmasked area of the

Forms overgrowth layer. Preferably, the defect density, in particular the dislocation density, reaches a minimum from this point in time. The offset density is in particular less than 10 "cm ^'3 ,

preferably less than 10 ⁹ cm ^-2 , more preferably less than 10 ⁷ cm ^-2 , even more preferably less than 10 * cm ^-2 , more preferably less than 10 ³ cm ^{* 2} , most preferably less than 10 ¹ cm ^{* 2} .

In a further preferred, in particular ninth, process step according to the invention, the overgrowth layer is allowed to grow to the desired height (by further application of

Overgrowth layer material) to produce the desired end product according to the invention with a defined thickness or a

to obtain defined course of strata. The invention

End product is composed at least of a mask, the

• structured by imprint technology and

• of an overgrowth, especially in its entirety,

is surrounded.

In a further, optional, in particular tenth, process step, the newly created surface of the overgrowth layer, in particular after a successful processing, be bonded to an (optionally further) carrier substrate.

In a further, optional, in particular eleventh, process step, the first carrier substrate can be removed. Alternatively or additionally, the back (ie the side of the seed layer) can be thinned. When re-thinning a complete removal of the mask by the grinding process is possible. The complete removal of the mask occurs only when the structures grown between them are not used as a nanodot and / or nanowire structure. In this particular case, one would have one, especially lacking in

monocrystalline and / or epitaxial layer by a

Layer transfer process have transferred to the surface of a second substrate.

Further features and embodiments of the invention will become apparent from the claims and the following description of the drawings. The drawing shows in:

FIG. 1a is a not to scale, schematic,

Cross-sectional view of a first process step of an embodiment of a method according to the invention,

FIG. 1b shows a schematic, not to scale, FIG.

Cross-sectional view of a second process step of the embodiment according to FIG. 1a,

FIG. 1 c shows a schematic, not to scale, FIG.

Cross-sectional view of a third process step of the embodiment according to FIG. FIG. 1 d is a schematic, not to scale, FIG.

Cross-sectional representation of a fourth process step of

Embodiment according to FIG. 1a,

FIG. 1 e shows a not to scale, schematic,

Cross-sectional view of a fifth process step of

Embodiment according to FIG. 1a,

FIG. 1f shows a schematic, not to scale,

Cross-sectional representation of a sixth process step of

Embodiment according to FIG. 1a,

FIG. 1 g shows a not to scale, schematic,

Cross-sectional representation of a seventh process step of

Embodiment according to FIG.

FIG. 1 h shows a schematic, not to scale,

Cross - sectional view of an eighth process step of

Embodiment according to FIG.

Figure I i is not to scale, schematic, enlarged

Cross-sectional view of Figure l h,

Figure lj a not to scale, schematic, enlarged

Cross-sectional view of Figure l h,

Figure l k is not to scale, schematicc, enlarged

Cross-sectional view of Figure l h,

FIG. 11 shows a schematic, not to scale, FIG.

Cross - sectional view of a ninth process step of

Embodiment according to FIG. 1a,

Figure Im a not to scale, schematic,

Cross-sectional view of an optional tenth

Process step of the embodiment according to Figure l a, Figure I n a not to scale, schematic,

Cross-sectional view of an optional eleventh

Process step of the embodiment of Figure la and FIG. 2 shows a not to scale, schematic,

Cross-sectional view of a specific,

Ausföhrungsform according to the invention.

In the figures, the same components or components with the same function with the same reference numerals.

All figures shown represent only schematic and not to scale representations inventively conceivable

Process steps. In particular, the magnitude of the

Structures of a mask 6 for masking a seed layer 2 in the micro and / or nanometer range. On the mask 6 and the seed layer 2, an overgrowth layer 14 is applied.

FIG. 1 a shows a cross-sectional illustration of a substrate 1 with a substrate surface 10 on which the seed layer 2 is / was deposited in a first process step with a seed layer surface 2o. According to an alternative embodiment, the

Substrate 1 itself be the seed layer 2. The germ layer 2 is

preferably monocrystalline, more preferably monocrystalline and

epitaxially. In particular, the deposition process can influence the crystal orientation of the seed layer 2.

Preference is given to a (100) and / or a (1 1 1) crystal orientation.

Here, a (hkl) orientation is to be understood as a crystal orientation in which the hkl planes parallel to the surface 10 of the

Substrate 1 lie. The hkl indices are the Miller indices.

FIG. 1b shows a second process step, in which a

Mask material 3 is deposited on the surface of the seed layer 2. The deposition can be carried out by any known deposition method respectively. Since the mask material 3 is preferably deposited liquid, in particular as a sol-gel, the mask material 3 is the

For the sake of clarity, a (exaggerated) convex curved surface curvature is shown.

In a further process step according to FIG. 1 c, a

Positioning of an embossing punch 4 above the mask material 3. Oer embossing punch 4 can be oriented and aligned in particular relative to the substrate 1 and / or relative to the seed layer 2. Alignment is preferably by means of alignment marks (not shown), if they are present. For unstructured substrates, however, it is preferable to use a purely mechanical one

Alignment performed.

In a further process step according to FIG

Mask material 3 is structured by the embossing punch 4 such that

Mask passages 1 1, preferably to the seed layer 2 reaching mask openings are formed. The diameter d of

Mask passages 1 1 is in particular less than 10 mm, preferably less than 1 mm, more preferably less than 100 μπι, on

most preferably less than 1 0 μπι, most preferably less than 1 μηι. The depth t of the mask passages 11 is in particular less than 100 μιτι, preferably less than 1 μιτι, more preferably less than 1 μιη, most preferably less than 100 nm, most preferably less than 10 nm

In particular, the ratio between the diameter d and the depth t is greater than 1, preferably greater than 10, more preferably greater than 100, most preferably greater than 200, most preferably greater than 300. The mask opening therefore preferably has a diameter d which is greater than or equal to the depth t.

In FIG. 1 e, a hardening of the mask material 3 is shown. The curing can be thermally and / or chemically and / or

electromagnetically. Curing preferably takes place electromagnetically, more preferably by means of UV light. The advantage of curing by means of electromagnetic radiation is the vanishingly small or practically negligible extent of the mask material 3, while a thermal

Curing can cause a non-negligible thermal expansion, which damage the structures and / or

could move.

FIG. 1 f represents a demolding step. After demolding, the mask 6 remains on the seed layer 2. Should the

Mask passages 1 1 of the mask 6 after removal of the

Embossing stamp 4 does not reach the germ layer 2, so one

Residue 12 be present, an additional etching step (see Figure l g) is performed. As a result of this etching step, the residual layer 12 is removed, in particular in the region of the mask passages 11, in order to expose the seed layer 2 in the region of the mask passages 11.

Preferably, the generation of the residual layer 12 is avoided in the embossing step by the embossing punch 4 to the seed layer 4th

approaches and displaces the mask material 3 in the area of the mask passages 1 1.

In a further process step according to FIG

Coating by a coating system 7, in particular at a high temperature. Before the coating therefore becomes a process chamber (not shown) in which the coating takes place. The coating gets a coating material! 8m, that

is preferably identical to the seed layer material of the seed layer 2, via a flow of material 8 through the mask passages 11 to the seed layer surface 2o of the seed layer 2. The coating material 8m crystallizes out on the seed layer surface 2o.

Due to the high temperature during coating 3 gases 1 3 come out of the mask material, which leads to a hardening of the

Mask material 3 lead. It is conceivable that the

Coating temperatures are not sufficient to expel the gases 13 from the mask material 3. In such a case, that will

Mask material 3 thermally treated before the overgrowth according to the invention until all the gases 13 are expelled from the mask material 3.

FIG. 11 shows a magnification of a not to scale

Area A (Figure l h) one of the mask passages 1 1 at a first time t l. The mask passage 1 1 has the feature size d. In the case of a radially symmetrical mask passage 1 1 d would be the

Diameter of the mask passage 1 1 parallel to the substrate surface l o. The coating material 8m is limited by the structure size d in terms of its nucleation on a part of the Kcimschichtobcrfläche 2o. The material deposition of the coating material 8m is preferably carried out epitaxially. That means that

Coating material 8m maintains the crystallographic orientation (hkl) of the seed material surface 2o during its growth. At this time, the growth of the coating material 8m starts in a nucleus plane K1 which coincides with the nucleus surface 2o of the seed layer 2. Figure lj shows a non-scale enlargement of the area A of a mask passage 1 1 at a second time t2. At this time, the coating material 8m has already grown to a height h1. A new (higher) germ layer K.2 has emerged at a distance from the original germ surface 2o. A characteristic feature is that the error density, in particular the

Dislocation density of dislocations 10 decreases with increasing distance to the original germ surface 2o. The upward-growing, in particular monocrystalline and / or epitaxial, layer becomes increasingly perfect as the distance from the original seed surface 2o increases.

FIG. 1 k shows the state of an overgrowth of the overgrowth layer 14 via the mask 6 at a third point in time t 3 at which a

Node level K3 is above the mask surface 6o. The

Coating material 8m has distributed over all mask openings 1 1, in particular evenly. The defect density, in particular the dislocation density of the dislocations 10, reaches a minimum and is preferably negligibly small. The process according to the invention thus produced a full-area, monocrystalline, in particular epitaxial and defect-free, layer 14.

FIG. 11 shows an end product 15 according to the invention, consisting of a substrate 1 and a new, in particular monocrystalline and / or epitaxial, preferably on an upper side 14o defect-free over-growth layer 14. The end product I S can be used as a starting point for further processing. Germ layer 2 and

Upper growth layer 14 can be distinguished from one another in particular by the defect density or dislocation density. The overgrowth layer 14 has the mask 6 preferably fully, preferably completely enclosed. With the process according to the invention, it is possible not only to produce a predominantly defect-free, monocrystalline and / or epitaxial layer that extends beyond the mask 6, but also a layer with enclosed structures, in particular dots. If the order of magnitude of these structures is in the nanometer range, this is called nanodots.

Such nanostructures are necessary to produce semiconductor devices with very specific, in particular based on quantum mechanical effects, properties. The nanodots are therefore the dots of the monocrystalline and / or epitaxial layer surrounded by the mask embossed according to the invention. Nanowires (nanowires) are a special case. Under appropriate conditions, these can be formed by a further growth of the monocrystalline and / or epitaxial layer from the aperture into the air. Therefore, the monocrystalline and / or epitaxial layer does not laterally unite to form a layer upon reaching the mask surface, but continues its growth unhindered normal to the mask surface.

Also conceivable is the exclusive use of the cultured, monocrystalline and / or epitaxial, in particular defect-free, upper growth layer 14 without the enclosed mask 6. In order to remove the mask 6 from the upper growth layer 14, the side with the less perfect seed layer 2 is preferably removed.

A processing of the upper growth layer 14 is conceivable, followed by a subsequent bonding step of a second substrate 1 'on the upper growth layer surface 14o according to FIG. After the bonding step has taken place, it is conceivable to remove the first substrate 1, followed by an etching and / or polishing and / or regrinding process by means of a grinding device 16 at least of parts of the seed layer 2 and / or parts of the overgrowth layer 14. It can

in particular, the complete mask 6 are removed. The removal of the substrate 1 is facilitated mainly by the

Seed layer 2 has a low adhesion to the substrate 1.

Particularly preferred would be a process flow in which a first

Back grinding and / or polishing of the invention produced

Upper growth layer 14 followed by an etching process. The final etching process serves on the one hand to reduce the stress and on the other hand to remove a defect layer produced by the slipping process.

FIG. 2 shows a further side view, not to scale, of an embodiment of an end product according to the invention, consisting of several nanowires 1 7 growing out of the mask passages 11. In contrast to other embodiments according to the invention, the nanowires 17 do not unite laterally to form an upper growth layer, but instead grow, in particular exclusively, upwards.

Method for applying an overgrowth layer to a seed layer B EZ U G S E C H E N L I S TE

1, r substrate

lo substrate surface

2 germ layer

2o germ layer surface

3 mask material

4 (embossing) stamp

5 stamp structure

5o stamp structure surface

6 mask

7 coating system

8 material flow

8m coating material

9 crystallographic plane (hkl)

10 lattice construction errors, in particular dislocation

11 mask passes

12 residual layer

13, 13 ⁴ gases

14 overgrowth layer

14o overgrowth layer surface

15 final product

16 grinder

17 nanowire

Kl, K2, K3 germline

hl, h2 height

t depth

d diameter

Claims

Method of applying an overgrowth layer to a seed layer P atentan sp ruch e

A method of applying a masked overgrowth layer (14) to a seed layer (2) for the manufacture of

Semiconductor devices, characterized in that a mask (6) for masking the overgrowth layer (14) is embossed on the seed layer (2).

2. The method of claim 1, wherein the seed layer (2) and / or the overgrowth layer (14) are formed epitaxially and / or monocrystalline lin, in particular from one or more of the following materials as the seed layer material and / or upper growth layer material:

3. Method according to claim 2, wherein identical materials are used as seed layer material and as overgrowth layer material.

4. The method according to at least one of the preceding claims, wherein the mask (6) consists of one, in particular one

Main component and a sub-component, masking material is embossed, preferably with one or more of the following main components:

• silsesquutoxane. in particular polyhedral oligomeric silsesquioxane (POSS) and / or

Polydimethylsiloxane (PDMS) and / or

Tetraethyl orthosilicate (TEOS) and / or

Poly (organo) siloxanes (silicone) and / or

Perfluoropolyether (PFPE).

5. The method of claim 4, wherein the mask material for masking the seed layer (2) is applied to the seed layer (2), in particular by means of one of the following methods:

Physical separation methods, in particular PVD,

and or

Chemical deposition processes, in particular CVD,

preferably PE-CVD, and / or

Wet-chemical deposition, and / or

• Belackung, in particular Schleuderbelackung or

Spray Coating.

6. The method according to at least one of the preceding claims, wherein the mask material for forming the mask by Imprintl ithography, preferably by means of

Nanoimprint lithography, structured.

7. The method according to at least one of the preceding claims, wherein the seed layer (2) after the application of the mask (6) in the not covered by the mask (6) coating area of the seed layer surface (2o) with the upper growth layer (14) is coated.

8. The method according to at least one of the preceding claims, wherein the overgrowth layer (14) over the mask (6) is applied out.

9. The method according to at least one of the preceding claims, wherein the seed layer (2) after application of the

Supernatant layer (14) at least partially removed, in particular ground, is.

10 final product (1 5), comprising:

- A seed layer (2) for the production of

Semiconductor devices,

A masked overgrowth layer (14) on the seed layer (2) with a lower dislocation density than the seed layer

(2).