DE10104258A1 - Applying structured layer to support substrate involves filling structured pattern substrate with filler, placing pattern on support, binding filler to support, and removing pattern so that filler remains bonded to support - Google Patents

Abstract

Applying a structured layer to a support substrate (101) involves filling a structured pattern substrate (102) corresponding to the structured layer with a filler; placing the pattern substrate on the support substrate; bonding so that the filler binds to the substrate; and removing the pattern substrate so that the filler remains bound to the support structure and the structured layer is formed on the support substrate. Preferred Features: The pattern substrate is printed on the support substrate. The pattern substrate is made from a material having a higher melting point than the filler and the material of the support substrate. The pattern substrate is made form silicon dioxide. A pattern substrate release layer is applied to the structured surface of the pattern layer.

Description

The invention relates to a method for applying a structured layer on a carrier substrate.

Such a method is known from [1].

In the method known from [1], a layer is applied to a carrier substrate, for example by means of

• - a separation process from the gas phase,
• - a vapor deposition process or also
• - a sputtering process.

The applied layer is by means of lithography structured, for example, by the structure to be structured Layer a photoresist layer is applied and one of the Structure-appropriate exposure of the photoresist layer is done and the photoresist layer is developed so that according to the structure to be formed or as a negative Pattern a corresponding part of the photoresist layer Will get removed. This is followed by a process in which the Areas of the layer to be structured are removed through which the photoresist layer was exposed. Such a method is, for example, an etching of the structuring layer, preferably a wet etching or Dry etching, in which the still existing photoresist layer serves as an etching mask.

Lithography is used in the production of microelectronic components, for example in

• - Storage installations
• - optical elements,  
• - biosensors or
• - micromachines
• - Generally in the manufacture of an element in which to define a pattern on a substrate that means a layer is to be structured.

Lithography technology has the particular disadvantage on that irradiating the layers with light and also the subsequent etching process to chemical changes in one leads chemically sensitive material.

Another disadvantage of this approach is there too see that it is complex and therefore expensive and especially with regard to a further improved resolution significant technological problems in the implementation raises.

Furthermore, from [2] the so-called "nanoimprint lithography" known.

With this type of lithography there are no light rays needed, which are blasted onto a photoresist layer.

In this known method, a pattern becomes clear by means of a stamp in the material to be structured, that is, the layer to be structured, pressed, different expressed, impressed.

The layer to be structured is in this case usually thermoplastic material where possible is, aspect ratios in the structure of <1 and one Resolution of up to 10 nm for the structure to be formed guarantee.

Another advantage of nanoimprint lithography is that Possibility to see that a large local area  in parallel by means of a reusable "stamp" can be edited.

This technology is superior to optical lithography particular benefit on being very simple feasible and therefore very inexpensive is compared with the electron beam / ion beam lithography process, which have a comparable resolution.

However, as indicated in [3], this approach shows in the event that as a "stamp", which in the following also is referred to as a sample substrate, for example silicon for indenting the structure in the thermoplastic polymer as a material to be structured, for example Polymethyl methacrylate (PMMA), some disadvantages.

Especially when structuring a larger area, that is, in the event that the pattern substrate is a relative large spatial extent, defects are often in of the structured layer.

Another disadvantage of the method described in [2] is to be seen in that before pressing the pattern substrate into the PMMA layer to be structured, generally from a corresponding polymer, the polymer structure by means of Heating is liquefied and when the pressure is exerted means when the sample substrate is pressed into the liquid structuring layer of polymers the polymers through the channels formed by the structure in the pattern substrate cannot drain off easily. The one through the Displacement of the polymer material caused flow of Polymer material through the thin channels of the structure of the Pattern substrates often lead to blockages, which in the Furthermore to an incorrect structuring in the structuring layer.  

Problems in the outflow of displaced polymer material during Pressing the sample substrate into the liquid polymer in the liquid polymer layer occur particularly in the Edge areas of the pattern substrate in which a uniform pressure is no longer guaranteed.

The invention is based on the problem of a method for Applying a structuring layer on a Specify carrier substrate, which at least part of the Disadvantages of the known technologies described above reduced.

The problem is caused by the method of applying one structuring layer on a carrier substrate with the Features solved according to the independent claim.

In a method for applying a structure Layer on a carrier substrate becomes a structured Sample substrate provided. The structured Pattern substrate is according to the one to be structured Structured layer structured, that is, vividly, it points to the "pattern" of the layer to be structured inverse structure. The structured pattern substrate is filled with a filler. The pattern substrate is then placed on the carrier substrate and it becomes a Binding process carried out by means of which the filling material is attached is bound to the carrier substrate. In a final step the pattern substrate is filled with the filler and the Carrier substrate removed so that the filler on the Carrier substrate remains bound.

The invention makes it possible to on the carrier substrate and / or on a part of the layer to be structured, a apply structured layer on a carrier substrate, without having to apply pressure.  

In this way, the disadvantages of the known Nanoimprint lithography avoided because there are no defects due to drainage defects, such as blockages etc. in the channels of the pressed-in pattern substrate occur.

This clearly means that there are no defects in the structured layer due to displacement defects of displaced material of the layer to be structured occur.

The procedure is also very simple and therefore inexpensive and with very high accuracy.

Preferred developments of the invention result from the dependent claims.

To improve the bond between the filler and the carrier substrate or one described below the bonding layer applied to the carrier substrate can do this Pattern substrate are pressed onto the carrier substrate, wherein however, it should be noted that there is no structure created by the Pattern substrate is specified in the carrier substrate or in the bond layer is shaped, but only the pressure serves the bond between the filler and the To improve carrier substrate or the binding layer.

Thus, one is enough compared to the well-known nanoimprint Lithography significantly, reduced print to just one to achieve a very good binding effect.

According to a further embodiment of the invention, it is provided the filling material and / or the carrier substrate or the binding layer described in the following heat that the respective material at least partially in brought a liquid state and thus the free  Molecules of the liquid material of an improved bond subject.

This embodiment of the invention increases efficiency the procedure further increased.

Furthermore, the pattern substrate can be made of one material be produced, which has a higher melting point as the filler material and / or as the carrier substrate material or as the material used for the bonding layer.

According to one embodiment of the invention, the filling material brought into contact with the carrier substrate and by means of the Binding process is the filler material directly with the Carrier substrate bonded.

In other words, the filling material can be used directly with the The material of the carrier substrate reacts and binds.

The binding can for example

• - by means of covalent bonding,
• - by means of the Waal forces or
• - by means of ion binding,

respectively.

The binding options given above can also occur side by side.

According to an alternative embodiment, the Invention on the carrier substrate a bonding layer be applied and the filling material with the Binding layer are brought into contact. By means of the According to this embodiment, the binding process is the Invention the filler with the bond layer in bond brought.  

According to this embodiment of the invention, it can be provided be the same material for the bond layer as for the filler.

In this way, it becomes vividly possible on the Carrier substrate a first part of the to be structured Apply layer and into the structure of the pattern substrate to introduce a second part and clearly Heating the layer to be structured on the Form carrier substrate by the two sub-layers the same material in physical contact and to be bound.

The pattern substrate can be made of silicon with or without one oxidized surface.

Furthermore, by means of a chemical Preprocessing step on the structured surface of the pattern substrate is a pattern substrate release layer are applied, the material of the sample substrate Release layer is chosen such that the bond between the pattern substrate release layer and the filler is less than the degree of binding between the filling material and the binding layer or between the filling material and the carrier substrate.

This will remove the pattern substrate from the Filling material facilitates and thus the generation of Defects in the structured layer are further reduced. In In this case, the filler material is placed on the sample substrate. Release layer applied.

The pattern substrate release layer is preferably as monomolecular layer on the structured surface of the Sample substrate applied.  

The pattern substrate release layer can be made from one of the following materials:

• - propyltrichlorosilane,
• - a material of the class n-decyltrichlorosilane, in particular
• - dodecyltrichlorosilane.

The filling material can in principle by any Process introduced into the structure of the pattern substrate, for example, are filled in, for example by means of an evaporation process or a sputtering process. According to one embodiment of the invention, the filling material can be a resin, preferably polymethyl methacrylate (PMMA) or Polymethyl methacrylate MA (PMMA MA) can be used.

Due to its material properties, PMMA is suitable for use in the process is very good and is also very good available inexpensively.

The resin can be spin coated (Spin coating) filled in the structure of the sample substrate become.

Alternatively, a metal can be used as filler material, for example

• - Gold,
• - Silver,
• - copper,
• - Nickel,
• - Titan,
• - Cobalt,
• - Chrome,
• - manganese,
• - iron,
• - platinum,
• - palladium, or  
• - An alloy of at least one of the aforementioned Metals.

The metal can be electroplated into the structure of the Sample substrates are filled.

Furthermore, according to another embodiment of the invention, a dielectric material can be used, for example

• - silicon dioxide,
• - silicon nitride,
• - titanium oxide, or
• - a polymer with an oxidized surface.

Furthermore, the pattern substrate can be made of silicon. According to another development of the invention, it is provided the exposed surface of the in the structure of the sample substrate filled before the Binding process to polish, creating another Improve the binding properties between the Filling material and the carrier substrate or the binding layer is achieved.

For example, a chemical-mechanical one can be used for polishing Polishing process (CMP process) can be used.

The structured layer and thus the filling material can have a plurality of layers placed one on top of the other, which in the structure of the pattern substrate preferably in successive process steps are introduced.

A, preferably molecular, Adhesive layer applied to the adhesion of the carrier substrate with the fill material to increase.  

Alternatively, the surface of the carrier substrate can be such be chemically treated that the liability of the Carrier substrate with the filling material is increased.

The invention is particularly suitable for manufacturing

• - a hard disk storage with magnetic nanopoints,
• - a photonic crystal,
• - An integrated circuit as a replacement for one complex lithography process,
• - a microsensor, or
• - a micromachine.

The method can also be used generally for Manufacture of microstructures and nanostructures with Applications in all areas of microelectronics, in the Areas of data storage, optical elements in which Area of optoelectronics, biosensors and Micromachines.

Embodiments of the invention are in the figures are shown and are explained in more detail below.

Show it

FIG. 1a to 1d, the manufacturing process for producing a carrier substrate with a patterned layer in its individual process steps according to a first embodiment of the invention;

Figures 2a to 2d the manufacturing process for producing a carrier substrate with a patterned layer in its individual process steps according to a second embodiment of the invention.

First embodiment

FIG. 1 a shows a carrier substrate 101 made of silicon and a pattern substrate 102 made of silicon.

The pattern substrate 102 made of silicon is structured by means of electron beam lithography in such a way that it has an inverse structure with correspondingly inversely shaped depressions 103 , compared to the structure to be formed in the structured layer to be applied.

In other words, valleys in the layer to be structured to be applied correspond to elevations in the pattern substrate 102 .

The pattern substrate 102 is thus formed by means of electron beam lithography.

The surface 104 of the pattern substrate 102 is oxidized in two preprocessing steps and coated with a monomolecular layer 105 made of, for example, dodecyltrichlorosilane, as the pattern substrate release layer.

The pattern substrate release layer is selected such that the material with the filler, ie the material of the second sub-layer 107, has a weaker bond than the second sub-layer 107 with the first sub-layer 106 after the bond between the sub-layers 106 , 107 has taken place.

The sample substrate release layer made of dodecyltrichlorosilane is applied by a one percent solution of the Dodecyltrichlorosilane in Tuloen on the oxidized and with OH terminated pattern substrate release layer is applied.

As shown in FIG. 1b, a first partial layer 106 made of polymethyl methacrylate (PMMA) is applied to the carrier substrate 101 by means of a rotary coating process.

Alternatively, polyethylene methacrylate can also be used as filler material (PEMA) or polyisobutyl methacrylate (PiBMA) can be used.

An adhesive adhesive layer 109 can optionally be provided between the carrier substrate 101 and the carrier substrate.

Alternatively, likewise optionally, the carrier substrate 101 can be chemically treated in such a way that the adhesion between the filling material and the carrier substrate 101 is increased.

A second partial layer, also made of PMMA 107 , is likewise applied to the structured side of the pattern substrate 102 , that is to say to the layer made of dodecyltrichlorosilane 105 , in such a way that at least part of the second partial layer projects beyond the structure of the pattern substrate 102 .

According to this embodiment, PMMA 950 K is used as a two to three percent solution in chlorobenzene.

The application takes place in such a way that the solution is preferably baked several times in succession on a hot plate and, according to one exemplary embodiment of the invention, is applied to one another in multiple individual partial layers, so that the second partial layer 107 is formed.

A rotary Coating process used.

In a further step (cf. FIG. 1c), the carrier substrate 101 and the pattern substrate 102 are placed on top of one another in such a way that the exposed surface 108 of the first sub-layer 106 and the exposed surface 109 of the second sub-layer 107 come to lie on one another and thus physically with one another Be brought in contact.

In a further step, the resulting system is now heated so that the second sub-layer 107 made of the filler material and the first sub-layer 106 become liquid and are chemically bonded to one another.

The partial layers 106 , 107 are heated up to a temperature above their glass transition temperature, according to this exemplary embodiment to a temperature T of
T = glass temperature Tg + 70 ° C ± a tolerance of approximately 20 ° C.

The usual glass transition temperature Tg for PMMA is in a range between 100 ° C and 130 ° C.

To improve the physical connection, a pressure in a range from 50 bar to 100 bar is exerted on the sample substrate 102 in the direction of the carrier substrate 101 .

In this connection, it is advantageously to be ensured that the compressive force on the pattern substrate 102 is directed in a straight direction perpendicularly to the surface of the carrier substrate 101 or the first partial layer 106 and is exerted uniformly over the entire pattern substrate 102 .

This can be done, for example, by using larger plates which are designed in accordance with the pattern substrate 102 .

The total element shown in FIG. 1c is heated to the temperature shown above for a period of 10 minutes to 30 minutes in order to achieve a homogeneous and complete bond between the molecules on the surface 108 of the first partial layer 106 and the surface 109 of the second partial layer 107 to ensure.

It was found that by gradually increasing the pressure exerted on the sample substrate 102 by 10 bar to 20 bar each to the final pressure of 100 bar to 150 bar with an increase of 10 bar per minute to a very even pattern along the entire Surface leads in the pattern substrate 102 and thus in the second sub-layer 107 .

These prerequisites are advantageously ensured, for example, by designing the surface of both the carrier substrate and the pattern substrate 102 as evenly and evenly as possible, and likewise the exposed surfaces 108 , 109 of the two sub-layers 106 , 107 .

In a further step, the system is cooled again, so that the two sub-layers 106 , 107 revert to the solid state.

In a final step (see. Fig. 1d), the patterned substrate 102 is removed from the support substrate 101 and the second sub-layer 107 with the corresponding desired pattern remains because of the higher bonding force between the two partial layers 106, 107 compared with the bonding forces between the second partial layer 107 and the surface of the pattern binding layer 105 on the carrier substrate 101 and thus forms the desired structured layer 108 together with the first partial layer 106 .

Alternatively, the pattern substrate 102 can also be produced by means of conventional optical lithography processes and so-called lift-off technology.

Second embodiment

The second embodiment is similar in its method steps of the method according to the first process example, very, and therefore, like elements in FIGS. 2a through Fig. 2d are provided with the same reference numerals as the elements according to the first embodiment.

In contrast to the method according to the first exemplary embodiment, according to the second exemplary embodiment only a layer 107 of PMMA or PMMA MA is introduced as filler material into the pattern substrate 102 in the manner described above according to the first exemplary embodiment.

No partial layer made of the filling material, that is to say made of PMMA, is applied to the carrier substrate 101 , but rather an adhesive adhesive layer 201 which is used only for fastening, that is to say gluing, the layer of PMMA 107 to the carrier substrate 101 .

The adhesive adhesive layer 201 preferably has the following materials:

• - a hardenable two-component system Polydimethylsiloxane (PDMS), or
• - an epoxy based adhesive.

The further process steps are essentially identical to the method according to the first Embodiment and for this reason are not here explained further.

It should only be noted that there is a chemical bond between the layer made of PMMA 107 and the adhesive adhesive layer 201 and not between two partial layers 106 , 107 made of the same material as in the first exemplary embodiment.

Third embodiment

According to a third embodiment of the invention it is provided instead of a thermoplastic polymer such as for example PMMA a thermally curable polymer, for example PDMS, preferably prepolymer from PDMS in liquid state in the structure of the pattern substrate fill and then harden or polymerize, to bring them into contact with an adhesive adhesive layer, which is applied to the carrier substrate, and then harden the PDMS.

In the method according to the third embodiment a thin layer of PDMS is formed on the pattern substrate. Then the prepolymer is cured and finally by means of an adhesive adhesive layer, for example an epoxy based adhesive layer, bonded to the substrate.  

LIST OF REFERENCE NUMBERS

101

carrier substrate

102

patterned substrate

103

deepening

104

Surface structured pattern substrate

105

Patterned substrate release layer

106

First sub-layer

107

Second sub-layer

108

Exposed surface of the first sub-layer

109

Exposed surface of the second sub-layer

201

adhesive layer

Claims (29)

1. Method for applying a structured layer on a carrier substrate,
in which a structured pattern substrate, which is structured in accordance with the structured layer, is filled with a filling material,
in which the pattern substrate is placed on the carrier substrate,
in which a binding process is carried out by means of which the filler material is bound to the carrier substrate,
in which the pattern substrate is removed in such a way that the filler material remains bound to the carrier substrate, as a result of which the structured layer is formed on the carrier substrate. 2. The method according to claim 1, in which the pattern substrate is pressed onto the carrier substrate becomes. 3. The method according to claim 1 or 2, in which in the binding process the filler and / or the Carrier substrate is / are heated so that the binding of the Filling material is carried out on the carrier substrate such that the Filling material at least partially in a liquid state brought. 4. The method according to claim 3, in which the pattern substrate is made of one material which has a higher melting point than that Filling material and as the carrier substrate material. 5. The method according to any one of claims 1 to 4,
in which the filling material is brought into contact with the carrier substrate, and
in which the filling material is directly bonded to the carrier substrate by means of the binding process. 6. The method according to any one of claims 1 to 4,
in which a binding layer is applied to the carrier substrate, and
in which the filling material is brought into contact with the binding layer, and
in which the filling material is bonded to the binding layer by means of the binding process. 7. The method according to claim 6, in which the binding layer has the same material as the filling material. 8. The method according to any one of claims 1 to 7, wherein the bond between the filler and the carrier substrate or between the filler and the binding layer is carried out by means of
covalent bonds, and / or
von der Waalscher forces, and / or
Ionic bonds. 9. The method according to any one of claims 1 to 8, where the sample substrate is made of silicon dioxide is. 10. The method according to any one of claims 1 to 9,
in which a pattern substrate release layer is applied to the structured surface of the pattern substrate, and
in which the filler material is applied to the pattern substrate release layer. 11. The method according to claim 10,  in which the pattern substrate release layer as a monomolecular Layer on the textured surface of the pattern substrate is applied. 12. The method of claim 10 or 11, wherein the pattern substrate release layer is made of one of the following materials:

• Propyltrichlorosilane,
• - a material of the class n-decyltrichlorosilane, in particular
• - dodecyltrichlorosilane.

13. The method according to any one of claims 1 to 12, in which the filling material by means of an evaporation process or by means of a sputtering process into the structure of the Pattern substrate is introduced. 14. The method according to any one of claims 1 to 13, in which a resin is used as filler. 15. The method according to claim 14, in which polymethyl methacrylate or Polymethyl methacrylate MA is used. 16. The method according to claim 14 or 15, where the resin is spin coated into the structure of the pattern substrate is filled. 17. The method according to any one of claims 1 to 13, where a metal is used as filler. 18. The method according to claim 17, wherein one of the following metals is used as filler:

• - Gold,
• - silver,
• - copper,
• - nickel,
• - titanium,
• - cobalt,
• - chrome,
• - manganese,
• - iron,
• - platinum,
• - palladium, or
• - An alloy of at least one of the aforementioned metals.

19. The method according to claim 17 or 18, where the metal is electroplated into the structure of the pattern substrate is filled. 20. The method according to any one of claims 1 to 13, in which a dielectric material is used as the filling material is used. 21. The method according to claim 20, in which one of the following dielectric materials is used as filler material:

• - silicon dioxide,
• - silicon nitride,
• - titanium oxide, or
• - a polymer with an oxidized surface.

22. The method according to any one of claims 1 to 21, in which the pattern substrate has silicon. 23. The method according to claim 22, in which the pattern substrate silicon with an oxidized Surface. 24. The method according to any one of claims 1 to 23,  where the exposed surface of the structure Sample substrate filled filler before the Binding process is polished. 25. The method according to claim 24, in which the polishing by means of a chemical-mechanical Polishing process is carried out. 26. The method according to any one of claims 1 to 25, in which the structured layer has a plurality of one another applied layers, which in the structure of the Sample substrates are filled. 27. The method according to any one of claims 1 to 26, with a molecular adhesive layer on the carrier substrate applied to the adhesion of the carrier substrate with to increase the fill material. 28. The method according to any one of claims 1 to 27, in which the surface of the carrier substrate is so chemical is treated that the liability of the carrier substrate with the Filling material is increased. 29. The method according to any one of claims 1 to 28, used to produce one of the following elements:

• - a hard disk storage with magnetic nanopoints,
• - a photonic crystal,
• - an integrated circuit,
• - a microsensor, or
• - a micromachine.