SE543189C2 - Device with a waveguide supported on a substrate and method for its fabrication - Google Patents

Abstract

A device (1) is described which comprises a device layer (4), and a substrate (2) defining a substrate plane (3). The device (1) also comprises a waveguide (7) for guiding an electromagnetic wave, the waveguide extending in a length direction (L) in the device layer (4), the waveguide (7) having a width (w) and a height (h). The device (1) also comprises a support structure (6) comprising a polymer layer (18). A comparison cross section (25) is parallel to the substrate plane (3), extends through the polymer layer (18) at a spacing (y) perpendicularly from the substrate plane (3), and extends perpendicularly to the length direction (L) to a breadth (x), equal to the width (w) of the waveguide. The spacing (y) is chosen to maximize a ratio (r) of the area of the polymer layer to the area of the support structure (6) within the comparison cross section (25), and the ratio (r) is at least 50%. A method for fabrication of such a device (1) is also described.

Description

Device With a Waveguide supported on a substrate and method for its fabricationTechnical field The invention relates to a device with a waveguide supported by a support structure and to a method for fabrication of such a device.

Background Optical sensing using the absorption bands of various gases in the visible or infrared (IR)wavelength range is an established method. The absorption may be measured in cavities withmirrors, in order to achieve an effective interaction length which is longer than the physicalsize of the cavity. This approach is limited by the optical losses in the mirrors. For IR, thesource is often a broadband incandescent lamp. To get a spectral resolution, optical spectral analysis is then needed. Detectors can be thermal or semiconductor-based photon detectors.

To make sensitive devices with a long optical path-length, either high quality mirrors must beused or the physical path, and hence the device size, must be long. For many applications, low gas flows and the large volume of the gas chamber limit the response speed of the sensor.

WO 2017/ 003353 describes a sensor device for detecting a component in a fluid such as agas. The sensor device comprises a planar substrate, a waveguide for guiding an electro-magnetic wave and a support structure extending from the substrate to the waveguide. Amethod for detecting a component in a gas comprises the steps of providing the waveguide incontact with the gas, transmitting an electromagnetic wave into a first portion of thewaveguide, allowing the electromagnetic wave to interact with the fluid in a region of anevanescent wave of the electromagnetic wave around the waveguide and detecting theelectromagnetic wave at a second portion of the waveguide. The component in the gas isdeterrnined based on the detected electromagnetic wave at the second portion. The width ofthe support structure varies along the length direction of the waveguide and the waveguide isof a material of a first composition and the support structure is of a material of a secondcomposition. In this way, the influence of the support structure on the waveguiding propertiesis decreased. In order to minimize the influence of the support structure on the waveguidingproperties and to increase the sensitivity of the sensor device it is advantageous to have the waveguide partly free-hanging.

It is desirable to provide gas sensors for mid-IR wavelengths. However, it is difficult to fabricate efficient gas sensors of the above described type with waveguides. This is partly due to the problems with leakage of optical energy from the waveguides into the substrate, and also due to lack of substrates with suitable materials and dimensions.

Apart from a light source and a detector it might also be desirable to include electronics for driving of the light source and electronics for readout from the detector.

Apart from a sensor device, also other devices may be contemplated which comprise anelongated structure extending in a length direction in a device layer and being supported on afirst layer by a support structure.

One possible approach for fabricating a sensor device as is described in WO 2017/003353 isto use an SOI (silicon on insulator) wafer as starting material so that the base layer is a siliconlayer, the interrnediate layer is a silicon dioxide layer and the device layer is a silicon layer.Such wafers are readily available which is advantageous. The silicon dioxide layer in such adevice is commonly known as a BOX (buried oxide) layer. A problem, however, with usingSOI as starting material is that there will be inherent stresses in the device layer in SOIwafers. The problem with inherent stresses increases with increasing thicknesses of the BOXlayer and decreasing thickness of the device layer. This puts a limit on the possible thicknesscombinations that can be produced and, hence, are available. Stresses in the device layer alsocause the waveguides to bend. If the waveguides bend downwards, they get closer to the baselayer and this increases the losses. A thick oxide layer would be desirable to achieve a largeseparation distance between the waveguide and the base layer. A large separation distancebetween the waveguide and the base layer is advantageous to minimize the losses in the waveguide.

For gas sensing it would be advantageous to use wavelengths in the mid-IR wavelength range,i.e. the wavelength range of 3-10 um. In order to fabricate a gas sensor for this wavelengthsensor it is necessary to provide a waveguide with low losses in said wavelength region. It ishowever very difficult to fabricate a waveguide with low losses in said wavelength range withprior art methods. This is partly due to lack of availability of suitable substrates in terms of materials and dimension.

Summarv of the invention An object of the present invention is to provide a device and a method for its fabrication,which device comprises a waveguide, supported on a substrate, for guiding anelectromagnetic wave, with which device at least one of the problems with the prior art is alleviated.

Another object of the present invention is to provide a device and a method for its fabrication,Which device comprises a Waveguide supported on a substrate, Which Waveguide is arrangedfor guiding an electromagnetic Wave, With Which device the problem of the prior art With mechanical stresses in the device layer is alleviated.

Another object of the present invention is to provide a device and a method for its fabrication,Which device comprises a Waveguide supported on a substrate, Which Waveguide is arrangedfor guiding an electromagnetic Wave, With Which device the problem With losses ofelectromagnetic energy from the Waveguide is at least alleviated, especially for Wavelengths in the mid-IR range, i.e., especially in the Wavelength range from 3-10 um.

At least one of these objects is provided With a device according to the independent device claim and a method according to the independent method claim.Further advantages are provided With the features of the dependent claims.

According to a first aspect of the present invention a device is provided comprising a devicelayer, a substrate def1ning a substrate plane extending through the point of the substrate beingclosest to the device layer. The device also comprises a Waveguide for guiding anelectromagnetic Wave. The Waveguide extends in a length direction L in the device layer, hasa Width W in the device layer plane in a direction perpendicular to the length direction L, and aheight h out of the device layer plane in a direction perpendicular to the length direction. Thedevice also comprises a support structure, Wherein the support structure extends from thesubstrate to the device layer to support the Waveguide on the substrate. A device layer planeextends parallelly to the substrate plane through the point of the device layer being supportedvia the support structure that is closest to the substrate plane. The device according to the firstaspect of the invention is characterized in that the device layer is of a different material than apolymer, and that the support structure comprises a polymer layer. A comparison crosssection extends, parallel to the substrate plane, through the polymer layer at a spacing yperpendicularly from the substrate plane and extends perpendicularly to the length direction Lto a breadth x, equal to the Width W of the Waveguide, from a side of the support structurebeing closest to the Waveguide. The spacing y is chosen to maximize a ratio r of the area ofthe polymer layer Within the comparison cross section to the area of the support structure Within the comparison cross section. The ratio r is at least 0.5.

The support structure extends along the length direction of the Waveguide. The Waveguide may have a curved shape such that the length direction fo lloWs the direction of the waveguide. There might be waveguide branches. The support structures do not have to be elongated nor parallel to the waveguide.

With a device according to the f1rst aspect the problem with mechanical stresses in thewaveguide is at least alleviated. This is due to the polymer layer, which allows the device, andthus the waveguide, to be very thin while the polymer layer may be thick without i11ducing significant stresses in the device layer.

Furthermore, with a device according to the f1rst aspect the problem with losses from thewaveguide is at least alleviated. The polymer layer decrease losses in the waveguide due toreduced absorption. At the same time, the waveguide may be thin. Thus, a large part of theelectromagnetic f1eld is outside the waveguide, i.e., the evanescent f1eld is outside the waveguide. This combination of properties is optimal for sensing application using IR light.

The device layer may be essentially parallel to the substrate plane. The device is preferablyproduced using standard microfabrication techniques, which will result in the device layerplane being essentially parallel to the substrate plane. However, after removal of materialbetween the device layer and the substrate the device layer may become slightly waved due tointemal stresses in the device layer. Thus, in the final device the device layer might not beperfectly parallel to the substrate plane. Also, the support structure will have essentially thesame desired height in all positions in which the device layer is supported. However, thesupport structure might still have small variations in height in different positions in which thedevice layer is supported. If the support structure has the same height in all points in which itsupports the device layer the device layer plane will extend parallelly to the substrate plane through all points of the device layer being supported via the support structure.

As specif1ed above the device layer plane extends parallelly to the substrate plane through thepoint of the device layer being supported via the support structure that is closest to thesubstrate plane. Thus, the device layer may be closer to the substrate plane between the pointsof the device layer being supported via the support structure. With regard to the substrate it isnorrnally flat before micro fabrication processing. However, during processing material may be removed from the substrate resulting in a surface of the substrate which is not perfectlyflat.

The polymer layer may be in contact with the device layer. Such an arrangement minimizesthe losses from the waveguide. However, it is also possible to have an additional layer between the polymer layer and the device layer/waveguide.

The ratio r of the area of the polymer layer within the comparison cross section to the area ofthe support structure within the comparison cross section is at least 0.5 as stated above.However, in order to minimize the losses from the waveguide the ratio r is at least 0.80, preferably at least 0.90 and most preferred 0.95.

Another important feature for minimizing the losses from the waveguide is to have a largedistance D2 perpendicular to the substrate plane, between the device layer plane, and thus alsothe waveguide, and the substrate plane. The distance D2 may be as small as 5 nm. However,in order to minimize the losses from the waveguide, the distance D2 may be at least 2 um,preferably at least 3 um, more preferably at least 4 um, more preferably at least 6 um, andmost preferably 10 um. It has not been possible to achieve such distances perpendicular to thesubstrate plane, between the device layer plane and the substrate plane in the prior art withoutlarge mechanical stresses in the device layer. However, by introducing the polymer layer it is possible to increase the distance.

The maximum distance Dl, perpendicular to the substrate plane, consisting of free-spacebetween the waveguide and any solid material below the waveguide can be zero according tothe invention. This means that the waveguide supported by material over its entire surfacefacing the substrate. However, in order to minimize losses from the waveguide the ratiobetween the maximum distance Dl, perpendicular to the substrate plane, consisting of free-space between the waveguide and any solid material below the waveguide, and the waveguideheight h may be >6, preferably >8, most preferred >l0. A large ratio between the maximumdistance Dl, perpendicular to the substrate plane, consisting of free-space between thewaveguide and any solid material below the waveguide, and the waveguide height h may beachieved by having a thick polymer layer and/or a thin device layer. It may however also be achieved by removal of material from the substrate.

The device layer may comprise a substructure, comprising at least one subelement, arrangedat a distance from the waveguide, wherein the waveguide is connected to the substructurewith connection means in the device layer, and wherein the support structure extends from thesubstrate to the substructure. By having a substructure as specified above the side of thewaveguide facing the substrate may be completely free from material which minimizes thelosses through this side of the waveguide. However, in order to provide suspension of the waveguide, connection means have to be provided in the device layer.

The connection means may be in the form of a membrane extending along each side of thewaveguide, wherein the membrane has a height being no more than 98 % of the height of the waveguide, preferably no more than 95 % of the height of the waveguide, and most preferred no more than 80% of the height of the Waveguide. The difference in height between theWaveguide and the membrane is suff1cient to confme the electromagnetic Wave in theWaveguide. A membrane is quite easy to produce and provides an even support for theWaveguide. Due to the fabrication process of a membrane, the membrane might contain holes Which are necessary if material needs to be removed undemeath by under etching.

The substructure may comprise a plurality of subelements. By having the substructure dividedin a plurality of subelements the losses of electromagnetic energy from the Waveguide may befurther reduced. Another benefit from having subelements is that the footprint of the substructure is minimized. Thus, area is made free for other components.

The support structure may comprise a plurality of support elements extending from thesubstructure. By having the support structure divided into a plurality of support elements thelosses of electromagnetic energy from the Waveguide is minimized further. Depending on thearrangement of the device the device may or may not comprise additional layers on top of the substrate Which form part of the support structure.

Each support element may extend from a subelement to the substrate. This arrangement of thesupport elements further reduces the losses from the Waveguide. Another advantage is that the footprint of the support element is minimized.

The connection means may comprise a plurality of bridges connecting the Waveguide With thesubstructure. By having the connection means divided in a plurality of bridges the losses ofelectromagnetic energy through the connection means is minimized. The bridges may have asmaller height than the Waveguide to further enhance the confinement of the electromagnetic Wave in the Waveguide and to thereby reduce the losses.

The ratio of the distance D3 between the support structure and the Waveguide to the width Wof the Waveguide is 0.5-100, preferably 1-10, and most preferred 2-5. With the ratio in saidintervals the losses from the Waveguide are minimized. Even if said ratio may be as high as100 it is favorable to have said ratio beloW 10 in order to minimize the space for the Waveguide and support structure, and to increase mechanical stability of the device.

The support structure may extend from the substrate to the Waveguide. This is an altemativeto having the Waveguide suspended in substructures. The advantages of having this structure is simplif1ed fabrication and minimized footprint area.

When the support structure extends from the substrate to the Waveguide the ratio r of the area of the polymer layer Within the comparison cross section to the area of the support structure within the comparison cross section may be at least 0.95, preferably at least 0.98, and mostpreferred at least 0.99. The losses from the waveguide is more sensitive to the material in thesupport structure when the support structure extends from the substrate to the waveguideinstead of to the subelements.

The polymer layer may extend over the entire cross section area of the support structure in thecomparison cross section. In this way the losses are minimized compared to the case of having metal extending from the waveguide.

The width of the support structure at the point of support of the waveguide may be smallerthan the width W of the waveguide. In order to minimize losses of electromagnetic energyfrom the waveguide through the support structure the contact area between the support structure and the waveguide should be minimized.

The support structure may comprise a plurality of support elements such that the waveguide isfree-hanging between two adj acent support elements. This fiarther reduces the contact areabetween the support structure and the waveguide and thus minimizes the losses of electromagnetic energy through the support structure.

At least one of the support elements may be made entirely of a polymer. This further reducesthe losses from the waveguide. A support element made entirely of polymer may be formed from a polymer layer between the device layer and the substrate.

The width w of the waveguide may at least 5 times the height of the waveguide. Theevanescent field becomes stronger if one of the height and the width of the waveguide is madesmaller than the wavelength. This is advantageous if the device is to be used as, e.g., a gassensor. Furthermore, when fabricating a waveguide, the top and bottom surfaces can be madevery smooth while the sides surface will have a higher roughness than the top and bottomsides. A higher roughness will result in higher losses per surface area. By making the sidesurfaces smaller than the top and bottom surfaces the losses may be minimized while stillretaining the waveguiding properties of the waveguide. Thus, it is very favourable to have a width to height ratio of more than 5 in order to minimize the losses.

The height of the waveguide may be smaller than the wavelength of the electromagnetic waveto be guided. This is advantageous in order to control the modes of the electromagnetic wavein the waveguide properly. With the height of the waveguide being smaller than thewavelength of the electromagnetic wave to be guided the modes of the electromagnetic wavemay become loosely confined, which is advantageous it the device is to be used for, e. g., gas sensing.

The Waveguide may be arranged for guiding an electromagnetic Wave With a WavelengthWithin the range of 0.4-100 pm, preferably 1.2-20 pm, and most preferred Within 3-12 pm.

These Wavelengths are useful When the device is to be used as a gas sensor.

The thickness of the polymer contact layer may be 5 nm to 100 pm, preferably 200 nm to 50pm, and most preferably 3-20 pm. The loW part of the first interval requires the supportstructure to be constituted by other materials apart from the polymer contact layer(s). In orderto provide a reliable polymer contact layer(s) the thickness of the polymer contact layer(s) ispreferably 200 nm - 50 pm, most preferably 3-20 pm.

The support structure may comprise conductive material extending from the device layer tothe substrate. The extension of the conductive material from the substructure depends onWhere the active devices and metal lines are situated. By having a conductive materialextending from the substrate to the substructure electrical connection between the device layerand the substrate is enabled. This, may be useful for example When active devices are arranged on or in the device layer and are to be connected to devices in or on the substrate.

The device may comprise metal lines and/or active devices, such as transistors, light sourcesand detectors, in or in contact With the device layer and/or the substrate. This enablesintegration of suspended Waveguides on top of preprocessed Wafers With e.g. CMOS circuits for readout/control of source and detectors.

According to a second aspect of the present invention a method for fabrication of a device isprovided. The device comprises a device layer, a substrate defining a substrate planeextending through the point of the substrate being closest to the device layer. The device alsocomprises a Waveguide for guiding an electromagnetic Wave, the Waveguide extending in alength direction L in the device layer, the Waveguide having a Width W in the device layerplane in a direction perpendicular to the length direction L, and a height h out of the devicelayer plane in a direction perpendicular to the length direction. The device also comprises asupport structure, Which extends from the substrate to the device layer to support theWaveguide on the substrate. A device layer plane extends parallelly to the substrate planethrough the point of the device layer being supported via the support structure that is closestto the substrate plane. The method comprises the steps of providing a handling substrate onWhich a device layer is arranged, the handling substrate and the device layer forrning a devicelayer assembly, providing a substrate, providing a polymer contact layer on the substrateand/or on the device layer assembly, on the same side of the handling substrate as the devicelayer. The method also comprises the steps of attaching the device layer assembly on the substrate With the device layer arranged between the handling substrate and the substrate, so that the polymer contact layer(s) form the polymer layer, removing the handling substrateafter attachment of the device layer assembly to the substrate, removing material from thedevice layer to form the waveguide, and removing material from the polymer contact layer(s)to form the support structure. The device layer is of a different material than a polymer. Thesupport structure comprises a polymer layer. A comparison cross section extends, parallel tothe substrate plane, through the polymer layer at a spacing y perpendicularly from thesubstrate plane and extends perpendicularly to the length direction L to a breadth x, equal tothe width W of the waveguide, from a side of the support structure being clo sest to thewaveguide. The spacing y is chosen to maximize a ratio r of the area of the polymer layerwithin the comparison cross section to the area of the support structure within the comparisoncross section. The ratio r is at least 0.5.

The method of using a sacrif1cial wafer as in the method according to the second aspect of theinvention is known per se from US 7067345, which is hereby included by reference in thisapplication.

The method according to the second aspect of the invention makes it possible to providesuspended waveguides on top of preprocessed wafers with, e. g., CMOS circuits forreadout/ control of source and detectors. The method according to the second aspect alsoprovides a favourable method of fabricating a device according to the first aspect of the present invention.

The process step to release the waveguide from the support structure may be performed usingan O2-plasma or solvents. These methods are compatible with many materials which meansthat polymer support allows process steps before release etch such as, e.g., materialdeposition.

The step of forrning the waveguide may be performed after the step of removing the handlingsubstrate. This is the most straight forward method for fabricating the device. If thewaveguide is formed before the step of removing the handling substrate it must be formedalso before attachment of the device layer assembly on the substrate. Thus, care must be takenduring the following process steps in order not to harrn the waveguide to guarantee sufficientalignment of the waveguide to any existing structure or component present on/in the substrateand to guarantee sufficient alignment of the waveguide to following process steps such as,e.g., photolithography.

The step of forrning the support structure may be performed after the step of removing thehandling substrate. This provides the same advantages as Was mentioned for the previous feature.

The thickness of the polymer layer may be formed to be in the interval 5 nm to 100 um,preferably 200 nm - 50 um, most preferably 3-20 um. The loW part of the first intervalrequires the support structure to be constituted by other materials apart from the polymercontact layer(s). In order to provide a reliable polymer contact layer(s) the thickness of the polymer contact layer(s) is preferably 200 nm - 50 um, most preferably 3-20 um.

The method may comprise the steps of forrning, in the device layer, a substructure comprisingat least one subelement arranged at a distance from the Waveguide, and forrning, in the devicelayer, connection means With Which the Waveguide is connected to the substructure. Whereinthe support structure is formed to extend from the substrate to the substructure. By formingsuch substructures, the side of the Waveguide facing the substrate may be completely freefrom material. This minimizes the losses through this side of the Waveguide. HoWever, inorder to provide suspension of the Waveguide, connection means have to be provided in the device layer.

The substructure may comprise a plurality of subelements. By having the substructure dividedin a plurality of subelements the losses of electromagnetic energy from the Waveguide may befurther reduced. Another benefit from having subelements is that the footprint of the substructure is minimized. Thus, area is made free for other components.

The connection means may be formed as a plurality of bridges. By forming the connectionmeans in the form of a plurality of bridges the losses of electromagnetic energy through theconnection means is minimized. The bridges may have a smaller height than the Waveguide tofurther enhance the confinement of the electromagnetic Wave in the Waveguide and to thereby reduce the losses.

The support structure may be formed to extend from the substrate to the Waveguide. This is analtemative to having the Waveguide suspended in substructures. This enables a maximizedarea of the Waveguide on the device. The advantages of having this structure is simplified fabrication and minimized footprint area.

The method may comprise the step of removing material from the substrate beloW theWaveguide. This step increases the maximum distance perpendicular to the substrate plane,consisting of free-space between the Waveguide and any solid material below the Waveguide.

This leads to reduced losses from the Waveguide. With this step a large distance may be ll achieved between the waveguide and the substrate while still using a thin polymer layer. Thismethod step requires the support structure to extend from the substrate to a substructure connected to the waveguide with connection means.

The method may comprise at least one processing step chosen from photolithography and/ormaterial deposition and/or therrnal processing and/or surface functionalization and/or layertransfer processes and/or wet/ dry etching processes. These are standard processing steps inwafer fabrication and are possible to combine with the method according to the second aspect of the invention.

The method may comprise the step of forrning metal lines and/or active devices, such astransistors, light sources and detectors. The metal lines and/or active devices may be arranged,in or in contact with the device layer and/or the substrate and/or between the device layer andthe substrate. This enables integration of suspended waveguides on top of preprocessedwafers with e. g. CMOS circuits for readout/control of source and detectors.

The removal of polymer from the polymer layer may comprise at least one step of anisotropicor isotropic oxygen plasma etching, or combinations thereof Oxygen plasma etching is afavourable method for removal of material from the polymer layer. This is because oxygenplasma etching is compatible with many materials and provides good process control. Also,the problem of stiction does not exist with oxygen plasma etching. By having anisotropic andisotropic etching steps it is possible to obtain various shapes of the support structure enabling,e. g., high aspect ratio pillars.

Short description of the figures Fig. l shows in a top view a device, comprising a waveguide supported on a substrate according to an embodiment of the present invention.

Fig. 2 shows in a perspective sectional view a part of the device in Fig. 2 according to an embodiment.

Fig. 3 shows the cross-section A-A in Fig. 2 according to an embodiment.

Fig. 4 shows the cross-section A-A in Fig. 2 according to another embodiment.

Fig. 5a shows in a top view a part of a device according to an altemative embodiment.

Fig. 5b shows in a top view a part of a device according to an altemative embodiment. 12 Fig. 6 shows the cross-section B-B in Fig. 5a and 5b.Fig. 7 shows the cross-section C-C in Fig. 5a and 5b according to two different embodiments.

Fig. 8 shows a cross-section of a part of a device according to two different embodiments of the invention.Fig. 9a-9f illustrates the method for fabricating a device according to Figs. 1-8.

Description of embodiments In the following description of embodiments of the invention the same reference numerals will be used for equivalent features in the different figures. The figures are not drawn to scale.

Fig. 1 shows in a top view a device 1 according to an embodiment of the present invention.The device 1 comprises a waveguide supported by support elements 8 on a substrate 2. Thewaveguide def1nes a closed circuit along a length direction L. Fig. 2 shows in a perspectivesectional view a part of the device in Fig. 2 according to an embodiment of the invention. Fig.3 shows the cross-section A-A in Fig. 2 according to an embodiment of the invention. Thedevice will initially be described with reference to primarily Figs. 2 and 3. The device 1 (Fig.1) comprises, a device layer 4, a substrate 2 def1ning a substrate plane 3 extending through thepoint of the substrate 2 being closest to the device layer 4, and a waveguide 7 for guiding anelectromagnetic wave. The side of the device layer 4 facing the substrate 2 defines a devicelayer plane 5 (Fig. 3). The waveguide extends in a length direction L (Figs. 1 and 2) in thedevice layer 4. The waveguide 7 has a width w in the device layer plane 5 (Fig. 3) in adirection perpendicular to the length direction L, and a height h out of the device layer plane 5(Fig. 3) in a direction perpendicular to the length direction L. The waveguide 7 is supportedon the substrate 2 via a support structure 6 extending from the substrate 2 to the device layer4. In the embodiment of Figs. 1-3 the side of the waveguide 7 facing the substrate 2 is partlyfree from contact with the support structure, which is clearly visible in Fig. 2 wherein thesupport element 8, which forms part of the support structure 6, only extends along a limitedlength of the waveguide 7. The waveguide is free-hanging on both sides of the supportelement 8 in Fig. 2. The width w and height h of the waveguide deterrnines a maximumwavelength that is suitable to transmit by the waveguide. The distance, perpendicular to thesubstrate plane 3, between the device layer plane 5 and the substrate plane 3, is denoted D2 inFig. 3. The maximum distance, perpendicular to the substrate plane 3, consisting of free-spacebetween the waveguide 7 and any solid material below the waveguide is denoted D1 in Fig. 3.In the embodiment shown in Fig. 3 D2 is equal to Dl. The device layer 7 is of a different material than a polymer, and the support structure 6 comprises a polymer layer 18. In Figs. 2 13 and 3 the polymer layer 18 extends from the substrate 2 to the device layer 4 and is also incontact with the substrate 2 and the device layer 4. Thus, the support element 8 is madeentirely of polymer. The device layer plane 5 is parallel to the substrate plane 3. Shown inFig. 2 is a comparison cross section 25 which is parallel to the substrate plane 3, extendsthrough the polymer layer 18 at a spacing y perpendicularly from the substrate plane 3, andextends perpendicularly to the length direction L to a breadth x, equal to the width W of thewaveguide, from a side s of the support structure 6 being closest to the waveguide. Thespacing y is chosen to maximize a ratio r of the area of the polymer layer within thecomparison cross section 25 to the area of the support structure within the comparison crosssection 25. In this case the support structure is made entirely of a polymer and the ratio is 1irrespective of the spacing y. The comparison cross section 25 extends along the entire length of the waveguide.

The device 1 shown in Figs. 1-3 alleviates the problems with mechanical stresses in devicelayer 4 and the waveguide 7 irrespective of the distance D2 perpendicular to the substrateplane 3, between the device layer plane 5 and the substrate plane 3. The distance D2 can bemade larger than 10 um without introducing mechanical stresses in the device layer.However, in order to alleviate also the problems with losses from the waveguide themaximum distance D1, perpendicular to the substrate plane 3, consisting of free-spacebetween the waveguide 7 and any solid material below the waveguide 7, should be at least 2 um.

Another big advantage with having a polymer layer is that the device layer can be made thin.The ratio between the distance D2, perpendicular to the substrate plane 3, between the device layer plane 5 and the substrate plane 3, and the waveguide height h may be >10.

With a structure according to the embodiments in Fig. 2 and Fig. 3 the distance between thesubstrate 2 and the device layer 4 may be made considerably thicker than has been done in theprior art with almost no mechanical stresses in the device layer. Also, the losses from thewaveguide are alleviated in comparison to the prior art due to the favorable properties ofpolymer with regard to affecting the electromagnetic wave in the adj acent waveguide 7. Also,in absolute quantities the distance D2, perpendicular to the device layer plane 5, between thedevice layer plane 5 and the substrate plane 3 can easily be manufactured to be bigger than 2um, preferably 3 um, more preferably 4 um, more preferably 6 um, and most preferred 10um. Altematively, it is of course possible to make the polymer layer thin. The polymer layer may be as thin as 5 nm. 14 The width ws of the support structure 6 at the point of support of the waveguide 7 is smallerthan the width W of the waveguide 7 as can be seen in Fig. 3. It is possible to have the widthws of the support structure 6 at the point of support of the waveguide 7 larger than the widthw of the waveguide 7.

Fig. 4 shows the cross-section A-A in Fig. 2 according to another embodiment of theinvention. In contrast to the embodiment of Fig. 3 the device shown in Fig. 4 comprises morelayers. More specif1cally 5 layers are shown in Fig. 4. The substrate 2 may be a siliconsubstrate and the device layer 4 and waveguide 7 may be of silicon. The layer 13 in contactwith the substrate 2 may be a thick oxide layer. As is indicated by the parts of the thick oxidelayer 13 on the sides the thick oxide layer may have covered the entire substrate beforecommencing fabrication of the device. The layer in contact with the waveguide 7 may be ametal layer 14. The metal layer 14 may be used during fabrication of the device. Finally, thelayer between the thick oxide layer 13 and the metal layer 14 may be a polymer layer 18,which constitutes the polymer contact layer 22, 23. The polymer layer 18 fi1nctions as amechanical contact layer during fabrication of the device as will be evident from thedescription of the method below. Also, in this case, the ratio r is 1 as the polymer layer 18 extends from side to side of the support element 8.

The materials in the substrate 2, the support structure 6 and the device layer 4/waveguide 7,may be chosen from the materials indicated below. However, as is indicated by the differenthatchings the material of the support structure 6 in contact with the device layer 4 is differentfrom the material in the device layer, and the material of the support structure 6 in contactwith the substrate 2 is different from the material in the substrate. Also, D1 and D2 are equalto each other in Fig. 4.

In the embodiments shown in Figs. 2-4 the device layer 4 is equivalent to the waveguide 7.However, the term device layer more generally refers to the layer from which the waveguideis fabricated. Another common feature is that the device layer plane 5 is essentially parallel tothe substrate plane 3.

Fig. 5a shows in a top view a part of a device according to an altemative embodiment. In Fig.5a the device layer 4 comprises a substructure ll, comprising a plurality of subelements 12,arranged at a distance from the waveguide 7, wherein the waveguide 7 is connected to thesubstructure 11 with connection means 15 in the device layer 4 in the form of a plurality ofbridges 16. The support structure 6 is in the form of a plurality of support elements 8 whicheach extend from the substrate 2 to a respective subelement 12. The substructure ll is connected to the waveguide 7 with a plurality of bridges 16, which each extend from the waveguide to a respective subelement 12. The support elements 8 comprise a polymer. Thedistance between the support structure 6 and the waveguide 7 is denoted D3 in Fig. 5a and 5b.The ratio of said distance D3 to the width W of the waveguide 7 is about 2-3 in Fig. 5 but maybe as big as 100 and as small as l. Fig 5b shows in a top view a part of a device according toan alternative embodiment. In Fig. 5b the connection means 15 are in the forrn of acontinuous membrane 24. Due to the fabrication process of a membrane, the membrane 24might contain ho les (not shown) which are necessary if material needs to be removedundemeath by under etching. The membrane 24 extends along each side of the waveguide 7as is shown in Fig. 5b. The comparison cross section 25 extends between the two parallellines 30, 30' in Figs. 5a. The distance between the two lines 30, 30', corresponds to theextension x of the comparison cross section 25. The extension x is equal to the width w of thewaveguide. In Fig. 5a and 5b two of the support elements comprises core elements 33 madeof a conductive material. This will lead to a ratio r being less than l. As the comparison crosssection extends along the entire length of the waveguide it is not possible to determine theratio r from Figs. 5a and 5b. However, assuming that the pattem shown in Figs. 5a and 5brepeats itself along the entire length of the waveguide, i.e., that every second pair of supportelements comprise a core element 33 made of a conductive material, the ratio r is more than 0.95 in the embodiment shown in Figs. 5a and 5b.

Fig. 6 shows the cross-section B-B in Fig. 5a and 5b which both have the same cross sections.From Fig. 6 it is evident that the height hb, hm, of the bridges 16 and the membrane 24,respectively, is a smaller than the height h of the waveguide 7. This difference in heightbetween the waveguide 7 and the connection means l5 will ensure proper confinement of theelectromagnetic wave within the waveguide 7. It is also shown in Fig. 6 that material has beenremoved from the substrate 2 below the waveguide 7 resulting in that the maximum distanceDl, perpendicular to the substrate plane 3, consisting of free-space between the waveguide 7and any solid material below the waveguide is larger than the distance D2, perpendicular tothe substrate plane 3, between the device layer plane 5 and the substrate plane 3. Thus, Dl >D2 in the embodiment shown in Fig. 6. The materials of the different layer can be chosen asdescribed below. The height of the connection means in Fig. 6 is less than 50% of the height hof the device layer.

Fig 7 shows the cross-section C - C of Fig. 5 according to two different embodiments. In theembodiment to the left in Fig. 7 the support element 8 is made of metal and extends from thesubstrate through the device layer. In the embodiment to the right in Fig. 7 the supportelement 8 comprises a core element 33 made of a conductive material and extends from the substrate 2 through the device layer 4. The support element is also surrounded by a different 16 material. When fabricating a support element as shown to the right the structure shown in Fig.6 is first fabricated. A hole is then forrned through the device layer and the support element 8.Finally, the hole is filled with metal to arrive at the structure shown to the right in Fig. 7. Inorder to arrive at the support element shown to the left in Fig. 7 the material surrounding thecore element 33 is removed. A metal connection between the substrate 2 and the device layeris useful to provide an electrical connection between a device in the substrate 2 and a device in the device in the device layer 4.

Fig. 8 shows a cross-section of a part of a device according to two different embodiments ofthe invention. The embodiments shown in Fig. 8 both comprise a substrate 2 on/in whichmetal lines 19 and different active devices 20 have been formed such as FETs (Field EffectTransistors). The metal lines 19 and the active devices 20 are embedded into an oxide layer21. The support elements 8 on top of the oxide layer 21 forms part of the support structure 6.The oxide layer 21 also forms part of the support structure 6. The oxide layer 21 and the support elements 8 together forms the support structure 6.

The comparison cross section 25 is indicated in Figs. 2, 4, 6, 7, and 8, by its extension xperpendicularly to the length direction from a side of the support structure 6. The extension xis equal to the width w of the waveguide 7. The distance D3 between the waveguide 7 and thesupport elements 8 is slightly larger than the width w of the waveguide 7 in the embodimentsshown in Figs. 6-8.

In all embodiments described above it is advantageous to have the width w of the waveguide7 at least 5 times the height h of the waveguide 7. By designing the waveguide in this way,the electromagnetic wave in the waveguide will be affected primarily by the top and bottomsides of the waveguide and to a smaller extent by the sides between the top and bottom sides.As it is easier to control the quality of the top and bottom sides said ratio will ensure a good quality of the waveguide.

In all embodiments described above the height h of the waveguide 7 is preferably smaller thanthe wavelength of the electromagnetic wave to be guided in order to better control the mode of the electromagnetic wave through the waveguide 7.

The invention is aimed at providing a device as defined in the claims, wherein the waveguide7 is optimized for guiding an electromagnetic wave with a wavelength within the range of 0.4-100 um, preferably 1.2-20 um, and most preferred within 3-12 um. 17 The devices described above may comprise metal lines 19 (Fig. l) and/or active devices 20(Fig. 1), such as transistors, light sources and detectors, in or in contact with the device layer4 and/or the substrate 2.

Fig. 9a-9f illustrates a method for fabricating a device according to Fig. 3 according to anembodiment of the invention. The method starts with the provision of a handling substrate 26on which a device layer 4 is arranged. In the example shown in Fig. 9a the handling substrate26 is a silicon wafer which has been oxidized to produce an optional interrnediate layer 28 inthe form of a SiO2-layer 28. A device layer 4 has then been fabricated on the interrnediatelayer 28. The handling substrate 26, the interrnediate layer and the device layer form a devicelayer assembly 27. Also, a substrate 2 is provided on which a polymer contact layer 22 isprovided. As an altemative to the embodiment shown in Fig. 9 it is possible to provide apolymer contact layer 23 on the handling substrate 26, in addition to or instead of the polymercontact layer 22 on the substrate 2. This optional polymer contact layer 23 is shown withdashed lines in Fig. 9a. Below is a list of possible polymers that may be chosen for the contact layer.

In a second step illustrated in Fig. 9b the device layer assembly 27 is attached on the substrate2 with the device layer 4 arranged between the handling substrate 26 and the substrate 2,using the polymer contact layer(s) as a connecting layer. The attachment of the device layerassembly 27 to the substrate 2 is performed by applying a pressure and heat to the handlingsubstrate 26 and the substrate 2. Depending on the polymer used in the polymer contactlayer(s) 22, 23, the temperature and pressure applied may vary. When using polymer ascontact layer(s) 22, 23, a suitable temperature interval is 20-500°C. Preferably, a temperaturebetween 20-250°C is used. A suitable pressure at the bond interface applied between 0.1-200bar. When polymer is used as contact layer(s) 22, 23, the bonding can be performed in vacuum or atmospheric pressure.

In a third step illustrated in Fig. 9c the handling substrate 26 and the optional interrnediatelayer are removed after attachment of the device layer assembly 27 to the substrate 2.Preferably, a suitable etching technique is used to remove the handling. The etching technique is chosen according to the material in the handling substrate 26.

In a fourth step illustrated by Fig. 9d material is removed from the device layer 4 to form thewaveguide 7. The material in the device layer 4 is preferably removed using an etchingtechnique adapted to the material in the device layer 4. As an altemative it is possible to form the waveguide 7 before the step of attaching the device layer assembly on the substrate 2. 18 In a fifth step illustrated by Fig. 9e and a Sixth step illustrated by Fig. 9f material is removedbetween the device layer and the substrate to form the support structure 6 as has beendescribed above. The material between the device layer 4 and the substrate 2 is preferablyremoved in a two-step process. In a first removal step illustrated by Fig. 9e the material in thepolymer contact layer(s) 22, 23, is removed on the sides of the waveguide by a verticaletching method. In a second removal step illustrated by Fig. 9f material is removed below thewaveguide 7 using under-etching in order to form the support structure 6. The support structure 6 is formed to extend from the substrate 2 to the waveguide 7.

As an altemative the forrning of the support structure may be performed before the step ofremoving the handling substrate. According to this altemative the support structure is preferably formed before attachment of the device layer assembly 27 on the substrate 2.

The method may also comprise the steps of forrning, in the device layer 4, a substructure 11arranged at a distance from the waveguide 7, and forrning, in the device layer 4, connectionmeans 15 with which the waveguide 7 is connected to the substructure 11. The supportstructure 6 is formed to extend from the substrate 2 to the substructure 11. In order to arrive atthe device according to Figs. 5a and 6 the substructure 11 is formed as a plurality of subelements 12, and the connection means 15 is formed as a plurality of bridges 16.

In order to arrive at the device according shown to the right in Fig. 7 the method comprisesthe steps of removing material in regions between the substructure 4 and the substrate 2 andforming a core element 33 in each one of said regions. The core elements 33 may comprise aconductive material. In order to arrive at the device shown to the left in Fig. 7 the materialsurrounding the core element 33 is removed to arrive at a support element 8 being constitutedby the core element 33.

The thickness chosen for the polymer contact layer(s) 22, 23, depends on many differentparameters. Preferably, the thickness of the polymer contact layer is in the interval 5 nm to100 um. The low part of the interval requires the support structure 6 to be constituted by othermaterials apart from the polymer contact layer(s) 22, 23, as is shown in Fig. 4. However, inorder to provide a reliable polymer contact layer(s) 22, 23, the thickness of the polymercontact layer(s) is preferably 200 nm - 50 um, most preferably 3-20 um.

As is shown in Fig. 8 the method may comprise the step of forrning metal lines 19 and/oractive devices 20, such as transistors, light sources and detectors, in or in contact with the substrate 2 and/or the device layer 4. 19 Lists of materials for the different layers In the following lists of suitable materials for the different layers will displayed.

The material in the waveguide 7, i.e., device layer 4, may be chosen from the followingmaterials: Silicon Silicon gerrnanium Gerrnanium Silicon nitride III-V materials, such as GaAs, InP, InGaAs, and InGaP Chalcogenide glass Indium(III)-fluorid Diamond Sapphire Lithium niobate and other nonlinear materials Piezoelectric materials The material in the substrate 2 may be chosen from the following materials:Silicon CMOS Glass (SiO2-based glasses) Gerrnanium Polymer Sapphire III-V materials, such as GaAs, InP, InGaAs, InGaP, etc.

Diamond Metals Silicon carbide The material between the substrate and the device layer might be a combination of differentmaterials stacked horizontally or Vertically. These different materials may be chosen from thefollowing materials: Polymer Metals (TiW, Ni, Au, W, Al, Cr, Ti, Cu, Ag) Dielectrics (SiO2, SiN, Al203) Semiconductors such as, e.g., Si, SiGe.

The polymer may be chosen from the following materials: polymer adhesives, therrnoplastic polymers, therrnoset polymers, elastomers, hybridpolymers, specific polymer adhesives such as, eg., BCB, nanoimprint resist, epoxy, SUS,PDMS, and PMMA.

The inVention is not limited to the described embo diments but may amended in many WaysWithout departing from the scope of the inVention Which is limited only by the appended claims.

Claims (36)

1. l. Anordning (l) innefattande; ett anordningsskikt (4); ett substrat (2) som definierar ett substratplan (3) som sträcker sig genom punkten försubstratet som är närmast anordningsskiktet; en vågledare (7) för ledning av en elektromagnetisk våg, varvid vågledaren sträcker sig i enlängdriktning (L) i anordningsskiktet (4), varvid vågledaren (7) har en bredd (W) ianordningsskiktplanet (5) i en riktning vinkelrät mot längdriktningen (L), och en höjd (h) utur anordningsskiktplanet (5) i en riktning vinkelrät mot längdriktningen; och en stödstruktur (6), varvid stödstrukturen (6) sträcker sig från substratet (2) till anordningsskiktet (4) för attunderstödja vågledaren (7) på substratet (2), och varvid ett anordningsskiktplan (5) sträcker sig parallellt med substratplanet (3) genompunkten hos anordningsskiktet (4) som understöds via stödstrukturen som är närmastsubstratplanet (3), kännetecknad av att anordningsskiktet (7) är av ett material valt från: kisel, kiselgerrnanium, gerrnanium,kiselnitrid, III-V-material, så som GaAs, InP, InGaAs och InGaP, kalkogenidglas,indium(III)-fluorid, diamant, safir, litiumniobat och andra ickelinj ära material, piezoelektriskamaterial, och att stödstrukturen (6) innefattar ett polymerskikt (l 8), varvid ett jämförelsetvärsnitt (25) sträcker sig, parallellt med substratplanet (3) genompolymerskiktet (l 8) pä ett avstånd (y) vinkelrät mot substratplanet (3), och sträcker sigvinkelrät mot längdriktningen (L) till en bredd (x), lika med vågledarens bredd (W), från ensida av stödstrukturen (6) som är närmast vågledaren, varvid avståndet (y) är valt för att maximera ett förhållande (r) på ytan av polymerskiktetinom jämförelsetvärsnittet (25) i förhållande till ytan på stödstrukturen inomjämförelsetvärsnittet (25), och varvid förhållandet (r) är åtminstone 0.5.

2. Anordning (l) enligt patentkrav l, varvid anordningsskiktet är väsentligen parallellt med substratplanet (3).

3. Anordning (l) enligt patentkrav l eller 2, varvid polymerskiktet (l 8) är i kontakt medanordningsskiktet (4).

4. Anordning enligt patentkrav 1, 2 eller 3, varvid förhållandet (r) är åtrninstone 0.80, företrädesvis åtminstone 0.90 och mest föredraget 0.95.

5. Anordning (1) enligt något av föregående patentkrav, varvid avståndet (D2) vinkelrät motsubstratplanet (3), mellan anordningsskiktplanet (5) och substratplanet (3) är åtminstone 2tim, företrädesvis åtminstone 3 tim, mera föredraget åtminstone 4 tim, mera föredraget åtminstone 6 tim, och mest föredraget 10 tim.

6. Anordning (1) enligt något av föregående patentkrav, varvid förhållandet mellan detmaximala avståndet (Dl), vinkelrät mot substratplanet (5), bestående av fritt utrymme mellanvågledaren (7) och något fast material under vågledaren (7), och vågledarhöj den (h) är >6, företrädesvis >8, mest föredraget >10.

7. Anordning (1) enligt något av föregående patentkrav, varvid anordningsskiktet (4)innefattar en understruktur (11), innefattande åtminstone ett underelement (12), anordnat påett avstånd från vågledaren (7), varvid vågledaren (7) är förbundet med understrukturen (11)med förbindelsemedel (15) i anordningsskiktet (4), och varvid stödstrukturen (6) sträcker sigfrån substratet (2) till understrukturen (11).

8. Anordning (1) enligt patentkrav 7, varvid förbindelsemedlet (15) är i formen av ettmembran (24) som sträcker sig längs var sida av vågledare (7), varvid membranet (24) har enhöjd (hm) som inte är större än 98 % av vågledarens (7) höjd (h), företrädesvis inte mer än 95 % av vågledarens (7) höjd (h), och mest föredraget inte mer är 80 % av vågledarens (7) höjd (h).

9. Anordning (1) enligt patentkrav 7, varvid understrukturen (11) innefattar en pluralitet underelement (12).

10. Anordning (1) enligt patentkrav 7 eller 9, varvid stödstrukturen (6) innefattar en pluralitet av stödelement (8) som sträcker sig från substratet (2) till understrukturen (11).

11. Anordning (1) enligt patentkrav 7, 9 eller 10, varvid förbindelsemedlet (15) innefattar en pluralitet av broar (16) som förbinder vågledaren (7) med understrukturen (11).

12. Anordning (1) enligt något av patentkraven 7-11, varvid förhållandet mellan avståndet(D3) mellan stödstrukturen (6) och vågledaren (7) och vågledarens (7) bredd (W) är 0.5-100,företrädesvis 1-10, och mest föredraget 2-5.

13. Anordning (1) enligt något av patentkraven 1-6, varvid stödstrukturen (6) sträcker sig frånsubstratet (2) till vågledaren (7).

14. Anordning enligt patentkrav 13, varvid förhållandet (r) mellan ytan på polymerskiktetinom jämförelsetvärsnittet och ytan på stödstrukturen inom jämförelsetvärsnittet är åtminstone 0.98, företrädesvis åtminstone 0.99.

15. Anordning enligt patentkrav 13, varvid polymerskiktet (18) sträcker sig över hela stödstrukturens (6) tvärsnittsyta i jämförelsetvärsnittet (25).

16. Anordning (1) enligt något av patentkraven 13-15, varvid bredden på stödstrukturen (6)vid stödpunkten för vågledaren (7) är mindre än bredden (W) på vågledaren (7).

17. Anordning (1) enligt något av patentkraven 13-16, varvid stödstrukturen (6) innefattar enpluralitet stödelement (8) så att vågledaren (7) är frihängande mellan två närliggandestödelement (8).

18. Anordning (1) enligt patentkrav 17, varvid åtminstone ett av stödelementen (8) är gjort uteslutande av en polymer.

19. Anordning (1) enligt något av föregående patentkrav, varvid bredden (W) på vågledaren (7) är åtminstone 5 gånger vågledarens (7) höjd (h).

20. Anordning (1) enligt något av föregående patentkrav, varvid vågledarens (7) höjd (h) är mindre än våglängden på den elektromagnetiska vågen som skall ledas.

21. Anordning (1) enligt patentkrav 20, varvid vågledaren (7) är anordnad för ledning av enelektromagnetisk våg med en våglängd inom området 0.4-100 pm, företrädesvis 1.2-20 pm, och mest föredraget inom 3-12 pm.

22. Anordning (1) enligt något av föregående patentkrav, varvid polymerskiktets (18) tjocklekär 5 nm till 100 pm, företrädesvis 200 nm till 50 pm, och mest föredraget 3-20 pm.

23. Anordning (1) enligt något av föregående patentkrav, varvid stödstrukturen (6) innefattar ledande material som sträcker sig från anordningsskiktet (4) till substratet (2).

24. Anordning enligt något av föregående patentkrav, innefattande metallinj er (19) och/eller aktiva anordningar (20), så som transistorer, ljuskällor och detektorer.

25. Förfarande för tillverkning av en anordning (l) innefattande ett anordningsskikt (4); ett substrat (2) som definierar ett substratplan (3) som sträcker sig genom punkten hossubstratet som är närmast anordningsskiktet; en vågledare (7) för ledning av en elektromagnetisk våg, varvid vågledaren sträcker sig i enlängdriktning (L) i anordningsskiktet (4), varvid vågledaren (7) har en bredd (W) ianordningsskiktplanet (5) i en riktning vinkelrät mot längdriktningen (L), och en höjd (h) utur anordningsskiktplanet (5) i en riktning vinkelrät mot längdriktningen; och en stödstruktur (6), varvid stödstrukturen (6) sträcker sig från substratet (2) till anordningsskiktet (4) för attunderstödja vågledaren (7) på substratet (2), och varvid ett anordningsskiktplan (5) sträcker sig parallellt med substratplanet (3) genompunkten hos anordningsskiktet (4) som understöds via stödstrukturen som är närmastsubstratplanet (3), varvid förfarandet innefattar stegen: att tillhandahålla ett hanteringssubstrat (26) på vilket ett anordningsskikt (4) är anordnat,varvid hanteringssubstratet (26) och anordningsskiktet (4) bildar enanordningsskikthopsättning (27), att tillhandahålla ett substrat (2), att tillhandahålla ett polymerkontaktskikt (22, 23) på substratet (2) och/eller påanordningsskikthopsättningen (27), på samma sida som anordningsskiktet (4), att fästa anordningsskikthopsättningen (27) på substratet (2) med anordningsskiktet anordnatmellan hanteringssubstratet (26) och substratet (2), så att polymerkontaktskiktet(en) (22, 23)bildar polymerskiktet (l 8), att avlägsna hanteringssubstratet (26) efter fästande av anordningsskikthopsättningen (27) påsubstratet (2), att avlägsna material från anordningsskiktet (4) för att bilda vågledaren (7), att avlägsna material från polymerkontaktskiktet(en) (22, 23) för att bilda stödstrukturen (6),varvid anordningsskiktet (4) är av ett annat material än en polymer, varvid stödstrukturen (6) innefattar ett polymerskikt (l 8), varvid ett jämförelsetvärsnitt (25) sträcker sig, parallellt med substratplanet (3) genompolymerskiktet (l 8) på ett avstånd (y) vinkelrät mot substratplanet (3), och sträcker sigvinkelrät mot längdriktningen (L) till en bredd (x), lika med vågledarens bredd (W), från ensida av stödstrukturen (6) som är närmast vågledaren, varvid avståndet (y) är valt för att maximera ett förhållande (r) på ytan av polymerskiktet inom jämförelsetvärsnittet (25) i förhållande till ytan på stödstrukturen inom jämförelsetvärsnittet (25), och varvid förhållandet (r) är åtrninstone 0.5.

26. Förfarandet enligt patentkrav 25, varvid steget att bilda vågledaren (7) utförs efter steget att avlägsna hanteringssubstratet (26).

27. Förfarande enligt patentkrav 25 eller 26, varvid steget att bilda stödstrukturen (6) utförs efter steget att avlägsna hanteringssubstratet (26).

28. Förfarande enligt något av patentkraven 25-27, varvid polymerskiktets (18) tjocklek ärbildat att vara i intervallet 5nm till 100 um, företrädesvis 200 nm - 50 um, mest föredraget 3-20 um.

29. Förfarande enligt något av patentkraven 25-28, innefattande stegen att bilda, i anordningsskiktet (4), en understruktur (ll) innefattande åtminstone ettunderelement (l2) anordnat på ett avstånd från vågledaren (7), att bilda, in anordningsskiktet (4), förbindelsemedel (l5) med vilket vågledaren är förbundenmed understrukturen (1 1), och varvid stödstrukturen (6) är bildad för att sträcka sig från substratet till understrukturen.

30. Förfarande enligt patentkrav 29, varvid understrukturen (ll) är bildad som en pluralitet underelement (12).

31. 3 l. Förfarande enligt patentkrav 29 eller 30, varvid förbindelsemedlet (l5) är bildat som enpluralitet broar (l6).

32. Förfarande enligt något av patentkraven 25-28, varvid stödstrukturen (6) är bildad attsträcka sig från substratet (2) till vågledaren (7).

33. Förfarande enligt något av patentkraven 25-3 l , innefattande steget att avlägsna material från substraten (2) under vågledaren (7).

34. Förfarande enligt något av patentkraven 25-33, innefattande åtminstone ettbehandlingssteg valt från fotolitograf1 och/eller materialdeponering och/eller termiskbehandling och/eller ytfianktionalisering och/eller skiktöverföringsprocesser och/eller våta/torra etsningsprocesser.

35. Förfarande enligt något av patentkraven 25-34, innefattande steget att bilda metallinj er(l9) och/eller aktiva anordningar (20), så som transistorer, ljuskällor och detektorer, i eller på anordningen (l).

36. Förfarande enligt något av patentkraven 25-35, innefattande steget att avlägsna material från substratet under Vågledaren.