A method for manufacturing parts using atomic diffusion bonding.

Abstract

To provide a method for manufacturing a component by joining two plates and constructing a metal layer embedded between the plates.SOLUTION: Two plates are electrically insulated. At least one of the plates is optically transparent and forms at least one flat conductor unit and at least one isolator unit between the plates. With a method, a metal layer is disposed between the plates. The metal layer is locally heated using laser irradiation to process the metal layer so that the metal layer is converted into at least one isolator unit in part of a region. A least one conductor unit is formed adjacent to at least one isolator unit to convert the metal layer into the isolator unit beyond a line or an area. The plate is ground on a bonding surface side. A bonding surface is formed by a metal bonding layer. Bonding of the plate includes an atomic diffusion bonding. The metal bonding layer forms the metal layer between the bonded plates.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing components from two plates, both plates being electrically insulated, at least one of the plates being optically transparent, with at least one flat conductor part and at least one isolator part formed between the plates. Specifically, it relates to a method for processing components having a sandwich structure in which a metal layer is embedded, for example, a method for processing components formed by bonding, the components having a metal intermediate layer. The use of the present invention is to manufacture tools for holding or moving workpieces such as semiconductor wafers or glass wafers under the influence of an electric field, or to manufacture conductor components, particularly resistive heating elements.

Background Art

[0002] In this specification, the following prior arts that constitute the technical background for the present invention are referred to. [1] U.S. Patent No. 7,092,231 [2] U.S. Patent No. 6,864,957 [3] U.S. Patent Application Publication No. 2012 / 0236458 [4] European Patent No. 1,637,271 [5] U.S. Patent Application Publication No. 2011 / 0288648 [6] "J. of Material Science" 27(1992), 569 - 579 by O.M. Akselsen [7] "Material Science and Engineering" B176, 60 - 64(2011) by Thomas J. Moore [8] "Diffusion Bonding of Silicon Carbide Ceramics Using Titanium Interlayer" by Michael C. Halbig et al., NASA, 22.01.2006 http: / / ntrs.nasa.gov / archive / nasa / casi.ntrs.nasa.gov / 20060051742.pdf [9] European Patent Application Publication No. 0093199

[10] European Patent No. 0076467

[11] German Patent No. 3003186 Specification

[12] German unpublished patent application No. 102019101657.6 (unpublished as of the priority date of the present invention)

[13] European Patent Application Publication No. 3196926

[14] "IEICE TRANS. ELECTRON." by E. Higurashi et al., Bd.E100-C, No. 2, February 2017, "Room-Temperature Bonding of Wafers with Smooth Au Thin Films in Ambient Air Using a Surface-Activated Bonding Method"

[15] T. Suga et al., "MRS Advanced Materials, Materials Research Society" 8, 257 (1989)

[16] T. Suga et al., "Acta Metall.Mater.", 40, 133 (1992)

[0003] Tools that process workpieces using the effect of an electric field, specifically electrostatic holding devices (so-called electrostatic clamps, electrostatic chucks) that hold wafers, are commonly known (see, for example, [1], [2]). An electrostatic holding device comprises a planar component having, for example, two electrodes formed of thin metal layers. When a high voltage is applied to the electrodes, an electric field is generated in the environment, and this effect attracts the wafer to the holding device. The wafer can be moved using the holding device, for example, between different work stations in a coating plant, as long as a high voltage is applied.

[0004] In conventional electrostatic holding devices, electrodes are formed by depositing a metal layer on the surface of a carrier, then constructing another metal layer, and finally covering the constructed metal layer with an insulating coating layer. The coating layer functions as both a dielectric and a protector for the electrodes. This method is disadvantageous due to its complexity, especially when carriers made of electrochemically bonded glass plates are used.

[0005] Furthermore, thin metal layers have numerous other applications, such as electrodes, conductors, or resistive elements. In other applications, a coating layer may be applied to the metal layer to protect it from environmental influences. However, coating layers have disadvantages in component manufacturing because they require additional processing costs and can only be applied after the metal layer has been treated, for example, by ablation or etching to suit each application. Moreover, the metal layer may unintentionally change during the deposition of the coating layer.

[0006] Therefore, there is interest in an improved method in which, in the initial stage, the metal layer is embedded between the substrate and the coating layer, or usually between two plates, before the metal layer is processed. For example, [3] describes the manufacture of an electrostatic holding device in such a manner. Glass plates are joined by an anodic junction using a metal junction layer. The metal junction layer is then constructed by locally restricted laser treatment to form at least two electrodes. The laser treatment locally converts the metal junction layer into an insulating layer that separates the electrodes from each other.

[0007] However, the technique described in [3] has disadvantages because it uses anode bonding, which limits the number of suitable plate materials that can be used. Only glass that significantly reduces electrical resistance during the high-temperature phase of the anode bonding and has a coefficient of thermal expansion (around 250°C) suitable for the bonding area may be used. Furthermore, such glass must contain specific ions (e.g., earth alkali ions) so that applying a voltage during anode bonding creates a volume charge region or depletion region at the bonding interface. However, glass is relatively softer than other materials, such as sapphire, diamond, or ceramics. Electrostatic holders manufactured according to [3] are therefore limited in their resistance to abrasion by the held wafer and may have limited wafer holding accuracy. Furthermore, the dielectric properties of glass suitable for anode bonding that are suitable for use in electrostatic holders are quite limited.

[0008] Unlike anodic bonding, diffusion bonding avoids limitations on specific glasses because flat plates are joined together in a uniaxial hot press under the influence of pressure and heat. For example, ceramic plates may be bonded (see [4] to

[11] ). Diffusion bonding is performed, for example, in a hot press at temperatures above 1600°C and pressures above 100 bar (see [4]). In diffusion bonding, a metal layer may be used as the bonding layer.

[0009] The use of diffusion bonding to bond plates in an electrostatic holding device is described in

[12] . In this method, a metal bonding layer can be used as the electrode. However, in contrast to the method in [3], the electrode construction must be carried out before bonding. Furthermore, there are disadvantages due to the limited precision in setting the electrode shape and the high processing temperature. Since diffusion bonding is performed at a much higher temperature than when using an electrostatic holding device, only identical materials, or materials with the same or similar thermal expansion coefficients, can be bonded.

[0010]

[13] describes the manufacture of an electrostatic holding device in which platform-like components are bonded at room temperature by atomic diffusion bonding (ADB). Atomic diffusion bonding does not require an increase in temperature or pressure, in contrast to diffusion bonding. However, the use of atomic diffusion bonding in the plate configuration of the holding device in

[13] is limited to the interface where cooling channels are formed, and is therefore divided into several junctions, each relatively narrow in scope. In this method, electrodes are formed by adding a metal layer to the plate configuration. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] U.S. Patent No. 7092231 [Patent Document 2] U.S. Patent No. 6864957 [Patent Document 3] U.S. Patent Application Publication No. 2012 / 0236458 [Patent Document 4] European Patent No. 1637271 [Patent Document 5] U.S. Patent Application Publication No. 2011 / 0288648 [Patent Document 6] European Patent Application Publication No. 0093199 [Patent Document 7] European Patent No. 0076467 [Patent Document 8] German Patent No. 3003186 [Patent Document 9] German Patent Application Publication No. 102019101657 [Patent Document 10] European Patent Application Publication No. 3196926 [Non-patent literature]

[0012] [Non-Patent Document 1] O.M. Akselsen, Journal of Material Science, 27(1992), 569 - 579 [Non - Patent Document 2] Thomas J. Moore, Material Science and Engineering: B, 176, 60 - 64(2011) [Non - Patent Document 3] Michael C. Halbig, et al., “Diffusion Bonding of Silicon Carbide Ceramics Using Titanium Interlayer”, NASA, 22.01.2006 http: / / ntrs.nasa.gov / archive / nasa / casi.ntrs.nasa.gov / 20060051742.pdf [Non - Patent Document 4] E. Higurashi, et al., “Room - Temperature Bonding of Wafers with Smooth Au Thin Films in Ambient Air Using a Surface - Activated Bonding Method”, IEICE TRANS. ELECTRON., VOL.E100 - C, No.2, February 2017 [Non - Patent Document 5] T. Suga, et al., MRS Advanced Materials, Materials Research Society, 8, 257(1989) [Non - Patent Document 6] T. Suga, et al., Acta Metall. Mater., 40, 133(1992) [Summary of the Invention] [Problems to be Solved by the Invention]

[0013] The object of the present invention is to provide an improved method for manufacturing a part by joining two plates and constructing a metal layer embedded between the plates, thereby avoiding the drawbacks of the prior art. In particular, the present invention is intended to facilitate the manufacture of parts, enable the construction of a metal layer embedded between plates, overcome limitations on plate materials, especially enabling the use of materials with different thermal and / or electrical properties, and / or enabling bonding over a larger bonding surface. [Means for solving the problem]

[0014] This objective is achieved by a method using the features of claim 1. Preferred embodiments and applications of the present invention arise from the dependent claims.

[0015] According to a general embodiment of the present invention, the aforementioned objective is achieved by a method for manufacturing a component from two plates, both of which are electrically insulated and at least one of the plates is optically transparent. The following steps form at least one flat conductive portion (also called an electrode portion or resistive portion) and at least one isolator portion between the plates.

[0016] Each plate is provided with at least one plane on which a bonding layer is supported. The plate surface having the bonding layer is called the bonding surface. The plates are joined along the bonding surface by bonding. Bonding creates a continuous and uninterrupted joint between the two plates, which preferably extends across the entire surface of the plates and is called the joint. As a result of bonding, a metal layer is positioned between the plates. The metal layer is embedded between the plates.

[0017] The term "metal layer" refers to a layer of at least one conductive material made of or containing a metal. The metal layer is preferably 1 μm or less in thickness, 0.1 μm or less, and particularly preferably 50 nm or less, for example 30 nm or less. For example, to ensure the function of the metal layer in the carrier as an electrode or heat resistor, the metal layer is preferably at least 20 nm, preferably at least 50 nm, and particularly preferably at least 0.1 μm, for example 1 μm in thickness, but may be thicker. The metal layer is embedded in the component, i.e., it is positioned in the component such that the metal layer is separated along its surface range on both sides of the plate.

[0018] The bonded plates extend in a plane referred to herein as the principal plane. The direction parallel to the principal plane is also called the transverse direction, and the direction perpendicular to it is the thickness direction. The plates may be called wafers, layers, foils, or flaks. They may each be formed integrally from a single material or from several materials. It is preferable that the plates have the same shape and size in the transverse direction. On faces facing opposite each other, the plates also have flat surfaces or constructed surfaces. Constructed surfaces have, for example, burrs projecting in the thickness direction, with end faces extending transversely across flat burr contact surfaces, or recesses for forming tempering lines, such as cooling channels.

[0019] After bonding, the metal layer is treated by heating it locally and selectively using laser irradiation. Laser irradiation converts the metal layer into at least one isolator region in some areas, and at least one conductive region is formed adjacent to the at least one isolator region. The at least one isolator region is an area where the plate material and the bonding area are electrically insulated. The at least one conductive region is an area where the metal layer is held. Preferably, the at least one conductive region is not irradiated during the processing of the metal layer. In the at least one conductive region, the bonding material is conductive. The plate consists of at least one material that is not sensitive to the localized temperature rise required to convert the metal layer into at least one isolator region.

[0020] The conversion of the metal layer into an isolator is limited to each irradiated area, and as a result, the material of the surrounding plate and adjacent metal layers are unaffected. Undesirable changes to the support, such as deformation caused by heat, can be avoided. Furthermore, the localized action of the laser irradiation makes it possible to process the metal layer with high spatial resolution. This is particularly advantageous when constructing electrodes. Finally, the laser irradiation provides the possibility of easily setting or changing at least one irradiated area of ​​the metal layer. Thus, to form a wide isolator, the optical path of the laser irradiation and the support having the metal layer are moved (scanned) relative to each other to convert the metal layer into at least one isolator over a line or area. Preferably, in this method, the shape and / or size of the metal layer inside the support can be changed to adapt the metal layer to a target form, for example, to have a predetermined function of an electrode or resistive element. The optical path of the laser irradiation may be moved relative to the bonded plate using a movable deflection optical component, or the bonded plate may be moved relative to the deflection optical component of the laser irradiation by mechanical drive.

[0021] For example, one conductor portion and one isolator portion adjacent to the conductor portion, for example, at the edge of a plate, may be formed. Alternatively, two or more conductor portions may be held as untreated portions of the metal layer at the joint, with each isolator portion provided between the untreated portions. For example, at least one isolator portion may divide the metal layer into at least two separate metal layer portions. This variation of the present invention is particularly advantageous for manufacturing electrostatic holding devices having two large-area electrodes configured to be loaded with a high voltage. Furthermore, at least one isolator portion can form a predetermined arrangement of electrodes, allowing for free selection of the geometric shape within the carrier. The electrode arrangement may include, for example, electrode regions and / or electrode strips, particularly linear or curved electrode strips. For example, the electrode arrangement may include two electrodes having comb-like interlocking electrode strips. Such an electrode arrangement is suitable as a non-contact electric drive (linear drive) when an alternating electric field is loaded.

[0022] According to the present invention, before joining the plates, a polished surface is provided on the joining surface side. Polishing involves smoothing the plates with known abrasives and methods (e.g., chemical mechanical polishing, CMP), thereby preparing them for the subsequent joining. Furthermore, the joining surfaces of both plates are each formed by a metallic bonding layer. Preferably, the plates, particularly the plate body or an intermediate layer provided therein, are polished during the preparation step, and each is provided with a metallic bonding layer, for example, by depositing a thin layer. The metallic bonding layer preferably extends across the entire joining surface of the plates.

[0023] Furthermore, the bonding according to the present invention includes atomic diffusion bonding. Atomic diffusion bonding involves bonding plates, each supporting a metallic bonding layer, by forming an intermetallic bond between the bonding layers. The intermetallic bond is formed along a bondfront, which propagates automatically along the principal plane across its entire surface across the opposing bonding surfaces. The intermetallic bond is assisted by the interdiffusion of atoms in the bonding layer to each other's bonding layers. Preferably, one bondfront is formed that propagates along the bonding surface. The bondfront is preferably formed spontaneously or initiated by a temporally and locally limited starting pressure. During the bonding of the plates, an atomic diffusion bond (a bond generated by atomic diffusion bonding) is formed, and the metallic bonding layers form a metallic layer between the bonded plates. The atomic diffusion bond preferably extends across the opposing surfaces of the plates as a seamless seam between the two bonded plates. Atomic diffusion bonding is performed, for example, in a reduced-pressure environment or at atmospheric pressure. Atomic diffusion bonding is performed at a temperature below the softening temperature of the plate material, preferably 300°C or lower, and particularly preferably 200°C or lower.

[0024] The use of atomic diffusion bonding offers a particular advantage over anodic bonding by [3] or diffusion bonding by

[12] , which is that the bonding of plates is significantly simpler. The inventors of the present invention have found that atomic diffusion bonding of pre-polished bonding surfaces results in a robust joint that can withstand the mechanical loads during the use of the component. Unlike [3], the use of atomic diffusion bonding instead of anodic bonding for bonding the plates overcomes the limitation of having few plate materials suitable for bonding. According to the present invention, components may be constructed of the same or different plate materials, for example, with different coefficients of thermal expansion, which are optimized for each application and cannot be manufactured by conventional methods. Components manufactured according to the present invention are electrostatic holders having high-voltage electrodes, constructed in the form of a glass-metal electrode-sapphire or glass-metal electrode-diamond sandwich structure.

[0025] The inventors of the present invention have further found that atomic diffusion bonding also enables the localization of the metal layer as described in [3] without adversely affecting the strength of the joint and without requiring the two plates to consist solely of glass provided for anodic bonding. This result is surprising, as it was previously thought that the joint would be weaker in atomic diffusion bonding and that the glass provided for anodic bonding would have a substantial impact on the transformation of the metal layer. The inventors of the present invention have also found that atomic diffusion bonding can overcome the drawbacks of diffusion bonding under extremely high temperatures and pressures as described in

[12] . The processing performance of atomic diffusion bonding at relatively low temperatures, for example at room temperature, overcomes the limitations on plate materials and combinations of different plate materials.

[0026] In contrast to the situation described in

[13] , the bonding layer of a component manufactured by the present invention performs a dual function in the finished component: firstly, to bond, and secondly, to function as a functional layer, such as an electrode or a resistive heating element. Preferably, the present invention provides a method for processing a metal layer to form a bonding layer, which is therefore embedded in a multilayer component in a sandwich structure, while simultaneously functioning as, for example, a conductive electrode or conductor in the finished component. In this method, the bonding layer required for the joint is converted in some areas into at least one isolator portion.

[0027] After bonding and processing the metal layers, the parts manufactured according to the present invention may undergo further post-processing steps. These post-processing steps may include, for example, heat treatment (tempering) in an electrostatic holding device, and / or adapting the parts to their intended use.

[0028] Heat treatment has the advantage of improving the interdiffusion of atoms in the bonding layer, and therefore strengthening the atomic diffusion junction. Heat treatment has been found to be particularly advantageous, for example, when tungsten is used to form the bonding layer. Heat treatment preferably involves setting the component temperature in the range of 100°C to 300°C, for example, 200°C.

[0029] Adapting a component to its intended use includes, for example, bringing it into contact with a metal layer at the edges of a plate or through holes later created in the plate, and / or further coating the surface of the component.

[0030] According to a preferred embodiment of the present invention, atomic diffusion bonding is carried out at room temperature (e.g., 0°C to 40°C, particularly in the temperature range of about 15°C to 24°C). The temperature of the plates during bonding is at room temperature. A key advantage of performing the process at room temperature is that it is significantly simpler compared to conventional bonding methods performed at high temperatures. Furthermore, since the parts manufactured by the present invention are typically used at room temperature, there is the advantage that there is no temperature change compared to the temperature at which the parts were manufactured, or the change is negligible. This makes it possible to bond plate materials with different coefficients of thermal expansion without adversely affecting the dimensional stability of the parts during use.

[0031] According to another preferred embodiment of the present invention, the pressure between the joining surfaces during plate joining is less than 100,000 Pa. Such relatively low pressure significantly simplifies the execution of the method compared to conventional joining processes, preferably performed by hot pressing. Undesirable effects on the morphological stability of the final joined parts, which may occur due to increased pressure, are avoided. Preferably, atomic diffusion bonding is performed without applying external contact pressure to the plates, for example, by pressing.

[0032] Optionally, a low contact pressure sufficient to prevent air from entering the atomic diffusion junction may be applied. If contact pressure is applied, it is preferably localized to the center of the plate.

[0033] Alternatively, or in addition to this, contact pressure may be applied during atomic diffusion bonding to hold the plates so that a gap is initially created at the outer edge. For example, an external clamp may be provided as a spacer. Preferably, this helps the leading edge of the bond to extend outward from the center of the bond surface without inclusions.

[0034] For example, atomic diffusion bonding is performed with plates stacked together under atmospheric pressure. The upper plate, resting on the lower plate, exerts a gravitational force on the lower plate. Apart from the initiation phase, in which bonding is initiated by a temporary and localized starting pressure (pressure pulse), in the stacked configuration during bonding, the external pressure between the bonding surfaces is preferably formed solely by the gravitational force of the upper plate. The initiation pressure may be generated specifically at the center of the upper plate, for example, by pulsed, manual pressure application. After the start of bonding, no further pressure is applied while the leading edge of the bonding surface progresses from the center of the plate to the edge of the plate.

[0035] According to another preferred feature of the present invention, the bonding surface of the plate is polished to a roughness of less than 1 nm rms, preferably less than 0.8 nm rms, for example less than 0.5 nm rms. The inventors of the present application have found that if the roughness is set lower than the aforementioned limit after the prior polishing of the bonding surface, the mechanical resistance of the joint is substantially improved, particularly continuously across the entire plate surface.

[0036] At least one isolator region can be formed by the oxidation of the metal in the metal layer using oxygen from the adjacent plate material. However, the mechanism for forming this at least one isolator region is not necessarily required. Therefore, according to a preferred modification of the present invention, the material microstructure of the metal contained in the metal layer is altered by the effect of laser irradiation. As a result of the altered material microstructure, the conductivity is lost due to dispersion, particularly in the regions altered by laser irradiation compared to a macroscopically continuous metal material, and at least one isolator region is formed. After bonding, the bonding of the initially continuous metal layer along the interface between the bonding surfaces is converted to an electrically non-conductive structure by laser irradiation. Forming at least one isolator region by generating an electrically insulated structure has the special advantage of overcoming limitations on the selection of plate materials, and the bonding layer may be formed of a non-oxidizing metal such as gold, for example.

[0037] A key advantage of the present invention is the increased diversity in plate material selection. For example, the material limitations in bonding processes used in the prior art are overcome. The plates are preferably made of glass, especially low-ion glass, such as borosilicate glass, especially Eagle XG® (Corning), glass ceramics, crystalline materials, especially sapphire or diamond, ceramics, especially silicon nitride, aluminum nitrite or aluminum oxide, and / or plastics.

[0038] The bonding layers of an atomic diffusion bond may each consist of a single layer or a layer of two or more metallic materials stacked together. The bonding layers may include, for example, gold (see

[14] ), platinum, titanium, silver, and / or tungsten (see

[15] ,

[16] ). If the bonding layers consist of a metal that can react with the surrounding air, in particular, for example, titanium, silver, and / or tungsten, the atomic diffusion bond is preferably carried out under vacuum or in an inert gas to avoid the metal reacting with the environment.

[0039] According to a more advantageous embodiment of the present invention, the two plates joined by atomic diffusion bonding may be made of different materials. Preferably, this allows the plates to have different properties, such as different electrical parameters, depending on the application of the component. For use as an electrostatic holding device, it is particularly preferable that one of the plates be made of a material characterized by a high-voltage breakdown strength of at least 1000 V / mm. The plate with enhanced high-voltage breakdown strength may preferably be provided as a dielectric on the surface of the holding device (e.g., the top surface) on which a semiconductor wafer is held, for example. Alternatively, the plates joined together may contain the same material.

[0040] According to another variation of the present invention, the plates may have the same or different thicknesses. In particular, one plate may be thicker than the other, for example, to form a support plate, and therefore the other plate may be thinner, for example, to form a dielectric for setting the dielectric properties of the retaining device.

[0041] An important feature of the present invention is that the surface of the plates is polished before the formation of the bonding layer and atomic diffusion bonding. The atomic diffusion bonding according to the present invention can preferably be applied to materials that can only be polished to a limited extent, such as ceramic materials. Accordingly, according to another preferred embodiment of the present invention, at least one of the plates on the bonding surface side may have a smooth layer on which the bonding layer of the associated metal is formed. The smooth layer is formed of a material that adheres well to each plate and the bonding layer and can be polished. Preferably, the smooth layer is made of glass or metal with a thickness of 100 nm to 100 μm.

[0042] According to another preferred modification of the present invention, at least one of the plates on the bonding surface side may have at least one adhesion-promoting layer on which a bonding layer of the associated metal is formed. The adhesion-promoting layer is also made of a material that adheres well to the adjacent plate and the bonding layer, and may be made of the same material as the smooth layer, or may be made of titanium or chromium, for example. The adhesion-promoting layer may consist of a single layer or a stack of several layers. The thickness of the adhesion-promoting layer is preferably selected in the range of 5 nm to 100 nm.

[0043] According to another preferred embodiment of the present invention, the following features of a laser irradiation provided to convert a metal layer into at least one isolator section may be provided individually or in combination. Preferably, the laser irradiation has a wavelength such that at least one of the plates is transparent. More preferably, the laser irradiation is used at a wavelength absorbed by the metal layer. Typically, the wavelength of the laser irradiation is selected in the range between ultraviolet (UV) and infrared (IR), and the plate through which the laser irradiation is directed and passed to the metal layer is transparent in the range of the ultraviolet, visible, and / or infrared spectral regions. Furthermore, the laser irradiation may be focused or defocused and directed onto the metal layer. Furthermore, the laser irradiation for locally heating the metal layer is preferably generated by a pulsed laser. The pulsed laser generates the laser irradiation as a series of laser pulses with pulse widths in the range of fs, ps, or ns.

[0044] Preferably, components manufactured by the method according to the present invention have a variety of applications. According to a first preferred application, the component is a carrier for an electrostatic retention device, comprising a bonded plate and including at least one large-area electrode formed by at least one conductive portion and configured to be loaded with a high voltage, wherein at least one isolator portion is positioned adjacent to the at least one electrode. Particularly preferably, the electrostatic retention device comprises at least two large-area electrodes configured to be loaded with a high voltage and separated from each other by at least one isolator portion along an atomic diffusion junction. Preferably, the treatment of the metal layer provided by the present invention further generates at least one conductive track connected to at least one electrode, in addition to at least one electrode. If several electrodes are provided, preferably a conductive track connected to a contact portion is provided to each electrode. The electrodes are connected via the contact portion to a switchable high-voltage supply device.

[0045] According to a second preferred application, the component is a conductive component comprising a joined plate and at least one conductive track formed by at least one conductive portion and configured to load current, wherein at least one isolator portion is positioned adjacent to the at least one conductive track. According to a preferred modification, the conductive component may also comprise at least two conductive tracks, each formed by a conductive portion and separated from each other by at least one isolator portion. A component manufactured according to the present invention may, for example, be a drive device (leading electric field, linear drive) for moving a workpiece by the effect of an alternating electric field. Particularly preferably, in this case as well, the component is formed of two plates joined by an atomic diffusion junction, and the metal layer subjected to the atomic diffusion junction according to the present invention is converted into an electrode arrangement of at least two electrodes having a plurality of electrode regions and / or electrode strips. Alternatively, or in addition thereto, at least one conductive track may be configured as a resistive heating element. In this application, a component manufactured according to the present invention preferably forms at least one electrical resistor, in particular at least one electrically heating resistor. In the method according to the present invention, it is possible to set the size of the metal layer and therefore its electrical surface resistance value. In this case, the plate is preferably made of a material having the same or similar coefficient of thermal expansion.

[0046] As an independent subject of this invention, the component is considered to comprise two plates, both of which are electrically insulated, and at least one of the plates is optically transparent, with at least one flat conductive portion and at least one isolator portion formed between the plates. The plates are joined to each other using an atomic diffusion junction. The atomic diffusion junction is characterized by a metallic layer between the plates, the metallic atoms of which form an intermetallic connection between the metallic layers of the two plates. The at least one flat conductive portion and the at least one isolator portion are formed from the metallic layer contained in the atomic diffusion junction. The at least one isolator portion includes an electrically insulated microstructure that is not metallically conductive.

[0047] Further advantages and details of the present invention are described below with reference to the accompanying drawings. [Brief explanation of the drawing]

[0048] [Figure 1] This is a schematic diagram of a preferred embodiment of the method according to the present invention for manufacturing a component from two plates. [Figure 2] This is a schematic diagram of the processing of a metal layer embedded between two plates, as provided by the present invention. [Figure 3] This is a schematic top view of an electrostatic retention device manufactured by the method according to the present invention. [Figure 4] This is a schematic top view of the electrode arrangement for a non-contact drive device manufactured by the method according to the present invention. [Figure 5] This is a schematic top view of an electrically heated resistor manufactured by the method according to the present invention. [Modes for carrying out the invention]

[0049] Preferred features of embodiments of the method according to the present invention, and the parts manufactured by this method, will be described below with reference to the preparation of the plate, the manufacture of the parts by atomic diffusion bonding, and the treatment of the metal layer at the atomic diffusion bonding. Details of the treatment of the metal layer may be carried out as described in [3]. Accordingly, with respect to the features of the treatment of the metal layer, [3] is incorporated into this disclosure by reference. The complete structure and application details of the parts manufactured by the present invention, for example as electrostatic holders, will not be described to the extent that they are known to those skilled in the art.

[0050] Referring to Figure 1, before manufacturing a component by atomic diffusion bonding, a preparation step S1 is performed, and the prepared bonding surface is provided on the plate. In detail, preparation step S1 includes setting the flatness and roughness of the plate surface provided on the bonding surface by polishing the plate body and cleaning the polished surface. Optionally, a smooth layer may be formed first on the surface of the plate intended for bonding, and the smooth layer is polished. Before polishing, the surface may be lapped. The roughness of the substrate layer is RMS < 1 nm, preferably < 0.8 nm, for example, in the range of 0.5 nm to 0.8 nm, or sometimes < 0.5 nm. Subsequently, the polished surface is covered with a bonding layer. The bonding layer may be a single layer or a stack of, for example, a titanium layer (e.g., 5 nm thick) and a gold layer (e.g., 30 nm thick). The bonding layer is formed, for example, by deposition from the gas phase. Optionally, an adhesion-promoting layer may be formed on the polished surface of the plate before the deposition of the bonding layer. Alternatively, or in addition to the above, plasma treatment may be performed before and / or after the deposition of the bonding layer. If the bonding layer is not made of gold, plasma treatment is preferably performed, for example, with argon plasma.

[0051] Subsequently, in bonding step S2, atomic diffusion bonding of the prepared plates is performed. The covered surfaces of the plates each form a bonding surface. For example, the exposed surface of the bonding surface of one plate, made of gold, comes into contact with the exposed surface of the other plate, also made of gold. In atomic diffusion bonding, one plate is stacked on top of the other, and as a result, their shapes are aligned with each other. If atomic diffusion bonding does not spontaneously begin by mutual contact, a localized starting pressure may be temporarily applied to the plates, either manually or using an appropriate tool, to initiate atomic diffusion bonding. Starting from at least one position where the plates begin to bond, at least one bonding leading edge progresses along the interface between the bonding surfaces until the two plates are bonded together. As a result of bonding step S2, the plates are fixedly bonded together, and the bonding layer forms a metallic layer embedded between the plates.

[0052] As shown in Figure 1, a further method is provided in which an embedded metal layer is constructed, in a construction step S3. The construction of the metal layer is illustrated in the schematic cross-sectional view of Figure 2, showing a metal layer 1 embedded in component 2 and converted into an isolator portion 3 by the effect of focused laser irradiation 4. Component 2 includes two plates 5 and 6, the lower plate 5 comprising an insulating material, such as glass or sapphire, and having a thickness of, for example, 0.1 mm to 5 mm. The upper plate 6 is made of glass with a preferred high dielectric constant, such as Eagle XG glass (manufactured by Corning), with a thickness of, for example, 0.1 mm. The metal layer 1 is made of gold with a thickness of, for example, 30 nm.

[0053] To convert the metal layer 1 into an isolator portion 3, a laser beam 4 is directed onto the metal layer 1. The laser beam 4 may be focused onto the metal layer 1. Focused irradiation may be particularly advantageous for setting a high conversion temperature and forming an isolator portion with high spatial resolution. Alternatively, unfocused irradiation may be performed. If the intensity of the laser beam 4 is sufficient to achieve the desired conversion temperature, then a larger isolator portion may be formed than with focused irradiation. To form a strip-shaped isolator portion 3 with a specific width, an irradiation field with a diameter equal to the desired irradiation width may be generated by defocusing. By moving the laser beam 4 relative to the carrier 2, the metal layer 1 is converted into an isolator portion 3 along the desired strip path. If the intensity of the laser beam 4 is insufficient to set a sufficiently high conversion temperature in the irradiation field of the metal layer 1, multiple irradiations may be used to convert a desired area of ​​the metal layer 1 into an isolator portion 3.

[0054] The laser irradiation power is selected and, optionally, defocusing on the metal layer 1 is selected so that a desired conversion temperature is achieved in the metal layer 1. The conversion temperature depends on the metal in the metal layer 1 and the thickness of the metal layer 1, and is, for example, in the range of 1000°C to 15000°C. Knowing the conversion temperature is not necessarily required. Rather, to carry out the present invention, it is sufficient to set the laser irradiation 4 (intensity and / or beam diameter on the metal layer 1) so that the desired conversion of the metal layer 1 occurs. This setting can be achieved by those skilled in the art by simple tests or by estimating the temperature of the metal layer that absorbs the laser irradiation on the surface of the carrier.

[0055] In the further method shown in Figure 1, the functionalization step S4 is performed, and the component is completed according to its actual function. For example, to manufacture an electrostatic holding device, electrodes may be brought into contact, another layer deposited, and / or another plate bonded.

[0056] Preferably, the preparation step S1 and / or the functionalization step S4 are steps of a method according to the present invention. In this case, the plates are joined and the metal layer is processed immediately after the preparation of the plates, and / or the part is completed immediately after the metal layer is constructed. However, steps S1 and S4 are not necessarily part of a method according to the present invention. For example, the preparation step S1 may be performed independently of a later step of a method according to the present invention, i.e., the method according to the present invention is carried out on individually provided prepared plates. Furthermore, the functionalization step S4 may be performed independently of a preceding step of a method according to the present invention, in which case the joined and constructed part is provided as a semi-finished product for further processing.

[0057] The method according to the present invention was performed as a test using the following example. Two polished circular quartz glass wafers (type POT721, 10218000, DSP TTV < 10 μm, Ra < 0.5 nm, manufactured by Nano Quarz Wafer GmbH) with a diameter of 76.2 mm and a thickness of 0.5 mm ± 0.2 mm were used as plates. The quartz glass wafers were coated on one side first with 5 nm of Ti and then with 30 nm of Au in an ion beam evaporation plant. The roughness of the bonding surface was determined to be approximately rms = 0.5 nm using an atomic force microscope (measurement field of view 1 × 1 μm). The quartz glass wafers were taken from the coating plant immediately after coating and bonded to each other along the bonding surface at room temperature by atomic diffusion bonding.

[0058] For bonding, the quartz glass wafers were stacked with the bonding surface, i.e., the gold side, facing each other, and an initial starting pressure was applied. The bonding leading edge propagated similarly to the optical contact bonding process. In contrast to bonding by optical contact bonding, the bond in the described example exhibited high mechanical resistance. Repeated high-energy treatments in an ultrasonic bath (frequency 40 kHz, surfactant bath) could not separate the bond between the quartz glass wafers. Furthermore, applying a razor blade to the side of the joint could not completely separate the bonded portions. This result corresponds to experiments using atomic diffusion bonding, where compressive shear strengths of up to 70 MPa were measured (see

[14] ).

[0059] A bonding layer, formed by creating a metal layer between quartz glass wafers, was then constructed using laser irradiation. Laser irradiation was performed using a diode-excited Nd:YAG-ns pulsed laser (e.g., wavelength 355 nm, 50 mW, spot width 7 μm, overlap rate >95% between irradiation points, scanning the metal layer linearly). A strip-shaped isolator region with a width of 0.7 mm was generated. The isolator region was formed by several lines with a 50% overlap rate where laser irradiation was performed. A key advantage of this invention is that the processing of the metal layer did not negatively affect the bonding layer, and only the isolator region was generated. The isolator region had a high-voltage breakdown strength exceeding 30 kV. The mechanical strength of the bonding layer was maintained even after processing the metal layer.

[0060] Figure 3 schematically shows a top view of an example of a component manufactured in the form of an electrostatic retaining device 10 by the method according to the present invention. The electrostatic retaining device 10 comprises two plates connected to each other by atomic diffusion junction. A metal layer 1 is embedded between the plates and constructed as shown in Figure 2. In the method according to the present invention, an isolator portion 3 is formed within the metal layer 1 in the form of an annular 3.1 with a band portion 3.2 running laterally within the annular 3.1. This divides the metal layer 1 into two electrodes 1.1 and 1.2, each in the form of a semicircular region, and an annular electrode 1.3. The diameter of the plate is, for example, 30 cm. The width of the isolator portion 3 along the annular 3.1 and along the band portion 3.2 is, for example, 150 μm. The width of the annular electrode 1.3 is, for example, 10 mm.

[0061] Electrodes 1.1, 1.2, and 1.3 are completely covered by an upper plate (e.g., plate 6 in Figure 2), and as a result, electrically insulated from the environment. Furthermore, electrodes 1.1, 1.2, and 1.3 are insulated from each other by an isolator section 3. Contact holes 7.1, 7.2, and 7.3 are formed in the upper plate to contact electrodes 1.1, 1.2, and 1.3, through which electrodes 1.1, 1.2, and 1.3 can be electrically connected to the power supply unit 20. For example, contact holes 7.1, 7.2, and 7.3, with a diameter of 500 μm, are formed, for example, by etching the upper glass component with hydrofluoric acid (HF). Contact holes 7.1, 7.2, and 7.3 are etched using a film mask. The metal layer 1 acts as an etching stopper during etching. As an alternative to etching, contact holes 7.1, 7.2, and 7.3 are mechanically generated in the upper plate by drilling or grinding.

[0062] The power supply unit 20 includes a high-voltage supply source configured to load positive or negative high voltages onto electrodes 1.1 and 1.2, respectively, and to connect the annular electrode 1.3 to ground potential.

[0063] The electrostatic holding device 10 further comprises a holding device and / or a driving device used for transferring a workpiece, such as a semiconductor wafer, which are formed as in conventional electrostatic holding devices and are not shown in Figure 3.

[0064] Figure 4 shows a schematic top view of a traveling wave drive device 11 as another example of a component manufactured by the method according to the present invention. The traveling wave drive device 11 is configured to move a workpiece by the effect of a traveling electric field. In this example as well, the two plates are manufactured by atomic diffusion bonding through an intermediate bonding layer. In the embodiment of Figure 4, the bonding layer forms a metal layer 1 and is constructed as an electrode arrangement having two comb-tooth electrodes 1.4 and 1.5. In the method according to the present invention, an isolator section 3 is formed, consisting of a meandering section 3.3 and a rectangular strip frame 3.4. The electrodes 1.4 and 1.5 are in contact through contact holes 7.1 and 7.2 in the upper plate, respectively, and are connected to a power source (not shown). The comb-tooth electrodes 1.4 and 1.5 are formed by interlocking strip electrode fingers and may be loaded with alternating voltages having opposite polarities. As a result, by using electrodes 1.4 and 1.5, a traveling electric field can be generated adjacent to the traveling wave driving device 11, and as a result, the workpiece, such as a semiconductor wafer, can be moved on the gas bed.

[0065] The implementation of the present invention is not limited to the illustrated electrode arrangement layout, but may be modified depending on the actual application of the invention, for example, according to the desired orientation of the field effect.

[0066] Figure 5 shows another example of a component manufactured according to the present invention that forms an electrically heated resistor 12. A metal layer 1 embedded between plates is constructed to form a predetermined electrical resistance for resistive heating. The heated resistor 12 comprises two plates joined by an atomic diffusion junction, the junction layer providing the metal layer 1. In the method according to the present invention, the isolator portion 3 is shaped to form a meandering electrode 1.6. The width of the isolator portion 3 can set the surface resistance of the electrode 1.6 and thus, for example, the heating force of the heated resistor.

[0067] The features of the present invention disclosed in the above description, drawings, and claims may be suitable, both individually and in combination, for implementing the invention in various embodiments. [Explanation of symbols]

[0068] 1 metal layer 1.1, 1.2 electrode 1.3 Annular electrode 1.4, 1.5 comb electrode 1.6 Serpentine electrodes 2. Components (carriers) 3. Isolator section 3.1 Ring 3.2 Band 3.3 Meandering section 3.4 Strip-shaped frame 4. Laser irradiation 5. Lower plate 6. Upper plate 7.1, 7.2, 7.3 Contact hole 10 Electrostatic holding device 11. Traveling wave drive device 12 Heat-generating resistor 20 Power supply

Claims

1. A method for manufacturing parts (2, 10, 11, 12) from two plates (5, 6), wherein both plates (5, 6) are electrically insulated, at least one of the plates (5, 6) is optically transparent, and at least one flat conductive portion and at least one isolator portion (3) are formed between the plates (5, 6). The aforementioned method, A step of joining plates (5, 6) at opposing joining surfaces, wherein a metal layer (1) is placed between the plates (5, 6), A step of processing the metal layer (1) by locally heating the metal layer (1) using laser irradiation (4) so ​​that the metal layer (1) is converted in some area into the at least one isolator portion (3), wherein the at least one conductive portion is formed adjacent to the at least one isolator portion (3), and the optical path of the laser irradiation (4) and the components (2, 10, 11, 12) are moved relative to each other when forming the at least one isolator portion (3) in order to convert the metal layer (1) into the at least one isolator portion (3) across a line or area, The plates (5, 6) have their joining surfaces polished, and the joining surfaces are formed by a metal bonding layer. The bonding of the plates (5, 6) includes an atomic diffusion bonding, and the metal bonding layer forms the metal layer (1) between the bonded plates (5, 6). The metal layer (1) has a thickness of 20 nm or more and 1 μm or less. A method characterized by the following features.

2. The method according to claim 1, wherein the atomic diffusion bonding is carried out at room temperature.

3. The method according to claim 1 or 2, wherein the bonding surface side of the plates (5, 6) is polished to a roughness of less than 1 nm rms.

4. The method according to any one of claims 1 to 3, wherein, while the metal layer (1) is being treated by locally heating the metal layer (1), the metal contained in the metal layer (1) changes within the material microstructure due to the effect of the laser irradiation (4) so ​​as to form the at least one isolator portion (3).

5. The method according to any one of claims 1 to 4, wherein the plates (5, 6) are made of different materials.

6. The method according to any one of claims 1 to 5, wherein one of the plates (5, 6) is made of a material having a high voltage breakdown strength of at least 1000 V / mm.

7. The method according to any one of claims 1 to 6, wherein the plates (5, 6) are made of at least one of glass, glass ceramic, and crystalline material.

8. The method according to any one of claims 1 to 7, wherein at least one of the plates (5, 6) has a smooth layer on the joining surface side on which the associated metal bonding layer is formed.

9. The method according to any one of claims 1 to 8, wherein at least one of the plates (5, 6) has at least one adhesion promoting layer on the joining surface side on which the associated metal bonding layer is formed.

10. The metal layer (1) is characterized in that it is locally heated by the laser irradiation (4) at a wavelength such that at least one of the plates (5, 6) is transparent. The metal layer (1) is characterized in that it is locally heated by the focused or off-focus laser irradiation (4), and A key feature is that the laser irradiation (4) that locally heats the metal layer (1) is generated by a pulsed laser. The method according to any one of claims 1 to 9, comprising at least one of the above.

11. The component is a carrier for an electrostatic retention device (10), which includes the joined plates (5, 6) and includes at least one large-area electrode formed by the at least one conductive portion and configured to be subjected to a high voltage load. The method according to any one of claims 1 to 10, wherein the at least one isolator portion (3) is arranged adjacent to the at least one electrode.

12. The electrostatic retention device (10) is characterized by including at least two electrodes, each formed by a conductive portion and separated from each other by at least one isolator portion (3), and The processing of the metal layer (1) using laser irradiation (4) is characterized by including the generation of at least one conductive track connected to the at least one electrode. The method according to claim 11, comprising at least one of the following.

13. The component is a conductor component (11, 12) which includes the joined plates (5, 6) and includes at least one conductor track formed by the at least one conductor portion and configured to load current, The method according to any one of claims 1 to 10, wherein the at least one isolator portion (3) is arranged adjacent to the at least one conductor track.

14. The conductor components (11, 12) are characterized in that each includes at least two conductor tracks, each formed by a conductor portion and separated from each other by at least one isolator portion (3), and The characteristic feature is that at least one of the conductor tracks is configured as a drive device (11) for moving a workpiece by the effect of an alternating electric field, or as a heating resistor (12). The method according to claim 13, comprising at least one of the following.

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