CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of U.S. Provisional Patent Application Number

62/742,009, which was filed on October 5, 2018, and which is incorporated herein in its entirety by reference.

FIELD

[0002] The present disclosure relates to internal heating for bonding apparatuses, for example, a bonding apparatus for lithography apparatuses and systems.

BACKGROUND

[0003] A lithographic apparatus is a machine constructed to apply a desired pattern onto a substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A lithographic apparatus may, for example, project a pattern of a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) provided on a substrate.

[0004] To project a pattern on a substrate a lithographic apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features which can be formed on the substrate. A lithographic apparatus, which uses extreme ultraviolet (EUV) radiation, having a wavelength within the range 4-20 nm, for example 6.7 nm or 13.5 nm, may be used to form smaller features on a substrate than a lithographic apparatus which uses, for example, radiation with a wavelength of 193 nm.

[0005] The joining together of pieces of material is a common operation for most manufacturing processes, including lithographic processes. The use of epoxies or adhesive materials to attach together components in lithographic and semiconductor manufacturing processes is known in the art. Current methods to bond components with epoxy or other adhesives require setting a bond line with glass beads, wires, or machined features, and heating the epoxy by convection (e.g., a heat gun) or induction to form the bond. Heat can later be applied to debond the epoxy and the components can then be separated.

[0006] However, convection and induction methods are difficult for debonding components located in low accessibility areas. Moreover, temperature sensitive components (e.g., magnets) or other nearby bonded areas can be affected by the large temperature gradient caused by convection and induction heating methods. Because of the advantages and versatility of epoxy or adhesive bonding, there is a need to bond pieces with epoxy and later debond the pieces without damaging the bonded pieces and/or sensitive components located nearby in a convenient and efficient manner.

SUMMARY

[0007] In some embodiments, a bonding apparatus includes a first substrate, a second substrate, a bonding layer, and a heating element. In some embodiments, the bonding layer is disposed between the first and second substrates. In some embodiments, the bonding layer is configured to bond the first and second substrates together. In some embodiments, the heating element is disposed between the first and second substrates. In some embodiments, the heating element contacts the bonding layer. In some embodiments, the heating element is configured to generate localized resistive heating to bond the first and second substrates together. In some embodiments, the heating element is configured to generate localized resistive heating to debond the first and second substrates apart.

[0008] In some embodiments, the heating element includes a frame and a resistive wire integral with the frame. In some embodiments, the frame has a substantially uniform thickness and is configured to set a predetermined bond line thickness of the bonding layer. In some embodiments, the frame has a stiffness, a compression strength, or a coefficient of thermal expansion substantially equivalent to that of the bonding layer. In some embodiments, the resistive wire includes nichrome. In some embodiments, the resistive wire includes a single preformed resistive wire configured to cover a majority of a bond area between the first and second substrates. In some embodiments, the single preformed resistive wire is arranged in a serpentine, zigzag, spiral, or coil pattern. In some embodiments, the frame includes a groove configured to ventilate the bonding layer.

[0009] In some embodiments, the heating element includes an insulated resistive wire integral with the bonding layer. In some embodiments, the bonding layer comprises an epoxy, elastomer, or thermoplastic. In some embodiments, the first substrate is magnetic. In some embodiments, the localized resistive heating is such that any heat transferred to the first substrate is less than 40 °C. In some embodiments, the localized resistive heating is such that any heat transferred to the second substrate is less than 40 °C. In some embodiments, the localized resistive heating is such that any heat transferred to the first and second substrates is less than 40 °C.

[0010] In some embodiments, a heating apparatus for bonding or debonding a first substrate and a second substrate includes a frame and a resistive wire. In some embodiments, the resistive wire is integral with the frame. In some embodiments, the resistive wire is configured to generate localized resistive heating in a bonding layer between the first and second substrates. In some embodiments, the localized resistive heating is such that any heat transferred to the first and second substrates is less than 40 °C.

[0011] In some embodiments, the frame has a substantially uniform thickness and is configured to set a predetermined bond line thickness of the bonding layer. In some embodiments, the frame has a stiffness, a compression strength, or a coefficient of thermal expansion substantially equivalent to that of the bonding layer. In some embodiments, the frame includes a groove configured to ventilate the bonding layer. In some embodiments, the frame includes a plastic, thermoplastic, ceramic, or metal.

[0012] In some embodiments, a method for bonding or debonding a first substrate and a second substrate includes bonding the first and second substrates to form a bonding apparatus, passing an electrical current through the bonding apparatus that generates localized resistive heating in the bonding apparatus, and separating the first and second substrates apart. In some embodiments, the bonding apparatus includes a bonding layer disposed between the first and second substrates and a heating element disposed between the first and second substrates. In some embodiments, the heating element contacts the bonding layer. In some embodiments, the method includes passing an electrical current through the heating element that generates localized resistive heating in the bonding layer. In some embodiments, the localized resistive heating is such that any heat transferred to the first and second substrates is less than 40 °C.

[0013] In some embodiments, the method includes passing an electrical current through the heating element that generates localized resistive heating and promotes bond curing of the bonding layer. In some embodiments, the method includes applying a force of less than 15 N, a torque of less than 10 Nm, or gravity to separate the first and second substrates.

[0014] Further features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying drawings. It is noted that the invention is not limited to the specific embodiments described herein. Such embodiments are presented herein for illustrative purposes only. Additional embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

[0015] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the relevant art(s) to make and use the invention. Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:

[0016] FIG. 1 is a schematic illustration of a lithographic apparatus, according to an exemplary embodiment;

[0017] FIG. 2 is a perspective schematic illustration of a bonding apparatus in a bonded configuration, according to an exemplary embodiment;

[0018] FIG. 3 is a cross-sectional view of the bonding apparatus of Figure 2;

[0019] FIGS. 4A-4D are schematic illustrations of a heating element in plan view, according to exemplary embodiments;

[0020] FIG. 5 is a perspective schematic illustration of a bonding apparatus in a debonded configuration, according to an exemplary embodiment; and

[0021] FIG. 6 is a cross-sectional view of the bonding apparatus of Figure 5.

[0022] The features and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. Additionally, generally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears. Unless otherwise indicated, the drawings provided throughout the disclosure should not be interpreted as to-scale drawings.

DETAIFED DESCRIPTION

[0023] This specification discloses one or more embodiments that incorporate the features of this invention. The disclosed embodiment(s) merely exemplify the invention. The scope of the invention is not limited to the disclosed embodiment(s). The invention is defined by the claims appended hereto.

[0024] The embodiment(s) described, and references in the specification to “one embodiment,”“an embodiment,”“an example embodiment,” etc., indicate that the embodiment(s) described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is understood that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0025] Spatially relative terms, such as “beneath,” “below,”“lower,” “above,”“on,”

“upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.

[0026] The term“about” as used herein indicates the value of a given quantity that can vary based on a particular technology. Based on the particular technology, the term“about” can indicate a value of a given quantity that varies within, for example, 10-30% of the value (e.g., ±10%, ±20%, or ±30% of the value).

[0027] The term“substantially” as used herein indicates the value of a given quantity that can vary based on a particular technology. Based on the particular technology, the term “substantially” can indicate a value of a given quantity that varies within, for example, 0-10% of the value (e.g., ±1%, ±2%, or ±10% of the value).

[0028] Embodiments of the disclosure may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the disclosure may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustical or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others. Further, firmware, software, routines, and/or instructions may be described herein as performing certain actions. However, it should be appreciated that such descriptions are merely for convenience and that such actions in fact result from computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc., and in doing that may cause actuators or other devices to interact with the physical world.

[0029] Before describing such embodiments in more detail, however, it is instructive to present an example environment in which embodiments of the present disclosure may be implemented.

[0030] Exemplary Lithographic System

[0031] FIG. 1 shows a lithographic system comprising a radiation source SO and a lithographic apparatus LA. The radiation source SO is configured to generate an EUV radiation beam B and to supply the EUV radiation beam B to the lithographic apparatus LA. The lithographic apparatus LA comprises an illumination system IL, a support structure MT configured to support a patterning device MA (e.g., a mask), a projection system PS, and a substrate table WT configured to support a substrate W.

[0032] The illumination system IL is configured to condition the EUV radiation beam B before the EUV radiation beam B is incident upon the patterning device MA. Thereto, the illumination system IL may include a facetted field mirror device 10 and a facetted pupil mirror device 11. The faceted field mirror device 10 and faceted pupil mirror device 11 together provide the EUV radiation beam B with a desired cross-sectional shape and a desired intensity distribution. The illumination system IL may include other mirrors or devices in addition to, or instead of, the faceted field mirror device 10 and faceted pupil mirror device 11.

[0033] After being thus conditioned, the EUV radiation beam B interacts with the patterning device MA. As a result of this interaction, a patterned EUV radiation beam B’ is generated. The projection system PS is configured to project the patterned EUV radiation beam B’ onto the substrate W. For that purpose, the projection system PS may comprise a plurality of mirrors 13, 14 which are configured to project the patterned EUV radiation beam B’ onto the substrate W held by the substrate table WT. The projection system PS may apply a reduction factor to the patterned EUV radiation beam B’, thus forming an image with features that are smaller than corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 may be applied. Although the projection system PS is illustrated as having only two mirrors 13, 14 in FIG. 1, the projection system PS may include a different number of mirrors (e.g. six or eight mirrors).

[0034] The substrate W may include previously formed patterns. Where this is the case, the lithographic apparatus FA aligns the image, formed by the patterned EUV radiation beam B’, with a pattern previously formed on the substrate W.

[0035] A relative vacuum, i.e. a small amount of gas (e.g. hydrogen) at a pressure well below atmospheric pressure, may be provided in the radiation source SO, in the illumination system IF, and/or in the projection system PS.

[0036] The radiation source SO may be a laser produced plasma (FPP) source, a discharge produced plasma (DPP) source, a free electron laser (FEE), or any other radiation source that is capable of generating EUV radiation.

[0037] Exemplary Bonding Apparatuses

[0038] Epoxy adhesives are a type of structural adhesive, and can be used to bond metals, glasses, ceramics, magnets, plastics, and other materials. Epoxies cured with heat will be more heat- and chemical-resistant than those cured at room temperature. The joining together of pieces of material is an operation used by manufacturing processes, including lithographic processes. The use of epoxies to attach together components in lithographic and semiconductor manufacturing processes can be used to repair or replace specific bonded components. Current methods to bond components with epoxy or other adhesives require setting a bond line with glass beads, wires, or machined features, and heating the epoxy by convection (e.g., a heat gun) or induction to form the bond. Heat can later be applied to debond the epoxy and the components can then be separated with an applied force or torque.

[0039] However, convection and induction methods are difficult for bonding or debonding components located in low accessibility areas. For example, selective debonding for some applications requires the additional step of removing or debonding other bonded components to physically access the selected component under investigation. Moreover, temperature sensitive components (e.g., magnets) or other nearby bonded areas can be affected by the large non-localized temperature gradient caused by convection and induction heating methods. For example, temperatures exceeding 40 °C can cause permanent damage to certain magnets (e.g., complete loss of magnetic field) and weaken the overall magnetic strength of other magnets. Further, large applied forces or torques, for example, exceeding 15 N or 10 Nm, to the bonded components can cause damage to the components even after heat is applied to debond the epoxy.

[0040] Resistive heating or Joule heating is a type of thermal conduction in which an electric current is passed through a conductor (e.g., resistive wire) to produce heat. The heat produced is proportional to the square of the current applied and the electrical resistance of the conductor. Resistive wire can be formed into various shapes and sizes for a variety of bond surfaces and bond areas. For example, resistive wire can be wound in planar coils to obtain a certain electrical resistance and temperature gradient. Nichrome (NiCr) is a type of resistive heating wire alloy, composed of nickel, chromium, and sometimes iron alloys. NiCr is corrosion-resistant, stable at high temperatures, and can be manufactured at a low cost.

[0041] A single piece of resistive wire, for example, NiCr, can be disposed in an epoxy for full coverage of the bond area and bond surface. Localized bonding and debonding can be conducted through resistive heating of the resistive wire in the bond area. Resistive heating and debonding transfers heat to bonded component surfaces at lower temperatures (e.g., 30 °C) compared to alternative convective or inductive heating temperatures (e.g., 80 °C). The localized resistive heating can prevent damage to temperature sensitive components, for example, magnets (e.g., NIB, rare-earth, etc.) or other nearby bonded components. Further, the localized resistive heating can promote bond curing for faster and controlled bonding. Repairs or replacements of bonded components can be localized, reliable, convenient, and faster compared to current convection and induction methods.

[0042] FIGS. 2 and 3 show schematic illustrations of an exemplary bonding apparatus 200, according to some embodiments of this disclosure. Bonding apparatus 200 can include first substrate 202, second substrate 204, bonding layer 206, and heating element 300. In some embodiments, bonding apparatus 200 can be implemented in lithographic apparatus LA. For example, bonding apparatus 200 can be used to bond a motor for support structure MT in lithographic apparatus LA.

[0043] First substrate 202 can be any shape or size and any material. For example, first substrate 202 can be a magnet for support structure MT in lithographic apparatus LA. In some embodiments, first substrate 202 can be a metal, an insulator, a ceramic, a magnetic material, a glass, an optic, or any other suitable material that can be bonded by epoxy or adhesive. Second substrate 204 can be any shape or size and any material. For example, second substrate 204 can be a glass optic for illumination system IL in lithographic apparatus LA. In some embodiments, second substrate 204 can be a metal, an insulator, a ceramic, a magnetic material, a glass, an optic, or any other suitable material that can be bonded by epoxy or adhesive. In some embodiments, first substrate 202 can be a metal while second substrate 204 can be a ceramic (e.g., glass, ZERODUR®, etc.). In some embodiments, second substrate 204 can be a metal while first substrate 202 can be a ceramic (e.g., glass, ZERODUR®, etc.). In some embodiments, first and second substrates 202, 204 can be the same material, for example, a metal or a glass.

[0044] As shown in FIGS. 2 and 3, bonding layer 206 can be disposed between first substrate 202 and second substrate 204. In some embodiments, bonding layer 206 can be configured to bond first and second substrates 202, 204 together. As shown in FIGS. 2 and 3, bonding apparatus 200 can be in a bonded configuration 20, such that first and second substrates 202, 204 are bonded together by bonding layer 206. In some embodiments, bonding layer 206 can extend between first and second substrates 202, 204 around heating element 300. In some embodiments, bonding layer 206 is an epoxy, elastomer, or thermoplastic. For example, bonding layer 206 can be a thermally cured epoxy.

[0045] Heating element 300 can be disposed between first and second substrates 202, 204.

Heating element 300 contacts bonding layer 206. In some embodiments, heating element 300 can be integral with bonding layer 206. For example, heating element 300 can be embedded in bonding layer 206. Heating element 300 generates localized resistive heating when an electric current is passed through heating element 300. In some embodiments, heating element 300 is configured to generate localized resistive heating to bond first and second substrates 202, 204 together. For example, the localized resistive heating generated by heating element 300 promotes bond curing of bonding layer 206. In some embodiments, heating element 300 is configured to generate localized resistive heating to debond first and second substrates 202, 204 apart. For example, the localized resistive heating generated by heating element 300 is such that bonding layer 206 is cohesively debonded from first and second substrates 202, 204 and any heat transferred to the first and second substrates is less than 40 °C.

[0046] As shown in FIGS. 2 and 3, heating element 300 can include resistive wire 308. In some embodiments, resistive wire 308 can include NiCr. For example, resistive wire 308 can be 90% nickel and 10% chromium, by mass, with a wire thickness of 125 microns. In some embodiments, as shown in FIG. 2, heating element 300 can include first lead 302 and second lead 304, which each are electrically connected to resistive wire 308. In some embodiments, resistive wire 308 can be insulated resistive wire 310. For example, insulated resistive wire 310 can be NiCr with an 8 micron thick polyimide insulation layer. In some embodiments, heating element 300 can include insulated resistive wire 310 integral with bonding layer 206. For example, as shown in FIG. 4D, heating element 300 can be insulated resistive wire 310 with first and second leads 302, 304. In some embodiments, insulated resistive wire 310 can be embedded in bonding layer 206.

[0047] In some embodiments, as shown in FIGS. 2 and 3, heating element 300 can include frame 306 with resistive wire 308 integral with frame 306. For example, resistive wire 308 can be embedded in frame 306. Frame 306 can be any suitable shape or size and any material to help bond or debond first and second substrates 202, 204. In some embodiments, frame 306 can be a thin quadrilateral or cuboid. In some embodiments, frame 306 can be a thin disk or cylinder. In some embodiments, frame 306 can be an insulator, for example, a plastic. In some embodiments, frame 306 can be a metal, for example, titanium. In some embodiments, frame 306 can be configured to set or control a predetermined bond line thickness of bonding layer 206. For example, frame 306 can have a substantially uniform thickness (height) in order to form a substantially uniform bonding layer 206 thickness, for example, 0.5 mm between first and second substrates 202, 204. In some embodiments, frame 306 can be configured to ventilate bonding layer 206. For example, as shown in FIGS. 2 and 3, frame 306 can include first groove 312 and second groove 314, each extending along one or more surfaces of frame 306, to help ventilate and evenly flow bonding layer 206 between heating element 300 and first and second substrates 202, 204. In some embodiments, frame 306 can have a stiffness, a compression strength, or a coefficient of thermal expansion substantially equivalent to that of bonding layer 206. For example, the stiffness of frame 306 can be tuned to substantially match bonding layer 206 such that both frame 306 and bonding layer 206 compress or flex about or substantially the same amount during bonding or debonding.

[0048] In some embodiments, as shown in FIGS. 2 and 3, resistive wire 308 can be disposed along a plane of symmetry of frame 306. For example, as shown in FIG. 3, the plane of symmetry can be along a height centerline of frame 306. In some embodiments, resistive wire 308 can be bare (uninsulated) and integral with frame 306. For example, resistive wire 308 can be bare NiCr and frame 306 can be an insulating high-temperature thermoplastic. In some embodiments, resistive wire 308 can be insulated resistive wire 310. For example, as shown in FIG. 4D, resistive wire 308 can be bare (uninsulated) and encased in an insulator to form insulated resistive wire 310.

[0049] FIGS. 4A through 4D show schematic illustrations of exemplary heating element

300, according to some embodiments of this disclosure. In some embodiments, as shown in FIGS. 4A through 4C, heating element 300 can include frame 306 and resistive wire 308 integral with frame 306, with first and second leads 302, 304 electrically connected to resistive wire 308 and extending external to frame 306. For example, resistive wire 308 can be embedded in frame 306. In some embodiments, resistive wire 308 can be a single preformed resistive wire. For example, as shown in FIGS. 4A through 4D, resistive wire 308 can be shaped to maximize coverage or cover a majority of a bond area or a cross-sectional area of frame 306 between first and second substrates 202, 204. In some embodiments, resistive wire 308 can be arranged in a serpentine pattern. For example, as shown in FIG. 4A, resistive wire 308 is shaped like a serpentine, with first and second leads 302, 304 at each end. In some embodiments, resistive wire 308 can be arranged in a spiral pattern. For example, as shown in FIG. 4B, resistive wire 308 is shaped like a square spiral, with first and second leads 302, 304 at each end. In some embodiments, resistive wire 308 can be arranged in a coil pattern. For example, as shown in FIG. 4C, resistive wire 308 is shaped like a circular coil, with first and second leads 302, 304 at each end. In some embodiments, resistive wire 308 can be arranged in a zigzag pattern. For example, as shown in FIG. 4D, insulated resistive wire 310 is shaped like a zigzag, with first and second leads 302, 304 at each end. In some embodiments, frame 306 can be omitted and insulated resistive wire 310 can be heating element 300 and integral with bonding layer 206. For example, as shown in FIG. 4D, heating element 300 can include insulated resistive wire 310. In some embodiments, insulated resistive wire 310 can be embedded in bonding layer 206.

[0050] FIGS. 5 and 6 show schematic illustrations of an exemplary bonding apparatus 200, according to some embodiments of this disclosure. As shown in FIGS. 5 and 6, bonding apparatus 200 can be in a debonded configuration 30, such that first and second substrates 202, 204 are debonded apart from bonding layer 206. In some embodiments, heating element 300 is configured to generate localized resistive heating to debond first and second substrates 202, 204 apart. For example, the localized resistive heating generated by heating element 300 is such that any heat transferred to first and second substrates 202, 204 is less than 40 °C. Specifically, for a NiCr resistive wire 308, a magnetic first substrate 202, and a steady voltage of 25 V applied to heating element 300 for 240 secs, bonding layer 206 failed cohesively with a maximum magnetic first substrate 202 surface temperature of 33.7 °C and magnetic first substrate 202 was removed with an applied 10 Nm torque.

[0051] Methods of operating a bonding apparatus can be accomplished according to the manners of operation disclosed herein. In some embodiments, as shown in FIGS. 2 and 3, bonding apparatus 200 can be arranged in bonded configuration 20. In some embodiments, this can be accomplished, for example, by applying bonding layer 206 and heating element 300 between first and second substrates 202, 204. In some embodiments, bonded configuration 20 can be accomplished by passing an electrical current through heating element 300 that generates localized resistive heating and promotes bond curing of bonding layer 206. In some embodiments, as shown in FIGS. 5 and 6, bonding apparatus 200 can be arranged in debonded configuration 30. In some embodiments, this can be accomplished, for example, by passing an electrical current through heating element 300 that generates localized resistive heating with a low temperature gradient, for example, such that surface temperatures of first and second substrates 202, 204 near heating element 300 remain less than 40 °C, and separating first and second substrates 202, 204 apart. For example, applying a force of less than 15 N, a torque of less than 10 Nm, or gravity to separate first and second substrates 202, 204.

[0052] In some embodiments, in bonded configuration 20 (see FIGS. 2 and 3), a user can pass an electrical current, for example, 4.1 mA (for V = 25 V and R = 6.094 kQ) for a period of time, for example, 240 secs, through heating element 300 that generates localized resistive heating with a low temperature gradient, for example, a surface temperature of less than 40 °C for first and second substrates 204, 204. The user can then apply a force of less than 15 N, a torque of less than 10 Nm, or gravity to separate first and second substrates 202, 204 apart and achieve debonded configuration 30 (see FIGS. 5 and 6). For example, first and second substrates 202, 204, after debonding, can be separated solely from their own weight and the force of gravity (i.e., no applied force or torque needed).

[0053] The embodiments may further be described using the following clauses:

1. A bonding apparatus comprising:

a first substrate;

a second substrate; a bonding layer disposed between the first and second substrates, wherein the bonding layer is configured to bond the first and second substrates together; and

a heating element disposed between the first and second substrates, wherein the heating element contacts the bonding layer and is configured to generate localized resistive heating to bond the first and second substrates together or to debond the first and second substrates apart.

2. The bonding apparatus of clause 1, wherein the heating element comprises a frame and a resistive wire integral with the frame.

3. The bonding apparatus of clause 2, wherein the frame has a substantially uniform thickness and is configured to set a predetermined bond line thickness of the bonding layer.

4. The bonding apparatus of clause 2, wherein the frame has a stiffness, a compression strength, or a coefficient of thermal expansion substantially equivalent to that of the bonding layer.

5. The bonding apparatus of clause 2, wherein the resistive wire comprises nichrome.

6. The bonding apparatus of clause 2, wherein the resistive wire comprises a single preformed resistive wire configured to cover a majority of a bond area between the first and second substrates.

7. The bonding apparatus of clause 6, wherein the single preformed resistive wire is arranged in a serpentine, zigzag, spiral, or coil pattern.

8. The bonding apparatus of clause 2, wherein the frame comprises a groove configured to ventilate the bonding layer.

9. The bonding apparatus of clause 1, wherein the heating element comprises an insulated resistive wire integral with the bonding layer.

10. The bonding apparatus of clause 1, wherein the bonding layer comprises an epoxy, elastomer, or thermoplastic.

11. The bonding apparatus of clause 1, wherein the first substrate is magnetic.

12. The bonding apparatus of clause 11, wherein the localized resistive heating is such that any heat transferred to the first substrate is less than 40 °C.

13. A heating apparatus for bonding or debonding a first substrate and a second substrate, comprising:

a frame; and

a resistive wire integral with the frame, wherein the resistive wire is configured to generate localized resistive heating in a bonding layer between the first and second substrates,

wherein the localized resistive heating is such that any heat transferred to the first and second substrates is less than 40 °C.

14. The heating apparatus of clause 13, wherein the frame has a substantially uniform thickness and is configured to set a predetermined bond line thickness of the bonding layer.

15. The heating apparatus of clause 13, the frame has a stiffness, a compression strength, or a coefficient of thermal expansion substantially equivalent to that of the bonding layer.

16. The heating apparatus of clause 13, wherein the frame comprises a groove configured to ventilate the bonding layer.

17. The heating apparatus of clause 13, wherein the frame comprises a plastic, thermoplastic, ceramic, or metal.

18. A method for bonding or debonding a first substrate and a second substrate, comprising: bonding the first and second substrates to form a bonding apparatus, the bonding apparatus comprising:

a bonding layer disposed between the first and second substrates; and a heating element disposed between the first and second substrates, wherein the heating element contacts the bonding layer;

passing an electrical current through the heating element that generates localized resistive heating in the bonding layer, wherein the localized resistive heating is such that any heat transferred to the first and second substrates is less than 40 °C; and

separating the first and second substrates apart.

19. The method of clause 18, further comprising passing an electrical current through the heating element that generates localized resistive heating and promotes bond curing of the bonding layer.

20. The method of clause 18, further comprising applying a force of less than 15 N, a torque of less than 10 Nm, or gravity to separate the first and second substrates.

[0054] Although specific reference may be made in this text to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein may have other applications. Possible other applications include the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat- panel displays, liquid-crystal displays (LCDs), thin film magnetic heads, etc.

[0055] Although specific reference may be made in this text to embodiments of the disclosure in the context of a lithographic apparatus, embodiments of the disclosure may be used in other apparatuses. Embodiments of the disclosure may form part of a mask inspection apparatus, a metrology apparatus, or any apparatus that measures or processes an object such as a wafer (or other substrate) or mask (or other patterning device). These apparatuses may be generally referred to as lithographic tools. Such lithographic tools may use vacuum conditions or ambient (non vacuum) conditions.

[0056] Although specific reference may have been made above to the use of embodiments of the disclosure in the context of optical lithography, it will be appreciated that the disclosure, where the context allows, is not limited to optical lithography and may be used in other applications, for example imprint lithography.

[0057] It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by those skilled in relevant art(s) in light of the teachings herein.

[0058] The above examples are illustrative, but not limiting, of the embodiments of this disclosure. Other suitable modifications and adaptations of the variety of conditions and parameters normally encountered in the field, and which would be apparent to those skilled in the relevant art(s), are within the spirit and scope of the disclosure.

[0059] While specific embodiments of the disclosure have been described above, it will be appreciated that the disclosure may be practiced otherwise than as described. The descriptions above are intended to be illustrative, not limiting. Thus it will be apparent to one skilled in the art that modifications may be made to the disclosure as described without departing from the scope of the claims set out below.

[0060] It is to be appreciated that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present invention as contemplated by the inventor(s), and thus, are not intended to limit the present invention and the appended claims in any way. [0061] The present invention has been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.

[0062] The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present invention. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein.

[0063] The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.