Metal heater assembly with embedded resistance heater

Abstract

The metallic heater includes a metallic substrate having a groove, a resistive heater disposed within the groove, and a filler metal disposed over the resistive heater and substantially filling the groove, the filler metal having a lower melting temperature than the metallic substrate. The filler metal may be indium, and a cover plate may be bonded to the metallic substrate over the indium. Methods of manufacturing and operating the metallic heater are also provided.

Description

Technical Field

[0005] ,

[0001] (Cross - Reference to Related Applications) This application claims the priority and benefit of U.S. Provisional Patent Application No. 63 / 183,932, filed on May 4, 2021. The disclosure of the above application is hereby incorporated by reference in its entirety into this specification.

[0002] (Field) The present disclosure relates to a metal heater with an embedded heating element.

Background Art

[0003] The description in this section merely provides background information related to the present disclosure and does not constitute prior art.

[0004] Metal heaters are used in various applications to provide heat to a target and / or the environment by resistive heating. One such resistive heater is a cartridge heater, which generally includes a resistive wire heating element wound around a ceramic core. In conventional applications, the ceramic core defines two longitudinal bores in which power pins and terminal pins are disposed. The first end of the resistive wire is electrically connected to one power pin, and the other end of the resistive wire is electrically connected to the other power pin. The ceramic core assembly is disposed within a tubular metal sheath having an open end and a closed end, or in some assemblies two open ends, forming an annular space between the sheath and the resistive wire / core assembly. An insulating material, such as magnesium oxide (MgO), is poured into the open end of the sheath to fill the annular space between the resistive wire and the inner surface of the sheath.

[0005] The open end(s) of the sheath are sealed, for example, with a potting compound and / or separate sealing members. The sheath assembly may then be shrunk or compressed, for example, by crimping or other suitable process, to reduce the diameter of the sheath and shrink and compress the MgO, thereby crushing the ceramic core at least partially, so that the core is crushed against the pins and good electrical contact and heat transfer are ensured. The compressed MgO provides a relatively sufficient heat transfer path between the resistance heating element and the sheath and also electrically insulates the sheath from the resistance heating element. In this way, the heat generated through the resistance heating element is transferred to the body of the metal heater, allowing the entire body of the metal heater to operate at the desired temperature.

[0006] Applications of metal heaters include thin-film processing in semiconductor device manufacturing. For example, thin-film processing such as chemical vapor deposition (CVD), physical vapor deposition (PVD), and atomic layer deposition (ALD) may use metal heaters to heat the substrate during processing. Even very small temperature changes, even fractions of a degree Celsius, can affect the outcome of such film processing. Therefore, in these applications of metal heaters, it is crucial that the temperature is precisely and repeatedly controlled throughout the entire body of the metal heater.

[0007] These issues relating to metal heaters for use in semiconductor device manufacturing are addressed by this disclosure. [Overview of the Initiative]

[0008] This section provides a general overview of this disclosure and does not constitute a comprehensive disclosure of its entire scope or all its features.

[0009] In one embodiment of the present disclosure, the metal heater comprises a metal substrate having grooves formed therein, a resistance heater disposed within the grooves, and a filler metal disposed on the resistance heater and substantially filling the grooves, wherein the filler metal has a lower melting temperature than the metal substrate.

[0010] In this variation of the metal heater, which can be implemented individually or in any combination, the resistance heater is selected from a group consisting of layered heaters, cable heaters, tubular heaters, cartridge heaters, and foil heaters, the resistance heater is a cartridge heater, the resistance heater is a cable heater, the substrate is formed of metal or a metal alloy, the filler metal is indium, the cover plate is fixed to the metal substrate and placed on top of the filler metal, the substrate has multiple grooves, the corresponding multiple resistance heaters are placed in the multiple grooves, the grooves define an arc-shaped internal contour, the multiple resistance heaters are placed in a single groove, at least one spacer is placed between adjacent resistance heaters of the multiple resistance heaters, the amount of filler metal is calculated based on the temperature change in volume of the filler metal, the size of the resistance heaters, and the size of the grooves, at least one additional groove is substantially filled with filler metal, at least one additional groove does not contain a resistance heater, layers of multiple resistance heaters are placed in the corresponding multiple grooves, and the filler metal is placed on top of the multiple resistance heaters and substantially fills the multiple grooves.

[0011] According to another embodiment of the present disclosure, a method for forming a heating element includes forming a groove in a metal substrate, placing a resistance heater in the groove, filling the groove with a molten filler metal having a lower melting point than the metal substrate, cooling the metal substrate and the molten filler metal so that the groove is filled with solidified filler metal and the resistance heater is embedded in the solidified filler metal, and fixing a cover plate to the metal substrate to cover the solidified filler metal.

[0012] In variations of this method, which may be carried out individually or in any combination, the metal substrate is heated before the grooves are filled with molten filler metal, the metal substrate and molten filler metal are cooled to room temperature before the cover plate is joined to the metal substrate, the joining of the cover plate to the metal substrate comprises brazing or welding the cover plate to the metal substrate, and the molten filler metal is indium.

[0013] In yet another embodiment of the present disclosure, a method for operating a heater comprises supplying power to a metal heater, the metal heater comprising a metal substrate having grooves formed therein, a resistance heater disposed within the grooves, and a filler metal disposed above the resistance heater and substantially filling the grooves, the filler metal having a lower melting temperature than the metal substrate. The power supply to the metal heater is increased so that the resistance heater provides enough heat to melt the filler metal, the filler metal changing from a solid state to a liquid state during the operation of the heater while the metal substrate remains solid. In one variation of this method, the filler metal is indium.

[0014] Further areas of application will become apparent from the descriptions provided herein. It should be understood that these descriptions and examples are for illustrative purposes only and are not intended to limit the scope of this disclosure. [Brief explanation of the drawing]

[0015] To ensure that this disclosure can be properly understood, various forms of this disclosure given as examples will be described below with reference to the attached drawings.

[0016] [Figure 1] Figure 1 is a top view of a heater assembly configured according to the teachings of this disclosure.

[0017] [Figure 2] Figure 2 is a cross-sectional view of section 2-2 of Figure 1.

[0018] [Figure 3A] Figure 3A shows the steps for forming the heater assembly shown in Figure 1.

[0019] [Figure 3B] Figure 3B shows another step in forming the heater assembly shown in Figure 1.

[0020] [Figure 3C] Figure 3C shows yet another step in forming the heater assembly shown in Figure 1.

[0021] [Figure 3D] Figure 3D shows yet another step of forming the heater assembly of FIG. 1.

[0022] [Figure 4A] FIG. 4A is a cross-sectional view of a resistive heater disposed in one form of a rectangular groove according to the teachings of the present disclosure.

[0023] [Figure 4B] FIG. 4B is a cross-sectional view of a resistive heater disposed in another form of a rectangular shape. [[ID=​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ [Figure 8] Figure 8 is a flowchart showing a method for manufacturing the heater according to this disclosure.

[0031] [Figure 9] Figure 9 is a cross-sectional view of another embodiment of a heater assembly configured according to the teachings of this disclosure.

[0032] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way. [Modes for carrying out the invention]

[0033] The following descriptions are illustrative in nature and are not intended to limit the disclosure, applications, or use. Throughout the drawings, it should be understood that corresponding reference numbers indicate similar or corresponding parts and features.

[0034] Referring here to Figures 1 and 2, a heater assembly 10 (e.g., a pedestal heater assembly) relating to the teachings of this disclosure is shown. The heater assembly 10 includes a substrate 100 having at least one groove 110 and a cover plate 160 (omitted in Figure 1 for clarity) fixed to the substrate 100 and positioned over the groove 110. In one embodiment, as shown in Figure 1, the groove 110 defines a helical shape as shown. In other embodiments, the groove 110 has different shapes, such as multiple grooves that are linear, meandering, and concentric.

[0035] Referring particularly to Figure 2, the groove 110 extends from the upper (+z direction) surface 102 to the lower (-z direction) surface 104 of the substrate 100, and the resistance heater 150 is positioned within the groove 110. For example, in one embodiment, the resistance heater 150 is positioned at or near the bottom (-z direction) of the groove 110. However, the resistance heater 150 may be positioned anywhere within the groove 110, and may optionally protrude above the groove 110, while remaining within the scope of this disclosure. A low melting temperature metal or alloy 112 (hereinafter simply referred to as “filler metal 112”) is also positioned within the groove 110, and the resistance heater 150 is positioned within or embedded in the filler metal 112. The cover plate 160 extends across the upper surface 102 and the groove 110, as shown. In some modifications, the cover plate 160 is fixed to the substrate 100 (e.g., by welding or brazing). However, it should be understood that the cover plate 160 is optional.

[0036] With respect to the filler metal 112, metals and metal alloys typically melt over a temperature range. Therefore, as used herein, the term "melting temperature" refers to the temperature range from the temperature at which the filler metal 112 begins to change from solid to liquid to the temperature at which the metal completely liquefies / melts. Thus, the melting temperature may be a temperature range with respect to the filler metal 112 and is not necessarily limited to a single specific temperature.

[0037] Non-limiting examples of materials from which the substrate 100 and / or cover plate 160 are made include steel, stainless steel, and aluminum alloys. Non-limiting examples of the resistance heater 150 include cable heaters, cartridge heaters, bare wire heating elements, coil heaters, tubular heaters, layered heaters, and foil heaters. Furthermore, it should be understood that the teachings of this disclosure include not only a single resistance heater 150 but also multiple resistance heaters 150 that are arranged within a zone and can be controlled independently. Also, multiple types of resistance heaters 150 may be used in the heater assembly 10 while remaining within the scope of this disclosure.

[0038] Referring here to Figures 3A-3D, a method 20 for forming the heater assembly 10 is shown. Method 20 includes arranging a resistance heater 150 in a groove 110, as shown in Figure 3A. The groove 110 may be formed by methods known in the art, such as cutting with a grooving knife, drilling, grinding, milling, turning, etc. As shown in the figure, the size (e.g., diameter) of the groove 110 is larger than (exceeds) the diameter or outer dimension of the resistance heater 150. In one embodiment of the present disclosure, the size of the groove 110 is at least 100% larger than the diameter of the resistance heater 150. In at least one embodiment, the size of the groove 110 is at least 200% larger than the diameter of the resistance heater 150, for example, about 300%, about 400%, about 500%, about 600%, about 700%, or about 1000% larger than the diameter of the resistance heater 150.

[0039] Referring to Figure 3B, Method 20 includes pouring the liquid-filled metal 112a into the groove 110 such that the upper surface 113 of the liquid-filled metal 112a is at a desired height (in the z direction), as shown in Figure 3C. Method 20 also includes fixing the cover plate 160 to the substrate 100, as shown in Figure 3D. In one embodiment, the substrate 100, with a resistance heater 150 placed in the groove 110, is heated before the liquid-filled metal 112a is poured into the groove 110. In at least one modification, the substrate 100, with a resistance heater 150 placed in the groove 110, is heated to a temperature approximately equal to or higher than the melting temperature of the liquid-filled metal 112a. For example, in one variation, the liquid-filled metal 112a is liquid indium (T(melt) ≈ 157°C), and the substrate 100, in which a resistance heater 150 is placed in the groove 110, is heated to above 157°C (i.e., overheated) before the liquid indium is poured into the groove 110. As a result of heating the substrate 100, the volume of the substrate 100 expands, and the volume (and size) of the groove 110 increases. Thus, when the groove 110 filled with the liquid-filled metal 112a cools, the solidification shrinkage of the liquid-filled metal 112a is at least partially absorbed by the volume contraction of the substrate 100.

[0040] In one embodiment, the groove 110 is filled with liquid-filled metal 112a such that the upper surface 113 of the liquid-filled metal 112a is at approximately the same height (z-direction) or on the same plane (xy-plane) as the upper surface 102 of the substrate 100. The liquid-filled metal 112a also solidifies so that the resistance heater 150 is embedded within the filling metal 112. The resistance heater 150 may be completely surrounded or embedded by the filling metal 112, or partially surrounded or embedded by the filling metal 112.

[0041] It should be understood that the filler metal 112 functions as an improved heat transfer medium compared to physical contact between the resistive heater 150 and the substrate 100. For example, a heater assembly having heating elements arranged in grooves of roughly the same size may result in gaps / air gaps (e.g., air gaps) between the heating elements and the substrate along the length of the heating elements. Such gaps reduce heat transfer between the heating elements and the substrate, leading to undesirable, uneven heating of the substrate. In contrast, by pouring liquid filler metal 112a into the grooves 110 and over the resistive heater 150, direct and close contact is established between the resistive heater 150 and the filler metal 112, and between the filler metal 112 and the substrate 100. That is, the filler metal 112 improves metal-to-metal contact without the presence of gaps between the resistive heater 150 and the substrate 100. Thus, the heater assembly 10 according to the teachings of this disclosure, which will be further described below, provides improved heat transfer and improved heat transfer uniformity.

[0042] Non-limiting examples of the filler metal 112 include indium (T(melt) ≈ 157°C), tin (T(melt) ≈ 232°C), zinc (T(melt) ≈ 420°C), and their alloys. It should be understood that the liquid filler metal 112a typically exhibits a decrease in volume (shrinkage) during solidification. For example, indium exhibits a solidification shrinkage of approximately 4 volume%. It should also be understood that such solidification shrinkage is taken into account when pouring the liquid filler metal 112a into the groove so that the top surface 113 of the filler metal 112 is at a desired height (z-direction) relative to the top surface 102 of the substrate 100. In some modifications, the solidification shrinkage of the liquid filler metal 112a is taken into account so that the top surface 113 is substantially planar with the top surface 102 of the substrate 100. In other modifications, the solidification shrinkage of the liquid filler metal 112a is considered such that the upper surface 113 of the filler metal 112 is a predetermined distance below (in the -z direction) the upper surface 102 of the substrate 100. Also in at least one modification, the solidification shrinkage of the liquid filler metal 112a is considered such that the upper surface 113 of the filler metal 112 is a predetermined distance above (in the +z direction) the upper surface 102 of the substrate 100. In such a modification, the upper surface 113 may be lowered (in the -z direction) by grinding so that a plane is obtained between the upper surface 102 of the substrate and the filler metal 112.

[0043] Figures 2 and 3A–3D show grooves 110 having an arc-shaped internal contour (e.g., a circular or semicircular internal contour), but heater assemblies having grooves with other shapes of internal contours are included in the teachings of this disclosure. For example, Figures 4A–4B show an example of a rectangular groove 110 with a resistance heater 150 located at the bottom and a filler metal 112 disposed inside.

[0044] Referring to Figures 5A to 5B, a resistance heater 150 is located at the bottom, and an angled groove 110 with a filling metal 112 inside is shown.

[0045] Referring to Figure 6, a trapezoidal groove 110 is shown with a resistance heater 150 located at the bottom and a filling metal 112 placed inside.

[0046] Referring to Figures 7A-7C, an oval-shaped groove 110 is shown. In Figure 7A, the resistance heater 150 is located at the bottom of the oval-shaped groove 110, and the filler metal 112 is placed within the oval-shaped groove 110. In Figures 7B and 7C, a pair of resistance heaters 150 is located at the bottom of the oval-shaped groove 110, and the liquid filler metal 112a is poured into the oval-shaped groove to form the filler metal 112. In the modified example shown in Figure 7C, a spacer or insert 115 is placed between the pair of resistance heaters 150 within the oval-shaped groove 110, and the liquid filler metal 112a is poured into two separate cavities between the insert 115 and the inner surface of the groove 110. Thus, according to the teachings of this disclosure, multiple resistance heaters 150 can be placed within a single groove 110 with or without spacers. Furthermore, the resistance heater 150 does not need to be located at the bottom of the groove 110 as shown herein, and can be held in place at any position within the groove 110 while the liquid-filled metal 112a is poured into the groove(s) 110.

[0047] Referring to Figure 8, method 40 for forming a heater (e.g., heater assembly 10) includes forming a groove (e.g., groove 110) in a metal substrate (e.g., substrate 100) in 410, and placing a resistance heater (e.g., resistance heater 150) in the groove in 420. In 430, the metal substrate is heated to about 157°C or higher, for example, if the filler metal is indium, and in 440, the groove is filled with molten filler metal. In 450, the metal substrate and molten filler metal are cooled to room temperature to allow the molten filler metal to solidify. A cover plate may then be fixed to the metal substrate (not shown). Alternatively, filler metal may be used to fill an existing groove without a cover plate. In this case, the groove is located in or embedded in the metal substrate, and the end(s) of the groove are sealed after filling the groove. These and other variations should be construed as falling within the scope of this disclosure.

[0048] According to another embodiment of this disclosure, a method for operating the heater assembly 10 (also referred to herein as the “metal heater”) includes supplying power to the metal heater 10 and increasing the power so that the resistance heater 150 supplies enough heat to melt the filler metal 112, which changes from a solid state to a liquid state during the operation of the heater 10 while the metal substrate 100 remains solid. Thus, during the operation of the heater assembly 10, the filler metal 112 melts to fill any voids, expanding in volume and increasing heat transfer from the resistance heater 150 to the metal substrate 100.

[0049] It should be understood that the filler metal 112 does not need to completely fill the groove 110 while remaining within the scope of this disclosure. Based on the material properties of the filler metal 112, the temperature-dependent volume change can be calculated so that the volume during operation is sufficient to completely enclose the resistance heater 150 or to enclose it to a degree sufficient to improve heat transfer. In this approach, the temperature-dependent volume change of the filler material 112, the size of the resistance heater 150, and the size of the groove 110 are considered in order to calculate the amount of filler metal 112 needed to adequately enclose the resistance heater 150 during operation. Alternatively, if the volume of the filler metal 112 is fixed, the size of the groove 110 to adequately enclose the resistance heater 150 can be calculated.

[0050] Referring here to Figure 9, another embodiment of the metal heater is shown, generally designated by reference numeral 200. In this embodiment, multiple “layered” embedded resistance heaters 210 are arranged in grooves 220 of a metal substrate 230 (or multiple individual substrates bonded to each other, not shown). The metal heaters 200 also include a filler metal 240, as described above, which has a lower melting temperature than the metal substrate 230. In this embodiment, the layers of resistance heaters 210 are arranged in an alternating configuration along the X-axis and layered along the Z-axis, as shown, to provide improved temperature uniformity. This arrangement of resistance heaters 210 and grooves 220 is merely illustrative, and it should be understood that any number of layers and positions of resistance heaters 210 and grooves 220 can be implemented while remaining within the scope of this disclosure. Furthermore, the metal heaters 200 may generally include any of the features described above individually or in any combination, while remaining within the scope of this disclosure. For example, in this configuration, cover plates 250 are provided on both the top and bottom of the metal heater 200.

[0051] Unless otherwise explicitly stated herein, all numerical values ​​indicating mechanical / thermal properties, compositional ratios, dimensions and / or tolerances, or other characteristics should be understood to be modified with the word "approximately" or "approximately" in order to describe the scope of this disclosure. This modification is desired for a variety of reasons, including industrial practice, material, manufacturing and assembly tolerances, and test performance.

[0052] Terms such as "first," "second," and "third" may be used to describe various elements, components, regions, layers, and / or parts, but these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, and / or part from another element, component, region, layer, and / or part. Terms such as "first," "second," and other numerical terms, when used herein, do not imply order or hierarchy unless explicitly stated by context. Thus, a first element, component, region, layer, or part may be referred to as a second element, component, region, layer, or part without deviating from the teaching of the exemplary form. Furthermore, an element, component, region, layer, or part may be referred to as a "second" element, component, region, layer, or part without requiring an element, component, region, layer, or part referred to as a "first" element, component, region, layer, or part.

[0053] For example, spatially relative terms such as “inside,” “outside,” “down,” “below,” “underside,” “up,” and “top” may be used herein to facilitate descriptions of the relationship between one element or feature and another element or feature(s) as shown in the figures. Spatially relative terms may be intended to encompass different orientations of a device in use or operation, in addition to the orientation shown in the figures. For example, if the device in the figure is inverted, an element described as “below” or “underside” another element or feature will be oriented “above” the other element or feature. Thus, the exemplary term “down” may encompass both up and down orientations. The device may have other orientations (a 90-degree rotation or other orientations), and the spatially relative descriptive terms used herein will be interpreted accordingly.

[0054] As used herein, the expression "at least one of A, B, and C" should be interpreted as meaning a logical (A or B or C) using non-exclusive OR, and not as meaning "at least one of A, at least one of B, and at least one of C."

[0055] The terms used herein are intended solely to describe specific exemplary forms and are not intended to be restrictive. The singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context explicitly indicates otherwise. The terms “includes” and “have” are inclusive and thus indicate the presence of the described features, integers, steps, actions, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, actions, elements, components, and / or groups thereof. The steps, processes, and actions of the methods described herein are not necessarily construed to require execution in a specific order described or illustrated unless specifically identified as the order of execution. It should also be understood that additional or alternative steps may be used.

[0056] Since the descriptions in this disclosure are essentially illustrative, any modifications that do not deviate from the essence of this disclosure are intended to be within the scope of this disclosure. Such modifications shall not be deemed to deviate from the intent and scope of this disclosure. The invention described in the original claims of this application is listed below. [1] A metal substrate with grooves formed on it, A resistance heater is disposed within the groove, A filling metal disposed on the resistance heater and substantially filling the groove, the filling metal having a lower melting temperature than the metal substrate. A metal heater equipped with a heater. [2] The resistance heater is selected from the group consisting of layered heaters, cable heaters, tubular heaters, cartridge heaters, and foil heaters, and is a metal heater as described in [1]. [3] The aforementioned resistance heater is a cartridge heater, as described in [1]. [4] The aforementioned resistance heater is a cable heater, as described in [1]. [5] The metal heater according to [1], wherein the metal substrate is formed of a metal or a metal alloy. [6] The metal heater according to [1], wherein the filling metal is indium. [7] The metal heater according to [6], further comprising a cover plate fixed to the metal substrate and positioned on the filling metal. [8] The metal heater according to [1], further comprising a plurality of grooves and a plurality of corresponding resistance heaters disposed within the plurality of grooves. [9] The groove defines the internal contour of the metal heater according to [1].

[10] The metal heater according to [1], further comprising a plurality of resistance heaters arranged in a single groove.

[11] The metal heater according to

[10] further comprises at least one spacer positioned between adjacent resistance heaters of the plurality of resistance heaters.

[12] The amount of the filling metal is calculated based on the volume change of the filling metal with temperature, the size of the resistance heater, and the size of the groove, as described in [1].

[13] The metal heater according to [1], further comprising at least one additional groove substantially filled with the filling metal, wherein the at least one additional groove does not include a resistance heater.

[14] The metal heater according to [1], further comprising layers of multiple resistance heaters arranged in a plurality of corresponding grooves, wherein the filling metal is placed on the plurality of resistance heaters and substantially fills the plurality of grooves.

[15] A method for forming a heating element, Forming grooves in a metal substrate, The resistive heater is placed in the groove, The groove is filled with a molten filler metal having a lower melting temperature than the metal substrate, The metal substrate and the molten filling metal are cooled so that the groove is filled with solidified filling metal and the resistance heater is embedded in the solidified filling metal. The solidified filling metal is covered and the cover plate is fixed to the metal substrate. A method for providing this.

[16] The method according to

[15] , further comprising heating the metal substrate before filling the groove with molten filler metal.

[17] The method according to

[15] , wherein the metal substrate and the molten filler metal are cooled to room temperature before the cover plate is bonded to the metal substrate, covering the solidified filler metal.

[18] The method according to

[15] , wherein joining the cover plate to the metal substrate is performed by brazing or welding the cover plate to the metal substrate.

[19] The method according to

[15] , wherein the molten-filled metal is indium.

[20] A method for operating a heater, The process involves supplying power to a metal heater, wherein the metal heater is A metal substrate with grooves formed on it, A resistance heater is disposed within the groove, A filling metal disposed on the resistance heater and substantially filling the groove, the filling metal having a lower melting temperature than the metal substrate. To be equipped with, The power is increased so that the resistance heater supplies enough heat to melt the filling metal, and the filling metal changes from a solid state to a liquid state during the operation of the heater while the metal substrate remains solid. A method for providing this.

[21] The method according to

[20] , wherein the filling metal is indium.

Claims

1. A metal substrate with grooves formed on it, A resistance heater is disposed within the groove, A filling metal disposed on the resistance heater and substantially filling the groove, the filling metal having a lower melting temperature than the metal substrate. Equipped with, The filling metal is a metal heater that changes from a solid state to a liquid state during the operation of the resistance heater while the metal substrate remains in a solid state.

2. The metal heater according to claim 1, wherein the resistance heater is selected from the group consisting of layered heaters, cable heaters, tubular heaters, cartridge heaters, and foil heaters.

3. The metal heater according to claim 1, wherein the resistance heater is a cartridge heater.

4. The metal heater according to claim 1, wherein the resistance heater is a cable heater.

5. The metal heater according to claim 1, wherein the metal substrate is formed of a metal or a metal alloy.

6. The metal heater according to claim 1, wherein the filling metal is indium.

7. The metal heater according to claim 6, further comprising a cover plate fixed to the metal substrate and disposed on the filling metal.

8. The metal heater according to claim 1, further comprising a plurality of grooves and a plurality of corresponding resistance heaters disposed within the plurality of grooves.

9. The metal heater according to claim 1, wherein the groove defines an arc-shaped internal contour.

10. The metal heater according to claim 1, further comprising a plurality of resistance heaters arranged in a single groove.

11. The metal heater according to claim 10, further comprising at least one spacer disposed between adjacent resistance heaters of the plurality of resistance heaters.

12. The metal heater according to claim 1, further comprising at least one additional groove substantially filled with the filling metal, wherein the at least one additional groove does not include a resistance heater.

13. The metal heater according to claim 1, further comprising layers of multiple resistance heaters arranged in a plurality of corresponding grooves, wherein the filling metal is placed on the plurality of resistance heaters and substantially fills the plurality of grooves.

14. A method for forming a heating element, Forming grooves in a metal substrate, The resistive heater is placed in the groove, While the metal substrate remains solid, a molten filler metal having a lower melting point than the metal substrate changes from a solid state to a liquid state due to the lower melting point during the operation of the resistance heater, and the groove is filled with the molten filler metal. The metal substrate and the molten filling metal are cooled so that the groove is filled with solidified filling metal and the resistance heater is embedded in the solidified filling metal. The solidified filling metal is covered and the cover plate is fixed to the metal substrate. A method for providing this.

15. The method according to claim 14, further comprising heating the metal substrate before filling the groove with molten filler metal.

16. The method according to claim 14, wherein the metal substrate and the molten filler metal are cooled to room temperature before the cover plate is joined to the metal substrate, covering the solidified filler metal.

17. The method according to claim 14, wherein joining the cover plate to the metal substrate comprises brazing or welding the cover plate to the metal substrate.

18. The method according to claim 14, wherein the molten filling metal is indium.

19. A method for operating a heater, The process involves supplying power to a metal heater, wherein the metal heater is A metal substrate with grooves formed on it, A resistance heater is disposed within the groove, A filling metal disposed on the resistance heater and substantially filling the groove, the filling metal having a lower melting temperature than the metal substrate. To be equipped with, The power is increased so that the resistance heater supplies enough heat to melt the filling metal, and the filling metal changes from a solid state to a liquid state during the operation of the heater while the metal substrate remains solid. A method for providing this.

20. The method according to claim 19, wherein the filling metal is indium.

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