Metal-embedded silica material and method for manufacturing the same

Abstract

The present invention provides a metal-encapsulated silica material and a method for manufacturing the same, which maintains better adhesion between silica materials than conventional materials, suppresses degradation of the metal component of the conductor, exhibits good conductive properties, and has a long lifespan. [Solution] The metal-embedded silica material comprises a first silica material 1, a second silica material 2 whose surface is aligned opposite to the first silica material, a conductor 3 disposed between the first silica material and the second silica material, and a joint 4 in which at least the peripheral edge of the mating surface between the first silica material and the second silica material is joined in a continuous ring shape along the periphery, wherein the OH group content of the first silica material and the second silica material is 1000 ppm or less, the conductor is a thin film, foil, wire, plate or strip, and the conductor is made of one selected from the group consisting of Ir, Pt, Rh, Ru, Re and Mo, or an alloy containing at least one selected from that group.

Description

Technical Field

[0001] The present disclosure relates to, for example, a metal-encapsulated silica material that can be used as a heater for heating, for example, wafers, substrates, etc. or various sensors in the field of semiconductors and electronic components, and a method for manufacturing the same.

Background Art

[0002] There is a disclosure of a quartz heater 31 having a heating surface made of a resistive heating element, for example, 5 to 10 microns thick, which is formed by screen-printing a mixture of platinum (Pt) and oxides (such as SiO and PbO) with an organic substance added to make a paste on a quartz plate having a hole for passing a quartz tube therethrough and a hole for passing a quartz rod therethrough, and then baking and solidifying it (for example, see Patent Document 1). In this example, an opening is formed in the central portion of the quartz plate, and a quartz tube extending vertically to the lower end of the heat insulating substrate is joined to this opening. A power supply line is connected to the heating surface, and this power supply line is inserted into the quartz tube. A quartz plate having a slightly protruding peripheral portion is stacked on the quartz plate, and the peripheral portions of both quartz plates are joined to each other, for example, by welding. A recess is formed in the center of the inner surface of the upper quartz plate, and the tip of a thermocouple, which is a temperature detection part inserted into the quartz tube, is accommodated in the recess. The power supply line and the thermocouple extend through the quartz tube to the lower end. Also, a reflector 41 having a reflecting surface, which is disposed under the quartz heater 31, is made in the same manner as the quartz heater 31 except that a power supply line is not connected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, a quartz heater 31 positioned at the top of the heat insulating substrate is used as both a heater and a temperature sensor, and a reflector 41 positioned below the quartz heater 31 is used as a reflector. The two quartz plates sandwiching the heating surface of the quartz heater or the reflective surface of the reflector are joined at their peripheral edges, for example, by welding. However, because the quartz heater is used at high temperatures, the joint is prone to deterioration, and deterioration of the internal heating surface is also likely to occur.

[0005] The present disclosure aims to provide a metal-encapsulated silica material and a method for manufacturing the same, which can withstand use up to 1000°C, maintains better adhesion between silica materials than conventional materials, suppresses degradation of the metal component of the conductor, has good conductive properties, and has a long lifespan. [Means for solving the problem]

[0006] The present inventors, after diligent study, have found that the above problems can be solved by adjusting the OH group content of the silica material to a predetermined range, and have completed the present invention. That is, the metal-encapsulated silica material according to the present invention is a metal-encapsulated silica material comprising: a first silica material; a second silica material whose surface is aligned opposite to the first silica material; a conductor disposed between the first silica material and the second silica material; and a joint portion in which at least the peripheral portion of the mating surface between the first silica material and the second silica material is joined in a ring-like manner along the periphery, wherein the OH group content of the first silica material and the second silica material is 1000 ppm or less, the conductor is a thin film, foil, wire, plate, or strip, and the conductor is made of one selected from the group consisting of Ir, Pt, Rh, Ru, Re, and Mo, or an alloy containing at least one selected from the group consisting of Ir, Pt, Rh, Ru, Re, and Mo, and having a melting point of 1200°C or higher.

[0007] The metal-encapsulated silica material according to the present invention is included in the context of being a heater or a sensor.

[0008] In the metal-encapsulated silica material according to the present invention, it is preferable that the first silica material and the second silica material have a content of 1 ppm or less of each element Li, Na, K, Ca, Mg, B, Fe, and Cu, and an Al content of 10 ppm or less. This can suppress contamination in the usage environment, such as in a heat treatment furnace.

[0009] In the metal-encapsulated silica material according to the present invention, it is preferable that the surface roughness of at least a portion of the outer peripheral plane of the first silica material and the second silica material has an arithmetic mean roughness Ra of 5 μm or less. This can improve heat uniformity.

[0010] In the metal-encapsulated silica material according to the present invention, it is preferable that at least one of the first silica material and the second silica material has a cavity on its opposing surface, and that the conductor is housed in the cavity. By housing the conductor in the cavity, the stress on the joint between the silica materials can be reduced.

[0011] In the metal-encapsulated silica material according to the present invention, it is preferable that at least one of the first silica material and the second silica material has a recess on its outer peripheral plane for holding the object to be processed. When the metal-encapsulated silica material is, for example, a susceptor, it is possible to facilitate the accommodation of the substrate to be heated.

[0012] In the metal-encapsulated silica material according to the present invention, the thickness of the first silica material and the second silica material is preferably 0.5 to 10 mm. This suppresses energy loss due to heat absorption by the metal-encapsulated silica material itself and improves the thermal responsiveness of the furnace body during heating and cooling.

[0013] In the metal-encapsulated silica material according to the present invention, it is preferable that the thickness of the thin film is 1 μm or less, the thickness of the foil is less than 100 μm, the diameter of the wire is 0.1 to 3 mm, the thickness of the plate is 5 mm or less, and the thickness of the strip is 5 mm or less. This ensures the conductivity of the conductor while suppressing energy loss due to heat absorption by the conductor itself, thereby improving the thermal responsiveness of the furnace body during heating and cooling.

[0014] In the metal-encapsulated silica material according to the present invention, the conductor is a thin film, and the metal-encapsulated silica material preferably has an oxide layer containing one selected from the group of oxides consisting of silicon oxide, aluminum oxide, lithium tantalate, lithium niobate, magnesium oxide, titanium oxide, yttrium oxide, strontium titanate, germanium oxide, zinc oxide, indium oxide, indium tin oxide, tin oxide, tungsten-doped tin oxide, and tantalum oxide, or an oxide layer containing two or more selected from the group of oxides, at least one location between the first silica material and the conductor, and between the second silica material and the conductor, and the thickness of the oxide layer is 50 nm or less. The oxide layer promotes adhesion between the thin film which is the conductor and the silica material, and can suppress heat absorption by the oxide layer.

[0015] The present invention provides a method for manufacturing a metal-encapsulated silica material, comprising: a first step of preparing a first silica material and a second silica material; a second step of preparing a foil, wire, plate, or strip as the conductor, or forming a thin film as the conductor on at least one of the surfaces of the first silica material and the second silica material; a third step of aligning the surfaces of the first silica material and the second silica material and arranging the conductor between the first silica material and the second silica material; and a fourth step of joining at least the peripheral edges of the opposing surfaces of the first silica material and the second silica material.

[0016] In the method for manufacturing metal-encapsulated silica material according to the present invention, it is preferable to perform a fifth step after the fourth step, in which the outer surface of the first silica material and the second silica material is polished to adjust the final plate thickness. This allows for more precise adjustment of the final plate thickness.

[0017] In the method for manufacturing metal-encapsulated silica material according to the present invention, it is preferable that in the fourth step, the first silica material and the second silica material are joined at a pressure of 10 MPa or less and a temperature of 400 to 1000°C after creating an atmosphere of either a vacuum atmosphere of 100 Pa or less, an argon atmosphere, or a nitrogen atmosphere. This allows for reliable joining of the silica materials while suppressing deterioration of the conductor due to oxygen, hydrogen, or heat.

[0018] In the method for manufacturing a metal-encapsulated silica material according to the present invention, it is preferable to further include step A between the third step and the fourth step, in which a spacer made of carbon, oxide, nitride, or boride, or a spacer containing at least one selected from the group consisting of carbon, oxide, nitride, and boride, is placed at a location that contacts at least the outer surface of the first silica material and the second silica material. The first silica material and the second silica material can be joined while suppressing contamination of the conductor by impurities.

[0019] In the method for manufacturing a metal-encapsulated silica material according to the present invention, a step B is further included between the third step and the fourth step, in which a plurality of stacked bodies are prepared, each consisting of a first silica material and a second silica material obtained in the third step and a spacer placed at a location that contacts at least the outer surface of the first silica material and the second silica material, and 2 to 30 sets of these stacked bodies are stacked in the stacking direction to form a stacked body, wherein the spacer is made of carbon, oxide, nitride or boride, or includes at least one selected from the group consisting of carbon, oxide, nitride and boride, and the fourth step is preferably a step in which 2 to 30 sets of the stacked first silica material and second silica material are joined simultaneously. Multiple sets of the first silica material and second silica material can be joined simultaneously while suppressing the joining of different silica materials, such as the first silica material and another second silica material, or another first silica material and a second silica material.

[0020] In the method for producing metal-encapsulated silica material according to the present invention, the material of the spacer is carbon, wherein the sodium and potassium content is 3 ppm or less each, the iron and boron content is 1 ppm or less each, and the copper content is 0.1 ppm or less. Furthermore, it is preferable that the spacer is a spacer containing glassy carbon, a spacer made of glassy carbon, a spacer with glassy carbon coated on part or all of its surface, or a spacer with pyrolysis carbon coated on part or all of its surface. Carbon has self-lubricating properties, so even if it comes into contact with the silica material during bonding, it is unlikely to cause damage, but it has the drawback of easily generating particles. Therefore, by using a spacer such as glassy carbon, particle generation can be reduced.

[0021] In the method for producing a metal-encapsulated silica material according to the present invention, it is preferable that the thin film be formed in the second step by sputtering, chemical vapor deposition, or evaporation. This allows for a uniform thickness of the conductive thin film, thereby ensuring uniform conductivity. Furthermore, it is possible to improve the density of the film, thereby improving its conductivity.

[0022] In the method for manufacturing a metal-encapsulated silica material according to the present invention, it is preferable to further include a step C between the first and second steps, in which the surfaces of the first silica material and the second silica material that are to be placed facing each other in the third step are reverse sputtered. By removing impurities from the opposing surfaces of the first silica material and the second silica material that face each other, the adhesion of the joint between the first silica material and the second silica material can be improved. Furthermore, by removing impurities, it is possible to suppress the deterioration of the conductor 3 caused by the impurities on the surfaces of the first silica material 1 and the second silica material 2 coming into contact and reacting with the surface of the conductor 3. In addition, when the conductor is a film, the adhesion between the first silica material and the conductor, the first silica material and the oxide layer, the second silica material and the conductor, and the second silica material and the oxide layer is improved.

[0023] In the method for manufacturing a metal-encapsulated silica material according to the present invention, it is preferable to further include at least one step selected from the group consisting of a step D of performing heat treatment at 1000°C or lower after the second step and a step E of performing heat treatment at 1200°C or lower after the fourth step. The density of the conductor can be improved and the conductivity can be improved.

Advantages of the Invention

[0024] According to the present disclosure, it is possible to provide a metal-encapsulated silica material that can withstand use up to 1000°C, has better adhesion between silica materials than conventional ones, suppresses deterioration of the metal components of the conductor, has good characteristics based on the conductor, and has a long lifespan, and a method for manufacturing the same.

Brief Description of the Drawings

[0025] [Figure 1] It is a schematic plan view showing a metal-encapsulated silica material according to the present embodiment. [Figure 2] It is a schematic view showing a first example of the A-A cross section of the metal-encapsulated silica material shown in FIG. 1. [Figure 3] It is a schematic view showing a second example of the A-A cross section of the metal-encapsulated silica material shown in FIG. 1. [Figure 4] It is a schematic view showing a third example of the A-A cross section of the metal-encapsulated silica material shown in FIG. 1. [Figure 5] It is a schematic view showing a fourth example of the A-A cross section of the metal-encapsulated silica material shown in FIG. 1. [Figure 6] It is a schematic view showing a fifth example of the A-A cross section of the metal-encapsulated silica material shown in FIG. 1, and is a schematic view of a metal-encapsulated silica material having an oxide layer between the silica material and the conductor. ​​​​​​ [Figure 9] This is a schematic diagram showing an example in which conductive components are attached to a metal-encapsulated silica material according to this embodiment. [Figure 10] Figure 4 is a schematic diagram showing a third example of a method for manufacturing a metal-encapsulated silica material, where (a) is the first step of preparing the first silica material and the second silica material, (b) is the second step of placing a conductor on the surface of the first silica material, (c) is the third step of joining the first silica material and the second silica material with the surfaces of the conductors placed on the first silica material facing each other, and (d) is the fourth step of joining at least the peripheral edges of the opposing surfaces of the first silica material and the second silica material. [Figure 11] Figure 5 is a schematic diagram showing the manufacturing method of the fourth example of a metal-encapsulated silica material, where (e) is the first step of preparing the first silica material and the second silica material, (f) is the second step of placing conductors on both the surface of the first silica material and the surface of the second silica material, (g) is the third step of joining the first silica material and the second silica material by facing the surface of the conductor placed on the first silica material and the surface of the conductor placed on the second silica material, and (h) is the fourth step of joining at least the peripheral edges of the opposing surfaces of the first silica material and the second silica material. [Figure 12] Figure 10 shows a schematic diagram illustrating another example of a process that follows the first step (a), the second step (b), and the third step (c). (c-1) is a step B in which multiple superimposed bodies are prepared, each consisting of a first silica material and a second silica material obtained in the third step, and a spacer placed at a location that contacts at least the outer surface of the first and second silica materials. These superimposed bodies are then stacked 2 to 30 times in the stacking direction with the spacer in between. (d-1) is a fourth step in which the 2 to 30 stacked first and second silica materials are joined together simultaneously. [Figure 13]Figure 11 shows a schematic diagram illustrating another example of a process that follows the first step (e), the second step (f), and the third step (g). Step B involves preparing multiple superimposed bodies, each consisting of a first silica material and a second silica material obtained in the third step, and a spacer placed in contact with at least the outer surface of the first and second silica materials. These superimposed bodies are then stacked 2 to 30 times in the stacking direction, with the spacers in between. Step H-1 is the fourth step, in which the 2 to 30 stacked first and second silica materials are joined together simultaneously. [Modes for carrying out the invention]

[0026] The present invention will be described in detail below with reference to embodiments, but the present invention is not limited to these descriptions. The embodiments may be modified in various ways as long as they achieve the effects of the present invention.

[0027] The metal-encapsulated silica materials according to this embodiment will be described with reference to Figures 1 to 7. The metal-encapsulated silica materials 50, 60, 100, 200, 300, and 400 according to this embodiment are metal-encapsulated silica materials comprising: a first silica material 1; a second silica material 2 whose surface is aligned opposite to the first silica material 1; a conductor 3 disposed between the first silica material 1 and the second silica material 2; and a joint 4 in which at least the peripheral edge of the mating surface between the first silica material 1 and the second silica material 2 is joined in a ring-like manner along the periphery, wherein the OH group content of the first silica material 1 and the second silica material 2 is 1000 ppm or less, the conductor 3 is a thin film, foil, wire, plate, or strip, and the conductor 3 is made of one selected from the group consisting of Ir, Pt, Rh, Ru, Re, and Mo, or an alloy containing at least one selected from the group consisting of Ir, Pt, Rh, Ru, Re, and Mo, and having a melting point of 1200°C or higher.

[0028] (Metal-encapsulated silica material with an internal cavity) In the metal-encapsulated silica materials 50 and 60, a cavity 12 is provided between the opposing surfaces of the first silica material 1 and the second silica material 2, and is sealed on at least one side of the first silica material 1 side and the second silica material 2 side by a joint 4 between their peripheral edges, with a conductor 3 placed inside the cavity 12. The cavity 12 can be provided on the first silica material 1 side, on both the first silica material 1 side and the second silica material 2 side, or on the second silica material 2 side. Figure 2 shows the cavity 12 provided on the first silica material 1 side. In this configuration, a recess is provided on one surface of the first silica material 1, and the second silica material 2 is a flat plate without a recess. By forming a composite plate structure of the first silica material 1 and the second silica material 2, the cavity 12 is provided on the first silica material 1 side. Since the conductor 3 is located within the sealed cavity 12, the joint between the peripheral edges is less susceptible to peeling stress caused by the conductor 3, thus suppressing contamination due to damage to the silica material or the joint. Furthermore, damage due to the difference in thermal expansion between the silica material and the conductor 3 can be avoided.

[0029] Figure 3 shows a configuration in which the cavity 12 is provided on both the first silica material 1 side and the second silica material 2 side. In this configuration, a recess is provided on one surface of the first silica material 1 and a recess is provided on one surface of the second silica material 2, and the structure of the first silica material 1 and the second silica material 2 is formed by joining the recesses together. As a result, the cavity 12 is provided on both the first silica material 1 side and the second silica material 2 side of the opposing surfaces of the first silica material 1 and the second silica material 2.

[0030] In Figures 2 and 3, the conductor 3 is preferably a thick material such as a foil, wire, plate, or strip, but it may also be a thin film. When a thin film is placed as the conductor 3 inside the cavity 12, it is preferable to form the thin film on the bottom surface of the recess of the cavity 12.

[0031] The height of the cavity 12 (vertical length in Figure 2) is preferably 0.1 μm to 5 mm, and more preferably 0.1 μm to 1 mm. The cavity 12 can be configured in three ways: with a recess only on the first silica material 1 side, with recesses on both the first silica material 1 side and the second silica material 2 side, or with a recess only on the second silica material 2 side. In any configuration, the recess forms a ridge on the periphery of the first silica material 1 and / or the periphery of the second silica material 2. In the configuration of Figure 2, the top surface of the ridge formed on the first silica material 1 is joined to the flat portion of the second silica material 2 which is positioned opposite, forming a joint 4 between the periphery portions. In the configuration of Figure 3, the top surfaces of the ridges of the first silica material 1 and the second silica material 2 are joined together, forming a joint 4 between the periphery portions. The recess can be formed by methods such as etching, cutting, or laser processing.

[0032] (Metal-encapsulated silica material without internal cavities) In metal-encapsulated silica materials 100, 200, 300, and 400, the first silica material 1 and the second silica material 2 are joined together with the planes of the first silica material 1 and the plane of the second silica material 2 facing each other, and a conductor 3 sandwiched between them. In other words, the metal-encapsulated silica material has no internal cavity. In Figures 4 to 7, the conductor 3 is preferably a thin film.

[0033] When the conductor 3 is a thin film, there are two forms: one formed on either the first silica material 1 or the second silica material 2, as shown in Figures 1 and 4, and another formed on both the first silica material 1 and the second silica material 2, as shown in Figures 1 and 5. When silica material with a thin film applied and silica material without a thin film applied are combined, voids tend to occur, so it is preferable to apply a thin film to both silica materials and then join them together. In the metal-encapsulated silica material 200, the first silica material 1 is provided with a first conductor 3a (hereinafter sometimes simply referred to as "conductor 3"), and the second silica material 2 is provided with a second conductor 3b (hereinafter sometimes simply referred to as "conductor 3"), and the first conductor 3a and the second conductor 3b are joined together. This can further enhance conductivity. Also, delamination due to film stress is less likely to occur. Furthermore, it is even more preferable that the first conductor 3a and the second conductor 3b are joined together. Hereafter, the first conductor 3a and the second conductor 3b may be referred to simply as "conductor 3" without distinction from conductor 3.

[0034] (Composition of conductors) The conductor 3 consists of one element selected from the group consisting of Ir, Pt, Rh, Ru, Re, and Mo, or an alloy containing at least one element selected from the group consisting of Ir, Pt, Rh, Ru, Re, and Mo, with a melting point of 1200°C or higher. When metal-encapsulated silica material is used as a heater or various sensors to heat wafers, substrates, etc., it may be used at around 1000°C, but if the conductor 3 is made of the above metal or alloy, the melting or softening of the conductor 3 can be prevented. If the melting or softening of the conductor 3 occurs, discoloration and a decrease in conductivity will occur due to the reaction between the first silica material 1 and the second silica material 2 and the conductor 3. The total content of Ir, Pt, Rh, Ru, Re, and Mo in the alloy is preferably 50% by mass or more, and more preferably 60% by mass or more.

[0035] (Thickness of the conductor) The conductor 3 is a thin film, foil, wire, plate, or strip. The metal-encapsulated silica material is used as a heater for heating wafers, substrates, etc., or as various sensors, and the film thickness, thickness, and wire diameter are adjusted to achieve conductivity according to the intended use. When the conductor 3 is a thin film, the film thickness is preferably 1 μm or less, and more preferably 20 nm to 400 nm. When a first conductor 3a and a second conductor 3b are provided, it is preferable that their total thickness is within the above film thickness range. When the conductor 3 is a foil, the foil thickness is preferably less than 100 μm, and more preferably 8 μm to 70 μm. When the conductor 3 is a wire, the wire diameter is preferably 0.1 mm to 3.0 mm, and more preferably 0.3 mm to 2.0 mm. When the conductor 3 is a plate or strip, the plate or strip thickness is preferably 5.0 mm or less, and more preferably 0.1 mm to 3.0 mm. It should be noted that the classification of foil, plate, or strip is merely a formal distinction based on the thickness of the conductor 3. For example, if the conductor 3 has areas along the surface direction where the thickness is 100 μm or more and areas where it is less than 100 μm, it can be included in any of the concepts of foil, plate, or strip. In this embodiment, forms at such thickness boundaries are formally classified as either plates or strips.

[0036] (A form in which the conductor is a line) When the conductor 3 is a line, for example, there are configurations in which a single line is arranged in parallel within the cavity 12, moving back and forth with gaps between them (for example, a configuration pattern like a planar heating element), configurations in which multiple lines are arranged in parallel with touching surfaces, configurations in which multiple lines are arranged in parallel with gaps between them, and configurations in which a single spiral-shaped line is arranged.

[0037] (A form in which the conductor is a strip) When the conductor 3 is a strip, for example, there are configurations in which one strip is arranged in parallel in a back-and-forth motion with gaps between it and the cavity 12 (for example, a configuration pattern like a planar heating element), configurations in which multiple strips are arranged in parallel in contact with each other, configurations in which multiple strips are arranged in parallel with gaps between them, and configurations in which one spiral-shaped strip is arranged. The ratio of the thickness to the width of the strip is, for example, 1:2 to 1:10, and preferably 1:3 to 1:7.

[0038] (Composition of the first silica material and the second silica material) The first silica material 1 and the second silica material 2 encompass forms such as crystalline silica material or amorphous silica material. They also encompass forms such as synthetic quartz glass plates or fused quartz glass plates. Preferably, the first silica material 1 and the second silica material 2 have a content of 1 ppm or less for each element Li, Na, K, Ca, Mg, B, Fe, and Cu, and an Al content of 10 ppm or less. This can suppress contamination inside the heat treatment furnace. If the content of each element Li, Na, K, Ca, Mg, B, Fe, and Cu in the first silica material 1 and the second silica material 2 exceeds 1 ppm, or if the Al content in the first silica material 1 and the second silica material 2 exceeds 10 ppm, when using metal-encapsulated silica material in a semiconductor heat treatment furnace and heat treating a Si substrate with circuits formed on it, the inside of the heat treatment furnace may become contaminated, potentially rendering the Si substrate unusable.

[0039] (Size and thickness of the first and second silica materials) The shapes of the first silica material 1 and the second silica material 2, as viewed from the front of the conductor 3, are, for example, circular, elliptical, rectangular, or square, with circular being preferred. The diameter of the circle is, for example, 5 to 50 cm. The width of the annular shape of the joint portion 4 between the peripheral edges is preferably, for example, 0.5 to 20 mm. The plate thickness of the first silica material 1 and the second silica material 2 is preferably 0.5 to 10 mm, more preferably 1 to 8 mm. This suppresses energy loss due to heat absorption by the metal-encapsulated silica material itself and improves the thermal responsiveness during heating and cooling of the furnace body. The difference in plate thickness between the first silica material 1 and the second silica material 2 is preferably 5 mm or less, and more preferably the same thickness. If the plate thickness of the first silica material 1 and the second silica material 2 is thinner than 0.5 mm, when using metal-encapsulated silica material in a semiconductor heat treatment furnace and heat treating a Si substrate on which circuits etc. have been formed, there is a risk of damage or deformation due to a decrease in the strength of the metal-encapsulated silica material. On the other hand, if the thickness of the first silica material 1 and the second silica material 2 exceeds 10 mm, when using metal-encapsulated silica material in a semiconductor heat treatment furnace to heat-treat a Si substrate on which circuits and other structures have been formed, the metal-encapsulated silica material, especially the silica material, may absorb heat (thermal radiation, infrared radiation), potentially reducing the thermal efficiency inside the semiconductor heat treatment furnace.

[0040] (Surface roughness of the outer surface of the first silica material and the second silica material) In at least one outer peripheral plane of the first silica material 1 and the second silica material 2, the surface roughness of at least a portion of the outer peripheral plane is preferably such that the arithmetic mean roughness Ra is 5 μm or less. More preferably it is 2 μm or less, even more preferably 1 μm or less, and even more preferably 0.5 μm or less. This facilitates uniform heating of the metal-encapsulated silica material when used in a heater. The lower limit of the arithmetic mean roughness Ra is preferably, for example, 0.01 μm or more, and more preferably 0.1 μm or more. Examples of surfaces with such surface roughness include blast-treated surfaces and etched surfaces. When the outer peripheral plane is a blast-treated surface, the arithmetic mean roughness Ra is preferably 2 μm or less, even more preferably 1 μm or less, and even more preferably 0.5 μm or less. Blasting treatments include wet blasting and dry blasting. Etching treatments include wet etching and dry etching. Furthermore, the degree of arithmetic mean roughness on the outer peripheral plane may be equal or different. For example, there are configurations in which the arithmetic mean roughness Ra of the entire outer peripheral plane is 5 μm or less, or configurations in which the central part of the outer peripheral plane is a smooth surface and the arithmetic mean roughness Ra of the outer ring surrounding the central part is 5 μm or less. A "smooth surface" refers to a surface that has not undergone roughening treatment such as blasting or etching when manufacturing the metal-encapsulated silica material of this embodiment. Furthermore, there are configurations in which the arithmetic mean roughness Ra of the central part of the outer peripheral plane is 2 μm or less and the arithmetic mean roughness Ra of the outer ring surrounding the central part is 5 μm or less, or configurations in which the entire outer peripheral plane is a smooth surface. Furthermore, there are configurations in which the surface of the silica material in the outer peripheral areas other than where the conductor 3 is placed is rougher than the surface of the silica material in the area where the conductor 3 is placed and surrounded by the outer peripheral area. In this case, it is possible to suppress the transmission of heat incident on the outer peripheral area. In this embodiment, the term "outer peripheral plane" is synonymous with "outer plane".

[0041] (OH group content of the first silica material and the second silica material) The OH group content of both the first silica material 1 and the second silica material 2 is 1000 ppm or less, preferably 900 ppm or less, and more preferably 800 ppm or less. If the OH group content of the first silica material 1 and the second silica material 2 exceeds 1000 ppm, deterioration due to the reaction between the conductor 3 and the OH groups will be accelerated, resulting in partial loss or alteration of the conductor, and consequently, discoloration. The lower limit of the OH group content of the first silica material 1 and the second silica material 2 is preferably 1 ppm or more, and preferably 20 ppm or more. If the OH group content is too low, the bonding strength between the silica materials may decrease. Note that there is almost no localized distribution of OH groups in the silica material. The OH group content of silica material varies greatly depending on the manufacturing method, and silica material manufactured by oxyhydrogen melting, in particular, has a high OH group content. If the OH group content of both the first silica material 1 and the second silica material 2 is 1000 ppm or less, they can be used as is. However, if the OH group content is high, it is necessary to reduce the OH group content in the silica material. For example, the first silica material 1 and the second silica material 2 are reduced to 1 Pa or less, preferably 10 -2 from 10 -3The silica material may be fired in a vacuum of Pa at a temperature of 200°C or higher, preferably 1000°C to 1050°C. Firing below 200°C removes surface-adsorbed moisture, but the desorption of hydrogen contained in the silica material is less likely to occur. This is because the decomposition of OH groups contained in the silica material progresses above 970°C. Above 200°C, desorption occurs at temperatures determined by the silica material manufacturing method, but generally, hydrogen is desorbed at 400-700°C, and then desorption continues continuously up to around 1000°C. This desorption increases not only due to the decomposition of hydrogen, but also of moisture and OH groups. Furthermore, at temperatures exceeding 1050°C, the silica material begins to soften. While this softening is advantageous for bonding, it is undesirable because it continuously promotes the desorption of hydrogen, moisture, and OH groups. Therefore, we found that in the temperature range of 200°C to 1050°C, it is possible to remove OH groups contained in the silica material, surface-adsorbed moisture, oxygen contained in the silica material, hydrogen contained in the silica material, and moisture contained in the silica material, thereby preventing deterioration of the conductor after bonding. The OH group content of the silica material is observed as absorption amounts around 2700 nm, 2200 nm, and 1400 nm, and can be confirmed by measuring the absorption amount using a spectrophotometer.

[0042] The method for determining the OH group content of the first silica material 1 and the second silica material 2 is as follows: First, the absorbance was measured using a Fourier transform infrared spectrophotometer (FT-IR). Next, the OH group concentration was determined by dividing the value calculated by applying the absorbance value around 2720 nm to the Lambert-Beer equation by the density.

[0043] (Oxide layer) As shown in Figure 6, when the conductor 3 is a thin film, the metal-encapsulated silica material 300 has an oxide layer 5 between the first silica material 1 and the conductor 3, which contains one oxide selected from the group consisting of silicon oxide, aluminum oxide, lithium tantalate, lithium niobate, magnesium oxide, titanium oxide, yttrium oxide, strontium titanate, germanium oxide, zinc oxide, indium oxide, indium tin oxide, tin oxide, tungsten-doped tin oxide, and tantalum oxide, or an oxide layer 5 containing two or more oxides selected from the group, and it is preferable that the thickness of the oxide layer 5 is 50 nm or less. It is more preferable that the thickness of the oxide layer 5 is 40 nm or less. The metal-encapsulated silica material may also have an oxide layer 5 between the second silica material and the conductor (not shown). Furthermore, as shown in Figure 7, when the conductor 3 is a thin film, the metal-encapsulated silica material 400 may have an oxide layer 5a between the first silica material 1 and the first conductor 3a, and an oxide layer 5b between the second silica material 2 and the second conductor 3b. The adhesion between the conductor 3 (3a, 3b) and the silica materials 1, 2 can be improved by the oxide layer 5 (5a, 5b). As the material of the oxide layer 5 (5a, 5b), a material that further improves the adhesion between the first silica material 1 or the second silica material 2 and the conductor 3 is preferred. Also, if the thickness of the oxide layer 5 (5a, 5b) exceeds 50 nm, the thin film of the conductor may be damaged due to repeated thermal expansion and contraction during use.

[0044] (modified version) The surface opposite to the surface containing the metal, i.e., the outer surface of the metal-encapsulated silica material, is flat, as shown in Figure 2, for example. Furthermore, the first silica material 1 and / or the second silica material 2 may be plate bodies having recesses or protrusions on the surface that becomes the outer surface of the metal-encapsulated silica material. The recesses or protrusions on the plate body can hold a substrate or the like. Figure 8 illustrates an example of using a metal-encapsulated silica material as a heater, such as a susceptor, by fitting a substrate 5, which is the object to be processed, into a metal-encapsulated silica material 500 having a recess 17 for holding the object to be processed on its outer surface. Susceptors include resistance heating type and induction heating type. The substrate 5 is, for example, a substrate to be heat-treated, and is a semiconductor substrate such as silicon. When the outer surface of the substrate 5 is viewed from the front, it is preferable that it has the same shape as the conductor 3, or a shape that does not protrude from the edge of the conductor 3. From a shape viewpoint, the metal-encapsulated silica material according to this embodiment includes being a metal-encapsulated silica plate. In this embodiment, the shape of the metal-encapsulated silica material includes not only the flat plate shape shown in Figures 2 to 7, but also the shape shown in Figure 8, which has a recess or convex portion on at least one of its front or back surfaces. The concept of "plate" encompasses such shapes comprehensively. Furthermore, the concept of "plate" also includes those with curved surfaces. In addition, regarding the shape of the metal-encapsulated silica material, the form in which other components are joined to a flat plate shape, as shown in Figure 9, is also conceptually referred to as a "plate." The metal-encapsulated silica material 70 shown in Figure 9 has a conductive component 13 joined to the metal-encapsulated silica material 50 shown in Figure 2. A conductor 14 is passed through the conductive component 13, and one end of the conductor is connected to one end of the conductor 3. Another conductive component with a different conductor is joined to the other end of the conductor 3. By supplying power to the conductor, the conductor 3 can be energized. Furthermore, the metal-encapsulated silica material can be used as a microheater. An example of use is a donut-shaped metal-encapsulated silica material. First, when the first silica material and the second silica material are joined together, the joined body has a donut shape, and the central part is hollow, that is, it has a shape with an annular hollow section. When this joined body is divided vertically by a plane containing an axis passing through the center of the annular section, for example, the lower part is the first silica material and the upper part is the second silica material.During joining, a roughly annular conductor with a discontinuity is placed between the first and second silica materials. The silica materials with the conductor placed are joined so that the roughly annular conductor is sandwiched between the first and second silica materials, which form a donut shape, and then joined, thereby sealing the conductor. Here, a wire is connected to one end of the roughly annular conductor, which has the discontinuity as one end, and another wire is also connected to the other end, and a conductive component with the wires inserted inside is attached to the silica material containing the conductor. In one configuration, two conductive components are attached, and the wires of the conductive components are connected to one end of the roughly annular conductor and the other end of the roughly annular conductor, respectively. Alternatively, one conductive component is attached, and this conductive component has two paths for inserting wires, with wires passed through each path to one end of the roughly annular conductor and to the other end of the roughly annular conductor, connecting the conductor and the wires. In this way, a donut-shaped metal-encapsulated silica microheater is fabricated. When there are two or more microheaters, they may be connected in the manner described above, or the conductor of one microheater may be connected in series with a conductive component or wire, or the conductors of multiple microheaters may be connected in parallel with a conductive component or wire. The object to be heat-treated is placed in the hollow part of the microheater, and by supplying power to the conductor, the microheater is heated, and the object to be heat-treated can be heated by the heat from the microheater. In other words, the donut-shaped microheater is heated, and the object to be heat-treated placed in the hollow part is heated. The hollow part of the microheater is the hole in the donut. Multiple microheaters can be manufactured and stacked with conductive components attached to them, so that multiple objects to be heat-treated can be heated simultaneously.

[0045] Furthermore, metal-encapsulated silica material can be used as a temperature sensor. (A temperature sensor containing a thermocouple) Two silica materials are prepared, and a pair of conductive materials with different materials or compositions are placed between the two silica materials so that their tips are in contact. The two silica materials are then joined together to create a temperature sensor made of metal-encapsulated silica. The temperature sensor is placed near the object to be heated, and the thermoelectric voltage of the temperature sensor is measured while the object is being heated. In addition, multiple temperature sensors can be prepared and installed for each of the multiple objects to be heated. (A temperature sensor containing two or more thermocouples) A temperature sensor is fabricated that can simultaneously measure the temperature of multiple points on a single object being heated. This sensor is created by preparing two silica materials as a pair and placing two or more conductive materials of different materials or compositions between the two silica materials so that their tips are in contact. The temperature sensor is placed near the object being heated, and the thermoelectric voltage of the temperature sensor is measured while the object is being heated. Alternatively, multiple temperature sensors can be prepared and installed for each of the multiple objects being heated.

[0046] For heaters such as susceptors and microheaters, thin films, foils, wires, plates, or strips are used, while for sensors such as temperature sensors, thin films or wires are used.

[0047] (Manufacturing method in which a conductive material (thin film) is formed on the first silica material) A method for manufacturing the metal-encapsulated silica material 100 will be described with reference to Figure 10. The method for manufacturing the metal-encapsulated silica material 100 includes: a first step of preparing a first silica material 1 and a second silica material 2 as shown in Figure 10(a); a second step of forming a thin film of a conductor 3 on the surface of the first silica material 1 as shown in Figure 10(b); a third step of aligning the surfaces of the first silica material 1 and the second silica material 2 with the surfaces of the conductor 3 formed on the first silica material 1 facing each other as shown in Figure 10(c); and a fourth step of joining at least the peripheral edges of the opposing surfaces of the first silica material 1 and the second silica material 2 as shown in Figure 10(d). The peripheral edges become a joint 4 when joined. In Figure 10(b), a thin film of a conductor 3 is formed on the surface of the first silica material 1, but a thin film of a conductor 3 may also be formed on the surface of the second silica material 2. Since the first silica material 1 and the second silica material 2 are substantially indistinguishable, the diagram here illustrates a configuration in which a conductor 3 is formed on the surface of the first silica material 1.

[0048] (Manufacturing method in which a conductive material (thin film) is formed on the first silica material and the second silica material) A method for manufacturing the metal-encapsulated silica material 200 will be described with reference to Figure 11. The method for manufacturing the metal-encapsulated silica material 200 includes: a first step of preparing a first silica material 1 and a second silica material 2 as shown in Figure 11(e); a second step of forming a thin film of a conductor 3a on the surface of the first silica material 1 and a thin film of a conductor 3b on the surface of the second silica material 2 as shown in Figure 11(f); a third step of aligning the surfaces of the first silica material 1 and the second silica material 2 with the surfaces of the conductor 3a formed on the first silica material 1 and the surfaces of the conductor 3b formed on the second silica material 2 facing each other as shown in Figure 11(g); and a fourth step of joining at least the peripheral edges of the opposing surfaces of the first silica material 1 and the second silica material 2 as shown in Figure 11(h). The peripheral edges become a joint 4 when joined.

[0049] (Manufacturing method including an oxide layer) The manufacturing method for metal-encapsulated silica material 300 will be explained, highlighting the differences from the manufacturing method for metal-encapsulated silica material 100. The manufacturing method for metal-encapsulated silica material 300 includes a first step of preparing the first silica material 1 and the second silica material 2 shown in Figure 10(a), followed by a further step F (not shown) of forming an oxide layer on the surface of the first silica material 1. The oxide layer is preferably formed by sputtering, chemical vapor deposition, or vapor deposition. The manufacturing method then includes a further step G (not shown) of forming a conductor 3 on the oxide layer. The process thereafter proceeds similarly to the third and fourth steps in the manufacturing method for metal-encapsulated silica material 100.

[0050] The manufacturing method for metal-encapsulated silica material 400 will be explained, highlighting the differences from the manufacturing method for metal-encapsulated silica material 200. The manufacturing method for metal-encapsulated silica material 400 includes a first step of preparing the first silica material 1 and the second silica material 2 shown in Figure 11(e), followed by a further step H (not shown) in which an oxide layer is formed on the surface of the first silica material 1 and an oxide layer is formed on the surface of the second silica material 2. The oxide layer is preferably formed by sputtering, chemical vapor deposition, or vapor deposition. The manufacturing method then includes a further step I (not shown) in which a conductor 3 is formed on the oxide layer formed on the first silica material 1 and a conductor 3 is formed on the oxide layer formed on the second silica material 2. The process proceeds in the same manner as the third and fourth steps in the manufacturing method for metal-encapsulated silica material 200.

[0051] (Manufacturing method when the conductive material is foil, wire, plate, or strip) A method for manufacturing metal-encapsulated silica materials 50, 60, 500 includes a first step of preparing a first silica material 1 and a second silica material 2; a second step of preparing a foil, wire, plate, or strip as a conductor 3; a third step of aligning the surfaces of the first silica material 1 and the second silica material 2 and placing the conductor 3 between them; and a fourth step of joining at least the peripheral edges of the opposing surfaces of the first silica material 1 and the second silica material 2. Here, it is preferable that at least one of the first silica material 1 and the second silica material 2 has a cavity 12, and that the conductor 3 is housed in the cavity 12. Furthermore, a recess in the cavity may be formed according to the shape of the conductor. For example, it may be a congruent shape or a similar shape.

[0052] In the manufacturing method of metal-encapsulated silica materials 50, 60, 100, 200, 300, 400, and 500, it is preferable to perform a fifth step after the fourth step in which the outer surface of the first silica material 1 and the second silica material 2 is polished to adjust the final plate thickness. This allows for more precise adjustment of the final plate thickness. The metal-encapsulated silica materials 50, 60, 100, 200, 300, 400, and 500 are adjusted so that their plate thickness is, for example, 1.0 to 20 mm. In addition, the plate thicknesses of the first silica material 1 and the second silica material 2 are adjusted so that they are each 0.5 to 10 mm.

[0053] In the manufacturing method of metal-embedded silica materials 50, 60, 100, 200, 300, 400, and 500, it is preferable that in the fourth step, after creating an atmosphere of either a vacuum atmosphere of 100 Pa or less, an argon atmosphere, or a nitrogen atmosphere, the first silica material 1 and the second silica material 2 are joined at a pressure of 10 MPa or less and a temperature of 400 to 1000°C. This suppresses the deterioration of the conductor due to oxygen and hydrogen, as well as the deterioration of the conductor due to heat, and maintains conductivity. Although welding with an oxyhydrogen burner can also be performed, temperature control is difficult, and furthermore, high temperatures of 1000°C or higher are required for joining, which causes the conductor 3 to deteriorate and leads to a decrease in conductivity. The argon atmosphere or nitrogen atmosphere may be an argon atmosphere under reduced pressure lower than atmospheric pressure or a nitrogen atmosphere under reduced pressure, but atmospheric pressure may also be used. Furthermore, if the vacuum atmosphere exceeds 100 Pa, impurities remaining in the atmosphere will adhere to the surfaces of the first silica material 1, the second silica material 2, and the conductor 3 during the subsequent bonding process. When manufacturing the metal-encapsulated silica materials 50, 60, 100, 200, 300, 400, and 500, these impurities may come into contact with the surface of the conductor 3 and react, potentially leading to deterioration of the conductor 3. Additionally, when the manufactured metal-encapsulated silica materials 50, 60, 100, 200, 300, 400, and 500 are used in semiconductor heat treatment furnaces, etc., these impurities may be scattered into the semiconductor heat treatment furnaces, etc. When a vacuum atmosphere of 100 Pa or less is used, it is preferable to use a vacuum atmosphere of 80 Pa or less. If the pressure pressing the first silica material 1 and the second silica material 2 together exceeds 10 MPa, the pressure will be excessive, potentially causing defects such as cracking of the first silica material 1 and the second silica material 2. The pressure at which the first silica material 1 and the second silica material 2 are pressed together is more preferably 8 MPa or less. The lower limit of this pressure is preferably 1 MPa or more, and more preferably 2 MPa or more, in order to ensure reliable bonding. Furthermore, if the bonding temperature is lower than 400°C, the bonding strength between the first silica material 1 and the second silica material 2 will be insufficient, and there is a risk that delamination of the first silica material 1 and the second silica material 2 may occur when the manufactured metal-encapsulated silica materials 50, 60, 100, 200, 300, 400, and 500 are used in semiconductor heat treatment furnaces or the like.Furthermore, if the bonding temperature is higher than 1000°C, clouding of the conductor 3 may occur, potentially reducing its conductivity. The bonding temperature is preferably 500 to 900°C, and more preferably 600 to 850°C.

[0054] (Spacer) In the manufacturing method of metal-encapsulated silica materials 50, 60, 100, 200, 300, 400, and 500, it is preferable to further include step A between the third and fourth steps, as shown in Figure 10(d) or Figure 11(h), in which a spacer made of carbon, oxide, nitride, or boride, or a spacer 6 containing at least one selected from the group consisting of carbon, oxide, nitride, and boride, is placed at a location that contacts at least the outer surface of the first silica material 1 and the second silica material 2. This allows the first silica material and the second silica material to be joined while suppressing contamination of the conductor by impurities. The spacer 6 is, for example, a plate material such as a flat plate or a curved plate. The shape and size of the spacer 6 are preferably similar or congruent to the first silica material and the second silica material, and when similar, they may be increased by up to +10%. The thickness of the spacer 6 is preferably 1 to 70 mm, and more preferably 30 to 50 mm. When bonding, it is necessary for the components of the pressurizer to come into contact with the first silica material 1 and the second silica material 2. However, if a spacer made of a material other than "a spacer made of carbon, oxide, nitride, or boride, or a spacer containing at least one selected from the group consisting of carbon, oxide, nitride, and boride" is used, there is a risk that it may react with the first and second silica materials and deteriorate. Furthermore, when the manufactured metal-encapsulated silica materials 50, 60, 100, 200, 300, 400, and 500 are used in semiconductor heat treatment furnaces or the like, there is a risk that they may adversely affect semiconductor substrates.

[0055] (Press again) As shown in Figure 12, the method for manufacturing the metal-encapsulated silica material 100 according to this embodiment further includes a step B (Figure 12(c-1)) between the third and fourth steps, in which a plurality of stacked bodies are prepared, each consisting of a first silica material and a second silica material obtained in the third step and a spacer placed at a location that contacts at least the outer peripheral plane of the first silica material and the second silica material, and 2 to 30 sets of these stacked bodies are stacked in the stacking direction to form a stacked body, wherein the spacer 7 is made of carbon, oxide, nitride or boride, or includes at least one selected from the group consisting of carbon, oxide, nitride and boride, and the fourth step is preferably a step in which 2 to 30 sets of the stacked first silica material and second silica material are joined simultaneously (Figure 12(d-1)). Furthermore, as shown in Figure 13, the method for manufacturing the metal-encapsulated silica material 200 according to this embodiment further includes a step B (Figure 13(g-1)) between the third and fourth steps, in which multiple stacked bodies are prepared, each consisting of a first silica material and a second silica material obtained in the third step and a spacer placed at a location that contacts at least the outer peripheral plane of the first silica material and the second silica material, and 2 to 30 sets of these stacked bodies are stacked in the stacking direction to form a stacked body, wherein the spacer 7 is made of carbon, oxide, nitride, or boride, or includes at least one selected from the group consisting of carbon, oxide, nitride, and boride, and the fourth step is preferably a step (Figure 13(h-1)) in which 2 to 30 sets of the stacked first silica material and second silica material are joined simultaneously. If the number of stacked layers exceeds 30, handling may be impaired. Similarly, for metal-encapsulated silica materials 50, 60, 300, 400, and 500, process B is performed, and multiple layers can be joined simultaneously in the fourth process. The shape and size of the spacer 7 are preferably similar or congruent to the first and second silica materials, and if similar, they may be increased by up to +10%.The thickness of the spacer 7 is preferably 1 to 70 mm, and more preferably 30 to 50 mm.

[0056] In the manufacturing method of the metal-encapsulated silica materials 50, 60, 100, 200, 300, 400, and 500 according to this embodiment, the material of the spacer is carbon, which is preferable because, due to its self-lubricating properties, it does not cause damage even when in contact with the silica material during bonding. The carbon has a sodium and potassium content of 3 ppm or less each, an iron and boron content of 1 ppm or less each, and a copper content of 0.1 ppm or less. Furthermore, it is preferable that the spacer is a spacer containing glassy carbon, a spacer made of glassy carbon, a spacer with glassy carbon coated on part or all of its surface, or a spacer with pyrolysis carbon coated on part or all of its surface. This can reduce particle generation from the carbon.

[0057] In the manufacturing method of the metal-encapsulated silica materials 50, 60, 100, 200, 300, 400, and 500 according to this embodiment, when forming the conductor 3 (3a, 3b) as a thin film in the second step, it is preferable to form it by sputtering, chemical vapor deposition, or evaporation. This allows for a uniform thickness of the conductor. Furthermore, it is possible to improve the density of the film, thereby improving conductivity.

[0058] In the manufacturing method of the metal-encapsulated silica materials 50, 60, 100, 200, 300, 400, and 500 according to this embodiment, it is preferable to further include a step C between the first and second steps, in which the surfaces of the first silica material 1 and the second silica material 2 that are to be placed facing each other in the third step are reverse sputtered. By removing impurities from the opposing surfaces of the first silica material and the second silica material, the adhesion between the first silica material and the conductive thin film, the first silica material and the oxide layer, the second silica material and the conductive thin film, and the second silica material and the oxide layer is improved. When the conductor is a thin film, foil, wire, plate, or strip, the adhesion of the joint between the first silica material and the second silica material at the periphery can be improved. By removing impurities, it is possible to suppress the deterioration of the conductor 3 caused by the contact and reaction between impurities on the surfaces of the first silica material 1 and the second silica material 2 and the surface of the conductor 3. In addition, the adhesion of the film formation is improved due to the anchoring effect.

[0059] In the manufacturing method of the metal-encapsulated silica materials 50, 60, 100, 200, 300, 400, and 500 according to this embodiment, it is preferable to further include at least one step selected from the group consisting of a D step, in which heat treatment is performed at 1000°C or lower after the second step, and an E step, in which heat treatment is performed at 1200°C or lower after the fourth step. The lower limit temperature for the heat treatment is, for example, 100°C or higher, and preferably 200°C or higher. Both the D step and the E step may be included. Furthermore, in the fourth step, when heating at 400 to 1000°C is performed during bonding, bonding and heat treatment are performed simultaneously. The density of the conductor 3 can be improved. When the conductor is a thin film, sufficient conductivity cannot be obtained if the density of the thin film at the time of film formation is insufficient, but by performing heat treatment, the thin film becomes denser and exhibits the desired conductivity. On the other hand, if heat treatment is performed at a temperature higher than 1200°C, there is a risk that a reaction will occur between the first silica material 1, the second silica material 2 and the conductor 3 (3a, 3b). [Examples]

[0060] (Example 1) As the first silica material 1 and the second silica material 2, silica materials (synthetic quartz plates) with a plate size of approximately 300 mm in diameter and 1.0 mm in thickness were used, with Li, Na, K, Ca, Mg, B, Fe, and Cu at concentrations of 1 ppm or less, Al at 10 ppm or less, and an OH group concentration of 1000 ppm. The silica material had a cut-off portion along the chord of the circle (the same applies to the disc-shaped silica material in the following examples and comparative examples). Impurities were quantified using an ICP mass spectrometer, and the OH groups were further quantified using a Fourier transform infrared spectrophotometer (JASCO, PS-4000). After surface cleaning of these silica materials, 100 nm thick Mo films were deposited on the first silica material 1 and the second silica material 2, respectively, by sputtering, as conductors 3a and 3b. The two silica materials were bonded together with the thin films facing inward. A carbon spacer coated with glassy carbon containing 0.1 ppm sodium, 1 ppm potassium, 1 ppm iron, 0.1 ppm boron, and 0.1 ppm copper was placed in contact with the outer surface of the first silica material 1. A carbon spacer coated with glassy carbon containing 0.1 ppm sodium, 1 ppm potassium, 1 ppm iron, 0.1 ppm boron, and 0.1 ppm copper was placed in contact with the outer surface of the second silica material 2. The two materials were then set in an atmosphere-controlled pressurizer. Vacuum was applied, and the materials were bonded under conditions of a 10 Pa vacuum atmosphere, a temperature of 800°C, and a pressure of 2 MPa for 3 hours. After bonding, the thin films were visually inspected for discoloration, and no discoloration was observed. Furthermore, visual inspection of the bond between the first silica material 1 and the second silica material 2 revealed no delamination between the two materials.

[0061] (Example 2) The metal-embedded silica material prepared in Example 1 was placed in a vacuum annealing furnace (manufactured by ULVAC Riko Co., Ltd.) and the pressure was increased to 1.0 × 10⁻⁶ ‐4 A heat treatment was performed in a vacuum atmosphere of Pa, with the temperature raised to 800°C and held for 20 minutes. After the heat treatment, the metal-embedded silica material was visually inspected for any discoloration of the thin film, and no discoloration was observed. Furthermore, visual inspection of the bonding between the first silica material 1 and the second silica material 2 revealed no delamination between the first and second silica materials.

[0062] (Comparative Example 1) As the first silica material 1 and the second silica material 2, silica materials (synthetic quartz plates) with a plate size of approximately 300 mm in diameter and 1.0 mm in thickness were used, with Li, Na, K, Ca, Mg, B, Fe, and Cu at concentrations of 1 ppm or less, Al at 10 ppm or less, and an OH group concentration of 1200 ppm. Impurities were quantified using an ICP mass spectrometer, and the OH groups were further quantified using a Fourier transform infrared spectrophotometer. After surface cleaning of these silica materials, 100 nm thick Mo films were deposited on the first silica material 1 and the second silica material 2, respectively, by sputtering, as conductors 3a and 3b. The two materials were bonded together with the thin films facing inward, and carbon spacers made of carbon were placed in contact with the outer surface of the first silica material 1 and the outer surface of the second silica material 2, and then set in an atmosphere-controlled pressurizer. The materials were vacuum-filled and bonded under conditions of a 10 Pa vacuum, 800°C, and 0.8 MPa pressure for 1 hour. After bonding, visual inspection revealed some discoloration of the thin film. Furthermore, visual inspection of the bond between the first silica material 1 and the second silica material 2 revealed some unbonded areas in both the first and second silica materials.

[0063] (Example A) As the first silica material 1, a silica material (synthetic quartz plate) with a plate size of approximately 300 mm in diameter and a thickness of 1.03 mm was used, with an OH group concentration of 912.39 ppm, Li, Na, K, Ca, Mg, B, Fe, and Cu at 1 ppm or less, and Al at 10 ppm or less. As the second silica material 2, a silica material (synthetic quartz plate) with a plate size of approximately 300 mm in diameter and a thickness of 1.04 mm was used, with an OH group concentration of 926.50 ppm, Li, Na, K, Ca, Mg, B, Fe, and Cu at 1 ppm or less, and Al at 10 ppm or less. Otherwise, the metal-embedded silica material was prepared in the same manner as in Example 1. After bonding, the presence or absence of discoloration of the thin film was checked visually, and no discoloration was observed. Furthermore, visual inspection of the bonding between the first silica material 1 and the second silica material 2 revealed no delamination between the first and second silica materials.

[0064] (Example B-1) Susceptor with a spiral-shaped conductive band housed in a cavity on one side As the first silica material 1, a silica material (fused silica plate) was used with a plate size of approximately 324 mm in diameter and 5.04 mm in thickness, with an OH group concentration of 256.59 ppm, Li, Na, K, Ca, Mg, B, Fe, Cu at 1 ppm or less, and Al at 10 ppm or less. As the second silica material 2, a silica material (fused silica plate) was used with a plate size of approximately 324 mm in diameter and 5.04 mm in thickness, with an OH group concentration of 245.77 ppm, Li, Na, K, Ca, Mg, B, Fe, Cu at 1 ppm or less, and Al at 10 ppm or less. 5 mm from the outer edge of the first silica material plate surface was left as a joining area, and using a cutting method, spiral recessed cavities with a depth of 1.5 mm and a width of 2 mm were formed in a clockwise direction from the outside toward the center of gravity, with a gap of about 4 mm between them. Once the cavity reached the center of gravity, spiral recessed cavities with a depth of 1.5 mm and a width of 2 mm were formed in the uncut areas in a counterclockwise direction toward the center of gravity, with a gap of about 1 mm between them. Next, a conductive strip with a thickness of 1.3 mm and a width of 1.8 mm was embedded along the cavity. At this time, the outer end of the conductive strip of the metal-encapsulated silica material becomes the point where the power supply and the conductive strip of the metal-encapsulated silica material are connected with a conductive component, or where two conductive strips of metal-encapsulated silica material are connected with a conductive component. Otherwise, the metal-encapsulated silica material susceptor was fabricated in the same manner as in Example 1. After bonding, the condition of the strip was visually inspected and no abnormalities were found. Furthermore, visual inspection of the bonding between the first silica material 1 and the second silica material 2 revealed no delamination between the first and second silica materials. Next, the susceptor was installed in the semiconductor heat treatment apparatus with the conductive strip end of the susceptor connected to the conductive component of the semiconductor heat treatment apparatus. A silicon wafer with a diameter of approximately 300 mm and a thickness of 1 mm was placed on the top surface of the susceptor, and it was confirmed that electricity could be passed through the conductive material of the susceptor to heat it to approximately 800°C, thereby heating the silicon wafer placed on the top surface of the susceptor.

[0065] (Example B-2) A susceptor of Example B-1 with a recess formed on the upper surface for mounting a silicon wafer. A metal-encapsulated silica susceptor was fabricated in the same manner as in Example B-1, except that a cavity with a diameter of approximately 300 mm and a depth of 0.5 mm was formed on the outer surface of the second silica material of the metal-encapsulated silica material of Example B-1 by machining. After bonding, the condition of the strip was visually inspected and no abnormalities were found. Furthermore, visual inspection of the bonding between the first silica material 1 and the second silica material 2 revealed no delamination between the first and second silica materials. Next, the susceptor was installed in a semiconductor heat treatment apparatus with the conductive strip end of the susceptor connected to the conductive component of the semiconductor heat treatment apparatus. A silicon wafer with a diameter of approximately 300 mm and a thickness of 1 mm was placed in the cavity on the upper surface of the susceptor, and it was confirmed that power could be supplied to the conductor of the susceptor to heat it to approximately 800°C, thereby heating the silicon wafer placed on the upper surface of the susceptor.

[0066] (Example C-1) Wafer thermocouple with thermocouple wire housed in a cavity As the first silica material 1, a silica material (synthetic quartz plate) was used with a plate size of approximately 324 mm in diameter and 3.22 mm in thickness, with an OH group concentration of 71.60 ppm, Li, Na, K, Ca, Mg, B, Fe, Cu at 1 ppm or less, and Al at 10 ppm or less. As the second silica material 2, a silica material (synthetic quartz plate) was used with a plate size of approximately 324 mm in diameter and 1.23 mm in thickness, with an OH group concentration of 71.60 ppm, Li, Na, K, Ca, Mg, B, Fe, Cu at 1 ppm or less, and Al at 10 ppm or less. In Example C-1, the second silica material 2 serves as a lid, so its thickness may be thinner than that of the first silica material 1. Two cavities with a depth of 0.8 mm and a width of 0.8 mm were formed using a laser processing method at the center of gravity of the first silica material's plate surface, up to 5 mm from the outer edge that would remain as a joint. At this point, the two cavities are connected at their center of gravity. Next, the ends of a 0.5 mm diameter Pt wire and a 0.5 mm diameter PtRh wire were welded together, and the ends of the Pt and PtRh wires were placed at the center of gravity of the cavities. The remaining Pt and PtRh wires were then embedded one in each cavity. At this point, the wire ends opposite the welded ends of the Pt and PtRh wires become the points where the voltmeter and the conductive wire of the metal-encapsulated silica material are connected with a conductive component. Otherwise, the metal-encapsulated silica wafer thermocouple was fabricated in the same manner as in Example 1. After joining, the thermocouple was visually inspected and no abnormalities such as wire breaks were found. Furthermore, visual inspection of the joint between the first silica material 1 and the second silica material 2 revealed no delamination between the first and second silica materials. Next, with the wire ends of the wafer thermocouple connected to the conductive components of the semiconductor heat treatment apparatus, the wafer thermocouple was placed near the location where the substrate to be heat-treated would be placed in the semiconductor heat treatment apparatus. A silicon wafer with a diameter of approximately 300 mm and a thickness of 1 mm was then placed at the location where the substrate to be heat-treated would be placed, and when the semiconductor heat treatment apparatus was heated to approximately 800°C, it was confirmed that the temperature measured by the wafer thermocouple was approximately 800°C.

[0067] (Example C-2) Wafer thermocouple with a thin film of thermocouple housed in a cavity In Example C-1, two cavities with a depth of 0.05 mm and a width of 0.8 mm were formed using a laser processing method at the center of gravity of the metal-encapsulated silica material, extending 5 mm from the outer edge to be left as the bonding point. At this time, the two cavities were connected at the center of gravity. Subsequently, a Pt film with a thickness of 500 nm and a width of 0.8 mm was deposited in one cavity instead of a Pt wire with a diameter of 0.5 mm, and a PtRh film with a thickness of 500 nm and a width of 0.8 mm was deposited in the other cavity instead of a PtRh wire with a diameter of 0.5 mm, in the same manner as in Example C-1. After bonding, the condition of the thermocouple was visually inspected and no abnormalities were observed. Furthermore, visual inspection of the bonding between the first silica material 1 and the second silica material 2 revealed no delamination between the first and second silica materials. Next, with the thin film end of the wafer thermocouple connected to a conductive component of the semiconductor heat treatment apparatus, the wafer thermocouple was placed near the location where the substrate to be heat-treated would be placed in the semiconductor heat treatment apparatus. A silicon wafer with a diameter of approximately 300 mm and a thickness of 1 mm was then placed at the location where the substrate to be heat-treated would be placed, and when the semiconductor heat treatment apparatus was heated to approximately 800°C, it was confirmed that the temperature measured by the wafer thermocouple was approximately 800°C.

[0068] (Example D-1) A 100 nm Rh film was deposited in the cavity. For the first silica material 1, a silica material (synthetic quartz plate) with a plate size of 20 mm x 40 mm and a thickness of 1.02 mm was used, with an OH group concentration of 888.48 ppm, Li, Na, K, Ca, Mg, B, Fe, Cu at 1 ppm or less, and Al at 10 ppm or less. For the second silica material 2, a silica material (synthetic quartz plate) with a plate size of 20 mm x 40 mm and a thickness of 1.03 mm was used, with an OH group concentration of 956.99 ppm, Li, Na, K, Ca, Mg, B, Fe, Cu at 1 ppm or less, and Al at 10 ppm or less. 5 mm from the outer edge of the plate surfaces of the first silica material 1 and the second silica material 2 was left as a joining area, and a cavity with a depth of 200 nm was formed in the remaining area using an etching method. A metal-embedded silica material was fabricated in the same manner as in Example 1, except that Rh films were deposited as conductive materials 3a and 3b to a thickness of 100 nm in the formed cavities, and the materials were held for 3 hours under the conditions of a vacuum chamber with an atmosphere of 10 Pa or less, a temperature of 900°C, and a pressure of 2 MPa. After bonding, the thin films were visually inspected for discoloration, and no discoloration was observed. Furthermore, visual inspection of the bonding between the first silica material 1 and the second silica material 2 revealed no delamination between the first and second silica materials.

[0069] (Example D-2) A 10nm TiO2 layer / 50nm Ir layer laminated film was deposited in the cavity. In the metal-embedded silica material of Example D-1, only the first silica material 1 was left with a 5 mm gap from the outer edge of the plate surface as a bonding area, and a cavity with a depth of 200 nm was formed in the remaining area using an etching method. No film was deposited on the second silica material 2. A TiO2 layer with a thickness of 10 nm was deposited only in the cavity formed on the first silica material, and then an Ir layer with a thickness of 50 nm was deposited on top of the TiO2 layer as a conductor 3a using a sputtering method to create a laminated film. Otherwise, the metal-embedded silica material was prepared in the same manner as in Example D-1. After bonding, the presence or absence of discoloration of the thin film was checked visually, and no discoloration was observed. Visual inspection revealed no delamination between the first silica material and the second silica material.

[0070] (Example D-3) A multilayer film of 10nm TiO2 layer / 50nm Ru layer is deposited in the cavity. In the metal-embedded silica material of Example D-1, only the second silica material 2 was left with a 5mm gap from the outer edge of the plate surface as a bonding area, and a cavity with a depth of 200nm was formed in the remaining area using an etching method. No film was deposited on the first silica material 1. A TiO2 layer with a thickness of 10nm was deposited only in the cavity formed on the second silica material, and then a Ru layer with a thickness of 50nm was deposited on top of the TiO2 layer as a conductor 3b using a sputtering method to create a laminated film. Otherwise, the metal-embedded silica material was prepared in the same manner as in Example D-1. After bonding, the presence or absence of discoloration of the thin film was checked visually, and no discoloration was observed. Visual inspection revealed no delamination between the first and second silica materials.

[0071] (Example E) Effect of arithmetic mean roughness Ra For the first silica material 1, a silica material (synthetic quartz plate) with a plate size of 20 mm x 40 mm and a thickness of 1.03 mm was used, with an OH group concentration of 941.06 ppm, Li, Na, K, Ca, Mg, B, Fe, Cu at 1 ppm or less, and Al at 10 ppm or less. For the second silica material 2, a silica material (synthetic quartz plate) with a plate size of 20 mm x 40 mm and a thickness of 1.03 mm was used, with an OH group concentration of 981.08 ppm, Li, Na, K, Ca, Mg, B, Fe, Cu at 1 ppm or less, and Al at 10 ppm or less. As conductors 3a and 3b, Mo films were deposited to a thickness of 50 nm, respectively. Except for the conditions in the atmosphere-controlled pressurizer, which involved vacuuming and holding for 3 hours under a vacuum atmosphere of 10 Pa or less, a temperature of 850°C, and a pressurization of 3 MPa, metal-embedded silica materials were prepared in the same manner as in Example 1. After preparation, the arithmetic mean roughness Ra of the metal-embedded silica material was measured using a surface roughness meter (Mitutoyo Corporation, model 178-560-11). Subsequently, the metal-embedded silica material was subjected to blast treatment, and the arithmetic mean roughness Ra of the metal-embedded silica material with its surface roughened by blast treatment was measured repeatedly until the arithmetic mean roughness Ra was 5 μm or less. The OH group concentration was measured before and after blasting, and no change in concentration occurred. The obtained metal-embedded silica material was placed in a heating device, and the surface of the metal-embedded silica material heated to 800°C was measured using thermography, confirming a uniform heat distribution.

[0072] (Example F-1) Each Mo film has a thickness of 25 nm. For the first silica material 1, a silica material (synthetic quartz plate) with a plate size of 20 mm x 40 mm and a thickness of 1.04 mm was used, with an OH group concentration of 962.35 ppm, Li, Na, K, Ca, Mg, B, Fe, Cu at 1 ppm or less, and Al at 10 ppm or less. For the second silica material 2, a silica material (synthetic quartz plate) with a plate size of 20 mm x 40 mm and a thickness of 1.02 mm was used, with an OH group concentration of 904.67 ppm, Li, Na, K, Ca, Mg, B, Fe, Cu at 1 ppm or less, and Al at 10 ppm or less. As conductors 3a and 3b, Mo films were deposited to a thickness of 25 nm, respectively. Except for the conditions in the atmosphere-controlled pressurizer, which involved vacuuming and holding for 3 hours under a vacuum atmosphere of 10 Pa or less, a temperature of 850°C, and a pressurization of 3 MPa, metal-embedded silica materials were prepared in the same manner as in Example 1. After bonding, visual inspection was performed to check for discoloration of the thin film, and no discoloration was observed. Furthermore, visual inspection of the bonding between the first silica material 1 and the second silica material 2 revealed no delamination between the first and second silica materials.

[0073] (Example F-2) Each Mo film has a thickness of 50 nm Regarding the metal-embedded silica material of Example F-1, the metal-embedded silica material was prepared in the same manner as in Example F-1, except that Mo films were deposited on each of the conductive materials 3a and 3b to a thickness of 50 nm. After bonding, the thin films were visually inspected for discoloration, and no discoloration was observed. Furthermore, visual inspection of the bonding between the first silica material 1 and the second silica material 2 revealed no delamination between the first and second silica materials. [Explanation of symbols]

[0074] 1. First Silica Material 2. Second Silica Material 3. Conductors 3a First conductor 3b Second conductor 4 Joint 5,5a,5b oxide layer 6 Spacers 7 Spacers 12 Cavity 13 Conductive components 14 Conductor 50, 60, 70, 100, 200, 300, 400, 500 Metal-embedded silica material

Claims

1. First silica material and, A second silica material whose surface is facing the first silica material, A conductor disposed between the first silica material and the second silica material, A metal-encapsulated silica material comprising a joint portion in which at least the peripheral edge of the mating surface between the first silica material and the second silica material is joined in a continuous annular manner along the periphery, The OH group content of the first silica material and the second silica material is 1000 ppm or less. The conductor is a thin film, foil, wire, plate, or strip, and The conductor is characterized by being composed of one selected from the group consisting of Ir, Pt, Rh, Ru, Re, and Mo, or an alloy containing at least one selected from the group consisting of Ir, Pt, Rh, Ru, Re, and Mo, and having a melting point of 1200°C or higher.

2. The metal-encapsulated silica material according to claim 1, characterized in that it is a heater or a sensor.

3. The metal-encapsulated silica material according to claim 1 or 2, characterized in that the first silica material and the second silica material have a content of 1 ppm or less of each element Li, Na, K, Ca, Mg, B, Fe, and Cu, and an Al content of 10 ppm or less.

4. The metal-encapsulated silica material according to claim 1 or 2, characterized in that, in at least one outer peripheral plane of the first silica material and the second silica material, the surface roughness of at least a portion of the outer peripheral plane has an arithmetic mean roughness Ra of 5 μm or less.

5. The metal-encapsulated silica material according to claim 1 or 2, characterized in that at least one of the first silica material and the second silica material has cavities on opposing surfaces, and the conductor is housed in the cavity.

6. The metal-encapsulated silica material according to claim 1 or 2, characterized in that at least one of the first silica material and the second silica material has a recess on its outer peripheral plane for holding an object to be processed.

7. The metal-encapsulated silica material according to claim 1 or 2, characterized in that the thickness of the first silica material and the second silica material is 0.5 to 10 mm.

8. The thickness of the thin film is 1 μm or less. The thickness of the foil is less than 100 μm. The diameter of the aforementioned wire is 0.1 to 3 mm. The thickness of the aforementioned plate is 5 mm or less. The metal-encapsulated silica material according to claim 1 or 2, characterized in that the thickness of the aforementioned band is 5 mm or less.

9. The aforementioned conductor is a thin film, The metal-embedded silica material has, at least one location between the first silica material and the conductor, and between the second silica material and the conductor, an oxide layer containing one selected from the group of oxides consisting of silicon oxide, aluminum oxide, lithium tantalate, lithium niobate, magnesium oxide, titanium oxide, yttrium oxide, strontium titanate, germanium oxide, zinc oxide, indium oxide, indium tin oxide, tin oxide, tungsten-doped tin oxide, and tantalum oxide, or an oxide layer containing two or more selected from the group of oxides, and The metal-embedded silica material according to claim 1 or 2, characterized in that the thickness of the oxide layer is 50 nm or less.

10. A method for producing a metal-encapsulated silica material according to claim 1, The first step involves preparing a first silica material and a second silica material, A second step of preparing a foil, wire, plate, or strip as the conductor, or forming a thin film as the conductor on at least one of the surfaces of the first silica material and the second silica material, A third step involves aligning the surfaces of the first silica material and the second silica material and placing the conductor between the first silica material and the second silica material, A fourth step of joining at least the peripheral edges of the opposing surfaces of the first silica material and the second silica material, A method for producing a metal-encapsulated silica material, characterized by containing the following:

11. The method for manufacturing a metal-encapsulated silica material according to claim 10, characterized in that, after the fourth step, a fifth step is performed in which the outer surface of the first silica material and the second silica material is polished to adjust the final plate thickness.

12. In the above fourth step, The method for manufacturing a metal-encapsulated silica material according to claim 10, characterized in that the first silica material and the second silica material are bonded at a pressure of 10 MPa or less and a temperature of 400 to 1000°C after being placed in a vacuum atmosphere of 100 Pa or less, an argon atmosphere, or a nitrogen atmosphere.

13. The method for manufacturing a metal-encapsulated silica material according to claim 10, further comprising step A between the third step and the fourth step, wherein a spacer made of carbon, oxide, nitride, or boride, or a spacer containing at least one selected from the group consisting of carbon, oxide, nitride, and boride, is placed at a location in contact with at least the outer surface of the first silica material and the second silica material.

14. Between the third and fourth steps, a further step B is included in which a plurality of stacked bodies are prepared, each consisting of a first silica material and a second silica material obtained in the third step, and a spacer placed at a location that contacts at least the outer surface of the first silica material and the second silica material, and 2 to 30 sets of these stacked bodies are stacked in the stacking direction to form a stacked body. The spacer consists of carbon, oxide, nitride, or boride, or includes at least one selected from the group consisting of carbon, oxide, nitride, and boride. The method for manufacturing a metal-encapsulated silica material according to claim 10, characterized in that the fourth step is a step of simultaneously joining 2 to 30 stacks of the first silica material and the second silica material.

15. The material of the spacer is carbon, and the carbon has a sodium and potassium content of 3 ppm or less each, an iron and boron content of 1 ppm or less each, and a copper content of 0.1 ppm or less, The method for producing a metal-encapsulated silica material according to claim 13 or 14, characterized in that the spacer is a spacer containing glassy carbon, a spacer made of glassy carbon, a spacer with glassy carbon coated on part or all of its surface, or a spacer with pyrolysis carbon coated on part or all of its surface.

16. The method for producing a metal-encapsulated silica material according to claim 10, characterized in that the thin film is formed in the second step by any of the following methods: sputtering, chemical vapor deposition, or vapor deposition.

17. The method for manufacturing a metal-encapsulated silica material according to claim 10, further comprising step C between the first step and the second step, in which the surfaces of the first silica material and the second silica material that are to be placed facing each other in the third step are reverse sputtered.

18. The method for producing a metal-encapsulated silica material according to claim 10, further comprising at least one step selected from the group consisting of step D, which involves heat treatment at 1000°C or less after the second step, and step E, which involves heat treatment at 1200°C or less after the fourth step.

Images