Vacuum device manufacturing method

Abstract

To facilitate formation of a vacuum chamber.SOLUTION: While the inside of a vacuum heating furnace in which a vacuum device is disposed is evacuated to a high vacuum, the vacuum device is heated to a temperature A to degas the inside of a chamber R3, and then the vacuum device is heated to a temperature C in the high vacuum and keeps the temperature C. By the heating, a cylindrical member is softened, deformed by own weight, calcined and changed into a sealing part for sealing a through-hole of a housing. Thereby, the chamber in the housing of the vacuum device becomes a vacuum chamber. Subsequently, the temperature of the vacuum device is lowered, and the temperature of the vacuum device is kept at a temperature B, a softening point or less of the sealing part and a glass-transition point or more, to activate getters in the chamber. By activating the getters, the degree of vacuum of the chamber that becomes the vacuum chamber is improved.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a vacuum device having a vacuum chamber, and to a vacuum device. [Background technology]

[0002] The vacuum chamber of the vacuum device is formed, for example, by a method as disclosed in Patent Document 1. First, a vacuum is drawn to a room that will become the vacuum chamber (reference pressure chamber 7) through a pipe (vacuum drawing pipe 9) that communicates with the room. After that, a part of the pipe is pressurized and deformed, and the pressurized and deformed part is welded and sealed by resistance welding to form the vacuum chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 63-133032 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional method of forming a vacuum chamber disclosed in Patent Document 1, it is necessary to physically deform the pipe after evacuation to seal it, which makes the formation of the vacuum chamber time-consuming.

[0005] An object of the present invention is to make it possible to easily form a vacuum chamber. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, a manufacturing method for a vacuum device according to a first aspect of the present invention includes a first step of forming a vacuum device before a vacuum chamber is formed, the vacuum device comprising: a housing having a chamber therein which serves as a vacuum chamber, the housing having a through hole connecting the chamber to the outside of the housing; and a member disposed in the through hole and having a connecting passage connecting the chamber to the outside of the housing; and a second step of evacuating gas within a vacuum heating furnace that houses the vacuum device to evacuate gas within the chamber from the chamber through the connecting passage, and heating and softening the member in the vacuum heating furnace to deform the member under its own weight and seal the through hole, thereby forming the vacuum chamber.

[0007] The vacuum device formed in the first step may include a getter in the chamber that is activated when heated, and in the second step, the vacuum device may be heated in the vacuum heating furnace to activate the getter even after the member has deformed to seal the through hole.

[0008] In the second step, the vacuum device may be heated at a first heating temperature to soften and deform the member, and then the vacuum device may be heated at a second heating temperature that brings the temperature of the member to a temperature lower than the softening point, thereby activating the getter.

[0009] The member may be formed of a material having a softening point and a glass transition point, and the second heating temperature may be a temperature that heats the member to a temperature higher than the glass transition point and lower than the softening point.

[0010] In the second step, prior to the heating that deforms the member, the vacuum device may be heated at a heating temperature that is lower than the heating temperature during the heating in the vacuum heating furnace to degas the chamber.

[0011] The through hole may be configured to include a first portion arranged on the exterior side of the housing, and a second portion located on the room side of the housing, communicating with the first portion, and smaller than the first portion when viewed from the central axial direction of the first portion, and the inner wall of the first portion may be tapered.

[0012] The vacuum device may be a pressure sensor that detects a differential pressure between the air pressure in the vacuum chamber and the air pressure of the object to be measured.

[0013] A vacuum device according to a second aspect of the present invention is a vacuum device before a vacuum chamber is formed, and comprises a housing having a room inside which becomes the vacuum chamber, the housing having a through hole connecting the room with the outside of the housing, and a member that is disposed in the through hole, has a communicating passage connecting the room with the outside of the housing, and is formed so as to deform under its own weight when heated and seal the through hole. Effect of the Invention

[0014] According to the present invention, a vacuum chamber can be easily formed. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a flow diagram of a method for manufacturing a vacuum device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the vacuum apparatus before the vacuum chamber is formed. [Diagram 3] FIG. 3 is a schematic diagram showing a state in which a vacuum chamber is formed by heating the vacuum device in a vacuum heating furnace. [Figure 4] The upper graph in Figure 4 is a graph showing the temperature of the vacuum device over time when the vacuum device is heated in the vacuum heating furnace, and the lower graph is a graph showing the air pressure inside the vacuum heating furnace over time when the vacuum heating furnace is evacuated. [Diagram 5] 2A and 2B are an enlarged elevation view and an enlarged sectional view of the vacuum device and a heater, showing a through hole of the vacuum device in FIG. 1, a cylindrical member disposed in the through hole, and a heater for heating the vacuum device. [Figure 6]6 is an enlarged cross-sectional view of the vacuum device and the heater, showing a state after the cylindrical member in FIG. 5 has been deformed and changed into a sealing portion that seals the through hole. FIG. [Figure 7] 13A and 13B are an enlarged elevation view and an enlarged cross-sectional view of a vacuum device and a heater, showing a through hole of a vacuum device according to a modified example, a cylindrical member disposed in the through hole, and a heater for heating the vacuum device. [Figure 8] 8 is an enlarged cross-sectional view of the vacuum device and the heater, showing a state after the cylindrical member in FIG. 7 has been deformed and changed into a sealing portion that seals the through hole. FIG. [Figure 9] 13 is an enlarged cross-sectional view of the vacuum device and the heater, showing a state after the cylindrical member has been deformed into a sealing portion that seals the through hole according to the modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A method for manufacturing a vacuum device according to an embodiment of the present invention will be described below with reference to the drawings. The vacuum device manufactured in this embodiment is a pressure sensor for a diaphragm vacuum gauge that measures the degree of vacuum (atmospheric pressure) in a vacuum chamber of a semiconductor manufacturing device or the like.

[0017] As shown in FIG. 1, a manufacturing method for a vacuum device according to an embodiment of the present invention includes step S11 of forming a vacuum device 10 (see FIG. 2) before a vacuum chamber is formed, and step S12 of forming a vacuum chamber by placing the vacuum device 10 in a vacuum heating furnace 101 (see FIG. 3), evacuating the gas in the vacuum heating furnace 101, and heating the vacuum device 10 in the vacuum heating furnace 101.

[0018] 2, the vacuum device 10 formed in step S11 is a housing 20 having a room R3 therein, which serves as a vacuum chamber, and includes a through hole 22A that connects the room R3 to the outside of the housing 20. The vacuum device 10 further includes a cylindrical member 70 (see also FIG. 5) that is disposed in the through hole 22A and has a communication passage 71 that connects the room R3 to the outside of the housing 20. Details of the vacuum device 10 configured as above will be described below.

[0019] As shown in FIG. 2, the vacuum device 10 includes a housing 20, a baffle 30, a sensor element support portion 40, a sensor element 50, a getter 60, and a cylindrical member 70.

[0020] The housing 20 includes a first housing member 21, a second housing member 22, and a third housing member 23, and houses the above-mentioned members 30 to 60. Inside the housing 20, there are formed a communication passage R1 that communicates with the inside of the vacuum chamber of the semiconductor measuring device, which is a space outside the housing 20 having the atmospheric pressure of the measurement target, a communication space R2 that communicates with the communication passage R1 and has the same atmospheric pressure as the atmospheric pressure inside the vacuum chamber, and a room R3 that serves as a vacuum chamber filled with a vacuum pressure to be compared with the atmospheric pressure of the communication space R2 in step S12.

[0021] The first housing member 21 of the housing 20 has a funnel shape that defines a communication passage R1 and a communication space R2. A cylindrical second housing member 22 is joined to the first housing member 21 by welding or the like, sandwiching the peripheral portion of a disk-shaped metal thin plate 41 (described later) of the sensor element support portion 40. A disk-shaped third housing member 23 is joined to the second housing member 22 by welding or the like. The third housing member 23, together with the second housing member 22, defines a room R3 that serves as a vacuum chamber.

[0022] The third housing member 23 includes a disk-shaped main body 23A, an electrode 23C that passes through a through hole 23B formed in the main body 23A and is connected to the sensor element 50, and a hermetic seal 23D that seals the through hole 23B through which the electrode 23C passes. The electrode 23C transmits an electric signal of a differential pressure (described later) detected by the sensor element 50 to the outside of the housing 20. The electrode 23C includes a lead pin 23CA, a cylindrical metallic shield 23CB through which the lead pin 23CA passes, and a hermetic seal 23CC that seals between the lead pin 23CA and the shield 23CB. The number of electrodes is arbitrary, and a plurality of electrodes are usually provided.

[0023] The second housing member 22 is provided with a through hole 22A that penetrates in the radial direction and communicates the room R3 with the outside of the housing 20 (i.e., the space on the radially outer side). The through hole 22A has a cylindrical large diameter portion 22B on the radial outer periphery side of the second housing member 22, i.e., the outer side of the housing 20, and has a cylindrical small diameter portion 22C with a smaller diameter than the large diameter portion 22B on the inner periphery side, i.e., the room R3 side. The large diameter portion 22B and the small diameter portion 22C communicate with each other. The central axes of the large diameter portion 22B and the small diameter portion 22C are located on the same axis. That is, when viewed from the central axis direction of the large diameter portion 22B, the small diameter portion 22C is located in the center of the large diameter portion 22B. A cylindrical member 70 is fitted into the large diameter portion 22B.

[0024] The housing 20 includes a metal housing body 20S and various components attached to the housing body, such as an electrode 23C and a hermetic seal 23D. The housing body 20S in this embodiment includes, for example, a first housing member 21, a second housing member 22, and a main body 23A of a third housing member 23.

[0025] The baffle 30 is fixed to the first housing member 21 by a fixing member (not shown) or the like, and changes the flow of gas flowing from the vacuum chamber through the communication passage R1 into the upper communication space R2 toward the outer periphery of the housing 20.

[0026] The sensor element support part 40 supports the sensor element 50. The sensor element support part 40 includes a disk-shaped thin metal plate 41 and a base 42 to which the sensor element 50 is fixed. As described above, the thin metal plate 41 has its peripheral portion joined to the first housing member 21 and the second housing member 22, and is supported by the housing 20. The base 42 includes a first circular plate 42A and a second circular plate 42B. The first circular plate 42A and the second circular plate 42B are fastened to each other by bolts, nuts, etc., with the thin metal plate 41 sandwiched between them from above and below. In this way, the base 42 is fixed to the thin metal plate 41.

[0027] The sensor element support portion 40 defines the communication space R2 together with the first housing member 21. A through hole 40A is formed in the center of the sensor element support portion 40, which passes through the base 42 and the thin metal plate 41 in the vertical direction and guides the air pressure in the communication space R2 to the sensor element 50.

[0028] The sensor element 50 is fixed in close contact with the base 42 so as to cover the through hole 40A. The sensor element 50, together with the sensor element support part 40, the second housing member 22, and the third housing member 23, defines a room R3. The sensor element 50 detects the pressure difference between the air pressure in the room R3 and the air pressure in the communication space R2 introduced via the through hole 40A, i.e., the air pressure in the vacuum chamber (the object of measurement of the vacuum device 10), for example, by a change in capacitance. The sensor element 50 may be a sensor element of any type, for example, a sensor element using a piezoelectric element.

[0029] The getter 60 is activated by being heated, and adsorbs residual gas remaining in the room R3 when the room R3 is made into a vacuum chamber. This adsorption improves the degree of vacuum in the room R3. An example of such a getter 60 is a non-evaporable getter. Although not shown, the getter 60 is fixed to the surface of the main body 23A of the third housing member 23 facing the room R3 with an adhesive or the like, or is fixed to the lower surface by a fixing member attached by bolts, welding, or the like. The getter 60 may be fixed directly to the main body 23A with bolts or the like.

[0030] The cylindrical member 70 is fitted into the large diameter portion 22B of the through hole 22A of the second housing member 22. The cylindrical member 70 is cylindrical and is disposed in the through hole 22A as described above (see FIG. 2 and FIG. 5). The hollow portion of the cylindrical member 70 forms a communication passage 71 that communicates the room R3 with the outside of the housing 20. The communication passage 71 is cylindrical and disposed so that its central axis coincides with the central axis of the large diameter portion 22B. The communication passage 71 communicates with the small diameter portion 22C of the through hole 22A, thereby communicating the room R3 with the outside of the housing 20. The cylindrical member 70 is a molded body formed by compression molding glass powder, and is configured to be softened by heating in step S12. Here, the cylindrical member 70 is made of glass using glass powder, but may be made of synthetic resin using synthetic resin powder. The cylindrical member 70 does not have to be formed of powder.

[0031] In step S11 shown in FIG. 1, for example, the third housing member 23 is formed, and the getter 60 is attached to the formed third housing member 23. On the other hand, the peripheral portion of the sensor element support portion 40 (metal thin plate 41) is sandwiched between the second housing member 22 and the first housing member 21 to which the baffle 30 is attached, and these are welded and joined to form a unit. Thereafter, the third housing member 23 is joined by welding or the like to the unit formed in step S11 while the sensor element 50 is placed thereon. The sensor element 50 is fixed to the sensor element support portion 40 in a state in which it is electrically connected to the electrode 23C of the third housing member 23. Furthermore, in step S11, the cylindrical member 70 is fitted into the large diameter portion 22B of the through hole 22A of the second housing member 22 at an appropriate timing.

[0032] The vacuum device 10 is heated in step S12 as described above. The vacuum device 10 is made of a material that will not be adversely affected by this heating. This will be explained after step S12.

[0033] In step S12, as shown in the schematic diagram of Fig. 3, the vacuum device 10 formed in step S11 is placed in a vacuum heating furnace 101. The vacuum device 10 is placed such that the central axis of the through hole 22A of the housing 20 is oriented along the vertical direction (top-bottom direction). A heater 102 is placed in the vacuum heating furnace 101, in contact with the housing 20 of the vacuum device 10. Gas in the vacuum heating furnace 101 is exhausted by a vacuum pump 103.

[0034] The heater 102 generates heat by current from a heater power supply (not shown) and heats the vacuum device 10. The temperature of the heater 102 (heater temperature) is controlled by controlling the amount of current flowing through the heater 102. Although the internal structure is omitted in FIG. 3, the heater 102 is, for example, a band heater formed into a cylindrical shape with a sheath heater or the like embedded therein. The heater 102 contacts the side surface of the housing 20 of the vacuum device 10 and heats the housing 20, thereby heating the vacuum device 10. The heater 102 has an exposure hole 102A that exposes the cylindrical member 70. The heater 102 may be configured to generate heat by, for example, electromagnetic induction. The heater 102 may further have a portion that contacts the third housing member 23 of the housing 20 in order to efficiently heat the getter 60.

[0035] In step S12, the vacuum device 10 is heated by the heater 102 while the gas in the vacuum heating furnace 101 is exhausted by the vacuum pump 103. This exhaust and heating process will be described with reference to FIG. 4. It is assumed that the inside of the vacuum heating furnace 101 is initially filled with a gas such as air or an inert gas (e.g., nitrogen gas). Furthermore, unless otherwise specified, each temperature of the vacuum device 10 described below is the temperature of the housing 20 (particularly the housing main body 20S which is the majority of the housing 20) of the vacuum device 10, and can also be said to be the temperature of the cylindrical member 70 to which the heat of the housing 20 is transmitted. The temperature is detected by a temperature sensor or the like (not shown). The heating temperature of the heater 102 which is the heat generation temperature of the vacuum device 10 is also called the heater temperature.

[0036] In step S12, first, the temperature of the heater 102 is increased to heat the vacuum device 10 to temperature A (period T0 - T2), and at the same time, the inside of the vacuum heating furnace 101 is evacuated to reduce the air pressure in the vacuum heating furnace 101 to a high vacuum on the order of 1.00*10 -4 Pa (period T0 - T1). Here, before the temperature of the vacuum device 10 reaches temperature A, the air pressure is reduced to a high vacuum on the order of 1.00*10 -4 Pa (time T1 < T2). This high vacuum is maintained until the middle of the subsequent cooling (time T8) (for example, the vacuum pump 103 remains in operation). Thereby, even if gases such as impurities are generated by heating when forming the vacuum chamber as described later, the degree of vacuum in the room R3 can be maintained. When the gas in the vacuum heating furnace 101 is exhausted, the gas in the room R3 of the vacuum device 10 is also exhausted through the communication passage 71 of the cylindrical member 70. Therefore, when the inside of the vacuum heating furnace 101 is in a high vacuum, the room R3 is also in a high vacuum.

[0037] When the temperature of the vacuum device 10 reaches temperature A, the temperature A is maintained for the first predetermined period (period T2 - T3). This maintenance of temperature A is carried out in a high vacuum. Thereby, degassing is performed in which the impurities adhering to the inner wall surface in the room R3 and the getter 60 etc. are gasified and exhausted. Temperature A is a temperature lower than the glass transition point of the cylindrical member 70. For this reason, when the temperature of the vacuum device 10 is temperature A, the cylindrical member 70 remains in a hardened state.

[0038] After the above degassing, the temperature of the heater 102 is increased to heat the vacuum device 10 to temperature C in a high vacuum (period T3 - T4), and the temperature C is maintained for the second predetermined period (period T4 - T5). Temperature C is higher than the softening point of the cylindrical member 70 and is a temperature suitable for firing the cylindrical member 70. By such heating, the cylindrical member 70 shown enlarged in FIG. 5 softens in each powder and as a whole, deforms due to its own weight, and is fired to change into the sealing portion 70H shown in FIG. 6. This sealing portion 70H formed by the deformation of the cylindrical member 70 has a shape in which the communication passage 71 of the cylindrical member 70 is blocked and seals the through hole 22A of the housing 20. Thereby, the room R3 becomes a vacuum chamber.

[0039] Then, the heater temperature of the heater 102 is lowered, and the temperature of the vacuum device 10 is gradually lowered to a temperature B that is lower than the softening point and higher than the glass transition point of the sealing portion 70H (period T5 to T6), and the shape of the sealing portion 70H is stabilized. Then, the temperature B is maintained for a third predetermined period (period T6 to T7) to activate the getter 60. This improves the degree of vacuum in the room R3 that serves as a vacuum chamber. Note that heating for activating the getter 60 is started before the third predetermined period, specifically, from the timing when the vacuum device 10 reaches a temperature required for the activation of the getter 60 during the period T3 to T6. Therefore, the length of the third predetermined period in this embodiment is set in consideration of the period during which the vacuum device 10 reaches a temperature required for the activation of the getter 60 during the period T3 to T6. As described above, in order to activate the getter 60, the vacuum device 10 is heated to a temperature higher than the glass transition point of the sealing portion 70H. As a result, when the degree of vacuum in the room R3 is improved, a part of the sealing portion 70H is drawn into the small diameter portion 22C of the through hole 22A of the housing 20 in accordance with the degree of improvement in the degree of vacuum.

[0040] Thereafter, the heater temperature is gradually lowered to cool the vacuum device 10 (period T7 to T9). During the cooling, the high vacuum state is released (time T8), and air or an inert gas is introduced into the vacuum heating furnace 101. Due to this cooling, the sealing portion 70H is also cooled and hardened to a glass state.

[0041] By carrying out the above-described series of heating steps, the vacuum apparatus 10 is completed, with the room R3 serving as a vacuum chamber.

[0042] Through the above series of heating steps, the vacuum device 10 is heated up to a maximum temperature C. The temperature B for activating the getter 60 is higher than the glass transition point of the cylindrical member 70. For this reason, the following relationship of temperatures is preferable. In other words, the following relationship of temperatures is preferable: glass transition point of the cylindrical member 70<temperature B for activating the getter 60<temperature C for deforming the cylindrical member 70 to seal the through-hole 22A<heat-resistant temperature of the vacuum device 10 formed in step S11, i.e., the vacuum device 10 before the vacuum chamber is formed. The heat-resistant temperature of the vacuum device 10 is the temperature at which the vacuum device 10 will not break down or deform.

[0043] In order to satisfy the above-mentioned size relationship, for example, the housing body 20S, which is the metal part of the housing 20, is made of a nickel-chromium-iron alloy (e.g., Inconel 600), and the cylindrical member 70 is made of bismuth-based lead-free glass. Furthermore, it is preferable to form the hermetic seal 23D and the like from Kovar glass, and the sensor element support part 40 and the sensor element 50 from sapphire or the like. In such a case, the glass transition point of the cylindrical member 70 is 350°C, the glass softening point is 410°C, and the recommended firing temperature is 460°C. Therefore, the temperature A is set to 250°C, the temperature B is set to 370°C, and the temperature C is set to 410 to 460°C. Moreover, the materials of each member are arbitrary and are not limited to those mentioned above.

[0044] As described above, in this embodiment, the vacuum device 10 before forming the vacuum chamber is formed by step S11, which includes the housing 20 having the room R3 to be the vacuum chamber and the cylindrical member 70 arranged in the through hole 22A of the housing 20. Furthermore, in step S12, the gas in the room R3 is exhausted from the room R3 by exhausting the gas in the vacuum heating furnace 101 that houses the vacuum device 10. In addition, the vacuum device 10 is heated in the vacuum heating furnace 101 to heat and soften the cylindrical member 70. The softened cylindrical member 70 deforms under its own weight to become a sealing portion 70H, which seals the through hole 22A of the housing 20 of the vacuum device 10. As a result, the room R3 becomes a vacuum chamber. Therefore, in this embodiment, the cylindrical member 70 is not deformed by applying a mechanical force to the cylindrical member 70, and the vacuum chamber is formed by sealing the through hole 22A only by heating, so that the vacuum chamber is easily formed.

[0045] Furthermore, in step S12, after the cylindrical member 70 is deformed to seal the through hole 22A of the housing 20, that is, even after the sealing portion 70H is formed, the vacuum device 10 is heated in the vacuum heating furnace 101 to activate the getter 60. This allows the formation of a vacuum chamber and the activation of the getter 60 to be performed in a series of steps in the vacuum heating furnace 101, and the degree of vacuum in the vacuum chamber can be easily improved. In particular, in the past, three steps of evacuation, welding, and heating the getter were performed separately to form a vacuum chamber, but in this embodiment, the steps up to the activation of the getter 60 can be performed in a series of steps in the vacuum heating furnace 101, and a vacuum chamber, particularly a vacuum chamber whose degree of vacuum is improved by the getter 60, can be easily formed.

[0046] Furthermore, in step S12, the vacuum device 10 is heated at a first heater temperature (first heating temperature) to raise the temperature of the vacuum device 10 or the cylindrical member 70 to temperature C, and the cylindrical member 70 is deformed to form the sealing portion H. Thereafter, the heater temperature is lowered, and the vacuum device 10 is heated at a second heater temperature (second heating temperature) at which the temperature of the cylindrical member 70 is lower than the softening point, to activate the getter 60. This makes it possible to activate the getter 60 while stabilizing the shape of the sealing portion 70H. Therefore, compared to activating the getter 60 by heating the vacuum device 10 at the first heater temperature, the inconvenience of the cylindrical member 70 being unstable in shape, a part of it dripping into the small diameter portion 22C of the through hole 22A, and then flowing into the room R3 is suppressed.

[0047] Furthermore, the second heater temperature is a temperature that heats the cylindrical member 70 (sealing portion 70H) to temperature B that is higher than the glass transition point and lower than the softening point, so that the sealing portion 70H can be maintained in a rubber state for a certain period of time after the sealing portion 70H is formed. This prevents the sealing portion 70H from being cracked due to a sudden cooling. Also, for example, even if the degree of vacuum in the room R3 increases due to the activation of the getter 60 and the air pressure drops, the sealing portion 70H can be deformed by a part of the sealing portion 70H being drawn into the small diameter portion 22C in response to the drop in air pressure. This allows the sealing portion 70H to harden in a shape that corresponds to the air pressure of the room R3 that serves as a vacuum chamber when the vacuum device 10 is subsequently cooled. This prevents the sealing portion 70H from being subjected to a load (suction force that sucks the sealing portion 70H into the room R3) due to the air pressure difference in the room R3 before and after the activation of the getter 60 after the sealing portion 70H is hardened.

[0048] Furthermore, in step S12, before the heating for deforming the cylindrical member 70 by raising the vacuum device 10 to temperature C, the vacuum device 10 is heated to temperature A in the vacuum heating furnace at a third heater temperature (third heating temperature) lower than the first heater temperature (first heating temperature) during the heating, thereby degassing the inside of the room R3. This allows the processes from degassing to activation of the getter 60 to be performed in a series of steps in the vacuum heating furnace 101.

[0049] Furthermore, in the vacuum apparatus 10 before the formation of the vacuum chamber formed in step S11, a cylindrical member 70 having a communication passage 71 and formed so as to be deformed by its own weight when heated to seal the through hole 22A of the housing 20 having the room R3 therein, is provided. As a result, the vacuum chamber is formed by drawing a vacuum inside the vacuum heating furnace 101 and heating and deforming the cylindrical member 70 inside the vacuum heating furnace 101, so that the vacuum chamber is easily formed.

[0050] In the above embodiment, a series of heating processes and the like can be performed in the vacuum heating furnace 101. Therefore, the plurality of vacuum devices 10 formed in step S11 may be placed in the vacuum heating furnace 101, and the above heating processes and the like may be performed on the plurality of vacuum devices 10 at once, to form a vacuum chamber for each vacuum device 10. This allows the formation of a vacuum chamber for each of the plurality of vacuum devices 10 to be easily performed at once.

[0051] The above embodiment may be modified in various ways. For example, the shape of the vacuum device 10 may be changed as appropriate. For example, the housing 20 is cylindrical in the above embodiment, but may be polygonal. The shape of the through hole 22A of the housing 20 may also be arbitrary. The through hole 22A may not be cylindrical, but may be polygonal. The cylindrical member 70 may also be polygonal in shape depending on the shape of the through hole 22A. Each process of step S12 may be performed manually, or may be performed by controlling the heater 102 and the vacuum pump 103 by a controller (not shown).

[0052] In step S12, the vacuum device 10 may be placed in the vacuum heating furnace 101 with the central axis of the through hole 22A oriented horizontally. Even in this case, the heated cylindrical member 70 deforms under its own weight to block the communication passage 71, and as a result, the cylindrical member 70 can be deformed into the sealing portion 70H that seals the through hole 22A. In this case, the heater temperature for activating the getter 60 may be set to temperature B, which is higher than the glass transition point of the cylindrical member 70 (sealing portion 70H), as described above. This allows the sealing portion 70H to be in a rubber state during heating to temperature B of the vacuum device 10 or the cylindrical member 70, and the shape of the sealing portion 70H can be maintained, and most of the softened sealing portion 70H is prevented from flowing down from the through hole 22A.

[0053] The through hole 22A of the second housing member 22 of the housing 20 and the cylindrical member 70 may be changed to a through hole 222A and a notch member 270 as shown in FIG. 7. The through hole 222A has a large diameter portion 222B and a small diameter portion 222C corresponding to the large diameter portion 22B and the small diameter portion 22C of the through hole 22A, respectively. The small diameter portion 222C is arranged so as to communicate with the lower portion of the large diameter portion 222B (the lower portion when the top-to-bottom direction when the central axes of the large diameter portion 222B and the small diameter portion 222C are oriented along the horizontal direction is taken as the up-down direction). The notch member 270 has a communication passage 271 corresponding to the communication passage 71 of the cylindrical member 70. The communication passage 271 communicates with the small diameter portion 222C and is constituted by a notch hole provided in the lower portion of the notch member 270. In such a case, when the vacuum device 10 is heated in step S12, the large diameter portion 222B and the small diameter portion 222C may be placed in the vacuum heating furnace 101 with the central axes of the large diameter portion 222B and the small diameter portion 222C oriented horizontally. In such a case, the heated cutout member 270 is deformed by its own weight, as shown in FIG. 8, to block the communication passage 271, and as a result, it can be deformed into the sealing portion 270H that seals the through hole 222A. Here, in particular, the communication passage 271 can be easily crushed by the deformation of the cutout member 270 by its own weight, and the small diameter portion 222C located at the lower part of the through hole 222A can be easily sealed. As such, the member placed in the through hole 22A or the like of the housing 20 in the above embodiment and modified example may be a member having the communication passage 71 or the like.

[0054] The through holes such as the through holes 22A and 222A, which communicate between the room R3 and the outside of the housing 20 of the vacuum device 10, may include a first portion (large diameter portion 22B in the above) arranged on the outside of the housing 20, and a second portion (small diameter portion 22C in the above) located on the room R3 side, communicating with the first portion, and smaller than the first portion as viewed from the central axis direction of the first portion. This allows a member having a communication path such as a cylindrical member 70 to be arranged in the first portion, and when the member is deformed, the second portion can be easily blocked. Therefore, the member after deformation, that is, the sealing portion, can easily seal the through hole. Furthermore, a taper may be provided on the inner wall of the first portion, specifically, on the inner side or bottom surface. For example, as shown in FIG. 9, the bottom surface 22BA on which the opening of the small diameter portion 22C is formed in the large diameter portion 22B may be formed into a side shape of a truncated cone, and the bottom surface BA may be tapered. Such a taper can increase the bonding area between sealing portion 70H and the inner wall of through hole 22A, thereby obtaining good bonding strength of sealing portion 70H to housing 20. Note that the outer surface of tubular member 70 before becoming sealing portion 70H may also be tapered to match bottom surface BA.

[0055] In step S12, when the member to be the sealing part, such as the cylindrical member 70 or the notched member 270, is heated and deformed, the member may be directly heated. When the member to be the sealing part, such as the cylindrical member 70, has a melting point, the softening may be a melting of the member exceeding the melting point.

[0056] The present invention can be generally applied to a vacuum device having a housing with a vacuum chamber inside and a manufacturing method thereof. For example, the present invention can be applied to a vacuum device formed as a pressure sensor that detects the differential pressure between the atmospheric pressure of the vacuum chamber and the atmospheric pressure of the measurement target, as well as to various vacuum devices and manufacturing methods thereof, such as semiconductor manufacturing equipment having a vacuum chamber, lamps, electron tubes, vacuum insulation materials, and MEMS (Micro Electro Mechanical Systems). The pressure sensor may be a sensor filled with a liquid such as silicone oil that transmits the atmospheric pressure of the measurement target.

[0057] Although the present invention has been described above with reference to the embodiment and the modified examples, the present invention is not limited to the above embodiment and the modified examples. For example, the present invention includes various modifications to the above embodiment and the modified examples that can be understood by a person skilled in the art within the scope of the technical idea of ​​the present invention. The configurations listed in the above embodiment and the modified examples can be appropriately combined within a range without contradiction. [Explanation of symbols]

[0058] Reference Signs List 10...vacuum device, 20...housing, 21...first housing member, 22...second housing member, 22A...through hole, 22B...large diameter portion, 22BA...bottom surface, 22C...small diameter portion, 23...third housing member, 23A...main body, 23B...through hole, 23C...electrode, 23D...hermetic seal, 30...baffle, 40...sensor element support portion, 40A...through hole, 50...sensor element, 60...getter, 70...cylindrical member, 71...communicating passage, 222A...through hole, 222B...large diameter portion, 222C...small diameter portion, 270...notched member, 271...communicating passage, R1...communicating passage, R2...communicating space, R3...room.

Claims

1. a first step of forming a vacuum device before forming a vacuum chamber, the vacuum device comprising: a housing having a chamber therein that serves as a vacuum chamber, the housing having a through hole that connects the chamber to the outside of the housing; a member that is disposed in the through hole and has a communication passage that connects the chamber to the outside of the housing; and a getter that is disposed in the chamber and is activated by heating; a second step of evacuating gas from a vacuum heating furnace containing the vacuum device to evacuate the gas from the room through the communicating passage, heating the vacuum device at a first heating temperature in the vacuum heating furnace to soften the member and deform the member under its own weight to seal the through hole, and then lowering the heating temperature of the vacuum device from the first heating temperature to a second heating temperature to heat the vacuum device in the vacuum heating furnace even after sealing the through hole and activate the getter, thereby forming the vacuum chamber; The member has a softening point and a glass transition point, the first heating temperature is a heating temperature that increases the temperature of the member above the softening point, The second heating temperature is a heating temperature that makes the temperature of the member higher than the glass transition point and lower than the softening point. A method for manufacturing a vacuum device.

2. The through hole comprises a first portion disposed on the exterior side of the housing and in which the member is disposed, and a second portion located on the room side of the housing, communicating with the first portion, and being smaller than the first portion when viewed from the central axial direction of the first portion; In the second step, the getter is activated by heating at the second heating temperature to improve the degree of vacuum in the chamber, and a part of the member that has undergone glass transition is drawn into the second part. A method for manufacturing the vacuum device according to claim 1 .

3. In the second step, the member is heated to a temperature higher than the glass transition point and lower than the softening point by heating at the second heating temperature, thereby maintaining the member in a rubbery state for a certain period of time. A method for manufacturing a vacuum device according to claim 1 or 2.

4. The member is a bismuth-based lead-free glass. The method for manufacturing a vacuum device according to any one of claims 1 to 3.

5. In the second step, before the heating for deforming the member, the vacuum device is heated at a heating temperature lower than the heating temperature during the heating in the vacuum heating furnace to degas the chamber. A method for manufacturing a vacuum device according to any one of claims 1 to 4.

6. The vacuum device is a pressure sensor that detects a differential pressure between the air pressure in the vacuum chamber and the air pressure of the object to be measured. A method for manufacturing a vacuum device according to any one of claims 1 to 5.

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