JP7628840B2 - Vacuum device manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a vacuum device having a vacuum chamber, and to a vacuum device.

The vacuum chamber of the vacuum device is formed, for example, by a method such as that disclosed in Patent Document 1. First, a vacuum is drawn through a pipe (vacuum drawing pipe 9) that communicates with a room that will become the vacuum chamber (reference pressure chamber 7). 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.

Japanese Unexamined Patent Publication No. 63-133032

In the conventional method of forming a vacuum chamber disclosed in Patent Document 1, it is necessary to physically deform the pipe after drawing a vacuum to seal it. Therefore, forming the vacuum chamber is time-consuming.

The objective of the present invention is to make it possible to easily form a vacuum chamber.

In order to solve the above problem, the manufacturing method of a vacuum device according to the first aspect of the present invention includes a first step of forming a vacuum device before forming a vacuum chamber, the vacuum device including 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, and 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 second step of evacuating gas from a vacuum heating furnace that houses the vacuum device to evacuate the gas from the chamber through the communication passage, 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.

The vacuum device formed in the first step may include a getter in the chamber that is activated by heating, 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.

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.

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.

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

The through hole may be configured to include a first portion disposed 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 as viewed in the direction of the central axis of the first portion, and the inner wall of the first portion may be tapered.

The vacuum device may be a pressure sensor that detects the pressure difference between the air pressure in the vacuum chamber and the air pressure to be measured.

The vacuum device according to the second aspect of the present invention is a vacuum device before a vacuum chamber is formed, and is a housing having a room inside that will become the vacuum chamber, the housing having a through hole that connects the room to the outside of the housing, and a member that is disposed in the through hole, has a communication passage that connects the room to the outside of the housing, and is formed so that it deforms under its own weight when heated to seal the through hole.

The present invention makes it easy to form a vacuum chamber.

FIG. 1 is a flow chart of a method for manufacturing a vacuum device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the vacuum apparatus before the vacuum chamber is formed. 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. 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. 2A and 2B are an enlarged elevational 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. 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. 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. 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. 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.

The manufacturing method of a vacuum device according to 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.

As shown in FIG. 1, the method for manufacturing 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 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 to form a vacuum chamber.

The vacuum device 10 formed in step S11 is a housing 20 having a room R3 therein, which serves as a vacuum chamber, as shown in FIG. 2, and includes a housing 20 having 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 in this way are described below.

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

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 that has the air pressure of the measurement target, a communication space R2 that communicates with the communication passage R1 and has the same air pressure as the air pressure inside the vacuum chamber, and a room R3 that serves as a vacuum chamber filled with a vacuum air pressure that is compared with the air pressure in the communication space R2 in step S12.

The first housing member 21 of the housing 20 has a funnel shape that defines the communication passage R1 and the 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 sheet 41 (described below) 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.

The third housing member 23 comprises 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 electrical signal of the differential pressure detected by the sensor element 50 (described below) to the outside of the housing 20. The electrode 23C comprises 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 typically multiple electrodes are provided.

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 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 are in communication. The central axes of the large diameter portion 22B and the small diameter portion 22C are located on the same axis. In other words, 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.

The housing 20 is composed of a metal housing body 20S and various parts attached to the housing body, such as an electrode 23C and a hermetic seal 23D. In this embodiment, the housing body 20S is composed of, for example, a first housing member 21, a second housing member 22, and a body 23A of a third housing member 23.

The baffle 30 is fixed to the first housing member 21 by a fixing member (not shown) or the like, and redirects 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.

The sensor element support part 40 supports the sensor element 50. The sensor element support part 40 comprises 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 comprises a first circular plate 42A and a second circular plate 42B. The first circular plate 42A and the second circular plate 42B are fastened 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.

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

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 40, the second housing member 22, and the third housing member 23, defines the 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 that uses a piezoelectric element.

The getter 60 is activated by heating, and adsorbs residual gas remaining in the chamber R3 when the chamber R3 is made into a vacuum chamber. This adsorption improves the degree of vacuum in the chamber 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 chamber R3 with adhesive or the like, or is fixed to the underside of the main body 23A with a fixing member attached by bolts or welding or the like. The getter 60 may also be fixed directly to the main body 23A with bolts or the like.

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 compressing and 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.

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 (thin metal 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. After that, 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. 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.

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.

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 so 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. The gas in the vacuum heating furnace 101 is exhausted by a vacuum pump 103.

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 embedded therein. The heater 102 contacts the side 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.

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). In addition, unless otherwise specified, each temperature of the vacuum device 10 described below is the temperature of the housing 20 of the vacuum device 10 (particularly the housing body 20S which is the majority of the housing 20), 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). In addition, the heating temperature of the heater 102 which heats the vacuum device 10 is also called the heater temperature.

In step S12, first, the heater temperature of the heater 102 is increased to heat the vacuum device 10 to temperature A (period T0 to T2), and the vacuum furnace 101 is evacuated to reduce the air pressure in the vacuum furnace 101 to a high vacuum of the order of 1.00*10 ⁻⁴ Pa (period T0 to T1). Here, the air pressure is reduced to a high vacuum of the order of 1.00*10 ⁻⁴ Pa before the temperature of the vacuum device 10 reaches temperature A (time T1<T2). This high vacuum is maintained until the middle of the cooling process (time T8) described later (for example, the vacuum pump 103 is kept operating). This makes it possible to maintain the degree of vacuum in the room R3 even if gas such as impurities is generated by heating when forming a vacuum chamber as described later. The gas in the room R3 of the vacuum device 10 is also evacuated through the communication passage 71 of the cylindrical member 70 by evacuating the gas in the vacuum furnace 101. Therefore, when the inside of the vacuum heating furnace 101 is at a high vacuum, the room R3 is also at a high vacuum.

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

After the degassing, the heater temperature of the heater 102 is increased to heat the vacuum device 10 to temperature C in a high vacuum (period T3 to T4), and the temperature C is maintained for a second predetermined period (period T4 to 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 in an enlarged view in FIG. 5 softens in each powder and as a whole, deforms under its own weight, is fired, and changes into the sealing portion 70H shown in FIG. 6. The 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. As a result, the room R3 becomes a vacuum chamber.

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 below the softening point and above the glass transition point of the sealing portion 70H (period T5 to T6), stabilizing the shape of the sealing portion 70H. Then, the temperature B is maintained for a third predetermined period (period T6 to T7) to activate the getter 60. This improves the vacuum level of the chamber R3, which is 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 the 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 taking into consideration the period during which the vacuum device 10 reaches the 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 above the glass transition point of the sealing portion 70H. As a result, when the degree of vacuum in the room R3 is improved, a portion of the sealing portion 70H is drawn into the small diameter portion 22C of the through hole 22A of the housing 20 depending on the degree of improvement in the degree of vacuum.

Then, the heater temperature is gradually lowered to cool the vacuum device 10 (period T7 to T9). During this cooling, the high vacuum state is released (time T8), and air or an inert gas is introduced into the vacuum heating furnace 101. This cooling also cools the sealing portion 70H, causing it to harden into a glass state.

Through this series of heating steps, the vacuum device 10 is completed, with room R3 serving as a vacuum chamber.

By the above series of heating steps, the vacuum device 10 is heated up to a maximum temperature C. Furthermore, 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 resistance temperature of the vacuum device 10 formed in step S11, i.e., the vacuum device 10 before the vacuum chamber is formed. The heat resistance temperature of the vacuum device 10 is the temperature at which the vacuum device 10 will not break down or deform.

To satisfy the above 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 advisable 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, temperature A is set to 250°C, temperature B to 370°C, and temperature C to 410 to 460°C. Furthermore, the materials of each member are arbitrary and are not limited to those mentioned above.

As described above, in this embodiment, in step S11, the vacuum device 10 before the formation of the vacuum chamber is formed, which includes the housing 20 having the chamber 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 vacuum heating furnace 101 that houses the vacuum device 10 is exhausted, thereby exhausting the gas in the chamber R3 from the chamber R3. 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 chamber R3 becomes a vacuum chamber. Therefore, in this embodiment, the vacuum chamber is formed by sealing the through hole 22A only by heating without deforming the cylindrical member 70 by applying a mechanical force, so that the vacuum chamber is easily formed.

Furthermore, in step S12, after the cylindrical member 70 is deformed to seal the through hole 22A of the housing 20, that is, 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 separate steps of evacuation, welding, and heating the getter were performed 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.

Furthermore, in step S12, the vacuum device 10 is heated at the 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. After that, the heater temperature is lowered, and the vacuum device 10 is heated at the second heater temperature (second heating temperature) at which the temperature of the cylindrical member 70 is lower than the softening point, and the getter 60 is activated. This allows the getter 60 to be activated in a state in which the shape of the sealing portion 70H is stabilized. Therefore, compared to activating the getter 60 by heating the vacuum device 10 at the first heater temperature, the inconvenience of the shape of the cylindrical member 70 being unstable, 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.

Furthermore, since the second heater temperature is a temperature that heats the cylindrical member 70 (sealing portion 70H) to a temperature B that is higher than the glass transition point and lower than the softening point, 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 cracking due to a sudden cooling. In addition, even if the vacuum level 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. As a result, the sealing portion 70H can be hardened in a shape that corresponds to the air pressure of the room R3, which is 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.

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

Furthermore, in the vacuum device 10 before the formation of the vacuum chamber formed in step S11, a cylindrical member 70 is provided in the through hole 22A of the housing 20, which has the chamber R3 inside it to become the vacuum chamber, and which has a communication passage 71 and is formed so that it deforms under its own weight when heated to seal the through hole 22A. 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.

In the above embodiment, a series of heating processes and the like can be carried out in the vacuum heating furnace 101. Therefore, the multiple vacuum devices 10 formed in step S11 can be placed in the vacuum heating furnace 101, and the above heating processes and the like can be carried out on the multiple vacuum devices 10 at once, forming a vacuum chamber for each vacuum device 10. This makes it possible to easily form a vacuum chamber for each of the multiple vacuum devices 10 at once.

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 is also arbitrary. The through hole 22A may be polygonal instead of cylindrical. The shape of the cylindrical member 70 may also be polygonal depending on the shape of the through hole 22A. Each process of step S12 may be performed manually or by controlling the heater 102 and the vacuum pump 103 with a controller (not shown).

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 may deform under its own weight, blocking the communication passage 71, and as a result, may deform 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, preventing much of the softened sealing portion 70H from flowing down from the through hole 22A.

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 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 is communicated 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 may be deformed by its own weight to block the communication passage 271, as shown in FIG. 8, and as a result, the cutout member 270 may be deformed into a sealing portion 270H that seals the through hole 222A. In particular, the deformation of the cutout member 270 by its own weight can easily crush the communication passage 271, and the small diameter portion 222C located at the bottom of the through hole 222A can be easily sealed. In this way, the member placed in the through hole 22A of the housing 20 in the above embodiment and modified example may be a member having a communication passage 71, etc.

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 have a first portion (large diameter portion 22B in the above) located on the outside of the housing 20, and a second portion (small diameter portion 22C in the above) located on the room R3 side, which communicates with the first portion and is smaller than the first portion when 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 placed 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 side inner surface 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, so that the bottom surface BA is tapered. This taper increases the bonding area between the sealing portion 70H and the inner wall of the through hole 22A, and provides good bonding strength between the sealing portion 70H and the housing 20. Note that the outer surface of the cylindrical member 70 before it becomes the sealing portion 70H may also be tapered to match the bottom surface BA.

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 caused by the member exceeding the melting point and melting.

The present invention can be generally applied to vacuum devices having a housing with a vacuum chamber inside and methods for manufacturing the same. For example, the present invention can be applied to vacuum devices formed as pressure sensors that detect the pressure difference between the air pressure in the vacuum chamber and the air pressure of the object to be measured, as well as to various vacuum devices and methods for manufacturing the same, 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 air pressure of the object to be measured.

Although the present invention has been described above with reference to the embodiments and modifications, the present invention is not limited to the above-mentioned embodiments and modifications. For example, the present invention includes various modifications to the above-mentioned embodiments and modifications that can be understood by a person skilled in the art within the scope of the technical concept of the present invention. The configurations listed in the above-mentioned embodiments and modifications can be combined as appropriate within a range that does not cause inconsistencies.

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...communication passage, 222A...through hole, 222B...large diameter portion, 222C...small diameter portion, 270...notch member, 271...communication passage, R1...communication passage, R2...communication space, R3...room.

Claims (6)

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. the through hole includes 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 in a central axis 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 . In the second step, the member is heated at the second heating temperature to a temperature higher than the glass transition point and lower than the softening point, 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. 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. 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. 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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