JP2019149303A - Sealed terminal - Google Patents

Abstract

To provide a long-life sealed terminal capable of reducing stress generated between an electrical insulator and a metal part even under an environment having a large temperature difference, such as under a cryogenic environment.SOLUTION: A sealed terminal of the present disclosure includes: a ceramic plate 1 including a first surface 1x and a second surface 1y and having a through hole H penetrating between the first surface and the second surface; a metal pin 2 inserted through the through hole H; and a brazing material 3 for sealing a gap between the pin 2 and the through hole H. The ceramic plate 1 includes: a first region R1 including an inner peripheral surface 1h of the through hole H and extending in the thickness direction of the ceramic plate 1, in a direction perpendicular to the thickness direction between the first surface 1x and the second surface 1y; and a second region R2 adjacent to the first region R1. In a cross-section view along the penetration direction of the through hole H, the thickness (d1) of the ceramic plate in the first region R1 is thicker than the thickness (d2) of the ceramic plate in the second region R2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sealed terminal used for electrical connection with the outside at a position where gas or liquid is sealed.

  In an electrical apparatus such as a semiconductor manufacturing apparatus that is used by blocking the internal atmosphere and the external atmosphere, a sealed terminal is attached to transmit and receive an electrical signal between the inside and the outside. The sealed terminal is for conducting an electrical or electrical signal while preventing the flow of fluid such as gas and liquid, and the one for preventing the passage of gas is the hermetic terminal, and the one for preventing the passage of liquid is the liquid-tight terminal. Sometimes called.

  As an example of such a sealed terminal (airtight terminal), in Patent Document 1 and the like, a metallized layer made of metal is formed on the entire surface of an electrical insulator made of cylindrical alumina ceramic having a through hole in the thickness direction. A circle having a metallized layer (a metal layer serving as a primer for plating) formed on the outer peripheral surface and separated from the inner peripheral surface of the through-hole by cutting it into an axial direction at predetermined intervals (so-called “ring cutting”). A plate-like electrical insulator is formed.

  Such a disc-shaped electrical insulator is inserted into a sealing hole or opening formed in a work W such as a substrate or a base of an electric device or the like, and the outer periphery in contact with the work W is Is fixed to the sealing hole by brazing or the like through the metallized layer provided on the surface.

  Further, a metal terminal such as a pin is inserted into the through hole provided inside the electrical insulator, and the terminal is connected to the inside of the through hole through the metallization layer on the inner periphery of the through hole described above. It is attached to the circumference by brazing. Thereby, the sealing terminal can maintain the inside of the workpiece W in a sealed state while conducting electricity such as signals inside and outside the workpiece W.

JP-A-2005-317230

  By the way, in the sealed terminal as described above, if the temperature rise and fall are repeated, the electrical insulator made of ceramics and the like may be damaged such as cracks and chips, and the sealing performance such as airtightness and liquid tightness may be impaired. There is. Damage to the electrical insulator, such as cracks, occurs due to stress caused by the difference in the coefficient of linear expansion (thermal expansion coefficient) between the electrical insulator and a metal part such as a lead terminal fitted in the through hole.・ It is known to make progress.

  In particular, when a sealed terminal is used in an environment where a low-temperature liquid such as liquefied natural gas (LNG), liquid hydrogen, or liquid helium is present, a greater stress is expected to occur. There is a need for sealed terminals that can be used.

  An object of the present invention is to provide a long-life sealed terminal capable of reducing stress generated between an electrical insulator and a metal part even under an environment subjected to a large temperature difference such as a cryogenic environment. It is.

The sealed terminal of the present disclosure includes a first surface and a second surface,
A ceramic plate having a through hole penetrating between the first surface and the second surface;
A metal pin inserted through the through hole;
A brazing material that seals a gap between the pin and the through-hole,
The ceramic plate is in a direction perpendicular to the thickness direction between the first surface and the second surface,
A first portion including an inner peripheral surface of the through hole and extending in a thickness direction of the ceramic plate;
A second part adjacent to the first part,
In a cross-sectional view along the penetration direction of the through hole,
The thickness of the ceramic plate in the first part is greater than the thickness of the ceramic plate in the second part.

  According to the present disclosure, the possibility of occurrence of defects such as cracks and chippings in the ceramic plate is reduced even when the temperature is raised and lowered repeatedly or exposed to an extremely low temperature environment. It is possible to provide a highly reliable and long-life sealed terminal.

(A) is a partial cross-sectional view showing a schematic configuration of the sealed terminal of the first embodiment, (b) is an enlarged cross-sectional view of a brazed joint (P part), (c) was obtained by simulation analysis, It is a figure which shows distribution of the stress vector of the ceramic board in a junction part (Q part). (A) is the fragmentary sectional view of the sealing terminal of 2nd Embodiment, (b) is the P section expanded sectional view of (a). (A) is the fragmentary sectional view of the sealing terminal of 3rd Embodiment, (b) is the P section expanded sectional view of (a).

  As shown in the schematic configuration diagram (a) in FIGS. 1 to 3, the sealed terminal in each embodiment of the present disclosure is a circular (annular) electrical insulator (having a through-hole H formed in the center) ( The main component is a ceramic plate 1) and a metal lead terminal (pin 2) inserted through the through hole H as a conductor.

The ceramic plate 1 is an insulating one made of, for example, alumina (Al ₂ O ₃ ) ceramics, and is a sealed terminal provided on a substrate or base on the electric device side (hereinafter collectively referred to as a workpiece W). The pin 2 is held while being fitted in the opening hole for mounting and maintaining electrical insulation with the workpiece W. In each figure, the illustrated vertical direction is described as the through direction of the through hole H or the thickness (thickness) direction of the ceramic plate 1.

  The illustrated ceramic plate 1 has a first surface (1x) on the upper side in the drawing, which is one main surface, and a second surface (1y) on the lower side in the drawing, which is the other main surface, The through-hole H (the inner peripheral surface 1h) for inserting the pin 2 as the lead terminal described above is formed between the two parallel surfaces. Further, a metallized layer for performing a brazing process described later is provided on the outer peripheral surface of the ceramic plate 1 and the inner peripheral surface 1h of the through hole H in the horizontal direction in the figure.

  In FIG. 1 to FIG. 3A, for convenience of explanation, each metallized layer is depicted as a layer having a thickness, but in actuality, it is much thinner than other members and layers. It is. In addition, after performing the brazing process described later, the metallized layer is buried together with the “wax” layer, so in the enlarged view of each figure (b), a hidden line (dotted line) or It is drawn as a simple thick line (solid line) with no thickness. And since the metallized layer is integrated with the above-mentioned “wax” layer, in the stress simulation described later, this metallized layer is incorporated as a part of the thickness of the “wax”. It is not involved in the analysis as a single layer.

  The pin 2 is made of a metal having a low melting point and a low electric resistance, such as copper (Cu), silver (Ag), or a copper alloy such as brass, brass, phosphor bronze, etc., and is formed into a cylindrical or prismatic shape. Yes. In addition, when there are a plurality of through holes in the ceramic plate 1, a plurality of pins 2 are arranged according to the number of the pins 2. In addition, the pin 2 is subjected to conventionally known metal processing such as cutting processing using a lathe or press processing using a die, by cutting a bar material serving as a terminal, or a bar material serving as a terminal. Is formed into a predetermined thickness and length.

  The pin 2 has nickel (Ni), gold (Au), platinum (on the periphery (surface) of the outer peripheral surface of the ceramic plate 1 (metallized layer on the inner surface of the through hole H) and its periphery. A protective metal layer made of Pt) or the like may be applied. This protective metal layer isolates the pin 2 from the joining brazing material, and therefore can effectively prevent the pin 2 from chemically reacting with the brazing material. This protective metal layer is also incorporated in the stress simulation described later as a part of the thickness of the “wax” layer in the stress simulation described later. Not involved.

  As the brazing material 3 used to join the pins 2 and the ceramic plate 1, silver brazing (Ag), gold-copper brazing (Au—Cu), or the like is used.

A first embodiment (FIG. 1) using the above materials and configuration will be described.
FIG. 1A is a partial cross-sectional view showing a schematic configuration of the sealed terminal according to the first embodiment, and FIG. 1B is an enlarged cross-sectional view of a joint portion subjected to brazing. Moreover, FIG.1 (c) is a figure which shows distribution of the stress vector of the ceramic board in a junction part obtained by simulation analysis.

  As shown in FIG. 1 (a), the ceramic plate 1A of the sealed terminal according to the first embodiment has through-hole forming portions each having a first surface 1x and a second surface 1y that are parallel to each other, which are called main surfaces. In addition, a through hole H for inserting the pin 2 is formed at a substantially central portion thereof.

  The inserted pin 2 has a columnar shape (in this example, a columnar shape) made of Fe—Ni—Co alloy or Cu, and its outer peripheral surface 2x is parallel to the inner peripheral surface (inner wall) 1h of the through hole H. It is the opposite surface.

  Then, as shown in FIG. 1B, the space between the pin 2 and the inner peripheral surface 1h of the through hole H is brazed using a brazing material 3, and the inner surface of the outer peripheral surface 2x of the pin 2 and the through hole H The space between the peripheral surface 1h is hermetically or liquid-tightly closed and sealed.

  In the brazing process, after the workpiece W and the ceramic plate 1 and the pin 2 are preheated in a state where the members are combined in a high-temperature environment (for example, 780 ° C.) where the brazing material 3 is melted, such as in a heating furnace, The melted brazing material 3 is carried out by soaking in the gap between the outer peripheral surface 2x of the pin 2 and the inner peripheral surface 1h of the through hole H by capillary action. And in that state, it cools until the whole sealing terminal cools to room temperature (for example, 25 degreeC), and a sealing terminal is completed.

  The structural feature of the sealed terminal of the present embodiment is that the direction perpendicular to the thickness direction between the first surface 1x and the second surface 1y of the ceramic plate 1A (that is, the first surface 1x or the second surface 1y). A ceramic plate in the first portion having a first portion (described later) including the inner peripheral surface 1h of the through-hole H and a second portion (described later) adjacent to the first portion in the planar direction). The thickness in the through direction of the through hole H of 1A is that it is formed thicker than the thickness in the through direction of the through hole H of the ceramic plate 1A in the second part.

  Specifically, when the ceramic plate 1A of the first embodiment is viewed in a cross section along the penetration direction (the vertical direction in the drawing) of the through hole H as shown in FIG. At least one surface (both surfaces in this example) of the first surface 1x and the second surface 1y of the region close to the through hole H including the inner peripheral surface 1h (hereinafter, first portion R1) approaches the through hole H. As a result, the distance between the other surface gradually increases and is formed on an inclined surface. As a result, the thickness d1 of the first portion R1 of the ceramic plate 1A is equal to another portion (hereinafter, second portion R2) adjacent to the first portion R1 where the first surface 1x and the second surface 1y are parallel to each other. It is thicker than the thickness d2 of the ceramic plate 1A (d1> d2).

  Here, FIG. 1C shows the distribution of the stress vector of the ceramic plate 1A at the joint based on the simulation analysis. The simulation shows the linear expansion of the metal and the ceramic when the ceramic plate 1A and the pin 2 are brazed in a high temperature (780 ° C.) environment and then allowed to cool to room temperature (25 ° C.) in the above configuration. The stress generated on the ceramic plate 1A side due to the difference in coefficients is analyzed using software.

  As can be seen from the vector distribution diagram of FIG. 1C, the stress vector at the end (upper side in the figure) in the thickness direction of the ceramic plate 1A is the inclined portion of the first surface 1x (the surface of the first portion R1). Therefore, even if a crack such as a crack is generated at the end or surface of the ceramic plate 1A, the crack or the like does not progress toward the inside of the ceramic plate 1A.

  Therefore, according to the above configuration, the ceramic plate 1A of the first embodiment and the sealing terminal using the ceramic plate 1B are cooled between the electrical insulator and the metal component even when subjected to a large temperature difference such as being cooled to a very low temperature. Breakage such as cracks and chips is unlikely to occur, and even if it occurs, its progress is suppressed. That is, the sealed terminal of the present embodiment can be a highly reliable and long-life sealed terminal.

  In addition, the thickness of the area | region (1st site | part R1) adjacent to the through-hole including the internal peripheral surface 1h of the through-hole H of the ceramic board in embodiment is based on the thickness of the area | region (2nd site | part R2) adjacent to this. The thick construction method can be realized by other shapes. For example, a ceramic plate 1B having a curved inclined surface as shown in FIG. 2 or a ceramic plate 1C having a stepped portion as shown in FIG. 3 may be used. Moreover, the corner | angular part of the said step part is good also as a shape which has a chamfering (C surface) shape or a rounded corner (R surface), as shown by a virtual line (two-dot chain line). Also with the above configuration, the same operations and effects as in the first embodiment can be achieved.

  In any shape, the difference between the thickness d1 of the first part R1 adjacent to the through hole H and the thickness d2 of the second part R2 adjacent thereto is preferably 0.01 mm or more. . Furthermore, it is desirable that the width of the first portion R1 adjacent to the through hole H in the direction orthogonal to the thickness d1 direction of the ceramic plate is 0.01 mm or more and 10 mm or less.

  It should be noted that the present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the scope of the present invention.

  The above-described simulation analysis of the stress generated in the ceramic plate at the joint is performed using Marc (registered trademark) manufactured by MSC Software. The stress generated in the ceramic plate when the gap between the ceramic plate (A-479SS) and the pin (made of Cu, for example) is brazed with a brazing material (BAg-8) is used with the above software. Simulated. In addition, the result (stress vector distribution diagram) shown in FIG. 1C (part Q of FIG. 1B) shows that the brazing process is performed at 780 ° C. (stress free), and it is allowed to cool at room temperature and atmospheric pressure. The temperature is lowered to room temperature (25 ° C.), and at 25 ° C., it is visually determined how much stress vector is generated in the joint (surface layer) of the ceramic plate due to the difference in linear expansion coefficient with the pin. Display.

  The hermetic terminal of the present invention can be suitably used for an electric device such as a semiconductor manufacturing apparatus that is used by blocking an internal atmosphere and an external atmosphere. It can also be used in an environment where a low-temperature liquid such as liquefied natural gas (LNG), liquid helium, liquid nitrogen, liquid oxygen, liquid neon, or liquid argon exists. Furthermore, it is also used in parts that come into contact with these cryogenic liquids in equipment such as LNG stations or hydrogen gas stations that fill vehicles with cryogenic liquids such as liquefied natural gas (LNG) or liquid hydrogen. It is possible.

DESCRIPTION OF SYMBOLS 1 Ceramic plate 1A, 1B, 1C Ceramic plate 1h Inner peripheral surface 1x 1st surface 1y 2nd surface 2 Pin 2x Outer peripheral surface 3 Brazing material H Through-hole W Workpiece | work R1 1st site | part R2 2nd site | part

Claims (5)

A ceramic plate including a first surface and a second surface, and having a through-hole penetrating between the first surface and the second surface;
A metal pin inserted through the through hole;
A brazing material that seals a gap between the pin and the through-hole,
The ceramic plate is in a direction perpendicular to the thickness direction between the first surface and the second surface,
A first portion including an inner peripheral surface of the through hole and extending in a thickness direction of the ceramic plate;
A second part adjacent to the first part,
In a cross-sectional view along the penetration direction of the through hole,
The thickness of the ceramic board in the said 1st site | part is a sealing terminal thicker than the thickness of the ceramic board in the said 2nd site | part. In a cross-sectional view along the penetration direction of the through hole,
At least one of the first surface and the second surface of the region corresponding to the first part is an inclined surface that increases in distance from the other surface as it approaches the through hole. Item 2. The sealed terminal according to Item 1. In a cross-sectional view along the penetration direction of the through hole,
The thickness of the first part is set to the thickness of the second part on at least one surface side of the first surface and the second surface, which is located in a boundary region between the first part and the second part. The sealed terminal according to claim 1, wherein a step portion thicker than the thickness is disposed.   The sealed terminal according to claim 1, wherein a difference between the thickness of the first part and the thickness of the second part is 0.01 mm or more.   The sealed terminal according to any one of claims 1 to 4, wherein a width of the first portion in a direction orthogonal to the thickness direction of the ceramic plate is 0.01 mm or more and 10 mm or less.