JP2007005046A - Method of joining metal plate and ceramic terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of joining a metal plate and a ceramic terminal capable of improving airtightness of the ceramic terminal by making a clearance between an opening formed on the metal plate and the ceramic terminal as small as possible, on a joining structure of the metal plate and the ceramic terminal. <P>SOLUTION: The method of joining the metal plate and the ceramic terminal comprises a process of forming through-holes 14 on the metal plate 10 by a boring means while positioning it on corner parts of a contour of the ceramic terminal 20; a process of cutting the line between the through-holes 14 by a cutting means, and forming an opening part 12 at which the ceramic terminal 20 is mounted on the metal plate 10; and a process of fitting the ceramic terminal 20 into the opening part 12 and brazing the ceramic terminal 20 to the metal plate 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for joining a metal plate and a ceramic terminal, and more particularly, to a method for joining a metal plate and a ceramic terminal that can improve the airtightness of a brazed portion between the metal plate and the ceramic terminal.

  Conventionally, in a ceramic package formed by brazing ceramic terminals to a metal plate, an opening for mounting the ceramic terminal is provided in the metal plate, and the ceramic terminal is inserted into the opening and brazed. The size of the opening of such a ceramic package is generally formed to be slightly larger than the outer dimension of the ceramic terminal because the ceramic terminal is inserted and arranged, and a predetermined dimension is provided between the inner surface of the opening and the outer surface of the ceramic terminal. Clearance is provided. The ceramic terminal is brazed to the metal plate with a brazing material such as silver solder after the ceramic terminal is disposed in the opening of the metal plate, and is sealed to the metal plate. When sealing a ceramic terminal to a metal plate, the larger the clearance, the easier it is to arrange the ceramic terminal, which is advantageous, but on the other hand, the airtightness when the ceramic terminal is sealed is reduced. There is an inconvenience.

  Further, the opening 12 provided in the metal plate 10 for mounting the ceramic terminal is often formed by cutting the metal plate 10. When the opening 12 is formed by this cutting method, the rounded portion R is formed at the corner of the opening 12 as shown in FIG. For this reason, when it is going to form the opening part 12 so that the ceramic terminal 20 can be arrange | positioned, the rounded part R of a corner part and the corner part of the ceramic terminal 20 must be made not to interfere, and clearances other than the rounded part R 40 becomes larger than necessary.

In recent years, since the ceramic terminal 20 is disposed in the opening 12 by an automatic process, the necessity of increasing the clearance between the opening 12 and the ceramic terminal 20 to facilitate the placement of the ceramic terminal 20 is reduced. ing. On the other hand, in sealing the ceramic terminal 20, high sealing performance is required year by year, and the clearance between the opening 12 of the metal plate 10 and the ceramic terminal 20 attached thereto can be made as small as possible. It is desired.
Japanese Patent Laid-Open No. 9-92747 Japanese Patent Laid-Open No. 9-246440

  Patent Document 1 or 2 discloses a countermeasure method for the difference in thermal expansion coefficient between a metal plate used as a heat sink and a ceramic terminal in a ceramic package. However, none of the publications discloses a processing method for enhancing the sealing performance of the sealing portion of the ceramic terminal to the metal plate when the metal plate and the ceramic terminal are joined.

  Since the size of the opening 12 (clearance size) is restricted by the size of the rounded portion R formed at the corner of the opening 12 as shown in FIG. There are limits to the clearance reduction with 10 cutting techniques. Therefore, the present invention can reduce the clearance between the opening 12 formed in the metal plate 10 and the ceramic terminal 20 as much as possible in the joint structure of the metal plate 10 and the ceramic terminal 20 and improve the airtightness of the ceramic terminal 20. An object of the present invention is to provide a possible method for joining the metal plate 10 and the ceramic terminal 20.

  The present invention provides a step of forming a through hole in a metal plate by aligning with a corner portion of the outer shape of the ceramic terminal by a hole drilling means, and cutting the space between the through holes by a cutting means, and the ceramic terminal on the metal plate A metal plate comprising: a step of forming an opening in which the metal plate is mounted; and a step of brazing the metal plate and the ceramic terminal by disposing the ceramic terminal in the opening. This is a method of joining ceramic terminals.

Further, in the step of forming the opening, the metal plate is cut so that a part of the outer peripheral edge of the through hole remains.
As a result, the clearance between the opening and the ceramic terminal can be made as small as possible while leaving the rounded portion of the through hole and relaxing the stress concentration, and the ceramic terminal can be sealed in a highly airtight state. It becomes possible.

  According to another aspect of the present invention, a step of forming a through hole in a metal plate by aligning with a corner portion of the outer shape of the ceramic terminal by drilling means, and a position of the ceramic terminal on the metal plate by aligning with the through hole A step of arranging a mask in which an opening hole for etching is formed in accordance with a region where the metal plate is disposed, etching the metal plate to form an opening, and arranging the ceramic terminal in the opening, And a method of joining the ceramic terminal to the ceramic terminal.

Further, the etching mask is characterized in that the etching opening is formed so that the opening formed by etching communicates with part or all of the through hole.
As a result, the clearance between the opening and the ceramic terminal can be made as small as possible while leaving the rounded portion of the opening and relaxing the stress concentration, and the ceramic terminal can be sealed in a highly airtight state. It becomes possible. Moreover, since it becomes a form which is easy to mass-produce, manufacturing cost can be held down.

  According to the method for joining a metal plate and a ceramic terminal according to the present invention, the corner portion of the opening has a rounded portion capable of sufficiently relaxing stress concentration, and the clearance between the opening and the ceramic terminal is made as much as possible. Can be made smaller. As a result, the brazed portion can be reduced, the brazing material can be saved, the airtightness between the metal plate and the ceramic terminal can be greatly improved, and a highly reliable product can be provided. Become.

(First embodiment)
Embodiments of a method for joining a metal plate and a ceramic terminal according to the present invention will be described below with reference to the drawings.
1A and 1B are a plan view and a cross-sectional view taken along line AA, showing a state where a metal plate and a ceramic terminal are brazed. FIG. 2 is a plan view showing a first step in the step of forming the opening in the present embodiment. FIG. 3 is a plan view showing a second step in the step of forming the opening in the present embodiment. FIG. 4 is an enlarged view of a portion B in FIG.

The metal plate 10 in the present embodiment is made of Kovar (Fe—Ni—Co). Since Kovar has a thermal expansion coefficient that is very close to that of ceramics, Kovar is often used in the manufacture of products made by integrating the two.
The metal plate (Kovar plate) 10 is used as, for example, a constituent material of a case portion of a ceramic package and has a heat dissipation function. The metal plate 10 and the ceramic terminal 20 are joined by a brazing material 30 such as silver brazing filled in a clearance portion 40 between the opening 12 formed in the metal plate 10 and the ceramic terminal 20. The brazing filler metal 30 is filled in every corner of the clearance portion 40 by the action of surface tension.

Hereinafter, a method for forming the opening 12 of the metal plate 10 will be described.
First, the through hole 14 is formed at a required position of the metal plate 10 by a small diameter end mill (not shown) which is a hole drilling means. In the present embodiment, as shown in FIG. 2, the through holes 14 are formed at the four corners of the rectangle corresponding to the finished shape of the opening 12.
Next, as shown in FIG. 3, it cuts so that the adjacent through-holes 14 may be continued linearly with the wire saw (not shown) which is a cutting means. As shown in FIG. 4, the metal plate 10 is cut by the wire saw cut so that a part of the outer peripheral edge of the through hole 14 remains.
In this wire saw cutting, it is preferable that the angle α formed by the cutting positions (or cutting positions) to the through hole 14 position by the wire saw exceeds 90 °.

  The opening 12 formed in this way has a rounded portion R formed by a part of the outer peripheral edge of the through hole 14 at the corner of the opening 12, and the rounded portion R is an opening in which the ceramic terminal 20 is disposed. It is formed outside the corner portion of the region. That is, the opening 12 in the rectangular region in which the ceramic terminal 20 is disposed can be formed without depending on the rounded portion R. Thereby, the clearance 40 between the opening 12 where the ceramic terminal 20 is disposed and the ceramic terminal 20 can be made as small as possible.

  The ceramic terminal 20 is arranged and brazed to the opening 12 formed in this way. After the ceramic terminals 20 are disposed in the opening 12 by automatic means (not shown), the clearance terminals 40 are joined to each other using a brazing material 30 such as silver brazing. The metal plate 10 and the ceramic terminal 20 are heated and brazed in a heating furnace heated to a temperature at which the brazing material 30 is melted. The brazing material 30 is filled in the clearance 40 and the rounded portion R between the metal plate 10 and the ceramic terminal 20, and the ceramic terminal 20 is brazed in an airtight manner.

  In the present embodiment, it is described that the angle α formed by the cutting position (or the cutting position) to the through hole 14 position by the cutting means exceeds 90 °, but is not necessarily limited to this angle. It is not a thing. The point is that the angle α from the center O of the through hole 14 to the cutting start position of each wire saw is implemented as long as the opening 12 is formed so that a part of the outer peripheral edge of the through hole 14 remains. Of course, the angle may be outside the range of the example.

(Second Embodiment)
Next, 2nd Embodiment in the joining method of the metal plate and ceramic terminal concerning this invention is described according to FIGS.
FIG. 5 is a plan view showing a first step in the step of forming the opening in the second embodiment. FIG. 6 is a plan view showing a second step in the step of forming the opening in the second embodiment. FIG. 7 is a plan view of a metal plate in which openings are formed according to the second embodiment. FIG. 8 is an enlarged view of a portion C in FIG.
The metal plate 10 used in the present embodiment is made of Kovar as in the first embodiment, and a thin plate having a thickness of about 1 mm is used.

Below, the formation method of the opening part 12 to the metal plate 10 in this Embodiment is demonstrated.
First, through holes 14 are formed at four corners of a rectangle corresponding to the finished shape of the opening 12, as shown in FIG.
Next, as shown in FIG. 6, the etching mask 50 for forming the opening 12 is overlaid on the metal plate 10, and the opening 12 is formed in the metal plate 10 by performing an etching process. In the etching mask 50, a rectangular etching opening 52 is formed in accordance with the hole shape of the opening 12 formed in the metal plate 10 in order to place the ceramic terminal 20. In this embodiment, a relatively thin metal plate 10 having a thickness of 1 mm is used. The thickness of the metal plate 10 when the opening 12 is formed by etching is not particularly limited. However, since the finished dimension of the opening 12 varies depending on the plate thickness, the shape of the etching mask 50 (particularly, depending on the thickness) It is necessary to set the shape of the etching mask opening 52).

FIG. 7 shows a state where the metal plate 10 is etched using the etching mask 50. An opening hole 12 is formed in the central portion of the metal plate 10. The opening 12 is in a state where it communicates with a through-hole 14 formed in advance by means of drilling means.
The opening 12 of the metal plate 10 formed by the etching process is in a state of opening in a slightly larger range than the etching opening 52 in terms of etching characteristics. Therefore, when the opening 12 having the same size as that of the first embodiment is formed, the size of the etching opening 52 is set slightly smaller than the size of the opening 12 to be formed in the metal plate 10. To do.

  Further, the etching may be performed using an etching mask 50 formed so that the outer peripheral edge of the etching opening 52 is slightly inside the through holes 14 or slightly overlaps the through holes 14. When etching is performed using such an etching mask 50, the opening 12 can be formed in the metal plate 10 with a part of the outer peripheral edge of the through hole 14 remaining.

  According to the above-described method of forming the opening 12 by etching, so-called sagging D is formed at the connection portion between the corner portion of the opening 12 and the through hole 14 as shown in FIG. In this way, when the corners of the connecting portion between the rounded portion R formed in the corner portion of the opening 12 and the side portion of the opening 12 have a curved continuous shape, the ceramic terminal 20 and the metal plate 10 are joined after joining. The effect of relieving the concentration of stress acting on the corner portion of the opening 12 between the two is obtained.

As described above, the method for joining the metal plate and the ceramic terminal according to the present invention has been described based on the embodiments. As a specific product to which the present invention is applied, a metal case for a ceramic package as shown in FIG. Is mentioned. FIG. 9 is a perspective view showing a metal case for a ceramic package formed by applying the present invention.
The metal case 70 for a ceramic package is formed by assembling a bottom plate 72 and a side plate 74 (here, a Kovar plate is used as in the above embodiment). In the ceramic package here, the ceramic terminal 20 is joined to each of the pair of opposing side plates 74. The ceramic terminal 20 functions as a relay body that electrically connects an electronic component mounted inside the ceramic package metal case 70 to a wiring board or the like outside the ceramic package metal case 70.

  When assembling the ceramic package metal case 70, first, a pair of side plates 74 to which the ceramic terminals 20 are joined and a side plate 74 facing the pair of side plates 74 are set in an assembly jig (not shown). Then, the assembly jig is aligned with the upper surface of the bottom plate 72, the four side plates 74,... Are placed on the bottom plate 72, and then brazed to be assembled into a ceramic package. The metallized portion 76 of the ceramic terminal 20 is connected to an electronic component in the case by wire bonding, and is electrically connected to a wiring board outside the case by a lead wire. The bottom plate 72 and the side plate 74 are brazed and the ceramic terminal and the side plate 74 are brazed simultaneously.

In the semiconductor device formed in this way, the sealing property between the ceramic terminal and the side plate 74 is improved, and the ceramic terminal can be brazed with high accuracy.
Further, since the rounded portion R having an appropriate size is formed in the corner portion of the opening portion 12, various stresses generated between the ceramic terminal and the side wall 74 can be smoothly transmitted, and the stress concentration can be reduced. it can.

It is the top view and AA sectional view which show the state by which the metal plate and the ceramic terminal were brazed. It is a top view which shows the 1st process in the formation process of the opening part in this embodiment. It is a top view which shows the 2nd process in the formation process of the opening part in this embodiment. FIG. 4 is an enlarged view of a portion B in FIG. 3. It is a top view which shows the 1st process in the formation process of the opening part in 2nd Embodiment. It is a top view which shows the 2nd process in the formation process of the opening part in 2nd Embodiment. It is a top view of the metal plate in which the opening part was formed by 2nd Embodiment. FIG. 8 is an enlarged view of a portion C in FIG. 7. It is a perspective view which shows the metal case for ceramic packages formed by applying this invention. It is a top view which shows the example of joining of the metal plate and ceramic terminal in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Metal plate 12 Opening part 14 Through-hole 20 Ceramic terminal 30 Brazing material 40 Clearance part 50 Etching mask 52 Etching opening 70 Ceramic package metal case 72 Bottom plate 74 Side plate 76 Metallization part D Darre R Earl part

Claims (4)

A step of forming a through hole in the metal plate by aligning with the corner portion of the outer shape of the ceramic terminal by means of drilling means;
Cutting between the through holes by a cutting means to form an opening in which the ceramic terminal is mounted on the metal plate;
A method for joining a metal plate and a ceramic terminal, comprising the step of placing the ceramic terminal in the opening and brazing the metal plate and the ceramic terminal.   2. The method of joining a metal plate and a ceramic terminal according to claim 1, wherein in the step of forming the opening, the metal plate is cut so that a part of the outer peripheral edge of the through hole remains. A step of forming a through hole in the metal plate by aligning with the corner portion of the outer shape of the ceramic terminal by means of drilling means;
A step of aligning with the through hole, disposing a mask in which an opening for etching is formed in a region where the ceramic terminal is disposed on the metal plate, and etching the metal plate to form an opening; ,
A method for joining a metal plate and a ceramic terminal, comprising the step of placing the ceramic terminal in the opening and brazing the metal plate and the ceramic terminal.   4. The etching mask, wherein the etching opening is formed so that the opening formed by etching communicates with a part or all of the through hole. Joining method of metal plate and ceramic terminal.

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