JPH0378783B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method of hermetically sealing a package and a cap of a semiconductor device by seam welding, and an electrode for hermetically sealing a semiconductor used in this hermetic sealing method. .

(Prior art) Conventionally, a pair of conical roller electrodes were attached to metal as a method of covering a laminated ceramic package for semiconductor devices with metal surface treatment (plating) with a metal cap and hermetically sealing the joint by seam welding. A method is used in which the roller electrode is brought into contact with the upper ridgeline of the cap, and the electrode and the ceramic package are moved relative to each other while the roller electrode is rotated to weld the periphery of the package. 6a to 6d show a procedure for welding and sealing a package to which a rectangular seal frame is brazed by a parallel seam welding method using a package linear movement method. First, Figure 6 a, c
A ceramic package 1 is fixed on a table 2 as shown in FIG. The rectangular square cap 3 is held down by the electrode 5 by raising the table 2, and then the table 2 is moved linearly in the direction of arrow A to seal the long side of the cap. After that, Fig. 6 b, d
The table 2 is turned 90 degrees and moved in the direction of arrow B as shown in FIG. The electrode 5 rotates about its axis as the cap 3 moves. This method is the conventional method for sealing rectangular seam packages, and is called linear parallel seam welding because the table moves in a straight line.

In the conventional example shown in FIGS. 6a to 6d, the axis of the roller electrode extends in a direction parallel to the metal cap surface, but it is pivoted in a direction perpendicular to the metal cap surface, and The tip that touches the ridgeline of the cap is shaped like a cone with a sufficiently large base diameter,
There is also a device in which the contactable area of the conical electrode surface is widened so that welding and sealing can be performed only by rotation without linearly moving the rectangular seal frame side (for example, Japanese Patent Publication No. 57-42223).

(Problems to be Solved by the Invention) In this type of seam welding, the contact area of the roller electrode and the heat generation at the welding area are in a contradictory relationship, and the magnitude of the current value of the welding current affects the temperature rise of the entire package. Therefore, it is necessary to appropriately select the relationship between the electrode contact area and the amount of current depending on the size, type, etc. of the package. For example, assuming that the amount of current is the same, the larger the taper angle of the roller electrode at the point of contact with the metal cap, the more the temperature rise of the entire package will be suppressed. However, the roller electrodes used in the conventional seam welding method described above all have a truncated cone shape or a right cone shape, so the taper angle of the electrode surface at the point of contact with the metal cap is It is constant regardless of the position (axial position) of the roller electrode. For this reason, conventionally, there was an inconvenience that seam welding had to be performed by replacing the roller electrode with a roller electrode having an appropriate taper angle each time depending on the type of package. Furthermore, conventional conical roller electrodes have limitations in the taper angle that can be adopted in order to avoid contact with the package frame or table, and in some cases the table must be replaced.

(Means for Solving the Problems) The present invention provides a method for hermetically sealing a semiconductor device by a seam welding method by covering a semiconductor device with a metal cap and contacting a pair of electrodes with two different peripheral edges of the cap. The pair of electrodes has a curved surface in the shape of a paraboloid of revolution, and the position of the curved surface on the electrode where the contact resistance between the curved surface and the peripheral edge of the cap is optimal is selected depending on the type of semiconductor device, and the curved surface is attached to the peripheral edge of the cap. contact,
Seam welding is performed by moving the electrode and the peripheral edge of the cap relative to each other.

Further, the electrode used in the hermetic sealing method of the present invention is
It has a curved surface portion in the shape of a paraboloid of revolution, and the curved surface portion is used as a contact area with the peripheral edge of the cap.

(Example) Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a roller electrode 1 according to an embodiment of the present invention.
0, and FIG. 2 is a plan view showing an example of the case where a rectangular package is hermetically sealed using the hermetic sealing method according to the present invention. As shown in FIG. 1, the roller electrode 10 of this embodiment has a cap contact portion 12 having a curved surface portion of a paraboloid of revolution at the tip of a shaft portion 11. The center line of this paraboloid of revolution coincides with the axis 13 of the shaft portion 11. Therefore, the tangent T at any point P of the cap contact portion 12
The angle (taper angle) θ formed by The contact area with the metal cap 3 is small, and the closer it gets to the shaft portion 11 side, that is, the base 12a of the paraboloid of revolution, the smaller the taper angle θ becomes, and the contact area with the cap 3 increases.

In order to hermetically seal a package using such roller electrodes, as shown in Figure 2, a pair of electrodes 1
0 and 10' are horizontally opposed and pivoted, and the cap contact portions 12 and 12' of the paraboloid of revolution are brought into contact with the two opposing ridges of the square metal cap 3 which is placed over the square seal frame of the package 1. Let and press,
The package 1 is moved in a direction perpendicular to the electrode axis (in the direction of the arrow shown in the figure) and each electrode is rotated around the axis to seal the two long sides of the cap 3, for example, and then the package 1 is moved on a horizontal surface. Rotate it 90 degrees within the box and seal the two short sides in the same way. As explained in FIG. 6, in this embodiment as well, the package 1 is fixed on a table that can be moved back and forth in a straight line.

Here, in the present invention, the distance between the pair of roller electrodes 10, 10' is changed depending on the type, size, external shape, etc. of the package 1, and the contact area between the cap contact portion 12 and the cap ridge, in other words, Select and make contact with the electrode position that provides a good welding result with contact resistance. As a result, various semiconductor devices can be seam welded and sealed using the same electrode without having to replace the roller electrode with a roller electrode having the required taper angle each time.

FIG. 4 is a partial front view showing a comparison between the case where the roller electrode 10 according to the present invention is used and the case where a conventional truncated conical roller electrode 5 (indicated by a broken line) is used in seam welding of semiconductor devices. be. If it is assumed that contacting the package 1 of this semiconductor device at point C of the paraboloid of revolution of the electrode 10 is optimal in terms of contact resistance, then this is compared to the conventional electrode 5.
If welding is attempted using the electrode 5, the large-diameter base 5a of the electrode 5 will come into contact with the table 2 at the position shown in the figure. It must be replaced with the roller electrode 5' and welded by contacting it at the same center radius R. On the other hand, in the case of the roller electrode 10 having a parabolic curved surface of the present invention, any point on the curved surface (for example, point C in the figure)
Since the parts on both sides in the axial direction are convexly curved in the direction away from the part to be welded, there is less risk of contact with a table etc. compared to a right conical shape.

In the above embodiment, the axis of the electrode is held parallel (horizontal) to the surface of the cap, but in some cases, the axis of the electrode 13 may be held perpendicular to the surface of the cap 3a as shown in FIG. The cap may be pivoted, and a contact position with a desired taper angle may be selected on the curved surface of the distal end having a paraboloid of rotation, and the electrode may be brought into contact with the ridgeline of the cap for welding.

In the above embodiments, a rectangular cap is used, but if the cap is circular, select a portion of a pair of parabolic electrodes with an appropriate taper angle and bring them into contact with the cap. of
Seam welding can be done in the same way by rotating it a little more than 180 degrees.

(Effects of the Invention) As explained above, according to the present invention, one electrode can have a plurality of taper angles. There is no need to replace it, and efficient welding and sealing can be performed. In addition, unlike a conical electrode, there is less risk of the electrode base side hitting the support stand, rotary table, etc. of the semiconductor device, and in this respect, the same electrode can effectively perform seam welding of semiconductor devices of various external shapes.

[Brief explanation of drawings]

FIG. 1 is a side view of a welding sealing electrode according to an embodiment of the present invention, FIG. 2 is a plan view showing an example of hermetic sealing using the electrode according to the present invention, and FIG. 3 is a side view of a weld sealing electrode according to an embodiment of the present invention. FIG. 4 is a partial side view illustrating changes in the taper angle of the electrode; FIG. FIG. 5 is a side view of a weld sealing electrode according to another embodiment of the present invention, and FIGS. 6a to 6d are diagrams showing a welding procedure for parallel seam welding using a conventional truncated conical roller electrode. 1...Package, 2...Table, 3...Square cap, 4...Square seal frame, 5,1
0... Roller electrode, 11... Shaft portion, 12... Cap contact portion, θ... Taper angle, T... Contact point tangent.

Claims (1)

[Claims] 1. A method of covering a semiconductor device with a metal cap, contacting a pair of electrodes with two different peripheral edges of the cap, and hermetically sealing the device by seam welding,
The pair of electrodes has a curved surface in the shape of a paraboloid of revolution, and the position of the curved surface on the electrodes is selected so that the contact resistance between the curved surface and the peripheral edge of the cap is optimal depending on the type of semiconductor device. 1. A method for hermetically sealing a semiconductor device, characterized in that seam welding is performed by bringing the electrode into contact with the peripheral edge of the cap and moving the electrode and the peripheral edge of the cap relative to each other. 2. Electrodes used to hermetically seal a semiconductor device by seam welding by covering a metal cap with a pair of electrodes on two different peripheral edges of the cap and having a curved surface portion in the shape of a paraboloid of revolution. An electrode for hermetically sealing a semiconductor device, wherein the curved surface portion is a contact area with the peripheral edge of the cap.