JPS607492Y2 - Stem for hermetic sealing - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a hermetic sealing stem.

For example, a surface wave filter element has a comb-shaped input electrode and an output electrode arranged on a substrate made of a piezoelectric material, and an electric current applied between two input terminals provided on the input electrode. A mechanical surface wave is generated on the surface of the piezoelectric material through the input electrode, and this mechanical surface wave is converted into an electrical signal again from the output electrode, and this electrical signal is sent to the two output terminals provided on the output electrode. It is designed to be taken out from between.

The above-mentioned surface wave filter element is usually mounted and fixed on one main surface of the hermetic sealing stem, that is, the stem header surface, and thin bonding wires are connected to the input terminal and output terminal, respectively, to the lead wires planted in the hermetic sealing stem. They are bonded together and then covered with a cap for airtight sealing.

One of the four terminals, the input terminal and the output terminal, is directly bonded to the hermetic sealing stem using a bonding wire and is grounded.

Next, an example of a conventional hermetic sealing stem will be explained with reference to FIGS. 1 and 2.

That is, three through holes 2 are bored at desired positions in a circular stem metal plate 1, and electrode leads 4 are implanted in each through hole 2 via an insulating member 3 such as solder glass. A recess 5 is formed at a desired position of the stem metal plate 1 from 1° on the back surface of the stem header 1 □, and an earth lead 7 is welded to the recess 5 with a brazing material 6 to form a hermetically sealed stem.

However, in the hermetic sealing stem having such a structure, it is not only difficult to form the recess 5 by press working, but also the dotted line placed and fixed on the stem header surface 1 □ of the stem metal plate 1 as shown in FIG. Terminals 9 and 10 of the surface wave filter element 8 shown as
Of these, the bonding wire 11 that connects the grounded terminal 9 and the stem header surface 11 and the bonding wire 12 that connects the ungrounded terminal 10 and the top surface 41 of the electrode lead 4 have different lengths. line 11.12
The junction point 13 to the stem header surface 1□ and the top surface 41
Since there is a difference in level between the bonding points 14, a bonding device or the like is used to connect each bonding wire 11, 12 to the terminals 9, 10 of the surface wave filter element 8 and the stem header surface 11.
When bonding to the top surface 4□, workability was poor and also caused variations in bonding strength at bonding points 13 and 14.

This also applies to a structure in which the recess 5 is not provided and the ground lead 7 is directly brazed to the back surface 1□ of the stem metal plate 1.

The present invention was developed in view of the drawbacks of the conventional hermetic sealing stem mentioned above, and it is an airtight sealing system in which the concave part for the ground lead soldering is easy to shape, and furthermore, it is easy to bond the bonding wire. The aim is to provide stems for

Next, one embodiment of the hermetic sealing stem of the present invention will be described with reference to FIGS. 4 and 5.

That is, three through holes 22 are formed in a circular stem metal plate 21.
The electrode leads 24 are implanted in each through hole 22 through an insulating member 23 such as solder glass, and the process is performed simultaneously with the process of drilling the through hole 22 described above or in a separate process. Then, a protrusion 25a is formed on the stem header surface 21□, and a recess 25b is formed on the back surface 21° of the stem header surface 211 corresponding to the protrusion 25a, and the earth lead 27 is welded to this recess using the brazing material 26. It is characterized by

The method for forming the protrusion 25a and the recess 25b needs no explanation, and can be easily formed by press working.

Next, a state in which a surface wave filter is mounted and fixed on the hermetic sealing stem of this embodiment and bonded with a bonding wire will be described with reference to FIG. 6.

That is, among the terminals 29 and 30 of the surface wave filter element 28 shown by dotted lines placed and fixed on the stem header surface 21□ of the stem metal plate 21, the terminal 29 to be grounded and the protrusion 25a
The bonding wire 31 that connects to the top surface 25□ of the electrode lead 24 and the bonding wire 32 that connects the ungrounded terminal 30 and the top surface 24□ of the electrode lead 24 differ somewhat depending on the height of the protrusion 25a, but have the same length. Furthermore, the bonding portion 33 and the top surface 24 of the bonding lines 31 and 32 to the top 25□
It is possible to reduce the level difference between the bonding point 34 and the terminal 29.3 of the surface wave filter element 28 using a bonding device or the like.
0 and the top surface 251 of the protruding portion 25a and the top surface 24□ of the electrode lead 24, the workability is good and the bonding strength at the bonding points 33 and 34 is uniform.

That is, by adopting the structure of this embodiment, firstly, the ground lead and the electrode lead are positioned together by the through hole and the recess, so that mass production is possible.

Second, the difference in level between the top surface of the protrusion, the top surface of the electrode lead wire, and the terminal of the surface wave filter placed and fixed on the stem header is reduced, improving bonding workability and further increasing the strength of the bonding point. Can be done evenly.

Furthermore, by using a suitable brazing material, it becomes possible to assemble the electrode lead and the ground lead in the same process.

Although the above embodiment describes the case of a surface wave element having four terminals, the present invention is not limited to this, and can also be applied to a hermetic sealing stem for a semiconductor element, especially an IC having a large number of terminals. Of course.

As mentioned above, the hermetic sealing stem of the present invention has a structure that is extremely advantageous for attaching earth leads, welding bonding wires, etc., and has great industrial value.

[Brief explanation of the drawing]

Figures 1 to 3 are views showing a conventional hermetic sealing stem, with Figure 1 being a top view and Figure 2 being a view of Figure 1 taken along line A-A' and viewed in the direction of the arrow. 3 is an explanatory sectional view showing a surface wave filter element mounted and fixed and wired, and FIGS. 4 to 6 are views showing one embodiment of the hermetic sealing stem of the present invention. Figure 4 is a top view, Figure 5 is a cross-sectional view of Figure 4 taken along line B-B' and viewed in the direction of the arrow, and Figure 6 is a surface wave filter element mounted and fixed and wired. It is an explanatory sectional view showing a state. 1.21...Metal plate for stem, 4,24...
... Electrode lead, 5, 25b ... Recessed part, 7,
27... Earth lead, 8, 28...
Surface wave filter element, 11, 12, 31, 32...
...Bonding wire, 25a...Protrusion.

Claims (1)

[Scope of utility model registration request] A stem metal plate, an electrode lead implanted in a through hole drilled at a desired position of the stem metal plate via an insulating member, and a protrusion formed on a stem header surface of the stem metal plate. A recess formed on the back surface of the stem header surface of the stem metal plate corresponding to the protrusion, and an earth lead fixed to the recess through a brazing material. Stem for hermetic sealing.