JPS58137315A - Supporting structure of oscillator - Google Patents

Abstract

PURPOSE:To reduce the size of an oscillator and to improve its performance by forming a metallic film near the nodal point or line of the oscillator, connecting joint members thereupon, and bonding the joint members to a supporting member by thermocompression. CONSTITUTION:Crystal 4 has a joint part 4a on the flank by rounding a sheetlike AT plate crystal piece blank and also has a slanting surface 4b near the external circumference and a flat surface 4c at the center part. The nodal line in the center of the width of the joint part 4a; a joint film 5a formed by extending a lead electrode film 5b is jointed to the joint part 4a, and the lead electrode film 5b and an energizing electrode film 5c are jointed to the slanting surface 4b and flat surface 4c. Soft metal (Au) is bonded onto the nodal line of the joint film 5a by a wire bonder to form the joint member 7, which is fixed to the supporting member 9 by thermocompression bonding. The formation of the joint member employs the bonding, so the mass is uniform and tight supporting is realized unlike adhesion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support structure for a vibrator, which rigidly supports the vibrator near the dally point or line of the vibrator, thereby reducing the size of the vibrator and improving its performance. The purpose is to

Previously, it has been known that supporting a vibrator at a nodally point or a nodally line (the neutral point or side of vibration, where the surrounding area does not move even though the surroundings vibrate and the vibration becomes O) greatly improves performance. I know it's good in theory.

However, in the case of a large oscillator, for example, an AT plate crystal piece of 80 mm or more, supporting the oscillator with good properties may be achieved even if the oscillator is supported slightly off the nodal line rather than on the nodal line as in the above theory. Because mass production was possible, there was less need for support on the no-dary line, which is extremely difficult to work with. In other words, the front view shown in FIG. 1 shows a conventional crystal resonator, in which the crystal piece 1 and the support member 2 are adhesively fixed with a conductive paste 6, and the conductive paste 6 covers not only the adhesive surface of the crystal piece 1 but also the side surface. However, the properties were good enough to withstand use. However, the properties were good enough to withstand use.
If the fixing structure according to the above conventional example is adopted for small crystal pieces of y5wm or less, when the adhesive flows out to the side where the nodaly line is located or the slope near the adhesive surface, as in the case of the eight doors, this The effect of the adhesive that flows out on performance cannot be ignored.

In other words, the C1 value is large, the Q value is small, and the variation in frequency and temperature characteristics is greater than the proportion of the difference in the diameter of the crystal piece, so the influence of the adhesive flowing onto the slope on performance can be ignored. It cannot be done. Also, unlike the above-mentioned embodiments, bonding only on the side surfaces had the disadvantage of poor impact strength. Further, although not shown in the drawings, experiments were conducted in which molten metals such as solder and silver solder were used to improve strength, but this also had problems in terms of performance due to flowing out, and this could not be used.

In order to improve the above-mentioned drawbacks, the present invention combines solid objects, and will be explained below with reference to the drawings based on examples.

FIG. 2 is a sectional view of the crystal piece for explaining the nodaly line of the AT plate crystal piece, and X and Y'Z respectively indicate the coordinate axes of the crystal piece. 4 is a crystal piece, 5 is a metal film, and 6 is a nodaly line. The arrow 10 in Fig. 2 is an enlarged representation of the vibration direction and size of the crystal. Above the sodary line 6 is the neutral line and there is no displacement, and the displacement near the sodary line 6 is small and the surface This indicates that the displacement is large, and the directions of the arrows are opposite to each other above and below the nodaly line in the X-axis direction.

The present invention has focused on this point and has a structure in which support members are used to rigidly support only the portions near the sodary line 6 where displacement is small, and by using a method such as diffusion (thermo-compression bonding).

FIG. 3 is a front view of a crystal blank in an embodiment of an AT plate crystal resonator to which the present invention has been applied, showing the crystal blank after the bonding process has been completed, and FIG. 4 is a front view of an embodiment of the present invention. FIG. 5 is a plan view of the embodiment shown in FIG. 4.

For convenience of explanation, the sealed tube is not shown in both FIGS. 4 and 5. Moreover, X, Y, and Z in FIG. 3 represent the coordinate axes of each crystal. The crystal piece 4 is made by rounding a sheet-like AT plate crystal piece blank to form a joint part 4a on at least the Y'-Z' side of the side surface, and then the width of the joint part 4a is set to 150μ.
Bevel the area near the outer periphery and wrap the center part, leaving about m, so that there is a slope 4b near the outer periphery and a flat surface 4c in the center.
is formed. As shown in FIG. 3, the nodaly line 6 is located at the center of the width (approximately 150 μm) of the joint portion 4a. A bonding film 5a, which is an extension of the lead electrode film 5b, is bonded to the bonding portion 4a of the crystal piece 4, and a lead electrode film 5b and an excitation electrode film 5c are bonded to the sloped surface 4b and the flat surface 4c.

Note that the bonding film 5a, the lead electrode film 5b, and the excitation electrode film 5
The metal film 5 made of C is formed by a method such as vapor deposition or sputtering, and is formed by, for example, Cr with a thickness of 100 to 500X and Au with a thickness of 1. so
o to 2o and oooAk are laminated, and the lead electrode film 5b and the excitation electrode film '5c are formed on the same surface as in the prior art. In order to save Au, the metal film 5 may be formed by reducing the thickness of Au and inserting an Ag layer between Cr and Au.

Next, using a wire bonder (not shown), a soft metal such as an Au wire is bonded onto the sodaly line 6 of the bonding film 5a, leaving the bonding head to form a bonding member 7. The diameter of the bonding member 7 can be changed from 30 to 100 μm by changing the diameter of the Au wire and the bonding pressure (in this example, the diameter of the bonding member 7 is approximately 70μm and the Au wire is 33×6μm).
A uniform mass can be appropriately selected within the range of .mu.m), and the joining member 7 will not be joined to anything other than the joining portion 4a of the crystal piece 4.

Next, we will discuss thermocompression bonding for attaching the crystal piece to the support member. First, as shown in FIG. 3, a crystal piece 4 to which a bonding member 7 is bonded by bonding is placed between support members 90 having an Au layer provided on a substrate 8, as shown in FIG. Next, the bonding member 7 and the supporting member 9 are bonded together by thermocompression, but the conditions for thermocompression bonding are determined by a combination of time, temperature, degree of vacuum, and pressing force. When pressed at approximately 101+1/m and left as is for several hours, Au diffused into each other and thermocompression bonding was completed. Since the force supporting the crystal piece is approximately proportional to the bonding area, in order to increase the supporting force, it is good to increase the number of bonding points on the nodaly line and increase the number of bonding members for bonding. Au is the best soft metal to be used as the joining member, but since it is expensive, it may be replaced with soft metals such as Ag, Pd, AI, In, etc., or a combination thereof. Although the surface of the support member is provided with an Au layer, other methods may be considered, such as two layers of Ag and Au, similar to the joining member. Further, the shape of the support member may be round, square, or grooved, depending on the combination of the fixing force and the shape of the crystal piece. Further, the method of thermocompression bonding is not limited to the above example, and any method that can bond each layer of the bonding member and the support member by thermal diffusion can be applied. Furthermore, the present invention can be applied not only to quartz crystals but also to vibrators exhibiting a thickness-shear piezoelectric effect, and can also be applied to vibrators that are generally said to be rectangular (not shown). A bonding film may be provided on top and support may be provided at this portion.

As explained above, the crystal piece is supported very close to the nodaly line, and the joining member does not flow out to places other than the vicinity of the nodaly line, such as on slopes, and the joining member is formed JJ''
- Since it is bonded, its mass is uniform, and the support does not affect the cable characteristics. In addition, since the crystal piece is fixed with a metal bonding member, unlike adhesives, it has a strong supporting force and excellent impact resistance, and has improved long-term durability.

Therefore, the present invention has the great effect of providing a very stable and small-sized vibrator.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a conventional support structure for a crystal resonator, and FIG. 2 is a cross-sectional view of a crystal resonator piece to explain a nodaly line, and X, Y', and Z' indicate the coordinate axes of the crystal resonator. Third
From the figures, FIG. 5 is a diagram showing one embodiment of the present invention, and FIG.
The figure is a front view showing the crystal piece after the bonding process, Figure 4 is a front view of a crystal resonator using the crystal piece shown in Figure 3, and Figure 5 is a front view of the crystal piece after the bonding process.
The figure is a plan view of FIG. 4. 4...Crystal piece, 4a...Joint part, 5.
...metal film 5a...bonding film, 5b...
...Lead electrode film, 5c...Excitation electrode film, 6
...Nodally line 7...Joining member,
9...Supporting member. Figure 1 Figure 2 Figure 3 Figures 1-4

Claims (1)

[Claims] forming a metal film near the nodally line or nodally point of the vibrating element, and joining a bonding member on the nodally line or nodally point on the metal film;
A support structure for a vibrator in which the bonding member is heat-pressed as a support member.