JP3069366B2 - Manufacturing method of crystal unit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a crystal resonator and a processing method thereof,
In particular, it relates to improvement of productivity and yield.

(Technical Background of the Invention and Problems Thereof) For example, in the process of manufacturing a quartz oscillator, a strip-shaped quartz wafer is cut out from a crystal of artificial quartz, and blanks corresponding to individual quartz oscillators are obtained from the quartz wafer. ing.

Conventionally, in a processing method for obtaining a blank from a quartz wafer, first, at the stage of the quartz wafer, polishing is performed to a thickness having a desired resonance frequency. This quartz wafer is, for example, 30 mm long,
It is about 10mm wide and 0.5mm thick.

Then, as shown in FIG. 2, the main surface 2a of the crystal wafer 2 is bonded to the inclined surface 1a of the jig 1 whose surface is formed in a sawtooth shape.

Then, a portion where the main surface and the side surface of the crystal wafer 2 held by the jig 1 intersect, that is, the ridge 2b is polished and removed. The same operation is repeated four times to grind each ridge 2b in the width direction of the quartz wafer 2 to form a knife edge having an angle of about 5 °.

Then, the main surfaces of the crystal wafers 2 are adhered and stacked in order, and several tens of the wafers are adhered. Then, using a multi-blade cutter in which a number of blades are stretched in parallel at intervals corresponding to the cutting width, the stacked quartz wafers 2 are simultaneously cut into a predetermined width, for example, a width of 2 mm in a direction perpendicular to the main surface. .

Next, the quartz wafer 2 is separated into individual quartz pieces, that is, blanks, stored in a cylindrical container together with an abrasive, and the cylindrical container is rotated to grind the entire periphery.

Then, a vibrating electrode is formed on the main surface of the blank whose edge angle has been polished and removed.

The vibration is confined in the center of the plate surface by shaping the thickness of the blank end portion to be thin so that good vibration characteristics can be obtained.

However, in such a method, the work of polishing and removing the ridge in the width direction of the quartz wafer is troublesome, and the productivity is significantly reduced. That is, the widthwise ridge of a plate-like wafer having a thickness of about 0.5 mm must be polished and formed into a knife-edge shape having an angle of about 5 °. However, since the edge of the thin quartz wafer must be polished diagonally, damages such as cracks, chips, etc., are very likely to occur. In this polishing operation, since the main surface is machined, the vibration characteristics that cause damage here are significantly impaired, and cannot be put to practical use as a quartz oscillator. In addition, such a work has a problem in that it requires skill because it depends on manual work, and is likely to become a bottleneck in production.

(Object of the Invention) The present invention has been made in view of the above circumstances, and a quartz crystal resonator that streamlines the processing steps of a crystal blank, has less occurrence of defects during manufacturing, and can increase productivity, and a crystal resonator therefor. It is an object to provide a processing method.

(Summary of the Invention) The present invention relates to a quartz vibrator in which a rectangular crystal blank is obliquely cut off from both sides in the longitudinal direction, stored in a cylindrical container that rotates together with an abrasive, and polished to form an excitation electrode on a main surface. The main surface of the crystal wafer and the strip-shaped crystal wafer are bonded and bonded, cut to a predetermined width at right angles to the main surface, and both ends of the main surface are cut off diagonally from both sides to separate individually and with the abrasive. The present invention is characterized by a processing method in which a cylindrical container is housed in a cylindrical container, and the cylindrical container is rotationally driven and polished to form an excitation electrode on a main surface.

(Example) Hereinafter, a processing method according to an example of the present invention will be described in detail with reference to FIGS. 1 (a) to 1 (e).

First, in a first step, as shown in FIG. 1 (a), a predetermined number of crystal wafers 11 are stacked with their main surfaces 11a bonded together. This bonding operation is performed using, for example, a paraffin-based thermoplastic adhesive.

Next, in the second step, the quartz wafer 11 is cut into a predetermined width w, for example, a width of 2 mm at right angles to the main surface.

Then, in the third step, as shown in FIG.
The two ends of the main surface 11a of the crystal wafer 11 cut to a predetermined width in the step are cut obliquely from both sides. This operation can be efficiently performed by, for example, an automatic outer peripheral blade cutter using a diamond wheel.

Next, in a fourth step, the quartz wafers bonded in the first step are heated to, for example, about 100 ° C. and separated into individual pieces, for example, so-called blanks 12 having a shape as shown in FIG. 1 (c). .

In the fifth step, the blank 12 is stored together with the abrasive in a cylindrical container 13 made of, for example, brass as shown in FIG. 1 (d) and hermetically closed, and the container 13 is driven to rotate. Then, the entire circumference of the blank 12 is polished, and all the ridge angles are formed into curved surfaces, for example, as shown in FIG. 1 (e). In this polishing, both ends of the blank 12 are narrow, so that they are sufficiently polished not only in the width direction but also in the thickness direction, so that the thickness of the ends can be reduced. Therefore, good vibration characteristics can be obtained in which vibration energy can be confined at the center of the plate surface.

Then, an excitation electrode is formed on the main surface of the blank by vapor deposition or the like, and piezoelectric vibration is excited via this electrode.

This eliminates the need for the work of polishing the ridge between the main surface 11a and the side surface from the quartz wafer 11 as in the conventional processing method, so that the productivity can be significantly improved.
The work of diagonally cutting both sides of both ends of the main surface 11a of the crystal wafer 11 cut to a predetermined width w can be performed by, for example, an automatic outer blade cutter using a diamond wheel, so that work efficiency is good and defective products are generated. Also less.

In this conventional processing method, it took about one hour to obtain 400 blanks, but in the above embodiment, the productivity can be improved by a factor of 10 or more.

The processing surface of this cutting process is the side surface of the crystal wafer 11, and even if some damage such as cracks occurs during this processing, it can be removed by polishing with a polishing agent in a later process, and the defective product can be significantly reduced. is there.

(Effects of the Invention) As described in detail above, according to the present invention, it is possible to provide a method for processing a crystal blank that can streamline processing steps, increase productivity, and reduce occurrence of defects. it can.

[Brief description of the drawings]

1 (a) to 1 (e) are views for explaining a processing method according to one embodiment of the present invention, and FIG. 1 (a) is a view for explaining first and second steps. (b) is a view for explaining the third step, (c) is a perspective view of the blank obtained by the fourth step, (d) is a perspective view of a cylindrical container for polishing the blank, FIG. 3E is a perspective view showing the polished blank. FIG. 2 is a side view showing a conventional method for processing a quartz wafer. 11 ... Crystal wafer 11a ... Main surface 12 ... Blank 13 ... Cylindrical container

Claims (2)

(57) [Claims] 1. A quartz crystal blank having a rectangular shape is housed in a cylindrical container, and the quartz crystal blank is entirely polished by rotation of the cylindrical container. A method for manufacturing a crystal frequency, which performs a curved surface processing to reduce the size, wherein both ends in the longitudinal direction of the crystal blank are obliquely cut off from both sides, and the crystal blank is thrown into the cylindrical container and polished. Method. 2. A first step of bonding and stacking a main surface of a rectangular crystal wafer, a second step of cutting the crystal wafer into a predetermined width at right angles to the main surface, and a main surface of the crystal wafer. A step of obliquely cutting both ends of the wafer from both sides, a fourth step of individually separating the wafers bonded in the first step to obtain a quartz blank, and a cylindrical container with the quartz blank together with an abrasive. A method for manufacturing a crystal resonator, comprising: a fifth step of rotating the cylindrical container and polishing the cylindrical container, and a sixth step of forming an excitation electrode on the main surface of the crystal blank.