JP4532328B2 - Wet etching equipment for piezoelectric wafers - Google Patents

Description

          The present invention relates to a wet etching apparatus for a piezoelectric wafer with little variation in etching amount.

          In recent years, piezoelectric vibrators are often used in general electronic devices including communication terminals such as mobile phones, but on the other hand, very high-precision product specifications used for crystal oscillators for base stations, etc. For crystal resonators that require a large number of crystal resonators, a large number of crystal resonators are made on a single crystal wafer, processed in a batch, and divided into each crystal resonator in the final process. In some cases, the manufacturing method is accommodated.

          This is due to the recent trend of transmission systems in the communications field as the core, and the mounting parts, including crystal units, are rapidly becoming smaller and lower in height from the market. This is partly due to the demand for lower prices.

When wet etching is used to process a large number of crystal resonators on a single crystal wafer, a conventional vertical swing type wet etching system uses a heater to heat the etchant under the wet etching tank. Etching was performed by swinging the wafer up and down in the warmed etchant flow.
JP 2000-252255 A

          In addition, the applicant did not find any prior art documents related to the present invention by the time of filing of the present application other than the prior art documents specified by the above prior art document information.

          However, in the conventional oscillating wet etching apparatus, the temperature slightly decreases as the etchant (etching solution) approaches the liquid surface, and the speed of the upward flow of the etchant is reduced, so that a plurality of wafers are removed. When arranged in a vertical wafer cartridge, there is a problem that a difference in etching amount occurs in the vertical direction within the wafer surface.

          In addition, since the etchant is stirred by a single screw fan and the upward flow of the etchant is created, the speed of the upward flow becomes non-uniform, resulting in a difference in etching amount in the left-right direction within the wafer surface. was there.

          The present invention has been made under the technical background as described above. Accordingly, an object of the present invention is to provide a wet etching apparatus for a piezoelectric wafer.

          In order to achieve the above object, the present invention provides a piezoelectric wafer wet etching apparatus having a screw fan that stirs an etchant and a heater that heats the etchant, and a barrel that rotates about a revolution axis provided in a horizontal direction. And a wafer accommodating portion for accommodating a piezoelectric wafer that rotates around an axis of rotation provided in the barrel.

          Further, the present invention is characterized by having a plate part that holds the end of the revolution shaft at the left and right sides of the barrel and divides the inside of the wet etching tank.

          Moreover, the screw fan which stirs an etchant is each arrange | positioned in the wet etching tank except the part which is divided by the board part and a barrel is arrange | positioned, It is characterized by the above-mentioned.

          The wet etching apparatus for a piezoelectric wafer according to the present invention can significantly reduce the in-wafer variation in the etching amount of a wafer to be processed. As a result, each crystal formed on one crystal wafer can be reduced. In the case where the etching process of individual crystal units is further performed on the wet etching surface of the resonator in a later process, the load of the etching process can be remarkably reduced. Can be manufactured.

          Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol in each figure shall show the same object.

          FIG. 1 is a schematic view of a wet etching apparatus 2 for a piezoelectric wafer 1 made of quartz according to the present invention as seen from the front. That is, a barrel 4 that rotates about the revolution shaft 3 provided in the horizontal direction is provided at the center of the etching tank, and a large number of piezoelectric materials that rotate about the rotation shaft 5 provided in the barrel 4 as an axis. There is a wafer accommodating portion 6 that accommodates the body wafer 1, a plate portion 8 that holds the revolution shaft end 7 on the left and right sides with the above-described barrel 4 sandwiched therebetween, and divides the inside of the wet etching tank, is arranged in the vertical direction, and the etchant 9 is The apparatus has a plurality of screw fans 10 for stirring, and has a heater 11 at the bottom of the tank and a lid 12 made of a transparent material such as acrylic, which can observe the internal state, at the top of the apparatus 2. Since the plate portion 8, the screw fan 10, and the heater 11 are arranged symmetrically in the left-right direction around the barrel 4, the flow of the etchant 9 in the tank formed by the screw fan 10 and the heater 11, Since the barrel 4 itself rotates about the revolution axis 3, and at the same time, the wafer accommodating portion 6 provided in the barrel 4 rotates as the axis of the rotation axis 5, the etchant 9 corresponding to the wafer 1 in the vertical and horizontal directions. Variation in the flow rate is suppressed, and the effect of performing uniform etching of the wafer 1 is achieved. Only the rotating barrel 4 is likely to etch only the outer peripheral portion of the wafer 1 accommodated in the barrel 4, but in the wet etching apparatus 2 of the present invention, since the wafer accommodating portion 6 in the barrel 4 also rotates, Also here, the effect of performing uniform etching of the wafer 1 is achieved.

          FIG. 2 is a schematic conceptual view showing the operation mechanism of the barrel 4 used in the wet etching apparatus 2 of the piezoelectric wafer 1 according to the present invention as seen from the axial direction of the revolution shaft 3 and the rotation shaft 5. In this figure, there are two rotating shafts 5 and two wafer accommodating portions 6 are arranged on each rotating shaft 5. However, the present invention is not limited to this, and for example, there are four rotating shafts 5, and more Needless to say, the wafer containing portion 6 may be included, and these cases are also included in the technical scope of the present invention. When the ratio of rotation to revolution was approximately 11 (rotation): 30 (revolution), good results with little difference in etching amount were obtained.

          FIG. 3 is a schematic diagram of a conventional oscillating wet etching apparatus as seen from the front. In this conventional oscillating wet etching apparatus, the temperature of the etchant 9 (etching solution) approaches a liquid surface, the temperature of the etchant 9 slightly decreases, and the flow rate of the etchant 9 is weakened. When the body wafer 1 is placed in a vertical wafer cartridge (container), there is a problem that the etching amount is different in the vertical direction within the surface of the piezoelectric wafer 1, and the etchant 9 is stirred by one screw fan 10 However, since the upward flow of the etchant 9 was made, the speed of the upward flow became non-uniform, and as a result, there was a problem that a difference in etching amount occurred in the left-right direction within the surface of the piezoelectric wafer 1. For example, when processing was performed aiming at etching of 68 μm, a difference in etching amount of 1 μm at maximum occurred.

It is the schematic model which looked at the wet etching apparatus of the piezoelectric material wafer of this invention from the front direction. It is a general | schematic schematic diagram seen from the axial direction of the revolution axis | shaft which shows the operation mechanism of the barrel used for the wet etching apparatus of the piezoelectric material wafer of this invention, and a rotating shaft. It is the schematic model which looked at the conventional rocking | fluctuation type wet etching apparatus from the front direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piezoelectric wafer 2 Wet etching apparatus 3 Revolving shaft 4 Barrel 5 Rotating shaft 6 Wafer accommodating part 7 Revolving shaft end 8 Plate part 9 Etchant 10 Screw fan 11 Heater 12 Cover part

Claims (3)

In a wet etching apparatus for a piezoelectric wafer having a screw fan for stirring an etchant and a heater for heating the etchant,
A barrel that rotates around a horizontal axis of revolution,
A wafer accommodating portion for accommodating a piezoelectric wafer that rotates about an axis of rotation provided in the barrel ;
A wet etching apparatus for a piezoelectric wafer, comprising:
2. The wet etching apparatus for a piezoelectric wafer according to claim 1, further comprising a plate portion that sandwiches the barrel and holds the end of the revolving shaft on the right and left sides and divides the inside of the wet etching tank.

3. The piezoelectric wafer according to claim 2, wherein the screw fan for stirring the etchant is disposed in each of the wet etching tanks except for a portion partitioned by the plate portion and where the barrel is disposed. Wet etching equipment.

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