JP6240531B2 - Method for manufacturing piezoelectric vibrator - Google Patents

Description

  The present invention relates to a method for manufacturing a piezoelectric vibrator used in an oscillation circuit such as a mobile phone.

  Piezoelectric vibrators are made of a piezoelectric material such as quartz, and rectangular thickness-slip quartz vibrators or tuning-fork crystal vibrators that are flexibly vibrated with a plurality of vibrating arms are used according to the oscillation frequency. FIG. 1 is a schematic view of a tuning fork type crystal resonator. The tuning fork type crystal resonator 1 includes two vibrating arms 2 and a tuning fork base 3, excitation electrodes 4 are formed on the front and back surfaces and side surfaces of the vibrating arm 2, and a mount pad 5 is formed on the tuning fork base 3. By applying a voltage to the excitation electrode 4, an electric field is generated, causing bending vibration. As a technique for forming an electrode pattern of a piezoelectric vibrator, a technique using photolithography is known.

  A piezoelectric vibrator formed on a wafer made of a piezoelectric material is connected to a wafer frame via a connecting portion, and a measurement pad for measuring characteristics and adjusting a frequency of the piezoelectric vibrator is formed on the frame. ing.

  When wet etching a piezoelectric material such as quartz, the etching rate differs for each crystal plane and anisotropic etching is performed. Therefore, an inclined surface is formed at the fork formed at the base of the vibrating arm. As described above, there has been proposed a method in which exposure is performed by inclining a light source so as to approach a direction in which irradiation light is irradiated perpendicularly to the fork.

JP 2006-339729 A

  Conventionally, when performing characteristic measurement and frequency adjustment of a piezoelectric vibrator in a wafer state, probing has been performed using an element mounting pad. However, as the element becomes smaller, the probe pitch becomes narrower and the probe position becomes smaller. High accuracy is required, and probing with mount pads is becoming difficult. Therefore, in a small piezoelectric vibrator, it is necessary to form a measurement pad on the wafer frame so that the pad can be enlarged. However, if the metal film on the side surface of the frame is not accurately patterned, When a plurality of elements oscillate simultaneously due to conduction between adjacent elements and electrodes, there is a problem that frequency interference occurs, and an accurate oscillation frequency cannot be measured.

  An object of the present invention is to provide a method of manufacturing a piezoelectric vibrator that is not affected by adjacent elements in measurement in a wafer state without increasing the number of production steps.

At least a mask layer patterning step for forming a mask layer of a desired shape on the piezoelectric wafer, and etching the piezoelectric wafer on which the mask layer is formed to form a piezoelectric vibrating piece substrate having a plurality of piezoelectric vibrating pieces connected to each other. The piezoelectric vibrating reed substrate forming step and the electrode forming step of forming electrodes on a plurality of piezoelectric vibrating reeds connected to the piezoelectric vibrating reed substrate, and simultaneously oscillating adjacent piezoelectric vibrating reeds formed on the piezoelectric vibrating reed substrate A method of manufacturing a piezoelectric vibrator including either a measurement process or a frequency adjustment process, wherein in the piezoelectric substrate forming process, a piezoelectric vibrating piece having an outer shape of a piezoelectric vibrating piece and a frame for supporting the piezoelectric vibrating piece If, to form a piezoelectric wafer connecting portion is formed for connecting the base and the frame of the piezoelectric vibrating piece, the electrode forming step, full to at least one principal surface of the piezoelectric wafer Tilting the light source used in the preparative lithography, the piezoelectric vibrating piece irradiation light from the light source, the frame, the principal surface of the connecting portion and, as corresponding to the side surface of the frame facing the side surface of the base of at least connecting portions allow connection piezoelectric vibrating reed A method for manufacturing a piezoelectric vibrator that irradiates the laser beam .

  A method for manufacturing a piezoelectric vibrator in which the piezoelectric vibrator is a tuning fork type crystal vibrator or a thickness-sliding crystal vibrator.

  According to the method of the present invention, it is possible to provide a method for manufacturing a piezoelectric vibrator that is not affected by adjacent elements in measurement in a wafer state without increasing the number of production steps.

Schematic diagram of tuning fork crystal unit Top view of piezoelectric vibrating piece substrate Schematic explaining the exposure process in the present invention

  An embodiment of the present invention will be described with reference to the drawings, taking a tuning fork type crystal resonator as an example.

  First, in the mask layer patterning step, a photoresist is applied after forming a corrosion resistant film made of, for example, Au / Cr on the front and back of the piezoelectric wafer. Next, exposure and development are performed using a photomask corresponding to the shape of the tuning fork crystal unit. Thereafter, the Au film and the Cr film are etched to form a mask layer corresponding to the outer shape of the tuning fork crystal unit.

  Next, in the piezoelectric vibrating reed substrate forming step, the piezoelectric wafer on which the mask layer is formed is etched with an etchant such as hydrofluoric acid, ammonium fluoride, buffered hydrofluoric acid, and then the unnecessary photoresist and corrosion resistant film are peeled off. Thus, as shown in FIG. 2, a piezoelectric vibrating reed substrate in which a plurality of piezoelectric vibrating reeds are connected is formed. The tuning fork type crystal resonator 1 is connected to the frame 6 of the piezoelectric vibrating piece substrate 9 through a connecting portion 7.

  Next, in the electrode forming step, a metal film made of, for example, Au / Cr is formed on the piezoelectric vibrating piece substrate 9 in a state where a plurality of tuning fork type crystal resonators 1 are connected, and then a photoresist is formed on the metal film. Then, as shown in FIG. 3, the light source 10 is tilted through an electrode pattern for wiring on the tuning fork type crystal resonator 1 and a photomask (not shown) corresponding to the measurement pad. Then, exposure is performed so that the irradiation light strikes the wafer obliquely, and development is performed to form a photoresist pattern. Next, using the photoresist pattern as a mask, the exposed metal film is removed by etching, and the remaining photoresist is peeled off, so that the tuning fork crystal unit 1 is provided with electrode patterns such as the excitation electrode 4 and the mount pad 5. Then, a measurement pad 8 is formed on the frame 6. In this way, by tilting the light source 10 on the side surface of the frame 6 and applying irradiation light, the measurement pad 8 can be reliably electrically separated from the measurement pad 8 of the adjacent element.

  In the piezoelectric vibrating reed substrate manufactured by the above steps, accurate oscillation is not affected by adjacent elements such as frequency interference when simultaneously oscillating adjacent piezoelectric vibrating reeds in the characteristic measurement step or frequency adjustment step. The frequency can be measured.

  In this embodiment, the tuning fork type crystal resonator is taken as an example. However, the present invention is not limited to this, and the present invention can be similarly applied to the case where the thickness shear resonator is formed on the wafer by photolithography.

1 tuning fork type crystal resonator 2 vibrating arm 3 tuning fork base 4 excitation electrode 5 mount pad 6 frame 7 connecting part 8 measuring pad 9 piezoelectric vibrating piece substrate 10 light source

Claims (2)

At least, a mask layer patterning step of forming a mask layer having a desired shape on the piezoelectric wafer, by etching the piezoelectric wafer formed with the mask layer, the piezoelectric resonator element substrate having a plurality of piezoelectric vibrating pieces facilities linked a piezoelectric vibrating piece substrate forming step of forming, said and an electrode forming step of forming a plurality of the piezoelectric vibrating electrode on a piece for connecting the piezoelectric resonator element substrate, the piezoelectric vibrating adjacent formed on the piezoelectric vibrating piece substrate A method of manufacturing a piezoelectric vibrator including either a characteristic measuring step for simultaneously oscillating pieces or a frequency adjusting step, wherein in the piezoelectric substrate forming step, the piezoelectric vibrating piece having an outer shape of a piezoelectric vibrating piece; forming a frame for supporting the piezoelectric resonator element, the piezoelectric wafer on which connecting portion is formed for connecting the said frame with the base of the piezoelectric vibrating reed, wherein the electrode formed The extent, the tilting the light source used in photolithography to at least one principal surface of the piezoelectric wafer, the piezoelectric vibrating piece irradiation light from the light source, the frame, the main surface and, at least the connection of the connecting portion A method of manufacturing a piezoelectric vibrator , comprising: irradiating a side surface of the frame facing a side surface of a base portion of the piezoelectric vibrating piece connectable to a portion .   The method of manufacturing a piezoelectric vibrator, wherein the piezoelectric vibrator according to claim 1 is a tuning fork type crystal vibrator or a thickness-shearing crystal vibrator.

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