Crystal oscillator and manufacturing method thereof

Abstract

The present invention relates to a crystal oscillator and a manufacturing method thereof, wherein the crystal oscillator comprises an oscillation substrate, a hollow frame, a first electrode and a second electrode. The oscillation substrate comprises a first surface, a second surface and an oscillation portion that are opposite to each other. The hollow frame is arranged on the second surface and frames the oscillation portion, and the oscillation portion is defined by a main oscillation region and a thinned region having a thickness less than that of the main oscillation region. The first electrode comprises a first electrode portion located on the first surface and a first extended electrode portion extending from the first electrode portion to the second surface. The second electrode is located on the second surface and comprises a second electrode portion located on the oscillation portion and a second extended electrode portion extending from the second electrode portion to the same side as the first extended electrode portion.

Description

Technical Field

[0001] The present invention relates to an oscillator and a manufacturing method thereof, and in particular to a crystal oscillator with a high oscillation frequency and a manufacturing method thereof. Background Art

[0002] The structure of an existing crystal oscillator generally includes a vibration plate composed of a quartz crystal, and two electrodes formed on two opposite surfaces of the vibration plate and used for external electrical connection. According to industry demand, crystal oscillators are gradually developing in the direction of lightweight and thinning. By reducing the thickness of the vibration plate to generate a higher oscillation frequency, it is helpful to be applied in the field of high-frequency communications. For example, Japanese invention patent No. JP2014154994A discloses a vibration element, which uses a local thinning method to make the substrate of the vibration element have a flat vibration part and a thick wall part that is integrated with the vibration part and has a thicker thickness. The default vibration frequency is achieved by controlling the overall thickness of the substrate (i.e., the central area is thinned and the periphery is thicker), and the thick wall part is used as a part to strengthen the strength of the element and for clamping during subsequent processes, so as to avoid the problem that the vibration element is easily broken during the process due to insufficient strength of the thinned substrate.

[0003] However, the thick wall portion added to prevent the thinned substrate from breaking will also increase the weight of the entire device, which is not conducive to lightweighting of the product. Summary of the Invention

[0004] The object of the present invention is to provide a method for manufacturing a lightweight crystal oscillator.

[0005] The manufacturing method of the crystal oscillator of the present invention includes a first electrode portion manufacturing step, a bonding step, a first thinning step, a second electrode manufacturing step, an extended electrode manufacturing step, a frame forming step, and a second thinning step.

[0006] The first electrode portion manufacturing step is to form the first electrode portion on one surface of a piezoelectric substrate to obtain a first semi-finished product.

[0007] The bonding step is to bond the first semi-finished product to the temporary substrate with the first electrode portion facing the temporary substrate.

[0008] The first thinning step is to thin the entire piezoelectric substrate of the first semi-finished product to obtain a thinned piezoelectric substrate with a first thickness.

[0009] The second electrode manufacturing step is to form a second electrode on the surface of the thinned piezoelectric substrate opposite to the temporary substrate, wherein the second electrode has a second electrode portion corresponding to the first electrode portion and having at least one hole, and a second extended electrode portion extending from the second electrode portion to the periphery of the thinned piezoelectric substrate, and the orthographic projection range of the second electrode portion at least partially overlaps with the first electrode portion.

[0010] The extended electrode forming step is to form a first extended electrode portion extending from the first electrode portion and extending along the side circumference of the thinned piezoelectric substrate to the surface of the thinned piezoelectric substrate where the second electrode is formed.

[0011] The frame forming step is to form a hollow frame having a predetermined thickness on a surface of the thinned piezoelectric substrate opposite to the first electrode, surrounding the second electrode portion and being pressed onto the second extended electrode portion.

[0012] The second thinning step uses the second electrode as a shield and utilizes etching to thin the thinned piezoelectric substrate at a position located at the at least one hole to form a second semi-finished product.

[0013] Preferably, in the method for manufacturing the crystal oscillator of the present invention, the second thinning step is to completely etch away the thinned piezoelectric substrate at a position located at the at least one hole to form the second semi-finished product.

[0014] Preferably, the manufacturing method of the crystal oscillator of the present invention further comprises a removing step performed after the second thinning step, to remove the temporary substrate from the second semi-finished product.

[0015] Another object of the present invention is to provide a lightweight crystal oscillator.

[0016] The crystal oscillator of the present invention includes an oscillation substrate, a hollow frame, a first electrode, and a second electrode.

[0017] The oscillation substrate includes a first surface, a second surface and an oscillation portion that are opposite to each other. The oscillation portion is defined by a main oscillation region and a thinned region having a thickness smaller than that of the main oscillation region.

[0018] The hollow frame is disposed on the second surface of the oscillation substrate and defines the oscillation portion.

[0019] The first electrode includes a first electrode portion formed on the first surface of the oscillation substrate, and a first extension electrode portion extending from the first electrode portion and extending along a side circumference of the oscillation substrate to the second surface.

[0020] The second electrode is located on the second surface of the oscillation substrate, including a second electrode portion that at least partially overlaps with the positive projection range of the first electrode portion and is located in the oscillation portion, and a second extended electrode portion that extends from the second electrode portion to the same side as the first extended electrode portion, and the second electrode portion has at least one hole formed corresponding to the thinned area.

[0021] Preferably, the crystal oscillator described in the present invention is characterized in that at least a portion of the hollow frame is spaced apart from the edge of the oscillation substrate to form two peripheral areas spaced apart from each other and located on the same side, the first extended electrode portion is located in one of the peripheral areas, and the second extended electrode portion extends from the second electrode portion and passes between the hollow frame and the second surface to extend to the other peripheral area, and is located on the same side as the first extended electrode portion.

[0022] Preferably, in the crystal oscillator of the present invention, the thickness of the oscillation substrate located at the periphery of the hollow frame is the same as that of the main oscillation region.

[0023] Preferably, in the crystal oscillator of the present invention, at least a portion of the thinned region is a through hole passing through the oscillating portion.

[0024] The beneficial effect of the present invention is that the second electrode is used as a shield, and the area of the oscillation part of the oscillation substrate where the electrode is not formed can be thinned by etching, so that the oscillation part as a whole has two different thicknesses and is thinner, which can enable the crystal oscillator to have an expected oscillation frequency while further reducing the overall weight of the crystal oscillator. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic top view illustrating an embodiment of a crystal oscillator of the present invention;

[0026] Figure 2 This is a side sectional view, which helps to illustrate the Figure 1 The cross-sectional structure of the II-II cutting line;

[0027] Figure 3 This is a side sectional view, which helps to illustrate the Figure 1 The cross-sectional structure of the III-III cutting line;

[0028] Figure 4 is a flow chart illustrating a method for making the crystal oscillator;

[0029] Figure 5 It is a side view diagram, auxiliary Figure 4 Describe the method of making the embodiment; and

[0030] Figure 6It is a side view diagram, continued Figure 5 The manufacturing method of the embodiment will be described. DETAILED DESCRIPTION

[0031] Before describing the present invention in detail, it should be noted that similar components are numbered the same throughout the following description. The relevant technical content, features, and functions of the present invention will be more clearly presented in the following detailed description of the embodiments with reference to the accompanying drawings. Furthermore, it should be noted that the drawings of the present invention merely illustrate the relative structural and / or positional relationships between components and are not related to the actual dimensions of the components. They should not be construed as limiting the present invention in any way.

[0032] See Figure 1 、 Figure 2 and Figure 3 An embodiment of the crystal oscillator 200 of the present invention includes an oscillation substrate 2, a hollow frame 3, a first electrode 4 and a second electrode 5.

[0033] The oscillation substrate 2 includes a first surface 21, a second surface 22 and an oscillation portion 23 opposite to each other. The oscillation portion 23 is formed by a hollow frame 3 provided on the second surface 22 (see FIG. Figure 1 ), and is defined by a main oscillation region 231 having a first thickness T1 and a thinned region 232 having a second thickness T2, wherein the second thickness T2 is less than the first thickness T1. The oscillation substrate 2 is made of a resonant piezoelectric material, selected from quartz crystal. In this embodiment, the first thickness T1 of the main oscillation region 231 is no greater than 50 μm, and the second thickness T2 of the thinned region 232 is no greater than 10 μm.

[0034] In some embodiments, at least a portion of the thinned region 232 forms a through hole 2321 (see FIG. Figure 2 ), thereby reducing the overall weight of the crystal oscillator 200. Preferably, the second thickness T2 of the thinned region 232 is 0, that is, the thinned region 232 is entirely formed by the through hole 2321 penetrating the oscillation substrate 2.

[0035] The hollow frame 3 is disposed on the second surface 22 of the oscillating substrate 2 and defines the oscillating portion 23. This increases the thickness of the hollow frame 3 to provide a clamping position, thereby facilitating its placement within the electronic component. The hollow frame 3 can be made of either an insulating material or a photoresist material, and its width, shape, and placement can vary depending on requirements and design, without specific limitations.

[0036] The first electrode 4 includes a first electrode portion 41 formed on the first surface 21 of the oscillating substrate 2, and a first extended electrode portion 42 extending from the first electrode portion 41 and along the side circumference of the oscillating substrate 2 to the second surface 22. In this embodiment, the first electrode portion 41 is formed within the projection range of the oscillating portion 23, and the first extended electrode portion 42 is located outside the hollow frame 3.

[0037] The second electrode 5 is located on the second surface 22 of the oscillation substrate 2, and includes a second electrode portion 51 located on the oscillation portion 23, and a second extended electrode portion 52 extending from the second electrode portion 51 to the same side as the first extended electrode portion 42. The orthographic projection range of the second electrode portion 51 and the first electrode portion 41 at least partially overlap, and are located within the range of the oscillation portion 23. The second electrode portion 51 has a plurality of holes 511, each corresponding to the thinned area 232. The distribution position and number of the holes 511 can vary depending on the needs, and a single hole 511 can also be formed on the second electrode portion 51, without specific limitations. The second extended electrode portion 52 extends from the second electrode portion 51 and passes between the hollow frame 3 and the second surface 22 to extend to the periphery of the hollow frame 3, and is located on the same side as the first extended electrode 42.

[0038] The first electrode 4 and the second electrode 5 are made of a conductive material selected from gold, silver, aluminum, and the like, and can be the same or different.

[0039] In this embodiment, at least a portion of the hollow frame 3 is spaced apart from the edge of the oscillating substrate 2, forming two spaced-apart peripheral regions 24 located on the same side. The first extended electrode portion 42 is located in one of the peripheral regions 24, and the second extended electrode portion 52 extends from the second electrode portion 51 and passes between the hollow frame 3 and the second surface 22 to the other peripheral region 24, located on the same side as the first extended electrode portion 42. Furthermore, the thickness of the peripheral region 24 containing the first and second extended electrode portions 42, 52, is equal to the first thickness T1 of the main oscillating region 231. This positions the first and second extended electrode portions 42, 52 at approximately the same height and on the same side of the oscillating substrate 2, facilitating external bonding to other electronic components.

[0040] The crystal oscillator 200 of the present invention can further reduce the overall weight of the crystal oscillator 200 by controlling the second thickness T2 of the thinned region 232 outside the main oscillation region 231 to be extremely thin (or forming at least a partial through hole 2321 or completely hollowing out).

[0041] See Figure 4 、 Figure 5 and Figure 6 The crystal oscillator 200 is manufactured by the following manufacturing method. The manufacturing method includes a first electrode portion manufacturing step 81, a lamination step 82, a first thinning step 83, a second electrode manufacturing step 84, an extended electrode manufacturing step 85, a frame forming step 86, a second thinning step 87, and a removal step 88.

[0042] The first electrode portion fabrication step 81 forms the first electrode portion 41 on one surface of the piezoelectric substrate 60 to obtain the first semi-finished product 300. In this embodiment, the piezoelectric substrate 60 is selected from quartz crystal, and the first electrode portion fabrication step 81 forms the first electrode portion 41 by depositing or printing a conductive material.

[0043] The bonding step 82 is to bond the first semi-finished product 300 to the temporary substrate 7 with the first electrode portion 41 facing the temporary substrate 7, which can provide support during the subsequent thinning process and electrode manufacturing process to prevent the oscillation substrate 2 from being broken during the process.

[0044] The first thinning step 83 thins the entire piezoelectric substrate 60 to obtain a thinned piezoelectric substrate 6 having a first thickness T1, wherein the first thickness T1 is smaller than the thickness of the piezoelectric substrate 60. In this embodiment, the piezoelectric substrate 60 is thinned by grinding or chemical etching to form the thinned piezoelectric substrate 6.

[0045] The second electrode forming step 84 is to form the second electrode 5 on the surface of the thinned piezoelectric substrate 6 opposite to the temporary substrate 7. Figure 1 The second electrode 5 has a second electrode portion 51 corresponding to the first electrode portion 41 and having an orthographic projection range at least partially overlapping with the first electrode portion 41, and a second extended electrode portion 52 extending from the second electrode portion 51 to the periphery of the thinned piezoelectric substrate 6, and the second electrode portion 51 is formed with a plurality of Figure 1 The hole 511 is shown such that the surface of the thinned piezoelectric substrate 6 is exposed from the hole 511. In this embodiment, the second electrode fabrication step 84 forms the second electrode 5 by depositing or printing a conductive material.

[0046] The extended electrode forming step 85 forms a first extended electrode portion 42 extending from the first electrode portion 41 and extending along the side surface of the thinned piezoelectric substrate 6 to the surface of the thinned piezoelectric substrate 6 where the second electrode 5 is formed. In this embodiment, the extended electrode forming step 85 forms the first extended electrode portion 42 by printing or plating a conductive material.

[0047] In some embodiments, the order of performing the second electrode fabrication step 84 and the extended electrode fabrication step 85 may be adjusted according to process requirements. That is, the extended electrode fabrication step 85 may be performed first and then the second electrode fabrication step 84 may be performed.

[0048] In addition, in some embodiments, during the extended electrode production step 85, the first extended electrode portion 42 can also be produced on the second surface 22 simultaneously with the second electrode extension portion 52, and then the first electrode portion 41 and the first extended electrode portion 42 are connected using silver glue to complete the production of the first electrode 4.

[0049] The frame forming step 86 is to form a hollow frame 3 having a predetermined thickness and framing the second electrode portion 51 on the surface of the thinned piezoelectric substrate 6 opposite to the first electrode portion 41, and the hollow frame 3 is pressed onto the second extended electrode portion 52. It should be noted that the frame forming step 86 is performed in different ways depending on the material constituting the hollow frame 3. For example, the hollow frame 3 can be formed by photolithography using a photoresist material. Alternatively, a hollow frame material made of an insulating material and having a predetermined shape and thickness and pre-processed can be attached to the surface of the thinned piezoelectric substrate 6 using adhesive to form the hollow frame 3.

[0050] The second thinning step 87 uses the second electrode 5 as a shield to thin the area of the thinned piezoelectric substrate 6 corresponding to the hole 511 by etching to form the second semi-finished product 400. The area subjected to the second thinning is defined as the thinned region 232. The thickness of the thinned piezoelectric substrate 6 in the area corresponding to the second electrode 5 (i.e., the main oscillation region 231) is maintained at the first thickness T1. The area of the thinned piezoelectric substrate 6 where the second electrode 5 is not formed is the thinned region 232, and the thickness of the thinned region 232 is reduced to a second thickness T2 that is less than the first thickness T1.

[0051] In some embodiments, the second thinning step 87 may further, as needed, completely etch away at least a portion of the thinned piezoelectric substrate 6 located within the hollow frame 3 where the second electrode 5 is not formed. Within the region corresponding to the thinned area 232, that is, at least a portion of the hole 511 therein, the thinning is performed to form the at least one through-hole 2321 penetrating the thinned piezoelectric substrate 6. Preferably, the thinned area 232 is completely etched away, leaving the second thickness T2 of the thinned area 232 at zero, thereby forming a completely hollow region.

[0052] The removal step 88 removes the temporary substrate 7 from the second semi-finished product 400 to obtain the crystal oscillator 200. The removal step 88 selects a corresponding removal method based on how the temporary substrate 7 was attached to the first semi-finished product 300 in the attachment step 82. For example, if the temporary substrate 7 was attached to the first semi-finished product 300 using photo- or thermal-degradable adhesive, the removal step 88 may use light or heat to decompose the adhesive and remove the temporary substrate 7.

[0053] Specifically, the manufacturing method of the present invention first forms the first electrode portion 41 and the second electrode 5 on the flat surfaces of the piezoelectric substrate 60 and the thinned piezoelectric substrate 6, respectively. Therefore, during the electrode manufacturing process, there is no need to overcome the height difference of the substrate surface. Furthermore, the thickness (first thickness T1) of the thinned piezoelectric substrate 6 is extremely thin, significantly reducing the extension height of the first extended electrode portion 42 compared to conventional crystal oscillators, thereby simplifying the manufacturing of the first electrode 4 and the second electrode 5. Subsequently, the overall thickness of the oscillation substrate 2 of the crystal oscillator 200 is adjusted using two thinning processes: the first thinning step 83 and the second thinning step 87. The main oscillation region 231, sandwiched between the first electrode portion 41 and the second electrode portion 51, is maintained at the first thickness T1, ensuring that the oscillation frequency of the crystal oscillator 200 meets expectations. At the same time, with the support of the temporary substrate 7, the second thinning step 87 directly utilizes the second electrode 5 formed on the second surface 22 as a shield, and thins the area outside the main oscillation area 231 (i.e., the surface exposed from the hole 511) to further remove part of the crystal structure, and further reduce the weight of the component when the crystal oscillator 200 has a specific oscillation frequency.

[0054] In summary, the present invention utilizes the second thinning step 87 to directly utilize the electrode as an etching shield, and removes part of the crystal structure (i.e., part of the structure of the thinned piezoelectric substrate 6) by etching to perform thinning, which can further reduce the weight of the oscillation substrate 2 and ensure that the oscillation frequency of the crystal oscillator 200 meets expectations, so the purpose of the present invention can indeed be achieved.

[0055] The above description is only a preferred embodiment of the present invention, but it is not intended to limit the scope of the present invention. Anyone familiar with this technology can make further improvements and changes on this basis without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims of this application.

Claims

1. A method for manufacturing a crystal oscillator, characterized in that: Include: a first electrode portion fabrication step of forming a first electrode portion on one surface of the piezoelectric substrate to obtain a first semi-finished product; a laminating step of laminating the first semi-finished product to the temporary substrate with the first electrode portion facing the temporary substrate; a first thinning step of thinning the entire piezoelectric substrate of the first semi-finished product to obtain a thinned piezoelectric substrate having a first thickness; a second electrode fabrication step of forming a second electrode on a surface of the thinned piezoelectric substrate opposite to the temporary substrate, the second electrode comprising a second electrode portion corresponding to the first electrode portion and having at least one hole, and a second extended electrode portion extending from the second electrode portion to a periphery of the thinned piezoelectric substrate, with an orthographic projection of the second electrode portion at least partially overlapping with the first electrode portion; an extended electrode fabrication step of forming a first extended electrode portion extending from the first electrode portion and extending along the side circumference of the thinned piezoelectric substrate to a surface of the thinned piezoelectric substrate on which the second electrode is formed; a frame forming step of forming a hollow frame having a predetermined thickness on a surface of the thinned piezoelectric substrate opposite to the first electrode, the hollow frame surrounding the second electrode portion and being pressed onto the second extended electrode portion; and In the second thinning step, the second electrode is used as a shield to thin the thinned piezoelectric substrate at a position located at the at least one hole by etching to form a second semi-finished product.

2. The method for manufacturing a crystal oscillator according to claim 1, wherein: The second thinning step is to completely etch and remove the thinned piezoelectric substrate at a position located at the at least one hole to form the second semi-finished product.

3. The method for manufacturing a crystal oscillator according to claim 1, wherein: The method further comprises a removing step performed after the second thinning step, wherein the removing step is used to remove the temporary substrate from the second semi-finished product.

4. A crystal oscillator, characterized in that: Include: An oscillating substrate comprising a first surface, a second surface and an oscillating portion opposite to each other, wherein the oscillating portion is defined by a main oscillating region and a thinned region having a thickness smaller than that of the main oscillating region; a hollow frame, disposed on the second surface of the oscillation substrate and defining the oscillation portion; A first electrode including a first electrode portion formed on the first surface of the oscillation substrate and a first extended electrode portion extending from the first electrode portion and extending along a side circumference of the oscillation substrate to the second surface; and The second electrode is located on the second surface of the oscillation substrate, including a second electrode portion that at least partially overlaps with the positive projection range of the first electrode portion and is located on the oscillation portion, and a second extended electrode portion that extends from the second electrode portion to the same side as the first extended electrode portion, and the second electrode portion has at least one hole formed corresponding to the thinned area.

5. The crystal oscillator according to claim 4, wherein: At least a portion of the hollow frame is spaced apart from the edge of the oscillation substrate to form two peripheral areas that are spaced apart from each other and located on the same side. The first extended electrode portion is located in one of the peripheral areas, and the second extended electrode portion extends from the second electrode portion and passes between the hollow frame and the second surface to extend to the other peripheral area, and is located on the same side as the first extended electrode portion.

6. The crystal oscillator according to claim 5, wherein: The thickness of the oscillation substrate located at the periphery of the hollow frame is the same as that of the main oscillation area.

7. The crystal oscillator according to claim 4, wherein: At least a portion of the thinned region is a through hole penetrating the oscillating portion.

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