Crystal oscillator and method of manufacturing the same

Abstract

The present application relates to a crystal oscillator and a method for manufacturing the same. The crystal oscillator includes a thinned piezoelectric substrate, a first electrode, a second electrode, and a support frame. The thinned piezoelectric substrate has a first surface and a second surface opposite to each other. The first electrode includes a first electrode portion on the first surface and a first extension electrode portion extending from the first electrode portion to the second surface. The second electrode is on the second surface and includes a second electrode portion and a second extension electrode portion extending from the second electrode portion. The support frame is disposed on the second surface. The support frame is used to support the thinned piezoelectric substrate, and the support frame is made of a photoresist material. Therefore, the structure shape of the support frame can be controlled by a manufacturing process, so that the thickness, width and shape of the support frame can be accurately controlled.

Description

Technical Field

[0001] This invention relates to an oscillator and its manufacturing method, and particularly to a crystal oscillator with a high oscillation frequency and its manufacturing method. Background Technology

[0002] Quartz crystal is a type of ceramic piezoelectric material, often used to make crystal oscillators with high oscillation frequencies, and can be applied in various electronic products.

[0003] Existing crystal oscillators generally include an oscillating substrate made of quartz crystal and two electrodes formed on opposite surfaces of the oscillating substrate for external electrical connection. The thinner the quartz crystal, the higher the oscillation frequency it can generate. Therefore, the industry typically uses thinning methods to achieve the required oscillation frequency with the thickness of the oscillating substrate. To avoid insufficient strength of the thinned oscillating substrate, which could be unable to withstand external forces and potentially cause damage in subsequent processes, the industry often chooses to locally thin the substrate, forming a thicker frame of the same material around the oscillating substrate. This frame serves as a clamping or connection area for connecting to other electronic components and increases the mechanical support of the thinned oscillating substrate.

[0004] For example, Japanese Patent No. JP2014154994A discloses a vibration element whose substrate has a flat vibrating part and a thick wall part (equivalent to a frame) integrated with the vibrating part. The thick wall part can not only enhance the support of the vibration element, but also achieve a default vibration frequency by controlling the overall thickness of the substrate.

[0005] However, when the oscillating substrate has a locally thicker frame, the electrodes need to cross the frame during the manufacturing process. Therefore, the electrode yield is easily reduced due to the height difference, which in turn affects the overall properties of the crystal oscillator. Summary of the Invention

[0006] The purpose of this invention is to provide a method for manufacturing a lightweight crystal oscillator.

[0007] The method for manufacturing a crystal oscillator according to the present invention includes a first electrode forming step, a thinning step, a second electrode forming step, a first extended electrode forming step, and a support frame forming step.

[0008] The first electrode part forming step forms a first electrode part on one surface of a piezoelectric substrate having a predetermined thickness, thereby obtaining a semi-finished product.

[0009] The thinning step involves comprehensively thinning the piezoelectric substrate of the semi-finished product to obtain a thinned piezoelectric substrate with a thickness less than that of the piezoelectric substrate.

[0010] The second electrode forming step forms a second electrode on the surface of the thinned piezoelectric substrate opposite to the first electrode portion. The second electrode has a second electrode portion corresponding to the first electrode portion and a second extended electrode portion extending from the second electrode portion to the periphery of the thinned piezoelectric substrate.

[0011] The first extended electrode forming step forms a first extended electrode portion that extends from the first electrode portion and along the side peripheral surface of the thinned piezoelectric substrate to the surface of the thinned piezoelectric substrate on which the second electrode is formed.

[0012] The support frame forming step involves forming a support frame on the surface of the thinned piezoelectric substrate on which the second electrode is formed using a photoresist material, such that the second electrode portion is located inside the support frame, and at least a portion of the second extended electrode portion is located outside the support frame.

[0013] Preferably, the method for manufacturing a crystal oscillator according to the present invention further includes a bonding step performed before the thinning step, wherein the semi-finished product is bonded to the temporary substrate with the first electrode portion facing the temporary substrate.

[0014] Preferably, the method for manufacturing a crystal oscillator according to the present invention further includes a removal step performed after the support frame formation step, wherein the temporary substrate is removed from the thinned piezoelectric substrate.

[0015] Preferably, in the method for manufacturing a crystal oscillator according to the present invention, the photoresist material used in the support frame forming step is selected from positive photoresist material or negative photoresist material.

[0016] Preferably, in the method for manufacturing a crystal oscillator according to the present invention, the first electrode portion and the second electrode are formed by deposition or printing of conductive materials, the first extended electrode portion is formed by printing or plating of conductive materials, and the materials of the first electrode portion, the first extended electrode portion and the second electrode are respectively selected from gold, silver or aluminum, and may be the same or different from each other.

[0017] Another object of the present invention is to provide a crystal oscillator.

[0018] The crystal oscillator of the present invention includes a thinned piezoelectric substrate, a first electrode, a second electrode, and a support frame.

[0019] The thinned piezoelectric substrate has the same thickness and includes a first surface and a second surface that are opposite to each other.

[0020] The first electrode includes a first electrode portion located on the first surface of the thinned piezoelectric substrate, and a first extended electrode portion extending from the first electrode portion and along the side peripheral surface of the thinned piezoelectric substrate to the second surface.

[0021] The second electrode is located on the second surface of the thinned piezoelectric substrate, including a second electrode portion that at least partially overlaps with the orthographic projection range of the first electrode portion, and a second extended electrode portion that extends from the second electrode portion to the same side as the first extended electrode portion.

[0022] The support frame is made of photoresist material and is located on the second surface of the thinned piezoelectric substrate. The second electrode portion is located within the support frame, and at least a portion of the second extended electrode portion is located outside the support frame.

[0023] Preferably, in the crystal oscillator of the present invention, the thickness of the support frame is between 10 μm and 100 μm.

[0024] Preferably, in the crystal oscillator of the present invention, the support frame is at least partially spaced from the edge of the thinned piezoelectric substrate, and at least one edge region is defined on the second surface located around the support frame, wherein the first extended electrode portion and the second extended electrode portion are located in the edge region of the second surface.

[0025] Preferably, in the crystal oscillator of the present invention, the support frame has a hollow annular structure, the second electrode portion is located within the frame of the support frame, and the second extended electrode portion extends from the second electrode portion and passes between the support frame and the thinned piezoelectric substrate to be located in the edge region.

[0026] The beneficial effects of this invention are as follows: by using photoresist as the constituent material of the support frame of the oscillator, the thickness and shape of the photoresist can be controlled by the photolithography process, thereby precisely controlling the width, shape and distribution position of the support frame, and thus precisely controlling the overall thickness of the crystal oscillator, so that the crystal oscillator has a high oscillation frequency as expected. Attached Figure Description

[0027] Figure 1 This is a top view schematic diagram illustrating an embodiment of the crystal oscillator of the present invention;

[0028] Figure 2 This is a side sectional view, used to illustrate the following: Figure 1 The cross-sectional structure of the II-II section line;

[0029] Figure 3 This is a side sectional view, used to illustrate the following: Figure 1 The cross-sectional structure of the III-III section line;

[0030] Figure 4 This is a flowchart illustrating the fabrication method of the crystal oscillator.

[0031] Figure 5 This is a side view diagram, for reference. Figure 4 The manufacturing method of the embodiments described herein; and

[0032] Figure 6 This is a side view diagram, continuing... Figure 5 The manufacturing method of the embodiments described herein is explained. Detailed Implementation

[0033] Before the present invention is described in detail, it should be noted that similar elements are represented by the same numbers in the following description. The relevant technical content, features, and effects of the present invention will be clearly presented in the following detailed description of embodiments with reference to the accompanying drawings. Furthermore, it should be noted that the accompanying drawings are only for illustrating the structural and / or positional relationships between elements and are not related to the actual dimensions of each element, and should not be considered as limiting conditions of the present invention in any way.

[0034] See Figure 1 and Figure 2 An embodiment of the crystal oscillator 200 of the present invention includes a thinned piezoelectric substrate 2, a first electrode 3, a second electrode 4, and a support frame 5.

[0035] The thinned piezoelectric substrate 2 has a uniform thickness and includes a first surface 21 and a second surface 22 that are opposite to each other. In this embodiment, the thinned piezoelectric substrate 2 is made of quartz crystal and has a thickness of no more than 50 μm. Preferably, the thickness of the thinned piezoelectric substrate 2 is no more than 10 μm.

[0036] The first electrode 3 includes a first electrode portion 31 located on the first surface 21 of the thinned piezoelectric substrate 2, and a first extended electrode portion 32 extending from the first electrode portion 31 and along the side peripheral surface of the thinned piezoelectric substrate 2 to the second surface 22.

[0037] See also Figure 3 The second electrode 4 is located on the second surface 22 of the thinned piezoelectric substrate 2, including a second electrode portion 41 that at least partially overlaps with the orthographic projection range of the first electrode portion 31, and a second extended electrode portion 42 that extends from the second electrode portion 41 to the same side as the first extended electrode portion 32.

[0038] The first electrode 3 and the second electrode 4 are made of conductive materials selected from gold, silver or aluminum, and may be the same or different from each other.

[0039] The support frame 5 is made of photoresist material and is located on the second surface 22 of the thinned piezoelectric substrate 2. The photoresist material can be selected from positive or negative photoresist materials, and its thickness is between 10 μm and 100 μm.

[0040] In this embodiment, the support frame 5 surrounds the second electrode portion 41 and is at least partially spaced from the periphery of the thinned piezoelectric substrate 2, while at least one edge region 23 located on the periphery of the support frame 5 is defined on the second surface 22 (see...). Figure 2 The second extended electrode portion 42 extends from the second electrode portion 41 and passes under the support frame 5 to the edge region 23, such that at least a portion of the second extended electrode portion 42 is located outside the support frame 5. The first extended electrode portion 32 extends from the first surface 21 to the edge region 23 of the second surface 22. Since the first extended electrode portion 32 and the second extended electrode portion 42 are formed on the same surface, it is more conducive to external electrical connection, which helps the crystal oscillator 200 to be configured in electronic products in subsequent applications.

[0041] It should be noted that the support frame 5 described in this embodiment is illustrated using a hollow ring structure as an example. However, in actual implementation, the width, shape, and position of the support frame 5 may vary depending on the requirements or design. For example, the support frame 5 may also be a single or multiple strip structures formed only on opposite sides, or a non-closed ring-like structure, as long as it can be used to increase the thickness and provide a clamping position.

[0042] The method for manufacturing the crystal oscillator 200 described in the foregoing embodiment is as follows:

[0043] See Figure 4 , Figure 5 and Figure 6 The manufacturing method sequentially includes a first electrode forming step 81, a bonding step 82, a thinning step 83, a second electrode forming step 84, a first extended electrode forming step 85, a support frame forming step 86, and a removal step 87.

[0044] The first electrode part forming step 81 involves forming the first electrode part 31 on one surface of a piezoelectric substrate 20 made of quartz and having a predetermined thickness by deposition or printing of conductive material, thereby obtaining a semi-finished product 300.

[0045] The bonding step 82 involves bonding the semi-finished product 300 to the temporary substrate 6 with the first electrode portion 31 facing the temporary substrate 6. The temporary substrate 6 may be made of materials such as glass, acrylic, or ceramic, and is used to provide support strength to prevent the piezoelectric substrate 2 from breaking due to insufficient mechanical strength during subsequent processes, such as the thinning step 83.

[0046] The thinning step 83 involves thinning the piezoelectric substrate 20 of the semi-finished product 300 entirely by grinding or chemical etching to obtain a thinned piezoelectric substrate 2 with a thickness less than that of the piezoelectric substrate 20. It should be noted that the thickness of the thinned piezoelectric substrate 2 can be determined according to the desired oscillation frequency, and the thinned piezoelectric substrate 2 has a uniform thickness throughout. Preferably, the thickness of the thinned piezoelectric substrate 2 is no greater than 50 μm. When used in a high-frequency oscillator, the thickness of the thinned piezoelectric substrate 2 is no greater than 10 μm.

[0047] The second electrode formation step 84 involves forming a second electrode portion 41, located corresponding to the first electrode portion 31, and a second extended electrode portion 42 extending from the second electrode portion 41 to the periphery of the thinned piezoelectric substrate 2, on the surface of the thinned piezoelectric substrate 2 opposite to the first electrode portion 31, using conductive material by deposition or printing, to form the second electrode 4. The orthographic projection range of the second electrode portion 41 at least partially overlaps with that of the first electrode portion 31.

[0048] The first extended electrode forming step 85 involves forming the first extended electrode portion 32 on the first surface 21 by printing or coating conductive material, and then forming a portion that extends from the first electrode portion 31 and along the side peripheral surface of the thinned piezoelectric substrate 2 to the second surface 22 of the thinned piezoelectric substrate 2, so that the first extended electrode portion 32 and the second extended electrode portion 42 can be located on the same surface.

[0049] In some embodiments, the first extended electrode forming step 85 may first form the first extended electrode portion 32 on the second surface 22, and then use a conductive material (e.g., silver paste) to connect the first electrode portion 31 and the first extended electrode portion 32 via the side peripheral surface of the thinned piezoelectric substrate 2.

[0050] It should be noted that in some embodiments, the order of implementation of the second electrode forming step 84 and the first extended electrode forming step 85 may be adjusted according to process requirements. That is, the first extended electrode forming step 85 may be implemented first and then the second electrode forming step 84 may be performed.

[0051] The support frame forming step 86 involves coating a positive or negative photoresist material onto the second surface 22 of the thinned piezoelectric substrate 2, and forming a photoresist layer 7 of a predetermined thickness on the second surface 22 (see...). Figure 6 Then, a portion of the structure of the photoresist layer 7 is removed using photolithography to form the support frame 5 with a predetermined shape on the surface of the thinned piezoelectric substrate 2.

[0052] In detail, this invention utilizes photoresist as the constituent material of the support frame 5. Therefore, by adjusting the parameters of the coating process and the shielding pattern in the photolithography process, the thickness, width, shape, and distribution position of the subsequently fabricated support frame 5 can be precisely controlled to meet design requirements. It should be noted that the relevant process details and condition parameters of the coating and photolithography processes, such as film thickness, exposure wavelength, intensity, and time, or the formation method of the shielding pattern, will vary depending on the choice of different photoresist materials. Furthermore, the relevant process details and condition parameters are known in the relevant art and will not be elaborated upon here.

[0053] Finally, by performing the removal step 87, the temporary substrate 6 is removed from the thinned piezoelectric substrate 2, thus obtaining the desired result. Figure 1 The crystal oscillator 200 is shown. The removal step 87 can select a corresponding removal method depending on the bonding method between the temporary substrate 6 and the semi-finished product 300. For example, when the semi-finished product 300 and the temporary substrate 6 are bonded using photolytic adhesive or thermal adhesive, the removal step 87 removes the temporary substrate 6 by means of light or heat.

[0054] In summary, the method for manufacturing the crystal oscillator 200 of the present invention utilizes photoresist as the constituent material of the support frame 5. By adjusting the coating process and shielding pattern, the thickness, width, shape, and distribution position of the support frame 5 can be precisely controlled. The process is simple and easy to control, thereby enabling control over the overall thickness of the crystal oscillator 200 (including the thinned piezoelectric substrate 2 and the support frame 5), so that the crystal oscillator 200 has the expected high oscillation frequency. Therefore, the objective 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. Any person skilled in the art 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 determined by the scope defined in the claims of this application.

Claims

1. A method for manufacturing a crystal oscillator, characterized in that, Include: In the first electrode part forming step, a first electrode part is formed on one surface of a piezoelectric substrate having a predetermined thickness to obtain a semi-finished product; The thinning step involves comprehensively thinning the piezoelectric substrate of the semi-finished product to obtain a thinned piezoelectric substrate with a thickness less than that of the piezoelectric substrate. In the second electrode forming step, a second electrode is formed on the surface of the thinned piezoelectric substrate opposite to the first electrode portion. The second electrode has a second electrode portion corresponding to the first electrode portion and a second extended electrode portion extending from the second electrode portion to the periphery of the thinned piezoelectric substrate. The first extended electrode forming step involves forming a first extended electrode portion that extends from the first electrode portion and along the side peripheral surface of the thinned piezoelectric substrate to the surface of the thinned piezoelectric substrate on which the second electrode is formed. and The support frame forming step involves forming a support frame on the surface of the thinned piezoelectric substrate on which the second electrode is formed using a photoresist material, such that the second electrode portion is located inside the support frame, and at least a portion of the second extended electrode portion is located outside the support frame.

2. The method for manufacturing a crystal oscillator according to claim 1, characterized in that, It also includes a bonding step performed before the thinning step, the bonding step being used to bond the semi-finished product to the temporary substrate with the first electrode portion facing the temporary substrate.

3. The method for manufacturing a crystal oscillator according to claim 2, characterized in that, It also includes a removal step performed after the support frame formation step, the removal step being used to remove the temporary substrate from the thinned piezoelectric substrate.

4. The method for manufacturing a crystal oscillator according to claim 1, characterized in that, The photoresist material used in the support frame formation step is selected from positive photoresist materials or negative photoresist materials.

5. The method for manufacturing a crystal oscillator according to claim 1, characterized in that, The first electrode portion and the second electrode are formed by deposition or printing of conductive materials, and the first extended electrode portion is formed by printing or plating of conductive materials. The materials of the first electrode portion, the first extended electrode portion and the second electrode are selected from gold, silver or aluminum, and may be the same or different from each other.

6. A crystal oscillator, characterized in that, Include: A thin piezoelectric substrate having the same thickness includes a first surface and a second surface that are opposite to each other; The first electrode includes a first electrode portion located on the first surface of the thinned piezoelectric substrate, and a first extended electrode portion extending from the first electrode portion and along the side peripheral surface of the thinned piezoelectric substrate to the second surface. The second electrode is located on the second surface of the thinned piezoelectric substrate and includes a second electrode portion that at least partially overlaps with the orthographic projection range of the first electrode 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 A support frame, made of photoresist material, is located on the second surface of the thinned piezoelectric substrate, the second electrode portion is located within the range of the support frame, and at least a portion of the second extended electrode portion is located outside the support frame.

7. The crystal oscillator according to claim 6, characterized in that, The thickness of the support frame is between 10 μm and 100 μm.

8. The crystal oscillator according to claim 6, characterized in that, The support frame is at least partially spaced from the edge of the thinned piezoelectric substrate, and at least one edge region is defined on the second surface located around the support frame, with the first extended electrode portion and the second extended electrode portion located in the edge region of the second surface.

9. The crystal oscillator according to claim 8, characterized in that, The support frame has a hollow ring structure, the second electrode portion is located within the frame of the support frame, and the second extended electrode portion extends from the second electrode portion and passes between the support frame and the thinned piezoelectric substrate to be located in the edge region.

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