Crystal oscillation element

Abstract

PURPOSE: To provide a crystal oscillation element with superior quality or reliability.SOLUTION: A crystal oscillation element comprises a crystal sheet, a first conductive layer, and a second conductive layer. The first conductive layer is positioned on the first surface of the crystal sheet. The second conductive layer is positioned on the second surface of the crystal sheet. The crystal sheet has a groove or opening that penetrates it. The angle between the side wall of the groove or opening and the first surface or second surface is between 60° and 90°.SELECTED DRAWING: Figure 1D

Description

[Technical Field]

[0001] The present invention relates to a quartz crystal oscillator, and more particularly to a quartz crystal oscillator having a groove or opening with sidewalls that have a specific range of angles. [Background technology]

[0002] A quartz crystal oscillator is an electronic component for generating vibration frequencies, and its manufacturing method is generally to appropriately cut a corresponding quartz crystal plate to form a suitable groove or opening pattern, and then package or cut it to form a corresponding quartz crystal oscillator or crystal oscillator element.

[0003] However, as electronic products become lighter, thinner, and smaller, the size of the crystal oscillators inside them must also shrink accordingly. However, in the process of forming the grooves or openings in the crystal oscillators, the quality and yield of the crystal oscillators are often significantly affected by the morphology of the grooves or openings. Therefore, how to improve the quality and reliability of crystal oscillators has become a research topic. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a quartz crystal oscillator element that can have excellent quality or reliability due to a corresponding manufacturing process and / or corresponding structural characteristics (for example, a specific range of angles of the sidewalls of the grooves or openings). [Means for solving the problem]

[0005] The present invention provides a crystal oscillator element with excellent quality and reliability.

[0006] The crystal oscillation element of the present invention includes a crystal sheet, a first conductive layer, and a second conductive layer. The first conductive layer is located on a first surface of the crystal sheet. The second conductive layer is located on a second surface of the crystal sheet. The crystal sheet has a groove or opening penetrating it. An angle of 60° to 90° is formed between the sidewall of the groove or opening and the first surface or the second surface. [Effects of the Invention]

[0007] As described above, the sidewalls of the grooves or openings in the quartz crystal sheet have angles of 60° to 90°, so that the quartz crystal oscillation element containing it has excellent quality and excellent reliability in applications. [Brief explanation of the drawings]

[0008] [Figure 1A] 1A and 1B are schematic top views of a part of a method for manufacturing a crystal oscillation element according to a first embodiment of the present invention. [Figure 1B] 2A to 2C are schematic cross-sectional views of a part of a method for manufacturing the crystal oscillation element according to the first embodiment of the present invention. [Figure 1C] 2A to 2C are schematic cross-sectional views of a part of a method for manufacturing the crystal oscillation element according to the first embodiment of the present invention. [Figure 1D] 2A to 2C are schematic cross-sectional views of a part of a method for manufacturing the crystal oscillation element according to the first embodiment of the present invention. [Figure 2] FIG. 4 is a schematic cross-sectional view of a crystal oscillation element according to a second embodiment of the present invention. [Figure 3A] 10A and 10B are partial cross-sectional schematic views of a part of a manufacturing method for a crystal oscillation element according to a third embodiment of the present invention. [Figure 3B] 10A and 10B are partial cross-sectional schematic views of a part of a manufacturing method for a crystal oscillation element according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a schematic cross-sectional view of a crystal oscillation element according to a fourth embodiment of the present invention. [Figure 5] 1 is a schematic top view of a crystal oscillation element according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the drawings, the size or appearance of some tissues or film layers may be enlarged, reduced, or exaggerated for clarity. For example, in the subsequent figures, the inclination angle and / or width of a groove or opening may be exaggerated. Furthermore, the numerical values ​​shown in the instructions may include deviations within the range of deviation acceptable to a person with ordinary knowledge in the relevant field. The deviations may be due to one or more standard deviations in the manufacturing or measurement process, or calculation errors caused by other factors such as the number of digits used in the calculation or conversion process, rounding, error propagation, etc.

[0010] In addition, directional terms, such as "up" or "down," used in the description merely refer to the directions of the accompanying drawings. Therefore, unless otherwise specified, the directional terms used are for explanatory purposes only and do not limit the present invention. In addition, to clearly show the directional relationships between different drawings, some drawings exemplarily show corresponding directions using a Cartesian coordinate system (i.e., an XYZ rectangular coordinate system), but the present invention is not limited thereto.

[0011] Fig. 1A is a schematic top view of a method for manufacturing a portion of a crystal oscillation element according to a first embodiment of the present invention, and Figs. 1B to 1D are schematic partial cross-sectional views of a method for manufacturing a portion of a crystal oscillation element according to the first embodiment of the present invention.

[0012] Referring to FIG. 1A, a quartz crystal plate 119 is provided. The quartz crystal plate 119 can be divided into multiple element regions 118. In subsequent processes, each element region 118 undergoes an appropriate process, resulting in each element region 118 becoming a corresponding quartz crystal oscillator element (e.g., the quartz crystal oscillator element 100 shown in FIG. 1D or another similar quartz crystal oscillator element). For simplicity, FIG. 1A does not show all of the element regions 118 one by one. Furthermore, subsequent cross-sectional views (e.g., FIGS. 1B to 1D) will be illustrated or described in terms of a single element region 118.

[0013] In one embodiment, the quartz plate 119 may be a quartz wafer, which may have a corresponding flat or notch, although the present invention is not limited thereto.

[0014] In one embodiment, the thickness of the quartz crystal plate 119 can be adjusted according to the requirements of the subsequent crystal oscillation element 100. For example, the thickness of the quartz crystal plate 119 may be approximately 20 micrometers (μm) to 50 μm. Furthermore, the present invention does not limit whether the thicknesses of the various portions of the quartz crystal plate 119 are consistent.

[0015] 1B, a corresponding patterned conductive layer can be formed on the quartz crystal plate 119 (shown in FIG. 1A) by an appropriate method (e.g., plating and lithography). For example, a corresponding first conductive layer 121 can be formed on the first surface 111 of the quartz crystal plate 119, and a corresponding second conductive layer 122 can be formed on the second surface 112 (the lower part of the figure) of the quartz crystal plate 119. In other words, the quartz crystal plate 119 can be sandwiched between the first conductive layer 121 and the second conductive layer 122. The layout design of the first conductive layer 121 or the second conductive layer 122 can be adjusted according to the requirements of the subsequent crystal oscillation device 100, and the present invention is not limited thereto.

[0016] 1B, a corresponding mask layer 151 can be formed or disposed on the first surface 111 of the quartz plate 119. The mask layer 151 can expose a portion of the first surface 111, making it suitable for a subsequent etching process.

[0017] In one embodiment, the mask layer 151 may be a patterned photoresist layer formed on the quartz plate 119. The patterned photoresist layer may cover the first conductive layer 121 and a portion of the first surface 111 exposed by the first conductive layer 121.

[0018] In one embodiment, the mask layer 151 may be a preformed metal mask, and the pattern of the metal mask may be formed by a suitable method (e.g., laser engraving), and the metal mask may be disposed on the first conductive layer 121 and / or on the portion of the first surface 111 exposed by the first conductive layer 121 by a suitable method (e.g., adhesive).

[0019] 1C-1D, a corresponding dry etching process is used to remove a portion of the quartz plate 119 to form a corresponding groove or opening 130 (shown in FIG. 1D). The groove or opening 130 is formed by removing a portion of the quartz plate 119 from the first surface 111 toward the second surface 112. In this manner, as shown in FIG. 1D, the minimum width of the groove or opening 130 on the first surface 111 (also referred to as the first width W1) can be greater than or equal to the minimum width of the groove or opening 130 on the second surface 112 (also referred to as the second width W2).

[0020] Compared with wet etching processes, dry etching processes are less prone to side etching and undercutting (although they cannot be completely eliminated). Furthermore, compared with wet etching processes, dry etching processes allow for easier adjustment or control of the dry etching direction or angle through the use of a corresponding etching agent. In this way, the corresponding dry etching processes can easily control the corresponding angles, allowing the axial angles of different etching portions (i.e., the directions or angles of the imaginary central axes of corresponding relative side surfaces on the cross section) to match. They can also have a better aspect ratio. In this way, the manufactured crystal oscillator 100 can have better quality and / or yield. It should be noted that some dry etching processes (e.g., laser ablation and mechanical drilling) do not necessarily require the mask layer 151.

[0021] In one embodiment, the dry etching process may include a reactive ion etching (RIE) process, such as an inductively coupled plasma reactive ion etching (ICP-RIE) process. The etchant used in the reactive ion etching process may include a fluorine-based etchant. Examples of the fluorine-based etchant include, but are not limited to, trifluoromethane (CHF), carbon tetrafluoride (CF), octafluorocyclobutane (CF), sulfur hexafluoride (SF), mixtures thereof, or mixtures of these with other reactive gases or noble gases (e.g., CF / O, SF / Ar, or CF / He). Compared with mechanical drilling and powder blasting processes, reactive ion etching processes are less susceptible to stress and material damage during the etching process, and compared with laser drilling processes, reactive ion etching processes are less susceptible to heat concentration (e.g., the material absorbs laser light, generating heat in a localized area) or material damage during the etching process.

[0022] Referring to FIG. 1D, after forming the corresponding trenches or openings 130, the corresponding mask layer 151 (if present) may be removed by any suitable method.

[0023] Referring to FIG. 1D, after forming the corresponding grooves or openings 130, the respective element regions of the quartz plate 119 can be appropriately cut in an appropriate manner to form the corresponding quartz oscillator elements 100.

[0024] After the above-described processes, the manufacturing of the crystal oscillation element 100 of this embodiment is almost completed. However, it should be noted that the manufacturing method of the crystal oscillation element 100 of FIG. 1D is not completely limited to the above-described method.

[0025] Referring to FIG. 1D, the crystal oscillation element 100 includes a crystal sheet 110, a first conductive layer 121, and a second conductive layer 122. The first conductive layer 121 is located on the first surface 111 of the crystal sheet 110. The second conductive layer 122 is located on the second surface 112 of the crystal sheet 110. The crystal sheet 110 has a groove or opening 130 extending therethrough. In cross section (as shown in FIG. 1D), the angle θ between the sidewall 130d of the groove or opening 130 and the first surface 111 or the second surface 112 is between 60° and 90° (although it may be close to, but not 90°). It should be noted that in angle measurements, the first surface 111 or the second surface 112 may refer to an imaginary plane extending from it (either the first surface 111 or the second surface 112) or an imaginary plane parallel to it. The corresponding angle θ can also be obtained by direct measurement (e.g., measuring with an optical microscope or electron microscope after cutting) or indirect estimation (e.g., estimating using trigonometric functions after confirming the position of the groove or opening 130 on the first surface 111 and the second surface 112).

[0026] In one embodiment, the angle θ may be close to, but not equal to, approximately 60°, 65°, 70°, 75°, 80°, 85°, 90°, or may be in a range between any two of the values ​​listed above, or a corresponding value within the range between any two of the values ​​listed above.

[0027] In one embodiment, for grooves or openings 130 formed by reactive ion etching, the angle θ may be between 80° and 90° (although it may be close to, but not 90°).

[0028] In one embodiment, the smallest width of the groove or opening 130 on the first surface 111 (also referred to as the first width W1) may be greater than or equal to the smallest width of the groove or opening 130 on the second surface 112 (also referred to as the second width W2). In one embodiment, the second width W2 may be approximately 80% to 100% of the first width W1. In one embodiment, describing a groove or opening 130 formed by reactive ion etching, the second width W2 may be approximately 99% to 100% of the first width W1.

[0029] In one embodiment, the angle between the central axis A of the groove or opening 130 and the first surface 111 or the second surface 112 is between 75° and 90°. In one embodiment, for grooves or openings 130 formed by reactive ion etching, the angle between the central axis A and the first surface 111 or the second surface 112 may be between 83° and 90°.

[0030] In one embodiment, in cross section (as shown in FIG. 1D), the sidewalls 130d of the grooves or openings 130 present essentially corresponding flat surfaces.

[0031] In one embodiment, in cross section (as shown in FIG. 1D ), the depth of the groove or opening 130 (which may correspond to the thickness T of the quartz crystal sheet 110 forming the groove or opening 130) may be at least about 1.5 times the minimum width of the groove or opening 130, or more. In one embodiment, in cross section (as shown in FIG. 1D ), the depth of the groove or opening 130 (which may correspond to the thickness T of the quartz crystal sheet 110 forming the groove or opening 130) may be about 6 times the minimum width of the groove or opening 130, or more. In one embodiment, in cross section (as shown in FIG. 1D ), the depth of the groove or opening 130 is 6 to 10 times the minimum width of the groove or opening 130. In one embodiment, the depth of the groove or opening 130 (which may correspond to the thickness T of the quartz crystal sheet 110 forming the groove or opening 130) may be about 80 μm. In one embodiment, the minimum width of the groove or opening 130 may be about 10 μm to 20 μm.

[0032] 2 is a schematic cross-sectional view of a crystal oscillation element according to a second embodiment of the present invention. The crystal oscillation element 20 of this embodiment may be the same as or similar to the crystal oscillation element 10 described above in terms of structure or manufacturing method, so similar structures or parts are denoted by the same reference numerals and descriptions thereof are omitted.

[0033] Referring to FIG. 2, the crystal oscillation element 200 includes a crystal sheet 110, a first conductive layer 121, and a second conductive layer 122. The first conductive layer 121 is located on a first surface 111 of the crystal sheet 110. The second conductive layer 122 is located on a second surface 112 of the crystal sheet 110. The crystal sheet 110 has a groove or opening 230 extending therethrough. In cross section (shown in FIG. 2), an angle θ between the sidewall 230d of the groove or opening 230 and the first surface 111 or the second surface 112 is between 60° and 90°. The manufacturing method of the crystal oscillator 200 is similar to the manufacturing method of the crystal oscillator 100, except that in the process of forming the grooves or openings 230, a metal mask can be placed on the second conductive layer 122 and / or on a portion of the second surface 112 exposed by the second conductive layer 122, and then the corresponding grooves or openings 230 are formed by removing a portion of the crystal plate 119 from the first surface 111 toward the second surface 112.

[0034] 3A and 3B are partial cross-sectional schematic views of a manufacturing method for a portion of a crystal oscillation element according to a third embodiment of the present invention. Crystal oscillation element 300 of this embodiment may be the same as or similar to crystal oscillation element 100 described above in terms of structure or manufacturing method, and similar structures or components are denoted by the same reference numerals and descriptions thereof will be omitted. For example, the manufacturing method for crystal oscillation element 300 of this embodiment can be carried out by continuing the steps shown in FIG. 1C.

[0035] 1C and 3A, after removing a portion of the quartz crystal plate 119 from the first surface 111 toward the second surface 112, the structure shown in FIG. 1C can be inverted. Then, as shown in FIG. 3A, a portion of the quartz crystal plate 119 is removed from the second surface 112 toward the first surface 111.

[0036] For example, a corresponding mask layer 352 can be formed or disposed on the second surface 112 of the quartz plate 119. The mask layer 352 can expose a portion of the second surface 112, making it suitable for a subsequent etching process.

[0037] It should be noted that the mask layer 351 can be formed at an appropriate step. For example, in the embodiment shown in Figures 1C and 3A, the mask layer 352 can be formed after the step shown in Figure 1C. In an embodiment not shown, the corresponding mask layer 352 can be formed or disposed on the second surface 112 of the quartz plate 119 before removing a portion of the quartz plate 119 (e.g., the step shown in Figure 1C).

[0038] Referring to Figures 3A-3B, corresponding grooves or openings 130 can be formed in a manner similar to that shown in Figures 1C-1D.

[0039] It should be noted that mask layer 351 can be removed in an appropriate step. For example, in the embodiment shown in FIGS. 1C and 3A-3B, mask layer 151 (shown in FIG. 1C) can be removed first, and then mask layer 352 (shown in FIG. 3A) can be removed. In an embodiment not shown, mask layer 151 (shown in FIG. 1C) and mask layer 352 (shown in FIG. 3A) can be removed together in the same step.

[0040] With continued reference to FIG. 3B, after forming the corresponding grooves or openings 330, the corresponding crystal oscillation elements 300 can be constructed by appropriately cutting each element area of ​​the crystal plate 119 in an appropriate manner.

[0041] After the above-described processes are performed, the manufacturing of the crystal oscillation element 300 of this embodiment is almost completed. However, it should be noted that the manufacturing method of the crystal oscillation element 300 of FIG. 3B is not completely limited to the above-described method.

[0042] Referring to FIG. 3B, the crystal oscillation element 300 includes a crystal sheet 110, a first conductive layer 121, and a second conductive layer 122. The first conductive layer 121 is located on a first surface 111 of the crystal sheet 110. The second conductive layer 122 is located on a second surface 112 of the crystal sheet 110. The crystal sheet 110 has a groove or opening 330 extending therethrough. In cross section (shown in FIG. 3D), an angle θ between the sidewall 330d of the groove or opening 330 and the first surface 111 or the second surface 112 is between 60° and 90°.

[0043] The manufacturing methods for crystal oscillation element 300 and crystal oscillation element 100 are similar, but differ in the formation of grooves or openings 330. Furthermore, structurally, the minimum width of grooves or openings 330 on first surface 111 (also referred to as first width W1) can be made closer to the minimum width of grooves or openings 330 on second surface 112 (also referred to as second width W2). For example, the ratio of first width W1 to second width W2 may be approximately 0.99 to 1.01.

[0044] In this embodiment, the horizontal position of the narrowest portion of groove or opening 330 is located between first surface 111 and second surface 112. In one embodiment, the width W3 of the narrowest portion is approximately 99.5% to 100% of the first width W1 or the second width W2.

[0045] In one embodiment, in cross section (as shown in FIG. 3C), the sidewall 330d of the groove or opening 330 has a first portion 331 near the first surface 111 and a second portion 332 near the second surface 112. The first portion 331 and / or the second portion 332 essentially exhibit corresponding flat surfaces. Briefly, in cross section (as shown in FIG. 3B), the groove or opening 330 may be hourglass-shaped.

[0046] 4 is a schematic cross-sectional view of a crystal oscillation element according to a fourth embodiment of the present invention. The crystal oscillation element 400 of this embodiment may be the same as or similar to the crystal oscillation element 100 described above in terms of structure or manufacturing method, so similar structures or parts are denoted by the same reference numerals and descriptions thereof are omitted.

[0047] Referring to FIG. 4, the crystal oscillation element 400 includes a crystal sheet 110, a first conductive layer 121, and a second conductive layer 122. The first conductive layer 121 is located on a first surface 111 of the crystal sheet 110. The second conductive layer 122 is located on a second surface 112 of the crystal sheet 110. The crystal sheet 110 has a groove or opening 130 extending therethrough. In cross section (shown in FIG. 4), the angle θ between the sidewall 430d of the groove or opening 430 and the first surface 111 or the second surface 112 is between 60° and 90°.

[0048] The manufacturing method or corresponding structure of crystal oscillation element 400 may be similar to the manufacturing method or corresponding structure of crystal oscillation element 100, except that the angle θ between central axis A and first surface 111 or second surface 112 may be less than 90°. This may occur (but the present invention is not limited to this) when the etching target is placed in an inclined direction during the formation of groove or opening 430, but this does not have any significant effect on the structure and / or corresponding use of crystal oscillation element 400.

[0049] FIG. 5 is a schematic top view of a portion of a crystal oscillation element according to one embodiment of the present invention.

[0050] The crystal oscillation element 500 includes a crystal sheet 110, a first conductive layer 121, and a second conductive layer 122. The first conductive layer 121 is located on the first surface 111 of the crystal sheet 110. The second conductive layer 122 is located on the second surface 112 of the crystal sheet 110. The crystal sheet 110 has a groove or opening 530 extending therethrough. Furthermore, a cross section of the crystal oscillation element 500 taken along the A-A' cross section may be as shown in FIG. 1D, 2, 3B, or 4, for example. A cross section of the crystal oscillation element 500 taken along the B-B' cross section may be as shown in FIG. 1D, 2, 3B, or 4, for example. That is, the contours of the sidewalls 530d of the groove or opening 530 can be essentially the same in different directions (the direction along the A-A' cross section and the direction along the B-B' cross section). That is, the surface of the sidewall 530 d of the groove or opening 530 has essentially no direct relationship with the lattice plane of the quartz crystal sheet 110 .

[0051] As described above, in the crystal oscillation element of the present invention, the sidewalls of the grooves or openings in the crystal sheet have angles of 60° to 90°, so the crystal oscillation element has excellent quality and excellent reliability in applications. [Industrial Applicability]

[0052] The crystal oscillator of the present invention can generate vibration frequencies and can be applied to electronic products such as, but not limited to, communication, information, and consumer electronics. [Explanation of symbols]

[0053] 100, 200, 300, 400, 500 crystal oscillator 119 Crystal plate 118 Element Area 110 Crystal Sheet 111 1st surface 112 Second surface 121 First conductive layer 122 Second conductive layer 151, 352 mask layer 130, 230, 330, 430, 530d Groove or opening 130d, 230d, 330d, 430d, 530d side wall 331 Part 1 332 Part 2 W1 1st width W2 Second width W3 Width at narrowest point θ angle A Intermediate shaft T Thickness

Claims

1. Crystal sheet and a first conductive layer located on a first surface of the quartz crystal sheet; a second conductive layer located on a second surface of the quartz crystal sheet; wherein the quartz crystal sheet has a groove or opening passing therethrough, and an angle between a sidewall of the groove or opening and the first surface or the second surface is 60° to 90°.

2. 2. The crystal oscillation element according to claim 1, wherein the groove or opening is formed by dry etching.

3. 2. The crystal oscillation element according to claim 1, wherein an angle between the central axis of the groove or opening and the first surface or the second surface is 75° to 90°.

4. 2. The crystal oscillation element according to claim 1, wherein the contours of the sidewalls of the grooves or openings are consistent in different cross sections.

5. 2. The crystal oscillation element according to claim 1, wherein the depth of the groove or opening is 1.5 times or more the minimum width of the groove or opening.

6. 2. The crystal oscillation element according to claim 1, wherein the width of the groove or opening in cross section gradually increases from the second surface toward the first surface.

7. 2. The crystal oscillation element according to claim 1, wherein the sidewall of the groove or opening has a flat surface in cross section.

8. 2. The crystal oscillation element according to claim 1, wherein the horizontal position of the narrowest portion of the groove or opening is located between the first surface and the second surface.

9. 2. The crystal oscillation element of claim 1, wherein the sidewall of the groove or opening has a first portion near the first surface and a second portion near the second surface, the first portion and the second portion presenting corresponding flat surfaces.

10. 10. The crystal oscillation element according to claim 8, wherein the groove or opening is formed by a dry etching method performed multiple times.

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