JP2010004484A - Crystal oscillator, electronic component, and method of manufacturing element for crystal oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an element for a crystal oscillator in which characteristic degradation, caused by the effect of side etching, that may occur when forming an outer shape of a crystal reed through etching, can be suppressed, crystal oscillator and electronic component with the element for the crystal oscillator. <P>SOLUTION: The element for the crystal oscillator is manufactured by implementing the steps of, when manufacturing the element for the crystal oscillator: forming an outer shape mask pattern 68 for forming an outer shape of a crystal reed 1 on an AT-cut crystal wafer W such that a connection supporting part 34 connecting the crystal reed 1 and the wafer W after etching can comes to a +X axis side; forming the outer shape of the crystal reed 1 rectangular; and forming extraction electrodes 32, 33 in an area at a side of the connection supporting part 34 in the crystal reed 1 and forming excitation electrodes 30, 31 in an area of a -X side rather than the extraction electrodes 32, 33 in the crystal reed 1 to obtain the element for the crystal oscillator. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for manufacturing a crystal resonator element using an AT-cut crystal piece.

  Conventionally, as a method of obtaining a large number of rectangular crystal pieces from an AT-cut crystal wafer, a method of cutting by dicing so that long sides are formed along the X axis is known. Is formed, and a lead electrode is formed on the −X side (minus side on the X axis). On the other hand, the present inventor is considering forming the outer shape of the crystal piece by wet etching. FIG. 11 is a diagram showing this state. As shown in FIGS. 11A and 11B, the wafer W1 after forming the outer shape is connected to the central portion of one side which is the short side of the rectangular crystal piece 101. FIG. A support portion 134 is formed, and the crystal piece 101 is connected to and supported by the wafer W1, and the crystal pieces 101 are arranged vertically and horizontally.

  In the crystal piece 101 obtained in this way, the excitation electrode 130 and the extraction electrodes 132 and 133 are formed in a state of being supported by the wafer W1, and in a region including the edge portion on the opposite side to the connection support portion 134. Lead electrodes 132 and 133 are formed on the excitation electrode 130 and the connection support part 134 side, respectively. This is because the shape of the edge portion deteriorates when the connection support portion 134 is cut during handling, and if the connection support portion 134 side is set as a vibration region, the shape deterioration adversely affects the characteristics of the crystal resonator. Also in Patent Document 1, the excitation electrode 130 is formed on the + X side in the drawing, and the extraction electrodes 132 and 133 are formed on the −X side. The reason for this is that a crystal resonator element in which the excitation electrode 130 is formed on the + X side is used. This is because it is known as common sense that the characteristics of the crystal resonator become the best when used.

However, when the idea of dicing is applied as it is to the outer shape formation by wet etching, it has been found that the following problems occur. That is, when a mask is formed in the region corresponding to the crystal piece 101 and the periphery thereof is etched, the crystal is anisotropically etched, and the etching rate toward the negative side of the X axis is higher than the etching rate toward the positive side of the X axis. Therefore, etching progresses quickly at the corner on the + X side, so-called side etching occurs, and the eroded portion S is formed. Since the external shape of the crystal piece affects the temperature characteristics, if the eroded portion S is formed at the corner of the crystal piece on the excitation electrode side, the temperature characteristics of the planned frequency cannot be obtained. The smaller the crystal piece, the greater the proportion of the eroded portion S occupied on the crystal piece, and the greater the influence of the eroded portion S. Furthermore, if the crystal piece 101 has a distorted shape, scratches or the like are likely to occur before the crystal resonator element is handled and mounted on the base, and therefore there is a high risk of being a defective product.
JP 2007-318350 A (paragraph number 0031)

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a crystal resonator element capable of suppressing deterioration of characteristics due to the influence of side etching that occurs when forming the outer shape of a crystal piece by wet etching, and its element It is an object of the present invention to provide a manufacturing method, a crystal resonator and an electronic component provided with the crystal resonator element.

In the method for manufacturing a crystal resonator element of the present invention,
Forming a mask for forming a rectangular shape of the crystal piece on the AT-cut crystal wafer so that a connection support portion for connecting the crystal piece after etching and the wafer is on the + X-axis side;
Next, the wafer is brought into contact with an etching solution to form a crystal piece in a rectangular shape;
Thereafter, forming a lead electrode in a region on the connection support portion side of the crystal piece and forming an excitation electrode in a region on the −X side of the lead electrode in the crystal piece to obtain a crystal resonator element. It is characterized by that.

  The crystal resonator of the present invention includes a container in which the element for crystal resonator manufactured by the above manufacturing method is sealed, and a terminal portion provided in the container and electrically connected to the lead electrode. It is characterized by that. An electronic component of the present invention includes the above-described crystal resonator and an oscillation circuit for causing the crystal resonator to oscillate.

  According to the present invention, since the extraction electrode is located on the + X side of the rectangular crystal piece obtained from the AT-cut crystal wafer, it may not be advantageous when the crystal piece is cut out by dicing. However, even if erosion (side etching) occurs at the corners on the + X side, it is possible to suppress the deterioration of the temperature characteristics of the frequency. As a result, good characteristics can be obtained. Therefore, it can be said that the production method of the present invention is an excellent method.

  A method for manufacturing a crystal resonator element according to an embodiment of the present invention will be described with reference to FIGS. First, as shown in FIG. 1, etching is performed on each section 5 of the wafer W from which the crystal piece 1 (see FIG. 3E to be described later) is cut, and the thickness of the wafer W in each section 5 is formed. The thickness is adjusted so that the natural frequency of the crystal piece 1 becomes a desired frequency. Specifically, as shown in FIGS. 1A and 1B, a metal film 60 made of Cr (chrome) and Au (gold) and a resist film 61 are formed on the front and back surfaces of the wafer W, respectively. Then, a resist mask is formed by photolithography, and the metal film 60 is etched by a KI (potassium iodide) solution to form a laminated mask 90 corresponding to each section 5.

  Then, as shown in FIG. 1C, the wafer W is immersed in a hydrofluoric acid solution, the wafer W is etched, the frequency is confirmed by a probe (not shown), the metal film 60 on the back surface of the wafer W, and the resist film 61. Then, the resist film 61 on the surface of the wafer W is peeled off. As a result, as shown in FIG. 2, a plurality of sections 5 whose thicknesses are adjusted to the planar shape of the wafer W are formed. Note that FIG. 2 shows a state in which the thickness adjustment has been performed for only one of the sections 5, and the description of the other sections 5 is omitted only by indicating the positions of the sections 5. Further, the cross-sectional view of the wafer W shown in FIG. 1 shows a cross section taken along line AA shown in FIG.

  Next, as shown in FIG. 3A, after the thickness of the wafer W is adjusted, a metal film 62 and a resist film 63 are formed on the front and back surfaces of the wafer W, and the metal film 62 and the resist film 63 are described above. As shown in FIG. 3B, an outer shape mask pattern 68 for forming the outer shape of the crystal piece 1 is formed on both the front and back surfaces of the wafer W by etching using photolithography and KI solution. As shown in FIG. 4, the external mask pattern 68 has a connection support portion 34 that can be supported in a state in which the crystal piece 1 is held in the compartment 5 when the crystal piece 1 is formed in the central portion of the side surface in the + X direction of the compartment 5. It is formed so that can be formed. 3 and FIG. 5 and FIG. 7 to be described later are cross-sectional views taken along the line B-B shown in FIG.

  After forming the outer shape mask pattern 68, as shown in FIG. 3C, the wafer W is etched along the outer shape mask pattern 68 to form a groove portion 71 on the upper surface side of the wafer W and a groove portion 72 on the lower surface side of the wafer W. To go. As the etching progresses, the bottom surfaces of both the groove portions 71 and 72 become thin and the bottom surface disappears and penetrates up and down to form a through groove 73 as shown in FIG. The crystal piece 1 is cut off from. Then, the resist film 63 and the metal film 62 remaining on the front surface and the back surface of the wafer W are peeled off, and the crystal piece 1 is subjected to a cleaning process, thereby obtaining the crystal piece 1 as shown in FIGS. The center portion of the short side on the + X side is connected and supported by the connection support portion 34 to the wafer W, and thus the outer shape forming step of the crystal piece 1 is performed.

  When the crystal piece 1 is formed by etching as in this embodiment, the description is omitted in FIG. 3 (e), but the crystal piece 1 is connected as shown in FIGS. 5 (a) and 5 (b). An erosion portion S is formed at the corner of the crystal piece 1 on the + X side where the support portion 34 is formed. The reason why the eroded portion S is formed will be described with reference to FIG. 6 is an enlarged view of the vicinity of the + X side outer shape mask pattern 68 shown in FIG. 3. FIG. 6 (a) is shown in FIG. 3 (b), FIG. 6 (b) is shown in FIG. FIG. 6C corresponds to FIG. 3D, respectively.

  As shown in FIG. 6A, after the outer shape mask pattern 68 is formed, the outer shape formation of the crystal piece 1 is started by etching. At this time, the etching is performed as + X as described above due to the anisotropy of the crystal. Since the etching rate toward the −X side is faster than the etching rate toward the side, the etching proceeds obliquely from the + X side to the −X side above and below the wafer W as schematically shown by arrows in the figure. For this reason, as shown in FIG. 6B, the back side portion of the outer shape mask pattern 68 is deeply eroded (side etching occurs) at the corner of the crystal piece 1 on the + X side. Further, when the outer shape of the crystal piece 1 is formed, etching is also performed on the left and right sides in the Z direction. Therefore, at the corner on the + X side of the crystal piece 1, the hydrofluoric acid solution is also eroded from the Z direction in the eroded region. . Therefore, in the boundary region between the + X side metal film 62 and the crystal piece 1, erosion proceeds most at the four corners on the + X side.

  Therefore, when the through groove 73 is formed as shown in FIG. 6C, the eroded portion S is formed in the side-etched portion. Further, the right side portion of FIG. 6 is the remaining portion of the wafer W, and side etching still occurs on the −X side of the remaining portion, but the degree is small. Since this portion is the same as the state of etching at the −X side corner of the crystal piece 1, side etching that affects the characteristics of the crystal resonator does not occur at the −X side corner of the crystal piece 1. Absent.

  In this embodiment, when the excitation electrode and the extraction electrode are formed on the crystal piece 1 whose shape has deteriorated due to the erosion portion S, each electrode is formed so that the deterioration of the characteristics of the crystal resonator due to the erosion portion S can be suppressed. is doing. Next, the formation process of the excitation electrode and the extraction electrode of this embodiment will be described with reference to FIG. First, as shown in FIG. 7A, after the outer shape of the crystal piece 1 is formed, a metal film 64 and a resist film 65 are formed on the entire surface of the crystal piece 1 and etched by photolithography and a KI solution. As shown, mask patterns corresponding to the shapes of the excitation electrodes 30 and 31 and the extraction electrodes 32 and 33 of the crystal resonator element are formed on the entire surface of the crystal piece 1.

  Then, as shown in FIG. 7C, the metal film 64 is etched to form the excitation electrodes 30 and 31 on the −X side and the extraction electrodes 32 and 33 on the + X side, as shown in FIG. The resist film 65 is removed to form a crystal resonator element. As a result, as shown in FIG. 8, a wafer W on which the crystal resonator element connected and supported by the connection support portion 34 is formed in each of the sections 5 on the wafer W. Then, as shown in FIG. 7E, the connection support portion 34 is cut by, for example, laser dicing to manufacture a piece of crystal resonator element. FIG. 8 shows the state in which the crystal resonator element is formed in only one of the sections 5 as in FIG. 2, and the description of the other sections 5 is omitted only by indicating the positions of the sections 5. Yes.

  Next, a crystal resonator element manufactured by the manufacturing method of the present embodiment will be described with reference to FIG. As shown in FIGS. 9A and 9B, the crystal resonator element is excited on the upper surface 11 and the lower surface 12 of the crystal piece 1 at positions closer to the front side surface 13 than the center. Electrodes 30 and 31 are formed, and lead electrodes 32 and 33 are formed on the rear side surface 14 side. The extraction electrode 32 has an upper surface electrode 41 formed on the upper surface 11 and a lower surface electrode 42 formed on the lower surface, and a side electrode 43 formed on the rear side surface 14 connecting the upper surface electrode 41 and the lower surface electrode 42; An extension 44 formed by extending the upper surface electrode 41 connected to the excitation electrode 30 is provided. Similarly to the extraction electrode 32, the extraction electrode 33 includes a lower surface electrode 45, an upper surface electrode 46, a side electrode 47, and an extension portion 48. The extension portion 48 extends from the lower surface electrode 45 and is connected to the excitation electrode 31. Except for this point, it has substantially the same configuration as the extraction electrode 32. And in this embodiment, the erosion part S by side etching is formed only in the rear side surface 14 side of the crystal piece 1 in which the extraction electrodes 32 and 33 are formed.

  According to the present embodiment described above, when the crystal piece 1 is externally formed so that the connection support portion 34 is located on the + X side from the crystal wafer W that has been AT-cut by etching, the lead electrodes 32 and 33 are formed. The corner portion included in the vibration region formed on the + X side of the crystal piece 1 and vibrated by the excitation electrodes 30 and 31 is positioned on the −X side. For this reason, even if the shape deterioration due to the eroded portion S occurs, it is possible to suppress an adverse influence on the temperature characteristics of the frequency of the crystal resonator. Therefore, by using the manufacturing method of the present embodiment, even if the crystal piece 1 is formed in such a manner that the eroded portion S is formed by side etching at the corner on the + X side by wet etching, the problem of conventional characteristic deterioration occurs. As compared with a crystal resonator in which an excitation electrode is formed on the + X side, a crystal resonator having excellent characteristics can be provided.

  Next, a crystal resonator 10 using the crystal resonator element of the present embodiment will be described with reference to FIG. As shown in FIGS. 10A and 10B, the crystal resonator 10 conducts the lead electrodes 32 and 33 of the crystal resonator element to a pair of electrodes 81 provided in the exterior body (container) 8. It mounts by adhering in the aspect electrically connected by the adhesive agent 82. FIG. And the external electrode 83 and the electrode 81 provided in the lower part of the exterior body 8 are electrically connected via the wiring in the exterior body 8, and this external electrode 83 is connected with the electrode of an electronic device (electronic component). By connecting, the crystal resonator element and the electronic device are electrically connected.

  In this crystal resonator 10, the lead electrodes 32 and 33 where the erosion part S is formed are fixed ends, and the excitation electrodes 30 and 31 are free ends. Therefore, the portion where the erosion part S is formed does not vibrate and vibrates. On the excitation electrodes 30 and 31 side, there is no erosion part, the distance from the fixed end to each corner of the free end is constant, and the weight balance is stabilized. As a result, the vibration of the crystal resonator element is stabilized, so that it is easy to provide a crystal resonator having a temperature characteristic of a desired frequency even if the shape of the crystal piece 1 is deteriorated by the erosion portion S.

It is a 1st explanatory view for explaining the manufacturing process of the element for crystal oscillators. 1 is a plan view showing an outline of a quartz wafer W for manufacturing a crystal resonator element. FIG. It is the 2nd explanatory view for explaining the manufacturing process of the element for crystal oscillators. 5 is a plan view for explaining an outer shape mask pattern 68. FIG. 2 is a plan view for explaining the shape of a crystal piece 1. FIG. FIG. 5 is an enlarged cross-sectional view of the vicinity of a + X side external mask pattern 68; It is the 3rd explanatory view for explaining the manufacturing process of the element for crystal oscillators. 2 is a plan view showing a state in which a crystal resonator element is formed on a wafer W. FIG. It is a perspective view which shows the outline of the element for crystal oscillators of this embodiment. It is the schematic for demonstrating the shape of the crystal oscillator 10 incorporating the element for crystal oscillators. It is a top view for demonstrating the conventional element for crystal oscillators.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crystal piece 8 Exterior body 10 Crystal oscillator 11 Upper surface 12 Lower surface 14 Rear side surface 30, 31 Excitation electrode 32, 33 Extraction electrode 34 Connection support part 41, 46 Upper surface electrode 42, 45 Lower surface electrode 43, 47 Side electrode 44, 48 Extension Electrode S erosion part

Claims (3)

Forming a mask for forming a rectangular shape of the crystal piece on the AT-cut crystal wafer so that a connection support portion for connecting the crystal piece after etching and the wafer is on the + X-axis side;
Next, the wafer is brought into contact with an etching solution to form a crystal piece in a rectangular shape;
Thereafter, forming a lead electrode in a region on the connection support portion side of the crystal piece and forming an excitation electrode in a region on the −X side of the lead electrode in the crystal piece to obtain a crystal resonator element. A method for manufacturing an element for a crystal resonator. A container in which the quartz resonator element manufactured by the manufacturing method according to claim 1 is sealed;
And a terminal portion provided in the container and electrically connected to the extraction electrode.   An electronic component comprising the crystal resonator according to claim 2 and an oscillation circuit for causing the crystal resonator to oscillate.

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