JP2013085298A - Element for crystal oscillator, crystal oscillator, and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an element for a crystal oscillator which inhibits flow of a conductive adhesive from an extraction electrode when the extraction electrode is fastened to an electrode of a crystal piece support member through the conductive adhesive.SOLUTION: A crystal oscillator element includes: a crystal piece where a step is formed in a circumferential direction so that the thickness of a center part becomes larger than the thickness of a peripheral part; excitation electrodes exciting the center part; the extraction electrodes which are formed so as to be extracted from the respective excitation electrodes to a peripheral part on one surface side of the crystal piece and are fastened to electrodes of the crystal piece support member through the conductive adhesive; and short prevention protruding parts which are provided between the excitation electrode provided on the one surface side of the crystal piece at the peripheral part and the extraction electrode extracted from the excitation electrode on the other surface side of the crystal piece to the one surface side and are integrally formed with the crystal piece for preventing the conductive adhesive applied to the extraction electrodes from flowing to the excitation electrodes.

Description

  The present invention relates to a crystal resonator element, a crystal resonator including the crystal resonator element, and an electronic component including the crystal resonator.

  The element for a crystal oscillator has, for example, a crystal piece (crystal blank) and a pair of excitation electrodes (excitation electrodes) provided on the front and back surfaces of the crystal piece, respectively, and a voltage is applied to the excitation electrode. It is an element that utilizes the characteristic that crystal vibration is excited by the piezoelectric inverse effect of quartz when applied. For example, a crystal resonator element is housed in a package for protecting it and manufactured as a crystal resonator, and the crystal resonator is widely used in electronic components such as an oscillator as a reference source for frequency and time.

  In some cases, the peripheral area on the front and back surfaces of the crystal piece is lower than the central area and has a step. In this case, the central area is used as an excitation part, and the excitation is applied to the excitation part. An electrode may be formed. The purpose of configuring the crystal piece in this way is to confine the vibration energy in the excitation unit and obtain a good crystal impedance (CI) value.

  FIG. 21A and FIG. 21B show a surface and a longitudinal section of the crystal resonator element 1 in which steps are formed as described above. In the figure, 11 is a crystal piece, 12 is an excitation part, 13 is a peripheral part (bevel part), and 14 is an excitation electrode. Reference numeral 15 denotes an extraction electrode, which is formed so as to be extracted from the excitation unit 12 to the peripheral portion 13 and further to the back surface through the side surface of the crystal piece 11. In the figure, 16 is an excitation electrode formed on the back surface of the crystal piece 11, and 17 is a lead electrode formed so as to be drawn from the back surface to the surface. The back surface of the crystal resonator element 1 is the same as the surface. The excitation electrode 16 and the extraction electrode 17 are provided so as to have the following layout.

  In this way, the step of forming a step in the crystal piece 11 and the step of forming the outer shape of the crystal piece 11 are performed by performing photolithography on the crystal wafer, forming an etching mask, and performing wet etching along the etching mask. It is carried out by doing. When the crystal resonator element 1 is manufactured as the crystal resonator, electrodes formed on the base (substrate) of the package corresponding to the extraction electrodes 15 and 17, respectively, and the extraction electrodes 15, 17 are bonded to each other through the conductive adhesive 18.

  By the way, along with the miniaturization of the above-described electronic components on which the crystal resonator is mounted, the crystal resonator has been miniaturized, and the crystal resonator element has also been miniaturized accordingly. However, as the crystal resonator element 1 is further reduced in size, the distance between the extraction electrodes 15 and 17 and the excitation electrodes 14 and 16 and the distance between the extraction electrodes 15 and 17 are reduced. As a result, when the base electrode and the extraction electrode are bonded, the conductive adhesive 18 flows from the extraction electrodes 15 and 17 to the outside as shown in FIG. 22, and the excitation electrode 14 (16) and The conductive adhesive 18 is applied to the extraction electrode 17 (15), or the conductive adhesive 18 is applied to the extraction electrode 15 and the extraction electrode 17, so that the electrodes are short-circuited, and the produced crystal vibration The child may become defective.

  Although it is conceivable to reduce the coating amount of the conductive adhesive 18, there is a limit, and for example, it is conceivable to use a conductive adhesive having low fluidity. In order to ensure, there is a limit to the types of adhesives that can be used, so selection of such adhesives may not address them.

Patent Document 1 describes a tuning-fork type crystal resonator element in which a convex portion is provided around an extraction electrode. However, a flat crystal piece having a thickness different between a central portion and a peripheral portion is disclosed. Application to is not described. In addition, Patent Document 2 describes that a groove is formed in a portion where a lead electrode of a crystal piece is formed. This is also a flat crystal piece and has a thickness between a central portion and a peripheral portion. It is not described to apply to different things.
JP2003-152499 (paragraph 0038, paragraph 0039 and FIG. 10) JP 2007-96901 (FIGS. 2 and 3)

  An object of the present invention is to provide a crystal piece in which a step is formed so that the thickness of the peripheral portion is smaller than that of the center portion, an excitation electrode for exciting the crystal piece, In a crystal resonator element having a connected lead electrode, when the lead electrode is fixed to the electrode of the crystal piece support member via a conductive adhesive, the flow of the adhesive from the lead electrode is suppressed. The present invention provides a crystal resonator element capable of ensuring normal conductivity between an electrode of the crystal piece support member and a lead electrode, and a crystal resonator and an electronic device including the crystal resonator element. To provide parts.

The quartz resonator element of the present invention has a crystal piece in which a step is formed in the circumferential direction on one surface and the other surface so that the thickness of the central portion is larger than the thickness of the peripheral portion,
An excitation electrode for exciting the central portion provided on one surface and the other surface of the central portion of the crystal piece;
A lead electrode formed so as to be drawn from each excitation electrode to the peripheral portion on one side of the crystal piece, and fixed to the electrode of the crystal piece support member via a conductive adhesive;
Provided between the excitation electrode provided on one side of the crystal piece at the peripheral edge and the extraction electrode drawn to the one side from the excitation electrode on the other side of the crystal piece, and applied to the extraction electrode A projecting portion for preventing short circuit formed integrally with the crystal piece for preventing the conductive adhesive material from flowing into the excitation electrode;
It is provided with.

  Instead of being provided between the excitation electrode and the lead-out electrode, the short-circuit preventing convex portion is provided between the lead-out electrode and each lead-out electrode in the peripheral portion in order to prevent the conductive adhesive applied to the lead-out electrode from contacting each other. For example, the crystal pieces are rectangular, the lead electrodes are formed at adjacent corners of the crystal pieces, and the short-circuit preventing convex portions are formed at the corners at the outer shapes of the lead electrodes. It is provided along. In addition, in the peripheral part of the crystal piece, in order to adjust the weight distribution in the plane of the crystal piece at each corner adjacent to the corner part where the lead electrodes are formed, the crystal piece is formed integrally with the crystal piece. Further, a convex portion for weight adjustment may be provided.

According to another invention, a crystal piece in which a step is formed in the circumferential direction on one surface and the other surface so that the thickness of the central portion is larger than the thickness of the peripheral portion;
An excitation electrode for exciting the central portion provided on one surface and the other surface of the central portion of the crystal piece;
A lead electrode fixed to the electrode of the crystal piece support member via a conductive adhesive, formed so as to be drawn from each excitation electrode to the peripheral portion on one side of the crystal piece,
With
The extraction electrode and the excitation electrode are formed by sputtering or vapor deposition, and in order to roughen the surface of the extraction electrode, the surface of the peripheral portion on the one surface side is rougher than the surface of the central portion on the one surface side. And

  The extraction electrode is extracted through the side wall of the crystal piece, and in order to roughen the surface of the extraction electrode applied to the side wall, the surface of the side wall may be rougher than the surface of the excitation electrode on one side.

  The crystal resonator of the present invention includes the above-described crystal resonator element, and the electronic component of the present invention includes the crystal resonator.

According to the present invention, on the one surface side of the peripheral portion of the crystal piece, between the excitation electrode provided on the one surface side and the extraction electrode drawn to the one surface side from the excitation electrode on the other surface side of the crystal piece. Are provided with a convex portion for preventing short circuit formed integrally with the crystal piece. Therefore, the conductive adhesive applied to the extraction electrode is suppressed from flowing to the excitation electrode, and normal conductivity between the electrode of the member on which the crystal resonator element is installed and the extraction electrode is impaired. It can be suppressed.
According to another invention, the surface of the peripheral portion on one side of the crystal piece is formed to be rougher than the surface of the central portion on the one side, and the extraction electrode and the excitation electrode are sputtered on the surface of the crystal piece. Or it forms by vapor deposition. Therefore, the roughness of the crystal piece is transferred to the surface of the extraction electrode, and the roughness of the surface of the extraction electrode can be increased. As a result, it is possible to suppress the adhesive material from flowing from the extraction electrode to the excitation electrode, or a short circuit caused by the conductive adhesive material between the extraction electrodes.

(First embodiment)
First, the configuration of the crystal resonator element 2 according to the first embodiment manufactured by the manufacturing method described later will be described. 1 (a) and 1 (b) show the surface and the back surface of the crystal resonator element 2 manufactured by the manufacturing method described later, respectively. As shown in these drawings, the surface of the crystal resonator element 2 The back surfaces are configured to have the same layout. The crystal resonator element 2 is constituted by, for example, an AT-cut rectangular crystal piece 21, and the length of one side of the crystal piece 21 is, for example, 0.3 mm to 3.0 mm.

  Steps 2C and 2D are formed in the circumferential direction on the front and back surfaces of the crystal piece 21, respectively, and the steps 2C and 2D form a rectangular central portion with a large thickness relative to the peripheral edge (bevel portion) 2B. Is formed. In other words, the crystal piece 21 is subjected to a so-called bevel process in which the peripheral edge is thinner than the center. For example, rectangular excitation electrodes 22 and 23 for exciting the central portion are formed on the front and back surfaces of the central portion of the crystal piece 21, respectively, and the central portion is configured as an excitation portion 2A.

  By configuring the peripheral portion 2B so that the height of the peripheral edge portion 2B is lower than the height of the excitation portion 2A, the vibration energy is confined in the excitation portion 2A as described in the background art section, and good characteristics (CI value) are obtained. ). The thickness of the excitation unit 2A is determined according to a desired resonance frequency.

  In the figure, reference numerals 24 and 25 denote extraction electrodes, which are formed integrally with the excitation electrodes 22 and 23 on the front surface and the back surface of the crystal piece 21, respectively. The extraction electrode 24 (25) is extended from the excitation electrode 22 (23) to the outside of the crystal piece 21, and is formed so as to straddle the back surface (front surface) of the crystal piece 22 through the side surface of the crystal piece 21. Yes. The lead electrode 24 (25) is widened in the direction orthogonal to the lead-out direction, and is formed so as to be hooked on the corners of the crystal piece 21 on the front and back surfaces of the crystal piece 21.

  Then, on the front and back surfaces of the peripheral edge 2B of the crystal piece 21, convex portions 26, 27, 28, and 29 are integrally formed with the crystal piece 21 around the lead electrodes 24 and 25 that are widened. Is formed. The term “integrally formed” means that the crystal pieces are not bonded to each other, but are formed by cutting out from one crystal piece. These convex parts 26-29 play the role which prevents the short circuit between electrodes by a conductive adhesive. 1C is a cross-sectional view taken along the line AA ′ in FIGS. 1A and 1B, and FIG. 2 is a diagram of the crystal resonator element 2 viewed from the lead electrodes 24 and 25 side. It is. As shown in these drawings, the heights of the tops of the protrusions 26 to 29 are higher than the heights of the surfaces of the extraction electrodes 24 and 25 formed on the peripheral edge 2B, and the same height as the crystal piece 21 of the excitation part 2A. Is formed.

  Next, a process of forming the above-described crystal resonator element 2 from a wafer W that is a substrate composed of AT-cut quartz will be described. FIG. 3 shows the surface of the wafer W, and regions surrounded by dotted lines in the drawing show element formation regions 31 to 34 where the crystal resonator element 2 is formed. Each element formation region is set as a rectangular region surrounded by line segments parallel to the X axis and the Z ′ axis, which are crystal axes of the wafer W. Actually, the area where the crystal resonator element 2 is formed is set not only in the four areas 31 to 34 but also in the entire device formation area 35 surrounded by a chain line in the figure, which will be described later. Each process is performed on the entire device formation region 35.

  Next, a process of forming the crystal resonator element 2 from the wafer W will be described with reference to FIGS. 4 to 6 show how the vertical cross section of the crystal resonator element formation region 31 indicated by the arrow BB ′ in FIG. 3 changes as each process is performed on the wafer W. FIG. The other element formation regions in the formation region 35 are processed in the same manner as the element formation region 31 and the longitudinal section thereof changes. 4 to 6, the left side and the right side respectively show the + X side and the -X side shown in FIG.

  First, as shown in FIGS. 4A and 4B, the surface of the crystal layer 20 in each element formation region of the wafer W is etched to form a recess 40, and the thickness of the crystal layer 20 in each element formation region is the above-described thickness. It adjusts so that it may become the thickness of the excitation part 2A. FIG. 7A shows the surfaces of the element formation regions 31 to 34 in which the recesses 40 are formed. After the recess 40 is formed, metal films 41 and 42, which are laminated films made of Cr (chromium) on the lower layer side and Au (gold) on the upper layer side, are formed on the front and back surfaces of the wafer W, for example, and then the metal film 41 is formed. , 42 are respectively formed on the resist films 43, 44 (FIG. 4C). For convenience of illustration, the metal films 41 and 42 and each metal film which is a laminated film formed in the same manner as the metal films 41 and 42 are shown as a single film.

  After the resist films 43 and 44 are formed, the resist films 43 and 44 are exposed and developed along the shapes of the excitation portion 2A and the convex portions 26 to 29 formed in the element formation region, and the resist film is developed. Mask patterns 45 and 46 are formed on 43 and 44 (FIG. 4D). FIG. 7B shows the surfaces of the element formation regions 31 to 34 on which the mask pattern 45 is formed. In this figure, for convenience, the remaining resist film 43 is indicated by hatching, and the hatched portion does not indicate a cross section. 8, 9, 12 (b), 18, and 19, which will be described later, the resist film formed on the surface of the wafer W is indicated by hatching in order to make the drawing easier to see. These hatched portions do not indicate a cross section. As shown in FIG. 7B, the resist film 43 remains so as to correspond to the shapes of the excitation portion 2A and the convex portions 26 and 27. Further, the resist film 44 remains on the back surface side of each element formation region so as to have the same layout as that on the front surface side, that is, so as to correspond to the shapes of the excitation portion 2A and the convex portions 28 and 29.

  Subsequently, the metal films 41 and 42 are etched using the resist films 43 and 44 as a mask (FIG. 4E), and an etching solution containing hydrofluoric acid is used using the metal films 41 and 42 as a mask on the front and back surfaces of the crystal layer 20. Using the wet etching, the stepped portions 2C and 2D forming the excitation portion 2A, the peripheral portion 2B, and the convex portions 26 to 29 are formed (FIG. 4F), and then the resist films 43 and 44 and the metal film are formed. 41 and 42 are removed (FIG. 5A). FIG. 8A shows the surface of the wafer W from which the metal films 41 and 42 are thus removed, and the back surface of the wafer W is configured to have the same layout as the front surface.

  Thereafter, metal films 51 and 52 are respectively formed on the front and back surfaces of the crystal layer 20, and resist films 53 and 54 are formed on the metal films 51 and 52, respectively (FIG. 5B). The resist films 53 and 54 are exposed along the outer shape of the crystal piece 21 in each element forming region and then developed, and mask patterns 55 and 56 are formed on the resist films 53 and 54 along the circumference of these element forming regions. (FIG. 5C). FIG. 8B shows the surface of the element formation regions 31 to 34 on which the mask pattern 55 is formed. A mask pattern 56 is also formed on the back surface of the wafer W with the same layout as the mask pattern 55. At this time, resist films 53 and 54 remain on a part of the periphery of each element formation region in order to form a connection portion 60 for connecting and holding the crystal piece 21 to the wafer W when a through-groove described later is formed. doing.

  Thereafter, the metal films 51 and 52 are etched using the resist films 53 and 54 as a mask, and the crystal layer 20 is etched using the metal films 51 and 52 as a mask (FIG. 5D). And the outer shape of the crystal piece 21 constituting the crystal resonator element 2 is formed (FIG. 5E).

  Subsequently, the resist films 53 and 54 and the metal films 51 and 52 are removed (FIG. 6A), and excitation electrodes 22 and 23 and extraction electrodes are formed on the front and back surfaces of the crystal layer 20 so as to straddle the side walls of the through grooves 57. After forming metal films 61 and 62 which are laminated films made of Cr and Au for forming 24 and 25, resist films 63 and 64 are formed so as to cover the metal films 61 and 62 (FIG. 6 ( b)). Thereafter, the resist films 63 and 64 are exposed along a predetermined pattern and developed to form mask patterns 65 and 66 corresponding to the shape of each electrode (FIG. 6C). FIG. 9 shows the resist film 63 remaining after development on the surface of the element formation regions 31 to 34 in the same manner as FIG. 8B by hatching, and the back surface of the wafer W has the same layout as the mask pattern 65. A mask pattern 66 is formed.

  The metal films 61 and 62 are etched along the mask patterns 65 and 66 to form the electrodes 22 to 25 on the crystal piece 21 (FIG. 6D), and the resist films 63 and 64 are removed (FIG. 6E )), The crystal piece 21 is folded from the connecting portion 60 to manufacture the crystal resonator element 2 (FIG. 6F).

  Next, a procedure for manufacturing the crystal resonator 7A by mounting the manufactured crystal resonator element 2 on, for example, the rectangular package 7 will be described with reference to FIG. In the figure, reference numeral 71 denotes a base that forms a substrate of the package 7 that is a crystal piece supporting member, and a space that accommodates the crystal resonator element 2 by the base 71 and the side wall portion 72 provided along the peripheral edge of the base 71. 73 is configured. As shown in FIG. 11A, electrodes 74 and 75 connected to the lead electrodes 24 and 25 of the crystal resonator element 2 are provided on the surface of the base 71. The electrodes 74 and 75 are electrically connected to the electrodes 76 and 77 provided on the lower surface of the base 71 through conductive paths formed in the base 71, respectively. 2 is electrically connected to an electronic component such as a crystal oscillator that is mounted and assembled. In the figure, reference numeral 78 denotes a height adjusting member formed according to the height of the electrodes 76 and 77.

  A conductive adhesive 70 is applied to the electrodes 74 and 75, and the lead electrodes 24 and 25 provided on the back surface side of the crystal resonator element 2 are bonded as shown in FIGS. 10 (b) and 11 (b). The crystal resonator element 2 is fixed to the base 71. FIG. 11C shows the back surface of the crystal resonator element 2 when it is fixed to the base 71 as described above, and the flow of the adhesive 70 is restricted by the projections 28 and 29 as shown in FIG. The adhesive 70 flows out between the extraction electrodes 24 and 25 and between the extraction electrode 24 and the excitation electrode 23, thereby preventing a short circuit between the electrodes. When the crystal resonator element 2 is accommodated in the package 7 in this way, the lid 79 is provided on the upper side of the side wall portion 72, the accommodating space 73 is sealed, and the crystal resonator 7A is manufactured (FIG. 10 ( c)). In place of the lead electrode on the back surface side of the crystal resonator element 2, when the lead electrodes 24 and 25 on the front surface side are connected to the electrodes 74 and 75 via the adhesive 70, the lead electrode on the back surface side is used as the electrode. As in the case of adhering to 74 and 75, the convex portions 26 and 27 restrict the spread of the adhesive material 70 and prevent a short circuit between the electrodes.

  According to the crystal resonator element 2, when wet etching is performed so that the height of the peripheral portion is lower than the height of the excitation portion that is the central portion in order to improve the characteristics, Convex portions 26 to 29 are formed along the periphery. When the lead-out electrodes 24 and 25 are bonded to the electrodes 74 and 75 of the package 7 via the conductive adhesive 70, the spread of the adhesive 70 is restricted by the convex portions 26 to 29. Accordingly, short-circuiting between the elements can be suppressed, so that a normal electrical connection between the crystal resonator element 2 and the electrodes 74 and 75 of the package 7 is ensured. Further, since the convex portions 26 to 29 are formed simultaneously with the steps 2C and 2D, the labor of the manufacturing process is simplified as compared with the case where such steps and the members for preventing the short circuit of the adhesive are formed individually. Can be

  Next, a modification of the crystal resonator element of the first embodiment will be shown. 12 (a) and 12 (b) show the front and back surfaces of the crystal resonator element 3, respectively. FIGS. 12 (c) and 12 (d) show CC ′ in FIGS. 12 (a) and 12 (b). An arrow cross section and a DD ′ arrow cross section are shown. The crystal resonator element 3 has a weight adjusting portion 2E which is a convex portion integrally with the crystal piece 21 on the front and back surfaces of two corner portions where the lead electrodes 24 and 25 are not formed in the peripheral portion 2B. Is formed. Each weight adjusting unit 2E is formed in order to stabilize the oscillation by controlling the weight distribution in the plane of the crystal piece 21. In the above embodiment, the convex portions 26 to 29 are formed at the two corners of the crystal piece 21. It is effective to provide this weight adjusting portion 2E in order to prevent the weight distribution in the surface of the crystal piece 21 from being biased due to the weight of these convex portions 26 to 29 and the vibration being affected. is there.

  The manufacturing method in the case where the weight adjusting unit 2E is formed on the crystal piece 21 will be described. In the first embodiment, the resist films 43 and 44 are exposed according to the shape of the weight adjusting unit 2E to form a mask pattern. To do. Specifically, mask patterns 45 and 46 are formed as shown in FIGS. 12 (a) and 12 (b), respectively, instead of those shown in FIGS. 4 (d) and 7 (b), and the metal films 42, 43, Further, the crystal layer 20 is etched to form the convex portions 26 to 29 and the weight adjusting portion 2E is formed. Thereafter, a series of processes is performed as in the first embodiment. The weight adjusting unit 2E may be formed only on either the front surface or the back surface of the crystal piece 21.

  In the embodiment described above, the protrusions 27 to 29 are provided on the front surface and the back surface of the crystal piece 21. However, in the crystal piece 21, these short-circuit preventions are provided only on the surface fixed by the conductive adhesive 70. A convex portion may be provided. Further, the shape of the convex portions 27 to 29 is not limited to the above example, and may be formed apart from the extraction electrodes 24 and 25, for example.

(Second Embodiment)
The crystal resonator element 8 of the second embodiment will be described. FIGS. 14A and 14B show the front surface and the back surface of the crystal resonator element 8, respectively. FIG. 14C shows a cross section taken along the line EE ′ of the crystal resonator element 8. FIG. . In the crystal resonator element 8, the portions corresponding to the crystal resonator element 2 are denoted by the same reference numerals as those used for the crystal resonator element 2. The difference between the crystal resonator element 8 and the crystal resonator element 2 will be described. The peripheral portions 2B are not provided with the convex portions 26 to 29, and as shown in FIG. Compared with the surface of 2A, the surface of the peripheral part 2B and the surface of the side wall of the crystal piece 21 are rough. Corresponding to the roughness of each surface of the peripheral portion 2B and the side wall, the roughness of the surfaces of the extraction electrodes 24 and 25 is larger than the surface of the excitation electrodes 22 and 23 formed on the excitation portion 2A. The surface roughness of the excitation part 2A is, for example, Ra 0.1 μm to 20 μm, and the surface roughness of the peripheral edge part 2B is larger than that, for example, Ra 20 μm or more.

  Next, a process of forming the crystal resonator element 8 from the wafer W of FIG. 3 will be described with reference to FIGS. 15 to 17 show how the longitudinal section of the element formation region 31 indicated by the arrow BB ′ in FIG. 1 changes as each process is performed on the wafer W as in FIGS. 4 to 6. The other element formation regions are processed in the same manner as the formation region 31 and the longitudinal section thereof changes.

  First, as in the first embodiment, the surface of the crystal layer 20 in each element formation region of the wafer W is wet-etched with a first etching solution to form a recess 40, and the crystal layer 20 in each element formation region is The thickness of the excitation unit 2A is adjusted (FIGS. 15A and 15B). As the first etching solution, for example, a solution containing hydrofluoric acid at 50 ° C. or higher is used so that the surface roughness of the etched crystal layer 20 is suppressed. After the recess 40 is formed, metal films 81 and 82 made of Cr (chromium) and Au (gold) are formed on the front and back surfaces of the wafer W by sputtering, for example, and then the resist film 83 is formed on the metal films 81 and 82, respectively. , 84 are formed (FIG. 15C). For example, the first etching solution is used as the etching solution used in each etching process of the first embodiment.

  Thereafter, the resist films 83 and 84 are exposed along a predetermined pattern and then developed to form mask patterns 85 and 86 on the resist films 83 and 84 (FIG. 15D). FIG. 18A shows the surface of the element formation regions 31 to 34 on which the mask pattern 85 is formed, and the back surface side of each element formation region has the same layout as this surface side, that is, The resist film 84 remains so as to correspond to the shape of the excitation part 2A.

  Subsequently, the metal films 81 and 82 are etched using the resist films 83 and 84 as a mask (FIG. 15 (e)), and the front and back surfaces of the crystal layer 20 are further etched using hydrofluoric acid containing the metal films 81 and 82 as a mask. Wet etching is performed with the etching solution 2. As the second etching solution, for example, a solution containing hydrofluoric acid at 25 ° C. or lower is used so that the surface of the etched crystal layer 20 is rougher than the surface of the masked crystal layer 20. In this example, the first etching solution and the second etching solution have the same composition except that the temperatures are different. By this wet etching, the excitation part 2A and the peripheral part 2B are formed in the crystal piece 21, and the surface of the peripheral part 2B becomes rougher than the surface of the excitation part 2A (FIG. 16A).

  Thereafter, the resist films 83 and 84 and the metal films 81 and 82 are removed (FIG. 16B). Thereafter, metal films 91 and 92 are formed on the front and back surfaces of the crystal layer 20 by sputtering or vapor deposition, respectively. In these metal films 91 and 92, the portion of the peripheral portion 2B is formed so that the surface roughness of the peripheral portion 2B is increased by being affected by the surface roughness of the peripheral portion 2B as compared to the portion of the excitation portion 2A. . Further, resist films 93 and 94 are respectively formed on the metal films 91 and 92 (FIG. 16C). After the resist films 93 and 94 are exposed along the outer shape of the crystal piece 21 in each element formation region, Development is performed, and mask patterns 95 and 96 are formed on the resist films 93 and 94 along the periphery of these element formation regions (FIG. 16D). FIG. 18B shows the surface of the element formation regions 31 to 34 when the mask pattern 95 is formed, and the back surface of the element formation regions 31 to 34 has a layout similar to that of the mask pattern 95. 96 is formed.

  Thereafter, the metal films 91 and 92 are etched using the resist films 93 and 94 as a mask (FIG. 16E), and the crystal layer 20 is etched using, for example, the second etching solution using the metal films 91 and 92 as a mask. A through groove 97 is formed in the crystal layer 20 to form the outer shape of the crystal piece 21 constituting the crystal resonator element 2 (FIG. 17A). By using the second etching solution, the side wall of the through-hole 97, that is, the side wall of the crystal piece 21, is formed to have a larger roughness than the surface of the excitation unit 2A as well as the surface of the peripheral portion 2B.

  Subsequently, the resist films 93 and 94 and the metal films 91 and 92 are removed (FIG. 17B), and excitation electrodes 22 and 23 and extraction electrodes are formed on the front and back surfaces of the crystal layer 20 so as to straddle the side walls of the through grooves 57. Metal films 101 and 102, which are laminated films made of, for example, Cr and Au for forming 24 and 25, are formed by sputtering or vapor deposition. In these metal films 101 and 102, the portion of the crystal piece 21 on the side wall and the peripheral portion 2B corresponds to the surface roughness of the crystal piece 21 as compared with the portion on the excitation portion 2A. Formed.

  Subsequently, resist films 103 and 104 are formed so as to cover the metal films 101 and 102 (FIG. 17C). Thereafter, the resist films 103 and 104 are exposed and developed along a predetermined pattern to form mask patterns 105 and 106 corresponding to the shape of each electrode (FIG. 17D). FIG. 19 shows a mask pattern 105 on the surface of the crystal resonator element formation regions 31 to 34, and a mask pattern 106 having the same layout as the mask pattern 105 is formed on the back surface of the formation region.

  The metal films 101 and 102 are etched along the mask patterns 105 and 106 to form electrodes 22 to 25 on the crystal piece 21 (FIG. 17E), and after the resist films 103 and 104 are removed (FIG. 17F )), The crystal piece 21 is folded from the connecting portion 60 connecting the crystal piece 21 and the wafer W, and the crystal resonator element 8 is manufactured.

  In the manufactured crystal resonator element 8, the extraction electrodes 24 and 25 are fixed to the electrodes 74 and 75 of the package 7 through the conductive adhesive 70 in the same manner as the crystal resonator element 2. 7A is formed. As shown in FIG. 20, since the surface roughness of the lead electrodes 24 and 25 is large, the contact area with the conductive adhesive 70 is larger than when the surface roughness is small, and the electrodes 74 and 75 and the lead electrodes 24 and 25 It is possible to suppress an increase in electrical resistance between the two.

  According to the crystal resonator element 8 of the second embodiment, since the roughness of the extraction electrodes 24 and 25 is larger than that of the excitation electrodes 22 and 23, they are applied to the extraction electrodes 24 and 25, respectively. It is possible to prevent the conductive adhesive 70 from flowing out to a region outside each electrode. Accordingly, it is possible to prevent the lead electrodes 24 and 25 from being short-circuited by the conductive adhesive 70.

  By the way, when the crystal resonator element is downsized as described above, the lead electrodes 24 and 25 are correspondingly reduced, and the contact area between the lead electrodes 24 and 25 and the conductive adhesive 70 tends to be small. When the contact area is reduced in this way, the electrical resistance from the base electrode to each extraction electrode increases, and as a result, the characteristics (CI value) as a crystal resonator element may deteriorate. In this way, when the roughness of the extraction electrodes 24 and 25 is large, the contact area with the conductive adhesive becomes larger than when the roughness is small. As a result, normal conductivity between the extraction electrodes 24 and 25 and the electrodes 74 and 75 of the package 7 is ensured, and an increase in electrical resistance is suppressed. This also has the effect of suppressing the deterioration of the characteristics of the crystal resonator element.

  In the second embodiment described above, the side wall of the crystal piece 21 is also formed by etching so as to increase the roughness similarly to the peripheral portion 2B, so that the side walls of the extraction electrodes 24 and 25 are formed as shown in FIG. Since the roughened portion is also formed with a large roughness, it is preferable because the contact area can be increased even with respect to the conductive adhesive material 70 that wraps around from the back surface to the side surface of the crystal resonator element 8. In the manufacturing process described above, the through groove 97 may be formed before the steps 2C and 2D are formed on the crystal piece 21, or the wafer W is cut in advance to the thickness of the excitation unit 2A, and the step is formed. By forming, it is not necessary to adjust the thickness of the crystal layer 20 with the first etching solution shown in FIGS. 4 (a) (b) and 15 (a) (b).

  In the above example, the surface roughness of the crystal is controlled by using a solution containing hydrofluoric acid having different temperatures between the first etching solution and the second etching solution, but different compositions are used instead of different temperatures. By using an etching solution having the above, the surface roughness of the excitation portion 2A and the surface roughness of the peripheral edge portion 2B may be controlled differently. Further, the second embodiment is applied to the first embodiment, and in the manufacturing process of the first embodiment, etching is performed along the mask patterns 45 and 46 using the second etching solution, and the crystal is crystallized. In forming the step in the piece 21, the surface of the peripheral edge 2B may be roughened, and the side wall of the crystal piece 21 may be roughened using the second etching solution when forming the through groove 57. Good.

  In each of the above-described embodiments, the crystal piece 21 is preferably used that is AT-cut as described above because of excellent vibration characteristics and temperature characteristics, but the crystal used in the present invention is limited to the AT-cut. is not. Further, the shape of the crystal piece 21 is not limited to a rectangle, but may be a circle.

1 is a configuration diagram of a crystal resonator element according to a first embodiment of the invention. FIG. It is a side view of the element for crystal oscillators. 2 is a surface view of a wafer W on which the crystal resonator element is formed. FIG. FIG. 4 is a process diagram for manufacturing a crystal resonator element from the wafer. FIG. 4 is a process diagram for manufacturing a crystal resonator element from the wafer. FIG. 4 is a process diagram for manufacturing a crystal resonator element from the wafer. FIG. 3 is a surface view of a crystal resonator element formation region provided on the wafer. FIG. 3 is a surface view of a crystal resonator element formation region provided on the wafer. FIG. 3 is a surface view of a crystal resonator element formation region provided on the wafer. FIG. 5 is a process diagram for manufacturing a crystal resonator element by mounting the crystal resonator element on a package. It is explanatory drawing which showed the mode of the electroconductive adhesive material in the said package. It is the block diagram which showed the modification of the element for 1st crystal oscillators. It is a block diagram of the element for crystal oscillators concerning the 2nd Embodiment of this invention. FIG. 4 is a process diagram for manufacturing a crystal resonator element from the wafer. FIG. 4 is a process diagram for manufacturing a crystal resonator element from the wafer. FIG. 4 is a process diagram for manufacturing a crystal resonator element from the wafer. FIG. 3 is a surface view of a crystal resonator element formation region provided on the wafer. FIG. 3 is a surface view of a crystal resonator element formation region provided on the wafer. It is a vertical side view of the package which mounts the element for crystal oscillators. It is a block diagram of the element for conventional crystal oscillators. It is explanatory drawing which showed the conductive adhesive which short-circuits the electrode of the said element for crystal oscillators.

W Wafer 2A Excitation part 2B Peripheral part 2,8 Crystal oscillator element 21 Crystal piece 22, 23 Excitation electrodes 24, 25 Extraction electrodes 26-29 Convex parts 31-34 Crystal oscillator element formation region 7 Package 70 Conductive bonding Material 71 Base 74-77 Electrode

Claims (4)

A crystal piece in which a step is formed in the circumferential direction on one surface and the other surface so that the thickness of the central portion is larger than the thickness of the peripheral portion;
An excitation electrode for exciting the central portion provided on one surface and the other surface of the central portion of the crystal piece;
A lead electrode fixed to the electrode of the crystal piece support member via a conductive adhesive, formed so as to be drawn from each excitation electrode to the peripheral portion on one side of the crystal piece,
With
The extraction electrode and the excitation electrode are formed by sputtering or vapor deposition, and in order to roughen the surface of the extraction electrode, the surface of the peripheral portion on the one surface side is rougher than the surface of the central portion on the one surface side. A crystal resonator element.   The lead electrode is drawn through a side wall of a crystal piece, and the surface of the side wall is rougher than the surface of the excitation electrode on one side in order to roughen the surface of the lead electrode applied to the side wall. Item 4. The crystal resonator element according to Item 1.   A crystal resonator comprising the crystal resonator element according to claim 1.   An electronic component comprising the crystal resonator according to claim 3.

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