JP5929244B2 - Thickness-slip vibration type crystal piece, thickness-shear vibration type crystal piece with electrode, crystal diaphragm, crystal resonator and crystal oscillator - Google Patents

Description

  The present invention relates to a thickness-shear vibration type crystal piece, and more specifically, has a crystal piece portion formed into a rectangular shape by etching on a crystal substrate, and a vibration mode by piezoelectric action of the crystal piece portion is a thickness-shear vibration. The present invention relates to a thickness-shear vibration type crystal piece that is a mode.

  The present invention also relates to a thickness-shear vibration type crystal piece with an electrode using the crystal piece, a crystal vibration plate, a crystal resonator, and a crystal oscillator as a related technology of the thickness-shear vibration type crystal piece.

  In the present invention, in particular, both the prevention of excessive etching erosion and the separability of the quartz piece from the quartz substrate are achieved, thereby improving the shape accuracy of the rectangular quartz crystal plate obtained by the separation and improving the vibration characteristics. It is related with the technique for improving.

  The thickness shear vibration mode is a mode that vibrates so that both the front and back surfaces in the thickness direction of the quartz crystal plate slide in opposite directions, and is used for a high-frequency vibrator. In this mode of the crystal diaphragm, the vibration frequency is inversely proportional to the thickness of the crystal diaphragm. The thickness-shear vibration mode is typified by an AT-cut quartz diaphragm, but an SC-cut quartz diaphragm is also applicable.

  An AT-cut crystal diaphragm, which is a typical example of a thickness-shear vibration mode crystal diaphragm, will be described. Quartz has crystal axes of X axis (electrical axis), Y axis (mechanical axis), and Z axis (optical axis). The Y-cut is performed so that the main surface is orthogonal to the Y-axis. The AT cut is performed by cutting a cut surface rotated by a certain angle around the X axis with reference to the cut surface of the Y cut. The rotation direction of the constant angle rotation is a direction in which the Y axis approaches the Z axis, and the rotation angle θ is generally set to 35 ° 15 ′. Note that this is the case of the right crystal, and in the case of the left crystal, the Z-axis is rotated in a direction approaching the Y-axis. The state of AT cut will be described with reference to FIG.

  In FIG. 15A, a Y-cut is drawn with a thin line. This Y-cut crystal diaphragm is a rectangular parallelepiped (three parallel two surfaces are perpendicular to each other), and its main surface is rectangular. The crystal axes of the Y-cut quartz diaphragm are the X-axis, Y-axis, and Z-axis, and the main surface is orthogonal to the Y-axis. This Y-cut quartz diaphragm has a relatively large frequency change with respect to temperature change. Therefore, an AT-cut quartz diaphragm has been adopted in order to reduce the frequency change with respect to the temperature change near room temperature.

  In FIG. 15A, the AT cut is drawn with a thick line. The AT cut is performed with a cut surface rotated by a fixed angle θ (= 35 ° 15 ′) around the X axis in a direction to bring the Z axis closer to the Y axis with reference to the cut surface of the Y cut.

  The three-dimensional axes of this AT cut are the original X axis, the rotated Y ′ axis, and the rotated Z ′ axis. This AT-cut quartz diaphragm is also a rectangular parallelepiped, and its main surface is orthogonal to the Y ′ axis. “Rectangle” means a right-angled quadrilateral including a rectangle and a square. In the case of a rectangular AT-cut quartz diaphragm, the X-axis direction is usually the long-side direction and the Z′-axis direction is the short-side direction. AT-cut quartz diaphragms are widely used because the temperature characteristics of vibration frequency are very stable.

  By the way, the AT-cut quartz crystal diaphragm has been recently produced by using a photolithography technique and wet etching instead of the conventional dicing method due to the progress of ultra-miniaturization and mass production. When producing by photolithography technology and wet etching, the problem is excessive etching erosion (over-etching).

  In the AT cut quartz crystal plate and the SC cut quartz crystal plate, the etching rate differs in the X-axis direction, the Y′-axis direction, and the Z′-axis direction because of etching anisotropy.

  The etching rate in the Z′-axis direction is the largest, followed by the etching rate in the + X-axis direction, the etching rate in the −X-axis direction, and the etching rate in the Y-axis direction. Here, the etching rate in the + X-axis direction is an etching rate in a direction from + X toward -X.

  As a result of the excessive erosion of etching, the outer shape of the AT-cut quartz diaphragm is as shown in FIG. A large taper on the positive side of the X-axis, the negative side of the Y′-axis, the positive side of the Z′-axis, and the positive side of the X-axis, the positive side of the Y′-axis, and the vertex J on the negative side of the Z′-axis. Etching excessive erosion S1, S2 occurs. Etching excessive erosion S1 on the first main surface has an elongated triangular shape along the ridge line HN, and etching excessive erosion S2 on the second main surface has an elongated triangular shape along the ridge line JU. Further, although small, the vertex N on the negative side of the X axis, the negative side of the Y ′ axis, and the positive side of the Z ′ axis, and the vertex U on the negative side of the X axis, the positive side of the Y ′ axis, and the negative side of the Z ′ axis. However, excessive etching erosion S3 and S4 occurs.

  When excessive erosion of these etchings occurs, the outer shape of the quartz diaphragm is deteriorated, the vibration region is reduced, and the vibration characteristics are deteriorated.

  The thickness of the thickness-shear vibration mode crystal plate is determined by the thickness (thickness and frequency are inversely proportional). However, if the ratio of excess erosion on the front and back main surfaces becomes relatively large, the thickness becomes insufficient. Adversely affects vibration characteristics. The smaller the size, the greater the impact. Further, the frequency deviation per unit thickness increases as the frequency increases. Therefore, it is important to suppress the excessive etching of etching at the corners of the rectangular crystal piece as much as possible.

JP 2010-4484 A JP 2007-142526 A JP 2008-92505 A JP 2010-178320 A JP 2011-19213 A JP 2011-139532 A

  The problem of deterioration in vibration characteristics due to excessive etching erosion described above is unavoidable when manufacturing a thickness-sliding quartz diaphragm (especially an AT-cut quartz diaphragm) using photolithography and wet etching. .

  In an AT-cut quartz crystal plate manufactured by wet etching, the vibration characteristics are greatly deviated from the design value due to excessive erosion of the taper-shaped etching that is greatly expressed on the X axis plus side.

  In addition, when miniaturization is performed, the chip volume is largely lacking, which causes a difficulty in handling.

  Until now, various proposals have been made to solve such problems, and the present invention is also positioned as a part thereof.

  FIGS. 16A and 16B show two methods of supporting the crystal piece portion in a cantilevered manner with respect to the support frame portion of the wafer body.

  In FIG. 16A, the + X direction is downward, and in FIG. 16B, the + X direction is upward. FIG. 16A shows a method in which the center portion of the short side portion 1a on the negative side of the X-axis of the crystal piece 1 is supported in a cantilever manner on the support frame portion 2 of the wafer body via the connecting portion 3 for separation. FIG. 16B shows a cantilevered support of the central portion of the short side portion 1b on the X-axis plus side of the crystal piece portion 1 with respect to the support frame portion 2 of the wafer body via the connecting portion 3 for separation. The method that was made to show.

  In FIG. 16 (a), large etching excessive erosion S1 and S2 occurs at the free end side (X-axis plus side) far from the separation connecting portion 3 among the both ends in the long side direction of the crystal piece 1. Yes.

  On the other hand, in FIG. 16B, large etching excessive erosion S1 and S2 occurs at the fixed end side (X-axis plus side) closer to the separation connecting portion 3 among the both ends in the long side direction of the crystal piece 1. Has occurred.

  According to Patent Document 1 (Japanese Patent Laid-Open No. 2010-4484), FIG. 16 (a) is an old method and FIG. 16 (b) is a new method. As common general knowledge in the technical field of thickness-slip quartz crystal plates, an excitation electrode is formed on the X-axis plus side (extraction electrode is formed on the X-axis minus side), and the X-axis plus side of the crystal piece is used as a vibration region. If used, it is said that the characteristics of the quartz diaphragm can be exhibited best.

  In the crystal piece 1 in FIG. 16A, it is planned to form an excitation electrode on the X-axis plus side and an extraction electrode on the X-axis minus side. However, wet etching has etching anisotropy with respect to quartz, and the etching rate from the X-axis plus side to the X-axis minus side is larger than the etching rate from the X-axis minus side to the X-axis plus side. Therefore, so-called etching excessive erosion occurs in which the etching proceeds fast at the corner on the X axis plus side, and an eroded portion is formed. The change in the external shape of the crystal piece affects the temperature characteristics of the frequency, but if an erosion part is formed at the corner of the crystal piece on the excitation electrode side, the temperature characteristic of the planned frequency cannot be obtained. .

  The smaller the crystal piece, the greater the proportion of the erosion part on the crystal piece, and the greater the influence of the erosion part. Furthermore, if the crystal piece has a distorted shape, scratches and the like are likely to occur before the crystal diaphragm is handled and mounted on the base of the package, and thus there is a high risk of being a defective product.

  Therefore, in the technique disclosed in Patent Document 1, the countermeasure shown in FIG. That is, the short side portion 1b on the X axis plus side is supported by the support frame portion 2 by the separation connecting portion 3. Here, it is planned that an excitation electrode is formed in the central portion of the crystal piece and an extraction electrode is formed on the X axis plus side. The lead electrode is formed on the side close to the support frame portion 2 and the separation connecting portion 3, and the excitation electrode is formed on the free end side far from the support frame portion 2 and the separation connecting portion 3, as shown in FIG. It is common to (b).

  In the case of FIG. 16B, excessive etching erosion occurs on the X-axis plus side, which is the side close to the support frame portion 2 and the separation connecting portion 3. The region where excessive erosion occurs is a region where the extraction electrode is formed. On the other hand, there is little erosion on the free end side far from the support frame portion 2 and the separation connecting portion 3, and an excitation electrode is formed in that region. That is, the vibration region of the crystal piece portion is a region with less erosion, and as a result, the adverse effect on the frequency temperature characteristic is sufficiently suppressed. For this reason, in the technique of Patent Document 1, it is said that good characteristics of the crystal diaphragm can be obtained when the outer shape of the crystal piece is formed by wet etching.

  In the technique disclosed in Patent Document 2 (Japanese Patent Application Laid-Open No. 2007-142526), both ends of the X-axis plus side end of the crystal piece portion are connected to the crystal substrate (wafer body) via a separation connecting portion (support portion). It is integrally connected in a cantilever state. The separation connecting portion is formed such that the outer surface thereof is flush with the outer surface of the quartz substrate. It is said that there is no stagnation (trigger) that causes etching excessive erosion due to the continuous surface form of both outer side surfaces, and that etching erosion does not occur despite etching anisotropy. Further, it is said that a groove is formed outward in the Z′-axis direction in the separation connecting portion, so that it is easy to separate the crystal piece from the wafer body. The same applies to Patent Document 6 (Japanese Patent Laid-Open No. 2011-139532).

  In Patent Document 3 (Japanese Patent Laid-Open No. 2008-92505), the outer side surfaces of the pair of separation connecting portions at both ends of the crystal piece portion in the Z′-axis direction are continuously formed along the side surfaces of the crystal piece portion. Yes.

  In Patent Document 4 (Japanese Patent Application Laid-Open No. 2010-178320), a pair of integrally formed parts for connection with a frame part at both ends in the Z′-axis direction at the base end part on the X-axis plus side of the crystal diaphragm. A groove for separation is formed in the separation connecting portion. The groove in one separation connecting portion and the groove in the other separation connecting portion are arranged on opposite surfaces in the front-back direction (Y ′ direction). That is, one is the plus side of the Z ′ axis of the plus main surface of the Y ′ axis, and the other is the minus side of the Z ′ axis of the minus main surface of the Y ′ axis.

  In Patent Document 5 (Japanese Patent Application Laid-Open No. 2011-19213), apart from the connecting portion for separation, a protrusion extending in the + X direction at both ends in the Z′-axis direction at the base end portion on the X-axis plus side is a crystal piece. Etching is performed using a mask that spans between the frame portion and the frame portion. The protrusion is separated from the frame after etching.

  As described above, various proposals have been made so far to solve the above-mentioned problems, but regarding the coexistence of prevention of excessive etching erosion and ensuring separation of the crystal piece from the crystal substrate, In fact, what is fully satisfactory has not been developed yet.

  The present invention has been created in view of such circumstances, and as described at the beginning, it is possible to achieve both the prevention of excessive etching erosion and the separability of the crystal piece from the crystal substrate, thereby achieving separation. The object is to improve the vibration characteristics by improving the shape accuracy of the obtained quartz diaphragm.

  In order to solve the above problems, the present invention takes the following measures.

  (1) The present invention is directed to a thickness-shear vibration type crystal piece in which a rectangular crystal piece portion is integrally connected to a support frame portion by wet etching with respect to a crystal substrate. Here, “rectangular” means a right-angled quadrilateral including a rectangle and a square.

  The vibration mode in the thickness-shear vibration type crystal piece is a vibration mode in which the front and back main surfaces in the thickness direction of the crystal piece portion vibrate so as to slide in opposite directions along the surface direction. The thickness shear vibration type crystal piece includes an AT cut and an SC cut as a cut type for the crystal. The AT cut is performed by cutting a cut surface rotated by a certain angle around the X axis with reference to the cut surface of the Y cut that is cut so that the main surface is orthogonal to the Y axis. The SC cut is performed by cutting a plane orthogonal to the Y axis of the crystal by a fixed angle around the X axis and further rotating by a fixed angle around the Z axis.

  A feature of the present invention resides in that the separation connecting portion is configured as follows on the premise of the crystal piece.

  Here, the virtual corner of the rectangular crystal piece is defined.

  In wet etching, the virtual corner portion does not actually appear as a corner portion, but is buried in a continuous region between the crystal piece portion and the separation connecting portion.

  In the separation connecting portion, when the quartz crystal piece is separated from the support frame portion (more specifically, separated from the separation coupling portion) and the rectangular quartz piece is taken out, a corner portion is generated in the rectangular quartz piece. It will be. A portion corresponding to the corner portion that is generated by this separation is referred to as a virtual corner portion before the completion of the wet etching.

  In the present invention, at least one imaginary corner portion in the Z′-axis direction (lateral direction) at the base end portion on the X-axis plus side of the crystal piece portion and the vicinity thereof are applied to the disposing portion of the separation connecting portion. ing. Here, the Z′-axis direction is an axis inclined from the Z-axis of the main surface in the above-described cutting.

  Further, at least one separation connecting portion is configured to cover the virtual corner portion of the crystal piece portion from two directions substantially at a right angle. A mask pattern that satisfies the above conditions is formed when the quartz substrate is wet etched to form the outer shapes of the plurality of rectangular crystal pieces, the support frame, and the separation connecting portion.

  More specifically, it is as follows.

  The surface obtained by extending the outer surface of the Z′-axis direction end portion of the crystal piece portion to the virtual corner portion is defined as the virtual side surface, and the surface obtained by extending the base end surface on the X axis plus side of the crystal piece portion to the virtual corner portion is defined as the virtual base end surface. To do. The virtual side surface and the virtual base end surface intersect at a right angle at the virtual corner portion. When creating a rectangular crystal piece by separating the rectangular crystal piece from the support frame at the separation connecting portion, the virtual side surface and the virtual base end surface that is perpendicular to the virtual side surface are separated as a boundary surface. I plan to do that. The at least one separation connecting portion is configured to be integrally connected to the crystal piece portion while covering the virtual side surface and the virtual base end surface continuous at right angles to the virtual side surface from the outside.

  This will be described with reference to FIG. FIG. 1 is a conceptual diagram for use in understanding the basic configuration of a crystal piece according to the present invention. A surface obtained by extending the outer surface A of the rectangular crystal piece 1 to the X-axis plus side (the separation connecting portion 3 side) is a virtual side surface K1 (refer to a light-colored hatching region).

  Further, a surface obtained by extending the base end surface E of the crystal piece 1 along the Z-axis direction to the separation connecting portion 3 side is a virtual base end surface K2 (see a light-colored hatching region).

  Virtual corners Q1 and Q2 are the points where the intersecting line between the virtual side face K1 and the virtual base end face K2 intersects the main surfaces of the front and back surfaces of the crystal piece 1.

  When the rectangular crystal piece 1 is formed by separating the rectangular crystal piece 1 from the support frame 2 in the separation connecting portion 3, the virtual side face K1 and the virtual base end face K2 may be separated as a boundary surface. is planned.

  The separation connecting portion 3 is integrally connected to the crystal piece portion 1 and the support frame portion 2 while covering the virtual side face K1 of the crystal piece portion 1 and the virtual base end face K2 continuous at right angles thereto. It has become a form.

  As shown in the figure, the virtual side face K1 and the virtual base end face K2 connected perpendicularly to the virtual side face K1 are buried in the continuous region between the crystal piece 1 and the separation connecting part 3, and are not exposed to the outside.

  The configuration of FIG. 1 is useful for conceptually understanding the technical features of the present invention. Of course, the gist of the present invention itself is not particularly restricted by the illustrated configuration.

  In the crystal piece having the above-described configuration, the etching mask for wet etching is masked so that the crystal piece portion, the support frame portion, and the separation connecting portion are etched in the above-described form of the present invention. Wet etching is performed. The virtual corner portion of the base end portion on the X axis plus side of the crystal piece portion is in a state in which the separation connecting portion forms a right angle and covers from two directions, and the etching solution does not act on the virtual corner portion itself.

  Referring to FIG. 1, in the vicinity of the virtual corners Q1 and Q2 existing in the continuous region of the crystal piece 1 and the separation connecting portion 3, the outer surface A of the crystal piece 1 and a right angle thereto. Focusing on the boundary with the longitudinal side surface B of the connecting portion 3 for separation, the boundary is a concave ridge line R1, and the concave ridge line R1 faces the virtual side surface K1.

  In the substantial part of the crystal substrate including the crystal piece 1 facing the concave ridge line R1 and the separating connection part 3, there are no sharp corners (vertices perpendicular to each other in the three-dimensional direction). The expansion range of the substantial part on the main surface is large, corresponding to 3 right angles (270 °), and the trigger of excessive etching erosion is not formed.

  By the way, there are convex corner portions P3 and P4 in the portion of the separation connecting portion 3 away from the concave ridgeline R1, and there is a possibility that an excessive erosion trigger of etching is formed here. However, the place is away from the virtual side face K1 and the virtual base end face K2, and does not face these faces. Therefore, it does not matter if excessive etching erosion occurs at the convex corners P3 and P4.

  On the inner side of the connecting portion 3 for separation, the boundary between the base end surface E and the lateral side surface F continuous at right angles thereto is a concave ridgeline R2, and the concave ridgeline R2 faces the virtual base end surface K2. . Even in the substantial part of the crystal substrate including the crystal piece 1 and the separation connecting part 3 facing the concave ridgeline R2, there are no sharp corners (vertices perpendicular to each other in the three-dimensional direction). The expansion range of the substantial part on the main surface is large corresponding to 3 right angles (270 °), and the trigger of excessive etching erosion is not formed.

  In summary, the thickness-shear vibration type crystal piece according to the present invention includes a rectangular crystal piece formed by etching on a crystal substrate, a support frame portion that supports the crystal piece, and the crystal piece. A separation connecting portion for connecting the crystal frame portion to the support frame portion, wherein the crystal piece portion is driven in a thickness-shear vibration mode, and the separation connection portion is configured to have an X-axis (electrical axis) of the crystal crystal axis. Axis) is arranged at at least one corner in the Z′-axis direction which is a base end portion of the crystal piece portion on the plus side and is an axis inclined from the Z-axis (optical axis) of the crystal crystal axis, and In the connecting part for separation, a virtual side surface obtained by virtually extending the outer surface of the Z′-axis direction end portion of the crystal piece portion in the X-axis direction and a base end surface on the X-axis plus side of the crystal piece portion are set in the Z′-axis direction. Is configured to continuously cover the virtual base end surface virtually extended from the outside. It is characterized in that there.

  The effect | action by the said structure of this invention is as follows.

  The thickness slip of the present invention in which the crystal piece portion is integrally connected to the support frame portion with a connecting portion for separation in such a form as to cover the virtual corner portion of the rectangular crystal piece portion and its vicinity from two directions perpendicular to each other. In the vibration type crystal piece, in the rectangular crystal piece portion that is manufactured by separating the crystal piece portion from the support frame portion in the separation connecting portion, excessive erosion of etching is caused at the corner on the X axis plus side. Therefore, a rectangular crystal piece having excellent shape accuracy can be obtained.

  In addition, the outer side surface of the crystal piece portion and the longitudinal side surface of the separation connecting portion intersect at right angles so as to form a concave ridge line (R1), and the base end surface of the crystal piece portion and the lateral direction of the separation connection portion The side surfaces intersect at a right angle so as to form a concave ridgeline (R2). In this configuration, when creating a rectangular crystal piece, when separating the crystal piece from the support frame at the connecting part for separation, the virtual corners of the crystal piece are separated with high accuracy at right angles as planned. It will be a machine. That is, separation of the crystal piece portion from the support frame portion in a state having high shape accuracy is facilitated, and a rectangular crystal piece portion with good shape accuracy is obtained.

  That is, according to the present invention, combined with prevention of excessive etching erosion on the X-axis plus side and ensuring the ease of separation of the crystal piece, the shape accuracy of the rectangular crystal piece to be obtained by the separation can be improved. It becomes possible to improve the vibration characteristics.

  The above invention can be developed as follows.

  As described above, the separation connecting portion characterized in the present invention continuously covers the virtual side surface and the virtual base end surface of the crystal piece portion from the outside. In addition to being arranged not only at one imaginary corner of one piece, there is a mode of being arranged at each corner at both ends in the Z′-axis direction, and a crystal piece having a separation connecting portion arranged at both ends is typical. It is assumed. In the case where a pair of connecting portions for separation in the form of continuously covering the virtual side surface and the virtual base end surface of the crystal piece from the outside are provided at the corners on both ends in the Z′-axis direction, the shape of the separation is compared to the case where they are provided only at one end The accuracy is greatly improved. Further, it is effective in securing the stability of the support of the crystal piece with respect to the support frame and preventing the crystal piece from being accidentally dropped due to vibration or impact when the crystal piece is handled.

  About the connection length with respect to the crystal piece part of the said connection part for isolation | separation, there exists the following aspect. Referring to FIG. 1, the connection length L2 (Q1 at the virtual base end face K2 virtually extended from the connection length L1 (P1-Q1 length) at the virtual extension virtual side surface K1 described above. -P5 length) (L1 <L2).

  This aspect is effective when separation of the crystal piece portion from the support frame portion in the separation connecting portion is important for ease of separation. In this case, the connection length L1 at the virtual side face K1 is the same as the connection length L2 at the virtual base end face K2 (L1 = L2) or longer than that (L1> L2). Thus, the shape accuracy of the rectangular quartz piece obtained by the separation and the flatness accuracy of the separation surface become higher.

  Or, conversely, the connection length L1 at the virtually extended virtual side surface K1 is equal to or longer than the connection length L2 at the virtually extended virtual base end surface K2. There are aspects.

  This aspect works effectively when importance is attached to the strength of the support of the crystal piece portion by the support frame portion via the separation connecting portion. In particular, this is effective in preventing the unexpected dropout of the rectangular crystal piece due to vibration or shock when handling the crystal piece. This is particularly effective in the case of a rectangular crystal piece whose length in the X-axis direction is longer than the length in the Z′-axis direction. This is because it is reasonable to support the longer side portion with the longer connecting portion.

  Moreover, about the thickness of the connection part for isolation | separation, there exists an aspect comprised thinly than the thickness of a crystal piece part and a support frame part. For this purpose, the back side of the separation connecting part is a recess and the front side is flush with the main surface of the crystal piece, or conversely the front side of the separation connecting part is a recess. There is a form in which the back side is flush with the back side main surface of the crystal piece part, and further, both the front and back sides of the separation connecting part are recessed.

  By making the thickness of the connecting part for separation thinner than the thickness of the crystal piece part and the support frame part, it becomes easier to separate the crystal piece part from the support frame part in the connecting part for separation, and the shape of the rectangular crystal piece part This is advantageous in increasing the accuracy.

  Further, in order to ensure the right angle accuracy of the corner when separating the crystal piece from the support frame in the separation connecting portion, the separation is facilitated in the integral connection region of the crystal piece and the separation connecting portion. There exists an aspect which forms the separation assistance part for this.

  This separation support unit has an action of reducing a resistance (resistance) to an applied force at the time of separation. Referring to FIG. 1, the connection region is a region in the vicinity of a right-angle separation planned surface that is continuous from the virtual side surface K1 to the virtual base end surface K2.

  There are various forms of the separation support unit.

  It is good also as a ditch | groove formed in the state which continued at right angles along the integral connection area | region of the said crystal | crystallization piece part and the connection part for isolation | separation, or it is good also as several groove | channels formed at intervals in the connection area | region. It may be a recess. The opening intervals may be equal intervals or unequal intervals. About the arrangement position of the separation support part with respect to the main surface of the crystal piece part, it may be formed on both the front and back sides of the connecting part for separation, may be formed only on the front side, or formed only on the back side There is also. Furthermore, there is also a form in which the separation supporting unit is configured with a plurality of through holes formed at intervals in the connection region.

  Further, regarding the intensity distribution with respect to the separation support unit, the intensity is highest at the virtual corner portion of the crystal piece portion that changes the direction from the X-axis direction to the Z′-axis direction in the connection region, and the strength increases as the distance from the virtual corner portion increases. There is a mode of gradually lowering. If comprised in this way, isolation | separation from the support frame part of the crystal piece part in the connection part for isolation | separation will be made easier, and it will act advantageously in making shape accuracy of a rectangular crystal piece part higher.

  Furthermore, there may be a mode in which the crystal piece portion is integrally connected to the support frame portion via another separation connecting portion at the X-axis minus side end portion of the crystal piece portion. This is suitable for enhancing prevention of falling off during handling.

  (2) The present invention also has a technical object of a thickness-shear vibration type crystal piece with electrodes in a form in which the thickness-shear vibration type crystal piece is further technically developed. The thickness-shear vibration type crystal piece with an electrode according to the present invention is a thickness-shear vibration type crystal piece having any one of the above-described structures, and an excitation electrode formed to face the center portions of the front and back surfaces of the crystal piece part, The lead electrode is formed on the X-axis plus side edge on both the front and back surfaces of the crystal piece while being electrically connected to the front and back excitation electrodes.

  In this thickness-shear vibration type crystal piece with electrodes, the crystal vibration that can be obtained by separation in combination with prevention of excessive etching on the X-axis plus side and ensuring the ease of separation of the crystal piece portion. It has the characteristics of improving the shape accuracy of the plate and improving its vibration characteristics. Therefore, the thickness-shear vibration type crystal piece with electrodes according to the present invention is excellent in shape accuracy and exhibits high-quality vibration characteristics.

  Further, as another aspect of the thickness-shear vibration type crystal piece with electrodes, in the state of being electrically connected to the excitation electrode formed opposite to the center part of both the front and back surfaces of the crystal piece portion and the front and back excitation electrodes There is also an aspect in which both the front and back surfaces of the crystal piece portion are provided with extraction electrodes formed on the outer surface edge of the end portion in the Z′-axis direction. In the case of this aspect, it is possible to increase the distance between the pair of extraction electrodes. The rectangle that is the shape of the crystal piece is often a rectangle whose long side is along the X-axis direction. The outer side surface of the rectangular crystal piece is longer than the base end surface (along the short side), and has a larger space with respect to the arrangement of the extraction electrodes. Therefore, as described above, the configuration in which the pair of extraction electrodes are arranged on the outer side surface of the crystal piece portion makes it possible to widen the distance between both extraction electrodes, and as a result, the conductive bonding material applied to each extraction electrode Interference (such as a short circuit) can be suppressed.

  The present invention is not limited to the case where the long side is a rectangle along the Z′-axis direction in addition to the case where the long side is a rectangle along the Z′-axis direction, or the two right-angle sides are equal in length. This includes the case of a square.

  (3) The present invention also includes a quartz crystal diaphragm. The crystal diaphragm according to the present invention is obtained by separating the crystal piece portion of the thickness-shear vibration type crystal piece with electrodes having the above-described configuration from the support frame portion at the separation connecting portion. The quartz crystal diaphragm according to the present invention is excellent in shape accuracy and exhibits high quality vibration characteristics.

  (4) The present invention also provides a crystal resonator. A crystal resonator according to the present invention includes a crystal diaphragm having the above-described configuration, a package that accommodates the crystal diaphragm, and a conductive bonding material that mechanically and electrically joins an extraction electrode in the crystal diaphragm and a pad electrode in the package. The package is hermetically sealed. The crystal resonator according to the present invention is excellent in shape accuracy and exhibits high quality vibration characteristics. Here, the conductive bonding material includes a hardened paste-like conductive adhesive, a metal brazing material such as lead-free solder, a metal bump, and the like. The metal bump is, for example, a gold (Au) stud bump or a gold thick film (plated film or the like), and is joined by ultrasonic waves.

  (5) The present invention also provides a crystal oscillator. The crystal oscillator includes the crystal diaphragm, an integrated circuit including an oscillation circuit for exciting and driving the crystal diaphragm, and a package for housing the crystal diaphragm and the integrated circuit. In this crystal oscillator, the crystal diaphragm has excellent shape accuracy and exhibits high quality vibration characteristics. The crystal diaphragm and the integrated circuit may be stored in the same space in one package, or may be stored in different spaces.

  As described above, according to the present invention, it is possible to achieve both prevention of excessive etching erosion on the X-axis plus side and ensuring separation ease of the crystal piece, and the rectangular crystal piece to be obtained by separation or It is possible to improve the shape accuracy of the quartz diaphragm and improve its vibration characteristics.

Conceptual diagram (perspective view) for use in understanding the basic configuration of the thickness-shear vibration crystal piece of the present invention Plan view of quartz substrate and thickness-shear vibration type quartz piece in Example 1 of the present invention The enlarged plan view of one division part in Example 1 of the present invention Process sectional drawing of thickness adjustment of the crystal piece part in Example 1 of this invention Process sectional drawing of the external shape formation of the crystal piece part in Example 1 of this invention Process sectional drawing of the electrode formation in Example 1 of this invention The top view of the thickness shear vibration type crystal piece with an electrode in Example 1 of this invention Conceptual diagram (perspective view) for use in understanding the basic configuration of the crystal piece in the second embodiment of the present invention The enlarged plan view of one division part in Example 2 of the present invention, and also the enlarged plan view of the part Explanatory drawing (plan view) of the separation support unit in another embodiment of the present invention Plan view of a thickness-shear vibration type crystal piece with electrodes in another embodiment of the present invention The enlarged plan view of the one division part in the other Example of this invention (the 1) The top view and side view of a rectangular crystal piece in another embodiment of the present invention The enlarged plan view of the one division part in the other Example of this invention (the 2) Explanatory drawing of AT cut in conventional technology The top view which shows how to make the cantilevered support of the crystal piece part with respect to the support frame part of the wafer main body in a prior art

  Hereinafter, a thickness-shear vibration type crystal piece and related technology according to an embodiment of the present invention will be described in detail with reference to the drawings.

Example 1
In FIG. 2, 11 is an AT-cut quartz substrate (quartz wafer), 11 a is an orientation flat for specifying the crystal direction formed on a part of the peripheral portion of the quartz substrate 11, and 12 is a plurality of rectangular shapes on the quartz substrate 11. It is a section set in order to form a shape crystal piece. FIG. 2B is a plan view showing the thickness-shear vibration type crystal piece M1 which is the subject of the invention.

  The AT cut is a fixed angle (35) around the X axis (electrical axis) of the crystal crystal axis with reference to the Y cut cut surface that is cut so that the principal surface is orthogonal to the Y axis (mechanical axis) of the crystal crystal axis. ° 15 ') Cut with a rotated cut surface. As a result, the AT-cut quartz substrate 11 has a main surface that is parallel to the X axis and inclined with respect to the Z axis (optical axis).

  In this embodiment, an AT cut substrate is used as the quartz substrate 11, but the present invention is not necessarily limited to this, and other cut forms may be used. For example, if it is driven in another thickness shear vibration mode such as SC cut (vibration mode in which the front and back main surfaces in the thickness direction of the quartz crystal plate vibrate so as to slide in opposite directions along the surface direction), You may apply to the quartz substrate of another cut form.

  In SC cut, the surface perpendicular to the Y-axis of the crystal is rotated by a fixed angle (about 35 °) around the X-axis, and is further cut by a cut surface rotated by a fixed angle (about 22 °) around the Z-axis. Is.

  In the figure, the blacked out portions are the penetrating regions 4 formed in a penetrating state on the front and back of the quartz substrate 11 by wet etching on the quartz substrate 11. The thickness-shear vibration type crystal piece M1 includes a plurality of (12 × 4 × 3 in the illustrated example) rectangular crystal piece portions 1, a support frame portion 2 common to the plurality of crystal piece portions 1, and a plurality of crystal pieces. Each of the pieces 1 is connected to the support frame 2 and has a plurality of connecting parts 3 for separation which are scheduled to be separated there.

  FIG. 3 shows an enlarged portion of one section 12. On the base end surface E on the X-axis plus side of the crystal piece 1, separation connecting portions 3, 3 are arranged at both ends in the Z ′ direction, and the crystal piece is interposed via these two separation connecting portions 3, 3. The part 1 is integrally connected to the support frame part 2.

  In the figure, a right-angled L-shaped broken line h1 is drawn as a boundary between the crystal piece portion 1 and the separating connecting portions 3 and 3, and a straight line is used as a boundary between the support frame portion 2 and the separating connecting portions 3 and 3. A broken line h2 is drawn, but these broken lines are virtual. In particular, a right-angled L-shaped broken line h1 corresponds to the virtual side surface K1 and the virtual base end surface K2 in FIG.

  There is a penetrating region 4 between the base end face E of the crystal piece 1 and the support frame 2 between the pair of separating connecting portions 3 and 3. Therefore, the crystal piece portion 1 is connected to the support frame portion 2 in a cantilevered state via the pair of separation connecting portions 3 and 3 at the base end surface E on the X-axis plus side. Yes. The X-axis plus side end of the crystal piece 1 is a fixed end, whereas the X-axis minus side end is a free end.

  As illustrated, the virtual corner portion Q1, the virtual side surface K1, and the virtual base end surface K2 are buried in a continuous region between the crystal piece portion 1 and the separation connecting portion 3 and are not actually exposed to the outside. These parts are covered with the connecting part 3 for separation.

  In order to obtain such a form, a mask pattern is formed on the white area shown in FIGS. 2B and 3 when wet etching is performed on the quartz crystal substrate 11, and black areas are filled in the wet etching. It is made to remove in the penetration state. When wet etching is performed, the imaginary side face K1 and the imaginary base end face K2, particularly the imaginary corner Q1, are covered with the separation connecting portion 3 so as not to come into contact with the etching solution. This is to prevent excessive erosion of etching.

  As will be described later, an excitation electrode and an extraction electrode are formed on the main surface of the crystal piece portion 1 in a later step, and then the crystal piece portion 1 on which the electrode has been formed is supported by a support frame portion 2 at the connecting portions 3 and 3 for separation. The crystal diaphragm is obtained by separating from the above.

  When the crystal diaphragm is separated, the crystal piece 1 is planned to be separated from the separation connecting portions 3 and 3 at the virtual side face K1 and the virtual base end face K2. This is to ensure the ease of separation of the crystal piece 1 from the separation connecting portion 3.

  With the synergy between the prevention of excessive etching erosion on the X axis plus side and ensuring the ease of separation of the crystal piece, the shape accuracy of the quartz crystal plate to be obtained by separation is improved and its vibration characteristics are improved. It will improve.

  In addition, this invention can also make the method of producing a thickness-shear vibration type crystal piece a technical object. The manufacturing method includes a crystal piece having a rectangular crystal piece, a support frame portion of the crystal piece portion, and a separation connecting portion that connects the crystal piece portion to the support frame portion and is scheduled to be separated therefrom. Is produced from a quartz substrate.

  In this manufacturing method, as in the above-described crystal piece, the crystal substrate has a crystal face whose principal surface is parallel to the X axis (electrical axis) of the crystal crystal axis and to the Z axis (optical axis). It is used in such a form that it is inclined and is driven in a thickness-shear vibration mode.

  This manufacturing method includes a step of forming an outer shape of a crystal piece having a rectangular crystal piece and a separation connecting portion as constituent elements by photolithography technology and wet etching for the crystal substrate. Then, in the step of forming the outer shape of the crystal piece portion, the mask pattern to be used is the base end portion of the crystal piece portion on the X-axis plus side as the mask pattern portion with respect to the separating connecting portion, and Z on the main surface. Mask pattern portions are formed at corners at both ends in the Z′-axis direction, which is an axis inclined from the axis. Further, as a mask pattern portion for at least one separation connecting portion, a virtual side surface obtained by virtually extending the outer surface of the Z′-axis direction end portion of the crystal piece portion in the X-axis direction and the X-axis plus side of the crystal piece portion The mask pattern portion is formed in a form that continuously covers the virtual base end face obtained by virtually extending the base end face in the Z′-axis direction from the outside.

  According to the method of manufacturing the thickness-shear vibration type crystal piece, the above-described prevention of excessive etching erosion on the plus side of the X axis and securing of the ease of separation of the crystal piece portion can be obtained by separation. Thus, the thickness-shear vibration type crystal piece according to the present invention, which exhibits the usefulness of improving the shape accuracy of the quartz crystal plate and improving the vibration characteristics, is obtained.

  Next, a specific method for manufacturing a crystal oscillator will be described.

  The manufacturing process can be broadly divided into [1] a step of adjusting the thickness of the crystal piece, [2] a step of forming the outer shape of the crystal piece, [3] a step of forming an electrode, and [4] sampling of a crystal diaphragm by separation. Step, [5] Step of assembling the crystal oscillator. In addition, with respect to the above [1] and [2], there is also a method in which the step of forming the outer shape of the crystal piece portion is performed prior to the thickness adjustment step of the crystal piece portion.

  Hereinafter, it demonstrates in order.

[1] Step of adjusting thickness of crystal piece 1 In order to set the natural frequency of crystal piece 1 to a desired frequency, as shown in FIG. Adjust the thickness.

  Specifically, it is as follows. As shown in FIGS. 4A and 4B, a metal film 21 made of Cr (chromium) and Au (gold) is formed on both the front and back surfaces of the cleaned quartz substrate 11 by vacuum deposition or sputtering. In forming the metal film 21, since it is difficult to form the Au layer directly on the quartz substrate 11, the Cr layer is first formed, and then the Au layer is formed on the Cr layer. Next, a resist film 22 is formed on the metal film 21.

  Then, the resist film 22 is patterned using a photolithography technique. Next, the metal film 21 is etched with a potassium iodide (KI) solution using the resist film pattern to form a laminated mask 23 corresponding to each section 12.

  Next, as shown in FIG. 4C, the quartz substrate 11 is immersed in a hydrofluoric acid solution for etching, and the thickness of the region corresponding to the quartz piece portion 1 of each section 12 is reduced. When the frequency is confirmed by a probe (probe: not shown) or the like, the resist film 22 on the surface of the quartz substrate 11 and the metal film 21 and the resist film 22 on the back surface of the quartz substrate 11 are peeled off. Thereby, as shown in FIG. 2A and FIG. 4C, a plurality of sections 12 whose thicknesses have been adjusted are formed in the quartz substrate 11.

[2] Step of forming the outer shape of the crystal piece Next, the process proceeds to the step of forming the outer shape of the crystal piece. As shown in FIG. 5A, a metal film 24 made of Cr (chromium) and Au (gold) is formed on both the front and back surfaces of the quartz substrate 11 after thickness adjustment by vacuum deposition or sputtering. Next, a resist film 25 is formed on the metal film 24 (Au layer).

  Next, as shown in FIG. 5B, the resist film 25 is patterned by a photolithography technique (exposure / development / post-bake). The mask pattern at this time has a shape corresponding to the white area shown in FIGS. 2B and 3 as described above. Then, using the mask pattern, the metal film 24 is etched with a potassium iodide solution (metal etching) to form an outer shape mask pattern 26 for forming the outer shape of the crystal piece 1 on both the front and back surfaces of the crystal substrate 11.

  The outer shape mask pattern 26 has a shape corresponding to the white area shown in FIGS. That is, each of the pair of left and right separation connecting portions 3 and 3 corresponds to the crystal piece portion while covering the virtual side face K1 in the crystal piece portion 1 equivalent region and the virtual base end face K2 connected at right angles thereto. The shape corresponding to the region corresponding to 1 and the region corresponding to the support frame portion 2 are integrally formed.

  After the formation of the outer mask pattern 26, as shown in FIG. 5C, the crystal substrate 11 is etched along the outer mask pattern 26 (crystal etching), so that the groove 27 on the upper surface side of the crystal substrate 11 and the lower surface side of the crystal substrate 11 are etched. Groove portions 28 are formed. As the etching progresses, the bottom surfaces of the upper and lower groove portions 27 and 28 become thinner, the bottom surfaces disappear and penetrate vertically, and a through region 4 is formed as shown in FIG. As a result, the outer shape of the crystal piece 1 is formed.

  Next, the resist film 25 and the metal film 24 remaining on the front and back surfaces of the quartz substrate 11 are peeled off, and the quartz piece 1 is cleaned. As a result, as shown in FIGS. 5E and 3, in each section 12, the base end portion on the X-axis plus side of the crystal piece portion 1 is paired at each corner portion at both ends in the Z′-axis direction. A state in which the separating connecting portions 3 and 3 are integrally connected to the support frame portion 2 appears. The pair of separation connecting portions 3 and 3 are respectively a virtual side surface K1 obtained by virtually extending the outer surface A of the end portion in the Z′-axis direction of the crystal piece 1 in the X-axis direction and the X-axis plus side of the crystal piece 1. The virtual base end face K2 obtained by virtually extending the base end face E in the Z′-axis direction is continuously covered from the outside.

  The outer shape forming process of the crystal piece portion 1 is performed in the form as described above, and the thickness-shear vibration type crystal piece M1 is obtained. The thickness-shear vibration type crystal piece M1 has the advantages described in the above section [Effects of the invention].

[3] Electrode Formation Step Next, the process proceeds to the excitation electrode and extraction electrode formation step. This will be described with reference to FIG. After the outer shape of the crystal piece 1 is formed, a metal film 29 and a resist film 30 are formed on both the front and back surfaces of the crystal piece 1 in the same manner as described above, as shown in FIG. Next, as shown in FIGS. 6B and 6C, mask patterns corresponding to the shapes of the excitation electrodes 31 and 31 and the extraction electrodes 32 and 32 are formed by photolithography and etching using a potassium iodide solution as described above. Formed on both the front and back surfaces of the crystal piece 1

  Then, as shown in FIG. 6C, the metal film 29 is etched to form the excitation electrodes 31 and 31 on the X axis minus side, and the extraction electrodes 32 and 32 are formed on the X axis plus side. Next, as shown in FIG. 6D, the front and back resist films 30 are removed to form a rectangular crystal piece 40.

  Thereby, as shown in FIG. 7, in each of the sections 12 on the crystal substrate 11, a plurality of rectangular crystal piece portions 40 in which the excitation electrodes 31 and 31 and the extraction electrodes 32 and 32 are formed on the front and back are respectively paired. A thickness-shear vibration type crystal piece M2 with electrodes in a form integrally connected to the support frame portion 2 via the connecting portions 3 and 3 for separation is produced. This thickness-shear vibration type crystal piece M2 with electrodes has the advantages described in the above section [Effects of the invention].

[4] Step of Extracting Rectangular Crystal Piece by Separation Next, as shown in FIG. 6 (e), the rectangular crystal piece 40 is separated at the connecting portions 3 and 3 for separation by laser dicing, for example. The diaphragm 41 is separated into individual pieces. Even the separated crystal diaphragm 41 has the advantages described in the above section [Effects of the invention]. In addition, there is also a general folding method for dividing the crystal diaphragm 41 into individual pieces.

[5] Step of Assembling Crystal Oscillator Next, although not shown in the drawings, the crystal vibrating plate 41 obtained by separating from the thickness-shear vibration type crystal piece M2 with electrodes is accommodated in a ceramic package, and the crystal An extraction circuit 32 in the vibration plate 41 and a pad electrode in the package are mechanically and electrically bonded via a conductive bonding material, and an integrated circuit including an oscillation circuit for exciting and driving the crystal vibration plate 41 is accommodated in the package.

  Finally, the package is covered with a ceramic or metal lid (lid) to hermetically seal. In this crystal oscillator, the crystal diaphragm 41 has excellent shape accuracy and exhibits high quality vibration characteristics.

(Example 2)
Next, a description will be given of a second embodiment in which the crystal part separation ease is enhanced in comparison with the first embodiment.

  As shown in FIG. 8 and FIG. 9, the imaginary side surface K <b> 1 and a right angle to the imaginary side surface K <b> 1 are formed as the separation support portion 50 for facilitating separation in the integral connection region of the crystal piece 1 and the separation connection portion 3. An L-shaped concave groove 51 is formed on the main surface in a state adjacent to the continuous virtual base end face K2. The L-shaped concave groove 51 has an action of reducing a resistance (resistance) to an applied force when the crystal piece 1 or the rectangular crystal piece 40 is separated.

  An experiment was conducted on the size of the L-shaped concave groove 51. In the experiment using a 40 μm thick quartz wafer (quartz substrate), the groove width and the groove depth were varied, and the support performance and stability of the crystal piece 1 by the connecting part 3 for separation. Then, confirmation was made of the ease of breakage of the crystal piece 1 by moving the folding pin downward, the presence or absence of excessive etching erosion, and the like. The change range of the groove width was 5 to 50 μm, and the change range of the groove depth was 4 to 61 μm.

  When the groove width was 5 μm and the groove depth was 4 μm, there was a tendency that it was difficult to break. Further, when the groove width was 25 μm and the groove depth was 27 μm, the crystal piece part shook a little and there was a tendency that it was difficult to handle. The experimental results are summarized in Table 1.

  By keeping the above conditions, it is possible to realize an etching stop in the groove of the L-shaped concave groove 51 during wet etching and prevent excessive erosion.

  From the results of the experiment and various considerations based on the results, it was confirmed that the groove width of 6-22 μm is appropriate and the groove depth of 4-23 μm is appropriate. The groove width is preferably 8 to 18 μm, and the groove depth is preferably 6 to 20 μm. More preferably, the groove width is 10 to 15 μm and the groove depth is 8 to 14 μm.

  The above dimension example is for a quartz wafer having a thickness of 40 μm, but it was also confirmed that a quartz wafer having a thickness of 40 μm may have an allowable range up to a groove width of about 25 μm and a groove depth of about 27 μm.

  Thus, if the groove width and groove depth of the L-shaped concave groove 51 are optimized, handling workability is improved.

  Note that the L-shaped concave groove 51 may be formed only on the front surface side of the separation connecting portion 3, or may be formed only on the back surface side, or may be formed on both the front and back surfaces.

(Other examples)
The separation support unit 50 will be described in forms other than the L-shaped groove 51. In FIG. 10A, a plurality of recesses 52 are formed at intervals in the connection region along the virtual side surface K1 and the virtual base end surface K2 continuous at right angles to the virtual side surface K1, and separated by the plurality of recesses 52. The support unit 50 is used. In this case, the opening intervals may be equal intervals or unequal intervals.

  Further, when a plurality of recesses are formed along the virtual side surface K1 and the virtual base end surface K2, a rough region with a reduced number of formations per unit area is formed in the vicinity of the corner, and per unit area as the distance from the corner is increased. There is also an aspect in which a dense region is formed with a large number of formations.

  Such a group of recesses 52 may be formed only on the front surface side of the separation connecting portion 3, or may be formed only on the back surface side, or may be formed on both the front and back surfaces. When forming on both front and back surfaces, they may be arranged at the same position on the front and back in plan view, or the positions may be shifted on the front and back.

  Or it may replace with a recess and may comprise a separation assistance part with a plurality of penetration holes formed at intervals (illustration omitted). Alternatively, instead of replacing all of the recesses with through holes, only a part of the recesses may be replaced with through holes.

  In FIG. 10B, the size (diameter) of the plurality of recesses 52 is changed. In the virtual corner portion Q1 of the crystal piece 1 that changes the direction from the X-axis direction to the Z′-axis direction in the connection region, the size of the recess 52 is minimized, and the size is sequentially increased as the distance from the virtual corner portion Q1 increases. It is.

  FIG. 10 (c) shows a modification of the L-shaped concave groove 51, in which the width of the concave groove 53 is minimized in the immediate vicinity of the virtual corner portion Q1, and the width is sequentially increased as the distance from the virtual corner portion Q1 increases. It is.

  In the case of FIGS. 10B and 10C, the intensity distribution of the separation support unit 50 has the highest intensity at the virtual corner Q1, and the intensity gradually decreases as the distance from the virtual corner Q1 increases. As a result, the separation of the crystal piece 1 at the separation connecting portion 3 becomes easier, and the shape accuracy of the crystal diaphragm is further increased. In addition, when the crystal piece is handled, it is possible to reliably prevent the crystal piece portion 1 from being accidentally dropped due to vibration or impact.

  FIG. 11 and FIG. 12 (a) show another embodiment of a thickness-shear vibration type crystal piece with electrodes. In the embodiment described so far, the extraction electrodes 32 and 32 are arranged at the edge on the X axis plus side of the crystal piece 1 (see, for example, FIG. 7). In the embodiment shown in a), the extraction electrodes 32 and 32 are arranged on the outer surface edge of the Z′-axis direction end of the crystal piece 1. More specifically, the excitation electrodes 31 and 31 are formed in the central portion of the front and back surfaces of the crystal piece 1 so as to face each other. The extraction electrodes 32 and 32 are formed on the side edge portions in a state of being electrically connected to the excitation electrodes 31 and 31.

  In the embodiment of FIG. 12B, the crystal piece 1 is formed in a horizontally long shape. That is, the side along the X-axis direction of the crystal piece 1 is a short side, and the side along the Z′-axis direction is a long side. Excitation electrodes 31 and 31 and extraction electrodes 32 and 32 are formed on such a horizontally long crystal piece 1 as in FIG.

  In FIG. 11 and FIG. 12, since the other configuration is the same as that of the above embodiment, the same reference numerals are given to the same portions, and the description is omitted.

  Note that the present invention may be applied to a mesa-type quartz diaphragm 60 as shown in FIG. Unlike a parallel plate, the mesa type has a thick central portion and a thin outer portion or periphery, and vibration energy can be confined in the central portion. By confining vibration energy in this way, CI (crystal impedance) can be improved and stabilized.

  In the mesa-type quartz diaphragm 60, the crystal piece 1 has a central thick part 1A and a peripheral thin part 1B. The vertical position of the peripheral thin part 1B is as shown in the figure. In addition to the form located in the center in the thickness direction of the central thick part 1A, it may be flush with the surface of the central thick part 1A, or may be flush with the back surface of the central thick part 1A.

  Furthermore, the present invention may be applied to an inverted mesa type crystal diaphragm having a thin central portion and thick outer portions. The inverted mesa type is advantageous for higher frequency.

  Further, as shown in FIG. 14, for the L-shaped separating connecting portions 3 and 3 that cover the virtual side face K1 and the virtual base end face K2 that extends perpendicularly to the virtual side face K1, the dimension in the X-axis direction is set to the Z ′ axis. It may be longer than the dimension in the direction.

  3 and 9, another separation connecting portion 3 ′ for supporting the crystal piece 1 with respect to the support frame portion 2 is connected to the end of the crystal piece 1 on the minus side of the X axis. It may be formed integrally with the support frame 2 in the part. Although not shown, the same applies to FIG.

  As another aspect of the separation connecting portion 3 ′, it is not necessary to have a form that covers the corner of the crystal piece 1 from two directions like the separation connecting portion 3 of the above embodiment.

  This separate connecting portion 3 'is for stably supporting the crystal piece 1 on the support frame 2, and does not have to prevent excessive etching erosion. However, it is not prevented that the crystal piece portion 1 is configured to be covered in two directions with respect to one end or both end corners in the left-right direction at the end on the X axis minus side. In that case, another separation connecting portion 3 ′ is arranged at the position of the virtual line W 2.

  As described above, according to the thickness-shear vibration type crystal piece of the present embodiment, it is possible to achieve both prevention of excessive etching erosion on the X-axis plus side and ensuring the ease of separation of the crystal piece part and separation. Therefore, the shape accuracy of the quartz crystal plate can be improved, and the vibration characteristics can be improved.

  The technology of the present invention can be obtained by separating the quartz piece that is in the thickness-shear vibration mode by preventing both excessive etching erosion on the X-axis plus side and ensuring the ease of separation of the quartz piece. This is useful as a technique for improving the shape characteristics of a quartz diaphragm and improving its vibration characteristics.

DESCRIPTION OF SYMBOLS 1 Crystal piece part 2 Support frame part 3 Separation connection part 4 Through region 11 Crystal substrate 31 Excitation electrode 32 Extraction electrode 40 Rectangular crystal piece part 41 Crystal diaphragm 50 Separation support part K1 Virtual side face K2 Virtual base end face Q1 Virtual corner part M1 Thickness-slip vibration type crystal piece M2 Thickness-slip vibration type crystal piece with electrode

Claims (12)

A rectangular crystal piece portion; a support frame portion that supports the crystal piece portion; and a separation connecting portion that connects the crystal piece portion to the support frame portion , wherein the crystal piece portion is the support frame portion. In the thickness-shear vibration crystal piece that is connected to the separation connecting portion and the crystal piece portion can be separated from the support frame portion at the separation connecting portion,
The separation connecting portion is a base end portion of the crystal piece portion on the X axis (electrical axis) plus side of the crystal crystal axis and is an axis inclined from the Z axis (optical axis) of the crystal crystal axis. A virtual side surface disposed at at least one corner in the axial direction and virtually extending in the X-axis direction on the outer surface of the Z′-axis direction end portion of the crystal piece by the connecting portion for separation, and the crystal A virtual base end surface virtually extending the base end surface on the X axis plus side of one part in the Z′-axis direction is continuously covered from the outside,
The thickness-shear vibration type crystal piece, wherein the separation connecting portion is provided with a separation support portion that facilitates the separation in a region along the virtual side surface and the virtual base end surface.   2. The thickness according to claim 1, wherein the crystal piece is configured in an AT-cut type whose main surface is parallel to the X axis (electric axis) of the crystal crystal axis and inclined with respect to the Z axis (optical axis). Sliding vibration type crystal piece.   3. The thickness-shear vibration crystal piece according to claim 1, wherein the separation connecting portions are respectively disposed at both end portions in the Z′-axis direction of the crystal piece portion.   The separation connecting portion is configured such that the connection length at the virtually extended virtual side surface is shorter than the connection length at the virtually extended virtual base end surface with respect to the connection length with the crystal piece portion. The thickness shear vibration type crystal piece according to any one of claims 1 to 3, wherein the thickness shear vibration type crystal piece is provided.   In the connecting portion for separation, the length of the connection with the crystal piece portion is the same as the connection length at the virtually extended virtual base end surface or the connection length at the virtually extended virtual side surface. The thickness-shear vibration type crystal piece according to any one of claims 1 to 3, wherein the thickness-shear vibration type crystal piece is configured to be longer.   The thickness-shear vibration type crystal according to any one of claims 1 to 5, wherein the separation connecting portion is configured to be thinner than the crystal piece portion and the support frame portion. Piece. The thickness-shear vibration type crystal piece according to any one of claims 1 to 6, wherein the separation support unit is configured by a groove, a plurality of recesses, or a plurality of through holes.   The thickness-shear vibration type crystal piece according to any one of claims 1 to 7, wherein an excitation electrode formed to face central portions of both front and back surfaces of the crystal piece part, and the front and back excitation electrodes A thickness-shear vibration type crystal piece with an electrode, comprising an extraction electrode formed on the X-axis plus side edge on both the front and back surfaces of the crystal piece in a state where it is electrically connected to the crystal.   The thickness-shear vibration type crystal piece according to any one of claims 1 to 7, wherein an excitation electrode formed to face central portions of both front and back surfaces of the crystal piece part, and the front and back excitation electrodes A thickness-shear vibration type crystal piece with an electrode, comprising an extraction electrode formed on the outer surface edge of the Z′-axis direction end portion on both the front and back surfaces of the crystal piece portion in a state of being electrically connected to the electrode. A rectangular crystal piece portion provided with a pair of excitation electrodes and these extraction electrodes facing both front and back surfaces, and a support frame portion that supports the crystal piece portion, and the crystal piece portion is separated. In a method of manufacturing a crystal diaphragm from a thickness-slip vibration type crystal piece connected to the support frame part via a connection part for
The crystal piece is tilted from the Z-axis (optical axis) of the crystal crystal axis by etching from the crystal substrate at the base end portion of the crystal piece portion on the X axis (electrical axis) plus side of the crystal crystal axis. At each corner of both ends in the Z′-axis direction, which is the axis, a virtual side surface in which the outer surface of the Z′-axis direction end portion of the crystal piece portion is virtually extended in the X-axis direction and the X-axis plus of the crystal piece portion Forming a virtual base end surface virtually extending in the Z′-axis direction on the side base end surface into an outer shape continuously covered by the separation connecting portion;
Forming the excitation electrode and the extraction electrode on both front and back surfaces of the crystal piece,
Separating the crystal piece from the support frame at the separation connecting portion;
A method of manufacturing a quartz crystal diaphragm, comprising: A step of accommodating the quartz crystal plate obtained by the manufacturing method according to claim 10 in a package;
Mechanically and electrically bonding the lead electrode in the quartz crystal diaphragm and the pad electrode in the package with a conductive bonding material;
Hermetically sealing the package;
A method of manufacturing a crystal resonator , comprising : A crystal oscillator comprising a step of housing a crystal diaphragm obtained by the manufacturing method according to claim 10 and an integrated circuit including an oscillation circuit for exciting and driving the crystal diaphragm in a package. Manufacturing method .