JP6295607B2 - Manufacturing method of vibration element - Google Patents

Description

  The present invention relates to a method for manufacturing a vibration element, a vibration element, and an electronic apparatus.

The vibration element is used for, for example, vehicle body control in a vehicle, detection of a vehicle position of a car navigation system, vibration control correction (so-called camera shake correction) of a digital camera, a video camera, etc., and detects physical quantities such as angular velocity and acceleration. Sensors are known. For example, Patent Document 1 describes an angular velocity sensor (vibration gyro sensor).
The vibration gyro sensor described in Patent Literature 1 includes a base, a connecting arm extending from the base, a drive arm extending from the tip of the connecting arm, and a detection arm extending from the base. When such a vibration gyro sensor receives an angular velocity in a predetermined direction in a state where the drive arm is bent and vibrated, a Coriolis force acts on the drive arm, and accordingly, the detection arm is bent and vibrated. By detecting such bending vibration of the detection arm, the angular velocity can be detected.

The base and drive arm of such a vibration gyro sensor are formed of, for example, a piezoelectric material. And a base part and a drive arm are formed by processing a piezoelectric material using a photolithographic technique and an etching technique.
For example, in Patent Document 2, a buffer layer, a lower electrode layer, a piezoelectric layer, an upper electrode layer, and a resist film are sequentially stacked on the surface of a substrate, and then the outer periphery of the resist film is partway through the piezoelectric layer by dry etching. A method of manufacturing a piezoelectric functional component having an etching step is disclosed. Then, the piezoelectric layer etched halfway is subjected to etching again in a subsequent process, and the remaining portion is removed. According to this method, when the piezoelectric layer is etched, an effect that the piezoelectric layer is less likely to be peeled can be obtained as compared with the case where the etching is performed until the lower electrode layer is reached at once.
On the other hand, in the manufacturing method of Patent Document 2, although the step of exposing the lower electrode layer is not particularly described, the auxiliary electrode described in Paragraph 0010 of Patent Document 2 is exposed from a window provided in the piezoelectric layer. It is disclosed. For this reason, in addition to the manufacturing method described in Patent Document 2, a step of exposing the lower electrode layer is also required.

Hereinafter, a method in which a step of exposing the lower electrode layer is added to the manufacturing method of Patent Document 2 will be described as a conventional technique.
10 to 12 are cross-sectional views for explaining a conventional method for manufacturing a vibration element. 13 is a perspective view of the vibration element manufactured by the manufacturing method shown in FIGS. 10 to 12, and FIG. 14 is a cross-sectional view taken along line AA of the vibration element shown in FIG. 10 to 12 are also cross-sectional views corresponding to the line AA in FIG.

The vibration element 9 shown in FIGS. 13 and 14 is a tuning fork type element, and includes a base 901 and two vibrating arms 902 extending from the base 901 in the same direction. The base 901 and the vibrating arm 902 are integrally formed of a laminated body in which a plurality of layers are laminated. This laminated body was provided on a silicon substrate 91, a buffer layer 92 provided thereon, a lower electrode layer 93 provided thereon, a piezoelectric layer 94 provided thereon. An upper electrode layer 95. The lower electrode layer 93 is exposed on the upper surface of the vibration element 9 through an auxiliary electrode 96 provided in a window portion 941 that penetrates the piezoelectric layer 94. The vibration element 9 can be excited by applying a voltage between the upper electrode layer 95 and the auxiliary electrode 96 (lower electrode layer 93).
The upper electrode layer 95 provided on each vibrating arm 902 constitutes two upper electrode layers 951 and 952 arranged in parallel, and the upper electrode layer 951 and the upper electrode layer 952 are electrically separated from each other. ing.
For convenience of explanation, the auxiliary electrode 96 is omitted in FIG.

Next, a method for manufacturing the vibration element 9 (a conventional method for manufacturing a vibration element) will be described in the order of steps.
In the conventional method of manufacturing the vibration element 9 shown in FIGS. 10 to 12, first, as shown in FIG. 10A, from below, the silicon substrate 91, the buffer layer 92, the lower electrode layer 93, the piezoelectric layer 94, and the upper electrode are formed. Layers 95 are stacked in this order.

Next, a resist film is formed on the upper electrode layer 95 and patterned into a necessary shape, thereby forming a first resist film 971 as shown in FIG.
Next, it is subjected to the first dry etching, and the piezoelectric layer 94 is partially removed as shown in FIG.

Next, after removing the first resist film 971, as shown in FIG. 11D, among the island-shaped portions composed of the upper electrode layer 95 and the piezoelectric layer 94 covered with the first resist film 971, A second resist film 972 is formed so as to cover a region around the island-shaped portion of the upper surface, the side surface, and the upper surface of the piezoelectric layer 94.
Next, it is subjected to the second dry etching, and as shown in FIG. 11E, the piezoelectric layer 94, the lower electrode layer 93, and the buffer layer 92 left without being removed are removed.
Next, the type of etching gas for dry etching is changed, and the silicon substrate 91 is subjected to the third etching. Thus, as shown in FIG. 11F, the silicon substrate 91 is processed so as to penetrate therethrough.

Next, although not described in Patent Document 2, since it is necessary to expose the lower electrode layer 93, after removing the second resist film 972, as shown in FIG. A film 973 is formed. At this time, the third resist film 973 is not formed in the region where the lower electrode layer 93 is exposed.
Next, it is subjected to the fourth dry etching, and as shown in FIG. 12H, the lower electrode layer 93 is exposed in the region where the third resist film 973 is not formed.
Thereafter, the third resist film 973 is removed to obtain the vibration element 9 shown in FIG.

JP 2006-105614 A JP 2008-300855 A

However, the conventional method for manufacturing a vibration element requires at least four etching steps. For this reason, it was difficult to increase the manufacturing yield, and it was necessary to reduce the number of steps as much as possible. In addition, it is necessary to change the type of etching gas during the manufacturing process, which requires a lot of labor and time.
An object of the present invention is to provide a vibration element manufacturing method capable of manufacturing a vibration element with fewer steps, a highly reliable vibration element, and a highly reliable electronic device including the vibration element.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples.
[Application Example 1]
The method for manufacturing a vibrating element according to the present invention includes a base, two vibrating arms provided so as to extend from the base, and a first electrode and a second electrode provided on each of the bases. A method of manufacturing a vibrating element configured to excite each vibrating arm by applying a voltage between an electrode and the second electrode,
Preparing a laminate in which a substrate, a first electrode layer, a piezoelectric layer, and a second electrode layer are laminated in this order;
A step of overlaying a first mask on a region of the laminate to form the vibrating arm and a region of the first electrode;
Processing the half-thickness of the piezoelectric layer by applying a first etching process to the stacked body through the first mask;
After removing the first mask, overlaying a second mask on a region for forming the vibrating portion;
Forming the first electrode by performing a second etching process on the stacked body through the second mask to process the first electrode layer in a region where the first electrode is formed;
After removing the second mask, overlaying the third mask so that a region located between the two vibrating arms is exposed;
A step of performing a third etching process on the stacked body through the third mask to process until a region located between the two vibrating arms penetrates;
Removing the third mask to expose the second electrode layer and forming the second electrode;
It is characterized by having.
Accordingly, since the processing for exposing the first electrode layer is performed while processing the piezoelectric layer, the vibration element can be manufactured with fewer steps.

[Application Example 2]
In the method for manufacturing a resonator element according to the aspect of the invention, it is preferable that the third mask is provided so as to overlap a portion extending from a region where the vibrating arm is formed to a region outside the region where the vibrating arm is formed.
Thereby, it is possible to prevent the piezoelectric layer and the lower electrode layer in the region forming the vibrating arm from being processed from the side surface in the third etching process. As a result, it is possible to prevent the vibration characteristics of the vibrating arm from being damaged.

[Application Example 3]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable that the second etching process is performed on the stacked body so that the laminated body is processed to the middle of the thickness of the substrate in a region located between the two vibration arms.
As a result, while processing until the first electrode layer is exposed, the piezoelectric layer, the lower electrode layer, and the substrate can also be processed at the same time in the region, so that compared with the case where these steps are performed separately. Processing efficiency can be increased.

[Application Example 4]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable that the stacked body further includes an intermediate layer that is provided between the substrate and the first electrode layer and includes a metal oxide.
Thereby, the adhesiveness of a board | substrate and a 1st electrode layer can be improved more, and the reliability of a vibration element can be improved.

[Application Example 5]
In the method for manufacturing a resonator element according to the aspect of the invention, it is preferable that the first electrode layer is made of platinum or an alloy containing platinum.
Since these materials have a relatively low processing rate of the etching process, workability is improved when the first electrode layer is exposed by the etching process.

[Application Example 6]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable that the second electrode layer is made of gold or an alloy containing gold.
Since these materials have relatively high weather resistance, it is possible to suppress the occurrence of problems such as a decrease in conductivity over time.

[Application Example 7]
In the method for manufacturing a vibration element according to the aspect of the invention, it is preferable that the substrate is made of silicon.
Since a silicon substrate can be precisely processed by a photolithography technique, an etching technique, or the like, it is preferably used for manufacturing a vibration element.

[Application Example 8]
In the method for manufacturing a resonator element according to the aspect of the invention, it is preferable that the first etching process, the second etching process, and the third etching process are dry etching processes using the same type of etching gas.
Thereby, since gas exchange etc. become unnecessary, a man-hour can be reduced.

[Application Example 9]
The vibration element of the present invention is provided with a base including a laminate in which a substrate and a first electrode layer are stacked, and a portion extending from the base, and a part of the substrate, the first electrode layer, and the piezoelectric layer are provided. Two vibrating arms including a laminate in which the second electrode layer is laminated in this order,
The substrate has a first surface located on the side where the first electrode layer is laminated, and a second surface located outside the first surface through a step. It is characterized by that.
This makes it difficult for stress to concentrate on the outer edge portion of the connection surface between the substrate and the first electrode layer, so that peeling between the substrate and the first electrode layer is difficult to occur. As a result, a highly reliable vibration element can be obtained.
[Application Example 10]
An electronic apparatus according to the present invention includes the vibration element according to the present invention.
As a result, a highly reliable electronic device can be obtained.

It is a top view which shows embodiment of the vibration element of this invention. It is the BB sectional view taken on the line shown in FIG. FIG. 3 is a partially enlarged view in the vicinity of a vibrating arm shown in FIG. 2. It is sectional drawing for demonstrating embodiment of the manufacturing method of the vibration element of this invention. It is sectional drawing for demonstrating embodiment of the manufacturing method of the vibration element of this invention. It is sectional drawing for demonstrating embodiment of the manufacturing method of the vibration element of this invention. 1 is a perspective view illustrating a configuration of a mobile (or notebook) personal computer including a vibration element of the present invention. It is a perspective view which shows the structure of a mobile telephone (PHS is also included) provided with the vibration element of this invention. It is a perspective view which shows the structure of a digital still camera provided with the vibration element of this invention. It is sectional drawing for demonstrating the manufacturing method of the conventional vibration element. It is sectional drawing for demonstrating the manufacturing method of the conventional vibration element. It is sectional drawing for demonstrating the manufacturing method of the conventional vibration element. It is a perspective view of the vibration element manufactured by the manufacturing method shown in FIGS. It is AA sectional view taken on the line of the vibration element shown in FIG.

Hereinafter, a method for manufacturing a vibration element, a vibration element, and an electronic apparatus will be described in detail based on preferred embodiments shown in the accompanying drawings.
<Vibration element>
First, an embodiment of the vibration element of the present invention will be described.
FIG. 1 is a plan view showing an embodiment of the vibration element of the present invention, and FIG. 2 is a cross-sectional view taken along the line BB shown in FIG.

A vibration element 1 shown in FIG. 1 is a tuning fork type element, and includes a base portion 21 and a pair of vibration arms 221 and 222. In order to avoid complication of the drawing, illustration of other parts (electrodes, etc.) other than these is omitted in FIG.
In the following description, the vibration element 1 and the manufacturing method thereof will be described using a tuning fork type element as an example, but the present invention is not limited to such an element. For example, the present invention can be applied to various types of elements such as an H type tuning fork, a tripod tuning fork, a double T type, a comb type, an orthogonal type, and a prism type.

  Such a vibration element 1 is sealed in a package and is electrically connected to a control IC (not shown), whereby a gyro sensor or the like can be constructed. The gyro sensor detects physical quantities such as angular velocity and acceleration, for example, camera shake correction of an imaging device, attitude detection and attitude control of a vehicle or the like in a mobile navigation system using a GPS (Global Positioning System) satellite signal. Used for etc.

In the resonator element 1 shown in FIG. 1, a base portion 21 and a pair of vibrating arms 221 and 222 are integrally formed of a multilayer structure having a plurality of layers.
This laminated body includes a substrate 11, a buffer layer (intermediate layer) 12, a lower electrode layer (first electrode layer) 13, a piezoelectric layer 14 and an upper electrode layer (second electrode layer) 15 from below in FIG. They are laminated in order. By processing this laminated body into a tuning fork type, the vibration element 1 shown in FIG. 1 is obtained.
The size and thickness of the vibration element 1 are appropriately set according to the oscillation frequency (resonance frequency), the outer size, the workability, and the like of the vibration element 1.

Hereinafter, each part of the vibration element 1 will be described in more detail.
The base 21 is a part that supports one end of the pair of vibrating arms 221 and 222, and four electrodes 23, 24, 25, and 26 serving as contact points of electrode layers provided on the pair of vibrating arms 221 and 222 are provided. Is provided. By connecting the electrode and the IC with a wiring (not shown), the vibration element 1 can be excited, and the detected signal can be received and analyzed by the IC.

Of the four electrodes 23, 24, 25, 26, the electrode (first electrode) 23 has a structure in which the lower electrode layer 13 provided on the base 21 is partially exposed. On the other hand, the structure of the remaining electrodes 24, 25, 26 is a structure in which the upper electrode layer 15 provided on the base 21 is exposed. Of these, the electrode 24 corresponds to a second electrode.
Moreover, the part in which the buffer layer 12 is laminated | stacked among the board | substrates 11 provided in the base 21 is in the state protruded locally. In other words, the portion of the substrate 11 provided on the base 21 where the buffer layer 12 is not laminated is thinner than the portion where the buffer layer 12 is laminated. As a result, a step 16 is formed on the substrate 11 between a portion where the buffer layer 12 is laminated and a portion where the buffer layer 12 is not laminated.

The pair of vibrating arms 221 and 222 are long members that extend upward from the base portion 21 in FIG.
Further, as shown in FIG. 2, the vibrating arm 221 is configured by a laminate in which the substrate 11, the buffer layer 12, the lower electrode layer 13, the piezoelectric layer 14, and the upper electrode layer 15 are laminated in this order from below. Yes. Further, the upper electrode layers 15 are separated from each other in the width direction (left-right direction in FIG. 2) orthogonal to the longitudinal direction of the vibrating arm 221. As a result, the upper electrode layer 15 of the vibrating arm 221 functions as a pair of electrically separated electrodes. Here, among the upper electrode layers 15 of the vibrating arm 221 shown in FIG. 2, the left upper electrode layer 15 is the detection electrode 151, and the right upper electrode layer 15 is the excitation electrode 152. Among these, the detection electrode 151 is connected to the electrode 26 provided on the base 21 described above, and the excitation electrode 152 is connected to the electrode 24 provided on the base 21.

  Further, the piezoelectric layer 14 provided on the vibrating arm 221 also has a locally raised portion where the upper electrode layer 15 is laminated. In other words, the portion of the piezoelectric layer 14 provided on the vibrating arm 221 where the upper electrode layer 15 is not laminated is thinner than the portion where the upper electrode layer 15 is laminated. ing. As a result, the piezoelectric layer 14 has a step 17 between a portion where the upper electrode layer 15 is laminated and a portion where the upper electrode layer 15 is not laminated.

In addition, the substrate 11 provided on the vibrating arm 221 also has a locally raised portion where the buffer layer 12 is laminated. In other words, the portion of the substrate 11 provided on the base 21 where the buffer layer 12 is not laminated is thinner than the portion where the buffer layer 12 is laminated. As a result, a step 16 is formed on the substrate 11 between a portion where the buffer layer 12 is laminated and a portion where the buffer layer 12 is not laminated.
Although not shown, a step 17 is generated in the piezoelectric layer 14 in the portion other than the electrode 23 in the base 21 as in the vibrating arm 221.

On the other hand, the vibrating arm 222 has the same structure as the vibrating arm 221.
That is, the upper electrode layers 15 of the vibrating arm 222 are separated from each other in the width direction (left-right direction in FIG. 2) orthogonal to the longitudinal direction of the vibrating arm 222. As a result, the upper electrode layer 15 of the vibrating arm 222 functions as a pair of electrically separated electrodes. Here, among the upper electrode layers 15 of the vibrating arm 222 shown in FIG. 2, the left upper electrode layer 15 is the excitation electrode 153 and the right upper electrode layer 15 is the detection electrode 154. Among these, the excitation electrode 153 is connected to the electrode 24 provided on the base 21, and the detection electrode 154 is connected to the electrode 25 provided on the base 21.

In such a vibration element 1, when a voltage is applied between the excitation electrode 152 (electrode 24) and the lower electrode layer 13 (electrode 23), the piezoelectric layer sandwiched between the excitation electrode 152 and the lower electrode layer 13 The portion 14 expands and contracts to generate vibrations reciprocating in the left-right direction in FIG. Similarly, when a voltage is applied between the excitation electrode 153 and the lower electrode layer 13, the portion of the piezoelectric layer 14 sandwiched between the excitation electrode 153 and the lower electrode layer 13 expands and contracts, and the vibrating arm 222 has the configuration shown in FIG. The vibration which reciprocates in the left-right direction is generated.
When an angular velocity is applied to the vibration element 1 in this state, a force in a direction perpendicular to the vibration direction is generated in the vibrating arms 221 and 222 by Coriolis force. By detecting the amount of deflection due to this force with the detection electrodes 151 and 154, the amount of angular velocity applied to the vibration element 1 can be known.

  Here, in the vibration element 1, as shown in FIG. 2, a step 16 is formed on the substrate 11. As described above, the step 16 is formed by the thickness of the substrate 11 being different between the portion where the buffer layer 12 is laminated and the portion where the buffer layer 12 is not laminated. By providing such a step 16, peeling is less likely to occur between the substrate 11 and the buffer layer 12. This is because, by providing the step 16, for example, a stress caused by a difference in thermal expansion generated between the substrate 11 and the buffer layer 12 or a stress generated by expansion / contraction of the piezoelectric layer 14 causes the connection between the substrate 11 and the buffer layer 12. This is thought to be because it becomes difficult to concentrate on the outer edge of the surface.

  Similarly, a step 17 is formed in the piezoelectric layer 14. As described above, the step 17 is formed by the thickness of the piezoelectric layer 14 being different between a portion where the upper electrode layer 15 is laminated and a portion where the upper electrode layer 15 is not laminated. Providing such a step 17 makes it difficult for separation to occur between the piezoelectric layer 14 and the upper electrode layer 15. This is because, by providing the step 17, for example, a stress caused by a difference in thermal expansion generated between the piezoelectric layer 14 and the upper electrode layer 15 or a stress generated by expansion and contraction of the piezoelectric layer 14 is caused by This is considered to be because it is difficult to concentrate on the outer edge portion of the connection surface with the electrode layer 15.

FIG. 3 is a partially enlarged view of the vicinity of the vibrating arm 221 shown in FIG.
Of the substrate 11 of the vibrating arm 221 shown in FIG. 3, the surface in contact with the buffer layer 12 (the surface located on the lower electrode layer 13 side) is defined as the first surface 111, and the step 16 is provided outside the first surface. The surface that is located between the buffer layer 12 and the buffer layer 12 is not in contact with the second surface 112. The height of the step 16 between the first surface 111 and the second surface 112 is not particularly limited, but when the thickness of the substrate 11 is t and the height of the step 16 is h, it is 0.001 t or more and 0.1 t. It is preferably about the following, more preferably about 0.003 t or more and 0.01 t or less. By setting the height h of the step 16 within the above range, it is possible to further reduce the probability that separation due to stress concentration occurs while suppressing the influence of the step 16 on the vibration characteristics of the vibrating arm 221.

  On the other hand, the width w of the second surface 112 of the substrate 11 of the vibrating arm 221 is not particularly limited, but is preferably about 0.01 t to 1 t, and preferably about 0.03 t to 0.5 t. Is more preferable. By setting the width w of the second surface within the above range, it is possible to further reduce the probability of separation due to stress concentration while suppressing the influence of the step 16 on the vibration characteristics of the vibrating arm 221.

<Manufacturing method of vibration element>
Next, an embodiment of a method for manufacturing a vibration element according to the present invention will be described.
4-6 is sectional drawing for demonstrating embodiment of the manufacturing method of the vibration element of this invention, respectively. 4 to 6 are cross-sectional views corresponding to the line BB in FIG.
The manufacturing method of the resonator element according to this embodiment includes: [1] a substrate 11, a buffer layer (intermediate layer) 12, a lower electrode layer (first electrode layer) 13, a piezoelectric layer 14, and an upper electrode layer (second electrode layer). ) 15 for preparing the laminated body 10 laminated in this order; [2] In the upper surface of the laminated body 10, the region 220 where the vibrating arms 221 and 222 are to be formed, and the electrode 23 in the base 21 A step of superimposing the first mask 271 on the region 230 to be formed, [3] a step of performing a first etching process on the stacked body 10, and [4] removing the first mask 271, and then adding the second mask to the region 220. A step of overlaying the mask 272, [5] a step of performing a second etching process on the stacked body 10, and [6] after removing the second mask 272, a region 226 located between the vibrating arm 221 and the vibrating arm 222 is formed. Third mask 2 to be exposed A 3 a step of superimposing, the step of applying a third etching treatment [7] the laminate 10, and a step of removing [8] the third mask 273. Hereinafter, each process will be described sequentially.

[1]
First, a laminate 10 in which a substrate 11, a buffer layer 12, a lower electrode layer 13, a piezoelectric layer 14, and an upper electrode layer 15 are laminated in this order is prepared (see FIG. 4A).
Examples of the constituent material of the substrate 11 include silicon, ceramics, and glass. Of these, the constituent material of the substrate 11 is preferably silicon. Since the silicon substrate 11 can be precisely processed by a photolithography technique, an etching technique, or the like, it is preferably used for manufacturing the vibration element 1.

  The constituent material of the buffer layer 12 is made of metal oxide such as nickel oxide (NiO), cobalt oxide (CoO), magnesium oxide (MgO), or Ti. Of these, metal oxides are preferably used. By interposing the buffer layer 12 containing a metal oxide between the substrate 11 and the lower electrode layer 13, the adhesion between the substrate 11 and the lower electrode layer 13 is further improved, and the reliability of the vibration element 1 is increased. Can do.

The constituent materials of the lower electrode layer 13 and the upper electrode layer 15 include, for example, gold (Au), gold alloy, platinum (Pt), platinum alloy, aluminum (Al), aluminum alloy, silver (Ag), and silver alloy. , Chromium (Cr), chromium alloy, copper (Cu), molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt (Co), zinc (Zn), zirconium (Zr) and the like.
An arbitrary target layer may be provided between the substrate 11 and the lower electrode layer 13 instead of the buffer layer 12 or in addition to the buffer layer 12.

Among these, as a constituent material of the lower electrode layer 13, platinum or an alloy containing platinum is preferably used. Since these metal materials are excellent in conductivity, they are useful as materials for the lower electrode layer 13. Further, since these metal materials have a relatively low processing rate of the etching process, in the process of exposing the lower electrode layer 13 by the etching process, the timing at which the etching process is finished when the lower electrode layer 13 is exposed is measured. Since it becomes easy, the workability | operativity improves. As a result, the manufacturing efficiency can be increased and the manufacturing yield can be increased.
On the other hand, as the constituent material of the upper electrode layer 15, gold or an alloy containing gold is preferably used. Since these metal materials have a relatively high weather resistance, it is possible to suppress the occurrence of problems such as a decrease in conductivity over time.

Moreover, as a constituent material of the piezoelectric layer 14, for example, aluminum nitride (AlN), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), lead zirconate titanate (PZT), lithium tetraborate ( Examples thereof include oxide materials such as Li ₂ B ₄ O ₇ ) and langasite (La ₃ Ga ₅ SiO ₁₄ ).
Each of these layers is formed by, for example, a physical film formation method such as sputtering or vacuum deposition, a chemical film formation method such as CVD, or a plating method.

[2]
Next, as shown in FIG. 4B, the region 220 in which the detection electrode 151 and the excitation electrode 152 of the vibrating arm 221 are to be formed, the excitation electrode 153 and the detection electrode 154 of the vibrating arm 222 on the upper surface of the stacked body 10. The first mask 271 is formed in the region 220 where the electrode 23 is to be formed and the region 230 where the electrode 23 is to be formed in the base 21.
As the first mask 271, for example, a photoresist film or the like is used. Thus, the first mask 271 having a desired planar view shape can be efficiently formed by performing exposure and development processes.

[3]
Next, a first etching process is performed on the stacked body 10 through the first mask 271. Thereby, the region not covered with the first mask 271 is processed so as to be gradually removed. Then, as shown in FIG. 4C, when the piezoelectric layer 14 is processed halfway through the thickness, the first etching process is finished. By completing the first etching process at such timing, an island-like portion 18 composed of the upper electrode layer 15 and the piezoelectric layer 14 partially protruding is formed in the stacked body 10.
As the first etching process, a wet etching process is also used, but a dry etching process is preferably used. As an etching gas used for the dry etching process, for example, a gas containing CF ₄ , Ar, SF ₆ , O ₂ , C ₄ F _8, or the like can be given.

  When processing is stopped in the middle of the piezoelectric layer 14, the processing depth is not particularly limited, but is preferably about 5% to 70% of the thickness of the piezoelectric layer 14. By setting the processing depth to such a degree, it is possible to prevent the lowering of the mechanical characteristics of the piezoelectric layer 14 itself while ensuring the effect that the upper electrode layer 15 is difficult to peel off. Adhesiveness with the electrode layer 13 can also be ensured.

[4]
Next, the first mask 271 is removed. For example, an ashing process or the like can be used to remove the first mask 271.
Subsequently, a second mask 272 is formed in the region 220 where the vibrating arms 221 and 222 are to be formed.

As the second mask 272, for example, a photoresist film or the like is used.
At this time, as shown in FIG. 5D, it is preferable to form a film so as to cover the second mask 272 from the upper surface of the island-shaped portion 18 to the side surface and the region outside the island-shaped portion 18. Thus, by overlapping the second mask 272 until it reaches the region outside the island-shaped portion 18, the step 17 can be formed in the piezoelectric layer 14 by the second etching process described later.

[5]
Next, a second etching process is performed on the stacked body 10 through the second mask 272. Thereby, the region not covered with the second mask 272 is processed so as to be gradually removed. At this time, since the region 230 where the electrode 23 is to be formed in the base 21 is not covered with the second mask 272, the upper electrode layer 15 and the piezoelectric layer 14 are sequentially removed. Then, as shown in FIG. 5E, when the lower electrode layer 13 is exposed, the second etching process is finished. Thereby, the exposed surface of the lower electrode layer 13 can be formed in the base 21, and this exposed surface becomes the electrode (first electrode) 23 described above.

  Further, the processing proceeds until the lower electrode layer 13 is exposed, while the region 226 between the region where the vibrating arm 221 is to be formed and the region where the vibrating arm 222 is to be formed, and the region where the vibrating arms 221 and 222 are to be formed. In the region 227 between the region where the base portion 21 is to be formed, the thickness at the start of the second etching process is originally thinner than the region 230. For this reason, in these regions 226 and 227, the processing naturally proceeds more than the region 230 in the second etching process. Thus, while processing the lower electrode layer 13 to be exposed, the piezoelectric layer 14, the lower electrode layer 13, the buffer layer 12, and the substrate 11 in the regions 226 and 227 can be processed at the same time. As a result, the processing efficiency can be increased as compared with the case where these processes are performed separately.

Specifically, in these regions 226 and 227, when the processing proceeds until the lower electrode layer 13 is exposed in the region 230, the processing proceeds until the substrate 11 is reached. When the lower electrode layer 13 is exposed in the region 230, the processing is progressing to the middle of the thickness of the substrate 11 in the regions 226 and 227.
In other words, when the second etching process is started, the region 230 is thicker by the island-shaped portion 18, and the processing progress of the region 230 can be delayed by this amount. For this reason, by setting the processing amount in the first etching process so that the thickness of the island-shaped portion 18 is larger than the total thickness of the lower electrode layer 13 and the buffer layer 12, the first etching process is performed. In the two-etching process, the processing can proceed to the middle of the thickness of the substrate 11 in the regions 226 and 227.

Therefore, when the height (thickness) of the island-shaped portion 18 is H and the total of the thickness of the lower electrode layer 13 and the buffer layer 12 is T, it is preferable that T <H is satisfied, and 2T < It is more preferable to satisfy H <10T. Thus, depending on the thickness relationship between the lower electrode layer 13 and the buffer layer 12 and the substrate 11, when the lower electrode layer 13 is exposed in the region 230, the substrate 11 is penetrated in the regions 226 and 227. However, it is possible to proceed to the middle of the substrate 11.
In addition, since the periphery of the region 220 where the vibrating arms 221 and 222 are to be formed is dug down by the second etching process, the island-shaped portion 19 and the step 17 are formed.

[6]
Next, the second mask 272 is removed. For the removal of the second mask 272, for example, an ashing process or the like can be used.
Subsequently, a third mask 273 is formed in the region 220 where the vibrating arms 221 and 222 are to be formed and the region 230 where the electrode 23 is to be formed in the base 21. In other words, a region where the substrate 11 is to be removed, that is, a region 226 between a region where the vibrating arm 221 is to be formed and a region where the vibrating arm 222 is to be formed, and a region where the vibrating arms 221 and 222 are to be formed. A third mask 273 is formed so that a region 227 between the region where the base 21 is to be formed is exposed.

As the third mask 273, for example, a photoresist film or the like is used.
At this time, as shown in FIG. 5 (f), it is preferable to form a film so as to cover the third mask 273 from the upper surface of the island-shaped portion 19 to the side surface and the region outside the island-shaped portion 19. In this way, by overlapping the third mask 273 to reach the region outside the island-shaped portion 19, the piezoelectric layer 14, the lower electrode layer 13, and the buffer layer 12 are processed from the side surfaces in the third etching process described later. Can be prevented. This can prevent the vibration characteristics of the vibrating arms 221 and 222 from being impaired.

[7]
Next, a third etching process is performed on the stacked body 10 through the third mask 273. Thereby, as shown in FIG. 6G, the regions 226 and 227 not covered with the third mask 273 are processed so as to be removed. As a result, the substrate 11 in the regions 226 and 277 is removed. Thereby, the step 16 is formed.

[8]
Next, the third mask 273 is removed. For the removal of the third mask 273, for example, an ashing process or the like can be used. Thereby, as shown in FIG. 6H, the electrode 23 can be exposed and the upper electrode layer 15 can be exposed.
Although not shown in the drawing, the electrodes 24, 25, and 26 formed of the upper electrode layer 15 are also exposed at the base portion 21.
The vibration element 1 is obtained as described above.

In the method for manufacturing a vibration element as described above, the vibration element 1 can be obtained by at least three etching processes. For this reason, the man-hour concerning manufacture can be reduced compared with the past, and a manufacture yield can be raised. That is, the vibration element 1 can be manufactured with fewer steps.
In the conventional manufacturing method, the shape shown in FIG. 8D is changed to the shape shown in FIG. 8E by dry etching. Thereafter, the type of etching gas is changed to change from the shape of FIG. 8E to the shape of FIG. Thus, in the conventional manufacturing method, it was necessary to change etching gas. This is because if the type of etching gas is not changed, the side surfaces of the piezoelectric layer 94, the lower electrode layer 93, and the buffer layer 92 are processed when the shape of FIG. is there.

  On the other hand, in the method for manufacturing a vibration element according to the present embodiment, as shown in FIG. Therefore, the substrate 11 can be processed without changing the type of etching gas. For this reason, the same kind of etching gas can be used in the three etching processes, and gas exchange or the like is not necessary, so that the number of steps can be reduced.

In order to prevent the occurrence of such a problem in the conventional manufacturing method, a process of forming a mask so as to cover the side surface of the island-shaped portion shown in FIG. However, in that case, the number of steps for forming the mask is increased by one, and at least four mask forming steps are required in total, which is not preferable from the viewpoint of manufacturing efficiency.
On the other hand, in the method for manufacturing the resonator element according to the present embodiment, it is possible to suppress the occurrence of problems without changing the type of etching gas and at least three mask forming steps.
The vibration element 1 as described above can be used by being incorporated into various electronic devices.
According to such an electronic device, the reliability can be improved.

<Electronic equipment>
Here, an example of an electronic apparatus including the vibration element of the present invention will be described in detail based on FIGS.
FIG. 7 is a perspective view showing a configuration of a mobile (or notebook) personal computer including the vibration element of the present invention.

In this figure, a personal computer 1100 includes a main body portion 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display portion 100. The display unit 1106 is rotated with respect to the main body portion 1104 via a hinge structure portion. It is supported movably.
Such a personal computer 1100 incorporates the aforementioned vibration element 1 that functions as a gyro sensor.

FIG. 8 is a perspective view showing a configuration of a mobile phone (including PHS) including the vibration element of the present invention.
In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206, and the display unit 100 is disposed between the operation buttons 1202 and the earpiece 1204.
Such a cellular phone 1200 incorporates the above-described vibration element 1 that functions as a gyro sensor.

FIG. 9 is a perspective view showing a configuration of a digital still camera provided with the vibration element of the present invention. In this figure, connection with an external device is also simply shown.
Here, an ordinary camera sensitizes a silver halide photographic film with a light image of a subject, whereas a digital still camera 1300 photoelectrically converts a light image of a subject with an imaging device such as a CCD (Charge Coupled Device). An imaging signal (image signal) is generated.

A display unit is provided on the back of a case (body) 1302 in the digital still camera 1300, and is configured to perform display based on an imaging signal from the CCD. The display unit is a finder that displays an object as an electronic image. Function.
A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side (the back side in the drawing) of the case 1302.
When the photographer confirms the subject image displayed on the display unit and presses the shutter button 1306, the CCD imaging signal at that time is transferred and stored in the memory 1308.

In the digital still camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. As shown in the figure, a television monitor 1430 is connected to the video signal output terminal 1312 and a personal computer 1440 is connected to the input / output terminal 1314 for data communication as necessary. Further, the imaging signal stored in the memory 1308 is output to the television monitor 1430 or the personal computer 1440 by a predetermined operation.
Such a digital still camera 1300 incorporates the aforementioned vibration element 1 that functions as a gyro sensor.

  In addition to the personal computer (mobile personal computer) shown in FIG. 7, the mobile phone shown in FIG. 8, and the digital still camera shown in FIG. Detection device, pointing device, head mounted display, ink jet type ejection device (for example, ink jet printer), laptop personal computer, television, video camera, video tape recorder, navigation device, pager, electronic notebook (including communication function), Electronic dictionary, calculator, electronic game device, game controller, word processor, workstation, video phone, security TV monitor, electronic binoculars, POS terminal, medical device (eg electronic thermometer, blood pressure monitor, blood glucose meter, electrocardiograph) Measuring apparatus, ultrasonic diagnostic apparatus, an electronic endoscope), a fish finder, various measurement devices, gauges (e.g., gages for vehicles, aircraft, and ships), can be applied to a flight simulator or the like.

As mentioned above, although this invention was demonstrated based on embodiment of illustration, this invention is not limited to these.
For example, in the vibration element of the present invention, the configuration of each part can be replaced with an arbitrary configuration that exhibits the same function, and an arbitrary configuration can be added.
Moreover, arbitrary processes can also be added to the manufacturing method of the vibration element of this invention.

DESCRIPTION OF SYMBOLS 1 ... Vibrating element 9 ... Vibrating element 10 ... Laminated body 11 ... Substrate 12 ... Buffer layer 13 ... Lower electrode layer 14 ... Piezoelectric layer 15 ... Upper electrode layer 16 ... Step 17 ... Step 18 …… Island-like portion 19 …… Island-like portion 21 …… Base 23 …… Electrode 24 …… Electrode 25 …… Electrode 26 …… Electrode 91 …… Silicon substrate 92 …… Buffer layer 93 …… Lower electrode layer 94… ... Piezoelectric layer 95 ... Upper electrode layer 96 ... Auxiliary electrode 100 ... Display unit 111 ... First surface 112 ... Second surface 151 ... Detection electrode 152 ... Excitation electrode 153 ... Excitation electrode 154 ... Detection Electrode 220 ... Area 221 ... Vibrating arm 222 ... Vibrating arm 226 ... Area 227 ... Area 230 ... Area 271 ... First mask 272 ... Second mask 273 ... Third mask 9 DESCRIPTION OF SYMBOLS 1 ... Base 902 ... Vibrating arm 941 ... Window part 951 ... Upper electrode layer 952 ... Upper electrode layer 971 ... 1st resist film 972 ... 2nd resist film 973 ... 3rd resist film DESCRIPTION OF SYMBOLS 1100 …… Personal computer 1102 …… Keyboard 1104 …… Main body 1106 …… Display unit 1200 …… Mobile phone 1202 …… Operation buttons 1204 …… Earpiece 1206 …… Speaker 1300 …… Digital still camera 1302 …… Case 1304 …… Light receiving unit 1306 …… Shutter button 1308 …… Memory 1312 …… Video signal output terminal 1314 …… Input / output terminal 1430 …… TV monitor 1440 …… Personal computer

Claims (8)

A base, two vibrating arms provided so as to extend from the base, and a first electrode and a second electrode provided on each of the bases, and between the first electrode and the second electrode A method of manufacturing a vibrating element configured to excite each vibrating arm by applying a voltage,
Preparing a laminate in which a substrate, a first electrode layer, a piezoelectric layer, and a second electrode layer are laminated in this order;
A step of overlaying a first mask on a region of the laminate to form the vibrating arm and a region of the first electrode;
Processing the half-thickness of the piezoelectric layer by applying a first etching process to the stacked body through the first mask;
After removing the first mask, overlaying a second mask on a region where the vibrating arm is formed;
Forming the first electrode by performing a second etching process on the stacked body through the second mask to process the first electrode layer in a region where the first electrode is formed;
After removing the second mask, overlaying a third mask so that a region located between the two vibrating arms is exposed;
A step of performing a third etching process on the stacked body through the third mask to process until a region located between the two vibrating arms penetrates;
Removing the third mask to expose the second electrode layer and forming the second electrode;
A method for manufacturing a vibration element comprising:   2. The method for manufacturing a vibrating element according to claim 1, wherein the third mask is provided so as to overlap a portion extending from a region where the vibrating arm is formed to a region outside the region where the vibrating arm is formed.   3. The method for manufacturing a resonator element according to claim 1, wherein the laminated body is processed to the middle of the thickness of the substrate in a region located between the two vibrating arms by performing the second etching process.   The said laminated body is further provided between the said board | substrate and the said 1st electrode layer, The manufacturing of the vibration element of any one of Claim 1 thru | or 3 provided with the intermediate | middle layer containing a metal oxide. Method.   5. The method for manufacturing a vibration element according to claim 1, wherein the first electrode layer is made of platinum or an alloy containing platinum.   The method for manufacturing a vibration element according to claim 1, wherein the second electrode layer is made of gold or an alloy containing gold.   The method for manufacturing a vibration element according to claim 1, wherein the substrate is made of silicon.   The manufacturing method of the vibration element according to claim 1, wherein the first etching process, the second etching process, and the third etching process are dry etching processes using the same type of etching gas. Method.

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