JPH1096744A - Manufacture of capacitance type acceleration sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method in which harmful gas for an operator is not generated, and the processing schedule is simple. SOLUTION: After forming an approximate shape by silicon etching against the part positions of a silicon substrate 20 corresponding to the parts to be a frame body and first and second weights, a Ni film is formed on one side of the silicon substrate 20 in which a fixed position, namely, a part position to be a cavity after completing is removed, thereafter through etching is executed by reactive ion beam etching (a), and hence the part to be a cavity after completing is formed without using laser beam (b).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for detecting acceleration and angular velocity, and more particularly, to manufacturing of a capacitive acceleration sensor which simplifies manufacturing of a so-called capacitive acceleration sensor and improves safety. About the method.

[0002]

2. Description of the Related Art A so-called capacitive acceleration sensor mainly includes a weight made of a semiconductor member such as silicon supported so as to be displaceable by acceleration, and a solid electrode opposed to the weight with a predetermined gap therebetween. As a component, it is known and well-known as capable of measuring acceleration by detecting a change in capacitance between a weight and a fixed electrode. The applicant of the present application has already proposed various forms. (See Japanese Patent Application Laid-Open No. 6-258314).

[0003]

By the way, this kind of sensor constructed on the basis of such a semiconductor member is produced in large quantities in a small and precise manner by using a so-called semiconductor manufacturing technology, a so-called micro-machining technology or the like. It has advantages such as being possible. However, on the other hand, in particular, in the manufacturing process using the semiconductor manufacturing technology, various chemicals are often used, and therefore, depending on the manufacturing method, a process including a toxic gas that is dangerous to workers is included. There was something. Therefore, in the case of a production process that requires the generation of such harmful gas, since the worker needs to be careful, the entire operation is more difficult than when no toxic gas is generated. In addition to increasing the time required for the production, various safety facilities, such as preventing workers from inhaling the gas and neutralizing and treating harmful gas, are required on the production line, There is a disadvantage that an initial capital investment is required more than that of a manufacturing method that does not cause the problem.

The present invention has been made in view of the above circumstances, and does not generate toxic gas for workers.
Moreover, the present invention provides a method of manufacturing a capacitive acceleration sensor whose processing steps are simple. Another object of the present invention is to provide a method of manufacturing a capacitive acceleration sensor that requires a small number of masks to be used and can reduce the manufacturing time.

[0005]

According to a first aspect of the present invention, there is provided a method for manufacturing a capacitive acceleration sensor, wherein at least a weight made of a semiconductor material is provided inside a frame formed in a frame shape. The weight, which is displaceably supported between the two insulating substrates joined to the frame so as to be sandwiched therebetween, and the weight generated by displacement of the weight according to acceleration, and a fixed electrode formed on the insulating substrate And a method of manufacturing a capacitive acceleration sensor configured to be able to detect a change in capacitance between the frame and the weight of the substrate made of a semiconductor material, at least the frame and the weight to determine the formation location, The substrate is subjected to silicon etching by photolithography, the substrate made of the semiconductor material is placed on one of the two insulating substrates, and the two are bonded by a predetermined bonding method. A metal material having corrosion resistance to reactive ion beam etching is deposited on one surface of the substrate corresponding to a portion of the substrate that should be a gap in a completed state, and the metal material is not deposited By performing through etching by reactive ion beam etching on the portion, a portion that becomes a void in a completed state inside the frame is formed.

[0006] In such a configuration, a portion that becomes a gap inside the frame is formed by reactive ion beam etching. Since it is not necessary to cut the laser light in a predetermined gas atmosphere later, the step of forming a temporary supporting portion can be omitted, and furthermore, the cutting work by the laser light can be omitted. The dangerous gas used at that time is not required, and the safety of work is improved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. The members, arrangements, and the like described below do not limit the present invention, and can be variously modified within the scope of the present invention. First, a configuration example of a capacitive acceleration sensor to which a manufacturing method according to an embodiment of the present invention is applied will be described with reference to FIGS. For convenience of description, in FIG. 2, the left-right direction of the paper is defined as an X-axis, the up-down direction of the paper is defined as a Y-axis, and the front-back direction of the paper is defined as a Z-axis. First, if the overall configuration of this capacitive acceleration sensor is generally described,
This capacitive acceleration sensor has a three-layer structure in which a frame 1 and the like made of silicon are sandwiched between first and second glass substrates 2a and 2b as two insulating substrates. That is, the frame body 1 formed in a frame shape using silicon is configured to be joined to the first and second glass substrates 2a and 2b (see FIG. 2). The center support column 3 and the weight portion 4 supported by the center support column 3 are arranged substantially at the center.

The central support column 3 is formed using silicon in a substantially H-shape in plan view (shape when viewed from the side of the first and second glass substrates 2a and 2b joined to the frame 1). (See FIG. 1), and the first and second glass substrates 2a and 2b face the first and second glass substrates 2a and 2b.
a and 2b, respectively. From the two end surfaces of the connecting portion 3a of the central support column 3 appearing on the XY plane (see FIG. 2), the columnar torsion bar 5
The torsion bar 5 including the connecting portion 3a has a total length in the Z-axis direction slightly longer than that of the side pillar portions 3b and 3c of the central support column 3. . The torsion bar 5 is formed in a columnar shape having a rectangular cross section in the XY plane. The length in the Y-axis direction and the length in the X-axis direction are set in the XY plane of the connecting portion 3a. It is set shorter than that of the end face that appears (see FIG. 2).

[0009] At both ends of the torsion bar 5, the weight 4 disposed inside the frame 1 is connected as described below. That is, the weight portion 4 is formed in a rectangular plate shape disposed at the same distance from the central support column 3 on the left and right sides of the central support column 3 (left and right on the paper surface in FIG. 1) inside the frame body 1. The first and second weights 6 and 7 are further connected to each other so that the first and second weights 6 and 7 are connected to each other from both ends of the side surface facing the center support column 3 side. It has first and second weight connecting arms 8a and 8b integrally extended, and has an overall shape formed in a frame shape (see FIG. 1).

The thickness of the weight portion 4 in the Y-axis direction is the same as the fixed detection electrode 1 of the first and second glass substrates 2a and 2b described later.
The thickness is set to be smaller than the thickness of the frame body 1 in the Y-axis direction so that an appropriate interval is generated between 0a to 10d (see FIG. 2). In addition, both ends of the torsion bar 5 are respectively provided at one side surface of the first and second weight connecting arms 8a and 8b, that is, substantially at the center of the side surface located on the side of the opening 4a formed in the weight portion 4. The first and second weights 6 and 7 are bonded to each other, and the first and second glass substrates 2a and 2
It is in a state of being supported so as to be displaceable between b.

The size of the weight 4 and the position of the weight 4 are set so that a gap is formed between the periphery of the weight 4 and the inner wall of the frame 1. In the embodiment of the present invention, Is the longitudinal axis direction of the weight portion 4 (in FIG. 1, the horizontal direction of the paper).
Is set to be larger than the gap in the short axis direction of the weight portion 4. In the gap between the weight 4 and the frame 1 in the longitudinal axis direction, the frame 1 and the weight 4
Similarly, connection columns 9a to 9d made of silicon and having the same thickness in the Y-axis direction as the frame 1 are provided (see FIGS. 1 and 2). The connection columns 9a to 9d are located at positions where they are joined to lead pieces 11a to 11d provided on fixed detection electrodes 10a to 10d described later, and are located at substantially centers of the connection columns 9a to 9d. Glass substrate 2
a, 2b corresponding to the respective wiring connection holes 12
a to 12j are located. And
As described later, by connecting the lead wires 13 provided in the wiring connection holes 12a to 12j to the connection columns 9a to 9d, the fixed detection electrodes 10a to 10d can be connected to an external circuit (not shown).

On the other hand, the first and second glass substrates 2a, 2
b has substantially the same outer shape and dimensions as those of the frame 1, and has a fixed detection electrode 1
0a to 10d are formed. That is, the first glass substrate 2a has a first surface formed of a conductive member on the surface on the frame 1 side (the surface on the back side of the paper in FIG. 1) formed substantially in the same shape as the weight 4 described above. And the second fixed detection electrode 10a,
10b is disposed at a position facing the weight 4 (see FIGS. 1 and 2). A first fixed detection electrode 10a;
The second fixed detection electrode 10b is located at a position corresponding to substantially the center of the first and second weight connection arms 8a and 8b of the weight 4 described above.
They are disposed so as to face each other via a gap (see FIG. 1). In the first fixed detection electrode 10a, a first lead piece 11a extends from near the position corresponding to the first connection pillar 9a, and its tip portion is connected to the first glass substrate 2a. When the frame body 1 is joined, it is sandwiched between the first glass substrate 2a and the top surface of the first connection pillar 9a. Similarly, the second fixed detection electrode 10
In b, a second lead piece 11b extends from near the position corresponding to the fourth connection pillar 9d, and the first glass substrate 2a and the frame 1 are joined at the tip thereof. At this time, it is sandwiched between the first glass substrate 2a and the top surface of the fourth connection pillar 9d. Further, wiring connection holes 12a to 12e are formed in the first glass substrate 2a at positions corresponding to the connection columns 9a to 9d and at positions corresponding to substantially the center of the center support columns 3, respectively. In each of the wiring connection holes 12a to 12e, a lead 13 made of a conductive material is inserted and filled with a metal material, so-called ohmic contact occurs between the lead 13 and the connection pillars 9a to 9d. It has become.

On the other hand, also in the second glass substrate 2b,
Third and fourth fixed detection electrodes 10c, 1 are provided on the surface of the frame 1 side.
0d is the first and second fixed detection electrodes 10a, 10b.
It is formed and arranged in the same manner (detailed description is omitted). Further, the third fixed detection electrode 10
c, from the vicinity of the position corresponding to the second connection pillar 9b, the third lead piece 11c is connected to the fourth fixed detection electrode 1
In 0d, fourth lead pieces 11d are respectively extended from the vicinity of the position corresponding to the third connection pillar 9c, and the respective leading end portions are formed by the second glass substrate 2b and the frame 1. When they are joined, they are sandwiched between the top surfaces of the corresponding connection pillars 9b and 9c and the second glass substrate 2b. Then, the first glass substrate 2b is also provided with the first glass substrate 2b.
Similarly to the glass substrate 2a, wiring connection holes 12f to 12j are formed at positions corresponding to the connection columns 9a to 9d and the center support column 3.

In this configuration, the capacitor C1 is formed by the first fixed detection electrode 10a and the first weight 6, and the capacitor C2 is formed by the second fixed detection electrode 10b and the second weight 7. A capacitor C3 is formed by the fixed detection electrode 10c and the first weight 6, and a capacitor C4 is formed by the fourth fixed detection electrode 10d and the second weight 7, respectively. The weights 6 and 7 of 2 form part of the weight portion 4 and are electrically in the same potential state. Therefore, as shown in FIG.
One electrode side of each capacitor C1 to C4 (weight 4 corresponds)
Are connected in common, and this is equivalent to a state where the other electrode side is an open end.

The acceleration detection by this capacitive acceleration sensor will be described. For example, assuming that the acceleration acts in the upward direction in FIG. 2, the first and second weights 6, 7
Is displaced in the direction opposite to the direction in which the acceleration acts due to the inertial force until the magnitude of the applied acceleration and the inertial force balance. For this reason, the distance between the first and second fixed detection electrodes 10a and 10b and the first and second weights 6 and 7 is increased, while the third and fourth fixed detection electrodes 10c and 10d are connected to the first and second fixed detection electrodes 10c and 10d. As a result of the decrease in the distance between the second weights 6 and 7, the capacitances of the capacitors C1 and C2 decrease, and the capacitances of the capacitors C3 and C4 increase.
On the other hand, when the acceleration acts in the opposite direction, the capacitances of the capacitors C1 and C2 increase, and the capacitors C3 and C4
Will be reduced. Accordingly, the direction and magnitude of the acceleration can be known from the increase and decrease and the magnitude of the capacitance of each of the capacitors C1, C2, C3 and C4.

Next, a manufacturing process of the capacitive acceleration sensor having the above-described configuration will be described with reference to FIGS. In FIGS. 3 to 6, alphabets are written next to “Pr.” Meaning part (process) as an identification code for distinguishing each process. This corresponds to a flow of a conventional manufacturing process shown in FIG. 11 to be described later and each step used in an explanatory diagram showing a flow of the manufacturing process in the embodiment of the present invention.

First, the first and second glass substrates 2a, 2a
A silicon oxide film (SiO ₂ ) is formed on both surfaces of the silicon substrate 20 used for forming the frame 1 and the weight portion 4 and the like sandwiched between the substrates 2b by wet oxidation which is a method of thermal oxidation (FIG. 3). (A)). For example, this wet oxidation is performed at an ambient temperature of about 1100 ° C. for about 1 hour. Subsequently, in order to form a notch 21 (see FIG. 3B) for indicating the crystal orientation of the silicon substrate, one surface of the silicon substrate 20 is formed by so-called photolithography using a first predetermined mask. The silicon oxide film at a predetermined position on the side is removed (FIG. 3).
(Refer to the symbol (a) in (a)).

Subsequently, only the portion of the silicon substrate 20 corresponding to the portion indicated by the reference character A, for example, K
By performing silicon etching using OH,
A notch 21 is formed, and thereafter, the silicon oxide film is removed by etching using, for example, buffered hydrofluoric acid as an etching solution (see FIG. 3B). The procedure for checking the plane orientation is omitted because it is assumed that (111) has already been specified by the orientation flat of the silicon wafer.

Next, a silicon oxide film is again formed on both surfaces of the silicon substrate 20 by, for example, about 50
It is formed to a thickness of about 00 Å. Then
Using a second predetermined mask, on one surface side of the silicon substrate 20, the entire surface is exposed by photolithography, and the silicon oxide film is etched to have a predetermined shape, and then the resist is removed (FIG. 4 (a)). Further, on the other surface side of the silicon substrate 20, a silicon oxide film is similarly formed in a predetermined shape by photolithography using a second predetermined mask (see FIG. 4A).

Next, portions of silicon that are not covered with the silicon oxide film on both sides of the silicon substrate 20 are removed by about 10 μm from the surface thereof by silicon etching, and the silicon oxide film is removed by etching (FIG. 4). (B)). Subsequently, one surface of the silicon substrate 20, that is, the upper surface of the paper in FIG. 4C (hereinafter, this surface is referred to as “front surface” for convenience, and the opposite surface is referred to as “back surface”). Next, a nickel (Ni) film is formed by sputtering, and the nickel film is etched into a predetermined shape by photolithography using a third predetermined mask (see FIG. 4C).
Here, as for the sputtering, any metal material other than Ni may be used as long as it is a metal material having corrosion resistance to reactive ion etching in a process described later. By the steps up to this point, the frame 1, the center support column 3, the weight 4, and the connection columns 9a to
Each of the formation positions 9d is determined. In other words, a thickness difference in the Z-axis direction (see FIG. 2) of the frame 1, the center support pillar 3, the weight 4, and the connection pillars 9a to 9d is formed by the silicon etching so far. .

Next, the silicon substrate in the state described above is placed on the second glass substrate 2b, and the two are bonded by a known / well-known anodic bonding method (see FIG. 5A). In addition, the joining method does not necessarily need to be the anodic joining method, and of course, other joining methods may be used. Prior to this step, the second glass substrate 2b has been subjected to necessary processing such as formation of the third and fourth fixed detection electrodes 10c and 10d and formation of the wiring connection holes 12f to 12j. Shall be. Subsequently, reactive ion etching (RI) (known as a kind of dry etching)
E: Reactive Ion Etching, so-called through-etching is performed in the thickness direction of the silicon substrate (the vertical direction in FIG. 5) to remove silicon at a predetermined location, and then remove the nickel film by etching. Then, washing and drying are performed (FIG. 5A,
(B)). By the penetration etching by the RIE, the frame body 1, the center support pillar 3, the weight portion 4, and the like sandwiched between the first glass substrate 2a and the second glass substrate 2b are formed. In other words, by the penetration etching by the RIE, a portion to be a void after completion is formed inside the frame 1.

Next, the first glass substrate 2a is bonded by an anodic bonding method (see FIG. 5C). Here, the first glass substrate 2a is subjected to necessary processing such as formation of the first and second fixed detection electrodes 10a and 10b and formation of the wiring connection holes 12a to 12e before this step. It has been done. Also, the joining method does not necessarily need to be the anodic joining method, and of course, other joining methods may be used. Subsequently, the upper surface of the first glass substrate 2a (FIG. 6)
, Aluminum is deposited on the upper side of the paper by sputtering, and thereafter, the wiring connection holes 12a to 12e are formed by photolithography using a fourth predetermined mask.
The aluminum deposited on the other parts is removed (see FIG. 6A). Finally, the lead wire 13 is inserted into each of the wiring connection holes 12a to 12e and filled with solder to attach the lead wire, thereby completing the capacitive acceleration sensor (see FIG. 6B). .

As described above, the manufacturing process according to the embodiment of the present invention differs from the conventional one in that a gas toxic to the operator,
In particular, NF ₃ gas, which has conventionally been used for cutting silicon that has been temporarily connected between the connection pillars 9a to 9d and the frame body 1 by a laser beam, is not required.
It is possible to manufacture a capacitive acceleration sensor by using only one mask.

Next, in order to clarify how simple the manufacturing process described above is compared with the conventional manufacturing process, the flow of the manufacturing process described above with reference to FIG. The difference in the flow of the manufacturing process will be described, and the conventional manufacturing process will be generally described with reference to FIGS. First, FIG.
9 shows the flow of the manufacturing process according to the embodiment of the present invention described above together with the flow of the conventional manufacturing process. That is, each main process of the manufacturing process is referred to as a part (in FIG. 11, denoted as “Pr.”). It consists of 16 steps up to P, and requires seven masks.

On the other hand, the manufacturing process according to the above-described embodiment of the present invention includes all of the parts A to D, the parts Q to S, and the parts N to P.
It consists of zero steps (the steps of parts A to D and parts N to P are common to the conventional manufacturing process), and requires only four masks. In FIG. 11, “Mask” is written beside the step requiring a mask, and “Mask” is used for those common to the conventional manufacturing process and the manufacturing process in the embodiment of the present invention. Numbers are assigned in ascending order from 1 next to the letters, and those in the manufacturing process according to the embodiment of the present invention are further distinguished by adding an alphabetic letter A beside the numbers. Further, in FIGS. 3 to 6 and FIGS. 7 to 10 which will be described later, the corresponding mask numbers are written in parentheses beside the drawings showing the steps in which the mask shown in FIG. 11 is used. . In FIGS. 3 to 6 and FIGS. 7 to 10 described later, the same reference numerals (Pr. A, etc.) as those used in FIG. It is.

Next, in order to further clarify the difference between the above-described manufacturing process in the embodiment of the present invention and the conventional manufacturing process, the conventional manufacturing process will be generally described with reference to FIGS. I decided to. First, the parts A to D and the parts N to P (see FIG. 11) in the conventional manufacturing process are the same as those in the above-described embodiment of the present invention (see FIGS. 3 and 4).
(See (a), (b) and FIG. 6), so a detailed description is omitted here, and parts E through M will be described.

That is, after the processing of Part D, a silicon oxide film (SiO ₂ ) is formed on both surfaces of the silicon substrate 20 by about 10700 angstroms by wet oxidation which is one of thermal oxidation. Subsequently, by photolithography, using a third predetermined mask in total,
Silicon oxide films on both sides are formed in a predetermined shape (FIG. 7).
(A)). Next, a predetermined portion of the silicon oxide film is etched using a fourth predetermined mask by photolithography, so that the thickness of the silicon oxide film in that portion is reduced to, for example, about 4500 angstroms. (See FIG. 7B).

Subsequently, the portion where the silicon substrate 20 is exposed is subjected to silicon etching, and a predetermined depth (about 10 μm and about 32
μm), the silicon oxide film is further etched to form a silicon oxide film having a thickness of about 6000 angstroms (see FIG. 7C). Next, silicon is removed by silicon etching so that silicon at a predetermined location is cut, and portions corresponding to the frame 1, the weight 4, and the like are formed (see FIG. 8A). In this step, a portion of the silicon is left between the connection columns 9a to 9d and the frame 1, and a temporary support portion for temporarily fixing the connection columns 9a to 9d and the frame 1 is provided. 22 (FIG. 8A)
The temporary support portion 22 is cut by a laser beam in a step described later. Although FIG. 8A shows that the silicon oxide film has been removed, the removal of the silicon oxide film is performed immediately before a bonding process with a glass substrate by an anodic bonding method described later. ,
Until then, the silicon oxide film is left in the formed state.

Next, the steps from Part I to Part M (corresponding to FIGS. 8B to 9B) are the first and second steps.
8 (b) to 9 (b) since the manufacturing steps of the two glass substrates 2a and 2b are the same.
Shows the manufacturing process of one glass substrate (for example, the first glass substrate 2a), and the following description will also explain one manufacturing process and replace the description of the other glass substrate. . First glass substrate 2a (or second glass substrate 2a)
In the glass plate to be the glass substrate 2b), wiring connection holes 12a to 12e are formed at predetermined portions by using electrolytic discharge machining.
(Or 12f to 12j) (FIG. 8)
(B)). Then, by photolithography
Using a fifth predetermined mask, a predetermined photoresist film is formed on one surface side of the glass plate (see FIG. 8C), and then ITO (indium tin oxide) is sputtered. The fixed detection electrodes 10a and 10b made of ITO are vapor-deposited on predetermined portions where no photoresist film is formed to a film thickness of about 2000 Å.
(Or 10c, 10d) is formed (FIG. 8).
(D)).

Next, the fixed detection electrodes 10a, 10b are formed by photolithography using a sixth mask in total.
A photoresist film is formed in a predetermined shape on the surface side on which the fixed detection electrodes 10c and 10d are formed, and for example, an alloy of titanium and platinum (Ti / Pt) is vapor-deposited at a predetermined position,
Then, by removing the unnecessary photoresist film,
The drawer pieces 11a and 11b (or 11e and 11d) are formed (see FIG. 9A). And the second
The frame 1, the weight 4 and the like manufactured in the steps up to FIG. 8A are placed on the glass substrate 2b described above, and the second glass substrate 2b and the frame 1 and the like are formed by anodic bonding. The bonding is performed, and the temporary support portion 22 is cut using a YAG laser, for example, in an NF ₃ gas atmosphere (see FIG. 9B).

Thus, the processes up to the part M shown in FIG. 11 are completed. The subsequent steps from Part N to Part P are exactly the same as those already described in the manufacturing process according to the embodiment of the present invention (FIG. 5C).
And FIG. 6), and a repeated description here will be omitted. In the process of Part N, the total number of masks used in the conventional manufacturing process is the seventh, but in the manufacturing process according to the embodiment of the present invention, the fourth mask is used as described above. Of the mask.

During the conventional manufacturing process described above,
The NF ₃ gas used in the cutting work of the temporary support portion 22 by the AG laser is harmful to the human body. In the work, it is necessary to prepare production facilities so as not to be sucked or the like. You need to be very careful.

Next, a second example of the manufacturing process according to the embodiment of the present invention will be described with reference to FIGS. In the second example, as shown in FIG. 11, parts A to L are the same as the conventional manufacturing process. Parts N to P are the same as in the related art. That is, in the second example, after the process of Part L, on the second glass substrate 2b,
The frame 1 and the like manufactured in the steps up to Part H (see FIG. 8A) are placed, and the second glass substrate 2b and the frame 1 and the like are joined by an anodic bonding method (FIG. 10). Then, a glass mask 23 is temporarily mounted on the frame 1 and the like, and a sixth mask (part L in FIG. 11 in FIG. 11) is formed by reactive ion beam etching (RIE).
"Mask.6A" to distinguish it from the mask used in the process
(Notation), and the temporary support portion 22 is cut to complete the process of Part T (see FIG. 10). Here, when the glass mask 23 is placed on the frame 1 or the like, a hole 24 is formed at a position corresponding to the position of the temporary support portion 22. RIE can be performed on the support portion 22. Since the processes of parts A to L and N to P are the same as those described above, description thereof will be omitted. This second
In the case of the example, unlike the conventional manufacturing process, the temporary support portion 22 is cut by the reactive ion beam etching, and the feature is that the cutting work by the conventional laser beam is eliminated. It is.

[0034]

As described above, according to the present invention,
By using a configuration that does not use a dangerous gas as in the past and that can simplify the process, unlike the conventional process, it does not include a laser beam processing process. In addition, since the dangerous gas used as the atmosphere is not required, the worker can perform a safe operation without being exposed to the dangerous gas, and the high safety is secured. Further, unlike the related art, there is no need to form a kind of temporary support portion for temporarily supporting a portion to be cut by the laser beam, so that the number of steps can be reduced, and the manufacturing time can be reduced. And the number of necessary masks is reduced, so that the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing a disassembled configuration of a capacitive acceleration sensor according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the capacitive acceleration sensor taken along the line AA in FIG.

FIG. 3 is a schematic view schematically showing steps in a manufacturing process of the capacitive acceleration sensor according to the embodiment of the present invention.

FIG. 4 is a schematic view schematically showing a manufacturing process following the manufacturing process shown in FIG.

FIG. 5 is a schematic view schematically showing a manufacturing process following the manufacturing process shown in FIG. 4;

FIG. 6 is a schematic view schematically showing a manufacturing process following the manufacturing process shown in FIG. 5;

FIG. 7 is a schematic view schematically showing a part of a manufacturing process in a conventional manufacturing process.

FIG. 8 is a schematic diagram schematically showing a manufacturing process following the manufacturing process shown in FIG. 7;

FIG. 9 is a schematic view schematically showing a manufacturing process following the manufacturing process shown in FIG. 8;

FIG. 10 is a schematic view schematically showing a part of a manufacturing process in a second example of the manufacturing process of the capacitive acceleration sensor according to the embodiment of the present invention.

FIG. 11 is a flowchart showing a flow of a manufacturing process according to the embodiment of the present invention and a flow of a conventional manufacturing process.

FIG. 12 is an equivalent circuit of the capacitive acceleration sensor according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Frame body 3 ... Center support pillar 3a ... Connection part 3b, 3c ... Side pillar part 4 ... Weight part 5 ... Torsion bar 6 ... First weight 7 ... Second weight 9a ... First connection pillar 9b ... First 2 connection pillar 9c 3rd connection pillar 9d 4th connection pillar 10a 1st fixed detection electrode 10b 2nd fixed detection electrode 10c 3rd fixed detection electrode 10d 4th fixed detection electrode

Claims (3)

[Claims] 1. A weight made of at least a semiconductor material is displaceable inside a frame formed in a frame shape between two insulating substrates joined to the frame so as to sandwich the frame. And a capacitance-type acceleration sensor configured to be able to detect a change in capacitance between the weight caused by displacement of the weight according to acceleration and a fixed electrode formed on the insulating substrate. The method according to claim 1, wherein the substrate is subjected to silicon etching by photolithography in order to determine at least the positions where the frame and the weight are formed on the substrate made of a semiconductor material. One of the two insulating substrates is placed on one of the insulating substrates, and the two are bonded by a predetermined bonding method, and one of the substrates corresponding to a portion of the substrate to be a gap in a completed state By depositing a metal material having corrosion resistance to reactive ion beam etching on the surface of the substrate, and performing through etching by reactive ion beam etching on a portion where the metal material is not deposited. And forming a portion that becomes a gap in a completed state inside the frame body. 2. After penetrating etching by reactive ion beam etching, a metal material having corrosion resistance to reactive ion beam etching is removed by etching, and the other of the two insulating substrates is Manufacturing the capacitive acceleration sensor by joining the frame and a member disposed inside the frame by sandwiching the frame with the frame by a predetermined joining method. Method. 3. The method according to claim 1, wherein the predetermined bonding method is an anodic bonding method.