WO2009081459A1 - Manufacturing method of packaged micro moving element and the packaged micro moving element - Google Patents

Abstract

A packaged device (X1) comprises a micro moving element (Y) having movable portions (10, 61) and terminal portions (31b, 31e), a first packaging member (80) having a through hole (82a), and a second packaging member (90). The packaged device is manufactured by a step of bonding a first packaging wafer including a plurality of first packaging member forming blocks on one surface of a device wafer including a plurality of micro moving element forming blocks, a step of bonding a second packaging wafer including a plurality of second packaging member forming blocks on the other surface of the device wafer, and a step of forming a through hole ineach of the first packaging member forming blocks as well as thinning the first packaging wafer.

Description

Packaged micro movable element manufacturing method and packaged micro movable element

The present invention relates to a method of manufacturing a micro movable element such as an acceleration sensor or an angular velocity sensor packaged with a movable part, and a packaged micro movable element.

In recent years, in various technical fields, devices having micro structures formed by micromachining technology have been applied. Such an element includes a sensing device (an angular velocity sensor, an acceleration sensor, etc.) having a minute movable part or a swinging part. Such a sensing device is used, for example, in applications such as a camera shake prevention function of a video camera or a mobile phone with a camera, a car navigation system, an airbag opening timing system, and a posture control system such as a car or a robot.

A sensing device with a micro structure includes, for example, a swingable movable part, a fixed part, a connecting part that connects the movable part and the fixed part, a drive electrode pair for driving the movable part, and a movable part A detection electrode pair for detecting operation and displacement is provided, and a plurality of terminal portions for external connection. In such a sensing device, adhesion of foreign matter or dust to the electrode or damage to the electrode can be a cause of deterioration in operating performance. Therefore, packaging may be performed at the wafer level in the manufacturing process of the sensing device in order to avoid adhesion of foreign matter or dust to the electrode or damage to the electrode. Techniques related to packaging are described in, for example, the following Patent Documents 1 to 3.

JP 2001-196484 A JP 2005-129888 A JP 2005-251898 A

Some packaged sensing devices include a plurality of conductive plugs that penetrate through a packaging member and are electrically connected to a plurality of terminal portions for external connection of the sensing device. In this type of packaged sensing device, the sensing device is electrically connected to the outside through these conductive plugs. However, in order to manufacture this type of packaged sensing device, it is necessary to go through a number of steps in order to embed a conductive plug in the packaging member. Therefore, a packaged sensing device including a conductive plug that penetrates the packaging member is not preferable in terms of reducing manufacturing costs.

Some packaged sensing devices have a structure in which a plurality of terminal portions for external connection of the sensing device are exposed outside the package. In this type of packaged sensing device, for example, wire bonding can be performed directly on these terminal portions, so that it is not necessary to embed the conductive plug as described above in the packaging member. However, when this type of packaged sensing device is manufactured while realizing wafer level packaging, it is difficult to obtain a sufficiently thin package or packaged sensing device.

Conventionally, in order to manufacture this type of packaged sensing device while realizing wafer level packaging, for example, a device wafer including a plurality of device forming sections each of which a sensing device is to be formed; A packaging wafer to be separated into a packaging member is prepared, and after necessary processing is performed on the packaging wafer, a terminal portion of each sensing device is formed on the device wafer. Bonded to the side. Prior to the bonding step, a plurality of openings penetrating the packaging wafer are formed in advance on the packaging wafer so that at least a part of each terminal portion is exposed to the outside while being bonded to the device wafer. The openings are formed in the packaging wafer in a range and number corresponding to the sizes and positions of a large number of terminal portions formed in the device wafer. A packaging wafer having a relatively large area becomes considerably brittle when such an opening is formed. Therefore, the packaging wafer in which the opening is formed is easily broken and difficult to handle. In the manufacturing process described above, the packaging wafer is thick enough to maintain a predetermined strength or higher even if the opening is formed so that the packaging wafer is not easily damaged before being bonded to the device wafer. It is necessary to adopt. Therefore, in the conventional technology, when a packaged sensing device having a structure in which a plurality of terminal portions for external connection of the sensing device are exposed to the outside of the package is manufactured while realizing wafer level packaging, the package is sufficiently thin. It is difficult to obtain.

The present invention has been conceived under such circumstances, and an object of the present invention is to provide a packaged micro movable device manufacturing method and a packaged micro movable device suitable for reducing the package thickness. .

According to the first aspect of the present invention, a micro movable element having a movable part and a terminal part for external connection, and a first packaging having a through hole at a position corresponding to the terminal part and joined to the micro movable element. A method is provided for manufacturing a packaged micro movable device comprising a member and a second packaging member joined to the micro movable device on the opposite side of the first packaging member. In this element, at least a part of the terminal portion faces the through hole. The method includes a first bonding step, a second bonding step, a first packaging wafer processing step, and a dicing step. In the first bonding step, the first surface side of a device wafer having a first surface and a second surface opposite to the first surface and including a plurality of micro movable element forming sections for forming micro movable elements And bonding a first packaging wafer including a plurality of first packaging member forming sections for forming the first packaging member. In the second bonding step, a second packaging wafer including a plurality of second packaging member forming sections for forming the second packaging member is bonded to the second surface side of the device wafer. The first bonding step may be performed before the second bonding step, or the second bonding step may be performed before the first bonding step. Through the first and second bonding steps, packaging at the wafer level is achieved. In the first packaging wafer processing step, through holes are formed in each first packaging member forming section, and the first packaging wafer is thinned. In the dicing process, the stacked structure including the device wafer, the first packaging wafer, and the second packaging wafer is cut. Through the dicing process, individual pieces in a state where each micro movable element is packaged are obtained. The individual or packaged micro movable element has a structure in which at least a part of a terminal portion for external connection of the micro movable element is exposed outside the package.

The first packaging wafer in the present method includes a plurality of sections for forming a first packaging member in a packaged micro movable element to be manufactured. The first packaging wafer used in the first bonding step The thickness of the first packaging member is not the same as the thickness of the first packaging member, and a first packaging wafer thicker than the first packaging member is used for the first bonding step. After wafer level packaging is achieved (after both the first and second bonding steps are completed), processing is performed on the first packaging wafer that is bonded to the device wafer and is less likely to be damaged. By being applied, the first packaging wafer is thinned to a desired degree (first packaging wafer processing step). The first packaging member is derived from the first packaging wafer thinned in this way. As described above, the present method easily reduces the thickness of the first packaging member, and is therefore suitable for reducing the thickness of the packaged micro movable element or package to be manufactured.

In addition, the first packaging wafer used for the first bonding step in the present method is less likely to be damaged and easier to handle than the packaging wafer with an opening used for the bonding step in the conventional method described above. This is because the first packaging wafer provided for the first bonding step in the present method has no opening that penetrates the wafer. The through hole to be formed in the first packaging member to expose the terminal portion of the micro movable element to the outside of the package is formed after wafer level packaging is achieved (after both the first and second bonding steps are completed). ), Formed by processing the first packaging wafer which is in a state of being hardly damaged by being bonded to the device wafer (first packaging wafer processing step).

As described above, the packaged micro movable element manufacturing method of the present invention is suitable for reducing the thickness of the resulting package while ensuring the strength or ease of handling of the first packaging wafer before being bonded to the device wafer. It is.

Preferably, before the first bonding step, a concave portion is formed at a through hole forming portion in each first packaging member forming section of the first packaging wafer. According to such a configuration, it is easy to align the device wafer and the first packaging wafer in the first bonding step by using the concave portion.

Preferably, the first packaging member forming section includes a first region and a second region including the through hole forming portion and the periphery thereof, and the first packaging wafer processing step is performed with respect to the second region. It includes a first step of forming a through-hole while thinning the second region by performing an anisotropic etching process, and a second step of thinning the first region while further thinning the second region. Alternatively, in the first packaging wafer processing step, the through holes may be formed while the first packaging wafer is thinned. According to these methods, in the first packaging wafer processing step, the first packaging wafer can be appropriately thinned, and a through hole or an opening that penetrates the first packaging wafer can be appropriately formed.

Preferably, before the first bonding step, a recess that will be opposed to the movable portion of the micro movable element is formed in each first packaging member forming section of the first packaging wafer. Such a configuration is suitable for avoiding that the movable portion that swings when the micro movable element is driven contacts the first packaging member.

Preferably, prior to the second bonding step, a recess that will face the movable portion of the micro movable element is formed in each second packaging member forming section of the second packaging wafer. Such a configuration is suitable for avoiding that the movable portion that swings when the micro movable element is driven contacts the second packaging member.

Preferably, in the first packaging wafer processing step, at least the opening end of the through hole is formed in a shape that widens as the distance from the micro movable element increases. Such a configuration is suitable for wire bonding to a terminal portion exposed outside the package through the through hole of the first packaging member of the packaged micro movable element to be manufactured.

Preferably, in the first bonding step, the device wafer and the first packaging wafer are bonded via an insulating film. Such a configuration is suitable for electrically separating the device wafer and the first packaging wafer.

Preferably, in the second bonding step, the device wafer and the second packaging wafer are bonded via an insulating film. Such a configuration is suitable for electrically separating the device wafer and the second packaging wafer.

Preferably, the device wafer has a laminated structure including a first layer having a first surface, a second layer having a second surface, and an intermediate layer between the first and second layers. Prior to the bonding step, a processing step of performing an etching process on the first layer is performed using a mask pattern provided on the first surface as a mask. In this case, preferably, after the first bonding step and before the second bonding step, a processing step of performing an etching process on the second layer using the mask pattern provided on the second surface as a mask. Do.

According to a second aspect of the present invention, a packaged micro movable element is provided. The packaged micro movable element includes a micro movable element having a movable part and a terminal part for external connection, and a first packaging member having a through hole at a position corresponding to the terminal part and joined to the micro movable element. And a second packaging member joined to the micro movable element on the side opposite to the first packaging member. The micro movable element having such a configuration can be appropriately manufactured by the method according to the first aspect of the present invention.

In a preferred embodiment of the second aspect of the present invention, the first packaging member includes a first portion and a second portion that is thinner than the first portion, including the through hole formation portion and its periphery. Such a configuration is suitable for wire bonding to the terminal portion exposed outside the package through the through hole of the first packaging member.

Preferably, the first packaging member has a concave portion at a location facing the movable portion of the micro movable element. Preferably, the 2nd packaging member has a recessed part in the location facing the movable part of a micro movable element. Preferably, at least the open end of the through hole has a shape that widens as the distance from the micro movable element increases. Preferably, an insulating film is interposed between the micro movable element and the first packaging member and / or between the micro movable element and the second packaging member.

The present micro movable element preferably includes a fixed portion and a connecting portion for connecting the fixed portion and the movable portion in addition to the movable portion and the terminal portion, and the movable portion is swingable. More preferably, the micro movable element is a sensing device such as an angular velocity sensor or an acceleration sensor.

FIG. 1 is a partially omitted plan view of a packaged device according to a first embodiment of the present invention. FIG. 2 is another partially omitted plan view of the packaged device according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a cross-sectional view taken along line VV in FIG. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. FIG. 9 shows some steps in the method of manufacturing the packaged device shown in FIG. FIG. 10 illustrates a process subsequent to FIG. FIG. 11 shows a process following FIG. FIG. 12 shows a process following FIG. FIG. 13 shows a process subsequent to FIG. FIG. 14 shows a method for manufacturing one packaging wafer in the first embodiment. FIG. 15 is a partially omitted plan view of a packaged device according to the second embodiment of the present invention. FIG. 16 is another partially omitted plan view of the packaged device according to the second embodiment of the present invention. 17 is a cross-sectional view taken along line XVII-XVII in FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. 19 is a cross-sectional view taken along line XIX-XIX in FIG. 20 is a cross-sectional view taken along line XX-XX in FIG. 21 is a cross-sectional view taken along line XXI-XXI in FIG. 22 is a cross-sectional view taken along line XXII-XXII in FIG. FIG. 23 shows some steps in the method of manufacturing the packaged device shown in FIG. FIG. 24 shows a step that follows FIG. FIG. 25 shows a step that follows FIG. FIG. 26 shows a step that follows FIG. FIG. 27 shows a step that follows FIG. FIG. 28 shows a method of manufacturing one packaging wafer in the second embodiment.

1 to 8 show a packaged device X1 according to the first embodiment of the present invention. FIG. 1 is a partially omitted plan view of the packaged device X1, and FIG. 2 is another partially omitted plan view of the packaged device X1. 3 to 8 are cross-sectional views taken along line III-III, line IV-IV, line VV, line VI-VI, line VII-VII, and line VIII-VIII in FIG. 1, respectively.

The packaged device X1 includes a sensing device Y, a packaging member 80 (omitted in FIG. 1), and a packaging member 90 (omitted in FIG. 2).

The sensing device Y includes a land portion 10, an inner frame 20, an outer frame 30, a pair of connecting portions 40, a pair of connecting portions 50, a detection electrode 61 (not shown in FIG. 1), and a detection electrode 62A. , 62B (not shown in FIG. 2) and driving electrodes 71A, 71B, 72A, 72B, and configured as an angular velocity sensor. The sensing device Y is manufactured by processing a wafer which is a so-called SOI (silicon on insulator) substrate by a bulk micromachining technology such as a MEMS technology. The wafer has, for example, a laminated structure composed of first and second silicon layers and an insulating layer between the silicon layers, and each silicon layer is given predetermined conductivity by doping impurities. In FIG. 1, a portion that is derived from the first silicon layer and protrudes from the insulating layer toward the front side of the drawing is indicated by hatching. In FIG. 2, the portion derived from the second silicon layer is directed to the front side of the drawing from the insulating layer. The protruding part is indicated by hatching.

The land part 10 is a part derived from the first silicon layer. As shown in FIGS. 3 and 5, a conductive plug 11 is embedded in the land portion 10.

For example, as shown in FIG. 3, the inner frame 20 includes a first layer portion 21 derived from the first silicon layer, a second layer portion 22 derived from the second silicon layer, and an insulating layer 23 therebetween. It has the laminated structure which becomes. As shown in FIG. 1, the first layer portion 21 includes portions 21a, 21b, 21c, 21d, 21e, and 21f. The portions 21a to 21f are separated from each other via a gap.

As shown in FIGS. 3 and 4, for example, the outer frame 30 includes a first layer portion 31 derived from the first silicon layer, a second layer portion 32 derived from the second silicon layer, and an insulating layer therebetween. 33. As shown in FIG. 1, the first layer portion 31 includes portions 31a, 31b, 31c, 31d, 31e, 31f, 31g, and 31h. The portions 31a to 31h are separated from the surroundings through a gap, and constitute a terminal portion for external connection in the sensing device Y.

The pair of connecting portions 40 are portions for connecting the land portion 10 and the inner frame 20 and are derived from the first silicon layer. Each connecting portion 40 includes two torsion bars 41. As shown in FIG. 1, each torsion bar 41 of one connecting portion 40 is connected to the land portion 10 and to the portion 21a of the first layer portion 21 of the inner frame 20, and the land portion 10 and the portion 21a are electrically connected. Connect. Each torsion bar 41 of the other connecting portion 40 is connected to the land portion 10 and connected to the portion 21d of the first layer portion 21 of the inner frame 20 to electrically connect the land portion 10 and the portion 21d. Such a pair of connecting portions 40 defines an axis A <b> 1 of the swinging motion of the land portion 10. Each connecting portion 40 including two torsion bars 41 whose intervals gradually increase from the inner frame 20 side to the land portion 10 side is suitable for suppressing generation of unnecessary displacement components in the swinging operation of the land portion 10. It is.

The pair of connecting portions 50 are portions for connecting the inner frame 20 and the outer frame 30 and are derived from the first silicon layer. Each connecting portion 50 includes three torsion bars 51, 52, and 53. As shown in FIG. 1, the torsion bar 51 in one connecting portion 50 is connected to the portion 21 a of the first layer portion 21 of the inner frame 20 and to the portion 31 a of the first layer portion 31 of the outer frame 30. The portions 21a and 31a are electrically connected, and the torsion bar 52 is connected to the portion 21b of the first layer portion 21 of the inner frame 20 and connected to the portion 31b of the first layer portion 31 of the outer frame 30 to be the portion 21b. , 31b are electrically connected, and the torsion bar 53 is connected to the portion 21c of the first layer portion 21 of the inner frame 20 and is connected to the portion 31c of the first layer portion 31 of the outer frame 30 to the portions 21c, 31c. Are electrically connected. The torsion bar 51 in the other connecting portion 50 is connected to the portion 21d of the first layer portion 21 of the inner frame 20 and connected to the portion 31d of the first layer portion 31 of the outer frame 30 to electrically connect the portions 21d and 31d. The torsion bar 52 is connected to the portion 21e of the first layer portion 21 of the inner frame 20 and is connected to the portion 31e of the first layer portion 31 of the outer frame 30 to electrically connect the portions 21e and 31e. The torsion bar 53 is connected to the portion 21 f of the first layer portion 21 of the inner frame 20 and is connected to the portion 31 f of the first layer portion 31 of the outer frame 30 to electrically connect the portions 21 f and 31 f. Such a pair of connecting portions 50 defines an axis A <b> 2 of the swinging motion of the inner frame 20. Each connecting portion 50 including two torsion bars 51 and 53 whose intervals gradually increase from the outer frame 30 side to the inner frame 20 side suppress the generation of unnecessary displacement components in the swinging operation of the inner frame 20. It is suitable for.

The detection electrode 61 is a part derived from the second silicon layer. As shown in FIGS. 3 and 5, the detection electrode 61 is joined to the land portion 10 via the insulating layer 12 derived from the above insulating layer, and penetrates the land portion 10 and the insulating layer 12. The detection electrode 61 and the land portion 10 are electrically connected via the conductive plug 11.

The detection electrode 62A is a part derived from the first silicon layer. As shown in FIG. 5, the detection electrode 62 </ b> A extends from the portion 21 b of the first layer portion 21 of the inner frame 20 to the land portion 10 side and has a portion facing the detection electrode 61. The detection electrode 62A has a plurality of openings.

The detection electrode 62B is a part derived from the first silicon layer. As shown in FIG. 5, the detection electrode 62 </ b> B extends from the portion 21 e of the first layer portion 21 of the inner frame 20 toward the land portion 10 and has a portion facing the detection electrode 61. The detection electrode 62B has a plurality of openings.

The driving electrode 71A is a comb-shaped electrode derived from the first silicon layer, and includes a plurality of electrode teeth 71a extending from the portion 21c in the inner frame 20, as shown in FIG. The plurality of electrode teeth 71a are parallel to each other, for example, as shown in FIGS.

The driving electrode 71B is a comb-shaped electrode derived from the first silicon layer, and includes a plurality of electrode teeth 71b extending from the portion 21f of the inner frame 20. The plurality of electrode teeth 71b are parallel to each other.

The driving electrode 72A is a comb-shaped electrode derived from the first silicon layer, and is arranged to face the driving electrode 71A and includes a plurality of electrode teeth 72a extending from the portion 31g in the outer frame 30. The plurality of electrode teeth 72a are parallel to each other as shown in FIGS. 1 and 6, for example, and are also parallel to the electrode teeth 71a of the drive electrode 71A described above.

The driving electrode 72B is a comb-shaped electrode derived from the first silicon layer, and is arranged to face the driving electrode 71B and includes a plurality of electrode teeth 72b extending from the portion 31h in the outer frame 30. The plurality of electrode teeth 72b are parallel to each other, and are also parallel to the electrode teeth 71b of the drive electrode 71B described above.

The packaging member 80 is joined to the first layer portion 31 side of the outer frame 30 of the sensing device Y, and has a recess 80a at a location corresponding to the movable portion of the sensing device Y. Further, for example, as shown in FIG. 3 and FIG. 5, the packaging member 80 has a first part 81 and a second part 82 thinner than the first part 81, and the second part 82 has a through hole 82 a. Is formed. The thickness of the first portion 81 is, for example, 50 to 200 μm. The thickness of the second portion 82 is, for example, 20 to 100 μm as long as it is smaller than the thickness of the first portion 81. The diameter of the through hole 82a is, for example, 20 to 100 μm. As shown in FIGS. 3, 5, 7, and 8, each of the portions 31a to 31h, which are external connection terminal portions in the sensing device Y, partially faces the through hole 82a. That is, all of the portions 31a to 31h as the terminal portions are partially exposed outside the package through the through holes 82a.

The packaging member 90 is joined to the second layer portion 32 side of the outer frame 30 of the sensing device Y, and has a recess 90a at a location corresponding to the movable portion of the sensing device Y. The sensing device Y is sealed by these packaging members 80 and 90.

The packaged device X1 having the above configuration can be connected to an external circuit by wire bonding. Specifically, the terminal portions (parts 31a to 31h) exposed in the through holes 82a of the packaging member 80 and predetermined terminal portions of the external circuit can be electrically connected by wire bonding.

When driving the sensing device Y as an angular velocity sensor, the movable part (land part 10, inner frame 20, driving electrodes 61, 62A, 62B) is oscillated around the axis A2 at a predetermined frequency or cycle. This swinging operation is realized by alternately repeating voltage application between the drive electrodes 71A and 72A and voltage application between the drive electrodes 71B and 72B. At that time, application of a potential to the driving electrode 71A can be realized via the portion 31c in the outer frame 30, the torsion bar 53 of one connecting portion 50, and the portion 21c in the inner frame 20. The application of a potential to the driving electrode 71B can be realized through the portion 31f in the outer frame 30, the torsion bar 53 of the other connecting portion 50, and the portion 21f in the inner frame 20. The application of the potential to the driving electrode 72A can be realized through the portion 31g in the outer frame 30. The application of the potential to the driving electrode 72B can be realized through the portion 31h in the outer frame 30. In the present embodiment, for example, the drive electrodes 71A and 71B are connected to the ground, and then the application of the predetermined potential to the drive electrode 72A and the application of the predetermined potential to the drive electrode 72B are alternately repeated. The part can be swung.

For example, when a predetermined angular velocity or acceleration is applied to the sensing device Y or the movable part in a state where the movable part is swung or vibrated as described above, the land part 10 includes the detection electrode 61 and the axis A1. The gap volume between the portion of the detection electrode 61 facing the detection electrode 62A and the detection electrode 62A changes, and the detection electrode 61 faces the detection electrode 62B. The void volume between the part and the detection electrode 62B changes (the detection electrode 61 and the detection electrodes 62A and 62B can be relatively moved toward and away from each other). When these void volumes change, the capacitance between the detection electrodes 61 and 62A and the capacitance between the detection electrodes 61 and 62B change. The rotational displacement amount of the land portion 10 and the detection electrode 61 can be detected based on the change in capacitance between the detection electrodes 61 and 62A and the change in capacitance between the detection electrodes 61 and 62B. it can. Based on the detection result, the angular velocity and acceleration acting on the sensing device Y or the movable part can be calculated.

9 to 13 show a method for manufacturing the packaged device X1 by the micromachining technology. 9 to 12 show changes in the cross section corresponding to FIG. 5 included in a single device formation section. FIG. 13 represents a partial cross section across a plurality of device forming sections.

In manufacturing the packaged device X1, first, a device wafer 100 as shown in FIG. 9A is prepared. The device wafer 100 is an SOI wafer having a laminated structure including silicon layers 101 and 102 and an insulating layer 103 between the silicon layers 101 and 102, and a plurality of devices on which a sensing device Y is formed. Includes forming compartment. The silicon layer 101 has a first surface 101 'and the silicon layer 102 has a second surface 102'. The silicon layers 101 and 102 are made of a silicon material imparted with conductivity by doping impurities. As the impurities, p-type impurities such as B and n-type impurities such as P and Sb can be employed. The insulating layer 103 is made of, for example, silicon oxide. The thickness of the silicon layer 101 is, for example, 10 to 100 μm, the thickness of the silicon layer 102 is, for example, 100 to 500 μm, and the thickness of the insulating layer 103 is, for example, 1 to 2 μm.

Next, as shown in FIG. 9B, a through hole 101a penetrating the silicon layer 101 and the insulating layer 103 is formed. Specifically, first, after a resist pattern (not shown) having a predetermined opening is formed on the silicon layer 101, the insulating layer is formed by DRIE (Deep Reactive Ion Etching) using the resist pattern as a mask. An anisotropic dry etching process is performed on the silicon layer 101 until 103 is partially exposed. In DRIE, good anisotropic dry etching can be performed in a Bosch process in which etching and sidewall protection are alternately performed. Such a Bosch process can be adopted for this step and the subsequent DRIE. Thereafter, the exposed portion of the insulating layer 103 is removed by another etching method (for example, a wet etching method using buffered hydrofluoric acid [BHF] made of hydrofluoric acid and ammonium fluoride). In this way, the through hole 101a can be formed.

Next, as shown in FIG. 9C, the conductive plug 11 is formed. Specifically, the conductive plug 11 can be formed by filling the through hole 101a with a conductive material.

Next, as shown in FIG. 9D, an oxide film pattern 104 is formed on the silicon layer 101, and an oxide film pattern 105 is formed on the silicon layer 102. A resist pattern (not shown) is also formed on the silicon layer 101. The resist pattern has a pattern shape corresponding to the driving electrode 71A (electrode tooth 71a) and the driving electrode 71B (electrode tooth 71b) to be formed in the silicon layer 101. The oxide film pattern 104 has a pattern shape corresponding to a portion other than the driving electrodes 71A and 71B to be formed in the silicon layer 101. The oxide film pattern 105 has a pattern shape corresponding to a portion to be formed in the silicon layer 102.

In forming the oxide film pattern 104, first, for example, a silicon oxide film is formed on the surface of the silicon layer 101 by a CVD method until the thickness becomes, for example, 1 μm. Next, the oxide film on the silicon layer 101 is patterned by etching using a predetermined resist pattern as a mask. The oxide film pattern 105 can also be formed on the silicon layer 102 through formation of an oxide material, formation of a resist pattern on the oxide film, and subsequent etching treatment. On the other hand, in forming the resist pattern, first, a predetermined liquid photoresist is formed on the silicon layer 101 by spin coating. Next, the photoresist film is patterned through an exposure process and a subsequent development process.

Next, as shown in FIG. 10A, using the oxide film pattern 104 and a resist pattern outside the figure as a mask, the silicon layer 101 is formed to a depth in the thickness direction of the silicon layer 101 by DRIE. Etching is performed on the surface. The depth substantially corresponds to the height of the drive electrodes 71A and 71B.

Next, after removing the resist pattern (not shown), the silicon layer 101 is etched by DRIE using the oxide film pattern 104 as a mask as shown in FIG. In this step, the land portion 10 to be formed in the silicon layer 101, a part of the inner frame 20, a part of the outer frame 30, the connecting portions 40 and 50, the detection electrodes 62A and 62B, and the driving electrode 71A, 71B, 72A and 72B are formed. After this step, the oxide film pattern 104 is removed.

Next, as shown in FIG. 10C, the packaging wafer 201 is bonded to the silicon layer 101 side of the device wafer 100 (first bonding step). The packaging wafer 201 includes a plurality of packaging member forming sections in which the packaging member 80 is formed, and has a recess 80a for each section.

FIG. 14 shows a method for manufacturing the packaging wafer 201 as a change in cross section corresponding to the cross section of the packaging wafer 201 shown in FIG.

In manufacturing the packaging wafer 201, first, as shown in FIG. 14A, oxide film patterns 202 and 203 are formed on the wafer 201 '. Wafer 201 'is a silicon wafer. The thickness of the wafer 201 'is, for example, 200 to 500 μm. The oxide film patterns 202 and 203 are made of, for example, silicon oxide. The thicknesses of the oxide film patterns 202 and 203 are, for example, 0.1 to 2 μm. Such oxide film patterns 202 and 203 can be formed, for example, by forming an oxide film on the surface of the wafer 201 'by a thermal oxidation method and then patterning the oxide film.

Next, as shown in FIG. 14B, a recess 80a is formed in the wafer 201 '. By using the resist pattern (not shown) used for patterning the oxide film pattern 203 as a mask, the recesses 80a can be formed by performing a dry etching process on the wafer 201 '.

Next, as shown in FIG. 14C, a resist pattern 204 is formed on the wafer 201 ′ so as to cover the oxide film pattern 202. The resist pattern 204 has an opening 204a.

Next, as shown in FIG. 14D, a recess 82a 'is formed. Specifically, using the resist pattern 204 as a mask, the wafer 201 ′ is etched to a depth in the middle of the wafer 201 ′ by DRIE. Thereafter, the resist pattern 204 is removed using, for example, a stripping solution.

In the bonding step shown in FIG. 10C, the first surface 101 ′ of the silicon layer 101 of the device wafer 100, while aligning the packaging wafer 201 formed as described above and the device wafer 100, The oxide film pattern 203 (insulating film) on the packaging wafer 201 is bonded. At this time, in order to perform accurate alignment, the recesses 82a ′ already formed on the packaging wafer 201 and the terminal portions (portions 31a to 31h) already formed on the device wafer 100 are aligned. . This bonding process is performed by, for example, a room temperature bonding method. The room temperature bonding method is a state in which impurities on the surfaces to be bonded are removed by etching with an Ar beam or the like in a high vacuum to clean the bonding surfaces (in a state where dangling bonds of constituent atoms are exposed). It is a method of sticking together.

In manufacturing the packaged device X1, next, as shown in FIG. 10D, the silicon layer 102 is etched by DRIE using the oxide film pattern 105 as a mask. In this step, a part of the inner frame 20 to be formed in the silicon layer 102, a part of the outer frame 30, and the detection electrode 61 are formed.

Next, as shown in FIG. 11A, the exposed portions of the insulating layer 103 and the oxide film pattern 105 are removed by etching. As an etching method, dry etching or wet etching can be employed. When dry etching is employed, for example, HF gas can be employed as the etching gas. When employing wet etching, for example, BHF can be used as the etchant.

Next, as shown in FIG. 11B, the packaging wafer 205 is bonded to the silicon layer 102 side of the device wafer 100 (second bonding step). As a joining method, for example, a room temperature joining method can be employed. For example, when the second bonding step is performed by a room temperature bonding method, the inside of the package is vacuum-sealed. The packaging wafer 205 includes a plurality of packaging member forming sections in which the packaging member 90 is formed, and has a recess 90a in each section (the recess 90a is, for example, an unprocessed packaging wafer). After forming a predetermined oxide film pattern on 205, it can be formed by etching the packaging wafer 205 using the oxide film pattern as a mask. Through this step, packaging at the wafer level is achieved.

Next, as shown in FIG. 11C, the packaging wafer 205 is thinned, for example, by performing DRIE or polishing treatment.

Next, as shown in FIG. 12A, using the oxide film pattern 202 as a mask, the packaging wafer 201 thru | or the depth to the middle of the thickness direction of the packaging wafer 201 thru | or wafer 201 'by DRIE. Etching is performed on the wafer 201 '. As a result, a region of the wafer 201 ′ that is not covered with the oxide film pattern 202 is thinned. At this time, the recess 82 a ′ extends downward in the drawing within the packaging wafer 201. Thereafter, the oxide film pattern 202 is removed.

Next, as shown in FIG. 12B, the packaging wafer 201 or the wafer 201 'is etched by DRIE. In this step, the region covered with the oxide film pattern 202 on the wafer 201 ′ is thinned, and the region not covered with the oxide film pattern 202 on the wafer 201 ′ is further thinned. A first portion 81 and a thin second portion 82 at 80 are formed. Further, the recess 82 a ′ penetrates the wafer 201 ′ and reaches the oxide film pattern 203.

Next, as shown in FIG. 12C, the portion of the oxide film pattern 203 that faces the recess 82a 'is removed by etching. In this step, the through hole 82a in each packaging member 80 is formed.

Next, as shown in FIGS. 13 (a) and 13 (b), the laminated structure including the device wafer 100 and the packaging wafers 201 and 205 is cut (dicing step). As described above, the packaged device X1 according to the first embodiment of the present invention can be manufactured.

According to this method, since packaging at the wafer level can be achieved, it is possible to suppress the deterioration of the operation performance of the movable part due to the adhesion and damage of each part of the sensing device Y which is a micro movable element. it can.

The packaging wafer 201 in the present method includes a plurality of sections for forming the packaging member 80 in the packaged device X1 to be manufactured, and the packaging wafer 201 to the wafer used in the first bonding step described above is used. The thickness of 201 ′ is not the same as the thickness of the packaging member 80, and the packaging wafer 201 to the wafer 201 ′ that are thicker than the packaging member 80 are used for the first bonding step. After wafer level packaging is achieved (after both the first and second bonding steps are completed), the packaging wafer 201 that is bonded to the device wafer 100 and is less likely to be damaged is processed. As a result, the packaging wafer 201 is thinned to a desired level (from the process described above with reference to FIG. 12A to the process described above with reference to FIG. 12C). The first packaging wafer processing step in FIG. The packaging member 80 is derived from the thinned packaging wafer 201 in this way. As described above, the present method can easily reduce the thickness of the packaging member 80, and is therefore suitable for reducing the thickness of the manufactured packaged device X1 or package.

Also, the packaging wafer 201 provided for the first bonding step in this method is not easily damaged and is easy to handle. This is because the packaging wafer 201 provided for the first bonding step in this method is not formed with an opening that penetrates the wafer. The through holes 82a to be formed in the packaging member 80 in order to expose the portions 31a to 31h as the terminal portions of the sensing device Y to the outside of the package are formed after the wafer level packaging is achieved (first and second bonding steps). Are formed on the packaging wafer 201 which is bonded to the device wafer 100 and is less likely to be damaged.

As described above, this method is suitable for reducing the thickness of the resulting package while ensuring the strength or ease of handling of the packaging wafer 201 before being bonded to the device wafer 100.

In addition, in the packaging member 80 of the packaged device X1 manufactured by the present method, the through hole 82a is provided in the second portion 82 that is thinner than the first portion 81. It is suitable for wire bonding to the terminal portions (portions 31a to 31h) partially exposed at each through hole 82a.

In the packaged device X1 manufactured by this method, the packaging member 80 is bonded to the sensing device Y via the oxide film pattern 203 (insulating film). The sensing device Y and the packaging member 80 are electrically separated by the oxide film pattern 203, so that it is possible to prevent each part of the sensing device Y from being illegally electrically connected via the packaging member 80. .

In the packaged device X1, the sensing device Y and the packaging member 90 may be joined via an insulating film such as an oxide film. In this case, it is avoided that the sensing device Y and the packaging member 90 are electrically separated by the insulating film, and that each part of the sensing device Y is illegally electrically connected via the packaging member 90. Can do.

Further, at least the opening end of each through hole 82a of the packaging member 80 in the packaged device X1 may have a shape that widens as the distance from the sensing device Y increases. In such a configuration, it is easy to wire bond to the terminal portions (portions 31a to 31h) that are partially exposed in the respective through holes 82a.

15 to 22 show a packaged device X2 according to the second embodiment of the present invention. FIG. 15 is a partially omitted plan view of the packaged device X2, and FIG. 16 is another partially omitted plan view of the packaged device X2. 17 to 22 are cross-sectional views taken along line XVII-XVII, line XVIII-XVIII, line XIX-XIX, line XX-XX, line XXI-XIXI, and line XXII-XXII in FIG. 15, respectively.

The packaged device X2 includes a sensing device Y, a packaging member 85 (omitted in FIG. 15), and a packaging member 90 (omitted in FIG. 16), and includes a packaging member 85 instead of the packaging member 80. This is different from the packaged device X1 described above.

The packaging member 85 is joined to the first layer portion 31 side of the outer frame 30 of the sensing device Y as shown in FIG. 17, for example, and has a recess 85 a at a location corresponding to the movable portion of the sensing device Y. The packaging member 85 has a plurality of through holes 85b. The depth of the through hole 85a is, for example, 50 to 100 μm, and the diameter of the through hole 85a is, for example, 50 to 100 μm. Each of the portions 31a to 31h, which are terminal portions for external connection in the sensing device Y, partially faces the through hole 85b. That is, all of the portions 31a to 31h serving as terminal portions are partially exposed outside the package through the through holes 85b.

The configuration of the sensing device Y of the packaged device X2 and the configuration of the packaging member 90 are the same as the configuration of the sensing device Y of the packaged device X1 and the configuration of the packaging member 90.

The packaged device X2 having the above configuration can be connected to an external circuit by wire bonding. Specifically, the terminal portions (portions 31a to 31h) exposed in the through holes 85b of the packaging member 85 and predetermined terminal portions of the external circuit can be electrically connected by wire bonding. The packaged device X2 can be driven in the same manner as the packaged device X1.

23 to 27 show a method for manufacturing the packaged device X2 by the micromachining technology. FIG. 23 to FIG. 26 show changes in cross section corresponding to FIG. 19 included in a single device forming section. FIG. 27 represents a partial cross section across multiple device forming sections.

In the manufacture of the packaged device X2, first, a device wafer 100 as shown in FIG. Next, as shown in FIG. 23B, a through hole 101a penetrating the silicon layer 101 and the insulating layer 103 is formed. Next, as shown in FIG. 23C, the conductive plug 11 is formed. Next, as shown in FIG. 23D, an oxide film pattern 104 is formed on the silicon layer 101, and an oxide film pattern 105 is formed on the silicon layer 102. A resist pattern (not shown) is also formed on the silicon layer 101. Next, as shown in FIG. 24A, using the oxide film pattern 104 and a resist pattern outside the figure as a mask, the silicon layer 101 is formed to a depth in the middle of the silicon layer 101 by DRIE. Etching is performed on the surface. Next, after removing the resist pattern (not shown), the silicon layer 101 is etched by DRIE using the oxide film pattern 104 as a mask, as shown in FIG. In this step, the land portion 10 to be formed in the silicon layer 101, a part of the inner frame 20, a part of the outer frame 30, the connecting portions 40 and 50, the detection electrodes 62A and 62B, and the driving electrode 71A, 71B, 72A and 72B are formed. The process from FIG. 23A to FIG. 24B is the same as the process described above with reference to FIG. 9A to FIG. 10B for the method of manufacturing the packaged device X1.

In the manufacture of the packaged device X2, next, as shown in FIG. 24C, the packaging wafer 206 is bonded to the silicon layer 101 side of the device wafer 100 (first bonding step). The packaging wafer 206 includes a plurality of packaging member forming sections in which the packaging member 85 is formed, and has a recess 85a for each section.

FIG. 28 shows a manufacturing method of the packaging wafer 206 as a change in cross section corresponding to the cross section of the packaging wafer 206 shown in FIG.

In manufacturing the packaging wafer 206, first, as shown in FIG. 28A, a resist pattern 207 and an oxide film pattern 208 are formed on the wafer 206 '. Wafer 206 'is a silicon wafer. The thickness of the wafer 206 'is, for example, 200 to 500 μm. The resist pattern 207 has an opening 207a. The oxide film pattern 208 is made of, for example, silicon oxide. The thickness of the oxide film pattern 208 is, for example, 0.1 to 2 μm. Such an oxide film pattern 208 can be formed, for example, by forming an oxide film on the surface of the wafer 206 ′ by a thermal oxidation method and then patterning the oxide film.

Next, as shown in FIG. 28B, a recess 85a is formed in the wafer 206 '. By using the resist pattern (not shown) used for patterning the oxide film pattern 208 as a mask, the wafer 206 ′ is subjected to a dry etching process, whereby the recess 85 a can be formed.

Next, as shown in FIG. 28 (c), a recess 85b 'is formed. Specifically, using the resist pattern 207 as a mask, the wafer 206 'is etched by DRIE to a depth in the middle of the wafer 206' in the thickness direction. Thereafter, the resist pattern 207 is removed using, for example, a stripping solution.

In the bonding step shown in FIG. 24C, the first surface 101 ′ of the silicon layer 101 of the device wafer 100 and the package are aligned while aligning the device wafer 100 and the packaging wafer 206 formed as described above. The oxide film pattern 208 (insulating film) on the bonding wafer 206 is bonded. At this time, in order to perform accurate alignment, the recesses 85b ′ already formed on the packaging wafer 206 and the terminal portions (portions 31a to 31h) already formed on the device wafer 100 are aligned. . This bonding process is performed by, for example, a room temperature bonding method.

In manufacturing the packaged device X2, next, as shown in FIG. 24D, the silicon layer 102 is etched by DRIE using the oxide film pattern 105 as a mask. In this step, a part of the inner frame 20 to be formed in the silicon layer 102, a part of the outer frame 30, and the detection electrode 61 are formed.

Next, as shown in FIG. 25A, the exposed portions of the insulating layer 103 and the oxide film pattern 105 are removed by etching. Next, as shown in FIG. 25B, the packaging wafer 205 is bonded to the silicon layer 102 side of the device wafer 100 (second bonding step). For example, when the second bonding step is performed by a room temperature bonding method, the inside of the package is vacuum-sealed. Next, as shown in FIG. 25C, the packaging wafer 205 is thinned, for example, by performing DRIE or polishing treatment. The process from FIG. 25A to FIG. 25C is the same as the process described above with reference to FIG. 11A to FIG. 11C for the method of manufacturing the packaged device X1.

Next, as shown in FIG. 26A, the packaging wafer 206 or wafer 206 'is etched by DRIE to thin the packaging wafer 206. Next, as shown in FIG. In this step, the recess 85 b ′ penetrates the wafer 206 ′ and reaches the oxide film pattern 208.

Next, as shown in FIG. 26B, the portion of the oxide film pattern 208 facing the recess 85b 'is removed by etching. In this step, the through hole 85b in each packaging member 85 is formed.

Next, as shown in FIGS. 27 (a) and 27 (b), the laminated structure including the device wafer 100 and the packaging wafers 205 and 206 is cut (dicing step). As described above, the packaged device X2 according to the second embodiment of the present invention can be manufactured.

According to this method, since packaging at the wafer level can be achieved, it is possible to suppress the deterioration of the operation performance of the movable part due to the adhesion and damage of each part of the sensing device Y which is a micro movable element. it can.

The packaging wafer 206 in the present method includes a plurality of sections for forming the packaging member 85 in the packaged device X2 to be manufactured. The packaging wafer 206 or wafer used in the first bonding step described above is used. The thickness of 206 ′ is not the same as the thickness of the packaging member 85, and a packaging wafer 206 to wafer 206 ′ thicker than the packaging member 85 is subjected to the first bonding process. After the wafer level packaging is achieved (after both the first and second bonding steps are completed), the packaging wafer 206 that is bonded to the device wafer 100 and is not easily damaged is processed. As a result, the packaging wafer 206 is thinned to a desired degree (the process described above with reference to FIG. 26A and the process described above with reference to FIG. Constitutes a first packaging wafer processing step). The packaging member 85 is derived from the thinned packaging wafer 206 in this way. As described above, the present method easily reduces the thickness of the packaging member 85 and is therefore suitable for reducing the thickness of the manufactured packaged device X2 or package.

Further, the packaging wafer 206 subjected to the first bonding step in this method is not easily damaged and is easy to handle. This is because the packaging wafer 206 subjected to the first bonding step in the present method is not formed with an opening that penetrates the wafer. The through holes 85b to be formed in the packaging member 85 in order to expose the portions 31a to 31h as the terminal portions of the sensing device Y to the outside of the package are formed after the wafer level packaging is achieved (first and second bonding steps). Are formed on the packaging wafer 206 that is bonded to the device wafer 100 and is less likely to be damaged.

As described above, this method is suitable for reducing the thickness of the resulting package while ensuring the strength or ease of handling of the packaging wafer 206 before being bonded to the device wafer 100.

In the packaged device X2 manufactured by this method, the packaging member 85 is bonded to the sensing device Y via the oxide film pattern 208 (insulating film). The sensing device Y and the packaging member 85 are electrically separated by the oxide film pattern 208, and it is possible to prevent each part of the sensing device Y from being illegally electrically connected via the packaging member 85. .

In the packaged device X2, the sensing device Y and the packaging member 90 may be joined via an insulating film such as an oxide film. In this case, it is avoided that the sensing device Y and the packaging member 90 are electrically separated by the insulating film, and that each part of the sensing device Y is illegally electrically connected via the packaging member 90. Can do.

In addition, at least the opening end of each through hole 85b of the packaging member 85 in the packaged device X2 may have a shape that widens as the distance from the sensing device Y increases. In such a configuration, it is easy to wire bond to the terminal portions (portions 31a to 31h) that are partially exposed in the respective through holes 85b.

Claims (19)

A micro movable element having a movable part and a terminal part, a first packaging member having a through hole at a position corresponding to the terminal part and joined to the micro movable element, and the first packaging member being opposite to each other And a second packaging member joined to the micro movable element on the side of the package, the method for manufacturing a packaged micro movable element,
A device wafer having a first surface and a second surface opposite to the first surface and including a plurality of micro movable element forming sections for forming the micro movable element, on the first surface side, the first surface side A first bonding step of bonding a first packaging wafer including a plurality of first packaging member forming sections for forming one packaging member;
A second bonding step of bonding a second packaging wafer including a plurality of second packaging member forming sections for forming the second packaging member to the second surface side of the device wafer;
In each first packaging member forming section, a first packaging wafer processing step of forming the through hole and thinning the first packaging wafer;
A dicing step of cutting a laminated structure including the device wafer, the first packaging wafer, and the second packaging wafer. 2. The packaged micro movable device manufacturing method according to claim 1, wherein a recess is formed at a through hole forming portion in each first packaging member forming section of the first packaging wafer before the first bonding step. The first packaging member forming section includes a first region and a second region including the through hole forming portion and its periphery, and the first packaging wafer processing step is different from the second region. A first step of forming the through-hole while thinning the second region by performing an isotropic etching process; and a second step of thinning the first region while further thinning the second region. The packaged micro movable device manufacturing method according to claim 2. 3. The packaged micro movable device manufacturing method according to claim 2, wherein, in the first packaging wafer processing step, the through hole is formed while the first packaging wafer is thinned. The recessed part which will be opposed to the said movable part of the said micro movable element is formed in each 1st packaging member formation division of the said 1st packaging wafer before the said 1st joining process. Packaged micro movable element manufacturing method. The recessed part which will be opposed to the said movable part of the said micro movable element is formed in each 2nd packaging member formation division of the said 2nd packaging wafer before the said 2nd joining process. Packaged micro movable element manufacturing method. 2. The packaged micro movable device manufacturing method according to claim 1, wherein in the first packaging wafer processing step, at least an opening end of the through hole is formed in a shape that widens as the distance from the micro movable device increases. The packaged micro movable device manufacturing method according to claim 1, wherein, in the first bonding step, the device wafer and the first packaging wafer are bonded via an insulating film. The packaged micro movable element manufacturing method according to claim 1, wherein, in the second bonding step, the device wafer and the second packaging wafer are bonded via an insulating film. The device wafer has a laminated structure including a first layer having the first surface, a second layer having the second surface, and an intermediate layer between the first and second layers. The packaged micro movable device manufacturing method according to claim 1, wherein a processing step of performing an etching process on the first layer using a mask pattern provided on the first surface as a mask is performed before one bonding step. Method. After the first bonding step and before the second bonding step, a processing step of performing an etching process on the second layer using a mask pattern provided on the second surface as a mask is performed. The packaged micro movable device manufacturing method according to claim 10. A micro movable element having a movable part and a terminal part, a first packaging member having a through hole at a position corresponding to the terminal part and joined to the micro movable element, and the first packaging member being opposite to each other And a second packaging member joined to the micro movable element on the side of the packaged micro movable element. The packaged micro movable element according to claim 12, wherein the first packaging member includes a first portion and a second portion that is thinner than the first portion, including a portion where the through hole is formed and the periphery thereof. . The packaged micro movable device according to claim 12, wherein the first packaging member has a recess at a location facing the movable portion of the micro movable device. The packaged micro movable device according to claim 12, wherein the second packaging member has a recess at a location facing the movable portion of the micro movable device. The packaged micro movable element according to claim 12, wherein at least an open end of the through hole has a shape that widens as the distance from the micro movable element increases. The packaged micro movable device according to claim 12, wherein an insulating film is interposed between the micro movable device and the first packaging member and / or between the micro movable device and the second packaging member. element. 13. The micro movable element according to claim 12, further comprising a fixed portion and a connecting portion for connecting the fixed portion and the movable portion in addition to the movable portion, wherein the movable portion is swingable. Packaged micro movable element. The packaged micro movable element according to claim 18, wherein the micro movable element is an angular velocity sensor or an acceleration sensor.

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