JP2012122838A - Mems element and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a MEMS element capable of reducing an element area and also reducing manufacturing costs.SOLUTION: A MEMS element includes a semiconductor substrate 20; a movable part 33 provided on a principal surface 20a of the semiconductor substrate 20 so as to be displaceable relative to the semiconductor substrate 20; a lid part 50 provided on the principal surface 20a of the semiconductor substrate 20 so as to cover the movable part 33; a first electrode terminal 41 provided in an area that is on the principal surface 20a of the semiconductor substrate 20 and outside the lid part 50; and first wiring 51 which is formed on a surface that is a part of the lid part 50 and faces the semiconductor substrate 20 and which electrically connects the first electrode terminal 41 to the movable part 33.

Description

  The present invention relates to a MEMS element and a method for manufacturing a MEMS element.

  For example, a MEMS element having functions such as an acceleration sensor, a vibrator, and a mechanical filter has been developed.

Some MEMS elements are formed on a semiconductor substrate made of, for example, an SOI substrate. In an SOI substrate, an insulating layer is formed on a supporting substrate, and a conductor layer (active layer) is formed on the insulating layer. The support substrate is made of Si, for example, and the insulating layer is made of SiO ₂ , for example. Furthermore, the conductor layer formed on the insulating layer is made of, for example, conductive silicon.

  As a MEMS element formed on a semiconductor substrate made of such an SOI substrate, a semiconductor substrate, a pedestal support portion, a beam, a movable portion, a terminal portion, a wiring portion, a pedestal portion, and a cap are provided. An example of a MEMS element is disclosed (for example, see Patent Document 1). The pedestal support is fixed to the semiconductor substrate and formed so as to surround a predetermined region. The beam is connected to the semiconductor substrate and formed in a predetermined region. The movable part is connected to the beam and is suspended in a space within a predetermined area. The terminal portion is formed outside a predetermined region surrounded by the pedestal support portion. The wiring part connects the movable part and the terminal part through the base support part. The pedestal portion is formed on the pedestal support portion and the wiring portion, and is formed so as to surround a predetermined region.

JP 2008-046078 A

  However, the above MEMS element has the following problems.

  The MEMS element is made of aluminum (Al) and polysilicon (Si), and wiring for electrically connecting the terminal portion and the movable portion is formed. For example, the wiring may be formed on a main body element including a beam to which a movable part is connected.

  However, the pattern of the movable part may become complicated, for example, the number of movable parts increases as the acceleration sensor functions become higher. Therefore, for example, another movable part may be formed between the terminal part and one movable part. In such an arrangement, when wiring is formed on the main body element, it is necessary to arrange the wiring that connects the terminal portion and one movable portion so as to avoid other movable portions, so the wiring pattern is complicated. In addition, there is a problem that the area of the MEMS element increases.

  In order to easily arrange wiring so as to avoid other movable parts, an opening is formed in the lid (cap), a through electrode electrically connected to the movable part is provided in the opening, and the lid It is conceivable to form a wiring for electrically connecting the through electrode and the terminal part on the upper surface of the part. However, there is a problem in that the manufacturing cost increases because the step of forming the opening in the lid and providing the through electrode in the opening is included.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a MEMS element that can reduce the element area and reduce the manufacturing cost.

  In order to solve the above-described problems, the present invention is characterized by the following measures.

  A MEMS element according to a first aspect of the present invention is a semiconductor substrate, a movable portion provided on the main surface of the semiconductor substrate so as to be relatively displaceable with respect to the semiconductor substrate, and on the main surface of the semiconductor substrate, A lid provided to cover the movable part; a first electrode terminal provided in a region outside the lid on the main surface of the semiconductor substrate; and the semiconductor substrate of the lid It is formed in the surface which opposes, and has the 1st wiring which electrically connects the 1st electrode terminal and the movable part.

  According to a second invention, in the MEMS element according to the first invention, the lid portion has a recess formed in a surface facing the semiconductor substrate, and the first wiring is formed in the recess. Yes.

  According to a third aspect of the present invention, in the MEMS element according to the second aspect, the concave portion has an opening diameter that decreases in the depth direction.

  According to a fourth invention, in the MEMS element according to any one of the first to third inventions, the lid portion is bonded to the semiconductor substrate by thermocompression bonding, solder bonding, or eutectic bonding. .

  According to a fifth invention, in the MEMS element according to any one of the first to fourth inventions, a fixing portion provided on the main surface of the semiconductor substrate, fixed to the semiconductor substrate, and the semiconductor A second electrode terminal provided on the main surface of the substrate and in a region outside the lid portion, and a surface of the lid portion facing the semiconductor substrate, the second electrode terminal And a second wiring for electrically connecting the fixed portion, and the lid portion is provided on the main surface of the semiconductor substrate so as to cover the movable portion and the fixed portion. Yes.

  According to a sixth aspect of the present invention, there is provided a method of manufacturing a MEMS element comprising: a movable portion forming step of forming a movable portion that can be displaced relative to the semiconductor substrate on the main surface of the semiconductor substrate; and the main surface of the semiconductor substrate. An electrode terminal forming step of forming a first electrode terminal outside a region where the lid portion is provided, and electrically connecting the first electrode terminal and the movable portion to one surface of the lid portion A wiring forming step for forming a first wiring for the first wiring, and the lid portion on which the first wiring is formed, with the one surface of the lid portion facing the main surface of the semiconductor substrate. A cover step covering the movable portion, and a bonding step of bonding to the semiconductor substrate so that the first electrode terminal and the movable portion are electrically connected via the first wiring. .

  7th invention has the recessed part formation process which forms a recessed part in the said one surface of the said cover part in the manufacturing method of the MEMS element which concerns on 6th invention, The said wiring formation process includes the said recessed part in the said recessed part The first wiring is formed.

  According to an eighth aspect of the present invention, in the method of manufacturing a MEMS element according to the seventh aspect, the recess forming step is performed by etching the one surface of the lid made of a silicon substrate with an alkaline etching solution. The recess is formed so that the thickness decreases in the depth direction.

  According to a ninth aspect of the present invention, in the method for manufacturing a MEMS element according to any one of the sixth to eighth aspects, the bonding step includes the step of bonding the lid portion to the semiconductor by thermocompression bonding, solder bonding, or eutectic bonding. It is bonded to the substrate.

  According to a tenth aspect of the present invention, in the method for manufacturing a MEMS element according to any one of the sixth to ninth aspects, the movable part forming step includes the semiconductor part together with the movable part on the main surface of the semiconductor substrate. The electrode terminal forming step forms a second electrode terminal together with the first electrode terminal outside the region where the lid portion is provided. The wiring formation step forms, on the one surface of the lid portion, a second wiring for electrically connecting the second electrode terminal and the fixing portion together with the first wiring. In the bonding step, the lid portion in which the first wiring and the second wiring are formed is in a state where the one surface of the lid portion faces the main surface of the semiconductor substrate. When the lid part covers the movable part and the fixed part, In addition, the first electrode terminal and the movable part are electrically connected via the first wiring, and the second electrode terminal and the fixed part are electrically connected via the second wiring. It is bonded to the semiconductor substrate so as to be connected to the semiconductor substrate.

  According to the present invention, the element area can be reduced and the manufacturing cost can be reduced.

It is a top view which shows typically the structure of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 1) which shows typically the structure of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 2) which shows typically the structure of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 3) which shows typically the structure of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 4) which shows typically the structure of the MEMS element which concerns on the 1st Embodiment of this invention. It is a top view showing typically the state where the MEMS element concerning a 1st embodiment of the present invention is operating as an acceleration sensor. It is sectional drawing (the 1) which shows typically the manufacturing method of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 2) which shows typically the manufacturing method of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 3) which shows typically the manufacturing method of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 4) which shows typically the manufacturing method of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 5) which shows typically the manufacturing method of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 6) which shows typically the manufacturing method of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 7) which shows typically the manufacturing method of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 8) which shows typically the manufacturing method of the MEMS element which concerns on the 1st Embodiment of this invention. It is sectional drawing (the 9) which shows typically the manufacturing method of the MEMS element which concerns on the 1st Embodiment of this invention. 6 is a plan view schematically showing a configuration of a MEMS element according to Comparative Example 1. FIG. 6 is a cross-sectional view schematically showing a configuration of a MEMS element according to Comparative Example 1. FIG. 6 is a cross-sectional view schematically showing a configuration of a MEMS element according to Comparative Example 2. FIG. It is a top view which shows typically the structure of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 1) which shows typically the structure of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 2) which shows typically the structure of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 3) which shows typically the structure of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 4) which shows typically the structure of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 1) which shows typically the manufacturing method of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 2) which shows typically the manufacturing method of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 3) which shows typically the manufacturing method of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 4) which shows typically the manufacturing method of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 5) which shows typically the manufacturing method of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 6) which shows typically the manufacturing method of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 7) which shows typically the manufacturing method of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 8) which shows typically the manufacturing method of the MEMS element which concerns on the 2nd Embodiment of this invention. It is sectional drawing (the 9) which shows typically the manufacturing method of the MEMS element which concerns on the 2nd Embodiment of this invention.

Next, a mode for carrying out the present invention will be described with reference to the drawings. In the following, in order to facilitate the illustration, even the plan view may be hatched in the same manner as the cross-sectional view.
(First embodiment)
First, a micro electro mechanical system element (hereinafter referred to as “MEMS element”) and a method for manufacturing the MEMS element according to the first embodiment of the present invention will be described.

  First, the MEMS element according to the present embodiment will be described with reference to FIGS.

  FIG. 1 is a plan view schematically showing the configuration of the MEMS element according to the present embodiment.

  The MEMS element 10 includes a semiconductor substrate 20, a support portion 30, a first beam portion 31, a second beam portion 32, a movable portion 33, a fixed portion 34, a first electrode terminal 41, a second electrode terminal 42, a lid. The unit 50 includes a first wiring 51 and a second wiring 52. A region on the main surface 20a of the semiconductor substrate 20 where the first beam portion 31, the second beam portion 32, the movable portion 33, and the fixed portion 34 are formed is referred to as an element formation region DA. A portion formed in the element formation area DA corresponds to a main body element.

  In FIG. 1, the lid 50, the first wiring 51, and the second wiring 52 are not shown for ease of illustration. However, in FIG. 1, the area | region where the cover part 50 is provided on the main surface 20a of the semiconductor substrate 20 is shown by the area | region I enclosed with the dotted line. The region of the lid 50 where the first wiring 51 is formed is indicated by a region II surrounded by a dotted line, and the region of the lid 50 where the second wiring 52 is formed is surrounded by a dotted line. This is indicated by region III.

  The support portion 30 is the main surface 20a of the semiconductor substrate 20 and is formed so as to surround the element formation region DA.

  The first beam portion 31 and the second beam portion 32 are formed in the element formation region DA. The first beam portion 31 and the second beam portion 32 are fixed to the lower semiconductor substrate 20. As shown in FIG. 1, the first beam portion 31 may not be directly connected to the side of the support portion 30 where a first electrode terminal 41 described later is formed, and the second beam portion 32 is In addition, it is not necessary to be directly connected to the side where the second electrode terminal 42 described later of the support portion 30 is formed.

  A plurality of movable portions 33 are provided in the element formation area DA, and the plurality of movable portions 33 are connected to the first beam portion 31. The movable portion 33 is provided so as to be capable of relative displacement with respect to the semiconductor substrate 20, and functions as a mass portion of an acceleration sensor, for example.

  A plurality of fixing portions 34 are provided in the element forming area DA, and the plurality of fixing portions 34 are connected to the second beam portion 32. The fixing part 34 is fixed to the semiconductor substrate 20. The plurality of movable portions 33 and fixed portions 34 are alternately arranged, and adjacent fixed portions 34 are provided so as to sandwich the movable portion 33. The movable part 33 and the fixed part 34 constitute a capacitive element, and when the movable part 33 is displaced in the Y direction, the capacitance between the movable part 33 and the fixed part 34 changes, so that the Y direction. It is comprised so that the acceleration of can be detected.

  A movable portion side electrode 35 is formed on the upper surface of the support portion 30 to which the first beam portion 31 is connected, and is fixed to the upper surface of the support portion 30 to which the second beam portion 32 is connected. A side electrode 36 is formed. The movable part side electrode 35 is electrically connected to a first wiring 51 described later, and the fixed part side electrode 36 is electrically connected to a second wiring 52 described later. The movable portion side electrode 35 may be formed on the upper surface of the first beam portion 31 and the upper surface of the movable portion 33, and the fixed portion side electrode 36 is formed on the upper surface of the second beam portion 32 and the fixed portion 34. It may also be formed on the upper surface.

  Wiring portions 43 and 44 are formed on the upper surface of the support portion 30 so as to extend from the element formation region DA to a region outside the region I. The wiring part 43 is electrically connected to a first wiring 51 described later, and the wiring part 44 is electrically connected to a second wiring 52 described later.

  The first electrode terminal 41 is formed on the main surface 20 a of the semiconductor substrate 20 and in a region outside the region I where the lid portion 50 is provided. The first electrode terminal 41 is electrically connected to the movable part side electrode 35 by a first wiring 51 described later. That is, the movable portion 33 is electrically connected to the first electrode terminal 41 via the movable portion side electrode 35 and the first wiring 51.

  The second electrode terminal 42 is formed on the main surface 20 a of the semiconductor substrate 20 and in a region outside the region I where the lid portion 50 is provided. The second electrode terminal 42 is electrically connected to the fixed portion side electrode 36 by a second wiring 52 described later. That is, the fixed portion 34 is electrically connected to the second electrode terminal 42 via the fixed portion side electrode 36 and the second wiring 52.

  In addition, the 1st electrode terminal 41, the 2nd electrode terminal 42, the wiring part 43, and the wiring part 44 may be formed on the main surface 20a through the insulating film which is not shown in figure. Thereby, electrical insulation with respect to the semiconductor substrate 20 of each electrode terminal and each wiring part is securable.

  2 to 5 are cross-sectional views schematically showing the configuration of the MEMS element according to the present embodiment. 2 to 5 are sectional views taken along lines AA, BB, CC, and DD, respectively, in FIG.

As the semiconductor substrate 20, an SOI (Silicon On Insulator) substrate is used. In the SOI substrate, an insulating layer 22 is formed on a support substrate 21, and a conductor layer (active layer) 23 is formed on the insulating layer 22. The support substrate 21 can be formed of, for example, silicon (Si). The insulating layer 22 can be formed by, for example, silicon oxide (SiO ₂ ). The conductor layer 23 can be formed of, for example, conductive silicon (Si).

  The thickness of the support substrate 21 can be several tens to several hundreds of μm, for example. The thickness of the insulating layer 22 can be set to several to several tens of μm, for example. The thickness of the conductor layer 23 can be several tens to several hundreds μm, for example. In this embodiment, an example in which an SOI substrate is used is described. However, the semiconductor substrate 20 is not limited to an SOI substrate. For example, conductive polysilicon using surface MEMS technology or nickel ( A plated metal such as Ni) may be used as the conductor layer.

  As shown in FIGS. 2 to 5, the support portion 30, the first beam portion 31, the second beam portion 32, the movable portion 33, and the fixed portion 34 are formed by processing the conductor layer 23 and the insulating layer 22. Has been. That is, the support layer 30, the first beam portion 31, the second beam portion 32, the movable portion 33, and the fixed portion 34 are formed by patterning the conductor layer 23 and the insulating layer 22.

  In the first beam portion 31, the second beam portion 32, and the fixing portion 34, the conductor layer 23 is fixed to the support substrate 21 through the lower insulating layer 22. On the other hand, in the movable portion 33, the insulating layer 22 formed in the lower layer of the conductor layer 23 is removed and is suspended in the space. Accordingly, the movable portion 33 is provided in the element formation area DA of the semiconductor substrate 20 so as to be relatively displaceable with respect to the first beam portion 31, the second beam portion 32, and the fixed portion 34.

  The lid portion 50 is formed on the main surface 20a of the semiconductor substrate 20 so as to cover the element formation region DA. A recess 53 is formed on the surface of the lid 50 facing the semiconductor substrate 20. The lid 50 can be formed of various substrates such as a silicon substrate and a glass substrate.

  The lid part 50 is joined to the support part 30 by, for example, thermocompression bonding, solder bonding, eutectic bonding, or the like. At this time, the element formation region DA is preferably hermetically sealed.

  The first wiring 51 is formed on the surface of the lid 50 that faces the semiconductor substrate 20. The first wiring 51 is formed in the recess 53, that is, on the bottom surface of the recess 53. As described above, the first wiring 51 is formed so as to electrically connect the wiring part 43 and the movable part side electrode 35.

  The second wiring 52 is formed on the surface of the lid 50 that faces the semiconductor substrate 20. Further, the second wiring 52 is formed in the recess 53, that is, on the bottom surface of the recess 53. As described above, the second wiring 52 is formed so as to electrically connect the wiring portion 44 and the fixed portion side electrode 36.

  Even when the first wiring 51 and the second wiring 52 are formed on the bottom surface of the concave portion 53, the depth of the concave portion 53 is such that the lid portion 50 has the first beam portion 31, the second beam portion 32, and the movable portion. It is preferable to have such a depth that it does not contact 33 and the fixing portion 34.

  Moreover, it is preferable that the recessed part 53 has a taper shape in which the opening diameter of the recessed part 53 reduces gradually in the depth direction. This is because the first wiring 51 and the second wiring 52 can be easily formed on the side wall of the concave portion 53 because the concave portion 53 has a tapered shape. As will be described later, when the lid 50 is a silicon single crystal substrate whose surface facing the semiconductor substrate 20 has a (100) plane orientation, for example, the concave portion 53 having such a tapered shape is easily formed. Can do.

  Next, the operation of the MEMS element according to the present embodiment will be described with reference to FIG.

  FIG. 6 is a plan view schematically showing a state where the MEMS element according to the present embodiment is operating as an acceleration sensor.

  When acceleration is applied in the Y direction, the movable portion 33 is elastically deformed and moves in the Y direction. Thereby, the distance of the Y direction between the movable part 33 and the fixed part 34 changes. Accordingly, the capacitance of the capacitive element formed by the movable portion 33 and the fixed portion 34 changes. The acceleration can be measured by detecting this change in capacitance by an external electric circuit or the like. The movable portion 33 is connected to the first electrode terminal 41 via the first wiring 51, and the fixed portion 34 is connected to the second electrode terminal 42 via the second wiring 52. Therefore, by electrically connecting the first electrode terminal 41 and the second electrode terminal 42 to the MEMS element 10 and another capacitance measurement circuit, the capacitance between the movable portion 33 and the fixed portion 34 can be reduced. Changes can be measured. Alternatively, a capacitance measurement circuit is formed on the same semiconductor substrate 20 as the MEMS element 10, and the first electrode terminal 41 and the second electrode terminal 42, or the movable part side electrode 35 and the fixed electrode are fixed to the capacitance measurement circuit. The part side electrode 36 may be electrically connected.

  Next, with reference to FIGS. 7 to 15, a method for manufacturing the MEMS element according to the present embodiment will be described. 7 to 15 are cross-sectional views schematically showing the method for manufacturing the MEMS element according to the present embodiment. 7 and 15 show cross-sectional views taken along line AA in FIG. 1, and FIGS. 8, 9 and 14 show cross-sectional views taken along line BB in FIG. FIG. 13 is a sectional view taken along the line CC in FIG. 7 to 15, the same parts as those in FIGS. 1 to 5 are denoted by the same reference numerals, and the description thereof may be omitted.

  First, in the step shown in FIG. 7, after a conductive film made of, for example, aluminum (Al) is formed on the conductor layer 23 by, for example, a sputtering method, the conductive film is patterned by using a photolithography technique and an etching technique. To do. Thereby, the movable part side electrode 35, the wiring part 43, and the 1st electrode terminal 41 are formed in the main surface 20a of the semiconductor substrate 20 (electrode terminal formation process). Although not shown, the fixed portion side electrode 36, the wiring portion 44, and the second electrode terminal 42 shown in FIG. 1 are also formed by patterning the conductive film. The first electrode terminal 41 and the second electrode terminal 42 are formed in a region outside the region I where the lid portion 50 is provided.

  The material of the conductive film is not limited to aluminum (Al), but various combinations such as gold (Au), copper (Cu), etc., for example, in combination with a bonding material such as gold (Au) wire or solder. A metal material etc. can be used.

  Next, in the process shown in FIG. 8, the conductor layer 23 is patterned by using a photolithography technique and an etching technique to form the support part 30 and the movable part 33. Although not shown, the first beam portion 31, the second beam portion 32, and the fixing portion 34 shown in FIG. 1 are also formed by patterning the conductor layer 23.

  Next, in the process shown in FIG. 9, the movable part 33 is suspended in the space by removing the insulating layer 22 below the movable part 33 by etching. Thereby, the movable part 33 which can move to the Y direction of FIG. 1 can be formed (movable part formation process). On the other hand, the insulating layer 22 below the first beam portion 31, the second beam portion 32, and the fixing portion 34 is not removed. Thereby, the first beam portion 31, the second beam portion 32, and the fixing portion 34 can be fixed to the support substrate 21 via the insulating layer 22.

  Next, in the step shown in FIG. 10, a recess 53 is formed on the surface (lower surface) of the lid 50 facing the semiconductor substrate 20 (recess formation step).

  When the lid 50 is made of, for example, a silicon substrate, the lid 50 is opposed to the semiconductor substrate 20 by wet etching using an alkaline etching solution such as potassium hydroxide (KOH) or tetramethylammonium hydroxide (TMAH). A recess 53 can be formed on the surface (lower surface).

  Further, when the lid 50 is made of a silicon single crystal substrate having a (100) plane orientation on the lower surface, and etching is performed using the above-described alkaline etchant, the silicon single crystal is caused by the anisotropy of the etching rate. The substrate is etched so that the (111) plane is exposed. Accordingly, the opening diameter of the concave portion 53 can be formed to have a tapered shape that gradually decreases in the depth direction, and the conductive film 54 described later cannot cover the side wall of the concave portion 53, and the conductive film 54 has the concave portion 53. Can be prevented from being interrupted at the side wall.

  Or when the cover part 50 consists of glass substrates, for example, the recessed part 53 can be formed in the lower surface of the cover part 50 by wet etching using etching liquid, such as a hydrofluoric acid, for example.

  Next, in the step shown in FIG. 11, a conductive film 54 is formed on the surface of the lid 50 facing the semiconductor substrate 20.

  For example, the conductive film 54 made of, for example, aluminum (Al) is formed by sputtering.

  When the lid 50 is made of, for example, a silicon substrate, an insulating film made of, for example, silicon oxide is formed in advance on the surface of the lid 50 facing the semiconductor substrate 20 by, for example, a CVD (Chemical Vapor Deposition) method. The conductive film 54 may be formed through an insulating film.

  Next, in a step shown in FIG. 12, a resist film 55 is formed on the surface of the lid 50 where the conductive film 54 is formed, facing the semiconductor substrate 20, and the resist film 55 is patterned by using a photolithography technique. To do. Thereby, a mask pattern for forming the first wiring 51 and the second wiring 52 is formed.

  Next, in the step shown in FIG. 13, the conductive film 54 is patterned by an etching technique using a mask pattern made of the resist film 55. Thereby, the 1st wiring 51 and the 2nd wiring 52 can be formed (wiring formation process).

When the conductive film 54 is made of aluminum (Al), for example, wet etching using an alkaline etching solution or dry etching using an etching gas such as chlorine gas (Cl ₂ ) is used as an etching technique. it can.

  14 and 15, the lid 50 is bonded to the support 30 of the semiconductor substrate 20 (bonding process). As a bonding method, for example, direct bonding such as thermocompression bonding or room temperature bonding using surface activation by plasma or ions can be used. Further, for example, indirect bonding such as solder bonding or eutectic bonding can be used. Further, for example, bonding with an adhesive such as glass frit can be used.

  For example, the lid portion 50 is disposed on the support portion 30 of the semiconductor substrate 20 so that the lid portion 50 covers the element formation region DA in a state where the surface on which the concave portion 53 is formed faces the main surface 20a of the semiconductor substrate 20. Then, the lid part 50 is bonded to the support part 30 by performing heat treatment in a state where the lid part 50 is pressurized to the support part 30. At this time, in the cross section taken along the line BB in FIG. 1, as shown in FIG. 14, the portion where the first wiring 51 of the lid portion 50 is not formed and the movable portion side electrode 35 of the support portion 30 are formed. The part which is not done is joined. Moreover, in the cross section along the AA line in FIG. 1, as shown in FIG. 15, while the 1st wiring 51 and the movable part side electrode 35 are joined, the 1st wiring 51 and the wiring part 43 are connected. Be joined. As a result, in the cross section taken along line BB in FIG. 1, the lid 50 and the support 30 are joined as shown in FIG. And in the cross section along the AA line in FIG. 1, as shown in FIG. 2, while the 1st wiring 51 and the movable part side electrode 35 are joined, the 1st wiring 51 and the wiring part 43 are connected. Be joined. Although not shown, the second wiring 52 and the fixed portion side electrode 36 are joined, and the second wiring 52 and the wiring portion 44 are joined.

  The lid part 50 is joined to the support part 30 by thermocompression bonding, soldering or eutectic bonding, so that the first electrode terminal 41 and the movable part side electrode 35 are electrically connected via the first wiring 51. It can be connected well. Further, the lid 50 is bonded to the support 30 by thermocompression bonding, solder bonding, or eutectic bonding, so that the second electrode terminal 42 and the fixed portion side electrode 36 are electrically connected via the second wiring 52. Can be connected well.

In addition, when the lid 50 is bonded to the support 30, the element formation region DA may be vacuum sealed by bonding in a reduced-pressure atmosphere such as in a vacuum. Alternatively, the element formation region DA may be sealed in an inert atmosphere by bonding in an inert atmosphere gas such as nitrogen (N ₂ ) gas.

  Further, the above-described steps may be performed for each element, that is, at the chip level. However, it may be performed in a state where the elements are not separated, that is, at the wafer level. Then, after performing the above steps at the wafer level, dicing may be performed for each element.

  Next, with reference to FIG. 16 and FIG. 17, the effect that the MEMS element according to the present embodiment can reduce the element area will be described in comparison with Comparative Example 1. FIG.

  FIG. 16 is a plan view schematically showing the configuration of the MEMS element according to Comparative Example 1. FIG. 17 is a cross-sectional view schematically showing the configuration of the MEMS element according to Comparative Example 1. 17 is a cross-sectional view taken along line BB in FIG.

  Similar to the MEMS element 10 according to the first embodiment, the MEMS element 110 according to the comparative example 1 includes the semiconductor substrate 120, the support part 130, the first beam part 131, the second beam part 132, and the movable part 133. , Fixed part 134, movable part side electrode 135, fixed part side electrode 136, first electrode terminal 141, second electrode terminal 142, wiring parts 143 and 144, lid part 150, first wiring 151 and second A wiring 152 is provided. The semiconductor substrate 120 includes a support substrate 121, an insulating layer 122, and a conductor layer (active layer) 123.

  The semiconductor substrate 120, the support part 130, the movable part 133, the fixed part 134, the movable part side electrode 135, the fixed part side electrode 136, the first electrode terminal 141, the second electrode terminal 142, and the wiring parts 143 and 144 are The semiconductor substrate 20, the support part 30, the movable part 33, the fixed part 34, the movable part side electrode 35, the fixed part side electrode 36, the first electrode terminal 41, and the second electrode of the MEMS element 10 according to the first embodiment. The terminal 42 and the wiring portions 43 and 44 have the same structure, and a description thereof is omitted. The support substrate 121, the insulating layer 122, and the conductor layer (active layer) 123 have the same structure as the support substrate 21, the insulating layer 22, and the conductor layer (active layer) 23 of the MEMS element 10 according to the first embodiment. Therefore, the description is omitted.

  In the MEMS element 110 according to the comparative example 1, the first wiring 151 that connects the first electrode terminal 141 and the movable portion side electrode 135 is formed on the upper surface of the first beam portion 131. Therefore, as shown in FIG. 16, in order to form the first wiring 151 bypassing the movable portion 133 such as when the first electrode terminal 141 and the first beam portion 131 are not in a straight line, It is necessary to provide a connection portion 137 that connects the first beam portion 131 and the support portion 130. For example, in order to form the connection portion 137, it is necessary to increase the length of the element formation region DA in the Y direction from Y0 shown in FIG. 1 to Y0 + Y1 shown in FIG. When the length of the element formation region DA in the X direction is the same as X0 shown in FIG. 1, the element area is increased by X0 × Y1.

  On the other hand, in the MEMS element 10 according to the first embodiment, the first wiring 51 that connects the first electrode terminal 41 and the movable portion side electrode 35 is on the surface of the lid portion 50 that faces the semiconductor substrate 20. Is formed. Therefore, it is not necessary to provide the connection portion 137 in the MEMS element 110 according to Comparative Example 1, and the element area can be reduced by X0 × Y1.

  Next, with reference to FIG. 18, the effect that the MEMS element according to the present embodiment can reduce the manufacturing cost will be described in comparison with Comparative Example 2.

  FIG. 18 is a cross-sectional view schematically showing the configuration of the MEMS element according to Comparative Example 2.

  The structure of the MEMS element 210 according to the comparative example 2 is the same as that of the MEMS element 10 according to the first embodiment, except for the lid portion 250, and the same reference numerals as those of the MEMS element 10 are given to omit the description. To do.

  In the MEMS element 210 according to the comparative example 2, the first wiring 251 connecting the first electrode terminal 41 and the movable portion side electrode 35 is opposite to the upper surface of the lid portion 250, that is, the surface facing the semiconductor substrate 20. It is formed on the side surface. In addition, an opening 255 is formed in a portion of the lid 250 that overlaps the movable part side electrode 35 in plan view, and the first wiring 251 and the movable part side electrode 235 are electrically connected to the opening 255. A through electrode 239 to be connected is provided. Therefore, a process for forming the opening 255 in the lid 250 is required, and the manufacturing cost increases.

  On the other hand, in the MEMS element 10 according to the first embodiment, the first wiring 51 that connects the first electrode terminal 41 and the movable portion side electrode 35 is on the surface of the lid portion 50 that faces the semiconductor substrate 20. Is formed. Therefore, it is not necessary to form the opening 255 of the lid 250 in the MEMS element 210 according to the comparative example 2, and the manufacturing cost can be reduced.

  Further, as shown in FIG. 1, even when the first beam portion 31 is not directly connected to the side on which the first electrode terminal 41 of the support portion 30 is formed, the first beam portion 31 is connected to the first beam portion 31. The wiring length of the first wiring 51 that electrically connects the movable portion 33 and the first electrode terminal 41 can be shortened. In addition, when the second beam portion 32 is not directly connected to the side of the support portion 30 where the second electrode terminal 42 is formed, the fixed portion 34 connected to the second beam portion 32 and the second portion The wiring length of the second wiring 52 that electrically connects the two electrode terminals 42 can be shortened.

In the present embodiment, an example in which the second beam portion 32 and the fixing portion 34 are provided has been described. However, the second beam portion 32 and the fixing portion can be fixed by, for example, causing the support portion 30 to function as the fixing portion. The part 34 may not be provided.
(Second Embodiment)
Next, a MEMS element and a method for manufacturing the MEMS element according to the second embodiment of the present invention will be described.

  First, the MEMS element according to this embodiment will be described with reference to FIGS.

  The MEMS element according to the present embodiment is different from the MEMS element according to the embodiment in that the lid portion is not provided with a recess.

  FIG. 19 is a plan view schematically showing the configuration of the MEMS element according to the present embodiment. 20 to 23 are cross-sectional views schematically showing the configuration of the MEMS element according to the present embodiment. 20 to 23 are cross-sectional views taken along lines AA, BB, CC, and DD in FIG. 19, respectively.

  The MEMS element 10a includes a semiconductor substrate 20, a support portion 30, a first beam portion 31, a second beam portion 32, a movable portion 33, a fixed portion 34, a first electrode terminal 41, a second electrode terminal 42, a lid. A portion 50a, a first wiring 51, and a second wiring 52 are included. A region on the main surface 20a of the semiconductor substrate 20 where the first beam portion 31, the second beam portion 32, the movable portion 33, and the fixed portion 34 are formed is referred to as an element formation region DA. This is the same as the first embodiment.

  In FIG. 19, the lid 50a, the first wiring 51, and the second wiring 52 are not shown for ease of illustration. However, in FIG. 19, the region of the main surface 20 a of the semiconductor substrate 20 where the lid portion 50 a is provided is indicated by the same region I as the region where the pedestal portion 38 is provided. A region where the first wiring 51 of the lid 50a is formed is indicated by a region II surrounded by a dotted line, and a region where the second wiring 52 of the lid 50a is formed is surrounded by a dotted line. As shown in region III.

  The semiconductor substrate 20, the movable portion 33, the fixed portion 34, the first electrode terminal 41, and the second electrode terminal 42 are the semiconductor substrate 20, the movable portion 33, and the fixed portion 34 of the MEMS element 10 according to the first embodiment. The first electrode terminal 41 and the second electrode terminal 42 have the same structure and will not be described.

  The support part 30 is different from the support part 30 of the MEMS element 10 according to the first embodiment in that a pedestal part 38 is provided on the support part 30. The pedestal portion 38 is made of, for example, a polysilicon film. The movable portion side electrode 35, the fixed portion side electrode 36, and the wiring portions 43 and 44 are formed on the pedestal portion 38.

  The lid part 50a is formed on the pedestal part 38 so as to cover the element formation region DA. A concave portion is not formed on the surface of the lid portion 50a facing the semiconductor substrate 20. The lid 50a can be formed of, for example, a glass substrate.

  Similar to the first embodiment, the lid 50a is joined to the pedestal 38 by, for example, thermocompression bonding, solder bonding, eutectic bonding, or the like. At this time, the element formation region DA is preferably hermetically sealed.

  The first wiring 51 is formed on the surface of the lid part 50a facing the semiconductor substrate 20 so as to electrically connect the wiring part 43 and the movable part side electrode 35. The second wiring 52 is formed on the surface of the lid portion 50a facing the semiconductor substrate 20 so as to electrically connect the wiring portion 44 and the fixed portion side electrode 36.

  Even when the first wiring 51 and the second wiring 52 are formed on the surface of the lid 50a facing the semiconductor substrate 20, the height of the pedestal 38 is such that the lid 50a is the first beam 31 and the second It is preferable to have a height that does not contact the two beam portions 32, the movable portion 33, and the fixed portion 34.

  The operation of the MEMS element according to the present embodiment is the same as the operation of the MEMS element according to the first embodiment.

  Next, with reference to FIGS. 24 to 32, a method for manufacturing the MEMS element according to the present embodiment will be described. 24 to 32 are cross-sectional views schematically showing the method for manufacturing the MEMS element according to the present embodiment. 24 and 32 show cross-sectional views along the line AA in FIG. 19, and FIGS. 25, 26 and 31 show cross-sectional views along the line BB in FIG. FIG. 30 is a sectional view taken along the line CC in FIG. 24 to 32, the same portions as those in FIGS. 19 to 23 are denoted by the same reference numerals, and the description thereof may be omitted.

  First, in the step shown in FIG. 24, after a pedestal film made of, for example, polysilicon is formed by, eg, CVD, the pedestal film is patterned by using a photolithography technique and an etching technique. Thereby, the base part 38 is formed. Further, a conductive film made of, for example, aluminum (Al) exemplified in the first embodiment is formed on the pedestal portion 38 by, for example, a sputtering method, and then the conductive film is formed by using a photolithography technique and an etching technique. Is patterned. Thereby, the movable part side electrode 35, the wiring part 43, and the 1st electrode terminal 41 are formed in the main surface 20a of the semiconductor substrate 20 via the base part 38 (electrode terminal formation process). Although not shown, the fixed portion side electrode 36, the wiring portion 44, and the second electrode terminal 42 shown in FIG. 19 are also formed by patterning the conductive film. And the 1st electrode terminal 41 and the 2nd electrode terminal 42 are formed in the area | region outside the area | region I in which the cover part 50a is provided.

  Next, in the process shown in FIG. 25, the conductor layer 23 is patterned by using a photolithography technique and an etching technique, and the support part 30 and the movable part 33 are formed. Although not shown, the first beam portion 31, the second beam portion 32, and the fixing portion 34 shown in FIG. 19 are also formed by patterning the conductor layer 23.

  Next, in the process shown in FIG. 26, the movable portion 33 is suspended in the space by removing the insulating layer 22 in the lower layer of the movable portion 33 by etching. Thereby, the movable part 33 which can move to the Y direction of FIG. 19 can be formed (movable part formation process). On the other hand, the insulating layer 22 below the first beam portion 31, the second beam portion 32, and the fixing portion 34 is not removed. Thereby, the first beam portion 31, the second beam portion 32, and the fixing portion 34 can be fixed to the support substrate 21 via the insulating layer 22.

  Next, in the step shown in FIG. 27, a lid 50a is prepared. As described above, the lid 50a made of, for example, a glass substrate is prepared.

  Next, in the steps shown in FIGS. 28 to 30, like the steps shown in FIGS. 11 to 13, the conductive film 54 is formed on the surface of the lid 50 a facing the semiconductor substrate 20, and the resist film 55 is formed. Then, a mask pattern is formed, and the conductive film 54 is patterned by an etching technique. Thereby, the 1st wiring 51 and the 2nd wiring 52 can be formed (wiring formation process).

  Next, in the process shown in FIGS. 31 and 32, the lid 50a is joined to the pedestal 38 of the semiconductor substrate 20 (joining process). The joining method can be the same as the joining method in the first embodiment.

  In the cross section taken along line BB in FIG. 19, as shown in FIG. 31, the portion where the first wiring 51 of the lid portion 50a is not formed and the movable portion side electrode 35 of the pedestal portion 38 are not formed. The parts are joined by thermocompression bonding. Moreover, in the cross section along the AA line in FIG. 1, as shown in FIG. 32, while the 1st wiring 51 and the movable part side electrode 35 are joined, the 1st wiring 51 and the wiring part 43 are connected. Be joined.

  Similarly to the first embodiment, when the lid 50a is joined to the pedestal 38, the element formation area DA may be vacuum-sealed, and the element formation area DA is sealed under an inert atmosphere. May be. Further, the above-described steps may be performed at the chip level or at the wafer level.

  Also in the MEMS element according to the present embodiment, the first wiring 51 that connects the first electrode terminal 41 and the movable portion side electrode 35 is formed on the surface facing the semiconductor substrate 20 of the lid portion 50a. The element area can be reduced.

  Also, in the MEMS element according to the present embodiment, the first wiring 51 that connects the first electrode terminal 41 and the movable portion side electrode 35 is formed on the surface of the lid portion 50a that faces the semiconductor substrate 20. Therefore, the manufacturing cost can be reduced.

  Also in the present embodiment, the second beam portion 32 and the fixing portion 34 may not be provided, for example, by causing the support portion 30 to function as a fixing portion.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be modified or changed.

DESCRIPTION OF SYMBOLS 10 MEMS element 20 Semiconductor substrate 20a Main surface 21 Support substrate 22 Insulating layer 23 Conductor layer 30 Support part 33 Movable part 34 Fixed part 35 Movable part side electrode 36 Fixed part side electrode 41 First electrode terminal 42 Second electrode terminal 50 Lid 51 First wiring 52 Second wiring 53 Recess

Claims (10)

A semiconductor substrate;
A movable portion provided on the main surface of the semiconductor substrate so as to be capable of relative displacement with respect to the semiconductor substrate;
A lid provided on the main surface of the semiconductor substrate so as to cover the movable part;
A first electrode terminal provided on a region outside the lid portion on the main surface of the semiconductor substrate;
A MEMS element formed on a surface of the lid portion facing the semiconductor substrate and having a first wiring that electrically connects the first electrode terminal and the movable portion. The lid portion has a recess formed on a surface facing the semiconductor substrate,
The MEMS element according to claim 1, wherein the first wiring is formed in the recess.   The MEMS device according to claim 2, wherein the concave portion has an opening diameter that decreases in a depth direction.   The MEMS element according to claim 1, wherein the lid is bonded to the semiconductor substrate by thermocompression bonding, solder bonding, or eutectic bonding. A fixing portion provided on the main surface of the semiconductor substrate, and fixed to the semiconductor substrate;
A second electrode terminal provided on a region outside the lid portion on the main surface of the semiconductor substrate;
Formed on a surface of the lid portion facing the semiconductor substrate, and having a second wiring for electrically connecting the second electrode terminal and the fixing portion;
5. The MEMS element according to claim 1, wherein the lid portion is provided on the main surface of the semiconductor substrate so as to cover the movable portion and the fixed portion. A movable part forming step of forming a movable part relative to the semiconductor substrate on the main surface of the semiconductor substrate;
An electrode terminal forming step of forming a first electrode terminal on the main surface of the semiconductor substrate and outside a region where a lid is provided;
Forming a first wiring for electrically connecting the first electrode terminal and the movable portion on one surface of the lid portion; and
The lid portion on which the first wiring is formed is configured such that the lid portion covers the movable portion in a state where the one surface of the lid portion faces the main surface of the semiconductor substrate, and the first portion A method for manufacturing a MEMS element, comprising: a bonding step of bonding to the semiconductor substrate such that an electrode terminal and the movable portion are electrically connected via the first wiring. A recess forming step of forming a recess in the one surface of the lid,
The method of manufacturing a MEMS element according to claim 6, wherein in the wiring formation step, the first wiring is formed in the recess.   The recess forming step is to form the recess so that the opening diameter is reduced in the depth direction by etching the one surface of the lid made of a silicon substrate with an alkaline etchant. The manufacturing method of the MEMS element of Claim 7.   9. The method of manufacturing a MEMS element according to claim 6, wherein in the bonding step, the lid is bonded to the semiconductor substrate by thermocompression bonding, solder bonding, or eutectic bonding. The movable part forming step forms a fixed part fixed to the semiconductor substrate together with the movable part on the main surface of the semiconductor substrate.
The electrode terminal forming step is to form a second electrode terminal together with the first electrode terminal outside a region where the lid portion is provided,
The wiring forming step forms a second wiring for electrically connecting the second electrode terminal and the fixing portion together with the first wiring on the one surface of the lid portion. And
In the bonding step, the lid portion on which the first wiring and the second wiring are formed is arranged such that the one surface of the lid portion faces the main surface of the semiconductor substrate. Covers the movable part and the fixed part, and the first electrode terminal and the movable part are electrically connected via the first wiring, and the second electrode terminal and the fixed part 10. The method of manufacturing a MEMS element according to claim 6, wherein the semiconductor element is bonded to the semiconductor substrate so as to be electrically connected via the second wiring. 11.

Images