JP2010030021A - Electronic device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of an electronic device capable of properly etching a sacrificial layer to release a movable part even if a gap becomes smaller in an electronic device with the movable part having a gap from a function structure body constituting a function element, and a manufacturing method therefor. <P>SOLUTION: This electronic device 10 comprises a substrate 11, a function structure body 13 formed on the substrate and having a movable part 13m with a gap 13g at a lower part, a monitoring structure 14 formed of the same layer as the movable part on the substrate and having a deformation part 14m having a gap 14g at a lower part and vertically deformable more easily than the movable part due to its planar shape, and a detecting structure 14r fixed on the deformation part and taking a posture according to the deformation state of the deformation part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic device and a manufacturing method thereof, and more particularly to a structure and a manufacturing method of an electronic device formed by releasing a MEMS element and other functional elements by sacrificial layer etching.

  In general, a MEMS element such as a microactuator, a vibrator, or a sensor, or a functional element such as a semiconductor sensor is formed by forming a structure together with a sacrificial layer and then performing sacrificial layer etching to release the structure. At this time, as an end point of release etching, an appropriate etching time is usually determined in advance by experiments or the like in many cases. Also known are a method of monitoring the amount of substances generated during etching and the consumption of etching gas, and a method of optically analyzing the material of the etched surface.

  However, the above MEMS element and other functional elements are often formed with a movable part having a gap below as a part of the structure, and in such a case, the monitoring and optical elements described above are used. In the end, it is difficult to perform a specific analysis, so in the end, it is necessary to rely on a method for determining the end point of the release etching by managing the etching time.

  As a management method of release etching in the manufacturing process of a structure having a movable part having a gap below as described above, for example, in Patent Document 1 below, a monitor element 20 having a large number of monitor fingers 30 and 50 is provided. A method is described in which the release state of the MEMS element 10 is confirmed by appropriately providing it in the formation region of the MEMS element 10 and observing the planar spread of the sacrificial layer etching on the monitor element 20.

Further, in Patent Document 2 below, one or a plurality of etching monitor structures configured in a cantilevered or doubly-supported mesh form are provided, and whether these structures are stuck during sacrificial layer etching. A method for avoiding insufficient etching or excessive etching by confirming whether or not there is described (see FIGS. 1 to 5).
JP 2007-83341 A JP 2001-298012 A

  However, in the method using the monitor element described above, the range in which the sacrificial layer around or above the monitor element has been etched is visually checked. If the gap in the structure becomes smaller and etching in the gap becomes difficult to proceed, the etching range of the sacrificial layer below the movable part and the etching range around and above the structure will greatly differ, and how much the structure is There is a problem that it is impossible to know exactly whether it has been released.

  Further, in the method using the etching monitor structure described above, since the change in the appearance of the monitor structure is reduced by reducing the gap, it is difficult to confirm whether or not the structure is stuck. In many cases, the MEMS structure is housed and disposed in a housing recess formed in a substrate covering structure in which an insulating layer and a wiring layer are laminated. In the case of being housed and disposed in the same housing recess as the element, it is assumed that it is more difficult to confirm whether or not the monitor structure is stuck.

  Therefore, the present invention solves the above-described problems, and the problem is that an electronic device in which a functional structure constituting a functional element includes a movable part having a gap below, even if the gap is reduced. An object of the present invention is to provide a structure and a manufacturing method of an electronic device that can appropriately perform sacrificial layer etching for releasing a movable part.

  In view of such circumstances, the electronic device of the present invention is formed of a substrate, a functional structure including a movable portion formed on the substrate and having a gap below, and the same layer as the movable portion on the substrate. A monitor structure having a deformed portion that has a gap below and is configured to be more easily deformed in the vertical direction than the movable portion by a planar shape thereof, and is fixed on the deformed portion, and the deformed portion is deformed. And a detection structure having a posture corresponding to the state.

  According to the present invention, the monitor structure including the deformable portion formed of the same layer as the movable portion and configured to be easily deformed in the vertical direction from the movable portion is provided, and the monitor structure on the deformable portion of the monitor structure. By forming a fixed detection structure, when the deformed portion is deformed, the deformation structure can be easily confirmed by checking the posture of the detection structure corresponding to the deformed portion. The deformation | transformation aspect of the movable part of a structure can be guessed. In particular, a great effect can be obtained when checking the suitability of the etching amount at the time of release etching of the functional structure by looking at the posture of the detection structure.

  In one aspect of the present invention, a flat light reflecting surface is provided on the upper surface of the detection structure. According to this, it becomes possible to know the inclination of the posture of the detection structure more reliably and accurately by the flat light reflection surface. This light reflecting surface can be a surface having a higher light reflectivity than the surface of the monitor structure in the lower layer.

  In another aspect of the present invention, the apparatus further includes a substrate covering structure in which one or more sets of an insulating layer and a wiring layer are stacked on the substrate, and the functional structure is accommodated in the substrate covering structure. A function accommodating recess and a monitor accommodating recess for accommodating the monitor structure are provided. According to this, when both the functional structure and the monitor structure are disposed in the housing recess provided in the substrate covering structure, the posture is confirmed by providing the detection structure on the monitor structure. Therefore, it is possible to further increase the effect that the deformation state of the deformation portion can be easily confirmed.

  In this case, it is preferable that the function accommodating recess and the monitor accommodating recess have the same opening shape and opening area. Since the opening shape and the opening area of both receiving recesses are configured to be the same, release etching is performed in a state where there is little difference in conditions, so the relationship between the manufacturing state of the functional structure and the monitoring structure can be confirmed. Since it can be further enhanced, it becomes possible to perform production with high reproducibility and stability.

  Further, in this case, the detection structure further includes a first coating layer provided with a pore covering the functional housing recess and a second coating layer closing the pore, and the detection structure has a pore. An upper layer is preferably provided. According to this, release etching can be performed through the pores of the first coating layer, and by providing the second coating layer, the pores can be closed and the functional structure can be enclosed in the housing recess. Further, by providing an upper layer with pores in the detection structure as well as the first coating layer, the relationship between the etching state of the functional structure and the monitoring structure during release etching can be enhanced. .

  In each of the above inventions, it is desirable that the detection structure is in an inclined posture by the deformation of the deformation portion. According to this, it is possible to confirm that the etching amount at the time of release etching is not insufficient by configuring the detection structure to be in an inclined posture by the deformation of the deformation portion.

  Further, it is desirable that the deforming portion has a longer length from the support portion to the tip portion or between the support portions than the movable portion, and a width along the support portion is small. According to this, since the deformable part is composed of the same layer as the movable part, the material and thickness are common, so the length from the support part to the tip part (in the case of a cantilever), or the support part The length of the gap (in the case of both-end support) is larger than the movable part and the width along the support part is small. Even when the range of the support portion and the length change according to the amount of layer etching, the sacrificial layer etching under the deformable portion is more likely to proceed than the sacrificial layer etching under the movable portion. It can be configured to bend and deform easily in the vertical direction.

  Next, in the method for manufacturing an electronic device according to the present invention, a functional structure including a movable portion on which a sacrificial layer is disposed on a substrate, and the same layer as the movable portion is formed. A monitor structure provided with a deformed portion that is arranged and is more easily deformed in the vertical direction than the movable portion due to its planar shape, and a posture that is fixed on the deformed portion and that corresponds to the deformed state of the deformed portion A structure forming step for forming a detection structure, a release step for forming a gap below the movable portion and the deformable portion by etching the sacrificial layer, and the detection structure after the release step An inspection process for confirming the posture of the body.

  In one aspect of the present invention, a flat light reflecting surface is provided on the upper surface of the detection structure in the structure forming step, and a light reflecting state of the light reflecting surface is confirmed in the inspection step.

  In another aspect of the present invention, the structure forming step includes a lower formation step of forming the functional structure and the monitor structure, and an insulating layer on the functional structure and the monitor structure. And an upper forming step of providing a substrate covering structure in which the detection structure is constituted by one or a plurality of wiring layers, wherein one or a plurality of wiring layers are laminated, and in the release step, The functional structure is separated from the substrate covering structure by removing the portion of the insulating layer on the functional structure and the portion of the insulating layer on the monitoring structure together with the sacrificial layer. And a functional housing recess for housing the functional structure, and the monitor structure and the detection structure are separated from the substrate covering structure, and the monitor structure and the detection Monitor housing recess structure is accommodated is provided.

  In this case, the first covering layer having pores is formed above the functional structure in the upper formation step, and at the same time, the pores of the inspection structure are provided above the monitoring structure. An upper layer is formed, and in the release step, etching is performed through the pores of the first coating layer and the upper layer, and the second coating layer that closes the pores of the first coating layer after the release step. Is preferably formed.

  In the present specification and the appended claims, the terms “vertical direction”, “upper”, “upper”, “lower”, “lower” and the like are functional elements or In the device structure in which the functional structure is provided, it expresses the case where the substrate side is the lower or lower side, and the functional element or functional structure side is the upper or upper side, and represents the actual vertical direction depending on the posture of the device , Does not mean the upper, upper, lower and lower parts in the vertical direction.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]
1A to 1E are process cross-sectional views illustrating the structure and manufacturing method of an electronic device 10 according to a first embodiment of the present invention. In this embodiment, as shown in FIG. 1A, a bulk MEMS manufacturing method using an SOI substrate in which an insulating layer 12 such as a silicon oxide film is formed on the surface of a substrate 11 made of a semiconductor such as single crystal silicon. Indicates.

  As shown in FIG. 1B, a conductive layer made of conductive polysilicon or the like is formed on the insulating layer 12 by using a sputtering method, a CVD method, or the like, and is patterned so that the functional structure 13 and the monitor are formed. The structural body 14 is formed. The functional structure 13 is shown in a simplified form in the illustrated example. In this embodiment, the monitoring structure 14 is performed together with the functional structure 13 in the same film formation stage and patterning stage. In each figure, the planar shapes of the functional structure 13 and the monitor structure 14 are simplified, and are also shown at positions immediately above the process cross-sectional views.

  In the present embodiment, the functional structure 13 and the monitor structure 14 are formed in the same process as described above, so that the functional structure 13 and the monitor structure 14 are made of the same material and are the same. The thickness is assumed to be as follows. However, the planar shapes are different from each other for reasons described later.

  Next, as shown in FIG. 1 (c), a light reflecting layer made of metal such as aluminum or aluminum alloy is formed on the functional structure 13 and the monitor structure 14, and patterned to detect the structure. Form bodies 13r, 14r. In the case of the present embodiment, these detection structures 13r and 14r constitute a flat light reflection surface, so that the postures of the functional structure 13 and the monitor structure 14 can be easily detected optically. In the case of this embodiment, the detection structures 13r and 14r are formed of a wiring layer. That is, it is formed of the same material simultaneously with other wiring patterns (not shown) in the wiring layer forming step.

  Since the monitor structure 14 is composed of the same layer as the functional structure 13, it is not easy to obtain a surface that is easy to see, but the detection structures 13r and 14r are different from the above layers. Therefore, it is possible to select a layer with good visibility. In the present embodiment, by forming the detection structures 13r and 14r using the wiring layer, the upper surfaces having higher light reflectivity than the functional structure 13 and the monitor structure 14 can be formed on the detection structures 13r and 14r. .

  Thereafter, as shown in FIG. 1D, the detection structures 13r and 14r are covered with protective layers 13c and 14c made of a resin such as a silicon nitride film or a resist. The protective layers 13c and 14c protect the detection structures 13r and 14r from the etching process when the detection structures 13r and 14r are not resistant to the etching process of the release process described later or are insufficient. Is to do. Therefore, when the detection structures 13r and 14r have sufficient etching resistance, the protective layer is not necessary. The protective layers 13c and 14c are preferably formed simultaneously with an etching mask for protecting other structures, for example, during the release process. Moreover, it is preferable that the protective layers 13c and 14c have translucency in order to use the light reflecting surface, and the silicon nitride films and resists exemplified above satisfy this condition. In addition, when the protective layers 13c and 14c do not have translucency, it is necessary to perform observation as described later after the protective layers 13c and 14c are removed.

  Thereafter, a release process for etching the insulating layer 12 is performed. In this release process, wet etching is performed using an etchant such as buffered hydrofluoric acid (BHF). By this wet etching, the insulating layer 12 formed under the functional structure 13 and the monitor structure 14 is removed, and the functional structure 13 and the monitor structure 14 are formed under the functional structure 13 and the monitor structure 14 as shown in FIG. By leaving a part of the insulating layer 12, the support portion 13 s of the functional structure 13 and the support portion 14 s of the monitor structure 14 are formed.

  Further, the part of the functional structure 13 arranged on the gap 13g where the support part 13s does not exist becomes a movable part 13m, and the movable part 13m is an operation part for realizing the function of the functional structure 13 (for example, Vibration part, deformation part). Further, the portion of the monitor structure 14 disposed on the gap 14g where the support portion 14s does not exist becomes a deformed portion 14m, and the deformable portion 14m is a deformed portion for detecting the progress of etching by the monitor structure 14. It becomes.

  In the case of this embodiment, the deforming part 14m has a shape that is more easily bent and deformed in the vertical direction than the movable part 13m. That is, in the illustrated example, the length from the support portion 13s to the outer edge (tip) of the movable portion 13m is Ls, and the width in the direction orthogonal to the length Ls (the direction along the support portion 13s) is Ws. When the length from the support portion 14s to the outer edge (tip) of the portion 14m is Ls 'and the width in the direction orthogonal to the length Ls' (direction along the support portion 14s) is Ws ', Ls'> Ls , Ws ′ <Ws. If it does in this way, the deformation | transformation part 14m will become easy to bend and deform along the said length direction, As a result, as shown in FIG.1 (e), the deformation | transformation part 14m is sticking (lower layer) in the release process rather than the movable part 13m. Sticking to the structure) is likely to occur.

  The sticking described above mainly occurs when the deformed portion 14m is drawn downward by the surface tension of the moisture in the process of reducing the moisture in the gap 14g during the drying after the cleaning in the release process. In this embodiment, the deformation portion 14m is intentionally caused to stick, but the movable portion 13m is not sticking.

  In general, the cause of sticking in the movable portion 13m is dimensional variation of the movable portion 13m, excessive etching amount, or the like. In this embodiment, in order to prevent the support portion 13s from eroding due to an excessive etching amount, the etching is stopped when a certain degree of deformation or sticking occurs in the deformation portion 14m.

  In the case of the present embodiment, since the material and thickness of the functional structure 13 and the monitor structure 14 are the same, and the gaps 13g and 14g are also the same, the deformed portion 14m is set in the vertical direction as compared with the movable portion 13m as described above. In order to be easily bent and deformed, it is necessary to make the planar shape of the portion to be the deforming portion 14m of the monitor structure 14 different from the planar shape of the portion to be the movable portion 13m of the functional structure 13. . In the case of the illustrated example, the sacrificial layer 12B in the gap 14g is formed by making the portion to be the deformed portion 14m of the monitor structure 14 narrow (Ws ′ <Ws) and further extending the portion. Ls ′> Ls is established by etching to a deep region.

  In the present embodiment, the sacrificial layer 12B in the gap 14g is completely removed, so that the deformed portion 14m undergoes large deformation or sticking. At this time, the etching amount of the gap 13g under the movable portion 13m However, when the sacrificial layer 12B in the gap 14g remains in the vicinity of the support portion 14s, for example, deformation or sticking occurs. Moreover, the etching amount of the gap 13g under the movable portion 13m may be configured to be appropriate at this time. This also applies to the other embodiments described below.

  The support portion 13s constituted by the etching residue of the insulating layer 12 as described above is reduced when the etching time in the release process is too long and does not function as a support portion, and when the etching time is too short, the support portion 13s Therefore, there is a problem in the operation of the functional structure 13. Therefore, management of the etching amount in the release process is extremely important. In the present embodiment, the monitor structure 14 is provided as described above, and the deformable portion 14m is configured to be bent and deformed more easily in the vertical direction than the movable portion 13m, so that the deformable portion 14m is sticked after the release process. However, the movable portion 13m is configured so as to obtain a necessary etching amount for the functional structure 13 as long as the movable portion 13m does not cause sticking. Further, it is configured such that the etching amount of the gap 13g does not become excessive when the deforming portion 14m causes sticking. As a result, it can be seen that the etching amount for the functional structure 13 is insufficient if the deformed portion 14m does not stick after the release process, and the etching amount for the release process for the functional structure 13 can be secured by further etching. In addition, if the etching is stopped when the deforming portion 14m is stuck, it is possible to prevent the etching amount with respect to the functional structure 13 from becoming excessive.

  In the present embodiment, the detection structure 14r is provided on the deformation portion 14m of the monitor structure 14, and the detection structure 14r is configured such that the posture is changed by the deformation of the deformation portion 14m. By visually recognizing the detection structure 14r, it can be known that the deformation portion 14m is deformed. In particular, since the detection structure 14r constitutes a light reflecting surface, it can be easily grasped even with a slight inclination, and is particularly suitable for inspection by observation using a metal microscope. It can also be easily detected by image processing via an imaging device such as a camera.

  The purpose of detecting the posture of the detection structure 14r is mainly whether or not the monitor structure 14 is sticking, but the deforming portion 14r bends in the vertical direction even if the sticking is not complete. If any deformation occurs, this can be detected by the detection structure 14r. Therefore, it is also possible to detect the etching amount in the release process in more detail according to the posture of the detection structure 14r. For example, as shown in FIG. 1 (e), if the posture change of the detection structure 14r is detected by the angle of the reflected light, and the relationship between this angle and the etching amount is derived in advance through experiments or the like, the etching amount can be reduced. It can be detected more reliably and accurately. In this case, the etching amount can be obtained in real time during the etching process in the release process.

  In particular, in the present embodiment, since the detection structure 13r is also provided on the movable portion 13m of the functional structure 13, it is possible to check the deformation or sticking of the movable portion 13m and to detect the detection structure 13r and the detection structure 13r. By comparing the structural bodies 14r, it is possible to more easily know the inclination posture of the structural bodies 14r for detection.

  In the present embodiment, since the functional structure 13 and the monitor structure 14 are disposed adjacent to each other, the above comparison is easier, but the monitor structure 14 is the functional structure 13. May be arranged at positions separated from each other, and one monitor structure 14 may be provided for a plurality of functional structures 13. These points are the same in the following embodiments.

[Second Embodiment]
Next, a second embodiment relating to a more specific structure of the MEMS element according to the present invention will be described with reference to FIG. FIG. 2 is a plan view (a) and sectional views (b) and (c) of the second embodiment.

  Although this embodiment shows a case where a MEMS vibrator having a cantilevered movable part is configured, the same reference numerals are given to the components corresponding to those of the first embodiment, and description of similar points is omitted.

  As shown in FIGS. 2A and 2B, in this embodiment, a base insulating layer 12A made of a silicon nitride film or the like is formed on the substrate 11, and the MEMS vibrator is formed on the base insulating layer 12A. A functional structure 13 and a monitor structure 14 are formed. The functional structure 13 includes a fixed electrode 13A configured as a lower layer, and a movable electrode 13B including a movable portion 13m facing the fixed electrode 13A from above via a sacrificial layer 12B (gap 13g). The functional structure 13 forms a first conductive layer made of conductive polysilicon or the like similar to the above, and the first conductive layer is patterned to form the fixed electrode 13A and the lower structure of the movable electrode 13B. After a sacrificial layer 12B made of a silicon oxide film or the like is formed thereon, a second conductive layer made of conductive polysilicon or the like is further formed and patterned to form an upper structure of the movable electrode 13B (movable) Part 13m). The portion of the second conductive layer that contacts the lower structure constitutes a support portion 13s of the movable electrode 13B, and the movable portion 13m extends in the horizontal direction from the support portion 13s and extends to above the fixed electrode 13A.

  The monitor structure 14 includes a lower layer 14A formed of the same material as the functional structure 13 and a deformed portion 14m facing the lower layer 14A from above via a sacrificial layer 12B (gap 14g). And an upper layer 14B provided with Here, the lower layer 14A is constituted by a part of the first conductive layer, and the upper layer 14B is constituted by a part of the second conductive layer. A part of the upper layer 14B abuts on the lower layer 14A and is configured as a support portion 14s, and a deformable portion 14m extends horizontally above the gap 14g from the support portion 14s.

  The movable portion 13m has a shape in which the length Ls from the support portion 13s to the outer edge portion (tip portion) is small and the width Ws is large, whereas the deformable portion 14m is formed from the support portion 14s to the outer edge portion (tip end). Part L) 'is large, and the width Ws' is small. Further, the movable portion 13m has a support portion 13s extending along a width Ws that is relatively larger than the length Ls, whereas the deformable portion 14m has a length Ls that is relatively larger than the width Ws ′. It differs in that both sides are open along ′. As a result, the gap between the deformable portion 14m and the lower layer structure with respect to the etching time required to completely remove the sacrificial layer 12B disposed in the gap 13g between the movable portion 13m and the lower layer structure. The etching time required to completely remove the sacrificial layer 12B disposed at 14g is configured to be short.

  In the present embodiment, a plurality of detection structures 13r and 14r are formed on the functional structure 13 and the monitor structure 14, respectively. The detection structures 13r and 14r are the same as in the first embodiment in that the detection structures 13r and 14r are composed of wiring layers, but a plurality of detection structures 13r are formed along the direction of the relatively large width Ws of the functional structure 13. The difference is that a plurality of detection structures 14r are arranged along the direction of the relatively large length Ls ′ of the monitoring structure 14.

  In the present embodiment, as shown in FIG. 2 (c), the sacrificial layer 12B is removed by performing a release process, whereby the deformed portion 14m formed on the gap 14g is bent in the vertical direction from the movable portion 13m. The structure is easy to deform. This is always true regardless of the etching amount in the release process due to the difference between the planar shape of the movable portion 13m and the planar shape of the deformable portion 14m. As a result, the deforming portion 14m causes sticking before the movable portion 13m causes sticking, or is bent downward and deformed. Therefore, the etching amount can be known by confirming the detection structure 14r.

  In the illustrated example, the distal end side of the deforming portion 14m bends and deforms downward, so that the detection structure 14r is also inclined, so that the deformation of the deformation portion 14m can be known by observing the detection structure 14r. Can do. Although the sacrificial layer 12B does not remain below the deformed portion 14m in the illustrated example, the deformed portion 14m is present when the sacrificial layer 12B remains in the vicinity of the support portion 14s of the deformed portion 14m as described above. The structure may be modified so that it can be detected by the detection structure 14r.

  In this case, particularly in the case of the present embodiment, since the plurality of detection structures 14r are arranged along the longitudinal direction in which the etching proceeds below the deformation portion 14m, the number of the detection structures 14r It is also possible to know the magnitude of the etching amount depending on whether or not the inclination is inclined.

  Further, in the present embodiment, the detection structure 13r is configured so that the deformation and sticking of the movable portion 13m can be known. In particular, the plurality of detection structures 13r are arranged along a relatively large width direction. By arranging them, it is configured so that even when a part of the movable portion 13m in the width direction is deformed, this can be easily known.

[Third Embodiment]
Next, a third embodiment according to the present invention will be described with reference to FIG. 3A to 3E are process cross-sectional views (a) to (e) showing a manufacturing process of the third embodiment. In the present embodiment, parts that are the same as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and descriptions of similar parts are omitted.

  In this embodiment, as shown in FIG. 3A, a base insulating film 12A made of a silicon nitride film or the like is formed on a substrate 11, a fixed electrode 13A and a lower layer 14A are formed thereon, and then a sacrificial layer 12B is formed, and further, the movable electrode 13B and the upper layer 14A are formed. The movable electrode 13B has a support portion 13s connected to the base insulating layer 12A through a through-hole formed in the sacrificial layer 12B, and extends horizontally from the support portion 13s and is disposed on the sacrificial layer 12B. A movable portion 13m is provided. The upper layer 14B includes a support portion 14s connected to the lower layer through a through hole formed in the sacrifice layer 12B, and a deformation extending horizontally from the support portion 14s and disposed on the sacrifice layer 12B. 14m is provided. A functional structure 13 constituting a MEMS element is formed by the fixed electrode 13A and the movable electrode 13B, and a monitoring structure 14 is formed by the lower layer 14A and the upper layer 14B.

  Next, as shown in FIG. 3B, the interlayer insulating layer 15 is formed of a silicon oxide film or the like, and a through hole 15 a is formed on the upper layer 14 </ b> B in the interlayer insulating film 15. Then, wiring layers 16A and 16B made of aluminum, an aluminum alloy, or the like are formed on the interlayer insulating film 15. The wiring layer 16B is formed on the upper layer 14B and connected to the upper layer 14B through the through hole 15a.

  Thereafter, as shown in FIG. 3C, an interlayer insulating layer 17 similar to the above is further formed, and a through hole 17a is formed on the wiring layer 16B. Then, wiring layers 18 A and 18 B similar to the above are formed on the interlayer insulating layer 17. Here, the wiring layer 18B is connected to the lower wiring layer 16B through the through hole 17a.

  The wiring layers 16B and 18B formed on the upper layer 14B constitute a detection structure 14r fixed on the monitor structure 14.

  Next, as shown in FIG. 3D, a protective film 19 made of a silicon nitride film, resin, or the like is formed on the interlayer insulating layer 17. Openings 19 a and 19 b are provided in the protective film 19. The opening 19a is provided so as to open a plane range including the functional structure 13, and the opening 19b is provided so as to open a plane range including the monitoring structure 14. Here, the openings 19a and 19b preferably have the same opening shape and opening area. This is because the release etching for the functional structure 13 and the release etching for the monitoring structure 14 can be performed under the same conditions.

  And the release process which etches through opening part 19a, 19b of this protective film 19 is implemented. In this release step, as shown in FIG. 3E, the functional structure 13 is accommodated in a substrate covering structure in which the interlayer insulating layers 15 and 17 and the wiring layers 16A, 16B, 18A, and 18B are laminated. An accommodation recess 13C and an accommodation recess 14C in which the monitor structure 14 is accommodated are formed. Here, after the openings 19a and 19b have the same opening shape and opening area as described above, the housing recesses 13C and 14C have the same opening shape by homogenizing or stirring the etching solution. And an opening area. This is because it can be confirmed that the etching action on the functional structure 13 and the etching action on the monitoring structure 14 are substantially the same.

  At this time, the detection structure 14r constituted by the wiring layers 16B and 18B on the monitor structure 14 is also separated from the substrate covering structure. Further, since the detection structure 14r is configured by the wiring layers 16B and 18B, the upper surface thereof is disposed at substantially the same height level as the upper opening of the housing recess 14C. Therefore, it is possible to easily visually recognize the upper surface of the detection structure 14r even though the monitor structure 14 is disposed in the housing recess 14C of the substrate covering structure.

  Also in the present embodiment, as in the first and second embodiments, the deformable portion 14m formed on the gap 14g is more easily bent and deformed in the vertical direction than the movable portion 13m formed on the gap 13g. Is done. Then, when the deforming portion 14m is bent downward and deformed, or sticking occurs, the posture of the detection structure 14r changes and assumes an inclined posture as illustrated. This inclined posture can be confirmed by visually recognizing the upper surface of the detection structure 14r, and can also be known by detecting the reflection direction by optical means.

  In this embodiment, since the functional structure 13 and the monitor structure 14 are accommodated in the accommodating recesses 13C and 14C provided in the substrate covering structure, respectively, the movable part 13m of the functional structure 13 and the monitor structure are left as they are. Although it is difficult to visually recognize the deformation of the 14 deformation portions 14m, in this embodiment, the detection structure 14r is constituted by the wiring layers 16B and 18B constituting the substrate covering structure, and thus the upper surface of the detection structure 14r. Is disposed at a position close to the upper opening of the accommodating recess 14C, it is possible to easily know the deformation of the deformation portion 14m.

  In the present embodiment, the detection structure 14r is formed only on the monitor structure 14, but in the same manner, the detection structure 13r (not shown) is also formed on the functional structure 13 by the wiring layer. May be. In this case, the presence or absence of deformation of the movable portion 13m can be easily confirmed. However, since the weight of the detection structure 13r (not shown) is added to the functional structure 13, it is necessary to design the functional structure 13 in consideration of this.

[Fourth Embodiment]
Next, a fourth embodiment according to the present invention will be described with reference to FIG. 4A to 4E are process cross-sectional views (a) to (e) showing the manufacturing process of the fourth embodiment. In the present embodiment, parts that are the same as those in the third embodiment are given the same reference numerals, and descriptions of similar parts are omitted.

  In this embodiment, as shown in FIGS. 4A and 4B, a functional structure 13 and a monitor structure 14 are formed as in the third embodiment, and an interlayer insulating film is further formed thereon. 15 and 17 and wiring layers 16A and 16B are formed. However, after that, as the uppermost wiring layer, as shown in FIG. 4B, a wiring layer 18A ′ formed together with the wiring layer 18A is formed above the functional structure 13, and the wiring layer 18A ′. Is formed with pores 18a. In addition, the pores 18b are also formed in the wiring layer 18B ′ formed above the monitor structure 14.

  Thereafter, as shown in FIG. 4C, a protective film 19 having openings 19a and 19b similar to those of the third embodiment is formed, and a release process is performed through the openings 19a and 19b. At this time, in the present embodiment, since the wiring layers 18A 'and 18B' are formed in the opening range of the openings 19a and 19b, etching is performed through the pores 18a and 18b. Here, it is the same as in the third embodiment that the openings 19a and 19b preferably have the same opening shape and opening area.

  At this time, the wiring layer 18A ′ is formed in a wider range than the opening 19a, and is configured so that the wiring layer 18A ′ is not separated from the substrate covering structure even by release etching. On the other hand, the wiring layer 18B ′ is formed within the range of the opening 19b, and is configured such that the wiring layer 18B ′ is separated from the substrate covering structure by release etching. However, there is an opening between the opening ratio (opening area) of the etching opening by the pore 18 a of the wiring layer 18 A ′ and the outer edge of the pore 18 b and wiring layer 18 B ′ of the wiring layer 18 B ′ and the inner edge of the protective film 19. In this case, it is preferable that the aperture ratio (opening area) including the aperture be the same. This is because the etching conditions during release etching can be made common.

  When the release process is performed, the housing recesses 13C and 14C are formed as shown in FIG. The housing recess 13C is formed below the remaining wiring layer 18A ', and the housing recess 14C is formed so as to separate the detection structure 14r formed on the deformation portion 14m from the substrate covering structure.

  At this time, since the functional structure 13 accommodated in the accommodating recess 13C is disposed below the wiring layer 18A ', it is not easy to check the release state, but the monitor accommodated in the accommodating recess 14C. As for the structural body 14, the deformation state of the deformation portion 14m can be easily confirmed by visually recognizing the upper surface of the detection structural body 14r. At this time, since the upper surface of the detection structure 14r is composed of the wiring layer 18B ', it is disposed at the same height as the wiring layer 18A', so there is no problem in confirming the posture of the detection structure 14r. Absent.

  Thereafter, as shown in FIG. 4E, the pores of the wiring layer 18A ′ are formed by a method such as forming a metal film by a sputtering method, a CVD method or the like, or applying a resin material by a coating method or the like. A sealing layer 20A that closes 18a is formed. As a result, the accommodation recess 13C that accommodates the functional structure 13 can be closed, so that the interior of the accommodation recess 13C can be depressurized to place the functional structure 13 under reduced pressure, or a gas such as nitrogen gas can be placed in the accommodation recess 13C. Or the entry of dust, moisture, etc. from the outside can be prevented. This is particularly effective in that water and dust can be prevented from entering the housing recess when a substrate dicing step is performed after the above step to divide the substrate by dicing.

  In this step, the sealing recess 20C can be closed by forming the sealing layer 20B in the opening of the receiving recess 14C as shown. As a result, the upper portion of the detection structure 14r can be fixed by the sealing layer 20B, and the detection structure 14r can be separated from the substrate so as not to become dust in subsequent processes or after the product. .

  Note that the electronic device of the present invention is not limited to the illustrated examples described above, and it is needless to say that various modifications can be made without departing from the scope of the present invention. For example, by forming a plurality of monitor structures 14 having different shapes and providing a detection structure 14r thereto, the release state of the functional structure 13 can be confirmed more precisely. Also good.

Process sectional drawing (a) thru | or (e) of 1st Embodiment. The top view (a) and process sectional drawing (b) and (c) of 2nd Embodiment. Process sectional drawing (a) thru | or (e) of 3rd Embodiment. Process sectional drawing (a) thru | or (e) of 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electronic device, 11 ... Board | substrate, 12 ... Insulating layer, 12A ... Base insulating layer, 12B ... Sacrificial layer, 13 ... Functional structure, 13A ... Fixed electrode, 13B ... Movable electrode, 13a ... Support part, 13m ... Movable part , 13g ... gap, 13r, 14r ... detection structure, 14 ... monitor structure, 14a ... support part, 14m ... deformation part, 14g ... gap, 15, 17 ... interlayer insulation layer, 16A, 16B, 18A, 18B , 18A ', 18B' ... wiring layer, 19 ... protective layer, 19a, 19b ... opening, 20A, 20B ... sealing layer

Claims (11)

A substrate,
A functional structure formed on the substrate and provided with a movable portion having a gap below;
A structure for a monitor including a deforming portion that is formed of the same layer as the movable portion on the substrate and has a gap below and is more easily deformed in the vertical direction than the movable portion due to its planar shape;
A detection structure fixed on the deformable portion and taking a posture according to the deformed state of the deformable portion;
An electronic device comprising:   The electronic device according to claim 1, wherein a flat light reflecting surface is provided on an upper surface of the detection structure.   The apparatus further comprises a substrate covering structure in which one or a plurality of insulating layers and wiring layers are laminated on the substrate, and the substrate covering structure has a function accommodating recess for accommodating the functional structure and the monitor structure. The electronic device according to claim 1, further comprising a monitor housing recess for housing the body.   The electronic device according to claim 3, wherein the functional housing recess and the monitor housing recess have the same opening shape and opening area.   A first coating layer having pores covering the functional housing recess and a second coating layer closing the pores; and the detection structure is provided with an upper layer having pores. The electronic device according to claim 3, wherein the electronic device is provided.   The electronic device according to claim 1, wherein the detection structure is in an inclined posture by the deformation of the deformation portion.   7. The deformation part according to claim 1, wherein a length from the support part to the tip part or between the support parts is larger than the movable part, and a width along the support part is small. An electronic device according to claim 1. A functional structure provided with a movable portion on which a sacrificial layer is disposed below the substrate, and the same layer as the movable portion. The sacrificial layer is disposed below and the planar shape of the functional structure is lower than the movable portion. A structure forming step for forming a monitor structure including a deformable portion configured to be easily deformable, and a detection structure fixed on the deformable portion and taking a posture corresponding to the deformed state of the deformable portion; ,
A release step of forming a gap below each of the movable portion and the deformable portion by etching the sacrificial layer;
An inspection step for confirming the posture of the structure for detection after the release step;
A method for manufacturing an electronic device, comprising: In the structure forming step, a flat light reflecting surface is provided on the upper surface of the detection structure,
9. The method of manufacturing an electronic device according to claim 8, wherein the light reflection state of the light reflecting surface is confirmed in the inspection step. The structure forming step includes a lower formation step for forming the functional structure and the monitoring structure, and one or more insulating layers and wiring layers are stacked on the functional structure and the monitoring structure. An upper forming step of providing a substrate covering structure in which the detection structure is constituted by one or a plurality of wiring layers,
In the release step, a portion of the insulating layer on the functional structure and a portion of the insulating layer on the monitoring structure are removed together with the sacrificial layer, so that the functional structure is removed from the substrate covering structure. A body is separated and a functional housing recess for housing the functional structure is provided, and the monitor structure and the detection structure are separated from the substrate covering structure, and the monitor structure and the detection structure The method for manufacturing an electronic device according to claim 8, wherein a receiving recess for monitoring in which the structure is received is provided. In the upper formation step, a first coating layer having pores is formed above the functional structure, and at the same time, an upper layer having pores of the inspection structure is formed above the monitoring structure. And
In the release step, etching is performed through the pores of the first coating layer and the upper layer,
The method of manufacturing an electronic device according to claim 10, wherein a second coating layer that closes the pores of the first coating layer is formed after the releasing step.

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