JP2010000556A - Integrated micro electromechanical system and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing technique providing a smaller and higher density integrated MEMS (Micro Electro Mechanical System) in integrated MEMS manufacturing technology for integrating a semiconductor integrated circuit and MEMS. <P>SOLUTION: The MEMS is formed on an integrated circuit that processes a MEMS sensor signal. The MEMS has an intermediate moving part 120 comprising a weight 121, a beam 122, and a surrounding void 123, the intermediate moving part being formed by etching of an upper side sacrifice layer 130 and a lower side sacrifice layer 110. The outermost hole of etching holes 141 (micro pores) contributing to forming an upper side void 131 is positioned on an inner side than the outermost hole of etching holes 124 or a void 123 contributing to forming a lower side void 111. The difference between the etching areas of the upper sacrifice layer and the lower side sacrifice layer is thereby made smaller, enabling to enhance etching accuracy and providing a downsizing and higher density. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a microelectromechanical system and a manufacturing technique thereof, and more particularly to a technique effective when applied to an integrated microelectromechanical system in which a semiconductor integrated circuit and a MEMS (MEMS: Micro Electro Mechanical Systems) are integrated. is there.

  Various sensors that detect physical quantities such as acceleration, angular velocity, pressure, etc. using micro electro mechanical systems (MEMS) technology are widely used for camera shake prevention of digital cameras, automobile engine control and tire pressure monitoring. It is used. Furthermore, in recent years, it has come to be applied to game machines, mobile phones, multifunctional wristwatches, and the like, and it is desired to reduce the size, cost, and functionality of MEMS sensors.

The integrated MEMS sensor is a technique for realizing miniaturization by integrating the MEMS sensor and the signal processing semiconductor circuit on one chip, thereby eliminating the wiring between the sensor and the circuit. In general, a method in which a sensor and a circuit are arranged side by side on a semiconductor chip is generally used. However, there is known a method in which a chip can be further downsized by stacking sensors on a circuit (Patent Document 1, Patent). Reference 2).
In Patent Document 1, a pressure sensor is formed by utilizing two wiring layers in an upper layer portion of a circuit. Patent Document 2 is a technique for sealing an acceleration sensor, an angular velocity sensor, and a switch with the uppermost wiring layer using the wiring layer 3 layer in the upper layer part of the circuit as a movable part. is there.

JP 2006-126182 A JP 2006-263902 A

  However, the process for forming the MEMS having the three-layer structure of the wiring layer described in Patent Document 2 into a shape as designed is difficult. In order to explain this, hereinafter, the first wiring layer from the bottom (substrate side) of the three-layer structure is referred to as M1 layer, the second layer (movable part) is referred to as M2 layer, and the third layer is referred to as M3 layer. To do.

In order to make the M2 layer a movable part, it is necessary to remove the sacrificial layer 1 between the M1 layer and the M2 layer and the sacrificial layer 2 between the M2 layer and the M3 layer.
The first conceivable is to take the procedure of removing the sacrificial layer 1 and then laminating the sacrificial layer 2 and the M3 layer. However, since the M2 layer is a movable part, it is difficult to adopt such a procedure. This is because the M2 layer has many shapes like a beam, that is, a shape that requires a space around it. Even if the sacrificial layer 2 and the M3 layer are stacked on the M2 layer, the space around the beam is filled. This is because it cannot be returned, and as a result, it is extremely difficult to form the M3 layer in the shape as designed.

Therefore, as disclosed in Patent Document 2, planar shapes such as a movable portion, a support portion, and a wiring portion are formed in advance in the M2 layer, and at the same time, etching holes are provided in necessary portions while leaving the lower sacrificial layer 1 left. In this state, the sacrificial layer 2 and the M3 layer are further laminated thereon. Thereafter, it is necessary to take a method of simultaneously removing the sacrificial layer 1 through the sacrificial layer 2 through the etch hole of the M3 layer, and further through the space and gap around the structure such as the etch hole of the M2 layer and the beam of the M2 layer. is there.
However, in the method of simultaneously removing the sacrificial layer 1 and the sacrificial layer 2 by the single etching process described above, the sacrificial layer 2 is longer in contact with the etchant and the sacrificial layer 1 is shorter. This is because the etchant cannot reach the etch hole or void in the M2 layer unless the etchant first removes the sacrificial layer 2 through the etch hole in the M3 layer.

That is, in order to form a cavity necessary for the movable part (M2 layer) having a predetermined size, it is necessary to remove the sacrificial layer 1 (corresponding to the lower side of the M2 layer) having a predetermined area by etching. At this time, it is inevitable that the removal area of the sacrificial layer 2 (corresponding to the upper side of the M2 layer) becomes larger.
In order to completely release the movable part (M2 layer), it is preferable to etch the sacrificial layer 1 slightly overly, and to determine the etching time according to the slowest part of the in-plane distribution of the etching rate. As a result, etching progresses to the support part that should be fixed originally, the boundary area with the adjacent MEMS structure, the integrated circuit area, etc., and the support part is peeled off or the structure is damaged. As a result, the yield of the MEMS portion and the damage of the circuit portion are easily caused.

Therefore, conventionally, it has been necessary to secure an etching margin, for example, by increasing the size of the support portion so that the support portion does not peel off, or by increasing the area of the boundary region with the adjacent MEMS structure or peripheral circuit. It was.
For example, when an attempt is made to form a MEMS structure movable part of about 20 μm square in the M2 layer and the etching time is longest such that no etching hole is provided in the M2 layer movable part, the lower part of the 20 μm square MEMS structure is formed. While removing the sacrificial layer 1, side etching of about 14 μm proceeds at both ends of the upper sacrificial layer 2, and when the release of the movable portion of the M2 layer is completed, the cavity region of the sacrificial layer 2 becomes nearly 50 μm square. Even if the area margin with the adjacent part is not taken, a 50 μm square area is required for the 20 μm square MEMS structure movable part. At this time, the area of the entire MEMS structure is more than six times that of the movable part. It also becomes. Actually, by providing an etching hole in the movable part of the M2 layer, it does not increase so far, but in the conventional method, the cavity area of the sacrificial layer 2 increases due to the etching time difference between the sacrificial layer 1 and the sacrificial layer 2 Therefore, it was difficult to prevent the size of the entire area of the MEMS from being enlarged.

  In the surface MEMS type sensor as described in Patent Document 2, since the thickness of the movable part is about 1 μm and thin, the capacitance change amount of the MEMS structure alone is small. Therefore, there are many cases where the capacitance change amount cannot be detected unless the MEMS structures are arranged adjacently and electrically connected in parallel to increase the capacitance change amount ΔC and increase the S / N. As described above, the fact that the accompanying non-movable MEMS region is larger than the movable part main body not only increases the element size but also increases the distance to the adjacent MEMS structure. As a result, the element sensitivity (ΔC / C0) is also lowered due to the addition of the electrical wiring portion to the fixed capacitor C0.

This problem is contrary to the original direction of achieving miniaturization, cost reduction, and high functionality by integrating the MEMS sensor and the sensor semiconductor circuit, and may reduce the merit of integration.
An object of the present invention is to overcome the above-described problems in forming a semiconductor circuit integrated MEMS using three wiring layers of LSI and having a second wiring layer as a movable portion, and to prevent unstructured and damaged MEMS structures. An object is to provide a semiconductor circuit integrated MEMS structure and a manufacturing process which can be easily reduced in size while preventing.

  Another object of the present invention is to overcome the same problem in a semiconductor circuit integrated MEMS in which MEMS structures having different structures are simultaneously formed and formed using three wiring layers and two wiring layers of LSI. Another object of the present invention is to provide a semiconductor circuit integrated MEMS structure and a manufacturing process that can be easily reduced in size while preventing unstructured and damaged MEMS structures.

  In the present invention, in order to solve the above-described problem, the position of the outermost etch hole of the M3 layer is determined in a semiconductor circuit integrated MEMS using three wiring layers of LSI and having the second wiring layer as a movable part. In the M2 layer, there is provided a MEMS structure characterized in that it is arranged on the inner side of the position of the outermost part of the etch holes or voids that contribute to the formation of the cavity below the movable part structure.

  In the present invention, the number of etch holes per area of the M3 layer above the movable portion having a large area such as a weight of the M2 layer is larger than the average number of etch holes per area of the entire M3 layer. A MEMS structure is provided.

In the present invention, the position center of each etch hole in the M3 layer above the movable part having a large area such as the weight of the M2 layer is the position center of each etch hole provided in the movable part having a large area such as the weight in the M2 layer. A MEMS structure characterized in that is provided.
Further, in the present invention, in a semiconductor circuit integrated MEMS in which MEMS structures having different structures are simultaneously formed using three LSI wiring layers and two wiring layers, an etching hole in the MEMS portion using the two wiring layers is formed. Is provided sufficiently inside, and a MEMS structure is provided.

  While the etching of the sacrificial layer 1 (corresponding to the lower side of the M2 layer) that is difficult to etch proceeds favorably, the difference in etching area between the sacrificial layer 1 and the sacrificial layer 2 (corresponding to the upper side of the M2 layer) can be reduced. Make the position control good. For this reason, the movable part in the MEMS structure can be surely formed, and at the same time, the MEMS structures and the signal processing integrated circuit of the MEMS structure can be brought close to each other, and the element size can be reduced. The reduction in device size corresponds to an increase in yield per wafer, which leads to cost reduction and contributes to cost reduction. At the same time, since the distance between adjacent MEMS structures can be reduced, the electric wiring capacity between adjacent MEMS structures can be reduced, and the element sensitivity (ΔC / C0) can be improved.

  As another effect, the difference in etching completion time of each sacrificial layer of a plurality of MEMS structures having different layer structures is reduced, and the controllability of the cavity end position is improved. Thereby, the element size can be reduced, and the same effect as described above can be obtained.

  In the following examples, where necessary, the description will be divided into sections or examples, but unless otherwise specified, they are not independent of each other, one being a variation of some or all of the other It is related to examples, details, and supplementary explanations.

  Also, in the following examples, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), unless otherwise specified, or in principle limited to a specific number in principle. It is not limited to the specific number, and may be a specific number or more.

  Furthermore, in the following embodiments, the constituent elements (including element steps and the like) are not necessarily essential unless otherwise specified or apparent in principle.

Similarly, in the following embodiments, when referring to the shape of a component or the like, it is substantially approximated to the shape or the like, unless otherwise specified or in principle not clearly considered otherwise. Including similar ones. The same applies to the numerical values and ranges.
In all the drawings for explaining the embodiments, the same members are denoted by the same reference numerals in principle, and the repeated explanation thereof is omitted.

In the following embodiments, an example in which a semiconductor integrated circuit (LSI) is formed on a silicon (Si) substrate and then a MEMS is formed on the upper layer will be described. However, the same substrate is formed after the MEMS is formed on the silicon substrate. This method can be applied to the case where the effects of the present invention can be obtained even when an LSI is manufactured on top of each other, when a MEMS is formed at the same time as the manufacturing of the LSI, or when only the MEMS structure is manufactured without being integrated with the LSI. is there.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Example 1>
Examples of an integrated microelectromechanical system in which micromachines and a semiconductor integrated circuit device according to the present invention are formed on a semiconductor substrate are shown in FIGS. 1 to 6A-D.

In the first embodiment, an integrated microelectromechanical system in which a MEMS single-axis inertial sensor and a signal processing semiconductor integrated circuit device of the sensor according to the present invention are formed on a semiconductor substrate will be described.
First, the manufacturing process of the MEMS single-axis inertial sensor according to the first embodiment will be described with reference to the cross-sectional views shown in FIGS. The MEMS single-axis inertial sensor according to the first embodiment described here has an array shape in which two inertial sensor elements are arranged.

  An integrated circuit 2 for MEMS sensor signal processing was fabricated on a silicon substrate (semiconductor substrate) 1 in accordance with a process for manufacturing a normal CMOS integrated circuit device. The integrated circuit 2 includes a signal processing transistor 10 and a contact hole 11 of the MEMS single-axis inertial sensor, a first layer wiring 12, a second layer wiring, and a third layer wiring (the second layer wiring and the third layer wiring are not shown). , A multilayer wiring layer composed of the fourth layer wiring 13, an interlayer insulating film 14 whose upper surface is flattened, a predetermined via hole 15 connected to the MEMS single-axis inertial sensor, and the like.

Subsequently, a lower electrode (M1) 100 of the MEMS inertial sensor portion was formed on the upper portion by a process of manufacturing a CMOS integrated circuit device (FIG. 1). At this time, a part of the lower electrode layer was electrically connected to the fourth layer wiring 13 of the lower integrated circuit 2 as a wiring.
Next, after the lower sacrificial layer (sacrificial layer 1) 110 is formed of an interlayer insulating film, the intermediate movable layer (M2) 120 including the weight 121 of the MEMS inertial sensor, the beam 122 serving as a wiring, and the surrounding gap 123 is provided. Was made. At this time, an etching hole 124 was provided in a necessary portion of the intermediate movable layer, and electrical connection with the lower wiring layer was also formed. Further, an upper sacrificial layer (sacrificial layer 2) 130 was formed using an interlayer insulating film so as to cover the intermediate movable layer 120, and the upper part was planarized using a CMP method or the like (FIG. 2).

Subsequently, an upper electrode layer (M3) 140 having an etching hole 141 for forming a cavity was formed (FIG. 3). At this time, according to the present invention, the outermost peripheral position of the etching hole 141 of the upper electrode layer (M3) 140 is arranged inside the etching hole 124 or the gap 123 at the outermost peripheral position of the intermediate movable layer (M2) 120. Also, electrical connection with the lower wiring layer was formed.
Next, an etchant is introduced through the etching holes 141 and 124 and the air gap 123, and the movable weight 121 of the intermediate movable layer 120 and a part of the upper sacrificial layer 130 and the lower sacrificial layer 110 around the elastic beam 122 are removed by etching. Thus, the cavities 131 and 111 were formed (FIG. 4). At this time, the lower electrode 100 stops etching without progressing downward.
Thereafter, the etching hole 141 of the upper electrode for forming the cavity is closed with the insulating film 142 to seal the cavities 131 and 111, and then the necessary part of the upper electrode (M3) 140 is patterned simultaneously with the insulating film 142. Thus, the MEMS single-axis inertial sensor portion 3 was completed. Finally, an external electrical portion 4 was formed, and finally the cross-sectional shape shown in FIG. 5 was obtained.
In FIG. 5, the weight 121 of the intermediate movable layer 120 is supported by the elastic beam 122 and is movable in the vertical direction of the cross-sectional view, and the capacitance value of the upper electrode 140 or the lower electrode 100 and the intermediate movable layer 120 at that time Can be used as an inertial sensor.
FIGS. 6A to 6D are schematic views showing a planar arrangement of patterns in each constituent layer of the MEMS single-axis inertial sensor of the integrated microelectromechanical system shown in FIG. 6A is a lower electrode layer (M1), FIG. 6B is an intermediate movable layer (M2), FIG. 6C is an upper electrode layer (M3), and FIG. 6D is a schematic plan view of the sacrificial layer 1 or sacrificial layer 2.

As shown in FIG. 6B, the intermediate movable layer 120 is composed of a movable weight 121 portion having a large area in plan and an elastically deformed beam 122 having a relatively large gap 123 portion adjacent thereto. As shown in FIG. 6B, in the weight 121 portion, a large number of etching holes 124 for etching the sacrificial layer on the lower side of the weight at the time of fabrication are arranged near the center of the weight, while there are many gaps 123 around the periphery. Etching holes were not provided in the beam 122 portion.
Further, in the upper electrode layer 140, according to the present invention, a large number of etching holes 141 are densely provided on the upper part of the weight 121 of the intermediate movable layer 120, while the upper part of the beam 122 of the intermediate movable layer 120 is an etching hole. 141 was sparsely arranged. In one example of the first embodiment, when the inertial sensor 1 element is manufactured at 90 μm, the number of etch holes in the dense portion is 9/10 μm square, while in the sparse part, the number is equivalent to 16/30 μm square. did.

With such an arrangement, the etching of the sacrificial layer 1 that proceeds after the sacrificial layer 2 is removed is maintained at the same speed as the lower part of the weight 121 and the lower part of the vicinity of the beam 122 having many voids 123 while maintaining the upper sacrificial layer 2. This can be done while suppressing the lateral extension of the etching end position in the horizontal direction.
At this time, the central position of the etching hole 141 of the upper electrode layer 140 arranged on the upper part of the weight 121 of the intermediate movable layer 120 is matched with the central position of the etching hole 124 provided in the weight 121 as much as possible. As a result, the distance from the etching hole 141 of the upper electrode layer 140 to the etching hole 124 of the weight 121 and the lowermost portion of the sacrificial layer 1 (110) immediately below it becomes the shortest, and the etching of the sacrificial layer 1 immediately below the weight 121 is the earliest. It is possible to proceed.

  By arranging the etching holes 124 and 141 and the gap 123 in this manner, the etching of the sacrificial layer portion below the weight 121 of the intermediate movable layer can be uniformly advanced while minimizing the influence of the shape of the intermediate movable layer 120. I was able to.

  Further, after the etching process time required to completely remove the sacrificial layer portion below the weight 121 of the intermediate movable layer, the time during which the sacrificial layer 2 (130) is exposed to the etchant is the same as that for the sacrificial layer 1 (110). Despite being about 2.5 times the process time exposed to the etchant, the area of the cavity 111 of the sacrificial layer 1 (111) between the lower electrode 100 and the intermediate movable layer 120, the intermediate movable layer 120, As shown in FIG. 6D, the area of the cavity 131 of the sacrificial layer 2 (130) between the upper electrode 140 and the upper electrode 140 could be controlled to be substantially the same. That is, as shown in FIG. 5, the end portions of the upper cavity portion 131 and the lower cavity portion 111 could be formed at substantially the same position.

  As described above, since the two upper and lower cavity layers and the end portions thereof can be formed with good controllability, in the first embodiment, each of the two inertial sensor elements can be manufactured within the design value size without an etching area margin. It was. At this time, the area of the MEMS structure region could be reduced to 1/5 to 1/2 as compared with the conventional manufacturing method.

In Example 1, the outermost peripheral position of the etching hole 141 of the upper electrode layer (M3) 140 is disposed inside the etching hole 124 or the gap 123 at the outermost peripheral position of the intermediate movable layer (M2) 120. More preferably, the outermost peripheral position of the etching hole 241 is determined from the position of the cavity end of the desired / designed sacrificial layer 2 by “(film thickness of sacrificial layer 1) + (thickness of intermediate movable layer) + (sacrificial layer 2 Film thickness (when the M3 layer etching hole is directly above the M2 layer etching hole or void)) or (maximum value of the distance between the M3 layer etching hole and the M2 layer etching hole (M3 layer etching hole is the M2 layer etching hole or void) If it is not directly above)))) ”.
In the first embodiment, as shown in FIG. 5, the integrated circuit portion 2 is disposed below the MEMS portion 3, but the integrated circuit portion also operates satisfactorily without causing performance degradation due to the influence of the MEMS portion manufacturing process. I confirmed that.

  In Example 1, tungsten (W) was used as the material for the lower electrode 100 of the MEMS inertial sensor, and tungsten silicide (WSi) was used as the material for the intermediate movable layer 120 and the upper electrode layer 140. An advantage of using these materials is that, for example, when etching to form the cavities 111 and 131, a sufficient etching selectivity with respect to the interlayer insulating film to form the upper and lower sacrificial layers 130 and 110 can be secured. Further, since tungsten silicide (WSi) is a film having a wide stress control range, the weight 121 and the beam 122 of the intermediate movable layer 120 neutral in the cavity and the upper electrode 140 neutral in the upper part of the cavity are formed. This is a point that can sufficiently adjust the stress of the film forming the layer in the tensile direction. Of course, the material is not limited to these, and other materials may be used.

1 to 6A to 6D, an explanation has been given using the case of an array structure in which two movable weights of inertial sensors are connected. However, even when only one sensor part is used, an array of two or more sensors is arranged. Even when a plurality of different types of sensors are integrated, even when the MEMS part is a sensor / movable body other than the inertial sensor, the same effect can be obtained in the present invention.
Further, in the first embodiment, the case of the five-layer structure of the MEMS structure part 3 layers and the cavity part 2 layers has been described. However, even when the number of the MEMS structure parts and the cavity parts is increased, the same effect can be obtained by application. can get. This applies not only to the first embodiment but also to other embodiments.

Next, a modification of the shape of the intermediate movable layer shown in FIGS. 6A to 6D will be described with reference to FIG. In FIG. 7, the structure of the intermediate movable layer 120 is changed to the shape of the intermediate movable layer 150. The intermediate movable layer 130 in the example of FIGS. 6A to 6D has a structure movable in the vertical direction of the cross-sectional view, but the movable weight 151 of the intermediate movable layer 150 in FIG. The inertial sensor is movable in the horizontal direction of FIG. 7 and in the Y direction shown in FIG. In order to detect a change in the capacitance value caused by the movement in the Y direction, a movable capacitance electrode 155 and a detection electrode 156 are additionally installed in the weight 151, but other structures are provided. The manufacturing process is the same as that described with reference to FIGS. 1 to 6A-D, including the gap 153 included in the intermediate movable layer and the etching hole 154 provided in the weight 151. By applying the present invention to the arrangement of the etching holes of the respective constituent layers as in the case of FIGS. 6A to 6D, even if the planar shape is changed as shown in FIG. As in the example described with reference to FIGS. 6A to 6D, a small integrated sensor can be provided.
<Example 2>
In the second embodiment, a description will be given of an example in which MEMS sensors of different types and structures, and in this example, a diaphragm type sensor are manufactured simultaneously with the inertial sensor described in the first embodiment.

FIG. 8 is a cross-sectional view of an integrated microelectromechanical system in which a MEMS shaft inertial sensor, a MEMS diaphragm type sensor, and an integrated circuit device formed in Example 2 are formed on a semiconductor substrate.
The diaphragm type sensor portion 5 includes a lower electrode 220, a sacrificial layer 230 including a cavity 231 directly above, and a movable upper electrode 240 covered with an insulating film on the sacrificial layer 230 from the lower layer side. The upper electrode layer 240 is movable by force, pressure, vibration, etc. from the upper side of the cross-sectional view of FIG. 8, and can be used as a diaphragm type sensor by measuring the change in the capacitance value of the upper and lower electrodes at that time. .

  A manufacturing process of the diaphragm type sensor portion in the second embodiment will be described using symbols in FIG. Note that the structure of the MEMS single-axis inertial sensor and the process of manufacturing the semiconductor integrated circuit device at the same time are the same as those described in the first embodiment, and are therefore omitted here.

First, when the intermediate movable layer 120 of the inertial sensor is formed, the lower electrode 220 of the diaphragm type sensor is formed at the same time. On top of that, a sacrificial layer 230 is formed simultaneously with the upper sacrificial layer 130 of the inertial sensor using an interlayer insulating film. Furthermore, when the upper electrode 140 of the inertial sensor is formed, the upper movable electrode 240 and the etching hole 241 of the diaphragm type sensor are formed at the same time.
Thereafter, when the sacrificial layer of the inertial sensor is removed and the cavity is formed, at the same time, a part of the sacrificial layer 230 of the diaphragm sensor is removed to form the cavity 231. At this time, the cavity forming portion 231 of the diaphragm type sensor is long time until the lower cavity of the lower sacrificial layer 110 of the inertial sensor is completely formed, like the cavity 131 of the upper sacrificial layer 130 of the inertial sensor. Exposed to etchant. Thereafter, the etching hole 241 is sealed with the interlayer insulating film 142 simultaneously with the sealing of the inertial sensor portion.

  FIGS. 9A to 9D are schematic views showing a planar arrangement of patterns in respective layers constituting the diaphragm type sensor of the integrated microelectromechanical system shown in FIG. 9A is a schematic plan view of the lower electrode layer (M2), FIG. 9B is a sacrificial layer, and FIG. 9C is a schematic plan view of the upper electrode layer (M3). According to the present invention, the upper electrode layer 240 of the diaphragm type sensor is sufficiently inward of the cavity layer portion 231 where an etching hole is desired to be formed in accordance with the time when the cavity portions 131 and 111 of the adjacent inertial sensors are formed. It was arranged to absorb the progress of side etching due to long-time etching, and a desired cavity shape as designed was formed.

  At this time, the outermost peripheral position of the etching hole 241 is “(thickness of the sacrificial layer 1) + (thickness of the intermediate movable layer) + (thickness of the sacrificial layer 2) of the inertial sensor portion 3 from the desired / designed cavity end position. Film thickness (when the M3 layer etching hole is directly above the M2 layer etching hole or void)) or (maximum value of the distance between the M3 layer etching hole and the M2 layer etching hole (M3 layer etching hole is the M2 layer etching hole or void) If it is not directly above))) ”is more desirable.

  In addition, the diaphragm type sensor manufactured in Example 2 has good accuracy of the end position control of the diaphragm sensor, so as shown in FIG. Each diaphragm could be formed without breakage, and the sensitivity could be improved by making an array while maintaining the small shape.

  Next, the capacitance detection circuit will be described using the case of the integrated microelectromechanical system shown in FIG.

  FIG. 10 is a block diagram showing a circuit configuration of an integrated circuit (capacitance detection circuit) including a signal processing transistor in the integrated microelectromechanical system of FIG. In FIG. 10, the capacitance detected by the inertial sensor 3 and the diaphragm type sensor 5 is converted into a voltage by the CV conversion circuit 302. The voltage converted by the CV conversion circuit is amplified by the operational amplifier 303 and then digitized by the AD conversion circuit 304. After that, based on the data stored in the nonvolatile memory 305, various corrections such as temperature and amplifier characteristics are performed by the microprocessor 306 and output from the output interface circuit 307.

  In the example of the block diagram of FIG. 10, the case where both the MEMS sensor and the signal processing circuit system are two is shown, but the sensor may be one or three or more regardless of the type, and the processing circuit system These may be provided for each sensor, or all possible systems may be integrated.

It is a schematic diagram which shows the manufacturing process of the integrated micro electro mechanical system containing the inertial sensor in Example 1 of this invention. It is a schematic diagram which shows the manufacturing process of the inertial sensor following FIG. FIG. 3 is a schematic diagram illustrating a manufacturing process of the inertial sensor subsequent to FIG. 2. FIG. 6 is a schematic diagram illustrating a manufacturing process of the inertial sensor subsequent to FIG. 5. 1 is a schematic cross-sectional view of an integrated microelectromechanical system including an inertial sensor according to Example 1 of the present invention. It is a plane schematic diagram of the main structural structure and main layers of an inertial sensor according to the first embodiment of the present invention. It is a plane schematic diagram of the main structural structure and main layers of an inertial sensor according to the first embodiment of the present invention. It is a plane schematic diagram of the main structural structure and main layers of an inertial sensor according to the first embodiment of the present invention. It is a plane schematic diagram of the main structural structure and main layers of an inertial sensor according to the first embodiment of the present invention. FIG. 6 is a schematic plan view of main structural structures and main layers of an inertial sensor having a movable layer shape different from those of FIGS. 6A to 6D according to the first embodiment of the present invention. It is a cross-sectional schematic diagram of an integrated microelectromechanical system including a diaphragm type sensor and an inertial sensor according to Example 2 of the present invention. It is a plane schematic diagram of the main structural structure and main layers of a diaphragm type sensor according to Example 2 of the present invention. It is a plane schematic diagram of the main structural structure and main layers of a diaphragm type sensor according to Example 2 of the present invention. It is a plane schematic diagram of the main structural structure and main layers of a diaphragm type sensor according to Example 2 of the present invention. It is a plane schematic diagram of the main structural structure and main layers of a diaphragm type sensor according to Example 2 of the present invention. It is an example of the circuit block diagram applied to Example 2 of this invention.

Explanation of symbols

1 ... Silicon substrate (semiconductor substrate),
2. Integrated circuit for MEMS sensor signal processing,
3 ... single axis inertial sensor,
4 ... external connection part,
5 ... Diaphragm type sensor,
10: Signal processing transistor,
11 ... Contact hole,
12 ... 1st layer wiring,
13 ... 4th layer wiring,
14 ... interlayer insulating film,
15 ... via hole,
100 ... lower electrode (M1 layer),
110 ... lower sacrificial layer (sacrificial layer 1),
111 ... lower cavity part,
120 ... intermediate movable layer (M2 layer),
121 ... Weight,
122 ... Beam,
123 ... void,
124 ... Etching hole,
130 ... upper sacrificial layer (sacrificial layer 2),
131 ... upper cavity part,
140 ... upper electrode layer (M3 layer),
141 ... Etching hole,
142 ... sealing insulating film,
150 ... intermediate movable layer (M2 layer),
151: weight,
152 ... Beam,
153: voids,
154 ... Etching hole,
155 ... movable capacitive electrode,
156. Detection electrode,
220 ... lower electrode (M2 layer),
230 ... Sacrificial layer,
231 ... hollow part,
240 ... upper electrode (M3 layer),
241 ... Etching hole,
302 ... CV conversion circuit,
303 ... operational amplifier,
304: AD conversion circuit,
305 ... Non-volatile memory,
306: Microprocessor,
307: Output interface circuit.

Claims (9)

An integrated microelectromechanical system in which micromachines and a semiconductor integrated circuit device are mounted on a semiconductor substrate,
The micro machinery is a first structure layer, a second structure layer provided above the first structure layer, the first structure layer, and the second structure layer. And at least one third structure layer provided therebetween,
In the first region of the second structure layer where the micromachines are provided, first pores are provided through the second structure layer;
In the second region of the third structure layer where the micromachines are provided, second pores and a first void pattern are provided through the third structure layer,
The semiconductor substrate through which the first pores provided at the outermost peripheral position of the first region pass through the second pores provided at the outermost peripheral position of the second region or the first gap pattern An integrated microelectromechanical system, wherein the integrated microelectromechanical system is disposed closer to the center of the first region than a virtual line standing in the vertical direction. An integrated microelectromechanical system in which micromachines and a semiconductor integrated circuit device are mounted on a semiconductor substrate,
The micro machinery is a first structure layer, a second structure layer provided above the first structure layer, the first structure layer, and the second structure layer. And at least one third structure layer provided therebetween,
In the first region of the second structure layer where the micromachines are provided, first pores are provided through the second structure layer;
The first region of the third structure layer where the micromachines are provided includes a second pore and a first void pattern that penetrates the third structure layer. Is provided,
The number of pores per area of the first pores located in a region intersecting the second structure layer by extending the outer peripheral line of the structure upward is provided in the entire second structure layer. An integrated microelectromechanical system characterized in that it is larger than the average number of pores per area of the formed pores.   The integrated microelectromechanical system according to claim 1 or 2, wherein a center position of the first pore coincides with a center position of the second pore. An integrated microelectromechanical system in which micromachines and a semiconductor integrated circuit device are mounted on a semiconductor substrate,
The micro machinery is a first structure layer, a second structure layer provided above the first structure layer, the first structure layer, and the second structure layer. A third structure layer provided therebetween,
In the first region of the second structure layer where the micromachines are provided, first pores are provided through the second structure layer;
A cavity is provided in contact with the lower side of the region where the first pores of the second structure layer are provided;
The distance from the position of the first pore disposed on the outermost periphery of the second structure layer to the imaginary line perpendicular to the semiconductor substrate and the upper end of the cavity is the first The thickness of the third structure layer is added to the distance between the first structure layer and the third structure layer, and the interlayer between the second structure layer and the third structure layer is added. An integrated microelectromechanical system characterized by being larger than the sum of the distances plus the distance.   The integrated microelectromechanical system according to claim 4, wherein the micromachines include one of a metal film and a metal silicon film. A method of manufacturing an integrated microelectromechanical system in which micromachines and a semiconductor integrated circuit device are mounted on a semiconductor substrate,
Forming a semiconductor integrated circuit device on the semiconductor substrate;
Forming a first structure layer on the semiconductor substrate;
Forming a first insulating film on the first structure layer, and further forming a second structure layer on the first insulating film;
Forming a first etching hole and a first gap pattern in a first region of the second structure layer where the micromachines are provided;
Forming a second insulating film on the second structure layer;
Forming a third structure layer on the second insulating film;
Forming a second etching hole in a second region of the third structure layer where the micromachines are provided;
Etching the second insulating film with an etchant that has passed through the second etching hole to form a first cavity below the second region;
The second insulating film deposited in the first etching hole and the first gap pattern is etched, and then the first etching hole and the etchant that has passed through the first gap pattern are used for the first etching. Etching an insulating film to form a second cavity below the first region, and
The semiconductor substrate through which the second etching hole provided at the outermost peripheral position of the second region passes through the first etching hole provided at the outermost peripheral position of the first region or the first gap pattern A method of manufacturing an integrated microelectromechanical system, wherein the integrated microelectromechanical system is disposed closer to the center of the second region than a virtual line standing in the vertical direction.   The integration according to claim 6, wherein tungsten (W) is used for the first structure layer, and tungsten silicide (WSi) is used for the second and third structure layers. A method for manufacturing a microelectromechanical system. A method of manufacturing an integrated microelectromechanical system in which micromachines and a semiconductor integrated circuit device are mounted on a semiconductor substrate,
Forming a semiconductor integrated circuit device on the semiconductor substrate;
Forming a first structure layer on the semiconductor substrate;
Forming a first insulating film on the first structure layer, and further forming a second structure layer on the first insulating film;
Forming a first etching hole and a first gap pattern in a first region of the second structure layer where the micromachines are provided;
Forming a second insulating film on the second structure layer;
Forming a third structure layer on the second insulating film;
Forming a second etching hole in a second region of the third structure layer where the micromachines are provided;
Etching the second insulating film with an etchant that has passed through the second etching hole to form a first cavity below the second region;
The second insulating film deposited in the first etching hole and the first gap pattern is etched, and then the first etching hole and the etchant that has passed through the first gap pattern are used for the first etching. Etching an insulating film to form a second cavity below the first region, and
The number of pores per area of the first pores located in a region where the outer peripheral line of the second region extends upward and intersects with the third structure layer is the entire third structure layer A method for producing an integrated microelectromechanical system, wherein the average number of pores per area of the pores provided in is larger.   9. The integration according to claim 8, wherein tungsten (W) is used for the first structure layer, and tungsten silicide (WSi) is used for the second and third structure layers. A method for manufacturing a microelectromechanical system.

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