MEMS element

Abstract

To provide a MEMS device having good sensitivity and improved AOP.SOLUTION: On a substrate 1 provided with a back chamber 9, a back plate 7 including a fixed electrode 5 and a vibrating membrane 3 including a movable electrode are arranged to face each other, the vibrating membrane 3 is provided with a plurality of vibrating parts 13 and a plurality of columns 10 connected to the back plate 7, column side slits 11, and peripheral edge side slits 12, and the peripheral edge side slits 12 include a third slit part and a fourth slit part extending in a direction along the peripheral edge of the vibrating membrane 3. Wherein the third slit portion and the fourth slit portion each include a plurality of sub-slit portions, the sub-slit portions constituting the third slit portion and the sub-slit portions constituting the fourth slit portion are alternately arranged in a direction along the peripheral edge portion, and ends of the sub-slit portions are arranged so as to overlap each other in a direction from the central portion of the vibration film 3 toward the peripheral edge portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a capacitive MEMS element used as a microphone, various sensors, etc. [Background technology]

[0002] A known MEMS (Micro Electro Mechanical Systems) element that uses semiconductor processes is a capacitive MEMS element in which a backplate including a fixed electrode with multiple acoustic holes and a vibrating membrane including a movable electrode are arranged on a substrate with an insulating film acting as a spacer sandwiched between them.

[0003] A capacitive MEMS element detects the displacement of a movable electrode caused by the vibration of a vibrating membrane as a change in capacitance between the movable electrode and a fixed electrode, and outputs a detection signal. This type of MEMS element is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-55087 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, Figure 15 shows a cross-sectional view of a conventional capacitive MEMS element. As shown in Figure 15, a conventional capacitive MEMS element includes a substrate 31, which serves as a support substrate, on which an insulating film 32 is formed. A vibrating membrane 33, including a conductive movable electrode, is then formed on the insulating film 32. Furthermore, a spacer 34 made of an insulating film and a back plate 37, consisting of a conductive fixed electrode 35 and an insulating film 36, are stacked to form an air gap structure. Reference numeral 38 denotes an acoustic hole formed in the back plate 37, 39 denotes a back chamber formed in the substrate 31, and 40 denotes a slit extending along the periphery of the vibrating membrane 33 and consisting of multiple sub-slits divided in this direction. When sound pressure or the like is applied to such a capacitive MEMS element, the center of the vibrating membrane 33 vibrates significantly. The slits 40 facilitate vibration of the peripheral portion of the vibrating membrane 33, which is bonded to the substrate 31 and the spacer 34. However, the amplitude of the peripheral portion is smaller than that of the central portion.

[0006] Generally, in a capacitive MEMS element, if the spring constant of the diaphragm 33 is reduced to increase sensitivity, the displacement becomes too large, causing the diaphragm 33 to come into contact with the back plate 37. In addition, a difference occurs in the amplitude between the center of the diaphragm 33, where the displacement is large, and the peripheral portion, where the displacement is small. As a result, the area of ​​the diaphragm 33 that displaces parallel to the back plate 37 becomes smaller, causing a problem of deterioration of the AOP (Acoustic Overload Point).

[0007] One way to increase the amplitude of the peripheral edge is to lengthen the length of each sub-slit portion of slit 40 extending in the direction along the peripheral edge. However, forming long sub-slit portions in diaphragm 33, which has a small spring constant, can cause warping of diaphragm 33. When diaphragm 33 warps, the width of each sub-slit increases beyond the desired designed width, resulting in a problem of reduced sensitivity, particularly in the low-frequency range.

[0008] When using this capacitive MEMS element as a microphone, it is necessary to improve the AOP while minimizing the decrease in sensitivity.

[0009] Therefore, an object of the present invention is to provide a MEMS device having good sensitivity and an improved AOP. [Means for solving the problem]

[0010] One embodiment of the MEMS element of the present invention is a MEMS element including a substrate with a back chamber, a diaphragm including a movable electrode bonded onto the substrate, and a back plate including a fixed electrode arranged opposite the movable electrode, wherein the diaphragm has a pillar in its center connecting the back plate and the diaphragm, and has a plurality of vibration parts in an area between a joint between the pillar and the diaphragm and a peripheral edge of the diaphragm, each of the plurality of vibration parts being formed from an area surrounded by a pillar-side slit including a first slit part and a second slit part bonded to each other, and a peripheral edge-side slit, the first slit part and the second slit part extending in mutually different directions from the joint side between the pillar and the diaphragm toward the peripheral edge, and the peripheral edge-side slit extends from the first slit part toward the peripheral edge. The peripheral portion side slit is arranged in the peripheral portion between such an extension line and an extension line from the second slit portion toward the peripheral portion, and the peripheral portion side slit includes a third slit portion that is arranged inside the peripheral portion of the vibration membrane and extends in a direction along the peripheral portion, and a fourth slit portion that is arranged on the pillar side of the third slit portion and extends in a direction along the third slit portion, and the third slit portion and the fourth slit portion are each composed of a plurality of sub-slit portions, and each of the sub-slit portions that make up the third slit portion and each of the sub-slit portions that make up the fourth slit portion are arranged alternately in the direction along the peripheral portion, and the ends of each of the sub-slit portions that make up the third slit portion and each of the sub-slit portions that make up the fourth slit portion are arranged so as to overlap each other in the direction from the central portion toward the peripheral portion. [Effects of the Invention]

[0011] According to the MEMS element of the present invention, the center of the diaphragm is joined to the back plate by a pillar, suppressing the amplitude of the diaphragm's center. Furthermore, by providing slits in the diaphragm, a vibrating portion with minimal difference in amplitude between the center and peripheral portions of the diaphragm can be formed. Multiple such vibrating portions are formed on the diaphragm, resulting in a large overall detection signal. The peripheral slits do not expand beyond the desired designed width, preventing a decrease in sensitivity. Furthermore, by dividing the vibrating portion into multiple small-area vibrating portions, the force applied to each vibrating portion when a bias voltage is applied between the fixed electrode and the movable electrode is reduced, resulting in less distortion of the detection signal. Thus, according to the present invention, it is possible to provide a MEMS element that can improve AOP without reducing sensitivity. As a result, a high-performance MEMS element for a microphone can be obtained. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view schematically illustrating a MEMS element (embodiment 1) according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic plan view illustrating a vibrating membrane portion in the first embodiment. [Figure 3] 4A to 4C are diagrams illustrating vibration characteristics of a vibrating section in the first embodiment. [Figure 4] 4A to 4C are diagrams illustrating vibration characteristics of a vibrating section in the first embodiment. [Figure 5] 4A to 4C are diagrams illustrating vibration characteristics of a vibrating section in the first embodiment. [Figure 6] 4A to 4C are diagrams illustrating vibration characteristics of a vibrating section in the first embodiment. [Figure 7] 4A to 4C are diagrams illustrating vibration characteristics of a vibrating section in the first embodiment. [Figure 8] 4A to 4C are diagrams illustrating vibration characteristics of a vibrating section in the first embodiment. [Figure 9] FIG. 10 is a schematic plan view illustrating a vibrating membrane portion of a MEMS element (embodiment 2) according to another embodiment of the present invention. [Figure 10]FIG. 10 is a schematic plan view illustrating a vibrating membrane portion of a MEMS element (Embodiment 3) according to still another embodiment of the present invention. [Figure 11] FIG. 10 is a schematic plan view illustrating a vibrating membrane portion of a MEMS element (Embodiment 4) according to still another embodiment of the present invention. [Figure 12] 10 is a diagram illustrating the vibration characteristics of a vibrating section in the fourth embodiment. FIG. [Figure 13] FIG. 10 is a cross-sectional view showing a MEMS element (embodiment 5) according to still another embodiment of the present invention. [Figure 14] FIG. 13 is a plan view illustrating a vibration membrane portion in the fifth embodiment. [Figure 15] FIG. 1 is a cross-sectional view of a conventional capacitive MEMS element. DETAILED DESCRIPTION OF THE INVENTION

[0013] Next, embodiments of the MEMS element of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In Figures 1, 2, 9 to 11, 13, and 14, some dimensions are exaggerated for the purpose of explanation, and the dimensional ratios of each member and part are not accurately shown.

[0014] (Embodiment 1) Fig. 1 is a cross-sectional view illustrating a first embodiment of a MEMS element of the present invention. As shown in Fig. 1, one embodiment of a MEMS element 100 of the present invention includes a substrate 1 made of, for example, a silicon substrate as a support substrate, on which an insulating film 2 made of, for example, a thermal oxide film is formed, and a vibrating membrane 3 including a conductive movable electrode made of, for example, polysilicon is formed on the insulating film 2. Furthermore, an insulating spacer 4 made of, for example, a USG (undoped silicate glass) film, and a backplate 7 including a conductive fixed electrode 5 made of, for example, polysilicon and an insulating film 6 made of, for example, silicon nitride are stacked.

[0015] In the MEMS element 100 of this embodiment, the vibrating membrane 3 and the back plate 7 are each joined and connected to a pillar 10, and are provided with a pillar-side slit 11 and a peripheral edge-side slit 12. Reference numeral 8 denotes an acoustic hole formed in the back plate 7, 9 denotes a back chamber formed in the substrate 1, and 13 denotes a vibrating part.

[0016] Fig. 2 is a plan view schematic diagram illustrating the vibration membrane portion of the MEMS element shown in Fig. 1, and is a diagram illustrating the arrangement of pillar 10, pillar-side slits 11A, and peripheral edge-side slits 12A. In Fig. 1, back chamber 9 formed in substrate 1 is circular, and the outer periphery in Fig. 2 corresponds to the outer periphery of back chamber 9 of substrate 1. The cross-sectional schematic diagram shown in Fig. 1 is a cross-sectional view passing through the center of pillar 10, two pillar-side slits 11A facing each other with pillar 10 as the center, and two peripheral edge-side slits 12A facing each other in Fig. 2.

[0017] As shown in Fig. 2, when the portion of the vibrating membrane 3 corresponding to the back chamber 9 is circular, the pillar 10 is arranged on the vibrating membrane 3 so that the center of the vibrating membrane 3 coincides with the center of the circular pillar 10. A plurality of vibrating portions 13A are formed in the region between the joint of the vibrating membrane 3 with the pillar 10 and the peripheral edge of the vibrating membrane 3. Therefore, pillar-side slits 11A and peripheral-edge slits 12A are arranged around the pillar 10. In the present embodiment shown in Fig. 2, an example is shown in which four vibrating portions 13A are formed.

[0018] A detailed description will be given using one vibrating section as an example. In vibrating section 13A formed in the upper right region of pillar 10 of vibrating membrane 3 shown in Fig. 2, pillar-side slit 11A is formed by first slit section 11a and second slit section 11b. First slit section 11a extends upward in the drawing from the pillar 10 side, parallel to the radial direction of vibrating membrane 3. Second slit section 11b extends rightward in the drawing from the pillar 10 side, parallel to the radial direction of vibrating membrane 3, and is joined to first slit section 11a at a joining angle of 90 degrees.

[0019] By forming the pillar-side slit 11A, a part of the diaphragm 3 on the pillar 10 side, whose vibration is restricted by the pillar 10, becomes more likely to vibrate.

[0020] Furthermore, by forming peripheral slits 12A in the peripheral portion of vibrating membrane 3 where it is bonded to substrate 1, insulating film 2, and spacer 4, the peripheral portion of vibrating membrane 3, whose vibration is restricted by bonding to substrate 1, etc., becomes more vibrable. These peripheral slits 12A have the same effect as the slits 40 formed in the general MEMS element described in FIG. 15 . However, in this embodiment, peripheral slits 12A are formed so as to open to or near the intersection of the extension lines of first slit portion 11a and second slit portion 11b, as shown by the two-dot chain lines in FIG. 2, in order to form a single vibrating portion in the area sandwiched between these extension lines. Furthermore, peripheral slits 12A in this embodiment are composed of third slit portion 12a and fourth slit portion 12b.

[0021] As shown in FIG. 2, the third slit portion 12a is disposed inside the peripheral edge of the vibrating membrane 3. The third slit portion 12a is composed of a plurality of sub-slit portions extending in a direction along the peripheral edge of the vibrating membrane 3 (the circumferential direction of the vibrating membrane 3). In the present embodiment shown in FIG. 2, the third slit portion 12a is composed of two sub-slit portions 12a1 and 12a2. The two or more sub-slit portions constituting the third slit portion 12a are arranged in series along the peripheral edge of the vibrating membrane 3 with a gap between them. The fourth slit portion 12b is disposed on the pillar 10 side of the third slit portion 12a. The fourth slit portion 12b is composed of a plurality of sub-slit portions extending in a direction along the third slit portion 12a. In the present embodiment shown in FIG. 2, the fourth slit portion 12b is composed of three sub-slit portions 12b1, 12b2, and 12b3. The two or more sub-slits constituting fourth slit portion 12b are spaced apart and arranged in series along third slit portion 12a. The lengths of the sub-slits constituting third slit portion 12a and fourth slit portion 12b in the extension direction are set to lengths that do not cause warping of vibrating membrane 3 and that do not cause the width of each sub-slit portion to expand beyond the designed desired width.

[0022] 2, the plurality of sub-slit portions constituting third slit portion 12a and the plurality of sub-slit portions constituting fourth slit portion 12b are arranged alternately in a direction along the peripheral edge of vibrating membrane 3. The ends of the sub-slit portions constituting third slit portion 12a and the ends of the sub-slit portions constituting fourth slit portion 12b are arranged so as to overlap each other in a direction (radial direction) from the center of vibrating membrane 3 toward the peripheral edge. By arranging third slit portion 12a and fourth slit portion 12b in this manner, the peripheral edge of the region sandwiched between the extension lines of column-side slits 11A, each indicated by a two-dot chain line in FIG. 2, alternates between portions where either third slit portion 12a or fourth slit portion 12b is arranged and portions where both third slit portion 12a and fourth slit portion 12b are arranged.

[0023] In this way, the area surrounded by the pillar-side slit 11A and the peripheral-side slit 12A becomes one vibrating part 13 A. The multiple vibrating parts 13A are evenly arranged around the center of the pillar 10 (the center of the vibrating membrane 3), resulting in four vibrating parts with uniform characteristics.

[0024] Next, we will explain the vibration characteristics of vibrating part 13A. The vibration characteristics of vibrating part 13A change depending on the material, thickness, and size of vibrating membrane 3. Furthermore, the vibration characteristics can be changed by changing the shapes of pillar-side slits 11A and peripheral-edge-side slits 12A.

[0025] 3 to 8 are diagrams illustrating the vibration characteristics of the vibrating section 13A of the MEMS element of this embodiment. The vertical axis in FIGS. 3 to 7 represents the amplitude, expressed as a relative amount with the largest amplitude being 1.00. The horizontal axis represents the distance from the center of the vibrating membrane 3, and its direction is the radial direction of the vibrating membrane 3, which runs from the center of the pillar 10 through the junction between the first slit portion 11a and the second slit portion 11b of the pillar-side slit 11A. The horizontal axis represents the relative distance, with the center of the pillar 10 being 0.00 and the outer periphery shown in FIG. 2 being 1.00. FIG. 3 compares the amplitude of the vibrating section 13A when the number of sub-slit portions constituting the peripheral-edge-side slit 12A is changed. FIG. 3 compares the vibration characteristics of diaphragm A, in which the third slit portion 12a of the peripheral edge slit 12A is composed of two sub-slit portions and the fourth slit portion 12b is composed of three sub-slit portions, as shown in FIG. 2, with diaphragm B, in which the third slit portion 12a is composed of three sub-slit portions and the fourth slit portion 12b is composed of four sub-slit portions. Here, the ratio of the length of the longest sub-slit portion in the extension direction to the spacing between the sub-slit portions is the same for each of the third slit portion 12a and the fourth slit portion 12b. In other words, as the number of sub-slit portions increases, the length of each sub-slit portion decreases and the spacing between the sub-slit portions also decreases. As the number of sub-slit portions increases, the overlap length between the ends of the sub-slit portions constituting the third slit portion 12a and the fourth slit portion 12b also decreases. All other conditions are the same except for the configuration of the peripheral edge slit 12A.

[0026] As shown in FIG. 3, both diaphragm A and diaphragm B vibrate between the column-side slit 11A and the peripheral-side slit 12A. Furthermore, when the number of sub-slits constituting the peripheral-side slit 12A is small and the length of the sub-slits constituting the peripheral-side slit 12A is long (sub-slit length: diaphragm A > diaphragm B), the amplitude near the peripheral-side slit 12A is large (amplitude: diaphragm A > diaphragm B). When the number of sub-slits constituting the peripheral-side slit 12A is small and the overlap length between the ends of the sub-slits constituting the peripheral-side slit 12A and the ends of the sub-slits constituting the fourth slit 12b is long (overlapping length: diaphragm A > diaphragm B), the amplitude near the peripheral-side slit 12A is large. In the example shown in FIG. 3, the length of the column-side slit 11A in the extension direction is the same for diaphragms A and B. In this case, the amplitude near the column-side slit 11A is largest and is approximately equal.

[0027] FIG. 4 compares the amplitude of vibration of vibrating portion 13A when the number of sub-slits constituting the peripheral edge slit is constant and the length of the sub-slits is varied. As shown in FIG. 2, third slit portion 12a of peripheral edge slit 12A is composed of two sub-slits, and fourth slit portion 12b is composed of three sub-slits. The amplitude of vibration of vibrating portion 13A is compared when the ratio of the length of the longest sub-slit in the extension direction to the spacing between the sub-slits is varied. FIG. 4 compares the vibration characteristics of vibrating membrane A, which has the above ratio of 8:1, vibrating membrane C, which has the above ratio of 7:2, and vibrating membrane D, which has the above ratio of 6:3. Here, the length of the sub-slits in the extension direction of peripheral edge slit 12A is as follows: vibrating membrane A > vibrating membrane C > vibrating membrane D, and the spacing between the sub-slits is as follows: vibrating membrane A < vibrating membrane C < vibrating membrane D. In this case, the overlap length between the end of the sub-slit portion of the third slit portion 12a and the end of the sub-slit portion of the fourth slit portion 12b is as follows: vibrating membrane A > vibrating membrane C > vibrating membrane D. All conditions except for the configuration of the peripheral edge side slit 12A are the same.

[0028] As shown in Figure 4, it can be seen that all of the diaphragms A, C, and D vibrate between the pillar-side slit 11A and the peripheral-side slit 12A. It can also be seen that the longer the sub-slit portion that constitutes the peripheral-side slit 12A, the greater the amplitude near the peripheral-side slit 12A. It can also be seen that the shorter the spacing between the sub-slit portions, the greater the amplitude near the peripheral-side slit 12A. It can also be seen that the longer the overlapping length of the ends of the sub-slit portions, the greater the amplitude near the peripheral-side slit 12A. In the example shown in Figure 4, it can be seen that the amplitude near the pillar-side slit 11A is the largest, and that for diaphragms with the same length in the extension direction of the pillar-side slit 11A, the amplitude near the pillar-side slit 11A is approximately the same.

[0029] Fig. 5 compares the amplitude of vibration part 13A when the length of the pillar-side slit is changed. As shown in Fig. 2, the vibration characteristics of vibrating membrane A, in which third slit part 12a of peripheral edge side slit 12A is composed of two sub-slit parts and fourth slit part 12b is composed of three sub-slit parts, and the length of pillar-side slit 11A is a predetermined length, are compared with those of vibrating membranes E and F, in which the lengths of pillar-side slit 11A of vibrating membrane A are 73% and 39%, respectively.

[0030] As shown in Figure 5, it can be seen that all of the diaphragms A, E, and F vibrate between the pillar-side slits 11A and the peripheral-side slits 12A. It can also be seen that the longer the pillar-side slits 11A, the larger the amplitude near the pillar-side slits 11A. For diaphragms with the same configuration of the peripheral-side slits 12A, the amplitude near the peripheral-side slits 12A is approximately the same.

[0031] The vibration characteristics of the vibrating section 13A can be adjusted appropriately by changing the configuration of the peripheral edge slits 12A as described in Figures 3 and 4 and / or by changing the extension length of the pillar side slits 11A as described in Figure 5. Figure 6 compares the amplitude of the vibrating section 13A when both the configuration of the peripheral edge slits 12A and the configuration of the pillar side slits 11A are changed. As an example, the vibration characteristics can be adjusted by changing the length of the sub-slits that make up the peripheral edge slits and the length of the pillar side slits. The length of the peripheral edge slits is as follows: vibrating membrane X > vibrating membrane Y > vibrating membrane Z. The length of the pillar side slits 11A is as follows: vibrating membrane X < vibrating membrane Y < vibrating membrane Z.

[0032] As shown in FIG. 6, it can be seen that all of the vibrating membranes X to Z vibrate between the pillar-side slits 11A and the peripheral-side slits 12A. It can also be seen that the vibrating membrane X has vibration characteristics in which the amplitude is largest near the peripheral-side slits 12A and the amplitude is small near the pillar-side slits 11A. It can also be seen that the vibrating membrane Y has vibration characteristics in which the amplitude is largest at the center of the vibrating portion 13A and the amplitude is small near the pillar-side slits 11A and the peripheral-side slits 12A. It can also be seen that the vibrating membrane Z has vibration characteristics in which the amplitude is largest near the pillar-side slits 11A and the amplitude is small near the peripheral-side slits 12A. In this way, by changing the shapes (lengths) of the peripheral-side slits 12A and the pillar-side slits 11A, it is possible to appropriately change the vibration characteristics of the vibrating portion 13A.

[0033] 7 is a diagram illustrating the vibration characteristics of the vibrating part 13A of the MEMS element of this embodiment, which includes the vibrating membrane Y of FIG. 6, in comparison with the vibration characteristics of a conventional MEMS element. The conventional example uses the vibrating membrane 33 of a general MEMS element shown in FIG.

[0034] As shown in Figure 7, in a typical MEMS element shown as a conventional example, the amplitude of vibration is greatest at the center of the diaphragm and decreases toward the periphery. In other words, the area that can be described as the vibrating portion is up to a certain distance from the center, and the area around the periphery does not function as a vibrating portion. In contrast, in a MEMS element having the vibration characteristics of diaphragm Y, the entire diaphragm in the area between pillar-side slit 11A and periphery-side slit 12A vibrates relatively uniformly, functioning as a vibrating portion.

[0035] In this embodiment, the signal output from each vibrating section is small because the vibrating membrane 3 is divided into four vibrating sections 13A as shown in Fig. 2. However, by providing multiple vibrating sections, the area of ​​the vibrating sections that displace in the radial direction of the vibrating membrane 3 almost parallel to the fixed electrode 5 increases as shown in Fig. 7, and therefore sufficiently high sensitivity can be obtained.

[0036] FIG. 8 also shows the change in amplitude when a sound pressure of 130 dB is applied to the diaphragm 3. There is no significant difference in the amplitude of the diaphragm between the MEMS element having the vibration characteristics of the diaphragm Y of this embodiment and the conventional MEMS element. However, comparing the change in amplitude reveals that the MEMS element of this embodiment exhibits symmetrical amplitude. As described above, the MEMS element of this embodiment, in which the diaphragm 3 including the movable electrode displaces approximately parallel to the fixed electrode 5, improves the AOP. Furthermore, if the diaphragm 3 is made of a material with a small spring constant that easily vibrates, the force applied to each vibrating element when a bias voltage is applied between the fixed electrode 5 and the movable electrode is reduced, thereby reducing distortion of the detection signal and improving the AOP. In this embodiment, the provision of the pillars 10 prevents problems such as excessive vibration of the diaphragm 3, even with a diaphragm 3 having a small spring constant. Furthermore, the lengths of the sub-slits constituting the peripheral edge slits 12A are set to lengths that prevent the width of each sub-slit from expanding beyond the desired designed width, thereby suppressing a decrease in sensitivity, particularly in the low-frequency range.

[0037] As shown in Fig. 3 and other figures, the vibration characteristics of the vibrating membrane 3 can be changed as needed to the desired vibration characteristics. Therefore, the vibrating membrane 3 of the MEMS element of the present invention can be configured to include a plurality of vibrating sections with the same vibration characteristics, or can be configured to combine vibrating sections with different vibration characteristics to complement each other. In the latter case, for example, a detection signal can be obtained by combining a vibrating section with vibration characteristics in which the amplitude amount on the pillar side is relatively large and the amplitude amount on the periphery side is relatively small with a vibrating section with vibration characteristics in which the amplitude amount on the pillar side is relatively small and the amplitude amount on the periphery side is relatively large.

[0038] (Embodiment 2) Next, a second embodiment of the MEMS element of the present invention will be described. Fig. 9 corresponds to a plan view schematic diagram illustrating the vibration membrane portion of the MEMS element shown in Fig. 1, and is a diagram illustrating the arrangement of pillars 10, pillar-side slits 11B, and peripheral edge-side slits 12B. In Fig. 1, back chamber 9 formed in substrate 1 is circular, and the outer periphery of Fig. 9 corresponds to the outer periphery of back chamber 9 of substrate 1.

[0039] As shown in Fig. 9, when the portion of the vibrating membrane 3 corresponding to the back chamber 9 is circular, the pillar 10 is arranged on the vibrating membrane 3 so that the center of the vibrating membrane 3 coincides with the center of the circular pillar 10. A plurality of vibrating portions 13B are formed in the region between the joint of the vibrating membrane 3 with the pillar 10 and the peripheral edge of the vibrating membrane 3. Therefore, pillar-side slits 11B and peripheral-edge slits 12B are arranged around the pillar 10. In the present embodiment shown in Fig. 9, an example is shown in which six vibrating portions 13B are formed.

[0040] A detailed description will be given taking one vibrating part as an example. In vibrating part 13B formed in the upper right region of pillar 10 of vibrating membrane 3 shown in Fig. 9, pillar-side slit 11B is formed by first slit part 11c extending from pillar 10 side in the upward direction in the drawing parallel to the radial direction of vibrating membrane 3, and second slit part 11d extending from pillar 10 side in the upper right direction in the drawing parallel to the radial direction of vibrating membrane 3 and joining first slit part 11c at a joining angle of 60 degrees.

[0041] By forming the pillar-side slit 11B, a part of the diaphragm 3 on the pillar 10 side, whose vibration is restricted by the pillar 10, becomes more likely to vibrate.

[0042] Furthermore, by forming peripheral slits 12B in the peripheral portion of vibrating membrane 3 where it is bonded to substrate 1, insulating film 2, and spacer 4, the peripheral portion of vibrating membrane 3, whose vibration is restricted by bonding to substrate 1, etc., becomes more vibrating. These peripheral slits 12B are formed to open to the position where they intersect with or near the extension lines, respectively, shown by the two-dot chain lines in Figure 9, in order to form a single vibrating portion in the area sandwiched between the extension lines of first slit portion 11c and the extension line of second slit 11d. Furthermore, peripheral slits 12B in this embodiment are composed of third slit portion 12c and fourth slit portion 12d.

[0043] As shown in FIG. 9, the third slit portion 12c is disposed inside the peripheral edge of the vibrating membrane 3. The third slit portion 12c is composed of a plurality of sub-slit portions extending in a direction along the peripheral edge of the vibrating membrane 3. In the present embodiment shown in FIG. 9, the third slit portion 12c is composed of two sub-slit portions 12c1 and 12c2. The two or more sub-slit portions constituting the third slit portion 12c are arranged in series along the peripheral edge of the vibrating membrane 3 with a gap between them. The fourth slit portion 12d is disposed on the pillar 10 side of the third slit portion 12c. The fourth slit portion 12d is composed of a plurality of sub-slit portions extending in a direction along the third slit portion 12c. In the present embodiment shown in FIG. 9, the fourth slit portion 12d is composed of three sub-slit portions 12d1, 12d2, and 12d3. The two or more sub-slit portions constituting the fourth slit portion 12d are arranged in series along the third slit portion 12c with a gap between them. The length in the extension direction of each sub-slit portion constituting the third slit portion 12c and the fourth slit portion 12d is set to a length that does not cause warping of the vibration membrane 3 and does not cause the width of each sub-slit portion to expand beyond the designed desired width.

[0044] 9, the plurality of sub-slit portions constituting third slit portion 12c and the plurality of sub-slit portions constituting fourth slit portion 12d are arranged alternately in a direction along the peripheral edge of vibrating membrane 3. The ends of the sub-slit portions constituting third slit portion 12c and the ends of the sub-slit portions constituting fourth slit portion 12d are arranged so as to overlap with each other in a direction from the center of vibrating membrane 3 toward the peripheral edge. By arranging third slit portion 12c and fourth slit portion 12d in this manner, the peripheral edge of the region sandwiched between the extension lines of column-side slits 11B, each indicated by a two-dot chain line in FIG. 9, alternates between portions where either third slit portion 12c or fourth slit portion 12d is arranged and portions where both third slit portion 12c and fourth slit portion 12d are arranged.

[0045] In this way, the area surrounded by the pillar-side slit 11B and the peripheral-side slit 12B becomes one vibrating part 13B. The multiple vibrating parts 13B are evenly arranged around the center of the pillar 10 (the center of the vibrating membrane 3), resulting in six vibrating parts with uniform characteristics.

[0046] The vibration characteristics of the vibrating section 13B of this embodiment show similar trends to those of the vibrating section 13A of the above-described embodiment 1. Specifically, the vibration characteristics of the vibrating section 13B vary depending on the material, thickness, and size of the vibrating membrane 3. Furthermore, the vibration characteristics vary depending on the shapes and arrangements of the pillar-side slits 11B and the periphery-side slits 12B.

[0047] Therefore, like the vibrating section 13A of the first embodiment, the vibrating section 13B of the MEMS element of this embodiment also exhibits vibration characteristics similar to those shown in FIGS. 3 to 8. Comparing the vibrating section of this embodiment with the vibrating section of the first embodiment, the angle (junction angle) at which the first slit section 11c and the second slit section 11d of the column-side slit intersect is smaller. Here, if the lengths of the first slit section 11c and the second slit section 11d in the extension direction are the same as the lengths of the first slit section 11a and the second slit section 11b in the extension direction, a smaller junction angle reduces the amplitude of the column-side vibration. Furthermore, a smaller junction angle reduces the length of the peripheral-edge-side slit, thereby reducing the amplitude of the peripheral-edge-side vibration. Therefore, similar to the adjustment of the vibration characteristics of the first embodiment, it is preferable to achieve desired vibration characteristics by appropriately setting the lengths of the peripheral-edge-side slits 12B and / or the column-side slits 11B.

[0048] In this manner, also in this embodiment, the amplitude of the vibration membrane 3 can be made substantially uniform in the region between the pillar-side slits 11B and the corresponding periphery-side slits 12B. This is because the vibration membrane 3 including the movable electrode of the vibration portion 13B is displaced substantially parallel to the fixed electrode 5 facing it.

[0049] In this embodiment, as shown in Fig. 9, the signal output from each vibrating section is small because it is divided into six vibrating sections 13B. However, by providing multiple vibrating sections, the area of ​​the vibrating section that can be displaced in the radial direction of the vibrating membrane 3 and approximately parallel to the fixed electrode 5 increases, so that sufficiently high sensitivity can be obtained.

[0050] Furthermore, since the vibrating membrane 3 including the movable electrode is displaced substantially parallel to the fixed electrode 5, the AOP is improved. Furthermore, by using a vibrating membrane 3 with a small spring constant that is easy to vibrate, the force applied to each vibrating portion can be reduced when a bias voltage is applied between the fixed electrode 5 and the movable electrode of the vibrating portion, thereby reducing distortion of the detection signal and improving the AOP. In this embodiment, too, by providing the pillars 10, problems such as excessive vibration of the vibrating membrane 3 do not occur, even when a vibrating membrane 3 with a small spring constant is used. Furthermore, the lengths of the sub-slit portions that make up the peripheral edge side slits 12B are set to lengths that prevent the width of each sub-slit portion from expanding beyond the designed desired width, thereby suppressing a decrease in sensitivity, particularly in the low frequency range.

[0051] Furthermore, it is possible to have a configuration in which a plurality of vibrating parts with the same vibration characteristics are provided, and it is also possible to have a configuration in which vibrating parts with different vibration characteristics are combined to complement each other.

[0052] (Embodiment 3) Next, a third embodiment of the MEMS element of the present invention will be described. Fig. 10 corresponds to a plan view schematic diagram illustrating the vibration membrane portion of the MEMS element shown in Fig. 1, and is a diagram illustrating the arrangement of the pillars 10, pillar-side slits 11C, and peripheral edge-side slits 12C. In Fig. 1, the back chamber 9 formed in the substrate 1 is circular, and the outer periphery of Fig. 10 corresponds to the outer periphery of the back chamber 9 of the substrate 1. In the MEMS element of this embodiment shown in Fig. 10, the shape of the pillar-side slits 11C is different from that of the MEMS element described in the first embodiment shown in Fig. 2.

[0053] A detailed description will be given using one vibrating section as an example. A vibrating section 13C formed in the upper right region of the pillar 10 of the vibrating membrane 3 shown in FIG. 10 is provided with a first slit section 11e extending upward in the drawing from the pillar 10 side in parallel with the radial direction of the vibrating membrane 3, and a second slit section 11f extending rightward in the drawing from the pillar 10 side in parallel with the radial direction of the vibrating membrane 3 and joining to the first slit section 11e at a joining angle of 90 degrees. As shown in FIG. 10, the first slit section 11e and the second slit section 11f are each composed of a plurality of sub-slit sections extending in their extending directions. In this embodiment shown in FIG. 10, the first slit section 11e is composed of two sub-slit sections 11e1 and 11e2, and the second slit section 11f is also composed of two sub-slit sections 11f1 and 11f2. Sub-slit portion 11e1 constituting first slit portion 11e and sub-slit portion 11f1 constituting second slit portion 11f are joined so as to intersect at a joining angle of 90 degrees. The two or more sub-slit portions constituting first slit portion 11e are spaced apart and aligned in series in the extension direction of first slit portion 11e. The two or more sub-slit portions constituting second slit portion 11f are spaced apart and aligned in series in the extension direction of second slit portion 11f. The extension direction lengths of each sub-slit portion constituting first slit portion 11e and second slit portion 11f are set to lengths that do not warp vibrating membrane 3 and do not cause the width of each sub-slit portion to expand beyond the designed desired width.

[0054] Furthermore, the column-side slit 11C of the MEMS element of this embodiment is configured to include a fifth slit portion 11g and a sixth slit portion 11h. The fifth slit portion 11g is configured with one or more sub-slit portions and is arranged along the first slit portion 11e. The two or more sub-slit portions are arranged in series along the first slit portion 11e with a gap between them. The sixth slit portion 11f is configured with one or more sub-slit portions and is arranged along the second slit portion 11f. The two or more sub-slit portions are arranged in series along the second slit portion 11f with a gap between them. In the example shown in FIG. 10, the fifth slit portion 11g is configured with one sub-slit portion extending in the direction along the first slit portion 11e. The sixth slit portion 11h is configured with one sub-slit portion extending in the direction along the second slit portion 11f. The length in the extension direction of each sub-slit portion constituting the fifth slit portion 11g and the sixth slit portion 11h is set to a length that does not cause warping of the vibration membrane 3 and does not cause the width of each sub-slit portion to expand beyond the designed desired width.

[0055] As shown in FIG. 10, the multiple sub-slits constituting the first slit portion 11e and the multiple sub-slits constituting the fifth slit portion 11g are arranged alternately along the first slit portion 11e. The ends of the sub-slits constituting the first slit portion 11e and the ends of the sub-slits constituting the fifth slit portion 11g are arranged to overlap each other along the peripheral edge. The multiple sub-slits constituting the second slit portion 11f and the multiple sub-slits constituting the sixth slit portion 11h are arranged alternately along the second slit portion 11f. The ends of the sub-slits constituting the second slit portion 11f and the ends of the sub-slits constituting the sixth slit portion 11h are arranged to overlap each other along the peripheral edge. When the first slit portion 11e and the second slit portion 11f each have three or more sub-slits, the fifth slit portion 11g and the sixth slit portion 11h can each be composed of two or more sub-slits. With this configuration, the multiple sub-slits that make up the first slit portion 11e and the multiple sub-slits that make up the fifth slit portion 11g are arranged alternately in a direction along the first slit portion 11e. The ends of the sub-slits that make up the first slit portion 11e and the ends of the sub-slits that make up the fifth slit portion 11g are arranged so as to overlap with each other in a direction along the peripheral portion. The same applies to the sub-slits that make up the second slit portion 11f and the sub-slits that make up the sixth slit portion 11h. Furthermore, the fifth slit portion 11g and the sixth slit portion 11h can each be composed of multiple slits. With this configuration, the sub-slits that make up one of two adjacent slit portions (adjacent slit portions) among the first slit portion 11e and one or more fifth slit portions 11g and the sub-slits that make up the other adjacent slit portion are arranged alternately in a direction along the first slit portion 11e. The end of each sub-slit portion constituting one of the adjacent slit portions and the end of each sub-slit portion constituting the other of the adjacent slit portions are arranged so as to overlap each other in the direction along the peripheral edge portion.The same applies to the arrangement of two adjacent slit portions among the second slit portion 11f and one or more sixth slit portions 11h.

[0056] By forming the pillar-side slits 11C in this way, a portion of the diaphragm 3 on the pillar 10 side, whose vibration is restricted by the pillar 10, becomes more likely to vibrate. Note that, because the pillar-side slits 11C are configured as sub-slits, the length of the pillar-side slits 11C in the extension direction, indicated by the two-dot chain line in Fig. 10, can be set appropriately. Therefore, a configuration may be adopted in which the pillar-side slits 11C are arranged up to the vicinity of the periphery-side slits 12C, and part of the sub-slits configuring the pillar-side slits 11C adjusts the vibration characteristics of the diaphragm 3 on the periphery side.

[0057] The peripheral edge slits 12C are formed so as to open to the position where they intersect with the extension lines of the first slits 11e and the second slits 11f, or to the vicinity thereof, in order to form a single vibration section in the region sandwiched between the extension lines of the first slits 11e and the extension lines of the second slits 11f, both of which are shown by two-dot chain lines in Fig. 10. The peripheral edge slits 12C of this embodiment correspond to the peripheral edge slits 12A described in the first embodiment above, and are composed of the third slits 12e and the fourth slits 12f.

[0058] In this way, the area surrounded by the pillar-side slit 11C and the peripheral-side slit 12C becomes one vibrating part 13C. The multiple vibrating parts 13C are evenly arranged around the center of the pillar 10 (the center of the vibrating membrane 3), resulting in four vibrating parts with uniform characteristics.

[0059] The vibration characteristics of the vibrating part 13C of the MEMS element of this embodiment show similar trends to those of the vibrating part 13A of the above-described embodiment 1. Specifically, the vibration characteristics of the vibrating part 13C vary depending on the material, thickness, and size of the vibrating membrane 3. Furthermore, the vibration characteristics vary depending on the shapes and arrangements of the pillar-side slits 11C and the periphery-side slits 12C.

[0060] Therefore, like the vibrating part 13A of the first embodiment, the vibrating part 13C of the MEMS element of this embodiment also exhibits vibration characteristics similar to those shown in Figures 3 to 8. When the length of the pillar-side slit is increased to adjust the vibration characteristics of the vibrating membrane, by configuring the pillar-side slit as in 11C of the MEMS element of this embodiment, the width of the pillar-side slit will not increase beyond the designed desired width, and a decrease in sensitivity, particularly in the low-frequency range, is suppressed.

[0061] Although the present embodiment has been described taking as an example a MEMS element having four vibrating parts 13C, it is also possible to apply the present embodiment to a MEMS element having six vibrating parts as in the second embodiment above.

[0062] In this embodiment as well, the amplitude of the vibrating membrane 3 can be made substantially uniform in the region between the pillar-side slits 11C and the corresponding periphery-side slits 12C. This is because the vibrating membrane 3 including the movable electrode of the vibrating portion 13C is displaced substantially parallel to the fixed electrode 5 facing it.

[0063] In this embodiment, as shown in Fig. 10, the signal output from each vibrating section is small because it is divided into four vibrating sections 13C. However, since multiple vibrating sections are provided and the area of ​​the vibrating section that can be displaced in the radial direction of the vibrating membrane 3 substantially parallel to the fixed electrode 5 increases, it is possible to obtain sufficiently high sensitivity.

[0064] Furthermore, the vibrating membrane 3, including the movable electrode, is displaced substantially parallel to the fixed electrode 5, improving the AOP. Furthermore, by using a vibrating membrane 3 with a small spring constant that is easy to vibrate, the force applied to each vibrating unit can be reduced when a bias voltage is applied between the fixed electrode 5 and the movable electrode of the vibrating unit, thereby reducing distortion of the detection signal and improving the AOP. In this embodiment, too, by providing the pillar 10, problems such as excessive vibration of the vibrating membrane 3 do not occur, even when the vibrating membrane 3 has a small spring constant. Furthermore, the lengths of the sub-slit portions that constitute the pillar-side slit 11C and the periphery-side slit 12C are set to lengths that prevent the width of each sub-slit portion from expanding beyond the designed desired width, thereby suppressing a decrease in sensitivity, particularly in the low-frequency range.

[0065] Furthermore, it is possible to have a configuration in which a plurality of vibrating parts with the same vibration characteristics are provided, and it is also possible to have a configuration in which vibrating parts with different vibration characteristics are combined to complement each other.

[0066] (Embodiment 4) Next, a fourth embodiment of the MEMS element of the present invention will be described. Fig. 11 corresponds to a plan view schematic diagram illustrating the vibration membrane portion of the MEMS element shown in Fig. 1, and is a diagram illustrating the arrangement of pillars 10, pillar-side slits 11D, and peripheral edge-side slits 12D. In Fig. 1, the back chamber 9 formed in the substrate 1 is circular, and the outer periphery of Fig. 11 corresponds to the outer periphery of the back chamber 9 of the substrate 1. In the MEMS element of this embodiment shown in Fig. 11, the shape of the peripheral edge-side slits 12D is different from that of the MEMS element described in the first embodiment shown in Fig. 2.

[0067] A detailed description will be given taking one vibrating section as an example. In vibrating section 13D formed in the upper right region of pillar 10 of vibrating membrane 3 shown in Fig. 11, a first slit section 11i extending upward in the drawing from the pillar 10 side parallel to the radial direction of vibrating membrane 3, and a second slit section 11j extending rightward in the drawing from the pillar 10 side parallel to the radial direction of vibrating membrane 3 and joining to first slit section 11i at a joining angle of 90 degrees are formed. Pillar-side slit 11D of the MEMS element of this embodiment corresponds to pillar-side slit 11A described in the first embodiment above.

[0068] By forming the pillar-side slit 11D, a part of the diaphragm 3 on the pillar 10 side, whose vibration is restricted by the pillar 10, becomes more likely to vibrate.

[0069] The peripheral edge slits 12D are formed so as to open to the position where they intersect with or near the intersection of the extension lines, which are the extension lines of the first slits 11i and the second slits 11j, respectively, shown by the two-dot chain lines in Fig. 11, in order to form a single vibration section in the region sandwiched between these extension lines. The peripheral edge slits 12D of the MEMS element of this embodiment include a third slit 12g and a fourth slit 12h, and further include one or more seventh slits. In the example shown in Fig. 11, two seventh slits 12i and 12j are provided.

[0070] The third slit portion 12g and the fourth slit portion 12h constituting the peripheral edge slit 12D of this embodiment correspond to the third slit portion 12a and the fourth slit portion 12b constituting the peripheral edge slit 12A described in the first embodiment. As shown in FIG. 11, the seventh slit portion 12i is disposed on the column 10 side of the fourth slit portion 12h. The seventh slit portion 12i is composed of a plurality of sub-slit portions extending in a direction along the fourth slit portion 12h. In this embodiment shown in FIG. 11, the seventh slit portion 12i is composed of two sub-slit portions 12i1 and 12i2. The seventh slit portion 12j is disposed on the column 10 side of the seventh slit portion 12i. The seventh slit portion 12j is composed of a plurality of sub-slit portions extending in a direction along the seventh slit portion 12i. In this embodiment shown in FIG. 11, the seventh slit portion 12j is composed of three sub-slit portions 12j1, 12j2, and 12j3. The length in the extension direction of each sub-slit portion constituting the third slit portion 12g, the fourth slit portion 12h, the seventh slit portion 12i, and 12j is set to a length that does not cause warping of the vibration membrane 3 and does not cause the width of each sub-slit portion to expand beyond the designed desired width.

[0071] 11, the sub-slits constituting one of two adjacent slits (adjacent slits) among the third slit 12g, the fourth slit 12h, and the seventh slits 12i and 12j, and the sub-slits constituting the other of these adjacent slits, are arranged alternately in a direction along the periphery. The ends of the sub-slits constituting the slits of the adjacent slits arranged closer to the periphery and the ends of the sub-slits constituting the slits of the adjacent slits arranged closer to the pillar 10 are arranged to overlap each other in a direction from the center of the diaphragm 3 toward the periphery.

[0072] In this way, the area surrounded by the pillar-side slit 11D and the peripheral-side slit 12D becomes one vibrating section 13D. The multiple vibrating sections 13D are evenly arranged around the center of the pillar 10 (the center of the vibrating membrane 3), resulting in four vibrating sections with uniform characteristics.

[0073] The vibration characteristics of the vibrating section 13D of this embodiment show similar trends to those of the vibrating section 13A of the above-described embodiment 1. Specifically, the vibration characteristics of the vibrating section 13D vary depending on the material, thickness, and size of the vibrating membrane 3. Furthermore, the vibration characteristics vary depending on the shapes and arrangements of the pillar-side slits 11D and the periphery-side slits 12D.

[0074] Therefore, like the vibrating section 13A of the first embodiment, the vibrating section 13D of the MEMS element of this embodiment also exhibits vibration characteristics similar to those shown in FIGS. 3 to 8. In particular, the MEMS element of this embodiment can increase the amplitude of vibration on the peripheral side without increasing the length of the sub-slits that form the peripheral-side slits 12D. FIG. 12 is a diagram illustrating the vibration characteristics of the vibrating section 13D of the MEMS element of this embodiment. The vertical axis of FIG. 12 represents the amplitude of vibration. The horizontal axis of FIG. 12 represents the distance from the center of the vibrating membrane 3, which is the radial direction of the vibrating membrane 3 that passes through the junction between the first slit portion 11i and the second slit portion 11j of the pillar-side slit 11D from the center of the pillar 10. The horizontal axis represents the relative distance, with the center of the pillar 10 being 0.00 and the outer periphery shown in FIG. 11 being 1.00. FIG. 12 compares the vibration characteristics of the vibrating membrane G of the MEMS element of this embodiment with those of the vibrating membrane A described in the first embodiment. Here, the configurations of the first slit portion and the second slit portion of the pillar-side slit and the configurations of the third slit portion and the fourth slit portion of the peripheral edge-side slit are the same.

[0075] 12, it can be seen that both the diaphragm A and the diaphragm G vibrate at the pillar-side slit 11D and the periphery-side slit 12D. It can also be seen that in the MEMS element having the diaphragm G of this embodiment, the amplitude on the periphery side is larger.

[0076] In this embodiment, the signal output from each vibrating section is small because the vibrating membrane 3 is divided into four vibrating sections 13D as shown in Fig. 11. However, by providing multiple vibrating sections, the area of ​​the vibrating sections that displace in the radial direction of the vibrating membrane 3 almost parallel to the fixed electrode 5 as shown in Fig. 11 is further increased, so that sufficiently high sensitivity can be obtained.

[0077] Furthermore, since the vibrating membrane 3 including the movable electrode is displaced substantially parallel to the fixed electrode 5, the AOP is improved. Furthermore, by using a vibrating membrane 3 with a small spring constant that is easy to vibrate, the force applied to each vibrating portion can be reduced when a bias voltage is applied between the fixed electrode 5 and the movable electrode of the vibrating portion, thereby reducing distortion of the detection signal and improving the AOP. In this embodiment, too, by providing the pillars 10, problems such as excessive vibration of the vibrating membrane 3 do not occur even when a vibrating membrane 3 with a small spring constant is used. Furthermore, the lengths of the sub-slit portions that make up the peripheral edge side slits 12D are set to lengths that prevent the width of each sub-slit portion from expanding beyond the desired designed width, thereby suppressing a decrease in sensitivity, particularly in the low frequency range.

[0078] Furthermore, it is possible to have a configuration in which a plurality of vibrating parts with the same vibration characteristics are provided, and it is also possible to have a configuration in which vibrating parts with different vibration characteristics are combined to complement each other.

[0079] Although this embodiment has been described taking as an example a MEMS element having four vibrating parts 13D, it is also possible to apply this to a MEMS element having six vibrating parts as shown in the above-mentioned embodiment 2. Furthermore, like the pillar-side slit 11C described in the above-mentioned embodiment 3, the pillar-side slit 11D can be configured with two or more slit parts to achieve desired vibration characteristics.

[0080] (Embodiment 5) Next, a fifth embodiment of the MEMS element of the present invention will be described. In the first to fourth embodiments, the peripheral edge slits 12 were through-holes in the diaphragm 3. In contrast, this embodiment differs in that, as shown in FIG. 13, a portion of the peripheral edge slits of the MEMS element is an opening formed between the open end of the diaphragm 3 and the surface facing this open end. FIG. 13 is a schematic cross-sectional view illustrating the fifth embodiment of the MEMS element of the present invention. FIG. 14 is a schematic plan view illustrating the diaphragm portion of the MEMS element shown in FIG. 13, viewed from the backplate 7 side, excluding the backplate 7. The MEMS element 200 according to this embodiment differs from the MEMS element 100 shown in FIG. 1 described in the first embodiment in that the support structure of the diaphragm 3, including the movable electrode, is different, and a portion of the end of the diaphragm 3 is an open end. In FIG. 13, the surface facing the open end of the diaphragm 3 is the inner wall surface of the spacer 4 that faces the open end of the diaphragm 3. However, the surface facing the open end of the diaphragm 3 is not limited to the inner wall surface of the spacer 4. The surface facing the open end of the vibrating membrane 3 may be, for example, the inner side surface of the insulating film 2 or the inner wall surface of the substrate 1 facing the back chamber 9.

[0081] In the MEMS element of this embodiment, a portion of the periphery of the vibrating membrane 3 forms an open end facing the substrate 1, the insulating film 2, or the spacer 4, and the portion of the periphery of the vibrating membrane 3 other than the open end forms the support portion 14. The cross-sectional schematic diagram shown in Fig. 13 shows a cross-section passing through the center of the pillar 10 in Fig. 14, two pillar-side slits 11E that face each other with the pillar 10 as the center, and third slit portion 12k of the peripheral-side slit 12E that is configured by the end of the vibrating membrane 3 that forms an open end. Therefore, the support portion 14 of the vibrating membrane 3 is not shown in Fig. 13, and the structure is such that the support portion 14 of the vibrating membrane 3 is layered on the insulating film 2 in an area not shown, and the spacer 4 is layered on this support portion 14.

[0082] This peripheral edge side slit 12E corresponds to the peripheral edge side slits 12A to 12C described in the first to third embodiments. Therefore, as shown in FIG. 14, when the portion of the vibrating membrane 3 corresponding to the back chamber 9 is circular, the pillar 10 is arranged on the vibrating membrane 3 so that the center of the vibrating membrane 3 and the center of the circular pillar 10 coincide with each other. A plurality of vibrating portions 13E are formed in the region between the joint between the vibrating membrane 3 and the pillar 10 and the peripheral edge of the vibrating membrane 3. For this purpose, the pillar side slit 11E and the peripheral edge side slit 12E are arranged around the pillar 10. In the present embodiment shown in FIG. 14, an example in which four vibrating portions 13E are formed is shown.

[0083] A detailed description will be given taking one vibrating section as an example. In vibrating section 13E formed in the upper right region of pillar 10 of vibrating membrane 3 shown in Fig. 14, pillar-side slits 11E are formed by first slits 11k extending upward in the drawing from the pillar 10 side parallel to the radial direction of vibrating membrane 3, and second slits 11l extending rightward in the drawing from the pillar 10 side parallel to the radial direction of vibrating membrane 3 and joining to first slits 11k at a joining angle of 90 degrees. Pillar-side slits 11E of the MEMS element of this embodiment correspond to pillar-side slits 11A described in the first embodiment above.

[0084] By forming the pillar-side slit 11E, the part of the diaphragm 3 on the pillar 10 side, whose vibration is restricted by the pillar 10, becomes more likely to vibrate.

[0085] The peripheral edge slits 12E are formed so as to open to the position where they intersect with the extension lines of the first slits 11k and the second slits 11l, respectively, shown by the two-dot chain lines in Fig. 14, or to the vicinity thereof, in order to form a single vibrating section in the region sandwiched between these extension lines. The peripheral edge slits 12E of the MEMS element of this embodiment are composed of a third slit 12k and a fourth slit 12l. The third slit 12k is formed by the open end of the vibrating membrane 3.

[0086] As shown in FIG. 14, the third slit portion 12k is composed of a plurality of sub-slit portions extending in a direction along the peripheral edge of the diaphragm 3. In the present embodiment shown in FIG. 14, the third slit portion 12k is composed of two sub-slit portions 12k1 and 12k2. The two or more sub-slit portions constituting the third slit portion 12k are arranged in series along the peripheral edge of the diaphragm 3 with a gap between them. The fourth slit portion 12l is disposed on the pillar 10 side of the third slit portion 12k. The fourth slit portion 12l is composed of a plurality of sub-slit portions extending in a direction along the third slit portion 12k. In the present embodiment shown in FIG. 14, the fourth slit portion 12l is composed of three sub-slit portions 12l1, 12l2, and 12l3. The two or more sub-slit portions constituting the fourth slit portion 12l are arranged in series along the third slit portion 12k with a gap between them. The length in the extension direction of each sub-slit portion constituting the third slit portion 12k and the fourth slit portion 12l is set to a length that does not cause warping of the vibration membrane 3 and does not cause the width of each sub-slit portion to expand beyond the designed desired width.

[0087] 14, the plurality of sub-slit portions constituting third slit portion 12k and the plurality of sub-slit portions constituting fourth slit portion 12l are arranged alternately in a direction along the peripheral edge of vibrating membrane 3. The ends of the sub-slit portions constituting third slit portion 12k and the ends of the sub-slit portions constituting fourth slit portion 12l are arranged so as to overlap with each other in a direction from the center of vibrating membrane 3 to the peripheral edge. By arranging third slit portion 12k and fourth slit portion 12l in this manner, the peripheral edge of the region sandwiched between the extension lines of column-side slit 11E, each indicated by a two-dot chain line in FIG. 14, alternates between portions where either third slit portion 12k or fourth slit portion 12l is arranged and portions where both third slit portion 12k and fourth slit portion 12l are arranged.

[0088] In this way, the area surrounded by the pillar-side slit 11E and the peripheral-side slit 12E becomes one vibrating part 13E. The multiple vibrating parts 13E are evenly arranged around the center of the pillar 10 (the center of the vibrating membrane 3), resulting in four vibrating parts with uniform characteristics.

[0089] The vibration characteristics of the vibrating section 13E of this embodiment show the same tendency as those of the vibrating section 13A of the above-described embodiment 1. Specifically, the vibration characteristics of the vibrating section 13E vary depending on the material, thickness, and size of the vibrating membrane 3. Furthermore, the vibration characteristics vary depending on the shapes and arrangements of the pillar-side slits 11E and the periphery-side slits 12E.

[0090] Therefore, like the vibrating part 13A of the first embodiment, the vibrating part 13E of the MEMS element of this embodiment also exhibits vibration characteristics similar to those shown in Figures 3 to 8. When comparing the vibrating part of this embodiment with the vibrating part of the first embodiment, the vibrating membrane 3 of this embodiment has a smaller area that is bonded to the substrate 1, etc., and is therefore less susceptible to the effects of deformation of the substrate 1, etc.

[0091] In this manner, also in this embodiment, the amplitude of the vibration membrane 3 can be made substantially uniform in the region between the pillar-side slits 11E and the corresponding periphery-side slits 12E. This is because the vibration membrane 3 including the movable electrode of the vibration portion 13E is displaced substantially parallel to the fixed electrode 5 facing it.

[0092] In this embodiment, as shown in Fig. 14, the signal output from each vibrating section is small because it is divided into four vibrating sections 13E. However, by providing multiple vibrating sections, the area of ​​the vibrating section that can be displaced in the radial direction of the vibrating membrane 3 and approximately parallel to the fixed electrode 5 increases, making it possible to obtain sufficiently high sensitivity.

[0093] Furthermore, since the vibrating membrane 3 including the movable electrode is displaced substantially parallel to the fixed electrode 5, the AOP is improved. Furthermore, by using a vibrating membrane 3 with a small spring constant that is easy to vibrate, the force applied to each vibrating portion can be reduced when a bias voltage is applied between the fixed electrode 5 and the movable electrode of the vibrating portion, thereby reducing distortion of the detection signal and improving the AOP. In this embodiment, too, by providing the pillars 10, problems such as excessive vibration of the vibrating membrane 3 do not occur, even when a vibrating membrane 3 with a small spring constant is used. Furthermore, the lengths of the sub-slit portions that make up the peripheral edge side slits 12E are set to lengths that prevent the width of each sub-slit portion from expanding beyond the designed desired width, thereby suppressing a decrease in sensitivity, particularly in the low frequency range.

[0094] Furthermore, it is possible to have a configuration in which a plurality of vibrating parts with the same vibration characteristics are provided, and it is also possible to have a configuration in which vibrating parts with different vibration characteristics are combined to complement each other.

[0095] Although this embodiment has been described taking as an example a MEMS element having four vibrating portions 13E, it is also possible to apply this to a MEMS element having six vibrating portions as in the above-described embodiment 2. Furthermore, in order to increase the amplitude in the vicinity of the support portion 14, the peripheral portion-side slit 12E can be configured with three or more slit portions as described in the above-described embodiment 4, and the amplitude in the vicinity of the peripheral portion of the vibrating membrane 3 can be changed to achieve desired vibration characteristics. Furthermore, like the pillar-side slit 11C described in the above-described embodiment 3, the pillar-side slit 11E can be configured with two or more slit portions to achieve desired vibration characteristics.

[0096] (summary) (1) One embodiment of a MEMS element of the present invention is a MEMS element including a substrate with a back chamber, a vibration membrane including a movable electrode bonded onto the substrate, and a back plate including a fixed electrode arranged opposite the movable electrode, wherein the vibration membrane has a pillar in its center that connects the back plate and the vibration membrane, and has a plurality of vibration parts in an area between a joint between the pillar and the vibration membrane and a peripheral edge of the vibration membrane, each of the plurality of vibration parts being formed by an area surrounded by a pillar-side slit including a first slit part and a second slit part that are bonded to each other, and a peripheral edge-side slit, the first slit part and the second slit part extending in mutually different directions from the joint side between the pillar and the vibration membrane toward the peripheral edge, and the peripheral edge-side slit extends from the first slit part to the peripheral edge. and an extension line from the second slit portion toward the peripheral portion, the peripheral portion-side slit includes a third slit portion that is located inside the peripheral portion of the vibrating membrane and extends in a direction along the peripheral portion, and a fourth slit portion that is located on the pillar side of the third slit portion and extends in a direction along the third slit portion, the third slit portion and the fourth slit portion each being composed of a plurality of sub-slit portions, the sub-slit portions that constitute the third slit portion and the sub-slit portions that constitute the fourth slit portion are arranged alternately in the direction along the peripheral portion, and the ends of the sub-slit portions that constitute the third slit portion and the sub-slit portions that constitute the fourth slit portion are arranged so as to overlap each other in the direction from the central portion toward the peripheral portion.

[0097] According to the MEMS element of the embodiment (1) above, by arranging a pillar that connects to the backplate in the center of the diaphragm, the amplitude of the diaphragm at the center is suppressed. Furthermore, by providing a pillar-side slit and a peripheral-side slit in the diaphragm, a vibrating section with a small difference in amplitude between the center and peripheral portions of the diaphragm can be formed. Multiple such vibrating sections are formed, allowing a large overall detection signal to be obtained. The peripheral-side slit does not expand beyond the designed desired width, and sensitivity, particularly in the low-frequency range, is not reduced. Furthermore, by increasing the amplitude of the vibrating section and dividing it into multiple vibrating sections, the force applied to each vibrating section can be reduced when a bias voltage is applied between the fixed electrode and movable electrode of the vibrating section, thereby reducing distortion of the detection signal.

[0098] (2) According to another embodiment, in the MEMS element of (1) above, the third slit portion is an opening between the open end of the vibration membrane and the surface opposite to the open end, thereby easily changing the vibration characteristics of the vibration membrane.

[0099] (3) According to yet another embodiment, in the MEMS element of (1) or (2) above, the pillar-side slit further includes one or more fifth slit portions extending in a direction along the first slit portion and one or more sixth slit portions extending in a direction along the second slit portion, the first slit portion and the second slit portion each being composed of a plurality of sub-slit portions, the one or more fifth slit portions and the one or more sixth slit portions each being composed of one or more sub-slit portions, and each sub-slit portion constituting one of two adjacent slit portions among the first slit portion and the one or more fifth slit portions and each sub-slit portion constituting the other of the two adjacent slit portions is arranged along the first slit portion. The second slit section and the one or more sixth slit sections are arranged alternately in the direction along the second slit section, and the ends of each sub-slit section constituting one of the two adjacent slit sections and the ends of each sub-slit section constituting the other of the two adjacent slit sections are arranged so as to overlap each other in the direction along the peripheral edge, and the second slit section and the one or more sixth slit sections are arranged alternately in the direction along the second slit section, and the ends of each sub-slit section constituting one of the two adjacent slit sections and the ends of each sub-slit section constituting the other of the two adjacent slit sections are arranged so as to overlap each other in the direction along the peripheral edge.

[0100] According to the MEMS element of the embodiment (3) above, the pillar-side slits do not widen beyond the designed desired width, and the sensitivity, particularly in the low frequency range, does not decrease.

[0101] (4) According to yet another embodiment, in the MEMS element of (1) or (2) above, the peripheral side slit is arranged on the pillar side of the fourth slit portion and further includes one or more seventh slit portions extending in a direction along the fourth slit portion, and the one or more seventh slit portions are each composed of a plurality of sub-slit portions, and the sub-slit portions constituting one of two adjacent slit portions among the fourth slit portion and the one or more seventh slit portions and the sub-slit portions constituting the other of the two adjacent slit portions are arranged alternately in a direction along the fourth slit portion, and the ends of the sub-slit portions constituting one of the two adjacent slit portions and the ends of the sub-slit portions constituting the other of the two adjacent slit portions are arranged so as to overlap each other in a direction from the central portion toward the peripheral portion.

[0102] According to the MEMS element of the embodiment (4) above, it is possible to change the vibration characteristics of the peripheral portion to form a vibrating portion with a small difference in amplitude between the central portion and the peripheral portion of the vibrating membrane, thereby obtaining a large detection signal.

[0103] (5) According to yet another embodiment, in the MEMS element of (1) or (2) above, the plurality of vibration parts can be vibration parts each having the same vibration characteristics, thereby making it possible to obtain a large detection signal.

[0104] (6) According to yet another embodiment, in the MEMS element of (1) or (2) above, the plurality of vibration parts are configured to include at least two vibration parts having different vibration characteristics. This makes it possible to change the vibration characteristics of the central part or the peripheral part of the vibration membrane, respectively, to form vibration parts with a small difference in amplitude between the central part and the peripheral part of the vibration membrane, and to obtain a large detection signal.

[0105] (7) According to yet another embodiment, in the MEMS element of (1) or (2) above, all of the plurality of vibrating parts are configured to have the column-side slits and the peripheral-side slits of the same shape, thereby making it possible to obtain a large detection signal.

[0106] (8) According to yet another embodiment, in the MEMS element of (1) or (2) above, the plurality of vibration parts are configured to include at least two vibration parts having at least one of the pillar-side slits and the peripheral-side slits having different shapes from each other. This makes it possible to change the vibration characteristics of the central part or the peripheral part of the vibration membrane, respectively, to form vibration parts with a small difference in amplitude between the central part and the peripheral part of the vibration membrane, and to obtain a large detection signal.

[0107] (9) According to yet another embodiment, in the MEMS element of (1) or (2) above, the first slit portion and the second slit portion constituting the pillar-side slit are configured to have a length and / or a bond angle that allows predetermined vibration characteristics to be obtained. This changes the vibration characteristics of the central portion of the vibrating membrane, thereby forming a vibrating portion with a small difference in amplitude between the central portion and the peripheral portion of the vibrating membrane, and thereby allows a large detection signal to be obtained.

[0108] (10) According to yet another embodiment, in the MEMS element of (1) or (2) above, the sub-slit portion constituting the peripheral side slit and / or the sub-slit portion constituting the pillar side slit are each configured to be formed at a length and / or interval that will provide predetermined vibration characteristics. This allows the vibration characteristics of the peripheral and / or central portions of the vibrating membrane to be changed, forming a vibrating portion with a small difference in amplitude between the central and peripheral portions of the vibrating membrane, and thereby obtaining a large detection signal. [Explanation of symbols]

[0109] 1 board 2. Insulating film 3. Diaphragm 4 spacers 5 Fixed electrode 6. Insulating film 7 Backplate 8 Acoustic Hall 9 Back Chamber 10 pillars 11, 11A~11E Pillar side slit 11a, 11c, 11e, 11i, 11k First slit section 11b, 11d, 11f, 11j, 11l Second slit section 11g 5th slit 11h 6th slit 12, 12A~12E Peripheral slits 12a, 12c, 12e, 12g, 12k Third slit section 12b, 12d, 12f, 12h, 12l 4th slit section 12i, 12j 7th slit 13, 13A~13E Vibration part 14 Support part

Claims

1. a substrate having a back chamber; a vibrating membrane including a movable electrode bonded onto the substrate; a back plate including a fixed electrode arranged opposite to the movable electrode; A MEMS element comprising: The vibrating membrane is a pillar at the center thereof that connects the back plate and the diaphragm; a plurality of vibration parts in a region between a joint between the pillar and the vibration membrane and a peripheral edge of the vibration membrane; each of the plurality of vibration sections is formed from an area surrounded by a column-side slit including a first slit section and a second slit section joined to each other, and a peripheral-edge-side slit; the first slit portion and the second slit portion extend in different directions from each other from a joint between the pillar and the vibration membrane toward the peripheral edge portion, the peripheral edge portion-side slit is disposed in the peripheral edge portion between an extension line from the first slit portion toward the peripheral edge portion and an extension line from the second slit portion toward the peripheral edge portion, the peripheral portion-side slit includes a third slit portion that is disposed inside the peripheral portion of the vibration membrane and extends in a direction along the peripheral portion, and a fourth slit portion that is disposed on the pillar side of the third slit portion and extends in a direction along the third slit portion, the third slit portion and the fourth slit portion each include a plurality of sub-slit portions, Each sub-slit portion constituting the third slit portion and each sub-slit portion constituting the fourth slit portion are are staggered in a direction along the periphery; and an end portion of each sub-slit portion constituting the third slit portion and an end portion of each sub-slit portion constituting the fourth slit portion are arranged so as to overlap with each other in a direction from the central portion toward the peripheral edge portion; MEMS element.

2. the third slit portion is an opening between an open end of the vibration membrane and a surface facing the open end, The MEMS element according to claim 1 .

3. the column-side slit further includes one or more fifth slit portions extending in a direction along the first slit portion and one or more sixth slit portions extending in a direction along the second slit portion, the first slit portion and the second slit portion each include a plurality of sub-slit portions, the one or more fifth slit portions and the one or more sixth slit portions are each composed of one or more sub-slit portions, the first slit portion and each sub-slit portion constituting one of two adjacent slit portions among the one or more fifth slit portions and each sub-slit portion constituting the other of the two adjacent slit portions are arranged alternately in a direction along the first slit portion, and an end of each sub-slit portion constituting one of the two adjacent slit portions and an end of each sub-slit portion constituting the other of the two adjacent slit portions are arranged so as to overlap each other in a direction along the peripheral edge portion; The second slit portion and each sub-slit portion constituting one of two adjacent slit portions among the one or more sixth slit portions and each sub-slit portion constituting the other of the two adjacent slit portions are arranged alternately in a direction along the second slit portion, and an end portion of each sub-slit portion constituting one of the two adjacent slit portions and an end portion of each sub-slit portion constituting the other of the two adjacent slit portions are arranged so as to overlap each other in a direction along the peripheral portion. The MEMS element according to claim 1 or 2.

4. the peripheral edge portion-side slit further includes one or more seventh slit portions that are arranged on the pillar side of the fourth slit portion and extend in a direction along the fourth slit portion, each of the one or more seventh slit portions is composed of a plurality of sub-slit portions; The sub-slit portions constituting one of two adjacent slit portions among the fourth slit portion and the one or more seventh slit portions and the sub-slit portions constituting the other of the two adjacent slit portions are arranged alternately in a direction along the fourth slit portion, and an end portion of each sub-slit portion constituting one of the two adjacent slit portions and an end portion of each sub-slit portion constituting the other of the two adjacent slit portions are arranged so as to overlap each other in a direction from the central portion toward the peripheral portion. The MEMS element according to claim 1 or 2.

5. The plurality of vibration units are vibration units having the same vibration characteristics. The MEMS element according to claim 1 or 2.

6. The plurality of vibration units include at least two vibration units having vibration characteristics different from each other. The MEMS element according to claim 1 or 2.

7. All of the plurality of vibration parts have the pillar-side slits of the same shape and the peripheral-edge-side slits of the same shape. The MEMS element according to claim 1 or 2.

8. the plurality of vibration units include at least two vibration units having at least one of the pillar-side slits having mutually different shapes and the peripheral-edge-side slits having mutually different shapes, The MEMS element according to claim 1 or 2.

9. The first slit portion and the second slit portion constituting the column-side slit are formed with a length and / or a coupling angle that allows predetermined vibration characteristics to be obtained. The MEMS element according to claim 1 or 2.

10. The sub-slit portion constituting the peripheral edge portion-side slit and / or the sub-slit portion constituting the column-side slit are each formed with a length and / or interval that allows predetermined vibration characteristics to be obtained. The MEMS element according to claim 1 or 2.

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