Micromechanical thin film structures of MEMS devices

Abstract

The present invention discloses a micromechanical film structure of a MEMS device, the micromechanical film structure comprising: a substrate; an anchor seat, the anchor seat is arranged on the substrate; a film member, the film member is connected to the anchor seat, the film member has a set direction away from the anchor seat and multiple effective widths arranged in sequence along the set direction, the effective width is the cross-sectional width of the film member on a cross-sectional plane perpendicular to the set direction or the sum of the cross-sectional widths, and the multiple effective widths gradually decrease along the set direction. The present invention makes the effective width of the film member gradually decrease along the set direction, so that the stress on the film member is evenly distributed, the stress concentration point is eliminated, and thus fatigue, creep, plastic deformation and other phenomena are weakened, and reliability is improved.

Description

Technical Field

[0001] The invention relates to the technical field of parts of MEMS devices, and in particular to a micromechanical film structure of a MEMS device. Background Art

[0002] Micromechanical film structures are typical components in MEMS (micro-electromechanical systems) devices. Micromechanical film structures are usually suspended structures, equipped with drive electrodes, which can realize the movement and deformation of micromechanical film structures. The materials of micromechanical film structures are generally divided into metals, non-metals, mixed film layers, etc. For these materials, when they are subjected to mechanical stress during operation, there are basically stress concentration points. For example, a single-ended clamped beam of metal material will bend and deform under the static force of the drive electrode. Its stress concentration point is at the root of the single-ended clamped beam. Irreversible damage such as fatigue, creep, and plastic deformation will easily occur at the stress concentration point, which will bring hidden dangers to the reliability and life of MEMS devices. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a micro-mechanical film structure of a MEMS device, which eliminates stress concentration points and improves reliability and service life.

[0004] According to an embodiment of the present invention, a micromechanical film structure of a MEMS device includes: a substrate; an anchor seat, which is arranged on the substrate; a film member, which is connected to the anchor seat, and the film member has a set direction away from the anchor seat and multiple effective widths arranged in sequence along the set direction, the effective width is the cross-sectional width of the film member on a cross-sectional plane perpendicular to the set direction or the sum of the cross-sectional widths, and the multiple effective widths gradually decrease along the set direction.

[0005] According to the micromechanical film structure of the embodiment of the present invention, the effective width of the film part is gradually reduced along a set direction, so that the stress on the film part is evenly distributed, and stress concentration points are eliminated, thereby reducing fatigue, creep, plastic deformation and other phenomena and improving reliability.

[0006] In some embodiments, the film member is provided with a hole, the section plane passes through the hole so that at least two cross sections are formed on the film member, and the effective width is the sum of the widths of the at least two cross sections.

[0007] Further, the hole portion includes a plurality of hole units, and the plurality of hole units are arranged at intervals along the set direction.

[0008] Furthermore, each of the hole units includes at least one through hole, and the distribution of the through holes of the plurality of hole units obeys the Cantor set.

[0009] In some specific embodiments, the widths of the plurality of hole units arranged along the set direction gradually increase.

[0010] Specifically, the widths of the plurality of hole units obey a number sequence, and the number sequence of the number sequence is any one of a geometric sequence, an arithmetic sequence, a difference ratio sequence, and a power sequence.

[0011] In some embodiments, the hole portion extends along the set direction, and the width of the hole portion gradually increases along the set direction.

[0012] Specifically, the hole walls of the hole portion located on both sides of the set direction are arc-shaped transitions or step-shaped transitions.

[0013] In some embodiments, the film member is configured such that a width of the film member gradually decreases along the set direction.

[0014] Specifically, the ends of the film member located on both sides of the setting direction are arc-shaped transitions or step-shaped transitions.

[0015] In some embodiments, the film member includes a mass member and at least two beam members, one end of each of the beam members is connected to the anchor seat and the other end is connected to the mass member, and the width of each of the beam members gradually decreases along the set direction.

[0016] In some embodiments, the film member is constructed as a beam or a film.

[0017] Specifically, the beam body is a single-end clamped beam or a double-end clamped beam, wherein when the beam body is a double-end clamped beam, the set direction includes a first direction and a second direction in opposite directions, and the multiple effective widths include two groups, one of the two groups of effective widths is set along the first direction, and the other group is set along the second direction.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0020] Figure 1 A schematic diagram of a micromechanical film structure in a first embodiment of the present invention;

[0021] Figure 2 A schematic diagram of a micromechanical film structure in a second embodiment of the present invention;

[0022] Figure 3A schematic diagram of a micromechanical film structure in a third embodiment of the present invention;

[0023] Figure 4 is a schematic diagram of a micromechanical film structure in a fourth embodiment of the present invention;

[0024] Figure 5 is a schematic diagram of a micromechanical film structure in a fifth embodiment of the present invention;

[0025] Figure 6 is a schematic diagram of a micromechanical film structure in a sixth embodiment of the present invention;

[0026] Figure 7 is a schematic diagram of a micromechanical film structure in a seventh embodiment of the present invention;

[0027] Figure 8 is a schematic diagram of a micromechanical film structure in an eighth embodiment of the present invention;

[0028] Fig. 9 is a schematic diagram of a micromechanical film structure in a ninth embodiment of the present invention;

[0029] Fig.10 is a schematic diagram of a micromechanical film structure in a tenth embodiment of the present invention;

[0030] Fig.11 FIG. 1 is a schematic diagram of a micromechanical film structure in the eleventh embodiment of the present invention.

[0031] Reference numerals:

[0032] 100. Micromechanical thin film structures;

[0033] 10. substrate; 20. anchor seat;

[0034] 30. Thin film component; 31. Hole portion; 311. Hole unit; 312. Through hole; 32. Mass component; 33. Beam body component. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0037] In addition, features defined as “first” or “second” may explicitly or implicitly include one or more such features, and are used to distinguish and describe features, without any distinction in order or importance.

[0038] In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] The micromechanical thin film structure 100 according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0041] like Figure 1 As shown, a micro-mechanical thin film structure 100 according to an embodiment of the present invention includes: a substrate 10 , an anchor seat 20 , and a thin film member 30 .

[0042] The anchor seat 20 is disposed on the substrate 10. The material of the substrate 10 includes but is not limited to silicon, glass, quartz and the like.

[0043] The film member 30 is connected to the anchor seat 20. The film member 30 has a set direction away from the anchor seat 20 and multiple effective widths sequentially arranged along the set direction. The effective width is the cross-sectional width of the film member 30 on a cross-sectional plane perpendicular to the set direction or the sum of the cross-sectional widths. The multiple effective widths gradually decrease along the set direction. It should be noted that the farther away from the anchor seat 20, the longer the force arm, and the easier it is to deform. The present invention designs the effective width of the film member 30 so that the effective width of the film member 30 away from the anchor seat 20 is reduced, the magnitude of the electrostatic force it is subjected to is reduced, and the stress is uniformed.

[0044] When the film member 30 has a hole portion 31 , the film member 30 has multiple cross-sectional widths on a cross-sectional plane perpendicular to a set direction. It can be understood that the hole portion 31 divides the cross section into multiple sections, and the effective width is the sum of the multiple cross-sectional widths.

[0045] For example, the anchor seat 20 is at the left end of the film member 30, and the direction is set to the left and right direction. The width of the film member 30 refers to the size of the film member 30 in the front and rear direction. The film member 30 has multiple effective widths in the left and right direction. The effective width close to the anchor seat 20 is large, and the effective width away from the anchor seat 20 is small, so that the electrostatic force on the part away from the anchor seat 20 is smaller, and the stress on the entire film member 30 is more uniform.

[0046] According to the micromechanical film structure 100 of the embodiment of the present invention, the effective width of the film member 30 is gradually reduced along a set direction, so that the stress on the film member 30 is evenly distributed, and stress concentration points are eliminated, thereby reducing fatigue, creep, plastic deformation and other phenomena and improving reliability.

[0047] like Figures 1 to 4 As shown, in some embodiments, a hole portion 31 is provided on the film member 30, and the cross-section passes through the hole portion 31 so that at least two cross-sections are formed on the film member 30, and the effective width is the sum of the widths of at least two cross-sections, so that the effective width can fully represent the width of the film member 30 on the cross-section, and it is convenient to set the stress on the film member 30. For example, two cross-sections are formed on the film member 30, and the two cross-sections are arranged front to back, and the effective width is the width of the front cross-section plus the width of the rear cross-section; or, three cross-sections are formed on the film member 30, and the three cross-sections are arranged front, middle and rear, and the effective width is the width of the front cross-section plus the width of the middle cross-section plus the width of the rear cross-section. Of course, there can be more cross-sections, such as four, five, etc., and the effect is the same as that of two cross-sections and three cross-sections, which will not be repeated here.

[0048] like Figure 1 to Figure 2 As shown, further, the hole portion 31 includes a plurality of hole units 311, and the plurality of hole units 311 are arranged at intervals along a set direction. By arranging the plurality of hole units 311 at intervals along the set direction, it is convenient to process the hole portion 31. For example, the set direction is the left-right direction, and the hole portion 31 includes five hole units 311, and the five hole units 311 are arranged at intervals from left to right in sequence. Of course, the hole portion 31 can also include two hole units 311, three hole units 311, four hole units 311, or even more hole units 311, all of which are possible, and the specific effects are the same as above, which will not be repeated here.

[0049] like Figure 1As shown, further, each hole unit 311 includes at least one through hole 312, and the distribution of the through holes 312 of the multiple hole units 311 obeys the Cantor set. By setting the distribution of the through holes 312 of the multiple hole units 311 to obey the Cantor set, the stress uniformity effect is further improved and manufacturing is convenient.

[0050] Among them, the Cantor set can be a Cantor trisection set or a generalized Cantor set, which is not limited here; at the same time, the through holes 312 of multiple hole units 311 can be the first few items that obey the Cantor set, or the middle items that obey the Cantor set. For example, five hole units 311 are arranged from left to right on the thin film 30. Counting from left to right, the first hole unit 311 includes sixteen through holes 312, the second hole unit 311 includes eight through holes 312, the third hole unit 311 includes four through holes 312, the fourth hole unit 311 includes two through holes 312, and the fifth hole unit 311 includes one through hole 312. The through holes 312 obey the first five items of the Cantor set. Of course, four hole units 311 can be set from left to right on the thin film 30. From left to right, the first hole unit 311 includes sixteen through holes 312, the second hole unit 311 includes eight through holes 312, the third hole unit 311 includes four through holes 312, and the fourth hole unit 311 includes two through holes 312. The through holes 312 obey the middle four terms of the Cantor set. The thin film 30 can also be set as through holes 312 in other cases, and the setting method is similar to the above method, which will not be repeated here.

[0051] like Figure 2 As shown, in some specific embodiments, the widths of the plurality of hole units 311 arranged along the set direction gradually increase, and the uniform stress is achieved by gradually increasing the widths of the plurality of hole units 311 along the set direction. For example, the set direction is the left-right direction, from left to right, and five hole units 311 are arranged on the film member 30, and the widths of the five hole units 311 gradually increase from left to right.

[0052] like Figure 2 As shown, specifically, the widths of the plurality of hole units 311 follow a numerical sequence, thereby achieving a uniform stress effect on the film member 30 .

[0053] Optionally, the sequence of the sequence is any one of a geometric sequence, an arithmetic sequence, a difference sequence and a power sequence. For example, the sequence is a geometric sequence; or, the sequence is an arithmetic sequence; or, the sequence is a difference sequence; or, the sequence is a power sequence; of course, the sequence can also be other sequences, which will not be described here.

[0054] like Figure 3 , Figure 4As shown, in some embodiments, the hole portion 31 extends along a set direction, and the width of the hole portion 31 gradually increases along the set direction, and the effect of uniform stress on the film member 30 is achieved by setting the width of the hole portion 31 to gradually increase along the set direction. For example, the set direction is the left-right direction, the hole portion 31 extends to the right, and the width of the hole portion 31 gradually increases from left to right.

[0055] like Figure 3 , Figure 4 As shown, specifically, the hole walls of the hole portion 31 on both sides of the set direction are arc-shaped transitions or step transitions, and the arc-shaped transitions or step transitions are provided to facilitate processing of the hole portion 31. For example, the set direction is the left-right direction, the hole walls of the hole portion 31 on both sides of the left-right direction are the front and rear hole walls, the front and rear hole walls are arc-shaped transitions, and the width of the hole portion 31 changes gradually in the left-right direction; or the front and rear hole walls are step transitions, and the width of the hole portion 31 changes step by step in the left-right direction.

[0056] like Figure 5 , Figure 6 As shown, in some embodiments, the film member 30 is constructed so that the width of the film member 30 gradually decreases along a set direction. By constructing the film member 30 so that its width gradually decreases along a set direction, the portion of the film member 30 away from the anchor seat 20 is subjected to a smaller electrostatic force.

[0057] like Figure 5 , Figure 6 As shown, specifically, the ends of the film member 30 located on both sides of the set direction are arc-shaped transitions or step transitions. For example, the set direction is the left-right direction, the ends of the film member 30 located on both sides of the left-right direction are the front and rear ends, the front and rear ends are arc-shaped transitions, and the width of the film member 30 changes gradually in the left-right direction; or the front and rear ends are step transitions, and the width of the film member 30 changes step by step in the left-right direction.

[0058] like Figure 7 As shown, in some embodiments, the film member 30 includes a mass member 32 and at least two beam members 33, one end of each beam member 33 is connected to the anchor seat 20 and the other end is connected to the mass member 32, and the width of each beam member 33 gradually decreases along the set direction. By setting at least two beam members 33 to jointly bear the mass block, the pressure on a single beam member 33 is reduced. For example, the set direction is the left-right direction, there are two beam members 33, the two beam members 33 are distributed front and back, the left end of each beam member 33 is connected to the anchor seat 20, and the right end of each beam member 33 is connected to the same mass block. Alternatively, there are three beam members 33, the three beam members 33 are distributed front, middle and back, the left end of each beam member 33 is connected to the anchor seat 20, and the right end of each beam member 33 is connected to the same mass block. Of course, there can be more beam members 33, such as four, five, etc., which will not be repeated here.

[0059] like Figures 1 to 8 As shown, in some embodiments, the film component 30 is constructed as a beam or a film. By constructing the film component 30 as a beam or a film, it is used for structural driving and signal sensing, and the effect of the micromechanical film structure 100 is fully utilized. For example, the film component 30 is constructed as a beam. It can be understood that the beam of the MEMS device is relatively thin and small, and can be used as a long strip of film component 30, and the direction is set to the length direction of the beam; or the film component 30 is constructed as a film, and the direction is set to the radial direction. Among them, the film can be a circular film or a polygonal film, which will not be repeated here.

[0060] like Figures 9 to 11 As shown, specifically, the beam body is a single-end fixed beam or a double-end fixed beam, wherein when the beam body is a double-end fixed beam, the set direction includes a first direction and a second direction in opposite directions, and the multiple effective widths include two groups, one of the two groups of effective widths is set along the first direction, and the other group is set along the second direction. By setting the first direction and the second direction, the effect of uniform stress on the double-end fixed beam is achieved, and the scope of use is expanded. For example, the set direction is the left-right direction, the first direction is the direction from left to right, and the second direction is the direction from right to left. One of the two groups of effective widths gradually decreases from left to right, and the other group of effective widths gradually decreases from right to left. Of course, the beam body can also be a three-end fixed beam, a four-end fixed beam, or a multi-end fixed beam, which will not be elaborated here.

[0061] Combine the following Figures 1 to 11 , describing a specific embodiment of the micromechanical thin film structure 100 of the present invention.

[0062] A micromechanical thin film structure 100 includes a substrate 10 , an anchor seat 20 and a thin film member 30 .

[0063] The material of the substrate 10 is silicon. The anchor seat 20 is arranged on the substrate 10. The thin film member 30 is a single-end fixed beam, the left end of the thin film member 30 is connected to the anchor seat 20, and the thin film member 30 is provided with a hole portion 31, the hole portion 31 includes five hole units 311, and the five hole units 311 are arranged from left to right. The first hole unit 311 includes sixteen through holes 312, the second hole unit 311 includes eight through holes 312, the third hole unit 311 includes four through holes 312, the fourth hole unit 311 includes two through holes 312, and the fifth hole unit 311 includes one through hole 312. The number and width of the through holes 312 meet the first five items of the Cantor set.

[0064] Other structures and operations of the micro-mechanical thin film structure 100 according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0065] In the description of this specification, the description with reference to the terms "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0066] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A micromechanical thin film structure of a MEMS device, characterized in that: include: substrate; An anchor seat, the anchor seat is arranged on the substrate; A film member, the film member is connected to the anchor seat, the film member has a set direction away from the anchor seat and a plurality of effective widths sequentially arranged along the set direction, the effective width is a cross-sectional width of the film member on a cross-sectional plane perpendicular to the set direction or a sum of cross-sectional widths, and the plurality of effective widths gradually decrease along the set direction; a hole portion is provided on the film member, the cross-sectional plane passes through the hole portion so that at least two cross sections are formed on the film member, and the effective width is the sum of widths of at least two cross sections; The hole portion includes a plurality of hole units, and the plurality of hole units are arranged at intervals along the set direction; each of the hole units includes at least one through hole, and the distribution of the through holes of the plurality of hole units obeys the Cantor set; or the hole portion includes a plurality of hole units, and the plurality of hole units are arranged at intervals along the set direction; the widths of the plurality of hole units arranged along the set direction gradually increase; the widths of the plurality of hole units obey a number sequence, and the number sequence of the number sequence is any one of a geometric sequence, an arithmetic sequence, a difference ratio sequence, and a power sequence; The hole portion extends along the set direction, and the width of the hole portion gradually increases along the set direction. The hole walls of the hole portion located on both sides of the set direction are arc-shaped transitions or step transitions.

2. The micromechanical thin film structure of the MEMS device according to claim 1, characterized in that: The film element is configured as a beam body or a film.

3. The micromechanical thin film structure of the MEMS device according to claim 2, characterized in that: The beam body is a single-end clamped beam or a double-end clamped beam, wherein when the beam body is a double-end clamped beam, the set direction includes a first direction and a second direction in opposite directions, and the multiple effective widths include two groups, one of the two groups of effective widths is set along the first direction, and the other group is set along the second direction.

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