Gas-driven single vertical beam supported MEMS micromirror structure and processing technology thereof
The MEMS micromirror structure is supported by gas-driven single vertical beam, and a large torsion angle is achieved using gas channels and support beams, solving the problems in the high voltage and high temperature environments in the existing technology, and achieving the effect of simple structure, high temperature resistance and low cost.
Patent Information
- Application Number
- CN202411825646.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-03-28
AI Technical Summary
Existing MEMS micromirrors require higher voltage or current when a larger torsion angle is required, which increases manufacturing difficulty and manufacturing cost, and is not suitable for working in high temperature environments.
The MEMS micromirror structure is adopted to support the MEMS micromirror structure, and the torsion of the reflective mirror surface of the micromirror is driven through the gas channel. The support beam and limit structure are used to achieve a large torsion angle, and work in a high-temperature environment.
The large torsion angle of the mirror reflecting micromirror is realized, which reduces the demand for on-chip driving circuits, simplifies the structure, improves high temperature resistance, and reduces manufacturing costs.
Smart Images
Figure CN119717254A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of micromirror technology, and in particular to a gas-driven single vertical beam supported MEMS micromirror structure and a processing technology thereof. Background Art
[0002] MEMS micromirrors (or scanning mirrors) are key laser components essential for laser applications, and their application areas have penetrated into consumer electronics, medical treatment, military defense, communications, etc. MEMS micromirrors are divided into four types of electrostatic drives according to the principle: electrostatic drive, electromagnetic drive, electrothermal drive, and piezoelectric drive. The first two technologies are relatively mature and have wider applications. For example, the MEMS micromirror array in Texas Instruments' DLP uses an electrostatic drive mode. Therefore, these micromirrors need to process the drive circuit on the chip. If the micromirror requires a larger torsion angle, a larger voltage or current is required, but this will increase the difficulty of manufacturing, increase manufacturing costs, and make the structure complex, and it cannot work in high temperature environments. In some cases where the micromirror does not require high precision or is not suitable for circuit operation (such as high temperature), the use of a drive circuit will become unsuitable. Summary of the invention
[0003] The purpose of the present invention is to provide a gas-driven single vertical beam supported MEMS micromirror structure and a processing technology thereof, so as to solve the problems raised in the above-mentioned background technology.
[0004] To achieve the above object, the present invention provides the following technical solutions:
[0005] A gas-driven single vertical beam supporting a MEMS micromirror structure, comprising a first silicon wafer, a second silicon wafer, a third silicon wafer, a micromirror reflective surface and a supporting beam;
[0006] The first silicon wafer is bonded to one side of the second silicon wafer;
[0007] The second silicon wafer is provided with an active cavity for the micromirror to reflect the mirror surface;
[0008] The third silicon wafer is bonded to the other side of the second silicon wafer, and the third silicon wafer and the second silicon wafer have gas channels connected to the active cavity;
[0009] One end of the support beam is connected to the reflective surface of the micromirror, and the other end of the support beam is connected to the bottom of the cavity.
[0010] Furthermore, the gas channel is used for external gas, and the external gas enters into the active cavity to drive the micromirror reflective surface to twist with the support beam as the support point.
[0011] Furthermore, the second silicon wafer has a limiting structure for limiting the torsion of the micromirror reflective surface.
[0012] Furthermore, the limiting structure includes a limiting groove opened on the movable cavity, and the micromirror reflector surface has a limiting beam, and the limiting beam is located in the limiting groove and contacts the limiting groove for limiting cooperation.
[0013] Furthermore, the gas channels on the third silicon wafer are distributed laterally along the third silicon wafer, and the gas channels on the second silicon wafer are distributed longitudinally along the second silicon wafer and are located at the bottom of the active cavity.
[0014] Furthermore, the first silicon wafer is based on an SOI silicon wafer, and the second silicon wafer and the third silicon wafer are based on a DSP silicon wafer.
[0015] Furthermore, the support beam has resilience.
[0016] To achieve the above object, the present invention provides the following technical solutions:
[0017] A gas-driven single vertical beam supporting MEMS micromirror structure processing technology, comprising the gas-driven single vertical beam supporting MEMS micromirror structure, the micromirror structure processing steps are as follows:
[0018] Step 1, etching a micromirror reflective surface on a first silicon wafer;
[0019] Step 2, etching the active cavity and the support beam located in the active cavity on the second silicon wafer, and etching a gas channel on the active cavity at the same time;
[0020] Step 3, etching a gas channel on the third silicon wafer;
[0021] Step 4: Bonding the second silicon wafer etched in step 2 and the third silicon wafer etched in step 3 as substrate silicon, and connecting the gas channel on the active cavity with the gas channel on the third silicon wafer;
[0022] Step 5: Bond the first silicon wafer etched in step 1 to the substrate silicon so that the micromirror reflective surface is bonded to the support beam, and obtain the desired micromirror structure after etching.
[0023] Furthermore, in step 2, a limiting groove is etched on the active cavity. In step 1, a limiting beam is reserved on the micromirror reflecting surface when the micromirror reflecting surface is etched on the first silicon wafer, and the limiting beam can contact and cooperate with the limiting groove.
[0024] Furthermore, the micro-etching in step five includes: etching the substrate silicon and the first silicon wafer, releasing the micro-mirror reflective surface of the first silicon wafer to bond with the support beam.
[0025] Compared with the prior art, the present invention has the following beneficial effects:
[0026] The present invention has a gas channel and is driven by gas, so that the micromirror reflective surface has a larger torsion angle. Since it is supported by a single support beam, it can rotate in all directions, and there is a limit structure to ensure the protection of the micromirror reflective surface. By adopting the gas channel air intake control method, a simple and reliable structure is achieved, which is driven by an external gas source and resistant to high temperatures. Since the gas source pressure and flow rate of the gas are controllable, a larger torsion angle of the micromirror reflective surface can be achieved. The previous electrostatic drive has been solved. If a larger torsion angle is to be achieved, a higher voltage needs to be loaded, resulting in the disadvantages of poor safety and economy. Therefore, the present invention mainly eliminates the driving circuit on the chip, reduces the processing difficulty, saves costs, relies on external gas / gas source drive, and has greater flexibility. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 It is a structural schematic diagram of the present invention.
[0028] Figure 2 For the present invention Figure 1 Middle AA section view.
[0029] Figure 3 This is a schematic diagram of the first silicon wafer after etching of the present invention.
[0030] Figure 4 This is a schematic diagram of the second silicon wafer after etching according to the present invention.
[0031] Figure 5 This is a schematic diagram of the third silicon wafer after etching according to the present invention.
[0032] Figure 6 This is a schematic diagram of bonding the etched second silicon wafer and the third silicon wafer to form a substrate silicon according to the present invention.
[0033] Figure 7 The schematic diagram of bonding the etched first silicon wafer to the substrate silicon is shown in the present invention.
[0034] Figure 8 For the present invention Figure 7 Schematic diagram of etching.
[0035] In the figure: 1-first silicon wafer, 2-second silicon wafer, 3-third silicon wafer, 4-micromirror reflective surface, 5-limiting beam, 6-active cavity, 7-limiting groove, 8-gas channel, 9-support beam. DETAILED DESCRIPTION
[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0037] In the description of the present invention, it should be noted that the terms "upper end", "lower end", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.
[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "sleeved", "connected", "connected", etc. should be understood in a broad sense. For example, "connected" 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 those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0039] See also Figures 1 to 8 , the present invention provides a technical solution:
[0040] A gas-driven single vertical beam supported MEMS micromirror structure, comprising a first silicon wafer 1, a second silicon wafer 2, a third silicon wafer 3, a micromirror reflective surface 4 and a supporting beam 9;
[0041] The first silicon wafer 1 is a SOI silicon wafer, and the second silicon wafer 2 and the third silicon wafer 3 are both DSP silicon wafers.
[0042] The first silicon wafer 1 is bonded to one side of the second silicon wafer 2;
[0043] The second silicon wafer 2 is provided with an active cavity 6 for the movement of the micromirror reflective surface 4;
[0044] The third silicon wafer 3 is bonded to the other side of the second silicon wafer 2, and the third silicon wafer 3 and the second silicon wafer 2 have a gas channel 8 connected to the active cavity 6;
[0045] One end of the support beam 9 is connected to the micromirror reflective surface 4 , and the other end of the support beam 9 is connected to the bottom of the cavity 6 .
[0046] Specifically, the gas channel 8 is used for external gas, and the external gas enters into the active cavity 6 to drive the micromirror reflective surface 4 to twist with the support beam 9 as the support point.
[0047] Specifically, the second silicon wafer 2 has a limiting structure for limiting the twisting of the micromirror reflective surface 4 .
[0048] Specifically, the limiting structure includes a limiting groove 7 provided on the movable cavity 6 , and the micromirror reflective surface 4 has a limiting beam 5 , and the limiting beam 5 is located in the limiting groove 7 and contacts and cooperates with the limiting groove 7 for limiting purpose.
[0049] Specifically, the gas channels 8 on the third silicon wafer 3 are distributed laterally along the third silicon wafer 3 , and the gas channels 8 on the second silicon wafer 2 are distributed longitudinally along the second silicon wafer 2 and are located at the bottom of the active cavity 6 .
[0050] The present invention, as Figures 4 to 6 As shown, the second silicon wafer 2 is etched to form an active cavity 6, and then a gas channel 8 is etched at the bottom of the active cavity 6. The gas channel 8 at this location is distributed longitudinally along the second silicon wafer 2 or the active cavity 6. Then, the gas channel 8 is etched on the third silicon wafer 3, and the gas channel 8 at this location is distributed transversely along the third silicon wafer 3. Then, the etched second silicon wafer 2 is bonded to the third silicon wafer 3, so that the gas channel 8 of the third silicon wafer 3 is connected to the gas channel 8 of the second silicon wafer 2 accordingly.
[0051] The present invention, by Figure 5 It can be seen that the gas channels 8 etched on the third silicon wafer 3 are distributed along the surface of the third silicon wafer 3, that is, the gas channels 8 at this location are actually grooves on the third silicon wafer 3. Figure 6 It can be seen that after the third silicon wafer 3 is bonded to the second silicon wafer 2 , one surface of the second silicon wafer 2 covers the groove to form a gas channel 8 .
[0052] In the present invention, there are four gas channels 8, which are respectively located around the micromirror structure. Of course, the specific number of the gas channels 8 can also be flexibly set according to actual usage.
[0053] In the present invention, the external gas is connected to one of the gas channels 8, and then the gas enters the active cavity 6 through the gas channel 8, which will push the micromirror reflective surface 4 to twist with the support beam 9 as the support point, thereby achieving the purpose of controlling the output deflection angle of the micromirror reflective surface 4.
[0054] In the present invention, by adopting the air intake control mode of the gas channel 8, a simple and reliable structure is achieved, which is driven by an external gas source and resistant to high temperature. Since the gas source pressure and flow rate of the gas are controllable, a larger torsion angle of the micromirror reflective surface 4 can be achieved. This solves the problem of the previous electrostatic drive, which requires a higher voltage to be loaded if a larger torsion angle is to be achieved, resulting in the disadvantages of poor safety and economy.
[0055] In the present invention, an elastic support beam 9 is used to support the micromirror reflective surface 4, and the micromirror reflective surface 4 can be twisted in the vertical (towards all directions) with the support beam 9 as a support point to achieve a larger twisting angle.
[0056] In the present invention, when the micromirror reflecting surface 4 is twisted, the micromirror reflecting surface 4 is restricted by a limiting structure to avoid the micromirror reflecting surface 4 and the supporting beam 9 from being broken due to excessive gas source pressure. This can enable the micromirror reflecting surface 4 to achieve a larger twisting angle and ensure the protection of the micromirror reflecting surface 4.
[0057] In the present invention, there is a gap between the micromirror reflective surface 4 and the active cavity 6, and the gap is mainly used for gas outflow, because the gas needs to be blown continuously in the gas channel 8 to keep the micromirror reflective surface 4 twisted with the support beam 9 as the support point. If there is no gap, the gas (active cavity 6) cannot be discharged, the internal pressure increases, and there is no continuous airflow, and the micromirror reflective surface 4 cannot be twisted. There are four gas channels 8 mainly to consider that the micromirror reflective surface 4 can be twisted in at least four directions. Of course, multiple gas channels can be ventilated at the same time to achieve twisting at complex angles.
[0058] The present invention also provides a processing technology for a gas-driven single vertical beam supporting a MEMS micromirror structure, comprising the gas-driven single vertical beam supporting a MEMS micromirror structure, wherein the steps of processing the micromirror structure are as follows:
[0059] Step 1, etching a micromirror reflective surface 4 on the first silicon wafer 1;
[0060] Step 2: etching the active cavity 6 and the support beam 9 located in the active cavity 6 on the second silicon wafer 2, and etching a gas channel 8 on the active cavity 6;
[0061] Step 3, etching a gas channel 8 on the third silicon wafer 3;
[0062] Step 4: Bond the second silicon wafer 2 etched in step 2 and the third silicon wafer 3 etched in step 3 as substrate silicon, and connect the gas channel 8 on the active cavity 6 with the gas channel 8 on the third silicon wafer 3;
[0063] Step 5: Bond the first silicon wafer 1 etched in step 1 to the substrate silicon in step 4, so that the micromirror reflective surface 4 is bonded to the support beam 9, and the desired micromirror structure is obtained after etching.
[0064] Specifically, in step 2, a limiting groove 7 is etched on the active cavity 6. In step 1, when the micromirror reflective surface 4 is etched on the first silicon wafer 1, a limiting beam 5 is reserved on the micromirror reflective surface 4, and the limiting beam 5 can contact and cooperate with the limiting groove 7 for limiting.
[0065] Specifically, the micro-etching in step five includes: etching the substrate silicon and the first silicon wafer 1 in step four, and releasing the micro-mirror reflective surface 4 of the first silicon wafer 1 to bond with the support beam 9 .
[0066] It should be noted that if Figure 3 , Figure 6 As shown, when the first silicon wafer 1 after etching is bonded to the substrate silicon obtained in step 4, the first silicon wafer 1 is turned upside down to bond to the substrate silicon, that is, Figure 7 Status shown.
[0067] The present invention has a gas channel 8 and is gas driven, which can make the micromirror reflective surface 4 have a larger torsion angle. Since it is supported by a single support beam 9 (vertical beam), it can rotate in all directions and has a limit structure to ensure the protection of the micromirror reflective surface 4.
[0068] The present invention has a simple structure, does not require a driving circuit on the chip, can achieve a larger torsion angle, and can operate under high temperature conditions.
[0069] The present invention, the undescribed parts are prior art.
[0070] Although 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 appended claims and their equivalents.
Claims
1. A gas-driven single vertical beam supporting MEMS micromirror structure, characterized in that: It comprises a first silicon chip (1), a second silicon chip (2), a third silicon chip (3), a micromirror reflective surface (4) and a support beam (9); The first silicon wafer (1) is bonded to one side of the second silicon wafer (2); The second silicon wafer (2) is provided with an active cavity (6) for the movement of the micromirror reflective surface (4); The third silicon wafer (3) is bonded to the other side of the second silicon wafer (2), and the third silicon wafer (3) and the second silicon wafer (2) are provided with a gas channel (8) communicating with the active cavity (6); One end of the support beam (9) is connected to the micromirror reflective surface (4), and the other end of the support beam (9) is connected to the bottom of the cavity (6).
2. A gas driven single vertical beam supported MEMS micromirror structure as claimed in claim 1, characterized in that: The gas channel (8) is used to connect external gas, and the external gas enters the active cavity (6) and is used to drive the micromirror reflective surface (4) to twist with the support beam (9) as a support point.
3. A gas driven single vertical beam supporting MEMS micromirror structure as claimed in claim 1, characterized in that: The second silicon chip (2) has a limiting structure for limiting the twisting of the micromirror reflective surface (4).
4. A gas driven single vertical beam supported MEMS micromirror structure as claimed in claim 3, characterized in that: The limiting structure comprises a limiting groove (7) provided on the movable cavity (6); the micromirror reflective surface (4) comprises a limiting beam (5); the limiting beam (5) is located in the limiting groove (7) and contacts and cooperates with the limiting groove (7) for limiting purpose.
5. A gas driven single vertical beam supported MEMS micromirror structure as claimed in claim 1, characterized in that: The gas channels (8) on the third silicon wafer (3) are distributed laterally along the third silicon wafer (3), and the gas channels (8) on the second silicon wafer (2) are distributed longitudinally along the second silicon wafer (2) and are located at the bottom of the active cavity (6).
6. A gas driven single vertical beam supported MEMS micromirror structure as claimed in claim 1, characterized in that: The first silicon wafer (1) is based on an SOI silicon wafer, and the second silicon wafer (2) and the third silicon wafer (3) are based on a DSP silicon wafer.
7. A gas driven single vertical beam supported MEMS micromirror structure as claimed in claim 1, characterized in that: The support beam (9) has resilience.
8. A processing technology for a gas-driven single vertical beam supporting a MEMS micromirror structure, characterized in that: It comprises a gas driven single vertical beam supporting MEMS micromirror structure as claimed in any one of claims 1 to 7, and the steps of processing the micromirror structure are as follows: Step 1: etching a micromirror reflective surface (4) on a first silicon wafer (1); Step 2: etching the active cavity (6) and the support beam (9) located in the active cavity (6) on the second silicon wafer (2), and etching a gas channel (8) on the active cavity (6); Step 3: etching a gas channel (8) on the third silicon wafer (3); Step 4: Bonding the second silicon wafer (2) etched in step 2 and the third silicon wafer (3) etched in step 3 as substrate silicon, and connecting the gas channel (8) on the active cavity (6) with the gas channel (8) on the third silicon wafer (3); Step 5: Bonding the first silicon wafer (1) etched in step 1 to the substrate silicon, so that the micromirror reflective surface (4) is bonded to the support beam (9), and the desired micromirror structure is obtained after etching.
9. A gas driven single vertical beam supporting MEMS micromirror structure processing technology as claimed in claim 8, characterized in that: In step 2, a limiting groove (7) is etched on the active cavity (6); in step 1, when a micromirror reflecting mirror surface (4) is etched on the first silicon wafer (1), a limiting beam (5) is reserved on the micromirror reflecting mirror surface (4); the limiting beam (5) can be in contact with the limiting groove (7) for limiting cooperation.
10. The processing technology of a gas-driven single vertical beam supporting a MEMS micromirror structure as claimed in claim 8, characterized in that: The micro-etching in step five includes: etching the substrate silicon and the first silicon wafer (1), releasing the micro-mirror reflective mirror surface (4) of the first silicon wafer (1) to bond with the support beam (9).