Method for manufacturing at least one first and second micro-mirror device

Abstract

The invention relates to a method for producing at least one first (205) and second micromirror device (206). Here, a silicon wafer (100), in particular plate-shaped, having a front side (110) and a back side (120) is provided. Then, a silicon oxide layer (130) is applied to at least the front side (110) of the silicon wafer (100, 101). Subsequently, the silicon oxide layer (130) is removed such that at least one first separation region (131) and at least one second separation region (132) of the silicon oxide layer (130) are produced, wherein the first (131) and second separation region (132) of the silicon oxide layer (130) are arranged spatially separated from one another along a separation plane (140). Then, a silicon layer (150) is applied to the front side (110) of the silicon wafer (101) and the silicon oxide layer (130). Subsequently, an etching mask (180) is applied (70) to the back side (120) of the silicon wafer (100), wherein the etching mask (180) has a first opening (190) along the separation plane (140) of the first (131) and second separation region (132) of the silicon oxide layer (130). Subsequently, the silicon layer (150, 350) and the silicon wafer (100, 101) are removed (80) by means of an etching method in accordance with the etching mask (180) on the back side (120) of the silicon wafer (100, 101) and in accordance with the silicon oxide layer (130) of the silicon wafer (100), in particular the first (131) and second separation region (132) of the silicon oxide layer (130), such that at least one first (205) and second micromirror device (206) are produced.

Description

Technical Field

[0001] This invention relates to a method for manufacturing at least one first and second micromirror device. Furthermore, this invention relates to a first and / or second micromirror device manufactured by the method described herein, and particularly to a first and / or second micromirror device having a first and / or second mirror plate, each having a polycrystalline silicon layer, manufactured by the method according to the invention. Background Technology

[0002] A method for manufacturing micromirrors is known from document WO2014 / 064606A1. A silicon oxide wafer is used, which is first separated along a separation plane by wet etching in one method step, and the mirror plate of the micromirror is separated in a separate method step.

[0003] Based on the prior art, the objective of this invention is to provide a simplified method for manufacturing micromirror devices. Summary of the Invention

[0004] To address this task, a method for manufacturing at least one first and a second micromirror device is proposed. "Micromirror device" here specifically refers to a mechanical micromirror, i.e., a micromirror not yet connected to a drive unit of the micromirror. In one method step, a silicon wafer, particularly plate-shaped, having a front side and a back side, is provided. "Front side of the silicon wafer" specifically refers to the side oriented in the direction of the reflective surface of the micromirror device for incident light beams in the completed micromirror device. In a further method step, a silicon oxide layer is thermally applied to at least the front side of the silicon wafer, particularly with a layer thickness in the range of 1 μm to 3 μm. Specifically, a silicon oxide layer with a layer thickness of 2 μm is applied. In a subsequent method step, the silicon oxide layer is removed, particularly down to the outer surface of the silicon wafer, such that at least one first separation region and at least one second separation region of the silicon oxide layer are formed. Here, the first and second separation regions of the silicon oxide layer are spatially separated from each other along a separation plane. Accordingly, no material cohesion (Zusammenhalt) exists between the first and second separation regions of the silicon oxide layer. The separation plane is in particular a plane arranged substantially perpendicular to the outer surface of the silicon wafer. In a further method step, a silicon layer, in particular a polycrystalline silicon layer having a layer thickness in the range of 5 μm to 50 μm, is applied to the front side of the silicon wafer and the silicon oxide layer, particularly to the first and second separation regions of the silicon oxide layer. The silicon layer is in direct contact with the front side of the silicon wafer, particularly the outer surface of the front side of the silicon wafer, and with the silicon oxide layer, particularly the outer surface of the silicon oxide layer. Further, an etching mask is applied to the back side of the silicon wafer, wherein the etching mask has a first opening along the separation plane of the first and second separation regions of the silicon oxide layer. The etching mask is in particular a hard mask or a resist mask. As an etching mask, another silicon oxide layer is applied to the back side of the silicon wafer. In a further method step, the silicon layer, particularly a portion of the silicon layer, and the silicon wafer, particularly a portion of the silicon wafer, are then removed by etching, based on an etching mask on the back side of the silicon wafer and based on the silicon oxide layer, particularly the first and second separation regions of the silicon oxide layer, thereby producing at least one first and second micromirror devices. The etching mask and the silicon oxide layer are used herein as layers to stop etching (etch stop layers). By using a pre-structured silicon oxide wafer within the method described herein, it is possible to implement the last described method step in a single method step, in which the micromirror devices are separated from each other. Preferably, by removing the silicon layer, particularly a portion of the silicon layer, by etching, at least one first separation region and a second separation region of the silicon layer are produced.Here, the first and second separation regions of the silicon layer are spatially arranged separately from each other along the separation plane, thus forming the first mirror plate of the first micromirror device and the second mirror plate of the second micromirror device. The first mirror plate has the first separation region of the silicon layer, and the second mirror plate has the second separation region of the silicon layer. The reflective surface of such a mirror plate is later used in a micromirror to deflect the incident light beam, for example, to project an image. Such a mirror plate has, for example, 50 mm. 2 Up to 200mm 2 The reflective area. The mirror plate has, for example, a circular, elliptical, or rectangular shape. In this context, the first and second separation regions of the silicon oxide layer are preferably produced according to the required corresponding dimensions and corresponding shapes (especially circular and / or elliptical and / or rectangular shapes) of the first mirror plate of the first micromirror device and the second mirror plate of the second micromirror device. More preferably, at least one first separation region and a second separation region of the silicon wafer are produced by removing the silicon wafer, especially a portion of the silicon wafer, by means of an etching method. Here, the first and second separation regions of the silicon wafer are arranged spatially, separated from each other along the separation plane. Thus, a first reinforcement structure (Versteifungsstruktur) of the first micromirror device and a second reinforcement structure of the second micromirror device are produced, the first reinforcement structure having a first separation region of the silicon wafer and a first separation region of the silicon oxide layer, and the second reinforcement structure having a second separation region of the silicon wafer and a second separation region of the silicon oxide layer. Such a reinforcement structure is used to connect the mirror plate to the later part of the micromirror. The drive unit is connected. Here, on the one hand, the reinforcement structure should have the lowest possible weight to achieve high mobility of the micromirror; on the other hand, the reinforcement structure of the mirror plate must provide the necessary stability. In this context, the etching mask preferably also has at least one second opening, which is particularly used to separate the first reinforcement structure into a first separation region and a second separation region of the first reinforcement structure. Thus, the corresponding reinforcement structure can be constructed as at least two reinforcement struts (Versteifungsstreben) extending parallel to each other.

[0005] Preferably, plasma etching, especially DRIE etching, is used as the etching method. Alternatively, ion beam etching is used as the etching method. Thus, the reinforced structure of the mirror plate and the micromirror device can be produced in a single process step.

[0006] Preferably, at the start of the method, the silicon wafer is provided as a raw wafer with a thickness of substantially 300 to 400 μm. In this case, the raw wafer already has a thickness at the start of the method, and the hardening structure in the finished micromirror device should have this thickness as a target thickness to meet the requirements regarding weight and stability. Alternatively, at the start of the method, the silicon wafer is provided as a raw wafer with a thickness of substantially 725 μm. In this case, it is preferable to grind away the back side of the silicon wafer, particularly a polycrystalline silicon layer, in a further method step after applying a silicon layer, especially a polycrystalline silicon layer, to the front side of the silicon wafer and the silicon oxide layer, particularly until the target thickness of the silicon wafer is achieved. This target thickness corresponds particularly to a layer thickness in the range of 300 μm to 400 μm.

[0007] Preferably, a silicon oxide layer is additionally thermally applied to the back side of the silicon wafer. In this case, if the silicon wafer is provided as a raw wafer with a thickness of substantially 300 to 400 μm at the start of the method, the silicon oxide layer can be used, for example, as an etching mask on the back side.

[0008] Preferably, in a further method step, a first metal layer, particularly a first gold layer or a first aluminum layer, is applied to the silicon layer, particularly to the outer surface of the first separation region of the silicon layer. Further, a second metal layer, particularly a second gold layer or a second aluminum layer, is applied to the silicon layer, particularly to the outer surface of the second separation region of the silicon layer. This improves the reflectivity of the mirror plate of the corresponding micromirror device. Preferably, at least two markings are applied to the silicon layer to orient the first metal layer relative to the first separation region of the silicon oxide layer and to orient the second metal layer relative to at least the second separation region of the silicon oxide layer. Here, the at least two markings are etched, in particular, into the outer surface of the silicon layer. To apply the markings to the silicon layer in the correct position, an infrared measuring device is used, by which the structure of the first separation region and at least the second separation region of the silicon oxide layer buried within the layer stack can be detected. Then, the at least two markings are applied, in particular, to the edge regions of the layer stack. Thus, the metal layer on the front side of the silicon wafer can be oriented toward the structure of the first separation region and at least the second separation region of the silicon oxide layer buried in the layer structure.

[0009] Preferably, the outer surfaces of the silicon layer, especially the first separation region of the silicon layer and the second separation region of the silicon layer, are directly or indirectly connected to an adhesive tape, especially a single-sided adhesive tape. The adhesive tape, which can be configured as a blue tape, serves on the one hand to transport the manufactured first and second micromirror devices to their respective drive units, and on the other hand to stop the etching process in which a portion of the silicon layer and a portion of the silicon wafer are removed.

[0010] Preferably, in a further method step, the etching mask is removed. If the etching mask is a lacquer mask, it is removed, for example, by plasma stripping. In the case of a hard mask as the etching mask, it can be removed using an oxide etching process. If an oxide etching process is used, the exposed portion of the silicon oxide layer on the front side of the silicon wafer is also etched away. Therefore, the stress of the reinforcement structure on the mirror plate can be reduced.

[0011] Preferably, the silicon layer is applied in the form of a silicon, especially polycrystalline silicon, deposit on the front side of the silicon wafer and on the silicon oxide layer, especially on the first and second separation regions of the silicon oxide layer, and then a polishing step is performed.

[0012] Another subject of the present invention is a first and / or second micromirror device manufactured by the aforementioned method.

[0013] Another subject of the invention is a first and / or second micromirror device, which is manufactured, in particular, by means of the foregoing method and has first and / or second mirror plates, each having a polycrystalline silicon layer. In a silicon wafer serving as the raw wafer, the polycrystalline silicon layer can be applied to the outer surface of the silicon wafer. Such a polycrystalline silicon layer can be easily applied to any surface of the silicon wafer. Preferably, the polycrystalline silicon layer has a layer thickness in the range of 5 μm to 50 μm. More preferably, the polycrystalline silicon layer has a layer thickness of substantially 20 μm. Attached Figure Description

[0014] Figures 1a.1 to 1a.3 The method steps of a first embodiment of a method for manufacturing at least one first and second micromirror device are schematically shown.

[0015] Figures 1b.1 to 1b.4 The method steps of a second embodiment of a method for manufacturing at least one first and second micromirror device are schematically shown.

[0016] Figure 2 A first micromirror device is shown having a first and / or a second mirror plate, each having a polycrystalline silicon layer. Detailed Implementation

[0017] Figures 1a.1 to 1a.3The method steps of a first embodiment of a method for manufacturing at least one first and second micromirror device are schematically illustrated. Here, in the first method step 10, a silicon wafer 100, particularly plate-shaped, having a front side 110 and a back side 120, is provided. In the subsequent method step 20, a silicon oxide layer 130 is applied to the front side 110 of the silicon wafer 100, particularly with a layer thickness 135 of substantially 2 μm. In the subsequent method step 30, the silicon oxide layer 130 is removed, particularly down to the outer surface 111 of the silicon wafer 100, thereby creating a first separation region 131 and a second separation region 132 of the silicon oxide layer 130. Here, the first separation region 131 and the second separation region 132 of the silicon oxide layer 130 are spatially separated from each other along a separation plane 140. In subsequent method step 40, a silicon layer 150, particularly a silicon layer with a layer thickness 116 of substantially 20 μm, is applied to the front side 110 of the silicon wafer 100 and the first separation region 131 and the second separation region 132 of the silicon oxide layer 130. In this case, the silicon layer 150 is a polycrystalline silicon layer. In subsequent method step 70, an etching mask 180 is applied to the back side 120 of the silicon wafer 100. Here, the etching mask 180 has a first opening 190 along the separation plane 140. In this case, the etching mask 180 is a hard mask constructed from another silicon oxide layer 181 and applied to the back side 120 of the silicon wafer. In subsequent method step 80, the silicon layer 150, particularly a portion of the silicon layer 150, and the silicon wafer 100, particularly a portion of the silicon wafer 100, are removed by etching according to an etching mask 180 on the back side 120 of the silicon wafer 100 and according to a first separation region 131 and a second separation region 132 of the silicon oxide layer, thereby creating at least one first micromirror device 205 and a second micromirror device 206. Here, the first separation region 131 and the second separation region 132 of the silicon oxide layer 130 are configured as etch stop layers.

[0018] In the presented embodiment, at least one first separation region 200 and a second separation region 201 of the silicon layer 150 are generated by removing the silicon layer 150 by means of an etching method in method step 80. The first separation region 200 and the second separation region 201 of the silicon layer 150 are also spatially separated from each other along the separation plane 140. Thus, a first mirror plate 211 of the first micromirror device 205 and a second mirror plate 212 of the second micromirror device 206 are generated, the first mirror plate having the first separation region 200 of the silicon layer 150 and the second mirror plate having the second separation region 201 of the silicon layer 150.

[0019] Furthermore, in the presented embodiment, a first separation region and a second separation region of the silicon wafer 100 are generated by removing the silicon wafer 100 using an etching method in method step 80. Here, the first and second separation regions of the silicon wafer 100 are spatially separated from each other along the separation plane 140. Thus, a first reinforcement structure 195 of the first micromirror device 205 and a second reinforcement structure 196 of the second micromirror device 206 are generated. The first reinforcement structure has the first separation region of the silicon wafer 100 and a first separation region 131 of the silicon oxide layer 130, and the second reinforcement structure has the second separation region of the silicon wafer 100 and a second separation region 132 of the silicon oxide layer 130.

[0020] Furthermore, in the presented embodiment, the etching mask 180 has a second opening 221, a third opening 222, a fourth opening 223, and a fifth opening 224. These openings are configured to divide the first reinforcement structure 195 and the second reinforcement structure 196 into additional separation regions, which in this embodiment are configured as a first reinforcement post 231, a second reinforcement post 232, a third reinforcement post 233, a fourth reinforcement post 234, a fifth reinforcement post 235, and a sixth reinforcement post 236.

[0021] In the first embodiment of the method presented, a plasma etching method, particularly the DRIE etching method, is used as the etching method in method step 80.

[0022] In the first embodiment of the method presented, in method step 10, a silicon wafer 100 having a thickness 119 of substantially 300 to 400 μm is provided.

[0023] In a further method step 60, in the first embodiment of the method, a first metal layer 170 is applied to the outer surface 151 of the silicon layer 150. In this case, the first metal layer is configured as a gold layer, and the gold layer is applied to a region of the silicon layer 150, which then corresponds to a first separation region 200 of the silicon layer 150. Further, a second metal layer 171 is applied to the outer surface 151 of the silicon layer 150. Again, in this case, the second metal layer 171 is configured as a gold layer, and the gold layer is hereby applied to a region of the silicon layer 150, which then corresponds to a second separation region 201 of the silicon layer 150.

[0024] Further, in method step 50 following method step 40, two marks 160 and 161 are applied to the silicon layer 150. These two marks 160 and 161 are etched into the outer surface 151 of the silicon layer 150. These marks 160 and 161 are used to orient the first metal layer 170 relative to a first separation region 131 of the silicon oxide layer 130 and to orient the second metal layer 171 relative to at least a second separation region 132 of the silicon oxide layer. To ensure that the marks 160 and 161 are applied to the silicon layer 150 in the correct position, an infrared measurement device (not shown here) is used to detect the first separation region 131 and the second separation region 132 of the silicon oxide layer 130 buried within a layer stack having a silicon wafer 100 and silicon layers. The two marks 131 and 132 are thus applied specifically to the edge regions of the layer stack.

[0025] Furthermore, the outer surface 152 of the first separation region 200 of the silicon layer 150 and the outer surface 153 of the second separation region 201 of the silicon layer are indirectly connected to the adhesive tape 220. In the presented case, the first metal layer 170 and the second metal layer 171 are directly and material-lockedly connected to the adhesive tape 220. In the presented embodiment, the adhesive tape 220 serves as an etch stop layer during the etching process in method step 80. On the other hand, the adhesive tape 220, particularly configured as a single-sided adhesive tape, is used to transport the manufactured first and second micromirror devices to the corresponding drive units (especially piezoelectric drive units) of the micromirrors, which are not shown here.

[0026] In a further method step 90, the etch mask 180, which is configured as a hard mask, is removed by means of an oxide etching process. Here, the exposed areas 241 of the first separation region 131 and the exposed areas 242 of the second separation region 132 of the silicon oxide layer 130 are also etched away.

[0027] exist Figures 1b.1 to 1b.4 The diagram schematically illustrates the method steps of a second embodiment of a method for manufacturing at least one first and second micromirror device. Unlike the first embodiment, in method step 11, a silicon wafer 101 having a thickness 126 of substantially 725 μm is provided. Furthermore, in the subsequent method step 20, a silicon oxide layer 130 is applied not only to the front side 110 of the silicon wafer 101 but also additionally to the back side 120 of the silicon wafer 101. Further, unlike the first embodiment of the method, in method step 65 following method step 60, the back side 120 of the silicon wafer 101 is ground away until a target thickness 145 of the silicon wafer 101 is reached. The target thickness 145 here corresponds to a thickness of the silicon wafer 101 substantially between 300 μm and 400 μm.

[0028] Figure 2A first micromirror device 300 is shown, which is particularly aided by means of... Figures 1a.1 to 1a.3 or Figures 1b.1 to 1b.4 The method described herein is used for fabrication. Here, the micromirror device 300 has a reinforcement structure 310, which is divided into a first reinforcement pillar 311, a second reinforcement pillar 312, and a third reinforcement pillar 313. Each reinforcement pillar 311, 312, and 313 has a portion of a first separation region 325 of the silicon wafer and a portion of a first separation region 330 of the silicon oxide layer. The reinforcement pillars 311, 312, and 313 can also be connected to each other by lateral pillars not shown herein. Further, the first micromirror device 300 has a first mirror plate 320. This mirror plate 320 has a first separation region 345 of a silicon layer 350. The silicon layer 350 is configured as a polycrystalline silicon layer. In the presented case, the polycrystalline silicon layer has a layer thickness 360 of substantially 20 μm.

Claims

1. A method for manufacturing at least one first micromirror device (205, 300) and a second micromirror device (206), wherein, The method comprises the following steps: - Provides a silicon wafer (100, 101) having a front side (110) and a back side (120), and - A silicon oxide layer (130) is applied to at least the front side (110) of the silicon wafer (100, 101), and - Remove the silicon oxide layer (130) to create at least one first separation region (131) and at least one second separation region (132) of the silicon oxide layer (130), wherein the first separation region (131) and the second separation region (132) of the silicon oxide layer (130) are spatially separated from each other along a separation plane (140), and - Apply silicon layers (150, 350) to the front side (110) of the silicon wafer (100, 101) and the first separation region (131) and the second separation region (132) of the silicon oxide layer (130), and An etching mask (180) is applied to the back side (120) of the silicon wafer (100), wherein the etching mask (180) has a first opening (190) along the separation plane (140) of the first separation region (131) and the second separation region (132) of the silicon oxide layer (130), and -Based on the etching mask (180) on the back side (120) of the silicon wafer (100, 101) and the first separation region (131) and the second separation region (132) of the silicon oxide layer (130) of the silicon wafer (100, 101), the silicon layer (150, 350) and the silicon wafer (100, 101) are removed by etching, thereby producing at least one first micromirror device (205, 300) and a second micromirror device (206). The etching mask (180) further includes at least one additional opening for separating the reinforcement structure of the first micromirror device (205, 300) into a first separation region and a second separation region of the reinforcement structure, wherein the reinforcement structure includes at least two reinforcement struts extending parallel to each other.

2. The method according to claim 1, characterized in that, By removing the silicon layers (150, 350) using the etching method, at least one first separation region (200, 345) and a second separation region (201) of the silicon layers (150, 350) are generated, wherein the first separation region (200) and the second separation region (201) of the silicon layers (150, 350) are arranged spatially separated from each other along the separation plane (140), thereby generating a first mirror plate (211, 320) of the first micromirror device (205, 300) and a second mirror plate (212) of the second micromirror device (206), the first mirror plate having the first separation region (200, 345) of the silicon layers (150, 350) and the second mirror plate having the second separation region (201) of the silicon layers (150, 350).

3. The method according to any one of claims 1 or 2, characterized in that, By removing the silicon wafer (100, 101) using the etching method, at least one first separation region and a second separation region of the silicon wafer (100, 101) are generated, wherein the first separation region and the second separation region of the silicon wafer (100, 101) are arranged spatially separated from each other along the separation plane, thereby generating a first reinforcement structure (195, 310) of the first micromirror device (205, 300) and a second reinforcement structure (196) of the second micromirror device (206), wherein the first reinforcement structure has the first separation region of the silicon wafer (100, 101) and a first separation region (131) of the silicon oxide layer (130), and the second reinforcement structure has the second separation region of the silicon wafer (100, 101) and a second separation region of the silicon oxide layer (100, 101).

4. The method according to claim 3, characterized in that, The etching mask (180) has at least one second opening (221) for separating the first reinforcement structure (195, 310) into a first reinforcement post (231, 311) and a second reinforcement post (232, 312) of the first reinforcement structure (195, 310).

5. The method according to claim 1 or 2, characterized in that, Plasma etching was used as the etching method.

6. The method according to claim 1 or 2, characterized in that, A silicon wafer (100) with a thickness (119) of substantially 300 to 400 μm is provided.

7. The method according to claim 1 or 2, characterized in that, A silicon wafer (101) with a thickness (126) of approximately 725 μm is provided.

8. The method according to claim 7, characterized in that, In a further method step, after applying silicon layers (150, 350) to the front side (110) of the silicon wafer (100, 101) and to the silicon oxide layer (130), the back side (120) of the silicon wafer (100, 101) is ground away.

9. The method according to claim 1 or 2, characterized in that, The silicon oxide layer (130) is additionally applied to the back side (120) of the silicon wafer (100, 101).

10. The method according to claim 1 or 2, characterized in that, In a further method step, a first metal layer (170) is applied to the silicon layer (150, 350), and a second metal layer (171) is applied to the silicon layer (150, 350).

11. The method according to claim 10, characterized in that, In order to orient the first metal layer (170) relative to a first separation region (131) of the silicon oxide layer (130) and in order to orient the second metal layer (171) relative to at least a second separation region (132) of the silicon oxide layer (130), at least two markings (160, 161) are applied on the silicon layer (150, 350).

12. The method according to claim 1 or 2, characterized in that, The silicon layer (150, 350) is directly or indirectly connected to the adhesive tape (220).

13. The method according to claim 1 or 2, characterized in that, In a further method step, the etch mask (180) is removed.

14. The method according to claim 1 or 2, characterized in that, The silicon layers (150, 350) are applied as silicon deposits to the front side (110) of the silicon wafer (100, 101) and to the first separation region (131) and the second separation region (132) of the silicon oxide layer (130), and the deposited silicon is polished.

15. The method according to claim 1, characterized in that, The silicon wafers (100, 101) are plate-shaped; and / or The thickness (135) of the silicon oxide layer (130) is in the range of 1 μm to 3 μm; and / or The silicon oxide layer (130) is removed down to the outer surface (111) of the silicon wafer (100, 101); and / or The silicon layer (150, 350) is a polycrystalline silicon layer having a layer thickness (116) in the range of 5 μm to 50 μm.

16. The method according to claim 5, characterized in that, The plasma etching method is the DRIE etching method.

17. The method according to claim 8, characterized in that, The back side (120) of the silicon wafer (100, 101) is ground away until the target thickness (145) of the silicon wafer (100, 101) is reached.

18. The method according to claim 10, characterized in that, The first metal layer (170) is a first gold layer or a first aluminum layer; and / or The second metal layer (171) is a second gold layer or a second aluminum layer; and / or The first metal layer (170) is applied to the outer surface (152) of the first separation region (200, 345) of the silicon layer (150, 350); and / or The second metal layer (171) is applied to the outer surface (153) of the second separation region (201) of the silicon layer (150, 350).

19. The method according to claim 12, characterized in that, The outer surface (152) of the first separation region (200, 345) of the silicon layer (150, 350) and the outer surface (153) of the second separation region (201) of the silicon layer (150, 350) are directly or indirectly connected to the adhesive tape (220); and / or The adhesive tape (220) is a single-sided adhesive tape.

20. The method according to claim 14, characterized in that, The silicon in question is polycrystalline silicon.

21. A first micromirror device (205, 300) and / or a second micromirror device (206), wherein the first micromirror device and / or the second micromirror device are manufactured by the method according to any one of the preceding claims.

22. A first micromirror device (205, 300) and / or a second micromirror device (206), the first micromirror device and / or the second micromirror device being manufactured by means of any one of claims 1 to 20, the first micromirror device and / or the second micromirror device having a first mirror plate (211, 320) and / or a second mirror plate (212), the first mirror plate and / or the second mirror plate having a polycrystalline silicon layer respectively.

23. The first micromirror apparatus (205, 300) and / or the second micromirror apparatus (206) according to claim 22, characterized in that, The thickness (360) of the polycrystalline silicon layer is in the range of 5 μm to 50 μm.

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