Diaphragm deflection angle feedback device, micro-mirror with same and packaging process

Abstract

The present application provides a micromirror, comprising a substrate, the micromirror is fixedly connected with the substrate; a capacitance detection mechanism, the capacitance detection mechanism comprises: a detection electrode, the detection electrode is located on the substrate; a shielding electrode, the shielding electrode is located on the substrate, and the shielding electrode is sleeved outside the detection electrode; wherein the detection electrode and the shielding electrode are electrically connected with the substrate. A packaging process, comprising: cutting and removing the micromirror from a wafer; a substrate is arranged and fixed by a bonding metal layer on the back of the micromirror; a detection electrode is formed on the substrate and located in the back cavity of the micromirror; a shielding electrode is formed on the substrate and located in the back cavity of the micromirror. The present application can infer the distance between the diaphragm and the detection electrode by detecting the capacitance between the diaphragm and the detection electrode, so as to feed back the deflection state of the diaphragm, while shielding the stray signals generated in the capacitance detection process, and improving the detection accuracy.

Description

Technical Field

[0001] This specification relates to the field of micromirror detection technology, and more particularly to a diaphragm deflection angle feedback device, a micromirror having the same, and a packaging process thereof. Background Technology

[0002] Currently, micromirrors are a type of micro / nano chip that can effectively control optical paths and are widely used in projection, imaging, laser navigation, and other fields. The most commonly used micromirrors include electrostatic, electromagnetic, piezoelectric, and electrothermal types. Most currently used micromirrors employ capacitive sensing for angle feedback. However, a drawback is that the sensing electrodes generate a large amount of stray signals during the sensing process, affecting the accuracy of the capacitive sensing and leading to delayed feedback.

[0003] In summary, this application proposes a diaphragm deflection angle feedback device, a micromirror having the same, and a packaging process to solve the aforementioned problems. Summary of the Invention

[0004] The present invention aims to solve the problems mentioned in the background art. The purpose of one or more embodiments of this specification is to provide a diaphragm deflection angle feedback device, a micromirror having the same, and a packaging process, to eliminate stray signals, improve detection accuracy, and provide favorable conditions for subsequent compensation.

[0005] To achieve the above objectives, one or more embodiments of this specification provide a diaphragm deflection angle feedback device based on capacitance detection, comprising: a substrate; a capacitance detection mechanism, the capacitance detection mechanism comprising: a detection electrode located on the substrate; and a shielding electrode located on the substrate and sleeved outside the detection electrode; wherein the detection electrode and the shielding electrode are both electrically connected to the substrate.

[0006] According to an embodiment of the present invention, a diaphragm deflection angle feedback device based on capacitance detection forms a capacitor between the detection electrode and the diaphragm. According to the capacitance formula, the capacitance C = ε·A / d (where ε is the dielectric constant, A is the area of ​​the capacitor, and d is the distance between the detection electrode and the diaphragm). When the diaphragm vibrates and undergoes angular deflection, the distance between the diaphragm and the detection electrode can be estimated by detecting the capacitance between them, thereby estimating the deflection angle of the diaphragm and providing feedback on the diaphragm's deflection state. Surrounding the detection electrode with a shielding electrode eliminates stray signals during the capacitance detection process, improving detection accuracy.

[0007] According to an embodiment of the present invention, the diaphragm deflection angle feedback device based on capacitance detection further includes: a first support member and a second support member, both the first support member and the second support member being disposed on a substrate, the detection electrode being disposed at the end of the second support member away from the substrate, and the shielding electrode being disposed at the end of the first support member away from the substrate.

[0008] According to the embodiment of the present invention, the diaphragm deflection angle feedback device based on capacitance detection has the first support member and the second support member having the same height.

[0009] According to the diaphragm deflection angle feedback device based on capacitance detection according to an embodiment of the present invention, the first support member or the second support member is a low-resistivity silicon pillar.

[0010] According to an embodiment of the present invention, the diaphragm deflection angle feedback device based on capacitance detection further includes: a metal frame, which is sleeved on the outer wall of the substrate and electrically connected to the substrate; and a metal shielding shell, which has a front and a back facing each other, with a receiving cavity formed on the back facing, and the back facing of the metal shielding shell is fixedly connected to the metal frame.

[0011] According to an embodiment of the present invention, a micromirror is provided with the diaphragm deflection angle feedback device based on capacitance detection described above. The micromirror has a front side and a back side, the back side having a back cavity. The back side of the micromirror is bonded to a substrate, and the detection electrode and the shielding electrode are both located inside the back cavity.

[0012] According to an embodiment of the present invention, a micromirror has an isolation layer disposed between its back surface and a substrate.

[0013] According to an embodiment of the present invention, a packaging process is used to form the aforementioned micromirror. The packaging process includes: cutting and removing the micromirror from a wafer, the micromirror having a front side and a back side, the back side having a back cavity; providing a substrate bonded to the back side of the micromirror by a bonding metal layer, the substrate having a first pad and a second pad, and providing an isolation layer that isolates the back side of the micromirror from the wiring area of ​​the first pad and the second pad on the substrate; forming a detection electrode on the substrate and located in the back cavity of the micromirror, the detection electrode being electrically connected to the second pad; and forming a shielding electrode on the substrate and located in the back cavity of the micromirror, the shielding electrode being sleeved outside the detection electrode and electrically connected to the first pad.

[0014] According to an embodiment of the present invention, a packaging process includes fixing a first support and a second support on the substrate and in the back cavity of the micromirror, wherein a detection electrode is located on the second support and a shielding electrode is located on the first support.

[0015] According to an embodiment of the present invention, a packaging process further includes: cutting and removing a micromirror from a wafer, the micromirror having a front side and a back side, the back side having a back cavity; providing a substrate bonded and fixed to the back side of the micromirror, the substrate having a first pad and a second pad; bonding a first support member made of low-resistivity silicon material, electrically connected to the first pad and a second support member electrically connected to the second pad, to the substrate and located inside the back cavity of the micromirror; bonding a detection electrode to the second support member; and bonding a shielding electrode to the first support member.

[0016] According to an embodiment of the present invention, the packaging process further includes: forming a third pad on the substrate; providing a metal frame fixedly connected to the sidewall of the substrate, the metal frame being electrically connected to the third pad; bonding a metal shielding shell to the side of the metal frame near the micromirror, the metal shielding shell having a receiving cavity on the side near the substrate, the micromirror being located inside the receiving cavity.

[0017] The beneficial effects of the present invention will be described in detail below with reference to embodiments and accompanying drawings. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in one or more embodiments of this specification or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one or more embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the external structure of the micromirror and the substrate in an embodiment of the present invention;

[0020] Figure 2 This is an exploded view of the structure of the micromirror, detection electrode, shielding electrode, and substrate in an embodiment of the present invention;

[0021] Figures 3-4 This is an exploded view of the structure of the micromirror, detection electrode, shielding electrode, low-resistivity silicon, and substrate in an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of the substrate structure in an embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of the structure of the metal shielding shell and the metal frame in an embodiment of the present invention;

[0024] Figure 7 This is an exploded view of the structure of the metal shielding shell, metal frame, micromirror, capacitance detection mechanism and substrate in an embodiment of the present invention;

[0025] Figure 8 This is a cross-sectional view of the metal shielding shell, metal frame, micromirror, capacitance detection mechanism, and substrate in an embodiment of the present invention.

[0026] In the attached figures: 1. Metal shielding shell; 2. Metal frame; 3. Micromirror; 4. Capacitance detection mechanism; 41. Detection electrode; 42. Shielding electrode; 43. First support member; 44. Second support member; 45. First bonding layer; 46. Second bonding layer; 47. First pad; 48. Second pad; 5. Substrate; 51. Third pad; 6. Bonding metal layer; 7. Isolation layer. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments.

[0028] The following is based on Figures 1-8 The specific structure of the micromirror in the embodiments of the present invention will be described.

[0029] Example 1

[0030] Please see Figures 1-8 According to an embodiment of the present invention, the micromirror 3 has a front side and a back side, and the back side has a back cavity.

[0031] The micromirror 3 includes a diaphragm deflection angle feedback device based on capacitance detection. This device comprises a substrate 5 and a capacitance detection mechanism 4. The capacitance detection mechanism 4 includes a detection electrode 41 and a shielding electrode 42. The back surface of the micromirror 3 is bonded and fixed to the substrate 5. Optionally, an isolation layer 7 is provided between the wiring area on the substrate 5 and the back surface of the micromirror 3. The detection electrode 41 is disposed on the substrate 5 and corresponds to the position of the diaphragm of the micromirror 3. The shielding electrode 42 is disposed on the substrate 5 and is sleeved outside the detection electrode 41. Both the detection electrode 41 and the shielding electrode 42 are electrically connected to the substrate 5. A capacitance is formed between the detection electrode 41 and the diaphragm of the micromirror 3. When the diaphragm of the micromirror 3 vibrates and causes an angular deflection, the capacitance between the diaphragm and the detection electrode 41 is detected by the capacitance detection circuit (capacitance detection by the capacitance detection circuit is existing technology). The capacitance is obtained by the capacitance formula C=ε·A / d (where ε is the dielectric constant, A is the area of ​​the capacitor, and d is the distance between the detection electrode 41 and the diaphragm). The distance between the diaphragm and the detection electrode 41 can then be estimated, thereby estimating the deflection angle of the diaphragm and determining the working state of the diaphragm. The shielding electrode 42 surrounds the detection electrode 41 to eliminate stray signals around the detection electrode 41, making the detection result of the detection electrode 41 more accurate.

[0032] The capacitance detection mechanism 4 according to an embodiment of the present invention further includes a first support member 43 and a second support member 44. Both the first support member 43 and the second support member 44 are disposed on a substrate 5. A detection electrode 41 is disposed at the end of the second support member 44 away from the substrate 5, and a shielding electrode 42 is disposed at the end of the first support member 43 away from the substrate 5. The second support member 44 shortens the distance between the detection electrode 41 and the diaphragm, enhancing the capacitance signal. Optionally, the first support member 43 and the second support member 44 are low-resistivity silicon pillars. Both the first support member 43 and the second support member 44 are bonded to the substrate 5. The detection electrode 41 is bonded to the second support member 44, and the shielding electrode 42 is bonded to the first support member 43. Both the detection electrode 41 and the shielding electrode 42 are electrically connected to the substrate 5 through the low-resistivity silicon pillars. The shielding electrode 42 and the detection electrode 41 do not need to be separately wired to the substrate 5, and the distance between the detection electrode 41 and the diaphragm of the micromirror 3 can be shortened. Optionally, the first support member 43 and the second support member 44 have the same height, which facilitates better shielding of stray signals around the detection electrode 41 by the shielding electrode 42.

[0033] According to an embodiment of the present invention, the capacitance detection mechanism 4 further includes a metal frame 2 and a metal shielding shell 1. The metal frame 2 is sleeved on the outer wall of the substrate 5 and is electrically connected to the substrate 5. The metal shielding shell 1 has a front and a back facing each other. A receiving cavity is opened on the back. The back of the metal shielding shell 1 is fixedly connected to the metal frame 2. The metal shielding shell 1 and the metal frame 2 form an outer shielding layer, which further eliminates stray signals in the capacitance detection process and improves the detection accuracy.

[0034] Example 2

[0035] The packaging process according to an embodiment of the present invention includes the following steps:

[0036] S1, Micromirror 3 is cut off from the wafer. Micromirror 3 has a front side and a back side with opposite sides. The back side has a back cavity.

[0037] S2, a substrate 5 is provided and bonded to the back of the micromirror 3 via a bonding metal layer 6. The substrate 5 has a first pad 47 and a second pad 48. Optionally, an isolation layer 7 is provided on the trace area of ​​the first pad 47 and the second pad 48 on the substrate 5 to isolate it from the back of the micromirror 3.

[0038] S3, a detection electrode 41 is formed on the substrate 5 and in the back cavity of the micromirror 3, and the detection electrode 41 is electrically connected to the second pad 48.

[0039] S4, a shielding electrode 42 is formed on the substrate 5, located in the back cavity of the micromirror 3. The shielding electrode 42 is sleeved outside the detection electrode 41 and is electrically connected to the first pad 47. Optionally, a first support member 43 and a second support member 44 are fixed on the substrate 5, located in the back cavity of the micromirror 3. The detection electrode 41 is located on the second support member 44, and the shielding electrode 42 is located on the first support member 43. Optionally, the first support member 43 and the second support member 44 are provided with the same height.

[0040] S5, a third pad 53 is formed on the substrate 5; a metal frame 2 is fixedly connected to the side wall of the substrate 5, and the metal frame 2 is electrically connected to the third pad 53; a metal shielding shell 1 is bonded to the side of the metal frame 2 near the micromirror 3, and a receiving cavity is opened on the side of the metal shielding shell 1 near the substrate 5, and the micromirror 3 is located inside the receiving cavity.

[0041] Example 3

[0042] The packaging process according to an embodiment of the present invention includes the following steps:

[0043] S1, Micromirror 3 is cut off from the wafer. Micromirror 3 has a front side and a back side with opposite sides. The back side has a back cavity.

[0044] S2, a substrate 5 is provided and bonded to the back of the micromirror 3. The substrate 5 has a first pad 47 and a second pad 48.

[0045] S3, on the substrate 5 and inside the back cavity of the micromirror 3, a first support 43 made of low-resistivity silicon material is bonded to a first support 43 electrically connected to a first pad 47 via a first bonding layer 45 and a second support 44 electrically connected to a second pad 48 via a second bonding layer 46.

[0046] S4, the detection electrode 41 is bonded to the second support 44.

[0047] S5, the shielding electrode 42 is bonded to the first support 43.

[0048] S6, a third pad 53 is formed on the substrate 5; a metal frame 2 is fixedly connected to the side wall of the substrate 5, and the metal frame 2 is electrically connected to the third pad 53; a metal shielding shell 1 is bonded to the side of the metal frame 2 near the micromirror 3, and a receiving cavity is opened on the side of the metal shielding shell 1 near the substrate 5, and the micromirror 3 is located inside the receiving cavity.

[0049] One or more embodiments of this specification are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this specification should be included within the scope of protection of this disclosure.

Claims

1. A diaphragm deflection angle feedback device based on capacitance detection, characterized in that, include: base(5); A capacitance detection mechanism (4) comprising: A detection electrode (41) is located on a substrate (5); A shielding electrode (42) is located on a substrate (5) and is sleeved outside the detection electrode (41); The detection electrode (41) and the shielding electrode (42) are both electrically connected to the substrate (5); The capacitance detection mechanism (4) also includes: The first support member (43) and the second support member (44) are both disposed on the substrate (5). The detection electrode (41) is disposed at the end of the second support member (44) away from the substrate (5). The shielding electrode (42) is disposed at the end of the first support member (43) away from the substrate (5).

2. The diaphragm deflection angle feedback device based on capacitance detection according to claim 1, characterized in that, The first support member (43) and the second support member (44) have the same height.

3. The diaphragm deflection angle feedback device based on capacitance detection according to claim 1 or 2, characterized in that, The first support member (43) or the second support member (44) are both low-resistivity silicon pillars.

4. The diaphragm deflection angle feedback device based on capacitance detection according to claim 1, characterized in that, The capacitance detection mechanism (4) also includes: A metal frame (2) is sleeved on the outer side wall of the substrate (5) and is electrically connected to the substrate (5); A metal shielding shell (1) has a front and a back side, the back side of which has a receiving cavity, and the back side of the metal shielding shell (1) is fixedly connected to a metal frame (2).

5. A micromirror, incorporating a diaphragm deflection angle feedback device based on capacitance detection as described in any one of claims 1-4, characterized in that, The micromirror (3) has a front and a back side, the back side has a back cavity, the back side of the micromirror (3) is bonded to the substrate (5), and the detection electrode (41) and the shielding electrode (42) are both located inside the back cavity.

6. The micromirror according to claim 5, characterized in that, An isolation layer (7) is provided between the back side of the micromirror (3) and the substrate (5).

7. A packaging process for forming the micromirror (3) according to any one of claims 5-6, characterized in that, The packaging process includes: Micromirrors (3) are cut off from the wafer. The micromirrors (3) have opposing front and back sides, and the back side has a back cavity. A substrate (5) is provided and bonded to the back of the micromirror (3) by a bonding metal layer (6). The substrate (5) has a first pad (47) and a second pad (48). An isolation layer (7) is provided on the wiring area of ​​the first pad (47) and the second pad (48) on the substrate (5) to isolate it from the back of the micromirror (3). A detection electrode (41) is formed on the substrate (5) and in the back cavity of the micromirror (3), and the detection electrode (41) is electrically connected to the second pad (48); A shielding electrode (42) is formed on the substrate (5) and in the back cavity of the micromirror (3). The shielding electrode (42) is sleeved outside the detection electrode (41) and is electrically connected to the first pad (47). The packaging process also includes: A first support member (43) and a second support member (44) are fixed on the substrate (5) and in the back cavity of the micromirror (3). The detection electrode (41) is located on the second support member (44) and the shielding electrode (42) is located on the first support member (43).

8. The packaging process according to claim 7, characterized in that, The packaging process includes: Micromirrors (3) are cut off from the wafer. The micromirrors (3) have opposing front and back sides, and the back side has a back cavity. A substrate (5) is provided and bonded to the back side of the micromirror (3), and the substrate (5) has a first pad (47) and a second pad (48). On the substrate (5) and inside the back cavity of the micromirror (3), a first support (43) made of low-resistivity silicon material is bonded to the first pad (47) and a second support (44) electrically connected to the second pad (48). The detection electrode (41) is bonded to the second support (44); A shielding electrode (42) is bonded to the first support (43).

9. The packaging process according to claim 7, characterized in that, The packaging process also includes: A third pad (53) is formed on the substrate (5); A metal frame (2) is fixedly connected to the side wall of the substrate (5), and the metal frame (2) is electrically connected to the third pad (53); A metal shielding shell (1) is bonded to one side of the metal frame (2) near the micromirror (3). The metal shielding shell (1) has a receiving cavity on one side near the substrate (5), and the micromirror (3) is located inside the receiving cavity.

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