MEMS chip and microphone
By setting a sacrificial structure on the conductive layer of the MEMS chip, and corroding these structures is preferred during the corrosion process, the problem of releasing the solution corroding the conductive layer is solved, and the corrosion resistance of the chip and the stability of the electrical connection are improved.
Patent Information
- Application Number
- CN202421642286.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-11
- Publication Date
- 2025-04-25
- Estimated Expiration
- 2034-07-11
AI Technical Summary
During the corrosion of the cavity structure, the release solution of the release process corrodes the conductive layer below along the boundary of the bonding point of the bonding line, causing the conductive layer to break and destroy the electrical connection between the bonding line connection point and the conductive layer.
The sacrificial structure is provided on the conductive layer of the MEMS chip, including metal points, conductive plates and isolation grooves, through which the sacrificial structure is preferred to corrode the sacrificial structure during the corrosion process, protecting the electrodes and conductive layers.
The probability of the electrical connection between the electrode and the conductive layer being destroyed is reduced, and the corrosion resistance of the MEMS chip during the corrosion process is improved.
Smart Images
Figure CN222795169U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of semiconductors, in particular to a MEMS chip and a microphone. Background Art
[0002] The main application examples of MEMS (Micro Electro Mechanical Systems) chips include pressure sensors, accelerometers, and silicon microphones. MEMS chips are generally first deposited with a polysilicon conductive layer, then evaporated or sputtered metal on the conductive layer as a wire connection point, and then the cavity structure is etched out through a release process. However, during the process of etching the cavity structure, the release solution of the release process will corrode the conductive layer below along the boundary of the wire connection point, causing the conductive layer to break and destroying the electrical connection between the wire connection point and the conductive layer. Utility Model Content
[0003] The utility model provides a MEMS chip and a microphone, aiming to effectively solve the technical problem in the prior art that during the corrosion process of the cavity structure, the release solution of the release process will corrode the underlying conductive layer along the boundary of the welding wire connection point, causing the conductive layer to break and destroying the electrical connection between the welding wire connection point and the conductive layer.
[0004] According to a first aspect of the utility model, the utility model provides a plate, comprising: a conductive layer, an electrode and a sacrificial structure; the electrode and the sacrificial structure are arranged on the conductive layer, a protective structure is arranged between the sacrificial structure and the electrode, and the sacrificial structure has conductivity.
[0005] Furthermore, the sacrificial structure is a metal point made of metal, the protective structure is a conductive column, and two ends of the conductive column are fixedly connected to the sacrificial structure and the electrode respectively.
[0006] Furthermore, the shape of the metal dots is the same as that of the electrodes.
[0007] Furthermore, the sacrificial structure is a graphical geometric figure having defects.
[0008] Furthermore, the sacrificial structure is a conductive plate disposed around the conductive layer, and the protective structure is an isolation groove, the isolation groove separates the electrode from the conductive plate, and the isolation groove separates the conductive layer from the conductive plate.
[0009] Furthermore, the surface of the conductive plate is a rough surface.
[0010] Furthermore, the area of the conductive plate is greater than the sum of the areas of the conductive layer and the electrode.
[0011] Furthermore, the width of the isolation groove is greater than or equal to a preset width.
[0012] Furthermore, the rough surface of the conductive plate is formed by etching, and the isolation groove is formed by etching.
[0013] According to a second aspect of the utility model, the utility model further provides a microphone, comprising the above-mentioned MEMS chip.
[0014] Through one or more of the above embodiments of the present invention, at least the following technical effects can be achieved:
[0015] In the technical solution disclosed in the utility model, a sacrificial structure is set on the conductive layer of the back plate. In the process of corroding the cavity structure using a release process, the release solution will first corrode the conductive layer under the sacrificial structure, which reduces the probability of the conductive layer under the electrode being corroded, thereby reducing the probability of the electrical connection between the electrode and the conductive layer being destroyed. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The technical solutions and other beneficial effects of the present invention will be made apparent by describing in detail the specific embodiments of the present invention in conjunction with the accompanying drawings.
[0017] Figure 1 A schematic diagram of the back plate structure of a MEMS chip provided in one embodiment of the utility model;
[0018] Figure 2 A schematic diagram of the back plate structure of a MEMS chip provided by another embodiment of the utility model;
[0019] Figure 3 A schematic diagram of the back plate structure of a MEMS chip provided in yet another embodiment of the utility model. Description of the drawings:
[0021] 10. Conductive layer; 101. Electrode; 102. Sacrificial structure; 103. Protective structure; 104. Metal point; 105. Conductive plate; 106. Conductive column; 107. Isolation groove; 108. Geometric figure; 109. Defect. DETAILED DESCRIPTION
[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.
[0023] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article, unless otherwise specified, generally indicates that the associated objects before and after are in an "or" relationship.
[0024] Figure 1 The figure shows a MEMS chip provided by an embodiment of the utility model, including: a conductive layer 10, an electrode 101 and a sacrificial structure 102; wherein the electrode 101 and the sacrificial structure 102 are arranged on the conductive layer 10, a protective structure 103 is arranged between the sacrificial structure 102 and the electrode 101, and the sacrificial structure 102 is conductive.
[0025] In this embodiment, when using the etching process in the semiconductor process, due to the different potentials of the polysilicon and the electrode 101 of the MEMS chip, the metal with a higher potential of the electrode 101 becomes the cathode, which plays a role in transferring electrons, and the polysilicon with a more negative potential becomes the anode, which continuously loses electrons and becomes ions entering the solution, thereby being corroded, and forming a primary cell corrosion in the released solution. The greater the potential difference of the primary cell, the easier it is to transfer charges, which promotes the interaction between the reactants, thereby accelerating the reaction rate.
[0026] The oxidation reaction of polysilicon as anode and cathode is: Si - 2e - +6HF→SiF6 2- +4H + +H2
[0027] The reduction reaction corresponding to electrode 101 as cathode and anode is: 2H + +2e - =H2
[0028] Galvanic cell corrosion is related to the difference in natural potential of different metal materials in the corrosive solution, as well as the ratio of their relative areas and distances. The greater the potential difference, the larger the cathode area, the smaller the anode polarization, the smaller the loop resistance, and the more serious the anode corrosion, and vice versa.
[0029] Therefore, in this embodiment, since the sacrificial structure is conductive, a sacrificial structure is added and the sacrificial structure can also play a similar role as the electrode 101, so that the sacrificial structure becomes an extension of the cathode, thereby increasing the ratio of the electrode 101 to the polysilicon area and reducing corrosion to the anode, i.e., polysilicon.
[0030] The MEMS chip provided in this embodiment has a sacrificial structure 102 set on the conductive layer 10. During the process of corroding the cavity structure using a release process, the release solution will first corrode the conductive layer 10 under the sacrificial structure 102, which reduces the probability of the conductive layer 10 under the electrode 101 being corroded, thereby reducing the probability of the electrical connection between the electrode 101 and the conductive layer 10 being destroyed. Therefore, it should be noted that the corrosion resistance mentioned above refers to the degree of corrosion resistance of components to the corrosive solution in the semiconductor process.
[0031] See also Figure 1 In one embodiment, the sacrificial structure 102 is a metal dot 104 made of metal, and the protective structure 103 is a conductive column 106. The two ends of the conductive column 106 are fixedly connected to the sacrificial structure 102 and the electrode 101 respectively, wherein the material of the conductive column 106 is the same as that of the conductive layer 10.
[0032] In this embodiment, the sacrificial structure 102 is made into a metal point 104 made of metal. After the conductive column 106 connects the electrode 101 and the metal point 104, when the release process is used, since the area of the metal point 104 is larger than the area of the electrode 101, the charge concentration at the position of the metal point 104 is high and the electric potential is high, and corrosion is preferentially performed along the junction between the metal point 104 and the sacrificial structure 102, thereby protecting the conductive layer under the electrode 101 intact.
[0033] See also Figure 2 In one embodiment, the sacrificial structure 102 is a graphical geometric figure 108, and the geometric figure 108 has a defect 109. In this embodiment, the geometric figure 108 is a regular circle. In other embodiments, the geometric figure 108 can also be a regular rectangle, trapezoid, or irregular shape, etc.
[0034] In this embodiment, the sacrificial structure 102 is a defective polysilicon. In addition to the original corrosion reaction, the defective polysilicon can also increase the reaction speed of the polysilicon in the area and change the local concentration of the corrosion solution. In this way, the concentration of the corrosion solution near the electrode 101 is reduced, which can reduce the corrosion of the polysilicon near the electrode 101.
[0035] In this embodiment, an external geometric figure 108 is connected and a defect 109 is etched. Since the electron concentration at the defect 109 is high, the electrochemical reaction is more likely to occur there, so it will be corroded first during the etching process, thereby protecting the film layer at the electrode 101 from corrosion.
[0036] In one embodiment, when the sacrificial structure 102 is a metal dot 104 , the shape of the metal dot 104 is the same as the shape of the electrode 101 .
[0037] In this embodiment, by making the shape of the metal dot 104 the same as that of the electrode 101 , the transfer of the ions of the etching solution can be made symmetrical, thereby facilitating the etching solution to corrode the conductive layer 10 under the metal dot 104 .
[0038] See also Figure 3 In one embodiment, the sacrificial structure 102 is a conductive plate 105 arranged around the conductive layer 10, and the protective structure 103 is an isolation groove 107, which separates the electrode 101 from the conductive plate 105, and the isolation groove 107 separates the conductive layer 10 from the conductive plate 105.
[0039] In this embodiment, the isolation groove 107 is formed by etching, and the isolation groove 107 is penetrated in its depth direction. The sacrificial structure 102 is made into a conductive plate 105, and the protective structure 103 is made into the isolation groove 107. When using the release process, the conductive plate 105 plays a protective role for the conductive layer 10 and the electrode 101, and the use of the isolation groove 107 can delay the flow of the corrosive liquid to the position of the electrode 101 and the conductive layer 10, thereby reducing the probability of the conductive layer 10 under the electrode 101 being corroded.
[0040] In other embodiments, the isolation groove 107 is not penetrated in the depth direction thereof. When the release process is used, the etching liquid will corrode along the depth direction of the isolation groove 107, thereby disconnecting the conductive plate outside the isolation groove 107. The use of the isolation groove 107 can also delay the etching liquid from flowing to the position of the electrode 101 and the conductive layer 10, thereby reducing the probability of the conductive layer 10 under the electrode 101 being corroded.
[0041] In one embodiment, the surface of the conductive plate 105 is a rough surface, and the rough surface is etched.
[0042] In this embodiment, by setting the surface of the conductive plate 105 to a rough surface, the conductive plate 105 can have a larger surface area, so that the conductive plate 105 can be exposed to more corrosive liquid, thereby accelerating the corrosion rate of the conductive plate 105, thereby further reducing the probability of the conductive layer 10 under the electrode 101 being corroded.
[0043] In one embodiment, the area of the conductive plate 105 is greater than the sum of the areas of the conductive layer 10 and the electrode 101 .
[0044] In this embodiment, the conductive plate 105 arranged in this way can make the area of the conductive plate 105 larger, thereby further delaying the flow of the corrosive liquid to the electrode 101 and the conductive layer 10, and reducing the probability of the conductive layer 10 under the electrode 101 being corroded.
[0045] In one embodiment, the width of the isolation trench 107 is greater than or equal to a preset width.
[0046] In this embodiment, the preset width can be any value in the range of 1-5 μm. For example, the preset width can be 1 μm, and the width of the isolation groove 107 is greater than or equal to 1 μm. The isolation groove 107 set in this way has a certain width, which can fully delay the flow of the etching solution to the position of the electrode 101 and the conductive layer 10, thereby reducing the probability of the conductive layer 10 under the electrode 101 being corroded. It should be noted that the above 1 μm is only a distance description of this embodiment, and any value in the range of 1-5 μm, such as 2 μm, 3 μm, 4 μm, 5 μm, etc., as long as it is in the range of 1-5 μm, is within the protection scope of this application.
[0047] In one embodiment, the present application further provides a microphone, comprising the MEMS chip described in the above embodiment.
[0048] In summary, although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.
Claims
1. A MEMS chip, comprising a back plate, characterized in that: The back plate comprises: a conductive layer (10), an electrode (101) and a sacrificial structure (102); The electrode (101) and the sacrificial structure (102) are arranged on the conductive layer (10), a protective structure (103) is arranged between the sacrificial structure (102) and the electrode (101), and the sacrificial structure (102) is conductive.
2. The MEMS chip according to claim 1, characterized in that: The sacrificial structure (102) is a metal point (104) made of metal, the protective structure (103) is a conductive column (106), and two ends of the conductive column (106) are fixedly connected to the sacrificial structure (102) and the electrode (101) respectively.
3. The MEMS chip according to claim 2, characterized in that: The shape of the metal dot (104) is the same as that of the electrode (101).
4. The MEMS chip according to claim 1, characterized in that: The sacrificial structure (102) is a patterned geometric figure (108), and the geometric figure (108) has defects (109).
5. The MEMS chip according to claim 1, characterized in that: The sacrificial structure (102) is a conductive plate (105) arranged around the conductive layer (10), and the protective structure (103) is an isolation groove (107), wherein the isolation groove (107) separates the electrode (101) and the conductive plate (105), and the isolation groove (107) separates the conductive layer (10) and the conductive plate (105).
6. The MEMS chip according to claim 5, characterized in that: The surface of the conductive plate (105) is a rough surface.
7. The MEMS chip according to claim 5, characterized in that: The area of the conductive plate (105) is greater than the sum of the areas of the conductive layer (10) and the electrode (101).
8. The MEMS chip according to claim 5, characterized in that: The width of the isolation groove (107) is greater than or equal to a preset width.
9. The MEMS chip according to claim 6, characterized in that: The rough surface of the conductive plate is formed by etching, and the isolation groove is formed by etching.
10. A microphone, characterized in that: Comprising the MEMS chip as described in any one of claims 1-9.