Method for manufacturing MEMS device and MEMS device

Abstract

The present application provides a method for manufacturing a MEMS device and a MEMS device. A method for manufacturing a MEMS device includes depositing a thin film on at least a portion of a surface of a sacrificial layer, processing a through-hole in the thin film, removing at least a portion of the material of the sacrificial layer covered by the thin film, discharging the removed material of the sacrificial layer through the through-hole to form a chamber in the sacrificial layer, and depositing a sealing layer on a surface of the thin film remote from the sacrificial layer to seal the through-hole. Compared with the manufacturing method in the prior art, the manufacturing method of the present application needs to deposit only one thin film, shortens the production cycle, and has reliable on-site sealing ability.

Description

Technical Field

[0001] This application relates to the field of encapsulation technology, and particularly to a method for manufacturing a MEMS device and a MEMS device.

Background Art

[0002] In the prior art, the method for encapsulating the chamber inside the device is to deposit a thin film layer on the top of the chamber. The thin film layer has exhaust holes formed by using an etching process. After discharging the gas from the chamber inside the device, the exhaust holes are further sealed with the thin film to realize the encapsulation of the small chamber. However, this method requires specific silicon-based materials / tools, and the process cycle time is long. Some actual applications realize encapsulation by wafer bonding and thin film packaging, but the manufacturing cost and maintenance work increase significantly, and there are process / material limitations in the front end of the line (FEOL) based on complementary metal oxide semiconductor (CMOS).

Summary of the Invention

Problems to be Solved by the Invention

[0003] This application provides a method for manufacturing a MEMS device and a MEMS device that can reduce the manufacturing cycle.

Means for Solving the Problems

[0004] The first aspect of this application provides a method for manufacturing a MEMS device. The manufacturing method includes depositing a thin film on at least a part of the surface of the sacrificial layer, processing through holes in the thin film, removing at least a part of the material covered by the thin film in the sacrificial layer, and discharging the removed material in the sacrificial layer from the through holes to form a chamber in the sacrificial layer, depositing a sealing layer on the surface of the thin film away from the sacrificial layer, and sealing the through holes.

[0005] Compared with the manufacturing method in the prior art, the manufacturing method of the present application only needs to deposit a single layer of thin film, which can shorten the production cycle and have reliable on-site sealing ability.

[0006] In a possible design, before completing the processing of the through holes in the thin film, a structural layer is deposited on at least a part of the surface of the sacrificial layer. The structural layer has a relief part, and at least a part of the material of the thin film is exposed through the relief part.

[0007] In a possible design, after depositing a structural layer on at least a part of the surface of the sacrificial layer, at least a part of the material covering the thin film in the structural layer is removed to form a relief part.

[0008] In a possible design, the material of the thin film is one of a silicon-based material, a polymer, or a metal.

[0009] In a possible design, through holes are processed in the thin film by laser drilling or surface ablation.

[0010] In a possible design, the manufacturing method of the MEMS device is completed in a vacuum environment.

[0011] The second aspect of the present application provides a MEMS device, which is manufactured by the method described above and has the above effects. The MEMS device includes a sacrificial layer, a thin film, a structural layer, and a sealing layer. The sacrificial layer has a chamber. The thin film is provided on the side where the chamber of the sacrificial layer is provided and covers the chamber. The thin film has through holes, and the through holes communicate with the chamber. The structural layer is provided on the side where the chamber of the sacrificial layer is provided. The sealing layer includes a first sealing portion, and the first sealing portion is provided on the side of the thin film away from the sacrificial layer, and the first sealing portion closes the through holes.

[0012] In a possible design, the structural layer is provided with a relief part. The relief part is adjacent to the side of the thin film away from the sacrificial layer, and the first sealing portion is filled in at least a part of the space of the relief part.

[0013] In a possible design, the sealing layer further includes a second sealing portion, the second sealing portion is provided on a side away from the sacrificial layer of the structural layer, the first sealing portion and the second sealing portion are connected by a connecting portion, and the connecting portion and the first sealing portion surround to form a recess.

[0014] In a possible design, the thickness of the structural layer is greater than the thickness of the thin film.

Brief Description of the Drawings

[0015]

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[0016] The drawings here are incorporated into the specification and form a part of the specification, showing embodiments conforming to the present application, and are used to explain the principles of the present application together with the specification.

Modes for Carrying Out the Invention

[0017] To better understand the technical solution of this application, the following will describe the embodiments of this application in detail with reference to the accompanying drawings.

[0018] It is obvious that the described embodiments are only part of the embodiments of this application and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative work are included in the protection scope of this application.

[0019] The terms used in the embodiments of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms "a kind" and "the" used in the embodiments of this application and the appended patent claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0020] It should be understood that the term "and / or" used in this specification only describes the relationship of related objects, and there may be three types of relationships. For example, A and / or B can represent the following relationships, and there are three situations where A exists alone, A and B exist simultaneously, and B exists alone. Here, the symbol " / " generally means that the related objects before and after are in an "or" relationship.

[0021] It should be noted that the terms indicating directions such as "upper", "lower", "left", and "right" described in the embodiments of this application are described from the angles shown in the drawings and should not be construed as limiting the embodiments of this application. Further, in this context, when an element is described as being "connected above" or "connected below" to another element, it should be understood that it can not only be directly connected "above" or "below" to another element, but also be indirectly connected "above" or "below" to another element through an intermediate element.

[0022] A Micro-Electro-Mechanical System (MEMS) refers to high-tech devices with sizes ranging from a few millimeters to smaller, and their internal structures are generally on the micron or nanometer scale. In MEMS devices, there are floating structures, and generally, a sacrificial layer removal process is used to manufacture the floating structures.

[0023] As shown in FIG. 1, a MEMS device is manufactured using the prior art method. First, a part of the material in the sacrificial layer 10 is removed using an etching process to form a chamber 101 in the sacrificial layer 10. A thin film 20 is deposited on the top of the chamber 101. Here, a through-hole 201 is formed by removing a part of the material of the thin film 20 using an etching process. Then, the gas in the chamber 101 is discharged from the through-hole 201, and the through-hole 201 is further sealed using a sealing layer 40 to complete the sealing of the chamber 101. Here, a structural layer 30 is further deposited on the side of the sacrificial layer 10 where the chamber 101 is provided. The thin film 20 is drilled in the structural layer 30, and the thickness of the structural layer 30 is the same as the thickness of the thin film 20. After sealing the through-hole 201, the MEMS device is processed using Chemical Mechanical Polishing (CMP). The applicant found through research that after evacuating the chamber 101 using the manufacturing method in the prior art, on-site sealing cannot be achieved, and the production cycle time is long. In addition, the manufacturing method in the prior art requires a planarization treatment (Chemical Mechanical Polishing, CMP), which is likely to cause problems of structural defects (such as holes, cracks, or delamination). Moreover, the manufacturing method in the prior art is limited to manufacturing the thin film layer 20 using silicon-based materials. Since the thermal expansion coefficients of other materials are different, structural defects (such as cracks and delamination) are likely to exist in the thin film layer 20.

[0024] To solve at least one of the above problems, the present application provides a method for manufacturing a MEMS device, with reference to the flowchart shown in FIG. 2 and the structural changes in the processing process of the MEMS device shown in FIGS. 3 to 6. The method includes the following steps.

[0025] Step S1: Deposit a thin film 2 on at least a part of the surface of the sacrificial layer 1.

[0026] Step S3: Process a through-hole 21 in the thin film 2.

[0027] Step S4: Remove at least a part of the material covered by the thin film 2 in the sacrificial layer 1, and discharge the removed material in the sacrificial layer 1 from the through-hole 21, thereby forming a chamber 11 in the sacrificial layer 1.

[0028] Step S5: Deposit a sealing layer 4 on the surface of the thin film 2 away from the sacrificial layer 1 to seal the through-hole 21.

[0029] In this embodiment, as shown in FIG. 3, first deposit a thin film 2 on the surface of the sacrificial layer 1, and then, as shown in FIG. 4, process a through-hole 21 in the thin film 2. As shown in FIG. 5, remove at least a part of the material covered by the thin film 2 in the sacrificial layer 1, and discharge the removed material in the sacrificial layer 1 from the through-hole 21, thereby forming a chamber 11 in the sacrificial layer 1. As shown in FIG. 6, deposit a sealing layer 4 on the surface of the thin film 2 away from the sacrificial layer 1 to seal the through-hole 21, thereby completing the sealing of the chamber 11. Compared with the manufacturing method in the prior art, the manufacturing method of the embodiment of the present application only needs to deposit one layer of thin film 2, which can shorten the production cycle and has a reliable on-site sealing ability.

[0030] Specifically, as shown in FIG. 2, before step S3 (processing a through-hole 21 in the thin film 2), step S2 is further included.

[0031] In this embodiment, as shown in FIG. 7, the structural layer 3 is deposited on at least a part of the surface of the sacrificial layer 1. Here, as shown in FIG. 8, the structural layer 3 has a embossed portion 31, and at least a part of the material of the thin film 2 is exposed through the embossed portion 31, facilitating the processing of the through hole 21 in the thin film 2 in step S3.

[0032] Here, a plurality of structural layers 3 are deposited on the surface of the sacrificial layer 1, and by having a gap between two adjacent structural layers 3, the embossed portion 31 can be formed. Alternatively, the embossed portion 31 is formed by removing a part of the material of the structural layer 3. Specifically, a part of the material of the structural layer 3 can be removed using a gas etching process, thereby forming the embossed portion 31.

[0033] Also, the material of the structural layer 3 may be silicon oxide, metal oxide, or a material close to the thermal expansion coefficient material of silicon oxide. On the other hand, when the thermal expansion coefficient of the material of the structural layer 3 is close to the thermal expansion coefficient of the thin film 2, and / or when the thermal expansion coefficient of the material of the structural layer 3 is close to the thermal expansion coefficient of the sealing layer 4, due to the large difference in thermal expansion coefficients, material defect problems (such as holes, cracks, or delamination) are less likely to occur, reducing the possibility of poor sealing, and the operating reliability and service life of the manufactured MEMS device are high. On the other hand, the manufacturing method of the embodiment of the present application expands the manufacturing process of the structural layer 3 and reduces the limitations in the manufacturing of MEMS devices.

[0034] Here, the silicon oxide may include silica (SiO2), tetraethoxysilane (TEOS), polysilicon (Poly-Si). The polymer may include polyimide, silicon-on-glass bonding structure material, parylene, etc. The metal oxide may include alumina (Al2O3), titania (TiO2).

[0035] More specifically, in this embodiment, step S2 further includes step S2.1. As shown in FIGS. 7 to 8, after depositing the structural layer 3 on at least a part of the surface of the sacrificial layer 1, at least a part of the material covering the thin film 2 in the structural layer 3 is removed to form the embossed portion 31.

[0036] In this embodiment, as shown in FIGS. 7 to 8, the structural layer 3 is deposited on at least a part of the surface of the sacrificial layer 1. The structural layer 3 also covers the thin film 2. By removing at least a part of the material covering the thin film 2 in the structural layer 3, the embossed portion 31 is formed, whereby at least a part of the material of the thin film 2 is exposed through the embossed portion 31, facilitating the performance of step S3 (processing the through hole 21 in the thin film 2).

[0037] Here, in the embodiment, as shown in FIGS. 8 to 9, by removing a part of the material covering the thin film 2 in the structural layer 3, the structural layer 3 has a step 32, and the edge of the thin film 2 is located within the step 32, so that the structural layer 3 presses the edge of the thin film 2, reducing the possibility of the thin film 2 falling off from the embossed portion 31.

[0038] In another embodiment (not shown), by removing all of the material covering the thin film 2 in the structural layer 3, the embossed portion 31 is formed, there is no step 32, and the structural layer 3 does not press the edge of the thin film 2.

[0039] In the above embodiment, the material of the thin film 2 is one of a silicon-based material, a polymer material, or a metal material.

[0040] Here, the silicon-based materials may include silica (SiO2), silicon nitride (Si3N4), tetraethoxysilane (TEOS), polysilicon (Poly-Si), and amorphous silicon (a-Si). The polymer materials may include polyimide, silicon-on-glass bonding structure materials, and parylene. The metal materials may include alumina (Al2O3), titanium nitride (TiN), tantalum nitride (TaN), and titania (TiO2).

[0041] In the material of the thin film 2, a material close to the thermal expansion coefficient of the structural layer 3 can be selected to manufacture the thin film 2, or a material close to the thermal expansion coefficient of the sealing layer 4 can be selected to manufacture the thin film 2. Due to the large difference in thermal expansion coefficients, material defect problems (such as holes, cracks, or delamination) are less likely to occur, reducing the possibility of poor sealing and increasing the operating reliability and service life of the manufactured MEMS device. On the other hand, compared with the limitation of using silicon-based materials in the prior art methods, the manufacturing method of the embodiments of the present application expands the materials available for manufacturing the thin film 2, further expands the process methods capable of processing the through-hole 21, and reduces the manufacturing limitations of MEMS devices.

[0042] Here, when manufacturing the thin film 2 using a silicon-based material, the through-hole 21 can be manufactured using a dry etching process. When manufacturing the thin film 2 using a polymer material, the through-hole 21 can be manufactured using photolithography or a laser process. When manufacturing the thin film 2 using a metal material, the through-hole 21 can be manufactured using a wet etching process.

[0043] Also, when manufacturing the thin film 2 using a metal material, during the process of sealing the through-hole 21 of the thin film 2 by the sealing layer 4, the thin film 2 can withstand a higher temperature, and problems such as defects or delamination are less likely to occur, resulting in higher operating reliability and service life of the MEMS device.

[0044] In the above embodiment, as shown in FIGS. 3 to 4, in step S3, a through hole 21 is processed in the thin film 2 by laser drilling or surface ablation.

[0045] In this embodiment, as shown in FIGS. 3 to 4, a through hole 21 is manufactured in the thin film 2 by laser drilling or surface ablation. When the diameter of the through hole 21 is within the submicron range or the nanometer range, when the through hole 21 is sealed by the sealing layer 4, material defect problems (holes and cracks) are less likely to occur, and the problem of stratification between the sealing layer 4 and the thin film 2 is less likely to occur, and the manufactured MEMS device has higher operating reliability and a longer service life.

[0046] The method of the embodiment of the present application adjusts the size of the through hole 21 according to the area or depth dimension of the material to be removed in the sacrificial layer 1, and controls the time for the material to be removed in the sacrificial layer 1 to be discharged from the through hole 21, and its manufacturing process is flexible and can meet the usage requirements of different users.

[0047] In the above embodiment, the above steps are completed in a vacuum environment to manufacture the MEMS device, and thereby the moisture and / or organic gas in the chamber 11 are dried, so as to maintain the operating performance of the MEMS device at a stable level and improve the operating reliability and service life of the MEMS device.

[0048] In the above embodiment, the manufacturing method of the embodiment of the present application does not require planarization of the MEMS device, and is less likely to cause problems (such as holes, cracks or delamination) where defects exist in the oxide material, and the operating reliability and service life of the MEMS device are higher.

[0049] Utilizing the manufacturing method of the embodiments of the present application further has the following advantages. It is compatible with the Complementary Metal Oxide Semiconductor (CMOS) process, is easy to integrate with silicon-based fabrication flows, and helps to shorten the production cycle time.

[0050] The second aspect of the present application provides a MEMS device. As shown in FIG. 6, the MEMS device is manufactured using the manufacturing method of the above MEMS device, and the MEMS device includes a sacrificial layer 1, a thin film 2, a structural layer 3, and a sealing layer 4. The sacrificial layer 1 has a chamber 11. The thin film 2 is provided on the side where the chamber 11 of the sacrificial layer 1 is provided and covers the chamber 11. The thin film 2 has a through hole 21, and the through hole 21 communicates with the chamber 11. The structural layer 3 is provided on the side where the chamber 11 of the sacrificial layer 1 is provided. The sealing layer 4 includes a first sealing portion 41. The first sealing portion 41 is provided on the side of the thin film 2 away from the sacrificial layer 1, and the first sealing portion 41 closes the through hole 21. The MEMS device of the embodiments of the present application is manufactured by the manufacturing method described above and has the effects described above, which will not be elaborated here.

[0051] Specifically, as shown in FIG. 6, the structural layer 3 is provided with an embossed portion 31. The embossed portion 31 is adjacent to the side of the thin film 2 away from the sacrificial layer 1. The first sealing portion 41 is filled in at least a part of the space of the embossed portion 31 and is used to seal the through hole 21 of the thin film 2, thereby achieving the sealing of the chamber 11.

[0052] Here, in the embodiment, as shown in FIG. 6, the first sealing portion 41 can fill a part of the space of the embossed portion 31. In another embodiment (not shown), the first sealing portion 41 can fill all of the space of the embossed portion 31.

[0053] More specifically, as shown in FIG. 6, the sealing layer 4 further includes a second sealing portion 42, the second sealing portion 42 is provided on the side away from the sacrificial layer 1 of the structural layer 3, and the first sealing portion 41 and the second sealing portion 42 are connected by a connecting portion 43. The connecting portion 43 and the first sealing portion 41 surround to form a recessed portion.

[0054] In this embodiment, as shown in FIG. 6, the second sealing portion 42 is used to block the structural layer 3 from other substances, thereby ensuring the operating performance of the structural layer 3.

[0055] As shown in FIG. 6, the thickness of the structural layer 3 is larger than the thickness of the thin film 2. The thickness of the structural layer 3 is at the micron level, and the thickness of the thin film 2 is at the nanometer level. When the thickness of the thin film 2 is at the nanometer level, it is easy to observe the formation process of the chamber 11 in the sacrificial layer 1 and whether the inside of the chamber 11 is clean.

[0056] The above are only embodiments of the present invention, and those skilled in the art can make improvements without departing from the idea of the present invention, and all of these are included in the protection scope of the present invention.

Explanation of symbols

[0057] 10 Sacrificial layer 101 Chamber 20 Thin film 201 Through hole 30 Structural layer 40 Sealing layer 1 Sacrificial layer 11 Chamber 2 Thin film 21 Through hole 3 Structural layer 31 Embossed part 32 Step 4 Sealing layer 41 First sealing portion 42 Second sealing portion 43 Connecting portion

Claims

1. A method for manufacturing a MEMS device, comprising: depositing a thin film on at least a part of the surface of the sacrificial layer; depositing a structural layer on at least a part of the surface of the sacrificial layer so as to cover at least a part of the surface of the thin film and at least a part of the surface of the sacrificial layer not covered by the thin film; forming a relief pattern by removing at least a part of the material covering the thin film in the structural layer, and exposing at least a part of the material of the thin film through the relief pattern; processing a through-hole in the thin film; forming a chamber in the sacrificial layer by removing at least a part of the material covered by the thin film in the sacrificial layer and discharging the removed material from the through-hole; depositing a sealing layer on the surface of the thin film away from the sacrificial layer and sealing the through-hole. A method for manufacturing a MEMS device, characterized by comprising the above steps.

2. The method for manufacturing a MEMS device according to claim 1, wherein the material of the thin film is one of a silicon-based material, a polymer, or a metal.

3. The method for manufacturing a MEMS device according to claim 1, wherein the through-hole in the thin film is processed by laser drilling or surface ablation.

4. The method for manufacturing a MEMS device according to claim 1, wherein the manufacturing method of the MEMS device is completed in a vacuum environment.

5. A MEMS device, comprising: The MEMS device includes: a sacrificial layer having a chamber; a thin film provided on the side of the sacrificial layer where the chamber is provided, covering the chamber, having a through-hole, and the through-hole communicating with the chamber; Provided on the surface of the sacrificial layer located on the side where the chamber is provided, with a embossed pattern portion provided, and a structural layer adjacent to the side of the embossed pattern portion away from the sacrificial layer of the thin film, including a first sealing portion, the first sealing portion being provided on the side of the thin film away from the sacrificial layer, and the first sealing portion filling at least a part of the space of the embossed pattern portion, thereby including a sealing layer that closes the through hole, The sacrificial layer is a single-layer structure, and the MEMS device is characterized in this.

6. The sealing layer further includes a second sealing portion, and the second sealing portion is provided on the side of the structural layer away from the sacrificial layer, The first sealing portion and the second sealing portion are connected by a connecting portion, and the connecting portion and the first sealing portion surround to form a recessed portion. The MEMS device according to claim 5 is characterized in this.

7. The thickness of the structural layer is greater than the thickness of the thin film. The MEMS device according to claim 5 is characterized in this.

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