A thin film getter structure with micro-heater and a method for manufacturing the same

Abstract

The present application provides a thin film getter structure with a micro heater and a manufacturing method thereof, the thin film getter structure comprising: a substrate; a thermal sub formed on one main surface side of the substrate; and a getter film formed on the surface of the thermal sub, wherein the thermal sub comprises: a first insulating film; a thin film resistor formed on the upper surface of the first insulating film; and a second insulating film covering the thin film resistor, two ends of the thin film resistor being electrodes exposed from the second insulating film, the one main surface of the substrate having a cavity, the part of the thermal sub carrying the getter film being located above the cavity, and the part of the thermal sub carrying the getter film being supported on the one main surface around the cavity through a connecting part.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a thin-film getter structure with a micro heater and a method for manufacturing the same. Background Technology

[0002] Some semiconductor devices, especially some microelectromechanical systems (MEMS) devices, need to operate in a vacuum environment. For example, MEMS accelerometers, gyroscopes, and vacuum gauges with high-speed vibration components need to encapsulate the vibrating parts in a relatively stable vacuum. Similarly, MEMS pressure sensors that require a vacuum cavity also need a high and stable vacuum level within that cavity. Some infrared sensors also require encapsulation within a high-vacuum cavity.

[0003] On the one hand, achieving high-vacuum packaging is inherently challenging. This is because residual gas often remains within the vacuum chamber during the packaging process. Therefore, a getter is often introduced into the vacuum chamber, activated either during or after packaging, to absorb the residual gas and achieve the high vacuum required for device operation. A getter, also called a gas remover, is a material in vacuum technology that effectively adsorbs and fixes certain gas molecules. Getter materials are typically porous. When active gas molecules collide with the clean surface of the getter material, some molecules are adsorbed (physical adsorption), while others react chemically to form stable solid solutions (chemical adsorption). The gas molecules then diffuse further into the material, effectively removing a large amount of active gas. Activating the getter often requires heating it to several hundred degrees Celsius. Heating the entire packaged device from the outside requires the MEMS device itself, the packaging method, and the materials to withstand such high temperatures, which presents significant limitations. To address this issue, one technique involves coating a getter onto a resistance wire, connecting both ends of the resistance wire to conductive terminals on the package, and then activating the getter by energizing the resistance wire after packaging.

[0004] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0005] The inventors of this application believe that in existing heated getter structures, the activator is coated on the resistor wire, which often results in a large volume, making it unsuitable for scenarios with compact packaging space and also unsuitable for mass production.

[0006] This application provides a thin-film getter structure with a micro heater and a method for manufacturing the same. In this thin-film getter structure, the getter film is disposed on the surface of the heat element, the heat element is a stacked thin-film structure, and the thin film resistance thickness of the heat element is small. Therefore, the thickness of the thin-film getter structure can be reduced, which is beneficial for its miniaturization. Furthermore, the suspended structure of the heat element can prevent heat loss and improve the heating efficiency of the getter film.

[0007] According to one aspect of the embodiments of this application, a thin-film getter structure with a micro heater is provided, comprising:

[0008] substrate;

[0009] A heat source formed on one side of a main surface of the substrate; and

[0010] A getter film formed on the surface of the heat exchanger

[0011] The thermal electrons include:

[0012] First insulating film;

[0013] The thin-film resistance formed on the upper surface of the first insulating film; and

[0014] A second insulating film covering the thin-film resistor.

[0015] The two ends of the thin-film resistor are electrodes exposed from the second insulating film.

[0016] Wherein, one of the main surfaces of the substrate has a cavity.

[0017] The portion of the heat source that carries the getter film is located above the cavity.

[0018] The portion of the heat-carrying getter film is supported by a connector on one of the main surfaces surrounding the cavity.

[0019] According to another aspect of the embodiments of this application, a vacuum packaging structure for a microelectromechanical system (MEMS) device is provided, comprising:

[0020] A vacuum-sealed housing, wherein the interior of the vacuum-sealed housing is formed as a vacuum cavity;

[0021] Microelectromechanical systems (MEMS) devices encapsulated inside the vacuum-sealed housing;

[0022] A conductive terminal, one end of which is located inside the vacuum-sealed housing, and the other end of which is located outside the vacuum-sealed housing; and

[0023] The thin-film getter structure as described above in the embodiments is encapsulated inside the vacuum-sealed housing.

[0024] The electrodes of the thin-film resistor in the thin-film getter structure are electrically connected to the conductive terminal.

[0025] According to another aspect of the embodiments of this application, a method for manufacturing a thin-film getter structure having a micro heater is provided, comprising:

[0026] A thermal element is formed on one of the main surfaces of the substrate;

[0027] The heat magnet is etched to form a pattern of the connection portion and the portion of the heat magnet used to support the getter film, and one main surface of the substrate is etched to suspend the portion of the heat magnet used to support the getter film; and

[0028] A getter film is formed on the surface of the heat source;

[0029] The steps for forming the thermal electrons include:

[0030] A first insulating film is formed on one main surface of the substrate;

[0031] A thin-film resistor is formed on the upper surface of the first insulating film; and

[0032] A second insulating film is formed to cover the thin film resistor.

[0033] The two ends of the thin-film resistor are formed as electrodes exposed from the second insulating film.

[0034] The beneficial effects of this application are as follows: In the thin film getter structure, the getter film is disposed on the surface of the heat element, the heat element is a stacked thin film structure, and the thin film resistance thickness of the heat element is small. Therefore, the thickness of the thin film getter structure can be reduced, which is beneficial to its miniaturization. Furthermore, the suspended structure of the heat element can prevent heat loss and improve the heating efficiency of the getter film.

[0035] Specific embodiments of this application are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of this application can be adopted. It should be understood that the embodiments of this application are not limited in scope. Within the spirit and scope of the appended claims, embodiments of this application include many changes, modifications, and equivalents.

[0036] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0037] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0038] The accompanying drawings, which form part of the specification, are used to provide a further understanding of the embodiments of this application and illustrate the implementation methods of this application, together with the textual description, to explain the principles of this application. Obviously, the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0039] Figure 1 Another schematic diagram of the getter structure provided in this application;

[0040] Figure 2 Another schematic diagram of the getter structure provided in this application;

[0041] Figure 3 Another schematic diagram of the processing method for the getter structure provided in this application;

[0042] Figure 4 A schematic diagram of the application method of the getter structure provided in this application. Detailed Implementation

[0043] Referring to the accompanying drawings, the foregoing and other features of this application will become apparent from the following description. Specific embodiments of this application are specifically disclosed in the description and drawings, illustrating partial implementations in which the principles of this application may be employed. It should be understood that this application is not limited to the described embodiments; rather, it includes all modifications, variations, and equivalents falling within the scope of the appended claims.

[0044] In the following descriptions of the embodiments of this application: area refers to the area of ​​the film in the "lateral" direction, where "lateral" means a direction parallel to the substrate surface; "vertical" means a direction perpendicular to the substrate surface; in the "vertical" direction, the direction from the substrate to the heat source is the "up" direction, and the direction opposite to the "up" direction is the "down" direction; the surface of each layer structure along the "up" direction is the "upper surface", and the surface of each layer structure opposite to the "upper surface" is the "lower surface". The above-mentioned orientation settings are only for the convenience of explaining the technical solution of this application and do not represent the orientation of the thin film getter structure or vacuum encapsulation structure during processing and use.

[0045] Example 1

[0046] Embodiment 1 of this application provides another getter structure. This getter structure has its own heat source. Figure 1 This is a schematic diagram of this embodiment. In this embodiment, in order to highlight the main idea of ​​this application, Figure 1 The diagram only includes the most basic elements. Figure 1 a) is a plan view of the getter structure 100. Figure 1 b) is in Figure 1 A cross-sectional view of the getter structure 100 cut along the line marked AA' in a). Figure 1 c) is a planar view of the thin film resistor 3 of the getter structure 100.

[0047] like Figure 1 a) and Figure 1 As shown in b), the getter structure 100 includes: a substrate 1, a heat source 10 formed on the main surface 1a of the substrate 1, and a getter film 5 formed on the heat source 10. The heat source 10 includes a first insulating film 2 formed on the main surface 1a of the substrate 1, a conductive thin-film resistor 3 formed on the first insulating film 2, and a second insulating film 4 formed on the thin-film resistor 3. The second insulating film 4 has better thermal conductivity than the first insulating film 2. Furthermore, the area of ​​the getter film 5 is smaller than the area of ​​the second insulating film 4a. The overall area of ​​the getter structure 100 is designed according to the getter requirements. For example, the surface of the getter structure 100 is... Figure 1 The square shown in figure a has a side length of approximately 0.5-5 mm.

[0048] In this embodiment 1, the substrate 1 below the heat source 10 has a cavity 6. That is, the main part of the heat source 10 (i.e., the part carrying the getter film 5) is suspended above the cavity 6 and supported by a connecting part on the main surface of the substrate 1 surrounding the cavity 6. This connecting part is, for example, a cantilever beam 7 (e.g., including 7a, 7b, 7c, 7d), which can be connected to the main surface 1a of the substrate 1. The cantilever beam 7 can have two branches or more. For example, in this embodiment, the cantilever beam 7 includes four branches: 7a, 7b, 7c, and 7d. In this structure, the main part of the heat source 10 and the getter film 5 are separated from the rest of the area and connected only by the cantilever beam 7. Thus, the heat generated by the current flowing through the thin-film resistor 3 is lost only through the cantilever beam 7 in terms of solid-state conduction. By appropriately designing the width, length, and thickness of the cantilever beam, the solid-state conduction heat loss through the cantilever beam 7 can be made sufficiently small. As a result, compared to the case where the heat source is in contact with the main surface 1a of the substrate 1, the getter structure 100 of this embodiment can more effectively conduct the heat generated by the heat source to the getter film 5, thereby improving the heating efficiency required to activate the getter film 5. This is effective in saving heating energy and increasing the maximum heatable temperature.

[0049] The substrate 1 has two corresponding main surfaces, namely a first main surface 1a and a second main surface 1b. The substrate 1 can be a wafer commonly used in semiconductor manufacturing, such as a silicon wafer, a silicon-on-insulator (SOI) wafer, a germanium-silicon wafer, a germanium wafer, a gallium nitride wafer, a SiC wafer, etc., or it can be an insulating wafer such as quartz, sapphire, or glass. Alternatively, the substrate 1 can also be a wafer commonly used in semiconductor manufacturing, with various thin films and structures required for semiconductor devices and MEMS devices further formed on its surface. This embodiment is not limited in this respect. One specific example is that the substrate 1 is a silicon substrate with a thickness of approximately 700 micrometers and a diameter of approximately 200 mm. Furthermore, although this application describes the substrate 1 as a semiconductor substrate, this application is not limited to this, and the substrate 1 can also be replaced with a non-semiconductor substrate.

[0050] The first insulating film 2, formed on the main surface 1a of the substrate 1, has its material and thickness designed according to thermal performance requirements. It serves two main functions: first, to achieve electrical insulation between the conductive thin-film resistor 3 and the substrate 1; and second, to achieve thermal insulation between the thin-film resistor 3 and the substrate 1, allowing the heat generated when the thin-film resistor 3 is energized to flow effectively towards the getter film 5. For example, if the thermal insulation of the substrate 1 is insufficient, the thermal insulation of the first insulating film 2 can be significantly higher than that of the substrate 1. The first insulating film 2 can be a film composed of a single material, a composite film composed of multiple materials, or a composite film formed by stacking multiple films of single materials. For example, the first insulating film 2 can be a single film composed of silicon oxide. The thickness of the first insulating film 2 is, for example, 0.1-2 micrometers.

[0051] The thin-film resistor 3 formed on the first insulating film 2 can be designed according to the requirements for activating the getter film 5. The function of the thin-film resistor 3 is to generate a sufficiently high temperature after energizing to activate the getter film 5. Therefore, the material, shape, etc., of the thin-film resistor 3 can be designed according to the requirements for activating the getter film 5. The material of the thin-film resistor 3 must be able to withstand the temperature required to activate the getter film 5, and its resistance must be suitable for generating a sufficiently high temperature after appropriate energizing to activate the getter film 5. The material of the thin-film resistor 3 can be a metal. For example, the material of the thin-film resistor 3 is a metal containing one or more of Pt, W, Au, Al, Cu, Ni, Ta, Ti, and Cr. The material of the thin-film resistor 3 can be a semiconductor. For example, the material of the thin-film resistor 3 is polycrystalline silicon. When the material of the thin-film resistor 3 is polycrystalline silicon, it can be doped as needed to adjust its conductivity. The material of the thin-film resistor 3 can also be a metal compound. For example, the material of the thin-film resistor 3 is TiN or TaAlN. The thickness of the thin-film resistor 3 is, for example, 0.1-1 micrometers. The thin-film resistor 3 can be a continuous thin film or a thin film such as... Figure 1 The graphic thin films shown in a), b, and c.

[0052] For example, thin film resistor 3 is as follows Figure 1 The plan view of (c) shows a zigzag-shaped thin film. One end of the thin film resistor 3 is connected to electrode 3a via cantilever beam 7a, and the other end of the thin film resistor 3 is connected to electrode 3b via cantilever beam 7b. Electrodes 3a and 3b of the thin film resistor 3 are exposed through a window 4d opened in the second insulating film 4 for connection to an external power source (not shown).

[0053] The second insulating film 4, formed on the thin-film resistor 3, has its material and thickness designed according to thermal performance requirements. Its main functions are threefold: First, to achieve electrical insulation between the conductive thin-film resistor 3 and the getter film 5. Second, to concentrate the heat generated by the thin-film resistor 3 and conduct this heat to the getter film 5, allowing the temperature of the getter film 5 to reach its activation temperature. Third, to uniformly conduct the heat generated by the thin-film resistor 3 to the getter film 5. The thermal conductivity of the second insulating film 4 is superior to that of the first insulating film 2, which facilitates the effective conduction of the heat generated by the thin-film resistor 3 after energization to the getter film 5. The second insulating film 4 can be a film composed of a single material, a composite film composed of multiple materials, or a composite film formed by stacking multiple films of single materials. For example, the first insulating film 2 may be a single film composed of silicon oxide, and the second insulating film 4 may be a single film composed of silicon nitride. In this case, the elongation conditions of the first insulating film 2 and the second insulating film 4 are adjusted so that the thermal conductivity of the second insulating film 4 is higher than that of the first insulating film 2. The thickness of the second insulating film 4 is, for example, 0.1-2 micrometers. The second insulating film 4a, covering the main part of the conductive thin-film resistor 3, is separated from the remaining area of ​​the second insulating film 4b by an isolation groove 4c, allowing the heat generated by the thin-film resistor 3 to be effectively conducted to the getter film 5. The isolation groove 4c is a channel formed on the second insulating film 4, which runs through the upper and lower surfaces of the second insulating film 4 and reaches the surface of the underlying first insulating film 2. The isolation groove 4c is formed on the periphery of the thin-film resistor 3.

[0054] The first insulating film 2, the thin film resistor 3 formed on the first insulating film 2, and the second insulating film 4 formed on the thin film resistor 3 constitute the heat source 10.

[0055] The getter film 5 formed on the heat exchanger 10 is composed of a getter material. The material, area, and thickness of the getter film 5 are designed based on factors such as the type and quantity of gases to be adsorbed. The area of ​​the getter film 5 is smaller than the area of ​​the second insulating film 4a so that the getter film 5 can be effectively activated by the second insulating film 4a. For example, the getter film 5 can be a Zr-based non-evaporable getter, including materials such as ZrVFe, ZrAl, and ZrC. The getter film 5 can also be a Ti-based non-evaporable getter, including materials such as Ti-Mo. The size and proportion of pores in the getter film 5 can be appropriately adjusted. For example, the pore size of the getter film 5 can be above 40%. The thickness of the getter film 5 is, for example, around 0.1-5 micrometers.

[0056] The getter structure 100 described above allows the getter film 5 to reach a maximum temperature of 200℃-1000℃ during activation. The getter structure 100 can be optimized overall according to the required activation temperature, particularly the design of the heat source 10. For example, the design of the film structure composed of the heat source 10 and the getter film 5 needs to appropriately consider overall stress to prevent the getter structure 100, especially the cantilever beam 7, from breaking due to stress during manufacturing and use. The cantilever beam 7 must also have sufficient strength to support the film structure composed of the heat source 10 and the getter film 5, ensuring its proper levitation.

[0057] As described above, this embodiment provides a small-volume, self-heating thin-film getter structure, which reduces the volume occupied by a small vacuum cavity. This structure is also readily mass-producible because it can be fabricated using semiconductor processes. Furthermore, because the thin-film getter structure of this embodiment has its own heat source, the getter can be activated at any time when needed, effectively adsorbing the gas that accumulates in the vacuum cavity over time, extending the lifespan of the MEMS devices sealed within the vacuum cavity. In the structure of Embodiment 1, the main part of the heat source 10 and the getter film 5 are connected to the remaining areas only by the cantilever beam 7, minimizing the heat loss due to solid-state conduction caused by the energization of the thin-film resistor 3. As a result, the getter structure of this embodiment more effectively conducts the heat generated by the heat source to the getter film, improving the heating efficiency required to activate the getter film, thus saving heating energy and increasing the maximum heatable temperature.

[0058] Example 2

[0059] Embodiment 4 of this application provides another getter structure. This getter structure has a built-in MEMS thermal core. Figure 2 This is a plan view of this embodiment. In this embodiment, in order to highlight the main idea of ​​this application, Figure 2 The schematic diagram only includes the most basic elements. For aspects of this embodiment 2 that are similar to those of embodiment 1, please refer to embodiment 1; they will not be described in detail here.

[0060] In Example 1, the getter structure 100 has two or more getter structure units consisting of a heat source 10 and a getter film 5 formed thereon. For example, such as Figure 2As shown, the getter structure 100 has two getter structure units. Each getter structure unit has a similar structure to the getter structure 100 of Example 1. The getter film 5-1 of the first getter structure unit corresponds to one heat source 10-1, and the getter film 5-2 of the second getter structure unit corresponds to another heat source 10-2. Heat sources 10-1 and 10-2 can be completely independent. However, to save power input terminals, heat sources 10-1 and 10-2 can share a single electrode 3c. This structure allows heat source 10-1 to be independently energized via electrodes 3-1a and 3c, and heat source 10-2 to be independently energized via electrodes 3-2a and 3c. That is, getter film 5-1 and getter film 5-2 can be independently activated by heating.

[0061] In addition to the effects of Example 1, the getter structure of this embodiment can also more effectively activate the independent thin-film getters at different time points, thereby extending the service life of MEMS devices sealed together in a vacuum chamber.

[0062] Example 3

[0063] Embodiment 3 of this application provides another method for manufacturing a getter structure. Figure 3 This is a cross-sectional schematic diagram of this embodiment. The manufacturing method of this embodiment can be used to manufacture... Figure 1 The described embodiment 1 and Figure 2 The getter structure 100 of Example 2 is described. In this embodiment, in order to highlight the main idea of ​​this application, Figure 3 The schematic diagram only includes the most basic elements. The structures and materials involved in this Embodiment 3 are the same as those in Embodiments 1 and 2, and will not be described in detail here. For simplicity, this Embodiment 3 uses the getter structure 100 of Embodiment 1 as an example to describe the manufacturing method.

[0064] The manufacturing method of the getter structure 100 provided in this embodiment 3 includes: forming a heat element 10 on a main surface 1a of a substrate 1, and forming a getter film 5 on the heat element 10. Furthermore, the manufacturing method further includes: before forming the getter film 5 on the surface of the heat element, etching the heat element 10 to form a pattern of a connecting portion and a portion of the heat element used to support the getter film 5, and etching the main surface 1a of the substrate 1 to suspend the portion of the heat element 10 used to support the getter film 5, for example: processing the heat element 10 and the substrate 1 to form a cavity below the heat element 10, and connecting it to the substrate 1 via cantilever beams 7 (including 7a, 7b, 7c, and 7d). The manufacturing method will now be described step by step.

[0065] First, such as Figure 3As shown in a), substrate 1 is prepared. In this embodiment, substrate 1 has two corresponding main surfaces, namely a first main surface 1a and a second main surface 1b. Substrate 1 is the substrate 1 described in Embodiment 2. For simplicity and convenience, this embodiment is described using a Si substrate, which is conventionally used in semiconductor processes, as an example.

[0066] Then, as Figure 3 As shown in b), a first insulating film 2 is formed on a main surface 1a of the substrate 1. The first insulating film 2 is the first insulating film 2 described in Example 2. For example, the first insulating film 2 is a silicon oxide film with a thickness of 0.4 micrometers, formed using conventional TEOS CVD (TEOS: Tetraethyl orthosilicate; CVD: Chemical Vapor Deposition) and associated processes.

[0067] Then, as Figure 3 As shown in c), a conductive thin-film resistor 3 is formed on the first insulating thin film 2. The conductive thin-film resistor 3 is the conductive thin-film resistor 3 described in Example 1. For example, the conductive thin-film resistor 3 is made of metal Pt with a thickness of 0.2 micrometers and is formed using a conventional magnetron sputtering process.

[0068] Then, as Figure 3 As shown in d), the conductive thin-film resistor 3 is processed to form Figure 1 The zigzag conductive thin-film resistor 3 shown in (c) includes electrodes 3a and 3b at both ends. The conductive thin-film resistor 3 was fabricated using conventional photolithography and ion beam etching (IBE) methods.

[0069] Then, as Figure 3 As shown in e), a second insulating film 4 is formed on the thin-film resistor 3. The second insulating film 4 is the second insulating film 4 described in Example 2. For example, the second insulating film 4 is a silicon nitride film with a thickness of 0.4 micrometers, and the film is grown using conventional PECVD (Plasma Enhanced Chemical Vapor Deposition) methods.

[0070] Then, as Figure 3 f) and Figure 1As shown in a), the second insulating film 4 and the first insulating film 2 below it are processed to form a channel 8 and a window 4d. The channel 8 penetrates the second insulating film 4 and the first insulating film 2 below it in the depth direction, and the bottom exposes the first main surface 1a of the substrate 1. The window 4d penetrates the second insulating film 4 in the depth direction, and the bottom exposes the surfaces of electrodes 3a and 3b. The processing of the second insulating film 4 and the first insulating film 2 below it can be performed separately or continuously. When performed separately, the second insulating film 4 can be etched using conventional photolithography and silicon nitride etching and supporting processes, and then photolithography can be performed again and silicon oxide etching and supporting processes can be used to etch the first insulating film 2. When performed continuously, only conventional photolithography can be performed once, and then dry etching and supporting processes can be used to continuously etch the second insulating film 4 and the first insulating film 2.

[0071] Then, as Figure 3 g) and Figure 1 As shown in a), the substrate 1 is processed to form a cavity 6 below the heat source 10, and simultaneously form cantilever beams 7 (including 7a, 7b, 7c, and 7d). This suspends the heat source 10 in the air, connecting it to the substrate 1 only through the cantilever beams 7. The substrate 1 can be processed using conventional silicon processing techniques. For example, silicon can be etched using a gas or plasma that has an etching effect on silicon. In this case, the gas or plasma reaches the surface of the substrate 1 through the channel 8 for etching. Examples of gases include XeF2 or SF6. Examples of plasmas include SF6 plasma. Alternatively, silicon can be etched using a liquid that has an etching effect on silicon. In this case, the gas or plasma also reaches the surface of the substrate 1 through the channel 8 for etching. Examples of liquids include KOH (potassium hydroxide) and TMAH (tetramethylammonium hydroxide).

[0072] Through such Figure 3 b) to Figure 3 The process shown in g) forms a heat element 10 consisting of a first insulating film 2, a conductive thin-film resistor 3 formed on the first insulating film 2, and a second insulating film 4a covering the main part of the conductive thin-film resistor 3. The heat element 10 is suspended in the air and connected to the substrate 1 only through a cantilever beam 7.

[0073] Then, as Figure 3 h) and Figure 1 As shown in a), a getter film 5 is formed on top of the heat source 10. The getter film 5 is the getter film 5 described in Example 2. The area of ​​the getter film 5 is smaller than the area of ​​the second insulating film 4a. For example, the getter film 5 is a Ti-based non-evaporable getter material including Ti-Mo, with a thickness of approximately 2 micrometers. The getter film 5 can be deposited on top of the second insulating film 4a using the magnetron sputtering method with a metal mask described in Example 5.

[0074] Obviously, using Figure 3 The method for manufacturing the described getter structure 5 can be used not only to manufacture the single-unit getter structure 5 shown in Example 1, but also to manufacture the multiple-unit getter structure 5 shown in Example 2.

[0075] As described above, this embodiment provides another method for manufacturing a getter structure, suitable for manufacturing the getter structures shown in Embodiments 1 and 2. The manufacturing method is simple and has low manufacturing cost. Multiple getter structures can be manufactured simultaneously on a single semiconductor substrate, enabling mass production.

[0076] Example 4

[0077] Embodiment 4 of this application provides a vacuum packaging structure for a MEMS device. Figure 4 This is a cross-sectional schematic diagram of this embodiment. In this embodiment, in order to highlight the main idea of ​​this application, Figure 4 The diagram only includes the most basic elements.

[0078] like Figure 4 As shown, the vacuum packaging structure 200 of the MEMS device in an embodiment of this application includes: a vacuum packaging housing 30 (including 30a and 30b), conductive terminals 32 (including 32a and 32b) connecting the inside and outside of the vacuum packaging housing 30b, a MEMS device 20 encapsulated inside the vacuum packaging housing 30, and a getter structure 100. The electrode 3 (not shown) of the getter structure 10 is electrically connected to the conductive terminal 32b via a wire 31b. A vacuum cavity 40 is formed inside the vacuum packaging housing 30.

[0079] The vacuum packaging housing 30 consists of housing 30a and housing 30b, and conductive terminals 32 (including 32a and 32b) connecting the inside and outside of the vacuum packaging housing 30b. The vacuum packaging housing 30 is a standard component used for vacuum packaging of semiconductor devices and MEMS devices, forming a vacuum cavity 40 after packaging. The initial vacuum level of the vacuum cavity 40 meets the vacuum level required for the normal operation of the MEMS device 20. The conductive terminals 32a are multiple conductive terminals, each connected to one of the electrodes of the MEMS device 20. The conductive terminals 32b are multiple conductive terminals, each connected to one of the electrodes of the getter structure 100.

[0080] MEMS device 20 is a MEMS device that needs to operate in a certain vacuum atmosphere. For example, MEMS device 20 can be one or more of the following MEMS devices: MEMS oscillator, MEMS pressure sensor, MEMS resonant filter, MEMS inertial sensor (MEMS gyroscope and MEMS accelerometer, etc.), MEMS infrared imaging device, etc. Each electrode of MEMS device 20 is electrically connected to different conductive terminals 32a through different wires 31a.

[0081] The getter structure 100 is the getter structure 100 described in Example 1 or 2. There may be one or more getter structures 100. Each getter structure 100 may contain a single getter structure unit as shown in Example 1, or it may contain a plurality of getter structure units as shown in Example 2. Each electrode of the getter structure 100 is electrically connected to a different conductive terminal 32b via a different wire 31b.

[0082] At least one getter structure unit of the getter structure 100 can be activated immediately after the vacuum packaging structure 200 is completed, absorbing residual gas in the vacuum cavity 40 to ensure the vacuum level of the vacuum cavity 40 meets the operating requirements of the MEMS device 20. At least one getter structure unit of the getter structure 100 can also be activated after a certain period of time following the completion of the vacuum packaging structure 200, absorbing gas generated or entering the vacuum cavity 40 to restore the degraded vacuum level of the vacuum cavity 40 to meet the operating requirements of the MEMS device 20. Activation of the getter film 5 can be achieved by supplying electrical energy to the heat exchanger 10 via the conductive terminal 32b, thereby raising the temperature of the getter film 5 to its activation temperature. By simultaneously vacuum-packing multiple getter structure units with the MEMS device 20 using at least one getter structure unit, the getter film 5 can be activated promptly when needed. Thus, compared to situations where the getter can only be activated once, this embodiment allows the MEMS device 20 to remain in a more ideal vacuum environment for a longer period. This means that not only can the performance stability and reliability of MEMS devices be improved, but the lifespan of the MEMS devices and the entire vacuum packaging structure containing them be extended several times, thereby reducing usage costs. Furthermore, each getter structural unit, due to its built-in heat source 10, can have its getter film 5 activated multiple times. Although the getter effect of the getter film 5 will decrease after the second activation compared to the first activation, it can still improve the vacuum level inside the vacuum chamber 40.

[0083] As described above, the MEMS device packaging structure provided in this embodiment, by incorporating a tiny heat source, can activate the getter structure at any time when needed, thereby improving the performance stability and reliability of the MEMS device, extending its lifespan, and reducing its operating costs. Because the heat source and getter film are integrated and have a small volume, space can be saved in the MEMS device packaging structure.

[0084] The present application has been described above with reference to specific embodiments. However, those skilled in the art should understand that these descriptions are exemplary and not intended to limit the scope of protection of the present application. Those skilled in the art can make various modifications and variations to the present application based on its spirit and principles, and these modifications and variations are also within the scope of the present application.

Claims

1. A thin film getter structure with a micro heater, comprising: a substrate; a thermal sub formed on one main surface side of the substrate; and a getter thin film formed on a surface of the thermal sub, wherein the thermal sub comprises: a first insulating thin film; a thin film resistor formed on an upper surface of the first insulating thin film; and a second insulating thin film covering the thin film resistor, both ends of the thin film resistor being electrodes exposed from the second insulating thin film, wherein the one main surface of the substrate has a hollow, a portion of the thermal sub carrying the getter thin film is located above the hollow, the portion of the thermal sub carrying the getter thin film is supported on the one main surface around the hollow by a connecting portion, a thermal conductivity of the second insulating thin film is higher than a thermal conductivity of the first insulating thin film, the first insulating thin film is an oxide of silicon and the second insulating thin film is a nitride of silicon, wherein the thin film getter structure comprises two thermal subs and two getter thin films provided on the same main surface side of the substrate, each of the getter thin films being provided on an upper surface of the corresponding thermal sub, the two thermal subs share one electrode.

2. The thin film getter structure according to claim 1, wherein the second insulating thin film comprises a first portion and a second portion, the first portion and the second portion being separated from each other by a separation groove, the first portion covers an area of the thin film resistor.

3. The thin film getter structure according to claim 2, wherein an area of the getter thin film formed on the first portion of the second insulating thin film is smaller than an area of the first portion of the second insulating thin film.

4. A vacuum packaging structure of a micro electro mechanical system device, comprising: a vacuum packaging case, an inside of the vacuum packaging case being formed as a vacuum cavity; a micro electro mechanical system device packaged inside the vacuum packaging case; a conductive terminal, one end of which is located inside the vacuum packaging case and the other end of which is located outside the vacuum packaging case; and a thin film getter structure according to any one of claims 1 to 3, which is packaged inside the vacuum packaging case, wherein an electrode of the thin film resistor of the thin film getter structure is in electrical communication with the conductive terminal.

5. A manufacturing method of a thin film getter structure with a micro heater, comprising: forming a thermal sub on one main surface of a substrate; etching the thermal sub to form a pattern of a connecting portion and a portion of the thermal sub for carrying a getter thin film, and etching the one main surface of the substrate so that the portion of the thermal sub for carrying the getter thin film is suspended; and forming the getter thin film on a surface of the thermal sub, wherein the step of forming the thermal sub comprises: forming a first insulating thin film on the one main surface of the substrate; forming a thin film resistor on an upper surface of the first insulating thin film; and forming a second insulating thin film covering the thin film resistor, wherein both ends of the thin film resistor are formed as electrodes exposed from the second insulating thin film, a thermal conductivity of the second insulating thin film is higher than a thermal conductivity of the first insulating thin film, the first insulating thin film is an oxide of silicon and the second insulating thin film is a nitride of silicon. wherein, the thin film getter structure includes two of the hot junctions and two of the getter films disposed on the same side of the main face of the substrate, each of the getter films being disposed on the upper surface of a corresponding one of the hot junctions, the two hot junctions share one electrode.

6. The manufacturing method of claim 5, wherein, the step of forming the hot junctions further comprises: forming an isolation groove in the second insulating film, the isolation groove separating a first portion and a second portion of the second insulating film from each other, wherein the first portion covers the area of the thin film resistor.

7. The manufacturing method of claim 6, wherein, the area of the getter film formed on the first portion of the second insulating film is smaller than the area of the first portion of the second insulating film.

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