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, both ends of the thin film resistor being electrodes exposed from the second insulating film.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor technology, and in particular to a thin film getter structure with a micro heater and a manufacturing method thereof. BACKGROUND

[0002] Some semiconductor devices, especially some micro electro mechanical systems (MEMS) devices, need to be packaged to work in a vacuum environment. For example, MEMS acceleration sensors, gyroscopes, and vacuum gauges with high-speed vibrating parts need to package the vibrating parts in a relatively stable vacuum. For example, MEMS pressure sensors also need a vacuum cavity with a relatively high vacuum and stable vacuum degree. Some infrared sensors also need to be packaged in a relatively high vacuum cavity.

[0003] On the one hand, it is challenging to achieve a relatively high vacuum package. Because, during the packaging process, some residual gas often remains in the vacuum cavity. Therefore, it is often necessary to seal a getter in the vacuum cavity, activate the getter during packaging, or activate the getter after packaging is completed to absorb the residual gas in the vacuum cavity and achieve a relatively high vacuum required for device operation. Getter, also known as gas absorber, refers to a material that can effectively absorb and fix some or certain gas molecules in the field of vacuum technology. The getter material is usually a porous structure. When active gas molecules collide with the surface of the clean getter material, some gas molecules are adsorbed, which is physical adsorption of the getter material; some gas molecules will react with the getter material to form stable solid solutions, which is chemical adsorption of the getter material. And the gas molecules continue to diffuse into the material, so as to achieve the purpose of removing a large amount of active gas. Activating the getter often requires heating the getter to a high temperature of hundreds of degrees. If the entire packaged device is heated from the outside, the MEMS device itself and the packaging method and material must be able to withstand such high temperatures, thus having great limitations. In order to solve this problem, one technology coats the getter on a resistance wire, connects the two ends of the resistance wire to the conductive terminals of the packaging shell, and heats the getter by passing current through the resistance wire after packaging to activate the getter.

[0004] It should be noted that the above introduction to the technical background is only for the convenience of clearly and completely describing the technical solutions of the present application, and for the convenience of understanding by those skilled in the art. The above technical solutions cannot be considered as known to those skilled in the art only because they are described in the background section of the present application. SUMMARY

[0005] The inventor of the present application believes that in the existing band heat sub getter structure, the activator is often coated on the resistance wire, which is too large in volume and not suitable for compact packaging space and mass production.

[0006] The embodiment of the present application provides a thin film getter structure with a micro heater and a manufacturing method thereof. In the thin film getter structure, a getter film is arranged on the surface of a heat sub, the heat sub is a laminated film structure, and the film resistance thickness of the heat sub is small. Therefore, the thickness of the thin film getter structure can be reduced, and the miniaturization of the thin film getter structure is facilitated.

[0007] According to an aspect of the embodiment of the present application, a thin film getter structure with a micro heater is provided, comprising:

[0008] a substrate;

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

[0010] a getter film formed on the surface of the heat sub,

[0011] wherein the heat sub comprises:

[0012] a first insulating film;

[0013] a film resistance formed on the upper surface of the first insulating film; and

[0014] a second insulating film covering the film resistance,

[0015] two ends of the film resistance are electrodes exposed from the second insulating film.

[0016] According to another aspect of the embodiment of the present application, a vacuum packaging structure of a micro electro mechanical system device is provided, comprising:

[0017] a vacuum packaging shell, the inside of the vacuum packaging shell is formed into a vacuum cavity;

[0018] a micro electro mechanical system device packaged in the inside of the vacuum packaging shell;

[0019] a conductive terminal, one end of the conductive terminal is located in the inside of the vacuum packaging shell, and the other end of the conductive terminal is located outside the vacuum packaging shell; and

[0020] a thin film getter structure as described in the above aspect of the embodiment, which is packaged in the inside of the vacuum packaging shell,

[0021] wherein the electrodes of the film resistance of the thin film getter structure are in electrical communication with the conductive terminal.

[0022] According to still another aspect of the embodiment of the present application, a manufacturing method of a thin film getter structure with a micro heater is provided, comprising:

[0023] forming a heat sub on one main surface of a substrate; and

[0024] forming a getter film on the surface of the heat sub;

[0025] wherein the step of forming the heat sub comprises:

[0026] forming a first insulating film on one main surface of a substrate;

[0027] forming a thin film resistor on the upper surface of the first insulating film; and

[0028] forming a second insulating film covering the thin film resistor,

[0029] wherein both ends of the thin film resistor are formed as electrodes exposed from the second insulating film.

[0030] The thin film getter structure has the getter film arranged on the surface of the heat sub, the heat sub is a laminated thin film structure, and the thin film resistor of the heat sub has a small thickness, thereby reducing the thickness of the thin film getter structure and facilitating miniaturization.

[0031] Specific embodiments of the application are disclosed herein, and represented in the accompanying drawings, illustrating the principles of the application in a manner that is best suited to the understanding of its principles and the practices of its application. It should be understood that the embodiments of the application are not limited in scope to the specific embodiments disclosed herein. In the scope of the appended claims and their equivalents, the embodiments of the application include numerous changes, modifications and equivalents.

[0032] Features described and / or illustrated with respect to one embodiment can be used in the same or similar manner in one or more other embodiments, in combination with or in place of features in other embodiments, or in place of other features.

[0033] It should be emphasized that the term "comprises / comprising" when used in this specification is taken to mean the presence of stated features, integers, steps or components but not the exclusion of one or more other features, integers, steps, components or groups thereof. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0035] Figure 1A schematic diagram of a getter structure provided by the present application;

[0036] Figure 2 A schematic diagram of a getter structure provided by the present application;

[0037] Figure 3 A schematic diagram of a getter structure provided by the present application;

[0038] Figure 4 A schematic diagram of a getter structure provided by the present application;

[0039] Figure 5 A schematic diagram of a getter structure provided by the present application;

[0040] Figure 6 A schematic diagram of a getter structure provided by the present application;

[0041] Figure 7 A schematic diagram of a getter structure provided by the present application; DETAILED DESCRIPTION

[0042] The foregoing and other features of the present application will become apparent to those skilled in the art upon consideration of the following description of specific embodiments of the application, taken in conjunction with the accompanying drawings. In the description of embodiments of the application, specific terminology is employed for the sake of clarity. However, the application is not intended to be limited to the specific embodiments described, but is to be understood to include all modifications, equivalents, and alternatives that fall within the scope of the appended claims.

[0043] In the following description of the embodiments of the present application: the area refers to the area of the thin film in the "lateral" direction, wherein the "lateral" direction represents the direction parallel to the surface of the substrate; the "vertical" direction represents the direction perpendicular to the surface of the substrate; in the "vertical" direction, the direction from the substrate to the hot spot 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 setting of the direction is only for the convenience of describing the technical solutions of the present application, and does not represent the orientation of the getter structure of the thin film or the vacuum packaging structure during processing and use.

[0044] Example 1

[0045] Example 1 of the present application provides a getter structure. This getter structure has a hot spot. Figure 1 is a schematic diagram of the present embodiment. In the present embodiment, in order to highlight the main idea of the present application, Figure 1 The schematic diagram of only includes the most basic elements. Figure 1 a) of is a plan view of the getter structure 100, Figure 1b) is a cross-sectional view of the getter structure 100 cut along the line indicated by AA' in Figure 1 c) is a plan view of the thin film resistor 3 of the getter structure 100. Figure 1 c) is a plan view of the thin film resistor 3 of the getter structure 100.

[0046] As shown in Figure 1 a) and Figure 1 b), the getter structure 100 includes a substrate 1, a thermal sub 10 formed on a main surface la of the substrate 1, and a getter film 5 formed on the thermal sub 10. The thermal sub 10 includes a first insulating film 2 formed on the main surface la 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 can have a higher thermal conductivity than the first insulating film 2, i.e., the second insulating film 4 can have a higher thermal conductivity than the first insulating film 2. A second insulating film 4a covering a major portion of the conductive thin film resistor 3 is separated from a second insulating film 4b in the remaining area by an isolation groove 4c. The area of the getter film 5 is smaller than the area of the second insulating film 4a. The area of the getter structure 100 as a whole is designed according to the gettering requirement. For example, the surface of the getter structure 100 is a square as shown in Figure 1 a), and one side of the square has a length in the range of about 0.5 to 5 mm. In the present application, the second insulating film 4a covering a major portion of the conductive thin film resistor 3 can be referred to as a first portion of the second insulating film 4a, and the second insulating film 4b in the remaining area can be referred to as a second portion of the second insulating film 4a.

[0047] The substrate 1 has two corresponding main surfaces, i.e., a first main surface la and a second main surface lb. The substrate 1 can be a wafer commonly used in the semiconductor manufacturing field, such as a silicon wafer, a silicon-on-insulator (SOI) wafer, a germanium-silicon wafer, a germanium wafer, or a gallium nitride wafer, a SiC wafer, etc., or an insulating wafer such as quartz, sapphire, glass, etc. In addition, the substrate 1 can be a wafer commonly used in the semiconductor manufacturing field, and further have various films and structures required for semiconductor devices and MEMS devices on the surface of the wafer. The present embodiment is not limited in this regard. In one specific example, the substrate 1 is a silicon substrate having a thickness of about 700 micrometers and a diameter of about 200 mm. In addition, although the substrate 1 is described as a semiconductor substrate in each of the embodiments of the present application, the present application is not limited thereto, and the substrate 1 can be replaced with a non-semiconductor substrate. In addition, in Embodiment 1 and Embodiments 3 and 5 described below, the substrate 1 is preferably an insulating substrate such as a glass substrate, etc.

[0048] The first insulating film 2 formed on the main surface la of the substrate 1 is designed in terms of material and thickness according to the thermal sub- performance requirement. It has two main functions. One is to achieve electrical insulation between the conductive thin film resistor 3 and the substrate 1. The other is to achieve thermal insulation between the thin film resistor 3 and the substrate 1, so that the heat generated by the thin film resistor 3 after energization effectively flows in the direction of the getter film 5. For example, if the thermal insulation of the substrate 1 is not sufficient, the thermal insulation of the first insulating film 2 can be sufficiently higher than that of the substrate 1. The first insulating film 2 can be a single material film, a composite film of multiple materials, or a composite film formed by laminating multiple single material films. For example, the first insulating film 2 is a single film composed of silicon oxide. The thickness of the first insulating film 2 is, for example, 0.1 to 2 micrometers.

[0049] The thin film resistor 3 functions to generate a sufficiently high temperature to activate the getter film 5 after energization. Therefore, the material, shape, etc. of the thin film resistor 3 can be designed according to the requirement to activate 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 the resistance must be appropriately sized to generate a sufficiently high temperature to activate the getter film 5 after appropriate energization. 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 polysilicon. When the material of the thin film resistor 3 is polysilicon, the polysilicon can be doped as needed to adjust the 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 to 1 micrometers. The thin film resistor 3 can be a continuous film or a patterned film as shown in a), b, and c of FIG. 6, for example. For example, the thin film resistor 3 is a zigzag-shaped film as shown in the plan view of c) of FIG. 6. The electrodes 3a and 3b of the thin film resistor 3 are exposed through the windows 4d formed in the second insulating film 4, so as to be connected to an external power source (not shown), for example, the two ends of the thin film resistor 3 are the electrodes 3a and 3b exposed from the second insulating film 4. Figure 1 Figure 1

[0050] ​​The second insulating film 4 formed on the thin film resistance 3 is designed in material and thickness according to the need of the thermal sub. It has three main functions. One is to realize the electrical insulation between the conductive thin film resistance 3 and the getter film 5. The second is to gather the heat generated by the thin film resistance 3 and conduct it to the getter film 5, so that the temperature of the getter film 5 reaches its activation temperature. The third is to conduct the heat generated by the thin film resistance 3 to the getter film 5 uniformly. The heat conduction capacity of the second insulating film 4 is superior to that of the first insulating film 2, which is beneficial to the effective conduction of the heat generated by the thin film resistance 3 to the getter film 5 after the thin film resistance 3 is electrified. The second insulating film 4 can be a single material film, a composite film composed of multiple materials, or a composite film composed of multiple single material films stacked together. For example, the first insulating film 2 is a single film composed of silicon oxide, and the second insulating film 4 is a single film composed of silicon nitride. At this time, the long film conditions of the first insulating film 2 and the second insulating film 4 are adjusted so that the heat conduction 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 microns. The second insulating film 4a covering the main part of the conductive thin film resistance 3 is separated from the second insulating film 4b in the rest of the area by the isolation groove 4c, so that the heat generated by the thin film resistance 3 is effectively conducted to the getter film 5. The isolation groove 4c is a channel formed on the second insulating film 4, which penetrates through the upper and lower surfaces of the second insulating film 4 to reach the surface of the underlying first insulating film 2. The isolation groove 4c is formed at the periphery of the thin film resistance 3.

[0051] The first insulating film 2, the thin film resistance 3 formed on the first insulating film 2, and the second insulating film 4 formed on the thin film resistance 3 constitute the thermal sub 10.

[0052] The getter film 5 formed on the thermal sub 10 is composed of a getter material. The material, area and thickness of the getter film 5 are designed according to factors such as the type and amount of gas to be adsorbed. The area of the getter film 5 is smaller than that of the second insulating film 4a, so that the getter film 5 can be effectively activated through 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, ZrC, etc. The getter film 5 can be a Ti-based non-evaporable getter, including materials such as Ti-Mo, etc. The size and proportion of the pores of the getter film 5 can be adjusted appropriately. For example, the proportion of the pores of the getter film 5 is above 40%. The thickness of the getter film 5 is, for example, about 0.1-5 microns.

[0053] The getter structure 100 as described above can make the maximum temperature reached by the getter film 5 during the activation process to be in the range of 200-1000°C. The getter structure 100 can be designed as a whole to meet the actual required activation temperature, especially the design of the heat sub 10. The film structure composed of the heat sub 10 and the getter film 5 needs to be designed to properly consider the stress of the whole film, so that the getter structure 100 will not be damaged by stress during the manufacturing and using processes.

[0054] In addition, in some embodiments of the present application, the surface of the substrate 1 can have a concave cavity, which can be located at the lower side of the heat sub, so that the heat generated by the heat sub can be more concentratedly transferred to the getter film 5, improving the heating efficiency of the getter film.

[0055] As described above, the present embodiment provides a small-sized film getter structure with a heat sub. Such a structure can reduce the occupation of the volume of the micro vacuum cavity. Such a structure can also have good mass productivity because it can be processed by a semiconductor process. In addition, the film getter structure of the present embodiment can activate the film getter at any time when needed because it has a heat sub, effectively adsorbing the gas increasing over time in the vacuum cavity, and prolonging the service life of the MEMS device sealed in the vacuum cavity.

[0056] Embodiment 2

[0057] Embodiment 2 of the present application provides another getter structure. Such a getter structure has a heat sub. Figure 2 is a schematic view of the present embodiment. In the present embodiment, in order to highlight the main idea of the present application, Figure 2 the schematic view of only includes the most basic elements. Figure 2 a) of is a plan view of the getter structure 100, Figure 2 b) of is a cross-sectional view of the getter structure 100 taken along the line AA' indicated in a) of Figure 2 a) of is a cross-sectional view of the getter structure 100 taken along the line AA' indicated in a) of Figure 2 c) of is a plan view of the film resistor 3 of the getter structure 100. For the sake of simplicity, the similar contents as in Embodiment 1 will not be described in detail in the present embodiment.

[0058] As described above, Figure 2 a) and Figure 2The getter structure 100 comprises a substrate 1, a thermal sub 10 formed on the main surface la of the substrate 1, and a getter film 5 formed on the thermal sub 10. The thermal sub 10 comprises a first insulating film 2 formed on the main surface la of the substrate 1, a conductive film resistor 3 formed on the first insulating film 2, and a second insulating film 4 formed on the film resistor 3. The second insulating film 4 has a better heat conduction ability than the first insulating film 2. The area of the getter film 5 is smaller than the area of the second insulating film 4a. The total area of the getter structure 100 is designed according to the gettering requirement. For example, the surface of the getter structure 100 is a square as shown in Fig. 2a, and the length of one side is about 0.5-5 mm. Different from the embodiment 1, in the embodiment 2, the substrate 1 under the thermal sub 10 has a cavity 6. That is, the main part of the thermal sub 10 (i.e. the part carrying the getter film 5) is suspended above the cavity 6 and supported on the main surface of the substrate 1 around the cavity 6 through a connecting part, for example, a cantilever beam 7 (e.g. comprising 7a, 7b, 7c, 7d) which can be connected to the main surface la of the substrate 1. The cantilever beam 7 can have two branches or more than two branches. For example, in the embodiment, the cantilever beam 7 comprises four branches 7a, 7b, 7c, 7d. In this structure, the main part of the thermal sub 10 and the getter film 5 are separated from the rest of the area and connected only through the cantilever beam 7. In this way, the heat generated by the film resistor 3 only has a heat loss through the solid conduction of the cantilever beam 7. By properly designing the width, length and thickness of the cantilever beam, the heat loss through the solid conduction of the cantilever beam 7 can be made small enough. As a result, compared with the embodiment 1, the getter structure 100 of the embodiment 2 can more effectively conduct the heat generated by the thermal sub to the getter film 5, thereby improving the heating efficiency required to activate the getter film 5, which is effective for saving the heating energy and improving the maximum heating temperature. Figure 1 a square as shown in Fig. 2a, and the length of one side is about 0.5-5 mm. Different from the embodiment 1, in the embodiment 2, the substrate 1 under the thermal sub 10 has a cavity 6. That is, the main part of the thermal sub 10 (i.e. the part carrying the getter film 5) is suspended above the cavity 6 and supported on the main surface of the substrate 1 around the cavity 6 through a connecting part, for example, a cantilever beam 7 (e.g. comprising 7a, 7b, 7c, 7d) which can be connected to the main surface la of the substrate 1. The cantilever beam 7 can have two branches or more than two branches. For example, in the embodiment, the cantilever beam 7 comprises four branches 7a, 7b, 7c, 7d. In this structure, the main part of the thermal sub 10 and the getter film 5 are separated from the rest of the area and connected only through the cantilever beam 7. In this way, the heat generated by the film resistor 3 only has a heat loss through the solid conduction of the cantilever beam 7. By properly designing the width, length and thickness of the cantilever beam, the heat loss through the solid conduction of the cantilever beam 7 can be made small enough. As a result, compared with the embodiment 1, the getter structure 100 of the embodiment 2 can more effectively conduct the heat generated by the thermal sub to the getter film 5, thereby improving the heating efficiency required to activate the getter film 5, which is effective for saving the heating energy and improving the maximum heating temperature.

[0059] The substrate 1 has two corresponding main surfaces, i.e. a first main surface la and a second main surface lb. The substrate 1 can be the same as the substrate 1 of the embodiment 1.

[0060] The first insulating film 2 formed on the main surface la of the substrate 1 can be designed according to the performance requirement of the thermal sub. The first insulating film 2 can be the same as the first insulating film 2 of the embodiment 1.

[0061] The film resistor 3 formed on the first insulating film 2 can be designed according to the requirement of activating the getter film 5. The film resistor 3 can be the same as the film resistor 3 of the embodiment 1. For example, the film resistor 3 is a conductive film resistor as shown in Fig. 2b. Figure 2The thin film of c) is shown in plan view as a broken line. One end of the thin film resistor 3 is connected to the electrode 3a by a cantilever beam 7a, and the other end of the thin film resistor 3 is connected to the electrode 3b by a cantilever beam 7b. The electrodes 3a and 3b of the thin film resistor 3 are exposed through the window 4d formed in the second insulating thin film 4, so as to be connected to an external power source (not shown).

[0062] The second insulating thin film 4 formed on the thin film resistor 3 is designed in terms of material and thickness according to the thermal sub's performance requirements. The second insulating thin film 4 has the same function as the second insulating thin film 4 of Example 1. The second insulating thin film 4 can be the same as the second insulating thin film 4 of Example 1.

[0063] The first insulating thin film 2, the thin film resistor 3 formed on the first insulating thin film 2, and the second insulating thin film 4 formed on the thin film resistor 3 constitute the thermal sub 10.

[0064] The getter thin film 5 formed on the thermal sub 10 is made of a getter material. The getter thin film 5 is designed in terms of material, area, and thickness according to the type and amount of gas to be adsorbed, and other factors. The area of the getter thin film 5 is smaller than the area of the second insulating thin film 4a, so that the getter thin film 5 can be effectively activated through the second insulating thin film 4a. The getter thin film 5 can be the same as the getter thin film 5 of Example 1.

[0065] The thin film structure composed of the thermal sub 10 and the getter thin film 5 needs to be designed with proper consideration of the overall stress, so that the getter structure 100, especially the cantilever beam 7, will not be damaged by stress during manufacture and use. The cantilever beam 7 also needs to have sufficient strength to support the thin film structure composed of the thermal sub 10 and the getter thin film 5, so that it can be well suspended.

[0066] As described above, the present embodiment provides another small-sized getter structure with a built-in thermal sub. Such a structure has the following effects in addition to the effects of Example 1. That is, in this structure, the main part of the thermal sub 10 and the getter thin film 5 are connected to the rest of the area only through the cantilever beam 7, so that the loss of heat generated by the thin film resistor 3 due to solid conduction becomes small enough. As a result, the getter structure of the present embodiment can more effectively transfer the heat generated by the thermal sub to the getter thin film, and improve the heating efficiency required for activating the getter thin film, which is effective for saving heating energy and improving the maximum heatable temperature.

[0067] Example 3

[0068] Example 3 of the present application provides a getter structure. Such a getter structure has a built-in MEMS thermal sub. Figure 3 is a plan view of the present embodiment. In the present embodiment, in order to highlight the main idea of the present application, Figure 3The schematic diagram of the embodiment 2 only includes the most basic elements. The similar parts between the embodiment 2 and the above-mentioned embodiment 1 can be referred to the embodiment 1, and will not be described in detail here.

[0069] The feature of the embodiment 3 is that the getter structure 100 has two or more getter structure units composed of the hot sub 10 and the getter film 5 formed above it. For example, as shown in the figure, Figure 3 The getter structure 100 has two getter structure units. Each getter structure unit has a similar structure with the getter structure 100 of the embodiment 1. The getter film 5-1 of the first getter structure unit corresponds to a hot sub 10-1, and the getter film 5-2 of the second getter structure unit corresponds to a hot sub 10-2. The hot sub 10-1 and the hot sub 10-2 can be completely independent. However, in order to save the power input terminal, the hot sub 10-1 and the hot sub 10-2 can share an electrode 3c. Such a structure makes the hot sub 10-1 can be independently powered through the electrode 3-1a and the electrode 3c, and the hot sub 10-2 can be independently powered through the electrode 3-2a and the electrode 3c. That is, the getter film 5-1 and the getter film 5-2 can be independently activated by heating respectively.

[0070] The two or more getter structure units composed of the hot sub 10 and the getter film 5 formed above it are integrated on one substrate, so that the getter structure 100 is compact in volume, and the precious space of the micro vacuum cavity can be saved. In addition, because of the two or more thin film type getter structures with independent hot sub which can be independently activated, the independent thin film type getters can be activated at different time points, and the gas in the vacuum cavity can be effectively adsorbed multiple times as time increases. Compared with the structure with one getter structure unit, the service life of the MEMS device sealed together in the vacuum cavity can be further prolonged.

[0071] Embodiment 4

[0072] The embodiment 4 of the present application provides another getter structure. This getter structure has a MEMS hot sub. Figure 4 is a planar schematic diagram of the embodiment. In the embodiment, in order to highlight the main idea of the present application, Figure 4 The schematic diagram of the embodiment 2 only includes the most basic elements. The similar parts between the embodiment 4 and the above-mentioned embodiments 2, 3 can be referred to the embodiments 2, 3, and will not be described in detail here.

[0073] The feature of the embodiment 4 is that the getter structure 100 has two or more getter structure units composed of the hot sub 10 and the getter film 5 formed above it. For example, as shown in the figure, Figure 4As shown, the getter structure 100 has two getter structure units. Each getter structure unit has a similar structure as the getter structure 100 of embodiment 2. The getter film 5-1 of the first getter structure unit corresponds to a heating element 10-1, and the getter film 5-2 of the second getter structure unit corresponds to a heating element 10-2. The heating element 10-1 and the heating element 10-2 can be completely independent. However, in order to save the power input terminal, the heating element 10-1 and the heating element 10-2 can share an electrode 3c. Such a structure makes the heating element 10-1 be independently powered through the electrode 3-la and the electrode 3c, and the heating element 10-2 be independently powered through the electrode 3-2a and the electrode 3c. That is, the getter film 5-1 and the getter film 5-2 can be independently activated by heating respectively.

[0074] The getter structure of the present embodiment integrates the effects of embodiment 2 and embodiment 3, and can more effectively activate the independent thin film getter at different time points, thereby prolonging the service life of the MEMS device sealed together in the vacuum cavity.

[0075] Embodiment 5

[0076] The present embodiment 5 provides a manufacturing method of a getter structure. Figure 5 is a cross-sectional schematic view of the present embodiment. The getter structure Figure 1 described in embodiment 1 and Figure 3 described in embodiment 3. In the present embodiment, in order to highlight the main idea of the present application, Figure 5 the schematic view only includes the most basic elements. The structures, materials, etc. involved in the present embodiment 5 are the same as those in embodiment 1 and 3, and can be referred to embodiment 1 and 3, which will not be described in detail. For the sake of simplicity, the present embodiment 5 takes the getter structure 100 of embodiment 1 as an example to describe the manufacturing method.

[0077] The manufacturing method of the getter structure 100 provided by the present embodiment 5 includes: forming a heating element 10 on one main surface la of a substrate 1, and forming a getter film 5 on the heating element 10. The manufacturing method of the heating element 10 includes: forming a first insulating film 2 on one main surface la of a substrate 1, forming a conductive thin film resistor 3 on the first insulating film 2, and forming a second insulating film 4 on the thin film resistor 3. Further, the second insulating film 4 is processed to separate the second insulating film 4a covering the main part of the thin film resistor 3 from the second insulating film 4b in the remaining area. The manufacturing method will be described step by step as follows.

[0078] First, as shown in Figure 5As 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 can be the substrate 1 described in Embodiment 1. For simplicity and convenience, this embodiment uses a Si substrate, which is conventionally used in semiconductor processes, as an example for description.

[0079] Then, as Figure 5 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 1. For example, the first insulating film 2 is a silicon oxide film with a thickness of 0.3 micrometers, formed using conventional TEOS CVD (TEOS: Tetraethyl orthosilicate; CVD: Chemical Vapor Deposition) and associated processes.

[0080] Then, as Figure 5 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 a metal W with a thickness of 0.2 micrometers, formed using conventional magnetron sputtering and associated processes.

[0081] Then, as Figure 5 As shown in d), the conductive thin-film resistor 3 is processed to form Figure 1 Figure c shows a zigzag conductive thin-film resistor 3, with electrodes 3a and 3b at both ends. The conductive thin-film resistor 3 can be fabricated using conventional photolithography and metal etching processes, along with complementary techniques. For example, the metal etching process can utilize ion beam etching (IBE).

[0082] Then, as Figure 5 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 1. 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.

[0083] Then, as Figure 5 f) and Figure 1As shown in a), the second insulating film 4 is processed to form an isolation trench 4c and a window 4d. The processing of the second insulating film 4 can be performed using conventional photolithography and silicon nitride etching, along with associated processes. The isolation trench 4c is a channel formed on the second insulating film 4, which penetrates the upper and lower surfaces of the second insulating film 4 to reach the surface of the underlying first insulating film 2. The isolation trench 4c is formed around the periphery of the thin-film resistor 3, such that 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 through the isolation trench 4c. The window 4d is a window formed on the second insulating film 4, which penetrates the upper and lower surfaces of the second insulating film 4 to reach the surfaces of the underlying electrodes 3a and 3b.

[0084] Through such Figure 5 b) to Figure 5 The process shown in f) forms a heat source 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.

[0085] Then, as Figure 5 As shown in g), 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 1. 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 Zr-based non-evaporable getter material including ZrVFe, with a thickness of approximately 2 micrometers. The getter film 5 can be deposited on top of the second insulating film 4a using a magnetron sputtering method. In the getter film 5 deposition process, after completing... Figure 5 As shown in f), the processed substrate surface is covered with a metal mask (not shown). This metal mask is relative to... Figure 5 The getter film 5 shown in (g) has a partially open window, allowing it to be deposited onto the second insulating film 4a during magnetron sputtering. The advantage of using metal polishing is that it eliminates the need for etching the getter film 5, avoiding potential contamination during etching. Another advantage is the simplicity of the getter film 5 formation process, and the ability to reuse the metal mask, reducing manufacturing costs.

[0086] Obviously, using Figure 5 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 3.

[0087] As described above, this embodiment provides a method for manufacturing a getter structure, suitable for manufacturing the getter structures shown in Embodiments 1 and 3. 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.

[0088] Example 6

[0089] Embodiment 6 of this application provides another method for manufacturing a getter structure. Figure 6 This is a cross-sectional schematic diagram of this embodiment. The manufacturing method of this embodiment can be used to manufacture... Figure 2 The described embodiment 2 and Figure 4 The getter structure 100 of Example 4 is described. In this embodiment, in order to highlight the main idea of ​​this application, Figure 6 The schematic diagram only includes the most basic elements. The structures and materials involved in this Embodiment 6 are the same as those in Embodiments 2 and 4, and will not be described in detail here. For simplicity, the parts of this Embodiment 6 that are common to Embodiment 5 will not be described in detail here. For simplicity, this Embodiment 6 uses the getter structure 100 of Embodiment 2 as an example to describe the manufacturing method.

[0090] The manufacturing method of the getter structure 100 provided in this embodiment 6 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.

[0091] First, such as Figure 6 As 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.

[0092] Then, as Figure 6 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 and associated processes.

[0093] Then, as Figure 6 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 2. 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.

[0094] Then, as Figure 6 As shown in d), the conductive thin-film resistor 3 is processed to form Figure 2 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 methods.

[0095] Then, as Figure 6 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, which is grown using conventional PECVD.

[0096] Then, as Figure 6 f) and Figure 2 As 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.

[0097] Then, as Figure 6 g) and Figure 2As 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 or TMAH.

[0098] Through such Figure 6 b) to Figure 6 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.

[0099] Then, as Figure 6 h) and Figure 2 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.

[0100] Obviously, using Figure 6 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 2, but also to manufacture the multiple-unit getter structure 5 shown in Example 4.

[0101] As described above, this embodiment provides another method for manufacturing a getter structure, suitable for manufacturing the getter structures shown in Embodiments 2 and 4. 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.

[0102] Example 7

[0103] Embodiment 7 of this application provides a vacuum packaging structure for a MEMS device. Figure 7 This is a cross-sectional schematic diagram of this embodiment. In this embodiment, in order to highlight the main idea of ​​this application, Figure 7The schematic diagram only includes the most basic elements.

[0104] As Figure 7 shown in FIG. 1, the vacuum packaging structure 200 of the MEMS device of the embodiments of the present application includes a vacuum packaging shell 30 (including 30a and 30b), conductive terminals 32 (including 32a and 32b) for communicating between the inside and outside of the vacuum packaging shell 30b, a MEMS device 20 packaged inside the vacuum packaging shell 30, and a getter structure 100. The electrodes (not shown) of the getter structure 100 are in electrical communication with the conductive terminals 32b through wires 31b. A vacuum cavity 40 is formed inside the vacuum packaging shell 30.

[0105] The vacuum packaging shell 30 is composed of a shell 30a and a shell 30b, and conductive terminals 32 (including 32a and 32b) for communicating between the inside and outside of the vacuum packaging shell 30b. The vacuum packaging shell 30 is a standard component used for vacuum packaging of semiconductor devices and MEMS devices, and a vacuum cavity 40 is formed inside after packaging. The initial vacuum degree of the vacuum cavity 40 meets the vacuum degree required for normal operation of the MEMS device 20. The conductive terminals 32a are a plurality of conductive terminals, each in electrical communication with a respective electrode of the MEMS device 20. The conductive terminals 32b are a plurality of conductive terminals, each in electrical communication with a respective electrode of the getter structure 100.

[0106] The MEMS device 20 is a MEMS device that needs to operate in a certain vacuum atmosphere. For example, the MEMS device 20 can be one or more of the following MEMS devices: a MEMS oscillator, a MEMS pressure sensor, a MEMS resonant filter, a MEMS inertial sensor (MEMS gyroscope and MEMS accelerometer, etc.), a MEMS infrared imaging device, etc. Each electrode of the MEMS device 20 is in electrical communication with a different conductive terminal 32a through a different wire 31a.

[0107] The getter structure 100 is one of the getter structures 100 described in Embodiments 1-4. The getter structure 100 can be one or a plurality. Each getter structure 100 can include a single getter structure unit as shown in Embodiments 1 and 3, or a plurality of getter structure units as shown in Embodiments 2 and 4. Each electrode of the getter structure 100 is in electrical communication with a different conductive terminal 32b through a different wire 31b.

[0108] The at least one getter structure unit of the getter structure 100 can be activated immediately after the packaging of the vacuum packaging structure 200 is completed, to absorb the gas remaining in the vacuum cavity 40, so that the vacuum degree of the vacuum cavity 40 meets the working requirement of the MEMS device 20. The at least one getter structure unit of the getter structure 100 can be activated after a certain period of time after the packaging of the vacuum packaging structure 200 is completed, to absorb the gas generated in or entering into the vacuum cavity 40, so that the vacuum degree of the deteriorated vacuum cavity 40 meets the working requirement of the MEMS device 20 again. The activation of the getter film 5 can be achieved by delivering electric energy to the heat sub 10 through the conductive terminal 32b, so as to increase the temperature of the getter film 5 to its activation temperature. The vacuum packaging of the plurality of getter structure units and the MEMS device 20 at the same time can activate the getter film 5 in time when needed. Thus, compared with the case that the getter can be activated only once, the embodiment can make the MEMS device 20 be in a more ideal vacuum environment for a longer time. This means that not only the performance stability and reliability of the MEMS device can be improved, but also the service life of the MEMS device and the entire component of the vacuum packaging structure containing the MEMS device can be extended several times, so as to reduce the use cost. In addition, the getter film 5 of each getter structure unit can be activated several times because it is provided with the heat sub 10. Although the getter effect of the getter film 5 will decrease after the second activation, it can still play a role in improving the vacuum degree inside the vacuum cavity 40.

[0109] As described above, the packaging structure of the MEMS device provided by the embodiment can activate the getter structure at any time when needed due to the inclusion of the micro heat sub, so as to improve the performance stability and reliability of the MEMS device, and can also prolong the service life of the MEMS device and reduce the use cost. Because the heat sub and the getter film are integrated and have a small volume, the space of the packaging structure of the MEMS device can be saved.

[0110] The application is described above in conjunction with specific embodiments, but those skilled in the art should understand that these descriptions are exemplary and are not a limitation on the scope of protection of the application. Those skilled in the art can make various modifications and changes to the application according to the spirit and principles of the application, and these modifications and changes are also within the scope of the application.

Claims

1. A thin-film getter structure with a microheater, comprising: substrate; A heat source formed on one side of a main surface of the substrate; as well as A getter film formed on the surface of the heat exchanger The thermal electrons include: First insulating film; The thin-film resistance formed on the upper surface of the first insulating film; and A second insulating film covering the thin-film resistor. The two ends of the thin-film resistor are electrodes exposed from the second insulating film. The thermal conductivity of the second insulating film is higher than that of the first insulating film. The first insulating film is silicon oxide, and the second insulating film is silicon nitride. in, The thin-film getter structure includes two heat sinks and two getter films disposed on one side of the main surface of the same substrate, with each getter film disposed on the upper surface of the corresponding heat sink. The two heat sources share a single electrode.

2. The thin-film getter structure as described in claim 1, wherein, The second insulating film includes a first portion and a second portion, which are separated from each other by an insulating groove. The first portion covers the area of ​​the thin-film resistor.

3. The thin-film getter structure as described in claim 2, 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.

4. A vacuum packaging structure for a microelectromechanical system (MEMS) device, comprising: A vacuum-sealed housing, wherein the interior of the vacuum-sealed housing is formed as a vacuum cavity; Microelectromechanical systems (MEMS) devices encapsulated inside the vacuum-sealed housing; 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 The thin-film getter structure as described in any one of claims 1 to 3 is encapsulated inside the vacuum-sealed housing. The electrodes of the thin-film resistor in the thin-film getter structure are electrically connected to the conductive terminal.

5. A method for manufacturing a thin-film getter structure with a microheater, comprising: A thermal element is formed on one of the main surfaces of the substrate; as well as A getter film is formed on the surface of the heat source; The steps for forming the thermal electrons include: A first insulating film is formed on one main surface of the substrate; A thin-film resistor is formed on the upper surface of the first insulating film; and A second insulating film is formed to cover the thin film resistor. The two ends of the thin-film resistor are formed as electrodes exposed from the second insulating film. The thermal conductivity of the second insulating film is higher than that of the first insulating film. The first insulating film is silicon oxide, and the second insulating film is silicon nitride. in, The thin-film getter structure includes two heat sinks and two getter films disposed on one side of the main surface of the same substrate, with each getter film disposed on the upper surface of the corresponding heat sink. The two heat sources share a single electrode.

6. The manufacturing method as described in claim 5, wherein, The steps for forming the heat source further include: An isolation groove is formed in the second insulating film, the isolation groove separating the first and second portions of the second insulating film from each other. The first part covers the region of the thin-film resistor.

7. The manufacturing method as described in 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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