Method for manufacturing getter film structure

Abstract

The application provides a getter film structure manufacturing method, comprising the following steps: forming a first getter thin layer above one main surface of a substrate, forming a plurality of grooves arranged at intervals in the first getter thin layer to form a patterned getter thin layer; filling a patterned sacrificial layer in the grooves, and forming a second getter thin layer on the patterned sacrificial layer and the patterned getter thin layer; removing the patterned sacrificial layer to form apertures in the in-plane direction of the patterned getter thin layer, and the apertures have openings on the side surface of the patterned getter thin layer. The application forms a transverse channel of the getter film through the apertures in the in-plane direction of the film, which can increase the specific surface area of the getter film, greatly improve the gettering capacity and speed, and ensure the use property of the getter film structure. Compared with the common getter film, the application can achieve the same gettering effect with less getter, thereby reducing the overall cost of the device.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of MEMS design and manufacturing, and particularly relates to a manufacturing method of a getter film structure. BACKGROUND

[0002] It is known that some semiconductor devices, particularly some micro electro mechanical systems (MEMS) devices, need to be packaged to work in a vacuum environment. For example, MEMS acceleration sensors, gyroscopes, vacuum gauges, etc. with high-speed moving (displacement or vibration or rotation) parts need to be packaged in a relatively stable vacuum environment. For another example, MEMS pressure sensors need to have a vacuum cavity, and the vacuum cavity needs to have a relatively high vacuum, and the vacuum degree needs to be kept stable. In addition, some infrared sensors also need to be packaged in a vacuum cavity with a relatively high vacuum.

[0003] On the one hand, it is challenging to achieve a 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, and activate the getter during the packaging or after the packaging is completed, to absorb the residual gas in the vacuum cavity and achieve a high vacuum required for the operation of the device. Getter, also known as gas absorber, in the field of vacuum technology, refers to a material that can effectively absorb and fix some or certain gas molecules. 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 will continue to diffuse into the material, so as to achieve the purpose of removing a large amount of active gas. Generally speaking, the adsorption effect of the getter is better and faster on the surface, so the larger the surface area of the getter, the better the adsorption performance (i.e. the more gas can be adsorbed, and the faster the adsorption rate). This is also the reason why the getter is made into a porous material. The thin film type getter structure has the advantages of small space occupation, easy compatibility with device process, easy wafer level packaging, and suitability for mass production.

[0004] However, the specific surface area of the existing getter is small, which makes it difficult to improve the getter performance. SUMMARY

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a manufacturing method of a getter film structure, which solves the problem that the specific surface area of the existing getter is small, which makes it difficult to improve the getter performance.

[0006] To achieve the above object and other related objects, the present application provides a method for manufacturing a getter film structure, which comprises the following steps: providing a substrate, forming a first getter thin layer above one main surface of the substrate, forming a plurality of grooves arranged at intervals in the first getter thin layer to form a patterned getter thin layer, filling a patterned sacrificial layer in the grooves of the patterned getter thin layer, and forming a second getter thin layer on the patterned sacrificial layer and the patterned getter thin layer, and removing the patterned sacrificial layer to form apertures in the in-plane direction of the patterned getter thin layer, the apertures having openings on the side surface of the patterned getter thin layer.

[0007] Optionally, the method further comprises the following steps: forming a first getter thin layer above the substrate, forming a plurality of grooves arranged at intervals in the first getter thin layer to form a patterned getter thin layer, filling a first patterned sacrificial layer in the grooves of the patterned getter thin layer, repeating the above steps to form N patterned getter thin layers and N-1 patterned sacrificial layers, wherein N≥2, and no patterned sacrificial layer is formed on the topmost patterned getter thin layer, and removing the N-1 patterned sacrificial layers to form apertures in the in-plane direction of each of the patterned getter thin layers, the apertures having openings on the side surface of the patterned getter thin layer.

[0008] Optionally, the apertures in the in-plane direction of the patterned getter thin layer penetrate through both sides of the patterned getter thin layer to form openings on both sides of the patterned getter thin layer.

[0009] Optionally, the projections of the apertures in the adjacent two patterned getter thin layers on the substrate intersect with each other.

[0010] Optionally, the projections of the apertures in the adjacent two patterned getter thin layers on the substrate perpendicularly intersect with each other.

[0011] Optionally, the length of the apertures in the in-plane direction of the patterned getter thin layer is not less than the thickness of the patterned getter thin layer.

[0012] Optionally, the width of the apertures in the in-plane direction of the patterned getter thin layer is not less than 50 nm.

[0013] Optionally, before the first getter thin layer is formed, the method further comprises the following step: forming a bottom getter thin layer above one main surface of the substrate.

[0014] Optionally, the getter thin layer is formed by a sputtering method.

[0015] Optionally, the method for removing the patterned sacrificial layer comprises one of a liquid solvent dissolving method and a gas plasma etching method.

[0016] Optionally, the patterned sacrificial layer comprises one of a pattern formed by photoresist and a pattern formed by polyimide.

[0017] Optionally, the patterned sacrificial layer comprises a pattern formed by a compound of silicon.

[0018] Optionally, the getter thin layer comprises one of Zr-based non-evaporable getter and Ti-based non-evaporable getter.

[0019] Optionally, the getter thin layer has a thickness of 100 nm to 1 μm.

[0020] As described above, the method for manufacturing the getter thin film structure of the present application has the following beneficial effects:

[0021] The present application provides a getter thin film structure, which forms transverse channels of the getter thin film through voids in the in-plane direction, so that the specific surface area of the getter thin film can be increased, and the gettering capacity and speed can be greatly improved. On the other hand, the getter thin film structure of the present application can have sufficient mechanical strength, and the usability is guaranteed. On the other hand, compared with ordinary getter thin film, the present application can use less getter to achieve the same gettering effect, thereby reducing the overall cost of the device. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings, which are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this application, illustrate embodiments of the present application and together with the description serve to explain the principles of the present application. It is readily understood that the drawings are merely illustrative of some embodiments of the present application.

[0023] Figure 1 FIG. 1 shows a schematic diagram of the three-dimensional structure of the getter thin film structure prepared in the embodiment of the present application, Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 FIG. 2 shows a schematic diagram of the cross-sectional structure at A-A' in the corresponding step of the method for manufacturing the getter thin film structure in the embodiment of the present application, Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 FIG. 3 shows a schematic diagram of the cross-sectional structure at B-B' in the corresponding step of the method for manufacturing the getter thin film structure in the embodiment of the present application.

[0024] ELEMENT REFERENCE

[0025] 10 substrate

[0026] 20 getter thin film structure

[0027] 21 first layer of getter thin layer

[0028] 21' First layer of patterned getter thin layer

[0029] 31 First layer of graphic sacrifice layer

[0030] 22 Second getter layer

[0031] 22' Second layer graphic getter thin layer

[0032] 32 Second layer of graphic sacrifice layer

[0033] 23 Third getter layer

[0034] 23' Third layer graphic getter thin layer

[0035] 33 Third layer of graphic sacrifice layer

[0036] 24. Fourth layer of getter thin layer

[0037] 24' Fourth layer graphic getter thin layer

[0038] 34 Fourth layer of graphic sacrifice layer

[0039] 25. Fifth layer of getter film

[0040] 25' Fifth layer graphic getter thin layer

[0041] 41 Pores Detailed Implementation

[0042] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0043] In the detailed description of embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0044] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for devices in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it may be the only layer between the two layers, or there may be one or more layers in between.

[0045] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0046] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0047] Sputtering is a common technique for forming getter thin film structures. Sputtered getter thin film structures easily form continuous pores along the thickness direction, but it is difficult to form continuous pores in the in-plane direction. Furthermore, when the getter film thickness reaches a certain level, it becomes difficult to create pores connecting the film surface to the bottom layer, and the pores inside the film also become smaller. This not only limits the surface area of ​​the film but also slows down the adsorption rate. Therefore, once the film thickness reaches a certain level, the effect of increasing the getter adsorption performance by increasing the film thickness decreases. Moreover, getters are generally expensive, and increasing the getter film thickness means increasing the cost of the entire encapsulated device. On the other hand, reducing the density of the getter film can increase porosity, thereby increasing the surface area of ​​the getter film. However, excessively loose density will degrade the mechanical properties of the film, making it prone to breakage and detachment, thus affecting usability.

[0048] like Figures 1-9As shown, the present invention provides a method for manufacturing a getter film structure, the method comprising the steps of: providing a substrate, forming a first getter film layer above a main surface of the substrate, forming a plurality of trenches spaced apart in the first getter film layer to form a patterned getter film layer; filling the trenches with a patterned sacrificial layer, and forming a second getter film layer on the patterned sacrificial layer and the patterned getter film; removing the patterned sacrificial layer to form pores 41 in the in-plane direction of the patterned getter film layer, the pores 41 having openings on the side surface of the patterned getter film layer.

[0049] In one embodiment, the manufacturing method may include the following steps: 1) forming a first getter layer over the substrate, and forming a plurality of trenches spaced apart in the getter layer to form a patterned getter layer; 2) filling the trenches of the patterned getter layer with a first patterned sacrificial layer; 3) repeating the above steps to form N patterned getter layers and N-1 patterned sacrificial layers, wherein N≥2, and no patterned sacrificial layer is required to be formed on the topmost patterned getter layer; 4) removing N-1 patterned sacrificial layers to form a pore 41 in the in-plane direction of each patterned getter layer, the pore having an opening on the side of the patterned getter layer.

[0050] In one embodiment, the substrate may be a silicon substrate, a glass substrate, a quartz substrate, or a metal cover plate for MEMS packaging, etc.

[0051] In one embodiment, the pores extend through both sides of the patterned getter layer in the in-plane direction to form openings on both sides of the patterned getter layer, thereby forming a transverse channel in the getter layer. This transverse channel has a through-hole structure, which can effectively increase the gas flow velocity, thereby increasing the getter velocity of the getter layer.

[0052] In one embodiment, the projections of pores in two adjacent patterned getter layers onto the substrate intersect. For example, the intersection angle of the projections of pores in two adjacent patterned getter layers onto the substrate can be 30 degrees, 45 degrees, 60 degrees, 90 degrees, etc. In a specific implementation, the projections of pores in two adjacent patterned getter layers onto the substrate intersect perpendicularly.

[0053] In one embodiment, the length of the pores in the in-plane direction of the patterned getter layer is not less than the thickness of the patterned getter layer, thereby ensuring at least the getter capacity and getter speed of the patterned getter layer.

[0054] In one embodiment, the width of the pores in the in-plane direction of the patterned getter thin layer is not less than 50 nm. For example, the width of the pores in the in-plane direction of the patterned getter thin layer can be 80 nm, 100 nm, 150 nm, etc. This width range can ensure the specific surface area of ​​the patterned getter thin layer on the one hand, and the mechanical strength of the patterned getter thin layer on the other hand.

[0055] In one embodiment, before the first getter layer is formed, the step further includes: forming a bottom getter layer above a main surface of the substrate. The bottom getter layer may be patterned or may not be patterned but may absorb air through pores above it (located in the pores of the first getter layer) to improve the air absorption capacity of the getter film structure while making better use of space.

[0056] In one embodiment, the getter layer is formed by sputtering or vacuum evaporation.

[0057] In one embodiment, the method for removing the patterned sacrificial layer includes one of a liquid solvent dissolution method and a gas plasma etching method.

[0058] In one embodiment, the patterned sacrificial layer comprises either a pattern formed by photoresist or a pattern formed by polyimide.

[0059] In one embodiment, the patterned sacrificial layer comprises a pattern formed of a silicon compound, the silicon compound having a selectivity ratio with the getter layer in the same etching process, such that the selectivity ratio is, for example, greater than 50:1.

[0060] In one embodiment, the material of the getter thin layer can be a Zr-based non-evaporable getter, such as Zr-V-Fe, Zr-Al, Zr-Mn-Fe, etc., or a Ti-based non-evaporable getter, such as Ti-Fe-V-Mn, Ti-Mo, Ti-Zr-Ni, etc.

[0061] In one embodiment, the thickness of the getter layer is 100 nm to 1 μm, and the thickness of the getter layer can be, for example, 200 nm, 500 nm, 800 nm, etc.

[0062] like Figures 1-8 As shown, where, Figure 1 The diagram shown is a three-dimensional structural schematic of the getter film structure 20 prepared in this embodiment. Figure 2 , 3 Figures 4 and 5 show the cross-sectional structural diagrams at point A-A' in the corresponding steps. Figure 6 , 7Figure 8 shows a schematic diagram of the cross-sectional structure at point B-B' in the corresponding step. The preparation process of a 5-layer getter film structure 20 is described in detail below.

[0063] like Figure 2 As shown, step 1) is performed first, providing a substrate 10. At room temperature, a first getter layer 21 is sputtered and deposited on the substrate 10. The thickness of this getter layer can be 100 nm to 1 μm. The material of the getter layer is a Zr-based non-evaporable getter or a Ti-based non-evaporable getter. Alternatively, before preparing the first getter layer 21, a bottom getter layer (not shown) can be formed above one of the main surfaces of the substrate 10.

[0064] like Figure 3 As shown, step 2) is then performed to pattern the first getter layer 21 to form a patterned first getter layer 21', thereby forming the desired trench pattern on the surface of the first getter layer 21. The trenches can either completely penetrate the first patterned getter layer 21' in the thickness direction, or they can not penetrate the first patterned getter layer 21' in the thickness direction, leaving a portion of the first getter layer 21 at the bottom of the trench. The width of the trench can be 50 nm to 1 μm, and the number of trenches is not less than two, and can be customized according to actual needs. The patterning process can employ either an etching method or a hard mask method. The etching method involves spin-coating photoresist onto the first getter layer 21, followed by exposure, development, and etching to form the desired trenches on the first getter layer 21, and finally removing the photoresist. The hard masking method uses a patterned metal mask. First, a metal layer is deposited on the surface of the first getter layer 21 as a mask. Then, the metal mask is patterned by etching to form a patterned metal mask. After that, the getter layer is etched to form a trench pattern in the getter film. Finally, the metal mask is removed.

[0065] like Figure 4 As shown, step 3) is then performed, where photoresist is filled into the trench position of the first getter layer 21 as the first pattern sacrificial layer 31. The photoresist filling method can be spin coating, etc.

[0066] like Figure 5 As shown, step 4) is then performed, where a second getter layer 22 with a thickness of 100 nm to 1 μm is sputtered and deposited on the first patterned getter layer 21'.

[0067] like Figure 6As shown, then step 5) is performed to pattern the second getter layer 22 to form a second patterned getter layer 22'. The pattern of the second patterned getter layer 22' is perpendicular to the pattern of the first patterned getter layer 21'. If there are a total of two getter layers (N=2), the sacrificial layer can be removed after this step. However, in this example, there are a total of 5 getter layers, so the following steps are required.

[0068] like Figure 7 As shown, step 6) is then performed. After patterning the second getter layer 22, photoresist is filled into the trenches of the second getter layer 22 as the second patterning sacrificial layer 32.

[0069] like Figure 8 As shown, step 7) is then performed, repeating steps 1) to 6) until a third patterned getter layer 23' and a third patterned sacrificial layer 33 are formed based on the third getter layer 23; a fourth patterned getter layer 24' and a fourth patterned sacrificial layer 34 are formed based on the fourth getter layer 24; and a fifth patterned getter layer 25' is formed based on the fifth getter layer 25. The trenches of the fifth patterned getter layer 25' do not need to be filled with a patterned sacrificial layer. The pattern of each patterned getter layer is perpendicular to the pattern of the adjacent getter layers, thereby effectively improving the mechanical strength of the final prepared getter film structure 20.

[0070] like Figure 9 As shown, in step 8), after depositing and patterning the five getter layers, the wafer is immersed in an organic cleaning tank to remove the patterning sacrificial layer using a wet process, ultimately achieving... Figure 1 The getter film structure 20 shown has pores 41 (lateral channels). In this embodiment, the projections of the pores 41 of two adjacent getter films onto the substrate 10 are perpendicular. The getter film structure 20 prepared using this method can achieve the adsorption of a larger amount of gas, and the gas adsorption rate is faster than that of normal film getters.

[0071] As described above, the method for manufacturing the getter film structure 20 of the present invention has the following beneficial effects:

[0072] This invention provides a getter film structure 20, which forms lateral channels in the getter film through in-plane voids, thereby increasing the specific surface area of ​​the getter film and significantly improving its getter capacity and speed. Furthermore, the getter film structure 20 of this invention possesses sufficient mechanical strength, ensuring usability. Moreover, compared to ordinary getter films, this invention can achieve the same getter effect with less getter, thus reducing the overall cost of the device.

[0073] Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0074] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for manufacturing a getter film structure, characterized in that, The manufacturing method includes the following steps: A substrate is provided, and a first getter layer is formed over a main surface of the substrate, wherein a plurality of trenches are formed in the first getter layer at intervals to form a patterned getter layer. A patterned sacrificial layer is filled into the trench, and a top layer of getter is formed on the patterned sacrificial layer and the patterned getter layer; The patterned sacrificial layer is removed to form pores in the in-plane direction of the patterned getter layer, the pores having openings on the side surface of the patterned getter layer.

2. The method for manufacturing the getter film structure according to claim 1, characterized in that, include: A first getter layer is formed on the substrate, and a plurality of grooves are formed in the getter layer at intervals to form a patterned getter layer. A first patterned sacrificial layer is filled within the grooves of the patterned getter layer; Repeat the above steps to form N patterned getter layers and N-1 patterned sacrificial layers, where N≥2, and a patterned sacrificial layer does not need to be formed on the top getter layer; N-1 of the patterned sacrificial layers are removed to form pores in the in-plane direction of each of the patterned getter layers, the pores having openings on the side surfaces of the patterned getter layers.

3. The method for manufacturing the getter film structure according to claim 2, characterized in that, The pores extend in the in-plane direction through both sides of the patterned getter layer to form openings on both sides of the patterned getter layer.

4. The method for manufacturing the getter film structure according to claim 2, characterized in that, The projections of pores in two adjacent patterned getter layers onto the substrate intersect.

5. The method for manufacturing the getter film structure according to claim 4, characterized in that, The projections of the pores in two adjacent patterned getter layers onto the substrate are perpendicular.

6. The method for manufacturing the getter film structure according to claim 1, characterized in that, The length of the pores in the in-plane direction of the patterned getter layer is not less than the thickness of the patterned getter layer.

7. The method for manufacturing the getter film structure according to claim 1, characterized in that, The width of the pores in the in-plane direction of the patterned getter thin layer is not less than 50 nm.

8. The method for manufacturing the getter film structure according to claim 1, characterized in that, Before the first getter layer is formed, the method further includes the step of forming a bottom getter layer over a main surface of the substrate.

9. The method for manufacturing the getter film structure according to claim 1, characterized in that, The getter layer is formed by sputtering.

10. The method for manufacturing the getter film structure according to claim 1, characterized in that, The method for removing the patterned sacrificial layer includes one of the following: liquid solvent dissolution method and gas plasma etching method.

11. The method for manufacturing the getter film structure according to claim 1, characterized in that, The patterned sacrificial layer includes either a pattern formed by photoresist or a pattern formed by polyimide.

12. The method for manufacturing the getter film structure according to claim 1, characterized in that, The patterned sacrificial layer comprises a pattern formed from silicon compounds.

13. The method for manufacturing the getter film structure according to claim 1, characterized in that, The material of the getter thin layer includes one of Zr-based non-evaporable getters and Ti-based non-evaporable getters.

14. The method for manufacturing the getter film structure according to claim 1, characterized in that, The thickness of the getter layer is 100 nm to 1 μm.

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