CN116022727A - Method for manufacturing getter film structure - Google Patents

Abstract

The invention provides a method for manufacturing a getter film structure, which comprises the following steps: forming a first getter thin layer over one main surface of the substrate, forming a plurality of grooves in the first getter thin layer which are arranged at intervals, so as to form a pattern getter thin layer; filling a pattern sacrificial layer in the groove, and forming a second getter thin layer on the pattern sacrificial layer and the pattern getter thin film; the pattern sacrificial layer is removed to form pores in an in-plane direction of the pattern getter thin layer, the pores having openings at sides of the pattern getter thin layer. The invention can increase the specific surface area of the getter film by forming the transverse channels of the getter film in the gaps in the film surface direction, so that the gettering capability and speed of the getter film are greatly improved. The getter film structure can have sufficient mechanical strength and workability is ensured. Compared with the common getter film, the invention can achieve the same gettering effect by using less getters, thereby reducing the overall cost of the device.

Description

Getter film structure manufacturing method

technical field

The invention belongs to the field of MEMS design and manufacture, in particular to a method for manufacturing a getter film structure.

Background technique

As we all know, some semiconductor devices, especially some MEMS (Micro ElectroMechanical Systems) 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) components need to package the moving parts in a relatively stable vacuum environment. For another example, a MEMS pressure sensor with a vacuum cavity is required, and a high vacuum inside the vacuum cavity is also required, and its vacuum degree needs to be kept stable. In addition, some infrared sensors also need to package the device in a vacuum cavity with a high vacuum.

On the one hand, achieving higher vacuum packaging is inherently challenging. Because, during the packaging process, there is often some residual gas trapped in the vacuum chamber. For this reason, it is often necessary to seal the getter in the vacuum chamber, activate the getter at the same time of packaging, or activate the getter after the packaging is completed, and absorb the residual gas in the vacuum chamber to meet the needs of the device. higher vacuum. Getter, also called getter, in the field of vacuum technology, refers to a material that can effectively absorb and fix some or a certain gas molecule. The getter material is usually a porous structure. When the active gas molecules collide with the surface of the clean getter material, some gas molecules are adsorbed, which is the physical adsorption of the getter material; some gas molecules will chemically react with the getter material to form a stable The solid solution, which is the chemisorption of the getter material. And the gas molecules will continue to diffuse into the material, so as to achieve the purpose of extracting a large amount of active gas. Generally speaking, the adsorption effect of the getter on the surface is better and the adsorption is faster. Therefore, the larger the surface area of the getter, the better the adsorption performance (that is, the larger the amount of gas that can be adsorbed, the faster the adsorption rate). This is why the getter should be made of a porous material. The film-type getter structure has the advantages of small footprint, easy compatibility with device technology, convenient wafer-level packaging, and suitable for mass production.

However, the small specific surface area of existing getters makes it difficult to improve their getter performance.

Contents of the invention

In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for manufacturing a getter thin film structure, which is used to solve the problem that the getter in the prior art has a small specific surface area and it is difficult to improve its getter performance. The problem.

In order to achieve the above object and other related objects, the present invention provides a method for manufacturing a getter thin film structure. The manufacturing method includes the steps of: providing a substrate, and forming a first getter thin film on one main surface of the substrate. Layer, forming a plurality of grooves arranged at intervals in the first getter thin layer to form a patterned getter thin layer; filling the patterned sacrificial layer in the grooves, and filling the patterned sacrificial layer and forming a second getter thin layer on the graphic getter film; removing the graphic sacrificial layer to form pores in the in-plane direction of the graphic getter thin layer, and the pores getter in the graphic The side of the agent thin layer has openings.

Optionally, the manufacturing method includes: forming a first getter thin layer on the substrate, and forming a plurality of grooves arranged at intervals in the getter thin layer to form a graphic getter Thin layer; fill the first graphic sacrificial layer in the groove of the graphic getter thin layer; repeat the above steps to form N graphic getter thin layers and N-1 graphic sacrificial layers, where N≥ 2. There is no need to form a patterned sacrificial layer on the topmost patterned getter thin layer; remove N-1 patterned sacrificial layers to form pores in the in-plane direction of each patterned getter thin layer, so The pores have openings on the sides of the graphic getter sheet.

Optionally, the pores penetrate through both sides of the graphic getter thin layer in the in-plane direction of the graphic getter thin layer to form openings on both sides of the graphic getter thin layer.

Optionally, the projections of the pores in two adjacent graphic getter thin layers on the substrate have intersections.

Optionally, projections of pores in two adjacent graphic getter thin layers on the substrate intersect vertically.

Optionally, the length of the pores in the in-plane direction of the graphic getter thin layer is not less than the thickness of the graphic getter thin layer.

Optionally, the width of the pores in the in-plane direction of the graphic getter thin layer is not less than 50 nm.

Optionally, before the formation of the first getter thin layer, a further step is included: forming a bottom getter thin layer on one main surface of the substrate.

Optionally, the getter thin layer is formed by sputtering.

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

Optionally, the pattern sacrificial layer includes one of patterns formed by photoresist and patterns formed by polyimide.

Optionally, the patterned sacrificial layer includes patterns formed by silicon compounds.

Optionally, the material of the getter thin layer includes one of a Zr-based non-evaporable getter and a Ti-based non-evaporable getter.

Optionally, the thickness of the getter thin layer is 100 nm˜1 μm.

As mentioned above, the manufacturing method of the getter film structure of the present invention has the following beneficial effects:

The invention provides a getter film structure, through which the transverse channels of the getter film are formed through the gaps in the in-plane direction, the specific surface area of the getter film can be increased, and the air-breathing capacity and speed of the getter film can be greatly improved. On the other hand, the getter thin film structure of the present invention can have sufficient mechanical strength, and the usability is guaranteed. On the other hand, compared with the ordinary getter film, the present invention can use less getter to achieve the same getter effect, thereby reducing the overall cost of the device.

Description of drawings

The included drawings are used to provide a further understanding of the embodiments of the present application, which constitute a part of the specification, are used to illustrate the implementation of the present application, and explain the principle of the present application together with the text description. Apparently, the drawings in the following description are only some embodiments of the present application.

Figure 1 shows a schematic diagram of the three-dimensional structure of the getter film structure prepared in the embodiment of the present invention, and Figure 2, Figure 3, Figure 4, and Figure 5 show the corresponding steps in the manufacturing method of the getter film structure in the embodiment of the present invention 6, 7, 8, and 9 show the schematic cross-sectional structure at BB' in the corresponding steps of the manufacturing method of the getter film structure according to the embodiment of the present invention.

Component designation description

10 Substrate

20 Getter Thin Film Structure

21 The first thin layer of getter

21' first thin layer of graphic getter

31 The first graphic sacrificial layer

22 second thin layer of getter

22' second thin layer of graphic getter

32 The second graphic sacrificial layer

23 The third thin layer of getter

23' third graphic getter thin layer

33 The third graphic sacrificial layer

24 The fourth thin layer of getter

24' thin layer of fourth graphic getter

34 The fourth layer graphic sacrificial layer

25 The fifth thin layer of getter

25' fifth layer graphic getter thin layer

41 porosity

Detailed ways

Embodiments of the present invention are described below through specific examples, and 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 implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention.

For example, when describing the embodiments of the present invention in detail, for the convenience of explanation, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic diagram is only an example, which should not limit the protection scope of the present invention. In addition, the three-dimensional space dimensions of length, width and depth should be included in actual production.

For the convenience of description, spatial relation terms such as "below", "below", "below", "below", "above", "on" etc. may be used herein to describe an element or element shown in the drawings. The relationship of a feature to other components or features. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

In the context of this application, structures described as having a first feature "on top of" a second feature may include embodiments where the first and second features are formed in direct contact, as well as additional features formed between the first and second features. Embodiments between the second feature such that the first and second features may not be in direct contact.

It should be noted that the diagrams provided in this embodiment are only schematically illustrating the basic idea of the present invention, so that only the components related to the present invention are shown in the diagrams rather than the number, shape and Dimensional drawing, the type, quantity and proportion of each component can be changed arbitrarily during actual implementation, and the component layout type may also be more complicated.

Sputtering is a common technique for forming getter thin film structures. The getter film structure formed by sputtering is easy to form continuous pores in the film thickness direction, but it is difficult to form continuous pores in the film in-plane direction. However, when the thickness of the getter film reaches a certain level, it will become difficult to realize the pores connected from the surface of the film to the bottom layer of the film, and the pores will become smaller inside the film. In this way, not only the surface area of the film is limited, but also the speed of adsorption will be slowed down. Therefore, when the film thickness reaches a certain level, the effect of increasing the adsorption performance of the getter by increasing the film thickness decreases. Moreover, the cost of the getter is generally high, and increasing the thickness of the getter film means increasing the cost of the entire packaged device. On the other hand, the porosity can also be increased by reducing the density of the getter film, thereby increasing the surface area of the getter film. However, if the density is too loose, the mechanical properties of the film will be deteriorated, and the film will easily crack and fall off, thereby affecting the usability.

As shown in FIGS. 1 to 9 , the present invention provides a method for manufacturing a getter thin film structure. The manufacturing method includes the steps of: providing a substrate, and forming a first getter thin film on one main surface of the substrate. Layer, forming a plurality of grooves arranged at intervals in the first getter thin layer to form a patterned getter thin layer; filling the patterned sacrificial layer in the grooves, and filling the patterned sacrificial layer and a second getter thin layer is formed on the pattern getter film; the pattern sacrificial layer is removed to form pores 41 in the in-plane direction of the pattern getter thin layer, and the pores 41 are formed in the pattern The side of the getter thin layer has openings.

In one embodiment, the manufacturing method may include the following steps: 1) forming a first getter thin layer above the substrate, and forming a plurality of grooves arranged at intervals in the getter thin layer , to form a graphic getter thin layer; 2) fill the first graphic sacrificial layer in the groove of the graphic getter thin layer; 3) repeat the above steps to form N graphic getter thin layers and N-1 pattern sacrificial layers, wherein N≥2, no pattern sacrificial layer needs to be formed on the topmost described pattern getter thin layer; The in-plane direction of the getter sheet forms pores 41 which have openings on the sides of the graphic getter sheet.

In one embodiment, the substrate may be a silicon substrate, a glass substrate, a quartz substrate, or a metal cover for MEMS packaging.

In one embodiment, the pores penetrate both sides of the graphic getter thin layer in the in-plane direction of the graphic getter thin layer to form openings on both sides of the graphic getter thin layer , so that a transverse channel is formed in the getter thin layer, and the transverse channel is a structure through which two ends pass through, which can effectively increase the flow velocity of the gas, thereby increasing the getter velocity of the getter thin layer.

In one embodiment, the projections of the pores in two adjacent graphic getter thin layers on the substrate have intersections. For example, the intersecting angles of the projections of the pores in two adjacent graphic getter thin layers on the substrate can be 30 degrees, 45 degrees, 60 degrees, 90 degrees, etc. In a specific implementation process, the relative The projections of the pores in the adjacent two graphic getter thin layers on the substrate intersect vertically.

In one embodiment, the length of the pores in the in-plane direction of the graphic getter thin layer is not less than the thickness of the graphic getter thin layer, so as to ensure at least the getter of the graphic getter thin layer Air capacity and inhalation speed.

In one embodiment, the width of the pores in the in-plane direction of the graphic getter thin layer is not less than 50 nm, for example, the width of the pores in the in-plane direction of the graphic getter thin layer may be 80nm, 100nm, 150nm, etc., this width range can ensure the specific surface area of the graphic getter thin layer on the one hand, and can ensure the mechanical strength of the graphic getter thin layer on the other hand.

In one embodiment, before the formation of the first getter thin layer, it further comprises the step of: forming an underlying getter thin layer over one main surface of the substrate, and the underlying getter thin layer can be patterned , it is also possible to get air through the pores above it (the pores in the first layer of getter thin layer) without patterning, so as to improve the getter capacity of the getter film structure while making better use of the space .

In one embodiment, the getter thin layer is formed by sputtering or vacuum evaporation.

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

In one embodiment, the pattern sacrificial layer includes one of a pattern formed by photoresist and a pattern formed by polyimide.

In one embodiment, the pattern sacrificial layer includes a pattern formed by a silicon compound, and the silicon compound and the getter thin layer have a selectivity ratio in the same etching process, and the selectivity ratio is, for example, greater than 50: 1.

In one embodiment, the material of the getter thin layer can be a Zr-based non-evaporable getter, for example, materials such as Zr-V-Fe, Zr-Al, Zr-Mn-Fe, or a Ti-based Non-evaporable getters, for example, Ti-Fe-V-Mn, Ti-Mo, Ti-Zr-Ni, etc.

In one embodiment, the thickness of the getter thin layer is 100 nm˜1 μm, and the thickness of the getter thin layer may be 200 nm, 500 nm, 800 nm, etc., for example.

As shown in Figures 1 to 8, wherein, Figure 1 shows a schematic diagram of the three-dimensional structure of the getter film structure 20 prepared in this embodiment, and Figures 2, 3, 4, and 5 show AA' in corresponding steps The schematic diagram of the cross-sectional structure at , and Figures 6, 7, and 8 show the schematic cross-sectional structure at BB' in the corresponding steps. The preparation process of a 5-layer getter film structure 20 will be described in detail below.

As shown in Figure 2, at first step 1) is carried out, a substrate 10 is provided, and at room temperature, a first layer of getter thin layer 21 is sputter deposited on the substrate 10, and the thickness of the getter thin layer can be 100nm ~1 μm. The material of the getter thin layer is a Zr-based non-evaporable getter or a Ti-based non-evaporable getter. Of course, before the first getter thin layer 21 is prepared, a bottom getter thin layer (not shown) may also be formed on one main surface of the substrate 10 .

As shown in Figure 3, then carry out step 2), the first layer of getter thin layer 21 is patterned to form the first layer of figure getter thin layer 21 ', thereby in the first layer of getter thin layer 21 The required pattern of grooves is formed on the surface, and the grooves may completely penetrate the first layer of graphic getter thin layer 21' in the thickness direction, or may not penetrate the first layer of graphic getters in the thickness direction. Thin layer 21', part of the first getter thin layer 21 remains at the bottom of the trench. The width of the grooves may be 50nm-1μm, the number of grooves is not less than 2, and can be specially designed according to actual requirements. The patterning process can use either an etching method or a hard mask method. The etching method is to spin-coat photoresist on the first layer of getter thin layer 21, and then form the required groove on the first layer of getter thin layer 21 through exposure, development and etching, and finally Then remove the photoresist. The hard mask method is to use a patterned metal mask, first deposit a layer of metal on the surface of the first layer of getter thin layer 21 as a mask, and then use an etching method to pattern the metal mask, thereby A patterned metal mask is formed, and then the thin layer of the getter is etched so that the getter film forms a groove pattern, and finally the metal mask is removed.

As shown in Figure 4, then carry out step 3), fill photoresist in the trench position of first layer getter thin layer 21 as first layer figure sacrificial layer 31, the method for photoresist filling can be spin coating process wait.

As shown in FIG. 5, step 4) is then performed, and the second layer of getter thin layer 22 is sputter-deposited on the first graphic getter thin layer 21' again, with a thickness of 100 nm to 1 μm.

As shown in Fig. 6, then proceed to step 5) to pattern the second layer of getter thin layer 22 to form a second layer of graphic getter thin layer 22'. The pattern of the second layer of graphic getter thin layer 22' and the graphic of the first layer of graphic getter thin layer 21' are perpendicular to each other. If there are two getter thin layers in total (N=2), the sacrificial layer can be removed after this step is completed. However, the getter thin layers in this example are 5 layers in total, so the following steps are required.

As shown in Figure 7, proceed to step 6), after the second layer of getter thin layer 22 is patterned, fill the groove of the second layer of getter thin layer 22 with photoresist as the second layer Pattern the sacrificial layer 32 .

As shown in Figure 8, proceed to step 7), repeat steps 1) to step 6), until the third layer of graphic getter thin layer 23' is formed based on the third layer of getter thin layer 23, and the third layer of graphic sacrificial Layer 33, based on the fourth layer of getter thin layer 24 to form the fourth layer of graphic getter thin layer 24', the fourth layer of graphic sacrificial layer 34, based on the fifth layer of getter thin layer 25 to form the fifth layer of graphic getter Aerosol thin layer 25'. There is no need to fill the pattern sacrificial layer in the groove of the fifth layer pattern getter thin layer 25'. The pattern of each patterned getter thin layer is perpendicular to the pattern of the adjacent layer of getter thin layer, thereby effectively improving the mechanical strength of the finally prepared getter thin film structure 20 .

As shown in Figure 9, step 8) is finally carried out. After the deposition and patterning of the five-layer getter thin layer are completed, the wafer is soaked in an organic cleaning tank, and the patterned sacrificial layer is removed by a wet method, and finally the figure 1 is realized. The shown getter film structure 20 has pores 41 (transverse channels). In this embodiment, the projections of the pores 41 of two adjacent getter thin layers on the substrate 10 are vertical. The getter thin film structure 20 prepared by using this scheme can realize the adsorption of a larger amount of gas, and the gas absorption rate is faster than that of the normal thin film getter.

As mentioned above, the manufacturing method of the getter film structure 20 of the present invention has the following beneficial effects:

The present invention provides a getter film structure 20, through which the transverse channels of the getter film are formed through the gaps in the in-plane direction, the specific surface area of the getter film can be increased, and the air-breathing capacity and speed of the getter film can be greatly improved. On the other hand, the getter film structure 20 of the present invention can have sufficient mechanical strength, and the usability is guaranteed. On the other hand, compared with the ordinary getter film, the present invention can use less getter to achieve the same getter effect, thereby reducing the overall cost of the device.

Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial application value.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (14)

1. A manufacturing method of getter film structure, is characterized in that, described manufacturing method comprises steps: A substrate is provided, a first getter thin layer is formed on one main surface of the substrate, and a plurality of grooves arranged at intervals are formed in the first getter thin layer to form a graphic getter thin layer. layer; filling the groove with a patterned sacrificial layer, and forming a second thin layer of getter on the patterned sacrificial layer and the patterned getter film; The patterned sacrificial layer is removed to form voids in the in-plane direction of the patterned getter thin layer, the voids having openings on the sides of the patterned getter thin layer. 2. The manufacturing method of the getter film structure according to claim 1, characterized in that, comprising: forming a first getter thin layer above the substrate, and forming a plurality of grooves arranged at intervals in the getter thin layer to form a graphic getter thin layer; Filling the first pattern sacrificial layer in the groove of the pattern getter thin layer; The above steps are repeated to form N graphic getter thin layers and N-1 graphic sacrificial layers, wherein N≥2, and no graphic sacrificial layer needs to be formed on the top graphic getter thin layer; N-1 of the patterned sacrificial layers are removed to form voids in the in-plane direction of each of the patterned getter thin layers, the voids having openings on the sides of the patterned getter thin layers. 3. The manufacturing method of the getter thin film structure according to claim 2, characterized in that, the pores penetrate the two sides of the graphic getter thin layer in the in-plane direction of the graphic getter thin layer, Openings are formed on both sides of the graphic getter thin layer. 4. The manufacturing method of the getter thin film structure according to claim 2, characterized in that the projections of the pores in two adjacent graphic getter thin layers on the substrate have intersections. 5. The manufacturing method of the getter thin film structure according to claim 4, characterized in that the projections of the pores in two adjacent graphic getter thin layers on the substrate intersect vertically. 6. The manufacturing method of the getter thin film structure according to claim 1, characterized in that, the length of the pores in the in-plane direction of the graphic getter thin layer is not less than the length of the graphic getter thin layer. thickness. 7. The method for manufacturing a getter thin film structure according to claim 1, wherein the width of the pores in the in-plane direction of the graphic getter thin layer is not less than 50 nm. 8. The manufacturing method of the getter thin film structure according to claim 1, characterized in that, before the formation of the first getter thin layer, further comprising the step of: forming a bottom getter layer above one main surface of the substrate Aerosol thin layer. 9. The manufacturing method of the getter thin film structure according to claim 1, characterized in that, the getter thin layer is formed by sputtering. 10. The manufacturing method of the getter thin film structure according to claim 1, characterized in that, the method for removing the patterned sacrificial layer comprises one of a liquid solvent dissolution method and a gas plasma etching method. 11. The manufacturing method of the getter thin film structure according to claim 1, wherein the sacrificial pattern layer comprises one of a pattern formed by photoresist and a pattern formed by polyimide. 12. The method for manufacturing a getter thin film structure according to claim 1, wherein the pattern sacrificial layer comprises a pattern formed by a silicon compound. 13. The manufacturing method of the getter thin film structure according to claim 1, characterized in that, the material of the getter thin layer includes Zr-based non-evaporable getter and Ti-based non-evaporable getter kind of. 14 . The method for manufacturing a getter thin film structure according to claim 1 , wherein the thickness of the getter thin layer is 100 nm˜1 μm.

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