CN117446740A - Thin film getter structure with micro heater and manufacturing method thereof - Google Patents
Thin film getter structure with micro heater and manufacturing method thereof Download PDFInfo
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- CN117446740A CN117446740A CN202210845396.4A CN202210845396A CN117446740A CN 117446740 A CN117446740 A CN 117446740A CN 202210845396 A CN202210845396 A CN 202210845396A CN 117446740 A CN117446740 A CN 117446740A
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- 239000010409 thin film Substances 0.000 title claims abstract description 128
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 19
- 239000010408 film Substances 0.000 claims abstract description 256
- 239000000758 substrate Substances 0.000 claims abstract description 43
- 239000000463 material Substances 0.000 claims description 46
- 238000000034 method Methods 0.000 claims description 30
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 14
- 238000005530 etching Methods 0.000 claims description 13
- 229910000986 non-evaporable getter Inorganic materials 0.000 claims description 13
- 229910052710 silicon Inorganic materials 0.000 claims description 10
- 239000010703 silicon Substances 0.000 claims description 10
- 239000011148 porous material Substances 0.000 claims description 9
- 229910003126 Zr–Ni Inorganic materials 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- 229910052750 molybdenum Inorganic materials 0.000 claims description 5
- 229910021426 porous silicon Inorganic materials 0.000 claims description 4
- 238000001259 photo etching Methods 0.000 claims description 2
- 238000000992 sputter etching Methods 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims 1
- 238000005452 bending Methods 0.000 claims 1
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 claims 1
- 229910052719 titanium Inorganic materials 0.000 claims 1
- 238000001994 activation Methods 0.000 description 20
- 230000004913 activation Effects 0.000 description 18
- 238000004806 packaging method and process Methods 0.000 description 17
- 230000008569 process Effects 0.000 description 13
- 238000010438 heat treatment Methods 0.000 description 11
- 238000012858 packaging process Methods 0.000 description 9
- 239000002131 composite material Substances 0.000 description 8
- 238000005538 encapsulation Methods 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 6
- 229920005591 polysilicon Polymers 0.000 description 6
- 238000007789 sealing Methods 0.000 description 6
- 239000004065 semiconductor Substances 0.000 description 5
- 150000002739 metals Chemical class 0.000 description 4
- 238000005240 physical vapour deposition Methods 0.000 description 4
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 4
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 3
- WYTGDNHDOZPMIW-RCBQFDQVSA-N alstonine Natural products C1=CC2=C3C=CC=CC3=NC2=C2N1C[C@H]1[C@H](C)OC=C(C(=O)OC)[C@H]1C2 WYTGDNHDOZPMIW-RCBQFDQVSA-N 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000005229 chemical vapour deposition Methods 0.000 description 3
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- 230000000087 stabilizing effect Effects 0.000 description 3
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010292 electrical insulation Methods 0.000 description 2
- 238000001755 magnetron sputter deposition Methods 0.000 description 2
- 150000002736 metal compounds Chemical class 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
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- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000005137 deposition process Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
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- 230000003100 immobilizing effect Effects 0.000 description 1
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- 238000010884 ion-beam technique Methods 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 238000009461 vacuum packaging Methods 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/0032—Packages or encapsulation
- B81B7/0035—Packages or encapsulation for maintaining a controlled atmosphere inside of the chamber containing the MEMS
- B81B7/0038—Packages or encapsulation for maintaining a controlled atmosphere inside of the chamber containing the MEMS using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/0083—Temperature control
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
- B81C1/00261—Processes for packaging MEMS devices
- B81C1/00277—Processes for packaging MEMS devices for maintaining a controlled atmosphere inside of the cavity containing the MEMS
- B81C1/00285—Processes for packaging MEMS devices for maintaining a controlled atmosphere inside of the cavity containing the MEMS using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B2207/00—Microstructural systems or auxiliary parts thereof
- B81B2207/09—Packages
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C2203/00—Forming microstructural systems
- B81C2203/01—Packaging MEMS
- B81C2203/0172—Seals
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Computer Hardware Design (AREA)
- Manufacturing & Machinery (AREA)
- Non-Adjustable Resistors (AREA)
Abstract
The present invention provides a thin film getter structure having a micro heater and a method of manufacturing the same, the thin film getter structure having a micro heater comprising: one or more heat elements formed on one main surface side of the substrate, and a getter film formed on the surface of the heat elements, wherein the heat elements include: the thin film resistor 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, wherein the end part of the thin film resistor is exposed from the second insulating film. The main surface side of the substrate is provided with a porous structure, the part of the heat carrier carrying the getter film is positioned above the porous structure, and the part of the heat carrier carrying the getter film is supported on the main surface around the porous structure through a connecting part.
Description
Technical Field
The invention belongs to the field of MEMS device design and manufacture, and particularly relates to a thin film getter structure with a micro heater and a manufacturing method thereof.
Background
Some semiconductor devices, particularly those of the microelectromechanical systems (MEMS: micro Electro Mechanical Systems), require packaging to operate in a vacuum environment. For example, MEMS acceleration sensors, gyroscopes, vacuum gauges with high-speed vibrating components require the vibrating parts to be packaged in a relatively stable vacuum. For another example, a MEMS pressure sensor having a vacuum chamber is required, and a high degree of vacuum is also required in the vacuum chamber, and the degree of vacuum is kept stable. Some infrared sensors also require the device to be packaged in a vacuum chamber of higher vacuum.
In most packages, achieving a higher vacuum is inherently challenging because some residual gas is often trapped within the vacuum chamber during the packaging process. For this reason, it is often necessary to enclose a getter in the vacuum chamber, activate the getter at the same time of encapsulation, or activate the getter after encapsulation is completed, absorb the residual gas in the vacuum chamber, and achieve a higher vacuum degree required to meet the operation of the device. Getters (getters), also known as getters, refer in the field of vacuum technology to materials that are capable of efficiently adsorbing and immobilizing certain or certain gas molecules.
It should be noted that the foregoing description of the background art is only for the purpose of facilitating a clear and complete description of the technical solutions of the present application and for the convenience of understanding by those skilled in the art. The above-described solutions are not considered to be known to the person skilled in the art simply because they are set forth in the background section of the present application.
Disclosure of Invention
The inventors have found that existing getter structures have the following limitations: activation of the getter often requires heating the getter at high temperatures of several hundred degrees, and if the entire packaged device is heated from outside the device, the device itself, the packaging method and the materials must be able to withstand such high temperatures, thus having a significant limitation; in addition, the getter performance after the getter is completely activated is certain, and the vacuum degree in the vacuum cavity cannot be flexibly adjusted according to the requirement.
In order to solve the above problems or similar problems, the present invention is directed to providing a thin film getter structure with a micro heater, which is used for solving the problems that in the prior art, it is difficult to simultaneously satisfy the requirements of devices, packaging methods and materials on high temperature resistance and the vacuum degree in a vacuum cavity cannot be flexibly adjusted during vacuum packaging.
To achieve the above and other related objects, the present invention provides a thin film getter structure having a micro heater, comprising: a substrate; one or more heat elements formed on one main surface side of the substrate; and a getter film formed on the surface of the heat element, wherein the heat element 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, wherein an end portion of the thin film resistor is exposed from the second insulating film to form an electrode. Wherein the one main surface of the substrate has a porous structure, the portion of the heat carrying the getter film is located above the porous structure, and the portion of the heat carrying the getter film is supported on the one main surface around the porous structure by a connection portion.
Optionally, the substrate is composed of silicon, and the porous structure is a porous silicon structure.
Optionally, the pore size of the porous structure is from a few nanometers to tens of micrometers, the porosity is 40% -90%, and the thickness is less than 400 micrometers.
Optionally, the thin film resistor is of a bent or serpentine structure.
Optionally, the thermal conductivity of the second insulating film is greater than or equal to the thermal conductivity of the first insulating film, and the thickness of the second insulating film is less than or equal to the thickness of the first insulating film.
Optionally, the thickness of the first insulating film is between 1 and 20 micrometers, and the thickness of the second insulating film is between 0.2 and 2 micrometers.
Optionally, the material of the getter film includes one of a Zr-based non-evaporable getter including one of Zr-V-Fe, zr-Al, and Zr-Mn-Fe and a Ti-based non-evaporable getter including one of Ti-Fe-V-Mn, ti-Mo, and Ti-Zr-Ni.
As described above, the thin film getter structure with micro heater of the present invention has the following advantageous effects:
the thin film getter structure with the micro heater can be used as a packaging cover plate of the MEMS device, the getter thin film can be arranged towards the inside of a sealing cavity of the packaging structure, and an electrode of a heater can be positioned outside the sealing cavity, so that the getter thin film in the sealing cavity can be heated and activated through the exposed electrode after packaging, the problem that the getter activation process and the packaging process are compatible in temperature and the problem that the getter is damaged by high-temperature baking activation after packaging is solved, the activation temperature of the getter is not required to be close to the packaging process temperature when the packaging process is carried out, and the packaging difficulty of the MEMS device is reduced; in addition, the invention can perform single heating activation or multiple simultaneous heating activation on a plurality of (more than two) getter films in the sealed cavity after encapsulation through the exposed electrodes, so that the plurality of getter films in the sealed cavity can be conveniently and flexibly repeatedly activated and used as required, the requirement of adjusting and stabilizing the internal vacuum degree in a certain range is met, the encapsulation efficiency is greatly improved, and the subsequent use and maintenance of MEMS devices are facilitated; in addition, the porous structure can prevent heat generated by the thin film resistor from losing from the substrate, and the heating efficiency of the thin film resistor on the getter thin film is improved. The invention is suitable for various MEMS devices, has universality and wider application prospect.
Drawings
FIGS. 1 to 9 are schematic views showing a method for manufacturing a thin film getter structure having a micro-heater according to an embodiment of the invention;
FIG. 10 is a schematic top view of a thin film getter structure substrate with a micro-heater according to an embodiment of the invention;
FIG. 11 is a schematic top view of a thin film resistor with a micro-heater thin film getter structure according to an embodiment of the invention;
fig. 12 is a schematic diagram of a hard mask.
Description of element reference numerals
10. Substrate board
11. Porous structure
11a first porous structure
11b second porous structure
12. First insulating film
13. Thin film resistor
13a first film resistor
13b second sheet resistance
14a first electrode
14b second electrode
14c third electrode
15. Second insulating film
16. Getter film
16a first getter film
16b second getter film
17. Heat element
17a first heat
17b second heat
18. Getter film deposition window
A-A' section line
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.
As described in detail in the embodiments of the present invention, the cross-sectional view of the device structure is not partially enlarged to a general scale for convenience of explanation, and the schematic drawings are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.
For ease of description, spatially relative terms such as "under", "below", "beneath", "above", "upper" and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. 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. Furthermore, 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, a structure described as a first feature being "on" a second feature may include embodiments where the first and second features are formed in direct contact, as well as embodiments where additional features are formed between the first and second features, such that the first and second features may not be in direct contact.
It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings rather than the number, shape and size of the components in actual implementation, and the form, number and proportion of each component in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.
Activation of the getter often requires high temperature heating of the getter, in the hundreds of degrees. If the getter is activated while packaging, then the activation temperature of the getter is required to be compatible with the packaging process temperature; if the entire packaged device is heated from the outside, there is a great limitation in that both the MEMS device itself and the packaging method and materials must be able to withstand such high temperatures. Meanwhile, the getter after the getter is completely activated has certain gettering performance, and the vacuum degree in the vacuum cavity cannot be flexibly adjusted according to the requirement.
In order to solve the above-mentioned problems, the present embodiment provides a thin film getter structure having a micro heater, comprising: a substrate; a heater formed on one main surface side of the substrate; and a getter film formed on the surface of the heat element, wherein the heat element 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, wherein an end of the thin film resistor is an electrode exposed from the second insulating film. Wherein the one main surface of the substrate has a porous structure, the portion of the heat carrying the getter film is located above the porous structure, and the portion of the heat carrying the getter film is supported on the one main surface around the porous structure by a connection portion.
In one embodiment, the substrate is comprised of silicon and the porous structure is a porous silicon structure.
In one embodiment, the pore size of the porous structure is several nanometers to several tens micrometers, the porosity is 40% -90%, and the thickness is less than 400 micrometers.
In one embodiment, the thin film resistor includes a bent structure, for example, the thin film resistor is a serpentine structure.
In one embodiment, the thermal conductivity of the second insulating film is greater than or equal to the thermal conductivity of the first insulating film, and the thickness of the second insulating film is less than or equal to the thickness of the first insulating film.
In one embodiment, the thickness of the first insulating film is between 1 and 20 micrometers, and the thickness of the second insulating film is between 0.2 and 2 micrometers.
In one embodiment, the material of the getter film comprises one of a Zr-based non-evaporable getter comprising one of Zr-V-Fe, zr-Al and Zr-Mn-Fe and a Ti-based non-evaporable getter comprising one of Ti-Fe-V-Mn, ti-Mo and Ti-Zr-Ni.
In one specific embodiment, as shown in fig. 9-11, embodiment 1 of the present application provides a thin film getter structure with a micro-heater. Wherein fig. 9 is a cross-sectional view of fig. 10 along section line A-A'. As shown in fig. 9 and 10, the thin film getter structure with a micro heater includes: a substrate 10 including first and second heat elements 17a and 17b formed on one main surface side of the substrate 10; and first and second getter films 16a and 16b formed on surfaces of the first and second heat sinks 17a and 17 b. Wherein the first heat 17a includes: a first insulating film 12 formed on the one main surface of the substrate 10; a first film resistor 13a formed on the upper surface of the first insulating film 12; and a second insulating film 15 covering the first film resistor 13a; the second heat 17b includes: a first insulating film 12 formed on the one main surface of the substrate 10; a second film resistor 13b formed on the upper surface of the first insulating film 12; and a second insulating film 15 covering the second film resistor 13 b. One end of the first thin film resistor 13a is a first electrode 14a exposed from the second insulating film 15, and one end of the second thin film resistor 13b is a second electrode 14b exposed from the second insulating film 15. Wherein the one main surface of the substrate 10 has a first porous structure 11a and a second porous structure 11b, a portion of the first heat spreader 17a carrying the first getter film 16a is located above the first porous structure 11a, a portion of the second heat spreader 17b carrying the second getter film 16b is located above the second porous structure 11b, and a portion of the first heat spreader 17a carrying the first getter film 16a and a portion of the second heat spreader 17b carrying the second getter film 16b are supported by the one main surface around the first porous structure 11a and the second porous structure 11b through a connection portion.
As shown in fig. 9 and 10, the first porous structure 11a and the second porous structure 11b formed on one main surface of the substrate 10 can be designed according to the area and the thermal performance of the thin film getter, and mainly serve two functions. Firstly, mechanical support of the first heat spreader 17a and the first getter film 16a and the second heat spreader 17b and the second getter film 16b is realized, and secondly, excessive downward conduction of heat generated by the first film resistor 13a and the second film resistor 13b is prevented, so that the heat is conducted upwards to the first getter film 16a and the second getter film 16b as much as possible, and the temperature of the first getter film 16a and the second getter film 16b reaches an activation temperature. The interval between the first porous structure 11a and the second porous structure 11b may be designed according to the area, the number of getter films, the size of the MEMS device to be packaged, and the like. Further, the interval width between the first porous structure 11a and the second porous structure 11b may be zero, that is, the first porous structure 11a and the second porous structure 11b may communicate. The thickness of the first porous structure 11a and the second porous structure 11b is, for example, 100 to 150 μm; the pore sizes of the first porous structure 11a and the second porous structure 11b are, for example, several hundred nanometers; the porosity of the first porous structure 11a and the second porous structure 11b is, for example, 60% or more; the interval between the first porous structure 11a and the second porous structure 11b is, for example, 10 to 50 μm.
As shown in fig. 9 and 10, the first insulating film 12 formed on one main surface of the substrate 10 may be designed in material and thickness according to the thermal performance requirements. The main functions are two. One is to achieve electrical insulation between the conductive first and second thin film resistors 13a and 13b and the substrate 10. Secondly, mechanical protection of the first heat 17a and the second heat 17b is achieved. The first insulating film 12 may be a film made of a single material, a composite film made of a plurality of materials, or a composite film formed by stacking a plurality of films made of a single material. One particular example is that the first insulating film 12 is a single film made of an oxide of silicon and has a thickness of 10 μm.
As shown in fig. 9 and 11, the first electrode 14a and the second electrode 14b function to energize the first thin film resistor 13a and the second thin film resistor 13b, respectively. The first thin film resistor 13a and the second thin film resistor 13b function to generate a sufficiently high temperature after power-on to activate the first getter film 16a and the second getter film 16b, respectively, and one configuration of the first thin film resistor 13a and the second thin film resistor 13b is shown in fig. 11. The materials, shapes, etc. of the first and second thin film resistors 13a and 13b may be designed according to the requirements for activating the first and second getter films 16a and 16b. The materials of the first and second thin film resistors 13a, 13b must be able to withstand the temperatures required to activate the first and second getter films 16a, 16b, and the resistances must be sized to produce a sufficiently high temperature to activate the first and second getter films 16a, 16b upon proper energization. The materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b may be metals. For example, the materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b contain one or two or more metals of Pt, W, au, al, cu, ni, ta, ti, cr. The materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b may be semiconductors. For example, the materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b are polysilicon. When the materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b are polysilicon, the polysilicon may be doped as needed to adjust the conductivity thereof. The materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b may also be metal compounds. For example, the materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b are TiN, taAlN. The thicknesses of the first film resistor 13a, the second film resistor 13b, the first electrode 14a, and the second electrode 14b are, for example, 0.2 μm.
The second insulating film 15 formed on the first film resistor 13a and the second film resistor 13b is designed in material and thickness according to the requirements of the thermal performance. The main functions are three. One is to achieve electrical insulation between the electrically conductive first film resistor 13a and the first getter film 16a and between the second film resistor 13b and the second getter film 16b. And secondly, collecting heat generated by the first film resistor 13a and the second film resistor 13b and transmitting the heat to the first getter film 16a and the second getter film 16b, so that the temperature of the first getter film 16a and the second getter film 16b reaches the activation temperature thereof. Third, heat generated from the first and second thin film resistors 13a and 13b is uniformly transferred to the first and second getter thin films 16a and 16b. The second insulating film 15 has a heat conduction capability superior to that of the first insulating film 12, the first porous structure 11a, and the second porous structure 11b, and is advantageous in that heat generated after the first thin film resistor 13a and the second thin film resistor 13b are energized is efficiently conducted to the first getter film 16a and the second getter film 16b. The second insulating film 15 may be a film made of a single material, a composite film made of a plurality of materials, or a composite film formed by stacking a plurality of films made of a single material. For example, the first insulating film 12 is a single film made of an oxide of silicon, and the second insulating film 15 is a single film made of a nitride of silicon. At this time, the film growth conditions of the first insulating film 12 and the second insulating film 15 are adjusted so that the heat conduction of the second insulating film 15 is higher than that of the first insulating film 12. The thickness of the second insulating film 15 is, for example, 0.5 μm.
The first getter film 16a formed on the first heat 17a and the second getter film 16b formed on the second heat 17b are composed of a getter material. The materials, areas and thicknesses of the first getter film 16a and the second getter film 16b are designed according to factors such as the kind and amount of gas to be adsorbed. The areas of the first getter film 16a and the second getter film 16b are smaller than the areas of the first porous structure 11a and the second porous structure 11b, respectively, so that the first getter film 16a and the second getter film 16b can be effectively activated by the first heat 17a and the second heat 17 b. For example, the first getter film 16a and the second getter film 16b may be Zr-based non-evaporable getters, including Zr-V-Fe, zr-Al and Zr-Mn-Fe, zrC, etc. The first getter film 16a and the second getter film 16b may be Ti-based non-evaporable getters, including Ti-Fe-V-Mn, ti-Mo, and Ti-Zr-Ni, among others. The size, the ratio, etc. of the pores of the first getter film 16a and the second getter film 16b can be appropriately adjusted. For example, the ratio of the pores of the first getter film 16a and the second getter film 16b is 40% or more. The thickness of the first getter film 16a and the second getter film 16b is, for example, around 1 micron.
The thin film getter structure with the micro heater can heat and activate the getter thin film in the sealed cavity through the exposed electrode after packaging, and can heat and activate the getter in the cavity singly and repeatedly or repeatedly at the same time according to actual needs. The maximum temperature reached by the first getter film 16a and the second getter film 16b during activation is between 200 ℃ and 1000 ℃. Because of the film structure formed by the first heat spreader 17a and the first getter film 16a, and the second heat spreader 17b and the second getter film 16b, the stress of the whole film needs to be properly considered in design, so that the film is not damaged due to the stress in the manufacturing and using processes.
As described above, the present embodiment provides a thin film getter structure with a micro heater. The structure can meet the activation requirement of the getter while reducing the difficulty of the packaging process to the greatest extent. The structure can be processed by a semiconductor process, and has good mass productivity; in addition, the thin film getter structure with the micro heater can activate the thin film getter at any time when needed, effectively adsorb the gas which is increased in the vacuum cavity along with time, and prolong the service life of the MEMS device sealed in the vacuum cavity together. Meanwhile, the plurality of thermal structures of the embodiment can flexibly perform single heating activation or multiple simultaneous heating activation on the getter film when needed, so that the requirement of adjusting and stabilizing the internal vacuum degree in a certain range is met, and the subsequent use and maintenance of the MEMS device are facilitated.
As shown in fig. 1 to 9, the present embodiment also provides a method for manufacturing a thin film getter structure having a micro heater, the method comprising the steps of: providing a substrate, and corroding one main surface of the substrate to form a porous structure; forming a heat on the porous structure; and forming a getter film on the surface of the heat meter. Wherein the step of forming the heat comprises: forming an insulating film over the porous structure; forming a thin film resistor on the upper surface of the first insulating film; and forming a second insulating film covering the thin film resistor; wherein both ends of the thin film resistor are formed as electrodes exposed from the second insulating film. Wherein a portion of the heat carrying the getter film is located above the porous structure, the portion of the heat carrying the getter film being supported by the one major face around the porous structure by a connection.
In one embodiment, the substrate is comprised of silicon and the porous structure is a porous silicon structure.
In one embodiment, the method of forming the porous structure includes at least one of electrochemical etching, photochemical etching, and ion etching.
In one embodiment, the pore size of the porous structure is several nanometers to several tens micrometers, the porosity is 40% -90%, and the thickness is less than 400 micrometers.
In one embodiment, the thin film resistor includes a bent structure, for example, a serpentine structure.
In one embodiment, the thermal conductivity of the second insulating film is greater than or equal to the thermal conductivity of the first insulating film, and the thickness of the second insulating film is less than or equal to the thickness of the first insulating film.
In one embodiment, the thickness of the first insulating film is between 1 and 20 micrometers, and the thickness of the second insulating film is between 0.2 and 2 micrometers.
In one embodiment, the material of the getter film comprises one of a Zr-based non-evaporable getter comprising one of Zr-V-Fe, zr-Al and Zr-Mn-Fe and a Ti-based non-evaporable getter comprising one of Ti-Fe-V-Mn, ti-Mo and Ti-Zr-Ni.
In one specific embodiment, as shown in fig. 1-9, embodiments of the present application provide a method of fabricating a thin film getter structure having a micro-heater. In this embodiment, in order to highlight the main idea of the present application, the schematic diagram includes only the most basic elements.
The method for manufacturing the thin film getter structure with the micro heater provided by the embodiment comprises the following steps: thinning the substrate 10, etching one main surface of the substrate 10, and forming a first porous structure 11a and a second porous structure 11b; forming first and second heat elements 17a and 17b above the first and second porous structures 11a and 11b, respectively; a first getter film 16a and a second getter film 16b are formed on the surfaces of the first heat spreader 17a and the second heat spreader 17b, respectively. Wherein the step of forming the first heat 17a includes: forming a first insulating film 12 on the one main surface of the substrate 10; then forming a first film resistor 13a on the upper surface of the first insulating film 12; finally, forming a second insulating film 15 covering the first film resistor 13a; the step of forming the second heat 17b includes: forming a first insulating film 12 on the one main surface of the substrate 10; then forming a second sheet resistor 13b on the upper surface of the first insulating film 12; finally, a second insulating film 15 is formed to cover the second film resistor 13 b. The second insulating film 15 is etched to expose the first electrode 14a connected to the first thin film resistor 13a and the second electrode 14b connected to the second thin film resistor 13 b. The present manufacturing method is described step by step below.
First, as shown in fig. 1, a substrate 10 is prepared. In the present embodiment, for brevity and convenience, the present embodiment will be described taking the substrate 10 as an example of a Si substrate conventionally used in semiconductor processes.
Then, as shown in fig. 2, the substrate 10 is thinned. For example, the substrate 10 is thinned by a thinning apparatus and CMP (CMP: chemical mechanical polishing, chemical mechanical polishing), for example, having a thickness of 200 to 700 μm, specifically 400. Mu.m.
Then, as shown in fig. 3, one main surface of the substrate 10 is etched by a general electrochemical etching method to form a first porous structure 11a and a second porous structure 11b. The thickness, pore size and porosity of the first and second porous structures 11a and 11b are designed according to the requirements of the thermal performance. The spacing of the first and second porous structures 11a, 11b may be designed according to the area, number of getter films, the size of the MEMS device to be packaged, etc. The primary function of this is to keep the first getter film 16a and the second getter film 16b from interfering with each other during activation by heating. The first porous structure 11a and the second porous structure 11b may have a thickness of 150 micrometers, a pore size of 200 nanometers, a porosity of 60%, and a spacing of 50 micrometers. The areas of the first porous structure 11a and the second porous structure 11b may be the same or different.
Then, as shown in fig. 4, a first insulating film 12 is formed on the main surface of the substrate 10. The material and thickness of the first insulating film 12 are designed according to the requirements of the thermal performance. For example, the first insulating film 12 may be a silicon oxide film, which may be 2 microns thick, formed using conventional TEOS CVD (TEOS: tetraethyl orthosilicate, CVD: chemical Vapor Deposition) and associated processes. The first insulating film 12 may be a film made of a single material, a composite film made of a plurality of materials, or a composite film formed by stacking a plurality of films made of a single material. One particular example is that the first insulating film 12 is a single film made of an oxide of silicon and has a thickness of 2 μm.
Then, as shown in fig. 5, a conductive film resistor 13 is formed on the first insulating film 12. For example, the conductive sheet resistor 13 may be metallic Ti and may be 0.2 microns thick and formed using conventional PVD (PVD: physical Vapor Deposition, physical vapor deposition) techniques and associated processes.
Then, as shown in fig. 6, the conductive thin film resistor 13 is processed to form conductive first and second thin film resistors 13a and 13b having a meandering structure shown in fig. 11, and first, second and third electrodes 14a, 14b and 14c shown in fig. 10. The processing of the first and second thin film resistors 13a and 13b and the first, second and third electrodes 14a and 14b and 14c may be performed using conventional photolithography and metal etching and associated processes. For example, the metal Etching process may use an Ion Beam Etching (IBE) method or a wet Etching method.
Then, as shown in fig. 7, a second insulating film 15 is formed on the first film resistor 13a and the second film resistor 13 b. The material and thickness of the second insulating film 15 are designed according to the requirements of the thermal performance. For example, the second insulating film 15 may be a silicon nitride film, and the thickness may be 0.4 μm, and the growth is performed by a conventional PECVD (PECVD: plasma Enhanced Chemical Vapor deposition. Chinese: plasma enhanced chemical vapor deposition) method. The second insulating film 15 may be a film made of a single material, a composite film made of a plurality of materials, or a composite film formed by stacking a plurality of films made of a single material. For example, the first insulating film 12 may be a single film composed of an oxide of silicon, and the second insulating film 15 may be a single film composed of a nitride of silicon. At this time, the film growth conditions of the first insulating film 12 and the second insulating film 15 are adjusted so that the heat conduction of the second insulating film 15 is higher than that of the first insulating film 12.
Then, as shown in fig. 8, the second insulating film 15 is etched to expose the first electrode 14a, the second electrode 14b, and the third electrode 14c. For example, etching the second insulating film 15 may be performed using conventional photolithography and dielectric layer etching, and a complementary process. For example, the dielectric layer etching process may use a plasma etching method.
In the present embodiment, the first electrode 14a and the second electrode 14b function to energize the first thin film resistor 13a and the second thin film resistor 13b, respectively. The first and second thin film resistors 13a and 13b function to generate a sufficiently high temperature upon energization to activate the first and second getter films 16a and 16b, respectively. Therefore, the materials, shapes, etc. of the first thin film resistor 13a and the second thin film resistor 13b may be designed according to the requirements of activating the first getter film 16a and the second getter film 16b. The materials of the first and second thin film resistors 13a, 13b must be able to withstand the temperatures required to activate the first and second getter films 16a, 16b, and the resistances must be sized to produce a sufficiently high temperature to activate the first and second getter films 16a, 16b upon proper energization. The materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b may be metals. For example, the materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b contain one or two or more metals of Pt, W, au, al, cu, ni, ta, ti, cr. The materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b may be semiconductors. For example, the materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b are polysilicon. When the materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b are polysilicon, the polysilicon may be doped as needed to adjust the conductivity thereof. The materials of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b may be metal compounds. For example, the materials of the first thin film resistor 13a and the second thin film resistor 13b are TiN, taAlN. The thicknesses of the first thin film resistor 13a, the second thin film resistor 13b, the first electrode 14a, and the second electrode 14b may be, for example, 0.2 μm.
Then, as shown in fig. 9, the first getter film 16a and the second getter film 16b are formed on the first heater 17a and the second heater 17b, and finally, a thin film getter structure having a micro heater is formed. The areas of the first getter film 16a and the second getter film 16b are smaller than the areas of the first porous structure 11a and the second porous structure 11b, respectively. The materials and thicknesses of the first and second getter films 16a, 16b are designed according to the type and amount of gas to be adsorbed, for example, the first and second getter films 16a, 16b may be Zr-based non-evaporable getter materials including ZrVFe, having a thickness of about 1 micron. The first getter film 16a and the second getter film 16b may be deposited on the second insulating film 15 using a magnetron sputtering method. In the first getter film 16a and the second getter film 16b deposition process, a hard mask (shown in fig. 12) may be coated on the surface of the substrate after the process shown in fig. 8 is completed. The window 18 is opened in the portion of this hard mask opposite to the first getter film 16a and the second getter film 16b shown in fig. 9, so that the first getter film 16a and the second getter film 16b can be deposited on top of the second insulating film 15 through the window 18 during magnetron sputtering. The use of a hard mask has the advantage that no etching process is required for the first getter film 16a and the second getter film 16b, avoiding possible contamination of the first getter film 16a and the second getter film 16b during the etching process. Another benefit of using a hard mask is that the formation process of the first getter film 16a and the second getter film 16b is simple, the hard mask can be used repeatedly, and the manufacturing cost is reduced.
As described above, the present embodiment provides a method for manufacturing a thin film getter structure having a micro heater, which is simple and low in manufacturing cost. A plurality of thin film getter structures having micro-heaters can be simultaneously manufactured on one substrate, and mass productivity is achieved. The present application has been described in connection with specific embodiments, but it should be apparent to those skilled in the art that these descriptions are intended to be illustrative and not limiting. Various modifications and alterations of this application may occur to those skilled in the art in light of the spirit and principles of this application, and are to be seen as within the scope of this application.
As described above, the microelectronic device airtight packaging structure with adjustable vacuum degree in the cavity has the following beneficial effects:
the thin film getter structure with the micro heater can be used as a packaging cover plate of the MEMS device, the getter thin film can be arranged towards the inside of a sealing cavity of the packaging structure, and an electrode of a heater can be positioned outside the sealing cavity, so that the getter thin film in the sealing cavity can be heated and activated through the exposed electrode after packaging, the problem that the getter activation process and the packaging process are compatible in temperature and the problem that the getter is damaged by high-temperature baking activation after packaging is solved, the activation temperature of the getter is not required to be close to the packaging process temperature when the packaging process is carried out, and the packaging difficulty of the MEMS device is reduced; in addition, the invention can perform single heating activation or multiple simultaneous heating activation on a plurality of (more than two) getter films in the sealed cavity after encapsulation through the exposed electrodes, so that the plurality of getter films in the sealed cavity can be conveniently and flexibly repeatedly activated and used as required, the requirement of adjusting and stabilizing the internal vacuum degree in a certain range is met, the encapsulation efficiency is greatly improved, and the subsequent use and maintenance of MEMS devices are facilitated; in addition, the porous structure can prevent heat generated by the thin film resistor from losing from the substrate, and the heating efficiency of the thin film resistor on the getter thin film is improved. The invention is suitable for various MEMS devices, has universality and wider application prospect.
Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (9)
1. A thin film getter structure having a micro-heater comprising:
a substrate;
one or more heat elements formed on one main surface side of the substrate; and
a getter film formed on the surface of the heat element,
wherein the heat 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,
an end portion of the thin film resistor is exposed from the second insulating film,
wherein the one main surface of the substrate has a porous structure, the portion of the heat carrying the getter film is located above the porous structure, and the portion of the heat carrying the getter film is supported on the one main surface around the porous structure by a connection portion.
2. The thin film getter structure of a microheater as in claim 1, wherein,
the substrate is composed of silicon, and the porous structure is a porous silicon structure.
3. The thin film getter structure of a microheater as in claim 1, wherein,
the pore size of the porous structure is from a few nanometers to tens of micrometers, the porosity is 40% -90%, and the thickness is less than 400 micrometers.
4. The thin film getter structure of a microheater as in claim 1, wherein,
the thin film resistor is of a bending structure.
5. The thin film getter structure of a microheater as in claim 1, wherein,
the material of the getter film comprises one of a zirconium (Zr) based non-evaporable getter and a titanium (Ti) based non-evaporable getter, the Zr based non-evaporable getter comprises at least one of Zr-V-Fe, zr-Al and Zr-Mn-Fe, and the Ti based non-evaporable getter comprises at least one of Ti-Fe-V-Mn, ti-Mo and Ti-Zr-Ni.
6. A method of fabricating a thin film getter structure having a micro-heater, comprising:
etching one main surface of the substrate to form a porous structure;
forming one or more heat elements over the porous structure;
a getter film is formed on the surface of the heat meter,
wherein the step of forming the heat comprises:
forming an insulating film over the porous structure;
forming a thin film resistor on the upper surface of the first insulating film; and
forming a second insulating film covering the film resistor,
wherein an end portion of the thin film resistor is formed to be exposed from the second insulating film.
7. The method of fabricating a thin film getter structure having a micro-heater as recited in claim 6, wherein,
the method of forming the porous structure includes at least one of electrochemical etching, photochemical etching, and ion etching.
8. The method of fabricating a thin film getter structure having a micro-heater as recited in claim 6, wherein,
the thermal conductivity of the second insulating film is greater than or equal to that of the first insulating film, and the thickness of the second insulating film is less than or equal to that of the first insulating film.
9. The method of fabricating a thin film getter structure having a micro-heater as recited in claim 8, wherein,
the thickness of the first insulating film is 1-20 micrometers, and the thickness of the second insulating film is 0.2-2 micrometers.
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