CN116121706A - Getter film for improving getter capacity of carbon-containing gas - Google Patents

Getter film for improving getter capacity of carbon-containing gas Download PDF

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Publication number
CN116121706A
CN116121706A CN202310088961.1A CN202310088961A CN116121706A CN 116121706 A CN116121706 A CN 116121706A CN 202310088961 A CN202310088961 A CN 202310088961A CN 116121706 A CN116121706 A CN 116121706A
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Prior art keywords
getter
film
carbon
molybdenum
capacity
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CN202310088961.1A
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Chinese (zh)
Inventor
郭卫斌
薛函迎
柴云川
王浏杰
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NANJING HUADONG ELECTRONICS VACUUM MATERIAL CO Ltd
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NANJING HUADONG ELECTRONICS VACUUM MATERIAL CO Ltd
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Priority to CN202310088961.1A priority Critical patent/CN116121706A/en
Publication of CN116121706A publication Critical patent/CN116121706A/en
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • C23C14/14—Metallic material, boron or silicon
    • C23C14/16—Metallic material, boron or silicon on metallic substrates or on substrates of boron or silicon
    • C23C14/165—Metallic material, boron or silicon on metallic substrates or on substrates of boron or silicon by cathodic sputtering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • 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
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C14/00—Alloys based on titanium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C16/00—Alloys based on zirconium
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • C23C14/14—Metallic material, boron or silicon
    • C23C14/18—Metallic material, boron or silicon on other inorganic substrates
    • C23C14/185—Metallic material, boron or silicon on other inorganic substrates by cathodic sputtering
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/34—Sputtering
    • C23C14/35—Sputtering by application of a magnetic field, e.g. magnetron sputtering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
    • B01J2220/48—Sorbents characterised by the starting material used for their preparation
    • B01J2220/4806—Sorbents characterised by the starting material used for their preparation the starting material being of inorganic character

Abstract

The invention relates to a getter film for improving the getter capacity of carbon-containing gas, which is formed by depositing a getter film of 0.1-15 mu m on the surface of a stainless steel, kovar, silicon, germanium and ceramic substrate by a PVD method, wherein the getter film comprises one or two of titanium and zirconium, and comprises tungsten and molybdenum or any proportion thereof accounting for 0.5-20 percent of the total weight of the getter film, and optional componentsVanadium, manganese, cobalt, yttrium, aluminum; compared with the prior art, the getter film of the invention has the advantages of reducing the CO and CO 2 、CH 4 The gettering capacity of the carbon-containing gas is improved by 30-50%, and the carbon-containing gas is applied to MEMS devices with chips fixed by an organic adhesive mode.

Description

Getter film for improving getter capacity of carbon-containing gas
Technical Field
The invention relates to the technical field of electronic element materials, in particular to a getter film for improving the getter capacity of carbon-containing gas.
Background
The preparation or device for obtaining, maintaining vacuum, purifying gas, etc., which is effective in adsorbing certain gas molecules is generally called a getter. Common getters are mainly: the method comprises the following steps: the mixture of aluminum alloy of metals such as barium, strontium, calcium and the like and reducing agents such as iron powder, nickel powder and titanium powder is heated in vacuum, so that active metals such as barium, strontium, calcium and the like in the mixture are evaporated and condensed on the inner wall of the device to form a getter film, and the most widely used mixture of the barium aluminum alloy and the nickel powder. Non-evaporable getter: the powder sintered body of zirconium, titanium and yttrium simple substance powder or binary or multi-element alloy composed of the powder, vanadium, iron, manganese, cobalt, aluminum, molybdenum and rare earth is heated in vacuum, so that an oxide layer on the surface of the powder is diffused inwards to expose fresh surfaces, and the zirconium-aluminum alloy and the zirconium-vanadium-iron alloy are the most widely used.
In recent years, with the miniaturization, flattening and integration of traditional electric vacuum devices and various sensors and MEMS devices, the required getter is gradually changed from a vapor-evaporation type to a non-vapor-evaporation type, the processing mode of the getter is changed from a traditional sintering type cylinder and thick film to a PVD deposited thin film and then integrated on a wafer, and the dimension of the getter in the thickness direction is also changed from a few millimeters to hundreds of micrometers and then to a few micrometers.
The getter films have a certain capability of absorbing active gases after being activated as common non-evaporable getters, and the getters have different capability of absorbing different gases. In general, the getters have the strongest gettering capability for pure hydrogen and can absorb until the gettering alloy is completely hydrogenated. The ability to inhale carbonaceous gases, particularly gases such as methane hydrocarbons, is extremely limited. At the same time, the getters can interfere with each other in absorbing the mixed gas, for example, the getters can cause a great reduction in hydrogen absorption capacity after absorbing a small amount of CO.
For example, chinese patent 200410049383 discloses a non-evaporable getter multilayer deposit obtained by cathodic deposition and a method for its manufacture, by depositing a layer of titanium as the main getter layer on a substrate by means of magnetron sputtering, followed by a thin getter layer capable of being activated at low temperature, to prepare a composite getter film.
For another example, chinese patent 201610916723 discloses a method of evaporating pure metal and NaCl by electron beam, then dissolving NaCl with water to obtain a porous conditioning layer, and then depositing a zirconium cobalt rare earth thin film on the conditioning layer by magnetron sputtering.
For another example, chinese patent 201811622378 discloses a sandwich structure of an air-absorbing film, which comprises depositing a dense layer of titanium as a barrier layer on a substrate to prevent the impurity gas emitted from the substrate from poisoning the air-absorbing layer during activation, and which is also beneficial to adjusting the microstructure of the air-absorbing film; then depositing a zirconium cobalt rare earth gas absorbing layer on the barrier layer; finally, a thin noble metal palladium layer is deposited as a protective layer, so that oxidation caused by long-term exposure of the open surface of the air suction layer to the atmosphere is avoided.
The prior art mainly adopts structural adjustment to increase the microscopic surface area of the air suction film or to increase the protective layer on the surface to improve the air suction capability of the air suction film.
However, the current MEMS devices are mainly encapsulated by ceramics, and the chip is generally bonded to the ceramic housing by using an organic fixing adhesive. These organic fixing gums are generally cured by an inert atmosphere or vacuum baking at 100-200 ℃ for a prolonged period of time. These organic substances release a large amount of CO and CO in vacuum, especially under the condition of being heated 2 CmHn, these gases are the primary sources of gas during the lifetime of the MEMS device. Because of the difficulty in chemisorption, it is difficult to effectively increase its gettering capacity simply by increasing the microscopic surface area of the gettering film. Therefore, improving the composition of the getter film and the gettering capability of the getter film to the carbon-containing gas are main methods for improving the internal vacuum degree and the service life of the MEMS packaging device.
Disclosure of Invention
Aiming at the defects of the prior art, the invention innovatively provides the air suction film for improving the air suction capacity of the carbon-containing gas, which can solve the defects of large carbon-containing gas release amount caused by a chip fixing mode in the prior MEMS packaging technology and low air suction capacity of the prior air suction film technology on the carbon-containing gas.
The technical solution of the invention is as follows: the surface of the stainless steel, kovar, silicon, germanium and ceramic substrate is deposited with a 0.1-15 mu m getter film by a PVD method, wherein the getter film comprises one or two of titanium and zirconium, and contains tungsten, molybdenum or any proportion of tungsten, molybdenum and optional vanadium, manganese, cobalt, yttrium and aluminum, wherein the weight percentage of the tungsten, the molybdenum and the combination of any proportion of the tungsten, the molybdenum and the yttrium is 0.5-20% of the total weight of the getter film.
Further, the getter film is a multi-layer film structure, and comprises a barrier layer or a protective layer besides the getter layer, wherein one or more layers of the getter layer comprise one or two of titanium and zirconium, and simultaneously comprise tungsten, molybdenum or any proportion of tungsten, molybdenum or any combination of tungsten, manganese, cobalt, yttrium and aluminum, wherein the weight percentage of the tungsten, molybdenum or any proportion of the tungsten, molybdenum, yttrium and aluminum is 0.5-20% of the total weight of the getter film.
Further, the getter film is a multi-layer film structure, and one or more layers of the multi-layer film are molybdenum, tungsten or a combination thereof.
Further, the getter film also comprises 1-5% by weight of rare earth.
Further, the PVD method is magnetron sputtering.
The invention has the beneficial effects that: in the case of the same thickness of the getter film, compared with the prior art, the getter film of the invention has the advantages of CO and CO 2 、CH 4 The gettering capacity of the carbon-containing gas is improved by 30-50%, and the carbon-containing gas is applied to MEMS devices with chips fixed by an organic adhesive mode.
Detailed Description
Unlike available sintered getter, the present invention is formed through sintering molybdenum powder, titanium powder, zirconium powder and tungsten powder. Wherein molybdenum and tungsten are used as anti-sintering agents, so that the specific surface areas of titanium powder and zirconium powder are prevented from being greatly reduced during high-temperature sintering. The molybdenum and tungsten in the particle state in the sintered getters were found to have no significant gettering capability in the comparative test.
The invention has no specific limitation on the production mode of the air suction film, and the conventional PVD film plating methods such as evaporation, magnetron sputtering and the like can be produced. The magnetron sputtering method is most suitable from the viewpoint of film production, can precisely control the grain size and the film thickness of the film layer, and has a plurality of difficulties in adopting an evaporation method due to the higher melting points of tungsten and molybdenum.
When the magnetron sputtering method is adopted to produce the getter film, the specific target material is not limited. In consideration of the high melting point of tungsten and molybdenum and the problem of production efficiency, the powder metallurgy method is adopted to produce the getter alloy target material containing tungsten and molybdenum. Films obtained by co-sputtering a getter alloy target containing no tungsten or molybdenum with an elemental tungsten or molybdenum target also exhibit excellent gettering capabilities for carbon-containing gases.
In the invention, the weight percentage of tungsten and molybdenum has great influence on the performance of the air suction film. Experiments show that although the contents of tungsten and molybdenum can improve the gettering capacity of the gettering film to carbon-containing gas in a wide range, the optimal contents are about 5%.
When a multilayer film structure is adopted, tungsten and molybdenum are added in the main air suction layers or are clamped between the two main air suction layers. Tungsten, molybdenum added to the barrier layer and the protective layer have no effect as described in the present invention.
After tungsten and molybdenum are added into the getter alloy, the activation temperature of the getter film is not obviously changed, and rare earth can be added into the getter alloy to reduce the activation temperature of the getter film.
Like most getter films, the grain size of the getter alloys of the invention has a significant effect on the temperature and time required for activation. Therefore, the conventional method for reducing the grain size of the getter alloy and increasing the specific surface area of the getter alloy is effective for improving the performance of the getter film of the invention, and can be used in combination.
The technical scheme of the invention is further described below according to examples.
Example 1
The titanium-molybdenum alloy target was prepared by powder metallurgy, wherein the weight percentage of molybdenum was 5%, and the process of producing an gettering film using the molybdenum-titanium target of this example, which was based on stainless steel having a thickness of 0.05mm, was performed with magnetron sputtering for 2 hours to obtain a gettering film having a grain size of about tens of nm and a thickness of about 2 μm as sample 1.
Example 2
This example is prior art for comparison. The procedure of example 1 was repeated using a 5N elemental titanium target to obtain a getter film having a grain size of about tens of nm and a thickness of about 2. Mu.m, as sample 2.
Example 3
This example is prior art for comparison. Mixing 90% by weight of titanium powder and 10% by weight of molybdenum powder uniformly. Taking 2.1g of mixed powder, and using 1T/cm 2 A disc-shaped preform having a diameter of 2.5cm was prepared. Sintering the pressed blank for 30min at 1000 ℃. After cooling to room temperature in vacuo, the sample was taken out as sample 3.
Example 4
This example is prior art for comparison. 2.1g of the titanium powder of example 3 was taken and used at 1T/cm 2 A disc-shaped preform having a diameter of 2.5cm was prepared. To ensure the same specific surface area as in example 3, the green compacts were sintered in vacuo at 800℃for 30min. After cooling to room temperature in vacuo, the sample was taken as sample 4. Sample 4 has substantially the same specific surface area and lower strength than sample 3.
Example 5
In this example, CO was used as the test gas, and the suction capacity of samples 1 to 4 was measured by the constant volume method. Samples 1-4 were tested sequentially as follows:
the test specimen is first enclosed in a vacuum chamber of fixed volume and then baked out of the test system. After cooling the system, it was activated at 450℃for 30min. After the sample has cooled to room temperature, the system is charged with a known amount of CO. After the pressure of the system is balanced, the residual pressure inside the system is measured. The difference between the number of charged systems and the number of residues in the systems is the inspiratory capacity of the CO of the test.
Test conditions and results (unit: pa×L/cm) 2 ) As shown in table 1 below:
Figure BDA0004069661630000041
Figure BDA0004069661630000051
TABLE 1
As can be seen from table 1, sample 1 had an increase in CO gettering capacity of about 50% over sample 2 under otherwise identical conditions, indicating that molybdenum is involved in the gettering process.
As is clear from the comparison data of sample 3 and sample 4, the intake capacity did not rise significantly after about 10% of molybdenum was added, and the test value of sample 3 was about 90% of the test value of sample 4, which is close to the titanium content in sample 3, indicating that granular molybdenum did not participate in the intake process, thus demonstrating that the present invention is different from the prior art. The effect of the molybdenum added to sample 3 is to reduce the reduction of the specific surface area of the titanium particles as much as possible while obtaining satisfactory mechanical strength at the time of high temperature sintering.
The comparative data for sample 1 and sample 3, although close, are not comparable, as sample 1 is only about 2 μm thick, whereas sample 3 is about 1.5mm thick.
The embodiments of the invention disclosed above are intended only to help illustrate the invention. The examples are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best understand and utilize the invention. The invention is limited only by the claims and the full scope and equivalents thereof.

Claims (5)

1. A getter film for increasing the getter capacity of carbon-containing gases, characterized in that the surface of a substrate of stainless steel, kovar, silicon, germanium and ceramics is deposited with a getter film of 0.1-15 μm by a PVD method, the getter film comprises one or two of titanium and zirconium, and contains tungsten, molybdenum or any proportion of tungsten, manganese, cobalt, yttrium and aluminum, in a weight percentage of 0.5-20% of the total weight of the getter film.
2. The getter film for increasing the getter capacity of carbon-containing gases according to claim 1, consisting of a multilayer film, comprising, in addition to the getter layer, a barrier layer or a protective layer, one or more of the getter layers comprising one or both of titanium, zirconium, and tungsten, molybdenum or any ratio of combinations thereof, in weight percentages ranging from 0.5 to 20% of the total weight of the getter film, and optionally vanadium, manganese, cobalt, yttrium, aluminum.
3. The getter film for increasing the getter capacity of carbon-containing gases according to claim 1, wherein the getter film has a multi-layered film structure, and one or more layers of the multi-layered film is molybdenum, tungsten or a combination thereof.
4. The getter film for increasing the getter capacity of carbon-containing gases according to claim 1, wherein the getter film further comprises 1-5% by weight of rare earth.
5. The getter film for increasing the getter capacity of carbon-containing gases according to claim 1, wherein the PVD process is magnetron sputtering.
CN202310088961.1A 2023-02-09 2023-02-09 Getter film for improving getter capacity of carbon-containing gas Pending CN116121706A (en)

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