Low-temperature activated air suction film and production method thereof

Abstract

The invention relates to the field of electronic component materials, and discloses a low-temperature activated air suction film and a production method thereof, the low-temperature activated air suction film comprises an air suction layer, the air suction layer is made of a titanium-zirconium-yttrium alloy film, and the titanium-zirconium-yttrium alloy film is a film generated by deposition of titanium atoms, zirconium atoms and a set amount of yttrium atoms on the surface of a substrate; a substrate of the air suction layer is made of stainless steel, kovar, silicon, germanium or ceramic; the air suction layer is prepared through a magnetron sputtering process, the film thickness of the air suction layer is 0.1-10 microns, the air suction layer comprises crystal grains, and the size of the crystal grains is 5-300 nanometers. The activation temperature of the film can be effectively reduced, and meanwhile the quality of a finished product can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic component materials, and particularly relates to a low-temperature-activated getter film and a production method thereof. Background Art

[0002] In recent years, with the miniaturization, flattening, and integration of traditional electro-vacuum devices, various sensors, and MEMS devices, the getter required has gradually changed from mainly evaporation type to mainly non-evaporation type. Its shape has also developed from the traditional cylindrical shape to thick films and thin films in the form of flakes, and then integrated on wafers. The size of the getter in the thickness direction has also developed from several millimeters to several hundred micrometers, and then to several micrometers.

[0003] To enable these getters to work properly, they need to be heated in a vacuum or inert gas for a period of time so that carbon and oxygen on the surface of the getter diffuse into the interior, thereby exposing the active getter surface. This process is called activation. Different getter alloys require different combinations of activation temperature and time. For example, the zirconium-aluminum getter alloy requires several hours at 750°C, or 30 seconds at 900°C; the zirconium-vanadium-iron alloy requires 10 minutes at 500°C, or several hours at 400°C. Generally speaking, the higher the activation temperature, the shorter the required time. For the same alloy, different getter morphologies also require different activation temperatures. For example, for zirconium-cobalt-rare earth getters, products pressed in powder form require 350°C - 400°C for dozens of minutes, while getter films with a grain size of dozens of nanometers obtained by magnetron sputtering can be activated at 300°C for 30 minutes.

[0004] In recent years, as MEMS devices have developed from metal packaging to ceramic packaging and then to wafer-level packaging, the allowable activation temperature of the getter has become lower and lower. With the shortening of the manufacturing process time, the required activation time of the getter has also become shorter and shorter. The current mainstream packaging process requires the getter to be activated within 30 minutes between 280°C and 350°C.

[0005] Currently, to activate the getter at low temperature, the following technical approaches are mainly available: The first is to use a ternary alloy of titanium, zirconium, and vanadium or a quaternary alloy of titanium, zirconium, hafnium, and vanadium. The sheet-shaped getter pressed from its alloy powder requires 400 to 450°C for dozens of minutes for activation. However, when sputtering with it as a target, due to its grain size of several nanometers and high vanadium content, it can be activated at a minimum of 160 - 180°C. However, at this low temperature, its activation time is quite long and needs to be maintained for more than 2 hours. Such a long activation time can only be applied in some special test devices and cannot be used in occasions with requirements for packaging time such as MEMS devices. And the vanadium metal used is not environmentally friendly. Although it has excellent getter ability for carbon monoxide, its getter ability for hydrogen, the main residual gas in vacuum devices, is relatively low.

[0006] Secondly, zirconium-cobalt-rare earth alloy is used. Since the rare earth in it has relatively high activity, the sheet getter made of zirconium-cobalt-rare earth powder can be activated at 350 to 400 °C for 30 minutes. When zirconium-cobalt-rare earth alloy is used as a target for sputtering, a thin film getter with grain size of dozens of nanometers can be obtained, and the activation temperature can be further reduced to 250 to 300 °C. This is also the most important getter material currently used in wafer-level packaging. However, when processing this getter alloy, the internal stress is relatively large, and it is easy to crack when making large-sized targets. Usually, it needs to be bonded to a backplane for use. Moreover, due to the internal stress of the sputtered thin film, it is also easy to crack and peel off when the thickness exceeds 3 microns. This also limits the large getter capacity that can be obtained per unit area of the getter film.

[0007] To solve these problems, Chinese Patent 200410049383 discloses a non-evaporable getter multi-layer deposit obtained by cathode deposition and its manufacturing method. A layer of titanium is deposited on a substrate as the main getter layer by magnetron sputtering, and then a very thin getter layer that can be activated at low temperature is deposited to prepare a composite getter film. This method can obtain a lower activation temperature and a higher getter capacity. However, compared with a single-layer getter thin film, the reduction of its activation temperature is extremely limited. And two different targets need to be equipped in its production equipment, so the size of the target is limited. Due to the requirement of coating uniformity, the number of products coated in each furnace is also limited. The two films need to be produced successively, resulting in low efficiency.

[0008] Chinese Patent 201610916723 discloses a method of electron beam evaporating pure metal and NaCl, then dissolving NaCl in water to obtain a porous adjustment layer, and then magnetron sputtering and depositing a zirconium-cobalt-rare earth thin film on the adjustment layer. Although this method solves the problem of stress matching between the zirconium-cobalt-rare earth thin film and the substrate, its manufacturing process is cumbersome, and it is necessary to frequently enter and exit the vacuum equipment for processing, resulting in low efficiency. And although it benefits from the existence of the porous adjustment layer and can be activated at 200 °C for 90 minutes, the getter ability of the product at this time is extremely limited. If the getter film wants to obtain satisfactory getter ability, it needs to be maintained at 300 °C for about 45 minutes.

[0009] Chinese Patent No. 201811622378 discloses a sandwich-structured getter film. First, a dense titanium layer is deposited on a substrate as a barrier layer to prevent impurity gases released from the substrate during activation from poisoning the getter layer. At the same time, it is also beneficial for adjusting the microstructure of the getter film. Then, a zirconium-cobalt-rare earth getter layer is deposited on the barrier layer. Finally, a thin layer of noble metal palladium is deposited as a protective layer to prevent oxidation caused by the long-term exposure of the open surface of the getter layer to the atmosphere. Although this sandwich structure enables the getter film to absorb hydrogen at a lower temperature, due to the barrier of metal palladium, its absorption of carbon monoxide is limited. And during its production process, at least three kinds of targets need to be arranged in a vacuum chamber, and they also need to be coated successively, resulting in low production efficiency.

[0010] And these measures do not fundamentally solve the problem of large internal stress in the zirconium-cobalt-rare earth alloy. The thickness of the deposited film layer is greatly limited, and it is difficult to increase the getter capacity by increasing the film layer thickness per unit area. When manufacturing a zirconium-cobalt-rare earth target, large-sized targets must be bound to a backplane for use, and the yield of the casting and binding process is also very low, and cracks and other defects are likely to occur during use. Summary of the Invention

[0011] Aiming at the above-mentioned existing technical deficiencies, the technical problem to be solved by the present invention is to provide a getter film activated at low temperature and its production method, aiming to solve the technical problems of high alloy activation temperature and long activation time existing in the existing getter films.

[0012] To solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a getter film activated at low temperature, including: a getter layer, the material of the getter layer is a titanium-zirconium-yttrium alloy film, and the titanium-zirconium-yttrium alloy film is a film generated by depositing titanium atoms, zirconium atoms and a set amount of yttrium atoms on the surface of a substrate; the substrate of the getter layer is stainless steel, kovar, silicon, germanium or ceramic; The getter layer is prepared by a magnetron sputtering process, the film thickness of the getter layer is from 0.1 micrometer to 10 micrometers, and the getter layer includes grains, and the size of the grains is from 5 to 300 nanometers.

[0013] Further, the film thickness of the getter layer is from 2 micrometers to 4 micrometers.

[0014] Further, the size of the grains is 10 nanometers.

[0015] A production method of a getter film activated at low temperature includes the following steps: S1. Substrate preparation, preparing a substrate for reaction; S2. Film deposition, mixing a reactant with the substrate to deposit a titanium-zirconium-yttrium alloy film on the surface of the substrate; S3. Heat activation: Place the mixed substrate and reactant in a constant temperature environment of 200 °C and maintain for 30 min to activate the film performance. Further, step S1 includes the following steps: S11. Select a substrate: Select a suitable substrate from various materials, where the substrate material is stainless steel, kovar, silicon, germanium, or ceramic. S12. Clean the substrate: Perform high-pressure cleaning on the surface of the substrate and then dry it.

[0016] Further, in step S3, the atomic ratio of titanium to zirconium in the mixed reactant is from 1:2 to 2:1, and the atomic ratio of titanium plus zirconium to yttrium is from 20:1 to 10:1.

[0017] Further, in step S3, the atomic ratio of titanium and zirconium in the mixed reactant is 1:1, and the atomic ratio of titanium plus zirconium to yttrium is 10:1.

[0018] Further, in step S3, place the mixed substrate and reactant in a constant temperature environment of 250 °C and maintain for 30 min to activate the film performance.

[0019] Further, in step S3, place the mixed substrate and reactant in a constant temperature environment of 300 °C and maintain for 30 min to activate the film performance.

[0020] The beneficial effects of the present invention are as follows: The present invention can not only effectively reduce the activation temperature of the film, but also improve the quality of the finished product. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0022] Figure 1 It is a schematic diagram of the overall structure of a low-temperature activated getter film provided by the present invention.

[0023] Figure 2 It is a schematic diagram of the process flow of a production method of a low-temperature activated getter film provided by the present invention.

[0024] Figure 3 It is a schematic diagram of the substrate preparation process flow of a production method of a low-temperature activated getter film provided by the present invention.

[0025] Explanation of the reference numerals: 1. Getter layer; 2. Crystal grains. Detailed Implementation Modes

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Embodiment

[0027] Referring to Figure 1 In this embodiment, a low-temperature-activated getter film includes a getter layer 1. The material of the getter layer 1 is a titanium-zirconium-yttrium alloy film, which is formed by depositing titanium atoms, zirconium atoms, and a certain amount of yttrium atoms on the surface of a substrate. The substrate of the getter layer 1 can be stainless steel, kovar, silicon, germanium, or ceramic. The getter layer 1 is prepared by a magnetron sputtering process. The film thickness of the getter layer 1 is from 0.1 micrometer to 10 micrometers. The getter layer 1 includes grains 2, and the size of the grains 2 is from 5 to 300 nanometers.

[0028] Referring to Figure 2 A production method of a low-temperature-activated large-capacity getter film includes the following specific steps: S1. Substrate preparation: Prepare a substrate for the reaction; S2. Film deposition: Mix the reactants with the substrate to deposit a titanium-zirconium-yttrium alloy film on the surface of the substrate; S3. Heating activation: Place the mixed substrate and reactants in a constant-temperature environment of 200 °C and keep it for 30 min to activate the film performance.

[0029] Referring to Figure 2 In a preferred implementation mode, in S2, the required materials for film deposition are as follows: titanium atoms, zirconium atoms, yttrium atoms, and the titanium, zirconium, and yttrium atoms are mixed. The atomic ratio of titanium to zirconium in the mixed reactant is from 1:2 to 2:1, and the atomic ratio of titanium plus zirconium to yttrium is from 20:1 to 10:1; preferably, in S3, the more preferred ratio of the atomic percentages of titanium and zirconium in the mixed reactant is 1:1; the more preferred atomic ratio of titanium plus zirconium to yttrium is 10:1.

[0030] Referring to Figure 3 In step S1, the substrate preparation includes the following specific steps: S11. Select a substrate: Select a suitable substrate from various materials, and the material of the substrate can be stainless steel, kovar, silicon, germanium, or ceramic; S12. Clean the substrate: Perform high-pressure cleaning on the surface of the substrate and dry it.

[0031] In this embodiment, a titanium-zirconium-yttrium target material is prepared by powder metallurgy, wherein the atomic ratio of titanium-zirconium-yttrium is 10:10:1; Using a 1cm*1cm square single-sided polished single crystal silicon as the substrate, the titanium zirconium yttrium target material of this embodiment, and the process of producing getter films, magnetron sputtering was performed for 3 hours to obtain a getter film with a grain size of about tens of nanometers and a thickness of about 2 microns. This is sample 1. Example

[0032] The titanium-zirconium-yttrium target material is prepared by powder metallurgy, wherein the atomic ratio of titanium-zirconium-yttrium is 10:10:1.

[0033] Using a 1cm*1cm square single-sided polished single crystal silicon as the substrate, the titanium zirconium yttrium target material of this embodiment, and the process of producing getter films, magnetron sputtering was performed for 6 hours to obtain a getter film with a grain size of about tens of nanometers and a thickness of about 4 microns. This is sample 2. Example

[0034] The titanium-zirconium-yttrium target material is prepared by powder metallurgy, wherein the atomic ratio of titanium-zirconium-yttrium is 10:5:1.

[0035] Using a 1cm*1cm square single-sided polished single-crystalline silicon as the substrate, the titanium zirconium yttrium target material of this embodiment, and the process of producing getter films, magnetron sputtering was performed for 3 hours to obtain a getter film with a grain size of about tens of nanometers and a thickness of about 2 microns. This is sample 3. Example

[0036] The titanium-zirconium-yttrium target material is prepared by powder metallurgy, wherein the atomic ratio of titanium-zirconium-yttrium is 5:10:1.

[0037] Using a 1cm*1cm square single-sided polished single-crystalline silicon as the substrate, the titanium zirconium yttrium target material of this embodiment, and the process of producing getter films, magnetron sputtering was performed for 3 hours to obtain a getter film with a grain size of about tens of nanometers and a thickness of about 2 microns. This is sample 4. Example

[0038] The titanium-zirconium-yttrium target material is prepared by powder metallurgy, wherein the atomic ratio of titanium-zirconium-yttrium is 5:5:1.

[0039] Using a 1cm*1cm square single-sided polished single-crystalline silicon as the substrate and the titanium zirconium yttrium of this embodiment as the target material, magnetron sputtering was performed for 3 hours using the process commonly used to produce getter films to obtain a getter film with a grain size of about tens of nanometers and a thickness of about 2 microns. This is sample 5. Example

[0040] This example is a prior art for comparison. A titanium-zirconium target material is prepared by powder metallurgy, wherein the atomic ratio of titanium to zirconium is 3:2.

[0041] Using a 1cm*1cm square single-sided polished single-crystalline silicon as the substrate and the titanium-zirconium target material of this embodiment, magnetron sputtering was performed for 2.5 hours using the process for producing getter films commonly used to obtain a getter film with a grain size of about tens of nanometers and a thickness of about 2 microns. This is sample 6. Example

[0042] In this example, carbon monoxide is used as the test gas, and the constant volume method is used to test the inhalation capacity of samples 1 to 6. Samples 1 to 6 are tested in sequence according to the following steps: First, the sample is sealed in a vacuum chamber with a fixed volume, and then the test system is baked and exhausted. After the system cools down, it is activated at a certain temperature and time. After the sample cools to room temperature, a known amount of carbon monoxide is filled into the system. After the pressure of the system is balanced, the residual pressure inside the system is measured. The difference between the amount filled into the system and the residual amount inside the system is the carbon monoxide absorption capacity of this test.

[0043] In this embodiment, no effective gas absorption phenomenon was observed for sample 6 under the activation condition of 200° C.*2 h.

[0044] From the comparison data of sample 1 and sample 6, it can be seen that after adding about 10% of yttrium, the activation temperature of the getter film can be reduced by about 50°C.

[0045] From the comparison data of sample 1 and sample 2, it can be seen that the carbon monoxide absorption capacity of the getter film is basically proportional to the film thickness.

[0046] From the comparison data of sample 1 and sample 3, sample 4, sample 5, and sample 6, it can be seen that under the condition of basically the same film thickness, the air-absorbing film of the present invention can be activated in a shorter time at 200°C compared with the prior art, and can obtain a higher air absorption capacity than the prior art by activating it at 250°C for 30 minutes. Example

[0047] In this example, hydrogen is used as the test gas, and the constant pressure method is used to test the inhalation rate of another group of samples 1 to 6 that have not been tested. Test samples 1 to 6 in turn according to the following steps: First, the sample is sealed in the constant pressure method air intake performance test bench, and then the test system is baked and exhausted. After the system cools down, it is activated at a certain temperature and time. After the sample cools to room temperature, hydrogen is filled into the sample chamber at a constant pressure of 4E-4Pa through a known flow guide. According to the pressure difference at both ends of the known flow guide, the initial air intake rate of the air intake film is calculated.

[0048] The test results of the hydrogen intake rate are basically the same as those of the carbon monoxide intake capacity test. The intake film of the present invention shows that it can be activated in a shorter time at 200°C. When activated at 250°C for 30 minutes, a higher intake capacity than the prior art can be obtained. However, the thickness of the film has no obvious effect on the hydrogen absorption rate under high vacuum conditions. This is because it is relatively difficult for hydrogen to diffuse into the interior of the intake film under high vacuum conditions, and the internal surface area of the intake film does not fully participate in the intake process.

[0049] Working principle: During use, by setting an additive in the intake layer, and the material is a titanium-zirconium-yttrium alloy film. The preparation process of the titanium-zirconium-yttrium alloy film is to mix titanium atoms, zirconium atoms and yttrium atoms and deposit them on a substrate. Thereby, the activation temperature of the film can be reduced, and the activation conditions can be as low as 200°C for 30 minutes. When activated in a low-temperature environment, it can have good intake capacity for both carbon monoxide and hydrogen, thus ensuring the quality of the finished product.

[0050] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A low temperature activated getter film, characterized in that: include: An air getter layer (1), wherein the material of the air getter layer (1) is a titanium-zirconium-yttrium alloy film, wherein the titanium-zirconium-yttrium alloy film is a film produced by depositing titanium atoms, zirconium atoms and a set amount of yttrium atoms on the surface of a substrate; the substrate of the air getter layer (1) is stainless steel, Kovar, silicon, germanium or ceramic; The getter layer (1) is prepared by a magnetron sputtering process, the film thickness of the getter layer (1) is 0.1 micrometers to 10 micrometers, the getter layer (1) comprises crystal grains (2), and the size of the crystal grains (2) is 5 to 300 nanometers.

2. A low temperature activated getter film according to claim 1, characterized in that: The film thickness of the air absorption layer (1) is 2 micrometers to 4 micrometers.

3. A low temperature activated getter film according to claim 1, characterized in that: The size of the grains (2) is 10 nanometers.

4. A method for producing a low temperature activated getter film according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, substrate preparation, preparing the substrate for reaction; S2, thin film deposition, mixing the reactant with the substrate to deposit a titanium zirconium yttrium alloy thin film on the substrate surface; S3, heating activation, placing the mixed substrate and reactant in a constant temperature environment of 200°C for 30 minutes to activate the film properties.

5. A method for producing a low temperature activated getter film according to claim 4, characterized in that: The step S1 comprises the following steps: S11, selecting a substrate, selecting a suitable substrate from a variety of materials, wherein the material of the substrate is stainless steel, Kovar, silicon, germanium or ceramic; S12, cleaning the substrate, high-pressure cleaning the surface of the substrate and drying it.

6. A method for producing a low temperature activated getter film according to claim 4, characterized in that: In step S3, the atomic ratio of titanium to zirconium in the mixed reactants is from 1:2 to 2:1, and the atomic ratio of titanium plus zirconium to yttrium is from 20:1 to 10:

1.

7. A method for producing a low temperature activated getter film according to claim 4, characterized in that: In the step S3, the atomic ratio of titanium to zirconium in the mixed reactants is 1:1, and the atomic ratio of titanium plus zirconium to yttrium is 10:

1.

8. A method for producing a low temperature activated getter film according to claim 4, characterized in that: In the step S3, the mixed substrate and reactant are placed in a constant temperature environment of 250° C. for 30 minutes to activate the film properties.

9. A method for producing a low temperature activated getter film according to claim 4, characterized in that: In step S3, the mixed substrate and reactant are placed in a constant temperature environment of 300° C. for 30 minutes to activate the film properties.

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