JP5178604B2 - Gas adsorption element forming body, gas adsorption element mounting method, and vacuum package - Google Patents

Description

  The present invention relates to an element for gas adsorption for vacuum-sealing devices such as an acceleration sensor, an infrared sensor, a gyro sensor, and a crystal resonator, a gas adsorption element forming body used for forming the element, a mounting method, and The present invention relates to a vacuum package on which a gas adsorption element is mounted.

  In a package in which devices such as an acceleration sensor, an infrared sensor, a gyro sensor, and a crystal resonator are sealed, it is required to reduce the internal pressure inside the package in order to improve device characteristics. As this method, as disclosed in Patent Document 1, it is known to arrange a getter in a package.

  The getter is made of, for example, a metal such as Ti, Zr, V, or Fe, or an alloy thereof, and adsorbs many gases excluding an inert gas by performing a heat treatment called activation in a vacuum. Has an effect.

  In the atmosphere, the surface of the getter is covered with gaseous adsorbed molecules, so no further adsorption reaction takes place. However, when the getter is heated in a vacuum (for example, 400 ° C. or more), the adsorbed gas is diffused into the getter, the surface is activated, and, for example, the adsorption action is exhibited even near room temperature.

  By disposing the getter in the package, gas molecules that cannot be completely removed by the vacuum pump can be adsorbed to the getter material, and the internal pressure in the package can be further reduced.

JP 2003-4524 A

  For heating for activation, energization heating by a heater such as a nichrome wire, heat at the time of package sealing, electromagnetic heating, or the like is used. However, a getter with a built-in heater for energization heating is expensive, and requires a space for arranging electrodes and heaters for energization, which makes it difficult to reduce the size.

  In addition, for example, infrared sensor chips and reflective coatings for window materials have a problem that they are vulnerable to heat. Heating at a high temperature for activation may damage devices and packages that are sensitive to such heat, and may cause poor characteristics.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a formed body for forming a gas adsorption element capable of obtaining an activated getter surface without heating. To do. Another object of the present invention is to provide a method for mounting a gas adsorbing element using the gas adsorbing element forming body and a vacuum package on which the gas adsorbing element is mounted.

The gas adsorbing element forming body of the present invention includes a getter metal body containing a getter material, and a breaker that breaks the getter metal body to expose a new surface. The breaker includes the getter metal The getter metal body includes a first member and a second member joined to a body, and at least one of the first member and the second member is peeled off from the getter metal body. It tries to break .

  The method for mounting a gas adsorbing element according to the present invention includes the step of disposing the gas adsorbing element forming body according to the present invention in a container main body, the step of evacuating the container main body, and the breaker. A step of breaking the metal body, and a step of hermetically sealing the container body.

Package of the present invention, a container body for use in evacuating the inside to a vacuum, the disposed in the container body, and a new surface exposed by the getter metal body is broken by the breaking means including a getter material fracture surface I A gas adsorbing element , wherein the breaking means includes a first member and a second member joined to the getter metal body, wherein the first member and the second member The getter metal body is broken by peeling off at least one of the getter metal bodies .

  The gas adsorbing element forming body of the present invention, in a getter metal body containing a getter material, breaks the metal body using a breaking means so as to expose a new surface. A clean metal surface can be obtained. In other words, an activated getter surface can be obtained without heating. Since heating is not required, there is no need for a configuration such as a heater or an electrode necessary for heating, which contributes to low cost and downsizing of the gas adsorbing element and a package in which the gas adsorbing element is mounted. In addition, adverse effects on the device and package due to heating can be suppressed.

(A) is typical sectional drawing which shows the gas adsorption element formation body which concerns on 1st Embodiment of this invention, (b) is typical sectional drawing which shows the state which mounted this gas adsorption element formation body FIG. It is a typical sectional view showing a package carrying a gas adsorption element concerning a 1st embodiment of the present invention. (A)-(c) is typical structural drawing which shows the process which forms the gas adsorption element formation body and gas adsorption element which concern on 1st Embodiment of this invention from the sintered compact of a metal particle. (A) is typical sectional drawing which shows the gas adsorption element formation body which concerns on 2nd Embodiment of this invention, (b) is typical sectional drawing which shows the state which mounted this gas adsorption element formation body FIG. (A) is typical sectional drawing which shows the gas adsorption element formation body which concerns on the modification of 2nd Embodiment of this invention, (b) is a model which forms a gas adsorption element from this gas adsorption element formation body FIG. 2C is a schematic cross-sectional view showing a package in which such a gas adsorption element is mounted.

  Hereinafter, examples of embodiments of the present invention will be described in detail with reference to the drawings.

  However, in the drawings referred to below, for the convenience of explanation, among the constituent members of one embodiment of the present invention, only the main members necessary for explaining the present invention are shown in a simplified manner. Therefore, the gas adsorbing element, the gas adsorbing element forming body, and the vacuum package according to the present invention may include arbitrary constituent members that are not shown in the drawings referred to in this specification. Moreover, the dimension of the member in each figure does not faithfully represent the dimension of the actual component member, the dimension ratio of each member, or the like.

<First Embodiment>
Fig.1 (a) is typical sectional drawing which shows the gas adsorption element formation body which concerns on 1st Embodiment of this invention, (b) is typical which shows the state which mounted this gas adsorption element formation body FIG. FIG. 2 is a schematic cross-sectional view showing a package on which the gas adsorption element according to the first embodiment of the present invention is mounted.

  In this embodiment, 1 is a first member made of a thin metal plate, 2 is a second member made of a thin metal plate, 3 is a getter metal body containing a getter material, 3a is a gas adsorption element, 4 is a package, 4a is a container A package base portion functioning as a main body, 4b is a lid, 5 is a fixing portion, 6 is a connecting material, 7 is a device, and 8 is a sealing material.

  FIG. 1A shows a gas adsorbing element forming body according to this embodiment. A getter metal body 3 is fixed and sandwiched between a thin metal plate 1 as a first member and a thin metal plate 2 as a second member. In the present embodiment, the thin metal plates 1 and 2 of the first and second members function as breaking means for breaking the getter metal body and exposing a new surface.

  Specifically, the gas adsorption effect of the getter metal body 3 is that the metal thin plate 1 and the metal thin plate 2 are peeled off from the getter metal body 3 to break the getter metal body 3 and expose a new fracture surface. It is expressed by. As a result, a new fracture surface that is not contaminated (no gas is adsorbed) of the getter metal body 3 is exposed, so that the gas adsorbing element forming body functions as a gas adsorbing element without heating. .

  In the present specification, the “gas adsorbing element forming body” does not function as a gas adsorbing element in a state before breaking, but has a function of gas adsorbing by breaking the getter metal body as described above. It refers to what can be expressed.

  FIG. 1B shows a state where the gas adsorbing element forming body according to the present embodiment shown in FIG. 1A is mounted on the package base 4a. The package base portion 4a is provided with a fixing portion 5 made of a metallized layer or the like, and the metal thin plate 1 is fixed to the fixing portion 5 via a connecting material 6 such as a brazing material. Here, as shown by the arrows in the figure, the thin metal plate 2 is peeled off and the getter metal body 3 is broken, whereby the gas adsorbing element forming body can function as a gas adsorbing element.

  FIG. 2 shows an example in which a vacuum package is configured by the package 4 on which the gas adsorption element 3a according to the present embodiment is mounted. The package 4 includes a gas adsorbing element 3 a formed by breaking the getter metal body 3 together with a device 7 such as an infrared sensor. The getter metal body 3 is broken in a vacuum, and thereafter, the lid 4b is hermetically sealed with the sealing material 8 in a state where the inside of the package base 4a is kept in a vacuum. Thus, the vacuum package according to the present invention can be obtained.

  As described above, the gas adsorption element 3a according to the present embodiment can obtain a clean metal surface, that is, an activated getter surface, without performing heating. Therefore, there is no need for a configuration such as a heater or an electrode necessary for heating, which contributes to low cost and downsizing of the gas adsorption element 3a itself and the package 4 on which the gas adsorption element 3a is mounted. In addition, adverse effects on the device 7 and the package 4 due to heating can be suppressed.

  Hereinafter, components according to the present embodiment will be described in detail with reference to the accompanying drawings.

(Getter metal body)
The getter metal body 3 functions as a gas adsorbent in the package. The getter metal body 3 includes a transition metal selected from at least one element of Ba, Zr, Ti, Ta, V, Al, Fe, Ni, Nb and Mn. Not only a metal simple substance but an alloy may be sufficient. For example, an alloy between these metals or an alloy between these metals and one or more elements selected from Cr, Mn, Fe, Co, Ni, Al, Y, La, and rare earths, for example, Binary alloys Ti-V, Zr-V, Zr-Fe and Zr-Ni, ternary alloys Zr-Mn-Fe or Zr-V-Fe or alloys with further components may be used.

  These metals are chemically active, and exhibit a gas adsorption action by exposing a new fracture surface. It is possible to perform evacuation using this action.

  In the present embodiment, the getter metal body 3 is provided in a state of being sandwiched and fixed between the metal thin plates 1 and 2 that are the first and second members constituting the breaking means.

  The getter metal body 3 sandwiched between the metal thin plates 1 and 2 can be formed by using a thin film forming method such as sputtering, but can be easily formed with a different thickness and sintered. Since it is easy to break and the state of the fracture surface can be controlled by temperature or the like, it is desirable to form a sintered body obtained by sintering metal particles of a getter material containing these metals and alloys. In addition, when the getter metal body 3 is comprised with a sintered compact, in order to make it fracture easily, it is desirable to make a porosity into 50% or less. For the same reason, the thickness is desirably 100 μm or less. Furthermore, in order to obtain a fracture surface having a sufficient surface area when fractured, it is desirable that the porosity be 10% or more. For the same reason, the thickness is desirably 10 μm or more.

  3A to 3C show the concept of a process for forming a gas adsorbing element forming body and a gas adsorbing element according to this embodiment from a sintered body of metal particles. In FIG. 3A, a paste including metal particles 9 including a getter material is disposed on the metal thin plates 1 and 2. In FIG. 3B, the metal particles 9 are heated to form a sintered body in which metal bonds are formed with each other, and the getter metal body 3 according to the gas adsorption element forming body of the present invention is formed. The getter metal body 3 which is a sintered body is in a state of being fixed to the metal thin plates 1 and 2, but has an appropriate porosity and can be broken by applying a predetermined external force. Therefore, as shown in FIG. 3 (c), the metal thin plates 1 and 2 are peeled away from each other, whereby the getter metal body 3 is divided to form a new fracture surface, and the gas adsorbing element of the present invention is formed. Is done.

  Further, when the getter metal body 3 is formed of a sintered body, it is desirable to use an ultrafine particle material in which the metal particles 9 including the getter material can be sintered at 200 ° C. or less. The reason is that low-temperature sintering is possible and damage to the first and second members (in this embodiment, the metal thin plates 1 and 2) constituting the breaking means can be suppressed. .

  As an example of such an ultrafine particle material, Ti ultrafine particles having a diameter of about 1 nm to 1 μm are known. These ultrafine metal powders are extremely active on the surface and easily oxidize in the air alone, so they are usually kneaded in a paste containing an organic solvent or binder, and the surface is coated with an organic solvent. Will be handled.

  A paste containing such ultrafine metal powder is applied between the metal thin plates 1 and 2 with an appropriate thickness, and then sufficiently dried. As a result, the organic solvent on the surface of the metal ultrafine particles is scattered and the metal ultrafine particles are sintered at a low temperature of 150 to 200 ° C. to form a metal bond with each other.

(Breaking means)
In this embodiment, the example which comprised the 1st and 2nd member joined with respect to the getter metal body 3 as the thin metal plates 1 and 2 as a fracture | rupture means, respectively is shown. These metal thin plates 1 and 2 can use well-known metals, such as copper, stainless steel, nichrome, for example. Further, the thickness of the thin metal plates 1 and 2 is desirably 10 μm or more in order to withstand the stress of peeling. Moreover, since moderate flexibility is required to perform the peeling operation, the thickness is desirably 100 μm or less.

  Further, in order to obtain a good adhesion between the metal thin plate and the getter metal body 3, the oxide film on the surface of the metal thin plate is removed beforehand by acid treatment or the like, and the surface roughness is set to Rmax 0. It is effective to set it to 1 μm or more.

  In order to make the breaking means function, either the thin metal plate 1 or the thin metal plate 2, which is the first and second members, may be peeled off from the getter metal body 3. Since the getter metal body 3 needs to be broken in a vacuum, the package 4 is actually held in a vacuum apparatus, and any of the thin metal plates 1 and 2 is used by using a jig or a dedicated device from the outside. What is necessary is just to peel off from the getter metal body 3.

  The first and second members are not limited to a metal material such as a metal thin plate, and a material such as ceramic may be used. Furthermore, when using this gas adsorption element for the use of the device which can be heated, you may use the heater material which can carry out the heating of either of these 1st and 2nd members. For example, the metal thin plate itself may be configured using a heating resistor material such as nichrome, or a heating resistor such as a thin film heater or a thick film heater formed on the first and second members. It may be used. By using such a heater material, when the gas adsorption function of the getter metal body 3 is lowered, the heat treatment for activation can be performed to restore the gas adsorption function.

(package)
The package 4 is provided in such a manner that a lid 4b is airtightly bonded to a package base 4a that is a container body. The package base portion 4a has a concave portion on the inside, and a device 7 to be described later is disposed in the concave portion, and the concave portion is sealed with a lid 4b so that the package base portion 4a can be used as the package 4. .

Package base portion 4a, for example, aluminum oxide _(Al 2 _{O 3)} sintered material, mullite _{(3Al 2 O 3 · 2SiO 2} ) sintered material, silicon carbide (SiC) sintered material, aluminum nitride (AlN ) Quality sintered body, silicon nitride (Si ₃ N ₄ ) quality sintered body and ceramic materials such as glass ceramics, high heat-resistant resin materials such as polyimide, SUS, Fe—Ni—Co alloy, Fe—Ni alloy Or any other metal material such as oxygen-free copper, Al, or an Al alloy.

  The package base portion 4a is preferably thin in order to reduce the size and height of the package 4. However, in order to maintain the strength, the bending strength, which is mechanical strength, is 200 MPa or more. Is preferable. By setting the bending strength to 200 MPa or more, the mechanical strength of the package base portion 4a can be suitably maintained.

  Further, a device 7 that suitably exhibits characteristics in a vacuum, such as an acceleration sensor, an infrared sensor, a gyro sensor, and a crystal resonator, is disposed in the recess of the package base 4a.

Further, a gas adsorbing element 3a configured by exposing a surface obtained by breaking the getter metal body 3 is provided in the recess of the package base 4a. Note that the gas molecules present in the package 4 to be adsorbed by the gas adsorption element 3a are the package 4 such as the package base 4a, the lid 4b, and the sealing material 8 when the package 4 is manufactured and used. Examples of the gas generated from the constituent members, and gases such as N ₂ , O ₂ , CO ₂ , and H ₂ O that are mixed during the production or adsorbed on the surface.

  In sealing the package 4, the package base 4 a and the lid 4 b can be joined using a conventionally known joining method. That is, there are a method of joining with solder or a metal brazing material, a method of seam weld, electron beam, laser or the like. As the sealing material 8, a material mainly composed of Au, Ag, Zn, Sn, or an alloy thereof can be used.

Second Embodiment
Next, a second embodiment of the present invention will be described. Differences from the first embodiment will be mainly described, components that are the same as those in the first embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

  FIG. 4A is a schematic cross-sectional view showing a gas adsorbing element forming body according to the second embodiment of the present invention, and FIG. 4B is a schematic showing a state in which the gas adsorbing element forming body is mounted. FIG.

  The second embodiment is different from the first embodiment described above in that the silicon substrate 11 is used as the first member constituting the breaking means and the thin metal plate 12 is used as the second member. As described above, the getter metal body 13 is preferably formed by sintering metal particles containing a getter material. Specifically, the paste containing the metal particles is applied to a predetermined position of the silicon substrate 11 with an appropriate thickness, and then sintered with the metal thin plate 12 attached to form a sintered body of the getter metal body 13. To do. Thereby, the gas adsorption element formation object concerning a 2nd embodiment can be formed.

  After that, if the silicon substrate 11 is disposed in the recess of the package base portion 14a and the getter metal body 13 is broken by peeling the thin metal plate 12 from the getter metal body 13 as shown in the figure, The gas adsorption element according to the present embodiment can be formed.

  According to this embodiment, since the gas adsorption element can be provided at an arbitrary position of the silicon substrate 11, the degree of freedom of layout in the package is increased, which contributes to downsizing. Further, the gas adsorption element can be arranged at an effective position. For example, a high vacuum degree in the vicinity of the device can be maintained by forming a MEMS device (not shown) in the silicon substrate 11 in advance and providing a gas adsorbing element in the immediate vicinity thereof. Thereby, the characteristic of the device used by a high vacuum can be exhibited more reliably.

  Further, when the getter metal body 13 is manufactured after a device is previously formed on a silicon substrate, the getter metal body 13 is formed using the ultrafine particle material that can be sintered at 200 ° C. or lower as described in the first embodiment. It is desirable to configure. This is because the temperature for producing the getter metal body 13 is low, so that damage to the device can be suppressed.

<Modification of Second Embodiment>
Next, a modification of the second embodiment will be described with reference to FIG. In the above description of the second embodiment, the silicon substrate, which is the first member, is disposed in the package. However, in the modification described here, the first member (for example, the silicon substrate) is used as the lid of the package. The point of using as a body is different.

  Fig.5 (a) is typical sectional drawing which shows the gas adsorption element formation body which concerns on the modification of 2nd Embodiment of this invention, FIG.5 (b) is a gas adsorption element from this gas adsorption element formation body. FIG. 5C is a schematic cross-sectional view showing a package on which such a gas adsorbing element is mounted.

  This modification is different from the second embodiment in that, as shown in FIG. 5C, the getter metal body 23 is broken so that the silicon substrate 21 as the first member becomes the lid 24b of the package. The side of the gas adsorption element 23a obtained in this manner is the inside of the lid 24b, and is mounted on the package base 24a via the sealing material 28. A predetermined device 27 can be mounted on the package base 24a. According to this configuration, since the first member constituting the breaking means is also used as the lid 24b, the gas adsorbing element 23a is also provided on the lid 24b side, which contributes to downsizing of the package.

  Further, since silicon is a material that easily transmits infrared rays, when it is used as the lid 24b, it functions not only as a lid for hermetic sealing but also as a window material for infrared. Become. Therefore, as the device 27 disposed inside the package 24, the infrared sensor chip can be sealed and used suitably.

  In the example of the present embodiment, as an example of the first member constituting the breaking means, an example using silicon, which is a material excellent in infrared transmittance, has been described, but in addition, germanium, zinc sulfide, fluoride Magnesium or the like is also a material having good infrared transmittance, and can be used as the first member constituting the breaking means. However, it is desirable to use silicon for the hermetic sealing lid 24b of the vacuum package in order to maintain a high degree of vacuum.

  When a silicon material is used as an infrared window material, an infrared antireflection coating film or a band-pass filter film for imparting selectivity to the transmitted infrared wavelength is formed on the surface of the window material. Since these films and infrared sensor chips are susceptible to heat, when a conventional getter is used, there is a risk of damage caused by heating to activate the surface. In the gas adsorption element of the present embodiment, an activated getter surface can be obtained without heating, so that adverse effects due to heating can be suppressed.

  The present invention can be realized by the configuration and method described above. The present invention is not limited to the above embodiment, and various changes and improvements can be made without departing from the gist of the present invention.

  For example, in the description of the first embodiment described above, an example is described in which the getter metal body 3 that is a gas adsorbing element forming body is evacuated after being disposed in the recess of the package base body portion 4a. However, the present invention is not limited to this. Alternatively, after evacuation, the getter metal body 3 may be disposed in the recess of the package base 4a, and then the getter metal body 3 may be broken. It is only necessary to prevent the exposed fracture surface of the gas adsorbing element 3a from coming into contact with the gas after the fracture until the package base 4a is hermetically sealed.

  Furthermore, in the description of the second embodiment described above, an example in which a silicon substrate is used as the first member has been described. However, the present invention is not limited to this, and a substrate made of another material may be used. Further, the getter metal body 13 may be provided directly on the package base 4a without using a substrate or a thin metal plate as the first member. In this case, the package base portion 4a functions as a first member that is a breaking means.

  In the above description of the second embodiment, an example in which the package base portion 4a has a recess and the device or the gas adsorbing element according to the present invention is disposed in the recess has been described. Instead of the device, the device may be provided on the side of the lid of the package.

1. Metal thin plate (first member in the first embodiment)
2. Metal thin plate (second member in the first embodiment)
3 ... Getter metal body 3a ... Gas adsorption element 4 ... Package 4a ... Package base (container body)
4b ··· Lid 5 ··· Fixing portion 6 ··· Connection material 7 ··· Device 8 ··· Sealing material 9 ··· Metal particles 11 · .... Silicon substrate (first member in the second embodiment)
12... Metal thin plate (second member in the second embodiment)
13... Getter metal body 21... Silicon substrate (first member in the modification of the second embodiment)
22 ... Metal thin plate (second member in a modification of the second embodiment)
23 ... Getter metal body 23a ... Gas adsorption element 24 ... Package 24a ... Package base (container body)
24b: Lid 27: Device (Infrared sensor)
28 …… Encapsulant

Claims (10)

A getter metal body including a getter material;
Breaking means for breaking the getter metal body to expose a new surface , and
The breaking means includes a first member and a second member joined to the getter metal body, and peels at least one of the first member and the second member from the getter metal body. A gas adsorbing element forming body in which the getter metal body is broken .   The gas adsorption element formation object according to claim 1, wherein the getter metal body is a sintered body obtained by sintering metal particles containing a getter material.   The gas adsorption element formation object according to claim 2 whose metal particles containing said getter material are ultrafine particle materials which can be sintered at 200 ° C or less.   The getter material includes a transition metal selected from at least one element of Ba, Zr, Ti, Ta, V, Al, Fe, Ni, Nb, and Mn. The gas adsorbing element forming body according to the item. The gas adsorbing element forming body according to any one of claims 1 to 4, wherein at least one of the first member and the second member is a thin metal plate. The first member is made of a material used as a lid of a vacuum package;
The gas adsorbing element forming body according to any one of claims 1 to 5, wherein the second member is peeled off from the getter metal body. The gas adsorbing element forming body according to claim 6 , wherein the first member is made of a material that transmits infrared rays. The gas adsorption element formation object according to any one of claims 1 to 5 in which any one of said 1st member and said 2nd member is heater material which can carry out energization heating. Arranging the gas adsorbing element forming body according to any one of claims 1 to 8 in a container body;
Evacuating the container body; and
Breaking the getter metal body using the breaking means;
And a step of hermetically sealing the container main body. A package comprising: a container body that is used by evacuating the inside thereof; and a lid that hermetically seals the container body;
A device disposed within the container body;
Wherein disposed in the container body, provided with a gas adsorbing element that Do new plane fracture surface exposed by breaking the breaking means a getter metal comprising a getter material,
The breaking means includes a first member and a second member joined to the getter metal body, and peels at least one of the first member and the second member from the getter metal body. A vacuum package in which the getter metal body is broken .

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