Lid, device, and method for manufacturing device

Abstract

This lid is mounted on a base 5 on which an electronic component element is mounted in a mounting region 4. The lid includes: a lid body 8 made of a metal foil; and a sealing material which is provided in at least a part of a region of the lid body 8 to be joined with the base 5 and contains a metal having a melting point of 265°C or lower.

Description

Lid, device, and method for manufacturing device

[0001] The present invention relates to a device in which an electronic component element is mounted and sealed, a lid used for sealing the device, and a method for manufacturing the device.

[0002] Piezoelectric devices, which output signals of a specific frequency, are equipped with a piezoelectric vibration element. For example, the piezoelectric vibration element is a quartz crystal vibration element. Since the characteristics of a quartz crystal vibration element change depending on the surrounding gas composition and environmental factors such as temperature and humidity, piezoelectric devices are configured with the quartz crystal vibration element sealed in a package. In particular, quartz crystal vibration elements are sometimes vacuum sealed because they generate air resistance when vibrating.

[0003] For example, as disclosed in Patent Document 1, a device (piezoelectric oscillator) has an internal space hermetically sealed to prevent deterioration of the characteristics of a quartz crystal vibration element (piezoelectric vibration element) mounted therein. The device here refers to, for example, a device whose main body housing is a package (container) made up of a base and a lid, and whose internal space contains electronic component elements such as semiconductor elements and quartz crystal vibration elements.

[0004] Japanese Patent Application Laid-Open No. 2009-267866

[0005] However, the base may warp due to heating, such as during ceramic firing or when bonding the base and lid (lid body) together for sealing. As a result, the gap between the base and lid (lid body) may be approximately 0.005 mm to 0.01 mm during sealing. Furthermore, heating, such as reflow, may melt the sealing material, destroying the seal. Since piezoelectric devices must maintain strength, heat resistance, airtightness, and weather resistance, it is necessary to completely seal the gap between the base and lid (lid body) with a sealing material.

[0006] An object of the present invention is to ensure airtightness easily and simply.

[0007] In order to achieve the above-mentioned object, a lid according to one embodiment of the present invention is a lid that is attached to a base on which an electronic component element is mounted in a mounting area, and comprises a lid body made of metal foil, and a sealing material containing a metal having a melting point of 265°C or less that is provided in at least a portion of the joining area of ​​the lid body with the base.

[0008] Furthermore, a lid according to one embodiment of the present invention is a lid that is attached to a base on which an electronic component element is mounted in a mounting area, and comprises a lid body made of metal foil, and a sealing material containing a metal having a melting point of 265°C or less that is provided in at least a portion of the joining area of ​​the lid body with the base, wherein the lid body is in the form of a sheet of a size that can seal a plurality of the bases, and the sealing material is provided in at least the joining area of ​​the lid body with each of the bases.

[0009] A device according to one embodiment of the present invention comprises a base having a mounting area, an electronic component element mounted in the mounting area of ​​the base, a lid body joined to the base so as to cover the mounting area, and a sealing material joining the base and the lid body, wherein the electronic component element is sealed within the storage area by the base and the lid body, the lid body is a metal foil, and at least a portion of the sealing material contains a metal having a melting point of 265°C or less.

[0010] With this configuration, since the lid body is made of metal foil, the lid body can be deformed along the warp of the warped base and then bonded to the base in that state. Furthermore, since the lid body is bonded along the base, the gap between the lid body and the base is prevented from becoming large. This prevents the need for a large amount of sealing material to fill the gap between the lid body and the base. In particular, if the sealing material contains gold, the amount of gold required can be reduced.

[0011] Furthermore, because the sealing material is made of a metal with a melting point of 265°C or less (260°C ± 5°C or less), airtight sealing can be performed at low temperatures, and gas generation from the conductive adhesive that fixes the electronic component elements can be suppressed. Furthermore, because the sealing material is made of metal, moisture is prevented from entering the housing area compared to when sealing is done with resin, and weather resistance can be ensured.

[0012] As a result, airtightness, heat resistance, and weather resistance can be ensured with a simple configuration.

[0013] When the lid body is sheet-shaped, i.e., large enough to seal multiple bases, the sheet-shaped lid body (sheet) can be placed over multiple bases at once to bond the bases and then separated into individual bases. Therefore, by combining the sheet-shaped lid body with a base assembly (sheet-shaped bases) in which multiple bases are integrally molded, multiple devices can be manufactured at once. This allows for efficient device manufacturing.

[0014] The lid body preferably has a thickness of 0.003 mm or more and 0.03 mm or less.

[0015] Since the thickness of the lid body is 0.003 mm or more and 0.03 mm or less, the lid body can be easily deformed to follow the warp of the base and can be joined to the base in that state. As a result, airtightness, heat resistance, and weather resistance can be ensured with a simple structure.

[0016] The lid body may also be made of nickel, 42 alloy (registered trademark), or Kovar (registered trademark).

[0017] The base is generally made of ceramic. Nickel, 42 alloy, and Kovar have thermal expansion coefficients similar to those of ceramic, which helps prevent stress from occurring in the package when heated, making it easy to ensure airtightness between the lid body and the base. Furthermore, nickel, 42 alloy, and Kovar have excellent oxidation resistance, allowing the package to maintain its ability to protect the mounted electronic components for a long period of time.

[0018] The sealing material may be a metal or alloy containing at least one of tin, bismuth, and lead.

[0019] Tin, bismuth, and lead have relatively low melting points, which can lower the sealing temperature, while remaining solid at room temperature, making it easy to perform sealing and ensure airtightness.

[0020] The electronic component element may be a quartz crystal vibrating element.

[0021] With this configuration, it is possible to obtain a piezoelectric device that stably outputs a signal of a predetermined frequency.

[0022] The electronic device may further include a covering material that covers at least the sealing material exposed to the outside from the base and the lid body.

[0023] When the sealing material is reheated by reflow or the like after the device is manufactured, the sealing material melts, and the molten sealing material may enter the accommodating region due to the external air pressure, destroying the airtight seal.

[0024] According to the above configuration, even if the sealing material melts, the external air pressure is prevented from affecting the sealing material, and the airtight seal can be prevented from being destroyed.

[0025] As a result, the airtightness of the device can be ensured with a simple configuration.

[0026] The covering material may be formed so as to extend from a region where the sealing material is exposed to the outside from the base to at least a portion of the upper surface of the lid body.

[0027] According to the above configuration, the covering material is formed to cover at least a portion of the lid, thereby enhancing the mechanical strength of the lid made of metal foil. Furthermore, the top and side surfaces of the lid are also covered and protected, improving weather resistance. Furthermore, since printing can be performed on the covering material, printing can be easily performed on the device without processing the thin lid made of metal foil.

[0028] The coating material may be a thermosetting resin or a metal paste.

[0029] According to the above configuration, the covering material can be easily provided in the required area, and the device can be easily manufactured.

[0030] The device may further include a covering material made of adhesive that covers the sealing material exposed to the outside from the base and the lid body, and a reinforcing member that is joined via the covering material to the surface of the lid body opposite to the surface connected to the base.

[0031] Since a reinforcing member is provided in addition to the covering material, the mechanical strength of the lid body made of metal foil can be further increased.

[0032] The reinforcing member may also be made of metal, ceramic, or quartz.

[0033] With this configuration, the strength can be easily improved.

[0034] Furthermore, a method for manufacturing a device according to one embodiment of the present invention is a method for manufacturing a device in which an electronic component element mounted in a mounting area of ​​a base is sealed in a storage area surrounded by the base and a lid body, and includes the steps of mounting the electronic component element in the mounting area of ​​the base, placing the lid body on the base on which a sealing material has been formed, pressing the lid body in the thickness direction of the base and heating it to a temperature above the melting point of the sealing material to join the lid body to the base, and providing a coating material to cover at least the sealing material exposed to the outside from the base, wherein the lid body is metal foil and the sealing material contains a metal with a melting point of 265°C or less.

[0035] With this configuration, airtightness can be ensured with a simple configuration.

[0036] Furthermore, the covering material prevents the external air pressure from affecting the sealing material even if the sealing material melts, thereby preventing the airtight seal from being destroyed.

[0037] The method may further include a step of providing a reinforcing member on the back surface of the lid body opposite to the surface connected to the base, with the covering material made of adhesive interposed therebetween.

[0038] According to the above configuration, the mechanical strength of the lid body made of metal foil can be further increased, and the reinforcing member can be easily and efficiently bonded by using the covering material.

[0039] FIG. 1 is a cross-sectional view illustrating the configuration of a package for a piezoelectric device. FIG. 2 is a view illustrating the configuration of a lid and a base. FIG. 3 is a cross-sectional view illustrating the configuration of a package provided with a covering material. FIG. 4 is a cross-sectional view illustrating the configuration of a package provided with a reinforcing member and a covering material. FIG. 5 is a view illustrating a flow for manufacturing a piezoelectric device. FIG. 6 is a cross-sectional view illustrating an example of the configuration of a reinforcing member. FIG. 7 is a cross-sectional view illustrating an example of the configuration of a reinforcing member. FIG. 8 is a view illustrating the configuration of a sheet-like lid. FIG. 9 is a view illustrating the configuration of a sheet-like lid.

[0040] Devices incorporating electronic component elements may be sealed in a package. For example, in a piezoelectric device 1 incorporating a quartz crystal resonator element 2 as an electronic component element, the quartz crystal resonator element 2 may be vacuum-sealed to prevent changes in the characteristics of the quartz crystal resonator element 2 due to air resistance generated when the quartz crystal resonator element 2 vibrates.

[0041] The device and package will be described below using the piezoelectric device 1 as an example. In the following description, the direction of arrow U in Fig. 1 is defined as up, and the direction of arrow D in Fig. 1 is defined as down.

[0042] 1 to 5, a piezoelectric device 1 (quartz crystal resonator) in which a quartz crystal resonator element 2 is vacuum-sealed in a package will be described. Note that the quartz crystal resonator element 2 and other components are not shown in FIGS. 3 and 4.

[0043] As shown in FIGS. 1 and 2 , the package may have any shape as long as it can mount a quartz crystal resonator element 2 (electronic component element). For example, the package may be a substantially rectangular parallelepiped, including a base 5 that is substantially rectangular in plan view and a lid 7 that is also rectangular in plan view. The base 5 has a mounting area 4 for the quartz crystal resonator element 2. Mounting pads 5B are provided in the mounting area 4. The mounting pads 5B are provided corresponding to the terminals 2A of the quartz crystal resonator element 2, and the terminals 2A of the quartz crystal resonator element 2 are bonded to the mounting pads 5B via a conductive adhesive 5C, thereby mounting the quartz crystal resonator element 2 on the mounting area 4 of the base 5. The lid 7 is bonded (attached) to the base 5 to seal the mounting area 4 of the base 5. In other words, the piezoelectric device 1 on which the quartz crystal resonator element 2 is mounted is configured such that the lid 7 is bonded to the base 5 with the quartz crystal resonator element 2 mounted on the mounting area 4 of the base 5.

[0044] The lid 7 has a lid body 8 and a sealing material 9 provided on the entire back surface of the lid body 8, which is the surface that is bonded to the base 5. The lid body 8 is a metal foil, and the sealing material 9 is used to bond the base 5 and the lid body 8 together. When the lid body 8 is bonded to the base 5, a bonding portion 11 is formed between the lid body 8 and the base 5. In other words, the lid body 8 and the base 5 are bonded via the bonding portion 11 formed based on the sealing material 9, and the accommodation area 6 is hermetically sealed. The accommodation area 6 is surrounded by the base 5 and the lid 7, and is an area where the crystal vibrating element 2 mounted on the mounting area 4 of the base 5 is vacuum-sealed. The bonding portion 11 is formed when the sealing material 9 melts and then solidifies.

[0045] The base 5 is made of an insulating material such as ceramic. The base 5 has a recess (reference numeral omitted) that opens upward. The upper surface 5A of the frame surrounding this recess is flat, and a metal layer (described later) is formed in a rectangular frame shape. Note that the metal layer is not shown in FIG. 1 (the metal layer is also omitted in FIGS. 3, 4, 6, and 7). Mounting pads 5B that are conductively bonded to the crystal vibrating element 2 are formed on the inner bottom surface of the recess in the base 5. When the base 5 is made of ceramic, it is made of sintered ceramics, and therefore the base 5 has some warping. Therefore, if the lid body 8 is rigid, a gap may occur between the base 5 and the lid body 8. If a gap occurs between the base 5 and the lid body 8, the lid body 8 may not be properly bonded to the base 5, which may result in an inaccurate hermetic seal.

[0046] By making the lid body 8 out of metal foil, the lid body 8 becomes more easily deformed, and it is possible to deform and position the lid body 8 in accordance with the deformation (warping) of the base 5, and to tightly seal the lid body 8 against or close to the base 5 with the sealing material 9.

[0047] If the formation state of the sealing material 9 of the piezoelectric device 1 is destroyed, the airtightness is also destroyed, and the characteristics of the quartz vibrating element 2 are deteriorated. Even if the state of the sealing material 9 changes due to a change in the ambient environment of the piezoelectric device 1, such as an increase in ambient temperature, it is necessary to stabilize the formation state of the sealing material 9.

[0048] For example, there is a risk that at least a part of the bonded portion 11 will melt during heating by reflow or the like, and the airtight seal will be destroyed. This is because the accommodation area 6 is a vacuum, and the difference in air pressure with the outside air causes the melted bonded portion 11 to move toward the accommodation area 6.

[0049] In order to prevent the airtight seal from being destroyed, as shown in FIG. 3, the piezoelectric device 1 of this embodiment is provided with a covering material 15 that covers the sealing material 9 (joint portion 11) exposed to the outside from the base 5 and the lid main body 8.

[0050] By covering the exposed sealing material 9 (bonding portion 11) with the covering material 15, even if the bonding portion 11 melts, the bonding portion 11 is covered by the covering material 15 and does not come into contact with the outside air. Therefore, the covering material 15 suppresses the movement of the melted sealing material 9. As a result, the hermetic seal is prevented from being destroyed.

[0051] Furthermore, destruction of the lid body 8 may destroy the airtight seal. Therefore, the covering material 15 may be provided from a position covering the exposed sealing material 9 (bonding portion 11) to the entire upper surface of the lid body 8. The upper surface of the lid body 8 is the back surface opposite the bonding surface of the lid body 8 with the base 5. Note that the covering material 15 may be configured to be provided from a position covering the exposed sealing material 9 (bonding portion 11) to a position reaching a part of the upper surface of the lid body 8.

[0052] By providing the covering material 15 on the lid body 8, the mechanical strength of the lid body 8 (lid 7) made of metal foil can be supplemented, and the mechanical strength of the package can be ensured.

[0053] 4, a configuration may be adopted in which a reinforcing member 13 is provided to cover only the upper portion of the lid main body 8, and the exposed sealing material 9 (bonding portion 11) is covered with a covering material 15. The reinforcing member 13 may also be provided to cover at least a portion of the upper surface of the lid main body 8. In this case, the covering material 15 may be provided to reach the reinforcing member 13, and the reinforcing member 13 may be supported by the covering material 15, or the reinforcing member 13 may be supported on the upper portion of the lid main body 8 by an adhesive or the like.

[0054] Even with this configuration, the reinforcing member 13 maintains the mechanical strength of the piezoelectric device 1 (lid 7), while the coating material 15 covers the exposed sealing material 9 (joint 11), thereby preventing the airtight seal from being destroyed.

[0055] The outer dimensions of the base 5 in a plan view are, for example, a long side length of 2.0 mm and a short side length of 1.6 mm. As shown in Fig. 1, the lid 7 (lid main body 8) may be smaller than the planar dimensions of the base 5, but as shown in Fig. 3, the planar dimensions of the lid 7 may be the same as the planar dimensions of the base 5, or the planar dimensions of the lid 7 (lid main body 8) may be larger than the planar dimensions of the base 5.

[0056] [Method for Manufacturing Piezoelectric Device] A method for manufacturing the piezoelectric device 1 configured as above will be described with reference to FIGS. 2 and 4 and with reference to FIG.

[0057] First, the crystal vibrating element 2 is mounted on the mounting area 4 of the base 5 (step #1 in FIG. 5). At this time, the terminals 2A of the crystal vibrating element 2 are bonded to the mounting pads 5B provided on the base 5 with a conductive adhesive 5C or the like.

[0058] Next, a sealing material 9 is applied to the entire bonding surface of the lid body 8, which is made of metal foil, to form the lid 7 (step #2 in FIG. 5). The bonding surface of the lid body 8 is the surface where the lid body 8 is bonded to the base 5. The lid 7 may be formed before the crystal vibrating element 2 is mounted on the base 5.

[0059] Next, the lid 7 is placed on the base 5 (step #3 in FIG. 5 ). At this time, the lid 7 is placed on the base 5 so that at least a portion of the sealing material 9 is in contact with the upper surface 5A of the frame, which is the surface to which the lid 7 is bonded.

[0060] Next, the lid body 8 is pressed from above toward the base 5 (in the thickness direction of the base 5) and heated to a temperature equal to or higher than the melting point of the sealing material 9, thereby bonding the lid body 8 to the base 5 (step #4 in FIG. 5). With the lid body 8 bonded to the base 5, the melted sealing material 9 solidifies to form a bonded portion 11. The pressure at this time can be applied by any method.

[0061] Next, the reinforcing member 13 is installed on the top (on the front surface) of the lid body 8 (step #5 in FIG. 5). By providing the reinforcing member 13, the mechanical strength of the piezoelectric device 1 (package) can be ensured as described above. Note that if the mechanical strength of the piezoelectric device 1 (package) can be sufficiently ensured, the reinforcing member 13 does not need to be provided.

[0062] The reinforcing member 13 may be bonded to the lid body 8 with an adhesive or the like, or may be held to the lid 7 with a covering material 15 made of an adhesive, as will be described later (the configuration of FIG. 4).

[0063] Finally, a covering material 15 is provided (formed) in a position that covers the sealing material 9 (joint portion 11) exposed to the outside from the base 5 and the lid body 8, thereby completing the manufacture of the piezoelectric device 1 (step #6 in Figure 5).

[0064] In this way, by covering the exposed sealing material 9 (bonding portion 11) with the covering material 15, even if the bonding portion 11 melts, the bonding portion 11 is covered by the covering material 15 and does not come into contact with the outside air. Therefore, the covering material 15 suppresses the movement of the melted bonding portion 11 (sealing material 9). As a result, the airtight seal is prevented from being destroyed. Note that if there is no need to consider the risk of the airtightness of the bonding portion 11 being destroyed, the covering material 15 does not need to be provided.

[0065] 3, the piezoelectric device 1 (package) may be configured such that the exposed sealing material 9 (bonding portion 11) is covered with a coating material 15, or as shown in FIG. 7 described below, the exposed sealing material 9 (bonding portion 11) is covered with a reinforcing member 13. When the exposed sealing material 9 (bonding portion 11) is covered with the reinforcing member 13, the coating material 15 does not need to be provided, or the reinforcing member 13 may be held by the coating material 15. Regardless of whether the coating material 15 is provided or not, the reinforcing member 13 may be bonded to the lid body 8 with an adhesive or the like as described above.

[0066] [Lid and Base] The lid body 8 of the lid 7 is a kovar metal foil, and is a metal foil that contains kovar at least in part. The thickness d (see FIG. 2) of the lid body 8 is 0.003 mm or more and 0.03 mm or less. If the thickness d of the lid body 8 is 0.003 mm or more, damage to the lid 7 is suppressed, and handling of the piezoelectric device 1 is also facilitated. Furthermore, if the thickness d of the lid body 8 is 0.03 mm or less, elastic return of the lid 7 after pressure is applied can be suppressed.

[0067] Kovar has a thermal expansion coefficient close to that of the ceramic that constitutes the base 5, and therefore is less likely to generate stress in the package (base 5 and lid 7) even when heated during reflow or the like after sealing, thereby preventing deterioration of the airtightness of the piezoelectric device 1 (package). Furthermore, Kovar has excellent oxidation resistance, so it can maintain airtightness over a long period of time, maintaining the sealing of the housing area 6 and protecting the mounted quartz crystal vibrating element 2.

[0068] Furthermore, because the lid body 8 is made of metal foil and has a thickness d of 0.003 mm or more and 0.03 mm or less, even if the base 5 warps due to heating or the like, the lid body 8, which is sufficiently thin relative to the amount of deformation, is pressurized and can easily deform to conform to the warpage of the base 5. As a result, the base 5 and the lid body 8 are joined in a state in which the lid body 8 is plastically deformed so as to close the gap between them, and therefore the airtightness reliability of the piezoelectric device 1 (package) can be easily ensured.

[0069] The lid body 8 may be a very thin and extremely flexible nickel film having a thickness d of 0.005 mm.

[0070] The lid body 8 may also be plated as shown in FIG. 2 . For example, the lid body 8 may be made of Kovar metal foil and have at least one of a nickel thin film 17 and a gold thin film 18 formed by plating or sputtering. The provision of the nickel thin film 17 allows the lid 7 and the base 5 to be bonded with a small amount of sealing material 9. Furthermore, the provision of the gold thin film 18 at the interface between the lid body 8 and the sealing material 9 or on at least a portion of the surface of the lid body 8 can improve adhesion between the lid body 8 and the sealing material 9 (bonding portion 11) and prevent the surface of the lid body 8 from oxidizing. Note that at least one of the nickel thin film 17 and the gold thin film 18 may be omitted as long as the lid 7 and the base 5 are sufficiently bonded.

[0071] Furthermore, the thickness d of the lid body 8 is not limited to 0.003 mm or more and 0.03 mm or less, but is preferably at least 0.03 mm or less, and more preferably 0.01 mm or less. When the thickness d of the lid body 8 is 0.03 mm or less, the lid 7 (lid body 8) hardly returns to its original shape after pressure is applied, making it easier to achieve heat-resistant airtightness.

[0072] 2, plating (metal layer) is applied to the upper surface 5A of the frame, which is the bonding area between the base 5 and the lid 7. The plating may extend to the side portions of the frame of the base 5. The bonding area is the area of ​​the base 5 that is bonded to the lid 7. Any plating may be applied as needed to ensure bonding (airtightness) and strength between the base 5, such as ceramic, and the lid 7 (bonding portion 11).

[0073] For example, the base 5 is formed by laminating a tungsten metallization 21, a nickel plating 22, and a gold plating 23 in this order on a ceramic. The gold plating 23 is formed at the same time as the mounting pads 5B of the base 5.

[0074] 2, the sealing material 9 is provided on the entire lower surface (rear surface) of the lid main body 8. Here, the lower surface (rear surface) of the lid main body 8 is the surface of the lid 7 that is joined to the base 5.

[0075] The sealing material 9 is a metal that can bond the base 5 and the lid 7 together by melting, and has a melting point lower than the peak reflow temperature of the equipment in which the piezoelectric device 1 is mounted. For example, when the peak reflow temperature is 260°C ± 5°C, the sealing material 9 is a metal that has a melting point of 265°C or lower, such as tin.

[0076] In this way, by using a sealing material 9 containing a metal having a melting point below the reflow peak temperature, airtight sealing can be achieved at low temperatures when joining the lid 7 to the base 5, and gas generation from the conductive adhesive 5C that fixes the quartz oscillator element 2 to the mounting area 4 of the base 5 can be suppressed.

[0077] In particular, because the lid body 8 is made of metal foil, even if the base 5 is warped (deformed or distorted), the lid body 8 deforms along the base 5, preventing the gap between the base 5 and the lid body 8 from becoming larger. As a result, the sealing material 9 spreads sufficiently between the lid body 8 and the base 5, and the lid body 8 and the base 5 can be joined together in a highly airtight state.

[0078] The thickness of the sealing material 9 is optional, but is preferably 0.005 mm or less. This allows the lid 7 and base 5 to be bonded together with the minimum amount of sealing material 9 required. If the sealing material 9 is very thin, there is little chance of the sealing material 9 splashing during bonding, and therefore the sealing material 9 can be disposed over the entire underside of the lid body 8.

[0079] The sealing material 9 is not limited to being provided on the entire lower surface (rear surface) of the lid main body 8, but may be provided in a shape (rectangular frame shape or ring shape) corresponding to the upper surface 5A of the frame of the base 5, or may be provided on at least a part of the region of the lid main body 8 to be joined to the base 5. This makes it possible to join the lid 7 and the base 5 using the minimum amount of sealing material 9 required.

[0080] The sealing material 9 is not limited to tin, but may include a metal or an alloy thereof having a melting point equal to or lower than the peak reflow temperature (e.g., 265°C). This allows airtight sealing at a low temperature when bonding the lid 7 to the base 5, and suppresses gas generation from the conductive adhesive 5C that bonds the quartz crystal vibrating element 2 to the mounting area 4 of the base 5.

[0081] Furthermore, since the piezoelectric device 1 requires strength, heat resistance, airtightness, and weather resistance, the sealing material 9 preferably contains a metal that has strength, heat resistance, airtightness, and weather resistance. Here, having heat resistance means that the characteristics can be maintained without destroying the internal vacuum (airtightness of the housing region 6) through at least two reflow processes.

[0082] [Reinforcing Member] The reinforcing member 13 is made of metal. By providing the reinforcing member 13 on the lid body 8 (the configuration in FIG. 4 ), the mechanical strength of the lid 7 (package) can be improved, and the airtightness can be improved. Additionally or separately, the reinforcing member 13 may be provided from the top to the side of the lid body 8 to a position that covers the sealing material 9 (joint portion 11) exposed from the base 5 and the lid body 8 to the outside (the side opposite the storage area 6). This prevents the sealing material 9 (joint portion 11) from melting and breaking down the sealing material 9 (joint portion 11), thereby destroying the airtightness. The reinforcing member 13 may be supported on at least one of the lid body 8 and the base 5 by an adhesive or the like, but may also be supported by a covering material 15.

[0083] [Covering Material] As described above, the covering material 15 is provided so as to cover at least the sealing material 9 (bonding portion 11) exposed to the outside (opposite side to the storage area 6) from the base 5 and the lid main body 8.

[0084] Specifically, if the bonding portion 11 (sealing material 9) is exposed during reflow, the sealing material 9 (bonding portion 11) may melt at the peak temperature, contaminating the inside of the accommodation area 6 with the sealing material 9 and causing a hole in the bonding portion 11. In other words, after the sealing material 9 melts, a driving force that pushes the sealing material 9 inward is generated by the external air pressure, causing the sealing material 9 to flow into the accommodation area 6 of the package. For this reason, a covering material 15 is provided to cover the exposed bonding portion 11 so that even if the bonding portion 11 melts, a pressure difference between atmospheric pressure and vacuum does not occur (so that a driving force that pushes the sealing material 9 inward does not occur).

[0085] The covering material 15 is preferably a material that is at least one of flexible, thermosetting, and weakly airtight, such as a resin (epoxy adhesive) that has a curing temperature of 260° C. or less.

[0086] In other words, the covering material 15, which has a certain degree of airtightness, covers and protects the exposed portion of the sealing material 9 (joint 11), so even if the temperature reaches the melting point of the sealing material 9 during reflow, the sealing material 9 is prevented from being immediately pushed into the interior of the piezoelectric device 1 (accommodation area 6) due to the difference in air pressure between the inside and outside of the piezoelectric device 1. Therefore, by providing the covering material 15, the piezoelectric device 1 can withstand short-term high-temperature heating. Furthermore, because the covering material 15 can protect the surfaces of the lid 7 and the sealing material 9, improved weather resistance of the piezoelectric device 1 can be expected.

[0087] The flexibility of the coating material 15 makes it easy to provide the coating material 15 in the required area. Furthermore, the thermosetting property of the coating material 15 makes it easy to form the coating material 15 that is airtight with respect to the sealing material 9 (bonding portion 11) by heating the coating material 15 in the required area.

[0088] The joint 11 requires strong (long-term) airtightness in order to maintain the airtightness of the housing region 6 for a long period of time and maintain the characteristics of the quartz crystal resonator element 2. The covering material 15 only needs to prevent an air pressure difference from occurring at the joint 11 while the joint 11 is melted by reflow or the like, so weak airtightness (short-term airtightness) of the covering material 15 is sufficient.

[0089] In other words, although materials such as epoxy resin cannot completely block moisture and some gas molecules (they pass through slowly), even if there is a peak reflow temperature and a substrate heat capacity, the heating time is at most about 1 to 2 minutes (the peak reflow temperature is usually about 1 minute at 260°C), so the number of gas molecules that pass through during this time is not large. Therefore, the covering material 15 may have greater breathability (short-term breathability) than the sealing material 9.

[0090] As such, there is a risk that a small amount of sealing material 9 will melt and destroy the airtightness, and the coating material 15 made of epoxy or the like does not provide long-term airtightness. However, while the sealing material 9 maintains airtightness over the long term, even if the sealing material 9 (joint 11) melts in the short term, the coating material 15 can maintain airtightness during that time. In other words, by combining the sealing material 9 and the coating material 15, a flexible, high-strength, and highly heat-resistant airtight seal can be achieved.

[0091] Other Embodiments (1) In the above embodiment, the reinforcing member 13 may be sized to cover a portion of the upper surface 5A of the base 5 as shown in Fig. 4, or may be sized to cover the entire upper surface 5A of the base 5 as shown in Fig. 6 and Fig. 7. Note that the quartz crystal vibrating element 2 and the like are not shown in Fig. 6 and Fig. 7.

[0092] The reinforcing member 13 may be supported on the lid 7 by any method such as an adhesive, or may be supported by using a covering material 15 as shown in Figures 4 and 6. This allows the reinforcing member 13 to be supported efficiently while maintaining the airtightness of the sealing material 9 (bonding portion 11).

[0093] 7, the reinforcing member 13 may have a flange 13A, and the reinforcing member 13 may be disposed so that the flange 13A covers the sealing material 9 (joint 11) exposed to the outside (the side opposite to the storage area 6) from the base 5 and the lid main body 8. This allows the airtightness of the joint 11 to be maintained even if the sealing material 9 (joint 11) melts.

[0094] Furthermore, when supporting the reinforcing member 13 with the covering material 15, by providing the covering material 15 between the flange portion 13A and the base 5, the reinforcing member 13 can be supported on the lid 7 (package) while maintaining airtightness using a minimum amount of covering material 15.

[0095] (2) In each of the above embodiments, the lid main body 8 may be a sheet-like sheet lid 26. That is, as shown in Figures 8 and 9, the sheet lid 26, which is the lid main body 8, is large enough to seal a plurality of bases 5, and the sealing material 9 is provided at least in the region of the lid main body 8 to be joined to each of the bases 5.

[0096] For example, the sheet lid 26 is used by being attached to a base assembly in which a plurality of bases 5 are joined (integrally formed) or a base assembly in which a plurality of bases 5 are arranged on a single tray. By using the sheet-like lid main body 8 (sheet lid 26) in combination with a base assembly made up of a large number of bases 5, the piezoelectric device 1 can be manufactured efficiently.

[0097] The sealing material 9 is provided only in the area of ​​the sheet lid 26 that overlaps with the base 5 in a plan view (the area to be bonded to the base 5), i.e., in a shape (rectangular frame or ring shape) corresponding to the upper surface 5A of the frame of the base 5 ( FIG. 8 ). By providing the sealing material 9 only in the area to be bonded to the base 5, the sheet lid 26 and the base 5 can be easily and firmly bonded to produce the piezoelectric device 1. While the sealing material 9 may be provided only in the area to be bonded ( FIG. 8 ), it is preferable that the sealing material 9 be provided on the entire surface of the sheet lid 26 that is to be bonded to the base 5 ( FIG. 9 ). By providing the sealing material 9 on the entire surface of the sheet lid 26 that is to be bonded to the base 5, the sheet lid 26 can be easily placed over the base assembly without having to align the sheet lid 26 with the base assembly. Furthermore, in the configuration in which the sealing material 9 is provided only in the area to be bonded ( FIG. 8 ), the sealing material 9 may be provided on at least a portion of the area to be bonded, rather than the entire area to be bonded. To summarize the above, it is preferable that the sealing material 9 be provided on the entire surface of the seat lid 26 that is to be joined to the base 5, but it may also be provided on the entire or part of the joined area of ​​the seat lid 26, or on at least a part of the surface of the seat lid 26 that is to be joined to the base 5, including the joined area.

[0098] Then, a sheet lid 26 is placed over the lined-up bases 5, and the sheet lid 26 is heated while being pressed vertically (from top to bottom) against the bases 5 with a roller or the like to melt the sealing material 9 and bond the sheet lid 26 to the bases 5. Thereafter, the sheet lid 26 is cut into individual bases 5, thereby obtaining a plurality of piezoelectric devices 1.

[0099] When the seat lid 26 is cut along the base 5 , the planar dimensions of the lid 7 (lid body 8 ) become the same as the planar dimensions of the base 5 .

[0100] (3) In each of the above embodiments, the lid body 8 is not limited to Kovar, but may be a metal foil of nickel or 42 alloy. These metals have a thermal expansion coefficient of 4.0×10 －６ / ℃~12.8×10 －６ / °C, and the thermal expansion coefficient is close to that of ceramic. Therefore, even if the package (base 5 and lid 7) is heated during reflow or the like after sealing, stress is unlikely to be generated, and deterioration of the airtightness of the piezoelectric device 1 (package) can be suppressed. In particular, when the lid body 8 is made of a metal foil such as Kovar or 42 alloy, the thermal expansion coefficient of these metals is 4.0 × 10 －６ / ℃~6.0×10 －６ / °C range, which is closer to the thermal expansion coefficient of ceramics and is therefore preferred.

[0101] In the case of the lid body 8 made of 42 alloy or the like, a large pressure (pressing force) is required to conform to the warpage of the base 5, and it is not easy to attach the lid 7 to the base 5. Therefore, the lid body 8 may be made of simple copper (Cu).

[0102] Furthermore, it is preferable that the metal foil constituting the lid body 8 is a metal that has the deformability to conform to the base 5, the airtightness to seal the storage area 6, and the heat resistance to not be destroyed by heat treatment such as reflow, but conversely, any metal may be used as long as it has the deformability, airtightness, and heat resistance.

[0103] (4) In each of the above embodiments, the sealing material 9 is not limited to tin alone, but may be a metal or alloy containing at least one of tin, bismuth, and lead. Among these metals and alloys, those that melt at relatively low temperatures and remain solid at room temperature can be easily melted and then solidified. Therefore, by simply performing low-temperature heat treatment, it is possible to easily obtain an airtight seal while maintaining the characteristics of the quartz crystal resonator element 2.

[0104] (5) In each of the above embodiments, the covering material 15 may be a thermosetting resin or a metal paste. For example, the metal paste may be an Ag paste. The covering material 15 may have at least weak airtightness. This increases the number of material options, allowing for efficient provision of an appropriate covering material 15.

[0105] The covering material 15 may be provided so as to cover at least a portion of the upper surface of the lid main body 8. In this case, the reinforcing member 13 may not be provided, or the reinforcing member 13 may be provided via the covering material 15. When the reinforcing member 13 is provided via the covering material 15, the covering material 15 may hold the reinforcing member 13. Conversely, if the reinforcing member 13 or the like sufficiently prevents the exposed sealing material 9 from being destroyed, the covering material 15 may not be provided.

[0106] The covering material 15 is formed to cover the lid body 8, thereby supplementing the mechanical strength of the lid body 8 made of metal foil. Also, the covering material 15 covers the top and side surfaces of the lid body 8, thereby protecting the piezoelectric device 1 (package) and improving the weather resistance of the piezoelectric device 1 (package). Furthermore, since printing can be performed on the covering material 15, there is no need to process the thin lid body 8 made of metal foil for printing.

[0107] (6) In each of the above embodiments, the reinforcing member 13 is not limited to metal, but may be made of any of ceramic, quartz, and glass. When the reinforcing member 13 is made of a metal material, high mechanical strength can be obtained. Furthermore, when the reinforcing member 13 is made of ceramic or quartz, the hardness of the surface can be particularly increased.

[0108] The reinforcing member 13 may be made of, for example, the same ceramic plate material as the base 5, and may be bonded to the lid body 8 with a resin adhesive. In order to improve weather resistance, the reinforcing member 13 may have a thick nickel sputtering on the outermost layer.

[0109] (7) In each of the above embodiments, after the lid main body 8 or the seat lid 26 is joined to the base 5, the periphery of the lid main body 8 and the periphery of the seat lid 26 may be cut.

[0110] Specifically, the lid body 8 is cut so that the outer peripheral edge of the lid body 8 is located inside the outer peripheral edge of the base 5 in a plan view. In other words, by cutting the outer peripheral edge of the lid body 8, the outer peripheral edge of the cut lid body 8 does not protrude from the side surface of the base 5. Note that if the lid body 8 before cutting does not protrude from the outer edge of the base 5 in a plan view, there is no need to cut the lid body 8.

[0111] In addition, in the case of the seat lid 26, when or after cutting the seat lid 26 into individual pieces, the seat lid 26 is cut so that the outer peripheral edge of the lid body 8 is inside the outer peripheral edge of the base 5 when viewed in a plane.

[0112] Because the lid body 8 is thin, if the lid body 8 protrudes from the outer edge of the base 5, external forces are likely to be applied to the lateral sides of the lid body 8, making it easier for the lid body 8 to peel off from the base 5. By positioning the lid body 8 inside the outer edge of the base 5, external forces are prevented from being applied to the lateral sides of the lid body 8, making it more likely for the lid body 8 to peel off from the base 5. The cutting can be performed by any method, for example, laser cutting.

[0113] (8) In each of the above embodiments, the electronic component element may be the crystal resonator element 2, or may be an IC and the crystal resonator element 2 that together with the crystal resonator element 2 form an oscillator circuit. The device may be any piezoelectric device 1 such as a crystal resonator. Furthermore, the device is not limited to the piezoelectric device 1, but may be any electronic device. In this case, the electronic component element mounted on the device is not limited to the crystal resonator element 2, but may be any electronic component element such as an IC chip.

[0114] The present invention is applicable to devices including electronic component elements and lids used in device packages.

[0115] REFERENCE SIGNS LIST 1 Piezoelectric device 2 Crystal vibration element (electronic component element) 4 Mounting area 5 Base 6 Housing area 7 Lid 8 Lid body 9 Sealing material 11 Bonding portion 13 Reinforcing member

Claims

1. A lid to be attached to a base on which an electronic component element is mounted in a mounting area, comprising: a lid body made of metal foil; and a sealing material containing a metal with a melting point of 265°C or less, which is provided in at least a portion of the bonding area of ​​the lid body to the base.

2. A lid that is attached to a base on which an electronic component element is mounted in a mounting area, comprising: a lid body made of metal foil; and a sealing material containing a metal with a melting point of 265°C or less that is provided in at least a portion of the bonding area of ​​the lid body with the base, wherein the lid body is in the form of a sheet large enough to seal a plurality of the bases, and the sealing material is provided in at least the bonding area of ​​the lid body with each of the bases.

3. A lid according to claim 1 or 2, wherein the lid body has a thickness of 0.003 mm or more and 0.03 mm or less.

4. A lid according to any one of claims 1 to 3, wherein the lid body is made of nickel, 42 Alloy (registered trademark) or Kovar (registered trademark).

5. A lid according to any one of claims 1 to 4, wherein the sealing material is a metal or alloy containing at least one of tin, bismuth, and lead.

6. A lid according to any one of claims 1 to 5, wherein the electronic component element is a quartz crystal oscillator element.

7. A device comprising: a base having a mounting area; an electronic component element to be mounted in the mounting area of ​​the base; a lid body joined to the base so as to cover the mounting area; and a sealing material joining the base and the lid body, wherein the electronic component element is sealed within the accommodating area by the base and the lid body; the lid body is a metal foil; and at least a portion of the sealing material contains a metal having a melting point of 265°C or less.

8. The device according to claim 7, wherein the lid body has a thickness of 0.003 mm or more and 0.03 mm or less.

9. The device according to claim 7 or 8, further comprising a covering material that covers at least the sealing material exposed to the outside from the base and the lid body.

10. The device according to claim 9, wherein the covering material is formed from the area where the sealing material is exposed to the outside from the base to at least a part of the area of ​​the upper surface of the lid body.

11. The device of claim 9, wherein the coating material is a thermosetting resin or a metal paste.

12. The device according to claim 7 or 8, further comprising a covering material made of adhesive that covers the sealing material exposed to the outside from the base and the lid body, and a reinforcing member that is bonded via the covering material to the surface of the lid body opposite to the surface connected to the base.

13. The device of claim 12, wherein the reinforcing member is made of metal, ceramic, or quartz.

14. A method for manufacturing a device in which an electronic component element mounted in a mounting area of ​​a base is sealed in a storage area surrounded by the base and a lid body, comprising the steps of: mounting the electronic component element in the mounting area of ​​the base; placing the lid body, on which a sealing material has been formed, on the base; pressing the lid body in the thickness direction of the base and heating it to a temperature above the melting point of the sealing material to bond the lid body to the base; and providing a covering material so as to cover at least the sealing material exposed to the outside from the base, wherein the lid body is metal foil and the sealing material contains a metal with a melting point of 265°C or less.

15. The method for manufacturing a device according to claim 14, wherein the lid body has a thickness of 0.003 mm or more and 0.03 mm or less.

16. The method for manufacturing a device according to claim 14, further comprising the step of providing a reinforcing member via the covering material made of adhesive on the back surface of the lid body opposite the surface connected to the base.

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