JP2006156513A - Lid for package and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the height of a package by thinly and highly accurately forming a brazing material on a lid. <P>SOLUTION: In manufacturing the lid 5 which airtightly seals the opening 4 of a case 3 in a package 1 housing an electronic component 2, a metallic sheet having such a size that many lids 5 can be taken from the sheet is used as a starting material. A masking layer is provided on the surface of the metallic sheet and many annular openings are formed in the masking layer. At the portions corresponding to the openings, a brazing material 9 is precipitated on the surface of the metallic sheet by plating an Au-Sn alloy. After the masking layer is peeled from the metallic sheet, many lids 5 are manufactured from the metallic sheet by removing the unnecessary portions of the metallic sheet by cutting or etching. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a package lid for hermetically sealing an opening of a case in a package for storing electronic components, and a method for manufacturing the lid.

  Conventionally, a technique is known in which a package is formed by bonding a lid of this type to a case with a brazing material provided on the lid. For example, as shown in FIG. 6 (a), a low melting point metal night is punched out with a press to form an annular brazing material foil 51, and the brazing material foil 51 is reflowed as shown in FIG. 6 (b). A technique is known in which a lid 52 is bonded to a case 53 with a brazing filler metal foil 51 as shown in FIG. However, this conventional technique has the following problems.

(1) In order to punch the brazing filler metal foil 51, it is necessary to use a relatively thick metal stay, and the reduction of the package height is limited.
(2) The brazing material foil 51 is difficult to handle, the positioning accuracy with respect to the lid 52 is poor, and the manufacturing efficiency of the lid 52 is also reduced.
(3) The shape of the brazing material foil 51 is disturbed by reflow, and a part of the brazing material may adhere to the inner surface of the case 53.

  Conventionally, as shown in FIG. 7, a technique is also known in which a conductive paste 55 is filled in an opening 57 of a mask 56 by screen printing and a brazing material layer 59 is applied to the surface of the lid 58. However, this conventional technique has the following problems.

(4) Thinning of the brazing material layer 59 is restricted, and it is difficult to adjust the thickness.
(5) The conductive paste 55 tends to exude from the opening 57, and the shape accuracy of the brazing material layer 59 is deteriorated.
(6) When the lid 58 is heat-sealed, the organic components in the conductive paste 55 are gasified, and the outgas has an adverse effect on the electronic components in the package.

Furthermore, conventionally, a lid in which a brazing material is applied to a metal lid by rolling has been proposed. For example, Patent Document 1 describes a technique in which a brazing material foil is joined to a lid formed by laminating a plurality of Ni-based metals by rolling to increase the adhesion of the brazing material to the case. Patent Document 2 describes a technique for preventing generation of outgas by clad a copper layer and a brazing filler metal layer on a cover made of Kovar by rolling.
JP 2000-164746 A JP 2003-158111 A

However, the lid in which the brazing material is applied by rolling has the following problems.
(7) When a material having poor cold pressure weldability is used as the brazing material, the joining force of the brazing material to the lid becomes insufficient.
(8) Since a brazing material is applied to the entire surface of the lid, it is necessary to increase the bonding temperature in anticipation of thermal diffusion in addition to high material costs when using a noble metal material such as Au or Ag for the brazing material. There is a risk of heat damage to the case and electronic components.
(9) Large-scale equipment is required for rolling, and the manufacturing cost of the lid is high.

  In view of the above problems, an object of the present invention is to provide a lid for a package capable of forming a brazing material thinly and with high accuracy, and a method for efficiently and inexpensively manufacturing this lid.

  In order to solve the above problems, a lid for a package according to the present invention is a lid that hermetically seals an opening of a case in a package that houses an electronic component, and includes a metal lid and a lid. And a brazing material that is bonded to the case, and the brazing material is formed in an annular shape around the periphery of the lid by plating.

  Here, the package is a container that constitutes various electronic devices together with the electronic components housed therein, and includes a case and a lid. Examples of the electronic component include a crystal oscillator, a piezoelectric component such as a piezoelectric vibrator and a SAW filter, a surface acoustic wave element, an optical element, an IC chip, a transistor, a resistor, a capacitor, and a diode. One type of electronic component may be stored in the package, or a plurality of types of electronic components may be stored.

  The shape of the case is not particularly limited, and examples thereof include a cavity shape, a flat shape, and an H shape. As a molding material for the case, for example, various insulating materials such as high temperature fired ceramic (HTCC), low temperature fired ceramic (LTCC), liquid crystal polymer (LCP), Teflon (registered trademark), fluororesin, and glass epoxy can be used. Moreover, it is also possible to use a container having a multilayer structure including an inner layer circuit as a case.

  The lid is a member that hermetically seals the opening of the case, and includes a lid and a brazing material. For the lid, a metal material having high smoothness of the brazing material joint surface and high heat dissipation effect is used. For example, a metal plate such as Fe—Ni alloy (42 alloy) or Fe—Ni—Co alloy (Kovar) can be preferably used. The shape of the lid is preferably a flat shape that is advantageous for reducing the height of the package. However, when the case has a flat shape, a cap-shaped lid having a flange portion around it can also be used.

  The brazing material is a sealing material that hermetically bonds the lid to the end face on the opening side of the case, and is formed in an annular shape on the peripheral edge of the lid by electrolytic plating or electroless plating. The shape of the brazing material is not particularly limited as long as it is an annular shape that matches or resembles the end face of the case, but is generally a quadrangular annular shape. The brazing material may be formed directly on the surface of the lid, or may be formed via a base plating layer made of Ni, Au, or the like. Further, in order to prevent oxidation of the brazing material, an antioxidant film such as Ni or Au may be plated on the surface (surface facing the case).

  As the brazing material plating material, for example, a low melting point metal material such as Au, Au—Sn alloy, Ag—Sn alloy, Sn—Zn alloy or solder can be used. In particular, the Au—Sn alloy has a higher melting point than solder, and is not likely to be melted by heat at the time of device mounting, which is advantageous for high airtightness of the package. In addition, Au—Sn alloy is less expensive than Au, does not contain harmful lead, unlike solder, and generates less outgas when adhering to the case. Specifically, a gold-tin alloy or a tin-gold alloy having a melting point of 217 to 320 ° C. and a Sn content of 10 to 90% by weight can be preferably used.

  A manufacturing method of a lid for a package according to the present invention uses a metal plate having a size capable of removing a plurality of lids in manufacturing a lid that hermetically seals an opening of a case in a package that houses electronic components. A masking layer having a plurality of annular openings is provided on the surface of the plate, a brazing material is formed on the surface of the metal plate by plating at a portion corresponding to the annular opening, and the masking layer is peeled off from the metal plate. The unnecessary portion is removed, and a plurality of lids are manufactured from a single metal plate.

  Here, as the metal plate, a hoop material or a sheet material having a size capable of acquiring a large number of lids from one sheet can be used. In order to improve the wettability of the brazing material to the metal plate, a base plating layer such as Ni or Au may be provided on the surface of the metal plate. It is preferable to use an Au-Sn alloy for the brazing material for the reason described above. In addition, it is preferable to provide a step of heating the metal plate and gasifying and removing organic components contained in the metal plate and the brazing material before removing unnecessary portions of the metal plate. By so doing, the organic component can be purged during the manufacturing process of the lid, and the amount of outgas generated when the lid is sealed can be more effectively suppressed.

  In the step of removing the unnecessary portion (joint portion) of the metal plate, for example, a method of removing the unnecessary portion of the metal plate by cutting can be employed. According to this method, it is possible to manufacture a lid with high outer shape accuracy at a lower cost by sharply cutting the periphery of the lid using a press machine or a laser processing machine. Moreover, you may employ | adopt the method of removing the unnecessary part of a metal plate by an etching. In this case, foreign matter adhering to the lid can be cleaned at the same time as etching, and the lid can be manufactured with a relatively small-scale facility.

  According to the lid of the present invention, the brazing material can be formed thinly and with high precision by plating, and there is an effect that the miniaturization and precision of the package can be easily achieved. Moreover, according to the manufacturing method of this invention, there exists an effect which can manufacture many lids efficiently and cheaply from one metal plate.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the package 1 according to this embodiment includes a case 3 that houses an electronic component 2 and a lid 5 that hermetically seals an opening 4 of the case 3. The case 3 is formed into a flat quadrangular shape using a low-temperature fired ceramic material or the like, and a cavity 6 in which the electronic component 2 is installed is provided on the inside thereof. A metallization layer 7 is applied.

  The lid 5 includes a lid body 8 having an area slightly smaller than that of the case 3 and a brazing material 9 for bonding the lid body 8 to the case 3. The lid 8 is formed, for example, by cutting a sheet material (discontinuous material) made of Kovar 30 to 200 μm into a size of 2 mm in length and 2.5 mm in width, and a surface Ni plating layer on the front and back surfaces thereof. 10 is provided. An Au plating layer 11 is deposited on the peripheral surface of the lid 8 via a Ni plating layer 10, and a brazing material 9 is formed in a square ring shape by electrolytic plating via the Au plating layer 11. The lid 5 is sealed to the case 3 by welding the brazing material 9 to the metallized layer 7.

  In this embodiment, an Au—Sn alloy having a melting point of 217 to 320 ° C. and a Sn content of 10 to 90% by weight is used for the brazing material 9. The thickness of the brazing material 9 is 1 to 50 μm, the thickness of the Au plating layer 11 is 0.01 μm, the thickness of the base Ni plating layer 10 is 0.1 to 5 μm, and the thickness of the metallized layer 7 Is 0.3 to 3.0 μm. For sealing the lid 5 to the case 3, means such as thermocompression bonding, electron beam welding, seam welding, etc. are used.

Next, in the package 1 configured as described above, a method for manufacturing the lid 5 will be described in the order of steps shown in FIGS.
(A) Using a metal plate 13 (sheet material made of Kovar) having a size capable of obtaining a large number of lids 5 as a starting material, a base Ni plating layer 10 is formed on the front and back surfaces thereof.
(B) A masking layer 14 made of an exposure film is applied to the front and back surfaces of the metal plate 13, and the masking layer 14 on the front surface side (the brazing material bonding surface side) is exposed to form a large number of rectangular annular openings 15. To do. A liquid resist may be used for the masking layer 14.
(C) The metal plate 13 is carried into the plating tank, and the Au plating layer 11 is formed on the surface of the metal plate 13 by Au flash plating at a portion corresponding to the annular opening 15.

(D) Next, a brazing material 9 is formed on the surface of the metal plate 13 by electrolytic plating using an Au—Sn alloy as a plating material.
(E) Subsequently, after peeling the masking layer 14 from the metal plate 13, the metal plate 13 is heated to gasify and remove the organic components contained in the metal plate 13 and the brazing material 9. As a result, as shown in FIG. 4, the square annular brazing material 9 is formed in a large number of regions (the same number of regions as the annular openings 15) of the metal plate 13. In FIG. 4, reference numeral 16 denotes a plating electrode for the Au plating layer 11 and the brazing material 9.
(F) Thereafter, the metal plate 13 is punched out along the outline of the lid body 8 by a press machine, and unnecessary portions (joint portions shown in FIG. 4) of the metal plate 13 are removed by cutting. A large number of lids 5 are manufactured.

  Note that, after the steps (a) to (e) described above, unnecessary portions of the metal plate 13 can be removed by etching as shown in FIG. In this case, a resist is deposited on the surface of the metal plate 13, unnecessary portions of the metal plate 13 are removed by liquid phase or vapor phase etching, a large number of lids 5 are formed, and grooves 18 are formed between the adjacent lids 5. And the connecting portion 19 are formed. Then, in a state where the lids 5 are bundled together by the connecting portions 19, the metal plate 13 is carried into the next sealing step, the connecting portions 19 are cut off, the lid 5 is cut off from the metal plate 13, and the lid 5 is a case. Seal to 3.

According to the lid 5 having the above configuration and the manufacturing method thereof, the following effects can be obtained.
(A) Since the brazing material 9 is formed by plating, the adhesive layer between the case 3 and the lid 5 can be thinned to achieve a low profile of the package 1.
(B) The thickness of the adhesive layer can be easily adjusted according to the installation conditions of the package 1 and the thickness or area of the lid 8.
(C) Since the plating material of the brazing material 9 is deposited on the annular opening 15 of the masking layer 14, the brazing material 9 can be formed at an accurate position of the metal plate 13.
(D) Moreover, the shape accuracy of the brazing material 9 is remarkably improved as compared with the case of low melting point alloy foil or screen printing.

(E) Since an Au—Sn alloy is used as the plating material, the amount of outgas generated during lid sealing is greatly reduced as compared with the conductive paste.
(F) Since the brazing material 9 is formed in an annular shape, the amount of Au—Sn alloy used can be reduced and the material cost can be reduced.
(G) Moreover, the heat damage given to the electronic component 2 and the case 3 can be reduced by efficiently heating the brazing material 9 when the lid is sealed.
(H) Compared with rolling, the bonding strength of the brazing material 9 to the lid 8 is enhanced.
(Li) Compared with the case of rolling, the lid 5 can be manufactured at low cost with a small-scale facility.

It is a disassembled perspective view of the package which shows one Embodiment of this invention. It is assembly sectional drawing of a package. It is sectional drawing which shows the manufacturing process of a lid. It is a perspective view which shows the metal plate in which many brazing materials were formed by plating. It is a perspective view which shows the metal plate from which the unnecessary part was removed by the etching. It is process drawing explaining a prior art. It is process drawing explaining another prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Package 2 Electronic component 3 Case 4 Opening part 5 Lid 6 Cavity 7 Metallization layer 8 Cover body 9 Brazing material 10 Underlying Ni plating layer 11 Au plating layer 13 Metal plate 14 Masking layer 15 Annular opening 16 Plating electrode 18 Groove 19 Connection part

Claims (6)

  In a package for storing electronic components, a lid that hermetically seals an opening of a case, and includes a metal lid and a brazing material that adheres the lid to the case. A lid for a package, characterized in that it is formed in an annular shape on the periphery of the package.   A method of manufacturing a lid for hermetically sealing a case opening in a package for storing electronic components, wherein a metal plate having a size capable of removing a plurality of the lids is used, and a plurality of annular openings are formed on the surface of the metal plate. A masking layer having a portion is provided, a brazing material is formed on the surface of the metal plate by plating at a portion corresponding to the annular opening, and after removing the masking layer from the metal plate, unnecessary portions of the metal plate are removed, and A method for producing a lid for a package, comprising producing a plurality of lids from a single metal plate.   The manufacturing method of the lid for packages of Claim 2 which used the Au-Sn alloy for the plating material of the said brazing | wax material.   The manufacturing method of the lid for packages of Claim 2 or 3 which removes the unnecessary part of the said metal plate by cutting | disconnection.   The manufacturing method of the lid for packages of Claim 2 or 3 which removes the unnecessary part of the said metal plate by an etching. The package lid according to any one of claims 2 to 5, wherein the organic plate contained in the metal plate and the brazing material is gasified and removed by heating the metal plate before removing unnecessary portions of the metal plate. Manufacturing method.

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