JP2008300497A - Sealing method for package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the lifting of a lid in the case of the seam-joining of a package, and improve the airtightness of the sealing of the package. <P>SOLUTION: With respect to a sealing method for packages wherein a rectangular lid 2 is so mounted on the opening portion of a package 1 for storing therein an electronic component and a current application is so performed between a pair of roller electrodes 3a, 3b while contacting them in a rolling way with one opposing two sides of the lid 2 as to seam-join the one opposing two sides of the lid 2 to the package 1, after a first joining operation for seam-joining the one opposing two sides of the lid 2 to the package 1, a second joining operation for seam-joining the other opposing two sides of the lid 2 to the package 1 is performed. and after ending the current application of the second joining operation, the pressing operations of the roller electrodes 3a, 3b to the lid 2 are maintained during a predetermined time, and further, after solidifying the remelt of the joining portion joined by the first joining operation, the roller electrodes 3a, 3b are separated from the lid 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a package sealing method in which a lid, which is a metal lid plate, is seam-bonded to an opening of a package containing electronic components such as a crystal resonator and a surface acoustic wave filter.

  Conventionally, a parallel seam bonding method has been widely used as a method for hermetically sealing electronic components such as a crystal resonator and a surface acoustic wave filter in a package. FIG. 4 is a cross-sectional view of a conventional package with a seal ring. First, an electronic component 54 such as a crystal resonator is accommodated in a package 53 formed by brazing a metal seal ring 52 to a ceramic substrate 51. A component 54 that is electrically connected to the outer lead 56 by a wire 55 is prepared. A lid 57 made of Kovar or the like is positioned and placed in the opening of the package 53.

  At this time, in order to avoid the positional displacement by some external force until the positioned lid 57 is seam-joined or the roller electrode is contacted to start the seam joining, The lid is usually temporarily fixed by spot bonding.

  This temporary fixing is generally performed with roller electrodes for seam joining for reasons of workability. As shown in FIG. 5A, two opposing sides of the lid 57, for example, two sides on the long side are provided. A pair of tapered roller electrodes 58a and 58b are brought into contact with each other at a substantially central portion, and electricity is applied between the electrodes without rolling, and the roller electrodes 58a and 58b are lifted and separated from the lid 57 as they are.

  Then, as shown in FIG. 5B, the roller electrodes 58a and 58b are brought into contact with one end edge a of the long side of the lid 57 under a certain pressure condition, and the package 53 is placed in this state. At the same time as the stage 59 is moved in the direction of arrow A, pulsation energization is performed on the roller electrodes 58 a and 58 b, the long side is melted by the Joule heat generated at this time, and the lid 57 is seam joined to the package 53.

  When the long-side seam joining is thus completed, the roller electrodes 58a and 58b are once moved upward to adjust the electrode interval, and the package 53 is rotated by 90 ° in the horizontal plane as shown in FIG. 5C. . Thereafter, the roller electrodes 58a and 58b are lowered again, and the other two opposite sides, that is, the short sides are similarly seam-joined to complete the sealing.

  Here, at least the lower surface of the base material made of Kovar or the like of the lid 57 is generally plated with Ni, and the seal ring 52 is also made of the base material made of Kovar or the like with Au plating of Ni base. Yes. Since the Ni plating and the Ni plating Au plating function as a brazing material at the time of joining, the base material of the lid 57 and the base material of the seal ring 52 are actually joined with little melting.

  In such operation of the roller electrode, the roller electrode and the lid may be welded when the roller electrode has finished rolling contact on the two opposite sides of the lid. The problem of floating up occurs. Therefore, as disclosed in Patent Document 1, there is a method of avoiding the problem due to welding by rolling a small distance in the direction opposite to the rolling performed together with energization before raising the roller electrode and then raising the roller electrode. It has been adopted.

  In addition to the package with a seal ring as described above, in recent years, a sealing structure using a package without a seal ring has become widespread, and this seam joining method is generally referred to as a seal ringless seam method or a direct seam method. (Hereinafter, this seam joining method is referred to as a direct seam method). This direct seam method has been widely adopted because the entire package can be reduced in height because the seal ring is not used, and the cost of the package can be reduced.

  The basic structure of the direct seam method is disclosed in Patent Document 2, which will be described with reference to FIG. Only the metallized layer 62 is formed on the periphery of the opening of the package 61 without providing a seal ring, and the metallized layer 62 is plated with Au as a Ni base.

  Here, this metallized layer can be formed at the same time in the process of forming electrodes and wiring patterns on a ceramic package, and in order to braze the seal ring to the package even in a package with a seal ring. It has been formed. Further, the internal structure of the package 63 configured in this way is the same as that of the package with the seal ring described above, and the description thereof is omitted.

  Further, a Ni plating layer 65 is formed on the lower surface of the lid 64 disposed in the opening of the package 63, and by performing parallel seam bonding using a roller electrode, the Ni plating layer 65 and the periphery of the package opening are formed. The plating layer is melted to become a brazing material, and sealing is performed.

  Furthermore, the recent direct seam method has shifted to a method in which a brazing filler metal layer 66 made of Ag—Cu alloy or Au—Sn alloy is clad on the lower surface of the lid 64 as shown in FIG. ing. This transition is intended to relieve stress due to the difference in thermal expansion coefficient between the package and the lid, which has been a problem in the past, and absorbs the stress by eliminating the seal ring. Since this stress becomes a problem more than before, in order to lower the bonding temperature and reduce the generation of stress itself, instead of Ni having a high melting point of about 1450 ° C., the melting point of about 780 ° C. A brazing material layer made of a low Ag—Cu alloy and an Au—Sn alloy having a melting point of about 280 ° C. is employed.

JP-A-6-224315 (second page, FIG. 1) JP 2006-114710 A (page 3, FIG. 7)

  However, the inventors have found that the following problems occur when parallel seam bonding is performed by a conventional method using a direct seam method as described above, particularly a low melting point brazing filler metal. This problem will be described with reference to FIGS. FIG. 7 is a plan view when a sealing operation similar to the seam joining step described in FIG. 5 is performed using a package without a seal ring and a lid in which a brazing material of Au—Sn alloy is clad on a base material. is there.

  In FIG. 7, reference numeral 61 denotes a package for the direct seam method in which a seal ring is not provided as described above, and a metallized layer and a Ni base Au plating applied thereto are formed on the periphery of the opening. Reference numeral 68 denotes a lid, which is obtained by clad and punching a base material made of Kovar and a metal layer made of an Au—Sn alloy having a low melting point among metals used as a brazing filler metal.

  Here, FIG. 7 shows the upper surface of the package in a state where the two opposite sides C and D have already been joined and the other two opposite sides E and F have reached the joining end point. (Hereinafter, the first two joints facing each other will be referred to as a 1st seam, and the second joint between two opposite sides will be referred to as a 2nd seam.) Then, when the energization is stopped and the roller electrode is immediately raised in the state of FIG. Or, as described above, in order to peel off the welding between the roller electrode and the lid, when the roller electrode is raised after performing a minute distance rolling operation in the direction opposite to the previous rolling contact immediately after stopping energization, Since the roller electrode is raised in a state where both ends of the side D joined by the 1st seam are remelted by the heat generated by the 2nd seam, a peeling phenomenon occurs in the remelted portion as shown in FIG. 8, and the lid slightly floats. Further, the airtightness of the sealing may be deteriorated due to the gap in the remelted portion generated by the float.

  In order to solve such a problem, the present invention provides a parallel seam joining method that does not impair the confidentiality of sealing even when the end of the joint formed by the first seam is remelted at the end of the 2nd seam. It is.

  As a first aspect of the present invention, a rectangular lid is placed in an opening of a package for storing electronic components, and a pair of roller electrodes are rolled on two opposite sides of the lid, and electricity is applied between both electrodes. In the package sealing method in which the two sides are seam-bonded to the package, the 2nd seam is performed after the first seam, and the energization in the bonding operation of the 2nd seam is completed, and the pressure on the lid by the roller electrode is maintained for a certain time. In addition, the present invention provides a package sealing method characterized in that after the remelting of the joint portion joined at the first seam is solidified, the roller electrode is separated from the lid.

  According to a second aspect of the present invention, the pressing for maintaining the predetermined time is performed in a state where the extension of the rotation axis center line of the roller electrode is positioned outside the outer edge of the lid as viewed from above. The package sealing method described as the first aspect is provided.

  Further, according to a third aspect of the present invention, in the 2nd seam, after the pressure on the lid by the roller electrode is maintained for a certain time, the roller electrode is rolled for a minute distance in the direction opposite to the joining operation of the 2nd seam, and thereafter The method for sealing a package according to either the first aspect or the second aspect is characterized in that the package is separated from the lid.

  According to the present invention, heat can be absorbed while pressing the lid until the joint of the 1st seam that has been remelted when the energization of the 2nd seam is stopped, so that the joint of the remelted portion is peeled off. The lid does not float up and the sealing hermeticity does not deteriorate.

  In addition, by pressing the lid for a certain period of time after stopping the energization in a state where the extension of the rotation axis center line of the roller electrode is located outside the outer edge of the lid as viewed from above, In this case, since the roller electrode presses the lid directly above the joint portion of the remelted first seam, the endothermic effect is increased, and the predetermined time can be shortened.

  In addition, immediately after the 2nd seam is completed, heat is absorbed while maintaining the pressure for a certain period of time without being rolled for a short distance in the direction opposite to the previous rolling, so that the lid floats due to remelting of the 1st seam joint. Can be prevented.

  Next, an embodiment of a package sealing method according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view for explaining a parallel seam joining process according to the present invention. In FIG. 1, 1 is a package, 2 is a lid, 3a and 3b are a pair of roller electrodes. This package 1 is made of ceramic, and a metallized layer is formed on the periphery of an opening (not shown) without providing a seal ring, and this is plated with Au as a Ni base.

  The lid 2 is formed by cladding and punching a base material 4 made of Kovar and a brazing material 5 made of Au—Sn alloy. The thickness of the base material 4 is 70 μm, and the thickness of the brazing material 5 is It is 30 μm. The lid 2 used in this embodiment is a rectangular plate material having a long side of 3 mm and a short side of 1.5 mm, and the four corners have a slight R finish.

  FIG. 1A shows a state in which spot bonding for temporary fixing has already been performed and the first seam of seam bonding, which is the main bonding, is about to be performed. First, the pair of roller electrodes 3a and 3b are brought into contact with one end of two opposing sides of the lid 2, and the lid 2 is pressed with a predetermined pressing force. Then, the roller electrodes 3a and 3b are brought into rolling contact with each other in the direction of the arrow and energized between both electrodes, that is, 1st seam is performed. This energization is performed by a seam-joining power source, and a current-controlled pulse current flows between both electrodes with the energization and rest periods also controlled.

  Next, as shown in FIG. 1B, the direction of the roller electrodes 3a, 3b or the package 1 is rotated by 90 ° in the horizontal direction, and the remaining two seams joined, that is, 2nd seam is performed. In this way, the four sides of the lid 2 are seam-bonded to the package and sealing is performed. By performing this operation in an inert gas environment or a vacuum environment, the inside of the package after sealing is sealed in an inert gas environment or It is also possible to maintain a vacuum environment.

  Next, FIG. 1C shows a state in which the roller electrode reaches the end point of the 2nd seam and the energization is stopped. However, even if the energization is stopped, the lid is not lifted for a certain time. Maintain the pressure on. Originally, this roller electrode is intended to generate Joule heat in the seam-joined object, so the electrical resistance of the electrode itself is kept as low as possible, its own heat generation is small, and conversely the heat capacity is the object of seam welding. The first seam brazing material remelted at the end of the 2nd seam is absorbed by the roller electrode and solidifies. In this embodiment, after the energization is stopped, solidification of the remelted portion is completed by maintaining the pressure for 0.5 seconds on the spot.

  In addition, when the four corners of the lid are R-finished as in this embodiment, the center line of the rotation axis of the roller electrode is set to the lid as shown in FIG. 2A regardless of the energization stop position. In the state where it is positioned outside the outer shape, the same pressing as described above is maintained. This positional relationship is indicated by a symbol L in FIG. 2 (a) which is a plan view and FIG. 2 (b) which is a side view thereof. Since the roller electrode is tapered, the contact point between the roller electrode and the lid is The cooling time can be further shortened by going directly above the remelted portion of the 1st seam.

  Further, after maintaining the pressing for a certain time (0.5 seconds in this embodiment) as described above, the roller electrode may be raised as shown in FIG. If there is a risk of welding with the lid, as shown in FIG. 3 (b), once the roller electrode is rolled for a short distance in the direction opposite to the rolling direction for seam welding, the weld is peeled off. It may be raised.

The perspective view which shows embodiment of this invention The top view and side view which show embodiment of this invention Side view showing an embodiment of the present invention Sectional view showing conventional technology Plan view showing conventional technology Sectional view showing conventional technology Plan view showing conventional technology Side view showing conventional technology

Explanation of symbols

1, 51, 61 Package 2, 57, 64, 67, 68 Lid 3a, 3b, 58a, 58b Roller electrode 4 Base material 5 Brazing material 52 Seal ring 53 Package 54 Electronic component 55 Wire 56 Outer lead 59 Stage

Claims (3)

A rectangular lid is placed in the opening of the package that stores the electronic components, and a pair of roller electrodes are energized between the two opposite sides of the lid while energizing between the two electrodes, and the two sides are seam bonded to the package. In the package sealing method, the first joining operation for seam joining one opposing two sides is followed by the second joining operation for seam joining the other two opposing sides, in the second joining operation. After the energization is completed, the pressure on the lid by the roller electrode is maintained for a certain period of time, and after the remelting of the joined portion joined in the first joining operation is solidified, the previous roller electrode is separated from the previous lid. And a package sealing method. 2. The package sealing according to claim 1, wherein the pressing for maintaining the predetermined time is performed in a state in which an extension of a rotation axis center line of the roller electrode is positioned outside an outer edge of the lid as viewed from above. Stop method. In the second joining operation, the roller electrode is kept pressed against the lid for a certain period of time, and then the roller electrode is brought into a small distance rolling contact in the direction opposite to the second joining operation, and then separated from the lid. The package sealing method according to claim 1 or 2.

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