JP2015220749A - Crystal oscillator and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal oscillator that can prevent capacitance variation in the neighborhood of a crystal oscillator circuit and an abnormal operation of the circuit caused by occurrence of noise, and a manufacturing method for the same.SOLUTION: A crystal oscillator in which a crystal piece is mounted on the principal surface of a ceramic base 1 which is rectangular in plan view has a support electrode 3b of a crystal piece formed on the principal surface, through terminals 2b, 2c formed at cut-out portions provided at the four corner portions of the ceramic base 1, a band-shaped insulating film 10 formed inside the outer peripheral edge of the ceramic base 1, and a recessed metal cover having a flange which covers the crystal piece to air-tightly seal the inside. A conductor 11 is formed at a place which can be electrically connected to the two through terminals 2b functioning as GND terminals in the through terminals 2b, 2c and in which no insulation film 10 is formed and to which the metal cover is fixed and sealed. The two through terminals 2b and the metal cover are electrically connected to each other through the conductor 11.

Description

  The present invention relates to a crystal resonator and a manufacturing method thereof, and in particular, a crystal vibration in which a metal cover is bonded to a base formed of an insulator such as ceramic with a conductive resin or the like and a crystal piece is hermetically sealed in the metal cover. In the child, a conductor that electrically connects the GND terminal provided on the outer bottom surface of the base and the metal cover is provided on the sealing surface, so that the capacitance change in the vicinity of the circuit of the crystal unit and the non-use of the circuit due to noise generation are provided. The present invention relates to a crystal resonator that prevents normal operation and a method of manufacturing the same.

  In this type of conventional quartz resonator, as shown in FIGS. 6 and 7, a support electrode lower layer 3a and a connection terminal 2a are formed on an AgPd alloy (silver / palladium alloy) on a surface 1b of a rectangular ceramic base 1 in plan view. ), And at the four corners of the ceramic base 1, through terminals 2 b made of AgPd are formed in castellations (notches) formed of wall surfaces of through holes (through holes) 1 a formed at the time of the sheet-like ceramic fabric. 2c is formed.

  Then, a support electrode lower layer portion 3 a made of an AgPd alloy is formed on the surface 1 b of the ceramic base 1 and is formed under the support electrode 3 b that is connected to the through terminal 2 c and holds the crystal piece 5.

  Further, a support electrode 3b for joining and holding the crystal piece 5 with the conductive resin 7 is formed of AgPd on the upper surface of the support electrode lower layer portion 3a, and a metal cover 6 is formed inside the outer edge portion of the upper surface of the ceramic base 1. A band-shaped insulating film 10 is formed so that the support electrode 3b of the crystal piece 5 is not electrically short-circuited.

  Then, the metal cover 6 is mounted on the upper surface of the insulating film 10 and bonded to the insulating film 10 with an appropriate sealing material such as low melting point glass or thermosetting resin, so that the crystal piece 5 is sealed in the metal cover 6. It is designed to be hermetically sealed.

  Also, normally four mounting terminals 4 are provided at the four corners of the outer bottom surface 1c of the ceramic base 1, and the electrode pattern of the mounting terminals 4 connected to the through terminals 2b, 2c is formed of an AgPd alloy. Here, the mounting terminal 4 connected to the through terminal 2c is an electrode to which a voltage is applied, while the mounting terminal 4 connected to the through terminal 2b is a GND electrode connected to the ground level (Patent Document). 1 and 2).

JP 2013-70357 A JP 2011-211681 A JP 2009-105628 A

  In the base of the resin sealing package in which the metal cover is hermetically sealed with the conductive resin on the base formed of an insulator such as the ceramic material described above, the surface (sealing surface) on which the metal cover is sealed with resin is provided. The conductor for connecting the crystal piece to the external terminal is provided on the same surface. For this reason, when the metal cover is resin-sealed with a conductive resin, the crystal support terminals are electrically short-circuited with the metal cover, so that an insulating layer made of a glass material or the like is formed on the sealing surface.

  Further, in the case of a crystal resonator in which four external terminals are provided on the outer bottom surface of the base, two terminals (NC terminals) not connected to the crystal piece are on the same surface as the sealing surface. It was made not to be arranged in.

  However, when these terminals are arranged on the same surface, as described above, the insulating layer is formed on the upper surface of the base, so that the metal cover is fixed using a conductive resin for sealing. However, the electrical connection with the metal cover could not be made, so that it was not possible to prevent abnormal operation of the circuit due to capacitance change in the vicinity of the circuit of the crystal resonator, noise generation, or the like.

  In such a conventional crystal unit, the metal cover is not electrically connected to the GND terminal. Therefore, when viewed from the circuit side on which such a crystal unit is mounted, the metal cover has a capacitance (C). Or, it is functioning in the same electrical state as the antenna.

  In a crystal resonator using such a resin-encapsulated base, once the crystal resonator is mounted on a circuit board, it can be used, but for example, when a human hand approaches the crystal resonator The circuit formed on the circuit board may not operate or function normally due to a change in capacitance or noise near the circuit.

  Therefore, in order to eliminate such problems, in the seam-sealed crystal resonator, the lid is electrically connected to the GND terminal provided on the outer bottom surface of the ceramic base via the seal ring. (See Patent Document 3).

  The present invention has been made to solve such a problem, and is a crystal resonator in which a crystal piece is mounted on a main surface of a ceramic base having a rectangular shape in plan view, and the crystal resonator is formed on the main surface. Covering the crystal piece, a support electrode for the crystal piece, a through terminal formed in a notch provided at the four corners of the ceramic base, a strip-shaped insulating film formed inside the outer peripheral portion of the ceramic base, and In the quartz crystal resonator comprising a metal cover that hermetically seals the inside, it can be electrically connected to at least one of the through terminals functioning as a GND terminal of the through terminals, and the insulating film is formed. A conductor is provided on a sealing surface where the metal cover is fixed and sealed, so that the GND terminal and the metal cover are electrically connected via the conductor. about About crystal oscillator which is characterized.

  In the present invention, the conductor is formed as a conductive film connected to the two through terminals.

  Furthermore, the present invention provides the method for manufacturing a crystal resonator, wherein a conductor is formed at a location where the insulating film is not formed and where the metal cover is fixed and sealed. It relates to the manufacturing method.

  According to the crystal resonator of the present invention, it is possible to prevent abnormal operation of the circuit due to capacitance change and noise generation in the vicinity of the circuit formed in the crystal resonator.

It is a terminal land connection diagram applied to a crystal resonator which is an embodiment of the crystal resonator of the present invention. It is a top view of the ceramic base which formed the support electrode pattern of the crystal oscillator of this invention. The partial cross section of NC terminal part of a prior art example and the crystal oscillator of this invention is shown, (a) is the partial cross section of the II-II arrow part of the NC terminal part of the prior art example shown in FIG. The partial cross section of the II arrow view part of NC terminal part of this invention shown in FIG. 2 is each shown. It is process drawing of the manufacturing method of the crystal oscillator of this invention. It is a top view of the sheet-like ceramic board | substrate which formed the through-hole and the break line in the sheet-like ceramic fabric used for manufacture of the crystal oscillator of this invention. It is a longitudinal cross-sectional view of the conventional crystal oscillator. It is a top view of the ceramic base in which the support electrode pattern of the conventional crystal oscillator shown in FIG. 6 was formed.

  Hereinafter, embodiments of the crystal resonator according to the present invention will be described with reference to the accompanying drawings.

(Example of crystal unit)
First, FIG. 1 shows a terminal land connection diagram applied to the crystal resonator of the present invention. As shown in FIG. 1, in the crystal resonator in which four mounting terminals are provided on the outer bottom surface of the base, Two of these four mounting terminals are electrically connected to electrodes formed on the crystal piece as connection terminals # 1 and # 3. However, although the remaining two mounting terminals are formed with terminals, they are not connected to the crystal piece and function as GND terminals # 2 and # 4.

  In the crystal resonator according to the present invention, a conductive material is provided at a position where it is connected to the two GND terminals # 2 and # 4 described above, and a metal cover that hermetically seals the crystal piece is provided on the sealing surface. The metal cover and the GND terminals # 2 and # 4 are electrically connected to each other through a conductive resin bonded to the body.

  As in the case of the conventional crystal resonator shown in FIGS. 6 and 7, the crystal resonator of the present invention has a support electrode lower layer portion 3a and a connection terminal 2a on the surface 1b of the ceramic base 1 having a rectangular shape in plan view. A castellation (cutout portion) formed by a wall surface obtained by dividing the through hole (through hole) 1a formed at the four corners of the ceramic base 1 at the time of the sheet-like ceramic fabric into four parts is formed by an AgPd alloy. Through terminals 2b and 2c made of AgPd are respectively formed in the notches.

  Then, on the surface 1b of the ceramic base 1, a support electrode lower layer portion 3a made of an AgPd alloy formed on the lower layer of the support electrode 3b connected to the through terminal 2c and holding the crystal piece 5 is formed.

  Further, a support electrode 3b for joining and holding the crystal piece 5 with the conductive resin 7 is formed on the upper surface of the support electrode lower layer portion 3a with AgPd, and a strip-like insulation is formed inside the outer peripheral portion of the upper surface of the ceramic base 1. A film 10 is formed.

  Then, the metal cover 6 is mounted on the upper surface of the insulating film 10 through a thermosetting conductive resin or a low melting point glass containing high-purity Pb (lead), and the crystal piece 5 is mounted in the metal cover 6. It is designed to be hermetically sealed.

  Here, the melting point of the low-melting glass is usually 600 to 700 ° C., but the melting point varies depending on the additive. The low melting point glass used in the present invention has a melting point of 320 ° C. by adding lead (Pb). Therefore, if the addition amount is small, the low melting point glass is close to an insulator, but the low melting point glass used in the present invention is a conductor because it contains a large amount of lead (Pb).

  Also, four mounting terminals 4 are provided at the four corners of the outer bottom surface 1c of the ceramic base 1, and the electrode pattern of the mounting terminals 4 connected to the through terminals 2b and 2c is formed of an AgPd alloy. Here, the mounting terminal 4 connected to the through terminal 2c functioning as the connection terminals # 1 and # 3 is an electrode to which a voltage is applied, while the mounting terminal 4 connected to the through terminal 2b is at the ground level. It functions as a GND terminal to be connected.

  In the crystal resonator of the present invention, in particular, as shown in FIG. 3B, which is a cross-sectional view taken along the line II in FIG. 2 and FIG. 2, the two through terminals 2b functioning as the GND terminals or these Conductors 11 made of a suitable conductive material are provided at positions electrically connected to the through terminals 2b, respectively, and a conductive adhesive or an entire upper surface of the two conductors 11 and the insulating film 10 are provided. The opening end face of the flange 6a of the metal cover 6 is bonded and joined by the low melting point glass 6c.

  Here, the conductor 11 only needs to be electrically connected to the through terminal functioning as two GND terminals, and any shape may be used. For example, the conductor 11 may be formed as a conductive film at a position where it is electrically connected to the through terminal 2b, or as shown by a chain line in FIG. Alternatively, it may be formed at a position separated from the through terminal 2 b and electrically connected to the metal cover 6. Here, the material of the conductor 11 may be made of a material having high conductivity, for example, an inexpensive material such as copper or a conductive polymer material. There is no need to use expensive materials such as gold and silver.

  Thus, by connecting the conductor 11 to the metal cover 6 via the conductive adhesive or the low melting point glass 6c, the two through terminals 2b functioning as the GND terminals and the metal cover 6 are electrically connected. As a result, it is possible to prevent abnormal operation of the circuit due to capacitance change and noise generation in the vicinity of the circuit of the crystal unit. As a result, good electrical characteristics can be ensured even after the crystal resonator is mounted on the circuit board at the customer site.

On the other hand, in the conventional quartz crystal resonator shown in FIG. 7, even if a conductive resin is used for joining the metal cover 6 to the ceramic base 1, an insulating layer is formed on the sealing surface as described above. Since it is formed, the metal cover 6 and the GND terminal 2b are not electrically connected.
(Example of crystal resonator manufacturing method)
Next, a method for manufacturing a crystal resonator according to the present invention will be described with reference to FIGS.

  As shown in FIG. 4, in the first step (S1) of the method for manufacturing a crystal resonator according to the present invention, first, a sheet-shaped ceramic fabric that forms a sheet-shaped ceramic substrate S on which a large number of ceramic bases 1 can be manufactured is formed. . Next, as shown in FIG. 5, after forming through holes 1a at positions corresponding to the four corners of several hundred individual ceramic bases 1 and cutting lines (break lines) B at the positions connecting the four corners, the sheet The sheet ceramic substrate B is obtained by firing the sheet ceramic dough.

  In the second step (S2), a metal paste of AgPd alloy is printed on a circuit pattern forming surface of each ceramic base 1 of the sheet-like ceramic substrate B using a screen mask to form a circuit pattern.

  In the third step (S3), the circuit pattern formed on each ceramic base 1 is surrounded by a heat-resistant resin or glass paste, with the exception that the conductor is provided in the next step, and is insulated using a screen mask. A film 10 is formed.

  In the fourth step (S4), a conductor 11 made of a suitable conductive material is provided at a location where the insulating film 10 was not formed in the previous step. Usually, a conductive film is formed by printing a metal paste using a screen mask.

  In the fifth step (S5), the support electrode 3b made of AgPd is formed on the circuit formation surface of each ceramic base 1 on which the circuit pattern is formed.

  In the sixth step (S6), the crystal piece 5 is fixedly mounted on the upper surface of the support electrode 3b with the conductive adhesive 7, and is electrically and mechanically connected to the support electrode 3b.

  In the seventh step (S7), the vibration frequency of the crystal piece 5 mounted on each ceramic base 1 of the sheet-like ceramic substrate is measured and adjusted by the mass load effect.

  In the eighth step (S8), the opening end surface (flange surface) of the flange 6a of the metal cover 6 is formed on the insulating film 10 and the conductor 11 corresponding to each ceramic base 1 with a conductive adhesive or low melting point glass 6c. The crystal piece 5 is hermetically sealed in the metal cover 6 by using them.

  In the ninth step (S9), the sheet-like ceramic substrate is divided along a cutting line (break line) to obtain individual crystal resonators.

1. Ceramic base 1a. Through hole 2a. Connection terminal 2b. Through terminal 2c. Through terminal 3a. Support electrode lower layer 3b. 3. Support electrode Mounting terminal 5. Crystal piece6. Metal cover 6a. Flange 6b. Thermosetting resin 6c. 6. Conductive adhesive Conductive resin10. Insulating film 11. Conductor S. Sheet ceramic substrate Cutting line

Claims (3)

  A crystal resonator in which a crystal piece is mounted on a main surface of a ceramic base having a rectangular shape in plan view, the support electrode of the crystal piece formed on the main surface, and notches provided at four corners of the ceramic base A quartz resonator comprising: a through terminal formed on the outer periphery of the ceramic base; a band-shaped insulating film formed on an inner periphery of the ceramic base; and a metal cover that covers the crystal piece and hermetically seals the inside. A sealing surface that can be electrically connected to at least one of the through terminals functioning as a GND terminal of the terminals and that is not formed with the insulating film and to which the metal cover is fixed and sealed A crystal resonator, wherein a conductor is provided so that the GND terminal and the metal cover are electrically connected via the conductor.   The crystal unit according to claim 1, wherein the conductor is formed as a conductive film connected to the through terminal.   3. The crystal resonator manufacturing method according to claim 1, wherein a conductor is formed at a location where the insulating film is not formed and where the metal cover is fixed and sealed. Child manufacturing method.