JPH07326929A - Crystal oscillator - Google Patents

Abstract

PURPOSE:To make an oscillation circuit board capable of coping with automatized manufacture and to provide an inexpensive crystal oscillator for which the various kinds of joining reliability is high by burying a part of a lead frame in a resin substrate and forming the oscillation circuit board. CONSTITUTION:The oscillation circuit board to which a crystal oscillator 2 and an IC chip 3 are mounted is housed inside an air-tight container 4. For the oscillation circuit board, a part of the lead part 11 of the lead frame is buried in the resin substrate 12 and a chip mounting part 11a, IC connection parts 11b-11f, crystal oscillator connection parts 11g and 11h and lead terminal connection parts 11i-11b are defined. Thus, since the lead part 11 of the oscillation circuit board is a conductor formed by being cut off from the lead frame, the joining reliability with the IC chip 3 and the joining reliability with the supporting members 2a and 2b of the crystal oscillator 2 and the lead terminal 43 are improved compared with a normal thick film conductor pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillator circuit board in which a predetermined circuit conductor is formed in a hermetically sealed container by using a lead frame of a predetermined shape, a crystal oscillator mounted on the oscillator circuit board, an IC chip, etc. The present invention relates to a crystal oscillator accommodating electronic components of.

[0002]

2. Description of the Related Art Crystal oscillators are widely used in electronic equipment, communication equipment and the like. As an example of a conventional crystal oscillator, as shown in FIG. 9, a predetermined thick film wiring pattern 9 serving as a predetermined circuit conductor is formed on a ceramic substrate 91a in an airtight container 90 including a can case 90a and a stem substrate 90b.
The circuit board 91 on which 1b is formed, the crystal resonator 92 arranged on the circuit board 91, the IC chip 93, and the like are housed.

The airtight container 90 is formed by hermetically sealing the stem substrate 90b and the can case 90a by resistance welding or the like, and the stem substrate 90b extends from the inside of the container to a plurality of lead terminals 94. ... has been planted.

The circuit board 91 is, for example, a ceramic board 9.
1a and a predetermined circuit conductor including a placement pad of IC chip 93, a connection pad, a bonding pad for a crystal resonator support, and a lead terminal bonding pad by a thick film method using Ag-based conductor paste on this substrate 91a. The wiring pattern 91b is formed.

The IC chip 93 is placed on the IC chip placement pad.
, A crystal oscillator support member 92a connected by wire bonding to the IC chip 93 to the connection pad, and connected to the crystal oscillator support member connection pad so that the crystal oscillator 92 straddles, 92b is joined, and the lead terminal connection pad is soldered to the above-mentioned lead terminal 94.

[0006]

However, in forming the circuit board 91 in the above-mentioned oscillator, the wiring of a predetermined shape is formed on the surface of the large-sized ceramic substrate on which the dividing groove is formed by screen printing of the conductive paste. The pattern 91b is printed, printed, and then divided into the shapes of the individual circuit boards 91 along the dividing grooves. In the manufacture of such a circuit board 91, it seems that it is excellent in productivity, but it is actually unnecessary for forming the wiring pattern 91b, for position control of screen printing, and for dividing from a large ceramic board. It was necessary to control division so that cracks would not occur.

Further, in order to improve the bonding reliability of the wire bonding between the IC chip 93 and the connection pad, it is necessary to sufficiently consider the layer structure of the wiring pattern 91b. After the formation, it was necessary to subject the surface of the underlying conductor film to Au plating.

Furthermore, when the lead terminal 94 and the lead terminal connection pad are soldered, the wiring pattern 91b may be eroded by soldering, regardless of the presence or absence of the Au plating layer. Was difficult. That is, in the above-mentioned circuit board 91, productivity is low when yield is taken into consideration, manufacturing becomes complicated, and automated manufacturing is difficult, and as a result, the cost of the entire oscillator increases.

The present invention has been devised in view of the above-mentioned problems, and an object thereof is to provide a circuit board with a structure that can be adapted to automated manufacturing, and to provide a highly reliable joint at various connection portions and to reduce the cost. To provide a simple crystal oscillator.

[0010]

According to the present invention, in a crystal oscillator in which an oscillation circuit board on which at least a crystal oscillator and an IC chip are mounted is housed in an airtight container, the oscillation circuit board is desired. A crystal oscillator in which a part of a shaped lead frame member is embedded in a resin substrate.

[0011]

According to the present invention, a conductor (lead portion) forming a predetermined circuit of the oscillator circuit board is formed by cutting a lead frame by burying a part of the lead frame of a desired shape in the resin board. It is integrated with the resin substrate.

Therefore, even if a lead terminal or the like is joined to the lead portion by solder joining, solder erosion does not occur, and a highly reliable connection is possible. In addition, it is easy to preliminarily apply various platings to the entire surface of the lead frame, so that, for example, the IC chip and the lead portion can be connected easily and firmly by wire bonding. A reliable connection is possible.

Further, since a lead frame having a predetermined shape is molded with resin and then the lead frame is cut to form a circuit board, a crystal oscillator, an IC chip or the like is mounted on the lead frame. All can be done before cutting and separating from, and can easily support automated manufacturing, and complicated control such as printing processing, plating processing, division processing on a large ceramic substrate as in the past, and strict control is required Since the process is not required, the circuit board can be formed at a low cost, which results in an inexpensive crystal oscillator.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The crystal oscillator of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional structural view of a crystal oscillator of the present invention, FIG. 2 is a side view with a can case omitted, FIG. 3 is a plan view of the same, and FIG. 4 is a crystal oscillator, an IC.
FIG. 3 is an external perspective view of an oscillator circuit board on which a chip is mounted.

In the figure, a crystal oscillator 10 is mainly composed of an oscillation circuit board 1, a crystal oscillator 2, an IC chip 3, and an airtight container 4.

The oscillator circuit board 1 is cut from a predetermined desired lead frame member to form a predetermined circuit conductor, and the lead portion 1 is formed.
1 and a resin substrate 12 in which a part of the lead portion 11 is embedded.

The lead portion 11 is made of, for example, phosphor bronze or SU.
The surface of a metal flat plate member such as S, Kovar, 42 alloy, nickel silver, etc. is entirely or selectively coated with, for example, plating of gold, silver or the like. The plating treatment is performed in the state of a flat metal plate or by pressing the flat metal plate into a predetermined shape and then collectively performing the plating.

The lead portion 11 which is the lead frame
Is at least the portions 11a to 11h connected to the crystal unit 2 and the IC chip 3, and the portion 1 connected to the lead terminal 43.
1i to 11l, and is molded on the resin substrate 12 so that the respective connection portions 11a to 11l are exposed. 1
1a is a chip mounting portion, 11b to 11f are IC connecting portions, 1
1g and 11h are called a crystal oscillator connecting part, and 11i to 11l are called lead terminal connecting parts.

The resin substrate 12 is made of a heat-resistant resin such as liquid crystal polymer and epoxy resin, and is made of resin by using an upper die and a lower die so as to be integrated with a lead frame press-molded into a predetermined shape. The lower base plate 12a and the ring-shaped frame 12b integrally formed on the lower base plate 12a.

On the surface of the lower base plate 12a surrounded by the ring-shaped frame 12b, the chip mounting portion 11a,
The IC connecting portions 11a to 11f are exposed, the IC chip 3 is arranged on the chip mounting portion 11a, and the IC connecting portion 1 is provided.
The electrodes 1b to 11f are connected to the electrodes of the IC chip 3 via wire bonding or the like.

Further, on the surface of the lower base plate 12a on the outer periphery of the ring-shaped frame body 12b, the crystal unit connecting portions 11g.
11h is exposed, and the crystal unit 2 is indirectly mounted. That is, indirectly mounting means, for example, the crystal unit 2
Means that the operation is performed via the crystal oscillator support members 2a and 2b.

Lead terminal connecting portions 11i to 11l project from the side surface of the resin substrate 12 and extend in the longitudinal direction of the resin substrate 12. The connecting portions 11i to 11l are each connected to the lead terminal 43.

The crystal oscillator 2 has vibrating electrodes on both principal surfaces of a disk-shaped or strip-shaped crystal piece cut in a predetermined direction and a predetermined thickness from a raw quartz crystal so as to have a predetermined vibration mode and a predetermined frequency. And an extraction electrode is formed.

In the embodiment shown in FIG. 1, the crystal unit 2 is
Oscillation circuit board 1 through crystal unit support members 2a and 2b
Is joined to the lead portion 11. Specifically, the crystal unit 2 is mounted on the upper surface of the crystal unit support members 2a and 2b formed into a substantially Z shape by bending a flat plate member such as SUS, nickel silver, phosphor bronze or the like. Then, the extraction electrode of the crystal unit 2 and the crystal unit support members 2a and 2b are joined by a conductive adhesive. Then, the bottom surfaces of the crystal unit support members 2a and 2b have crystal unit connecting portions 111g,
It is joined to 11h via a conductive adhesive material,
The electrical connection between the crystal unit 2 and the lead portion 11 is achieved.

The IC chip 3 has a chip mounting portion 11
It is directly bonded to a and is electrically connected between the electrodes of the IC chip 3 and the IC connecting portions 11b to 11e by wire bonding.

The oscillation circuit board 1 on which the crystal oscillator 2 and the IC chip 3 are mounted is bonded and placed on the stem substrate 41 of the airtight container 4.

The airtight container 4 comprises, for example, a metal stem substrate 41 and a can case 42, both of which are hermetically sealed by resistance welding or the like to form the container. Incidentally, lead terminals 43 ... Are planted in the stem substrate 41.

On the inner surface of the stem substrate 41 as described above, the oscillator circuit substrate 1 in which the crystal unit 2 and the IC chip 3 are bonded is arranged as shown in FIGS. 2 and 3, and the stem substrate 4 is arranged.
1 and the lead terminals 43 ... and the oscillator circuit board 1
Are electrically connected to the lead terminal connecting portions 11i to 11l by a conductive adhesive material such as solder or resistance welding, and are mechanically and firmly joined.

The characteristic of the present invention is that the oscillator circuit board 1 is used.
Is composed of a resin substrate 12 in which a part of the lead portion 11 which is a lead frame is embedded, and the conductor forming a predetermined circuit is formed by the lead portion 11.

That is, a part of the lead portion 11 serves as a chip mounting portion 11a on which an IC chip or the like is mounted, similarly IC connecting portions 11b to 11f, and crystal oscillator connecting portions 11g, 11h, Lead terminal connection parts 11i to 11
It has become l.

The IC mounting portion 11a is integrated with a lead terminal connecting portion 11k extending outside the resin substrate 12. The lead terminal connecting portion 11k is connected to the lead terminal 43 of the VDD terminal, for example.

The IC connecting portions 11b to 11f are portions to be joined by wire bonding from the electrodes of the IC chip. In particular, the connecting portions 11b and 11c are exposed to the outside of the frame body 12b of the resin substrate 12 and the crystal oscillator. Connection part 11g, 11
It is integrated with h. The connecting portions 11d to 11f extend to the outside of the resin substrate 12, and the connecting portion 11d is integrated with the lead terminal connecting portion 11i. The lead terminal connecting portion 11i is connected to the lead terminal 43 of the control terminal, for example. The connecting portion 11e is the lead terminal connecting portion 11
It is integrated with j. This lead terminal connecting portion 11j
Is connected to the lead terminal 43 of the GND terminal, for example. The connecting portion 11f is integrated with the lead terminal connecting portion 11l. The lead terminal connecting portion 11l is connected to, for example, the lead terminal 43 of the output terminal.

The lead terminal connecting portions 11i to 11l are cut and raised so as to be orthogonal to the spreading plane of the lead portion 11. If the oscillator circuit board 1 is mounted and joined to the stem substrate 41, four lead terminals 43 are formed. .. comes into contact with or comes close to the main surfaces of the lead terminal connecting portions 11i to 11l.

As described above, since the lead portion 11 of the oscillator circuit board 1 is a conductor formed by cutting from the lead frame, it is compared with the thick film conductor film pattern formed by the conventional thick film method. Then, the bonding reliability with the IC chip 3, the bonding reliability with the crystal resonator supporting members 2a and 2b of the crystal resonator 2, and the bonding reliability with the lead terminal 43 are improved. That is, the thick conductor film 91b of the conventional oscillator circuit board 91
In comparison with the above, the lead frame has a higher bonding strength itself for wire bonding, and for example, it is possible to easily perform Au plating on the surface in the state of the hoop material that forms the lead frame. The joining reliability is dramatically improved. Further, when the crystal unit supporting members 2a and 2b and the lead terminal 43 are joined by soldering, solder erosion or the like does not occur at all from the lead frame to the lead portion 11, and a circuit conductor is formed by a thick conductor film. Both joining work and joining reliability can be dramatically improved compared to the product.

Next, the manufacturing process of the oscillator circuit board 1 will be described with reference to FIG.

First, as shown in FIG. 6A, from a hoop material in which, for example, an Au plating layer, a silver plating layer or the like is attached to the surface of a metal member such as phosphor bronze, SUS, Kovar, 42 alloy, nickel silver, etc. The lead frame body 60 having a predetermined shape is formed by press molding. The lead frame body 60 includes a frame portion 62 and a lead portion 61 remaining when the frame portion 62 is cut, and the lead portion 61 finally becomes the lead portion 11.

In FIG. 6 (a), reference numerals 61j to 61l are portions that will eventually become the lead terminal connecting portions 11i to 11l.

Next, as shown in FIG. 6B, the resin substrate 12 is formed at a predetermined position of the lead frame body 60. Specifically, a predetermined position of the lead frame body 60 is sandwiched by an upper mold and a lower mold that define the shape of the resin substrate 12, and a resin is molded in a space between the upper mold and the lower mold. Then, the resin is cured. In FIG. 6B, the one-dot chain line portion X is a cutting line in the next step, and the two-dot chain line portion Y is a bending line in the next step.

Next, as shown in FIG. 6 (c), by press molding, cutting is performed at the one-dot chain line portion X and bending is performed at the two-dot chain line portion Y. As a result, the main surfaces of the lead portions 61j to 61l are planes that are substantially orthogonal to the plane direction of the lead frame body 60. Even when cut along the line X, the respective lead portions 61 are integrated by the resin substrate 12, and the resin substrate 12 further includes the lead portions 61j to 6j.
The lead portions 61 and the resin substrate 12 are not separated from the frame portion 62 individually because they are connected to the frame portion 62 by 1l.

After that, the IC chip 3 is bonded and mounted on a portion of the lead portion 11 which will eventually become the chip mounting portion 11a.
Wire bonding bonding is performed between the electrodes of the C chip 3 and the portions to be the IC connecting portions 11b to 11f, and the crystal oscillator 2 arranged so as to straddle over the crystal oscillator support members 2a and 2b. , The crystal oscillator supporting members 2a and 2b, and the portions to be the crystal oscillator connecting portions 11g and 11h. According to the above process, the lead frame body 60
Since each of the above-mentioned processes can be performed in a flow operation on the plurality of resin substrates 12 held by, the productivity is improved, and the automated manufacturing is possible.

Now, the final step of the oscillation circuit board 1 is a step of cutting the lead portions 61i to 61l to separate each oscillation circuit board 1 from the frame portion 62.

There are basically two types of cutting, one of which is to cut along the cutting lines Z and Z ₁ shown in FIG. 6 (c). This is the oscillator circuit board 2 shown in FIGS.

The first one is the cutting lines Z and Z ₂ shown in FIG. 6 (c).
It will be cut with. This is achieved by the oscillator circuit board 1 shown in FIGS.

That is, according to the oscillator circuit board 1 cut along the cutting lines Z and Z ₂ , especially the lead terminal connecting portions 11j and 11l.
Is much longer than the lead terminal connecting portions 11j and 11l of the oscillation circuit board ₁ which are cut along the cutting lines Z and Z1.

The lead terminals 11i to 11l including the lead connecting portions 11j and 11l are in contact with or close to the lead terminals 43 ... Implanted in the stem substrate 41 as described above. In the oscillation circuit board 1 cut along the cutting lines Z and Z ₁ , for example, the lead terminal 4 that abuts the lead connection portion 11i.
If 3 and the distance between the lead terminals 43 in contact with the lead connecting portion 11j is a unit width, the cutting line Z, in the oscillator circuit board 1 is cut at Z _2, for example lead terminal connecting portions 11i
The distance between the lead terminal 43 that abuts on the lead terminal 43 and the lead terminal 43 that abuts on the lead connecting portion 11j is twice the unit width.

That is, depending on the cutting positions of the lead portions 61i, 61l corresponding to the lead terminal connecting portions 11i, 11l,
It is possible to arbitrarily control the interval between the lead terminals 43 described above.

For example, the oscillators shown in FIGS. 1 to 4 have half-inch size lead terminal intervals, and the oscillators shown in FIGS. 7 and 8 have inch-size lead terminal intervals.

That is, the circuit portion of the oscillator circuit board 1 is cut from the lead frame body 60 having a predetermined shape.
As a result, the reliability of various joints is improved, and it is possible to improve productivity and cope with automated manufacturing. As a result, cost reduction is achieved and the shape of the lead portion 61 is
Depending on the cutting position, an oscillator having an arbitrary lead terminal size can be easily dealt with and the versatility is excellent.

On the other hand, in the conventional oscillator,
Since the circuit board 91 is made of the ceramic board 91a,
In order to control the width between the lead terminals 94, it is necessary to fundamentally change the shape of the ceramic substrate 91a, and it is necessary to prepare the ceramic substrate 91 corresponding to the width between the lead terminals 94. Was there.

Further, although not shown, parts of the crystal unit connecting portions 11g and 11h of the lead portion 11 shown in FIG. 5 are not buried in the resin substrate 12 but are raised by a bending process, and the tip ends thereof are made horizontal. If the bending process is performed so that the lead portion 11 integrated with the resin substrate 12
A supporting member for directly mounting the crystal unit 2 can be formed. By doing so, the crystal unit supporting member 2a,
Compared with the case of joining to the lead portion 11 via 2b,
Since the number of joints is reduced, the joint reliability is improved, which is desirable in terms of characteristics.

In the above embodiment, the bare chip connected by wire bonding is used as the IC chip 3, but the IC chip may be an IC sealed in a package. Further, as the IC chip 3, the IC chip alone in which the feedback resistance and the load capacitance are integrated has been described, but only the inverter is formed in the IC chip, and the electronic parts such as the chip capacitor and the chip resistor are connected to the lead portion as necessary. You may perform joining etc. In this case, the shape and arrangement of the lead portion 11 are naturally changed.

Further, the stem substrate 4 is used as the airtight container 4.
Although the container including 1 and the can case has been described, a ceramic package or the like may be used.

[0053]

As described above, according to the present invention, even when the oscillator circuit board and the lead terminal are solder-joined, the lead portion is a member cut from the lead frame body having a predetermined shape. Highly reliable, because the lead frame is formed by resin molding, productivity is improved, automated manufacturing can be easily supported, and any standard lead terminal spacing can be easily supported. It becomes a crystal oscillator with excellent versatility.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a cross-sectional structure of a crystal oscillator of the present invention.

FIG. 2 is a side view of the crystal oscillator of the present invention with a can case omitted.

FIG. 3 is a plan view of a crystal oscillator according to the present invention with a can case omitted.

FIG. 4 is an external perspective view of an oscillator circuit board including a crystal oscillator and an IC chip of the crystal oscillator of the present invention.

FIG. 5 is an external perspective view of an oscillator circuit board of a crystal oscillator according to the present invention.

6A to 6C are plan views for explaining the manufacturing process of the oscillation circuit board.

FIG. 7 is a side view of another crystal oscillator according to the present invention with a can case omitted.

FIG. 8 is a plan view of a crystal oscillator according to another embodiment of the present invention with a can case omitted.

FIG. 9 is a schematic view showing a cross-sectional structure of a conventional crystal oscillator.

[Explanation of symbols]

 10: Crystal oscillator 1: Oscillation circuit board 2: Crystal oscillator 2a, 2b: Crystal Vibration support member 3 ... IC chip 4 ... Airtight container 11 ... Lead part 12 ... ..Resin substrate 60 ... lead frame body 61 ... lead portion 62 ... frame portion

Claims (1)

[Claims] 1. A crystal oscillator in which an oscillation circuit board on which at least a crystal oscillator and an IC chip are mounted is housed in an airtight container, wherein the oscillation circuit board is formed by resin-forming a part of a lead frame member having a desired shape. A crystal oscillator characterized by being embedded in a substrate.