JP2002330027A - Temperature compensated crystal oscillator for surface mounting - Google Patents

Abstract

(57) [Abstract] [Object] It is an object of the present invention to provide a temperature-compensated oscillator for surface mounting which is particularly suitable for reduction in height and has improved productivity and reliability. A flat terminal plate having a plurality of lead terminals is provided, an IC chip is arranged on the other surface of the flat terminal plate, and each lead terminal is directly connected to a plurality of terminal electrodes of the IC chip. A quartz oscillator is arranged on one surface side of the flat terminal plate, and the lead terminals connected to the crystal terminal electrodes of the IC chip are directly connected to the mounting electrodes of the quartz oscillator, and the IC chip is resin-molded. The lead terminals connected to the power, output and ground terminal electrodes are bent from the side to the bottom of the resin mold as mounting terminals for surface mounting.
A lead terminal for writing compensation data connected to the temperature compensation mechanism of the C chip is bent on the side surface of the crystal unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature-compensated crystal oscillator for surface mounting (referred to as a temperature-compensated oscillator) as an industrial technical field, and more particularly to a temperature-compensated oscillator which has been downsized.

(Background of the Invention) A temperature-compensated oscillator is used for a mobile phone or the like used in a dynamic environment because the oscillation frequency is stable with respect to a temperature change. In recent years, miniaturization has been intensified, and a reduction in height as well as a planar outer shape has been required.

FIG. 4 is a schematic view of a temperature-compensated oscillator for explaining a conventional example. The temperature-compensated oscillator includes a crystal oscillation circuit 1 and a temperature compensation mechanism 2. The crystal oscillation circuit 1 includes a crystal resonator 3 and an oscillation circuit 4. The temperature compensation mechanism 2 applies a compensation voltage from a compensation voltage generation circuit (not shown) to the voltage variable capacitance element 5 inserted in the closed loop of the crystal oscillation circuit 1. The compensation voltage generation circuit uses compensation data based on the frequency temperature characteristics of the crystal oscillation circuit 1
Generate a compensation voltage. In such a case, the oscillation circuit 4
Further, the IC chip 6 and the crystal unit 3 shown by a dotted frame in which the temperature compensation mechanism 2 is integrated are integrated with each other.

As a specific first example (two-room type), as shown in FIG. 5, for example, a quartz piece 8 is placed in one concave portion of a container body 7 made of a laminated ceramic having an H-shaped cross section. It is held, and the cover 9 is put thereon by, for example, seam welding and hermetically sealed. Then, a circuit element including at least the IC chip 6 is accommodated in the other concave portion, and a filler (not shown) is embedded. A mounting terminal 10 for surface mounting is provided on a side wall and an end surface of the other concave portion. Further, a writing terminal 11 for compensation data is provided on a side surface of the container body 7. Reference numeral 12 in the figure denotes a conductive adhesive for electrically and mechanically connecting and holding the crystal blank 8, and reference numeral 19 denotes a metal ring for seam welding.

[0005] As a second example (joining type), for example, an existing quartz oscillator 3, that is, a quartz body 8 in which a quartz piece 8 is hermetically sealed in a container body made of a laminated ceramic, is provided on the back surface of the quartz oscillator 3.
The mounting container 13 accommodating the C chip is joined (FIG. 6). However, the writing terminal 1 is provided on the side surface of the mounting container 13.
1 and a mounting terminal 10 on an end face and a side face. In the figure, reference numeral 14 denotes a mounting electrode of the crystal resonator 3, and reference numeral 15 denotes a bonding electrode of the mounting container 13.

As a third example (one room type), the IC chip 6 is fixed to the bottom of the concave portion of the container body 16 and the crystal blank 8 is fixed to the stepped portion of the concave portion and hermetically sealed (FIG. 7). However, the writing terminal 11 is provided on the side surface of the container body 16, and the mounting terminal 10 is provided on the side surface and the back surface.

[0007]

(Problems to be Solved by the Invention)
However, the temperature-compensated oscillator having the above-described configuration has the following problems, although it has each feature. That is, the first
In the example two-room type (FIG. 5), since the crystal chip 8 is hermetically sealed in the container body 7 and then the IC chip 6 is accommodated, there is a problem that the manufacturing process becomes a series and the productivity is reduced. Was. In addition, since the container body 7 is formed in an H shape by firing, the horizontal portion (central partition plate) formed in the H shape is bent, resulting in poor flatness. Therefore, when the IC chip 6 is fixed by, for example, ultrasonic thermocompression bonding using bumps, there has been a problem that electrical connection failure occurs.

In the second joining type (FIG. 6),
Since the mounting container 13 may be manufactured and joined in parallel with the crystal unit 3, the productivity is improved. However, since both the crystal unit 3 and the mounting container 13 have a bottom wall, there is a problem that the height dimension is increased accordingly.

Further, a one-room type of the third example (FIG. 7)
In this case, the height can be reduced most easily. However, since the crystal piece 8 is held after the IC chip 6 is fixed, the characteristic as the crystal unit 3 alone and strong excitation for removing minute foreign matter cannot be performed. there were. That is, there is a problem of lack of reliability.

(Object of the Invention) It is an object of the present invention to provide a temperature-compensated oscillator which is particularly suitable for reduction in height and has improved productivity and reliability.

[0011]

The present invention comprises a flat terminal plate 17 having a plurality of lead terminals 17 (af).
The IC chip 6 is arranged on the other surface side of the flat terminal plate 17, and each of the lead terminals 17 (a to f) is directly connected to a plurality of terminal electrodes of the IC chip 6. The crystal resonator 3 is arranged on the side and the lead terminals 17 a connected to the crystal terminal electrodes of the IC chip 6 are directly connected to the mounting electrodes 14 of the crystal resonator 3, and the IC chip 6 is resin-molded 18. The lead terminals 17 (be) connected to the power, output and ground terminal electrodes of the chip 6 are bent from the side to the bottom of the resin mold 18 as mounting terminals for surface mounting, and the temperature compensation mechanism of the IC chip 6 is provided. The solution is that the lead terminal 17f for writing the compensation data by connecting to the side of the crystal resonator 3 is bent (see FIGS. 1 to 3).

[0012]

According to the present invention, the IC chip and the mounting terminals of the flat terminal plate are connected separately from the manufacturing process of the crystal unit, and then integrated with the crystal unit. Therefore, compared to the two-room type (H structure), the manufacturing process is performed in parallel. In addition, the flatness of the flat terminal plate is made better than that of the two-room type partition plate. Further, compared with the joint type, the flat terminal plate is used, so that the bottom wall layer of the mounting container is not required. Furthermore, compared to the one-room type, a quartz oscillator with a sealed crystal piece is used, so it can be handled independently. Hereinafter, an embodiment of the present invention will be described.

[0013]

1 to 3 are views of a temperature-compensated oscillator for explaining an embodiment of the present invention. FIG. 1 is a schematic sectional view,
FIG. 2 is a bottom view, and FIG. 3 is a view of a flat terminal plate. The same parts as those in the prior art example are denoted by the same reference numerals, and description thereof will be simplified or omitted. The temperature-compensated oscillator includes a crystal oscillation circuit 1 including a crystal resonator 3 and an oscillation circuit 4, and a temperature compensation mechanism 2 for applying a compensation voltage to a voltage variable capacitance element 5 inserted in an oscillation closed loop. Then, the oscillation circuit 4 including the voltage variable capacitance element 5 excluding the crystal oscillator 3 and the temperature compensation mechanism 2 are integrated in the IC chip 6 (see FIG. 4).

In this embodiment, the temperature-compensated oscillator comprises the crystal unit 3, the IC chip 6, the flat terminal plate 17, and the resin mold 18. As described above, the crystal resonator 3 hermetically seals the crystal piece 8 in the container body and has a mounting electrode on the bottom surface. The flat terminal plate 17 includes a plurality of lead terminals 17.
(A to f) are arranged in a plane. One end of each lead terminal is concentrated in the central area. Here, a metal flat plate made of copper is pressed to form a plurality of lead terminals on the frame 20.
Connect to Reference numeral 21 denotes a connecting portion, and the width is omitted.

In such a case, first, the frame 20
The tip of the plurality of lead terminals 17 (a to f) concentrated in the central region of the flat terminal plate 17 having the above-mentioned shape and each terminal electrode (not shown) exposed on the surface of the IC chip 6 are superimposed by using a bump 22. Electrically and mechanically connected by sonic thermocompression bonding (FIG. 3). The dotted line in the figure is a bent portion. Next, the pair of mounting electrodes 14 of the crystal unit 3 and the lead terminals 17a connected to the pair of crystal terminal electrodes of the IC chip 6 electrically connected to the crystal unit 3 are connected to the bumps 22 as described above. Connection by ultrasonic thermocompression bonding.

Next, the I disposed on the bottom surface of the crystal unit 3
A resin is injected around the C chip 6 using a mold, and the resin is cured to form a resin mold 18. And power, output, ground and AFC (automatic frequency control) of IC chip 6
The lead terminal 17 (bcde) connected to the electrode terminal is bent to the lower surface of the resin mold to form a mounting terminal for surface mounting. Further, a plurality of lead terminals 1 connected to terminal electrodes for writing compensation data to the temperature compensation mechanism of the IC chip 6.
7f is bent toward the side surface of the crystal unit 3 to form a writing terminal.

With such a configuration, the IC chip and the mounting terminals of the flat terminal plate are connected separately from the crystal resonator manufacturing process, and then integrated with the crystal resonator. Therefore, as compared with the conventional two-room type (H structure) in which the crystal blank 8 and the IC chip 6 are separately housed, the manufacturing process is performed in parallel, so that the productivity is improved. Further, since the flat terminal plate 17 is used, the flatness is made better than that of the partition plate having the H structure. Therefore, in this example, electrical connection by the bumps 22 is ensured. In particular, in this example, an existing quartz resonator currently in circulation is used, so that it is economical.

Further, as compared with the bonding type in which the mounting container 13 is bonded to the bottom surface of the crystal unit 3, the mounting terminal 13 is not required because the flat terminal plate 17 is used. Further, the thickness of the flat terminal plate 17 can be made smaller (about 100 μm or less) than the bottom wall layer (about 700 μm) of the mounting container 13, thereby promoting a reduction in height as a whole.

Further, as compared with the one-room type in which the crystal blank 8 and the IC chip 6 are housed together, the crystal resonator 3 in which the crystal blank 8 is hermetically sealed is used. Therefore, the quartz oscillator can be handled independently, and the electrical characteristics of the quartz oscillator alone can be confirmed in advance. Then, the foreign matter can be removed by the strong excitation, and so-called DLD (Drive Level dependency) countermeasures can be taken. Therefore, reliability can be improved.

Further, since the lead terminal 17f serving as a writing terminal is bent toward the crystal oscillator side opposite to the mounting terminals 17 (b to e), the lead terminal 17f is electrically connected to the circuit pattern of the circuit board on which it is mounted. Connections can be reliably avoided.

[0021]

[Other Matters] In the present invention, the crystal resonator 3 having the mounting electrodes 14 formed at both ends is used. However, the present invention can be applied to a case where mounting electrodes are provided at four corners. What is necessary is just to change each lead terminal arbitrarily. Although the lead terminal 17f serving as a writing terminal is bent on the side surface of the crystal unit 3, for example, a notch can be provided on the side surface of the crystal unit 3 and embedded in the surface to maintain the planar outer dimensions. .

On the other main surface side of the flat terminal plate 17, I
Although only the C chip is disposed and molded with resin, for example, a bypass capacitor (not shown) between the power supply and the ground may be provided. In this case, a lead terminal for this may be added to the flat terminal plate 17. Although the number of lead terminals 17f for writing terminals is four, it can be increased or decreased as necessary. Further, for example, the lead terminal 17a connected to the crystal terminal electrode is extended to the crystal resonator 3 side, and the temperature compensated oscillator is provided. After assembling, the characteristics of the single crystal unit may be measured.

The terminal electrodes of the IC chip 6 and the lead terminals 17 (af) and the mounting electrodes 14 and the lead terminals 17
a was ultrasonic thermocompression bonding or thermocompression bonding using bumps,
If necessary, a connection using a conductive adhesive or the like may be used.

[0024]

According to the present invention, a flat terminal plate having a plurality of lead terminals is provided, and an IC chip is arranged on the other surface side of the flat terminal plate, and each lead terminal and a plurality of terminal electrodes of the IC chip are connected. The crystal chip is directly connected, the crystal resonator is arranged on one side of the flat terminal plate, and the lead terminal connected to the crystal terminal electrode of the IC chip is directly connected to the mounting electrode of the crystal resonator to connect the IC chip. The lead terminals connected to the power, output and ground terminal electrodes of the IC chip are bent from the side to the bottom of the resin mold as mounting terminals for surface mounting, and connected to the IC chip temperature compensation mechanism. Since the lead terminal for writing the compensation data is bent on the side surface of the crystal unit, it is possible to provide a temperature-compensated oscillator that is particularly suitable for reducing the height and has improved productivity and reliability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a temperature-compensated oscillator explaining one embodiment of the present invention.

FIG. 2 is a bottom view of the temperature-compensated oscillator explaining one embodiment of the present invention.

FIG. 3 is a plan view of a flat terminal plate for explaining one embodiment of the present invention.

FIG. 4 is a block circuit diagram of a temperature compensated oscillator explaining a conventional example.

FIG. 5 is a cross-sectional view of a temperature-compensated oscillator explaining a first example of a conventional example.

FIG. 6 is a cross-sectional view of a temperature-compensated oscillator illustrating a second example of the related art.

FIG. 7 is a cross-sectional view of a temperature-compensated oscillator explaining a third example of the related art.

[Explanation of symbols]

Reference Signs List 1 crystal oscillation circuit, 2 temperature compensation mechanism, 3 crystal oscillator, 4 oscillation circuit, 5 voltage variable capacitance element, 6 IC chip, 7, 16 container body, 8 crystal piece, 9 cover, 1
0 mounting terminal, 11 writing terminal, 12 conductive adhesive,
13 mounting container, 14 mounting electrode, 15 connection electrode, 1
7 flat terminal board, 17 (af) lead terminal, 18
Resin mold, 19 metal ring, 20 frame,
21 connecting part, 22 bump

Claims (1)

[Claims] A temperature for surface mounting, comprising: a quartz resonator having a pair of mounting electrodes on a bottom face in which a quartz piece is hermetically sealed, and an IC chip provided with an oscillation circuit and a temperature compensation mechanism excluding the quartz resonator. In the compensated crystal oscillator, a flat terminal plate having a plurality of lead terminals is provided, and the IC chip is disposed on the other side of the flat terminal plate, and each of the lead terminals and a plurality of terminal electrodes of the IC chip are connected Directly connected, the crystal unit is arranged on one surface side of the flat terminal plate, and the lead terminals connected to the crystal terminal electrodes of the IC chip are directly connected to the mounting electrodes of the crystal unit. Then, the IC chip is resin-molded, and the lead terminals connected to the power, output and ground terminal electrodes of the IC chip are used as mounting terminals for surface mounting, from the side to the bottom of the resin mold. Was bent, the temperature compensated crystal oscillator of the lead terminals for writing compensation data connected with the temperature compensating mechanism, characterized in that the bent sides of the crystal oscillator.