JPS5929369Y2 - oscillation device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to improvements in oscillator devices such as electronic watches and electronic desktop calculators, and in particular, an LRI semiconductor chip and a crystal resonator on a lead frame are integrally molded with resin.

In recent years, crystal oscillators have been increasingly used in electronic watches, electronic clocks, and the like.

In these application examples, an oscillation circuit is constructed by combining an inverter and a crystal resonator in an LSI semiconductor chip.

Specifically, as shown in FIG. 1, an inverter 2 and a bias resistor 3 are built into an LSI semiconductor chip 1.

A capacitor 4 for oscillation frequency correction and a trimmer capacitor 5 are externally connected to the input/output terminals of the inverter 2.
Further, a crystal resonator 6 is externally attached between the input and output terminals of the inverter 2.

Now, in order to use such a crystal oscillator circuit as a highly accurate time standard, after connecting the LSI semiconductor chip 1 and the crystal oscillator 6, the oscillation frequency of the crystal oscillator 6 must be delicately controlled to achieve extremely accurate oscillation. I need to get the frequency.

For this reason, a method is generally used in which the capacitance of the external trimmer capacitor 5 is changed to control the oscillation frequency.

However, when adjusting the oscillation frequency of the crystal resonator 6, the frequency is usually finely adjusted even when the crystal resonator 6 is manufactured, so when the LSI semiconductor chip 1 and the crystal resonator 6 are combined, the frequency is further Adjustment was a double effort, and the process of frequency adjustment was complicated.

In addition, in assembling such an oscillation device, the LSI semiconductor deep 1, the capacitor 4, and the trimmer capacitor 5 are
, many electronic components such as the crystal resonator 6 are soldered to a printed wiring board or the like, making it difficult to miniaturize the oscillation device.

The present invention has been devised in view of the above points, and provides an oscillation device that eliminates the need for capacitors and trimmer capacitors, allows easy frequency adjustment, can be miniaturized, is inexpensive, and has excellent reliability.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic plan view of an oscillation device used in an electronic timepiece.

In the figure, reference numeral 10 denotes an LSI semiconductor chip having a clock circuit, etc., which is die-bonded and wire-bonded onto a lead frame 11 having a plurality of terminals extending therefrom, and then the entire chip is molded with an opaque resin 12.

This LSI semiconductor chip 10 has built-in inverter and bias resistor circuits (not shown) in the same manner as in the conventional example.

Reference numeral 13 denotes a crystal resonator which has a transparent window for laser trimming and whose frequency is not finely adjusted. It is attached onto the lead frame 11 terminals of the book by solder or conductive paste.

This crystal resonator 13 is a known one, and as shown in FIG.
Mount the ceramic package 14 and cover the top with the glass lid 1.
It has a sealed structure.

Further, on the bottom of the ceramic package 14, two terminals for external lead-out electrodes (not shown) are printed, and these electrodes are connected to the two terminals of the lead frame 11 described above.

Reference numeral 17 is a transparent resin (indicated by the dotted line), and the entire structure including the LSI semiconductor chip 10 attached to the lead frame 11 and the crystal resonator 13 is integrally molded.

This molding is performed by transfer molding, potting, or the like.

The oscillation device made with the above configuration is aged, and while the frequency of the crystal resonator 13 is stabilized, the transparent resin 13 is
7 and the glass lid 16 of the crystal oscillator 13, the load mass of the crystal oscillator piece 15 is laser trimmed, and the oscillation frequency is accurately final adjusted.

In this way, the LSI semiconductor chip 10 and the crystal resonator 13 are electrically connected using the lead frame 11, and the LSI semiconductor chip 10 and the crystal resonator 13 are electrically connected.
In the case where the entire SI semiconductor chip 10 is molded with opaque resin 12 and the whole including it is further integrally molded with transparent resin 17, the final adjustment of the oscillation frequency only needs to be made once after the oscillation device is completed. , the oscillation frequency adjustment process is very simple.

Further, since the oscillation frequency can be sufficiently adjusted by laser trimming, there is no need to provide a capacitor for correcting the oscillation frequency as in the conventional example, and the oscillation device can be made smaller.

In particular, the use of the transparent resin 1T increases resistance to external shocks and increases durability against moisture and the like, thereby improving the reliability of the oscillation device.

Furthermore, the lead frame 11 is useful because it is obtained at a lower cost in terms of material than a printed wiring board or the like.

It should be noted that by simply connecting a power source (battery) to the oscillation device of this embodiment, the output necessary for the electronic timepiece can be immediately obtained.

As described above, according to the present invention, a semiconductor chip and a crystal resonator are electrically connected to a lead frame, the semiconductor chip is molded with an opaque resin, and the semiconductor chip includes a portion molded with the opaque resin and the crystal resonator. Since the entire device is molded with transparent resin, the semiconductor chip circuit will not malfunction due to light incidence.

Furthermore, after the transparent resin is molded, laser trimming for the load mass of the crystal resonator piece can be performed by irradiating a laser from the outside through the transparent resin and the transparent body on the top of the crystal resonator package.
This has the outstanding advantage that the oscillation frequency can be adjusted with the semiconductor chip and the crystal resonator being very firmly fixed by a mold, and the oscillation frequency can be adjusted with extremely high precision.

In addition, since the entire device can be laser trimmed after molding, the oscillation frequency only needs to be adjusted once after the oscillation device is completed.Therefore, there is no need to provide a capacitor for oscillation frequency correction, and the oscillation device can be made smaller. It is possible to aim for

[Brief explanation of the drawing]

Fig. 1 is an electrical circuit diagram of a main part showing a conventional example, Fig. 2 is a schematic plan view showing an embodiment of the present invention, and Fig. 3 is a schematic sectional view showing a crystal resonator used in this embodiment. . 10... LSI semiconductor chip, 11...
・Lead frame, 12... Opaque resin, 13
......Crystal oscillator, 16...Translucent window,
17...Transparent resin.

Claims (1)

[Scope of utility model registration request] A semiconductor chip including an inverter circuit and a bias resistor circuit is electrically connected to a crystal resonator lead frame in which a crystal resonator piece is mounted in a package whose upper part is a transparent body (glass lid), and the semiconductor chip is molded with an opaque resin, the whole including the part molded with the opaque resin and the crystal resonator is molded with a transparent resin, and after the molding with the transparent resin, the crystal oscillator is molded with the transparent resin and the transparent body. An oscillation device characterized in that the oscillation device is equipped with a interceptor that enables laser trimming of the load mass of the crystal resonator piece by irradiating a laser from the outside.