JPH08307153A - Structure of package - Google Patents

Abstract

PURPOSE: To rewrite temperature compensation data without a defect such as complicated manufacture process or malfunction due to mis-connection of terminals by providing a recessed part to a proper position in the middle of a lower side of a package and fixing a continuity terminal for internal memory rewrite to the inner bottom of the recessed part. CONSTITUTION: Conductor patterns arranged between each of ceramics layers 2 forming a package 1 are electrically connected by via-holes as required. Then inter-layer conductive patterns connected respectively electrically to an input output conductor terminal 16a arranged to an end ridge of the package 1 or an internal memory rewrite conducting terminal 16b arranged to an inner bottom side of a recessed part 15 provided in the middle of a lower side of the package 1 by via-holes. In the adjustment after the assembling, a jig is used to connect a jumper pin to the input output terminal 16a and the adjustment terminal 16b to secure electric connection and data are rewritten to a memory in an IC chip 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in the structure of a temperature-compensated crystal oscillator package having a conductive terminal capable of rewriting the memory contents of a semiconductor element inside from outside after assembly.

[0002]

2. Description of the Related Art A temperature-compensated crystal oscillator that suppresses fluctuations in oscillation frequency due to temperature changes and always obtains stable output is
It has a structure in which parts such as a crystal oscillator, a chip resistor, a chip capacitor, and a trimmer capacitor are mounted on an alumina substrate on which a conductive pattern is printed by using solder and are hermetically housed in a package made of an insulating material. . For the above trimmer capacitor, cover it with a metal cap having a hole immediately after mounting, and set the capacitance value of the trimmer capacitor so that the output frequency becomes constant over the desired temperature range after mounting each component. Is adjusted.

By the way, due to recent advances in semiconductor technology, there has been an oscillator in which compensation data to be temperature-compensated is stored in a semiconductor memory and the compensation data corresponding to a change in temperature is read to perform temperature compensation. is there. In such a temperature-compensated crystal oscillator, for example, the oscillator is housed in a thermostatic chamber, the ambient temperature is changed, and compensation data at each temperature is stored in a semiconductor memory. When the operation of storing the unique temperature compensation data is performed, it is necessary to send data corresponding to each temperature from the outside and write the data in the semiconductor memory.

As a recent temperature compensation type crystal oscillator, IC
There has been proposed a configuration in which a crystal resonator and an oscillation circuit are housed in an LCC (leadless chip carrier) type package which is widely used as a package for a laser. For example, in Japanese Unexamined Patent Publication No. 6-232630, an insulating substrate on which a crystal oscillation circuit is mounted extends as a connection substrate outside the package beyond a break line formed of perforations and through holes. By making the edge part of the edge connector shape, the IC on the substrate is
Write temperature compensation data to the semiconductor memory that is a chip,
After that, the connection substrate is cut off by a break line. After the connection board is cut off, the temperature compensation data can be written using the through-hole conductor (pad) remaining on the cut surface. However, in this conventional technique, it is necessary to cut off the connection substrate after data writing at the time of manufacturing, resulting in an increase in processes and waste of substrate resources.

Further, Japanese Utility Model Laid-Open No. 6-34260 discloses that
A package having a rectangular parallelepiped shape has normal I / O terminals arranged on a pair of opposite side surfaces, and an inverted L-shaped cutout is provided on the other pair of side surfaces so that adjustment terminals do not protrude from the side surfaces. Is disclosed below. However, in this conventional example, since the terminals for adjustment are provided by utilizing the side surface of the package, the number of terminals for rewriting the internal memory is limited by the size of the package, and the location of the input / output terminals is Since the number of terminals is limited, the degree of freedom in design is narrowed down.In addition, when inserting the contact pin placed in the jig into the above notch and making contact with the terminal inside the notch, stabilize the pin tip. It is difficult to keep the terminal in contact with the terminal, the pin disengages from the terminal and escapes to the outside of the package, the connection with the terminal is not performed well, and good adjustment cannot be expected.

Further, Japanese Utility Model Laid-Open No. 6-13155 discloses that
A configuration is disclosed in which normal input / output terminals are arranged on a pair of opposing side surfaces of a rectangular parallelepiped package, and adjustment terminals are arranged on another pair of side surfaces. However, in this conventional example, since the terminal for rewriting the internal memory is provided in the flat portion on the side surface of the package, the user may mistake this terminal for other terminals and make an erroneous operation. If masking or the like is applied to the end support after rewriting in order to eliminate a defect, an extra step is added and the device cost is increased.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and in a temperature-compensated crystal oscillator having a structure in which a substrate on which a crystal oscillator, a memory IC chip, etc. are mounted is hermetically sealed by a package, a terminal is mistakenly detected. It is an object of the present invention to provide a temperature-compensated crystal oscillator that can rewrite temperature-compensated data without causing a malfunction such as a malfunction or complicating a manufacturing process.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a recess in a central portion of a lower surface of a main body of a package for accommodating a crystal oscillator and an IC therein, and rewriting an internal memory in an inner bottom portion of the recess. The conductive terminal of is fixed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings. 1 (a) and 1 (b) are a longitudinal sectional view and a bottom view of a temperature-compensated crystal oscillator according to an embodiment of the present invention, and FIG. 2 is a plan view of the same crystal oscillator with a cap removed. Shows. Reference numeral 1 is the body of the package, and the package 1 generally has a structure in which green sheet-shaped oxidatively fired ceramics 2 are multilayered and conductive patterns are arranged on the surface and between the layers. The central portion of the package 1 has a concave shape, and the outer circumference of the concave portion is an annular surrounding portion 3. On the upper surface of the annular surrounding portion 3, a gold-plated preform 4 of an annular kovar is fixed by brazing. 5 is a cap,
A thin Kovar plate with gold plating is used. This cap 5 is preformed by parallel seam welding.
Stuck on top. As a result, the cap 5 is the package 1
It is fixed to the annular surrounding portion 3 to hermetically seal the inside of the package. Reference numeral 6 is an IC chip fixed to the inner bottom surface of the recess of the package via a conductive adhesive 6a, and 7 is a bonding wire made of Au, Al, or the like, on an overhanging portion 8 provided at a proper position of the recess. The pad 9 provided on the terminal and the terminal of the IC chip 6 are connected. Reference numeral 10 is a crystal resonator element, and a crystal resonator element having a good frequency-temperature characteristic generally called AT cut is used as the element 10. The crystal unit 10 is cantilevered and electrically and mechanically fixed to the crystal unit connecting terminal 11 provided in the recess of the package 1 by a conductive adhesive 10a.

The conductive patterns arranged between the ceramic layers 2 constituting the package body 1 are electrically connected by via holes, if necessary. These interlayer conductive patterns are used for input / output conductive terminals 16a arranged on the edge of the main body 1 or for rewriting the internal memory arranged on the inner bottom surface of the recess 15 provided at the center of the lower surface of the package main body 1. The via holes are electrically connected to the conductive terminals 16b, respectively. Note that reference numeral 16c
Is a dummy terminal provided for thermal stress relaxation.

Conductive terminal 1b for rewriting the internal memory
Is fixed to the inner bottom surface of a plurality of recesses 15 arranged in the central portion of the bottom surface of the package body 1, that is, in the central portion excluding the end edges of the body where the other terminals 16a and 16c are provided. And is connected to the terminals and the like of the IC chip 6 through the via holes, pads 9, wires 7 and the like (not shown).

In the above embodiment, the bonding between the pad (conductive pattern) on the package side and the IC chip is realized by a bonding wire, but this is an example, and a connecting means other than the bonding wire, for example, a flip chip is used. It is also possible to use chips, bumps, solders, conductive adhesives and the like.

The temperature-compensated crystal oscillator having the above structure is soldered and fixed on a circuit board (not shown) through its input / output terminals 16a, as in the case of a normal surface mount device. Further, in the adjustment after the assembly, a jig is used to connect the conducting pin to the input / output terminal 16a, and then a similar pin-shaped terminal is also connected to the adjusting terminal 16b to make electrical connection. After securing the data, the data in the memory in the IC chip is rewritten. Needless to say, it is not necessary to connect the pin to the input / output terminal 1a when rewriting the data.

In manufacturing the temperature-compensated crystal oscillator having the above-mentioned structure, it is not necessary to make use of a manufacturing technique which is particularly difficult as compared with the conventional IC package, and addition or modification of the manufacturing process is required. However, since only the mold for producing the package 1 needs to be slightly changed, there is no possibility of increasing the manufacturing cost.

A recess 1 is formed in the center of the lower surface of the package 1.
5 and the conductive terminal 16b for rewriting the internal memory is provided on the inner bottom surface of the recess, the position and number of the input / output terminals arranged on the side of the package body can be maintained as usual. , There is no restriction due to the existence of the terminal for rewriting the internal memory. Therefore, it is possible to provide as many internal memory rewriting terminals as necessary, and since the recesses 15 serve as guides for reliably guiding the pins of the jig to the terminals 16b, the pins are surely connected to the terminals 16b. Therefore, workability at the time of rewriting can be improved. Furthermore, since the rewriting conductive terminal 16b is located on the inner bottom surface of the recess 15 away from the edge of the package, the user cannot operate the conductive terminal 16b by mistake. Further, since the terminal 16a which may be needed by the user is arranged in an exposed state on the edge of the package body, no inconvenience occurs for the user.

The recess 15 may be a circular hole having a small diameter for one pin, or a plurality of conductive terminals may be arranged on the inner bottom surface of one large diameter recess 15. Moreover, the recess 15 may be a polygon other than a circle. Further, the diameter of the recess 15 does not have to be the same over the entire length in the depth direction, and may be tapered so that it becomes narrower (or wider) toward the inside.

Although the temperature-compensated crystal oscillator has been described in the above embodiments, the present invention relates to another crystal oscillator package, an oscillator package using a piezoelectric component other than crystal, or an oscillator not using a piezoelectric component. It is also applicable to packages. Further, it is applicable to general IC packages that require adjustment of their characteristics after assembly.

[0018]

As described above, the present invention is a crystal unit and an IC.
Since a recess is provided at a proper place in the center of the lower surface of the main body of the package that accommodates and, and the conductive terminal for rewriting the internal memory is fixed to the inner bottom of the recess, it is the same as the conventional LCC package without increasing the number of steps. Can be manufactured by the manufacturing process described above and there is no restriction on the design due to the conductive terminal for rewriting the internal memory. Further, since the conductive terminal for rewriting the internal memory is arranged on the inner bottom surface of the recess provided on the bottom surface of the package body, which has never been considered as a dead space, it is possible to arrange a required number of the terminals. Since the recess serves as a guide for the jig, rewriting work of the internal memory by the jig becomes easy and accurate.

[Brief description of drawings]

1A and 1B are a vertical cross-sectional view and a bottom view of a temperature-compensated crystal oscillator according to an embodiment of the present invention.

FIG. 2 is a plan view of the crystal oscillator of FIG. 1, showing a state in which a cap is removed.

[Explanation of symbols]

1 package body, 2 green sheet-shaped oxidatively fired ceramics, 3 annular surrounding part, 4 preform, 5
Cap, 6 IC chips, 7 bonding wires,
8 overhang part, 9 pad, 10 crystal unit, 1
0a adhesive, 11 crystal resonator connecting terminal, 15 recess, 16a input / output terminal, 16b conductive terminal, 16c
Dummy terminal.

Claims (2)

[Claims] 1. A package in which a semiconductor element is housed, wherein at least one recess is provided at an appropriate position in the center of the bottom surface of the package, and a conductive terminal is arranged on the inner bottom of the recess. The structure of the package to be used. 2. The structure of a package according to claim 1, wherein a temperature compensation type piezoelectric oscillator is housed in the package, and temperature compensation information is inputted from the outside through the conduction terminal.