KR20090094981A - Package of crystal oscillator - Google Patents

Abstract

A crystal oscillator package is provided to effectively determine a gap between a crystal blank and a floor layer by preventing a contact of a floor layer and an electrode pattern formed on a surface of the crystal blank. A first electrode pad(24a) and a second electrode pad(24b) are formed on a top surface of a floor layer(26a). A crystal blank(21) is vibrated by an electric signal. A first electrode pattern(22a) and a second electrode pattern(22b) are formed on top and bottom surfaces, and are connected to the first electrode pad and the second electrode pad. A bump(25) is formed on a top surface of the floor layer, and is arranged between the first electrode pad or the second electrode pad and the first electrode pattern or the second electrode pattern. A supporting layer(26b) is formed on a top part of the floor layer, and forms a space part which receives the crystal blank. A lid(27) is arranged on the supporting layer, and seals the space part. The floor layer is made of insulation ceramic material.

Description

Crystal Oscillator Package {PACKAGE OF CRYSTAL OSCILLATOR}

The present invention relates to a crystal oscillator package, and more particularly, to a crystal oscillator package capable of eliminating instability of the piezoelectric effect caused by contact of a bottom layer with an electrode pattern formed on a crystal piece due to warpage of the crystal oscillator package. .

In general, crystal oscillators are used for various purposes, such as frequency oscillator, frequency regulator, frequency converter. The crystal oscillator uses a crystal having excellent piezoelectric properties as a piezoelectric material, which acts as a stable mechanical vibration generator.

The crystals are artificially grown in a high pressure autoclave, cut around a crystal axis, and processed in size and shape to have desired characteristics, thereby producing a wafer. The correction should be made to have low phase noise, high Q value, and low frequency change with time and environmental changes. Here, the Q value is a value representing band selection characteristics in a resonator, a filter, an oscillator, etc., and is also referred to as a quality factor. And, the Q value is calculated as the ratio of the center frequency to the three-day (dB) bandwidth, the larger the Q value is the oscillator with better frequency selection characteristics.

In order for the quartz wafer to be used as a quartz crystal vibrator, a quartz crystal cut piece must be fixed inside the package, and an electrode must be formed on the surface of the quartz crystal for electrical connection. In addition, the crystal piece fixed inside the package is bonded to the package with a conductive adhesive to connect with external electrical elements. At this time, sufficient adhesion area should be secured to ensure excellent vibration efficiency of the crystal piece and reliability against external impacts.

On the other hand, the crystal oscillator is greatly affected by the operation efficiency and quality due to external environmental changes and contamination, so that the package leakage rate (leak rate) is very low to protect the crystal from the environment and contaminants outside the package It should be sealed as much as possible. At this time, in the method of sealing the package, after adhering the support layer on the bottom layer, the lid is sealed on the support layer and the support layer. At this time, the airtightness at the adhesive part between the bottom layer and the support layer, the support layer and the lead becomes very important, and when a pollutant from the outside flows, various problems such as reliability deteriorate.

In addition, the crystal oscillator is small and can obtain stable frequency even when the external environment changes, so it is used in the character composition and color composition circuit in computer, communication equipment, etc. In addition, the voltage controlled crystal oscillator (VCXO), temperature compensation type crystal It is widely used in products such as oscillator (TCXO) and constant temperature controlled crystal oscillator (OCXO).

1 and 2 are side cross-sectional and top views of a conventional crystal oscillator package of the related art. 1 and 2, the conventional crystal oscillator package includes a bottom layer 16a, first and second electrode pads 14a and 14b formed on the bottom layer 16a, and the first and second crystal packages. A crystal piece 11 having one side fixed on the second electrode pads 14a and 14b and a bump 15 disposed between an upper surface of the bottom layer 16a and the other side of the crystal piece 11. Has a structure. First and second electrode patterns 12a and 12b electrically connected to the first and second electrode pads 14a and 14b may be formed on upper and lower surfaces of the crystal piece 11, and the bottom layer 16a may be formed. The support layer 16b may be formed on the periphery of the support portion 16b to form a space for accommodating the crystal piece 11, and a lead 17 may be disposed on the support layer 16b to seal the space.

In the conventional crystal oscillator package as described above, the bottom layer 16a made of a ceramic material may be warped under the influence of an external environment such as ambient temperature and humidity, and the crystal piece 11 may be caused by the warp phenomenon. The electrode pattern 12b formed on the lower surface of the bottom layer 16a may be in contact with each other. As such, the contact between the electrode pattern 12b formed on the lower surface of the crystal piece 11 and the bottom layer 16a affects the piezoelectric performance of the crystal piece. Thus, when designing the crystal oscillator package, a desired electrical effect may be obtained from the package. Problems may not arise.

The present invention provides a crystal oscillator package capable of obtaining a desired piezoelectric effect by preventing contact between an electrode pattern formed on a surface of a crystal piece and a bottom layer even when a bending phenomenon occurs in the bottom layer of the crystal oscillator package.

The present invention to achieve the above technical problem,

Bottom layer;

First and second electrode pads formed on an upper surface of the bottom layer;

A crystal piece having one side fixedly installed on the first and second electrode pads, and having first and second electrode patterns electrically connected to the first and second electrode pads respectively formed on upper and lower surfaces thereof to vibrate by an electrical signal;

A bump formed on an upper surface of the bottom layer and disposed between the first or second electrode pad and the first or second electrode pattern;

A support layer formed on a periphery of the bottom layer and forming a space for accommodating the crystal piece; And

A lid disposed on the support layer to seal the space part

It provides a crystal oscillator package including a.

Preferably, the bottom layer may be formed of an insulating ceramic material, and the support layer may be formed of an insulating ceramic material or a conductive metal alloy material. In addition, the bump is preferably formed of an insulating material.

In one embodiment of the present invention, the height and position of the bumps, the height from the bottom layer of the other side facing the one side of the crystal piece than the height from the bottom layer of one side of the crystal piece fixed to the first and second electrode pads. Is preferably set to be higher. In addition, it is more preferable that the height and position of the bump are set so that the other side of the crystal piece does not contact the lead.

According to the present invention, even if a bending phenomenon occurs in the bottom layer of the crystal oscillator package, there is an effect that can effectively determine the distance between the crystal piece and the bottom layer so that the bottom layer and the crystal piece, which is a piezoelectric element, do not contact each other.

Through this, it is possible to secure a stable output of the crystal oscillator package.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiment of this invention is provided in order to demonstrate this invention more completely to the person skilled in the art to which this invention belongs. Therefore, it should be noted that the shape and size of the components shown in the drawings may be exaggerated for more clear explanation.

3 and 4 are a cross-sectional side view and a plan view of a crystal oscillator package according to an embodiment of the present invention.

3 and 4, the crystal oscillator package according to an embodiment of the present invention includes a bottom layer 26a and first and second electrode pads 24a and 24b formed on an upper surface of the bottom layer 26a. First and second electrode patterns 22a and 22b are fixedly installed on one side of the first and second electrode pads 24a and 24b and electrically connected to the first and second electrode pads 24a and 24b. ) Is formed on the upper and lower surfaces, respectively, and is formed on the crystal piece 21 vibrating by an electrical signal, and is formed on the upper surface of the bottom layer 26a. The first or second electrode pads 24a and 24b and the first or Bump 25 disposed between second electrode patterns 22a and 22b, support layer 26b and support layer formed on the periphery of bottom layer 26a and forming a space portion for accommodating the crystal piece 21. It may be configured to include a lid 27 disposed on the 26b to seal the space.

The bottom layer 26a is a base member of the crystal oscillator package and may be formed of an insulating ceramic material. First and second electrode pads 24a and 24b may be formed on one side of the top surface of the bottom layer 26a, and bumps 25 may be disposed on the top surface of the bottom layer 26a. In addition, a support layer 26b may be formed at the periphery of the bottom layer 26a.

Although not shown in FIGS. 3 and 4, a bottom surface of the bottom layer 26a may be provided with a plurality of external electrode pads for receiving an electrical signal from the outside, and one of the plurality of external electrode pads may be the first electrode. The pad 24a may be electrically connected, and another one of the plurality of external electrode pads may be electrically connected to the second electrode pad 24b. Electrical connection between the first and second electrode pads 24a and 24b and the external electrode pad may be made by a conductive via hole formed in the bottom layer 26a. In addition, some of the plurality of external electrode pads may be used as ground electrodes to be grounded.

The first and second electrode pads 24a and 24b are electrically connected to the electrode patterns 22a and 22b formed on the upper and lower surfaces of the crystal piece 21 to provide an electrical signal to the crystal piece 21. It may be a means for generating a piezoelectric effect on the crystal piece 21, and outputs an electrical signal according to the piezoelectric effect of the crystal piece 21. The first and second electrode pads 24a and 24b may be formed of a conductive metal material, and include, for example, gold (Au), silver (Ag), tungsten (W), copper (Cu), and molybdenum (Mo). It may be formed using at least one metal material selected from the group.

As described above, the crystal piece 21 may be manufactured by cutting the crystal wafer, and electrode patterns 22a and 22b may be formed on upper and lower surfaces of the crystal piece 21 for electrical connection. . One side of the crystal piece 21 may be fixed in the crystal oscillator package. Specifically, the crystal piece 21, the first and second electrode pads (24a, 24b) formed on the bottom layer (26a) and the upper and lower sides of the crystal piece 21 for electrical connection with external electrical elements. The electrode patterns formed on the surface may be fixed by the conductive adhesive 23 to be in contact with each other. Electrode patterns formed on upper and lower surfaces of the crystal piece 21 may be formed by deposition of a metal material such as gold (Au), silver (Ag), or the like.

The bump 25 may be formed on an upper surface of the bottom layer 26a and applied as a support member for supporting the crystal piece 21. In particular, the bump 25 may be disposed very close to the junction where the crystal piece 21 and the first and second electrode pads 24a and 24b are bonded to each other. More specifically, the bumps 25 may be disposed between the first or second electrode pads 24a and 24b and the first or second electrode patterns 22a and 22b.

In particular, the bump 25 is one side of the crystal piece 21 than the height from the bottom layer 26a of one side of the crystal piece 21 fixed to the first and second electrode pads 24a and 24b. The position disposed with the height can be set so that the height from the bottom layer 26a on the other side opposite to is higher. That is, as shown in FIG. 3, in one embodiment of the present invention, the bumps 25 are disposed between the electrode pads 24a and 24b and the electrode pattern 22b to have the bottom layer 26a of the crystal piece 21. To keep the height from the top high.

Since the bump 25 has a very narrow contact surface with the bottom layer 26a due to its structural characteristics, there is a limit in increasing its height. Therefore, when the bump is installed on the opposite side of the side on which the crystal piece is fixed, as in the conventional crystal oscillator package, the gap between the crystal piece and the bottom layer cannot be made large enough. As a result, bending occurs, the electrode pattern of the crystal piece The problem arises that the bottom layers come into contact with each other.

In contrast, according to one embodiment of the present invention, the bump 25 is disposed adjacent to the junction where the crystal piece 21 and the first and second electrode pads 24a and 24b are joined to each other. Even when bumps having the same height as the used bumps are used, the gap between the crystal piece 21 and the bottom layer 26a can be kept sufficiently large. In addition, it is preferable that the bump 25 has a height and an arrangement position set so that the other side opposite to the one side on which the crystal piece 21 is fixed does not contact the lid 27. The bumps 25 are preferably made of various materials, for example insulating materials such as insulating ceramics.

The support layer 26b may be formed on the periphery of the bottom layer 26a and may form a space for accommodating the crystal piece 11. The support layer 26b may be made of an insulating ceramic material of the same material as the bottom layer 26a, or may be formed of a conductive metal alloy material of the same material as the lead 27. In addition, the lid 27 may be disposed to be covered on the support layer 26b to seal the space in which the crystal piece 21 is mounted, and may be fixed through a sealing process. As described above, the crystal oscillator is greatly affected by the operational efficiency and quality due to external environmental changes and contamination, so that the package leak rate is increased to protect the crystal from the environment and contaminants outside the package. It must be sealed to be very low.

In the foregoing detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

1 is a side view of a conventional crystal oscillator package.

2 is a plan view of a conventional crystal oscillator package.

3 is a side view of a crystal oscillator package according to an embodiment of the present invention.

4 is a plan view of a crystal oscillator package according to an embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

21: Crystal piece 22a, 22b: First and second electrode patterns

23: conductive adhesive 24a, 24b: first, second electrode pads

25 bump 26a bottom layer

26b: support layer 27: lead

Claims (6)

Bottom layer; First and second electrode pads formed on an upper surface of the bottom layer; A crystal piece having one side fixedly installed on the first and second electrode pads, and having first and second electrode patterns electrically connected to the first and second electrode pads respectively formed on upper and lower surfaces thereof to vibrate by an electrical signal; A bump formed on an upper surface of the bottom layer and disposed between the first or second electrode pad and the first or second electrode pattern; A support layer formed on a periphery of the bottom layer and forming a space for accommodating the crystal piece; And A lid disposed on the support layer to seal the space part Crystal oscillator package comprising a. The method of claim 1, The bottom layer is a crystal oscillator package, characterized in that formed of an insulating ceramic material. The method of claim 1, The support layer is a crystal oscillator package, characterized in that formed of an insulating ceramic material or a conductive metal alloy material. The method of claim 1, The bump is a crystal oscillator package, characterized in that formed of an insulating material. The method of claim 1, The height and position of the bump is set so that the height from the bottom layer on the other side facing the one side of the crystal piece is higher than the height from the bottom layer on one side of the crystal piece fixed to the first and second electrode pads. Crystal oscillator package. The method of claim 5, The height and position of the bump, the crystal oscillator package, characterized in that the other side of the crystal piece is set so as not to contact the lead.

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