KR20210122637A - Microstrip isolator having heatsink and its manufacturing method - Google Patents

Abstract

The present invention relates to formation of a heat sink in addition to a path in which heat generated from a load resistor of a terminated port when driving a microstrip type isolator device is driven is emitted from a ground metal layer (rear metal layer) formed on a lower surface of a substrate of a device. According to the present invention, provided is a microstrip type isolator including a heat sink, which comprises: a circulator metal layer formed on a first surface of a ferrite substrate; a front ground pad connected to one of ports of the circulator metal layer through a load resistor; a via hole formed in the front ground pad; and a rear metal layer formed on a second surface of the ferrite substrate. The rear metal layer is connected to the front ground pad and a heat sink metal layer through the via hole of the front ground pad and a via hole of the heat sink metal layer.

Description

{Microstrip isolator having heatsink and its manufacturing method}

The present invention relates to a method for manufacturing a microstrip type isolator operating at various frequencies, such as S-band and X-band radar, and a structure thereof.

In general, an isolator, a core component of S-band and X-band radars used in aircraft and ships, transmits signals to the antenna by minimizing signal loss in the direction of the output terminal. It is an irreversible element that blocks it from being transmitted.

One type of isolator, a microstrip isolator, is used to achieve high performance and miniaturization at high frequencies such as X-band. In particular, in a wireless communication system, the microstrip type isolator blocks the reverse signal or transmitted signal reflected wave flowing from the antenna to the power amplifier of the transmitter. It is applied in order to prevent and stabilize the performance of the transmitter.

A broadband antenna and an isolator according to the prior art will be described with reference to FIGS. 1 to 3 . 1 is a schematic diagram of a conventional broadband antenna, FIG. 2 is a plan view of a conventional isolator, and FIG. 3 is a cross-sectional view of a conventional isolator (cut AA′ in FIG. 2).

In FIG. 1, the isolator is manufactured in a structure in which one port P3 of a microstrip type circulator manufactured on a ferrite substrate is terminated through a thin film type load resistor. The port P3 is connected to the metal layer (ground) on the back side of the substrate through the via hole of the substrate. In FIG. 1 , port P1 of the circulator is connected to transmitter TX and port P2 is connected to antenna ANT, so that RF energy from TX is transferred to ANT, and returned energy from ANT is bypassed through port P3 make it

Such a microstrip type isolator is generally manufactured on a ferrite substrate, and its plan view is as shown in FIG. 2 . A circulator metal layer 10 is formed on the ferrite substrate 5 . Port 1 and Port 2 are formed to be connected to the circulator metal layer 10 . Port 3 is connected to the ground pad 14 on the front side. This front ground pad 14 is a partial region of the ground metal layer (front metal layer) on the front side. The front ground pad 14 is connected through a load resistor connected to the circulator metal layer 10 , that is, a thin film resistor 12 . Two or more load resistors may be formed and connected in parallel to the front front ground pad 14 . A via-hole 20 is formed in the front ground pad 14 . The via hole 20 is for connecting the front surface and the rear surface of the substrate 5 (ie, connecting the front ground pad 14 and the rear metal layer 24 in FIG. 3 ).

As the circulator metal layer 10 , a metal layer such as Ti/Au or Cu is applied and has a thickness of several to tens (eg, 1 to 20) μm. In addition, the thin film resistor 12 is generally deposited with a NiCr or TaN thin film layer using equipment such as a thermal evaporator, an E-beam evaporator, or a sputter. The front ground pad 14 may be formed of the same material as the circulator metal layer 10 .

Referring to the cross-sectional view taken along line A-A' in FIG. 3 , the inner diameter metal layer 22 is formed on the inner diameter sidewall of the via hole 20 . The front ground pad 14 of the substrate 5 and the rear metal layer 24 are electrically connected through the inner diameter metal layer 22 . Here, the back metal layer 24 is a ground metal layer. The back metal layer 24 may be formed of the same material as the circulator metal layer 10 .

In this prior art, a via hole 20 for connecting the front ground pad 14 on the front surface of the ferrite substrate 5 and the metal layer 24 on the rear surface must be formed in the ferrite substrate, and the front surface through the formed via hole 20 . The inner diameter metal layer 22 must be formed using a metal deposition process so that the ground pad 14 and the back metal layer 24 are connected.

When the microstrip type isolator device according to the prior art described above is driven, the power delivered to the terminated port is dissipated as heat in the thin film resistor 12. Accordingly, the thin film resistor 12 and the ferrite substrate ( 5), the temperature of the device may rise, causing abnormal device operation and destruction. Therefore, in general, the temperature of the ferrite substrate 5 is maintained below the Curie temperature, and the temperature of the ground metal surface of the lower surface of the substrate, that is, the rear metal layer 24, is constantly maintained at a specific temperature for smooth heat conduction. to drive the device in consideration of the heat dissipation effect.

The present invention further promotes the dissipation of heat generated from the thin film-type load resistance of the terminated port when driving the conventional microstrip type isolator device through the ground pad formed on the lower surface of the device substrate, and the load when driving the device It is intended to suppress excessive temperature rise of resistors and ferrite substrates, and to prevent abnormal driving and failure of devices.

In order to solve the above problem, a heat sink is additionally formed in addition to the path in which heat generated from the load resistance of the terminated port is radiated from the ground pad formed on the lower surface of the substrate when the microstrip type isolator device is driven.

According to one aspect of the present invention, a circulator metal layer formed on the first surface of a ferrite substrate, a front ground pad connected to one of the ports of the circulator metal layer through a load resistor, and a via hole formed therein, adjacent to the load resistor There is provided a microstrip type isolator including a heat sink, comprising a heat sink metal layer formed by the above method, a via hole formed therein, and a back metal layer formed on a second surface of the ferrite substrate. Here, the back metal layer is connected to the front ground pad and the heat sink metal layer through a via hole of the front ground pad and a via hole of the heat sink metal layer.

According to another feature of the present invention, in order to form the via hole of the front ground pad and the via hole of the heat sink metal layer, respectively, in the region where the front ground pad and the heat sink metal layer are to be formed on the first surface of the ferrite substrate, the region is formed in a via hole shape. to remove; forming a load resistor for terminating one of the ports of the circulator on the first surface of the ferrite substrate; forming a circulator metal layer, a front ground pad, and a heat sink metal layer in a circulator area, a front ground pad area, and a heat sink area of the first surface of the ferrite substrate, respectively; and forming a back metal layer on the second surface of the ferrite substrate, and forming an inner diameter metal layer of the via hole of the front ground pad and the via hole of the heat sink metal layer so that the back metal layer is electrically connected to the front ground pad and the heat sink metal layer. A method for manufacturing a microstrip type isolator including a heat sink is provided.

The concept of the present invention introduced above will be clearer through specific embodiments described later with drawings.

The present invention is a heat sink in a structure in which heat generated on the load resistor of a terminated port when driving a conventional microstrip type isolator is dissipated to the back metal layer, that is, the ground pad, in which the heat is bonded to the lower surface of the substrate of the device. By adding , a heat dissipation path is added not only in the rear direction of the ferrite substrate but also in the side direction of the ferrite substrate under the load resistance, thereby suppressing excessive temperature rise of the load resistance and the ferrite substrate when driving the microstrip type isolator, and abnormal driving of the device and failure can be prevented.

Figure 1: Structure of a prior art broadband antenna
Figure 2: A top view of an isolator of the prior art;
Figure 3: Cross-section (AA') of the isolator of the prior art.
Figure 4: a plan view of the microstrip type isolator according to the present invention;
5a to 8b: a manufacturing process diagram of a microstrip type isolator according to the present invention

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the preferred embodiments described in detail below in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described below and may be implemented in various other forms. The examples are only provided to completely disclose the present invention and to completely inform those of ordinary skill in the art to which the present invention pertains to the scope of the invention, and the present invention is defined by the claims will be.

In addition, the terminology used herein is for the purpose of describing the embodiment and is not intended to limit the present invention. In this specification, the singular also includes the plural unless otherwise specified. Also, as used herein, the term 'comprise (comprise, comprising, etc.)' refers to the presence or absence of one or more other components, steps, operations, and/or elements other than the stated elements, steps, operations, and/or elements. It is used in the sense of not excluding addition.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the embodiment, if a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

4 is a plan view showing the configuration of the microstrip type isolator device manufactured according to the present invention.

Overall, the structure is similar to that shown in FIG. 2 . That is, the circulator metal layer 100 is formed on the ferrite substrate 50 , and the port 3 is connected to the front ground pad 140 through the thin film-type load resistor 120 connected to the circulator metal layer 100 . In addition, a via hole 200 is formed in the front ground pad 140 . In addition, a pair of heatsink metal layers 250 are formed adjacent to the load resistor 120 . Via holes 260 are formed in each heat sink metal layer 250 .

Hereinafter, a method for manufacturing a microstrip type isolator including a heat sink on a ferrite substrate according to the present invention will be described.

FIG. 5A is a cross-sectional view taken along line AA′ of FIG. 4 , and FIG. 5B is a cross-sectional view taken along line BB′ of FIG. 4 . 5A and 5B, in order to form a via hole in a region where the front ground pad 140 and the heat sink metal layer 250 of the ferrite substrate 50 are to be formed, the substrate in the corresponding region is etched or removed. It can be seen that the via hole 260 for the heat sink metal layer 250 is etched in FIG. 5A . FIG. 5B is a cross-sectional view taken along line BB′ of FIG. 4 , and it can be seen that the via hole 200 for the front ground pad 140 is etched.

This step is to form a via hole structure for forming a heat sink as well as electrical connection between the rear ground pad (rear metal layer) and the front ground pad of the microstrip type isolator device based on the ferrite substrate used for manufacturing the microstrip type isolator. As a step, it begins with removing the substrate on the predetermined area where the via hole is to be formed. A ferrite substrate is _{a material having a basic composition such as 5Fe 2} O ₃ 3M ₂ O ₃ (M corresponds to a metallic ion), and basically has a ferrimagnetism characteristic. Etching or laser drilling may be used to remove the via hole region from the substrate.

Next, as shown in FIG. 6 , a thin film resistor layer 120 is deposited on a predetermined region where the load resistor 120 of FIG. 4 is to be formed, and a specific port (here, Port3) of the circulator 100 is deposited. A load resistor is formed for the termination treatment of The thin film resistance layer 120 may be a NiCr or TaN thin film, and may be deposited through a thermal evaporator, an E-beam evaporator, or a sputter process.

Subsequently, as shown in FIGS. 7A and 7B , the circulator metal layer 100 and the front ground pad 140 connected to the thin film resistance layer 120 for load resistance are formed on the substrate 50 , and a heat sink is formed. A heat sink metal layer 250 is formed in the region. To this end, a metal thin film layer is first deposited on the region where each metal layer and pad are to be formed, and a metal plating layer is plated on the metal thin film layer to form each metal layer and pad.

Specifically, as shown in FIG. 7A, a circulator metal layer 100 and a heat sink metal layer 250 are formed in a predetermined circulator region and a heat sink region of the first surface (front) of the ferrite substrate 50, respectively. First, a metal thin film layer is deposited. Then, a metal plating layer is formed on these metal thin film layers using an electrolytic plating process to finally form the circulator metal layer 100 and the heat sink metal layer 250 (however, in FIG. 140) is not represented). The metal thin film layer may be made of a material such as Ti/Cu, TiW/Cu, Ti/Au, Cr/Au, and the plating layer may be Cu or Au, and the thickness of the plating layer may be 1 to 20 μm.

Here, the heat sink metal layer 250 is not connected to any metal layer of the microstrip type isolator element on the front surface of the ferrite substrate 50, and only via holes with the metal layer 240 (see FIGS. 8a and 8b) on the rear surface of the substrate 50 (260) is connected through the inner diameter metal layer 280 of the sidewall.

FIG. 7B is a cross-sectional view taken along line B-B' of FIG. 4 , in which the circulator metal layer 100 , the thin film type resistance layer 120 for the load resistor, and the front ground pad 140 are represented. However, the heat sink metal layer 250 and its via hole 260 are not shown.

Next, a metal thin film layer is deposited to form a back metal layer 240 on the second surface (rear surface) of the ferrite substrate 50 as shown in FIGS. 8A (AA′ cross-sectional view) and 8B (BB′ cross-sectional view) Plating the plating layer. The back metal layer 240 of the second surface of the substrate is formed through the via hole 200 of the front ground pad 140 and the inner diameter metal layers 220 and 280 of the via hole 260 of the heat sink metal layer 250 of the first surface. It is connected to the front ground pad 140 and the heat sink metal layer 250 . Here, the material of the metal thin film layer and the plating layer may be the same material used in the metal thin film layer forming process and the plating layer forming process performed on the first surface of the substrate 50 , respectively.

Finally, if the above process forms a plurality of microstrip type isolator elements on one ferrite substrate, each element is separated through a sawing process.

Then, each microstrip type isolator element is packaged. In this packaging process, eutectic-bonding is performed to bond the device to the ground metal surface. In this eutectic bonding process, for example, an Au-Sn eutectic bonding process can be used.

As described above, according to the present invention, a heat sink is formed without a separate additional process and a heat dissipation path of the microstrip type isolator device is added, thereby suppressing the load resistance and excessive temperature rise of the ferrite substrate during device driving. can prevent abnormal operation and failure of

Although the present invention has been described in detail through preferred embodiments of the present invention, those of ordinary skill in the art to which the present invention pertains will not change the technical spirit or essential features of the present invention and differ from the contents disclosed in the present specification. It will be understood that the invention may be embodied in other specific forms. It should be understood that the embodiments described above are illustrative in all respects and not restrictive. In addition, the protection scope of the present invention is determined by the claims described below rather than the above detailed description, and all changes or modifications derived from the claims and their equivalent concepts should be interpreted as being included in the technical scope of the present invention. do.

Claims (18)

A microstrip type isolator comprising a circulator metal layer formed on a first surface of a ferrite substrate, a front ground pad connected to one of the ports of the circulator metal layer through a load resistor, and a heat sink metal layer formed adjacent to the load resistor A method of manufacturing
removing the area in the form of a via hole to form a via hole of the front ground pad and a via hole of the heat sink metal layer in the area where the front ground pad and the heat sink metal layer are to be formed on the first surface of the ferrite substrate;
forming a load resistor for terminating one of the ports of the circulator on the first surface of the ferrite substrate;
forming a circulator metal layer, a front ground pad, and a heat sink metal layer in the circulator area, the front ground pad area, and the heat sink metal layer area of the first surface of the ferrite substrate, respectively; and
Forming a back metal layer on the second surface of the ferrite substrate, and forming an inner diameter metal layer of the via hole of the front ground pad and the via hole of the heat sink metal layer so that the back metal layer is electrically connected to the front ground pad and the heat sink metal layer A method of manufacturing a microstrip type isolator including a heat sink. The microstrip type with a heat sink according to claim 1, further comprising the step of manufacturing a plurality of the microstrip type isolators on one ferrite substrate, and cutting and separating the plurality of microstrip type isolators A method for manufacturing an isolator. The method of claim 1, further comprising bonding the manufactured microstrip type isolator to a ground metal surface using eutectic-bonding in order to package the manufactured microstrip type isolator. A method for manufacturing a microstrip type isolator with a heat sink. [Claim 4] The method of claim 3, wherein an Au-Sn eutectic bonding process is used in the eutectic bonding. The method of claim 1 , wherein the ferrite substrate has a ferrimagnetism characteristic. The method of claim 1 , wherein laser drilling is used to remove the substrate into the via hole shape. The method of claim 1 , wherein an etching technique is used to remove the substrate in the shape of the via hole. The method of claim 1, wherein in the step of forming a circulator metal layer, a front ground pad, and a heat sink metal layer on the first surface of the ferrite substrate,
Microstrip with a heat sink, comprising first depositing a metal thin film layer in each of the regions where the circulator metal layer, the front ground pad, and the heat sink metal layer are to be formed, and forming a metal plating layer on the first deposited metal thin film layer A method for manufacturing a type isolator. The method of claim 1, wherein in the step of forming a back metal layer on the second surface of the ferrite substrate
A method for manufacturing a microstrip type isolator including a heat sink, comprising: first depositing a metal thin film layer in each region where the back metal layer is to be formed, and forming a metal plating layer on the first deposited metal thin film layer. a circulator metal layer formed on the first surface of the ferrite substrate;
a front ground pad connected to one of the ports of the circulator metal layer through a load resistor;
the front ground pad and a via hole formed therein;
a heat sink metal layer formed adjacent to the load resistor and a via hole formed therein; and
Including a back metal layer formed on the second surface of the ferrite substrate,
wherein the back metal layer is connected to the front ground pad and the heat sink metal layer through a via hole of the front ground pad and a via hole of the heat sink metal layer. The microstrip type isolator with a heat sink according to claim 10, wherein the ferrite substrate has a ferrimagnetism characteristic. The microstrip type isolator with a heat sink according to claim 10, wherein a plurality of the microstrip type isolators are manufactured on one ferrite substrate. The method of claim 10, wherein the via hole of the front ground pad and the via hole of the heat sink metal layer
A microstrip type isolator with a heat sink that is formed by removing the via hole area of a ferrite substrate using laser drilling. The method of claim 10, wherein the via hole of the front ground pad and the via hole of the heat sink metal layer
A microstrip type isolator with a heat sink that is formed by removing the via hole area of a ferrite substrate using an etching process. 11. The method of claim 10, wherein the circulator metal layer, the front ground pad, and the heat sink metal layer of the first surface of the ferrite substrate
Microstrip type including a heat sink, which is formed by first depositing a metal thin film layer on each of the circulator metal layer, the front ground pad, and the region where the heat sink metal layer is to be formed, and forming a metal plating layer on the first deposited metal thin film layer A method for manufacturing an isolator. 11. The method of claim 10, wherein the back metal layer of the second surface of the ferrite substrate
A microstrip type isolator including a heat sink, which is formed by first depositing a metal thin film layer in an area where the back metal layer is to be formed and forming a metal plating layer on the first deposited metal thin film layer. A microstrip type isolator package including a heat sink manufactured by bonding the microstrip type isolator of claim 10 to a ground metal surface using eutectic-bonding. The microstrip type isolator package including a heat sink according to claim 17, wherein an Au-Sn eutectic bonding process is used in the eutectic bonding.

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