JP4206185B2 - High frequency semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency semiconductor device configured by mounting and mounting a plurality of high-frequency semiconductor circuit elements that operate in a high-frequency band, and in particular, the high-frequency characteristics are excellent and individual high-frequency semiconductor circuit elements can be easily replaced. The present invention relates to a high-frequency semiconductor device that can easily improve the yield rate.
[0002]
[Prior art]
Generally, various high-frequency semiconductor circuit elements such as amplifiers, frequency converters, and oscillators are used in a high-frequency semiconductor device that constitutes a wireless unit in a communication device or a sensor. In a high frequency band higher than the microwave band, particularly in a frequency band higher than the millimeter wave band, as these semiconductor circuits, for example, a circuit having a monolithic integrated circuit (MMIC) configuration using a III-V group compound semiconductor such as gallium arsenide (GaAs). Elements are mainly used. Such a high-frequency semiconductor circuit element is used by being sealed in a semiconductor package for the purpose of protecting the circuit itself and facilitating the handling in the manufacturing process of the high-frequency device, or the radio unit or the entire device. It is used by being mounted on a carrier substrate (external electric circuit substrate) as a sealed state.
[0003]
Up to now, in order to reduce the influence of the non-defective product rate of the high-frequency semiconductor circuit element on the non-defective product rate of the entire high-frequency semiconductor device, a plurality of semiconductor circuit elements are each mounted on a semiconductor package or carrier substrate, After inspecting the characteristics, it was necessary to assemble the entire high-frequency semiconductor device. In this case, if a defective product is found in the inspection of each semiconductor circuit element, it is possible to obtain an advantage that only a high-frequency semiconductor circuit element that is a non-defective product can be used for assembling the entire high-frequency semiconductor device by removing it in the inspection process. .
[0004]
However, mounting each of the semiconductor circuit elements on the semiconductor package or carrier substrate for the inspection of the high-frequency semiconductor circuit element unit level in this way increases the number of parts, and increases the size of the entire high-frequency semiconductor device. There is a problem that. Further, in the connection between the semiconductor circuit elements, the interconnection between the semiconductor circuit element and the semiconductor package or the carrier substrate, or the interconnection between the semiconductor package or the carrier substrate, and further, the mother board or the connection substrate in the semiconductor package or the carrier substrate and the apparatus. As a result, there arises a problem that the high-frequency characteristics of the high-frequency semiconductor device are deteriorated.
[0005]
For this reason, in recent years, multi-chip mounting has been proposed in which a plurality of high-frequency semiconductor circuit elements are mounted on a single semiconductor package or carrier substrate, thereby reducing the number of components, downsizing the apparatus, and improving high-frequency characteristics. Yes. Such a mounting form is a mounting form that has been conventionally used when configuring a semiconductor device inside an information device such as a computer, but in recent years it is also being applied to a high-frequency semiconductor device inside a communication device.
[0006]
On the other hand, a high-frequency semiconductor device that constitutes a radio unit or the like of a communication device has a semiconductor circuit such as an oscillator or an amplifier as described above as a requirement of the device configuration, and among them, an oscillator used for the purpose of generating a carrier wave For the purpose of avoiding interference of unnecessary high frequency signals, the peripheral circuit part is a reception system circuit part composed of a low noise amplifier, a frequency converter and its peripheral circuit, and a transmission power amplifier, a frequency converter and a peripheral circuit thereof. In many cases, it is configured to be electrically isolated from the system circuit part. Therefore, it is desirable that the overall structure of the high-frequency semiconductor device has a configuration in which the reception system circuit part, the transmission system circuit part, and the oscillation circuit part are respectively housed in independent housing structures.
[0007]
In addition, in the high-frequency semiconductor device as described above, when performing multi-chip mounting for the purpose of reducing the number of components, downsizing the device, and improving high-frequency characteristics, a semiconductor having a structure capable of mounting a plurality of high-frequency semiconductor circuit elements It is necessary to realize the package or carrier substrate as a structure having a plurality of housing structures that can electrically isolate the receiving system circuit part, the transmitting system circuit part, and the oscillation circuit part as described above.
[0008]
As a conventional example of such a structure, a plurality of frames made of iron-nickel-cobalt alloy or the like are joined on a metal base such as iron-nickel-cobalt alloy by silver brazing or the like, and according to the configuration of the radio circuit. In order to realize the connection, a notch is provided in a part of the corresponding frame, and an input / output connection component having a microstrip line / strip line / microstrip line conversion structure is fitted and bonded to the notch. There is a so-called metal wall package having such a structure.
[0009]
In such a multi-chip package using a metal wall package, each semiconductor circuit element is individually evaluated, and only a semiconductor circuit element that has been confirmed to be non-defective is used. A structure that realizes electrical connection with the outside of the frame body by being mounted on and interconnecting the electrodes of the semiconductor circuit element directly to the input / output connection component or via a line substrate with a gold ribbon or gold wire, etc. It has become.
[0010]
[Problems to be solved by the invention]
However, the metal wall package as described above has a structure in which input / output connection parts are fitted and bonded to the notch provided in the frame body, so that airtightness is ensured and good high frequency is achieved. In order to realize the characteristics, there is a problem that high machining accuracy is required and the manufacture becomes difficult. In addition, parts that can be used particularly in a high-frequency band such as millimeter waves have a low yield rate in manufacturing, which generally increases the manufacturing cost.
[0011]
The present invention has been made in view of the above-described problems in the prior art, and the object thereof is to achieve desired inter-frequency semiconductor circuit elements while realizing multichip mounting for the purpose of reducing the number of components and downsizing the apparatus. It is an object of the present invention to provide a high-frequency semiconductor device capable of electrically isolating the above and realizing good high-frequency characteristics and reducing the manufacturing cost.
[0012]
[Means for Solving the Problems]
The high-frequency semiconductor device of the present invention is provided with a plurality of mounting portions in which electrode wirings to which electrodes of a plurality of high-frequency semiconductor circuit elements are electrically connected are formed on the upper surface of a dielectric substrate, and each of the mounting portions has a high-frequency semiconductor circuit. A dielectric in which an element is mounted and its electrode is electrically connected to the electrode wiring, and a plurality of concave portions corresponding to the mounting portion are provided on the lower surface of the dielectric substrate, and a connection wiring is formed between the concave portions. A body lid is attached, the high-frequency semiconductor circuit element is accommodated in the recess for each mounting portion, and the electrode wirings between the mounting portions are electrically connected by the connection wiring. To do.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
According to the high frequency semiconductor device of the present invention, due to the above configuration, the inspection by the characteristic evaluation of each high frequency semiconductor circuit element is performed by using the dielectric lid in a state where the high frequency semiconductor circuit element is mounted on the dielectric substrate. The high frequency semiconductor device can be completed by attaching the dielectric lid on the dielectric substrate after confirming that each mounted high frequency semiconductor circuit element is a non-defective product. At this time, a region for connection with the connection wiring provided at the end of the electrode wiring electrically connected to the electrode of each high-frequency semiconductor circuit element housed in the recess formed in the dielectric lid, and the dielectric An electrical connection is made by bonding the connection area with the electrode wiring provided at the end of the connection wiring for electrically connecting the recesses formed on the lower surface of the body lid with a conductive adhesive or the like. By configuring the high-frequency circuit by realizing electrical connection between the high-frequency semiconductor circuit elements accommodated in the recesses, for example, an oscillation circuit, a reception system circuit, a transmission system circuit, etc. It can be electrically isolated by storing in the recess. Therefore, the number of non-defective parts that can be used in the high-frequency band such as millimeter waves is low, and the number of parts is reduced and the equipment is downsized compared to the case of using a metal wall package that has a high manufacturing cost. To provide a high-frequency semiconductor device that realizes good high-frequency characteristics by electrically isolating desired high-frequency semiconductor circuit elements while realizing multi-chip mounting for the purpose, and that can keep manufacturing costs low Can do.
[0014]
Hereinafter, a high-frequency semiconductor device of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is an exploded perspective view showing a schematic configuration of an example of an embodiment of a high-frequency semiconductor device according to the present invention. In FIG. 1, reference numeral 1 denotes a dielectric substrate, and reference numerals 41 and 42 denote high-frequency semiconductor circuit elements mounted and mounted on a mounting portion provided on the upper surface of the dielectric substrate 1. The input / output electrodes (not shown) of the plurality of high-frequency semiconductor circuit elements 41 and 42 have the same ground conductor on both sides of the signal conductor and the signal conductor on the lower surface of the element so that the evaluation by the wafer probe can be performed. It has the form of a coplanar line formed on a plane.
[0016]
101 to 103, 111 to 113, 121 to 123, and 131 to 133 are electrode wirings formed on the mounting portion on the upper surface of the dielectric substrate 1 to which the electrodes of the high-frequency semiconductor circuit elements 41 and 42 are electrically connected. It is. Here, corresponding to the electrodes of the high-frequency semiconductor circuit elements 41 and 42 in the form of a coplanar line, signal electrodes 101, 111, 121, and 131 formed as high-frequency line conductors and grounding electrodes on both sides thereof 102, 103, 112, 113, 122, 123, 132, 133 are formed. The characteristic impedance of the coplanar line formed by these signal electrodes 101, 111, 121, 131 and the ground electrodes 102, 103, 112, 113, 122, 123, 132, 133 formed on the dielectric substrate 1 is It is determined by the thickness and relative dielectric constant of the dielectric substrate 1, the width of the signal electrode, and the distance between the signal electrode and the ground electrode. Usually, the value is determined so as to match the characteristic impedance of the input / output electrodes of the high-frequency semiconductor circuit elements 41 and.
[0017]
In the mounting portion on the top surface of the dielectric substrate 1, the high-frequency semiconductor circuit elements 41 and 42 may be mounted on the same surface as the substrate surface, or may be mounted in a recess formed on the top surface of the substrate. The electrical connection between the high-frequency semiconductor circuit elements 41 and 42 and the respective electrode wirings 101 to 103, 111 to 113, 121 to 123, and 131 to 133 may be performed by wire bonding or by a so-called flip chip mounting method. Also good.
[0018]
Reference numeral 2 denotes a dielectric lid, and reference numerals 31 and 32 denote recesses 31 and 32 provided on the lower surface of the dielectric lid 2 and having an opening on the lower surface. The plurality of recesses 31 and 32 are mounted in a state where the dielectric lid 2 is attached to the dielectric substrate 1 after the high-frequency semiconductor circuit elements 41 and 42 are mounted on the respective mounting portions on the upper surface of the dielectric substrate 1. Each part is formed in a position and a size in which the high-frequency semiconductor circuit elements 41 and 42 are accommodated.
[0019]
Reference numerals 201 to 203 denote connection wirings formed between the recesses 31 and 32 on the lower surface of the dielectric lid 2. These connection wirings 201 to 203 are electrically connected to the electrode wirings 111 to 113 and 121 to 123 of the mounting portions 31 and 32 on both ends, respectively, so that the electrode wirings 111 to 113. It is formed as a high-frequency line conductor at a position where 121 to 123 are electrically connected to each other. Here, corresponding to the electrode wirings 111 to 113 and 121 to 123 in the form of coplanar lines, signal electrodes 201 and grounding electrodes 202 and 203 as high-frequency line conductors are formed. Thus, in a state where the dielectric lid 2 is attached to the dielectric substrate 1, as shown in a perspective view of the main part in FIG. 2, the signal electrodes 111 and 121 of the electrode wiring formed on the dielectric substrate 1 are provided. , And the grounding electrodes 112, 122, 113, and 123 are electrically connected to each other by contacting the signal electrode 201 and the grounding electrodes 202, 203 of the connection wiring. Each of these abutting portions may be used in combination with solder, a conductive adhesive or the like in order to make the electrical connection more reliable.
[0020]
In this example, illustration of connection with other connection wirings or external electric circuit boards to which the electrode wirings 101 to 103 and 131 to 133 are electrically connected is omitted.
[0021]
According to the above configuration, before the dielectric lid 2 is attached, the electrode wiring formed on each mounting portion on the dielectric substrate 1, that is, the signal electrodes 111 and 121, the ground electrode 112, 122, 113, and 123 are separated from each other, and by connecting these electrode sets with a wafer probe, each high-frequency semiconductor circuit element 41, 42 having an electrode connected to each electrode wiring is connected to each mounting part. It becomes possible to evaluate independently. When the dielectric lid 2 is attached to the dielectric substrate 1 after evaluating the high-frequency semiconductor circuit elements 41 and 42 and confirming that they are non-defective, the dielectric lid 2 is formed on the dielectric lid 2. The connection wiring, that is, the signal electrode 201 and the grounding electrodes 202 and 203 electrically connect the electrode wirings between the mounting portions on the dielectric substrate 1, that is, the signal electrodes 111 and 121, and the grounding electrodes 112 and 122, 113, and 123, respectively. Will be connected. At this time, the relative permittivity of the dielectric lid 2, the thickness of the portions other than the recesses 31 and 32, the width of the signal electrode 201, and the interval between the signal electrode 201 and the ground electrodes 202 and 203 are as follows: In the state after 2 is attached to the dielectric substrate 1, the characteristic impedance of the coplanar line constituted by the signal electrodes 111 and 121 and the ground electrodes 112, 122, 113 and 123 formed on the dielectric substrate 1 By determining the respective values so as to match each other, the high-frequency semiconductor circuit elements 41 and 42 are electrically isolated from each other between the mounting parts, and good high-frequency transmission characteristics are realized in the interconnection between them. It becomes possible.
[0022]
In the high-frequency semiconductor device of the present invention, the dielectric substrate 1 can be made of various dielectric materials conventionally used for semiconductor packages, carrier substrates and the like. Specific dielectrics include various ceramics and glass ceramics such as aluminum oxide sintered bodies and aluminum nitride sintered bodies, or organic resin dielectrics such as PTFE, glass epoxy and polyimide. Can do. In particular, when a material that can be hermetically sealed, such as ceramics such as an aluminum oxide sintered body or an aluminum nitride sintered body, is used, a high-frequency semiconductor circuit element can be obtained by using the same material for the lid. It becomes possible to store the air and seal hermetically well.
[0023]
The mounting portion and the electrode wirings 101 to 103, 111 to 113, 121 to 123, and 131 to 133 may be configured according to the mounting form of the high frequency semiconductor circuit elements 41 and 42 to be mounted. For example, in the case where a high-frequency semiconductor circuit element and an external circuit are connected to each other using wire bonding technology, a die attach pattern is formed on the surface of the dielectric substrate 1, and the high-frequency semiconductor to be mounted. A signal electrode and a ground electrode may be provided at positions corresponding to the input / output electrodes of the circuit elements 41 and 42. In addition, if flip-chip technology is used to connect the high-frequency semiconductor circuit elements 41 and 42 to external circuits, it corresponds to the input / output electrodes of the high-frequency semiconductor circuit elements 41 and 42 to be mounted. A signal electrode and a ground electrode may be provided at the position where the signal is to be applied.
[0024]
The dielectric lid 2 may be made of a dielectric material or the like that can be produced by a laminating method in order to provide a concave portion. As a specific dielectric, for example, an aluminum oxide sintered material is used in the same manner as the dielectric substrate 1. Various ceramics and glass ceramics such as an aluminum body and an aluminum nitride sintered body, or an organic resin dielectric material as described above can be used. In particular, when materials that can be hermetically sealed, such as ceramics such as aluminum oxide sintered bodies and aluminum nitride sintered bodies, are used, the high-frequency semiconductor circuit element is accommodated as described above to provide a good airtightness. Can be achieved. If a dielectric material having a dielectric constant lower than that of the dielectric material used in the dielectric substrate 1 is used, electrode wiring before and after the dielectric lid 2 is attached to the dielectric substrate 1 This also has the effect of suppressing changes in impedance.
[0025]
The recesses 31 and 32 formed on the lower surface of the dielectric lid 2 are provided at positions where the high frequency semiconductor circuit elements 41 and 42 can be accommodated when the dielectric lid 2 is attached to the dielectric substrate 1. The space formed by the concave portions 31 and 32 of the dielectric lid 2 and the surface of the dielectric substrate 1 after the dielectric lid 2 is attached may be larger than the volume of the high-frequency semiconductor circuit elements 41 and 42 to be accommodated. It is desirable to set as small as possible so that unnecessary resonance or the like does not occur. In addition, a through conductor such as a via hole is disposed around the recesses 31 and 32 in the dielectric lid 2 so as to surround at a sufficiently small interval with respect to the in-tube wavelength corresponding to the operating frequency. By forming a conductor that is electrically connected to the via hole and also to the ground of the semiconductor device on the surface of the metal, the electromagnetic shielding effect of the recesses 31 and 32 that accommodate the high-frequency semiconductor circuit elements 41 and 42 is provided. It becomes possible.
[0026]
For example, in the case of ceramics, the concave portions 31 and 32 may be formed by laminating a layer provided with a hollow portion by punching or laser processing at a so-called green sheet stage before firing. In the case of an organic resin material, it is also possible to form the recesses 31 and 32 by laminating a layer provided with a hollow portion or by using a chemical process such as etching.
[0027]
The connection wirings 201 to 203 may have the same line width and distance as the electrode wiring, and the shorter the wiring length, the better. However, the wiring length depends on the distance between the recesses 31 and 32. The mechanical strength of the dielectric lid 2 may be shortened as long as no deterioration occurs.
[0028]
【Example】
Next, specific examples of the high-frequency semiconductor device of the present invention will be described.
[0029]
Two high-frequency semiconductor circuit element mounting portions are provided on the upper surface of a dielectric substrate 1 made of alumina ceramics having a thickness of 0.2 mm and a relative dielectric constant of 8.8, and signal electrodes 111 and 121 each having a width of 0.13 mm are formed. Electrode wirings in the form of coplanar lines were produced by forming grounding electrodes 112, 113, 122, 123 having a width of 0.2 mm on both sides at intervals of 0.065 mm. At this time, the characteristic impedance of the coplanar line was set to about 50 ohms.
[0030]
A recess for accommodating a high-frequency semiconductor circuit element corresponding to the mounting portion of the dielectric substrate 1 is formed on the lower surface of the dielectric lid 2 made of a glass ceramic substrate having a thickness of 1.0 mm and a relative dielectric constant of 4.9. A signal electrode 201 having a width of 0.17 mm was formed between the recesses, and ground electrodes 202 and 203 having a width of 0.2 mm were formed on both sides thereof at intervals of 0.05 mm.
[0031]
Then, the dielectric lid 2 is attached on the dielectric substrate 1 so that the recesses and the mounting portions correspond to each other, and the signal electrode 201 and the ground electrodes 202 and 203 formed on the lower surface of the dielectric lid 2. The parts where each end overlaps with each end of the signal electrodes 101 and 111 and the ground electrodes 112, 113, 122, and 123 formed on the upper surface of the dielectric substrate 1 are bonded together by soldering. The transmission line structure in the high-frequency semiconductor device of the present invention was formed in which the electrode wirings were electrically connected by connection wiring.
[0032]
The transmission characteristics of high frequency signals in this transmission line structure were measured using a network analyzer. The results are shown graphically in FIG. In FIG. 3, the horizontal axis represents the frequency (unit: GHz), the vertical axis represents the logarithm of the absolute values of the S parameters S11 and S21 (unit: dB), and the broken line in the characteristic curve represents the frequency characteristic of S11. The solid line indicates the frequency characteristic of S21. As can be seen from this result, the reflection coefficient S11 is kept low over a wide band, while it has a very good transmission characteristic as shown by the characteristic curve of S21 indicating the pass characteristic.
[0033]
Furthermore, the electrical isolation state between the mounting parts of the structure sealed by the corresponding recesses 31 and 32 is accommodated in the recesses 31 and 32 arranged so that the transmission system circuit part and the oscillation circuit part are close to each other. When each high-frequency semiconductor circuit element is operated in a state where they are close to each other, each high-frequency semiconductor circuit element operates normally and also operates normally as a transmitter. It was confirmed that 31 and 32 were electrically isolated well. As a result, it was confirmed that the mounting portions can be arranged close to each other on the dielectric substrate 1 and the high-frequency semiconductor device can be further reduced in size.
[0034]
Note that the above are merely examples of the embodiments of the present invention, and the present invention is not limited to these embodiments, and various modifications and improvements may be added without departing from the scope of the present invention. . For example, in the above example, an example in which one high-frequency semiconductor circuit element is mounted and mounted in each mounting portion and each recess is shown. However, a plurality of high-frequency semiconductor circuit elements are provided according to the specifications of the high-frequency circuit. It goes without saying that can be mounted and accommodated.
[0035]
【The invention's effect】
As described above, according to the high-frequency semiconductor device of the present invention, a plurality of mounting portions in which electrode wirings to which the electrodes of a plurality of high-frequency semiconductor circuit elements are electrically connected are provided on the upper surface of the dielectric substrate. A high-frequency semiconductor circuit element is mounted on each mounting portion, and the electrode is electrically connected to the electrode wiring. On the dielectric substrate, a plurality of recesses corresponding to the mounting portion are provided on the lower surface, and connection wiring is provided between the recesses. Since the dielectric lid body formed by attaching the high-frequency semiconductor circuit element in the recess for each mounting portion and electrically connecting the electrode wirings between the mounting portions with the connection wiring, the following It has such an advantageous effect.
[0036]
First, the inspection by the characteristic evaluation of each high-frequency semiconductor circuit element is performed at the stage where the high-frequency semiconductor circuit element is mounted on the dielectric substrate and before the dielectric lid is mounted. After confirming that the semiconductor circuit element is a non-defective product, the dielectric lid is attached onto the dielectric substrate, whereby the high-frequency semiconductor device can be completed.
[0037]
In addition, a recess formed on the lower surface of the dielectric lid between the mounting portions between the electrode wirings electrically connected to the electrodes of each high-frequency semiconductor circuit element housed in the recess formed in the dielectric lid. By electrically connecting with the connection wiring for electrically connecting each other, electrical connection between each high-frequency semiconductor circuit element accommodated in the recess is realized to constitute a high-frequency circuit, and each mounting It is possible to electrically isolate the portions, that is, the recesses, from each other satisfactorily.
[0038]
Therefore, compared to conventional high-frequency semiconductor devices using a multi-chip package or the like, while realizing multi-chip mounting for the purpose of reducing the number of parts and downsizing the device, the desired high-frequency semiconductor circuit elements can be electrically connected. Therefore, it is possible to provide a high-frequency semiconductor device that achieves good high-frequency characteristics and can be manufactured at a low cost.
[0039]
In addition, since the high-frequency semiconductor circuit element for each mounting portion can be sealed and the electrical connection between the high-frequency semiconductor circuits can be performed simultaneously by attaching the dielectric lid, there is also an advantageous manufacturing effect such as reduction in the number of assembly steps. Is.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a schematic configuration of an example of an embodiment of a high-frequency semiconductor device of the present invention.
2 is a perspective view of a main part showing a state in which a dielectric lid is attached to a dielectric substrate in the high-frequency semiconductor device shown in FIG.
FIG. 3 is a diagram showing reflection characteristics and transmission characteristics of a transmission line structure by electrode wiring and connection wiring in the high-frequency semiconductor device of the present invention.
[Explanation of symbols]
1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Dielectric substrate
101, 111, 121, 131 ..... Signal electrode (electrode wiring)
102, 103, 112, 113, 122, 123, 132, 133 ... Grounding electrode (electrode wiring)
2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Dielectric lid
31, 32 ...
201 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Signal electrode (connection wiring)
202, 203 ... Grounding electrode (connection wiring)
41, 42 ... ・ ・ ・ ・ ・ High frequency semiconductor circuit elements

Claims (1)

A plurality of mounting portions having electrode wirings electrically connected to electrodes of a plurality of high-frequency semiconductor circuit elements are provided on the upper surface of the dielectric substrate, and the high-frequency semiconductor circuit elements are mounted on the respective mounting portions and the electrodes are mounted Electrically connecting to the electrode wiring, and providing a plurality of recesses corresponding to the mounting portion on the lower surface of the dielectric substrate, and attaching a dielectric lid having connection wires formed between the recesses; The high-frequency semiconductor device is characterized in that the high-frequency semiconductor circuit element is accommodated in the recess for each mounting portion, and the electrode wirings between the mounting portions are electrically connected by the connection wiring.

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