JPH11265961A - Surface-mounting type wiring substrate for high frequency - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the junction reliability without adverse effects on the high-frequency characteristics by increasing the junction area of a wiring substrate and an external electric circuit substrate and increasing the junction strength without imparting the electric adverse effects on the high-frequency signal, which is transmitted on a high-frequency transmission path. SOLUTION: A mounting part 21a, on which a semiconductor element for high frequencies is mounted, is formed in an insulating base body 21 comprising ceramics. At the same time, a high-frequency transmitting path 22, which is guided out from the vicinity of the mounting part 21a to the lower surface of the insulating base body 21, is formed. The end part of the path is connected to the wiring conductor at the surface of the external electric circuit substrate through a conductive connecting member. In this high-frequency surface mounting type wiring substrate, a reinforcing pad 23, which reinforces the junction with the external electric circuit substrate, is formed at the position, which is separated by 1.5 mm or more from the high-frequency transmission part 32 at the lower surface of the insulating base body 21. The junction strength can be enhanced with the external electric circuit substrate without deteriorating the high frequency characteristics, the substrate is suitable for the high-frequency semiconductor device and connecting reliability becomes high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for a surface-mounted type high-frequency semiconductor element storage package or high-frequency semiconductor device used for communication equipment or sensors using high frequencies such as microwaves and millimeter waves. The present invention relates to a high-frequency surface-mounted wiring board, and more particularly to a high-frequency surface-mounted wiring board having improved connection reliability with an external electric circuit board.

[0002]

2. Description of the Related Art A high-frequency semiconductor device equipped with a high-frequency semiconductor element such as a high-frequency circuit element for handling a high-frequency signal such as a microwave or a millimeter wave usually includes a high-frequency semiconductor substrate on an insulating base made of a dielectric material such as ceramics. A high-frequency semiconductor element is housed in a surface-mount type high-frequency semiconductor element housing package in which a mounting part on which a semiconductor element is mounted and a high-frequency transmission line led out from the mounting part to the lower surface of the insulating base are formed. It consists of. The high-frequency semiconductor device is mounted on a surface of a predetermined external electric circuit board, and a high-frequency transmission line or a connection terminal formed at an end thereof and a wiring conductor such as a high-frequency transmission line formed on the external electric circuit board. Are electrically connected to each other by a conductive connection member such as a solder bump, so that high-frequency signals are input and output between the high-frequency semiconductor element and the external electric circuit board.

A high-frequency surface-mounted wiring board used for such a high-frequency semiconductor device or a high-frequency semiconductor element housing package has a package structure capable of inputting and outputting signals without deteriorating high-frequency signals. It is required that the wiring structure such as a high-frequency transmission line be easily designed and manufactured, and that it be easy to cope with a mounting technology for accurately mounting a high-frequency semiconductor device on an external electric circuit board.

As this type of high-frequency semiconductor device, for example, a device as shown in a partially broken perspective view in FIG. 4 has been used. As shown in FIG. 4, a conventional high-frequency semiconductor device includes an insulating base 1 made of a dielectric material having a cavity 1a as a mounting portion on which a high-frequency semiconductor element is mounted, and an insulating base 1 near the cavity 1a. A wall member 3 is joined to a wiring board composed of a microstrip line or other high-frequency transmission line 2 formed over the end of the cavity 1 so as to surround the cavity 1a, and the high-frequency semiconductor element 4 is mounted in the cavity 1a. The electrode and the high-frequency transmission line 2 are connected by a bonding wire 5 and a lid (not shown) is attached to the upper surface of the wall member 3 to hermetically seal the high-frequency semiconductor element 4 therein. ing.

The high-frequency semiconductor device is mounted in a recess 6a provided on the surface of the external electric circuit board 6, and the high-frequency transmission line 2 passing through the wall member 3 and drawn out of the cavity 1a is connected to the external electric circuit. Wiring conductor 7 on the surface of circuit board 6
Are electrically connected to each other using a means such as wire bonding 8 to input and output a high-frequency signal.

[0006]

However, in the high-frequency semiconductor device as shown in FIG. 4, surface mounting on an external electric circuit board is impossible, so that high-density mounting cannot be achieved. Also, the cost of mounting cannot be reduced.

Therefore, in order to meet the demand for high-density mounting on an external electric circuit board and reduction in mounting cost, a high-frequency transmission line is formed on the lower surface of the insulating base of the wiring board, and the end or end of the high-frequency transmission line is formed. A surface-mount type high-frequency semiconductor device in which a connection terminal formed in a portion is directly joined to a wiring conductor on the surface of an external electric circuit board by a conductive connection member such as a solder bump has been proposed and used.

In such a surface-mount type high-frequency semiconductor device, as shown in, for example, a partially cutaway perspective view in FIG. A first high-frequency transmission line 12a, such as a microstrip line, formed up to the vicinity of the side wall 13 on the outer periphery of the substrate and a second high-frequency transmission line 12b, such as a microstrip line formed on the lower surface of the insulating base 11, are penetrated by a through conductor. By connecting at 14, the high-frequency transmission line is led out from the vicinity of the cavity 11a to the lower surface of the insulating base 11.

The electrode of the high-frequency semiconductor element 15 mounted in the cavity 11a and the first high-frequency transmission line 12
is connected by a bonding wire 16, and the second high-frequency transmission line 12b and a wiring conductor on the surface of an external electric circuit board (not shown) are joined by a conductive connection member (not shown) such as a solder bump. As a result, the high-frequency semiconductor device has been surface-mounted on an external electric circuit board.

In a wiring board used in such a surface-mount type semiconductor device, a second high-frequency transmission line 12b is extended on a side surface of an insulating base 11, so that the high-frequency semiconductor device and an external electric circuit are connected. An end face pattern 17 for ensuring bonding to a substrate by soldering or the like has also been provided.

However, a high frequency semiconductor device generally has a small number of terminals for connection to an external electric circuit board.
Moreover, when the conventional surface-mount type high-frequency semiconductor device is surface-mounted, the second high-frequency transmission line 12b formed on the lower surface of the insulating base 11 of the wiring board and the wiring conductor on the surface of the external electric circuit board are required. The bonding area between the insulating substrate 11 and the external electric circuit board is not sufficient due to the small bonding area between the insulating substrate 11 and the external electric circuit board.
Since the thermal expansion coefficient of the external electric circuit board generally made of organic resin or the like is different, the joint between the high-frequency transmission line 12b and the wiring conductor is broken in a short time, so that sufficient connection reliability cannot be obtained. There was a problem.

As shown in FIG. 5, when the wiring board is provided with a side pattern 17 for ensuring the reliability of bonding to an external electric circuit board, the side pattern 17 serves as a stub in a high-frequency circuit. Since it functions, a high-frequency signal is reflected at that portion, deteriorating high-frequency characteristics, and cannot be used in a high-frequency semiconductor device used in a frequency band of 10 GHz or more.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to improve the connection strength between a wiring board and an external electric circuit board without deteriorating high-frequency characteristics. An object of the present invention is to provide a high-frequency surface-mounted wiring board which is highly reliable and suitable for a high-frequency semiconductor element storage package or high-frequency semiconductor device.

[0014]

According to a first high-frequency surface mount type wiring board of the present invention, a mounting portion for mounting a high-frequency semiconductor element is formed on an upper surface or a lower surface of an insulating base made of ceramics. A high-frequency transmission line led from the vicinity of the mounting portion to the lower surface of the insulating base is formed, and an end of the high-frequency transmission line is joined to a wiring conductor on the surface of the external electric circuit board via a conductive connection member. Surface mounting type wiring board, wherein a reinforcing pad for reinforcing bonding with the external electric circuit board is formed on a lower surface of the insulating base at a position separated from the high-frequency transmission line by 1.5 mm or more. It is characterized by the following.

According to a second high-frequency surface-mount wiring board of the present invention, in the high-frequency surface-mount wiring board having the above structure, the mounting portion is formed on an upper surface of the insulating base, and A first high-frequency transmission line formed on an upper surface of the insulating base, and a second high-frequency transmission line formed on the lower surface of the insulating base so as to face the first high-frequency transmission line. And a ground conductor layer formed inside the insulating base, and formed with a slot hole corresponding to an opposing position of the first high-frequency transmission line and the second high-frequency transmission line, The first high-frequency transmission line and the second high-frequency transmission line are electromagnetically coupled via the slot hole.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to a first high-frequency surface-mount wiring board of the present invention, a high-frequency transmission line joined to a wiring conductor of an external electric circuit board formed on a lower surface of an insulating base is provided. , 1.5 mm in the line width direction when formed on the side, and in the line length direction when formed on the extension.
Since the reinforcing pad for reinforcing the connection with the external electric circuit board is formed at the above-mentioned distant position, it is necessary to bond the reinforcing pad and the corresponding connection pad provided on the external electric circuit board. As a result, the bonding strength between the wiring board and the external electric circuit board can be increased without adversely affecting the high-frequency signal propagating through the high-frequency transmission line, thereby increasing the bonding strength. It is possible to increase the joining reliability without exerting any influence.

According to the second high-frequency surface mount type wiring board of the present invention, the high-frequency transmission line led out from the mounting portion on the upper surface of the insulating base to the lower surface of the insulating base is mounted on the upper surface of the insulating base in the vicinity of the mounting portion. And a second high-frequency transmission line formed on the lower surface of the insulating base so as to face the first high-frequency transmission line, and formed inside the insulating base. And a first high-frequency transmission line and a second high-frequency transmission line.
And a ground conductor layer in which a slot hole is formed corresponding to a position facing the high-frequency transmission line. The first high-frequency transmission line and the second high-frequency transmission line are interposed through the slot hole. Because of the electromagnetic coupling, the first high-frequency transmission line on the upper surface of the insulating base passes through the wall member or the side wall of the lid joined to the upper surface of the insulating base for hermetic sealing of the high-frequency semiconductor element. The connection can be made at a high frequency to the second high-frequency transmission line on the lower surface of the insulating base without using the through conductor such as a through-hole conductor or a via conductor provided inside the insulating base. Therefore, there is no occurrence of reflection loss or radiation loss due to conversion of the high-frequency transmission line from the microstrip line to the stripline in the side wall passage portion, and there is no influence of transmission loss due to the through conductor. A high-frequency signal can be transmitted while suppressing transmission loss from the first high-frequency transmission line on the upper surface of the insulating base to the second high-frequency transmission line on the lower surface, and the connection between the wiring board and the external electric circuit board can be performed. High frequency characteristics can be further enhanced while increasing the strength.

That is, according to the surface mounting type wiring board for high frequency wave of the present invention, by providing the reinforcing pad as described above, the bonding strength between the wiring board and the external electric circuit board is reduced by the reinforcing pad. Therefore, higher bonding reliability can be obtained as compared with the conventional case where there is no reinforcing pad. Moreover, providing a conductive pattern other than the transmission line, such as a reinforcing pad, near the high-frequency transmission line is usually performed even if the conductive pattern is not DC-connected to the high-frequency transmission line. If stubs are provided as a high-frequency circuit, the same result will result in deterioration of the high-frequency transmission characteristics of the high-frequency transmission line, but as a result of the inventor's intensive studies, particularly When a high-frequency signal to be used is 10 GHz or more and 100 GHz or less, the line length direction is formed when the signal is formed beside a high-frequency transmission line such as a microstrip line as in the present invention, and the line length is formed when the signal is formed on an extension. If the reinforcing pads are provided at a distance of 1.5 mm or more in each direction, the reinforcing pads and the high-frequency transmission line will not be coupled at high frequencies, and It has been found that this does not cause deterioration of the performance, and has led to the realization of a high-reliability and high-performance surface mount type wiring board for high frequency with good high frequency characteristics while increasing the bonding strength with the external electric circuit board. is there.

Further, according to the second high-frequency surface-mount wiring board of the present invention, the high-frequency transmission line is provided inside the insulating base for leading the high-frequency transmission line from the mounting portion of the high-frequency semiconductor element on the upper surface of the insulating base to the lower surface. The use of a configuration of electromagnetic coupling via a ground conductor layer having a slotted hole has extremely good high-frequency characteristics that can withstand the use of high frequencies up to about 100 GHz, and is suitable for a high-frequency semiconductor device. It becomes a surface mount type wiring board.

In the high frequency surface mount type wiring board of the present invention, the reinforcing pad formed on the lower surface of the insulating base is located at an arbitrary position on the lower surface of the insulating base if it is at least 1.5 mm away from the high frequency transmission line. Can be formed,
In order for the reinforcing pads to more effectively counter the stress between the wiring board and the external electric circuit board, if the insulating base is rectangular so that the stress is applied most to these reinforcing pads, the It is preferable to form them at the four corners.

Since the reinforcing pads are provided at the four corners of the insulating base as described above, thermal stress between the wiring board and the external electric circuit board is applied most to these reinforcing pads. The wiring board has a bonding strength enough to withstand stress, and higher connection reliability can be obtained.

The high frequency surface mount type wiring board of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 (a) to 1 (c) are a bottom view, a transverse sectional view, and a vertical sectional view, respectively, showing an example of an embodiment of a high frequency surface mount type wiring board according to the present invention.

In FIG. 1, reference numeral 21 denotes an insulating base made of ceramic, and reference numeral 21a denotes a mounting portion for mounting a high-frequency semiconductor element formed on the upper surface of the insulating base 21. In this example, the mounting portion 21a is formed in a concave portion provided on the upper surface of the insulating base 21, but the mounting portion 21a may be formed on a flat surface or on the lower surface of the insulating base 21.

The ceramics suitably used for the insulating base 21 of the high-frequency surface-mount type wiring board of the present invention include, for example, alumina ceramics (tungsten oxide) having tungsten as an internal wiring which is widely used as a package for housing semiconductor elements. Sintered body). Also,
In order to reduce transmission loss at higher frequencies, low-temperature fired ceramics using silver, gold, copper, or the like as a wiring material can be used.

Reference numeral 22 denotes a high-frequency transmission line for transmitting a high-frequency signal derived from the vicinity of the mounting portion 21a to the lower surface of the insulating base 21. In this example, a microstrip line structure is shown on the lower surface of the insulating base 21, and a portion from the vicinity of the mounting portion 21a to the lower surface of the insulating base 21 is omitted. The ends of the high-frequency transmission line 21 are directly connected, or the connection terminals connected to the ends or the ends of the coplanar lines converted from the ends are connected to conductive connecting members such as solder bumps, silver solder bumps, and gold bumps. By being joined to the wiring conductor on the surface of the external electric circuit board (not shown) by (not shown), this wiring board is surface-mounted on the external electric circuit board.

As such a high-frequency transmission line 22,
A coplanar line, a strip line, a coplanar line with ground, and the like can also be used. The structure for leading the high-frequency transmission line 22 from the vicinity of the mounting portion 21a to the lower surface of the insulating base 21 includes a wiring conductor layer or the inside of the insulating base 21 as the high-frequency transmission line 22 formed inside or on the side surface of the insulating base 21. A penetrating conductor such as a penetrating through-hole conductor or via conductor may be employed. In addition, from the vicinity of the mounting portion 21a, it passes through the hermetic seal portion of the wall member attached to the upper surface of the insulating base 21 so as to surround the mounting portion 21a, and wraps around the side surface of the insulating base 21 to form the lower surface of the insulating base 21. May be derived.

The high-frequency transmission line 22 is made of a high-melting metal such as tungsten or molybdenum and plated with nickel or gold, or a thick-film conductor such as silver / silver-palladium or gold-plated copper. A thick film conductor, a thin film conductor having chromium or titanium or the like as a base conductor and a gold surface can be used.

Reference numeral 23 denotes a high-frequency transmission line 22 on the lower surface of the insulating base 21 for reinforcing the connection with the external electric circuit board.
In this example, the reinforcing pad 23 is formed by a high-frequency transmission line 22 formed in a longitudinal direction substantially at the center of the lower surface of the insulating base 21.
Are formed at positions at a distance d of 1.5 mm or more in the line width direction, and reinforcing pads 23 are formed at the four corners of the rectangular insulating base 21 respectively.

In this example, each reinforcing pad 23 is extended on the side surface of the insulating base 21 to form a side pattern 24. When the side patterns 24 are extended as described above, stress concentration can be dispersed, and a more effective reinforcing pad can be obtained. However, these side patterns 24 are not always required.

The reinforcing pad 23 and the side pattern
The position and size of 24 are 1.5 m from the high-frequency transmission line 22
The distance is set arbitrarily within a range that is not more than m apart and does not affect shorting of other patterns. In addition, the reinforcing pad 23 and the side pattern 24 can be made of a thick film or a material that can obtain sufficient adhesion strength with the ceramic of the insulating base 21 and whose surface is wetted by a brazing metal such as solder. A film of any material such as a thin film may be used.

Reference numeral 25 denotes an electrode pad for a power supply or a bias signal, and these are provided as necessary according to the specifications and characteristics of the high-frequency semiconductor element.

According to such a high-frequency surface-mount type wiring board of the present invention, the distance d in the width direction of the transmission line 22 formed on the lower surface of the insulating base 21 is 1.5 to 1.5 mm. mm or more away from the formation of the reinforcing pad 23 for reinforcing the joint with the external electric circuit board,
The end of the high-frequency transmission line 22 was joined to the wiring conductor on the surface of the external electric circuit board by a conductive connection member such as a solder bump, and the reinforcing pad 23 and the corresponding pad were provided on the external electric circuit board. The wiring board and the external electric circuit board are connected to the wiring board and the external electric circuit board without adversely affecting the high-frequency signal propagating through the high-frequency transmission line 22 by joining the wiring conductor and the connection pad with the conductive connection member such as a solder bump. The bonding area can be increased to increase the bonding strength, and as a result, the bonding reliability can be improved without adversely affecting the high frequency characteristics.

Then, the high-frequency semiconductor element is mounted on the mounting portion 21a of the insulating base 21, and its electrodes and the high-frequency transmission line 22 near the mounting portion 21a are electrically connected by bonding wires, solder bumps or the like. A lid is attached to the upper surface of the insulating base 21 so as to cover the mounting portion 21a, or the mounting portion 21a
By attaching a lid to the upper surface of the wall member joined to the upper surface of the insulating base 21 so as to surround the insulating substrate 21, or by applying a sealing resin so as to cover the mounting portion 21a, the high-frequency semiconductor element is airtight. To provide a high-frequency semiconductor device having excellent connection reliability and excellent high-frequency characteristics.

As a structure for leading the high-frequency transmission line 22 from the vicinity of the mounting portion 21a to the lower surface of the insulating base 21, as shown in a partially cutaway perspective view in FIG.
The first high-frequency transmission line 22a formed near the mounting portion 21a on the upper surface of the insulating base 21.
A second high-frequency transmission line 22b formed on the lower surface of the insulating base 21 so as to face the first high-frequency transmission line 22a; and a first high-frequency transmission line 22b formed inside the insulating base 21.
a and a ground conductor layer 26 in which a slot hole 27 is formed corresponding to a position where the second high-frequency transmission line 22b faces the first high-frequency transmission line 22b. By electromagnetically coupling the transmission line 22a and the second high-frequency transmission line 22b via the slot hole 27, there is no reflection loss or radiation loss in the hermetic seal portion, and
A second high-frequency surface-mount wiring board according to the present invention having extremely good high-frequency characteristics with low transmission loss without being affected by transmission loss due to through conductors.

By adopting such a structure for deriving the high-frequency transmission line, a high-frequency signal can be derived with low loss, and at the same time, the first high-frequency transmission line 22a is formed on the upper surface of the insulating base 21.
Need not enter the side wall of the insulating base 21,
When this wiring board is used as a package, the reliability of hermetic sealing inside can be made high.

Then, the high-frequency semiconductor element 28 is mounted on the mounting portion 21a of the insulating base 21, and the electrode on the upper surface thereof is connected to the first high-frequency transmission line 22a by the bonding wire 29.
Alternatively, the electrode on the lower surface thereof and the first high-frequency transmission line 22a are joined by a conductive connecting member such as a solder bump to form an insulating base.
By attaching a lid to the upper surface of the 21 to cover the mounting portion 21a, or by applying a sealing resin to cover the mounting portion 21a, the high-frequency semiconductor element 24 is housed in an airtight manner, A high-frequency semiconductor device having excellent connection reliability with an external electric circuit board and extremely high frequency characteristics is obtained.

[0038]

Next, a specific example of the high frequency surface mount type wiring board of the present invention will be described.

As a ceramic material for the insulating substrate, a 92% -purity alumina ceramic for a multilayer wiring board (coefficient of thermal expansion: 7 × 10 ⁻⁶ / ° C.) is used. A ceramic green sheet having a predetermined thickness of this alumina ceramic is prepared. The upper and lower surfaces of the green sheet and the through-holes formed therein are printed with a wiring conductor and a high-frequency transmission line constituting a predetermined mounting portion using a tungsten paste, and a pattern to be a through conductor is printed. It was cut into a rectangular shape having a size of about 9 mm and a width of about 6 mm, and fired in a humidified forming gas at 1600 ° C. for 1 hour. Thereafter, the high-frequency transmission line was plated with nickel at 1 μm and gold at 1.5 μm to obtain a high-frequency surface-mount type wiring board of the present invention and a sample of a comparative example.

Here, as a sample of the embodiment of the present invention, the pattern of the high-frequency transmission line and the reinforcing pad on the lower surface of the insulating base is shown in FIG.
For the high-frequency transmission line 22 of 2 mm, the distance d between the high-frequency transmission line 22 and the reinforcing pad 23 is 1.0 mm · 1.2 mm.
・ Samples A, B, C, and 1.5 mm and 2.0 mm respectively
D. As a sample of another embodiment of the present invention, a pattern of a high-frequency transmission line and a reinforcing pad is shown in FIG.
(A) As shown in the bottom view, it is assumed that a reinforcing pad 30 is formed between the high-frequency transmission lines 22 at the center of the lower surface of the insulating base 21 and the high-frequency transmission line 22 having a line width of 0.2 mm. And the distance d between the high-frequency transmission line 22 and the reinforcing pad 30
1.5 mm, the length L of the reinforcing pad 30 is 3 mm, and the width W
Was set to 4 mm to obtain a sample E. Further, as a sample of the comparative example, as shown in the bottom view in FIG.
A sample F having a conventional pattern in which no reinforcing pad was formed on the high-frequency transmission line 22 of 0.2 mm was used.

For each of the samples A to F thus obtained, an insulating substrate was used for the wiring conductor made of copper formed on the surface of the glass-fluorine resin composite copper-clad circuit board (coefficient of thermal expansion: 13 × 10 ⁻⁶ / ° C.). The end of the high-frequency transmission line 22 on the lower surface 21 was joined by soldering and surface-mounted. Here, the connection between the wiring conductor and the end of the high-frequency transmission line 22 by soldering is performed by printing a solder paste in a predetermined pattern on the wiring conductor, and placing the solder paste on the end of the high-frequency transmission line 22 on the lower surface of the sample. After mounting each sample so as to be positioned, the solder was melted in a reflow furnace. The amount of the solder paste was adjusted so that the solder height was 50 μm or less.

A temperature cycle test of -65 ° C. to + 150 ° C. was performed on 10 samples A to F each connected to the external electric circuit board. After the temperature cycle test, the occurrence of a connection failure was confirmed by examining whether or not the connection between the wiring conductor of the external electric circuit board and the high-frequency transmission line 22 of each sample was broken using a tester. The criterion for passing this test was that no connection failure such as disconnection of the connection portion occurred in 1000 cycles.

In this test, the number of occurrences of connection failures with respect to the number of temperature cycles was examined. In sample F of the comparative example, two were connected at 500 cycles, five were further at 1,000 cycles, and the remaining three were connected at 2,000 cycles. A defect has occurred. On the other hand, in Samples A to E, no connection failure occurred in 1000 cycles, and in Sample E, one in 2000 cycles,
One more connection failure occurred in 3000 cycles, and sample A
In each of D to D, only one connection failure occurred in 3000 cycles. From these results, it was confirmed that all of the samples A to E in which the reinforcing pads 23 or 30 were formed near the high-frequency transmission line 22 on the lower surface of the insulating base 21 had good connection reliability.

Next, for each of the samples A to E, a sample using the electromagnetic coupling structure shown in FIG. 2 was prepared as a lead-out structure from the vicinity of the mounting portion 21a to the high-frequency transmission line 22 on the lower surface of the insulating base 21. High-frequency signal transmission characteristics from the mounting portion 21a to the end of the high-frequency transmission line 22 were confirmed. In addition,
A microstrip line having a line width of 0.2 mm was used as the high-frequency transmission line 22 in the vicinity of the mounting portion 21a and on the lower surface of the insulating base 21.

As an evaluation of the transmission characteristics of the high-frequency signal, a coplanar / microstrip line conversion board is provided at the mounting portion of each sample and at the joint between the end of the high-frequency transmission line and the external electric circuit board. The insertion loss was measured at 40 GHz using a probe and a network analyzer. The acceptance criteria here were -1 dB or less.

As a result, for sample A, -4 dB,
-1.5 dB for sample B, -0.7 dB for sample C, sample D
In this case, -0.6 dB was obtained in Sample E, and -0.6 dB was obtained in Sample E. Samples C, D, and E, which are examples of the present invention, all had good transmission characteristics.

From the above results, according to the samples C, D and E of the present invention, a high-frequency surface-mounted wiring board having high connection reliability with an external electric circuit board and excellent high-frequency transmission characteristics can be obtained. Was confirmed.

It should be noted that the above is only an example of the embodiment of the present invention, and the present invention is not limited to the embodiment. Various modifications and improvements may be made without departing from the gist of the present invention. No problem. For example, the reinforcing pad may or may not be grounded, and in the case where a microstrip line is used as the high-frequency transmission line on the lower surface of the insulating base, a conversion board for coplanar line and a coplanar line is incorporated at the end thereof. A ground layer may be formed between the high-frequency transmission line and the reinforcing pad.

[0049]

As described above, according to the first high frequency surface mount type wiring board of the present invention, the high frequency transmission line joined to the wiring conductor of the external electric circuit board formed on the lower surface of the insulating base. Is formed at a distance of at least 1.5 mm from the external electric circuit board. This reinforcing pad and the corresponding connection pads provided on the external electric circuit board are provided. And the reinforcing pad and the high-frequency transmission line are not coupled at a high frequency, so that the wiring board and the external The bonding area with the circuit board can be increased to increase the bonding strength, and as a result, the bonding reliability can be improved without affecting the high frequency characteristics.

Further, according to the second high frequency surface mount type wiring board of the present invention, the high frequency transmission line led out from the mounting portion on the upper surface of the insulating base to the lower surface of the insulating base is placed on the upper surface of the insulating base near the mounting portion. And a second high-frequency transmission line formed on the lower surface of the insulating base so as to face the first high-frequency transmission line, and formed inside the insulating base. And a first high-frequency transmission line and a second high-frequency transmission line.
And a ground conductor layer in which a slot hole is formed corresponding to a position facing the high-frequency transmission line. The first high-frequency transmission line and the second high-frequency transmission line are interposed through the slot hole. Because of the electromagnetic coupling, the first high-frequency transmission line on the upper surface of the insulating base passes through the wall member or the side wall of the lid joined to the upper surface of the insulating base to hermetically seal the high-frequency semiconductor element. High-frequency transmission line can be connected to the second high-frequency transmission line on the lower surface of the insulating substrate without using a through-hole conductor or a via conductor provided inside the insulating substrate. There is no reflection loss or radiation loss at
The transmission loss from the first high-frequency transmission line on the upper surface of the insulating base to the second high-frequency transmission line on the lower surface is suppressed by eliminating the influence of the transmission loss due to the through conductor, and the transmission loss is reduced to 100 GH.
A high-frequency signal having a frequency up to about z can be transmitted satisfactorily, and the high-frequency characteristics can be further improved while increasing the bonding strength between the wiring board and the external electric circuit board.

As described above, according to the present invention, a high-reliability high-frequency semiconductor element housing package or a high-reliability high-frequency semiconductor element housing package having improved junction strength between a wiring board and an external electric circuit board without deteriorating high-frequency characteristics. A high-frequency surface-mounted wiring board suitable for a high-frequency semiconductor device can be provided.

[Brief description of the drawings]

1 (a) to 1 (c) are bottom views each showing an example of an embodiment of a high-frequency surface-mounted wiring board according to the present invention.
It is a horizontal sectional view and a vertical sectional view.

FIG. 2 is a partially cutaway perspective view showing an example of an embodiment of a second high-frequency surface mount type wiring board according to the present invention.

FIG. 3 (a) is a bottom view showing an example of a high-frequency surface mount type wiring board of the present invention, and FIG. 3 (b) is a bottom view showing a comparative example.

FIG. 4 is a partially cutaway perspective view showing an example of a conventional high-frequency semiconductor device.

FIG. 5 is a partially cutaway perspective view showing a structure for leading out a high-frequency transmission line in a high-frequency surface-mount wiring board.

[Explanation of symbols]

 21... Insulating base 21a... Mounting part 22... High-frequency transmission line 22a... First high-frequency transmission line 22b. , 30 ... Reinforcement pad 26 ... Ground conductor layer 27 ... Slot hole 28 ... High frequency semiconductor element

Claims (2)

[Claims] 1. A mounting portion on which a high-frequency semiconductor element is mounted is formed on an upper surface or a lower surface of an insulating base made of ceramics, and a high-frequency transmission line extending from the vicinity of the mounting portion to the lower surface of the insulating base is formed. A high-frequency surface-mounted wiring board in which an end of the high-frequency transmission line is joined to a wiring conductor on the surface of the external electric circuit board via a conductive connection member; A reinforcing pad for reinforcing bonding with the external electric circuit board at a position separated from the transmission line by 1.5 mm or more. A second high-frequency transmission line formed on an upper surface of the insulating substrate; and a lower surface of the insulating substrate, wherein the high-frequency line conductor is formed on an upper surface of the insulating substrate. A second high-frequency transmission line formed opposite to the first high-frequency transmission line, and the first high-frequency transmission line and the second high-frequency transmission formed inside the insulating base. The first high-frequency transmission line and the second high-frequency transmission line are electromagnetically coupled to each other through the slot hole. 2. The high frequency surface mount type wiring board according to claim 1, wherein