JP2002261581A - High frequency module components - Google Patents

Abstract

(57) [Summary] (Problem corrected) [PROBLEMS] In a high-frequency electronic circuit component including a ceramic multilayer substrate and a flip-chip mounted surface acoustic wave device (SAW) directly mounted thereon, airtightness of a plurality of SAW devices is collectively determined. A high frequency module component and a method of manufacturing the same that can improve productivity, improve reliability during use, improve mountability during mounting, and further reduce product size. provide. A surface acoustic wave device (SAW) is provided on a multilayer substrate (1).
And other surface mount elements Di and R are mounted, the surface acoustic wave element SAW is directly flip-chip mounted on an electrode provided with a metal film of the multilayer substrate 1, and a plurality of surface acoustic wave elements SAW A high-frequency module component having a configuration that is collectively covered with the sealing member 14 and hermetically sealed, and a method of manufacturing the same are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency module component having a ceramic multilayer substrate and a flip-chip surface acoustic wave device, which enhances the reliability in use and the mountability during mounting. The present invention relates to a module structure and a method for manufacturing the same, which can be reduced in size and height and can improve productivity.

[0002]

2. Description of the Related Art In the field of electronic equipment, there is always a market demand for miniaturization, and the size and weight of components used are also required. This tendency is remarkable in high-frequency devices typified by mobile phones, and particularly in parts used. In the high-frequency equipment, the density has been remarkably increased even in the mounting of components, and the demand for small size and light weight has been met.

On the other hand, in order to cope with such miniaturization, a multilayer substrate having a plurality of conductor layers is used instead of a single-layer substrate.

In a ceramic multilayer substrate, an insulating layer of the multilayer substrate is formed of an electrically insulating ceramic, and a conductor layer is formed of silver or the like. Such a ceramic multilayer substrate,
Compared to a general resin multilayer board, it has features such as less loss at high frequency, good heat conduction, good dimensional accuracy, and excellent reliability.

In the case of a ceramic multilayer substrate, since the internal conductors are formed in a coil shape or are opposed to each other in parallel, an inductance and a capacitance can be formed in each of them, and low loss and high dimensional accuracy can be obtained. , Q having a high tolerance and a small tolerance can be formed therein.

[0006] Such a feature is utilized in a high-frequency circuit such as a cellular phone, in particular, as a collective element having various characteristics mounted on its surface and having high characteristics and miniaturization, that is, a module.

On the other hand, a high-frequency module has a simpler device structure than a conventional method in which discrete components are mounted one by one to form a circuit in order to organize the circuit for each function. Therefore, it is possible to provide a product having excellent reliability and characteristics.

Further, in the conventional discrete component, the design becomes complicated because the function of each component is performed by combining the characteristics of each component. However, when the module is modularized, the characteristic specifications are determined for each module. In designing the equipment, the design can be structured, and the manufacturing period can be shortened and labor can be saved.

FIG. 8 shows that GS has the highest production volume worldwide.
1 shows a block diagram of an M dual-band mobile phone. In the figure, a transmission signal IQ is input to an IQ module 137. This IQ module 137 has an IFVC
An IF signal is input from O120 via a frequency divider DIV138 and a 90 ° shifter and modulated. The signal output from the IQ modulator 137 is input to the mixer 132 via the phase detector 133. 900 V is applied to the phase detector 133 via the low-pass filters 134 and 135.
CO and 1800 VCO 136 are connected. The mixer 132 also has a 900 VCO and 18 VCO.
00VCO 117 is connected.

The signal output from the mixer 132 is 90
The frequency is modulated to 0 MHz or 1800 MHz, and the power amplifier 129 and the
The signal is input to the diplexer 102 via a path including the coupler 125, the low-pass filter 104, and the T / R switch 103, or is input to the diplexer 102 via a path including the power amplifier 130, the coupler 126, the low-pass filter 124, and the T / R switch 123. The signal input to the diplexer 102 is transmitted from the antenna 101.

Similarly, a 900 MHz or 1800 MHz signal input from antenna 101 to diplexer 102 is transmitted to T / R switch 103 or T / R switch 12.
3, the bandpass filter 105 and the amplifier 10
6, input to the mixer 111 through the path of the balun transformer 107, or the band-pass filter 108 and the amplifier 10
9. The signal is input to the mixer 111 through the balun transformer 110. The mixer 111 has 900 VCO and 1
800VCO 117 is connected.

The IF-modulated signal output from the mixer 111 is input to a mixer 114 via a band-pass filter 112 and an amplifier 113. Mixer 114 contains I
The FVCO 120 is connected. The signal output from the mixer 114 is input to an IQ demodulator 116 via an automatic gain controller 115 and demodulated. In addition, IQ
The IF signal is input to the demodulator 116 from the IFVCO 120 via the frequency divider DIV138 and the 90 ° shifter, and is modulated. IFVCO 120, 900
Each of the VCO and the 1800 VCO 117 has an IF
The PLL 119 and the RF PLL 118 are connected.

The above-described modularization is performed by several functions, and for example, the antenna switch section 140 of such a circuit is actually mounted by mounting elements on a ceramic multilayer substrate.

FIG. 9 shows a configuration example of such a module. In the figure, a diode element D and a resistance element R are arranged on a substrate 1. The shield case 15 is arranged so as to cover them. Also, substrate 1
The conductor 10 is formed and arranged on the side and inside of the
A capacitor 12, an inductor 13, and the like are formed. These conductors 10 are vertically connected by via holes 11.

At present, modularization is realized by a single function such as a power amplifier and an antenna switch module. However, if a wider range of functions is modularized, the advantage of modularization is further brought out.

Of course, modularization with the addition of a SAW element is also important. Conventional SAW elements use so-called package components. In this case, it is possible to mount the packaged product and modularize it, but it is also possible to mount the element chip directly on the substrate. In this way, a small size and low profile can be realized, and further low cost can be realized.

The ceramic multilayer substrate has an inductance,
Capacitance can be built-in, which makes it possible to reduce the size, but on the other hand, it is difficult to reduce the height. For this reason, in a general module in which a package is further mounted on a substrate, it is not possible to sufficiently respond to a demand for a reduction in height in the future.

Further, a package product requires a larger occupied area than the original chip. Of the components used, SAW elements are one of the tallest and have a large occupation area. Under these circumstances, SAW
In some way, without using a package,
It is desired to mount it on a ceramic multilayer substrate.

On the other hand, in the production of a SAW element, there are a step of forming a chip and a step of mounting and sealing in a package, and the costs are substantially the same. what if,
If it can be mounted directly on a ceramic multilayer substrate, it can be manufactured at a low cost because it does not go through the steps of mounting and sealing in a package.

As described above, in the high-frequency module, it is desirable that the SAW element is directly mounted on a ceramic multilayer substrate on which other components are mounted by soldering as a chip.

However, the SAW element is sensitive to the atmosphere in the atmosphere, and if exposed, there is a problem in reliability. It is necessary to perform some kind of hermetic sealing. Therefore, if sealing is performed individually as in the prior art, the height is reduced as compared with the case using a package, but there is no significant difference in miniaturization.

Further, in such an electronic component, it is necessary that the electronic component can be transported by a suction nozzle in order to perform pick and place using a mounter.
Therefore, when the conventional packaged product is mounted, it is necessary to further add a case that covers almost the entire surface of the component, and the height is further increased.

Further, the structure must be created through a process that satisfies all of the SAW mounting method, the soldering component mounting method, and the sealing method.

[0024]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-frequency electronic circuit component including a ceramic multilayer substrate and a flip-chip surface acoustic wave device (SAW) directly mounted on the ceramic multilayer substrate. A high-frequency module component which can be obtained in a lump, improve productivity, enhance reliability during use, improve mountability during mounting, and reduce product dimensions, and manufacture thereof Is to provide a way.

[0025]

That is, the above object is achieved by the following constitution of the present invention. (1) A surface acoustic wave device and another surface-mounted device are mounted on a multilayer substrate, and the surface acoustic wave device is directly mounted on a metal substrate electrode of the multilayer substrate by flip-chip mounting, and a plurality of surface acoustic wave devices are mounted. A high-frequency module component in which an elastic wave element is collectively covered with one sealing member and hermetically sealed. (2) The sealing member covering the surface acoustic wave element is disposed substantially at the center of the high-frequency module component (1).
High frequency module parts. (3) The above (1) or (2), wherein the surface acoustic wave element is separated from other solder mounting parts by a sealing member.
High frequency module parts. (4) At least one of the surface mount elements other than the surface acoustic wave element is mounted on the multilayer substrate by soldering, and an area of a portion covered by the sealing member is 20%.
A high-frequency module component having a sealing member having a flat area of 1 mm ² or more, and 50% or less. (5) A high-frequency module component in which a sealing member covering the surface acoustic wave element is adhered to a multilayer substrate with an adhesive, and a conductor pattern inside the member is guided to the lower part by a through hole so as not to touch the adhesive flange. (6) A metal plating is applied to at least the component bonding portion of the conductor surface of the component mounting ceramic multilayer substrate, at least one device other than the surface acoustic wave device is mounted by soldering, and after cleaning, the surface acoustic wave device is metalized. A method for manufacturing a high-frequency module component, comprising the steps of: mounting a flip chip on a multilayer substrate by bonding them together; and bonding a sealing member of a surface acoustic wave element.

[0026]

In order to achieve the above object, the present inventors have attempted to improve the following points. (1) A plurality of SAW elements are collectively hermetically sealed in order to realize miniaturization. (2) In order to realize a low-profile structure, a case that covers the entire surface is eliminated, and suction is performed by another member. (3) Make both the soldering process and the SAW device mounting process compatible.

As a result, the high-frequency module component is mounted on the ceramic multilayer substrate by the gold ball bonding method, and the other surface-mounted components are mounted by soldering.
A plurality of SAW elements mounted in this manner are collectively structured to secure airtightness with a lid.

By directly mounting the SAW element in this way, the base plate of the SAW package product, which was conventionally required, is not required, and the height can be reduced. Further, by arranging the hermetically sealed portion substantially at the center of the module, it was possible to easily suck and arrange components. As a result, an extra canopy structure which has been conventionally required can be omitted, and a further reduction in size and height has become possible.

Incidentally, JP-A-6-97315 discloses that
There is disclosed an example in which another circuit component is mounted on a SAW element and sealed. In this publication, a SAW element is fixed face up on a resin substrate, and electrical connection is established by wire bonding.
It is clearly different from the one with SAW flip chip.

The high-frequency module component of the present invention can be further miniaturized by mounting a flip chip. The flip chip mounting method itself is known as disclosed in, for example, JP-A-10-270975. However, the difference is that the effect of the difference in the coefficient of thermal expansion from the substrate can be reduced by taking the form of a flip chip. Further, at first glance, it appears to disclose the mixed mounting with other passive components, but does not disclose the mixed mounting with the solder mounting component as in the present invention. In particular, solder is used for sealing, but in this case, an instantaneous heating method is used to avoid contamination by flux. In other words, this suggests that it is extremely difficult to mix with the mounted components. According to the present invention, it is also possible to mix and mount other solder components by performing the cleaning process, and thus, it becomes possible to mix and load simple and versatile components.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-frequency module component according to the present invention has a surface acoustic wave element (or Rayleigh wave, hereinafter sometimes referred to as SAW: Surface Acoustic Wave) and other surface-mounted elements mounted on a multilayer substrate. The surface acoustic wave device is directly flip-chip mounted on an electrode provided with a metal film of a ceramic multilayer substrate, and a plurality of SAW devices are collectively covered by one sealing member and hermetically sealed. is there.

As described above, a plurality of SAW elements are collectively covered with one sealing member and hermetically sealed, thereby realizing a reduction in size and height.

When a plurality of SAW elements are collectively sealed, the structure of the sealing member, that is, the lid, is the largest among the mounted components. For this reason, by disposing the sealing member at the approximate center of the module, that part can be sucked and handled, that is, picked and placed.

In the pick-and-place method, a suction pad is usually used. However, by arranging the sealing member substantially at the center of the module, the position of the center of gravity can be almost sucked, and the suction member having a nozzle shape can be stably used. And can be handled. Thereby, further miniaturization becomes possible. In other words, the canopy structure conventionally required for handling by pick and place can be eliminated, and the size and height can be reduced accordingly.

Further, since the elastic wave element is isolated from other mounted components by the sealing member, the airtightness is maintained, and the elastic wave element can be effectively protected from moisture and gas.

The sealing member that covers the surface acoustic wave element is fixed to the multilayer substrate. However, considering the sealing effect, it is preferable that the sealing member is bonded with an adhesive. As such an adhesive, an adhesive for fixing and sealing used in a usual electronic component can be used, but an adhesive having a small influence on a SAW element due to outgassing during curing is preferable. Specific examples include an epoxy adhesive.

Preferably, the conductor pattern inside the sealing member is guided to the lower portion by a through hole so as not to touch the bonding portion of the sealing member, that is, the bonding flange portion, and is externally formed by the pattern of the intermediate layer of the multilayer wiring board. Should be derived. In this way, by preventing the conductor pattern inside the sealing member from touching the bonding portion of the sealing member, that is, the bonding flange portion, the adverse effect between the adhesive and the conductor is prevented.
For example, dielectric loss and wraparound of volatile components can be prevented.

Furthermore, since at least one of the surface mount elements other than the surface acoustic wave element is mounted on the multilayer substrate by soldering, the parts which have been mounted by the conventional soldering process are mounted in the same process. This makes it possible to effectively use parts and equipment and suppress an increase in cost.

The area of the portion covered by the sealing member is preferably 20% of the entire module surface.
% To 50%, especially 30% to 45%. Further, the area of the flat portion of the sealing member is preferably 1 mm ² or more, more preferably 2 mm ² or more in consideration of handling properties and the like, and the upper limit is a value determined in the above range.

The height of the sealing member may be any height that does not make contact with the surface acoustic wave element, and may be determined depending on the surface acoustic wave element and its mounting structure. Specifically, the gap with the surface acoustic wave element is 50 to
It may be 200 μm, especially about 70 to 120 μm.

The material used for the sealing member is not particularly limited as long as it can maintain predetermined airtightness and has strength enough to withstand handling. However, it is preferable to use a material having the same coefficient of thermal expansion as that of the substrate, and a similar material may be used. Specifically, ceramics, epoxy-based plastics, BT resin plastics and the like can be mentioned, and among these, ceramics are particularly preferable.

The multilayer substrate may be a resin substrate or a ceramic substrate as long as the multilayer substrate satisfies predetermined sizes and electrical characteristics, but a ceramic substrate is preferable. Examples of the ceramic substrate include a low-temperature fired substrate containing glass-alumina as a main component.

The number of layers of the multilayer substrate may be adjusted to the number of layers required according to the circuit configuration of the high-frequency module component, the mounted components, and the like. Usually, it is about 5 to 30 layers.

It is preferable to apply metal plating to the metal electrodes of the multilayer substrate. By applying the metal plating, the solder wettability of the electrode can be improved. Such metal plating includes Ni-Sn, Ni-solder, Ni-
Au and the like can be mentioned, and Ni-Au and the like similar to the GGI part are preferable.

The built-in SAW element may be of any form, and an appropriate SAW may be used depending on the function required for the module component.

The SAW element is directly flip-chip mounted on an electrode on a substrate by metal-metal bonding. In this case, the preferred metal for the inter-metal bonding of the flip chip is A
Examples thereof include u and Al, and Au is particularly preferable.

The high-frequency module component of the present invention may be manufactured according to the following steps. That is, metal plating is applied to at least the component bonding portion of the conductor surface of the component mounting ceramic multilayer substrate, at least one element other than the surface acoustic wave element is mounted by soldering, and after cleaning, the surface acoustic wave element is attached to the metal. Is mounted on the multilayer substrate by bonding, and the sealing member of the surface acoustic wave element is bonded.

By manufacturing in this way, components to be mounted by soldering can follow the conventional mounting method. Further, the surface of metal plating such as gold plating is rich in solder wettability and can be sufficiently fixed. However, the surface of the board after mounting the soldered components is contaminated by scattering of flux, solder residue, and the like, and mounting of the SAW mounting portion on a metal surface such as gold is in doubt.

For this reason, after components other than the SAW element are mounted, cleaning is performed to activate the metal surface so as not to hinder the mounting.

The cleaning can be activated to a level that does not hinder the mounting by conventional chemical cleaning, but it is more preferable to perform cleaning by plasma etching. In this case, it is necessary to set a condition that does not damage other mounted components. Further, in the bonding of the resin, the dirt and the attached matter around the SAW can be further removed by bonding in a vacuum.

[0051]

The present invention will be described in more detail with reference to the following examples.

A module component having a structure as shown in FIGS. 1 and 2 was manufactured. Here, FIG. 1 is a schematic sectional view of the module component, and FIG. 2 is a plan view. FIG. 3 shows a circuit diagram thereof. 1 and 2, a diode element D
i, a resistance element R is arranged, and two surface acoustic wave elements SAW are arranged near the center thereof. Further, a sealing member 14 is arranged so as to surround the two surface acoustic wave elements SAW. Inside the substrate 1, a conductor 10 for forming a circuit as shown in the circuit diagram of FIG. 3, an inductor, a capacitor, and the like are formed.

As the ceramic multilayer substrate, an alumina glass composite ceramic having an insulating layer and having 15 inner conductor layers was used. The external shape was about 6 mm, 4 mm and the thickness was 0.8 mm. The part of this circuit excluding the surface acoustic wave device has already been commercialized as a module. Its size is also about 6 mm and 4 mm.

From this example, it can be sufficiently understood that two SAW elements can be mounted on a device having the same size as that of the related art, and that the size can also be reduced. The height of the prototype module is 1.5 mm, which is approximately 2 mm when the SAW package is simply mounted on the conventional product. This also indicates that the height can be sufficiently reduced.

The surface conductor layer of the ceramic multilayer substrate was formed of a sintered silver conductor, which was plated with nickel to a thickness of about 2 to 3 μm, and further provided with a gold film having a thickness of 0.5 μm.

A solder paste was applied to the solder joint of the substrate, and each component of inductance, capacitance, and diode was mounted. Thereafter, the mixture was passed through a reflow furnace to fix the solder. Further, this sample was subjected to no cleaning, alkaline chemical cleaning, and plasma cleaning.

On the other hand, the gold stud bump was formed on the SAW chip through the same process as that of the package product. The size of each chip was a rectangle of 1.3 mm × 0.8 mm, which was used for GSM and DCS, respectively.

The SAW sample is placed on the terminal 23 of the substrate via the solder ball 22 with the S
It was arranged so that the bump 21 of the AW sample was located. Then, the ultrasonic wave from the SAW side and 600g
Was applied while applying a load of 2 to join the gold bumps to the gold surface of the substrate. This state is shown in FIG.

Thereafter, as shown in FIG. 1, the SAW element was covered with ceramic lids of different sizes so as to include the child. The weight at this time was about 0.15 g.
For comparison, an example using a conventional package is shown in FIG.
Shown in

The size of the lid part should be at least 1.6 × 1.
A thickness of 3 mm is sufficient, but a side wall of the lid, a margin with the element, and an adhesive portion are required. It is sufficient that the side wall portion is approximately 0.2 mm or more, and the margin is 0.05 mm or more. In this case, bonding can be performed sufficiently stably. Therefore, if it is 2.1 × 1.8 mm, it can function sufficiently as a sealing member. However, when this is actually set on the mounter and sucked up by the suction nozzle,
2.4 × 2mm for stable mounting of the mounter
This is a case where the lid is used. If the lid is larger than this, stable handling can be achieved.

However, considering the mounting of other components, the size of the lid was limited to 4 × 3 mm. In such pick and place, the condition range is considered to be determined by the weight, balance, and suction force. However, in the case of small ones, the size of the mounted parts is limited, and 4 × 3 mm is considered to be the limit.

In this case, under conditions that can be held stably,
The module needs approximately 20 to 20
It can be considered as 50% size.

Although the upper part of the lid is generally considered to be flat, this is not always the case, and the limit of suction by the nozzle was approximately 1 mm ² . Therefore, the flat portion needs an area of 1 mm ² or more.

As described above, the lid is for spatial isolation from other elements, and must be hermetically sealed to eliminate the influence of moisture in the atmosphere. is there.

At this time, as shown in FIG. 6, the surface conductor is a metal conductor, for example, gold is exposed, and the gold portion is bonded to the lid using an adhesive. Gold has poor adhesiveness, and is easily peeled off at the conductor electrode interface in contact with gold, and it is difficult to firmly bond anyway.

Therefore, when a multilayer substrate is used, the electrodes of the SAW mounting portion can be guided to the inside of the substrate by using through holes, and can be exposed to the outside of the lid. By doing so, the lid can be bonded only to the substrate material, for example, the ceramic portion, and a stable bonding strength can be obtained. FIG. 7 shows such a state.

However, in the case where the wire is connected to the lower layer through a through hole and further pulled up, the wire itself has inductance. When connecting with through holes, there was no particular problem up to a through hole length of 300 μm, but at 350 μm or more, an increase in inductance and a further increase in pure resistance were observed. Restricted.

In the case of bonding via a gold conductor portion, 100 pieces each having only the ceramic portion bonded are prepared, and 8
As a result of conducting a 5 ° C. 85% test and examining the characteristic deterioration, in the former case, 12 characteristic deteriorations were observed. In the latter, none was degraded. The property deterioration is presumed to be the result of airtightness being broken at the bonded portion and the entry of water vapor therefrom.

[0069]

As described above, in the present application, in a high-frequency electronic circuit component including a ceramic multilayer substrate and a flip-chip mounted surface acoustic wave device (SAW) directly mounted thereon, the airtightness of a plurality of SAW devices is improved. A high-frequency module component that can be obtained in a lump, improve productivity, increase reliability during use, improve mountability during mounting, and reduce product dimensions. A manufacturing method can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration example of a high-frequency module component of the present invention.

FIG. 2 is a schematic plan view showing a configuration example of a high-frequency module component of the present invention.

FIG. 3 is a circuit diagram showing a configuration example of a high-frequency module component of the present invention.

FIG. 4 is a schematic sectional view showing a mounting state of the surface acoustic wave device.

FIG. 5 is a schematic sectional view showing a configuration example of a conventional high-frequency module component.

FIG. 6 is a partial cross-sectional view showing a positional relationship between a sealing member and a conductor.

FIG. 7 is a partial cross-sectional view showing a positional relationship between a sealing member and a conductor.

FIG. 8 is a block diagram illustrating a configuration of a GSM dual-band mobile phone.

FIG. 9 is a cross-sectional view illustrating a configuration example of a modularized antenna switch unit.

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Substrate 10 Conductor 11 Via hole 12 Capacitor 13 Inductor 14 Sealing member 15 Sealing member D1 Diode element R Resistance element SAW Surface acoustic wave element

Claims (6)

[Claims] 1. A surface acoustic wave device and another surface mount device are mounted on a multilayer substrate, and the surface acoustic wave device is directly flip-chip mounted on a metal film-coated electrode of the multilayer substrate. A high-frequency module component in which the surface acoustic wave elements are collectively covered with one sealing member and hermetically sealed. 2. A sealing member covering the surface acoustic wave element,
2. The high-frequency module component according to claim 1, wherein the high-frequency module component is disposed substantially at the center of the high-frequency module component. 3. The device according to claim 1, wherein the surface acoustic wave element is separated from another solder mounting component by a sealing member.
High frequency module parts. 4. At least one of the surface mount elements other than the surface acoustic wave element is mounted on the multilayer substrate by soldering, and an area of a portion covered by the sealing member is 20%.
A high-frequency module component having a sealing member having a flat area of 1 mm ² or more, and 50% or less. 5. A high-frequency module in which a sealing member covering the surface acoustic wave element is adhered to a multilayer substrate with an adhesive, and a conductor pattern inside the member is guided to a lower portion by a through hole so as not to touch an adhesive flange. parts. 6. A surface acoustic wave device after applying metal plating to at least a component bonding portion of a conductor surface of a component mounting ceramic multilayer substrate, mounting at least one device other than a surface acoustic wave device by soldering, and performing cleaning. A method for manufacturing a high-frequency module component, comprising: mounting a flip chip on a multilayer substrate by bonding metals to each other, and bonding a sealing member of the surface acoustic wave element.