阅读说明：本技术 集成ipd技术封装的滤波器及封装方法 (Filter packaged by integrated IPD technology and packaging method ) 是由 高安明 姜伟 于 2021-01-15 设计创作，主要内容包括：本发明提供了一种集成IPD技术封装的滤波器及封装方法,包括：体声波谐振器区域、盖板区域；所述体声波谐振器区域设置于集成IPD技术封装的滤波器的上半部分；所述盖板区域设置于下半部分；所述盖板区域包括：集总元件；该滤波器可以在完成自身封装的同时实现设定的滤波性能。所述体声波谐振器区域包括：硅衬底、体声波谐振器；所述体声波谐振器设置于硅衬底上。本发明针对所提出的新型滤波器设计了一套合理的加工流程,可以降低工艺复杂度,提高产品的稳定性。(The invention provides a filter and a packaging method for integrated IPD technology packaging, which comprises the following steps: a bulk acoustic wave resonator region, a cover plate region; the bulk acoustic wave resonator region is arranged on the upper half part of the filter packaged by the integrated IPD technology; the cover plate area is arranged on the lower half part; the cover plate region includes: a lumped element; the filter can achieve set filtering performance while completing self-packaging. The bulk acoustic wave resonator region includes: a silicon substrate, a bulk acoustic wave resonator; the bulk acoustic wave resonator is arranged on the silicon substrate. The invention designs a set of reasonable processing flow aiming at the novel filter, which can reduce the process complexity and improve the stability of the product.)

1. An integrated IPD technology packaged filter, comprising: a bulk acoustic wave resonator region, a cover plate region;

the bulk acoustic wave resonator region is arranged on the upper half part of the filter packaged by the integrated IPD technology;

the cover plate area is arranged on the lower half part;

the cover plate region includes: a lumped element;

the bulk acoustic wave resonator region includes: a silicon substrate, a bulk acoustic wave resonator;

the bulk acoustic wave resonator is arranged on the silicon substrate.

2. The integrated IPD technology packaged filter according to claim 1, wherein the bulk acoustic wave resonator adopts any one or more of the following structures:

-silicon back side etch structures;

-a void structure;

-a bragg reflector structure.

3. The integrated IPD technology packaged filter according to claim 1, wherein the lumped elements are lumped elements processed using IPD technology.

4. The integrated IPD technology packaged filter according to claim 3, wherein said lumped element comprises: a capacitor and an inductor;

the lumped elements are integrated in the silicon oxide layer on the surface of the silicon substrate by IPD technology.

5. The integrated IPD technology packaged filter according to claim 1, wherein the bulk acoustic wave resonator region and the cover plate region are connected by copper pillars.

6. The integrated IPD technology packaged filter of claim 1, wherein said cover plate area comprises: an IPD cover plate;

the IPD cover plate can be bonded with a chip where the bulk acoustic wave resonator is located.

7. The integrated IPD technology packaged filter of claim 1, wherein the input end of the bulk acoustic wave resonator region and the output end of the bulk acoustic wave resonator region extend through two metal vias to the upper surface of the IPD cover plate.

8. The integrated IPD technology packaged filter according to claim 1, further comprising: a metal pad;

the metal pad is arranged on the surface of the IPD cover plate.

9. The integrated IPD technology packaged filter according to claim 8, further comprising: a metal pad;

and a layer of tin is arranged on the surface of the metal bonding pad.

10. A method for packaging a filter packaged by an integrated IPD technology, wherein the filter packaged by the integrated IPD technology is packaged by using the filter packaged by the integrated IPD technology of any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of filters, in particular to a filter packaged by an integrated IPD (IPD) technology and a packaging method.

Background

With the rapid development of 5G communication technology, the market demand for miniaturized, high-performance filters is increasing. Patent document CN201210345115.5 discloses a structure in which a piezoelectric acoustic wave filter and a chip package are combined, which proposes to introduce mutual inductance between inductors connecting the piezoelectric acoustic wave filter, adjust the position of the transmission zero point of the piezoelectric acoustic wave filter, and improve the high-frequency performance of the filter.

The defects of the prior art are as follows: the lumped elements used by the conventional filter are usually realized by surface-mounted components, each inductor and each capacitor occupy a large space, and the lumped elements used by the filter provided by the patent are realized by an IPD (integrated delay device) technology, so that the size of the whole filter is greatly reduced; the filter provided by the patent integrates the required lumped elements on a packaging cover plate of the bulk acoustic wave resonator by utilizing the IPD technology, and the resonator and the lumped elements are connected through copper columns, so that the filter can achieve set performance while realizing good packaging; the IPD element and the resonator required by the conventional hybrid filter based on the IPD lumped element and the bulk acoustic wave resonator are usually packaged separately and then interconnected, and the conventional packaging process may have the problems of poor stability, high processing complexity and the like.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a filter packaged by an integrated IPD technology and a packaging method.

The invention provides a filter packaged by an integrated IPD technology, which comprises: a bulk acoustic wave resonator region, a cover plate region; the bulk acoustic wave resonator region is arranged on the upper half part of the filter packaged by the integrated IPD technology; the cover plate area is arranged on the lower half part; the cover plate region includes: a lumped element; the filter can achieve set filtering performance while completing self-packaging. The bulk acoustic wave resonator region includes: a silicon substrate, a bulk acoustic wave resonator; the bulk acoustic wave resonator is arranged on the silicon substrate.

Preferably, the bulk acoustic wave resonator adopts any one or more of the following structures:

-silicon back side etch structures;

-a void structure;

-a bragg reflective layer structure;

preferably, the lumped elements are lumped elements processed by IPD technology.

Preferably, the lumped element comprises: a capacitor and an inductor;

the lumped element is integrated in the silicon oxide layer on the surface of the silicon substrate through an IPD technology;

preferably, the bulk acoustic wave resonator region and the cover plate region are connected through a copper pillar.

Preferably, the cover plate region includes: an IPD cover plate;

the IPD cover plate can be bonded with a chip where the bulk acoustic wave resonator is located.

Preferably, the input end of the bulk acoustic wave resonator region and the output end of the bulk acoustic wave resonator region extend to the upper surface of the IPD cover plate through two metal vias.

Preferably, the method further comprises the following steps: a metal pad;

the metal pad is arranged on the surface of the IPD cover plate.

Preferably, the method further comprises the following steps: a metal pad;

the surface of the metal pad is provided with a layer of tin to aid in soldering the filter into a particular circuit.

According to the method for packaging the filter packaged by the integrated IPD technology, the filter packaged by the integrated IPD technology is packaged by adopting the filter packaged by the integrated IPD technology.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention designs a set of reasonable processing flow aiming at the novel filter, which can reduce the process complexity and improve the stability of the product;

2. the packaging technology adopted in the filter provided by the invention enables the chip where the IPD element is positioned and the chip where the bulk acoustic wave resonator is positioned to be mutually cover plates and to be interconnected internally, so that the overall processing cost of the filter is greatly reduced;

3. by adopting the IPD technology, the problem that the conventional lumped component occupies a large space is solved, and the IPD technology can be compatible with a standard photoetching process, so that the design and processing complexity of the whole filter is greatly reduced;

4. the required lumped elements are integrated on the packaged cover plate, so that the problem that the conventional filter needs an additional area for designing and placing the lumped elements is solved, the space required by the whole filter is greatly reduced, and the filter provided by the patent can obtain set filtering performance while realizing good packaging;

5. by packaging the IPD lumped element and the bulk acoustic wave resonator together, the problem that the IPD lumped element and the resonator need to be independently packaged in a conventional hybrid filter based on the IPD lumped element and the bulk acoustic wave resonator is solved. The filter packaging technology provided by the patent can enable the chip where the IPD element is located and the chip where the bulk acoustic wave resonator is located to be mutually cover plates and be interconnected inside, so that the overall processing cost of the filter is greatly reduced.

6. By adopting the packaging process flow provided by the patent, the problems of high complexity and poor stability of the conventional packaging process are solved. The packaging process flow provided by the patent can effectively realize product packaging, and ensures that lumped elements on the packaging cover plate can accurately contact with the welding spots of the specific piezoelectric resonator, thereby helping the filter to realize good filtering performance.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

fig. 1 is a schematic view of the overall structure of the present invention.

FIG. 2 is a schematic view of a first process flow in an embodiment of the present invention.

Fig. 3 is a schematic diagram illustrating a realization principle of a bulk acoustic wave filter of the integrated IPD technology according to the present invention.

FIG. 4 is a second process flow diagram in an embodiment of the invention.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

Integrated Passive Devices (IPD) technology can integrate discrete Passive Devices within a substrate, improving device Q and system integration. As shown in fig. 1, this patent proposes an acoustic wave filter integrating IPD technology. The filter is mainly divided into two parts, wherein the upper half part is a bulk acoustic wave resonator area, and the lower half part is a packaged cover plate area. The filter has the advantages that the lumped elements processed by the IPD technology exist in the cover plate area, the upper part and the lower part are connected through the copper columns at specific positions, and the filter can achieve set filtering performance while completing self packaging. The bulk acoustic resonator region of the upper half comprises a silicon substrate 1 and a bulk acoustic resonator 2 implemented on the silicon substrate. The bulk acoustic wave resonator has three main structural types: the bulk acoustic wave resonator in the patent can be selected from any one or a plurality of structures according to specific design requirements to be combined. In addition, the number and topology of the resonators may be specifically designed to achieve the desired performance. Through a specific photolithography process, a bulk acoustic wave resonator array can be realized on a silicon substrate 1, and a resonator pad 3 is reserved, the surface material of which is gold in most cases.

To further optimize the performance of the filter, it is often necessary to incorporate specific lumped elements in the resonator topology. Such as connecting inductors in series on the resonator branches to shift the resonance frequency or designing specific matching networks to increase the bandwidth of the filter, improve out-of-band rejection, etc. In this patent, these lumped elements (capacitors 9, inductors 10) can be integrated in the silicon oxide 8 layer on the surface of the silicon substrate 1 by IPD technology, and specific pads are reserved to facilitate the connection to the resonator. After the bulk acoustic wave resonator portion and the cover portion containing the lumped elements are separately fabricated, the IPD cover can be fabricated by the packaging technique shown in fig. 2, and then bonded to the chip on which the bulk acoustic wave resonator is located. Wherein, the lumped elements on the cover plate and the specific resonator can be connected through the copper pillar according to the design requirement. In addition, the input and output of the packaged filter extend through two metal vias to the lower surface of the cover plate, leaving metal pads, the surface of which has a layer of tin 4 to help solder the filter into the specific circuit.

As shown in fig. 2, the packaging technology provided by this patent includes the following processes: 1. sputtering a thin titanium layer 6 on the cover plate shown in fig. 2a, to which the IPD element has been integrated, and then growing a thin copper layer 5; 2. coating a certain thickness of photoresist A11, exposing, and developing to obtain a specific shape shown in FIG. 2 b; 3. growing a thicker layer of copper as shown in figure 2c using an electroplating technique; 4. polishing the upper surface of the obtained sample to obtain a uniform plane with a specific thickness in fig. 2 d; 5. electroplating a layer of tin 4 on the surface of the copper layer exposed in fig. 2 e; 6. removing the photoresist layer to obtain the shape shown in fig. 2 f; 7. the titanium layer 6 and the copper layer 5 sputtered in step 1 are etched to finally obtain the copper pillar shown in fig. 2e, which has a layer of tin 4 on top and a layer of titanium 6 on the bottom. In addition, the middle copper column is responsible for connecting the resonator and the IPD technology integrated component, and two sides are actually a circle of packaging copper rings (Seal rings) for supporting and sealing. 8. And (3) butt-bonding the cover plate in the figure 2e and the substrate with the resonator to obtain the final bulk acoustic wave filter with the package.

Considering process complexity and cost, the bulk acoustic wave filter of the integrated IPD technology proposed by this patent can also be implemented by the manner shown in fig. 3. The length of the connecting and supporting copper pillars in fig. 3 is greatly reduced compared to the structure shown in fig. 1, which makes the packaged device more robust. In addition, in order to prevent the resonator from touching the cover plate during packaging, a groove with a certain size is etched in the cover plate corresponding to the resonator area. The design of the other regions is the same as the structure shown in fig. 1.

Similarly, the filter shown in fig. 3 can be implemented by the process flow shown in fig. 4: 1. coating a layer of photoresist B12 on the cover plate integrated with the IPD element, and exposing and developing to obtain a specific shape shown in FIG. 4 a; 2. dry etching the substrate obtained in fig. 4a, and then removing the photoresist B12 to obtain the groove shown in fig. 4B; 3. further coating a photoresist C13, and exposing and developing to obtain the shape shown in FIG. 4C; 4. sputtering a titanium layer 6, a copper layer 5 and a tin layer 4 with specific thicknesses on the substrate of fig. 4c in sequence by using a sputtering technique to obtain the cover plate with the connecting metal posts shown in fig. 4 d; 5. and butting the processed cover plate with a chip with a resonator to finally obtain the bulk acoustic wave filter with a package and integrated with the IPD technology.

Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, units provided by the present invention as pure computer readable program code, the system and its various devices, modules, units provided by the present invention can be fully implemented by logically programming method steps in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like. Therefore, the system and various devices, modules and units thereof provided by the invention can be regarded as a hardware component, and the devices, modules and units included in the system for realizing various functions can also be regarded as structures in the hardware component; means, modules, units for performing the various functions may also be regarded as structures within both software modules and hardware components for performing the method.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.