Manufacturing method for surface acoustic wave filter package structure

Abstract

A surface acoustic wave (SAW) filter package structure includes a dielectric substrate having a dielectric layer, a first patterned conductive layer, a second patterned conductive layer, and a conductive connection layer. The conductive connection layer is electrically connected between the first patterned conductive layer and the second patterned conductive layer, which are disposed at opposite sides of the dielectric layer. The second patterned conductive layer has a finger electrode portion. An active surface of a chip is faced toward the finger electrode portion. A polymer sealing frame is disposed between the chip and the dielectric substrate and surrounds the periphery of the chip to form a chamber together with the chip and the dielectric substrate. The mold sealing layer is disposed on the dielectric substrate and covers the chip and the polymer sealing frame. A manufacturing method of the SAW filter package structure is also disclosed.

Claims

1. A manufacturing method for surface acoustic wave filter package structure, comprising: forming a dielectric substrate with a first side and a second side on a carrier board, wherein the dielectric substrate has a first patterned conductive layer, a dielectric layer, a conductive connection layer, and a second patterned conductive layer; forming a plurality of polymer sealing frames on the second side of the dielectric substrate, wherein each of the polymer sealing frames has an opening to partially expose out of the dielectric substrate; arranging a plurality of the chips onto corresponding polymer sealing frames, wherein, an active surface of each of the plurality of the chips faces toward the second side of the dielectric substrate, and corresponds to the respective opening of the polymer sealing frame to form a closed cavity by the corresponding polymer sealing frame, the chip and the dielectric substrate; forming a mold sealing layer to cover the plurality of chips and the plurality of polymer sealing frames, and a side of the plurality of polymer sealing frames is exposed out of the mold sealing layer; and removing the carrier board.

2. The manufacturing method of claim 1, wherein the step of forming the dielectric substrate, comprising: arranging the first patterned conductive layer on one surface of the carrier board; arranging the dielectric layer on the carrier board to cover the first patterned conductive layer; forming a plurality of openings on the dielectric layer to partially expose the first patterned conductive layer; and arranging the second patterned conductive layer on the dielectric layer and the conductive connection layer, and the second patterned conductive layer at least has a conductive circuit portion, a conductive electrode portion and a finger electrode portion.

3. The manufacturing method of claim 2, wherein after arranging the second patterned conductive layer, further comprising: arranging another dielectric layer on the dielectric substrate and the second patterned conductive layer, and exposure out of one surface of the second patterned conductive layer.

4. The manufacturing method of claim 1, wherein after removal of the carrier board, further comprising: arranging a patterned protective layer on the first side of the dielectric substrate and partial exposure out of the first patterned conductive layer.

5. The manufacturing method of claim 1, wherein before or after the removal of the carrier board, further comprising: cutting according to an area of the plurality of chips and the plurality of polymer sealing frames to form a plurality of single package structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The parts in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of at least one embodiment. In the drawings, like reference numerals designate corresponding parts throughout the various diagrams, and all the diagrams are schematic.

(2) FIG. 1 is a schematic sectional view illustrating a conventional SAW filter package structure.

(3) FIG. 2 is a schematic sectional view illustrating a SAW filter package structure according to the preferred embodiment of the present invention.

(4) FIG. 3A through FIG. 3J are schematic diagrams illustrating a method of making a SAW filter package structure according to the preferred embodiment of the present invention.

(5) FIG. 4 is an over-look view illustrating the SAW filter package structure.

(6) FIG. 5 is a schematic diagram illustrating a method of making a SAW filter package structure according to another preferred embodiment, wherein the alignment of the surface of the second patterned conductive layer with the surface of the dielectric layer at the second side of the dielectric substrate.

(7) FIG. 6 is a schematic sectional view illustrating a SAW filter package structure according to another preferred embodiment of the present invention.

(8) FIG. 7 is a schematic diagram illustrating a method of making a SAW filter package structure according to furthermore preferred embodiment, wherein the side of the polymer sealing frame is clad in the mold sealing layer.

(9) FIG. 8 is a schematic sectional view illustrating a SAW filter package structure according to furthermore preferred embodiment of the present invention.

DETAILED DESCRIPTION

(10) Reference will now be made to the drawings to describe various inventive embodiments of the present disclosure in detail, wherein like numerals refer to like elements throughout.

(11) As shown in FIG. 2, the surface acoustic wave filter package structure 200 according to the embodiment of the invention includes a dielectric substrate 21, a chip 33, a polymer sealing frame 31, a mold sealing layer 37 and a patterned protective layer 39.

(12) The dielectric substrate 21 includes a dielectric layer 25, a first patterned conductive layer 23, a second patterned conductive layer 29 and a conductive connection layer 27. Additionally, the dielectric substrate 21 includes a first side 211 and a second side 212, which are arranged oppositely.

(13) The dielectric layer 25 may be made of a dielectric material with high filler content, for example molding compound, main substrate such as Novolac-Based Resin, Epoxy-Based Resin or Silicone-Based Resin, which is about 8 wt. %-12 wt. % of the molding compound, and a filler which is about 70 wt. %-90 wt. % of the molding compound, wherein the filler may includes silicon dioxide and aluminum oxide to improve the mechanical strength, reduce the linear coefficient of thermal expansion, improve heat conduction and water resistance and reduce glue overflow.

(14) The first patterned conductive layer 23 is arranged in the dielectric layer 25 at the first side 211 of the dielectric substrate 21, and the first patterned conductive layer 23 is partially exposed at the surface of the dielectric layer 25. The first patterned conductive layer 23 further includes a conductive metal material, for example, copper, silver, nickel or their alloy.

(15) The second patterned conductive layer 29 is arranged on the dielectric layer 25 at the second side 212 of the dielectric substrate 21, and at least zoned to a conductive circuit portion 291, a conductive electrode portion 292 and a finger electrode portion 293 according to its role and connection relationship. Same with the first patterned conductive layer 23, the second patterned conductive layer 29 may include a conductive metal material, for example, copper, silver, nickel or their alloy.

(16) The conductive connection layer 27 is arranged in the dielectric layer 25, and electrically connected with the first patterned conductive layer 23 and the second patterned conductive layer 29. The conductive connection layer 27 may be a conductive pillar or a conductive blind hole. The conductive connection layer 27 may be made of same or different conductive metal material for the first patterned conductive layer 23 and the second patterned conductive layer 29, for example, copper.

(17) The chip 33 includes an active surface 331, the active surface 331 of the chip 33 faces towards the second side 212 of the dielectric substrate 21 and is arranged in such a way that the active surface 331 corresponds to the finger electrode portion 293 of the second patterned conductive layer 29. In the embodiment, the chip 33 is a surface acoustic wave (SAW) chip. Additionally, a plurality of electrical connecting pads 332 are arranged on the active surface 331 of the chip 33, the chip 33 is electrically connected with the conductive electrode portion 292 of the second patterned conductive layer 29 through the electrical connecting pads 332 and a conductive component 35, wherein the conductive component 35 is a conductive bump, a solder ball or a conducting resin. If the conductive bump is used, the conductive bump may include a gold bump, a eutectic solder bump, or high lead solder bump.

(18) The polymer sealing frame 31 is arranged between the chip 33 and the dielectric substrate 21, and surrounded at the periphery of the chip 33 to form a closed cavity 201 with the chip 33 and the dielectric substrate 21. The polymer sealing frame 31 is designed to maintain the sealed (airtight) status of the closed cavity 201, and its material may be a high polymer material with elasticity or compressibility. It is noted that the elasticity or compressibility refers to lower elastic coefficient rather than high elastic coefficient, and it may include the materials using rubber or resin as substrate.

(19) The mold sealing layer 37 is arranged on the dielectric substrate 21 and covers the chip 33 and the polymer sealing frame 31. Same with the dielectric layer 25, the mold sealing layer 37 may be made of the dielectric material with high filler content, for example, the molding compound.

(20) The patterned protective layer 39 is arranged on the dielectric layer 25 at the first side 211 of the dielectric substrate 21, and covers the surface of the dielectric layer 25, and partially first patterned conductive layer 23, wherein the first patterned conductive layer 23 exposed out of the patterned protective layer 39 may be used as the electric connecting pad (or welding pad) electrically connected with an external component (for example, a circuit board).

(21) As shown in FIGS. 3A-3J, the manufacturing method for the surface acoustic wave filter package structure 400 according to the embodiment of the invention includes Steps S01-S11.

(22) As shown in FIG. 3A, Step S01 is to provide a carrier board 40, and to arrange a first patterned conductive layer 43 on the surface of the carrier board 40. The carrier board 40 may include a metal board or an insulating board. If the metal board is used for the carrier board 40, its material is copper. On the other hand, if the insulating board is used for the carrier board 40, its material may be the mixture of ceramic, epoxy resin, polyimide, cyanide ester, carbon fiber or glass fiber. The first patterned conductive layer 43 may include a conductive metal material, such as copper, silver, nickel or their alloy. The first patterned conductive layer 43 may coordinate with an additional photoresist layer (not shown in the figure) to perform exposure and development process and the first patterned conductive layer 43 is formed on the carrier board 40 by electroplating process.

(23) As shown in FIG. 3B, Step S02 is to arrange a dielectric layer 45 on the surface of the carrier board 40 to cover the first patterned conductive layer 43, and formation of a plurality of openings on the dielectric layer 45 by laser drilling technology to partially expose the first patterned conductive layer 43.

(24) As shown in FIG. 3C, Step S03 is to arrange the conductive connection layer 47 in those openings shown in FIG. 3B, and to arrange a second patterned conductive layer 49 on the dielectric layer 45 and the conductive connection layer 47. Similar with the first patterned conductive layer 43, the conductive connection layer 47 and the second patterned conductive layer 49 may coordinate with an additional photoresist layer (not shown in the figure) to perform photolithography process including exposure and development process, and the conductive connection layer 47 is arranged in the opening 451 by the electroplating process, the second patterned conductive layer 49 is arranged on the dielectric layer 45 and the conductive connection layer 47. The second patterned conductive layer 49 may be zoned to a conductive circuit portion 491, a conductive electrode portion 492 and a finger electrode portion 493.

(25) For the convenience for of hereinafter description, it is thereby stated that the first patterned conductive layer 43, the dielectric layer 45, the conductive connection layer 47 and the second patterned conductive layer 49 may be called as the dielectric substrate 41 including the first side 411 and the second side 412, which are arranged oppositely, wherein the side of the dielectric substrate 41 contacting the carrier board 40 is the first side 411. Additionally, the dielectric substrate 41 manufactured by the above-mentioned process is an ultrathin substrate with not more than 100 micron thickness.

(26) As shown in FIG. 3D, Step S04 is to arrange a polymer sealing layer 51 on the second side 412 of the dielectric substrate 41, in other words, the polymer sealing layer 51 is arranged onto the dielectric layer 45 and the second patterned conductive layer 49.

(27) As shown in FIG. 3E, Step S05 is to form a plurality of openings 511 on the polymer sealing layer 51 to partially expose second patterned conductive layer 49 to form a plurality of the polymer sealing frames 51-1 and 51-2.

(28) As shown in FIG. 3F, Step S06 is to arrange a plurality of the chips 53-1, 53-2 on corresponding polymer sealing frames 51-1 and 51-2, wherein, the active surfaces 531-1, 531-2 of the chips 53-1, 53-2 face towards the second side 412 of the dielectric substrate 41. In the embodiment, the electrical connecting pad 532 is arranged on the active surfaces 531-1, 531-2 of the he chips 53-1, 53-2, respectively corresponding to the conductive electrode portion 492 of the second patterned conductive layer 49, to achieve their electrical connection by the conductive component 55, wherein the conductive component 55 may be the conductive bump, the solder ball or the conducting resin, which is formed by printing process or dispensing process.

(29) The polymer sealing frames 51-1, 51-2 and the chips 53-1, 53-2 form the closed cavities 401-1, 401-2 together with the dielectric substrate 41, and the finger electrode portion 493 of the second patterned conductive layer 49 is located in the closed cavities 401-1, 401-2.

(30) It is to be noted, the chip arranged in single wafer can be simultaneously packaged by traditional wafer level process, with such disadvantages such as time-consuming, various process limitations. Comparing with the traditional wafer level package process, panel level packaging process is used for this invention; that is, the area of the carrier board 40 is plural times of the area of single wafer. All chips cut from a plurality of the wafers can be simultaneously packed by the carrier board 40 with large size according to this invention to effectively reduce the manufacturing process time.

(31) As shown in FIG. 3G, Step S07 is to arrange a mold sealing layer 57 by a molding process to cover the chips 53-1, 53-2 and the polymer sealing frames 51-1, 51-2. In the embodiment, the mold sealing layer 57 may be made of same with or different from the material of dielectric layer 45, including the dielectric material with high filler content, for example, the molding compound, main substrate such as phenolic resin, epoxy resin or silicone resin, which is about 8 wt. %-12 wt. % of the molding compound, and a filler which is about 70 wt. %-90 wt. % of the molding compound, wherein the filler may includes silicon dioxide and aluminum oxide to improve the mechanical strength, reduce the linear coefficient of thermal expansion, improve heat conduction and water resistance and reduce glue overflow.

(32) As shown in FIG. 3H, Step S08 is to remove the carrier board 40.

(33) As shown in FIG. 3I, Step S09 is to arrange the patterned protective layer 59 on the first side 411 of the dielectric substrate 41 to complete the SAW filter package structure 400. In other words, the patterned protective layer 59 is arranged on the dielectric layer 45 and the first patterned conductive layer 43, wherein the opening 591 of the patterned protective layer 59 is formed by the laser drilling technology.

(34) Finally, as shown in FIG. 3J, Step S10 is to cut the package structure 400 shown in FIG. 3I into independent SAW filter package structures 400-1, 400-2.

(35) Continued to the above, as shown in FIG. 4 and described above, exampling the SAW filter package structure 400-1, the polymer sealing frame 51-1 and the chip 53-1 of the SAW filter package structure 400-1 has a closed overlapped area OV1 in the orthographic projection direction (e.g. overlook). The closed overlapped area OV1 is designed to prevent damaging the cavity structure by overflow of the raw material for the mold sealing layer 57 into the closed cavity 401-1 during arrangement of the mold sealing layer 57.

(36) As shown in FIG. 2, in the aforementioned embodiment, the surface of the first patterned conductive layer 23 aligns with the surface of the dielectric layer 25 at the first side 211 of the dielectric substrate 21; the surface of the second patterned conductive layer 29 extrudes out of the surface of the dielectric layer 25 at the second side 212 of the dielectric substrate 21. In other embodiment, the surface of the first patterned conductive layer extrudes out of the surface of the dielectric layer at the first side of the dielectric substrate, and the surface of the second patterned conductive layer aligns with the surface of the dielectric layer at the second side of the dielectric substrate.

(37) As shown in FIGS. 5 and 6, the implementation method is simply described for alignment of the surface of the second patterned conductive layer with the surface of the dielectric layer at the second side of the dielectric substrate.

(38) As shown in FIG. 5, the step is performed after the Step S03 shown in FIG. 3C of the above-mentioned embodiment, and includes arrangement of another dielectric layer 45a on the dielectric layer 45 and the second patterned conductive layer 49 after arrangement of the second patterned conductive layer 49, and thinning the dielectric layer 45a by grinding process and exposing the surface of the second patterned conductive layer 49 to align with the surface with dielectric layer 45a. After completion of this step, Step S04 is performed, and subsequent steps are not repeated herein.

(39) The SAW filter package structure manufactured hereby is shown in FIG. 6, the surface of the second patterned conductive layer 49 of the SAW filter package structure 400a aligns with the surface of the dielectric layer 45a at the second side 412 of the dielectric substrate 41. Further speaking, the surface of the second patterned conductive layer 49 is in same plane with the surface of the dielectric layer 45a and the polymer sealing frame 51-1.

(40) Furthermore, in the above-mentioned embodiment, the side of the polymer sealing frame of the cut SAW filter package structure is exposed out of the mold sealing layer. In other embodiment, the side of the polymer sealing frame may be clad in the mold sealing layer to prevent fracturing and separating resulting from connection degradation.

(41) As shown in FIGS. 7 and 8, a method is simply described for cladding the side of the polymer sealing frame in the mold sealing layer.

(42) As shown in FIG. 7, the step is performed after the Step S04 shown in FIG. 3D of the above-mentioned embodiment, and includes formation of a plurality of opening 511 and 511a on the polymer sealing layer 51 by corrosion technology to partially expose the second patterned conductive layer 49. After completion of this step, Step S06-Step S10 are performed to manufacture the SAW filter package structure 400b as shown in FIG. 8, wherein the side of the polymer sealing frame 51-1 is clad in the mold sealing layer 57.

(43) In conclusion, the SAW filter package structure according to this invention and manufacturing method thereof have the functional characteristics: 1. By panel level packaging, the chips for the plurality of the wafers are packaged in batch to improve production efficiency, and so, compared with the conventional WLCSP, this invention can achieve several times yield of the prior art and improve process efficiency and reduce cost significantly. 2. In this invention, a high polymer material is used as the polymer sealing frame to improve whole structure rigidity and sealing property together with cladding the mold sealing layer, and so, the SAW filter package structure according to this invention may be used in worse working environment with higher reliability and efficiency. 3. In this invention, after arrangement of the chip 33, the chip 33 is packaged by the mold sealing layer 37 to ensure that the chip 33 is not polluted or damaged in the subsequent process, so the yield can be improved. 4. The lower chip 11 of the traditional surface acoustic wave filter package structure is replaced with the thinned dielectric substrates 21, 41 to effectively thin the SAW filter package structure, which can fully meet elastic application environment requirements.

(44) Even though numerous characteristics and advantages of certain inventive embodiments have been set out in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only. Changes may be made in detail, especially in matters of arrangement of parts, within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.