In some embodiments, an interconnection structure and a dielectric structure are formed over the devices on the substrate 20. The interconnection structure is formed in the dielectric structure and connected to different devices to form a functional circuit. In some embodiments, the dielectric structure includes an inter-layer dielectric layer (ILD) and one or more inter-metal dielectric layers (IMD). In some embodiments, the interconnection structure includes multiple layers of metal lines and plugs (not shown). The metal lines and plugs include conductive materials, such as metal, metal alloy or a combination thereof. For example, the conductive material may include tungsten (W), copper (Cu), copper alloys, aluminum (Al), aluminum alloys, or combinations thereof. The plugs include contact plugs and via plugs. The contact plugs are located in the ILD to be connected to the metal lines and the devices. The via plugs are located in the IMD to be connected to the metal lines in different layers.

The pads 21 may be or electrically connected to a top conductive feature of the interconnection structure, and further electrically connected to the devices formed on the substrate 20 through the interconnection structure. The material of the pads 21 may include metal or metal alloy, such as aluminum, copper, nickel, or alloys thereof.

The passivation layer 22 is formed over the substrate 20 and covers a portion of the pads 21. Another portion of the pads 21 is exposed by the passivation layer 22 and serves as an external connection of the die 25. The connectors 23 are formed on and electrically connected to the pads 21 not covered by the passivation layer 22. The connector 23 includes solder bumps, gold bumps, copper bumps, copper posts, copper pillars, or the like. The passivation layer 24 is formed over the passivation layer 22 and laterally aside the connectors 23 to cover the sidewalls of the connectors 23. The passivation layers 22 and 24 respectively include an insulating material such as silicon oxide, silicon nitride, polymer, or a combination thereof. The polymer may include polybenzoxazole (PBO), polyimide (PI), benzocyclobutene (BCB), the like, or combinations thereof. The materials of the passivation layer 22 and the passivation layer 24 may be the same or different. In some embodiments, the top surface of the passivation layer 24 and the top surfaces of the connectors 23 are substantially coplanar with each other.

Referring to FIG. 1D, an encapsulant material layer 28 is then formed over the carrier 10 to encapsulate the die 25, the TIVs 15 and the adhesion promoter material layer 18. Specifically, the encapsulant material layer 28 is formed on the polymer layer 12, encapsulating sidewalls and top surfaces of the die 30, sidewalls and top surfaces of the adhesion promoter material layer 18. The adhesion promoter material layer 18 is sandwiched between the TIVs 15 and the encapsulant material layer 28. In some embodiments, the adhesion promoter material layer 18 includes a functional group (such as the functional group X, Y, Z in the above formulas) which may react with the encapsulant material layer 28, and chemical bonds may be formed between the adhesion promoter material layer 18 and the encapsulant material layer 28.

In some embodiments, the encapsulant material layer 28 includes a molding compound, a molding underfill, a resin such as epoxy, a combination thereof, or the like. In some other embodiments, the encapsulant material layer 28 includes a photo-sensitive material such as polybenzoxazole (PBO), polyimide (PI), benzocyclobutene (BCB), a combination thereof, or the like, which may be easily patterned by exposure and development processes or laser drilling process. In alternative embodiments, the encapsulant material layer 28 includes nitride such as silicon nitride, oxide such as silicon oxide, phosphosilicate glass (PSG), borosilicate glass (BSG), boron-doped phosphosilicate glass (BPSG), a combination thereof, or the like.

In some embodiments, the encapsulant material layer 28 includes a composite material including a base material (such as polymer) and a plurality of fillers distributed in the base material. The filler may be a single element, a compound such as nitride, oxide, or a combination thereof. The fillers may include silicon oxide, aluminum oxide, boron nitride, alumina, silica, or the like, for example. In some embodiments, the fillers may be spherical fillers, but the disclosure is not limited thereto. The cross-section shape of the filler may be circle, oval, or any other shape. In some embodiments, the encapsulant material layer 28 is formed by a suitable fabrication technique such as molding, spin-coating, lamination, deposition, or similar processes.

Referring to FIG. 1E, in some embodiments, a planarization process is performed to remove a portion of the encapsulant material layer 28 over the top surfaces of the die 25 and the TIVs 15 and portions of the adhesion promoter material layers 18 on the top surfaces of the TIVs 15, such that the top surfaces of the connectors 23 of the die 25 and the top surfaces of the TIVs 15 are exposed. The planarization process includes a grinding or polishing process such as a chemical mechanical polishing (CMP) process.

Still referring to FIG. 1E, after the planarization process is performed, a plurality of adhesion promoter layers 18a and an encapsulant 28a are formed. The adhesion promoter layers 18a are located on the polymer layer 12 and laterally aside the TIVs 15, surrounding the sidewalls of the TIVs 15. The encapsulant 28a is located on the polymer layer 12 and laterally aside the die 25, the adhesion promoter layer 18a and the TIVs 15, encapsulating sidewalls of the die 25, sidewalls of the adhesion promoter layer 18a and sidewalls of the TIVs 15. The adhesion promoter layer 18a is sandwiched between and in physical contact with the TIV 15 and the encapsulant 28a. In other word, the encapsulant 28a is not in direct physical contact with the TIV 15, and separated from the TIV 15 by the adhesion promoter layer 18a therebetween. In some embodiments, the top surface of the die 25, the top surfaces of the TIVs 15, the top surface of the adhesion promoter layer 18a and the top surface of the encapsulant 28a are substantially coplanar with each other.

Referring to FIG. 1F, a redistribution layer (RDL) structure 32 is formed on the die 25, the TIVs 15, and the encapsulant 28a. The RDL structure 32 is electrically connected to the die 25 and the TIVs 15. In some embodiments, the RDL structure 32 is referred to as a front-side RDL structure of the die 30. Through the specification, wherein the “front-side” refers to a side close to the connectors of the die.

In some embodiments, the RDL structure 32 includes a plurality of polymer layers PM1, PM2 and PM3 and a plurality of redistribution layers RDL1 and RDL2 stacked alternately. The number of the polymer layers or the redistribution layers shown in FIG. 1F is merely for illustration, and the disclosure is not limited thereto.

The redistribution layer RDL1 penetrates through the polymer layer PM1 and is electrically connected to the connectors 23 of the die 25 and the TIVs 15. The redistribution layer RDL2 penetrates through the polymer layer PM2 and is electrically connected to the redistribution layer RDL1. The polymer layer PM3 is located on and covers the polymer layer PM2 and the redistribution layer RLD2.

In some embodiments, each of the polymer layers PM1, PM2, and PM3 includes a photo-sensitive material such as polybenzoxazole (PBO), polyimide (PI), benzocyclobutene (BCB), a combination thereof or the like. In some embodiments, each of the redistribution layers RDL1 and RDL2 includes conductive materials. The conductive materials includes metal such as copper, aluminum, nickel, titanium, alloys thereof, a combination thereof or the like, and is formed by a physical vapor deposition (PVD) process such as sputtering, a plating process such as electroplating, or a combination thereof. In some embodiments, the redistribution layers RDL1 and RDL2 include a seed layer SL and a conductive layer CL formed thereon, respectively. The seed layer SL may be a metal seed layer such as a copper seed layer. In some embodiments, the seed layer includes a first seed layer such as a titanium layer and a second seed layer such as a copper layer over the first seed layer. The metal layer may be copper or other suitable metals.

In some embodiments, the redistribution layers RDL1 and RDL2 respectively includes a plurality of vias V and a plurality of traces T connected to each other. The vias V are embedded in and penetrate through the polymer layers PM1 and PM2, to connect the traces T of the redistribution layers RDL1 and RDL2, and the traces T are located on the polymer layers PM1 and PM2, and are extending on the top surface of the polymer layers PM1 and PM2, respectively.

Still referring to FIG. 1F, in some embodiments, the polymer layer PM3 is patterned to form a plurality of openings 34. The openings 34 expose a portion of the top surface of the redistribution layer RDL2. In some embodiments, conductive terminals may be formed on the redistribution layer RDL2 exposed by the openings 34, but the disclosure is not limited thereto. In alternative embodiments, a plurality of TIVs may be formed on the redistribution layer RDL2, and one or more dies may further be stacked on the RDL structure 32.

Referring to FIG. 1G, in some embodiments, a plurality of the TIVs 37 are formed on the redistribution layer RDL2 exposed by the openings 34 of the polymer layer PM3. The TIV 37 includes a seed layer 35 and a conductive post 36 on the seed layer 35. The materials and forming method of the TIV 37 are similar to, and may be the same as or different from those of the TIV 15. In some embodiments, the seed layer 35 is a metal seed layer such as a copper seed layer. For example, the seed layer 35 may include titanium, copper, the like, or a combination thereof. In some embodiments, the seed layer 35 includes a first seed layer 35a such as a titanium layer and a second seed layer 35b such as a copper layer over the first seed layer 35a (FIG. 2B). The conductive post 36 includes a suitable metal, such as copper. The seed layer 35 covers the surface of the opening 34 and a portion of the top surface of the polymer layer PM3. The conductive post 36 covers the surface of the seed layer 35, filling the opening 34 and protruding from the top surface of the polymer layer PM3. It is noted that, the number of the TIVs 37 shown in FIG. 1G is merely for illustration, and the disclosure is not limited thereto.

Referring to FIG. 1H, an adhesion promoter material layer 38 is then formed to cover the sidewalls and top surfaces of the TIVs 37. In some embodiments, the adhesion promoter material layer 38 includes a metal chelate, such as copper chelate. The forming method of the adhesion promoter material layer 38 is similar to, and may be substantially the same as or different form that of the adhesion promoter material layer 18, which is not described again here.

The adhesion promoter material layer 38 covers the sidewalls and the top surface of the conductive post 36, and the sidewalls of the seed layer 35 on the top surface of the polymer layer PM3.

Referring to FIG. 1I, a die 45 is mounted on the polymer layer PM3 of the RDL structure 32 by pick and place processes. In some embodiments, the die 45 is attached to the polymer layer PM3 through an adhesive layer 39 such as a die attach film (DAF), silver paste, or the like. The die 45 may be an application-specific integrated circuit (ASIC) chip, an analog chip, a sensor chip, a wireless and radio frequency chip, a voltage regulator chip or a memory chips. The number of the die 45 shown in FIG. 1I is merely for illustration, and the disclosure is not limited thereto. In some embodiments, two or more dies 45 may be mounted on the polymer layer PM3 of the RDL structure 32, and the two or more dies 45 may be the same types of dies or the different types of dies. The die 45 and the die 25 may be the same types of dies or different types of dies. The structure of the die 45 is similar to, and may be the same as or different from the structure of the die 25.

In some embodiments, the die 45 includes a substrate 40, a plurality of pads 41, a passivation layer 42, a plurality of connectors 43 and a passivation layer 44. The materials, forming method, and structural features of the substrate 40, the pads 41, the passivation layer 42, the connectors 43 and the passivation layer 44 of the die 45 are substantially the same as those of the die 25, which are not described again here.

Still referring to FIG. 1I, an encapsulant material layer 48 is then formed on the RDL structure 32 to encapsulant sidewalls and top surfaces of the die 45, the TIVs 37 and the adhesion promoter material layer 38. The material and forming method of the encapsulant material layer 48 are similar to, and may be the same as or different from those of the encapsulant material layer 28 (FIG. 1D).

Referring to FIG. 1J, in some embodiments, a planarization process is then performed to expose the top surfaces of the connectors 43 of the die 45 and top surfaces of the TIVs 37. The planarization process may include a grinding or polishing process such as a CMP process. In some embodiments, a portion of the encapsulant material layer 48 over the top surfaces of the die 45 and the TIVs 37 and portions of the adhesion promoter material layer 38 on the top surfaces of the TIVs 37 are removed by the planarization process, and an encapsulant 48a and an adhesion promoter layer 38a are remained. In some embodiments, after the planarization process is performed, the top surface of the die 45, the top surfaces of the TIVs 37, the top surfaces of the adhesion promoter layers 38a and the top surface of the encapsulant 48a are substantially coplanar with each other.

Referring to FIG. 1K, a RDL structure 52 is then formed on the die 45, the TIVs 37 and the encapsulant 48a. The RDL structure 52 is electrically connected to the die 45 and the TIVs 37. In some embodiments, the RDL structure 52 includes a plurality of polymer layers PM10, PM20, PM30 and PM40, and a plurality of redistribution layers RDL10, RDL20, RDL30 and RDL40 stacked alternately. The number of the polymer layers or the redistribution layers shown in FIG. 1K is merely for illustration, and the disclosure is not limited thereto. The materials and forming method of the polymer layers and redistribution layers of the RDL structure 52 are similar to, and may be the same as or different from those of the RDL structure 32.

The redistribution layer RDL10 penetrates through the polymer layer PM10 and is electrically connected to the connectors 43 of the die 45 and the TIVs 37. The redistribution layer RDL20 penetrates through the polymer layer PM20 and is electrically connected to the redistribution layer RDL10. The redistribution layer RDL30 penetrates through the polymer layer PM30 and is electrically connected to the redistribution layer RDL20. The redistribution layer RDL40 penetrates through the polymer layer PM40 and is electrically connected to the redistribution layer RDL30.

In some embodiments, similar to the redistribution layers RDL1 and RDL2, the redistribution layers RDL10, RDL20, RDL30, and RDL40 include a seed layer SL and a conductive layer CL formed thereon, respectively. In some embodiments, the redistribution layers RDL10, RDL20, RDL30 respectively includes a plurality of vias V and a plurality of traces T connected to each other. The vias V are embedded in and penetrate through the polymer layers PM10, PM20, PM30, to connect the traces T of the redistribution layers RDL10, RDL20, RDL30, the traces T are located on the polymer layers PM10, PM20, PM30, and are extending on the top surface of the polymer layers PM10, PM20, PM30, respectively.

In some embodiments, the redistribution layer RDL40 is the topmost redistribution layer of the RDL structure 52, and is referred to as under-ball metallurgy (UBM) layer for ball mounting.

Still referring to FIG. 1K, a plurality of connectors 56 are formed over and electrically connected to the redistribution layer RDL40 of the RDL structure 52. In some embodiments, the connectors 56 are referred as conductive terminals. In some embodiments, the connectors 56 may be ball grid array (BGA) connectors, solder balls, controlled collapse chip connection (C4) bumps, or a combination thereof. In some embodiments, the material of the connector 56 includes copper, aluminum, lead-free alloys (e.g., gold, tin, silver, aluminum, or copper alloys) or lead alloys (e.g., lead-tin alloys). The connector 56 may be formed by a suitable process such as evaporation, plating, ball dropping, screen printing and reflow process, a ball mounting process or a C4 process. In some embodiments, metal posts or metal pillars (not shown) may further be formed between the redistribution layer RDL40 and the connectors 56, but the disclosure is not limited thereto. The connectors 56 are electrically connected to the connectors 43 of the die 45 and the TIVs 37 through the RDL structure 52, and further electrically connected to the connectors 23 of the die 25 and the TIVs 15 through the RDL structure 32.

Referring to FIG. 1K and FIG. 1L, in some embodiments, the de-bonding layer 11 is decomposed under the heat of light, and the carrier 10 is then released from the overlying structure, and a package structure 100a is thus formed. In some embodiments, the package structure 100a may further be coupled to other package structures to form a package on package (PoP) device.

Referring to FIG. 1L and FIG. 1M, portions of the polymer layer 12 may be removed by a laser drilling process to form openings OP in the polymer layer 12. The openings OP expose portions of the bottom surfaces of TIVs 15. Thereafter, the package structure 100a is electrically connected to a package structure 200 to form a PoP device 300 through a plurality of connectors 54. The connectors 54 fill in the openings OP and are electrically connected to the TIVs 15. The package structure 100a and the package structure 200 may include the same types of devices or the different types of devices. The package structure 200 may include active devices, passive devices, or combinations thereof. In some embodiments, the package structure 200 is a memory, such as dynamic random access memory (DRAM), static random access memory (SRAM), or other type of memory. In some embodiments, an underfill layer UF may further be formed to fill the space between the package structure 100a and the package structure 200 and surround the connectors 54.

Referring to FIG. 1L, in some embodiments, the package structure 100a includes the polymer layer 12, the die 25, the TIVs 15, the adhesion promoter layers 18a, the encapsulant 28a, the RDL structure 32, the die 45, the TIVs 37, the adhesion promoter layers 38a, the encapsulant 48a, the RDL structure 52 and the connectors 56. The die 25 and the die 45 are electrically connected to each other through the RDL structure 32, the TIVs 37 and the RDL structure 52. In some embodiments, the polymer layer 12 is disposed on back side of the die 25, the RDL structure 32 is disposed on front side of the die 25 and on back side of the die 45, and the RDL structure 52 is disposed on the front side of the die 45.

The TIVs 15 are laterally aside the die 25, and the encapsulant 28a are laterally aside the die 25 and the TIVs 15, encapsulating sidewalls of the die 25 and sidewalls of the TIVs 15. In some embodiments, the adhesion promoter layers 18a are sandwiched between and in physical contact with the TIVs 15 and the encapsulant 28a. In other words, the sidewalls of the TIVs 15 are covered by the adhesion promoter layers 18a, and separated from the encapsulant 28a by the adhesion promoter layer 18a therebetween. The sidewalls of the adhesion promoter layers 18a are laterally encapsulated by the encapsulant