The invention relates to package structures and fabrication methods thereof, and more particularly, to a package structure having a circuit structure and a fabrication method thereof.
Flip-chip technologies facilitate to reduce chip packaging sizes and shorten signal transmission paths and therefore have been widely used for chip packaging. Various types of packages such as chip scale packages (CSPs), direct chip attached (DCA) packages and multi-chip module (MCM) packages can be achieved through flip-chip technologies.
In a flip-chip packaging process, a big CTE (Coefficient of Thermal Expansion) mismatch between a chip and a packaging substrate adversely affects the formation of joints between conductive bumps of the chip and corresponding contacts of the packaging substrate, thus easily resulting in delamination of the conductive bumps from the packaging substrate. On the other hand, along with increased integration of integrated circuits, the CTE mismatch between the chip and the packaging substrate induces more thermal stresses and leads to more serious warpage, thereby reducing the product reliability and resulting in failure of a reliability test.
Accordingly, the process having an interposer structure composed of semiconductor material is provided. A silicon interposer is disposed between the packaging substrate and the semiconductor chip. Since the silicon interposer is close in material to the semiconductor chip, the above-described drawbacks caused by a CITE mismatch can be effectively overcome.
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For example, a packaging substrate generally has a minimum line width/pitch of 12/12 um. When the I/O count of a semiconductor chip increases, since the line width/pitch of the packaging substrate cannot be reduced, the area of the packaging substrate must be increased such that more circuits can be formed on the packaging substrate and electrically connected to the semiconductor chip having high I/O count. On the other hand, referring to
However, the TSVs 121 of the silicon interposer 12 used for electrically connecting the semiconductor chip 11 and the packaging substrate 13 incur a high fabrication cost. In addition, the silicon interposer 12 leads to an increase of the thickness of the final package structure.
Therefore, how to overcome the above-described drawbacks has become critical.
In view of the above-described drawbacks, the invention provides a package structure, which comprises: a frame having a cavity penetrating therethrough; at least a semiconductor chip received in the cavity of the frame, wherein the semiconductor chip has opposite active and inactive surfaces exposed from the cavity of the frame; a dielectric layer formed in the cavity to contact and fix in position the semiconductor chip, wherein a surface of the dielectric layer is flush with a first surface of the frame toward which the active surface of the semiconductor chip faces; and a circuit structure formed on the surface of the dielectric layer flush with the first surface of the frame and electrically connected to the active surface of the semiconductor chip.
In another embodiment, the invention further provides a package structure which comprises: a frame having a cavity penetrating therethrough; a semiconductor chip received in the cavity of the frame, wherein the semiconductor chip has opposite active and inactive surfaces exposed from the cavity of the frame; a dielectric layer formed in the cavity to contact and fix in position the semiconductor chip; a circuit structure formed on a surface of the dielectric layer toward which the active surface of the semiconductor chip faces and electrically connected to the active surface of the semiconductor chip; and a carrier disposed on the frame, the dielectric layer and the inactive surface of the semiconductor chip, wherein the frame and the carrier are not integrally formed.
The invention further provides a method for fabricating a package structure, which comprises the steps of: forming a frame on a carrier and disposing at least a semiconductor chip on the carrier, wherein the carrier has opposite first and second surfaces, the frame is formed on the first surface of the carrier and has a cavity exposing a portion of the first surface of the carrier, the frame and the carrier are not integrally formed, the semiconductor chip is received in the cavity of the frame and disposed on the portion of the first surface of the carrier exposed from the cavity and has an inactive surface attached to the first surface of the carrier and an active surface opposite to the inactive surface, and a dielectric layer is filled in the cavity to contact and fix in position the semiconductor chip; forming a circuit structure on the dielectric layer, wherein the circuit structure is electrically connected to the active surface of the semiconductor chip; and removing the carrier to expose the inactive surface of the semiconductor chip.
In an embodiment, forming the frame on the carrier and disposing the semiconductor chip on the carrier comprise the steps of: disposing the semiconductor chip on the carrier, disposing a cover board on the carrier, wherein the cover board has a recessed portion facing the carrier and receiving the semiconductor chip; removing a portion of the cover board to expose the semiconductor chip, so as for the remaining portion of the cover board to form the frame having the cavity formed from the recessed portion; and forming in the cavity of the frame the dielectric layer exposing at least a portion of the active surface of the semiconductor chip.
In another embodiment, forming the frame and the dielectric layer comprise the steps of: disposing the semiconductor chip and a cover board having a recessed portion on the carrier, wherein the recessed portion of the cover board faces the carrier for the semiconductor chip to be received in the recessed portion and attached to a bottom surface of the recessed portion, allowing the cover board to be positioned over and not in contact with the carrier, forming the dielectric layer in the recessed portion and between the cover board and the carrier to contact and fix in position the semiconductor chip; and removing a portion of the cover board to expose the semiconductor chip, so as for the remaining portion of the cover board to form the frame.
Therefore, the invention replaces the high cost conventional interposer with a low cost circuit structure and dispenses with the conventional solder balls formed between the semiconductor chip and the interposer, thereby effectively reducing the fabrication cost and the thickness of the package structure.
The following illustrative embodiments are provided to illustrate the disclosure of the present invention, these and other advantages and effects can be apparent to those in the art after reading this specification.
It should be noted that all the drawings are not intended to limit the present invention. Various modifications and variations can be made without departing from the spirit of the present invention. Further, terms such as “first”, “second”, “on”, “a” etc. are merely for illustrative purposes and should not be construed to limit the scope of the present invention.
Referring to
The carrier 20 and the cover board 21 can be made of an organic material such as BCB (Benzocyclobutene) or polyimide, or an inorganic material such as SiC or SiO2. The carrier 20 and the cover board 21 can be made of metal, glass, ceramic, or a semiconductor material such as Si or GaAs.
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The photosensitive material layer can be a photosensitive spin-on dielectric (PSOD) material such as a photodefinable polybenzobisoxazole (PBO) precursor, or a photodefinable material such as polyimide precursor, or a photosensitive patternable material such as a polysilsesquiazane composition.
Then, the cover board 21 is disposed on the carrier 20, with the recessed portion 210 facing the carrier 20 for receiving the semiconductor chips 22 therein. The cover board 21 is disposed on the carrier 20 by fusion bonding or adhesion.
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In another embodiment, a package structure of
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The invention further provides a package structure, which has: a frame 21′ having a cavity 210′ penetrating therethrough; at least a semiconductor chip 22 received in the cavity 210′ of the frame 21′, wherein the semiconductor chip 22 has opposite active and inactive surfaces 22a, 22b exposed from the cavity 210′ of the frame 21; a dielectric layer 23 formed in the cavity 210′ to contact and fix in position the semiconductor chip 22, wherein a surface of the dielectric layer 23 is flush with a first surface of the frame 21′ toward which the active surface 22a of the semiconductor chip 22 faces; and a circuit structure 25 formed on the surface of the dielectric layer 23 flush with the first surface of the frame 21′ and electrically connected to the active surface 22a of the semiconductor chip 22.
In an embodiment, referring to
In an embodiment, referring to
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In another embodiment, both the active and inactive surfaces 22a, 22b of the semiconductor chip 22 are completely exposed from the dielectric layer 23. The package structure further has a built-up dielectric layer 23′ formed on the dielectric layer 23 at the side of the active surface 22a of the semiconductor chip 22 and a plurality of conductors 24 formed in the built-up dielectric layer 23′. The circuit structure 25 is formed on the built-up dielectric layer 23′ and electrically connected to the active surface 22a of the semiconductor chip 22 through the conductors 24. In the present embodiment, referring to
In another embodiment, both the active and inactive surfaces 22a, 22b of the semiconductor chip 22 are completely exposed from the dielectric layer 23. The circuit structure 25 is in contact and electrical connection with the active surface 22a of the semiconductor chip 22. Referring to
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Referring to HG 3B′, the package structure has a carrier 20. Both the active and inactive surfaces 22a, 22b of the semiconductor chip 22 are completely exposed from the dielectric layer 23. The circuit structure 25 is in contact and electrical connection with the active surface 22a of the semiconductor chip 22.
The package structure can further have a plurality of conductive elements 27 formed on the circuit structure 25 and electrically connected the circuit structure 25.
The package structure can further have a substrate 28 disposed on and electrically connected to the circuit structure 25 through the conductive elements 27.
Therefore, the invention replaces the conventional interposer with a cheap circuit structure and dispenses with the conventional solder balls formed between the semiconductor chip and the interposer, thereby effectively reducing the fabrication cost and the thickness of the package structure. Further, since the carrier provides a rigid support to the package structure during formation of the circuit structure or disposing of the substrate, the invention avoids warpage of the package structure. Furthermore, the inactive surface of the semiconductor chip can be exposed for heat dissipation. In addition, since the semiconductor chip is fixed by the frame of the invention, the invention prevents positional deviation of the semiconductor chip during the fabrication process.
The above-described descriptions of the detailed embodiments are only to illustrate the preferred implementation according to the present invention, and it is not to limit the scope of the present invention. Accordingly, all modifications and variations completed by those with ordinary skill in the art should fall within the scope of present invention defined by the appended claims.
Number | Date | Country | Kind |
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103131299 A | Sep 2014 | TW | national |
This application is a divisional of copending application U.S. Ser. No. 14/823,341, filed on Aug. 11, 2015, which claims under 35 U.S.C. § 119(a) the benefit of Taiwanese Application No. 103131299, filed Sep. 11, 2014, the entire contents of which are incorporated herein by reference.
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Number | Date | Country | |
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Parent | 14823341 | Aug 2015 | US |
Child | 16225230 | US |