MANUFACTURING METHOD OF PACKAGE-ON-PACKAGE STRUCTURE
A manufacturing method of a package-on package structure including at least the following steps is provided. A die is bonded on a first circuit carrier. A spacer is disposed on the die. The spacer and the first circuit carrier are connected through a plurality of conductive wires. An encapsulant is formed to encapsulate the die, the spacer and the conductive wires. A thickness of the encapsulant is reduced until at least a portion of each of the conductive wires is removed to form a first package structure. A second package structure is stacked on the first package structure. The second package structure is electrically connected to the conductive wires.
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This application claims the priority benefit of U.S. provisional application Ser. No. 62/410,851, filed on Oct. 21, 2016. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of the specification.
BACKGROUND OF THE INVENTION 1. Field of the InventionThe present invention generally relates to a manufacturing method of a package structure, and more particularly relates to a manufacturing method of a package-on-package (POP) structure.
2. Description of Related ArtIn order for electronic product design to achieve being light, slim, short, and small, semiconductor packaging technology has kept progressing, in attempt to develop products that are smaller in volume, lighter in weight, higher in integration, and more competitive in the market. For example, 3D stacking technologies such as POP have been developed to meet the requirements of higher packaging densities. As such, how to achieve a thinner POP structure with lower manufacturing cost has become a challenge to researchers in the field.
SUMMARY OF THE INVENTIONThe disclosure provides a manufacturing method of a package-on-package (POP) structure, which reduces the overall thickness and the manufacturing cost thereof.
The disclosure provides a manufacturing method of a POP structure. The method includes at least the following steps. A die is bonded on a first circuit carrier. A spacer is disposed on the die. The spacer and the first circuit carrier are connected through a plurality of conductive wires. An encapsulant is formed to encapsulate the die, the spacer and the conductive wires. A thickness of the encapsulant is reduced until at least a portion of each of the conductive wires is removed to form a first package structure. A second package structure is stacked on the first package structure. The second package structure is electrically connected to the conductive wires.
Based on the above, the spacer disposed on the die is conducive to form the conductive wires. In addition, since the thickness of the encapsulant is reduced and also at least a portion of each of the conductive wires is removed to form a first package structure, the rest portion of the conductive wires in the encapsulant may serve as the electrical connecting path between the first package structure and the second package structure. In other word, it is unnecessary to dispose additional interposer between the first package structure and the second package structure for electrical connection. Hence, the overall thickness of the POP structure may be reduced and the lower manufacturing costs may be achieved.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
Reference will now be made in detail to the present preferred embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
The core layer 112 may further include embedded circuit layers serving as an intermediate circuit layer electrically connected to the top circuit layer 114 and the bottom circuit layer 116. The core layer 112 may include a base layer and a plurality of conductive vias penetrating through the base layer. The two opposite ends of the conductive vias of the core layer 112 may electrically connect to the conductive pads 114a of the top circuit layer 114 and the conductive pads 116a of the bottom circuit layer 116. In some embodiments, the first package structure 100 may include a plurality of conductive structures 118 formed on the bottom surface S2 of the first package structure 100. For example, a material of the conductive structures 118 may include copper, tin, gold, nickel or other suitable conductive material. The conductive structures 118 may be, for example, conductive bumps, conductive pillars, or solder balls formed by a ball placement process and a reflow process. It should be noted that other possible forms and shapes of the conductive structures 118 may be utilized for further electrical connection. In some embodiments, the conductive structures 118 may form an array arranged to have fine pitch on the bottom surface S2 of the first circuit carrier 110 for requirement in the subsequent processes.
A first die 120 may be disposed on the top surface S1 of the first circuit carrier 110. The first die 120 may be electrically connected to the first circuit carrier 110 through flip-chip bonding. In some embodiment, an active surface (not illustrated) of the first die 120 is coupled to the conductive pads 114a of the top circuit layer 114 of the first circuit carrier 110 through a plurality of conductive bumps 122. The conductive bumps 122 may be copper bumps. In some embodiments, solders (not illustrated) may be applied onto surfaces of the conductive bumps 122 to couple with the conductive pads 114a. The first die 120 may be, for example, an ASIC (Application-Specific Integrated Circuit). In some embodiments, the first die 120 may be used to perform logic applications. However, it construes no limitation in the disclosure. Other suitable active devices may also be utilized as the first die 120.
Referring to
The spacer 130 may include a second circuit carrier 132 with conductive pads on the surface opposite to the first die 120 for the subsequent bonding process. It should be noted that other suitable forms of the spacer 130 may be utilized and the details will be described later in other embodiments. In some embodiments, the spacer 130 may serve as a dummy chip for performing the subsequent wire bonding process and/or providing a spacer function to prevent damage to the first die 120. The size and the thickness of the spacer 130 may construe no limitation to the unit sizes and unit thicknesses of the first die 120. In some embodiment, the spacer 130 may be a semiconductor carrier having a similar shape or appearance as that of a chip while not having active devices formed therein. In some other embodiments, the spacer 130 and the first die 120 may be mechanically coupled but electrically isolated from each other when the entire manufacturing process is completed.
Referring to
In some embodiments, the wire bonder may include an automated device that welds the conductive wires 150. For instance, each of the conductive wires 150 is fed through a bonding tool such as a capillary (not illustrated) that applies heat, ultrasonic energy, pressure, or the combination thereof to bond each of the conductive wires 150 between the first circuit carrier 110 and the spacer 130. In some embodiments, each of the first welding segments 152 of the conductive wires 150 may include a welding portion 152a bonded to the first circuit carrier 110 and a wire portion 152b coupled to the welding portion 152a. For example, the welding portion 152a of each of the first welding segments 152 may be formed through ball bond, wedge bond, or other suitable bond depending on the design requirement. After bonding the welding portion 152a to the top surface S1 of the first circuit carrier 110, the wire portion 152b of each of the first welding segments 152 coupled to the welding portion 152a may be delivered out by the bonding tool of the wire bonder. For instance, the bonding tool of the wire bonder may move upwards from the first circuit carrier 110 to form the wire portion 152b in a vertical manner.
Next, the bonding tool may move in a direction upward away from the first circuit carrier 110 and towards the spacer 130 to form the sacrificial segment 154. An arcing shape in the sacrificial segment 154 of each of the conductive wires 150 may be formed. In addition, a loop height H1 of each of the conductive wires 150 may be a distance between the peak of the arcing shape of the sacrificial segment 154 and the bottom end of the welding portion 152a of the first welding segment 152 coupled to the first circuit carrier 110. The loop height H1 may depend on the type of the wire bonder and/or the design requirement, which is not limited thereto. Subsequently, the bonding tool of the wire bonder may be positioned at the conductive pads of the second circuit carrier 132 of the spacer 130 and a tail bond of each of the second welding segment 156 of the conductive wires 150 may be formed to bond the second circuit carrier 132. As such, the wire bonding process on, the first circuit carrier 110 and the second circuit carrier 132 of the spacer 130 is completed.
In some embodiments, an angle θ1 between the first welding segment 152 of each of the conductive wires 150 and the first circuit carrier 110 is greater than or equal to an angle θ2 between the second welding segment 156 of each of the conductive wires 150 and the spacer 130. The angle θ1 may depend on the types of the wire bonding and/or the design requirement. For example, a ball bonder welds a conductive ball on the conductive pads 114a of the first circuit carrier 110 to a contact with each of the conductive wire 150 extending away from the conductive ball at right angle. However, for the wedge bonder, in some embodiments, it presses the side of the conductive wires 150 against the contact so the angle θ1 between each of the first welding segments 152 of the conductive wires 150 and the top surface S1 of the first circuit carrier 110 may be less than 90 degree, but substantially close to 90 degree. In some other embodiments, each of the second welding segments 156 of the conductive wires 150 may be perpendicular to the spacer 130. As such, the angle θ2 may be 90 degree or substantially close to 90 degree.
Referring to
Referring to
In some embodiments, the encapsulant 160 may be removed by a grinding process. Moreover, the grinding process may be mechanical grinding, chemical mechanical polishing (CMP), etching, or other suitable method, which is not limited thereto. Moreover, after reducing the thickness T1 of the encapsulant 160, a top surface of the wire portion 152b of each of the first welding segment 152 and a top surface of each of the second welding portion 156 are exposed from the encapsulant 160. In some embodiments, after reducing the thickness T1 of the encapsulant 160, the top surface of the wire portion 152b of each of the first welding segment 152, the top surface of each of the second welding portion 156, and a top surface of the encapsulant 160 may be coplanar. Wherein, the top surface of the encapsulant 160 may be the surface farthest from the first circuit carrier 110. In other word, after reducing the thickness T1 of the encapsulant 160, a height H2 of each of the first welding segments 152 is equal to the thickness T2 of the encapsulant 160.
In one embodiment, after reducing the thickness T1 of the encapsulant 160, the top surface of the wire portion 152b may be used for further electrical connection with the first circuit carrier 110. The top surface of each of the second welding portion 156 may be dummy paths. In some other embodiments, after reducing the thickness T1 of the encapsulant 160, both of the top surface of the wire portion 152b of each of the first welding segment 152 and the top surface of each of the second welding portion 156 may serve as the conductive path for further electrical connection according to the design requirement. In addition, it should be noted that the thickness reducing process as shown in
Referring to
In one embodiment, the second package structure 200 may include a central region CR and a peripheral region PR surrounding the central region CR. For instance, the second die 202 may be located in the central region CR and the conductive terminals 204 may be disposed in the peripheral region PR. Moreover, when the second package structure 200 is stacked on the first package structure 100, the second die 202 in the central region CR of the second package structure 200 may be disposed corresponding to the first die 120 of the first package structure 100. In addition, each of the conductive terminals 204 in the peripheral region PR of the second package structure 200 may be disposed on one of the first welding segments 152 of the conductive wires 150 exposed by the encapsulant 160 of the first package structure 100, respectively. In one embodiment, the second die 202 in the central region CR of the second package structure 200 may be staggered from the first die 120 of the first package structure 100. In another embodiment, the conductive terminals 204 may be disposed in both of the central region CR and the peripheral region PR for electrical connection to the first package structure 100. In some embodiments, a thermal conductive layer (not illustrated) may be disposed in thermal contact or thermally coupled between the second package structure 200 and the first package structure 100 for enhancing the heat dissipation efficiency. As such, the stress applied onto the POP structure 10 during the subsequent reliability tests may be shared by the thermal conductive layer for increasing the reliability of the POP structure 10.
Since the first welding segments 152 may serve as the electrical connection path between the first package structure 100 and the second package structure 200, an additional interposer for electrically connecting between the first package structure 100 and the second package structure 200 can be omitted. Thereby the overall thickness of the POP structure 10 and the manufacturing costs may be reduced.
Referring to
Moreover, a thermal adhesive layer 340 may be disposed between the first die 120 and the spacer 330. In some embodiments, the thermal adhesive layer 340 may include die attach compositions possessing a high thermal conductivity such as silver, silver coated or aluminium nitride particles formed by such as spin coating, inject printing or other suitable methods. However, a material and forming processes of the thermal adhesive layer 340 construe no limitation in the disclosure. The thermal adhesive layer 340 may serve as a direct thermal conductivity path from the first die 120 to the spacer 330 and further enhance the heat dissipation efficiency during the heat generated from the first die 120. Furthermore, the thermal adhesive layer 340 may provide a structural support without the need for mechanical clamping between the first die 120 and the spacer 330.
Referring to
In addition, each of the welding segments 352 of the conductive wires 350 may include a welding portion 352a coupled to the first circuit carrier 110 and a wire portion 352b connected to the welding portion 352a. For example, the welding portion 352a of each of the welding segments 352 may be formed through ball bond, wedge bond or other suitable bond depending on the design requirement. It should be noted that the forming process of the welding portions 352a and the wire portions 352b of the welding segments 352 may be similar to the forming process of the welding portions 152a and the wire portions 152b of the first welding segments 152 illustrated in
Each of the sacrificial segments 354 of the conductive wires 350 may include an arc-shape portion 354a and a tail portion 354b. The forming process of the sacrificial segments 354 may be similar to the forming process of the sacrificial segments 154 and the second welding segments 156 of the conductive wires 150. The detailed descriptions are omitted herein. In addition, a loop height H3 of each of the conductive wires 350 may be a distance between the peak of the arc-shape portion 354a of the sacrificial segment 354 and the bottom end of the welding portion 352a of the first welding segment 352 coupled to the first circuit carrier 110. It should be noted that the loop height H3 depends on the types of the wire bonder and/or the design requirement, which is not limited thereto.
In some embodiments, an angle θ3 between the welding segment 352 of each of the conductive wires 350 and the first circuit carrier 110 is greater than an angle θ4 between the sacrificial segment 354 of each of conductive wires 350 and the spacer 330. Similar to the embodiment illustrated in
Referring to
In the present embodiment, the sacrificial segments 354 of the conductive wires 350 are removed. For instance, the thickness T1 of the encapsulant 160 is reduced to a thickness T3 as shown in
Referring to
Based on the above, the spacer disposed on the die is conducive to the forming process of the conductive wires. Moreover, since at least a portion of the conductive wires are removed during reducing the thickness of the encapsulant, the rest portion of the conductive wires remaining in the encapsulant may be used as the electrical connecting path between the first package structure and the second package structure. As a result, it is unnecessary to dispose additional interposer between the first package structure and the second package structure for electrical connection. Therefore, not only the overall thickness of the POP structure but the manufacturing cost may be reduced. In addition, the spacer may be exposed from the encapsulant so the spacer may serve as a heat-dissipating element after reducing the thickness of the encapsulant. As such, it may open the possibility to various POP structure designs.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.
Claims
1. A manufacturing method of a package-on-package (POP) structure, comprising:
- bonding a die on a first circuit carrier;
- disposing a spacer on the die;
- connecting the spacer and the first circuit carrier through a plurality of conductive wires;
- forming an encapsulant to encapsulate the die, the spacer and the conductive wires;
- reducing a thickness of the encapsulant until at least a portion of each of the conductive wires are removed to form a first package structure; and
- stacking a second package structure on the first package structure, wherein the second package structure is electrically connected to the conductive wires.
2. The manufacturing method of a POP structure according to claim 1, wherein the die is electrically connected to the first circuit carrier through flip-chip bonding.
3. The manufacturing method of a POP structure according to claim 1, wherein the spacer is bonded to the die through an adhesive layer.
4. The manufacturing method of a POP structure according to claim 1, wherein the conductive wires are formed through a wire bonder.
5. The manufacturing method of a POP structure according to claim 1, wherein the spacer comprises a second circuit carrier, the conductive wires are connected between the second circuit carrier and the first circuit canier before reducing the thickness of the encapsulant.
6. The manufacturing method of a POP structure according to claim 5, wherein each of the conductive wires comprises a first welding segment connected to the first circuit carrier and a second welding segment connected to the spacer before reducing the thickness of the encapsulant, the conductive wires are connected from the first circuit carrier through the first welding segments to the spacer through the second welding segments.
7. The manufacturing method of a POP structure according to claim 6, wherein an angle between the first welding segment of each of the conductive wires and the first circuit carrier is greater than an angle between the second welding segment of each of the conductive wires and the spacer before reducing the thickness of the encapsulant.
8. The manufacturing method of a POP structure according to claim 6, wherein each of the conductive wires further comprises a sacrificial segment connecting between the first welding segment and the second welding segment before reducing the thickness of the encapsulant, when reducing the thickness of the encapsulant, the sacrificial segments of the conductive wires are removed.
9. The manufacturing method of a POP structure according to claim 8, wherein after reducing the thickness of the encapsulant, a portion of each of the first welding segments of the conductive wires and a portion of each of the second welding segments of the conductive wires are exposed by the encapsulant.
10. The manufacturing method of a POP structure according to claim 8, wherein after the sacrificial segments of the conductive wires are removed, the spacer is electrically floated.
11. The manufacturing method of a POP structure according to claim 8, wherein the second package structure comprises a plurality of conductive terminals, each of the conductive terminals of the second package structure is disposed on one of the first welding segments of the conductive wires exposed by the encapsulant respectively.
12. The manufacturing method of a POP structure according to claim 1, wherein the spacer comprises a conductive plate.
13. The manufacturing method of a POP structure according to claim 12, wherein the spacer is bonded to the die through a thermal adhesive layer.
14. The manufacturing method of a POP structure according to claim 12, wherein after reducing the thickness of the encapsulant, a surface of the spacer is exposed from the encapsulant.
15. The manufacturing method of a POP structure according to claim 12, wherein each of the conductive wires comprises a welding segment connected to the first circuit carrier and a sacrificial segment connected between the welding segment and the spacer before reducing the thickness of the encapsulant, the conductive wires are connected from the first circuit carrier through the welding segment to the spacer through the sacrificial segment.
16. The manufacturing method of a POP structure according to claim 15, wherein an angle between the welding segment of each of the conductive wires and the first circuit carrier is greater than an angle between the sacrificial segment of each of the conductive wires and the spacer before reducing the thickness of the encapsulant.
17. The manufacturing method of a POP structure according to claim 15, wherein when reducing the thickness of the encapsulant, the sacrificial segments of the conductive wires are removed.
18. The manufacturing method of a POP structure according to claim 15, wherein after reducing the thickness of the encapsulant, a portion of each of the welding segments of the conductive wires are exposed by the encapsulant.
19. The manufacturing method of a POP structure according to claim 15, wherein after the sacrificial segments of the conductive wires are removed, the spacer is electrically floated.
20. The manufacturing method of a POP structure according to claim 15, wherein the second package structure comprises a plurality of conductive terminals, each of the conductive terminals of the second package structure is disposed on one of the welding segments exposed by the encapsulant respectively.
Type: Application
Filed: Sep 28, 2017
Publication Date: Apr 26, 2018
Applicant: Powertech Technology Inc. (Hsinchu County)
Inventors: Chi-An Wang (Hsinchu County), Hung-Hsin Hsu (Hsinchu County), Yuan-Fu Lan (Hsinchu County), Hsien-Wen Hsu (Hsinchu County)
Application Number: 15/717,953