CN219329260U - Packaging structure - Google Patents

Abstract

The utility model relates to a packaging structure, which includes a circuit layer. The circuit layer includes a dielectric layer and a pad, the pad is embedded in the dielectric layer, and the pad is exposed from the top surface of the dielectric layer, and the top surface of the pad is aligned with the top surface of the dielectric layer. The package structure also includes a metal layer disposed over the interface between the pad and the dielectric layer. The above technical solution of the present application can at least avoid the problem of delamination at the interface between the dielectric layer and the pad by disposing the metal layer above the interface between the dielectric layer and the pad.

Description

Package structure

technical field

The utility model relates to the technical field of semiconductors, in particular to a packaging structure.

Background technique

Referring to FIG. 1A to FIG. 1D, the current chip last process may include the following steps: Referring to FIG. 1A, fan-out (Fan-out) is formed on a redistribution layer (RDL, Redistribution Layer) carrier 10 Redistribution layer 20; as shown in FIG. 1B, connect electronic device 32 on redistribution layer 20 and use molding compound 36 to mold electronic device 32, and set carrier 40 above molding compound 36 and electronic device 32; refer to FIG. 1C As shown, the redistribution layer carrier 10 in FIG. 1B is removed, and the dielectric layer 22 and the pad 24 of the redistribution layer 20 are exposed; as shown in FIG. 1D, the structure shown in FIG. Solder balls 50 are formed on the exposed pads 24 .

In the above-mentioned current chip post-assembly process, after removing the redistribution layer carrier 10 connecting the pads 24 in FIG. And do not cover each other (see Figure 1D), so the following two problems may be faced:

(1) As shown in FIG. 1E , the surface of the dielectric layer 22 is flush with the bonding surface of the pad 24 , and there is a risk of delamination 55 at the interface between the dielectric layer 22 and the pad 24 due to thermal stress. .

(2) As shown in FIG. 1F , the bonding surface of the pad 24 is a non-bowl-shaped structure. During the reflow process after the ball drop (ball drop), the solder ball 50 may slide, causing the solder ball 50 to not be connected to the pad 24 On, or may cause solder ball 50 bridge (ballbridge). The existing solder ball formation yield is estimated to be only 80%, and the reliability risk is relatively high.

As shown in FIG. 2, although the above problem can be solved by using another layer of dielectric layer 62 to cover the interface between the dielectric layer 22 of the redistribution layer 20 and the pad 24 to solve the delamination problem shown in FIG. 1E, and can Opening holes on the dielectric layer 22 to expose the pads 24 to form a bowl-shaped structure can solve the risk of solder ball sliding as shown in FIG. 1F , but the dielectric layer 62 will cover part of the pads 24 and affect electrical performance.

Utility model content

In view of the above problems in the related art, the utility model proposes a packaging structure, which can at least solve the delamination problem at the interface between the pad and the dielectric layer.

According to an embodiment of the present invention, a packaging structure is provided. The encapsulation structure includes a wiring layer. The circuit layer includes a dielectric layer and a pad, the pad is embedded in the dielectric layer, and the pad is exposed from the top surface of the dielectric layer, and the top surface of the pad is aligned with the top surface of the dielectric layer. The package structure also includes a metal layer disposed over the interface between the pad and the dielectric layer.

In some embodiments, the package structure further includes an electrical connector, the metal layer has an opening exposing the pad, and the electrical connector is connected to the pad through the opening so that the electrical connector is located above the pad.

In some embodiments, the metal layer is a ring structure and exposes a portion of the upper surface of the pad.

In some embodiments, the package structure further includes an electrical connector contacting the metal layer and a portion of the upper surface of the pad.

In some embodiments, the package structure further includes a seed layer located between the interface and the metal layer.

In some embodiments, a portion of the lower surface of the metal layer contacts the top surface of the dielectric layer and another portion of the lower surface of the metal layer contacts the upper surface of the pad.

In some embodiments, the upper surface of the pad is a first upper surface, the pad further has a second upper surface lower than the first upper surface, and the metal layer extends from the first upper surface to the second upper surface.

In some embodiments, the first upper surface surrounds the second upper surface, and the metal layer exposes a portion of the second upper surface of the pad.

In some embodiments, the package structure further includes an electrical connector contacting the metal layer and a portion of the second upper surface of the bonding pad.

In some embodiments, the electrical connections are separated from the top surface of the dielectric layer by the metal layer.

The above-mentioned packaging structure of the present application can avoid the delamination problem at the interface between the dielectric layer and the pad by arranging the metal layer above the interface between the dielectric layer and the pad; the electrical connector can be limited to the metal layer layer and pad, thus reducing the positional offset of the electrical connector relative to the pad, which can solve the risk of slippage when the upper surface of the pad is flush with the top surface of the dielectric layer. In addition, compared with the existing method of using a dielectric layer to cover part of the pads to solve the delamination problem and the risk of sliding that will affect the electrical performance, the packaging structure of the present application can avoid adverse effects on the electrical performance.

Description of drawings

Aspects of the present invention are best understood from the following detailed description when read with the accompanying drawings. It should be noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or decreased for clarity of discussion.

1A to 1D are schematic cross-sectional views of various stages of forming a packaging structure in the prior art.

FIG. 1E and FIG. 1F are structural schematic diagrams of delamination risk and solder ball sliding risk generated in the prior art, respectively.

FIG. 2 is a schematic cross-sectional view of another package structure in the prior art.

FIG. 3A is a schematic cross-sectional view of a package structure according to an embodiment of the present application.

FIG. 3B is a schematic top view of the metal layer shown in FIG. 3A .

FIG. 4 is a schematic cross-sectional view of a package structure according to another embodiment of the present application.

FIG. 5 is a schematic cross-sectional view of a package structure according to another embodiment of the present application.

6A to 6E are schematic cross-sectional views of various stages of forming a package structure according to an embodiment of the present application.

specific embodiment

The following disclosure provides many different embodiments or examples for implementing different features of the presented subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are just examples and are not intended to limit the utility model. For example, in the following description, forming a first component over or on a second component may include embodiments in which the first component and the second component are in direct contact, or may include forming an additional component between the first component and the second component An embodiment such that the first part and the second part may not be in direct contact. Also, the present invention may repeat reference numerals and/or letters in various instances. This repetition is for brevity and clarity only and does not in itself indicate a relationship between the various embodiments and/or configurations discussed.

Embodiments according to the present application provide a packaging structure. FIG. 3A is a schematic cross-sectional view of a package structure 100 according to an embodiment of the present application. Referring to FIG. 3A , the packaging structure 100 includes a wiring layer 120 . In some embodiments, the wiring layer 120 is a redistribution layer. The wiring layer 120 may include a dielectric layer 121 and a pad 126 embedded in the dielectric layer 121 . The wiring layer 120 may further include another dielectric layer 122 , 123 , 124 located under the dielectric layer 121 . FIG. 3A shows that the circuit layer 120 includes four dielectric layers 121 , 122 , 123 , and 124 stacked in total, but may also include other numbers of dielectric layers. The dielectric layer 121 is the uppermost dielectric layer among the dielectric layers 121 , 122 , 123 , 124 of the wiring layer 120 .

The upper surface 126u of the pad 126 is exposed by the top surface 121t of the dielectric layer 121 . The upper surface 126u of the pad 126 is aligned with, ie, coplanar with, the top surface 121t of the dielectric layer 121 . There is an interface 125 between the pad 126 and the dielectric layer 121 . The package structure 100 also includes a metal layer 130 disposed over the interface 125 between the pad 126 and the dielectric layer 121 . By disposing the metal layer 130 over the interface 125 between the dielectric layer 121 and the pad 126, delamination problems at the interface 125 between the dielectric layer 121 and the pad 126 can be avoided. Since the delamination problem is avoided, all sides of the pad 126 can be in contact with the dielectric layer 121 to form the interface 125 .

Metal layer 130 extends from top surface 121 t of dielectric layer 121 across interface 125 to upper surface 126 u of pad 126 . Thus, a portion 130b1 of the lower surface 130b of the metal layer 130 contacts the top surface 121t of the dielectric layer 121 , and another portion 130b2 of the lower surface 130b of the metal layer 130 contacts the upper surface 126u of the pad 126 . The package structure 100 also includes electrical connections 150 to the pads 126 . Electrical connections 150 are located on pads 126 and metal layer 130 . In some embodiments, the electrical connector 150 may be a component for electrical connection such as a solder ball. The electrical connector 150 is not in contact with the dielectric layer 121 , and the electrical connector 150 is separated from the top surface 121 t of the dielectric layer 121 by the metal layer 130 .

Metal layer 130 may be formed of any suitable metal material. Materials that can form a eutectic with the electrical connector 150 can be used to form the metal layer 130 . In some embodiments, the material of the metal layer 130 may be copper, that is, the metal layer 130 is a copper layer. In other embodiments, the material of the metal layer 130 may include nickel and gold. In such an embodiment, the metal layer 130 includes a nickel layer formed by an electroless nickel gold (ENIG) process and a gold layer on the nickel layer. In some embodiments, the metal layer 130 and the bonding pad 126 may be formed of the same material, for example, the metal layer 130 and the bonding pad 126 may be made of copper. In other embodiments, the metal layer 130 and the bonding pad 126 may be formed of different materials.

FIG. 3B is a schematic top view of the metal layer 130 shown in FIG. 3A . For simplicity, the top view shown in FIG. 3B corresponds to the top view when no electrical connection 150 (see FIG. 3A ) is formed on the metal layer 130 and pad 126 . Referring to FIG. 3B , the metal layer 130 is a ring structure. As shown in FIG. 3A and FIG. 3B , the metal layer 130 of the ring structure may have an opening 132 exposing the pad 126 , and the opening 132 exposes a part of the upper surface 126 u of the pad 126 . The electrical connector 150 contacts the metal layer 130 and a portion of the upper surface 126 u of the pad 126 exposed by the metal layer 130 . Electrical connection 150 is connected to pad 126 through opening 132 defined by metal layer 130 such that electrical connection 150 is located over pad 126 .

According to an embodiment of the present application, the metal layer 130 is configured to reduce positional deviation of the electrical connector 150 . Since the metal layer 130 protrudes from the upper surface 126 u of the pad 126 and the top surface 121 t of the dielectric layer 121 , the metal layer 130 and the pad 126 can be configured into a bowl-shaped structure with high edges and low center. Since the metal layer 130 and the pad 126 form a bowl-shaped structure with high edges and a low center, when the electrical connector 150 is formed on the pad 126, the electrical connector 150 can be limited to the metal layer 130 and the pad 126. , so the risk of sliding when the upper surface 126u of the pad 126 is flush with the top surface 121t of the dielectric layer can be solved, and the positional deviation of the electrical connector 150 relative to the pad 126 can be reduced without increasing the thickness of the circuit layer 120 The process yield is improved and the structural reliability is increased. The solder ball formation yield can be higher than 99.9%, and the reliability detection failure rate can reach close to 0%. In addition, compared with the way shown in FIG. 2 by using the dielectric layer 62 to cover part of the pad 24 to solve the problem of delamination and the risk of sliding will affect the electrical performance, the embodiment of the present application covers the part of the pad 126 and The conductive metal layer 130 can avoid adverse effects on electrical performance.

In addition, the side of the circuit layer 120 opposite to the electrical connector 150 may be connected to the electronic device 110 . The electronic device 110 may be, for example, a chip or the like. Electronic device 110 is encapsulated by molding compound 115 . The electronic device 110 is connected to pads 129 exposed by the lowermost dielectric layer 124 in the wiring layer 120 .

Fig. 4 is a schematic cross-sectional view of a package structure 100' according to another embodiment of the present application. Referring to FIG. 4 , a seed layer 127 may be disposed between the interface 125 between the pad 126 and the dielectric layer 121 and the metal layer 130 . Sides of the seed layer 127 may be vertically aligned with corresponding sides of the metal layer 130 .

FIG. 5 is a schematic cross-sectional view of a package structure 200 according to another embodiment of the present application. In the package structure 200 shown in FIG. 5 , the upper surface 126u of the pad 126 includes a first upper surface 126u1 and a second upper surface 126u2 lower than the first upper surface 126u1 . The first upper surface 126u1 corresponds to the edge region of the bonding pad 126 , and the second upper surface 126u2 corresponds to the central region of the bonding pad 126 . The first upper surface 126u1 surrounds the second upper surface 126u2. The metal layer 230 covers the first upper surface 126u1 of the pad 126 . The metal layer 230 exposes a portion of the second upper surface 126u2 of the pad 126 . The electrical connector 150 contacts the metal layer 230 and a portion of the second upper surface 126u2 of the pad 126 exposed by the metal layer 230 .

The metal layer 230 extends from the first upper surface 126u1 to the second upper surface 126u2. A groove may be formed on the pad 126 by removing a portion of the pad 126 , thereby defining a first upper surface 126u1 and a second upper surface 126u2 of the pad 126 . The metal layer 230 extends from the top surface 121t of the dielectric layer 121 across the interface 125 between the dielectric layer 121 and the bonding pad 126, then extends across the first upper surface 126u1 of the bonding pad 126, and then extends down to the bonding pad 126. on the second upper surface 126u2. The electrical connector 150 is not in contact with the dielectric layer 121 , and the electrical connector 150 is separated from the top surface 121 t of the dielectric layer 121 by the metal layer 230 .

The shape of the metal layer 230 shown in FIG. 5 can increase the contact area between the metal layer 230 and the pad 126, and can fasten the dielectric layer 121 and the pad 126 together, further preventing separation between the dielectric layer 121 and the pad 126. In addition, the shape of the metal layer 230 shown in FIG. 5 can also increase the contact area between the metal layer 230 and the electrical connector 150 to ensure the fixing effect of the electrical connector 150 .

Other aspects of the package structure 200 shown in FIG. 5 may be similar to those described above with reference to FIG. 3A and FIG. 4 , and will not be repeated here.

6A to 6E are schematic cross-sectional views of various stages of forming a package structure according to an embodiment of the present application. Referring first to FIG. 6A , a circuit layer carrier 610 and a circuit layer 120 formed on the circuit layer carrier 610 are provided. In this embodiment, the circuit layer 120 may include four dielectric layers 121 , 122 , 123 , 124 formed in sequence. At this stage, pads 126 are embedded in the dielectric layer 121 in contact with the circuit layer carrier 610 , and the pads 126 are exposed by the dielectric layer 121 and are in contact with the circuit layer carrier 610 . A pad 129 is disposed in the dielectric layer 124 on the side opposite to the circuit layer carrier 610 of the circuit layer 120 , and the pad 129 is exposed by the dielectric layer 124 .

Referring to FIG. 6B , for example, the electronic device 110 is connected to the pad 129 of the circuit layer 120 by using an SMT (Surface Mounted Technology, surface mount technology) process. The electronic device 110 is molded using a molding compound 115 . The molding compound 115 may be flushed with the surface of the electronic device 110 through a lapping process. Then, a carrier 620 is attached over the molding compound 115 and the electronic device 110 .

Referring to FIG. 6C , the circuit layer carrier 610 in FIG. 6B is removed to expose the dielectric layer 121 and the pad 126 of the circuit layer 120 .

Referring to FIG. 6D, the structure shown in FIG. 6C is inverted. At this time, the top surface 121t of the dielectric layer 121 is flush with the top surface 126u of the pad 126 . There is an interface 125 between the dielectric layer 121 and the bonding pad 126 . A metal layer 130 disposed over interface 125 is then formed. The metal layer 130 may be similar to the metal layer 130 described above with reference to FIGS. 3A to 3B . In some embodiments, as described with reference to FIG. 4 , before forming the metal layer 130 , the seed layer 127 may be formed first, and then the metal layer 130 may be formed on the seed layer 127 .

Referring to FIG. 6E , solder balls 150 are formed on the metal layer 130 and on the pads 126 . Since the metal layer 130 is provided above the interface 125, the electrical connector 150 can be limited on the pad 126 when the solder ball 150 is formed, the positional deviation of the electrical connector 150 relative to the pad 126 is reduced, and the soldering problem can be solved. Risk of slippage when the upper surface 126u of the disk 126 is flush with the top surface 121t of the dielectric layer 121 . In some embodiments, after the solder balls 150 are formed, the carrier 620 can be removed to obtain the package structure 100 as shown in FIG. 3A .

The upper surface 160u of the pad 126 formed in FIG. 6E is a flat surface. In another embodiment, after the stage shown in FIG. 6C , a part of the pad 126 may be removed to form a groove on the upper surface of the pad 126, and then a metal layer 230 extending into the groove may be formed to obtain The packaging structure 200 shown in FIG. 5 .

The foregoing summarizes features of several embodiments so that those skilled in the art may better understand the various aspects of the present disclosure. Those skilled in the art should understand that it is easy to use the present invention as a basis to design or modify other processes and structures to achieve the same purpose and/or realize the same advantages as the embodiments introduced in the present invention. Those skilled in the art should also realize that these equivalent structures do not depart from the spirit and scope of the present invention, and that various changes, substitutions and changes can be made without departing from the spirit and scope of the present invention.

Claims (10)

1. A package structure, comprising:

a wiring layer, the wiring layer comprising:

a dielectric layer;

a pad buried within the dielectric layer and exposed by a top surface of the dielectric layer, an upper surface of the pad being aligned with the top surface of the dielectric layer;

and a metal layer disposed over an interface between the pad and the dielectric layer.

2. The package structure of claim 1, further comprising:

an electrical connector, the metal layer having an opening exposing the pad, the electrical connector being connected to the pad through the opening such that the electrical connector is located over the pad.

3. The package structure of claim 1, wherein,

the metal layer is of a ring-shaped structure and exposes a portion of the upper surface of the bonding pad.

4. The package structure of claim 3, further comprising:

an electrical connection contacting the metal layer and the portion of the upper surface of the pad.

5. The package structure of claim 1, further comprising:

a seed layer located between the interface and the metal layer.

6. The package structure of claim 1, wherein,

a portion of a lower surface of the metal layer contacts the top surface of the dielectric layer and another portion of the lower surface of the metal layer contacts the upper surface of the pad.

7. The package structure of claim 1, wherein,

the upper surface of the pad is a first upper surface, the pad further has a second upper surface lower than the first upper surface, and the metal layer extends from the first upper surface onto the second upper surface.

8. The package structure of claim 7, wherein,

the first upper surface surrounds the second upper surface, and the metal layer exposes a portion of the second upper surface of the pad.

9. The package structure of claim 8, further comprising:

an electrical connection contacting the metal layer and the portion of the second upper surface of the pad.

10. The package structure of claim 2, wherein,

the electrical connection is separated from the top surface of the dielectric layer by the metal layer.

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