Package structure and method of forming the same

Abstract

A package structure includes a substrate, a circuit layer above the substrate, a die between the substrate and the circuit layer, a first conductive structure connected to the circuit layer, and a second conductive structure electrically connecting the first conductive structure to the die, wherein the second conductive structure has a bent portion.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically, to a packaging structure and a method for forming the same. Background Technology

[0002] With the development and increasing demands of smart mobile devices, functions are becoming more and more diverse, making IC (integrated circuit) integration increasingly important. To achieve smaller package sizes, embedding active and passive components into the substrate is a major approach. Embedding components into the substrate can effectively reduce electrical transmission paths, further reducing power consumption, so as to integrate ICs with various functions into a small package.

[0003] Currently, after embedding active and passive components into the substrate, reference Figure 1A As shown, laser drilling is required to form the pads 15 connected to the die 12. When the embedded component die 12 is a high-IO component, in addition to the limitation on the diameter of the laser (accompanied by high cost), it is also difficult to directly form the opening 16 in the high-IO region due to the error value of the laser drilling accuracy. For example, as Figure 1B Compared to standard drilling, this results in an over-drilled opening. Summary of the Invention

[0004] To address the aforementioned problems in related technologies, this invention proposes a packaging structure and its formation method.

[0005] The technical solution of this invention is implemented as follows:

[0006] According to one aspect of the present invention, a packaging structure is provided, comprising: a substrate; a circuit layer located above the substrate; a die located between the substrate and the circuit layer; a first conductive structure connected to the circuit layer; and a second conductive structure electrically connecting the first conductive structure to the die, wherein the second conductive structure has a bent portion.

[0007] In some embodiments, the first conductive structure is a through hole.

[0008] In some embodiments, the first conductive structure penetrates the circuit layer and is electrically connected to the second conductive structure.

[0009] In some embodiments, the packaging structure further includes an adhesive layer located between the substrate and the circuit layer and surrounding the second conductive structure.

[0010] In some embodiments, the encapsulation structure further includes an isolation structure, wherein a first side of the first conductive structure is connected to a second conductive structure, and the isolation structure is located on a second side of the first conductive structure opposite to the first side and is in contact with the second side.

[0011] In some embodiments, the packaging structure further includes a third conductive structure connected to the substrate, wherein the second conductive structure and the third conductive structure are located on opposite sides of the isolation structure and are electrically isolated by the isolation structure.

[0012] In some embodiments, the die includes an active device die and a passive device die.

[0013] In some embodiments, the second conductive structure is a pad electrically connected to the die.

[0014] In some embodiments, the substrate has patterned openings, wherein a second conductive structure is above the openings and extends across them.

[0015] In some embodiments, the substrate is a lead frame.

[0016] According to another aspect of the present invention, a method for forming a package structure is provided, comprising: disposing a die on a substrate and connecting the die to the substrate via leads; stacking a circuit layer on top of the substrate via an adhesive layer; forming a through-hole through the circuit layer and leads using a laser drilling process; and forming a conductive structure within the through-hole.

[0017] In some embodiments, after connecting the die to the substrate via leads, the method further includes: forming an adhesive layer covering the leads; forming an opening through the adhesive layer and through the leads; and forming an isolation structure in the opening.

[0018] In some embodiments, the laser drilling process for forming through holes also removes portions of the isolation structure.

[0019] In some embodiments, the isolation structure is in contact with the substrate, and the conductive structure is spaced apart from the substrate by an adhesive layer.

[0020] In some embodiments, after forming the conductive structure, the method further includes forming solder balls on the conductive structure.

[0021] In some embodiments, forming a conductive structure within a via includes: forming a seed layer within the via; and filling the seed layer with a conductive metal material.

[0022] In some embodiments, the substrate has patterned openings, and leads connecting the die and the substrate cross over the openings.

[0023] In some embodiments, the leads include a plurality of leads electrically connected to pads on the die.

[0024] In some embodiments, the substrate is a lead frame substrate.

[0025] In some embodiments, the die includes an active device die and a passive device die. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1A and Figure 1B This is a schematic diagram of the current square-shaped packaging structure.

[0028] Figure 2A and Figure 2B These are, respectively, a side view and a top view of the packaging structure according to an embodiment of the present invention.

[0029] Figures 3A to 3R This is a schematic diagram illustrating the various stages of forming a packaging structure according to an embodiment of the present invention.

[0030] Figures 4 to 6 This is a schematic diagram of another embodiment of the packaging structure according to an embodiment of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0032] like Figure 2A The diagram illustrates a packaging structure according to an embodiment of the present invention. The packaging structure includes a substrate 202 and a circuit layer 204 located above the substrate 202. The circuit layer 204 may include an RDL (redistribution line). A die 205 is disposed between the substrate 202 and the circuit layer 204. A first conductive structure 206 and a second conductive structure 208 are also provided to connect the die 205 to the circuit layer 204. The first conductive structure 206 is electrically connected to the circuit layer 204. The first conductive structure 206 may be a via. The first conductive structure 206 penetrates the circuit layer 204 and is electrically connected to the second conductive structure 208. The second conductive structure 208 electrically connects the first conductive structure 206 to the die 205. The second conductive structure 208 is a conductive structure with a bent portion. In the illustrated embodiment, the second conductive structure 208 is a pad 209 electrically connected to the die 205. The second conductive structure 208 may be part of a bonding wire 210 connected to the pad 209 of the die 205. Figure 2BAs shown, this invention employs a fanout-like concept, fanning out the high I / O region to the surrounding area of ​​the die 205 via a second conductive structure 208. The second conductive structure 208, for example, being part of a lead 210, extends the connection to the pads 209 of the die 205, and a laser is used to drill holes in the circuit layer 204 and connect them to the second conductive structure 208. Figure 2A and Figure 2B It is known that any path along the second conductive structure 208 can serve as a connection point for laser apertures, thus increasing the effective path and area for connection with the die 205. Furthermore, a larger diameter laser can be used to form the aperture connected to the second conductive structure 208, fanning out the high I / O region to the surrounding area of ​​the die 205, improving the aperture accuracy error of current methods and effectively reducing costs.

[0033] Continue to refer to Figure 2A As shown, adhesive layer 212 is located between substrate 202 and circuit layer 204 and surrounds the second conductive structure 208. The material of adhesive layer 212 may include NCP, NCF, ACP, ACF, PI, epoxy, resin, pp, ABF, and glue. In some embodiments, the thickness of adhesive layer 212 may range from 50 micrometers to 200 micrometers. In the illustrated embodiment, circuit layer 204 has three layers. In other embodiments, circuit layer 204 may have a single-layer circuit layer, or may include any other number of circuit layers.

[0034] An isolation structure 215 is disposed between the circuit layer 204 and the adhesive layer 212. A first side of the first conductive structure 206 is connected to the second conductive structure 208, and the isolation structure 215 is located on a second side of the first conductive structure 206 opposite to the first side and in contact with the second side. In some embodiments, the material of the isolation structure 215 may include organic materials, such as PA, PI, Epoxy, PBO, FR4, pp, and ABF. In some embodiments, the material of the isolation structure 215 may include inorganic materials, such as silicon, glass, ceramics, and oxides (e.g., SiO2). x SiN x TaO x In some embodiments, the isolation structure 215 may have embedded filler to improve the rigidity of the isolation structure 215.

[0035] The packaging structure also includes a third conductive structure 207 connected to the substrate 202. The second conductive structure 208 and the third conductive structure 207 are located on opposite sides of the isolation structure 215 and the first conductive structure 206, respectively, and are electrically isolated by the isolation structure 215. The third conductive structure 207 may be another part of the bonding lead 210 connected to the die 205. In other words, the bonding lead 210 connected to the die 205 is cut off by forming the first conductive structure 206 through laser aperture, thereby forming the second conductive structure 208 and the third conductive structure 207. Since the depth of the laser aperture affects the aperture size at the top of the aperture, considering the pad size in the circuit layer 204, the laser aperture can be designed in the middle of the length of the lead 210. Additionally, in the illustrated embodiment, the lead 210 is routed from the pad 209 of the die 205 to the substrate 202. Therefore, the second conductive structure 208 is specifically adjacent to the bend of the die 205, and the bend is higher than the pad 209 of the die 205, which affects the aperture depth. In other embodiments, the lead 210 can be routed from the substrate 202 to the pad 209 of the die 205, such that the top of the bend of the lead 210 is lower than the pad 209 of the die 205, thereby avoiding any impact on the aperture depth.

[0036] In some embodiments, the substrate 202 is a leadframe. Since the leadframe below the die 205 is mostly for grounding or heat dissipation, the leads 210 can be cut by laser after bonding to prevent signal conduction to the leadframe. The leadframe may have patterned openings, wherein the second conductive structure 208 may be above and across the openings. In this embodiment, since the leadframe is electrically isolated by the patterned openings, the step of cutting the second conductive structure 208 by laser can be eliminated.

[0037] Figures 3A to 3R This is a schematic diagram illustrating the various stages of forming a packaging structure according to an embodiment of the present invention. Figure 3A As shown, a carrier 301 is provided, and a first seed layer 302 and a first photoresist layer 303 are formed on the carrier 301. Figure 3B As shown, the first photoresist layer 303 is patterned to form a first opening 305 located in the first photoresist layer. A first metal layer 306 is formed on the first seed layer 302 in the first opening 305.

[0038] exist Figure 3C In the process, the first photoresist layer 303 and the first seed layer 302 located below the first photoresist layer 303 are removed. The remaining first seed layer 302 and first metal layer 306 are formed into a first circuit layer. Then, as... Figure 3DAs shown, a first dielectric layer 310 is covered over the retained first seed layer 302 and first metal layer 306, and a second circuit layer is formed above the first dielectric layer. The second circuit layer includes circuits having a second seed layer 312 and a second metal layer 316, and a first via 318 that passes through the first dielectric layer 310 and connects to the first circuit layer. A second dielectric layer 320 is formed on the second circuit layer.

[0039] exist Figure 3E In the second dielectric layer 320, a second opening 322 extending to the underlying second circuit layer is formed. In some embodiments, the thickness of each of the first dielectric layer 310 and the second dielectric layer 320 can be in the range of 2 micrometers to 5 micrometers. A third seed layer 324 is formed above the second dielectric layer 320 and within the second opening 322. Figure 3F As shown, a patterned second photoresist layer 326 with a third opening 325 is formed above the third seed layer 324. A third metal layer 328 is formed on the third seed layer 324 within the third opening 325. Figure 3G The second photoresist layer 326 and the third seed layer 324 located below the second photoresist layer 326 are removed. The remaining third seed layer 324 and third metal layer 328 are formed into the third circuit layer. Through the above... Figures 3A to 3G The steps described above form the first to third line layers, which can be collectively referred to as line layers 204. It should be understood that forming three line layers is merely exemplary, and any number of line layers can be formed as needed.

[0040] Next, as Figure 3H and Figure 3I As shown, where, Figure 3I It is shown Figure 3H A top view of a die 205. A substrate 202 is provided, and the die 205 is placed on the substrate 202. In some embodiments, the substrate 202 may be a lead frame with patterned openings. Leads connecting the die 205 to the substrate 202 are formed by a wire bonding process. Multiple leads 210 may be connected to the same pad 209. In some embodiments, the diameter of the leads 210 may be in the range of 20 micrometers to 100 micrometers. Then as... Figure 3J An adhesive layer 212 is formed, covering the substrate 202, die 205, and lead 210. A first opening 332 is formed through the adhesive layer 212 using a laser drilling process. In some embodiments, the diameter of the first opening 332 can be in the range of 20 micrometers to 100 micrometers. The first opening 332 separates the lead 210 into a first portion 334 connected to the die 205 (i.e., the second conductive structure 208 described above) and a second portion 336 connected to the substrate 202 (i.e., the third conductive structure 207 described above). If necessary, at least one lead 210 may not be separated by the first opening.

[0041] exist Figure 3K In the middle, through the isolation structure 215, it will be connected with Figure 3G The obtained line layer 204 is attached to Figure 3J The structure obtained is as follows. The isolation structure 215 fills the first opening 332. Figure 3L In the middle, remove carrier 301. Then, as follows: Figure 3M As shown, a second opening 340 is formed using a laser drilling process. The second opening 340 passes through the circuit layer 204 and part of the adhesive layer 212. Forming the second opening 340 also removes part of the isolation structure 215 in the first opening 332. The diameter of the second opening 340 can be in the range of 80 micrometers to 250 micrometers. The second opening 340 can reach the lead 210, or the first portion of the lead 210 separated by the isolation structure 215 that is connected to the die 205. The bottom of the second opening 340 is separated from the substrate 202.

[0042] exist Figure 3N In this process, a fourth seed layer 342 is conformally formed on the circuit layer 204 and within the second opening 340, and a third photoresist layer 344 filling the second opening 340 is formed on the fourth seed layer 342. Figure 3O In this process, a third photoresist layer 344 is patterned to form a fourth opening 345 located within the third photoresist layer 344. Patterning the third photoresist layer 344 removes the third photoresist layer 344 within the second opening 340, thus exposing the second opening 340 with the fourth opening 345. A fourth metal layer 346 is filled within the fourth opening 345 and the second opening 340. The material of the fourth metal layer 346 can be, for example, Cu, Ag, Au, Ni, Pd, or Pt. In other embodiments, the fourth metal layer 346 can be formed as a conformal layer on the fourth seed layer 342, and a non-metallic or organic material is filled onto the fourth metal layer 346 within the second opening 340. The third photoresist layer 344 and the fourth seed layer 342 located below the third photoresist layer 344 are removed, such as... Figure 3P .

[0043] exist Figure 3Q In this process, a solder mask layer 348 covering the fourth metal layer 346 is formed above the circuit layer 204. Figure 3R In this process, solder balls 349 are formed that pass through solder mask 348 and are connected to the fourth metal layer 346, and the resulting structure can be cut along the dotted lines. In some embodiments, the diameter of the solder balls 349 can be in the range of 50 micrometers to 200 micrometers.

[0044] Figure 4 This is a schematic diagram of another embodiment of the packaging structure according to an embodiment of the present invention. In this embodiment, two first conductive structures 206 can be connected to the portion of the same lead 210 separated by the isolation structure 215.

[0045] Figure 5 This is a schematic diagram of another embodiment of the packaging structure according to an embodiment of the present invention. In this embodiment, similar to the above-described packaging structure is formed on both opposite sides of the substrate 202. Figure 2A The structure described.

[0046] Figure 6 This is a schematic diagram of another embodiment of the packaging structure according to an embodiment of the present invention. In this embodiment, the die includes an active device die 601 and a passive device die 602. A first conductive structure 206 may extend to connect to a connection terminal of the passive die 601.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A packaging structure, characterized in that, include: substrate; The circuit layer is located above the substrate; The die is located between the substrate and the circuit layer; A first conductive structure is connected to the circuit layer; The second conductive structure electrically connects the first conductive structure to the die, wherein the second conductive structure has a bent portion, and the second conductive structure is a conductive structure formed after the lead connecting the die and the substrate is cut off, and the first conductive structure is a conductive structure that passes through the circuit layer and the lead. An adhesive layer is located between the substrate and the circuit layer and surrounds the second conductive structure; and An isolation structure is formed in an opening through the adhesive layer and the lead wire, wherein a first side of the first conductive structure is connected to the second conductive structure, and the isolation structure is located on a second side of the first conductive structure opposite to the first side and in contact with the second side.

2. The packaging structure according to claim 1, characterized in that, in, The first conductive structure is a through hole.

3. The packaging structure according to claim 1, characterized in that, Also includes: A third conductive structure is connected to the substrate, wherein the second conductive structure and the third conductive structure are located on opposite sides of the isolation structure and are electrically isolated by the isolation structure.

4. The packaging structure according to claim 1, characterized in that, The substrate has patterned openings, wherein the second conductive structure is above and across the openings.

5. A method for forming an encapsulation structure, characterized in that, include: A die is disposed on a substrate, and the die is connected to the substrate by a lead wire; The circuit layers are stacked on top of the substrate using an adhesive layer; A through-hole is formed through the circuit layer and the lead using a laser drilling process; A first conductive structure is formed within the through-hole, and a second conductive structure is formed at the portion of the lead connected to the die. The method further includes, after connecting the die and the substrate via the lead wire: The adhesive layer is formed to cover the leads; An opening is formed that passes through the adhesive layer and through the lead wire; An isolation structure is formed in the opening. Wherein, the first side of the first conductive structure is connected to the second conductive structure, and the isolation structure is located on the second side of the first conductive structure opposite to the first side and is in contact with the second side.

6. The method according to claim 5, characterized in that, The laser drilling process that forms the through hole also removes a portion of the isolation structure.

7. The method according to claim 5, characterized in that, The isolation structure is in contact with the substrate, and the first conductive structure is spaced apart from the substrate by the adhesive layer.

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