Fan-out package structure and method for manufacturing fan-out package structure

Abstract

Embodiments of the present application provide a fan-out packaging structure and a preparation method thereof, and relate to the technical field of semiconductor packaging. In the fan-out packaging structure, a wiring combination layer is further provided with a plurality of solder grooves on the side surface away from the chip. The plurality of solder grooves are distributed on at least two sides of the conductive solder ball and are arranged close to the bottom of the conductive solder ball. When the conductive solder ball is offset from the solder ball on the substrate and the offset amount exceeds the pad position during soldering of the packaging structure on the substrate, the solder ball can melt and flow into the solder groove. As long as the sidewalls of the two solder balls are combined, a new soldering position can be formed in the solder groove, thereby improving the soldering reliability and bonding force. Meanwhile, the remaining solder grooves that do not flow into the solder can improve the air contact area of the bottom of the fan-out packaging for heat dissipation, thereby improving the heat dissipation capacity, and can also reduce warping and play a role in buffering thermal stress, thereby avoiding deformation of the packaging structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor packaging, in particular to a fan-out packaging structure and a preparation method of the fan-out packaging structure. BACKGROUND

[0002] With the rapid development of the semiconductor industry, fan-out wafer level package (FOWLP) packaging structures are widely used in the semiconductor industry. The conventional fan-out process generally adopts the method of cutting a single chip from a wafer and then packaging it on a carrier wafer. The main advantages are high-density integration, small product size, superior product performance, fast signal transmission frequency, etc. The fan-out packaging technology mainly realizes multi-pin output and smaller output pin pitch. In the prior art, the fan-out packaging structure has the problem of poor solderability when dropped for testing. At the same time, the fan-out packaging structure has the problems of warping and solder offset of the solder balls, which can easily cause false soldering and other problems. SUMMARY

[0003] The purposes of the present application include, for example, providing a fan-out packaging structure and a preparation method of the fan-out packaging structure, which can solve the problem of false soldering caused by solder offset.

[0004] Embodiments of the present application can be implemented as follows:

[0005] In a first aspect, the present application provides a fan-out packaging structure, comprising:

[0006] a chip;

[0007] a plastic package covering the chip;

[0008] a wiring combination layer arranged on one side of the plastic package;

[0009] a conductive solder ball arranged on the side of the wiring combination layer away from the chip;

[0010] wherein the wiring combination layer is electrically connected to the chip, the conductive solder ball is electrically connected to the wiring combination layer, the wiring combination layer is provided with a plurality of solder grooves on the side surface away from the chip, and the plurality of solder grooves are distributed on at least two sides of the conductive solder ball.

[0011] In an optional embodiment, the wiring combination layer comprises a wiring medium layer, an electrically conductive wiring layer, an electrically conductive soldering layer, and a protective medium layer, the wiring medium layer is arranged on one side of the plastic package, the electrically conductive wiring layer is embedded in the wiring medium layer and electrically connected with the chip, the protective medium layer is arranged on the side of the wiring medium layer away from the chip, the electrically conductive soldering layer is embedded in the protective medium layer and electrically connected with the electrically conductive wiring layer, the electrically conductive soldering ball is arranged on the electrically conductive soldering layer, and the soldering groove is arranged on the surface of the side of the protective medium layer away from the chip.

[0012] In an optional embodiment, the wiring combination layer further comprises a film medium layer and an electrically conductive column, the film medium layer is arranged on one side surface of the plastic package, the electrically conductive column is arranged in the film medium layer and electrically contacts the chip, the wiring medium layer is arranged on the side surface of the film medium layer away from the chip, and the electrically conductive wiring layer electrically contacts the electrically conductive column.

[0013] In an optional embodiment, the depth of the soldering groove is less than the thickness of the protective medium layer.

[0014] In an optional embodiment, the side surface of the wiring combination layer away from the chip is further provided with an auxiliary soldering ball, the auxiliary soldering ball is arranged around the electrically conductive soldering ball, so that the auxiliary soldering ball is arranged between every two adjacent electrically conductive soldering balls.

[0015] In an optional embodiment, each auxiliary soldering ball comprises a soldering ball body and a metal column, the metal column is arranged on the wiring combination layer, the soldering ball body is arranged on the metal column, the cross section of each metal column is rectangular, and the long axis direction of the cross sections of two adjacent metal columns is different.

[0016] In an optional embodiment, a plurality of auxiliary soldering balls are arranged in an array on the wiring combination layer, the included angle of the long axis of the cross sections of every two adjacent metal columns in the same linear direction is the same, and the long axis direction of the cross section of the metal column at the center is perpendicular to the long axis direction of the cross section of the metal column at the edge.

[0017] In an optional embodiment, the electrically conductive soldering ball is a plurality of, at least two soldering grooves are arranged between every two adjacent electrically conductive soldering balls, each soldering groove is rectangular, and the extension directions of two adjacent soldering grooves are different.

[0018] In an optional embodiment, a plurality of soldering grooves are arranged in an array on the wiring combination layer, and the extension directions of two adjacent soldering grooves are perpendicular.

[0019] In a second aspect, the present application provides a preparation method of a fan-out package structure, for preparing the fan-out package structure according to any one of the preceding embodiments, comprising:

[0020] attaching a chip on a carrier;

[0021] forming a plastic package body on the carrier, the plastic package body covering the chip;

[0022] stripping the carrier to expose the chip;

[0023] forming a wiring combination layer on a side of the plastic package body where the chip is exposed;

[0024] forming conductive solder balls on a side of the wiring combination layer away from the chip;

[0025] wherein the wiring combination layer is electrically connected to the chip, the conductive solder balls are electrically connected to the wiring combination layer, a plurality of soldering grooves are arranged on a surface of the side of the wiring combination layer away from the chip, the plurality of soldering grooves are distributed on at least two sides of the conductive solder balls, and are arranged close to the bottom of the conductive solder balls.

[0026] The beneficial effects of the embodiments of the present application include, for example:

[0027] The fan-out package structure and the preparation method thereof provided by the present application form a plastic package body by covering the chip, and then form a wiring combination layer on a side of the plastic package body, and then form conductive solder balls on a side of the wiring combination layer away from the chip, to complete the fan-out structure. Meanwhile, a plurality of soldering grooves are arranged on a surface of the side of the wiring combination layer away from the chip, the plurality of soldering grooves are distributed on at least two sides of the conductive solder balls, and are arranged close to the bottom of the conductive solder balls. The soldering grooves can be used as an offset amount for the alignment of the conductive solder balls. When the conductive solder balls are offset from the solder balls on the substrate, and the offset amount exceeds the position of the solder pad, the solder balls can melt and flow into the soldering grooves. As long as the sidewalls of the two solder balls are combined, a new soldering position can be formed in the soldering grooves, to improve the soldering reliability and the bonding force. Meanwhile, the soldering grooves that are not filled with solder can improve the air contact area of the bottom of the fan-out package, to improve the heat dissipation capacity, and can also reduce warping, to play a role in buffering thermal stress and avoiding deformation of the package structure. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0029] Figure 1 A schematic diagram of a fan-out package structure according to a first embodiment of the present application;

[0030] Figure 2 and Figure 3 A schematic diagram of a fan-out package structure according to a first embodiment of the present application;

[0031] Figure 4 A schematic diagram of a fan-out package structure according to a second embodiment of the present application from a first perspective;

[0032] Figure 5 A schematic diagram of a fan-out package structure according to a second embodiment of the present application from a second perspective;

[0033] Figure 6 A schematic diagram of a fan-out package structure according to a third embodiment of the present application;

[0034] Figure 7 A schematic diagram of a fan-out package structure according to a fourth embodiment of the present application;

[0035] Figures 8 to 12 A process flow diagram of a fan-out package structure according to a fifth embodiment of the present application.

[0036] Legend: 100 - fan-out package structure; 110 - chip; 130 - plastic package body; 150 - wiring combination layer; 151 - wiring medium layer; 153 - conductive wiring layer; 155 - conductive solder layer; 157 - protective medium layer; 158 - film medium layer; 159 - conductive pillar; 170 - conductive solder ball; 180 - solder recess; 190 - auxiliary solder ball; 191 - metal pillar; 193 - solder ball body; 200 - substrate. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0039] It should be noted that like reference numerals and letters refer to like items throughout the drawings, and once an item is defined in one drawing, it is not necessary to further define and explain it in the subsequent drawings.

[0040] In the description of the present application, it should be noted that if the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0041] In addition, if the terms "first", "second" and the like appear, they are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0042] As disclosed in the background art, the fan-out package structure in the prior art usually adopts the tin ball-to-tin ball mode to realize the upper plate action, that is, the tin balls at the bottom of the package structure are aligned with the solder balls on the pads of the substrate and welding is completed. When the output pin pitch is getting smaller and smaller, and the package size is getting smaller and smaller, the requirement for accurate alignment is getting higher and higher. When there is an offset, the tin balls cannot be accurately aligned, even if the two sides are combined, the small side welding area will result in low welding quality, and then the virtual welding phenomenon is easy to occur, which affects the performance of the device. At the same time, due to the thermal stress generated during welding, the package structure is prone to warping, which further affects the accuracy of welding, and the internal heat is difficult to release, and the heat dissipation is poor.

[0043] In order to solve the above problems, the present application provides a fan-out package structure and a fan-out package structure method. It should be noted that the features in the embodiments of the present application can be combined with each other without conflict.

[0044] First embodiment

[0045] Referring to Figure 1 The present embodiment provides a fan-out package structure 100 and a preparation method of the fan-out package structure 100, which can improve the welding reliability and welding bonding force, avoid the virtual welding phenomenon, improve the heat dissipation capacity, reduce the warping, improve the alignment accuracy, and buffer the thermal stress to avoid the deformation of the package structure.

[0046] The fan-out package structure 100 provided in this embodiment includes a chip 110, a molding compound 130, a wiring assembly layer 150, and conductive solder balls 170. The molding compound 130 covers the chip 110. The wiring assembly layer 150 is disposed on one side of the molding compound 130. The conductive solder balls 170 are disposed on the side of the wiring assembly layer 150 away from the chip 110. The wiring assembly layer 150 is electrically connected to the chip 110, and the conductive solder balls 170 are electrically connected to the wiring assembly layer 150. A plurality of soldering grooves 180 are provided on the surface of the side of the wiring assembly layer 150 away from the chip 110. The plurality of soldering grooves 180 are distributed on at least one side of the conductive solder balls 170 and are disposed closer to the bottom of the conductive solder balls 170 than the top of the conductive solder balls 170.

[0047] In this embodiment, a fan-out structure is completed by encapsulating the chip 110 with a molding compound 130, forming a wiring assembly layer 150 on one side of the molding compound 130, and then placing conductive solder balls 170 on the side of the wiring assembly layer 150 away from the chip 110. The specific fabrication process can refer to existing fan-out structures. The package structure is then soldered onto the substrate 200. Figure 2 As shown, when the conductive solder ball 170 is offset from the solder ball on the substrate 200, and the offset exceeds the position of the pad, the solder ball can melt and flow into the solder groove 180. As long as the sidewalls of the two solder balls are joined, a new soldering position can be formed within the solder groove 180, improving soldering reliability and bonding strength. At the same time, the remaining solder grooves 180 that do not receive solder can, on the one hand, increase the heat dissipation air contact area at the bottom of the fan-out package, thereby improving heat dissipation capacity, and on the other hand, reduce warpage, buffering thermal stress and preventing package structure deformation.

[0048] In this embodiment, the chip 110 is disposed on one side edge of the molding compound 130, and the side surface of the chip 110 with the pads is exposed on the molding compound 130. The wiring assembly layer 150 is disposed on the exposed side surface of the chip 110 on the molding compound 130 and directly makes electrical contact with the chip 110.

[0049] In the embodiment, the plurality of conductive soldering balls 170 are arranged on the wiring combination layer 150, and the plurality of soldering grooves 180 are also arranged between the plurality of conductive soldering balls 170. Specifically, the plurality of conductive soldering balls 170 are arranged in multiple rows, and each row of the conductive soldering balls 170 is arranged along the same line and is uniformly spaced. A plurality of soldering grooves 180 can be arranged between each two adjacent conductive soldering balls 170 in the same row, for example, two soldering grooves 180 are arranged between each two adjacent conductive soldering balls 170, and each soldering groove 180 can be rectangular or circular, so that the two sides of each conductive soldering ball 170 are provided with the soldering grooves 180, and the soldering reliability of the soldering ball is further improved when the offset occurs.

[0050] The wiring combination layer 150 includes a wiring medium layer 151, a conductive wiring layer 153, a conductive soldering layer 155, a protective medium layer 157, a film medium layer 158, and a conductive column 159. The wiring medium layer 151 is arranged on one side of the plastic package 130. The conductive wiring layer 153 is embedded in the wiring medium layer 151 and is electrically connected to the chip 110. The protective medium layer 157 is arranged on the side of the wiring medium layer 151 away from the chip 110. The conductive soldering layer 155 is embedded in the protective medium layer 157 and is electrically connected to the conductive wiring layer 153. The conductive soldering ball 170 is arranged on the conductive soldering layer 155. The soldering groove 180 is arranged on the surface of the protective medium layer 157 away from the chip 110. The film medium layer 158 is arranged on one surface of the plastic package 130. The conductive column 159 is arranged in the film medium layer 158 and is in electrical contact with the chip 110. The wiring medium layer 151 is arranged on the surface of the film medium layer 158 away from the chip 110. The conductive wiring layer 153 is in electrical contact with the conductive column 159.

[0051] It should be noted that in other preferred embodiments of the present application, the wiring combination layer 150 can also not be provided with the film medium layer 158 and the conductive column 159, and the conductive wiring layer 153 is formed by direct wiring to realize electrical connection with the chip 110.

[0052] In the embodiment, when the wiring is completed, a medium material can be first coated on the surface of the plastic package 130 to form a film medium layer 158, then the film medium layer 158 is slotted to form openings, so that the pads of the chip 110 are exposed, then the conductive pillars 159 are formed in the openings, and the conductive pillars 159 are in direct electrical contact with the pads of the chip 110. After the conductive pillars 159 are formed, a layer of medium material is again coated on the film medium layer 158 to form a wiring medium layer 151, then the wiring medium layer 151 is slotted to pattern the openings, the wiring pattern is completed, and the conductive pillars 159 are exposed, then the conductive wiring layer 153 is formed in the openings, and the conductive wiring layer 153 is in electrical contact with the conductive pillars 159. After the conductive wiring layer 153 is formed, a layer of medium material is again coated on the wiring medium layer 151 to form a protective medium layer 157, then the protective medium layer 157 is slotted to form openings and solder grooves 180, so that part of the conductive wiring layer 153 is exposed, then the conductive solder layer 155 is formed in the openings, and the conductive solder layer 155 is in electrical connection with the conductive wiring layer 153, and the solder grooves 180 are reserved at this time. Finally, the conductive solder balls 170 are formed on the conductive solder layer 155, and the fan-out structure is completed.

[0053] In the embodiment, the conductive pillars 159, the conductive wiring layer 153, and the conductive solder layer 155 can all be made of copper material, which has good electrical conductivity, and can also be other conductive metal materials. At the same time, the medium material can be silicon nitride, silicon oxynitride, polyimide, benzocyclobutene, etc., which are not listed one by one.

[0054] In the embodiment, the depth of the solder groove 180 is less than the thickness of the protective medium layer 157. Specifically, when the solder groove 180 is formed, the solder groove 180 can be formed synchronously with the openings on the protective medium layer 157, or can be formed separately. The depth of the solder groove 180 is controlled by controlling the etching depth or the laser slotting depth, so that the solder groove 180 is formed at the same time, and the conductive wiring layer 153 is prevented from being exposed by penetrating through the protective medium layer 157, thereby ensuring the protection of the internal wiring structure by the protective medium layer 157.

[0055] For reference Figure 2 and Figure 3The fan-out packaging structure 100 provided by the embodiment can be welded on a substrate 200 after being prepared. Specifically, the substrate 200 is provided with a solder pad, and the solder pad is also provided with a solder ball. In actual welding, the conductive solder ball 170 is accurately aligned with the solder ball on the substrate 200 and the solder mutual fusion is completed, so that the welding action is completed. In the case of alignment offset, the conductive solder ball 170 is not accurately aligned with the solder ball on the substrate 200, and has a certain offset amount. At this time, the solder ball on the substrate 200 can be aligned with the welding groove 180 and contact the side surface of the conductive solder ball 170. The solder can flow into the welding groove 180 after being melted, and the welding is realized by using the welding groove 180. A new welding position is formed in the welding groove 180, and the remaining welding grooves 180 can be used as a structure for increasing the air contact area of the bottom heat dissipation. Through the slotted structure, the wiring combination layer 150 has better adaptability to thermal stress, reduces the occurrence of warping, and plays a certain buffering role.

[0056] In summary, the fan-out packaging structure 100 provided by the embodiment is formed by coating the chip 110 with a plastic package 130, arranging the wiring combination layer 150 on one side of the plastic package 130, and arranging the conductive solder ball 170 on the side of the wiring combination layer 150 away from the chip 110. The fan-out structure is completed, and the wiring combination layer 150 is also provided with a plurality of welding grooves 180 on the surface away from the chip 110. The plurality of welding grooves 180 are distributed on at least two sides of the conductive solder ball 170 and are arranged close to the bottom of the conductive solder ball 170. The welding groove 180 can be used as an offset amount for the alignment of the conductive solder ball 170. When the conductive solder ball 170 and the solder ball on the substrate 200 are offset, and the offset amount exceeds the position of the solder pad, the solder ball can melt and flow into the welding groove 180. As long as the two solder ball side walls are combined, a new welding position can be formed in the welding groove 180, thereby improving the welding reliability and bonding force. At the same time, the remaining welding grooves 180 that do not flow with the solder can increase the air contact area of the bottom heat dissipation of the fan-out packaging, thereby improving the heat dissipation capacity, and can also reduce warping and play a role in buffering thermal stress, thereby avoiding deformation of the packaging structure.

[0057] Second embodiment

[0058] Referring to Figure 4 and Figure 5 The fan-out packaging structure 100 provided by the embodiment has the same basic structure, principle, and technical effects as the first embodiment. For brevity, the part not mentioned in the embodiment can be referred to the corresponding content in the first embodiment.

[0059] In the embodiment, the fan-out package structure 100 comprises a chip 110, a plastic package 130, a wiring combination layer 150, and conductive solder balls 170. The plastic package 130 covers the chip 110, the wiring combination layer 150 is arranged on one side of the plastic package 130, and the conductive solder balls 170 are arranged on the side of the wiring combination layer 150 away from the chip 110. The wiring combination layer 150 is electrically connected with the chip 110, the conductive solder balls 170 are electrically connected with the wiring combination layer 150, and a plurality of solder concaves 180 are arranged on the surface of the side of the wiring combination layer 150 away from the chip 110. The plurality of solder concaves 180 are distributed on at least two sides of the conductive solder balls 170 and are arranged close to the bottom of the conductive solder balls 170.

[0060] In the embodiment, the surface of the side of the wiring combination layer 150 away from the chip 110 is further provided with auxiliary solder balls 190. The auxiliary solder balls 190 are arranged around the conductive solder balls 170, so that each two adjacent conductive solder balls 170 are provided with an auxiliary solder ball 190. Specifically, the auxiliary solder balls 190 are arranged on the protective medium layer 157, and the auxiliary solder balls 190 are not electrically connected with the conductive wiring layer 153, that is, the auxiliary solder balls 190 only play an auxiliary soldering role and do not play an electrical connection role.

[0061] In the embodiment, the auxiliary solder balls 190 comprise solder ball bodies 193 and metal columns 191. The metal columns 191 can be copper columns which are directly formed on the surface of the protective medium layer 157, and the solder ball bodies 193 are formed on the metal columns 191 to complete soldering with the substrate 200.

[0062] In the embodiment, the auxiliary solder balls 190 and the conductive solder balls 170 are arranged in an alternating manner, and the volume of the solder ball body 193 can be consistent with that of the conductive solder ball 170. In the embodiment, the auxiliary solder balls 190 and the conductive solder balls 170 can be manufactured separately, and the height of the auxiliary solder ball 190 is slightly higher than that of the conductive solder ball 170 through control of the ball planting process, so as to ensure that the auxiliary solder ball 190 can be directly attached to the surface of the substrate 200 to complete soldering.

[0063] Of course, in other preferable embodiments, the metal column 191 can be formed together with the conductive soldering layer 155, and the conductive solder ball 170 and the solder ball body 193 can be formed simultaneously through a one-time ball planting process in actual manufacturing, so as to simplify the process steps.

[0064] It is worth noting that, in order to further improve the soldering reliability, the solder ball body 193 can completely cover the metal column 191 in the embodiment, so as to increase the soldering area. The auxiliary solder ball 190 is arranged between the two adjacent conductive solder balls 170, so as to play a role in blocking solder and avoiding bridging between the two adjacent conductive solder balls 170.

[0065] In actual welding, the conductive soldering ball 170 is aligned and welded with the soldering ball on the substrate 200, and the auxiliary soldering ball 190 is directly attached to the surface of the substrate 200. By arranging the auxiliary soldering ball 190, the weldability of the product can be improved. Moreover, the auxiliary soldering ball 190 can also share part of the stress, so that the entire packaging structure is more balanced in stress in various directions, thereby solving the problem of uneven stress.

[0066] The fan-out packaging structure 100 provided by the embodiment is provided with auxiliary soldering balls 190 around the conductive soldering balls 170, and the auxiliary soldering balls 190 do not participate in electrical connection. On the premise of ensuring electrical connection performance, the weldability of the product can be further improved, so that the welding between the packaging structure and the substrate 200 is more reliable. At the same time, the main direction of the stress received by the conductive soldering balls 170 on the packaging product is different, and the entire packaging structure is subjected to stress in various directions (such as in the process of machine assembly and transmission), thereby causing uneven stress of the packaging product. By arranging the auxiliary soldering balls 190, part of the stress can be shared, so that the entire packaging structure is more balanced in stress in various directions, thereby solving the problem of uneven stress. Moreover, the auxiliary soldering balls 190 are arranged between the two adjacent conductive soldering balls 170, which can avoid the occurrence of bridging phenomenon.

[0067] Third Embodiment

[0068] For reference Figure 4 and Figure 6 The embodiment provides a fan-out packaging structure 100, the basic structure and principle and the technical effect generated are the same as those of the first embodiment. For brief description, the part not mentioned in the embodiment can be referred to the corresponding content in the first embodiment.

[0069] In the embodiment, the fan-out package structure 100 comprises a chip 110, a plastic package 130, a wiring combination layer 150, and conductive solder balls 170. The plastic package 130 covers the chip 110, the wiring combination layer 150 is arranged on one side of the plastic package 130, and the conductive solder balls 170 are arranged on the side of the wiring combination layer 150 away from the chip 110. The wiring combination layer 150 is electrically connected with the chip 110, the conductive solder balls 170 are electrically connected with the wiring combination layer 150, the surface of the side of the wiring combination layer 150 away from the chip 110 is provided with a plurality of soldering grooves 180, the plurality of soldering grooves 180 are distributed on at least two sides of the conductive solder balls 170 and are arranged close to the bottom of the conductive solder balls 170. The surface of the side of the wiring combination layer 150 away from the chip 110 is also provided with auxiliary solder balls 190, the auxiliary solder balls 190 are arranged around the conductive solder balls 170, so that the auxiliary solder balls 190 are arranged between every two adjacent conductive solder balls 170. Specifically, the auxiliary solder balls 190 are arranged on the protective medium layer 157, and the auxiliary solder balls 190 are not electrically connected with the conductive wiring layer 153, that is, the auxiliary solder balls 190 only play a role in auxiliary soldering and do not play a role in electrical connection.

[0070] In the embodiment, each auxiliary solder ball 190 comprises a solder ball body 193 and a metal column 191. The metal column 191 is arranged on the wiring combination layer 150, and the solder ball body 193 is arranged on the metal column 191. The cross section of each metal column 191 is rectangular, and the long axis directions of the cross sections of adjacent two metal columns 191 are different. Specifically, each metal column 191 is a rectangular column, and the long axis direction of the cross section of the metal column 191 refers to the long side direction of the rectangular column. By adopting different arrangement directions, the plurality of auxiliary solder balls 190 can pre-apply stresses in different directions, so as to better eliminate soldering stress.

[0071] In the embodiment, the plurality of auxiliary solder balls 190 are arranged in an array on the wiring combination layer 150. The included angle of the long axis of the cross section of every two adjacent metal columns 191 in the same linear direction is the same, and the long axis direction of the cross section of the metal column 191 at the center is perpendicular to the long axis direction of the cross section of the metal column 191 at the edge. Specifically, the plurality of auxiliary solder balls 190 are designed to rotate in the direction extending from the center to the two side edges. For example, the long axis direction of the cross section of the metal column 191 at the center is arranged along O°, and the long axis direction of the cross section of the metal column 191 at the edge is arranged along 90°. The plurality of auxiliary solder balls 190 gradually rotate from the center to the edge, so as to better eliminate soldering stress.

[0072] For example, there are 7 rows of auxiliary solder balls 190, the long axis direction of the section of the middle metal column 191 is 0°, the angle between every two adjacent metal columns 191 is 30°, and the long axis direction of the metal column 191 at the edge is 90°. At the same time, in the same row of auxiliary solder balls 190, the metal columns 191 can also adopt a rotating design. With this structure, the metal columns 191 at the middle and the edge adopt a double-layer vertical structure, and each layer can better reduce stress, thereby improving the reliability of the product structure.

[0073] Fourth embodiment

[0074] For reference Figure 1 and Figure 7 The present embodiment provides a fan-out package structure 100, which has the same basic structure and principle and technical effects as the first embodiment. For brevity, the part of the present embodiment not mentioned can be referred to the corresponding content in the first embodiment.

[0075] In the present embodiment, the fan-out package structure 100 includes a chip 110, a plastic package body 130, a wiring combination layer 150, and conductive solder balls 170. The plastic package body 130 covers the chip 110, the wiring combination layer 150 is arranged on one side of the plastic package body 130, and the conductive solder balls 170 are arranged on the side of the wiring combination layer 150 away from the chip 110. The wiring combination layer 150 is electrically connected to the chip 110, and the conductive solder balls 170 are electrically connected to the wiring combination layer 150. The surface of the side of the wiring combination layer 150 away from the chip 110 is provided with a plurality of soldering grooves 180. The plurality of soldering grooves 180 are distributed on at least two sides of the conductive solder balls 170 and are arranged close to the bottom of the conductive solder balls 170. The conductive solder balls 170 are a plurality of conductive solder balls, at least two soldering grooves 180 are arranged between every two adjacent conductive solder balls 170, and each soldering groove 180 is in a rectangular shape.

[0076] In the present embodiment, the extension directions of the adjacent two soldering grooves 180 are different. Specifically, the extension directions of the adjacent two soldering grooves 180 are different, which can realize the flow direction in different directions, so that at least one soldering groove 180 can slow down the flow speed of the solder, thereby achieving the effect of blocking the rapid diffusion of the solder to the surrounding.

[0077] In this embodiment, a plurality of solder grooves 180 are arrayed on the wiring assembly layer 150, and the extending directions of two adjacent solder grooves 180 are perpendicular. Specifically, two solder grooves 180 are provided between every two adjacent conductive solder balls 170, and the extending directions of the two solder grooves 180 are perpendicular, with the plurality of solder grooves 180 arranged alternately and perpendicularly. By adopting an alternating groove structure, on the one hand, the transverse grooves are adapted to the solder flow direction, which can improve the solderability between solder balls and improve the flowability of solder balls; on the other hand, the longitudinal grooves can act as a barrier to prevent the solder balls from continuing to flow. By adopting an alternating design, the solder flowability problem can be better solved.

[0078] The fan-out package structure 100 provided in this embodiment features multiple solder grooves 180 between adjacent conductive solder balls 170, with adjacent solder grooves 180 arranged in mutually perpendicular directions. One solder groove 180 serves to allow solder to overflow, improving solder flow and thus enhancing the soldering strength between solder balls. The other solder groove 180 acts as a barrier, preventing further solder flow and avoiding bridging. Furthermore, the staggered design better addresses stress release issues, thereby preventing soldering stress concentration.

[0079] Fifth embodiment

[0080] This embodiment provides a method for preparing a fan-out packaging structure 100, which is used to prepare the fan-out packaging structure 100 provided in the first embodiment, second embodiment, third embodiment or fourth embodiment.

[0081] The method for fabricating the fan-out package structure 100 provided in this embodiment includes the following steps:

[0082] S1: Chip 110 is mounted on a vehicle.

[0083] Specifically, in conjunction with see Figure 8 First, a carrier is provided, an adhesive layer is applied to the carrier, and then a chip 110 is mounted with its pads facing down. The carrier can be made of materials such as glass, silicon dioxide, or metal, and the adhesive layer can be a UV adhesive layer, the material of which can be separated by UV light. Specifically, the adhesive layer can be epoxy resin, etc., cured by UV (ultraviolet) or heat, and serves as a separation layer from the subsequently formed chip 110 package structure, facilitating the removal of the carrier.

[0084] S2: Form a plastic encapsulation 130 on the carrier to cover the chip 110.

[0085] Specifically, in conjunction with see Figure 9After the chip 110 is mounted, a plastic encapsulation process is used to form a plastic encapsulation body 130 to protect the bottom structure.

[0086] S3: peel off the carrier to expose the chip 110.

[0087] Specifically, referring to Figure 10 The carrier is peeled off from the plastic encapsulation body 130 by irradiating UV light, and the adhesive layer is removed after peeling off, so that the chip 110 is exposed.

[0088] S4: form a wiring combination layer 150 on the side of the plastic encapsulation body 130 where the chip 110 is exposed.

[0089] Specifically, referring to Figure 11 The prepared plastic encapsulation body 130 is turned over, and a medium material is spin-coated on the surface of the plastic encapsulation body 130 to form a film medium layer 158. The film medium layer 158 can be formed by depositing a medium material through a physical vapor deposition process (PVD), a chemical vapor deposition process (CVD), or the like. Then, laser grooving is performed on the film medium layer 158 to form openings, so that the pads of the chip 110 are exposed. Then, a conductive pillar 159 is formed in the openings. The conductive pillar 159 can be formed in the openings by one of a physical vapor deposition process (PVD), a chemical vapor deposition process (CVD), sputtering, electroplating, or chemical plating. The conductive pillar 159 can be a copper pillar and directly contacts the pads of the chip 110. After the conductive pillar 159 is formed, a medium material is spin-coated on the film medium layer 158 to form a wiring medium layer 151. Then, grooving is performed on the wiring medium layer 151 to pattern the openings, so that the conductive pillar 159 is exposed. Then, a conductive wiring layer 153 is formed in the openings. The conductive wiring layer 153 contacts the conductive pillar 159. After the conductive wiring layer 153 is formed, a medium material is spin-coated on the wiring medium layer 151 to form a protective medium layer 157. Then, grooving is performed on the protective medium layer 157 to form openings and solder grooves 180, so that part of the conductive wiring layer 153 is exposed. Then, a conductive solder layer 155 is formed in the openings. The conductive solder layer 155 contacts the conductive wiring layer 153. At this time, the solder grooves 180 are reserved. Finally, a conductive solder ball 170 is formed on the conductive solder layer 155, and the fan-out structure is completed. The medium material can be silicon nitride, silicon oxynitride, polyimide, benzocyclobutene, or the like.

[0090] It should be noted that the solder grooves 180 are located on the protective medium layer 157. The solder grooves 180 can be formed by grooving together with the openings used to form the conductive solder layer 155, or can be formed by grooving separately. When the conductive solder layer 155 is formed, the metal material does not cover the area where the solder grooves 180 are located, so that the solder grooves 180 are reserved.

[0091] S5: Forming conductive solder balls 170 on the side of the wiring combination layer 150 away from the chip 110.

[0092] Specifically, in combination with the above description, Figure 12 After the step of forming the conductive solder layer 155, the conductive solder balls 170 are formed on the conductive solder layer 155 by steel mesh printing or ball planting, and the material of the conductive solder balls 170 can be SnAg, SnAgCu, etc.

[0093] After the ball planting is completed, a cutting process is performed, thereby forming a final product.

[0094] It should be noted that when preparing the fan-out packaging structure 100 provided in the second embodiment or the third embodiment, the step S5 also needs to form auxiliary solder balls 190, which can be formed together with the conductive solder balls 170 or separately.

[0095] In this embodiment, the wiring combination layer 150 is electrically connected with the chip 110, the conductive solder balls 170 are electrically connected with the wiring combination layer 150, and the wiring combination layer 150 is provided with a plurality of solder grooves 180 on the side surface away from the chip 110, the plurality of solder grooves 180 are distributed on at least two sides of the conductive solder balls 170 and are arranged close to the bottom of the conductive solder balls 170.

[0096] The preparation method of the fan-out packaging structure 100 provided by the application, by forming a plastic package 130 outside the chip 110, arranging a wiring combination layer 150 on one side of the plastic package 130, and then arranging conductive solder balls 170 on the side of the wiring combination layer 150 away from the chip 110, the fan-out structure is completed, and the wiring combination layer 150 is also provided with a plurality of solder grooves 180 on the side surface away from the chip 110, the plurality of solder grooves 180 are distributed on at least two sides of the conductive solder balls 170 and are arranged close to the bottom of the conductive solder balls 170, wherein the solder grooves 180 can be used as the offset of the conductive solder balls 170, when the conductive solder balls 170 are offset from the solder balls on the substrate 200 and the offset exceeds the pad position, the solder balls can melt and flow into the solder grooves 180, as long as the sidewalls of the two solder balls are combined, a new soldering position can be formed in the solder grooves 180, thereby improving the soldering reliability and bonding force. At the same time, the remaining solder grooves 180 which do not flow with solder can improve the air contact area of the bottom of the fan-out packaging for heat dissipation, thereby improving the heat dissipation capacity, and on the other hand, it can also reduce warping and play a role in buffering thermal stress, thereby avoiding deformation of the packaging structure.

[0097] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A fan-out package structure, characterized by, The chip is covered by a plastic package, a wiring combination layer is arranged on one side of the plastic package, and a conductive solder ball is arranged on the side of the wiring combination layer away from the chip. The wiring combination layer and the chip are electrically connected, the conductive solder ball and the wiring combination layer are electrically connected, the surface of the side of the wiring combination layer away from the chip is provided with a soldering groove, and the soldering groove is distributed on at least one side of the conductive solder ball. The conductive solder ball is a plurality of, at least two soldering grooves are arranged between each adjacent two conductive solder balls, each soldering groove is rectangular, and the extension directions of adjacent two soldering grooves are different, so that at least one soldering groove can slow down the flow of solder and block the spread of solder around. The surface of the side of the wiring combination layer away from the chip is also provided with an auxiliary solder ball, the auxiliary solder ball is arranged around the conductive solder ball, so that the auxiliary solder ball is arranged between each adjacent two conductive solder balls. Each auxiliary solder ball includes a solder ball body and a metal column, the metal column is arranged on the wiring combination layer, the solder ball body is arranged on the metal column, the cross section of each metal column is rectangular, and the long axis directions of the cross sections of adjacent two metal columns are different. A plurality of auxiliary solder balls are arranged in an array on the wiring combination layer, the long axis angles of the cross sections of each adjacent two metal columns in the same straight line direction are the same, the long axis direction of the cross section of the metal column at the center is perpendicular to the long axis direction of the cross section of the metal column at the edge, and the plurality of auxiliary solder balls are designed in a rotating manner from the center to the two side edges. The wiring combination layer includes a wiring medium layer, a conductive wiring layer, a conductive soldering layer and a protective medium layer. The wiring medium layer is arranged on one side of the plastic package, the conductive wiring layer is embedded in the wiring medium layer and electrically connected with the chip, the protective medium layer is arranged on the side of the wiring medium layer away from the chip, the conductive soldering layer is embedded in the protective medium layer and electrically connected with the conductive wiring layer, the conductive solder ball is arranged on the conductive soldering layer, and the soldering groove is arranged on the surface of the side of the protective medium layer away from the chip.

2. The fan-out package structure of claim 1, wherein, The wiring combination layer further includes a film medium layer and a conductive column.

3. The fan-out package structure of claim 2, wherein, The film medium layer is arranged on one surface of the plastic package, the conductive column is arranged in the film medium layer and electrically contacts with the chip, the wiring medium layer is arranged on the surface of the side of the film medium layer away from the chip, and the conductive wiring layer electrically contacts with the conductive column.

4. The fan-out package structure of claim 2, wherein, The depth of the soldering groove is less than the thickness of the protective medium layer.

5. A method for manufacturing a fan-out package structure according to any one of claims 1 to 4, wherein The chip is attached on a carrier, a plastic package covering the chip is formed on the carrier, the carrier is peeled off to expose the chip, a wiring combination layer is formed on the side of the plastic package exposing the chip, and a conductive solder ball is formed on the side of the wiring combination layer away from the chip. ​ ​ ​ ​ ​ The wiring combination layer is electrically connected with the chip, the conductive soldering ball is electrically connected with the wiring combination layer, a plurality of welding grooves are arranged on the side surface of the wiring combination layer away from the chip, the plurality of welding grooves are distributed on at least two sides of the conductive soldering ball, and the bottom of the conductive soldering ball is arranged close to the plurality of welding grooves.

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