Electronic package assembly and method of forming electronic package assembly
By adopting a double-sided molded packaging substrate and pressurization process in semiconductor packaging, the problems of complex and cost-ineffective high interconnect structure processes in the prior art are solved, and the formation of electronic packaging components with simple processes and high output is achieved.
Patent Information
- Application Number
- CN202311414659.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-27
- Publication Date
- 2025-04-29
AI Technical Summary
Existing semiconductor packaging technologies are complex and cost-effective when forming high interconnect structures, affecting output.
The double-sided molding (DSM) package substrate is used to reshape the solder bumps of the backward and forward conductive blocks through a pressing process to ensure horizontal alignment of the top surface of the conductive block, thereby simplifying the process and increasing yield.
The formation of electronic packaging components with simple processes and high output is achieved, which improves the uniformity of conductive blocks on both sides of the packaging substrate, and reduces structural defects and problems caused by complex processes.
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Figure CN119905411A_ABST
Abstract
Description
Technical Field
[0001] The present application relates generally to semiconductor packaging technology and, more particularly, to electronic package assemblies and methods of forming electronic package assemblies. Background Art
[0002] The semiconductor industry has been facing complex integration challenges as consumers want their electronic products to be smaller, faster, and higher performing, with more and more functions packed into a single device. In recent years, semiconductor packages have been manufactured in smaller sizes to increase the density of electronic components. Generally, a semiconductor package may include major functional modules, such as a semiconductor chip and an interconnect structure. However, it should be noted that certain interconnect formation processes, such as stacking multiple layers of solder balls in a single through-hole to achieve a higher interconnect structure, may be complex and not cost-effective. In addition, such complex processes may adversely affect the yield of semiconductor packages incorporating such interconnect structures.
[0003] Therefore, a method for forming an electronic package assembly with simple process and high yield is needed. Summary of the invention
[0004] The purpose of the present application is to provide a method for forming an electronic packaging assembly with simple process and high yield.
[0005] According to one aspect of the present application, the present invention provides an electronic packaging component and a method for forming the electronic packaging component. The method comprises: providing a packaging substrate having a front surface and a rear surface, wherein a plurality of groups of forward conductive pads are formed on the front surface of the packaging substrate, and a plurality of groups of rear conductive pads are formed on the rear surface of the packaging substrate; attaching a plurality of rear conductive blocks to the rear surface of the packaging substrate through rear solder bumps, wherein each of the rear conductive blocks is aligned with a group of rear conductive pads in the plurality of groups of rear conductive pads; loading the packaging substrate on a first bottom mold, wherein the plurality of rear conductive blocks face upward, and pressing the plurality of rear conductive blocks against the first bottom mold with a first top mold, so that the rear solder bumps are reshaped and the plurality of rear conductive pads are aligned; The top surfaces of the electrical blocks are horizontally aligned with each other; a back mold cover is formed between the packaging substrate and the first top mold; a plurality of forward conductive blocks are attached to the forward surface of the packaging substrate through forward solder bumps, wherein each of the forward conductive blocks is aligned with a group of forward conductive pads in the plurality of groups of forward conductive pads; the plurality of packaging substrates are loaded onto a second bottom mold, wherein the forward conductive blocks face upward, and the plurality of forward conductive blocks are pressed against the second bottom mold with a second top mold to reshape the forward solder bumps and horizontally align the top surfaces of the plurality of forward conductive blocks with each other; and a forward mold cover is formed between the packaging substrate and the second top mold.
[0006] According to another aspect of the present application, the present invention provides an electronic packaging component and a method for forming the electronic packaging component. The method comprises: providing a packaging substrate having a front surface and a rear surface, wherein a plurality of groups of forward conductive pads are formed on the front surface of the packaging substrate, and a plurality of groups of rear conductive pads are formed on the rear surface of the packaging substrate; attaching a plurality of forward conductive blocks to the front surface of the packaging substrate through forward solder bumps, wherein each of the forward conductive blocks is aligned with a group of forward conductive pads in the plurality of groups of forward conductive pads; attaching a plurality of rear conductive blocks to the rear surface of the packaging substrate through rear solder bumps, wherein each of the rear conductive blocks is aligned with a group of rear conductive pads in the plurality of groups of rear conductive pads; A plurality of forward conductive blocks and a plurality of backward conductive blocks are aligned with each other; the packaging substrate is loaded between a top mold and a bottom mold, and the plurality of forward conductive blocks and the plurality of backward conductive blocks are pressed against the packaging substrate by the top mold and the bottom mold so that the forward solder bumps and the backward solder bumps are reshaped, and the top surfaces of the plurality of forward conductive blocks are horizontally aligned with each other, and the top surfaces of the plurality of backward conductive blocks are horizontally aligned with each other; a forward mold cover is formed between the front surface of the packaging substrate and the top mold; and a backward mold cover is formed between the backward surface of the packaging substrate and the bottom mold.
[0007] It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and do not limit the present invention. In addition, the accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, are used to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The drawings referred to herein form part of the specification. Unless the detailed description explicitly indicates otherwise, the features shown in the drawings only illustrate some embodiments of the present application, not all embodiments of the present application, and readers of this specification should not make contrary inferences.
[0009] Figures 1A to 1I Various steps of a method for forming an electronic package assembly according to a first embodiment of the present application are shown.
[0010] Figures 2A to 2H Various steps of a method for forming an electronic package assembly according to a second embodiment of the present application are shown. DETAILED DESCRIPTION
[0011] The following detailed description of exemplary embodiments of the present application refers to the accompanying drawings that form a part of the description. The drawings illustrate specific exemplary embodiments in which the present application can be practiced. The detailed description including the drawings describes these embodiments in sufficient detail to enable a person skilled in the art to practice the present application. A person skilled in the art may further utilize other embodiments of the present application and make logical, mechanical and other changes without departing from the spirit or scope of the present application. Therefore, the reader of the following detailed description should not interpret the description in a limiting sense, and only the appended claims define the scope of the embodiments of the present application.
[0012] In this application, unless otherwise expressly stated, the use of the singular includes the plural. In this application, unless otherwise expressly stated, the use of "or" means "and / or". In addition, the use of the term "comprising" is not limiting. In addition, unless otherwise expressly stated, terms such as "element" or "component" encompass both elements and components that include one unit and elements and components that include more than one subunit. In addition, the section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.
[0013] As used herein, for ease of description, spatially relative terms such as "under," "below," "above," "above," "up," "upper," "lower," "left," "right," "vertical," "horizontal," "side," etc. may be used herein to describe the relationship of one element or feature to another element (or elements) or feature (or features), as shown in the drawings. In addition to the orientation depicted in the drawings, spatially relative terms are intended to cover different orientations of the device in use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein may be interpreted accordingly. It should be understood that when an element is referred to as being "connected to" or "coupled to" another element, the element may be directly connected to or coupled to the other element, or there may be intermediate elements.
[0014] As described above, a way to form a higher interconnect structure in a semiconductor package (for example, in a mold cover of such a semiconductor package) is to stack multiple layers of solder balls in a single through hole. However, this approach may be complicated in the process, especially in a multi-layer package. As an alternative, preformed conductive blocks such as eBars (which have multiple conductive pillars built in a single block) can be installed in through holes or cavities on a package substrate to form a higher interconnect structure. The inventors of the present application have noticed that semiconductor packages containing preformed conductive blocks have relatively low yields and low reliability. After studying samples of semiconductor packages, the inventors found that a double-sided molded (DSM) package has conductive blocks on both sides, and due to the size and height differences of the solder bumps that mount the conductive blocks on the package substrate, there may be significant height differences between two or more preformed conductive blocks on the same package substrate. In order to solve this problem, a new method for attaching a conductive block to a DSM package substrate is provided, wherein the method introduces a one-step or two-step pressing step to obtain solder bumps with substantially uniform height on each side of the package substrate. The method may be used to form an electronic package assembly such as a double sided molded (DSM) package or a multi-layer package as part of a step in a formation process or as part of a package formation step.
[0015] Figures 1A to 1I The various steps of the method for forming an electronic packaging assembly according to an embodiment of the present application are shown. Figures 1A to 1I The method is described in more detail.
[0016] like Figure 1A As shown, the package substrate 100 has embedded interconnects. The package substrate 100 includes a front surface 100a and a back surface 100b that are opposite to each other. In some embodiments, the electronic package assembly may be a DSM package, and therefore, the front surface 100a and the back surface 100b of the package substrate 100 may be used as a platform for mounting (one or more) electronic components and conductive blocks. A plurality of groups of forward conductive pads (not shown) may be formed on the front surface 100a and / or the back surface 100b of the package substrate 100 for mounting electronic components and conductive blocks. It is understood that the plurality of groups of forward conductive pads and the back conductive pads may be exposed portions of interconnects formed in the package substrate 100.
[0017] like Figure 1B As shown, solder material is deposited onto the rear surface 110b of the package substrate 100 to form a plurality of rear solder bumps 110a on the plurality of groups of rear conductive pads. The solder bump material may be aluminum (Al), tin (Sn), nickel (Ni), gold (Au), silver (Ag), lead (Pb), bismuth (Bi), copper (Cu) or a combination thereof, and an optional flux solution.
[0018] Next, at least one back-facing electronic component 115 is attached to the back-facing surface 100b of the package substrate 100 via an additional solder bump 110b, thereby forming an electrical connection between the interconnection line and the back-facing electronic component 115. In some embodiments, the back-facing electronic component 115 may be a semiconductor chip or a smaller semiconductor package. It is understood that more back-facing electronic components 115 can be mounted on the back-facing surface 100b. In addition, a plurality of back-facing conductive blocks 113 are also attached to the back-facing surface 100b of the package substrate 100 via back-facing solder bumps 110a, thereby forming an electrical connection between the interconnection line and the back-facing conductive blocks 113. The back-facing conductive blocks 113 may be eBar blocks including built-in conductive pillars 111 such as copper pillars and insulating base materials separating the copper pillars from each other. Two or more back-facing conductive blocks 113 may be mounted at different positions on the back-facing surface 100b, for example, on opposite sides of the back-facing electronic component 115. In an embodiment, the plurality of back-facing conductive blocks 113 are higher than the back-facing electronic component 115. In this way, the electronic package assembly can be electrically connected to other external electronic devices via the plurality of rear-facing conductive blocks 113 while keeping the rear-facing electronic components 115 isolated from other devices. In some embodiments, the rear-facing conductive blocks 113 and at least one rear-facing electronic component 115 can be attached to the rear surface 100b of the package substrate 100 at the same time, while in some other embodiments, the rear-facing conductive blocks 113 can be attached to the rear surface 100b of the package substrate 100 before or after the rear-facing electronic components 115 are attached.
[0019] As described above, each of the plurality of rearward conductive blocks 113 is aligned with a group of rearward conductive pads in the plurality of groups of rearward conductive pads. In this example, the plurality of rearward conductive blocks 113 are positioned on opposite sides of the rearward electronic component 115, spaced apart by a relatively long distance. However, it can be appreciated that the rearward electronic component 115 and the rearward conductive blocks 113 can be attached to the rearward surface 100b of the package substrate 100 based on different distances and arrangements. In addition, more rearward conductive blocks 113 can be attached to the rearward surface 100b, depending on the actual needs of the electronic package assembly.
[0020] Still refer to Figure 1B, the back conductive block 113 may include an eBar block. In this example, each eBar block further includes a plurality of conductive pillars 111 and a dielectric layer 112 (e.g., an insulating polymer material or a composite) surrounding the plurality of conductive pillars 111. More specifically, the bottom surface of the conductive pillar 111 is exposed from the bottom surface of the dielectric layer 112 for contacting the back solder bump 110a. Similarly, the top surface of the conductive pillar 111 is exposed from the top surface of the dielectric layer 112. In addition, a conductive pad may be formed on the surface of the conductive pillar 111, and a solder bump may be formed on the conductive pad in a subsequent process for electrical contact with an external device. In some embodiments, the conductive pillars 111 in some back conductive blocks 113 are electrically connected to each other. In some other embodiments, the conductive pillars 111 in some back conductive blocks 113 are not electrically connected to each other, but are electrically isolated from each other to form a separate electrical path. In addition, the number of conductive pillars 111 contained in each back conductive block 113 may vary according to the actual needs of the electronic packaging assembly.
[0021] As described above, due to the non-uniformity of the back surface 100b of the package substrate 100, the non-uniformity of the formation process of the back solder bump 100a, and the inconsistency of the attachment process of the back conductive block 113 to the back surface 100b of the package substrate 100, the back conductive block 113 at different positions on the back surface 100b of the package substrate 100 may have different heights. For example, the height of the back solder bump 110a below the back conductive block 113 on the left side of the back electronic component 115 may be different from the height of the back solder bump 110a below the back conductive block 113 on the right side of the back electronic component 115, thereby presenting a height difference between the top surfaces of the back conductive blocks 113. In addition, the top surface of the back conductive block 113 may also have a tilt problem. A pressing process may be performed to solve this problem.
[0022] like Figure 1C As shown, the package substrate 100 is loaded on the first bottom mold 121, wherein the plurality of back-facing conductive blocks 113 face upward. The first bottom mold 121 can be used to place the package substrate 100 and provide an upward supporting force when the back-facing conductive blocks 113 are pressed against the first bottom mold 121. In a preferred embodiment, the length of the first bottom mold 121 in the horizontal direction can be greater than the length of the package substrate 100 to provide sufficient and balanced force to support the package substrate 100.
[0023] Next, the plurality of back-facing conductive blocks 113 are pressed against the first bottom mold 121 using the first top mold 130 to reshape the back-facing solder bump 110a. In this example, all of the back-facing conductive blocks 113 are in contact with the same surface of the first top mold 130 to simultaneously receive force from the first top mold 130. During the pressing process, the back-facing solder bump 110a can be largely flattened, for example, from a circular shape to an elliptical shape or even a disc shape, thereby reducing the distance from the top surface of the back-facing conductive block 113 to the back-facing surface 100b of the package substrate 100 in a controllable manner. After the pressing step, the top surfaces of the plurality of back-facing conductive blocks 113 are horizontally aligned with each other, which can enhance the uniformity of the structure of the back-facing conductive blocks 113. It can be understood that the amount of height reduction of the back-facing solder bump 110a can be different, depending on the original height of the back-facing solder bump. The higher the original height, the greater the degree of height compression or reduction. In addition, since the rear-facing conductive mass 113 , especially the inner conductive pillar 111 , may have a greater rigidity than the rear-facing solder bump 110 a , the pressing process may not reshape the rear-facing conductive mass 113 .
[0024] exist Figure 1C In the illustrated embodiment, the first top mold 130 may include a first base plate 132 and a first flexible film 131, and the first flexible film 131 contacts the top surface of the plurality of back-facing conductive blocks 113 during the pressing step. The first flexible film 131 may be used as a slow-release film, which provides a buffer zone between the first base plate 132 and the back-facing conductive blocks 113 to protect the back-facing conductive blocks 113 from potential damage during the pressing step. The material of the first flexible film 131 may include foam plastic, rubber, etc. In some embodiments, the first flexible film 131 may be a multi-layer structure, which provides a finer buffer zone between the first base plate 132 and the back-facing conductive blocks 113. In some other embodiments, the flexible film 131 may be omitted, wherein the first base plate 132 may directly contact the surface of the plurality of back-facing conductive blocks 113. In this example, since the plurality of back-facing conductive blocks 113 are higher than the back-facing electronic components 115, the back-facing electronic components 115 are not affected when the plurality of back-facing conductive blocks 113 are pressed by the first top mold 130. Therefore, when the pressing step is completed, a gap may exist between the top surface of the electronic component 115 facing away from the electronic component and the bottom surface of the first top mold 130 , so that the electronic component 115 facing away from the electronic component may be completely encapsulated subsequently.
[0025] In addition, in some embodiments, the bottom surface of the first top mold 130 is an extended flat surface. In some other embodiments, the first top mold 130 may include an inner cavity, the bottom surface of which is located within the first top mold 130, and the top surfaces of the plurality of conductive blocks 113 facing away from each other are in contact with the bottom surface of the inner cavity. In some examples, the inner cavity of the first top mold 130 may be used as an injection molding chamber for a subsequent molding process. In other words, both the pressing process and the molding process may be implemented by a single set of tools.
[0026] It can be understood that since the pressing step can reduce the height of the back solder bump 110a, the corresponding cross-section of the solder bump 110a in the horizontal direction can be expanded to a certain extent. However, the pressing step can be implemented so that the back solder bumps 110a on each group of back conductive pads are reshaped but not connected to each other to avoid potential short circuit risks. Therefore, during the pressing step, the pressure applied to the first top mold 130 should be determined based on the space and distance between adjacent back solder bumps 110a. In some embodiments, a stopper can be provided between the first top mold 130 and the first bottom mold 121 to limit the maximum distance that the first top mold 130 can move toward the first bottom mold 121.
[0027] It is understood that the pressing step may be performed after the reflow step is performed on the back-facing solder bump 110a. In addition, the back-facing solder bump 110a may exhibit a deformable characteristic and be able to reshape when an external force is applied.
[0028] Then, if Figure 1DAs shown, the molding material is formed between the first top mold 130 and the back surface 100b of the package substrate 100 to form a back mold cover 140 to encapsulate the plurality of back conductive blocks 113 and the back electronic components 115. In some embodiments, a molding process, such as a film assisted molding (FAM) process, is used to form the back mold cover 140, which covers the top surface and the side surface of the back electronic components 115 and the side surface of the back conductive blocks 113 for encapsulation. The molding material is first liquefied by heat and pressure, and then forced into a closed mold cavity (e.g., a mold cavity in the first top mold 130), and is maintained in the closed mold cavity under additional heat and pressure until all the materials are solidified. The encapsulated package can be easily released from the groove by the FAM process because the molding material contacts the auxiliary film instead of the metal mold. In addition, the film can also act as a soft cushion, thereby reducing the wear of the mold parts. The molding material used in the FAM process may include an extremely viscous type material and a liquid silicone material. It is understood that when the first top mold 130 is used for pressing and molding, the auxiliary film may include the first flexible film 131 of the first top mold 130. In some other embodiments, another set of molds, instead of the first top mold 130 and the first bottom mold 121 used in the pressing process, may be used for the molding process. In addition, in some other embodiments, other molding techniques may also be used to form the back mold cover 140. After the back mold cover 140 is formed, the top surface of the back conductive block 113 is exposed from the top surface of the back mold cover 140.
[0029] like Figure 1EAs shown, the substrate 100 and the various elements thereon can be removed from the first top mold 130 and the first bottom mold 121. The substrate 100 can then be flipped over so that other elements can be further attached to the forward surface 100a of the substrate. Specifically, a plurality of forward solder bumps 150a can be formed on a plurality of groups of forward conductive pads. In addition, the plurality of forward conductive blocks 153 are also attached to the forward surface 100a of the package substrate 100 via the forward solder bumps 150a, thereby forming an electrical connection between the interconnection line and the forward conductive blocks 153. Each of the forward conductive blocks 153 is aligned with one of the groups of forward conductive pads. The forward conductive block 153 can be an eBar block comprising a plurality of conductive pillars 151 and a dielectric layer 152 surrounding the plurality of conductive pillars 151. More specifically, the bottom surface of the conductive pillar 151 is exposed from the bottom surface of the dielectric layer 152 for contacting the forward solder bumps 150a. Similarly, the top surface of the conductive pillar 151 is exposed from the top surface of the dielectric layer 152 for electrical connection to other devices. In addition, at least one front electronic component 155 is attached to the front surface 100a of the package substrate 100 through an additional solder bump 150b, and the front conductive block 153 is higher than the front electronic component 155. The detailed attachment process and structure of the front conductive block 153, the front solder bump 150a, and the front electronic component 155 are similar to the attachment process and structure of the rear conductive block 113, the rear solder bump 110a, and the rear electronic component 155 shown in 1B.
[0030] Still refer to Figure 1E , the forward conductive blocks 153 at different positions on the forward surface 100a of the package substrate 100 may have different heights. For example, the height of the forward solder bump 150a under the forward conductive block 153 on the left side of the forward electronic component 155 may be different from the height of the forward solder bump 150a under the forward conductive block 153 on the right side of the forward electronic component 155, thereby presenting a height difference between the top surfaces of the forward conductive blocks 153. In addition, the top surface of the forward conductive block 153 may also have a tilt problem. A pressing process may be performed to solve this problem.
[0031] like Figure 1F As shown, the package substrate 100 is loaded onto the second bottom mold 161, wherein the plurality of forward conductive blocks 153 face upward, and the forward conductive blocks 153 are pressed against the second bottom mold 161 by a second top mold 162 to reshape the forward solder bumps 150a. Figure 1FIn the illustrated embodiment, the second top mold 162 may include a second base plate 164 and a second flexible film 163, and the second flexible film 163 contacts the top surfaces of the plurality of forward conductive blocks 153 during the pressing step. The second flexible film 163 may serve as a slow-release film that provides a buffer zone between the second base plate 164 and the forward conductive blocks 153. After the pressing step, the top surfaces of the plurality of forward conductive blocks 153 are horizontally aligned with each other and the forward solder bumps 150a are reshaped but not connected to each other. The details of the pressing step are similar to those of FIG. Figure 1C The pressing steps shown are similar.
[0032] Then, if Figure 1G As shown in FIG. 1 , a forward mold cover 170 is formed between the package substrate 100 and the second top mold 162, and the forward mold cover 170 encapsulates a plurality of forward conductive blocks 153 and the at least one forward electronic component 155. The top surfaces of the plurality of forward conductive blocks 153 are exposed from the top surface of the forward mold cover 170. The detailed formation process of the forward mold cover 170 is similar to that of FIG. Figure 1D The formation process of the rear-facing mold cap 140 is similar. The second top mold 162 and the second bottom mold 161 can then be removed from the package substrate 100 and the various components thereon.
[0033] Then, if Figure 1H As shown, a shielding layer 171 is formed at least on the flat top surface of the forward mold cap 170, and the shielding layer 171 can help protect other parts of the electronic package components from electromagnetic interference. The shielding layer 171 above the top surface of the forward conductive block 153 is removed to expose the top surface of the forward conductive block 153 for mounting external electronic devices. In some embodiments, the shielding layer 171 may extend to other structures of the mold cap, and / or be adjacent to other surfaces (e.g., lateral surfaces) of the forward mold cap 170, or to the back mold cap 140 and the package substrate 100. In some embodiments, the package substrate 100 can be singulated into smaller units before or after the shielding layer 171 is formed. Next, a solder material is deposited on the top surfaces of the plurality of back conductive blocks 113 to form solder bumps 165 thereon for attaching other external electronic devices.
[0034] Then, if Fig. 1IAs shown, additional solder bumps 166 are formed on the upper surface of the forward conductive block 153. Then, the upper electronic component 180 can be mounted on the top surface of the forward conductive block 153 via the additional solder bumps 166 to form a three-layer electronic package assembly 190. In some embodiments, the upper electronic component 180 can be a pre-molded electronic package, which can be manufactured by the following process: providing an additional package substrate 181 with a forward surface, mounting at least one electronic component 182 on the forward surface of the additional package substrate 181, forming a mold cover 183 to encapsulate at least one electronic component 182; forming a shielding layer 184 on the top surface and side surfaces of the mold cover 183 or preventing electromagnetic interference. In some other embodiments, it can be understood that other various types of electronic modules can be mounted on the top surface of the forward conductive block 153.
[0035] exist Fig. 1I In the illustrated embodiment, the electronic package assembly 190 may include a double-sided molded (DSM) package, and the electronic package assembly 190 has conductive blocks and electronic components on two opposite surfaces of the package substrate 100. After two pressing steps, the top surfaces of the forward conductive blocks 153 are horizontally aligned with each other, and the top surfaces of the back conductive blocks 113 are horizontally aligned with each other, thereby allowing the uniformity of the conductive blocks on both sides of the package substrate 100 to be improved. Therefore, the top surface of the forward conductive block 153 and the top surface of the back conductive block 113 can both be used as a flat platform for mounting an external electronic module such as an upper electronic component 180, further improving the structural uniformity of the three-layer electronic package assembly 190 and reducing potential structural defects in subsequent processes.
[0036] Figures 2A to 2H The various steps of the method for forming an electronic packaging assembly according to the second embodiment of the present application are shown. Figures 2A to 2H The method is described in more detail.
[0037] like Figure 2A As shown, the package substrate 200 has embedded interconnection lines. The package substrate 200 includes a front surface 200a and a rear surface 200b opposite to each other. A plurality of groups of front conductive pads may be formed on the front surface 200a, and a plurality of groups of rear conductive pads may be formed on the rear surface 200b. It can be understood that the plurality of groups of front conductive pads and the rear conductive pads may be exposed portions of the interconnection lines formed in the package substrate 200.
[0038] like Figure 2BAs shown, the plurality of rear-facing conductive blocks 213 are attached to the rear-facing surface 200b of the package substrate 200 via rear-facing solder bumps 210a, and each of the plurality of rear-facing conductive blocks 213 is aligned with a group of rear-facing conductive pads in a plurality of groups of rear-facing conductive pads. The rear-facing conductive blocks 213 may be eBar blocks, each of which further includes a plurality of conductive pillars 211 and a dielectric layer 212 surrounding the plurality of conductive pillars 211. In addition, at least one rear-facing electronic component 215 is attached to the rear-facing surface 200b of the package substrate 200 via an additional solder bump 210b. The detailed formation process and structure of the rear-facing conductive blocks 213, the rear-facing solder bumps 210a, and the rear-facing electronic components 215 are similar to those of FIG. Figure 1B The formation process and structure of the rear-facing conductive mass 113, the rear-facing solder bump 110a and the rear-facing electronic component 115 shown in FIG.
[0039] Still refer to Figure 2B The back-facing conductive blocks 213 at different positions on the back-facing surface 200b of the package substrate 200 may have different heights. This is due to the different heights of the back-facing solder bumps 210a below the back-facing conductive blocks 213. A pressing process may be performed to solve this problem.
[0040] Then, if Figure 2C As shown, the packaging substrate 200 is loaded on the bottom mold 221, wherein the plurality of back-facing conductive block surfaces 213 face upward. The back-facing conductive blocks 213 are pressed against the bottom mold 221 using the top mold 230 to reshape the back solder bumps 210a. More specifically, the top mold 230 may include a base plate 232 and a flexible film 231, and the flexible film 231 contacts the top surfaces of the plurality of back-facing conductive blocks 213 during the pressing step. The flexible film 231 may be used as a slow-release film, which provides a buffer zone between the base plate 232 and the back-facing conductive blocks 213. After the pressing step, the top surfaces of the plurality of back-facing conductive blocks 213 are horizontally aligned with each other, which improves the uniformity of the structure of the back-facing conductive blocks 213. In addition, the back solder bumps 210a on each group of back-facing conductive pads are reshaped but are not connected to each other. In some other embodiments, Figure 2C The pressing step shown can also be omitted or performed later.
[0041] Then, if Figure 2DAs shown, the package substrate 200 and various components thereon can be removed from the top mold 230 and the bottom mold 221. The substrate 200 can then be flipped to further attach other components to the forward surface 200a of the substrate. Specifically, a plurality of forward solder bumps 250a can be formed on a plurality of groups of forward conductive pads. In addition, a plurality of forward conductive blocks 253 are also attached to the forward surface 200a of the package substrate 200 via the forward solder bumps 250a, and each forward conductive block 253 is aligned with one of the groups of forward conductive pads. The forward conductive block 253 can be an eBar block comprising a plurality of conductive pillars 251 and a dielectric layer 252 surrounding the plurality of conductive pillars 251. More specifically, the bottom surface of the conductive pillar 251 is exposed from the bottom surface of the dielectric layer 252 for contacting the forward solder bump 250a. Similarly, the top surface of the conductive pillar 251 is exposed from the top surface of the dielectric layer 252 for electrical connection of other devices. In addition, at least one forward electronic component 255 is attached to the forward surface 200a of the package substrate 200 through an additional solder bump 250b, and the forward conductive block 253 is higher than the forward electronic component 255. The detailed attachment process and structure of the forward conductive block 253, the forward solder bump 250a, and the forward electronic component 255 are similar to those of the forward conductive block 153, the forward solder bump 150a, and the forward electronic component 155. Figure 1E The attachment process and structure shown in are similar.
[0042] Still refer to Figure 2D , the forward conductive blocks 253 at different positions on the forward surface 200a of the package substrate 200 may have different heights, which is caused by the different heights of the forward solder bumps 250a under the forward conductive blocks 253. A pressing process may be performed to solve this problem.
[0043] like Figure 2E As shown, the package substrate 200 is loaded between the top mold 263 and the bottom mold 260. Next, the plurality of forward conductive blocks 253 and the plurality of rear conductive blocks 213 are pressed against the package substrate 200 by the top mold 263 and the bottom mold 260 to reshape the forward solder bumps 250a and the rear solder bumps 210a. After the pressing step, the top surfaces of the plurality of rear conductive blocks 213 are horizontally aligned with each other, and the top surfaces of the plurality of forward conductive blocks 253 are horizontally aligned with each other. More specifically, during the pressing process, the forward solder bump 250a can be greatly flattened, for example, from a circular shape to an elliptical shape or even a disc shape, thereby reducing the distance from the top surface of the forward conductive block 253 to the forward surface 200a of the package substrate 200 in a controllable manner. The amount of height reduction of the forward solder bump 250a can be different, depending on the original height of the forward solder bump 250a. In addition, since the upper surface facing away from the conductive block 213 is Figure 2C Already aligned during the previous pressing step shown, Figure 2E The pressing step in the process can continue to reduce the height of the back solder bump 210a to the same extent, thereby continuing to keep the top surfaces of the back conductive blocks 213 horizontally aligned with each other. In this way, the top surface of the forward conductive block 253 is aligned with the top surface of the back conductive block 213, respectively, so that the uniformity of the conductive blocks is better, and the pressing process is more reliable and flexible. In some embodiments, after the pressing step of the forward conductive block 253 and the back conductive block 213, the forward solder bumps 250a on each group of forward conductive pads are reshaped but not connected to each other, and the back solder bumps 210a on each group of back conductive pads are reshaped but not connected to each other. It can also be understood that if the back solder bumps 210a are Figure 2C The shape is reshaped after the pre-pressing step as shown, and the top surface facing away from the conductive block 213 can also be realigned during the pressing step.
[0044] In some other embodiments, Figure 2C The pressing step shown in FIG. 2 may not be performed before attaching the forward conductive block 253. Therefore, the back conductive blocks 213 at different positions on the back side 200b of the package substrate 200 may also have different heights due to the height difference of the back solder bumps 210a under the corresponding back conductive blocks 213. Figure 2E During the pressing step shown, the back solder bump 210a and the front solder bump 250a can be squeezed and flattened at the same time. The amount of reduction in the height of the back solder bump 210a can be different, depending on the original height of the back solder bump 210a; similarly, the amount of reduction in the height of the front solder bump 250a can also be different. According to this method, the distance from the top surface of the back conductive block 213 to the back surface 200b of the package substrate 200 and the distance from the top surface of the front conductive block 253 to the front surface 200a are reduced in a controllable manner, thereby simplifying the pressing process.
[0045] In addition, the top mold 263 may include a top base plate 265 and a top flexible film 264, and the top flexible film 264 contacts the top surfaces of the plurality of forward conductive blocks 253 during the pressing step. The top flexible film 264 may be used as a slow-release film, which provides a buffer zone between the top base plate 265 and the forward conductive blocks 253. Similarly, the bottom mold 260 may include a bottom base plate 262 and a bottom flexible film 261, and the bottom flexible film 261 contacts the top surfaces of the plurality of backward conductive blocks 213 during the pressing step. The bottom flexible film 261 may be used as a slow-release film, which provides a buffer zone between the bottom base plate 262 and the backward conductive blocks 213. In addition, Figure 2EThe top mold 263 and the bottom mold 260 used in the pressing step are shown with Figure 2C The top mold 230 and the bottom mold 221 used in the pressing step shown in FIG. 2 may be different. Figure 2E The top mold 263 and the bottom mold 260 used in the pressing step shown can also be used with Figure 2C The top mold 230 and the bottom mold 221 are shown to be identical, that is, the set of molds is used twice in the pressing step.
[0046] Then, if Figure 2F As shown, the front mold cover 270 is formed between the front surface 200a of the package substrate 200 and the top mold 262, and the front mold cover 270 encapsulates the side surfaces of the plurality of front conductive blocks 253 and the side surfaces and top surfaces of one or more front electronic components 255. Similarly, the back mold cover 240 is formed between the back surface 200b of the package substrate 200 and the bottom mold 260, and the back mold cover 240 encapsulates the side surfaces of the plurality of back conductive blocks 213 and the top surface and lateral surfaces of the back electronic components 215. The top surfaces of the plurality of front conductive blocks 253 are exposed from the top surface of the front mold cover 270, and the top surfaces of the plurality of back conductive blocks 213 are exposed from the top surface of the back mold cover 240. In some embodiments, the front mold cover 270 can be formed simultaneously with the back mold cover 240, simplifying the forming steps. In other embodiments, the front mold cover 270 can be formed before or after the back mold cover 240.
[0047] Further, in some embodiments, the front mold cover 270 and the back mold cover 240 are formed using a molding process, such as a film assisted molding (FAM) process. In some other embodiments, the front mold cover 270 and the back mold cover 240 can also be formed using other molding techniques. The detailed forming process of the front mold cover 270 and the back mold cover 240 can be the same as that of the embodiment of the present invention. Figure 1D and Figure 1G The forming process of the front mold cover 170 and the rear mold cover 140 shown are similar.
[0048] Then, if Figure 2GAs shown, a shielding layer 271 is formed at least on the flat top surface of the forward mold cap 270, and the shielding layer 271 can help protect other parts of the electronic package components from electromagnetic interference. The shielding layer 271 above the top surface of the forward conductive block 253 is removed to expose the top surface of the forward conductive block 253 for mounting external electronic devices. In some embodiments, the shielding layer 271 may extend to other structures of the mold cap, and / or be adjacent to other surfaces (e.g., lateral surfaces) of the forward mold cap 270, or to the back mold cap 240 and the package substrate 200. In some embodiments, the package substrate 200 can be singulated into smaller units before or after the shielding layer 271 is formed. Next, a solder material is deposited on the top surfaces of the plurality of back conductive blocks 213 to form solder bumps 265 thereon for attaching other external electronic devices.
[0049] Then, if Figure 2H As shown, an additional solder bump 266 is formed on the top surface of the forward conductive block 253. Then, the upper electronic component 280 can be mounted on the top surface of the forward conductive block 253 via the additional solder bump 266 to form a three-layer electronic package assembly 290. In some embodiments, the upper electronic component 280 can be a pre-molded electronic package, which can be manufactured by the following process: providing an additional package substrate 281 with a forward surface, mounting at least one electronic component 282 on the forward surface of the additional package substrate 281, forming a mold cover 283 to encapsulate the at least one electronic component 282; forming a shielding layer 284 on the top surface and side surfaces of the mold cover 283 to prevent electromagnetic interference. In some other embodiments, it can be understood that other various types of electronic modules can be mounted on the top surface of the forward conductive block 253.
[0050] In some embodiments, the electronic packaging assembly 290 can be applied to any electronic device that requires uniform structure and high yield, such as high-sensitivity sensors, precision integrated circuits and other devices.
[0051] It is understood that the process of pressing against solder bumps can be implemented in various other applications outside of semiconductor packaging. For example, the method may not include a process of attaching electronic components to the front and rear surfaces of the package substrate, whereby the process only forms conductive blocks on the front and rear surfaces of the package substrate. The top surfaces of the plurality of front conductive blocks are horizontally aligned with each other, and the top surfaces of the plurality of rear conductive blocks are also horizontally aligned with each other.
[0052] Although the exemplary method of forming an electronic package assembly of the present application is described in conjunction with the corresponding drawings, those skilled in the art will appreciate that modifications and adaptations may be made to the method of forming an electronic package assembly without departing from the scope of the present invention.
[0053] Various embodiments have been described herein with reference to the accompanying drawings. However, it will be apparent that various modifications and changes may be made to these embodiments, and additional embodiments may be implemented, without departing from the broader scope of the invention as set forth in the appended claims. In addition, other embodiments will be apparent to those skilled in the art by considering the specification and practice of one or more embodiments of the invention disclosed herein. Therefore, it is intended that the present application and the examples herein be considered merely exemplary, with the true scope and spirit of the invention being indicated by the enumeration of the appended exemplary claims.
Claims
1. A method for forming an electronic package assembly, characterized in that: The method comprises: Providing a packaging substrate having a front surface and a rear surface, wherein a plurality of groups of front conductive pads are formed on the front surface of the packaging substrate, and a plurality of groups of rear conductive pads are formed on the rear surface of the packaging substrate; attaching a plurality of rear-facing conductive blocks to the rear-facing surface of the package substrate via rear-facing solder bumps, wherein each of the rear-facing conductive blocks is aligned with a group of rear-facing conductive pads in the plurality of groups of rear-facing conductive pads; loading the package substrate onto a first bottom mold, with the plurality of rear-facing conductive blocks facing upward, and pressing the plurality of rear-facing conductive blocks against the first bottom mold using a first top mold so that the rear-facing solder bumps are reshaped and the top surfaces of the plurality of rear-facing conductive blocks are horizontally aligned with each other; forming a back-facing mold cover between the packaging substrate and the first top mold; attaching a plurality of forward conductive bumps to the front surface of the package substrate via forward solder bumps, wherein each of the forward conductive bumps is aligned with a group of forward conductive pads in the plurality of groups of forward conductive pads; loading the package substrate onto a second bottom mold with the plurality of forward conductive bumps facing upward, and pressing the plurality of forward conductive bumps against the second bottom mold with a second top mold to reshape the forward solder bumps and align top surfaces of the plurality of forward conductive bumps horizontally with each other; and A forward mold cap is formed between the package substrate and the second top mold.
2. The method according to claim 1, characterized in that Before loading the packaging substrate onto the first bottom mold, the method further includes: attaching at least one rear-facing electronic component to the rear-facing surface of the packaging substrate, wherein the plurality of rear-facing conductive blocks are higher than the rear-facing electronic component.
3. The method according to claim 1, characterized in that Before loading the package substrate onto the second bottom mold, the method further includes: attaching at least one front electronic component to the front surface of the package substrate, wherein the plurality of front conductive blocks are higher than the front electronic component.
4. The method according to claim 1, characterized in that: After forming the rear mold cap and forming the front mold cap, top surfaces of the plurality of front conductive blocks are exposed from a top surface of the front mold cap, and top surfaces of the plurality of rear conductive blocks are exposed from a top surface of the rear mold cap.
5. The method according to claim 1, characterized in that The forward conductive block and the rear conductive block are eBar blocks.
6. The method according to claim 1, characterized in that After pressing against the forward conductive block, the forward solder bumps on each group of forward conductive pads are reshaped but not connected to each other, and after pressing against the backward conductive block, the backward solder bumps on each group of backward conductive pads are reshaped but not connected to each other.
7. A method for forming an electronic package assembly, characterized in that: The method comprises: Providing a packaging substrate having a front surface and a rear surface, wherein a plurality of groups of front conductive pads are formed on the front surface of the packaging substrate, and a plurality of groups of rear conductive pads are formed on the rear surface of the packaging substrate; attaching a plurality of forward conductive bumps to the front surface of the package substrate via forward solder bumps, wherein each of the forward conductive bumps is aligned with a group of forward conductive pads in the plurality of groups of forward conductive pads; attaching a plurality of rear-facing conductive blocks to the rear-facing surface of the package substrate via rear-facing solder bumps, wherein each of the rear-facing conductive blocks is aligned with a group of rear-facing conductive pads in the plurality of groups of rear-facing conductive pads; loading the package substrate between a top mold and a bottom mold, and pressing the plurality of front conductive blocks and the plurality of rear conductive blocks against the package substrate using the top mold and the bottom mold, to reshape the front solder bump and the rear solder bump, and to align top surfaces of the plurality of front conductive bumps horizontally with each other, and to align top surfaces of the plurality of rear conductive bumps horizontally with each other; forming a forward mold cap between the front surface of the package substrate and the top mold; and A rear mold cover is formed between the rear surface of the package substrate and the bottom mold.
8. The method according to claim 7, characterized in that Before loading the packaging substrate between the top mold and the bottom mold, the method further includes: attaching at least one front electronic component to the front surface of the packaging substrate, the plurality of front conductive blocks being higher than the front electronic component.
9. The method according to claim 7, characterized in that: Before loading the packaging substrate between the top mold and the bottom mold, the method further includes: attaching at least one rear-facing electronic component to the rear-facing surface of the packaging substrate, the plurality of rear-facing conductive blocks being higher than the rear-facing electronic component.
10. The method according to claim 7, characterized in that Before attaching the plurality of front conductive blocks to the front surface of the packaging substrate, attaching the plurality of rear conductive blocks to the rear surface of the packaging substrate; Before attaching a plurality of forward conductive bumps to the front surface of the package substrate, the method further comprises: loading the package substrate onto a bottom mold, wherein the plurality of back-facing conductive blocks face upward; as well as The plurality of rearward conductive blocks are pressed against the bottom mold using a top mold to reshape the rearward solder bumps and to horizontally align top surfaces of the plurality of rearward conductive blocks with each other.
11. The method according to claim 7, characterized in that The top mold includes a top base plate and a top flexible film, and the top flexible film contacts the top surfaces of the plurality of forward conductive blocks during the pressing step.
12. The method according to claim 7, characterized in that The bottom mold includes a bottom base plate and a bottom flexible film, and the bottom flexible film contacts the top surfaces of the plurality of conductive blocks facing away from each other during the pressing step.
13. The method according to claim 7, characterized in that The forward conductive block and the rear conductive block are eBar blocks.
14. The method according to claim 7, characterized in that After the step of pressing against the forward conductive blocks and the rear conductive blocks, the forward solder bumps on each group of forward conductive pads and the rear solder bumps on each group of rear conductive pads are reshaped but not connected to each other.
15. The method according to claim 7, characterized in that The method further comprises: Solder material is deposited onto the top surface of the conductive block facing away from the top surface to form a solder bump thereon.
16. The method according to claim 7, characterized in that After forming the front mold cap and forming the rear mold cap, top surfaces of the plurality of front conductive blocks are exposed from a top surface of the front mold cap, and top surfaces of the plurality of rear conductive blocks are exposed from a top surface of the rear mold cap.
17. The method according to claim 16, characterized in that The method further comprises: An upper electronic component is mounted to the top surface of the plurality of forward conductive blocks.
18. The method according to claim 17, characterized in that The upper electronic component includes a pre-molded electronic package.
19. An electronic packaging assembly, characterized in that: The electronic package assembly is formed using the method according to any one of claims 1 to 18.