TWI732548B - Package structure - Google Patents

Abstract

A package structure is provided. The package structure includes a ball grid array (BGA) package, a printed circuit board (PCB), and an epoxy layer between the BGA package and the PCB. The PCB has at least an injection hole penetrating the PCB. Hence, an epoxy underfill can be injected into the space between the central region of the BGA package and the PCB through the injection hole and fill therein.

Description

Package structure

The invention relates to a packaging structure, in particular an epoxy resin layer is located in the space between a chip of the packaging structure and a printed circuit board.

Due to the trend toward increasing density of semiconductor chip packaging, fine pitch ball grid array (FBGA) packages have been developed to allow reduction of semiconductor package outlines and provide increased packaging density. Generally speaking, the FBGA package includes a semiconductor die with a lead frame, and the lead frame is mounted on the top surface of a printed circuit board (PCB). The semiconductor die has a plurality of bonding pads to electrically connect the lead frame. In addition, bonding wires are used to connect the bonding pads on the semiconductor die and the conductive pads on the lead frame. Conductive elements, such as solder balls, are connected to conductive lines on the PCB. The semiconductor die, lead frame and bonding wire are packaged with a packaging compound.

PCB manufacturers use Ball Grid Array (BGA) and other high-density array packages to reduce the board space required for specific products. In order to reduce the space on the circuit board, PCB manufacturers have used a smaller pitch of the solder ball pitch, that is, the pitch between the solder ball row and the solder ball column. In order to use these smaller pitches, PCB manufacturers need to use expensive technology to manufacture PCBs.

When PCB manufacturers have used smaller pitches between solder balls, the high heat generated must be removed. At present, the common heat dissipation method in the industry is to conduct heat to external metal and heat conduction media through metal radiators, heat pipe radiators, fans, graphene patches, metal sheets, and thermal pads, or let air convection heat dissipation. However, the heat dissipation effect of these heat dissipation methods is still poor.

The main purpose of the present invention is to provide a package structure that can add one or more injection holes on the PCB on the back of the BGA, so that the injection head of the automatic dispenser can inject epoxy resin from the injection hole to the vicinity of the BGA. In the space between the center and the PCB, and then spread out, it is easier for the epoxy resin to fill the space between the BGA and the PCB.

In addition, when the PCB is printed, if the front and back sides of the PCB must be connected to the BGA, the two BGAs can be designed to be placed in a staggered position, and the required injection holes are reserved on the PCB to facilitate the filling of the epoxy resin. . This method can facilitate the processing operation, and also allows the heat generated by the work on the front and back of the BGA to be isolated from each other without affecting each other.

In view of the above, a packaging structure is provided, which includes a first packaging module, a printed circuit board, and a first heat insulation layer. The first package module includes a first chip and a plurality of first conductive solder balls under the first chip. The printed circuit board includes a plurality of first pins on the first surface of the printed circuit board for electrically connecting the first conductive solder balls respectively. The first heat insulation layer is filled in the space between the first chip and the printed circuit board, wherein the first heat insulation layer includes an epoxy resin.

According to an embodiment, the first package module may be a ball grid array package (Ball-grid arrays; BGA).

According to another embodiment, the printed circuit board further includes at least one first injection hole, wherein the at least one first injection hole penetrates the printed circuit board, and the at least one first injection hole leads to a portion of the adjacent one Between these first conductive solder balls.

According to another embodiment, the interval width of each of the first conductive solder balls is fixed.

According to another embodiment, it further includes a second packaging module and a second heat insulation layer. The second package module includes a second chip and a plurality of second conductive solder balls under the second chip. Moreover, the printed circuit board further includes a plurality of second pins on the second surface of the printed circuit board for electrically connecting the second conductive solder balls respectively. The second heat insulation layer fills the space between the second chip and the printed circuit board, wherein the second heat insulation layer contains the epoxy resin.

According to another embodiment, the second package module may be a ball grid array package.

According to another embodiment, the printed circuit board further includes at least one second injection hole, wherein the at least one second injection hole penetrates the printed circuit board, and the at least one second injection hole leads to a portion of the adjacent Between the second conductive solder balls

According to another embodiment, the interval width of each of the second conductive solder balls is fixed.

The embodiments of the present invention are described in detail with the accompanying drawings. The drawings are simplified schematic diagrams, and only schematic structures or methods are used to illustrate the related elements and combinations of the present invention. Therefore, the elements shown in the figure are not drawn in proportion to the actual number, shape, and size of the actual implementation. Some size proportions and other related size proportions are exaggerated or simplified to provide a clearer description. The actual number, shape, or size ratio of the actual implementation can be optional design and configuration, and the detailed component layout may be more complicated.

FIG. 2 is a schematic diagram of the operation structure of a package structure according to an embodiment of the present invention. In Figure 2, the packaging structure 100 includes a first packaging module 120a, a printed circuit board 110, and a first epoxy resin layer 130a. The first package module 120a includes a first chip 122a and a plurality of first conductive solder balls 124a under the first chip 122a. The printed circuit board 110 includes a plurality of first pins 112 a on the first surface 110 a of the printed circuit board and at least one first injection hole 124 a penetrating the printed circuit board 110. The first pins 112a are used to electrically connect the first conductive solder balls 124a, and the at least one first injection hole 114a leads to a portion of the adjacent first conductive solder balls 124a. The first epoxy resin layer 130a is located between the first chip 120a and the printed circuit board 110 and part of the at least one first injection hole 114a. The first epoxy resin layer 130a uses a first syringe 150a to inject epoxy resin used as an underfill between the first chip 120a and the printed circuit board 110 through the at least one first injection hole 114a Fill the gap in the gap.

FIG. 2 is a schematic diagram of the operation architecture of a package structure according to another embodiment of the present invention. In Figure 2, in addition to the components of the package structure 100 shown in FIG. 1, the package structure 200 also includes a second package module 120b, which includes a second chip 122b and a plurality of components located under the second chip 122b. A second conductive solder ball 124b. Moreover, the printed circuit board 110 further includes a plurality of second pins 112b on the second surface 110b of the printed circuit board 110 and at least one second injection hole 114b penetrating the printed circuit board 110. The second pins 112b are used for electrically connecting the second conductive solder balls 124b, and the at least one second injection hole 114b leads to a portion of the adjacent second conductive solder balls 124b. The second epoxy resin layer 130b is located between the second chip 122b and the printed circuit board 110 and within the at least one second injection hole 114b. The second epoxy resin layer 130b uses a second syringe 150b to inject the epoxy resin used as an underfill between the second chip 120b and the printed circuit board 110 through the at least one second injection hole 114b Fill the gap in the gap.

Wherein, the first package module 120a and the second package module 120b can be, for example, a ball grid array package (Ball-grid arrays; BGA), such as a fine pitch ball grid array (FBGA) package, an ultra-fine pitch ball grid array (VFBGA) package, micro ball grid array (μBGA) package, or window ball grid array (WBGA) package, but not limited to this.

Based on the above, the present invention uses the characteristics of epoxy resin used for underfill to add one or more injection holes on the PCB on the back of the BGA, so that the injection head of the automatic dispenser can be ringed by the injection hole. Oxygen resin is injected into the space between the center of the BGA and the PCB, and then diffuses outward, making it easier for the epoxy resin to fill the space between the BGA and the PCB. In this way, the common incomplete filling problem of epoxy resin can be improved.

In addition, when the PCB is printed, if the front and back sides of the PCB must be connected to the BGA, the two BGAs can be designed to be placed in a staggered position, and the required injection holes are reserved on the PCB to facilitate the filling of the epoxy resin. . This method can facilitate the processing operation, and also allows the heat generated by the work on the front and back of the BGA to be isolated from each other without affecting each other.

Therefore, through the above-mentioned epoxy resin injection filling method, the heat generated by the chip in the BGA can be prevented from being transferred to and accumulated on the PCB. Therefore, the direction of thermal energy conduction can be controlled, and the thermal energy can be conducted to the outside in the shortest path to contact with the outside air, so as to prevent a large amount of thermal energy from accumulating in the package structure. As shown in Figure 4 below, perform related experiments with the NP Nano Module.

Next, perform related temperature test experiments with NP Nano Module. In this module, there is a PCIe slot on the PCB, and a μSSD with a SATA interface is inserted in the PCIe slot. The Iometer for testing is a set of software that measures I/O data of a single system and a cluster system's subsystems.

Table 1: Temperature test data of NP nano modules without heat sink. No heat sink PCIe uSSD Room temperature rises to 30℃ 59°C 53°C Let stand for 15 minutes at 30℃ 56°C 49°C Run Iometer at 30°C for 15 points 86°C 68°C 30°C to 70°C 92°C 83°C Let stand at 70℃ for 15 minutes 118°C 103°C Run Iometer at 70°C for 15 points 126°C 108°C

Table 2: Temperature test data of NP nano modules without heat sink but with epoxy resin. The epoxy resin used is commercially available epoxy resin. Glue (without heat sink) PCIe uSSD Room temperature rises to 30℃ 42°C 43°C Let stand for 15 minutes at 30℃ 40℃ 41℃ Run Iometer at 30°C for 15 points 57°C 57°C 30°C to 70°C 82°C 82°C Let stand at 70℃ for 15 minutes 86°C 86°C Run Iometer at 70°C for 15 points 94°C 96°C

Table 3: Temperature test data of NP nano module with stainless steel heat sink. Heat sink (stainless steel) PCIe uSSD Room temperature rises to 30℃ 50℃ 49°C Let stand for 15 minutes at 30℃ 48℃ 48℃ Run Iometer at 30°C for 15 points 75°C 76°C 30°C to 70°C 90°C 89°C Let stand at 70℃ for 15 minutes 104°C 106°C Run Iometer at 70°C for 15 points 105°C 106°C

Table 4: Temperature test data of NP nano module with aluminum heat sink. Heat sink (aluminum) PCIe uSSD Room temperature rises to 30℃ 46°C 45°C Let stand for 15 minutes at 30℃ 45°C 44°C Run Iomter at 30°C for 15 minutes 68°C 67°C 30°C to 70°C 86°C 86°C Let stand at 70℃ for 15 minutes 85°C 84°C Run Ioemter at 70°C for 15 minutes 94°C 94°C

Comparing Table 2-4, it can be seen that at an ambient temperature of 30°C, modules that only use epoxy resin encapsulation, regardless of whether they run the Iometer program, have better heat dissipation performance than modules that use stainless steel heat sinks, but are better than aluminum modules. The heat sink module is slightly worse. However, when the ambient temperature rises to 70°C, modules that only use epoxy resin encapsulation, regardless of whether they run the Iometer program, have a heat dissipation performance comparable to that of modules that use aluminum heat sinks. This result shows that the use of epoxy resin potting can effectively achieve the effect of heat dissipation.

100, 200: Package structure 110: printed circuit board 110a: First side 110b: Second side 112a: first pin 112b: second pin 114a: The first injection hole 114b: second injection hole 120a: The first package module 120b: second package module 122a: first chip 122b: second chip 124a: The first conductive solder ball 124b: second conductive solder ball 130a: The first epoxy layer 130b: The second epoxy layer 150a: first syringe 150b: second syringe

In order to make the above and other objectives, features, advantages and embodiments of the present invention more comprehensible, the description of the attached drawings is as follows: FIG. 1 is a schematic diagram of the operation architecture of a package structure according to an embodiment of the present invention. FIG. 2 is a schematic diagram of the operation architecture of a package structure according to another embodiment of the present invention.

100, 200: Package structure

110: printed circuit board

110a: First side

112a: first pin

114a: The first injection hole

120a: The first package module

122a: first chip

124a: The first conductive solder ball

130a: The first epoxy layer

150a: first syringe

Claims (7)

A packaging structure, comprising: a first packaging module, including: a first chip; and a plurality of first conductive solder balls located under the first chip; a printed circuit board, the printed circuit board including: A first pin located on the first surface of the printed circuit board, the first pins are respectively electrically connected to each of the first conductive solder balls; and at least one first injection hole penetrates the printed circuit Board and the at least one first injection hole leading to a portion between the adjacent first conductive solder balls; and a first heat insulation layer filled in between the first chip and the printed circuit board In the space, the first heat insulation layer contains an epoxy resin. The package structure according to claim 1, wherein the first package module includes a ball grid array package. The package structure according to claim 1, wherein the interval width of each of the first conductive solder balls is fixed. The package structure according to claim 1, further comprising: a second package module, including: a second chip; and a plurality of second conductive solder balls located under the second chip; the printed circuit board further includes : A plurality of second pins are located on the second surface of the printed circuit board, and the second pins are respectively electrically connected to each of the second conductive solder balls; and a second heat insulation layer is filled in In the space between the second chip and the printed circuit board, the second heat insulation layer contains the epoxy resin. The package structure according to claim 4, wherein the second package module includes a ball grid array package. The packaging structure according to claim 4, wherein the printed circuit board further includes at least one second injection hole, wherein the at least one second injection hole penetrates the printed circuit board, and the at least one second injection hole leads to a part Between the adjacent second conductive solder balls. The package structure according to claim 4, wherein the interval width of each of the second conductive solder balls is fixed.

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