2.5d micro-bump package structure and method of manufacturing the same

Abstract

The application provides a 2.5D micro-bump packaging structure and a preparation method thereof, and relates to the field of chip packaging. The 2.5D micro-bump packaging structure comprises a base material, a base wiring combination layer, a conductive base layer, a conductive bump, a first metal piece, a second metal piece, a stop conductive layer and a cap layer. The first metal piece and the second metal piece are arranged in a staggered manner around the conductive bump. The first metal piece and the second metal piece are both located between the stop conductive layer and the conductive base layer. The first metal piece is arranged in a spaced manner with the stop conductive layer. One end of the second metal piece is connected to the stop conductive layer, the other end is protruded towards the base material, and the second metal piece is arranged in a spaced manner with the conductive base layer. Compared with the prior art, the first metal piece and the second metal piece can improve the heat dissipation area, and thus improve the heat dissipation performance of the overall bump structure. In the welding process, the welding area of the solder can be improved, the welding strength can be improved, and the cracking or breaking phenomenon of the welding structure can be slowed down.

Description

Technical Field

[0001] This invention relates to the field of chip packaging, and more specifically, to a 2.5D microbump packaging structure and its fabrication method. Background Technology

[0002] With the rapid development of the semiconductor industry, flip-chip packaging structures are widely used. Flip-chip packaging utilizes bumps to electrically connect the chip and the substrate. In existing bump structures, the coefficients of thermal expansion (CTE) of the copper pillar bumps, substrate, and underfill adhesive may mismatch during soldering heating, or external forces such as mechanical impact and bending during use can cause stress on the solder joints. Furthermore, when solder paste is used as the soldering material, voids are prone to occur in the solder layer, leading to poor bonding and low solder strength. Therefore, excessive stress on the solder joints can easily cause cracking or breakage of the solder structure, thus affecting its electrical performance. Summary of the Invention

[0003] The purpose of this invention is to provide a 2.5D microbump packaging structure and a method for preparing the 2.5D microbump packaging structure, which can significantly improve the welding strength, effectively reduce the cracking or breakage of the welding structure, and thus ensure its electrical performance.

[0004] In one aspect, embodiments of the present invention provide a 2.5D microbump packaging structure, comprising: The substrate has a solder pad on one side surface; A substrate wiring assembly layer is disposed on one side surface of the substrate and electrically connected to the solder pad; A conductive substrate layer is disposed on the substrate wiring assembly layer and electrically connected to the substrate wiring assembly layer; Conductive bumps are disposed on the conductive substrate layer; A first metal component is disposed on the conductive substrate layer surrounding the conductive bump; The second metal component is spaced around the conductive bump and is offset from the first metal component. A stop conductive layer is disposed on the conductive bump and covers the second metal part, wherein the first metal part and the second metal part are both located between the stop conductive layer and the conductive substrate layer. The first metal part is spaced apart from the stop conductive layer, and one end of the second metal part is connected to the stop conductive layer, and the other end protrudes toward the substrate and is spaced apart from the conductive substrate layer. A welding cap layer is disposed on the stop conductive layer.

[0005] In an optional embodiment, a first pyrolytic adhesive layer is provided at the end of the first metal part away from the stop conductive layer. The first metal part is bonded and fixed to the conductive substrate layer by the first pyrolytic adhesive layer. The first pyrolytic adhesive layer is configured to melt at a welding temperature so that the first metal part is detached from the conductive substrate layer.

[0006] In an optional embodiment, the second metal member surrounds the conductive bump, and a receiving groove is formed between the second metal member and the sidewall of the conductive bump. The first metal member corresponds to the receiving groove and is configured to fall into the receiving groove after detaching from the conductive substrate layer.

[0007] In an alternative embodiment, the first metal part extends into the receiving groove.

[0008] In an optional embodiment, the protrusion height of the second metal member relative to the conductive substrate is less than the length of the first metal member in the same direction, so that the first metal member and the second metal member form a stepped structure after falling into the receiving groove.

[0009] In an optional embodiment, one end of the first metal member away from the stop conductive layer is connected to the conductive substrate layer, and the other end protrudes toward the stop conductive layer, and the protrusion height of the first metal member is less than the protrusion height of the second metal member.

[0010] In an optional embodiment, the weld cap layer is in the form of a rectangular block.

[0011] In an optional embodiment, the edges of the solder cap layer, the stop conductive layer, and the conductive substrate layer are flush.

[0012] In an optional embodiment, the substrate wiring combination layer includes a first dielectric layer, a second dielectric layer, and a wiring layer. The first dielectric layer covers one side surface of the substrate and exposes the solder pads. The wiring layer is disposed on the first dielectric layer and is electrically connected to the solder pads. The second dielectric layer is disposed on the first dielectric layer and partially covers the wiring layer. The conductive substrate layer is disposed on the second dielectric layer and is electrically connected to the wiring layer. The conductive substrate layer is staggered from the solder pads.

[0013] In an optional embodiment, the materials of both the stop conductive element and the conductive bump include at least one of copper, gold, and silver.

[0014] In an optional embodiment, the 2.5D microbump packaging structure further includes a third metal component disposed on the conductive substrate layer surrounding the conductive bump and located between the stop conductive layer and the conductive substrate layer. The third metal component is disposed between the first metal component and the conductive bump and is spaced apart from the stop conductive layer.

[0015] In an optional embodiment, a second pyrolytic adhesive layer is provided at the end of the third metal part away from the stop conductive layer. The third metal part is bonded and fixed to the conductive substrate by the second pyrolytic adhesive layer. The second pyrolytic adhesive layer is configured to melt at a welding temperature so that the third metal part detaches from the conductive substrate layer and a heat dissipation gap is formed between the third metal part and the conductive substrate layer.

[0016] On the other hand, embodiments of the present invention provide a method for fabricating a 2.5D microbump encapsulation structure, used to fabricate the aforementioned 2.5D microbump encapsulation structure, the fabrication method comprising: A substrate is provided, wherein a solder pad is provided on one side surface of the substrate; A substrate wiring assembly layer is formed on one side surface of the substrate, wherein the substrate wiring assembly layer is electrically connected to the solder pad; A conductive substrate layer is formed on the substrate wiring assembly layer, wherein the conductive substrate layer is electrically connected to the substrate wiring assembly layer. A first metal element is formed on the conductive substrate layer; A conductive bump and a second metal member are formed on the conductive substrate layer, wherein the first metal member is located around the conductive bump, and the second metal member is spaced around the conductive bump and offset from the first metal member. A stop conductive layer is formed on the conductive bump, wherein the stop conductive layer covers the second metal part, and both the first metal part and the second metal part are located between the stop conductive layer and the conductive substrate layer. The first metal part is spaced apart from the stop conductive layer, and one end of the second metal part is connected to the stop conductive layer, while the other end protrudes toward the substrate and is spaced apart from the conductive substrate layer. A solder cap layer is formed on the stop conductive layer.

[0017] In an optional embodiment, the step of forming the first metal element on the conductive substrate layer includes: A first photoresist layer is formed on the conductive substrate layer; A groove is formed by cutting a groove in the first photoresist layer; A first metal part is formed by electroplating in the first groove; Remove the first photoresist layer.

[0018] In an optional embodiment, the step of forming conductive bumps and a second metal element on the conductive substrate layer includes: A second photoresist layer is formed on the conductive substrate layer; A groove is formed on the second photoresist layer to form a bump window exposing the conductive substrate layer and a second groove spaced apart from the conductive substrate layer, wherein the second groove is located around the bump window and the first metal member is located between the bump window and the second groove; Conductive bumps and second metal parts are electroplated in the bump window and the second groove, respectively, wherein the first metal part is located around the conductive bump, and the second metal part is spaced around the conductive bump and offset from the first metal part.

[0019] The beneficial effects of the embodiments of the present invention include: The 2.5D microbump packaging structure and its fabrication method provided in this invention involve forming a substrate wiring assembly layer on the surface of a substrate with solder pads, and then forming a conductive substrate layer on the substrate wiring assembly layer. Conductive bumps are formed on the conductive substrate layer, and a first metal component and a second metal component are staggered around the conductive bumps. A stop conductive layer is formed on the conductive bumps and covers the second metal component, and a solder cap layer is formed on the stop conductive bumps. Both the first and second metal components are located between the stop conductive layer and the conductive substrate layer. The first metal component is spaced apart from the stop conductive layer, and one end of the second metal component is connected to the stop conductive layer, while the other end protrudes towards the substrate and is spaced apart from the conductive substrate layer.

[0020] Compared to existing technologies, this invention, through the additional design of the first and second metal components, can increase the heat dissipation area, thereby improving the overall heat dissipation performance of the bump structure. Furthermore, during the welding process, the solder can laterally climb and contact the first and second metal components, thus increasing the welding area and enhancing the welding strength, mitigating cracking or breakage of the welded structure. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the 2.5D microbump packaging structure provided in the first embodiment of the present invention; Figure 2This is a partial structural schematic diagram of the 2.5D microbump packaging structure provided in the first embodiment of the present invention; Figure 3 This is a schematic diagram of the 2.5D microbump welding module provided in the first embodiment of the present invention before welding; Figure 4 This is a schematic diagram of the structure of the 2.5D microbump welding module provided in the first embodiment of the present invention after welding; Figure 5 This is a schematic diagram of the structure corresponding to step S1 in the fabrication method of the 2.5D microbump encapsulation structure provided in the first embodiment of the present invention; Figure 6 This is a schematic diagram of the structure corresponding to step S2 in the fabrication method of the 2.5D microbump encapsulation structure provided in the first embodiment of the present invention; Figure 7 This is a schematic diagram of the structure corresponding to step S3 in the fabrication method of the 2.5D microbump encapsulation structure provided in the first embodiment of the present invention; Figure 8 This is a schematic diagram of the structure corresponding to step S4 in the fabrication method of the 2.5D microbump encapsulation structure provided in the first embodiment of the present invention; Figure 9 This is a schematic diagram of the structure corresponding to step S5 in the method for preparing the 2.5D microbump encapsulation structure provided in the first embodiment of the present invention; Figure 10 This is a schematic diagram of the structure corresponding to step S6 in the method for preparing the 2.5D microbump encapsulation structure provided in the first embodiment of the present invention; Figure 11 This is a schematic diagram of the 2.5D microbump packaging structure provided in the second embodiment of the present invention; Figure 12 A partial structural schematic diagram of the 2.5D microbump packaging structure provided in the second embodiment of the present invention; Figure 13 This is a schematic diagram of the structure of the 2.5D microbump welding module provided in the second embodiment of the present invention; Figure 14 A schematic diagram of the 2.5D microbump packaging structure provided in the third embodiment of the present invention; Figure 15 A partial structural schematic diagram of the 2.5D microbump packaging structure provided in the third embodiment of the present invention; Figure 16 This is a schematic diagram of the structure of the 2.5D microbump welding module provided in the third embodiment of the present invention before welding; Figure 17 This is a schematic diagram of the structure of the 2.5D microbump welding module after welding, as provided in the third embodiment of the present invention.

[0023] Icons: 100-2.5D microbump packaging structure; 110-substrate; 111-solder pad; 120-substrate wiring assembly layer; 121-first dielectric layer; 122-second dielectric layer; 123-wiring layer; 130-conductive substrate layer; 140-conductive bump; 150-first metal component; 151-first pyrolytic adhesive layer; 160-second metal component; 161-receiving groove; 170-stop conductive layer; 180-solder cap layer; 190-third metal component; 191-second pyrolytic adhesive layer; 200-first photoresist layer; 210-first groove; 300-second photoresist layer; 310-second groove; 320-bump window; 400-2.5D microbump soldering module; 410-substrate; 420-intermediate layer; 430-metal ring. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0028] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0029] As disclosed in the background section, in existing bump structures, the solder joints are subjected to stress due to mismatches in the coefficients of thermal expansion (CTE) of the copper pillar bumps, substrate, and underfill adhesive during soldering, or due to external forces such as mechanical impact and bending during use. Excessive stress on the solder joints can easily lead to cracking or breakage of the solder structure, thus affecting its electrical performance. Furthermore, when solder paste is used as the soldering material, voids are prone to occur in the solder layer, resulting in poor bonding and low solder strength. Moreover, as a conductive material for soldering, solder paste only conducts electricity through the solder layer or only through the bumps to achieve electrical connection, resulting in poor conductivity.

[0030] To address the aforementioned problems, embodiments of the present invention provide a 2.5D microbump encapsulation structure and its fabrication method. It should be noted that, unless otherwise specified, features in the embodiments of the present invention can be combined with each other.

[0031] First Embodiment See Figure 1 and Figure 2 The present invention provides a 2.5D microbump packaging structure 100, which can significantly improve the welding strength, effectively reduce the cracking or breakage of the welding structure, and thus ensure its electrical performance.

[0032] The 2.5D microbump packaging structure 100 provided in this embodiment of the invention includes a substrate 110, a substrate wiring assembly layer 120, a conductive substrate layer 130, conductive bumps 140, a first metal component 150, a second metal component 160, a stop conductive layer 170, and a solder cap layer 180. A solder pad 111 is disposed on one side surface of the substrate 110. The substrate wiring assembly layer 120 is disposed on one side surface of the substrate 110 and electrically connected to the solder pad 111. The conductive substrate layer 130 is disposed on and electrically connected to the substrate wiring assembly layer 120. The conductive bumps 140 are disposed on the conductive substrate layer 130. The first metal component 150 is disposed on the conductive substrate layer 130 surrounding the conductive bumps 140. The second metal component 160 is spaced around the conductive bumps 140 and offset from the first metal component 150. A stop conductive layer 170 is disposed on the conductive bump 140 and covers the second metal part 160. Both the first metal part 150 and the second metal part 160 are located between the stop conductive layer 170 and the conductive substrate layer 130. The first metal part 150 is spaced apart from the stop conductive layer 170. One end of the second metal part 160 is connected to the stop conductive layer 170, and the other end protrudes towards the substrate 110 and is spaced apart from the conductive substrate layer. A solder cap layer 180 is disposed on the stop conductive layer 170.

[0033] It should be noted that the substrate 110 in this embodiment of the invention can be a base chip or a substrate chip. By additionally designing the first metal part 150 and the second metal part 160, the heat dissipation area can be increased, thereby improving the heat dissipation performance of the overall bump structure. Furthermore, during the soldering process, the solder can laterally climb and contact the first metal part 150 and the second metal part 160, thereby increasing the soldering area, thus improving the soldering strength and mitigating cracking or breakage of the soldered structure.

[0034] Furthermore, a first pyrolytic adhesive layer 151 is provided at the end of the first metal part 150 away from the stop conductive layer 170. The first metal part 150 is bonded and fixed to the conductive substrate layer 130 by the first pyrolytic adhesive layer 151. The first pyrolytic adhesive layer 151 is configured to melt at the welding temperature, so that the first metal part 150 detaches from the conductive substrate layer 130. Specifically, the first pyrolytic adhesive layer 151 can be made of a pyrolytic adhesive material, which softens and melts at a temperature of 120-180°C (lower than the welding temperature), and the adhesive force disappears, causing the first metal part 150 to fall to the stop conductive layer 170 under gravity.

[0035] Furthermore, the second metal member 160 is disposed around the conductive bump 140, and a receiving groove 161 is formed between the second metal member 160 and the sidewall of the conductive bump 140. The first metal member 150 corresponds to the receiving groove 161 and is configured to fall into the receiving groove 161 after detaching from the conductive substrate layer 130. Specifically, the second metal member 160 may be disposed in an annular shape around the conductive bump 140 and spaced apart from the sidewall of the conductive bump 140, thereby forming the receiving groove 161. When the first metal member 150 falls, it can fall directly into the receiving groove 161, thereby preventing the first metal member 150 from falling further into the solder below.

[0036] In this embodiment, the first metal part 150 extends into the receiving groove 161. Specifically, the end of the first metal part 150 away from the first pyrolytic adhesive layer 151 extends into the receiving groove 161, so that when it falls, the first metal part 150 can directly fall into the receiving groove 161, ensuring the accuracy of the fall.

[0037] In this embodiment, the protrusion height of the second metal part 160 relative to the conductive substrate layer 130 is less than the length of the first metal part 150 in the same direction, so that the first metal part 150 and the second metal part 160 form a stepped structure after falling into the receiving groove 161. Specifically, the first metal part 150 that falls into the receiving groove 161 extends out of the receiving groove 161, thereby forming a stepped structure at the end faces of the first metal part 150 and the second metal part 160. This can enhance the capillary action of the solder and increase the contact area of ​​the solder during welding, thereby improving the solder bonding force and welding effect.

[0038] It should be noted that in this embodiment, there can be multiple first metal parts 150. These multiple first metal parts 150 are arranged around the conductive bump 140, and after falling off, they can be spaced out in the receiving groove 161, thereby forming multiple stepped structures. The receiving groove 161 that is not filled by the first metal parts 150 can serve as a gap to accommodate solder, further improving the bonding strength of the solder.

[0039] In this embodiment, the solder cap layer 180 is rectangular. Specifically, the solder cap layer 180 can be a tin layer, which can be rectangular to form a microbump structure. The tin layer can use a low-melting-point solder, such as In-based, SnIn, SnBiSnAg, etc., and the microbump structure is formed by low-temperature reflow. The microbump low-temperature reflow process achieves the melting of microbumps in the range of 140–180℃.

[0040] In this embodiment, the edges of the solder cap layer 180, the stop conductive layer 170, and the conductive base layer 130 are flush. Specifically, the solder cap layer 180, the stop conductive layer 170, and the conductive base layer 130 have the same width, making their edges flush, while the first metal member 150 and the second metal member 160 can be confined between the stop conductive layer 170 and the conductive base layer 130.

[0041] In this embodiment, the materials of the stop conductive layer 170 and the conductive bump 140 both include at least one of copper, gold, and silver. Preferably, the first metal part 150, the second metal part 160, and the conductive bump 140 are all made of copper. The second metal part 160 is a copper fence, and the first metal part 150 is a thin copper pillar, which is evenly distributed around the conductive bump 140. The conductive bump 140 is a copper pillar bump, which has excellent conductivity.

[0042] In this embodiment, the substrate wiring assembly layer 120 includes a first dielectric layer 121, a second dielectric layer 122, and a wiring layer 123. The first dielectric layer 121 covers one side surface of the substrate 110 and exposes the solder pads 111. The wiring layer 123 is disposed on the first dielectric layer 121 and electrically connected to the solder pads 111. The second dielectric layer 122 is disposed on the first dielectric layer 121 and partially covers the wiring layer 123. A conductive substrate layer 130 is disposed on the second dielectric layer 122 and electrically connected to the wiring layer 123. The conductive substrate layer 130 and the solder pads 111 are staggered. Specifically, the first dielectric layer 121 and the second dielectric layer 122 are both dielectric materials, the wiring layer 123 can be a copper layer, and the solder pads 111 and the conductive substrate layer 130 are staggered.

[0043] In this embodiment, the stop conductive layer 170 includes a first metal layer and a second metal layer. The first metal layer is connected to the conductive bump 140, and the second metal layer is disposed on the first metal layer. The solder cap layer 180 is disposed on the second metal layer. The first metal layer can be a copper layer, which serves a wetting function, enhancing the adhesion between the first metal layer and the conductive bump 140 and the connecting conductive component. The second metal layer can be a nickel layer, ensuring conductivity while effectively mitigating atomic migration.

[0044] See Figure 3 and Figure 4 This invention also provides a 2.5D microbump soldering module 400, including a substrate 410, an interposer 420, and a 2.5D microbump package structure 100 as described above. The interposer 420 is soldered and fixed to the substrate 410, and the 2.5D microbump package structure 100 is flip-chip soldered to the interposer 420. Solder bumps and solder wiring structures are provided on the bottom side of the interposer 420. The solder bumps can be soldered and fixed to pads on the substrate 410, and a protective adhesive layer is formed by dispensing adhesive. Simultaneously, a transition pad is provided on the top side of the interposer 420, and the transition pad and the solder wiring structure on the bottom side are vertically interconnected via a TSV structure. The 2.5D microbump package structure 100 is correspondingly soldered to the transition pad. The solder cap layer 180 melts during soldering, and the molten solder can laterally climb to the vicinity of the conductive bump 140. Meanwhile, the first pyrolytic adhesive layer 151 softens and melts at the soldering temperature, losing its adhesive strength. This causes the first metal part 150 to fall under gravity into the receiving groove 161 formed by the second metal part 160, creating a stepped structure between the first metal part 150 and the second metal part 160. The solder can continue to laterally climb and cover the first metal part 150 and the second metal part 160 under capillary action, increasing the contact area of ​​the solder and thus improving the solder bonding strength and soldering effect. Simultaneously, the conductive bump 140 is soldered to the corresponding transition pads on the interposer layer 420, and protection is achieved after soldering through the adhesive layer formed by dispensing.

[0045] Furthermore, a metal ring 430 is also provided on the substrate 410, which surrounds the interposer layer 420 and the 2.5D microbump package structure 100 to achieve protection and heat dissipation functions.

[0046] This invention also provides a method for fabricating a 2.5D microbump encapsulation structure 100, which includes the following steps: S1: Provide a substrate 110, wherein a solder pad 111 is provided on one side surface of the substrate 110.

[0047] See also Figure 5Specifically, a substrate 110 can be taken first. The substrate 110 can be a wafer with a base chip or a substrate chip, and an aluminum bonding pad 111 is formed on one side surface of the substrate 110. Electrical connection is achieved through the bonding pad 111.

[0048] S2: A substrate wiring assembly layer 120 is formed on one side surface of the substrate 110, wherein the substrate wiring assembly layer 120 is electrically connected to the solder pad 111.

[0049] See also Figure 6 Specifically, a liquid dielectric layer can be uniformly coated onto the surface of the substrate 110 using a spin coating machine to form a first dielectric layer 121. This is then set by a hot plate and exposed to light. Next, a photomask is used in a proximity method to expose predetermined positions on the first dielectric layer 121. Unexposed areas are removed by spraying developer to expose the openings of the aluminum solder pads 111. Finally, an oven is used to accelerate the curing of the first dielectric layer 121 to a fully matured and stable state. An electrolytic plating machine is then used to remove organic contaminants from the surface of the first dielectric layer 121 or residues within the openings, completing the process of exposing the solder pads 111. The first dielectric layer 121 can be composed of a polymer dielectric material, such as epoxide or polyimide phenylcyclobutene. A photoresist layer is then coated onto the surface of the first dielectric layer 121, and patterned grooves are created. Finally, a copper layer is sputtered into the grooves using a sputtering / electroplating process to form the RDL wiring layer 123. The organic contaminants on the RDL circuit surface are removed again using a plasma desmearing machine. The dielectric layer is then applied by a rotary coating process to form the second dielectric layer 122. The wiring layer 123 is exposed by slotting the second dielectric layer 122. The dielectric layer is then heated in an oven to accelerate its curing to a fully mature and stable state.

[0050] S3: A conductive substrate layer 130 is formed on the substrate wiring assembly layer 120, wherein the conductive substrate layer 130 is electrically connected to the substrate wiring assembly layer 120.

[0051] See also Figure 7 Specifically, a copper layer can be sputtered onto the surface of the second dielectric layer 122 using a sputtering / electroplating process. The conductive substrate layer 130 can be a UBM layer, and its material is at least one of Ti / Cu / Ni / Au. The conductive substrate layer 130 can be directly electrically connected to the wiring layer 123.

[0052] S4: A first metal element 150 is formed on the conductive substrate layer 130.

[0053] See also Figure 8Specifically, a first photoresist layer 200 can be formed on the conductive substrate layer 130, wherein the first photoresist layer 200 can cover the conductive substrate layer 130. Then, a first groove 210 is formed by slotting in the first photoresist layer 200. The slots can be formed at predetermined positions of the first photoresist layer 200 by photolithography, forming a discontinuously distributed annular first groove 210, wherein the first groove 210 can expose the conductive substrate layer 130. Then, a first metal part 150 is formed by electroplating in the first groove 210. Specifically, a first pyrolytic adhesive layer 151 can be formed in the first groove 210 first, and then the first metal part 150 can be formed by electroplating, so that the first metal part 150 is fixed on the conductive substrate layer 130 by the first pyrolytic adhesive layer 151. Finally, the first photoresist layer 200 can be removed.

[0054] S5: Conductive bumps 140 and a second metal part 160 are formed on the conductive substrate layer 130, wherein the first metal part 150 is located around the conductive bumps 140, and the second metal part 160 is spaced around the conductive bumps 140 and is offset from the first metal part 150.

[0055] See Figure 9 Specifically, after the fabrication of the first metal component 150 is completed, a second photoresist layer 300 can be formed on the conductive substrate layer 130. The second photoresist layer 300 can completely cover the first metal component 150, that is, the thickness of the second photoresist layer 300 is greater than the protrusion height of the first metal component 150. Then, grooves are cut in the second photoresist layer 300 to form a bump window 320 exposing the conductive substrate layer 130 and a second groove 310 spaced apart from the conductive substrate layer 130. The second groove 310 is located around the bump window 320, and the first metal component 150 is located between the bump window 320 and the second groove 310. Then, conductive bumps 140 and second metal components 160 are electroplated in the bump window 320 and the second groove 310, respectively. The first metal component 150 is located around the conductive bump 140, and the second metal components 160 are spaced apart around the conductive bump 140 and offset from the first metal component 150.

[0056] It should be noted that the second groove 310 does not expose the conductive substrate layer 130, thus separating the second metal part 160 from the conductive substrate layer 130. In actual fabrication, a photolithography process can be used to pattern the second photoresist layer 300, thereby forming the bump window 320 and the second groove 310. The second groove 310 is arranged in a ring around the bump window 320 and is separated from the bump window 320 by the first metal part 150. Finally, an electroplating process can be used to simultaneously form metal layers in the bump window 320 and the second groove 310, thus simultaneously forming the conductive bump 140 and the second metal part 160. The first metal part 150 is located between the second metal part 160 and the conductive bump 140, and the top of the second metal part 160 is flush with the second photoresist layer 300, with the top of the first metal part 150 confined within the second photoresist layer 300.

[0057] S6: A stop conductive layer 170 is formed on the conductive bump 140.

[0058] See Figure 10 The stop conductive layer 170 covers the second metal part 160, and the first metal part 150 and the second metal part 160 are both located between the stop conductive layer 170 and the conductive substrate layer 130. The first metal part 150 is spaced apart from the stop conductive layer 170. One end of the second metal part 160 is connected to the stop conductive layer 170, and the other end protrudes toward the substrate 110 and is spaced apart from the conductive substrate layer.

[0059] Specifically, after forming the conductive bump 140, a metal layer, which can be a copper / nickel layer, can be formed on the conductive bump 140 using an electroplating process to form the stop conductive layer 170. Then, a photoresist stripping process is used to remove residual photoresist, and a plasma stripper is used to remove residues from the dielectric layer. Finally, an etching process (plasma etching or chemical etching) is used to remove excess conductive substrate layer 130. The stop conductive layer 170 covers the second metal part 160 and the conductive bump 140, allowing the stop conductive layer 170 to be directly electrically connected to the second metal part 160 and the conductive bump 140.

[0060] S7: A solder cap layer 180 is formed on the stop conductive layer 170.

[0061] Please continue reading Figure 1 Specifically, the electroplating ball-planting process can be reused, and a formic acid reflow process can be used to form a bump-shaped solder cap layer 180.

[0062] In summary, the 2.5D microbump packaging structure 100 and its fabrication method provided in this embodiment of the invention involve forming a substrate wiring assembly layer 120 on one side of the substrate 110 where solder pads 111 are provided, and placing a conductive substrate layer 130 on the substrate wiring assembly layer 120. Conductive bumps 140 are placed on the conductive substrate layer 130, and a first metal element 150 and a second metal element 160 are staggered around the conductive bumps 140. A stop conductive layer 170 is placed on the conductive bumps 140 and covers the second metal element 160, and a solder cap layer 180 is placed on the stop conductive bumps. The first metal element 150 and the second metal element 160 are both located between the stop conductive layer 170 and the conductive substrate layer 130. The first metal element 150 is spaced apart from the stop conductive layer 170, and one end of the second metal element 160 is connected to the stop conductive layer 170, while the other end protrudes towards the substrate 110 and is spaced apart from the conductive substrate layer. Compared to existing technologies, this invention, through the additional design of the first metal part 150 and the second metal part 160, can increase the heat dissipation area, thereby improving the overall heat dissipation performance of the bump structure. Furthermore, during the welding process, the solder can laterally climb and contact the first metal part 150 and the second metal part 160, thereby increasing the welding area of ​​the solder, thus improving the welding strength and mitigating cracking or breakage of the welded structure.

[0063] Second Embodiment See Figure 11 and Figure 12 This invention provides a 2.5D microbump packaging structure 100, whose basic structure, principle and technical effects are the same as those of the first embodiment. For the sake of brevity, any parts not mentioned in this embodiment can be referred to the corresponding content in the first embodiment.

[0064] In this embodiment, a first metal member 150 is disposed on a conductive base layer 130 surrounding the conductive bump 140. A second metal member 160 is disposed at a distance around the conductive bump 140 and is offset from the first metal member 150. Specifically, one end of the first metal member 150, away from the stop conductive layer 170, is connected to the conductive base layer 130, and the other end protrudes towards the stop conductive layer 170, with the protrusion height of the first metal member 150 being less than the protrusion height of the second metal member 160. The first metal member 150 is connected to the conductive base layer 130 and protrudes towards the stop conductive layer 170, while the first metal member 150 and the stop conductive layer 170 are spaced apart. The second metal member 160 is connected to the stop conductive layer 170 and protrudes towards the conductive base layer 130, while the second metal member 160 and the conductive base layer 130 are spaced apart.

[0065] In the actual fabrication of the first metal part 150, it can be directly electroplated in the first groove 210 to form the first metal part 150, so that the first metal part 150 is in direct contact with the conductive substrate layer 130. In the formation of the second metal part 160, it can be electroplated in the second groove 310, and the bottom wall of the second groove 310 is located above the top of the first metal part 150, ensuring that the formed second metal part 160 is staggered and spaced apart from the first metal part 150.

[0066] It should be noted that the second metal component 160 and the first metal component 150 are staggered, creating a gap between them. During welding, by controlling the total amount of solder, the second metal component 160 can act as an external dam, preventing external solder from entering its interior. Simultaneously, during adhesive dispensing, the adhesive layer can penetrate the gap between the first metal component 150 and the second metal component 160, significantly improving the adhesive's bonding strength. This effectively protects the welded structure, mitigating cracking or breakage and ensuring its electrical performance. Alternatively, a larger amount of solder can be used, allowing it to laterally spread into the gap between the first metal component 150 and the second metal component 160, further increasing the welding area and strength.

[0067] Furthermore, in this embodiment of the invention, the first metal component 150 can be disposed close to the conductive bump 140 and surround the conductive bump 140, thereby providing impact protection, improving structural strength, and effectively preventing the conductive bump 140 from breaking. Moreover, by providing the first metal component 150, the heat dissipation area of ​​the overall bump structure can be increased, thereby improving heat dissipation performance.

[0068] See Figure 13This invention also provides a 2.5D microbump soldering module 400, including a substrate 410, an interposer 420, and a 2.5D microbump package structure 100 as described above. The interposer 420 is soldered and fixed to the substrate 410, and the 2.5D microbump package structure 100 is flip-chip soldered to the interposer 420. Solder bumps and solder wiring structures are provided on the bottom side of the interposer 420. The solder bumps can be soldered and fixed to pads on the substrate 410, and a protective adhesive layer is formed by dispensing adhesive. Simultaneously, a transition pad is provided on the top side of the interposer 420, and the transition pad and the solder wiring structure on the bottom side are vertically interconnected via a TSV structure. The 2.5D microbump package structure 100 is correspondingly soldered to the transition pad. The solder cap layer 180 can melt during welding. The molten solder can be blocked by the second metal part 160 forming a barrier. After dispensing, the adhesive layer enters the gap between the first metal part 150 and the second metal part 160, thereby significantly improving the adhesion of the adhesive layer and effectively protecting the welded structure. At the same time, the conductive bumps 140 are correspondingly welded to the transition pads on the interposer layer 420. After welding, protection can be achieved by the adhesive layer formed by dispensing.

[0069] Third Embodiment See Figure 14 and Figure 15 This invention provides a 2.5D microbump packaging structure 100, whose basic structure, principle and technical effects are the same as those of the first embodiment. For the sake of brevity, any parts not mentioned in this embodiment can be referred to the corresponding content in the first embodiment.

[0070] In this embodiment, a first metal component 150 is disposed on a conductive base layer 130 surrounding the conductive bump 140. A second metal component 160 is disposed at intervals around the conductive bump 140 and is offset from the first metal component 150. A first pyrolytic adhesive layer 151 is disposed at the end of the first metal component 150 away from the stop conductive layer 170. The first metal component 150 is bonded and fixed to the conductive base layer 130 by the first pyrolytic adhesive layer 151, which is configured to melt at a welding temperature to detach the first metal component 150 from the conductive base layer 130.

[0071] Furthermore, the 2.5D microbump packaging structure 100 also includes a third metal component. The third metal component is disposed on the conductive substrate layer 130 surrounding the conductive bump 140 and located between the stop conductive layer 170 and the conductive substrate layer 130. The third metal component is also disposed between the first metal component 150 and the conductive bump 140, and is spaced apart from the stop conductive layer 170. The material and manufacturing process of the third metal component are the same as those of the second metal component 160, and will not be described in detail here.

[0072] In this embodiment, a second pyrolytic adhesive layer 191 is provided at the end of the third metal component 190 away from the stop conductive layer 170. The third metal component 190 is bonded and fixed to the conductive substrate layer 130 by the second pyrolytic adhesive layer 191. The second pyrolytic adhesive layer 191 is configured to melt at the welding temperature, so that the third metal component 190 detaches from the conductive substrate layer 130 and a heat dissipation gap is formed between the third metal component 190 and the conductive substrate layer 130. Specifically, the material and preparation process of the second pyrolytic adhesive layer 191 are the same as those of the first pyrolytic adhesive layer 151, and will not be described in detail here.

[0073] It should be noted that the first metal component 150 and the third metal component 190 can be spaced apart, and the first pyrolytic adhesive layer 151 and the second pyrolytic adhesive layer 191 can also be spaced apart. For example, the third metal component 190 can be closer to the center of the conductive bump 140. By using the first metal component 150 and the third metal component 190, the conductive bump 140 can be divided into multiple blocks, thereby dividing the large pad of the conductive substrate layer 130 into multiple points for current conduction. At high frequencies, the current of the large copper pad is usually concentrated at the edge. Here, the pad can be divided to form multiple independent current paths, resulting in a more uniform current distribution, a smaller loop area, and lower parasitic inductance, which is beneficial for high-speed signal transmission. Furthermore, it enables multi-channel high-current power supply (Power / Ground conductive pillar array), and the divided pad allows the current to flow into different blocks of the conductive bump 140 in a dispersed manner, preventing excessively high current density at a single point.

[0074] During actual welding, both the first and second pyrolytic adhesive layers soften and melt at the welding temperature, and the adhesive force disappears. This causes the first metal part 150 and the third metal part 190 to fall into the receiving groove 161 formed by the second metal part 160 under gravity, and a heat dissipation gap is formed between the third metal part 190 and the conductive base layer 130. This heat dissipation gap can improve the heat dissipation capacity of the internal conductive bump 140 and improve the heat dissipation performance of the overall bump structure.

[0075] In this embodiment, the first metal part 150 and the third metal part can be of the same length, so that they fall into the receiving groove 161 simultaneously. Of course, in other preferred embodiments of the present invention, the length of the third metal part 190 can be greater than the length of the first metal part 150, so that after the welding falls off, the second metal part 160, the first metal part 150 and the third metal part 190 form a stepped structure.

[0076] See Figure 16 and Figure 17This invention also provides a 2.5D microbump soldering module 400, including a substrate 410, an interposer 420, and a 2.5D microbump package structure 100 as described above. The interposer 420 is soldered and fixed to the substrate 410, and the 2.5D microbump package structure 100 is flip-chip soldered to the interposer 420. Solder bumps and solder wiring structures are provided on the bottom side of the interposer 420. The solder bumps can be soldered and fixed to pads on the substrate 410, and a protective adhesive layer is formed by dispensing adhesive. Simultaneously, a transition pad is provided on the top side of the interposer 420, and the transition pad and the solder wiring structure on the bottom side are vertically interconnected via a TSV structure. The 2.5D microbump package structure 100 is correspondingly soldered to the transition pad. The solder cap layer 180 melts during soldering, and the molten solder can laterally climb to the vicinity of the conductive bump 140. Meanwhile, the first pyrolytic adhesive layer 151 and the second pyrolytic adhesive layer soften and melt at the soldering temperature, causing the adhesive force to disappear. This allows the first metal part 150 and the third metal part to fall under gravity into the receiving groove 161 formed by the second metal part 160, creating a stepped structure. Furthermore, a heat dissipation gap is formed between the third metal part and the conductive substrate layer 130, which enhances the heat dissipation capacity of the internal conductive bump 140 and improves the overall heat dissipation performance of the bump structure. Simultaneously, the conductive bump 140 is soldered to the corresponding transition pads on the interposer layer 420, and protection is achieved after soldering through an adhesive layer formed by dispensing.

[0077] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A 2.5D microbump packaging structure, characterized in that, include: The substrate has a solder pad on one side surface; A substrate wiring assembly layer is disposed on one side surface of the substrate and electrically connected to the solder pad; A conductive substrate layer is disposed on the substrate wiring assembly layer and electrically connected to the substrate wiring assembly layer; Conductive bumps are disposed on the conductive substrate layer; A first metal component is disposed on the conductive substrate layer surrounding the conductive bump; The second metal component is spaced around the conductive bump and is offset from the first metal component. A stop conductive layer is disposed on the conductive bump and covers the second metal part, wherein the first metal part and the second metal part are both located between the stop conductive layer and the conductive substrate layer. The first metal part is spaced apart from the stop conductive layer, and one end of the second metal part is connected to the stop conductive layer, and the other end protrudes toward the substrate and is spaced apart from the conductive substrate layer. A welding cap layer is disposed on the stop conductive layer.

2. The 2.5D microbump packaging structure according to claim 1, characterized in that, A first pyrolytic adhesive layer is provided at the end of the first metal part away from the stop conductive layer. The first metal part is bonded and fixed to the conductive substrate layer by the first pyrolytic adhesive layer. The first pyrolytic adhesive layer is configured to melt at the welding temperature so that the first metal part is detached from the conductive substrate layer.

3. The 2.5D microbump packaging structure according to claim 2, characterized in that, The second metal member is disposed around the conductive bump, and a receiving groove is formed between the second metal member and the sidewall of the conductive bump. The first metal member corresponds to the receiving groove and is configured to fall into the receiving groove after being removed from the conductive substrate layer.

4. The 2.5D microbump packaging structure according to claim 3, characterized in that, The first metal part extends into the receiving groove.

5. The 2.5D microbump packaging structure according to claim 3, characterized in that, The protrusion height of the second metal piece relative to the conductive substrate is less than the length of the first metal piece in the same direction, so that the first metal piece and the second metal piece form a stepped structure after falling into the receiving groove.

6. The 2.5D microbump packaging structure according to claim 1, characterized in that, One end of the first metal component away from the stop conductive layer is connected to the conductive substrate layer, and the other end protrudes toward the stop conductive layer, and the protrusion height of the first metal component is less than the protrusion height of the second metal component.

7. The 2.5D microbump packaging structure according to claim 1, characterized in that, The welding cap layer is in the shape of a rectangular block.

8. The 2.5D microbump packaging structure according to claim 1, characterized in that, The edges of the welding cap layer, the stop conductive layer, and the conductive base layer are flush.

9. The 2.5D microbump packaging structure according to claim 1, characterized in that, The substrate wiring assembly layer includes a first dielectric layer, a second dielectric layer, and a wiring layer. The first dielectric layer covers one side surface of the substrate and exposes the solder pads. The wiring layer is disposed on the first dielectric layer and is electrically connected to the solder pads. The second dielectric layer is disposed on the first dielectric layer and partially covers the wiring layer. The conductive substrate layer is disposed on the second dielectric layer and is electrically connected to the wiring layer. The conductive substrate layer is staggered from the solder pads.

10. The 2.5D microbump packaging structure according to claim 1, characterized in that, The materials of the stop conductive layer and the conductive bumps both include at least one of copper, gold, and silver.

11. The 2.5D microbump packaging structure according to claim 1, characterized in that, The 2.5D microbump packaging structure further includes a third metal component, which is disposed on the conductive substrate layer surrounding the conductive bump and located between the stop conductive layer and the conductive substrate layer. The third metal component is disposed between the first metal component and the conductive bump and is spaced apart from the stop conductive layer.

12. The 2.5D microbump packaging structure according to claim 11, characterized in that, A second pyrolytic adhesive layer is provided at one end of the third metal component away from the stop conductive layer. The third metal component is bonded and fixed to the conductive substrate by the second pyrolytic adhesive layer. The second pyrolytic adhesive layer is configured to melt at a welding temperature so that the third metal component detaches from the conductive substrate layer and a heat dissipation gap is formed between the third metal component and the conductive substrate layer.

13. A method for fabricating a 2.5D microbump encapsulation structure, used to fabricate the 2.5D microbump encapsulation structure as described in claim 1, characterized in that, The preparation method includes: A substrate is provided, wherein a solder pad is provided on one side surface of the substrate; A substrate wiring assembly layer is formed on one side surface of the substrate, wherein the substrate wiring assembly layer is electrically connected to the solder pad; A conductive substrate layer is formed on the substrate wiring assembly layer, wherein the conductive substrate layer is electrically connected to the substrate wiring assembly layer. A first metal element is formed on the conductive substrate layer; A conductive bump and a second metal member are formed on the conductive substrate layer, wherein the first metal member is located around the conductive bump, and the second metal member is spaced around the conductive bump and offset from the first metal member. A stop conductive layer is formed on the conductive bump, wherein the stop conductive layer covers the second metal part, and both the first metal part and the second metal part are located between the stop conductive layer and the conductive substrate layer. The first metal part is spaced apart from the stop conductive layer, and one end of the second metal part is connected to the stop conductive layer, while the other end protrudes toward the substrate and is spaced apart from the conductive substrate layer. A solder cap layer is formed on the stop conductive layer.

14. The method for fabricating the 2.5D microbump encapsulation structure according to claim 13, characterized in that, The step of forming a first metal element on the conductive substrate layer includes: A first photoresist layer is formed on the conductive substrate layer; A groove is formed by cutting a groove in the first photoresist layer; A first metal part is formed by electroplating in the first groove; Remove the first photoresist layer.

15. The method for fabricating the 2.5D microbump encapsulation structure according to claim 13, characterized in that, The step of forming conductive bumps and a second metal element on the conductive substrate layer includes: A second photoresist layer is formed on the conductive substrate layer; A groove is formed on the second photoresist layer to form a bump window exposing the conductive substrate layer and a second groove spaced apart from the conductive substrate layer, wherein the second groove is located around the bump window and the first metal member is located between the bump window and the second groove; Conductive bumps and second metal parts are electroplated in the bump window and the second groove, respectively, wherein the first metal part is located around the conductive bump, and the second metal part is spaced around the conductive bump and offset from the first metal part.

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