CN102142421B - Solder-free metal pillar die attach construction - Google Patents

Abstract

The invention relates to a metal column chip connection structure without solder, wherein the chip is provided with a plurality of metal columns, and each metal column is provided with a top surface and two parallel side walls. The substrate has a plurality of pads on the upper surface, each pad having a cavity bottom and two cavity sides. The chip is applied with heat, pressure and ultrasonic waves, so that the top surface of the metal column is self-welded to the bottom surface of the recess, and the parts of the two parallel side walls of the metal column are self-welded to the sides of the recess, so that a U-shaped metal bonding section without solder is formed between the metal column and the connecting pad. Therefore, the solder is not needed to be used for chip connection, and the product particularly applied to the chip connection of metal column welding can save the welding material joint cost and greatly improve the bonding strength and the electric conductivity of the welding spot.

Description

Solder-free metal pillar die attach construction

technical field

The invention relates to a semiconductor device, in particular to a solder-free metal post chip connection structure and method. the

Background technique

Press, flip-chip packaging technology (Flip-Chip) is an advanced chip packaging technology, which can shorten the transmission distance between the chip and the substrate, and has better electrical performance than wire bonding, so it is gradually popularized. In particular, IBM later developed an innovative flip-chip packaging technology, using metal pillars on the chip to replace the previous solder balls, and using solder to connect the metal pillars on the chip and the pads on the substrate. There will be no change in the shape of the previous solder balls during soldering, so the pitch of the metal pillars can be reduced more densely (bump pitch can reach less than 50 microns, such as 30 microns), to achieve higher density or omit RDL ( Reconfiguring the bump configuration of the circuit layer), this technology is called "metal post soldering chip connection", which is the so-called MPS-C2 (Metal Post Solder-Chip Connection) technology. This MPS-C2 related technology can be found in US Patent No. 6,229,220 B1 "Bump structure, bump forming method and package connecting body". the

As shown in FIG. 1 , a conventional MPS-C2 metal pillar chip connection structure 100 mainly includes a chip 110 and a substrate 120 . The chip 110 is provided with a plurality of metal pillars 112 protruding from a surface 111 of the chip 110 . An upper surface 121 of the substrate 120 has a plurality of pads 122 corresponding to the metal pillars 112 respectively. Specifically, the metal posts 112 are welded on the pads 122 by a plurality of solders 150 , and an underfill 140 is formed to cover the metal posts 112 , the pads 122 and the pads 122 . Solder 150. To achieve the electrical connection between the chip 110 and the substrate 120, the solder 150 is used as the soldering interface, which is different from the metal pillars 112 and the pads 122 in terms of material and melting point, and is prone to solder joint breakage and Risk of increased impedance. the

Therefore, the conventional MPS-C2 technology uses the solders 150 to connect the chip 110 to the substrate 120 . Among them, these solders 150 can be selected from solder balls (solder ball) or other solders that are different from the components of the bumps. Therefore, it is necessary to consider the metal diffusion and wettability between different materials when connecting chips. Nickel (Ni )/gold (Au) etc. as the surface coating of the bump increases a lot of soldering cost. In addition, in the subsequent reflow step, when the solder 150 is heated to the reflow temperature, the solder 150 will melt and become fluid, and overflow will occur when the solder 150 is squeezed or shaken. It may cause the metal pillars 112 to be soldered to wrong pads 122 , which will lead to electrical connection failure. the

It can be seen that the above-mentioned existing chip packaging technology obviously still has inconveniences and defects in structure and use, and needs to be further improved. In order to solve the above-mentioned problems, the relevant manufacturers have tried their best to find a solution, but no suitable design has been developed for a long time, and the general products do not have a suitable structure to solve the above-mentioned problems. This is obviously the relevant industry. urgent problem to be solved. Therefore, how to create a new type of solder-free metal pillar chip connection structure and method is one of the current important research and development topics, and it has also become a goal that the industry needs to improve. the

In view of the defects in the above-mentioned existing chip packaging technology, the inventor actively researches and innovates based on his rich practical experience and professional knowledge in the design and manufacture of such products for many years, and cooperates with the application of academic theories, in order to create a new type of free chip packaging technology. The metal post chip connection structure and method using solder can improve the general existing chip packaging technology and make it more practical. Through continuous research, design, and after repeated trial samples and improvements, the present invention with practical value is finally created. the

Contents of the invention

The main purpose of the present invention is to overcome the defects in the existing chip packaging technology, and provide a new type of solder-free metal pillar chip connection structure, the technical problem to be solved is to make it unnecessary to use the previous solder to make the chip Connect to improve the conductivity of solder joints, especially for MPS-C2 (metal pillar soldered chip connection) products, which can save the cost of using solder joints, which is very suitable for practical use. the

Another object of the present invention is to provide a novel solder-free metal post chip connection method, the technical problem to be solved is to establish a U-shaped metal bonding cross-section without solder between the metal post and the pad, The bonding strength of solder joints is greatly improved, making it more suitable for practical use. the

The purpose of the present invention and the solution to its technical problems are achieved by adopting the following technical solutions. According to the present invention, a solder-free metal pillar chip connection structure is proposed, which includes: a chip with a plurality of metal pillars protruding from a surface of the chip, each metal pillar has a top surface and two parallel sides wall; and a substrate having an upper surface and a plurality of pads on the upper surface, each pad having a cavity bottom and two sides of the cavity; wherein the chip is bonded to the upper surface of the substrate, the The top surfaces of the metal posts are self-welded to the bottom surfaces of the cavities, and the parts of the two parallel side walls of the metal posts are self-welded to the sides of the cavities on both sides, so that the gap between the metal posts and the pads Formed into a U-shaped metal bonding section without solder. the

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures. the

In the aforementioned solder-free metal pillar chip connection structure, the U-shaped metal bonding section is a copper-copper interface. the

In the aforementioned solder-free metal pillar chip connection structure, the surface of the chip is an active surface. the

In the foregoing solder-free metal pillar chip connection structure, the metal pillar further penetrates the chip. the

The aforementioned solder-free metal pillar chip connection structure further includes an underfill glue formed between the chip and the substrate to seal the metal pillars. the

In the aforementioned solder-free metal pillar chip connection structure, the depth of the cavity of the contact pad is not greater than one-third of the height of the metal pillars. the

The purpose of the present invention and the solution to its technical problem also adopt the following technical solutions to achieve. A solder-free metal post chip connection method proposed by the present invention includes: providing a chip with a plurality of metal posts protruding from a surface of the chip, each metal post having a top surface and two parallel sidewall; providing a substrate with an upper surface and a plurality of pads on the upper surface, each pad having a cavity bottom and two sides of the cavity; and bonding the chip on the upper surface of the substrate, using Heat, pressure and ultrasonic waves are applied to the chip so that the top surfaces of the metal posts are self-welded to the bottom surfaces of the cavities, and the parts of the two parallel side walls of the metal posts are self-welded to the sides of the cavities on both sides, so that A solderless U-shaped metal bonding section is formed between the metal pillars and the pads. the

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures. the

In the aforementioned solder-free metal pillar chip connection method, wherein the U-shaped metal bonding section is a copper-copper interface. the

In the aforementioned solder-free metal pillar chip connection method, the surface of the chip is an active surface. the

In the aforementioned solder-free metal pillar chip connection method, wherein the metal pillar further penetrates the chip. the

Compared with the prior art, the present invention has obvious advantages and beneficial effects. From the above, in order to achieve the above purpose, the present invention provides a solder-free metal pillar chip connection structure, which mainly includes a chip and a substrate. The chip is provided with a plurality of metal columns protruding from a surface of the chip, and each metal column has a top surface and two parallel side walls. The substrate has an upper surface and a plurality of pads on the upper surface, and each pad has a cavity bottom and two sides of the cavity. Wherein, the chip is bonded to the upper surface of the substrate, the top surfaces of the metal pillars are self-welded to the bottom surfaces of the cavities, and parts of the two parallel side walls of the metal pillars are self-welded to the sides of the cavities on both sides, A solder-free U-shaped metal bonding section is formed between the metal pillars and the pads. The present invention further discloses a connection method of the solder-free metal pillar chip connection structure. the

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures. the

In the aforementioned metal pillar chip connection structure, the U-shaped metal bonding cross section may be a copper-copper interface. the

In the aforementioned metal pillar chip connection structure, the surface of the chip can be an active surface. the

In the aforementioned metal pillar chip connection structure, the metal pillars can further penetrate the chip. the

In the aforementioned metal pillar chip connection structure, an underfill glue may be further included to be formed between the chip and the substrate to seal the metal pillars. the

In the aforementioned metal pillar chip connection structure, the depth of the cavity of the pads may not be greater than one-third of the height of the metal pillars. the

By virtue of the above technical solutions, the solder-free metal pillar chip connection structure and method of the present invention have at least the following advantages and beneficial effects:

It can be seen from the above technical solutions that the solder-free metal pillar chip connection structure and method of the present invention have the following advantages and effects:

1. The specific combination of metal pillars and pads can be used as one of the technical means, because each metal pillar has a top surface and two parallel side walls, and each pad has a concave bottom surface and two side concave holes side, and the top surface of the metal post is self-welded to the bottom surface of the cavity, and the parts of the two parallel side walls of the metal post are self-welded to the sides of the cavity on both sides, so that a U-shaped metal post without solder is formed between the metal post and the pad. Bonding section. Therefore, there is no need to use traditional solder for chip connection to improve the conductivity of solder joints, especially when applied to MPS-C2 (metal pillar soldered chip connection) products, it can save the cost of using solder joints. the

2. The specific combination relationship between the metal pillar and the pad can be used as one of the technical means, because each metal pillar has a top surface and two parallel side walls, and each pad has a concave bottom surface and two side concave holes On the other hand, heat, pressure and ultrasonic waves are applied to the chip to establish a solderless U-shaped metal bonding cross section between the metal post and the pad. Therefore, the bonding strength of the solder joint can be greatly improved. the

To sum up, the present invention relates to a solder-free metal pillar chip connection structure and method. The chip is provided with a plurality of metal pillars, and each metal pillar has a top surface and two parallel sidewalls. The substrate has a plurality of pads on the upper surface, and each pad has a bottom surface of a cavity and two sides of the cavity. Using heat, pressure and ultrasonic waves to apply to the chip, the top surface of the metal post is self-welded to the bottom of the cavity, and the two parallel side walls of the metal post are partially self-welded to the side of the two side cavities, so that the metal post and the pad Formed into a U-shaped metal bonding section without solder. Therefore, there is no need to use solder for chip connection, especially for "chip connection with metal pillar welding" products, which can save the cost of solder joints and greatly improve the bonding strength and conductivity of solder joints. The present invention has significant progress in technology, and has obvious positive effects, and is a novel, progressive and practical new design. the

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the following preferred embodiments are specifically cited below, and are described in detail as follows in conjunction with the accompanying drawings. the

Description of drawings

FIG. 1 is a schematic cross-sectional view of a conventional metal pillar chip connection structure. the

2 is a schematic cross-sectional view of a solder-free metal pillar chip connection structure according to the first embodiment of the present invention. the

3A to 3C are schematic cross-sectional views of components during the flip-chip bonding process of the metal pillar chip connection structure according to the first specific embodiment of the present invention. the

4A to 4C are schematic diagrams of the metal pillar chip connection structure of the first embodiment of the present invention depicting the metal pillars, pads and bonding in the flip-chip bonding process. the

5A to FIG. 5C are schematic diagrams illustrating the metal pillars, pads and bonding in the flip-chip bonding process of a metal pillar chip connection structure according to a variant embodiment of the present invention. the

6 is a schematic cross-sectional view of another solder-free metal pillar chip connection structure according to the second embodiment of the present invention. the

100: Metal pillar chip connection structure

110: chip

111: Surface 112: Metal Pillar

120: Substrate

121: Upper surface 122: Pad

140: Underfill 150: Solder

200: Solder-free metal pillar chip connection structure

210: chip

211: Surface 212: Metal Pillar

213: top surface 213a: top surface

214: Parallel side walls 214a: Parallel side walls

220: Substrate

221: Upper surface 222: Pad

223: Bottom of the pocket 223a: Bottom of the pocket

224: Pocket side 224a: Pocket side

230: U-shaped metal bonding section

240: bottom filler

300: Solder-free metal pillar chip connection structure

315: Through hole 316: Plating layer

Detailed ways

In order to further explain the technical means and effects of the present invention to achieve the intended purpose of the invention, the specific implementation of the solder-free metal post chip connection structure and method proposed by the present invention will be described below in conjunction with the accompanying drawings and preferred embodiments. , structure, feature and effect thereof, detailed description is as follows. the

The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of preferred embodiments with reference to the drawings. For convenience of description, in the following embodiments, the same elements are denoted by the same numbers. the

Embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, but it should be noted that these drawings are simplified schematic diagrams, and are only used to illustrate the basic structure or implementation method of the present invention, so only show Components and combinations related to this case, the components shown in the figure are not drawn in proportion to the actual number, shape, and size. Some dimensional ratios and other related dimensional ratios have been exaggerated or simplified to provide a better Clear description. The number, shape and size ratio of the actual implementation is an optional design, and the detailed component layout may be more complicated. the

According to the first embodiment of the present invention, a solder-free metal pillar chip connection structure is illustrated in the cross-sectional schematic diagram of FIG. 2 and the cross-sectional schematic diagrams of components in the flip-chip bonding process in FIGS. 3A to 3C . The solder-free metal pillar chip connection structure 200 mainly includes a chip 210 and a substrate 220 . the

Please refer to FIG. 2 , the chip 210 has a plurality of metal pillars 212 protruding from a surface 211 of the chip 210 , and each metal pillar 212 has a top surface 213 and two parallel sidewalls 214 . Specifically, the chip 210 has been formed with integrated circuit (IC) components, such as memory, logic components and application specific integrated circuits (ASIC), which can be divided into particles by a wafer. In this embodiment, the surface 211 of the chip 210 may be an active surface, that is, a surface on which an integrated circuit is formed. In detail, a plurality of welding pads (not shown in the figure) can be formed on the surface 211 (ie, the active surface) for the setting of the metal pillars 212, and protrusions can also be arranged between the welding pads and the metal pillars. An underlying metal layer (not shown in the figure) is used to avoid metal diffusion of components in the metal pillars. The material of the metal pillars 212 may include gold, copper, aluminum or alloys thereof, and electroplating may be used to form the pillars. Preferably, the top surface 213 can be flat and have the same height by grinding or surface flattening technology. the

The substrate 220 has an upper surface 221 and a plurality of pads 222 on the upper surface 221 , and each pad 222 has a cavity bottom 223 and two cavity sides 224 . In detail, the substrate 220 can be a printed circuit board (PCB), used as a medium for carrying and electrically connecting chips in the semiconductor packaging structure. In a preferred embodiment, the distance between the two cavity sides 224 of each pad 222 may not be greater than the distance between the corresponding two parallel sidewalls 214 of each metal pillar 212, so as to ensure that these parallel sides are The walls 214 are able to frictionally contact the pocket sides 224 . The material of the pads 222 may include copper, and the bottom surface 223 of the cavity and the sides 224 of the cavity on both sides may be formed by patterned etching or patterned electroplating techniques. In a preferred embodiment, the depth of the cavity of the pads 222 may not be greater than one-third of the height of the metal pillars 212, so as to prevent the metal pillars 212 from being over-embedded in the pads 222 and A non-friction contact gap between the chip 210 and the substrate 220 is maintained. In addition, in this embodiment, the metal posts 212 and the pads 222 can have the same material, for example, the metal posts 212 can be copper posts (Cu post), and the pads 222 can also be Copper groove (Cu cave). the

In addition, the chip 210 is bonded to the upper surface 221 of the substrate 220, the top surfaces 213 of the metal pillars 212 are self-welded to the bottom surfaces 223 of the cavities, and the parts of the two parallel sidewalls 214 of the metal pillars 212 are self-welded to The cavity sides 224 on both sides form a solderless U-shaped metal bonding section 230 between the metal pillars 212 and the pads 222 . In other words, the U-shaped metal bonding cross-section 230 includes at least three joint interfaces and is non-planar. The above-mentioned "joint interface" is located between the top surface 213 and the cavity bottom surface 223 and the two parallel side walls 214 and the corresponding two between pocket sides 224 . And "self-soldering" refers to utilizing the activation and diffusion of metal atoms on the surface of the metal pillars 212 to form a mutual metal bond with the pads 222 without resorting to additional solder, bump coating or other bonding agent, basically A discontinuous metal lattice interface will be generated on the U-shaped metal bonding section 230, so the impedance between the metal pillars 212 and the pads 222 will not increase after self-soldering, so as to "no solder The U-shaped metal bonding section" can be used as a solder joint to achieve better conductivity. In this embodiment, the U-shaped metal bonding section 230 can be a copper-copper interface or a gold-gold interface, and the cost of the copper-copper interface is lower. Therefore, the U-shaped metal bonding cross-section 230 will not have other impurities, fragile casting structures or intermetallic compounds, and can form a relatively flat and seamless joint surface, without using conventional solder for chip connection to improve Conductivity of solder joints. the

In addition, the solder-free metal pillar chip connection structure 200 may further include an underfill material 240 formed between the chip 210 and the substrate 220 to seal the metal pillars 212 . Due to the high fluidity of the underfill 240 before curing, a gap is avoided between the chip 210 and the substrate 220 . In a preferred embodiment, the underfill 240 can be made of a material with higher hardness, which can not only protect the metal pillars 212 but also reinforce the overall structural strength. the

Therefore, the present invention uses the specific combination relationship between metal pillars and pads as one of the technical means, without the need for solder to do chip connection in the past, especially for MPS-C2 (metal pillar soldered chip connection) products, which can save the cost of using solder joints . This is because each metal pillar 212 has a top surface 213 and two parallel sidewalls 214, and each pad 222 has a cavity bottom surface 223 and two sides cavity sides 224, and the top surfaces 213 of the metal columns 212 Self-welding to the bottom surface 223 of the cavity, and parts of the two parallel side walls 214 of the metal pillars 212 are self-welded to the corresponding sides of the cavity 224, so that between the metal pillars 212 and the pads 222 A solderless U-shaped metal bonding section 230 is formed. In addition, the bonding strength and conductivity of solder joints are greatly improved, eliminating the risk of solder joint breakage and increased impedance when traditional solder joints are used. the

The present invention also discloses a feasible but non-limiting manufacturing method of the solder-free metal pillar chip connection structure 200, illustrated in FIGS. function, and its detailed step-by-step instructions are as follows. the

Firstly, as shown in FIG. 3A , the chip 210 is provided, and a plurality of metal pillars 212 protrude from a surface 211 of the chip 210 . Each metal pillar 212 has a top surface 213 and two parallel sidewalls 214 . The top surfaces 213 do not need to be adhered to the conventionally used solder. In addition to not worrying about solder contamination, it can save a lot of solder installation costs. the

Referring to FIG. 3B , the substrate 220 is provided, and a plurality of pads 222 are disposed on the upper surface 221 of the substrate 220 , and each pad 222 has a cavity bottom 223 and two cavity sides 224 . Specifically, the bottom surface 223 of each cavity and the corresponding two sides 224 of the cavity can form a structure like a U-shaped groove. the

Referring to FIG. 3C , a flip-chip bonding step is performed to bond the chip 210 on the upper surface 221 of the substrate 220. Heat, pressure and ultrasonic waves are transmitted to the chip 210 through an adsorption thermocompression fixture (not shown in the figure), so that the top surfaces 213 of the metal posts 212 are self-welded to the bottom surfaces 223 of the cavities Parts of the two parallel side walls 214 of the metal posts 212 are self-welded to the recess sides 224 on both sides, so that a U-shaped metal bond without solder is formed between the metal posts 212 and the pads 222 Combined section 230. Among them, the so-called "ultrasonic wave" refers to the vibration frequency not less than 20,000 hertz (Hz), which produces high-frequency lateral vibrations of 20,000 to 40,000 times per second to the chip 210 and its metal pillars 212, making these metal pillars The bonding surfaces of 212 and the pads 222 are fused due to high-frequency vibration, which induces atomic diffusion to form atomic bonding of mutual metals. Therefore, no flux, current flow and heating to the melting point of the metal pillars 212 are required. By properly heating the chip 210 but not reaching the melting point of the metal pillars 212 so that the metal pillars 212 connected to the chip 210 are heated and expanded at the same time, the distance between the two parallel side walls 214 of the same metal pillar 212 can be slightly greater than the corresponding The distance between the two parallel sidewalls 214 of the pads 222 is used to increase the frictional contact between the two parallel sidewalls 214 of the metal pillars 212 and the recess sides 224 on both sides, so as to achieve vertical self-welding of the sides. Applying pressure to the chip 210 ensures frictional contact between the top surfaces 213 of the metal pillars 212 and the bottom surfaces 223 of the cavities, so as to achieve central horizontal self-welding. Therefore, by applying heat, pressure and ultrasonic waves to the chip 210, a solderless U-shaped metal bonding section 230 can be established between the metal pillars 212 and the pads 222, which can greatly improve the bonding strength of the solder joints. . the

4A to FIG. 4C are schematic diagrams of the metal pillar chip connection structure 200 showing its metal pillars, pads and bonding in the flip-chip bonding process. As shown in FIG. 4A, the top surface 213 of each metal column 212 can be rectangular, and each metal column 212 can have a pair of parallel wall surfaces in addition to the above-mentioned two parallel side walls 214, so that the The metal pillars 212 are formed in a rectangular parallelepiped. In addition, as shown in FIG. 4B and FIG. 4C , the area of the bottom surface 223 of each pad 222 may not be larger than the area of the corresponding top surface 213 . More specifically, when the metal pillars 212 are bonded to the pads 222, heat, pressure and ultrasonic waves are applied to the chip 210, the top surfaces 213 and the corresponding cavity bottom surfaces 223 and the parallel side walls 214 and the corresponding cavity side 224 vibrate and rub rapidly, so that the top surface 213 of the metal columns 212 is self-welded to the bottom surface 223 of the cavity, and the two parallel side walls 214 of the metal columns 212 are partially Self-welding to the two side pocket sides 224 . The direction indicated by the arrow in FIG. 4C is the vibration direction of the ultrasonic wave, which is parallel to the parallel side walls 214 and the cavity sides 224 . the

5A to FIG. 5C are schematic diagrams of the metal pillar chip connection structure 200 in a variant embodiment showing its metal pillars, pads and bonding during the flip-chip bonding process, to illustrate that the top surface and contacts of the metal pillars are not limited. The shape of the pad's pocket floor. As shown in FIG. 5A , the top surface 213a of each metal post 212 can be square, and can have two pairs of parallel side walls 214a that are parallel and equal to each other. Moreover, as shown in FIG. 5B , each pad 222 is recessed to form a shape like a receiving groove. In addition to having two sides of the cavity side 224 a, another pair of parallel side walls is formed. Furthermore, the shape of the bottom surface 223a of the cavity of the pads 222 can be rectangular, and the area of the bottom surface 223a of the cavity of the pads 222 can be larger than the area of the top surface 213a of the metal pillars 212, in order to benefit oneself Weld the top surfaces 213a of the metal pillars 212 to the bottom surfaces 223a of the cavities. In addition, the shorter sides of the bottom surfaces 223a of the cavities (that is, the distance between the two cavities sides 224a of the pads 222) are not longer than the lengths of the corresponding sides of the top surfaces 213a of the corresponding metal pillars 212 (that is, the two parallel side walls of the metal pillars 212). 214a), so when the chip 210 is bonded to the substrate 220, the two parallel side walls 214a of the metal pillars 212 can vibrate to the corresponding The two cavity sides 224a of the pad 222 are used for self-welding the two parallel sidewalls 214a of the metal pillars 212 to the two cavity sides 224a. the

According to the second embodiment of the present invention, another solder-free metal pillar chip connection structure 300 is illustrated in the schematic cross-sectional view of FIG. 6 . The main components that are the same as those in the first embodiment will be marked with the same symbols and will not be described in detail. the

Please refer to FIG. 6 , the solder-free metal pillar chip connection structure 300 mainly includes a chip 210 and a substrate 220 . The chip 210 has a plurality of metal pillars 212 protruding from a surface 211 of the chip 210 , and each metal pillar 212 has a top surface 213 and two parallel sidewalls 214 . The substrate 220 has an upper surface 221 and a plurality of pads 222 on the upper surface 221 , and each pad 222 has a cavity bottom 223 and two cavity sides 224 . Wherein, the chip 210 is bonded to the upper surface 221 of the substrate 220, the top surfaces 213 of the metal columns 212 are self-welded to the bottom surfaces 223 of the cavities, and the parts of the two parallel side walls 214 of the metal columns 212 are self-welded to The cavity sides 224 on both sides form a solderless U-shaped metal bonding section 230 between the metal pillars 212 and the pads 222 . Preferably, the metal pillars 212 can further penetrate the chip 210 . Furthermore, a plurality of through holes 315 may be formed where the chip 210 is penetrated by the metal pillars 212 , and a wall of each through hole 315 is provided with an electroplating layer 316 . The electroplating layers 316 can be made of conductive materials, such as copper (Cu). Specifically, the through holes 315 are also so-called through silicon vias (Though Silicon Via, TSV). The structure through which the metal pillars 212 penetrate the chip 210 can provide vertical electrical conduction and stabilize the metal pillars 212, which is helpful for the ultrasonic vibration conduction from the chip 210 to the metal pillars 212, so as to promote The U-shaped metal bonding section 230 is formed. In this embodiment, the protruding surfaces 211 of the metal pillars 212 can be the back side of the chip 210 , so the active surface of the chip 210 is far away from the substrate 220 to achieve a better heat dissipation effect. In addition, the exposed end surfaces of the metal pillars 212 can be stacked three-dimensionally with another chip. the

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes, but all the content that does not depart from the technical solution of the present invention, according to the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments by the technical essence still belong to the scope of the technical solutions of the present invention. the

Claims (4)

1. A solder-free metal post chip connection structure, characterized in that it comprises: A chip is provided with a plurality of metal pillars protruding from a surface of the chip, each metal pillar has a top surface and two parallel side walls; A substrate having an upper surface and a plurality of pads disposed on the upper surface, each pad having a cavity bottom and two sides of the cavity; and an underfill glue is formed between the chip and the substrate to seal the metal pillars; Wherein, the chip is bonded to the upper surface of the substrate, the top surfaces of the metal pillars are self-welded to the bottom surfaces of the cavities, and parts of the two parallel side walls of the metal pillars are self-welded to the sides of the cavities on both sides, A solder-free U-shaped metal bonding section is formed between the metal posts and the pads, and the depth of the recesses of the pads is not greater than one-third of the height of the metal posts. 2 . The solder-free metal pillar chip connection structure according to claim 1 , wherein the U-shaped metal bonding section is a copper-copper interface. 3 . 3 . The solder-free metal pillar chip connection structure according to claim 1 , wherein the surface of the chip is an active surface. 4 . 4. The solder-free metal pillar chip connection structure according to claim 1, wherein the metal pillar further penetrates the chip.

Images