阅读说明：本技术 一种封装结构及封装方法 (Packaging structure and packaging method ) 是由 卢玉溪 曾昭孔 陈武伟 黄柏荣 于 2020-12-17 设计创作，主要内容包括：本申请公开了一种封装结构及封装方法,其中封装结构,包括基板及设置在所述基板上的芯片和散热盖,所述芯片与所述散热板之间设置有金属导热层,所述金属导热层与所述散热盖之间和/或所述金属导热层与所述芯片之间设置有若干排气通道,所述排气通道的一端与所述金属导热层的四周边缘相通。本申请实施例提供的封装结构在,所述金属导热层与所述散热盖之间和/或所述金属导热层与所述芯片之间设置有若干排气通道,将金属导热层分割为面积小的区域,防止助焊剂挥发的气体在中心区域聚集,由于铟片的张力而包裹排不出去。由于熔化的铟片与分割线处的浸润性差,助焊剂挥发的气体可以沿着分割线逸出,起到排气槽的作用。(The application discloses packaging structure and packaging method, wherein packaging structure, including the base plate and set up chip and heat dissipation lid on the base plate, the chip with be provided with the metal heat-conducting layer between the heating panel, the metal heat-conducting layer with between the heat dissipation lid and/or the metal heat-conducting layer with be provided with a plurality of exhaust passage between the chip, exhaust passage's one end with the edge all around of metal heat-conducting layer communicates with each other. The packaging structure that this application embodiment provided is, the metal heat-conducting layer with between the heat dissipation lid and/or the metal heat-conducting layer with be provided with a plurality of exhaust passage between the chip, cut apart the area for the little region of area with the metal heat-conducting layer, prevent the volatile gas of scaling powder at the regional gathering in center, because the tension of indium piece and parcel are not discharged. Because the wettability of the melted indium sheet and the division line is poor, the gas volatilized by the soldering flux can escape along the division line, and the function of an exhaust groove is realized.)

1. The utility model provides a packaging structure, includes the base plate and sets up chip and heat dissipation lid on the base plate, its characterized in that, the chip with be provided with the metal heat-conducting layer between the heating panel, the metal heat-conducting layer with between the heat dissipation lid and/or the metal heat-conducting layer with be provided with a plurality of exhaust passage between the chip, exhaust passage's one end with the edge all around of metal heat-conducting layer communicates with each other.

2. The package structure according to claim 1, wherein a back-plated metal layer is disposed between the metal heat conducting layer and the heat dissipation cover and/or between the metal heat conducting layer and the chip, and the back-plated metal layer is made of an element that is easily wettable with the metal heat conducting layer.

3. The package structure of claim 2, wherein the vent channel is disposed on the back-plated metal layer and on a surface of the back-plated metal layer in contact with the metal thermal conductive layer.

4. The package structure according to claim 3, wherein the exhaust channel divides the gold-plated area on the heat dissipation cover and/or the chip, on which the back-plated metal layer is disposed, into a plurality of sub-areas, the exhaust channel is not disposed with the back-plated metal layer, and the sub-areas are disposed with the back-plated metal layer.

5. The package structure of claim 4, wherein the shape of the vent channel comprises: one or more of a single line type, a cross type, an X type, a grid type, and a radial type.

6. The package structure according to any one of claims 3 to 5, wherein a back-plated non-gold layer having poor wettability with the metal heat conductive layer is disposed on the air vent channel.

7. A method of packaging, comprising:

providing a substrate, wherein a part of the surface of the substrate is provided with a chip;

forming an exhaust channel on the top surface of the chip in one or more ways of slotting, blanking, attaching foreign matters and reducing roughness, and forming an electroplating metal layer by an electroplating process;

forming a metal heat conduction layer on the top surface of the electroplated metal layer;

providing a heat dissipation cover, wherein the heat dissipation cover is covered above the chip, an electroplating metal layer is arranged at the contact position of the heat dissipation cover and the metal heat dissipation layer, and the electroplating metal layer is provided with an exhaust channel formed by one or more modes of slotting, blank, attaching foreign matters and reducing roughness;

fixing the radiating cover on the substrate in a through mounting manner;

performing high-temperature reflow soldering, wherein the temperature adopted by the high-temperature reflow soldering is higher than the melting point of the metal heat conduction layer;

and welding the heat dissipation cover, the chip and the metal heat conduction layer together through a high-temperature reflow soldering process.

8. The method of claim 7, wherein the vent passage is formed in a manner comprising: one or more of grooving, blank, attaching foreign matters and reducing roughness.

9. The packaging method of claim 7, wherein said vent passage divides said gold-plated area into said plurality of sub-areas by a slotted pattern, the method comprising: and processing the heat dissipation cover or the chip in one or more of laser grooving, dry etching, physical cutting or mold forming.

10. The packaging method of claim 7, wherein said vent passages divide said gold plated region into said plurality of sub-regions by a blank pattern, the method comprising: a mask plate is arranged on the heat dissipation cover or the chip, the sub-area is plated with gold through an electroplating process, and the exhaust channel is not plated with gold.

11. The packaging method of claim 7, wherein the exhaust channel divides the gold-plated area into sub-areas by attaching foreign matter, the method comprising: the exhaust channel is formed on the heat dissipation cover or the chip in one or more modes of glue spraying, glue dispensing and adhesive tape pasting.

12. The packaging method of claim 7, wherein said vent passages divide said gold-plated region into said plurality of sub-regions by a roughness-reducing form, the method comprising: and forming the exhaust channel on the heat dissipation cover or the chip in one or more modes of polishing, waxing and film coating.

Technical Field

The present application relates generally to the field of semiconductor manufacturing technology, and more particularly, to a package structure and a package method.

Background

Moore's law has been driving the development of the integrated circuit industry for many years, and the number of transistors that can be accommodated on a chip doubles every 18-24 months, and performance doubles. Mainly thanks to the continuous development of the process, 14nm → 10nm → 7nm → 5 nm. However, Moore's law is in the bottleneck at present, and the performance of the chip is more and more required by the application end, so that the sizes of the chip and the substrate are inevitably increased at present. At present, the substrate size of 100mmx100mm is required in the industry, and the traditional heat-conducting silicone grease material cannot meet the requirement of the product with the heat-radiating cover, which is large in size and provided with the embedded balls, and generally needs to use indium sheets as heat-conducting materials.

In the semiconductor industry, thermal interface materials are mainly used for filling up micro-voids and cavities with uneven surfaces generated during heterogeneous interface contact or combination in a high-density system-in-package structure, reducing heat transfer resistance and improving heat dissipation of devices. The gaps are filled with a thermal interface material with high thermal conductivity, air in the gaps is removed, an effective heat conduction channel is established between the electronic element and the radiator, the contact thermal resistance can be greatly reduced, and the function of the radiator is fully exerted. In semiconductor packaging, an important quality requirement is to ensure 100% coverage of the solder between the chip and the heat sink cap, which is typically greater than 90% as required by regulatory standards in the industry.

And large-size chips use indium sheets as heat conduction materials, and the use of an indium heat sink for reflow soldering generally requires the use of a flux. At present, the indium sheet is generally welded by reducing the soldering flux, gas is generated when the soldering flux reduces the surface to be welded and the oxide film on the surface of the solder during welding, and the gas can be pumped out by adopting vacuum reflow welding in a small-sized chip. However, in the case of a large-sized chip, the gas generated during welding is sealed in the welding surface and cannot escape conveniently or even escape because no escape channel exists, thereby bringing about a lot of troubles for reducing the welding void ratio and improving the welding quality.

As shown in fig. 1, the temperature of reflow soldering (240 ℃) due to the ball mounting is higher than the melting point (156 ℃) of the indium plate as shown in the ultrasonic scanning diagram of the soldering area of the chip surface in the prior art. Therefore, the gas volatilized by the soldering flux can extrude the liquid indium to flow around the chip, and a large number of cavities are generated between the chip and the radiating cover, so that the radiating performance is reduced.

Disclosure of Invention

In view of the above-mentioned defects or shortcomings in the prior art, it is desirable to provide a package structure and a package method, which can effectively solve the problem of reduced heat dissipation due to a large number of holes generated between a large-sized chip and a heat dissipation cover.

On the one hand, this application provides a packaging structure, be in including base plate and setting chip and heat dissipation lid on the base plate, the chip with be provided with the metal heat-conducting layer between the heating panel, the metal heat-conducting layer with between the heat dissipation lid and/or the metal heat-conducting layer with be provided with a plurality of exhaust passage between the chip, exhaust passage's one end with the edge all around of metal heat-conducting layer communicates with each other.

Furthermore, a back-plated metal layer is arranged between the metal heat conduction layer and the heat dissipation cover and/or between the metal heat conduction layer and the chip, and the back-plated metal layer is made of elements which are easy to infiltrate into the metal heat conduction layer.

Further, the exhaust channel is arranged on the back metal coating layer and on the surface of the back metal coating layer, which is in contact with the metal heat conduction layer.

Furthermore, the exhaust channel divides the heat dissipation cover and/or the gold-plated area provided with the back metal plating layer on the chip into a plurality of sub-areas, the exhaust channel is not provided with the back metal plating layer, and the sub-areas are internally provided with the back metal plating layer.

Further, the shape of the exhaust passage includes: one or more of a single line type, a cross type, an X type, a grid type, and a radial type.

Further, the exhaust passage is formed in a manner including: one or more of grooving, blank, attaching foreign matters and reducing roughness.

Preferably, a back-plated non-gold layer with poor wettability with the metal heat conduction layer is arranged on the exhaust channel.

In another aspect, the present application further provides a packaging method, including:

providing a substrate, wherein a part of the surface of the substrate is provided with a chip;

forming an exhaust channel on the top surface of the chip in one or more ways of slotting, blanking, attaching foreign matters and reducing roughness, and forming an electroplating metal layer by an electroplating process;

forming a metal heat conduction layer on the top surface of the electroplated metal layer;

providing a heat dissipation cover, wherein the heat dissipation cover is covered above the chip, an electroplating metal layer is arranged at the contact position of the heat dissipation cover and the metal heat dissipation layer, and the electroplating metal layer is provided with an exhaust channel formed by one or more modes of slotting, blank, attaching foreign matters and reducing roughness;

fixing the radiating cover on the substrate in a through mounting manner;

performing high-temperature reflow soldering, wherein the temperature adopted by the high-temperature reflow soldering is higher than the melting point of the metal heat conduction layer;

and welding the heat dissipation cover, the chip and the metal heat conduction layer together through a high-temperature reflow soldering process.

Preferably, the exhaust passage divides the gold plating region into the plurality of sub-regions by a grooved pattern, the method comprising: and processing the heat dissipation cover or the chip in one or more of laser grooving, dry etching, physical cutting or mold forming.

Preferably, the exhaust passage divides the gold plating region into the plurality of sub-regions by a blank form, the method comprising: a mask plate is arranged on the heat dissipation cover or the chip, the sub-area is plated with gold through an electroplating process, and the exhaust channel is not plated with gold.

Preferably, the exhaust passage divides the gold plating region into the plurality of sub-regions by attaching a foreign substance, the method comprising: the exhaust channel is formed on the heat dissipation cover or the chip in one or more modes of glue spraying, glue dispensing and adhesive tape pasting.

Preferably, the exhaust passage divides the gold plating region into the plurality of sub-regions by a roughness reducing form, the method comprising: and forming the exhaust channel on the heat dissipation cover or the chip in one or more modes of polishing, waxing and film coating.

The technical scheme provided by the embodiment of the application can have the following beneficial effects:

the packaging structure that this application embodiment provided is, the metal heat-conducting layer with between the heat dissipation lid and/or the metal heat-conducting layer with be provided with a plurality of exhaust passage between the chip, cut apart the area for the little region of area with the metal heat-conducting layer, prevent the volatile gas of scaling powder at the regional gathering in center, because the tension of indium piece and parcel are not discharged. Because the wettability of the melted indium sheet and the division line is poor, the gas volatilized by the soldering flux can escape along the division line, and the function of an exhaust groove is realized.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:

FIG. 1 is a prior art ultrasonic scan of a bonding area on a chip surface;

fig. 2 is a schematic structural diagram of a package structure according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a structure for providing gold-plated regions according to an embodiment of the present application;

FIG. 4 is a diagram of an ultrasonic scan of a gold-plated area on a surface of a chip according to an embodiment;

FIG. 5 is a diagram of an ultrasonic scan of a gold-plated area on the surface of a chip according to a second embodiment;

FIG. 6 is a scanned ultrasonic image of the gold-plated areas on the chip surface in the third example.

1. A substrate; 2. a chip; 3. a heat dissipation cover; 4. a metal heat conducting layer; 5. an exhaust passage; 6. salient points; 7. a solder ball; 8. bottom sealing glue; 9. a binder; 10. back plating a metal layer; 11. a gold-plated region; 12. a sub-region.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

Please refer to fig. 2 in detail, the present application provides a package structure, which includes a substrate 1, and a chip 2 and a heat dissipation cover 3 disposed on the substrate 1, wherein a metal heat conduction layer 4 is disposed between the chip 2 and the heat dissipation plate, a plurality of exhaust channels 5 are disposed between the metal heat conduction layer 4 and the heat dissipation cover 3 and/or between the metal heat conduction layer 4 and the chip 2, and one end of each exhaust channel 5 is communicated with the peripheral edge of the metal heat conduction layer 4.

The exhaust passage 5 is used for discharging air flow or gas generated during welding, so that when the exhaust passage 5 is arranged, one end of the exhaust passage is communicated with the outside of the metal heat conduction layer 4, the gas or the air flow can be conveniently discharged out of the metal heat conduction layer 4, and the phenomenon that a large cavity is gathered at the center of the chip 2 is avoided.

The surface of the chip 2 is provided with a barrier layer, and the inner surface of the heat dissipation cover 3 is subjected to nickel plating treatment. Wherein the metal heat conduction layer 4 is selected from one or more of indium and indium alloy. In addition, the heat dissipation cover 3 is fixed to the substrate 1 by an adhesive 9.

It should be noted that, the surface of the heat dissipation cover 3 is generally plated with nickel, which has the functions of oxidation resistance, corrosion resistance, and enhanced hardness and wear resistance. Indium and nickel have poor solderability and require gold layers for soldering. Similarly, the chip 2 is a silicon substrate, and the indium plate is soldered to the silicon, so that the indium can diffuse into the silicon to affect the semiconductor properties and even damage the chip 2, and therefore, a barrier layer, which is generally a material such as vanadium nickel or titanium, needs to be added on the surface of the chip 2.

In addition, during the setting, a back-plated metal layer 10 is arranged between the metal heat conduction layer 4 and the heat dissipation cover 3 and/or between the metal heat conduction layer 4 and the chip 2, and the back-plated metal layer 10 is made of an element which is easy to infiltrate into the metal heat conduction layer 4. Preferably, the material of the back metal plating layer 10 is gold.

The wettability of the solder is the diffusion capability of the solder when the solder is molten, the wettability of the indium sheet and the nickel is poor, the wettability of the indium sheet, the chip 2 and the heat dissipation cover 3 is improved by adding the gold layer between the metal heat conduction layer 4 and the heat dissipation cover 3 or the core plate, and during welding, the indium generates a sufficient diffusion layer on the boundary of the indium and the gold, so that the bonding strength is increased. Meanwhile, the gold plate is arranged between the metal heat conduction layer 4 and the heat dissipation cover 3 or the chip 2, and can absorb distortion caused by a difference of thermal expansion coefficients between the metal heat conduction layer 4 and the chip 2 or the heat dissipation cover 3, thereby inhibiting fracture in the welding material and reducing internal stress.

By arranging the gold layer which is easy to be soaked in the metal heat conduction layer 4, the fracture of a welding part or the separation of a local chip 2 can be reduced, so that the reliability of the electronic element is improved.

The back metal plating layer 10 is formed on the heat dissipation cover 3 and/or the chip 2 by a chemical process or an electroplating process through the back metal plating layer 10. The exhaust channel 5 is disposed on the back metal layer 10 and on the surface of the back metal layer 10 in contact with the metal heat conduction layer 4.

In a specific setting, the exhaust channel 5 divides the gold plating area 11, on which the back plating metal layer 10 is disposed, on the heat dissipation cover 3 and/or the chip 2 into a plurality of sub-areas 12, the back plating metal layer 10 is not disposed on the exhaust channel 5, and the back plating metal layer 10 is disposed in the sub-areas 12. As shown in fig. 3, the shape of the exhaust passage 5 includes: single line type (shown as a in figure 3), cross type (shown as b in figure 3), X type (shown as c in figure 3), grid type (shown as d and e in figure 3), and radiation type (shown as f in figure 3). Wherein the exhaust passage 5 is formed in a manner including: one or more of grooving, blank, attaching foreign matters and reducing roughness.

When the exhaust passage 5 is specifically provided, the area ratio should be considered, and the width of a single passage is generally less than 1 mm. If the area of the 20 × 20mm chip 2 is cross-shaped, the area ratio of the exhaust channel 5 in the gold-plated area 11 is approximately equal to 10%, and the area ratio of the exhaust channel 5 is too large, which may reduce the contact area between the metal heat conduction layer 4 on the chip 2 and the chip 2, and thus reduce the heat dissipation efficiency of the chip 2. By arranging the exhaust passages 5 with different shapes, the area occupation ratios of the different exhaust passages 5 are controlled.

It should be noted that, in the specific arrangement, the heat dissipation cover 3 and the air exhaust channel 5 on the chip 2 may be arranged in different manners, and likewise, the shape of the air exhaust channel 5 may also be the same or different, and is not limited in the embodiments disclosed in the present application.

In some embodiments, the exhaust channel 5 divides the gold-plated region 11 into the sub-regions 12 by a slotted form, the method comprising: and processing the heat dissipation cover 3 or the chip 2 in one or more of laser grooving, dry etching, physical cutting and mold forming.

In some embodiments, the exhaust channel 5 divides the gold-plated region 11 into the sub-regions 12 by a blank form, the method comprising: the heat dissipation cover 3 or the chip 2 is provided with a mask plate, the sub-area 12 is plated with gold through an electroplating process, and the exhaust passage 5 is not plated with gold.

The back metal layer 10 is formed on the chip 2 or the heat dissipation cover 3 by heating the evaporation material to evaporate in a vacuum environment, and depositing the evaporation material on the target substrate 1 to form a corresponding film layer. The evaporation method is simple to operate, the film thickness is easy to control, doping is easy to realize, and the sub-region 12 is quickly formed through a mask plate with the same shape as the gold-plated region 11 to be formed.

In some embodiments, the exhaust channel 5 divides the gold-plated region 11 into the plurality of sub-regions 12 by attaching a foreign material, and the method includes: the exhaust channel 5 is formed on the heat dissipation cover 3 or the chip 2 by one or more of glue spraying, glue dispensing and adhesive tape adhering.

In some embodiments, the exhaust channel 5 divides the gold-plated region 11 into the sub-regions 12 by reducing roughness, the method comprising: the exhaust passage 5 is formed on the heat dissipation cover 3 or the chip 2 by one or more of polishing, waxing and plating.

In some embodiments, the exhaust channel 5 opened by any of the above methods is provided with a back-plated non-gold layer having poor wettability with the metal heat conduction layer 4, for example, by plating nickel on the exhaust channel 5, and due to poor wettability of the molten indium sheet and nickel at the parting line, the gas volatilized from the flux can escape along the parting line, and functions as an exhaust groove.

It should be noted that the exhaust passage 5 is provided to avoid the hot spot position of the chip 2 as much as possible. From the integration aspect, moore's law indicates that the number of semiconductor devices in an IC device increases, and the number of integrated semiconductors per unit area increases with the year and the characteristic size of the chip 2 decreases year by year on the basis that the size of the chip 2 is kept unchanged, so that the power density per unit volume of an electronic component is higher and higher, and the heat flow density of the chip 2 is higher and higher, and the value of the heat flow density can reach 60-1000W/cm 2. Meanwhile, due to the uneven arrangement and integration of the semiconductor on the chip 2, the power distribution on the chip 2 becomes more and more uneven, and the problem of local hot spots is frequent.

Therefore, when the metal heat conduction layer 4 is provided, the heat generation problem at the hot spot position should be further taken away by concentrating the hot spot position and increasing the contact area between the metal heat conduction layer 4 and the chip 2. When the exhaust channel 5 is arranged, the hot spot position of the chip 2 should be avoided as much as possible, and the problem of insufficient contact area between the metal heat conduction layer 4 and the chip 2 at the hot spot position is avoided. Thereby effectively preventing the thermal failure problem of the chip 2.

In another aspect, the present application further provides a packaging method, including:

s1, providing a substrate 1, arranging a chip 2 on part of the surface of the substrate 1, and inversely installing the chip 2 on the substrate 1 to realize 100% corresponding connection of signals.

It should be noted that, the contact position between the chip 2 and the substrate 1 is provided with a bump 6, which is beneficial to electrically connecting the chip 2 and the substrate 1. After the bump 6 is formed, the method further comprises the following steps: and forming an underfill adhesive 8 on the bottom surface of the chip 2, and fixing the chip 2 on the substrate 1 through the underfill adhesive 8 filling and curing process. The bottom sealing adhesive 8 surrounds the salient points 6 and exposes the top surfaces of the salient points 6, so that the subsequent salient points 6 are electrically connected with the bottom surface of the chip 2. The underfill encapsulant 8 is used to relieve the shear stress between the chip 2 and the substrate 1 due to the difference in thermal expansion coefficients.

And S2, forming an exhaust channel 5 on the top surface of the chip 2 in one or more modes of slotting, blank space, attaching foreign matters and reducing roughness, and forming a plated metal layer by an electroplating process.

It should be noted that, before step S2, a pretreatment of chip 2 is further included, and a barrier layer, such as a barrier layer of sprayed or coated vanadium or titanium nickel, is disposed on the surface of chip 2 to block the diffusion of indium sheets in the material of chip 2.

And S3, forming a metal heat conduction layer 4 on the top surface of the electroplated metal layer, and applying heat conduction metal and soldering flux on the whole back of the chip 2.

S4, providing a heat dissipation cover 3, wherein the heat dissipation cover 3 covers the chip 2, an electroplating metal layer is arranged at the contact position of the heat dissipation cover 3 and the metal heat dissipation layer, and the electroplating metal layer is provided with the exhaust channel 5 formed by one or more modes of slotting, blank space, attaching foreign matters and reducing roughness;

in step S4, the heat dissipation cover 3 is pretreated, and the inner surface of the heat dissipation cover 3 is plated with nickel, so as to perform the functions of oxidation resistance, corrosion resistance, hardness enhancement and wear resistance.

S5, fixing the heat dissipation cover 3 on the substrate 1 in a through mounting manner; the heat-radiating cover 3 is fixed on the substrate 1 by an adhesive 9. When the adhesive 9 is applied, the adhesive 9 is applied discontinuously; where it is applied for fixation, and in areas where it is not applied, it can be used to vent the gas flow or gases generated during the subsequent high temperature reflow process out of the heat-dissipating cover 3.

S6, performing high-temperature reflow soldering, wherein the temperature adopted by the high-temperature reflow soldering is higher than the melting point of the metal heat conduction layer 4; the gas flow generated during the high-temperature reflow is discharged from the exhaust passage 5.

It should be noted that the air flow or gas generated by the flux in the metal heat conduction layer 4 is discharged through the air discharge channel 5, and the channel formed by the adhesive is used for discharging the air in the whole heat dissipation cover 3, unlike the action of the adhesive 9 which is discontinuously coated in step S5. The direction of the gas or air flow is from the inside of the metal heat conducting layer 4 through the air exhaust channel 5 into the inside of the heat radiating cover 3 and finally out through the channels of the adhesive site.

And S7, welding the heat dissipation cover 3, the chip 2 and the metal heat conduction layer 4 together through a high-temperature reflow soldering process.

The specific reflow soldering process comprises two steps, wherein in the first step, the heat dissipation cover 3, the chip 2 and the metal heat conduction layer 4 are soldered together through a high-temperature reflow soldering process; and the second step is to adopt a high-temperature reflow soldering process to solder the solder balls 7 at the bottom of the substrate 1. The temperature of the first high-temperature reflow soldering process is higher than the melting point of the metal heat conduction layer 4, and the temperature of the second high-temperature reflow soldering process is higher than the melting point of the solder balls 7. The solder ball 7 is made of tin, tin-silver alloy, tin-silver-copper alloy, tin-lead alloy or gold-containing alloy.

Example one

The gold plating area of the chip is divided by foreign matters (high-temperature adhesive tapes), the heat dissipation cover area is divided by grooves, and the shape of the exhaust channel is cross-shaped. After high-temperature reflow soldering, the result of the gold plating area is scanned by ultrasonic, and the result is shown in fig. 4, and about 2% of the cavity result is less than 10%, so that the expected effect is achieved.

The void results at 170 ℃ in FIG. 4(a) were 3.08%, and the void results at 240 ℃ in FIG. 4(b) were 2%.

Meanwhile, the grooves of the heat dissipation cover are detected, and flux residues are found, so that the grooves play a role in guiding out flux gas in the reflow soldering process.

Example two

The gold-plating area of the heat dissipation cover is provided with a groove, the gold-plating area of the chip is not provided with an exhaust passage, and the shape of the exhaust passage is cross-shaped. The result of scanning the gold-plated area of the chip by ultrasound is shown in fig. 5, and the result of the cavity is about 7.29% and less than 10%, so that the expected effect is achieved.

The voiding results were 2.62% at 170 ℃ in FIG. 5(a) and 7.29% at 240 ℃ in FIG. 5 (b).

EXAMPLE III

The gold plating area of the heat dissipation cover is provided with a transverse groove, the gold plating area of the chip is divided by foreign matters (high-temperature adhesive tape), and the dividing line on the chip is longitudinally arranged and is mutually vertical.

The result of scanning the gold-plated area of the chip by ultrasound is shown in fig. 6, and the result of the cavity is about 9.12% and less than 10%, so that the expected effect is achieved.

The void results at 170 ℃ in FIG. 6(a) were 3.71%, and the void results at 240 ℃ in FIG. 6(b) were 9.12%.

It should be noted that the chip package structure or the chip can be applied to electronic devices such as mobile phones, tablet computers, electronic books, computers, and the like, which need to mount a chip or a gold-backed chip. The above different embodiments may be cross-referenced. For example, while one embodiment has been described with some technical details of one aspect, reference may be made to the description of other embodiments.

It should be understood that, in the various embodiments of the present application, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

It should also be understood that the above-listed embodiments of the chip packaging method may be performed by a robot or a numerical control machining method, and that the device software or processes for performing the chip packaging method may be performed by executing computer program code stored in a memory.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated in the drawings that is solely for the purpose of facilitating the description and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and is therefore not to be construed as limiting the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Terms such as "disposed" and the like, as used herein, may refer to one element being directly attached to another element or one element being attached to another element through intervening elements. Features described herein in one embodiment may be applied to another embodiment, either alone or in combination with other features, unless the feature is otherwise inapplicable or otherwise stated in the other embodiment.

The present invention has been described in terms of the above embodiments, but it should be understood that the above embodiments are for purposes of illustration and description only and are not intended to limit the invention to the scope of the described embodiments. It will be appreciated by those skilled in the art that many variations and modifications may be made to the teachings of the invention, which fall within the scope of the invention as claimed.