CN100541782C - Package structure with stacked platform and packaging method thereof - Google Patents

Abstract

A package structure includes a first substrate, a first package, a second package and a sealant, wherein the first substrate has a first surface. The first package comprises a first chip and liquid sealant, wherein the first chip is arranged on the first substrate and is electrically connected with the first substrate through a first gold wire. The liquid sealant comprises a dam structure formed by a first sealant on the second surface of the first chip, an accommodating space surrounded by the dam structure, and a second sealant filled in the accommodating space surrounded by the dam structure, wherein the viscosity of the second sealant is smaller than that of the first sealant, the fluidity of the second sealant is larger than that of the first sealant, the liquid sealant covers the second surface of the first chip and covers a part of the first gold wire, and a platform is formed on the surface of the liquid sealant. The second package is disposed on the platform, and the encapsulant encapsulates at least a portion of the first surface of the first substrate, the first package, and the second package.

Description

Packaging structure with stacking platform and packaging method thereof

technical field

The present invention relates to a packaging structure, and in particular to a packaging structure with a stacking platform.

Background technique

With the evolution of chip packaging, the current packaging technology can complete extremely thin packaged chips. Thin chips can be packaged together with chip stacking technology to form a so-called package in package chip or multi chip module (MCM). Please refer to FIG. 1 , which is a cross-sectional view of a traditional repackaged chip structure. The package structure 100 includes a substrate 10 , a first package 20 , a second package 30 and a sealant 40 . The first package 20 includes a chip 21 , a chip 23 and a spacer 50 . The chip 21 is disposed on the substrate 10 and is electrically connected to the substrate 10 through gold wires 22 . The chip 23 is disposed above the chip 21 and is electrically connected to the chip 21 and the substrate 10 by gold wires 24 and 25 respectively. The second package 30 is disposed on the surface 51 of the spacer 50 . The second package 30 includes a substrate 31 and a chip 32 . The chip 32 is disposed on the substrate 31 and is electrically connected to the substrate 31 by gold wires 33 . The second package 30 is electrically connected to the substrate 10 by gold wires 35 . The sealing glue 34 covers the substrate 31 , the chips 32 and the gold wires 33 . The encapsulant 40 covers the surface 12 of the substrate 10 , the first package 20 and the second package 30 , and the bottom of the substrate 10 has a plurality of solder balls 11 .

However, the current chip stacking technology does not provide proper protection for semi-finished chips with gold wire bonds on the substrate. Therefore, the stacked chips are easy to tilt and the connected wires will be crushed, resulting in package failure. , Reduce production pass rate, make production cost increase. As shown in Figure 1, since the spacer 50 only contacts the second package 30 with the surface 51, due to insufficient contact area, it is easy to make the second package 30 tilt due to loss of balance or slight vibration or impact, and press the gold wire 22 , the gold wire 24 and the gold wire 25, resulting in packaging failure. Furthermore, due to the obstruction of the spacer 50 and the gold wire 22, the gold wire 24 and the gold wire 25, it is easy to cause the sealant 40 to not completely cover each component during the mold filling process, resulting in holes, especially between the chip 23 and the spacer 50. , It is very easy to have gas holes. This hole may cause a popcorn effect in the temperature change of the subsequent process and cause the sealant to break, thereby reducing the product yield.

Contents of the invention

In view of the above, the object of the present invention is to provide a packaging structure with a stacking platform, which uses a liquid sealant to form a stacking platform, provides chip placement, and can protect the linear position and bonding parts that need to be maintained.

According to the object of the present invention, a packaging structure is proposed, including a first substrate, a first package, a second package and a sealant. The first substrate has a first surface. The first package includes a first chip and a liquid sealant. The first chip is arranged on the first substrate and is electrically connected to the first substrate through the first gold wire. The liquid sealant includes a dam structure formed by the first glue on the second surface of the first chip, which encloses an accommodating space on the second surface of the first chip, and the dam structure surrounded by the dam structure The second colloid filled in the accommodating space, the viscosity of the second colloid is less than the first colloid, the fluidity is greater than the first colloid, the liquid sealant covers the second surface of the first chip, and covers part of the The first gold wire, the surface of the liquid sealant forms a platform. The second package is disposed on the platform, and the sealing glue covers at least part of the first surface of the first substrate, the first package and the second package.

According to still another object of the present invention, a packaging method is proposed. Firstly, a first substrate is provided, having a first surface. Next, the first chip is set on the first substrate. Then, the first chip and the first substrate are electrically connected with the first gold wire. Then, the first colloid is used to form a dam structure on the second surface of the first chip, which encloses an accommodating space on the second surface of the first chip; the second colloid is filled into the dam structure surrounded In the accommodating space, the viscosity of the second colloid is lower than that of the first colloid, and its fluidity is greater than that of the first colloid. The second colloid forms a liquid sealant with the dam structure, and the liquid sealant covers the first chip. The second surface and part of the first gold wire form a platform on the surface of the liquid sealant. Then, a second package is disposed on the platform. Then, encapsulating the first package, the second package and at least part of the first surface of the substrate with sealing glue.

In order to make the above-mentioned purposes, features, and advantages of the present invention more obvious and understandable, two embodiments are specifically cited below, together with the accompanying drawings, and are described in detail as follows:

Description of drawings

Fig. 1 is the structural sectional view of traditional re-packaging chip;

Fig. 2 is a side view of a package structure of the first embodiment of the present invention;

3A-3G are the packaging flowchart of the packaging structure of the first embodiment of the present invention; and

FIG. 4 is a side view of the package structure of the second embodiment of the present invention.

Description of main component marking

100, 200, 300: package structure

10, 31, 210, 231, 310, 331: substrate

11, 211, 311: solder balls

12, 51, 212, 226, 312, 326: surface

20, 220, 320: the first package

21, 23, 33, 221, 223, 232, 321, 323, 332: chips

22, 24, 25, 33, 35, 222, 224, 225, 233, 235, 322, 324, 325, 333, 335: gold wire

30, 230, 330: second package

34, 40, 234, 240, 334, 340: sealant

50: spacer

250, 350: Liquid sealant

251, 351: Platform

252, 352: Dam structure

253, 353: colloid

260, 360: silver glue

Detailed ways

Embodiment one

Please refer to FIG. 2 , which is a side view of a package structure according to the first embodiment of the present invention. The package structure 200 includes a substrate 210 , a first package 220 , a second package 230 and a sealant 240 . The first package 220 includes a chip 221 , a chip 223 and a liquid sealant 250 . The chip 221 is disposed on the substrate 210 and is electrically connected to the substrate 210 through gold wires 222 . The chip 223 is disposed above the chip 221 and is electrically connected to the chip 221 and the substrate 210 by gold wires 224 and gold wires 225 respectively.

The second package 230 is disposed on the platform 251 formed on the surface of the liquid encapsulant 250 . The second package 230 includes a substrate 231 and a chip 232 , the chip 232 is disposed on the substrate 231 and is electrically connected to the substrate 231 by gold wires 233 , and the second package 230 is electrically connected to the substrate 210 by gold wires 235 . The sealant 234 covers the substrate 231 , the chip 232 and the gold wire 233 . The encapsulant 240 covers the surface 212 of the substrate 210 , the first package 220 and the second package 230 , and a plurality of solder balls 211 are formed on the bottom of the substrate 210 .

Please refer to FIGS. 3A-3G , which are the packaging flowcharts of the packaging structure of the first embodiment of the present invention. First, please refer to FIG. 3A , a substrate 210 is provided, and the substrate 210 has a surface 212 , and then, a chip 221 is disposed on the surface 212 . Next, referring to FIG. 3B , a chip 223 is disposed on the surface 226 of the chip 221 . Then, referring to FIG. 3C , the chip 221 is electrically connected to the substrate 210 with gold wires 222 , the chip 223 is electrically connected to the chip 221 with gold wires 224 , and the chip 223 is electrically connected to the substrate 210 with gold wires 225 . Next, referring to FIG. 3D , a dam structure 252 is formed on the surface 226 of the chip 221 with a colloid with high viscosity and no random flow. Preferably, the dam structure 252 is formed around the surface 226 to enclose an accommodating space at the central part of the surface 226 .

Then, please refer to FIG. 3E , fill the containing space surrounded by the dam structure 252 with a less viscous, more fluid colloid 253, which is similar to silver colloid, and the colloid 253 and the dam structure 252 form a liquid state Sealant 250. The liquid encapsulant 250 covers the surface 226 of the chip 221 , a portion of the gold wire 222 , the chip 223 , the gold wire 224 and a portion of the gold wire 225 . Afterwards, the encapsulation structure is sent into an oven for baking. After the liquid sealant 250 is cured, the surface of the liquid sealant 250 is smoothed to form a platform 251 for placement, and the first package 220 is thus formed.

Next, referring to FIG. 3F , the second package 230 is bonded on the platform 251 with silver glue 260 . The second package 230 includes a substrate 231 , a chip 232 and a sealant 234 . The chip 232 is disposed on the substrate 231 and electrically connected to the substrate 231 by gold wires 233 . The encapsulant 234 covers the chip 232 , the gold wire 233 and the substrate 231 . The second package 230 is also electrically connected to the substrate 210 by gold wires 235 . After that, please refer to FIG. 3G , the sealant 240 covers at least part of the surface 212 of the substrate 210, the first package 220 and the second package 230. In this embodiment, the sealant 240 covers the entire surface 212 of the substrate 210 as an example. Explain it. Then, a plurality of solder balls 211 are formed on the bottom of the substrate 210 to complete the packaging step of the packaging structure 200 .

In the packaging structure 200 of this embodiment, the chips 221 and 223 and the gold wires 222 , 224 and 225 connected thereto are covered with a liquid encapsulant 250 . In this way, when the second package 230 is stacked on the chips 221 and 223 , the liquid encapsulant 250 covers the chips 221 and 223 . Therefore, the liquid sealant 250 can provide better protection to the chips 221 and 223 and the gold wires 222, 224 and 225 connected thereto than the spacer 50 shown in FIG. The wire type can avoid the short circuit of the gold wires 222, 224 and 225.

In addition, since the surface of the liquid encapsulant 250 forms a platform with an area equivalent to that of the chip 221 , it is used for placing the second package 230 . Compared with the spacer 50 formed above the chip 21 and on the side of the chip 23 in FIG. 1 , the surface of the platform 251 provided by the liquid encapsulant 250 is larger than the area of the spacer 50 , and the platform 251 can contact the second package 230 most of the bottom area. Therefore, the second package 230 of this embodiment can be placed on the platform 251 stably, which can prevent the second package 230 from being tilted.

Furthermore, since this embodiment uses a liquid sealant 250 with low viscosity and high fluidity to protect the chips 221 and 223, the probability of gas holes generated by the liquid sealant 250 is much higher than that formed by using the pouring process in FIG. 1 The probability of sealing glue 40 is small, so the packaging structure of this embodiment also has the advantage of improving the yield.

Embodiment two

Please refer to FIG. 4 , which is a side view of the package structure of the second embodiment of the present invention. The main difference between the package structure 300 of the present embodiment and the package structure 200 of the first embodiment lies in the portion where the liquid sealant contacts the substrate. The liquid encapsulant 350 of this embodiment not only completely covers the surface 326 of the chip 321 , but also partially covers the surface 312 of the substrate 310 . The method of forming the liquid encapsulant 350 is, for example, to firstly form a dam structure 352 on the surface 312 of the substrate 310 , and the dam structure 352 is located at the periphery of a certain distance from the chip 321 . After that, the glue 353 is filled into the accommodation space surrounded by the dam 352 to form a liquid sealant 350 covering part of the surface 312 of the substrate 310 and the surface 326 of the chip 321 . The connection relationship and formation steps of the remaining components are the same as those in the first embodiment, and will not be repeated here.

Because the area of the platform 351 of the sealant 350 formed in the second embodiment is larger than the area of the platform 251 of the sealant 250 in the first embodiment. Therefore, this embodiment can provide a larger platform 351 so that the second package 330 can be placed on the platform 351 more stably.

The packaging structure with a stacking platform disclosed in the above embodiments of the present invention covers the chip and its connecting gold wires with encapsulant, which can effectively protect the chip and its connecting gold wires, and form a platform on the surface of the liquid encapsulant , for another chip placement. Therefore, the packaging structure of the present invention can provide a better stacking platform for chips with a simple process, avoiding the damage caused by the stacked chips being tilted and crushing the connecting gold wires, which can improve the pass rate of products and reduce production costs, which are the advantages and characteristics of the present invention. .

In summary, although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications without departing from the spirit and scope of the present invention. Changes and improvements, so the protection scope of the present invention should be defined by the claims.

Claims (14)

1. A package structure, characterized in that it comprises: a first substrate having a first surface; A first package, including: a first chip, disposed on the first substrate, and electrically connected to the first substrate through a first gold wire; and The liquid sealant includes a dam structure formed by the first glue on the second surface of the first chip, which encloses an accommodating space on the second surface of the first chip, and the dam structure surrounded by the dam structure The second colloid filled in the accommodating space of the first colloid has less viscosity than the first colloid and greater fluidity than the first colloid, and the liquid encapsulant covers the second surface of the first chip and covers A part of the first gold wire forms a platform on the surface of the liquid encapsulant; a second package disposed on the platform; and The sealant covers at least part of the first surface of the first substrate, the first package and the second package. 2 . The package structure according to claim 1 , wherein the liquid encapsulant of the first package completely covers the first chip and partially covers the first surface of the first substrate. 3. The package structure according to claim 1, wherein the second package includes a second chip, a second substrate and a second gold wire, and the second chip is electrically connected to the second substrate through the second gold wire. connect. 4. The packaging structure according to claim 1, further comprising a third chip disposed on the second surface of the first chip, and the liquid encapsulant also covers the third chip. 5. The packaging structure according to claim 4, wherein the third chip is electrically connected to the first chip through at least one third gold wire, and the liquid encapsulant covers the third gold wire. 6 . The package structure according to claim 5 , wherein the third chip is electrically connected to the first substrate through a fourth gold wire, and the liquid encapsulant covers part of the fourth gold wire. 7. The package structure according to claim 1, wherein the second package is disposed on the platform through silver glue. 8. The package structure according to claim 1, wherein a plurality of solder balls are formed on the bottom of the first substrate. 9. A packaging method, characterized in that it comprises: providing a first substrate having a first surface; disposing a first package, disposing a first chip on the first substrate; electrically connecting the first chip and the first substrate with a first gold wire; forming a dam structure on the second surface of the first chip with the first colloid, which encloses an accommodating space on the second surface of the first chip; filling the containing space surrounded by the dam structure with the second colloid, the viscosity of the second colloid is lower than that of the first colloid, and its fluidity is greater than that of the first colloid, and the second colloid is compatible with the dam structure forming a liquid sealant, the liquid sealant covers the second surface of the first chip and part of the first gold wire, the surface of the liquid sealant forms a platform to form a first package; disposing a second package over the platform; and The first package, the second package and at least part of the first surface of the substrate are covered with encapsulant. 10. The packaging method according to claim 9, wherein the liquid sealant covers the second surface of the first chip and part of the first gold wire, and the surface of the liquid sealant forms the platform , the liquid sealant covers part of the first surface of the first substrate. 11. The packaging method according to claim 9, wherein the second package further comprises a second chip, a second substrate and a second gold wire, and in the step of setting the second package above the platform, It also includes: electrically connecting the second chip and the second substrate with the second gold wire. 12. The packaging method according to claim 9, further comprising: after disposing the first chip on the first substrate: disposing a third chip on the second surface of the first chip; Wherein, in the step of covering the second surface of the first chip and part of the first gold wire with the liquid encapsulant, and the surface of the liquid encapsulant forms the platform, the third chip is also covered with the liquid encapsulant. chip. 13. The packaging method according to claim 12, further comprising: after arranging the third chip on the second surface of the first chip: electrically connecting the third chip and the first chip with a third gold wire, and electrically connecting the third chip and the first substrate with a fourth gold wire; Wherein, the liquid encapsulant covers the third gold wire and part of the fourth gold wire. 14. The packaging method according to claim 9, wherein the step of disposing the second package on the platform further comprises: The second package is bonded on the platform with silver glue.

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