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Window Interposer PoP Disclosure Number: IPCOM000250208D
Publication Date: 2017-Jun-12
Document File: 4 page(s) / 288K

Publishing Venue

The Prior Art Database

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This is the abbreviated version, containing approximately 47% of the total text.

Window Interposer PoP


The three-dimensional (3D) Package-on-Package (PoP) has been developed to provide a low

package profile solution for high electrical performance and extreme low 3D stacking profile.


The subject invention discloses a window interposer PoP with an opening in the center of the

interposer. The opening of the interposer provides better encapsulation flows and more room

for the encapsulation so that no entrapped air or incomplete fill would be observed.

The subject invention provides not only a lower package profile from the narrow clearance

between interposer and die, but also can show high thermal performance by using high

conductive material mounted on the die back side and through the opening area of the

interposer. In addition, it is also possible to mount an additional conductive material or an

additional heat sink on the top of the embedded thermal material to further enhance the

thermal performance.

The first embodiment of the window interposer PoP is shown in Fig. 1. The first arrow refers

to the window interposer, which is made up of a single metal circuit or multilayer metal

circuits in organic or inorganic base material. The interposer has Ni/Au, Ni/Pd/Au or other

equivalent materials on the top of the exposed metal area to protect the circuit metals from

oxidation. The exposed metal on the bottom side of the interposer normally coated with OSP

or other similar protective materials. The second arrow refers to an optional stopper for

organic paste or film adhesive material, which is used to prevent bending of the interposer

during the following encapsulation process. The third arrow refers to wettable conductive

solder balls; Fig. 2 shows that pre-plated conductive pillars can also be used instead on the

bottom surface of the interposer or the top surface of the bottom substrate; alternatively,

pillars and balls are formed on both interposer and bottom substrate, respectively. The fourth

arrow refers to the encapsulation, filling the space between the top and bottom packages and

the opening of the interposer. The fifth arrow refers to the embedded die of various types,

such as flip chip, wire bond or a mixture of thereof. The sixth arrow refers to the bottom

substrate. The seventh arrow refers to solder balls as external connections; or, land type

terminals can also be adopted.

The opening of the window interposer is formed over the die to provide enough area for the

interconnections to the top package which normally has less fine bump pitch but needs more

planar area. In addition, the opening can also provide efficient cleaning of flux material for

flip-chip packages.

Window Interposer PoP

Fig. 1 The first embodiment of the window interposer PoP

Fig. 2 The window interposer or the bottom substrate with pre-plated Cu pillars

Fig. 3 shows the second embodiment of the thermal enhanced window interposer PoP with an

embedded heat sink. The eighth arrow refers to the adhesive material for adhering...