MULTILAYER INTERPOSER WITH HIGH BONDING STRENGTH

Disclosed is a multilayer interposer with high bonding strength, which is used in wafer testing. The multilayer interposer with high bonding strength comprises a plurality of thin-film layer structures overlapping sequentially. One of the thin-film layer structures comprises at least one first conductive blind via. An interconnection layer electrically connected to the first conductive blind via is configured on the surface of the one of the thin-film layer structures, and the interconnection layer comprises at least one head portion. Another one of the thin-film layer structures comprises at least one second conductive blind via. The bottom of the second conductive blind via contacts both of the corresponding head portion and part of the surface of the one of the thin-film layer structures. Thereby, the bonding strength between layers can be dramatically increased, and the resistance to the thermal shock can be also increased.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The instant disclosure relates to the field of wafer testing; in particular, to a multilayer interposer with high bonding strength.

2. Description of Related Art

With respect to the process flow in the semiconductor industry, it mainly includes four major steps which are the IC design, the wafer processing, the wafer testing and the wafer packaging. Generally, the step of wafer testing is to test the electric properties of each die of a wafer so as to abandon the defected dies. Specifically, during the wafer testing, the probe head of the probe card pierces to the pad on the die, which forms an electric contact. After that, the testing signals obtained via the probe head will automatically be transmitted to an automatic test equipment (ATE) to continue the following analysis and determination and obtain a test result of the electric properties of each die of a wafer. Thereby, the defected wafer generated during the upstream process will not continually be processed to be a product.

It is hard and costly to manufacture the probe cards, so currently the expensive probe card which includes an interposer and a probe card PCB, wherein the electric contact between the above two is usually formed by the solder ball welding. The cross section of the interposer of the connector is shown inFIG. 1. The interposer of this kind of connector may be damaged because of the following factors: 1) the thermal shock during the solder ball welding; 2) the stress variation during the electroplating process; and 3) the thermal shock during the desoldering and reworking, wherein the thermal shock is the major factor resulting in damage.

With the progress of the semiconductor process, the size of the semiconductor elements has become smaller, and the IC becomes much more delicate, such that it gets harder to do the wafer level measurement.

Usually, increase of the accuracy and the efficiency as the IC operates is required. The tests for wafers, semiconductor components and IC are also essential for lots of processes using new components and exploitations of new materials, especially the wafer level measurement.

There is room and necessity for the improvement regarding to the conventional interposer design, and how to make an improvement with a limited cost is also worth considering.

SUMMARY OF THE INVENTION

The achievement of the instant disclosure is to provide improved structures of the interface components for wafer testing and the interposer thereof, to get rid of the shortages resulting from the above electric contact made via the solder ball welding method and to improve the conventional operation

To achieve the above goals, the instant disclosure provides a multilayer interposer with high bonding strength, which is used in wafer testing. The multilayer interposer with high bonding strength comprises a core substrate and a thin-film layer structure. The core substrate has a conducting wire on its surface, and the conducting wire has at least one head portion. The thin-film layer structure overlaps the surface of the core substrate, and covers the conducting wire. The thin-film layer structure has at least one conductive blind via, and the bottom of the conductive blind via contacts both of the head portion and part of the surface of the core substrate.

The instant disclosure also provides a multilayer interposer with high bonding strength, which is used in wafer testing. The multilayer interposer with high bonding strength comprises a plurality of thin-film layer structures overlapping sequentially on the core substrate. One of the thin-film layer structures comprises at least one first conductive blind via. An interconnection layer electrically connected to the first conductive blind via is configured on the surface of the one of the thin-film layer structures, and the interconnection layer comprises at least one head portion. Another one of the thin-film layer structures comprises at least one second conductive blind via. The bottom of the second conductive blind via contacts the corresponding head portion and part of the surface of the one of the thin-film layer structures.

To sum up, in the multilayer interposer, the bottom of each conductive blind via contacts both of the corresponding head portion of the conducting wire and part of the surface of the core substrate. Thereby, the overlapping area will increase, and thus the bonding strength between layers can be increased, which further increases the resistance to thermal shock.

For further understanding of the instant disclosure, reference is made to the following detailed description illustrating the embodiments and embodiments of the instant disclosure. The description is only for illustrating the instant disclosure, not for limiting the scope of the claim.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The instant disclosure is related to a creative design of the connecting relationship of components in an interposer among the interface components for wafer testing. Compared with the stack-via structure, the instant disclosure has an improved resistance to thermal shock.

The First Embodiment

Refer toFIG. 2.FIG. 2shows a schematic diagram of a multilayer interposer with high bonding strength of the first embodiment of the instant disclosure. This embodiment provides a multilayer interposer with high bonding strength1, and it comprises a core substrate10and a thin-film layer structure20overlapping on the core substrate10.

Within this embodiment, the core substrate10can be a doubled-sided core substrate, and preferably, can be a core substrate structured by bounding layers, build-up layers or both of them. The core substrate10has an interconnect structure (not shown inFIG. 2). A conducting wire11is arranged on the surface of the core substrate10, and the conducting wire11is electrically connected to the interconnect structure of the core substrate10, wherein the conducting wire11has at least one head portion111. In addition, the interconnect structure can comprise the metal conducting wire (transverse direction), the contact window (the hole on the thin-film), the metal layer (longitudinal via filling plating) and the like. The design of the above element structures can be determined depending on the circuitry.

The thin-film layer structure20covers the conducting wire11, and comprises a thin-film dielectric layer21and at least one conductive blind via22formed on the thin-film dielectric layer21. The material of the thin-film dielectric layer21can be dry film or wet film, and also the material of the thin-film dielectric layer21can be a low-Dk material or a high-Dk material. The conductive blind via22can be formed by laser drilling or photolithography process, together with electroplating process or filling conducting material (such as the silver paste). It is worth mentioning that, the bottom of each conductive blind via22contacts both the corresponding head portion111and part of the surface of the core substrate10. Thereby, the overlapping area will increase, and thus the bonding strength between layers can be increased, which further increases the resistance to thermal shock.

As shown inFIG. 2, there are two thin-film layer structures20in the multilayer interposer1and each thin-film layer structure20has two conductive blind vias22, but in other embodiments of the instant disclosure, the amounts of the thin-film layer structure20and the conductive blind via22can be three or more than three. That is, the above amounts of the thin-film layer structure20and the conductive blind via22are examples for illustrating but not for restricting the instant disclosure. The amounts of the thin-film layer structure20and the conductive blind via22can be determined depending on the circuitry design for certain requirement, such as increasing the layout density.

In conjunction withFIG. 2andFIG. 3,FIG. 2andFIG. 3further illustrate the relationship between the conductive blind via22, the conducting wire11and the core substrate10. The conductive blind via22comprises an electrical contact portion221and a peripheral contact portion222extending from the electrical contact portion221. The electrical contact portion221is mainly configured to connect the corresponding head portion111, and the peripheral contact portion222is configured to connect part of the surface of the core substrate10.

Specifically, the bottom of the electrical contact portion221can be divided into a body region2211and a peripheral region2212, wherein the area and the shape of the body region2211correspond to the head portion111and the peripheral region2212at least surrounds part of the body region2211. The body region2211contacts the top of the head portion111. Additionally, the peripheral contact portion222protrudes from the peripheral region2212of the electrical contact portion221. The peripheral contact portion222contacts both of the side surface of the head portion111and part of the surface of the core substrate10.

Refer toFIG. 4.FIG. 4shows another schematic diagram of a multilayer interposer with high bonding strength of the first embodiment of the instant disclosure. The multilayer interposer1′ provided by this embodiment comprises a plurality of thin-film layer structures sequentially overlapping on the core substrate10, such as a first thin-film layer structure20′ and a second thin-film layer structure20″. It is worth mentioning that, the conductive blind via22can be also applied to the adjacent first thin-film layer structure20′ and second thin-film layer structure20″.

In detail, the first thin-film layer structure20′ has at least one first conductive blind via22′, and an interconnection layer23is arranged on the surface of the first thin-film layer structure20′, wherein the interconnection layer23is electrically connected to the first conductive blind via22′. The interconnection layer23has at least one head portion231. The second thin-film layer structure20″ has at least one second conductive blind via22″ which is unaligned with the corresponding first conductive blind via22′. The second thin-film layer structure20″ covers the interconnection layer23, and the bottom of the second conductive blind via22″ contacts both of the corresponding head portion231and part of the surface of the first thin-film layer structure20′. Thereby, the multilayer interposer1provided by the instant disclosure has a better resistance to thermal shock.

In conjunction withFIGS. 4-6, in the multilayer interposer1, a solder mask layer30and a plurality of electrical connection pads40are arranged on the most outer thin-film layer structure (the second thin-film layer structure20″) to electrically connect the PCB of the test equipment or the wafer on the carrier (not shown) and to proceed with the staged tests during the wafer manufacturing or the final test as the wafer packaging has been finished. The electrical connection pads40serving as wafer test points are exposed from the solder mask layer30, wherein each wafer test point41is arranged on and electrically connected to a corresponding conductive blind via22.

In this embodiment, the electrical connection pads40are arranged in a matrix (as shown inFIG. 6) or in a wraparound way (as shown inFIG. 5), and a solder ball can be arranged on each wafer test point as the conductive contact for wafer testing. It should be noted that, the arrangement, the amount, the shape and the size of the electrical connection pads40can be determined depending on the circuitry design for certain requirements, such as increasing the layout density, but it is not limited herein.

The Second Embodiment

In conjunction withFIG. 7andFIG. 8,FIG. 7shows a schematic diagram of a multilayer interposer with high bonding strength of the second embodiment of the instant disclosure, andFIG. 8shows a schematic diagram of the connection relationship among the conductive blind via, the conducting wire and the core substrate in a multilayer interposer with high bonding strength of the second embodiment of the instant disclosure shown inFIG. 7. The difference between this embodiment and the above embodiment is that, in the thin-film layer structure20, the diameter D of at least one conductive blind via22is larger than the width W of the corresponding head portion111.

Specifically, the bottom of the electrical contact portion221can be divided into a body region2211and a peripheral region2212, wherein the area and the shape of the body region2211correspond to the head portion111and the peripheral region2212entirely surrounds the body region2211. Accordingly, the side face of the head portion111is entirely clad with the peripheral contact portion222of the conductive blind via22, and the peripheral contact portion222contacts part of the surface of the core substrate10.

To sum up, compared with the prior art, in the multilayer interposer of the instant disclosure, the bottom of each conductive blind via contacts both of the corresponding head portion of the conducting wire and part of the surface of the core substrate. Thereby, the overlapping area will increase, and thus the bonding strength between layers can be increased, which further increases the resistance to thermal shock.

The descriptions illustrated supra set forth simply the preferred embodiments of the instant disclosure; however, the characteristics of the instant disclosure are by no means restricted thereto. All changes, alterations, or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the instant disclosure delineated by the following claims.