Structure of multiple coaxial leads within single via in substrate and manufacturing method thereof

This application claims the priority benefit of Taiwan application serial no. 97151842, filed on Dec. 31, 2008. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification.

1. Technical Field

The present disclosure relates to a structure of leads within a via in a substrate, and more particularly to a structure of multiple coaxial leads within a single via in a substrate.

2. Description of Related Art

As the manufacturing process of semiconductors becomes more and more precise, in the future manufacturing process below 45 nm, the problem of severe impedance mismatch inevitably occurs when it intends to guide an ultra-thin lead with a width lower than 45 nm to pass through a via with an aperture larger than 1 μm and connect the ultra-thin lead to another ultra-thin lead, and thereby, it fails to achieve a high-speed signal transmission. However, if a plurality of leads is disposed in the via to solve the above problem, the problem of crosstalk among the plurality of leads turns to occur.

For example, U.S. Pat. No. 5,587,119 discloses a coaxial lead structure. FIGS. 1A to 1F are schematic cross-sectional views of a coaxial lead structure manufactured by a method provided in U.S. Pat. No. 5,587,119. First, referring to FIG. 1A , a substrate 102 is provided. Then, a first via 104 is disposed in the substrate 102 , the substrate 102 has an upper surface 106 and a lower surface 108 , and the first via 104 has a via wall surface 110 , as shown in FIG. 1B . Next, referring to FIG. 1C , a surface metal layer 112 and a via wall metal layer 114 are formed, and then a second via 116 with the via wall metal layer 114 is obtained. Afterward, an insulating material 118 is filled in the second via 116 , as shown in FIG. 1D . Then, as shown in FIG. 1E , a third via 120 is disposed in a center of the insulating material 118 . Finally, as shown in FIG. 1F , metal leads 122 are filled in the third via 120 , so that the via wall metal layer 114 , the insulating material 118 , and the central metal leads 122 constitute the coaxial lead structure 100 . In the coaxial lead structure 100 , the via wall metal layer 114 may be grounded, and as the central metal leads 122 are surrounded thereby, the metal leads 122 are under good electromagnetic shielding, thus eliminating the problem of crosstalk.

U.S. Pat. No. 5,421,083 also discloses a coaxial lead structure. FIG. 2 is a schematic cross-sectional view of a coaxial lead structure manufactured by a method provided in U.S. Pat. No. 5,421,083. The coaxial lead structure 200 includes a substrate 202 , a first conductive layer 204 , a second conductive layer 206 , a first insulating layer 208 , and a second insulating layer 210 . In this patent, both the first conductive layer 204 and the second conductive layer 206 pass through a via simultaneously to transmit signals.

U.S. Pat. No. 6,943,452 further discloses a coaxial lead structure. FIG. 3 is a schematic cross-sectional view of a coaxial lead structure provided in U.S. Pat. No. 6,943,452. The coaxial lead structure 300 includes a cylindrical lead 304 capable of being placed in a conductive tube 306 and electrically connected to the conductive tube 306 . The conductive tube 306 is disposed in a composite substrate 302 , and surrounded by a plurality of grounding devices 308 . However, the grounding devices 308 are not continuous from top to bottom.

U.S. Pat. No. 7,404,250 further discloses a coaxial lead structure. FIG. 4 is a schematic cross-sectional view of a coaxial lead structure provided in U.S. Pat. No. 7,404,250. The coaxial lead structure 400 includes a first lead 404 , insulating layers 406 surrounding the first lead 404 , and second leads 410 and conductive layers 408 surrounding the insulating layers 406 . The conductive layers 408 are electrically connected to the first lead 404 . Similar to U.S. Pat. No. 5,421,083, this patent provides a solution that both the first lead 404 and the second leads 410 pass through a via simultaneously to transmit signals.

In addition, U.S. Pat. No. 6,943,452 and ROC Patent No. I248330 respectively disclose a lead structure including a grounding device, so as to reduce the crosstalk among the leads. U.S. Pat. No. 7,129,567 discloses a solution of disposing a plurality of leads within a single via.

As the manufacturing process of semiconductors becomes increasingly precise, it is an inevitable trend to manufacture multiple coaxial leads within a single via in the future, which may increase the circuit density in a unit of area, and make the products thinner, lighter, shorter, and smaller. However, seen from the above, the prior art discloses the manufacturing of one coaxial lead in a single via or the manufacturing of a plurality of leads in a single via, and the problem of crosstalk still exists. Therefore, manufacturing a plurality of coaxial leads in a single via while avoiding the problem of crosstalk is needed urgently.

In an exemplary embodiment, the manufacturing method includes the following steps. First, a first substrate and a second substrate are provided, a first conductive layer is disposed on a surface of the first substrate, and a second conductive layer is disposed on a surface of the second substrate. After that, the first substrate is disposed on the second conductive layer. Next, a via is formed in the first substrate, and a surrounding conductor is disposed in the via. Then, the surrounding conductor is patterned to form a plurality of ring-shaped trenches, and at least one lead is formed in each of the ring-shaped trenches. Finally, an insulating material is filled in the ring-shaped trenches.

The present disclosure is further directed to a structure of multiple coaxial leads within a single via in a substrate. The structure includes a substrate formed with at least one via, and multiple coaxial leads are disposed in the via. Each group of the coaxial leads at least includes a surrounding conductor, an annular insulating material, and a lead.

In order to make the aforementioned and other features of the present disclosure comprehensible, exemplary embodiments accompanied with figures are described in detail below.

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments and, together with the description, serve to explain the principles of the invention.

FIGS. 1A to 1F are schematic cross-sectional views of a coaxial lead structure manufactured by a method disclosed in U.S. Pat. No. 5,587,119.

FIG. 2 is a schematic cross-sectional view of a coaxial lead structure manufactured by a method disclosed in U.S. Pat. No. 5,421,083.

FIG. 3 is a schematic cross-sectional view of a coaxial lead structure disclosed in U.S. Pat. No. 6,943,452.

FIG. 4 is a schematic cross-sectional view of a coaxial lead structure disclosed in U.S. Pat. No. 7,404,250.

FIG. 5A is a schematic top view of a structure of leads within a via in a substrate according to an exemplary embodiment.

FIG. 5B is a schematic cross-sectional view of a structure of leads within a via in a substrate according to an exemplary embodiment.

FIGS. 6A to 6L are schematic cross-sectional views of a structure of leads within a via in a substrate manufactured according to an exemplary embodiment.

FIG. 7 is a schematic view of a structure of leads within a via in a substrate according to an exemplary embodiment.

FIG. 8 is a schematic view of a structure of leads within a via in a substrate according to an exemplary embodiment.

Reference will now be made in detail to the present exemplary embodiments, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

The structure of leads within a via in a substrate and a manufacturing method thereof provided by the present disclosure are described below through different exemplary embodiments.

FIGS. 5A and 5B are respectively a schematic top view and a schematic cross-sectional view of a structure of leads within a via in a substrate according to an exemplary embodiment. A substrate 502 has a via 504 . The via 504 includes a surrounding conductor 506 and two leads 508 , and the surrounding conductor 506 surrounds the leads 508 . An insulating material 510 is disposed between the surrounding conductor 506 and the leads 508 for insulating. Top ends and bottom ends of the leads 508 are exposed, so as to be electrically connected to conductive layers beside the substrate 502 . A conductive layer 512 is electrically connected to the surrounding conductor 506 , so as to enable the surrounding conductor 506 to be connected to a voltage potential such as a ground potential. As the leads 508 are surrounded by the surrounding conductor 506 , the leads 508 are under good electromagnetic shielding.

FIGS. 6A to 6L are schematic cross-sectional views of a structure of leads within a via in a substrate manufactured according to an exemplary embodiment. First, as shown in FIG. 6A , a first substrate 602 and a second substrate 622 are provided, a first conductive layer 612 is disposed on a surface of the first substrate 602 , and a second conductive layer 624 is disposed on a surface of the second substrate 622 . A first via 614 is also formed. The first substrate 602 is disposed on the other surface of the second conductive layer 624 . Next, referring to FIG. 6B , a surrounding conductor 606 is disposed to fill the first via 614 , and the surrounding conductor 606 is electrically connected to the first conductive layer 612 and the second conductive layer 624 . The surrounding conductor 606 and the second conductive layer 624 there-below are patterned to form ring-shaped trenches 610 , and the ring-shaped trenches 610 have leads 608 L and leads 608 R therein (which are originally a portion of the surrounding conductor 606 ), as shown in FIG. 6C . Afterward, insulating materials 610 D are used to fill the ring-shaped trenches 610 and surfaces of the surrounding conductor 606 , the first conductive layer 612 , the leads 608 L, and the leads 608 R, and then the insulating materials 610 D are patterned to expose the surfaces of the leads 608 L and the leads 608 R, as shown in FIG. 6D . Next, referring to FIG. 6E , a third conductive layer 616 is disposed and patterned to be electrically connected to the leads 608 L. Then, referring to FIG. 6F , an insulating material layer 618 D is disposed and patterned to expose the top end of the leads 608 R. After that, a fourth conductive layer 620 is disposed and patterned to be electrically connected to the leads 608 R, as shown in FIG. 6G .

Next, a circuit below the substrate 602 is formed. Referring to FIG. 6H , the second substrate 622 is removed, and an insulating material layer 626 D is disposed and patterned to expose the other surfaces of the leads 608 L and the leads 608 R, as shown in FIG. 6I . Afterward, a fifth conductive layer 628 is disposed and patterned to be electrically connected to the leads 608 L, as shown in FIG. 6J . Referring to FIG. 6K , an insulating material layer 630 D is disposed and patterned to expose the other surface of the leads 608 R. A sixth conductive layer 632 is disposed and patterned to be electrically connected to the leads 608 R, as shown in FIG. 6L . In addition, among the above first to sixth conductive layers, the first conductive layer 612 and the second conductive layer 624 enable the surrounding conductor 606 to be electrically coupled to the ground. Further, the third conductive layer 616 , the fourth conductive layer 620 , the fifth conductive layer 628 , and the sixth conductive layer 632 are respectively used to electrically couple the leads 608 L and the leads 608 R to other signals or potentials.

This exemplary embodiment discloses four signal conductive layers and two ground conductive layers, but the present invention is not limited hereby, and the number of the signal conductive layer and the ground conductive layer may be varied.

FIG. 7 is a schematic view of a structure of leads within a via in a substrate according to an exemplary embodiment. Referring to FIG. 7 , a multi-layer structure is manufactured in the present disclosure, and the structure is respectively connected to different conductive layers. A first surrounding conductor 706 A, a second surrounding conductor 706 B, and a third surrounding conductor 706 C are all disposed in a first via of the present disclosure, and respectively have first leads 708 A, second leads 708 B, and third leads 708 C, so as to be connected to a first conductive layer 716 A, a second conductive layer 716 B, and a third conductive layer 716 C, respectively. The first to third conductive layers may be electrically coupled to other signals or potentials, respectively. Further, the first surrounding conductor 706 A, the second surrounding conductor 706 B, and the third surrounding conductor 706 C are stacked together like cakes, among which the first surrounding conductor 706 A has the largest radius, the third surrounding conductor 706 C has the smallest radius, and the three surrounding conductors are all electrically coupled to the ground via a fourth conductive layer 712 .

This exemplary embodiment discloses three signal conductive layers, one ground conductive layer, and three surrounding conductors, but the present invention is not limited hereby, and the number of the signal conductive layer, the ground conductive layer, and the surrounding conductor may be varied.

FIG. 8 is a schematic view of a structure of leads within a via in a substrate according to an exemplary embodiment. Referring to FIG. 8 , surrounding conductors of the present disclosure may be electrically connected to different ground conductive layers, respectively. A first surrounding conductor 806 A, a second surrounding conductor 806 B, and a third surrounding conductor 806 C are all located within a first via of the present disclosure, and respectively have first leads 808 A, second leads 808 B, and third leads 808 C, so as to be connected to a first conductive layer 816 A, a second conductive layer 816 B, and a third conductive layer 816 C, respectively. The conductive layers 816 A, 816 B and 816 C may be electrically coupled to other signals or potentials, respectively. Further, the first surrounding conductor 806 A, the second surrounding conductor 806 B, and the third surrounding conductor 806 C are stacked together like cakes, among which the first surrounding conductor 806 A has the largest radius, and the third surrounding conductor 806 C has the smallest radius. The three surrounding conductors are electrically coupled to the ground via a fourth conductive layer 812 A, a fifth conductive layer 812 B, and a sixth conductive layer 812 C, respectively. In this exemplary embodiment, the fourth conductive layer 812 A, the first lead 808 A, the fifth conductive layer 812 B, the second lead 808 B, the sixth conductive layer 812 C, and the third lead 808 C are stacked, so as to achieve more desirable electrical effects.

This exemplary embodiment discloses three signal conductive layers, three ground conductive layers, and three surrounding conductors, but the present invention is not limited hereby, and the number of the signal conductive layer, the ground conductive layer, and the surrounding conductor may be varied.

In the above exemplary embodiments, the via, the surrounding conductors, and the leads are all round in shape, but the present invention is not limited hereby, and the via, the surrounding conductors, and the leads may be square-shaped or in other shapes.

In addition, in the above exemplary embodiments, the conductive layers, the surrounding conductors, and the leads may be made of metals or other conductive materials.

The above exemplary embodiments provide a structure of leads within a via in a substrate to eliminate the problem of crosstalk. Therefore, the structure can be applied to a structure with a vertical interconnection between a circuit on a surface of the substrate and a circuit on the other surface of the substrate and a manufacturing process thereof, and may also be applied to a manufacturing process of an integrated circuit (IC) and a manufacturing process of a multi-layer circuit, such as a circuit board.

In the above exemplary embodiments, a plurality of coaxial leads is manufactured in a single via. The coaxial leads include leads for electrically connecting circuits located on different surfaces of the via. The surrounding conductors wrap the leads, and provide an electromagnetic shielding effect to eliminate the problem of crosstalk. In addition, the surrounding conductors may be grounded.

In the structure of leads within a via in a substrate according to the above embodiments, as the single via has a plurality of coaxial leads, the problem of impedance mismatch is avoided.

The structure of leads within a via in a substrate according to the above exemplary embodiments may be adapted to electrically connect a plurality of circuits on a surface of the substrate to a plurality of circuits on the other surface of the substrate, so as to increase the circuit density in a unit of area.

Moreover, the above exemplary embodiments provide a manufacturing method, which is adapted to manufacture the above structure of leads within a via in a substrate. In an exemplary embodiment, a plurality of patterned insulating material layers and conductive layers is further disposed on the surfaces of the first conductive layer and the second conductive layer to increase the circuit density, and the conductive layers on different surfaces of the substrate are electrically connected through the leads within the via.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the embodiments described be considered as exemplary only, with the true scope of the embodiments being indicated by the following claims and their equivalents.