JP2006024653A - Through substrate and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a through electrode for excluding noise by crosstalk. <P>SOLUTION: A through substrate comprises a silicon substrate 10 having a through hole 19 penetrating a front 11 and a backside 12, a silicon oxide film 13 provided along the inner wall surface of the through hole 19, Zn and Cu layers 14, 15 formed on the inner wall surface of the silicon oxide film 13, and a Cu-plated layer 18 grown from a Cu seed layer 17 via an insulating layer 16 in-between along the inner wall surface of the Zn and Cu layers 14, 15. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a through-hole substrate and a manufacturing method thereof, and more particularly, to a through-hole substrate that can be used as a signal transmission path and a manufacturing method thereof.

  In the conventional multilayer wiring circuit board, when the wiring layer is densified, the signal lines are close to each other, so that crosstalk noise is generated between the signal wirings, and the circuit drive element is caused to malfunction. There was a problem. One method for solving such a problem is described in, for example, Japanese Patent Application Laid-Open No. 2004-63725 (Patent Document 1).

According to the publication, a coaxial line having a coaxial structure is formed inside a substrate and used as a signal wiring layer.
JP 2004-63725 A (paragraph number 0004, FIG. 1 etc.)

  Conventional methods for eliminating crosstalk noise have been performed as described above. In Patent Document 1, noise is eliminated by arranging a coaxial structure parallel to the substrate and arranging it in the vicinity of the ground potential or power supply potential layer, so that the configuration in the substrate is complicated. There was a problem of becoming.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a through-hole substrate that can eliminate noise due to crosstalk and a method for manufacturing the same.

A through substrate according to the present invention includes a substrate having a through hole penetrating the front and back surfaces, a first conductive layer provided along an inner wall surface of the through hole, and having an inner wall surface therein, and an inner portion of the first conductive layer. A second conductive layer is provided along the wall surface with an insulating layer interposed therebetween.

  Preferably, the first conductive layer operates as a shield line, and the second conductive layer operates as a signal line.

  The substrate may be an insulator substrate or a semiconductor substrate.

  When the substrate is a semiconductor substrate, an insulating layer is further included between the inner wall surface of the through hole and the first conductive layer.

  The through hole may be a through hole of an interposer.

  In another aspect of the present invention, a method for manufacturing a through-hole substrate includes a step of preparing a substrate having front and back surfaces, a step of forming a through-hole in the substrate, and an inner wall along the inner wall surface of the through-hole. Forming a first conductive layer having a wall surface, and forming a second conductive layer along an inner wall surface of the first conductive layer with an insulating layer therebetween.

  Preferably, the step of preparing the substrate having the front and back surfaces includes the step of preparing a semiconductor substrate, and before forming the first conductive layer having the inner wall surface along the inner wall surface of the through hole. The method further includes forming an insulating layer having an inner wall surface along the inner wall surface, and then forming a second conductive layer along the inner wall surface of the insulating layer.

  The through substrate according to the present invention is provided with a first conductive layer provided along the inner wall surface of the through hole penetrating the front and back surfaces, and an insulating layer interposed along the inner wall surface of the first conductive layer. A second conductive layer. Since the second conductive layer is surrounded by the first conductive layer through the insulating layer inside the through hole, a configuration of a coaxial cable with improved shielding is obtained. As a result, it is possible to provide a through substrate that can eliminate noise due to crosstalk.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a step of manufacturing a through-hole substrate according to an embodiment of the present invention. Here, the through substrate refers to a substrate having a through hole from the front surface to the back surface of the substrate, and includes a printed circuit board (including flexible) and an interposer (including a silicon interposer).

  Referring to FIG. 1, first, a silicon substrate (penetrating substrate) 10 having a front surface 11 and a back surface 12 and having a plurality of through holes 19 penetrating between both surfaces is prepared. It is assumed that the entire substrate 10 is covered with the silicon oxide film 13. Next, for example, a Zn layer 14 is formed in the through hole 19 and around the front and back surfaces by electroless plating (FIG. 1A). Next, a Cu layer 15 is similarly formed on the Zn layer 14 by electroless plating (FIG. 1B, these layers become the first conductive layers). Next, the insulating layer 16 is formed on the Cu layer 15 by sputtering, for example. The insulating layer 16 is not limited to sputtering, and a silicon oxide film or a silicon nitride film may be formed by CVD, or an electrodeposition resin may be formed. Examples of the electrodeposition resin include PTFE, resist, polyimide, polyamide, and the like.

  In addition, although sputtering and CVD need to prepare a vacuum apparatus, since electrodeposition resin does not need such, it is preferable.

  Next, on the back surface 12 side of the through-hole 19, for example, a Cu seed layer 17 is provided, which is formed as an electrode for electric field or electroless plating, and is composed of an insulating layer 16 from this electrode toward the front surface 11 side. A conductive layer (second conductive layer) 18 is formed by growing a plated layer inside the through-hole (FIG. 1D).

  As a result, the through hole 19 of the substrate 10 is filled with the conductive layer 18, the insulating layer 16, and the conductive layers 15 and 14 from the center thereof, and a coaxial cable shape with improved shielding is obtained. This shape is a via hole having the shape of a coaxial cable that can reduce noise, reduce parasitic capacitance, and transmit signals at a high speed. This shape is hereinafter referred to as a coaxial via.

  Next, another embodiment of the present invention will be described. In the above embodiment, an example in which a silicon substrate is used has been described. However, in this embodiment, an insulating substrate such as a glass substrate or a sapphire substrate is used as the through substrate.

  FIG. 2 is a diagram corresponding to FIG. 1 when such an insulating substrate is used. Referring to FIG. 2, in this embodiment, since the through substrate is an insulating substrate, it is necessary to provide an insulating layer 13 such as an oxide film along the inner wall of the through hole as in the previous embodiment. There is no.

  The other parts are the same as those in the previous embodiment, and the description thereof is omitted.

  In addition, this through substrate may be applied to an interposer having a plurality of through holes.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

    The through substrate according to the present invention can be advantageously used as a substrate having a function similar to that of a coaxial cable.

It is a figure which shows the manufacturing method of a penetration substrate for every step at the time of using a semiconductor substrate as a board | substrate. It is a figure which shows the manufacturing method of a penetration substrate for every step at the time of using an insulating substrate as a board | substrate.

Explanation of symbols

10 substrate, 11 surface, 12 back surface, 13 oxide film, 14 Zn plating layer, 15 Cu plating layer, 16 insulating layer, 17 seed layer, 18 conductive layer, 19 through-hole.

Claims (7)

A substrate having a through hole penetrating the front and back surfaces;
A first conductive layer provided along an inner wall surface of the through-hole and having an inner wall surface inside;
A through substrate having a second conductive layer provided along an inner wall surface of the first conductive layer with an insulating layer interposed therebetween. The through-hole wiring board according to claim 1, wherein the first conductive layer operates as a shield line, and the second conductive layer operates as a signal line. The through substrate according to claim 1, wherein the substrate includes an insulating substrate. The substrate includes a semiconductor substrate;
The through substrate according to claim 1, further comprising an insulating layer between an inner wall surface of the through hole and the first conductive layer. The through substrate according to claim 1, wherein the through hole is a through hole of an interposer. Preparing a substrate having front and back surfaces;
Forming a through hole in the substrate;
Forming a first conductive layer having an inner wall surface along the inner wall surface of the through hole;
Forming a second conductive layer along an inner wall surface of the first conductive layer via an insulating layer therebetween. Preparing the substrate having the front and back surfaces comprises preparing a semiconductor substrate;
Forming an insulating layer having an inner wall surface along the inner wall surface of the through hole before forming the first conductive layer having the inner wall surface along the inner wall surface of the through hole; The manufacturing method of the penetration substrate of Claim 6 including the step of forming the said 2nd conductive layer along the inner wall face of an insulating layer including after that.

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