WO2018102962A1

WO2018102962A1 - Coaxial differential pair silicon through-hole structure

Info

Publication number: WO2018102962A1
Application number: PCT/CN2016/108563
Authority: WO
Inventors: 孟真; 刘谋; 张兴成; 阎跃鹏
Original assignee: 中国科学院微电子研究所
Priority date: 2016-12-05
Filing date: 2016-12-05
Publication date: 2018-06-14

Abstract

Disclosed is a coaxial differential pair silicon through-hole structure, relating to the technical field of chip encapsulation. By arranging an outer conductor shielding layer, differential signals transmitted in two separated inner conductor posts are completely isolated from peripheral signals, so that the transmission performance of the differential signals, especially, high-speed differential signals, can be improved. The coaxial differential pair silicon through-hole structure comprises a semiconductor silicon substrate and a silicon through-hole penetrating through the semiconductor silicon substrate, wherein an outer insulation layer is tightly pasted on an inner wall of the silicon through-hole; an outer conductor shielding layer is tightly pasted on the inner wall of the outer insulation layer; an inside insulation layer with two separated cylindrical spaces is tightly pasted on the inner wall of the outer conductor shielding layer; and two mutually separated inner layer conductor posts used for transmitting one pair of differential signals are arranged in the two separated cylindrical spaces.

Description

Coaxial differential pair silicon via structure

Technical field

The present invention relates to the field of chip packaging technologies, and in particular, to a coaxial differential pair silicon via structure.

Background technique

As the feature size of devices in semiconductor integrated circuits continues to decrease, the development of planar integrated circuits is facing challenges. The 3D packaging technology represented by through silicon via (TSV) packaging technology is an important development direction for high-density integration of integrated circuits. . The through-silicon via packaging technology directly forms vertical vias between the stacked dies to achieve interconnection between the chips. The packaging technology enables the chip to achieve maximum density stacking in the three-dimensional direction, greatly improving the speed of the chip, and reducing the power consumption of the chip, and has a very broad prospect in the future development direction of high performance and low power consumption of the semiconductor integrated circuit.

Through-silicon via packaging technology can integrate chips such as processors, memory, and high-speed data interfaces into the same package due to increased integration. With the rapid development of information technology, the processing and transmission rate of data continues to increase, and the clock frequency of processors, memory, and various data buses has reached 5 Gbps, and is still increasing. Since the waveform of the digital signal is a rectangular wave or a rectangular-like wave, the required transmission bandwidth is much higher than that of the same frequency analog signal, so the physical interconnection between the layers of the through-silicon via structure needs to be able to support the signal in a wide frequency band. Complete transmission.

The differential circuit can effectively suppress power supply noise, ground noise, electromagnetic coupling interference, and signal distortion. Therefore, in order to achieve better high-speed digital signal transmission performance in a wide frequency band, the differential structure has become the most versatile high-speed signal transmission carrier in digital circuits. Therefore, the differential pair interconnect structure is a necessary interconnect structure in the through silicon via structure.

The existing differential pair silicon via structure is generally two adjacent and independent vias. The pitch of the vias in the TSV package is small, typically on the order of hundreds of microns, ten microns to micrometers, and continues to decrease as technology advances. Since the distance between the via holes is small, and the semiconductor substrate material between the via structures is a semiconductor, the differential pair via structure of the prior art is susceptible to interference from signals in the peripheral vias when transmitting signals, and is differential. The signal in the through hole is also radiated to the surrounding through hole to cause interference to the surrounding signal. example For example, as shown in FIG. 1, the most commonly used differential pair via structure is composed of two adjacent vias "through hole 1" and "through hole 2" without any external signal isolation structure. This differential pair of through silicon via structures is susceptible to crosstalk from signals in adjacent via "vias 3". The signal amplitude and phase of the two signal vias of the peripheral signal crosstalk to the differential pair of vias are often inconsistent, which causes differential mode interference to the differential pair of through silicon vias. At the same time, the differential mode signal in the differential pair of through silicon vias also interferes with the signals in the surrounding vias. In order to solve the problem of signal crosstalk between the differential pair of silicon via structures and the periphery, as shown in FIG. 2, the signal isolation method generally adopted is to ground the periphery of the differential pair of through silicon vias "signal via 1" and "signal via 2". Through hole structure.

In the process of implementing the present invention, the inventors have found that at least the following technical problems exist in the prior art:

The signal isolation method in the differential-pair TSV structure in the prior art cannot completely isolate the differential signal from the peripheral signal; at the same time, the area of the semiconductor substrate which is required for such signal isolation is very large.

Summary of the invention

A coaxial differential pair silicon via structure is provided, which can completely isolate one pair of differential signals transmitted in two separate inner conductor columns from surrounding signals by providing an outer conductor shielding layer, thereby improving differential signals Especially the transmission performance of high-speed differential signals.

The present invention provides a coaxial differential pair silicon via structure including a semiconductor silicon substrate, wherein a through silicon via penetrating through the semiconductor silicon substrate is opened in a direction perpendicular to a surface of the semiconductor silicon substrate The inner wall of the through-silicon via is in close contact with the outer insulating layer, and the inner wall of the outer insulating layer is in close contact with the outer conductor shielding layer, and the inner wall of the outer conductor shielding layer is closely attached with two separated inner portions. The inner insulating layer of the columnar space is provided with two inner conductor posts separated from each other for transmitting one pair of differential signals in the two separate columnar spaces.

The coaxial differential pair silicon via structure provided by the present invention comprises a semiconductor silicon substrate, wherein a through silicon via penetrating through the semiconductor silicon substrate is opened in a direction perpendicular to a surface of the semiconductor silicon substrate. The inner wall of the through silicon via is in close contact with the outer layer of insulating layer, and the inner wall of the outer layer of insulating layer is closely attached to the outer layer. a body shielding layer, the inner wall of the outer conductor shielding layer is closely attached with an inner insulating layer in which two separated columnar spaces are formed, and two separated columnar spaces are provided with two separated ones for transmitting one pair The inner conductor post of the differential signal. Compared with the prior art, by providing the outer conductor shielding layer, the differential signals transmitted in the two separated inner conductor columns can be completely isolated from the surrounding signals, thereby improving the transmission performance of differential signals, especially high-speed differential signals. At the same time, the signal isolation method of the present invention can greatly reduce the area of the semiconductor substrate required as compared with the prior art signal isolation method for fabricating the ground via structure around the differential pair of through silicon vias. In summary, the coaxial differential pair silicon via structure of the present invention can save the area of the semiconductor substrate while improving differential signal transmission performance.

DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention. Other drawings may also be obtained from those of ordinary skill in the art in view of the drawings.

1 is a schematic structural view of a conventional differential pair of through silicon vias;

2 is a schematic structural view of a signal isolation manner of a conventional differential pair silicon via structure;

3 is a schematic structural view of an embodiment of a coaxial differential pair silicon via structure according to the present invention;

4 to FIG. 15 are diagrams showing a manufacturing process of a coaxial differential pair silicon via structure according to the present invention.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

As shown in FIG. 3, an embodiment of the present invention provides a coaxial differential pair silicon via structure, including a semiconductor a bulk silicon substrate, wherein a through silicon via hole penetrating through the semiconductor silicon substrate is opened in a direction perpendicular to a surface of the semiconductor silicon substrate, and an inner wall of the through silicon via is in close contact with an outer insulating layer, The inner wall of the outer layer of insulating layer is only affixed with an outer layer of a conductive shielding layer, and the inner wall of the outer layer of the outer layer of the outer layer of the outer layer of the outer layer of the outer layer of the outer layer of the outer layer of the inner layer of the outer layer of the outer layer of the outer layer of the inner layer There are two interconnected inner conductor posts for transmitting one pair of differential signals.

Wherein, the semiconductor silicon substrate is capable of being laminated in a package.

The coaxial differential pair silicon via structure provided by the present invention comprises a semiconductor silicon substrate, wherein a through silicon via penetrating through the semiconductor silicon substrate is opened in a direction perpendicular to a surface of the semiconductor silicon substrate. The inner wall of the through-silicon via is in close contact with the outer layer of insulating layer, and the inner layer of the outer layer of insulating layer is only adhered with an outer layer of conductor shielding layer, and the inner wall of the outer layer of the outer layer of conductor is closely attached with two separate columns. The inner insulating layer of the space, in which two separated inner conductor posts for transmitting one pair of differential signals are disposed in the two separate columnar spaces. Compared with the prior art, by providing the outer conductor shielding layer, the differential signals transmitted in the two separated inner conductor columns can be completely isolated from the surrounding signals, thereby improving the transmission performance of differential signals, especially high-speed differential signals. At the same time, the signal isolation method of the present invention can greatly reduce the area of the semiconductor substrate required as compared with the prior art signal isolation method for fabricating the ground via structure around the differential pair of through silicon vias. In summary, the coaxial differential pair silicon via structure of the present invention can save the area of the semiconductor substrate while improving differential signal transmission performance.

Wherein the outer insulating layer electrically isolates the outer conductor shielding layer from the semiconductor silicon substrate for preventing direct transmission of electrical signals in the outer conductor shielding layer to the semiconductor silicon substrate In the film. The outer conductor shielding layer encloses the inner conductor post inside thereof for limiting electromagnetic energy of the differential signal inside the outer conductor shielding layer, reducing transmission loss of the differential signal; and simultaneously forming the two inner layers The pair of differential signals transmitted by the conductor post are shielded from the signal shielding outside the outer conductor shield to prevent signal crosstalk between each other. The inner insulating layer and the outer conductor shielding layer The two inner conductor pillars are separated to prevent direct transmission of electrical signals in the inner conductor post to the outer conductor shield layer; meanwhile, the inner insulating layer is used to transmit differential pair signals. The two inner conductor posts are isolated to prevent direct transmission of electrical signals between the two inner conductor posts. The two inner conductor posts are independent of each other and are separated by an inner insulating layer for transmitting two signals of one set of differential signals.

Specifically, the coaxial differential pair silicon via structure of the present invention can improve differential signal transmission performance as follows:

The coaxial differential pair-on-silicon via structure of the present invention transmits high-speed, ultra-high-speed differential signals, and the electromagnetic energy of the signal is limited by the outer conductor shielding layer, and does not radiate electromagnetic energy into the surrounding semiconductor substrate. On the one hand, the energy loss of the forward transmission signal can be greatly reduced, and on the other hand, the differential signal inside the outer conductor shielding layer can be completely isolated from the signal outside the outer conductor shielding layer, and the signals inside and outside the outer conductor shielding layer can be prevented. Crosstalk between each other.

Preferably, the intersection of the two circular or elliptical through silicon vias in the parallel plane of the surface of the semiconductor silicon substrate has a maximum opening width perpendicular to the line connecting the center of the circle, and the outer opening layer is larger than the outer insulating layer and the outer layer. a sum of thicknesses of the layer conductor shielding layers, and a maximum opening width in a direction parallel to the line connecting the center of the semiconductor silicon substrate in a parallel plane of the intersection of the two circular or elliptical silicon through holes is smaller than the The circular or elliptical through silicon vias are perpendicular to the smaller diameter in the direction of the line connecting the center of the circle.

Preferably, the through silicon via is formed by two circular or elliptical through silicon vias that intersect each other, as shown in FIG.

Preferably, the outer insulating layer is made of an insulating material which is closed at the outer circumference in a direction parallel to the surface of the semiconductor substrate and has no intersection therebetween, as shown in FIG.

Preferably, the outer conductor shielding layer is made of a conductor which is closed at the outer circumference in a direction parallel to the surface of the semiconductor substrate and has no intersection therebetween, as shown in FIG.

Preferably, the inner insulating layer is made of an insulating material, the inner insulating layer is closed on the outer circumference in a direction parallel to the surface of the semiconductor substrate, and the outer periphery forms an intersection at the intermediate portion, as shown in FIG. .

Preferably, two mutually separated inner conductor posts for transmitting a pair of differential signals are made of a conductor, which is a solid conductor post, a hollow conductor post or a sleeve conductor with an internal filler column.

Preferably, the two mutually separated inner conductor posts for transmitting a pair of differential signals are respectively located in two separate columnar spaces formed inside the inner insulating layer, as shown in FIG.

As shown in FIG. 4 to FIG. 15 , the fabrication process of the coaxial differential pair silicon via structure in the above embodiment is compatible with the manufacturing process and process of the conventional conventional through silicon via structure. It is easy to make under the existing manufacturing process. The production process adopts the layer-by-layer production method from “outer layer to inner layer” as follows:

S1, a first circular through silicon via extending through the semiconductor silicon substrate is formed in a direction perpendicular to a surface of the semiconductor silicon substrate, as shown in FIG. 4, wherein the first circular through silicon pass The diameter of the hole is R, as shown in FIG.

S2, a second circular through-silicon via extending through the semiconductor silicon substrate is formed in a direction perpendicular to a surface of the semiconductor silicon substrate in a manner of partially overlapping the first circular through-silicon via. Forming through-silicon vias penetrating through the semiconductor silicon substrate, as shown in FIG. 6, wherein the intersection of the two circular through-silicon vias in the parallel plane of the surface of the semiconductor silicon substrate is perpendicular to the center line The maximum opening width in the direction is L, as shown in Figure 7, where L is less than R.

S3, forming an outer insulating layer on the inner wall of the through silicon via, the outer insulating layer being closed at the outer periphery in a direction parallel to the surface of the semiconductor substrate and having no intersection therebetween, as shown in FIG. Wherein the outer insulating layer has a thickness H1 as shown in FIG.

S4, forming an outer layer conductor shielding layer on the inner wall of the outer layer insulating layer, the outer layer conductor shielding layer being closed at an outer circumference in a direction parallel to a surface of the semiconductor substrate, and having no intersection therebetween, as shown in the figure 10, wherein the outer conductor shielding layer has a thickness H2, as shown in FIG. The sum of the thickness H1 of the outer insulating layer shown in FIG. 9 and the thickness H2 of the outer conductor shielding layer as shown in FIG. 11 is smaller than the semiconductor silicon base of the intersection of the two circular through silicon vias as shown in FIG. The parallel opening in the surface of the sheet is perpendicular to the maximum opening width L in the direction of the line connecting the center of the circle.

S5, forming an inner insulating layer internally formed with two separated columnar spaces on the inner wall of the outer conductor shielding layer, the inner insulating layer being closed on the outer circumference in a direction parallel to the surface of the semiconductor substrate And the outer periphery forms an intersection at an intermediate portion, as shown in FIG. 12, wherein the inner insulating layer has a thickness H3, and the intermediate overlapping portion of the inner insulating layer forms a thickness K in a direction of the center line connection. The partition wall is shown in Figure 13.

S6. Two inner conductor pillars separated from each other are disposed in two columnar spaces, wherein two inner conductor pillars and an outer conductor shield layer and an inner insulating layer between the two constitute a common The axial differential signal transmission structure is shown in Figures 14 and 15.

Although the above embodiment is an example of a coaxial differential pair-via via structure, the coaxial differential pair via structure can be applied not only to a semiconductor silicon substrate but also to other materials. A semiconductor substrate can be fabricated which is suitable for lamination interconnection in a package, such as a silicon germanium material semiconductor substrate, a gallium arsenide material semiconductor substrate, a gallium nitride material semiconductor substrate, or the like.

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. All should be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

A coaxial differential pair silicon via structure, comprising: a semiconductor silicon substrate, wherein a through silicon via the semiconductor silicon substrate is opened in a direction perpendicular to a surface of the semiconductor silicon substrate a hole, an inner wall of the through-silicon via is in close contact with an outer layer of insulating layer, the inner wall of the outer layer of insulating layer is in close contact with the outer layer of the conductor shielding layer, and the inner wall of the outer layer of the outer layer of the outer layer of the outer layer of the outer layer is formed The inner insulating layer of the columnar space is provided with two mutually separated inner conductor posts for transmitting one pair of differential signals.
The coaxial differential through silicon via structure of claim 1 wherein said semiconductor silicon substrate is adapted to be laminated interconnected within a package.
The coaxial differential through silicon via structure according to claim 1, wherein the through silicon via is formed by two circular or elliptical through silicon vias that intersect each other.
The coaxial differential pair-on-silicon via structure according to claim 3, wherein the intersection of the two circular or elliptical silicon vias on the surface of the semiconductor silicon substrate is perpendicular to the center of the circle The maximum opening width in the line direction is greater than the sum of the thicknesses of the outer insulating layer and the outer conductor shielding layer, and the surface of the semiconductor silicon substrate at the intersection of the two circular or elliptical silicon through holes is parallel The maximum opening width in the direction perpendicular to the line connecting the center of the circle is smaller than the smaller diameter of the two circular or elliptical through silicon holes perpendicular to the line connecting the center of the circle.
The coaxial differential through silicon via structure according to claim 1, wherein said outer insulating layer is made of an insulating material, said outer insulating layer being parallel to a surface of said semiconductor silicon substrate The upper perimeter is closed and there is no intersection in the middle.
The coaxial differential through silicon via structure according to claim 1, wherein said outer conductor shielding layer is made of a conductor, said outer conductor shielding layer being parallel to said semiconductor silicon substrate surface The outer circumference in the direction is closed and there is no intersection in the middle.
The coaxial differential through silicon via structure according to claim 1, wherein said inner insulating layer is made of an insulating material, said inner insulating layer being parallel to a surface of said semiconductor silicon substrate The upper circumference is closed and the outer circumference forms an intersection at the intermediate portion.
The coaxial differential through-silicon via structure according to claim 1, wherein the two inner conductor posts separated from each other for transmitting a pair of differential signals are made of a conductor, the inner conductor The column is a solid conductor post, a hollow conductor post or a telescopic conductor post with internal filling.
The coaxial differential pair-on-silicon via structure according to claim 8, wherein the two mutually separated inner conductor pillars for transmitting one pair of differential signals are respectively formed inside the inner insulating layer. Within 2 separate columnar spaces.