JP2013187247A - Interposer and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interposer capable of connecting terminals by the shortest electrical path.SOLUTION: An interposer 1 according to the present invention includes: a transparent insulator 11; a first electrode group 12 composed of a plurality of electrodes arranged on a first surface 11a of the transparent insulator 11; a second electrode group 13 composed of the same number of electrodes as the first electrode group 12 which are arranged on a second surface 11b opposite to the first surface 11a of the transparent insulator 11; and an electrode group 14 which penetrates the transparent insulator 11 and connects corresponding electrodes of the first electrode group 12 and the second electrode group 13 at the shortest distance.

Description

  The present invention relates to an interposer and a method for manufacturing the interposer, and more particularly to an interposer in which corresponding terminals are connected by a linear electric circuit and a method for manufacturing the interposer.

  In recent years, semiconductor integrated circuits (ICs) have been further miniaturized and highly integrated, and external connection terminals have also been increased in density.

  Increasing the density of the terminals formed on the mounting substrate in response to the increase in the density of the external connection terminals of the IC not only increases the manufacturing cost, but also increases the mounting technology.

  For this reason, an interposer that is installed between an IC and a mounting board and converts the terminal pitch of the IC into the terminal pitch of the mounting board has already been developed (see, for example, Patent Document 1).

  The interposer is also used for PoP (package on package) or PiP (package in package) for stacking ICs themselves.

JP 2011-086767 A

  However, the existing interposer has a structure in which the terminals on both sides of the board are connected by a horizontal electric circuit and a vertical via that penetrates the board. To increase the pitch conversion rate, multiple boards are stacked. It was necessary to connect the terminals in a staircase pattern.

  For this reason, there is a problem that not only the structure of the interposer becomes complicated, but also the length of the electric circuit connecting the terminal of the IC and the terminal of the mounting substrate (or other IC) becomes long.

  This invention is made | formed in view of the said subject, Comprising: It aims at providing the interposer which can connect between terminals with the shortest electric circuit.

  An interposer according to the present invention includes a flat transparent insulator, a first electrode group that is a plurality of electrode groups disposed on a first surface of the transparent insulator, and the first electrode of the transparent insulator. A second electrode group which is the same number of electrode groups as the first electrode group disposed on the second surface which is the back surface of the first surface; and the first electrode group which penetrates the transparent insulator. And an electric circuit group connecting the corresponding electrodes of the second electrode group with the shortest distance.

  With this configuration, the terminals on both sides of the interposer can be linearly connected to simplify the structure.

  In the interposer according to the present invention, the electric circuit group is configured by an electric circuit formed on an inner wall of a through hole formed in the transparent insulator by femtosecond laser-assisted etching.

  With this configuration, a linear electric circuit can be formed in the transparent insulator.

  In the interposer according to the present invention, the electric circuit is formed in the through hole by plating or CVD.

  With this configuration, an electric circuit can be formed in the through hole having a high aspect ratio.

  The method of manufacturing an interposer according to the present invention includes a plurality of positions on the first surface of the flat transparent insulator and the second surface on the second surface which is the back surface of the first surface of the flat insulator. A modified portion forming step of forming a modified portion in the transparent insulator by a femtosecond laser along a shortest path with positions corresponding to a plurality of positions on one surface; and etching the modified portion by etching A drilling step of removing and drilling a through hole in the transparent insulator, an electric circuit forming step of forming an electric circuit inside the through hole, and the penetration of the first surface and the second surface of the flat insulator And an electrode group forming step of forming an electrode group electrically connected to the electric circuit at the opening position of the hole.

  According to the present invention, since the terminals on both sides of the interposer are linearly connected, the structure of the interposer can be simplified.

It is the top view (a), bottom view (c), and XX sectional view (b) of the interposer according to the present invention. It is a schematic diagram which shows the use condition of the interposer which concerns on this invention. It is a flowchart which shows the manufacturing method of the interposer which concerns on this invention. It is a schematic diagram in the case of forming a modified layer with femtosecond laser light. It is a block diagram of the ultra high-speed imaging device to which the backside illumination type image sensor and the interposer according to the present invention are applied.

  Examples of interposers according to the present invention will be described below.

  FIG. 1 is a top view (a), a bottom view (c), and an XX sectional view (b) of an interposer according to the present invention.

  The interposer 1 is a planar transparent insulator 11, and a first electrode group 12 is formed on the upper surface 11a, and a second electrode group 13 is formed on the lower surface 11b.

  The interelectrode pitch of the first electrode group 12 and the interelectrode pitch of the second electrode group 13 are different, and the number of electrodes constituting the first electrode group 12 and the second electrode group 13 are constituted. The number of electrodes is the same.

  The embodiment of FIG. 1 shows a case where the interelectrode pitch of the second electrode group 13 is twice the interelectrode pitch of the first electrode group 12, that is, the pitch conversion rate is “2”. This does not limit the present invention, and the pitch conversion rate may be any magnification (> 0) and need not be equal. Furthermore, the pitch between electrodes of each electrode group may not be the same.

  In the transparent insulator 11, an electric path group 14 that connects the corresponding electrodes of the first electrode group 12 and the second electrode group 13 with the shortest distance is provided.

  FIG. 2 is a schematic diagram showing the use situation of the interposer. The first IC 21 is mounted on the upper surface 11 a of the interposer 1, and the first electrode group 12 is in contact with the external terminal of the first IC 21. .

  A second IC (or printed circuit board) 22 is disposed under the lower surface 11 b of the interposer 1, and the second electrode group 13 is in contact with an external terminal of the second IC 22.

  Therefore, the external terminal of the first IC 21 and the external terminal of the second IC 22 are electrically connected via the first electrode group 12, the electric path group 14, and the second electrode group 13.

  FIG. 3 is a flowchart showing a method for manufacturing an interposer according to the present invention. First, as a first step, a modified portion is formed using a femtosecond laser on a transparent insulator 11 made of synthetic quartz, for example (step). 1).

  That is, when the femtosecond laser beam 31 is irradiated to a predetermined portion of the transparent insulator 11, the structural modification unit 32 is formed in the laser beam condensing unit.

  As the laser beam, a laser beam emitted from a titanium / sapphire laser having a wavelength of 800 nanometers, a pulse width of 260 to 300 femtoseconds, and a repetition frequency of 200 kilohertz is condensed with an objective lens having an aperture ratio of 0.5. is there.

  The energy of the laser pulse needs to be less than the ablation threshold of the transparent insulator so that the vicinity of the light condensing part is not damaged such as melting during the modification.

  By scanning the inside of the transparent insulator 11 with a laser at a speed of 1 millimeter per second, a modified portion having an arbitrary shape can be formed inside the transparent insulator 11.

  FIG. 4 is a schematic view when a modified layer is formed vertically upward from the central portion of the transparent insulator 11, and the laser is scanned from the central portion in the Z-axis direction.

  In addition, since it is desirable to form the modification from a position away from the surface of the transparent insulator 11 toward the surface, in order to form a through-hole penetrating from the upper surface 11a to the lower surface 11b of the transparent insulator 11, A reforming portion is formed from the central portion of the transparent insulator 11 to the upper surface 11a, the transparent insulator 11 is turned over, and a reforming portion is formed from the center portion to the lower surface 11b.

  Further, when forming a through hole that obliquely penetrates from the upper surface 11a to the lower surface 11b of the transparent insulator 11, the laser is scanned not only in the Z-axis direction but also in at least one of the X-axis and Y-axis directions. Good.

  Returning to FIG. 3, when the formation of the modified portion is completed, the modified portion is removed by etching, and a through hole is formed in the transparent insulating material 11 (step 2).

  Etching is preferably dry etching rather than wet etching from the viewpoint of maintaining the shape of the through hole.

  According to the above method, it is possible to form a high aspect ratio through-hole having a hole diameter of submicron and a length of several tens to several hundreds of microns.

  The above-described technique for forming a high aspect ratio through-hole by etching with a femtosecond laser is already known as a femtosecond laser-assisted etching method (for example, http://www.nedo.go.jp/content/ 100116677.pdf).

  Next, although an electric circuit is formed inside the through hole, it is practical to form a conductive layer on the inner wall of the through hole (step 3).

  As a method for forming the conductive layer, electrolytic plating, electroless plating, or CVD (chemical vapor deposition) can be applied.

  Finally, the first electrode group 12 and the second electrode group 13 connected to the electric path in the through hole are formed on the upper surface 11a and the lower surface 11b of the transparent insulator 11 (step 4), thereby completing the interposer.

  In the interposer according to the present invention, the electric circuit is formed so as to connect the upper electrode group and the lower electrode group at the shortest distance, but when applied to a circuit targeting a high frequency signal of gigahertz or more, There is also a demand to make the circuit lengths equal.

  According to the femtosecond laser assisted etching method described above, the modified portion can be formed three-dimensionally in the transparent insulator. Therefore, the present invention can be applied to the manufacture of an interposer having an equal circuit length. is there.

The interposer according to the present invention can be applied to an ultra high-speed imaging device using a backside illumination type imaging device and a semiconductor memory.
Conventionally proposed ultra-high-speed imaging devices mainly use a pixel peripheral recording type imaging device (In Situ Storage Image Sensor, hereinafter referred to as ISIS).

However, in the ISIS, since the photodiode and the storage element are formed on the same surface of the wafer, the actual light receiving area is reduced and the sensitivity is suppressed.
Therefore, in order to enable light reception over the entire wafer surface, a back-illuminated image sensor has been put into practical use.

The backside-illuminated image sensor has a structure in which an image sensor is formed on the entire back surface of the wafer, an image signal is transmitted to the wafer surface through an electric path penetrating the wafer, and the image sensor is output to the outside from an electrode formed on the wafer surface. It has become.
Therefore, the imaging signal output from the imaging device is continuously stored by bringing the surface of the back-illuminated imaging device into contact with the upper surface 11a of the interposer 1 according to the present invention and bringing the lower surface 11b into contact with the memory. Is possible.

  FIG. 5 is a configuration diagram of an ultra-high-speed imaging device to which the backside illumination type imaging device and the interposer according to the present invention are applied. FIG. 5D shows one backside illumination type imaging device 41 and one memory 42. (E) is a configuration in which one back-illuminated image sensor 41 and a plurality of memories 42, 43... Are connected by the interposer 1.

  INDUSTRIAL APPLICABILITY The present invention provides an interposer that can connect terminals with a shortest electric path, and is industrially useful.

1 Interposer 11 Transparent insulator 11a Upper surface (first surface)
11b Lower surface (second surface)
12 1st electrode group 13 2nd electrode group 14 Electric circuit group 21 1st IC
22 Second IC
31 Femtosecond laser beam 32 Structure modification unit 41 Back-illuminated image sensor 42, 43 Memory

Claims (4)

A flat transparent insulator;
A first electrode group that is a plurality of electrode groups disposed on the first surface of the transparent insulator;
A second electrode group which is the same number of electrode groups as the first electrode group disposed on a second surface which is the back surface of the first surface of the transparent insulator;
An interposer comprising an electric path group penetrating the transparent insulator and connecting the corresponding electrodes of the first electrode group and the second electrode group at a shortest distance.   2. The interposer according to claim 1, wherein the electric circuit group is configured by an electric circuit formed on an inner wall of a through hole formed in the transparent insulator by femtosecond laser-assisted etching.   The interposer according to claim 2, wherein the electric circuit is formed inside the through hole by plating or CVD. Corresponding to a plurality of positions on the first surface of the flat transparent insulator and a plurality of positions on the first surface on the second surface which is the back surface of the first surface of the flat insulator. A modified part forming step of forming a modified part in the transparent insulator by a femtosecond laser along the shortest path to the position to be
A drilling step of removing the modified portion by etching and drilling a through hole in the transparent insulator;
An electric circuit forming step of forming an electric circuit inside the through hole;
An interposer manufacturing method comprising: an electrode group forming step of forming an electrode group electrically connected to the electric path at the opening positions of the through holes on the first surface and the second surface of the flat insulator.

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