JP2019079965A - Columnar conductor structure - Google Patents

Abstract

To provide a columnar conductor structure with excellent shielding properties, conductivity, and heat resistance.SOLUTION: A columnar conductor structure A in which a conductor is filled in a through hole 102 provided in the thickness direction of a substrate 100 includes a first layer 103 in contact with the wall surface or the bottom surface of the through hole 102, a second layer 104 provided on the surface, and a filling layer 105 filling the through hole 102 inside the second layer 104, and the first layer 103 is a metal layer with a thickness of 0.1 μm to 10 μm, the second layer 104 is constituted by a layer including a first intermetallic compound with a thickness of 1 μm to 10 μm, and the filling layer 105 is constituted by a second intermetallic compound 1051 and an alloy 1052, and the second intermetallic compound 1051 occupies at least 5% by mass of the filling layer 105, and the second intermetallic compound 1051 is dispersed in the alloy 1052.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a columnar conductor structure.

  For example, in a semiconductor device, a method of planarly arranging a semiconductor chip on a substrate and connecting the wiring with each other has been employed. However, with this method, the mounting area increases with the number of semiconductor chips, and the wiring length also increases. Therefore, it is difficult to realize small-sized, large-capacity, high-performance, and low-power consumption semiconductor devices. is there. At present, as miniaturization technology has advanced to the limit, achieving higher capacity, higher performance and lower power consumption has come to the limit through miniaturization and miniaturization of semiconductor chips.

  Therefore, development of semiconductor devices in a three-dimensional arrangement according to a so-called TGV (Through Glass Via) method in which semiconductor chips are stacked and chips are connected by through electrodes has been advanced. With TGV technology, a large amount of functions can be packed into a small footprint, and important electrical paths between elements can be dramatically shortened, leading to faster processing.

  A representative technology for realizing a three-dimensional semiconductor device according to the TGV method is a plating method of forming a through electrode by applying a plating technology, and a vacuum chamber in which a silicon substrate having a minute space is depressurized to a vacuum pressure. After the silicon substrate is inserted into the molten metal bath and the silicon substrate reaches almost the same temperature as the molten metal, the inside of the vacuum chamber is pressurized, for example, over atmospheric pressure to fill the molten metal in the fine space and harden it. It is a molten metal filling method which forms the penetration conductor which consists of a solidification conductor.

  However, it is extremely difficult to sufficiently fill the filler to the bottom of the fine space having a high aspect ratio without causing voids or deformation after curing. As prior art that can overcome such technical difficulties, the filling methods and devices described in Patent Documents 1 and 2 are known.

  The technique described in Patent Document 1 is a method of filling and curing a molten metal in a minute space existing in a wafer, and applying a forced external force exceeding atmospheric pressure to the molten metal in the minute space. Cooling and hardening the molten metal. The forcible external force is given by at least one selected from a press pressure, an injection pressure, and a compaction pressure, and the molten metal is viewed from the open surface side where the fine space opens in a state where the other end side of the fine space is closed. Applied to the Patent Document 2 discloses an apparatus for performing the method described in Patent Document 1.

  According to the techniques described in Patent Documents 1 and 2 described above, the fine space can be filled with the filler without causing voids or voids in the conductor structure in the fine space, and the hardened metal cooled by the fine space It is possible to obtain excellent operational effects such as the ability to avoid the formation of a concave surface and to contribute to the simplification of the process, the improvement of the yield and the like.

  The inventions disclosed in Patent Documents 1 and 2 are extremely useful techniques for the practical application of TGV (through Glass via) technology, but for the application of recent power semiconductors, etc., the shieldability of the conductor structure, the conductivity, etc. And heat resistance improvement is required.

  In addition, Patent Document 3 describes a method of forming a silicon through wiring (TSV) in a through hole of a silicon board in a three-dimensional integration technique, and a space inside a through hole of a small diameter prepared in the silicon board. Discloses a technique for filling with molten solder. Specifically, a manufacturing method is disclosed in which the Sn powder is heated and melted after the Cu powder is introduced into the through holes. However, in the technique disclosed in Patent Document 3, Cu and Sn react at the entrance of the through hole, an intermetallic compound is instantaneously generated, and a conductor structure can not be formed inside the through hole. was there.

Patent 4278007 gazette Patent No. 4505540 Patent No. 6021125

  An object of the present invention is to provide a columnar conductor structure excellent in shieldability, conductivity and heat resistance.

As a result of intensive studies, the present inventor has found that the above problems can be solved by specifying the fine structure of the packed bed filling the inside of the bottomed hole or the through hole.
That is, the present invention is as follows.

1. A columnar conductor structure in which a conductor is filled in a bottomed hole or a through hole provided in a thickness direction of a substrate,
The columnar conductor structure includes a first layer in contact with a wall surface or a bottom surface of the bottomed hole or the through hole, a second layer provided on a surface of the first layer, and the bottomed layer inside the second layer. And a filling layer filling the holes or the through holes;
The first layer is a metal layer having a thickness of 0.1 μm to 10 μm,
The second layer consists of a layer containing a first intermetallic compound with a thickness of 1 μm to 10 μm,
The packed bed comprises a second intermetallic compound and an alloy,
The second intermetallic compound accounts for at least 5% by mass in the packed bed, and the second intermetallic compound is dispersed in the alloy.
Columnar conductor structure.
2. The columnar conductor structure described in 1 above,
The first layer contains a metal capable of forming an intermetallic compound with Sn,
The first intermetallic compound in the second layer comprises an intermetallic compound of Sn and the metal of the first layer,
The filler layer comprises Sn or Sn alloy
Columnar conductor structure.
3. The columnar conductor structure described in 1 or 2 above,
The substrate is an insulating substrate,
Columnar conductor structure.
4. The columnar conductor structure described in 1 or 2 above,
The substrate is a semiconductor substrate,
An insulating layer is present between the first layer and the wall surface or bottom surface of the bottomed hole or the through hole.
Columnar conductor structure.
5. The semiconductor device which has a columnar conductor structure in any one of said 1-4.

  The columnar conductor structure of the present invention comprises a first layer in contact with a wall surface or a bottom surface of a bottomed hole or a through hole provided in a thickness direction of a substrate, a second layer provided on the surface of the first layer, And a filling layer filling the bottomed holes or the through holes inside the two layers, defining the thickness of the first layer and the second layer within a specific range, and forming the filling layer with an intermetallic compound And the alloy phase, and the amount and form of the intermetallic compound are specified, so that it is possible to provide a columnar conductor structure excellent in shieldability, conductivity and heat resistance.

It is a schematic sectional drawing for demonstrating the columnar-conductor structure of this invention. It is a figure for demonstrating an example of a manufacturing apparatus suitable for manufacture of the metal particle of this invention. It is a cross-sectional STEM-EDS Mapping SEM image of the metal particle of this invention obtained in the Example. It is a SEM image of the cross section of the columnar conductor structure of this invention created in the Example. It is a SEM image of the cross section of the columnar conductor structure created in the reference example 1. It is a SEM image of the cross section of the columnar conductor structure created in the reference example 2.

Hereinafter, the present invention will be further described with reference to the drawings, but the present invention is not limited to the following examples.
FIG. 1 is a schematic cross-sectional view for explaining a columnar conductor structure of the present invention.

  In FIG. 1, a columnar conductor structure A according to the present invention has a structure in which a conductor is filled in, for example, a bottomed hole or a through hole 102 provided in the thickness direction of the insulating substrate 100 (FIG. 1 shows the through hole) Yes). The hole diameter of the through hole 102 is, for example, 80 μm or less, specifically about 20 μm to 60 μm, and the depth is a value such that the aspect ratio with the hole diameter is 1 or more, preferably 5 or more. When the substrate 100 is, for example, a glass substrate, a large number of through holes 12 are provided in the glass surface.

  The columnar conductor structure A fills the through hole 102 inside the second layer 104 and the first layer 103 in contact with the wall surface or the bottom surface of the through hole 102, the second layer 104 provided on the surface of the first layer 103. And a packed bed 105.

  The first layer 103 is a metal layer with a thickness of 0.1 μm to 10 μm, and is preferably a layer composed of, for example, Sn and a metal capable of forming an intermetallic compound. Cu is preferable as the metal. The first layer can be provided with Cu, for example, on the surface of the through hole 12 using a method such as plating or sputtering.

  The second layer 104 may be a layer including a first intermetallic compound having a thickness of 1 μm to 10 μm, and the first intermetallic compound may include a low melting point metal and a high melting point metal, for example, Ag, Cu , Au, Pt, Ti, Zn, Al, Fe, Si and Ni can be made of a material selected from the group consisting of

The filling layer 105 is composed of a second intermetallic compound 1051 and an alloy 1052. The second intermetallic compound 1051 may include a low melting point metal and a high melting point metal, and is selected from, for example, the group of Ag, Cu, Au, Pt, Ti, Zn, Al, Fe, Si and Ni. It can be configured by the material. The second intermetallic compound 1051 occupies at least 5% by mass in the packed bed 105, and the second intermetallic compound 1051 is dispersed in the alloy 1052. Further, according to a preferred embodiment of the present invention, at least a part of the second intermetallic compound 1051 is bonded to the second layer 104, and the second intermetallic compounds 1051A are bonded to each other, and the through holes 102 of the filling layer 105 are formed. The skeletal structure is configured to cross between them. According to such a structure, the conductivity and heat resistance of the columnar conductor structure A can be further enhanced.
In addition, the second intermetallic compound 1051 can suppress volume contraction during cooling, grain growth of a conductor, and crystal growth. Therefore, the occurrence of micro cracks in the columnar conductor structure A can be suppressed.

  The alloy 1052 of the filling layer 105 may be made of a low melting point metal or an alloy, and contributes to the shieldability of the columnar conductor structure A.

  The columnar conductor structure A of the present invention as described above can be formed using the metal particles described below (hereinafter sometimes referred to as the metal particles of the present invention). In addition, although the metal particle of this invention demonstrated below consists of Sn and Cu, this invention is not restrict | limited to this form. The second layer 104 and the filling layer 105 can contain a low melting point metal and a high melting point metal, and are selected from, for example, the group of Ag, Cu, Au, Pt, Ti, Zn, Al, Fe, Si and Ni. It is as mentioned above that it can consist of the material which has been.

  The metal particle of the present invention can be produced, for example, from a raw material (hereinafter referred to as 8Cu · 92Sn) in which 8% by mass Cu and 92% by mass Sn are combined. For example, 8Cu · 92Sn is melted and supplied onto a dish-shaped disk rotating at high speed in a nitrogen gas atmosphere, the molten metal is scattered as small droplets by centrifugal force, and solidified by cooling under reduced pressure. The metal particle of the invention can be obtained. In the above embodiment, the metal particles of the present invention do not exclude the inclusion of elements other than Cu and Sn.

  An example of a production apparatus suitable for producing the metal particles of the present invention will be described with reference to FIG. The granulation chamber 1 has a cylindrical upper portion and a conical lower portion, and a lid 2 at the upper portion. A nozzle 3 is vertically inserted at the center of the lid 2, and a dish-shaped rotating disk 4 is provided immediately below the nozzle 3. The code | symbol 5 is a mechanism which supports the dish-shaped rotary disc 4 so that a movement is possible up and down. Further, at the lower end of the cone portion of the granulation chamber 1, a discharge pipe 6 of the generated particles is connected. The upper part of the nozzle 3 is connected to an electric furnace (high frequency furnace) 7 for melting the metal to be granulated. The atmosphere gas adjusted to a predetermined component by the mixed gas tank 8 is supplied to the inside of the granulation chamber 1 and the upper portion of the electric furnace 7 by the pipes 9 and 10, respectively. The pressure in the granulation chamber 1 is controlled by the valve 11 and the exhaust device 12, and the pressure in the electric furnace 7 is controlled by the valve 13 and the exhaust device 14, respectively. The molten metal supplied from the nozzle 3 onto the disc-shaped rotating disc 4 is finely dispersed by the centrifugal force of the disc-shaped rotating disc 4 and scattered, and is cooled under reduced pressure to become solid particles. The generated solid particles are supplied from the discharge pipe 6 to the automatic filter 15 and separated. Reference numeral 16 is a particle collection device.

The process of cooling and solidifying the molten metal under reduced pressure is important to form the crystal structure of the metal particles of the present invention.
For example, the following conditions may be mentioned.
Dish-shaped rotating disk 4: Using a disk-shaped disk with an inner diameter of 60 mm and a depth of 3 mm, it is 80,000 to 100,000 rotations per minute.
Granulation chamber 1 After reducing the pressure using a vacuum tank having the ability to reduce the pressure to about 9 × 10 ^-2 Pa and simultaneously discharging nitrogen gas at 15 to 50 ° C., the granulation chamber 1 is carried out. The internal pressure is set to 1 × 10 ⁻¹ Pa or less.
The particle size of the metal particles produced under these conditions is, for example, 20 μm or less in diameter, and typically 2 μm to 15 μm.

  The produced metal particles of the present invention can also be processed into a sheet or paste. The sheet made of the metal particles of the present invention can be obtained, for example, by supplying the metal particles between a pair of pressure rollers rotating in opposite directions and heated, and pressing them. Further, a paste comprising the metal particles of the present invention can be obtained by mixing the metal particles of the present invention in an organic vehicle. In addition, other particles such as SnAgCu-based alloy particles and / or Cu particles may be added to the sheet or the conductive paste as long as the effects of the present invention are not impaired, and they may be mixed with metal particles. These other particles may optionally be coated with a metal such as Si.

  The form which produces columnar-conductor structure A of this invention using the metal particle of this invention manufactured as mentioned above is demonstrated. The columnar conductor structure A of the present invention can be manufactured, for example, according to the method described in Japanese Patent No. 5450780.

First, for example, Cu is provided on the surface of the through hole 102 of the insulating substrate 100 using a known method such as plating or sputtering so as to have a thickness of 0.1 μm to 10 μm.
Subsequently, the metal particles of the present invention are placed on the through holes 102 and pressurized under heat in a reducing atmosphere at 230 ° C. to 280 ° C. to be cured. In such a process, the metal particles of the present invention are melted by heating, enter the through holes 102, react with the first layer Cu, and contain a first intermetallic compound (for example, containing Cu ₃ Sn). A second layer is formed with a thickness in the range of 1 μm to 10 μm. At the same time, the filler layer 105 is formed with the same structure as that of the metal particles of the present invention. The metal particle of the present invention is a particle composed of an intermetallic compound crystal containing Sn and Cu (for example, containing Cu ₆ Sn ₅ ) is a crystal in which a nano-sized intermetallic compound in a Sn alloy is contained. At the time of formation of the metal particles, an intermetallic compound is precipitated in the Sn alloy, and the precipitated intermetallic compound is filled with the melted alloy into the through holes without being melted, and the heat resistance of the columnar conductor structure A of the present invention It can be further enhanced.

  As a reducing agent for forming a reducing atmosphere, preferably, a vapor of a carboxylic acid (R-COOH, R is a monovalent functional group) can be used. Examples of carboxylic acids include formic acid, acetic acid, acrylic acid, propionic acid, butyric acid, caproic acid, oxalic acid, succinic acid, salicylic acid, malic acid, enanthate, caprylic acid, pelargonic acid, lactic acid, capric acid and the like. One or more may be selected and mixed. Of these carboxylic acids, formic acid is suitable. Since the reducing action by the carboxylic acid generally becomes significant at a temperature above its boiling point, for example, at a temperature of 200 ° C. or more, the reducing atmosphere preferably satisfies this temperature range.

  Moreover, when heating the metal particle of this invention, it is preferable to make the inside of a chamber into a pressure-reduced atmosphere. After pressure reduction processing, a differential pressure filling method may be employed in which the internal pressure of the chamber is increased. By such means, the metal particles of the present invention can be reliably filled in the through holes 102. Further, at the time of heating, when the insulating substrate 100 is vibrated by ultrasonic waves or the like, the filling operation can be smoothly performed.

  In the above description, the insulating substrate 100 has been described as an example of the substrate, but the substrate used in the present invention may be a wafer, a circuit substrate, a laminated substrate, a semiconductor substrate, MEMS (Micro-Electro-Mechanical Systems), etc. Those having 102 are widely included. Specifically, it is a through hole represented by TGV (Through Glas Via), a non-through hole (blind hole) or the like. In particular, a semiconductor substrate is preferable as the substrate in the present invention, and a form in which an insulating layer is present between the wall surface or bottom surface of the bottomed hole or through hole and the first layer is mentioned as the columnar conductor structure of the present invention. Thus, the columnar conductor structure of the present invention is useful as a semiconductor device.

  Hereinafter, the present invention will be further described by way of examples and comparative examples, but the present invention is not limited to the following examples.

Example 1
Using 8 Cu · 92 Sn as a raw material, metal particles having a diameter of about 3 to 13 μm were produced by the production apparatus shown in FIG.
At that time, the following conditions were adopted.
Dish-shaped rotating disk 4: A disk-shaped disk with an inner diameter of 60 mm and a depth of 3 mm was used at 80,000 to 100,000 rotations per minute.
Granulation chamber 1 After reducing the pressure using a vacuum tank having the ability to reduce the pressure to about 9 × 10 ^-2 Pa and simultaneously discharging nitrogen gas at 15 to 50 ° C., the granulation chamber 1 is carried out. The internal pressure was less than 1 × 10 ⁻¹ Pa.

  FIG. 3 is a cross-sectional STEM-EDS Mapping SEM image of the metal particle of the present invention obtained in the example. It is observed from FIG. 3 that the metal particles of the present invention contain intermetallic compound crystals and a Sn alloy.

Subsequently, using the obtained metal particles of the present invention, a columnar conductor structure of the present invention as shown in FIG. 1 was formed.
First, Cu was plated on the surface of the through hole 102 of the insulating substrate 100 by a plating method. Thus, a first layer 103 made of Cu and having a thickness of about 2 μm was formed. The inner diameter of the through hole 102 is about 20 to 60 μm.
Subsequently, the insulating substrate 100 on which the first layer 103 is formed is introduced into a vacuum chamber, and the metal particles of the present invention are placed on the through holes 102, and at 250 ° C to 280 ° C in a reducing atmosphere of formic acid. Then, the metal particles of the present invention were pressurized at 2 to 8 MPa, and the metal particles of the present invention were filled in the through holes 102 and cured to form the second layer 104 and the filling layer 105.

FIG. 4 is a SEM image of the cross section of the columnar conductor structure of the present invention prepared in the example.
It was observed from FIG. 4 that the second layer 104 containing the first intermetallic compound (including Cu ₃ Sn) was formed with a thickness of 1.5 μm. The second layer 104 is formed by the reaction of the molten metal particle of the present invention and Cu as the first layer 103. In addition, the filling layer 105 is made of a second intermetallic compound 1051 (an intermetallic compound crystal containing Sn and Cu containing Cu ₆ Sn ₅ ) dispersed in a Sn alloy, and the filling layer 105 is a dispersed intermetallic compound. It was found that it was composed of an alloy phase. In the columnar conductor structure, defects such as micro cracks were not observed, and high shieldability by the intermetallic compound was revealed.

  In order to confirm the heat resistance of the columnar conductor structure of the present invention prepared above, it was possible to confirm by image that there is no change in the melt expansion in the shape change after being left at 300 ° C. for 10 minutes. As a result, high heat resistance of the columnar conductor structure of the present invention was confirmed.

Reference Example 1
In Example 1, after introducing Cu powder into the through holes 102 without using the metal particles of the present invention, Sn powder is heated and melted, and the above heating step and pressing step are performed, Example 1 was repeated.
FIG. 5 is an SEM image of the cross section of the columnar conductor structure produced in the first reference example.
From the results in FIG. 5, in the reference example 1, Cu and Sn react at the entrance of the through hole, an intermetallic compound is instantaneously generated, only Cu powder remains in the through hole, and the conductor is inside the through hole It was not possible to form a structure.

Reference Example 2
Example 1 was repeated except that the metal particle of the present invention was not used in Example 1 and a commercially available SnAgCu-based bonding material (SAC) was used. However, when trying to investigate the heat resistance of the columnar conductor structure, as shown in FIG. 6B, the SAC melts and spouts, and as shown in FIG. 6A, the through holes become almost voided after the SAC spouts. It was not possible to conduct a sex test.

  Although the present invention has been described in detail with reference to the accompanying drawings, the present invention is not limited thereto, and various modifications may be made by those skilled in the art based on the basic technical concept and teaching thereof. It is self-evident that it can be conceived.

DESCRIPTION OF SYMBOLS 1 granulation chamber 2 lid 3 nozzle 4 dish-shaped rotating disk 5 rotating disk support mechanism 6 particle discharge pipe 7 electric furnace 8 mixed gas tank 9 piping 10 piping 11 valve 12 exhausting device 13 valve 14 exhausting device 15 automatic filter 16 particulate collection device 100 Insulating Substrate 102 Through Hole 103 First Layer 104 Second Layer 105 Filled Layer 1051 Second Intermetallic Compound 1052 Alloy A Columnar Conductor Structure

Claims (5)

A columnar conductor structure in which a conductor is filled in a bottomed hole or a through hole provided in a thickness direction of a substrate,
The columnar conductor structure includes a first layer in contact with a wall surface or a bottom surface of the bottomed hole or the through hole, a second layer provided on a surface of the first layer, and the bottomed layer inside the second layer. And a filling layer filling the holes or the through holes;
The first layer is a metal layer having a thickness of 0.1 μm to 10 μm,
The second layer consists of a layer containing a first intermetallic compound with a thickness of 1 μm to 10 μm,
The packed bed comprises a second intermetallic compound and an alloy,
The second intermetallic compound accounts for at least 5% by mass in the packed bed, and the second intermetallic compound is dispersed in the alloy.
Columnar conductor structure. A columnar conductor structure according to claim 1, wherein
The first layer contains a metal capable of forming an intermetallic compound with Sn,
The first intermetallic compound in the second layer comprises an intermetallic compound of Sn and the metal of the first layer,
The filler layer comprises Sn or Sn alloy
Columnar conductor structure. A columnar conductor structure according to claim 1 or 2, wherein
The substrate is an insulating substrate,
Columnar conductor structure. A columnar conductor structure according to claim 1 or 2, wherein
The substrate is a semiconductor substrate,
An insulating layer is present between the first layer and the wall surface or bottom surface of the bottomed hole or the through hole.
Columnar conductor structure.   The semiconductor device which has a columnar conductor structure in any one of Claims 1-4.