JP3466438B2 - Diffusion prevention method and diamond structure provided with diffusion prevention layer - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for preventing diffusion of a metallized layer and a brazing layer of a diamond device, and a diamond structure provided with the diffusion prevention layer. More specifically, in a diamond device in which a metallized layer and a brazing layer are provided on diamond, in order to prevent the metallized layer and the brazed layer from thermally diffusing each other when the diamond is heated from the outside. The present invention relates to a method of providing a diffusion prevention layer between a metallization layer and a brazing layer to prevent mutual diffusion, and a diamond structure provided with the diffusion prevention layer.

[0002]

2. Description of the Related Art Diamond having excellent thermal conductivity and insulating properties is used for heat sinks, sensors, ICs and the like used in semiconductor lasers. Then, a metallization layer is provided on the diamond surface to impart conductivity and to bond a semiconductor laser or the like. Although this metallized layer can be used as it is as an adhesive layer, a brazing layer is further provided as an upper layer of the metallized layer in order to facilitate heat adhesion at a low temperature.

As an example, in a diamond heat sink used as a heat sink for a semiconductor laser, three layers of Ti, Pt, and Au are formed as metallized layers, and then Au—Sn alloy layers are sputtered as brazing layers. Formed using the method. The diamond heat sink having the metallized layer and the brazing layer thus formed is mounted on the semiconductor laser by heating and melting the brazing layer as an adhesive layer. But,
When the brazing layer and the metallized layer are mutually thermally diffused when the brazing layer is heated and melted, the composition of the alloy forming the brazing layer changes, and the melting point shifts to the high temperature side.
The liquid phase necessary for fusing may not be generated and a sufficient adhesive effect may not be obtained.

[0004]

A technical problem to be solved by the present invention is to prevent a metallized layer and a brazing layer formed on a diamond from mutually thermally diffusing, and a metallized layer and a brazing layer. The object is to provide a diamond structure which prevents mutual thermal diffusion of the layers.

[0005]

A method for preventing diffusion of a diamond structure according to claim 1, wherein a metallized layer is provided on the surface of the diamond by using a magnetron sputtering method.
In a method of preventing diffusion of a diamond structure, further comprising a brazing layer as an upper layer thereof, a magnetron sputtering method is used between the metallization layer and the brazing layer to obtain Ni of 300 to 500 nm and Ni of 100 to 500 nm. Cr, 25-500 nm Zr, 25-500 nm M
or a single layer of W having a thickness of 25 to 500 nm, or a multi-layer thereof, to form a diffusion prevention layer for preventing the metallized layer and the brazing layer from thermally diffusing each other. A brazing layer is formed on the diffusion preventing layer. A method for preventing diffusion of a diamond structure according to claim 2 is the method according to claim 1, wherein the metallized layer is formed of Ti, Pt, and A sequentially from the diamond side.
u. The diamond structure according to claim 3, wherein a metallized layer formed by using a magnetron sputtering method is provided on the surface of the diamond, and a brazing layer is further provided on the metallized layer. 300-500 nm Ni, 100-500 nm Cr, 25-500 nm Zr, 25-500 nm M formed using a magnetron sputtering method between the layer and the brazing layer.
o, or a single layer of W of 25 to 500 nm, or a multi-layer of these is formed to be a diffusion prevention layer for preventing the metallized layer and the brazing layer from thermally diffusing each other, A brazing layer is formed on the diffusion preventing layer. A fourth aspect of the present invention is the diamond structure according to the third aspect, wherein the metallized layer is Ti, Pt, and Au in order from the diamond side. A diamond structure according to a fifth aspect is the diamond structure according to the third or fourth aspect, wherein the diamond structure is a diamond heat sink.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors provide a metallized layer by providing a heat diffusion preventing layer between a metallized layer and a brazing layer in a diamond structure obtained by providing a metallized layer and a brazing layer on diamond. It is possible to prevent mutual heat diffusion between the metallized layer and the brazing layer when heat-sealing the diamond structure provided with the layer and the brazing layer to another device, and the diamond structure and the other device. It has been found that excellent adhesive strength can be obtained.

The present invention will be described in detail below on the assumption that a diamond heat sink as a diamond structure is mounted on a semiconductor laser as an element. First, the diamond coating the protective film of the present invention will be described. In the present invention, the diamond material may be synthetic diamond, high-pressure synthetic diamond, or natural diamond, and may have a single crystal structure or a polycrystal structure. However, from the viewpoint of productivity, microwave plasma C
It is preferable to use diamond manufactured by a vapor phase synthesis method such as the VD method.

The upper and lower surfaces of these diamonds are polished,
Then, after hydrogen plasma cleaning or oxygen plasma cleaning is performed, a metallized layer is formed by using a DC magnetron sputtering method or an RF magnetron sputtering method. W, Ti, Mo, Ni, Cr, P
It is preferable that at least one of t, Pd, Au, Ag, and Cu is a single-layer film, an alloy film, or a composite film of one or more layers, which chemically reacts with diamond to improve adhesive strength and heat resistance. It is necessary to have it.

On one of the upper and lower surfaces on which the above metallized layer is formed, a heat diffusion preventing element composed of an element constituting the metallized layer, an element constituting an upper brazing layer, and an element difficult to thermally diffuse Provide layers. As such an element, which is relatively inexpensive and easily applicable, Ni,
Examples thereof include Cr, Zr, Mo and W. The thermal diffusion preventing layer made of these elements is formed on the metallized layer by using the DC magnetron sputtering method or the RF magnetron sputtering method. The heat diffusion preventing layer may be a single layer made of one of the above-mentioned elements,
It may be a multilayer composed of two or more kinds.

On the metallized layer and the heat diffusion preventing layer thus formed, an adhesive layer which can be brazed at a low temperature to a semiconductor laser chip which is easily broken at a high temperature is formed on the metallized layer and the heat diffusion preventing layer. Such a brazing layer may be, for example, an Au—Sn alloy layer formed by using a DC magnetron sputtering method or an RF magnetron sputtering method, or a solder layer formed by either a wet plating method or a sputtering method. preferable.

The diamond heat sink on which the metallized layer, the heat diffusion preventing layer and the brazing layer are formed as described above is heated to a temperature equal to or higher than the melting point of the brazing layer, and the semiconductor laser chip is thermally fused thereto.

[0012]

EXAMPLES The present invention will be described more specifically below with reference to examples. [Creation of Diamond] A diamond having a thickness of 0.35 mm, a length of 25 mm, and a width of 25 mm was prepared by using the microwave CVD method. Polish the top and bottom of this diamond,
The thickness is 0.25 mm.

[Formation of Metallized Layer] After polishing polished diamond with hydrogen plasma, Ti, Pt, and
Each layer was formed in the order of Au. The thickness of each layer is Ti: 10
0 nm, Pt: 100 nm, Au: 500 nm.

[Formation of Diffusion-Preventing Layer] Various diffusion-preventing layers were formed on both sides of the diamond on which the metallized layer was formed as described above, using the DC magnetron sputtering method under the conditions shown in Tables 1 and 2. .

[Formation of Brazing Layer] Further on the metallization layer and the diffusion prevention layer formed as described above,
A brazing layer was formed. That is, an Au—Sn alloy layer (Au / Sn = 80% by weight / 20% by weight) was formed with a thickness of 2.8 μm on one surface of the diamond on which the diffusion prevention layer was formed, by using the DC magnetron sputtering method. . The diamond structure (heat sink) was obtained as described above.

[Divided Cutting] The diamond structure having various heat diffusion preventing layers formed as described above was divided and cut using a laser.

[Heat Fusion to Semiconductor Chip] The semiconductor chip is placed on the diamond structure divided and cut as described above, and heated in a high-purity argon to a temperature not lower than the melting temperature of the brazing layer, and the semiconductor chip is fixed. It was heat-sealed onto the diamond structure. This heat fusion work was observed with a microscope of 600 times, and the heat fusion state was evaluated according to the following evaluation criteria. ◯: Good (it is observed that the brazing layer melts and a sufficient liquid phase appears) Δ: Somewhat poor (the brazing layer melts, but the liquid phase appears poor) ×: Poor (brazing No melting was observed and no liquid phase appeared.) The results are shown in Tables 1 and 2.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

INDUSTRIAL APPLICABILITY According to the present invention, in a diamond structure in which a metallized layer and a brazing layer are provided on diamond, a heat diffusion preventing layer is provided between the metallized layer and the brazed layer, and the metallized layer and the brazed layer are When heat-bonding the diamond structure provided to another element, a method for preventing the metallization layer and the brazing layer from mutually thermally diffusing, and between the metallization layer and the brazing layer, a metallization layer and A diamond structure provided with a diffusion preventing layer for preventing the brazing layers from thermally diffusing each other, and by using the method of the present invention, the brazing layer when the brazing layer is heated and melted. The mutual heat diffusion between the metallized layer and the metallized layer is prevented, the composition of the alloy forming the brazing layer does not change, the liquid phase required for fusion is generated, and a sufficient adhesive effect is obtained.

Continuation of front page (56) Reference JP-A-60-155600 (JP, A) JP-A-6-236855 (JP, A) JP-A-57-86146 (JP, A) JP-A-61-183200 (JP , A) JP 2-15682 (JP, A) JP 5-92307 (JP, A) JP 5-237708 (JP, A) JP 6-275554 (JP, A) JP 11-49595 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C30B 1/00-35/00 H01L 21/28

Claims (5)

(57) [Claims] 1. A magnetron spat on a diamond surface.
In the method for preventing the diffusion of a diamond structure, which comprises providing a metallization layer by using a metallization method, and further providing a brazing layer on the metallization layer, a magnet is provided between the metallization layer and the brazing layer.
Using the Ron sputtering method, 300 to 500 nm of Ni, 100 to 500 nm of C
r, 25-500 nm Zr, 25-500 nm M
o, or a single layer of W of 25 to 500 nm, or by forming these multilayer, and the brazing layer and the metallization layer and the diffusion preventing layer for preventing the thermal diffusion into one another, then A method for preventing diffusion of a diamond structure, comprising forming a brazing layer on the diffusion prevention layer . 2. The metallized layer is from the diamond side.
Sequentially comprising Ti, Pt, and Au ,
The method for preventing diffusion of a diamond structure according to claim 1. 3. A diamond structure, wherein a metallized layer formed by a magnetron sputtering method is provided on a diamond surface, and a brazing layer is further provided on the metallized layer, wherein the metallized layer and the brazed layer are provided. Between 300 and 500 n formed by using a magnetron sputtering method between
m Ni, 100-500 nm Cr, 25-500 n
m Zr, 25-500 nm Mo, or 25-500
a single layer of W of nm or a multi-layer of these layers is formed to serve as a diffusion prevention layer for preventing the metallized layer and the brazing layer from thermally diffusing each other. A diamond structure characterized in that a brazing layer is formed on the diamond structure. 4. The metallized layer comprises Ti, Pt, and Au in this order from the diamond side.
The diamond structure according to claim 3. 5. The diamond structure according to claim 3, wherein the diamond structure is a diamond heat sink.
The diamond structure according to.