JP3528375B2 - Substrate and heat dissipation substrate using the same, semiconductor device, element mounting device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate, a heat dissipation substrate using the same, a semiconductor device, and an element mounting device.
The substrate of the present invention is suitable for mounting and cooling an element having a large heat generation density such as a semiconductor element such as an ultra high speed MPU or a high power semiconductor laser. The elements may be those requiring strict temperature control, and may be arranged in high density.

[0002]

2. Description of the Related Art Semiconductor lasers used for submarine cables and the like have been increased in output in order to realize long-distance transmission, and the amount of heat generated by the element itself has been rapidly increasing accordingly.
Further, with the downsizing of information processing systems and the increase in processing speed, the processing capability per unit area of semiconductor elements incorporated in these devices is rapidly improving. These things lead to an increase in the amount of heat generated per unit area of the semiconductor element, and the importance of ensuring the heat dissipation of the mounted substrate has attracted attention. Further, in these elements, it is necessary to strictly control the operating temperature, and a change in element temperature causes, for example, a shift in oscillation wavelength.

[0003]

With materials such as alumina which are mainly used in packages at present, the heat dissipation characteristics thereof become a problem when the above high performance elements are mounted. That is, in the current package, the inherent thermal resistance is large, the heat generated by the device itself cannot be sufficiently dissipated, and the device temperature rises. As a result, the device may malfunction or run away. In order to solve this problem, it is effective to use a material having higher thermal conductivity as described above, and diamond having the highest thermal conductivity among existing substances is also used in semiconductor laser diodes and the like.

However, the heat transported by the heat dissipation board must be finally transferred to the outside air or cooling water to be discharged. If the amount of heat generated by the mounted semiconductor element increases, it is of course necessary to use a high thermal conductivity material, and how to efficiently dissipate the large amount of heat that has conducted through the high thermal conductivity material from the substrate. Becomes important. Therefore, a fin and a cooling water pipe are attached to the back surface of the substrate to increase the heat radiation area and heat radiation efficiency. However, if the cooling water pipe is attached to the back side of the board, it is not possible to prevent extra heat resistance from entering that attachment part, and the fins will have a lower cooling efficiency, and thus have high heat dissipation that enables more efficient cooling. Substrate development is required.

Recent improvements in the processing speed of semiconductor devices, particularly LSIs, and progress in packaging technology for portable information processing equipment such as laptop personal computers are remarkable. LS
The improvement in the processing speed of I made the signal delay due to the wiring connecting between the chips not negligible. Further, the need for portable information processing equipment has brought about a sharp increase in the packaging density of the LSI.

A mounting board satisfying these requirements has been required to meet the contradictory requirements of improving substantially the mounting density of each semiconductor element and efficiently removing the generated heat. Therefore, MCM (Multi Chip Module)
High-density mounting technology including boards has been developed and is now being used mainly in CPUs of supercomputers.

With respect to the MCM substrate, the AlN substrate is currently used as the substrate that requires the most heat dissipation characteristics. However, AlN has a thermal conductivity of about 2 W / cm · K, and it is becoming difficult to cope with it in order to mount high-density mounting and high heat-density elements in the future.

Japanese Unexamined Patent Publication No. 4-273466 proposes a structure in which a coolant is allowed to flow in a side surface of a three-dimensional integrated circuit board using diamond.
However, in this structure, the vicinity of the center of the substrate (the part where the temperature is expected to rise most) is farthest from the place where the refrigerant passes, and the efficiency is poor.

[0009]

In view of the above problems, the inventors of the present invention have conducted diligent research to obtain a heat dissipation board having a higher cooling efficiency, and pass the refrigerant directly through the high thermal conductivity material. We have succeeded in obtaining a substrate with significantly improved heat dissipation efficiency by forming the flow path of.

According to the present invention, a high thermal conductive material layer having a thermal conductivity of 10 W / cm · K or more is disposed on a base material, and the high thermal conductive material layer at the interface between the base material / high thermal conductive material layer. Provided is a substrate (for example, a heat dissipation substrate) having a channel for passing a cooling medium on its side. Further, the present invention provides a high thermal conductive substance layer having a thermal conductivity of 10 W / cm · K or more on a substrate, and the high thermal conductive substance layer side of the interface portion of the substrate / high thermal conductive substance layer. An element mounting apparatus, characterized in that a heating element having a maximum heat generation density of 1 W / cm ² or more is mounted on the high thermal conductive material layer, the heating element having a flow path for passing a cooling medium. This element mounting device comprises a substrate formed of a base material and a high thermal conductive material layer, and an element mounted on the substrate.

In addition, the present invention has a thermal conductivity of 10 W / cm.
Provide a substrate (for example, a heat dissipation substrate) characterized in that one or more flow paths for passing a cooling medium are embedded in a plate made of a high thermal conductive material of K or more. Furthermore, according to the present invention, one or more flow paths for passing a cooling medium are embedded in a substrate made of a highly heat-conductive substance having a thermal conductivity of 10 W / cm · K or more, and the substrate has Provided is an element mounting device having at least one heating element having a maximum heat generation density of 1 W / cm ² or more. Furthermore, the present invention has a thermal conductivity of 10 W / cm.
-Two or more substrates in which one or more flow paths for passing a cooling medium are embedded in a substrate made of a high thermal conductive material of K or more are stacked, and each substrate is Provided is a semiconductor device, wherein one or more electronic elements are mounted, and metal wiring for connecting the electronic elements is arranged on or in the substrate.

The specific contents of the present invention will be disclosed in detail below. In one mode of the substrate of the present invention, the high thermal conductive material layer is laminated on the base material, and a groove for flowing a refrigerant is provided at the interface between the high thermal conductive material layer and the base material. Formed on the side. That is, the heat generated from the heating element such as a semiconductor device arranged on the surface of the high thermal conductive material layer is transmitted through the high thermal conductive material layer with a small temperature gradient and passes through the groove formed on the back surface of the material layer. Is efficiently removed by the refrigerant.

As the high thermal conductivity material layer, it is preferable that the thermal conductivity is higher because the element temperature can be suppressed. The higher the thermal conductivity, the better, but 10 W / cm · K or more is suitable. Examples of substances having such a material include natural diamond, high-pressure synthetic diamond, and vapor-phase synthetic diamond. All of these are suitable as the high thermal conductive material layer in the present invention,
In particular, when diamond obtained by the vapor phase synthesis method is used, a relatively large area high thermal conductivity material layer can be obtained at low cost. The thermal conductivity is generally temperature-dependent, and the thermal conductivity of the diamond decreases with increasing temperature in the temperature range above room temperature. In the case of a substrate on which an ordinary element (for example, an electronic element such as a semiconductor element) is mounted, the temperature of the mounted element is 100 ° C to 200 ° C or less at most, and the thermal conductivity is 10 W / cmK in this temperature range. The above is also preferable in the high thermal conductive material layer in the present invention. The thickness of the high thermal conductive material layer is at least 30 μ
It is preferably m or more, and more preferably 70 μm or more. The upper limit of the thickness of the highly conductive material layer is usually 10 mm, for example 5 mm. The high thermal conductivity material may be semi-conductive or conductive, but is preferably insulative.
The resistivity of the high thermal conductive material is preferably 1 × 10 ⁸ Ω · cm or more, more preferably 1 × 10 ⁹ Ω · cm or more.

The groove typically has a rectangular cross section. Regarding the grooves existing in the high thermal conductive material layer, the deeper the depth, the higher the heat exchange rate, but if it is too deep, the mechanical strength becomes weak, which is not preferable. Specifically, the depth (c) of the groove is 20 μm or more, more preferably 50 μm or more. The depth (c) of the groove is 90% or less of the thickness of the high thermal conductive material layer, more preferably 8
It is preferably 0% or less, for example 70% or less. Also, the wider the width (a) of the groove, the higher the heat exchange rate, but instead the number of grooves is reduced in order to maintain the strength of the portion in contact with the base material. become worse. On the other hand, the groove spacing (b) is similar to the width, and it is neither too wide nor too narrow. Groove width (a) and spacing (b)
Is preferably 20 μm or more and 10 mm or less, more preferably 40 μm or more and 2 mm or less, and even more preferably 50 μm or more and 2 mm or less. Regarding the range of the ratio of the length of the width (a) to the length of the interval (b) (a / b), the lower limit is 0.02, more preferably 0.04, while the upper limit is 50, more preferably 25. Is desirable. Regarding the range of the ratio (a / c) of the length of the width (a) to the depth (c), the lower limit is
0.05, more preferably 0.1, while the upper limit is 1
00, more preferably 50 (FIG. 7)
reference).

However, the optimum widths and intervals depend on the elements mounted on the heat dissipation board. The shape of the groove does not have to be rectangular in cross section, and may be semicircular, semielliptic, or a more complicated shape. Further, the values of a, b, and c described above do not have to be constant in one substrate, and can be changed under the conditions shown above. The ratio of the surface of the high thermal conductive material layer occupied by the groove is usually 2 to 90% in the case of the substrate with respect to the surface area of the high thermal conductive material layer,
It is preferably 10 to 80%. Angle (taper angle) between the side surface of the groove and the vertical line with respect to the surface of the high thermal conductive material layer
Is preferably 30 ° or less.

The groove through which the coolant passes can be appropriately formed according to the arrangement of the heating element such as a semiconductor element installed on the main substrate. It is desirable to form the groove so that the portion that generates the most heat or the portion that requires the lowest temperature is cooled most efficiently by the heating element such as the mounted semiconductor element. Specifically, the grooves are arranged so that the refrigerant most passes through the portion to be cooled most. The cooling efficiency can also be improved by making the cross-sectional shape of the groove complicated and increasing the surface area of the groove. Also,
Since the temperature of the refrigerant is lowest near the inlet of the refrigerant, the cooling efficiency is high. Therefore, if the calorific value distribution of the heating element is almost even, the temperature will be highest in the central part, so it is efficient to provide an inlet in the central part and arrange the refrigerant groove in a spiral or radial shape from there. Good.

The groove is formed after forming the high thermal conductive material layer.
The material layer can be formed by laser processing (for example, using an excimer laser), processing by an etching method, or the like. A layer of a non-diamond carbon component (for example, graphite or amorphous carbon) having a thickness of 1 nm or more and 1 μm or less may be present on the surface of the groove. The non-diamond layer is formed by subjecting the high thermal conductive material layer to a temperature of 1000 to 1500 ° C. for 30 minutes to 10 hours (eg, 1 to 1) in a non-oxidizing atmosphere (for example, an inert gas atmosphere).
It can be formed by heating for a time (in this case, a non-diamond layer is also formed on the surface of the high thermal conductive material layer other than the groove, which can be removed by polishing or the like). .). The presence or absence of the non-diamond layer can be measured by Raman spectroscopy.

It is preferable that the surface of the groove has good wettability with the refrigerant. The contact angle is usually 65 ° or less, more preferably 60 ° or less.
Since hydrogen atoms are present on the surface of diamond, in this state, it repels a coolant such as water. Therefore, instead of a hydrogen atom, a hydrophilic group containing an oxygen atom (for example, OH
By adding a base), the hydrophilicity of the diamond layer surface can be increased. In order to improve the wettability of the surface of the groove, for example, annealing is performed at 500 to 800 ° C. for 10 minutes to 10 hours in an oxidizing atmosphere (for example, air atmosphere), or treatment with oxygen or a gas plasma containing oxygen is performed. do it. When oxygen plasma is used as the method for forming the grooves, it is considered that the hydrophilicity is increased to some extent, but the above-mentioned operation for improving wettability may be further performed. Further, as the treatment for improving the wettability of the surface of the groove with respect to the coolant, in addition to the above, plasma treatment in a gas containing nitrogen, boron or an inert gas can be mentioned.

After forming the groove, the high thermal conductivity layer is attached to the substrate. The bonding may be performed with a metal or an adhesive. The thickness of the metal layer or adhesive layer is usually 0.
It is from 01 to 10 μm. Alternatively, the bonding may be performed by directly attaching the high thermal conductivity layer to the base material without using a substance such as metal.

The base material is, for example, B, Be, Al, Cu,
It is made of materials such as Si, Ag, Ti, Fe, Ni, Mo, W, alloys thereof and compounds thereof (for example, carbides and nitrides). The substrate may be insulative, for example. The substrate may be plate-shaped. The thickness of the substrate is
It is usually 0.1 to 10 mm, preferably 0.5 to 5 mm.

When the device is mounted on the substrate, the device is preferably arranged on the high thermal conductive material layer. As the refrigerant, for example, water, air, an inert gas (for example, nitrogen, argon, etc.), fluorocarbon, liquid nitrogen, liquid oxygen, liquid helium, etc. are used. The substrate of the present invention is a semiconductor device such as a laser chip or MPU.
It is useful in The element used in the present invention is preferably a semiconductor element (for example, a semiconductor laser, MPU (microprocessor unit), IC). When the substrate as in the present invention is used, the element is efficiently cooled and the temperature rise of the element is prevented. When the element temperature rises, the oscillation wavelength of the semiconductor laser generally shifts to the long wavelength side. However, in the present invention, since the element temperature does not rise, the oscillation wavelength of the semiconductor laser does not shift to the long wavelength side.

Now, a method for manufacturing a substrate having the groove through which the coolant passes at the interface between the base material and the high thermal conductive material layer will be described below. First, a method of adhering a high thermal conductive substance layer having a coolant passage groove to a base material will be described. A substance to be the high thermal conductive substance layer is prepared in a desired size. In order to arrange the groove through which the coolant passes, a processing method using a laser beam, selective etching, or the like can be used. In the laser processing, the material is removed by focusing a laser beam on the surface of the material to form a groove on the surface. According to this method, it is possible to obtain grooves having an arbitrary arrangement. A laser beam having a sufficient energy density is focused on the surface of the high thermal conductivity material, and the focusing position is gradually moved while deleting the material to form a groove on the surface. As the laser beam, a YAG laser, an excimer laser, or the like can be used, and in particular, the excimer laser is preferable because it can form a groove having an arbitrary depth and arrangement with good reproducibility in terms of its processing accuracy.

The wavelength of the laser light is preferably 360 nm or less, for example, in the range of 190 to 360 nm. The energy density of the irradiation light is 10 to 10 ¹¹ W / cm ² . Energy density per pulse is 10 ^-1 J / cm ² or more using pulsed laser light and 10 ⁶ J / cm 2
The range is preferably ² or less. Furthermore, the divergence angle of the laser light when oscillated by the laser oscillator is 1
It is preferable to set it to 0 ^{−2 to 5} × 10 ⁻¹ mrad, and to set the half width of the oscillation spectrum of the laser beam to 10 ⁻⁴ to 1 nm. The uniformity of energy distribution in the beam cross section of the laser light is preferably 10% or less. Good processing results are obtained by focusing the pulsed laser light with a cylindrical lens or a cylindrical mirror. In such surface groove processing by the excimer laser, by performing the processing in an appropriate atmosphere, the diamond surface can be modified and the wettability with the refrigerant can be improved. For example, by performing the above-mentioned processing in the atmosphere of an amino group-containing compound (for example, ammonia, hydrazine, etc.), an amino group can be introduced into the surface of the formed groove, and hydrophilicity can be improved.

On the other hand, the surface groove processing by the etching method is
It can be done as follows. That is, after forming an appropriate mask on the high thermal conductive material layer, the mask is not etched, and only the high thermal conductive material is etched. After that, the mask is removed to obtain a high thermal conductive material layer having grooves on the surface. It is known that Al or SiO ₂ can be formed as a mask material on diamond and the diamond can be selectively etched by oxygen or a gas containing oxygen (53rd Proceedings of the Society of Physical and Chemical Engineering, Second Volume, Volume 411). (See page), this technology can be used to form grooves on diamond. Alternatively, nitrogen or hydrogen may be used instead of oxygen or a gas containing oxygen.

By attaching the high thermal conductive material layer having the desired groove thus formed to a base material prepared separately,
It is possible to obtain a substrate having a very large heat dissipation efficiency. The base material is provided with an inlet / outlet for introducing the cooling medium to be separately passed through the groove provided in the layer.

Adhesion between the high thermal conductive material layer and the substrate is
It can be performed by a metallizing process or by an adhesive. It may be performed by metalizing the two surfaces to be bonded by a known method and melting the metal. Examples of metals used in the metallization treatment are Ti, P
t, Au, Sn, Pb, In, Ag and the like. Adhesive (eg Ag / epoxy type, Ag / polyimide type, A
u / epoxy based) or Ag based brazing agents, and other bonding methods may be used. The thickness of the adhesive layer is usually 0.0
It is 1 to 10 μm.

When diamond synthesized by the vapor phase synthesis method is used as the high thermal conductive material layer, selective growth using a mask should be used to form the groove, rather than processing by laser beam or etching method. You can This is disclosed in, for example, Japanese Patent Laid-Open No. 1-1047661,
It is disclosed in Japanese Laid-Open Patent Publication No. 1-123423. If a mask material is placed on the surface of a base material (for example, Si, SiC, Cu, Mo, cBN, etc.) in a shape corresponding to the groove in which the mask material is to be formed, and diamond is laminated thereon by the vapor phase synthesis method. Good. At this time, by growing the diamond by 50 μm or more, the diamond grows laterally also on the upper part of the mask, and as a result, the whole surface is covered. After that, if the base material is removed by a method such as melting, the diamond taken out has grooves on the base material surface side. The mask is
Ti, SiO ₂ , Mo and the like may be formed by a known method. The advantage of this method is that since it is not necessary to give an impact after growing the diamond, it is unlikely to be damaged during processing.

In the above method, instead of forming a mask, the plate-shaped material itself is processed to form irregularities in a shape corresponding to the groove, and diamond can be grown on it by vapor phase synthesis. . When the plate-shaped material is removed after the growth to a desired thickness, a diamond free-standing film having a groove on the plate-shaped material surface side can be obtained. Examples of the plate-shaped material include Si, SiC, Mo and the like.

Furthermore, when vapor phase synthetic diamond is used as the high thermal conductivity material layer, the above method is developed,
The step of bonding can be omitted. That is, a mask is first placed on the base material, and after vapor phase synthetic diamond is grown on the base material, only the mask is melted to form a groove through which a coolant passes on the diamond side of the interface between the base material and the diamond. A substrate having can be obtained. According to this method, since it is not necessary to use an adhesive material, the heat dissipation efficiency of the entire substrate can be further increased. As such a base material, Si, SiC, Cu and Mo are preferable.

In any of the above methods, the high thermal conductivity material layer /
This is effective for manufacturing a substrate having a groove on the high thermal conductive layer side of the interface of the base material. The etching method can form fine grooves with high precision. The method using laser processing has a high formation speed. Further, in the method using selective growth (method using a mask), it is easy to form a relatively large groove.

In another form of the substrate according to the present invention,
The upper and lower directions and the lateral direction of the flow path are surrounded by the high thermal conductive material. That is, the heat generated from an element (for example, a semiconductor element) arranged on the surface of the substrate is transmitted through the high thermal conductivity material with a small temperature gradient, and is efficiently removed by the refrigerant passing through the flow path.

As the high thermal conductivity material, it is preferable that the thermal conductivity is higher because the element temperature can be suppressed. The higher the thermal conductivity, the better, but 10 W / cm · K or more is suitable. Examples of substances having such a material include natural diamond, high-pressure synthetic diamond, and vapor-phase synthetic diamond. All of these are suitable as the high thermal conductivity substance in the present invention, but particularly when diamond obtained by the vapor phase synthesis method is used, a relatively large area high thermal conductivity substance can be obtained at low cost. The thermal conductivity is generally temperature-dependent, and the thermal conductivity of the diamond decreases with increasing temperature in the temperature range above room temperature. In the case of a board on which an ordinary electronic element is mounted, the temperature of the mounted element is 100 ° C to 20 ° C at best.
It is below 0 ℃, and the thermal conductivity is 10W / cm in this temperature range.
-It is preferable that it is K or more also in the high thermal conductive material in the present invention. The thickness of the substrate is preferably 30 μm or more, more preferably 70 μm or more. The upper limit of the thickness of the substrate is usually 10 mm, for example 5 mm. The high thermal conductivity material may be semi-conductive or conductive, but is preferably insulative. The high thermal conductivity material has a resistivity of 1 × 10 ⁸ Ω · cm or more, more preferably 1 × 1.
It is preferably not less than ⁰⁹ Ω · cm.

The flow path is typically rectangular in cross section. The heat exchange rate increases as the height of the flow path increases, but if it is too high, the mechanical strength of the flow path decreases, which is not preferable. Specifically, the height (c) of the flow path is 20 μm or more, more preferably 50 μm or more. The height (c) of the flow path is 90% or less of the thickness of the substrate,
It is more preferably 80% or less, for example 70% or less. Further, the wider the width (a) of the flow path, the higher the heat exchange rate, but since the number of flow paths is reduced in order to maintain the strength of the substrate, the heat exchange rate deteriorates if the width is too wide. On the other hand, the spacing (b) of the flow paths is the same as the width, and it is neither too wide nor too narrow. The width and spacing of the flow path is 20μ
It is desirable that the thickness is m or more and 10 mm or less, more preferably 40 μm or more and 2 mm or less, and even more preferably 50 μm or more and 2 mm or less. Regarding the range of the ratio (a / b) of the width (a) and the interval (b), the lower limit is 0.02, more preferably 0.0.
On the other hand, it is desirable that the upper limit is 4, while the upper limit is 50, more preferably 25. Ratio of width (a) to height (c) (a /
Regarding the range of c), it is desirable that the lower limit is 0.05, more preferably 0.1, while the upper limit is 100, more preferably 50.

However, regarding the optimum width, spacing, and height,
It depends on the device mounted on the substrate. The shape of the flow path does not have to be rectangular in cross section, and may be semicircular, semielliptic, or a more complicated shape. Also, it is not necessary that the values of a, b, and c are constant in one board,
It can be varied within the conditions given above. The ratio of the surface of the substrate occupied by the flow channel (the ratio of the area occupied by the flow channel on the surface of the substrate when viewed in the direction perpendicular to the plane of the substrate) is
It is 2 to 90%, preferably 10 to 80%. The angle (taper angle) between the side surface of the flow path and the vertical line with respect to the surface of the substrate is preferably 30 ° or less.

The flow path can be appropriately formed according to the arrangement of the electronic elements installed on the substrate. It is desirable that the flow path be formed so that the electronic element mounted therein can most efficiently cool the part that generates the most heat or the part that requires the lowest temperature. Specifically, the flow passages are arranged so that the refrigerant most passes through the portion to be cooled most. The cooling efficiency can also be improved by making the cross-sectional shape of the flow channel complicated and increasing the surface area of the flow channel.
Also, since the temperature of the refrigerant is the lowest near the inlet of the refrigerant,
Higher cooling efficiency. Therefore, when the heat generation distribution of the electronic element is almost uniform, the temperature becomes highest in the central part, so it is efficient to provide an inlet at the central part and arrange the refrigerant flow path spirally or radially from there. Good.

A layer made of a non-diamond carbon component (for example, graphite or amorphous carbon) having a thickness of 1 nm or more and 1 μm or less may be present on the surface of the channel. The non-diamond layer is formed of a high thermal conductive material film of 1000 to 1500 in a non-oxidizing atmosphere (for example, an inert gas atmosphere).
It can be formed by heating at 30 ° C. for 30 minutes to 10 hours (for example, 1 hour) (in this case, the non-diamond layer is also formed on the surface of the substrate other than the flow channel. It can be removed by polishing etc.). The presence or absence of the non-diamond layer can be measured by Raman spectroscopy.

It is preferable that the surface of the channel has good wettability with the refrigerant. The contact angle is usually 65 ° or less, more preferably 60 ° or less.
Since hydrogen atoms are present on the surface of diamond, in this state, it repels a coolant such as water. Therefore, instead of a hydrogen atom, a hydrophilic group containing an oxygen atom (for example, OH
By adding a base, the hydrophilicity of the diamond film surface can be increased.

In order to improve the wettability of the surface of the channel, for example, in an oxidizing atmosphere (for example, atmospheric air), 50
It may be annealed at 0 to 800 ° C. for 10 minutes to 10 hours, or may be treated with plasma of oxygen or a gas containing oxygen. When oxygen plasma is used as the method of forming the flow channel, it is considered that the hydrophilicity is increased to some extent, but the above-mentioned operation for improving wettability may be further performed.

Further, as the treatment for improving the wettability of the surface of the flow path with respect to the refrigerant, there can be mentioned plasma treatment in a gas containing nitrogen, boron or an inert gas in addition to the above.

As the refrigerant, for example, water, air, inert gas (for example, nitrogen, argon, etc.), fluorocarbon, liquid nitrogen, liquid oxygen, liquid helium, etc. are used. The element used in the present invention is preferably a semiconductor element, for example, a semiconductor laser chip, MPU (microprocessor unit), or IC. When the substrate as in the present invention is used, the device is efficiently cooled,
The temperature rise of the element is prevented. When the element temperature rises,
Generally, the oscillation wavelength of the semiconductor laser shifts to the long wavelength side, but in the present invention, since the element temperature does not rise,
The oscillation wavelength of the semiconductor laser does not shift to the long wavelength side.

Now, a method of manufacturing a substrate having a channel surrounded by a high thermal conductive material will be described below. The substrate can be formed by directly making holes in the substrate to form a flow path by, for example, laser processing. Alternatively, the substrate can be formed by forming a groove in one film and then bonding another film.

In the former method, first, a plate made of a highly heat-conductive substance having a desired shape is prepared, and a laser beam is focused on this side surface to form a hole, and a coolant is placed inside the high-heat conductive substance plate. A flow passage is formed.

A method of obtaining the first high thermal conductivity substance film and the second high thermal conductivity substance film by bonding is shown below. The first high thermal conductivity material film has a groove that serves as a flow channel, and the second high thermal conductivity material film has no groove.
A film made of a material having high thermal conductivity is prepared in a desired size.
On one surface of the first high thermal conductivity material film, a flow path to be embedded inside at the time of completion is formed by a laser beam processing method, a selective etching processing method, or the like.

In the laser processing, the material is removed by focusing a laser beam on the surface of the material to form a groove on the surface. According to this method, it is possible to obtain a flow path having an arbitrary arrangement. A laser beam having a sufficient energy density is focused on the surface of the high thermal conductivity material, and the focusing position is gradually moved while deleting the material to form a groove on the surface. As the laser beam, a YAG laser, an excimer laser, or the like can be used. In particular, the excimer laser is preferable because it can form a flow path having an arbitrary depth and arrangement with good reproducibility in terms of its processing accuracy.

The wavelength of the laser light is preferably 360 nm or less, for example, in the range of 190 to 360 nm. The energy density of the irradiation light is 10 to 10 ¹¹ W / cm ² . Energy density per pulse is 10 ^-1 J / cm ² or more using pulsed laser light and 10 ⁶ J / cm 2
The range is preferably ² or less. Furthermore, the divergence angle of the laser light when oscillated by the laser oscillator is 1
It is preferable to set it to 0 ^{−2 to 5} × 10 ⁻¹ mrad and to set the half width of the oscillation spectrum of the laser beam to 10 ⁻⁴ to 1 nm. The uniformity of energy distribution in the beam cross section of the laser light is preferably 10% or less. Good processing results are obtained by focusing the pulsed laser light with a cylindrical lens or a cylindrical mirror. In such surface groove processing by the excimer laser, by performing the processing in an appropriate atmosphere, the diamond surface can be modified and the wettability with the refrigerant can be improved. For example, by performing the above-mentioned processing in the atmosphere of an amino group-containing compound (for example, ammonia, hydrazine, etc.), an amino group can be introduced into the surface of the formed groove, and hydrophilicity can be improved.

On the other hand, the flow path formation by the etching method can be performed as follows. That is, after forming an appropriate mask on the high thermal conductive material film, the mask is not etched, and only the high thermal conductive material is etched. After that, the mask is removed to obtain a first high thermal conductive material film having grooves on the surface. It is known that Al or SiO ₂ can be formed as a mask material on diamond and the diamond can be selectively etched by oxygen or a gas containing oxygen (53rd Proceedings of the Society of Physical and Chemical Engineering, Second Volume, Volume 411). (See page), this technology can be used to form grooves on diamond. Alternatively, nitrogen or hydrogen may be used instead of oxygen or a gas containing oxygen.

By adhering the first high thermal conductivity material film having the desired groove formed thereon to the separately prepared second high thermal conductivity material film, it is possible to obtain a substrate having a very high heat dissipation efficiency. The second high thermal conductive material film may be separately provided with an inlet / outlet for introducing a cooling medium to be passed through the flow path.

Although the method of forming the groove only on the first high thermal conductive material film has been described above, the groove is also formed on the second high thermal conductive material film, and the surfaces having both grooves are bonded to each other. You can also However, in this case, since the process becomes complicated, it is preferable to form the groove only in the first high thermal conductive material film.

The first high thermal conductivity substance film and the second high thermal conductivity substance film can be attached by a metallizing treatment or an adhesive. It may be performed by metalizing the two surfaces to be bonded by a known method and melting the metal. Examples of metals used in the metallization treatment are Ti, Pt, Au, Sn, Pb, In, Ag.
And so on. Adhesives (eg Ag / epoxy, Ag
/ Polyimide based, Au / epoxy based) or Ag based brazing agents, and other bonding methods may be used. The thickness of the adhesive layer is usually 0.01 to 10 μm.

When diamond synthesized by the vapor phase synthesis method is used as the high thermal conductive material film, the selective growth using a mask should be used to form the groove, instead of processing by a laser beam or an etching method. You can This is disclosed in, for example, Japanese Patent Laid-Open No. 1-1047661,
It is disclosed in Japanese Laid-Open Patent Publication No. 1-123423. If a mask material is placed on the surface of a base material (for example, Si, SiC, Cu, Mo, cBN, etc.) in a shape corresponding to the groove in which the mask material is to be formed, and diamond is laminated thereon by the vapor phase synthesis method. Good. At this time, by growing the diamond by 50 μm or more, the diamond grows laterally also on the upper part of the mask, and as a result, the whole surface is covered. After that, if the base material is removed by a method such as melting, the diamond taken out has grooves on the base material surface side. The mask is
Ti, SiO ₂ , Mo and the like may be formed by a known method. The advantage of this method is that since it is not necessary to give an impact after growing the diamond, it is unlikely to be damaged during processing.

In the above method, instead of forming a mask, the plate-shaped material itself is processed to form irregularities in a shape corresponding to the groove, and diamond can be grown on it by vapor phase synthesis. . When the plate-shaped material is removed after the growth to a desired thickness, a diamond free-standing film having a groove on the plate-shaped material surface side can be obtained. Examples of the plate-shaped material include Si, SiC, Mo and the like.

Further, when vapor phase synthetic diamond is used as the high thermal conductive material film, the above method is developed,
The step of bonding can be omitted. That is, a substrate having a channel can be obtained by first attaching a mask on the diamond film, growing vapor-phase synthetic diamond on the diamond film, and then dissolving only the mask. According to this method, since it is not necessary to use an adhesive material, the heat dissipation efficiency of the entire substrate can be further increased.

Any of the above methods is effective for manufacturing a substrate having a flow path. The etching method can form fine grooves with high precision. The method using laser processing has a high formation speed. Further, in the method using selective growth (method using a mask), it is easy to form a relatively large groove.

Holes are formed in the substrate thus obtained by drilling with a laser beam. This hole can also be obtained by, for example, selective growth or etching at the stage of manufacturing the substrate. Electrical wiring is appropriately formed in the holes and on the substrate. A plurality of substrates each having electrical wiring are stacked to obtain a semiconductor device. Electrical connection between the substrates is made by electrical wiring in the holes. The number of substrates in the semiconductor device is at least two or more. The number of substrates may be 200 or less, for example 50 or less. Then, the coolant is caused to flow into the flow path of each substrate from a part of the semiconductor device, for example, the side surface of the substrate.

The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a plan view showing the concept of a grooved high thermal conductivity material layer in the present invention. The high thermal conductive material layer 11 includes
Groove 1 so that the surface without grooves is comb-shaped
Two are provided. FIG. 2 is a front view of the heat dissipation board in the present invention. The heat dissipation substrate 16 is the high thermal conductive material layer 1
1, a base material 13 and an adhesive layer 15. Substrate 1
Three refrigerant inlets / outlets 14 communicating with the groove 12 are provided in 3. The size and number of the refrigerant inlet / outlet ports 14 in the base material 13 are not particularly limited. For example, there may be a refrigerant inlet / outlet on each of the portions of the substrate that correspond to the ends of the groove.

FIG. 3 is a plan view showing the concept of the grooved high thermal conductive material layer in the present invention. High thermal conductive material layer 21
The groove 22 is formed in the spiral shape. FIG. 4 is a plan view showing the concept of the grooved AlN layer of Comparative Example 1 which is not included in the present invention. A groove 32 having the same shape as that of FIG. 1 is formed in the AlN layer 31. FIG. 5 is a front view of a heat dissipation substrate using a grooved AlN layer in Comparative Example 1 which is not included in the present invention. The heat dissipation substrate 36 includes the AlN layer 31 and the base material 33.
And an adhesive layer 35. The groove 33 is formed on the base material 33.
Two refrigerant inlet / outlet ports 34 communicating with the two are provided.

FIG. 6 is a side view showing the concept of the conventional heat dissipation board in Comparative Example 2 which is not included in the present invention. The substrate 46 includes a diamond layer 41 having no groove, a base material 43, and an adhesive layer 45. FIG. 7 is a cross-sectional view showing a groove formed in the high thermal conductivity material layer according to the present invention. The groove 12 has a width a and a depth c,
It is formed with a space b.

FIG. 8 shows the Raman spectra of diamond and non-diamond carbon. Curve a is the spectrum of diamond and has a strong peak at 1333 cm ^-1 . A curve b is a spectrum of a substance containing a large amount of non-diamond carbon and has two broad peaks. FIG. 9 is a plan view showing the substrate of the present invention in which the high thermal conductive material surrounds the periphery of the flow path. A flow channel 112 is formed in the substrate 111, and the flow channel 112 is embedded inside the substrate.

FIG. 10 is a front view of the substrate of FIG. The substrate 111 includes a first high thermal conductivity substance film 113 having a flow channel 112 formed therein, a second high thermal conductivity substance film 114, and an adhesive layer 115. The flow path 112 is connected to the two refrigerant inlet / outlets 116. The refrigerant inlet / outlet 116 may not be located at such a position, and the first high thermal conductive material film 1 may be provided.
13 or the main surface of the second high thermal conductivity substance film 114 may be provided. The size and number of the refrigerant inlet / outlet ports are not particularly limited.

FIG. 11 is a plan view showing another substrate of the present invention in which the high thermal conductive material surrounds the flow path. Board 12
1, the channels 122 are radially formed. There is another channel 123 connected to the channel 122 so as to surround the radial channel 122. The flow path 122 is connected to the refrigerant inlet 124, and the flow path 123 is connected to the refrigerant outlet 125. FIG. 12 is a sectional view showing a flow path formed in the substrate in the present invention. The flow path 112 has a width a and a height c, and is formed at intervals b.

FIG. 13 shows a semiconductor device of the present invention (three-dimensional I
It is a perspective view showing (C board). The semiconductor device 210 has four
It has two substrates 201. Each substrate 201 is made of diamond and is similar to the substrate shown in FIG. Each substrate 201 has two refrigerant inlets / outlets 206 and nine ICs 209. Figure 14
FIG. 14 is a sectional view of a part of the semiconductor device of FIG. 13. Two substrates 201 are visible in FIG. An IC (electronic element) 209 and a metal wiring 208 are provided on the substrate 201. The metal wiring (for example, Au) 208 is provided in the via hole 2
04 and the solder bump 205, it is connected to the metal wiring 208 on another substrate. The substrate 201 is
It has a flow path 202 through which the cooling medium passes. FIG. 15 is a plan view showing another substrate in the present invention in which the high thermal conductive material surrounds the flow path. The high thermal conductive material 221 includes
The flow path 222 is embedded in a spiral shape.

[0062]

EXAMPLES The present invention will be specifically disclosed below with reference to examples. Example 1 CVD, laser grooving, attachment: Diamond was grown by a microwave plasma CVD method on a scratch-treated polycrystalline Si substrate (10 mm x 10 mm x thickness 2 mm). The growth conditions are methane 1% -hydrogen system, pressure 80 Tor.
The substrate temperature was 900 ° C. After the growth for 400 hours, the growth surface was polished and the Si substrate was dissolved with an acid to obtain a self-supporting diamond film of 10 mm × 10 mm × thickness 0.5 mm. The thermal conductivity was measured to be 17.2 W / cm.
It was K.

A KrF excimer laser was line-focused and point-focused on one surface of the diamond free-standing film thus obtained to form a groove as shown in FIG. The groove depth is about 150μ
m, the width was about 500 μm, and the interval was about 400 μm. After Ti, Pt and Au were vapor-deposited on both of them, the grooved diamond was adhered onto the CuW alloy by melting Au. Thickness of Ti / Pt / Au / Pt / Ti layer is 0.1 μm
Met. The CuW alloy is provided in advance with a refrigerant inlet / outlet (diameter: 400 μm) to be introduced into the diamond groove (FIG. 2).

Grooved diamond / made as described above
Cooling water (water temperature 25 ° C.) was supplied to the grooves of the CuW substrate.
The thermal resistance between the surface of the diamond and the water of the coolant was measured and found to be 0.014 ° C./W. Infrared emitting laser semiconductor device (1 mm on the diamond layer of the grooved substrate)
x 1 mm x 0.5 mm) (output density 5.3 W / cm ² ) was mounted and predetermined wiring was performed to fabricate a laser element mounting device. Wirings made of metal (Au) were formed on the diamond surface by ordinary patterning. Cooling water (water temperature 25 ° C.) was supplied to the groove of the laser element mounting device. When the laser element was oscillated, no change (especially change in oscillation wavelength) was observed over a long period of time.

Example 2 High-pressure synthesis, grooving laser, pasting: Ib type diamond (8 mm × 8 mm × thickness 0.6 mm, synthesized under high temperature and high pressure)
A grooved diamond / CuW substrate was prepared in the same manner as in Example 1 using a thermal conductivity of 18.3 W / cmK. However, the grooves formed in the diamond are formed by using an ArF excimer laser and have a depth of about 200 μm, a width of about 350 μm, and an interval of about 400 μm.
m (Fig. 3). As a refrigerant inlet / outlet for the base material, 2
Holes (circles with a diameter of about 350 μm) were formed at points by focusing with a KrF excimer laser.

Cooling water (water temperature: 25 ° C.) was supplied to the grooves of the grooved diamond / CuW substrate thus manufactured in the same manner as in Example 1. At this time, the thermal resistance between the water of the coolant and the surface of the diamond was measured and found to be 0.021 ° C./W. Infrared emitting laser semiconductor device (1mm x 1mm x 0.5mm) on the diamond layer of the substrate (power density 5.3W
/ Cm ² ) was mounted and predetermined wiring was performed to fabricate a laser element mounting device. Metal (A
The wiring according to u) was formed by ordinary patterning.
Cooling water (water temperature 25 ° C.) was supplied to the groove of the laser element mounting device. When the laser element was oscillated, no change (especially change in oscillation wavelength) was observed over a long period of time.

Comparative Example 1 AlN with groove: AlN base material (10 mm × 10 mm × 0.5 m)
m, thermal conductivity of 1.9 W / cmK) on one side,
Similarly, a KrF excimer laser was used to linearly collect light rays to form grooves (FIG. 4). The groove depth is about 150μ
m, the width was about 500 μm, and the spacing was about 400 μm. This grooved AlN was bonded onto a CuW alloy. The CuW alloy is preliminarily provided with an inlet / outlet for a refrigerant to be introduced into the groove of AlN (FIG. 5). Grooved Al produced as described above
Cooling water (water temperature 25 ° C.) was supplied to the groove of the N / CuW substrate. At this time, the thermal resistance between the surface of the AlN and the water of the refrigerant was measured and found to be 0.098 ° C./W.

On the AlN layer of the substrate, an infrared emitting laser semiconductor device (1 mm x 1 mm x 0.5 mm) (power density 5.3)
W / cm ² ) was mounted and predetermined wiring was performed to fabricate a laser element mounting device. Metal (Au) on the AlN surface
The wiring was formed by ordinary patterning. Cooling water (water temperature 25 ° C.) was supplied to the groove of the laser element mounting device. When the laser element was oscillated, it was observed that the oscillation wavelength gradually shifted to the long wavelength side.

Comparative Example 2 CVD, No Groove: As in Example 1, vapor phase synthetic diamond 1
0mmx10mmx0.5mm self-supporting film (thermal conductivity 17.2W / c
m · K) was prepared. In this, without forming a groove, C
Bonded to uW alloy (Fig. 6). The thermal resistance of the thus-produced diamond / CuW substrate was measured while blowing air at 25 ° C. on the back surface of the CuW substrate and found to be 3.4 ° C./W. Infrared emitting laser semiconductor device (1mm x 1mm x 0.5mm) on the diamond layer of the substrate (power density 5.3
W / cm ² ) was mounted to prepare a laser element mounting device. When the laser element was oscillated while blowing air at 25 ° C. from the back side of the laser element mounting device, it was observed that the oscillation wavelength gradually shifted to the long wavelength side.

Comparative Example 3 CVD, groove too thin: As in Example 1, a vapor phase synthetic diamond 10 mm × 10 mm × 0.5 mm self-supporting film (thermal conductivity: 17.2 W)
/ Cm · K) was produced. Then, a KrF excimer laser was used to linearly focus the light beam to form a groove. The grooves had a depth of about 150 μm, a width of 10 μm, and an interval of 990 μm. The grooved diamond was bonded onto a CuW alloy.
The CuW alloy was previously provided with an inlet / outlet for a refrigerant to be introduced into the groove of the CVD diamond.

A grooved diamond produced as described above /
Cooling water (water temperature 25 ° C.) was supplied to the grooves of the CuW substrate.
At this time, the thermal resistance between the diamond surface and the coolant water was measured and found to be 0.34 ° C./W.

An infrared emitting laser semiconductor device (1 mm x 1 mm x 0.5 mm) (output density 5.3 W / cm ² ) was mounted on the diamond layer of the substrate to prepare a laser device mounting device. Water for cooling (water temperature 2
5 ° C.) was supplied. When oscillating the laser element,
It was observed that the oscillation wavelength gradually shifted to the long wavelength side.

Table 1 shows the results obtained in Examples 1 and 2 and Comparative Examples 1 to 3.

[0074]

[Table 1]               Example 1 2 Comparative Example 1 2 3   High thermal conductivity CVD High pressure synthesis AlN CVD CVD   Material Layer Diamond Diamond Diamond Diamond   Thermal conductivity 17.2 18.3 1.9 17.2 17.2  (W / cm / K)   Thickness (mm) 0.5 0.6 0.5 0.5 0.5 0.5   Groove width (a) 0.5 0.35 0.5 None 0.01     (mm)   Interval (b) 0.4 0.4 0.4 None 0.99     (mm)   Depth (c) 0.15 0.2 0.15 None 0.15     (mm)   a / b 1.25 0.88 1.25-0.01   Thermal resistance (℃ / W) 0.014 0.021 0.098 3.4 0.34

Example 3 Air Annealing In the same manner as in Example 1, a grooved diamond as shown in FIG. 1 was obtained. This was annealed at 600 ° C. in the atmosphere for 30 minutes, and then attached on a CuW substrate in the same manner as in Example 1. Refrigerant water (water temperature 25 ° C.) was introduced into the grooves of the grooved diamond / CuW substrate thus prepared. When the thermal resistance between the diamond surface and the coolant was examined, it was 0.012 ° C./W. An infrared emitting laser semiconductor device (1 mm x 1 mm x 0.5 mm) (output density 5.3 W / cm ² ) was mounted on the diamond layer of the grooved substrate, and predetermined wiring was performed to fabricate a laser device mounting device. . Cooling water (water temperature 25 ° C.) was supplied to the groove of the laser element mounting device. When the laser element was oscillated, no change (especially change in oscillation wavelength) was observed over a long period of time.

Example 4 Vacuum Annealing In the same manner as in Example 1, a grooved diamond as shown in FIG. 1 was obtained. This was annealed at 1200 ° C. in vacuum for 30 minutes. When Raman spectrum measurement was performed on this sample, a peak showing a non-diamond component was observed as shown in b of FIG. After that, it was stuck on the CuW substrate in the same manner as in Example 1. Grooved diamond / C produced in this way
Refrigerant water (water temperature 25 ° C.) was introduced into the groove of the uW substrate.
When the thermal resistance between the diamond surface and the coolant was examined, it was 0.011 ° C./W. Infrared emitting laser semiconductor device (1mm x 1 on the diamond layer of the grooved substrate)
mm x 0.5 mm) (output density 5.3 W / cm ² )
A predetermined wiring was performed to manufacture a laser element mounting device. Water for cooling (water temperature 25
C) was supplied. When the laser element was oscillated, no change (especially change in oscillation wavelength) was observed over a long period of time.

Example 5 On a diamond layer of a grooved substrate manufactured in the same manner as in Example 1, an MPU chip (a huge number of circuits are formed on a Si chip) is formed along with electrical wiring by the TAB technique. I placed it. Cooling water (water temperature 2
When the semiconductor element was operated while flowing (5 ° C),
It operated without malfunction for a long time.

Example 6 In the same manner as in Example 1, a grooved diamond as shown in FIG. 1 was obtained. This is heated to 100 in hydrogen by μ-wave plasma.
Processed at Torr and temperature of 800 ° C. for 30 minutes. Raman spectrum measurement of this sample was performed. Then, a sharp peak of diamond was observed as shown in FIG. After this,
It was stuck on a CuW substrate in the same manner as in Example 1. Refrigerant water (water temperature 25 ° C.) was introduced into the grooves of the grooved diamond / CuW substrate thus prepared. When the thermal resistance between the diamond surface and the cooling medium was examined, it was 0.038 ° C./W.

Example 7 CVD, Laser Flow Path Insertion, Adhesion: Two scratch-treated polycrystalline Si substrates (10 mm × 10 mm × thickness 2 mm) were prepared, and diamond was grown on them by microwave plasma CVD method. It was The growth conditions were 1% methane-hydrogen system, the pressure was 80 Torr, and the substrate temperature was 900 ° C.
After the growth of one sheet for 250 hours and the other for 200 hours, the growth surface was polished and the Si substrate was dissolved with an acid.
mm x 10mm x thickness 0.3mm and 10mm x 10mm
Two free-standing diamond films of x 0.15 mm were obtained. When thermal conductivity was measured, each was 17.2 W / cm · K
(Thickness of 0.3 mm, first freestanding diamond film) and 16.9 W / cmK (thickness of 0.15 mm, second freestanding diamond film).

On one side of the first free-standing diamond film (0.3 mm thick diamond free-standing film) obtained as described above,
Line focusing and point focusing of the KrF excimer laser,
To form a groove. The grooves had a depth of about 150 μm, a width of about 500 μm, and an interval of about 400 μm. Ti to both
After stacking Pt and Au by vapor deposition, by melting Au, the first diamond free-standing film was bonded to the second diamond free-standing film to prepare a substrate (FIGS. 9 and 1).
0). Thickness of Ti / Pt / Au / Pt / Ti layer is 0.1
It was μm. The substrate had an inlet / outlet through which a refrigerant could be injected and discharged from the side surface of the substrate.

An infrared laser semiconductor device (1 mm) was formed on the first diamond free-standing film of the substrate manufactured as described above.
x 1 mm x 0.5 mm) (output density 5.3 W / cm ² ) was mounted and predetermined wiring was performed to prepare a laser element mounting device. Wirings made of metal (Au) were formed on the diamond surface by ordinary patterning. Cooling water (water temperature 25 ° C.) was supplied to the flow path of the laser element mounting device. When the laser element was oscillated, no change (especially change in oscillation wavelength) was observed over a long period of time.

Five substrates as described above were prepared, and each had L
About 5 to 10 SI chips were mounted. Each substrate was perforated by an excimer laser for electrical wiring. The diameter of the hole is 0.1-0.5mm,
And the surface was electrically wired with Au. The five substrates manufactured as described above were stacked to obtain a semiconductor device.
This semiconductor device is an MCM using a conventional AlN substrate.
It was possible to mount an element corresponding to 30 times the total heat generation amount of the element that can be mounted on the board. Water (water temperature: 25 ° C.) was supplied as a coolant to the flow path of each substrate. The semiconductor device operated stably without causing a malfunction.

Example 8 In the same manner as in Example 7, a first freestanding diamond film and a second freestanding diamond film were obtained. However, the grooves formed in the first diamond free-standing film are radial as shown in FIG. Set the first diamond free-standing film in a vacuum furnace,
It was annealed in vacuum at 1200 ° C. for 30 minutes. When Raman spectrum measurement was performed on this self-supporting film, FIG.
As shown in b), a peak showing a non-diamond component was observed. Then, the second diamond free-standing film was attached in the same manner as in Example 7 to obtain a diamond substrate.

Five substrates as described above were prepared, and L
About 5 to 10 SI chips were mounted. Each substrate was perforated by an excimer laser for electrical wiring. The diameter of the hole is 0.1-0.5mm,
And the surface was electrically wired with Au.

The five substrates manufactured as described above were stacked to obtain a semiconductor device. This semiconductor device uses the conventional Al
It was possible to mount an element corresponding to 30 times the total heat generation amount of the element that can be mounted on the MCM board using the N board. Water (water temperature: 25 ° C.) was supplied as a coolant to the flow path of each substrate. The semiconductor device operated stably without causing a malfunction.

Example 9 High-pressure synthesis, flow-through laser, attachment: Ib type diamond synthesized under high temperature and high pressure [first diamond freestanding film (8 mm × 8 mm × thickness 0.4 mm, thermal conductivity 18.3 W / cm·
K) and the second diamond free-standing film (8 mm × 8 mm × thickness 0.2 mm, thermal conductivity 18.3 W / cm · K)] were used to prepare a diamond substrate with a flow path in the same manner as in Example 7. However,
The flow path formed in the first diamond free-standing film uses an ArF excimer laser and has a depth of about 200 μm and a width of about 350 μm.
The distance was about 400 μm, and it was as shown in FIG. The second diamond free-standing film has holes (diameter of about 350 μm) at two locations as inlets and outlets for the refrigerant introduced into the flow channel.
The circle) was processed by focusing with a KrF excimer laser.

Example 7 was placed in the flow path of the substrate thus produced.
Water for cooling (water temperature 25 ° C.) was supplied in the same manner as in. At this time, the thermal resistance between the diamond surface and the coolant water was measured and found to be 0.013 ° C./W. Infrared laser semiconductor device (1mm x
1mm x 0.5mm) (output density 5.3W / cm ² )
Predetermined wiring was performed to prepare a laser element mounting device. Wirings made of metal (Au) were formed on the diamond surface by ordinary patterning. Cooling water (water temperature 25 ° C.) was supplied to the flow path of the laser element mounting device. When the laser element was oscillated, no change (especially change in oscillation wavelength) was observed over a long period of time.

Comparative Example 4 AlN, with flow path: First AlN free-standing film (10 mm x 10
mm x thickness 0.5 mm, thermal conductivity 1.8-1.9 W / cm
Grooves were formed on one surface of (K) using a KrF excimer laser as in Example 7. The depth of the groove is about 150 μm,
The width was about 500 μm and the spacing was about 400 μm. 1A
The 1N self-supporting film is replaced with the second AlN self-supporting film (10 mm x 10 mm x
A substrate having a flow path was obtained by bonding with a thickness of 0.3 mm and a thermal conductivity of 1.8 to 1.9 W / cmK. Cooling water (water temperature 25 ° C.) was supplied to the flow path of the AlN substrate. At this time, the thermal resistance between the surface of AlN and the cooling water was measured and found to be 0.0
It was 88 ° C / W.

On the AlN layer of the substrate, an infrared laser semiconductor device (1 mm x 1 mm x 0.5 mm) (power density 5.3 W /
cm ² ) was mounted, and predetermined wiring was performed to prepare a laser element mounting device. Wirings made of metal (Au) were formed on the surface of the AlN layer by ordinary patterning. Cooling water (water temperature 25 ° C.) was supplied to the flow path of the laser element mounting device. When the laser element was oscillated, it was observed that the oscillation wavelength gradually shifted to the long wavelength side.

Comparative Example 5 CVD, no flow path: As in Example 7, a vapor phase synthetic diamond 10 mm × 10 mm × 0.5 mm self-supporting film (thermal conductivity of 17.2 W) was used.
/ Cm · K) was produced. The thermal resistance between the surface and the air was measured while blowing air at 25 ° C. on one surface thereof, and it was 2.8 ° C./W. Infrared laser semiconductor device (1mm x 1mm x 0.5m on diamond free-standing film)
m) (output density 5.3 W / cm ² ) was mounted and predetermined wiring was performed to prepare a laser element mounting device. Wirings made of metal (Au) were formed on the surface of the diamond free-standing film by ordinary patterning. When the laser element was oscillated while blowing air at 25 ° C. on the back surface of the laser element mounting device, it was observed that the oscillation wavelength gradually shifted to the long wavelength side.

Comparative Example 6 CVD, Channel Too Thin: Similar to Example 7, the first diamond free-standing film (10 mm × 10 mm × 0.3) was formed by vapor phase synthesis.
mm, thermal conductivity 17.2 W / cm · K) and a second diamond freestanding film (10 mm x 10 mm x 0.15 mm, thermal conductivity 17.2 W / cm · K) were prepared. Grooves were formed on the first free-standing diamond film by linearly focusing the light rays using a KrF excimer laser as shown in FIG. The grooves had a depth of about 150 μm, a width of 10 μm, and an interval of 990 μm. This grooved first diamond free-standing film was adhered to the second diamond free-standing film to prepare a diamond substrate. Cooling water (water temperature 25 ° C.) was supplied to the flow path of the diamond substrate. At this time, the thermal resistance between the water of the coolant and the surface of the diamond was measured and found to be 0.32 ° C./W.

An infrared laser semiconductor element (1 mm x 1 mm x 0.5 mm) (output density 5.3 W / cm ² ) was mounted on the first diamond free-standing film on the substrate, and predetermined wiring was performed to mount the laser element mounting device. Created. Wirings made of metal (Au) were formed on the diamond surface by ordinary patterning. Cooling water in the flow path of the laser element mounting device
(Water temperature 25 ° C.) was supplied. When the laser element was oscillated, it was observed that the oscillation wavelength gradually shifted to the long wavelength side.

Example 10 Air Annealing: In the same manner as in Example 7, a grooved first diamond freestanding film and a second diamond freestanding film were obtained. The first diamond free-standing film is set in an atmospheric furnace, and 600
Annealing was performed in the air at 30 ° C. for 30 minutes. After this, Example 7
Similarly, the second diamond free-standing film was attached to obtain a diamond substrate. Cooling water (water temperature 25
C) was supplied. The thermal resistance between the diamond surface and the coolant water was measured and found to be 0.01 ° C./W. A laser device mounting apparatus was obtained in the same manner as in Example 7. Refrigerant water (temperature: 25 ° C.) was introduced into the flow path of the substrate. When the laser element was oscillated, it operated stably for a long time and no change in oscillation wavelength was observed.

Example 11 Vacuum Annealing: In the same manner as in Example 7, a grooved first diamond freestanding film and a second diamond freestanding film were obtained. The first diamond free-standing film is set in a vacuum furnace, and 1200
Annealed in vacuum at 30 ° C. for 30 minutes. When Raman spectrum measurement was performed on this self-supporting film, a peak showing a non-diamond component was observed as shown in b of FIG.
Then, the second diamond free-standing film was attached in the same manner as in Example 7 to obtain a diamond substrate.

Cooling water (water temperature 25 ° C.) was supplied to the substrate. The thermal resistance between the diamond surface and the coolant water was measured and found to be 0.01 ° C./W. A laser device mounting apparatus was obtained in the same manner as in Example 7. In the flow path of the substrate,
The coolant water (temperature 25 ° C.) was introduced. When the laser element was oscillated, it operated stably for a long time and no change in oscillation wavelength was observed.

Example 12 The MPU chip (S
i-chip has a huge number of circuits)
Placed with electrical wiring due to technology. When the semiconductor element was operated while flowing cooling water (water temperature 25 ° C.) in the flow path formed in the substrate, it operated without malfunction for a long time.

[0097]

The heat dissipation board according to the present invention has high heat dissipation characteristics. In particular, when a device having a very large amount of heat generation per unit area, such as a laser chip having a high energy density, which has been difficult to cope with with conventional substrates, is mounted, a great effect can be exerted. According to the present invention, it is possible to obtain an element mounting device that has high heat dissipation characteristics and that operates the element stably for a long time. By utilizing the present invention, it is possible to obtain a semiconductor device which is excellent in heat dissipation and, in turn, has a significantly increased packaging density. As a result, a high-performance information processing device can be provided in a small size and at low cost.

[Brief description of drawings]

FIG. 1 is a plan view showing the concept of a grooved high thermal conductivity material layer in the present invention.

FIG. 2 is a front view of a substrate according to the present invention.

FIG. 3 is a plan view showing the concept of a grooved high thermal conductivity material layer in the present invention.

FIG. 4 Grooved AlN of Comparative Example 1 not included in the present invention
The top view which shows the concept of a layer.

FIG. 5 is a front view of a heat dissipation board using a grooved AlN layer in Comparative Example 1 which is not included in the present invention.

FIG. 6 is a side view showing the concept of a conventional heat dissipation board in Comparative Example 2 which is not included in the present invention.

FIG. 7 is a cross-sectional view showing a groove formed in the high thermal conductivity material layer according to the present invention.

FIG. 8: Raman spectra of diamond and non-diamond carbon.

FIG. 9 is a plan view of a substrate of the present invention in which a highly thermal conductive material surrounds the periphery of a flow channel.

FIG. 10 is a front view of the substrate of FIG.

FIG. 11 is a plan view of another substrate of the present invention in which the high thermal conductive material surrounds the flow path periphery.

FIG. 12 is a sectional view showing a flow channel formed in the substrate of the present invention.

FIG. 13 is a perspective view of a semiconductor device of the present invention.

14 is a sectional view of a part of the semiconductor device of FIG.

FIG. 15 is a plan view showing another substrate of the present invention in which a highly heat-conductive substance surrounds the periphery of a flow channel.

[Explanation of symbols]

11, 21, 41 ... High thermal conductivity material layer 31 ... AlN layer 12, 22, 32 ... Grooves for passing refrigerant 13, 33, 43 ... Base material 14, 34 ... Refrigerant inlet / outlet 15, 35, 45 ... Adhesive layer 16, 36, 46 ... Substrate 111, 121, 201, 221 ... Substrate 112, 122, 123, 222 ... Channels for passing refrigerant 113 ... First high thermal conductivity film 114 ... Second high thermal conductive film 115 ... Adhesive layer 116, 206 ... Refrigerant inlet / outlet 124 ... Refrigerant inlet 125 ... Refrigerant outlet 209 ... IC 210 ... Semiconductor device

─────────────────────────────────────────────────── ─── Continuation of front page (31) Priority claim number Japanese Patent Application No. 6-319978 (32) Priority date December 22, 1994 (December 22, 1994) (33) Priority claim country Japan (JP) (31) Priority claim number Japanese Patent Application No. 6-319982 (32) Priority date December 22, 1994 (December 22, 1994) (33) Priority claim country Japan (JP) (72) Inventor Naoji Fujimori 1-1-1 Kunyokita, Itami-shi, Hyogo Sumitomo Electric Industries, Ltd. Itami Works (56) References: 2-24588 (JP, U) Rameshham, Fabrication of Microchannels in Synthetic Polycrystalline Diamond Thin Films for Heat Sinking A pplc, J. Am. Electroch em. Soc. , June 1991, Volume 138, No. 6, p. 1706-1709 (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 23/373 H01L 23/473

Claims (17)

(57) [Claims] 1. A high thermal conductive substance layer having a thermal conductivity of 10 W / cm · K or more is disposed on a substrate, and only the high thermal conductive substance layer side of an interface portion of the substrate / high thermal conductive substance layer. Is equipped with a flow path for passing a cooling medium,
Board quality is characterized by Oh Rukoto a diamond. 2. The substrate according to claim 1 , wherein diamond is produced by a vapor phase synthesis method. 3. The depth of the flow path for passing the cooling medium is 50 μm or more, and 90% of the thickness of the high thermal conductive material layer.
The substrate according to claim 1, wherein: 4. The substrate according to claim 1, wherein the width of the flow path for passing the cooling medium is 20 μm or more and 10 mm or less. 5. The substrate according to claim 1, wherein the distance between the flow paths for passing the cooling medium is 20 μm or more and 10 mm or less. 6. A width of a flow path for passing a cooling medium.
The substrate according to claim 1, wherein the ratio of (a) to the interval (b) is 0.02 ≦ (a / b) ≦ 50. 7. A flow path for passing a cooling medium,
The substrate according to claim 1, wherein the substrate is spirally or radially arranged from the central portion to the outer peripheral portion of the substrate. 8. The substrate according to claim 1, wherein the surface of the flow path for passing the cooling medium is treated to improve the wettability with respect to the cooling medium. 9. A high thermal conductive material layer having a thermal conductivity of 10 W / cm · K or more is disposed on a base material, and only the high thermal conductive material layer side of the base material / high thermal conductive material layer interface portion. Is equipped with a flow path for passing a cooling medium,
Heat sink substrate that quality is characterized by Oh Rukoto a diamond. 10. A high thermal conductive material layer having a thermal conductivity of 10 W / cm · K or more is disposed on a base material, and only the high thermal conductive material layer side of the base material / high thermal conductive material layer interface portion. Is provided with a flow path for passing a cooling medium, and a heating element having a maximum heat generation density of 1 W / cm ² or more is mounted on the high thermal conductive material layer, and the high thermal conductive material is diamond. An element mounting device characterized by the above. 11. The device mounting apparatus of claim 1 0, characterized in that said heating element is a semiconductor element. 12. The device mounting apparatus of claim 1 1, wherein the semiconductor device is a semiconductor laser. 13. The device mounting apparatus of claim 1 1, wherein the semiconductor device is a microprocessor. 14. A plate made of a highly heat-conductive substance having a heat conductivity of 10 W / cm · K or more, in which one or more flow paths for allowing a cooling medium to pass through are embedded .
Board quality is characterized by Oh Rukoto a diamond. 15. A plate made of a highly heat-conductive substance having a heat conductivity of 10 W / cm · K or more, in which one or more flow paths for allowing a cooling medium to pass through are embedded, whereby a highly heat-conductive substance is obtained.
Heat sink substrate that quality is characterized by Oh Rukoto a diamond. 16. A substrate made of a highly heat-conductive substance having a thermal conductivity of 10 W / cm · K or more is embedded with one or more flow paths for allowing a cooling medium to pass therethrough, and has a maximum size on the substrate. An element mounting apparatus, wherein at least one heating element having a heat generation density of 1 W / cm ² or more is mounted , and the high thermal conductivity substance is diamond . 17. Two or more substrates in which one or more flow paths for passing a cooling medium are embedded in a substrate made of a highly heat-conductive substance having a thermal conductivity of 10 W / cm · K or more. stacked and, and the each of the substrates is equipped with a one or more elements, metal wiring for connecting between the elements are arranged on or in a substrate on the substrate, high thermal conductivity material
There semiconductor device according to claim Oh Rukoto a diamond.