JPS61146793A - substrate - Google Patents

Abstract

PURPOSE:To obtain the titled substrate whose base body is coated with the film of high-quality artificial diamond or artificial diamond-like carbon which resembles closely natural diamond by coating the base body having specified heat conductivity with a diamond film or a diamond-like carbon film. CONSTITUTION:A substrate is obtained by coating its base body with a diamond film or a diamond-like carbon film, and the surface part of the base body or the base body itself is formed of a substance having >=10w/(m.k) heat conductivity. The diamond-like carbon film is the film wherein diamond, graphite, and amorphous carbon are mixed. Besides, the base body is the material to be coated with the diamond film or the diamond-like carbon film. As the material having >=10w/(m.k) heat conductivity, silver [(lambda:420w/(m.k)], gold [lambda:290w/(m.k)], aluminum lambda:240w/(m.k)], beryllium oxide [lambda:250w/(m.k)], silicon carbide [lambda:270w/(m.k)], etc., are exemplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a substrate coated with a high quality artificial diamond film or diamond-like carbon film having properties similar to natural diamond. The problem] Diamond has the highest hardness and thermal conductivity among currently known substances, and also has extremely high elastic modulus, compressive strength, and electrical insulation properties, and is transparent and chemically insulated. is also a stable substance. Therefore, in order to take advantage of its excellent properties, we apply wear-resistant coatings to jigs and tools and protective films for solar cells.

Research is underway to develop applications for optical lenses or semiconductor heat sinks. However, natural diamonds are produced in small quantities and are extremely expensive, so they cannot be used as a material for industrial use.

For this reason, research on the production of synthetic diamonds is actively being conducted, but synthetic diamonds produced using conventional methods under high temperature and high pressure are also quite expensive, and their usefulness as industrial materials is limited. poor. Moreover, both natural diamonds and artificial diamonds are generally lumpy or granular in shape, and it is difficult to manufacture glands, so that the useful properties of diamond cannot be fully utilized.

For this reason, research has recently been actively conducted to produce diamonds even at low temperatures and low pressures, and moreover, to produce diamond films. There are four main methods:

That is, the first method is a vacuum evaporation method in which diamond powder is irradiated with a laser beam or an electron beam in a vacuum to heat and evaporate it, and the vapor is deposited on the surface of a substrate to form a diamond-like carbon film.

Second, a hydrocarbon such as ethylene or acetylene is introduced onto the heated surface of the substrate, and the thermal energy of the substrate surface thermally decomposes the hydrocarbon to generate active species, thereby depositing diamond on the surface of the substrate. The third method is plasma chemical vapor deposition method, in which hydrocarbons are decomposed in plasma to generate active species, and diamond is deposited on the substrate surface. This method includes an ion beam method in which positive ions containing carbon are generated from graphite, and these positive ions are focused and impinged on the surface of a substrate, thereby depositing diamond or diamond-like carbon on the surface of the substrate.

All of these four methods are industrially advantageous because they are carried out at low temperatures and low pressures; however, the diamond film or diamond-like carbon film formed on the surface of the substrate by these methods is of high quality. However, it has at least one of the drawbacks listed below.

In other words, these disadvantages are: ■Contains graphite and amorphous carbon, ■Relatively low hardness, ■Poor electrical insulation, ■Uneven film thickness, ■Slow diamond precipitation rate, and ■Membrane surface. Poor smoothness. Problems include: poor adhesion to the substrate and easy peeling, 1) easily turning black and opaque, and 2) being thermally unstable and converting into graphite at a temperature of, for example, 750C.

Such problems can be a fatal weakness, for example, when manufacturing wear-resistant jigs and tools using cemented carbide as a base and forming a diamond film on its surface, or when manufacturing semiconductor heat dissipation substrates. Configure.

Therefore, it must be said that manufacturing a diamond film that does not cause the above-mentioned disadvantages ① to ② will effectively demonstrate the inherent characteristics of diamond, and its industrial value is extremely large. Many.

[Purpose of the invention]

In response to the above-mentioned needs, the present invention aims to provide a substrate in which the substrate is coated with a diamond film or a diamond-like carbon film having properties similar to natural diamond.

[Summary of the invention]

As a result of intensive research to achieve the above object, the present inventors have found that in the four diamond film manufacturing methods described above, when the substrate or the surface portion of the substrate is made of a material with high thermal conductivity, the formed diamond film They also discovered that the properties of diamond-like carbon films are extremely good, and developed the substrate of the present invention.

That is, the substrate of the present invention is a substrate consisting of a base and a diamond film or diamond-like carbon film covering the base, and the surface portion of the base or the base itself has an IOW/(m@k) or more. It is characterized by being composed of a material having a thermal conductivity of .

First, the term ``diamond-like carbon film'' in the present invention refers to a film in which diamond and graphite or amorphous carbon are heated. Further, the term "substrate" as used in the present invention refers to a material to be coated with a diamond film or a diamond-like carbon film.

The most important feature of the present invention is that the substrate itself or the surface portion of the substrate is made of a material having a thermal conductivity (J) of 10 W/(m −'k ) or more. This value is 10
If it is less than W/(m-k), the object of the present invention will not be achieved.

As such a substance, for example, silver (λ: 420W/
(m-k) L gold (λ: 290W/(m-k) )
, aluminum (λ: 240W/ (m-k))
, copper (λ: 390W/(m@k)), molybdenum (λ:
140W/(m-k)).

Silicon (λ: 125W/(m-k)) (gold X alone like D; beryllium oxide (λ: zsow/(m-
k)), aluminum oxide (λ: 20W/ (m@
oxides such as k) ); silicon carbide (λ: 270W
/ (nll'k) ) v carbonization yJt') 1 (λ: 2
0W/(m-k)); aluminum nitride (λ: 100W/(m-k)) + nitride such as hexagonal boron nitride (λ: 60W/(m-k)); 5
An alloy such as US304 stainless steel (λ: 15W/(m-k)) can be mentioned.

In manufacturing the substrate of the present invention, the substrate itself is composed of each of the above-mentioned substances, and the above-mentioned four methods, namely, vacuum evaporation method, chemical vapor deposition method, plasma chemical vapor deposition method, The ion beam method may be applied.

In addition, the base body is not a round material but a heat conduction wheel with a power consumption of 10W/
(m-k) of other metals or various alloys, the above-mentioned 10
A substrate can be obtained by forming a layer of a material having a thermal conductivity of W/(m-k) or higher, and then forming a diamond film or a diamond-like carbon film using the four methods described above. In this case, the layer of the above substance can be formed on the surface of the substrate by, for example, a coating method or a thermal spraying method.

Chemical vapor deposition method, plating method, vacuum evaporation method, sputtering method,
A layer of the above-mentioned substance is formed by applying a known film-forming technique such as an ion-blating method, or the substrate is made of the above-mentioned metal and then oxidized.

A method of forming a layer of the above-mentioned oxide, nitride, or carbide on the surface by performing a treatment such as nitriding or carbonizing is applicable. At this time, if the thickness of the layer is too thin, pinholes etc. will occur in the layer, so the thickness is preferably 0.05 μm or more.

[Embodiments of the invention]

In this case, the substrate was made of quartz glass, and a 1 μm thick silver layer was formed thereon by vacuum evaporation.

Next, using a mixed gas of methane and hydrogen (volume ratio 1:50) as a reaction gas, thermal filament deposition, which is a type of chemical vapor deposition method, was performed under the conditions of a gas pressure of 25 Torr, a filament temperature of 1950 CI, and a reaction time of 5 hours. A diamond film with a thickness of 10 μm was formed on the silver layer by applying the method, and then a diamond film with a thickness of 10 μm was formed on the quartz glass.

A substrate having a three-layer structure of silver and diamond was manufactured.

This is referred to as Example 1.

A magnesium oxide plate was used as the substrate, and a 5 μm thick silver layer was formed thereon by sputtering.

Next, a mixed gas of methane and hydrogen (volume ratio 1:10) was used as the reaction gas, and the gas pressure was 0. I Torr.

A film with a thickness of 8 μm was deposited on the silver layer by plasma chemical vapor deposition using microwaves under conditions of a reaction time of 5 hours.
A substrate was manufactured by forming a diamond film of m. This is referred to as Example 2.

In the same manner as in Example 1, the surface of the quartz glass was coated with a thickness of 1
A silver layer of .mu.m was formed. Using methane as the reaction gas, under the conditions of a gas pressure of 0.01 Torr and a reaction time of 1 hour,
A substrate was manufactured by forming a diamond-like carbon film with a thickness of 10 μm on the silver layer using a hot cathode ion beam evaporation method. This is referred to as Example 3 @ For comparison, a 4 μm thick diamond film was directly formed on the surface of quartz glass under the same conditions as Example 1, and a substrate with a two-layer structure consisting of quartz glass and diamond was formed. was manufactured. This is referred to as Comparative Example 1.

As a second comparative example, a 4 μm thick diamond film was directly formed on the surface of a magnesium oxide plate under the same conditions as in Example 2 to produce a two-layered substrate consisting of a magnesium oxide plate and diamond. This is referred to as Comparative Example 2.

In addition, as a third comparative example, a substrate was manufactured by directly forming a diamond-like carbon film with a thickness of 8 μm on the surface of quartz glass under the same conditions as in Example 3. This is referred to as Comparative Example 3.

X-ray diffraction, electron diffraction, Raman spectra, and infrared absorption spectra for the diamond films or diamond-like carbon films of the above six types of substrates.

The energy loss spectrum was measured to determine its crystal form, and the electrical resistance, Guitzkaas hardness, graphitization temperature, film surface smoothness, and adhesion to the substrate were also measured and evaluated.

For the smoothness of the membrane surface, measure the maximum height (Rmax) using the method specified in JIS BO601, and if 1max is less than 1.0 μm, it is considered good, and Rmax is 1.0 fi.
If Rmax is 3.0 μm or more and less than 3.0 μm, it is normal.
A case of 0 μm or more was judged as defective. Regarding adhesion, the substrate was cut in the thickness direction, the cut surface was polished, and the ratio of exposed gaps between the film and the substrate (or silver layer) was evaluated. % is good, 10% or more and less than 50ts is fair, 50
% or more was determined to be defective.

The above results are collectively shown in Table 1. In addition, the table shows 6
The deposition growth rate of the film was also noted. For reference, the characteristics of natural diamonds are also listed.

Three substrates were manufactured in the same manner as in Examples 1 to 3, except that a gold layer was formed in place of the silver layer in Examples 1 to 3. The properties of these three diamond films or diamond-like carbon films were measured and the results are shown in Table 2.

Table 2 A polymethyl methacrylate plate was used as the substrate, and an aluminum layer with a thickness of 1 μm was formed thereon by vacuum vapor deposition. Next, under a vacuum of 10-' Torr, the diamond powder was evaporated by irradiating a focused laser beam with an output of 50 W to form a diamond-like carbon film with a thickness of 4 μm on the aluminum layer. .

A substrate with a three-layer structure of diamond-like carbon was manufactured. This is referred to as Example 7.

Without forming an aluminum layer on the polymethyl methacrylate plate, a diamond-like carbon film with a thickness of 4 μm was formed directly on the polymethyl methacrylate plate by the laser vapor deposition method described above, and two layers of polymethyl methacrylate and diamond-like carbon were formed. A layered substrate was manufactured. This is referred to as Comparative Example 4.

An aluminum layer with a thickness of xttm was formed on the zirconium oxide plate in the same manner as in Example 3, and then an aluminum layer with a thickness of 10 μm was formed by applying the ion beam evaporation method under the conditions of Example 30.
A substrate with a three-layer structure on which a diamond-like carbon film of m thickness was formed was manufactured. This is referred to as Example 8.

Table 3 shows the characteristics of each of these layers.

In the case shown in Table 3, the substrate was a magnesium oxide plate, and a 1 μm thick copper layer was formed thereon by vacuum evaporation.

Next, using a mixed gas of methane and hydrogen (volume ratio 1:50) as a reaction gas, a thermal filament, which is one of the methods of chemical vapor deposition, was formed under the conditions of a gas pressure of 30 Torr, a filament temperature of 2000 C, and a reaction time of 5 hours. A diamond film with a thickness of 10 μm was formed on the copper layer by applying the method, and a substrate having a three-layer structure of magnesium oxide, copper, and diamond was manufactured. This is referred to as Example 9.

For comparison, a diamond film with a thickness of 5 μm was directly formed on the surface of a magnesium oxide plate under the same conditions as in Example 9 to produce a substrate with a two-layer structure consisting of magnesium oxide and diamond. This is referred to as Comparative Example 5. The substrate was Pyrex glass, and a 5 μm thick copper layer was formed thereon by electron beam evaporation.

Next, a mixed gas of methane and hydrogen (volume ratio 1:10) was used as the reaction gas, and the gas pressure was 0. A substrate was manufactured by forming a diamond film with a thickness of 6 μm on the steel layer by applying plasma chemical vapor deposition using microwaves under conditions of I Tart and reaction time of 5 hours. Example 1
0. For comparison, a diamond film with a thickness of 4 μm was directly formed on the surface of Pyrex glass under the same conditions as in Example 10 to produce a substrate with a two-layer structure consisting of Pyrex glass and diamond. This is referred to as Comparative Example 6.

A copper layer having a thickness of 1 μm was formed on the surface of the magnesium oxide plate in the same manner as in Example 9. A diamond-like carbon film with a thickness of 8 μm was formed on the steel layer using hot cathode ion beam evaporation under conditions of methane as a reaction gas, gas pressure of 0.01 Torr, and reaction time of 1 hour. A substrate was manufactured using the following steps. This is referred to as Example 11.

For comparison, under the same conditions as Example 11,
A substrate was manufactured by directly forming a diamond-like carbon film with a thickness of 8 μm on the surface of a magnesium oxide plate. This is referred to as Comparative Example 7.

The characteristics of the diamond film or diamond-like carbon film of the above six types of substrates were measured and the results are shown in Table 4.

The base is made of quartz glass, and 50'l'or
In an argon atmosphere of r, a voltage of 32 V is applied to a current of 80
Plasma spraying was performed using molybdenum powder under 325 mesh under operating conditions of 0A, and a thickness of 100μ was applied to the substrate surface.
A molybdenum layer of m was formed.

After that, the surface roughness of the dimolybdenum layer was 1ma by mechanical polishing.
x was 3 μm.

Next, using a mixed gas of methane and hydrogen (volume ratio 1:10) as a reaction gas, plasma chemical vapor deposition using microwaves was performed under the conditions of gas pressure Q, 1'I'orr, and reaction time of 5 hours. A diamond film having a thickness of 8 μm was formed on the molybdenum layer by applying the method to obtain a substrate with a three-layer structure. This is referred to as Example 12.

For comparison, a diamond film with a thickness of 3 μm was directly formed on the surface of quartz glass under the same conditions as in this example.
A substrate with a layered structure was obtained. This is referred to as Comparative Example 8.

The characteristics of each diamond film obtained were measured, and the
Table Example 13 In the case of forming an aluminum nitride layer on the surface of a substrate A zirconium chloride plate was used as the substrate, and a 2 μm thick nitride layer was deposited on this by chemical vapor deposition using a mixed gas of aluminum chloride and ammonia. The reaction gas is a mixed gas of hydrogen and hydrogen (volume ratio 1:50), and the gas pressure is 30
Torr, filament temperature 2000 C, reaction time 5
The thermal filament method (a type of chemical vapor deposition method) was applied under the condition of 15 μm thickness on the aluminum nitride layer.
A diamond film of m thickness was formed. The obtained substrate having a 93-layer structure is referred to as Example 13.

For comparison, a diamond film with a thickness of 5 μm was formed directly on a zirconium oxide plate under the above conditions. The obtained two-layer structure substrate is referred to as Comparative Example 9.

The characteristics of each diamond film were measured and the results are shown in Table 6.

Table 6 A magnesium oxide plate was used as the substrate, and a 3 μm thick silicon carbide layer was formed thereon by chemical vapor deposition using a mixed gas of silicon tetrachloride and propane gas (temperature: about 14001:1'). Then, under a vacuum of s 10 Torr, the diamond powder was irradiated with a focused laser beam with an output of 60 W to vaporize it, thereby forming a diamond-like carbon film with a thickness of 4 μm on the silicon carbide layer. Obtained 3
Example 14 was a substrate with a layered structure.

For comparison, a 4 μm thick diamond-like carbon film was formed on a magnesium oxide plate under the same conditions as above without forming a silicon carbide layer, and the resulting two-layer structure substrate was designated as Comparative Example 10.

The characteristics of the diamond-like carbon film of each substrate were measured and the results are shown in Table 7.

Table 7 Example 15 When a copper plate was used as the substrate A mixed gas of methane and hydrogen (volume ratio 1:50) was used as the reaction gas, under the conditions of a gas pressure of 30 Torr, a filament temperature of 2000 C, and a reaction time of 5 hours. Applying the hot filament method, which is a type of chemical vapor deposition method, the film is deposited directly on the copper plate to a thickness of 10 μm.
A diamond film of m thickness was formed to produce a substrate with a two-layer structure consisting of copper and diamond. This is referred to as Example 15. For comparison, a 5 μm thick diamond film was directly formed on the surface of quartz glass under the same conditions as Example 15.
A two-layer structure substrate made of quartz glass and diamond was manufactured. This is referred to as Comparative Example 11.

The characteristics of each diamond film obtained were measured and the results are shown in Table 8.

When Table 8 is used, a mixed gas of methane and hydrogen (volume ratio 1:10) is used as the reaction gas, and the gas pressure is 0. Under the conditions of I Torr and reaction time of 5 hours, a diamond film with a thickness of 8 μm was formed directly on the molybdenum plate by applying plasma chemical vapor deposition using microwaves. A substrate for the structure was manufactured. This is referred to as Example 16.

For comparison, a 4 μm thick diamond film was directly formed on the surface of a magnesium oxide plate under the same conditions as in Example 16 to produce a substrate with a two-layer structure consisting of magnesium oxide and diamond.

This is referred to as Comparative Example 12.

The characteristics of each diamond film obtained were measured and the results are shown in Table 9.

Table 9 Example 17 When a silicon carbide plate is used as the substrate Diamond powder is irradiated with a convergent laser beam with an output of 55 W under a vacuum of I
A diamond-like carbon film with a thickness of 4 μm was directly formed on a silicon carbide plate to produce a substrate with a two-layer structure consisting of silicon carbide and a diamond-like carbon film. Example 17
shall be.

For comparison, a diamond-like carbon film with a thickness of 4 μm was directly formed on the surface of a polymethyl methacrylate plate under the same conditions as in Example 17, and a two-layer structure consisting of polymethyl methacrylate and a diamond-like carbon film was obtained. A board was manufactured.

This is referred to as Comparative Example 13.

The characteristics of each diamond film obtained were measured and the results are shown in Table 1θ.

Table 10 [Effects of the Invention] As is clear from the above description, the diamond powder or diamond-like carbon film constituting the surface coating layer of the substrate of the present invention has a certain crystal shape and electrical resistance.

Properties such as hardness are similar to those of natural diamond, and the surface smoothness of the film is excellent.
It has good adhesion to the substrate or to the layers of the various substances on the surface of the substrate, and is a substrate that makes effective use of the useful properties of diamond.

Therefore, the substrate of the present invention is expected to be used as a heat sink for jigs and tools and semiconductors, and has great industrial value.

Claims (1)

[Claims] A substrate consisting of a base and a diamond film or diamond-like carbon film covering the base, wherein the surface portion of the base or the base itself has a power of 10 W/(m·
k) A substrate characterized in that it is made of a substance having a thermal conductivity higher than or equal to above.