GB2228745A - Process for the selective deposition of thin diamond film gas phase synthesis - Google Patents

Process for the selective deposition of thin diamond film gas phase synthesis Download PDF

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Publication number
GB2228745A
GB2228745A GB9000473A GB9000473A GB2228745A GB 2228745 A GB2228745 A GB 2228745A GB 9000473 A GB9000473 A GB 9000473A GB 9000473 A GB9000473 A GB 9000473A GB 2228745 A GB2228745 A GB 2228745A
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diamond
gas phase
phase synthesis
areas
thin
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GB9000473D0 (en
GB2228745B (en
Inventor
Takayoshi Inoue
Hiroyuki Tachibana
Akimitsu Nakaue
Kazuo Kumagai
Koichi Miyata
Koji Kobashi
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Kobe Steel Ltd
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Kobe Steel Ltd
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Priority claimed from JP409289A external-priority patent/JPH02184598A/en
Priority claimed from JP32225989A external-priority patent/JP2690796B2/en
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    • H—ELECTRICITY
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    • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
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    • H01L21/02115—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material being carbon, e.g. alpha-C, diamond or hydrogen doped carbon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/04—Coating on selected surface areas, e.g. using masks
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/04—Coating on selected surface areas, e.g. using masks
    • C23C16/042—Coating on selected surface areas, e.g. using masks using masks
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/26—Deposition of carbon only
    • C23C16/27—Diamond only
    • C23C16/274—Diamond only using microwave discharges
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
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    • H01L21/0226—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
    • H01L21/02263—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase
    • H01L21/02271—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition
    • H01L21/02274—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition in the presence of a plasma [PECVD]
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    • H01L21/02636—Selective deposition, e.g. simultaneous growth of mono- and non-monocrystalline semiconductor materials
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    • H01L21/02636—Selective deposition, e.g. simultaneous growth of mono- and non-monocrystalline semiconductor materials
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    • H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
    • H01L21/02123—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon
    • H01L21/02164—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material being a silicon oxide, e.g. SiO2
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    • H01L21/0217—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz

Abstract

Thin diamond films are selectively deposited imagewise on a substrate by gas phase synthesis. The substrate may be either a silicon substrate or a basal thin diamond film formed beforehand on a substrate by gas phase synthesis. Where a silicon substrate is used, its surface is i) first abraded to give a surfaee roughness suitable for gas phase synthesis of diamond followed by ii) coating a uniform photoresist layer; iii) exposing the photoresist layer imagewise to illumination; iv) developing the thus-exposed photoresist layer, whereby exposed areas and unexposed areas are distinguished from each ether and the photoresist layer is eliminated in the exposed or unexposed areas; v) subjecting the surface of the silicon substrate in the areas, from which the photoresist layer has been eliminated, to reactive ion etching by a gas mixture discharge of CF4, Ar and O2; vi) dissolving any remaining photoresist layers; and vii) carrying out gas phase synthesis of diamond. When a basal thin diamond film is used, a coating material having a withstandable temperature higher than a substrate temperature required for gas phase synthesis of diamond and having a high etching selectivity to diamond eg amorpheus silicon is needed to cover areas other than areas where new thin diamond film is to be formed. In this embodiment the suriace is coated with a photoresist lithography, amorphous silicon is deposited over entire surfaces, the photoresist layer is lifted thereby producing a coating of silicon in those areas ether than where diamond is to be formed, and diamond is thereafter deposited in the gaps and the silicon depositss are removed. In a further embodiment a thin masking film having a melting point higher than a temperature to be employed for gas phase synthesis of diamond, eg amorphous silicon again, can be used to partly mask the surface of a basal diamond film by first applying the silicon over the entire surface, covering this layer with a photoresist layer by lithography in areas corresponding to where diamond is not to be deposited, eliminating the silicon in the areas not covered by the photoresist, producing a patterned silicon layer and depositing diamond in a pattern conforming with the intended surface areas of the basal thin diamond film. The silicon layer may then be removed. The coated products will find use as heat sinks, insulators in integrated circuits, semiconductor devices and optical waveguides.

Description

TITLE OF THE INVENTION: PROCESS FOR THE SELECTIVE DEPOSITION OF THIN DIAMOND FILM BY GAS PHASE SYNTHESIS BACKGROUND OF THE INVENTION a) Field of the Invention: The present invention relates to a process for the selective deposition of thin diamond films by gas phase synthesis, and specifically to a process for selectively growing by gas phase synthesis thin diamond films on desired areas of a silicon substrate or on desired areas of a surface of a basal thin diamond film formed beforehand on a desired substrate by gas phase synthesis. This process is useful for the development of new devices and materials in the semiconductor field, the up-to date electronic fields; and the like.
b) Description of the Related Art: It has been known that a thin diamond film can be formed on a substrate by gas phase synthesis, namely, by using as a raw material a gas mixture of a hydrocarbon gas, such as methane, and a hydrogen gas, and by subjecting it to cracking or plasma reaction in a vacuum chamber. A variety of processes have been proposed to practice this technique. It has now been recognized by identification characterization of various properties such as crystallinity, the directionality of crystalline growth and thermal conductivity that various thin diamond films so formed by gas phase synthesis have properties identical to natural diamond.
As potential application fields making use of such properties of thin diamond films formed by gas phase synthesis, various attempts have heretofore been made to use them as abrasive coatings for cemented carbide (WC) tools, heat sinks for ICs, coatings for speaker diaphragms and so on. In such applications, it is required to deposit thin diamond films uniformly on substrates or base materials. Accordingly, selective deposition has not been attempted at all.
As an application field of the thin film technology, there is the semiconductor field. This field is considered to have the greatest future prospect and development as an application field of thin diamond films. Current semiconductors are mainly Si semiconductors which employ a silicon wafer as a substrate. If it becomes feasible to form a thin diamond film on a silicon wafer and further to form the thin diamond film as a fine pattern on the order of micrometers by selective deposition, it will be possible to use thin diamond films as heat sinks for certain specific elements of integrated circuits, insulators between circuit wirings in integrated circuits, high performance devices fabricated by hybridization of Si and thin diamond semiconductor films, optical waveguides using thin diamond films, and the like.
Under the current level of technology for depositing a thin diamond film on a silicon substrate, it is essential as shown in FIGS. 4(a) to 4(c) to abrade a surface of a silicon wafer 1 with diamond powder or paste of a particle size on the order of several micrometers to provide an abraded wafer 1' having a number of scratches 21 in the surface and then to deposit a thin diamond film 22 thereon by gas phase synthesis. Owing to the existence of the surface scratches 21, the diamond nucleation density is increased substantially so that the thin diamond film 22 can be obtained as a continuous polycrystalline thin diamond film. If the above abrasion were not applied, no diamond would practically be formed on the silicon wafer.On the contrary, the abrasion results in uniform formation of diamond particles on the surface of the silicon wafer, whereby diamond eventually grows into a continuous film. It is therefore impossible to form a circuit or pattern, which has a desired configuration, with a thin diamond film.
As is known very well, diamond has the highest hardness among ail the materials and also has a high thermal conductivity and excellent heat resistance and radiation resistance. Using gas-phase-synthesized diamond, the development of environment-resistant electronic devices, semiconductor devices and the like, which are equipped with such attractive properties, are now under way.
For the application of gas-phase-synthesized diamond in the field of such electronic technology, there has been an outstanding demand for the development of a technique for permitting selective formation or deposition of thin diamond films on desired areas of a surface of silicon substrate or wafer. With a view toward meeting this demand, the present assignee has proposed the following process for the gas phase synthesis of diamond (Japanese Patent Application Laid Open No. 297298/1987).
Namely, prior to gas phase synthesis of diamond on a silicon substrate, desired areas of a surface of the substrate, on which diamond is to be deposited, are selectively covered with a masking material. The remaining areas other than those covered with the masking material are coated with an amorphous material such as amorphous silicon. The masking material is then stripped off to expose the surface of the substrate, followed by the application of gas phase synthesis thereby to deposit a thin diamond film on the thus-exposed surface areas of the substrate.
Since the above technique has made it possible to form a thin diamond film on the surface of a silicon substrate in accordance with a desired pattern, trial fabrication of diamond semiconductors and the like has been further facilitated.
The above technique has however been found to involve such problems that when a silicon substrate is used as a basal substrate, the maximum breakdown voltage of the resulting device is governed by silicon as the basal substrate and the device is prone to damages due to the difference in thermal expansion coefficient between silicon and diamond when used at elevated temperatures.
If a technique can be established to permit the deposition of an additional thin diamond film in accordance with a desired pattern by gas phase synthesis on a surface of a basal thin diamond film formed beforehand on a silicon substrate by gas phase synthesis, the above-described problems can be solved by etching off the silicon substrate alone, if necessary, after forming a semiconducting device on the basis of such a technique.
SUMMARY OF THE INVENTION An object of this invention is to provide a solution to the problem that the conventional processes cannot selectively deposit a thin diamond film on the order of micrometers in the form of a pattern or circuit although they can uniformly deposit a thin diamond film on a silicon substrate or another base material.
Another object of this invention is to provide a process for the selective deposition of thin diamond films by gas phase synthesis, which permits the deposition of a new thin diamond film in accordance with a desired pattern by gas phase synthesis on a surface of a basal thin diamond film formed beforehand on a desired substrate by gas phase synthesis.
In a first aspect of this invention, there is thus provided a process for the selective imagewise deposition of thin diamond films on a silicon substrate by gas phase synthesis, which comprises: i) abrading a surface of the silicon substrate to give scratches suitable for gas phase synthesis of diamond thereon; ii) coating a uniform photoresist layer on the thusabraded surface; iii) exposing the photoresist layer imagewise to radiation; iv) developing the thus-exposed photoresist layer, whereby exposed areas and unexposed areas are distinguished from each other and the photoresist layer is eliminated at the exposed or unexposed areas; v) subjecting the surface of the silicon substrate at the areas where the photoresist layer has been eliminated, to reactive ion etching by a gas mixture discharge of CF4, Ar and 02; vi) washing off any remaining photoresist layer; and vii) carrying out gas phase synthesis of diamond by using the silicon substrate processed through the preceding steps i) to vi).
According to the above process of the invention, the surface abraded in step i) is exposed in step vi) only in the form of a circuit, a pattern or the like baked in the photoresist in step iv). A thin diamond film is deposited on the thus-exposed surface areas in step vii), so that the circuit, pattern or the like can be formed on the order of micrometers.
Further, the reactive ion etching (RIE) of the silicon substrate by the gas mixture discharge of CF4, Ar and O2 in step v) permits the deposition of a thin diamond film in the desired pattern with good selectivity.
In a second aspect of this invention, there is also provided a process for the selective imagewise deposition of new thin diamond films by gas phase synthesis on a surface of a basal thin diamond film formed beforehand on a substrate by gas phase synthesis, which comprises: i) coating predetermined areas of the surface of the basal thin diamond film, said predetermined areas being other than specific areas where the newly-grown thin diamond film is to be formed, with a material having a withstandable temperature higher than a substrate temperature required for gas phase synthesis of diamond and having a high etching selectivity to diamond; and ii) carrying out gas phase synthesis of diamond so as to form thin diamond films on the specific areas of the basal thin diamond film.
In a third aspect of this invention, there is also provided a process for the selective imagewise deposition of new thin diamond films by gas phase synthesis on a surface of a basal diamond film formed beforehand on a non-diamond substrate, which comprises: i) partly masking the surface of the basal diamond films with thin masking films having a melting point higher than a temperature to be employed for gas phase synthesis of diamond; and ii) depositing diamond on unmasked areas of the surface of the basal diamond film by gas phase synthesis.
In the processes of the second and third aspects of the invention for the selective deposition of a thin diamond film by gas phase synthesis, the chances for the nucleation of diamond particles are extremely low at the areas covered or masked with the material having a withstandable temperature higher than the substrate temperature required for gas phase synthesis of diamond and having a high etching selectivity to diamond or with the thin masking film having a melting point higher than a temperature to be employed for gas phase synthesis of diamond, in other words, in the areas where the deposition of a new thin diamond film is not desired, so that the deposition of a thin diamond film is highly inhibited there. This allows to deposit new thin diamond films in desired areas on the surface of the basal thin diamond film.Even if diamonds are slightly formed on the surface of the coating or masking films of the above-described material, the bonding of the diamond is extremely weak so that the diamond can be easily removed. Thus, such diamonds do not give any inconvenience for the achievement of the objects of the invention.
According to the processes of the second and third aspects of the invention, new thin diamond films can be deposited at desired areas on the surface of a basal thin diamond film in accordance with the pattern of the desired areas.
Removal of only a silicon or like substrate, if necessary, after the fabrication of semiconducting devices in accordance with any of the above-described selective deposition processes of this invention allows the device to have excellent characteristics of diamond itself. The present invention can therefore contribute to the development of electronic devices, equipped with the excellent performance that their maximum breakdown voltages have been improved significantly and the devices are free from the potential problem of damages at elevated temperatures due to the difference in thermal expansion coefficients.
BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the appended drawings, in which: FIGS. l(a) to l(g) schematically illustrates various steps of a first example of the process according to the invention and partly fabricated products, in the order of the steps which are carried out as indicated by arrows; FIGS. 2(a) to 2(e) schematically depicts various steps of a second example of the process according to the invention and partly fabricated products, in the order of the steps which are conducted as indicated by arrows;; FIGS. 3(a) to 3(e) schematically shows various steps of a third example of the process according to the invention and partly fabricated products, in the order of the steps which are conducted as indicated by arrows; FIGS. 4(a) to 4(c) schematically shows various steps of a conventional process for the deposition of diamond on a silicon wafer by gas phase synthesis, which proceed as indicated by arrows.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS The material for coating the areas, in which deposition of new thin diamond films are not desired, in the process according to the second embodiment of this invention has, as described above, the properties that it can suppress nucleation of diamond particles and it has a high etching selectivity to diamond. The term "high etching selectivity to diamond" as used herein means that upon eliminating of the coating material subsequent to the deposition of new thin diamond films on the basal thin diamond film, diamond is not adversely affected, for example, it is not dissolved by a reagent, gas or the like to be employed to eliminate or otherwise remove the coating material. The coating material is required to have a withstandable temperature higher than the substrate temperature needed for the gas phase synthesis of diamond. This requirement is to prevent any deformation of the coating film, which is supposed to define the shape or pattern of thin diamond films to be deposited newly, when the substrate is heated upon formation of diamond by gas phase synthesis.
Incidentally, in the gas phase synthesis of diamond, for example, by a microwave plasma CVD process, the gas phase synthesis of diamond is conducted by maintaining the substrate temperature around 800 OC.
Exemplary materials equipped with such properties include amorphous ceramics such as amorphous silicon, silicon oxide and silicon nitride, microcrystalline silicon, and the like. Of these, amorphous silicon is preferred from the standpoint of easiness in coating.
In the process according to the second aspect of the invention, new thin diamond films are grown with a greater grain size compared with the basal thin diamond film. The thin diamond film as the basal layer is formed, for example, on a silicon substrate whose surface has been buffed with a diamond paste, so that the initial nucleation density is high and crystal grains are small in the initial stage of the growth. As diamond crystals grow, they mutually undergo competitive growth so that the crystal density decreases and crystal grains become greater. On the other hand, new thin diamond films grow epitaxialy on the basal thin diamond film, so that the newly-grown thin diamond films have large crystal grains. Although the controllability is poor, it is desired to use a fast film-forming process upon gas phase synthesis of the basal thin diamond film.
When new thin diamond films are overlayed on the basal thin diamond film by gas phase synthesis, new thin diamond films may be allowed to slowly grow with good controllability because a large thickness is usually not needed for new thin diamond films.
The following specific examples are presented to illustrate a few embodiments of the invention, but it is to be understood that the invention is not limited thereto.
Example 1: One embodiment of the process of the present invention will hereinafter be described with reference to FIGS. l(a) to l(g).
In step i), one side of a 20 x 10 mm silicon wafer of n-type Si(lll) by way of example is buffed for 1 hour with a diamond paste having a grain size of 1/4 pm, thereby forming an abraded surface la [ FIG. l(a) ] .
In step ii), a positive photoresist film 2 is formed on the abraded surface la of the thus-buffed silicon wafer 1 by means of a spinner 23 [ FIG. l(b) ] .
The silicon wafer 1 thus coated is next subjected to pre-baking to evaporate an organic solvent from the photoresist film 2.
In step iii), the photoresist film 2 is exposed to ultraviolet rays 4 through a photomask 3 which bears a circuit or a pattern. Exposed resist portions 2a are sensitized and softened [FIG. l(c) ] .
In step iv), the softened resist portions 2a are eliminated with a developer, whereby unexposed resist portions 2b remain on the silicon wafer 1 [FIG.
l(d) ] * Post-baking is next conducted to solidify the remaining resist portions 2b.
In step v), the exposed portions of the abraded surface la of the silicon wafer 1, said exposed portions being not covered with the resist portions 2b, are subjected to etching in an unillustrated plasma etching apparatus, thereby forming etched surface portions lb [FIG. l(e) ] . A mixed gas of CF4, O2 and Ar is used as a reaction gas.
In step vi), the remaining resist portions 2b are eliminated by a mixed solution of sulfuric acid and hydrogen peroxide. As a result, remaining abraded surface portions lc other than the etched surfaces portions lb are exposed in a form conforming with the circuit or pattern referred to above [FIG. l(f) ] .
In step vii), using an unillustrated gas phase diamond deposition apparatus (microwave plasma CVD apparatus, hot filament CVD apparatus or the like), gas phase synthesis of diamond is carried out on the silicon wafer substrate [FIG. l(g) ] . When a microwave plasma CVD apparatus is used, the gas phase synthesis can be carried out using a 1.0% CH4 concentration, 31.5 Torr gas pressure and 8000C substrate temperature. It takes about 3.5 hours until new thin diamond films are deposited to a desired thickness.
As schematically depicted in FIG. l(g), diamond is allowed to selectively grow only on the abraded portions lc in the form of the circuit or pattern so that the desired pattern of thin diamond films (5) are formed.
Example 2: Another embodiment of the process of the present invention will next be described with reference to FIG. 2(a) to 2(e). One side of a silicon substrate 1 of desired dimensions is buffed beforehand with a diamond paste. Using a microwave plasma CVD apparatus, a basal thin diamond film 6 is formed as an undercoat to a thickness of 5 pm. The present embodiment will hereinafter be described in the order of the steps thereof.
(1) First, surface areas 6a of the basal thin diamond film 6, where diamond is to be formed newly, are coated with photoresist layers 2 to a thickness of about 1 pm by a known lithographic technique [FIG. 2(a) ] .
(2) Next, amorphous silicon 7 is deposited over the entire surfaces of the basal thin diamond film 6 and photoresist layers 2 as shown in FIG. 2(b).
(3) The photoresist layers 2 are lifted. At this time, the amorphous silicon 7 deposited on the photoresist layers 2 are also removed. As a result, coating layers 7a made of the amorphous silicon 7 are formed on the basal thin diamond film 6 in the surface areas 6b other than the surface areas 6a where diamonds are to be formed newly [ FIG. 2(c) ] .
(4) Using a microwave plasma CVD apparatus, gas phase synthesis is thereafter conducted for 7 hours while maintaining the silicon substrate 1 at about 8000C. As a result, without deformation of the coating layers 7a, thin diamond films 5 of 1.5 pm thick are formed in a pattern conforming with the intended surface portions 6a on the basal thin diamond film 6 [FIG.
2(d)]. Thereafter, as shown in FIG. 2(e), the coating layers 7a are eliminated by an aqueous solution of fluoronitric acid.
Example 3: A further embodiment of the process of the present invention will now be described with reference to FIG. 3(a) to 3(e). Similarly to the embodiment of Example 2, a basal thin diamond film 6 is deposited beforehand to a thickness of 5 pm on a silicon substrate 1. The present embodiment will hereinafter be described in the order of the steps thereof.
(1) After forming a coating layer 14 of amorphous Si to a thickness of several hundreds angstroms over the entire upper surface of the basal thin diamond film 6, the coating layer 14 is covered with photoresist layers 2 by a lithographic technique in the areas corresponding to surface portions 6b of the basal thin diamond layer 6, said surface portions 6b being other than surface portions 6a where diamonds are to be deposited newly [FIG. 3(a)].
(2) Next, the coating layers 14 are eliminated in the areas not covered by the photoresist layers 2, that is, at the surface portions 6a where diamonds are to be deposited newly [FIG. 3(b)].
(3) The photoresist layers 2 are eliminated.
As a consequence, the coating layers 14 made of amorphous silicon are formed in the surface areas 6b of the basal thin diamond film 6, said surface areas 6b being other than the surface areas 6a where diamonds are to be formed newly [FIG. 3(c) ] .
(4) Next, similarly to the embodiment of Example 2, gas phase synthesis of diamond is conducted using a microwave plasma CVD apparatus. As a result, thin diamond films 5 of 1.5 pm thick are formed in a pattern conforming with the intended surface areas 6a of the basal thin diamond film 6 [FIG. 3(d)]. Thereafter, it is only necessary to eliminate the coating layers 14 by an aqueous solution of fluoronitric acid.
In Examples 2 and 3 amorphous silicon is used as an amorphous material. An amorphous ceramic such as silicon oxide or silicon nitride as well as microcrystalline silicon can also be used instead.

Claims (7)

CLAIMS:
1. A process for the selective imagewise deposition of thin diamond films on a silicon substrate by gas phase synthesis, which comprises: i) abrading a surface of the silicon substrate to give a surface roughness suitable for gas phase synthesis of diamond thereon; ii) coating a uniform photoresist layer on the thus-abraded surface; iii) exposing the photoresist layer imagewise to illumination; iv) developing the thus-exposed photoresist layer, whereby exposed areas and unexposed areas are distinguished from each other and the photoresist layer is eliminated in the exposed or unexposed areas; v) subjecting the surface of the silicon substrate in the areas, where from which the photoresist layer has been eliminated, to reactive ion etching by a gas mixture discharge of CF4, Ar and Oz; vi) dissolving any remaining photoresist layers; and vii) carrying out gas phase synthesis of diamond by using the silicon substrate processed through the preceding steps i) to vi).
2. The process of claim 1, wherein the uniform photoresist layer is applied on a spinner.
3. The process of claim 1, wherein the exposure is conducted using a photomask.
4. A process for the selective imagewise deposition of new thin diamond films by gas phase synthesis on a surface of a basal thin diamond film formed beforehand on a substrate by gas phase synthesis, which comprises: i) coating predetermined areas of the surface of the basal thin diamond film, said predetermined areas being other than specific areas where new thin diamond films are to be formed, with a material having a withstandable temperature higher than the substrate temperature required for gas phase synthesis of diamond and having a high etching selectivity to diamond; and ii) carrying out gas phase synthesis of diamond so as to form a thin diamond film on the specific areas of the basal thin diamond film.
5. A process for the selective imagewise deposition of new thin diamond films by gas phase synthesis on a surface of a basal diamond film formed beforehand on a non-diamond substrate, which comprises: i) partly masking the surface of the basal diamond film with a thin masking film having a melting point higher-than a temperature to be employed for gas phase synthesis of diamond; and ii) depositing diamond films on unmasked areas of the surface of the basal diamond film by gas phase synthesis.
6. The process of claim 5, wherein the thin masking film is formed of amorphous silicon.
7. A process substantially as herein described with reference to the Examples and as illustrated in the accompanying Figures.
GB9000473A 1989-01-10 1990-01-09 Process for the selective deposition of thin diamond film by gas phase synthesis Expired - Fee Related GB2228745B (en)

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JP409289A JPH02184598A (en) 1989-01-10 1989-01-10 Selective film formation of diamond through vapor synthesis
JP32225989A JP2690796B2 (en) 1989-12-11 1989-12-11 Selective formation method of vapor phase synthetic diamond thin film

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Cited By (9)

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GB2253416A (en) * 1991-02-21 1992-09-09 De Beers Ind Diamond Radiation absorber comprising a CVD diamond film having special surface characteristics
FR2675947A1 (en) * 1991-04-23 1992-10-30 France Telecom PROCESS FOR LOCAL PASSIVATION OF A SUBSTRATE BY A HYDROGEN AMORPHOUS CARBON LAYER AND METHOD FOR MANUFACTURING THIN FILM TRANSISTORS ON THE PASSIVE SUBSTRATE.
EP0528592A1 (en) * 1991-08-08 1993-02-24 General Electric Company Method for selective CVD diamond deposition
GB2263709A (en) * 1992-01-28 1993-08-04 Ngk Spark Plug Co Method for producing silicon nitride based members coated with synthetic diamond
EP0674181A2 (en) * 1994-03-24 1995-09-27 Sumitomo Electric Industries, Ltd. Micro mechanical component and production process thereof
GB2309979A (en) * 1995-06-29 1997-08-13 Diamanx Products Ltd Diamond treatment
DE19649409A1 (en) * 1996-04-12 1997-10-16 Lg Semicon Co Ltd Diamond film fine processing method
EP0882812A1 (en) * 1997-06-02 1998-12-09 Japan Energy Corporation Method of manufacturing member for thin-film formation apparatus and the member for the apparatus
EP3211657A3 (en) * 2016-02-29 2017-11-15 Shin-Etsu Chemical Co., Ltd. Method for manufacturing diamond substrate, diamond substrate, and freestanding diamond substrate

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Publication number Priority date Publication date Assignee Title
CN103890945B (en) * 2011-10-28 2017-05-10 惠普发展公司，有限责任合伙企业 Devices including a diamond layer

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JPS62297298A (en) * 1986-06-16 1987-12-24 Kobe Steel Ltd Vapor-phase synthesis of diamond

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JPS62297298A (en) * 1986-06-16 1987-12-24 Kobe Steel Ltd Vapor-phase synthesis of diamond

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2253416A (en) * 1991-02-21 1992-09-09 De Beers Ind Diamond Radiation absorber comprising a CVD diamond film having special surface characteristics
FR2675947A1 (en) * 1991-04-23 1992-10-30 France Telecom PROCESS FOR LOCAL PASSIVATION OF A SUBSTRATE BY A HYDROGEN AMORPHOUS CARBON LAYER AND METHOD FOR MANUFACTURING THIN FILM TRANSISTORS ON THE PASSIVE SUBSTRATE.
US5250451A (en) * 1991-04-23 1993-10-05 France Telecom Etablissement Autonome De Droit Public Process for the production of thin film transistors
EP0528592A1 (en) * 1991-08-08 1993-02-24 General Electric Company Method for selective CVD diamond deposition
US5626908A (en) * 1992-01-28 1997-05-06 Ngk Spark Plug Co., Ltd. Method for producing silicon nitride based member coated with film of diamond
GB2263709A (en) * 1992-01-28 1993-08-04 Ngk Spark Plug Co Method for producing silicon nitride based members coated with synthetic diamond
GB2263709B (en) * 1992-01-28 1994-09-28 Ngk Spark Plug Co Method for producing silicon nitride based members with synthetic diamond
EP0674181A2 (en) * 1994-03-24 1995-09-27 Sumitomo Electric Industries, Ltd. Micro mechanical component and production process thereof
EP0674181A3 (en) * 1994-03-24 1997-02-05 Sumitomo Electric Industries Micro mechanical component and production process thereof.
US5729074A (en) * 1994-03-24 1998-03-17 Sumitomo Electric Industries, Ltd. Micro mechanical component and production process thereof
EP1271155A1 (en) * 1994-03-24 2003-01-02 Sumitomo Electric Industries, Ltd. Micromechanical component comprising a diamond layer, and production process
GB2309979A (en) * 1995-06-29 1997-08-13 Diamanx Products Ltd Diamond treatment
US5916456A (en) * 1995-06-29 1999-06-29 Diamanx Products Limited Diamond treatment for passivating stress surface defects
GB2309979B (en) * 1995-06-29 1999-01-27 Diamanx Products Ltd Diamond treatment
DE19649409A1 (en) * 1996-04-12 1997-10-16 Lg Semicon Co Ltd Diamond film fine processing method
DE19649409B4 (en) * 1996-04-12 2005-10-13 LG Semicon Co., Ltd., Cheongju Method for producing a diamond film on a substrate
US6045665A (en) * 1997-06-02 2000-04-04 Japan Energy Corporation Method of manufacturing member for thin-film formation apparatus and the member for the apparatus
US6319419B1 (en) 1997-06-02 2001-11-20 Japan Energy Corporation Method of manufacturing member for thin-film formation apparatus and the member for the apparatus
EP0882812A1 (en) * 1997-06-02 1998-12-09 Japan Energy Corporation Method of manufacturing member for thin-film formation apparatus and the member for the apparatus
EP3211657A3 (en) * 2016-02-29 2017-11-15 Shin-Etsu Chemical Co., Ltd. Method for manufacturing diamond substrate, diamond substrate, and freestanding diamond substrate
US10253426B2 (en) 2016-02-29 2019-04-09 Shin-Etsu Chemical Co., Ltd. Method for manufacturing diamond substrate
US11066757B2 (en) 2016-02-29 2021-07-20 Shin-Etsu Chemical Co., Ltd. Diamond substrate and freestanding diamond substrate

Also Published As

Publication number Publication date
GB2260341A (en) 1993-04-14
GB9224174D0 (en) 1993-01-06
GB2260341B (en) 1993-09-08
GB2260342A (en) 1993-04-14
GB9000473D0 (en) 1990-03-07
GB2260342B (en) 1993-09-08
GB9224173D0 (en) 1993-01-06
GB2228745B (en) 1993-09-08

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