JPH0741388A - Method for flattening and polishing diamond - Google Patents

Abstract

PURPOSE:To favorably polish or flatten the surface of a diamond regardless of the state of a substrate by making the grinding speed of the protrusion of the diamond surface relatively higher than that of the recess of the diamond surface. CONSTITUTION:When the surface of a diamond is flattened by a dry process, the grinding speed of the protrusion of the diamond surface is made relatively higher than that of the recess of the diamond surface. In this method, a compressive stress is applied on the recess, if necessary, to reduce the recess grinding speed. In this case, a sacrifice layer contg. a specified amt. of impurities is used, the protrusion of the diamond surface is exposed and annealed, and then the impurities are incorporated into the recess. Boron is preferably used as the impurity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to polishing or flattening of single crystal diamond or polycrystalline diamond, and is particularly applicable to cutting tools, abrasion resistant tools, surface acoustic wave elements, semiconductor elements, large area heat sink lenses, etc. The present invention relates to a polishing or flattening method for diamond capable of providing a diamond substrate surface.

[0002]

2. Description of the Related Art Diamond is not only excellent in light transmittance over a wide wavelength range from infrared to ultraviolet except a part of infrared region, but also has excellent pressure resistance and is the most It has the excellent property of being hard. Therefore,
Diamond is the material of choice for scratch-free optics.

Further, diamond has the highest Young's modulus of any substance, and has the property of propagating at an extremely high speed when surface acoustic waves are excited. Therefore, diamond is attracting attention as a material for high-frequency bandpass filters used for mobile communication and the like, and research is progressing.

Further, since diamond has the highest thermal conductivity among substances, its use as a heat sink for devices such as semiconductor lasers and ICs has also been studied.

Further, diamond is attracting attention for its application as a material for a device that operates stably even under a severe environment such as high temperature and radiation, and as a material for a device that can withstand a high output operation. ing.

The reason why diamond can operate even at high temperature is that the band gap is as large as 5.5 eV. This indicates that the temperature range (intrinsic region) where the semiconductor carriers are not controlled does not exist below 1400 ° C.

As a method for artificially synthesizing diamond, an ultrahigh pressure synthesis method has been used conventionally, but recently, a diamond crystal has been synthesized even by using a vapor phase synthesis method. I came. As a result, application of diamond to optical materials, semiconductor materials and the like is further expected.

In recent years, when diamond is used for a surface acoustic wave device, a semiconductor device, a heat sink for various devices, etc., the mirror surface and flatness of the surface which is much larger than the conventional one and which can be microfabricated are provided. There is a growing demand for diamonds to have.

However, since the surface of the artificial diamond obtained by the ultra-high pressure synthesis method or the vapor phase synthesis method usually has considerably large irregularities of about 1000 μm, in such a case the artificial diamond It is necessary to polish the surface to flatten it.

However, as described above, since diamond is the hardest material in the substance, it is not always easy to polish and flatten it.

Conventionally, for polishing the diamond surface,
The method mainly by machining was used.

As a method by such mechanical processing, for example, the surface of a diamond having irregularities is roughly cut by a physical means such as a grinder, and then polished with diamond abrasive grains, and further, high-speed friction is performed at a high temperature. In this case, there is a skiff polishing which flattens the diamond surface by dissolving the diamond component in the uneven portion.

However, in the conventional polishing method, although a relatively good mirror surface can be obtained, since the polishing is based on direct contact, the polishing ability depends on the material of the substrate, the amount of warpage, the area, the thickness, etc. It has a drawback that it is greatly affected by the condition of the substrate.

Further, in order to obtain a desired smoothness in such mechanical polishing, it was necessary to control the grain size of the abrasive grains of the polishing plate, but since the grains themselves are diamond, It was difficult to control the particle size.

For example, in the case of a diamond film formed on a thin film silicon substrate, the larger the area, the more "warpage" occurs, and the amount of warpage may reach several tens of μm. In this case, when mechanical pressure is applied to the substrate by contact polishing,
The substrate may be cracked. As described above, in mechanical polishing, the size of the polishing apparatus and the polishing plate, the thickness of the diamond substrate that can be polished, etc. are limited, so the diamond film that can be mechanically polished is limited to that formed on a small-sized substrate. Therefore, mechanical polishing of a diamond film formed on a large area substrate has been extremely difficult.

On the other hand, as disclosed in Japanese Patent Laid-Open No. 26900/1990, there is a method of using a metal such as iron as an abrasive and removing a layer that has reacted with diamond, but using a contact polishing apparatus. Since it remains the same, the problems in contact polishing as described above are still unsolved.

On the other hand, as disclosed in Japanese Patent Laid-Open No. 64-68484, there is a method of irradiating an ion beam or the like without contact to smooth diamond.

However, although this method improves the mirror surface property, its smoothness is remarkably inferior to that of the above-mentioned contact polishing, and it is not possible to apply the diamond film smoothed by this method to fine processing or the like. It was possible.

Further, in Japanese Patent Application Laid-Open No. 64-62484, as an extension of the above method, a CV film is formed on a diamond film.
A method is proposed in which an amorphous carbon film, which is a substance similar to diamond, is formed by the D (chemical vapor deposition) method and then etched back (the diamond is etched from the side of the flat amorphous carbon film that has been formed once). However, it is extremely difficult to apply the diamond film obtained by this method to fine processing, because the diamond surface obtained by this method has large irregularities and it is difficult to achieve sufficient flattening. Furthermore, this method requires a long time to form an amorphous carbon film (relatively thick), and this method is not preferable from the viewpoint of manufacturing cost.

As described above, in the prior art,
A method of flattening diamond by using a diamond grindstone or diamond abrasive grains has been mainly used. Also, Ap
pl.Phys. Lett., 63 (1993), 622,
Diffusional transition of carbon atoms from diamond to these metals using metals such as cerium and lanthanum.
transfer) is used to flatten the surface of the diamond film. However, the planarization by these methods requires a long treatment time, or it is difficult to smooth the surface so that the surface irregularities are not more than submicron.

[0021]

When a single crystal diamond or a polycrystalline diamond is applied to a constituent material of an electronic device, the flatness of the diamond surface is usually from the viewpoint of forming fine wiring or the like on the diamond. Is preferably about 1/10 of the wiring length or less. According to the study by the present inventor,
When the method of Appl. Phys. Lett., 63 (1993), 622 is used, only flatness of several tens of μm can be obtained. Also, LS
I Design and Manufacturing Technology (written by Michitada Morisue, published by Denki Shoin, 198
7 years) p370 contains PSG (phospho-silicate glass)
s) When etching the resist layer formed above,
Using the fact that when O ₂ is added to CF ₄ which is an etching gas, the etching rate of the resist is increased, and when H ₂ is added, the etching rate of the resist is decreased, the etching rate of the resist and PSG are set to be the same. Discloses a method of simultaneously etching these to leave a flat PSG film. In such a planarization process by the etching method in the semiconductor process, the dry etching rate of the sacrificial layer (PSG in this case) and the film to be planarized can be easily made the same by changing the gas composition. Met.

However, when this method is applied to the flattening of the diamond film, it is difficult to make the dry etching rate of the diamond and the sacrificial layer the same, and even if the same rate is obtained, The etching rate must be extremely slow. Therefore, the flattening of the diamond film has a drawback that a considerably long processing time is required.

In general, it is preferable that the surface roughness of diamond is as small as possible in order to stably form a fine wiring pattern or the like on the surface.

Accordingly, it is an object of the present invention to provide a diamond flattening or polishing method which solves the above-mentioned conventional problems.

Another object of the present invention is to provide a method of flattening or polishing a diamond, in which a diamond surface on which fine wiring and the like can be stably formed is provided in a short time.

Still another object of the present invention is a diamond capable of non-contact mirror finish polishing without being substantially affected by the substrate material such as substrate material, warp amount, area and thickness. To provide a flattening or polishing method.

Still another object of the present invention is to provide a method of flattening or polishing diamond, which allows a diamond film on which fine processing can be performed to be obtained at low cost.

[0028]

According to the present invention, when flattening a diamond surface by a dry method, the reduction rate of the convex portion of the diamond surface is set relatively to the reduction rate of the concave portion of the diamond surface. A method of planarizing diamond is provided which is characterized by increasing the size.

According to the present invention, further, after forming a flat film made of a material different from the diamond on the surface of the diamond; under the condition that both the diamond and the film can be etched by dry etching, There is provided a method for flattening a diamond, which comprises removing the irregularities on the coating and the diamond surface to smooth the surface of the diamond.

According to the present invention, further, a liquid coating agent containing a material different from the diamond is dropped on the surface of the diamond to be hardened to form a coating film having a spherical surface on the diamond; dry etching. According to the conditions that can etch both the coating and diamond,
There is provided a diamond polishing method, characterized in that a spherical diamond surface is obtained by removing the irregularities on the coating film and the diamond surface.

According to the present invention, further, the first step of forming a flat film made of a material different from that of the diamond on the surface of the diamond and the second step of performing ion implantation into the diamond through the film. A method for flattening a diamond is provided, which comprises a step and a third step of removing the coating film and removing the diamond portion that has been altered by the ion implantation from the diamond.

In such a diamond flattening method, the above-mentioned first to third steps may be repeated if necessary in order to enhance the smoothness of the diamond surface.

Hereinafter, the present invention will be described in detail with reference to the drawings as necessary.

(Diamond) The type of diamond that can be used in the present invention is not particularly limited. More specifically, for example, the planarization method or polishing method of the present invention includes natural diamond, diamond consisting of a bulk single crystal artificially produced by a high pressure synthesis method, or a substrate artificially produced by a vapor phase synthesis method. The present invention can be applied to flatten or polish the surface of various diamonds such as diamond composed of thin film polycrystal or thin film single crystal formed on.

(Coating) The coating (or sacrificial layer) to be formed on the diamond surface in order to flatten the surface of the diamond can be formed by using various materials different from diamond. Such a coating can be formed by various methods. More specifically, for example, a method of applying a liquid coating agent containing a material different from diamond so as to fill the irregularities on the diamond surface and solidifying (by solvent evaporation etc.); or a sol-state coating on the diamond surface according to the sol-gel method. After the material is applied, it is converted into a gel state and solidified to form a flat surface; and the like, a coating can be relatively easily formed and flattened (a flat coating is formed).

When the coating film is formed using a liquid material, an appropriate amount of the liquid material is dropped on the surface of the diamond to be flattened and spin coated (spin coating) using a spinner or the like.
It is preferable to carry out.

As the material (material different from diamond) to be used for forming the film, a material which can form a relatively stable and uneven surface on the diamond surface by coating on the diamond surface is preferably used. More specifically, for example, as such a material,
Examples thereof include those containing an organic material containing silicon (Si), boron (B) or the like as a main component, or those containing an inorganic material containing silicon (Si), boron (B) or the like as a main component.

Examples of the film forming material containing an inorganic material containing Si, B or the like as a main component include an inorganic silicon compound and an inorganic boron compound. For example, when a coating film made of an inorganic silicon compound or an inorganic boron compound is formed according to the sol-gel method, Si is formed on the surface of diamond.
A gel layer can be formed by spin-coating (rotating coating) an O ₂ -based or B ₂ O ₃ -based sol using a spinner or the like and then converting the sol by heating or the like. For example, a SiO ₂ based coating solution used in a semiconductor process can be easily used.

As the film-forming material containing an organic material as a main component, a relatively inexpensive polyimide material used in a semiconductor device manufacturing process or the like can be simply used.
The present invention is not limited to this, and other organic polymers and the like can be used.

As a material containing an organic material containing Si, B or the like as a main component, a water-soluble colloidal, polycinnamic acid-based, cyclized rubber-based, quinone diazide-based liquid photoresist or the like can be preferably used. .

(Dry etching) In the present invention,
Reactive ion etching (RIE) is most preferably used as the dry etching method, but plasma etching, ion beam etching, or the like can also be used. Whichever etching is used,
It is possible to obtain almost the same smoothing effect.

The gas used for dry etching is
Ar, He, CF ₄ , CHF ₃ , SF ₆ , BCl ₃ , C
It is possible to use ordinary etching gases such as HCl ₃ alone or in combination. A gas system in which a small amount of O ₂ , N ₂ O, N ₂ or the like is mixed with these gases may be used if necessary.

In the present invention, the condition under which both the coating film and diamond can be etched by dry etching is basically realized by suppressing the etching selection ratio between the coating film and diamond during dry etching to be smaller. . In the present invention, it is preferable that the etching selectivity between the coating and the diamond is in the range of 1: 2 to 2: 1. Further, the etching selectivity between the coating and the diamond is approximately 1: 1 (that is, ,
Most preferred is an etching selectivity ratio in the range 0.8: 1 to 1: 0.8, even 0.9: 1 to 1: 0.9.

For example, when dry etching is performed in a gas system in which O ₂ is mixed with Ar, the etching selection ratio between the coating film and diamond is set by setting the ratio of the addition amount of O _{2 to} Ar to be 0 to 10%. It can be adjusted to approximately 1: 1.

(Ion Implantation) Ion implantation in the present invention can be carried out according to a usual ion implantation technique.

The elements used for ion implantation are not limited,
Any element can be appropriately selected and used. The ions used at this time are preferably elements having a mass sufficient to destroy and change the crystalline state of diamond and have a size large enough to be deeply introduced into diamond. More specifically, for example, Ar, Ne, H
e, Al, Xe, Cu and the like can be preferably used.

In the present invention, the diamond blocking cross section (E) against the implanted ions and the coating blocking cross section (F) against the implanted ions are optionally applied during the ion implantation.
Are almost equal to each other (preferably, the ratio (F / E) of blocking cross sections
May be 0.1 to 10, more preferably 0.9 to 1.1). More specifically, the above is preferable.

Here, the "blocking cross section" is the quotient of the loss energy lost by the interaction of the implanted ions with the substance when passing through the film and the diamond, divided by the number of atoms or molecules per unit volume. Stipulated. In this way, when the blocking cross-sections of diamond for implanted ions and the blocking cross-section of the coating for implanted ions are made to substantially match, the range of implanted ions introduced into the diamond and the coating can be made equal with good reproducibility. It will be possible.

The blocking cross section of the coating film against the implanted ions can be adjusted relatively easily, for example, by adding an appropriate amount of a metal element to the material used for forming the coating film and mixing them uniformly.

Examples of the metal element added for such a purpose include Mg, Al, Ti, W, Mo, Au and Pt.
Etc. can be used suitably. Further, the addition amount of the metal element can be obtained by computer simulation based on the material forming the film, the type of implanted ions, and the type of the metal element to be added.

(Removal of coating film) Upon removal of the coating film, chemical or physical etching depending on the material forming the coating film, or chemical treatment with a release agent, HF (hydrofluoric acid) or the like is appropriately selected and used. You can

(Removal of Diamond Deteriorated Portion) In order to remove a portion in which the diamond is altered, either dry etching or chemical wet etching can be used. Whichever etching is used, almost the same effect can be obtained.

For dry etching, hydrogen, oxygen,
Alternatively, plasma etching utilizing gas discharge of halogen gas or the like can be preferably used. As the wet etching, etching using chromic acid treatment or the like can be preferably used.

(Level of Flattening or Polishing) In the flattening or polishing method of the present invention, the smoothness of the diamond surface obtained is, for example, R _Max or R _a (JIS B 06.
(Based on 01)).
More specifically, for example, when R _Max of the diamond surface before flattening or polishing is A (μm) and R _Max of the diamond surface after flattening or polishing is B (μm), in the present invention, , B / A is usually preferably 1/3 or less, more preferably 1/5 or less (particularly 1/10 or less).

(Diamond Polishing Method) The operation mechanism of one embodiment of the diamond polishing method of the present invention will be described with reference to FIG.

In this diamond polishing method, first, as shown in FIG. 1A, a diamond film 2 synthesized on a predetermined substrate 1 (for example, a silicon substrate) is prepared.
Usually, unevenness exists on the entire surface of the diamond 2. On the surface of such a diamond 2, a flat film made of a material different from that of the diamond is formed.

As a result, as shown in FIG. 1B, the unevenness existing on the entire surface of the diamond 2 on the substrate 1 is buried by the coating film 3 and the unevenness of the surface of the diamond 2 is substantially affected. The coating 3 having a flat surface is formed without being subjected to the stress.

Then, the film 3 is formed in a predetermined gas atmosphere.
Has a substantially flat surface by dry etching under a condition capable of etching both the diamond and the diamond 2 (for example, the etching selectivity between the coating film and the diamond is approximately 1: 1 as described above). Etching is performed from the surface of the film 3.

As a result, while maintaining high flatness,
First, the coating 3 and the irregularities on the surface of the coating 3 and the diamond 2 are removed (for example, simultaneously) from the substrate 1, and the surface of the diamond 2 is smoothed.

As a result, as shown in FIG. 1 (c), most of the irregularities present on the entire surface of the coating 3 and the diamond 2 are finally removed, and a flat and mirror-finished diamond surface 4 is obtained. You can

Another aspect of the diamond polishing method of the present invention will be described with reference to FIG.

First, as shown in FIG. 2A, a substrate made of diamond 10 is prepared. Irregularities are usually present on the surface of the substrate made of diamond 10. A liquid coating material made of a material different from diamond is dropped and cured on the entire surface of the substrate made of such diamond 10 to form a coating film 11 having a spherical surface.

As a result, the unevenness existing on the surface of the substrate made of diamond 10 is buried by the coating film 11 and a smooth surface is formed without being substantially affected by the degree of unevenness on the surface of the substrate made of diamond 10. The coating 11 having is formed.

Next, the film 1 is formed in a predetermined gas atmosphere.
1 and the diamond 10 can be etched (for example, under the condition that the etching selectivity between the coating 11 and the diamond 10 is about 1: 1), by dry etching, from the side of the spherical surface of the coating 11. Etch.

As a result, first, the coating 11 is further removed from the substrate made of the diamond 10 (at the same time) asperities on the surface of the substrate made of the coating 11 and the diamond 10 to obtain a spherically polished diamond surface. be able to.

As a result, as shown in FIG. 2B, the diamond lens 12 whose surface is finally polished into a spherical shape.
Can be obtained.

Similar to the above method, FIG.
By polishing the back surface of the substrate made of diamond 10 as shown in FIG. 4, it is also possible to obtain a diamond lens 14 whose both surfaces are spherically polished, as shown in FIG.

One mode of the method for flattening diamond according to the present invention will be described with reference to FIG.

In such an embodiment of the flattening method, as shown in FIG.
Then, a coating 30 having a flat surface and made of a material different from diamond is formed.

As a result, as shown in FIG. 5B, the unevenness present on the surface 25 of the diamond 20 is buried by the coating film 30, and a flat coating film surface 35 is obtained. Here, since the coating film 30 can be formed flat regardless of the unevenness remaining on the surface 25 of the diamond 20,
The film thickness of the coating 30 is different for each region of the diamond 20.

Next, as shown in FIG. 5C, the diamond 20 is ion-implanted (from the side of the coating film 30) through the coating film 30 having the flat surface 35. As a result, the implanted ions 40 are introduced substantially uniformly over the entire surface of the diamond 20 after passing through the coating film 30.

At this time, as shown in FIG. 6D, in the region 100 where the film thickness of the film 30 is large, the implanted ions 40 are shallowly introduced into the diamond 20, while the film 30 is formed on the other hand.
In the region 105 where the film thickness is small, the implanted ions 40 are deeply introduced into the diamond 20.

As shown in FIG. 6E, the implanted ions 40
The crystal structure of the diamond in which is introduced is destroyed by ion bombardment to be modified or altered, and becomes, for example, amorphized or graphitized.

Next, the coating film 30 is completely removed from the surface 25 of the diamond 20, and the portion 45 where the diamond is altered by ion implantation is removed. As a result, as shown in FIG. 6 (f), most of the relatively large irregularities present on the surface 25 of the diamond 20 are removed as the altered portion 45 of the diamond, and the smooth surface 2
6 is exposed.

In such a flattening mode, if the desired flatness cannot be obtained on the surface 26 of the diamond 20 by one flattening treatment, the above-mentioned flattening treatment is repeated one or more times. By doing so, it is possible to further flatten the remaining small unevenness and obtain a diamond having a smoother surface.

Further, according to such a flattening mode of the diamond, as shown in FIG. 7A, by adding a trace amount of a metal element to the surface 25 of the diamond 20, the inhibition cross-section area of the diamond against the implantation ion and the implantation are introduced. The coating 31 may be formed to obtain a coating 31 having a flat surface so that the blocking cross-section of the coating against ions is substantially the same.

As a result, as shown in FIG. 7B, the irregularities present on the surface 25 of the diamond 20 are buried by the coating film 31, and a flat coating film surface 36 is obtained.

Next, as shown in FIG. 7C, the diamond 20 is ion-implanted through the coating 31 having the flattened surface 36. As a result, the implanted ions 4
After 0 passes through the coating 31, it is introduced substantially uniformly over the entire surface of the diamond 20.

At this time, as shown in FIG. 8D, since the blocking cross section of diamond against the implanted ions and the blocking cross section of the coating against the implanted ions are substantially the same, the implanted ions 40 are the same from the coating surface 36. Efficiently introduced into all areas of the diamond at depth.

As a result, as shown in FIG. 8E, the crystal structure of the diamond in the portion where the implanted ions are introduced from the coating surface 36 at the same depth is destroyed by the ion bombardment to be altered, for example, amorphous. Qualitify or graphitize.

Next, the coating 31 is completely removed from the surface of the diamond 20, and the portion 45 where the diamond is altered by ion implantation is removed.

As a result, as shown in FIG. 8F, most of the relatively large irregularities present on the surface 25 of the diamond 20 are removed as the altered portion 45 of the diamond, so that the flattening is performed once. The treatment makes it possible to obtain diamonds with a very flat surface 27.

Another aspect of the flattening method of the present invention will be described with reference to FIG. 9 (numerical values in FIG. 9 indicate an example of the depth of the diamond surface recess). In this aspect, when the diamond surface is flattened by the dry method, the reduction rate of the convex portion of the diamond surface is made relatively higher than the reduction rate of the concave portion of the diamond surface, so that the diamond surface is flattened. The diamond surface can be obtained in a short time.
In other words, in this embodiment, rather than making the etching rates of different materials the same, rather, by positively differentiating the reduction rates for the convex and concave portions of the diamond surface, a relatively short It is possible to obtain a smooth diamond surface in time.

That is, in this embodiment, the convex portion of the diamond surface is shaved relatively quickly, and the concave portion of the surface is shaved relatively slowly. (In other words, the portion to be shaved is preferentially reduced. Therefore, even an extremely flat surface (for example, the surface R _max is about 0.5 μm or less) can be obtained in a relatively short time. More specifically, for example,
By making a relative difference in polishing speed or dry etching speed in the sub-μm unit between the convex portion and the concave portion on the diamond surface, the size (R _max ) of the concave and convex can be set to, for example, about 0.5 μm or less.

In the present embodiment, the reduction rate (etching rate or polishing rate) of the convex portion of the diamond surface and the reduction rate of the concave portion of the diamond surface are determined by, for example, the method of Chen et al. (Appl. Phys. Lett., 63 ( 5) , 622 (199
It can be measured by 3)). When the reduction rate of the convex portion of the diamond surface is C (Å / min) and the reduction rate of the concave portion of the diamond surface is D (Å / min), the C / D ratio is usually in the present embodiment. 1.5 or more, further 3.0
The above is preferable.

Diamond is Appl. Phys. Lett., 63
(5) , 622 (1993), it becomes brittle when it reacts with a metal to form a carbide layer. On the other hand, it is known that when a substance having a property of applying compressive strain to diamond, such as boron, is added to diamond, it becomes hard. In this embodiment, one or more of these properties of diamond are utilized to planarize the diamond surface.

In the present embodiment, as the dry method, either a contact (or mechanical) polishing method and / or a dry etching method can be used, but it is affected by "warpage" of the substrate surface to be flattened. From the viewpoint of difficulty, it is preferable to use the dry etching method.

As the sacrificial layer, spin-on-glass (SO
It is preferred to use membranes based on G) or tetraethoxysilane (TEOS). Here, SOG refers to liquid glass in which silicon glass is dissolved or dispersed in a solvent. Generally, SOG can be solidified by a heat treatment at about 200 to 350 ° C. The thickness of the sacrificial layer is 0.
It is preferably about 1 to 10.0 μm.

In the present embodiment, it is preferable that the sacrifice layer is uniformly etched to expose the protrusions on the diamond surface, impurities are attached to the exposed protrusions, and annealing is performed if necessary. This allows the impurities to react with the protrusions to form a reaction layer having a predetermined thickness on the diamond surface to be smoothed.

Since such a reaction layer (convex portion) is composed of altered or modified diamond, the convex portion can be easily removed by etching or contact polishing.

As the impurities, for example, a metal selected from iron, nickel, manganese, cerium, or lanthanum is preferably used. When introducing the impurities, a dry process such as ion implantation or vapor deposition may be used, or a wet process may be used.

The above-mentioned annealing is preferably carried out, for example, in vacuum at a temperature of 500 to 2000 ° C. for 1 to 30 minutes. A reaction layer having a thickness of about 0.1 to 1 μm can be formed on the diamond surface by reacting the diamond surface protrusions with impurities based on such annealing.

In this embodiment, if necessary, a compressive strain may be applied to the concave portion of the diamond surface to reduce the reduction rate of the concave portion. In this case, for example, using a sacrificial layer containing a predetermined amount of impurities as the sacrificial layer,
After exposing the convex parts of the diamond surface and annealing,
It is preferable to mix the impurities into the recesses on the diamond surface. As such an impurity, for example, boron is preferably used.

Hereinafter, this aspect will be specifically described with reference to FIG.

As shown in FIG. 9A, a sacrificial layer 52 is formed on the surface of the diamond 51 by using organic SiO ₂ such as spin-on glass as a sacrificial layer forming material, and the diamond surface is once flattened. At this time, when boron is mixed in the concave portion of the diamond surface, a film containing a large amount of boron (sacrificial layer) may be formed.

Next, as shown in FIG. 9B, the spin-on glass 52 is etched back (reduced by etching) using a plasma etching device or the like to expose the diamond protrusions on the surface of the diamond 51. This allows
It is possible to react desired impurities only on the convex portions on the surface of the diamond 51.

Next, as shown in FIG. 9C, the entire surface of the exposed convex portion is made of a transition metal or the like.
Impurities 53 that react with diamond are applied by, for example, vapor deposition. As the transition metal used at this time, iron (Fe) is preferably used, but in addition, Ti,
Transition metals such as Ni, Mo and Ce can be used.

Next, as shown in FIG. 9D, if necessary, in order to promote the reaction between the diamond and the impurities,
Annealing is performed in a vacuum or an inert gas atmosphere. Since the reaction temperature of the annealing temperature changes depending on impurities,
The optimum temperature is determined by the type of impurities. As a result, the diamond reacts with the impurities in the convex portion,
The spin-on-glass part becomes unreacted.

When a lamp annealing furnace is used during this annealing, the size of the reaction portion in the depth direction can be controlled (for example, between about 0.1 μm and about 1 μm). Becomes As a result, it becomes possible to form the reaction portion only on the very surface portion of the diamond 51.

By performing dry etching or contact polishing on the surface of the diamond 51 which has reacted with the impurities 53 as described above, the convex portions that have reacted with the impurities 53 are reduced (at a reduction rate higher than that of the concave B) by a reduced rate. Then, as shown in FIG. 9 (e), single crystal or polycrystalline diamond having a flat surface is obtained.

It is also possible to introduce the above impurities by using an ion implanter. In this case, since the portion of the SiO ₂ film functions as a mask, the impurity is not implanted into the surface recess of the diamond 51. Even when ion implantation is used as described above, annealing may be performed as necessary in order to further react impurities with diamond.

When boron is introduced into the concave portion of the diamond surface, boron can be easily mixed as an impurity to the order of%. Moreover, the fracture of diamond becomes brittle fracture. According to the knowledge of the present inventor, in this case, it is considered that dislocation does not proceed in a state where a large amount of impurities are mixed. Therefore, by including a large amount of boron in the sacrificial layer for planarization described above, and annealing after planarizing, it becomes possible to selectively mix boron into the recess. This allows
It becomes possible to control the rate of reduction of the projections and recesses, and it is possible to obtain a flat surface by etching or polishing in a short time.

Hereinafter, examples will be described more specifically based on the present invention.

[0104]

Example 1 A 10 μm thick polycrystalline diamond film formed on a 3-inch square silicon substrate was used as the substrate. When the surface roughness was examined, the average surface roughness _Ra was 2000 Å (200
nm).

A coating agent (X-Si- (OH) _n ) (OCD manufactured by Tokyo Ohka Co., Ltd.) containing an inorganic silicon compound as a main component was spin-coated on this substrate at 2000 rpm, and then baked at 400 ° C for 30 minutes. Then, a coating layer was formed. The thickness of the obtained coating layer is 6000.
It was Å.

This substrate was placed in a dry etching apparatus and etched using Ar gas (100%). The etching rate was 250 Å / min, and the etching selectivity between the coating layer and diamond was 1: 1. By etching for 40 minutes, the irregularities on the coating layer and the diamond surface were etched to obtain mirror-finished diamond having an average surface roughness Ra of 100Å.

Using the diamond substrate thus obtained, a fine pattern of resist was formed on the substrate using an ultraviolet reduction projection exposure machine, and a patterning of 0.5 μm was obtained.

Example 2 Polycrystalline diamond having a thickness of 10 μm formed on a 3-inch square silicon substrate was used as a substrate. When the surface roughness was examined, the average surface roughness _Ra was 2000 Å.

On this substrate, a coating agent (X-Si (OH) n) (OCD manufactured by Tokyo Ohka Kogyo Co., Ltd.) containing an inorganic silicon compound as a main component was spin-coated at 2000 rpm, and then baked at 400 ° C. for 30 minutes. To form a coating layer. The thickness of the obtained coating layer is 6000Å
Met.

This substrate was placed in a dry etching apparatus and dry-etched using Ar (95%) + O ₂ (5%) gas system. Diamond has an etching rate of 2
80 Å / min, coating layer is 250 Å / min,
The etching selection ratio between the coating layer and diamond was 1: 0.9. By etching the irregularities of the coating layer and the diamond layer by etching for 40 minutes, specular diamond having an average surface roughness _Ra of 120Å was obtained.

Using the diamond substrate thus obtained, a fine pattern of resist was formed on the substrate using an ultraviolet reduction projection exposure machine, and a patterning of 0.5 μm was obtained.

Example 3 Polycrystalline diamond having a thickness of 10 μm formed on a 3-inch square silicon substrate was used as a substrate. When the surface roughness was examined, the average surface roughness _Ra was 2000 Å.

On this substrate, a polyimide containing an organic silicon compound as a main component was spin-coated at 5000 rpm and then baked at 400 ° C. for 30 minutes to form a coating layer. The thickness of the obtained coating layer is 6000.
It was Å.

This substrate was placed in a dry etching apparatus and subjected to dry etching using CF ₄ gas. The etching rate is 200 Å / min for diamond and 250 Å / min for a polyimide coating layer, and the etching selectivity between the coating layer and diamond is 1: 1.2.
It was 5. The irregularities of the coating layer and the diamond layer were etched by 50 minutes of etching to obtain a specular diamond having an average surface roughness _Ra of 120Å.

Using the diamond substrate thus obtained, a fine pattern of resist was formed on the substrate using an ultraviolet reduction projection exposure machine, and a patterning of 0.5 μm was obtained.

Example 4 As shown in FIG. 2A, a 5 mm square diamond 10 was used.
A coating agent (X-Si- (OH)) containing an inorganic silicon compound as a main component is formed on (average surface roughness _Ra = 2000Å).
_n ) (manufactured by Tokyo Ohka Co., Ltd.) was added dropwise, and then at 400 ° C for 3
After baking for 0 minutes, a dome-shaped coating layer 11 was formed. The maximum thickness of the obtained coating layer 11 is 60.
It was 00Å.

The diamond 10 was placed in an etching apparatus, and dry etching was performed using a mixed gas of Ar (95%) + O 2 (5%). The etching rate was 250 Å / min, and the etching selectivity between the coating layer and diamond was 1: 1. By etching a part of the surfaces of the coating layer 11 and the diamond 10 by etching for 40 minutes, as shown in FIG.
As shown in (b), a single-sided spherical diamond lens 12 having an average surface roughness _Ra of 100Å was obtained.

Example 5 As shown in FIG. 3A, a 5 mm square diamond 10 was used.
A coating agent (X-Si- (OH)) containing an inorganic silicon compound as a main component is formed on (average surface roughness _Ra = 2000Å).
_n ) were arranged side by side and dropped, and then baked at 400 ° C. for 30 minutes to form a plurality of dome-shaped coating layers 11. The maximum thickness of the obtained coating layer 11 is 15
It was 00Å.

This diamond 10 was placed in an etching apparatus, and dry etching was performed using a mixed gas of Ar (95%) + O 2 (5%). The etching rate was 250 Å / min, and the etching selectivity between the coating layer and diamond was 1: 1. The etching for 10 minutes, a portion of the surface of the coating layer 11 and the diamond lens 10 by etching, as shown in FIG. 3 (b), the average surface roughness R _a is 100Å
A single-sided spherical diamond lens 13 was obtained.

Example 6 Single-sided spherical diamond lens 12 obtained in Example 4
A coating agent (X-Si- (OH) _n ) containing an inorganic silicon compound as a main component is dripped on the back surface of the
Bake at C for 30 minutes to form dome-shaped coating layer 1
1 was formed. The maximum thickness of the obtained coating layer 11 was 6000Å.

This substrate is placed in an etching apparatus, and A
Dry etching was performed using a mixed gas of r (95%) + O ₂ (5%). The etching rate is 25
At 0Å / min, the etching selectivity between the coating layer and diamond was 1: 1. By coating for 40 minutes, the coating layer 11 and the diamond lens 1
Part of the back surface of No. 2 was etched to obtain a double-sided spherical diamond lens 14 having an average surface roughness _Ra of 100Å as shown in FIG. 4 (b).

Example 7 First, the following three types of substrates made of diamond were prepared (STEP 1).

(1) A single crystal diamond synthesized by the ultra-high pressure synthesis method is polished with a diamond powder of # 200 (abrasive grains of 80 to 100 μm) (2) A single crystal diamond synthesized by the ultra-high pressure synthesis method (3) Polycrystalline diamond formed on Si substrate by vapor phase synthesis method First, the surface roughness of each substrate of (1) to (3) above is measured by a surface roughness meter (for example, DEKTAK). Was measured and the results are shown in Table 1 (STEP 1) below.

Next, an appropriate amount of a cyclized rubber photoresist agent (trade name: OMR, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was dropped on the surface of each substrate, and spin coating was performed with a spinner. The photoresist agent was dried by heating at a temperature of 110 ° C. for 30 minutes in the air to form a resist film having a film thickness of about 1 μm (S
TEP2). The surface roughness of each resist film thus obtained was measured using a surface roughness meter, and the results are shown in Table 1 (STEP 2).

Next, using an ion implanter, Ar ions are accelerated from the resist film surface formed on each of the substrates (1) to (3) above with acceleration voltages of 50 keV and 500 ke.
V, 1 MeV, 2 MeV in dose amount 10 ¹⁵ cm ^-2
Ion implantation was done. As a result, Ar ions were implanted into the irregularities remaining on the surface of each substrate, and the portions were made amorphous or graphitized. After the ion implantation, the resist film was completely removed from each substrate with a release agent.

Next, the substrate temperature is set to 800 ° C., and the amorphized or graphitized portion is exposed to the plasma of a gas containing hydrogen so that the amorphized or graphitized portion is removed from each substrate surface. It was removed and the diamond surface was flattened (STEP 3). The surface roughness of each of the obtained substrates was measured using a surface roughness meter. The measurement results are also shown in Table 1 (STEP 3) below.

[0127]

[Table 1]

As shown in Table 1, by performing the above-mentioned flattening treatment, the surface roughness of all the diamond substrates (1) to (3) can be made extremely small. . That is, it was confirmed that the flattening effect of the present invention has a large flattening effect.

Example 8 In Example 7, the flattening treatment was performed once (1) to
Each substrate of (3) was prepared (STEP 4). Therefore, the following treatment was performed on the assumption that the surface roughness of each substrate shown in Table 2 (STEP 4) below is equal to the surface roughness of each substrate shown in Table 1 (STEP 3).

Next, as in Example 7, a resist film was formed on each substrate (STEP 5). The surface roughness of each obtained resist film was measured. The obtained results are shown in Table 2 (STEP 5) below.

Next, using an ion implanter, Ar ions are accelerated from the resist film surface formed on each of the substrates (1) to (3) above with acceleration voltages of 50 keV and 500 ke.
V, 1 MeV, 2 MeV in dose amount 10 ¹⁵ cm ^-2
Ion implantation was done.

After the ion implantation, the resist film was completely removed from each substrate in the same manner as in Example 7, and the portion amorphized or graphitized by the ion implantation was exposed to the plasma of a gas containing hydrogen, The diamond surface was removed from each substrate surface to flatten the diamond surface (STEP 6). The surface roughness of each obtained substrate was measured. The obtained results are also shown in Table 2 (STEP 6) below.

[0133]

[Table 2]

As shown in Table 2 above, by repeating the above-described flattening process twice, the surface roughness of each substrate is further increased as compared with the case where one flattening process is performed. It turned out that it can be made smaller.

Particularly, in this embodiment, 2 is formed on the substrate surface.
By subjecting the substrate made of polycrystalline diamond, which had a surface roughness of 000Å, to two planarization treatments,
It was shown that the surface roughness can be flattened to about 1/10. That is, it was confirmed that the flattening effect was very large.

Example 9 Similar to Example 7, each of the substrates (1) to (3) was prepared (STEP 1), and then a resist film was formed on each substrate (STEP 2). Therefore, Table 3 (STEP1)
The surface roughness of each substrate shown in Table 1 is the same as the surface roughness of each substrate shown in Table 1 (STEP1).
The surface roughness of the resist film of each substrate shown in 2) is
The following treatment was performed assuming that the surface roughness of the resist film of each substrate shown in Table 1 (STEP 2) was the same.

Next, using an ion implantation apparatus, (1)-
From the resist film surface formed on each substrate of (3), A
Accelerating voltage of r ion is 50 keV, 500 keV, 1 Me
Ion implantation was performed at 10 ¹⁵ cm ^-2 with a dose amount of V and 2 MeV. After the ion implantation, the resist film was completely removed from each substrate to expose the surface of each substrate.

In this example, when removing the amorphous or graphitized portion of diamond from the surface of each substrate by ion implantation, wet etching with chromic acid was performed without using plasma etching.

By the above wet etching, the amorphized or graphitized portion is removed from the substrate surface,
The diamond surface was flattened (STEP 3).
The surface roughness of each obtained substrate was measured. The obtained results are also shown in Table 3 (STEP 3) below.

[0140]

[Table 3]

As shown in Table 3, even when the flattening treatment is performed by wet etching with chromic acid, the portion where diamond is amorphized or graphitized by ion implantation is efficiently removed from the substrate surface. It was confirmed that the surface roughness of each substrate can be made extremely small.

Example 10 The same planarization treatment as in Example 7 was performed using only the substrate made of polycrystalline diamond formed on the Si substrate by the vapor phase synthesis method. In this example, in order to investigate the effect of the planarization treatment by the addition of the metal element on the implanted ions, A
1, W, Mo, Fe, and Au were respectively added at 10 ²⁰ cm ^-3 and mixed uniformly, and a photoresist agent (trade name: O
MR, manufactured by Tokyo Ohka Co., Ltd.) was used.

In the same manner as in Example 7, a resist agent added with each metal element or a resist agent without addition was added on each substrate.
Each was spin-coated with a spinner to form a resist film (S
TEP2). In this way, the surface roughness on the surface of the obtained resist film was measured, and all were set to 100 Å or less.

Next, using an ion implanter, Ar ions are implanted from the surface of the resist film formed on each substrate at an acceleration voltage of 50 keV, 500 keV, 1 MeV, 2 MeV at a dose of 10 ¹⁵ cm ^-2. Was done. After the ion implantation, the resist film was removed from each substrate, and the amorphous or graphitized portion by the ion implantation was
The diamond surface was exposed by exposing it to the plasma of a gas containing hydrogen to flatten the diamond surface (STEP).
3). The surface roughness of each of the obtained substrates was measured, and the results are also shown in Table 4 (STEP 3) below.

[0145]

[Table 4]

As shown in Table 4 above, by using the resist agent to which the metal element is added, it is possible to further reduce the substrate surface roughness as compared with the case where the resist agent to which no metal element is added is used. confirmed. According to the knowledge of the present inventor, by uniformly adding the metal element into the resist film, the blocking cross-section of the resist film for Ar ions to be ion-implanted and the blocking cross-section of each substrate made of diamond are almost the same. It is presumed that this is because they match.

Example 11 Similar to Example 10, the same planarization treatment as in Example 7 was performed using a substrate made of polycrystalline diamond formed on a Si substrate by a vapor phase synthesis method.

However, in this embodiment, instead of forming the resist film on the substrate, Si is formed on the substrate by the sol-gel method.
An O ₂ film was formed.

Further, in this example, in order to investigate the flattening effect by the addition of the metal element, Al, W, Mo, Fe, A
Gels each containing 10 ²⁰ cm ^{-3 of} u and uniformly mixed were used.

First, on each substrate, a SiO sol containing a metal element or a SiO sol containing no metal element was spin-coated with a spinner. By heating according to the sol-gel method, the SiO-based sol on the substrate is solidified to form Si.
A gel layer made of O ₂ was formed (STEP 2). The surface roughness of the surface of the SiO ₂ layer thus obtained was measured and all were set to 100 Å or less.

Next, using an ion implantation apparatus, Ar ions are ion-exchanged from the surface of the SiO ₂ layer formed on each substrate at an acceleration voltage of 50 keV, 500 keV, 1 MeV, 2 MeV at a dose of 10 ¹⁵ cm ^-2 . Injected. After the ion implantation, the SiO ₂ layer was entirely removed from the substrate by HF treatment to expose the surface of each substrate. Then, the amorphous or graphitized portion of diamond was exposed to the plasma of a gas containing hydrogen to remove it from the surface of each substrate, and flattened (STEP 3). The surface roughness of each of the obtained substrates was measured, and the results are shown in Table 5 below (STEP
It is also shown in 3).

[0152]

[Table 5]

As shown in Table 5, it was confirmed that the surface roughness of the substrate can be made extremely small even when the SiO ₂ layer is formed on the substrate by the sol-gel method and the planarization treatment is performed. Was done. It was also confirmed that the surface roughness of the substrate can be further reduced by using the sol agent to which various metal elements are added. According to the knowledge of the present inventor, it is presumed that this is because the blocking cross-section of the SiO ₂ layer and the blocking cross-section of the substrate made of diamond are almost the same.

Based on the results obtained in Examples 10 and 11 described above, it is possible to appropriately set the species of the metal element to be added to the resist agent and the amount thereof added depending on the species of the implanted ions and the implantation conditions. It has been found that a substrate having a desired flatness can be realized by performing the flattening process only once.

Example 12 Similar to Example 10, the same planarization process as in Example 7 was performed using only the substrate made of polycrystalline diamond formed on the Si substrate by the vapor phase synthesis method.

However, in this embodiment, Ar, Ne, H
Ion implantation was performed using e, Al, Xe, and Cu ions.

In the same manner as in Example 7, a resist agent was spin-coated on each substrate by a spinner to form a resist film (STEP 2). The surface roughness on the surface of the resist film thus obtained was measured, and all were set to 100 Å or less. Next, using an ion implantation device, Ar, Ne, and H are removed from the surface of the resist film formed on each substrate.
The ions of e, Al, Xe, and Cu were ion-implanted at 10 ¹⁵ cm ^-2 with a dose amount of 50 keV, 500 keV, 1 MeV, and 2 MeV, respectively. After the ion implantation, the resist film is removed from each substrate, and the portion where the diamond is made amorphous or graphitized by the ion implantation is exposed to the plasma of a gas containing hydrogen to remove it from each substrate surface for planarization. (STEP 3).
The surface roughness of each of the obtained substrates was measured, and the results are also shown in Table 6 (STEP 3) below.

[0158]

[Table 6]

As shown in Table 6, it was confirmed that the surface roughness of the substrate could be greatly reduced by using all kinds of ions used, and the flattening effect was confirmed.

Example 13 As shown in FIG. 9A, 0.7 μm of spin-on glass 52 was coated on a (100) plane single crystal diamond substrate 51 at a speed of 4000 revolutions (rpm). Then, in order to sinter the spin-on glass 52, N
Annealed at 350 ° C. for 20 minutes in ₂ atmospheres.

Further, as shown in FIG. 9 (b), a CFC 50 (CF ₄ ) gas was used by using a reactive etching apparatus.
The spin-on-glass (SiO ₂ ) sintered as described above was etched under the conditions of sccm, RF power of 13.56 MHz and 300 W for 10 minutes. This gives 0.4μ
The m spin-on-glass was etched back to expose the protrusions on the diamond surface.

As shown in FIG. 9C, an iron beam (F) was formed on the exposed convex portion by using an electron beam evaporation apparatus.
e) was vapor-deposited by 0.2 μm.

Then, as shown in FIG. 9D, lamp annealing was performed at 1500 ° C. for 10 seconds in an argon gas atmosphere to react the iron with the diamond protrusions.

[0164] Further, using a re-scribe ion etching apparatus, argon (Ar) 80 sccm, oxygen (O ₂ )
20 sccm, 13.56 MHz RF power 300 W
Etching for 60 minutes under the conditions of
About m was removed. Under these conditions, the diamond reacts with iron (convex part) more than the unreacted part (concave part).
The etching rate was 10 times faster. Further, SiO ₂ was removed to obtain a smooth diamond surface as shown in FIG. 9 (e). When the smoothness of the diamond surface thus obtained was measured, R _max was 0.1 μm or less.

[0165]

As described above, according to the present invention, after forming a flat film made of a material different from that of the diamond on the surface of diamond; conditions under which both the diamond and the film can be etched by dry etching. Below, a method of flattening a diamond is provided which smoothes the surface of the diamond by removing the irregularities on the coating and the diamond surface.

By using such a flattening method, the surface can be flattened in a non-contact manner unlike the conventional mechanical polishing such as skiff polishing. Therefore, the material of the substrate, the amount of warpage, the area, the thickness, etc. It is possible to satisfactorily carry out mirror finish polishing or flattening on various diamond surfaces without substantially limiting the state of the substrate.

According to another embodiment of the present invention, a liquid coating material containing a material different from the diamond is dropped on the surface of the diamond to cure it, thereby forming a coating film having a spherical surface on the diamond; Provided is a method for polishing a diamond, which comprises removing the irregularities of the coating film and the diamond surface to obtain a spherical diamond surface under the condition that both the coating film and the diamond can be etched by etching. .

In the above-described diamond flattening method or polishing method, it is possible to sufficiently deal with flattening or polishing of a larger area diamond by using a large dry etching apparatus.

According to such a diamond flattening method or polishing method, a diamond surface having extremely excellent smoothness can be obtained. Therefore, it is possible to obtain a diamond surface having a level not possible on a conventional diamond surface obtained by mechanical polishing. Ultrafine processing can be performed on the diamond surface. Further, according to the present invention, since the polishing process is greatly simplified as compared with the conventional mechanical polishing, it is possible to efficiently reduce the cost, and it is industrially sufficiently advantageous in the planarization method or polishing method. Can be provided.

By using the above-described diamond polishing method, light can be transmitted to a wavelength range that cannot be obtained by materials other than diamond, that is, an ultraviolet range (wavelength of 225 nm or less), and the thermal conductivity is high. It is possible to obtain a highly reliable diamond lens.
In particular, the polishing method of the present invention can be suitably applied to the formation of microlenses.

Further, according to another aspect of the present invention, a first step of forming a coating film made of a material different from that of the diamond on the surface of the diamond and flattening the coating film; Provided is a method for flattening a diamond, which comprises a second step of implanting ions into the diamond; and a third step of removing the coating and removing a diamond portion modified by the ion implantation from the diamond. It

Such a diamond flattening method is described in 5
It can be suitably applied to the production of an electro-optical component requiring a stricter flatness of 0 Å or less (in particular, a heat dissipation substrate for LSI or the like that can be used for a high output semiconductor laser or the like).

Further, according to another aspect of the present invention, when flattening the diamond surface by the dry method, the reduction rate of the convex portion of the diamond surface is set relatively to the reduction rate of the concave portion of the diamond surface. A method of diamond flattening is provided.

According to such a diamond flattening method, it is possible to provide a substrate for electronic devices, which is made of polycrystalline or single crystal diamond and has a smooth surface.

[Brief description of drawings]

FIG. 1 is a schematic side sectional view showing an embodiment of a diamond polishing method of the present invention.

FIG. 2 is a schematic side sectional view showing another embodiment of the diamond polishing method of the present invention.

FIG. 3 is a schematic side sectional view showing still another embodiment of the diamond polishing method of the present invention.

FIG. 4 is a schematic side sectional view showing still another embodiment of the diamond polishing method of the present invention.

FIG. 5 is a schematic side cross-sectional view showing one embodiment of the diamond flattening method of the present invention in the order of steps.

FIG. 6 is a schematic side sectional view showing one embodiment of the diamond flattening method of the present invention in the order of steps.

FIG. 7 is a schematic side sectional view showing another embodiment of the diamond flattening method of the present invention in the order of steps.

FIG. 8 is a schematic side sectional view showing another embodiment of the diamond flattening method of the present invention in the order of steps.

FIG. 9 is a schematic side cross-sectional view showing still another embodiment of the diamond flattening method of the present invention.

[Explanation of symbols]

1 ... Substrate, 2, 10, 20, 51 ... Diamond, 3,
11, 30 ... Coating, 4, 20, 25 ... Diamond surface, 12, 14 ... Diamond lens, 35, 36 ... Coating surface, 40 ... Implanted ion, 45 ... Diamond altered portion, 51 ... Diamond substrate, 52 ... Sacrificial layer, 100 ...
Regions where the film thickness is large, 105 ... Regions where the film thickness is small.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Shikada 1-1-1 Kunyokita, Itami City, Hyogo Prefecture Sumitomo Electric Industries, Ltd. Itami Works

Claims (20)

[Claims] 1. When flattening a diamond surface by a dry method, the reduction rate of the convex portion of the diamond surface is
A method for flattening a diamond, which is characterized in that the rate of reduction of recesses on the surface of the diamond is made relatively higher. 2. A single crystal or polycrystalline diamond is used as the diamond; a flat sacrificial layer is formed on the diamond; the sacrificial layer is uniformly etched to expose convex portions of the diamond surface; The method for flattening a diamond according to claim 1, wherein impurities are attached to the protrusions and annealed to react the impurities with the protrusions; and then the protrusions are removed. 3. A film based on spin-on-glass or tetraethoxysilane (TEOS) is used as the sacrificial layer,
The method of planarizing a diamond according to claim 2, wherein the sacrificial layer has a thickness of 0.1 to 1.0 μm. 4. A metal selected from iron, nickel, manganese, cerium, or lanthanum is used as the impurity, and at a temperature of 500 to 2000.degree.
The diamond flattening method according to claim 2, wherein a reaction layer having a thickness of 0.1 to 1 μm is formed on the diamond surface by reacting the diamond surface protrusions with the impurities by annealing for 30 minutes. 5. A metal selected from iron, nickel, manganese, cerium, or lanthanum is used as the impurity,
The method for flattening a diamond according to claim 2, wherein the annealing is performed after introducing the metal into the convex portion of the diamond surface by ion implantation. 6. The sacrificial layer has a thickness of 0.1% based on spin-on-glass or tetraethoxysilane (TEOS).
1 to 1.0 μm film is used; and as the impurities,
500 to 2000 in vacuum using a metal selected from iron, nickel, manganese, cerium, or lanthanum.
The flatness of diamond according to claim 2, wherein a reaction layer having a thickness of 0.1 to 1 μm is formed on the diamond surface by reacting the diamond surface protrusions with the impurities by annealing at a temperature of ℃ for 1 to 30 minutes. Chemical method. 7. A metal selected from iron, nickel, manganese, cerium, or lanthanum is used as the impurity, and the metal is introduced into the diamond surface protrusions by ion implantation; The diamond flattening method according to claim 2, wherein a reaction layer having a thickness of 0.1 to 1 μm is formed on the diamond surface by reacting the diamond surface protrusions with the impurities by annealing at a temperature for 1 to 30 minutes. . 8. The thickness of the sacrificial layer based on spin-on-glass or tetraethoxysilane (TEOS) is 0.1.
1 to 1.0 μm film is used; and a metal selected from iron, nickel, manganese, cerium, or lanthanum is used as the impurity, the metal is introduced into the diamond surface protrusion by ion implantation, and then the annealing is performed. The method for flattening a diamond according to claim 2, wherein 9. The sacrificial layer has a thickness of 0.1% based on spin-on-glass or tetraethoxysilane (TEOS).
1 to 1.0 μm film is used; a metal selected from iron, nickel, manganese, cerium, or lanthanum is used as the impurity; and a vacuum is applied after introducing the metal into the diamond surface convex portion by ion implantation. Inside 500 ~
By annealing the diamond surface protrusions and the impurities by annealing at a temperature of 2000 ° C. for 1 to 30 minutes,
The diamond flattening method according to claim 2, wherein a reaction layer having a thickness of 0.1 to 1 μm is formed on the diamond surface. 10. The method of flattening a diamond according to claim 1, wherein the rate of reduction of the recess is reduced by applying compressive strain to the recess on the surface of the diamond. 11. The method according to claim 10, wherein a sacrificial layer containing a predetermined amount of impurities is used as the sacrificial layer, and after the convex portions of the diamond surface are exposed and annealed, the impurities are mixed into the concave portions of the diamond surface. Diamond flattening method. 12. The method of planarizing a diamond according to claim 11, wherein boron is used as the impurity. 13. A flat film made of a material different from that of the diamond is formed on the surface of the diamond, and then the film and the diamond surface of the diamond are formed under a condition in which both the diamond and the film can be etched by dry etching. A method for flattening a diamond, which comprises removing irregularities to smooth the surface of the diamond. 14. A coating material is formed on the diamond by dropping a liquid coating material containing a material different from the diamond onto the surface of the diamond and spin coating.
4. The method for flattening diamond according to item 3. 15. A coating material having a spherical surface is formed on the diamond by dropping a liquid coating agent containing a material different from the diamond onto the surface of the diamond and curing the coating material, and then the coating film and the diamond are dry-etched. A method for polishing diamond, characterized in that the spherical surface is obtained by removing the irregularities on the coating film and the diamond surface under conditions capable of etching both of the above. 16. A first step of forming a flat film made of a material different from that of the diamond on the surface of diamond, a second step of ion-implanting diamond through the film, and the step of forming the film. And a third step of removing, from the diamond, the diamond portion that has been altered by the ion implantation and is removed. 17. The method according to claim 16, wherein after the third step, the first step, the second step, and the third step are sequentially repeated. 18. The diamond planarization method according to claim 16, wherein the coating film is made of a resist containing an organic material as a main component. 19. The diamond flattening method according to claim 16, wherein the coating is a coating formed by using a sol-gel method. 20. The coating according to claim 16, wherein in the ion implantation, the blocking cross section of the diamond with respect to the implanted ions and the blocking cross section of the coating with respect to the implanted ions are substantially equal to each other. Flattening method of diamond.