Process for minute processing of diamonds

A process for the minute processing of diamonds which comprises PA1 preparing a substrate; PA1 forming a first buffer layer on the substrate; PA1 forming a second buffer layer, having a higher charge transfer rate than both the substrate and the first buffer layer, on the first layer; PA1 selectively removing the first and second buffer layers to selectively expose the surface of the substrate; PA1 depositing diamonds on the whole surface of the exposed surface of the substrate and the remaining first and second buffer layer; and PA1 removing the by-products formed on the surface of the second buffer layer and surface thereof.

FIELD OF THE INVENTION 
The present invention relates to a process for processing diamonds, more 
specifically, to a process for the minute processing of diamonds. 
BACKGROUND OF THE INVENTION 
As processes for processing diamonds, a process using a laser and a process 
using an ionized beam have been generally used. 
In the process of using a laser, an excimer laser such as KrF or ArF is 
used. The laser operates at a frequency of 50 to 100 Hz, and is used to 
form a deep pattern or a hole on the diamond of 10 .mu.m thickness. 
In other words, an excimer laser such as KrF or ArF is irradiated onto the 
surface of a diamond film under a proper oxygen atmosphere to partially 
remove C clusters by burning. 
In the process of using an ionized beam, the ionized beam is merely used in 
place of the laser mentioned above. 
A desired pattern is formed by irradiating the ionized beam focused on a 
diamond film to remove the unnecessary part of the diamond film. In other 
words, the potential of the ionized beam from a Ga ion source is 
accelerated to a fixed point of about 25 KeV. Then, a desired pattern is 
formed by continuously radiating the Ga ionized beam in one direction onto 
the parts of the diamond film desired to be removed. 
However, the conventional methods of processing diamonds or diamond 
surfaces using the laser or ionized beam techniques mentioned above have 
the following problems: 
First of all, the cost of these techniques is very high because both 
methods require expensive equipment. 
Secondly, the processing time of the method using an excimer laser is long 
and has no relationship between the process and conventional processes for 
manufacturing semiconductors. 
Thirdly, in the case of using an ionized beam, radiation with an ionized 
beam depends on sputtering which causes additional damage. 
SUMMARY OF THE INVENTION 
The object of the present invention is to overcome the above mentioned 
problems and to provide a process for the minute processing of diamonds, 
which is useful in the minute pattern formation of a diamond. 
The process according to the present invention in order to achieve the 
above object comprises the steps of 
preparing a substrate; 
forming a first buffer layer on the substrate; 
forming a second buffer layer on said first buffer layer, said second 
buffer layer having a higher charge transfer rate than the substrate and 
the first buffer layer; 
selectively removing parts of the first and second buffer layers to expose 
predetermined parts of the surface of the substrate; 
depositing diamond on the whole surface of the exposed surface of the 
substrate and the remaining first and second buffer layers; and 
removing by-products formed on the surface of the second buffer layer as 
well as the second buffer layer itself.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The present invention will now be described by referring to the figures 
attached hereto. 
FIGS. 1A to 1C are sectional views showing the process for the minute 
processing of diamonds according to the present invention. 
Firstly, the first buffer layer 22 and the second buffer layer 23 are 
sequentially formed on the substrate 21. The substrate 21 is made of a 
semiconductor material, a nonconductor material or a specific metal. The 
first buffer layer 22 is also formed by using a semiconductor material, 
e.g. silicon, a nonconductor material or a specific metal. As a 
nonconductor material, insulators, an oxide, e.g. SiO.sub.2, a nitride, 
e.g. Si.sub.3 N.sub.4, or a carbide, for example SiC, may be used. As a 
specific metal, Au, W, Ta or Ti may be used. 
According to an embodiment of the present invention, the substrate 21 is 
made of a semiconductor material, the first buffer layer 22 is made of 
nonconductor material, and the second buffer layer 23 is made of a metal 
such as Fe, Pt, Pd, Rh or Ni. As the second buffer layer 23 does not 
satisfy selective growth, it is formed by sputtering. The second buffer 
layer can be described as having a higher electrochemical response rate 
than the first buffer layer and the substrate. 
Then, a photosensitive film (not shown in the figures) is coated on the 
upper side of the second buffer layer 23, in order to form a pattern to 
the part desired to be subject to the crystal growth of the diamond, as 
illustrated in FIG.1B. The second buffer layer 23 and the first buffer 
layer 22 are sequentially etched by using, the pattern-formed on the 
photosensitive film, as a mask. At this time, the second buffer layer 23 
is etched by using an etchant containing a halogen gas such as BCl.sub.3, 
CCl.sub.4, Cl.sub.2, CCeF.sub.3, CF.sub.4, CBCF.sub.3, SF.sub.6, and the 
like. The first buffer layer 22 is also etched by using CF.sub.4 /H.sub.2, 
CHF.sub.3, C.sub.2 F.sub.6, etc., as the etchant. At the time of etching 
the first buffer is layer 22, the layer is overetched to sufficiently 
expose the substrate 21 in order to effect close adhesion with the 
substrate 21. 
Subsequently, diamond is deposited by CVD (Chemical Vapor Deposition). At 
this time, a diamond crystal grows at the contacted portion between the 
substrate 21 and the first buffer layer 22, and diamond soot 24a grows on 
the surface of the second buffer layer. Thus, diamonds grow as a soot on 
certain metals having a high charge transfer rate, e.g. Fe, Pt, Pd, Rh, 
Ni, etc., whereas it grows as a crystal on the surface of other metals, 
e.g. Au, W, Ta, Ti, etc., semiconductors or nonconductors. 
During the CVD of diamond, the temperature should be maintained at 
800.degree. C. or less, e.g. 600 to 800, and the gas used in the 
deposition is a gas composition containing 0.1 to 4% CH.sub.4, 0 to 0.5% 
O.sub.2 with the substantial balance being H.sub.2. 
Subsequently, the diamond soot 24 on the upper side of the second buffer 
layer 23, as well as the second buffer layer itself are sequentially 
removed, as illustrated in FIG.1C. At this time, the diamond soot 24a is 
easily removed by washing due to the weak binding force thereof. 
As described above, the process for the minute processing of diamonds 
according to the present invention is advantageous in that it enables the 
formation of a minute pattern of diamonds which does not require expensive 
equipment and provides a shortened processing time. 
The invention being thus described, it will be obvious that the same may be 
varied in many ways. Such variations are not to be regarded as a departure 
from the spirit and scope of the invention, and all such modifications as 
would be obvious to one skilled in the art are intended to be included 
within the scope of the following claims.