JPS61151097A - Production of diamond thin film with smooth surface - Google Patents

Abstract

PURPOSE:A thin film of diamond is formed on a base plate of Si mirror wafer with fine scratches, then the base plate is dissolved off to enable easy and inexpensive production of diamond thin films with a desired size and smooth surfaces. CONSTITUTION:A base plate of Si mirror wafer is dipped in water in which fine particles of diamond with average particle size of 1-2mum and ultrasonic vibration is applied for 10-30min to form scratches of less than 0.1mum depth and width thereon whereby an Si-mirror wafer base plate with fine scratches. Then, the base plate is placed in a microwave plasma space to allow a diamond thin film to grow thereon under conditions of CH4/H2 gas atmosphere at 1:99 volume ratio, 850 deg.C at the base plate and 30Torr pressure for 5-10hr. Then, the base plate is dissolved off with HF or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a diamond thin film with a smooth surface.

[Conventional technology]

Diamond has a smooth surface and is wear resistant! A wear-resistant sliding surface 9 is used, for example, as a head of a video disk.

Conventionally, to obtain a smooth diamond surface, diamond particles are jet-polished to obtain a surface of rare size. However, diamond is the hardest substance, and polishing requires co-printing, which takes a long time. 1 Also, if you try to get a large surface.

The diamond that can be obtained must be of a size commensurate with the size, and it will be an extremely high-quality diamond.

By the way, recently 1, for example, JP-A-58-91100゜58
-110494.59-3098, etc., a method has been developed to deposit and grow diamond-like compounds on substrates such as 8i, Mo, Cu, etc. with high melting points, sapphire, quartz, WC, etc. ing. In other words, the above-mentioned substrate is made into a mirror surface, and after surface treatment is performed by applying fine hot water using diamond abrasive grains, hydrogen or hydrogen and carbon dioxide gas diluted with an inert gas such as Ar are brought into contact with each other in plasma. Then, diamond fine particles are deposited on the substrate surface, and after 2 to 5 hours, the fiI1. A wedge-shaped diamond with fine grains is obtained. This thin film diamond is produced by a relatively simple manufacturing method, and a film with the same area as the substrate can be obtained, but the growth plane is the (111) plane.

(Since the 1003 planes are formed by growing in random directions, as a result, irregularities of 1 to 5 μm are formed on the shallow growth plane.
In view of the above-mentioned circumstances, the T-invention aims to create a smooth diamond surface with a promising area for agricultural fields by synthesizing diamond using the CVD method. The purpose is to provide the #yun that can be obtained.

[Means for solving problems]

The invention was made to solve the above-mentioned problems, and its feature lies in the fact that it takes advantage of the mirror surface of the substrate. A small corner,
Fine scratches with a depth of 0.1 μm or less are made on the surface of the ZSI mirror wafer substrate, and diamond is deposited by CvL to form a diamond thin film, and the substrate on which this diamond thin film is formed. The non-invention lies in the process for producing a diamond/de thin film with a smooth texture in which the diamond thin film is dissolved by fluorocarbons, etc.
Since it is dissolved by arsenic acid, the surface of the diamond film that is in contact with the substrate is exposed, and this exposed surface becomes the same smooth surface as the substrate surface.

[Specific contingency of invention]

The substrate used in the present invention is suitable for CVD diamond synthesis.
All of the above-mentioned high-melting-point alloys and compounds used in diamonds can be used for long-term use, but Si in particular has a small difference in thermal expansion coefficient from that of diamond, so it does not crack during disposal.
Further, mirror-finished wafers for semiconductor use have the advantage of being easily available, and are therefore preferable.

To deposit diamond on the Si wafer surface 1
It is said that polishing the surface with diamond abrasive grains of 1 to 10 μm and creating small scratches is usually considered to be a good method.

However, when observing the σ] long Itl created using this method and melting the Si side of the material using HF, it appears that unevenness caused by scratches during polishing remains on the replica surface. I can't say it's a gentle side. However, it is necessary to create effective scratches for the growth of diamond, although it is not very deep.To do this, we need to improve the surface treatment.
In order to disperse diamond grains as thin as μ[n in water, an 8i mirror wafer was placed in the water, and the entire body was subjected to ultrasonic vibrations for 10 minutes.
It takes ~30 minutes. This process makes it possible to create minute scratches on the entire surface that can be easily identified with a high-magnification SEM.

The conditions for this device for depositing diamonds are Tsutomi's C.
vL) @'s diamond synthesis method is adopted as is.

Synthesis conditions include, for example, raw material gas C)1. /H.

: 1vo1/99vol, substrate temperature 850°C Royal Sword: 3
It should be done at 0 Torr and with microwave excitation. After 5-10 hours of diamond thin film growth.

70 Substrate-e) When melted by IF, the surface in contact with the substrate becomes a replica of the substrate and becomes smooth, but the residual stress σ) causes the diamond film to curve.

To obtain a smooth and uncurved diamond surface.

The growth surface of the diamond film is not soaked with H1I' water.

After bonding the flat substrate with an adhesive that does not soak in lfI'', the substrate is deweighted with HF.

〔Example〕

Next, the invention will be explained by showing examples.

“Example 1” 1 to 2 μσ? An 8t mirror wafer that had been ultrasonically vibrated within diamond abrasive grains (2wt%) for 20 minutes was placed in a microwave plasma space and heated to C1-1,/H.

When a reaction gas having a volume of 1/99 was flowed at 3 Q Torr for 5 hours, a diamond film with a thickness of 4 μm was obtained. Apply fluorine-based resin to the surface of this diamond film, and
After pasting the iC temporary, dissolve the board in 1-1F water,
Even when observed with SMM, a smooth diamond surface was obtained.

"Example 2".

A diamond flat surface was prepared in exactly the same manner except that diamond abrasive grains having an average particle diameter of 2 μm were used for surface treatment, and polishing was carried out using a conventional method. On this surface, protrusions of 0.1 to 0.2 μm are left, and although it appears to be a smooth surface, it is not a smooth surface according to SEM, and z0
It was clearly a replica of the scratches left during polishing.

"Example 3" Same as Example 1 except that diamond precipitation was carried out for 20 hours.
In the same way as the diamond film.

Is this a substrate with HF water as is? Dissolved, thickness = 20μm
Obtain a diamond film of Although this film is slightly curved due to residual stress, the surface on the wafer side is a mirror-like smooth surface.

〔Effect of the invention〕

The manufacturing method of the diamond # film with a smooth surface according to the present invention is as follows:
Since a diamond thin film deposited by the VD method is used, it is an easy and reliable method that can obtain the desired area with i+li.

Claims (1)

[Claims] Diamond is deposited on the surface of a Si mirror wafer substrate with minute scratches of 0.1 μm or less in depth and width to form a diamond thin film, and the substrate on which this diamond thin film is formed is dissolved and removed. A manufacturing method for diamond thin films with a characteristic smooth surface.