JPH0698334B2 - Film forming method and apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a film forming method and apparatus, and more particularly to a film forming method and apparatus for forming a recording film and a reflective film of an optical disk or the like while moving a substrate.

[Conventional technology]

An optical disk memory that records and reproduces information with a laser beam has excellent characteristics as a large-capacity recording / reproducing apparatus because of its high recording density.

An example of the optical disk memory medium has a structure as shown in FIG. That is, a recording layer 21 made of tellurium selenium alloy or the like is provided adjacent to the substrate 1. The recording laser light is focused and irradiated on the recording layer 21 through the substrate 1,
22 is formed. As the substrate 1, synthetic resin such as polycarbonate, polyolefin, polymethylpentel, acryl, epoxy resin, or glass is used. Usually, pits are normally recorded on the substrate 1 in a concentric or spiral pattern at regular intervals with high accuracy. A guide groove is provided.

When light enters a groove with a width of about the laser beam diameter, the light is diffracted, and the spatial distribution of the diffracted light intensity changes as the beam center shifts from the groove, so this is detected and the laser beam is incident on the center of the groove. The servo system is configured as follows. The width of the groove is usually 0.3 to 1.3 μm, and the depth of the groove is set in the range of 1/20 to 1/4 of the laser wavelength used. A servo system is similarly configured for focusing light.

Information is read by irradiating a laser beam having a power weaker than that at the time of recording so as to pass over the pit 22, thereby detecting a change in reflectance due to the presence or absence of the pit 22.

The recording layer 21 is formed using a sputtering source such as a sputtering method or an evaporation method, or a film forming source such as a vapor source. At this time, the fluctuation of the film thickness of the recording layer 21 affects the fluctuation of the recording sensitivity and the fluctuation of the reflectance, so that it must be controlled to a sufficiently small value or less.

Next, the film forming operation of the conventional film forming apparatus will be described with reference to FIG.

The substrate 1 is mounted on the pallet 2 and the pallet 2 is mounted on the carrier 3
And is evacuated by the vacuum exhaust pump 5 in the vacuum exhaust chamber 4. After reaching the desired vacuum control, pallet carrier 3
2. The whole substrate 1 is moved from the vacuum exhaust chamber 4 to the film forming chamber 6 via a gate valve (not shown). In the film forming chamber 6, the pallet 2 is rotated by the pallet rotation motor 7 via the rotation drive shaft 8.
While rotating, the film is formed on the substrate at a position facing the film forming source 9.

[Problems to be Solved by the Invention]

However, such a conventional film forming method and apparatus as described above has a problem that when a large number of disks are formed into a film, a disk having a reflectance not a predetermined value is produced.
The inventors of the present invention have investigated the cause of this, and found that the rotation of the pallet is uneven, which causes a variation in the thickness of the film formed on the substrate in the pallet.

An object of the present invention is to provide a film forming method and apparatus in which even a bearing of a carrier that causes uneven rotation of the pallet does not vary in the thickness of the film formed on the substrate in the pallet at the end of the film formation. Especially.

That is, the film forming method and apparatus of the present invention have a drawback that the operating rate is poor because the film forming thickness easily varies.

[Means for Solving the Problems] In the film forming method and apparatus of the present invention, a substrate is mounted on a pallet, and the pallet is rotated at a position where a part of the pallet is opposed to a film forming source to form a film. And a means for dividing one round of the pallet into equal intervals and detecting a moving time of each section, a means for accumulating the moving time for each section, and a means for varying the rotation speed of the pallet. It is configured to change the rotation speed of the pallet to form a film so that the moving time accumulated for each section is averaged for each section.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

1 (a) and 1 (b) are a front view and a side sectional view showing an embodiment of the present invention.

The film forming apparatus shown in FIGS. 1 (a) and 1 (b) divides one circumference of the pallet into a plurality of small sections by providing through holes 11 at the outer circumference of the pallet 2 at regular intervals. The light source photodetectors 12 are provided on the front and rear surfaces of the pallet 2 to detect the light passing through the through holes 11 to detect the moving time of each section, and the processing circuit 13 integrates the moving time for each section. To do. The processing circuit 13 determines the magnitude of the travel time accumulated for each section, and in the section where the travel time is long,
By controlling the pallet rotation motor 7 so that the rotation speed becomes faster, the variation in the accumulated moving time in each section is reduced to 1
It was set to be less than the average travel time of times.

By doing so, even if the bearing of the carrier causes uneven rotation of the pallet, there is no variation in the thickness of the film formed on the substrate in the pallet.

In the above-described embodiment, the pallet is provided with a through hole to detect the moving time of each section, but a reflector may be provided on the back surface of the pallet to detect, or a rotary encoder may be attached to the rotary shaft to detect. You may.

〔The invention's effect〕

According to the film forming method and apparatus of the present invention, even if the carrier of the bearing that causes uneven rotation of the pallet is used, the thickness of the film formed on the substrate in the pallet does not vary, so that the operating rate can be improved. There is an effect.

[Brief description of drawings]

1 (a) and 1 (b) are a front view and a side sectional view showing an embodiment of the present invention, and FIG. 2 is an optical disk memory medium manufactured using a conventional film forming method and apparatus of the present invention. 3A and 3B are partial cross-sectional views for explaining FIG.
[Fig. 4] is a front view and a side sectional view showing an example of the related art. 1 ... Substrate, 2 ... Pallet, 3 ... Carrier, 4 ...
Vacuum exhaust chamber, 5 ... Vacuum exhaust pump, 6 ... Film forming chamber, 7
...... Pallet rotation motor, 8 …… Rotation drive shaft, 9 …… Deposition source, 11 …… Through hole, 12 …… Light source photodetector, 13 …… Processing circuit, 21 …… Recording layer, 22 …… Pit . a: Feedback signal.

Claims (2)

[Claims] 1. A substrate is mounted on a pallet capable of changing a rotation speed, and the pallet is rotated at a position where a part of the pallet is opposed to a film forming source, and the pallet
Divide the lap into equal intervals and detect the travel time of each section,
A film forming method in which the moving time is accumulated for each section, and the rotation speed of the pallet is changed so that the moving time accumulated for each section is averaged for each section. Method. 2. A pallet (2) on which a substrate (1) is mounted and which rotates at a position partially opposed to a film-forming source (9), and one lap of the pallet (2) is divided at equal intervals. Detecting means (12) for detecting the traveling time of the section, and integrating means (13) for integrating the traveling time for each section
A speed changing means (7) for changing the rotation speed of the pallet (2); and a rotation speed of the pallet (2) so that the moving time accumulated for each section is averaged for each section. And a control means (13) for changing the film thickness to form a film.