JP2001307390A - Method and mechanism for sputtering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that film thickness increases more than needed and film thickness uniformity between disks in not in a normal rage when number of times that a disk mounted on a rotary body passes over target is increased as a means for adjusting film thickness corresponding to a decrease in filming rate, as to a sputtering device which forms a film on the disk mounted on the rotary body when the disk passes in front of the target plural times. SOLUTION: An integral discharging time and the quantity of a decrease in filming rate which are previously measured and the rotating speed of the rotary body 4 and the value of a decrease in filming rate are inputted to an arithmetic circuit 13 to obtain an integral discharging time when a film is formed on the disk and always monitor it; when the timing where the filming rate of the target 3 begins decrease is detected, the rotating speed of the rotary body 4 is obtained, the rotating speed of a motor 5 which drives the rotary body 4 so that the film thickness becomes constant is computed, and the value is supplied as a new rotating speed command value 9 for the motor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering method and an apparatus for forming a film on a disk mounted on a rotating body driven by a motor when the disk passes a front surface of a target a plurality of times in an optical disk manufacturing apparatus and the like.

[0002]

2. Description of the Related Art FIG. 3 shows a mechanism of a conventional sputtering apparatus. In FIG. 3, reference numeral 1 denotes a vacuum chamber for generating plasma to form a film; In order to form a film, targets 4 arranged at regular intervals in parallel with the disk surface, 4 is a rotating body for mounting the disk 2 and passing the front of the target 3 at a constant speed, 5 is rotating the rotating body 4 6 and 7 are gears for transmitting the rotation of the motor 5 to the rotating body 4, 8 is for supplying power to the target 3, and
A power supply for generating a plasma state therein, 9 is a rotation command value to the motor 5, and 10 is an output power command value to the power supply 8.

The operation of the sputtering apparatus having such a configuration will be described. A rotating body 4 on which a disk 2 on which a film is to be formed is mounted is rotated at a constant speed by driving a motor 5 via a gear 6 and a gear 7 in a vacuum chamber 1 maintained at a constant pressure. After that, the output power command value 10 is given to the power supply 8, the power supply 8 is activated, the power is supplied to the target 3, and plasma is generated near the front of the target 3. The plasma forms a film when the disk 2 passes in front of the target 3.

[0004]

In a sputtering apparatus, as the integrated discharge time of a target becomes longer, the film forming rate tends to be lower, and the disk thickness tends to be thinner. At this time, there is a case where the thickness of the disk can be adjusted to a predetermined thickness by lengthening the sputtering time.

[0005] For example, in a sputtering apparatus having a structure in which a film is formed on a disk mounted on a rotating body every time the target is passed a plurality of times in front of the target, the total film thickness to be formed as shown in FIG. The tunability of the film thickness is determined by the ratio of the film thickness formed when the film is passed twice.

In other words, if the ratio of the film thickness formed in a single pass over the target to the total film thickness to be formed is smaller than the desired film thickness uniformity, By increasing the number of times of passing over and lengthening the sputtering time, the film formation rate is decreased and the film thickness is reduced, so that an extra film is formed and a predetermined film thickness can be obtained.

However, if the ratio of the film thickness formed in a single pass over the target to the total film thickness to be formed is larger than the desired film thickness uniformity, Even if the number of times of passing over is increased and the sputtering time is extended, the film thickness cannot be adjusted. For example, when the ratio of the film thickness formed in one pass over the target to the total film thickness is 5% or more, the film thickness uniformity is also 5%.
% Or more, there is a problem that when the film thickness uniformity must be kept within 2 to 3%, it exceeds the normal range.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems. In forming a disk mounted on a rotating body, an output power value of a power supply for supplying power to a target is taken. The integrated discharge time is obtained from the output power value and the output time, and the integrated discharge time is monitored.
Based on the relationship between the accumulated discharge time of the target and the amount of decrease in the film formation rate measured in advance, the timing at which the film formation rate starts to decrease from the monitored accumulated discharge time is detected and measured in advance. Based on the relationship between the rotation speed of the rotating body and the film thickness of the disk, the rotation speed of the rotating body for compensating for the decrease in the film forming rate is calculated and obtained. The rotation speed is controlled.

[0009]

Embodiments of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 11 denotes a feedback value of the output power from the power supply 8, reference numeral 12 denotes a rotation detection sensor for measuring the rotation speed of the rotator 4, reference numeral 13 constantly monitors the integrated discharge time during film formation, When the accumulated discharge time at which the film forming rate starts to decrease reaches, the rotational speed of the rotating body 4 for compensating for the decreased amount from the relationship between the accumulated discharge time measured and stored in advance and the decreased amount of the film forming rate. , And gives a new rotation speed command value to the motor 5.

First, an integrated discharge time and a decrease in the film forming rate, which are measured in advance, are input to the arithmetic circuit 13. This can be obtained, for example, from the relationship shown in FIG. In addition, the rotational speed of the rotating body 4 and the decrease value of the film thickness, which are measured in advance, are input. Then, when a new target is attached, the accumulated discharge time of the target 3 stored in the arithmetic circuit 13 is cleared.

Thereafter, at the same time when the film formation on the disk 2 is started by the apparatus, the integrated discharge time is calculated from the feedback value 11 of the output power from the power supply 8 at that time and the time during which the start signal is output to the power supply 8. And monitor it constantly.

Next, the integrated discharge time constantly monitored,
The timing at which the film formation rate starts to decrease is detected by comparing based on the relationship between the integrated discharge time and the amount of decrease in the film formation rate input in advance.

When the accumulated discharge time at which the deposition rate starts to decrease has been reached, the rotation speed of the rotating body 4 itself is calculated based on the input of the rotation detection sensor 12, and the obtained rotation speed is calculated. , And the rotational speed of the rotating body 4 is reduced so that a predetermined film thickness can be obtained even at a reduced film forming rate based on the rotational speed of the rotating body 4 and the reduction amount of the film thickness which are input in advance. The rotation speed of the motor 5 corresponding to the deceleration amount is calculated and obtained, and a value obtained by subtracting the value from the rotation speed command value 9 which has already been set is obtained as a new rotation speed command value for the motor 5. 9 is given.

[0015]

As described above, according to the present invention, in a sputtering apparatus having a structure in which a disk mounted on a rotating body is formed when a disk passes a plurality of times in front of a target, a total amount of film formation is obtained. Even when the ratio of the film thickness formed during one pass over the target to the film thickness is large, when the film formation rate is reduced, the rotation for compensating for the reduction amount of the film formation rate is performed. Calculate and calculate the rotational speed of the body, find a new rotational speed command value to the motor corresponding to that value,
By giving the new rotation speed command value to the motor, the effect of compensating for the decrease in the film formation rate and obtaining good film thickness uniformity can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a sputtering apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a relationship between a film forming rate and an integrated discharge time.

FIG. 3 is a diagram showing a configuration of a conventional sputtering apparatus.

FIG. 4 is a schematic view of a film formed on a disk.

[Explanation of symbols]

 2 disk 3 target 4 rotating body 5 motor 8 power supply 9 motor rotation speed command value 10 power supply output power command value 13 arithmetic circuit

Claims (2)

[Claims] 1. A step of taking in an output power value of a power supply for supplying power to a target when depositing a disk mounted on a rotating body, and calculating an integrated discharge time from the output power value and the output time of the power supply. Monitoring the integrated discharge time and the film deposition rate from the monitored integrated discharge time based on the relationship between the integrated discharge time of the target and the amount of decrease in the film formation rate measured in advance. Detecting the timing at which the rotating body starts to decrease, and the rotating body for compensating for the amount of decrease in the film forming rate, based on the relationship between the rotating speed of the rotating body and the film thickness of the disk measured in advance. And a step of calculating the rotation speed of the rotating body and controlling the rotating body to the rotation speed. 2. A means for capturing an output power value of a power supply for supplying power to a target when depositing a disk mounted on a rotating body, and obtaining an integrated discharge time from the output power value and the output time of the power supply. Means for monitoring the integrated discharge time, and the film deposition rate from the monitored integrated discharge time based on the relationship between the integrated discharge time of the target and the amount of decrease in the film formation rate measured in advance. Means for detecting the timing at which the rotation of the rotating body starts to decrease, and the rotating body for compensating for the amount of decrease in the film forming rate based on the relationship between the rotational speed of the rotating body and the film thickness of the disk measured in advance. Means for calculating the rotation speed of the rotating body, obtaining a new rotation speed command value for the motor for driving the rotating body corresponding to this value, and determining the rotation speed of the rotating body by the new rotation speed command value. A sputtering apparatus having a means for controlling.