JPH1030178A - Sputtering method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the formation of coating having a certain thickness even in mass- production by estimating the coating forming rate from the measured value of discharge voltage or discharge current. SOLUTION: With attention to the fact that the change of the shape of a target gives influence on discharge voltage, discharge current and coating forming rate, by measuring the change of discharge voltage or discharge current, the change of coating forming rate is estimated, and coating forming conditions, mainly, coating forming time is decided. Concretely, by allowing the relation between the discharge voltage and coating forming rate to closely resemble in the relation of direct proportion, the coating forming rate is estimated. Or the relation between the discharge voltage or discharge current and the coating forming rate is previously measured, and based on the measured result, the coating forming rate is estimated from the discharge voltage or discharge current. namely, data A in the initial stage in the use of the target are recorded in a data preserving means, then, in the process of the subsequent coating formation, the discharge voltage is measured and is inputted into an arithmetic means to allow the relation between the voltage and coating forming rate to closely resemble in the relation of the direct proportion, and based on the data A, the coating forming time is decided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a sputtering method and apparatus for depositing a thin film on a substrate.

[0002]

2. Description of the Related Art A two-electrode sputtering method widely used in the past will be described. The device configuration is shown in FIG.
Referring to FIG. 2, a target 22 and a substrate 23 supported by a substrate support (not shown) are opposed to each other in a vacuum vessel 21 connected to a ground potential. The target 22 is set on a target holder 24.

[0006] A power supply 25 is connected between the target 22 and the vacuum vessel 21. The target 22 and the target holder 24 are insulated from the vacuum vessel 21 by an insulator 26. Magnets 27 and 28 are arranged in the insulator 26 so as to form an electronic trap near the surface of the target 22. 29 is an exhaust port, 30 is a gas inlet, and 31 is generated plasma.

[0004] A description will be given of a sputtering method using a sputtering apparatus having the above-described configuration, taking as an example a case where an aluminum film is automatically formed on a plurality of glass substrates. The target 22 is made of aluminum and the substrate 23 is made of glass. Exhaust port 2
After evacuating the air in the vacuum vessel 21 from 9 and evacuating the inside of the vacuum vessel 21 to a high vacuum, an argon gas is introduced from the gas inlet 30 to make the gas pressure in the vacuum vessel 21 several mTorr. When a high voltage is applied by the power supply 25 in the above state, plasma 31 is generated near the surface of the target 22. Positive argon ions in the plasma 31 enter the target 22 at a negative potential, and neutral particles and secondary electrons are emitted at that time. The secondary electrons collide with gas molecules and ionize the gas molecules. Neutral particles are substances in the target 22, and the particles
Deposits on it to form a thin film. When a film having a predetermined thickness is formed on the substrate 23, the supply of power from the power supply 25 is stopped. After that, the substrate 23 is changed from a film-formed one to a non-film-formed one by a substrate exchange means (not shown), and the same operation is repeated. Here, in order to control the film thickness,
It is necessary to determine the film formation time after knowing the film formation rate by some method.

However, when mass production is performed by the above sputtering method, when the target 22 is eroded,
Since the shape of the target surface changes from FIG. 7A to FIG. 7B, there is a problem that the discharge characteristics change and the deposition rate also changes.

Therefore, conventionally, a method has been adopted in which the film-forming speed is measured by sampling as needed, and the film-forming time is determined according to the measurement result, so that the film thickness of each substrate 23 is kept constant. There is also known a method in which a quartz oscillator is installed near the substrate 23, the film thickness on the substrate 23 is estimated from a change in the oscillation period of the oscillator, and the film forming time is controlled.

[0007]

However, in the above-mentioned conventional method, there is a problem that sampling is required, manual labor is required for this, and production efficiency is lowered. In addition, the method using a quartz oscillator is described in Target 2 below.
Target 2 that is scattered by sputtering when 2 is consumed
2 changes the directivity of the substance in 2 and changes the correlation between the film thickness on the quartz oscillator and the film thickness on the substrate 23. Therefore, this method is not suitable for mass production and requires a special device. There was a problem of becoming.

In view of the above-mentioned conventional problems, the present invention does not require sampling during use of a target or a special apparatus, and a sputtering method and apparatus capable of forming a film having a constant thickness on a substrate even in mass production. It is intended to provide.

[0009]

According to the sputtering method of the present invention, when sputtering is performed, a discharge voltage or a discharge current is measured, a change in the film forming rate is estimated from a change in the measured value, and a film forming condition is determined. To decide. That is,
Paying attention to the fact that the change in the target shape affects the discharge voltage, discharge current, and deposition rate, the change in the deposition rate is estimated by measuring the change in the discharge voltage or discharge current. It determines the film time.

[0010] Specifically, the measurement object is to measure the discharge voltage or discharge current with the discharge power constant, or to measure the discharge current with the discharge voltage constant, or to measure the discharge voltage with the discharge current constant. I do.

Specifically, the deposition rate is estimated by approximating the relationship between the discharge voltage and the deposition rate in a direct proportional relationship, or by previously estimating the relationship between the discharge voltage or discharge current and the deposition rate. The relationship is measured, and the film forming speed is estimated from the discharge voltage or the discharge current based on the measurement result.

Further, in the sputtering apparatus of the present invention, a substrate and a target made of the same material as a film to be formed are installed in a vacuum vessel provided with an exhaust port and a gas introduction port so as to face each other. , Place a magnet near the target,
A power source for applying a voltage is provided between the vacuum vessel and the target, a means for measuring a discharge voltage or a discharge current is provided, and a change in a film forming rate is estimated from a change in a value measured by the measuring means to determine a film forming condition. A film condition determining means is provided.

The film forming condition determining means stores data relating to the relationship between the measured value of the measuring means and the film forming speed, and determines the film forming time from the data stored in the data storing means and the value measured by the measuring means. It can be constituted by arithmetic means.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a sputtering method according to a first embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, a target 2 and a substrate 3 supported by a substrate support (not shown) are arranged opposite to each other in a vacuum vessel 1 connected to a ground potential. The target 2 is set on a target holder 4. A power supply 5 is connected between the target 2 and the vacuum vessel 1. The target 2 and the target holder 4 are insulated from the vacuum vessel 1 by an insulator 6. Magnets 7 and 8 are arranged in the insulator 6 so as to form an electron trap near the surface of the target 2. 9 is an exhaust port of the vacuum vessel 1, and 10 is a gas inlet. Reference numeral 11 denotes a voltmeter for detecting a discharge voltage, 12 denotes data holding means, 13 denotes arithmetic means, and 14 denotes generated plasma.

In this embodiment, aluminum is used for the target 2 and glass is used for the substrate 3, and 3500 ° is deposited on 3600 glass substrates 3 (the allowable range of the film thickness distribution is ± 350
I) A film having a thickness of の) is to be formed. The discharge power was kept constant at 4 kW.

The film forming process will be described.
After replacement, pre-sputter is performed. This pre-sputtering is necessary to remove the oxidized target surface by sputtering. After the pre-sputtering, the film formation rate is measured by sampling, and the discharge voltage is measured by the voltmeter 11. In one example of the present embodiment, 1989 ° /
s, 475.3 V (point A in FIG. 2A). This data is recorded in the data holding means 12 as a target use initial data ID. Thereafter, a film is formed by sputtering. At this time, the discharge voltage is measured by the voltmeter 11, and the measured value is input to the calculating means 13. And
The calculation means 13 approximates the relationship between the discharge voltage and the film formation speed as a direct proportional relationship, and determines the film formation time based on the target use initial data ID.

In order to form a film having a thickness of 3500 °, it can be determined by calculating the following formula by the calculating means 13: film forming time (minute) = 836.4 / discharge voltage (V).

Films were formed on 3600 substrates 3 by the above method. FIG. 2 shows the relationship among the number of substrates, discharge voltage, and film formation time.
FIG. 2A shows the relationship between the number of substrates and the film thickness. As can be seen from FIG. 2, in the present embodiment, the change in the film forming speed is corrected by changing the film forming time.
The maximum value of the film thickness distribution between the substrates according to the present embodiment is 3
765 °, the minimum value is 3500 °, which satisfies the allowable range of ± 350 °.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows the configuration of the used device. The device configuration is basically the same as that of the first embodiment shown in FIG. 1, except that the data recorded in the data holding means 12 is the data FD from the initial use of the target to the end of its life. That is, the difference between the present embodiment and the first embodiment is that in the first embodiment, the film forming speed is estimated from the discharge voltage by approximating the relationship between the discharge voltage and the film forming speed in a direct proportional relationship. The present embodiment is characterized in that the relationship between the discharge voltage and the deposition rate up to the target life is measured in advance, and the deposition rate is estimated from the discharge voltage based on the measurement result.

The data FD from the initial use of the target to the end of its life will be described.
Sputtering was performed on the target 2 having a thickness of 12 mm until the erosion depth became 10 mm, and the deposition rate and discharge voltage were measured as needed. FIG. 4A shows the relationship between the integrated power, the discharge voltage, and the deposition rate, and FIG. 4A shows the relationship between the discharge voltage and the deposition rate.
(B). In this measurement, since the deepest part of the target erosion reached a depth of 10 mm at the point of 350 kWh of integrated power, this point was regarded as the life of the target. In the present embodiment, the relationship between the deposition rate and the discharge voltage is expressed as follows: deposition rate (Å / s) = 2.88 × discharge voltage (V) +62
0 was approximated by a linear expression. This equation is used as the data FD from the initial use of the target to the end of the life of the target.
To record. Thereafter, a film is formed by sputtering. At this time, the discharge voltage is measured by the voltmeter 11 and the measured value is input to the calculating means 13.

In order to form a film having a thickness of 3500 °, data FD from the initial use of the target to the end of its life is used.
And a measurement value from the voltmeter 11 to calculate
It can be determined by calculating the following equation: film formation time (min) = 3500 / (2.88 × discharge voltage (V) +620).

When a film of 3500 ° is formed on 3600 substrates by this method for determining a film forming time, the number of substrates and the discharge voltage,
FIG. 5A shows the relationship with the film formation time, and FIG. 5B shows the relationship between the number of substrates and the film thickness. FIG. 5 shows that the accuracy of controlling the film thickness of each substrate is improved as compared with the first embodiment.

In the above embodiment, the film forming time is determined by monitoring the discharge voltage while keeping the discharge power constant. However, the discharge current is monitored by keeping the discharge voltage constant, or the discharge current is monitored by keeping the discharge current constant. The film formation time may be determined by a method such as monitoring the voltage.

[0025]

According to the sputtering method and apparatus of the present invention, as is apparent from the above description, the film forming speed is estimated from the discharge voltage or discharge current during film formation and the film forming time is determined. It is possible to form a film having a constant thickness in mass production without requiring any operation such as sampling during automatic continuous film formation and without requiring a special device such as a quartz oscillator. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an apparatus configuration of a first embodiment in a sputtering method of the present invention.

FIG. 2 is a graph showing a result according to the same embodiment.

FIG. 3 is a schematic configuration diagram showing an apparatus configuration of a second embodiment in the sputtering method of the present invention.

FIG. 4 is an explanatory diagram of data recorded in a data holding unit in the embodiment.

FIG. 5 is a graph showing a result according to the same embodiment.

FIG. 6 is a schematic configuration diagram showing an apparatus configuration in a conventional sputtering method.

FIG. 7 is an explanatory diagram of a change in surface shape due to erosion of a target.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Target 3 Substrate 5 Power supply 7 Magnet 8 Magnet 9 Exhaust port 10 Gas inlet 11 Voltmeter 12 Data holding means 13 Calculation means

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Masafumi Okamoto 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (9)

[Claims] A substrate, a film to be formed, and a target made of the same material are installed in a vacuum container so as to face each other, a magnet is arranged near the target, and a predetermined vacuum is applied to the inside of the vacuum container. In a sputtering method in which a gas is introduced while maintaining the pressure and a voltage is applied between the vacuum container and the target, and a substance in the target is formed on the substrate, a discharge voltage or a discharge current is applied when sputtering is performed. Is measured, and a change in a film formation rate is estimated from a change in the measured value to determine film formation conditions. 2. The sputtering method according to claim 1, wherein a film forming time is determined as a film forming condition. 3. The sputtering method according to claim 1, wherein the discharge voltage or the discharge current is measured while keeping the discharge power constant. 4. The sputtering method according to claim 1, wherein the discharge current is measured while keeping the discharge voltage constant. 5. The sputtering method according to claim 1, wherein the discharge voltage is measured while keeping the discharge current constant. 6. The method according to claim 1, wherein the film forming speed is estimated by approximating the relationship between the discharge voltage and the film forming speed in a direct proportional relationship, and the film forming time is determined. Sputtering method. 7. A method of measuring a relationship between a discharge voltage or a discharge current and a deposition rate in advance, estimating a deposition rate from the discharge voltage or the discharge current based on the measurement result, and determining a deposition time. The sputtering method according to claim 1, wherein: 8. A substrate, a film to be formed and a target made of the same type of material are placed facing each other in a vacuum vessel provided with an exhaust port and a gas inlet, and a magnet is arranged near the target. Then, a power supply for applying a voltage between the vacuum vessel and the target is provided, a discharge voltage or discharge current measuring unit is provided, and a change in a film forming speed is estimated from a change in a measured value of the measuring unit to determine a film forming condition. A sputtering apparatus, comprising: means for determining film forming conditions. 9. A film forming condition determining means for storing data relating to a relationship between a measured value of the measuring means and a film forming speed, and a film forming time based on data held by the data holding means and a value measured by the measuring means. 9. The sputtering apparatus according to claim 8, further comprising a calculating means for determining.