JPH10195647A - Semiconductor producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize low film forming rate by freely changing the ion acceleration of a target while keeping the generation of ion in a constant state in a semiconductor producing method using sputtering method. SOLUTION: The generation of ion for sputtering is executed by supplying high frequency power to a coil 104 wound around the a vacuum chamber 100 from a high frequency power source 112. And the high frequency power source 112 is controlled by a control circuit 114. On the other hand, the acceleration of ion to the target 108 is executed by impressing a voltage to a cathode 106 from a DC power source 116. The DC power source 116 is controlled by a control circuit 118. Then, the low film forming rate is realized by suppressing the acceleration of ion by the control circuit 118 while keeping stable plasma discharge by the control circuit 114 at the time of forming a thin film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor manufacturing apparatus using a sputtering method.

[0002]

2. Description of the Related Art Conventionally, various semiconductor manufacturing apparatuses using a sputtering method have been provided. In this semiconductor device, a plasma discharge is generated by introducing a discharge gas into a vacuum chamber and applying a voltage between the electrodes, and positive ions in the plasma collide with a target arranged on the cathode side, A thin film is formed on a wafer by utilizing a sputtering phenomenon that repels target atoms.

[0003]

In a semiconductor manufacturing apparatus using the above-described sputtering method, generation of plasma discharge for ion generation and acceleration of ions to a target are performed by supplying a DC power to a cathode. It is controlled by a single power supply. However, when forming a film with such a configuration, there is no problem if the film thickness is large, but if the film thickness is small, it is necessary to reduce the film forming speed so as not to deteriorate the film thickness reproducibility. is there. In order to reduce the film formation rate, it is common to lower the applied voltage to the cathode. However, if the applied voltage to the cathode is too low, the plasma discharge itself becomes unstable or cannot be maintained. The problem of disappearing occurs. Therefore, the limit of the low film forming rate is a control level of the applied voltage at which the plasma discharge can be stably maintained.

However, the current low film forming rate is not sufficiently low for the thin film forming required by the process, and the film forming time is short and the film thickness reproducibility is poor. Also,
When the film formation time is short, the film thickness uniformity also deteriorates. This is to rotate the permanent magnet on the back surface of the cathode to obtain good film thickness uniformity by uniformly colliding ions on the target surface, but if the film formation time is short,
This is because a sufficient number of rotations of the magnet cannot be obtained within this time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor manufacturing apparatus capable of freely changing ion acceleration to a target and maintaining a low film forming rate while maintaining ion generation at a constant state. is there.

[0006]

According to the present invention, in order to achieve the above object, in a semiconductor manufacturing apparatus using a sputtering method, an ion generating means for generating ions by plasma discharge in a chamber, and controlling the ion generating means. A second control unit for controlling the ion acceleration unit; a first control unit for accelerating ions generated by the ion generation unit to collide with a target; and a second control unit for controlling the ion acceleration unit. And the ion acceleration means are controlled by independent control means.

In the above-described semiconductor manufacturing apparatus, the ion generation rate at which ions are generated by plasma discharge in the chamber is controlled by controlling the power supply to the ion generation means by the first control means. On the other hand, the acceleration of the ions that collide with the target is performed by controlling the power supply to the ion acceleration means by the second control means. Thereby, the first control means and the second control means can operate independently, and separate power supply control can be performed, so that the ion generation can be maintained in a constant state by a sufficient power supply level. Low-speed film formation can be performed while suppressing ion acceleration to the target. Therefore, when a thin film is formed, the film can be formed over a sufficiently long time, and the reproducibility of the film thickness and the uniformity of the film thickness can be improved.

[0008]

Next, an embodiment of a semiconductor manufacturing apparatus according to the present invention will be described. FIG. 1 is an explanatory view showing an example of a semiconductor manufacturing apparatus using a sputtering method according to the present invention. In this semiconductor manufacturing apparatus, a semiconductor wafer 102 is placed in a vacuum chamber 100, and a high-frequency power is supplied to a coil 104 wound around the outer periphery of the vacuum chamber 100, thereby generating a plasma discharge to generate positive ions. The ions are converted to a cathode (cathode) 10
The thin film is formed on the wafer 102 by colliding with the target 108 disposed on the sixth side to repel target atoms.

The vacuum chamber 100 is electrically grounded, and is supplied with a discharge gas such as argon gas in a vacuum state. This vacuum chamber 100
The upper half in the figure is formed in a cylindrical shape, and a coil 104 is wound around the outer periphery. The semiconductor wafer 102 is disposed inside the vacuum chamber 100 at a lower position in the figure. The semiconductor wafer 102 is installed electrically insulated from the vacuum chamber 100.

The coil 104 has one end connected to a high-frequency power supply 112 via a matching box 110 and the other end grounded. Matching box 110
Is for impedance matching between the coil 104 and the high-frequency power supply 112. In addition, the high frequency power supply 112
Is to generate a plasma discharge in a vacuum chamber 100 into which a discharge gas is introduced by applying a high-frequency voltage to a coil 104 to generate positive ions. That is, in this example, the coil 104 and the matching BOX 11
0, the high frequency power supply 112 constitutes an ion generating means. Then, the high-frequency power supply 112 and the matching BOX 11
0 is controlled by the control device 114 as the first control means. That is, the control device 114 controls the coil 1
A high-frequency voltage applied to the plasma generator 04 is controlled to maintain a stable plasma generation state.

On the other hand, a cathode 106 is provided in the upper part of the vacuum chamber 100 in the drawing.
The target 108 is attached to 06. The cathode 106 is formed in a housing shape, and has a target 108 attached with a screw or the like. Target 10
Numeral 8 is electrically connected to the cathode 106, and is disposed so as to face the internal space of the vacuum chamber 100. The cathode 106 is connected to a cathode terminal of a DC power supply 116, and the voltage level of the DC power supply 116 is controlled by a control circuit 118 as a second control unit. Then, the acceleration of the positive ions to the target 108 is controlled according to the voltage application level to the cathode 106. That is, in this example, the cathode 10
6. The DC power source 116 constitutes an ion acceleration means.

A permanent magnet 120 is provided inside the cathode 106 in a state close to the target 108. The permanent magnet 120 is rotationally driven by a rotational drive mechanism (not shown) via a rotary shaft 120A,
This is for obtaining a uniform collision state of ions to the surface of the target 108.

In the semiconductor manufacturing apparatus having the above configuration, when forming a film, first, the inside of the chamber 100 is evacuated, and then a discharge gas is introduced. Then, the high-frequency power supply 112 is operated by the control device 114 to apply a predetermined high-frequency voltage to the coil 104. Thereby, plasma discharge occurs in the chamber, and ions are generated. Next, the DC power supply 116 is controlled by the control circuit 118,
A DC voltage is applied to the cathode 106 to accelerate ions toward the target and start sputtering.

In such sputtering, the controller 114 controls the high frequency power supply 112 to maintain a sufficient power supply for stable plasma discharge. On the other hand, regarding acceleration of ions, the control circuit 11
The DC power supply 116 can be controlled by 8 to arbitrarily control the speed of ions. Therefore, particularly when forming a thin film, it is possible to suppress the acceleration of ions while maintaining a stable plasma discharge and realize a low film formation rate. As a result, a thin film can be formed in a sufficiently long film formation time,
The film thickness reproducibility and the film thickness uniformity can be improved.

In the above description, the coil 104 is provided on the outer periphery of the chamber 100. However, it is also possible to arrange the coil inside the chamber 100 and supply a high frequency power from the outside. Further, an electromagnet may be provided instead of the permanent magnet 120 described above. Further, the present invention is not limited to a single-chamber apparatus as described above, and can be applied to a multi-chamber apparatus. In addition, a batch-type apparatus for processing a plurality of wafers at a time, and one wafer The present invention can be widely applied to a single-wafer processing apparatus that performs processing one by one.

[0016]

As described above, in a semiconductor manufacturing apparatus using the sputtering method of the present invention, an ion generating means for generating ions by plasma discharge in a chamber, and an ion generated by the ion generating means are accelerated. Ion accelerating means to collide with the target
Independently controlled first and second control means are used for separate control. Therefore, according to the present invention, while maintaining a sufficiently stable plasma discharge by the ion generating means,
It is possible to arbitrarily change the speed of ions by the ion acceleration means. Therefore, it is possible to form a film over a sufficiently long time, particularly when a thin film is formed, and it is possible to improve the film thickness reproducibility and the film thickness uniformity.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a semiconductor manufacturing apparatus using a sputtering method according to the present invention.

[Explanation of symbols]

100 vacuum chamber, 102 semiconductor wafer,
104, coil, 106, cathode, 108, target, 110, matching box, 112, high-frequency power supply, 114, first control device, 116, DC power supply, 118, second control circuit , 120 ... permanent magnet.

Claims (9)

[Claims] 1. A semiconductor manufacturing apparatus using a sputtering method, wherein: an ion generating means for generating ions by plasma discharge in a chamber; a first control means for controlling the ion generating means; Ion accelerating means for accelerating the generated ions to collide with a target, and second control means for controlling the ion accelerating means, wherein the ion generating means and the ion accelerating means are controlled by independent control means. A semiconductor manufacturing apparatus characterized by the above-mentioned. 2. The apparatus according to claim 1, wherein said ion generating means is means for supplying high-frequency power to a coil disposed in said chamber, and said first control means is means for controlling high-frequency power to be supplied to said coil. 2. The semiconductor manufacturing apparatus according to claim 1, wherein: 3. The semiconductor manufacturing apparatus according to claim 2, wherein said coil is arranged on an outer periphery of said chamber. 4. The semiconductor manufacturing apparatus according to claim 2, wherein said coil is arranged on an inner periphery of said chamber. 5. The high frequency power supply for supplying high frequency power to the coil via an impedance matching circuit, wherein the first control means controls the impedance matching circuit and the high frequency power supply. By doing
The semiconductor manufacturing apparatus according to any one of claims 2 to 4, wherein high-frequency power supplied to the coil is controlled. 6. The ion accelerating unit is a unit that supplies DC power to a cathode on which the target is arranged, and the second control unit is a unit that controls DC power supplied to the cathode. The semiconductor manufacturing apparatus according to claim 1, wherein: 7. The ion accelerating means has a DC power supply for supplying DC power to the cathode, and the second control means controls the DC power supply to reduce the DC power supplied to the cathode. 7. The semiconductor manufacturing apparatus according to claim 6, wherein the control is performed. 8. A plasma discharge is generated by introducing a discharge gas into a vacuum chamber and applying a voltage, and positive ions in the plasma are caused to collide with a target disposed on a cathode side, thereby forming target atoms. 5. The semiconductor manufacturing apparatus according to claim 1, wherein a thin film is formed on the wafer by ejecting a thin film. 9. The apparatus according to claim 1, wherein a uniform collision state of the ions to the target surface is obtained by rotating a magnet disposed on the back side of the target. The semiconductor manufacturing apparatus according to the above.