JPH0987835A - Method and device for sputtering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sputtering device free from arcing at a screening electrode. SOLUTION: A screening electrode 4, set at an earth potential, is arranged around a target electrode 11 and a sputtering target 12 disposed on the target electrode 11. When the screening electrode 4 is provided with a potential controller 5 and voltages of electropositive potential and electronegative potential are intermittently superimposed on the earth potential, a plasma 8 can be introduced into the position between the sputtering target 12 and the screening electrode 4. As a result, the electric charge of the insulating material accumulated on the surface of the screening electrode 4 can be removed. It is preferable to intermittently apply a high frequency voltage on the screening electrode 4 because the plasma 8 can be stably maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering technique, and more particularly to a sputtering apparatus and a sputtering method in which abnormal discharge phenomenon during film formation is reduced or eliminated.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a sputtering apparatus for forming a thin film has been used. Referring to FIG. 5, reference numeral 102 is a conventional sputtering apparatus, which has a metal vacuum chamber 103. A target electrode 111 is horizontally provided on the bottom surface of the vacuum chamber 103 via an insulator 105, and a sputter target 112 is arranged on the target electrode 111.

A substrate electrode 113 is provided on the ceiling of the vacuum chamber 103 in parallel with the target electrode 111, and a substrate 114, which is a film formation target, is held on the surface of the substrate electrode 113 facing the sputter target 112. ing.

A power source 115 is applied to the target electrode 111.
Are connected, the vacuum chamber 103 and the substrate electrode 113 are placed at a ground potential, and the power source 115
According to the substrate electrode 113 and the target electrode 11
It is configured so that a high frequency voltage can be applied between

In the vacuum chamber 103, a metallic material is formed around the sputter target 112 and the substrate 114 so that target particles ejected from the sputter target 112 do not adhere to the wall surface of the vacuum chamber 103. An adhesion plate 119 is provided, and like the vacuum chamber 103, the adhesion prevention plate 119 is placed at the ground potential to prevent charged particles from entering.

Further, the vacuum chamber 103 is provided with a gas introducing pipe 116, one end of the gas introducing pipe 116 is connected to a gas piping system provided outside the vacuum chamber 103, and the other end is connected to the gas piping system. Protective plate 119
It is configured so that it can be directly introduced into the inside and the sputtering gas can be directly introduced into the inside of the deposition preventing plate 119.

When forming a thin film of the sputtering target 112 on the surface of the substrate 114, the inside of the vacuum chamber 103 is evacuated and the gas introduction pipe 11 is used.
6, the sputtering gas is introduced, and then the power supply 115 is activated to generate plasma of the sputtering gas on the surface of the sputter target 112, and the surface of the sputter target 112 is sputtered to deposit a thin film on the surface of the substrate 114. Let

In this case, the target particles do not adhere to the inside of the vacuum chamber 103 due to the adhesion preventing plate 119 even when sputtering is performed for a long time to form thin films on the surfaces of many substrates. Therefore, the attachment plate 1
If the maintenance work is performed before the dust generation from 19 becomes a problem and the adhesion-preventing plate 119 is washed or replaced with a new one, a thin film having no film defect can be formed, and the maintenance work is also easy. Therefore, such a sputtering apparatus 102 is widely used in general production sites.

In this sputtering apparatus 102, a shield electrode 104 placed at a ground potential is provided in the vicinity of the target electrode 111, and a discharge is generated between the target electrode 111 and the deposition preventing plate 119. It is supposed not to happen. The distance between the shield electrode 104 and the target electrode 111 is generally set to a very short distance of about several mm because discharge occurs if it is too wide.

However, the sputtering apparatus 1
When 02 is continuously operated for a long time, an insulator is deposited on the non-erosion portion of the surface of the sputter target 112, and such a non-erosion portion is not impacted by ions, and thus is accumulated in the insulator. Electric charge increases, causing a dielectric breakdown phenomenon. It is known that when dielectric breakdown occurs, arcing occurs with the shield electrode 104. It is also known that arcing occurs between the shield electrode 104 and the sputter target 112 even when an insulator is deposited on the shield electrode 104 and charged.

In such a case, if a positive voltage pulse is periodically applied to the target electrode 111, the charge of the insulator deposited on the non-erosion portion can be eliminated, but the insulator deposited on the shield electrode 104 can be eliminated. The electric charge of the shield electrode 104 cannot be eliminated and is generated by dielectric breakdown.
Arching could not be prevented.

In such a case, if the shield electrode 104 is frequently cleaned to remove the attached insulator, the occurrence of arcing can be prevented, but it is complicated to perform such work frequently. In addition, since the operating rate of the sputtering device is reduced, a solution has been desired.

[0013]

SUMMARY OF THE INVENTION The present invention was created in order to solve the above-mentioned disadvantages of the prior art, and its object is to provide a sputtering apparatus and a sputtering method in which arcing does not occur in the shield electrode. is there.

[0014]

In order to solve the above-mentioned problems, the present invention provides a target electrode, a sputter target disposed on the target electrode, and a sputter target disposed around the target electrode and the sputter target. A sputtering device having a shield electrode placed at a ground potential, wherein the shield electrode is provided with a potential control device, and the positive potential and the negative potential are intermittently superposed. Is characterized by.

In that case, it is preferable that the potential control device is configured to apply an intermittent high frequency voltage to the shield electrode.

According to such a configuration of the present invention, since the shield electrode arranged around the sputter target is placed at the ground potential, the target is generated when plasma is generated on the target electrode. No electric discharge occurs between the electrode and the surrounding vacuum chamber or the like placed at the ground potential.

Then, during sputtering, if intermittent positive and negative voltages are superposed on the ground potential of the shield electrode, plasma of sputtering gas is generated between the shield electrode and the target electrode. Be drawn into.

In this case, while the shield electrode is at a positive potential, it drives positively charged particles in the plasma toward the target and draws in electrons, so that the charge of the insulator deposited on the surface of the shield electrode is charged. Can be eliminated, and positive valence electrons in the plasma are attracted while being placed at a negative potential, so that the surface of the shield electrode is cleaned. In that case, the positive potential and the negative potential are not always applied, and since they are applied intermittently, the shield itself is not sputtered.

Further, by intermittently superimposing a high frequency voltage on the ground potential so as to place the shield electrode at a positive potential and a negative potential, even if the space between the shield electrode and the target electrode is narrow, the gap is kept. It is possible to penetrate deep into the plasma.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. Referring to FIG. 1, 2 is a cross-sectional view of an example of the sputtering apparatus of the present invention, which has a metal vacuum chamber 3 which is evacuated by a vacuum pump (not shown). A flat plate-shaped target electrode 11 is horizontally arranged on the bottom surface of the vacuum chamber 3, and a sputter target 12 is provided on the target electrode 11.

A substrate electrode 13 is provided on the ceiling of the vacuum chamber 3 in parallel with the target electrode 11, and a substrate 14 as a film-forming target is held on the lower surface of the substrate electrode 13. And the sputter target 12
And are facing each other.

A cylindrical shield electrode 4 is arranged around the sputter target 12 and the sputter electrode 11, and is attached to the vacuum chamber 3 while being electrically insulated by an insulator 10. ing.

The vacuum chamber 3 is placed at a ground potential, and the target electrode 11 is also connected to the power supply 17 while being insulated from the vacuum chamber 3.
A voltage can be applied between the vacuum chamber 3 and the substrate electrode 13.

When a thin film is formed on the surface of the substrate 14 using the sputtering apparatus 2, the inside of the vacuum chamber 3 is set to a high vacuum state, and then the sputtering gas and the reaction gas (O ₂ gas) are added. Is introduced and the power supply 17 is activated to place the target electrode 11 at a negative potential of several hundreds of volts. Then, plasma 8 is generated in the vicinity of the surface of the sputter target 12, the surface of the sputter target 12 is sputtered, and when reactive DC sputtering is performed, a thin film of an insulator is formed on the surface of the substrate 14.

The shield electrode 4 is provided with a potential control device 5 connected to the ground potential, and the potential control device 5 is provided.
It is connected to the ground potential by direct current by the high-frequency coil 51 of, and is configured so that no discharge occurs between the target electrode 11 and a member placed around the target electrode 11 at the ground potential.

Further, the potential control device 5 has a circuit in which a coupling capacitor 52, a matching box 53, and an RF power source 54 whose voltage can be controlled are connected in series. Inside, the circuit is connected in parallel with the high frequency coil 51. The RF power source 54 was activated to superimpose a high frequency voltage v on the shield electrode 4 as shown in FIG. Here, the high frequency voltage v
The amplitude was set to ± 80 V, the frequency was 40 kHz, the application period was about 1.0 sec, and the application interval was 60 sec.

The state of the plasma 8 when the shield electrode 4 is placed at the ground potential and when the high frequency voltage v is superimposed is shown in FIG. 3 by enlarging the vicinity of the shield electrode 4. Show.

Reference numeral 8 _{1 in} FIG. 3 is the shield electrode 4
Shows the state of plasma when it is placed at the ground potential, and the plasma 8 ₁ does not enter between the shield electrode 4 and the sputter target 12. If such a state is continued, a thin film of an insulator is deposited on the surface of the shield electrode 4 facing the sputter target 12, and arcing occurs.

On the other hand, when the plasma when the high frequency voltage v is superimposed on the ground potential is shown by reference numeral 8 ₂ , the plasma 8 ₂ is drawn between the shield electrode 4 and the sputter target 12. , The plasma 8 ₂
Due to the electrons and charged particles therein, the charge of the insulator thin film deposited on the surface of the shield electrode 4 is eliminated and the surface is cleaned, so that arcing does not occur during sputtering.

The shield electrode 4 described above does not cover the peripheral surface of the sputter target 12 and has an open structure so to speak.
2 The plasma generated on the surface is the sputter target 12
And the shield electrode 4 easily intrudes.

On the other hand, as shown in FIG. 4, in the case where the sputtering device 72 is constructed by providing a shield electrode 74 for covering the peripheral surface of the sputter target 12 in place of the shield electrode 4, when the sputtering device 72 is constructed, Of the plasma is suppressed, and the plasma is less likely to enter between the shield electrode 74 and the sputter target 12. Therefore, the charge of the insulator deposited on the surface of the shield electrode 74 cannot be eliminated, and the generation of arc cannot be prevented.

Although the case of performing reactive DC sputtering has been described above, the present invention is not limited thereto, and can be widely applied to various sputtering methods such as high frequency sputtering and DC sputtering without reaction. You can The voltage applied to the shield electrode is also shown in FIG.
It is possible to use various waveforms without being limited to those shown in FIG.

[0033]

EFFECTS OF THE INVENTION Arc discharge does not occur on the shield electrode, and stable sputtering can be performed. In addition, maintenance work becomes easy.

[Brief description of drawings]

FIG. 1 is a sectional view of an example of a sputtering apparatus of the present invention.

FIG. 2 is a waveform diagram showing an example of a high-frequency voltage superimposed on the shield electrode.

FIG. 3 is a diagram for explaining a plasma state between a shield electrode and a sputtering target.

FIG. 4 is a diagram for explaining the spread of plasma when the peripheral portion of the sputter target surface is covered with a shield electrode.

FIG. 5 is a cross-sectional view of a conventional sputtering device.

[Explanation of symbols]

2 ... Sputtering device 4 ... Shield electrode 11 ... Target electrode 12 ... Sputtering target v ... High-frequency voltage

Claims (4)

[Claims] 1. A sputtering apparatus comprising: a target electrode; a sputter target disposed on the target electrode; and a shield electrode disposed around the target electrode and the sputter target and placed at a ground potential. In addition, a potential control device is provided on the shield electrode, and a positive potential voltage and a negative potential voltage are configured to be superposed intermittently. 2. The sputtering apparatus according to claim 1, wherein the potential control device is configured to apply an intermittent high frequency voltage to the shield electrode. 3. A sputtering method in which a shield electrode is disposed around a target electrode and a sputter target disposed on the target electrode, and the potential of the shield electrode is set to an earth potential to sputter the sputter target. Then, the sputtering is performed by intermittently superimposing a positive potential voltage and a negative potential voltage on the shield electrode. 4. The sputtering method according to claim 3, wherein a high frequency voltage is applied to the shield electrode.