Apparatus for coating a substrate with dielectrics

• US 4,931,169 A
• Filed: 09/28/1988
• Issued: 06/05/1990
• Est. Priority Date: 06/23/1988
• Status: Expired due to Fees

• Current Assignee: Leybold Aktiengesellschaft
• Original Assignee: Leybold Aktiengesellschaft
• Inventors: Latz, Rudolf, Scherer, Michael, Patz, Ulrich
• Primary Examiner(s): Nguyen, Nam X.
• Application Number:
  US07/250,381
• Time in Patent Office: 615 Days
• Field of Search: 204/298 PS, 204/298 GF, 204/298 MS, 204/298 ME, 204/298 FP, 204/298 PM, 204/192.12
• US Class Current: 204/298.11
• CPC Class Codes: C23C 14/0042 Controlling partial pressure or flow rate of reactive or inert gases with feedback of measurements
• CPC Class Codes: C23C 14/0068 characterised by means for confinement of gases or sputtered material, e.g. screens, baffles
• CPC Class Codes: C23C 14/0652 Silicon nitride
• CPC Class Codes: C23C 14/35 by application of a magnetic field, e.g. magnetron sputtering C23C14/3457 takes precedence
• CPC Class Codes: H01J 37/3405 Magnetron sputtering

Abstract

The invention relates to an apparatus for coating a substrate (1) with dielectrics which has a dc current source (10) connected to an electrode (5) which is connected to a target (3) which is being sputtered. The sputtered particles of the target (3) form a compound with an introduced substance which is deposited on the substrate (1). Permeating the target (3) are toroidal maganetic fields whose field lines emerge in the region of magnetic poles from the surface of the target (3). Under the invention an ac voltage source (30) is provided whose output voltage is superimposed on the dc voltage of the dc current source (10). Here, the electrical output of the ac current source (30) which is supplied to the electrode (5) corresponds to 5% to 25% of the output supplied by the dc current source (10) to the electrode (5).

Claims

1. An improved apparatus for coating a substrate with dielectrics, the apparatus having a dc voltage source which is connected to an electrode which in turn is connected to a target which is sputtered and whose sputtered particles form a compound with an introduced substance, the compound being deposited on the substrate, the apparatus further having toroidal magnetic fields permeating the target with field lines emerging in the region of the magnetic poles from the surface of the target, the improvement comprising:

an ac voltage source whose output voltage is superimposed on the dc voltage of the dc voltage source; and

the voltage output of the ac voltage source is coupled to the electrode and equals 5% to 25% of the voltage output supplied to the electrode by the dc voltage source.

2. Apparatus as recited in claim 1, wherein the ac voltage source is a high frequency voltage source.

3. Apparatus as recited in claim 2, wherein the dc voltage source is regulated with respect to current, voltage or output power.

4. Apparatus as recited in claim 1 or 2, wherein the ac voltage output is 10% of the dc voltage output.

5. Apparatus as recited in claim 1, wherein the dc voltage source is coupled to the electrode via first and second inductors.

6. Apparatus as recited in claim 5, wherein between the dc voltage source and the first inductor a capacitor couples the dc voltage source to ground potential.

7. Apparatus as recited in claim 5, wherein between the first inductor and the second inductor a capacitor couples the first inductor to ground potential.

8. Apparatus as recited in claim 1, wherein the ac voltage source is coupled to the electrode via first and second capacitors.

9. Apparatus as recited in claim 1, wherein a first container is provided in which is located a second container having an opening which defines a diaphragm, with the substrate to be coated facing the target through this opening of the second container, and further wherein one or more gases are introduced into the interspace between the first and the second containers.

10. Apparatus as recited in claim 1, wherein the ac voltage source supplies an ac voltage having a frequency of 13.56 MHz.

11. Apparatus as recited in claim 1, wherein the target consists of aluminum and the compound deposited on the substrate consists of Al₂ O₃.

12. Apparatus as recited in claim 1, wherein the target consists of conductive silicon and the compound deposited on the substrate consists of SiO₂.

13. Apparatus as recited in claim 1, wherein the target consists of aluminum and the compound deposited on the substrate consists of AlN.

14. Apparatus as recited in claim 1, wherein the target consists of conductive silicon and the compound deposited on the substrate consists of Si₃ N₄.

15. Apparatus as recited in claim 1, wherein the dc voltage source, when a target of Al, Si or Sn is used, is regulated with respect to voltage.

16. Apparatus as recited in claim 1, wherein the dc voltage source, when sputtering a target of Al, Si, Sn or In/Sn in an argon/oxygen atmosphere, is regulated with respect to voltage.

17. Apparatus as recited in claim 1, wherein the dc voltage source, when a target of Al or Si is sputtered in an argon/nitrogen atmosphere, is regulated with respect to voltage.