Method for producing piezoelectric films with rotating magnetron sputtering system

• US 6,342,134 B1
• Filed: 02/11/2000
• Issued: 01/29/2002
• Est. Priority Date: 02/11/2000
• Status: Expired due to Term

• Current Assignee: Bell Semiconductor, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: Agere Systems Guardian Corp. (Broadcom, Inc.)
• Inventors: Miller, Ronald Eugene, Barber, Bradley Paul
• Primary Examiner(s): Nguyen, Nam
• Assistant Examiner(s): VerSteeg, Steven H.
• Application Number:
  US09/503,225
• Time in Patent Office: 718 Days
• Field of Search: 204/192.12, 204/192.13, 204/192.18, 204/192.22, 204/192.3, 427/8, 216/38, 29/253.5
• US Class Current: 204/192.18
• CPC Class Codes: C23C 14/0094 in transition mode
• CPC Class Codes: C23C 14/0617 AIII BV compounds, where A is Al, Ga, In or Tl and B is N, P, As, Sb or Bi
• CPC Class Codes: C23C 14/35 by application of a magnetic field, e.g. magnetron sputtering C23C14/3457 takes precedence
• CPC Class Codes: H10N 30/076 by vapour phase deposition
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

A quality-assurance method is described that is useful in the fabrication of piezoelectric films of electronic devices, particularly resonators for use in RF filters. For example, the method comprises determining the surface roughness of an insulating layer on which the piezoelectric film is to be deposited and achieving a surface roughness for the insulating layer that is sufficiently low to achieve the high-quality piezoelectric film. According to one aspect of the invention, the low surface roughness for the insulating layer is achieved with use of a rotating magnet magnetron system for improving the uniformity of the deposited layer. According to other aspects of the invention, the high-quality piezoelectric film is assured by optimizing deposition parameters including determination of a “cross-over point” for reactive gas flow and/or monitoring and correcting for the surface roughness of the insulating layer pre-fabrication of the piezoelectric film.

Claims

1. A method for use in fabricating a piezoelectric film deposited on at least one insulating layer having a thickness characterized by a thickness uniformity and a surface characterized by a surface roughness comprising determining the surface roughness of the at least one insulating layer and, before the piezoelectric film is deposited, achieving a surface roughness for the insulating layer of less than 10 Å

(RMS).

2. The method of claim 1 in which at least one metal layer is deposited between the insulating layer and the piezoelectric film.

3. The method of claim 1 comprising a reactive sputtering process using rotating magnet magnetrons and pulsed DC power in depositing the at least one insulating layer for promoting the thickness uniformity of the at least one insulating layer.

4. The method of claim 1 comprising a reactive sputtering process using rotating magnet magnetrons and pulsed DC power in depositing the piezoelectric film for promoting the thickness uniformity of the piezoelectric film.

5. The method of claim 1 comprising a reactive sputtering process in which a target material and a substrate are disposed within a sputtering chamber and a reactive gas is introduced into the chamber, the sputtering process including a flow of reactive gas into the sputtering chamber, the flow characterized by a cross-over point, wherein the process further comprises the steps of:

determining the cross-over point for the flow of a reactive gas into the sputtering chamber; and

introducing a reactive gas into the sputtering chamber, wherein the reactive gas reacts with a portion of said target material, the reactive gas being introduced into the sputtering chamber at a flow rate corresponding substantially to the flow rate at the cross-over point.

6. The method of claim 1 in which the surface roughness of the at least one insulating layer is non-destructively measured in situ by an acoustic force microscope.

7. The method of claim 1 in which the desired surface roughness is achieved with use of chemical mechanical polishing or a hydrogen hot sputter etch process.