Systems and methods of monitoring thin film deposition

• US 6,668,618 B2
• Filed: 04/23/2001
• Issued: 12/30/2003
• Est. Priority Date: 04/23/2001
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Larson, John D. III, Ko, Herbert L., Karlquist, Richard K., Carey, Kent W., Hueschen, Mark A.
• Primary Examiner(s): CYGAN, MICHAEL T
• Application Number:
  US09/840,401
• Publication Number:
  US 20020152803A1
• Time in Patent Office: 981 Days
• Field of Search: 73/240.1, 73/240.3, 73/240.6, 73/616.2, 427/10, 427/8, 427/9, 340/870.16, 204/192.13, 204/298.03
• US Class Current: 73/24.01
• CPC Class Codes: C23C 14/546 using crystal oscillators
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: G01N 29/30 Arrangements for calibrating or comparing, e.g. with standard objects
• CPC Class Codes: G01N 29/4436 with a reference signal amplitude comparison G01N29/48

Abstract

Systems and methods of monitoring thin film deposition are described. In one aspect, a thin film deposition sensor includes an acoustical resonator (e.g., a thin film bulk acoustical resonator) that has an exposed surface and is responsive to thin film material deposits on the exposed surface. A substrate clip may be configured to attach the thin film deposition sensor to a substrate. A transceiver circuit may be configured to enable the thin film deposition sensor to be interrogated wirelessly. A method of monitoring a thin film deposition on a substrate also is described.

Claims

1. A system for monitoring a thin film deposition, comprising a thin film deposition sensor comprising a first thin film bulk acoustical resonator (FBAR) having an exposed surface and being responsive to thin film material deposits on the exposed surface and a second FBAR thermally coupled to the first acoustical resonator and shielded from deposition of thin film material, wherein the first FBAR and the second FBAR are formed on a common semiconductor substrate.

2. The system of claim 1, wherein the first and second acoustical resonators are coupled together by an electrical connection shielded from thin film material deposits.

3. The system of claim 1, further comprising an antenna configured to enable the thin film deposition sensor to be interrogated wirelessly.

4. The system of claim 1, wherein each of the first FBAR and the second FBAR has a thin film stack structure formed on a first surface of the semiconductor substrate and comprises a piezoelectric layer disposed between a pair of electrode layers, the first FBAR including an isolation cavity formed on a second surface of the semiconductor substrate opposite the first surface and a deposition shield disposed over the isolation cavity and having an exposed surface corresponding to the exposed surface of the first FBAR.

5. The system of claim 1, wherein each of the first FBAR and the second FBAR has a thin film stack structure formed on a first surface of the semiconductor substrate and comprises a piezoelectric layer disposed between a pair of electrode layers, the first FBAR including an isolation cavity extending through the semiconductor substrate to a second surface of the semiconductor substrate opposite the first surface, the thin film stack structure of second FBAR being disposed over an isolation cavity formed in the first surface of the semiconductor substrate.

6. A system for monitoring a thin film deposition, comprising a thin film deposition sensor comprising an acoustical resonator having an exposed surface and being responsive to thin film material deposits on the exposed surface, wherein the thin film deposition sensor further comprises a second acoustical resonator thermally coupled to the first acoustical resonator and shielded from deposition of thin film material, and the first and second acoustical resonators are coupled electrically in series.

7. The system 6, wherein the first and second acoustical resonators are thin film bulk acoustical resonators.

8. A system for monitoring a thin film deposition, comprising:

a thin film deposition sensor having an exposed surface exposed and being responsive to thin film material deposits on the exposed surface, wherein the deposition sensor comprises a thin film bulk acoustical resonator (FBAR) formed on a semiconductor substrate and having an exposed surface corresponding to the exposed surface of the deposition sensor; and

a transceiver circuit configured to enable the thin film deposition sensor to be interrogated wirelessly.

9. The system of claim 8, further comprising a first antenna coupled to the thin film deposition sensor and a second antenna coupled to the transceiver circuit.

10. The system of claim 9, wherein the second antenna is operable to transmit electromagnetic signals to the first antenna and to detect electromagnetic signals transmitted from the first antenna in response to excitation of the thin film deposition sensor by signals received from the second antenna.

11. The system of claim 8, wherein the transceiver circuit comprises an opto-electronic transducer.

12. The system of claim 8, wherein the thin film deposition sensor further comprises a second FBAR thermally coupled to the first FBAR and shielded from deposition of thin film material.

13. The system of claim 12, wherein the first FBAR and the second FBAR are coupled electrically in series.

14. The system of claim 12, wherein the first FBAR and the second FBAR are coupled together by an electrical connection shielded from thin film material deposits.

15. The system of claim 12, further comprising a plurality of pairs of exposed and shielded FBARS disposed on an elongated substrate.

16. The system of claim 15, wherein the FBARs of each pair are coupled electrically in series and the pairs of FBARs are inter-coupled electrically in parallel.

17. The system of claim 12, wherein each of the first FBAR and the second FBAR has a thin film stack structure formed on a first surface of the semiconductor substrate and comprises a piezoelectric layer disposed between a pair of electrode layers, the first FBAR including an isolation cavity formed on a second surface of the semiconductor substrate opposite the first surface and a deposition shield disposed over the isolation cavity and having an exposed surface corresponding to the exposed surface of the first FBAR.

18. The system of claim 12, wherein each of the first FBAR and the second FBAR has a thin film stack structure fanned on a first surface of the semiconductor substrate and comprises a piezoelectric layer disposed between a pair of electrode layers, the first FBAR including an isolation cavity extending through the semiconductor substrate to a second surface of the semiconductor substrate opposite the first surface, the thin film stack structure of second FBAR being disposed over an isolation cavity formed in the first surface of the semiconductor substrate.

19. The system of claim 12, wherein the optical transceiver circuit is mounted within a thin film deposition chamber.

20. The system of claim 8, wherein the transceiver circuit is an RFID tag circuit.

21. The system of claim 20, wherein the RFID circuit is electrically coupled to the thin film deposition sensor and comprises a power converter/transceiver, a modulator/demodulator circuit, a frequency discriminator, and a non-volatile memory.

22. A method of monitoring a thin film deposition on a substrate, comprising:

disposing within a deposition chamber a thin film deposition sensor comprising a first thin film bulk acoustical resonator (FBAR) having an exposed surface and being responsive to thin film material deposits on the exposed surface and a second FBAR thermally coupled to the first acoustical resonator and shielded from deposition of thin film material, wherein the first FBAR and the second FBAR are formed on a common semiconductor substrate; and

exposing a surface of the first acoustical resonator to a thin film deposition.

23. The method of claim 22, further comprising wirelessly interrogating the thin film deposition sensor to determine the resonant frequencies of the first FBAR and the second FRAR.

24. The method of claim 22, wherein wirelessly interrogating comprises transmitting an optical signal through an optical port of the deposition chamber.

25. The method of claim 22, wherein the thin film deposition sensor is disposed within the deposition chamber by attaching the thin film deposition sensor to a surface of the substrate, wherein the thin film deposition sensor is supported on the substrate surface.

26. A system for monitoring a thin film deposition, comprising a thin film deposition sensor comprising an acoustical resonator having an exposed surface and being responsive to thin film material deposits on the exposed surface, wherein the thin film deposition sensor further comprises a second acoustical resonator thermally coupled to the first acoustical resonator and shielded from deposition of thin film material, and further comprising a plurality of pairs of exposed and shielded acoustical resonators disposed on an elongated substrate, wherein the acoustical resonators of each pair are coupled electrically in series and the pairs of acoustical resonators are inter-coupled electrically in parallel.

27. A system for monitoring a thin film deposition, comprising a thin film deposition sensor comprising a thin film bulk acoustical resonator having an exposed surface and being responsive to thin film material deposits on the exposed surface, wherein the thin film deposition sensor further comprises a second thin film bulk acoustical resonator thermally coupled to the first thin film bulk acoustical resonator and shielded from deposition of thin film material, and further comprising a plurality of pairs of exposed and shielded thin film bulk acoustical resonators disposed on an elongated substrate.