One-piece cleaning tank with indium bonded megasonic transducer

• US 20020050768A1
• Filed: 04/23/2001
• Published: 05/02/2002
• Est. Priority Date: 08/27/1999
• Status: Active Grant

• Current Assignee: Product Systems Incorporated
• Original Assignee: Product Systems Incorporated
• Inventors: Beck, Mark J., Vennerbeck, Richard B.
• Granted Patent: US 6,722,379 B2
• Time in Patent Office: Days
• US Class Current: 310/334
• CPC Class Codes: B06B 1/0618 of piezo- and non-piezoelectric elements, e.g. 'Tonpilz'
• CPC Class Codes: B06B 3/02 involving a change of amplitude
• CPC Class Codes: B08B 17/02 Preventing deposition of fouling or of dust
• CPC Class Codes: B08B 3/12 by sonic or ultrasonic vibrations washing or rinsing machines for crockery or tableware using sonic or ultrasonic waves A47L15/13; of natural teeth, of prostheses using ultrasonic techniques similar to those used for natural teeth A61C17/20; application of ultrasonic vibrations to chemical, physical or physico-chemical processes in general B01J19/10
• CPC Class Codes: G10K 11/02 Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators
• CPC Class Codes: G10K 11/025 horns for impedance matching see provisionally also G10K11/28
• CPC Class Codes: H01L 21/67057 with the semiconductor substrates being dipped in baths or vessels
• CPC Class Codes: Y10S 134/902 Semiconductor wafer

Abstract

A megasonic cleaning system comprised of a one-piece cleaning tank, one or more piezoelectric crystals and an indium layer for attaching the piezoelectric crystals to the cleaning tank. The tank comprises a material selected from the group consisting of quartz, sapphire, silicon carbide, silicon nitride, ceramics and stainless steel. The piezoelectric crystals are attached directly to a side or to the bottom of the tank.

Claims

1. A megasonic cleaning system comprising:

a tank for holding a volume of cleaning solution, the tank comprising a plurality of sides and a bottom;

at least one piezoelectric crystal for generating acoustic energy in the frequency range of 0.4 to 2.0 MHz when power is applied to the piezoelectric crystal; and

a bonding layer comprised of indium positioned between the piezoelectric crystal and the bottom or one of the sides for attaching the piezoelectric crystal to the tank.

2. The megasonic cleaning system of claim 1 wherein the bonding layer comprises at least 99.99% indium.

3. The megasonic cleaning system of claim 1 wherein the tank comprises a material selected from the group consisting of quartz, sapphire, silicon carbide, silicon nitride, ceramics and stainless steel.

4. The megasonic cleaning system of claim 3 wherein the tank comprises a single continuous piece of the material.

5. The megasonic cleaning system of claim 1 further comprising a combination layer positioned between the bonding layer and the quartz tank, the combination layer functioning at least as a wetting layer to facilitate attachment of the bonding layer to the tank.

6. The megasonic cleaning system of claim 5 wherein the combination layer comprises a silver emulsion that is applied to the tank using a screen process.

7. A megasonic cleaning system comprising:

a quartz tank for holding a volume of cleaning solution, the tank comprising a plurality of sides and a bottom;

at least one piezoelectric crystal for generating acoustic energy in the frequency range of 0.4 to 2.0 MNz when power is applied to the piezoelectric crystal; and

a bonding layer comprised of indium positioned between the piezoelectric crystal and the bottom or one of the sides for attaching the piezoelectric crystal to the quartz tank.

8. The megasonic cleaning system of claim 7 further comprising a combination layer positioned between the bonding layer and the quartz tank, the combination layer functioning at least as a wetting layer to facilitate attachment of the bonding layer to the quartz tank.

9. The megasonic cleaning system of claim 8 wherein the combination layer comprises a silver emulsion that is applied to the quartz tank using a screen process.

10. The megasonic cleaning system of claim 7 wherein the quartz tank comprises a single continuous piece of quartz.

11. The megasonic cleaning system of claim 10 wherein the sides of the quartz tank each have a length of approximately thirty centimeters or greater.

13. The megasonic transducer of claim 12 wherein the bonding layer comprises at least 99.99% indium.

14. The megasonic transducer of claim 12 wherein the piezoelectric crystal comprises lead zirconate titanate.

16. The megasonic cleaning system of claim 15 wherein the bonding layer comprises at least 99.99% indium.

17. The megasonic cleaning system of claim 15 wherein the tank comprises a material selected from the group consisting of quartz, sapphire, silicon carbide, silicon nitride, ceramics and stainless steel.

18. The megasonic cleaning system of claim 17 wherein the tank comprises a single continuous piece of the material.

19. The megasonic cleaning system of claim 15 wherein the first adhesion layer comprises chromium.

20. The megasonic cleaning system of claim 15 wherein the first wetting layer comprises silver.

21. The megasonic cleaning system of claim 15 further comprising:

a second adhesion layer positioned in contact with a surface of the tank; and

a second wetting layer positioned between the second adhesion layer and the bonding layer for helping the bonding layer bond to the second adhesion layer.

22. The megasonic cleaning system of claim 21 wherein the second adhesion layer comprises chromium.

23. The megasonic cleaning system of claim 21 wherein the second wetting layer comprises silver.

12. A megasonic transducer comprising:

a piezoelectric crystal for generating acoustic energy in the frequency range of 0.4 to 2.0 MHz;

an resonator comprised of quartz and adapted for positioning between the piezoelectric crystal and a volume of cleaning fluid; and

a bonding layer comprised of indium positioned between the resonator and the piezoelectric crystal for attaching the piezoelectric crystal to the resonator.

15. A megasonic cleaning system comprising:

a tank for holding a volume of cleaning solution, the tank comprising a plurality of sides and a bottom;

at least one piezoelectric crystal for generating acoustic energy in the frequency range of 0.4 to 2.0 MHz when power is applied to the piezoelectric crystal; and

a bonding layer comprised of indium positioned between the piezoelectric crystal and the bottom or one of the sides for attaching the piezoelectric crystal to the tank;

a first adhesion layer positioned in contact with a surface of the piezoelectric crystal; and

a first wetting layer positioned between the first adhesion layer and the bonding layer for helping the bonding layer bond to the first adhesion layer.