Wafer cleaning

• US 20040206371A1
• Filed: 12/03/2003
• Published: 10/21/2004
• Est. Priority Date: 09/30/1996
• Status: Active Grant

• Current Assignee: Akrion Incorporated
• Original Assignee: Akrion Technologies Incorporated (Akrion Incorporated)
• Inventors: Bran, Mario E.
• Granted Patent: US 7,117,876 B2
• Time in Patent Office: Days
• US Class Current: 134/1.3
• CPC Class Codes: B06B 3/00 Methods or apparatus specially adapted for transmitting mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
• 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: H01L 21/02041 Cleaning
• CPC Class Codes: H01L 21/67051 using mainly spraying means, e.g. nozzles
• 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

Semiconductor wafers are cleaned using megasonic energy to agitate cleaning fluid applied to the wafer. A source of energy vibrates an elongated probe which transmits the acoustic energy into the fluid. The probe has a solid cleaning rod and a flared or stepped rear base. In one form, the probe is made of one piece, and in another, the rod fits into a socket in the base. This enables a rod to be made of material which is compatible with the cleaning solution, while the base may be of a different material. A heat transfer member acoustically coupled to the probe base and to a transducer conducts heat away from the transducer. A housing for the heat transfer member and the transducer supports those components and provides means for conducting coolant through the housing to control the temperature of the transducer. In another arrangement, an end of the housing is coupled between the transducer and the probe. In one arrangement, fluid is sprayed onto both sides of a wafer while a probe is positioned close to an upper side. In another arrangement, a short probe is positioned with its end face close to the surface of a wafer, and the probe is moved over the wafer as it rotates. The probe may also be positioned through a central hole in a plurality of discs to clean a group of such elements at one time.

Claims

1. A method of processing a thin, flat substrate, comprising:

supporting the substrate in a generally horizontal orientation; and

transmitting sonic energy to the substrate while flowing liquid onto both sides of the substrate to loosen particles on both sides of the substrate while maintaining said orientation.

2. The method of claim 1, including positioning a transmitter adjacent to one side of the substrate to transmit said energy through the liquid to the substrate.

3. The method of claim 2 wherein said one side is the upper side of the substrate.

4. The method of claim 1, wherein said energy is megasonic energy.

5. A method of cleaning thin articles having two generally planar opposite sides, said method comprising:

applying cleaning fluid to one of said sides while supporting said article in a generally horizontal orientation; and

applying energy to the other one of said sides with sufficient power to produce vibration on said one side in the area of said cleaning fluid to loosen particles on said one side, while maintaining said orientation.

6. The method of claim 5, wherein said energy is applied by applying cleaning fluid to said other side of the article to couple said vibration to the article so as to loosen particles on both sides of the article at the same time.

7. The method of claim 6, wherein said energy is applied by an energy transmitter closely spaced from said other side.

8. The method of claim 7 wherein said other side is the upper side of the article.

9. The method of claim 5, wherein said vibration is at one or more megasonic frequencies.

10. The method of claim 5 wherein said energy is applied by an energy transmitter closely spaced from said other side.

11. The method of claim 10 wherein said other side is the upper side of the article.