Single chamber megasonic energy cleaner

• US 5,148,823 A
• Filed: 10/16/1990
• Issued: 09/22/1992
• Est. Priority Date: 10/16/1990
• Status: Expired due to Term

• Current Assignee: Akrion Incorporated
• Original Assignee: Verteg Incorporated
• Inventors: Bran, Mario E.
• Primary Examiner(s): Stinson, Frankie L.
• Application Number:
  US07/598,909
• Time in Patent Office: 707 Days
• Field of Search: 134/8, 134/902, 134/184, 134/186, 134/200, 134/76, 134/84, 134/91, 134/96, 134/98, 134/94, 134/95, 134/155, 18/355
• US Class Current: 134/184
• 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 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 21/67051 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

A cleaning system for semiconductor wafers wherein a megasonic energy cleaning system is utilized. Megasonic energy cleaning systems comprise a piezo-electric transducer and a transmitter. The transducer emits high frequency energy into the body of the transmitter. The transmitter radiates this energy into a container holding processing fluid. The energy causes the liquid to oscillate, thus vibrating contaminants off the surface of the wafer. The megasonic cleaning system is located atop a table which is mounted on a piston. In retracting the piston, the bottom of the container is removed any any liquid held within is dumped out into a second receptacle. The piston can then be returned to its extending position, and a rinsing agent can be added. Thus the megasonic cleaning system can be employed during the rinse cycle as well as the processing cycle, better cleaning the semiconductor wafer. The combination of the megasonic energy cleaning system with a dump valve provides for higher yield and superior purity in semiconductor processing. One version of the megasonic cleaning device is located in the lower part of a tank separate from the dump valve.

Claims

1. An apparatus for cleaning semi-conductor wafers and the like, comprising:

a tank for wafer-cleaning liquid and a wafer to be cleaned;

a dump valve in the lower portion of the tank for quickly dumping liquid from the tank, said dump valve including a movable valve member; and

a device for generating sonic energy positioned to agitate liquid in the tank to clean said wafer, said device being mounted to move with said member.

2. The apparatus of claim 1, wherein said member forms a substantial portion of the bottom wall of said tank.

3. The apparatus of claim 1, including an actuator supporting said member and said device to move the member with said device into open or closed positions with respect to said tank.

4. An apparatus for cleaning semi-conductor wafers and the like, comprising:

a tank for wafer-cleaning liquid and a wafer to be cleaned;

a dump valve in the lower portion of the tank for quickly dumping liquid from the tank; and

a device for generating megasonic energy positioned to agitate liquid in the tank to clean said wafer;

said tank having a bottom wall which forms a moveable valve member of said dump valve, and said device including a megasonic energy transducer vibrationally coupled to a megasonic energy transmitter which has a surface exposed to the interior of said tank;

said container being sized to receive a cassette carrying a plurality of wafers arranged in spaced parallel relation and with the wafers extending generally vertically with respect to the bottom wall above said transmitter, said cassette being positioned to straddle the dump valve and said device, said transmitter extending beneath the area in which said cassette is to be positioned, whereby megasonic energy is transmitted across both faces of each water positioned in the cassette.

5. The apparatus of claim 4, wherein said transmitter has a convex surface facing the interior of said tank to transmit said megasonic energy in a diverging pattern that subtends substantially the entire diameter of each of said wafers.

6. An apparatus for cleaning semi-conductor wafers and the like, comprising:

a tank for wafer-cleaning liquid and a wafer to be cleaned;

a dump valve in the lower portion of the tank for quickly dumping liquid from the tank; and

a device for generating megasonic energy positioned to agitate liquid in the tank to clean said wafer;

said device including a tube extending from one side of said tank to an opposite side of said tank with the tube being joined to said tank sides such that the tube defines a tubular space that is in open communication with the exterior of the tank, while the exterior of the tube is exposed to the liquid in the tank, said device including a transducer bonded to the interior of said tube to transmit energy through a wall portion of said tube into the liquid within the tube, said tube being located in the lower portion of said tank and the above said dump valve so that one or more wafers may be positioned above said tube to be cleaned by liquid agitated by said megasonic energy, and the liquid may be quickly dumped from the tank by way of said valve.