Inventor’s Corner

Wireless particle counter
The method and apparatus counts and measures contamination in air, gas and liquids. It includes a remote sensor (A), a wireless data processing and control system (B), a microprocessor (C) and a wireless communication means (D).

The wireless unit has a transmitter-receiver (E) that is connected to antenna (F). The sensor system (A) includes a particle detection system (G) that senses refraction created by the intersection of particles with a light beam within the particle detection system (G).

Click here to enlarge image

The particle detection system processes the detected signals, and the wireless communication means (A) sends information to the data processing and control system (B), where results can be viewed on the display (H).

Patent number: 6,346,983
Date granted: February 12, 2002
Inventor: Aleksandr L. Yufa, of Colton, CA

Purification system
The unit has a filter (A) made of laminated fiber sheets (B) and contained within a box (C). A non-woven fabric (D) and aluminum screen (E) is placed over the sheets, and the entire unit is then secured with a cover (F).

Click here to enlarge image

Openings on either side of the unit (G,H) allow gas to flow through the fiber sheets and be cleaned, decreasing chemical pollutants in a gas, particularly in the air supplied to a cleanroom, booth or bench, to very low levels. The unit uses ion exchange or electric charge adsorbing action for less pressure loss for the gas being treated.

Patent number: 6,352,579 B1
Date granted: March 5, 2002
Inventors: Nami Hirata, Yoichi Fujumura; Hideo Saruyama, and Masaki Amano, of Toray Industries Inc. (Shiga and Chiba, Japan)

Wafer dry-cleaning method
Disclosed in the invention is a method for dry cleaning a wafer containers (A) such as a SMIF pod, that are equipped with a bottom mounting plate (B) that is covered with contaminating particles (C).

In the method, the wafer containers are mounted in openings of the enclosure (D) so that bottom mounting plates with the contaminating particles are exposed to an air-tight cavity (E) of the enclosure.

Click here to enlarge image

A purge gas flow is then directed to the bottom of the mounting plates to dislodge the contaminating particles which are then picked up by a vacuum conduit (F) positioned juxtaposed to the purge gas conduit (G) and connected to a factory vacuum source (H) to remove particles.

The method can be used without using wet bench cleaning, and, according to the inventors, achieve desirable and efficient cleaning results.

Patent number: 6,358,328 B1
Date granted: March 19, 2002
Inventors: Huai-Tei Yang, Suan-Jun Kuan, Ching-Ling Lee, Kuo-Hung Liao, of Taiwan Semiconductor Manufacturing Co. Ltd (Hsin-Chu, Taiwan).

Contamination reduction
The invention is a method for depositing a film on a surface of a semiconductor wafer, while preventing defects on the surface.

The method calls for selecting a quartz carrier for holding the wafer during film deposition, and must be one that has quartz rods with fire-polished slots for receiving the wafer's edge.

Click here to enlarge image

The wafer is then placed into the quartz carrier with its edge within the fire-polished slots, and the carrier and wafer are loaded into a deposition chamber. Air is evacuated from the deposition chamber, and the temperature is raised and the pressure is adjusted to conducive levels. Process gases are then introduced to the deposition chamber, and by reaction of the gases, the film is deposited on the surface of the wafer and on the wafer carrier.

Using a wafer carrier having fire-polished slots provides better adhesion of the deposited film to the wafer carrier. The increased adhesion prevents spalling of the film off of the wafer carrier, which causes particles of the film to damage the wafer. Such contamination introduces defects to the wafer, which would render the wafer useless.

Patent number: 6,355,577 B1
Date granted: March 12, 2002
Inventors: Steven E. Reder and Ynhi T. Lee, of LSI Logice Corp. (Milpitas, CA)

Send your inventions
Information on the patents highlighted above was obtained through the U.S. Patent and Trademark Office. Inventors who have been granted patents within the last six months for new cleanroom and contamination technology are encouraged to submit them to CleanRooms magazine for publication. Send a brief description of the invention along with a detailed drawing to Mark A. DeSorbo, associate editor, CleanRooms, 98 Spit Brook Road, Nashua, NH 03062, or e-mail at [email protected].


Easily post a comment below using your Linkedin, Twitter, Google or Facebook account. Comments won't automatically be posted to your social media accounts unless you select to share.