Cleaning and liquid contact with solids – Processes – With work or work parts movable during treatment
Reexamination Certificate
1999-02-02
2001-05-22
Dang, Thi (Department: 1763)
Cleaning and liquid contact with solids
Processes
With work or work parts movable during treatment
C134S042000, C134S157000
Reexamination Certificate
active
06235126
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates generally to a cleaning systems for spherical-shaped objects, and more particularly, to a method and system for handling and cleaning very small spherical-shaped objects suitable for use in the manufacture of spherical-shaped semiconductor integrated circuits.
Conventional integrated circuits, or “chips,” are formed from a flat surface semiconductor wafer. The semiconductor wafer is first manufactured in a semiconductor material manufacturing facility and is then provided to a fabrication facility. At the latter facility, several layers are processed onto the semiconductor wafer surface. Once completed, the wafer is then cut into one or more chips and assembled into packages. Although the processed chip includes several layers fabricated thereon, the chip still remains relatively flat.
A fabrication facility is relatively expensive due to the enormous effort and expense required for creating flat silicon wafers and chips. For example, manufacturing the wafers requires several steps including making rod-form high purity polycrystalline semiconductor material, manufacturing a large single crystalline ingot from melted high purity polycrystalline semiconductor material in a quartz crucible, cutting the ingot into pieces (wafers), and lapping, polishing and cleaning wafers. Device fabrication processes thereafter include several high-temperature processes such as oxidation, doping, and diffusion, as well as chemical processes such as wet etching, chemical vapor deposition (“CVD”), chemical mechanical polishing (“CMP”), and photolithography process.
Another major problem associated with modern fabrication facilities for flat chips is that they require extensive and expensive equipment. For example, dust-free clean rooms and temperature-controlled manufacturing and storage areas are necessary to prevent the wafers and chips from defecting and warping. Also, these types of fabrication facilities suffer from a relatively inefficient throughput as well as an inefficient use of the silicon. For example, because the wafers are round and the completed chips are rectangular, the peripheral portion of each wafer cannot be used.
Therefore, due to these and various other problems, only a few companies in the world today can successfully manufacture conventional flat chips. Furthermore, the chips must bear a high price to cover the costs of manufacturing, as well as the return on initial capital and investment.
In co-pending U.S. Pat. No, 5,955,776 filed on May 16, 1997, assigned to the same assignee as the present application and hereby incorporated by reference as if reproduced in its entirety, a method and system for manufacturing spherical-shaped semiconductor integrated circuits is disclosed. As disclosed in the aforementioned patent application, the manufacturing process by which a spherical-shaped semiconductor integrated circuit device is produced may include a variety of processing steps.
Complicating the manufacturing process for spherical-shaped semiconductor integrated circuit devices are the special handling requirements which must be afforded the devices during their manufacture. Unlike conventional integrated circuits formed on flat surface semiconductor wafers, the integrated circuit may consume the entire surface area of the spherical-shaped semiconductor device. Also, unlike conventional integrated circuits which may be grasped along bottom or side surfaces thereof, grasping or otherwise contacting spherical-shaped semiconductor integrated circuit devices during the manufacturing process may result in significant damage. Furthermore, many of the processing techniques used to manufacture conventional integrated circuits are unsuitable for use in the manufacture of spherical-shaped semiconductor integrated circuit devices.
In particular, cleaning a spherical-shaped semiconductor substrate or integrated circuit device can not be performed in the same way as cleaning a relatively flat semiconductor wafer. Unlike conventional semiconductor wafers that can be placed in a container and sprayed or immersed with cleaning agent, the spherical-shaped semiconductor integrated circuit devices must be cleaned on all surfaces, with special care in the touching and handling of the surfaces. Also, unlike devices for cleaning other spherical shaped devices such as ball bearings, spherical-shaped semiconductor integrated circuits are extremely small, typically about 1 millimeter (mm) in diameter, and can be damaged very easily. The cleaning devices for ball bearings cannot be simply scaled down to this degree. Also, the spherical-shape semiconductor integrated circuits are extremely susceptible to scratches and other type of surface damage.
Therefore, the difficulties associated with the handling and cleaning of spherical-shaped semiconductor devices during the manufacturing process remains an obstacle to the development of such devices. Thus, there remains a need for a system and method capable of cleaning very small spherical-shaped semiconductor devices without damaging their outer surface.
SUMMARY OF THE INVENTION
In one embodiment, the present invention provides a system and method for cleaning very small spherical shaped semiconductor devices. The system includes an enclosure for housing a pair of rollers. The enclosure also includes a fluid inlet for receiving a cleaning agent and a product inlet for receiving the spherical shaped semiconductor device. A motor rotates one or both of the rollers.
In operation, the spherical shaped semiconductor device and the cleaning agent are provided into the enclosure. The device passes to the pair of rollers and is cleaned by the cleaning agent and the rotating rollers. Once cleaned, the spherical shaped device and cleaning agent pass into a separator and the device is fully cleaned.
In another embodiment, the system can sequentially clean a plurality of spherical shaped semiconductor devices. The system includes an enclosure for housing two pairs of rollers. The enclosure also includes the fluid inlet for receiving the cleaning agent and the product inlet for receiving the sequence of spherical shaped semiconductor devices. A motor rotates one or both of the rollers of each pair so that in a first direction of rotation, the rollers cause a spherical shaped semiconductor device to pass through the pair of rollers, and in the opposite direction the device stays inside or above the pair of rollers.
In operation, a first spherical shaped semiconductor device is provided to the first pair of rollers. The first pair of rollers are rotating so that the first spherical shaped semiconductor device stays in the first pair of rollers. The first pair of rollers then rotates in the opposite direction so that the first spherical shaped semiconductor device passes to the second pair of rollers.
In some embodiments, after the first spherical shaped semiconductor device is passed to the second pair of rollers, the first pair of rollers changes rotational direction again. In this way, the first pair of rollers can receive and keep another spherical shaped semiconductor device.
As a result, the system provides an efficient means for handling and cleaning spherical-shaped semiconductor devices during the manufacturing process. The system is capable of cleaning very small spherical-shaped devices without damaging their outer surface and is operable to support a “pipeline” production process.
REFERENCES:
patent: 4899413 (1990-02-01), Trobiani
patent: 4958396 (1990-09-01), Butler et al.
patent: 4974763 (1990-12-01), Widrig
patent: 4984629 (1991-01-01), Voith et al.
patent: 5004239 (1991-04-01), Wettstein
patent: 5010950 (1991-04-01), Voith
patent: 5056946 (1991-10-01), Larkin
patent: 5361440 (1994-11-01), Buchbinder et al.
patent: 5462639 (1995-10-01), Matthews et al.
patent: 5519910 (1996-05-01), Messina
patent: 5546629 (1996-08-01), Shim
patent: 5669096 (1997-09-01), Worsham
patent: 5673918 (1997-10-01), Bigari
patent: 5680665 (1997-10-01), Anson et al.
patent: 2-119241 (1988-10-01), None
Ball Semiconductor Inc.
Dang Thi
Haynes and Boone LLP
LandOfFree
Cleaning system for very small semiconductor... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cleaning system for very small semiconductor..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cleaning system for very small semiconductor... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2438067