News Column

Patent Issued for Substrate Alignment System

June 18, 2014



By a News Reporter-Staff News Editor at Journal of Engineering -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventors Kaveh, Farro (Palo Alto, CA); Aalund, Martin P. (Sunnyvale, CA), filed on May 11, 2006, was published online on June 3, 2014.

The assignee for this patent, patent number 8744624, is KLA-Tencor Corporation (Milpitas, CA).

Reporters obtained the following quote from the background information supplied by the inventors: "Modern integrated circuits are customarily fabricated on substantially round slices of a semiconductor or other material, commonly called substrates or wafers. As the term is used herein, 'integrated circuit' includes devices such as those formed on monolithic semiconducting substrates, such as those formed of group IV materials like silicon or germanium, or group III-V compounds like gallium arsenide, or mixtures of such materials. The term includes all types of devices formed, such as memory and logic, and all designs of such devices, such as MOS and bipolar. The term also comprehends applications such as flat panel displays, solar cells, and charge coupled devices.

"In many instances during the fabrication process it is desired to place the substrate within a piece of processing equipment or a piece of inspection equipment (jointly and severally referred to as 'tools' herein) in a desired position. As the term is used herein, 'position' refers to two components. The first component is offset, or in other words the x,y,z location of the substrate within the plane defined by the substrate. The second component is orientation, or in other words the disposition of the substrate with respect to rotation within the plane, or the pitch and yaw of the plane as determined by a reference. It is understood that the term 'position' could also refer to other components of location of an object within a three-dimensional space, but the two components described above are of primary importance in the discussion presented herein.

"Currently, a variety of methods are used to place a substrate in a desire position. Formerly, the substrate would be placed on a rotating chuck and the edge of the substrate would be rotated against a physical element, such as a pin, that senses a notch or flat in the circumferential edge of the substrate as it rotates past the physical element. The substrate is then placed in a position with respect to the notch. More recently, the substrate is rotated at a relatively high rate of speed with the circumferential edge of the substrate disposed under a linear CCD element that finds the notch. The rotation again a physical element or the high rate of rotation requires that the substrate be retained to the chuck, such as by being gripped at the edge or by a vacuum chuck, but not by gravity alone.

"Unfortunately, adding such pre-aligner systems to all the tools that might benefit from their use can be quite expensive, in a variety of different ways. Current pre-aligner systems have a relatively high cost of more than about six thousand dollars each, are prone to failure, and take up valuable space. What is needed, therefore, is a system that overcomes problems such as those described above, at least in part."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "The above and other needs are met by a substrate loading system, having a vision system adapted to view a substrate and provide position signals indicative of substrate position. A controller receives the position signals from the vision system, determines the substrate position, and sends transport signals to a robot arm. The robot arm engages the substrate in a beginning location and a beginning position and transports the substrate to a desired location and a desired position, based at least in part on the transport signals received from the controller.

"In this manner an expensive pre-alignment system is not required. Instead, a robot arm and a vision system can be used to transport and position the substrate. Many loading mechanisms already have robot arms, and thus only a vision system needs to be added, with appropriate programming and control of the robot arm, to adapt the equipment to this new system. Thus, implementation of the present system can be very cost effective.

"In various embodiments, the beginning location of the substrate is a cassette and the desired location of the substrate is within a tool. Preferably, the beginning position and the desired position have common pitch and yaw components. In some embodiments, a fiducial is commonly viewed with the substrate by the vision system to provide referenced position signals. The fiducial may be disposed on the robot arm or on an element other than the robot arm and the vision system, which other element is in a known location and position relative to the vision system. The robot arm preferably retains the substrate with gravity alone. Some embodiments use an intermediate stage on which the robot arm places the substrate, releases the substrate, and re-engages the substrate from a different orientation, in order to position the substrate in the desired location in the desire position. In various embodiments, the means that is used to determine the substrate position is at least one of a flat on the substrate, a notch on the substrate, and circuit elements on the substrate.

"According to another aspect of the invention there is described a method of transporting a substrate from a beginning location and a beginning position to a desired location and a desired position, by: (a) viewing a substrate with a vision system, (b) providing position signals indicative of substrate position, receiving the position signals from the vision system with a controller, (d) determining the substrate position with the controller, (e) sending transport signals to a robot arm from the controller, (f) engaging the substrate with the robot arm in the beginning location and the beginning position, and (g) transporting the substrate with the robot arm to the desired location and the desired position, based at least in part on the transport signals received from the controller. In various embodiments, the steps of the method are performed in the listed order. Alternately, step (f) is performed prior to the other steps as listed."

For more information, see this patent: Kaveh, Farro; Aalund, Martin P.. Substrate Alignment System. U.S. Patent Number 8744624, filed May 11, 2006, and published online on June 3, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8744624.PN.&OS=PN/8744624RS=PN/8744624

Keywords for this news article include: KLA-Tencor Corporation.

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Source: Journal of Engineering


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