Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
1997-06-18
2002-05-21
Vo, Peter (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S740000, C029S720000
Reexamination Certificate
active
06389688
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is generally directed to a method and apparatus for bringing a component into register with a support with a high degree of precision. More particularly this invention relates to the precise alignment of an electronic chip on a supporting structure.
2. Description of Related Art
Considerable effort has been directed to developing methods and apparatus for precisely positioning one component, such as an electronic chip, on a second component, such as a supporting structure or substrate of any of diverse forms. In accordance with one prior art approach, a robotic device includes a video system to bring bonding pads on a semiconductor device, as the one component or piece, into registration with leads on a substrate as a supporting structure as a second component or piece. Basically, the video system images features on each of the component and supporting structure when they are at locations remote from a work station at which they will actually be joined. If a control system “knows” the position of the robotic device when each video image is produced and the position of each feature on the component with respect to the position of the supporting structure, calculations can then be made to determine a vector over which one of the components must traverse relative to the other component to be in register. After the traversal is complete, the robotic device brings the two pieces into contact, generally by displacing the semiconductor device to the substrate. In addition to robotic systems manufactured by the assignee of this invention, there are a number of variations on this method and apparatus that are exemplified in the following patents:
U.S. Pat. No. 3,923,584 to Hojo et al. (1975) discloses one such positioning arrangement for providing a face down bonder. The surfaces of the two components to be mated together in registration are established as opposed surfaces; the component positions are adjustable horizontally and vertically. A compound prism comprises a truncated quadrangular right prism with a 45° truncation and a rectangular prism that form a parallelopiped with a half-silvered mirror film at a common interface and with a total reflecting mirror film at a vertical surface of the rectangular prism. When the two components are spaced apart, the prism is interposed between them to allow images to be taken of the two components. Once the images are taken, the optical mechanism is removed, so the two components can be brought together.
U.S. Pat. No. 4,404,741 (1983) to Lebet et al. discloses an alignment device that includes a gripping device for carrying a part over a substrate. An optical device in the form of a microscope or television camera apparently monitors external housing features in order to assure proper alignment.
U.S. Pat. No. 4,526,646 (1983) to Suzuki et al. discloses an inner lead bonder in which a die is fed along a path. It first is positioned at a die defect camera that enables the removal of defective dies. Next a die positional pattern detecting camera images the die at one location. A lead positional pattern detecting camera monitors the positional pattern of leads on a carrier tape. Once these images have been processed, appropriate alignment is made based upon the information in the images produced by the later two cameras.
U.S. Pat. No. 4,657,170 (1987) to Müller discloses a process for bonding an electric component to a connecting tag block in a machine and tape for carrying out the process. An optical instrument
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is located above a supporting table at which assembly occurs. This enables an operator to see the tape as well as one integrated circuit positioned on the table to determine whether the integrated circuit is properly aligned with the tape. Adjustment of the position is then allowed.
U.S. Pat. No. 4,671,446 (1987) to Sherman discloses a method and system for automatically bonding a lead wire on a semiconductor. In accordance with this method, a contact carrying surface is illuminated at the Brewster's angle with a beam of light rays having a wavelength in the range of the light transmission coefficient of the semiconductor material constituting the chip. Either the illuminating beam or the reflected beam or both are polarized to produce a difference in intensity of the light reflected from the contact and the light reflected from the semiconductor area. The illuminating light passes through a filter to render to a narrow frequency beam of light rays. The result is enhanced contrast in the reflected beam that is more readily digitized for providing inputs to positioning equipment.
U.S. Pat. No. 4,899,921 (1990) to Bendat et al. discloses alignment apparatus in which an optical probe is intermediate a chip and a substrate. The probe illuminates both the counterfacing surfaces of both the chip and substrate and combines the two images into a single image. After the alignment is correct, the probe is withdrawn to allow the chip to be mounted on the substrate.
U.S. Pat. No. 4,980,971 (1991) to Bartschat et al. discloses a system for precisely placing a semiconductor chip on a substrate. A robotic arm with a gripper separately picks up the chip and the substrate. A first television camera, carried by the robotic arm, captures the image of the substrate to locate a pair of datum points. A second camera, that is stationary with respect to the robotic arm, captures the image of the chip when engaged by the robot to locate another pair of datum points. A machine vision system processes the output signals of both cameras to establish the precise location of the datum points on each of the substrate and chip. This controls the robotic arm to cause the gripper to place the chip on the substrate at a precise location.
U.S. Pat. No. 5,195,234 (1993) to Pine et al. discloses a method and apparatus for visual alignment of parts that includes a device, such as a robotic arm, for picking and placing a part on an object. One device moves and removes optics into and out of a work envelope that contains the object. Another device utilizes information from the optics device for locating landmarks on the object within the work envelope thereby to allow alignment of the part with the landmark in the work envelope. After the optics are removed, the two components are displaced relative to each and into contact.
U.S. Pat. No. 5,523,586 (1996) to Sakurai discloses a burn-in socket used in a burn-in test for semiconductor chips that includes a transparent cover member. The cover member is constituted by fixing an inexpensive TAB tape, which can be finally processed, to a transparent member of glass or other transparent material. The chip electrodes of a semiconductor chip to be tested are set in the recess of the chip container and electrically connect to internal electrodes of the chip container by use of leads on the TAB tape. The alignment of the leads, chip electrodes and internal electrodes is facilitated by viewing through the TAB tape from the cover member by video or other means.
U.S. Pat. No. 5,590,456 (1997) to Armington et al. discloses an apparatus for precisely aligning and placing optoelectric components on a substrate. A single camera looks through a transparent alignment tool that holds the component to the substrate below it thus allowing both the component and the substrate to be seen together by the camera. The alignment tool and substrate are adjusted to align the two precisely and then are brought together while being seen by the camera. If the optoelectric component is a laser chip, the chip can be energized while on the glass alignment tool to produce a laser spot that is superimposed on the visible light image via a series of lenses and mirrors.
There now exists a new class of electronic chip-substrate combinations called chip scale packages. The counterfacing surfaces of the chip and substrate carry bonding pads and terminals respectively. The bonding pads are typically about 4 mils square; the leads have a cross section of about 2 mils. In order to assure appropr
Devasia Cyriac
Srivastava Nilendu
Sun Sung Ping
Herbster George A.
Micro Robotics Systems Inc.
Smith Sean
Vo Peter
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