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AssigneeInternational Business Machines Corporation
InventorsThomas M. Cipolla, Paul W. Coteus, Glen W. Johnson, Philip Murphy, Christopher W. Oden
Estimating the term…
A method is described for aligning a contact pattern on an electronic device held by a first movable support, with a bond site pattern on a lead frame held by a second movable support. The method includes the steps of: (a) creating and storing models of a chip's contact pattern and a lead frame's bond site pattern; (b) imaging the electronic device and lead frame; (c) determining the position of contacts on said electronic device and reorienting the contact pattern model to a best fit with the imaged contact position; (d) determining the position of each bond site on the imaged lead frame and reorienting the bond site model to a best fit with the imaged bond site position; (e) determining positional differences between the reoriented lead frame and contact pattern models; and (f) generating signals to reorient the first and second movable supports to minimize the positional differences when they are moved into a bonding positon. A machine is described for performing the above method wherein each of three main movable elements of the machine is assigned a dimensional axis in which its travel is non-adjustable, so that other movable elements can be calibrated thereagainst.
A method for aligning a contact pattern on an electronic device held by a first movable support, with a bond site pattern on a lead frame held by a second movable support, comprising the steps of:
An apparatus for bonding contact areas of an electronic device to one of a plurality of lead frames, each said lead frame having a plurality of bond sites and first and second surfaces, said apparatus comprising;
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
Apparatus for manufacture or treatment: apparatus for mounting on conductive members, e.g. leadframes or conductors on insulating substrates
Characterised by the properties tested or measured, e.g. structural or electrical properties: structural properties, e.g. testing or measuring…
Conductor or circuit manufacturing: beam lead frame or beam lead device
Assembling to base an electrical component, e.g., capacitor, etc.: by utilizing optical sighting device
Term ended 6 Jul 2010 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
This invention relates to a method and apparatus for placing semiconductor devices on lead frames and, more particularly, to a method and system which enables fast and highly accurate chip placement and bonding on a TAB lead frame.
In tape automated bonding (TAB) microelectronic packaging, a set of beam leads (a "lead frame") electrically interconnects a semiconductor chip to a circuit-board substrate. The beam leads are supported on a polymer substrate called a TAB tape, and each frame of the TAB tape contains a new lead frame. Each lead frame contains an inner lead bond area where individual beam leads are aligned with a chip's contact location, and an outer lead bond area for electrically interconnecting the chip to a circuit board substrate. To make the desired interconnections between a chip and lead frame, a heated bonding head (thermode) forces the individual beam leads in the inner lead bond area against the chip's contacts to achieve a thermal, compression-bond.
TAB technology is moving in a direction of more leads and smaller spacings. Today, TAB lead sizes are on the order of two thousandth's of an inch widths on four thousandths centers. To assure proper registration, the semiconductor industry has been forced to use optical alignment techniques when placing chips on lead frames.
FIG. 1 is a partial perspective view of a chip placement and bonding machine which incorporates the invention.
FIG. 2 is a schematic perspective view of the major movable portion of the chip placement and bonding machine.
FIG. 3 is a high level block diagram showing the control system for the invention.
Referring now to FIG. 1, TAB tape 10 is fed from a feed reel 12 through a hitch feed mechanism 14 to a take up reel 15. The details of hitch feed mechanism 14 are described in copending U.S. patent application Ser. No. 07/546,496, entitled "Tape Automated Bonding Feeder" to Cipolla et al., filed on even date herewith.
In brief, hitch feed mechanism 14 comprises a movable gripper assembly 16 and a fixed jaw assembly 18. Movable gripper assembly 16 is mounted on a platform which is in turn mounted on a slider plate 20 that is connected to a bidirectional rotary motor 22 (shown partially). The action of motor 22 upon slider plate 20 causes it to move, reciprocally, along the directions indicated by arrows 24. Movable gripper assembly 16 is provided with a window 26 in which a leadframe on TAB tape 10 can be imaged and where a chip can be bonded.
During hitch feeding, motor 22 moves slider 20 to the left at the same time as grippers in movable gripper assembly 16 are opened. This action causes movable gripper assembly 16 to increment to the left by one lead frame. Simultaneously, fixed jaw assembly 12 is closed and prevents the movement of TAB tape 10, when movable gripper assembly 16 moves to the left. At the left-most limit of movement of slider plate 20, grippers in movable gripper assembly 16 close upon the edges of TAB tape 10, and the jaws in fixed jaw assembly 18 are opened. At this point, a new lead frame is positioned in window 26, and it is then incremented to the right by movement of slider plate 20 into the bonding position shown in FIG. 1.