Apparatus and method for inspection and alignment of semiconductor chips and conductive lead frames
First Claim
1. 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:
- a. creating and storing precise models of contact and bond site patterns;
b. deriving images of said electronic device contact pattern and said lead frame, said electronic device and lead frame to be hereafter moved by said first and second movable supports into a bonding position to enable said electronic device contact pattern to be bonded to bond sites on said lead frame;
c. determining the position of contacts in said imaged contact pattern, and reorienting said contact pattern model to a best fit with said determined contact positions;
d. determining the position of bond sites on said imaged lead frame, and reorienting said bond site model to a best fit with said determined bond site positions;
e. finding positional differences between said reoriented bond site and contact pattern models; and
f. generating signals to reorient said first and second movable supports to minimize said positional differences when said first and second supports are moved into said bonding position.
1 Assignment
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Accused Products
Abstract
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.
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Citations
22 Claims
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1. 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:
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a. creating and storing precise models of contact and bond site patterns; b. deriving images of said electronic device contact pattern and said lead frame, said electronic device and lead frame to be hereafter moved by said first and second movable supports into a bonding position to enable said electronic device contact pattern to be bonded to bond sites on said lead frame; c. determining the position of contacts in said imaged contact pattern, and reorienting said contact pattern model to a best fit with said determined contact positions; d. determining the position of bond sites on said imaged lead frame, and reorienting said bond site model to a best fit with said determined bond site positions; e. finding positional differences between said reoriented bond site and contact pattern models; and f. generating signals to reorient said first and second movable supports to minimize said positional differences when said first and second supports are moved into said bonding position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. 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;
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advancing means for moving a lead frame into a bonding position, said advancing means being adjustably movable along a first axis but fixed along a second orthogonal axis; support means for holding said electronic device so that its contact areas are disposed towards said first surface of said lead frame, said support means adjustably translatable both along said first and second axes and non-adjustably translatable along a third orthogonal axis which is perpendicular to said lead frame surfaces, said support means further adjustably rotatable about said third axis; anvil means disposed along said third axis opposite said second surface of said lead frame, said anvil means fixed in said first axis, but adjustably translatable along said second and third axes; optical means for imaging said advancing and support means; processor means responsive to said optical means, for determining positional differences between bond sites on a lead frame and contact areas on an electronic device, and causing movements of said support means and advancing means on axes along which said means are respectively, adjustably translatable or rotatable, to reduce said positional differences, whereby reliable bonding is enabled to occur. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification