Electricity: measuring and testing – Measuring – testing – or sensing electricity – per se – With rotor
Reexamination Certificate
1999-01-20
2002-03-05
Nguyen, Vinh P. (Department: 2858)
Electricity: measuring and testing
Measuring, testing, or sensing electricity, per se
With rotor
C324S765010, C324S758010
Reexamination Certificate
active
06353312
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to computer-aided methods and systems for manufacturing products in a high volume, automated, continuous process and, more particularly, to improved methods and apparatus for automatically positioning electronic dice within component packages.
2. State of the Art
Integrated circuit devices are well-known in the prior art. Such devices, or so-called “dice,” are normally designed to be supported or carried in a package having a plurality of pins or leads. The package serves as a carrier and as a heat sink and is normally square or rectangular in shape. The packages, which includes a cavity in which the integrated circuit die is placed, may be formed of metal, ceramic or plastic components. After the integrated circuit is secured in the cavity of the package, a component “lid” is typically placed over an exposed surface of the circuit. A bottom surface of the lid includes a “pre-form” material such as epoxy or solder that is used to secure the lid over the circuit to provide a protective cover. The pre-form is cured by placing the package in a furnace.
Packaging unusable dice which must be scrapped after testing is inefficient and costly. Accordingly, the dice are often tested for continuity during the manufacturing process. This has been accomplished by placing dice in temporary packages and subjecting the assembled package to extensive testing, which includes burn-in and discrete testing. Discrete testing includes testing the devices for speed and for errors which may occur after assembly and after burn-in. Burn-in testing accelerates failure mechanisms such that devices which have the potential to fail later but which failure would not otherwise be apparent at nominal test conditions can be eliminated.
However, testing unpackaged dice requires a significant amount of handling. The temporary package must not only be compatible with test and burn-in procedures, but must also secure the die without damaging the die at the bond pads or elsewhere during the process. Bonds pads are conductive areas on the face of the die which are used as an interconnect for connecting the die circuitry to the package. The positioning of the die within the cavity of the temporary package is therefore critical since the placement of the die bond pads relative to the temporary package electrical interconnects must be properly aligned in order to subject the die to such extensive testing.
Precising die packaging includes mechanically locating a component in a precise position or placement. Various “precising” methods for this purpose are known in the art. However, there have been several problems associated with such precising methods and systems. For example, it has been difficult to position the die bond pads in electrical contact with temporary package electrical interconnects in an accurate and consistent manner so as to facilitate a high volume, continuous manufacture of temporary packages. Another disadvantage associated with the prior art is that the die is often destroyed upon contact with the temporary package. Moreover, a significant investment in the costly integrated circuit device is often lost when the positioning of the die within the temporary package is not properly aligned. Accurate placement and positioning of the die in the temporary package is thus critical to providing acceptable results.
One attempt to overcome the problems associated with the prior art has been to precise die and packages by mechanical fixturing. However, assembly tolerances used in mechanical fixturing techniques are often insufficient to prevent improper alignment. Mechanical fixturing also leads to damage of the die or temporary package. While such techniques have proven useful in improving the accuracy and reliability of the die placement, these techniques do not enable dice to be precisely positioned within temporary packages in a manner that allows production efficiencies capable of supporting large volume operations.
Accordingly, there remains a long-felt need in the semiconductor industry to provide for improved methods and apparatus for manufacturing integrated circuit temporary packages in a high volume, cost-efficient and reliable manner which includes automatically positioning integrated circuit dice within the temporary packages such that die bond pads are in electrical contact with temporary package electrical interconnects to allow extensive testing to be performed.
BRIEF SUMMARY OF THE INVENTION
It is thus a primary object of the present invention to provide computer-controlled methods and apparatus for automating the positioning of integrated circuit devices or dice within temporary packages utilizing a high volume, continuous process.
It is another object of the invention to provide an automated apparatus for the positioning of electronic dice within temporary packages that is used in-line with other machines to facilitate formation of assembled packages which may then be subjected to continuity testing and the like.
It is yet another object of the invention to describe methods and systems for accurately positioning electronic dice within temporary packages in a reliable, cost-effective manner.
It is still another object of the invention to provide methods and apparatus for continuous positioning of integrated circuit dice within temporary packages in a production line while significantly reducing the percentage of dice and temporary packages in which continuity is not established.
Yet another object of the invention is to provide multiple inspections of the die and temporary package prior to, during and after placement of the die within the temporary package. By inspecting the die at various stages of assembly, dice which are not properly aligned or positioned can be repositioned to maximize the number of electrical contacts between the die bond pads and temporary package electrical interconnects.
It is still another object of the invention to preferably use multiple cameras to facilitate precise placement of the dice in the temporary packages in a continuous manner, thereby significantly enhancing the efficiency of the processing line and increasing the number of packages in which continuity is established.
It is still a further object of the invention to provide an apparatus for placing dice in temporary packages wherein the packages are supported on carriers such as boats or trays that are conveyed along a path through a predetermined assembly/diassembly position. A carrier preferably includes a body portion and at least one side rail having a plurality of spaced openings therein. The carrier may be formed of plastic or metal. The apparatus further includes an indexing mechanism that functions to place each temporary package in the predetermined assembly/diassembly position to allow the integrated circuit die to be positioned precisely therein.
Still another object of the present invention is to provide a method and apparatus which utilizes previously stored die characteristics for a die in a known temporary package and in a known boat to disassemble electrical dice and temporary packages from one another based on predetermined parameters and to classify the die appropriately.
According to more specific aspects of the present invention, an assembly system is provided to place die bond pads in electrical contact with temporary package electrical interconnects. Once the die bond pads are in contact with the electrical interconnects, the temporary package can be placed in a standard device tester and subjected to extensive testing. Such testing includes burn-in testing and the like to establish various die characteristics and eliminate mortality. These characteristics, while not meant to be limiting, include the quality of the electrical contact between the die and the temporary package in addition to classifying the die in the temporary package based on speed grade characteristics.
The method and apparatus in accordance with the present invention includes a system which picks up and places a die on
Farnworth Warren M.
Folaron Jennifer L.
Folaron Robert J.
Hembree David R.
Jacobson John O.
Micro)n Technology, Inc.
Nguyen Vinh P.
TraskBritt
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