Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
1998-06-08
2001-04-24
Karlsen, Ernest (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S765010
Reexamination Certificate
active
06222379
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to semiconductor manufacture and more particularly to an improved method and apparatus for packaging and testing semiconductor dice.
BACKGROUND OF THE INVENTION
Conventionally packaged semiconductor dice are tested several times during the manufacturing process. A probe test is conducted at the wafer level to test the gross functionality of the dice. Following singulation of the wafer and packaging of the individual dice, full functionality and burn-in tests are performed on each of the packaged die. These tests are typically performed using standardized equipment that provides an electrical interface between the external contacts on the package (e.g., terminal leads) and test circuitry.
For example, burn-in ovens are adapted to hold a large number of packaged dice in a chamber with temperature cycling capability. During the burn-in test the integrated circuits are electrically tested at different temperatures. A burn-in board mountable within the chamber, includes electrical connectors that mate with the external leads on the packaged dice to establish an electrical interconnection between the individually packaged dice and test circuitry. For packaged dice having a male external contact, such as terminal leads formed as pins, the burn-in board may include socket connectors. For packaged dice having female external contacts, such as flat pads in a land grid array, the burn-in board may include pogo pin connectors.
Because semiconductor dice are packaged in standardized configurations, the burn-in boards are also standardized. For example, one common semiconductor package for a single die is known as a small outline j-lead package (SOJ). A burn-in board for SOJ packages will include standardized sockets that mate with the j-leads for the packages. In addition, the spacing for the sockets will be such that a large number of packages can be mounted on a single board in a dense closely spaced array.
In addition to the boards being standardized, there is also associated equipment, such as automated handling apparatus, that is standardized for a particular package configuration. Other standardized packages for a single die include the dual in-line (DIP) package and the zigzag in-line package (ZIP).
Recently, semiconductor dice have been supplied by manufacturers in an unpackaged or bare configuration. A known good die (KGD) is an unpackaged die that has been tested to a quality and reliability level equal to the packaged product. To certify a die as a known good die the unpackaged die must be burn-in tested. This has led to the development of test carriers that hold a single unpackaged die for burn-in and other tests. Each test carrier houses a die for testing and also provides the electrical interconnection between the die and external test circuitry. Exemplary test carriers are disclosed in U.S. Pat. No. 5,302,891 to Wood et al. and U.S. Pat. No. 5,408,190 to Wood et al.
One aspect of these carriers is that they require specialized test equipment such as specialized burn-in boards and handling equipment that are different than the equipment used for testing packaged dice. In addition, the prior art carriers are larger than conventionally packaged dice and therefore require more and larger test equipment to achieve the same throughputs. It would be advantageous to provide a method for packaging and testing semiconductor dice that can be used with standardized test equipment.
In view of the foregoing, it is an object of the present invention to provide an improved method for packaging and testing semiconductor dice. It is another object of the present invention to provide a temporary package for a bare semiconductor die in which a temporary electrical connection can be made to the die for testing or other purposes. It is yet another object of the present invention to provide an improved method for testing semiconductor dice that uses a small outline temporary package and standard test equipment. It is a further object of the present invention to provide a temporary semiconductor package that has a JEDEC standard outline and JEDEC standard external contact configuration. Other objects advantages and capabilities of the present invention will become more apparent as the description proceeds.
SUMMARY OF THE INVENTION
In accordance with the present invention, an improved method for packaging and testing a semiconductor die is provided. The method, broadly stated, comprises forming a temporary package for a bare semiconductor die having a standard outline and external lead configuration that matches a conventional semiconductor package, and then testing the die using the temporary package and standardized testing apparatus. The standard outline and external lead configuration of the temporary package permits standardized burn-in boards and automated package handling equipment to be used during a test procedure for known good die. In an illustrative embodiment, the temporary package is formed in the configuration of a small outline j-bend (SOJ) plastic package.
The temporary package includes a base, an interconnect and a force applying mechanism. The package base can be either plastic or ceramic. In an illustrative embodiment, the package base is formed using a ceramic lamination process. The package base can also be formed of plastic using a 3-D injection molding process or either ceramic or plastic using a ceramic dip formation (Cerdip) process. The package base includes metallic conductors in electrical communication with external contacts formed as j-bend leads.
The interconnect for the package is mounted to the base and wire bonded to the conductors formed on the package base. In the illustrative embodiment, the interconnect is formed of silicon and includes conductive lines and raised contact members that contact and establish electrical communication with the bond pads on the die. The interconnect can also be formed with microbump contact members mounted on a plastic film similar to two layer TAB tape.
The force applying mechanism for the package includes a pressure plate, a spring and a cover. The force applying mechanism functions to secure the die within the base and to maintain the die and interconnect in electrical contact. The force applying mechanism is secured to the base with a latching mechanism. Several different embodiments for the latching mechanism are disclosed including a sliding latch and a T-shaped latch. In some embodiments the pressure plate and spring are replaced by an elastomeric member.
The package is assembled by optically aligning the die and the interconnect. Prior to the alignment procedure the interconnect is mounted within the package base by wire bonding. During the alignment procedure, the die and force applying mechanism of the package are held by an assembly tool. Flip chip optical alignment is used to align the bond pads on the die to the contact members on the interconnect. The assembly tool then places the die on the interconnect and attaches the force applying mechanism to the package base.
In an alternate embodiment of the package, the die is mounted circuit side up within the package. This arranges the bond pads for the die and the external leads for the package in a configuration that is identical to a conventional packaged die.
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patent
Akram Salman
Farnworth Warren M.
Hembree David R.
Wood Alan G.
Gratton Stephen A.
Karlsen Ernest
Micro)n Technology, Inc.
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