Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
2001-12-27
2003-11-11
Niebling, John F. (Department: 2812)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
Reexamination Certificate
active
06646671
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to processing of semiconductor devices, and more particularly to a system and method for improving the performance of machines used in providing semiconductor packages.
BACKGROUND OF THE INVENTION
During processing of semiconductor devices, the semiconductor device, or package, is typically marked and tested. During processing, a laser marking module and a lead scanner are typically sued. The laser marking module and the lead scanner are generally integrated. The lead scanner can be an ATS300 lead scanner. The mark module includes a marking station where the semiconductor packages are marked and an unloader. The unloader includes a good bin and a reject bin. Coupled to the marking station is the lead scanner. The lead scanner is coupled between the marking station and the unloader. After the semiconductor packages have been marked by the marking station, the lead scanner tests the marked semiconductor packages to determine whether the leads function properly.
The semiconductor packages are provided from the lead scanner to the unloader. Based on the outcome of the test(s) performed by the lead scanner, a particular semiconductor package may be provided to one of the bins in the unloader. If the semiconductor package has passed the test(s) performed by the lead scanner, then the semiconductor package is provided to the good bin. The good bin includes a receptacle to contain the good semiconductor packages which have passed the inspection by the lead scanner. Otherwise, the semiconductor package is provided to the reject bin. Thus, semiconductor packages which do not pass inspection by the lead scanner can be discarded.
Although the laser marking module and lead scanner can function together to mark and test semiconductor packages, one of ordinary skill in the art will readily realize that jams between the lead scanner and laser marking module often occur. The lead scanner includes a counter and switches for controlling the lead scanner. The counter counts the number of semiconductor packages that have been provided from the lead scanner. Similarly, the good bin of the unloader includes a counter for counting the number of good semiconductor packages received. Thus, the counter for the lead scanner can count a different number than the counter for the unloader. This is because the counter for the lead scanner counts each package exiting the lead scanner, while the counter for the good bin only counts the semiconductor packages which are provided to the good bit. Typically, both the counter and the counter count backwards from a particular, user set number. Each of these numbers can be manually set.
For example, suppose that the counter for the lead scanner is set to twenty units per receptacle. Similarly, suppose that the counter for the good bin is set to twenty units. Each time a semiconductor package is released by the lead scanner to either the good bin or the reject bin, the counter for the lead scanner decrements. Thus, for every semiconductor package tested by the lead scanner, the counter for the lead scanner decrements. The counter for the good bin decrements each time the good bin receives a semiconductor package that has passed the tests performed by the lead scanner. However, the counter for the good bin does not change when a semiconductor package is rejected and placed in the reject bin.
Because the counters for the good bin and the lead scanner count different semiconductor packages (only semiconductor packages passing the test versus all semiconductor packages), the counter for the good bin can reach zero when the counter for the lead scanner is nonzero. When the counter for the good bin reaches zero, the marking module pauses to change the receptacles in the good bin. However, the lead scanner continues to attempt to provide another semiconductor package to the good bin. Because semiconductor packages are provided to the unloader when the unloader is changing the receptacle in the good bin, a jam will occur. At this time, production may be halted and the efficiency of the lead scanner and marking module adversely affected. In particular, the yield for the laser marking module and lead scanner combination is reduced.
Accordingly, what is needed is a system and method for preventing jams between the unloader and the lead scanner. The present invention addresses such a need.
SUMMARY OF THE INVENTION
The present invention provides a method and system for synchronizing a laser marking device with a lead scanner. The laser marking device includes an unloader coupled to the lead scanner and is for marking each of a plurality of semiconductor packages including a plurality of leads. The lead scanner performs a test on the plurality of leads for the plurality of semiconductor packages. The unloader is for containing a portion of the plurality of semiconductor packages that passed the test. The method and system comprise providing an input receiving circuit, a reset circuit and an output relay. The input receiving circuit is coupled with the unloader and is for receiving an indication of a particular number of the plurality of semiconductor packages received by the unloader. The reset circuit is coupled with the lead scanner and the input receiving circuit and is capable of generating at least one reset signal for resetting the lead scanner in response to the particular number of the plurality of semiconductor packages being reached. The output relay is coupled with the lead scanner and the reset circuit. The output relay is for temporarily precluding the lead scanner from providing a semiconductor package to the unloader.
According to the system and method disclosed herein, the present invention provides a mechanism for improving the performance of the lead scanner and laser marking device.
REFERENCES:
patent: 6061081 (2000-05-01), Hasebe et al.
patent: 6415977 (2002-07-01), Rumsey
Chantaphan Surasee
Jitramas Naramitr
Namkang Watcharin
Sritulanont Somboon
Niebling John F.
Stevenson André C
Winstead Sechrest & Minick P.C.
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