Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
2000-09-06
2002-01-15
Niebling, John F. (Department: 2812)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C427S256000, C427S555000, C427S099300, C257S678000, C438S014000
Reexamination Certificate
active
06339728
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method for marking a surface of a singulated article, such as a packaged semiconductor device, using a green laser.
BACKGROUND ART
As the production rates of semiconductor devices (frequently referred to as “chips”), including packaged dies, continue to increase, chip manufacturers search for ways to quickly and efficiently mark their products. Typically, finished semiconductor devices are marked with information, such as the company name, part number or serial number, and/or lot number. It is difficult for current marking techniques to efficiently meet the demands of increasing production rates.
Because of the deficiencies associated with ink stamping, it has become increasingly popular to use a laser beam to mark the surface of a chip package. Unlike ink stamping, laser marking is fast, requires no curing time, and produces a consistently high-quality mark with minimal set-up time. A laser beam basically burns a permanent mark into the surface of the article of manufacture; whereas inked marks have a tendency to smear, degrade, fade or erode. In the case of a packaged chip, the laser marking creates a different reflectivity from the rest of the package surface. Thus, by holding the chip at an angle to a light source, the information inscribed on the chip by the laser can be easily read.
Various machines and methods have been developed for marking a chip or other article of manufacture with an infrared laser. However, infrared lasers cannot mark on bare disc silicon because energy is transmitted though the silicon damaging the active metal layer.
Accordingly, there exists a need for methodology for marking that efficiently utilizes the speed and accuracy of a laser to precisely and clearly mark singulated semiconductor devices with better depth control.
SUMMARY OF THE INVENTION
An advantage of the present invention is an efficient, cost-effective method for marking semiconductor devices yielding better mark quality and reducing debris formation.
Another advantage of the present invention is a method for marking a silicon semiconductor device without damaging underlying active metal layers.
According to one aspect of the invention, a method for marking a surface of a singulated article, the method comprising the steps of positioning at least one article at a first marking location to be marked by a green laser beam, and marking said at least one article at said first marking location carrier for a semiconductor device is provided.
Other advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description. The embodiments shown and described provide illustration of the best mode contemplated for carrying out the invention. The invention is capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawings are to be regarded as illustrative in nature, and not as restrictive.
REFERENCES:
patent: 6127069 (2000-10-01), Balz
patent: 6217949 (2001-04-01), Corbett
Blish Richard C.
Nguyen Quang D.
Niebling John F.
Stevenson André C
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